Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/08/13
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
250 PM MST TUE AUG 6 2013
.UPDATE...
UPDATED AVIATION DISCUSSION...
&&
.SYNOPSIS...
SKIES WILL GRADUALLY CLEAR TONIGHT AS DRIER AIR MOVES INTO THE
REGION FROM THE SOUTHWEST. DRY WEATHER WILL PREVAIL FOR MUCH OF THE
UPCOMING WEEK WITH PRECIP CHANCES CONFINED MAINLY TO EASTERN
ARIZONA. TEMPERATURES WILL REMAIN BELOW NORMAL WEDNESDAY...BUT COULD
APPROACH THE 110 DEGREE MARK BY EARLY NEXT WEEK.
&&
.DISCUSSION...
REGIONAL RADAR MOSAIC INDICATES SHOWERS ARE TAPERING OFF ACROSS THE
PHOENIX METRO...WHILE NEW SHOWERS AND THUNDERSTORMS ARE DEVELOPING
ACROSS EASTERN/SOUTHERN ARIZONA. A BAND OF THUNDERSTORMS WERE ALSO
LOCATED ACROSS YAVAPAI COUNTY AND WERE MOVING SOUTHWARD /IN THE
DEFORMATION AREA OF THE UPPER LEVEL SHORTWAVE/. MEANWHILE TO THE
WEST...JUST YOUR AVERAGE AUGUST DAY WITH TEMPS AROUND 100 WITH SUNNY
SKIES AND NO PRECIP TO SPEAK OF.
17Z HRRR MODEL SEEMS TO HAVE CAUGHT ON TO THE PRESENT SITUATION AND
ADVERTISES CONVECTION TO MOVE INTO SOUTHERN GILA COUNTY LATER THIS
AFTERNOON...MEANWHILE THE YAVAPAI STORMS WILL TRY AND DRIFT
SOUTHWARD INTO THE FAR NORTHEAST CORNER OF THE PHX METRO. SPC MESO
PAGE INDICATES A FEW HUNDRED J/KG OF MLCAPE RESIDES IN THIS AREA
WHICH HAS BEEN LARGELY FREE OF RAIN TODAY...SEEMS PLAUSIBLE A FEW
STORMS COULD SURVIVE IN THAT ENVIRONMENT. THIS IS IN LINE WITH
PREVIOUS UPDATES TO THE FORECAST...AND I WILL HANG ONTO 10-20 POPS
ACROSS THE PHOENIX AREA THROUGH THE EVENING...WITH HIGHER POPS IN
THE MOUNTAINS TO THE EAST. THE TROUGH WILL MOVE OUT OF THE AREA
TONIGHT AND SUBSIDENCE BEHIND THE LOW SHOULD DRY THINGS OUT BEFORE
MIDNIGHT.
THE FORECAST FOR WEDNESDAY THROUGH NEXT WEEK IS LARGELY UNCHANGED AS
THE UPPER FLOW BECOMES MORE SOUTHWESTERLY AND MOISTURE GETS
DISPLACED INTO NEW MEXICO. COULD SEE SOME ISOLATED MOUNTAIN
SHOWERS/THUNDERSTORMS WEDNESDAY/THURSDAY GIVEN LINGERING PWATS
AROUND 1.1-1.3 INCHES...BUT CHANCES SHOULD REMAIN BELOW CLIMO GIVEN
UNFAVORABLE FLOW ALOFT ALL THE WAY THROUGH EARLY NEXT WEEK.
A GRADUAL INCREASE IN TEMPERATURES WILL TAKE PLACE THROUGH THE
UPCOMING WEEKEND...BUT WITH THE UPPER LOW TO THE NORTHWEST...500MB
HEIGHTS WILL REMAIN BELOW 590DM AND AFTERNOON HIGHS WILL STAY WITHIN
A COUPLE DEGREES OF NORMAL THROUGH SATURDAY. MODELS ARE IN GOOD
AGREEMENT LIFTING THE UPPER LOW NORTHEASTWARD LATE THIS WEEKEND
ALLOWING FOR HEIGHTS TO INCREASE ACROSS THE DESERT SOUTHWEST AND
SHIFTING THE SUBTROPICAL HIGH CLOSER TO THE FOUR CORNERS REGION.
WARMING TEMPERATURES SUNDAY AND MONDAY ARE EXPECTED WITH SOME LOWER
DESERT HIGHS AROUND 110 DEGREES. AN INCREASE IN BOUNDARY LAYER
MOISTURE IS EXPECTED ACROSS FAR EASTERN ARIZONA EARLY NEXT WEEK
ALLOWING FOR SLIGHTLY BETTER CHANCES FOR MONSOON STORMS MAINLY
ACROSS THE HIGHER TERRAIN EAST OF PHOENIX.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SHOWERS AND CLOUDINESS WILL CONTINUE TO DECLINE OVER THE PHOENIX
AREA THIS AFTERNOON. HOWEVER...STORMS OVER PINAL COUNTY AND FAR
NORTHEAST MARICOPA COUNTY ARE STILL POSSIBLE THROUGH 03Z AND COULD
BRUSH NORTH AND EAST PORTIONS OF THE METRO BUT PROBABILITY TOO LOW
TO REFLECT IN THE TAFS. SURFACE WINDS WILL FAVOR EASTERLY DIRECTIONS
THROUGH WEDNESDAY MORNING EXCEPT FOR A SHORT PERIOD LATE THIS
AFTERNOON AND EVENING. ANTICIPATE CLEARING SKIES OVERNIGHT.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
CLEAR SKIES CAN BE EXPECTED THROUGH WEDNESDAY. WINDS WILL FAVOR
SOUTHERLY DIRECTIONS OVER THE LOWER COLORADO RIVER VALLEY...WITH
GUSTS OF 20-25 KTS IN THE AFTERNOONS. WINDS WILL BE LIGHTER OVER THE
IMPERIAL VALLEY AND FAVOR EASTERLY DIRECTIONS IN THE
AFTERNOONS...WESTERLY AT NIGHT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
AN AREA OF LOW PRESSURE WILL REMAIN SITUATED ALONG THE CALIFORNIA
COAST THURSDAY THROUGH THE WEEKEND KEEPING A RATHER DRY SOUTHWEST
FLOW ALOFT IN PLACE ACROSS THE AREA. THE ONLY THREAT FOR SHOWERS OR
THUNDERSTORMS WILL BE OVER THE HIGHER TERRAIN AREAS EAST OF PHOENIX
STARTING ON SATURDAY AND CONTINUING INTO MONDAY. A SLIGHT WARMING
TREND IS EXPECTED WITH HIGH TEMPERATURES CLIMBING FROM NEAR OR
SLIGHTLY BELOW NORMAL VALUES THURSDAY TO A FEW DEGREES ABOVE CLIMO
BY THE WEEKEND. MINIMUM HUMIDITIES WILL RANGE FROM THE LOW TEENS TO
SINGLE DIGITS OVER THE LOWER DESERTS THROUGH THE PERIOD...WITH FAIR
RECOVERIES AT NIGHT. NO SIGNIFICANT WIND IS ANTICIPATED...JUST LOCAL
AFTERNOON AND EARLY EVENING GUSTINESS FAVORING UPSLOPE OR THE
SOUTHWEST.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/KUHLMAN
AVIATION...AJ
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
108 PM MST TUE AUG 6 2013
.SYNOPSIS...
SKIES WILL GRADUALLY CLEAR TONIGHT AS DRIER AIR MOVES INTO THE
REGION FROM THE SOUTHWEST. DRY WEATHER WILL PREVAIL FOR MUCH OF THE
UPCOMING WEEK WITH PRECIP CHANCES CONFINED MAINLY TO EASTERN
ARIZONA. TEMPERATURES WILL REMAIN BELOW NORMAL WEDNESDAY...BUT COULD
APPROACH THE 110 DEGREE MARK BY EARLY NEXT WEEK.
&&
.DISCUSSION...
REGIONAL RADAR MOSAIC INDICATES SHOWERS ARE TAPERING OFF ACROSS THE
PHOENIX METRO...WHILE NEW SHOWERS AND THUNDERSTORMS ARE DEVELOPING
ACROSS EASTERN/SOUTHERN ARIZONA. A BAND OF THUNDERSTORMS WERE ALSO
LOCATED ACROSS YAVAPAI COUNTY AND WERE MOVING SOUTHWARD /IN THE
DEFORMATION AREA OF THE UPPER LEVEL SHORTWAVE/. MEANWHILE TO THE
WEST...JUST YOUR AVERAGE AUGUST DAY WITH TEMPS AROUND 100 WITH SUNNY
SKIES AND NO PRECIP TO SPEAK OF.
17Z HRRR MODEL SEEMS TO HAVE CAUGHT ON TO THE PRESENT SITUATION AND
ADVERTISES CONVECTION TO MOVE INTO SOUTHERN GILA COUNTY LATER THIS
AFTERNOON...MEANWHILE THE YAVAPAI STORMS WILL TRY AND DRIFT
SOUTHWARD INTO THE FAR NORTHEAST CORNER OF THE PHX METRO. SPC MESO
PAGE INDICATES A FEW HUNDRED J/KG OF MLCAPE RESIDES IN THIS AREA
WHICH HAS BEEN LARGELY FREE OF RAIN TODAY...SEEMS PLAUSIBLE A FEW
STORMS COULD SURVIVE IN THAT ENVIRONMENT. THIS IS IN LINE WITH
PREVIOUS UPDATES TO THE FORECAST...AND I WILL HANG ONTO 10-20 POPS
ACROSS THE PHOENIX AREA THROUGH THE EVENING...WITH HIGHER POPS IN
THE MOUNTAINS TO THE EAST. THE TROUGH WILL MOVE OUT OF THE AREA
TONIGHT AND SUBSIDENCE BEHIND THE LOW SHOULD DRY THINGS OUT BEFORE
MIDNIGHT.
THE FORECAST FOR WEDNESDAY THROUGH NEXT WEEK IS LARGELY UNCHANGED AS
THE UPPER FLOW BECOMES MORE SOUTHWESTERLY AND MOISTURE GETS
DISPLACED INTO NEW MEXICO. COULD SEE SOME ISOLATED MOUNTAIN
SHOWERS/THUNDERSTORMS WEDNESDAY/THURSDAY GIVEN LINGERING PWATS
AROUND 1.1-1.3 INCHES...BUT CHANCES SHOULD REMAIN BELOW CLIMO GIVEN
UNFAVORABLE FLOW ALOFT ALL THE WAY THROUGH EARLY NEXT WEEK.
A GRADUAL INCREASE IN TEMPERATURES WILL TAKE PLACE THROUGH THE
UPCOMING WEEKEND...BUT WITH THE UPPER LOW TO THE NORTHWEST...500MB
HEIGHTS WILL REMAIN BELOW 590DM AND AFTERNOON HIGHS WILL STAY WITHIN
A COUPLE DEGREES OF NORMAL THROUGH SATURDAY. MODELS ARE IN GOOD
AGREEMENT LIFTING THE UPPER LOW NORTHEASTWARD LATE THIS WEEKEND
ALLOWING FOR HEIGHTS TO INCREASE ACROSS THE DESERT SOUTHWEST AND
SHIFTING THE SUBTROPICAL HIGH CLOSER TO THE FOUR CORNERS REGION.
WARMING TEMPERATURES SUNDAY AND MONDAY ARE EXPECTED WITH SOME LOWER
DESERT HIGHS AROUND 110 DEGREES. AN INCREASE IN BOUNDARY LAYER
MOISTURE IS EXPECTED ACROSS FAR EASTERN ARIZONA EARLY NEXT WEEK
ALLOWING FOR SLIGHTLY BETTER CHANCES FOR MONSOON STORMS MAINLY
ACROSS THE HIGHER TERRAIN EAST OF PHOENIX.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SCT TO NUMEROUS LIGHT -SHRA WILL AFFECT CNTRL ARIZONA TERMINALS
THROUGH AT LEAST 18Z...WITH SOME LESSER CHANCE OF RAIN LINGERING
INTO THE EARLY AFTERNOON. CIGS SHOULD REMAIN AOA 8K FT WITH VFR
VSBYS...THOUGH ISOLD AREAS COULD VERY BRIEFLY DIP INTO MVFR
CATEGORIES IN MORE MDT SHRA. COVERAGE AND PROBABILITIES OF LOWER
FLIGHT CATEGORIES ARE FAR TOO REMOTE TO EVEN MENTION IN THIS TAF
PACKAGE. PRIMARY IMPACTS WILL BE PERIODIC WET CONDITIONS FOR GROUNDS
CREWS AND PARTIAL MTN OBSCURATION ON DEPARTURE/APPROACH.
SFC WINDS WILL GENERALLY REMAIN ELY THROUGH THE MORNING BEFORE
GRADUALLY VEERING TO SWLY DURING THE AFTERNOON. THERE MAY BE
OCCASIONAL PERIODS OF MORE VARIABLE WINDS WITHIN SHRA THIS MORNING.
OTHERWISE...CIGS SHOULD SLOWLY LIFT AND CLEAR BY WEDNESDAY MORNING.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
FAIRLY EXTENSIVE HIGH CLOUDS WILL AFFECT TERMINALS THROUGH TUESDAY
EVENING...WITH SHOWERS REMAINING WELL TO THE EAST INTO CNTRL
ARIZONA. WINDS WILL GENERALLY REMAIN FROM A SLY/SELY DIRECTION
THROUGH THE EVENING WITH OCCASIONAL HIGHER GUSTS AT KBLH. WITH
MODERATE CONFIDENCE...HAVE SFC WINDS SHIFTING TO WLY AT KIPL AFTER
SUNSET.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
AN AREA OF LOW PRESSURE WILL REMAIN SITUATED ALONG THE CALIFORNIA
COAST THURSDAY THROUGH THE WEEKEND KEEPING A RATHER DRY SOUTHWEST
FLOW ALOFT IN PLACE ACROSS THE AREA. THE ONLY THREAT FOR SHOWERS OR
THUNDERSTORMS WILL BE OVER THE HIGHER TERRAIN AREAS EAST OF PHOENIX
STARTING ON SATURDAY AND CONTINUING INTO MONDAY. A SLIGHT WARMING
TREND IS EXPECTED WITH HIGH TEMPERATURES CLIMBING FROM NEAR OR
SLIGHTLY BELOW NORMAL VALUES THURSDAY TO A FEW DEGREES ABOVE CLIMO
BY THE WEEKEND. MINIMUM HUMIDITIES WILL RANGE FROM THE LOW TEENS TO
SINGLE DIGITS OVER THE LOWER DESERTS THROUGH THE PERIOD...WITH FAIR
RECOVERIES AT NIGHT. NO SIGNIFICANT WIND IS ANTICIPATED...JUST LOCAL
AFTERNOON AND EARLY EVENING GUSTINESS FAVORING UPSLOPE OR THE
SOUTHWEST.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/KUHLMAN
AVIATION...MO
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
916 AM MST TUE AUG 6 2013
.SYNOPSIS...
A TEMPORARY INCREASE IN MONSOON MOISTURE ASSOCIATED WITH AN UPPER
LEVEL LOW WILL BRING PERIODS OF LIGHT RAIN TODAY AND THE POSSIBILITY
OF AN ISOLATED THUNDERSTORM. THE EXTENSIVE CLOUD COVER AND LIGHT
RAIN WILL LEAD TO A MUCH COOLER DAY TODAY WITH HIGHS WELL BELOW
NORMAL. A DRYING TREND WILL START ON WEDNESDAY AND WILL CONTINUE
INTO THE WEEKEND...KEEPING PRECIPITATION CHANCES CONFINED MAINLY TO
EASTERN ARIZONA.
&&
.DISCUSSION...
STILL LOOKING AT QUITE A BIT OF SHOWERS ACROSS THE REGION AS OF
16Z...AS A SHORTWAVE TROUGH SLOWLY MOVES THROUGH SONORA AND ARIZONA.
RAINFALL TOTALS HAVE BEEN ON THE LOW SIDE SO FAR...GENERALLY A FEW
HUNDREDTHS TO 0.15 INCHES VALLEY-WIDE. NOT SURPRISINGLY...THIS HAS
ALSO PUT A SERIOUS DENT IN OUR TEMPERATURES. READINGS AS OF 16Z ARE
ONLY IN THE LOW/MID 70S ACROSS THE METRO...EVEN SKY HARBOR IS STILL
SITTING IN THE UPPER 70S. MEANWHILE TO THE WEST...DRY CONDITIONS
REMAIN IN PLACE AND TEMPS HAVE BEEN WARMING ON SCHEDULE.
THE SHORTWAVE TROUGH WILL MOVE THROUGH CENTRAL ARIZONA LATER THIS
MORNING AND A GRADUAL DRYING TREND SHOULD COMMENCE AFTER NOON. RADAR
MOSAIC ALREADY STARTING TO INDICATE THE WESTERN EDGE OF THE PRECIP
IS BREAKING DOWN OVER WESTERN MARICOPA COUNTY...AND THIS TREND
SHOULD CONTINUE THROUGH THE AFTERNOON HOURS. THAT BEING SAID...A
SECONDARY TROUGH SOUTH OF PIMA COUNTY WILL MOVE INTO ARIZONA LATER
TODAY. HI-RES WRF MODELS AND THE HRRR INDICATE CONVECTION SHOULD
DEVELOP OVER THE MOUNTAINS EAST OF PHOENIX AFTER 21Z...AND I
INCREASED POPS IN THESE AREAS BY ABOUT 10-20 PERCENT. RAP/HRRR MODEL
ALSO INDICATING SCATTERED SHOWERS REMAINING IN PLACE ACROSS THE
METRO THROUGH MID AFTERNOON. I INCREASED POPS ACROSS THE METRO A BIT
AS WELL THROUGH 00Z ALTHOUGH THEY SHOULD BE SCATTERED IN NATURE. THE
THREAT FOR SEVERE WEATHER EAST OF PHOENIX APPEARS SLIM GIVEN MOSTLY
MOIST ADIABATIC PROFILES...BUT THUNDER CERTAINLY SEEMS PLAUSIBLE IN
AREAS THAT HAVE REMAINED DRY THIS MORNING.
TEMPERATURES ARE A HUGE CHALLENGE TODAY. IF CLOUDS HANG AROUND MUCH
PAST 1-2PM...WE DONT STAND A CHANCE OF GETTING OUT OF THE UPPER
80S. WITH A LITTLE CLEARING...LOWER 90S SEEMS A MORE LIKELY
SOLUTION. I LOWERED HIGHS A BIT AND AM NOW GOING WITH HIGHS AROUND
87-92 IN THE METRO. EITHER WAY...NOWHERE NEAR NORMAL FOR EARLY
AUGUST. FORECAST A LITTLE MORE CLEAR-CUT FROM YUMA WESTWARD...HIGHS
IN THE LOWER 100S SEEMS LIKE A SAFE BET GIVEN SUNNY SKIES.
&&
.PREVIOUS DISCUSSION...
THE SOUTHERN VORT CENTER WILL QUICKLY EXIT THE AREA BY EARLY
EVENING...MOVING INTO NORTHERN ARIZONA BY MIDNIGHT TONIGHT. BEHIND
THIS...MUCH DRIER WESTERLY FLOW WILL SLIDE INTO THE AREA ENDING ANY
RAIN CHANCES AND BRINGING CLEARING SKIES TONIGHT. BOUNDARY LAYER
MOISTURE WILL TAKE A BIT LONGER TO BE SCOURED OUT AND ONCE DAYTIME
MIXING KICKS ON WEDNESDAY...SURFACE DEW POINTS WILL BE BACK IN THE
40/50S AND MORE LIKE 30/40S FOR THURSDAY THROUGH SATURDAY.
AFTER WEDNESDAY...THE MUCH DRIER UPPER LEVEL PATTERN WILL DOMINATE
ACROSS THE DESERT SOUTHWEST. A NEARLY STATIONARY CLOSED UPPER LOW
SITUATED OFF THE CALIFORNIA COAST WILL FINALLY COME ASHORE SOMETIME
WEDNESDAY LOWERING HEIGHTS ACROSS OUR REGION. PWATS FALL TO BELOW AN
INCH BY THURSDAY AND 1000-700MB MIXING RATIOS FALL TO AROUND 5 G/KG.
A GRADUAL INCREASE IN TEMPERATURES WILL TAKE PLACE THROUGH THE
UPCOMING WEEKEND...BUT WITH THE UPPER LOW TO THE NORTHWEST...500MB
HEIGHTS WILL REMAIN BELOW 590DM AND AFTERNOON HIGHS WILL STAY WITHIN
A COUPLE DEGREES OF NORMAL THROUGH SATURDAY. MODELS ARE IN GOOD
AGREEMENT LIFTING THE UPPER LOW NORTHEASTWARD LATE THIS WEEKEND
ALLOWING FOR HEIGHTS TO INCREASE ACROSS THE DESERT SOUTHWEST AND
SHIFTING THE SUBTROPICAL HIGH CLOSER TO THE FOUR CORNERS REGION.
WARMING TEMPERATURES SUNDAY AND MONDAY ARE EXPECTED WITH SOME LOWER
DESERT HIGHS AROUND 110 DEGREES. AN INCREASE IN BOUNDARY LAYER
MOISTURE IS EXPECTED ACROSS FAR EASTERN ARIZONA EARLY NEXT WEEK
ALLOWING FOR SLIGHTLY BETTER CHANCES FOR MONSOON STORMS MAINLY
ACROSS THE HIGHER TERRAIN EAST OF PHOENIX.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA...INCLUDING KPHX...KIWA AND KSDL...
SCT TO NUMEROUS LIGHT -SHRA WILL AFFECT CNTRL ARIZONA TERMINALS
THROUGH AT LEAST 18Z...WITH SOME LESSER CHANCE OF RAIN LINGERING
INTO THE EARLY AFTERNOON. CIGS SHOULD REMAIN AOA 8K FT WITH VFR
VSBYS...THOUGH ISOLD AREAS COULD VERY BRIEFLY DIP INTO MVFR
CATEGORIES IN MORE MDT SHRA. COVERAGE AND PROBABILITIES OF LOWER
FLIGHT CATEGORIES ARE FAR TOO REMOTE TO EVEN MENTION IN THIS TAF
PACKAGE. PRIMARY IMPACTS WILL BE PERIODIC WET CONDITIONS FOR GROUNDS
CREWS AND PARTIAL MTN OBSCURATION ON DEPARTURE/APPROACH.
SFC WINDS WILL GENERALLY REMAIN ELY THROUGH THE MORNING BEFORE
GRADUALLY VEERING TO SWLY DURING THE AFTERNOON. THERE MAY BE
OCCASIONAL PERIODS OF MORE VARIABLE WINDS WITHIN SHRA THIS MORNING.
OTHERWISE...CIGS SHOULD SLOWLY LIFT AND CLEAR BY WEDNESDAY MORNING.
SOUTHEAST CA AND SOUTHWEST AZ...INCLUDING KIPL AND KBLH...
FAIRLY EXTENSIVE HIGH CLOUDS WILL AFFECT TERMINALS THROUGH TUESDAY
EVENING...WITH SHOWERS REMAINING WELL TO THE EAST INTO CNTRL
ARIZONA. WINDS WILL GENERALLY REMAIN FROM A SLY/SELY DIRECTION
THROUGH THE EVENING WITH OCCASIONAL HIGHER GUSTS AT KBLH. WITH
MODERATE CONFIDENCE...HAVE SFC WINDS SHIFTING TO WLY AT KIPL AFTER
SUNSET.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH MONDAY...
AN AREA OF LOW PRESSURE WILL REMAIN SITUATED ALONG THE CALIFORNIA
COAST THURSDAY THROUGH THE WEEKEND KEEPING A RATHER DRY SOUTHWEST
FLOW ALOFT IN PLACE ACROSS THE AREA. THE ONLY THREAT FOR SHOWERS OR
THUNDERSTORMS WILL BE OVER THE HIGHER TERRAIN AREAS EAST OF PHOENIX
STARTING ON SATURDAY AND CONTINUING INTO MONDAY. A SLIGHT WARMING
TREND IS EXPECTED WITH HIGH TEMPERATURES CLIMBING FROM NEAR OR
SLIGHTLY BELOW NORMAL VALUES THURSDAY TO A FEW DEGREES ABOVE CLIMO
BY THE WEEKEND. MINIMUM HUMIDITIES WILL RANGE FROM THE LOW TEENS TO
SINGLE DIGITS OVER THE LOWER DESERTS THROUGH THE PERIOD...WITH FAIR
RECOVERIES AT NIGHT. NO SIGNIFICANT WIND IS ANTICIPATED...JUST LOCAL
AFTERNOON AND EARLY EVENING GUSTINESS FAVORING UPSLOPE OR THE
SOUTHWEST.
$$
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...LEINS/KUHLMAN
AVIATION...MO
FIRE WEATHER...CB
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
816 PM MDT WED AUG 7 2013
.UPDATE...
&&
.SHORT TERM...STRONG THUNDERSTORM ACTIVITY HAS SHIFTED EAST OF OUR
AREA. THERE WAS A SHOWER BAND OVER THE CENTRAL MOUNTAINS LIFTING
NORTH...BUT OVER THE LAST HOUR THIS AREA HAS SUDDENLY CLEARED.
THE ZONE BETWEEN THE SOUTHERLIES OVER US AND NORTHERLY FLOW OVER
WESTERN COLORADO LOOKS LIKE IT HAS BECOME A BIT MORE DYNAMIC...AND
APPARENTLY THIS REGION BECAME SUBSIDENT QUICKLY. ALREADY UPDATED
FOR LOWER POPS ACROSS MOST OF THE AREA...AND WHAT WE LEFT MAY
STILL BE TOO MUCH FOR THE NORTHWEST HALF OF OUR AREA. SOUTH WINDS
MAKE FOG FORMATION UNLIKELY...THOUGH IF THERE IS A LOT MORE
CLEARING THAN WE EXPECTED THERE COULD BE SOME STRATUS AWAY FROM
THE PALMER DIVIDE DOWNSLOPE.
&&
.AVIATION...VFR CONDITIONS THROUGH THURSDAY. SOUTH WINDS BECOMING
NORTH AT KDEN/KAPA THURSDAY MORNING. SCATTERED AFTERNOON
THUNDERSTORMS EXPECTED WITH FAIRLY HIGH CEILINGS BUT A CHANCE OF
GUSTY WINDS TO 30 KNOTS.
&&
.HYDROLOGY...STRONG CONVECTION HAS SHIFTED EAST. FOR MOST OF THE
AREA ONLY LIGHT SHOWERS EXPECTED IF ANYTHING. OVER LINCOLN COUNTY
STILL A CHANCE OF STORMS BUT THEY SHOULD BE LESS INTENSE AND
PRODUCE UNDER AN INCH OF RAIN...PROBABLY MUCH LESS.
&&
.PREV DISCUSSION... /ISSUED 351 PM MDT WED AUG 7 2013/
SHORT TERM...A COMPLEX PICTURE TODAY WITH SEVERAL UPPER LEVEL
SHORTWAVES EMBEDDED WITHIN AN OVERALL WEAK TROUGH CENTERED BACK
TOWARDS THE FOUR CORNERS REGION. SATELLITE WATER VAPOR LOOP CAPTURES
THINGS BEST. ONE FEATURE WENT BY THIS MORNING INTO EARLY AFTERNOON
WITH SOME THUNDERSTORM ACTIVITY EAST OF DENVER THAT HAS SINCE
MOVED OFF AND WEAKENED. THE PLATTEVILLE PROFILER SHOWS THIS I
BELIEVE CENTERED AROUND 600 MB. WIDESPREAD CLOUDINESS BUT NOT MUCH
RAIN FOR MOST OF THE REST OF THE FORECAST AREA WHICH HAS KEPT
TEMPERATURES ON THE COOL SIDE AND THUNDER LIMITED SO FAR. MORE SUN
AND WARMER CONDITIONS HAVE BEEN PRESENT SOUTH OF THE PALMER DIVIDE
AND A SECOND WAVE SEEN IN THE WATER VAPOR IMAGERY AND CAPTURED BY
THE RAP ANALYSES IS MOVING INTO THIS AREA WITH THUNDERSTORMS
RAPIDLY DEVELOPING. THESE SHOULD MOVE INTO THE PALMER DIVIDE
REGION OVER THE NEXT SEVERAL HOURS SO WILL CONTINUE THE FLASH
FLOOD WATCH. ALTHOUGH SURFACE WARMING HAS BEEN LIMITED ACROSS THE
PALMER DIVIDE COMPARED TO SOUTHEAST COLORADO DEW POINTS ARE QUITE
HIGH WITH 61 NOW AT LIMON. ANOTHER WAVE IS FOUND FARTHER SOUTH
MOVING NORTH INTO SOUTHWEST COLORADO AND THIS FEATURE IF IT HOLDS
TOGETHER COULD HELP SUPPORT MORE ACTIVITY LATER TONIGHT AGAIN TO
THE EAST OF DENVER. SEE THIS SECOND WAVE IN THE LATEST HRRR
FORECAST RUN FROM 19Z BUT HRRR KEEPS IT RATHER FAR TO THE SOUTH AS
IT APPROACHES NEAR 06Z. MAYBE TOO FAR SOUTH AS IT ALSO SEEMS TO BE
WITH THE CURRENT WAVE OF STORMS MOVING EAST OF PUB AND COS. MEANWHILE
AN UPPER LEVEL CIRCULATION REMAINS BEHIND NEAR THE FOUR CORNERS
AND WHAT IS LEFT OF THIS COULD BE A FACTOR TOMORROW OR SHIFT MORE
TO THE EAST.
THE MAIN PRECIPITATION LOOKS LIKE IT WILL CONTINUE TO STAY EAST
AND SOUTH OF DENVER. THERE IS ANOTHER AREA OF MORE SCATTERED
THUNDERSTORMS OVER THE FOOTHILLS OVER LARIMER COUNTY AND SOME OF
THESE COULD MOVE ONTO THE ADJACENT FRONT RANGE. MEANWHILE THERE
CONTINUES TO BE A WIDE RANGE OF MODEL SOLUTIONS EVEN FOR THE
PRECIPITATION IN THE NEXT 6 TO 12 HOURS. THE 12Z GFS HAD THE MOST
ORGANIZED WIDESPREAD HEAVY RAIN AREA AS IT ORGANIZED ONE OF THE
ABOVE NOTED FEATURES INTO A COMPACT CIRCULATION AT 700 MB. OTHER
MODELS KEEP MOST OF THE PRECIP MUCH FARTHER TO THE SOUTH. LATEST
HRRR HAS A WAVE OF PRECIP NEXT FEW HOURS THEN STAYS FARTHER SOUTH.
SOMETHING IN BETWEEN THE EXTREMES LOOKS MOST LIKELY AND KEPT
HIGHEST POPS OVER THE PALMER DIVIDE AND FAR EASTERN ZONES
LINGERING INTO THURSDAY MORNING.
LONG TERM...BACK EDGE OF MID LEVEL TROUGH TO BE EXITING EASTERN
COLORADO DURING THE EVENING WITH WEAK SUBSIDENCE SPREADING ACROSS
THE AREA. FLOW ALOFT APPEARS A BIT SPLIT WITH WESTERLY FLOW ACROSS
SOUTHERN COLORADO AND NORTHWEST FLOW ALOFT OVER NORTHERN
COLORADO...WITH THE MAIN BATCH OF SUBTROPICAL MOISTURE TO THE WEST
AND SOUTH OF THE CFWA. STILL ENOUGH MOISTURE AND WEAK INSTABILITY
DURING THE EVENING FOR SOME THUNDERSTORMS WHILE AIRMASS A BIT MORE
STABLE OVER PLAINS. SHOULD SEE STORMS END ACROSS PLAINS AROUND
MIDNIGHT AS AIRMASS CONTINUES TO STABILIZE WITH PERHAPS A FEW
STORMS LINGERING OVERNIGHT ACROSS THE HIGH COUNTRY. ON
FRIDAY...FLOW ALOFT BECOMES MORE WESTERLY BY THE AFTERNOON AS
MODEL CONSENSUS SHOWS A WEAK UPPER TROUGH MOVES ACROSS NORTHERN
WYOMING. HOWEVER...700 MB LOW IS STILL MORE SOUTHWEST...WHICH
SHOULD ALLOW SOME INCREASE IN SUBTROPICAL MOISTURE OVER THE AREA.
SURFACE HIGH TO PUSH ACROSS INTO CENTRAL PLAINS WITH LOW LEVEL
FLOW BECOMING SOUTHEAST BY THE AFTERNOON. THIS WILL ALLOW SOME
INCREASE IN LOW LEVEL MOISTURE ALONG WITH SLIGHTLY COOLER
TEMPERATURES. FORECAST SOUNDINGS SHOW A BIT OF A CAP ACROSS THE
PLAINS. SO BEST CHANCE FOR THUNDERSTORMS TO OCCUR ACROSS THE
MOUNTAINS AND FOOTHILLS DURING THE AFTERNOON AND EVENING WITH MOST
STORMS ENDING AROUND MIDNIGHT. ON SATURDAY...SOUTHWEST FLOW ALOFT
TO PREVAIL WITH SOME INCREASE IN SUBTROPICAL MOISTURE...WHICH
SHOULD LEAD TO A CHANCE OF THUNDERSTORMS OVER THE HIGH COUNTRY.
ACROSS PLAINS...AIRMASS STILL FAIRLY CAPPED AS NOTED BY FORECAST
SOUNDINGS WHICH SHOULD LIMIT THUNDERSTORM DEVELOPMENT. SOUTHEAST
SURFACE WINDS OVER EASTERN COLORADO TO PREVAIL BY THE THE
AFTERNOON WITH SOME HINTS OF A DENVER CYCLONE WHICH MAY INCREASE
STORM CHANCES EAST AND SOUTH OF DENVER. TEMPERATURES TO WARM IN
THE LOWER 80S ACROSS THE PLAINS. FOR SUNDAY...SOUTHWEST FLOW ALOFT
TO CONTINUE WITH WEAK UPPER TROUGH MOVING ACROSS CENTRAL PLAINS.
MODELS SHOW WEAK FRONT MOVING ACROSS THE PLAINS BY THE AFTERNOON
WITH SOME INCREASE IN LOW LEVEL MOISTURE. HOWEVER THE BEST
INSTABILITY LOOKS TO BE EAST OF COLORADO. BEST CHANCE FOR
THUNDERSTORMS TO BE ACROSS MOUNTAINS WITH A SLIGHT CHANCE OVER THE
PLAINS. HIGHS ACROSS PLAINS LOOK TO BE IN THE LOWER 80S.
FOR THE LATER DAYS...MONDAY THROUGH WEDNESDAY: MODELS SHOW UPPER
LEVEL RIDGE BUILDING ACROSS COLORADO WITH A GRADUAL DECREASE IN
SUBTROPICAL MOISTURE. THIS TO LEAD TO A DECREASING CHANCE OF
THUNDERSTORMS AND SLIGHTLY WARMER TEMPERATURES.
AVIATION...WEAK WIND SHIFT WENT BY DIA EARLIER BUT OTHERWISE A
GENERAL SOUTHEAST FLOW EXPECTED UNTIL LATER IN THE EVENING. MOST
IF NOT ALL THUNDERSTORMS SHOULD REMAIN SOUTH AND EAST OF THE
AIRPORT AS IT LOOKS NOW.
HYDROLOGY...GIVEN THE DEVELOPMENT TO OUR SOUTH AS NOTED ABOVE
WITH PUB GETTING ALMOST AN INCH OF RAIN IN A SHORT TIME THE THREAT
OF FLASH FLOODING STILL IN PLACE SO CONTINUE THE WATCH FOR THE
PALMER DIVIDE REGION.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SZOKE
LONG TERM....D-L
AVIATION/UPDATE...GIMMESTAD/BARJENBRUCH
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1119 PM MDT MON AUG 5 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 244 PM MDT MON AUG 5 2013
ACTIVE DAY FOR THE WESTERN SLOPES TODAY AS THUNDERSTORMS FIRED UP
EARLIER THAN PAST COUPLE DAYS WITHIN THE MONSOON PLUME. THIS IS OUT
AHEAD OF LEADING DISTURBANCE MOVING THROUGH SOUTHERN AZ.
MEANWHILE...ANOTHER DISTURBANCE IS EXITING EASTERN CO TO THE EAST.
DEW POINTS HAVE BEEN FALLING OFF ACROSS THE SE MTS/I-25 CORRIDOR AS
PROGGED BY MODELS WITH 40 DEW POINTS AND EVEN SOME UPPER 30S. EVEN
OUT TOWARDS LA JUNTA AND LAMAR...DEW POINTS HAVE BEEN FALLING INTO
THE LOWER 50S AS WINDS HAVE SHIFTED OUT OF THE SOUTH AND EVEN
SOUTHWEST AS THE SFC LOW HAS BEEN KICKING EASTWARD.
FOR THE REMAINDER OF THIS EVENING...SCATTERED THUNDERSTORMS EXPECTED
ACROSS THE MOUNTAINS...WITH HRRR SUGGESTING THUNDERSTORMS WILL
SPREAD INTO THE ADJACENT PLAINS DURING THE LATE AFTERNOON/EARLY
EVENING. NOT AS MUCH CAPE TODAY...SO NOT EXPECTING ANY STRONG
STORMS ALONG THE I-25 CORRIDOR. WRF WAS HITTING WALDO BURN SCAR BETWEEN 3-5
PM...WHILE EACH SUCCESSIVE RUN OF THE HRRR HAS BEN DELAYING THIS
POTENTIAL UNTIL A NORTHERLY SURGE AIDED BY CONVECTION ACROSS NE CO
DROPS INTO THE PIKES PEAK REGION JUST AS WEAK FORCING ENHANCING WRN
CO CONVECTION WORKS ITS WAY EASTWARD ACROSS THE SE MTS. THIS PUTS
TIME FRAME FOR WALDO TO GET HIT BETWEEN 6PM-8PM WHICH MAY BE A LITTLE
DELAYED FROM BEST SFC BASED HEATING TO REALIZE STRONG CONVECTION AND
HIGH RAINFALL RATES. BUT THIS WILL HAVE TO BE MONITORED CLOSELY.
OTHER AREA OF CONCERN BESIDES WILL BE OUT WEST ACROSS THE PAPOOSE
AND WEST FORK BURN SCARS WHERE THEY WILL BE UNDER THE GUN FROM
STORMS AND HEAVY RAINFALL/POTENTIAL FLASH FLOODING UNTIL 8 PM.
MEANWHILE...FAR SOUTHEAST PLAINS WILL HAVE TO BE WATCHED CLOSELY AS
CONVECTION ACROSS NW KS SENDS A BOUNDARY SOUTHWESTWARD INTO SE
CO...INCREASING SFC DEW POINTS. COULD SEE SOME THUNDERSTORMS
DEVELOP ALONG THE LEADING EDGE OF THIS OUTFLOW ACROSS
KIOWA...PROWERS AND BACA COUNTIES WITH POTENTIAL FOR A STRONG STORM OR TWO.
MAIN THREAT WINDOW WILL BE DURING THE EVENING...WITH POTENTIAL FOR
NEAR SEVERE HAIL AND WIND. BEST SEVERE THREAT THOUGH APPEARS TO BE
JUST NORTH AND EAST OF THE AREA.
TONIGHT...LOTS OF MID/HIGH CLOUDINESS WILL KEEP TEMPERATURES ON THE
WARM SIDE...WITH POPS DIMINISHING FOR MOST AREAS BY MIDNIGHT. CAN`T
RULE OUT SOME ISOLATED SHOWERS AND THUNDERSTORMS OUT WEST WITHIN THE
MONSOON PLUME. ON TUESDAY...PERHAPS A BIT MORE ACTIVE OUT WEST AS
SHORTWAVES EMBEDDED IN MONSOON PLUME WORK THEIR WAY NORTHWARD
THROUGH AZ INTO SRN UT/FOUR CORNERS REGION TOWARDS 00Z.
CONTEMPLATED GOING WITH A FLASH FLOOD WATCH FOR THE WEST FORK AND
PAPOOSE BURN SCARS TOMORROW...BUT SFC DEW POINTS DON`T APPEAR TO
MOISTEN ALL THAT MUCH...AND MODEL QPFS OFF THE LARGER SCALE MODELS
ARE NOT ALL THAT MUCH HIGHER. STILL THERE IS SOME INCREASE IN
PRECIP WATERS OUT THAT WAY...SO WILL HAVE TO MONITOR THIS
POTENTIAL. WILL LET LATER SHIFTS GET A LOOK AT THE HIGH RES SHORT
RANGE MODELS AS THEY START TO RESOLVE THAT PERIOD. OTHERWISE...FOR
THE EASTERN AREAS LOOKS LIKE MORE OF THE SAME. ANOTHER DAY OF LOWER
SFC DEW POINTS ACROSS THE PLAINS WHICH KEEPS LCLS ON THE HIGH SIDE.
STILL ENOUGH MOISTURE IN THE MONSOON PLUME FOR SOME LOCALLY HEAVY
RAIN WITH THE STRONGER STORMS...BUT FOR NOW THIS THREAT LOOKS TOO
LOCALIZED TO WARRANT ANY FLASH FLOOD WATCHES FOR THE WALDO OR BLACK
FOREST. THIS COULD CHANGE INTO THE EVENING HOURS AS MODELS DROP A
FRONT REINFORCED BY THUNDERSTORM OUTFLOWS INTO THE AREA FROM NE CO.
-KT
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 244 PM MDT MON AUG 5 2013
...HEAVY RAIN EXPECTED ON WEDNESDAY...
HIGH PRESSURE OVER TEXAS AND AN AREA OF LOW PRESSURE OFF THE
NORTHERN CALIFORNIA COAST WILL FORCE SOUTHERLY MONSOON ENERGY
ACROSS COLORADO THROUGH THURSDAY. THIS WILL SET THE STAGE FOR
WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY TUESDAY NIGHT THROUGH
THURSDAY AFTERNOON.
EXPECT ACTIVE SHOWER AND THUNDERSTORM ACTIVITY TUESDAY EVENING
OVER THE MOUNTAINS AND SPREADING INTO THE PLAINS. LOCALLY HEAVY
RAINFALL WILL BE POSSIBLE DURING THIS TIME PERIOD. MODELS
INDICATING A SMALL LULL AROUND MIDNIGHT BEFORE ACTIVITY INCREASES
AGAIN HEADING INTO WEDNESDAY MORNING. HOW QUICKLY THINGS PICK LATE
TUESDAY NIGHT/WEDNESDAY MORNING WILL DEPEND ON HOW FAST A FRONT
MOVES SOUTH ACROSS THE AREA...AND A STRONG SHORTWAVE EJECTS
NORTHEAST OUT OF THE DESERT SOUTHWEST. FRONTAL TIMING LOOKS TO
IMPACT THE AREA BY WEDNESDAY MORNING WITH A VERY MOIST AIR MASS
MOVING INTO THE PLAINS BEHIND THE FRONT. IN ADDITION...LOW LEVEL
FLOW IS FORECAST TO TURN EASTERLY WITH GOOD UPSLOPE FLOW ACROSS
THE PLAINS. ALL OF THESE LOW LEVEL FEATURES WILL COMBINE WITH A
VERY STRONG SHORTWAVE TROUGH ACROSS COLORADO TO PRODUCE WIDESPREAD
MODERATE TO HEAVY RAINFALL ACROSS THE AREA. IN ADDITION...COLDER
AIR ALOFT WILL MOVE INTO THE AREA WHICH WILL LIKELY INCREASE LAPSE
RATES AND INSTABILITY ACROSS COLORADO. THE AREA OF GREATEST
CONCERN WILL BE THE EASTERN MOUNTAINS AND I-25 CORRIDOR. MODELS
ARE INDICATING WELL OVER AN INCH OF PRECIPITATION WILL BE
POSSIBLE...ESPECIALLY IF WE CAN GET ENHANCEMENT FROM CONVECTIVE
UPDRAFTS. THE ONE CAVEAT MAY BE CLOUD COVER ACROSS THE PLAINS
WHICH WOULD LIMIT INSTABILITY AND CONVECTIVE ENHANCEMENT. THIS
WILL NEED TO BE WATCHED. FLASH FLOODING WILL BE OF GREAT
CONCERN...ESPECIALLY FOR AREA BURN SCARS. EXTREME CAUTION IS
ADVISED AND FOLKS SHOULD REMAIN COGNIZANT OF THE WEATHER AROUND
THEM. THE UPPER SYSTEM WILL BE SLOW TO MOVE OUT...WITH THE
MODERATE TO HEAVY RAINFALL SLOWLY MOVING EAST ACROSS THE PLAINS
WEDNESDAY NIGHT.
THURSDAY...MOISTURE WILL BE IN PLACE AND DEPARTING UPPER LEVEL
ENERGY WILL LIKELY LEAD TO SHOWERS AND THUNDERSTORMS DEVELOPING
OVER THE MOUNTAINS THURSDAY AFTERNOON. LOCALLY HEAVY RAINFALL WILL
BE POSSIBLE...AND FLASH FLOODING WILL BE POSSIBLE OVER AREA BURN
SCARS. IF TRENDS HAVE ANYTHING TO SAY ABOUT IT...THE DAY AFTER
EXPECTED WIDESPREAD HEAVY RAINFALL EVENTS SEEM TO BE PRIMED FOR
HEAVIER RAINFALL OUT OF THUNDERSTORMS THAN MODELS SEEM TO
INDICATE.
THE PATTERN BEGINS TO SHIFT FRIDAY INTO EARLY NEXT WEEK. THE LOW
OFF NORTHERN CALIFORNIA WILL DRIFT NORTHWARD HAS HIGH PRESSURE
OVER TEXAS BUILDS NORTH ACROSS COLORADO. THE MAIN MONSOONAL TAP
SHIFTS WESTWARD INTO THE GREAT BASIN. MODELS ARE INDICATING A
DOWNWARD TREND IN CONVECTIVE ACTIVITY THROUGH THE WEEKEND WITH
SHOWER AND THUNDERSTORM ACTIVITY REMAINING CONFINED TO MOUNTAIN
AREAS. MOZLEY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1117 PM MDT MON AUG 5 2013
VFR CONDITIONS ARE EXPECTED OVER THE KALS...KCOS AND KPUB TAF
SITES FROM TONIGHT INTO TUESDAY AFTERNOON.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
928 PM EDT WED AUG 7 2013
.SYNOPSIS...
A WEAK WARM FRONT WILL APPROACH AND LIFT NORTHWARD THROUGH THE
REGION TONIGHT THROUGH THURSDAY. LOW PRESSURE MOVING ACROSS
SOUTHEASTERN CANADA WILL ALLOW A COLD FRONT TO SLOWLY APPROACH OUR
REGION FROM THE WEST FOR THE END OF THE WORK WEEK. THE FRONT IS
EXPECTED TO CROSS OUR AREA DURING SATURDAY AND EVENTUALLY STALL TO
OUR SOUTH FOR SUNDAY. EARLY NEXT WEEK, A FEW WAVES OF LOW PRESSURE
ARE FORECAST TO MOVE ALONG THE STALLED BOUNDARY, FOLLOWED BY HIGH
PRESSURE BUILDING TOWARD THE REGION FOR MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
NOT MUCH CHANGE WITH THE 930PM UPDATE AS THE TEMPERATURES AND
DEWPOINTS ARE ON TRACK AS ARE THE POPS. DID EDGE THE LIKELY POPS
FURTHER SOUTH THAN PREVIOUSLY FORECASTED AS SOME OF THE HEAVIER
RAIN HAS SPREAD INTO CENTRAL MARYLAND. OTHERWISE EVERYTHING ELSE
APPEARS TO BE ON TRACK.
THE TREND IS FOR SOME WEAKENING OF THE STORMS TO OUR WEST SO NOT
EXPECTING ANYTHING SEVERE TO OCCUR. THE LATEST RUC SEEMS TO HAVE A
DECENT HANDLE ON THE PLACEMENT AND MOVEMENT OF THE SHORTWAVE AND
ITS SHOWERS CARRYING THEM INTO OUR WEST AND NORTH ZONES AFTER 3Z.
DISCRETE CELLS ARE ALSO FIRING AHEAD OF THE LINE OF STORMS TO THE
WEST OF SELINSGROVE DOWN TO ALTOONA, WHERE THE BEST ML- MUCAPES
REMAINS. THESE ARE TAKING MORE OF A SOUTHWEST TO NORTHEAST
MOVEMENT AND MAY CLIP OUR WESTERN ZONES OVER THE NEXT HOUR OR TWO.
THOUGH WE ARE STARTING TO SEE SOME THINNING OF THE CLOUDS FROM THE
SOUTHWEST, WHERE BETTER MIXING HAS OCCURRED FOR MOST OF THE DAY,
THERE IS STILL PLENTY THAT WILL TRY TO PUSH IN FROM THE WEST-
NORTHWEST WITH THE SHORTWAVE. WE KEEP THE OVERCAST CONDITIONS
ACROSS A BETTER PART OF THE REGION TONIGHT AND CEILINGS SHOULD
BEGIN TO LOWER A BIT MORE TOO. AS FOR OVERNIGHT LOWS WE CAN ONLY
BE WRONG SO MUCH AS DEW POINTS HAVE RISEN AND WE CAN ONLY GO SO
LOW.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THE FOCUS ON THURSDAY FOR SHOWERS AND THUNDERSTORMS WITH HEAVIER
RAIN SHIFTS TO THE NORTHWEST OF OUR CWA. AS ONE OF OUR COLLEGE
VOLUNTEERS SHOWED IN THE BRIEFING THE GREATEST INSTABILITY IS
FORECAST TO BE THERE CLOSER TO THE DEPARTING WARM FRONT AS WELL AS
MORE ENTRENCHED IN THE 925MB/850MB DEEPER MOISTURE POOL COMING FROM
THE OHIO VALLEY AND SLIGHTLY COLDER AIR AT THE MID LEVELS. ITS ALSO
THE LOCATION CLOSEST TO THE FCST MID LEVEL QVEC CONVERGENCE (BETTER
NORTH OF OUR AREA) THE FORECAST BULK SHEAR IS NOT AS VIGOROUS AS IT
IS TODAY AND MID LEVEL LAPSE RATES ARE MODERATE AT BEST. SO THERE
COULD BE SOME CLOSE TO SEVERE STORMS NORTHWEST DEPENDING UPON
TIMING. FCST DCAPES AND DROP OF THETA E WITH HEIGHT DONT SUPPORT
PULSE TYPE SEVERE, SO SOME ORGANIZATION POOLING WILL BE NEEDED FOR
THE STORMS TO BECOME STRONGER. WITH PWATS CONTINUING TO RISE THE
THREAT FOR HEAVY RAIN ALSO CONTINUES AND IN FACT INTENSIFIES.
WE SHOULD BE STARTING CLOUDY DURING THE MORNING, BUT WE ARE
EXPECTING ENOUGH SUNSHINE TO DEVELOP TO GET TO STAT GUIDANCE HIGHS
(AS WELL AS TRIGGER CONVECTION). LOWEST CONFIDENCE ABOUT OUR MAX
TEMPS IS NORTH BECAUSE OF THE WARM FRONTAL POSITION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
UNSETTLED WEATHER IS EXPECTED THROUGH MUCH OF THE LONG TERM PERIOD,
AS A SLOW-MOVING COLD FRONT APPROACHES FROM THE WEST AND EVENTUALLY
STALLS TO OUR SOUTH. ALOFT, A MAINLY ZONAL FLOW WILL BE IN PLACE,
WITH SOME SLIGHT TROUGHING LATE THIS WEEKEND INTO EARLY NEXT WEEK.
BOTH THE GFS AND ECMWF SHOW MULTIPLE SHORTWAVES AND VORT MAXES
MOVING THROUGH THIS MAINLY ZONAL FLOW ACROSS OUR REGION THROUGH
EARLY NEXT WEEK. MEANWHILE, THE SURFACE COLD FRONT WILL GRADUALLY
APPROACH OUR AREA FROM THE WEST DURING FRIDAY, EVENTUALLY
PROGRESSING SOUTH AND EAST OF THE REGION BY THE END OF THE WEEKEND.
THIS PATTERN AT THE SURFACE AND ALOFT WILL KEEP SCATTERED
SHWRS/TSTORMS IN THE PICTURE, ESPECIALLY FOR OUR SOUTHERN ZONES.
WITH THE STALLED FRONTAL BOUNDARY REMAINING TO OUR SOUTH INTO THE
MONDAY AND TUESDAY TIMEFRAME, ISOLATED CONVECTION MAY STILL BE A
POSSIBILITY FOR OUR DELMARVA ZONES AS MODEL GUIDANCE SHOWS A FEW
WAVES OF LOW PRESSURE MOVING ALONG THE BOUNDARY. BOTH THE ECMWF AND
GFS SHOW HIGH PRESSURE TRYING TO BUILD INTO THE REGION BY MID-WEEK
AND EVENTUALLY PUSHING THE STALLED FRONTAL BOUNDARY FARTHER SOUTH,
BUT CONFIDENCE IS ONLY AVERAGE REGARDING THE TIMING AND PROGRESSION
OF THESE FEATURES AT THIS EXTENDED TIME RANGE.
AHEAD OF THE APPROACHING COLD FRONT ON FRIDAY, PWATS ARE EXPECTED TO
CLIMB INTO THE 1.5 TO 2 INCH RANGE ACROSS THE REGION, AND THIS
AVAILABLE MOISTURE WILL PERSIST INTO THE WEEKEND. THIS COMBINED WITH
ONLY A MODEST FLOW ALOFT WILL KEEP THE POTENTIAL FOR HEAVY RAIN IN
THE PICTURE WITH FLOODING OF POOR DRAINAGE AND LOW LYING AREAS BEING
A CONTINUED CONCERN. BY THE MIDDLE OF NEXT WEEK, WITH AN AREA OF
HIGH PRESSURE PROGGED TO EDGE INTO OUR REGION FROM THE NORTHWEST,
THE STALLED FRONTAL BOUNDARY WILL GRADUALLY BE PUSHED FARTHER SOUTH,
ALLOWING FOR SOME DRIER AIR TO ADVANCE INTO THE REGION.
OVERALL, NEAR TO SLIGHTLY ABOVE AVERAGE DAYTIME TEMPERATURES ARE
EXPECTED FOR THE REGION THROUGH THE WEEKEND, WITH HIGHS REACHING
FROM THE UPPER 70S ACROSS THE SOUTHERN POCONOS TO THE UPPER 80S FOR
OUR SOUTHERN ZONES. BY THE MIDDLE OF NEXT WEEK, DAYTIME TEMPERATURES
SHOULD RETURN CLOSER TO OR EVEN A BIT BELOW AVERAGE AS HIGH PRESSURE
BUILDS DOWN FROM THE NORTHWEST, WITH HIGHS RANGING FROM THE LOW TO
MID 70S NORTH TO THE LOWER 80S SOUTH.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THIS IS NOT A CONFIDENT FORECAST THROUGH THE NEXT 12 HOURS GIVEN
POCKETS OF DRY AIR ALOFT TRYING TO SQUEEZE INTO THE REGION FROM
THE SOUTHWEST MAKING THE CIGS JUMP AROUND A BIT.
FOR TONIGHT, WE SHOULD REMAIN PRIMARILY MVFR OUTSIDE OF MIV/ACY,
WITH AREAS OF SHOWERS AND POSSIBLE A COUPLE RUMBLES OF THUNDER
MOVING THROUGH FOR THE NEXT COUPLE OF HOURS. TEMPO GROUPS HAVE BEEN
PLACED IN THE TAFS FOR SUCH OCCURRENCES. TERMINALS THAT RECEIVE A
BIT MORE RAIN TONIGHT HAVE A BETTER CHANCE AT SEEING IFR CIGS
DEVELOP BY MID-MORNING, OR AT LEAST LOW-MVFR. AGAIN NOT TOO
CONFIDENT ON HOW WIDESPREAD THE IFR CIGS WILL BE.
ON THURSDAY WE ARE EXPECTING CONDITIONS TO IMPROVE TO VFR, WITH
GREATER CONFIDENCE AS THE MORNING PROGRESSES AND LIKELY FASTER
IMPROVEMENT SOUTHERN TERMINALS, AIRPORTS VS THE NORTHERN ONES.
THERE WILL BE A GREATER CHANCE FOR THUNDERSTORMS VS TODAY, WHICH
SHOULD BE MAINLY AFTER 18Z. PROB30S HAVE BEEN PLACED AT A MAJORITY
OF OUR TAFS TO ACCOUNT FOR THE AFTERNOON STORMS THOUGH TIMING
STILL NEEDS TO BE TWEAKED.
OUTLOOK...
THURSDAY NIGHT THROUGH EARLY MORNING SATURDAY...MAINLY MVFR
CONDITIONS EXPECTED. POTENTIAL FOR LOWER CONDITIONS AT TIMES IN
HEAVIER SHOWERS AND TSTORMS.
REMAINDER OF SATURDAY THROUGH MONDAY...MOSTLY VFR CONDITIONS.
ISOLATED SHWRS/TSTORMS REMAIN POSSIBLE.
&&
.MARINE...
SUB SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED THROUGH THURSDAY.
THE STRONGEST WINDS HAVE BEEN NEAR THE IMMEDIATE COAST. WAVE WATCH
MODEL IS ABOUT TO START RUNNING ABOUT A FOOT TOO HIGH. IN GENERAL A
SOUTHERLY FLOW OF AIR IS EXPECTED TO PREVAIL THROUGH THURSDAY AS OUR
FORECAST AREA GETS DEEPER INTO THE WARM SECTOR ON THE OTHER SIDE OF
THE WARM FRONT. THUS GUIDANCE WINDS SHOULD BE A BIT ON THE HIGH SIDE
AND WE CAPPED SEAS ABOUT A FOOT BELOW WAVE WATCH GUIDANCE.
OUTLOOK...
OVERALL, SUB-SCA CONDITIONS ARE EXPECTED FOR OUR AREA WATERS THROUGH
THE BULK OF THE OUTLOOK PERIOD. GUIDANCE IS SHOWING AN INCREASE IN
THE SOUTHERLY TO SOUTHWESTERLY FLOW DURING FRIDAY AHEAD OF AN
APPROACHING COLD FRONT. SOME WIND GUSTS AROUND 20 KNOTS ARE EXPECTED
FRIDAY INTO FRIDAY NIGHT. IN ADDITION, WAVEWATCH GUIDANCE ALSO
INDICATES SEAS RISING TO AROUND 5 FEET FOR OUR COASTAL WATERS DURING
THIS TIMEFRAME. HOWEVER, THIS GUIDANCE TENDS TO RUN A LITTLE HIGH IN
SOUTHERLY FLOW, AND CONFIDENCE IS BELOW AVERAGE AT THIS TIME FOR
SEAS REACHING 5 FEET BEFORE THE FRONTAL BOUNDARY MOVES THROUGH AND
WINDS BECOME MORE WEST AND THEN NORTHWEST OVER THE WEEKEND.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...GIGI/HEAVENER
SHORT TERM...GIGI
LONG TERM...KLINE
AVIATION...GIGI/HEAVENER/KLINE
MARINE...GIGI/KLINE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
816 PM EDT WED AUG 7 2013
.SYNOPSIS...
A WEAK WARM FRONT WILL APPROACH AND LIFT NORTHWARD THROUGH THE
REGION TONIGHT THROUGH THURSDAY. LOW PRESSURE MOVING ACROSS
SOUTHEASTERN CANADA WILL ALLOW A COLD FRONT TO SLOWLY APPROACH OUR
REGION FROM THE WEST FOR THE END OF THE WORK WEEK. THE FRONT IS
EXPECTED TO CROSS OUR AREA DURING SATURDAY AND EVENTUALLY STALL TO
OUR SOUTH FOR SUNDAY. EARLY NEXT WEEK, A FEW WAVES OF LOW PRESSURE
ARE FORECAST TO MOVE ALONG THE STALLED BOUNDARY, FOLLOWED BY HIGH
PRESSURE BUILDING TOWARD THE REGION FOR MID-WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WE MAINTAIN THE CURRENT POPS ACROSS OUR NORTHERN ZONES AS THE
STRONGEST OF MID-LEVEL SHORTWAVES CONTINUES TO SPARK HEAVY SHOWERS
AND THUNDERSTORMS ACROSS CENTRAL PENNSYLVANIA. THE TREND IS FOR
SOME WEAKENING, SO NOT EXPECTING ANYTHING SEVERE TO OCCUR. THE
LATEST RUC SEEMS TO HAVE A DECENT HANDLE ON THE PLACEMENT AND
MOVEMENT OF THE SHORTWAVE AND ITS SHOWERS CARRYING THEM INTO OUR
WEST AND NORTH ZONES AFTER 3Z. DISCRETE CELLS ARE ALSO FIRING
AHEAD OF THE LINE OF STORMS TO THE WEST OF SELINSGROVE DOWN TO
ALTOONA, WHERE THE BEST ML- MUCAPES REMAINS. THESE ARE TAKING MORE
OF A SOUTHWEST TO NORTHEAST MOVEMENT AND MAY CLIP OUR WESTERN
ZONES OVER THE NEXT HOUR OR TWO.
THOUGH WE ARE STARTING TO SEE SOME THINNING OF THE CLOUDS FROM THE
SOUTHWEST, WHERE BETTER MIXING HAS OCCURED FOR MOST OF THE DAY,
THERE IS STILL PLENTY THAT WILL TRY TO PUSH IN FROM THE WEST-
NORTHWEST WITH THE SHORTWAVE. WE KEEP THE OVERCAST CONDITIONS
ACROSS A BETTER PART OF THE REGION TONIGHT AND CEILINGS SHOULD
BEGIN TO LOWER A BIT MORE TOO. AS FOR OVERNIGHT LOWS WE CAN ONLY
BE WRONG SO MUCH AS DEW POINTS HAVE RISEN AND WE CAN ONLY GO SO
LOW.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THE FOCUS ON THURSDAY FOR SHOWERS AND THUNDERSTORMS WITH HEAVIER
RAIN SHIFTS TO THE NORTHWEST OF OUR CWA. AS ONE OF OUR COLLEGE
VOLUNTEERS SHOWED IN THE BRIEFING THE GREATEST INSTABILITY IS
FORECAST TO BE THERE CLOSER TO THE DEPARTING WARM FRONT AS WELL AS
MORE ENTRENCHED IN THE 925MB/850MB DEEPER MOISTURE POOL COMING FROM
THE OHIO VALLEY AND SLIGHTLY COLDER AIR AT THE MID LEVELS. ITS ALSO
THE LOCATION CLOSEST TO THE FCST MID LEVEL QVEC CONVERGENCE (BETTER
NORTH OF OUR AREA) THE FORECAST BULK SHEAR IS NOT AS VIGOROUS AS IT
IS TODAY AND MID LEVEL LAPSE RATES ARE MODERATE AT BEST. SO THERE
COULD BE SOME CLOSE TO SEVERE STORMS NORTHWEST DEPENDING UPON
TIMING. FCST DCAPES AND DROP OF THETA E WITH HEIGHT DONT SUPPORT
PULSE TYPE SEVERE, SO SOME ORGANIZATION POOLING WILL BE NEEDED FOR
THE STORMS TO BECOME STRONGER. WITH PWATS CONTINUING TO RISE THE
THREAT FOR HEAVY RAIN ALSO CONTINUES AND IN FACT INTENSIFIES.
WE SHOULD BE STARTING CLOUDY DURING THE MORNING, BUT WE ARE
EXPECTING ENOUGH SUNSHINE TO DEVELOP TO GET TO STAT GUIDANCE HIGHS
(AS WELL AS TRIGGER CONVECTION). LOWEST CONFIDENCE ABOUT OUR MAX
TEMPS IS NORTH BECAUSE OF THE WARM FRONTAL POSITION.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
UNSETTLED WEATHER IS EXPECTED THROUGH MUCH OF THE LONG TERM PERIOD,
AS A SLOW-MOVING COLD FRONT APPROACHES FROM THE WEST AND EVENTUALLY
STALLS TO OUR SOUTH. ALOFT, A MAINLY ZONAL FLOW WILL BE IN PLACE,
WITH SOME SLIGHT TROUGHING LATE THIS WEEKEND INTO EARLY NEXT WEEK.
BOTH THE GFS AND ECMWF SHOW MULTIPLE SHORTWAVES AND VORT MAXES
MOVING THROUGH THIS MAINLY ZONAL FLOW ACROSS OUR REGION THROUGH
EARLY NEXT WEEK. MEANWHILE, THE SURFACE COLD FRONT WILL GRADUALLY
APPROACH OUR AREA FROM THE WEST DURING FRIDAY, EVENTUALLY
PROGRESSING SOUTH AND EAST OF THE REGION BY THE END OF THE WEEKEND.
THIS PATTERN AT THE SURFACE AND ALOFT WILL KEEP SCATTERED
SHWRS/TSTORMS IN THE PICTURE, ESPECIALLY FOR OUR SOUTHERN ZONES.
WITH THE STALLED FRONTAL BOUNDARY REMAINING TO OUR SOUTH INTO THE
MONDAY AND TUESDAY TIMEFRAME, ISOLATED CONVECTION MAY STILL BE A
POSSIBILITY FOR OUR DELMARVA ZONES AS MODEL GUIDANCE SHOWS A FEW
WAVES OF LOW PRESSURE MOVING ALONG THE BOUNDARY. BOTH THE ECMWF AND
GFS SHOW HIGH PRESSURE TRYING TO BUILD INTO THE REGION BY MID-WEEK
AND EVENTUALLY PUSHING THE STALLED FRONTAL BOUNDARY FARTHER SOUTH,
BUT CONFIDENCE IS ONLY AVERAGE REGARDING THE TIMING AND PROGRESSION
OF THESE FEATURES AT THIS EXTENDED TIME RANGE.
AHEAD OF THE APPROACHING COLD FRONT ON FRIDAY, PWATS ARE EXPECTED TO
CLIMB INTO THE 1.5 TO 2 INCH RANGE ACROSS THE REGION, AND THIS
AVAILABLE MOISTURE WILL PERSIST INTO THE WEEKEND. THIS COMBINED WITH
ONLY A MODEST FLOW ALOFT WILL KEEP THE POTENTIAL FOR HEAVY RAIN IN
THE PICTURE WITH FLOODING OF POOR DRAINAGE AND LOW LYING AREAS BEING
A CONTINUED CONCERN. BY THE MIDDLE OF NEXT WEEK, WITH AN AREA OF
HIGH PRESSURE PROGGED TO EDGE INTO OUR REGION FROM THE NORTHWEST,
THE STALLED FRONTAL BOUNDARY WILL GRADUALLY BE PUSHED FARTHER SOUTH,
ALLOWING FOR SOME DRIER AIR TO ADVANCE INTO THE REGION.
OVERALL, NEAR TO SLIGHTLY ABOVE AVERAGE DAYTIME TEMPERATURES ARE
EXPECTED FOR THE REGION THROUGH THE WEEKEND, WITH HIGHS REACHING
FROM THE UPPER 70S ACROSS THE SOUTHERN POCONOS TO THE UPPER 80S FOR
OUR SOUTHERN ZONES. BY THE MIDDLE OF NEXT WEEK, DAYTIME TEMPERATURES
SHOULD RETURN CLOSER TO OR EVEN A BIT BELOW AVERAGE AS HIGH PRESSURE
BUILDS DOWN FROM THE NORTHWEST, WITH HIGHS RANGING FROM THE LOW TO
MID 70S NORTH TO THE LOWER 80S SOUTH.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THIS IS NOT A CONFIDENT FORECAST THROUGH THE NEXT 12 HOURS GIVEN
POCKETS OF DRY AIR ALOFT TRYING TO SQUEEZE INTO THE REGION FROM
THE SOUTHWEST MAKING THE CIGS JUMP AROUND A BIT.
FOR TONIGHT, WE SHOULD REMAIN PRIMARILY MVFR OUTSIDE OF MIV/ACY,
WITH AREAS OF SHOWERS AND POSSIBLE A COUPLE RUMBLES OF THUNDER
MOVING THROUGH FOR THE NEXT COUPLE OF HOURS. TEMPO GROUPS HAVE BEEN
PLACED IN THE TAFS FOR SUCH OCCURRENCES. TERMINALS THAT RECEIVE A
BIT MORE RAIN TONIGHT HAVE A BETTER CHANCE AT SEEING IFR CIGS
DEVELOP BY MID-MORNING, OR AT LEAST LOW-MVFR. AGAIN NOT TOO
CONFIDENT ON HOW WIDESPREAD THE IFR CIGS WILL BE.
ON THURSDAY WE ARE EXPECTING CONDITIONS TO IMPROVE TO VFR, WITH
GREATER CONFIDENCE AS THE MORNING PROGRESSES AND LIKELY FASTER
IMPROVEMENT SOUTHERN TERMINALS, AIRPORTS VS THE NORTHERN ONES.
THERE WILL BE A GREATER CHANCE FOR THUNDERSTORMS VS TODAY, WHICH
SHOULD BE MAINLY AFTER 18Z. PROB30S HAVE BEEN PLACED AT A MAJORITY
OF OUR TAFS TO ACCOUNT FOR THE AFTERNOON STORMS THOUGH TIMING
STILL NEEDS TO BE TWEAKED.
OUTLOOK...
THURSDAY NIGHT THROUGH EARLY MORNING SATURDAY...MAINLY MVFR
CONDITIONS EXPECTED. POTENTIAL FOR LOWER CONDITIONS AT TIMES IN
HEAVIER SHOWERS AND TSTORMS.
REMAINDER OF SATURDAY THROUGH MONDAY...MOSTLY VFR CONDITIONS.
ISOLATED SHWRS/TSTORMS REMAIN POSSIBLE.
&&
.MARINE...
SUB SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED THROUGH THURSDAY.
THE STRONGEST WINDS HAVE BEEN NEAR THE IMMEDIATE COAST. WAVE WATCH
MODEL IS ABOUT TO START RUNNING ABOUT A FOOT TOO HIGH. IN GENERAL A
SOUTHERLY FLOW OF AIR IS EXPECTED TO PREVAIL THROUGH THURSDAY AS OUR
FORECAST AREA GETS DEEPER INTO THE WARM SECTOR ON THE OTHER SIDE OF
THE WARM FRONT. THUS GUIDANCE WINDS SHOULD BE A BIT ON THE HIGH SIDE
AND WE CAPPED SEAS ABOUT A FOOT BELOW WAVE WATCH GUIDANCE.
OUTLOOK...
OVERALL, SUB-SCA CONDITIONS ARE EXPECTED FOR OUR AREA WATERS THROUGH
THE BULK OF THE OUTLOOK PERIOD. GUIDANCE IS SHOWING AN INCREASE IN
THE SOUTHERLY TO SOUTHWESTERLY FLOW DURING FRIDAY AHEAD OF AN
APPROACHING COLD FRONT. SOME WIND GUSTS AROUND 20 KNOTS ARE EXPECTED
FRIDAY INTO FRIDAY NIGHT. IN ADDITION, WAVEWATCH GUIDANCE ALSO
INDICATES SEAS RISING TO AROUND 5 FEET FOR OUR COASTAL WATERS DURING
THIS TIMEFRAME. HOWEVER, THIS GUIDANCE TENDS TO RUN A LITTLE HIGH IN
SOUTHERLY FLOW, AND CONFIDENCE IS BELOW AVERAGE AT THIS TIME FOR
SEAS REACHING 5 FEET BEFORE THE FRONTAL BOUNDARY MOVES THROUGH AND
WINDS BECOME MORE WEST AND THEN NORTHWEST OVER THE WEEKEND.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLINE
NEAR TERM...GIGI/HEAVENER
SHORT TERM...GIGI
LONG TERM...KLINE
AVIATION...GIGI/HEAVENER/KLINE
MARINE...GIGI/KLINE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
825 PM EDT WED AUG 7 2013
.DISCUSSION...
LATEST RUC ANALYSIS SHOWING THE ATLC RIDGE AXIS EXTENDING DOWN THE
ERN SEABOARD WITH THE AXIS ROUGHLY PARALLEL AND JUST N OF THE I-4
CORRIDOR. PENINSULA WSR-88D WIND PROFILERS SHOWING A STEADY E/SE
BREEZE THRU 4-5KFT...CONSISTENT WITH THE POSITION OF THE RIDGE. RUC
ANALYSIS SHOWING LITTLE IN THE WAY OF MID LVL VORTICITY UPSTREAM
COUPLED WITH FAIRLY STRONG SINKING OMEGA AIR. H100-H70 MEAN RH
VALUES BTWN 75-80PCT OVER THE LCL ATLC...DECREASING BLO 70PCT OVER
THE NRN/CENTRAL BAHAMAS. WEAK THERMODYNAMIC PROFILE OVERHEAD AS WELL
WITH MID LVL LAPSE RATES AOB 5.5C/KM...H70 TEMPS ARND 9C...AND H50
TEMPS ARND -6C.
DIURNAL CONVECTION HAS PUSHED W OF THE CWA...CONCENTRATING ALONG THE
W FL COAST WITH SOME RATHER ACTIVE TSRA CELLS OVER THE TAMPA BAY
AREA. UPSTREAM...ISOLD SHRAS DVLPG IN THE WAKE VORTICIES DOWNWIND OF
THE NRN BAHAMAS AS SHOWN LITTLE SHOREWARD DRIFT. FARTHER N ISOLD
SHRAS OFF THE FIRST COAST SHOWING MORE WRLY MOTION BUT NOT SURVIVING
LONG AS THEY DRIFT OUT OF THE WARMER GULF STREAM WATERS.
ANTICIPATE ONLY BRIEF ISOLD SHRA ACTIVITY OVER THE GULF STREAM
OVERNIGHT AS THE DRIER AND MORE STABLE UPSTREAM AIRMASS BEGINS TO
ADVECT W TOWARD THE FL PENINSULA. LCL NUMERICAL GUIDANCE INDICATING
OVERNIGHT POPS BLO 15PCT AREAWIDE...BLO 10PCT S OF KMLB...MOST OF
WHICH REFLECTS THE REMNANT OF TODAY`S CONVECTION. CAN SEE NO
MEANINGFUL CHANCE FOR COASTAL SHRAS OVERNIGHT. EVEN IF ONE OR TWO
WERE TO SURVIVE THE TREK ACRS THE COOLER SHELF WATERS...IMPACT WOULD
BE NEGLIGIBLE AND LIMITED TO THE IMMEDIATE COAST. WILL REMOVE PRECIP
FROM THE FCST WITH THE EVENING UPDATE.
&&
.AVIATION...
THRU 08/14Z...VFR ALL SITES...SE SFC WNDS DECREASING TO AOB 5KTS
INTERIOR...5-10KTS ALONG THE COAST. BTWN 08/14Z-08/17Z...E/SE SFC
WNDS INCREASING TO 12-15KTS WITH OCNL SFC G20KTS S OF KMLB. BTWN
08/17Z-08/23Z...SCT MVFR SHRAS/ISOLD IFR TSRAS NW OF KMLB-KOBE MVG
W/NW ARND 15KTS.
&&
.MARINE...
DATA BUOYS/C-MAN STATIONS MEASURING SERLY WINDS AOB 12KTS...SEAS
1-2FT NEARSHORE AND 2-3FT OFFSHORE. LITTLE CHANGE ANTICIPATED
OVERNIGHT WITH THE BROAD ATLC RIDGE AXIS REBUILDING ALONG THE I-4
CORRIDOR IN THE WAKE OF AN ERLY WAVE PUSHING INTO THE SE GOMEX. WILL
ADJUST SEAS DOWN ABOUT A FOOT AREAWIDE WITH THE EVENING UPDATE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
IMPACT WX...PENDERGRAST
AREA FORECAST DISCUSSION
NWS MIAMI FL
253 PM EDT TUE AUG 6 2013
.SHORT TERM (TONIGHT-THURSDAY NIGHT)...
A MID/UPPER LEVEL RIDGE CURRENTLY STRETCHES ACROSS THE SOUTHERN
STATES INTO THE ATLANTIC WITH AN INVERTED TROUGH MOVING WEST ACROSS
THE EASTERN BAHAMAS BENEATH THE RIDGE AXIS. AT THE SURFACE, A WEAK
SURFACE TROUGH EXTENDS FROM SOUTH FLORIDA INTO THE NORTHERN BAHAMAS
AND INTO THE CENTRAL ATLANTIC. THE SURFACE TROUGH IS A VERY SHALLOW
FEATURE AND THIS COMBINED WITH THE UPPER TROUGH TO THE EAST AND
RIDGE TO THE NORTH IS RESULTING IN VERY WEAK SURFACE PRESSURE
GRADIENT BECOMING NORTH TO NORTHEAST FLOW ABOVE 5K FT. THE 12Z MFL
SOUNDING CAPTURED THIS WELL AND ALSO SHOWS PWAT REMAINING AT AROUND
TWO INCHES. ALL OF THIS SPELLS CONVECTIVE DEVELOPMENT MOVING OFF TO
THE SOUTH AND THE HRRR HAS BEEN INDICATING THIS ALSO WITH GOOD
INITIAL TIMING AND LOCATION. THE SOUNDING ALSO SHOWED MID LEVEL
LAPSE RATES QUITE WEAK AT 5.8 DEGREES CELSIUS/KM AND A 500 MB
TEMPERATURE OF ONLY -5.9 WHICH IS NEARLY TWO DEGREES WARMER THAN
AVERAGE FOR EARLY AUGUST SO ONLY ISOLATED STRONG STORMS ARE EXPECTED
THIS AFTERNOON AT BEST.
THE MID LEVEL TROUGH WILL CONTINUE MOVING TO THE WEST IN THE SHORT
TERM WITH ALL GLOBAL MODELS IN VERY GOOD AGREEMENT SHIFTING IT INTO
THE CENTRAL BAHAMAS ON WEDNESDAY AND THE WESTERN BAHAMAS BY LATE
THURSDAY. AS THE TROUGH APPROACHES SOUTH FLORIDA, THE EASTERLY FLOW
WILL DEEPEN AS THE UPPER RIDGE TO THE NORTH MOVES LITTLE THROUGH
THIS PERIOD. THE ATMOSPHERIC MOISTURE PROFILE WILL CHANGE LITTLE
THROUGH WEDNESDAY AND WITH THE EAST FLOW DEEPENING, THE PRIMARY
THREAT FOR CONVECTIVE ACTIVITY WILL TEND TO BE MORNING SHOWERS ALONG
THE EAST COAST AND THEN SCATTERED SHOWERS/THUNDERSTORMS DEVELOPING
OVER THE INTERIOR DURING THE AFTERNOON AND MOVING TOWARDS THE
SOUTHWEST COAST. THE STEERING WINDS ARE ONLY EXPECTED TO BE AROUND 5
MPH SO THE THREAT WILL EXIST FOR POSSIBLE LOCALLY HEAVY RAINS IN THE
NAPLES AREA.
THERE COULD ACTUALLY BE LESS ACTIVITY ON THURSDAY AS THE TROUGH
APPROACHES WHICH PLACES SOUTH FLORIDA ON THE SUBSIDENCE SIDE. THIS
TROUGH CURRENTLY SHOWS UP VERY WELL IN WATER VAPOR IMAGERY WITH
STRONG SUBSIDENCE SHOWING UP TO ITS WEST. THE MODELS ALSO SHOW THE
LOW MAINTAINING ITS CURRENT STRENGTH SO ANOTHER REASON THERE COULD
BE LESS ACTIVITY. BY THURSDAY NIGHT, THE ATMOSPHERE WILL UNDERGO
GOOD DESTABILIZATION AS THE TROUGH MOVES INTO THE STRAITS OF
FLORIDA. THE GFS IS INDICATING 500 MB TEMPERATURES COOLING TO -11
SOUTHEAST OF KEY LARGO AND -10 OFF THE SOUTHEAST COAST. THE NAM IS A
TAD BID SLOWER WITH THE MOVEMENT BUT STILL SHOWS THIS SAME COLD POOL
ABOUT 50-100 MILES TO THE SOUTHEAST OF THE GFS POSITION. AT ANY
RATE, THIS COULD SET OFF SOME IMPRESSIVE LIGHTNING DISPLAYS TO OUR
SOUTHEAST THURSDAY EVENING AND NIGHT AS CONVECTIVE CELLS COULD
EASILY DEVELOP OVER THE ATLANTIC WATERS WITH SUCH COLD TEMPERATURES
ALOFT MOVING ACROSS THE GULF STREAM WATERS MAKING THE ENVIRONMENT
VERY UNSTABLE. BUT AS ALWAYS AS WE GET OUT WITH TIME, CONFIDENCE IS
LESS SO IT IS A WAIT AND SEE APPROACH.
.LONG TERM (FRIDAY-TUESDAY)...
LATE IN THE WEEK AND INTO THE WEEKEND AND EARLY NEXT WEEK, THE
TROUGH WILL CONTINUE WESTWARD INTO THE GULF OF MEXICO ALLOWING THE
ATLANTIC RIDGE TO ALSO BUILD WEST. THIS WILL STABILIZE THE
ATMOSPHERE ONCE AGAIN AND THE GFS IS ALSO SHOWING SIGNIFICANT DRYING
TAKING PLACE WITH PWAT DROPPING WELL UNDER TWO INCHES. SO WHILE
FRIDAY COULD REMAIN QUITE ACTIVE, MUCH LESS ACTIVITY IS LIKELY AS WE
GET INTO THE WEEKEND AND CROSS OVER INTO NEXT WEEK.
&&
.AVIATION...
ISOLATED HEAVY SHOWERS AND STORMS HAVE ALREADY DEVELOPED THIS
AFTERNOON ACROSS PORTIONS OF THE AREA...MOSTLY SOUTH OF A LINE FROM
FLL TO APF WITH THE MEAN LOW-LEVEL NORTHERLY FLOW IN PLACE. ALTHOUGH
MOST OF THE AFTERNOON/EVENING ACTIVITY SHOULD REMAIN JUST INLAND OF
THE TAF SITES...WE WILL CONTINUE TO INCLUDE VCTS AT MOST SITES FROM
21Z THROUGH THE EVENING HOURS AND UPDATE AS CONDITIONS EVOLVE.
OVERNIGHT TONIGHT THROUGH WEDNESDAY...THE FLOW SHOULD BECOME MORE
EASTERLY...WHICH WILL TRANSLATE TO THE BEST RAINFALL CHANCES SETTING
UP ACROSS THE INTERIOR AND WESTERN LOCATIONS OF SOUTH FLORIDA
THROUGH THE DAY WEDNESDAY.
&&
.MARINE...
LIGHT AND VARIABLE WIND TONIGHT WILL SLOWLY BECOME EAST BY
WEDNESDAY AND THEN STRENGTHENING LATER IN THE WEEK AS THE GRADIENT
TIGHTENS. THIS WILL BUILD SEAS OVER THE NEXT COUPLE OF DAYS BUT
REMAIN WELL BELOW ADVISORY CRITERIA.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 76 89 78 89 / 20 20 20 20
FORT LAUDERDALE 78 90 81 90 / 20 20 20 20
MIAMI 78 91 79 89 / 20 20 20 20
NAPLES 77 92 76 93 / 20 40 30 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MIAMI FL
134 AM EDT TUE AUG 6 2013
.AVIATION...
RIDGING CONTINUES TO CONTROL THE PATTERN THROUGH THIS TAF PERIOD.
A HIGH PRESSURE RIDGE OVER MOST OF THE GULF OF MEXICO HAS TURNED
TO MID LEVEL FLOW MORE NORTHERLY TONIGHT. THIS WILL KEEP UPPER
LEVEL CLOUD COVER OVER SOUTH FLORIDA FOR A GOOD PART OF THE OVER
NIGHT HOURS. TOMORROW, THE SEA BREEZE WILL DEVELOP AS CLOUDS
BECOME MORE SCT IN NATURE AND ALLOW DAYTIME HEATING. THIS WILL
ALLOW SHOWERS AND THUNDERSTORMS TO DEVELOP ONCE AGAIN, MAINLY IN
THE INTERIOR OF SOUTH FLORIDA. BY VERY EARLY AFTERNOON,
THUNDERSTORMS COULD BEGIN TO INFRINGE ON THE TAF SITES. HAVE TAKE
VCTS OUT FOR THE MORNING HOURS, AS CHANCES ARE LOWER THAN 30
PERCENT, BUT KEPT THEM IN AFTER 17Z AT ALL ATLANTIC SITES. KAPF
MAY SEE A SLIGHTLY EARLIER START. WINDS TOMORROW WILL TRY TO
PICKUP OUT OF THE NNW, BUT SHOULD BECOME INFLUENCED BY THE SEA
BREEZE AFTER 17Z. VFR CONDITIONS, OTHER THEN AREAS UNDER
CONVECTION, WILL BE THE GENERAL RULE THROUGH THE TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 815 PM EDT MON AUG 5 2013/
UPDATE...
CONVECTIVE ACTIVITY CONTINUES TO WANE ACROSS THE NORTHWEST
INTERIOR THIS EVENING...DEVOLVING INTO MAINLY MODERATE STRATIFORM
RAIN SHOWERS. LATEST HRRR CONTINUES TO SHOW THE REMAINDER OF THE
LINGERING RAINFALL TO DISSIPATE OVER THE NEXT FEW HOURS AS IT
SLOWLY HEADS TO THE SOUTH. INCREASED POPS THROUGH THE EVENING TO
ACCOUNT FOR THE RATHER LARGE STRATIFORM RAIN SHIELD. THE REMAINDER
OF THE FORECAST LOOKS GOOD AT THIS TIME.
PREV DISCUSSION... /ISSUED 208 PM EDT MON AUG 5 2013/
SHORT TERM (TONIGHT-TUESDAY NIGHT)...
CURRENT SYNOPTIC ANALYSIS SHOWS STRONG MID LEVEL RIDGE CENTERED OVER
TEXAS WITH ITS RIDGE AXIS STRETCHING TO THE SOUTHEAST ACROSS THE
STRAITS OF FLORIDA. AT THE SURFACE, A TROUGH EXTENDS ACROSS NORTH
CENTRAL FLORIDA INTO THE ATLANTIC WITH A SURFACE RIDGE OVER THE
FLORIDA KEYS. THIS IS CONTINUING THE WESTERLY STEERING FLOW FOR SOUTH
FLORIDA WITH THE BEST CHANCES FOR THUNDERSTORMS OVER THE INTERIOR
AND EAST COAST METRO REGION THROUGH EARLY THIS EVENING. THE
OVERNIGHT HOURS TONIGHT WILL BE MOSTLY TRANQUIL ONCE THE DIURNAL
HEATING CYCLE IS LOST AND THE LOW LEVEL FLOW BECOMES LIGHT AND
VARIABLE.
ON TUESDAY, SOUTH FLORIDA WILL UNDERGO A TRANSITIONAL PERIOD AS A
MID LEVEL INVERTED TROUGH APPROACHES FROM THE EAST. THIS TROUGH IS
CURRENTLY NEAR HISPANIOLA AND HAS BEEN WELL TRACKED BY THE GLOBAL
MODELS. IT WILL MOVE INTO THE EASTERN BAHAMAS ON TUESDAY WHICH WILL
GRADUALLY SHIFT THE MID/UPPER WIND FLOW TO A NORTHEAST DIRECTION. AT
THE SAME TIME, A SURFACE RIDGE WILL BUILD FROM THE CENTRAL GULF OF
MEXICO TO THE SOUTHEAST U.S. VEERING THE LOW LEVEL WIND TO AN EAST
DIRECTION ACROSS OUR REGION. THE FORECAST SOUNDINGS ARE INDICATING
PWAT REMAINING NEAR TWO INCHES SO STORMS WILL TEND TO DEVELOP NEAR
THE EAST COAST AND THEN SLOWLY DRIFT TOWARDS THE WEST INTO THE
EVERGLADES AND SOUTHWEST COAST. THE INVERTED TROUGH WILL MOVE INTO
THE CENTRAL BAHAMAS ON WEDNESDAY WITH A SURFACE RIDGE ACROSS NORTH
FLORIDA. THIS WILL RESULT IN A DEEP EASTERLY FLOW BECOMING
ESTABLISHED ACROSS SOUTH FLORIDA. THIS COULD BRING AN INCREASING
CHANCE OF NOCTURNAL SHOWERS ALONG THE EAST COAST TUESDAY NIGHT INTO
WEDNESDAY MORNING AND A THREAT FOR AFTERNOON THUNDERSTORMS ACROSS
THE INTERIOR AND SOUTHWEST COAST. AT THIS TIME, THE ATMOSPHERIC
INSTABILITY PROFILE DOES NOT CHANGE MUCH WITH PWAT CONTINUING AROUND
TWO INCHES AND WEAK MID LEVEL LAPSE RATES.
LONG TERM (WEDNESDAY-MONDAY)...
LOOKING AHEAD INTO THE EXTENDED PERIOD, THURSDAY APPEARS TO BE
SOMEWHAT UNCERTAIN AS TO THE CHANCE FOR THUNDER. THE INVERTED TROUGH
WILL MOVE ACROSS THE AREA WITH A STRONG DEEP LAYER RIDGE OVER NORTH
FLORIDA. THIS TRANSLATES TO EASTERLY FLOW THROUGH THE ENTIRE
ATMOSPHERE ACROSS SOUTH FLORIDA. IN FACT, THE LATEST 12Z RUN OF THE
GFS IS INDICATING A STEERING FLOW OF 15 TO 20 MPH BY THURSDAY
AFTERNOON AND IF THIS VERIFIES THE CHANCE FOR THUNDER WOULD BE
MINIMAL WITH A MAJORITY OF THE ACTION BEING FAST MOVING SHOWERS.
HOWEVER, THE TROUGH IN PLACE WILL ALSO DESTABILIZE THE MID LEVELS
WITH MODELS ALSO SHOWING SIGNIFICANT COOLING ALOFT. FOR THIS REASON,
DO NOT PLAN TO CHANGE FROM THE CURRENT FORECAST AND WILL WAIT FOR
FUTURE GUIDANCE BEFORE MAKING A DECISION. THE TROUGH WILL CONTINUE
MOVING WEST INTO THE GULF OF MEXICO ON FRIDAY AND INTO THE WEEKEND
WITH THE ATLANTIC RIDGE BUILDING WEST ACROSS THE PENINSULA. THE GFS
IS ALSO SHOWING SIGNIFICANT DRYING ALOFT WITH DEEP EASTERLY FLOW
CONTINUING SO THIS WILL SET THE STAGE FOR SCATTERED SHOWERS/ISOLATED
THUNDER MOSTLY OVER THE INTERIOR AND SOUTHWEST COAST.
MARINE...
THE SOUTHWEST TO WEST WIND WILL GRADUALLY SHIFT TO THE NORTHEAST
AND EAST ON TUESDAY THEN BECOMING EAST ON WEDNESDAY WHILE
INCREASING SPEED TO POSSIBLY 15 KNOTS OVER THE ATLANTIC. THIS WILL
RESULT IN BUILDING SEAS BY MIDWEEK BUT REMAINING BELOW ADVISORY
LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 77 90 78 / 50 20 30 20
FORT LAUDERDALE 89 80 89 79 / 50 20 30 30
MIAMI 91 78 89 80 / 50 20 30 30
NAPLES 92 76 92 76 / 40 20 40 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...13/SI
FORECAST DISCUSSION BELOW.
20
PREVIOUS LONG TERM DISCUSSION/THURSDAY NIGHT THROUGH TUESDAY/
UPPER RIDGE WILL CONTINUE ANCHORED ACROSS THE SOUTHERN PLAINS WITH A
SERIES OF UPPER SHORT WAVES MOVING ACROSS THE STATE. HAVE KEPT MAINLY
CHANCE POPS DURING THE DAY AND CHANCE OR SLIGHT CHANCE OVERNIGHT.
HOWEVER FOR SATURDAY LOOKS LIKE A FRONTAL BOUNDARY WILL DRIFT INTO
NORTH GEORGIA AND STALL FOR A DAY OR TWO. SO HAVE INCLUDED LIKELY
POPS FOR NORTH GEORGIA ON SATURDAY. UPPER FLOW TRANSITIONS TO A
TROUGH OVER THE EASTERN STATES BY THE FIRST OF THE WEEK. SOME DRYING
IS INDICATED FOR NORTH GEORGIA MONDAY AND TUESDAY...BUT NOT ENOUGH TO
REMOVE POPS ALTOGETHER. TEMPERATURES LOOK SEASONAL WITH MID TO UPPER
80S NORTH TO LOW AND MID 90S SOUTH.
41
&&
.HYDROLOGY...
FLOODING CONTINUES ACROSS PARTS OF NORTH GEORGIA. MORE RAIN IS
POSSIBLE ACROSS THESE ALREADY FLOODED AREAS THROUGH THIS EVENING.
WITH ANOTHER DISTURBANCE POSSIBLY AFFECTING THE STATE AGAIN
BY THURSDAY MORNING...ADDITIONAL RAINFALL IS EXPECTED AGAIN ON
THURSDAY. ALTHOUGH WIDESPREAD AMOUNTS OF A HALF INCH TO AN INCH ARE
EXPECTED THROUGH THURSDAY AFTERNOON...ISOLATED HIGHER AMOUNTS ARE
POSSIBLE. THE FLASH FLOOD WATCH CONTINUES TO BE IN EFFECT UNTIL 8AM
THURSDAY. HAVE OPTED NOT EXTEND IT TEMPORALLY AT THIS POINT DUE TO
UNCERTAINTY IN THE FORECAST...BUT IT IS A DISTINCT POSSIBILITY THAT
THE FLOOD WATCH WILL NEED TO BE EXTENDED UNTIL THURSDAY AFTERNOON
ACROSS PARTS OF NORTH GEORGIA.
11
&&
.AVIATION...
00Z UPDATE...
CONVECTION MAINLY ON THE DECREASE NEAR MOST TAF SITES THIS EVENING
AND LINGERING VCSH. IFR CIGS AND MVFR VSBYS ARE LIKELY AFTER ABOUT
09Z TONIGHT WITH POTENTIALLY SLIGHTLY LOWER HEIGHTS. WINDS SHOULD
STAY MOSTLY CALM TO SE. CONDITIONS GRADUALLY IMPROVING THURSDAY
NEAR MVFR/LOW END VFR CIGS AFTER 16Z. CHANCE FOR TSRA IN AFTERNOON
WILL WARRANT PROB30 FOR NOW AS BEST CHANCE LOOKS TO BE NORTH OF
SITES.
//ATL CONFIDENCE...00Z UPDATE...
MEDIUM ON OVERNIGHT CIGS/VSBYS.
HIGH ALL ELSE.
BAKER
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 70 88 72 90 / 40 50 30 30
ATLANTA 71 87 73 89 / 50 40 30 30
BLAIRSVILLE 69 81 68 86 / 60 70 40 40
CARTERSVILLE 71 87 72 90 / 60 60 30 40
COLUMBUS 74 92 74 93 / 70 40 30 30
GAINESVILLE 71 85 72 88 / 40 60 30 40
MACON 71 90 73 93 / 50 30 30 30
ROME 72 88 72 91 / 60 70 30 40
PEACHTREE CITY 70 87 72 90 / 60 40 30 30
VIDALIA 73 92 74 93 / 20 30 20 30
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 8 AM EDT THURSDAY FOR THE FOLLOWING
ZONES: BANKS...BARROW...BARTOW...BUTTS...CARROLL...CATOOSA...
CHATTOOGA...CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...DADE...
DAWSON...DEKALB...DOUGLAS...FANNIN...FAYETTE...FLOYD...FORSYTH...
GILMER...GORDON...GREENE...GWINNETT...HALL...HARALSON...HEARD...
HENRY...JACKSON...JASPER...LAMAR...LUMPKIN...MADISON...
MERIWETHER...MORGAN...MURRAY...NEWTON...NORTH FULTON...OCONEE...
OGLETHORPE...PAULDING...PICKENS...PIKE...POLK...PUTNAM...
ROCKDALE...SOUTH FULTON...SPALDING...TALIAFERRO...TOWNS...
TROUP...UNION...WALKER...WALTON...WHITE...WHITFIELD...WILKES.
&&
$$
SHORT TERM...11/BAKER
LONG TERM....20
AVIATION...BAKER
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
137 AM EDT TUE AUG 6 2013
.PREV DISCUSSION... /ISSUED 1041 PM EDT MON AUG 5 2013/
UPDATE...
NO MAJOR CHANGES TO THE FORECAST THIS EVENING. WILL NEED TO WATCH
TRENDS OVERNIGHT PER LATEST HRRR RUNS WHICH FIRE UP SOME STORMS
OVER CENTRAL GA AROUND 07Z. HARD TO FIND ANY EVIDENCE IN OTHER
SHORT TERM MODELS...BUT WORTH WATCHING NONETHELESS AS THE REMNANT
SEA BREEZE BOUNDARY WORKS INTO THAT REGION. OF MORE INTEREST IS
THE CONVECTION NOTED IN NE GA AFTER 07Z IN BOTH THE HRRR AND RUC.
WILL AGAIN NEED TO WATCH TRENDS AS ONLY THE LATEST RUNS HAVE BEEN
INDICATING THIS.
PREV DISCUSSION... /ISSUED 827 PM EDT MON AUG 5 2013/
PREV DISCUSSION... /ISSUED 348 PM EDT MON AUG 5 2013/
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
MODELS CONSISTENT THROUGH THE SHORT TERM WITH LARGE UPPER LEVEL
RIDGE OVER THE SOUTH-CENTRAL U.S. AND LONG-WAVE TROUGH PUSHING EAST
OF THE ATLANTIC COAST. MORE OF A ZONAL FLOW ANTICIPATED ACROSS THE
REGION AS A RESULT...BUT NOT BEFORE SHORTWAVE DROPS INTO THE AREA
TONIGHT AND INTO TUESDAY.
ALREADY SEEING SOME VERY ISOLATED SHOWER DEVELOPMENT THIS
AFTERNOON...MAINLY ALONG THE SOUTHEASTERN EDGE OF THE CWA WITH THE
INFLUENCE OF THE STALLED WEAK SURFACE BOUNDARY. EXPECT THE LOCATION
OF ACTIVITY TO TRANSITION TO THE NORTH AS SHORTWAVE APPROACHES. HAVE
CONTINUED WITH SLIGHT CHANCE TO CHANCE POPS EVERYWHERE THROUGH THE
AFTERNOON...WITH ONLY SLIGHT CHANCE POPS ACROSS THE NORTH AFTER
03-04Z. POPS INCREASE INTO TUESDAY MORNING AND CONTINUE WITH GOOD
CHANCE POPS THROUGH TUESDAY AS SHORTWAVE...COMBINED WITH GOOD
MOISTURE ACROSS THE AREA...RESULTS IN BETTER COVERAGE OF SHOWERS AND
THUNDERSTORMS.
AS FOR TEMPERATURES...HAVE GONE WITH A BLEND OF THE MODEL
GUIDANCE...WHICH HAS WORKED WELL THE LAST SEVERAL DAYS. TUESDAY
HIGHS WILL BE CLOSELY TIED TO PRECIP AND CLOUD COVER...SO ALTHOUGH
FORECAST IS SHOWING MID 80S TO NEAR 90...COULD SEE A FEW DEGREE
ADJUSTMENT BASED ON FUTURE MODEL RUN GUIDANCE.
31
LONG TERM /WEDNESDAY THROUGH MONDAY/...
NO MAJOR CHANGES WERE MADE TO THE EXTENDED PERIOD. LONG RANGE
MODELS CONTINUE TO SHOW A DEEP SOUTHERLY WIND FLOW BECOMING
ESTABLISHED ON WEDNESDAY AND AN OLD FRONTAL BOUNDARY BECOMING
DIFFUSE. THE INCREASING MOISTURE AND INSTABILITY WILL RESULT IN A
MORE SCATTERED TO NUMEROUS COVERAGE OF MAINLY DIURNALLY DRIVEN
CONVECTION THROUGH FRIDAY. MODELS SHOW A FRONTAL BOUNDARY APPROACHING
NORTH GA ON SATURDAY... PUSHING INTO NORTH GA ON SUNDAY... AND
BECOMING NEARLY STATIONARY ACROSS CENTRAL GA ON MONDAY. THIS WOULD
WARRANT SLIGHTLY HIGHER POPS ACROSS AT LEAST NORTH GA ON SATURDAY
AND SUNDAY... THEN ACROSS CENTRAL GA BY MONDAY... AS A DRIER... MORE
STABLE AIR MASS BEGINS TO SPREAD INTO NORTH GA ON MONDAY BEHIND
THE FRONT. ALTHOUGH WIDESPREAD ORGANIZED SEVERE STORMS ARE NOT
EXPECTED WITH THIS OVERALL SYNOPTIC WEATHER PATTERN... AN ISOLATED
PULSE STRONG TO SEVERE STORM CANNOT BE RULED OUT EACH DAY...
ESPECIALLY DURING MAX DAYTIME HEATING.
&&
.AVIATION...
06Z UPDATE...
MVFR CIGS ALREADY MOVING IN TOWARD AHN...AND THIS SHOULD SPREAD
WEST OVER THE NEXT COUPLE OF HOURS. MAY SEE BRIEF IFR...BUT
CONFIDENCE NOT HIGH. CSG MAY REMAIN VFR BUT CURRENT TAF DOES HAVE
THEM GOING MVFR TOWARD SUNRISE. WINDS STILL SORT OF ALL OVER THE
PLACE...LGT/VRB. EXPECT A MAINLY SE COMPONENT THOUGH SWITCHING TO
SW AROUND 15Z...BACK TO SOLIDLY SE AFTER 00Z. HAVE CONTINUED
PROB30 FOR AFTN TSRA BUT WILL REEVALUATE FOR 08Z AMD. INTRODUCED
MVFR CIGS AT 06Z TUESDAY AS WELL.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM-HIGH ON CIGS.
MEDIUM ON WINDS.
MEDIUM-HIGH ON CONVECTION.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 84 71 86 71 / 40 30 50 40
ATLANTA 86 72 86 72 / 40 30 50 30
BLAIRSVILLE 83 69 80 67 / 40 40 60 50
CARTERSVILLE 87 72 87 72 / 30 30 50 40
COLUMBUS 92 74 90 74 / 30 20 40 20
GAINESVILLE 83 71 83 71 / 40 30 50 40
MACON 88 71 88 72 / 40 20 40 20
ROME 89 72 88 72 / 30 30 50 40
PEACHTREE CITY 87 71 87 72 / 40 20 50 20
VIDALIA 88 72 91 73 / 40 20 40 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....ATWELL
AVIATION...TDP
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
236 PM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* IMPROVING CIG TRENDS EARLY THIS AFTERNOON.
* CHANCE OF TSRA TONIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
THE RESIDUAL LOW CLOUD REMNANTS FOLLOWING EARLIER PCPN ARE QUICKLY
DISSIPATING AND ALL SITES SHOULD GO VFR BTWN 18-19Z. THE REMAINDER
OF THE AFTERNOON AND INTO THE EVENING HOURS SHOULD BE QUIET WITH
VFR CIGS/VIS AND GENERALLY WESTERLY WINDS UNDER 10KT.
THE NEXT CONCERN WILL BE THE CHANCES FOR THUNDERSTORMS TO AFFECT
THE TERMINALS DURG THE EARLY MORNING HOURS. LATEST GUIDANCE STILL
SUGGESTS THE POSSIBILITY OF A THUNDERSTORM COMPLEX TO DEVELOP
TONIGHT FROM WISCONSIN TO IOWA IN ADVANCE OF AN APPROACHING COLD
FRONT. EXPECT THAT THE BEST WINDOW OF OPPORTUNITY FOR TSRA TO
IMPACT THE TERMINALS WILL BE GENERALLY BETWEEN 06Z-12Z. BASED ON
THE LATEST LOCAL HIGH RES MODELS...HAVE PUSHED BACK THE TIMING A
LITTLE FROM THE GOING FORECAST AND INTRODUCED A PROB30 GROUP
OUTLINING THE MOST LIKELY TIMING BASED ON THE LATEST
GUIDANCE...WHICH WOULD BRING TSRA TO THE RFD AREA BTWN 06-10Z AND
THE CHICAGO AREA BTWN 08-12Z. THE TS POTENTIAL SHOULD QUICKLY SHUT
OFF FOLLOWING THE FROPA...SO THE DURATION OF TS WILL BE HIGHLY
DEPENDENT ON THE FRONTAL PROGRESSION SPEED. SO...WILL GO WITH THE
PROB30 GROUP FOR NOW AND REFINE THE FORECAST TIMING...POSSIBLY
UPGRADING TO A TEMPO OR PREVAILING GROUP AS ANTICIPATED CONDITIONS
WARRANT.
THE ONLY OTHER SIGNIFICANT CONCERN WILL BE WIND DIRECTION TRENDS.
CURRENTLY...ANTICIPATE THAT WINDS SHOULD REMAIN GENERALLY WLY
THROUGH THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING. AS
THE FRONT APPROACHES...EXPECT THAT WINDS SHOULD BACK TO MORE SLY
BEFORE QUICKLY VEERING NWLY FOLLOWING THE FROPA. WITH THE
EXPECTATION OF THE ENVIRONMENT AROUND ANY THUNDERSTORMS...WINDS
SHOULD GENERALLY REMAIN AT OR BELOW 10KT GIVING A RELATIVELY
PRESSURE GRADIENT OVER THE REGION AND THE LACK OF A STRONG COLD
AIR PUSH FOLLOWING THE FROPA.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TONIGHT...WITH
LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1251 PM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* IMPROVING CIG TRENDS EARLY THIS AFTERNOON.
* CHANCE OF TSRA TONIGHT.
KREIN
//DISCUSSION...UPDATED 18Z...
THE RESIDUAL LOW CLOUD REMNANTS FOLLOWING EARLIER PCPN ARE QUICKLY
DISSIPATING AND ALL SITES SHOULD GO VFR BTWN 18-19Z. THE REMAINDER
OF THE AFTERNOON AND INTO THE EVENING HOURS SHOULD BE QUIET WITH
VFR CIGS/VIS AND GENERALLY WESTERLY WINDS UNDER 10KT.
THE NEXT CONCERN WILL BE THE CHANCES FOR THUNDERSTORMS TO AFFECT
THE TERMINALS DURG THE EARLY MORNING HOURS. LATEST GUIDANCE STILL
SUGGESTS THE POSSIBILITY OF A THUNDERSTORM COMPLEX TO DEVELOP
TONIGHT FROM WISCONSIN TO IOWA IN ADVANCE OF AN APPROACHING COLD
FRONT. EXPECT THAT THE BEST WINDOW OF OPPORTUNITY FOR TSRA TO
IMPACT THE TERMINALS WILL BE GENERALLY BETWEEN 06Z-12Z. BASED ON
THE LATEST LOCAL HIGH RES MODELS...HAVE PUSHED BACK THE TIMING A
LITTLE FROM THE GOING FORECAST AND INTRODUCED A PROB30 GROUP
OUTLINING THE MOST LIKELY TIMING BASED ON THE LATEST
GUIDANCE...WHICH WOULD BRING TSRA TO THE RFD AREA BTWN 06-10Z AND
THE CHICAGO AREA BTWN 08-12Z. THE TS POTENTIAL SHOULD QUICKLY SHUT
OFF FOLLOWING THE FROPA...SO THE DURATION OF TS WILL BE HIGHLY
DEPENDENT ON THE FRONTAL PROGRESSION SPEED. SO...WILL GO WITH THE
PROB30 GROUP FOR NOW AND REFINE THE FORECAST TIMING...POSSIBLY
UPGRADING TO A TEMPO OR PREVAILING GROUP AS ANTICIPATED CONDITIONS
WARRANT.
THE ONLY OTHER SIGNIFICANT CONCERN WILL BE WIND DIRECTION TRENDS.
CURRENTLY...ANTICIPATE THAT WINDS SHOULD REMAIN GENERALLY WLY
THROUGH THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING. AS
THE FRONT APPROACHES...EXPECT THAT WINDS SHOULD BACK TO MORE SLY
BEFORE QUICKLY VEERING NWLY FOLLOWING THE FROPA. WITH THE
EXPECTATION OF THE ENVIRONMENT AROUND ANY THUNDERSTORMS...WINDS
SHOULD GENERALLY REMAIN AT OR BELOW 10KT GIVING A RELATIVELY
PRESSURE GRADIENT OVER THE REGION AND THE LACK OF A STRONG COLD
AIR PUSH FOLLOWING THE FROPA.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TONIGHT...WITH
LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
* HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1103 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* CIG TRENDS WITH LOW MVFR CIGS LEVEL THIS MORNING.
* TIMING THE IMPROVEMENT OF CIGS DURING THE LATE MORNING HOURS.
IMPROVEMENT MIGHT BE A LITTLE LATER THAN TAF INDICATES...BUT
WHEN IMPROVEMENT COMES...SHOULD BE QUICK.
* CHANCE OF TSRA TONIGHT.
KREIN
//DISCUSSION...UPDATED 12Z...
THERE ARE A FEW LINGERING SHOWERS LEFT OVER FROM THE OVERNIGHT
STORMS ACROSS NORTH CENTRAL ILLINOIS. HOWEVER...THE PRIMARY FORECAST
CONCERNS IN THE NEAR TERM WILL BE CIGS AND VIS TRENDS THIS
MORNING. ATTENTION THEN TURNS TO LATER TONIGHT INTO WEDNESDAY
MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A MESSY
MORNING ACROSS THE AREA. CIGS AND VIS ARE TANKING IN THE WAKE OF
THE HIGHER CLOUD COVER AND AREA OF SHOWERS. MOST AREAS WEST OF THE
CHICAGO AREA ARE UNDER 800 FEET WITH VIS NOW DOWN TO 1/2 SM AT
KRFD. I EXPECT THESE DETERIORATING CONDITIONS TO CONTINUE TO
OVERSPREAD THE EASTERN TAF SITES EARLY THIS MORNING. I SUSPECT
THAT THE VIS WILL DROP AT KORD AND KMDW AS WELL FOR A PERIOD EARLY
THIS MORNING...BUT CONFIDENCE ON HOW LOW THEY WILL DROP IS
LOW...BUT MVFR VIS AROUND 5 SM IS CERTAINLY POSSIBLE GIVEN THE
TRENDS TO THE WEST. SO BY FAR THE BIGGEST DEAL WILL BE THE LOW CIGS.
CIGS WILL PROB BE A BIT SLOW TO RECOVER THIS MORNING...WITH NO BIG
IMPROVEMENTS UNTIL AFTER 14-15 UTC THIS MORNING. HOWEVER...ONCE
THINGS IMPROVE LATER THIS MORNING...AVIATION WEATHER CONCERNS
SHOULD BE AT A MINIMUM THROUGH THE REST OF THE DAY.
IT APPEARS LIKELY THAT A COMPLEX OF THUNDERSTORMS WILL DEVELOP
WEST OF THE AREA ACROSS IOWA AND SOUTHWESTERN WISCONSIN DURING THE
EVENING TODAY. THIS ACTIVITY APPEARS THAT IT WILL MOVE OVER
NORTHERN ILLINOIS LATER TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY
AT THE EASTERN TAF SITS. IT MAY BE IN A WEAKENING STATE AS IT
ARRIVES ACROSS NORTHEASTERN ILLINOIS...BUT I DID CONTINUE THE
MENTION OF SHRA AND VCTS ALL THE TAFS AFTER 06 UTC TONIGHT. IT IS
POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW HOURS PRIOR
TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE TONIGHT
INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE APPROACHES
THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN THE AIR MASS
AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* LOW CONFIDENCE IN TIMING OF IMPROVEMENT OF THE MVFR CIGS THIS
MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TONIGHT...WITH
LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
913 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* CIG AND VIS TRENDS WITH LOW MVFR/IFR CIGS DOWN IN THE 800-1000
FEET LEVEL THIS MORNING.
* TIMING THE IMPROVEMENT OF CIGS DURING THE MID TO LATE MORNING
HOURS. IMPROVEMENT MIGHT BE A LITTLE LATER THAN TAF
INDICATES...BUT WHEN IMPROVEMENT COMES...SHOULD BE QUICK.
* CHANCE OF TSRA TONIGHT.
KREIN
//DISCUSSION...UPDATED 12Z...
THERE ARE A FEW LINGERING SHOWERS LEFT OVER FROM THE OVERNIGHT
STORMS ACROSS NORTH CENTRAL ILLINOIS. HOWEVER...THE PRIMARY FORECAST
CONCERNS IN THE NEAR TERM WILL BE CIGS AND VIS TRENDS THIS
MORNING. ATTENTION THEN TURNS TO LATER TONIGHT INTO WEDNESDAY
MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A MESSY
MORNING ACROSS THE AREA. CIGS AND VIS ARE TANKING IN THE WAKE OF
THE HIGHER CLOUD COVER AND AREA OF SHOWERS. MOST AREAS WEST OF THE
CHICAGO AREA ARE UNDER 800 FEET WITH VIS NOW DOWN TO 1/2 SM AT
KRFD. I EXPECT THESE DETERIORATING CONDITIONS TO CONTINUE TO
OVERSPREAD THE EASTERN TAF SITES EARLY THIS MORNING. I SUSPECT
THAT THE VIS WILL DROP AT KORD AND KMDW AS WELL FOR A PERIOD EARLY
THIS MORNING...BUT CONFIDENCE ON HOW LOW THEY WILL DROP IS
LOW...BUT MVFR VIS AROUND 5 SM IS CERTAINLY POSSIBLE GIVEN THE
TRENDS TO THE WEST. SO BY FAR THE BIGGEST DEAL WILL BE THE LOW CIGS.
CIGS WILL PROB BE A BIT SLOW TO RECOVER THIS MORNING...WITH NO BIG
IMPROVEMENTS UNTIL AFTER 14-15 UTC THIS MORNING. HOWEVER...ONCE
THINGS IMPROVE LATER THIS MORNING...AVIATION WEATHER CONCERNS
SHOULD BE AT A MINIMUM THROUGH THE REST OF THE DAY.
IT APPEARS LIKELY THAT A COMPLEX OF THUNDERSTORMS WILL DEVELOP
WEST OF THE AREA ACROSS IOWA AND SOUTHWESTERN WISCONSIN DURING THE
EVENING TODAY. THIS ACTIVITY APPEARS THAT IT WILL MOVE OVER
NORTHERN ILLINOIS LATER TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY
AT THE EASTERN TAF SITS. IT MAY BE IN A WEAKENING STATE AS IT
ARRIVES ACROSS NORTHEASTERN ILLINOIS...BUT I DID CONTINUE THE
MENTION OF SHRA AND VCTS ALL THE TAFS AFTER 06 UTC TONIGHT. IT IS
POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW HOURS PRIOR
TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE TONIGHT
INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE APPROACHES
THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN THE AIR MASS
AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* LOW CONFIDENCE IN TIMING OF IMPROVEMENT OF THE LOW MVFR/IFR
CIGS THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
648 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* CIG AND VIS TRENDS WITH LOW MVFR/IFR CIGS DOWN IN THE 700-1000
FEET LEVEL EARLY THIS MORNING.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MID TO
LATE MORNING HOURS. BIG IMPROVEMENTS NOT LIKELY UNTIL AFTER
14-15 UTC.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 12Z...
THERE ARE A FEW LINGERING SHOWERS LEFT OVER FROM THE OVERNIGHT
STORMS ACROSS NORTH CENTRAL ILLINOIS. HOWEVER...THE PRIMARY FORECAST
CONCERNS IN THE NEAR TERM WILL BE CIGS AND VIS TRENDS THIS
MORNING. ATTENTION THEN TURNS TO LATER TONIGHT INTO WEDNESDAY
MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A MESSY
MORNING ACROSS THE AREA. CIGS AND VIS ARE TANKING IN THE WAKE OF
THE HIGHER CLOUD COVER AND AREA OF SHOWERS. MOST AREAS WEST OF THE
CHICAGO AREA ARE UNDER 800 FEET WITH VIS NOW DOWN TO 1/2 SM AT
KRFD. I EXPECT THESE DETERIORATING CONDITIONS TO CONTINUE TO
OVERSPREAD THE EASTERN TAF SITES EARLY THIS MORNING. I SUSPECT
THAT THE VIS WILL DROP AT KORD AND KMDW AS WELL FOR A PERIOD EARLY
THIS MORNING...BUT CONFIDENCE ON HOW LOW THEY WILL DROP IS
LOW...BUT MVFR VIS AROUND 5 SM IS CERTAINLY POSSIBLE GIVEN THE
TRENDS TO THE WEST. SO BY FAR THE BIGGEST DEAL WILL BE THE LOW CIGS.
CIGS WILL PROB BE A BIT SLOW TO RECOVER THIS MORNING...WITH NO BIG
IMPROVEMENTS UNTIL AFTER 14-15 UTC THIS MORNING. HOWEVER...ONCE
THINGS IMPROVE LATER THIS MORNING...AVIATION WEATHER CONCERNS
SHOULD BE AT A MINIMUM THROUGH THE REST OF THE DAY.
IT APPEARS LIKELY THAT A COMPLEX OF THUNDERSTORMS WILL DEVELOP
WEST OF THE AREA ACROSS IOWA AND SOUTHWESTERN WISCONSIN DURING THE
EVENING TODAY. THIS ACTIVITY APPEARS THAT IT WILL MOVE OVER
NORTHERN ILLINOIS LATER TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY
AT THE EASTERN TAF SITS. IT MAY BE IN A WEAKENING STATE AS IT
ARRIVES ACROSS NORTHEASTERN ILLINOIS...BUT I DID CONTINUE THE
MENTION OF SHRA AND VCTS ALL THE TAFS AFTER 06 UTC TONIGHT. IT IS
POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW HOURS PRIOR
TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE TONIGHT
INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE APPROACHES
THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN THE AIR MASS
AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM CONFIDENCE IN TIMING OF IMPROVEMENT OF THE LOW MVFR/IFR
CIG/VIS THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY
SOUTH OF CHICAGO THURSDAY NIGHT.
MONDAY...SLIGHT CHANCE OF TSRA.
KJB
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
421 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCED
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE SCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
WHILE THE CONVECTION IS LIKELY TO BE ON A WEAKENING TREND INTO
WEDNESDAY MORNING...IF NOT ALREADY OVERNIGHT...GUIDANCE HAS AGREED
ON A SLOWER MOVEMENT OF THE FRONT IN THE PAST 24 HOURS. SO HAVE
INCREASED POPS IN EASTERN AREAS DURING EARLY WEDNESDAY.
CONFIDENCE...MEDIUM.
WEDNESDAY AFTERNOON THROUGH FRIDAY...AS THE FRONT EASES IN SPEED
THERE IS CONCERN FOR CONVECTION IN THE SOUTHEAST PART OF THE
FORECAST AREA WEDNESDAY AFTERNOON. HIGH MOISTURE WILL STILL OWE TO
MODEST TO HIGH INSTABILITY ALONG THE BOUNDARY. EVEN A SLOWER
FRONTAL MOVEMENT MAY MEAN WE COULD HAVE A SEVERE WEATHER THREAT IN
THE FAR SOUTHERN FORECAST AREA. FOR THE TIME BEING MAINTAIN THE
CHANCE POPS IN THE SOUTHERN AREA.
LARGER INCREASES IN POPS WERE MADE FOR THU NIGHT AND INTO FRI
ACROSS THE SOUTHEAST HALF OF THE FORECAST AS ONE AND POSSIBLY
MULTIPLE WAVES TRAVERSE THE BOUNDARY...SPREADING SOUTHERLY 850MB
FLOW NORTH OF THE FEATURE POTENTIALLY LEADING TO SOME SHOWERS AND
STORMS ACROSS OUR AREA...DESPITE NORTHERLY SURFACE FLOW. THE MAIN
FOCUS FOR ANYTHING OF HIGH IMPACT STILL LOOKS TO BE WELL SOUTH OF
THE AREA. FOR TEMPERATURES ON WED-FRI HAVE GONE JUST A COUPLE
DEGREES ABOVE AN OFFICIAL/MODEL BLEND.
THIS WEEKEND...LITTLE CHANGES MADE TO THE GOING FORECAST AS HIGH
PRESSURE IS STILL FAVORED IN THAT TIME YIELDING LIKELY PLEASANT
WEATHER. GUIDANCE MAY BE A LITTLE QUICK ON BRINGING PRECIP
CHANCES BACK SUNDAY NIGHT...BUT FOR THE TIME BEING HAVE GONE WITH
A BLEND DUE TO ATTENTION ON THE SHORT TERM.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* ISOLATED SHOWERS/ VCTS EARLY THIS MORNING.
* CIG TRENDS WITH LOW MVFR CIGS DOWN AROUND 1500 FEET EARLY THIS
MORNING.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MID TO
LATE MORNING HOURS.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED
TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN A BRIEF PERIOD OF SHOWERS THIS MORNING...WITH
VCTS.
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING FOR A
PERIOD THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
420 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURFACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTION ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCD
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVECTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPAGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE DCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
CONFIDENCE...MEDIUM.
THE REST OF THE DISCUSSION WILL BE SENT SHORTLY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* ISOLATED SHOWERS/ VCTS EARLY THIS MORNING.
* CIG TRENDS WITH LOW MVFR CIGS DOWN AROUND 1500 FEET EARLY THIS MORNING.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MID TO
LATE MORNING HOURS.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN A BRIEF PERIOD OF SHOWERS THIS MORNING...WITH
VCTS.
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING FOR A
PERIOD THIS MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
343 AM CDT TUE AUG 6 2013
.DISCUSSION...
340 AM CDT
THERE ARE MULTIPLE FORECAST CHALLENGES THIS MORNING...WITH
SEVERAL OF THOSE TIED TO THUNDER CHANCES ASSOCIATED WITH A COOL
FRONTAL ARRIVAL TONIGHT INTO WEDNESDAY MORNING AND THEN ITS SLOW
DEPARTURE FROM THE REGION THURSDAY INTO FRIDAY...WITH CHANCES THEN
MAINLY ACROSS THE SOUTH. OF COURSE IN AND AROUND FRONTAL SYSTEMS
TEMPERATURES ALWAYS OFFER AN EXCITING CHALLENGE AS WELL.
SYNOPSIS...THE PREVALENT UPPER RIDGE ACROSS THE SOUTHERN U.S. WILL
CONTINUE ITS GRADUAL DAMPENING TREND IN RESPONSE TO AN UPPER
TROUGH ADVANCING SOUTH ACROSS CENTRAL AND SOUTH CENTRAL CANADA. A
PERSISTENT 90KT+ NORTHWESTERLY JET BETWEEN THESE UPPER FEATURES
STRETCHES OVER THE FORECAST AREA WITH SMALL SCALE IMPULSES NOTED
IN THIS FLOW AND RESPONSIBLE FOR SOME OF THE EARLY MORNING STORMS
AS OF 330 AM. THE SURFACE MAP ACROSS THE MIDWEST THIS MORNING IS
CHARACTERIZED BY ONLY A 2MB PRESSURE GRADIENT FROM HERE THROUGH
THE CENTRAL PLAINS...WITH AN ELONGATED AND BAGGY SURACE TROUGH
FROM MN THROUGH OK. THIS TROUGH WILL SHARPEN UP INTO A COOL FRONT
BY LATE THIS AFTERNOON AS CYCLOGENESIS OCCURS ACROSS THE UPPER
MIDWEST UNDER FORCING OF THE UPPER TROUGH. THE PARENT SURFACE LOW
LOOKS TO REACH ITS DEEPEST PRESSURE /~1003MB/ THIS EVE AS IT NEARS
LAKE SUPERIOR AND THEN MOVE NORTHEAST. INITIALLY THIS WILL BRING A
COOL FRONT INTO THE AREA. AS THE FRONT STRETCHES OUT WITH THE LOW
MOVING AWAY THE FORWARD MOMENTUM IS EXPECTED TO SLOW LATER
WEDNESDAY WITH THE BOUNDARY STALLING NEAR OR NOT FAR NORTH OF THE
OHIO VALLEY THU AND FRI. A SECONDARY COOL FRONT WILL USHER THIS
BOUNDARY FURTHER SOUTH COME LATER FRI.
THIS MORNING...SCATTERED CONVECTION HAS HELD ITS OWN NEAR ROCKFORD
ASSOCIATED WITH A MID-LEVEL SPEED MAX AND SHEARED SHORT
WAVE...ALONG WITH SUBTLE 850-925MB CONVERGENCE ON 20-25KT SW/WSW
LLJ FLOW. ITS TOUGH TO SAY HOW LONG THIS ACTIVITY WILL LAST AS THE
FORCING IS WEAK AND ITS ALREADY PERSISTED LONGER THAN INITIALLY
THOUGHT. GIVEN THAT ITS TIED IN PART TO THE LLJ THIS SHOULD EASE
IN COVERAGE AS IT NEARS OR MOVES INTO THE CHICAGO METRO AREA FROM
6-9 AM. SOME OF THIS HAS BEEN FAIRLY EFFICIENT AT RAIN PRODUCTION
WITH SOME ESTIMATES ON RADAR OF OVER AN INCH IN WINNEBAGO COUNTY.
AMDAR DATA INDICATES THE CLOUDS APART FROM THE CONVECTINO ARE OF
AROUND 2000-4000 FT THICK...WITH FLIGHTS OUT OF CHICAGO NEAR THE
DEEPER END. THIS WILL LIKELY TAKE SEVERAL HOURS TO PEEL AWAY INTO
A CU LAYER...SO A SLOW TEMPERATURE CLIMB SHOULD INITIALLY BE SEEN.
CONFIDENCE...LOW/MEDIUM.
THIS AFTERNOON...SHORT WAVE RIDGING IS EXPECTED TO MOVE OVER THE
AREA DURING THIS TIME OFFERING LIMITED FORCING FOR RAIN DESPITE
BUILDING INSTABILITY IN THE SOUTHERLY FLOW SLOWLY MOVING IN.
THERE SHOULD BE SOME SUNSHINE AND ABOVE NORMAL 850MB AND 925MB
TEMPERATURES WOULD SUPPORT MEDIAN READINGS NEAR THE UPPER 80S IN
OUR AREA BASED ON LOCAL RESEARCH. HAVE MID TO UPPER 80S FORECAST
FOR MUCH OF THE AREA...WITH LOWER 80S IMMEDIATELY ALONG THE IL
LAKE SHORE. THIS IS SUPPORTED BY THE RAP MODEL RUN...WHICH IS ONE
OF THE WARMEST GUIDANCE YET HAS A VERY SLOW TEMPERATURE CLIMB
THROUGH 9-10 AM...COINCIDENT WITH OUR FORECAST CLOUD COVER WHICH
ADDS CREDIBIILITY TO ITS SOLUTION.
CONFIDENCE...MEDIUM.
TONIGHT INTO WEDNESDAY MORNING...THIS IS THE PERIOD THAT HAS THE
BEST POTENTIAL FOR STORMS...ESPECIALLY LATE TONIGHT. THE SUITE OF
MODEL GUIDANCE HAS BEEN IN SOLID AGREEMENT THE PAST 24 HOURS OF
CONVECTION DEVELOPING UPSTREAM ACROSS IA AND SOUTHERN MN THIS EVE
AS HEIGHT FALLS OVERSPREAD THE DEVELOPING COOL FRONT. A PRONOUNCD
SHORT WAVE ACROSS MT EARLY THIS MORNING SEEMS TO CORRELATE WELL
WITH MOVING OVER THAT REGION DURING EARLY EVE. AS CONVECTION
LIKELY DEVELOPS IT IS ANTICIPATED TO MOVE EAST SOUTHEAST WITHIN
THE FAST PACED WESTERLY FLOW...WITH SEVERAL CONVECTIVE ALLOWING
MODELS PAINTING ORGANIZED/MCS CONVECTION. THIS SHOULD BE ABLE TO
FEED ON MODESTLY UNSTABLE AND VERY MOIST AIR FEEDING NORTHWARD.
PWATS HAVE BEEN 2 INCHES OR HIGHER FOR MULTIPLE DAYS UP TO
SOUTHERN MO AND SOUTHEAST KS AND SOME OF THAT AIR MASS /PWATS
~1.75 IN./ WILL BE BROUGHT UP INTO OUR REGION ON 30KT OF 700-925MB
MOISTURE TRANSPORT.
ITS POSSIBLE FOR SCATTERED ELEVATED CONVECTION WITHIN THIS
INCREASING MOIST FLOW AHEAD OF THE MAIN CONVERGENCE...BUT THE MAIN
FOCUS STILL LOOKS TO BE OVERNIGHT. THE MAIN UNCERTAINTY IS IF THE
CONVECTION CAN HOLD ITS OWN THROUGH THE OVERNIGHT OR WILL IT SHOW
A WEAKENING TREND...ESPECIALLY IF MORE CONVECTION DEVELOPS
SOUTH OF THE AREA IN MO AND SOUTHWEST IL ROBBING OUR MOIST RETURN.
HAVE STILL GONE AHEAD AND BOOSTED QPF VALUES ACROSS THE WESTERN
HALF OF THE AREA FROM WHAT WPC HAD AS LOCALIZED HIGHER AMOUNTS ARE
FAVORED IN THE REGION...ESPECIALLY IF CONVCTION IS ORGANIZED.
THE FLASH FLOOD THREAT WILL PROBABLY BE LIMITED WITH PROPOGATION
OF THE HEAVIEST RAIN LIKELY TO BE QUICK ENOUGH AND ANTECEDENT
CONDITIONS NOT TOO BAD OFF WITH RECENT DRYNESS. THIS WESTERN PART
OF THE CWA IS ALSO THE PORTION WHERE IF ANY STORMS ARE ABLE TO
REACH A SEVERE THRESHHOLD THE THREAT WOULD BE A LITTLE MORE
FAVORED...NAMELY A WIND THREAT WITH APPRECIABLE DCAPE VALUES
FORECAST BY THE NAM AND GFS /800-1200 J/KG/ AND POSSIBLE COLD POOL
PROPAGATION. THE THREAT FOR SEVERE WEATHER THOUGH STILL APPEARS
LOW.
CONFIDENCE...MEDIUM.
THE REST OF THE DISCUSSION WILL BE SENT SHORTLY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* ISOLATED SHOWERS EARLY THIS MORNING.
* CIG TRENDS WITH MVFR CIGS DOWN AROUND 1500 FEET BY DAYBREAK.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MORNING.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING
OVERNIGHT AND LINGERING THROUGH MID MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
259 AM CDT TUE AUG 6 2013
.DISCUSSION...
755 PM CDT
EVENING UPDATE:
MADE TWEAKS TO EVENING GRIDS TO BACK OFF TO ISOLATED SHRA MENTION
FOR APPROXIMATELY NORTHEASTERN HALF OF CWA. SHEARED OUT WAVE AND
MID LEVEL SPEED MAX CONTINUES TO PUSH ACROSS REGION WITH
SIGNIFICANT DRYING NOTED ON WATER VAPOR IN WAKE OF THIS WAVE.
LATEST RAP MESOANALYSIS HAS SHOWN IN INCREASE IN ELEVATED CAPE BUT
00Z DVN RAOB INDICATES THAT THIS IS LIKELY OVERDONE WITH VERY
MARGINAL INSTABILITY AND WEAK MID LEVEL LAPSE RATES ON THE
SOUNDING. WITH THE FORCING FROM THE MIDLEVEL WAVE
OVERHEAD...RETURNS OVER SOUTHWEST WISCONSIN HAVE INCREASED A BIT
IN RECENT SCANS BUT GIVEN THAT INSTABILITY FURTHER DIMINISHES INTO
OUR CWA...THIS ACTIVITY WILL LIKELY ONLY SURVIVE INTO CWA AS
SPOTTY PRIMARILY LIGHT SHOWERS. AN OUTSIDE CHANCE EXISTS FOR AN
ISOLATED T-STORM. THEN WENT WITH A DRY FORECAST AFTER MIDNIGHT FOR
ENTIRE AREA AS FORCING FROM VORT MAX WILL TRANSLATE EAST OF US BY
ABOUT MIDNIGHT.
ATTENTION WILL THEN TURN TO FOG POTENTIAL OVERNIGHT AS AIR MASS
REMAINS MOIST AND WINDS WILL CONTINUE TO DIMINISH. UNCERTAINTY AS
TO WHETHER STRATUS OR FOG IS THE PRIMARY MODE BUT IF BETTER CLEARING
CAN OCCUR...FOG WOULD BECOME MORE FAVORABLE AND EVEN POTENTIALLY
BECOME LOCALLY DENSE. OBS OVER SW WISCONSIN SHOW VSBY BETWEEN 2
AND 4 MILES AND LATEST GUIDANCE STILL SUPPORTS BEST CHANCE FOR
MORE WIDESPREAD FOG TO DEVELOP WELL WEST OF THE LAKEFRONT SO WILL
CONTINUE TO MONITOR OBSERVATIONAL TRENDS THIS EVENING AND MAKE
FURTHER UPDATES IF NEEDED. UPDATED ZONE PRODUCT HAS BEEN SENT.
RC
//PREV DISCUSSION...
312 PM CDT
A PREDOMINANTLY NORTHWESTERLY UPPER FLOW PATTERN WILL BE IN PLACE
THROUGH THE PERIOD WITH OCCASIONAL BUCKLING TO A MORE WESTERLY
DIRECTION OVER THE NEXT FEW DAYS. AS A RESULT...TIMING MODEST PRECIP
CHANCES WILL BE THE MAIN CHALLENGE THROUGH LATE WEEK. WATER VAPOR
IMAGERY SHOWS AN UPPER LOW CENTERED OVER SOUTHWESTERN PORTIONS OF
HUDSON BAY WHILE A LARGE UPPER ANTICYCLONE SPINS OVER TEXAS. BETWEEN
THE TWO...IS A BELT OF NORTHWESTERLY UPPER FLOW STRETCHED FROM THE
NORTHERN U.S. ROCKIES TO THE SOUTHEAST COAST. A CLOSER LOOK AT
SATELLITE SHOWS SEVERAL EMBEDDED SHORTWAVES WITHIN THIS FLOW...WITH
ONE HAVING PASSED OVER THE AREA EARLIER TODAY WITH ANOTHER
APPROACHING LATE THIS AFTERNOON. A LARGER SCALE TROUGH AXIS EXTENDS
FROM THE HUDSON BAY LOW WEST-SOUTHWEST WHERE A SMALLER SCALE
CIRCULATION IS NOTED OVER SOUTHERN ALBERTA. THIS WILL BE KEY IN OUR
WEATHER TUESDAY NIGHT AND WEDNESDAY. FURTHER WEST...ANOTHER UPPER
LOW IS CUTOFF OFF THE NORTHERN CALIFORNIA COAST AND MOVING VERY
LITTLE AS A RESULT. AT THE SURFACE...HIGH PRESSURE IS CENTERED OVER
EASTERN OHIO AND WESTERN PENNSYLVANIA WHILE A LOW IS CENTERED OVER
NORTHERN ONTARIO. A TROUGH AXIS EXTENDS SOUTHWARD FROM THE LOW INTO
EASTERN MINNESOTA AND IOWA.
THIS EVENING THROUGH TUESDAY...A WEAK SHORTWAVE CONTINUES TO CROSS
THE LOCAL AREA WITH A SMALL CLUSTER OF SHRA/TSRA WORKING
EAST-SOUTHEAST ACROSS THE FAR NORTHWEST ILLINOIS BORDER. THIS LOOKS
TO MAINTAIN ITSELF OVER THE NEXT FEW HOURS BUT LITTLE IF ANY LOW
LEVEL INSTABILITY HAS DEVELOPED THANKS TO AN EXTENSIVE...BUT
THINNING...CLOUD SHIELD. WHAT HAS DEVELOPED THOUGH SUGGESTS THAT
THIS CLUSTER WILL WORK SOUTHEAST TOWARD ROCKFORD...ROCHELLE...AND ON
INTO THE WESTERN/SOUTHWESTERN CHICAGO METRO IF IT MAINTAINS. IN
ADDITION...SOME SPOTTY ACTIVITY MAY DEVELOP AROUND THIS CLUSTER
INTO THE EVENING. A FEW STRONGER CORES HAVE POPPED UP FROM TIME TO
TIME IN THE LAST FEW RADAR SCANS WITH THE ACTIVITY BUT WITH SUCH
LIMITED INSTABILITY...THOUGH THERE IS STRONG SHEAR...MORE THAN AN
ISOLATED HAIL CORE OR WIND GUST LOOKS UNLIKELY. CHANCES WILL
DIMINISH THROUGH THE EVENING. THE AFOREMENTIONED TROUGH AXIS/COOL
FRONT MOVING ACROSS MINNESOTA WILL CONTINUE EASTWARD BUT FALL APART
WITH TIME OVERNIGHT. MID LEVEL DRYING IS EXPECTED OVERNIGHT AND WITH
NO COHERENT SOURCE OF FORCING DO NOT SEE MUCH CHANCE FOR PRECIP BY
LATE TONIGHT...IF NOT BEFORE THAT. THE AREA WILL BE BETWEEN SYSTEMS
TUESDAY WHICH SHOULD LEAD TO DRY CONDITIONS THROUGH AT LEAST THE
FIRST PART OF THE DAY BEFORE SMALL CHANCES INCREASE LATER IN THE DAY
AS THE NEXT TROUGH APPROACHES. MORNING CLOUD COVER WILL BE THE WILD
CARD FOR TEMPS AS IT MAY BE EXTENSIVE ALONG WITH SOME MORNING
FOG...BUT A DECREASE IS EXPECTED THROUGH LATE MORNING...WITH SOME
DIURNAL CU AND SOME APPROACHING CIRRUS FOR THE AFTERNOON. H85 TEMPS
WILL BE QUITE WARM RELATIVE TO RECENT DAYS...WITH READINGS AROUND
+16C. THIS COMBINED WITH EXPECTED INCREASE IN SUNSHINE DURING THE
AFTERNOON...AND A MODEST SOUTH-SOUTHWEST WIND SHOULD ALLOW FOR HIGHS
TO WARM INTO THE LOW TO MID 80S...WITH A FEW UPPER 80S POSSIBLE IF
CLOUD COVER IS LESS THAN FORECAST.
TUESDAY NIGHT AND WEDNESDAY...THE UPPER LOW OVER HUDSON BAY WILL
RE-POSITION ITSELF ACROSS EASTERN MANITOBA TUESDAY WITH ANOTHER
TROUGH AXIS ROTATING AROUND IT. THIS WILL PUSH ANOTHER WEAK COOL
FRONT SOUTHEASTWARD ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
RIVER VALLEY INTO TUESDAY EVENING WHICH WILL THEN CROSS THE LOCAL
AREA EARLY WEDNESDAY. THIS FRONT LOOKS TO BE BETTER ORGANIZED THAN
THE ONE APPROACHING TONIGHT GIVEN THAT THE PARENT SFC LOW WILL BE
FURTHER SOUTH AND BETTER ORGANIZED AS IT CROSSES THE UPPER LAKES AND
CENTRAL ONTARIO. A MOIST AIRMASS WILL BE IN PLACE ACROSS THE AREA
WITH PRECIPITABLE WATER VALUES RUNNING BETWEEN 1.4 AND 1.7 INCHES.
IT APPEARS THAT THERE MAY BE SEVERAL SHORTWAVES THAT CROSS THE AREA
FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING WITH THE MAIN FRONT
NOT PASSING UNTIL WEDNESDAY MORNING. WILL MAINTAIN THE LOW END
LIKELY POPS FROM THE PREVIOUS FORECAST BUT REFINE THE TIMING...WITH
THE BETTER CHANCES STARTING TUESDAY NIGHT. A DRYING TREND IS
EXPECTED WEDNESDAY AFTERNOON AS HIGH PRESSURE DROPS SOUTHEASTWARD
INTO THE AREA SHIFTING WINDS TO THE NORTH AND EAST. HIGHS MAY STILL
BE RATHER MILD WEDNESDAY WITH LOW TO MID 80S...THANKS TO THE UPPER
FLOW BEING ZONAL KEEPING MID LEVEL COOL ADVECTION AT A MINIMUM
THROUGH THE AFTERNOON. HOWEVER...TEMPS NEAR THE LAKESHORE WILL
LIKELY COOL AS WINDS TURN ONSHORE.
THURSDAY THROUGH THE WEEKEND...THE FRONT WILL STALL OUT SOUTH OF THE
AREA INTO EARLY THURSDAY WHILE HIGH PRESSURE MOVES OVERHEAD AND THEN
SHIFTS TO THE EAST. MID LEVEL COOL ADVECTION WILL BE UNDERWAY INTO
THURSDAY LEADING TO HIGHS BACK INTO THE MID TO UPPER 70S...WITH A
FEW 80S SOUTH. COOLEST READINGS WILL BE ALONG THE LAKESHORE AS
ONSHORE FLOW CONTINUES. ONE LAST TROUGH AXIS IS EXPECTED TO ROTATE
AROUND THE UPPER LOW OVER MANITOBA/ONTARIO. GUIDANCE IS LESS CLEAR
IN HOW THIS EVOLVES...WITH SOME SUGGESTION OF A STRONGER WAVE
THANKS TO PHASING OF ENERGY BETWEEN THE MAIN UPPER LOW AND ENERGY
OVERTOPPING A RIDGE ACROSS THE PACIFIC NORTHWEST. THIS WILL HAVE A
BIG IMPACT ON LOCAL POPS LATER THURSDAY AND FRIDAY AS A STRONGER
SYSTEM WOULD FORCE BETTER ORGANIZED SURFACE LOW/INVERTED TROUGH
DEVELOPMENT ACROSS THE MID MISSISSIPPI RIVER VALLEY ALONG THE OLD
FRONTAL BOUNDARY. THE STRONGER THE SURFACE LOW THE FURTHER NORTH THE
OLD BOUNDARY WILL MOVE AND THE GREATER THE CHANCES FOR PRECIP ACROSS
THE CWA. CONFIDENCE IS LOW GIVEN THAT THE UPPER FLOW PATTERN IS
ACTIVE BETWEEN NOW AND THEN AND ITS EVOLUTION MAY BE AFFECTED. AT
THE MOMENT IT APPEARS THAT THE BEST PRECIP CHANCES WILL BE SOUTH OF
THE AREA LATER THURSDAY/FRIDAY...WITH ANOTHER SURFACE HIGH BUILDING
IN INTO SATURDAY. HAVE BETTER CONFIDENCE IN THE MAIN UPPER LOW
MOVING EASTWARD WHICH WILL ALLOW RIDGING TO BUILD WEST AND A MORE
PRONOUNCED NORTHWEST FLOW ALOFT OF THE LOCAL AREA FOR THE WEEKEND.
THIS WILL LIKELY RESULT IN HIGHS THAT CONTINUE TO BE SEVERAL DEGREES
BELOW NORMAL. EXPECT DRY CONDITIONS SATURDAY BEFORE A SLIGHT INFLUX
IN MOISTURE ARRIVES SUNDAY/MONDAY WITH THE UPPER FLOW LOOKING TO
BECOME MORE ACTIVE. WILL LEAVE SUNDAY DRY FOR NOW.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* ISOLATED SHOWERS EARLY THIS MORNING.
* CIG TRENDS WITH MVFR CIGS DOWN AROUND 1500 FEET BY DAYBREAK.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MORNING.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING
OVERNIGHT AND LINGERING THROUGH MID MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
258 AM CDT
SOUTHERLY FLOW IN THE 10 TO 20 KT RANGE WILL CONTINUE TODAY AND
TONIGHT AS A TROUGH OF SURFACE LOW PRESSURE CONTINUES TO ORGANIZE
ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. IT APPEARS THAT
THUNDERSTORMS WILL BECOME LIKELY TONIGHT AHEAD OF THE COLD
FRONT...WHICH SHOULD MOVE ACROSS THE LAKE ON WEDNESDAY MORNING. ONCE
THIS FRONT PASSES...THE WINDS WILL BECOME NORTHERLY BY LATE
WEDNESDAY...AND COULD PICK UP TO 15 TO 20 KT FOR A PERIOD AS SURFACE
HIGH PRESSURE BUILDS IN FROM THE WEST. THE SURFACE HIGH SHOULD SET
UP OVER LAKE MICHIGAN FOR THURSDAY...AND THIS SHOULD RESULT IN
ABATING WINDS INTO THURSDAY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
133 AM CDT TUE AUG 6 2013
.DISCUSSION...
755 PM CDT
EVENING UPDATE:
MADE TWEAKS TO EVENING GRIDS TO BACK OFF TO ISOLATED SHRA MENTION
FOR APPROXIMATELY NORTHEASTERN HALF OF CWA. SHEARED OUT WAVE AND
MID LEVEL SPEED MAX CONTINUES TO PUSH ACROSS REGION WITH
SIGNIFICANT DRYING NOTED ON WATER VAPOR IN WAKE OF THIS WAVE.
LATEST RAP MESOANALYSIS HAS SHOWN IN INCREASE IN ELEVATED CAPE BUT
00Z DVN RAOB INDICATES THAT THIS IS LIKELY OVERDONE WITH VERY
MARGINAL INSTABILITY AND WEAK MID LEVEL LAPSE RATES ON THE
SOUNDING. WITH THE FORCING FROM THE MIDLEVEL WAVE
OVERHEAD...RETURNS OVER SOUTHWEST WISCONSIN HAVE INCREASED A BIT
IN RECENT SCANS BUT GIVEN THAT INSTABILITY FURTHER DIMINISHES INTO
OUR CWA...THIS ACTIVITY WILL LIKELY ONLY SURVIVE INTO CWA AS
SPOTTY PRIMARILY LIGHT SHOWERS. AN OUTSIDE CHANCE EXISTS FOR AN
ISOLATED T-STORM. THEN WENT WITH A DRY FORECAST AFTER MIDNIGHT FOR
ENTIRE AREA AS FORCING FROM VORT MAX WILL TRANSLATE EAST OF US BY
ABOUT MIDNIGHT.
ATTENTION WILL THEN TURN TO FOG POTENTIAL OVERNIGHT AS AIR MASS
REMAINS MOIST AND WINDS WILL CONTINUE TO DIMINISH. UNCERTAINTY AS
TO WHETHER STRATUS OR FOG IS THE PRIMARY MODE BUT IF BETTER CLEARING
CAN OCCUR...FOG WOULD BECOME MORE FAVORABLE AND EVEN POTENTIALLY
BECOME LOCALLY DENSE. OBS OVER SW WISCONSIN SHOW VSBY BETWEEN 2
AND 4 MILES AND LATEST GUIDANCE STILL SUPPORTS BEST CHANCE FOR
MORE WIDESPREAD FOG TO DEVELOP WELL WEST OF THE LAKEFRONT SO WILL
CONTINUE TO MONITOR OBSERVATIONAL TRENDS THIS EVENING AND MAKE
FURTHER UPDATES IF NEEDED. UPDATED ZONE PRODUCT HAS BEEN SENT.
RC
//PREV DISCUSSION...
312 PM CDT
A PREDOMINANTLY NORTHWESTERLY UPPER FLOW PATTERN WILL BE IN PLACE
THROUGH THE PERIOD WITH OCCASIONAL BUCKLING TO A MORE WESTERLY
DIRECTION OVER THE NEXT FEW DAYS. AS A RESULT...TIMING MODEST PRECIP
CHANCES WILL BE THE MAIN CHALLENGE THROUGH LATE WEEK. WATER VAPOR
IMAGERY SHOWS AN UPPER LOW CENTERED OVER SOUTHWESTERN PORTIONS OF
HUDSON BAY WHILE A LARGE UPPER ANTICYCLONE SPINS OVER TEXAS. BETWEEN
THE TWO...IS A BELT OF NORTHWESTERLY UPPER FLOW STRETCHED FROM THE
NORTHERN U.S. ROCKIES TO THE SOUTHEAST COAST. A CLOSER LOOK AT
SATELLITE SHOWS SEVERAL EMBEDDED SHORTWAVES WITHIN THIS FLOW...WITH
ONE HAVING PASSED OVER THE AREA EARLIER TODAY WITH ANOTHER
APPROACHING LATE THIS AFTERNOON. A LARGER SCALE TROUGH AXIS EXTENDS
FROM THE HUDSON BAY LOW WEST-SOUTHWEST WHERE A SMALLER SCALE
CIRCULATION IS NOTED OVER SOUTHERN ALBERTA. THIS WILL BE KEY IN OUR
WEATHER TUESDAY NIGHT AND WEDNESDAY. FURTHER WEST...ANOTHER UPPER
LOW IS CUTOFF OFF THE NORTHERN CALIFORNIA COAST AND MOVING VERY
LITTLE AS A RESULT. AT THE SURFACE...HIGH PRESSURE IS CENTERED OVER
EASTERN OHIO AND WESTERN PENNSYLVANIA WHILE A LOW IS CENTERED OVER
NORTHERN ONTARIO. A TROUGH AXIS EXTENDS SOUTHWARD FROM THE LOW INTO
EASTERN MINNESOTA AND IOWA.
THIS EVENING THROUGH TUESDAY...A WEAK SHORTWAVE CONTINUES TO CROSS
THE LOCAL AREA WITH A SMALL CLUSTER OF SHRA/TSRA WORKING
EAST-SOUTHEAST ACROSS THE FAR NORTHWEST ILLINOIS BORDER. THIS LOOKS
TO MAINTAIN ITSELF OVER THE NEXT FEW HOURS BUT LITTLE IF ANY LOW
LEVEL INSTABILITY HAS DEVELOPED THANKS TO AN EXTENSIVE...BUT
THINNING...CLOUD SHIELD. WHAT HAS DEVELOPED THOUGH SUGGESTS THAT
THIS CLUSTER WILL WORK SOUTHEAST TOWARD ROCKFORD...ROCHELLE...AND ON
INTO THE WESTERN/SOUTHWESTERN CHICAGO METRO IF IT MAINTAINS. IN
ADDITION...SOME SPOTTY ACTIVITY MAY DEVELOP AROUND THIS CLUSTER
INTO THE EVENING. A FEW STRONGER CORES HAVE POPPED UP FROM TIME TO
TIME IN THE LAST FEW RADAR SCANS WITH THE ACTIVITY BUT WITH SUCH
LIMITED INSTABILITY...THOUGH THERE IS STRONG SHEAR...MORE THAN AN
ISOLATED HAIL CORE OR WIND GUST LOOKS UNLIKELY. CHANCES WILL
DIMINISH THROUGH THE EVENING. THE AFOREMENTIONED TROUGH AXIS/COOL
FRONT MOVING ACROSS MINNESOTA WILL CONTINUE EASTWARD BUT FALL APART
WITH TIME OVERNIGHT. MID LEVEL DRYING IS EXPECTED OVERNIGHT AND WITH
NO COHERENT SOURCE OF FORCING DO NOT SEE MUCH CHANCE FOR PRECIP BY
LATE TONIGHT...IF NOT BEFORE THAT. THE AREA WILL BE BETWEEN SYSTEMS
TUESDAY WHICH SHOULD LEAD TO DRY CONDITIONS THROUGH AT LEAST THE
FIRST PART OF THE DAY BEFORE SMALL CHANCES INCREASE LATER IN THE DAY
AS THE NEXT TROUGH APPROACHES. MORNING CLOUD COVER WILL BE THE WILD
CARD FOR TEMPS AS IT MAY BE EXTENSIVE ALONG WITH SOME MORNING
FOG...BUT A DECREASE IS EXPECTED THROUGH LATE MORNING...WITH SOME
DIURNAL CU AND SOME APPROACHING CIRRUS FOR THE AFTERNOON. H85 TEMPS
WILL BE QUITE WARM RELATIVE TO RECENT DAYS...WITH READINGS AROUND
+16C. THIS COMBINED WITH EXPECTED INCREASE IN SUNSHINE DURING THE
AFTERNOON...AND A MODEST SOUTH-SOUTHWEST WIND SHOULD ALLOW FOR HIGHS
TO WARM INTO THE LOW TO MID 80S...WITH A FEW UPPER 80S POSSIBLE IF
CLOUD COVER IS LESS THAN FORECAST.
TUESDAY NIGHT AND WEDNESDAY...THE UPPER LOW OVER HUDSON BAY WILL
RE-POSITION ITSELF ACROSS EASTERN MANITOBA TUESDAY WITH ANOTHER
TROUGH AXIS ROTATING AROUND IT. THIS WILL PUSH ANOTHER WEAK COOL
FRONT SOUTHEASTWARD ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
RIVER VALLEY INTO TUESDAY EVENING WHICH WILL THEN CROSS THE LOCAL
AREA EARLY WEDNESDAY. THIS FRONT LOOKS TO BE BETTER ORGANIZED THAN
THE ONE APPROACHING TONIGHT GIVEN THAT THE PARENT SFC LOW WILL BE
FURTHER SOUTH AND BETTER ORGANIZED AS IT CROSSES THE UPPER LAKES AND
CENTRAL ONTARIO. A MOIST AIRMASS WILL BE IN PLACE ACROSS THE AREA
WITH PRECIPITABLE WATER VALUES RUNNING BETWEEN 1.4 AND 1.7 INCHES.
IT APPEARS THAT THERE MAY BE SEVERAL SHORTWAVES THAT CROSS THE AREA
FROM TUESDAY EVENING THROUGH WEDNESDAY MORNING WITH THE MAIN FRONT
NOT PASSING UNTIL WEDNESDAY MORNING. WILL MAINTAIN THE LOW END
LIKELY POPS FROM THE PREVIOUS FORECAST BUT REFINE THE TIMING...WITH
THE BETTER CHANCES STARTING TUESDAY NIGHT. A DRYING TREND IS
EXPECTED WEDNESDAY AFTERNOON AS HIGH PRESSURE DROPS SOUTHEASTWARD
INTO THE AREA SHIFTING WINDS TO THE NORTH AND EAST. HIGHS MAY STILL
BE RATHER MILD WEDNESDAY WITH LOW TO MID 80S...THANKS TO THE UPPER
FLOW BEING ZONAL KEEPING MID LEVEL COOL ADVECTION AT A MINIMUM
THROUGH THE AFTERNOON. HOWEVER...TEMPS NEAR THE LAKESHORE WILL
LIKELY COOL AS WINDS TURN ONSHORE.
THURSDAY THROUGH THE WEEKEND...THE FRONT WILL STALL OUT SOUTH OF THE
AREA INTO EARLY THURSDAY WHILE HIGH PRESSURE MOVES OVERHEAD AND THEN
SHIFTS TO THE EAST. MID LEVEL COOL ADVECTION WILL BE UNDERWAY INTO
THURSDAY LEADING TO HIGHS BACK INTO THE MID TO UPPER 70S...WITH A
FEW 80S SOUTH. COOLEST READINGS WILL BE ALONG THE LAKESHORE AS
ONSHORE FLOW CONTINUES. ONE LAST TROUGH AXIS IS EXPECTED TO ROTATE
AROUND THE UPPER LOW OVER MANITOBA/ONTARIO. GUIDANCE IS LESS CLEAR
IN HOW THIS EVOLVES...WITH SOME SUGGESTION OF A STRONGER WAVE
THANKS TO PHASING OF ENERGY BETWEEN THE MAIN UPPER LOW AND ENERGY
OVERTOPPING A RIDGE ACROSS THE PACIFIC NORTHWEST. THIS WILL HAVE A
BIG IMPACT ON LOCAL POPS LATER THURSDAY AND FRIDAY AS A STRONGER
SYSTEM WOULD FORCE BETTER ORGANIZED SURFACE LOW/INVERTED TROUGH
DEVELOPMENT ACROSS THE MID MISSISSIPPI RIVER VALLEY ALONG THE OLD
FRONTAL BOUNDARY. THE STRONGER THE SURFACE LOW THE FURTHER NORTH THE
OLD BOUNDARY WILL MOVE AND THE GREATER THE CHANCES FOR PRECIP ACROSS
THE CWA. CONFIDENCE IS LOW GIVEN THAT THE UPPER FLOW PATTERN IS
ACTIVE BETWEEN NOW AND THEN AND ITS EVOLUTION MAY BE AFFECTED. AT
THE MOMENT IT APPEARS THAT THE BEST PRECIP CHANCES WILL BE SOUTH OF
THE AREA LATER THURSDAY/FRIDAY...WITH ANOTHER SURFACE HIGH BUILDING
IN INTO SATURDAY. HAVE BETTER CONFIDENCE IN THE MAIN UPPER LOW
MOVING EASTWARD WHICH WILL ALLOW RIDGING TO BUILD WEST AND A MORE
PRONOUNCED NORTHWEST FLOW ALOFT OF THE LOCAL AREA FOR THE WEEKEND.
THIS WILL LIKELY RESULT IN HIGHS THAT CONTINUE TO BE SEVERAL DEGREES
BELOW NORMAL. EXPECT DRY CONDITIONS SATURDAY BEFORE A SLIGHT INFLUX
IN MOISTURE ARRIVES SUNDAY/MONDAY WITH THE UPPER FLOW LOOKING TO
BECOME MORE ACTIVE. WILL LEAVE SUNDAY DRY FOR NOW.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* ISOLATED SHOWERS EARLY THIS MORNING.
* CIG TRENDS WITH MVFR CIGS DOWN AROUND 1500 FEET BY DAYBREAK.
* TIMING THE IMPROVEMENT OF THESE LOWER CIGS DURING THE MORNING.
* GOOD CHANCE OF TSRA TUESDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM WILL BE CIGS AND
VIS...ESPECIALLY THROUGH MID MORNING. ATTENTION THEN TURNS TO LATER
TONIGHT INTO WEDNESDAY MORNING WITH OUR NEXT CHANCE FOR TSRA.
ABUNDANT LOW LEVEL MOISTURE ACROSS THE AREA IS CREATING A RATHER
COMPLICATED CIG AND VIS FORECAST OVERNIGHT...AS AREAS WHERE THE
CLOUDS ARE DISSIPATING LOWER CLOUDS AND FOG ARE DEVELOPING. CURRENT
THINKING IS THAT IT MAY TAKE A FEW MORE HOURS TO GET CIGS TO DROP
BELOW 2000 FT AGL AT THE EASTERN TAF SITES...AND WITH MORE CLOUD
COVER THE THREAT FOR FOG APPEARS LOW...ESPECIALLY AT ORD AND MDW.
THE FOG THREAT IS A BIT UNCERTAIN AT DPA AND RFD AS LOW CIGS MAY BE
THE RULE. HOWEVER...WITH VERY LOW DEW POINT DEPRESSIONS...IT WILL
NOT TAKE MUCH TO GET THE VIS TO TANK. WITH THIS IN MIND...I DECIDED TO
LEAVE THE TEMPO GROUPS FOR A PERIOD OF LOW VIS IN THE NEW TAF
FORECAST AT RFD AND DPA.
THERE HAVE AS BEEN A CONTINUED REDEVELOPMENT OF MAINLY SHOWERS
ACROSS FAR NORTHERN ILLINOIS AS THE FLOW ALOFT REMAINS RATHER
UNSETTLED. THIS WILL LIKELY CONTINUE TO BE THE CASE FOR THE NEXT FEW
HOURS ACROSS THE AREA. I EXTENDED THE VCSH TO ACCOUNT FOR THESE
SHOWERS. OVERALL THE THREAT FOR THUNDER WILL BE
LOW...HOWEVER...THERE HAVE BEEN A FEW STRIKES IN THE CELL ACROSS
STEPHENSON COUNTY. THIS CELL COULD APPROACH KRFD AFTER 07 UTC.
CIGS LOOK TO BE SLOW TO INCREASE THIS MORNING...BUT ONCE THEY
DO...THINGS SHOULD BE QUIET UNTIL TONIGHT. IT APPEARS LIKELY THAT A
COMPLEX OF THUNDERSTORMS WILL DEVELOP WEST OF THE AREA ACROSS IOWA
AND SOUTHWESTERN WISCONSIN DURING THE EVENING TODAY. THIS ACTIVITY
APPEARS THAT IT WILL MOVE OVER NORTHERN ILLINOIS LATER
TONIGHT...LIKELY AFTER 06 UTC...ESPECIALLY AT THE EASTERN TAF SITS.
I DID ADD A MENTION OF SHRA AND VCTS TO THE ORD 30 HR TAF AFTER 08
UTC. IT IS POSSIBLE THAT ACTIVITY COULD IMPACT THE TERMINAL A FEW
HOURS PRIOR TO 08 UTC...HOWEVER...THE BEST TIMING APPEARS TO BE LATE
TONIGHT INTO EARLY WEDNESDAY MORNING AS A SURFACE FRONTAL ZONE
APPROACHES THE AREA. DUE TO THE HIGH MOISTURE CONTENT EXPECTED IN
THE AIRMASS AHEAD OF THIS FRONT...A PERIOD OF HEAVY RAINFALL IS
PROBABLE...WHICH COULD REDUCE THE VIS DOWN UNDER 2 MILES FOR BRIEF
PERIODS. THERE IS ALSO A SMALL RISK OF SOME STRONG WINDS WITH SOME
OF THE STORMS...ESPECIALLY OUT BY RFD.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE IN MVFR CIG/VIS CONDITIONS DEVELOPING
OVERNIGHT AND LINGERING THROUGH MID MORNING.
* MEDIUM TO HIGH CONFIDENCE IN THUNDERSTORMS LATER TUESDAY
NIGHT...WITH ONLY LOW TO MEDIUM CONFIDENCE ON THE EXACT TIMING.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...CHANCE TSRA MAINLY MORNING. OTHERWISE VFR.
THURSDAY THROUGH SUNDAY...VFR. SLIGHT CHANCE TSRA MAINLY SOUTH OF
CHICAGO THURSDAY NIGHT.
RATZER
&&
.MARINE...
240 PM...A BROAD WEAK TROUGH EXTENDING ACROSS THE PLAINS FROM A
SLIGHTLY STRONGER LOW OVER ONTARIO WILL SLOWLY MOVE EAST ACROSS
THE WESTERN LAKES WEDNESDAY...WITH THE LOW OVER ONTARIO SLOWLY
MOVING EAST THROUGH MID WEEK. AHEAD OF THIS TROUGH...SOUTHERLY
WINDS HAVE INCREASED TO 10-20 KT AND FORECAST SOUNDINGS SUGGEST
THE POTENTIAL FOR SOME WINDS INTO THE 15-25 KT RANGE THIS EVENING
BEFORE SLOWLY DIMINISHING OVERNIGHT. ONCE THE TROUGH/COLD FRONT
MOVES ACROSS THE LAKE MIDDAY WEDNESDAY...WINDS WILL SHIFT
NORTHERLY WITH A PERIOD OF 10-20 KTS POSSIBLE BUT APPEARS THAT
WOULD BE SHORT LIVED AS HIGH PRESSURE SPREADS ACROSS THE LAKES
REGION WEDNESDAY NIGHT INTO THURSDAY. THE LOW OVER ONTARIO FINALLY
SHIFTS EAST INTO QUEBEC ON FRIDAY...WITH A WEAK COLD FRONT MOVING
ACROSS THE WESTERN LAKES FRIDAY NIGHT SHIFTING WINDS BACK
NORTHERLY INTO SATURDAY WITH ANOTHER HIGH MOVING ACROSS THE LAKES
SATURDAY NIGHT INTO SUNDAY. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
224 PM EDT TUE AUG 6 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 243 AM EDT TUE AUG 6 2013
WARMER AIR IS SET TO ARRIVE IN INDIANA TODAY AS HIGH PRESSURE OVER
THE EAST COAST PROVIDES A WARMER AND MORE HUMID SOUTHERLY FLOW
ALONG WITH DRY WEATHER. A MORE ACTIVE WEATHER PATTERN WILL TAKE
SHAPE THROUGH THE MIDDLE OF THE WEEK AS A COLD FRONT IS EXPECTED
TO PUSH TOWARD INDIANA LATE TONIGHT AND STALL ACROSS SOUTHERN
INDIANA THROUGH THURSDAY THE FRONT WILL BRING CHANCES FOR SHOWERS
AND STORMS FROM LATE TONIGHT THROUGH FRIDAY.
HIGH PRESSURE IS EXPECTED TO ARRIVE LATE FRIDAY AND BRING A RETURN
TO DRY WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 944 AM EDT TUE AUG 6 2013
BUMPED UP CLOUD COVER THIS MORNING DUE TO SATELLITE TRENDS AS LOW
DECK HAS BEEN OVERSPREADING THE AREA. LOOKS LIKE IT WILL TAKE A
BIT LONGER TO SCATTER OUT AND THUS TRENDED MOSTLY CLOUDY TO LAST
THROUGH MID AFTERNOON FOR MOST OF THE AREA. WITH THIS INCREASE IN
CLOUD COVER HAVE ALSO LOWER HIGH TEMPERATURES FOR THE DAY...ONLY
BY A DEGREE OR SO IN THE NORTH AND CENTRAL BUT BY A FEW DEGREES IN
THE SOUTHWEST SINCE DEBRIS CLOUDS WILL LIKELY KEEP THAT AREA
MOSTLY CLOUDY THROUGH MUCH OF THE DAY. RAP SHOWS SOME ISOLATED TO
SCATTERED CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON BUT OTHER
MODELS STILL LOOK DRY. WITH SOME SUBSIDENCE AND DRY AIR ALOFT AND
THE RAP ALSO SHOWING SOME THINGS NOW THAT ARE NOT OCCURRING WILL
CONTINUE WITH DRY FORECAST THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 243 AM EDT TUE AUG 6 2013
MAIN FOCUS DURING THIS PERIOD WILL BE POPS.
MODELS ARE IN PRETTY GOOD AGREEMENT OF THE OVERALL TREND OF A
WET...ACTIVE PATTERN.
GFS AND NAM BOTH SUGGEST THE FIRST SHORT WAVE ARRIVING IN THE AREA
LATE TONIGHT AMID THE NW FLOW ALOFT. FORECAST SOUNDINGS HINT AT A
SLOW TOP DOWN STYLE SATURATION BY 12Z. THUS WILL KEEP THE EVENING
DRY...BUT TREND TOWARD HIGHER CHANCES FOR RAIN DURING THE
OVERNIGHT HOURS. 310K GFS ISENTROPIC SURFACE ALSO SHOWS A GOOD
SURGE OF ISENTROPIC LIFT WITH SPECIFIC HUMIDITIES RISING TO NEAR
8 G/KG. WILL TREND LOWS AT OR ABOVE MAVMOS VALUES DUE TO EXPECTED
WARM AIR ADVECTION...CLOUDS...AND PRECIP.
ON WEDNESDAY MORNING...THE GFS AND NAM SUGGEST A COLD FRONT
TROUGH LINGERING ACROSS THE STATE AS THE UPPER SUPPORT FROM THE
OVERNIGHT PERIOD DEPARTS. FORECAST SOUNDINGS SUGGEST DRYING
OUT...HOWEVER PLENTY OF CAPE...IN EXCESS OF 2000 J/KG REMAINS
AVAILABLE. PWATS ARE ALSO NEAR 1.75 INCHES...VERY MOIST. CONVECTIVE
TEMPS ON WEDNESDAY AFTERNOON ARE VERY ATTAINABLE...IN THE LOWER
80S...AND THE GFS 310K ISENTROPIC SURFACE SHOWS STRONG LIFT WITH
AGAIN A VERY MOIST AIR MASS WITH SPECIFIC HUMIDITIES OVER 9 G/KG.
MEANWHILE AT THE SURFACE A WARM FRONT STALLS ACROSS SOUTHERN
INDIANA...FURTHER ACTING AS A FOCUS FOR LOWER LEVEL CONVERGENCE.
THUS ANY HEATING ON WEDNESDAY SHOULD LEAD TO DEVELOPMENT. WILL
TREND POPS AT OR ABOVE MAVMOS...PARTICULARLY DURING THE AFTERNOON.
GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND HIGHS AT OR BELOW
MAVMOS.
GFS DEPICTS A SHORT WAVE RIDING ACROSS THE WARM FRONT ACROSS THE
SOUTHERN PARTS OF THE FORECAST AREA ON WEDNESDAY NIGHT...AGAIN A
VERY WARM AND MOIST AIR MASS WILL REMAIN IN PLACE. FORECAST
SOUNDINGS ACROSS THE AREA ALSO INDICATE DEEP SATURATION BY
THURSDAY...AND NOW WITH PWATS IN EXCESS OF 2 INCHES. FAVORABLE
CAPE IS ALSO AVAILABLE. ALOFT IT APPEARS AS IF THE TROPICAL PLUME
THAT IS CURRENTLY FLOWING ACROSS THE PLAINS INTO THE DEEP SOUTH WILL
SHIFT EAST BY WEDNESDAY AND THURSDAY...ALLOWING THIS DEEPER
MOISTURE TO SURGE INTO INDIANA AND THE OHIO VALLEY...PARTICULARLY
ACROSS THE SOUTHERN PARTS OF OUR STATE. THUS WILL CONTINUE TO
RAISE POPS THROUGH THURSDAY NIGHT...TRENDING HIGHS COOLER THAN
MAVMOS AND LOWS WARMER...GIVEN THE EXPECTED CLOUDS AND RAIN.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 224 PM EDT TUE AUG 6 2013
EXTENDED MODELS IN FAIR AGREEMENT ON A COLD FRONT DROPPING TO NEAR
THE OHIO RIVER 12Z SATURDAY WITH NORTHWEST FLOW LOFT. THE FRONT
SHOULD SETTLE GRADUALLY FURTHER SOUTH THROUGH THE WEEKEND WITH HIGH
PRESSURE BUILDING IN BEHIND THE FRONT. THIS SCENARIO SUGGESTS
THUNDERSTORM CHANCES FRIDAY NIGHT...WITH MOSTLY SMALL POPS AND
MAINLY ACROSS THE SOUTH...THEREAFTER. HAD TO TINKER ABOUT WITH
REGIONAL ALLBLEND TO REFLECT THAT. THIS FAMILIAR RECENT PATTERN ALSO
STRONGLY SUGGESTS BELOW NORMAL TEMPERATURES ONCE AGAIN. REGIONAL
INITIALIZATION HAD A GOOD HANDLE ON THAT.
&&
.AVIATION /DISCUSSION FOR 141800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT SUN JUL 14 2013
MVFR CEILINGS LOOK LIKE THEY PERSIST ALL DAY PER MODEL
SOUNDINGS...CONVECTIVE CONDENSATION LEVELS AND CU DEVELOPMENT PROGS.
HOWEVER...WOULD NOT RULE OUT CEILINGS TO 3500 FEET AFTER 20Z IF ANY
BREAKS OCCUR IN THE OVERCAST. OTHERWISE...SHOULD BE DRY UNTIL AFTER
00Z. THEN...ILL-DEFINED WARM FRONT IS EXPECTED TO MOVE THROUGH AFTER
04Z. WOULD NOT RULE OUT STORMS ALONG AND AHEAD OF THE WARM
FRONT...HOWEVER WITH CONVERGENCE WEAK...AND LITTLE GOING ON NOW
AHEAD OF THE FRONT...WILL LEAVE OUT MENTION OF THUNDER OVERNIGHT AND
JUST GO WITH VCTS AFTER 20Z WEDNESDAY AT IND ASSOCIATED WITH A COLD
FRONT APPROACHING FROM THE NORTHWEST.
SOUTH AND SOUTHWEST WINDS WILL BE 10 KNOTS OR LESS THROUGH THE
PERIOD. FINALLY...WILL THROW IN MVFR FOG AFTER 09Z AS DEW POINTS
INCREASE TO AROUND 70 BEHIND THE WARM FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...CP
SHORT TERM...PUMA
LONG TERM....MK
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
100 PM EDT TUE AUG 6 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 243 AM EDT TUE AUG 6 2013
WARMER AIR IS SET TO ARRIVE IN INDIANA TODAY AS HIGH PRESSURE OVER
THE EAST COAST PROVIDES A WARMER AND MORE HUMID SOUTHERLY FLOW
ALONG WITH DRY WEATHER. A MORE ACTIVE WEATHER PATTERN WILL TAKE
SHAPE THROUGH THE MIDDLE OF THE WEEK AS A COLD FRONT IS EXPECTED
TO PUSH TOWARD INDIANA LATE TONIGHT AND STALL ACROSS SOUTHERN
INDIANA THROUGH THURSDAY THE FRONT WILL BRING CHANCES FOR SHOWERS
AND STORMS FROM LATE TONIGHT THROUGH FRIDAY.
HIGH PRESSURE IS EXPECTED TO ARRIVE LATE FRIDAY AND BRING A RETURN
TO DRY WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 944 AM EDT TUE AUG 6 2013
BUMPED UP CLOUD COVER THIS MORNING DUE TO SATELLITE TRENDS AS LOW
DECK HAS BEEN OVERSPREADING THE AREA. LOOKS LIKE IT WILL TAKE A
BIT LONGER TO SCATTER OUT AND THUS TRENDED MOSTLY CLOUDY TO LAST
THROUGH MID AFTERNOON FOR MOST OF THE AREA. WITH THIS INCREASE IN
CLOUD COVER HAVE ALSO LOWER HIGH TEMPERATURES FOR THE DAY...ONLY
BY A DEGREE OR SO IN THE NORTH AND CENTRAL BUT BY A FEW DEGREES IN
THE SOUTHWEST SINCE DEBRIS CLOUDS WILL LIKELY KEEP THAT AREA
MOSTLY CLOUDY THROUGH MUCH OF THE DAY. RAP SHOWS SOME ISOLATED TO
SCATTERED CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON BUT OTHER
MODELS STILL LOOK DRY. WITH SOME SUBSIDENCE AND DRY AIR ALOFT AND
THE RAP ALSO SHOWING SOME THINGS NOW THAT ARE NOT OCCURRING WILL
CONTINUE WITH DRY FORECAST THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 243 AM EDT TUE AUG 6 2013
MAIN FOCUS DURING THIS PERIOD WILL BE POPS.
MODELS ARE IN PRETTY GOOD AGREEMENT OF THE OVERALL TREND OF A
WET...ACTIVE PATTERN.
GFS AND NAM BOTH SUGGEST THE FIRST SHORT WAVE ARRIVING IN THE AREA
LATE TONIGHT AMID THE NW FLOW ALOFT. FORECAST SOUNDINGS HINT AT A
SLOW TOP DOWN STYLE SATURATION BY 12Z. THUS WILL KEEP THE EVENING
DRY...BUT TREND TOWARD HIGHER CHANCES FOR RAIN DURING THE
OVERNIGHT HOURS. 310K GFS ISENTROPIC SURFACE ALSO SHOWS A GOOD
SURGE OF ISENTROPIC LIFT WITH SPECIFIC HUMIDITIES RISING TO NEAR
8 G/KG. WILL TREND LOWS AT OR ABOVE MAVMOS VALUES DUE TO EXPECTED
WARM AIR ADVECTION...CLOUDS...AND PRECIP.
ON WEDNESDAY MORNING...THE GFS AND NAM SUGGEST A COLD FRONT
TROUGH LINGERING ACROSS THE STATE AS THE UPPER SUPPORT FROM THE
OVERNIGHT PERIOD DEPARTS. FORECAST SOUNDINGS SUGGEST DRYING
OUT...HOWEVER PLENTY OF CAPE...IN EXCESS OF 2000 J/KG REMAINS
AVAILABLE. PWATS ARE ALSO NEAR 1.75 INCHES...VERY MOIST. CONVECTIVE
TEMPS ON WEDNESDAY AFTERNOON ARE VERY ATTAINABLE...IN THE LOWER
80S...AND THE GFS 310K ISENTROPIC SURFACE SHOWS STRONG LIFT WITH
AGAIN A VERY MOIST AIR MASS WITH SPECIFIC HUMIDITIES OVER 9 G/KG.
MEANWHILE AT THE SURFACE A WARM FRONT STALLS ACROSS SOUTHERN
INDIANA...FURTHER ACTING AS A FOCUS FOR LOWER LEVEL CONVERGENCE.
THUS ANY HEATING ON WEDNESDAY SHOULD LEAD TO DEVELOPMENT. WILL
TREND POPS AT OR ABOVE MAVMOS...PARTICULARLY DURING THE AFTERNOON.
GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND HIGHS AT OR BELOW
MAVMOS.
GFS DEPICTS A SHORT WAVE RIDING ACROSS THE WARM FRONT ACROSS THE
SOUTHERN PARTS OF THE FORECAST AREA ON WEDNESDAY NIGHT...AGAIN A
VERY WARM AND MOIST AIR MASS WILL REMAIN IN PLACE. FORECAST
SOUNDINGS ACROSS THE AREA ALSO INDICATE DEEP SATURATION BY
THURSDAY...AND NOW WITH PWATS IN EXCESS OF 2 INCHES. FAVORABLE
CAPE IS ALSO AVAILABLE. ALOFT IT APPEARS AS IF THE TROPICAL PLUME
THAT IS CURRENTLY FLOWING ACROSS THE PLAINS INTO THE DEEP SOUTH WILL
SHIFT EAST BY WEDNESDAY AND THURSDAY...ALLOWING THIS DEEPER
MOISTURE TO SURGE INTO INDIANA AND THE OHIO VALLEY...PARTICULARLY
ACROSS THE SOUTHERN PARTS OF OUR STATE. THUS WILL CONTINUE TO
RAISE POPS THROUGH THURSDAY NIGHT...TRENDING HIGHS COOLER THAN
MAVMOS AND LOWS WARMER...GIVEN THE EXPECTED CLOUDS AND RAIN.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 223 AM EDT TUE AUG 6 2013
LONG TERM PERIOD WILL BE CHARACTERIZED BY ZONAL OR WEAKLY CYCLONIC
FLOW...WITH SURFACE HIGH PRESSURE LIKELY TO BE IN CONTROL ACROSS
THE AREA FROM THE WEEKEND ONWARD. FRONTAL BOUNDARY WILL BE
GRADUALLY EXITING THE REGION EARLY IN THE PERIOD...AND WILL
CONTINUE TO CARRY POPS FRIDAY AND FRIDAY NIGHT BEFORE GOING DRY
THE REST OF THE PERIOD. ALLBLEND WANTS TO INSERT POPS LATE IN THE
WEEKEND BUT AT THIS POINT MODELS LOOK OVERAGGRESSIVE FOR THE WEAK
FEATURES NOTED WELL UPSTREAM.
ZONAL TO WEAKLY CYCLONIC FLOW SUGGESTS TEMPS NEAR TO A BIT BELOW
NORMAL...AND ALLBLEND HANDLED THIS WELL WITH FEW TWEAKS REQUIRED.
&&
.AVIATION /DISCUSSION FOR 141800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT SUN JUL 14 2013
MVFR CEILINGS LOOK LIKE THEY PERSIST ALL DAY PER MODEL
SOUNDINGS...CONVECTIVE CONDENSATION LEVELS AND CU DEVELOPMENT PROGS.
HOWEVER...WOULD NOT RULE OUT CEILINGS TO 3500 FEET AFTER 20Z IF ANY
BREAKS OCCUR IN THE OVERCAST. OTHERWISE...SHOULD BE DRY UNTIL AFTER
00Z. THEN...ILL-DEFINED WARM FRONT IS EXPECTED TO MOVE THROUGH AFTER
04Z. WOULD NOT RULE OUT STORMS ALONG AND AHEAD OF THE WARM
FRONT...HOWEVER WITH CONVERGENCE WEAK...AND LITTLE GOING ON NOW
AHEAD OF THE FRONT...WILL LEAVE OUT MENTION OF THUNDER OVERNIGHT AND
JUST GO WITH VCTS AFTER 20Z WEDNESDAY AT IND ASSOCIATED WITH A COLD
FRONT APPROACHING FROM THE NORTHWEST.
SOUTH AND SOUTHWEST WINDS WILL BE 10 KNOTS OR LESS THROUGH THE
PERIOD. FINALLY...WILL THROW IN MVFR FOG AFTER 09Z AS DEW POINTS
INCREASE TO AROUND 70 BEHIND THE WARM FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...CP
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1014 AM EDT TUE AUG 6 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 243 AM EDT TUE AUG 6 2013
WARMER AIR IS SET TO ARRIVE IN INDIANA TODAY AS HIGH PRESSURE OVER
THE EAST COAST PROVIDES A WARMER AND MORE HUMID SOUTHERLY FLOW
ALONG WITH DRY WEATHER. A MORE ACTIVE WEATHER PATTERN WILL TAKE
SHAPE THROUGH THE MIDDLE OF THE WEEK AS A COLD FRONT IS EXPECTED
TO PUSH TOWARD INDIANA LATE TONIGHT AND STALL ACROSS SOUTHERN
INDIANA THROUGH THURSDAY THE FRONT WILL BRING CHANCES FOR SHOWERS
AND STORMS FROM LATE TONIGHT THROUGH FRIDAY.
HIGH PRESSURE IS EXPECTED TO ARRIVE LATE FRIDAY AND BRING A RETURN
TO DRY WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 944 AM EDT TUE AUG 6 2013
BUMPED UP CLOUD COVER THIS MORNING DUE TO SATELLITE TRENDS AS LOW
DECK HAS BEEN OVERSPREADING THE AREA. LOOKS LIKE IT WILL TAKE A
BIT LONGER TO SCATTER OUT AND THUS TRENDED MOSTLY CLOUDY TO LAST
THROUGH MID AFTERNOON FOR MOST OF THE AREA. WITH THIS INCREASE IN
CLOUD COVER HAVE ALSO LOWER HIGH TEMPERATURES FOR THE DAY...ONLY
BY A DEGREE OR SO IN THE NORTH AND CENTRAL BUT BY A FEW DEGREES IN
THE SOUTHWEST SINCE DEBRIS CLOUDS WILL LIKELY KEEP THAT AREA
MOSTLY CLOUDY THROUGH MUCH OF THE DAY. RAP SHOWS SOME ISOLATED TO
SCATTERED CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON BUT OTHER
MODELS STILL LOOK DRY. WITH SOME SUBSIDENCE AND DRY AIR ALOFT AND
THE RAP ALSO SHOWING SOME THINGS NOW THAT ARE NOT OCCURRING WILL
CONTINUE WITH DRY FORECAST THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 243 AM EDT TUE AUG 6 2013
MAIN FOCUS DURING THIS PERIOD WILL BE POPS.
MODELS ARE IN PRETTY GOOD AGREEMENT OF THE OVERALL TREND OF A
WET...ACTIVE PATTERN.
GFS AND NAM BOTH SUGGEST THE FIRST SHORT WAVE ARRIVING IN THE AREA
LATE TONIGHT AMID THE NW FLOW ALOFT. FORECAST SOUNDINGS HINT AT A
SLOW TOP DOWN STYLE SATURATION BY 12Z. THUS WILL KEEP THE EVENING
DRY...BUT TREND TOWARD HIGHER CHANCES FOR RAIN DURING THE
OVERNIGHT HOURS. 310K GFS ISENTROPIC SURFACE ALSO SHOWS A GOOD
SURGE OF ISENTROPIC LIFT WITH SPECIFIC HUMIDITIES RISING TO NEAR
8 G/KG. WILL TREND LOWS AT OR ABOVE MAVMOS VALUES DUE TO EXPECTED
WARM AIR ADVECTION...CLOUDS...AND PRECIP.
ON WEDNESDAY MORNING...THE GFS AND NAM SUGGEST A COLD FRONT
TROUGH LINGERING ACROSS THE STATE AS THE UPPER SUPPORT FROM THE
OVERNIGHT PERIOD DEPARTS. FORECAST SOUNDINGS SUGGEST DRYING
OUT...HOWEVER PLENTY OF CAPE...IN EXCESS OF 2000 J/KG REMAINS
AVAILABLE. PWATS ARE ALSO NEAR 1.75 INCHES...VERY MOIST. CONVECTIVE
TEMPS ON WEDNESDAY AFTERNOON ARE VERY ATTAINABLE...IN THE LOWER
80S...AND THE GFS 310K ISENTROPIC SURFACE SHOWS STRONG LIFT WITH
AGAIN A VERY MOIST AIR MASS WITH SPECIFIC HUMIDITIES OVER 9 G/KG.
MEANWHILE AT THE SURFACE A WARM FRONT STALLS ACROSS SOUTHERN
INDIANA...FURTHER ACTING AS A FOCUS FOR LOWER LEVEL CONVERGENCE.
THUS ANY HEATING ON WEDNESDAY SHOULD LEAD TO DEVELOPMENT. WILL
TREND POPS AT OR ABOVE MAVMOS...PARTICULARLY DURING THE AFTERNOON.
GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND HIGHS AT OR BELOW
MAVMOS.
GFS DEPICTS A SHORT WAVE RIDING ACROSS THE WARM FRONT ACROSS THE
SOUTHERN PARTS OF THE FORECAST AREA ON WEDNESDAY NIGHT...AGAIN A
VERY WARM AND MOIST AIR MASS WILL REMAIN IN PLACE. FORECAST
SOUNDINGS ACROSS THE AREA ALSO INDICATE DEEP SATURATION BY
THURSDAY...AND NOW WITH PWATS IN EXCESS OF 2 INCHES. FAVORABLE
CAPE IS ALSO AVAILABLE. ALOFT IT APPEARS AS IF THE TROPICAL PLUME
THAT IS CURRENTLY FLOWING ACROSS THE PLAINS INTO THE DEEP SOUTH WILL
SHIFT EAST BY WEDNESDAY AND THURSDAY...ALLOWING THIS DEEPER
MOISTURE TO SURGE INTO INDIANA AND THE OHIO VALLEY...PARTICULARLY
ACROSS THE SOUTHERN PARTS OF OUR STATE. THUS WILL CONTINUE TO
RAISE POPS THROUGH THURSDAY NIGHT...TRENDING HIGHS COOLER THAN
MAVMOS AND LOWS WARMER...GIVEN THE EXPECTED CLOUDS AND RAIN.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 223 AM EDT TUE AUG 6 2013
LONG TERM PERIOD WILL BE CHARACTERIZED BY ZONAL OR WEAKLY CYCLONIC
FLOW...WITH SURFACE HIGH PRESSURE LIKELY TO BE IN CONTROL ACROSS
THE AREA FROM THE WEEKEND ONWARD. FRONTAL BOUNDARY WILL BE
GRADUALLY EXITING THE REGION EARLY IN THE PERIOD...AND WILL
CONTINUE TO CARRY POPS FRIDAY AND FRIDAY NIGHT BEFORE GOING DRY
THE REST OF THE PERIOD. ALLBLEND WANTS TO INSERT POPS LATE IN THE
WEEKEND BUT AT THIS POINT MODELS LOOK OVERAGGRESSIVE FOR THE WEAK
FEATURES NOTED WELL UPSTREAM.
ZONAL TO WEAKLY CYCLONIC FLOW SUGGESTS TEMPS NEAR TO A BIT BELOW
NORMAL...AND ALLBLEND HANDLED THIS WELL WITH FEW TWEAKS REQUIRED.
&&
.AVIATION /UPDATED DISCUSSION FOR TAFS/...
ISSUED AT 958 AM EDT TUE AUG 6 2013
WILL EXTEND DURATION OF MVFR CLOUD DECKS AT ALL TAF SITES A LITTLE
LONGER INTO THE AFTERNOON BASED ON OBSERVED DECKS REMAINING FAIRLY
SOLID. ALSO SOUNDING FORECASTS KEEPING VERY SHALLOW BUT NEARLY
SATURATED LAYER THAT SLOWLY LIFTS TO NEAR 3000 FEET WITH HEATING.
KHUF ALSO FLIRTING WITH IFR CLOUD DECKS THAT ARE OVER ILLINOIS AND
TRYING TO SPREAD EAST. KLAF SHOULD REMAIN ABOVE 1000 FT DECKS
GIVEN ADJACENT ILLINOIS OBSERVATIONS. KIND AND KBMG SHOULD ALSO
REMAIN ABOVE 1000 FT AND THREAT TIME...IF ANY WOULD BE THROUGH
061500Z.
PREVIOUS DISCUSSION ISSUED AT 638 AM EDT TUE AUG 6 2013...
MVFR CEILINGS LIKELY TO PERSIST AT TIMES THROUGH MIDDAY TODAY. VFR
BEYOND THEN.
MVFR CEILINGS HAVE MOVED EASTWARD ACROSS THE AREA AND GUIDANCE HANGS
ONTO THEM THROUGH AT LEAST MIDDAY. THIS APPEARS REASONABLE AND SREF
PROBABILITIES AGREE. WILL INSERT TEMPO SCATTERED GROUPS LATER IN THE
MORNING AS THE CEILINGS WILL LIKELY BEGIN TO FLUCTUATE AS THEY LIFT.
MAINLY MID CLOUD BEYOND THIS MORNING. SOME SHOWERS/STORMS POSSIBLE
TONIGHT BUT FAIRLY UNCERTAIN AT THIS POINT...SO WILL LEAVE FOR LATER
PACKAGES.
WINDS WILL BE BELOW 10KT THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...CP
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...TUCEK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
951 AM EDT TUE AUG 6 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 243 AM EDT TUE AUG 6 2013
WARMER AIR IS SET TO ARRIVE IN INDIANA TODAY AS HIGH PRESSURE OVER
THE EAST COAST PROVIDES A WARMER AND MORE HUMID SOUTHERLY FLOW
ALONG WITH DRY WEATHER. A MORE ACTIVE WEATHER PATTERN WILL TAKE
SHAPE THROUGH THE MIDDLE OF THE WEEK AS A COLD FRONT IS EXPECTED
TO PUSH TOWARD INDIANA LATE TONIGHT AND STALL ACROSS SOUTHERN
INDIANA THROUGH THURSDAY THE FRONT WILL BRING CHANCES FOR SHOWERS
AND STORMS FROM LATE TONIGHT THROUGH FRIDAY.
HIGH PRESSURE IS EXPECTED TO ARRIVE LATE FRIDAY AND BRING A RETURN
TO DRY WEATHER FOR THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 944 AM EDT TUE AUG 6 2013
BUMPED UP CLOUD COVER THIS MORNING DUE TO SATELLITE TRENDS AS LOW
DECK HAS BEEN OVERSPREADING THE AREA. LOOKS LIKE IT WILL TAKE A
BIT LONGER TO SCATTER OUT AND THUS TRENDED MOSTLY CLOUDY TO LAST
THROUGH MID AFTERNOON FOR MOST OF THE AREA. WITH THIS INCREASE IN
CLOUD COVER HAVE ALSO LOWER HIGH TEMPERATURES FOR THE DAY...ONLY
BY A DEGREE OR SO IN THE NORTH AND CENTRAL BUT BY A FEW DEGREES IN
THE SOUTHWEST SINCE DEBRIS CLOUDS WILL LIKELY KEEP THAT AREA
MOSTLY CLOUDY THROUGH MUCH OF THE DAY. RAP SHOWS SOME ISOLATED TO
SCATTERED CONVECTIVE DEVELOPMENT LATER THIS AFTERNOON BUT OTHER
MODELS STILL LOOK DRY. WITH SOME SUBSIDENCE AND DRY AIR ALOFT AND
THE RAP ALSO SHOWING SOME THINGS NOW THAT ARE NOT OCCURRING WILL
CONTINUE WITH DRY FORECAST THROUGH THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
ISSUED AT 243 AM EDT TUE AUG 6 2013
MAIN FOCUS DURING THIS PERIOD WILL BE POPS.
MODELS ARE IN PRETTY GOOD AGREEMENT OF THE OVERALL TREND OF A
WET...ACTIVE PATTERN.
GFS AND NAM BOTH SUGGEST THE FIRST SHORT WAVE ARRIVING IN THE AREA
LATE TONIGHT AMID THE NW FLOW ALOFT. FORECAST SOUNDINGS HINT AT A
SLOW TOP DOWN STYLE SATURATION BY 12Z. THUS WILL KEEP THE EVENING
DRY...BUT TREND TOWARD HIGHER CHANCES FOR RAIN DURING THE
OVERNIGHT HOURS. 310K GFS ISENTROPIC SURFACE ALSO SHOWS A GOOD
SURGE OF ISENTROPIC LIFT WITH SPECIFIC HUMIDITIES RISING TO NEAR
8 G/KG. WILL TREND LOWS AT OR ABOVE MAVMOS VALUES DUE TO EXPECTED
WARM AIR ADVECTION...CLOUDS...AND PRECIP.
ON WEDNESDAY MORNING...THE GFS AND NAM SUGGEST A COLD FRONT
TROUGH LINGERING ACROSS THE STATE AS THE UPPER SUPPORT FROM THE
OVERNIGHT PERIOD DEPARTS. FORECAST SOUNDINGS SUGGEST DRYING
OUT...HOWEVER PLENTY OF CAPE...IN EXCESS OF 2000 J/KG REMAINS
AVAILABLE. PWATS ARE ALSO NEAR 1.75 INCHES...VERY MOIST. CONVECTIVE
TEMPS ON WEDNESDAY AFTERNOON ARE VERY ATTAINABLE...IN THE LOWER
80S...AND THE GFS 310K ISENTROPIC SURFACE SHOWS STRONG LIFT WITH
AGAIN A VERY MOIST AIR MASS WITH SPECIFIC HUMIDITIES OVER 9 G/KG.
MEANWHILE AT THE SURFACE A WARM FRONT STALLS ACROSS SOUTHERN
INDIANA...FURTHER ACTING AS A FOCUS FOR LOWER LEVEL CONVERGENCE.
THUS ANY HEATING ON WEDNESDAY SHOULD LEAD TO DEVELOPMENT. WILL
TREND POPS AT OR ABOVE MAVMOS...PARTICULARLY DURING THE AFTERNOON.
GIVEN THE EXPECTED CLOUDS AND RAIN...WILL TREND HIGHS AT OR BELOW
MAVMOS.
GFS DEPICTS A SHORT WAVE RIDING ACROSS THE WARM FRONT ACROSS THE
SOUTHERN PARTS OF THE FORECAST AREA ON WEDNESDAY NIGHT...AGAIN A
VERY WARM AND MOIST AIR MASS WILL REMAIN IN PLACE. FORECAST
SOUNDINGS ACROSS THE AREA ALSO INDICATE DEEP SATURATION BY
THURSDAY...AND NOW WITH PWATS IN EXCESS OF 2 INCHES. FAVORABLE
CAPE IS ALSO AVAILABLE. ALOFT IT APPEARS AS IF THE TROPICAL PLUME
THAT IS CURRENTLY FLOWING ACROSS THE PLAINS INTO THE DEEP SOUTH WILL
SHIFT EAST BY WEDNESDAY AND THURSDAY...ALLOWING THIS DEEPER
MOISTURE TO SURGE INTO INDIANA AND THE OHIO VALLEY...PARTICULARLY
ACROSS THE SOUTHERN PARTS OF OUR STATE. THUS WILL CONTINUE TO
RAISE POPS THROUGH THURSDAY NIGHT...TRENDING HIGHS COOLER THAN
MAVMOS AND LOWS WARMER...GIVEN THE EXPECTED CLOUDS AND RAIN.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ISSUED AT 223 AM EDT TUE AUG 6 2013
LONG TERM PERIOD WILL BE CHARACTERIZED BY ZONAL OR WEAKLY CYCLONIC
FLOW...WITH SURFACE HIGH PRESSURE LIKELY TO BE IN CONTROL ACROSS
THE AREA FROM THE WEEKEND ONWARD. FRONTAL BOUNDARY WILL BE
GRADUALLY EXITING THE REGION EARLY IN THE PERIOD...AND WILL
CONTINUE TO CARRY POPS FRIDAY AND FRIDAY NIGHT BEFORE GOING DRY
THE REST OF THE PERIOD. ALLBLEND WANTS TO INSERT POPS LATE IN THE
WEEKEND BUT AT THIS POINT MODELS LOOK OVERAGGRESSIVE FOR THE WEAK
FEATURES NOTED WELL UPSTREAM.
ZONAL TO WEAKLY CYCLONIC FLOW SUGGESTS TEMPS NEAR TO A BIT BELOW
NORMAL...AND ALLBLEND HANDLED THIS WELL WITH FEW TWEAKS REQUIRED.
&&
.AVIATION /DISCUSSION FOR THE 06/12Z TAFS/...
ISSUED AT 638 AM EDT TUE AUG 6 2013
MVFR CEILINGS LIKELY TO PERSIST AT TIMES THROUGH MIDDAY TODAY. VFR
BEYOND THEN.
MVFR CEILINGS HAVE MOVED EASTWARD ACROSS THE AREA AND GUIDANCE HANGS
ONTO THEM THROUGH AT LEAST MIDDAY. THIS APPEARS REASONABLE AND SREF
PROBABILITIES AGREE. WILL INSERT TEMPO SCATTERED GROUPS LATER IN THE
MORNING AS THE CEILINGS WILL LIKELY BEGIN TO FLUCTUATE AS THEY LIFT.
MAINLY MID CLOUD BEYOND THIS MORNING. SOME SHOWERS/STORMS POSSIBLE
TONIGHT BUT FAIRLY UNCERTAIN AT THIS POINT...SO WILL LEAVE FOR LATER
PACKAGES.
WINDS WILL BE BELOW 10KT THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...CP
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...NIELD
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AREA FORECAST DISCUSSION
NWS TOPEKA KS
951 PM CDT Wed Aug 7 2013
.UPDATE...
Issued at 940 PM CDT WED AUG 7 2013
Increase pops based on the new runs the HRRR model. The HRRR did a
good job last night forecasting the outflow boundary propagating northeast
off the MCS and causing numerous showers and thunderstorms to
develop farther north along and and south of the boundary, from
the southern counties to north of I-70.
The greatest potential for likely
to categorical pops will remain across the southern counties with
a sharp gradient in pops from east central KS, along I-70 into
north central KS along the NE border. Northeast KS may not see any
rainfall until Thursday afternoon. Also increased pops for the southern
CWA into Thursday morning as the brunt of MCS will move across southeast
KS and the northern fringe may cause heavy rainfall across the
extreme southeast counties.
&&
.SHORT TERM...(THIS EVENING THROUGH Thursday)
ISSUED AT 331 PM CDT WED AUG 7 2013
Extensive cloud cover has kept high temperatures today mainly in
upper 70s to lower to middle 80s across the area. Diffuse boundary
has been draped E to W across the area but is difficult to find
because of very weak surface wind fields. Isolated brief showers
have popped up and quickly died where greater instability exists,
near and south of boundary. Wouldn`t expect this activity to be
more than isolated late this afternoon and evening with weak
convergence and no organized upper support.
Nearly all short range (and medium range) models now consistent in
keeping weak upper disturbance south of area, so most of northeast
quarter of KS dry overnight. Only outlier is now the 09Z SREF, and
have disregarded that in coming up with POP and QPF forecast. Thus,
have considerably decreased previous forecast POPs for tonight with
highest values across far south and west forecast area and least in
far northeast KS. Latest model runs also increase influence of
surface high pressure nosing into area from the upper
midwest/western Great Lakes. This will also inhibit chances for
thunderstorms on Thursday as well, with best chances still south and
west and lowest chances northeast. With this guidance, would not
expect any significantly heavy precipitation and very low chances
for any new flooding, or increase on current river flooding through
Thursday.
.LONG TERM...(Thursday NIGHT THROUGH Wednesday)
ISSUED AT 331 PM CDT WED AUG 7 2013
Thursday evening through Saturday...
On Thursday evening, widespread moderate to at times heavy rainfall
is expected to spread northeast through the cwa. Weak mid level flow
will allow a slow northeast progression of the main shortwave trof
and therefore prolonged duration of scattered showers and
thunderstorms in the area. Strong southerly fetch of moisture
combined with warm air overriding the h85 front is expected to
center heaviest rainfall along and just north of the axis. Latest
model runs of the GFS and NAM are beginning to focus higher qpf
values just south and east of the cwa. This will need to be
monitored for consistency in consideration of flood potential. Areas
especially south of Interstate 70 who have persistently seen
rainfall each evening and/or have had flooding issues need to be
most aware to flash flooding potential from Thursday evening into
Friday. Based on the uncertainty mentioned will defer issuing flood
watch until next issuance. Where heavy precip does develop forecast
soundings depict completely saturated columns during this period
with pwat values extending above 2 inches. Showers and thunderstorms
should gradually exit the area through the day on Friday before
surface high builds southward Friday evening. Cloud cover gradually
clearing out with exiting showers should hold temps to the upper 70s
and low 80s on Friday. Light northeast winds hover around 10 mph.
Ridge flattens out Saturday with mid level zonal flow keeping most
of the rain showers out of the area. Cool air advection filtering
southward on the backside of the cool front will keep highs quite
pleasant for August in the low 80s. Slightly drier air accompanying
the wave should alleviate dewpoints a bit into the low 60s. The 12Z
NAM and ECMWF try to redevelop scattered convection over east
central areas during the late aftn in vcnty of the frontal boundary.
With this being the only run will keep forecast dry for now and
monitor model trends in upcoming forecasts.
Saturday evening through Wednesday...
On Sunday an upper trof begins to deepen across the Ontario region.
A series of embedded waves will continue to bring off and on showers
and thunderstorm chances. GFS has pretty consistent between each run
by carrying southward a sfc trough and complex of showers and
thunderstorms southeast Sunday evening into Monday. Frontal boundary
accompanying the trough becomes nearly stationary over central
Kansas with a similar pattern for precip chances through Wednesday.
Confidence is not high after Monday as the 12Z ECMWF has been
inconsistent with the frontal boundary positioning well south of
the cwa and therefore keeping much of the period dry. Temperatures
while progged to be slightly warmer will largely depend on rainfall
and cloud cover. For now will keep highs in the low to mid 80s with
lows in the 60s.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z Thursday EVENING)
ISSUED AT 620 PM CDT WED AUG 7 2013
Most numerical models are showing thunderstorms remaining west and
south of the TAF sites through most of the TAF period. At this
time I do not have confidence to insert VCTS into TAFS. Kept TAFS
VFR through next 24 hours. CU may develop once again Thursday afternoon
with bases of 6 to 8 thousand feet.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Gargan
SHORT TERM...PHILLIPS
LONG TERM...BOWEN
AVIATION...GARGAN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
523 PM MDT WED AUG 7 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM MDT WED AUG 7 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS INDICATES ZONAL FLOW STILL IN
PLACE ACROSS THE CONUS WITH STRONG CLOSED LOW OVER CENTRAL CANADA.
AN EMBEDDED H5/H7 LOW IN IN PLACE UPSTREAM OF THE CWA OVER THE FOUR
CORNER REGION.
LARGE SCALE FORCING AND MID LEVEL MOISTURE CONTINUE TO ADVECT INTO
THE CWA FROM THE SOUTHWEST AHEAD OF THE FOUR CORNERS TROUGH. RAP
ANALYSIS STILL SHOWS 500-1500 J/KG OF MUCAPE IN PLACE...SO
THUNDERSTORMS ARE CERTAINLY POSSIBLE. AT THIS POINT OVERALL THREAT
FOR SEVERE THUNDERSTORMS SEEMS LOW. MODELS CONTINUE TO PAIN BULLS EYE
OF 0.50+ QPF...FAVORING SOUTHERN LOCATIONS. AT THE SAME
TIME...NAM/SREF HAVE TRENDED FURTHER NORTH WHICH DOES SEEM TO HAVE
SUPPORT LOOKING AT LATEST RADAR TRENDS. I ADJUSTED POPS ACCORDINGLY.
RAP INDICATES PWATS IN EXCESS OF 1.3"...AND WHILE LOWER THAN THE LAST
FEW DAYS IS STILL CLIMATOLOGICALLY HIGH. BASED ON RADAR/SATELLITE
TRENDS...AND THE NATURE OF THIS PATTERN...I AM CURRENTLY EXPECTING
SEVERAL PERIODS OF SHOWERS/THUNDERSTORMS ROTATING ACROSS OUR CWA
THROUGH TONIGHT...BEFORE THE MAIN TROUGH MOVES ACROSS THE REGION. AS
THIS OCCURS WE MIGHT SEE OUR BEST CHANCE FOR HEAVY PRECIP ACROSS
MOST OF THE CWA. THERE IS STILL SOME INDICATION THIS COULD OCCUR
LATER IN THE DAY THURSDAY...HOWEVER CONSENSUS SUPPORTS A MORNING
TROUGH PASSAGE AND DECREASING CHANCES THROUGH MIDDAY THURSDAY.
REGARDING WATCH...CONSIDERING THE LIKELIHOOD THAT PRECIPITATION WILL
REMAIN LIGHT TO MODERATE ACROSS MOST OF THE AREA WITH HIGHEST
TOTALS SPREAD OUT OVER 6-12HR PERIOD...I AM STARTING TO QUESTION
THE POTENTIAL FOR FLASH FLOODING. LATEST 6HR FLASH FLOOD GUIDANCE IS
GENERALLY IN THE 2-3 INCH RANGE OVER THE WATCH AREA AND UNLESS WE CAN
GET A STRONG THUNDERSTORM EMBEDDED WITHIN THE LARGER AREA OF
LIGHT-MODERATE RAIN IM NOT SURE WE WILL SEE THESE RATES. WE MAY BE
ABLE TO CANCEL THE WATCH LATER THIS EVENING...BUT I WOULD RATHER
WAIT AND SEE HOW CONVECTION EVOLVES.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 221 PM MDT WED AUG 7 2013
THURSDAY EVENING THE UPPER LEVEL SHORT WAVE TROUGH WILL MOVE EAST OF
THE AREA. WITH THE NOSE OF THE LOW LEVEL JET OVER THE EASTERN PART
OF THE AREA AS WELL...AND A WEAK RIGHT ENTRANCE REGION OF THE 300MB
JET OVER THE AREA...THERE MAY BE SOME LINGERING PRECIP. ACTIVITY
AHEAD OF THE EXITING TROUGH. MEANWHILE BEHIND THE TROUGH DRIER AIR
WILL BE MOVING IN WHICH WILL CAUSE PRECIP. CHANCES TO DECLINE FROM
WEST TO EAST. HOWEVER WITH COOLER AIR MOVING IN THERE WILL BE SOME
INSTABILITY LINGERING BEHIND THE TROUGH. WITH SOME MUCH SMALLER
UPPER LEVEL DISTURBANCES MOVING THROUGH BEHIND THE MAIN
FEATURE...ISOLATED STORMS CANNOT BE RULED OUT DURING THE EVENING AND
INTO THE OVERNIGHT HOURS.
FRIDAY ANOTHER UPPER LEVEL SHORT WAVE TROUGH WILL DEVELOP OVER FAR
EASTERN COLORADO IN THE LATE AFTERNOON. AT THE SURFACE A TROUGH
WILL BE OVER THE WESTERN BORDER OF THE TRI-STATE AREA BENEATH THE
SHORT WAVE. WITH SURFACE CONVERGENCE AND UPPER LEVEL
LIFT...ANTICIPATE SOME STORMS DEVELOPING ALONG THE SURFACE TROUGH
DURING THE MID AFTERNOON INTO THE EARLY EVENING. MEAN STORM
MOTIONS WILL BE VERY SLOW...WITH MOTIONS TURNING FROM THE WEST TO
THE NORTH. THESE MOTIONS WILL KEEP THE STORMS CONFINED TO THE
SURFACE TROUGH. BY THE LATE EVENING ANY STORMS THAT DEVELOPED WILL
DISSIPATE AS THE ENVIRONMENT STABILIZES. THE MAIN THREAT WITH ANY
STORMS THAT DEVELOP WILL BE HEAVY RAINFALL.
SATURDAY THROUGH WEDNESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST
CONUS WILL SLOWLY BUILD NORTHWARD...WITH THE TRI-STATE AREA
REMAINING UNDER THE PERIPHERY OF THE RIDGE. AS A RESULT MULTIPLE
UPPER LEVEL SHORT WAVE TROUGHS WILL MOVE OVER THE AREA THROUGH THE
PERIOD. THE STRONGER TROUGHS WILL MOVE OVER THE AREA AFTER THE
WEEKEND. MEANWHILE A FRONT WILL WAFFLE BACK AND FORTH OVER THE
AREA DURING THIS PERIOD WHICH WILL CAUSE TEMPERATURES TO VARY
SOMEWHAT. AT THIS TIME RANGE DIFFICULT TO KNOW WHERE THE FRONT WILL
BE SO WILL KEEP THE CONSENSUS TEMP. FORECAST OF NEAR NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 520 PM MDT WED AUG 7 2013
A LARGE AREA OF PRECIPITATION CURRENTLY MOVING ACROSS NORTHEAST
COLORADO ASSOCIATED WITH AN UPPER DISTURBANCE WILL OVERSPREAD
B0TH KGLD AND KMCK THIS EVENING AND CONTINUE THROUGH THURSDAY
MORNING. FLIGHT CATEGORIES WILL GO DOWN WITH THE LOWERING CIGS AND
VISIBILITY RESTRICTIONS DUE TO RAIN AND/OR FOG...SLOW TO IMPROVE
THURSDAY MORNING THROUGH EARLY AFTERNOON. A FEW RUMBLES OF
THUNDER WILL ALSO BE POSSIBLE BUT SEVERE POTENTIAL LOOKS LIMITED
AT THIS TIME DUE TO COOL/STABLE AIR MASS IN THE AREA.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH UNTIL 11 PM MDT /MIDNIGHT CDT/ THIS EVENING
FOR KSZ027>029-041-042.
CO...FLASH FLOOD WATCH UNTIL 11 PM MDT THIS EVENING FOR COZ092.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
247 PM MDT TUE AUG 6 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE AUG 6 2013
LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE
ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER
TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY
MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES
ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN
THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE
TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER
TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS
FEATURE.
THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS
IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM
ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS
AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF
THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE
SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE
SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS
TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED
INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM
MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH
INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD
SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO
SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY
CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A
COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS
WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT.
WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE
KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW
ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE
ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS
ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY
BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR
CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT
HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF
THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES
WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS
COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A
FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND
WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO
CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS
AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH
ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN
FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 246 PM MDT TUE AUG 6 2013
FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT THE UPPER LEVEL WEATHER
PATTERN WILL REMAIN LARGELY UNCHANGED. AN UPPER LEVEL SHORT WAVE
TROUGH WILL MOVE OVER THE AREA WEDNESDAY NIGHT AND SLOWLY GLIDE
EASTWARD ACROSS THE AREA WITH ANOTHER ONE FOLLOWING IT OVER THE AREA
THURSDAY. WITH THE MID THROUGH UPPER LEVELS NEARLY TO TOTALLY
SATURATED AND THE RIGHT ENTRANCE OF THE 300MB JET OVER THE AREA AS
THESE TROUGHS MOVE THROUGH...AM THINKING THERE SHOULD BE A GOOD
CHANCE FOR SCATTERED TO WIDESPREAD RAINFALL DEVELOPMENT. THE BEST
AREA FOR PRECIP. CHANCES LOOKS TO BE OVER THE SOUTH HALF WHERE THE
BETTER FORCING AND LIFT WILL BE. PRECIP. CHANCES TAPER OFF THURSDAY
NIGHT FROM WEST TO EAST AS THE UPPER LEVEL TROUGH MOVES OUT OF THE
AREA AND DRIER AIR MOVES IN BEHIND IT. WEDNESDAY EVENING LOOKS TO
BE THE BEST CHANCE FOR SEVERE STORM DEVELOPMENT DUE TO 0-6KM SHEAR
OF 30-50KTS. HOWEVER ANY SEVERE STORMS THAT DEVELOP SHOULD REMAIN
CONFINED TO THE WESTERN AND SOUTHERN FRINGES OF THE AREA WHERE THE
BEST INSTABILITY WILL BE LOCATED. HEAVY RAINFALL WILL BE THE
PREDOMINANT THREAT DURING THIS TIMEFRAME DUE TO STORM MOTIONS OF
5-10KTS. A FLASH FLOOD WATCH WILL LIKELY BE NEEDED FROM WEDNESDAY
THROUGH THURSDAY MORNING FOR THE SOUTHERN TWO ROWS OF COUNTIES WHERE
STORM COVERAGE WILL BE MOST WIDESPREAD. AFTER SOME DISCUSSION WILL
HOLD OFF ISSUING THE WATCH FOR NOW TO PREVENT CONFUSION WITH ANY POTENTIAL
FLOODING THREAT FROM TODAY/S STORM ACTIVITY.
FOR FRIDAY THROUGH TUESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST
CONUS WILL BUILD A BIT FURTHER NORTH...WITH THE NORTHERN PERIPHARY
OF THE RIDGE OVER THE AREA. MULTIPLE UPPER LEVEL SHORT WAVE TROUGHS
WILL MOVE ACROSS THE AREA DURING THIS TIME CAUSING THERE TO BE
PRECIP. CHANCES FOR NEARLY EVERY DAY. MEANWHILE THE WEAK FRONT THAT
HAS BEEN WEST OF THE AREA WILL MOVE EAST ACROSS THE AREA DURING THE
WEEKEND INTO EARLY NEXT WEEK. AS A RESULT TEMPERATURES WILL RETURN
TO NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1144 AM MDT TUE AUG 6 2013
SCATTERED THUNDERSTORMS WILL DEVELOP ALONG TROUGH AXIS OVER NW
KS/SW NE THIS AFTERNOON AND INCREASE IN COVERAGE THROUGH THIS
EVENING AS THE ACTIVITY TRANSITIONS EAST. CURRENTLY COVERAGE IS
STILL TOO MUCH OF A QUESTION AT EITHER TERMINAL WITH BETTER
CHANCES FURTHER SOUTH AND EAST...SO I LIMITED MENTION TO VCTS.
LATE TONIGHT FOG/STRATUS IS EXPECTED TO REDEVELOP...WITH LOWER
CIGS/VIS AT BOTH TERMINALS BY SUNRISE. GUIDANCE CURRENTLY SUPPORTS
MVFR CONDITIONS...HOWEVER CONSIDERING THE MOIST NATURE OF THE
AIRMASS IF WINDS GO COMPLETELY CALM WE COULD SEE LOWER CONDITIONS
DEVELOP. FOR NOW I CHOSE TO STAY IN LINE WITH CURRENT
GUIDANCE...HOWEVER WE WILL NEED TO MONITOR THIS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
222 PM MDT TUE AUG 6 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 222 PM MDT TUE AUG 6 2013
LATEST WV IMAGERY AND RAP ANALYSIS SHOWS NW FLOW STILL IN PLACE
ACROSS THE NORTHERN AND CENTRAL CONUS...WITH A RIDGE CENTERED OVER
TEXAS AND A WEAKENED CLOSED LOW OVER SOUTHERN ARIZONA. A VERY
MOIST/UNSTABLE AIRMASS REMAINS IN PLACE OVER OUR CWA WITH TD VALUES
ACROSS NW KANSAS IN THE MID 60S TO LOW 70S...AND SB CAPE VALUES IN
THE 2000-4000 J/KG RANGE FROM THE WEST TO THE EAST. A SURFACE
TROUGH IS CURRENTLY CENTERED ALONG THE KS/CO BORDER...WITH LOWER
TD VALUES AND MUCH MORE STABLE AIRMASS TO THE WEST OF THIS
FEATURE.
THUNDERSTORMS HAVE ALREADY DEVELOPED ALONG THIS TROUGH AXIS
IN OUR FAR SW CWA. I WOULD EXPECT ADDITIONAL THUNDERSTORM
ACTIVITY TO INITIATE ALONG AND EAST OF THIS FEATURE THROUGH THIS
AFTERNOON AND EVENING. LATEST HRRR INDICATED ACTIVITY FORMING AHEAD OF
THIS AXIS AND FORMING INTO A CLUSTER/LINE AND SHIFTING TO THE
SOUTH AND EAST. BASED ON NAM/GFS SUPPORTING BETTER COVERAGE IN THE
SOUTH...WHICH IS IN LINE WITH SHORT RANGE GUIDANCE I KEPT THIS
TREND. A COLD FRONT WILL APPROACH THE CWA TONIGHT...WITH ELEVATED
INSTABILITY/GOOD MOISTURE LINGERING I DECIDED TO KEEP THUNDERSTORM
MENTION THROUGH THE NIGHT. CONSIDERING STORM MOTION WITH
INDIVIDUAL CELLS AND MOISTURE AVAILABILITY I AM CONCERNED WE COULD
SEE LOCALIZED FLASH FLOODING THIS AFTERNOON/EVENING IN ADDITION TO
SEVERE HAIL/WIND THREAT. COVERAGE IS A QUESTION THOUGH...WITH ANY
CLUSTER/LINE LIKELY BEGINNING TO PROPAGATE QUICKER AS IT FORMS A
COLD POOL IN OUR SOUTH. AS A RESULT WE MAY NOT ACTUALLY SEE AS
WIDESPREAD OF A THREAT OF FLASH FLOODING TODAY/TONIGHT.
WEDNESDAY...COLD FRONT WILL DROP SOUTH OF OUR CWA AND BE NEAR THE
KS/OK BORDER BY LATE WED AFTERNOON. DEEP MOIST EASTERLY FLOW
ALONG/NORTH OF THIS FEATURE COMBINED WITH INCREASING LARGE SCALE
ASCENT WILL SUPPORT NUMEROUS TO WIDESPREAD SHOWERS/THUNDERSTORMS
ACROSS OUR SOUTHERN CWA. I AM CONCERNED THAT THE BEST COVERAGE MAY
BE TIED TO THE FRONT...WHICH WOULD PUT BETTER COVERAGE SOUTH OF OUR
CWA. HOWEVER THERE IS ENOUGH MOISTURE/FORCING ALOFT TO SUPPORT
HIGHER POPS ACROSS OUR SOUTHERN CWA IN THE AFTERNOON. A RESULT OF
THICK CLOUD COVER AND CAA THROUGH THE DAY WILL BE HIGH TEMPERATURES
WELL BELOW NORMAL (UPPER 60S TO MID 70S). PREVIOUS FORECAST HAD THIS
COOLER TREND...SO ONLY MINOR ADJUSTMENTS MADE. WHILE WE MAY NEED A
FLASH FLOOD WATCH FOR WED AFTERNOON DUE TO POSSIBLE TRAINING AND
WIDESPREAD HEAVY RAIN COVERAGE IN THE SOUTH...I FELT IT WAS BEST TO
CONCENTRATE PUBLIC ATTENTION ON ONGOING THUNDERSTORMS THIS
AFTERNOON/EVENING TO AVOID CONFUSION. WE MAY NEED TO ISSUE A WATCH
ON OVERNIGHT SHIFTS IF IT LOOKS LIKE OUR SOUTHERN CWA WILL REMAIN
FAVORABLE FOR A LARGE SCALE FLASH FLOOD THREAT.
.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 220 AM MDT TUE AUG 6 2013
MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE SYNOPTIC
SCALE PATTERN DURING THE EXTENDED PERIOD. MINOR DIFFERENCES EMERGE
BY THE WEEKEND WHEN ECMWF IS STRONGER AND MORE AMPLIFIED THAN THE
GFS WITH UPPER RIDGE THAT BUILDS OVER OUR AREA. OTHERWISE...TYPICAL
DIFFERENCES EXIST WITH TIMING AND PLACEMENT OF SUBTLE SHORTWAVES IN
THE MID/UPPER FLOW LEADING TO UNCERTAINTY AS TO WHEN THE MOST
WIDESPREAD CONVECTION WILL OCCUR.
BY EARLY FRIDAY...DEEP MOISTURE WILL HAVE SHIFTED EAST OF THE AREA
AS RELATIVELY STRONG SHORTWAVE DEPARTS. COOL NORTHEASTERLY SURFACE
FLOW EARLY SHOULD SHIFT TO SOUTHEASTERLY LATE FRIDAY CAUSING A
RETURN OF LOW LEVEL MOISTURE AND HIGHER THETA-E VALUES. SOME
CONVECTION MAY DEVELOP FRIDAY AND FRIDAY EVENING IN THE VICINITY OF
LEE TROUGH / SURFACE CONVERGENCE OVER THE WESTERN PORTION OF THE
AREA. SIGNIFICANT FORCING IS ABSENT AND A RELATIVELY DRY COLUMN WITH
DEEP MIXED LAYER WILL LIKELY LIMIT COVERAGE OF CONVECTION. ON
SATURDAY...MOISTURE INCREASES FURTHER AND MID/UPPER FLOW
STRENGTHENS. LEE TROUGH SHARPENS AND MODELS INDICATE ONE OR TWO
SMALL PERTURBATIONS IN THE WESTERLY FLOW ALOFT...ALL OF WHICH
SUPPORTS A BETTER CHANCE OF CONVECTION ACROSS THE AREA. GFS IS MORE
PROGRESSIVE FOR SUNDAY AND MONDAY SHOWING DEEP MIXING ACROSS THE
WESTERN HALF OF THE AREA SUNDAY WITH CONVECTION CONFINED TO THE
EASTERN PORTION OF THE AREA WHERE BETTER MOISTURE RESIDES. ECMWF
HAS THE UPPER RIDGE AXIS FURTHER WEST AND THE GFS ENSEMBLE MEAN IS
IN BETWEEN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1144 AM MDT TUE AUG 6 2013
SCATTERED THUNDERSTORMS WILL DEVELOP ALONG TROUGH AXIS OVER NW
KS/SW NE THIS AFTERNOON AND INCREASE IN COVERAGE THROUGH THIS
EVENING AS THE ACTIVITY TRANSITIONS EAST. CURRENTLY COVERAGE IS
STILL TOO MUCH OF A QUESTION AT EITHER TERMINAL WITH BETTER
CHANCES FURTHER SOUTH AND EAST...SO I LIMITED MENTION TO VCTS.
LATE TONIGHT FOG/STRATUS IS EXPECTED TO REDEVELOP...WITH LOWER
CIGS/VIS AT BOTH TERMINALS BY SUNRISE. GUIDANCE CURRENTLY SUPPORTS
MVFR CONDITIONS...HOWEVER CONSIDERING THE MOIST NATURE OF THE
AIRMASS IF WINDS GO COMPLETELY CALM WE COULD SEE LOWER CONDITIONS
DEVELOP. FOR NOW I CHOSE TO STAY IN LINE WITH CURRENT
GUIDANCE...HOWEVER WE WILL NEED TO MONITOR THIS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BRB
AVIATION...DR
AREA FORECAST DISCUSSION
NWS JACKSON KY
1102 PM EDT WED AUG 7 2013
.UPDATE...
ISSUED AT 1102 PM EDT WED AUG 7 2013
RAIN IS STARTING TO PUSH INTO AREAS FROM MOUNT STERLING TO MOUNT
VERNON...BUT IS BEGINNING TO FALL APART. HRRR SEEMS TO HAVE A GOOD
HANDLE ON THIS TREND WITH THE CURRENT COMPLEX COLLAPSING WITH VERY
LITTLE FOR THE REST OF THE NIGHT. UPDATE HAS BEEN SENT.
UPDATE ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED ACROSS EASTERN
KENTUCKY. HAVE SEEN SOME NEW DEVELOPMENT OUT WEST OF LEXINGTON. THIS
ACTIVITY COULD MAKE IT INTO THE I-75 CORRIDOR OVER THE NEXT FEW
HOURS...BUT STILL SOME QUESTION IF THIS WILL MAKE IT INTO AREAS
FURTHER EAST. FOR NOW...GOING TO DOWNPLAY POPS FOR THE REST OF THE
NIGHT GIVEN THE CURRENT LACK OF ORGANIZED ACTIVITY. LATEST HRRR HAS
ALMOST NO SHOWER OR THUNDERSTORM ACTIVITY ACROSS THE AREA UNTIL 11Z.
THUS...THE DOWNWARD TREND IN POPS SEEMS REASONABLE. CAN`T IGNORE
THOSE HIGH PW`S NEAR 2 LATER TONIGHT...SO IT WON`T TAKE MUCH TO GET
SOME LOCALLY HEAVY RAIN...BUT STILL PLANNING TO PUSH ANY MENTION
UNTIL AFTER 12Z.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT WED AUG 7 2013
AFTER INITIAL ROUND OF SHOWERS AND A FEW THUNDERSTORMS THIS MORNING
CONVECTION HAS REMAINED LIMITED THIS AFTERNOON...WITH MOSTLY
SCATTERED SHOWERS...AND VERY LITTLE THUNDER. CLOUD COVER HAS INHIBITED
DESTABILIZATION AND WITH LOSS OF DAYTIME HEATING EXPECT CONVECTION TO
DIMINISH EVEN FURTHER THIS EVENING.
HOWEVER THIS WILL BE TEMPORARY...WITH A MID LEVEL SHORT WAVE TROUGH
MOVING EAST TONIGHT...AND A LOW LEVEL JET AT 8H IMPINGING ON EASTERN
KY AFTER 06Z. AT THE SAME TIME EXPECT A SURFACE WAVE OF LOW PRESSURE
TO TREK ALONG THE SURFACE FRONT TO THE NORTHWEST OF THE FORECAST AREA
THURSDAY MORNING. THERE IS GOOD MODEL AGREEMENT WITH INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS LATE TONIGHT INTO THE DAY ON
THURSDAY. DETERMINISTIC MODELS ALONG WITH THE SERF ARE POINTING
TOWARDS PRECIPITABLE WATER IN EXCESS OF 2 INCHES BY THURSDAY
MORNING. PRECIPITABLE WATER SHOULD APPROACH OR EXCEED THE 99TH
PERCENTILE. BASED ON THIS WILL ADD THE THREAT OF HEAVY RAIN TO THE
THURSDAY FORECAST AND THE HAZARDOUS WEATHER OUTLOOK. WITH ALL THIS IN
MIND WILL INCREASE RAIN PROBABILITIES LATE TONIGHT TO LIKELY IN THE
WEST...THEN LIKELY ACROSS THE ENTIRE AREA ON THURSDAY...BEFORE
DECREASING CHANCES AGAIN LATE IN THE DAY THURSDAY.
WITH THE FRONT STALLING SOMEWHERE IN THE OH VALLEY...THE TREAT OF
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THURSDAY NIGHT. THERE IS
LESS MODEL AGREEMENT ON THE TIMING OF THE NEXT SHORT WAVE WHICH WOULD
TRIGGER ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS BUT FOR FOR NOW
WILL CONTINUE THE PREVIOUS FORECAST IDEA OF INCREASING CHANCES AGAIN
LATE THURSDAY NIGHT.
HIGH DEWPOINTS WILL KEEP MINIMUM TEMPERATURES AROUND 70 TONIGHT AND
AGAIN THURSDAY NIGHT. WITH RAIN AND CLOUD IN THE FORECAST ON
THURSDAY...WILL GO WITH HIGHS IN THE LOWER 80S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 PM EDT WED AUG 7 2013
UNSETTLED WEATHER WILL CONTINUE INTO THE LONG TERM PERIOD. THE PERIOD
SHOULD BEGIN WITH A NEARLY STATIONARY BOUNDARY ACROSS THE OH VALLEY
EXTENDING SOUTHWEST INTO THE OH VALLEY FROM LOW PRESSURE OVER QUEBEC.
THERE MAY BE A WAVE OR SERIES OF SFC WAVES ALONG THE BOUNDARY TO OUR
WEST AT THAT POINT AS DISTURBANCES MOVING INTO THE REGION. AT THE
START OF THE PERIOD UPPER LEVEL RIDGING IS EXPECTED TO EXTEND ACROSS
THE SOUTHERN STATES AND NORTH INTO THE ROCKIES. AN UPPER LEVEL LOW
SHOULD BE ROTATING TO THE NORTH OF THE GREAT LAKES FROM ONTARIO.
THERE WILL PROBABLY BE SOME SHORTWAVES ROTATING TOWARD THE LOWER OH
VALLEY FROM THE PLAINS...BUT THERE ARE MODEL DIFFERENCES IN TIMING.
THE MODELS GRADUALLY SAG THE BOUNDARY SOUTH OF THE OH RIVER AND
EVENTUALLY INTO THE JKL CWA AND STRING IT OUT MORE WEST TO EAST AS THE
UPPER LOW WORKS TOWARD THE MARITIMES OVER THE WEEKEND. FROM EARLY TO
THE MIDDLE PART OF NEXT WEEK...THE TROUGH SHOULD DEEPEN AGAIN OVER
EASTERN CANADA AND THE NORTHEAST AS ANOTHER UPPER LEVEL LOW ROTATES
FROM THE HUDSON BAY REGION NORTH OF THE GREAT LAKES AND TOWARD THE
MARITIMES. THE MODEL CONSENSUS FROM EARLY TO THE MIDDLE PART OF NEXT
WEEK IS FOR MORE AMPLIFIED PATTERN WITH THE BOUNDARY PUSHING SOUTH OF
THE AREA...BUT WEST NORTHWEST UPPER FLOW SHOULD REMAIN. DISTURBANCES
IN THIS FLOW WILL STILL KEEP A THREAT OF CONVECTION IN THE PICTURE
FOR AT LEAST MON AND TUE...ESPECIALLY EACH AFTERNOON AND EVENING.
ENOUGH DRIER AIR MAY WORK INTO THE REGION LATE IN THE PERIOD IF THE
12Z ECMWF VERIFIES FOR DRY WEATHER ON WEDNESDAY OR TUESDAY AND
WEDNESDAY. HOWEVER...MODEL TO MODEL DIFFERENCES AND RUN TO RUN
DIFFERENCE REMAIN AND THE EXTENDED GRID LOAD OF ISOLATED TO
SCATTERED POPS WAS REASONABLE.
PW WILL REMAIN VERY HIGH ABOVE THE 90TH TO 95TH PERCENTILE RANGE INTO
EARLY IN THE PERIOD AHEAD OF THE BOUNDARY. THERE IS THE POTENTIAL FOR
ANY CONVECTION TO HAVE DEEP WARM CLOUD DEPTH AND THEY COULD PRODUCE
AT LEAST LOCALLY HEAVY RAIN. TIMING AND STRENGTH OF PASSING UPPER
LEVEL SHORTWAVES WILL BE A KEY INGREDIENT AND CONFIDENCE IN THIS IS
NOT HIGH AT THIS POINT. HOWEVER...WE WILL HIGHLIGHT THIS IN THE HWO.
TEMPERATURES THROUGH THE PERIOD SHOULD REMAIN NEAR IF NOT A BIT BELOW
NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS EARLY IN THE PERIOD A
BIT ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWERS HAVE DIMINISHED ACROSS EASTERN KENTUCKY AND TAFS WILL ALL
START OFF VFR. WITH LOTS OF LOW LEVEL MOISTURE PRESENT...SOME STRATUS
SHOULD DEVELOP OVERNIGHT...MUCH LIKE LAST NIGHT. IN ADDITION SOME
RAIN COULD START TO INVADE THE AREA TOWARDS DAYBREAK. WITH CLOUD
COVER FAIRLY HIGH TONIGHT...NO FOG EXPECTED AT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SBH
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
746 PM EDT WED AUG 7 2013
.UPDATE...
ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED ACROSS EASTERN
KENTUCKY. HAVE SEEN SOME NEW DEVELOPMENT OUT WEST OF LEXINGTON. THIS
ACTIVITY COULD MAKE IT INTO THE I-75 CORRIDOR OVER THE NEXT FEW
HOURS...BUT STILL SOME QUESTION IF THIS WILL MAKE IT INTO AREAS
FURTHER EAST. FOR NOW...GOING TO DOWNPLAY POPS FOR THE REST OF THE
NIGHT GIVEN THE CURRENT LACK OF ORGANIZED ACTIVITY. LATEST HRRR HAS
ALMOST NO SHOWER OR THUNDERSTORM ACTIVITY ACROSS THE AREA UNTIL 11Z.
THUS...THE DOWNWARD TREND IN POPS SEEMS REASONABLE. CAN`T IGNORE
THOSE HIGH PW`S NEAR 2 LATER TONIGHT...SO IT WON`T TAKE MUCH TO GET
SOME LOCALLY HEAVY RAIN...BUT STILL PLANNING TO PUSH ANY MENTION
UNTIL AFTER 12Z.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT WED AUG 7 2013
AFTER INITIAL ROUND OF SHOWERS AND A FEW THUNDERSTORMS THIS MORNING
CONVECTION HAS REMAINED LIMITED THIS AFTERNOON...WITH MOSTLY
SCATTERED SHOWERS...AND VERY LITTLE THUNDER. CLOUD COVER HAS INHIBITED
DESTABILIZATION AND WITH LOSS OF DAYTIME HEATING EXPECT CONVECTION TO
DIMINISH EVEN FURTHER THIS EVENING.
HOWEVER THIS WILL BE TEMPORARY...WITH A MID LEVEL SHORT WAVE TROUGH
MOVING EAST TONIGHT...AND A LOW LEVEL JET AT 8H IMPINGING ON EASTERN
KY AFTER 06Z. AT THE SAME TIME EXPECT A SURFACE WAVE OF LOW PRESSURE
TO TREK ALONG THE SURFACE FRONT TO THE NORTHWEST OF THE FORECAST AREA
THURSDAY MORNING. THERE IS GOOD MODEL AGREEMENT WITH INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS LATE TONIGHT INTO THE DAY ON
THURSDAY. DETERMINISTIC MODELS ALONG WITH THE SERF ARE POINTING
TOWARDS PRECIPITABLE WATER IN EXCESS OF 2 INCHES BY THURSDAY
MORNING. PRECIPITABLE WATER SHOULD APPROACH OR EXCEED THE 99TH
PERCENTILE. BASED ON THIS WILL ADD THE THREAT OF HEAVY RAIN TO THE
THURSDAY FORECAST AND THE HAZARDOUS WEATHER OUTLOOK. WITH ALL THIS IN
MIND WILL INCREASE RAIN PROBABILITIES LATE TONIGHT TO LIKELY IN THE
WEST...THEN LIKELY ACROSS THE ENTIRE AREA ON THURSDAY...BEFORE
DECREASING CHANCES AGAIN LATE IN THE DAY THURSDAY.
WITH THE FRONT STALLING SOMEWHERE IN THE OH VALLEY...THE TREAT OF
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THURSDAY NIGHT. THERE IS
LESS MODEL AGREEMENT ON THE TIMING OF THE NEXT SHORT WAVE WHICH WOULD
TRIGGER ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS BUT FOR FOR NOW
WILL CONTINUE THE PREVIOUS FORECAST IDEA OF INCREASING CHANCES AGAIN
LATE THURSDAY NIGHT.
HIGH DEWPOINTS WILL KEEP MINIMUM TEMPERATURES AROUND 70 TONIGHT AND
AGAIN THURSDAY NIGHT. WITH RAIN AND CLOUD IN THE FORECAST ON
THURSDAY...WILL GO WITH HIGHS IN THE LOWER 80S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 PM EDT WED AUG 7 2013
UNSETTLED WEATHER WILL CONTINUE INTO THE LONG TERM PERIOD. THE PERIOD
SHOULD BEGIN WITH A NEARLY STATIONARY BOUNDARY ACROSS THE OH VALLEY
EXTENDING SOUTHWEST INTO THE OH VALLEY FROM LOW PRESSURE OVER QUEBEC.
THERE MAY BE A WAVE OR SERIES OF SFC WAVES ALONG THE BOUNDARY TO OUR
WEST AT THAT POINT AS DISTURBANCES MOVING INTO THE REGION. AT THE
START OF THE PERIOD UPPER LEVEL RIDGING IS EXPECTED TO EXTEND ACROSS
THE SOUTHERN STATES AND NORTH INTO THE ROCKIES. AN UPPER LEVEL LOW
SHOULD BE ROTATING TO THE NORTH OF THE GREAT LAKES FROM ONTARIO.
THERE WILL PROBABLY BE SOME SHORTWAVES ROTATING TOWARD THE LOWER OH
VALLEY FROM THE PLAINS...BUT THERE ARE MODEL DIFFERENCES IN TIMING.
THE MODELS GRADUALLY SAG THE BOUNDARY SOUTH OF THE OH RIVER AND
EVENTUALLY INTO THE JKL CWA AND STRING IT OUT MORE WEST TO EAST AS THE
UPPER LOW WORKS TOWARD THE MARITIMES OVER THE WEEKEND. FROM EARLY TO
THE MIDDLE PART OF NEXT WEEK...THE TROUGH SHOULD DEEPEN AGAIN OVER
EASTERN CANADA AND THE NORTHEAST AS ANOTHER UPPER LEVEL LOW ROTATES
FROM THE HUDSON BAY REGION NORTH OF THE GREAT LAKES AND TOWARD THE
MARITIMES. THE MODEL CONSENSUS FROM EARLY TO THE MIDDLE PART OF NEXT
WEEK IS FOR MORE AMPLIFIED PATTERN WITH THE BOUNDARY PUSHING SOUTH OF
THE AREA...BUT WEST NORTHWEST UPPER FLOW SHOULD REMAIN. DISTURBANCES
IN THIS FLOW WILL STILL KEEP A THREAT OF CONVECTION IN THE PICTURE
FOR AT LEAST MON AND TUE...ESPECIALLY EACH AFTERNOON AND EVENING.
ENOUGH DRIER AIR MAY WORK INTO THE REGION LATE IN THE PERIOD IF THE
12Z ECMWF VERIFIES FOR DRY WEATHER ON WEDNESDAY OR TUESDAY AND
WEDNESDAY. HOWEVER...MODEL TO MODEL DIFFERENCES AND RUN TO RUN
DIFFERENCE REMAIN AND THE EXTENDED GRID LOAD OF ISOLATED TO
SCATTERED POPS WAS REASONABLE.
PW WILL REMAIN VERY HIGH ABOVE THE 90TH TO 95TH PERCENTILE RANGE INTO
EARLY IN THE PERIOD AHEAD OF THE BOUNDARY. THERE IS THE POTENTIAL FOR
ANY CONVECTION TO HAVE DEEP WARM CLOUD DEPTH AND THEY COULD PRODUCE
AT LEAST LOCALLY HEAVY RAIN. TIMING AND STRENGTH OF PASSING UPPER
LEVEL SHORTWAVES WILL BE A KEY INGREDIENT AND CONFIDENCE IN THIS IS
NOT HIGH AT THIS POINT. HOWEVER...WE WILL HIGHLIGHT THIS IN THE HWO.
TEMPERATURES THROUGH THE PERIOD SHOULD REMAIN NEAR IF NOT A BIT BELOW
NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS EARLY IN THE PERIOD A
BIT ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWERS HAVE DIMINISHED ACROSS EASTERN KENTUCKY AND TAFS WILL ALL
START OFF VFR. WITH LOTS OF LOW LEVEL MOISTURE PRESENT...SOME STRATUS
SHOULD DEVELOP OVERNIGHT...MUCH LIKE LAST NIGHT. IN ADDITION SOME
RAIN COULD START TO INVADE THE AREA TOWARDS DAYBREAK. WITH CLOUD
COVER FAIRLY HIGH TONIGHT...NO FOG EXPECTED AT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...SBH
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1213 PM EDT TUE AUG 6 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE COULD TRIGGER A SHOWER OR
THUNDERSTORM THIS AFTERNOON. OTHERWISE, HIGH PRESSURE WILL BUILD
ACROSS THE AREA TODAY AND MOVE EAST OF THE REGION ON WEDNESDAY AS
ANOTHER FRONT APPROACHES FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
NOON UPDATE...CUMULUS HAVE FORMED ACROSS MANY AREAS. MODIFIED
CLOUDS COVER TO GO PARTLY CLOUDY IN NORTH CENTRAL AND WESTERN
AREAS WITH CUMULUS CLOUDS. REST OF THE FORECAST REMAINS ON TRACK.
PREVIOUS DISCUSSION...
DRIER AND MILDER TODAY.
A WEAK RIDGE OF HIGH PRES AT THE SFC IS SET TO MOVE OVER THE
REGION TODAY INTO TONIGHT. DRIER WEATHER W/MORE SUNSHINE WILL BE
SEEN TODAY W/TEMPERATURES RESPONDING INTO THE MID AND UPPER 70S.
THE CAVEAT TO THIS HOWEVER WILL BE A WEAK S/WV IN THE UPPER LEVELS
THAT WILL MOVE ACROSS THE STATE THIS AFTERNOON. THIS FEATURE IS
PICKED UP WELL BY THE 00Z NAM AND CANADIAN GEM PER 06Z ANALYSIS
OVER ONTARIO. IR SATL IMAGERY SHOWED SOME MID/HIGH CLOUDS ASSOCIATED
W/THIS FEATURE MOVING INTO WESTERN AND NORTHERN NYS. GFS/NAM
SOUNDINGS AS WELL AS THE GEM SHOW SOME MOISTURE AT THE 850MB LEVEL
W/THE MAJORITY OF THE RH ABOVE 700MBS. LATEST TRAJECTORIES BRING
SOME CLOUDINESS`S ACROSS PORTIONS OF WESTERN AND NORTHERN AREAS
TODAY. SOUNDINGS DO INDICATE SOME INSTABILITY AS LIS DROP TO -1 TO
-3 AND SBCAPES HIT CLOSE TO 500 JOULES. THERE IS SOME WEAK SHEAR
AT 0-6KM OF 15 KTS OR SO. 850-700MB LAPSE RATES FROM THE NAM ARE
CLOSE TO 7.0 C/KM AND SOME LLVL CONVERGENCE NOTED. ALL THIS COULD
BE ENOUGH TO TRIGGER SOME ISOLD SHOWERS OR PERHAPS A TSTM MAINLY
FOR THE WESTERN AND NWRN AREAS. THE NAM AND GFS HINT AT THIS TO
SET UP. EVEN THE 06Z HRRR SHOWS WIDELY SCATTERED TO ISOLD PRECIP.
THEREFORE, DECIDED TO ADD THE MENTION OF A SHOWER OR POSSIBLE
TSTM INTO LATE AFTERNOON(20%).
ACTIVITY WILL WIND DOWN IN THE EVENING AS THE S/WV MOVES TO THE E
AND LOSS OF HEATING. HIGH PRES IN THE GULF OF MAINE WILL RIDGE
OVER THE REGION TONIGHT. CLEARING SKIES AND COOLER TEMPERATURES
WILL ALLOW FOR SOME FOG TO DEVELOP. OVERNIGHT LOWS ARE EXPECTED
TO DROP BACK INTO THE UPPER 40S ACROSS THE N AND NW WHILE LOWER
50S SHOULD DO IT FOR CENTRAL AND DOWNEAST AREAS.SATURATED GROUND
AND DAYTIME HEATING WILL AID IN THE FOG DEVELOPMENT. ATTM, WENT
W/PATCHY FOG. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION DURING WEDNESDAY. AFTER A
MAINLY SUNNY START TO THE DAY EXPECT INCREASING HIGH CLOUDS IN
ADVANCE OF THE NEXT TROF APPROACHING FROM THE WEST. THE MAIN
CHANGE TO THE WEDNESDAY FORECAST WAS TO DELAY THE ONSET OF ANY
SHOWERS GETTING INTO THE WESTERN AREAS UNTIL WEDNESDAY EVENING.
HIGH TEMPERATURES ON WEDNESDAY WILL BE CLOSE TO NORMAL FOR THIS
TIME OF YEAR WITH MID 70S TO NEAR 80 DEGREES ACROSS THE REGION.
CLOUDS WILL CONTINUE TO INCREASE WEDNESDAY NIGHT WITH SHOWERS
DEVELOPING FROM WEST TO EAST AFTER MIDNIGHT IN ADVANCE OF AN
APPROACHING WARM FRONT. LOWS WEDNESDAY NIGHT ARE EXPECTED TO RANGE
FROM THE MID TO UPPER 50S ACROSS THE REGION.
SHOWERS WILL CONTINUE TO BE LIKELY ON THURSDAY IN ADVANCE OF THE
APPROACHING COLD FRONT. HIGH TEMPERATURES ON THURSDAY WILL BE A BIT
BELOW NORMAL FOR THIS TIME OF YEAR DUE TO THE COMBINATION OF CLOUDS
AND SHOWERS. HIGHS WILL RANGE FROM THE UPPER 60S TO NEAR 70 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE WEAK SURFACE COLD FRONT WILL SLOWLY CROSS THE REGION THURSDAY
NIGHT WITH SHOWERS TAPERING OFF FROM WEST TO EAST AFTER MIDNIGHT.
THE WEAKENING FRONT WILL STALL NEAR OR ALONG THE COAST LATER
THURSDAY NIGHT AND FRIDAY. LATEST MODEL GUIDANCE SUGGESTS FRIDAY
MAY BE A MAINLY DRY ALTHOUGH MOSTLY CLOUDY DAY.
A VIGOROUS 500MB LOW WILL MOVE EAST INTO QUEBEC LATER FRIDAY AND
SATURDAY. MODELS DIVERGE ON THE OVERALL SENSIBLE WEATHER FOR LATER
FRIDAY NIGHT AND INTO SATURDAY. THE 00Z OP RUN OF THE GFS DEVELOPS A
COMPACT SURFACE LOW ACROSS NYS FRIDAY NIGHT AND THEN TRACKS IT
ACROSS NEW ENGLAND AND ACROSS DOWNEAST MAINE FRIDAY NIGHT. 00Z EC IS
FURTHER SOUTH AND WEAKER WITH THE LOW KEEPING THE REGION MAINLY DRY.
FOR NOW HAVE KEPT CONTINUITY WITH GOING FORECAST AND WENT WITH LOW
CHANCE POPS FRIDAY NIGHT AND INTO SATURDAY.
COOLER AND DRIER AIR WILL WILL FOLLOW FOR LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH TEMPERATURES AVERAGING BELOW SEASONAL FOR THIS
TIME OF YEAR.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR THROUGH TONIGHT FOR ALL TERMINALS. THERE IS
POTENTIAL FOR SOME FOG TO DEVELOP LATE TONIGHT MAINLY ACROSS THE
NORTHERN TERMINALS DUE TO THE WET GROUND AND CLEARING. CONDITIONS
COULD BRIEFLY DROP TO MVFR OR PERHAPS IFR BY EARLY WEDNESDAY MORNING.
SHORT TERM: VFR WEDNESDAY. MVFR WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN SHOWERS. VFR FRIDAY AND SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. WINDS WILL TURN TO THE SW LATER
TODAY AND AVERAGE 10 KT OR SO. WAVE HEIGHTS WILL STAY AT 2-3 FT
MAINLY AWAY FROM THE INTRA-COASTAL ZONE.
SHORT TERM: WINDS/SEAS SHOULD REMAIN BELOW SCA LEVELS FOR THIS
TERM.
&&
.MARINE...
NEAR TERM:
SHORT TERM:
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
921 AM EDT TUE AUG 6 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE COULD TRIGGER A SHOWER OR
THUNDERSTORM THIS AFTERNOON. OTHERWISE, HIGH PRESSURE WILL BUILD
ACROSS THE AREA TODAY AND MOVE EAST OF THE REGION ON WEDNESDAY AS
ANOTHER FRONT APPROACHES FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
9:00 AM UPDATE...BROUGHT TEMPS UP A DEGREE AND MADE SKIES MOSTLY
CLEAR ACROSS THE AREA WITH PLENTY OF SUNSHINE AROUND. EXPECT A FEW
CUMULUS TO DEVELOP THROUGH MIDDAY. AN ISOLATED THUNDERSHOWER IS
POSSIBLE IN SOME SPOTS.
PREVIOUS DISCUSSION...
DRIER AND MILDER TODAY.
A WEAK RIDGE OF HIGH PRES AT THE SFC IS SET TO MOVE OVER THE
REGION TODAY INTO TONIGHT. DRIER WEATHER W/MORE SUNSHINE WILL BE
SEEN TODAY W/TEMPERATURES RESPONDING INTO THE MID AND UPPER 70S.
THE CAVEAT TO THIS HOWEVER WILL BE A WEAK S/WV IN THE UPPER LEVELS
THAT WILL MOVE ACROSS THE STATE THIS AFTERNOON. THIS FEATURE IS
PICKED UP WELL BY THE 00Z NAM AND CANADIAN GEM PER 06Z ANALYSIS
OVER ONTARIO. IR SATL IMAGERY SHOWED SOME MID/HIGH CLOUDS ASSOCIATED
W/THIS FEATURE MOVING INTO WESTERN AND NORTHERN NYS. GFS/NAM
SOUNDINGS AS WELL AS THE GEM SHOW SOME MOISTURE AT THE 850MB LEVEL
W/THE MAJORITY OF THE RH ABOVE 700MBS. LATEST TRAJECTORIES BRING
SOME CLOUDINESS`S ACROSS PORTIONS OF WESTERN AND NORTHERN AREAS
TODAY. SOUNDINGS DO INDICATE SOME INSTABILITY AS LIS DROP TO -1 TO
-3 AND SBCAPES HIT CLOSE TO 500 JOULES. THERE IS SOME WEAK SHEAR
AT 0-6KM OF 15 KTS OR SO. 850-700MB LAPSE RATES FROM THE NAM ARE
CLOSE TO 7.0 C/KM AND SOME LLVL CONVERGENCE NOTED. ALL THIS COULD
BE ENOUGH TO TRIGGER SOME ISOLD SHOWERS OR PERHAPS A TSTM MAINLY
FOR THE WESTERN AND NWRN AREAS. THE NAM AND GFS HINT AT THIS TO
SET UP. EVEN THE 06Z HRRR SHOWS WIDELY SCATTERED TO ISOLD PRECIP.
THEREFORE, DECIDED TO ADD THE MENTION OF A SHOWER OR POSSIBLE
TSTM INTO LATE AFTERNOON(20%).
ACTIVITY WILL WIND DOWN IN THE EVENING AS THE S/WV MOVES TO THE E
AND LOSS OF HEATING. HIGH PRES IN THE GULF OF MAINE WILL RIDGE
OVER THE REGION TONIGHT. CLEARING SKIES AND COOLER TEMPERATURES
WILL ALLOW FOR SOME FOG TO DEVELOP. OVERNIGHT LOWS ARE EXPECTED
TO DROP BACK INTO THE UPPER 40S ACROSS THE N AND NW WHILE LOWER
50S SHOULD DO IT FOR CENTRAL AND DOWNEAST AREAS.SATURATED GROUND
AND DAYTIME HEATING WILL AID IN THE FOG DEVELOPMENT. ATTM, WENT
W/PATCHY FOG. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION DURING WEDNESDAY. AFTER A
MAINLY SUNNY START TO THE DAY EXPECT INCREASING HIGH CLOUDS IN
ADVANCE OF THE NEXT TROF APPROACHING FROM THE WEST. THE MAIN
CHANGE TO THE WEDNESDAY FORECAST WAS TO DELAY THE ONSET OF ANY
SHOWERS GETTING INTO THE WESTERN AREAS UNTIL WEDNESDAY EVENING.
HIGH TEMPERATURES ON WEDNESDAY WILL BE CLOSE TO NORMAL FOR THIS
TIME OF YEAR WITH MID 70S TO NEAR 80 DEGREES ACROSS THE REGION.
CLOUDS WILL CONTINUE TO INCREASE WEDNESDAY NIGHT WITH SHOWERS
DEVELOPING FROM WEST TO EAST AFTER MIDNIGHT IN ADVANCE OF AN
APPROACHING WARM FRONT. LOWS WEDNESDAY NIGHT ARE EXPECTED TO RANGE
FROM THE MID TO UPPER 50S ACROSS THE REGION.
SHOWERS WILL CONTINUE TO BE LIKELY ON THURSDAY IN ADVANCE OF THE
APPROACHING COLD FRONT. HIGH TEMPERATURES ON THURSDAY WILL BE A BIT
BELOW NORMAL FOR THIS TIME OF YEAR DUE TO THE COMBINATION OF CLOUDS
AND SHOWERS. HIGHS WILL RANGE FROM THE UPPER 60S TO NEAR 70 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE WEAK SURFACE COLD FRONT WILL SLOWLY CROSS THE REGION THURSDAY
NIGHT WITH SHOWERS TAPERING OFF FROM WEST TO EAST AFTER MIDNIGHT.
THE WEAKENING FRONT WILL STALL NEAR OR ALONG THE COAST LATER
THURSDAY NIGHT AND FRIDAY. LATEST MODEL GUIDANCE SUGGESTS FRIDAY
MAY BE A MAINLY DRY ALTHOUGH MOSTLY CLOUDY DAY.
A VIGOROUS 500MB LOW WILL MOVE EAST INTO QUEBEC LATER FRIDAY AND
SATURDAY. MODELS DIVERGE ON THE OVERALL SENSIBLE WEATHER FOR LATER
FRIDAY NIGHT AND INTO SATURDAY. THE 00Z OP RUN OF THE GFS DEVELOPS A
COMPACT SURFACE LOW ACROSS NYS FRIDAY NIGHT AND THEN TRACKS IT
ACROSS NEW ENGLAND AND ACROSS DOWNEAST MAINE FRIDAY NIGHT. 00Z EC IS
FURTHER SOUTH AND WEAKER WITH THE LOW KEEPING THE REGION MAINLY DRY.
FOR NOW HAVE KEPT CONTINUITY WITH GOING FORECAST AND WENT WITH LOW
CHANCE POPS FRIDAY NIGHT AND INTO SATURDAY.
COOLER AND DRIER AIR WILL WILL FOLLOW FOR LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH TEMPERATURES AVERAGING BELOW SEASONAL FOR THIS
TIME OF YEAR.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR THROUGH TONIGHT FOR ALL TERMINALS. THERE IS
POTENTIAL FOR SOME FOG TO DEVELOP LATE TONIGHT MAINLY ACROSS THE
NORTHERN TERMINALS DUE TO THE WET GROUND AND CLEARING. CONDITIONS
COULD BRIEFLY DROP TO MVFR OR PERHAPS IFR BY EARLY WEDNESDAY MORNING.
SHORT TERM: VFR WEDNESDAY. MVFR WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN SHOWERS. VFR FRIDAY AND SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. WINDS WILL TURN TO THE SW LATER
TODAY AND AVERAGE 10 KT OR SO. WAVE HEIGHTS WILL STAY AT 2-3 FT
MAINLY AWAY FROM THE INTRA-COASTAL ZONE.
SHORT TERM: WINDS/SEAS SHOULD REMAIN BELOW SCA LEVELS FOR THIS
TERM.
&&
.MARINE...
NEAR TERM:
SHORT TERM:
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
643 AM EDT TUE AUG 6 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE COULD TRIGGER A SHOWER OR
THUNDERSTORM THIS AFTERNOON. OTHERWISE, HIGH PRESSURE WILL BUILD
ACROSS THE AREA TODAY AND MOVE EAST OF THE REGION ON WEDNESDAY AS
ANOTHER FRONT APPROACHES FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM UPDATE: MODIFIED THE SKY AND TEMPERATURES TO BRING THEM TO
THE CURRENT CONDITIONS SHOWING MAINLY CLEAR AND COOL CONDITIONS.
SOME AREAS BACK ACROSS WEST AND NORTHWEST MAINE DROPPED BACK INTO
THE MID AND UPPER 30S W/LOWER 40S AT ALLAGASH AND DICKEY.
ELSEWHERE, READINGS WERE IN THE UPPER 40S AND LOWER 50S. EXPECTING
THOSE TEMPERATURES TO REBOUND AFTER 8 AM W/THE AID OF THE SUN.
PREVIOUS DISCUSSION...
DRIER AND MILDER TODAY.
A WEAK RIDGE OF HIGH PRES AT THE SFC IS SET TO MOVE OVER THE
REGION TODAY INTO TONIGHT. DRIER WEATHER W/MORE SUNSHINE WILL BE
SEEN TODAY W/TEMPERATURES RESPONDING INTO THE MID AND UPPER 70S.
THE CAVEAT TO THIS HOWEVER WILL BE A WEAK S/WV IN THE UPPER LEVELS
THAT WILL MOVE ACROSS THE STATE THIS AFTERNOON. THIS FEATURE IS
PICKED UP WELL BY THE 00Z NAM AND CANADIAN GEM PER 06Z ANALYSIS
OVER ONTARIO. IR SATL IMAGERY SHOWED SOME MID/HIGH CLOUDS ASSOCIATED
W/THIS FEATURE MOVING INTO WESTERN AND NORTHERN NYS. GFS/NAM
SOUNDINGS AS WELL AS THE GEM SHOW SOME MOISTURE AT THE 850MB LEVEL
W/THE MAJORITY OF THE RH ABOVE 700MBS. LATEST TRAJECTORIES BRING
SOME CLOUDINESS`S ACROSS PORTIONS OF WESTERN AND NORTHERN AREAS
TODAY. SOUNDINGS DO INDICATE SOME INSTABILITY AS LIS DROP TO -1 TO
-3 AND SBCAPES HIT CLOSE TO 500 JOULES. THERE IS SOME WEAK SHEAR
AT 0-6KM OF 15 KTS OR SO. 850-700MB LAPSE RATES FROM THE NAM ARE
CLOSE TO 7.0 C/KM AND SOME LLVL CONVERGENCE NOTED. ALL THIS COULD
BE ENOUGH TO TRIGGER SOME ISOLD SHOWERS OR PERHAPS A TSTM MAINLY
FOR THE WESTERN AND NWRN AREAS. THE NAM AND GFS HINT AT THIS TO
SET UP. EVEN THE 06Z HRRR SHOWS WIDELY SCATTERED TO ISOLD PRECIP.
THEREFORE, DECIDED TO ADD THE MENTION OF A SHOWER OR POSSIBLE
TSTM INTO LATE AFTERNOON(20%).
ACTIVITY WILL WIND DOWN IN THE EVENING AS THE S/WV MOVES TO THE E
AND LOSS OF HEATING. HIGH PRES IN THE GULF OF MAINE WILL RIDGE
OVER THE REGION TONIGHT. CLEARING SKIES AND COOLER TEMPERATURES
WILL ALLOW FOR SOME FOG TO DEVELOP. OVERNIGHT LOWS ARE EXPECTED
TO DROP BACK INTO THE UPPER 40S ACROSS THE N AND NW WHILE LOWER
50S SHOULD DO IT FOR CENTRAL AND DOWNEAST AREAS.SATURATED GROUND
AND DAYTIME HEATING WILL AID IN THE FOG DEVELOPMENT. ATTM, WENT
W/PATCHY FOG. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION DURING WEDNESDAY. AFTER A
MAINLY SUNNY START TO THE DAY EXPECT INCREASING HIGH CLOUDS IN
ADVANCE OF THE NEXT TROF APPROACHING FROM THE WEST. THE MAIN
CHANGE TO THE WEDNESDAY FORECAST WAS TO DELAY THE ONSET OF ANY
SHOWERS GETTING INTO THE WESTERN AREAS UNTIL WEDNESDAY EVENING.
HIGH TEMPERATURES ON WEDNESDAY WILL BE CLOSE TO NORMAL FOR THIS
TIME OF YEAR WITH MID 70S TO NEAR 80 DEGREES ACROSS THE REGION.
CLOUDS WILL CONTINUE TO INCREASE WEDNESDAY NIGHT WITH SHOWERS
DEVELOPING FROM WEST TO EAST AFTER MIDNIGHT IN ADVANCE OF AN
APPROACHING WARM FRONT. LOWS WEDNESDAY NIGHT ARE EXPECTED TO RANGE
FROM THE MID TO UPPER 50S ACROSS THE REGION.
SHOWERS WILL CONTINUE TO BE LIKELY ON THURSDAY IN ADVANCE OF THE
APPROACHING COLD FRONT. HIGH TEMPERATURES ON THURSDAY WILL BE A BIT
BELOW NORMAL FOR THIS TIME OF YEAR DUE TO THE COMBINATION OF CLOUDS
AND SHOWERS. HIGHS WILL RANGE FROM THE UPPER 60S TO NEAR 70 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE WEAK SURFACE COLD FRONT WILL SLOWLY CROSS THE REGION THURSDAY
NIGHT WITH SHOWERS TAPERING OFF FROM WEST TO EAST AFTER MIDNIGHT.
THE WEAKENING FRONT WILL STALL NEAR OR ALONG THE COAST LATER
THURSDAY NIGHT AND FRIDAY. LATEST MODEL GUIDANCE SUGGESTS FRIDAY
MAY BE A MAINLY DRY ALTHOUGH MOSTLY CLOUDY DAY.
A VIGOROUS 500MB LOW WILL MOVE EAST INTO QUEBEC LATER FRIDAY AND
SATURDAY. MODELS DIVERGE ON THE OVERALL SENSIBLE WEATHER FOR LATER
FRIDAY NIGHT AND INTO SATURDAY. THE 00Z OP RUN OF THE GFS DEVELOPS A
COMPACT SURFACE LOW ACROSS NYS FRIDAY NIGHT AND THEN TRACKS IT
ACROSS NEW ENGLAND AND ACROSS DOWNEAST MAINE FRIDAY NIGHT. 00Z EC IS
FURTHER SOUTH AND WEAKER WITH THE LOW KEEPING THE REGION MAINLY DRY.
FOR NOW HAVE KEPT CONTINUITY WITH GOING FORECAST AND WENT WITH LOW
CHANCE POPS FRIDAY NIGHT AND INTO SATURDAY.
COOLER AND DRIER AIR WILL WILL FOLLOW FOR LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH TEMPERATURES AVERAGING BELOW SEASONAL FOR THIS
TIME OF YEAR.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR THROUGH TONIGHT FOR ALL TERMINALS. THERE IS
POTENTIAL FOR SOME FOG TO DEVELOP LATE TONIGHT MAINLY ACROSS THE
NORTHERN TERMINALS DUE TO THE WET GROUND AND CLEARING. CONDITIONS
COULD BRIEFLY DROP TO MVFR OR PERHAPS IFR BY EARLY WEDNESDAY MORNING.
SHORT TERM: VFR WEDNESDAY. MVFR WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN SHOWERS. VFR FRIDAY AND SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. WINDS WILL TURN TO THE SW LATER
TODAY AND AVERAGE 10 KT OR SO. WAVE HEIGHTS WILL STAY AT 2-3 FT
MAINLY AWAY FROM THE INTRA-COASTAL ZONE.
SHORT TERM: WINDS/SEAS SHOULD REMAIN BELOW SCA LEVELS FOR THIS
TERM.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
443 AM EDT TUE AUG 6 2013
.SYNOPSIS...
A WEAK UPPER LEVEL DISTURBANCE COULD TRIGGER A SHOWER OR
THUNDERSTORM THIS AFTERNOON. OTHERWISE, HIGH PRESSURE WILL BUILD
ACROSS THE AREA TODAY AND MOVE EAST OF THE REGION ON WEDNESDAY AS
ANOTHER FRONT APPROACHES FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
DRIER AND MILDER TODAY.
A WEAK RIDGE OF HIGH PRES AT THE SFC IS SET TO MOVE OVER THE
REGION TODAY INTO TONIGHT. DRIER WEATHER W/MORE SUNSHINE WILL BE
SEEN TODAY W/TEMPERATURES RESPONDING INTO THE MID AND UPPER 70S.
THE CAVEAT TO THIS HOWEVER WILL BE A WEAK S/WV IN THE UPPER LEVELS
THAT WILL MOVE ACROSS THE STATE THIS AFTERNOON. THIS FEATURE IS
PICKED UP WELL BY THE 00Z NAM AND CANADIAN GEM PER 06Z ANALYSIS
OVER ONTARIO. IR SATL IMAGERY SHOWED SOME MID/HIGH CLOUDS ASSOCIATED
W/THIS FEATURE MOVING INTO WESTERN AND NORTHERN NYS. GFS/NAM
SOUNDINGS AS WELL AS THE GEM SHOW SOME MOISTURE AT THE 850MB LEVEL
W/THE MAJORITY OF THE RH ABOVE 700MBS. LATEST TRAJECTORIES BRING
SOME CLOUDINESS`S ACROSS PORTIONS OF WESTERN AND NORTHERN AREAS
TODAY. SOUNDINGS DO INDICATE SOME INSTABILITY AS LIS DROP TO -1 TO
-3 AND SBCAPES HIT CLOSE TO 500 JOULES. THERE IS SOME WEAK SHEAR
AT 0-6KM OF 15 KTS OR SO. 850-700MB LAPSE RATES FROM THE NAM ARE
CLOSE TO 7.0 C/KM AND SOME LLVL CONVERGENCE NOTED. ALL THIS COULD
BE ENOUGH TO TRIGGER SOME ISOLD SHOWERS OR PERHAPS A TSTM MAINLY
FOR THE WESTERN AND NWRN AREAS. THE NAM AND GFS HINT AT THIS TO
SET UP. EVEN THE 06Z HRRR SHOWS WIDELY SCATTERED TO ISOLD PRECIP.
THEREFORE, DECIDED TO ADD THE MENTION OF A SHOWER OR POSSIBLE
TSTM INTO LATE AFTERNOON(20%).
ACTIVITY WILL WIND DOWN IN THE EVENING AS THE S/WV MOVES TO THE E
AND LOSS OF HEATING. HIGH PRES IN THE GULF OF MAINE WILL RIDGE
OVER THE REGION TONIGHT. CLEARING SKIES AND COOLER TEMPERATURES
WILL ALLOW FOR SOME FOG TO DEVELOP. OVERNIGHT LOWS ARE EXPECTED
TO DROP BACK INTO THE UPPER 40S ACROSS THE N AND NW WHILE LOWER
50S SHOULD DO IT FOR CENTRAL AND DOWNEAST AREAS.SATURATED GROUND
AND DAYTIME HEATING WILL AID IN THE FOG DEVELOPMENT. ATTM, WENT
W/PATCHY FOG. DAYCREW CAN ASSESS THIS FURTHER TODAY.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL MOVE EAST OF THE REGION DURING WEDNESDAY. AFTER A
MAINLY SUNNY START TO THE DAY EXPECT INCREASING HIGH CLOUDS IN
ADVANCE OF THE NEXT TROF APPROACHING FROM THE WEST. THE MAIN
CHANGE TO THE WEDNESDAY FORECAST WAS TO DELAY THE ONSET OF ANY
SHOWERS GETTING INTO THE WESTERN AREAS UNTIL WEDNESDAY EVENING.
HIGH TEMPERATURES ON WEDNESDAY WILL BE CLOSE TO NORMAL FOR THIS
TIME OF YEAR WITH MID 70S TO NEAR 80 DEGREES ACROSS THE REGION.
CLOUDS WILL CONTINUE TO INCREASE WEDNESDAY NIGHT WITH SHOWERS
DEVELOPING FROM WEST TO EAST AFTER MIDNIGHT IN ADVANCE OF AN
APPROACHING WARM FRONT. LOWS WEDNESDAY NIGHT ARE EXPECTED TO RANGE
FROM THE MID TO UPPER 50S ACROSS THE REGION.
SHOWERS WILL CONTINUE TO BE LIKELY ON THURSDAY IN ADVANCE OF THE
APPROACHING COLD FRONT. HIGH TEMPERATURES ON THURSDAY WILL BE A BIT
BELOW NORMAL FOR THIS TIME OF YEAR DUE TO THE COMBINATION OF CLOUDS
AND SHOWERS. HIGHS WILL RANGE FROM THE UPPER 60S TO NEAR 70 DEGREES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
THE WEAK SURFACE COLD FRONT WILL SLOWLY CROSS THE REGION THURSDAY
NIGHT WITH SHOWERS TAPERING OFF FROM WEST TO EAST AFTER MIDNIGHT.
THE WEAKENING FRONT WILL STALL NEAR OR ALONG THE COAST LATER
THURSDAY NIGHT AND FRIDAY. LATEST MODEL GUIDANCE SUGGESTS FRIDAY
MAY BE A MAINLY DRY ALTHOUGH MOSTLY CLOUDY DAY.
A VIGOROUS 500MB LOW WILL MOVE EAST INTO QUEBEC LATER FRIDAY AND
SATURDAY. MODELS DIVERGE ON THE OVERALL SENSIBLE WEATHER FOR LATER
FRIDAY NIGHT AND INTO SATURDAY. THE 00Z OP RUN OF THE GFS DEVELOPS A
COMPACT SURFACE LOW ACROSS NYS FRIDAY NIGHT AND THEN TRACKS IT
ACROSS NEW ENGLAND AND ACROSS DOWNEAST MAINE FRIDAY NIGHT. 00Z EC IS
FURTHER SOUTH AND WEAKER WITH THE LOW KEEPING THE REGION MAINLY DRY.
FOR NOW HAVE KEPT CONTINUITY WITH GOING FORECAST AND WENT WITH LOW
CHANCE POPS FRIDAY NIGHT AND INTO SATURDAY.
COOLER AND DRIER AIR WILL WILL FOLLOW FOR LATE WEEKEND AND INTO
EARLY NEXT WEEK WITH TEMPERATURES AVERAGING BELOW SEASONAL FOR THIS
TIME OF YEAR.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: VFR THROUGH TONIGHT FOR ALL TERMINALS. THERE IS
POTENTIAL FOR SOME FOG TO DEVELOP LATE TONIGHT MAINLY ACROSS THE
NORTHERN TERMINALS DUE TO THE WET GROUND AND CLEARING. CONDITIONS
COULD BRIEFLY DROP TO MVFR OR PERHAPS IFR BY EARLY WEDNESDAY MORNING.
SHORT TERM: VFR WEDNESDAY. MVFR WEDNESDAY NIGHT THROUGH THURSDAY
NIGHT IN SHOWERS. VFR FRIDAY AND SATURDAY.
&&
.MARINE...
NEAR TERM: NO HEADLINES THIS TERM. WINDS WILL TURN TO THE SW LATER
TODAY AND AVERAGE 10 KT OR SO. WAVE HEIGHTS WILL STAY AT 2-3 FT
MAINLY AWAY FROM THE INTRA-COASTAL ZONE.
SHORT TERM: WINDS/SEAS SHOULD REMAIN BELOW SCA LEVELS FOR THIS
TIME OF YEAR.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HEWITT/DUDA
MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION...UPDATED
NWS BALTIMORE MD/WASHINGTON DC
822 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN PARKED OFFSHORE THROUGH THE END OF THE
WEEK. SOUTHERLY RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL
MOISTURE UP THE EASTERN SEABOARD. A COLD FRONT IS EXPECTED TO MOVE
THROUGH THE MID-ATLANTIC STATES FRIDAY NIGHT AND SATURDAY. HIGH
PRESSURE BRIEFLY BUILDS IN LATE THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...CANCELLED COASTAL FLOOD ADZY FOR ANNE ARUNDEL CO.
WIDESPREAD SHOWERS W/ EMBEDDED POCKETS OF HEAVIER RAIN WILL
CONTINUE TO SPREAD ACROSS THE I-95 CORRIDOR. HRRR SEEMS TO HAVE
THE BEST HANDLE ON THIS EVOLVING SITUATION BASED ON EARLY MORNING
RADAR TRENDS.
THIS ACTIVITY WILL COLLECT ALONG THE I-95 CORRIDOR AND THE
CHESAPEAKE BAY REGION LATER THIS MRNG...MORE SCATTERED SHOWERS AND
A FEW ISOLATED TSTMS POSSIBLE THIS AFTN/EVE.
AFTER THAT WAVE SLIDES EAST OF US BY MID TO LATE MORNING. MOST
MESOMODELS SHOW SCATTERED CONVECTION DEVELOPING IN THE WARM
ADVECTION ENVIRONMENT FOR THE AFTERNOON AND TUE NIGHT FAIRLY
EVENLY ACROSS THE FORECAST AREA. GIVEN THE WEAK AND DIFFUSE
FORCING WITH THIS...AM NOT CURRENTLY ABLE TO PUT MUCH DETAIL INTO
WHERE THE BEST CHANCES ARE IN TIME AND AREA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A CLOSED LOW WILL MEANDER OVER MANITOBA WHILE AN UPPER RIDGE IS
PARKED OVER THE GULF COAST STATES THRU THE SHORT-TERM PERIOD. UPPER
FLOW PATTERN BETWEEN THESE TWO SYSTEMS WILL BE FAIRLY ZONAL DURING
THIS TIME WITH THE MID-ATLANTIC REGION SITUATED ON SRN PERIPHERY OF
STRONGER WESTERLIES. A SERIES OF SHORTWAVE DISTURBANCES WILL ROTATE
AROUND THE BASE OF THE UPPER TROUGH WITHIN THIS BELT OF ENHANCED
WESTERLIES DURING THE SECOND HALF OF THE WEEK.
IN THE LLVLS AND AT THE SFC...SLY RETURN FLOW AROUND HIPRES OVER THE
WRN ATLANTIC WILL TRANSPORT MOISTURE FROM THE CARIBBEAN UP THE ERN
SEABOARD. PWATS INCREASE FROM AROUND 1.5 INCHES WED MRNG TO 2 INCHES
BY THU. IT WILL NOT REQUIRE A WHOLE LOT OF FORCING FROM EACH
SHORTWAVE TROUGH TO PRODUCE SHOWERS AND TSTMS IN THIS TROPICAL
AIRMASS. LOWERED POPS A BIT FROM PREV FCST WITH THE BEST FORCING
EXPECTED TO REMAIN NORTH AND WEST OF THE AREA DURING THE SHORT TERM.
POPS CLOSELY FOLLOW DIURNAL CYCLE AND ARE HIGHEST EACH DAY DURING
THE AFTN/EVE HRS. WITH EXTENSIVE CLOUD COVER OVER THE AREA...THERE
IS SOME FCST UNCERTAINTY REGARDING TSTM COVERAGE...WHICH WILL DEPEND
ON AMT OF DAYTIME HEATING. ANY STORMS WILL HAVE THE POTENTIAL TO
PRODUCE LOCALLY HVY RAINFALL...ESPECIALLY ON THU.
HUMID AIRMASS AND CLOUDS COVER WILL YIELD BELOW NORMAL HIGHS AND
ABOVE NORMAL LOWS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE VERTICALLY-STACKED LOW WILL PROGRESS SLOWLY EWD ACROSS CENTRAL
ONTARIO FRI. A LEADING SHORTWAVE DISTURBANCE ROTATING AROUND THE
BASE OF THE LARGE-SCALE TROUGH IS FCST TO MOVE FROM THE GREAT
LAKES/OH VLY TO THE NRN MID-ATLANTIC AND NORTHEAST STATES DURING
THIS TIME. THIS DISTURBANCE WILL PROVIDE SOME WEAK LIFT FOR
SHOWERS AND STORMS ESPECIALLY DURING THE PEAK HEATING HRS. YDA`S
MODELS SHOWED A COLD FRONT BECOMING STALLED OVER THE AREA ON FRI.
NOW...THE LATEST 00Z ECMWF...GFS AND ITS ENSEMBLE MEMBERS INDICATE
THE BOUNDARY REMAINING NORTH OF THE AREA. GIVEN THE SLOWING
TREND...POPS WERE LOWERED AND THE POTENTIAL FOR MORE WIDESPREAD
HEAVY RAIN NOT AS HIGH AS IT APPEARED TO BE YDA.
NONETHELESS...PWATS WILL BE ABOVE 2 INCHES...SO ANY STORMS THAT
DEVELOPS WILL BE EFFICIENT RAINFALL PRODUCERS. CONVECTION FRI AFTN
MAY FOCUS ALONG A LEE TROUGH THAT FORMS AHEAD OF THE MAIN COLD
FRONT.
THE AFOREMENTIONED SHORTWAVE TROUGH WILL MOVE ACROSS NRN NEW ENGLAND
FRI NGT. NW FLOW BEHIND THE TROUGH WILL HELP PUSH THE COLD FRONT
TOWARD THE MASON-DIXON LINE LATE FRI NGT. DIURNALLY-DRIVEN
CONVECTION EXPECTED TO WANE AFTER SUNSET.
WITH A LATER TIMING IN THE FROPA AND COOLER...DRIER AND MORE STABLE
AIR LAGGING BEHIND THE FRONT...FCST HAS TRENDED WETTER FOR THE SRN
HALF OF THE CWA ON SAT. EXPECT SHOWERS AND STORMS TO DEVELOP DURING
THE PEAK HEATING HRS. THE HIGHEST POPS RESIDE OVER THE CENTRAL VA
AND LWR SRN MD...WHICH WILL BE LOCATED CLOSEST TO LLVL CONVERGENCE
NEAR THE FRONT.
THE FRONTAL BOUNDARY IS EXPECTED TO STALL SOUTH OF THE AREA ON SUN
BEFORE LIFTING BACK NORTHWARD AS A WARM FRONT ON MON. DRY WEATHER TO
CLOSED OUT THE WEEKEND WILL BE SHORT LIVED AS SHOWERS AND STORMS
RETURN ERY NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
EXPECTING MVFR CONDITIONS TO MOVE IN THIS MORNING AND LAST INTO
WED. SHOWER THREAT WILL BE THERE..ESP FOR CHO THIS MORNING. ALSO
AN ISOLATED CHANCE FOR A TSTM.
MOIST SLY RETURN FLOW WILL BE ACCOMPANIED BY DAILY CHANCES FOR SHRA
AND TSRA DURING THE SECOND HALF OF THE WEEK. CONVECTION WILL BE
PREDOMINANTLY DIURNALLY-DRIVEN AND SCT IN NATURE. THE POTENTIAL IS
THERE FOR PERIODS OF LOW CLOUDS AND FOG EACH NGT/ERY MRNG GIVEN THE
MOIST BOUNDARY LAYER IN PLACE. A COLD FRONT MOVES THRU THE TERMINALS
FRI NGT AND SAT.
&&
.MARINE...
SCA HAS BEEN ISSUED FOR LATER TODAY INTO WED FOR THE BAY CHANNEL S
OF ANNAP AND THE LOWER TIDAL POTOMAC.
SCA HAS BEEN EXTENDED INTO WED FOR MOST OF THE MD CHSPK BAY AND THE
MOUTH OF THE TIDAL POTOMAC. SLY FETCH WILL PROMOTE CHANNELING IN
THESE ZONES.
HIPRES MOVES FARTHER OFFSHORE THU AND FRI. CHANNELING WILL STILL
ENHANCE WIND SPEEDS TO AROUND 15 KT IN THE BAY.
&&
.TIDES/COASTAL FLOODING...
SLY FLOW WILL CONTINUE THROUGH THE END OF THE WEEK AS HIGH PRESSURE
REMAINS OFF THE EAST COAST. THE HIGHER OF THE HIGH TIDE WILL BE THE
ONE TO WATCH FOR POTENTIAL MINOR TIDAL FLOODING WITH THE NEW MOON
EXPECTED MID WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM TO 6 PM EDT WEDNESDAY FOR
ANZ531-539.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 6 PM EDT
WEDNESDAY FOR ANZ532>534-537-540>543.
&&
$$
UPDATE...GMS
PREV DISCUSSION...CAS/JRK
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
401 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN PARKED OFFSHORE THROUGH THE END OF THE
WEEK. SOUTHERLY RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL
MOISTURE UP THE EASTERN SEABOARD. A COLD FRONT IS EXPECTED TO MOVE
THROUGH THE MID-ATLANTIC STATES FRIDAY NIGHT AND SATURDAY. HIGH
PRESSURE BRIEFLY BUILDS IN LATE THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
WAVE WILL COME THRU BRINGING RAIN SHOWERS MAINLY TO CENTRAL VA AND
SOUTHERN MD OVERNIGHT INTO THE MORNING...MAINTAINING THE CHANCE IT
COULD EDGE FURTHER NORTH AS IT MOVES EAST SOUTHEAST ACROSS THE
REGION. HRRR SEEMS TO HAVE THE BEST HANDLE ON THIS EVOLVING
SITUATION BASED ON EARLY MORNING RADAR TRENDS.
AFTER THAT WAVE SLIDES EAST OF US BY MID TO LATE MORNING. MOST
MESOMODELS SHOW SCATTERED CONVECTION DEVELOPING IN THE WARM
ADVECTION ENVIRONMENT FOR THE AFTERNOON AND TUE NIGHT FAIRLY
EVENLY ACROSS THE FORECAST AREA. GIVEN THE WEAK AND DIFFUSE
FORCING WITH THIS...AM NOT CURRENTLY ABLE TO PUT MUCH DETAIL INTO
WHERE THE BEST CHANCES ARE IN TIME AND AREA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A CLOSED LOW WILL MEANDER OVER MANITOBA WHILE AN UPPER RIDGE IS
PARKED OVER THE GULF COAST STATES THRU THE SHORT-TERM PERIOD. UPPER
FLOW PATTERN BETWEEN THESE TWO SYSTEMS WILL BE FAIRLY ZONAL DURING
THIS TIME WITH THE MID-ATLANTIC REGION SITUATED ON SRN PERIPHERY OF
STRONGER WESTERLIES. A SERIES OF SHORTWAVE DISTURBANCES WILL ROTATE
AROUND THE BASE OF THE UPPER TROUGH WITHIN THIS BELT OF ENHANCED
WESTERLIES DURING THE SECOND HALF OF THE WEEK.
IN THE LLVLS AND AT THE SFC...SLY RETURN FLOW AROUND HIPRES OVER THE
WRN ATLANTIC WILL TRANSPORT MOISTURE FROM THE CARIBBEAN UP THE ERN
SEABOARD. PWATS INCREASE FROM AROUND 1.5 INCHES WED MRNG TO 2 INCHES
BY THU. IT WILL NOT REQUIRE A WHOLE LOT OF FORCING FROM EACH
SHORTWAVE TROUGH TO PRODUCE SHOWERS AND TSTMS IN THIS TROPICAL
AIRMASS. LOWERED POPS A BIT FROM PREV FCST WITH THE BEST FORCING
EXPECTED TO REMAIN NORTH AND WEST OF THE AREA DURING THE SHORT TERM.
POPS CLOSELY FOLLOW DIURNAL CYCLE AND ARE HIGHEST EACH DAY DURING
THE AFTN/EVE HRS. WITH EXTENSIVE CLOUD COVER OVER THE AREA...THERE
IS SOME FCST UNCERTAINTY REGARDING TSTM COVERAGE...WHICH WILL DEPEND
ON AMT OF DAYTIME HEATING. ANY STORMS WILL HAVE THE POTENTIAL TO
PRODUCE LOCALLY HVY RAINFALL...ESPECIALLY ON THU.
HUMID AIRMASS AND CLOUDS COVER WILL YIELD BELOW NORMAL HIGHS AND
ABOVE NORMAL LOWS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE VERTICALLY-STACKED LOW WILL PROGRESS SLOWLY EWD ACROSS CENTRAL
ONTARIO FRI. A LEADING SHORTWAVE DISTURBANCE ROTATING AROUND THE
BASE OF THE LARGE-SCALE TROUGH IS FCST TO MOVE FROM THE GREAT
LAKES/OH VLY TO THE NRN MID-ATLANTIC AND NORTHEAST STATES DURING
THIS TIME. THIS DISTURBANCE WILL PROVIDE SOME WEAK LIFT FOR
SHOWERS AND STORMS ESPECIALLY DURING THE PEAK HEATING HRS. YDA`S
MODELS SHOWED A COLD FRONT BECOMING STALLED OVER THE AREA ON FRI.
NOW...THE LATEST 00Z ECMWF...GFS AND ITS ENSEMBLE MEMBERS INDICATE
THE BOUNDARY REMAINING NORTH OF THE AREA. GIVEN THE SLOWING
TREND...POPS WERE LOWERED AND THE POTENTIAL FOR MORE WIDESPREAD
HEAVY RAIN NOT AS HIGH AS IT APPEARED TO BE YDA.
NONETHELESS...PWATS WILL BE ABOVE 2 INCHES...SO ANY STORMS THAT
DEVELOPS WILL BE EFFICIENT RAINFALL PRODUCERS. CONVECTION FRI AFTN
MAY FOCUS ALONG A LEE TROUGH THAT FORMS AHEAD OF THE MAIN COLD
FRONT.
THE AFOREMENTIONED SHORTWAVE TROUGH WILL MOVE ACROSS NRN NEW ENGLAND
FRI NGT. NW FLOW BEHIND THE TROUGH WILL HELP PUSH THE COLD FRONT
TOWARD THE MASON-DIXON LINE LATE FRI NGT. DIURNALLY-DRIVEN
CONVECTION EXPECTED TO WANE AFTER SUNSET.
WITH A LATER TIMING IN THE FROPA AND COOLER...DRIER AND MORE STABLE
AIR LAGGING BEHIND THE FRONT...FCST HAS TRENDED WETTER FOR THE SRN
HALF OF THE CWA ON SAT. EXPECT SHOWERS AND STORMS TO DEVELOP DURING
THE PEAK HEATING HRS. THE HIGHEST POPS RESIDE OVER THE CENTRAL VA
AND LWR SRN MD...WHICH WILL BE LOCATED CLOSEST TO LLVL CONVERGENCE
NEAR THE FRONT.
THE FRONTAL BOUNDARY IS EXPECTED TO STALL SOUTH OF THE AREA ON SUN
BEFORE LIFTING BACK NORTHWARD AS A WARM FRONT ON MON. DRY WEATHER TO
CLOSED OUT THE WEEKEND WILL BE SHORT LIVED AS SHOWERS AND STORMS
RETURN ERY NEXT WEEK.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
EXPECTING MVFR CONDITIONS TO MOVE IN THIS MORNING AND LAST INTO
WED. SHOWER THREAT WILL BE THERE..ESP FOR CHO THIS MORNING. ALSO
AN ISOLATED CHANCE FOR A TSTM.
MOIST SLY RETURN FLOW WILL BE ACCOMPANIED BY DAILY CHANCES FOR SHRA
AND TSRA DURING THE SECOND HALF OF THE WEEK. CONVECTION WILL BE
PREDOMINANTLY DIURNALLY-DRIVEN AND SCT IN NATURE. THE POTENTIAL IS
THERE FOR PERIODS OF LOW CLOUDS AND FOG EACH NGT/ERY MRNG GIVEN THE
MOIST BOUNDARY LAYER IN PLACE. A COLD FRONT MOVES THRU THE TERMINALS
FRI NGT AND SAT.
&&
.MARINE...
SCA HAS BEEN ISSUED FOR LATER TODAY INTO WED FOR THE BAY CHANNEL S
OF ANNAP AND THE LOWER TIDAL POTOMAC.
SCA HAS BEEN EXTENDED INTO WED FOR MOST OF THE MD CHSPK BAY AND THE
MOUTH OF THE TIDAL POTOMAC. SLY FETCH WILL PROMOTE CHANNELING IN
THESE ZONES.
HIPRES MOVES FARTHER OFFSHORE THU AND FRI. CHANNELING WILL STILL
ENHANCE WIND SPEEDS TO AROUND 15 KT IN THE BAY.
&&
.TIDES/COASTAL FLOODING...
SLY FLOW WILL CONTINUE THROUGH THE END OF THE WEEK AS HIGH PRESSURE
REMAINS OFF THE EAST COAST. THE HIGHER OF THE HIGH TIDE WILL BE THE
ONE TO WATCH FOR POTENTIAL MINOR TIDAL FLOODING WITH THE NEW MOON
EXPECTED MID WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 9 AM EDT THIS MORNING FOR MDZ014.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 8 AM EDT
WEDNESDAY FOR ANZ532>534-537-540>543.
&&
$$
SYNOPSIS...JRK
NEAR TERM...CAS
SHORT TERM...JRK
LONG TERM...JRK
AVIATION...JRK/CAS
MARINE...JRK/CAS
TIDES/COASTAL FLOODING...JRK/CAS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
247 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OVER THE MID ATLANTIC STATES MOVES OFF THE COAST
TONIGHT AND TUESDAY. A WARM FRONT WILL LIFT BACK NORTH INTO THE
REGION LATE TONIGHT THROUGH TUESDAY. A MOIST AIR MASS WILL PREVAIL
THE REST OF THE WEEK...RESULTING IN DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TODAY/...
THE LATEST WATER VAPOR IMAGERY ALONG WITH 00Z UPPER AIR
OBSERVATIONS INDICATE NW MID/UPPER FLOW FROM THE UPPER MIDWEST
THROUGH THE MID ATLANTIC BETWEEN TWO PRIMARY TROUGHS OVER CENTRAL
AND ATLANTIC CANADA...AND AN UPPER RIDGE CENTERED OVER TX. WV
IMAGERY INDICATES A SHORTWAVE TROUGH DIVING ESE ACROSS THE LOWER
GREAT LAKES. WAA RETURNS AHEAD OF THIS FEATURE LATE TONIGHT ALONG
WITH ISENTROPIC LIFT AROUND THE 305-310K RANGE. IN EFFECT...THE
80H WARM FRONT WILL PASS THROUGH THE AREA TUESDAY MORNING. THIS
WILL BEGIN OVER THE MOUNTAINS OF SOUTHWEST VIRGINIA AND DEVELOP TO
THE E AND NE. THE LAST FEW RUNS OF THE RUC ALONG WITH SUPPORT FROM
THE 18Z NAM/GFS INDICATE RATHER STRONG LIFT OVER THE NW QUADRANT
OF THE CWA LATE TONIGHT INTO EARLY TUESDAY MORNING (08-12Z). GIVEN
THIS...POPS WERE RAISED TO LIKELY FOR THE NW CORNER OF THE AREA
DURING THIS TIMEFRAME. OTHERWISE...POPS REMAIN AS IS FOR REST OF
THE AREA.
LOW TEMPERATURES WILL RANGE FROM THE LOWER 60S ON THE LOWER EASTERN
SHORE TO THE MID AND UPR 60S ELSEWHERE.
ON TUESDAY...FOLLOWED CLOSE TO NAM FORECAST. BOTH THE NAM AND MOS
GUIDE HAVE THE HIGHEST POPS OVER THE FAR NORTH PART OF OUR AREA
(DORCHESTER COUNTY MD AND PART OF THE NORTHERN NECK). HAVE LIKELY
POPS IN THIS AREA THROUGH EARLY TUESDAY AFTN. A CHANCE FOR SHOWERS
AND THUNDERSTORMS WILL EXTEND ACROSS THE CWA TUESDAY AFTN WITH
LOWEST POPS (20 PERCENT) JUST ALONG THE ALBEMARLE SOUND. KEPT
THUNDERSTORM MENTION TO SLIGHT CHANCE UNTIL 18Z TUESDAY.
TEMPERATURES WILL BE HELD DOWN SOME BY CLOUD COVER AND PCPN WITH
READINGS AROUND 80 IN THE NORTH TO THE MID 80S NEAR THE VA/NC
BORDER.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
CONTINUED WITH THE CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH MOST
OF THE SHORT TERM PERIOD. MOST POPS ARE IN THE 30 TO 40 PERCENT
RANGE. DEEPEST MOISTURE APPEARS TO BE OVER THE NORTHWEST HALF OF THE
AREA. SOME LOCALLY HEAVY RAINFALL IS POSSIBLE...MAINLY WEST OF I95
AND ACROSS THE NORTHERN COUNTIES...BUT DO NOT SEE A NEED TO
HIGHLIGHT IN THE HWO AT THIS POINT.
HIGHEST CHANCES APPEAR TO BE WEDNESDAY NIGHT WHEN MOST MODELS
INDICATE A SHORT WAVE MOVING THROUGH. WITH THIS BEING IN THE FIFTH
PERIOD...HIGHEST CHANCES ARE ACROSS OUR NORTHERN AREAS...SIMILAR TO
TUESDAY MORNING. WAS NOT CONFIDENT ENOUGH WITH THE TIMING TO GO
LIKELY AT THIS POINT. HIGH TEMPERATURES WEDNESDAY ARE FORECAST TO BE
IN THE LOW TO MID 80S WEDNESDAY AND MID 80S TO NEAR 90 ON THURSDAY.
LOWS SHOULD RANGE FROM 65 TO 70.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE MODELS CONTINUE TO HANDLE THE OVERALL UPPER PATTERN
WELL. STRONG UPPER LEVEL CLOSED LOW WILL BEGIN TO EJECT EWD FRI AS A
SPEED MAX ROUNDS THE BASE OF THE LOW...AMPLIFYING A MID LEVEL TROUGH
OVER THE NE STATES. THE EJECTING LOW WILL PUSH A SFC LOW THRU SE
CANADA WITH AN ATTENDANT COLD FRONT STRETCHING SWWD INTO THE OH
VALLEY. MEANWHILE...MID LEVEL HIGH PRESSURE WILL LOCATE JUST OFF THE
SOUTHEAST COAST FRI WITH RIDGING OVER THE WRN ATLANTIC. THE RESULT
WILL BE INCREASING SW FLOW OVER THE LOCAL AREA. PRECIP WATER VALUES
PROGGED TO INCREASE AOA 2 INCHES FRI AFTERNOON WITH STRONG H85
MOISTURE TRANSPORT. SHORTWAVE ENERGY EMBEDDED IN THE WSW FLOW ALOFT
WILL PROVIDE SUBTLE FORCING FOR ASCENT FRI AFTERNOON. LEE SIDE
TROUGH AND THE APPROACHING COLD FRONT...AS WELL AS LOCAL CONVERGENCE
BOUNDARIES...WILL COMBINE WITH MID LEVEL FORCING AND ABUNDANT
MOISTURE FOR SCATTERED SHOWERS AND THUNDERSTORMS FRI AFTERNOON. THE
BEST COVERAGE WILL BE OVER THE PIEDMONT...CLOSEST TO THE FRONT AND
BEST MOISTURE. HIGH PRESSURE AND LESS MOISTURE ALONG THE COAST WILL
LIMIT PRECIP CHANCES ACROSS THE SE. AS THE UPPER LEVEL FORCING WANES
FRI NIGHT IN ADVANCE OF THE FRONT...EXPECT PRECIP CHANCES TO
DIMINISH LATE FRI NIGHT/EARLY SAT MORNING. THE FRONT WILL SAG SWD
THROUGH THE LOCAL AREA SAT. ADDITIONAL SHORTWAVE ENERGY AS WELL AS
RRQ OF 70 KT UPPER LEVEL JET WILL PROVIDE BETTER FORCING FOR ASCENT
SAT ALONG THE COLD FRONT...RESULTING IN BETTER COVERAGE (ALBEIT
CHANCE) OF SHOWERS AND THUNDERSTORMS OVER THE LOCAL AREA. REGARDLESS
OF ABUNDANT MOISTURE (+1 TO +2 STD DEV PRECIP WATER) AND LIMITED
FORCING FOR ASCENT...THE BEST DYNAMICS WILL REMAIN WELL NORTH OF THE
LOCAL AREA. THIS WILL LIKELY LIMIT THE COVERAGE OF
SHOWERS/THUNDERSTORMS...BUT LOCALLY HEAVY RAINFALL WILL STILL BE
POSSIBLE DUE TO THE VERY MOIST AIRMASS. FLOW PARALLEL TO THE FRONT
AND HIGH PRESSURE ALONG THE SE COAST WILL RESULT IN THE FRONT
SLOWING AS IT REACHES THE COAST. WILL HOLD ONTO SLIGHT CHANCE-CHANCE
POPS ACROSS THE SE SUN TO ACCOUNT FOR THE SLOWING FRONT. HIGH
PRESSURE WILL THEN BUILD IN BEHIND THE DEPARTING COLD FRONT.
HOWEVER...COLDEST AIR EXPECTED TO REMAIN NORTH OF THE LOCAL AREA.
MAIN CHANGES POST FRONTAL WILL BE DRIER AIR AND NLY WINDS.
TEMPS DURING THE EXTENDED WILL REMAIN AROUND SEASONABLE NORMS
(MID/UPPER 80S) UNDER PARTLY CLOUDY TO MOSTLY CLOUDY SKIES. MILD
OVERNIGHT TEMPS WITH LOWS GENERALLY IN THE UPPER 60S/LOW 70S. HUMID
FRI-SAT BEFORE DRYING OUT POST FRONTAL SAT NIGHT-MON.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
VFR CONDITIONS CONTINUE TO PREVAIL EARLY THIS MORNING ACROSS AREA
TERMINALS. HAVE NOTED SOME LOWERING CEILINGS OVER THE PAST 2 HOURS
AHEAD OF AN APPROACHING WARM FRONT. EXPECT BKN/OVC CONDITIONS
BETWEEN 4-6KFT BETWEEN 08-12Z. AFTER A BRIEF PERIOD OF VICINITY
SHRAS, HV CONTINUED PREDOMINATE -RA MENTION AT KRIC/KPHF/KSBY
THROUGH 12Z. DUE TO DRY AIR IN LLVLS, WILL KEEP VSBYS P6SM AND
CIGS AOA 3KFT. WINDS SHIFT FROM SE TO S/SW THIS AFTN WITH THE
POTENTIAL FOR AT LEAST SCATTERED SHRA OR TSRA BUT GIVEN
UNCERTAINTY WENT WITH ANOTHER PERIOD OF "VCSH" IN TAFS FOR NOW.
OTHERWISE...MODESTLY WARMER AND MORE HUMID AIRMASS WILL PREVAIL
FOR THE MID TO LATTER PORTION OF THE WORK WEEK. SCT (MAINLY
DIURNALLY DRIVEN) SHOWERS AND TSTMS ARE EXPECTED. COLD FRONT
SLOWLY PUSHES THROUGH ON SAT...BRINGING WITH IT CONTINUED CHANCES
FOR SHRA/TSRA.
&&
.MARINE...
LIGHT N-NE WINDS AOB 10 KT OVER THE WATERS TODAY AS HIGH PRESSURE
ORIENTS ALONG THE MID ATLANTIC COAST. HIGH PRESSURE WILL CONTINUE
TO SLIDE OFFSHORE TONIGHT AS WINDS TURN TO THE S-SE. A WARM FRONT
WILL LIFT THROUGH THE MID ATLANTIC REGION LATE TUE-WED. WINDS WILL
INCREASE BEHIND THE FRONT AS THE GRADIENT TIGHTENS BTWN HIGH
PRESSURE OFFSHORE AND LOW PRESSURE OVER THE GREAT LAKES
REGION...BUT ARE EXPECTED TO REMAIN BELOW SCA SPEEDS. SOME SLY
CHANNELING MAY LEAD TO ENHANCED WINDS OVER THE MIDDLE BAY TUES
NIGHT-WED. GRADIENT WILL REMAIN THROUGH THURS WITH SLY WINDS AOB
15 KT. S-SE WINDS OVER THE COASTAL WATERS WILL BUILD SEAS 3-5 FT
WED NIGHT-THURS OVER THE NRN COASTAL ZONES BEFORE DIMINISHING
THURS EVENING. UNSETTLED CONDITIONS WILL REMAIN OVER THE WATERS
THROUGH EARLY THIS WEEKEND AS A COLD FRONT APPROACHES FROM THE
NORTHWEST. THE FRONT IS EXPECTED TO REACH...AND STALL OVER THE
WATERS SAT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LSA
NEAR TERM...AJZ/LSA
SHORT TERM...LSA
LONG TERM...SAM
AVIATION...LKB/MAM
MARINE...SAM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
655 PM EDT TUE AUG 6 2013
.AVIATION...
//DISCUSSION...
DIURNALLY DRIVEN SHOWERS WILL FADE AT THE BEGINNING OF THE FORECAST
LEAVING DRY CONDITIONS OVERNIGHT AS NEXT AREA OF SHOWERS/STORMS WELL
TO THE WEST OVER MN/WI MOST LIKELY DROP SOUTHEAST AND BYPASS MUCH OF
LOWER MICHIGAN OVERNIGHT. RESIDUAL LOW LEVEL MOISTURE WILL BRING
PATCHY FOG BY DAYBREAK WEDNESDAY...BUT VSBYS SHOULD HOLD IN THE 4 TO
6SM RANGE. THE NEXT CHANCE OF SHRAS/TSRAS WILL COME WITH THE PASSAGE
OF A SURFACE TROUGH BETWEEN 16Z-21Z WEDNESDAY...PROGRESSING FROM
KMBS TO THE I-94 TERMINALS DURING THE COURSE OF THE AFTERNOON.
FOR DTW...WITH CURRENT CONVECTION LIFTING NORTHEAST...THE NEXT
CHANCE OF SHRAS/TSRAS WILL HOLD OFF UNTIL 20Z-22Z WEDNESDAY AS
ACTIVITY DEVELOPS ALONG AN APPROACHING SURFACE TROUGH. OTHER THAN
THIS...THE ONLY MINOR CONCERN WILL BE THE POTENTIAL OF FOG LATE
TONIGHT...BUT EVEN WITH THIS...VSBYS SHOULD REMAIN GENERALLY 5SM.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE IN CEILINGS AOB 5000 FEET WEDNESDAY AFTERNOON.
* LOW CONFIDENCE IN TIMING/COVERAGE OF THUNDERSTORMS WEDNESDAY
AFTERNOON.
&&
.PREV DISCUSSION...ISSUED 402 PM EDT TUE AUG 6 2013
SHORT TERM...THROUGH TONIGHT
CURRENT OBSERVATIONS AND SATELLITE TRENDS SHOW CLOUDS OVER
SOUTHEAST MICHIGAN...ALONG WITH RAIN SHOWERS CONTINUING TO MOVE OFF
TO THE NORTHEAST. AREAS OF RAIN SHOWERS WERE ABLE TO DEVELOP OVER
THE WESTERN CWA AND MAINTAIN MOMENTUM AS AN AREA OF 500 MB VORTICITY
MOVED THROUGH AND LOW LEVEL LAPSE RATES INCREASED TO AROUND 6.5
C/KM. A BREAK IN THE RAIN WILL BE SEEN BEFORE ANOTHER ROUND MOVES
THROUGH ROUGHLY THE SAME AREA LATE THIS AFTERNOON AND EVENING.
LATEST RUN OF THE HRRR IS ADVERTISING MORE SHOWERS BETWEEN 20Z-03Z.
HAVE SLIGHTLY INCREASED POPS IN AREAS MAINLY NORTH OF METRO DETROIT
DURING THIS TIMEFRAME. EXPECTING MODERATE RAIN SHOWERS AS WAS SEEN
THIS MORNING...WITH A SLIGHT CHANCE FOR ISOLATED THUNDERSTORMS.
EXPECTING ANY THUNDERSTORMS THAT DO DEVELOP TO REMAIN BELOW SEVERE
CRITERIA. HAVE BEEN MONITORING A SMALL BREAK IN CLOUDS OVER THE
PAST FEW HOURS WHICH HAS ALLOWED INSTABILITY TO INCREASE. LOOKING
AT THE SPC MESOANALYSIS...LOW LEVEL LAPSE RATES HAVE INCREASED TO
AROUND 7-7.5 WITH SBCAPE ONLY AROUND 500 J/KG. SHOWERS HAVE STARTED
TO DEVELOP JUST SOUTH OF THE LANSING AND WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST. CHANCES FOR PRECIPITATION WILL DIMINISH WITH THE
LOSS OF DIURNAL HEATING. OVERNIGHT...SOUTHEAST MICHIGAN WILL START
FEELING THE INFLUENCE FROM THE UPPER LEVEL JET STREAK AS THE LOW
PRESSURE CURRENTLY OVER THE UPPER MIDWEST SAGS EAST. HIGHER CLOUDS
FROM CONVECTION CURRENTLY OVER WISCONSIN WILL STREAM IN OVER SE
MICHIGAN AND WITH WINDS OUT OF THE SOUTH..WILL KEEP LOWS WARMER THAN
THE PREVIOUS MORNING. ANOTHER AREA OF VORTICITY ASSOCIATED AHEAD OF
THE COLD FRONT IS SET TO ROTATE DOWN ACROSS THE UPPER GREAT LAKES
WEDNESDAY MORNING...INCREASING THE CHANCES FOR MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS.
LONG TERM...WEDNESDAY THROUGH MONDAY
NOT MUCH CHANGE IN THE LONG TERM THROUGH THE PERIOD AS THE DOMINATE
CUTOFF UPPER LOW CONTINUES TO WOBBLE ABOUT EASTERN CANADA. MODELS
HAVE HAD AMPLE TIME TO LATCH ONTO THIS FEATURE WHICH HAS LED TO GOOD
AGREEMENT WITH THE OVERALL PATTERN. A SECOND UPPER LOW OVER THE WEST
COAST IS STEERING THE SOUTHERN STREAM OF THE JET UP FROM SOUTHERN
CALIFORNIA THROUGH THE CENTRAL PORTION OF THE CONUS TO THE GREAT
LAKES. THIS WILL BRING ABOUT SOME PHASING OF THE TWO STREAMS OVER
THE GREAT LAKES THROUGH THE WEEKEND. GENERAL NW PROGRESSIVE FLOW
WILL SEND A SERIES OF SHORTWAVES THROUGH THE REGION PRODUCING A FEW
SHOTS AT PRECIP BUT DRY AIR AND HIGH IN THE WAKE OF THE BEST FRONT
ON WEDNESDAY WILL PREVENT ANY SIGNIFICANT EVENTS.
FOR WEDNESDAY...WE MAY HAVE A COUPLE ROUNDS OF PRECIP IN THE HOPPER
AS MODELS INDICATE A MORNING COMPLEX WITH A LEAD SHORTWAVE FOLLOWED
BY A SECOND ROUND ALONG THE COLD FRONT ITSELF LATER IN THE
AFTERNOON/EVENING. BOTH THE NAM AND HRRR SUGGEST THE MORNING STORM
COMPLEX WILL TRACK GENERALLY THROUGH CHI AND IND KEEPING THE BULK OF
PRECIP TO OUR SOUTH WITH SOME MORE SCATTERED SHOWERS UP AROUND SE
MI. THIS WILL COME MORE IN LINE THROUGH THE EVENING AS WE SEE IF/HOW
THE COMPLEX ACTUALLY COMES TOGETHER. REGARDLESS THERE WILL BE A FAIR
AMOUNT OF CLOUD COVER TO CONTEND WITH EARLY IN THE DAY. AS IS
USUALLY THE CASE FOR THE AREA...THE AMOUNT OF CLOUDS AND HOW LONG
THEY STICK AROUND WILL HELP DICTATE WHERE WE STAND WITH CONVECTION
LATER IN THE DAY ALONG THE FRONT. EVEN WITH THE NAM KEEPING A FAIR
AMOUNT OF CLOUDS AROUND THROUGH THE DAY IT STILL GENERATES UP TO
1500 K/KG OF CAPE WITH 30-40 KNOTS OF BULK SHEAR. GFS IS A LITTLE
MORE BULLISH WITH CLEARING WHICH THEN ALLOWS MORE INSTABILITY TO
BUILD ADVERTISING JUST OVER 2000 J/KG OF CAPE. ANOTHER PROBLEM WITH
THE SETUP IS THAT THE PARENT SFC LOW WILL BE LIFTING TO THE NORTH
THROUGH THE DAY WHICH SLOWLY ORIENTATES THE FRONT PARALLEL TO THE
FLOW REDUCING SFC CONVERGENCE ALONG THE FRONT. LI/S ARE ON THE LOW
SIDE AS WELL ONLY REACHING AROUND -3C. FRONTAL TIMING WILL BE
FAVORABLE GIVING SE MI THE FULL DAY TO CLEAR OUT AND HEAT UP BEFORE
THE FRONT ROLLS THROUGH SO CHANCES FOR STRONG ORGANIZED STORMS WILL
GET LARGER AS YOU TRACK FROM MBS TO DTW. SPC IS ON TRACK WITH THIS
THINKING KEEPING ONLY FAR SE MI...SE OF A LINE FROM PORT HURON TO
COLDWATER...WITHIN THE SLIGHT RISK AREA. TEMPS SHOULD REACH 80+ FOR
MOST LOCATIONS AS A DECENT THETA E RIDGE BUILDS IN AHEAD OF THE
FRONT. 850 MB TEMPS ARE STILL PROGGED TO REACH 16C BY THE AFTERNOON
HOURS.
IN THE WAKE OF THE FRONT A HIGH PRESSURE SYSTEM WILL SLIDE INTO THE
REGION BRINGING COOLER DRIER AIR IN FROM CANADA THROUGH SATURDAY. A
WEAK FRONT WILL DROP THROUGH FRIDAY NIGHT WITH LITTLE CHANCE OF
PRODUCING MORE THAN A CHANCE FOR MOST LOCATIONS. A SHORTWAVE ON
SUNDAY WILL WORK OVER THE AREA BUT WILL LIKELY STRUGGLE TO PRODUCE
ANY PRECIP WITH DRY AIR PRESENT. NORTHERLY FLOW WITH THE MAIN
BAROCLINIC ZONE TO OUR SOUTH WILL KEEP TEMPERATURES ON THE COOL SIDE
THROUGH MUCH OF THE EXTENDED. THE PATTERN HAS YIELDED AN EXTENSIVE
PERIOD OF 70S AND DO NOT SEE THIS CHANGING.
MARINE...
LOW PRESSURE WILL SAG OVER THE UPPER GREAT LAKES PULLING A COLD
FRONT THROUGH THE AREA LATER WEDNESDAY EVENING. SOUTHERLY WINDS
AHEAD OF THE FRONT WILL CONTINUE OVERNIGHT AND THROUGH WEDNESDAY.
WARMER AIR ASSOCIATED WITH THE SOUTHERLY WINDS WILL KEEP CONDITIONS
STABLE OVER THE WATERS. CHANCE FOR MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL INCREASE STARTING WEDNESDAY MORNING. WINDS WILL
DIMINISH THURSDAY INTO FRIDAY AS HIGH PRESSURE OVERSPREADS THE
REGION. ANOTHER COLD FRONT IS FORECAST TO TRAVERSE THE LAKES FRIDAY
NIGHT. A PUSH OF MUCH COLDER AIR BEHIND THIS FRONT IS LIKELY TO
CAUSE STRENGTHENING OF THE POST FRONTAL NORTHWEST WINDS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....DG
SHORT TERM...SS
LONG TERM....DRK
MARINE.......SS
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
402 PM EDT TUE AUG 6 2013
.SHORT TERM...THROUGH TONIGHT
CURRENT OBSERVATIONS AND SATELLITE TRENDS SHOW CLOUDS OVER
SOUTHEAST MICHIGAN...ALONG WITH RAIN SHOWERS CONTINUING TO MOVE OFF
TO THE NORTHEAST. AREAS OF RAIN SHOWERS WERE ABLE TO DEVELOP OVER
THE WESTERN CWA AND MAINTAIN MOMENTUM AS AN AREA OF 500 MB VORTICITY
MOVED THROUGH AND LOW LEVEL LAPSE RATES INCREASED TO AROUND 6.5
C/KM. A BREAK IN THE RAIN WILL BE SEEN BEFORE ANOTHER ROUND MOVES
THROUGH ROUGHLY THE SAME AREA LATE THIS AFTERNOON AND EVENING.
LATEST RUN OF THE HRRR IS ADVERTISING MORE SHOWERS BETWEEN 20Z-03Z.
HAVE SLIGHTLY INCREASED POPS IN AREAS MAINLY NORTH OF METRO DETROIT
DURING THIS TIMEFRAME. EXPECTING MODERATE RAIN SHOWERS AS WAS SEEN
THIS MORNING...WITH A SLIGHT CHANCE FOR ISOLATED THUNDERSTORMS.
EXPECTING ANY THUNDERSTORMS THAT DO DEVELOP TO REMAIN BELOW SEVERE
CRITERIA. HAVE BEEN MONITORING A SMALL BREAK IN CLOUDS OVER THE
PAST FEW HOURS WHICH HAS ALLOWED INSTABILITY TO INCREASE. LOOKING
AT THE SPC MESOANALYSIS...LOW LEVEL LAPSE RATES HAVE INCREASED TO
AROUND 7-7.5 WITH SBCAPE ONLY AROUND 500 J/KG. SHOWERS HAVE STARTED
TO DEVELOP JUST SOUTH OF THE LANSING AND WILL CONTINUE TO MOVE OFF
TO THE NORTHEAST. CHANCES FOR PRECIPITATION WILL DIMINISH WITH THE
LOSS OF DIURNAL HEATING. OVERNIGHT...SOUTHEAST MICHIGAN WILL START
FEELING THE INFLUENCE FROM THE UPPER LEVEL JET STREAK AS THE LOW
PRESSURE CURRENTLY OVER THE UPPER MIDWEST SAGS EAST. HIGHER CLOUDS
FROM CONVECTION CURRENTLY OVER WISCONSIN WILL STREAM IN OVER SE
MICHIGAN AND WITH WINDS OUT OF THE SOUTH..WILL KEEP LOWS WARMER THAN
THE PREVIOUS MORNING. ANOTHER AREA OF VORTICITY ASSOCIATED AHEAD OF
THE COLD FRONT IS SET TO ROTATE DOWN ACROSS THE UPPER GREAT LAKES
WEDNESDAY MORNING...INCREASING THE CHANCES FOR MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS.
&&
.LONG TERM...WEDNESDAY THROUGH MONDAY
NOT MUCH CHANGE IN THE LONG TERM THROUGH THE PERIOD AS THE DOMINATE
CUTOFF UPPER LOW CONTINUES TO WOBBLE ABOUT EASTERN CANADA. MODELS
HAVE HAD AMPLE TIME TO LATCH ONTO THIS FEATURE WHICH HAS LED TO GOOD
AGREEMENT WITH THE OVERALL PATTERN. A SECOND UPPER LOW OVER THE WEST
COAST IS STEERING THE SOUTHERN STREAM OF THE JET UP FROM SOUTHERN
CALIFORNIA THROUGH THE CENTRAL PORTION OF THE CONUS TO THE GREAT
LAKES. THIS WILL BRING ABOUT SOME PHASING OF THE TWO STREAMS OVER
THE GREAT LAKES THROUGH THE WEEKEND. GENERAL NW PROGRESSIVE FLOW
WILL SEND A SERIES OF SHORTWAVES THROUGH THE REGION PRODUCING A FEW
SHOTS AT PRECIP BUT DRY AIR AND HIGH IN THE WAKE OF THE BEST FRONT
ON WEDNESDAY WILL PREVENT ANY SIGNIFICANT EVENTS.
FOR WEDNESDAY...WE MAY HAVE A COUPLE ROUNDS OF PRECIP IN THE HOPPER
AS MODELS INDICATE A MORNING COMPLEX WITH A LEAD SHORTWAVE FOLLOWED
BY A SECOND ROUND ALONG THE COLD FRONT ITSELF LATER IN THE
AFTERNOON/EVENING. BOTH THE NAM AND HRRR SUGGEST THE MORNING STORM
COMPLEX WILL TRACK GENERALLY THROUGH CHI AND IND KEEPING THE BULK OF
PRECIP TO OUR SOUTH WITH SOME MORE SCATTERED SHOWERS UP AROUND SE
MI. THIS WILL COME MORE IN LINE THROUGH THE EVENING AS WE SEE IF/HOW
THE COMPLEX ACTUALLY COMES TOGETHER. REGARDLESS THERE WILL BE A FAIR
AMOUNT OF CLOUD COVER TO CONTEND WITH EARLY IN THE DAY. AS IS
USUALLY THE CASE FOR THE AREA...THE AMOUNT OF CLOUDS AND HOW LONG
THEY STICK AROUND WILL HELP DICTATE WHERE WE STAND WITH CONVECTION
LATER IN THE DAY ALONG THE FRONT. EVEN WITH THE NAM KEEPING A FAIR
AMOUNT OF CLOUDS AROUND THROUGH THE DAY IT STILL GENERATES UP TO
1500 K/KG OF CAPE WITH 30-40 KNOTS OF BULK SHEAR. GFS IS A LITTLE
MORE BULLISH WITH CLEARING WHICH THEN ALLOWS MORE INSTABILITY TO
BUILD ADVERTISING JUST OVER 2000 J/KG OF CAPE. ANOTHER PROBLEM WITH
THE SETUP IS THAT THE PARENT SFC LOW WILL BE LIFTING TO THE NORTH
THROUGH THE DAY WHICH SLOWLY ORIENTATES THE FRONT PARALLEL TO THE
FLOW REDUCING SFC CONVERGENCE ALONG THE FRONT. LI/S ARE ON THE LOW
SIDE AS WELL ONLY REACHING AROUND -3C. FRONTAL TIMING WILL BE
FAVORABLE GIVING SE MI THE FULL DAY TO CLEAR OUT AND HEAT UP BEFORE
THE FRONT ROLLS THROUGH SO CHANCES FOR STRONG ORGANIZED STORMS WILL
GET LARGER AS YOU TRACK FROM MBS TO DTW. SPC IS ON TRACK WITH THIS
THINKING KEEPING ONLY FAR SE MI...SE OF A LINE FROM PORT HURON TO
COLDWATER...WITHIN THE SLIGHT RISK AREA. TEMPS SHOULD REACH 80+ FOR
MOST LOCATIONS AS A DECENT THETA E RIDGE BUILDS IN AHEAD OF THE
FRONT. 850 MB TEMPS ARE STILL PROGGED TO REACH 16C BY THE AFTERNOON
HOURS.
IN THE WAKE OF THE FRONT A HIGH PRESSURE SYSTEM WILL SLIDE INTO THE
REGION BRINGING COOLER DRIER AIR IN FROM CANADA THROUGH SATURDAY. A
WEAK FRONT WILL DROP THROUGH FRIDAY NIGHT WITH LITTLE CHANCE OF
PRODUCING MORE THAN A CHANCE FOR MOST LOCATIONS. A SHORTWAVE ON
SUNDAY WILL WORK OVER THE AREA BUT WILL LIKELY STRUGGLE TO PRODUCE
ANY PRECIP WITH DRY AIR PRESENT. NORTHERLY FLOW WITH THE MAIN
BAROCLINIC ZONE TO OUR SOUTH WILL KEEP TEMPERATURES ON THE COOL SIDE
THROUGH MUCH OF THE EXTENDED. THE PATTERN HAS YIELDED AN EXTENSIVE
PERIOD OF 70S AND DO NOT SEE THIS CHANGING.
&&
.MARINE...
LOW PRESSURE WILL SAG OVER THE UPPER GREAT LAKES PULLING A COLD
FRONT THROUGH THE AREA LATER WEDNESDAY EVENING. SOUTHERLY WINDS
AHEAD OF THE FRONT WILL CONTINUE OVERNIGHT AND THROUGH WEDNESDAY.
WARMER AIR ASSOCIATED WITH THE SOUTHERLY WINDS WILL KEEP CONDITIONS
STABLE OVER THE WATERS. CHANCE FOR MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL INCREASE STARTING WEDNESDAY MORNING. WINDS WILL
DIMINISH THURSDAY INTO FRIDAY AS HIGH PRESSURE OVERSPREADS THE
REGION. ANOTHER COLD FRONT IS FORECAST TO TRAVERSE THE LAKES FRIDAY
NIGHT. A PUSH OF MUCH COLDER AIR BEHIND THIS FRONT IS LIKELY TO
CAUSE STRENGTHENING OF THE POST FRONTAL NORTHWEST WINDS.
&&
.AVIATION...ISSUED 117 PM EDT TUE AUG 6 2013
//DISCUSSION...
CLOUDS AND LOW LEVEL MOISTURE WILL CONTINUE TO STREAM INTO THE AREA
THROUGH WEDNESDAY MORNING AS A COLD FRONT APPROACHES. THERE IS
ANOTHER CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS EARLY THIS
EVENING. CHANCES ARE SLIGHTLY BETTER AT PNT/FNT TAF SITES AND SO
HAVE INCLUDED THAT IN THE TAFS. HOWEVER...WITH ANY PRECIPITATION
THAT DOES DEVELOP...AM EXPECTING SHOWERS LIKE WHAT WAS SEEN EARLIER
THIS AFTERNOON DUE TO THE WARMER AIR IN THE MID LEVELS KEEPING
THINGS FROM DEVELOPING TOO MUCH. THERE IS STILL A SLIGHT CHANCE OF AN
ISOLATED THUNDERSTORM...ESPECIALLY IF BREAKS IN THE CLOUDS DEVELOP
FOR ANY LENGTH OF TIME. A BREAK IN THE PRECIPITATION WILL BE SEEN
OVERNIGHT AND WITH THE AMOUNT OF LOW LEVEL MOISTURE DO HAVE THE
POTENTIAL TO SEE AREAS OF DECREASED VISIBILITY. RAIN AND
THUNDERSTORMS WILL ONCE AGAIN AFFECT THE AREA WEDNESDAY AS THE COLD
FRONT WORKS CLOSER AND IS EXPECTED TO PUSH THROUGH AFTER 00Z
THURSDAY.
FOR DTW...CONFIDENCE IS TO LOW TO MENTION ANY THUNDERSTORMS IN THE
TAFS LATER THIS AFTERNOON...HOWEVER WILL KEEP MONITORING FOR
CHANGES. WITH THE AMOUNT OF LOW LEVEL MOISTURE STILL PRESENT
OVERNIGHT...THERE WILL BE AN INCREASED CHANCE FOR VISIBILITIES TO
DROP UNDER 6SM.
//DTW THRESHOLD THREATS...
* MODERATE CONFIDENCE IN CEILING BELOW 5000 FT OVERNIGHT.
* LOW CONFIDENCE IN TIMING/COVERAGE OF SHOWERS THIS EVENING.
* LOW CONFIDENCE IN THUNDERSTORMS LATER THIS AFTERNOON INTO EARLY EVENING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...SS
LONG TERM....DRK
MARINE.......SS
AVIATION.....SS
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
352 PM EDT TUE AUG 6 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 347 PM EDT TUE AUG 6 2013
A COLD FRONT WILL MOVE THROUGH THE NORTHERN PLAINS TONIGHT AND
APPROACH LAKE MICHIGAN TOWARDS DAYBREAK. THE FRONT WILL SWEEP
THROUGH LOWER MICHIGAN ON WEDNESDAY BRINGING COOLER AND DRIER AIR
INTO THE REGION FOR WEDNESDAY NIGHT AND THURSDAY. SHOWER AND STORMS
WILL ACCOMPANY THE FRONT BOTH TONIGHT AND WEDNESDAY. SOME OF THE
STORMS MAY BE ON THE STRONG SIDE WEDNESDAY AFTERNOON SOUTH AND EAST
OF GRAND RAPIDS. HIGHS ON WEDNESDAY WILL PUSH INTO THE UPPER 70S AND
LOWER 80S. THE UPCOMING WEEKEND LOOKS DRY WITH HIGHS IN THE 70S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 347 PM EDT TUE AUG 6 2013
MAIN CONCERNS IN THE SHORT TERM ARE RELATED TO CONVECTION TONIGHT
AND WEDNESDAY. CURRENT THINKING IS WE WILL SEE SOME SCATTERED
SHOWERS AND STORMS BETWEEN NOW AND MIDNIGHT...WITH BETTER CHANCES
OCCURRING LATE. THE LATEST HRRR GUIDANCE WOULD SUGGEST WE WILL SEE A
THUNDERSTORM COMPLEX ROLL EAST OUT OF WISCONSIN AND MOVE INTO
CENTRAL LOWER MICHIGAN OVERNIGHT. THIS SEEMS PLAUSIBLE GIVEN THE
CONFIGURATION OF THE 850MB LLJ. NOT EXPECTING SEVERE WEATHER AT THIS
TIME...BUT THE SIMULATED REFLECTIVITY IS IN THE FORM OF A SQUALL
LINE.
EXPECT SCATTERED SHOWERS AND STORMS TO BE OVER A DECENT AMOUNT OF
THE FORECAST AREA BETWEEN 09Z AND 15Z AS UPSTREAM RESIDUAL
CONVECTION SLIDES INTO LOWER MICHIGAN OR DEVELOPS OVERHEAD ON THE
LLJ.
SHOWERS AND STORMS SHOULD REFOCUS MIDDAY ALONG THE COLD FRONT THAT
SHOULD BISECT THE CWA. STRONG STORMS ARE POSSIBLE IN THE EASTERN CWA
TOMORROW AFTERNOON WITH 40 KNOTS OF DEEP LAYER SHEAR AND THE
POTENTIAL FOR SOME BREAKS IN THE OVERCAST AHEAD OF THE MORNING
STORMS. CLOUD COVER TOMORROW MORNING WILL DETERMINE THE STRENGTH OF
THE AFTERNOON CONVECTION AS DEEP MOISTURE WILL BE IN PLACE.
THE SHOWERS AND STORMS SHOULD EXIT TO THE EAST EARLY IN THE EVENING
AS THE FRONT SWEEPS THROUGH. MAINLY DRY WEATHER IS THEN FORECAST
FROM WEDNESDAY EVENING THROUGH THURSDAY NIGHT. THERE IS SOME SMALL
POTENTIAL FOR SHOWERS AND STORMS IN THE SOUTH THURSDAY NIGHT...BUT
THIS ACTIVITY MAY JUST MISS THE AREA TO THE SOUTH PER RECENT MODEL
TRENDS.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 347 PM EDT TUE AUG 6 2013
THE POLAR VORTEX OVER EASTERN CANADA WILL CONTINUE TO PLAY A ROLE IN
OUR WEATHER THROUGH THE EXTENDED PERIOD. A STRONG SHORT WAVE MOVING
ACROSS ONTARIO WILL PUSH A COLD FRONT THROUGH THE CWA FRIDAY SENDING
ANOTHER PUSH OF COOLER AIR SOUTH ACROSS THE CWA FOR THE WEEKEND. THE
LACK OF DEEP MOISTURE AND INSTABILITY WILL RESULT IN LIGHT SHOWERS
AT BEST FRIDAY.
MUCH OF THE WEEKEND LOOKS DRY WITH HIGHS IN THE MID 70S AND
DEWPOINTS IN THE 50S AS SFC HIGH PRESSURE SETTLES OVER THE GREAT
LAKES.
ANOTHER SHORT WAVE WILL DROP SOUTH FROM NORTHERN ONTARIO DURING THE
MONDAY/TUESDAY TIME FRAME. SIMILAR TO THE LAST FRONT...THERE WON/T
BE MUCH MOISTURE WITH THIS FRONT EITHER. LOW CHANCES OF SHOWERS WILL
COVER THIS TROUGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 352 PM EDT TUE AUG 6 2013
LATEST NEPH ANALYSIS SHOWS MVFR CONDITONS ACROSS MUCH OF THE
MIDWEST. ERN LWR MI WAS MAINLY VFR AND KJXN WAS JUST ON THE
EDGE...EXPLAINING WHY THEY KEEP OSCILLATING BETWEEN IFR/MVFR. GIVEN
THE SW WINDS I KEPT KJXN MVFR BUT THEY COULD CONTINUE TO OSCILLATE
THROUGH THE AFTERNOON. LIGHT SHOWERS ARE POSSIBLE ACROSS THE SRN TAF
SITES THIS AFTERNOON. OVERALL...LOOK FOR VFR TO DEVELOP BY THIS
EVENING WITH TSRA POSSIBLE OVERNIGHT AHEAD OF AN APPROACHING COLD
FRONT.
&&
.MARINE...
ISSUED AT 347 PM EDT TUE AUG 6 2013
HAVE HELD OFF ON ANY SMALL CRAFT ADVISORIES OR BEACH HAZARDS
STATEMENTS AS THE WINDS AND WAVES IN TODAY/S MODEL RUNS ARE NOT AS
SIGNIFICANT AS LAST NIGHT OR YESTERDAY. IT APPEARS AT THIS POINT IN
BOTH THE SOUTHERLY FLOW TONIGHT AND THE NORTH FLOW BEHIND THE FRONT
TOMORROW THAT WE REMAIN BELOW CRITERIA. AM A BIT CONCERNED THOUGH
BASED ON THE WINDS SEEN IN BUFKIT THAT WE WON/T INDEED BE HIGHER
BOTH TONIGHT...WEDNESDAY AND WEDNESDAY NIGHT. WE WILL SEE AS WE
PROGRESS THROUGH THE EVENING AS BUFKIT WOULD SUGGEST INCREASING
WINDS IN THE 04Z-08Z TIME FRAME. WE PLAY THINGS LOWER AT THIS POINT
BUT WATCH CAUTIOUSLY AND CLOSELY.
&&
.HYDROLOGY...
ISSUED AT 347 PM EDT TUE AUG 6 2013
NO SIGNIFICANT HYDRO ISSUES EXPECTED THROUGH THE NEXT COUPLE DAYS
WITH NEAR NORMAL FLOWS IN PLACE NOW AND FORECAST RAINFALL IS NOT
EXPECTED TO BE WIDESPREAD OR OVERLY HEAVY. RAINFALL LAST NIGHT WAS
QUITE LIMITED AS WELL SO WE ARE STARTING OFF WITH FAIRLY DRY GROUND
OVER MUCH OF THE AREA. RAINFALL IS EXPECTED TONIGHT THROUGH
WEDNESDAY...BUT IT WILL BE ASSOCIATED WITH THUNDERSTORM COMPLEXES
THAT WILL BE TRAVERSING THE AREA AT A DECENT CLIP. THE FIRST COMES
LATE TONIGHT AS STORMS THAT FIRE IN MINNESOTA THIS EVENING TRY TO
MOVE ACROSS LAKE MICHIGAN AFTER MIDNIGHT. THESE STORMS WILL LIKELY
AFFECT CENTRAL LOWER MICHIGAN. SCATTERED SHOWERS AND STORMS WILL
THEN TRAVERSE MUCH OF THE AREA LATE TONIGHT AND WEDNESDAY MORNING. A
MORE CONCENTRATED AREA OF SHOWERS AND STORMS WILL AFFECT THE EASTERN
TO SOUTHEASTERN HALF OF THE AREA WEDNESDAY AFTERNOON. WE COULD SEE
GENERAL RAINFALL AMOUNTS ON THE ORDER OF A QUARTER TO HALF INCH WITH
ISOLATED AMOUNTS AROUND AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...93
AVIATION...93
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
347 PM EDT TUE AUG 6 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 347 PM EDT TUE AUG 6 2013
A COLD FRONT WILL MOVE THROUGH THE NORTHERN PLAINS TONIGHT AND
APPROACH LAKE MICHIGAN TOWARDS DAYBREAK. THE FRONT WILL SWEEP
THROUGH LOWER MICHIGAN ON WEDNESDAY BRINGING COOLER AND DRIER AIR
INTO THE REGION FOR WEDNESDAY NIGHT AND THURSDAY. SHOWER AND STORMS
WILL ACCOMPANY THE FRONT BOTH TONIGHT AND WEDNESDAY. SOME OF THE
STORMS MAY BE ON THE STRONG SIDE WEDNESDAY AFTERNOON SOUTH AND EAST
OF GRAND RAPIDS. HIGHS ON WEDNESDAY WILL PUSH INTO THE UPPER 70S AND
LOWER 80S. THE UPCOMING WEEKEND LOOKS DRY WITH HIGHS IN THE 70S.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 347 PM EDT TUE AUG 6 2013
MAIN CONCERNS IN THE SHORT TERM ARE RELATED TO CONVECTION TONIGHT
AND WEDNESDAY. CURRENT THINKING IS WE WILL SEE SOME SCATTERED
SHOWERS AND STORMS BETWEEN NOW AND MIDNIGHT...WITH BETTER CHANCES
OCCURRING LATE. THE LATEST HRRR GUIDANCE WOULD SUGGEST WE WILL SEE A
THUNDERSTORM COMPLEX ROLL EAST OUT OF WISCONSIN AND MOVE INTO
CENTRAL LOWER MICHIGAN OVERNIGHT. THIS SEEMS PLAUSIBLE GIVEN THE
CONFIGURATION OF THE 850MB LLJ. NOT EXPECTING SEVERE WEATHER AT THIS
TIME...BUT THE SIMULATED REFLECTIVITY IS IN THE FORM OF A SQUALL
LINE.
EXPECT SCATTERED SHOWERS AND STORMS TO BE OVER A DECENT AMOUNT OF
THE FORECAST AREA BETWEEN 09Z AND 15Z AS UPSTREAM RESIDUAL
CONVECTION SLIDES INTO LOWER MICHIGAN OR DEVELOPS OVERHEAD ON THE
LLJ.
SHOWERS AND STORMS SHOULD REFOCUS MIDDAY ALONG THE COLD FRONT THAT
SHOULD BISECT THE CWA. STRONG STORMS ARE POSSIBLE IN THE EASTERN CWA
TOMORROW AFTERNOON WITH 40 KNOTS OF DEEP LAYER SHEAR AND THE
POTENTIAL FOR SOME BREAKS IN THE OVERCAST AHEAD OF THE MORNING
STORMS. CLOUD COVER TOMORROW MORNING WILL DETERMINE THE STRENGTH OF
THE AFTERNOON CONVECTION AS DEEP MOISTURE WILL BE IN PLACE.
THE SHOWERS AND STORMS SHOULD EXIT TO THE EAST EARLY IN THE EVENING
AS THE FRONT SWEEPS THROUGH. MAINLY DRY WEATHER IS THEN FORECAST
FROM WEDNESDAY EVENING THROUGH THURSDAY NIGHT. THERE IS SOME SMALL
POTENTIAL FOR SHOWERS AND STORMS IN THE SOUTH THURSDAY NIGHT...BUT
THIS ACTIVITY MAY JUST MISS THE AREA TO THE SOUTH PER RECENT MODEL
TRENDS.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 347 PM EDT TUE AUG 6 2013
THE POLAR VORTEX OVER EASTERN CANADA WILL CONTINUE TO PLAY A ROLE IN
OUR WEATHER THROUGH THE EXTENDED PERIOD. A STRONG SHORT WAVE MOVING
ACROSS ONTARIO WILL PUSH A COLD FRONT THROUGH THE CWA FRIDAY SENDING
ANOTHER PUSH OF COOLER AIR SOUTH ACROSS THE CWA FOR THE WEEKEND. THE
LACK OF DEEP MOISTURE AND INSTABILITY WILL RESULT IN LIGHT SHOWERS
AT BEST FRIDAY.
MUCH OF THE WEEKEND LOOKS DRY WITH HIGHS IN THE MID 70S AND
DEWPOINTS IN THE 50S AS SFC HIGH PRESSURE SETTLES OVER THE GREAT
LAKES.
ANOTHER SHORT WAVE WILL DROP SOUTH FROM NORTHERN ONTARIO DURING THE
MONDAY/TUESDAY TIME FRAME. SIMILAR TO THE LAST FRONT...THERE WON/T
BE MUCH MOISTURE WITH THIS FRONT EITHER. LOW CHANCES OF SHOWERS WILL
COVER THIS TROUGH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 752 AM EDT TUE AUG 6 2013
NUMEROUS MVFR CIGS AND SCATTERED RAIN SHOWERS THIS MORNING SHOULD
TRANSITION TO PRIMARILY VFR CONDITIONS FOR THIS AFTERNOON INTO
THIS EVENING. MORNING STRATUS DECK WITH BASES OF 1500-2500 FT IS
EXPECTED TO LIFT TO A DIURNAL CUMULUS DECK WITH BASES AROUND 3500
FT THIS AFTERNOON. SOME IFR CIGS ARE POSSIBLE THROUGH MID MORNING
WEST OF HWY 131 INCLUDING MKG.
WHILE THE THUNDER THREAT IS NOT ZERO THIS AFTERNOON AND EVENING...
PROBABLY THE BEST CHANCE OF TSTMS WILL COME LATE TONIGHT AFTER 06Z
ESPECIALLY ALONG AND WEST OF HWY 131.
&&
.MARINE...
ISSUED AT 347 PM EDT TUE AUG 6 2013
HAVE HELD OFF ON ANY SMALL CRAFT ADVISORIES OR BEACH HAZARDS
STATEMENTS AS THE WINDS AND WAVES IN TODAY/S MODEL RUNS ARE NOT AS
SIGNIFICANT AS LAST NIGHT OR YESTERDAY. IT APPEARS AT THIS POINT IN
BOTH THE SOUTHERLY FLOW TONIGHT AND THE NORTH FLOW BEHIND THE FRONT
TOMORROW THAT WE REMAIN BELOW CRITERIA. AM A BIT CONCERNED THOUGH
BASED ON THE WINDS SEEN IN BUFKIT THAT WE WON/T INDEED BE HIGHER
BOTH TONIGHT...WEDNESDAY AND WEDNESDAY NIGHT. WE WILL SEE AS WE
PROGRESS THROUGH THE EVENING AS BUFKIT WOULD SUGGEST INCREASING
WINDS IN THE 04Z-08Z TIME FRAME. WE PLAY THINGS LOWER AT THIS POINT
BUT WATCH CAUTIOUSLY AND CLOSELY.
&&
.HYDROLOGY...
ISSUED AT 347 PM EDT TUE AUG 6 2013
NO SIGNIFICANT HYDRO ISSUES EXPECTED THROUGH THE NEXT COUPLE DAYS
WITH NEAR NORMAL FLOWS IN PLACE NOW AND FORECAST RAINFALL IS NOT
EXPECTED TO BE WIDESPREAD OR OVERLY HEAVY. RAINFALL LAST NIGHT WAS
QUITE LIMITED AS WELL SO WE ARE STARTING OFF WITH FAIRLY DRY GROUND
OVER MUCH OF THE AREA. RAINFALL IS EXPECTED TONIGHT THROUGH
WEDNESDAY...BUT IT WILL BE ASSOCIATED WITH THUNDERSTORM COMPLEXES
THAT WILL BE TRAVERSING THE AREA AT A DECENT CLIP. THE FIRST COMES
LATE TONIGHT AS STORMS THAT FIRE IN MINNESOTA THIS EVENING TRY TO
MOVE ACROSS LAKE MICHIGAN AFTER MIDNIGHT. THESE STORMS WILL LIKELY
AFFECT CENTRAL LOWER MICHIGAN. SCATTERED SHOWERS AND STORMS WILL
THEN TRAVERSE MUCH OF THE AREA LATE TONIGHT AND WEDNESDAY MORNING. A
MORE CONCENTRATED AREA OF SHOWERS AND STORMS WILL AFFECT THE EASTERN
TO SOUTHEASTERN HALF OF THE AREA WEDNESDAY AFTERNOON. WE COULD SEE
GENERAL RAINFALL AMOUNTS ON THE ORDER OF A QUARTER TO HALF INCH WITH
ISOLATED AMOUNTS AROUND AN INCH.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...93
AVIATION...MEADE
HYDROLOGY...DUKE
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
324 PM EDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 548 AM EDT TUE AUG 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN UNUSUALLY DEEP VORTEX
FOR EARLY AUG CENTERED JUST S OF HUDSON BAY ALONG THE
MANITOBA/ONTARIO BORDER. ACROSS THE UPPER LAKES...FLOW HAS BECOME
MORE WESTERLY OVER THE LAST DAY OR TWO IN RESPONSE TO THE
DEEPENING/EXPANDING VORTEX THAT HAS BEEN DRIFTING S. SEVERAL
SHORTWAVES ARE EVIDENT UPSTREAM WITH 2 MORE NOTABLE WAVES OVER ERN
MT/SRN SASKATCHEWAN AND OVER ERN ALBERTA. THESE 2 WAVES WILL POWER A
COLD FRONT ACROSS UPPER MI TONIGHT AND WEDNESDAY MORNING. CLOSER TO
HOME...ISOLD/SCT SHRA (EVEN ISOLD TSRA AT TIMES) HAVE BEEN OCCURRING
OVER THE LAST SEVERAL HRS OVER WRN UPPER MI/ADJACENT LAKE SUPERIOR.
THESE SHRA ARE JUST AHEAD OF A 700MB TROF AND SURGE OF MIDLEVEL
DRYING PER BY LATEST RUC.
FOCUS EARLY THIS MORNING WILL BE ON THE ISOLD/SCT SHRA OVER THE W.
AS AFOREMENTIONED 700MB TROF CONTINUES TO PUSH E...WILL PROBABLY
CONTINUE TO SEE SOME SHRA SPREAD E INTO CNTRL UPPER MI OVER THE NEXT
SEVERAL HRS. LATEST SPC MESOANALYSIS SHOWS MUCAPE AROUND 250J/KG...
SO THERE MIGHT BE AN OCNL LIGHTNING STRIKE THOUGH THERE HAS NOT BEEN
ANY CG STRIKES FOR THE LAST COUPLE OF HRS. AS THE TROF CONTINUES
EASTWARD...IT WILL COINCIDE WITH THE HEATING CYCLE AND SHOULD AID
SHRA/TSRA DEVELOPMENT OVER THE ERN PART OF THE FCST AREA LATE THIS
MORNING/EARLY THIS AFTN...ESPECIALLY INLAND FROM LAKE MICHIGAN. SOME
HIGH RES GUIDANCE (NAM NEST AND RUC13) INDICATE LAKE BREEZE WILL
DEVELOP OFF LAKE SUPERIOR OVER THE E...BUT WILL MAKE LIMITED INLAND
PROGRESS. IF SO...CONVERGENCE ZONE WILL BE A GOOD FOCAL POINT FOR
CONVECTION. TO THE W ACROSS THE W HALF OF UPPER MI...THE SAME HIGH
RES GUIDANCE POINTS TO A MORE ACTIVE INLAND PUSH OF LAKE SUPERIOR
LAKE BREEZE. IN THE FLOW UPSTREAM...THERE ARE PROBABLY SOME SUBTLE
SHORTWAVES PRESENT GIVEN THE SCT CLUSTERS OF SHRA/TSRA THAT WERE
PRESENT EARLIER IN THE NIGHT ACROSS THE NRN PLAINS. WITH EXPECTATION
OF LOW CLOUDS CLEARING OUT/TRANSITIONING TO CU FIELD...DAYTIME
HEATING WILL LIKELY BE SUFFICIENT TO RAISE MLCAPE TO 500J/KG OR SO
PER NAM/GFS. LAKE BREEZE AND ANY SUBTLE SHORTWAVES SHOULD THEN
SUPPORT SCT SHRA/TSRA DEVELOPMENT. WITH DEEP LAYER SHEAR AROUND
35KT...SOME ORGANIZED/STRONGER STORMS ARE POSSIBLE. IF CAPE ENDS UP
HIGHER THAN CURRENTLY EXPECTED...THERE MIGHT BE AN ISOLD SVR STORM
OR TWO.
TONIGHT...THE STRONGER SHORTWAVES WELL UPSTREAM WILL PUSH A COLD
FRONT INTO UPPER MI. AS HAS BEEN THE CASE FOR THE LAST SEVERAL
DAYS...MODELS CONTINUE TO POINT TOWARD A GOOD POTENTIAL OF SHRA/TSRA
SPREADING ACROSS THE FCST AREA. WITH RATHER VIGOROUS DEEP LAYER
FORCING...STRONG MOISTURE TRANSPORT AND SHARP LOW LEVEL TROF
SHIFTING E...WILL RETAIN LIKELY POPS SPREADING E ACROSS THE AREA
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 548 AM EDT TUE AUG 6 2013
AMPLIFIED UPPER AIR PATTERN PERSISTS THROUGH THE UPCOMING WEEKEND
AND LIKELY INTO NEXT WEEK AS WELL. MEAN TROUGHING DOMINATES MUCH OF
EASTERN CANADA ACROSS THE GREAT LAKES. PRIMARY RESULT OF THIS
PATTERN WILL BE CONTINUATION OF COOLER THAN NORMAL TEMPERATURES
THROUGH AT LEAST MID AUGUST ACROSS UPPER GREAT LAKES REGION. TO
START OUT ON WEDNESDAY...MAIN FEATURES ALOFT ARE CLOSED OFF UPPER
LOW CENTERED ALONG MANITOBA AND NORTHERN ONTARIO BORDER...SHARP WEST
TO EAST RIDGE OVER FAR NORTHERN CANADA AND A DOUBLE BARRELED TROUGH
EXTENDING FROM THE NORTH POLE SOUTHWEST ACROSS ALASKA AND TO THE
NORTHERN PORTIONS OF PACIFIC OCEAN. NOT A WHOLE LOT OF CHANGE WRT
LOCATIONS OF SAID FEATURES THROUGH THE LONG TERM. ONLY THING THAT
DOES CHANGE IS UPPER LOW OVER ONTARIO SLIDES ACROSS QUEBEC THIS
WEEKEND AS STRONGER JET ENERGY BECOMES PLACED OUT AHEAD OF THE
TROUGH...KEEPING IT MORE PROGRESSIVE. MAIN CHANCE OF RAIN IN THIS
PATTERN WILL BE RIGHT OFF THE BAT ON WEDNESDAY MORNING OVER EAST
HALF OF CWA AS COLD FRONT MOVES THROUGH REGION. ADDITIONAL CHANCES
OF RAIN POSSIBLE THURSDAY NIGHT INTO FRIDAY AS SECONDARY LOW PRESSURE
SYSTEM AND COLD FRONT CROSS THE AREA. GENERALLY LOOKS QUIET THROUGH
THE WEEKEND...BUT COOL. NEXT CHANCE OF RAIN PROBABLY ARRIVES LATER
SUNDAY NIGHT INTO MONDAY AS SHORTWAVES DROP ACROSS AREA IN NW FLOW
ALOFT.
COLD FRONT SHOULD BE OVER CNTRL UPR MICHIGAN TO START THE DAY ON
WEDNESDAY...QUICKLY HEADING EAST TO AROUND ERY BTWN 15Z-18Z. NAM
STILL ON THE FAST SIDE...WHILE ECMWF IS SLOWEST. COMPROMISE SOLN
WITH FRONT IS THE GFS/GEM-REGIONAL AS WELL AS NCEP WRF-ARW/NMM.
MAJORITY OF WIDESPREAD SHRA/TSRA WILL BE ALONG AND AHEAD OF FRONT
IN WARM AIR ADVECTION REGIME. GOING FCST LOOKS PRETTY GOOD.
CHANGES TO POPS ON WEDNESDAY WITH FROPA PRETTY MINIMAL. KEPT
LIKELY POPS OVR FAR EAST THROUGH 15Z...THEN TRIMMED BACK QUICKLY
WITH ARRIVAL OF STRONG MID-LEVEL DRYING AND AS PRIMARY H85 MOISTURE
ADVECTION IS EAST OF CWA. SOUNDINGS INDICATE LINGERING LOW-LEVEL
MOISTURE BEHIND COLD FRONT THAT COULD LEAD TO BRIEF PERIOD OF LGT
RAIN/DRIZZLE IN THE MORNING FOR AREAS NEAR LK SUPERIOR.
EVENTUALLY...BLYR BECOMING MIXED ALONG WITH NEGATIVE SFC-H85 THETA-E
ADVECTION WILL SHUT DOWN ANY LINGERING PRECIP BY MIDDAY. HAVE NO
POPS AFTER 18Z WHICH WAS A BIT OF A CHANGE COMPARED TO PREVIOUS
FCST. BKN CU/SC DECK MAY REMAIN LONGER THAN THIS...BUT EVEN THAT
SHOULD TEND TO MIX OUT TO PARTLY CLOUDY SKIES BY MID-LATE AFTN.
TEMPS TRICKY WITH FROPA AS 925-850MB TEMPS JUST AHEAD OF FRONT ARE
PRETTY WARM. FIGURING OUT HOW THE WARM AIR BALANCES BTWN COOLING
FROM CLOUDS/PRECIP IS MAIN HURDLE. WILL GO FOR MAX TEMPS TOPPING OUT
IN THE LOW 70S...WARMEST SOUTH CENTRAL. TEMPS ALONG LK SUPERIOR
COULD RISE EARLY ON...BUT THEN FALL BACK IN THE AFTN WITH INCREASING
ONSHORE FLOW. SHOULD BE ESPECIALLY NOTABLE NEAR MQT-P53. FOG THAT IS
DEVELOPING ACROSS LK SUPERIOR CURRENTLY MAY GET SHOVED ONSHORE TOO
FOR A WHILE.
SFC HIGH RIDGES IN FROM CANADIAN PRAIRIE PROVINCES WEDNESDAY NIGHT
INTO THURSDAY AHEAD OF NEXT COLD FRONT. H85 WINDS STAY ONSHORE ALL
NIGHT...BUT LOWEST LEVEL WINDS THROUGH 900MB BECOME LESS
SO...ALLOWING POTENTIAL FOR TYPICAL COOL SPOTS INLAND FROM THE GREAT
LAKES TO SEE TEMPS FALL INTO THE LOWER 40S. LIGHT GRADIENT WINDS ON
THURSDAY ALLOWS IN LIGHT LAKE BREEZES ALONG BOTH SUPERIOR AND
MICHIGAN. AWAY FM LOCAL COOLING THOUGH...TEMPS SHOULD BOUNCE BACK
INTO AT LEAST THE LOWER 70S MOST AREAS GIVEN H85 TEMPS WARMER THAN
+10C. THICKENING MID CLOUDS /H6-H5/ FOR WEST HALF BY AFTN AS WARM
AIR ADVECTION DEVELOPS AHEAD OF THE COLD FRONT. GFS HAS SHOWED
STEADY TREND IN BACKING OFF QPF INTO WESTERN TIER. USED A BLEND OF
MORE CONSISTENT ECMWF AND THE DRIER TRENDING GFS. RESULT WAS SOME
LOWER CHANCE POPS FOR WESTERN LK SUPERIOR/ISLE ROYALE ON NOSE OF
H85-H7 MOISTURE ADVECTION. AS SFC LOW SPINS OVER NORTHERN ONTARIO
THE COLD FRONT WILL SLOWLY SINK NORTH TO SOUTH ACROSS LK SUPERIOR
ON THURSDAY NIGHT. BEST CHANCE FOR SHRA/ISOLD TSRA WILL BE OVR LK
SUPERIOR DUE TO H85 TEMP ADVECTION/WEAK LOW-LEVEL JET AND SOME
LOW-LEVEL FRONTAL CONVERGENCE. TEMPS WILL BE ON THE MILD SIDE
AGAIN WITH SOUTH WINDS/WARM AIR ADVECTION AHEAD OF FRONT. COLD
FRONT WORKS ACROSS UPR MICHIGAN ON FRIDAY...SO WILL KEEP WITH
SOME LOWER CHANCE POPS. COOLING BEGINS ON FRIDAY...ESPECIALLY NEAR
LK SUPERIOR. INLAND...TEMPS MAY END UP ONLY A COUPLE DEGREES COOLER
THAN THURSDAY.
STRONG DRYING BEHIND FRONT FOR FRIDAY NIGHT AND SATURDAY. JUST SOME
SCT CU SHOULD DEVELOP DURING PEAK HEATING ON SATURDAY. H85 TEMPS
ONLY UP TO +6C WITH STRONGER ONSHORE FLOW WILL LEAD TO A COOL DAY
BY AUGUST STANDARDS WITH READINGS IN THE UPPER 50S/NEAR 60 ALONG LK
SUPERIOR AND MAYBE REACHING 70 DEGREES IN THE FAR SOUTH CENTRAL NEAR
MNM. 60S ELSEWHERE...WHICH IS AT LEAST 10 DEGREES BLO NORMAL.
NOT MUCH IN WAY OF CHANGES TO REST OF CONSENSUS GRIDS FOR EXTENDED.
SLIGHT CHANCE POPS FOR SUNDAY...THOUGH THESE ARE BIASED BY A LATEST
GFS WHICH TRENDED MUCH WETTER FOR PARTS OF CWA COMPARED TO PREVIOUS
RUNS. ECMWF INDICATES SMALL CHANCES OF INSTABILITY SHRA/TSRA AS
ANOTHER STRONGER WAVE OR TWO /CURRENTLY WITHIN THE LARGER TROUGH FM
ALASKA TO THE NORTH POLE/ DROPS ACROSS UPPER LAKES. POCKET OF STEEPER
MID-LEVEL LAPSE RATES WOULD JUSTIFY AT LEAST A MENTION OF TSRA DURING
PEAK HEATING OF SUNDAY AFTN LINGERING INTO SUN EVENING. SIMILAR SETUP
FOR MONDAY THOUGH BY THAT TIME BETTER FORCING IS SLIDING EAST AND
SOUTH OF LK SUPERIOR REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1151 AM EDT TUE AUG 6 2013
SLIGHTLY DRIER AIR ACROSS NE MN THIS MORNING HAS HAD A DIFFICULT
TIME MOVING INTO UPPER MI. EVEN WITH ABUNDANT LOW LEVEL
MOISTURE...AND AN ADDITIONAL PUSH OUT OF WI ON S-SW WINDS...CEILINGS
HAVE BEEN ABLE TO SLOWLY RISE INTO MVFR CATEGORY THANKS IN PART TO
BETTER MIXING /DAYTIME HEATING/. VFR CONDITIONS WILL BE POSSIBLE
THIS AFTERNOON AHEAD OF A COLD FRONT NEARING FROM MN...WITH
DETERIORATING CONDITIONS AGAIN BY THE MID-LATE EVENING HOURS. THERE
IS A POTENTIAL FOR A BROKEN LINE OF POP UP SHOWERS AND THUNDERSTORMS
OVER MAINLY CENTRAL AND E UPPER MI THIS AFTERNOON. WILL KEEP MENTION
OF VCSH AT SAW...WITH THE POTENTIAL OF ADDING TS/CB IF ANYTHING
LOOKS MORE CERTAIN. COLD FRONT WILL MOVE INTO UPPER MI
TONIGHT...BRINGING A PERIOD OF SHRA/TS AND A RETURN TO MVFR AND
POSSIBLY IFR CONDITIONS. ONCE FRONT PASSES...UPSLOPE FLOW AT
KIWD/KCMX AND TO A LESSER EXTENT SAW WILL RESULT IN LIFR CONDITIONS
WHICH WILL LINGER THROUGH THE MID MORNING HOURS BEFORE QUICKLY
CLEARING DURING THE MID-LATE MORNING HOURS W TO E.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 323 PM EDT TUE AUG 6 2013
WIND GUSTS SHOULD REMAIN AT OR BELOW 25KTS...WITH THE STRONGEST
GUSTS OUT OF THE W TO NW EXPECTED LATE TONIGHT THROUGH WEDNESDAY
CENTRAL AND EAST...AND AGAIN FRIDAY AFTERNOON AND EVENING BEHIND A
COUPLE OF COLD FRONT SWINGING ACROSS LAKE SUPERIOR. LOW PRESSURE
ACROSS WESTERN LAKE SUPERIOR WILL CONTINUE ACROSS LAKE SUPERIOR
THROUGH WEDNESDAY MORNING. PATCHY TO AREAS OF FOG SHOULD DIMINISH IN
COVERAGE DURING THE DAY WEDNESDAY AS DRIER AIR SLIDES OVERHEAD.
EXPECT HIGH PRESSURE TO BUILD EAST INTO THE UPPER GREAT LAKES BY
THURSDAY MORNING. AS THE HIGH SHIFTS EAST...A TROUGH WILL MOVE
ACROSS LAKE SUPERIOR THURSDAY NIGHT THROUGH FRIDAY MORNING. HIGH
PRESSURE WILL THEN BUILD SOUTHEAST INTO THE UPPER MISSISSIPPI VALLEY
SATURDAY...AND LINGER ACROSS THE REGION THROUGH SUNDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1152 AM EDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 548 AM EDT TUE AUG 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN UNUSUALLY DEEP VORTEX
FOR EARLY AUG CENTERED JUST S OF HUDSON BAY ALONG THE
MANITOBA/ONTARIO BORDER. ACROSS THE UPPER LAKES...FLOW HAS BECOME
MORE WESTERLY OVER THE LAST DAY OR TWO IN RESPONSE TO THE
DEEPENING/EXPANDING VORTEX THAT HAS BEEN DRIFTING S. SEVERAL
SHORTWAVES ARE EVIDENT UPSTREAM WITH 2 MORE NOTABLE WAVES OVER ERN
MT/SRN SASKATCHEWAN AND OVER ERN ALBERTA. THESE 2 WAVES WILL POWER A
COLD FRONT ACROSS UPPER MI TONIGHT AND WEDNESDAY MORNING. CLOSER TO
HOME...ISOLD/SCT SHRA (EVEN ISOLD TSRA AT TIMES) HAVE BEEN OCCURRING
OVER THE LAST SEVERAL HRS OVER WRN UPPER MI/ADJACENT LAKE SUPERIOR.
THESE SHRA ARE JUST AHEAD OF A 700MB TROF AND SURGE OF MIDLEVEL
DRYING PER BY LATEST RUC.
FOCUS EARLY THIS MORNING WILL BE ON THE ISOLD/SCT SHRA OVER THE W.
AS AFOREMENTIONED 700MB TROF CONTINUES TO PUSH E...WILL PROBABLY
CONTINUE TO SEE SOME SHRA SPREAD E INTO CNTRL UPPER MI OVER THE NEXT
SEVERAL HRS. LATEST SPC MESOANALYSIS SHOWS MUCAPE AROUND 250J/KG...
SO THERE MIGHT BE AN OCNL LIGHTNING STRIKE THOUGH THERE HAS NOT BEEN
ANY CG STRIKES FOR THE LAST COUPLE OF HRS. AS THE TROF CONTINUES
EASTWARD...IT WILL COINCIDE WITH THE HEATING CYCLE AND SHOULD AID
SHRA/TSRA DEVELOPMENT OVER THE ERN PART OF THE FCST AREA LATE THIS
MORNING/EARLY THIS AFTN...ESPECIALLY INLAND FROM LAKE MICHIGAN. SOME
HIGH RES GUIDANCE (NAM NEST AND RUC13) INDICATE LAKE BREEZE WILL
DEVELOP OFF LAKE SUPERIOR OVER THE E...BUT WILL MAKE LIMITED INLAND
PROGRESS. IF SO...CONVERGENCE ZONE WILL BE A GOOD FOCAL POINT FOR
CONVECTION. TO THE W ACROSS THE W HALF OF UPPER MI...THE SAME HIGH
RES GUIDANCE POINTS TO A MORE ACTIVE INLAND PUSH OF LAKE SUPERIOR
LAKE BREEZE. IN THE FLOW UPSTREAM...THERE ARE PROBABLY SOME SUBTLE
SHORTWAVES PRESENT GIVEN THE SCT CLUSTERS OF SHRA/TSRA THAT WERE
PRESENT EARLIER IN THE NIGHT ACROSS THE NRN PLAINS. WITH EXPECTATION
OF LOW CLOUDS CLEARING OUT/TRANSITIONING TO CU FIELD...DAYTIME
HEATING WILL LIKELY BE SUFFICIENT TO RAISE MLCAPE TO 500J/KG OR SO
PER NAM/GFS. LAKE BREEZE AND ANY SUBTLE SHORTWAVES SHOULD THEN
SUPPORT SCT SHRA/TSRA DEVELOPMENT. WITH DEEP LAYER SHEAR AROUND
35KT...SOME ORGANIZED/STRONGER STORMS ARE POSSIBLE. IF CAPE ENDS UP
HIGHER THAN CURRENTLY EXPECTED...THERE MIGHT BE AN ISOLD SVR STORM
OR TWO.
TONIGHT...THE STRONGER SHORTWAVES WELL UPSTREAM WILL PUSH A COLD
FRONT INTO UPPER MI. AS HAS BEEN THE CASE FOR THE LAST SEVERAL
DAYS...MODELS CONTINUE TO POINT TOWARD A GOOD POTENTIAL OF SHRA/TSRA
SPREADING ACROSS THE FCST AREA. WITH RATHER VIGOROUS DEEP LAYER
FORCING...STRONG MOISTURE TRANSPORT AND SHARP LOW LEVEL TROF
SHIFTING E...WILL RETAIN LIKELY POPS SPREADING E ACROSS THE AREA
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 548 AM EDT TUE AUG 6 2013
AMPLIFIED UPPER AIR PATTERN PERSISTS THROUGH THE UPCOMING WEEKEND
AND LIKELY INTO NEXT WEEK AS WELL. MEAN TROUGHING DOMINATES MUCH OF
EASTERN CANADA ACROSS THE GREAT LAKES. PRIMARY RESULT OF THIS
PATTERN WILL BE CONTINUATION OF COOLER THAN NORMAL TEMPERATURES
THROUGH AT LEAST MID AUGUST ACROSS UPPER GREAT LAKES REGION. TO
START OUT ON WEDNESDAY...MAIN FEATURES ALOFT ARE CLOSED OFF UPPER
LOW CENTERED ALONG MANITOBA AND NORTHERN ONTARIO BORDER...SHARP WEST
TO EAST RIDGE OVER FAR NORTHERN CANADA AND A DOUBLE BARRELED TROUGH
EXTENDING FROM THE NORTH POLE SOUTHWEST ACROSS ALASKA AND TO THE
NORTHERN PORTIONS OF PACIFIC OCEAN. NOT A WHOLE LOT OF CHANGE WRT
LOCATIONS OF SAID FEATURES THROUGH THE LONG TERM. ONLY THING THAT
DOES CHANGE IS UPPER LOW OVER ONTARIO SLIDES ACROSS QUEBEC THIS
WEEKEND AS STRONGER JET ENERGY BECOMES PLACED OUT AHEAD OF THE
TROUGH...KEEPING IT MORE PROGRESSIVE. MAIN CHANCE OF RAIN IN THIS
PATTERN WILL BE RIGHT OFF THE BAT ON WEDNESDAY MORNING OVER EAST
HALF OF CWA AS COLD FRONT MOVES THROUGH REGION. ADDITIONAL CHANCES
OF RAIN POSSIBLE THURSDAY NIGHT INTO FRIDAY AS SECONDARY LOW PRESSURE
SYSTEM AND COLD FRONT CROSS THE AREA. GENERALLY LOOKS QUIET THROUGH
THE WEEKEND...BUT COOL. NEXT CHANCE OF RAIN PROBABLY ARRIVES LATER
SUNDAY NIGHT INTO MONDAY AS SHORTWAVES DROP ACROSS AREA IN NW FLOW
ALOFT.
COLD FRONT SHOULD BE OVER CNTRL UPR MICHIGAN TO START THE DAY ON
WEDNESDAY...QUICKLY HEADING EAST TO AROUND ERY BTWN 15Z-18Z. NAM
STILL ON THE FAST SIDE...WHILE ECMWF IS SLOWEST. COMPROMISE SOLN
WITH FRONT IS THE GFS/GEM-REGIONAL AS WELL AS NCEP WRF-ARW/NMM.
MAJORITY OF WIDESPREAD SHRA/TSRA WILL BE ALONG AND AHEAD OF FRONT
IN WARM AIR ADVECTION REGIME. GOING FCST LOOKS PRETTY GOOD.
CHANGES TO POPS ON WEDNESDAY WITH FROPA PRETTY MINIMAL. KEPT
LIKELY POPS OVR FAR EAST THROUGH 15Z...THEN TRIMMED BACK QUICKLY
WITH ARRIVAL OF STRONG MID-LEVEL DRYING AND AS PRIMARY H85 MOISTURE
ADVECTION IS EAST OF CWA. SOUNDINGS INDICATE LINGERING LOW-LEVEL
MOISTURE BEHIND COLD FRONT THAT COULD LEAD TO BRIEF PERIOD OF LGT
RAIN/DRIZZLE IN THE MORNING FOR AREAS NEAR LK SUPERIOR.
EVENTUALLY...BLYR BECOMING MIXED ALONG WITH NEGATIVE SFC-H85 THETA-E
ADVECTION WILL SHUT DOWN ANY LINGERING PRECIP BY MIDDAY. HAVE NO
POPS AFTER 18Z WHICH WAS A BIT OF A CHANGE COMPARED TO PREVIOUS
FCST. BKN CU/SC DECK MAY REMAIN LONGER THAN THIS...BUT EVEN THAT
SHOULD TEND TO MIX OUT TO PARTLY CLOUDY SKIES BY MID-LATE AFTN.
TEMPS TRICKY WITH FROPA AS 925-850MB TEMPS JUST AHEAD OF FRONT ARE
PRETTY WARM. FIGURING OUT HOW THE WARM AIR BALANCES BTWN COOLING
FROM CLOUDS/PRECIP IS MAIN HURDLE. WILL GO FOR MAX TEMPS TOPPING OUT
IN THE LOW 70S...WARMEST SOUTH CENTRAL. TEMPS ALONG LK SUPERIOR
COULD RISE EARLY ON...BUT THEN FALL BACK IN THE AFTN WITH INCREASING
ONSHORE FLOW. SHOULD BE ESPECIALLY NOTABLE NEAR MQT-P53. FOG THAT IS
DEVELOPING ACROSS LK SUPERIOR CURRENTLY MAY GET SHOVED ONSHORE TOO
FOR A WHILE.
SFC HIGH RIDGES IN FROM CANADIAN PRAIRIE PROVINCES WEDNESDAY NIGHT
INTO THURSDAY AHEAD OF NEXT COLD FRONT. H85 WINDS STAY ONSHORE ALL
NIGHT...BUT LOWEST LEVEL WINDS THROUGH 900MB BECOME LESS
SO...ALLOWING POTENTIAL FOR TYPICAL COOL SPOTS INLAND FROM THE GREAT
LAKES TO SEE TEMPS FALL INTO THE LOWER 40S. LIGHT GRADIENT WINDS ON
THURSDAY ALLOWS IN LIGHT LAKE BREEZES ALONG BOTH SUPERIOR AND
MICHIGAN. AWAY FM LOCAL COOLING THOUGH...TEMPS SHOULD BOUNCE BACK
INTO AT LEAST THE LOWER 70S MOST AREAS GIVEN H85 TEMPS WARMER THAN
+10C. THICKENING MID CLOUDS /H6-H5/ FOR WEST HALF BY AFTN AS WARM
AIR ADVECTION DEVELOPS AHEAD OF THE COLD FRONT. GFS HAS SHOWED
STEADY TREND IN BACKING OFF QPF INTO WESTERN TIER. USED A BLEND OF
MORE CONSISTENT ECMWF AND THE DRIER TRENDING GFS. RESULT WAS SOME
LOWER CHANCE POPS FOR WESTERN LK SUPERIOR/ISLE ROYALE ON NOSE OF
H85-H7 MOISTURE ADVECTION. AS SFC LOW SPINS OVER NORTHERN ONTARIO
THE COLD FRONT WILL SLOWLY SINK NORTH TO SOUTH ACROSS LK SUPERIOR
ON THURSDAY NIGHT. BEST CHANCE FOR SHRA/ISOLD TSRA WILL BE OVR LK
SUPERIOR DUE TO H85 TEMP ADVECTION/WEAK LOW-LEVEL JET AND SOME
LOW-LEVEL FRONTAL CONVERGENCE. TEMPS WILL BE ON THE MILD SIDE
AGAIN WITH SOUTH WINDS/WARM AIR ADVECTION AHEAD OF FRONT. COLD
FRONT WORKS ACROSS UPR MICHIGAN ON FRIDAY...SO WILL KEEP WITH
SOME LOWER CHANCE POPS. COOLING BEGINS ON FRIDAY...ESPECIALLY NEAR
LK SUPERIOR. INLAND...TEMPS MAY END UP ONLY A COUPLE DEGREES COOLER
THAN THURSDAY.
STRONG DRYING BEHIND FRONT FOR FRIDAY NIGHT AND SATURDAY. JUST SOME
SCT CU SHOULD DEVELOP DURING PEAK HEATING ON SATURDAY. H85 TEMPS
ONLY UP TO +6C WITH STRONGER ONSHORE FLOW WILL LEAD TO A COOL DAY
BY AUGUST STANDARDS WITH READINGS IN THE UPPER 50S/NEAR 60 ALONG LK
SUPERIOR AND MAYBE REACHING 70 DEGREES IN THE FAR SOUTH CENTRAL NEAR
MNM. 60S ELSEWHERE...WHICH IS AT LEAST 10 DEGREES BLO NORMAL.
NOT MUCH IN WAY OF CHANGES TO REST OF CONSENSUS GRIDS FOR EXTENDED.
SLIGHT CHANCE POPS FOR SUNDAY...THOUGH THESE ARE BIASED BY A LATEST
GFS WHICH TRENDED MUCH WETTER FOR PARTS OF CWA COMPARED TO PREVIOUS
RUNS. ECMWF INDICATES SMALL CHANCES OF INSTABILITY SHRA/TSRA AS
ANOTHER STRONGER WAVE OR TWO /CURRENTLY WITHIN THE LARGER TROUGH FM
ALASKA TO THE NORTH POLE/ DROPS ACROSS UPPER LAKES. POCKET OF STEEPER
MID-LEVEL LAPSE RATES WOULD JUSTIFY AT LEAST A MENTION OF TSRA DURING
PEAK HEATING OF SUNDAY AFTN LINGERING INTO SUN EVENING. SIMILAR SETUP
FOR MONDAY THOUGH BY THAT TIME BETTER FORCING IS SLIDING EAST AND
SOUTH OF LK SUPERIOR REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1151 AM EDT TUE AUG 6 2013
SLIGHTLY DRIER AIR ACROSS NE MN THIS MORNING HAS HAD A DIFFICULT
TIME MOVING INTO UPPER MI. EVEN WITH ABUNDANT LOW LEVEL
MOISTURE...AND AN ADDITIONAL PUSH OUT OF WI ON S-SW WINDS...CEILINGS
HAVE BEEN ABLE TO SLOWLY RISE INTO MVFR CATEGORY THANKS IN PART TO
BETTER MIXING /DAYTIME HEATING/. VFR CONDITIONS WILL BE POSSIBLE
THIS AFTERNOON AHEAD OF A COLD FRONT NEARING FROM MN...WITH
DETERIORATING CONDITIONS AGAIN BY THE MID-LATE EVENING HOURS. THERE
IS A POTENTIAL FOR A BROKEN LINE OF POP UP SHOWERS AND THUNDERSTORMS
OVER MAINLY CENTRAL AND E UPPER MI THIS AFTERNOON. WILL KEEP MENTION
OF VCSH AT SAW...WITH THE POTENTIAL OF ADDING TS/CB IF ANYTHING
LOOKS MORE CERTAIN. COLD FRONT WILL MOVE INTO UPPER MI
TONIGHT...BRINGING A PERIOD OF SHRA/TS AND A RETURN TO MVFR AND
POSSIBLY IFR CONDITIONS. ONCE FRONT PASSES...UPSLOPE FLOW AT
KIWD/KCMX AND TO A LESSER EXTENT SAW WILL RESULT IN LIFR CONDITIONS
WHICH WILL LINGER THROUGH THE MID MORNING HOURS BEFORE QUICKLY
CLEARING DURING THE MID-LATE MORNING HOURS W TO E.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 548 AM EDT TUE AUG 6 2013
LIGHT WINDS THROUGH MUCH OF TONIGHT THEN WINDS WILL KICK UP AS COLD
FRONT CROSSES LK SUPERIOR LATE TONIGHT THROUGH WEDNESDAY MORNING. NW
WINDS BEHIND COLD FRONT MAY REACH 20-25 KTS IN GUSTS. SHOWERS AND
STORMS LIKELY WITH THE FRONTAL PASSAGE. SHIP REPORTS INDICATE FOG
HAS FORMED OVERNIGHT WITH ARRIVAL OF MOIST AIRMASS. EXPECT THE FOG
TO CONTINUE UNTIL WEDNESDAY AFTERNOON WHEN DRIER AIR SCOURS OUT THE
FOG. WINDS DIMINISH TO LESS THAN 20 KTS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT WITH HIGH PRESSURE OVERHEAD. STRONGER W-NW WINDS
POSSIBLE FRIDAY AND FRIDAY NIGHT AS ANOTHER COLD FRONT CROSSES
LAKE SUPERIOR FROM NORTH TO SOUTH. GUSTS COULD REACH OVER 25 KTS.
WINDS DIMINISH TO LESS THAN 20 KTS FOR REST OF WEEKEND WITH WEAKER
PRESSURE GRADIENT BY THAT TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...KF
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
740 AM EDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 548 AM EDT TUE AUG 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN UNUSUALLY DEEP VORTEX
FOR EARLY AUG CENTERED JUST S OF HUDSON BAY ALONG THE
MANITOBA/ONTARIO BORDER. ACROSS THE UPPER LAKES...FLOW HAS BECOME
MORE WESTERLY OVER THE LAST DAY OR TWO IN RESPONSE TO THE
DEEPENING/EXPANDING VORTEX THAT HAS BEEN DRIFTING S. SEVERAL
SHORTWAVES ARE EVIDENT UPSTREAM WITH 2 MORE NOTABLE WAVES OVER ERN
MT/SRN SASKATCHEWAN AND OVER ERN ALBERTA. THESE 2 WAVES WILL POWER A
COLD FRONT ACROSS UPPER MI TONIGHT AND WEDNESDAY MORNING. CLOSER TO
HOME...ISOLD/SCT SHRA (EVEN ISOLD TSRA AT TIMES) HAVE BEEN OCCURRING
OVER THE LAST SEVERAL HRS OVER WRN UPPER MI/ADJACENT LAKE SUPERIOR.
THESE SHRA ARE JUST AHEAD OF A 700MB TROF AND SURGE OF MIDLEVEL
DRYING PER BY LATEST RUC.
FOCUS EARLY THIS MORNING WILL BE ON THE ISOLD/SCT SHRA OVER THE W.
AS AFOREMENTIONED 700MB TROF CONTINUES TO PUSH E...WILL PROBABLY
CONTINUE TO SEE SOME SHRA SPREAD E INTO CNTRL UPPER MI OVER THE NEXT
SEVERAL HRS. LATEST SPC MESOANALYSIS SHOWS MUCAPE AROUND 250J/KG...
SO THERE MIGHT BE AN OCNL LIGHTNING STRIKE THOUGH THERE HAS NOT BEEN
ANY CG STRIKES FOR THE LAST COUPLE OF HRS. AS THE TROF CONTINUES
EASTWARD...IT WILL COINCIDE WITH THE HEATING CYCLE AND SHOULD AID
SHRA/TSRA DEVELOPMENT OVER THE ERN PART OF THE FCST AREA LATE THIS
MORNING/EARLY THIS AFTN...ESPECIALLY INLAND FROM LAKE MICHIGAN. SOME
HIGH RES GUIDANCE (NAM NEST AND RUC13) INDICATE LAKE BREEZE WILL
DEVELOP OFF LAKE SUPERIOR OVER THE E...BUT WILL MAKE LIMITED INLAND
PROGRESS. IF SO...CONVERGENCE ZONE WILL BE A GOOD FOCAL POINT FOR
CONVECTION. TO THE W ACROSS THE W HALF OF UPPER MI...THE SAME HIGH
RES GUIDANCE POINTS TO A MORE ACTIVE INLAND PUSH OF LAKE SUPERIOR
LAKE BREEZE. IN THE FLOW UPSTREAM...THERE ARE PROBABLY SOME SUBTLE
SHORTWAVES PRESENT GIVEN THE SCT CLUSTERS OF SHRA/TSRA THAT WERE
PRESENT EARLIER IN THE NIGHT ACROSS THE NRN PLAINS. WITH EXPECTATION
OF LOW CLOUDS CLEARING OUT/TRANSITIONING TO CU FIELD...DAYTIME
HEATING WILL LIKELY BE SUFFICIENT TO RAISE MLCAPE TO 500J/KG OR SO
PER NAM/GFS. LAKE BREEZE AND ANY SUBTLE SHORTWAVES SHOULD THEN
SUPPORT SCT SHRA/TSRA DEVELOPMENT. WITH DEEP LAYER SHEAR AROUND
35KT...SOME ORGANIZED/STRONGER STORMS ARE POSSIBLE. IF CAPE ENDS UP
HIGHER THAN CURRENTLY EXPECTED...THERE MIGHT BE AN ISOLD SVR STORM
OR TWO.
TONIGHT...THE STRONGER SHORTWAVES WELL UPSTREAM WILL PUSH A COLD
FRONT INTO UPPER MI. AS HAS BEEN THE CASE FOR THE LAST SEVERAL
DAYS...MODELS CONTINUE TO POINT TOWARD A GOOD POTENTIAL OF SHRA/TSRA
SPREADING ACROSS THE FCST AREA. WITH RATHER VIGOROUS DEEP LAYER
FORCING...STRONG MOISTURE TRANSPORT AND SHARP LOW LEVEL TROF
SHIFTING E...WILL RETAIN LIKELY POPS SPREADING E ACROSS THE AREA
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 548 AM EDT TUE AUG 6 2013
AMPLIFIED UPPER AIR PATTERN PERSISTS THROUGH THE UPCOMING WEEKEND
AND LIKELY INTO NEXT WEEK AS WELL. MEAN TROUGHING DOMINATES MUCH OF
EASTERN CANADA ACROSS THE GREAT LAKES. PRIMARY RESULT OF THIS
PATTERN WILL BE CONTINUATION OF COOLER THAN NORMAL TEMPERATURES
THROUGH AT LEAST MID AUGUST ACROSS UPPER GREAT LAKES REGION. TO
START OUT ON WEDNESDAY...MAIN FEATURES ALOFT ARE CLOSED OFF UPPER
LOW CENTERED ALONG MANITOBA AND NORTHERN ONTARIO BORDER...SHARP WEST
TO EAST RIDGE OVER FAR NORTHERN CANADA AND A DOUBLE BARRELED TROUGH
EXTENDING FROM THE NORTH POLE SOUTHWEST ACROSS ALASKA AND TO THE
NORTHERN PORTIONS OF PACIFIC OCEAN. NOT A WHOLE LOT OF CHANGE WRT
LOCATIONS OF SAID FEATURES THROUGH THE LONG TERM. ONLY THING THAT
DOES CHANGE IS UPPER LOW OVER ONTARIO SLIDES ACROSS QUEBEC THIS
WEEKEND AS STRONGER JET ENERGY BECOMES PLACED OUT AHEAD OF THE
TROUGH...KEEPING IT MORE PROGRESSIVE. MAIN CHANCE OF RAIN IN THIS
PATTERN WILL BE RIGHT OFF THE BAT ON WEDNESDAY MORNING OVER EAST
HALF OF CWA AS COLD FRONT MOVES THROUGH REGION. ADDITIONAL CHANCES
OF RAIN POSSIBLE THURSDAY NIGHT INTO FRIDAY AS SECONDARY LOW PRESSURE
SYSTEM AND COLD FRONT CROSS THE AREA. GENERALLY LOOKS QUIET THROUGH
THE WEEKEND...BUT COOL. NEXT CHANCE OF RAIN PROBABLY ARRIVES LATER
SUNDAY NIGHT INTO MONDAY AS SHORTWAVES DROP ACROSS AREA IN NW FLOW
ALOFT.
COLD FRONT SHOULD BE OVER CNTRL UPR MICHIGAN TO START THE DAY ON
WEDNESDAY...QUICKLY HEADING EAST TO AROUND ERY BTWN 15Z-18Z. NAM
STILL ON THE FAST SIDE...WHILE ECMWF IS SLOWEST. COMPROMISE SOLN
WITH FRONT IS THE GFS/GEM-REGIONAL AS WELL AS NCEP WRF-ARW/NMM.
MAJORITY OF WIDESPREAD SHRA/TSRA WILL BE ALONG AND AHEAD OF FRONT
IN WARM AIR ADVECTION REGIME. GOING FCST LOOKS PRETTY GOOD.
CHANGES TO POPS ON WEDNESDAY WITH FROPA PRETTY MINIMAL. KEPT
LIKELY POPS OVR FAR EAST THROUGH 15Z...THEN TRIMMED BACK QUICKLY
WITH ARRIVAL OF STRONG MID-LEVEL DRYING AND AS PRIMARY H85 MOISTURE
ADVECTION IS EAST OF CWA. SOUNDINGS INDICATE LINGERING LOW-LEVEL
MOISTURE BEHIND COLD FRONT THAT COULD LEAD TO BRIEF PERIOD OF LGT
RAIN/DRIZZLE IN THE MORNING FOR AREAS NEAR LK SUPERIOR.
EVENTUALLY...BLYR BECOMING MIXED ALONG WITH NEGATIVE SFC-H85 THETA-E
ADVECTION WILL SHUT DOWN ANY LINGERING PRECIP BY MIDDAY. HAVE NO
POPS AFTER 18Z WHICH WAS A BIT OF A CHANGE COMPARED TO PREVIOUS
FCST. BKN CU/SC DECK MAY REMAIN LONGER THAN THIS...BUT EVEN THAT
SHOULD TEND TO MIX OUT TO PARTLY CLOUDY SKIES BY MID-LATE AFTN.
TEMPS TRICKY WITH FROPA AS 925-850MB TEMPS JUST AHEAD OF FRONT ARE
PRETTY WARM. FIGURING OUT HOW THE WARM AIR BALANCES BTWN COOLING
FROM CLOUDS/PRECIP IS MAIN HURDLE. WILL GO FOR MAX TEMPS TOPPING OUT
IN THE LOW 70S...WARMEST SOUTH CENTRAL. TEMPS ALONG LK SUPERIOR
COULD RISE EARLY ON...BUT THEN FALL BACK IN THE AFTN WITH INCREASING
ONSHORE FLOW. SHOULD BE ESPECIALLY NOTABLE NEAR MQT-P53. FOG THAT IS
DEVELOPING ACROSS LK SUPERIOR CURRENTLY MAY GET SHOVED ONSHORE TOO
FOR A WHILE.
SFC HIGH RIDGES IN FROM CANADIAN PRAIRIE PROVINCES WEDNESDAY NIGHT
INTO THURSDAY AHEAD OF NEXT COLD FRONT. H85 WINDS STAY ONSHORE ALL
NIGHT...BUT LOWEST LEVEL WINDS THROUGH 900MB BECOME LESS
SO...ALLOWING POTENTIAL FOR TYPICAL COOL SPOTS INLAND FROM THE GREAT
LAKES TO SEE TEMPS FALL INTO THE LOWER 40S. LIGHT GRADIENT WINDS ON
THURSDAY ALLOWS IN LIGHT LAKE BREEZES ALONG BOTH SUPERIOR AND
MICHIGAN. AWAY FM LOCAL COOLING THOUGH...TEMPS SHOULD BOUNCE BACK
INTO AT LEAST THE LOWER 70S MOST AREAS GIVEN H85 TEMPS WARMER THAN
+10C. THICKENING MID CLOUDS /H6-H5/ FOR WEST HALF BY AFTN AS WARM
AIR ADVECTION DEVELOPS AHEAD OF THE COLD FRONT. GFS HAS SHOWED
STEADY TREND IN BACKING OFF QPF INTO WESTERN TIER. USED A BLEND OF
MORE CONSISTENT ECMWF AND THE DRIER TRENDING GFS. RESULT WAS SOME
LOWER CHANCE POPS FOR WESTERN LK SUPERIOR/ISLE ROYALE ON NOSE OF
H85-H7 MOISTURE ADVECTION. AS SFC LOW SPINS OVER NORTHERN ONTARIO
THE COLD FRONT WILL SLOWLY SINK NORTH TO SOUTH ACROSS LK SUPERIOR
ON THURSDAY NIGHT. BEST CHANCE FOR SHRA/ISOLD TSRA WILL BE OVR LK
SUPERIOR DUE TO H85 TEMP ADVECTION/WEAK LOW-LEVEL JET AND SOME
LOW-LEVEL FRONTAL CONVERGENCE. TEMPS WILL BE ON THE MILD SIDE
AGAIN WITH SOUTH WINDS/WARM AIR ADVECTION AHEAD OF FRONT. COLD
FRONT WORKS ACROSS UPR MICHIGAN ON FRIDAY...SO WILL KEEP WITH
SOME LOWER CHANCE POPS. COOLING BEGINS ON FRIDAY...ESPECIALLY NEAR
LK SUPERIOR. INLAND...TEMPS MAY END UP ONLY A COUPLE DEGREES COOLER
THAN THURSDAY.
STRONG DRYING BEHIND FRONT FOR FRIDAY NIGHT AND SATURDAY. JUST SOME
SCT CU SHOULD DEVELOP DURING PEAK HEATING ON SATURDAY. H85 TEMPS
ONLY UP TO +6C WITH STRONGER ONSHORE FLOW WILL LEAD TO A COOL DAY
BY AUGUST STANDARDS WITH READINGS IN THE UPPER 50S/NEAR 60 ALONG LK
SUPERIOR AND MAYBE REACHING 70 DEGREES IN THE FAR SOUTH CENTRAL NEAR
MNM. 60S ELSEWHERE...WHICH IS AT LEAST 10 DEGREES BLO NORMAL.
NOT MUCH IN WAY OF CHANGES TO REST OF CONSENSUS GRIDS FOR EXTENDED.
SLIGHT CHANCE POPS FOR SUNDAY...THOUGH THESE ARE BIASED BY A LATEST
GFS WHICH TRENDED MUCH WETTER FOR PARTS OF CWA COMPARED TO PREVIOUS
RUNS. ECMWF INDICATES SMALL CHANCES OF INSTABILITY SHRA/TSRA AS
ANOTHER STRONGER WAVE OR TWO /CURRENTLY WITHIN THE LARGER TROUGH FM
ALASKA TO THE NORTH POLE/ DROPS ACROSS UPPER LAKES. POCKET OF STEEPER
MID-LEVEL LAPSE RATES WOULD JUSTIFY AT LEAST A MENTION OF TSRA DURING
PEAK HEATING OF SUNDAY AFTN LINGERING INTO SUN EVENING. SIMILAR SETUP
FOR MONDAY THOUGH BY THAT TIME BETTER FORCING IS SLIDING EAST AND
SOUTH OF LK SUPERIOR REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 739 AM EDT TUE AUG 6 2013
ABUNDANT LOW-LEVEL MOISTURE HAS RESULTED IN LIFR CONDITIONS AT
KIWD/KCMX/KSAW EARLY THIS MORNING. DAYTIME HEATING WILL WORK TO
RAISE/SCATTER OUT THE STRATUS AND DISSIPATE FOG. EXPECT ALL
TERMINALS TO BE VFR EARLY THIS AFTN...IF NOT SOONER. AS INSTABILITY
BUILDS THIS AFTN...ISOLD/SCT SHRA/TSRA SHOULD DEVELOP OVER PARTS OF
UPPER MI. KSAW PROBABLY HAS THE BEST CHC OF SEEING SOME PCPN AS LAKE
BREEZE WILL HELP FOCUS SHRA ACTIVITY IN CNTRL UPPER MI. FOR NOW...
INCLUDED VCSH IN THE AFTN. COLD FRONT WILL MOVE INTO UPPER MI
TONIGHT...BRINGING A PERIOD OF SHRA/TSRA AND A RETURN TO MVFR AND
POSSIBLY IFR CONDITIONS. ONCE FRONT PASSES...UPSLOPE FLOW AT
KIWD/KCMX WILL RESULT IN LIFR CONDITIONS REDEVELOPING AT THOSE
TERMINALS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 548 AM EDT TUE AUG 6 2013
LIGHT WINDS THROUGH MUCH OF TONIGHT THEN WINDS WILL KICK UP AS COLD
FRONT CROSSES LK SUPERIOR LATE TONIGHT THROUGH WEDNESDAY MORNING. NW
WINDS BEHIND COLD FRONT MAY REACH 20-25 KTS IN GUSTS. SHOWERS AND
STORMS LIKELY WITH THE FRONTAL PASSAGE. SHIP REPORTS INDICATE FOG
HAS FORMED OVERNIGHT WITH ARRIVAL OF MOIST AIRMASS. EXPECT THE FOG
TO CONTINUE UNTIL WEDNESDAY AFTERNOON WHEN DRIER AIR SCOURS OUT THE
FOG. WINDS DIMINISH TO LESS THAN 20 KTS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT WITH HIGH PRESSURE OVERHEAD. STRONGER W-NW WINDS
POSSIBLE FRIDAY AND FRIDAY NIGHT AS ANOTHER COLD FRONT CROSSES
LAKE SUPERIOR FROM NORTH TO SOUTH. GUSTS COULD REACH OVER 25 KTS.
WINDS DIMINISH TO LESS THAN 20 KTS FOR REST OF WEEKEND WITH WEAKER
PRESSURE GRADIENT BY THAT TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
548 AM EDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 548 AM EDT TUE AUG 6 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN UNUSUALLY DEEP VORTEX
FOR EARLY AUG CENTERED JUST S OF HUDSON BAY ALONG THE
MANITOBA/ONTARIO BORDER. ACROSS THE UPPER LAKES...FLOW HAS BECOME
MORE WESTERLY OVER THE LAST DAY OR TWO IN RESPONSE TO THE
DEEPENING/EXPANDING VORTEX THAT HAS BEEN DRIFTING S. SEVERAL
SHORTWAVES ARE EVIDENT UPSTREAM WITH 2 MORE NOTABLE WAVES OVER ERN
MT/SRN SASKATCHEWAN AND OVER ERN ALBERTA. THESE 2 WAVES WILL POWER A
COLD FRONT ACROSS UPPER MI TONIGHT AND WEDNESDAY MORNING. CLOSER TO
HOME...ISOLD/SCT SHRA (EVEN ISOLD TSRA AT TIMES) HAVE BEEN OCCURRING
OVER THE LAST SEVERAL HRS OVER WRN UPPER MI/ADJACENT LAKE SUPERIOR.
THESE SHRA ARE JUST AHEAD OF A 700MB TROF AND SURGE OF MIDLEVEL
DRYING PER BY LATEST RUC.
FOCUS EARLY THIS MORNING WILL BE ON THE ISOLD/SCT SHRA OVER THE W.
AS AFOREMENTIONED 700MB TROF CONTINUES TO PUSH E...WILL PROBABLY
CONTINUE TO SEE SOME SHRA SPREAD E INTO CNTRL UPPER MI OVER THE NEXT
SEVERAL HRS. LATEST SPC MESOANALYSIS SHOWS MUCAPE AROUND 250J/KG...
SO THERE MIGHT BE AN OCNL LIGHTNING STRIKE THOUGH THERE HAS NOT BEEN
ANY CG STRIKES FOR THE LAST COUPLE OF HRS. AS THE TROF CONTINUES
EASTWARD...IT WILL COINCIDE WITH THE HEATING CYCLE AND SHOULD AID
SHRA/TSRA DEVELOPMENT OVER THE ERN PART OF THE FCST AREA LATE THIS
MORNING/EARLY THIS AFTN...ESPECIALLY INLAND FROM LAKE MICHIGAN. SOME
HIGH RES GUIDANCE (NAM NEST AND RUC13) INDICATE LAKE BREEZE WILL
DEVELOP OFF LAKE SUPERIOR OVER THE E...BUT WILL MAKE LIMITED INLAND
PROGRESS. IF SO...CONVERGENCE ZONE WILL BE A GOOD FOCAL POINT FOR
CONVECTION. TO THE W ACROSS THE W HALF OF UPPER MI...THE SAME HIGH
RES GUIDANCE POINTS TO A MORE ACTIVE INLAND PUSH OF LAKE SUPERIOR
LAKE BREEZE. IN THE FLOW UPSTREAM...THERE ARE PROBABLY SOME SUBTLE
SHORTWAVES PRESENT GIVEN THE SCT CLUSTERS OF SHRA/TSRA THAT WERE
PRESENT EARLIER IN THE NIGHT ACROSS THE NRN PLAINS. WITH EXPECTATION
OF LOW CLOUDS CLEARING OUT/TRANSITIONING TO CU FIELD...DAYTIME
HEATING WILL LIKELY BE SUFFICIENT TO RAISE MLCAPE TO 500J/KG OR SO
PER NAM/GFS. LAKE BREEZE AND ANY SUBTLE SHORTWAVES SHOULD THEN
SUPPORT SCT SHRA/TSRA DEVELOPMENT. WITH DEEP LAYER SHEAR AROUND
35KT...SOME ORGANIZED/STRONGER STORMS ARE POSSIBLE. IF CAPE ENDS UP
HIGHER THAN CURRENTLY EXPECTED...THERE MIGHT BE AN ISOLD SVR STORM
OR TWO.
TONIGHT...THE STRONGER SHORTWAVES WELL UPSTREAM WILL PUSH A COLD
FRONT INTO UPPER MI. AS HAS BEEN THE CASE FOR THE LAST SEVERAL
DAYS...MODELS CONTINUE TO POINT TOWARD A GOOD POTENTIAL OF SHRA/TSRA
SPREADING ACROSS THE FCST AREA. WITH RATHER VIGOROUS DEEP LAYER
FORCING...STRONG MOISTURE TRANSPORT AND SHARP LOW LEVEL TROF
SHIFTING E...WILL RETAIN LIKELY POPS SPREADING E ACROSS THE AREA
TONIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 548 AM EDT TUE AUG 6 2013
AMPLIFIED UPPER AIR PATTERN PERSISTS THROUGH THE UPCOMING WEEKEND
AND LIKELY INTO NEXT WEEK AS WELL. MEAN TROUGHING DOMINATES MUCH OF
EASTERN CANADA ACROSS THE GREAT LAKES. PRIMARY RESULT OF THIS
PATTERN WILL BE CONTINUATION OF COOLER THAN NORMAL TEMPERATURES
THROUGH AT LEAST MID AUGUST ACROSS UPPER GREAT LAKES REGION. TO
START OUT ON WEDNESDAY...MAIN FEATURES ALOFT ARE CLOSED OFF UPPER
LOW CENTERED ALONG MANITOBA AND NORTHERN ONTARIO BORDER...SHARP WEST
TO EAST RIDGE OVER FAR NORTHERN CANADA AND A DOUBLE BARRELED TROUGH
EXTENDING FROM THE NORTH POLE SOUTHWEST ACROSS ALASKA AND TO THE
NORTHERN PORTIONS OF PACIFIC OCEAN. NOT A WHOLE LOT OF CHANGE WRT
LOCATIONS OF SAID FEATURES THROUGH THE LONG TERM. ONLY THING THAT
DOES CHANGE IS UPPER LOW OVER ONTARIO SLIDES ACROSS QUEBEC THIS
WEEKEND AS STRONGER JET ENERGY BECOMES PLACED OUT AHEAD OF THE
TROUGH...KEEPING IT MORE PROGRESSIVE. MAIN CHANCE OF RAIN IN THIS
PATTERN WILL BE RIGHT OFF THE BAT ON WEDNESDAY MORNING OVER EAST
HALF OF CWA AS COLD FRONT MOVES THROUGH REGION. ADDITIONAL CHANCES
OF RAIN POSSIBLE THURSDAY NIGHT INTO FRIDAY AS SECONDARY LOW PRESSURE
SYSTEM AND COLD FRONT CROSS THE AREA. GENERALLY LOOKS QUIET THROUGH
THE WEEKEND...BUT COOL. NEXT CHANCE OF RAIN PROBABLY ARRIVES LATER
SUNDAY NIGHT INTO MONDAY AS SHORTWAVES DROP ACROSS AREA IN NW FLOW
ALOFT.
COLD FRONT SHOULD BE OVER CNTRL UPR MICHIGAN TO START THE DAY ON
WEDNESDAY...QUICKLY HEADING EAST TO AROUND ERY BTWN 15Z-18Z. NAM
STILL ON THE FAST SIDE...WHILE ECMWF IS SLOWEST. COMPROMISE SOLN
WITH FRONT IS THE GFS/GEM-REGIONAL AS WELL AS NCEP WRF-ARW/NMM.
MAJORITY OF WIDESPREAD SHRA/TSRA WILL BE ALONG AND AHEAD OF FRONT
IN WARM AIR ADVECTION REGIME. GOING FCST LOOKS PRETTY GOOD.
CHANGES TO POPS ON WEDNESDAY WITH FROPA PRETTY MINIMAL. KEPT
LIKELY POPS OVR FAR EAST THROUGH 15Z...THEN TRIMMED BACK QUICKLY
WITH ARRIVAL OF STRONG MID-LEVEL DRYING AND AS PRIMARY H85 MOISTURE
ADVECTION IS EAST OF CWA. SOUNDINGS INDICATE LINGERING LOW-LEVEL
MOISTURE BEHIND COLD FRONT THAT COULD LEAD TO BRIEF PERIOD OF LGT
RAIN/DRIZZLE IN THE MORNING FOR AREAS NEAR LK SUPERIOR.
EVENTUALLY...BLYR BECOMING MIXED ALONG WITH NEGATIVE SFC-H85 THETA-E
ADVECTION WILL SHUT DOWN ANY LINGERING PRECIP BY MIDDAY. HAVE NO
POPS AFTER 18Z WHICH WAS A BIT OF A CHANGE COMPARED TO PREVIOUS
FCST. BKN CU/SC DECK MAY REMAIN LONGER THAN THIS...BUT EVEN THAT
SHOULD TEND TO MIX OUT TO PARTLY CLOUDY SKIES BY MID-LATE AFTN.
TEMPS TRICKY WITH FROPA AS 925-850MB TEMPS JUST AHEAD OF FRONT ARE
PRETTY WARM. FIGURING OUT HOW THE WARM AIR BALANCES BTWN COOLING
FROM CLOUDS/PRECIP IS MAIN HURDLE. WILL GO FOR MAX TEMPS TOPPING OUT
IN THE LOW 70S...WARMEST SOUTH CENTRAL. TEMPS ALONG LK SUPERIOR
COULD RISE EARLY ON...BUT THEN FALL BACK IN THE AFTN WITH INCREASING
ONSHORE FLOW. SHOULD BE ESPECIALLY NOTABLE NEAR MQT-P53. FOG THAT IS
DEVELOPING ACROSS LK SUPERIOR CURRENTLY MAY GET SHOVED ONSHORE TOO
FOR A WHILE.
SFC HIGH RIDGES IN FROM CANADIAN PRAIRIE PROVINCES WEDNESDAY NIGHT
INTO THURSDAY AHEAD OF NEXT COLD FRONT. H85 WINDS STAY ONSHORE ALL
NIGHT...BUT LOWEST LEVEL WINDS THROUGH 900MB BECOME LESS
SO...ALLOWING POTENTIAL FOR TYPICAL COOL SPOTS INLAND FROM THE GREAT
LAKES TO SEE TEMPS FALL INTO THE LOWER 40S. LIGHT GRADIENT WINDS ON
THURSDAY ALLOWS IN LIGHT LAKE BREEZES ALONG BOTH SUPERIOR AND
MICHIGAN. AWAY FM LOCAL COOLING THOUGH...TEMPS SHOULD BOUNCE BACK
INTO AT LEAST THE LOWER 70S MOST AREAS GIVEN H85 TEMPS WARMER THAN
+10C. THICKENING MID CLOUDS /H6-H5/ FOR WEST HALF BY AFTN AS WARM
AIR ADVECTION DEVELOPS AHEAD OF THE COLD FRONT. GFS HAS SHOWED
STEADY TREND IN BACKING OFF QPF INTO WESTERN TIER. USED A BLEND OF
MORE CONSISTENT ECMWF AND THE DRIER TRENDING GFS. RESULT WAS SOME
LOWER CHANCE POPS FOR WESTERN LK SUPERIOR/ISLE ROYALE ON NOSE OF
H85-H7 MOISTURE ADVECTION. AS SFC LOW SPINS OVER NORTHERN ONTARIO
THE COLD FRONT WILL SLOWLY SINK NORTH TO SOUTH ACROSS LK SUPERIOR
ON THURSDAY NIGHT. BEST CHANCE FOR SHRA/ISOLD TSRA WILL BE OVR LK
SUPERIOR DUE TO H85 TEMP ADVECTION/WEAK LOW-LEVEL JET AND SOME
LOW-LEVEL FRONTAL CONVERGENCE. TEMPS WILL BE ON THE MILD SIDE
AGAIN WITH SOUTH WINDS/WARM AIR ADVECTION AHEAD OF FRONT. COLD
FRONT WORKS ACROSS UPR MICHIGAN ON FRIDAY...SO WILL KEEP WITH
SOME LOWER CHANCE POPS. COOLING BEGINS ON FRIDAY...ESPECIALLY NEAR
LK SUPERIOR. INLAND...TEMPS MAY END UP ONLY A COUPLE DEGREES COOLER
THAN THURSDAY.
STRONG DRYING BEHIND FRONT FOR FRIDAY NIGHT AND SATURDAY. JUST SOME
SCT CU SHOULD DEVELOP DURING PEAK HEATING ON SATURDAY. H85 TEMPS
ONLY UP TO +6C WITH STRONGER ONSHORE FLOW WILL LEAD TO A COOL DAY
BY AUGUST STANDARDS WITH READINGS IN THE UPPER 50S/NEAR 60 ALONG LK
SUPERIOR AND MAYBE REACHING 70 DEGREES IN THE FAR SOUTH CENTRAL NEAR
MNM. 60S ELSEWHERE...WHICH IS AT LEAST 10 DEGREES BLO NORMAL.
NOT MUCH IN WAY OF CHANGES TO REST OF CONSENSUS GRIDS FOR EXTENDED.
SLIGHT CHANCE POPS FOR SUNDAY...THOUGH THESE ARE BIASED BY A LATEST
GFS WHICH TRENDED MUCH WETTER FOR PARTS OF CWA COMPARED TO PREVIOUS
RUNS. ECMWF INDICATES SMALL CHANCES OF INSTABILITY SHRA/TSRA AS
ANOTHER STRONGER WAVE OR TWO /CURRENTLY WITHIN THE LARGER TROUGH FM
ALASKA TO THE NORTH POLE/ DROPS ACROSS UPPER LAKES. POCKET OF STEEPER
MID-LEVEL LAPSE RATES WOULD JUSTIFY AT LEAST A MENTION OF TSRA DURING
PEAK HEATING OF SUNDAY AFTN LINGERING INTO SUN EVENING. SIMILAR SETUP
FOR MONDAY THOUGH BY THAT TIME BETTER FORCING IS SLIDING EAST AND
SOUTH OF LK SUPERIOR REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 131 AM EDT TUE AUG 6 2013
ABUNDANT LOW LEVEL MOISTURE WILL REMAIN IN PLACE OVERNIGHT AS WEAK
SRLY FLOW CONTINUES. EXPECT IFR/LIFR CIGS AT SAW/CMX TO PERSIST AND
ONLY GRADUALLY IMPROVE TODAY AS WRLY FLOW BEHIND A SFC TROUGH BRINGS
IN DRIER AIR. CIGS ARE EXPECTED TO ALSO DROP INTO THE IFR RANGE AT
IWD PER GUIDANCE AND MDL LOW LEVEL MOISTURE FCST...ALTHOUGH
CONFIDENCE IS LOWER GIVEN MAINLY VFR/MVFR UPSTREAM CONDITIONS OVER NW
WI. ANY LEFTOVER LOWER CIGS SHOULD LIFT TO MVFR BY MID/LATE MORNING
AND TO VFR IN THE AFTERNOON. CIGS/VIS IS EXPECTED TO DROP AGAIN BY
EVENING AS SHOWERS MOVE IN AHEAD OF THE NEXT TROUGH. SOME THUNDER
MAY ALSO BE POSSIBLE BUT PROB/CONFIDENCE WAS LOW ENOUGH TO LEAVE OUT
MENTION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 548 AM EDT TUE AUG 6 2013
LIGHT WINDS THROUGH MUCH OF TONIGHT THEN WINDS WILL KICK UP AS COLD
FRONT CROSSES LK SUPERIOR LATE TONIGHT THROUGH WEDNESDAY MORNING. NW
WINDS BEHIND COLD FRONT MAY REACH 20-25 KTS IN GUSTS. SHOWERS AND
STORMS LIKELY WITH THE FRONTAL PASSAGE. SHIP REPORTS INDICATE FOG
HAS FORMED OVERNIGHT WITH ARRIVAL OF MOIST AIRMASS. EXPECT THE FOG
TO CONTINUE UNTIL WEDNESDAY AFTERNOON WHEN DRIER AIR SCOURS OUT THE
FOG. WINDS DIMINISH TO LESS THAN 20 KTS WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT WITH HIGH PRESSURE OVERHEAD. STRONGER W-NW WINDS
POSSIBLE FRIDAY AND FRIDAY NIGHT AS ANOTHER COLD FRONT CROSSES
LAKE SUPERIOR FROM NORTH TO SOUTH. GUSTS COULD REACH OVER 25 KTS.
WINDS DIMINISH TO LESS THAN 20 KTS FOR REST OF WEEKEND WITH WEAKER
PRESSURE GRADIENT BY THAT TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT TUE AUG 6 2013
.SYNOPSIS...
ISSUED AT 330 AM EDT TUE AUG 6 2013
IT WILL BE WARMER AND MORE HUMID TODAY WITH A FEW SHOWERS AND
THUNDERSTORMS. A COLD FRONT WILL BRING A BETTER CHANCE FOR SHOWERS
AND STORMS VERY LATE TONIGHT THROUGH WEDNESDAY. FAIR WEATHER WITH
SEASONABLE TEMPERATURES WILL RETURN LATE THIS WEEK.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY AFTERNOON)
ISSUED AT 330 AM EDT TUE AUG 6 2013
SOUTHERLY FLOW WILL RESULT IN WARMER AND MORE HUMID WEATHER TODAY
WITH SUFFICIENT INSTABILITY FOR SCATTERED SHOWERS AND PERHAPS A FEW
STORMS TO DEVELOP THROUGH THE DAY. MAINTAINED ONLY LOW POPS SINCE
THERE IS A LACK OF A FOCUSING MECHANISM FOR CONVECTIVE INITIATION TO
OCCUR.
THE COLD FRONT WILL BRING A MUCH BETTER CHANCE FOR RAIN AND STORMS
VERY LATE TONIGHT THROUGH WEDNESDAY. THE BEST CHANCE FOR STRONGER
STORMS SHOULD COME WEDNESDAY AFTERNOON BUT THIS WILL BE LARGELY
CONTINGENT ON EXTENT OF CLOUD COVER AND INSTABILITY. MOISTURE IS
SUFFICIENT BUT SEVERE WX SEEMS UNLIKELY GIVEN LACK OF STRONGER
INSTABILITY.
DRY WX WITH SEASONABLE TEMPS WILL RETURN BEHIND THAT FRONT WEDNESDAY
NIGHT THROUGH THURSDAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 330 AM EDT TUE AUG 6 2013
IN GENERAL THE LONG TERM PERIOD LOOKS RELATIVELY QUIET WITH
TEMPERATURES CONTINUING TO AVERAGE A FEW DEGREES BELOW NORMAL.
PERSISTENT TROUGHING OVER EASTERN CANADA LOOKS TO STAY PUT WHICH
KEEPS A PREDOMINATELY NORTHWEST FLOW ALOFT IN TACT OVER THE GREAT
LAKES REGION.
AS THE CLOSED UPPER LOW CURRENTLY NEAR WESTERN HUDSON BAY DROPS
SSW... OUR FLOW ALOFT ACTUALLY GOES TEMPORARILY SOUTHWESTERLY ON
THURSDAY NIGHT INTO FRIDAY. AN UPPER LEVEL JET STREAK OF 100-120 KTS
PROGGED ON THE SOUTHEAST SIDE OF THE UPPER LOW ACROSS LAKE SUPERIOR
CREATES RIGHT ENTRANCE REGION DYNAMICS OVER SRN LWR MI. THIS MAY
HELP CREATE A RAIN SHOWER POTENTIAL ON THE NORTH SIDE OF THE STALLED
FRONTAL BOUNDARY TO OUR SOUTH. FOR THIS REASON WILL CARRY A SLIGHT
CHANCE OF RAIN SHOWERS THURSDAY NIGHT AND FRIDAY.
THE ONTARIO UPPER LOW LIFTS NORTHEAST INTO QUEBEC OVER THE
WEEKEND... SO WOULD NOT EXPECT MUCH OF A COLD AIR INTRUSION FROM THE
NORTH. RATHER... THE ZONAL FLOW ALOFT AND RIDGING AT THE SURFACE
SHOULD LEAD TO PLEASANT TEMPERATURES/HUMIDITIES OVER THE COMING
WEEKEND ALONG WITH DRY WEATHER. WILL REMAIN OPTIMISTIC WITH THE SKY
COVER FORECAST... BUT SUSPECT THAT INTERVALS OF THICKER MID/HIGH
CLOUDINESS WITHIN THE FAST ZONAL FLOW ALOFT MAY IMPACT THE AREA FROM
TIME TO TIME.
A SHORTWAVE DROPPING DOWN FROM THE NORTHWEST ON SUNDAY NIGHT AND
MONDAY COULD PRODUCE A FEW SHOWERS... BUT TIMING OF THIS FEATURE IS
TOUGH THAT FAR OUT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1152 PM EDT MON AUG 5 2013
AS I WAS THINKING AT 6 PM... THE LOW CLOUDS WILL COME IN FROM
WISCONSIN OVERNIGHT BRINGING IFR CIGS ACROSS THE AREA THAT WILL
NOT LIFT UNTIL LATE MORNING OR EARLY AFTERNOON TO TUESDAY.
THE REAL QUESTION IS WILL THERE BE SHOWERS OVERNIGHT... ENOUGH TO
LOWER THE VISIBILITIES THAT IS? GIVEN THE WATER VAPOR IMAGE LOOPS
SHOWING SO MUCH MID-LEVEL DRY AIR.... AND SEEING RAP AND NAM 00Z
MODEL RUN SOUNDINGS SHOWING SO MUCH DRY AIR ABOVE 700 MB THROUGH
THE NIGHT... EVEN SOUTH OF INTERSTATE 94... IT IS HARD TO IMAGE
ANYTHING TO SIGNIFICANT DEVELOPING. WHAT EVER DOES HAPPEN.. ARE
MORE LIKELY SOUTH OF INTERSTATE 96... SINCE THAT AREA IS CLOSER
THE TO BETTER MOISTURE AND BETTER LOW LEVEL INFLOW. I FEATURES
SHOWERS OVER THE SOUTHERN TAF SITES ONLY ON THE 06Z TAF SET.
&&
.MARINE...
ISSUED AT 330 AM EDT TUE AUG 6 2013
WAVE HEIGHTS MAINLY IN THE 1 TO 3 FOOT RANGE ARE EXPECTED TODAY IN
WARM AIR ADVECTION SOUTHERLY FLOW. WINDS WILL STRENGTHEN A BIT IN
ADVANCE OF THE COLD FRONT TONIGHT THAT SHOULD BUILD WAVES UP TO
AROUND 2 TO 4 FEET NORTH OF MUSKEGON. AFTER FROPA WEDNESDAY WAVES
WILL INCREASE IN NORTHERLY FLOW COOL AIR ADVECTION AND SMALL CRAFT
ADVISORIES AND BEACH HAZARDS STATEMENTS MAY BE NEEDED.
&&
.HYDROLOGY...
ISSUED AT 330 AM EDT TUE AUG 6 2013
ANY RAINFALL TODAY WILL BE RATHER LIGHT BUT SOME STEADIER RAIN AND
STORMS SHOULD ARRIVE LATE TONIGHT THROUGH WEDNESDAY WITH BASIN AVG
QPF AMOUNTS OF AT LEAST A QUARTER TO HALF INCH POSSIBLE WITH LOCALLY
HIGHER AMOUNTS. HOWEVER GIVEN ANTECEDENT LOW RIVER FLOWS WE DO NOT
EXPECT TO HAVE ANY MAJOR HYDRO ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...MEADE
AVIATION...WDM
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
204 PM CDT Tue Aug 6 2013
.SHORT TERM...(Today and Tonight)
ISSUED AT 349 AM CDT TUE AUG 6 2013
Very serious flooding situation unfolding across the area this
morning. A band of thunderstorms producing heavy rainfall has set
of up from roughly the Lake of the Ozark area southeastward
through portions of Laclede/Pulaski counties and into the northern
half of Texas county. Radar estimates vary a bit, but given
rainfall rate observations from the past several nights, as much
as 8" of rain has fallen in spots.
This band of rainfall will be the primary concern this morning. A
decaying line of storms entering from the west has produced a
large swath of moderate rain. Rainfall amounts are more modest
with a general half inch to one inch of rainfall over a longer
duration, with embedded pockets of up to two inches of rainfall.
The biggest concern for this morning is that band of torrential
rainfall from central Missouri into the eastern Ozarks and the
extreme flooding risk. Looking at the HRRR and other short range
models, this band of rainfall will not move much through day
break. With hourly rainfall rates between one and two inches, a
bad situation will only get worse.
Rain will gradually end from west to east during the mid to late
morning hours. Like yesterday some clearing is expected and a warm
and humid afternoon is in store. Instability will quickly increase
during the afternoon and additional isolated to widely scattered
thunderstorms will be possible across the entire area. There will
be a limited risk for severe with this activity, with hail to the
size of quarters and localized damaging wind gusts. This activity
will likely persist into the evening in a widely scattered
fashion. Then attention will turn to a complex of thunderstorms
develop to our north/northwest. This will approach the area from
the northwest overnight tonight. In addition, much like the past
few nights, will need to watch for low level jet interaction with
any lingering boundaries. This activity will be possible just
about anywhere across the outlook area. The air mass remains
extremely moist, and flash flooding will once again be a major
concern.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 349 AM CDT TUE AUG 6 2013
The forecast for midweek into early next week remains complex and
concerning. Northwest flow aloft will keep our region in the
atmospheric battleground, and multiple rounds of showers and
thunderstorms remain possible. There is moderate confidence in
another round of heavy rainfall Wednesday night into Thursday. As
a result, the Flash Flood Watch will be extended into Thursday
morning.
The medium range models do offer a glimmer of hope for the weekend
and the pattern briefly deamplifies and the atmospheric
battleground shifts just to the west. Tough to get to confident in
this solution given the persistent upper level pattern that has
been in place. One can certainly hope, though.
The bottom line is that more rounds of rain will be possible.
Temperatures will be at or below average (depending on cloud
coverage and rain).
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
ISSUED AT 156 PM CDT TUE AUG 6 2013
For the KSGF/KJLN/KBBG tafs...a front over IA/NEB will drop south
into the region tonight. Scattered showers are ongoing near KJLN
and KSGF and will watch trends, but better chances for showers and
thunderstorms would appear to be tonight toward 06Z. Will keep
tafs mainly in the vfr cat but no doubt there will be mvfr or ifr
possibilities in heavier rain showers. There is potential for a
more prolonged period of lower clouds late in the taf period near
and just north of the sfc boundary, but there is not a lot of
confidence in the boundary position by that time.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through Thursday morning FOR MOZ055>058-
066>071-077>083-088>098-101>106.
KS...FLASH FLOOD WATCH through Thursday morning FOR KSZ073-097-101.
&&
$$
SHORT TERM...Gagan
LONG TERM...Gagan
AVIATION...DSA
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1221 PM CDT Tue Aug 6 2013
.SHORT TERM...(Today through Wednesday)
Issued at 307 AM CDT TUE AUG 6 2013
Large MCS continues to interact with synoptic boundary arcing from
west central Missouri southeast through the Ozarks. Based on 00Z
soundings, convective outflow boundary should be more than sufficient
forcing to easily overturn the entire warm sector air mass as well as
the region through about 50 miles north. This sharp delineation has
been well handled by the HRRR and NSSL WRF runs, and takes the
northern extent of the thunderstorms to roughly the MO river from
Kansas City metro eastward. Thunderstorm cloud tops have continued
to be in the -75 to -80C range with prolific lightning counts. This
would suggest that despite the rich boundary layer moisture, rainfall
efficiency is not as high as it could be. Nonetheless, 1-2"/hr rates
are almost certain in the heavier cells, and there may be some
tendency for slower storm movement/propagation where the outflow
boundary becomes W-E oriented along the nrn edge of the convection.
80-100% POPs generally carried along and south of the MO river
(slightly more NW- SE oriented) with a rapid decrease further north.
Given the short term setup, while we definitely need the rain around
Kansas City, mesoscale influences suggest this is also the most
likely region for flooding through the next 3-4 hours if conceptual
evolution materializes.
Elsewhere, areas of light fog are expected along the periphery of the
MCS cloud shield where subsidence will work in concert with more
efficient boundary layer cooling and high antecedent moisture
content.
MCS (if not MCC designated) should gradually exit the CWA to the
southeast this morning as the low level jet veers, with convective
debris cirrus lingering through the morning. Like yesterday, most
aggressive warming will occur during the afternoon hours. Given the
very stagnant air mass in place, will introduce haze into the
forecast, coupling with otherwise very sultry conditions expected as
dewpoints climb into the middle 70s. Other than a rogue pulse
thunderstorm or two during the afternoon along a residual boundary,
expect the region to be fairly quiet between 15-00Z.
By evening, a disturbance currently producing active deep convection
over SW South Dakota will reach far NW MO. Despite model variances,
there appears to be an overall suggestion that at least scattered
thunderstorms will develop and/or move into NW MO early this evening,
possibly growing upscale overnight as this activity moves southeast.
SPC highlights the area with a broad slight risk overnight for wind
damage potential. Given some modest increase/linearity to the
700-500mb flow, certainly cannot rule out some storm organization.
This system should also clear the region by late morning, leaving a
hazy, warm and very humid day again on Wednesday.
.LONG TERM...(Thursday through Monday)
Issued at 307 AM CDT TUE AUG 6 2013
Remnant energy lifting northward out of the Baja California
Peninsula and into the Central Plains on Thursday will provide a
reasonable chance for fairly widespread rains across the lower
Missouri river valley. By Thursday morning ECMWF/GFS both suggest
increased troughing over the central Rockies, allowing for southwest
flow to move into the Plains. Strong warm advection ahead of this
wave of energy may be strong enough to force baroclinic zone which
has been stuck to the south of the CWA northward during the day. As
this upper wave ejects eastward Thursday night into Friday, fairly
pronounced mid-level lift provided by PVA and an enhanced upper jet
streak should keep PoPs high overnight as several rounds of showers
and thunderstorms will be possible.
High pressure is expected to sink southward into the central US on
Friday, leading to dry conditions for the first half of the weekend.
Increased troughing off the West Coast combined with fairly
progressive zonal flow over the Nation`s midsection will lead to
lower forecast confidence by early next week. Several waves of
energy may again eject eastward out of this trough, but timing of
these features remains too problematic to target any one time period
for higher PoPs.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1216 PM CDT TUE AUG 6 2013
Challenging precipitation forecast for the next 24 hours. Cannot
rule out a brief shower this afternoon at terminals, but with no
expected reduction in flight category have left out of TAF at this
time. Otherwise anticipate overnight showers/thunderstorms in the
vicinity or over terminals during the 05-13Z window, but specific
impacts and timing still highly uncertain. Wind shift expected
Wednesday morning following a cold frontal passage to prevailing
northeasterly winds.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Blair
AREA FORECAST DISCUSSION...UPDATED
NWS SPRINGFIELD MO
640 AM CDT Tue Aug 6 2013
...SERIOUS FLASH FLOODING SITUATION CONTINUES ACROSS PORTIONS OF
TEXAS AND PULASKI COUNTIES...
.MESOSCALE DISCUSSION...
Issued AT 639 AM CDT TUE AUG 6 2013
Low level jet continues to veer and moisture transport remains
focused from central Missouri through the eastern Ozarks and into
south central Missouri. Some good news is that there has been a
weakening trend to this activity, especially in the areas hardest
hit in Pulaski and Texas counties. Could still see an additional
half inch of rain or so, but the heaviest rain rates have come to
an end.
Latest radar trends suggest an orderly west to east end to the
precipitation and will update timing shortly. Forecast for the
afternoon looks good at this point. Should see at least partial
clearing with a warm/humid afternoon on tap. Isolated to widely
scattered pulse thunderstorm redevelopment remains plausible this
afternoon.
&&
.SHORT TERM...(Today and Tonight)
ISSUED AT 349 AM CDT TUE AUG 6 2013
Very serious flooding situation unfolding across the area this
morning. A band of thunderstorms producing heavy rainfall has set
of up from roughly the Lake of the Ozark area southeastward
through portions of Laclede/Pulaski counties and into the northern
half of Texas county. Radar estimates vary a bit, but given
rainfall rate observations from the past several nights, as much
as 8" of rain has fallen in spots.
This band of rainfall will be the primary concern this morning. A
decaying line of storms entering from the west has produced a
large swath of moderate rain. Rainfall amounts are more modest
with a general half inch to one inch of rainfall over a longer
duration, with embedded pockets of up to two inches of rainfall.
The biggest concern for this morning is that band of torrential
rainfall from central Missouri into the eastern Ozarks and the
extreme flooding risk. Looking at the HRRR and other short range
models, this band of rainfall will not move much through day
break. With hourly rainfall rates between one and two inches, a
bad situation will only get worse.
Rain will gradually end from west to east during the mid to late
morning hours. Like yesterday some clearing is expected and a warm
and humid afternoon is in store. Instability will quickly increase
during the afternoon and additional isolated to widely scattered
thunderstorms will be possible across the entire area. There will
be a limited risk for severe with this activity, with hail to the
size of quarters and localized damaging wind gusts. This activity
will likely persist into the evening in a widely scattered
fashion. Then attention will turn to a complex of thunderstorms
develop to our north/northwest. This will approach the area from
the northwest overnight tonight. In addition, much like the past
few nights, will need to watch for low level jet interaction with
any lingering boundaries. This activity will be possible just
about anywhere across the outlook area. The airmass remains
extremely moist, and flash flooding will once again be a major
concern.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 349 AM CDT TUE AUG 6 2013
The forecast for midweek into early next week remains complex and
concerning. Northwest flow aloft will keep our region in the
atmospheric battleground, and multiple rounds of showers and
thunderstorms remain possible. There is moderate confidence in
another round of heavy rainfall Wednesday night into Thursday. As
a result, the Flash Flood Watch will be extended into Thursday
morning.
The medium range models do offer a glimmer of hope for the weekend
and the pattern briefly deamplifies and the atmospheric
battleground shifts just to the west. Tough to get to confident in
this solution given the persistent upper level pattern that has
been in place. One can certainly hope, though.
The bottom line is that more rounds of rain will be possible.
Temperatures will be at or below average (depending on cloud
coverage and rain).
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
ISSUED AT 639 AM CDT TUE AUG 6 2013
Rainfall is exiting from west to east out of the JLN/SGF/BBG
aerodromes. VFR conditions are expected today with gradual
clearing of mid/high deck expected. Will need to monitor for
isolated to widely scattered thunderstorm development during the
mid/late afternoon hours. Confidence is not high enough to include
at this point. Will also be monitoring for another round of
thunderstorms tonight.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through Thursday morning FOR MOZ055>058-
066>071-077>083-088>098-101>106.
KS...FLASH FLOOD WATCH through Thursday morning FOR KSZ073-097-101.
&&
$$
MESOSCALE...Gagan
SHORT TERM...Gagan
LONG TERM...Gagan
AVIATION...Gagan
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
631 AM CDT TUE AUG 6 2013
.SHORT TERM...(Today through Wednesday)
Issued at 307 AM CDT TUE AUG 6 2013
Large MCS continues to interact with synoptic boundary arcing from
west central Missouri southeast through the Ozarks. Based on 00Z
soundings, convective outflow boundary should be more than sufficient
forcing to easily overturn the entire warm sector air mass as well as
the region through about 50 miles north. This sharp delineation has
been well handled by the HRRR and NSSL WRF runs, and takes the
northern extent of the thunderstorms to roughly the MO river from
Kansas City metro eastward. Thunderstorm cloud tops have continued
to be in the -75 to -80C range with prolific lightning counts. This
would suggest that despite the rich boundary layer moisture, rainfall
efficiency is not as high as it could be. Nonetheless, 1-2"/hr rates
are almost certain in the heavier cells, and there may be some
tendency for slower storm movement/propagation where the outflow
boundary becomes W-E oriented along the nrn edge of the convection.
80-100% POPs generally carried along and south of the MO river
(slightly more NW- SE oriented) with a rapid decrease further north.
Given the short term setup, while we definitely need the rain around
Kansas City, mesoscale influences suggest this is also the most
likely region for flooding through the next 3-4 hours if conceptual
evolution materializes.
Elsewhere, areas of light fog are expected along the periphery of the
MCS cloud shield where subsidence will work in concert with more
efficient boundary layer cooling and high antecedent moisture
content.
MCS (if not MCC designated) should gradually exit the CWA to the
southeast this morning as the low level jet veers, with convective
debris cirrus lingering through the morning. Like yesterday, most
aggressive warming will occur during the afternoon hours. Given the
very stagnant air mass in place, will introduce haze into the
forecast, coupling with otherwise very sultry conditions expected as
dewpoints climb into the middle 70s. Other than a rogue pulse
thunderstorm or two during the afternoon along a residual boundary,
expect the region to be fairly quiet between 15-00Z.
By evening, a disturbance currently producing active deep convection
over SW South Dakota will reach far NW MO. Despite model variances,
there appears to be an overall suggestion that at least scattered
thunderstorms will develop and/or move into NW MO early this evening,
possibly growing upscale overnight as this activity moves southeast.
SPC highlights the area with a broad slight risk overnight for wind
damage potential. Given some modest increase/linearity to the
700-500mb flow, certainly cannot rule out some storm organization.
This system should also clear the region by late morning, leaving a
hazy, warm and very humid day again on Wednesday.
.LONG TERM...(Thursday through Monday)
Issued at 307 AM CDT TUE AUG 6 2013
Remnant energy lifting northward out of the Baja California
Peninsula and into the Central Plains on Thursday will provide a
reasonable chance for fairly widespread rains across the lower
Missouri river valley. By Thursday morning ECMWF/GFS both suggest
increased troughing over the central Rockies, allowing for southwest
flow to move into the Plains. Strong warm advection ahead of this
wave of energy may be strong enough to force baroclinic zone which
has been stuck to the south of the CWA northward during the day. As
this upper wave ejects eastward Thursday night into Friday, fairly
pronounced mid-level lift provided by PVA and an enhanced upper jet
streak should keep PoPs high overnight as several rounds of showers
and thunderstorms will be possible.
High pressure is expected to sink southward into the central US on
Friday, leading to dry conditions for the first half of the weekend.
Increased troughing off the West Coast combined with fairly
progressive zonal flow over the Nation`s midsection will lead to
lower forecast confidence by early next week. Several waves of
energy may again eject eastward out of this trough, but timing of
these features remains too problematic to target any one time period
for higher PoPs.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 628 AM CDT TUE AUG 6 2013
Convective complex has exited east of the STJ-MCI-MKC terminals
early this morning, however foggy conditions persist to the north
and east with IFR/local LIFR expected to improve aft 13Z.
For today, high clouds should burn off by mid morning. However, with
stagnant airmass in place, haze aloft will continue to become an
increase concern. VFR conditions to continue otherwise with lgt/vrb
winds becoming southeast at 8-10 knots.
Models very consistent with developing a complex of strong to severe
thunderstorms across IA/NE later this afternoon (possibly an
extension of ongoing activity near Omaha), and pushing it quickly
southward this evening. Best guess is 03-05Z across the terminals,
with strong wind gusts and torrential rainfall potentially impacting
late evening arrival rates.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Bookbinder
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
349 AM CDT Tue Aug 6 2013
...SERIOUS FLASH FLOODING SITUATION UNFOLDING ACROSS PORTIONS OF
TEXAS AND PULASKI COUNTIES...
.SHORT TERM...(Today and Tonight)
ISSUED AT 349 AM CDT TUE AUG 6 2013
Very serious flooding situation unfolding across the area this
morning. A band of thunderstorms producing heavy rainfall has set
of up from roughly the Lake of the Ozark area southeastward
through portions of Laclede/Pulaski counties and into the northern
half of Texas county. Radar estimates vary a bit, but given
rainfall rate observations from the past several nights, as much
as 8" of rain has fallen in spots.
This band of rainfall will be the primary concern this morning. A
decaying line of storms entering from the west has produced a
large swath of moderate rain. Rainfall amounts are more modest
with a general half inch to one inch of rainfall over a longer
duration, with embedded pockets of up to two inches of rainfall.
The biggest concern for this morning is that band of torrential
rainfall from central Missouri into the eastern Ozarks and the
extreme flooding risk. Looking at the HRRR and other short range
models, this band of rainfall will not move much through day
break. With hourly rainfall rates between one and two inches, a
bad situation will only get worse.
Rain will gradually end from west to east during the mid to late
morning hours. Like yesterday some clearing is expected and a warm
and humid afternoon is in store. Instability will quickly increase
during the afternoon and additional isolated to widely scattered
thunderstorms will be possible across the entire area. There will
be a limited risk for severe with this activity, with hail to the
size of quarters and localized damaging wind gusts. This activity
will likely persist into the evening in a widely scattered
fashion. Then attention will turn to a complex of thunderstorms
develop to our north/northwest. This will approach the area from
the northwest overnight tonight. In addition, much like the past
few nights, will need to watch for low level jet interaction with
any lingering boundaries. This activity will be possible just
about anywhere across the outlook area. The airmass remains
extremely moist, and flash flooding will once again be a major
concern.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 349 AM CDT TUE AUG 6 2013
The forecast for midweek into early next week remains complex and
concerning. Northwest flow aloft will keep our region in the
atmospheric battleground, and multiple rounds of showers and
thunderstorms remain possible. There is moderate confidence in
another round of heavy rainfall Wednesday night into Thursday. As
a result, the Flash Flood Watch will be extended into Thursday
morning.
The medium range models do offer a glimmer of hope for the weekend
and the pattern briefly deamplifies and the atmospheric
battleground shifts just to the west. Tough to get to confident in
this solution given the persistent upper level pattern that has
been in place. One can certainly hope, though.
The bottom line is that more rounds of rain will be possible.
Temperatures will be at or below average (depending on cloud
coverage and rain).
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
ISSUED AT 815 PM CDT MON AUG 5 2013
Pilots can expect additional storms to move into the region
overnight bringing areas of MVFR conditions and the potential of
strong thunderstorm winds. IFR conditions will be possible in the
heavier rainfall. Improving flight conditions will return by
Tuesday afternoon.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH through Thursday morning FOR MOZ055>058-
066>071-077>083-088>098-101>106.
KS...FLASH FLOOD WATCH through Thursday morning FOR KSZ073-097-101.
&&
$$
SHORT TERM...Gagan
LONG TERM...Gagan
AVIATION...Foster
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
311 AM CDT Tue Aug 6 2013
.SHORT TERM...(Today through Wednesday)
Issued at 307 AM CDT TUE AUG 6 2013
Large MCS continues to interact with synoptic boundary arcing from
west central Missouri southeast through the Ozarks. Based on 00Z
soundings, convective outflow boundary should be more than sufficient
forcing to easily overturn the entire warm sector air mass as well as
the region through about 50 miles north. This sharp delineation has
been well handled by the HRRR and NSSL WRF runs, and takes the
northern extent of the thunderstorms to roughly the MO river from
Kansas City metro eastward. Thunderstorm cloud tops have continued
to be in the -75 to -80C range with prolific lightning counts. This
would suggest that despite the rich boundary layer moisture, rainfall
efficiency is not as high as it could be. Nonetheless, 1-2"/hr rates
are almost certain in the heavier cells, and there may be some
tendency for slower storm movement/propagation where the outflow
boundary becomes W-E oriented along the nrn edge of the convection.
80-100% POPs generally carried along and south of the MO river
(slightly more NW- SE oriented) with a rapid decrease further north.
Given the short term setup, while we definitely need the rain around
Kansas City, mesoscale influences suggest this is also the most
likely region for flooding through the next 3-4 hours if conceptual
evolution materializes.
Elsewhere, areas of light fog are expected along the periphery of the
MCS cloud shield where subsidence will work in concert with more
efficient boundary layer cooling and high antecedent moisture
content.
MCS (if not MCC designated) should gradually exit the CWA to the
southeast this morning as the low level jet veers, with convective
debris cirrus lingering through the morning. Like yesterday, most
aggressive warming will occur during the afternoon hours. Given the
very stagnant air mass in place, will introduce haze into the
forecast, coupling with otherwise very sultry conditions expected as
dewpoints climb into the middle 70s. Other than a rogue pulse
thunderstorm or two during the afternoon along a residual boundary,
expect the region to be fairly quiet between 15-00Z.
By evening, a disturbance currently producing active deep convection
over SW South Dakota will reach far NW MO. Despite model variances,
there appears to be an overall suggestion that at least scattered
thunderstorms will develop and/or move into NW MO early this evening,
possibly growing upscale overnight as this activity moves southeast.
SPC highlights the area with a broad slight risk overnight for wind
damage potential. Given some modest increase/linearity to the
700-500mb flow, certainly cannot rule out some storm organization.
This system should also clear the region by late morning, leaving a
hazy, warm and very humid day again on Wednesday.
.LONG TERM...(Thursday through Monday)
Issued at 307 AM CDT TUE AUG 6 2013
Remnant energy lifting northward out of the Baja California
Peninsula and into the Central Plains on Thursday will provide a
reasonable chance for fairly widespread rains across the lower
Missouri river valley. By Thursday morning ECMWF/GFS both suggest
increased troughing over the central Rockies, allowing for southwest
flow to move into the Plains. Strong warm advection ahead of this
wave of energy may be strong enough to force baroclinic zone which
has been stuck to the south of the CWA northward during the day. As
this upper wave ejects eastward Thursday night into Friday, fairly
pronounced mid-level lift provided by PVA and an enhanced upper jet
streak should keep PoPs high overnight as several rounds of showers
and thunderstorms will be possible.
High pressure is expected to sink southward into the central US on
Friday, leading to dry conditions for the first half of the weekend.
Increased troughing off the West Coast combined with fairly
progressive zonal flow over the Nation`s midsection will lead to
lower forecast confidence by early next week. Several waves of
energy may again eject eastward out of this trough, but timing of
these features remains too problematic to target any one time period
for higher PoPs.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1045 PM CDT MON AUG 5 2013
Cluster of storms across southeast Kansas will continue to move east
southeast through the overnight hours. Bulk of the activity should
pass south of Kansas City, so only include VCTS in the KC terminals
for the early morning hours. Otherwise, thoughts are that ceilings
will stay in the VFR range unless a thunderstorm directly effects a
terminal, which will have to be handled with an amendment.
Otherwise, expect winds to back around to the south by the early
afternoon hours.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Cutter
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1132 PM CDT MON AUG 5 2013
.UPDATE...
ISSUED AT 844 PM CDT MON AUG 5 2013
THUNDERSTORMS HAVE STAYED SOUTHWEST OF THE CWA THIS EVENING...
THOUGH DO EXPECT ADDITIONAL STORMS TO DEVELOP FROM EASTERN KANSAS
INTO SOUTHEAST MISSOURI OVERNIGHT. THESE STORMS WILL DEVELOP IN A
BAND OF LOW LEVEL MOISTURE CONVERGENCE ON THE BROAD NOSE OF A LOW
LEVEL JET. LATEST RUNS OF THE HRRR SUGGESTS THAT NORTHERN AND
EASTERN EDGE OF THUNDERSTORMS WILL MOVE INTO CENTRAL AND SOUTHEAST
MISSOURI TOWARD SUNRISE...WITH BEST COVERAGE ACROSS SOUTHEAST
MISSOURI INTO SOUTHERN ILLINOIS BETWEEN 10-15Z. HAVE ADJUSTED RAIN
CHANCES TO GO ALONG WITH THIS IDEA. OTHERWISE...GOING FORECAST
LOOKS GOOD AND ONLY MADE MINOR TWEAKS TO TEMPERATURE AND CLOUD
COVER TO MATCH WITH GOING TRENDS.
BRITT
&&
.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 333 PM CDT MON AUG 5 2013
FRONTAL BOUNDARY TO THE SOUTH WILL SLOWLY RETREAT AND MOVE NORTHWARD
OVERNIGHT TONIGHT. ISOLATED TO SCATERRED CONVECTION HAS DEVELOPED
ALONG IT OVER THE PAST COUPLE OF HOURS ACROSS PORTIONS OF SW
MISSOURI. THINKING THAT THIS CONVECTION SHOULD WEAKEN AND DIE OUT
THIS EVENING WITH LOSS OF DAYLIGHT HEATING. TIED HIGHEST POPS
TONIGHT TO PORTIONS OF SOUTH CENTRAL AND SOUTHEAST MISSOURI WHICH
WILL BE IN CLOSER PROXIMITY TO AFOREMENTIONED FRONT. DID LOWER
POPS A BIT FROM PREVIOUS FORECAST AS CONVERGENCE ALONG FRONT IS
RATHER WEAK AND LOW LEVEL FORCING IS PROGGED TO BE NOT NEARLY AS
STRONG OR FOCUSED TONIGHT AS PREVIOUS FEW NIGHTS. ALONG AND NORTH
OF BOUNDARY LOW STRATUS...AND POSSIBLY FOG...TO AFFECT MUCH OF THE
REGION WHICH WILL HELP KEEP LOW TEMPERATURES UP IN THE UPPER 60S
TO LOW 70S. BOOSTED LOWS A DEGREE OR TWO ABOVE WARMER MAV
GUIDANCE DUE TO EXPECTED LOW CLOUD COVER OVERNIGHT TONIGHT.
GOSSELIN
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 333 PM CDT MON AUG 5 2013
WITH WAA/ISENTROPIC ASCENT STILL OVER OUR AREA TUESDAY MORNING
COUPLED WITH A FEW VORTICITY MAXIMA RIDING OVER A RIDGE TO OUR SW...
THE SHOWERS AND THUNDERSTORMS THAT DEVELOPS OVERNIGHT SHOULD
CONTINUE TO PROPAGATE INTO OUR S COUNTIES DURING THE
MORNING...WITH LIKELY POPS AS FAR N AS A COLUMBIA TO SPARTA LINE.
ELSEWHERE...WILL MAINTAIN CHANCE OF POPS THROUGHOUT THE DAY...AS
TONGUE OF WAA PERSISTS OVER OUR AREA COUPLED WITH A FEW WEAK
SHORTWAVES WITHIN THE GENERAL FLOW. BY TUESDAY NIGHT...EXPECTING
AN UPTICK IN CONVECTIVE ACTIVITY OVER THE N 2/3 OF THE CWA AS WAA
INTENSIFIES EVEN MORE AHEAD OF APPRROACHING SHORTWAVE AND
ASSOCIATED COLD FRONT.
ON WEDNESDAY THE COLD FRONT IS EXPECTED TO SWEEP ACROSS THE AREA.
SOME MODELS SUGGEST THAT THE IMPACTS OF THE OVERNIGHT CONVECTION MAY
INHIBIT ADDITIONAL DEVELOPMENT OF CONVECTION ALONG THE FRONT DURING
THE DAY. HOWEVER...HAVE NOT MADE ANY MAJOR CHANGES TO CURRENT POPS ATTM.
12Z GFS REBOUNDS THE FRONTAL BOUNDARY AS A WARM FRONT ACROSS
OUR AREA LATE WEDNESDAY INTO THURSDAY MORNING IN RESPONSE TO A
DEEPENING SHORTWAVE TO THE WEST...WHILE MANY OF THE OTHER 12Z
SOLUTIONS ALLOW THE FRONTAL BOUNDARY TO SETTLE INTO N ARKANSAS.
WHILE THIS WILL IMPACT TEMPS...ALL SOLUTIONS POINT TO ACTIVE
BAROCLINIC ZONE REMAINING OVER S MISSOURI AND S ILLINOIS. THEREFORE
HAVE MAINTAINED LIKELY POPS OVER SOUTHERN SECTIONS OF THE CWA
THROUGH THURSDAY NIGHT WITH A CHANCE OF POPS ACROSS THE NORTH.
WITH TIME...MEDIUM RANGE SOLUTIONS DO INIDICATE THAT THE
BAROCLINIC ZONE WILL SAG SOUTH...WHICH IN TURN SHOULD ALLOW A SLOW
DECREASE IN POPS IN THE FRIDAY-SATURDAY TIME FRAME. HOWEVER...IT
APPEARS THAT TSRA THREAT WILL BE RETURNING BY THE START OF NEXT
WEEK AS LOW LEVEL WARM ADVECTION REDEVELOPS ACROSS THE REGION.
HUSTEDDE/TRUETT
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1105 PM CDT MON AUG 5 2013
RATHER COMPLEX WX SITUATION WITH ONE AREA OF MVFR CIGS MOVING SWD
OVER PORTIONS OF CENTRAL IL AND NERN MO...ANOTHER AREA OF IFR CIGS
MOVING NWD AND NEWD CURRENTLY ACROSS SRN AND SWRN IL AS WELL AS
SERN AND E CENTRAL MO. COMPLICATING MATTERS IS AREA OF TSRA
CURRENTLY OVER KS MOVING EWD WITH CI SHIELD OVER THE REGION.
UIN MAY COOL ENUF THRU THE NIGHT FOR AT LEAST MVFR FG TO DEVELOP
ALONG WITH AREA OF MVFR CIGS MOVING BACK NWD AS THE WRMFNT LIFTS
NWD TONIGHT. COU SHUD REMAIN VFR THRU MUCH OF THE NIGHT AS THICKER
CI CONTINUES TO MOVE OVER THE AREA AS TSRA COMPLEX APPROACHES.
BELIEVE THESE TSRA WILL REMAIN JUST S OF COU TERMINAL...BUT MAY
STILL SEE SPRINKLES OR A BRIEF PERIOD OF -RA. THESE TSRA ARE ALSO
EXPECTED TO REMAIN JUST S OF SUS/CPS TUES MORNING...BUT CAN NOT
RULE OUT DEVELOPMENT ALONG THE NRN FRINGES OF THE COMPLEX. UNTIL
THESE TSRA ARRIVE...BELIEVE IFR CIGS WILL REMAIN IN PLACE AS THE
WRMFNT SHUD REMAIN JUST S OF THE TERMINALS. THESE CIGS SHUD BE
SLOW TO RISE TUES.
KEPT MENTION OF VCSH TUES AFTERNOON WITH REDEVELOPMENT EXPECTED
ALONG THE FNT. BETTER CHANCES EXIST AT UIN TUES NIGHT NEAR THE END
OF THE TAF PERIOD AS A CDFNT MOVES S INTO THE REGION. WILL LEAVE
OUT FOR NOW.
SPECIFICS FOR KSTL...TSRA OVER KS WILL MOVE ESE TOWARD ERN MO
OVERNIGHT. EXPECT TSRA TO REMAIN S OF TERMINAL...BUT CAN NOT RULE
OUT DEVELOPMENT ALONG THE NRN FRINGES OF THIS COMPLEX. UNTIL
THEN...BELIEVE IFR CIGS WILL REMAIN IN PLACE AS THE WRMFNT
APPROACHES THE AREA. LOW CIGS SHUD BE SLOW TO LIFT TUES MORNING.
KEPT MENTION OF VCSH TUES AFTERNOON WHERE REDEVELOPMENT OF TSRA
ALONG THE FNT IS EXPECTED.
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
215 PM MDT TUE AUG 6 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
NORTHWESTERLY FLOW ALOFT CONTINUES THROUGH THURSDAY. WEATHER FOR
THE NORTHERN CONUS IS DOMINATED BY A LARGE UPPER LOW OVER NORTH
CENTRAL CANADA. AS THIS LOW SPINS AND MAKES SLOW PROGRESS
EASTWARD OVER THE NEXT FEW DAYS...PERIODIC SHORTWAVE DISTURBANCES IN
THE FLOW AROUND THE LOW PASS OVER THE MONTANA AREA. THESE
DISTURBANCES BRING SUPPORT FOR SHOWERS AND THUNDERSTORMS. SHOWER
ACTIVITY MOSTLY OCCURS IN THE AFTERNOONS AS DAYTIME HEATING OF THE
RELATIVELY MOIST BOUNDARY LAYER CREATES CONVECTIVE INSTABILITY
WHICH COMBINES WITH MODEST UPPER LEVEL FORCING FROM SHORTWAVE
ACTIVITY.
CURRENTLY..SOME NON-SEVERE SHOWER AND THUNDERSTORM ACTIVITY IS
EXPECTED WITH THE PASSAGE OF A SHORTWAVE TONIGHT WITH A WEAKER ONE DUE
LATE WEDNESDAY. THURSDAY AFTERNOON HAS A LOWER CHANCE OF
CONVECTIVE ACTIVITY AS THE GFS AND NAM HAVE THE CANADA LOW BY
THAT TIME FAR ENOUGH EASTWARD TO ALLOW SOME BUILDING OF HIGH
PRESSURE OVER THE ROCKIES.
FOR TONIGHT...THE HRRR MODEL SEEMS TO HAVE A REASONABLE HANDLE ON
DEVELOPMENT FOLLOWING THE LOWER RESOLUTION MODELS IN PRODUCING AN
AREA OF SHOWERS OVER THE NORTHEAST 2/3RDS OF THE CWA...WHICH DIES OUT
AROUND 9PM. STRENGTH OF CONVECTION IS EXPECTED TO BE
MODEST...THOUGH SOME THUNDERSTORMS WILL OCCUR...AS BOUNDARY LAYER
INSTABILITY IS WEAK WITH LESS THAN 1000 J/KG OF MLCAPE AT
MOST...WHICH RAPIDLY DECLINES AFTER 6PM AS THE SURFACE COOLS
DIURNALLY.
TEMPERATURES ARE EXPECTED TO BE MILD THROUGH THURSDAY DUE TO CLOUD
COVER AND LIMITED THICKNESSES IN THE SOUTHWEST QUADRANT OF THE
CANADA LOW. THERE IS ALSO A LACK OF WELL-DEFINED SURFACE FEATURES
THAT WOULD LEAD TO STRONG WINDS. CURRENT SURFACE LOW EXITING THE
DAKOTAS HAS KEPT NORTHWESTERLY SURFACE WINDS IN PLACE. THESE WINDS
WILL BECOME LIGHTER TONIGHT AND WEDNESDAY...AND THEN MORE EASTERLY
ON THURSDAY AS A THERMAL SURFACE LOW DEVELOPS OVER THE ROCKIES. MARTIN
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED PERIOD BEGINS THURSDAY NIGHT WITH HIGH PRESSURE AND A
HEAT DOME OVER THE SOUTHWESTERN DESERT...WITH AN UPPER RIDGE
EXTENDING NORTH ALL THE WAY UP INTO THE PACIFIC NORTHWEST. THE
CLOSED UPPER LEVEL CANADIAN LOW WILL BE RETREATING EAST INTO
ONTARIO...LEAVING BEHIND IN ITS WAKE ANOTHER...BUT WEAKER...TROUGH
OVER THE PRAIRIE PROVINCES. THIS PATTERN WILL MAINTAIN OUR
NORTHWEST FLOW ALOFT AND THE STATIONARY BOUNDARY ACROSS NORTHEAST
MONTANA THROUGH MOST OF THE WEEKEND. THIS FLOW WILL NOT BE
CLEAN...RESULTING IN OCCASIONAL SHORT PERIODS OF RAIN SHOWERS OR
THUNDERSTORMS. THEN AS THE RIDGE ATTEMPTS TO MOVE EAST A COUPLE OF
LOWS IN THE PAC-NW AND WESTERN CANADA SEND MOISTURE OVER THE
DIVIDE. THIS MOISTURE AND MORE DISTURBANCES WILL TEND TO KNOCK
DOWN THE RIDGE AND CONTINUE TO PRODUCE RAIN SHOWERS AND
THUNDERSTORMS INTO NEXT WEEK. GUIDANCE SUGGEST WARMING TO ABOVE
NORMAL...BUT THE PATTERN MIGHT RESIST THAT GUIDANCE TREND. FEW
SIGNIFICANT CHANGES WERE NEEDED. SCT
PREVIOUS DISCUSSION...
FORECAST THROUGH THE END OF THE WEEK WILL BE INFLUENCED BY THE
LINGERING EFFECTS OF THE STRONG HUDSON BAY LOW. UPPER RIDGE
BUILDING NORTH ALONG THE ROCKIES WILL BE THE MAIN PLAYER FOR EARLY
NEXT WEEK.
MODELS SLIPPING OUT OF AGREEMENT REGARDING THE HUDSON BAY LOW
AFTER IT DROPS INTO CENTRAL MANITOBA. ECMWF MOVES IT EAST FASTER
THEN THE GFS BUT LEAVES A PORTION BEHIND IN SASKATCHEWAN THURSDAY
NIGHT. EC CURRENTLY NOT INDICATING MUCH INFLUENCE ON THE SENSIBLE
WEATHER WITH THIS FEATURE BUT THAT COULD CHANGE. NORTHWEST FLOW
INTO EASTERN MONTANA ALONG WITH CANADIAN HIGH PUSHING INTO THE
NORTHERN PLAINS SUGGEST A SHORT PERIOD OF DRIER WEATHER BUT AS
SHORTWAVES BEGIN EJECTING OUT OF THE TROF ALONG THE WEST COAST AND
THROUGH THE NORTHERN ROCKIES RIDGE...WILL SEE A RETURN OF
THUNDERSTORM CHANCES.
AFTER A COOL START TO THE EXTENDED PERIOD WITH THE PROXIMITY OF
THE HUDSON BAY LOW...TEMPERATURES WILL WARM THROUGH THE WEEKEND
AS UPPER RIDGE PUSHES OUT INTO THE NORTHERN PLAINS. EBERT
&&
.AVIATION...
VFR.
AN UPPER LEVEL RIDGE WEST OF THE DIVIDE AND A STRONG LOW PRESSURE
SYSTEM OVER HUDSON BAY WILL MAINTAIN NORTHWEST FLOW ALOFT FOR
NORTHEAST MONTANA. THESE WEATHER SYSTEMS HAVE PLACED A STATIONARY
COLD FRONT ACROSS THE LOCAL AREA THAT WILL BE THE FOCUS OF
INTERMITTENT RAIN SHOWERS AND GENERAL THUNDERSTORMS THIS AFTERNOON
THROUGH WEDNESDAY. BRIEF PERIODS OF LESS THAN VFR CONDITIONS ARE
POSSIBLE WITH ANY THUNDERSTORM THAT DEVELOPS.
A SURFACE TROUGH ACROSS THE DAKOTAS WILL MAINTAIN NORTHERLY SURFACE
WIND THIS AFTERNOON. EXPECT WIND SPEED OF AROUND 10KT TO 20KT.
WIND WILL BECOME LIGHT AND VARIABLE TONIGHT AND INTO WEDNESDAY
AFTERNOON. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
924 AM MDT TUE AUG 6 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
AREAS IN THE SOUTHWEST PART OF THE CWA ARE MOSTLY CLEAR...SO
REDUCED CLOUD COVER AND POPS IN THAT AREA FOR THIS MORNING FOR THIS
UPDATE. THE HRRR AND OTHER MODELS HAVE PRECIPITATION DEVELOPING
AFTER 18Z OVER THE NORTHEAST 2/3RDS OF THE CWA...AND THIS APPEARS
TO BE WELL-REPRESENTED IN THE CURRENT FORECAST. VERY MARGINAL
INSTABILITY SHOULD KEEP ANY THUNDERSHOWER ACTIVITY ON THE WEAK SIDE. MARTIN
PREVIOUS DISCUSSION...
SYNOPTIC SET UP... A LARGE CLOSED COLD CORE LOW IS
CENTERED OVER NORTHERN MANITOBA AND ITS INFLUENCE SPREADS FAR BACK
ACROSS THE CANADIAN PRAIRIES AND NORTHERN US HIGH PLAINS. TO THE
SOUTH A LARGE HIGH PRESSURE HEAT DOME STRETCHES FROM THE SOUTHERN
PLAINS TO THE FOUR CORNERS INTO THE LOWER INTERMOUNTAIN WEST.
NORTHEAST MONTANA LIES IN ZONAL FLOW BETWEEN THESE TWO LARGE
FEATURES. TO THE WEST A RIDGE RUNS UP BRITISH COLUMBIA WITH A
BROAD WEAK TROUGH OFF THE COAST OF CANADA AND THE US.
TODAY THROUGH TONIGHT... THE COLD AIR ACROSS THE REGION IS
ANTICIPATED TO MOVE OFF TO THE WEST DURING THE MORNING HOURS.
WHILE THE RIDGE ACROSS THE INTERMOUNTAIN WEST IS EXPECTED TO SURGE
UP INTO THE BRITISH COLUMBIA RIDGE... RE-ROUTING SLOWLY TO
NORTHWEST FLOW AND WARMING THE AREA SLIGHTLY. A WEAK SHORTWAVE IS
ANTICIPATED TO RIDE AROUND THE MANITOBA LOW AND WILL BRIEFLY BRUSH
THE NORTHEAST CORNER OF THE CWA DURING THE AFTERNOON HOURS.
CAPE WITH THIS SYSTEM/SHORTWAVE COULD REACH UP TO 1000 J/KG DURING THE
AFTERNOON WITH WEAK SHEAR. CAPE ALSO LOOKS VERY THIN ALLOWING FOR
WEAKENING DRY AIR ENTRAINMENT EFFECTS. THIS COULD PRODUCE SOME
SMALL HAIL BUT WILL HAVE A HARD TIME BECOMING SEVERE. IN
ADDITION... CAPE LOOKS VERY MUCH SURFACE BASED. SO... AS THE SUN GOES
DOWN THUNDERSTORMS WILL RAPIDLY DIE OFF LEADING TO A FAIRLY DRY
OVERNIGHT PERIOD.
WEDNESDAY THROUGH THURSDAY... TEMPERATURES WILL BRIEFLY RISE AGAIN
WEDNESDAY. AFTER THAT... A CONFIDENCE PROBLEM ARISES WITH TWO
SOLUTIONS.,. ONE BEING THE GFS/NAM AND THE OTHER BEING THE
GEM/EC. GFS/NAM SOLUTION BRINGS A SHORTWAVE THROUGH WITH A VERY
SHARPENED COLD FRONT AROUND MIDNIGHT. THE EC/GEM SOLUTION BRINGS
THE SHORTWAVE THROUGH... BUT DELAYS THE FRONT ABOUT 12 TO 24 HOURS
LATER BY LEAVING IT VERY DIFFUSE. BOUNDARY OR NOT... CHANCES FOR
POPS SHOULD SHOOT UP A BIT THROUGH THESE PERIODS WITH THE
SHORTWAVE. THE QUESTION IS THE EXTENT TO WHICH IT SHOOTS UP BEING
DEPENDENT UPON THE FRONT. GAH
.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
FORECAST THROUGH THE END OF THE WEEK WILL BE INFLUENCED BY THE LINGERING
EFFECTS OF THE STRONG HUDSON BAY LOW. UPPER RIDGE BUILDING NORTH
ALONG THE ROCKIES WILL BE THE MAIN PLAYER FOR EARLY NEXT WEEK.
MODELS SLIPPING OUT OF AGREEMENT REGARDING THE HUDSON BAY LOW
AFTER IT DROPS INTO CENTRAL MANITOBA. ECMWF MOVES IT EAST FASTER
THEN THE GFS BUT LEAVES A PORTION BEHIND IN SASKATCHEWAN THURSDAY
NIGHT. EC CURRENTLY NOT INDICATING MUCH INFLUENCE ON THE SENSIBLE
WEATHER WITH THIS FEATURE BUT THAT COULD CHANGE. NORTHWEST FLOW
INTO EASTERN MONTANA ALONG WITH CANADIAN HIGH PUSHING INTO THE
NORTHERN PLAINS SUGGEST A SHORT PERIOD OF DRIER WEATHER BUT AS
SHORTWAVES BEGIN EJECTING OUT OF THE TROF ALONG THE WEST COAST AND
THROUGH THE NORTHERN ROCKIES RIDGE...WILL SEE A RETURN OF
THUNDERSTORM CHANCES.
AFTER A COOL START TO THE EXTENDED PERIOD WITH THE PROXIMITY OF
THE HUDSON BAY LOW...TEMPERATURES WILL WARM THROUGH THE WEEKEND AS
UPPER RIDGE PUSHES OUT INTO THE NORTHERN PLAINS. EBERT
&&
.AVIATION...
MOSTLY VFR TODAY...EXCEPT FOR MORNING LOW STRATUS IN THE MISSOURI
AND YELLOWSTONE RIVER VALLEYS AFFECTING KOLF AND KSDY WITH MVFR
CEILINGS.
AN UPPER LEVEL RIDGE WEST OF THE DIVIDE AND A STRONG LOW PRESSURE
SYSTEM OVER HUDSON BAY WILL MAINTAIN NORTHWEST FLOW ALOFT FOR
NORTHEAST MONTANA. THESE WEATHER SYSTEMS HAVE PLACED A STATIONARY
COLD FRONT ACROSS THE LOCAL AREA THAT WILL BE THE FOCUS OF
INTERMITTENT RAIN SHOWERS AND GENERAL THUNDERSTORMS THIS
AFTERNOON THROUGH WEDNESDAY. BRIEF PERIODS OF LESS THAN VFR
CONDITIONS ARE POSSIBLE WITH ANY THUNDERSTORM THAT DEVELOPS.
A SURFACE TROUGH ACROSS THE DAKOTAS WILL MAINTAIN NORTHWEST
SURFACE WIND THIS MORNING THAT WILL VEER TO THE NORTH BY
AFTERNOON. EXPECT WIND SPEED OF AROUND 10KT TO 20KT. WIND WILL
BECOME LIGHT AND VARIABLE TONIGHT AND WEDNESDAY MORNING. SCT
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1132 PM MDT MON AUG 5 2013
.AVIATION...
06Z TAF CYCLE
AN ACTIVE EVENING WINDING DOWN. HOWEVER...ISOLATED SHOWERS AND
STORMS STILL ONGOING OVER WESTERN AND NORTHERN NM. WILL CARRY AN
HOUR OR TWO TEMPO -SHRA AT KGUP...KFMN...KABQ AND KSAF. ALSO VCTS
AT KGUP AND KFMN. SHOULD BE VFR CONDITIONS THOUGH THROUGH AT LEAST
18Z TUE. NEXT CROP OF CONVECTION TUESDAY PM AND EVE MAY BE EVEN
MORE WIDESPREAD THAN TODAY AS AN UPPER LEVEL DISTURBANCE MOVES
NORTH ACROSS ERN AZ...DRAWING ADDITIONAL MOISTURE NORTH. WILL
CARRY VCTS ALL TERMINALS TUE PM EXCEPT KROW WHERE CHANCES WILL
BE LOWEST.
&&
.PREV DISCUSSION...244 PM MDT MON AUG 5 2013...
LESS ACTIVE TODAY THAN AT THIS TIME YESTERDAY. SHOWERS AND STORMS
WITH LOCALLY HVY RAIN ARE STILL DEVELOPING OVER THE NORTHERN AND
WESTERN HIGH TERRAIN AND EASTERN HIGH PLAINS. STORM MOTIONS ARE
FASTER AND MORE TO THE NORTHEAST. LAPS PARAMETERS STILL INDICATE
POTENTIAL FOR A FEW STRONG STORMS ARE FLASH FLOODING IS NOT OUT
OF THE QUESTION FOR ANY AREA. RUC GUIDANCE AGAIN SHOWS ACTIVITY
MERGING INTO THE RGV THIS VALLEY HOWEVER CONFIDENCE NOT AS HIGH
SINCE OTHER GUIDANCE MEMBERS KEEP ALL ACTIVITY FARTHER SOUTH AND
THERE IS A LESS THAN IMPRESSIVE CU FIELD OVER THE AREA ATTM. THE
INTERESTINGLY THERE IS A WELL DEFINED WAVE THAT HAS DEVELOPED IN
THE MONSOONAL PLUME HEADING NORTH INTO THE NM BOOTHEEL. FOR THIS
REASON HAVE KEPT A LARGER THAN TYPICAL AREA OF CHANCE POPS FOR
THE OVERNIGHT.
THE NEXT VERY WELL DEFINED WAVE IS POISED OVER THE BAJA REGION
AND THIS WILL MOVE NORTH THROUGH THE MONSOON PLUME TUESDAY. TOTAL
BLENDED PWAT VALUES PER CIRA IMAGERY WITH THIS WAVE ARE IN THE
2.25-2.50 RANGE. 12Z GFS INDICATES THE MAX THETA-E WAVE ASSOCIATED
WITH THIS SYSTEM WILL SLIDE OVER CENTRAL AND WESTERN NM NOW...
WHICH IS A LITTLE FARTHER EAST THAN PREVIOUS RUNS. STORM MOTIONS
WILL BE FASTER TO THE NE BUT FLASH FLOODING IS STILL A CONCERN.
THIS UPPER WAVE WILL GET CAUGHT UP IN INCREASING WESTERLY FLOW
OVER THE CENTRAL ROCKIES THEN NW FLOW OVER THE GREAT PLAINS.
A BACK DOOR FRONTAL BOUNDARY WILL BE FORCED SOUTHWARD INTO THE NE
PLAINS BEHIND THESE UPPER DYNAMICS. VERY MOIST UPSLOPE FLOW WILL
IMPACT THE SANGRES EASTWARD ACROSS THE PLAINS AND GIVEN LATEST
ROUNDS OF HEAVY RAINFALL IN THIS AREA...THE FLASH FLOOD THREAT
WILL BE QUITE HIGH. WEDNESDAY NIGHT EXPECTING TO SEE A LARGE RAIN
SHIELD SHIFTING SOUTHEAST OVER THE EAST...FOLLOWED BY A DRIER DAY
FOR THURSDAY. TEMPS WILL BE BELOW NORMAL THROUGH THE WHOLE PERIOD.
THE FRIDAY THROUGH MONDAY PERIOD LOOKS INTERESTING WITH ANOTHER
MONSOON BURST POSSIBLE DURING THIS TIME OVER CENTRAL AND WESTERN
NM. MODEL CONSISTENCY ON TIMING AND PLACEMENT IS NOT THE BEST
SO WILL KEEP VALUES JUST AT CLIMO OR BELOW FOR NOW.
GUYER
.FIRE WEATHER...
UPPER HIGH WILL REMAIN CENTERED OVER PORTIONS OF TEXAS AND THE LOWER
MISSISSIPPI VALLEY THROUGH TUESDAY. THE MONSOONAL MOISTURE PLUME
WILL REMAIN CENTERED OVER WESTERN AND CENTRAL NEW MEXICO DURING THIS
PERIOD. WETTING THUNDERSTORMS WILL BE EMBEDDED WITHIN THIS PLUME
WITH HIGHER HUMIDITY.
MODELS SHOWS A GRADUAL CHANGE IN THE MONSOON FLOW WEDNESDAY AND
THURSDAY AS A WEAK TROUGH SWINGS ACROSS THE SOUTHERN AND CENTRAL
ROCKIES. WEDNESDAY COULD BE QUITE DYNAMIC AS FAR AS AN EXPECTED
DRIER TREND ACROSS THE WEST AND WETTING THUNDERSTORMS CENTRAL AND
EASTERN AREAS. MODELS SHOW AN UPTICK IN THE UPPER FLOW SO THIS
SHOULD TRANSLATE INTO A LITTLE STRONGER SURFACE WIND VERSUS WHAT WE
HAVE HAD THE PAST SEVERAL DAYS. MIGHT BE A LITTLE LOW IN THE GRIDDED
WIND FORECAST SO WILL WATCH THE TREND IN THE MODELS. A BACK DOOR
COLD FRONT TIED TO A VIGOROUS LOW PRESSURE AREA SHOULD ADD TO THE
THUNDERSTORM FOCUS ACROSS THE NORTHEAST. IT APPEARS THAT HUMIDITY
VALUES LOWER THE MOST ACROSS THE SOUTHWEST HALF. THURSDAY LOOKS TO
BE DRIER BOTH HUMIDITY AND WETTING THUNDERSTORM WISE. WINDS ALSO
LOOK TO BE LIGHTER ON THURSDAY VERSUS WEDNESDAY.
BOTH THE ECMWF AND GFS WEATHER MODELS SHOW THE UPPER HIGH
REDEVELOPING OVER CENTRAL TEXAS ON FRIDAY. MONSOONAL MOISTURE WOULD
TRY TO FLOW BACK OVER THE AREA. AS OF RIGHT NOW...RESIDUAL OR
LEFTOVER MOISTURE SHOULD FOCUS WETTING THUNDERSTORM DEVELOPMENT OVER
THE NORTH CENTRAL MOUNTAINS AND PORTIONS OF THE NORTHEAST PLAINS.
THE PLUME OF MOISTURE SHOULD REINVIGORATE OVER WESTERN AND CENTRAL
NEW MEXICO DURING THE WEEKEND. HUMIDITY VALUES WOULD TREND UP. A
MONSOON BURST CONCENTRATING SIGNIFICANT MOISTURE AND STORMS WOULD BE
POSSIBLE DURING THIS PERIOD.
WEATHER MODELS TRY TO ELONGATE THE UPPER HIGH OVER PORTIONS OF NEW
MEXICO EARLY NEXT WEEK. RESIDUAL MOISTURE WOULD BE AROUND AND CAUGHT
WITHIN THIS UPPER HIGH ALTHOUGH STORMS WOULD BE MORE IN THE RECYCLE
MODE VERSUS A TRUE MONSOON BURST MODE. THUS THE WETTING RAIN
COVERAGE WOULD GRADUALLY DECLINE. WILL CONTINUE TO MONITOR THIS
TREND.
50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1030 PM EDT WED AUG 7 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 1030 PM EDT WEDNESDAY...BASED ON CURRENT RADAR AND RECENT
NAM/RAP/HRRR GUIDANCE TRENDS HAVE MADE FAIRLY SIGNIFICANT DOWNWARD
TWEAKS TO POPS TONIGHT INTO THURSDAY MORNING. ASIDE FOR SOME
SHOWERS THAT HAD MOVED ACROSS THE NORTHERN CHAMPLAIN VALLEY INTO
NORTHERN VERMONT...STEADIER/HEAVIER SHOWERS AND THUNDERSTORMS
REMAIN ACROSS EASTERN ONTARIO AND THE NORTHERN SHORE OF LAKE
ONTARIO. THE RADAR RETURNS ACROSS THE SAINT LAWRENCE VALLEY ARE
MERELY ANVIL SHADOWS...AND RECENT TRENDS SHOW BETTER CONVECTIVE
DEVELOPMENT TRAILING BACK ALONG THE NORTHERN SHORE OF LAKE ONTARIO
IN THE VICINITY OF THE TORONTO AREA. AS MENTIONED...FEEL THAT THE
NAM...RAP AND HRRR MODELS ARE CURRENTLY HANDLING PRESENT
CONDITIONS THE BEST AND HAVE THEREFORE ALIGNED THE FORECAST CLOSER
TO THAT SUITE OF GUIDANCE. SPECULATING THAT OTHER WETTER
GUIDANCE...E.G. THE GFS...MAY HAVE BEEN KEYING ON DEEPER MOISTURE
FEED WHICH THE EARLIER MCS OVER PA MAY HAVE TAPPED INTO.
NEVERTHELESS...STILL EXPECT SFC COLD FRONT ACROSS ONTARIO TO
APPROACH THE NORTH COUNTRY THROUGH OVERNIGHT BUT WILL ONLY BE
GOING WITH CHANCE TO HIGH CHANCE POPS THROUGH SUNRISE...AND THEN
SLIGHT CHANCE TO CHANCE THROUGH THE THURSDAY MORNING PERIOD.
CURRENT TEMPS/DEWPOINTS STILL LOOK ON TRACK AND IT SHOULD
OTHERWISE BE A CLOUDY...MILDER AND SLIGHTLY MORE HUMID NIGHT THAN
RECENTLY WITH LOWS IN THE UPPER 50S TO THE 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 341 PM EDT WEDNESDAY...THE EXTENDED PORTION OF THE FORECAST
WILL FEATURE PRETTY QUIET AND COOL WEATHER...NO SIGNIFICANT
CHANCES FOR PRECIPITATION. UPPER LEVEL LOW LIFTS NORTHEAST AND
AWAY FROM THE NORTH COUNTRY SATURDAY AND A RIDGE OF SURFACE HIGH
PRESSURE BUILDS INTO THE AREA. MAINLY DRY WEATHER IS EXPECTED
FROM SATURDAY THROUGH MONDAY. A LOW PRESSURE SYSTEM PASSING NORTH
OF OUR REGION ON MONDAY NIGHT WILL BRING A CHANCE FOR SOME
SHOWERS...THOUGH BEST DYNAMICS REMAIN WELL NORTH OF OUR FORECAST
AREA. TUESDAY THROUGH WEDNESDAY WILL ALSO BE QUIET WITH ANOTHER
RIDGE OF HIGH PRESSURE BUILDING INTO THE AREA.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...DIFFICULT AVIATION FORECAST OVER THE NEXT 24
HOURS AS MOST MODELS NOT HANDLING THE CURRENT CONDITIONS VERY
WELL. BROKEN LINE OF SHOWERS/STORMS ENTERING THE OTTAWA RIVER
VALLEY ASSOCIATED WITH A PRE-FRONTAL SURFACE TROUGH WILL SHIFT
EAST INTO THE NORTH COUNTRY OVERNIGHT WHILE DISSIPATING. HAVE PUT
IN SOME VCTS FOR KMSS/KSLK BUT ONLY VCSH EASTWARD AS INSTABILITY
WEAKENS BY THE TIME PRECIP GETS THERE. SCATTERED SHOWERS PERSIST
THROUGH 09-12Z ALONG WITH SOME MVFR CIGS...THEN DISSIPATE FOR THE
MORNING HOURS AS THE REAL COLD FRONT BEGINS TO MOVE INTO THE SAINT
LAWRENCE VALLEY. MAINLY VFR CONDITIONS ARE THEN EXPECTED THURSDAY
WITH SCATTERED SHOWERS AND POSSIBLY STORMS ARE LIKELY AGAIN FROM
THE CHAMPLAIN VALLEY EAST DURING THE AFTERNOON...THOUGH DIFFICULT
TO FORECAST TIMING AND LOCATION SO HAVE JUST GONE WITH SOME MORE
VCSH. WINDS REMAIN MODERATE AT 5-10 KNOTS THROUGH THE PERIOD...
GUSTING A BIT THIS EVENING AND AGAIN TOMORROW AFTERNOON.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
00Z FRIDAY THROUGH 00Z SATURDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
00Z SATURDAY THROUGH MONDAY...MAINLY VFR UNDER SURFACE HIGH PRESSURE.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...WGH/LOCONTO
SHORT TERM...WGH
LONG TERM...NEILES
AVIATION...LAHIFF
MARINE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS BUFFALO NY
846 PM EDT WED AUG 7 2013
.SYNOPSIS...
SOUTHERLY WINDS BETWEEN HIGH PRESSURE OFF THE EAST COAST AND A COLD
FRONT APPROACHING FROM THE MIDWEST WILL KEEP WARM AND MORE HUMID
CONDITIONS TO OUR AREA TONIGHT...ALONG WITH A CHANCE FOR A FEW
SHOWERS AND THUNDERSTORMS. SHOWERS AND THUNDERSTORMS WILL BECOME
MORE WIDESPREAD LATER TONIGHT AND THURSDAY MORNING AS THE FRONT MOVES
ACROSS WESTERN AND CENTRAL NEW YORK. SOMEWHAT UNSETTLED WEATHER WILL
LAST INTO FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
WESTERN NEW YORK IS IN A DRY SLOT LATE THIS EVENING IN THE WAKE OF
AN EXITING SHORTWAVE WHICH SPARKED AN MCS TO OUR SOUTH.
MEANWHILE...THERE IS FAIRLY UNSTABLE AIR IN PLACE (500 TO 1000
J/KG) BUT NO FOCUS TO TAP THIS ENERGY. THAT MIGHT CHANGE LATER
THIS EVENING...AS THE FRONTAL BOUNDARY ITSELF DROPS ACROSS THE REGION.
MODEL GUIDANCE HAS STRUGGLED IN HANDLING THIS CONVECTION...BUT IT
SEEMS THAT THE 18Z NAM AND HOURLY RUNS OF THE HRRR HAVE HAD THE
BEST HANDLE ON THIS. FOLLOWING THIS...EXPECT SHOWERS AND
THUNDERSTORMS ACROSS ONTARIO TO DROP SOUTHWARD DURING THE EVENING
HOURS...WITH WHATEVER REMAINS OF THIS ACTIVITY DROPPING SOUTH OF
LAKE ONTARIO AROUND OR SHORTLY AFTER MIDNIGHT. THE BEST CHANCE FOR
THUNDERSTORMS WILL BE EAST OF LAKE ONTARIO...WHERE UPSTREAM
CONVECTION IS MOST VIGOROUS. ELSEWHERE IT REMAINS A BIT UNCERTAIN
HOW SOLID THE LINE WILL BE...WITH ONLY SCATTERED UPSTREAM ACTIVITY
WEST OF TORONTO AND LONDON. FOR NOW WILL MAINTAIN LIKELY POPS FROM
BUF-ROC...THEN TAPER DOWN AS THE NIGHT GOES ON FIGURING CONVECTION
WILL TAPER OFF WITH THE LOSS OF HEATING AND THE STALLING FRONTAL BOUNDARY.
THE SEVERE WEATHER POTENTIAL FOR OUR REGION REMAINS QUITE
LIMITED...WITH THE MOST ORGANIZED CONVECTION UPSTREAM OF THE NORTH
COUNTRY. IT STILL APPEARS THAT THE STEADIEST SHOWERS AND
THUNDERSTORMS WILL OCCUR IN THE 11 PM TO 4 AM TIME FRAME.
FOR THURSDAY...THE FRONTAL BOUNDARY WILL BE STALLED ACROSS OUR
REGION. THERE WILL BE A MARGINAL CHANCE FOR SHOWERS IN THE
MORNING...WITH INCREASING CHANCES DURING THE AFTERNOON HOURS WILL
ANY MODEST DAYTIME HEATING...AND DEVELOPING LAKE BREEZE
CONVERGENCE BOUNDARIES.
FOR TEMPERATURES...THE CONTINUED INFLUX OF WARM AND HUMID AIR
THROUGH THE NIGHT...THE OVERNIGHT LOWS WILL BE IN THE MIDDLE TO
UPPER 60S AND EVEN NEAR 70 IN DOWNSLOPING AREAS ACROSS THE LAKE
PLAINS AND IN URBAN AREAS. WITH THE SLOW PASSAGE OF THE COL FRONT
ON THURSDAY...EXPECT HIGH TEMPS TO REACH THE UPPER 70S TO LOWER
80S.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
MATURE SURFACE LOW PRESSURE AND PARENT UPPER LEVEL LOW WILL BE
CENTERED OVER NORTHERN ONTARIO PROVINCE NEAR THE HUDSON BAY THURSDAY
EVENING. A COLD FRONT ORIENTED FROM A TRIPLE POINT LOW OVER THE
CANADIAN MARITIMES SOUTHWEST ACROSS THE ADIRONDACKS TO THE OHIO VALLEY
WILL BE STALLING/SLOWING AS IT BECOMES PARALLEL WITH THE UPPER LEVEL
FLOW. A SURFACE WAVE WILL LIFT NORTHEAST ALONG THE FRONT THURSDAY
EVENING. A SWATH OF SHOWERS ASSOCIATED WITH THIS WAVE AND POSSIBLY
SOME EMBEDDED LIGHTING LOOKS TO SHIFT ACROSS THE SOUTHERN TIER INTO
THE FINGER LAKES AND ACROSS CENTRAL NEW YORK IN THE EVENING. ITS
NORTHERN EDGE MAY EVEN BRING SOME LIGHT RAIN TO THE NIAGARA
FRONTIER. THE SHOWERS WILL SHIFT EAST INTO CENTRAL AND EASTERN
NEW YORK OVERNIGHT.
THE SURFACE WAVE WILL SHIFT NORTH ACROSS NEW ENGLAND THROUGH FRIDAY
WHILE ACTING TO SHOVE THE COLD FRONT WELL SOUTH AND EAST OF THE
FORECAST AREA. A CHANCE OF RAIN WILL LINGER ACROSS THE FINGER LAKES
AND NORTH COUNTY FRIDAY MORNING OTHERWISE EXPECT WESTERN AND NORTH
CENTRAL NEW YORK TO BE RAIN FREE BY MID-AFTERNOON BEHIND THE FRONT.
THE 12Z NAM IS THE ONLY OUTLIER IN THIS SCENARIO AS IT FORECASTS A
SECOND SURFACE WAVE TO LIFT ALONG THE FRONT EARLY FRIDAY WITH
ANOTHER ROUND OF RAIN ACROSS WNY THROUGH THE AFTERNOON. THIS IDEA HAS
BEEN DISCOUNTED WITH THE MAJORITY OF FORECAST MODELS SHOWING DRY
CONDITIONS ON FRIDAY. CANADIAN PRAIRIE SOURCED HIGH PRESSURE WILL
BUILD ACROSS THE GREAT LAKES REGION THROUGH FRIDAY AND INTO SATURDAY
WITH SEASONABLY COOL TEMPERATURES AND DRY SUNNY CONDITIONS TO START
OFF THE WEEKEND.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AN AMPLIFIED WESTERN RIDGE AND EASTERN TROUGH 500MB PATTERN WILL BE IN
PLACE ACROSS SOUTHERN CANADA OVER THE WEEKEND. ZONAL FLOW IN THE
BASE OF THE EASTERN CANADIAN TROUGH WILL EXTENDING FROM THE NORTHERN
PLAINS EAST ACROSS THE GREAT LAKES TO THE NORTHEAST STATES. THIS
SHOULD KEEP SEASONABLY COOL AND DRY WEATHER IN PLACE FOR AT LEAST
SUNDAY AND MONDAY. MEDIUM RANGE MODELS THEN SHOW THE NEXT STRONG
VORTICITY MAX/DISTURBANCE TO DROP INTO THE BASE OF THIS TROUGH
ACROSS THE GREAT LAKES MONDAY NIGHT AND LIFTING INTO ATLANTIC CANADA
ON TUESDAY. THE 00Z ECMWF IS MUCH DRIER AHEAD OF THE TROUGH AXIS
THAN THE 12Z GFS SHOWING JUST A LIMITED SHOWER THREAT. THE GFS SHOWS
MORE OF A FRONTAL ORIENTATION.
HAVE ONLY INCLUDED A SLIGHT CHANCE OF SHOWERS FOR NOW MONDAY NIGHT
IN TO TUESDAY UNTIL MORE MODEL AGREEMENT CAN BE MADE. BY WEDNESDAY
HIGH PRESSURE EITHER LINGERS OR BUILDS BACK ACROSS NEW YORK DEPEND
ON WHICH MODEL YOU LOOK AT BUT WILL KEEP WEDNESDAY DRY. THE
LINGERING TROUGH OVER EASTERN CANADA WILL KEEP SEASONABLY COOL
TEMPERATURES IN PLACE ACROSS THE FORECAST AREA THROUGH MID NEXT WEEK
WITH NO STRONG CONNECTION TO THE GULF OR ATLANTIC.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
FOR THE 00Z TAF CYCLE...EXPECT MOSTLY VFR CONDITIONS THIS
EVENING...AS THE REGION IS IN A DRY SLOT. SHOWERS AND
THUNDERSTORMS ALONG A FRONTAL BOUNDARY WILL DROP FROM N-S ACROSS
THE REGION LATE TONIGHT...GRADUALLY WEAKENING AS THEY DO.
THUNDERSTORMS MAY BRING BRIEF PERIODS OF HEAVY RAIN...LOWERING
VSBY TO 2SM OR LESS.
OUTSIDE OF THUNDERSTORMS...EXPECT MAINLY VFR CONDITIONS.
LINGERING LOW MOISTURE MAY RESULT IN SOME LOW CLOUDS OR FOG AT
JHW...OR BRIEF PERIODS OF MVFR CIGS ELSEWHERE. ON
THURSDAY...EXPECT ONLY SCATTERED LIGHT SHOWERS IN THE
MORNING...WITH SHOWERS AND THUNDERSTORMS A BIT MORE WIDESPREAD
DURING THE AFTERNOON HOURS.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS.
SATURDAY AND SUNDAY...VFR.
MONDAY...VFR WITH CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
AS A COLD FRONT CROSSES THE CENTRAL LAKES LATE TONIGHT AND EASTERN
LAKES ON THURSDAY...THE WINDS WILL SWITCH TO THE WEST SOUTHWEST AND
DIMINISH. HIGH PRESSURE IS FORECAST TO SETTLE ACROSS THE EASTERN
LAKES ON FRIDAY. SMALL CRAFT ADVISORY CONDITIONS ARE NOT EXPECTED.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...APFFEL
MARINE...APFFEL/WCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
743 PM EDT WED AUG 7 2013
.SYNOPSIS...
RAIN AND THUNDER CHANCES INCREASE THIS EVENING, AS A COLD FRONT
MOVES SOUTHEAST TOWARDS THE AREA. THIS FEATURE WILL THEN STALL
WEST OF THE AREA BY MORNING, KEEPING THE THREAT FOR CONTINUED
SHOWERS AND STORMS IN THE FORECAST THROUGH THE REMAINDER OF THE
WORK WEEK. THIS FRONTAL PASSAGE LOOKS TO FINALLY OCCUR FRIDAY
EVENING.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
545 PM UPDATE...
WITH CLOUDY SKIES AND MARINE LAYER SHOWERS ARE NOT MATERIALIZING.
LOWERED POPS. A FEW SHOWERS AND TSTORMS FORMED IN WRN NY AND WRN
PA BUT THEY ARE DYING AS THEY MOVE EAST. BULK OF PA PRECIP WILL
MISS TO THE SOUTH AND VERY LITTLE IN NY. SEE NO REASON WHY THE
MARINE LAYER WITH COOL TEMPS WILL NOT REMAIN THROUGH THE NIGHT.
245 PM UPDATE...
SFC LOPRES JUST SOUTH OF HUDSON BAY HAS DRAPED A CDFNT DOWN ACRS LK
HURON AND SWWRD INTO NRN MO. AT THE SAME TIME CONVECTION THAT DVLPD
OVRNGT HAS THROWN OUT A GUST FRONT AND HAS ALLOWED STORMS TO DVLP
ACRS NRN OH. MAIN AREA OF STORMS ACRS SRN ONTARIO HAS LIFTED NORTH
AS EXPECTED WITH MAIN S/WV ROTATING ARND BASE OF HUDSON BAY TROF.
TIMING ON THIS AFOREMENTIONED LINE OF STORMS PLACES IT INTO EXTRM WRN
ZONES BY 21Z THIS AFTN AND WL WORK TWD CNTRL PART OF CWA BY 00Z.
THIS LOOKS TO BE KICKED OFF BY S/WV WORKING ITS WAY EAST ACRS NRN OH
AND IT APPEARS TO BE HEADING A LITTLE SOUTH OF EAST. THUS, WL
MAINTAIN LKLY POPS THRU TONIGHT WITH CONTINUAL MOISTURE BEING PUMPED
INTO REGION ON LLJ AND PW VALUES INCRSG TO NEAR 1.50 INCHES AND ANY
SUBTLE S/WVS THAT ENCROACH UPON THE AREA. BULLSEYE OF QPF ALONG THE
I-81 CORRIDOR ADVERTISED BY 12Z GFS AND LATEST RAP APPEARS TO BE A
RESULT OF CONVECTIVE FEEDBACK AND HV DISCOUNTED THIS SOLN. THINK
THAT AREAL AVGS WL LKLY BE BETWEEN 0.25 AND 0.50 INCHES.
AS FOR OVRNGT MINS DO NOT THINK TEMPS WL MV MUCH AS CLDS RMN
ENTRENCHED OVR AREA. FCST LOWS WL BOTTOM OUT IN THE L/M 60S.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
245 PM UPDATE...
FRONTAL BNDRY WL STALL OUT THUR MRNG JUST TO THE WEST OF THE AREA
AND RMN THERE INTO FRIDAY. VRY LITTLE MIXING WL OCCUR DRG THE DAY AS
AREA WL LKLY BE SOCKED IN WITH CLDS ONCE AGAIN. MAX TEMPS WL JUST
BARELY TOP OUT IN THE 80S. CAPES WL BE SIMILAR TO WED WITH VALUES
APPCHG 1000 J/KG BUT WIND SHEAR IS EXPECTED TO DROP OFF DRG THE DAY.
PW VALUES PROGGED TO APPCH 2.00 INCHES DRG THE DAY THUS ANY STORM
THAT DVLPS MAY PRODUCE MODERATE TO HVY RAIN.
LKLY POPS WL CONTINUE TOMORROW NGT AS BNDRY RMNS STALLED OUT TO THE
WEST. MED RANGE MODELS HINTING AT SFC LOPRES RIDING UP ALONG THE
FRONT THU NGT AND HELPING GIVE THE FRONT A LITTLE SHOVE TO THE
SOUTH.
FROPA NOW LOOKS TO OCCUR DRG THE DAY FRIDAY. THUS, HV TAKEN OUT PCPN
AFT 12Z SATURDAY. NO OTHER CHGS NEEDED TO THE END OF THE SHORT TERM
WITH PERHAPS SOME LINGERING SHOWERS ON FRIDAY WITH RMNG UL WV MVG
THRU BHND FRONT. ELONGATED VORT MAX PROGGED TO MV THRU ON SATURDAY
BUT WITH DRY AIRMASS IN PLACE NOT EXPECTING MUCH MORE THAN CLDS AT
THIS POINT.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO SUNDAY.
FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND POSITIONING
OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH MIDWEEK CAUSING
SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
UPR WV AND WRM FNT FEATURE PUSHING THRU ATTM. HWVR...STUBBORN SELY
FLOW WILL KEEP A MARINE LYR IN THE AREA FOR MUCH OF THE NGT
KEEPING CIGS IN THE MVFR RANGE...WITH BRIEF MVFR VSBYS PSBL. DRIER
AIR BEGINS TO WORK INTO THE AREA ON THU AHD OF A SFC COLD FNT SO
XPCT CIGS AND VSBYS TO CLIMB INTO THE VFR RANGE. BEST CHANCE OF
TSRA TMRW WILLBE OVER NEPA AND AVP WHERE BETTER INSTABILITY WILL
DVLP. BRIEF MVFR CIGS AND VSBY PSBL THERE.
OUTLOOK...
THU NGT...MVFR IN SHRA AND TSRA.
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN/TAC
NEAR TERM...PVN/TAC
SHORT TERM...PVN
LONG TERM...BMW
AVIATION...BMW/DGM
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
740 PM EDT WED AUG 7 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 714 PM EDT WEDNESDAY...REGIONAL COMPOSITE RADAR SHOWS ONLY
VERY LIGHT SHOWERS ACROSS THE ADIRONDACKS...IN FACT MUCH OF IT
ISN`T EVEN REACHING THE GROUND WITH ONLY POTSDAM AND MASSENA NY
NOTING LIGHT RAIN. FURTHER WEST...A BROKEN LINE OF CONVECTION HAS
DEVELOPED ACROSS LAKE ONTARIO AND BACK INTO CENTRAL ONTARIO. RAP
ANALYSIS DO SHOW CAPES IN EXCESS OF 1000 J/KG AND SHOWALTERS
BETWEEN -1 TO -2 IN THE SAINT LAWRENCE VALLEY AREA. THE STORMS MAY
ALSO BE TAPPING INTO SOME DYNAMIC SUPPORT ON THE SOUTHERN EDGE OF
A VORTICITY MAXIMA EXITING INTO CENTRAL QC. SO ONE CHANGE WAS TO
INCLUDE SLIGHT CHANCE MENTION OF THUNDERSTORMS IN FOR THE SAINT
LAWRENCE VALLEY INTO THE NORTHERN ADIRONDACKS WITH THE THUNDER
THREAT TO DIMINISH THRU LATE EVENING. STILL THINK GENERAL START OF
SHOWERS IN VERMONT UNTIL LATE EVENING/AFTER MIDNIGHT LOOKS
GOOD...BUT THERE`S SOME QUESTION FROM RECENT NEAR-TERM GUIDANCE
AS TO HOW LONG THE RAIN SHOWERS LAST. HRRR REFLECTIVITY PROGS
DON`T SHOW MUCH ACTIVITY AT ALL WHILE LOCAL BTV4/BTV12 GUIDANCE
SUGGEST THAT SHOWERS PUSH THROUGH VERMONT BUT BEGIN TO WEAKEN.
MOST OF THE GUIDANCE KEEP RAIN GOING...BUT THE EVIDENT DRY SLOT ON
WV IMAGERY AND FAST WEST FLOW ALOFT ALSO SUGGEST THE HRRR IDEA
CAN`T BE TOTALLY DISCOUNTED EITHER. WILL AWAIT UPCOMING GUIDANCE
COMING IN LATER THIS EVENING BEFORE MAKING ANY SIGNIFICANT CHANCES
TO POPS AFTER MIDNIGHT. OTHERWISE...REST OF FORECAST REMAINS ON
TRACK.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 341 PM EDT WEDNESDAY...THE EXTENDED PORTION OF THE FORECAST
WILL FEATURE PRETTY QUIET AND COOL WEATHER...NO SIGNIFICANT
CHANCES FOR PRECIPITATION. UPPER LEVEL LOW LIFTS NORTHEAST AND
AWAY FROM THE NORTH COUNTRY SATURDAY AND A RIDGE OF SURFACE HIGH
PRESSURE BUILDS INTO THE AREA. MAINLY DRY WEATHER IS EXPECTED
FROM SATURDAY THROUGH MONDAY. A LOW PRESSURE SYSTEM PASSING NORTH
OF OUR REGION ON MONDAY NIGHT WILL BRING A CHANCE FOR SOME
SHOWERS...THOUGH BEST DYNAMICS REMAIN WELL NORTH OF OUR FORECAST
AREA. TUESDAY THROUGH WEDNESDAY WILL ALSO BE QUIET WITH ANOTHER
RIDGE OF HIGH PRESSURE BUILDING INTO THE AREA.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...DIFFICULT AVIATION FORECAST OVER THE NEXT 24
HOURS AS MOST MODELS NOT HANDLING THE CURRENT CONDITIONS VERY
WELL. BROKEN LINE OF SHOWERS/STORMS ENTERING THE OTTAWA RIVER
VALLEY ASSOCIATED WITH A PRE-FRONTAL SURFACE TROUGH WILL SHIFT
EAST INTO THE NORTH COUNTRY OVERNIGHT WHILE DISSIPATING. HAVE PUT
IN SOME VCTS FOR KMSS/KSLK BUT ONLY VCSH EASTWARD AS INSTABILITY
WEAKENS BY THE TIME PRECIP GETS THERE. SCATTERED SHOWERS PERSIST
THROUGH 09-12Z ALONG WITH SOME MVFR CIGS...THEN DISSIPATE FOR THE
MORNING HOURS AS THE REAL COLD FRONT BEGINS TO MOVE INTO THE SAINT
LAWRENCE VALLEY. MAINLY VFR CONDITIONS ARE THEN EXPECTED THURSDAY
WITH SCATTERED SHOWERS AND POSSIBLY STORMS ARE LIKELY AGAIN FROM
THE CHAMPLAIN VALLEY EAST DURING THE AFTERNOON...THOUGH DIFFICULT
TO FORECAST TIMING AND LOCATION SO HAVE JUST GONE WITH SOME MORE
VCSH. WINDS REMAIN MODERATE AT 5-10 KNOTS THROUGH THE PERIOD...
GUSTING A BIT THIS EVENING AND AGAIN TOMORROW AFTERNOON.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
00Z FRIDAY THROUGH 00Z SATURDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
00Z SATURDAY THROUGH MONDAY...MAINLY VFR UNDER SURFACE HIGH PRESSURE.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...WGH/LOCONTO
SHORT TERM...WGH
LONG TERM...NEILES
AVIATION...LAHIFF
MARINE...MUCCILLI
EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
714 PM EDT WED AUG 7 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 714 PM EDT WEDNESDAY...REGIONAL COMPOSITE RADAR SHOWS ONLY
VERY LIGHT SHOWERS ACROSS THE ADIRONDACKS...IN FACT MUCH OF IT
ISN`T EVEN REACHING THE GROUND WITH ONLY POTSDAM AND MASSENA NY
NOTING LIGHT RAIN. FURTHER WEST...A BROKEN LINE OF CONVECTION HAS
DEVELOPED ACROSS LAKE ONTARIO AND BACK INTO CENTRAL ONTARIO. RAP
ANALYSES DO SHOW CAPES IN EXCESS OF 1000 J/KG AND SHOWALTERS
BETWEEN -1 TO -2 IN THE SAINT LAWRENCE VALLEY AREA. THE STORMS MAY
ALSO BE TAPPING INTO SOME DYNAMIC SUPPORT ON THE SOUTHERN EDGE OF
A VORTICITY MAXIMA EXITING INTO CENTRAL QC. SO ONE CHANGE WAS TO
INCLUDE SLIGHT CHANCE MENTION OF THUNDERSTORMS IN FOR THE SAINT
LAWRENCE VALLEY INTO THE NORTHERN ADIRONDACKS WITH THE THUNDER
THREAT TO DIMINISH THRU LATE EVENING. STILL THINK GENERAL START OF
SHOWERS IN VERMONT UNTIL LATE EVENING/AFTER MIDNIGHT LOOKS
GOOD...BUT THERE`S SOME QUESTION FROM RECENT NEAR-TERM GUIDANCE
AS TO HOW LONG THE RAIN SHOWERS LAST. HRRR REFLECTIVITY PROGS
DON`T SHOW MUCH ACTIVITY AT ALL WHILE LOCAL BTV4/BTV12 GUIDANCE
SUGGEST THAT SHOWERS PUSH THROUGH VERMONT BUT BEGIN TO WEAKEN.
MOST OF THE GUIDANCE KEEP RAIN GOING...BUT THE EVIDENT DRYSLOT ON
WV IMAGERY AND FAST WEST FLOW ALOFT ALSO SUGGEST THE HRRR IDEA
CAN`T BE TOTALLY DISCOUNTED EITHER. WILL AWAIT UPCOMING GUIDANCE
COMING IN LATER THIS EVENING BEFORE MAKING ANY SIGNIFICANT CHANCES
TO POPS AFTER MIDNIGHT. OTHERWISE...REST OF FORECAST REMAINS ON
TRACK.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 341 PM EDT WEDNESDAY...THE EXTENDED PORTION OF THE FORECAST
WILL FEATURE PRETTY QUIET AND COOL WEATHER...NO SIGNIFICANT
CHANCES FOR PRECIPITATION. UPPER LEVEL LOW LIFTS NORTHEAST AND
AWAY FROM THE NORTH COUNTRY SATURDAY AND A RIDGE OF SURFACE HIGH
PRESSURE BUILDS INTO THE AREA. MAINLY DRY WEATHER IS EXPECTED
FROM SATURDAY THROUGH MONDAY. A LOW PRESSURE SYSTEM PASSING NORTH
OF OUR REGION ON MONDAY NIGHT WILL BRING A CHANCE FOR SOME
SHOWERS...THOUGH BEST DYNAMICS REMAIN WELL NORTH OF OUR FORECAST
AREA. TUESDAY THROUGH WEDNESDAY WILL ALSO BE QUIET WITH ANOTHER
RIDGE OF HIGH PRESSURE BUILDING INTO THE AREA.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
THROUGH 18Z THURSDAY...-RW DEVELOPS IN N NY...W/ CONDITIONS
DROPPING THRU REST OF FORECAST PERIOD AS FRNT PUSH THRU
AREA...MAINLY OVERNIGHT. LOOKING FOR VFR TO DROP DOWN TO IFR/MVFR
MIX BY 03Z THURS...WITH VSBY 2-6SM AND CEILINGS BKN020-040. WINDS
SSE TO SSW 5-15KTS W/ GUSTS NEAR 20KTS IN THE CVLY. TRW ALSO
POSSIBLE BY 00Z. CONDITIONS WILL IMPROVE AT ALL TAF SITES BY ABOUT
12Z THURSDAY...THOUGH SOME MVFR CIGS STILL POSSIBLE.
OUTLOOK 18Z THURSDAY THROUGH SUNDAY...
18Z THURSDAY THROUGH 06Z FRIDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
06Z FRIDAY THROUGH SUNDAY...MAINLY VFR UNDER SURFACE HIGH
PRESSURE WITH ISOLATED SHOWERS ACROSS THE HIGHER TERRAIN POSSIBLE
SATURDAY AFTERNOON.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...WGH/LOCONTO
SHORT TERM...WGH
LONG TERM...NEILES
AVIATION...NEILES
MARINE...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
920 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE
NORTHEAST THEN MOVE OFFSHORE OVER THE NEXT SEVERAL DAYS. AS THE
RIDGE LOSES ITS GRIP ACROSS THE REGION THE WINDS WILL BECOME
SOUTHERLY ALLOWING THE RETURN OF WARMER AND MORE HUMID AIR INTO THE
CAROLINAS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA
MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 745 PM WEDNESDAY...LATEST IR SAT IMAGERY IE. THE 11-3.9
MICRON CHANNEL A FAVORITE AMONGST US FOR NIGHT-TIME
SURVEILLANCE...INDICATES CLOUDINESS HAS THINNED OUT...ESPECIALLY
ALONG AND EAST OF THE I-95 CORRIDOR. MODELS ARE ONCE AGAIN BEHIND
THE 8-BALL IN TERMS OF SKY CONDITIONS THIS EVENING...AND LIKELY
FOR THE OVERNIGHT PERIOD. THE W TO NW...DOWNSLOPE.. FLOW IN THE
MID-UPPER LEVELS HAS BEEN A STRONGER PLAYER IN THE SCOURING OF
THE CLOUDINESS ACROSS THE ILM CWA THEN POSSIBLY WHAT THE MODELS
TAKE INTO ACCOUNT. WILL THEREFORE LEAN TOWARD A MORE OPTIMISTIC
SKY CONDITION FOR THE OVERNITE. THE FLY IN THE OINTMENT WILL BE
ALONG THE IMMEDIATE COAST...WHERE RENEGADE LOW CLOUDS COULD
BRIEFLY MOVE ONSHORE. HAVE CONTINUED WITH CURRENT THINKING WITH
REGARDS TO KEEPING POPS OVER THE ADJACENT ATL WATERS...WITH NO
ONSHORE MOVEMENT. MIN TEMP FORECAST ALREADY ON THE LOW SIDE OF
GUIDANCE. GIVEN THE DECREASE IN THE AMOUNT OF CLOUDS AND NEARLY
CALM WINDS...SEE NO REASON TO DETOUR FROM THIS LOW TEMP FCST.
PREVIOUS DISCUSSION.............................................
AS OF 2 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM
THE NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF
INTERSTATE 95.
THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME
OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING
ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY
WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING
ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE
SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND
WESTERN WILLIAMSBURG COUNTY.
A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE
PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE
COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY
WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO
MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE
HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS
CONTINUE.
MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES
RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS
MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS
SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE
SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR
THE BEACHES AROUND SUNRISE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...THE ATMOSPHERE WILL BE TRANSITIONING BACK TO
A MORE TYPICAL SUMMERTIME PATTERN WITH HIGH PRESSURE SETTING UP OFF
THE COAST ALLOWING FOR THE RETURN OF MORE HUMID CONDITIONS. AN H5
SUBTROPICAL RIDGE WILL BECOME PINCHED FROM THE SOUTHEAST U.S.
WESTWARD TO THE LOWER MS VALLEY AND TX...WITH A STRONG SHORTWAVE
PUSHING ACROSS SOUTHEAST CANADA AND WESTWARD MOVING H5 TROFS OVER
THE GULF OF MEXICO. DON/T THINK THE AIR-MASS WILL BECOME STRONGLY
CAPPED ACROSS THE FORECAST AREA AND WITH SUFFICIENT INSTABILITY
EXPECT WIDELY SCATTERED SHOWERS/TSTMS EACH DAY. THE SEA BREEZE FRONT
WILL BE THE PRIMARY LIFTING MECHANISM...MORE-SO IN THE AFTERNOON AND
EARLY EVENING. MAX/MIN TEMPS WILL BE AT OR ABOVE CLIMO EACH PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 2 PM WEDNESDAY...ELONGATED MID LEVEL RIDGE WILL START TO BREAK
DOWN EARLY NEXT WEEK WITH LONGWAVE 5H TROUGH SETTING UP OVER THE
EAST COAST BY THE END OF THE PERIOD. THE PERIOD WILL START OFF WARM
AND RELATIVELY DRY...HIGHS IN THE LOW TO MID 90S AND LOWS IN THE LOW
TO MID 70S WITH SLIGHT CHC TO LOW CHC POP. CONVECTION IS LIKELY TO
BE DIURNAL IN NATURE AND ASSOCIATED WITH THE SEA BREEZE AND PIEDMONT
TROUGH. BREAK DOWN OF THE RIDGE AND RETREATING BERMUDA HIGH ALLOWS A
COLD FRONT TO DROP IN FROM THE NORTHWEST ON MON. MID LEVEL TROUGH
AXIS NEVER MOVES OFF THE COAST AND THE FRONT ENDS UP LAYING PARALLEL
TO THE STEERING FLOW. THIS WILL KEEP THE FRONT STALLED IN THE AREA
THROUGH WED. ABUNDANT DEEP MOISTURE IN THE PRESENCE OF THE
BOUNDARY...ALONG WITH OCCASIONAL SHORTWAVES PASSING OVERHEAD IN
SOUTHEAST FLOW WILL ELEVATE POP CHANCES FOR SECOND HALF OF THE
PERIOD. WILL KEEP POP IN CHC CAT BUT INCREASE TO 40-50 ALONG WITH
LOWERING HIGHS. LOWS WILL LIKELY REMAIN IN THE LOW TO MID 70S AS
COOLER AIR REMAINS TRAPPED NORTHWEST OF THE REGION AND CLOUD COVER
WILL LINGER. THINK COVERAGE OF PRECIP WILL DECREASE OVERNIGHT BUT
SHOWERS ARE LIKELY TO LINGER OVERNIGHT SO WILL MAINTAIN LOW CHC POP.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...EXPECT VFR THROUGH THE VALID PERIOD WITH THE EXCEPTION
OF MVFR/POSSIBLE IFR DUE TO FOG/LOW CIGS LATE OVERNIGHT INTO THE
EARLY MORNING HOURS ON THURSDAY.
LIGHT WINDS AND FEW/SCT CLOUDS WILL CONTINUE INTO THE OVERNIGHT
HOURS. GIVEN LATEST TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS...ANTICIPATE
MVFR ALONG THE COAST AND POSSIBLE IFR/LIFR INLAND DUE TO FOG
DEVELOPMENT AND LOW CIGS LATE OVERNIGHT INTO THE EARLY MORNING
HOURS. AFTER DAYBREAK ON THURSDAY...CONDITIONS WILL IMPROVE TO VFR
WITH LIGHT WINDS. AS HIGH PRESSURE SHIFTS ABOUT THE AREA...WINDS
WILL BECOME SOUTHWEST BY THE AFTERNOON HOURS WITH SUSTAINED WINDS
AOB 12 KTS...BECOMING LIGHT INTO THE EVENING HOURS...WITH MID AND
HIGH CLOUDS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 815 PM WEDNESDAY...RIDGE AXIS EXTENDING SW FROM THE HIGHS
CENTER WELL OFFSHORE FROM THE NE STATES...WILL REMAIN NORTH OF THE
ILM COASTAL WATERS AS IT RIDGES INLAND. THIS WILL RESULT WITH ONSHORE
SE WINDS CONTINUING ACROSS THE COASTAL WATERS OVERNIGHT. THE SFC
PG WILL REMAIN RATHER LOOSE...PRODUCING AROUND 10 KT WIND SPEEDS.
MODELS REMAIN SOMEWHAT DIFFERENT WITH REGARD TO THE HANDLING OF
THE COASTAL TROF...MEANING ITS STRENGTH AND EVENTUAL MOVEMENT
ACROSS THE WATERS DURING LATE TONIGHT AND INTO THE BEGINNING OF
THE SHORT TERM PERIOD. FOR NOW...WILL CONTINUE TO MENTION ISOLATED
PCPN ASSOCIATED WITH IT LATER TONIGHT. SIGNIFICANT SEAS WILL BE
AROUND 2 FT...WITH 3 FOOTERS POSSIBLE FROM OFF CAPE FEAR
NORTHWARD IN ASSOCIATION WITH THE COASTAL TROF. WIND DRIVEN WAVES
WILL AGAIN DOMINATE SIGNIFICANT SEAS...WITH 2 SETS OF WIND WAVES
AT 3 AND 5-6 SECOND PERIODS.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...HIGH PRESSURE WILL PRESIDE OFFSHORE RESULTING
IN SOUTHERLY FLOW ACROSS THE COASTAL WATERS DURING THE SHORT TERM
PERIOD. THE PRESSURE GRADIENT WILL LIKELY SUPPORT WINDS IN THE 10-15
KT RANGE...WITH SOME ENHANCEMENT EACH DAY FROM THE SEA BREEZE
CIRCULATION. SEAS WILL LIKELY AVERAGE 3 FT AWAY FROM THE COAST
THURSDAY AND 3-4 FT BY FRIDAY AFTERNOON...WITH HIGHER FREQUENCY
WAVES DOMINATING THE WAVE SPECTRUM.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 2 PM WEDNESDAY...BERMUDA HIGH AND PIEDMONT TROUGH WILL
MAINTAIN SOUTH TO SOUTHWEST FLOW OVER THE WATERS THROUGH THE PERIOD.
RELATIVELY WEAK GRADIENT WILL KEEP SPEEDS IN THE 10 TO 15 KT RANGE
WITH HIGHEST VALUES IN THE AFTERNOON/EVENING. SPEEDS MAY INCREASE A
LITTLE LATE IN THE PERIOD AS COLD FRONT DROPS IN FROM THE NORTHWEST
AND PINCHES GRADIENT. SEAS OF 2 TO 4 FT WILL BE A COMBINATION OF
DOMINANT SOUTHERLY WIND WAVE AND EAST TO SOUTHEAST SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SRP
NEAR TERM...DCH/DRH
SHORT TERM...SRP
LONG TERM...III
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
857 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE
NORTHEAST THEN MOVE OFFSHORE OVER THE NEXT SEVERAL DAYS. AS THE
RIDGE LOSES ITS GRIP ACROSS THE REGION THE WINDS WILL BECOME
SOUTHERLY ALLOWING THE RETURN OF WARMER AND MORE HUMID AIR INTO THE
CAROLINAS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA
MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 745 PM WEDNESDAY...LATEST IR SAT IMAGERY IE. THE 11-3.9
MICRON CHANNEL A FAVORITE AMONGST US FOR NIGHT-TIME
SURVEILLANCE...INDICATES CLOUDINESS HAS THINNED OUT...ESPECIALLY
ALONG AND EAST OF THE I-95 CORRIDOR. MODELS ARE ONCE AGAIN BEHIND
THE 8-BALL IN TERMS OF SKY CONDITIONS THIS EVENING...AND LIKELY
FOR THE OVERNIGHT PERIOD. THE W TO NW...DOWNSLOPE.. FLOW IN THE
MID-UPPER LEVELS HAS BEEN A STRONGER PLAYER IN THE SCOURING OF
THE CLOUDINESS ACROSS THE ILM CWA THEN POSSIBLY WHAT THE MODELS
TAKE INTO ACCOUNT. WILL THEREFORE LEAN TOWARD A MORE OPTIMISTIC
SKY CONDITION FOR THE OVERNITE. THE FLY IN THE OINTMENT WILL BE
ALONG THE IMMEDIATE COAST...WHERE RENEGADE LOW CLOUDS COULD
BRIEFLY MOVE ONSHORE. HAVE CONTINUED WITH CURRENT THINKING WITH
REGARDS TO KEEPING POPS OVER THE ADJACENT ATL WATERS...WITH NO
ONSHORE MOVEMENT. MIN TEMP FORECAST ALREADY ON THE LOW SIDE OF
GUIDANCE. GIVEN THE DECREASE IN THE AMOUNT OF CLOUDS AND NEARLY
CALM WINDS...SEE NO REASON TO DETOUR FROM THIS LOW TEMP FCST.
PREVIOUS DISCUSSION...............................................
AS OF 2 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE
NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF
INTERSTATE 95.
THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME
OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING
ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY
WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING
ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE
SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND WESTERN
WILLIAMSBURG COUNTY.
A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE
PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE
COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY
WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO
MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE
HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS
CONTINUE.
MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES
RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS
MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS
SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE
SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR
THE BEACHES AROUND SUNRISE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...THE ATMOSPHERE WILL BE TRANSITIONING BACK TO
A MORE TYPICAL SUMMERTIME PATTERN WITH HIGH PRESSURE SETTING UP OFF
THE COAST ALLOWING FOR THE RETURN OF MORE HUMID CONDITIONS. AN H5
SUBTROPICAL RIDGE WILL BECOME PINCHED FROM THE SOUTHEAST U.S.
WESTWARD TO THE LOWER MS VALLEY AND TX...WITH A STRONG SHORTWAVE
PUSHING ACROSS SOUTHEAST CANADA AND WESTWARD MOVING H5 TROFS OVER
THE GULF OF MEXICO. DON/T THINK THE AIR-MASS WILL BECOME STRONGLY
CAPPED ACROSS THE FORECAST AREA AND WITH SUFFICIENT INSTABILITY
EXPECT WIDELY SCATTERED SHOWERS/TSTMS EACH DAY. THE SEA BREEZE FRONT
WILL BE THE PRIMARY LIFTING MECHANISM...MORE-SO IN THE AFTERNOON AND
EARLY EVENING. MAX/MIN TEMPS WILL BE AT OR ABOVE CLIMO EACH PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 2 PM WEDNESDAY...ELONGATED MID LEVEL RIDGE WILL START TO BREAK
DOWN EARLY NEXT WEEK WITH LONGWAVE 5H TROUGH SETTING UP OVER THE
EAST COAST BY THE END OF THE PERIOD. THE PERIOD WILL START OFF WARM
AND RELATIVELY DRY...HIGHS IN THE LOW TO MID 90S AND LOWS IN THE LOW
TO MID 70S WITH SLIGHT CHC TO LOW CHC POP. CONVECTION IS LIKELY TO
BE DIURNAL IN NATURE AND ASSOCIATED WITH THE SEA BREEZE AND PIEDMONT
TROUGH. BREAK DOWN OF THE RIDGE AND RETREATING BERMUDA HIGH ALLOWS A
COLD FRONT TO DROP IN FROM THE NORTHWEST ON MON. MID LEVEL TROUGH
AXIS NEVER MOVES OFF THE COAST AND THE FRONT ENDS UP LAYING PARALLEL
TO THE STEERING FLOW. THIS WILL KEEP THE FRONT STALLED IN THE AREA
THROUGH WED. ABUNDANT DEEP MOISTURE IN THE PRESENCE OF THE
BOUNDARY...ALONG WITH OCCASIONAL SHORTWAVES PASSING OVERHEAD IN
SOUTHEAST FLOW WILL ELEVATE POP CHANCES FOR SECOND HALF OF THE
PERIOD. WILL KEEP POP IN CHC CAT BUT INCREASE TO 40-50 ALONG WITH
LOWERING HIGHS. LOWS WILL LIKELY REMAIN IN THE LOW TO MID 70S AS
COOLER AIR REMAINS TRAPPED NORTHWEST OF THE REGION AND CLOUD COVER
WILL LINGER. THINK COVERAGE OF PRECIP WILL DECREASE OVERNIGHT BUT
SHOWERS ARE LIKELY TO LINGER OVERNIGHT SO WILL MAINTAIN LOW CHC POP.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...EXPECT VFR THROUGH THE VALID PERIOD WITH THE EXCEPTION
OF MVFR/POSSIBLE IFR DUE TO FOG/LOW CIGS LATE OVERNIGHT INTO THE
EARLY MORNING HOURS ON THURSDAY.
LIGHT WINDS AND FEW/SCT CLOUDS WILL CONTINUE INTO THE OVERNIGHT
HOURS. GIVEN LATEST TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS...ANTICIPATE
MVFR ALONG THE COAST AND POSSIBLE IFR/LIFR INLAND DUE TO FOG
DEVELOPMENT AND LOW CIGS LATE OVERNIGHT INTO THE EARLY MORNING
HOURS. AFTER DAYBREAK ON THURSDAY...CONDITIONS WILL IMPROVE TO VFR
WITH LIGHT WINDS. AS HIGH PRESSURE SHIFTS ABOUT THE AREA...WINDS
WILL BECOME SOUTHWEST BY THE AFTERNOON HOURS WITH SUSTAINED WINDS
AOB 12 KTS...BECOMING LIGHT INTO THE EVENING HOURS...WITH MID AND
HIGH CLOUDS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...WINDS ARE NOW LIGHT FROM THE EAST AT 10 KNOTS
WITH SEAS RUNNING AROUND 2 FEET. WITH THE SOUTHEASTERLY FLOW THERE
HAS BEEN A SLIGHT INCREASE IN SHOWERS OVER THE WATER AS A SMALL
CYCLONIC FEATURE HAS BEEN OBSERVED ON RADAR THE PAST COUPLE OF
HOURS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AS THEY PUSH TOWARDS
THE COAST.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...HIGH PRESSURE WILL PRESIDE OFFSHORE RESULTING
IN SOUTHERLY FLOW ACROSS THE COASTAL WATERS DURING THE SHORT TERM
PERIOD. THE PRESSURE GRADIENT WILL LIKELY SUPPORT WINDS IN THE 10-15
KT RANGE...WITH SOME ENHANCEMENT EACH DAY FROM THE SEA BREEZE
CIRCULATION. SEAS WILL LIKELY AVERAGE 3 FT AWAY FROM THE COAST
THURSDAY AND 3-4 FT BY FRIDAY AFTERNOON...WITH HIGHER FREQUENCY
WAVES DOMINATING THE WAVE SPECTRUM.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 2 PM WEDNESDAY...BERMUDA HIGH AND PIEDMONT TROUGH WILL
MAINTAIN SOUTH TO SOUTHWEST FLOW OVER THE WATERS THROUGH THE PERIOD.
RELATIVELY WEAK GRADIENT WILL KEEP SPEEDS IN THE 10 TO 15 KT RANGE
WITH HIGHEST VALUES IN THE AFTERNOON/EVENING. SPEEDS MAY INCREASE A
LITTLE LATE IN THE PERIOD AS COLD FRONT DROPS IN FROM THE NORTHWEST
AND PINCHES GRADIENT. SEAS OF 2 TO 4 FT WILL BE A COMBINATION OF
DOMINANT SOUTHERLY WIND WAVE AND EAST TO SOUTHEAST SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...DCH/DRH
SHORT TERM...SRP
LONG TERM...III
AVIATION...SGL
MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
753 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE
NORTHEAST THEN MOVE OFFSHORE OVER THE NEXT SEVERAL DAYS. AS THE
RIDGE LOSES ITS GRIP ACROSS THE REGION THE WINDS WILL BECOME
SOUTHERLY ALLOWING THE RETURN OF WARMER AND MORE HUMID AIR INTO THE
CAROLINAS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE AREA
MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 2 PM WEDNESDAY...HIGH PRESSURE CONTINUES TO WEDGE IN FROM THE
NORTHEAST AND MID-LEVEL CLOUD COVER CONTINUES MAINLY WEST OF
INTERSTATE 95.
THE HIGH RESOLUTION NUMERICAL MODELS ARE HAVING A DIFFICULT TIME
OF PRODUCING ANY CONVECTION AND THE 15 UTC HRRR IS SHOWING
ISOLATED CONVECTION AT 17 UTC BUT IT IS SHORT LIVED AND MAINLY
WEST OF A ELIZABETHTOWN TO ANDREWS LINE. CURRENT RADAR IS SHOWING
ONE POSSIBLE CONVECTIVE ELEMENT OVER CHESTERFIELD COUNTY. VISIBLE
SATELLITE IS SOME ENHANCED CUMULUS FIELDS OVER FLORENCE AND WESTERN
WILLIAMSBURG COUNTY.
A INTERESTING CYCLONIC FEATURE HAS BEEN OBSERVED IN THE RADAR THE
PAST HOUR OR SHOW. A FEW SHOWERS ARE WORKING THEIR WAY TOWARD THE
COAST BUT ARE SLOWLY DISSIPATING AS THEY APPROACH COAST. TODAY
WOULD BE A GOOD DAY FOR A LESS THAN 20% CHANCE. WILL CONTINUE TO
MONITOR AND MAY UP IT TO A 20% CHANCE ALONG INTERSTATE 95 AND THE
HORRY AND GEORGETOWN COAST ON THE NEXT UPDATE IF MORE SHOWERS
CONTINUE.
MOSTLY CLEAR SKIES ARE EXPECTED OVERNIGHT WITH TEMPERATURES
RANGING FROM NEAR 70 INLAND TO MID 70S ALONG THE BEACH. AS
MENTIONED IN LAST NIGHTS DISCUSSION WILL CONTINUE A MENTION OS
SHOWERS/ISOLATED THUNDERSTORMS OVER THE COASTAL WATERS WITH THE
SOUTHEAST FLOW. THEREFORE WILL STILL INCLUDE A 20 PERCENT POP FOR
THE BEACHES AROUND SUNRISE.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...THE ATMOSPHERE WILL BE TRANSITIONING BACK TO
A MORE TYPICAL SUMMERTIME PATTERN WITH HIGH PRESSURE SETTING UP OFF
THE COAST ALLOWING FOR THE RETURN OF MORE HUMID CONDITIONS. AN H5
SUBTROPICAL RIDGE WILL BECOME PINCHED FROM THE SOUTHEAST U.S.
WESTWARD TO THE LOWER MS VALLEY AND TX...WITH A STRONG SHORTWAVE
PUSHING ACROSS SOUTHEAST CANADA AND WESTWARD MOVING H5 TROFS OVER
THE GULF OF MEXICO. DON/T THINK THE AIR-MASS WILL BECOME STRONGLY
CAPPED ACROSS THE FORECAST AREA AND WITH SUFFICIENT INSTABILITY
EXPECT WIDELY SCATTERED SHOWERS/TSTMS EACH DAY. THE SEA BREEZE FRONT
WILL BE THE PRIMARY LIFTING MECHANISM...MORE-SO IN THE AFTERNOON AND
EARLY EVENING. MAX/MIN TEMPS WILL BE AT OR ABOVE CLIMO EACH PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 2 PM WEDNESDAY...ELONGATED MID LEVEL RIDGE WILL START TO BREAK
DOWN EARLY NEXT WEEK WITH LONGWAVE 5H TROUGH SETTING UP OVER THE
EAST COAST BY THE END OF THE PERIOD. THE PERIOD WILL START OFF WARM
AND RELATIVELY DRY...HIGHS IN THE LOW TO MID 90S AND LOWS IN THE LOW
TO MID 70S WITH SLIGHT CHC TO LOW CHC POP. CONVECTION IS LIKELY TO
BE DIURNAL IN NATURE AND ASSOCIATED WITH THE SEA BREEZE AND PIEDMONT
TROUGH. BREAK DOWN OF THE RIDGE AND RETREATING BERMUDA HIGH ALLOWS A
COLD FRONT TO DROP IN FROM THE NORTHWEST ON MON. MID LEVEL TROUGH
AXIS NEVER MOVES OFF THE COAST AND THE FRONT ENDS UP LAYING PARALLEL
TO THE STEERING FLOW. THIS WILL KEEP THE FRONT STALLED IN THE AREA
THROUGH WED. ABUNDANT DEEP MOISTURE IN THE PRESENCE OF THE
BOUNDARY...ALONG WITH OCCASIONAL SHORTWAVES PASSING OVERHEAD IN
SOUTHEAST FLOW WILL ELEVATE POP CHANCES FOR SECOND HALF OF THE
PERIOD. WILL KEEP POP IN CHC CAT BUT INCREASE TO 40-50 ALONG WITH
LOWERING HIGHS. LOWS WILL LIKELY REMAIN IN THE LOW TO MID 70S AS
COOLER AIR REMAINS TRAPPED NORTHWEST OF THE REGION AND CLOUD COVER
WILL LINGER. THINK COVERAGE OF PRECIP WILL DECREASE OVERNIGHT BUT
SHOWERS ARE LIKELY TO LINGER OVERNIGHT SO WILL MAINTAIN LOW CHC POP.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...EXPECT VFR THROUGH THE VALID PERIOD WITH THE EXCEPTION
OF MVFR/POSSIBLE IFR DUE TO FOG/LOW CIGS LATE OVERNIGHT INTO THE
EARLY MORNING HOURS ON THURSDAY.
LIGHT WINDS AND FEW/SCT CLOUDS WILL CONTINUE INTO THE OVERNIGHT
HOURS. GIVEN LATEST TIME-HEIGHT ANALYSIS AND FCST SOUNDINGS...ANTICIPATE
MVFR ALONG THE COAST AND POSSIBLE IFR/LIFR INLAND DUE TO FOG
DEVELOPMENT AND LOW CIGS LATE OVERNIGHT INTO THE EARLY MORNING
HOURS. AFTER DAYBREAK ON THURSDAY...CONDITIONS WILL IMPROVE TO VFR
WITH LIGHT WINDS. AS HIGH PRESSURE SHIFTS ABOUT THE AREA...WINDS
WILL BECOME SOUTHWEST BY THE AFTERNOON HOURS WITH SUSTAINED WINDS
AOB 12 KTS...BECOMING LIGHT INTO THE EVENING HOURS...WITH MID AND
HIGH CLOUDS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM WEDNESDAY...WINDS ARE NOW LIGHT FROM THE EAST AT 10 KNOTS
WITH SEAS RUNNING AROUND 2 FEET. WITH THE SOUTHEASTERLY FLOW THERE
HAS BEEN A SLIGHT INCREASE IN SHOWERS OVER THE WATER AS A SMALL
CYCLONIC FEATURE HAS BEEN OBSERVED ON RADAR THE PAST COUPLE OF
HOURS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS AS THEY PUSH TOWARDS
THE COAST.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 2 PM WEDNESDAY...HIGH PRESSURE WILL PRESIDE OFFSHORE RESULTING
IN SOUTHERLY FLOW ACROSS THE COASTAL WATERS DURING THE SHORT TERM
PERIOD. THE PRESSURE GRADIENT WILL LIKELY SUPPORT WINDS IN THE 10-15
KT RANGE...WITH SOME ENHANCEMENT EACH DAY FROM THE SEA BREEZE
CIRCULATION. SEAS WILL LIKELY AVERAGE 3 FT AWAY FROM THE COAST
THURSDAY AND 3-4 FT BY FRIDAY AFTERNOON...WITH HIGHER FREQUENCY
WAVES DOMINATING THE WAVE SPECTRUM.
LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 2 PM WEDNESDAY...BERMUDA HIGH AND PIEDMONT TROUGH WILL
MAINTAIN SOUTH TO SOUTHWEST FLOW OVER THE WATERS THROUGH THE PERIOD.
RELATIVELY WEAK GRADIENT WILL KEEP SPEEDS IN THE 10 TO 15 KT RANGE
WITH HIGHEST VALUES IN THE AFTERNOON/EVENING. SPEEDS MAY INCREASE A
LITTLE LATE IN THE PERIOD AS COLD FRONT DROPS IN FROM THE NORTHWEST
AND PINCHES GRADIENT. SEAS OF 2 TO 4 FT WILL BE A COMBINATION OF
DOMINANT SOUTHERLY WIND WAVE AND EAST TO SOUTHEAST SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DRH
SHORT TERM...SRP
LONG TERM...III
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
122 PM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE FARTHER OUT TO
SEA THIS WEEK...BUT A RIDGE AXIS WILL REMAIN ACROSS NORTH CAROLINA
THROUGH WEDNESDAY. AS WINDS GRADUALLY TURN MORE SOUTHERLY HEAT AND
HUMIDITY WILL RETURN LATE IN THE WEEK. A PIEDMONT TROUGH WILL
DEVELOP INLAND FRIDAY AND SATURDAY AHEAD OF A COLD FRONT THAT MAY
APPROACH FROM THE NORTH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...ANOTHER COOL DAY ON TAP ACROSS THE EASTERN
CAROLINAS AS CANADIAN HIGH PRESSURE DRIFTING OFFSHORE THE
MID-ATLANTIC CONTINUES ITS INFLUENCE OVER THE REGION. AN UPPER LEVEL
IMPULSE MOVING THROUGH THE EASTERN CONUS LONGWAVE TROUGH MAY BRING
SOME LIGHT RAIN SHOWERS TO THE AREA LATER THIS MORNING INTO THE AFTN.
WEAKENING COLD FRONT HAS CRUISED TO JUST SOUTH OF THE
FLORIDA-GEORGIA LINE...WITH CANADIAN HIGH PRESSURE KEEPING THE HEAT
OF THE SUMMER AT BAY. TEMPS TODAY WILL STRUGGLE AGAIN TO SEVERAL
DEGREES BELOW NORMAL FOR EARLY AUGUST...REACHING ONLY THE LOW 80S
ACROSS THE NORTHERN TIER...MID/UPR 80S FAR SOUTH. WHILE WINDS WILL
SLOWLY BECOME MORE S/SE TODAY AS HIGH PRESSURE RETREATS FURTHER
OFFSHORE...THIS CONTINUES TO ADVECT VERY DRY AIR INTO THE CWA SINCE
STREAMLINES SUGGEST CANADIAN AIR-MASS ORIGIN, AS NOTED BY PREVIOUS
FORECASTER. THIS CONTINUED DRY AIR IS IMPORTANT TO NOTE...SINCE IT
WILL HAVE CONSIDERABLE IMPACT ON PRECIP CHANCES THROUGH THIS EVE.
AN UPPER IMPULSE NOTED ON WV IMAGERY IS PRODUCING AN AREA OF LIGHT
TO MDT RAIN SHOWERS...CURRENTLY JUST WEST OF THE ILM CWA. THIS
SHORTWAVE WILL MOVE NEARLY OVERHEAD THIS AFTN...EXITING OFFSHORE BY
4PM THIS EVE. FORECAST PROFILES SUGGEST INCREASING MID-LEVEL
SATURATION FROM ELIZABETHTOWN...TO FLORENCE...AND POINTS WEST THIS
AFTN...WHILE THE COASTAL REGION REMAINS QUITE DRY. THIS POINTS TO
THE POTENTIAL FOR A PERIOD OF SHOWERS...FOCUSED MAINLY ACROSS THE
WESTERN HALF OF THE CWA...WITH PRECIP ERODING SLOWLY AS THE
SHORTWAVE TRAVERSES EASTWARD. THIS IS ALREADY EVIDENT ON
REFLECTIVITY...SO INHERITED LOW-CHC ACROSS THE NW TIER REMAINS
UNCHANGED...BUT DID EXPAND SCHC POP SE SLIGHTLY TO ACCOUNT FOR
LATEST HRRR WHICH HAS PERFORMED WELL THIS MORNING. EVEN PLACES THAT
DO NOT RECEIVE RAINFALL TODAY WILL SEE INCREASING MID LEVEL
CLOUDINESS.
TONIGHT...RENEWED DRYING WILL OCCUR WITHIN THE COLUMN...BRINGING AN
END TO ANY PRECIP CHANCES FOR THE PERIOD. LIGHT SOUTHERLY WINDS WILL
PERSIST HOWEVER...SO EVEN AS SKY CONDITIONS IMPROVE...RADIATIONAL
COOLING WILL BE SOMEWHAT INHIBITED. MINS WILL BE A DEGREE OR TWO
WARMER THAN LAST NIGHT...FALLING TO 70-73 AT THE COAST...67-70
INLAND.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE
EAST COAST THROUGH THE PERIOD. COASTAL CAROLINAS WILL BASICALLY BE
IN A DEEPER WARMER AND MOISTER RETURN FLOW ON THE WESTERN
PERIPHERY OF THE ATLANTIC RIDGE BY THE END OF THE PERIOD. THE FLOW
WILL SHIFT FROM SE ON WED TO S-SW BY FRI MORNING. ALTHOUGH
DEWPOINT TEMPS WILL BE CREEPING BACK UP TOWARD 70 ON WED...THE
ATMOSPHERIC COLUMN WILL REMAIN RELATIVELY DRY WITH PCP WATER
VALUES AROUND 1.5 INCHES. LOOKS LIKE A MINOR PERTURBATION FROM THE
WEST IN THE MID LEVEL FLOW WILL REACH THE COAST OVERNIGHT WED AND
MAY SEE SOME CLOUDS AND AN ISOLATED SHOWER OR TWO MOVING ACROSS
THE COASTAL WATERS AND POSSIBLY JUST ALONG THE COAST.
OTHERWISE...EXPECT PLENTY OF SUNSHINE FOR WED. BY THURS A DEEPER
SOUTHERLY FLOW WILL CONTINUE TO FEED MOISTURE INTO THE AREA
BRINGING PCP WATER VALUES UP TO 1.75 INCHES...BUT MID TO UPPER
RIDGE WILL NUDGE INTO THE AREA FROM THE EAST. OVERALL EXPECT CU
BUILDUP IN THE AFTERNOON AND ONLY LOCALIZED CONVECTION MAINLY
ALONG THE SEA BREEZE BOUNDARY WITH DRY AIR AND SUBSIDENCE ALOFT TO
PREVENT MORE WIDESPREAD ACTIVITY. TEMPS WILL RUN SLIGHTLY BELOW
NORMAL ON WED WITH MID 80S MOST PLACES AND WILL HEAD BACK TO
NORMAL ON THURS WITH READINGS NEAR 70 FOR LOWS AND CLOSER TO 90
FOR HIGHS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL PERSIST AROUND
ATLANTIC HIGH PRESSURE AS MID TO UPPER RIDGE BUILDS OVER THE AREA
FROM THE SOUTHEAST FRI INTO SAT. THE SOUTHERN EXTENT OF A COLD
FRONT WILL REACH THE CAROLINAS BY SATURDAY BUT WILL END UP
STALLING WITH PIEDMONT TROUGH INLAND AND SEA BREEZE BOUNDARY BEING
THE MAIN FEATURES TO FOCUS ANY CONVECTION ON BOTH FRI AND
SATURDAY. THE H5 RIDGE UP TO 595 DEM JUST OFF THE COAST FRI INTO
EARLY SAT SHOULD PROVIDE ENOUGH SUBSIDENCE TO KEEP SHOWER ACTIVITY
LIMITED TO MAINLY INLAND AREAS. BY SATURDAY THE RIDGE GETS
SUPPRESSED FARTHER SOUTH AS MID TO UPPER TROUGH BEGINS TO DIG DOWN
THE EAST COAST WITH SFC TROUGH/FRONT SHIFTING SOUTHEAST AND CLOSER
TO THE COAST. BY LATE SUNDAY THROUGH TUESDAY...A MUCH DEEPER
COLUMN OF MOISTURE WILL BE PRESENT WITH PCP WATER VALUES UP ABOVE
2 INCHES. OVERALL EXPECT INCREASING CHC OF MORE WIDESPREAD
CONVECTION INTO EARLY NEXT WEEK WITH GREATER INSTABILITY AND
MOISTURE IN THE ATMOSPHERE AS DECENT UPPER LEVEL SUPPORT.
DEWPOINT TEMPS WILL BE BACK UP IN THE 70S WITH OVERNIGHT LOWS
IN THE MID 70S AND DAY TIME HIGHS REACHING INTO THE 90S. CLOUDS
AND PCP MAY KEEP VALUES SLIGHTLY LOWER EACH AFTERNOON INTO EARLY
NEXT WEEK.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AS OF 18Z...STRATIFORM PRECIP LOOKS TO HANG IN THERE THROUGH MUCH OF
THE AFTERNOON...AFFECTING MAINLY FLO AND LBT. VISIBILITIES WILL
REMAIN VFR AS WELL AS CEILINGS IN THE PRECIP. MAINLY A MID CLOUD
CEILING THROUGHOUT THE REGION THROUGH THE AFTERNOON HOURS WITH A
VARIABLE WIND...STRONGEST...AND FROM THE SOUTHEAST...NEAR THE COAST.
MUCH OF THE CLOUDS DISSIPATE THROUGH THE OVERNIGHT HOURS. SOME MVFR
FOG IS POSSIBLE AT THE INLAND TERMINALS AS THE PRECIP THIS AFTERNOON
SHOULD MOISTEN UP THE LOWER LAYERS JUST ENOUGH. WEDNESDAY...BECOMING
VFR WITH MAINLY SCATTERED SKIES AND A CONTINUED SOUTHEAST
WIND...MAINLY LESS THAN 10 KTS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SUNDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...CANADIAN HIGH PRESSURE JUST OFF THE
MID-ATLANTIC COAST WILL CONTINUE TO PUSH SLOWLY AWAY FROM SHORE
THROUGH TONIGHT. WHILE THIS OCCURS...A RIDGE AXIS WILL CONTINUE TO
EXTEND BACK TOWARDS THE EASTERN CAROLINAS...KEEPING THE PRESSURE
GRADIENT LIGHT AND WINDS E/SE AT AROUND 10 KTS. SEAS AT THE LOCAL
BUOYS ARE CURRENTLY ALL 2 FT OR LESS...AND THIS WILL PERSIST THROUGH
THE PERIOD WITH LITTLE CHANGE. WAVES WILL BE FORMED BY A CONTINUED
4-SEC E/SE WIND CHOP AND 10 SEC SE GROUND SWELL.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...RETURN FLOW AROUND ATLANTIC RIDGE OF HIGH
PRESSURE WILL PERSIST THROUGH THE PERIOD. THE FLOW WILL VEER
AROUND FROM SOUTHEAST ON WED BECOMING MORE S-SW ON THURS. THE
WINDS WILL REMAIN AROUND 10 KTS SPIKING UP A BIT EACH AFTERNOON IN
THE SEA BREEZE. THE PERSISTENT ON SHORE PUSH WILL KEEP SEAS AROUND
2 TO 3 FT WITH SHORTER PERIOD WIND WAVES MIXING WITH A LONGER
PERIOD 9 SECOND SE SWELL.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT A SOUTH TO SOUTHWEST FLOW TO
CONTINUE THROUGH THE PERIOD AROUND ATLANTIC HIGH. THE WINDS WILL
VEER SLIGHTLY MORE INTO THE WEEKEND AS PIEDMONT TROUGH BECOMES
MORE PRONOUNCED AND COLD FRONT MOVES INTO THE CAROLINAS FROM THE
NORTHWEST OVER THE WEEKEND. THE GRADIENT WILL TIGHTEN BETWEEN INLAND
TROUGH/FRONT AND HIGH PRESSURE OFF SHORE TO PRODUCE WIND 10 TO 15 KTS
THROUGH THE PERIOD. THE INCREASED SOUTHERLY PUSH WILL PRODUCE A
RISE IN SEAS UP CLOSER TO 3 FT THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43/17
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1017 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE FARTHER OUT TO
SEA THIS WEEK...BUT A RIDGE AXIS WILL REMAIN ACROSS NORTH CAROLINA
THROUGH WEDNESDAY. AS WINDS GRADUALLY TURN MORE SOUTHERLY HEAT AND
HUMIDITY WILL RETURN LATE IN THE WEEK. A PIEDMONT TROUGH WILL
DEVELOP INLAND FRIDAY AND SATURDAY AHEAD OF A COLD FRONT THAT MAY
APPROACH FROM THE NORTH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...ANOTHER COOL DAY ON TAP ACROSS THE EASTERN
CAROLINAS AS CANADIAN HIGH PRESSURE DRIFTING OFFSHORE THE
MID-ATLANTIC CONTINUES ITS INFLUENCE OVER THE REGION. AN UPPER LEVEL
IMPULSE MOVING THROUGH THE EASTERN CONUS LONGWAVE TROUGH MAY BRING
SOME LIGHT RAIN SHOWERS TO THE AREA LATER THIS MORNING INTO THE AFTN.
WEAKENING COLD FRONT HAS CRUISED TO JUST SOUTH OF THE
FLORIDA-GEORGIA LINE...WITH CANADIAN HIGH PRESSURE KEEPING THE HEAT
OF THE SUMMER AT BAY. TEMPS TODAY WILL STRUGGLE AGAIN TO SEVERAL
DEGREES BELOW NORMAL FOR EARLY AUGUST...REACHING ONLY THE LOW 80S
ACROSS THE NORTHERN TIER...MID/UPR 80S FAR SOUTH. WHILE WINDS WILL
SLOWLY BECOME MORE S/SE TODAY AS HIGH PRESSURE RETREATS FURTHER
OFFSHORE...THIS CONTINUES TO ADVECT VERY DRY AIR INTO THE CWA SINCE
STREAMLINES SUGGEST CANADIAN AIR-MASS ORIGIN, AS NOTED BY PREVIOUS
FORECASTER. THIS CONTINUED DRY AIR IS IMPORTANT TO NOTE...SINCE IT
WILL HAVE CONSIDERABLE IMPACT ON PRECIP CHANCES THROUGH THIS EVE.
AN UPPER IMPULSE NOTED ON WV IMAGERY IS PRODUCING AN AREA OF LIGHT
TO MDT RAIN SHOWERS...CURRENTLY JUST WEST OF THE ILM CWA. THIS
SHORTWAVE WILL MOVE NEARLY OVERHEAD THIS AFTN...EXITING OFFSHORE BY
4PM THIS EVE. FORECAST PROFILES SUGGEST INCREASING MID-LEVEL
SATURATION FROM ELIZABETHTOWN...TO FLORENCE...AND POINTS WEST THIS
AFTN...WHILE THE COASTAL REGION REMAINS QUITE DRY. THIS POINTS TO
THE POTENTIAL FOR A PERIOD OF SHOWERS...FOCUSED MAINLY ACROSS THE
WESTERN HALF OF THE CWA...WITH PRECIP ERODING SLOWLY AS THE
SHORTWAVE TRAVERSES EASTWARD. THIS IS ALREADY EVIDENT ON
REFLECTIVITY...SO INHERITED LOW-CHC ACROSS THE NW TIER REMAINS
UNCHANGED...BUT DID EXPAND SCHC POP SE SLIGHTLY TO ACCOUNT FOR
LATEST HRRR WHICH HAS PERFORMED WELL THIS MORNING. EVEN PLACES THAT
DO NOT RECEIVE RAINFALL TODAY WILL SEE INCREASING MID LEVEL
CLOUDINESS.
TONIGHT...RENEWED DRYING WILL OCCUR WITHIN THE COLUMN...BRINGING AN
END TO ANY PRECIP CHANCES FOR THE PERIOD. LIGHT SOUTHERLY WINDS WILL
PERSIST HOWEVER...SO EVEN AS SKY CONDITIONS IMPROVE...RADIATIONAL
COOLING WILL BE SOMEWHAT INHIBITED. MINS WILL BE A DEGREE OR TWO
WARMER THAN LAST NIGHT...FALLING TO 70-73 AT THE COAST...67-70
INLAND.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE
EAST COAST THROUGH THE PERIOD. COASTAL CAROLINAS WILL BASICALLY BE
IN A DEEPER WARMER AND MOISTER RETURN FLOW ON THE WESTERN
PERIPHERY OF THE ATLANTIC RIDGE BY THE END OF THE PERIOD. THE FLOW
WILL SHIFT FROM SE ON WED TO S-SW BY FRI MORNING. ALTHOUGH
DEWPOINT TEMPS WILL BE CREEPING BACK UP TOWARD 70 ON WED...THE
ATMOSPHERIC COLUMN WILL REMAIN RELATIVELY DRY WITH PCP WATER
VALUES AROUND 1.5 INCHES. LOOKS LIKE A MINOR PERTURBATION FROM THE
WEST IN THE MID LEVEL FLOW WILL REACH THE COAST OVERNIGHT WED AND
MAY SEE SOME CLOUDS AND AN ISOLATED SHOWER OR TWO MOVING ACROSS
THE COASTAL WATERS AND POSSIBLY JUST ALONG THE COAST.
OTHERWISE...EXPECT PLENTY OF SUNSHINE FOR WED. BY THURS A DEEPER
SOUTHERLY FLOW WILL CONTINUE TO FEED MOISTURE INTO THE AREA
BRINGING PCP WATER VALUES UP TO 1.75 INCHES...BUT MID TO UPPER
RIDGE WILL NUDGE INTO THE AREA FROM THE EAST. OVERALL EXPECT CU
BUILDUP IN THE AFTERNOON AND ONLY LOCALIZED CONVECTION MAINLY
ALONG THE SEA BREEZE BOUNDARY WITH DRY AIR AND SUBSIDENCE ALOFT TO
PREVENT MORE WIDESPREAD ACTIVITY. TEMPS WILL RUN SLIGHTLY BELOW
NORMAL ON WED WITH MID 80S MOST PLACES AND WILL HEAD BACK TO
NORMAL ON THURS WITH READINGS NEAR 70 FOR LOWS AND CLOSER TO 90
FOR HIGHS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL PERSIST AROUND
ATLANTIC HIGH PRESSURE AS MID TO UPPER RIDGE BUILDS OVER THE AREA
FROM THE SOUTHEAST FRI INTO SAT. THE SOUTHERN EXTENT OF A COLD
FRONT WILL REACH THE CAROLINAS BY SATURDAY BUT WILL END UP
STALLING WITH PIEDMONT TROUGH INLAND AND SEA BREEZE BOUNDARY BEING
THE MAIN FEATURES TO FOCUS ANY CONVECTION ON BOTH FRI AND
SATURDAY. THE H5 RIDGE UP TO 595 DEM JUST OFF THE COAST FRI INTO
EARLY SAT SHOULD PROVIDE ENOUGH SUBSIDENCE TO KEEP SHOWER ACTIVITY
LIMITED TO MAINLY INLAND AREAS. BY SATURDAY THE RIDGE GETS
SUPPRESSED FARTHER SOUTH AS MID TO UPPER TROUGH BEGINS TO DIG DOWN
THE EAST COAST WITH SFC TROUGH/FRONT SHIFTING SOUTHEAST AND CLOSER
TO THE COAST. BY LATE SUNDAY THROUGH TUESDAY...A MUCH DEEPER
COLUMN OF MOISTURE WILL BE PRESENT WITH PCP WATER VALUES UP ABOVE
2 INCHES. OVERALL EXPECT INCREASING CHC OF MORE WIDESPREAD
CONVECTION INTO EARLY NEXT WEEK WITH GREATER INSTABILITY AND
MOISTURE IN THE ATMOSPHERE AS DECENT UPPER LEVEL SUPPORT.
DEWPOINT TEMPS WILL BE BACK UP IN THE 70S WITH OVERNIGHT LOWS
IN THE MID 70S AND DAY TIME HIGHS REACHING INTO THE 90S. CLOUDS
AND PCP MAY KEEP VALUES SLIGHTLY LOWER EACH AFTERNOON INTO EARLY
NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...A COUPLE OF WEAK DISTURBANCES COMING OVER THE MOUNTAINS
WILL GIVE THE NORTHWESTERN PORTION OF THE CWA A CHANCE FOR SHOWERS
THROUGH THE MORNING HOURS. MUCH OF THE PRECIPITATION WILL COME OUT
OF MID CLOUD AND WILL LIKELY STAY VIRGA. WILL KEEP VCSH IN THE LBT
TAF...OTHERWISE PRECIP FREE FOR THE REMAINDER OF THE REGION. MAINLY
A MID CLOUD CEILING THROUGHOUT THE REGION THROUGH THE AFTERNOON
HOURS WITH A SOUTHEAST WIND...STRONGEST NEAR THE COAST. MUCH OF THE
CLOUDS DISSIPATE THROUGH THE OVERNIGHT HOURS...BUT PROBABLY TOO DRY
AT THE SURFACE TO ADD FOG.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SATURDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...CANADIAN HIGH PRESSURE JUST OFF THE
MID-ATLANTIC COAST WILL CONTINUE TO PUSH SLOWLY AWAY FROM SHORE
THROUGH TONIGHT. WHILE THIS OCCURS...A RIDGE AXIS WILL CONTINUE TO
EXTEND BACK TOWARDS THE EASTERN CAROLINAS...KEEPING THE PRESSURE
GRADIENT LIGHT AND WINDS E/SE AT AROUND 10 KTS. SEAS AT THE LOCAL
BUOYS ARE CURRENTLY ALL 2 FT OR LESS...AND THIS WILL PERSIST THROUGH
THE PERIOD WITH LITTLE CHANGE. WAVES WILL BE FORMED BY A CONTINUED
4-SEC E/SE WIND CHOP AND 10 SEC SE GROUND SWELL.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...RETURN FLOW AROUND ATLANTIC RIDGE OF HIGH
PRESSURE WILL PERSIST THROUGH THE PERIOD. THE FLOW WILL VEER
AROUND FROM SOUTHEAST ON WED BECOMING MORE S-SW ON THURS. THE
WINDS WILL REMAIN AROUND 10 KTS SPIKING UP A BIT EACH AFTERNOON IN
THE SEA BREEZE. THE PERSISTENT ON SHORE PUSH WILL KEEP SEAS AROUND
2 TO 3 FT WITH SHORTER PERIOD WIND WAVES MIXING WITH A LONGER
PERIOD 9 SECOND SE SWELL.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT A SOUTH TO SOUTHWEST FLOW TO
CONTINUE THROUGH THE PERIOD AROUND ATLANTIC HIGH. THE WINDS WILL
VEER SLIGHTLY MORE INTO THE WEEKEND AS PIEDMONT TROUGH BECOMES
MORE PRONOUNCED AND COLD FRONT MOVES INTO THE CAROLINAS FROM THE
NORTHWEST OVER THE WEEKEND. THE GRADIENT WILL TIGHTEN BETWEEN INLAND
TROUGH/FRONT AND HIGH PRESSURE OFF SHORE TO PRODUCE WIND 10 TO 15 KTS
THROUGH THE PERIOD. THE INCREASED SOUTHERLY PUSH WILL PRODUCE A
RISE IN SEAS UP CLOSER TO 3 FT THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
650 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE FARTHER OUT TO
SEA THIS WEEK...BUT A RIDGE AXIS WILL REMAIN ACROSS NORTH CAROLINA
THROUGH WEDNESDAY. AS WINDS GRADUALLY TURN MORE SOUTHERLY HEAT AND
HUMIDITY WILL RETURN LATE IN THE WEEK. A PIEDMONT TROUGH WILL
DEVELOP INLAND FRIDAY AND SATURDAY AHEAD OF A COLD FRONT THAT MAY
APPROACH FROM THE NORTH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM TUESDAY...TWEAKS TO CLOUDS AND POPS ARE THE MAIN FOCUS
OF THIS EARLY MORNING UPDATE...INCORPORATING THE LATEST HRRR MODEL
WHICH SEEMS TO HAVE INITIALIZED FAIRLY WELL. MEASURABLE RAIN CHANCES
ARE HIGHEST TODAY IN THE AREA FROM BENNETTSVILLE THROUGH LUMBERTON
AND ELIZABETHTOWN. THE 00Z ECMWF MOS TEMPERATURES CAME IN VERY CLOSE
TO MY FORECAST HIGHS SO NO SIGNIFICANT CHANGES ARE PLANNED THERE.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
UNSEASONABLY DRY AIR AT THE SURFACE IS BEING PROVIDED BY EASTERLY
FLOW AROUND HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST.
ALTHOUGH AN EAST WIND IS NORMALLY QUITE HUMID... LOOKING BACK ALONG
THE STREAMLINES REVEALS THIS AIR HAS CANADIAN ORIGINS JUST A FEW
DAYS AGO. THE COLD FRONT THAT PUSHED ACROSS THE CAROLINAS TWO DAYS
AGO IS STALLED NEAR THE GEORGIA/FLORIDA STATE LINE AND SHOULD WEAKEN
TODAY.
IN THE UPPER LEVELS A LONGWAVE TROUGH REMAINS ACROSS EASTERN NORTH
AMERICA. THERE ARE MULTIPLE SHORTWAVES EMBEDDED WITHIN THE REGION OF
CYCLONIC FLOW ALOFT. THE ONE EXPECTED TO HAVE THE MOST IMPACT ON OUR
WEATHER TODAY IS CURRENTLY OVER THE SOUTHERN APPALACHIANS AND IS
HELPING SUSTAIN SHOWERS AND T-STORMS EARLY THIS MORNING ACROSS THE
WESTERN AND CENTRAL CAROLINAS.
THERE ARE COMPETING FACTORS AT WORK REGARDING HOW HIGH PRECIPITATION
CHANCES WILL BECOME HERE IN THE EASTERN CAROLINAS LATER TODAY. THE
UPPER LEVEL DISTURBANCE WILL MOVE EAST OUT OF THE MOUNTAINS AND
OVERHEAD BETWEEN 11AM AND 2 PM. THERE IS INCREASING MID LEVEL
MOISTURE AND SOME COOLING ALOFT THAT WILL HELP ERODE THE MID-LEVEL
CAPPING OBSERVED ON BOTH THE 00Z MHX AND CHS SOUNDINGS. NEGATIVE
FACTORS WORKING AGAINST PRECIPITATION INCLUDE RESIDUAL DRY AIR BELOW
850 MB THAT WILL KEEP SURFACE-BASED INSTABILITY VERY LOW...AND A JET
STREAK AT 200 MB CENTERED OVER OHIO AND WEST VIRGINIA WHICH PLACES
THE CAROLINAS IN THE RIGHT-EXIT REGION...TYPICALLY ASSOCIATED WITH
UPPER LEVEL CONVERGENCE AND LOWER-TROPOSPHERIC SINKING MOTION. THE
COAST CERTAINLY WILL HAVE THE SMALLEST PRECIPITATION POTENTIAL TODAY
GIVEN OVERWHELMING DRY AIR. I AM FORECASTING ONLY PERIODS OF
CLOUDINESS TO PASS OVERHEAD HERE TODAY. ALONG THE INTERSTATE 95
CORRIDOR (BUT PARTICULARLY AROUND LUMBERTON) THERE ARE INCREASING
CHANCES FOR SHOWERS FORECAST...MAINLY FROM MID MORNING THROUGH EARLY
AFTERNOON AS THE UPPER DISTURBANCE CROSSES THE AREA. DESPITE WARMING
TEMPERATURES IN THE AFTERNOON WITH SOME SUNSHINE...NVA AND INCREASED
SUBSIDENT MOTION BEHIND THE SHORTWAVE SHOULD LEAD TO DIMINISHING
RAIN CHANCES.
THE 00Z GFS IS MUCH MORE BULLISH WITH RAIN CHANCES THAN THE 00Z
NAM...AND WITH ITS ADDITIONAL RAINFALL THE GFS HAS MUCH COOLER
TEMPERATURES FORECAST TODAY COMPARED TO THE NAM. GIVEN CURRENT RADAR
RETURNS ALONG I-85 FROM CHARLOTTE THROUGH GREENSBORO THE GFS IS
PROBABLY CORRECT WITH COVERAGE BUT MAY HAVE PLACED ITS QPF MAXIMUM
TOO FAR SOUTH. MY FORECAST IS FOR 20-30 PERCENT COVERAGE OF SHOWERS
ACROSS DARLINGTON-FLORENCE-DILLON-LUMBERTON-ELIZABETHTOWN...WITH
ONLY A 5-10 PERCENT CHANCE AT THE COAST. HIGHS SHOULD RANGE FROM THE
UPPER 80S FROM FLORENCE AND MARION INTO KINGSTREE...WITH MID 80S
ELSEWHERE.
ALTHOUGH AREAS OF MID LEVEL CLOUDINESS WILL HANG AROUND THROUGH
TONIGHT PRECIPITATION CHANCES SHOULD BE TOO LOW FOR MENTION IN THE
FORECAST. TEMPERATURES WILL MODERATE A LITTLE WITH THE CONTINUING
ONSHORE FLOW...WITH LOWS IN THE UPPER 60S FORECAST INLAND AND LOWER
70S AT THE BEACHES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE
EAST COAST THROUGH THE PERIOD. COASTAL CAROLINAS WILL BASICALLY BE
IN A DEEPER WARMER AND MOISTER RETURN FLOW ON THE WESTERN
PERIPHERY OF THE ATLANTIC RIDGE BY THE END OF THE PERIOD. THE FLOW
WILL SHIFT FROM SE ON WED TO S-SW BY FRI MORNING. ALTHOUGH
DEWPOINT TEMPS WILL BE CREEPING BACK UP TOWARD 70 ON WED...THE
ATMOSPHERIC COLUMN WILL REMAIN RELATIVELY DRY WITH PCP WATER
VALUES AROUND 1.5 INCHES. LOOKS LIKE A MINOR PERTURBATION FROM THE
WEST IN THE MID LEVEL FLOW WILL REACH THE COAST OVERNIGHT WED AND
MAY SEE SOME CLOUDS AND AN ISOLATED SHOWER OR TWO MOVING ACROSS
THE COASTAL WATERS AND POSSIBLY JUST ALONG THE COAST.
OTHERWISE...EXPECT PLENTY OF SUNSHINE FOR WED. BY THURS A DEEPER
SOUTHERLY FLOW WILL CONTINUE TO FEED MOISTURE INTO THE AREA
BRINGING PCP WATER VALUES UP TO 1.75 INCHES...BUT MID TO UPPER
RIDGE WILL NUDGE INTO THE AREA FROM THE EAST. OVERALL EXPECT CU
BUILDUP IN THE AFTERNOON AND ONLY LOCALIZED CONVECTION MAINLY
ALONG THE SEA BREEZE BOUNDARY WITH DRY AIR AND SUBSIDENCE ALOFT TO
PREVENT MORE WIDESPREAD ACTIVITY. TEMPS WILL RUN SLIGHTLY BELOW
NORMAL ON WED WITH MID 80S MOST PLACES AND WILL HEAD BACK TO
NORMAL ON THURS WITH READINGS NEAR 70 FOR LOWS AND CLOSER TO 90
FOR HIGHS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL PERSIST AROUND
ATLANTIC HIGH PRESSURE AS MID TO UPPER RIDGE BUILDS OVER THE AREA
FROM THE SOUTHEAST FRI INTO SAT. THE SOUTHERN EXTENT OF A COLD
FRONT WILL REACH THE CAROLINAS BY SATURDAY BUT WILL END UP
STALLING WITH PIEDMONT TROUGH INLAND AND SEA BREEZE BOUNDARY BEING
THE MAIN FEATURES TO FOCUS ANY CONVECTION ON BOTH FRI AND
SATURDAY. THE H5 RIDGE UP TO 595 DEM JUST OFF THE COAST FRI INTO
EARLY SAT SHOULD PROVIDE ENOUGH SUBSIDENCE TO KEEP SHOWER ACTIVITY
LIMITED TO MAINLY INLAND AREAS. BY SATURDAY THE RIDGE GETS
SUPPRESSED FARTHER SOUTH AS MID TO UPPER TROUGH BEGINS TO DIG DOWN
THE EAST COAST WITH SFC TROUGH/FRONT SHIFTING SOUTHEAST AND CLOSER
TO THE COAST. BY LATE SUNDAY THROUGH TUESDAY...A MUCH DEEPER
COLUMN OF MOISTURE WILL BE PRESENT WITH PCP WATER VALUES UP ABOVE
2 INCHES. OVERALL EXPECT INCREASING CHC OF MORE WIDESPREAD
CONVECTION INTO EARLY NEXT WEEK WITH GREATER INSTABILITY AND
MOISTURE IN THE ATMOSPHERE AS DECENT UPPER LEVEL SUPPORT.
DEWPOINT TEMPS WILL BE BACK UP IN THE 70S WITH OVERNIGHT LOWS
IN THE MID 70S AND DAY TIME HIGHS REACHING INTO THE 90S. CLOUDS
AND PCP MAY KEEP VALUES SLIGHTLY LOWER EACH AFTERNOON INTO EARLY
NEXT WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...A COUPLE OF WEAK DISTURBANCES COMING OVER THE MOUNTAINS
WILL GIVE THE NORTHWESTERN PORTION OF THE CWA A CHANCE FOR SHOWERS
THROUGH THE MORNING HOURS. MUCH OF THE PRECIPITATION WILL COME OUT
OF MID CLOUD AND WILL LIKELY STAY VIRGA. WILL KEEP VCSH IN THE LBT
TAF...OTHERWISE PRECIP FREE FOR THE REMAINDER OF THE REGION. MAINLY
A MID CLOUD CEILING THROUGHOUT THE REGION THROUGH THE AFTERNOON
HOURS WITH A SOUTHEAST WIND...STRONGEST NEAR THE COAST. MUCH OF THE
CLOUDS DISSIPATE THROUGH THE OVERNIGHT HOURS...BUT PROBABLY TOO DRY
AT THE SURFACE TO ADD FOG.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SATURDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 630 AM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
CANADIAN HIGH PRESSURE CENTERED OFF THE NEW JERSEY COAST IS
EXTENDING A SURFACE RIDGE AXIS SOUTHWESTWARD INTO EASTERN NORTH
CAROLINA AND CENTRAL SOUTH CAROLINA. ALTHOUGH THE MAIN AREA OF HIGH
PRESSURE WILL MOVE FARTHER OFFSHORE TONIGHT THE RIDGE AXIS WILL
REMAIN IN PLACE. THIS SHOULD KEEP OUR WINDS FROM VEERING AROUND TO
THE SOUTH AS NORMALLY OCCURS WITH A DEPARTING EAST COAST HIGH. EAST
TO SOUTHEAST WINDS 10-15 KNOTS THIS MORNING WILL DIMINISH TO AROUND
10 KNOTS FOR THIS AFTERNOON AND TONIGHT. ALTHOUGH THERE WILL BE AN
INCREASE IN CLOUD COVER THIS MORNING...IT APPEARS SHOWER CHANCES
WILL REMAIN CONFINED TO INTERIOR SECTIONS OF THE CAROLINAS. SEAS
CURRENTLY AVERAGE 2-3 FT AT THE BUOYS WITH SHORT WIND-DRIVEN
PERIODS. LITTLE CHANGE IS FORECAST INTO TONIGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...RETURN FLOW AROUND ATLANTIC RIDGE OF HIGH
PRESSURE WILL PERSIST THROUGH THE PERIOD. THE FLOW WILL VEER
AROUND FROM SOUTHEAST ON WED BECOMING MORE S-SW ON THURS. THE
WINDS WILL REMAIN AROUND 10 KTS SPIKING UP A BIT EACH AFTERNOON IN
THE SEA BREEZE. THE PERSISTENT ON SHORE PUSH WILL KEEP SEAS AROUND
2 TO 3 FT WITH SHORTER PERIOD WIND WAVES MIXING WITH A LONGER
PERIOD 9 SECOND SE SWELL.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT A SOUTH TO SOUTHWEST FLOW TO
CONTINUE THROUGH THE PERIOD AROUND ATLANTIC HIGH. THE WINDS WILL
VEER SLIGHTLY MORE INTO THE WEEKEND AS PIEDMONT TROUGH BECOMES
MORE PRONOUNCED AND COLD FRONT MOVES INTO THE CAROLINAS FROM THE
NORTHWEST OVER THE WEEKEND. THE GRADIENT WILL TIGHTEN BETWEEN INLAND
TROUGH/FRONT AND HIGH PRESSURE OFF SHORE TO PRODUCE WIND 10 TO 15 KTS
THROUGH THE PERIOD. THE INCREASED SOUTHERLY PUSH WILL PRODUCE A
RISE IN SEAS UP CLOSER TO 3 FT THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
641 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE OFF THE MID-ATLANTIC COAST WILL MOVE FARTHER OUT TO
SEA THIS WEEK...BUT A RIDGE AXIS WILL REMAIN ACROSS NORTH CAROLINA
THROUGH WEDNESDAY. AS WINDS GRADUALLY TURN MORE SOUTHERLY HEAT AND
HUMIDITY WILL RETURN LATE IN THE WEEK. A PIEDMONT TROUGH WILL
DEVELOP INLAND FRIDAY AND SATURDAY AHEAD OF A COLD FRONT THAT MAY
APPROACH FROM THE NORTH EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 645 AM TUESDAY...TWEAKS TO CLOUDS AND POPS ARE THE MAIN FOCUS
OF THIS EARLY MORNING UPDATE...INCORPORATING THE LATEST HRRR MODEL
WHICH SEEMS TO HAVE INITIALIZED FAIRLY WELL. MEASURABLE RAIN CHANCES
ARE HIGHEST TODAY IN THE AREA FROM BENNETTSVILLE THROUGH LUMBERTON
AND ELIZABETHTOWN. THE 00Z ECMWF MOS TEMPERATURES CAME IN VERY CLOSE
TO MY FORECAST HIGHS SO NO SIGNIFICANT CHANGES ARE PLANNED THERE.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
UNSEASONABLY DRY AIR AT THE SURFACE IS BEING PROVIDED BY EASTERLY
FLOW AROUND HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST.
ALTHOUGH AN EAST WIND IS NORMALLY QUITE HUMID... LOOKING BACK ALONG
THE STREAMLINES REVEALS THIS AIR HAS CANADIAN ORIGINS JUST A FEW
DAYS AGO. THE COLD FRONT THAT PUSHED ACROSS THE CAROLINAS TWO DAYS
AGO IS STALLED NEAR THE GEORGIA/FLORIDA STATE LINE AND SHOULD WEAKEN
TODAY.
IN THE UPPER LEVELS A LONGWAVE TROUGH REMAINS ACROSS EASTERN NORTH
AMERICA. THERE ARE MULTIPLE SHORTWAVES EMBEDDED WITHIN THE REGION OF
CYCLONIC FLOW ALOFT. THE ONE EXPECTED TO HAVE THE MOST IMPACT ON OUR
WEATHER TODAY IS CURRENTLY OVER THE SOUTHERN APPALACHIANS AND IS
HELPING SUSTAIN SHOWERS AND T-STORMS EARLY THIS MORNING ACROSS THE
WESTERN AND CENTRAL CAROLINAS.
THERE ARE COMPETING FACTORS AT WORK REGARDING HOW HIGH PRECIPITATION
CHANCES WILL BECOME HERE IN THE EASTERN CAROLINAS LATER TODAY. THE
UPPER LEVEL DISTURBANCE WILL MOVE EAST OUT OF THE MOUNTAINS AND
OVERHEAD BETWEEN 11AM AND 2 PM. THERE IS INCREASING MID LEVEL
MOISTURE AND SOME COOLING ALOFT THAT WILL HELP ERODE THE MID-LEVEL
CAPPING OBSERVED ON BOTH THE 00Z MHX AND CHS SOUNDINGS. NEGATIVE
FACTORS WORKING AGAINST PRECIPITATION INCLUDE RESIDUAL DRY AIR BELOW
850 MB THAT WILL KEEP SURFACE-BASED INSTABILITY VERY LOW...AND A JET
STREAK AT 200 MB CENTERED OVER OHIO AND WEST VIRGINIA WHICH PLACES
THE CAROLINAS IN THE RIGHT-EXIT REGION...TYPICALLY ASSOCIATED WITH
UPPER LEVEL CONVERGENCE AND LOWER-TROPOSPHERIC SINKING MOTION. THE
COAST CERTAINLY WILL HAVE THE SMALLEST PRECIPITATION POTENTIAL TODAY
GIVEN OVERWHELMING DRY AIR. I AM FORECASTING ONLY PERIODS OF
CLOUDINESS TO PASS OVERHEAD HERE TODAY. ALONG THE INTERSTATE 95
CORRIDOR (BUT PARTICULARLY AROUND LUMBERTON) THERE ARE INCREASING
CHANCES FOR SHOWERS FORECAST...MAINLY FROM MID MORNING THROUGH EARLY
AFTERNOON AS THE UPPER DISTURBANCE CROSSES THE AREA. DESPITE WARMING
TEMPERATURES IN THE AFTERNOON WITH SOME SUNSHINE...NVA AND INCREASED
SUBSIDENT MOTION BEHIND THE SHORTWAVE SHOULD LEAD TO DIMINISHING
RAIN CHANCES.
THE 00Z GFS IS MUCH MORE BULLISH WITH RAIN CHANCES THAN THE 00Z
NAM...AND WITH ITS ADDITIONAL RAINFALL THE GFS HAS MUCH COOLER
TEMPERATURES FORECAST TODAY COMPARED TO THE NAM. GIVEN CURRENT RADAR
RETURNS ALONG I-85 FROM CHARLOTTE THROUGH GREENSBORO THE GFS IS
PROBABLY CORRECT WITH COVERAGE BUT MAY HAVE PLACED ITS QPF MAXIMUM
TOO FAR SOUTH. MY FORECAST IS FOR 20-30 PERCENT COVERAGE OF SHOWERS
ACROSS DARLINGTON-FLORENCE-DILLON-LUMBERTON-ELIZABETHTOWN...WITH
ONLY A 5-10 PERCENT CHANCE AT THE COAST. HIGHS SHOULD RANGE FROM THE
UPPER 80S FROM FLORENCE AND MARION INTO KINGSTREE...WITH MID 80S
ELSEWHERE.
ALTHOUGH AREAS OF MID LEVEL CLOUDINESS WILL HANG AROUND THROUGH
TONIGHT PRECIPITATION CHANCES SHOULD BE TOO LOW FOR MENTION IN THE
FORECAST. TEMPERATURES WILL MODERATE A LITTLE WITH THE CONTINUING
ONSHORE FLOW...WITH LOWS IN THE UPPER 60S FORECAST INLAND AND LOWER
70S AT THE BEACHES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...HIGH PRESSURE WILL SHIFT FARTHER OFF THE
EAST COAST THROUGH THE PERIOD. COASTAL CAROLINAS WILL BASICALLY BE
IN A DEEPER WARMER AND MOISTER RETURN FLOW ON THE WESTERN
PERIPHERY OF THE ATLANTIC RIDGE BY THE END OF THE PERIOD. THE FLOW
WILL SHIFT FROM SE ON WED TO S-SW BY FRI MORNING. ALTHOUGH
DEWPOINT TEMPS WILL BE CREEPING BACK UP TOWARD 70 ON WED...THE
ATMOSPHERIC COLUMN WILL REMAIN RELATIVELY DRY WITH PCP WATER
VALUES AROUND 1.5 INCHES. LOOKS LIKE A MINOR PERTURBATION FROM THE
WEST IN THE MID LEVEL FLOW WILL REACH THE COAST OVERNIGHT WED AND
MAY SEE SOME CLOUDS AND AN ISOLATED SHOWER OR TWO MOVING ACROSS
THE COASTAL WATERS AND POSSIBLY JUST ALONG THE COAST.
OTHERWISE...EXPECT PLENTY OF SUNSHINE FOR WED. BY THURS A DEEPER
SOUTHERLY FLOW WILL CONTINUE TO FEED MOISTURE INTO THE AREA
BRINGING PCP WATER VALUES UP TO 1.75 INCHES...BUT MID TO UPPER
RIDGE WILL NUDGE INTO THE AREA FROM THE EAST. OVERALL EXPECT CU
BUILDUP IN THE AFTERNOON AND ONLY LOCALIZED CONVECTION MAINLY
ALONG THE SEA BREEZE BOUNDARY WITH DRY AIR AND SUBSIDENCE ALOFT TO
PREVENT MORE WIDESPREAD ACTIVITY. TEMPS WILL RUN SLIGHTLY BELOW
NORMAL ON WED WITH MID 80S MOST PLACES AND WILL HEAD BACK TO
NORMAL ON THURS WITH READINGS NEAR 70 FOR LOWS AND CLOSER TO 90
FOR HIGHS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERLY RETURN FLOW WILL PERSIST AROUND
ATLANTIC HIGH PRESSURE AS MID TO UPPER RIDGE BUILDS OVER THE AREA
FROM THE SOUTHEAST FRI INTO SAT. THE SOUTHERN EXTENT OF A COLD
FRONT WILL REACH THE CAROLINAS BY SATURDAY BUT WILL END UP
STALLING WITH PIEDMONT TROUGH INLAND AND SEA BREEZE BOUNDARY BEING
THE MAIN FEATURES TO FOCUS ANY CONVECTION ON BOTH FRI AND
SATURDAY. THE H5 RIDGE UP TO 595 DEM JUST OFF THE COAST FRI INTO
EARLY SAT SHOULD PROVIDE ENOUGH SUBSIDENCE TO KEEP SHOWER ACTIVITY
LIMITED TO MAINLY INLAND AREAS. BY SATURDAY THE RIDGE GETS
SUPPRESSED FARTHER SOUTH AS MID TO UPPER TROUGH BEGINS TO DIG DOWN
THE EAST COAST WITH SFC TROUGH/FRONT SHIFTING SOUTHEAST AND CLOSER
TO THE COAST. BY LATE SUNDAY THROUGH TUESDAY...A MUCH DEEPER
COLUMN OF MOISTURE WILL BE PRESENT WITH PCP WATER VALUES UP ABOVE
2 INCHES. OVERALL EXPECT INCREASING CHC OF MORE WIDESPREAD
CONVECTION INTO EARLY NEXT WEEK WITH GREATER INSTABILITY AND
MOISTURE IN THE ATMOSPHERE AS DECENT UPPER LEVEL SUPPORT.
DEWPOINT TEMPS WILL BE BACK UP IN THE 70S WITH OVERNIGHT LOWS
IN THE MID 70S AND DAY TIME HIGHS REACHING INTO THE 90S. CLOUDS
AND PCP MAY KEEP VALUES SLIGHTLY LOWER EACH AFTERNOON INTO EARLY
NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...EXPECT VFR TO CONTINUE THROUGH THE VALID PERIOD. FEW/SCT
MID TO HIGH CLOUDS WILL CONTINUE TO LINGER ACROSS THE AREA WITH
LIGHT AND VARIABLE WINDS THROUGH THE MORNING HOURS. LATEST COMPUTER
MODELS ARE NOT SUPPORTING FOG DEVELOPMENT...BUT COULD NOT ENTIRELY
RULE OUT ISOLATED AREAS OF GROUND FOG...ESPECIALLY INLAND. AFTER
DAYBREAK...VFR WILL PREVAIL WITH COVERAGE IN MID TO HIGH CLOUDS
INCREASING. LIGHT SOUTH-SOUTHEAST WINDS IN THE MORNING WILL INCREASE
TO 10 KTS THROUGH THE AFTERNOON HOURS. ISOLATED SHOWERS AND TSTMS
COULD DEVELOP ACROSS THE CENTRAL CAROLINAS...POTENTIALLY MOVING AS
FAR EAST AS THE FLO/LBT AIRPORTS IN THE 20-23Z TIMEFRAME BUT
CONFIDENCE IS TOO LOW FOR INCLUSION IN THE FORECAST AT THIS TIME.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE WEDNESDAY THROUGH SATURDAY. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM/THROUGH TONIGHT/...
AS OF 630 AM TUESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
CANADIAN HIGH PRESSURE CENTERED OFF THE NEW JERSEY COAST IS
EXTENDING A SURFACE RIDGE AXIS SOUTHWESTWARD INTO EASTERN NORTH
CAROLINA AND CENTRAL SOUTH CAROLINA. ALTHOUGH THE MAIN AREA OF HIGH
PRESSURE WILL MOVE FARTHER OFFSHORE TONIGHT THE RIDGE AXIS WILL
REMAIN IN PLACE. THIS SHOULD KEEP OUR WINDS FROM VEERING AROUND TO
THE SOUTH AS NORMALLY OCCURS WITH A DEPARTING EAST COAST HIGH. EAST
TO SOUTHEAST WINDS 10-15 KNOTS THIS MORNING WILL DIMINISH TO AROUND
10 KNOTS FOR THIS AFTERNOON AND TONIGHT. ALTHOUGH THERE WILL BE AN
INCREASE IN CLOUD COVER THIS MORNING...IT APPEARS SHOWER CHANCES
WILL REMAIN CONFINED TO INTERIOR SECTIONS OF THE CAROLINAS. SEAS
CURRENTLY AVERAGE 2-3 FT AT THE BUOYS WITH SHORT WIND-DRIVEN
PERIODS. LITTLE CHANGE IS FORECAST INTO TONIGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...RETURN FLOW AROUND ATLANTIC RIDGE OF HIGH
PRESSURE WILL PERSIST THROUGH THE PERIOD. THE FLOW WILL VEER
AROUND FROM SOUTHEAST ON WED BECOMING MORE S-SW ON THURS. THE
WINDS WILL REMAIN AROUND 10 KTS SPIKING UP A BIT EACH AFTERNOON IN
THE SEA BREEZE. THE PERSISTENT ON SHORE PUSH WILL KEEP SEAS AROUND
2 TO 3 FT WITH SHORTER PERIOD WIND WAVES MIXING WITH A LONGER
PERIOD 9 SECOND SE SWELL.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT A SOUTH TO SOUTHWEST FLOW TO
CONTINUE THROUGH THE PERIOD AROUND ATLANTIC HIGH. THE WINDS WILL
VEER SLIGHTLY MORE INTO THE WEEKEND AS PIEDMONT TROUGH BECOMES
MORE PRONOUNCED AND COLD FRONT MOVES INTO THE CAROLINAS FROM THE
NORTHWEST OVER THE WEEKEND. THE GRADIENT WILL TIGHTEN BETWEEN INLAND
TROUGH/FRONT AND HIGH PRESSURE OFF SHORE TO PRODUCE WIND 10 TO 15 KTS
THROUGH THE PERIOD. THE INCREASED SOUTHERLY PUSH WILL PRODUCE A
RISE IN SEAS UP CLOSER TO 3 FT THROUGH THE WEEKEND.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...TRA/SGL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE THIS
MORNING...GIVING WAY TO A MOIST...SOUTHERLY LOW LEVEL RETURN FLOW
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM TUESDAY...
HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST THIS MORNING
EXTENDS SOUTHWEST OVER EASTERN NC/SC...WHILE A A RELATIVELY FAST
NORTHWESTERLY FLOW CONTINUES ALOFT. SOUTHEASTERLY RETURN FLOW
AROUND THE HIGH PRESSURE HAS BEEN CREATING SOME WEAK WARM ADVECTION
AND UPSLOPE FLOW...SUPPORTING THE DEVELOPMENT OF SCATTERED SHOWERS
OVER THE FOOTHILLS AND WESTERN PIEDMONT. HOWEVER... THE PRECIP HAS
STRUGGLED TO MOVE EAST ACROSS THE PIEDMONT ONCE IT MOVES OUT OF THE
BETTER LOW-LEVEL MOIST AXIS OVER WESTERN NC. RAP AND WATER VAPOR
IMAGERY SUGGEST A FEW WEAK DISTURBANCES ALOFT WILL DRIFT OVERHEAD
TODAY...WHICH MAY AID PRECIP IN MOVING FURTHER EAST ACROSS THE
PIEDMONT...BUT INSTABILITY WILL BE WEAK AND POPS WILL STILL BE
GRADUATED FROM CHANCE IN THE WEST TO SLIGHT CHANCE IN THE EAST.
SKIES WILL ALSO BE MORE CLOUDY OVER THE WESTERN CWA...WHERE FORECAST
SOUNDINGS SHOW A SOLID LAYER OF MOISTURE BETWEEN 850-700MB.
LOW-LEVEL THICKNESSES ARE ONLY SLIGHTLY HIGHER THAN THOSE OBSERVED
ON MONDAY OF AROUND 1400M. WITH PERIODS OF CLOUD COVER...HIGHS
SHOULD AGAIN BE IN THE LOW TO MID 80S.
TONIGHT...
SIMILAR TO THIS MORNING...SCATTERED SHOWER WILL BE POSSIBLE OVER THE
WESTERN CWA...WITH THE SHOWERS LIKELY TO WEAKEN AS THEY DRIFT EAST
INTO A MORE HOSTILE ENVIRONMENT AND SURFACE HIGH PRESSURE RIDGE.
LOWS IN THE UPPER 60S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 245 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT...
HIGH PRESSURE RIDGING ALONG THE CAROLINA COAST WILL WEAKEN WEDNESDAY
AS THE PARENT HIGH MOVES FURTHER OFF THE MID-ATLANTIC COAST AND COLD
FRONT MOVES THROUGH THE MIDWEST STATES. INSTABILITY...WHILE
SLIGHTLY GREATER THAN FORECAST FOR TODAY... WILL CONTINUE TO BE WEAK
OVER CENTRAL NC DESPITE RISING PRECIP WATER. WEAK WARM ADVECTION
AND UPSLOPE SHOULD STILL FAVOR SCATTERED SHOWERS AND ISOLATED STORMS
OVER THE WESTERN PIEDMONT. WHILE HIGHS WILL STILL BE BELOW
NORMAL...FORECAST SOUNDINGS SHOW A LITTLE LESS CLOUD COVER AND
BETTER MIXING...WHICH SHOULD SUPPORT HIGHS A COUPLE DEGREES WARMER
THAN TODAY...85-88. LOWS AROUND 70. -SMITH
FOR THURSDAY/THURSDAY NIGHT: THE CANADIAN VORTEX DRIFTS SLOWLY
EASTWARD TO CENTRAL ONTARIO THU/THU NIGHT AS WEAK MID LEVEL RIDGING
PASSES OVER NC... INSTIGATING SUBTLE WARMING ALOFT (500-300 MB) WITH
A VERY LIGHT WESTERLY MID LEVEL FLOW AND THE JET STREAM DISPLACED
WELL TO OUR NORTH ACROSS THE NRN GREAT LAKES... LARGE SCALE FORCED
ASCENT WILL BE LIMITED TO LOWER LEVEL MASS CONVERGENCE OVER THE NC
MOUNTAINS/FOOTHILLS INTO VA... IN THE LOW LEVEL MOIST CONVEYOR ZONE
WHERE PW VALUES WILL BE GREATEST (NEAR 2.0 INCHES). SREF
PROBABILITIES OF MEASURABLE RAIN REACH 50-70% OVER THE NW HALF OF
THE FORECAST AREA LATE THU MORNING THROUGH THE AFTERNOON...
CORRESPONDING TO MODEL-INDICATED AREAS OF ENHANCED LOW LEVEL
MOISTURE TRANSPORT ON THE PERIPHERY OF THE OFFSHORE SURFACE HIGH...
WITH PROBABILITIES OF 10% OR LOWER IN THE EAST WHERE FORECAST
SOUNDINGS SHOW SEVERAL LAYERS OF DRY AIR THROUGH THE COLUMN WITH
MINIMAL INSTABILITY. WILL KEEP CHANCE POPS ACROSS THE WRN AND FAR
NRN CWA... ON THE PERIPHERY OF THE RIDGE CORE... WITH ISOLATED POPS
OVER MUCH OF THE EAST. THE NAM HINTS AT POTENTIAL SEA-BREEZE
CONVECTION WORKING INTO THE EXTREME SE FORECAST AREA... SO WILL PUT
A SECONDARY POP MAX (BUT STILL JUST SMALL COVERAGE) HERE. HIGHS
86-90. MODELS AGREE ON ANY PRECIP SHUTTING OFF NEAR SUNSET... AND
EXPECT LARGELY DRY WEATHER OVERNIGHT BUT WITH MID CLOUDS MOVING IN
(BLOWOFF CLOUDS FROM MORE ORGANIZED/WIDESPREAD CONVECTION OVER
WV/KY/TN)... AND WE SHOULD SEE STRATUS/FOG FORMATION OVERNIGHT GIVEN
THE LIGHT SOUTH/SW FLOW AND RISING LOW LEVEL MOISTURE. LOWS 69-73.
FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN VORTEX IS EXPECTED TO CONTINUE
ITS EASTWARD WOBBLE ACROSS ONTARIO TO THE TIP OF JAMES BAY DURING
THIS TIME FRAME. THE GFS HAS BEEN TRENDING SLOWER WITH THIS IN
RECENT RUNS... AND AS A RESULT IT NOW DELAYS THE ARRIVAL OF THE
GREATER COVERAGE OF CONVECTION WITHIN THE STREAM OF PREFRONTAL WARM
AIR ADVECTION... AND KEEPS THE FAR ERN CWA MAINLY DRY THROUGH FRI
NIGHT. THE GFS KEEPS THE UPPER LEVEL ANTICYCLONE CENTER OVER THE
CAROLINAS... AND WITH THE SWRLY UPPER JET CORE CROSSING THE GREAT
LAKES... THE BULK OF THE UPPER DIVERGENCE SKIRTS BY TO OUR NW AND
NORTH. THE SLIGHTLY FASTER ECMWF IS A BIT MORE EMPHATIC WITH
CONVECTION ACROSS CENTRAL NC ALONG THE LEE SURFACE TROUGH AS THE MID
LEVEL TROUGH AXIS APPROACHES... A SOLUTION THAT CANNOT BE DISCOUNTED
GIVEN THE EXPECTED MODERATE INSTABILITY (MLCAPE NEAR 1500 J/KG)...
SO WILL BRING IN CHANCE POPS AREAWIDE FRIDAY (MAINLY AFTERNOON INTO
EARLY EVENING)... DECREASING AFTER MID EVENING AS SUBSTANTIAL
FORCING FOR ASCENT CONTINUES TO BE LACKING... WHILE 850 MB FLOW
BECOMES MORE WESTERLY. FORECAST SOUNDINGS SUGGEST THAT THERE WILL BE
ENOUGH THIN SPOTS IN THE MID CLOUD COVERAGE TO FOSTER RADIATIONAL
COOLING AND ANOTHER ROUND OF STRATUS/FOG OVERNIGHT. HIGHS 87-91 WITH
THICKNESSES CLOSE TO NORMAL. LOWS 69-74. -GIH
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 305 AM TUESDAY...
STILL APPEARS LIKELY THAT WE`LL SEE THE BEST CHANCE OF
SHOWERS/STORMS DURING THIS FORECAST CYCLE ON SATURDAY... WITH LOWER
CHANCES LARGELY CONFINED TO SRN SECTIONS ON SUNDAY/MONDAY. THE
VORTEX WILL CROSS QUEBEC TO THE MARITIMES WHILE ADDITIONAL ENERGY TO
ITS NORTH DROPS INTO ITS WEST SIDE... ALLOWING THE LONGWAVE TROUGH
TO DEEPEN DOWN THROUGH THE GREAT LAKES/NORTHEAST/MIDATLANTIC...
EVENTUALLY LEADING TO STRENGTHENING WNW MID LEVEL FLOW OVER NC.
EXPECT A GOOD CHANCE OF SHOWERS/STORMS AREAWIDE SATURDAY AS THE
SURFACE FRONT APPROACHES... WITH A SOUTHWARD SUPPRESSION OF THESE
RAIN CHANCES SUNDAY/MONDAY AS THE FRONT DROPS SLOWLY THROUGH THE
AREA... PROPELLED BY THE STRENGTHENING WNW STEERING FLOW. GFS/ECMWF
THICKNESSES SUPPORT HIGHS NEAR TO JUST BELOW NORMAL... WITH LOWS A
BIT ABOVE NORMAL SAT NIGHT TRENDING TO JUST BELOW NORMAL SUNDAY
NIGHT. -GIH
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 145 AM TUESDAY...
SHOWERS CONTINUE TO DEVELOP WEST OVER THE WESTERN PIEDMONT AND
FOOTHILLS WHERE WEAK WARM ADVECTION AND UPSLOPE FLOW IS MORE
PROMINENT...BUT THE TREND HAS BEEN FOR THE SHOWERS TO DISSIPATE AS
THEY DRIFT EAST NEAR KINT/KGSO. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS FORECAST TO REMAIN RELATIVELY STATIONARY TODAY...WITH
LITTLE CHANGE IN THE FLOW OVER CENTRAL NC. THUS...MOISTURE WILL
CONTINUE TO BE BEST OVER WESTERN NC AND SHOWERS OR STORMS WILL
STRUGGLE TO MOVE ACROSS THE PIEDMONT. FORECAST SOUNDINGS SHOW
CEILINGS IN THE 3000-5000 FT RANGE TODAY...ALTHOUGH MVFR CEILINGS
CERTAINLY WILL BE POSSIBLE AT KGSO AND KINT.
OUTLOOK...
EARLY MORNING STRATUS WILL BE A PROBLEM EACH MORNING THIS
WEEK AS A MOIST SOUTHERLY FLOW PERSISTS. THE CHANCE OF SHOWERS AND
STORMS WILL EXIST EACH DAY...PARTICULARLY OVER WESTERN NC. THE
WEATHER WILL BECOME MORE UNSETTLED BY THE END OF THE WEEK AS A COLD
FRONT MOVES INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE THIS
MORNING...GIVING WAY TO A MOIST...SOUTHERLY LOW LEVEL RETURN FLOW
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 AM TUESDAY...
HIGH PRESSURE CENTERED OFF THE MID-ATLANTIC COAST THIS MORNING
EXTENDS SOUTHWEST OVER EASTERN NC/SC...WHILE A A RELATIVELY FAST
NORTHWESTERLY FLOW CONTINUES ALOFT. SOUTHEASTERLY RETURN FLOW
AROUND THE HIGH PRESSURE HAS BEEN CREATING SOME WEAK WARM ADVECTION
AND UPSLOPE FLOW...SUPPORTING THE DEVELOPMENT OF SCATTERED SHOWERS
OVER THE FOOTHILLS AND WESTERN PIEDMONT. HOWEVER... THE PRECIP HAS
STRUGGLED TO MOVE EAST ACROSS THE PIEDMONT ONCE IT MOVES OUT OF THE
BETTER LOW-LEVEL MOIST AXIS OVER WESTERN NC. RAP AND WATER VAPOR
IMAGERY SUGGEST A FEW WEAK DISTURBANCES ALOFT WILL DRIFT OVERHEAD
TODAY...WHICH MAY AID PRECIP IN MOVING FURTHER EAST ACROSS THE
PIEDMONT...BUT INSTABILITY WILL BE WEAK AND POPS WILL STILL BE
GRADUATED FROM CHANCE IN THE WEST TO SLIGHT CHANCE IN THE EAST.
SKIES WILL ALSO BE MORE CLOUDY OVER THE WESTERN CWA...WHERE FORECAST
SOUNDINGS SHOW A SOLID LAYER OF MOISTURE BETWEEN 850-700MB.
LOW-LEVEL THICKNESSES ARE ONLY SLIGHTLY HIGHER THAN THOSE OBSERVED
ON MONDAY OF AROUND 1400M. WITH PERIODS OF CLOUD COVER...HIGHS
SHOULD AGAIN BE IN THE LOW TO MID 80S.
TONIGHT...
SIMILAR TO THIS MORNING...SCATTERED SHOWER WILL BE POSSIBLE OVER THE
WESTERN CWA...WITH THE SHOWERS LIKELY TO WEAKEN AS THEY DRIFT EAST
INTO A MORE HOSTILE ENVIRONMENT AND SURFACE HIGH PRESSURE RIDGE.
LOWS IN THE UPPER 60S.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 245 AM TUESDAY...
WEDNESDAY AND WEDNESDAY NIGHT...
HIGH PRESSURE RIDGING ALONG THE CAROLINA COAST WILL WEAKEN WEDNESDAY
AS THE PARENT HIGH MOVES FURTHER OFF THE MID-ATLANTIC COAST AND COLD
FRONT MOVES THROUGH THE MIDWEST STATES. INSTABILITY...WHILE
SLIGHTLY GREATER THAN FORECAST FOR TODAY... WILL CONTINUE TO BE WEAK
OVER CENTRAL NC DESPITE RISING PRECIP WATER. WEAK WARM ADVECTION
AND UPSLOPE SHOULD STILL FAVOR SCATTERED SHOWERS AND ISOLATED STORMS
OVER THE WESTERN PIEDMONT. WHILE HIGHS WILL STILL BE BELOW
NORMAL...FORECAST SOUNDINGS SHOW A LITTLE LESS CLOUD COVER AND
BETTER MIXING...WHICH SHOULD SUPPORT HIGHS A COUPLE DEGREES WARMER
THAN TODAY...85-88. LOWS AROUND 70. -SMITH
FOR THURSDAY/THURSDAY NIGHT: THE CANADIAN VORTEX DRIFTS SLOWLY
EASTWARD TO CENTRAL ONTARIO THU/THU NIGHT AS WEAK MID LEVEL RIDGING
PASSES OVER NC... INSTIGATING SUBTLE WARMING ALOFT (500-300 MB) WITH
A VERY LIGHT WESTERLY MID LEVEL FLOW AND THE JET STREAM DISPLACED
WELL TO OUR NORTH ACROSS THE NRN GREAT LAKES... LARGE SCALE FORCED
ASCENT WILL BE LIMITED TO LOWER LEVEL MASS CONVERGENCE OVER THE NC
MOUNTAINS/FOOTHILLS INTO VA... IN THE LOW LEVEL MOIST CONVEYOR ZONE
WHERE PW VALUES WILL BE GREATEST (NEAR 2.0 INCHES). SREF
PROBABILITIES OF MEASURABLE RAIN REACH 50-70% OVER THE NW HALF OF
THE FORECAST AREA LATE THU MORNING THROUGH THE AFTERNOON...
CORRESPONDING TO MODEL-INDICATED AREAS OF ENHANCED LOW LEVEL
MOISTURE TRANSPORT ON THE PERIPHERY OF THE OFFSHORE SURFACE HIGH...
WITH PROBABILITIES OF 10% OR LOWER IN THE EAST WHERE FORECAST
SOUNDINGS SHOW SEVERAL LAYERS OF DRY AIR THROUGH THE COLUMN WITH
MINIMAL INSTABILITY. WILL KEEP CHANCE POPS ACROSS THE WRN AND FAR
NRN CWA... ON THE PERIPHERY OF THE RIDGE CORE... WITH ISOLATED POPS
OVER MUCH OF THE EAST. THE NAM HINTS AT POTENTIAL SEA-BREEZE
CONVECTION WORKING INTO THE EXTREME SE FORECAST AREA... SO WILL PUT
A SECONDARY POP MAX (BUT STILL JUST SMALL COVERAGE) HERE. HIGHS
86-90. MODELS AGREE ON ANY PRECIP SHUTTING OFF NEAR SUNSET... AND
EXPECT LARGELY DRY WEATHER OVERNIGHT BUT WITH MID CLOUDS MOVING IN
(BLOWOFF CLOUDS FROM MORE ORGANIZED/WIDESPREAD CONVECTION OVER
WV/KY/TN)... AND WE SHOULD SEE STRATUS/FOG FORMATION OVERNIGHT GIVEN
THE LIGHT SOUTH/SW FLOW AND RISING LOW LEVEL MOISTURE. LOWS 69-73.
FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN VORTEX IS EXPECTED TO CONTINUE
ITS EASTWARD WOBBLE ACROSS ONTARIO TO THE TIP OF JAMES BAY DURING
THIS TIME FRAME. THE GFS HAS BEEN TRENDING SLOWER WITH THIS IN
RECENT RUNS... AND AS A RESULT IT NOW DELAYS THE ARRIVAL OF THE
GREATER COVERAGE OF CONVECTION WITHIN THE STREAM OF PREFRONTAL WARM
AIR ADVECTION... AND KEEPS THE FAR ERN CWA MAINLY DRY THROUGH FRI
NIGHT. THE GFS KEEPS THE UPPER LEVEL ANTICYCLONE CENTER OVER THE
CAROLINAS... AND WITH THE SWRLY UPPER JET CORE CROSSING THE GREAT
LAKES... THE BULK OF THE UPPER DIVERGENCE SKIRTS BY TO OUR NW AND
NORTH. THE SLIGHTLY FASTER ECMWF IS A BIT MORE EMPHATIC WITH
CONVECTION ACROSS CENTRAL NC ALONG THE LEE SURFACE TROUGH AS THE MID
LEVEL TROUGH AXIS APPROACHES... A SOLUTION THAT CANNOT BE DISCOUNTED
GIVEN THE EXPECTED MODERATE INSTABILITY (MLCAPE NEAR 1500 J/KG)...
SO WILL BRING IN CHANCE POPS AREAWIDE FRIDAY (MAINLY AFTERNOON INTO
EARLY EVENING)... DECREASING AFTER MID EVENING AS SUBSTANTIAL
FORCING FOR ASCENT CONTINUES TO BE LACKING... WHILE 850 MB FLOW
BECOMES MORE WESTERLY. FORECAST SOUNDINGS SUGGEST THAT THERE WILL BE
ENOUGH THIN SPOTS IN THE MID CLOUD COVERAGE TO FOSTER RADIATIONAL
COOLING AND ANOTHER ROUND OF STRATUS/FOG OVERNIGHT. HIGHS 87-91 WITH
THICKNESSES CLOSE TO NORMAL. LOWS 69-74. -GIH
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 318 PM MONDAY...
SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN
WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE
CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK
PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND
INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH
DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM
PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE HIGH CHANCE
POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT.
SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE
PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL
NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST
A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO
MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR
POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON
MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR
DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE
NORTHERN LAKES TO TRANSLATE INTO OUR REGION.
TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER
AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE
A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5
DEGREES ABOVE NORMAL.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 145 AM TUESDAY...
SHOWERS CONTINUE TO DEVELOP WEST OVER THE WESTERN PIEDMONT AND
FOOTHILLS WHERE WEAK WARM ADVECTION AND UPSLOPE FLOW IS MORE
PROMINENT...BUT THE TREND HAS BEEN FOR THE SHOWERS TO DISSIPATE AS
THEY DRIFT EAST NEAR KINT/KGSO. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS FORECAST TO REMAIN RELATIVELY STATIONARY TODAY...WITH
LITTLE CHANGE IN THE FLOW OVER CENTRAL NC. THUS...MOISTURE WILL
CONTINUE TO BE BEST OVER WESTERN NC AND SHOWERS OR STORMS WILL
STRUGGLE TO MOVE ACROSS THE PIEDMONT. FORECAST SOUNDINGS SHOW
CEILINGS IN THE 3000-5000 FT RANGE TODAY...ALTHOUGH MVFR CEILINGS
CERTAINLY WILL BE POSSIBLE AT KGSO AND KINT.
OUTLOOK...
EARLY MORNING STRATUS WILL BE A PROBLEM EACH MORNING THIS
WEEK AS A MOIST SOUTHERLY FLOW PERSISTS. THE CHANCE OF SHOWERS AND
STORMS WILL EXIST EACH DAY...PARTICULARLY OVER WESTERN NC. THE
WEATHER WILL BECOME MORE UNSETTLED BY THE END OF THE WEEK AS A COLD
FRONT MOVES INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
222 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE
TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL
THROUGH MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 915 PM MONDAY...
TONIGHT:
SURFACE HIGH PRESSURE HAS SHIFTED JUST OFF THE SOUTHERN MID-ATLANTIC
COAST THIS EVENING... WHILE THE MID/UPPER LEVEL FLOW ALOFT CONTINUES
TO BE OUT OF THE NORTHWEST. THIS HAS RESULTED IN A LIGHT
SOUTH/SOUTHEASTERLY SURFACE/LOW LEVEL RETURN FLOW UP AND INTO THE
HIGHER TERRAIN ALONG WITH WEAK PERTURBATION MOVING THROUGH THE
NORTHWEST FLOW ALOFT... WHICH HAS ALLOWED SOME SHOWERS TO DEVELOP IN
THE HIGHER TERRAIN. THESE SHOWERS (AND PERHAPS A THUNDERSTORM OR
TWO) HAVE HAD A HARD TIME COMING OFF THE HIGHER TERRAIN AND INTO THE
PIEDMONT. HOWEVER... THE LATEST HRRR AND SOME OF THE OTHER HI-RES
GUIDANCE IS NOW SHOWING THIS ACTIVITY SLOWLY SHIFTING EASTWARD AND
INTO THE PIEDMONT LATER THIS EVENING INTO THE OVERNIGHT HOURS. GIVEN
THE RATHER WEAK INSTABILITY EXPECTED OVER OUR AREA... WE DO NOT
ANTICIPATE ANY SVR WEATHER FROM THIS ACTIVITY. HOWEVER... WE COULD
SEE A BRIEF HEAVY DOWNPOUR AND REDUCED VISIBILITY AS A SHOWER AND/OR
STORM MOVES ACROSS A GIVEN LOCATION. THE HIGHEST PROBABILITIES WILL
REMAIN ACROSS THE NORTH/NORTHWESTERN PIEDMONT THIS EVENING/TONIGHT.
THUS... WILL CONTINUE TO SHOW THE FAR NORTHWEST PIEDMONT WITH THE
HIGHEST POPS AFTER MIDNIGHT (CHANCE... 25-40 PERCENT) TO SLIGHT
CHANCE JUST WEST OF RALEIGH. GIVEN THIS EXPECT SKIES WILL GENERALLY
BE PARTLY TO MOSTLY CLOUDY/CLOUDY OVERNIGHT... WHICH WILL HELP TO
KEEP TEMPS UP A BIT TONIGHT... ALONG WITH THE INCREASE IN LOW LEVEL
MOISTURE. THUS... EXPECT LOWS TO RANGE FROM THE MID 60S EAST TO
UPPER 60S WEST. -BSD
TUESDAY:
EXPECT AN INCREASING POTENTIAL FOR SHOWER (THUNDERSTORM) ACTIVITY
TUESDAY MORNING (AFTERNOON) AS A SEASONABLY MOIST SOUTHERLY
LOW-LEVEL RETURN FLOW AIDS IN MARGINAL TO MODERATE DIURNAL
DESTABILIZATION IN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE AND AN
INCREASED POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN NW FLOW
ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20-50%...HIGHEST IN
THE WESTERN PIEDMONT AND LOWEST IN THE COASTAL PLAIN WHERE LOW-LEVEL
MOISTURE /DIURNAL DESTABILIZATION/ IS EXPECTED TO BE MARGINAL. HIGHS
WILL BE SIMILAR TO TODAY AND PRIMARILY DEPEND ON CLOUD COVER...
RANGING FROM NEAR 80F IN THE N/NW PIEDMONT TO MID/UPPER 80S IN THE
SANDHILLS AND COASTAL PLAIN. -VINCENT
&&
.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 318 PM MONDAY / 220 AM TUESDAY...
TUESDAY NIGHT...APPROACH OF A WEAK MID-UPPER LEVEL DISTURBANCE
COUPLED WITH AN INCREASINGLY MOIST AIR MASS WILL SUPPORT THE
POTENTIAL FOR A FEW SHOWERS/ISOLATED THUNDER WELL INTO THE
NIGHT...MAINLY OVER THE NW PIEDMONT. INCREASING/THICKENING CLOUD
COVER AND A LIGHT SLY WIND WILL RESULT IN A FAIRLY UNIFORM TEMP
FIELD OVERNIGHT. MIN TEMPS UPPER 60S TO AROUND 70.
WEDNESDAY AND WEDNESDAY NIGHT...THE MID-UPPER LEVEL TROUGH TRANSLATE
SLOWLY EWD TOWARD AND ACROSS THE MID ATLANTIC AND CAROLINAS WED
AFTERNOON-EVENING. 12Z GFS NOT TOO IMPRESSIVE WITH ITS CONVECTIVE
PARAMETERS WED AFTERNOON-EVENING ...DEPICTING MARGINAL/SLIGHT
INSTABILITY AT BEST. STILL...FAVORED LOW LEVEL CONFLUENCE OVER THE
WESTERN PIEDMONT DURING PRIME HEATING SUPPORT HIGH CHANCE POP IN
THIS REGION....WITH POPS TAPERING TO SLIGHT CHANCE OVER THE SOUTHERN
COASTAL PLAINS AND SANDHILLS. MORE CLOUDS THAN SUN WILL LIMIT NORMAL
DIURNAL TEMP RISE IN THE WEST-NW WHERE MAX TEMPS EXPECTED TO BE
LOWER 80S. PARTIAL SUN OVER THE SE HALF SHOULD WARM TEMPS WELL INTO
THE 80S. CONSIDERABLE CLOUDINESS WEDNESDAY NIGHT WILL MAINTAIN HUMID
CONDITIONS. MIN TEMPS AROUND 70/LOWER 70S. -WSS
FOR THURSDAY/THURSDAY NIGHT: THE CANADIAN VORTEX DRIFTS SLOWLY
EASTWARD TO CENTRAL ONTARIO THU/THU NIGHT AS WEAK MID LEVEL RIDGING
PASSES OVER NC... INSTIGATING SUBTLE WARMING ALOFT (500-300 MB) WITH
A VERY LIGHT WESTERLY MID LEVEL FLOW AND THE JET STREAM DISPLACED
WELL TO OUR NORTH ACROSS THE NRN GREAT LAKES... LARGE SCALE FORCED
ASCENT WILL BE LIMITED TO LOWER LEVEL MASS CONVERGENCE OVER THE NC
MOUNTAINS/FOOTHILLS INTO VA... IN THE LOW LEVEL MOIST CONVEYOR ZONE
WHERE PW VALUES WILL BE GREATEST (NEAR 2.0 INCHES). SREF
PROBABILITIES OF MEASURABLE RAIN REACH 50-70% OVER THE NW HALF OF
THE FORECAST AREA LATE THU MORNING THROUGH THE AFTERNOON...
CORRESPONDING TO MODEL-INDICATED AREAS OF ENHANCED LOW LEVEL
MOISTURE TRANSPORT ON THE PERIPHERY OF THE OFFSHORE SURFACE HIGH...
WITH PROBABILITIES OF 10% OR LOWER IN THE EAST WHERE FORECAST
SOUNDINGS SHOW SEVERAL LAYERS OF DRY AIR THROUGH THE COLUMN WITH
MINIMAL INSTABILITY. WILL KEEP CHANCE POPS ACROSS THE WRN AND FAR
NRN CWA... ON THE PERIPHERY OF THE RIDGE CORE... WITH ISOLATED POPS
OVER MUCH OF THE EAST. THE NAM HINTS AT POTENTIAL SEA-BREEZE
CONVECTION WORKING INTO THE EXTREME SE FORECAST AREA... SO WILL PUT
A SECONDARY POP MAX (BUT STILL JUST SMALL COVERAGE) HERE. HIGHS
86-90. MODELS AGREE ON ANY PRECIP SHUTTING OFF NEAR SUNSET... AND
EXPECT LARGELY DRY WEATHER OVERNIGHT BUT WITH MID CLOUDS MOVING IN
(BLOWOFF CLOUDS FROM MORE ORGANIZED/WIDESPREAD CONVECTION OVER
WV/KY/TN)... AND WE SHOULD SEE STRATUS/FOG FORMATION OVERNIGHT GIVEN
THE LIGHT SOUTH/SW FLOW AND RISING LOW LEVEL MOISTURE. LOWS 69-73.
FOR FRIDAY/FRIDAY NIGHT: THE CANADIAN VORTEX IS EXPECTED TO CONTINUE
ITS EASTWARD WOBBLE ACROSS ONTARIO TO THE TIP OF JAMES BAY DURING
THIS TIME FRAME. THE GFS HAS BEEN TRENDING SLOWER WITH THIS IN
RECENT RUNS... AND AS A RESULT IT NOW DELAYS THE ARRIVAL OF THE
GREATER COVERAGE OF CONVECTION WITHIN THE STREAM OF PREFRONTAL WARM
AIR ADVECTION... AND KEEPS THE FAR ERN CWA MAINLY DRY THROUGH FRI
NIGHT. THE GFS KEEPS THE UPPER LEVEL ANTICYCLONE CENTER OVER THE
CAROLINAS... AND WITH THE SWRLY UPPER JET CORE CROSSING THE GREAT
LAKES... THE BULK OF THE UPPER DIVERGENCE SKIRTS BY TO OUR NW AND
NORTH. THE SLIGHTLY FASTER ECMWF IS A BIT MORE EMPHATIC WITH
CONVECTION ACROSS CENTRAL NC ALONG THE LEE SURFACE TROUGH AS THE MID
LEVEL TROUGH AXIS APPROACHES... A SOLUTION THAT CANNOT BE DISCOUNTED
GIVEN THE EXPECTED MODERATE INSTABILITY (MLCAPE NEAR 1500 J/KG)...
SO WILL BRING IN CHANCE POPS AREAWIDE FRIDAY (MAINLY AFTERNOON INTO
EARLY EVENING)... DECREASING AFTER MID EVENING AS SUBSTANTIAL
FORCING FOR ASCENT CONTINUES TO BE LACKING... WHILE 850 MB FLOW
BECOMES MORE WESTERLY. FORECAST SOUNDINGS SUGGEST THAT THERE WILL BE
ENOUGH THIN SPOTS IN THE MID CLOUD COVERAGE TO FOSTER RADIATIONAL
COOLING AND ANOTHER ROUND OF STRATUS/FOG OVERNIGHT. HIGHS 87-91 WITH
THICKNESSES CLOSE TO NORMAL. LOWS 69-74. -GIH
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 318 PM MONDAY...
SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN
WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE
CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK
PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND
INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH
DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM
PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE HIGH CHANCE
POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT.
SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE
PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL
NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST
A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO
MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR
POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON
MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR
DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE
NORTHERN LAKES TO TRANSLATE INTO OUR REGION.
TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER
AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE
A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5
DEGREES ABOVE NORMAL.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 145 AM TUESDAY...
SHOWERS CONTINUE TO DEVELOP WEST OVER THE WESTERN PIEDMONT AND
FOOTHILLS WHERE WEAK WARM ADVECTION AND UPSLOPE FLOW IS MORE
PROMINENT...BUT THE TREND HAS BEEN FOR THE SHOWERS TO DISSIPATE AS
THEY DRIFT EAST NEAR KINT/KGSO. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS FORECAST TO REMAIN RELATIVELY STATIONARY TODAY...WITH
LITTLE CHANGE IN THE FLOW OVER CENTRAL NC. THUS...MOISTURE WILL
CONTINUE TO BE BEST OVER WESTERN NC AND SHOWERS OR STORMS WILL
STRUGGLE TO MOVE ACROSS THE PIEDMONT. FORECAST SOUNDINGS SHOW
CEILINGS IN THE 3000-5000 FT RANGE TODAY...ALTHOUGH MVFR CEILINGS
CERTAINLY WILL BE POSSIBLE AT KGSO AND KINT.
OUTLOOK...
EARLY MORNING STRATUS WILL BE A PROBLEM EACH MORNING THIS
WEEK AS A MOIST SOUTHERLY FLOW PERSISTS. THE CHANCE OF SHOWERS AND
STORMS WILL EXIST EACH DAY...PARTICULARLY OVER WESTERN NC. THE
WEATHER WILL BECOME MORE UNSETTLED BY THE END OF THE WEEK AS A COLD
FRONT MOVES INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD
NEAR TERM...BSD/VINCENT
SHORT TERM..WSS/HARTFIELD
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
145 AM EDT TUE AUG 6 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO SLOWLY SHIFT FURTHER OFFSHORE
TONIGHT. A MOIST SOUTHERLY LOW LEVEL RETURN FLOW WILL PREVAIL
THROUGH MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 915 PM MONDAY...
TONIGHT:
SURFACE HIGH PRESSURE HAS SHIFTED JUST OFF THE SOUTHERN MID-ATLANTIC
COAST THIS EVENING... WHILE THE MID/UPPER LEVEL FLOW ALOFT CONTINUES
TO BE OUT OF THE NORTHWEST. THIS HAS RESULTED IN A LIGHT
SOUTH/SOUTHEASTERLY SURFACE/LOW LEVEL RETURN FLOW UP AND INTO THE
HIGHER TERRAIN ALONG WITH WEAK PERTURBATION MOVING THROUGH THE
NORTHWEST FLOW ALOFT... WHICH HAS ALLOWED SOME SHOWERS TO DEVELOP IN
THE HIGHER TERRAIN. THESE SHOWERS (AND PERHAPS A THUNDERSTORM OR
TWO) HAVE HAD A HARD TIME COMING OFF THE HIGHER TERRAIN AND INTO THE
PIEDMONT. HOWEVER... THE LATEST HRRR AND SOME OF THE OTHER HI-RES
GUIDANCE IS NOW SHOWING THIS ACTIVITY SLOWLY SHIFTING EASTWARD AND
INTO THE PIEDMONT LATER THIS EVENING INTO THE OVERNIGHT HOURS. GIVEN
THE RATHER WEAK INSTABILITY EXPECTED OVER OUR AREA... WE DO NOT
ANTICIPATE ANY SVR WEATHER FROM THIS ACTIVITY. HOWEVER... WE COULD
SEE A BRIEF HEAVY DOWNPOUR AND REDUCED VISIBILITY AS A SHOWER AND/OR
STORM MOVES ACROSS A GIVEN LOCATION. THE HIGHEST PROBABILITIES WILL
REMAIN ACROSS THE NORTH/NORTHWESTERN PIEDMONT THIS EVENING/TONIGHT.
THUS... WILL CONTINUE TO SHOW THE FAR NORTHWEST PIEDMONT WITH THE
HIGHEST POPS AFTER MIDNIGHT (CHANCE... 25-40 PERCENT) TO SLIGHT
CHANCE JUST WEST OF RALEIGH. GIVEN THIS EXPECT SKIES WILL GENERALLY
BE PARTLY TO MOSTLY CLOUDY/CLOUDY OVERNIGHT... WHICH WILL HELP TO
KEEP TEMPS UP A BIT TONIGHT... ALONG WITH THE INCREASE IN LOW LEVEL
MOISTURE. THUS... EXPECT LOWS TO RANGE FROM THE MID 60S EAST TO
UPPER 60S WEST. -BSD
TUESDAY:
EXPECT AN INCREASING POTENTIAL FOR SHOWER (THUNDERSTORM) ACTIVITY
TUESDAY MORNING (AFTERNOON) AS A SEASONABLY MOIST SOUTHERLY
LOW-LEVEL RETURN FLOW AIDS IN MARGINAL TO MODERATE DIURNAL
DESTABILIZATION IN THE PRESENCE OF WEAK LOW-LEVEL CONVERGENCE AND AN
INCREASED POTENTIAL FOR SMALL AMPLITUDE DISTURBANCES IN NW FLOW
ALOFT. WILL INDICATE PRECIP CHANCES RANGING FROM 20-50%...HIGHEST IN
THE WESTERN PIEDMONT AND LOWEST IN THE COASTAL PLAIN WHERE LOW-LEVEL
MOISTURE /DIURNAL DESTABILIZATION/ IS EXPECTED TO BE MARGINAL. HIGHS
WILL BE SIMILAR TO TODAY AND PRIMARILY DEPEND ON CLOUD COVER...
RANGING FROM NEAR 80F IN THE N/NW PIEDMONT TO MID/UPPER 80S IN THE
SANDHILLS AND COASTAL PLAIN. -VINCENT
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 318 PM MONDAY...
TUESDAY NIGHT...APPROACH OF A WEAK MID-UPPER LEVEL DISTURBANCE
COUPLED WITH AN INCREASINGLY MOIST AIR MASS WILL SUPPORT THE
POTENTIAL FOR A FEW SHOWERS/ISOLATED THUNDER WELL INTO THE
NIGHT...MAINLY OVER THE NW PIEDMONT. INCREASING/THICKENING CLOUD
COVER AND A LIGHT SLY WIND WILL RESULT IN A FAIRLY UNIFORM TEMP
FIELD OVERNIGHT. MIN TEMPS UPPER 60S TO AROUND 70.
WEDNESDAY AND WEDNESDAY NIGHT...THE MID-UPPER LEVEL TROUGH TRANSLATE
SLOWLY EWD TOWARD AND ACROSS THE MID ATLANTIC AND CAROLINAS WED
AFTERNOON-EVENING. 12Z GFS NOT TOO IMPRESSIVE WITH ITS CONVECTIVE
PARAMETERS WED AFTERNOON-EVENING ...DEPICTING MARGINAL/SLIGHT
INSTABILITY AT BEST. STILL...FAVORED LOW LEVEL CONFLUENCE OVER THE
WESTERN PIEDMONT DURING PRIME HEATING SUPPORT HIGH CHANCE POP IN
THIS REGION....WITH POPS TAPERING TO SLIGHT CHANCE OVER THE SOUTHERN
COASTAL PLAINS AND SANDHILLS. MORE CLOUDS THAN SUN WILL LIMIT NORMAL
DIURNAL TEMP RISE IN THE WEST-NW WHERE MAX TEMPS EXPECTED TO BE
LOWER 80S. PARTIAL SUN OVER THE SE HALF SHOULD WARM TEMPS WELL INTO
THE 80S. CONSIDERABLE CLOUDINESS WEDNESDAY NIGHT WILL MAINTAIN HUMID
CONDITIONS. MIN TEMPS AROUND 70/LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 318 PM MONDAY...
THURSDAY...
LINGERING MID-UPPER LEVEL TROUGH WILL MAINTAIN A DECENT THREAT FOR
SCATTERED SHOWERS AND THUNDERSTORMS THURSDAY AS LOW LEVEL
CONVERGENCE PROJECTED TO BE MAXIMIZED OVER OUR REGION. ONLY CAVEAT
IS THAT BUILDING MID-UPPER LEVEL HEIGHTS MAY RESULT IN THE
DEVELOPMENT OF A LAYER OF WARM AIR ALOFT...POSSIBLY CAPPING AIR MASS
AND LIMITING CONVECTIVE DEVELOPMENT. HOWEVER CONSIDERING THE AMOUNT
OF LOW LEVEL CONVERGENCE AND AVAILABLE MOISTURE SUPPORT CHANCE POPS
THURSDAY.
FRIDAY-SATURDAY....SUB TROPICAL RIDGE PROJECTED TO EXPAND/STRENGTHEN
WEST-TO-EAST ACROSS THE LOWER MS VALLEY AND SE U.S. THIS WILL PLACE
CENTRAL NC ON THE PERIPHERY OF THIS WEATHER SYSTEM. WEAK
PERTURBATIONS TRAVERSING EWD COUPLED WITH AVAILABLE MOISTURE AND
INSTABILITY SUGGEST A THREAT FOR SCATTERED SHOWERS AND STORMS EACH
DAY...MORE SO ON SATURDAY AFTERNOON AS A S/W IN THE NORTHERN STREAM
PROPELS A SFC FRONT SWD TOWARD CENTRAL NC. PLAN TO HAVE
CHANCE-SLIGHT CHANCE POPS NW-SE ACROSS THE REGION FRIDAY WITH HIGH
CHANCE POPS MOST LOCATIONS LATE SATURDAY-SATURDAY NIGHT.
SUNDAY INTO MONDAY....LATEST GFS HAS TRENDED TOWARD THE MORE
PROGRESSIVE ECMWF WHICH PUSHES THE SFC COLD FRONT SWD ACROSS CENTRAL
NC SUNDAY...AND POSITIONED SOUTH OF THE REGION MONDAY. THIS SUGGEST
A DECREASING THREAT FOR SCATTERED SHOWERS AND STORMS. PLAN TO
MAINTAIN MENTION OF A SMALL CHANCE BOTH DAYS...SUNDAY TO ACCOUNT FOR
POSSIBLE MODEL TIMING ISSUES WITH THE FRONTAL PASSAGE...AND ON
MONDAY AS DEVELOPING NW FLOW ALOFT MAY PROVIDE AN AVENUE FOR
DISTURBANCES ROTATING AROUND A DEEP CLOSED UPPER LOW OVER THE
NORTHERN LAKES TO TRANSLATE INTO OUR REGION.
TEMPS THURSDAY THROUGH MONDAY DEPENDENT UPON EXTENT OF CLOUD COVER
AND AREAL COVERAGE OF CONVECTION. EXPECT AFTERNOON TEMPS TO AVERAGE
A COUPLE OF DEGREES BELOW NORMAL WHILE OVERNIGHT TEMPS WILL BE 3-5
DEGREES ABOVE NORMAL.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 145 AM TUESDAY...
SHOWERS CONTINUE TO DEVELOP WEST OVER THE WESTERN PIEDMONT AND
FOOTHILLS WHERE WEAK WARM ADVECTION AND UPSLOPE FLOW IS MORE
PROMINENT...BUT THE TREND HAS BEEN FOR THE SHOWERS TO DISSIPATE AS
THEY DRIFT EAST NEAR KINT/KGSO. HIGH PRESSURE OFF THE MID-ATLANTIC
COAST IS FORECAST TO REMAIN RELATIVELY STATIONARY TODAY...WITH
LITTLE CHANGE IN THE FLOW OVER CENTRAL NC. THUS...MOISTURE WILL
CONTINUE TO BE BEST OVER WESTERN NC AND SHOWERS OR STORMS WILL
STRUGGLE TO MOVE ACROSS THE PIEDMONT. FORECAST SOUNDINGS SHOW
CEILINGS IN THE 3000-5000 FT RANGE TODAY...ALTHOUGH MVFR CEILINGS
CERTAINLY WILL BE POSSIBLE AT KGSO AND KINT.
OUTLOOK...
EARLY MORNING STRATUS WILL BE A PROBLEM EACH MORNING THIS
WEEK AS A MOIST SOUTHERLY FLOW PERSISTS. THE CHANCE OF SHOWERS AND
STORMS WILL EXIST EACH DAY...PARTICULARLY OVER WESTERN NC. THE
WEATHER WILL BECOME MORE UNSETTLED BY THE END OF THE WEEK AS A COLD
FRONT MOVES INTO THE REGION.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BSD
NEAR TERM...BSD/VINCENT
SHORT TERM..WSS
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
903 PM CDT WED AUG 7 2013
.UPDATE...
ISSUED AT 903 PM CDT WED AUG 7 2013
MAIN UPDATE WAS TO REMOVE MENTION OF THUNDER FOR ALL BUT THE
SOUTHWEST UNTIL MIDNIGHT...THEN REMOVE THUNDER ALTOGETHER. LATEST
WATER VAPOR IMAGERY SHOWED A SHORTWAVE NOW OVER WESTERN NORTH
DAKOTA...WITH A NARROW BAND OF LIFT/RAIN SHOWERS SOUTH OF HIGHWAY
2...FROM NEAR NEW TOWN EAST TO HARVEY. THIS AREA WAS CONTINUING TO
SAG SOUTH WHILE CONTINUING TO ADVANCE EAST. LOCAL RADAR WAS ALSO
SHOWING A WEAK LINE OF SHOWERS EXTENDING FROM GARRISON SOUTH TO
BISMARCK. SPC MESO-ANALYSIS SHOWS MID LEVEL LAPSE RATES INCREASING
IN RESPONSE TO THE SHORTWAVE IN WESTERN NORTH DAKOTA. WITH 50KT
0-6KM SHEAR IN THE SOUTHWEST...WILL CONTINUE TO MENTION ISOLATED
THUNDERSTORMS. A LACK OF INSTABILITY ELSEWHERE WILL INHIBIT ANY
THREAT OF THUNDERSTORMS. THE RAP AND 00Z NAM MAINTAIN THE IDEA THAT
ISOLATED SHOWERS WILL CONTINUE TO PUSH SOUTH TO THE BORDER THROUGH
12Z THURSDAY. CONCUR WITH THIS IDEA BASED ON THE POSITION AND
MOVEMENT OF THE AFOREMENTIONED SHORTWAVE. MINOR UPDATES TO
POPS/SKY/WX AND HOURLY TEMPERATURES.
UPDATE ISSUED AT 542 PM CDT WED AUG 7 2013
LATEST WATER VAPOR IMAGERY SHOWS A SHORTWAVE NOW WORKING ITS WAY
INTO NORTHEAST MONTANA FROM SOUTHERN SASKATCHEWAN. AN AREA OF RAIN
SHOWERS CONTINUE TO MOVE INTO NORTHWEST NORTH DAKOTA. THE LATEST
RAP HAS A GOOD READ ON THE ACTIVITY AS SCOOTS IT ACROSS THE NORTH
CENTRAL THIS EVENING. IN ADDITION...WILL WATCH FOR SHOWERS TO
DEVELOP IN THE WEST AND SOUTH CENTRAL EARLY TONIGHT PER RAP MODEL.
RADAR SHOWING A WEAK LINE TRYING TO GENERATE FROM NEAR WILLISTON
SOUTH TO TROTTERS AT THIS MOMENT. BEST FORCING REMAINS NORTH. THUS
WILL CONTINUE WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NORTH
THIS EVENING AND ISOLATED SHOWERS/THUNDERSTORMS WEST AND CENTRAL
OVERNIGHT. GIVEN THE WEAK INSTABILITY...THUNDER SHOULD REMAIN
ISOLATED. MINOR UPDATES TO HOURLY TEMPS/DEWPOINTS AND CHANGED
UNCERTAINTY WORDING TO AREAL COVERAGE IN THE WEATHER GROUP BASED
ON RADAR.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CURRENTLY...A STRONG UPPER LEVEL JET AND A SHORTWAVE IMPULSE
TRACKING ACROSS SOUTHERN SASKATCHEWAN IS RESPONSIBLE FOR PRODUCING
SCATTERED SHOWERS FROM NORTHEAST MONTANA INTO NORTHWEST NORTH
DAKOTA. THE SHOWERS ARE EXPECTED TO TRACK EAST AND SOUTH ACROSS
THE AREA LATE THIS AFTERNOON AND THIS EVENING. SIMILAR TO THE
TRACK OF A SHORTWAVE YESTERDAY. THE MAIN DIFFERENCE IS THE
ATMOSPHERE IS MORE STABLE TODAY. HOWEVER...WITH A STRONG UPPER
LEVEL JET AND SHORTWAVE...WE CANNOT RULE OUT A FEW THUNDERSTORMS
THIS AFTERNOON AND EARLY EVENING...WITH SMALL HAIL AND GUSTY
WINDS. HOWEVER IN THE FORECAST WE LIMITED THE BEST CHANCES TO THE
NORTH LATE THIS AFTERNOON...AND WITH LIMITED INSTABILITY AND
CAPPING ALOFT...WE KEPT A MENTION OF SHOWERS WITH ONLY ISOLATED
THUNDERSTORMS. EXPECT PRECIPITATION CHANCES TO DIMINISH AS THE
SYSTEM TRACKS SOUTHEAST. BUT THE LATEST RAP AND HRRR HOLD
REFLECTIVITIES TOGETHER AS THEY TRACK INTO THE SOUTHEAST CWA
AROUND MIDNIGHT.
MODELS HAVE TRENDED FARTHER SOUTH WITH THE NEXT WAVE COMING INTO
THE AREA AFTER MIDNIGHT. HAVE THEREFORE CONTINUED THE TREND OF
LOWERING POPS ACROSS THE AREA. CURRENTLY HAVE CHANCE POPS ACROSS
THE FAR SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT...AND HAVE
DROPPED POPS ACROSS THE SOUTH ON THURSDAY MORNING. ANOTHER
SHORTWAVE MOVING ACROSS ALBERTA TONIGHT WILL DROP SOUTHEAST INTO
THE LOCAL AREA THURSDAY AFTERNOON. THIS COULD DEVELOP AN ISOLATED
SHOWERS ACROSS THE NORTH DURING THE AFTERNOON. TEMPERATURES WILL
REMAIN ON THE COOL SIDE WITH HIGHS RANGING FROM THE 60S NORTH TO
THE 70S SOUTH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CONTINUED BELOW NORMAL TEMPERATURES WILL HIGHLIGHT THE EXTENDED
FORECAST.
AS HAS BEEN THE PATTERN OVER THE LAST COUPLE WEEKS...NORTHWEST
FLOW ALOFT WILL CONTINUE ACROSS THE NORTHERN PLAINS THROUGH THE
EXTENDED. THIS FAVORS BELOW NORMAL TEMPERATURES WITH HIGHS
GENERALLY IN THE 70S...PERHAPS RECOVERING INTO THE LOWER 80S BY
MID NEXT WEEK. OVERALL...THE COOLER EDGE OF GUIDANCE HAS BEEN
HANDLING THIS PATTERN BETTER...AND THUS UTILIZED A BLEND OF THE
BIAS CORRECTED 12 UTC SUITE. IN REGARDS TO PRECIPITATION...WHILE
ISOLATED DIURNAL CONVECTION IS HARD TO RULE OUT ANY DAY UNDER
NORTHWEST FLOW...THE FAVORED PERIODS FOR PRECIPITATION ARE SATURDAY
WITH LEE SURFACE LOW PRESSURE AND AGAIN TUESDAY INTO WEDNESDAY AS
PACIFIC ENERGY CRESTS THE UPPER LEVEL INTERMOUNTAIN WEST RIDGE AND
PROPAGATES INTO THE NORTHERN PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 542 PM CDT WED AUG 7 2013
SCT/BKN LOW VFR CIGS WILL CONTINUE THROUGH THE TAF PERIOD UNDER A
NORTHWEST UPPER FLOW AND A COUPLE OF UPPER AIR DISTURBANCES
RESULTING IN A VCSH MENTION AT KISN/KMOT/KJMS. COULD BE PATCHY FOG
DEVELOPING FOR A SHORT PERIOD TOWARD 12Z THURSDAY AT KMOT. WILL
MONITOR SATELLITE AND SURFACE OBSERVATIONS BEFORE MENTIONING A
PREDOMINATE GROUP IN THE FORECAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...KS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1131 PM CDT MON AUG 5 2013
.UPDATE...
ISSUED AT 1125 PM CDT MON AUG 5 2013
MAIN QUESTION IS HOW MUCH PRECIP WILL MAKE IT THIS FAR EAST LATER
TONIGHT INTO TUESDAY. BIG MCS NOW IN SOUTHERN KANSAS AND LACK OF
ANY STRONG LOW LEVEL MOISTURE ADVECTION AND WEAK 850 MB JET IS
CAUSING A LOT OF THE ACTIVITY FROM SASK INTO WRN ND TO WEAKEN.
CANADAIAN RADARS SHOW THIS TOO. BUT VORT IS PRETTY STRONG SO DO
FORSEE SOME ACTIVITY TO MAKE IT IN AS FCST OVERNIGHT. 00Z MODELS
AND LATEST HRRR COMING AROUND TO THE IDEA OF A WEAK SFC LOW NR
WILLISTON MOVING SOUTHEAST TO NEAR FARGO AREA BY 16Z TUE WITH
WINDS TURNING NORTHWEST AND NORTH BEHIND IT. 00Z GFS ACTUALLY NOT
BAD WITH QPF THIS RUN....OTHER MODELS TOO MUCH.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 321 PM CDT MON AUG 5 2013
WITH THE CLOUDS CONTINUING TO PUSH EAST SLOWLY ANY CLEARING WILL
BE RELATIVELY SHORT LIVED. CONVECTION STARTING UP OVER EASTERN MT
WILL BEGIN SPREADING IN SOME HIGHER LEVEL CLOUDS TONIGHT. THE MAIN
FORECAST CONCERN WILL SHIFT BACK TO TIMING THE NEXT CHANCE OF PCPN
FOR LATER TONIGHT INTO TUE/TUE NIGHT. TRIED TO FOLLOW THE HIGH RES
MODELS FOR THE ARRIVAL TIME OF PCPN TONIGHT AND THEN KIND OF A
BLEND FOR TIMING THE BEST CHANCES FROM WEST TO EAST THRU TUE. SPC
HAS SOUTHWEST ND AND WESTERN SD IN A SLIGHT RISK FOR DAY1. THIS IS
THE AREA ONCE AGAIN WHICH HAS HEATED OUT WITH SLIGHTLY HIGHER DEW
POINTS. RESULTANT MLCAPE VALUES ARE PUSHING TO AROUND 1500J/KG
WITH DECENT SHEAR ALSO PRESENT. SO ONCE AGAIN THE CONVECTION IS
FIRING WEST OF THE FA. THE NEXT DECENT UPSTREAM SHORT WAVE IS
DROPPING INTO NORTHWEST MT. THIS WAVE WILL BEGIN AN EASTWARD
SHIFT TAKING IT INTO EASTERN MT/WESTERN ND BY 06Z THEN CENTRAL ND
BY 12Z. THEREFORE IT SEEMS REASONABLE THAT SOME LINGERING
CONVECTION THAT FIRES OUT WEST MAY HOLD TOGETHER AS IT TRACKS INTO
THE FA LATE. ANOTHER AREA THAT WILL BEAR WATCHING IS A COLD FRONT
UP IN THE MANITOBA LAKES REGION NORTH OF WINNIPEG. AS THE WESTERN
WAVE APPROACHES CENTRAL ND BY 12Z TUE IT WILL HELP ORGANIZE A WEAK
SFC LOW IN THIS SAME GENERAL VICINITY. THE COLD FRONT SHOULD GET
DRAWN DOWN INTO THE NORTHERN FA BY 12Z. THE HIGH RES MODELS SHOW
THE POTENTIAL FOR SOME PCPN ALONG THIS BOUNDARY TOO. SOME WEAK
WARM ADVECTION AND LOW LEVEL JET ENERGY MAY ALSO COME INTO PLAY
AFTER DARK TOO...FEEDING INTO CENTRAL ND IN THE LATE EVENING.
ALL OF THE ABOVE MENTIONED FEATURES KIND OF MELD OVER THE FA ON
TUE WITH THE COLD FRONT SLOWLY SLIDING FROM NORTH TO SOUTH AND THE
SHORT WAVE FROM WEST TO EAST. KEPT LIKELY CHANCES FOR PCPN AND
TRIED TO BREAK THEM OUT TO SHOW THE WEST TO EAST PROGRESS THRU THE
DAY. SPC DAY2 HAS A SLIGHT RISK JUST TO THE SOUTH OF THE FA SO HOW
FAST THE FRONT DROPS SOUTH WILL LIKELY DETERMINE IF ANY TSTMS CAN
BECOME STRONG TO SEVERE ACROSS THE FAR SOUTH TUE AFTERNOON. STILL
EXPECT ANY LINGERING PCPN TO EXIT THE EAST TUE EVENING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 321 PM CDT MON AUG 5 2013
KEPT WED PCPN FREE WITH THE NEXT PCPN CHANCES COMING WED NIGHT
INTO THU. PRETTY MUCH LEFT THE PCPN CHANCES FOR THIS NEXT EVENT AS
IS FOR NOW.
FRIDAY TO MONDAY...MODEL AGREEMENT CONTINUES WITH THE SAME OLD
PATTERN OF CONFLUENT NW FLOW AT 500MB...WHICH MEANS DRY AND
SLIGHTLY COOLER THAN NORMAL FOR THE NORTHERN PLAINS. THERE REMAINS
A CHANCE FOR SOME SHOWER ACTIVITY AT SOME POINT OVER THE NEXT
WEEKEND BUT WITH UNCERTAINTY IN TIMING AND SMALL AREAL COVERAGE
THAT A WEAK WAVE MAY INDUCED PRECIP...HAVE KEPT THE MAJORITY OF
THE CWFA COMPLETELY DRY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1125 PM CDT MON AUG 5 2013
HIGH CLOUDS SPREADING ACROSS THE AREA ATTM...AND QUESTION WILL BE
TIMING ANY SHOWERS. THUNDER THREAT IS WEAKENING AND SHOULD BE
ISOLD OVERNIGHT INTO TUESDAY MORNING. EXPECT SHOWERS TO COME FROM
BASES AOA 6000 FT AGL AS SYSTEM MOVES THROUGH. WINDS TURN NORTH-
NORTHWEST TUESDAY MORNING IN DVL REGION THEN REACHING SE
ND/WCNTRL MN TUES EARLY-MID AFTN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...GODON
LONG TERM...GODON/JK
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
911 PM EDT WED AUG 7 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH INTO THE REGION TONIGHT AND THURSDAY.
THE FRONT WILL EVENTUALLY STALL CLOSE TO THE OHIO RIVER BY FRIDAY
MORNING. THIS FRONTAL BOUNDARY WILL THEN OSCILLATE NEAR THE OHIO
RIVER THROUGH THE WEEKEND. THE THREAT OF SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THE PERIOD...ESPECIALLY FOR THOSE LOCATIONS
CLOSER TO THE FRONTAL BOUNDARY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
HAVE UPDATED PRIMARILY TO ACCOUNT FOR SHOWERS AND THUNDERSTORMS
OVER PORTIONS OF NORTHERN KENTUCKY SOUTH OF METRO CINCINNATI. A
WEAK INFLECTION RUNNING ALONG BUT JUST SOUTHEAST OF THE I-71
CORRIDOR MAY HAVE AN ENHANCED POTENTIAL FOR SHOWERS THIS EVENING
BUT ONLY FOR THE NEXT HOUR OR TWO. UPSTREAM STORMS OVER INDIANA DO
NOT POSE A THREAT TO US IN THE NEXT 3-5 HOURS AND THE STORMS OVER
KY WILL BE DYING OUT AS THEY SLOWLY MOVE ENE. BLENDED INTO THE
30ISH POPS TOWARDS DAYBREAK THAT WERE IN EARLIER FORECAST AND
TRIED TO PLAY DOWN THE THREAT ELSEWHERE...AT LEAST FOR THE EARLY
PART OF THE OVERNIGHT.
HAVE USED A BLEND OF THE HRRR AND NAM FOR THE NEAR TERM FORECAST.
A COLD FRONT WAS POISED TO OUR NORTHWEST THIS EVENING. THIS FRONT
IS FORECAST TO SLOWLY SINK SOUTHEAST TOWARD THE AREA OVERNIGHT.
CURRENT THINKING IS THAT CONVECTIVE ACTIVITY NEAR THE FRONT WILL
DIMINISH THIS EVENING WITH THE LOSS OF DAYTIME HEATING AND
FORCING. LATEST MODEL RUNS NOW SUGGEST THAT SUBTLE LOW LEVEL JET
AND ASSOCIATED UPR LVL DISTURBANCE WILL LIKELY STAY TO OUR SOUTH
AND SOUTHWEST OVERNIGHT. AS A RESULT...WITH VERY WEAK
FORCING...CAN NOT SEE GOING MUCH HIGHER THAN 30 POPS FOR ALL
LOCATIONS. WILL UPDATE THE ZONES TO REFLECT THIS. WILL ALSO REMOVE
HEAVY RAIN THREAT GIVEN SPARSE COVERAGE. AMPLE LOW LEVEL MOISTURE
AND DIMINISHING WINDS WILL MAKE FOG AND/OR STRATUS A CONCERN AFTER
MIDNIGHT...ESPECIALLY IF HOLES CAN DEVELOP IN THE MID AND UPPER
LEVEL CLOUDS. WILL CONTINUE TO MENTION AREAS OF FOG IN THE ZONES
AFTER MIDNIGHT AS WELL AS IN THE HWO. LOWS WILL RANGE FROM THE
UPPER 60S NW TO THE LOWER 70S ELSEWHERE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE LOWER GREAT LAKES AND OHIO VALLEY REGION WILL BE BETWEEN A
LARGE ANOMALOUS UPR LVL LOW OVER ONTARIO AND A MID LVL SUBTROPICAL
RIDGE OVER THE SRN STATES THROUGH THE SHORT TERM PERIOD. THIS
SETUP WILL ONLY ALLOW AFOREMENTIONED FRONTAL SYSTEM TO MOVE EVER
SO SLOWLY TO SOUTHEAST...EVENTUALLY STALLING NEAR THE OHIO RIVER
BY FRIDAY MORNING AS MID LEVEL FLOW BECOMES ZONAL. THE FRONT WILL
PROVIDE THE FOCUS FOR SHOWERS AND STORMS THROUGH THE PERIOD...BUT
THE TIMING AND AREAL COVERAGE WILL BE PROBLEMATIC AS MODELS ARE
ESSENTIALLY OFFERING DIFFERENT SOLUTIONS. HAVE GONE WITH A
NAM/ECMWF BLEND WHICH IS FORECASTING A SLOWER FRONTAL MOVEMENT. AS
SUCH...THERE IS A HINT OF A FRONTAL WAVE RIPPLING ALONG THE FRONT
ON THURSDAY THROUGH THE HEART OF THE FORECAST AREA. THIS WAVE AND
ANY UPR LVL SUPPORT FROM AN ASSOCIATED DISTURBANCE OR MCV SHOULD
PROVIDE THE BEST CHANCE FOR SHOWERS AND STORMS ALONG AND SOUTHEAST
OF THE LOW. HAVE HIGHEST POPS MAINLY FOR POINTS ALONG AND
SOUTHEAST OF INTERSTATE 71 WITH THE DIURNAL CYCLE PLAYING A ROLE
IN TERMS OF BEST COVERAGE.
LOOKS LIKE WAVE MOVES OFF TO THE NORTHEAST THURSDAY NIGHT...WHICH
SHOULD RESULT IN A DOWN TICK IN SHOWER/THUNDERSTORMS COVERAGE IN
ITS WAKE.
THE AIRMASS WILL BE QUITE MOIST ALONG AND AHEAD OF THE FRONT WITH
PWATS OF 2 INCHES PLUS EXPECTED. IN ADDITION...WARM CLOUD DEPTHS
WILL BE CLOSE TO 4 KM WHICH WOULD FAVOR COLLISION/COALESCENCE
PROCESSES AND THE POTENTIAL FOR HEAVY RAIN. GIVEN THE UNCERTAINTY
IN PLACEMENT OF HEAVIEST RAIN WITH UPCOMING ROUNDS OF SHOWERS AND
STORMS...WILL CONTINUE TO HIGHLIGHT THE HEAVY RAIN THREAT/LOCAL
FLOODING ISSUES IN THE HWO WITH AN EMPHASIS PLACED ACRS THE SRN
CWFA CLOSER TO THE FRONTAL BOUNDARY.
HIGHS ON THURSDAY SHOULD BE HELD DOWN BY CLOUDS AND PCPN...WITH
LOWER TO MID 80S EXPECTED. LOWS THURSDAY NIGHT WILL RANGE FROM THE
MID 60S NW TO THE LOWER 70S SOUTH.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
MAIN FOCUS FOR THE FIRST PART OF THE EXTENDED PERIOD WILL BE A
SURFACE FRONTAL BOUNDARY THAT WILL ORIENT ITSELF ALONG THE OHIO
RIVER FRIDAY MORNING. WITH ZONAL FLOW ALOFT...THIS BOUNDARY WILL
VERY SLOWLY SAG SOUTHWARD THROUGH THE WEEKEND. ONE WAVE OF LOW
PRESSURE RIDING ALONG THE FRONT WILL BE EXITING TO THE NORTHEAST AT
THE START OF THE PERIOD...ONLY TO BE FOLLOWED BY ANOTHER RIPPLE
FRIDAY NIGHT INTO SATURDAY. SOUTHERN PORTIONS OF THE FA WILL SEE THE
GREATEST CHANCE FOR RAIN THROUGH THE WEEKEND AND LATEST
DETERMINISTIC RUNS CONTINUE TO INDICATE PW VALUES IN THE 150 TO 175
PERCENT OF NORMAL RANGE THERE THROUGH FRIDAY NIGHT. WITH SEVERAL
ROUNDS OF SHOWERS AND STORMS IN THE FORECAST...WILL CONTINUE TO
MONITOR THE POSSIBILITY OF SOME LOCALIZED FLOODING ACROSS THE SOUTH.
THE 12Z GFS AND ECMWF HAVE BOTH NUDGED QPF A TAD FURTHER SOUTH
FOR SATURDAY AND SUNDAY THAN THEY HAD IN EARLIER RUNS...SO OPTED TO
LOWER OR TAKE OUT POPS ACROSS THE NORTHERN HALF OF THE FA THROUGH
THE WEEKEND. KEPT CHANCE POPS IN ACROSS THE SOUTH WHILE THE FRONT
LINGERS NEAR THE OHIO RIVER. BY MONDAY A MID LEVEL TROUGH OVER
EASTERN CANADA WILL BEGIN TO AMPLIFY...RESULTING IN NW FLOW OVER THE
OHIO VALLEY BY THE MIDDLE OF NEXT WEEK. MEANWHILE SURFACE HIGH
PRESSURE WILL BUILD OVER THE GREAT LAKES WHICH SHOULD PROVIDE A
PERIOD OF DRIER WEATHER FOR TUESDAY AND WEDNESDAY. TEMPERATURES
THROUGH THE PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL WITH HIGHS
IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
COLD FRONT IS APPROACHING CWA THIS EVENING AND SHOULD BE IN THE
DAYTON VICINITY SHORTLY AFTER MIDNIGHT AND ALONG THE I-71 CORRIDOR
BY DAYBREAK. CU FIELD DID NOT HAVE ENOUGH DAYLIGHT AS IT TOOK TOO
LONG FOR THE STRATUS TO BREAK UP AND ONLY EASTERN AREAS OF CWA
OUTSIDE OF TAFS SAW ANY SHOWER/THUNDERSTORM ACTIVITY THIS
AFTERNOON. SOME STORMS ARE TRYING TO GET GOING SOUTH OF CINCINNATI
BUT WILL NOT RECEIVE THE BENEFIT OF DAYLIGHT TO HELP THEM CONTINUE
THIS EVENING AND ARE EXPECTED TO DIE OUT.
AS THE FRONT APPROACHES...SOME STORMS MAY OCCUR WITH THEM BUT THEY
SHOULD BE FEW AND FAR BETWEEN SO I LEFT THEM OUT OF THE TERMINAL
FORECASTS IN FAVOR OF UPDATING WHEN IT IS APPARENT THE TAF SITES
WILL BE AFFECTED. THIS HOLDS TRUE FOR EARLY TOMORROW AS WELL.
STRATUS IS EXPECTED AGAIN TONIGHT ESPECIALLY AS THERE IS NOT MUCH
IN THE LINES OF MID/HIGH CLOUDS AND THE LOWER ATMOSPHERE SHOULD
RADIATE NICELY. THINK THAT LIFR CIGS/VSBYS ARE POSSIBLE OVERNIGHT
IN ANY LOCATION BUT MORE LIKELY TOWARDS CINCINNATI METRO.
MODELS ARE NOT HANDLING THE AIRMASS WELL AND A LOT OF UNCERTAINTY
EXISTS IN TONIGHTS FORECAST AND WILL LIKELY EXTEND INTO THE NEXT
24-48 HOURS AS THE FRONT STALLS OVER THE REGION.
TIMING...PLACEMENT...AND EVEN OCCURRENCE ISSUES WILL ABOUND WITH
ANY STORMS THE NEXT FEW DAYS.
OUTLOOK...THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES
THROUGH FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...FRANKS/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...KURZ
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
713 PM EDT WED AUG 7 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH INTO THE REGION TONIGHT AND THURSDAY.
THE FRONT WILL EVENTUALLY STALL CLOSE TO THE OHIO RIVER BY FRIDAY
MORNING. THIS FRONTAL BOUNDARY WILL THEN OSCILLATE NEAR THE OHIO
RIVER THROUGH THE WEEKEND. THE THREAT OF SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THE PERIOD...ESPECIALLY FOR THOSE LOCATIONS
CLOSER TO THE FRONTAL BOUNDARY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
HAVE USED A BLEND OF THE HRRR AND NAM FOR THE NEAR TERM FORECAST.
A COLD FRONT WAS POISED TO OUR NORTHWEST THIS EVENING. THIS FRONT
IS FORECAST TO SLOWLY SINK SOUTHEAST TOWARD THE AREA OVERNIGHT.
CURRENT THINKING IS THAT CONVECTIVE ACTIVITY NEAR THE FRONT WILL
DIMINISH THIS EVENING WITH THE LOSS OF DAYTIME HEATING AND
FORCING. LATEST MODEL RUNS NOW SUGGEST THAT SUBTLE LOW LEVEL JET
AND ASSOCIATED UPR LVL DISTURBANCE WILL LIKELY STAY TO OUR SOUTH
AND SOUTHWEST OVERNIGHT. AS A RESULT...WITH VERY WEAK
FORCING...CAN NOT SEE GOING MUCH HIGHER THAN 30 POPS FOR ALL
LOCATIONS. WILL UPDATE THE ZONES TO REFLECT THIS. WILL ALSO REMOVE
HEAVY RAIN THREAT GIVEN SPARSE COVERAGE. AMPLE LOW LEVEL MOISTURE
AND DIMINISHING WINDS WILL MAKE FOG AND/OR STRATUS A CONCERN AFTER
MIDNIGHT...ESPECIALLY IF HOLES CAN DEVELOP IN THE MID AND UPPER
LEVEL CLOUDS. WILL CONTINUE TO MENTION AREAS OF FOG IN THE ZONES
AFTER MIDNIGHT AS WELL AS IN THE HWO. LOWS WILL RANGE FROM THE
UPPER 60S NW TO THE LOWER 70S ELSEWHERE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE LOWER GREAT LAKES AND OHIO VALLEY REGION WILL BE BETWEEN A
LARGE ANOMALOUS UPR LVL LOW OVER ONTARIO AND A MID LVL SUBTROPICAL
RIDGE OVER THE SRN STATES THROUGH THE SHORT TERM PERIOD. THIS
SETUP WILL ONLY ALLOW AFOREMENTIONED FRONTAL SYSTEM TO MOVE EVER
SO SLOWLY TO SOUTHEAST...EVENTUALLY STALLING NEAR THE OHIO RIVER
BY FRIDAY MORNING AS MID LEVEL FLOW BECOMES ZONAL. THE FRONT WILL
PROVIDE THE FOCUS FOR SHOWERS AND STORMS THROUGH THE PERIOD...BUT
THE TIMING AND AREAL COVERAGE WILL BE PROBLEMATIC AS MODELS ARE
ESSENTIALLY OFFERING DIFFERENT SOLUTIONS. HAVE GONE WITH A
NAM/ECMWF BLEND WHICH IS FORECASTING A SLOWER FRONTAL MOVEMENT. AS
SUCH...THERE IS A HINT OF A FRONTAL WAVE RIPPLING ALONG THE FRONT
ON THURSDAY THROUGH THE HEART OF THE FORECAST AREA. THIS WAVE AND
ANY UPR LVL SUPPORT FROM AN ASSOCIATED DISTURBANCE OR MCV SHOULD
PROVIDE THE BEST CHANCE FOR SHOWERS AND STORMS ALONG AND SOUTHEAST
OF THE LOW. HAVE HIGHEST POPS MAINLY FOR POINTS ALONG AND
SOUTHEAST OF INTERSTATE 71 WITH THE DIURNAL CYCLE PLAYING A ROLE
IN TERMS OF BEST COVERAGE.
LOOKS LIKE WAVE MOVES OFF TO THE NORTHEAST THURSDAY NIGHT...WHICH
SHOULD RESULT IN A DOWN TICK IN SHOWER/THUNDERSTORMS COVERAGE IN
ITS WAKE.
THE AIRMASS WILL BE QUITE MOIST ALONG AND AHEAD OF THE FRONT WITH
PWATS OF 2 INCHES PLUS EXPECTED. IN ADDITION...WARM CLOUD DEPTHS
WILL BE CLOSE TO 4 KM WHICH WOULD FAVOR COLLISION/COALESCENCE
PROCESSES AND THE POTENTIAL FOR HEAVY RAIN. GIVEN THE UNCERTAINTY
IN PLACEMENT OF HEAVIEST RAIN WITH UPCOMING ROUNDS OF SHOWERS AND
STORMS...WILL CONTINUE TO HIGHLIGHT THE HEAVY RAIN THREAT/LOCAL
FLOODING ISSUES IN THE HWO WITH AN EMPHASIS PLACED ACRS THE SRN
CWFA CLOSER TO THE FRONTAL BOUNDARY.
HIGHS ON THURSDAY SHOULD BE HELD DOWN BY CLOUDS AND PCPN...WITH
LOWER TO MID 80S EXPECTED. LOWS THURSDAY NIGHT WILL RANGE FROM THE
MID 60S NW TO THE LOWER 70S SOUTH.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
MAIN FOCUS FOR THE FIRST PART OF THE EXTENDED PERIOD WILL BE A
SURFACE FRONTAL BOUNDARY THAT WILL ORIENT ITSELF ALONG THE OHIO
RIVER FRIDAY MORNING. WITH ZONAL FLOW ALOFT...THIS BOUNDARY WILL
VERY SLOWLY SAG SOUTHWARD THROUGH THE WEEKEND. ONE WAVE OF LOW
PRESSURE RIDING ALONG THE FRONT WILL BE EXITING TO THE NORTHEAST AT
THE START OF THE PERIOD...ONLY TO BE FOLLOWED BY ANOTHER RIPPLE
FRIDAY NIGHT INTO SATURDAY. SOUTHERN PORTIONS OF THE FA WILL SEE THE
GREATEST CHANCE FOR RAIN THROUGH THE WEEKEND AND LATEST
DETERMINISTIC RUNS CONTINUE TO INDICATE PW VALUES IN THE 150 TO 175
PERCENT OF NORMAL RANGE THERE THROUGH FRIDAY NIGHT. WITH SEVERAL
ROUNDS OF SHOWERS AND STORMS IN THE FORECAST...WILL CONTINUE TO
MONITOR THE POSSIBILITY OF SOME LOCALIZED FLOODING ACROSS THE SOUTH.
THE 12Z GFS AND ECMWF HAVE BOTH NUDGED QPF A TAD FURTHER SOUTH
FOR SATURDAY AND SUNDAY THAN THEY HAD IN EARLIER RUNS...SO OPTED TO
LOWER OR TAKE OUT POPS ACROSS THE NORTHERN HALF OF THE FA THROUGH
THE WEEKEND. KEPT CHANCE POPS IN ACROSS THE SOUTH WHILE THE FRONT
LINGERS NEAR THE OHIO RIVER. BY MONDAY A MID LEVEL TROUGH OVER
EASTERN CANADA WILL BEGIN TO AMPLIFY...RESULTING IN NW FLOW OVER THE
OHIO VALLEY BY THE MIDDLE OF NEXT WEEK. MEANWHILE SURFACE HIGH
PRESSURE WILL BUILD OVER THE GREAT LAKES WHICH SHOULD PROVIDE A
PERIOD OF DRIER WEATHER FOR TUESDAY AND WEDNESDAY. TEMPERATURES
THROUGH THE PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL WITH HIGHS
IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
STUBBORN STRATUS AND FOG THAT AFFECTED THE MAJORITY OF THE TAFS THIS
MORNING HAS FINALLY LIFTED TO VFR. IT HAS LIMITED THE INSTABILITY
SO FAR...BUT LATEST RADAR LOOP IS SHOWING SOME DEVELOPMENT ACROSS
THE WRN TAFS...WITH SLIGHTLY BETTER INSTABILITY JUST TO THEIR E.
POP UP CONVECTION WILL BE POSSIBLE THOUGH THE AFTN HOURS DUE TO
THE HEATING OF THE DAY. EXPECT A LULL BETWEEN 00-06Z...BEFORE
ANOTHER CHANCE OF CONVECTION AFT 06Z...ASSOCIATED WITH A CDFNT
THAT IS SCHEDULED TO PUSH IN AFT 06Z. WENT WITH JUST A VCTS DUE TO
THE UNCERTAINTY OVERNIGHT. AM CONCERNED ABOUT THE REDEVELOPMENT OF
MVFR/IFR ST AND FOG LATE AFT 09Z. WENT WITH MVFR CONDITIONS IN THE
TAFS...BUT SOME LOWER CONDITIONS ARE POSSIBLE. EXPECT THE ST TO
LINGER INTO LATE MORNING LIKE IT DID THIS MORNING.
OUTLOOK...THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES
THROUGH FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...KURZ
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
101 PM EDT TUE AUG 6 2013
.SYNOPSIS...
INSTABILITY INCREASES LATE TODAY AND OVERNIGHT. STRONGER MID LEVEL
DISTURBANCE PASSES WEDNESDAY. MORE ROUNDS OF CONVECTION INTO THIS
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONCE YOU GET SPOILED BY THOSE RARE LOWER DEW POINTS IN THE DOG DAYS
OF SUMMER...YOU HATE TO SEE THEM LEAVE. THE INITIAL MID LEVEL
DISTURBANCE WAS CROSSING THE CENTRAL WV MOUNTAINS THIS EARLY HOUR OF
08Z. A SECONDARY 500 MB VORT IS INDICATED ON THE 07Z RAP MODEL
PASSING N OF BKW AROUND 09-10Z.
MEANWHILE...WHILE THE MID LEVEL MOISTURE INCREASED FROM THE WEST
LAST NIGHT...THE LOWER LEVEL MOISTURE MADE ITS FASTEST INITIAL
CHARGE NORTH...ON THE EASTERN SLOPES OF THE APPALACHIANS. YET...THE
925 TO 850 MB FLOW REMAINS WEAK AND STARTS VEERING MORE TOWARD SOUTH
AND SOUTHWEST. SO TOUGH CLOUD FORECAST TODAY FOR AREAS FROM BKW EAST
INTO THE UPPER GREENBRIER VALLEY.
MEANWHILE...IN THE WAKE OF THE MID LEVEL DISTURBANCE...BREAKS IN THE
CLOUDS COULD YIELD SOME BRIEF FOG IN THE MID OHIO VALLEY FOR DAWN.
NO MAJOR CHANGES TODAY...KEPT A 20/30 POPS OVER THE MOUNTAINS FOR
THE AFTERNOON HEATING IN THE WEAK FLOW. ALSO KEPT THE POSSIBILITY
OF CONVECTION FORMING FOR OUR NE KENTUCKY AND THE TRI STATE AROUND
HTS AFTER 18Z.
MOST MODELS LIKE THE ECMWF...GFS HOLD US DRY OVERNIGHT. BUT NAM
SHOWS MINOR FEATURES WITH INCREASING LOW LEVEL WINDS/FORCING AT
925 MB TO 850 MBS. IT IS TOO PREMATURE TO REMOVE POPS IN OUR
SOUTHERN AND WESTERN COUNTIES FOR TONIGHT. I DID TRY TO HOLD THE
ROUTE 50 CORRIDOR INCLUDING PKB TO CKB DRY MOST OF THE NIGHT. HAVE
POPS INCREASING INTO THE 30 TO 40 PERCENT RANGE ACROSS THE SOUTH
OVERNIGHT. CERTAINLY THE LONGER WE CAN HOLD OFF AREAS OF HEAVIER
CONVECTION THE BETTER...CONSIDERING THE ACTIVE PATTERN INTO THIS
WEEKEND.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
NEW 00Z MODELS LEAVE SOME QUESTION TO HOW THINGS WILL PLAY OUT
THROUGH THE SHORT TERM...AS ECMWF HAS MOVED BEST UPPER LEVEL SUPPORT
FARTHER NORTH WHILE NAM/GFS HAVE BEEN FAIRLY CONSISTENT WITH
PREVIOUS RUNS LOCATION WISE. ALL MODELS HAVE SLOWED DOWN A BIT WITH
THE PRECIP FOR WEDNESDAY...SO TRENDED THAT WAY. DESPITE THE MODEL
DIFFERENCES...THUNDERSTORMS LIKELY WEDNESDAY INTO WEDNESDAY NIGHT
AND WITH PW VALUES CLIMBING ABOVE 2 INCHES HEAVY RAIN IS ALSO
LIKELY. TRAIN OF VORT MAXES CONTINUES AS COLD FRONT APPROACHES
THURSDAY THROUGH FRIDAY. GFS STILL SHOWS THE COLD FRONT TRYING TO
PUSH THROUGH FRIDAY NIGHT...HOWEVER NEW ECMWF STALLS THE SURFACE
FRONT NEAR TO JUST NORTH OF CWA. THINK THE ECMWF MAY BE ON TO
SOMETHING...BUT WITH THIS BEING THE FIRST INDICATION...WON/T JUMP
FULLY ON IT YET. DID INCREASE LOWS FRIDAY NIGHT QUITE A BIT...WITH
ONLY MINIMAL CHANGES MADE TO OTHER TEMPS.
WILL CONTINUE WATER CONCERN MENTION IN HWO. THINK MOST LOCATIONS
SHOULD BE ABLE TO HANDLE WEDNESDAYS BATCH OF HEAVY RAIN SINCE WE
HAVE HAD SOME TIME TO DRY OUT SINCE LAST SIGNIFICANT RAIN...SO AM
MORE CONCERNED WITH REPETITIVE STORMS ADDING UP THROUGH THE END OF
THE WEEK. WITH THAT SAID...CAN NOT RULE OUT LOCALIZED ISSUES
WEDNESDAY DUE TO DOWNPOURS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
GENERALLY USED WPC THINKING FOR THIS PORTION OF THE FORECAST.
HOWEVER...HAVE MADE SOME CHANGES TO REFLECT DIFFERENCES IN LATEST
MODEL GUIDANCE.
WPC INDICATES A COLD FRONT SHOULD BE LOCATED JUST TO OUR NORTHWEST
EARLY IN THE PERIOD. THE COLD FRONT WILL PUSH SOUTHEAST SATURDAY AND
SATURDAY NIGHT. SEVERAL MID-LEVEL SHORTWAVES AND A WEAK AREA OF LOW
PRESSURE WILL THEN PUSH EAST MONDAY INTO TUESDAY.
LATEST GFS IS SLOWER WITH THE SOUTHEAST PROGRESS OF THE COLD
FRONT. WITH THIS IN MIND...HAVE HELD ONTO LOW POPS A LITTLE LONGER
FOR SATURDAY NIGHT INTO SUNDAY.
LOWERED HPC TEMP NUMBERS A FEW DEGREES AS THEY APPEAR TOO WARM FOR
THE EXPECTED CONDITIONS.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
THE MID LEVEL DISTURBANCE CROSSING THE WV MOUNTAINS BETWEEN EKN AND
BKW AT 10Z. WITH BREAKS IN THE CLOUDS IN ITS WAKE...AREAS OF
IFR/LIFR IN FOG FORMING LATE...IN WAKE OF THE RAIN SHOWERS...FROM
EASTERN OHIO ACROSS NORTHERN WEST VIRGINIA INCLUDING PKB TO
CKB...AND EVEN TOWARD W22 AND EKN...FOR A BRIEF TIME AROUND 10Z TO
12Z. MAINLY MVFR IN FOG FURTHER SOUTH TOWARD CRW AND THE SOUTHERN
WV COAL FIELDS.
THE UPSLOPE FLOW ALONG THE EASTERN SLOPES OF THE APPALACHIANS
IS WEAK AND BECOMES MORE SOUTHERLY BY MIDDAY TODAY. THIS LOWERS MY
CONFIDENCE IN THE CEILINGS ALONG THE SPINE OF THE APPALACHIANS ON
EAST INTO THE GREENBRIER VALLEY. BECKLEY IN THE SOUTHERN MOUNTAINS
MAY BE ON THE WESTERN FRINGE OF THIS MAXIMUM IN LOW LEVEL MOISTURE
THIS MORNING...SO HAVE A SCATTERED TO BROKEN DECK THERE AROUND 2
THSD FT AGL.
IN DAYTIME HEATING HAVE SCATTERED TO BROKEN CLOUDS MOSTLY 2 TO 4
THSD FT AGL EXCEPT 4 TO 6 THSD FT ACROSS NORTHERN WV LOWLANDS.
A FEW SHOWERS OR THUNDERSTORMS COULD FORM IN THE AFTERNOON HEATING
OVER THE MOUNTAINOUS COUNTIES. INSTABILITY INCREASES IN THE TRI
STATE VCNTY OF HTS BY 21Z INCLUDING EASTERN KENTUCKY...SO SOME
THUNDERSTORMS COULD DEVELOP THERE LATE TODAY AND LINGER TONIGHT.
WITH MOISTURE INCREASING AT 850 MB AND BELOW WEST OF THE MOUNTAINS
TONIGHT...HAVE MORE WIDESPREAD CEILINGS A 3 TO 4 THSD FT DEVELOPING
00Z TO 06Z WEDNESDAY IN THE WESTERN LOWLANDS. VSBY COULD BE 5 TO 6
MILES IN HAZE WITH INCREASING SURFACE DEW POINTS. INSTABILITY
LINGERS OVERNIGHT...SO HAVE CHANCE POPS FOR CONVECTION CREEPING NE
INTO CENTRAL WV AND CRW VCNTY. EXPECTING DRY CONDITIONS TO HOLD
PKB TO CKB VCNTY OVERNIGHT THRU 12Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: EARLY MORNING FOG IN WAKE OF THE RAIN COULD
LINGER AN HOUR LONGER. COVERAGE AND TIMING OF ANY OVERNIGHT CONVECTION
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M M H H H H H H H H H H
HTS CONSISTENCY M M H H H H H H H H H H
BKW CONSISTENCY M M M M M M H H H H M M
EKN CONSISTENCY L M M H H H H H H H H H
PKB CONSISTENCY L L H H H H H H H H H H
CKB CONSISTENCY L L H H H H H H H H H H
AFTER 18Z WEDNESDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION WEDNESDAY INTO SATURDAY. IN HUMID
AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...
ESPECIALLY AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
556 AM EDT TUE AUG 6 2013
.SYNOPSIS...
WEAK DISTURBANCE EXITS THE MOUNTAIN COUNTIES THIS MORNING. INSTABILITY
INCREASES LATE TODAY AND OVERNIGHT. STRONGER MID LEVEL DISTURBANCE
PASSES WEDNESDAY. MORE ROUNDS OF CONVECTION INTO THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONCE YOU GET SPOILED BY THOSE RARE LOWER DEW POINTS IN THE DOG DAYS
OF SUMMER...YOU HATE TO SEE THEM LEAVE. THE INITIAL MID LEVEL
DISTURBANCE WAS CROSSING THE CENTRAL WV MOUNTAINS THIS EARLY HOUR OF
08Z. A SECONDARY 500 MB VORT IS INDICATED ON THE 07Z RAP MODEL
PASSING N OF BKW AROUND 09-10Z.
MEANWHILE...WHILE THE MID LEVEL MOISTURE INCREASED FROM THE WEST
LAST NIGHT...THE LOWER LEVEL MOISTURE MADE ITS FASTEST INITIAL
CHARGE NORTH...ON THE EASTERN SLOPES OF THE APPALACHIANS. YET...THE
925 TO 850 MB FLOW REMAINS WEAK AND STARTS VEERING MORE TOWARD SOUTH
AND SOUTHWEST. SO TOUGH CLOUD FORECAST TODAY FOR AREAS FROM BKW EAST
INTO THE UPPER GREENBRIER VALLEY.
MEANWHILE...IN THE WAKE OF THE MID LEVEL DISTURBANCE...BREAKS IN THE
CLOUDS COULD YIELD SOME BRIEF FOG IN THE MID OHIO VALLEY FOR DAWN.
NO MAJOR CHANGES TODAY...KEPT A 20/30 POPS OVER THE MOUNTAINS FOR
THE AFTERNOON HEATING IN THE WEAK FLOW. ALSO KEPT THE POSSIBILITY
OF CONVECTION FORMING FOR OUR NE KENTUCKY AND THE TRI STATE AROUND
HTS AFTER 18Z.
MOST MODELS LIKE THE ECMWF...GFS HOLD US DRY OVERNIGHT. BUT NAM
SHOWS MINOR FEATURES WITH INCREASING LOW LEVEL WINDS/FORCING AT
925 MB TO 850 MBS. IT IS TOO PREMATURE TO REMOVE POPS IN OUR
SOUTHERN AND WESTERN COUNTIES FOR TONIGHT. I DID TRY TO HOLD THE
ROUTE 50 CORRIDOR INCLUDING PKB TO CKB DRY MOST OF THE NIGHT. HAVE
POPS INCREASING INTO THE 30 TO 40 PERCENT RANGE ACROSS THE SOUTH
OVERNIGHT. CERTAINLY THE LONGER WE CAN HOLD OFF AREAS OF HEAVIER
CONVECTION THE BETTER...CONSIDERING THE ACTIVE PATTERN INTO THIS
WEEKEND.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
NEW 00Z MODELS LEAVE SOME QUESTION TO HOW THINGS WILL PLAY OUT
THROUGH THE SHORT TERM...AS ECMWF HAS MOVED BEST UPPER LEVEL SUPPORT
FARTHER NORTH WHILE NAM/GFS HAVE BEEN FAIRLY CONSISTENT WITH
PREVIOUS RUNS LOCATION WISE. ALL MODELS HAVE SLOWED DOWN A BIT WITH
THE PRECIP FOR WEDNESDAY...SO TRENDED THAT WAY. DESPITE THE MODEL
DIFFERENCES...THUNDERSTORMS LIKELY WEDNESDAY INTO WEDNESDAY NIGHT
AND WITH PW VALUES CLIMBING ABOVE 2 INCHES HEAVY RAIN IS ALSO
LIKELY. TRAIN OF VORT MAXES CONTINUES AS COLD FRONT APPROACHES
THURSDAY THROUGH FRIDAY. GFS STILL SHOWS THE COLD FRONT TRYING TO
PUSH THROUGH FRIDAY NIGHT...HOWEVER NEW ECMWF STALLS THE SURFACE
FRONT NEAR TO JUST NORTH OF CWA. THINK THE ECMWF MAY BE ON TO
SOMETHING...BUT WITH THIS BEING THE FIRST INDICATION...WON/T JUMP
FULLY ON IT YET. DID INCREASE LOWS FRIDAY NIGHT QUITE A BIT...WITH
ONLY MINIMAL CHANGES MADE TO OTHER TEMPS.
WILL CONTINUE WATER CONCERN MENTION IN HWO. THINK MOST LOCATIONS
SHOULD BE ABLE TO HANDLE WEDNESDAYS BATCH OF HEAVY RAIN SINCE WE
HAVE HAD SOME TIME TO DRY OUT SINCE LAST SIGNIFICANT RAIN...SO AM
MORE CONCERNED WITH REPETITIVE STORMS ADDING UP THROUGH THE END OF
THE WEEK. WITH THAT SAID...CAN NOT RULE OUT LOCALIZED ISSUES
WEDNESDAY DUE TO DOWNPOURS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
USED WPC THINKING FOR THIS PORTION OF THE FORECAST...WITH SOME MINOR
TWEAKS. A COLD FRONT SHOULD BE LOCATED JUST TO OUR SOUTHEAST
SATURDAY. A REINFORCING COLD FRONT SHOULD THEN PUSH SOUTHEAST
SATURDAY/SATURDAY NIGHT...BEFORE WEAK HIGH PRESSURE TAKES CONTROL BY
MONDAY.
BELOW NORMAL TEMPERATURES SHOULD PREVAIL THROUGH THE PERIOD.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
THE MID LEVEL DISTURBANCE CROSSING THE WV MOUNTAINS BETWEEN EKN AND
BKW AT 10Z. WITH BREAKS IN THE CLOUDS IN ITS WAKE...AREAS OF
IFR/LIFR IN FOG FORMING LATE...IN WAKE OF THE RAIN SHOWERS...FROM
EASTERN OHIO ACROSS NORTHERN WEST VIRGINIA INCLUDING PKB TO
CKB...AND EVEN TOWARD W22 AND EKN...FOR A BRIEF TIME AROUND 10Z TO
12Z. MAINLY MVFR IN FOG FURTHER SOUTH TOWARD CRW AND THE SOUTHERN
WV COAL FIELDS.
THE UPSLOPE FLOW ALONG THE EASTERN SLOPES OF THE APPALACHIANS
IS WEAK AND BECOMES MORE SOUTHERLY BY MIDDAY TODAY. THIS LOWERS MY
CONFIDENCE IN THE CEILINGS ALONG THE SPINE OF THE APPALACHIANS ON
EAST INTO THE GREENBRIER VALLEY. BECKLEY IN THE SOUTHERN MOUNTAINS
MAY BE ON THE WESTERN FRINGE OF THIS MAXIMUM IN LOW LEVEL MOISTURE
THIS MORNING...SO HAVE A SCATTERED TO BROKEN DECK THERE AROUND 2
THSD FT AGL.
IN DAYTIME HEATING HAVE SCATTERED TO BROKEN CLOUDS MOSTLY 2 TO 4
THSD FT AGL EXCEPT 4 TO 6 THSD FT ACROSS NORTHERN WV LOWLANDS.
A FEW SHOWERS OR THUNDERSTORMS COULD FORM IN THE AFTERNOON HEATING
OVER THE MOUNTAINOUS COUNTIES. INSTABILITY INCREASES IN THE TRI
STATE VCNTY OF HTS BY 21Z INCLUDING EASTERN KENTUCKY...SO SOME
THUNDERSTORMS COULD DEVELOP THERE LATE TODAY AND LINGER TONIGHT.
WITH MOISTURE INCREASING AT 850 MB AND BELOW WEST OF THE MOUNTAINS
TONIGHT...HAVE MORE WIDESPREAD CEILINGS A 3 TO 4 THSD FT DEVELOPING
00Z TO 06Z WEDNESDAY IN THE WESTERN LOWLANDS. VSBY COULD BE 5 TO 6
MILES IN HAZE WITH INCREASING SURFACE DEW POINTS. INSTABILITY
LINGERS OVERNIGHT...SO HAVE CHANCE POPS FOR CONVECTION CREEPING NE
INTO CENTRAL WV AND CRW VCNTY. EXPECTING DRY CONDITIONS TO HOLD
PKB TO CKB VCNTY OVERNIGHT THRU 12Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: EARLY MORNING FOG IN WAKE OF THE RAIN COULD
LINGER AN HOUR LONGER. COVERAGE AND TIMING OF ANY OVERNIGHT CONVECTION
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 08/06/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY H M M H M H H H H H H H
HTS CONSISTENCY H M M M M H H H H H H H
BKW CONSISTENCY M M M M M M M M M H H H
EKN CONSISTENCY H M M H H M H H H H H H
PKB CONSISTENCY L L L L H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z WEDNESDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION WEDNESDAY INTO SATURDAY. IN HUMID
AIR IFR CEILINGS COULD EVEN DEVELOP OUTSIDE THE CONVECTION...
ESPECIALLY AT NIGHT AND INTO THE MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
430 AM EDT TUE AUG 6 2013
.SYNOPSIS...
WEAK DISTURBANCE EXITS THE MOUNTAIN COUNTIES THIS MORNING. INSTABILITY
INCREASES LATE TODAY AND OVERNIGHT. STRONGER MID LEVEL DISTURBANCE
PASSES WEDNESDAY. MORE ROUNDS OF CONVECTION INTO THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
ONCE YOU GET SPOILED BY THOSE RARE LOWER DEW POINTS IN THE DOG DAYS
OF SUMMER...YOU HATE TO SEE THEM LEAVE. THE INITIAL MID LEVEL
DISTURBANCE WAS CROSSING THE CENTRAL WV MOUNTAINS THIS EARLY HOUR OF
08Z. A SECONDARY 500 MB VORT IS INDICATED ON THE 07Z RAP MODEL
PASSING N OF BKW AROUND 09-10Z.
MEANWHILE...WHILE THE MID LEVEL MOISTURE INCREASED FROM THE WEST
LAST NIGHT...THE LOWER LEVEL MOISTURE MADE ITS FASTEST INITIAL
CHARGE NORTH...ON THE EASTERN SLOPES OF THE APPALACHIANS. YET...THE
925 TO 850 MB FLOW REMAINS WEAK AND STARTS VEERING MORE TOWARD SOUTH
AND SOUTHWEST. SO TOUGH CLOUD FORECAST TODAY FOR AREAS FROM BKW EAST
INTO THE UPPER GREENBRIER VALLEY.
MEANWHILE...IN THE WAKE OF THE MID LEVEL DISTURBANCE...BREAKS IN THE
CLOUDS COULD YIELD SOME BRIEF FOG IN THE MID OHIO VALLEY FOR DAWN.
NO MAJOR CHANGES TODAY...KEPT A 20/30 POPS OVER THE MOUNTAINS FOR
THE AFTERNOON HEATING IN THE WEAK FLOW. ALSO KEPT THE POSSIBILITY
OF CONVECTION FORMING FOR OUR NE KENTUCKY AND THE TRI STATE AROUND
HTS AFTER 18Z.
MOST MODELS LIKE THE ECMWF...GFS HOLD US DRY OVERNIGHT. BUT NAM
SHOWS MINOR FEATURES WITH INCREASING LOW LEVEL WINDS/FORCING AT
925 MB TO 850 MBS. IT IS TOO PREMATURE TO REMOVE POPS IN OUR
SOUTHERN AND WESTERN COUNTIES FOR TONIGHT. I DID TRY TO HOLD THE
ROUTE 50 CORRIDOR INCLUDING PKB TO CKB DRY MOST OF THE NIGHT. HAVE
POPS INCREASING INTO THE 30 TO 40 PERCENT RANGE ACROSS THE SOUTH
OVERNIGHT. CERTAINLY THE LONGER WE CAN HOLD OFF AREAS OF HEAVIER
CONVECTION THE BETTER...CONSIDERING THE ACTIVE PATTERN INTO THIS
WEEKEND.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
NEW 00Z MODELS LEAVE SOME QUESTION TO HOW THINGS WILL PLAY OUT
THROUGH THE SHORT TERM...AS ECMWF HAS MOVED BEST UPPER LEVEL SUPPORT
FARTHER NORTH WHILE NAM/GFS HAVE BEEN FAIRLY CONSISTENT WITH
PREVIOUS RUNS LOCATION WISE. ALL MODELS HAVE SLOWED DOWN A BIT WITH
THE PRECIP FOR WEDNESDAY...SO TRENDED THAT WAY. DESPITE THE MODEL
DIFFERENCES...THUNDERSTORMS LIKELY WEDNESDAY INTO WEDNESDAY NIGHT
AND WITH PW VALUES CLIMBING ABOVE 2 INCHES HEAVY RAIN IS ALSO
LIKELY. TRAIN OF VORT MAXES CONTINUES AS COLD FRONT APPROACHES
THURSDAY THROUGH FRIDAY. GFS STILL SHOWS THE COLD FRONT TRYING TO
PUSH THROUGH FRIDAY NIGHT...HOWEVER NEW ECMWF STALLS THE SURFACE
FRONT NEAR TO JUST NORTH OF CWA. THINK THE ECMWF MAY BE ON TO
SOMETHING...BUT WITH THIS BEING THE FIRST INDICATION...WON/T JUMP
FULLY ON IT YET. DID INCREASE LOWS FRIDAY NIGHT QUITE A BIT...WITH
ONLY MINIMAL CHANGES MADE TO OTHER TEMPS.
WILL CONTINUE WATER CONCERN MENTION IN HWO. THINK MOST LOCATIONS
SHOULD BE ABLE TO HANDLE WEDNESDAYS BATCH OF HEAVY RAIN SINCE WE
HAVE HAD SOME TIME TO DRY OUT SINCE LAST SIGNIFICANT RAIN...SO AM
MORE CONCERNED WITH REPETITIVE STORMS ADDING UP THROUGH THE END OF
THE WEEK. WITH THAT SAID...CAN NOT RULE OUT LOCALIZED ISSUES
WEDNESDAY DUE TO DOWNPOURS.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
USED WPC THINKING FOR THIS PORTION OF THE FORECAST...WITH SOME MINOR
TWEAKS. A COLD FRONT SHOULD BE LOCATED JUST TO OUR SOUTHEAST
SATURDAY. A REINFORCING COLD FRONT SHOULD THEN PUSH SOUTHEAST
SATURDAY/SATURDAY NIGHT...BEFORE WEAK HIGH PRESSURE TAKES CONTROL BY
MONDAY.
BELOW NORMAL TEMPERATURES SHOULD PREVAIL THROUGH THE PERIOD.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THE OLD SQUEEZE PLAY...WITH THE LAST OF THE DRIER AIR EXITING.
MID LEVEL DISTURBANCES IN THE WNW FLOW AT 700 MB CROSSING 06Z TO 12Z
WILL CAUSE SOME SPOTTY LIGHT RAIN SHOWERS MAINLY CKB TO EKN VCNTY.
MEANWHILE...FLOW AROUND 925 MB FROM THE EAST AND SOUTHEAST...WITH
LOW LEVEL MOISTURE INCREASING NORTH...UP THE EASTERN SLOPES OF THE
APPALACHIANS. THAT FLOW IN VERY WEAK AND BECOMES MORE SOUTHERLY BY
MIDDAY TODAY. THIS LOWERS MY CONFIDENCE IN THE CEILINGS ALONG THE
SPINE OF THE APPALACHIANS ON EAST INTO THE GREENBRIER VALLEY.
BECKLEY IN THE SOUTHERN MOUNTAINS MAY BE ON THE WESTERN FRINGE OF
THIS MAXIMUM IN LOW LEVEL MOISTURE THIS MORNING...SO HAVE A
SCATTERED TO BROKEN DECK THERE AROUND 2 THSD FT AGL.
THERE MAY BE SOME BREAKS IN THE MID CLOUDS OVER THE WESTERN LOWLANDS
DURING THE PREDAWN...SO COULD STILL SEE SOME BRIEF 1 TO 3 MILES IN
FOG TOWARD DAWN.
A FEW SHOWERS OR THUNDERSTORMS COULD FORM IN THE AFTERNOON HEATING
OVER THE MOUNTAINOUS COUNTIES. INSTABILITY INCREASES IN THE TRI
STATE VCNTY OF HTS BY 21Z INCLUDING EASTERN KENTUCKY...SO SOME
THUNDERSTORMS COULD DEVELOP THERE LATE TODAY AND LINGER INTO THIS
EVENING.
WITH MOISTURE INCREASING AT 850 MB AND BELOW WEST OF THE MOUNTAINS
TONIGHT...HAVE MORE WIDESPREAD CEILINGS A 3 TO 4 THSD FT DEVELOPING
00Z TO 06Z WEDNESDAY IN THE WESTERN LOWLANDS. VSBY COULD BE 5 TO 6
MILES IN HAZE WITH INCREASING SURFACE DEW POINTS. INSTABILITY
LINGERS OVERNIGHT...SO HAVE CHANCE POPS FOR CONVECTION CREEPING NE
CENTRAL WV AND CRW VCNTY. SHOULD REMAIN DRY PKB TO CKB VCNTY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: IF MORE BREAKS DEVELOP SOONER...THICKER FOG
COULD DEVELOP THAN FORECAST DURING THE 09Z TO 12Z TIME FRAME IN THE
WESTERN LOWLANDS INCLUDING THE MID OHIO VALLEY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE TUE 08/06/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15
CRW CONSISTENCY H M M H M H H H H H H H
HTS CONSISTENCY H M M M M H H H H H H H
BKW CONSISTENCY M M M M M M M M M H H H
EKN CONSISTENCY H M M H H M H H H H H H
PKB CONSISTENCY L L L L H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z WEDNESDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION WEDNESDAY INTO SATURDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...JSH
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
214 AM EDT TUE AUG 6 2013
.SYNOPSIS...
WEAK DISTURBANCES WILL MOVE ACROSS THE AREA TONIGHT AND TUESDAY. A
MORE PRONOUNCED SYSTEM WILL MOVE ACROSS THE AREA LATE TUESDAY
NIGHT INTO WEDNESDAY. A COLD FRONT WILL MOVE THROUGH THE REGION
WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ABUNDANT MOISTURE ALOFT IN NORTHWESTERLY FLOW IS HELPING TO BRING
PATCHES OF SPRINKLES AND LIGHT RAIN ACROSS CENTRAL INDIANA AND
CENTRAL OHIO THIS EVENING. THE TREND OVER THE PAST FEW HOURS HAS
BEEN TO WEAKEN THE AREAS OF PRECIPITATION. HAVE FORECAST THESE
SHOWERS TO GRADUALLY DISSIPATE AS THEY SHIFT EAST TO SOUTHEAST
THROUGH THE LATE EVENING. OF NOTEWORTHINESS...LATEST RUC IS TRYING
TO REDEVELOP SHOWERS ACROSS NORTHERN INDIANA EARLY IN THE MORNING
AND THESE SHOWERS COULD MAKE IT TO OUR NORTHWESTERN ZONES AROUND
SUNRISE. THIS MORNING ACTIVITY IS ALSO COARSELY DEPICTED IN THE
12Z ECMWF AND THEREFORE MAY NEED TO INTRODUCE POPS ACROSS THOSE
ZONES AFTER 11Z IF THESE ADDITIONAL SHOWERS BEGIN TO FILL IN
UPSTREAM OVER THE NEXT FEW HOURS. OTHERWISE...EXPECT MOSTLY CLOUDY
SKIES WITH TEMPERATURES FALLING INTO THE UPPER 60S ACROSS THE
WEST...TO THE UPPER 50S ACROSS OUR EASTERN ZONES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
A WEAK DISTURBANCE WILL BRING A CHANCE FOR SOME SHOWERS AND
THUNDERSTORMS ACROSS THE FA ON TUESDAY. A MORE WELL DEFINED SHORT
WAVE WILL APPROACH THE AREA TUESDAY NIGHT INTO WEDNESDAY. THIS
FEATURE WILL BRING WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY TO
THE AREA. MODELS HAVE BEEN INCONSISTENT WITH WHERE THE HEAVIEST
RAIN WILL BE WITH THIS FEATURE. THE BEST CHANCE FOR HEAVIER
RAINFALL WILL BE ACROSS SOUTHERN PORTIONS OF THE FA AND THEREFORE
ADDED FLOODING POTENTIAL IN TO THE HWO ACROSS THIS AREA. DECIDED
AGAINST A FLASH FLOOD WATCH DUE TO RELATIVELY HIGH FFG VALUES AND
MODEL INCONSISTENCIES WITH WHERE THE HEAVIEST RAINFALL WILL OCCUR.
ADDITIONAL PRECIPITATION WILL BE POSSIBLE ACROSS THE FA WEDNESDAY
NIGHT AS A COLD FRONT MOVES THROUGH.
SOUTHERLY FLOW ACROSS THE FA ON TUESDAY WILL ALLOW FOR
TEMPERATURES TO RISE INTO THE 80S. TEMPERATURES ON WEDNESDAY WILL
BE COOLER WITH HIGHS IN THE UPPER 70S TO LOWER 80S DUE TO MORE
WIDESPREAD PRECIPITATION AND CLOUD COVER ACROSS THE FA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
MOST GUIDANCE HAS TRENDED TOWARDS A DRIER SOLUTION FOR THURSDAY. A
WEAK FRONTAL BOUNDARY WILL REMAIN ACROSS THE SOUTH BUT FORCING DOES
NOT LOOK PARTICULARLY STRONG AT THIS TIME. SO HAVE ONLY KEPT LOW
CHANCE POPS IN FOR THAT PERIOD.
CHANCE OF RAIN WILL INCREASE AGAIN LATE THURSDAY NIGHT AND
PARTICULARLY INTO FRIDAY AS A WAVE MOVES ALONG THE STALLED FRONT.
HAVE INCREASED POPS TO LIKELY ACROSS THE SOUTHERN COUNTIES. THIS
WILL PUSH OFF TO THE EAST DURING FRIDAY NIGHT. HIGH PRESSURE WILL
BUILD IN FOR THE WEEKEND. THERE IS THE POTENTIAL FOR A WEAK SYSTEM
TO SWING INTO THE REGION BY MONDAY. BUT SIGNAL IS NOT VERY STRONG
AND AT DAY 7 HAVE KEPT ANY CHANCE OF RAIN RATHER LOW.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
NORTHWEST FLOW WITH MID TO HIGH LEVEL CLOUDS MOVING ACROSS THE AREA
THROUGH THE EARLY MORNING HOURS. UPSTREAM OF THIS DECK...A LARGE AREA
OF VFR LOW CLOUDS AROUND 5000 FEET APPEARS WILL SPREAD ACROSS OUR
AREA. THE VFR LOW CLOUD DECK WILL LIKELY REMAIN ACROSS THE TAFS
THROUGH THE DAY...BECOMING SCATTERED AT TIMES. SHOWERS WILL BECOME
POSSIBLE LATE IN THE AFTERNOON WEST OF INTERSTATE 75...WITH THE
BEST CHANCE FOR A SHOWER BEING AT KDAY. SINCE LIKELIHOOD IS LOW HAVE
KEPT THE TAFS DRY THRU THE DAY. HAVE A MENTION OF VCSH AT 30 HOUR
KCVG TAF SITE TOWARD SUNRISE WEDNESDAY WITH PRECIP APPROACHING
FROM THE SW.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY INTO THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...LATTO
SHORT TERM...NOVAK
LONG TERM...
AVIATION...AR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
728 AM EDT TUE AUG 6 2013
.SYNOPSIS...
AN INCREASINGLY MOIST AND UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE FIRST PART OF THE WEEKEND...AS MULTIPLE FRONTS APPROACH
AND EVENTUALLY MOVE ACROSS THE REGION. A GRADUAL WARMING TREND TO
NEAR NORMAL TEMPERATURES IS EXPECTED THROUGH THE END OF THE
WEEK...BEFORE ANOTHER SHOT OF SEASONABLY COOL AIR ARRIVES ON
SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
IR SATL TRENDS SINCE MIDNIGHT HAVE DEPICTED A NOTABLE INCREASE IN
LOW-MID LEVEL CLOUDS ACRS A GOOD PORTION OF THE CWA. THE IR SATL
IMAGERY ALSO SHOWS FOG IN THE NRN RIVER/STREAM VALLEYS...WHERE
AIR/WATER TEMP SPREADS ARE AGAIN RUNNING 25-30 DEGREES. VWP/S FROM
IAD/BWI INDICATE THE 925-850MB FLOW HAS VEERED TO THE S-SW...AND
LATEST RUC MESO ANALYSIS SHOW A MSTR AXIS /+13-15C 850MB DEWPTS/
EXTENDING NWD ALONG THE ERN SLOPES OF THE APPLCHNS ON THE WRN
PERIPHERY OF DEPARTING SFC HIGH. THIS ENHANCED MSTR FLUX APPEARS
TO BE OVERRUNNING A WARM FRONT OVER NRN VA WITH DEVELOPING SHOWERS
STARTING TO PEEL NWD FROM THE MAIN W-E RAIN BAND TWD SRN MD.
THEREFORE CANT RULE OUT AN ISOLD SHOWER OVER THE FAR S-CNTRL OR
SERN ZONES PRIOR TO 12Z.
WEAK BUT PERSISTENT LLVL WARM AIR/MSTR ADVECTION AND BROAD ISENT
LIFT OVERRUNNING THE WARM FRONT OVER NRN VA WILL LKLY SUPPORT THE
DEVELOPMENT OF SCT SHOWERS...SPREADING FROM SOUTH TO NORTH DURING
THE MID-LATE MORNING THRU THE AFTN HOURS. SHORTWAVES EMBEDDED
WITHIN THE SEASONABLY STRONG WNW FLOW ALOFT ON THE SRN PERIPHERY
OF CLOSED/SLOW-MOVING UPPER LOW CENTERED OVER NRN MANITOBA/ONTARIO
WILL PROVIDE ENOUGH LARGE SCALE LIFT TO AID IN SHOWER DEVELOPMENT.
A FEW ISOLD THUNDERSTORMS WITH LOCALIZED HEAVY DOWNPOURS MAY ALSO
DEVELOP IN THE AFTN...BUT FOR THE MOST PART INSTABILITY WILL BE
WEAK WITH MEAN CAPES GENERALLY AOB 500 J/KG. MODEL QPFS ARE IN
REASONABLY GOOD AGREEMENT IN KEEPING THE BETTER RAINFALL AXIS TO
THE SOUTH OF THE MASON-DIXON LINE FROM SRN VA NEWD INTO DE...WITH
JUST LGT AMTS /0.1-0.25 INCHES/ OVER CNTRL AND SERN PA. THE
STEADILY INCREASING MSTR AND CLOUDS WILL KEEP MAX TEMPS IN THE
LOW TO MID 70S...AVERAGING A FEW TO SEVERAL DEGREES BELOW NORMAL
DEPENDING ON LOCATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE AFOREMENTIONED WARM FRONT WILL LIFT NWD INTO CNTRL PA TONIGHT
WITH BROAD LLVL SWLY FLOW CONTINUING TO ADVECT HIGHER PWS/60+
DEWPOINTS INTO THE AREA. MDL CONSENSUS STILL FAVORS THE ERN 1/2 TO
1/3 OF THE CWA WITH THE BEST CHC FOR LGT SHOWERS OVERNIGHT INTO
EARLY WEDNESDAY MORNING. IN CONTRAST TO DAYTIME HIGHS...THICKENING
CLOUDS PLUS INCREASING MSTR/DEWPOINTS WILL RESULT IN WARMER THAN
AVG MIN TEMPS WITH READINGS IN THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A ZONAL FLOW ACROSS THE NORTHERN CONUS WILL PREVAIL ACROSS THE
REGION FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NUMEROUS
EMBEDDED DISTURBANCES WILL ACT ON MONSOONAL MOISTURE FROM THE
SOUTHWESTERN UNITED STATES AND NEARLY STATIONARY BOUNDARY LAYER
FORCING TO PRODUCE A LOCALLY HEAVY RAIN/FLASH FLOOD THREAT ON THU-
FRI BEFORE DRIER AND COOLER CONDS RETURN BY LATE SAT AND SUN.
CLOUDS/PCPN SHOULD OFFSET WARMING ALOFT AND KEEP TEMPS NEAR TO
SLIGHTLY BELOW AVG. MDL DATA INDICATES THE COLD FRONT WILL BECOME
MUCH LESS PROGRESSIVE OR STALL OUT OVER THE UPPER OH VLY WED NGT
INTO THUR.
MODELS AND ENS MEANS CENTER AROUND THE GENERAL IDEA OF A
MODERATELY SLOW PROGRESSION OF THE CLOSED LOW TRACKING EWD BTWN
THE GRT LKS AND HUDSON BAY FROM THU THRU SAT. AT THE SFC...THE
COLD FRONT TURN Q-STNRY BNDRY IN THE OH VLY...WHICH WAS ASSOCIATED
WITH THE LEAD SHORTWAVE TROUGH...SHOULD PUSH SLOWLY EWD ACRS CNTRL
PA ON DAY4/THU. THE SFC PATTERN GETS QUITE COMPLICATED FRI-SAT AS
WPC PROGS SHOW THE FIRST BOUNDARY STALLING OUT OVER THE SRN MID-
ATLC STATES AND SECONDARY COLD FRONT APPROACHING FROM THE GREAT
LAKES. WAVES OF LOW PRESSURE RIDING NEWD ALONG THESE ENCROACHING
FRONTS COULD KEEP UNSETTLED CONDS IN THE FCST THRU THE FIRST PART
OF THE WEEKEND.
ANOTHER PUSH OF WESTERLIES SHOULD OVERSPREAD THE AREA BY SUNDAY
AND NUDGE THE SECOND FRONT EWD TO OR OFF THE COAST. A LARGE AREA OF
CANADIAN HIGH PRESSURE SHOULD SUPPLY ANOTHER REFRESHINGLY COOL/DRY
AIRMASS INTO THE GREAT LAKES AND NORTHEAST BY NEXT SUNDAY. DON`T
EXPECT TEMPS TO FLUCTUATE VERY MUCH THRU THE MEDIUM
RANGE...CONTINUING TO AVG NEAR TO SLIGHTLY BELOW NORMAL FOR EARLY
AUGUST.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
S-SWLY RETURN FLOW ON THE WRN PERIPHERY OF DEPARTING HIGH PRES
SLIDING OFF THE EAST COAST WILL BRING INCREASING MSTR AND
THICKENING LOW-MID CLOUDS INTO CNTRL PA THRU TONIGHT. THE
INCREASINGLY MOIST LLVL FLOW WILL OVERRUN A WARM FRONT LIFTING
SLOWLY NWD FROM VA AND SUPPORT SCT SHOWERS /WITH ISOLD TSRA AND
LOCALLY HVY DOWNPOURS/ INTO THE AFTN. THE S-CNTRL AND SERN
AIRFIELDS STAND THE GREATEST CHC TO BE IMPACTED BY THE SHOWER
ACTIVITY...AND ADDED VCSH TO MDT/LNS BASED ON THE LATEST COSPA
DATA. EXPECT CIG/VIS RESTRICTIONS TO BECOME WIDESPREAD TONIGHT
INTO EARLY WEDNESDAY AS SLY FLOW AND LLVL MSTR CONTINUES TO
INCREASE AHEAD OF THE AFOREMENTIONED WARM FRONT.
OUTLOOK...
WED-FRI...MVFR/VFR. TWO FRONTAL SYSTEMS WILL BRING PERIODS OF
SHOWERS AND OCNL TSTMS.
SAT...BCMG VFR AS HIGH PRES BUILDS SEWD FROM THE UPPER MIDWEST.
&&
.EQUIPMENT...
KCCX HAS SUFFERED MULTIPLE PEDESTAL DYNAMIC FAULTS EARLY THIS
MORNING...CAUSING IT TO GO INTO STAND-BY MODE. THE RADAR WILL
REMAIN IN STAND-BY MODE UNTIL OUR TECHNICIANS CAN DIAGNOSE THE
PROBLEM LATER THIS MORNING. WE APOLOGIZE FOR THE INCONVENIENCE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DEVOIR/GARTNER
AVIATION...STEINBUGL
EQUIPMENT...STEINBUGL/DEVOIR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
448 AM EDT TUE AUG 6 2013
.SYNOPSIS...
AN INCREASINGLY MOIST AND UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE FIRST PART OF THE WEEKEND...AS MULTIPLE FRONTS APPROACH
AND EVENTUALLY MOVE ACROSS THE REGION. A GRADUAL WARMING TREND TO
NEAR NORMAL TEMPERATURES IS EXPECTED THROUGH THE END OF THE
WEEK...BEFORE ANOTHER SHOT OF SEASONABLY COOL AIR ARRIVES ON
SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
IR SATL TRENDS SINCE MIDNIGHT HAVE DEPICTED A NOTABLE INCREASE IN
LOW-MID LEVEL CLOUDS ACRS A GOOD PORTION OF THE CWA. THE IR SATL
IMAGERY ALSO SHOWS FOG IN THE NRN RIVER/STREAM VALLEYS...WHERE
AIR/WATER TEMP SPREADS ARE AGAIN RUNNING 25-30 DEGREES. VWP/S FROM
IAD/BWI INDICATE THE 925-850MB FLOW HAS VEERED TO THE S-SW...AND
LATEST RUC MESO ANALYSIS SHOW A MSTR AXIS /+13-15C 850MB DEWPTS/
EXTENDING NWD ALONG THE ERN SLOPES OF THE APPLCHNS ON THE WRN
PERIPHERY OF DEPARTING SFC HIGH. THIS ENHANCED MSTR FLUX APPEARS
TO BE OVERRUNNING A WARM FRONT OVER NRN VA WITH DEVELOPING SHOWERS
STARTING TO PEEL NWD FROM THE MAIN W-E RAIN BAND TWD SRN MD.
THEREFORE CANT RULE OUT AN ISOLD SHOWER OVER THE FAR S-CNTRL OR
SERN ZONES PRIOR TO 12Z.
WEAK BUT PERSISTENT LLVL WARM AIR/MSTR ADVECTION AND BROAD ISENT
LIFT OVERRUNNING THE WARM FRONT OVER NRN VA WILL LKLY SUPPORT THE
DEVELOPMENT OF SCT SHOWERS...SPREADING FROM SOUTH TO NORTH DURING
THE MID-LATE MORNING THRU THE AFTN HOURS. SHORTWAVES EMBEDDED
WITHIN THE SEASONABLY STRONG WNW FLOW ALOFT ON THE SRN PERIPHERY
OF CLOSED/SLOW-MOVING UPPER LOW CENTERED OVER NRN MANITOBA/ONTARIO
WILL PROVIDE ENOUGH LARGE SCALE LIFT TO AID IN SHOWER DEVELOPMENT.
A FEW ISOLD THUNDERSTORMS WITH LOCALIZED HEAVY DOWNPOURS MAY ALSO
DEVELOP IN THE AFTN...BUT FOR THE MOST PART INSTABILITY WILL BE
WEAK WITH MEAN CAPES GENERALLY AOB 500 J/KG. MODEL QPFS ARE IN
REASONABLY GOOD AGREEMENT IN KEEPING THE BETTER RAINFALL AXIS TO
THE SOUTH OF THE MASON-DIXON LINE FROM SRN VA NEWD INTO DE...WITH
JUST LGT AMTS /0.1-0.25 INCHES/ OVER CNTRL AND SERN PA. THE
STEADILY INCREASING MSTR AND CLOUDS WILL KEEP MAX TEMPS IN THE
LOW TO MID 70S...AVERAGING A FEW TO SEVERAL DEGREES BELOW NORMAL
DEPENDING ON LOCATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
THE AFOREMENTIONED WARM FRONT WILL LIFT NWD INTO CNTRL PA TONIGHT
WITH BROAD LLVL SWLY FLOW CONTINUING TO ADVECT HIGHER PWS/60+
DEWPOINTS INTO THE AREA. MDL CONSENSUS STILL FAVORS THE ERN 1/2 TO
1/3 OF THE CWA WITH THE BEST CHC FOR LGT SHOWERS OVERNIGHT INTO
EARLY WEDNESDAY MORNING. IN CONTRAST TO DAYTIME HIGHS...THICKENING
CLOUDS PLUS INCREASING MSTR/DEWPOINTS WILL RESULT IN WARMER THAN
AVG MIN TEMPS WITH READINGS IN THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A ZONAL FLOW ACROSS THE NORTHERN CONUS WILL PREVAIL ACROSS THE
REGION FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NUMEROUS
EMBEDDED DISTURBANCES WILL ACT ON MONSOONAL MOISTURE FROM THE
SOUTHWESTERN UNITED STATES AND NEARLY STATIONARY BOUNDARY LAYER
FORCING TO PRODUCE A LOCALLY HEAVY RAIN/FLASH FLOOD THREAT ON THU-
FRI BEFORE DRIER AND COOLER CONDS RETURN BY LATE SAT AND SUN.
CLOUDS/PCPN SHOULD OFFSET WARMING ALOFT AND KEEP TEMPS NEAR TO
SLIGHTLY BELOW AVG. MDL DATA INDICATES THE COLD FRONT WILL BECOME
MUCH LESS PROGRESSIVE OR STALL OUT OVER THE UPPER OH VLY WED NGT
INTO THUR.
MODELS AND ENS MEANS CENTER AROUND THE GENERAL IDEA OF A
MODERATELY SLOW PROGRESSION OF THE CLOSED LOW TRACKING EWD BTWN
THE GRT LKS AND HUDSON BAY FROM THU THRU SAT. AT THE SFC...THE
COLD FRONT TURN Q-STNRY BNDRY IN THE OH VLY...WHICH WAS ASSOCIATED
WITH THE LEAD SHORTWAVE TROUGH...SHOULD PUSH SLOWLY EWD ACRS CNTRL
PA ON DAY4/THU. THE SFC PATTERN GETS QUITE COMPLICATED FRI-SAT AS
WPC PROGS SHOW THE FIRST BOUNDARY STALLING OUT OVER THE SRN MID-
ATLC STATES AND SECONDARY COLD FRONT APPROACHING FROM THE GREAT
LAKES. WAVES OF LOW PRESSURE RIDING NEWD ALONG THESE ENCROACHING
FRONTS COULD KEEP UNSETTLED CONDS IN THE FCST THRU THE FIRST PART
OF THE WEEKEND.
ANOTHER PUSH OF WESTERLIES SHOULD OVERSPREAD THE AREA BY SUNDAY
AND NUDGE THE SECOND FRONT EWD TO OR OFF THE COAST. A LARGE AREA OF
CANADIAN HIGH PRESSURE SHOULD SUPPLY ANOTHER REFRESHINGLY COOL/DRY
AIRMASS INTO THE GREAT LAKES AND NORTHEAST BY NEXT SUNDAY. DON`T
EXPECT TEMPS TO FLUCTUATE VERY MUCH THRU THE MEDIUM
RANGE...CONTINUING TO AVG NEAR TO SLIGHTLY BELOW NORMAL FOR EARLY
AUGUST.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
SLY RETURN FLOW DEVELOPING ON THE WRN PERIPHERY OF HIGH PRES
SLIDING OFF THE EAST COAST WILL BRING INCREASING MSTR AND
THICKENING LOW-MID CLOUDS INTO CNTRL PA THRU TONIGHT. A LLVL MSTR
CONVERGENCE AXIS EXTENDING NWD FM THE SE STATES ALONG THE ERN
SLOPES OF THE APPLCHNS IS LKLY RESPONSIBLE FOR THE AREA OF 6-8KFT
CIGS OVER THE S-CNTRL AND SERN TAFS. EXPECT THESE CIGS TO THICKEN
AND LOWER 1-2KFT INTO THE MID MORNING AS BLYR COOLS AND LLVL FLOW
CONTINUES VEERING TO THE SOUTH-SOUTHEAST. THE INCREASINGLY MOIST
LLVL FLOW WILL OVERRUN A WARM FRONT LIFTING SLOWLY NEWD FROM THE
TN VLY AND CNTRL APPLCHNS AND SUPPORT SCT SHOWERS /WITH ISOLD
TSRA/ INTO THE AFTN. THE S-CNTRL AND SERN AIRFIELDS STAND THE
GREATEST CHC TO BE IMPACTED BY THE SHOWER ACTIVITY. EXPECT CIG
RESTRICTIONS TO BECOME MORE WIDESPREAD FROM TONIGHT INTO EARLY
WEDNESDAY AS SLY FLOW AND LLVL MSTR CONTINUES TO INCREASE AS WARM
FRONT LIFTS NEWD ACRS THE AIRSPACE.
OUTLOOK...
WED-FRI...MVFR/VFR. TWO FRONTAL SYSTEMS WILL BRING PERIODS OF
SHOWERS AND OCNL TSTMS.
SAT...BCMG VFR AS HIGH PRES BUILDS SEWD FROM THE UPPER MIDWEST.
&&
.EQUIPMENT...
KCCX HAS SUFFERED MULTIPLE PEDESTAL DYNAMIC FAULTS EARLY THIS
MORNING...CAUSING IT TO GO INTO STAND-BY MODE. THE RADAR WILL
REMAIN IN STAND-BY MODE UNTIL OUR TECHNICIANS CAN DIAGNOSE THE
PROBLEM LATER THIS MORNING. WE APOLOGIZE FOR THE INCONVENIENCE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DEVOIR/GARTNER
AVIATION...STEINBUGL
EQUIPMENT...STEINBUGL/DEVOIR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
433 AM EDT TUE AUG 6 2013
.SYNOPSIS...
AN INCREASINGLY MOIST AND UNSETTLED WEATHER PATTERN WILL PERSIST
INTO THE FIRST PART OF THE WEEKEND...AS MULTIPLE FRONTS APPROACH
AND EVENTUALLY MOVE ACROSS THE REGION. A GRADUAL WARMING TREND TO
NEAR NORMAL TEMPERATURES IS EXPECTED THROUGH THE END OF THE
WEEK...BEFORE ANOTHER SHOT OF SEASONABLY COOL AIR ARRIVES ON
SUNDAY.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
IR SATL TRENDS SINCE MIDNIGHT HAVE DEPICTED A NOTABLE INCREASE IN
LOW-MID LEVEL CLOUDS ACRS A GOOD PORTION OF THE CWA. THE IR SATL
IMAGERY ALSO SHOWS FOG IN THE NRN RIVER/STREAM VALLEYS...WHERE
AIR/WATER TEMP SPREADS ARE AGAIN RUNNING 25-30 DEGREES. VWP/S FROM
IAD/BWI INDICATE THE 925-850MB FLOW HAS VEERED TO THE S-SW...AND
LATEST RUC MESO ANALYSIS SHOW A MSTR AXIS /+13-15C 850MB DEWPTS/
EXTENDING NWD ALONG THE ERN SLOPES OF THE APPLCHNS ON THE WRN
PERIPHERY OF DEPARTING SFC HIGH. THIS ENHANCED MSTR FLUX APPEARS
TO BE OVERRUNNING A WARM FRONT OVER NRN VA WITH DEVELOPING SHOWERS
STARTING TO PEEL NWD FROM THE MAIN W-E RAIN BAND TWD SRN MD.
THEREFORE CANT RULE OUT AN ISOLD SHOWER OVER THE FAR S-CNTRL OR
SERN ZONES PRIOR TO 12Z.
WEAK BUT PERSISTENT LLVL WARM AIR/MSTR ADVECTION AND BROAD ISENT
LIFT OVERRUNNING THE WARM FRONT OVER NRN VA WILL LKLY SUPPORT THE
DEVELOPMENT OF SCT SHOWERS...SPREADING FROM SOUTH TO NORTH DURING
THE MID-LATE MORNING THRU THE AFTN HOURS. SHORTWAVES EMBEDDED
WITHIN THE SEASONABLY STRONG WNW FLOW ALOFT ON THE SRN PERIPHERY
OF CLOSED/SLOW-MOVING UPPER LOW CENTERED OVER NRN MANITOBA/ONTARIO
WILL PROVIDE ENOUGH LARGE SCALE LIFT TO AID IN SHOWER DEVELOPMENT.
A FEW ISOLD THUNDERSTORMS WITH LOCALIZED HEAVY DOWNPOURS MAY ALSO
DEVELOP IN THE AFTN...BUT FOR THE MOST PART INSTABILITY WILL BE
WEAK WITH MEAN CAPES GENERALLY AOB 500 J/KG. MODEL QPFS ARE IN
REASONABLY GOOD AGREEMENT IN KEEPING THE BETTER RAINFALL AXIS TO
THE SOUTH OF THE MASON-DIXON LINE FROM SRN VA NEWD INTO DE...WITH
JUST LGT AMTS /0.1-0.25 INCHES/ OVER CNTRL AND SERN PA. THE
STEADILY INCREASING MSTR AND CLOUDS WILL KEEP MAX TEMPS IN THE
LOW TO MID 70S...AVERAGING A FEW TO SEVERAL DEGREES BELOW NORMAL
DEPENDING ON LOCATION.
&&
.SHORT TERM /TONIGHT/...
THE AFOREMENTIONED WARM FRONT WILL LIFT NWD INTO CNTRL PA TONIGHT
WITH BROAD LLVL SWLY FLOW CONTINUING TO ADVECT HIGHER PWS/60+
DEWPOINTS INTO THE AREA. MDL CONSENSUS STILL FAVORS THE ERN 1/2 TO
1/3 OF THE CWA WITH THE BEST CHC FOR LGT SHOWERS OVERNIGHT INTO
EARLY WEDNESDAY MORNING. IN CONTRAST TO DAYTIME HIGHS...THICKENING
CLOUDS PLUS INCREASING MSTR/DEWPOINTS WILL RESULT IN WARMER THAN
AVG MIN TEMPS WITH READINGS IN THE LOW-MID 60S.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
A ZONAL FLOW ACROSS THE NORTHERN CONUS WILL PREVAIL ACROSS THE
REGION FROM WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. NUMEROUS
EMBEDDED DISTURBANCES WILL ACT ON MONSOONAL MOISTURE FROM THE
SOUTHWESTERN UNITED STATES AND NEARLY STATIONARY BOUNDARY LAYER
FORCING TO PRODUCE A LOCALLY HEAVY RAIN/FLASH FLOOD THREAT ON THU-
FRI BEFORE DRIER AND COOLER CONDS RETURN BY LATE SAT AND SUN.
CLOUDS/PCPN SHOULD OFFSET WARMING ALOFT AND KEEP TEMPS NEAR TO
SLIGHTLY BELOW AVG. MDL DATA INDICATES THE COLD FRONT WILL BECOME
MUCH LESS PROGRESSIVE OR STALL OUT OVER THE UPPER OH VLY WED NGT
INTO THUR.
MODELS AND ENS MEANS CENTER AROUND THE GENERAL IDEA OF A
MODERATELY SLOW PROGRESSION OF THE CLOSED LOW TRACKING EWD BTWN
THE GRT LKS AND HUDSON BAY FROM THU THRU SAT. AT THE SFC...THE
COLD FRONT TURN Q-STNRY BNDRY IN THE OH VLY...WHICH WAS ASSOCIATED
WITH THE LEAD SHORTWAVE TROUGH...SHOULD PUSH SLOWLY EWD ACRS CNTRL
PA ON DAY4/THU. THE SFC PATTERN GETS QUITE COMPLICATED FRI-SAT AS
WPC PROGS SHOW THE FIRST BOUNDARY STALLING OUT OVER THE SRN MID-
ATLC STATES AND SECONDARY COLD FRONT APPROACHING FROM THE GREAT
LAKES. WAVES OF LOW PRESSURE RIDING NEWD ALONG THESE ENCROACHING
FRONTS COULD KEEP UNSETTLED CONDS IN THE FCST THRU THE FIRST PART
OF THE WEEKEND.
ANOTHER PUSH OF WESTERLIES SHOULD OVERSPREAD THE AREA BY SUNDAY
AND NUDGE THE SECOND FRONT EWD TO OR OFF THE COAST. A LARGE AREA OF
CANADIAN HIGH PRESSURE SHOULD SUPPLY ANOTHER REFRESHINGLY COOL/DRY
AIRMASS INTO THE GREAT LAKES AND NORTHEAST BY NEXT SUNDAY. DON`T
EXPECT TEMPS TO FLUCTUATE VERY MUCH THRU THE MEDIUM
RANGE...CONTINUING TO AVG NEAR TO SLIGHTLY BELOW NORMAL FOR EARLY
AUGUST.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
SLY RETURN FLOW DEVELOPING ON THE WRN PERIPHERY OF HIGH PRES
SLIDING OFF THE EAST COAST WILL BRING INCREASING MSTR AND
THICKENING LOW-MID CLOUDS INTO CNTRL PA THRU TONIGHT. A LLVL MSTR
CONVERGENCE AXIS EXTENDING NWD FM THE SE STATES ALONG THE ERN
SLOPES OF THE APPLCHNS IS LKLY RESPONSIBLE FOR THE AREA OF 6-8KFT
CIGS OVER THE S-CNTRL AND SERN TAFS. EXPECT THESE CIGS TO THICKEN
AND LOWER 1-2KFT INTO THE MID MORNING AS BLYR COOLS AND LLVL FLOW
CONTINUES VEERING TO THE SOUTH-SOUTHEAST. THE INCREASINGLY MOIST
LLVL FLOW WILL OVERRUN A WARM FRONT LIFTING SLOWLY NEWD FROM THE
TN VLY AND CNTRL APPLCHNS AND SUPPORT SCT SHOWERS /WITH ISOLD
TSRA/ INTO THE AFTN. THE S-CNTRL AND SERN AIRFIELDS STAND THE
GREATEST CHC TO BE IMPACTED BY THE SHOWER ACTIVITY. EXPECT CIG
RESTRICTIONS TO BECOME MORE WIDESPREAD FROM TONIGHT INTO EARLY
WEDNESDAY AS SLY FLOW AND LLVL MSTR CONTINUES TO INCREASE AS WARM
FRONT LIFTS NEWD ACRS THE AIRSPACE.
OUTLOOK...
WED-FRI...MVFR/VFR. TWO FRONTAL SYSTEMS WILL BRING PERIODS OF
SHOWERS AND OCNL TSTMS.
SAT...BCMG VFR AS HIGH PRES BUILDS SEWD FROM THE UPPER MIDWEST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DEVOIR/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1238 PM CDT TUE AUG 6 2013
.UPDATE...
UPDATED AVIATION DISCUSSION BELOW FOR 18Z TAFS.
WEAK SURFACE LOW PRESSURE AREA IN SOUTHEAST ND MOVING EAST LATE
THIS MORNING WITH A WEAK COOL FRONT DROPPING IN BEHIND IT. MOST OF
THE CONVECTION WAS OVER THIS MORNING. THE HRRR MODEL WAS SHOWING
SOME REDEVELOPMENT OVER FAR NE SD/WC MN THIS AFTERNOON AND EVENING
AND ALSO ALONG THE WEAK COOL FRONT DROPPING IN FROM THE NORTH.
THUS...ADJUSTED POPS DOWNWARD ACROSS MOST OF THE REGION THROUGH
THE AFTERNOON.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH THURSDAY
PRECIPITATION CHANCES TODAY WILL BE THE MAIN FORECAST CHALLENGE.
THUNDERSTORMS CURRENTLY ONGOING ALONG AND SOUTH OF I-90 SHOULD
CONTINUE TO DRIFT ESE...CLIPPING ONLY THE SOUTHWEST PORTION OF THE
CWA THROUGH THE MID MORNING HOURS. ADDITIONAL CONVECTION IS MOVING
DUE EAST ALONG I-94 IN NORTH DAKOTA. THESE STORMS SHOULD REMAIN NORTH
OF THIS CWA THROUGH THE MORNING HOURS.
MODELS SORT OF AGREE WITH TWO POSSIBLE CLUSTERS OF STORMS
DEVELOPING LATER THIS AFTERNOON. ONE CLUSTER WOULD BE ACROSS
SOUTHEAST SOUTH DAKOTA WHERE BETTER INSTABILITY IS LOCATED ALONG
WITH A WEAK MID LEVEL SHORT WAVE. IF THIS ACTIVITY DEVELOPS...IT
SHOULD REMAIN SOUTH OF THIS CWA. THE SECONDARY CLUSTER WILL BE
ALONG A SLOWLY SOUTHWARD SINKING COLD FRONT. LESS INSTABILITY
ALONG THE FRONT...BUT SLIGHTLY BETTER 0-6 KM BULK SHEAR MAY RESULT
IN A FEW STRONGER STORMS IN NORTHEAST SOUTH DAKOTA AND WESTERN
MINNESOTA LATER THIS AFTERNOON.
A COOL CANADIAN HIGH PRESSURE SETTLING ACROSS THE REGION WILL
BRING DRY AND TRANQUIL CONDITIONS FOR WEDNESDAY AND FOR MOST OF
WEDNESDAY NIGHT. THEN ANOTHER SURFACE LOW PRESSURE SYSTEM WILL
MOVE ACROSS THE REGION DURING THE EARLY MORNING HOURS ON THURSDAY.
THERE SEEMS TO BE A GENERAL CONSENSUS WITH MOST OF THE CONVECTION
OCCURRING ACROSS SOUTHERN NORTH DAKOTA. THERE IS STILL A CHANCE
FOR THUNDERSTORMS ACROSS MOST OF THE CWA AS A TRAILING COLD FRONT
MOVES SOUTHWARD ACROSS THE CWA ON THURSDAY. SIGNIFICANTLY LESS
INSTABILITY SHOULD RESULT IN GENERAL THUNDERSTORMS.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY NIGHT
NO CHANGES FROM 24 HOURS AGO. NORTHWEST FLOW WILL STEER ONE OR
MORE MID-LEVEL SHORTWAVES THROUGH THE REGION ATOP A DECENT LOW TO
MID-LEVEL BAROCLINIC ZONE...RESULTING IN A COUPLE HALFWAY DECENT
CHANCES FOR MEASURABLE PRECIP OVER A GOODLY AMOUNT OF AREAL
COVERAGE OF THE CWA. SEEMS THE BEST CHANCES FOR PRECIPITATION...RIGHT
NOW...ARE ANCHORED ON FRIDAY NIGHT THROUGH SUNDAY MORNING. 925HPA
AND 850HPA THERMAL PROGS IN THE GFS AND ECMWF SUGGEST TEMPERATURES
WILL REMAIN GENERALLY NEAR TO BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD. AS OF 18Z A
BAND OF -SHRA STRETCHES FROM WESTERN THROUGH CENTRAL SD. HAVE
INCLUDED VCSH AT KPIR FOR THE AFTERNOON HOURS TO ACCOUNT FOR THIS.
OTHERWISE...AS A FRONTAL BOUNDARY MOVES ACROSS THE REGION
TODAY...A FEW SHRA/TSRA ARE POSSIBLE...MAINLY OVER EASTERN
PORTIONS OF THE AREA. HAVE INCLUDED A VCTS MENTION AT KATY LATER
THIS AFTERNOON. W/NW WINDS WILL BECOME MORE N/NE OVERNIGHT AS THE
MAIN PUSH OF COOLER AIR WORKS ITS WAY SOUTH OVER THE AREA. LIGHT
WINDS AND VFR CONDITIONS CAN BE EXPECTED ON WEDNESDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR/TMT
SHORT TERM...CONNELLY
LONG TERM...DORN
AVIATION...TMT
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1029 AM CDT TUE AUG 6 2013
.UPDATE...
WEAK SURFACE LOW PRESSURE AREA IN SOUTHEAST ND MOVING EAST LATE
THIS MORNING WITH A WEAK COOL FRONT DROPPING IN BEHIND IT. MOST OF
THE CONVECTION WAS OVER THIS MORNING. THE HRRR MODEL WAS SHOWING
SOME REDEVELOPMENT OVER FAR NE SD/WC MN THIS AFTERNOON AND EVENING
AND ALSO ALONG THE WEAK COOL FRONT DROPPING IN FROM THE NORTH.
THUS...ADJUSTED POPS DOWNWARD ACROSS MOST OF THE REGION THROUGH
THE AFTERNOON.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH THURSDAY
PRECIPITATION CHANCES TODAY WILL BE THE MAIN FORECAST CHALLENGE.
THUNDERSTORMS CURRENTLY ONGOING ALONG AND SOUTH OF I-90 SHOULD
CONTINUE TO DRIFT ESE...CLIPPING ONLY THE SOUTHWEST PORTION OF THE
CWA THROUGH THE MID MORNING HOURS. ADDITIONAL CONVECTION IS MOVING
DUE EAST ALONG I-94 IN NORTH DAKOTA. THESE STORMS SHOULD REMAIN NORTH
OF THIS CWA THROUGH THE MORNING HOURS.
MODELS SORT OF AGREE WITH TWO POSSIBLE CLUSTERS OF STORMS
DEVELOPING LATER THIS AFTERNOON. ONE CLUSTER WOULD BE ACROSS
SOUTHEAST SOUTH DAKOTA WHERE BETTER INSTABILITY IS LOCATED ALONG
WITH A WEAK MID LEVEL SHORT WAVE. IF THIS ACTIVITY DEVELOPS...IT
SHOULD REMAIN SOUTH OF THIS CWA. THE SECONDARY CLUSTER WILL BE
ALONG A SLOWLY SOUTHWARD SINKING COLD FRONT. LESS INSTABILITY
ALONG THE FRONT...BUT SLIGHTLY BETTER 0-6 KM BULK SHEAR MAY RESULT
IN A FEW STRONGER STORMS IN NORTHEAST SOUTH DAKOTA AND WESTERN
MINNESOTA LATER THIS AFTERNOON.
A COOL CANADIAN HIGH PRESSURE SETTLING ACROSS THE REGION WILL
BRING DRY AND TRANQUIL CONDITIONS FOR WEDNESDAY AND FOR MOST OF
WEDNESDAY NIGHT. THEN ANOTHER SURFACE LOW PRESSURE SYSTEM WILL
MOVE ACROSS THE REGION DURING THE EARLY MORNING HOURS ON THURSDAY.
THERE SEEMS TO BE A GENERAL CONSENSUS WITH MOST OF THE CONVECTION
OCCURRING ACROSS SOUTHERN NORTH DAKOTA. THERE IS STILL A CHANCE
FOR THUNDERSTORMS ACROSS MOST OF THE CWA AS A TRAILING COLD FRONT
MOVES SOUTHWARD ACROSS THE CWA ON THURSDAY. SIGNIFICANTLY LESS
INSTABILITY SHOULD RESULT IN GENERAL THUNDERSTORMS.
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY NIGHT
NO CHANGES FROM 24 HOURS AGO. NORTHWEST FLOW WILL STEER ONE OR
MORE MID-LEVEL SHORTWAVES THROUGH THE REGION ATOP A DECENT LOW TO
MID-LEVEL BAROCLINIC ZONE...RESULTING IN A COUPLE HALFWAY DECENT
CHANCES FOR MEASURABLE PRECIP OVER A GOODLY AMOUNT OF AREAL
COVERAGE OF THE CWA. SEEMS THE BEST CHANCES FOR PRECIPITATION...RIGHT
NOW...ARE ANCHORED ON FRIDAY NIGHT THROUGH SUNDAY MORNING. 925HPA
AND 850HPA THERMAL PROGS IN THE GFS AND ECMWF SUGGEST TEMPERATURES
WILL REMAIN GENERALLY NEAR TO BELOW NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
GOOD VFR AND DRY CONDITIONS ARE EXPECTED AT ALL FOUR TERMINALS
THROUGH THIS AFTERNOON. THEN...A COLD FRONT MOVING THROUGH THE
REGION COULD TOUCH OFF A FEW SHOWERS OR STORMS AT OR NEAR THE
KABR/KATY TERMINALS. THE COLD FRONT WILL ALSO BE SWITCHING WINDS
AROUND TO THE NORTHWEST.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...SD
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1024 PM CDT WED AUG 7 2013
.UPDATE...SCATTERED CONVECTION STILL GOING ON, MAINLY WEST OF
I-65. SO FAR, HRRR DOING A FAIRLY GOOD JOB HANDLING THE EVENING
ACTIVITY. MODEL DOES SHOW A SLIGHT INCREASE IN ACTIVITY OVERNIGHT,
BUT DON`T KNOW THAT IT JUSTIFIES LIKELY POP`S. WILL TREND BACK
TO SCATTERED FOR THE 06Z TO 12Z PERIOD AND UPDATE THE FORECAST
ACCORDINGLY.
&&
.PREV DISCUSSION... /ISSUED 631 PM CDT WED AUG 7 2013/
UPDATE...FOR 00Z AVIATION.
AVIATION...00Z TAF DISCUSSION.
MIXED BAG TONIGHT. ALL TERMINALS HAVE GONE VFR AT ISSUANCE AS THE
ATMOSPHERE SEEMS TO BE FAIRLY STABLE DUE TO EARLIER RAINS AND TS.
HIGH CLOUDS OVER THE EASTERN HALF OF MIDDLE TENNESSEE SHOULD
CONTINUE MOVING OUT OF THE AREA AND SET THE STAGE FOR SOME FOG AND
STRATUS DEVELOPMENT AROUND MIDNIGHT TONIGHT. WILL DROP CSV/CKV
THE LOWEST AND GO IFR BY 09Z-10Z AT BOTH. THE QUESTION STILL
REMAINS AS TO WHETHER WE WILL SEE ANY REDEVELOPMENT TONIGHT IN THE
WAY OF RAINS. SOME SHORT TERM GUIDANCE STILL SUGGESTS THIS...BUT
IS TRENDING AWAY FROM ANYTHING TOO WIDESPREAD. FOR THIS REASON...
WILL REMOVE ANY OVERNIGHT VC WORDING AND WORK FROM AMDS TONIGHT.
WILL NEED TO MONITOR UPSTREAM ACTIVITY AS WELL AS WE REMAIN IN A
QUASI-NW FLOW. LOOK FOR AFTERNOON TS DEVELOPMENT THURSDAY AROUND
ALL OF MIDDLE TENNESSEE.
UNGER
PREV DISCUSSION... /ISSUED 323 PM CDT WED AUG 7 2013/
DISCUSSION...STATUS QUO FOR THIS FORECAST CYCLE...WITH A MOIST
AND UNSETTLED PATTERN CONTINUING TO BRING GOOD CHANCES FOR SHOWERS
AND THUNDERSTORMS. PRECIPITABLE WATER VALUES WILL REMAIN WELL
ABOVE NORMAL THE NEXT COUPLE OF DAYS...A LITTLE OVER 2 INCHES. THIS
WILL MEAN THE POSSIBILITY FOR SOME LOCALLY HEAVY RAINFALL. THANKS
TO THE ON AND OFF NATURE OF THE RAIN...AND THE VARIABILITY IN
LOCATION...WE STILL DO NOT SEE THE NEED FOR A FLASH FLOOD WATCH AT
THIS TIME. AVERAGE QPF THROUGH FRIDAY LOOKS LIKE 1-2 INCHES...BUT
A FEW LOCATIONS IMPACTED BY STRONGER STORMS WILL CERTAINLY HAVE
GREATER AMOUNTS.
THE BIG QUESTION IS EXACTLY WHEN THE RAIN WILL OCCUR. SHORT RANGE
MODELS SEEM USELESS IN DETERMINING TRENDS INTO TONIGHT WITH
SOLUTIONS ALL OVER THE PLACE. RIGHT NOW IT APPEARS THAT EARLIER
STORMS HAVE "WORKED OVER" THE ATMOSPHERE...AND WE WILL HAVE AT
LEAST A FEW QUIET HOURS EARLY THIS EVENING. SOME REDEVELOPMENT IS
EXPECTED LATER...PERHAPS ANOTHER MCS SCENARIO WHERE STORMS DEVELOP
OVER MO AND COME IN FROM THE NORTHWEST LATE NIGHT. TIMING IS ALSO
HIGHLY UNCERTAIN THURSDAY AND FRIDAY WITH A SERIES OF WEAK WAVES
AND VARIOUS MESOSCALE BOUNDARIES TRAVERSING THE REGION. STILL...WE
WILL GO WITH HIGH POPS GIVEN GUIDANCE NUMBERS...RECENT
HISTORY...AND THE FAVORABLE STATE OF THE ATMOSPHERE.
THE MAIN CONCERN WITH STORMS THROUGH FRIDAY WILL BE HEAVY
RAINFALL. A FEW STRONG OR BRIEFLY SEVERE STORMS WITH GUSTY WINDS
CANNOT BE RULED OUT IN THE HEAT OF THE AFTERNOON THROUGH THE NEXT
COUPLE OF DAYS. INSTABILITY WILL BE GREATLY DEPENDENT ON AMOUNT
OF SURFACE HEATING.
MOS GUIDANCE CONTINUES TO OVERSHOOT ON THE HIGHS...SO CHOPPING OFF
A FEW DEGREES OVER THE NEXT COUPLE OF DAYS. HOWEVER...HIGH TEMPS
ARE HIGHLY DEPENDENT ON CLOUD COVER AND THUNDERSTORMS
COVERAGE...SO IF WE MANAGE TO SEE A LITTLE MORE SUN...TEMPERATURES
COULD JUMP QUICKLY TO 90+.
INTO THE WEEKEND...A FRONT WILL BE DROPPING ACROSS THE OHIO VALLEY
AND INTO TN. THIS BOUNDARY MAY SINK FAR ENOUGH FOR SLIGHTLY DRIER
TO COME IN BY LATE SUNDAY...BUT THAT SEEMS OPTIMISTIC. EVEN IF
THIS OCCURS...THE BOUNDARY WILL STILL BE CLOSE ENOUGH TO MAINTAIN
A CHANCE FOR SHOWERS AND STORMS.
INTO NEXT WEEK...NORTHWEST FLOW ALOFT MAY BRING A LITTLE MORE
COOLING AND DRYING...BUT NORTHWEST FLOW IS NOTORIOUSLY
UNSETTLED...SO A CHANCE FOR THUNDERSTORMS WILL REMAIN IN THE
FORECAST EVERY DAY.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
ROSE
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
740 PM CDT WED AUG 7 2013
.UPDATE...
DIFFICULT TO GET A HANDLE ON EXACTLY WHERE ANY SHOWERS AND
THUNDERSTORMS WILL DEVELOP THIS EVENING WITH MANY OF THE MODELS
BEING POOR IN HANDLING THE CURRENT SITUATION. A WEAK WARM EXTENDS
FROM NORTHEAST AR INTO SOUTHWEST TN AT EARLY EVENING. A FEW
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG THE TN RIVER IN
WEST TN JUST NORTH OF THIS FRONT. THE HIGH RESOLUTION RAPID
REFRESH MODEL SEEMS TO BE DOING THE BEST JOB...AND THIS MODEL
INDICATE FURTHER DEVELOPMENT THIS EVENING NORTH OF THE FRONT
ACROSS PORTIONS OF NORTHEAST AR...THE MO BOOTHEEL...AND PORTIONS
OF WEST TN. UPDATED TO REMOVE MENTION OF RAIN THIS EVENING SOUTH
OF THIS AREA. ALSO ADJUSTED THE SKY COVER A LITTLE FOR THIS
EVENING...OTHERWISE LITTLE CHANGE MADE TO THE EARLIER FORECAST.
JCL
&&
.PREV DISCUSSION... /ISSUED 312 PM CDT WED AUG 7 2013/
THE OUTFLOW BOUNDARY GENERATED FROM THIS MORNINGS MCS CONTINUES TO
PUSH ACROSS NORTHERN MISSISSIPPI. SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED ALONG AND IN ADVANCE OF THE BOUNDARY AND WILL
CONTINUE TO PUSH ACROSS THE REMAINDER OF NORTH MISSISSIPPI OVER
THE NEXT COUPLE OF HOURS. THESE STORMS COULD BE STRONG WITH GUSTY
WINDS AND HEAVY RAIN. THE BOUNDARY HAS LIMITED HIGH TEMPS ACROSS
THE DELTA THOUGH THE SOUTHERN MOST COUNTIES...FROM TALLAHATCHIE TO
MONROE...HAVE WARMED INTO THE MID 90S WITH HEAT INDEX VALUES
FLIRTING WITH 105 DEGREES. THE REMNANTS OF THE COLD POOL HAVE
RESULTED IN A RELATIVELY NICE DAY ACROSS MUCH OF EASTERN AR...THE
MO BOOTHEEL AND WEST TENNESSEE WHERE TEMPS ARE MOSTLY IN THE 80S
TO AROUND 90. THE AIRMASS STILL QUITE STABLE AND PRECIP FREE.
TONIGHT...LOOKING AT A FAIRLY QUIET EVENING GIVEN THE WORKED OVER
AIRMASS IN PLACE. WENT WITH A 20 POP OVER MOST OF THE AREA AND A
30 POP OVER NE ARKANSAS WHERE THE HRRR IS HINTING AT SOME
DEVELOPMENT BEFORE MIDNIGHT. LOOKING AT ANOTHER POTENTIAL MCS
SCENARIO LATER TONIGHT AS THE LOW LEVEL JET REDEVELOPS OVER
EASTERN OK AND WESTERN AR AND IMPINGES UPON THE WEAK STATIONARY
FRONT ACROSS THE AREA. THIS FRONT HAS BEEN HAVING TROUBLE LIFTING
NORTH OVER THE LAST COUPLE OF DAYS THANKS TO THE RECENT MCS
ACTIVITY AND ASSOCD COLD POOLS. AN AREA OF SHOWERS AND
THUNDERSTORMS SHOULD BLOSSOM OVER SRN MISSOURI AFTER MIDNIGHT AND
THEN HEAD ESE AND SKIRT THE NORTHERN TIER OF THE MIDSOUTH BY
MORNING. POPS WILL DECREASE SHARPLY TOWARD SOUTHERN AREAS OF THE
MIDSOUTH. ANOTHER MILD NIGHT ON TAP WITH LOWS IN THE MID 70S.
THURSDAY...EXPECT THE MCS TO SKIRT THE NORTHERN TIER AND WEAKEN AS
IT SPREADS EAST. BEST CHANCE WILL BE ACROSS NORTHERN AND EASTERN
SECTION WITH LESSER CHANCES TOWARD THE SOUTHWEST. MEX GUIDANCE
CONTINUES TO BE VERY WARM AND WENT CLOSER TO THE COOLER MET
GUIDANCE. EXPECT THAT ANOTHER OUTFLOW BOUNDARY MAY PUSH SOUTH WHICH
WILL HELP KEEP A LID ON TEMPS. AREAS SOUTHWEST OF MEMPHIS ARE
LIKELY TO GET THE WARMEST AND COULD FLIRT WITH HEAT ADVISORY
CRITERIA.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...PATTERN REMAINS SIMILAR
WITH A BROAD UPPER RIDGE ACROSS THE SOUTHERN U.S AND A WEAK
STATIONARY FRONT ACROSS SOUTHERN MISSOURI. EXPECT MCS DEVELOPMENT
ALONG THIS FRONT EACH NIGHT WITH THE BEST CHANCES OF PRECIP ALONG
THE NORTHERN TIER OF THE MIDSOUTH. CONTINUED TO PREFER THE COOLER
MET GUIDANCE THOUGH PARTS OF NORTH MISSISSIPPI AND EAST CENTRAL
ARKANSAS WILL FLIRT WITH HEAT ADVISORY CRITERIA ON FRIDAY.
SATURDAY THROUGH SUNDAY...CONFIDENCE STARTING TO WANE AT THIS
POINT. UPPER RIDGE REMAINS ACROSS THE SOUTHERN U.S. WHILE THE WEAK
BOUNDARY TRIES TO SLIP SOUTH INTO THE MIDSOUTH BUT REALLY DOES
NOT MOVE MUCH. CHANCES FOR SHOWERS AND THUNDERSTORMS EXPECTED ACROSS
THE REGION. MEX STILL TOO WARM.
MONDAY THROUGH WEDNESDAY...MEDIUM RANGE MODELS INDICATE THAT AN
UPPER TROF WILL DEVELOP OVER THE EASTERN U.S. EARLY NEXT WEEK. THE
GFS IS NOT AS DEEP WITH THE TROF WHICH REESTABLISHES NORTHWEST
FLOW ACROSS THE REGION AND KEEPS THE SURFACE BOUNDARY IN THE AREA
RESULTING IN A RENEWED MCS PATTERN. THE ECMWF HAS A DEEPER TROF
AND ACTUALLY PUSHES THE FRONT SOUTH...SHUTTING OFF PRECIP
CHANCES. FOR NOW JUST WENT WITH A COMPROMISE OF 20 POPS AND
SLIGHTLY COOLER THAN NORMAL TEMPS.
SJM
&&
.AVIATION...
00Z TAF CYCLE
VFR CONDITIONS EXPECTED AT ALL THE TAF SITES OUTSIDE OF TEMPO
LIGHT FOG/MVFR VISIBILITIES NEAR SUNRISE AT MKL...JBR AND TUP.
BIGGER CHALLENGE WILL BE THE EXTENT OF THE NEXT FUTURE ROUND OF
CONVECTION CROSSING SOUTHERN MISSOURI. FOR NOW THE GREATEST IMPACT
WILL BE AT JBR AND MKL...WHILE MEM AND TUP SHOULD STAY JUST FAR
ENOUGH SOUTH. CONFIDENCE THOUGH...IS NOT HIGH ENOUGH TO PLACE
THUNDERSTORMS ON STATION AT JBR AND MKL...SO WENT WITH TEMPO
MIDDAY SHOWERS...BECOMING VCTS LATE. WINDS WILL EITHER REMAIN
LIGHT AND VARIABLE OR FROM THE SOUTH AND SOUTHEAST
TONIGHT...INCREASING SLIGHTLY FROM THE SOUTH THURSDAY.
JAB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 77 93 78 94 / 30 30 10 30
MKL 73 88 74 91 / 50 60 30 40
JBR 75 90 75 92 / 50 40 30 40
TUP 75 93 75 93 / 20 40 10 40
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
623 PM CDT WED AUG 7 2013
.UPDATE...
UPDATED FOR 00Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 312 PM CDT WED AUG 7 2013/
DISCUSSION...
THE OUTFLOW BOUNDARY GENERATED FROM THIS MORNINGS MCS CONTINUES TO
PUSH ACROSS NORTHERN MISSISSIPPI. SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED ALONG AND IN ADVANCE OF THE BOUNDARY AND WILL
CONTINUE TO PUSH ACROSS THE REMAINDER OF NORTH MISSISSIPPI OVER
THE NEXT COUPLE OF HOURS. THESE STORMS COULD BE STRONG WITH GUSTY
WINDS AND HEAVY RAIN. THE BOUNDARY HAS LIMITED HIGH TEMPS ACROSS
THE DELTA THOUGH THE SOUTHERN MOST COUNTIES...FROM TALLAHATCHIE TO
MONROE...HAVE WARMED INTO THE MID 90S WITH HEAT INDEX VALUES
FLIRTING WITH 105 DEGREES. THE REMNANTS OF THE COLD POOL HAVE
RESULTED IN A RELATIVELY NICE DAY ACROSS MUCH OF EASTERN AR...THE
MO BOOTHEEL AND WEST TENNESSEE WHERE TEMPS ARE MOSTLY IN THE 80S
TO AROUND 90. THE AIRMASS STILL QUITE STABLE AND PRECIP FREE.
TONIGHT...LOOKING AT A FAIRLY QUIET EVENING GIVEN THE WORKED OVER
AIRMASS IN PLACE. WENT WITH A 20 POP OVER MOST OF THE AREA AND A
30 POP OVER NE ARKANSAS WHERE THE HRRR IS HINTING AT SOME
DEVELOPMENT BEFORE MIDNIGHT. LOOKING AT ANOTHER POTENTIAL MCS
SCENARIO LATER TONIGHT AS THE LOW LEVEL JET REDEVELOPS OVER
EASTERN OK AND WESTERN AR AND IMPINGES UPON THE WEAK STATIONARY
FRONT ACROSS THE AREA. THIS FRONT HAS BEEN HAVING TROUBLE LIFTING
NORTH OVER THE LAST COUPLE OF DAYS THANKS TO THE RECENT MCS
ACTIVITY AND ASSOCD COLD POOLS. AN AREA OF SHOWERS AND
THUNDERSTORMS SHOULD BLOSSOM OVER SRN MISSOURI AFTER MIDNIGHT AND
THEN HEAD ESE AND SKIRT THE NORTHERN TIER OF THE MIDSOUTH BY
MORNING. POPS WILL DECREASE SHARPLY TOWARD SOUTHERN AREAS OF THE
MIDSOUTH. ANOTHER MILD NIGHT ON TAP WITH LOWS IN THE MID 70S.
THURSDAY...EXPECT THE MCS TO SKIRT THE NORTHERN TIER AND WEAKEN AS
IT SPREADS EAST. BEST CHANCE WILL BE ACROSS NORTHERN AND EASTERN
SECTION WITH LESSER CHANCES TOWARD THE SOUTHWEST. MEX GUIDANCE
CONTINUES TO BE VERY WARM AND WENT CLOSER TO THE COOLER MET
GUIDANCE. EXPECT THAT ANOTHER OUTFLOW BOUNDARY MAY PUSH SOUTH WHICH
WILL HELP KEEP A LID ON TEMPS. AREAS SOUTHWEST OF MEMPHIS ARE
LIKELY TO GET THE WARMEST AND COULD FLIRT WITH HEAT ADVISORY
CRITERIA.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...PATTERN REMAINS SIMILAR
WITH A BROAD UPPER RIDGE ACROSS THE SOUTHERN U.S AND A WEAK
STATIONARY FRONT ACROSS SOUTHERN MISSOURI. EXPECT MCS DEVELOPMENT
ALONG THIS FRONT EACH NIGHT WITH THE BEST CHANCES OF PRECIP ALONG
THE NORTHERN TIER OF THE MIDSOUTH. CONTINUED TO PREFER THE COOLER
MET GUIDANCE THOUGH PARTS OF NORTH MISSISSIPPI AND EAST CENTRAL
ARKANSAS WILL FLIRT WITH HEAT ADVISORY CRITERIA ON FRIDAY.
SATURDAY THROUGH SUNDAY...CONFIDENCE STARTING TO WANE AT THIS
POINT. UPPER RIDGE REMAINS ACROSS THE SOUTHERN U.S. WHILE THE WEAK
BOUNDARY TRIES TO SLIP SOUTH INTO THE MIDSOUTH BUT REALLY DOES
NOT MOVE MUCH. CHANCES FOR SHOWERS AND THUNDERSTORMS EXPECTED ACROSS
THE REGION. MEX STILL TOO WARM.
MONDAY THROUGH WEDNESDAY...MEDIUM RANGE MODELS INDICATE THAT AN
UPPER TROF WILL DEVELOP OVER THE EASTERN U.S. EARLY NEXT WEEK. THE
GFS IS NOT AS DEEP WITH THE TROF WHICH REESTABLISHES NORTHWEST
FLOW ACROSS THE REGION AND KEEPS THE SURFACE BOUNDARY IN THE AREA
RESULTING IN A RENEWED MCS PATTERN. THE ECMWF HAS A DEEPER TROF
AND ACTUALLY PUSHES THE FRONT SOUTH...SHUTTING OFF PRECIP
CHANCES. FOR NOW JUST WENT WITH A COMPROMISE OF 20 POPS AND
SLIGHTLY COOLER THAN NORMAL TEMPS.
SJM
&&
.AVIATION...
00Z TAF CYCLE
VFR CONDITIONS EXPECTED AT ALL THE TAF SITES OUTSIDE OF TEMPO
LIGHT FOG/MVFR VISIBILITIES NEAR SUNRISE AT MKL...JBR AND TUP.
BIGGER CHALLENGE WILL BE THE EXTENT OF THE NEXT FUTURE ROUND OF
CONVECTION CROSSING SOUTHERN MISSOURI. FOR NOW THE GREATEST IMPACT
WILL BE AT JBR AND MKL...WHILE MEM AND TUP SHOULD STAY JUST FAR
ENOUGH SOUTH. CONFIDENCE THOUGH...IS NOT HIGH ENOUGH TO PLACE
THUNDERSTORMS ON STATION AT JBR AND MKL...SO WENT WITH TEMPO
MIDDAY SHOWERS...BECOMING VCTS LATE. WINDS WILL EITHER REMAIN
LIGHT AND VARIABLE OR FROM THE SOUTH AND SOUTHEAST
TONIGHT...INCREASING SLIGHTLY FROM THE SOUTH THURSDAY.
JAB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 77 93 78 94 / 30 30 10 30
MKL 73 88 74 91 / 50 60 30 40
JBR 75 90 75 92 / 50 40 30 40
TUP 75 93 75 93 / 20 40 10 40
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
131 PM MDT TUE AUG 6 2013
.SYNOPSIS...
AFTER ANOTHER ROUND OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
THIS EVENING AND OVERNIGHT...WE`LL SEE A DECREASE IN STORM ACTIVITY
THROUGH EARLY FRIDAY AFTERNOON AS HIGH PRESSURE ALOFT SERVES TO CAP
MOST STORM ACTIVITY EXCEPT IN AREA MOUNTAINS. THE RISK OF RAIN WILL
INCREASE FRIDAY NIGHT AND SATURDAY AS A BACKDOOR COLD FRONT MOVES
NEAR THE REGION BY EARLY FRIDAY AND SOUTHEAST SURFACE WINDS BRING
ADDITIONAL MOISTURE. LATER IN THE WEEKEND AND EARLY NEXT WEEK WE
SHOULD RETURN TO A WEAK MONSOON PATTERN WITH THE BEST CHANCES OF
STORMS OVER FAR WESTERN PORTIONS OF THE AREA.
&&
.DISCUSSION...
NOT MUCH CHANGE FROM PREVIOUS THINKING. HRRR BRINGS A CLUSTER OF
STORMS NORTH OVER MEXICO THIS EVENING BUT DIMINISHES ACTIVITY AS
IT APPROACHES EL PASO/HUDSPETH COUNTIES. MAY REGRET IT BUT I PUSHED
POPS ABOVE MOS OVER THAT AREA FOR 1ST PERIOD.
OTHERWISE UPPER HIGH BUILDS BACK INTO REGION FOR TOMORROW THROUGH
MOST OF FRIDAY BEFORE BACKDOOR COLD FRONT MOVES INTO EASTERN PLAINS
OF NM FRIDAY. OVERALL LOWER POPS EXPECTED. GIVEN THE USUAL POOR
PERFORMANCE OF MODELS IN HANDLING THESE BACKDOORS...I WOULDN`T BE
SURPRISED TO HAVE A FRONTAL PASSAGE LATER FRIDAY INTO EARLY
SATURDAY. IN THIS CASE IT WON`T MAKE AS MUCH DIFFERENCE AS IT
USUALLY WOULD SINCE WINDS AHEAD OF THE FRONT WILL SWING TO THE SE
AND RETURN TROPICAL MOISTURE INTO THE REGION. THIS WILL GIVE THE
BEST CHANCE OF SHOWERS AND STORMS AFTER THIS EVENING. IF THE FRONT
ARRIVES RAINFALL WOULD BE HEAVIER AND POSSIBLE SEVERE STORMS WOULD
COME INTO PLAY.
AFTER THAT THE UPPER HIGH AND BUILDS BACK OVER THE AREA GRADUALLY
DIMINISHING STORMS ONCE AGAIN INTO EARLY NEXT WEEK.
&&
.AVIATION...VALID 07/00Z-08/00Z.
MOSTLY VFR THRU THE PERIOD. 00Z-09Z SCATTERED TSRAGS 3SM BKN060CB
TOPS 420. ISOLD AREAS MVFR TO VFR IN/NR TSTMS. SURFACE WINDS
SOUTHWEST 12-22KTS...EXCEPT FOR WIND GUSTS TO 45 KTS NEAR STORMS.
AFT 09Z SCT080 SCT-BKN 100-200. ISOLD -SHRA UNTIL 18Z THEN VERY
ISOLD TS ALL AREAS ESPLY MTNS AND WINDS WSW 15G25KTS.
&&
.FIRE WEATHER...
HIGH PRESSURE ALOFT OVER NORTHEAST TEXAS WILL AGAIN CHANNEL THE
DEEPER MOISTURE MAINLY OVER SOUTHWESTERN NEW MEXICO WITH SCATTERED
AFTERNOON THUNDERSTORMS. AN UPPER TROUGH OVER ARIZONA WILL ALSO
PROVIDE SOME ADDITIONAL DYNAMICS FOR THUNDERSTORM DEVELOPMENT MAINLY
WEST OF THE RIO GRANDE. EAST OF THE RIO GRANDE THUNDERSTORM
DEVELOPMENT WILL BE MORE ISOLATED. THE UPPER TROUGH OVER ARIZONA IS
FORECAST TO MOVE ACROSS NEW MEXICO WEDNESDAY BRINGING WIDELY
SCATTERED THUNDERSTORMS BUT THEN USHER IN DRIER AIR LATER IN THE
DAY. WITH DRIER AIR...THERE WILL BE ONLY A FEW MOUNTAIN
THUNDERSTORMS ON THURSDAY. A POSSIBLE WEAK BACK DOOR FRONT WILL MOVE
IN TO THE AREA EARLY FRIDAY SHIFTING THE WINDS TO THE SOUTHEAST
THEREBY INCREASING THE MOISTURE AT LOWER LEVELS FRIDAY INTO THE
WEEKEND. THIS WILL INCREASE THUNDERSTORMS ACROSS THE AREA WITH
TEMPERATURES STILL REMAINING MAINLY ABOVE NORMAL. MIN RH VALUES
WILL GENERALLY RUN IN THE 25% TO 35% RANGE ALL AREAS TUESDAY AND
WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
EL PASO 74 92 75 94 74 / 30 10 10 10 10
SIERRA BLANCA 68 94 69 95 71 / 30 10 20 20 20
LAS CRUCES 68 91 67 91 69 / 10 10 10 10 10
ALAMOGORDO 71 93 68 94 68 / 20 10 20 10 10
CLOUDCROFT 51 67 51 69 49 / 20 20 20 20 20
TRUTH OR CONSEQUENCES 67 90 67 90 67 / 20 30 10 10 10
SILVER CITY 60 79 58 83 60 / 30 30 10 10 10
DEMING 67 89 64 91 65 / 20 20 10 10 10
LORDSBURG 63 87 63 90 65 / 30 20 10 10 10
WEST EL PASO METRO 74 92 73 94 74 / 30 10 10 10 10
DELL CITY 70 95 69 97 67 / 10 10 10 10 10
FORT HANCOCK 73 95 72 97 72 / 30 10 10 10 20
LOMA LINDA 65 86 66 88 67 / 30 10 10 10 10
FABENS 73 93 71 95 71 / 30 10 10 10 10
SANTA TERESA 70 92 71 93 71 / 30 10 10 10 10
WHITE SANDS HQ 70 92 70 92 69 / 10 10 10 10 10
JORNADA RANGE 67 92 67 92 67 / 10 20 10 10 10
HATCH 66 88 67 89 67 / 20 20 10 10 10
COLUMBUS 66 89 67 91 67 / 20 10 10 10 10
OROGRANDE 72 93 71 94 69 / 20 10 10 10 10
MAYHILL 59 78 58 78 55 / 20 20 20 20 20
MESCALERO 57 79 56 80 56 / 20 20 20 20 20
TIMBERON 57 76 58 77 56 / 20 10 10 20 20
WINSTON 57 78 58 80 57 / 20 40 20 20 10
HILLSBORO 63 84 62 86 63 / 20 30 10 20 10
SPACEPORT 67 90 67 91 67 / 20 20 10 10 10
LAKE ROBERTS 58 78 55 82 58 / 30 40 20 20 10
HURLEY 62 81 61 86 62 / 30 30 10 10 10
CLIFF 61 84 60 88 61 / 40 40 10 20 10
MULE CREEK 56 80 56 85 58 / 40 40 10 10 10
FAYWOOD 63 82 61 85 63 / 20 30 10 10 10
ANIMAS 63 87 65 89 65 / 30 30 20 10 10
HACHITA 64 88 64 90 66 / 30 20 10 10 10
ANTELOPE WELLS 63 86 63 89 65 / 30 30 20 20 10
CLOVERDALE 61 80 61 84 63 / 30 30 20 10 10
&&
.EPZ WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
02/20
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1206 AM CDT TUE AUG 6 2013
.DISCUSSION...
SEE AVIATION FOR 06Z TAF ISSUANCE.
&&
.AVIATION...
MAINLY VFR CONDITIONS EXPECTED THROUGH THE ISSUANCE PERIOD. NAM
AND GFS DEWPOINT DEPRESSION FIELDS STILL HINTING AT LOWER
VISIBILITIES THIS MORNING MAINLY IN THE SOUTHWESTERN ZONES. MOST
LIKELY WILL BE LIMITED TO KLBX AND POSSIBLY KSGR. THIS AFTERNOON
SURFACE LOW PRESSURE WILL FORM IN THE TEXAS PANHANDLE CAUSING THE
PRESSURE GRADIENT TO SLIGHTLY STRENGTHEN KEEPING MODERATE WINDS IN
PLACE. RAP IS SHOWING A SEA AND BAY BREEZE MAKING ITS WAY INLAND
LATER THIS AFTERNOON. GIVEN CONTINUED MODERATE ONSHORE FLOW NOT
SOLD ON RAP SOLUTION. WIND SHIFT FROM SEA BREEZE WILL MOST LIKELY
BE TRANSIENT AS WAS THE CASE TODAY. 23
&&
.PREV DISCUSSION... /ISSUED 852 PM CDT MON AUG 5 2013/
UPDATE...
NO CHANGE TO THE ONGOING HEAT ADVISORY THAT WILL MOST LIKELY BE
IN EFFECT FOR ANOTHER FEW DAYS. THE CURRENT CONFIGURATION OF
COUNTIES IS ON POINT AS THESE WILL BE THE COUNTIES THAT EXPERIENCE
HEAT INDICES AT (OR GREATER THAN) 108 F...OR WHERE HIGHEST AMBIENT
TEMPERATURES WILL OCCUR IN TANDEM WITH HIGHER DEW POINT AIR.
ELSEWHERE...LOWER DEW POINT MIX-DOWN DURING PEAK HEATING WILL KEEP
HEAT INDICES BELOW DEFINED CRITERIA. THE MESSAGE OF HEAT SAFETY
REMAINS THE SAME IF YOU ARE OUTSIDE (NON-SHADED ENVIRONMENT) DURING
THE MID MORNING THROUGH EARLY EVENING HOURS...CORE BEING THAT OF
REMAINING HYDRATED WHILE KEEPING STRENUOUS ACTIVITY TO A MINIMUM.
31
PREV DISCUSSION... /ISSUED 604 PM CDT MON AUG 5 2013/
DISCUSSION...
SEE AVIATION FOR 00Z TAF ISSUANCE.
AVIATION...
MOSTLY VFR CONDITIONS EXPECTED THROUGH THE ISSUANCE PERIOD.
THERE IS ANOTHER CHANCE OF BRIEF MVFR CIGS TUESDAY MORNING AS
SOUNDINGS STILL SHOW AN INVERSION IN PLACE AROUND 900MB. THE
GREATEST CHANCE OF THIS WILL BE KCXO NORTHWARDS. IN THE
SOUTHWESTERN ZONES THERE IS ALSO A CHANCE OF SOME BRIEF MORNING
LOW VISIBILITIES. BOTH NAM AND GFS DEW POINT DEPRESSION FIELDS
SHOW THIS ALBEIT A TAD OVERDONE PROBABLY. 23
PREV DISCUSSION... /ISSUED 325 PM CDT MON AUG 5 2013/
DISCUSSION...
A VERY WARM AFTERNOON ACROSS SOUTHEAST TEXAS AS SOUTHWESTERLY LOW
LEVEL WINDS HAVE ALLOWED INLAND TEMPERATURES TO CLIMB INTO THE
UPPER 90S AND LOW 100S. TEMPERATURES ALONG THE COAST ARE ONLY IN
THE LOW TO MID 90S BUT RISING DEW POINTS BEHIND THE SEA BREEZE
HAVE PUSHED APPARENT TEMPERATURES ABOVE 105 DEGREES ALONG THE
COAST. THE HEAT ADVISORY HAS BEEN EXTENDED THROUGH TUESDAY
AFTERNOON FOR THE CURRENTLY AFFECTED AREA. AREAS FURTHER INLAND
HAVE MIXED OUT ENOUGH TO KEEP VALUES BELOW THE 108 DEGREE APPARENT
TEMPERATURE REQUIRED FOR ISSUANCE OF A HEAT ADVISORY.
NO RELIEF EXPECTED IN THE NEXT FEW DAYS AS TEMPERATURES WILL
REMAIN UNSEASONABLY WARM. STRONG SOUTHWESTERLY FLOW BELOW 700MB
WILL CONTINUE THROUGH MID WEEK WHICH WILL DRIVE TEMPERATURES INTO
THE TRIPLE DIGITS FOR MANY AREAS EACH AFTERNOON. PRECIPITATION
CHANCES REMAIN AT OR NEAR ZERO THROUGH THE MIDDLE OF THE WEEK AS
THE UPPER LEVEL RIDGE REMAINS FIRMLY PLANTED ACROSS THE STATE.
TEMPERATURES WILL BEGIN TO BACK DOWN JUST A BIT ON FRIDAY AS LOW
LEVEL MOISTURE BEGINS TO INCREASE IN ASSOCIATION WITH AN INVERTED
UPPER TROUGH WHICH WILL TREK WESTWARD ACROSS THE GULF OF MEXICO.
MODELS ARE NOW IN BETTER AGREEMENT WITH THIS FEATURE UNDERCUTTING
THE UPPER RIDGE ACROSS OUR AREA AND BRINGING INCREASED RAIN
CHANCES TO SOUTHEAST TEXAS FOR THIS WEEKEND. GIVEN THE INCREASE
IN MODEL AGREEMENT HAVE BUMPED POPS UP SLIGHTLY ON SATURDAY AND
SUNDAY OVER THE SOUTHERN HALF OF THE AREA. A RETURN TO DRIER AND
WARMER TEMPERATURES IS EXPECTED EARLY NEXT WEEK AS THE TROUGH
MOVES INTO MEXICO AND UPPER LEVEL RIDGING BECOMES REESTABLISHED
OVER THE REGION. 38
MARINE...
LIGHT TO MODERATE ONSHORE WINDS WILL PERSIST FOR MUCH OF THE WEEK
AND CONTINUE ON INTO THE WEEKEND. SPEEDS MIGHT REACH CAUTION LEVELS
TUESDAY AND TUESDAY NIGHT. AT THE VERY END OF THE WEEK AND OVER THE
WEEKEND...A WESTWARD MOVING TROPICAL WAVE IS EXPECTED TO BRING
INCREASING SHOWER AND THUNDERSTORM CHANCES TO THE AREA. 42
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 101 78 102 79 102 / 10 10 10 0 0
HOUSTON (IAH) 98 77 100 79 100 / 10 10 10 0 0
GALVESTON (GLS) 93 81 94 82 94 / 10 10 10 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...HEAT ADVISORY UNTIL 9 PM CDT TUESDAY FOR THE FOLLOWING ZONES:
BRAZORIA...CHAMBERS...GALVESTON...HARRIS...JACKSON...
LIBERTY...MATAGORDA.
GM...NONE.
&&
$$
DISCUSSION...31
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
946 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. SOUTHERLY
RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL MOISTURE UP THE
EASTERN SEABOARD. A FRONT MOVES INTO THE MOUNTAINS BY THURSDAY
NIGHT INTO FRIDAY AND SLOWLY SHIFTS TO THE SOUTH OF US AFTER
THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 940 PM EDT WEDNESDAY...
PRECIPITATION HAS ENDED ACROSS MOST OF THE REGION. SOME LINGERING
LIGHT RAIN WAS WITHIN THE JAMES RIVER BASIN AND PARTS OF THE LOWER
DAN RIVER BASIN. BY MIDNIGHT...WE EXPECT MOST...IF NOT ALL...OF
THE REAMINING PRECIPITATION TO HAVE DISSIPATED OR EXITED THE
REGION. SHOWERS RETURN TO THE FORECAST LATER TONIGHT IN THE WEST
IN ADVANCE OF THE NEXT APPROACHING SHORTWAVE TROUGH. HAVE MADE
LITTLE IF ANY ADJUSTMENTS TO THE OVERNIGHT TEMPERATURES AND ADDED
A FEW MORE AREAS OF FOG THAN PREVIOUSLY FORECAST.
AS OF 635 PM EDT WEDNESDAY...
NOT A LOT OF BIG CHANGES EARLY THIS EVENING. OUR FOCUS FOR THE
BEST COVERAGE OF SHOWERS AND STORMS HEADING INTO THE EVENING
REMAINS ACROSS THE MOUNTAINS...AND PERHAPS ONE OR TWO TIERS OF
COUNTIES EAST OF THE CREST OF THE BLUE RIDGE. LATEST LOCAL AND
REGIONAL RADAR TRENDS SHOW THE FORECAST DECREASE IN COVERAGE AND
INTENSITY. THIS TREND IS EXPECTED TO CONTINUE THROUGH THE EVENING.
HAVE TWEAKED TRENDS IN HOURLY TEMPERATURES AND DEW POINTS TO
REFLECT THE LATEST OBSERVATIONS AND EXPECTED TRENDS THROUGH THE
EVENING.
AS OF 340 PM EDT WEDNESDAY...
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING
WILL DIMINISH WITH THE LOSS OF SOLAR HEATING TONIGHT. CONTINUED THE
MENTION OF HEAVY RAIN WITH THUNDERSTORMS BECAUSE SOME OF THE
THUNDERSTORMS COULD BE EFFICIENT RAIN PRODUCERS. HOWEVER...NOT
EXPECTING WIDESPREAD FLASH FLOODING WITH 1 FFG RELATIVELY HIGH
RANGING FROM 1.6 TO 3 INCHES. LOCAL WATER PROBLEMS ARE POSSIBLE
DEPENDING ON EVOLUTION AND TRACK OF THUNDERSTORMS. PLACED THE
HIGHEST POPS IN THE WEST AND TAPER OFF AS ONE HEAD SOUTHEAST TONIGHT.
THERE IS THE POTENTIAL FOR SOME STORMS MOVE INTO THE WESTERN CWA
LATE TONIGHT INTO THURSDAY MORNING AS DEPICTED ON HRRR AND ECMWF.
WENT WITH WARMER MOS LOW TEMPERATURES FROM THE LOWER 60S IN THE
MOUNTAINS TO AROUND 70 DEGREES IN THE SOUTHEAST.
ISOLATED SHOWERS THURSDAY MORNING WILL BECOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE MOUNTAINS THURSDAY AFTERNOON AND EVENING AS
WEAK DISTURBANCES PASS FROM WEST TO EAST IN THE ZONAL UPPER LEVEL
WIND FLOW. WITH PRECIPITABLE WATER FORECAST AROUND 2 INCHES AND SOME
CAPE...THERE COULD BE SOME THUNDERSTORMS WITH LOCALLY HEAVY RAINS.
A FEW OF THE STORMS COULD BE STRONG TO SEVERE ACROSS THE NORTH AS
SPC HAS A 5 PERCENT CHANCE FOR A SEVERE STORMS ON THURSDAY. PLAYED
HIGH TEMPERATURES ON THURSDAY FROM THE MID 70S IN THE MOUNTAINS TO
THE MID 80S IN THE PIEDMONTS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 400 PM EDT WEDNESDAY...
WITH A CLOSED LOW OVER THE UPPER GREAT LAKES AND A BROAD UPPER RIDGE
FROM THE WESTERN ATLANTIC THROUGH THE ARKLATEX...A STATIONARY
BOUNDARY WILL REMAIN NEAR OUR REGION THROUGH THE PERIOD. EVERY DAY
WILL FEATURE SHOWERS AND STORMS...WITH PERHAPS FRIDAY BEING THE
WETTEST DAY. THE BOUNDARY PERHAPS SINKS A LITTLE FURTHER SOUTH AND
WITH A WESTERLY/DOWNSLOPING WIND DEVELOPING...THERE MAY BE LESS
COVERAGE AND MORE FOCUS ACROSS SOUTHSIDE VIRGINIA AND THE NC
PIEDMONT. WITH LITTLE OR NO FLOW...BACKBUILDING AND/OR COLLIDING
STORMS...AND HIGH PWATS...THE OPPORTUNITY FOR FLASH FLOODING WILL
CONTINUE WITH A FLASH FLOOD WATCH PERHAPS NEEDED AT SOME POINT BASED
ON ANTECEDENT CONDITIONS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 400 PM EDT WEDNESDAY...
WITH THE UPPER RIDGE CONSOLIDATING AND MOVING TO THE FOUR CORNERS
REGION...TROUGHING WILL DEEPEN AND STRENGTHEN ACROSS THE EAST AND
MIDDLE ATLANTIC. WITH THE COOLER TEMPS AND LESS MOISTURE...SHOWERS
AND STORMS WILL BECOME LESS LIKELY AND SUPPRESSED SOUTH AS THE WEEK
WEARS ON. HOWEVER...CAN`T TOTALLY RULE OUT A FEW POP UP SHOWERS
REGIONWIDE WITH SUCH CHILLY TEMPS ALOFT FOR THIS TIME OF YEAR.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
AS OF 640 PM EDT WEDNESDAY...
CONFIDENCE IS HIGH THAT CURRENT SHRA/TSRA ACTITIVY ACROSS THE
REGION WILL CONTINUE TO WANE AS WE PROGRESS THROUGH THE EVENING
HOURS. ALSO AT HIGH CONFIDENCE IS THE TREND FOR CIGS/VSBYS TO
TREND FROM MAINLY A MIX OF MVFR/VFR CONDITIONS TO LIFR/IFR
CONDITIONS BY 10Z/6AM THURSDAY.
PRECIPTIATION WILL BE ON THE INCREASE TOWARD THURSDAY
MORNING...EPSECIALLY OVER THE MOUNTAIN WITH THE APPROACH OF THE
NEXT SHORWAVE TROUGH. COVERAGE WILL INCREASE THROUGH THE DAY
THURSDAY WITH CONFIDENCE HIGH THAT THE BEST COVERAGE WILL BE OVER
THE MOUNTAINS. FLIGHT CATEGORIES WILL GRADUALLY IMPROVE THROUGH
THE MORNING HOURS WITH MOST AREAS MVFR/VFR BY 16Z/NOON.
AS OF 130 PM EDT WEDNESDAY...
BY FRIDAY-SUNDAY A FRONTAL BOUNDARY WILL BE IN THE VICINITY TO
SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP TERMINALS DEALING WITH
DELAYS DUE TO STORMS...BUT OVER HALF THE TIME...IT SHOULD BE VFR.
DRIER AIR PUSHES INTO NORTH ON MONDAY WITH SCATTERED CONVECTION
STILL POSSIBLE ESPECIALLY IN THE SOUTH.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...DS/KK
SHORT TERM...KM
LONG TERM...KM
AVIATION...DS/WP
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
742 PM EDT WED AUG 7 2013
.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH THURSDAY. SOUTHERLY
RETURN FLOW AROUND THE HIGH WILL DRAW TROPICAL MOISTURE UP THE
EASTERN SEABOARD. A FRONT MOVES INTO THE MOUNTAINS BY THURSDAY
NIGHT INTO FRIDAY AND SLOWLY SHIFTS TO THE SOUTH OF US AFTER
THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY/...
AS OF 635 PM EDT WEDNESDAY...
NOT A LOT OF BIG CHANGES EARLY THIS EVENING. OUR FOCUS FOR THE
BEST COVERAGE OF SHOWERS AND STORMS HEADING INTO THE EVENING
REMAINS ACROSS THE MOUNTAINS...AND PERHAPS ONE OR TWO TIERS OF
COUNTIES EAST OF THE CREST OF THE BLUE RIDGE. LATEST LOCAL AND
REGIONAL RADAR TRENDS SHOW THE FORECAST DECREASE IN COVERAGE AND
INTENSITY. THIS TREND IS EXPECTED TO CONTINUE THROUGH THE EVENING.
HAVE TWEAKED TRENDS IN HOURLY TEMPERATURES AND DEW POINTS TO
REFLECT THE LATEST OBSERVATIONS AND EXPECTED TRENDS THROUGH THE
EVENING.
AS OF 340 PM EDT WEDNESDAY...
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING
WILL DIMINISH WITH THE LOSS OF SOLAR HEATING TONIGHT. CONTINUED THE
MENTION OF HEAVY RAIN WITH THUNDERSTORMS BECAUSE SOME OF THE
THUNDERSTORMS COULD BE EFFICIENT RAIN PRODUCERS. HOWEVER...NOT
EXPECTING WIDESPREAD FLASH FLOODING WITH 1 FFG RELATIVELY HIGH
RANGING FROM 1.6 TO 3 INCHES. LOCAL WATER PROBLEMS ARE POSSIBLE
DEPENDING ON EVOLUTION AND TRACK OF THUNDERSTORMS. PLACED THE
HIGHEST POPS IN THE WEST AND TAPER OFF AS ONE HEAD SOUTHEAST TONIGHT.
THERE IS THE POTENTIAL FOR SOME STORMS MOVE INTO THE WESTERN CWA
LATE TONIGHT INTO THURSDAY MORNING AS DEPICTED ON HRRR AND ECMWF.
WENT WITH WARMER MOS LOW TEMPERATURES FROM THE LOWER 60S IN THE
MOUNTAINS TO AROUND 70 DEGREES IN THE SOUTHEAST.
ISOLATED SHOWERS THURSDAY MORNING WILL BECOME SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE MOUNTAINS THURSDAY AFTERNOON AND EVENING AS
WEAK DISTURBANCES PASS FROM WEST TO EAST IN THE ZONAL UPPER LEVEL
WIND FLOW. WITH PRECIPITABLE WATER FORECAST AROUND 2 INCHES AND SOME
CAPE...THERE COULD BE SOME THUNDERSTORMS WITH LOCALLY HEAVY RAINS.
A FEW OF THE STORMS COULD BE STRONG TO SEVERE ACROSS THE NORTH AS
SPC HAS A 5 PERCENT CHANCE FOR A SEVERE STORMS ON THURSDAY. PLAYED
HIGH TEMPERATURES ON THURSDAY FROM THE MID 70S IN THE MOUNTAINS TO
THE MID 80S IN THE PIEDMONTS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 400 PM EDT WEDNESDAY...
WITH A CLOSED LOW OVER THE UPPER GREAT LAKES AND A BROAD UPPER RIDGE
FROM THE WESTERN ATLANTIC THROUGH THE ARKLATEX...A STATIONARY
BOUNDARY WILL REMAIN NEAR OUR REGION THROUGH THE PERIOD. EVERY DAY
WILL FEATURE SHOWERS AND STORMS...WITH PERHAPS FRIDAY BEING THE
WETTEST DAY. THE BOUNDARY PERHAPS SINKS A LITTLE FURTHER SOUTH AND
WITH A WESTERLY/DOWNSLOPING WIND DEVELOPING...THERE MAY BE LESS
COVERAGE AND MORE FOCUS ACROSS SOUTHSIDE VIRGINIA AND THE NC
PIEDMONT. WITH LITTLE OR NO FLOW...BACKBUILDING AND/OR COLLIDING
STORMS...AND HIGH PWATS...THE OPPORTUNITY FOR FLASH FLOODING WILL
CONTINUE WITH A FLASH FLOOD WATCH PERHAPS NEEDED AT SOME POINT BASED
ON ANTECEDENT CONDITIONS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 400 PM EDT WEDNESDAY...
WITH THE UPPER RIDGE CONSOLIDATING AND MOVING TO THE FOUR CORNERS
REGION...TROUGHING WILL DEEPEN AND STRENGTHEN ACROSS THE EAST AND
MIDDLE ATLANTIC. WITH THE COOLER TEMPS AND LESS MOISTURE...SHOWERS
AND STORMS WILL BECOME LESS LIKELY AND SUPPRESSED SOUTH AS THE WEEK
WEARS ON. HOWEVER...CAN`T TOTALLY RULE OUT A FEW POP UP SHOWERS
REGIONWIDE WITH SUCH CHILLY TEMPS ALOFT FOR THIS TIME OF YEAR.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 640 PM EDT WEDNESDAY...
CONFIDENCE IS HIGH THAT CURRENT SHRA/TSRA ACTITIVY ACROSS THE
REGION WILL CONTINUE TO WANE AS WE PROGRESS THROUGH THE EVENING
HOURS. ALSO AT HIGH CONFIDENCE IS THE TREND FOR CIGS/VSBYS TO
TREND FROM MAINLY A MIX OF MVFR/VFR CONDITIONS TO LIFR/IFR
CONDITIONS BY 10Z/6AM THURSDAY.
PRECIPTIATION WILL BE ON THE INCREASE TOWARD THURSDAY
MORNING...EPSECIALLY OVER THE MOUNTAIN WITH THE APPROACH OF THE
NEXT SHORWAVE TROUGH. COVERAGE WILL INCREASE THROUGH THE DAY
THURSDAY WITH CONFIDENCE HIGH THAT THE BEST COVERAGE WILL BE OVER
THE MOUNTAINS. FLIGHT CATEGORIES WILL GRADUALLY IMPROVE THROUGH
THE MORNING HOURS WITH MOST AREAS MVFR/VFR BY 16Z/NOON.
AS OF 130 PM EDT WEDNESDAY...
BY FRIDAY-SUNDAY A FRONTAL BOUNDARY WILL BE IN THE VICINITY TO
SEE MORE COVERAGE AREA WIDE. THIS WILL KEEP TERMINALS DEALING WITH
DELAYS DUE TO STORMS...BUT OVER HALF THE TIME...IT SHOULD BE VFR.
DRIER AIR PUSHES INTO NORTH ON MONDAY WITH SCATTERED CONVECTION
STILL POSSIBLE ESPECIALLY IN THE SOUTH.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...DS/KK
SHORT TERM...KM
LONG TERM...KM
AVIATION...DS/WP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
620 AM CDT TUE AUG 6 2013
.UPDATE...
ISSUED AT 620 AM CDT TUE AUG 6 2013
FOG HAS THICKEN UP OVER SOUTHWEST WI...AND PER OBS AND CALLS TO
DISPATCH...1/4 MILE VSBYS WERE FAIRLY COMMON. EXPANDED THE DENSE FOG
ADV AS A RESULT. BUFKIT SOUNDINGS CONTINUE TO SUGGEST THAT WINDS
WILL START TO MIX OUT THE FOG BY 9-10 AM.
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE AUG 6 2013
AT 3 AM...DENSE FOG WAS REPORTED ACROSS MUCH OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA...IN THE WISCONSIN RIVER VALLEY...
AND ON THE RIDGE TOPS SURROUNDING THE MISSISSIPPI RIVER. THE
VISIBILITIES AT OUR OFFICE IS LESS THAN A QUARTER MILE. AS A TROUGH
MOVES THROUGH NORTHEAST IOWA AND WESTERN WISCONSIN EARLY THIS
MORNING...THE WINDS WILL INCREASE ALOFT AND SOME DRIER AIR WILL
HELP DISSIPATE THE FOG BETWEEN 06.10Z AND 06.14Z.
FOR THIS AFTERNOON AND TONIGHT...WE WILL HAVE TO WATCH 2 AREAS OF
CONVECTION WHICH IS LOCATED CURRENTLY OVER THE DAKOTAS. THE LATEST
RAP SHOWS THAT 850 MB MOISTURE TRANSPORT INTO THESE AREAS WILL
KEEP THIS CONVECTION GOING THROUGH THE MORNING. THESE AREAS ARE
CAUSING HAVOC ON THE MESO MODELS. BOTH THE 06.00Z NMM AND ARW ARE
SHOWING THAT THE CONVECTION OVER NORTH DAKOTA IS THE MOST DOMINANT
AND THEY BRING A ROBUST AREA OF SHOWERS AND THUNDERSTORMS INTO
SOUTHEAST MINNESOTA AND NORTHEAST IOWA. MEANWHILE THE HRRR SHOW
THAT THE CONVECTION ACROSS NORTH DAKOTA WILL MOVE EAST SOUTHEAST
ACROSS NORTHERN MINNESOTA. MEANWHILE THE CONVECTION ACROSS WESTERN
SOUTH DAKOTA WILL DEVELOP A MESOSCALE VORTICITY WILL DEVELOP OUT
OF THIS THUNDERSTORM COMPLEX. LOOKING AT THE LATEST WATER VAPOR
AND RADAR IMAGERY THIS ACTUALLY MAKES A LOT OF SENSE. AS THIS
VORTICITY ENCOUNTERS INCREASING CAPES ACROSS EASTERN SOUTH
DAKOTA...NORTHWEST IOWA...AND SOUTHWEST MINNESOTA...THERE WILL BE
THE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS LATE THIS MORNING
AND AFTERNOON. ADDITIONAL LINES OF THUNDERSTORMS WILL LIKELY
DEVELOP AHEAD OF AN APPROACHING COLD FRONT ACROSS WEST CENTRAL
AND NORTHWEST MINNESOTA. THERE IS MORE THAN ADEQUATE SHEAR FOR THESE
THUNDERSTORMS TO BECOME ORGANIZED. THIS WILL INCLUDE SPLITTING
SUPERCELLS AND BOWING LINE SEGMENTS. THE MAIN SEVERE WEATHER
THREAT ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND WEST
CENTRAL AND SOUTHWEST WISCONSIN WILL BE LIKELY LARGE HAIL...DAMAGING
WINDS...AND POSSIBLY ISOLATED TORNADOES FROM 6 PM THROUGH MIDNIGHT.
AS THE COLD FRONT SWEEPS THROUGH THE AREA OVERNIGHT...THE THREAT
FOR SHOWERS AND THUNDERSTORMS WILL QUICKLY COME TO AN END ACROSS
THE AREA FROM NORTHWEST TO SOUTHEAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CDT TUE AUG 6 2013
ON THURSDAY NIGHT AND FRIDAY...THE 06.00Z MODELS ARE IN GOOD
AGREEMENT THAT A VIGOROUS SHORT WAVE TROUGH WILL MOVE EAST ACROSS
NORTHERN MINNESOTA AND UPPER MICHIGAN. AS THIS OCCURS...A COLD
FRONT WILL MOVE SOUTH THROUGH THE NORTHERN HALVES OF MINNESOTA AND
WISCONSIN. THERE LOOKS TO BE ENOUGH INSTABILITY AND SYNOPTIC
FORCING FOR THE DEVELOPMENT OF SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND AHEAD OF THIS FRONT. WITH THE BEST 0-6 KM
SHEAR IN THE WAKE OF THIS SYSTEM...NOT EXPECTING TO SEE ANY SEVERE
WEATHER FROM THIS SYSTEM.
FROM LATE SATURDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO
STRUGGLE WITH THE LOCATION AND TIMING OF SHORT WAVES MOVING
OUT OF THE NORTHERN PLAINS. AS A RESULT CONFIDENCE IN THE TIMING
AND LOCATION OF PRECIPITATION DURING THIS TIME PERIOD IS LOWER
THAN NORMAL. AS A RESULT...JUST WENT WITH THE ALL BLEND FOR THIS
TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 620 AM CDT MON AUG 5 2013
SFC TROUGH HELPED CLEAR DENSE FOG FROM KRST EARLY THIS MORNING...BUT
MORE FG THEN FORMED A FEW MILES BEHIND THE TROUGH - WHERE THE SKIES
WERE CLEAR. THIS COULD STILL IMPACT KRST FOR A COUPLE HOURS EARLY
THIS MORNING...MOSTLY IFR/MVFR. KLSE WILL ALSO DEAL WITH SOME BR
FOR A FEW HOURS.
COLD FRONT WILL SWEEP IN FROM THE WEST TONIGHT...WITH A BAND OF
SHRA/TS ALONG AND AHEAD OF IT. THERE WILL BE SOME LOWER VSBYS WITH
THE STORMS...AND SOME CLOUD BASE LOWERING. WILL KEEP VFR VCTS/TSRA
FOR THE MOMENT...ALLOWING FOR LATER UPDATES WHEN TIMING CAN BE
BETTER REFINED. COULD BE SOME ENHANCED GUSTINESS AROUND THE STORMS
TOO.
THE FRONT LOOKS TO TRACK ACROSS KRST/KLSE IN THE 06-09Z TIME FRAME.
MODEL RH FIELDS SUGGESTING THAT LOW STRATUS COULD FOLLOW/DEVELOP IN
THE WAKE OF THE FRONT...ESPECIALLY THE NAM. FORECAST CONFIDENCE
SHAKY ON JUST HOW LOW CIGS COULD GO...BUT WILL TREND THEM
DOWNWARD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR WIZ053>055-
061.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ094-095.
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ096.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>010-
018-019-029.
DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ011-030.
&&
$$
UPDATE.......RIECK
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
358 AM CDT TUE AUG 6 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT TUE AUG 6 2013
AT 3 AM...DENSE FOG WAS REPORTED ACROSS MUCH OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA...IN THE WISCONSIN RIVER VALLEY...
AND ON THE RIDGE TOPS SURROUNDING THE MISSISSIPPI RIVER. THE
VISIBILITIES AT OUR OFFICE IS LESS THAN A QUARTER MILE. AS A TROUGH
MOVES THROUGH NORTHEAST IOWA AND WESTERN WISCONSIN EARLY THIS
MORNING...THE WINDS WILL INCREASE ALOFT AND SOME DRIER AIR WILL
HELP DISSIPATE THE FOG BETWEEN 06.10Z AND 06.14Z.
FOR THIS AFTERNOON AND TONIGHT...WE WILL HAVE TO WATCH 2 AREAS OF
CONVECTION WHICH IS LOCATED CURRENTLY OVER THE DAKOTAS. THE LATEST
RAP SHOWS THAT 850 MB MOISTURE TRANSPORT INTO THESE AREAS WILL
KEEP THIS CONVECTION GOING THROUGH THE MORNING. THESE AREAS ARE
CAUSING HAVOC ON THE MESO MODELS. BOTH THE 06.00Z NMM AND ARW ARE
SHOWING THAT THE CONVECTION OVER NORTH DAKOTA IS THE MOST DOMINANT
AND THEY BRING A ROBUST AREA OF SHOWERS AND THUNDERSTORMS INTO
SOUTHEAST MINNESOTA AND NORTHEAST IOWA. MEANWHILE THE HRRR SHOW
THAT THE CONVECTION ACROSS NORTH DAKOTA WILL MOVE EAST SOUTHEAST
ACROSS NORTHERN MINNESOTA. MEANWHILE THE CONVECTION ACROSS WESTERN
SOUTH DAKOTA WILL DEVELOP A MESOSCALE VORTICITY WILL DEVELOP OUT
OF THIS THUNDERSTORM COMPLEX. LOOKING AT THE LATEST WATER VAPOR
AND RADAR IMAGERY THIS ACTUALLY MAKES A LOT OF SENSE. AS THIS
VORTICITY ENCOUNTERS INCREASING CAPES ACROSS EASTERN SOUTH
DAKOTA...NORTHWEST IOWA...AND SOUTHWEST MINNESOTA...THERE WILL BE
THE REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS LATE THIS MORNING
AND AFTERNOON. ADDITIONAL LINES OF THUNDERSTORMS WILL LIKELY
DEVELOP AHEAD OF AN APPROACHING COLD FRONT ACROSS WEST CENTRAL
AND NORTHWEST MINNESOTA. THERE IS MORE THAN ADEQUATE SHEAR FOR THESE
THUNDERSTORMS TO BECOME ORGANIZED. THIS WILL INCLUDE SPLITTING
SUPERCELLS AND BOWING LINE SEGMENTS. THE MAIN SEVERE WEATHER
THREAT ACROSS SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND WEST
CENTRAL AND SOUTHWEST WISCONSIN WILL BE LIKELY LARGE HAIL...DAMAGING
WINDS...AND POSSIBLY ISOLATED TORNADOES FROM 6 PM THROUGH MIDNIGHT.
AS THE COLD FRONT SWEEPS THROUGH THE AREA OVERNIGHT...THE THREAT
FOR SHOWERS AND THUNDERSTORMS WILL QUICKLY COME TO AN END ACROSS
THE AREA FROM NORTHWEST TO SOUTHEAST.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM CDT TUE AUG 6 2013
ON THURSDAY NIGHT AND FRIDAY...THE 06.00Z MODELS ARE IN GOOD
AGREEMENT THAT A VIGOROUS SHORT WAVE TROUGH WILL MOVE EAST ACROSS
NORTHERN MINNESOTA AND UPPER MICHIGAN. AS THIS OCCURS...A COLD
FRONT WILL MOVE SOUTH THROUGH THE NORTHERN HALVES OF MINNESOTA AND
WISCONSIN. THERE LOOKS TO BE ENOUGH INSTABILITY AND SYNOPTIC
FORCING FOR THE DEVELOPMENT OF SCATTERED SHOWERS AND
THUNDERSTORMS ALONG AND AHEAD OF THIS FRONT. WITH THE BEST 0-6 KM
SHEAR IN THE WAKE OF THIS SYSTEM...NOT EXPECTING TO SEE ANY SEVERE
WEATHER FROM THIS SYSTEM.
FROM LATE SATURDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO
STRUGGLE WITH THE LOCATION AND TIMING OF SHORT WAVES MOVING
OUT OF THE NORTHERN PLAINS. AS A RESULT CONFIDENCE IN THE TIMING
AND LOCATION OF PRECIPITATION DURING THIS TIME PERIOD IS LOWER
THAN NORMAL. AS A RESULT...JUST WENT WITH THE ALL BLEND FOR THIS
TIME PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1124 PM CDT MON AUG 5 2013
CONDITIONS CONTINUE TO DETERIORATE ACROSS THE REGION AS A LOW END
MVFR TO IFR STRATUS DECK STALLED ALONG AND EAST OF THE MISSISSIPPI
RIVER. FURTHER WEST OF THIS STRATUS IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA...SKIES HAVE CLEARED WITH FOG FORMING DUE TO THE
LIGHT WINDS AND RECENT RAINS. EXPECT THAT CONDITIONS WILL CONTINUE
TO DROP THROUGH THE NIGHT WITH VISIBILITY DROPPING TO A QUARTER OF
A MILE AT TIMES...THOUGH LSE HAS BEEN AT 10SM ALL EVENING DESPITE
HAVING A 1KFT DECK OVERHEAD. WARMER AIR WILL MOVE IN TOMORROW
MORNING AND WILL HELP TO IMPROVE CONDITIONS RATHER QUICKLY.
SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP AHEAD OF A
COLD FRONT TUESDAY AFTERNOON/EVENING ACROSS MINNESOTA. SOME BRIEF
DROPS TO IFR WILL BE POSSIBLE AS THESE STORMS ROLL THROUGH
SOMETIME IN THE LATE AFTERNOON AND EARLY EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ086-087-
094-095.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>010-
018-019-029.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
120 AM CDT TUE AUG 6 2013
.UPDATE...
ISSUED AT 120 AM CDT TUE AUG 6 2013
FOG CONTINUED TO THICKEN ACROSS AREAS WEST OF THE MISSISSIPPI RIVER
EARLY THIS MORNING...PER SFC OBS WITH SUPPORT FROM CALLS TO LOCAL
DISPATCHES...SO HAVE ISSUED A DENSE FOG ADV THROUGH 14Z. THE FOG MAY
CLEAR A FEW HOURS BEFORE THAT THOUGH AS A WEAK SFC TROUGH MOVES IN.
WILL KEEP AN EYE ON TRENDS AND CLEAR THE ADV EARLY IF NEEDED.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE NEXT 24 TO 36 HOURS WILL FEATURE A MORE ACTIVE PERIOD WITH A
FEW WEATHER SYSTEMS TO CONTEND WITH INCLUDING PRECIPITATION
CHANCES THIS EVENING...FOG OVERNIGHT...AND THEN SEVERE THREAT
TUESDAY AFTERNOON/EVENING.
LATEST WATER VAPOR COMBINED WITH RAP 500MB HEIGHTS SHOW BROAD
NORTHWEST FLOW EAST OF THE ROCKIES...WITH NUMEROUS EMBEDDED
SHORTWAVE TROUGHS. ONE CURRENTLY MOVING THROUGH
MINNESOTA/IOWA...WHILE UPSTREAM ACROSS ALBERTA SITS A MORE VIGOROUS
WAVE. FINALLY...A CLOSED POLAR VORTEX RESIDES NEAR HUDSON BAY.
FOR THIS EVENING INTO TONIGHT...WILL CARRY A SLIGHT CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS UNTIL UPPER LEVEL SHORTWAVE
COMPLETELY EXITS THE AREA. DESPITE SURFACE TROUGH LAGGING
BEHIND...AND BUILDING INSTABILITY WITH CLEARING SKIES...SUBSIDENCE
IN THE WAKE OF THE UPPER LEVEL SHORTWAVE AND SOME LOW TO MID LEVEL
DRYING SHOULD PRECLUDE THE DEVELOPMENT OF ADDITIONAL SHOWERS/STORMS.
HAVE ADDED PATCHY TO AREAS OF FOG FOR PARTS OF WISCONSIN...INCLUDING
THE MS AND WISCONSIN RIVER VALLEYS OVERNIGHT AS A WEAK SURFACE
HIGH BUILDS IN THE WAKE OF THE DEPARTING SYSTEM AND AHEAD OF THE
APPROACHING COLD FRONT. NICE SETUP WITH TODAY/S COOL...CLOUDY
CONDITIONS AND RECENT RAINFALL...THEN CLEARING SKIES LATE THIS
EVENING. SURFACE WIND FIELD DROPS TO 5 KTS OR LESS...AND SOUNDINGS
SHOW DECENT BOUNDARY LAYER SATURATION THOUGH TRY TO SHOW A STIFF
BREEZE AT ABOUT 500 FT. COULD BE A MORE WIDESPREAD FOG SCENARIO
INSTEAD OF JUST THE RIVER VALLEYS...SOMETHING TO WATCH THIS
EVENING.
THE ALBERTA SHORTWAVE TROUGH THEN TAKES AIM ON THE AREA...AND WILL
BE THE FOCUS FOR PUSHING THROUGH A SURFACE COLD FRONT TUESDAY
EVENING. BUILDING INSTABILITY DURING THE DAY IS SOMEWHAT CONDITIONAL
ON AN EARLY MORNING MCS EXPECTED WELL TO OUR WEST...BUT BY MID
AFTERNOON...MUCAPE BETWEEN 1500 AND 2000 J/KG COULD BE REALIZED. THE
SHEAR ENVIRONMENT IS MORE THAN SUFFICIENT FOR SEVERE STORMS AS 250
MB JET MAX OVERHEAD PUTS 40 TO 50 KTS OF EFFECTIVE SHEAR ACROSS MUCH
OF THE AREA...AND THE LOW-LEVELS HAVE FAVORABLE LAPSE RATES.
HODOGRAPHS SHOW MODEST LOOPING. OVERALL...IF INSTABILITY CONDITIONS
ARE MET...ENVISION STORM MODE TO FAVOR RIGHT MOVING CLUSTER OF
CELLS EVOLVING INTO BOWING SEGMENTS WITH THE MAIN THREAT LARGE
HAIL AND DAMAGING WINDS. 0-1 KM SHEAR ENVIRONMENT IS
UNIDIRECTIONAL SO NOT EXPECTING A FAVORABLE TORNADO ENVIRONMENT
HOWEVER WITH THAT SAID...ANY LINGERING SURFACE BOUNDARIES COULD
COMPLICATE THAT.
MODEL AGREEMENT ON FRONTAL TIMING IS HIGHER WITH THE 05.12Z
GUIDANCE...WHICH ADDS CONFIDENCE TO THE LATE AFTERNOON AND EVENING
PRECIPITATION CHANCES. THE NAM REMAINS A FASTER OUTLIER WHILE THE
GEM/GFS/ECMWF ARE CONSISTENT WITH A 00 TO 06Z PASSAGE. EARLIER
FORECAST TIMING FOR POPS LOOK GOOD SO HAVE CARRIED SIMILAR
THINKING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE BIG STORY IN THE LONG TERM WILL BE A CONTINUATION OF THE
UNSEASONABLY COOL WEATHER PATTERN AS THE MAIN POLAR VORTEX / CLOSED
UPPER LOW WOBBLES ACROSS SOUTHERN CANADA. OUTSIDE OF SCATTERED
DAYTIME CUMULUS FIELD ACROSS WISCONSIN WEDNESDAY...HIGH PRESSURE
DOMINATES WITH PLEASANT CONDITIONS. HIGHS LOWER TO MIDDLE 70S.
ANOTHER SIMILAR DAY THURSDAY...THOUGH BY EVENING INTO THE NIGHT THE
CLOSED UPPER LOW WOBBLES FURTHER TO THE SOUTH AS ANOTHER PIECE OF
ENERGY ROUNDS THE BASE. THIS TRIES TO DRIVE A SURFACE COLD FRONT
WITH SHOWERS AND THUNDERSTORMS ACROSS CENTRAL MINNESOTA INTO
WISCONSIN. HOWEVER...BETTER DYNAMICS AND MOISTURE TRANSPORT REMAIN
IN THE WEST AND NORTH FORECAST...AND THE FRONT WASHES OUT BEFORE
MAKING IT VERY FAR INTO THE FORECAST AREA. WILL CONTINUE SLIGHT
CHANCES IN THE NORTHWEST WHILE THE REST OF THE AREA WILL LIKELY ONLY
SEE INCREASED CLOUD COVER.
IN THE WAKE OF THIS SHORTWAVE TROUGH...A REINFORCING SHOT OF COOLER
AIR SURGES IN AS SEEN BY 850 MB TEMPERATURES FRIDAY AND SATURDAY
DROPPING TO THE 8 TO 10C RANGE. HIGHS IN THE 70S AND OVERNIGHT LOWS
COULD DIP INTO THE UPPER 40S TO LOWER 50S...ESPECIALLY FOR THE
TYPICAL COOLER SPOTS OF CENTRAL WISCONSIN. DEPENDING ON THE HIGH
PRESSURE AXIS...COULD SEE A FEW MORNINGS OF RIVER VALLEY FOG AS
WELL. OVERALL...VERY NICE CONDITIONS FOR EARLY/MID AUGUST POSSIBLE
ACROSS THE ENTIRE UPPER MIDWEST FROM FRIDAY INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1124 PM CDT MON AUG 5 2013
CONDITIONS CONTINUE TO DETERIORATE ACROSS THE REGION AS A LOW END
MVFR TO IFR STRATUS DECK STALLED ALONG AND EAST OF THE MISSISSIPPI
RIVER. FURTHER WEST OF THIS STRATUS IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA...SKIES HAVE CLEARED WITH FOG FORMING DUE TO THE
LIGHT WINDS AND RECENT RAINS. EXPECT THAT CONDITIONS WILL CONTINUE
TO DROP THROUGH THE NIGHT WITH VISIBILITY DROPPING TO A QUARTER OF
A MILE AT TIMES...THOUGH LSE HAS BEEN AT 10SM ALL EVENING DESPITE
HAVING A 1KFT DECK OVERHEAD. WARMER AIR WILL MOVE IN TOMORROW
MORNING AND WILL HELP TO IMPROVE CONDITIONS RATHER QUICKLY.
SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP AHEAD OF A
COLD FRONT TUESDAY AFTERNOON/EVENING ACROSS MINNESOTA. SOME BRIEF
DROPS TO IFR WILL BE POSSIBLE AS THESE STORMS ROLL THROUGH
SOMETIME IN THE LATE AFTERNOON AND EARLY EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ086-087-
094-095.
IA...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR IAZ008>010-
018-019-029.
&&
$$
UPDATE.......RIECK
SHORT TERM...ZT
LONG TERM....ZT
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1124 PM CDT MON AUG 5 2013
.UPDATE...
ISSUED AT 912 PM CDT MON AUG 5 2013
DIURNAL CONVECTION HAS GENERALLY COME TO AN END ACROSS THE REGION
WITH SOME TRAILING SHOWERS LINGERING IN SOUTHWEST WISCONSIN ALONG
A WEAK SURFACE TROUGH/COLD FRONT. MID LEVEL SUBSIDENCE NOTED ON
WATER VAPOR HAS ALLOWED FOR SKIES TO CLEAR OUT ACROSS MUCH OF
MINNESOTA AND IOWA. IT WAS LOOKING LIKE WISCONSIN WOULD GET IN ON
THE CLEARING AS WELL...BUT A LOW LEVEL STRATUS DECK GOT STUCK
UNDER A SHALLOW INVERSION AROUND 1500FT AND HAS STALLED OUT FROM
FAR EASTERN MINNESOTA/IOWA ON INTO WESTERN WISCONSIN. WITH THE LOW
LEVEL SURGE OF DRIER AIR APPEARING TO HAVE STALLED OUT TO THE
WEST...AM BECOMING MORE CONCERNED FOR THE POTENTIAL OF DENSE FOG
TONIGHT. THE MAIN UNCERTAINTY IS WITH WHETHER THIS WILL JUST STAY
AS A LOW LEVEL STRATUS DECK BECAUSE OF SOME
STRONGER...10KT...WINDS AT THE INVERSION LEVEL OR IF THE
SATURATION WILL JUST CONTINUE ON DOWN TO THE GROUND OVERNIGHT.
SOME REPORTS FROM NORTHEAST IOWA HAVE BEEN THAT VISIBILITY HAS
DROPPED DOWN TO AN EIGHTH OF A MILE IN SPOTS IN EASTERN FILLMORE
COUNTY AND NORTHERN WINNESHIEK COUNTIES. WITH SUCH HIGH MOISTURE
ALREADY IN PLACE...AM LEANING MORE ALONG THE FOG SOLUTION RATHER
THAN JUST STRATUS. IF QUARTER MILE VISIBILITIES BECOME MORE
WIDESPREAD...MAY HAVE TO DO A DENSE FOG ADVISORY OVERNIGHT.
ALSO...DESPITE LOW LEVEL FORCING LOOKING WEAK...ALSO CAN NOT RULE
OUT SOME DRIZZLE WITH THESE LOW CEILINGS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE NEXT 24 TO 36 HOURS WILL FEATURE A MORE ACTIVE PERIOD WITH A
FEW WEATHER SYSTEMS TO CONTEND WITH INCLUDING PRECIPITATION
CHANCES THIS EVENING...FOG OVERNIGHT...AND THEN SEVERE THREAT
TUESDAY AFTERNOON/EVENING.
LATEST WATER VAPOR COMBINED WITH RAP 500MB HEIGHTS SHOW BROAD
NORTHWEST FLOW EAST OF THE ROCKIES...WITH NUMEROUS EMBEDDED
SHORTWAVE TROUGHS. ONE CURRENTLY MOVING THROUGH
MINNESOTA/IOWA...WHILE UPSTREAM ACROSS ALBERTA SITS A MORE VIGOROUS
WAVE. FINALLY...A CLOSED POLAR VORTEX RESIDES NEAR HUDSON BAY.
FOR THIS EVENING INTO TONIGHT...WILL CARRY A SLIGHT CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS UNTIL UPPER LEVEL SHORTWAVE
COMPLETELY EXITS THE AREA. DESPITE SURFACE TROUGH LAGGING
BEHIND...AND BUILDING INSTABILITY WITH CLEARING SKIES...SUBSIDENCE
IN THE WAKE OF THE UPPER LEVEL SHORTWAVE AND SOME LOW TO MID LEVEL
DRYING SHOULD PRECLUDE THE DEVELOPMENT OF ADDITIONAL SHOWERS/STORMS.
HAVE ADDED PATCHY TO AREAS OF FOG FOR PARTS OF WISCONSIN...INCLUDING
THE MS AND WISCONSIN RIVER VALLEYS OVERNIGHT AS A WEAK SURFACE
HIGH BUILDS IN THE WAKE OF THE DEPARTING SYSTEM AND AHEAD OF THE
APPROACHING COLD FRONT. NICE SETUP WITH TODAY/S COOL...CLOUDY
CONDITIONS AND RECENT RAINFALL...THEN CLEARING SKIES LATE THIS
EVENING. SURFACE WIND FIELD DROPS TO 5 KTS OR LESS...AND SOUNDINGS
SHOW DECENT BOUNDARY LAYER SATURATION THOUGH TRY TO SHOW A STIFF
BREEZE AT ABOUT 500 FT. COULD BE A MORE WIDESPREAD FOG SCENARIO
INSTEAD OF JUST THE RIVER VALLEYS...SOMETHING TO WATCH THIS
EVENING.
THE ALBERTA SHORTWAVE TROUGH THEN TAKES AIM ON THE AREA...AND WILL
BE THE FOCUS FOR PUSHING THROUGH A SURFACE COLD FRONT TUESDAY
EVENING. BUILDING INSTABILITY DURING THE DAY IS SOMEWHAT CONDITIONAL
ON AN EARLY MORNING MCS EXPECTED WELL TO OUR WEST...BUT BY MID
AFTERNOON...MUCAPE BETWEEN 1500 AND 2000 J/KG COULD BE REALIZED. THE
SHEAR ENVIRONMENT IS MORE THAN SUFFICIENT FOR SEVERE STORMS AS 250
MB JET MAX OVERHEAD PUTS 40 TO 50 KTS OF EFFECTIVE SHEAR ACROSS MUCH
OF THE AREA...AND THE LOW-LEVELS HAVE FAVORABLE LAPSE RATES.
HODOGRAPHS SHOW MODEST LOOPING. OVERALL...IF INSTABILITY CONDITIONS
ARE MET...ENVISION STORM MODE TO FAVOR RIGHT MOVING CLUSTER OF
CELLS EVOLVING INTO BOWING SEGMENTS WITH THE MAIN THREAT LARGE
HAIL AND DAMAGING WINDS. 0-1 KM SHEAR ENVIRONMENT IS
UNIDIRECTIONAL SO NOT EXPECTING A FAVORABLE TORNADO ENVIRONMENT
HOWEVER WITH THAT SAID...ANY LINGERING SURFACE BOUNDARIES COULD
COMPLICATE THAT.
MODEL AGREEMENT ON FRONTAL TIMING IS HIGHER WITH THE 05.12Z
GUIDANCE...WHICH ADDS CONFIDENCE TO THE LATE AFTERNOON AND EVENING
PRECIPITATION CHANCES. THE NAM REMAINS A FASTER OUTLIER WHILE THE
GEM/GFS/ECMWF ARE CONSISTENT WITH A 00 TO 06Z PASSAGE. EARLIER
FORECAST TIMING FOR POPS LOOK GOOD SO HAVE CARRIED SIMILAR
THINKING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 310 PM CDT MON AUG 5 2013
THE BIG STORY IN THE LONG TERM WILL BE A CONTINUATION OF THE
UNSEASONABLY COOL WEATHER PATTERN AS THE MAIN POLAR VORTEX / CLOSED
UPPER LOW WOBBLES ACROSS SOUTHERN CANADA. OUTSIDE OF SCATTERED
DAYTIME CUMULUS FIELD ACROSS WISCONSIN WEDNESDAY...HIGH PRESSURE
DOMINATES WITH PLEASANT CONDITIONS. HIGHS LOWER TO MIDDLE 70S.
ANOTHER SIMILAR DAY THURSDAY...THOUGH BY EVENING INTO THE NIGHT THE
CLOSED UPPER LOW WOBBLES FURTHER TO THE SOUTH AS ANOTHER PIECE OF
ENERGY ROUNDS THE BASE. THIS TRIES TO DRIVE A SURFACE COLD FRONT
WITH SHOWERS AND THUNDERSTORMS ACROSS CENTRAL MINNESOTA INTO
WISCONSIN. HOWEVER...BETTER DYNAMICS AND MOISTURE TRANSPORT REMAIN
IN THE WEST AND NORTH FORECAST...AND THE FRONT WASHES OUT BEFORE
MAKING IT VERY FAR INTO THE FORECAST AREA. WILL CONTINUE SLIGHT
CHANCES IN THE NORTHWEST WHILE THE REST OF THE AREA WILL LIKELY ONLY
SEE INCREASED CLOUD COVER.
IN THE WAKE OF THIS SHORTWAVE TROUGH...A REINFORCING SHOT OF COOLER
AIR SURGES IN AS SEEN BY 850 MB TEMPERATURES FRIDAY AND SATURDAY
DROPPING TO THE 8 TO 10C RANGE. HIGHS IN THE 70S AND OVERNIGHT LOWS
COULD DIP INTO THE UPPER 40S TO LOWER 50S...ESPECIALLY FOR THE
TYPICAL COOLER SPOTS OF CENTRAL WISCONSIN. DEPENDING ON THE HIGH
PRESSURE AXIS...COULD SEE A FEW MORNINGS OF RIVER VALLEY FOG AS
WELL. OVERALL...VERY NICE CONDITIONS FOR EARLY/MID AUGUST POSSIBLE
ACROSS THE ENTIRE UPPER MIDWEST FROM FRIDAY INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1124 PM CDT MON AUG 5 2013
CONDITIONS CONTINUE TO DETERIORATE ACROSS THE REGION AS A LOW END
MVFR TO IFR STRATUS DECK STALLED ALONG AND EAST OF THE MISSISSIPPI
RIVER. FURTHER WEST OF THIS STRATUS IN SOUTHEAST MINNESOTA AND
NORTHEAST IOWA...SKIES HAVE CLEARED WITH FOG FORMING DUE TO THE
LIGHT WINDS AND RECENT RAINS. EXPECT THAT CONDITIONS WILL CONTINUE
TO DROP THROUGH THE NIGHT WITH VISIBILITY DROPPING TO A QUARTER OF
A MILE AT TIMES...THOUGH LSE HAS BEEN AT 10SM ALL EVENING DESPITE
HAVING A 1KFT DECK OVERHEAD. WARMER AIR WILL MOVE IN TOMORROW
MORNING AND WILL HELP TO IMPROVE CONDITIONS RATHER QUICKLY.
SHOWERS AND THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP AHEAD OF A
COLD FRONT TUESDAY AFTERNOON/EVENING ACROSS MINNESOTA. SOME BRIEF
DROPS TO IFR WILL BE POSSIBLE AS THESE STORMS ROLL THROUGH
SOMETIME IN THE LATE AFTERNOON AND EARLY EVENING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...ZT
LONG TERM....ZT
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
521 PM MDT WED AUG 7 2013
.UPDATE...
ISSUED AT 518 PM MDT WED AUG 7 2013
UPDATED FORECAST FOR THIS EVENING TO INCLUDE THE SEVERE
THUNDERSTORM WATCH FOR CONVERSE...NIOBRARA COUNTIES IN ADDITION TO
THE NORTHERN NEBRASKA PANHANDLE. THIS WATCH IS IN EFFECT UNTIL 11
PM TONIGHT FOR THE THREAT OF LARGE HAIL AND DAMAGING WINDS. SEVERE
THUNDERSTORMS SHOULD BE RATHER ISOLATED IN NATURE THROUGH THIS
EVENING.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 300 PM MDT WED AUG 7 2013
SHOWERS AND THUNDERSTORMS WERE DEVELOPING EARLY THIS AFTERNOON
OVER VARIOUS PARTS OF THE CWA. THE ACTIVITY IS SLOWLY BECOMING
MORE INTENSE...BUT SO FAR HAS BEEN HINDERED SOME BY THE CIRRUS
CURRENTLY OVER THE AREA. AT LEAST A SCATTERED COVERAGE OF STORMS
SHOULD CONTINUE THROUGH EARLY THURSDAY MORNING. THE ATMOSPHERE
IS MOIST AND UNSTABLE WITH SURFACE FORCING NEAR THE MOUNTAINS.
IN ADDITION...A SHORTWAVE TROUGH NEAR THE FOUR CORNERS REGION
EARLY THIS AFTERNOON WILL MOVE NORTHEAST AND NEAR THE CWA
THROUGH EARLY THURSDAY MORNING. THE MAIN THREAT STILL APPEARS
TO BE A PERIOD OF HEAVY RAIN...SMALL HAIL AND GUSTY WINDS
THROUGH THE EVENING. THE BEST POTENTIAL FOR SEVERE STORMS WILL
BE IN THE NORTH PART OF THE CWA IN THE AREA OF BETTER 0-6 KM
SHEAR THROUGH THIS EVENING. AREAS OF LOW CLOUDS AND FOG WILL
BE POSSIBLE LATER TONIGHT AND INTO MID MORNING THURSDAY FROM
KSNY TO THE SOUTHERN LARAMIE RANGE.
BY MIDDAY THURSDAY...HEIGHTS ALOFT BUILD OVER THE ROCKIES WITH
A SHORTWAVE RIDGE OVER THE AREA THROUGH FRIDAY. THE PLUME OF
MID AND UPPER LEVEL MOISTURE WILL BE MAINLY OVER THE SOUTH PART
OF THE CWA THURSDAY AND THEN OVER THE ENTIRE CWA FRIDAY. MOIST
BOUNDARY LAYER UPSLOPE WINDS WILL CONTINUE THROUGH FRIDAY WITH
SURFACE DEW POINTS IN THE 50S TO THE EAST OF THE LARAMIE RANGE.
PRECIPITABLE WATER VALUES THROUGH THAT TIME WILL CONTINUE TO
RANGE FROM NEAR ONE HALF INCH OVER SOUTH CENTRAL WYOMING TO
AN INCH OVER THE PANHANDLE. A SCATTERED COVERAGE OF AFTERNOON
AND EVENING THUNDERSTORMS WILL AGAIN TAKE PLACE OVER THE CWA ON
THURSDAY. THEN ON FRIDAY...MODELS MOVE A MORE SIGNIFICANT
SHORTWAVE NEAR THE CWA. THAT SHOULD RESULT IN MORE COVERAGE AND
PERHAPS HEAVIER RAINFALL. TEMPERATURES WILL BE SIMILAR OVER
THE CWA THROUGH FRIDAY WITH READINGS NEAR OR JUST BELOW NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 PM MDT WED AUG 7 2013
NEW ECMWF 12Z RUN CONTINUES TO BE MORE BULLISH ON QPF...PARTICULARLY
WEST OF THE LARAMIE RANGE FRIDAY NIGHT. NAM/WRF BACKS THE ECMWF
SOLUTIONS...SO KEPT PRETTY HIGH POPS GOING OUT WEST FRIDAY NIGHT.
THIS IS DUE TO A PRETTY POTENT VORT MAX TRACKING NORTHEAST THROUGH
THE RIDGE. ITS REALLY SLOW MOVING TO THE NORTHEAST AND BY SATURDAY
MORNING...IT FINALLY CLEARS TO CWFA. SO CURRENTLY THINKING IS FOR
SHOWERS AND THUNDERSTORMS TO CONTINUE ALL NIGHT...PARTICULARLY OUT
WEST AND INTO CONVERSE COUNTY.
RESIDUAL MOISTURE AND UPSLOPING WINDS EAST OF THE LARAMIE RANGE
WILL AID IN ANOTHER ROUND OF AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS SATURDAY AND SATURDAY EVENING.
WE ARE LOOKING AT THE BROKEN RECORD CONTINUING THROUGH MID WEEK AS
MONSOONAL MOISTURE REMAINS OVER THE AREA. ITS A GOOD PROBLEM TO
HAVE AS WE ARE STILL WAY BELOW ON RAINFALL...AND THE RAIN KEEPS
FIRE WEATHER CONCERNS AT BAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1046 AM MDT WED AUG 7 2013
LOOKS LIKE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS FOR THIS
AFTERNOON. LATEST HRRR FORECAST SHOWING THUNDERSTORMS FORMING
ALONG A LINE JUST NORTH OF CHADRON OVER TO LUSK AROUND
19Z...SWEEPING SOUTH THROUGH THE SOUTHERN PANHANDLE BY
00Z. BASED TIMING ON ITS FORECAST. THEN BEHIND THE LINE...WE SEE A
NORTHEAST WIND DEVELOPING BEHIND THIS LINE. HRRR AND SREF SHOWING
A FAIRLY WIDESPREAD AND PROLONGED LOW CEILING EVENT WITH THESE
NORTHEAST UPSLOPING WINDS. BELIEVE THE MOST PROBABLE AREA WILL BE
HERE AT KCYS AND KSNY IN THE SOUTHERN PANHANDLE. BUT KAIA AND KBFF
COULD ALSO BE IMPACTED. SHOULD THESE AIRPORTS AND THE PANHANDLE
RECEIVE GOOD RAINFALL TODAY...THEN CONFIDENCE WILL CERTAINLY GROW
THAT IT WILL HAPPEN.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT WED AUG 7 2013
MONSOONAL MOISTURE WILL REMAIN OVER THE CWA THROUGH AT LEAST
FRIDAY. THE RESULT WILL BE AT LEAST A SCATTERED COVERAGE OF
MAINLY LATE DAY SHOWERS AND THUNDERSTORMS EACH DAY AND
TEMPERATURES AT OR JUST BELOW NORMAL. THE ATMOSPHERE DRIES
SOME FOR THE WEEKEND AND EARLY NEXT WEEK AND MAY RESULT IN
MARGINAL FIRE WEATHER CONDITIONS FOR THE LOWER ELEVATIONS OF THE
WEST PART OF THE CWA. HOWEVER...WINDS IN MOST AREAS WILL BE
FAIRLY LIGHT THROUGH EARLY NEXT WEEK. IN GENERAL THAT LEADS TO
A REDUCED FIRE WEATHER CONCERN OVER THE CWA DURING THAT TIME.
DRY THUNDERSTORMS WILL BE A POSSIBILITY ON SOME DAYS OVER THE
LOWER ELEVATIONS OF CARBON COUNTY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...TJT
SHORT TERM...WEILAND
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...WEILAND
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1039 PM MDT WED AUG 7 2013
.UPDATE...
ISSUED AT 1039 PM MDT WED AUG 7 2013
UPDATED TO CANCEL THE FLASH FLOOD WATCH. MUCH OF THE PRECIPITATION
OVER SOUTHERN COLORADO AND SOUTHEAST UT HAS DIMINISHED AND THE
THREAT OF FLOODING HAS ENDED.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 320 PM MDT WED AUG 7 2013
COMPLEX WEATHER PATTERN AFFECTING THE REGION THIS AFTERNOON. AT
THE SURFACE THERE IS A WEAK QUASI STATIONARY FRONTAL BOUNDARY
DRAPED NEAR THE WY BORDER. ALOFT AND STUCK IN AN UPPER LEVEL RIDGE
AXIS IS A SHORTWAVE TROUGH CENTERED IN SOUTH CENTRAL UT. WHILE THE
CENTER OF ROTATION WILL STRUGGLE TO MOVE EAST TONIGHT AS EVIDENCED
BY THE RAP MODEL...ITS TROUGH WILL ROTATE NORTHEAST INTO SOUTHERN
CO. AXIS OF GREATEST INSTABILITY...MUCAPES 1000 TO 2000 J/KG...
EXTENDS ALONG THE CO/NM BORDER AT THIS TIME AND THIS INDEED IS
WHERE THE MOST VIGOROUS CONVECTION HAS DEVELOPED. THESE STORMS
WILL MOVE NORTHEAST INTO SOUTHWEST CO AND INTO THE SAN JUAN MTNS
THROUGH EARLY EVENING. MEANWHILE...RAINFALL ASSOCIATED WITH THE
CENTER OF ROTATION ACROSS SRN UT WILL ALSO MOVE EAST. OBSERVED
RAINFALL RATES SO FAR THIS AFTERNOON HAVE BEEN 0.2 TO 0.3/HOUR IN
PARTS OF THE SAN JUANS AND IN THE CENTRAL MTNS. EXPECT EVEN HIGHER
RATES TO OCCUR WITH THE STRONG CONVECTION. SO FLASH FLOOD WATCH
LOOKS GOOD AND WILL REMAIN IN EFFECT THROUGH MIDNIGHT. THERE IS A
MID LEVEL SHEAR AXIS BASICALLY ALONG I-70 WITH DRIER AIR TO THE
NORTH. CONSEQUENTLY CONVECTION NORTH OF I-70 WILL BE LESS ROBUST.
EXPECT SHOWERS TO DIMINISH OVERNIGHT BUT LINGER OVER THE CENTRAL
AND SOUTHERN AREAS TO SOME EXTENT.
ON THURSDAY...THE SHORTWAVE SHOULD BE EAST OF THE AREA WITH THE
RIDGE AXIS AGAIN DOMINATING. HOWEVER...THERE WILL STILL BE MID TO
HIGH LEVEL MOISTURE TRAPPED UNDER THE RIDGE...SO EXPECT ISOLATED
TO SCATTERED CONVECTION DIURNAL CONVECTION WEST TO NUMEROUS STORMS
EAST...FOCUSED ON THE USUAL HIGHER TERRAIN LOCATIONS.
SLIGHTLY LESS CLOUD COVER INITIALLY ON THURSDAY WILL HELP TEMPS
RISE A LITTLE QUICKER AND HIGHER THAN TODAY...THOUGH STILL REMAIN
BELOW NORMAL.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 320 PM MDT WED AUG 7 2013
THE LARGE SCALE PATTERN CHANGES LITTLE AS A LOW PRESSURE TROUGH
CONTINUES TO SIT ALONG THE WEST COAST...AND HIGH PRESSURE REMAINS
PARKED OVER TEXAS. AFTER A BRIEF PERIOD OF NORTH/NORTHWEST FLOW
BEHIND TODAY`S DISTURBANCE...SOUTHERLY FLOW WILL QUICKLY BECOME
REESTABLISHED ON FRIDAY. HOWEVER MODELS CONTINUE TO ADVERTISE A
MODEST DROP IN MOISTURE ACROSS THE AREA. THESE SOMEWHAT DRIER
CONDITIONS WILL THEN PERSIST THROUGH THE EARLY PART OF NEXT WEEK.
PRECIPITABLE WATER WILL DROP FROM TODAY`S VALUES OF 0.6-1.0 INCH
...NORTH-SOUTH/CENTRAL TO MORE LIKE 0.4-0.6 INCH ACROSS MOST OF
THE AREA. THE LATEST MODEL RUNS HAVE DELAYED FURTHER DRYING UNTIL
AROUND MIDWEEK. BETTER SUNSHINE AND THIS MODEST AMOUNT OF MOISTURE
WILL STILL RESULT IN ISOLATED TO SCATTERED AFTERNOON SHOWER AND
THUNDERSTORM DEVELOPMENT...BUT THIS WILL GENERALLY BE TIED TO THE
HIGHER TERRAIN IN THIS DRIER ENVIRONMENT. ONE WEAK DISTURBANCE
WILL PASS ACROSS ID/WY AROUND THE TOP OF THE RIDGE ON FRIDAY FOR A
LITTLE ENHANCEMENT ACROSS THE NORTH...OTHERWISE THE SOUTH WILL BE
FAVORED.
THE 12Z GFS AND ECMWF RUNS SHOW GOOD AGREEMENT WITH THIS
PERSISTENT PATTERN...AND AS THE HIGH EVENTUALLY SHIFTS WEST INTO
SOUTHERN NM/AZ BY THE MIDDLE OF NEXT WEEK. AS THE HIGH REACHES
SOUTHERN NM...IT WILL TEND TO BLOCK THE SUBTROPICAL MOISTURE
STREAM. THEREFORE LOOK FOR ANOTHER NOTCH OF DRYING. IN SPITE OF
GOOD MODEL AGREEMENT...SUBSEQUENT MODEL RUNS HAVE SLOWED THE
DRYING TREND. THEREFORE CONFIDENCE IS NOT OVERLY HIGH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1039 PM MDT WED AUG 7 2013
VFR CONDITIONS WILL PREVAIL AT THE TAFS SITES TONIGHT. AREAS OF
PRECIPITATION OVER SW CO AND SE UT WILL PRODUCE LOCAL MOUNTAIN
OBSCURATIONS. SCATTERED THUNDERSTORMS SHOULD FORM THURSDAY
AFTERNOON AND EVENING...MAINLY OVER THE MOUNTAINS. KASE...KRIL...
AND KEGE HAVE ABOUT AT 15 PERCENT CHANCE OF MVFR VSBYS IN STRONGER
RAIN SHOWERS. THE STORMS WILL CAUSE LOCAL MOUNTAINS OBSCURATIONS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...CC
SHORT TERM...BWM
LONG TERM...EH
AVIATION...CC
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
403 AM CDT Thu Aug 8 2013
...UPDATED LONG TERM SECTION...
.SYNOPSIS...
ISSUED AT 1010 PM CDT WED AUG 7 2013
The 08.00Z 250 hPa showed 50 KT flow extending from KDDC increasing
to around 100 KT at KAPX. @ 500 hPa, a 577-580 decameter cyclone was
spinning off northwest California. Downstream, an open wave was moving
across the central Rockies. A huge 550 decameter cyclone was noted across
west central Ontario. @ 700 hPa, easterly upslope flow was observed
at KDDC. This upslope flow also continued at 850 hPa and down to the
sfc. The precipitable water for KDDC was 1.41" (above the 75th percentile
for a Gaussian distribution). At the sfc, a stationary front was located
across the KS/OK state border. KDDC WSR-88D was busy indicating an
MCS to the west.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 254 AM CDT THU AUG 8 2013
...Pretty busy shift this morning. Most of the attention was paid to
overnight convection and then some to this afternoon...
This morning:
A fairly significant rain event occurred through the overnight period.
Rainfall reports have been pretty sparse given the fact that it is O`Dark
Thirty. We should get more reports by dawn. A few reports have trickled
in with 3.00" in Hugoton, 1.50" by Richfield, and a few flash flooding
reports. Here at the KDDC airport as of 07:24Z, we have had a measly
half of an inch. Southern Ford county and other areas probably saw 2"
to 4" via estimation from radar. Anyway, given the initial event, canceled
the Flood Watch and issued a Flash Flood Watch instead. So, why all
the precip? Well, an upper level wave, 850 hPa theta-e advection, pwats
around the 75th percentile, sfc-700 hPa upslope flow, and isentropic
lift was the impetus for MCS formation. For the rest of the early morning,
will taper precipitation probability percentage points west to east
via radar trends and HRRR guidance. FWIW, the 00Z NAM performed poorly
for the event.
Will carry the FF.A (Flash Flood Watch) until 18Z.
Today/tonight:
We should see some break in the precipitation from the morning activity
to possible additional activity later this afternoon as temporary subsidence
builds in the wake of the departing MCS. Forecast skew-t/log-p`s show
pwats still in the 1.50-1.70" range this afternoon. A moist upslope
flow will also continue from the sfc up through 800 hPa. The main synoptic
wave mentioned in the synopsis will have translated over western Kansas by
afternoon, and this will provide some upper level support for additional
lift. The atmosphere will become unstable again with 1000-2000 J/kg
of SBCAPE. Low to mid level lapse rates are fairly moist adiabatic,
so the CAPE profile is fairly skinny. Bulk shear vectors are SW/40 KT.
All and all, tomorrow does not look that impressive for severe weather
(supercells etc). What does look more promising is another MCS. There
is significant questions in regarding convective initiation/placement.
The ECMWF and both cores of the WRF look reasonable. The atmosphere
could be "worked over" from the morning convection, so a lack of additional
activity is also possible. Anywho, will carry chance precipitation probabilities
this afternoon and ramp them up to likely region wide by tonight. Maximums
will be in the 70sF and minimums in the 60sF.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 353 AM CDT THU AUG 8 2013
A shortwave trough will move across the central plains reaching
the lower Missouri River Valley by late Friday with shortwave
ridging moving into the western plains. This will provide a break
in precipitation chances from late Friday into Saturday night with
surface ridging across Kansas. Low level moisture will still be
around, however, given all the saturated ground providing ample
evapotranspiration...so dewpoint temperatures will remain int he
60s for the most part despite there being some mid level
subsidence. Some subtropical jet energy will begin to move into
the desert Southwest region impinging on the southern Rockies by
Sunday night into early next week...and this is when precipitation
chances will once again be on the increase. As far as the grids
go...no changes were made to the forecast and the latest all-blend
guidance was used for the Sunday-Thursday time frame.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1212 AM CDT THU AUG 8 2013
MVFR cigs expected through the overnight with VFR cigs after 15Z
or so. NE-E 8-11 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 75 63 78 61 / 60 70 20 10
GCK 74 61 77 57 / 60 70 20 10
EHA 77 62 80 60 / 60 70 10 10
LBL 79 63 80 61 / 60 70 20 10
HYS 74 62 76 61 / 100 70 30 10
P28 80 67 81 65 / 100 80 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH until 1 PM CDT /Noon MDT/ this afternoon FOR
KSZ030-031-043>046-061>066-074>081-084>090.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Sugden
LONG TERM...UMSCHEID
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS WICHITA KS
328 AM CDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
TODAY & TONIGHT:
AS ALL OBVIOUSLY KNOW...FLOODING TO CONTINUE BEINGING THE HIGHLIGHT OF
FOR PERIODS AS FLOOD WATCH REMAINS IN EFFECT TIL 7 AM FRIDAY.
DURING THE NIGHT A POORLY-DEFINED STATIONARY FRONT WAS DRAPED IN AN E-W
MANNER GENERALLY THROUGH CNTRL OK WITH A WEAK 700-MB TROF SITUATED FROM
THE UT/CO BORDER TO ~CA/AZ BORDER. WITH THE TROF SLOWLY EVOLVING INTO A
WEAK LOW AS IT VENTURES E TO WRN KS RICH & DEEP MOISTURE WILL CONTINUE
TO SPREAD NE ACROSS KS. WITH THE MID-LVL "KICKER" LACKING THE SFC-850MB
FRONTS WILL MOVE VERY LITTLE...IF AT ALL...THEREBY PROMOTING BROAD ECHO
TRAINING OVER KICT COUNTRY WHICH IN TURN WOULD EXACERBATE THE FLOODING
SITUATION ACROSS THE CWA. ONLY CHANGES TO INHERITED FORECAST WERE TO
SHIFT THE POP GRADIENT TO GENERALLY A N/S ORIENTATION TO BETTER ALIGN
WITH THE BROAD LWR-MID DECK MOISTURE CHANNEL. ASSIGNED 80-100% TO CNTRL
& SC KS THIS MORNING WITH HIGHEST POPS & ASSOCIATED TSRA SHIFTED E OVER
SE KS THIS AFTERNOON AS HRRR DEPICTS. PW`S REMAIN IN 175-200% RANGE SO
CONTINUED TO HIT QPFS HARD.
FRI & FRI NIGHT:
A FAIRLY BROAD UPR-DECK RIDGE IS FORECAST MOVE SLOWLY MOVG E TOWARD THE
CNTRL ROCKIES...THE WEAK MID-LVL LOW WILL GET FORCED E TOWARD...THEN
ACROSS...ERN KS. THIS WOULD THEREFORE SHIFT BULK OF +TSRA E ACROSS THE
KS/MO BORDER ON FRI WITH -TSRA CONFINED FROM GENERALLY THE FLINT HILLS
E FRI NGT. AS SUCH WILL CONTINUE TO SCHEDULE THE FLOOD WATCH TO END AT
7AM FRI.
SAT & SAT NGT:
MOST AREAS WILL EXPERIENCE AN INTERMISSION FROM TSRA. A FEW TSRA SHOULD
VENTURE TOWARD THE WRN CORRIDOR SAT NGT AS WEAK LWR-DECK TROFFING
BEGINS ALONG THE FRONT RANGE.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
ALL AREAS TO BE UNDER A WEAK NW FLOW REGIME FOR MOST OF THESE PERIODS.
A WEAK COLD FRONT WILL VENTURE SE TOWARD & PERHAPS ACROSS KICGT COUNTRY
EARLY NEXT WEEK WHICH WOULD INCREASE TSRA CHANCES FOR MUCH OF THESE
PERIODS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1137 PM CDT WED AUG 7 2013
MAIN MCS STRETCHING FROM WESTERN KS INTO WESTERN OK WILL TRACK
EASTWARD ACROSS CENTRAL/SOUTH CENTRAL/SOUTHEAST KS LATE TONIGHT
INTO THE EARLY MORNING HOURS THURSDAY. STRONGEST ACTIVITY COULD
PRODUCE SOME GUSTY WINDS/HEAVY RAIN AT HUT AND ICT FROM 08-12Z.
SHOWERS/STORMS COULD REDEVELOP AND BECOME FAIRLY WIDESPREAD LATER
THURSDAY AFTERNOON INTO THURSDAY NIGHT WITH SOME VSBY/CIG
REDUCTIONS INTO AT LEAST THE MVFR RANGE AT TIMES.
JMC
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 80 68 79 65 / 100 90 40 10
HUTCHINSON 78 65 76 63 / 100 90 40 10
NEWTON 78 66 76 63 / 100 90 50 10
ELDORADO 79 67 79 64 / 100 90 50 20
WINFIELD-KWLD 82 70 82 66 / 100 70 30 10
RUSSELL 77 63 76 62 / 100 70 40 10
GREAT BEND 77 63 75 61 / 100 80 40 10
SALINA 78 65 77 63 / 100 80 50 10
MCPHERSON 78 65 76 63 / 100 80 50 10
COFFEYVILLE 85 71 86 68 / 80 80 40 20
CHANUTE 81 69 81 66 / 80 80 60 20
IOLA 80 68 80 66 / 80 80 70 20
PARSONS-KPPF 83 70 84 67 / 80 80 50 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY MORNING FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
ES
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
254 AM CDT Thu Aug 8 2013
...Update to short term discussion...
.SYNOPSIS...
ISSUED AT 1010 PM CDT WED AUG 7 2013
The 08.00Z 250 hPa showed 50 KT flow extending from KDDC increasing
to around 100 KT at KAPX. @ 500 hPa, a 577-580 decameter cyclone was
spinning off northwest California. Downstream, an open wave was moving
across the central Rockies. A huge 550 decameter cyclone was noted across
west central Ontario. @ 700 hPa, easterly upslope flow was observed
at KDDC. This upslope flow also continued at 850 hPa and down to the
sfc. The precipitable water for KDDC was 1.41" (above the 75th percentile
for a Gaussian distribution). At the sfc, a stationary front was located
across the KS/OK state border. KDDC WSR-88D was busy indicating an
MCS to the west.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 254 AM CDT THU AUG 8 2013
...Pretty busy shift this morning. Most of the attention was paid to
overnight convection and then some to this afternoon...
This morning:
A fairly significant rain event occurred through the overnight period.
Rainfall reports have been pretty sparse given the fact that it is O`Dark
Thirty. We should get more reports by dawn. A few reports have trickled
in with 3.00" in Hugoton, 1.50" by Richfield, and a few flash flooding
reports. Here at the KDDC airport as of 07:24Z, we have had a measly
half of an inch. Southern Ford county and other areas probably saw 2"
to 4" via estimation from radar. Anyway, given the initial event, canceled
the Flood Watch and issued a Flash Flood Watch instead. So, why all
the precip? Well, an upper level wave, 850 hPa theta-e advection, pwats
around the 75th percentile, sfc-700 hPa upslope flow, and isentropic
lift was the impetus for MCS formation. For the rest of the early morning,
will taper precipitation probability percentage points west to east
via radar trends and HRRR guidance. FWIW, the 00Z NAM performed poorly
for the event.
Will carry the FF.A (Flash Flood Watch) until 18Z.
Today/tonight:
We should see some break in the precipitation from the morning activity
to possible additional activity later this afternoon as temporary subsidence
builds in the wake of the departing MCS. Forecast skew-t/log-p`s show
pwats still in the 1.50-1.70" range this afternoon. A moist upslope
flow will also continue from the sfc up through 800 hPa. The main synoptic
wave mentioned in the synopsis will have translated over western Kansas by
afternoon, and this will provide some upper level support for additional
lift. The atmosphere will become unstable again with 1000-2000 J/kg
of SBCAPE. Low to mid level lapse rates are fairly moist adiabatic,
so the CAPE profile is fairly skinny. Bulk shear vectors are SW/40 KT.
All and all, tomorrow does not look that impressive for severe weather
(supercells etc). What does look more promising is another MCS. There
is significant questions in regarding convective initiation/placement.
The ECMWF and both cores of the WRF look reasonable. The atmosphere
could be "worked over" from the morning convection, so a lack of additional
activity is also possible. Anywho, will carry chance precipitation probabilities
this afternoon and ramp them up to likely region wide by tonight. Maximums
will be in the 70sF and minimums in the 60sF.
.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 228 PM CDT WED AUG 7 2013
Medium range models indicate little change to the overall large
scale pattern through early next week with a low amplitude upper
level ridge remaining in place across the central and southern
Rockies. Early in the period, a significant upper level shortwave
is expected to eject out of the southern Rockies east-northeast
into the western high plains bringing the possibility for more
showers and thunderstorms to portions of western Kansas Thursday
night into early Friday. As the shortwave approaches, a prevailing
surface low across the Texas panhandle and an attendant frontal
boundary extending generally east across northern Oklahoma, will
provide increased lift within a low level convergence zone generally
along and just north of the Kansas border. Although the flow aloft
will remain fairly weak, a few showers and isolated thunderstorms
will be possible across much of southwest and central Kansas with
enough instability present as surface dewpoints remain well up into
the 60s(F).
A brief break in precip chances is expected generally Friday night
into Saturday as surface high pressure migrates southward into
western Kansas pushing a frontal boundary just to our south further
down into west Texas and southern Oklahoma. Chances for
thunderstorms will return to portions of western Kansas Sunday as
the weak upper level ridge begins to build across the Rockies
returning a westerly flow aloft to the western high plains. In
response, the frontal boundary well to our south is expected to
return northward providing the focus for thunderstorm development
across the region into early next week.
Below normal temperatures are likely Friday as the aforementioned
surface low in the Texas panhandle pushes off to the east setting up
a more north to northeasterly low level flow across western Kansas.
Slightly cooler air will filter down into western Kansas with H85
temperatures ranging from the mid teens(C) across central Kansas to
near 20C in far southwest Kansas. Along with increased clouds, look
for highs only up into the 70s(F) to possibly near 80F across much
of central and southwest Kansas Friday afternoon. A gradual warming
trend is then expected through the weekend as the upper level
ridging in the intermountain west begins to amplify. Highs back up
into the 80s(F) to near 90F are likely over the weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 1212 AM CDT THU AUG 8 2013
MVFR cigs expected through the overnight with VFR cigs after 15Z
or so. NE-E 8-11 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 75 63 78 61 / 60 70 20 10
GCK 74 61 77 57 / 60 70 20 10
EHA 77 62 80 60 / 60 70 10 10
LBL 79 63 80 61 / 60 70 20 10
HYS 74 62 76 61 / 100 70 30 10
P28 80 67 81 65 / 100 80 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH until 1 PM CDT /Noon MDT/ this afternoon FOR
KSZ030-031-043>046-061>066-074>081-084>090.
&&
$$
SYNOPSIS...Sugden
SHORT TERM...Sugden
LONG TERM...JJOHNSON
AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1114 PM MDT WED AUG 7 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 221 PM MDT WED AUG 7 2013
LATEST WV IMAGERY AND RAP H5 ANALYSIS INDICATES ZONAL FLOW STILL IN
PLACE ACROSS THE CONUS WITH STRONG CLOSED LOW OVER CENTRAL CANADA.
AN EMBEDDED H5/H7 LOW IN IN PLACE UPSTREAM OF THE CWA OVER THE FOUR
CORNER REGION.
LARGE SCALE FORCING AND MID LEVEL MOISTURE CONTINUE TO ADVECT INTO
THE CWA FROM THE SOUTHWEST AHEAD OF THE FOUR CORNERS TROUGH. RAP
ANALYSIS STILL SHOWS 500-1500 J/KG OF MUCAPE IN PLACE...SO
THUNDERSTORMS ARE CERTAINLY POSSIBLE. AT THIS POINT OVERALL THREAT
FOR SEVERE THUNDERSTORMS SEEMS LOW. MODELS CONTINUE TO PAIN BULLS EYE
OF 0.50+ QPF...FAVORING SOUTHERN LOCATIONS. AT THE SAME
TIME...NAM/SREF HAVE TRENDED FURTHER NORTH WHICH DOES SEEM TO HAVE
SUPPORT LOOKING AT LATEST RADAR TRENDS. I ADJUSTED POPS ACCORDINGLY.
RAP INDICATES PWATS IN EXCESS OF 1.3"...AND WHILE LOWER THAN THE LAST
FEW DAYS IS STILL CLIMATOLOGICALLY HIGH. BASED ON RADAR/SATELLITE
TRENDS...AND THE NATURE OF THIS PATTERN...I AM CURRENTLY EXPECTING
SEVERAL PERIODS OF SHOWERS/THUNDERSTORMS ROTATING ACROSS OUR CWA
THROUGH TONIGHT...BEFORE THE MAIN TROUGH MOVES ACROSS THE REGION. AS
THIS OCCURS WE MIGHT SEE OUR BEST CHANCE FOR HEAVY PRECIP ACROSS
MOST OF THE CWA. THERE IS STILL SOME INDICATION THIS COULD OCCUR
LATER IN THE DAY THURSDAY...HOWEVER CONSENSUS SUPPORTS A MORNING
TROUGH PASSAGE AND DECREASING CHANCES THROUGH MIDDAY THURSDAY.
REGARDING WATCH...CONSIDERING THE LIKELIHOOD THAT PRECIPITATION WILL
REMAIN LIGHT TO MODERATE ACROSS MOST OF THE AREA WITH HIGHEST
TOTALS SPREAD OUT OVER 6-12HR PERIOD...I AM STARTING TO QUESTION
THE POTENTIAL FOR FLASH FLOODING. LATEST 6HR FLASH FLOOD GUIDANCE IS
GENERALLY IN THE 2-3 INCH RANGE OVER THE WATCH AREA AND UNLESS WE CAN
GET A STRONG THUNDERSTORM EMBEDDED WITHIN THE LARGER AREA OF
LIGHT-MODERATE RAIN IM NOT SURE WE WILL SEE THESE RATES. WE MAY BE
ABLE TO CANCEL THE WATCH LATER THIS EVENING...BUT I WOULD RATHER
WAIT AND SEE HOW CONVECTION EVOLVES.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 221 PM MDT WED AUG 7 2013
THURSDAY EVENING THE UPPER LEVEL SHORT WAVE TROUGH WILL MOVE EAST OF
THE AREA. WITH THE NOSE OF THE LOW LEVEL JET OVER THE EASTERN PART
OF THE AREA AS WELL...AND A WEAK RIGHT ENTRANCE REGION OF THE 300MB
JET OVER THE AREA...THERE MAY BE SOME LINGERING PRECIP. ACTIVITY
AHEAD OF THE EXITING TROUGH. MEANWHILE BEHIND THE TROUGH DRIER AIR
WILL BE MOVING IN WHICH WILL CAUSE PRECIP. CHANCES TO DECLINE FROM
WEST TO EAST. HOWEVER WITH COOLER AIR MOVING IN THERE WILL BE SOME
INSTABILITY LINGERING BEHIND THE TROUGH. WITH SOME MUCH SMALLER
UPPER LEVEL DISTURBANCES MOVING THROUGH BEHIND THE MAIN
FEATURE...ISOLATED STORMS CANNOT BE RULED OUT DURING THE EVENING AND
INTO THE OVERNIGHT HOURS.
FRIDAY ANOTHER UPPER LEVEL SHORT WAVE TROUGH WILL DEVELOP OVER FAR
EASTERN COLORADO IN THE LATE AFTERNOON. AT THE SURFACE A TROUGH
WILL BE OVER THE WESTERN BORDER OF THE TRI-STATE AREA BENEATH THE
SHORT WAVE. WITH SURFACE CONVERGENCE AND UPPER LEVEL
LIFT...ANTICIPATE SOME STORMS DEVELOPING ALONG THE SURFACE TROUGH
DURING THE MID AFTERNOON INTO THE EARLY EVENING. MEAN STORM
MOTIONS WILL BE VERY SLOW...WITH MOTIONS TURNING FROM THE WEST TO
THE NORTH. THESE MOTIONS WILL KEEP THE STORMS CONFINED TO THE
SURFACE TROUGH. BY THE LATE EVENING ANY STORMS THAT DEVELOPED WILL
DISSIPATE AS THE ENVIRONMENT STABILIZES. THE MAIN THREAT WITH ANY
STORMS THAT DEVELOP WILL BE HEAVY RAINFALL.
SATURDAY THROUGH WEDNESDAY THE UPPER LEVEL RIDGE OVER THE SOUTHWEST
CONUS WILL SLOWLY BUILD NORTHWARD...WITH THE TRI-STATE AREA
REMAINING UNDER THE PERIPHERY OF THE RIDGE. AS A RESULT MULTIPLE
UPPER LEVEL SHORT WAVE TROUGHS WILL MOVE OVER THE AREA THROUGH THE
PERIOD. THE STRONGER TROUGHS WILL MOVE OVER THE AREA AFTER THE
WEEKEND. MEANWHILE A FRONT WILL WAFFLE BACK AND FORTH OVER THE
AREA DURING THIS PERIOD WHICH WILL CAUSE TEMPERATURES TO VARY
SOMEWHAT. AT THIS TIME RANGE DIFFICULT TO KNOW WHERE THE FRONT WILL
BE SO WILL KEEP THE CONSENSUS TEMP. FORECAST OF NEAR NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1110 PM MDT WED AUG 7 2013
AS TEMPERATURES COOL TO SATURATION...LOW CEILINGS SHOULD BECOME
PREDOMINANT BY SUNRISE...WITH OCCASIONAL REDUCTIONS IN VISIBILITY
IN LIGHT RAIN AND/OR FOG. FLIGHT CATEGORIES WILL BE SLOW TO
IMPROVE THURSDAY WITH MOIST CONDITIONS AND LIGHT SOUTHERLY WINDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR KSZ027>029-041-
042.
CO...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR COZ092.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JTL
AVIATION...024
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1133 PM CDT Wed Aug 7 2013
.UPDATE...
Issued at 940 PM CDT WED AUG 7 2013
Increase pops based on the new runs the HRRR model. The HRRR did a
good job last night forecasting the outflow boundary propagating northeast
off the MCS and causing numerous showers and thunderstorms to
develop farther north along and and south of the boundary, from
the southern counties to north of I-70.
The greatest potential for likely
to categorical pops will remain across the southern counties with
a sharp gradient in pops from east central KS, along I-70 into
north central KS along the NE border. Northeast KS may not see any
rainfall until Thursday afternoon. Also increased pops for the southern
CWA into Thursday morning as the brunt of MCS will move across southeast
KS and the northern fringe may cause heavy rainfall across the
extreme southeast counties.
&&
.SHORT TERM...(THIS EVENING THROUGH Thursday)
ISSUED AT 331 PM CDT WED AUG 7 2013
Extensive cloud cover has kept high temperatures today mainly in
upper 70s to lower to middle 80s across the area. Diffuse boundary
has been draped E to W across the area but is difficult to find
because of very weak surface wind fields. Isolated brief showers
have popped up and quickly died where greater instability exists,
near and south of boundary. Wouldn`t expect this activity to be
more than isolated late this afternoon and evening with weak
convergence and no organized upper support.
Nearly all short range (and medium range) models now consistent in
keeping weak upper disturbance south of area, so most of northeast
quarter of KS dry overnight. Only outlier is now the 09Z SREF, and
have disregarded that in coming up with POP and QPF forecast. Thus,
have considerably decreased previous forecast POPs for tonight with
highest values across far south and west forecast area and least in
far northeast KS. Latest model runs also increase influence of
surface high pressure nosing into area from the upper
midwest/western Great Lakes. This will also inhibit chances for
thunderstorms on Thursday as well, with best chances still south and
west and lowest chances northeast. With this guidance, would not
expect any significantly heavy precipitation and very low chances
for any new flooding, or increase on current river flooding through
Thursday.
.LONG TERM...(Thursday NIGHT THROUGH Wednesday)
ISSUED AT 331 PM CDT WED AUG 7 2013
Thursday evening through Saturday...
On Thursday evening, widespread moderate to at times heavy rainfall
is expected to spread northeast through the cwa. Weak mid level flow
will allow a slow northeast progression of the main shortwave trof
and therefore prolonged duration of scattered showers and
thunderstorms in the area. Strong southerly fetch of moisture
combined with warm air overriding the h85 front is expected to
center heaviest rainfall along and just north of the axis. Latest
model runs of the GFS and NAM are beginning to focus higher qpf
values just south and east of the cwa. This will need to be
monitored for consistency in consideration of flood potential. Areas
especially south of Interstate 70 who have persistently seen
rainfall each evening and/or have had flooding issues need to be
most aware to flash flooding potential from Thursday evening into
Friday. Based on the uncertainty mentioned will defer issuing flood
watch until next issuance. Where heavy precip does develop forecast
soundings depict completely saturated columns during this period
with pwat values extending above 2 inches. Showers and thunderstorms
should gradually exit the area through the day on Friday before
surface high builds southward Friday evening. Cloud cover gradually
clearing out with exiting showers should hold temps to the upper 70s
and low 80s on Friday. Light northeast winds hover around 10 mph.
Ridge flattens out Saturday with mid level zonal flow keeping most
of the rain showers out of the area. Cool air advection filtering
southward on the backside of the cool front will keep highs quite
pleasant for August in the low 80s. Slightly drier air accompanying
the wave should alleviate dewpoints a bit into the low 60s. The 12Z
NAM and ECMWF try to redevelop scattered convection over east
central areas during the late aftn in vcnty of the frontal boundary.
With this being the only run will keep forecast dry for now and
monitor model trends in upcoming forecasts.
Saturday evening through Wednesday...
On Sunday an upper trof begins to deepen across the Ontario region.
A series of embedded waves will continue to bring off and on showers
and thunderstorm chances. GFS has pretty consistent between each run
by carrying southward a sfc trough and complex of showers and
thunderstorms southeast Sunday evening into Monday. Frontal boundary
accompanying the trough becomes nearly stationary over central
Kansas with a similar pattern for precip chances through Wednesday.
Confidence is not high after Monday as the 12Z ECMWF has been
inconsistent with the frontal boundary positioning well south of
the cwa and therefore keeping much of the period dry. Temperatures
while progged to be slightly warmer will largely depend on rainfall
and cloud cover. For now will keep highs in the low to mid 80s with
lows in the 60s.
&&
.AVIATION...(For the 06Z TAFs through 06Z Thursday Night)
Issued at 1129 PM CDT WED AUG 7 2013
The complex of storms across southwest KS may reach the TAF sites
late this morning according to some models. I may place VCTS from
16Z through 19Z. A much stronger upper disturbance will bring a
better chance for thunderstorms at the TAF sites after 3Z Friday
and I may insert a VCTS group in the TAFS for later Tonight.
Expect VFR conditions outside of possible Thunderstorms.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Gargan
SHORT TERM...PHILLIPS
LONG TERM...BOWEN
AVIATION...Gargan
AREA FORECAST DISCUSSION
NWS JACKSON KY
413 AM EDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEWPOINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 137 AM EDT THU AUG 8 2013
SIMILAR SITUATION TO LAST NIGHT...WITH SCT PRECIP ACROSS THE AREA AND
CLOUD HEIGHTS VARYING FROM POCKETS OF MVFR TO MID LEVEL VFR ACROSS
THE AREA. WHERE THE TAF SITES WILL CONTINUE TO FALL WITHIN THIS
PATTERN WILL BE THE MAIN CONCERN OVERNIGHT. FOR THE MOST
PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS INFLUENCED BY THE
PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES WILL DEVELOP IN THE
MORNING...WITH POSSIBLE MVFR CIGS EXPECTED WITH ONSET. THE EXACT SET
UP OF THESE STORMS IN RELATION TO HOW THEY WILL AFFECT THE TAF SITES
IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY SHOWER OR THUNDERSTORM DOES
IMPACT A SITE DURING THE DAY...VIS COULD TEMPORARILY BE REDUCED BELOW
MVFR. SHOWERS AND THUNDERSTORMS WILL DIE DOWN TOMORROW EVENING WITH
LOSS OF DAYTIME HEATING...THOUGH SOME SCT CONVECTION IS STILL
POSSIBLE THROUGH THE REMAINDER OF THE TAF PERIOD. MUCH LIKE
TONIGHT...EXPECT OVERALL CONDITIONS TO IMPROVE TO VFR WITH SOME
POSSIBLE ADJUSTMENTS IF A SHOWER OR LINGERING THUNDERSTORM PASSES OVER
TAF SITE. AS FAR AS FOG OVERNIGHT...SOME TEMPORARY BR IS BEING
REPORTED AT KJKL IN CONJUNCTION WITH THE RAIN THAT JUST PASSED OVER
INTERACTING WITH THE WARM HUMID CONDITIONS. OTHERWISE...WITH CLOUD COVER
ACROSS MUCH OF THE REGION...ANY WIDESPREAD FOG DEVELOPMENT IS
UNLIKELY...ESPECIALLY TO A DEGREE THAT IT WILL AFFECT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
137 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1214 AM EDT THU AUG 8 2013
UPDATED POPS TO ACCOUNT FOR POSSIBILITY OF DEVELOPMENT OUTSIDE OF
MAIN SHIELD OF PRECIP CURRENTLY OVER THE NW AND CENTRAL CWA.
CONVECTION IN THE CWA SEEMS TO BE FAIRLY LIGHT WITH A DIMINISHING
TREND OVER THE LAST HOUR...BUT EXPECT SOME LIGHT RAIN AND A POSSIBLE
RUMBLE OF THUNDER TO CONTINUE OVER THE NEXT FEW HOURS FOR THE ABOVE
MENTIONED AREAS. MEANWHILE...ISOLATED CONVECTION TO OUR SW WILL MOVE
EASTWARD INTO THE AREA...THEN INCREASE IN COVERAGE AS WE WORK INTO
TOMORROW MORNING. ALSO UPDATED ONGOING TEMPS/DEW POINTS/AND WIND
FORECASTS WITH LATEST OBSERVATIONS TO MAKE SURE THEY REFLECTED THE
MOST CURRENT CONDITIONS.
UPDATE ISSUED AT 1102 PM EDT WED AUG 7 2013
RAIN IS STARTING TO PUSH INTO AREAS FROM MOUNT STERLING TO MOUNT
VERNON...BUT IS BEGINNING TO FALL APART. HRRR SEEMS TO HAVE A GOOD
HANDLE ON THIS TREND WITH THE CURRENT COMPLEX COLLAPSING WITH VERY
LITTLE FOR THE REST OF THE NIGHT. UPDATE HAS BEEN SENT.
UPDATE ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED ACROSS EASTERN
KENTUCKY. HAVE SEEN SOME NEW DEVELOPMENT OUT WEST OF LEXINGTON. THIS
ACTIVITY COULD MAKE IT INTO THE I-75 CORRIDOR OVER THE NEXT FEW
HOURS...BUT STILL SOME QUESTION IF THIS WILL MAKE IT INTO AREAS
FURTHER EAST. FOR NOW...GOING TO DOWNPLAY POPS FOR THE REST OF THE
NIGHT GIVEN THE CURRENT LACK OF ORGANIZED ACTIVITY. LATEST HRRR HAS
ALMOST NO SHOWER OR THUNDERSTORM ACTIVITY ACROSS THE AREA UNTIL 11Z.
THUS...THE DOWNWARD TREND IN POPS SEEMS REASONABLE. CAN`T IGNORE
THOSE HIGH PW`S NEAR 2 LATER TONIGHT...SO IT WON`T TAKE MUCH TO GET
SOME LOCALLY HEAVY RAIN...BUT STILL PLANNING TO PUSH ANY MENTION
UNTIL AFTER 12Z.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT WED AUG 7 2013
AFTER INITIAL ROUND OF SHOWERS AND A FEW THUNDERSTORMS THIS MORNING
CONVECTION HAS REMAINED LIMITED THIS AFTERNOON...WITH MOSTLY
SCATTERED SHOWERS...AND VERY LITTLE THUNDER. CLOUD COVER HAS INHIBITED
DESTABILIZATION AND WITH LOSS OF DAYTIME HEATING EXPECT CONVECTION TO
DIMINISH EVEN FURTHER THIS EVENING.
HOWEVER THIS WILL BE TEMPORARY...WITH A MID LEVEL SHORT WAVE TROUGH
MOVING EAST TONIGHT...AND A LOW LEVEL JET AT 8H IMPINGING ON EASTERN
KY AFTER 06Z. AT THE SAME TIME EXPECT A SURFACE WAVE OF LOW PRESSURE
TO TREK ALONG THE SURFACE FRONT TO THE NORTHWEST OF THE FORECAST AREA
THURSDAY MORNING. THERE IS GOOD MODEL AGREEMENT WITH INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS LATE TONIGHT INTO THE DAY ON
THURSDAY. DETERMINISTIC MODELS ALONG WITH THE SERF ARE POINTING
TOWARDS PRECIPITABLE WATER IN EXCESS OF 2 INCHES BY THURSDAY
MORNING. PRECIPITABLE WATER SHOULD APPROACH OR EXCEED THE 99TH
PERCENTILE. BASED ON THIS WILL ADD THE THREAT OF HEAVY RAIN TO THE
THURSDAY FORECAST AND THE HAZARDOUS WEATHER OUTLOOK. WITH ALL THIS IN
MIND WILL INCREASE RAIN PROBABILITIES LATE TONIGHT TO LIKELY IN THE
WEST...THEN LIKELY ACROSS THE ENTIRE AREA ON THURSDAY...BEFORE
DECREASING CHANCES AGAIN LATE IN THE DAY THURSDAY.
WITH THE FRONT STALLING SOMEWHERE IN THE OH VALLEY...THE TREAT OF
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THURSDAY NIGHT. THERE IS
LESS MODEL AGREEMENT ON THE TIMING OF THE NEXT SHORT WAVE WHICH WOULD
TRIGGER ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS BUT FOR FOR NOW
WILL CONTINUE THE PREVIOUS FORECAST IDEA OF INCREASING CHANCES AGAIN
LATE THURSDAY NIGHT.
HIGH DEWPOINTS WILL KEEP MINIMUM TEMPERATURES AROUND 70 TONIGHT AND
AGAIN THURSDAY NIGHT. WITH RAIN AND CLOUD IN THE FORECAST ON
THURSDAY...WILL GO WITH HIGHS IN THE LOWER 80S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 PM EDT WED AUG 7 2013
UNSETTLED WEATHER WILL CONTINUE INTO THE LONG TERM PERIOD. THE PERIOD
SHOULD BEGIN WITH A NEARLY STATIONARY BOUNDARY ACROSS THE OH VALLEY
EXTENDING SOUTHWEST INTO THE OH VALLEY FROM LOW PRESSURE OVER QUEBEC.
THERE MAY BE A WAVE OR SERIES OF SFC WAVES ALONG THE BOUNDARY TO OUR
WEST AT THAT POINT AS DISTURBANCES MOVING INTO THE REGION. AT THE
START OF THE PERIOD UPPER LEVEL RIDGING IS EXPECTED TO EXTEND ACROSS
THE SOUTHERN STATES AND NORTH INTO THE ROCKIES. AN UPPER LEVEL LOW
SHOULD BE ROTATING TO THE NORTH OF THE GREAT LAKES FROM ONTARIO.
THERE WILL PROBABLY BE SOME SHORTWAVES ROTATING TOWARD THE LOWER OH
VALLEY FROM THE PLAINS...BUT THERE ARE MODEL DIFFERENCES IN TIMING.
THE MODELS GRADUALLY SAG THE BOUNDARY SOUTH OF THE OH RIVER AND
EVENTUALLY INTO THE JKL CWA AND STRING IT OUT MORE WEST TO EAST AS THE
UPPER LOW WORKS TOWARD THE MARITIMES OVER THE WEEKEND. FROM EARLY TO
THE MIDDLE PART OF NEXT WEEK...THE TROUGH SHOULD DEEPEN AGAIN OVER
EASTERN CANADA AND THE NORTHEAST AS ANOTHER UPPER LEVEL LOW ROTATES
FROM THE HUDSON BAY REGION NORTH OF THE GREAT LAKES AND TOWARD THE
MARITIMES. THE MODEL CONSENSUS FROM EARLY TO THE MIDDLE PART OF NEXT
WEEK IS FOR MORE AMPLIFIED PATTERN WITH THE BOUNDARY PUSHING SOUTH OF
THE AREA...BUT WEST NORTHWEST UPPER FLOW SHOULD REMAIN. DISTURBANCES
IN THIS FLOW WILL STILL KEEP A THREAT OF CONVECTION IN THE PICTURE
FOR AT LEAST MON AND TUE...ESPECIALLY EACH AFTERNOON AND EVENING.
ENOUGH DRIER AIR MAY WORK INTO THE REGION LATE IN THE PERIOD IF THE
12Z ECMWF VERIFIES FOR DRY WEATHER ON WEDNESDAY OR TUESDAY AND
WEDNESDAY. HOWEVER...MODEL TO MODEL DIFFERENCES AND RUN TO RUN
DIFFERENCE REMAIN AND THE EXTENDED GRID LOAD OF ISOLATED TO
SCATTERED POPS WAS REASONABLE.
PW WILL REMAIN VERY HIGH ABOVE THE 90TH TO 95TH PERCENTILE RANGE INTO
EARLY IN THE PERIOD AHEAD OF THE BOUNDARY. THERE IS THE POTENTIAL FOR
ANY CONVECTION TO HAVE DEEP WARM CLOUD DEPTH AND THEY COULD PRODUCE
AT LEAST LOCALLY HEAVY RAIN. TIMING AND STRENGTH OF PASSING UPPER
LEVEL SHORTWAVES WILL BE A KEY INGREDIENT AND CONFIDENCE IN THIS IS
NOT HIGH AT THIS POINT. HOWEVER...WE WILL HIGHLIGHT THIS IN THE HWO.
TEMPERATURES THROUGH THE PERIOD SHOULD REMAIN NEAR IF NOT A BIT BELOW
NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS EARLY IN THE PERIOD A
BIT ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 137 AM EDT THU AUG 8 2013
SIMILAR SITUATION TO LAST NIGHT...WITH SCT PRECIP ACROSS THE AREA AND
CLOUD HEIGHTS VARYING FROM POCKETS OF MVFR TO MID LEVEL VFR ACROSS
THE AREA. WHERE THE TAF SITES WILL CONTINUE TO FALL WITHIN THIS
PATTERN WILL BE THE MAIN CONCERN OVERNIGHT. FOR THE MOST
PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS INFLUENCED BY THE
PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES WILL DEVELOP IN THE
MORNING...WITH POSSIBLE MVFR CIGS EXPECTED WITH ONSET. THE EXACT SET
UP OF THESE STORMS IN RELATION TO HOW THEY WILL AFFECT THE TAF SITES
IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY SHOWER OR THUNDERSTORM DOES
IMPACT A SITE DURING THE DAY...VIS COULD TEMPORARILY BE REDUCED BELOW
MVFR. SHOWERS AND THUNDERSTORMS WILL DIE DOWN TOMORROW EVENING WITH
LOSS OF DAYTIME HEATING...THOUGH SOME SCT CONVECTION IS STILL
POSSIBLE THROUGH THE REMAINDER OF THE TAF PERIOD. MUCH LIKE
TONIGHT...EXPECT OVERALL CONDITIONS TO IMPROVE TO VFR WITH SOME
POSSIBLE ADJUSTMENTS IF A SHOWER OR LINGERING THUNDERSTORM PASSES OVER
TAF SITE. AS FAR AS FOG OVERNIGHT...SOME TEMPORARY BR IS BEING
REPORTED AT KJKL IN CONJUNCTION WITH THE RAIN THAT JUST PASSED OVER
INTERACTING WITH THE WARM HUMID CONDITIONS. OTHERWISE...WITH CLOUD COVER
ACROSS MUCH OF THE REGION...ANY WIDESPREAD FOG DEVELOPMENT IS
UNLIKELY...ESPECIALLY TO A DEGREE THAT IT WILL AFFECT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SBH
LONG TERM...JP
AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
1216 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1214 AM EDT THU AUG 8 2013
UPDATED POPS TO ACCOUNT FOR POSSIBILITY OF DEVELOPMENT OUTSIDE OF
MAIN SHIELD OF PRECIP CURRENTLY OVER THE NW AND CENTRAL CWA.
CONVECTION IN THE CWA SEEMS TO BE FAIRLY LIGHT WITH A DIMINISHING
TREND OVER THE LAST HOUR...BUT EXPECT SOME LIGHT RAIN AND A POSSIBLE
RUMBLE OF THUNDER TO CONTINUE OVER THE NEXT FEW HOURS FOR THE ABOVE
MENTIONED AREAS. MEANWHILE...ISOLATED CONVECTION TO OUR SW WILL MOVE
EASTWARD INTO THE AREA...THEN INCREASE IN COVERAGE AS WE WORK INTO
TOMORROW MORNING. ALSO UPDATED ONGOING TEMPS/DEW POINTS/AND WIND
FORECASTS WITH LATEST OBSERVATIONS TO MAKE SURE THEY REFLECTED THE
MOST CURRENT CONDITIONS.
UPDATE ISSUED AT 1102 PM EDT WED AUG 7 2013
RAIN IS STARTING TO PUSH INTO AREAS FROM MOUNT STERLING TO MOUNT
VERNON...BUT IS BEGINNING TO FALL APART. HRRR SEEMS TO HAVE A GOOD
HANDLE ON THIS TREND WITH THE CURRENT COMPLEX COLLAPSING WITH VERY
LITTLE FOR THE REST OF THE NIGHT. UPDATE HAS BEEN SENT.
UPDATE ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS DIMINISHED ACROSS EASTERN
KENTUCKY. HAVE SEEN SOME NEW DEVELOPMENT OUT WEST OF LEXINGTON. THIS
ACTIVITY COULD MAKE IT INTO THE I-75 CORRIDOR OVER THE NEXT FEW
HOURS...BUT STILL SOME QUESTION IF THIS WILL MAKE IT INTO AREAS
FURTHER EAST. FOR NOW...GOING TO DOWNPLAY POPS FOR THE REST OF THE
NIGHT GIVEN THE CURRENT LACK OF ORGANIZED ACTIVITY. LATEST HRRR HAS
ALMOST NO SHOWER OR THUNDERSTORM ACTIVITY ACROSS THE AREA UNTIL 11Z.
THUS...THE DOWNWARD TREND IN POPS SEEMS REASONABLE. CAN`T IGNORE
THOSE HIGH PW`S NEAR 2 LATER TONIGHT...SO IT WON`T TAKE MUCH TO GET
SOME LOCALLY HEAVY RAIN...BUT STILL PLANNING TO PUSH ANY MENTION
UNTIL AFTER 12Z.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM EDT WED AUG 7 2013
AFTER INITIAL ROUND OF SHOWERS AND A FEW THUNDERSTORMS THIS MORNING
CONVECTION HAS REMAINED LIMITED THIS AFTERNOON...WITH MOSTLY
SCATTERED SHOWERS...AND VERY LITTLE THUNDER. CLOUD COVER HAS INHIBITED
DESTABILIZATION AND WITH LOSS OF DAYTIME HEATING EXPECT CONVECTION TO
DIMINISH EVEN FURTHER THIS EVENING.
HOWEVER THIS WILL BE TEMPORARY...WITH A MID LEVEL SHORT WAVE TROUGH
MOVING EAST TONIGHT...AND A LOW LEVEL JET AT 8H IMPINGING ON EASTERN
KY AFTER 06Z. AT THE SAME TIME EXPECT A SURFACE WAVE OF LOW PRESSURE
TO TREK ALONG THE SURFACE FRONT TO THE NORTHWEST OF THE FORECAST AREA
THURSDAY MORNING. THERE IS GOOD MODEL AGREEMENT WITH INCREASING
THREAT OF SHOWERS AND THUNDERSTORMS LATE TONIGHT INTO THE DAY ON
THURSDAY. DETERMINISTIC MODELS ALONG WITH THE SERF ARE POINTING
TOWARDS PRECIPITABLE WATER IN EXCESS OF 2 INCHES BY THURSDAY
MORNING. PRECIPITABLE WATER SHOULD APPROACH OR EXCEED THE 99TH
PERCENTILE. BASED ON THIS WILL ADD THE THREAT OF HEAVY RAIN TO THE
THURSDAY FORECAST AND THE HAZARDOUS WEATHER OUTLOOK. WITH ALL THIS IN
MIND WILL INCREASE RAIN PROBABILITIES LATE TONIGHT TO LIKELY IN THE
WEST...THEN LIKELY ACROSS THE ENTIRE AREA ON THURSDAY...BEFORE
DECREASING CHANCES AGAIN LATE IN THE DAY THURSDAY.
WITH THE FRONT STALLING SOMEWHERE IN THE OH VALLEY...THE TREAT OF
SHOWERS AND THUNDERSTORMS WILL CONTINUE INTO THURSDAY NIGHT. THERE IS
LESS MODEL AGREEMENT ON THE TIMING OF THE NEXT SHORT WAVE WHICH WOULD
TRIGGER ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS BUT FOR FOR NOW
WILL CONTINUE THE PREVIOUS FORECAST IDEA OF INCREASING CHANCES AGAIN
LATE THURSDAY NIGHT.
HIGH DEWPOINTS WILL KEEP MINIMUM TEMPERATURES AROUND 70 TONIGHT AND
AGAIN THURSDAY NIGHT. WITH RAIN AND CLOUD IN THE FORECAST ON
THURSDAY...WILL GO WITH HIGHS IN THE LOWER 80S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 PM EDT WED AUG 7 2013
UNSETTLED WEATHER WILL CONTINUE INTO THE LONG TERM PERIOD. THE PERIOD
SHOULD BEGIN WITH A NEARLY STATIONARY BOUNDARY ACROSS THE OH VALLEY
EXTENDING SOUTHWEST INTO THE OH VALLEY FROM LOW PRESSURE OVER QUEBEC.
THERE MAY BE A WAVE OR SERIES OF SFC WAVES ALONG THE BOUNDARY TO OUR
WEST AT THAT POINT AS DISTURBANCES MOVING INTO THE REGION. AT THE
START OF THE PERIOD UPPER LEVEL RIDGING IS EXPECTED TO EXTEND ACROSS
THE SOUTHERN STATES AND NORTH INTO THE ROCKIES. AN UPPER LEVEL LOW
SHOULD BE ROTATING TO THE NORTH OF THE GREAT LAKES FROM ONTARIO.
THERE WILL PROBABLY BE SOME SHORTWAVES ROTATING TOWARD THE LOWER OH
VALLEY FROM THE PLAINS...BUT THERE ARE MODEL DIFFERENCES IN TIMING.
THE MODELS GRADUALLY SAG THE BOUNDARY SOUTH OF THE OH RIVER AND
EVENTUALLY INTO THE JKL CWA AND STRING IT OUT MORE WEST TO EAST AS THE
UPPER LOW WORKS TOWARD THE MARITIMES OVER THE WEEKEND. FROM EARLY TO
THE MIDDLE PART OF NEXT WEEK...THE TROUGH SHOULD DEEPEN AGAIN OVER
EASTERN CANADA AND THE NORTHEAST AS ANOTHER UPPER LEVEL LOW ROTATES
FROM THE HUDSON BAY REGION NORTH OF THE GREAT LAKES AND TOWARD THE
MARITIMES. THE MODEL CONSENSUS FROM EARLY TO THE MIDDLE PART OF NEXT
WEEK IS FOR MORE AMPLIFIED PATTERN WITH THE BOUNDARY PUSHING SOUTH OF
THE AREA...BUT WEST NORTHWEST UPPER FLOW SHOULD REMAIN. DISTURBANCES
IN THIS FLOW WILL STILL KEEP A THREAT OF CONVECTION IN THE PICTURE
FOR AT LEAST MON AND TUE...ESPECIALLY EACH AFTERNOON AND EVENING.
ENOUGH DRIER AIR MAY WORK INTO THE REGION LATE IN THE PERIOD IF THE
12Z ECMWF VERIFIES FOR DRY WEATHER ON WEDNESDAY OR TUESDAY AND
WEDNESDAY. HOWEVER...MODEL TO MODEL DIFFERENCES AND RUN TO RUN
DIFFERENCE REMAIN AND THE EXTENDED GRID LOAD OF ISOLATED TO
SCATTERED POPS WAS REASONABLE.
PW WILL REMAIN VERY HIGH ABOVE THE 90TH TO 95TH PERCENTILE RANGE INTO
EARLY IN THE PERIOD AHEAD OF THE BOUNDARY. THERE IS THE POTENTIAL FOR
ANY CONVECTION TO HAVE DEEP WARM CLOUD DEPTH AND THEY COULD PRODUCE
AT LEAST LOCALLY HEAVY RAIN. TIMING AND STRENGTH OF PASSING UPPER
LEVEL SHORTWAVES WILL BE A KEY INGREDIENT AND CONFIDENCE IN THIS IS
NOT HIGH AT THIS POINT. HOWEVER...WE WILL HIGHLIGHT THIS IN THE HWO.
TEMPERATURES THROUGH THE PERIOD SHOULD REMAIN NEAR IF NOT A BIT BELOW
NORMAL FOR DAYTIME HIGHS WITH OVERNIGHT LOWS EARLY IN THE PERIOD A
BIT ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 746 PM EDT WED AUG 7 2013
SHOWERS HAVE DIMINISHED ACROSS EASTERN KENTUCKY AND TAFS WILL ALL
START OFF VFR. WITH LOTS OF LOW LEVEL MOISTURE PRESENT...SOME STRATUS
SHOULD DEVELOP OVERNIGHT...MUCH LIKE LAST NIGHT. IN ADDITION SOME
RAIN COULD START TO INVADE THE AREA TOWARDS DAYBREAK. WITH CLOUD
COVER FAIRLY HIGH TONIGHT...NO FOG EXPECTED AT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JMW
SHORT TERM...SBH
LONG TERM...JP
AVIATION...KAS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
544 AM EDT THU AUG 8 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT INTO THE AREA TODAY AND STALL ACROSS THE
HIGHER TERRAIN THROUGH FRIDAY. A COLD FRONT MOVES THROUGH ON
FRIDAY AND FRIDAY EVENING. HIGH PRESSURE BUILDS IN FOR THE END OF
THE WEEKEND AND INTO EARLY NEXT WEEK. LOW PRESSURE WILL APPROACH
FROM THE WEST IN THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE...SCT WAA SHRA ARE PUSHING ACROSS THE AREA ATTM...ROUGHLY
ALIGNED WITH NH/ME BORDER. A FEW OF THE STRONGER CELLS HAVE HAD
SOME IN CLOUD LIGHTNING WITH THEM...BUT MOSTLY JUST SOME BRIEF
-SHRA. THIS WAVE OF PCPN WILL CONTINUE EWD THRU THE MORNING HOURS.
FARTHER W...BROKEN LINE OF SHRA/TSTMS FROM THE ST. LAWRENCE VALLEY
SWWD TOWARDS KBUF CONTINUES TO TRACK EWD. COMPLEX OF TSTMS NEAR
THE EASTERN TOWNSHIPS WILL LIKELY EFFECT NRN COOS AND THE WRN ME
MTNS. SATELLITE TRENDS SUGGEST WEAKENING IS OCCURRING...WITH CLOUD
TOPS WARMING AND LIGHTNING DECREASING. ACROSS WRN NY...COMPLEX OF
TSTMS THERE IS MAINTAINING STRENGTH WITH CLOUD TOPS COOLING AND
LIGHTNING INCREASING. THIS GROWING COMPLEX MAY BE THE REASON FOR
THE RELATIVE LACK OF CONVECTIVE ACTIVITY ACROSS THE ADIRONDACKS
AND VT. HAVE TRENDED POP BASED ON THE LATEST HRRR AND RADAR.
PREVIOUS DISCUSSION...FNT WILL APPROACH THE AREA TODAY AND BRING
AT LEAST A COUPLE ROUNDS OF SHRA/TSTMS.
EARLY TODAY AN INCREASINGLY MOISTENING ATMOSPHERE WILL RESULT IN
CLOUDS SPREADING EWD AND THICKENING. ADDITIONALLY...WAA WILL
SUPPORT WIDELY SCT SHRA ACROSS THE AREA THRU SUNRISE. A LINE OF
SHRA AND TSTMS ALONG THE FNT WILL ALSO PUSH EWD INTO WRN ZONES IN
THE NEXT SEVERAL HOURS. SO IN THE NEAR TERM HAVE TRIED TO TIME
POP WITH THIS TREND...WHICH THE HRRR SEEM TO HAVE A DECENT HANDLE
ON. A BLEND OF THAT AND THE LOCAL WRF WAS USED AS THE BASE FOR THE
FIRST HALF OF THE DAY.
AS THIS EARLY CONVECTION WEAKENS AND MOVES E...EXPECT THAT A FEW
PARTIAL BREAKS IN THE OVERCAST WILL DEVELOP THIS AFTERNOON. IT IS
THESE POCKETS OF SFC HEATING THAT WILL BECOME THE FOCUS FOR THE
AFTERNOON FORECAST. LAPSE RATES ARE MARGINAL AT BEST...BUT DEW
POINTS INCREASING TO THE UPR 60S TO NEAR 70 WILL SUPPORT MODERATE
INSTABILITY FOR LOCATIONS THAT CAN GLIMPSE SOME SUNSHINE. AMPLE
MID LVL WLY FLOW WILL SUPPORT ENOUGH EFFECTIVE SHEAR FOR SOME
STORM ORGANIZATION. AT LEAST TRANSIENT SUPERCELL STRUCTURE WILL
LEAD TO STRONGER CONVECTION CONTAINING GUSTY WINDS AND SMALL HAIL.
GREATER THREAT IS PROBABLY WIND...AS DEEP...MOIST AIR MASS WILL BE
MORE SUPPORTIVE OF MELTING HAIL. PCPN LOADING IN THE COLUMN AND
STEEP LLVL LAPSE RATES WHERE SUN PEEKS OUT IS MORE THAN ENOUGH FOR
SOME GUSTY DOWNDRAFTS. THIS HAS BEEN ADDED TO THE GRIDS...MAINLY
ACROSS NH AND EXTREME WRN ME. NOT EXPECTING ANYTHING
WIDESPREAD...BUT AN ISOLD SEVERE WX REPORT IS ENTIRELY PSBL TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
ATTENTION THEN TURNS TO FNT STALLING ALONG OR S OF THE SRN CWFA
BORDER. TO THE S WILL BE AN EXTREMELY MOIST AIR MASS...WITH PWAT
VALUES INCREASING TO NEAR 2 INCHES. FOR THE GYX AREA THIS
REPRESENTATION AOA +2 SD ABOVE NORMAL. HEAVY RNFL IS LIKELY WITH
ANY CONVECTION...WITH EXTREME RNFL RATES AT TIMES. IN
ADDITION...BOUNDARY WILL PROVIDE A FOCUS FOR TRAINING CELLS. ATTM
UNCERTAINTY STILL EXISTS ON LOCATION FNT STALLS...BUT AS
CONFIDENCE GROWS SOME SORT OF FLOOD/FLASH FLOOD HEADLINE MAY BE
NECESSARY FOR A PORTION OF THE AREA. MUCH OF THAT MAY ALSO DEPEND
ON WHERE HEAVY RAIN FALLS TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION FRIDAY
EVENING...SWEEPING THE HIGHER SURFACE DEW POINTS AND PRECIPITABLE
WATER VALUES OFF THE COAST. MODELS STILL HAVE SOME ISSUES WITH THE
TIMING OF THE PASSAGE OF THE FRONT. HAVE USED A BLEND BETWEEN THE
VERY PROGRESSIVE...FAST MOVING FRONTAL PASSAGE WITH THE GFS/EURO
SOLUTION...AND THE SLOWER FROPA WITH THE NAM/GGEM SOLUTION.
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON
SATURDAY. HOWEVER...STILL PLENTY OF COLD AIR AND CYCLONIC FLOW ALOFT
ALLOWING FOR A FEW DIURNALLY DRIVEN SPRINKLES OR SCATTERED
SHOWERS...MAINLY ACROSS THE HIGHER TERRAIN OF THE MOUNTAINS. THIS
AIR MASS WILL BE NOTICEABLY COOLER AND DRIER. EXPECT CHILLY NIGHTS
WITH PATCHY FOG AS THIS SYSTEM BUILDS OVERHEAD.
MODELS IN GOOD AGREEMENT ADVANCING THE AREA OF HIGH PRESSURE OVER
OUR REGION SUNDAY INTO MONDAY. BY TUESDAY...LOW PRESSURE WILL
BEGIN TO EXIT THE GREAT LAKES REGION...BRINGING MORE SCATTERED
SHOWERS TO OUR REGION DURING THE MIDWEEK PERIOD.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDS EXPECTED TO DETERIORATE INTO GENERALLY MVFR
CIGS AND VSBYS AS FNT APPROACHES TODAY. SOME LOCAL IFR IS PSBL IN
NEAR COAST STRATUS OR SHRA/TSTM. IFR CONDS COULD BECOME MORE
WIDESPREAD NEAR THE COAST AS FNT STALL TONIGHT AND FRI AND DEEPER
MOISTURE WORKS NWD.
LONG TERM...SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EARLY FRIDAY
EVENING MAY BRING MVFR TO IFR CONDITIONS. EXPECT IMPROVING
CONDITIONS BEHIND A COLD FRONT FRIDAY NIGHT WITH VFR CONDITIONS
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...SUSTAINED ONSHORE FLOW WILL DEVELOP TODAY AHEAD OF AN
APPROACHING FNT. THIS WILL GRADUALLY BUILD SEAS TO NEAR 5 FT BY
LATE THIS EVENING...DESPITE WINDS REMAINING BLO 25 KTS. USED A
BLEND OF THE NAM BASED SWAN WITH THE WNA4 IN THE FIRST PERIOD...AS
GFS IS USUALLY TOO AGGRESSIVE WITH WINDS AND SEAS IN SLY FLOW.
LONG TERM...SOUTHERLY FLOW WILL END FRIDAY EVENING. HOWEVER SEAS
STILL EXPECTED TO BE RELATIVELY HIGH IN THE 4 TO 6 FOOT RANGE.
THEREFORE....SMALL CRAFT ADVISORIES MAY STILL BE NEEDED THROUGH
MUCH OF FRIDAY NIGHT AND POSSIBLY INTO EARLY SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
LEGRO/JC
AREA FORECAST DISCUSSION
NWS GRAY ME
318 AM EDT THU AUG 8 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT INTO THE AREA TODAY AND STALL ACROSS THE
HIGHER TERRAIN THROUGH FRIDAY. A COLD FRONT MOVES THROUGH ON
FRIDAY AND FRIDAY EVENING. HIGH PRESSURE BUILDS IN FOR THE END OF
THE WEEKEND AND INTO EARLY NEXT WEEK. LOW PRESSURE WILL APPROACH
FROM THE WEST IN THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
FNT WILL APPROACH THE AREA TODAY AND BRING AT LEAST A COUPLE ROUNDS
OF SHRA/TSTMS.
EARLY TODAY AN INCREASINGLY MOISTENING ATMOSPHERE WILL RESULT IN
CLOUDS SPREADING EWD AND THICKENING. ADDITIONALLY...WAA WILL
SUPPORT WIDELY SCT SHRA ACROSS THE AREA THRU SUNRISE. A LINE OF
SHRA AND TSTMS ALONG THE FNT WILL ALSO PUSH EWD INTO WRN ZONES IN
THE NEXT SEVERAL HOURS. SO IN THE NEAR TERM HAVE TRIED TO TIME
POP WITH THIS TREND...WHICH THE HRRR SEEM TO HAVE A DECENT HANDLE
ON. A BLEND OF THAT AND THE LOCAL WRF WAS USED AS THE BASE FOR THE
FIRST HALF OF THE DAY.
AS THIS EARLY CONVECTION WEAKENS AND MOVES E...EXPECT THAT A FEW
PARTIAL BREAKS IN THE OVERCAST WILL DEVELOP THIS AFTERNOON. IT IS
THESE POCKETS OF SFC HEATING THAT WILL BECOME THE FOCUS FOR THE
AFTERNOON FORECAST. LAPSE RATES ARE MARGINAL AT BEST...BUT DEW
POINTS INCREASING TO THE UPR 60S TO NEAR 70 WILL SUPPORT MODERATE
INSTABILITY FOR LOCATIONS THAT CAN GLIMPSE SOME SUNSHINE. AMPLE
MID LVL WLY FLOW WILL SUPPORT ENOUGH EFFECTIVE SHEAR FOR SOME
STORM ORGANIZATION. AT LEAST TRANSIENT SUPERCELL STRUCTURE WILL
LEAD TO STRONGER CONVECTION CONTAINING GUSTY WINDS AND SMALL HAIL.
GREATER THREAT IS PROBABLY WIND...AS DEEP...MOIST AIR MASS WILL BE
MORE SUPPORTIVE OF MELTING HAIL. PCPN LOADING IN THE COLUMN AND
STEEP LLVL LAPSE RATES WHERE SUN PEEKS OUT IS MORE THAN ENOUGH FOR
SOME GUSTY DOWNDRAFTS. THIS HAS BEEN ADDED TO THE GRIDS...MAINLY
ACROSS NH AND EXTREME WRN ME. NOT EXPECTING ANYTHING
WIDESPREAD...BUT AN ISOLD SEVERE WX REPORT IS ENTIRELY PSBL TODAY.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
ATTENTION THEN TURNS TO FNT STALLING ALONG OR S OF THE SRN CWFA
BORDER. TO THE S WILL BE AN EXTREMELY MOIST AIR MASS...WITH PWAT
VALUES INCREASING TO NEAR 2 INCHES. FOR THE GYX AREA THIS
REPRESENTATION AOA +2 SD ABOVE NORMAL. HEAVY RNFL IS LIKELY WITH
ANY CONVECTION...WITH EXTREME RNFL RATES AT TIMES. IN
ADDITION...BOUNDARY WILL PROVIDE A FOCUS FOR TRAINING CELLS. ATTM
UNCERTAINTY STILL EXISTS ON LOCATION FNT STALLS...BUT AS
CONFIDENCE GROWS SOME SORT OF FLOOD/FLASH FLOOD HEADLINE MAY BE
NECESSARY FOR A PORTION OF THE AREA. MUCH OF THAT MAY ALSO DEPEND
ON WHERE HEAVY RAIN FALLS TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION FRIDAY
EVENING...SWEEPING THE HIGHER SURFACE DEW POINTS AND PRECIPITABLE
WATER VALUES OFF THE COAST. MODELS STILL HAVE SOME ISSUES WITH THE
TIMING OF THE PASSAGE OF THE FRONT. HAVE USED A BLEND BETWEEN THE
VERY PROGRESSIVE...FAST MOVING FRONTAL PASSAGE WITH THE GFS/EURO
SOLUTION...AND THE SLOWER FROPA WITH THE NAM/GGEM SOLUTION.
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON
SATURDAY. HOWEVER...STILL PLENTY OF COLD AIR AND CYCLONIC FLOW ALOFT
ALLOWING FOR A FEW DIURNALLY DRIVEN SPRINKLES OR SCATTERED
SHOWERS...MAINLY ACROSS THE HIGHER TERRAIN OF THE MOUNTAINS. THIS
AIR MASS WILL BE NOTICEABLY COOLER AND DRIER. EXPECT CHILLY NIGHTS
WITH PATCHY FOG AS THIS SYSTEM BUILDS OVERHEAD.
MODELS IN GOOD AGREEMENT ADVANCING THE AREA OF HIGH PRESSURE OVER
OUR REGION SUNDAY INTO MONDAY. BY TUESDAY...LOW PRESSURE WILL
BEGIN TO EXIT THE GREAT LAKES REGION...BRINGING MORE SCATTERED
SHOWERS TO OUR REGION DURING THE MIDWEEK PERIOD.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDS EXPECTED TO DETERIORATE INTO GENERALLY MVFR
CIGS AND VSBYS AS FNT APPROACHES TODAY. SOME LOCAL IFR IS PSBL IN
NEAR COAST STRATUS OR SHRA/TSTM. IFR CONDS COULD BECOME MORE
WIDESPREAD NEAR THE COAST AS FNT STALL TONIGHT AND FRI AND DEEPER
MOISTURE WORKS NWD.
LONG TERM...SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EARLY FRIDAY
EVENING MAY BRING MVFR TO IFR CONDITIONS. EXPECT IMPROVING
CONDITIONS BEHIND A COLD FRONT FRIDAY NIGHT WITH VFR CONDITIONS
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...SUSTAINED ONSHORE FLOW WILL DEVELOP TODAY AHEAD OF AN
APPROACHING FNT. THIS WILL GRADUALLY BUILD SEAS TO NEAR 5 FT BY
LATE THIS EVENING...DESPITE WINDS REMAINING BLO 25 KTS. USED A
BLEND OF THE NAM BASED SWAN WITH THE WNA4 IN THE FIRST PERIOD...AS
GFS IS USUALLY TOO AGGRESSIVE WITH WINDS AND SEAS IN SLY FLOW.
LONG TERM...SOUTHERLY FLOW WILL END FRIDAY EVENING. HOWEVER SEAS
STILL EXPECTED TO BE RELATIVELY HIGH IN THE 4 TO 6 FOOT RANGE.
THEREFORE....SMALL CRAFT ADVISORIES MAY STILL BE NEEDED THROUGH
MUCH OF FRIDAY NIGHT AND POSSIBLY INTO EARLY SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
LEGRO/JC
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1257 AM EDT THU AUG 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE SOUTHEAST OF THE AREA OVERNIGHT. A COLD FRONT
WILL APPROACH FROM QUEBEC THURSDAY NIGHT...THEN CROSS THE REGION
FRIDAY WHILE LOW PRESSURE MOVES NORTH ALONG THE FRONT.
&&
.NEAR TERM /THROUGH TODAY/...
1250 AM UPDATE...CLOUDS WILL CONTINUE TO INCREASE OVERNIGHT AND
THE CLOUD COVER WILL KEEP TEMPERATURES FROM FALLING ALL THAT MUCH.
THEREFORE...HAVE RAISED OVERNIGHT LOWS A FEW DEGREES. OTHERWISE
THE FORECAST STILL LOOKS ON TRACK. THE LATEST HRRR AND RUC INDICATE
THAT SHOWERS WILL START TO MAKE IT INTO THE WESTERN ZONES AFTER
06Z AND THE CURRENT GRIDDED DATABASE SEEMS TO HAVE A GOOD HANDLE ON
THIS.
PREVIOUS DISCUSSION
HIGH PRESSURE WILL MOVE EAST OVERNIGHT. CLEAR SKIES AND LIGHT
WINDS WILL ALLOW TEMPERATURES TO FALL INTO THE LOW 50S WITH A FEW
READINGS IN THE UPPER 40S POSSIBLE TOWARDS THE EASTERN BORDER OF
THE STATE. CLOUDS INCREASE THURSDAY AS AN OCCLUDED FRONT
APPROACHES. THIS FRONT IS ASSOCIATED WITH A CUT OFF UPPER LOW IN
WESTERN ONTARIO. A SHORTWAVE ROTATING AROUND THE LOW WILL WEAKEN
AS IT MOVES INTO QUEBEC. AS A RESULT...THE FRONT WILL ALSO WEAKEN
AS IT MOVES INTO THE FORECAST AREA THURSDAY MORNING. BESIDES
INCREASING CLOUDS...SOME SHOWER ACTIVITY IS EXPECTED WITH A TENTH
OR TWO OF AN INCH OF RAIN POSSIBLE. THE SURFACE FRONT IS NOT
EXPECTED TO CROSS THE STATE THURSDAY...BUT MORE HUMID AIR WILL BE
INTRODUCED IN WESTERN PORTIONS OF THE FORECAST AREA THURSDAY
AFTERNOON. THIS HUMID AIR AND SOME PERIODS OF AFTERNOON SUNSHINE
IS EXPECTED TO DESTABILIZE THE ATMOSPHERE AND ALLOW SOME
THUNDERSTORMS TO DEVELOP...MOSTLY FOR PISCATAQUIS COUNTY AND FAR
SOUTHWESTERN PENOBSCOT COUNTY. ELSEWHERE...A COMBINATION OF CLOUD
COVER AND MARINE INFLUENCES SHOULD PREVENT MUCH DAYTIME HEATING
AND INSTABILITY. HIGHS WILL ONLY REACH THE UPPER 60S TO LOW 70S.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
A COLD FRONT WILL APPROACH THURSDAY NIGHT WITH A CHANCE OF SHOWERS
ACROSS THE FORECAST AREA IN ADVANCE OF THE FRONT. THE COLD FRONT
THEN CROSSES THE REGION FRIDAY THROUGH FRIDAY NIGHT WHILE AN AREA
OF LOW PRESSURE MOVES NORTH ALONG THE FRONT. AN AREA OF RAIN WILL
CROSS THE REGION FRIDAY THROUGH EARLY FRIDAY NIGHT...WITH THE
SLIGHT CHANCE OF A THUNDERSTORM FRIDAY AFTERNOON. THE
PRECIPITATION WILL THEN TAPER TO SHOWERS IN THE WAKE OF THE FRONT
LATER FRIDAY NIGHT. THE COLD FRONT WILL MOVE EAST OF THE REGION
EARLY SATURDAY...WHILE AN UPPER LOW TRACKS NORTH OF MAINE SATURDAY
AFTERNOON. COULD HAVE AN ISOLATED SHOWER DOWNEAST EARLY SATURDAY.
OTHERWISE...EXPECT PARTLY/MOSTLY SUNNY SKIES DOWNEAST SATURDAY. A
CHANCE OF SHOWERS COULD EXIST ACROSS NORTHERN AREAS INTO THE
EARLY AFTERNOON SATURDAY WITH THE UPPER LOW. OTHERWISE...EXPECT
PARTLY/MOSTLY CLOUDY SKIES ACROSS NORTHERN AREAS DURING THE
MORNING WITH DECREASING CLOUDS DURING THE AFTERNOON. HIGH PRESSURE
THEN BUILDS ACROSS THE REGION SATURDAY NIGHT. TEMPERATURES WILL BE
AT BELOW NORMAL LEVELS FRIDAY...WITH SLIGHTLY BELOW NORMAL LEVEL
TEMPERATURES SATURDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
SUNDAY WILL FEATURE MAINLY SUNNY SKIES WITH SEASONAL TEMPERATURES
TO ROUND OUT THE WEEKEND ALONG WITH COMFORTABLY LOW LEVELS OF
HUMIDITY. EXPECT MAINLY CLEAR AND COOL CONDITIONS SUNDAY NIGHT
UNDER HIGH PRESSURE. CLOUDS BEGIN TO INCREASE MONDAY WITH THE
APPROACH OF THE NEXT SYSTEM. THIS SYSTEM WILL BRING A CHANCE OF
SHOWERS ARRIVING BY LATE DAY MONDAY AND LASTING INTO TUESDAY.
CONDITIONS WILL CLEAR OUT ONCE AGAIN FOR THE MIDDLE OF NEXT WEEK.
AT THIS POINT NO MAJOR HOT SPELLS ARE ON THE HORIZON WITH THE
OVERALL PATTERN FAVORING AVERAGE TO BELOW AVERAGE TEMPERATURES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
NEAR TERM: VFR THROUGH TONIGHT. MVFR CEILINGS ARE EXPECTED TO
DEVELOP THURSDAY MORNING IN SHOWERS.
SHORT TERM: MVFR/IFR...WITH OCCASIONAL LIFR...CONDITIONS ARE
EXPECTED THURSDAY NIGHT INTO EARLY FRIDAY NIGHT. VFR/MVFR
CONDITIONS ARE EXPECTED LATER FRIDAY NIGHT. OCCASIONAL MVFR
CONDITIONS ARE POSSIBLE ACROSS NORTHERN AREAS EARLY SATURDAY.
OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE REGION SATURDAY
THROUGH SATURDAY NIGHT. EXPECT VFR SUNDAY INTO MONDAY WITH
MVFR/IFR POSSIBLE BY TUESDAY.
&&
.MARINE...
NEAR TERM: WINDS WILL INCREASE THURSDAY WITH GUSTS UP TO 15 KTS
FROM THE SOUTH. SEAS WILL ALSO INCREASE TOWARDS 3 TO 4 FEET BY
LATER THURSDAY.
SHORT TERM: SMALL CRAFT ADVISORY LEVEL SEAS ARE POSSIBLE THURSDAY
NIGHT INTO EARLY SATURDAY. VISIBILITIES COULD BE REDUCED IN RAIN
AND FOG THURSDAY NIGHT INTO FRIDAY NIGHT...WITH A LINGERING
SHOWER POSSIBLE EARLY SATURDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DUDA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
525 AM EDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU AUG 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP MID LEVEL LOW OVER
NRN ONTARIO JUST E OF THE MANITOBA/ONTARIO BORDER. FOR THIS TIME OF
YEAR...THE LOW IS UNUSUALLY DEEP WITH 500MB HEIGHTS 2.5 STANDARD
DEVIATIONS BELOW THE LONG TERM AVG. THE UPPER LAKES ARE UNDER THE
SRN PORTION OF ITS RATHER EXPANSIVE CIRCULATION. IN THE WAKE OF THE
SHORTWAVES THAT PASSED ACROSS THE UPPER LAKES YESTERDAY...A DRY AIR
MASS HAS PUSHED INTO UPPER MI. COMBINED WITH CLEAR SKIES AND
LIGHT/CALM WIND...TEMPS HAVE ONCE AGAIN DIPPED AS LOW AS THE UPPER
30S IN SOME OF THE TRADITIONAL COLD SPOTS IN THE INTERIOR (DOE LAKE
AND SPINCICH LAKE IN PARTICULAR). JUST TO THE W...A SHORTWAVE THAT
WAS MUCH MORE WELL DEFINED YESTERDAY AFTN HAS WEAKENED/SHEARED E
INTO MN...AND IT IS SPREADING A BAND OF MID CLOUDS ACROSS NRN MN AND
WRN LAKE SUPERIOR. AFTER DIMINISHING...A BAND OF SHRA HAS
REDEVELOPED ACROSS NRN MN IN ASSOCIATION WITH THE SHORTWAVE. TO THE
NW OVER MANITOBA...A SHORTWAVE SPOKE IS EVIDENT ROTATING AROUND THE
DEEP MIDLEVEL LOW OVER NRN ONTARIO. BOTH OF THESE SHORTWAVES WILL
HAVE SOME IMPACT ON THE WEATHER HERE TODAY/TONIGHT.
FIRST UP...THE WEAKENING SHORTWAVE OVER MN WILL PASS ACROSS THE AREA
THIS MORNING. SEVERAL OF THE HIGH RES MODELS INCLUDING NAM AND HIGH
RES WRF-ARW/WRF-NMM HAVE DONE A NICE JOB PICKING UP ON THE LOCATION
OF SHRA TO THE W AND SUGGEST SHRA WILL TEND TO DISSIPATE AS THEY
SHIFT E INTO WRN UPPER MI THIS MORNING. WILL GENERALLY FOLLOW THIS
IDEA AND SPREAD ISOLD -SHRA INTO PORTIONS OF WRN UPPER MI THIS
MORNING. DURING THE AFTN...NEXT SHORTWAVE CURRENTLY ROTATING THRU
SRN MANITOBA SHOULD PROVIDE FORCING FOR ISOLD TO PERHAPS SCT AFTN
CONVECTION WITH LAKE BREEZES PROVIDING A LOW LEVEL FOCUS AS WELL.
WITH MLCAPES ONLY UP TO A COUPLE HUNDRED J/KG...THUNDER POTENTIAL IS
MINIMAL...BUT PROBABLY STILL WORTHY OF INCLUDING MENTION IN FCST.
ISOLD/SCT SHRA SHOULD SLOWLY SHIFT E AND SE TONIGHT AS PRONOUNCED
MID LEVEL DRYING PUSHES IN FROM THE W. THIS SHOULD ALSO LEAD TO
CLEARING OVER AT LEAST THE W HALF OR SO OF THE FCST AREA. LEANED
SOMEWHAT TOWARD THE LOWER SIDE OF AVBL GUIDANCE FOR MINS OVER THE W
WITH EXPECATION OF CLEARING AND A DRYING COLUMN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 518 AM EDT THU AUG 8 2013
OMEGA BLOCKING FROM ALASKA TO EASTERN CANADA WILL FINALLY BEGIN TO
BREAKDOWN...ALBEIT SLOWLY...BY THIS WEEKEND. BESIDE A CHANCE FOR
SHOWERS AND STORMS SUNDAY AFTERNOON INTO MONDAY NIGHT...THE LONG
TERM TREND WILL BE DRY AND SLIGHTLY COOLER THAN NORMAL.
FRIDAY THROUGH SATURDAY NIGHT...A DEEP CLOSED MID-LEVEL LOW OVER
NORTHERN ONTARIO WILL BE SENDING A SHORTWAVE TROUGH ACROSS THE CWA
THURSDAY NIGHT. THE ASSOCIATED COLD FRONT IS PROGGED TO CLEAR THE
CWA BY 12Z FRIDAY...WITH MUCH DRIER AIR USHERING IN BEHIND IT. SOME
LOW-LEVEL MOISTURE COULD LINGER ACROSS THE EAST HALF AFTER 12Z UNDER
INCREASING SUBSIDENCE BEHIND THE FRONT...SO KEPT SLIGHT CHANCE POPS
FOR A FEW HOURS BEYOND 12Z FOR THE FAR EAST.
THE MAIN TROUGH AXIS WILL THEN PUSH SOUTHEASTWARD ACROSS THE CWA
FRIDAY AFTERNOON INTO LATE FRIDAY NIGHT. WHILE MOISTURE IS LACKING
IN THE MID-LEVELS...H8 TO H7 FGEN UNDER MODEST MID-LEVEL
Q-VECTOR CONVERGENCE WILL LEAD TO INCREASED CLOUDINESS BELOW H5. THE
NAM IS THE ONLY MODEL TO INDICATE A SHOT AT ISOLATED SHOWERS ACROSS
THE NORTH CLOSER TO THE MAIN FORCING. HAVE OPTED TO KEEP ANY PRECIP
OUT OF THE FORECAST FOR NOW GIVEN VERY DRY LOW LEVELS AND THAT MOST
MODELS HAVE BEEN CONSISTENT WITH ALL PRECIP REMAINING OUT OF THE
CWA. MODEL TRENDS HAVE ALSO SHOWED A STRONGER PRESSURE
GRADIENT...ESPECIALLY NORTH....WITH THE TROUGH PASSAGE. WEAK
STABILITY SUGGESTS THAT MIXING COULD BRING GUSTY WNW OF UP TO 25 MPH
TO MUCH OF THE NORTH HALF BY THE AFTERNOON.
SFC HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WITH
MID-LEVEL SHORTWAVE RIDGING FRIDAY NIGHT THROUGH SATURDAY. GENERALLY
CLEAR SKIES AND LOW PWATS OF AROUND 0.5 INCHES WILL BE CONDUCIVE FOR
GOOD RADIATIONAL COOLING ACROSS MUCH OF THE CWA...PARTICULARLY THE
INTERIOR WEST HALF. HAVE FOLLOWED THE PREVIOUS SHIFTS TREND OF
LOWERING TEMPS. WIDESPREAD 40S ARE LIKELY FOR ALL BUT THE IMMEDIATE
GREAT LAKES SHORELINES. WEAK LOW-LEVEL MOISTURE RETURN WILL BEGIN
ACROSS THE WEST SATURDAY AFTERNOON AS THE SFC HIGH MOVES EAST. WITH
THIS MOISTURE INCREASE...AFTERNOON CUMULUS DEVELOPMENT WILL BE
COMMON. A FEW ISOLATED DIURNAL SHOWERS COULD EVEN BE POSSIBLE...BUT
ONCE AGAIN...CONFIDENCE IS TOO LOW TO INTRODUCE ANY PRECIP ATTM. LOW
TO MID-LEVEL CLOUDINESS WILL CONTINUE TO INCREASE WITH THE MOISTURE
RETURN SATURDAY NIGHT...KEEPING TEMPS SEVERAL DEGREES WARMER THAN
FRIDAY NIGHT.
SUNDAY THROUGH MONDAY...ANOTHER SHORTWAVE TROUGH ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN MID-LEVEL TROUGH WILL BE DIGGING SOUTHWARD
ACROSS FAR WESTERN ONTARIO LATE SATURDAY NIGHT. THE ECMWF HAS SLOWED
THIS TROUGH PASSAGE OVER THE LAST FEW RUNS...AND NOW LINES UP WELL
WITH THE GFS IN BRINGING THE MAIN TROUGH AXIS THROUGH MONDAY
EVENING. BOTH MODELS HAVE ALSO RECENTLY PICKED UP ON A WEAK LEAD
SHORTWAVE TROUGH FROM PHASING BETWEEN A PORTION OF THE MAIN TROUGH
AND A WEAK WAVE MOVING EASTWARD FROM WESTERN CANADA. THE TIMING OF
THIS WEAK WAVE IS A LITTLE DIFFERENT BETWEEN THE TWO MODELS...WITH
THE CONSENSUS BEING EARLY SUNDAY EVENING. INSTABILITY WILL BE QUITE
POOR NORTH OF THE WI BORDER AND SHOULD PRECLUDE ANY STRONG
THUNDERSTORM THREAT ATTM. THE TROUGH WILL CONTINUE TO SLOWLY WORK
EASTWARD ACROSS THE CWA AND BRING ISOLATED TO SCATTERED SHOWERS
THROUGH MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...BY THIS POINT...THE ECMWF AND GFS
HAVE SOME DISAGREEMENT ON THE STRENGTH OF THE SHORTWAVE...AND HOW
QUICK IT WILL DEPART. THE ECMWF IS MUCH QUICKER AND BRINGS GENERALLY
DRY CONDITIONS THROUGH WEDNESDAY. THE GFS SWINGS A STRONG SECONDARY
TROUGH ACROSS THE EASTERN CWA ON TUESDAY...BUT LIMITS SHOWERS TO
ONLY THE EAST HALF. STUCK WITH OVERALL MODEL CONSENSUS FOR
NOW...THROUGH MUCH OF THE PERIOD SHOULD REMAIN DRY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 144 AM EDT THU AUG 8 2013
VFR CONDITIONS WILL PERSIST THRU THE END OF THIS FCST PERIOD AT
KIWD/KCMX/KSAW. LAKE BREEZES WILL MOVE INTO KSAW LATER IN THE
AFTERNOON. PCPN CHANCE IS TOO LOW AT THIS POINT TO PUT INTO THE TAFS
AS NEXT UPPER LEVEL DISTURBANCE PASSES THROUGH TODAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT THU AUG 8 2013
EXPECT WINDS UNDER 20KT ACROSS LAKE SUPERIOR TODAY/TONIGHT UNDER A
GENERALLY WEAK PRES GRADIENT. HOWEVER...WINDS WILL BEGIN TO INCREASE
OVERNIGHT TONIGHT AHEAD OF THE NEXT COLD FRONT DROPPING SE. AN
INCREASING PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM
SOUTH CENTRAL CANADA AND LOW PRESSURE EXITING TO THE EAST ACROSS
EASTERN ONTARIO WILL CREATE W TO WNW WINDS OF 15 TO 25 KNOTS ACROSS
WESTERN LAKE SUPERIOR FRIDAY MORNING...AND CENTRAL AND EASTERN LAKE
SUPERIOR FRIDAY AFTERNOON. WEST WINDS UNDER 15 KNOTS WILL THEN BE THE
RULE THROUGH THE WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE UPPER
GREAT LAKES. ANOTHER TROUGH WILL CROSS LAKE SUPERIOR ON MONDAY AND
BRING NW WINDS UNDER 15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...07
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
330 AM CDT Thu Aug 8 2013
.SHORT TERM...(Today through Friday)
Issued at 322 AM CDT THU AUG 8 2013
Another night of conceptual forecasting as none of the 00Z solutions
have initialized the anticipated MCS riding along the KS/OK border,
and continue to poorly handle the subtle but key features emanating
out of the western trough each afternoon. The HRRR continues to
perform exceptionally well (albiet slow on timing), but its short-
term guidance only goes so far. In any case, 07Z surface analysis
depicts a strongly convergent frontal zone across nrn OK/AR with the
greatest lift once again focused about 50 miles north of this
boundary. A secondary elevated boundary, roughly juxtaposed with the
southern extent of dry surface air, extends NE from Wichita to
Clinton to Jefferson City. Developing MCV along over SW KS will
likely begin to make the turn ENE along this northern boundary. Its
also possible that additional showers/storms develop along this
elevated boundary over the next several hours, remaining /just/ south
of the CWA border.
With that said, dry northeasterly flow should keep most of the CWA
quiet through daybreak. Much like the past several nights, a sub-
synoptic occlusion should occur as the eastward advancing MCS
overtakes the W-E stationary front. This would place the southwestern
zones under the best chances for thunder by 12Z, with more
stratiform rain/embedded rumbles further north. The MCV should lift
slowly NE across the CWA during the day, with QPF diminishing.
However, the MCV passage will mark the return of deeper warm/air
moisture advection that will place us back in a preferred zone for
deep moist convection tonight and Friday. As for highs today,
generally went around 80 across the board. Despite better chances for
sunshine over the NE CWA (at least early), CAA should yield similar
readings as points further south. Convective debris/showers should
limit insolation over the srn CWA through the morning, but expect
some PM sun to boost them back up.
For tonight, the large scale mid-level trough will begin to
finally eject out of the central Rockies, establishing a surface low
across OK. Deepening southwesterly flow aloft will lift the surface
warm front back to near I-44. This will place the southern CWA in a
precarious region of strong deep layer ascent/convergence amidst
increasing moisture advection. Based only on persistence from the
past 4-5 days, greatest QPF should fall in the 06-15Z time frame
Friday. Given the frontogenetic forcing, upper support and boundary-
relative shear profiles, have significantly bumped POPs and QPF from
06Z-18Z Friday. A flash flood watch will likely be required south of
the MO river given antecedent rainfall and prospects for very heavy
rainfall tonight/Friday morning.
Highs Friday honestly a hedge toward some afternoon clearing, but
could conceivably end up in the low-mid 70s if this doesn`t occur.
Friday Night remains the biggest question mark given the large model
spread in timing of the upper trough passage. Areas along/ahead of
this mid level wind shift certainly remain under the gun for
additional precipitation and have retained moderate POPs across all
but far NW MO for that reason.
.LONG TERM...(Saturday through Wednesday)
Issued at 322 AM CDT THU AUG 8 2013
The upcoming weekend should remain dry as the region will fall under
the influence of high pressure moving southeast through the Great
Lakes. With little change in the synoptic pattern and a continuance
of progressive zonal to northwesterly flow heading into into next
week, it appears there will only be a short break to the rainfall in
the region. By Monday, upper troughing will temporarily deepen over
Manitoba and Ontario, pushing a weak shortwave into the Central
Plains. Increasing warm advection ahead of this wave will induce
showers and thunderstorms over a large area of the central CONUS
Monday into Monday night. Have increased PoPs from late Sunday
night into Tuesday morning.
Latest guidance suggests a cold front will sweep southward through
the region by Tuesday morning, with high pressure once again moving
into the western Great Lakes providing dry conditions to the local
area.
As far as temperatures are concerned, warm advection and
southwesterly surface flow on Sunday will push temperatures back
towards seasonal normals. However, past the frontal passage on
Tuesday, temperatures will likely remain below normal into the
middle of next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1153 PM CDT WED AUG 7 2013
VFR conditions are expected through the entire forecast. There may be
a brief period around sunrise of minor fog or haze reducing
visibilities to around 4 miles or so. Have kept this out of the
forecast for now as winds around 5 knots from the north to northeast
should keep the lowest levels mixed enough to prevent much fog
formation. Otherwise, only mid to high level clouds are expected with
winds becoming more easterly tomorrow but still remaining light. any
chances for storms should remain to the south for the rest of the
overnight. A dying area of showers or storms is possible by late
morning but the dry air in the lowest levels may kill things off
before getting to the terminals.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...CDB
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
330 AM MDT THU AUG 8 2013
.DISCUSSION...
SURFACE BOUNDARY ATTM IN APPROXIMATELY THE SAME LOCATION AS ONE 24
HOURS. STILL CONSIDERABLE MOISTURE LINGERING OVER THE STATE WITH
SIGNIFICANTLY DRIER DEWPOINTS AS WELL AS A MUCH DRIER AIR MASS
OVERALL ACROSS CENTRAL/WRN AZ. SOMEWHAT MORE ORGANIZED CLOUD COVER
ROTG SE OVER THE FOUR CORNERS REGION...AND RUC13 CONTINUES TO
ANALYZE A WEAK CLOSED CIRCULATION AT H5 OVER NW NM/SW CO THROUGH
EARLY THIS AFTERNOON. AS THE DAY PROGRESSES...A SURFACE BOUNDARY IS
FORECAST TO BECOME MORE DEFINED OVER NE NM. THEREFORE HAVE TRENDED
TOWARDS THE HIGHER GUIDANCE POPS TODAY FOR THE NORTHEAST THIRD TO
HALF OF THE FORECAST AREA. LATEST SPC OUTLOOK HAS SLIGHT RISK FOR
SVR STORMS IN AN AREA SIMILAR TO WHAT WAS PREDICTED 24 HOURS AGO.
HAVE NOT HIGHLIGHTED THAT POSSIBILITY IN THE WX GRIDS...SO LATER
SHIFTS WILL NEED TO MONITOR.
FRONT TO PLUNGE INTO THE EASTERN PLAINS TONIGHT BUT NOT MUCH
INDICATION MODEL WISE IT WILL REACH THE RGV. FRIDAY NIGHT APPEARS AS
IF THIS POSSIBILITY IS MORE LIKELY...TRENDING SHOWER AND STORM
CHANCES UPWARD AND WESTWARD. HIGHS TODAY WILL BE A FEW DEGREES
BELOW AVERAGE MAINLY NORTH OF INTERSTATE 40...AND MAINLY OVER THE
NORTHEAST QUARTER FRIDAY. WITH POTENTIAL FORECAST FOR A MONSOON
BURST...HIGHS SATURDAY ACROSS THE NORTHWEST HALF WILL BE SEVERAL
DEGREES BELOW AVERAGE.
ANOTHER TRANSITION FORECAST IN THE WEATHER PATTERN FOR NEXT
WEEK...WITH A TREND TOWARDS WARMER AND DRIER. THE UPPER HIGH CENTER
DRIFTS BACK OVER NEW MEXICO...AND FAR ENOUGH WESTWARD TO PUT THE
NORTHEAST UNDER NORTHWEST FLOW AS LEAST FOR A DAY OR TWO.
&&
.FIRE WEATHER...
BACK DOOR COLD FRONT HAS MOVED INTO THE EASTERN PLAINS WITH A
REINFORCEMENT OF THIS BOUNDARY EXPECTED FRIDAY NIGHT. CURRENTLY THE
REMNANTS OF THE UPPER LOW FROM AZ CONTINUE TO BECOME LESS ORGANIZED
OVER SOUTHERN CO. MOISTURE AND LINGERING ENERGY FROM THE LEFTOVER
DISTURBANCE WILL KEEP THE BEST WETTING RAIN CHANCES OVER NORTH
CENTRAL TO NORTHEASTERN NM TODAY. MODELS CONTINUE TO ADVERTISE DRIER
AIR WORKING IN FROM THE WEST TODAY...AND WATER VAPOR SATELLITE
IMAGERY SUPPORTS THIS. THEREFORE...EXPECT MINIMAL SHOWER/STORM
COVERAGE IN THE CENTRAL TO WEST CENTRAL AND NORTHWESTERN ZONES
TODAY. MINIMUM RH WILL STILL STAY AOA 20 PERCENT WITH MODERATE
SURFACE BREEZES EXHIBITING A NORTHWESTERLY COMPONENT OVER MUCH OF
THE FORECAST AREA. EXCELLENT RH RECOVERY IS EXPECTED OVER THE
NORTHEASTERN HALF OF THE FORECAST AREA TONIGHT WITH STILL GOOD
RECOVERY OF 60-80 PERCENT FARTHER WEST. CONVECTION FROM THE LATE
EVENING MAY ATTEMPT TO SHOVE AN EAST WIND BEYOND THE CENTRAL
MOUNTAIN CHAIN TONIGHT...BUT MODELS ARE NOT ENTHUSIASTIC ABOUT IT.
AT THIS TIME NO STRONG GAP/CANYON WINDS HAVE BEEN BUILT INTO THE
FORECAST THROUGH FRIDAY MORNING.
MOISTURE WILL HAVE AT LEAST WORKED TOWARD THE CENTRAL MOUNTAIN CHAIN
EARLY ON FRIDAY WITH THE AFOREMENTIONED EASTERLY WINDS...AND THIS
MOISTURE PUSH WILL CONTINUE WESTWARD INTO THE AFTERNOON. STORMS WILL
BECOME A BIT MORE WIDESPREAD ALONG THE CENTRAL MOUNTAIN CHAIN AND
TOWARD THE CONTINENTAL DIVIDE AS TEMPERATURES WARM CLOSE TO AVERAGE
IN MOST ZONES. LOWEST MINIMUM RH VALUES WILL BE IN THE SAN JUAN
BASIN FRIDAY WHERE VALUES WILL SLIP TO 20 PERCENT OR JUST SLIGHTLY
BELOW. ANY CONVECTION LATE FRIDAY EAST OF THE CENTRAL MOUNTAINS WILL
AID THE PUSH OF A REINFORCING BACK DOOR FRONT. THIS WILL CONTINUE TO
CARRY MOISTURE WESTWARD WHILE ALSO PRODUCING MODERATE TO STRONG
GAP/CANYON WINDS NEAR CENTRAL VALLEY LOCATIONS THROUGH SATURDAY
MORNING.
BETTER LOW LAYER MOISTURE TRANSPORTED FROM THE EAST WILL COUPLE WITH
A MID LEVEL MONSOON PLUME SQUEEZING INTO NM...AND THIS WILL SET THE
STAGE FOR AN ACTIVE THUNDERSTORM DAY SATURDAY. NAM MODEL IS MOST
BULLISH WITH WETTING PRECIP CHANCES AND CONSEQUENTLY BOASTS MUCH
COOLER TEMPERATURES WHICH WOULD CERTAINLY MITIGATE ANY FIRE WX
CONCERNS. PLENTY OF LEFTOVER MOISTURE TO RECYCLE ON SUNDAY WILL ALSO
YIELD A GOOD CROP OF STORMS. INTO NEXT WEEK THE UPPER HIGH IS STILL
DEPICTED AS MOVING WESTWARD OVER OR CLOSE TO NM WHILE ELONGATING
SOME ON A WEST-EAST AXIS. ANOTHER BACK DOOR FRONT IN THE NORTHEAST
COULD KEEP CONVECTIVE ACTIVITY GOING IN THE NORTHEAST LATE TUESDAY.
52
&&
.AVIATION...
06Z TAF CYCLE
SH/TS ACTIVITY ASSOCIATED WITH THE UPPER LOW HAS BEEN WINDING DOWN
THE PAST FEW HOURS. BACK DOOR COLD FRONT HAS SPILLED INTO THE
NORTHEAST AND EAST CENTRAL PLAINS. A FEW SHOWERS WILL LINGER WITH
THIS FRONT AS BEING THE FOCUS. THE FRONT SHOULD PUSH FURTHER
SOUTH. HAVE IT NOW IMPACTING ROW LATER TONIGHT. SHALL SEE ON
THAT. OTHERWISE...THE NORTHEAST WIND SHIFT HAS ALREADY OCCURRED AT
LVS AND TCC. ANOTHER ROUND OF SH/TS WITH MTN TOP OBSCD EXPECTED
ACROSS THE NORTHERN THIRD OR SO OF THE FORECAST AREA THURSDAY
AFTERNOON. USING VCSH FOR A PLACEHOLDER AT FMN/SAF AND LVS. THESE
SITES ARE THE MOST LIKELY TO RECEIVE SOME SORT OF EFFECT FROM A
PASSING SH OR TS BASED ON STEERING FLOW CONSIDERATIONS.
50
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 85 56 89 59 / 20 10 20 40
DULCE........................... 77 47 84 50 / 40 20 30 40
CUBA............................ 79 51 82 52 / 30 10 20 40
GALLUP.......................... 82 47 85 54 / 10 10 20 20
EL MORRO........................ 79 46 82 51 / 10 10 30 30
GRANTS.......................... 82 49 85 54 / 10 10 30 30
QUEMADO......................... 82 51 85 55 / 10 10 20 30
GLENWOOD........................ 86 57 90 58 / 10 10 20 20
CHAMA........................... 73 43 78 47 / 50 20 30 50
LOS ALAMOS...................... 78 53 81 56 / 40 10 30 40
PECOS........................... 79 52 78 53 / 50 20 30 50
CERRO/QUESTA.................... 76 46 78 49 / 60 30 30 40
RED RIVER....................... 67 43 71 43 / 60 40 50 50
ANGEL FIRE...................... 71 44 75 47 / 60 30 50 50
TAOS............................ 77 47 80 51 / 50 20 20 40
MORA............................ 73 48 75 49 / 50 30 40 50
ESPANOLA........................ 85 53 86 55 / 30 20 20 40
SANTA FE........................ 81 53 82 54 / 40 20 30 40
SANTA FE AIRPORT................ 84 55 85 56 / 30 20 20 40
ALBUQUERQUE FOOTHILLS........... 85 61 87 64 / 10 10 20 40
ALBUQUERQUE HEIGHTS............. 87 64 89 66 / 10 10 20 30
ALBUQUERQUE VALLEY.............. 88 59 90 62 / 10 10 20 20
ALBUQUERQUE WEST MESA........... 87 61 90 62 / 10 10 20 40
LOS LUNAS....................... 89 62 92 63 / 10 10 20 20
RIO RANCHO...................... 87 64 89 64 / 10 10 20 40
SOCORRO......................... 92 66 93 65 / 10 10 20 20
SANDIA PARK/CEDAR CREST......... 84 57 85 59 / 20 10 30 40
TIJERAS......................... 85 60 86 62 / 20 10 30 40
MORIARTY/ESTANCIA............... 85 54 83 57 / 30 20 30 40
CLINES CORNERS.................. 82 55 80 56 / 40 20 30 40
GRAN QUIVIRA.................... 85 56 85 57 / 20 10 20 40
CARRIZOZO....................... 87 61 88 62 / 10 10 20 30
RUIDOSO......................... 79 59 79 57 / 10 20 30 40
CAPULIN......................... 74 50 76 51 / 60 30 30 30
RATON........................... 77 52 79 53 / 50 30 30 30
SPRINGER........................ 78 51 78 52 / 50 30 30 30
LAS VEGAS....................... 80 50 78 52 / 50 20 30 40
CLAYTON......................... 79 57 82 57 / 50 30 20 20
ROY............................. 80 54 81 56 / 50 30 20 30
CONCHAS......................... 85 60 86 61 / 40 20 20 40
SANTA ROSA...................... 86 62 87 63 / 30 20 20 40
TUCUMCARI....................... 90 63 89 64 / 30 20 20 40
CLOVIS.......................... 91 62 87 62 / 30 20 20 40
PORTALES........................ 92 63 88 63 / 30 20 20 40
FORT SUMNER..................... 95 64 90 65 / 20 20 20 40
ROSWELL......................... 97 69 95 69 / 10 20 20 50
PICACHO......................... 88 63 89 62 / 10 20 30 40
ELK............................. 81 61 84 59 / 10 20 40 50
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
405 AM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTENROON WITH SPOTTY ACTIVITY IN OUR ARAE. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
4 AM UPDATE...
VERY FEW CHANGES MADE TO INHERITED GRIDS AS GOOD AGREEMENT BETWEEN
THE GFS AND ECMWF SUPPORTS BETTER THAN AVERAGE CONFIDENCE THROUGH
THE PERIOD. UPPER PATTERN THROUGH THE TIME FRAME WILL BE DOMINATED
BY BROAD CYCLONIC FLOW ALOFT AS A BLOCKY MID-LATITUDE PATTERN
PERSISTS THANKS TO STRONG HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC
AND CANADIAN PRAIRIE PROVINCES. BOTH THE GFS AND ECMWF AGREE THAT A
SECOND UPPER LOW WILL SWING SOUTH FROM HUDSON BAY BY LATE MON/EARLY
TUESDAY WHICH WILL SEND A COLD FRONT EAST ACROSS OUR REGION AS LOW
PRESSURE TRACKS JUST OFF TO OUR NORTH. THUS EXPECT RENEWED SHWR AND
THUNDERSTORM CHANCES BY TUESDAY BEFORE DRY WX RETURNS TO CONCLUDE
THE PERIOD. BELOW NORMAL TEMPS EXPECTED WITH NO HINTS OF ANY MAJOR
WARMING SEEN FOR THE FORESEEABLE FUTURE.
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO
SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND
POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH
MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
VERY DIFFICULT FCST THIS MORNING AS LATEST SATELLITE AND
OBSERVATION TRENDS HAVE SHOWN A NOTABLE DECREASE IN LOW STRATUS
ACROSS THE REGION OVER THE PAST FEW HRS. ADDITIONALLY...CONVECTION
NOW ENTERING THE GREATER BUFFALO METRO WILL CONTINUE WORKING EAST
OVERNIGHT WITH POSSIBLE IMPACTS AT BOTH ELM AND ITH BY 10Z OR SO.
THAT SAID...HAVE DELAYED IFR MENTION AT BGM FOR A FEW HRS BASED ON
LATEST TRENDS...HOWEVER CONCERNS ARE THAT LOW CLOUDS WILL FILL
BACK IN AS WE PROGRESS THROUGH THE EARLY MORNING. IF THIS DOES
OCCUR...WE MAINLY EXPECT MVFR CONDITIONS AT REMAINING FCST LOCATIONS.
AFTER 12Z...FCST BECOMES MORE CLOUDED AS WEAK TO MODERATE
INSTABILITY DEVELOPS OVER THE REGION. ITS NEARLY IMPOSSIBLE TO
DISCERN ANY SPECIFIC TIMING AS THERE REMAINS VERY LITTLE IN THE
WAY OF ANY APPRECIABLE FORCING MECHANISMS. FOR NOW...WILL CONTINUE
WITH EARLIER LINE OF THINKING WITH POSSIBLE SHWRS/STORMS
DEVELOPING ALONG AND EAST OF THE I-81 CORRIDOR LATER THIS AFTERNOON.
RAIN TO LIKELY CONTINUE INTO THE EVENING HRS...ESPECIALLY AT AVP
AS NEXT SFC WAVE WORKS NORTH WITH TIME.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...
SHORT TERM...JAB
LONG TERM...BMW/CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
341 AM EDT THU AUG 8 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1223 AM EDT THURSDAY...CURRENT FORECAST IN GREAT SHAPE AND
ONLY MINOR ADJUSTMENTS TO T/TD/MIN TEMP DATASETS AS OF THE
MIDNIGHT HOUR. SCT CONVECTION ALONG PRE-FRONTAL TROUGH HAVING A
HARD TIME MAKING IT INTO OUR REGION AND TRUDGING SLOWLY EAST FROM
ONTARIO/OTTAWA VALLEY ATTM. INDEED...LATEST CAM MODEL RUNS
ACTUALLY SHOWING MUCH OF THIS ACTIVITY EITHER WANING OR SPLITTING
NORTH AND/OR SOUTH OF OUR AREA OVERNIGHT LEAVING MANY AREAS DRY.
THUS PRIOR IDEA OF LOWERING POPS TO CHANCE (30/40 PCT) LOOKS RIGHT
ON TRACK. TEMPERATURES WILL REMAIN MILD AND HOLD GENERALLY IN THE
60S TO LOCALLY NEAR 70 IN THE CHAMPLAIN VALLEY AS LIGHT TO
MODERATE SOUTH FLOW CONTINUES. HAVE A GREAT NIGHT. PRIOR
DISCUSSION FOLLOWS...
BASED ON CURRENT RADAR AND RECENT NAM/RAP/HRRR GUIDANCE TRENDS
HAVE MADE FAIRLY SIGNIFICANT DOWNWARD TWEAKS TO POPS TONIGHT INTO
THURSDAY MORNING. ASIDE FOR SOME SHOWERS THAT HAD MOVED ACROSS THE
NORTHERN CHAMPLAIN VALLEY INTO NORTHERN VERMONT...STEADIER/HEAVIER
SHOWERS AND THUNDERSTORMS REMAIN ACROSS EASTERN ONTARIO AND THE
NORTHERN SHORE OF LAKE ONTARIO. THE RADAR RETURNS ACROSS THE SAINT
LAWRENCE VALLEY ARE MERELY ANVIL SHADOWS...AND RECENT TRENDS SHOW
BETTER CONVECTIVE DEVELOPMENT TRAILING BACK ALONG THE NORTHERN
SHORE OF LAKE ONTARIO IN THE VICINITY OF THE TORONTO AREA. AS
MENTIONED...FEEL THAT THE NAM...RAP AND HRRR MODELS ARE CURRENTLY
HANDLING PRESENT CONDITIONS THE BEST AND HAVE THEREFORE ALIGNED
THE FORECAST CLOSER TO THAT SUITE OF GUIDANCE. SPECULATING THAT
OTHER WETTER GUIDANCE...E.G. THE GFS...MAY HAVE BEEN KEYING ON
DEEPER MOISTURE FEED WHICH THE EARLIER MCS OVER PA MAY HAVE TAPPED
INTO. NEVERTHELESS...STILL EXPECT SFC COLD FRONT ACROSS ONTARIO TO
APPROACH THE NORTH COUNTRY THROUGH OVERNIGHT BUT WILL ONLY BE
GOING WITH CHANCE TO HIGH CHANCE POPS THROUGH SUNRISE...AND THEN
SLIGHT CHANCE TO CHANCE THROUGH THE THURSDAY MORNING PERIOD.
CURRENT TEMPS/DEWPOINTS STILL LOOK ON TRACK AND IT SHOULD
OTHERWISE BE A CLOUDY...MILDER AND SLIGHTLY MORE HUMID NIGHT THAN
RECENTLY WITH LOWS IN THE UPPER 50S TO THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 341 AM EDT THURSDAY...ELONGATED AREA OF SFC HIGH PRESSURE
STRETCHING FROM THE GREAT LKS REGION TO THE EAST COAST FOR THE
SAT NGT-MONDAY MORNING PERIOD W/ END RESULT OF RIDGE SHIFTING
OFFSHORE THRU THE DAY MONDAY. EXPECTING NICE STRETCH OF WX OVER
THE UPCOMING WEEKEND AS A RESULT. THE NORTH COUNTRY WILL FEEL THE
EFFECTS OF BROAD UPPER LOW OVER EASTERN CANADA. ANOTHER LOW
PINWHEELING AROUND THIS SYSTEM WILL DIVE SE THRU THE GREAT LKS
MONDAY AND ACROSS THE NORTHEAST REGION INTO MIDWEEK. ZONAL
MIDLEVEL FLOW COMBINED WITH SOUTHERLY WINDS AT THE SFC...WILL
ALLOW FOR SLOW MVMNT THRU AREA AND WILL BRING AMPLE POTENTIAL QPF
AS A RESULT OF SSW FLOW. WILL BE CARRYING -RW FOR THE LATTER
PORTION OF EXTENDED INTO EARLY TUESDAY EVENING BFR SFC RIDGE
RETURNS FROM THE WEST DRYING REGION OUT AGAIN WED INTO THURS.
TEMPS NEAR NORMAL THRU PERIOD WITH HIGHS RANGING IN THE MID TO
UPPER 70S AND LOWS IN THE 40S TO L50S. PRECIP/CLD COVER MONDAY NGT
INTO TUESDAY COULD HAMPER TEMPS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
THROUGH 06Z FRIDAY...SCT -RW WITH SOME POSSIBLE FG THRU 12Z
THURSDAY WILL BRING MVFR COND WITH VSBY DOWN TO 3-6SM AT TIMES AND
CEILINGS DOWN TO BKN025-030 AT TIMES. FROM 12Z THURSDAY VFR
CONDITIONS WITH CEILINGS BKN040-060 AND VCSH. CHANCE FOR TRW TO
DEVELOP LATE IN AFTNOON INTO EVENING HRS. AFT 00Z FRI...SOME MVFR
FG FOR SLK/MPV ALONG WITH CHANCE FOR RW/TRW AS BOUNDARY PUSHES
THRU REGION. WINDS SSW 10-20KTS WITH GUSTS NEAR 30KTS FOR BTV.
LGT/VAR FOR MPV/SLK AFT 00Z FRI.
OUTLOOK 06Z FRIDAY THROUGH MONDAY...
06Z FRIDAY THROUGH 00Z SATURDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
00Z SATURDAY THROUGH MONDAY...MAINLY VFR UNDER SURFACE HIGH PRESSURE.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG/LOCONTO
SHORT TERM...WGH
LONG TERM...JN
AVIATION...LAHIFF/JN
MARINE...BTV
EQUIPMENT...BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
139 AM EDT THU AUG 8 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1223 AM EDT THURSDAY...CURRENT FORECAST IN GREAT SHAPE AND
ONLY MINOR ADJUSTMENTS TO T/TD/MIN TEMP DATASETS AS OF THE
MIDNIGHT HOUR. SCT CONVECTION ALONG PRE-FRONTAL TROUGH HAVING A
HARD TIME MAKING IT INTO OUR REGION AND TRUDGING SLOWLY EAST FROM
ONTARIO/OTTAWA VALLEY ATTM. INDEED...LATEST CAM MODEL RUNS
ACTUALLY SHOWING MUCH OF THIS ACTIVITY EITHER WANING OR SPLITTING
NORTH AND/OR SOUTH OF OUR AREA OVERNIGHT LEAVING MANY AREAS DRY.
THUS PRIOR IDEA OF LOWERING POPS TO CHANCE (30/40 PCT) LOOKS RIGHT
ON TRACK. TEMPERATURES WILL REMAIN MILD AND HOLD GENERALLY IN THE
60S TO LOCALLY NEAR 70 IN THE CHAMPLAIN VALLEY AS LIGHT TO
MODERATE SOUTH FLOW CONTINUES. HAVE A GREAT NIGHT. PRIOR
DISCUSSION FOLLOWS...
BASED ON CURRENT RADAR AND RECENT NAM/RAP/HRRR GUIDANCE TRENDS
HAVE MADE FAIRLY SIGNIFICANT DOWNWARD TWEAKS TO POPS TONIGHT INTO
THURSDAY MORNING. ASIDE FOR SOME SHOWERS THAT HAD MOVED ACROSS THE
NORTHERN CHAMPLAIN VALLEY INTO NORTHERN VERMONT...STEADIER/HEAVIER
SHOWERS AND THUNDERSTORMS REMAIN ACROSS EASTERN ONTARIO AND THE
NORTHERN SHORE OF LAKE ONTARIO. THE RADAR RETURNS ACROSS THE SAINT
LAWRENCE VALLEY ARE MERELY ANVIL SHADOWS...AND RECENT TRENDS SHOW
BETTER CONVECTIVE DEVELOPMENT TRAILING BACK ALONG THE NORTHERN
SHORE OF LAKE ONTARIO IN THE VICINITY OF THE TORONTO AREA. AS
MENTIONED...FEEL THAT THE NAM...RAP AND HRRR MODELS ARE CURRENTLY
HANDLING PRESENT CONDITIONS THE BEST AND HAVE THEREFORE ALIGNED
THE FORECAST CLOSER TO THAT SUITE OF GUIDANCE. SPECULATING THAT
OTHER WETTER GUIDANCE...E.G. THE GFS...MAY HAVE BEEN KEYING ON
DEEPER MOISTURE FEED WHICH THE EARLIER MCS OVER PA MAY HAVE TAPPED
INTO. NEVERTHELESS...STILL EXPECT SFC COLD FRONT ACROSS ONTARIO TO
APPROACH THE NORTH COUNTRY THROUGH OVERNIGHT BUT WILL ONLY BE
GOING WITH CHANCE TO HIGH CHANCE POPS THROUGH SUNRISE...AND THEN
SLIGHT CHANCE TO CHANCE THROUGH THE THURSDAY MORNING PERIOD.
CURRENT TEMPS/DEWPOINTS STILL LOOK ON TRACK AND IT SHOULD
OTHERWISE BE A CLOUDY...MILDER AND SLIGHTLY MORE HUMID NIGHT THAN
RECENTLY WITH LOWS IN THE UPPER 50S TO THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 341 PM EDT WEDNESDAY...THE EXTENDED PORTION OF THE FORECAST
WILL FEATURE PRETTY QUIET AND COOL WEATHER...NO SIGNIFICANT
CHANCES FOR PRECIPITATION. UPPER LEVEL LOW LIFTS NORTHEAST AND
AWAY FROM THE NORTH COUNTRY SATURDAY AND A RIDGE OF SURFACE HIGH
PRESSURE BUILDS INTO THE AREA. MAINLY DRY WEATHER IS EXPECTED
FROM SATURDAY THROUGH MONDAY. A LOW PRESSURE SYSTEM PASSING NORTH
OF OUR REGION ON MONDAY NIGHT WILL BRING A CHANCE FOR SOME
SHOWERS...THOUGH BEST DYNAMICS REMAIN WELL NORTH OF OUR FORECAST
AREA. TUESDAY THROUGH WEDNESDAY WILL ALSO BE QUIET WITH ANOTHER
RIDGE OF HIGH PRESSURE BUILDING INTO THE AREA.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THROUGH 06Z FRIDAY...SCT -RW WITH SOME POSSIBLE FG THRU 12Z
THURSDAY WILL BRING MVFR COND WITH VSBY DOWN TO 3-6SM AT TIMES AND
CEILINGS DOWN TO BKN025-030 AT TIMES. FROM 12Z THURSDAY VFR
CONDITIONS WITH CEILINGS BKN040-060 AND VCSH. CHANCE FOR TRW TO
DEVELOP LATE IN AFTNOON INTO EVENING HRS. AFT 00Z FRI...SOME MVFR
FG FOR SLK/MPV ALONG WITH CHANCE FOR RW/TRW AS BOUNDARY PUSHES
THRU REGION. WINDS SSW 10-20KTS WITH GUSTS NEAR 30KTS FOR BTV.
LGT/VAR FOR MPV/SLK AFT 00Z FRI.
OUTLOOK 06Z FRIDAY THROUGH MONDAY...
06Z FRIDAY THROUGH 00Z SATURDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
00Z SATURDAY THROUGH MONDAY...MAINLY VFR UNDER SURFACE HIGH PRESSURE.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG/LOCONTO
SHORT TERM...WGH
LONG TERM...NEILES
AVIATION...LAHIFF/JN
MARINE...BTV
EQUIPMENT...BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1223 AM EDT THU AUG 8 2013
.SYNOPSIS...
SOUTHERLY FLOW WILL PERSIST ACROSS THE NORTH COUNTRY OVERNIGHT
THROUGH THURSDAY WITH A CHANCE OF RAIN SHOWERS OVERNIGHT AND A
CHANCE OF SHOWERS AND THUNDERSTORMS ON THURSDAY. A COLD FRONT WILL
MOVE INTO THE REGION ON FRIDAY BRINGING MORE SHOWERS AND THUNDERSTORMS
TO THE NORTH COUNTRY. SOME THUNDERSTORMS ON FRIDAY COULD PRODUCE
LOCALLY HEAVY RAINFALL. A RIDGE OF HIGH PRESSURE WILL BUILD INTO
THE NORTH COUNTRY ON FRIDAY NIGHT AND WILL BRING FAIR AND DRY
WEATHER TO THE REGION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1223 AM EDT THURSDAY...CURRENT FORECAST IN GREAT SHAPE AND
ONLY MINOR ADJUSTMENTS TO T/TD/MIN TEMP DATASETS AS OF THE
MIDNIGHT HOUR. SCT CONVECTION ALONG PRE-FRONTAL TROUGH HAVING A
HARD TIME MAKING IT INTO OUR REGION AND TRUDGING SLOWLY EAST FROM
ONTARIO/OTTAWA VALLEY ATTM. INDEED...LATEST CAM MODEL RUNS
ACTUALLY SHOWING MUCH OF THIS ACTIVITY EITHER WANING OR SPLITTING
NORTH AND/OR SOUTH OF OUR AREA OVERNIGHT LEAVING MANY AREAS DRY.
THUS PRIOR IDEA OF LOWERING POPS TO CHANCE (30/40 PCT) LOOKS RIGHT
ON TRACK. TEMPERATURES WILL REMAIN MILD AND HOLD GENERALLY IN THE
60S TO LOCALLY NEAR 70 IN THE CHAMPLAIN VALLEY AS LIGHT TO
MODERATE SOUTH FLOW CONTINUES. HAVE A GREAT NIGHT. PRIOR
DISCUSSION FOLLOWS...
BASED ON CURRENT RADAR AND RECENT NAM/RAP/HRRR GUIDANCE TRENDS
HAVE MADE FAIRLY SIGNIFICANT DOWNWARD TWEAKS TO POPS TONIGHT INTO
THURSDAY MORNING. ASIDE FOR SOME SHOWERS THAT HAD MOVED ACROSS THE
NORTHERN CHAMPLAIN VALLEY INTO NORTHERN VERMONT...STEADIER/HEAVIER
SHOWERS AND THUNDERSTORMS REMAIN ACROSS EASTERN ONTARIO AND THE
NORTHERN SHORE OF LAKE ONTARIO. THE RADAR RETURNS ACROSS THE SAINT
LAWRENCE VALLEY ARE MERELY ANVIL SHADOWS...AND RECENT TRENDS SHOW
BETTER CONVECTIVE DEVELOPMENT TRAILING BACK ALONG THE NORTHERN
SHORE OF LAKE ONTARIO IN THE VICINITY OF THE TORONTO AREA. AS
MENTIONED...FEEL THAT THE NAM...RAP AND HRRR MODELS ARE CURRENTLY
HANDLING PRESENT CONDITIONS THE BEST AND HAVE THEREFORE ALIGNED
THE FORECAST CLOSER TO THAT SUITE OF GUIDANCE. SPECULATING THAT
OTHER WETTER GUIDANCE...E.G. THE GFS...MAY HAVE BEEN KEYING ON
DEEPER MOISTURE FEED WHICH THE EARLIER MCS OVER PA MAY HAVE TAPPED
INTO. NEVERTHELESS...STILL EXPECT SFC COLD FRONT ACROSS ONTARIO TO
APPROACH THE NORTH COUNTRY THROUGH OVERNIGHT BUT WILL ONLY BE
GOING WITH CHANCE TO HIGH CHANCE POPS THROUGH SUNRISE...AND THEN
SLIGHT CHANCE TO CHANCE THROUGH THE THURSDAY MORNING PERIOD.
CURRENT TEMPS/DEWPOINTS STILL LOOK ON TRACK AND IT SHOULD
OTHERWISE BE A CLOUDY...MILDER AND SLIGHTLY MORE HUMID NIGHT THAN
RECENTLY WITH LOWS IN THE UPPER 50S TO THE 60S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
AS OF 428 PM EDT WEDNESDAY...ON THURSDAY MODELS SHOW MOISTURE
STREAMING NORTHEASTWARD INTO THE REGION FROM THE OHIO VALLEY.
CONDITIONS DESTABILIZE DURING THE DAY ON THURSDAY...SO HAVE GONE
WITH LIKELY POPS FOR SHOWERS AND THUNDERSTORMS. EXPECTING THIS
ACTIVITY TO CONTINUE INTO THURSDAY NIGHT. MOISTURE WILL CONTINUE
TO STREAM INTO THE REGION ON FRIDAY WITH PRECIPITABLE WATER VALUES
APPROACHING 2 INCHES. HAVE ADDED ENHANCED WORDING TO THE FORECAST
TO MENTION LOCALLY HEAVY RAINFALL POSSIBLE ON FRIDAY. A COLD FRONT
WILL MOVE THROUGH THE REGION DURING THE DAY ON FRIDAY. DRIER AIR
WORKING INTO THE REGION FRIDAY NIGHT AFTER THE COLD FRONTAL
PASSAGE. EXPECTING SHOWER AND THUNDERSTORM ACTIVITY TO DIMINISH
EARLY FRIDAY EVENING.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 341 PM EDT WEDNESDAY...THE EXTENDED PORTION OF THE FORECAST
WILL FEATURE PRETTY QUIET AND COOL WEATHER...NO SIGNIFICANT
CHANCES FOR PRECIPITATION. UPPER LEVEL LOW LIFTS NORTHEAST AND
AWAY FROM THE NORTH COUNTRY SATURDAY AND A RIDGE OF SURFACE HIGH
PRESSURE BUILDS INTO THE AREA. MAINLY DRY WEATHER IS EXPECTED
FROM SATURDAY THROUGH MONDAY. A LOW PRESSURE SYSTEM PASSING NORTH
OF OUR REGION ON MONDAY NIGHT WILL BRING A CHANCE FOR SOME
SHOWERS...THOUGH BEST DYNAMICS REMAIN WELL NORTH OF OUR FORECAST
AREA. TUESDAY THROUGH WEDNESDAY WILL ALSO BE QUIET WITH ANOTHER
RIDGE OF HIGH PRESSURE BUILDING INTO THE AREA.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
THROUGH 00Z FRIDAY...DIFFICULT AVIATION FORECAST OVER THE NEXT 24
HOURS AS MOST MODELS NOT HANDLING THE CURRENT CONDITIONS VERY
WELL. BROKEN LINE OF SHOWERS/STORMS ENTERING THE OTTAWA RIVER
VALLEY ASSOCIATED WITH A PRE-FRONTAL SURFACE TROUGH WILL SHIFT
EAST INTO THE NORTH COUNTRY OVERNIGHT WHILE DISSIPATING. HAVE PUT
IN SOME VCTS FOR KMSS/KSLK BUT ONLY VCSH EASTWARD AS INSTABILITY
WEAKENS BY THE TIME PRECIP GETS THERE. SCATTERED SHOWERS PERSIST
THROUGH 09-12Z ALONG WITH SOME MVFR CIGS...THEN DISSIPATE FOR THE
MORNING HOURS AS THE REAL COLD FRONT BEGINS TO MOVE INTO THE SAINT
LAWRENCE VALLEY. MAINLY VFR CONDITIONS ARE THEN EXPECTED THURSDAY
WITH SCATTERED SHOWERS AND POSSIBLY STORMS ARE LIKELY AGAIN FROM
THE CHAMPLAIN VALLEY EAST DURING THE AFTERNOON...THOUGH DIFFICULT
TO FORECAST TIMING AND LOCATION SO HAVE JUST GONE WITH SOME MORE
VCSH. WINDS REMAIN MODERATE AT 5-10 KNOTS THROUGH THE PERIOD...
GUSTING A BIT THIS EVENING AND AGAIN TOMORROW AFTERNOON.
OUTLOOK 00Z FRIDAY THROUGH MONDAY...
00Z FRIDAY THROUGH 00Z SATURDAY...VFR WITH OCCASIONAL MVFR/IFR IN
SHOWERS/THUNDERSTORMS AS A WARM/OCCLUDED FRONT LIFTS ACROSS THE
AREA.
00Z SATURDAY THROUGH MONDAY...MAINLY VFR UNDER SURFACE HIGH PRESSURE.
&&
.MARINE...
A LAKE WIND ADVISORY IS IN EFFECT THROUGH EARLY THURSDAY MORNING. SOUTH
WINDS WILL INCREASE THIS EVENING TO 15 TO 25 KNOTS...PEAKING
AROUND MIDNIGHT WITH SOME GUSTS UP TO 30 KNOTS..ESPECIALLY ACROSS
THE OPEN WATERS OF CENTRAL AND NORTHERN LAKE CHAMPLAIN. WINDS
WILL GRADUALLY DECREASE TOWARDS THURSDAY MORNING WITH SOUTH WINDS
FROM 10 TO 20 KNOTS EXPECTED ON THURSDAY. THESE WINDS WILL CREATE
WAVES OF 2 TO 4 FEET ON THE BROAD LAKE...ESPECIALLY ACROSS THE
CENTRAL AND NORTHERN PORTIONS. WAVE HEIGHTS WILL DECREASE TO 1 TO
3 FEET FOR THURSDAY. IN ADDITION...SCATTERED SHOWERS AND POSSIBLE
THUNDERSTORMS MAY AFFECT THE AREA TONIGHT THROUGH THURSDAY...WITH
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS LIKELY LATE THURSDAY
NIGHT AND INTO FRIDAY.
&&
.EQUIPMENT...
AS OF 456 PM EDT WEDNESDAY...THE KTYX 88D DOPPLER RADAR IN
NORTHERN NEW YORK HAS BEEN RESTORED TO SERVICE. SOME ADDITIONAL
WORK ON THIS RADAR WILL NEED TO BE DONE ON THURSDAY.
AS OF 350 AM EDT WEDNESDAY...NOAA WEATHER RADIO STATION WXM 44...
BROADCASTING FROM THE TOP OF MOUNT ASCUTNEY VERMONT...REMAINS OFF
THE AIR UNTIL FURTHER NOTICE DUE TO A DAMAGED ANTENNA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG/LOCONTO
SHORT TERM...WGH
LONG TERM...NEILES
AVIATION...LAHIFF
MARINE...MUCCILLI
EQUIPMENT...BTV
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
320 AM EDT THU AUG 8 2013
.SYNOPSIS...
A GRADUAL TRANSITION TO WARMER TEMPERATURES AND INCREASED CHANCES
FOR RAIN WILL OCCUR THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM THURSDAY...AFTER ENJOYING SEVERAL DAYS OF BELOW-NORMAL
TEMPERATURES AND HUMIDITY...THE REALITY OF AUGUST RETURNS TO THE
CAROLINAS TODAY. THE SURFACE RIDGE AXIS THAT HELD OUR SURFACE WINDS
EASTERLY OVER THE PAST SEVERAL DAYS IS GONE. BERMUDA HIGH PRESSURE
WILL ESTABLISH A SOUTH FLOW ACROSS THE AREA TODAY WITH TEMPERATURES
RISING TO AROUND 90 INLAND AND UPPER 80S NEAR THE COAST.
WITH NO SUBSIDENCE INVERSIONS TO DEAL WITH TODAY AND SURFACE-BASED
CAPE BUILDING TO AROUND 1000 J/KG...LOOK FOR SCATTERED SHOWERS AND A
FEW T-STORMS TODAY AS WELL. ACTIVITY COULD GET A VERY EARLY START
ALONG THE COAST AND PARTICULARLY IN THE CAPE FEAR REGION WHERE THE
LAST SEVERAL RUNS OF THE HRRR INDICATE SHOWERS MAY DEVELOP AS EARLY
AS SUNRISE NEAR SOUTHPORT AND WILMINGTON. BY LATE MORNING SCATTERED
CONVECTION SHOULD BE LINING UP ALONG THE DEVELOPING SEABREEZE
BOUNDARY...LIFTING SLOWLY INLAND THROUGH THE AFTERNOON HOURS.
FORECAST POPS RANGE FROM 20-40 PERCENT...HIGHEST ACROSS SE NORTH
CAROLINA.
FOR TONIGHT...INLAND CONVECTIVE ACTIVITY SHOULD GRADUALLY DIMINISH
DURING THE EVENING HOURS WITH SKIES BECOMING MOSTLY CLEAR TO PARTLY
CLOUDY. SOME LOW STRATUS MAY DEVELOP VERY LATE TONIGHT INLAND AS
SATURATION OCCURS WITHIN THE BOUNDARY LAYER BUT 1000-FOOT WINDS
REMAIN A LITTLE TOO STRONG FOR FOG. LOWS WILL FALL TO 72-74 INLAND
AND 73-78 NEAR THE COAST. SOME SOUTH-FACING BEACHES COULD SEE LOW
TEMPERATURES STRUGGLE TO DROP BELOW 80 IF THE ONSHORE WIND CONTINUES
THROUGH THE NIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...MID LEVEL RIDGE WILL REMAIN ACROSS THE AREA AS A
WESTERLY PATTERN DEVELOPS AT THE MID LEVELS. HOWEVER THERE WILL BE
INTERVALS OF RICHER THETA-E AIR TRAVERSING THE ZONAL FLOW WHICH
WARRANTS AT LEAST LOW CHANCE POPS THROUGH THE PERIOD. THE NUMEROUS
CLUSTERS OF THUNDERSTORMS WE HAVE SEEN MOVING ACROSS THE TENNESSEE
VALLEY WILL NOW TAKE AIM ON THE CAROLINAS. THE PIEDMONT TROUGH WILL
BE ENHANCED WITH THE WESTERLY FLOW WHICH WILL ASSIST IN THE FORCING
AS WELL. I HAVE MAINTAINED THE CHANCE POPS...MAINLY ON A DIURNAL
BASIS THROUGH THE PERIOD. AS WE GET CLOSER TO THE WEEKEND...THERE
WILL BE TIMES WHEN LIKELY POPS WILL BE WARRANTED BUT THIS WILL BE
BETTER ADDRESSED WITH THE NEAR TERM FORECAST. TEMPERATURE TRENDS
REMAIN RELATIVELY UNCHANGED WITH THE STRONG RIDGE AND DOWNSLOPE
COMPONENT LEADING TO READINGS SLIGHTLY ABOVE CLIMATOLOGY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...MEDIUM RANGE GUIDANCE IS TRENDING TOWARD A
RATHER WET SCENARIO FOR THE EXTENDED PERIOD. ELONGATED MID LEVEL
RIDGE SHIFTS WEST AND TROUGHING DEVELOPS ACROSS THE OHIO VALLEY.
THE TROUGH REMAINS IN PLACE AS DOES THE FRONT ASSOCIATED WITH
IT...WHICH IS POSITIONED RIGHT ACROSS OUR AREA. THIS WILL PROVIDE
A GOOF FOCUSING MECHANISM FOR INTERVALS OF SHOWERS AND
THUNDERSTORMS. HAVE INCREMENTALLY INCREASED POPS TO REPRESENT THIS
TREND. TEMPERATURES FORECAST IS ALREADY SHOWING LOWER THAN USUAL
DIURNAL RANGE WITH THE MOISTURE AND NEEDED NO CHANGES WITH THE
MORNING UPDATE.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...ISOLATED SHRA OVER THE ATLANTIC SHOULD REMAIN JUST EAST
OF THE ILM AIRPORT THROUGH DAYBREAK. ANTICIPATE DEVELOPMENT OF MVFR
CIGS ALONG THE COAST...WITH POSSIBLE IFR/LIFR INLAND DUE TO FOG &
LOW CIGS AN HOUR OR TWO BEFORE DAYBREAK. FLIGHT CATEGORY SHOULD
IMPROVE TO VFR NO LATER THAN 13-14Z. CANNOT RULE OUT ISOLATED
SHOWERS...THUS HAVE OPTED TO INTRODUCE VCSH AT ALL SITES...BEGINNING
ALONG THE COAST FIRST. SHOWERS WILL TAPER OFF IN THE EVENING HOURS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM THURSDAY...THE SURFACE RIDGE AXIS THAT HAS HELD OUR
WIND DIRECTIONS EASTERLY FOR THE PAST SEVERAL DAYS HAS FINALLY
BROKEN DOWN. RATHER THAN CANADIAN HIGH PRESSURE POKING DOWN FROM THE
NORTHEAST...OUR WEATHER TODAY AND TONIGHT WILL COME UNDER THE
INFLUENCE OF BERMUDA HIGH PRESSURE FROM THE EAST. THIS MEANS WINDS
WILL BECOME SOUTHERLY TODAY AND SOUTH-SOUTHWESTERLY TONIGHT...WITH
SPEEDS AVERAGING 10-12 KNOTS. SEAS ARE CURRENTLY 2-3 FT WITH PERIODS
SPLIT BETWEEN A 6 SECOND WIND WAVE AND A WEAK 9-10 SECOND SOUTHEAST
SWELL. SEAS MAY BUILD HALF A FOOT THROUGH TONIGHT AS SOUTH WINDS
FURTHER DEVELOP THE WIND WAVE COMPONENT.
RADAR CURRENTLY SHOWS ONLY ISOLATED SHOWERS OUT BEYOND 30 MILES FROM
SHORE...BUT MODELS ARE SHOWING WE SHOULD HAVE SCATTERED SHOWERS
DEVELOPING NEARSHORE NEAR AND NORTH OF CAPE FEAR THIS MORNING.
CONVECTIVE ACTIVITY SHOULD LARGELY SHIFT INLAND THIS AFTERNOON AS
THE SEABREEZE CIRCULATION BECOMES BETTER DEVELOPED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...ELEMENTS REMAIN THE SAME FOR THE COASTAL WATERS
THROUGH THE PERIOD AS BERMUDA HIGH PRESSURE AND THE PIEDMONT TROUGH
KEEP A SOUTHWESTERLY FLOW IN PLACE. SPEEDS REMAIN STABLE IN A RANGE
OF 10-15 KNOTS...WHICH IF ANYTHING MAY BE ON THE HIGHER END SATURDAY
AFTERNOON AS THE TROUGH STRENGTHENS. THE TEPID INCREASE IN WINDS
ISN/T ENOUGH TO IMPACT SIGNIFICANT SEAS...WHICH REMAIN IN A 2-3 FOOT
RANGE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...DIFFUSE FRONT WILL REMAIN JUST INLAND...AT LEAST
LOOKING AT THE LATEST WPC FORECAST AND THIS WILL KEEP A RATHER WEAK
SOUTHWESTERLY FLOW IN PLACE. SPEEDS CONTINUE TO HOVER AROUND TEN
KNOTS OR BELOW. CAN/T RULE OUT BRIEF DISRUPTIONS IN THE SYNOPTIC
FLOW WITH INTERVALS OF CONVECTION EXPECTED BUT THIS OF COURSE IS ALL
BUT IMPOSSIBLE TO FORECAST THIS FAR OUT IN TIME. SIGNIFICANT SEAS
SHOW LITTLE CHANGE AS WELL WITH 2-3 FEET AND LITTLE IN THE WAY OF A
SWELL COMPONENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1242 AM CDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1242 AM CDT THU AUG 8 2013
LINGERING ISOLATED LIGHT RAIN SHOWERS OVER SOUTH CENTRAL NORTH
DAKOTA WERE ASSOCIATED WITH WEAK UPPER LEVEL IMPULSES MOVING
SOUTHEASTWARD ACROSS THE STATE. CURRENT FORECAST ON TRACK
REGARDING THIS...AS WELL AS WINDS AND TEMPERATURES FOR THE
OVERNIGHT HOURS.
UPDATE ISSUED AT 903 PM CDT WED AUG 7 2013
MAIN UPDATE WAS TO REMOVE MENTION OF THUNDER FOR ALL BUT THE
SOUTHWEST UNTIL MIDNIGHT...THEN REMOVE THUNDER ALTOGETHER. LATEST
WATER VAPOR IMAGERY SHOWED A SHORTWAVE NOW OVER WESTERN NORTH
DAKOTA...WITH A NARROW BAND OF LIFT/RAIN SHOWERS SOUTH OF HIGHWAY
2...FROM NEAR NEW TOWN EAST TO HARVEY. THIS AREA WAS CONTINUING TO
SAG SOUTH WHILE CONTINUING TO ADVANCE EAST. LOCAL RADAR WAS ALSO
SHOWING A WEAK LINE OF SHOWERS EXTENDING FROM GARRISON SOUTH TO
BISMARCK. SPC MESO-ANALYSIS SHOWS MID LEVEL LAPSE RATES INCREASING
IN RESPONSE TO THE SHORTWAVE IN WESTERN NORTH DAKOTA. WITH 50KT
0-6KM SHEAR IN THE SOUTHWEST...WILL CONTINUE TO MENTION ISOLATED
THUNDERSTORMS. A LACK OF INSTABILITY ELSEWHERE WILL INHIBIT ANY
THREAT OF THUNDERSTORMS. THE RAP AND 00Z NAM MAINTAIN THE IDEA THAT
ISOLATED SHOWERS WILL CONTINUE TO PUSH SOUTH TO THE BORDER THROUGH
12Z THURSDAY. CONCUR WITH THIS IDEA BASED ON THE POSITION AND
MOVEMENT OF THE AFOREMENTIONED SHORTWAVE. MINOR UPDATES TO
POPS/SKY/WX AND HOURLY TEMPERATURES.
UPDATE ISSUED AT 542 PM CDT WED AUG 7 2013
LATEST WATER VAPOR IMAGERY SHOWS A SHORTWAVE NOW WORKING ITS WAY
INTO NORTHEAST MONTANA FROM SOUTHERN SASKATCHEWAN. AN AREA OF RAIN
SHOWERS CONTINUE TO MOVE INTO NORTHWEST NORTH DAKOTA. THE LATEST
RAP HAS A GOOD READ ON THE ACTIVITY AS SCOOTS IT ACROSS THE NORTH
CENTRAL THIS EVENING. IN ADDITION...WILL WATCH FOR SHOWERS TO
DEVELOP IN THE WEST AND SOUTH CENTRAL EARLY TONIGHT PER RAP MODEL.
RADAR SHOWING A WEAK LINE TRYING TO GENERATE FROM NEAR WILLISTON
SOUTH TO TROTTERS AT THIS MOMENT. BEST FORCING REMAINS NORTH. THUS
WILL CONTINUE WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS NORTH
THIS EVENING AND ISOLATED SHOWERS/THUNDERSTORMS WEST AND CENTRAL
OVERNIGHT. GIVEN THE WEAK INSTABILITY...THUNDER SHOULD REMAIN
ISOLATED. MINOR UPDATES TO HOURLY TEMPS/DEWPOINTS AND CHANGED
UNCERTAINTY WORDING TO AREAL COVERAGE IN THE WEATHER GROUP BASED
ON RADAR.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CURRENTLY...A STRONG UPPER LEVEL JET AND A SHORTWAVE IMPULSE
TRACKING ACROSS SOUTHERN SASKATCHEWAN IS RESPONSIBLE FOR PRODUCING
SCATTERED SHOWERS FROM NORTHEAST MONTANA INTO NORTHWEST NORTH
DAKOTA. THE SHOWERS ARE EXPECTED TO TRACK EAST AND SOUTH ACROSS
THE AREA LATE THIS AFTERNOON AND THIS EVENING. SIMILAR TO THE
TRACK OF A SHORTWAVE YESTERDAY. THE MAIN DIFFERENCE IS THE
ATMOSPHERE IS MORE STABLE TODAY. HOWEVER...WITH A STRONG UPPER
LEVEL JET AND SHORTWAVE...WE CANNOT RULE OUT A FEW THUNDERSTORMS
THIS AFTERNOON AND EARLY EVENING...WITH SMALL HAIL AND GUSTY
WINDS. HOWEVER IN THE FORECAST WE LIMITED THE BEST CHANCES TO THE
NORTH LATE THIS AFTERNOON...AND WITH LIMITED INSTABILITY AND
CAPPING ALOFT...WE KEPT A MENTION OF SHOWERS WITH ONLY ISOLATED
THUNDERSTORMS. EXPECT PRECIPITATION CHANCES TO DIMINISH AS THE
SYSTEM TRACKS SOUTHEAST. BUT THE LATEST RAP AND HRRR HOLD
REFLECTIVITIES TOGETHER AS THEY TRACK INTO THE SOUTHEAST CWA
AROUND MIDNIGHT.
MODELS HAVE TRENDED FARTHER SOUTH WITH THE NEXT WAVE COMING INTO
THE AREA AFTER MIDNIGHT. HAVE THEREFORE CONTINUED THE TREND OF
LOWERING POPS ACROSS THE AREA. CURRENTLY HAVE CHANCE POPS ACROSS
THE FAR SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT...AND HAVE
DROPPED POPS ACROSS THE SOUTH ON THURSDAY MORNING. ANOTHER
SHORTWAVE MOVING ACROSS ALBERTA TONIGHT WILL DROP SOUTHEAST INTO
THE LOCAL AREA THURSDAY AFTERNOON. THIS COULD DEVELOP AN ISOLATED
SHOWERS ACROSS THE NORTH DURING THE AFTERNOON. TEMPERATURES WILL
REMAIN ON THE COOL SIDE WITH HIGHS RANGING FROM THE 60S NORTH TO
THE 70S SOUTH.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 338 PM CDT WED AUG 7 2013
CONTINUED BELOW NORMAL TEMPERATURES WILL HIGHLIGHT THE EXTENDED
FORECAST.
AS HAS BEEN THE PATTERN OVER THE LAST COUPLE WEEKS...NORTHWEST
FLOW ALOFT WILL CONTINUE ACROSS THE NORTHERN PLAINS THROUGH THE
EXTENDED. THIS FAVORS BELOW NORMAL TEMPERATURES WITH HIGHS
GENERALLY IN THE 70S...PERHAPS RECOVERING INTO THE LOWER 80S BY
MID NEXT WEEK. OVERALL...THE COOLER EDGE OF GUIDANCE HAS BEEN
HANDLING THIS PATTERN BETTER...AND THUS UTILIZED A BLEND OF THE
BIAS CORRECTED 12 UTC SUITE. IN REGARDS TO PRECIPITATION...WHILE
ISOLATED DIURNAL CONVECTION IS HARD TO RULE OUT ANY DAY UNDER
NORTHWEST FLOW...THE FAVORED PERIODS FOR PRECIPITATION ARE SATURDAY
WITH LEE SURFACE LOW PRESSURE AND AGAIN TUESDAY INTO WEDNESDAY AS
PACIFIC ENERGY CRESTS THE UPPER LEVEL INTERMOUNTAIN WEST RIDGE AND
PROPAGATES INTO THE NORTHERN PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1242 AM CDT THU AUG 8 2013
SCT TO BKN VFR CIGS EXPECTED THROUGH THE TAF PERIOD. NOT MUCH
CHANGE IN SYNOPTIC PATTERN THIS 24 HOUR TIME PERIOD WITH SURFACE
HIGH PRESSURE IN CANADA PUSHING SOUTHWARD FARTHER INTO NORTH
DAKOTA...AND UPPER LEVEL DISTURBANCES IN THE NORTHWEST FLOW ALOFT.
LIGHT EAST TO NORTHERLY WINDS WITH NO MENTION OF PRECIPITATION
EXCEPT FOR AT KJMS EARLY IN THE TAF PERIOD WITH LINGERING LIGHT
SHOWERS OVER SOUTH CENTRAL NORTH DAKOTA UNTIL AROUND 12Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...JV
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
208 AM EDT THU AUG 8 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY PUSH INTO THE REGION TONIGHT AND THURSDAY.
THE FRONT WILL EVENTUALLY STALL CLOSE TO THE OHIO RIVER BY FRIDAY
MORNING. THIS FRONTAL BOUNDARY WILL THEN OSCILLATE NEAR THE OHIO
RIVER THROUGH THE WEEKEND. THE THREAT OF SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THE PERIOD...ESPECIALLY FOR THOSE LOCATIONS
CLOSER TO THE FRONTAL BOUNDARY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HAVE UPDATED PRIMARILY TO ACCOUNT FOR SHOWERS AND THUNDERSTORMS
OVER PORTIONS OF NORTHERN KENTUCKY SOUTH OF METRO CINCINNATI. A
WEAK INFLECTION RUNNING ALONG BUT JUST SOUTHEAST OF THE I-71
CORRIDOR MAY HAVE AN ENHANCED POTENTIAL FOR SHOWERS THIS EVENING
BUT ONLY FOR THE NEXT HOUR OR TWO. UPSTREAM STORMS OVER INDIANA DO
NOT POSE A THREAT TO US IN THE NEXT 3-5 HOURS AND THE STORMS OVER
KY WILL BE DYING OUT AS THEY SLOWLY MOVE ENE. BLENDED INTO THE
30ISH POPS TOWARDS DAYBREAK THAT WERE IN EARLIER FORECAST AND
TRIED TO PLAY DOWN THE THREAT ELSEWHERE...AT LEAST FOR THE EARLY
PART OF THE OVERNIGHT.
HAVE USED A BLEND OF THE HRRR AND NAM FOR THE NEAR TERM FORECAST.
A COLD FRONT WAS POISED TO OUR NORTHWEST THIS EVENING. THIS FRONT
IS FORECAST TO SLOWLY SINK SOUTHEAST TOWARD THE AREA OVERNIGHT.
CURRENT THINKING IS THAT CONVECTIVE ACTIVITY NEAR THE FRONT WILL
DIMINISH THIS EVENING WITH THE LOSS OF DAYTIME HEATING AND
FORCING. LATEST MODEL RUNS NOW SUGGEST THAT SUBTLE LOW LEVEL JET
AND ASSOCIATED UPR LVL DISTURBANCE WILL LIKELY STAY TO OUR SOUTH
AND SOUTHWEST OVERNIGHT. AS A RESULT...WITH VERY WEAK
FORCING...CAN NOT SEE GOING MUCH HIGHER THAN 30 POPS FOR ALL
LOCATIONS. WILL UPDATE THE ZONES TO REFLECT THIS. WILL ALSO REMOVE
HEAVY RAIN THREAT GIVEN SPARSE COVERAGE. AMPLE LOW LEVEL MOISTURE
AND DIMINISHING WINDS WILL MAKE FOG AND/OR STRATUS A CONCERN AFTER
MIDNIGHT...ESPECIALLY IF HOLES CAN DEVELOP IN THE MID AND UPPER
LEVEL CLOUDS. WILL CONTINUE TO MENTION AREAS OF FOG IN THE ZONES
AFTER MIDNIGHT AS WELL AS IN THE HWO. LOWS WILL RANGE FROM THE
UPPER 60S NW TO THE LOWER 70S ELSEWHERE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
THE LOWER GREAT LAKES AND OHIO VALLEY REGION WILL BE BETWEEN A
LARGE ANOMALOUS UPR LVL LOW OVER ONTARIO AND A MID LVL SUBTROPICAL
RIDGE OVER THE SRN STATES THROUGH THE SHORT TERM PERIOD. THIS
SETUP WILL ONLY ALLOW AFOREMENTIONED FRONTAL SYSTEM TO MOVE EVER
SO SLOWLY TO SOUTHEAST...EVENTUALLY STALLING NEAR THE OHIO RIVER
BY FRIDAY MORNING AS MID LEVEL FLOW BECOMES ZONAL. THE FRONT WILL
PROVIDE THE FOCUS FOR SHOWERS AND STORMS THROUGH THE PERIOD...BUT
THE TIMING AND AREAL COVERAGE WILL BE PROBLEMATIC AS MODELS ARE
ESSENTIALLY OFFERING DIFFERENT SOLUTIONS. HAVE GONE WITH A
NAM/ECMWF BLEND WHICH IS FORECASTING A SLOWER FRONTAL MOVEMENT. AS
SUCH...THERE IS A HINT OF A FRONTAL WAVE RIPPLING ALONG THE FRONT
ON THURSDAY THROUGH THE HEART OF THE FORECAST AREA. THIS WAVE AND
ANY UPR LVL SUPPORT FROM AN ASSOCIATED DISTURBANCE OR MCV SHOULD
PROVIDE THE BEST CHANCE FOR SHOWERS AND STORMS ALONG AND SOUTHEAST
OF THE LOW. HAVE HIGHEST POPS MAINLY FOR POINTS ALONG AND
SOUTHEAST OF INTERSTATE 71 WITH THE DIURNAL CYCLE PLAYING A ROLE
IN TERMS OF BEST COVERAGE.
LOOKS LIKE WAVE MOVES OFF TO THE NORTHEAST THURSDAY NIGHT...WHICH
SHOULD RESULT IN A DOWN TICK IN SHOWER/THUNDERSTORMS COVERAGE IN
ITS WAKE.
THE AIRMASS WILL BE QUITE MOIST ALONG AND AHEAD OF THE FRONT WITH
PWATS OF 2 INCHES PLUS EXPECTED. IN ADDITION...WARM CLOUD DEPTHS
WILL BE CLOSE TO 4 KM WHICH WOULD FAVOR COLLISION/COALESCENCE
PROCESSES AND THE POTENTIAL FOR HEAVY RAIN. GIVEN THE UNCERTAINTY
IN PLACEMENT OF HEAVIEST RAIN WITH UPCOMING ROUNDS OF SHOWERS AND
STORMS...WILL CONTINUE TO HIGHLIGHT THE HEAVY RAIN THREAT/LOCAL
FLOODING ISSUES IN THE HWO WITH AN EMPHASIS PLACED ACRS THE SRN
CWFA CLOSER TO THE FRONTAL BOUNDARY.
HIGHS ON THURSDAY SHOULD BE HELD DOWN BY CLOUDS AND PCPN...WITH
LOWER TO MID 80S EXPECTED. LOWS THURSDAY NIGHT WILL RANGE FROM THE
MID 60S NW TO THE LOWER 70S SOUTH.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
MAIN FOCUS FOR THE FIRST PART OF THE EXTENDED PERIOD WILL BE A
SURFACE FRONTAL BOUNDARY THAT WILL ORIENT ITSELF ALONG THE OHIO
RIVER FRIDAY MORNING. WITH ZONAL FLOW ALOFT...THIS BOUNDARY WILL
VERY SLOWLY SAG SOUTHWARD THROUGH THE WEEKEND. ONE WAVE OF LOW
PRESSURE RIDING ALONG THE FRONT WILL BE EXITING TO THE NORTHEAST AT
THE START OF THE PERIOD...ONLY TO BE FOLLOWED BY ANOTHER RIPPLE
FRIDAY NIGHT INTO SATURDAY. SOUTHERN PORTIONS OF THE FA WILL SEE THE
GREATEST CHANCE FOR RAIN THROUGH THE WEEKEND AND LATEST
DETERMINISTIC RUNS CONTINUE TO INDICATE PW VALUES IN THE 150 TO 175
PERCENT OF NORMAL RANGE THERE THROUGH FRIDAY NIGHT. WITH SEVERAL
ROUNDS OF SHOWERS AND STORMS IN THE FORECAST...WILL CONTINUE TO
MONITOR THE POSSIBILITY OF SOME LOCALIZED FLOODING ACROSS THE SOUTH.
THE 12Z GFS AND ECMWF HAVE BOTH NUDGED QPF A TAD FURTHER SOUTH
FOR SATURDAY AND SUNDAY THAN THEY HAD IN EARLIER RUNS...SO OPTED TO
LOWER OR TAKE OUT POPS ACROSS THE NORTHERN HALF OF THE FA THROUGH
THE WEEKEND. KEPT CHANCE POPS IN ACROSS THE SOUTH WHILE THE FRONT
LINGERS NEAR THE OHIO RIVER. BY MONDAY A MID LEVEL TROUGH OVER
EASTERN CANADA WILL BEGIN TO AMPLIFY...RESULTING IN NW FLOW OVER THE
OHIO VALLEY BY THE MIDDLE OF NEXT WEEK. MEANWHILE SURFACE HIGH
PRESSURE WILL BUILD OVER THE GREAT LAKES WHICH SHOULD PROVIDE A
PERIOD OF DRIER WEATHER FOR TUESDAY AND WEDNESDAY. TEMPERATURES
THROUGH THE PERIOD WILL REMAIN A FEW DEGREES BELOW NORMAL WITH HIGHS
IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SLOW MOVING COLD FRONT MOVING INTO NW OHIO WILL SLIP INTO CENTRAL
OHIO THIS AFTERNOON AND STALL OUT NEAR THE OHIO RIVER TONIGHT.
SCATTERED STORMS WERE DEVELOPING AHD OF THIS FRONT ACRS PORTIONS
OF CENTRAL AND SRN OHIO WHERE BLYR CAPE WERE APPROACHING 1000
J/KG. HAVE TEMPO MENTION OF STORMS WITH MVFR CONDITIONS AT
KDAY/KCMH AND KLCK WHERE COVERAGE LOOKS BEST.
FOG AND STRATUS IS EXPECTED AGAIN EARLY THIS MORNING IN MOIST
ENVIRONMENT. IFR CIGS/VSBYS ARE POSSIBLE IN ANY LOCATION BUT MORE
LIKELY AT KCVG/KLUK AND KILN.
GENERALLY EXPECT CONDITIONS LIFTING TO MVFR AFTER SUNRISE.
THUNDERSTORM CHANCES CONTINUE TO INCREASE WITH THE FRONT SLIPPING
A LTL FURTHER SOUTH AND BLYR LAYER CAPES OF 1200-1800 J/KG DURG
THE AFTN. HAVE MENTION OF VCTS AND THEN PLACED PREVAILING PRECIP
IN THE TIME FRAME WHEN THREAT APPEARS BEST. HOWEVER...UNCERTAINTY
EXISTS REGARDING TIMING AND PLACEMENT DUE TO MODEL SOLN DIFFERENCES
REGARDING FRONTAL MOVEMENT. GIVEN WESTERLY UPPER LEVEL FLOW WHICH
BACKS SLIGHTLY TONIGHT...PREFER SLOWER MOVEMENT MORE LIKE THE
GFS/ECMWF SOLNS WITH THE NAM APPEARING TO BE TOO FAST.
OUTLOOK...THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES
THROUGH FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...FRANKS/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...KURZ
AVIATION...AR
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
315 AM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH SATURDAY. A
WEAK COLD FRONT ARRIVE FROM THE NORTH SUNDAY. THIS FRONT WILL SLOWLY
CROSS THE AREA THROUGH TUESDAY...BEFORE MOVING SOUTH OF THE AREA ON
WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE LATEST GSP-WSR88D WIND PROFILER DATA SHOW NORTHERLY FLOW BETWEEN
9-13 KFT. WHILE AT THE TCLT TDWR THE FLOW AT THIS LEVEL IS OUT OF
THE WSW. THE TROUGH IS ALSO EVIDENT IN THE REFLECTIVITIES AS PATCHY
LIGHT SHOWERS ARE MOVING OUT OF THE NORTH OVER THE CENTRAL PART OF
THE UPSTATE...BUT THEY ARE MOVING FROM THE SOUTH OVER TOWARD UNION
AND GAFFNEY. WHILE THIS IS A WEAK FEATURE IT MAY BE ENOUGH TO
FINALLY KEEP IT DRY THROUGH SUNRISE ON THE BACK SIDE OF THE TROUGH
ACROSS THE BLUE RIDGE. A COUPLE CONVECTION ALLOWING MODELS FIRE UP
HEAVIER SHOWERS AND STORMS EAST OF THE TROUGH AXIS PRIOR TO SUNRISE
HOWEVER. I/M NOT CERTAIN THAT THIS WON/T HAPPEN...BUT I DOUBT IT AT
THIS POINT.
LATER IN THE MORNING THE NAM AND RUC DEVELOP CONVECTION BACK ACROSS
THE BLUE RIDGE AS A STRONGER MID-TROPOSPHERIC TROUGH APPROACHES.
THIS FEATURE IS CURRENTLY EVIDENT ON THE RUC...AND MODESTLY EVIDENT
ON WATER VAPOR IMAGERY...OVER MIDDLE TN AND SW KY. THE SHORT WAVE IS
EXPECTED TO TRIGGER NUMEROUS SHOWERS AND TSTMS OVER MOUNTAINS AND
FOOTHILLS TODAY. EVEN THE PIEDMONT MIGHT GET INTO THE ACT AS THE
LLVL FLOW IS A LITTLE MORE SOUTHWESTERLY TODAY. AS SEVERAL INCHES OF
RAIN HAS FALLEN OVER PARTS OF NE GA...UPSTATE SC AND THE SRN MTNS OF
NC OVER THE PAST 3 DAYS...I/VE ISSUED A FLASH FLOOD WATCH FOR THIS
AREA. I DID NOT TAKE IT ACROSS NRN MTNS...NRN FOOTHILLS OR THE WRN
NC/SC PIEDMONT AS ANTECEDENT CONDITIONS ARE DRIER. I HOPE I DON/T
REGRET THIS...BUT THE NEIGHBORING OFFICES ARE IN AGREEMENT ON THIS
APPROACH AS WELL.
OVERNIGHT THE AREA OF MID-LEVEL TROUGHING STRENGTHENS JUST A LITTLE
WITH SOUTHWESTERLY H5 WINDS INCREASING TO 25 KTS OVER THE WRN ZONES
ALONG WITH A COMMISERATE RESPONSE AND BACKING IN THE LLVL WIND
FIELD. THIS MAY SET THE STAGE FOR CONVECTION TO LAST A WAYS INTO THE
OVERNIGHT HOURS...OR EVEN REDEVELOP AT SOME POINT DURING THE THE
NIGHT. THE FLASH FLOOD WATCH WILL BE RUN THROUGH 6 AM FRIDAY TO
ACCOUNT FOR THIS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AT 230 AM EDT THURSDAY...AN UPPER RIDGE WILL EXTEND ACROSS THE
SOUTHEAST STATES ON FRIDAY...WHILE A CLOSED UPPER LOW CROSSES SOUTH
CENTRAL CANADA AND AN EASTERLY WAVE MOVES INTO THE SOUTHEAST GULF
OF MEXICO. THE RIDGE PERSISTS INTO SATURDAY...WHILE THE UPPER LOW
REACHES EASTERN CANADA...AND THE EASTERLY WAVE REACHES THE WESTERN
GULF.
AN ATLANTIC SURFACE RIDGE WILL MAINTAIN A HOLD ON THE CAROLINAS AND
GA ON FRIDAY...WHILE A RIVER OF GULF MOISTURE WILL EXTEND TO THE
SOUTHERN APPALACHIANS. ISENTROPIC UPGLIDE OVER THE RIDGE WILL BE
RATHER WEAK...AND UPSLOPE FLOW LIMITED BY THE SOUTHWESTERLY NATURE
OF THE WINDS. THE RIVER OF GULF MOISTURE BECOMES REORIENTED ON
SATURDAY AS THE EASTERLY WAVE AFFECTS THE GULF INFLOW...AND LOW
LEVEL WINDS VEER TO THE WEST...FAVORING THE TN BORDER FOR
PRECIPITATION. MEANWHILE...A SLOW MOVING COLD FRONT WILL OUT OF THE
OH RIVER VALLEY...APPROACHING OUR AREA FROM THE NORTH ON SUNDAY
NIGHT.
WITH DEEP MOISTURE REMAINING OVER OUR AREA...POPS WILL BE ABOVE
CLIMATOLOGY...AND WILL CONTINUE OVERNIGHT...DESPITE THE LACK OF WELL
DEFINED FORCING. ALTHOUGH QPF WILL BE LIMITED...ESPECIALLY AS FLOW
VEERS SATURDAY...THE LONG DURATION OF THE EVENT COULD PRODUCE RUNOFF
PROBLEMS IN AREAS THAT HAD GREATER RAINFALL EARLIER ON. A LIMITED
DIURNAL TEMPERATURE RANGE IS EXPECTED TO CONTINUE...WITH CLOUDS
KEEPING MAXIMUMS SLIGHTLY BELOW NORMAL...AND MINIMUMS SLIGHTLY ABOVE
NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AT 230 AM EDT THURSDAY...AN UPPER TROUGH WILL AMPLIFY ALONG THE EAST
COAST FROM SUNDAY THROUGH WEDNESDAY. A COLD FRONT WILL DROP VERY
SLOWLY SOUTH INTO THE NORTHERN PORTION OF THE AREA ON SUNDAY...
CROSSING MUCH OF WESTERN NC ON MONDAY...THE INTERSTATE 85 CORRIDOR
TUESDAY...AND FINALLY MOVING SOUTH OF THE AREA ON WEDNESDAY.
ALTHOUGH THIS BOUNDARY WILL SERVE AS A FOCUSING MECHANISM FOR
PRECIPITATION...SOUTHERLY INFLOW AHEAD OF THE FRONT IS EXPECTED TO
DECREASE BASED ON A REORIENTATION OF THE SURFACE RIDGE TO THE SOUTH.
UPSLOPE WILL BE LIMITED TO THE TN BORDER AREA TO BEGIN WITH AS LOW
LEVEL WINDS WILL BE WESTERLY...AND WILL DIMINISH IN THE LEE OF THE
MOUNTAINS AS THE FRONT SETTLES SOUTH AND WINDS VEER MORE TO THE
NORTHWEST. POPS WILL REMAIN ABOVE CLIMATOLOGY...AND WITH SOME
UNCERTAINTY AS TO THE TIMING OF THE FRONT...POPS WILL BE ALLOWED TO
REMAIN INTO WEDNESDAY. TEMPERATURES WILL DECREASE AS HEIGHTS FALL
ALOFT...BUT THE DIURNAL RANGE WILL REMAIN LIMITED DUE TO CLOUDS AND
MOISTURE.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AT KCLT...A SOLID DECK OF MID LEVEL CLOUDS HAS DEVELOPED UP AROUND
140KFT. THERE ARE A COUPLE OTHER LOWER DECKS AS WELL. SOME LIGHT
RAIN IS FALLING OUT OF SOME OF THESE CLOUDS. EXPECT IFR STRATUS TO
DEVELOP...BUT IT SHOULD TAKE A WHILE WITH ALL THE HIGHER LEVEL
CLOUDS. ALSO...A COUPLE COMPUTER MODELS DEVELOP THUNDERSTORMS AND
HEAVY RAIN STARTING IN A COUPLE HOURS. THERE HAS BEEN PLENTY OF
OVERNIGHT THUNDERSTORM ACTIVITY LATELY SO I/M NOT COMPLETELY
DISREGARDING THIS...BUT I HAVEN/T INCLUDED THAT IN THE TAFS.
STRATUS WILL SLOWLY BURN OFF DURING THE MORNING HOURS. SCT SHRA AND
TSTMS ARE EXPECTED IN THE AFTN...THOUGH CHANCES WILL CONTINUE TO BE
HIGHER A LITTLE CLOSER TO THE MOUNTAINS.
ELSEWHERE...SEVERAL DIFFERENT CLOUD LAYERS COVER THE REGION EARLY
THIS MORNING. THERE IS A DECK UP AROUND 140KFT AND SEVERAL LOWER
ONES AS WELL. HOWEVER...MOST OF THESE CLOUDS ARE IN THE VFR RANGE.
WITH A VERY MOIST ATMOSPHERE AND LIGHT SW WINDS WE SHOULD SEE IFR
STRATUS DEVELOP...THOUGH IT MAY BE PATCHY CONSIDERING THE HIGH CLOUD
COVER. I HAVE ACCOUNTED FOR THIS WITH A LONG PERIOD OF TEMPO
GROUPS. THE EXCEPTION MAY BE KAVL WHERE LIFR CIGS HAVE ALREADY
DEVELOPED. CLOUDS ARE NOT AS THICK OVER HKY WHICH WILL GIVE THEM A
BETTER CHANCE OF A SOLID IFR STRATUS DECK AND SOME FOG. SHRA AND
EVEN A FEW TSMTS MAY DEVELOP OVER THE REGION IN A FEW HOURS. BETTER
CHANCES WILL BE FOUND THIS AFTERNOON...UNLESS THE CONVECTION SIMPLY
KEEPS GOING TROUGH THE MORNING HOURS LIKE IT DID YDAY.
OUTLOOK...MOISTURE AND INSTABILITY CONTINUE THROUGH THE WEEKEND...
LEADING TO CONTINUED CHANCES FOR MAINLY DIURNAL CONVECTION. EARLY
MORNING PATCHY FOG AND LOW CLOUDS MAY OCCUR OVER AREAS OF RECENT
RAINFALL AND IN MTN VALLEYS.
CONFIDENCE TABLE...
07-13Z 13-19Z 19-01Z 01-07Z
KCLT HIGH 81% MED 74% HIGH 91% HIGH 100%
KGSP MED 76% MED 79% HIGH 85% HIGH 83%
KAVL HIGH 86% HIGH 83% HIGH 85% HIGH 80%
KHKY LOW 46% MED 79% MED 77% MED 78%
KGMU MED 71% MED 76% HIGH 87% HIGH 83%
KAND LOW 58% MED 69% HIGH 90% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...JAT
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1145 PM CDT WED AUG 7 2013
.UPDATE...
UPDATED FOR 06Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 740 PM CDT WED AUG 7 2013/
UPDATE...
DIFFICULT TO GET A HANDLE ON EXACTLY WHERE ANY SHOWERS AND
THUNDERSTORMS WILL DEVELOP THIS EVENING WITH MANY OF THE MODELS
BEING POOR IN HANDLING THE CURRENT SITUATION. A WEAK WARM EXTENDS
FROM NORTHEAST AR INTO SOUTHWEST TN AT EARLY EVENING. A FEW
SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG THE TN RIVER IN
WEST TN JUST NORTH OF THIS FRONT. THE HIGH RESOLUTION RAPID
REFRESH MODEL SEEMS TO BE DOING THE BEST JOB...AND THIS MODEL
INDICATE FURTHER DEVELOPMENT THIS EVENING NORTH OF THE FRONT
ACROSS PORTIONS OF NORTHEAST AR...THE MO BOOTHEEL...AND PORTIONS
OF WEST TN. UPDATED TO REMOVE MENTION OF RAIN THIS EVENING SOUTH
OF THIS AREA. ALSO ADJUSTED THE SKY COVER A LITTLE FOR THIS
EVENING...OTHERWISE LITTLE CHANGE MADE TO THE EARLIER FORECAST.
JCL
&&
.PREV DISCUSSION... /ISSUED 312 PM CDT WED AUG 7 2013/
THE OUTFLOW BOUNDARY GENERATED FROM THIS MORNINGS MCS CONTINUES TO
PUSH ACROSS NORTHERN MISSISSIPPI. SCATTERED SHOWERS AND THUNDERSTORMS
HAVE DEVELOPED ALONG AND IN ADVANCE OF THE BOUNDARY AND WILL
CONTINUE TO PUSH ACROSS THE REMAINDER OF NORTH MISSISSIPPI OVER
THE NEXT COUPLE OF HOURS. THESE STORMS COULD BE STRONG WITH GUSTY
WINDS AND HEAVY RAIN. THE BOUNDARY HAS LIMITED HIGH TEMPS ACROSS
THE DELTA THOUGH THE SOUTHERN MOST COUNTIES...FROM TALLAHATCHIE TO
MONROE...HAVE WARMED INTO THE MID 90S WITH HEAT INDEX VALUES
FLIRTING WITH 105 DEGREES. THE REMNANTS OF THE COLD POOL HAVE
RESULTED IN A RELATIVELY NICE DAY ACROSS MUCH OF EASTERN AR...THE
MO BOOTHEEL AND WEST TENNESSEE WHERE TEMPS ARE MOSTLY IN THE 80S
TO AROUND 90. THE AIRMASS STILL QUITE STABLE AND PRECIP FREE.
TONIGHT...LOOKING AT A FAIRLY QUIET EVENING GIVEN THE WORKED OVER
AIRMASS IN PLACE. WENT WITH A 20 POP OVER MOST OF THE AREA AND A
30 POP OVER NE ARKANSAS WHERE THE HRRR IS HINTING AT SOME
DEVELOPMENT BEFORE MIDNIGHT. LOOKING AT ANOTHER POTENTIAL MCS
SCENARIO LATER TONIGHT AS THE LOW LEVEL JET REDEVELOPS OVER
EASTERN OK AND WESTERN AR AND IMPINGES UPON THE WEAK STATIONARY
FRONT ACROSS THE AREA. THIS FRONT HAS BEEN HAVING TROUBLE LIFTING
NORTH OVER THE LAST COUPLE OF DAYS THANKS TO THE RECENT MCS
ACTIVITY AND ASSOCD COLD POOLS. AN AREA OF SHOWERS AND
THUNDERSTORMS SHOULD BLOSSOM OVER SRN MISSOURI AFTER MIDNIGHT AND
THEN HEAD ESE AND SKIRT THE NORTHERN TIER OF THE MIDSOUTH BY
MORNING. POPS WILL DECREASE SHARPLY TOWARD SOUTHERN AREAS OF THE
MIDSOUTH. ANOTHER MILD NIGHT ON TAP WITH LOWS IN THE MID 70S.
THURSDAY...EXPECT THE MCS TO SKIRT THE NORTHERN TIER AND WEAKEN AS
IT SPREADS EAST. BEST CHANCE WILL BE ACROSS NORTHERN AND EASTERN
SECTION WITH LESSER CHANCES TOWARD THE SOUTHWEST. MEX GUIDANCE
CONTINUES TO BE VERY WARM AND WENT CLOSER TO THE COOLER MET
GUIDANCE. EXPECT THAT ANOTHER OUTFLOW BOUNDARY MAY PUSH SOUTH WHICH
WILL HELP KEEP A LID ON TEMPS. AREAS SOUTHWEST OF MEMPHIS ARE
LIKELY TO GET THE WARMEST AND COULD FLIRT WITH HEAT ADVISORY
CRITERIA.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...PATTERN REMAINS SIMILAR
WITH A BROAD UPPER RIDGE ACROSS THE SOUTHERN U.S AND A WEAK
STATIONARY FRONT ACROSS SOUTHERN MISSOURI. EXPECT MCS DEVELOPMENT
ALONG THIS FRONT EACH NIGHT WITH THE BEST CHANCES OF PRECIP ALONG
THE NORTHERN TIER OF THE MIDSOUTH. CONTINUED TO PREFER THE COOLER
MET GUIDANCE THOUGH PARTS OF NORTH MISSISSIPPI AND EAST CENTRAL
ARKANSAS WILL FLIRT WITH HEAT ADVISORY CRITERIA ON FRIDAY.
SATURDAY THROUGH SUNDAY...CONFIDENCE STARTING TO WANE AT THIS
POINT. UPPER RIDGE REMAINS ACROSS THE SOUTHERN U.S. WHILE THE WEAK
BOUNDARY TRIES TO SLIP SOUTH INTO THE MIDSOUTH BUT REALLY DOES
NOT MOVE MUCH. CHANCES FOR SHOWERS AND THUNDERSTORMS EXPECTED ACROSS
THE REGION. MEX STILL TOO WARM.
MONDAY THROUGH WEDNESDAY...MEDIUM RANGE MODELS INDICATE THAT AN
UPPER TROF WILL DEVELOP OVER THE EASTERN U.S. EARLY NEXT WEEK. THE
GFS IS NOT AS DEEP WITH THE TROF WHICH REESTABLISHES NORTHWEST
FLOW ACROSS THE REGION AND KEEPS THE SURFACE BOUNDARY IN THE AREA
RESULTING IN A RENEWED MCS PATTERN. THE ECMWF HAS A DEEPER TROF
AND ACTUALLY PUSHES THE FRONT SOUTH...SHUTTING OFF PRECIP
CHANCES. FOR NOW JUST WENT WITH A COMPROMISE OF 20 POPS AND
SLIGHTLY COOLER THAN NORMAL TEMPS.
SJM
&&
.AVIATION...
06Z TAF CYCLE
GROWING CONFIDENCE THAT THIS TAF PERIOD WILL BECOME A BIT MORE
ACTIVE THEN PREVIOUS 00Z THINKING...WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS DEVELOPING IN THE MEM...JBR...MKL CORRIDOR
BEFORE SUNRISE WITH MVFR VISIBILITIES AT TIMES. BETTER CHANCES
FOR THUNDER WILL BE LATER IN THE DAY AS THE CURRENT DISTURBANCE IN
THE SOUTHERN PLAINS MOVES ACROSS THE OZARKS. FOR NOW...PLACED
TEMPO IN AT JBR...AND VCTS ELSEWHERE...BUT TIMING/COVERAGE COULD
EASILY CHANGE WITH LATER FORECASTS.
WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT...WITH THE EXCEPTION
OF SOUTH WINDS AT MEM. OUTFLOW BOUNDARY FROM MORNING COMPLEX WILL
SHIFT THE WINDS MORE EASTERLY AT 6-8 KTS FOR MEM...MKL AND
JBR...WHILE TUP REMAINS SOUTH. WINDS WILL AGAIN BECOME LIGHT FROM
THE EAST AND SUTHEAST NEAR SUNSET.
JAB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 77 93 78 94 / 30 30 10 30
MKL 73 88 74 91 / 50 60 30 40
JBR 75 90 75 92 / 50 40 30 40
TUP 75 93 75 93 / 20 40 10 40
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1030 AM EDT THU AUG 8 2013
.SYNOPSIS...
SHOWERS AND HUMIDITY WILL INCREASE TODAY AS A WEAK WARM FRONT
MOVES NORTH OF THE REGION. A COLD FRONT WILL SHIFT SLOWLY INTO
NEW ENGLAND THURSDAY AND FRIDAY BRINGING SHOWERS AND
THUNDERSTORMS...SOME WITH HEAVY RAINFALL. THIS FRONT WILL FINALLY
PUSH OFF THE COAST SATURDAY. HIGH PRESSURE BUILDS OVER THE REGION
SUNDAY AND MONDAY. ANOTHER COLD FRONT BRINGS SHOWERS ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
MORNING ACTIVITY LOCALIZED ALONG THE H85 DEWPOINT GRADIENT AND
ATTENDANT LOW- TO MID-LEVEL WARM FRONT PRESSING EAST THRU THE GULF
OF MAINE DRAPING SOUTHWESTWARD TOWARDS NANTUCKET. AS SEEN PER
WSR-88D RETURNS...RAIN DIMINISHING ACROSS THE SOUTHEAST OUTER
WATERS. WILL CONTINUE CHANCE POPS ALONG THE DEWPOINT GRADIENT THRU
THE DAY WITH SLIGHT CHANCE POPS EAST OF THERE WITHIN THE MORE
DRIER AIR.
FOCUSING BACK ON THE INTERIOR...ENTRENCHING INTO THE WARM-MOIST
SECTOR AS THE SURFACE WARM FRONT ACROSS THE NORTHERN HUDSON RIVER
VALLEY DRAPED SOUTH THROUGH WESTERN AND CENTRAL PORTIONS OF NEW
ENGLAND SLOWLY PUSHES EAST AGAINST OFFSHORE HIGH PRESSURE AND
DRIER AIR. MODEST SURFACE-H85 SOUTHWEST MOISTURE TRANSPORT PUSHING
UPPER 60S INTO 70S DEWPOINTS INTO NEW ENGLAND /RETURN OF MUGGY
CONDITION/ RESULTING IN PWATS GETTING UP TO 2 INCHES.
SO WE HAVE THE MOISTURE...NOW ITS A QUESTION OF DESTABILIZATION.
BUT A CAVEAT. 12Z ALBANY SOUNDING AND RAP MESOANALYSIS SHOWS A DRY
POCKET OF AIR ACROSS THE CENTRAL TO LOWER HUDSON RIVER VALLEY.
EARLIER LINE OF STORMS ACROSS UPSTATE NY INTO NORTHERN PA HAS RUN
INTO THIS AIRMASS AND DIMINISHED ENTIRELY. RAP FORECAST GUIDANCE
HAS THIS AIRMASS MOVING EAST INTO NEW ENGLAND DURING THE DAY
RESULTING IN THE POSSIBILITY OF LITTLE TO NO ACTIVITY. ADDITIONAL
GUIDANCE IS FAIRLY QUIET AS WELL WITH THE WRF-ARW THE MOST ROBUST.
CONSIDERING THE 12Z SOUNDING OUT OF BUFFALO WHICH LOOKS MORE
FAVORABLE FOR THUNDERSTORM DEVELOPMENT...FEEL THIS AIRMASS WILL
PUSH EAST INTO THE HUDSON VALLEY DURING THE DAY. FACTORING IN
SUNSHINE AND A DESTABILIZING BOUNDARY LAYER...EXPECT MLCAPE
INSTABILITY UP TO 2K J/KG SHOULD BE UTILIZED. USING A THRESHOLD OF
SURFACE LIFTED INDICES OF -4C...HAVE DEFINED WHERE THERE IS A
BETTER CHANCE OF THUNDERSTORMS WHICH IS MAINLY ACROSS WESTERN AND
CENTRAL PORTIONS OF NEW ENGLAND.
WILL KEEP POPS AT CHANCE. WILL NOT MENTION ANY THREATS TILL
ACTIVITY DEVELOPS DUE TO CONTINUED UNCERTAINTY. MID-LEVEL LAPSE
RATES ARE POOR. BULK SHEAR IS WEAK WHILE UNI-DIRECTIONAL. SO ANY
THREATS LOOK TO BE POSSIBLE WIND DAMAGE WITH HEAVY RAIN AND
NUISANCE FLOODING. HAVE A FEELING TODAY MAY NOT MATERIALIZE INTO
MUCH THAN SCATTERED ACTIVITY WEST THAT REMAINS FAIRLY WEAK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT AND FRIDAY...
SEVERAL MEMBERS OF THE MODEL SUITE...NAMELY THE 00Z GFS AND 12Z
ECMWF ALONG WITH THEIR ENSEMBLES APPEAR TO HAVE A GOOD HANDLE ON
THE EVOLUTION OF THE SLOW MOVING COLD FRONT ACROSS THE REGION. H5
WINDS WITH THE UPPER TROUGH BACK TO SW...WHICH WILL ALLOW DEEP
MOISTURE PLUME TO MOVE ACROSS THE REGION. EXPECT SHOWERS AND
THUNDERSTORMS TO PRODUCE LOCALLY HEAVY RAINFALL DURING THIS
TIMEFRAME. MORE DETAILS IN THE HYDRO SECTION BELOW.
FRIDAY COULD BE INTERESTING WITH SOME OF THE THUNDERSTORMS. MIXED
LAYER CAPE VALUES FORECAST TO 1000-1500 J/KG DURING THE AFTERNOON
AHEAD OF THE FRONT...ALONG WITH A WEAK MID LEVEL DISTURBANCE MOVING
ACROSS THE REGION. ALSO FAIRLY GOOD SHEAR IN PLACE WITH SW WINDS
AROUND 30 KT. THIS MAY PRODUCE SOME LOCALLY GUSTY WINDS IN ANY
STRONGER THUNDERSTORMS. WILL NEED TO MONITOR THIS FOR POSSIBILITY
OF LOCALLY DAMAGING WINDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
BIG PICTURE/PREFERENCES...
SUBTROPICAL RIDGE HOLDS ACROSS THE SOUTHERN USA AND BUILDS OVER
THE ROCKIES INTO WESTERN CANADA. CLOSED UPPER LOW EJECTS THROUGH
EASTERN CANADA FRIDAY-SATURDAY. A SHORTWAVE FROM THE CANADIAN
ARCTIC THEN DROPS SOUTH THROUGH HUDSON BAY...MAINTAINING AND
POSSIBLY DEEPENING THE UPPER TROUGH OVER EASTERN CANADA/NORTHEAST
USA DURING THE FIRST HALF OF NEXT WEEK. THERMAL FIELDS SHOW
COOLING ALOFT OVER THE WEEKEND AND EARLY NEXT WEEK. THE ECMWF
SHOWS A COUPLE OF DEGREES MORE COOLING THAN THE GFS.
OUR MAIN PREFERENCE WAS HPC/WPC GRIDS WHERE AVAILABLE...A BLEND OF
GFS/ECMWF GRIDS OTHERWISE.
THE DAILIES...
FRIDAY NIGHT-SATURDAY...
A COLD FRONT MOVES THROUGH THE REGION OVERNIGHT. THIS IS DRIVEN
BY THE UPPER LOW PASSING NORTH OF NEW ENGLAND. THERE IS SOME
VARIATION IN THE PLACEMENT OF THE COLD FRONT FRIDAY EVENING...BUT
THE 00Z ECMWF AND GENERAL CONSENSUS CENTER ON THE HUDSON VALLEY.
SUFFICIENT LIFT/INSTABILITY AND PRECIPITABLE WATER VALUES 2 INCHES
OR HIGHER ALL POINT TO SHOWERS/TSTMS LEADING THE FRONT. COVERAGE
MAY NOT BE 100 PERCENT AS IS NORMAL FOR SHOWERS...BUT STRONG
CONFIDENCE IN OCCURRENCE. DEEP MOISTURE/HIGH PW VALUES SUGGEST
HEAVY DOWNPOURS WITH POTENTIAL FOR URBAN/POOR DRAINAGE FLOODING. A
FLASH FLOOD WATCH MAY BE NEEDED IN THE NEAR FUTURE TO COVER THIS
PRE-FRONTAL WEATHER. THE COLD FRONT SWEEPS ACROSS SOUTHERN NEW
ENGLAND DURING THE NIGHT WITH SHOWERS TAPERING OFF WITH FRONTAL
PASSAGE AND THE WIND SHIFT TO NORTHWEST. HIGH DEWPOINTS IN THE
EVENING...BUT LOWERING AFTER FROPA OVERNIGHT.
COULD BE SOME LINGERING CLOUDS/SHOWERS ALONG THE EAST AND SOUTH
COASTS SATURDAY MORNING BUT THE OVERALL TREND WILL BE FOR CLEARING
AND DIMINISHING HUMIDITY. MIXING SHOULD REACH TO AT LEAST 850 MB
AND POSSIBLY HIGHER. TEMPS AT THE TOP OF THE MIXED LAYER SHOULD
REACH 12-15C...WHICH WOULD ALLOW MAX TEMPS IN THE LOW TO MID 80S. A
MILD START COULD ADD A COUPLE OF DEGREES TO THE HIGH SIDE OF THIS
RANGE. WINDS AT THE TOP OF THIS MIXED LAYER WILL REACH AROUND 20
KNOTS...SO WE ARE FORECASTING A POTENTIAL FOR AFTERNOON GUSTS 20-25
MPH.
SUNDAY-MONDAY...
HIGH PRESSURE BUILDS OVER THE EAST AND SHOULD PROVIDE DRY
SEASONABLE WEATHER BOTH DAYS. SHORTWAVE MOVING ALONG THE CANADIAN
BORDER MAY BRING SOME COOLING ALOFT SUNDAY AND DESTABILIZE THE
AIRMASS FOR SOME DIURNAL CUMULUS. DEWPOINTS IN THE 50S AND LIGHT
WINDS WILL ALLOW EARLY MORNING LOWS IN THE 50S AND LOWER 60S EACH
DAY. TEMPS AT THE TOP OF THE MIXED LAYER WILL SUPPORT MAX TEMPS
AROUND 80 SUNDAY AND 80-85 MONDAY. IF MIXING GOES A LITTLE DEEPER
THAN FORECAST THEN WE MAY GET A COUPLE OF DEGREES WARMER.
TUESDAY...
SHORTWAVE DROPPING SOUTH TO THE GREAT LAKES MONDAY WILL SWING
EAST AND DRIVE PAST NORTHERN NEW ENGLAND TUESDAY. THIS WILL BRING
A COLD FRONT THROUGH THE REGION WHICH MAY GENERATE A FEW
SHOWERS/TSTMS. PW VALUES CLIMB ABOVE 1.5 INCHES WITH THE 2 INCH
CONTOUR LURKING JUST TO OUR SOUTH. SO HEAVY DOWNPOURS MAY AGAIN BE
A CONCERN.
WEDNESDAY...
THE NEXT HIGH PRESSURE AREA MOVES IN WITH DRY SEASONABLE AIR.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW THROUGH FRIDAY...HIGH CONFIDENCE IN TRENDS...LOW CONFIDENCE
IN TIMING.
TODAY...EXPECT MVFR-IFR CIGS ACROSS MOST AREAS WHICH SHOULD
IMPROVE TO VFR BY AFTERNOON. VSBYS MAINLY VFR...THOUGH WILL SEE
LOCAL MVFR-IFR VSBYS IN SHOWERS AND ISOLD TSTMS OFF AND ON
THROUGH THE DAY.
TONIGHT AND FRIDAY...EXPECT CIGS/VSBYS TO LOWER TO MVFR-IFR IN
LOW CLOUDS...PATCHY FOG AND SHOWERS/TSTMS. WILL SEE LOCALLY HEAVY
RAINFALL WHICH WILL ALSO LOWER VSBYS. MAY SEE SLOWLY IMPROVING
CONDITIONS LATE FRIDAY ACROSS SW NH/W MA...DEPENDING UPON THE
TIMING OF THE COLD FRONT.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS...LOW CONFIDENCE IN
TIMING.
KBDL TERMINAL...HIGH CONFIDENCE IN TRENDS...LOW CONFIDENCE IN
TIMING.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT... LOW CIGS AND POOR VSBYS IN SHOWERS/TSTMS AND AREAS
OF FOG. LOCALLY HEAVY DOWNPOURS ARE EXPECTED WITH POTENTIAL FOR POOR
DRAINAGE FLOODING. THE COLD FRONT SHOULD CROSS THE CT VALLEY AROUND
OR JUST AFTER SUNSET...AND REACH THE COASTAL AREAS AROUND MIDNIGHT
OR A LITTLE LATER. EXPECT SHOWERS TO TAPER OFF AFTER THE FRONT MOVES
THROUGH. LOCALLY LOW CIGS/VSBY POSSIBLE OVERNIGHT IN FOG.
SATURDAY-SUNDAY-MONDAY... VFR THROUGH THE PERIOD. NORTHWEST WINDS
SATURDAY MAY GUST TO 25 KNOTS DURING THE AFTERNOON AS DAYTIME
HEATING DRAWS THE STRONGER WINDS LOWER FROM HIGH ALTITUDES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
TODAY THROUGH FRIDAY...HIGH CONFIDENCE.
TODAY AND TONIGHT...EXPECT S WINDS TO PICK UP DURING THE DAY WITH
AN INCREASING S SWELL. WINDS AND SEAS REMAIN BELOW SMALL CRAFT
CRITERIA. SHOWERS/SCT TSTMS EXPECTED WITH REDUCED VSBYS. MAY SEE
HEAVY DOWNPOURS IN SOME SHOWERS AND STORMS TONIGHT. PATCHY FOG
DEVELOPS TONIGHT WITH VSBYS 1-3NM.
FRIDAY...SW WINDS PICK UP DURING THE LATE MORNING AND AFTERNOON...
GUSTING TO 25 KT ON THE OPEN WATERS. SEAS ALSO INCREASE...UP TO 5-6
FT...HIGHEST ON THE SOUTHERN OUTER WATERS. DECIDED TO HOLD OFF ON
PUTTING SMALL CRAFT UP FOR NOW. WILL SEE SHOWERS/TSTMS WHICH MAY
PRODUCE HEAVY DOWNPOURS AND BRIEF GUSTY WINDS. PATCHY FOG AGAIN
REDUCING VSBYS.
OUTLOOK...FRIDAY NIGHT INTO MONDAY...
MODERATE CONFIDENCE.
FRIDAY NIGHT...
SHOWERS/TSTMS MOVE THROUGH DURING THE FIRST PART OF THE NIGHT. A
COLD FRONT WILL MOVE ACROSS THE WATERS LATER IN THE NIGHT WITH
SHOWERS ENDING AND WINDS SHIFTING TO NORTHWEST. SEAS WILL REMAIN
AROUND 5-6 FEET ON THE EXPOSED WATERS UNTIL THE WIND SHIFT AND
THEN DIMINISH. SMALL CRAFT ADVISORY WILL BE LIKELY FOR THESE
AREAS.
SATURDAY THROUGH MONDAY...
WINDS AND SEAS BELOW SMALL CRAFT THRESHOLDS DURING THIS PERIOD.
&&
.HYDROLOGY...
INCREASING LOW LEVEL MOISTURE FEED WILL MOVE INTO THE REGION LATE
TONIGHT AND FRIDAY ALONG A SLOW MOVING COLD FRONT. THE FRONT MAY
STALL FOR A TIME DURING FRIDAY...ALLOWING FOR TRAINING OF PRECIP
ACROSS THE REGION. EXPECT PWATS TO INCREASE TO 2 TO 2.25 INCHES
LATE TONIGHT AND FRIDAY. THIS...ALONG WITH THE INCREASING MOISTURE
CONVERGENCE AND SLOW MOVEMENT OF THE FRONT WILL BRING LOCALLY
HEAVY RAINFALL WITH THE SHOWERS/TSTMS AHEAD OF THE FRONT. QPF
AMOUNTS FORECAST TO BE A GENERAL 1-2 INCHES...BUT COULD SEE
LOCALLY HIGHER AMOUNTS IN HEAVIER PRECIP. HOWEVER...THE LOCATION
AND TIMING OF HEAVIEST RAINS REMAINS IN QUESTION.
MAIN THREAT WILL BE MINOR URBAN AND POOR DRAINAGE FLOODING...BUT
FLASH FLOODING IS POSSIBLE WITH ANY TRAINING CONVECTION. FLASHY
SMALL STREAM FLOODING COULD BECOME A CONCERN IF SEVERAL ROUNDS OF
CONVECTION OCCUR OVER THE SAME BASINS. THIS ASPECT WILL NEED TO
BE MONITORED CLOSELY...AND A FLASH FLOOD WATCH MAY NEED TO BE
ISSUED.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...SIPPRELL
SHORT TERM...EVT
LONG TERM...WTB
AVIATION...WTB/EVT
MARINE...WTB/EVT
HYDROLOGY...WFO BOX STAFF
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1133 AM EDT THU AUG 8 2013
.SYNOPSIS...
LOW PRESSURE MOVING ACROSS SOUTHEASTERN CANADA WILL ALLOW A COLD
FRONT TO APPROACH THE REGION ON FRIDAY AND CROSS THE AREA BY LATE
FRIDAY OR EARLY SATURDAY. THIS FRONT WILL EVENTUALLY STALL TO OUR
SOUTH FOR SUNDAY. EARLY NEXT WEEK, A FEW WAVES OF LOW PRESSURE ARE
FORECAST TO MOVE ALONG THE STALLED BOUNDARY. HIGH PRESSURE WILL
THEN BUILD IN TOWARD MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT A CONFIDENT ESTF UPDATE. WE HAVE DECIDED TO COMPROMISE BETWEEN
PREVIOUS FCST AND CURRENT SUGGESTIONS BY THE HRRR AND COSPA. WE
ARE SEEING A SHORT WAVE EMERGE FROM WV AND COUPLED WITH CONVECTIVE
TEMPERATURES BEING REACHED BELIEVE THIS SHOULD START TRIGGERING
AND ENHANCING CONVECTION AS WE MOVE FORWARD. THE PREVIOUS MCS HAS
LEFT A RELATIVELY STABLE POOL NW OF OUR CWA FOR NOW. SO THE
ADJUSTMENTS GOING FORWARD WERE TO LOWER POPS INITIALLY NORTHWEST
AND GIVE THAT SHORT WAVE A BIT MORE CREDIT AND INCREASE POPS IN
THE CENTRAL THIRD OF OUR CWA FOR THIS AFTERNOON. WE DID SEE A
NOTICEABLE DROP OFF IN 925MB OR 850MB MOISTURE OFF THE WALLOPS
SOUNDING THIS MORNING, SO CHANCES WERE KEPT IN THE SERN PART OF
OUR CWA. WE ARE WARMING AT 700MB AND 500MB, SO WITH BULK SHEAR
VALUES BEST NORTH AS WELL AS FORECAST TT(S), WE KEPT THE SOMEWHAT
ENHANCED WORDING TIED TO LIKELY POPS. THE FCST DCAPES ARE NOT
IMPRESSIVE AND NEITHER ARE THETA E DROP WITH HEIGHT, SO ANY STRONG
TO SEVERE ARE GOING TO HAVE TO BE TIED TO SOME RELATIVELY STRONGER
UPDRAFTS OR IF AN EFFECTIVE COOL POOL CAN FORM. THE LATTER DOES
NOT LOOK PROMISING. WE HAVE NOT HAD MANY DRY STRETCHES THIS
SUMMER, BUT THE RELATIVE LACK OF FLOODING RAINS LAST SEVERAL DAYS
HAS PERMITTED FFG AND FFH GUIDANCE TO GET CLOSER TO NORMAL SUMMER
VALUES. SO WHILE A FFW MIGHT STILL OCCUR, THIS WOULD SEEM TO BE
MORE OF AN ISOLATED OCCURRENCE.
12Z SOUNDINGS GIVE 90F AS A POSSIBLE HIGH SOUTHERN PART OF OUR
CWA (CONVECTIVE TEMP LOW 80S), SO BUMPED MAX TEMPS UPWARD IN
DELMARVA, KEPT THE REST RELATIVELY THE SAME.
UPPER HEIGHTS WILL BE RISING THRU THE DAY AND THERE ARE ONLY WEAK
S/W MOVING THRU THE FLOW. BREAKS WILL OCCUR TODAY ALLOWING FOR
POCKETS OF HEATING/INSTABILITY TO DEVELOP. WE WILL GO ALONG WITH THE
DETERMINISTIC MODELS AND MOS AND MOSTLY KEEP THE HIGHER CHC FOR POPS
NORTH MOSTLY THIS AFTERNOON WITH SLGT CHC OR LOW CHC POPS
SOUTH/EAST. THERE WILL BE SOME CAPE VALUES AROUND 750-1250 J/KG
ACROSS THE AREA...BUT THE HIGHEST VALUES WILL OCCUR WITH ANY
BREAKS IN THE CLOUDS TODAY. SPC HAS OUR AREA IN `SEE TEXT` AND
MENTIONS ONLY SMALL POSSIBILITY OF SOME STRONGER WIND GUSTS WITH
ANY CONVECTION THAT DEVELOPS. QPF BASIN AVERAGES...1/2 INCH NORTH
RANGING DOWN TO LIGHT AMTS SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
WE WILL CONTINUE IN THE WARM SECTOR TONIGHT WITH THE UPPER FLOW
BECOMING A BIT MORE SWRLY ALOFT. A COLD FRONT WILL BE SLOWING ITS
APPROACH INTO WRN NY AND WRN PA. SHOWERS AND SCT THUNDERSTORMS WILL
CONTINUE FROM THE LATE AFTERNOON INTO THE EARLY OVERNIGHT PERIODS.
THE AREAS NORTH/WEST WILL HAVE THE BETTER CHCS FOR THE RAINS. WE
WILL CARRY THE LIKELY POPS INTO THE OVERNIGHT NORTH/WEST AND HOLD
THE HIGHER CHC POPS SOUTH/EAST. QPF...1/2 INCH NORTH 1/10 INCH
SOUTH.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AN AREA OF LOW PRESSURE IN SERN CANAD WILL WORK ITS WAY EWD. AS IT
DOES A CDFNT WILL CROSS THE AREA FROM W TO E ON FRI INTO FRI
NIGHT. THE LATEST MDL GUID CURRENTLY INDICATES THAT THE FRI
DAYTIME PD COULD BE FAIRLY WET, FOR AT LEAST A PORTION OF THE
AREA, AND THERE COULD BE LOCALIZED CONVECTION WHICH COULD MAKE FOR
PDS OF HEAVY RAIN. IT IS PSBL, IF THE MDLS CONTINUE TO AGREE ON A
LOCATION AS THEY ARE NOW (N AND W) THAT A FFA MAY BE NEEDED AS
RNFL AMTS APPEAR TO BE AOA 1 INCH. THE FRONT SHUD CLEAR THE AREA
DURG THE OVERNIGHT HOURS ON FRI AND CLEARING WILL OCCUR FROM N TO
S. PRECIP MAY LINGER ACRS THE DELMARVA INTO ERLY SAT. THE ECMWF
DOES CLEAR THINGS OUT FASTER THAN THE GFS. BOTH MDLS KEEP THE
FRONT CLOSE BY, SO IT WON`T TAKE MUCH IN THE WAY OF A PERTURBATION
FOR IT TO BRING ANOTHER SHOT OF PRECIP, BUT FOR BOTH MDLS DRY
THINGS OUT BY LATER SAT AT THE LATEST, AS HIGH PRESSURE BUILDS IN.
SUN THEN LOOKS DRY. MUCH LESS CONFIDENCE INTO MON AS THE GFS WANTS
TO BRING A WAVE ACRS THE STALLED FRONT, WHICH WOULD BRING PRECIP,
MAINLY ACRS THE S. THE ECMWF IS DRY DURG THIS TIME. THE CMC ALSO
HAS A WAVE ON MON, BUT ITS OVERALL SYNOPTIC PATN IS A BUT SUSPECT
OVERALL. BY TUE, THE MDLS BRING ANOTHER LOW TO THE N AND ANOTHER
CDFNT ACRS THE REGION, AND ANOTHER CHC OF RAIN.
THIS IS A LOW CONFIDENCE FCST FOR THE EARLY PORTION OF NEXT WEEK
AS IT WILL BE DEPENDENT ON THE POSN OF THE FRONT AND IF ANY WAVES
DEVELOP ALG IT AND WHERE THEY MOVE. BASED ON THE ECMWF`S GENLY
SUPERIOR PERFORMANCE, WANT TO GIVE IT A BIT OF A NOD, BUT CAN`T
RULE OUT A MORE PESSIMIST SOLN EITHER. FOR NOW, WILL BRING IN LOW
POPS MON, LOW CHC POPS ON TUE TO SEE HOW THINGS PLAY OUT AND THEN
A DRY FCST ON WED AS HIGH PRESSURE BUILDS IN.
TEMPS WILL GENLY BE AT OR SLIGHTLY ABV NRML THRU THE PD.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...IMPROVING CIGS WITH BREAKS IN THE CLOUDS AND SLOW MIXING
OUT OF ANY LIGHT FOG THIS MORNING...THEN SCT SHOWERS/TSTMS OCCUR
LATER TODAY. LOWER CONDITIONS WITH THE CONVECTION.
TONIGHT...SHOWERS/TSTMS GRADUALLY ENDING. LOWER CIGS/VSBYS AGAIN
INDICTED IN THE GUIDANCE MVFR?...IFR? LOW CONFID OVERALL.
OUTLOOK...
FRIDAY THROUGH EARLY MORNING SATURDAY...MAINLY MVFR OR IFR
CONDITIONS EXPECTED IN SHOWERS AND PSBL TSTMS. SOME HVY RAIN PSBL.
MDT CONFIDENCE.
REMAINDER OF SATURDAY THROUGH MONDAY...MOSTLY VFR CONDITIONS.
ISOLATED SHWRS/TSTMS REMAIN POSSIBLE, ESPECIALLY MON. SUN SHOULD
BE DRY. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
A MODERATE SOUTH WIND CONTINUES ACROSS THE OCEAN WATERS AND MORE OF
A SWLY WIND ACROSS DEL BAY. OVERALL...THE WIND SPEEDS AND SEAS WILL
REMAIN BELOW SCA CRITERIA TODAY AND TONIGHT. A FEW WIND GUSTS TO 25
KTS MAY OCCUR EARLY THIS MORNING AND LATER TONIGHT...BUT THEY WILL
NOT PERSIST. THE MAIN MARINE HAZARD TODAY AND TONIGHT WOULD BE ANY
GUSTY WINDS ASSD WITH TSTMS WHICH WILL BE AROUND EARLY THIS
MORNING...THIS AFTERNOON AND TONIGHT. SEAS...ON THE OCEAN 3-4 FT AND
DEL BAY 1-2 FT (NORTH) AND 2-3FT (SOUTH).
OUTLOOK...
OVERALL, SUB-SCA CONDITIONS ARE EXPECTED FOR OUR AREA WATERS THROUGH
THE BULK OF THE OUTLOOK PERIOD. GUIDANCE IS SHOWING AN INCREASE IN
THE SOUTHERLY TO SOUTHWESTERLY FLOW DURING FRIDAY AHEAD OF AN
APPROACHING CDFNT. THE WIND CUD GUST TO AROUND 20 KTS OR SO AS
WELL DURG THIS TIME. IN ADDITION, WAVEWATCH GUIDANCE ALSO INDICATES
SEAS RISING TO AROUND 5 OR PSBLY 6 FEET FOR OUR COASTAL WATERS
DURING THIS TIMEFRAME. HOWEVER, THIS GUIDANCE TENDS TO RUN A
LITTLE HIGH IN SOUTHERLY FLOW, AND CONFIDENCE IS BELOW AVERAGE. SO
WILL CONTINUE TO MONITOR FOR ANY PSBL FLAGS. SEAS SHOULD THEN
LOWER BEHIND THE CFP INTO THE WEEKEND, AS WINDS SHIFT TO THE NW.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI/O`HARA
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
908 AM EDT THU AUG 8 2013
.SYNOPSIS...
LOW PRESSURE MOVING ACROSS SOUTHEASTERN CANADA WILL ALLOW A COLD
FRONT TO APPROACH THE REGION ON FRIDAY AND CROSS THE AREA BY LATE
FRIDAY OR EARLY SATURDAY. THIS FRONT WILL EVENTUALLY STALL TO OUR
SOUTH FOR SUNDAY. EARLY NEXT WEEK, A FEW WAVES OF LOW PRESSURE ARE
FORECAST TO MOVE ALONG THE STALLED BOUNDARY. HIGH PRESSURE WILL
THEN BUILD IN TOWARD MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUITE THE FORECASTING CONUNDRUM FOR TODAY ACROSS OUR CWA. AS BEST
KINEMATIC AND THERMODYNAMIC SUPPORT FOR CONVECTION IS AT ODDS WITH
ONGOING CLOUD COVER AND LOWER EXPECTED TEMPERATURES. LIKE
YESTERDAY MOST OF THE MESOSCALE MODELS ARE NOT VERIFYING WELL AT
ALL IN OUR CWA THIS MORNING AND THIS INCLUDES THE RAP. CLOSEST TO
REALITY IN OUR CWA HAS BEEN THE NSSL WRF. BECAUSE OF THEIR HOURLY
INITIALIZATION THE HRRR AND COSPA HAVE BEEN DOING OK 1-3HRS DOWN
THE ROAD; THE SAME CAN NOT BE SAID FOR THE RAP. THE LATTER PAIR
ARE DISSIPATING THE MCS BEFORE MUCH OF IT CAN GET INTO OUR NRN CWA
THIS MORNING AND THEN ARE ESTABLISHING A DIFFERENTIAL HEATING
BOUNDARY INDUCED CONVECTION CLOSE TO THE PHL METRO AREA LATER THIS
MORNING. GOING AGAINST THIS IS RELATIVELY DRIER AIR COMING IN
FROM THE ATLANTIC ACROSS THE SERN PART OF OUR CWA. WANT TO SEE HOW
CLEARING EVOLVES BEFORE MAKING ANY BIG CHANGES AS THIS ESTF UPDATE
WILL KEEP THE HIGHEST POPS NW. THERE IS CLEARING BEHIND THE
DEPARTING MCS WESTERN NY AND FORECAST CONVECTIVE TEMPS ARE LOWER
NORTH THAN SOUTH. 12Z SOUNDINGS GIVE 90F AS A POSSIBLE HIGH
SOUTHERN PART OF OUR CWA (CONVECTIVE TEMP LOW 80S), SO BUMPED MAX
TEMPS UPWARD IN DELMARVA, KEPT THE REST RELATIVELY THE SAME.
AN ILL DEFINED WARM FRONT ACROSS THE AREA EARLY THIS MORNING WILL
MOVE OFF TO THE NORTH/EAST LATER TODAY. WE WILL SPEND THE REST OF
TODAY (AND TONIGHT) IN THE WARM SECTOR. ABUNDANT MOISTURE WILL
REMAIN IN PLACE ACROSS THE REGION.
ANOTHER BATCH OF SHOWERS/TSTMS ACROSS WRN NY APPEARS TO BE
WEAKENING SLOW ALSO. IT MAY BRING EXTRA CLOUDINESS LATER THIS
MORNING ACROSS THE NORTH.
UPPER HEIGHTS WILL BE RISING THRU THE DAY AND THERE ARE ONLY WEAK
S/W MOVING THRU THE FLOW. BREAKS WILL OCCUR TODAY ALLOWING FOR
POCKETS OF HEATING/INSTABILITY TO DEVELOP. WE WILL GO ALONG WITH THE
DETERMINISTIC MODELS AND MOS AND MOSTLY KEEP THE HIGHER CHC FOR POPS
NORTH/WEST MOSTLY THIS AFTERNOON WITH SLGT CHC OR LOW CHC POPS
SOUTH/EAST. THERE WILL BE SOME CAPE VALUES AROUND 750-1250 J/KG
ACROSS THE AREA...BUT THE HIGHEST VALUES WILL OCCUR WITH ANY BREAKS
IN THE CLOUDS TODAY. SPC HAS OUR AREA IN `SEE TEXT` AND MENTIONS
ONLY SMALL POSSIBILITY OF SOME STRONGER WIND GUSTS WITH ANY
CONVECTION THAT DEVELOPS. QPF...1/2 INCH NORTH RANGING DOWN TO
LIGHT AMTS SOUTH.
TEMPERATURES WILL BE HELD IN CHECK EARLY TODAY WITH ABUNDANT AMOUNTS
OF CLOUDS EARLY. WE WENT WITH MOSTLY MAV MOS AND OFFERED LOW 80S
OVER MOST AREAS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
WE WILL CONTINUE IN THE WARM SECTOR TONIGHT WITH THE UPPER FLOW
BECOMING A BIT MORE SWRLY ALOFT. A COLD FRONT WILL BE SLOWING ITS
APPROACH INTO WRN NY AND WRN PA. SHOWERS AND SCT THUNDERSTORMS WILL
CONTINUE FROM THE LATE AFTERNOON INTO THE EARLY OVERNIGHT PERIODS.
THE AREAS NORTH/WEST WILL HAVE THE BETTER CHCS FOR THE RAINS. WE
WILL CARRY THE LIKELY POPS INTO THE OVERNIGHT NORTH/WEST AND HOLD
THE HIGHER CHC POPS SOUTH/EAST. QPF...1/2 INCH NORTH 1/10 INCH
SOUTH.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AN AREA OF LOW PRESSURE IN SERN CANAD WILL WORK ITS WAY EWD. AS IT
DOES A CDFNT WILL CROSS THE AREA FROM W TO E ON FRI INTO FRI
NIGHT. THE LATEST MDL GUID CURRENTLY INDICATES THAT THE FRI
DAYTIME PD COULD BE FAIRLY WET, FOR AT LEAST A PORTION OF THE
AREA, AND THERE COULD BE LOCALIZED CONVECTION WHICH COULD MAKE FOR
PDS OF HEAVY RAIN. IT IS PSBL, IF THE MDLS CONTINUE TO AGREE ON A
LOCATION AS THEY ARE NOW (N AND W) THAT A FFA MAY BE NEEDED AS
RNFL AMTS APPEAR TO BE AOA 1 INCH. THE FRONT SHUD CLEAR THE AREA
DURG THE OVERNIGHT HOURS ON FRI AND CLEARING WILL OCCUR FROM N TO
S. PRECIP MAY LINGER ACRS THE DELMARVA INTO ERLY SAT. THE ECMWF
DOES CLEAR THINGS OUT FASTER THAN THE GFS. BOTH MDLS KEEP THE
FRONT CLOSE BY, SO IT WON`T TAKE MUCH IN THE WAY OF A PERTURBATION
FOR IT TO BRING ANOTHER SHOT OF PRECIP, BUT FOR BOTH MDLS DRY
THINGS OUT BY LATER SAT AT THE LATEST, AS HIGH PRESSURE BUILDS IN.
SUN THEN LOOKS DRY. MUCH LESS CONFIDENCE INTO MON AS THE GFS WANTS
TO BRING A WAVE ACRS THE STALLED FRONT, WHICH WOULD BRING PRECIP,
MAINLY ACRS THE S. THE ECMWF IS DRY DURG THIS TIME. THE CMC ALSO
HAS A WAVE ON MON, BUT ITS OVERALL SYNOPTIC PATN IS A BUT SUSPECT
OVERALL. BY TUE, THE MDLS BRING ANOTHER LOW TO THE N AND ANOTHER
CDFNT ACRS THE REGION, AND ANOTHER CHC OF RAIN.
THIS IS A LOW CONFIDENCE FCST FOR THE EARLY PORTION OF NEXT WEEK
AS IT WILL BE DEPENDENT ON THE POSN OF THE FRONT AND IF ANY WAVES
DEVELOP ALG IT AND WHERE THEY MOVE. BASED ON THE ECMWF`S GENLY
SUPERIOR PERFORMANCE, WANT TO GIVE IT A BIT OF A NOD, BUT CAN`T
RULE OUT A MORE PESSIMIST SOLN EITHER. FOR NOW, WILL BRING IN LOW
POPS MON, LOW CHC POPS ON TUE TO SEE HOW THINGS PLAY OUT AND THEN
A DRY FCST ON WED AS HIGH PRESSURE BUILDS IN.
TEMPS WILL GENLY BE AT OR SLIGHTLY ABV NRML THRU THE PD.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...IMPROVING CIGS WITH BREAKS IN THE CLOUDS AND SLOW MIXING
OUT OF ANY LIGHT FOG THIS MORNING...THEN SCT SHOWERS/TSTMS OCCUR
LATER TODAY. LOWER CONDITIONS WITH THE CONVECTION. THE PROB30 FROM
EARLIER WAS RETAINED IN THE 06Z TAFS...WE`LL DECIDE LATER WHAT TO
DO FOR THE 12Z TAFS...SINCE THE 9 HOUR WINDOW OF `NO PROB30S` WILL
BE OPEN AT THAT POINT.
TONIGHT...SHOWERS/TSTMS GRADUALLY ENDING. LOWER CIGS/VSBYS AGAIN
INDICTED IN THE GUIDANCE MVFR?...IFR? LOW CONFID OVERALL.
OUTLOOK...
FRIDAY THROUGH EARLY MORNING SATURDAY...MAINLY MVFR OR IFR
CONDITIONS EXPECTED IN SHOWERS AND PSBL TSTMS. SOME HVY RAIN PSBL.
MDT CONFIDENCE.
REMAINDER OF SATURDAY THROUGH MONDAY...MOSTLY VFR CONDITIONS.
ISOLATED SHWRS/TSTMS REMAIN POSSIBLE, ESPECIALLY MON. SUN SHOULD
BE DRY. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
A MODERATE SOUTH WIND CONTINUES ACROSS THE OCEAN WATERS AND MORE OF
A SWLY WIND ACROSS DEL BAY. OVERALL...THE WIND SPEEDS AND SEAS WILL
REMAIN BELOW SCA CRITERIA TODAY AND TONIGHT. A FEW WIND GUSTS TO 25
KTS MAY OCCUR EARLY THIS MORNING AND LATER TONIGHT...BUT THEY WILL
NOT PERSIST. THE MAIN MARINE HAZARD TODAY AND TONIGHT WOULD BE ANY
GUSTY WINDS ASSD WITH TSTMS WHICH WILL BE AROUND EARLY THIS
MORNING...THIS AFTERNOON AND TONIGHT. SEAS...ON THE OCEAN 3-4 FT AND
DEL BAY 1-2 FT (NORTH) AND 2-3FT (SOUTH).
OUTLOOK...
OVERALL, SUB-SCA CONDITIONS ARE EXPECTED FOR OUR AREA WATERS THROUGH
THE BULK OF THE OUTLOOK PERIOD. GUIDANCE IS SHOWING AN INCREASE IN
THE SOUTHERLY TO SOUTHWESTERLY FLOW DURING FRIDAY AHEAD OF AN
APPROACHING CDFNT. THE WIND CUD GUST TO AROUND 20 KTS OR SO AS
WELL DURG THIS TIME. IN ADDITION, WAVEWATCH GUIDANCE ALSO INDICATES
SEAS RISING TO AROUND 5 OR PSBLY 6 FEET FOR OUR COASTAL WATERS
DURING THIS TIMEFRAME. HOWEVER, THIS GUIDANCE TENDS TO RUN A
LITTLE HIGH IN SOUTHERLY FLOW, AND CONFIDENCE IS BELOW AVERAGE. SO
WILL CONTINUE TO MONITOR FOR ANY PSBL FLAGS. SEAS SHOULD THEN
LOWER BEHIND THE CFP INTO THE WEEKEND, AS WINDS SHIFT TO THE NW.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI/O`HARA
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...NIERENBERG/O`HARA
MARINE...NIERENBERG/O`HARA
AREA FORECAST DISCUSSION
NWS BOISE ID
950 AM MDT THU AUG 8 2013
.DISCUSSION...SPEED MAX MOVING NORTH ON THE EAST SIDE OF THE UPPER
LOW IS EVIDENT IN FAR NE CA AS OF 930 AM MDT. THIS IS ALREADY
HELPING TO INITIATE AND STRENGTHEN CONVECTION IN SE OREGON...AND
THE EFFECT IS GOING TO BE FELT EVEN IN OUR SW IDAHO ZONES. AS WE
HEAT UP TODAY...WE EXPECT SCATTERED SHOWERS AND THUNDERSTORMS
OVER A LARGE PORTION OF THE CWA. RED FLAG WARNINGS ARE STILL IN
EFFECT FOR MUCH OF THE AREA. LATEST HRRR OUTPUT HAS BEEN
CONSISTENT IN BRINGING CONVECTION EVEN INTO THE VALLEYS...SO HAVE
SLIGHTLY RAISED POPS IN THE LOWER ELEVATIONS FOR THIS AFTERNOON.
CONCERNING TOMORROW...THE DRY SLOT APPEARS HEADED MAINLY FOR THE
IDAHO SIDE OF OUR CWA. WE HAVE ALREADY UPDATED POP GRIDS TO TAKE
THIS INTO ACCOUNT FOR FRIDAY...AND MAY TWEAK THEM A BIT MORE THIS
AFTERNOON BEFORE THE FINAL PACKAGE COMES OUT. ANOTHER UPDATE WILL
BE DONE SHORTLY.
&&
.AVIATION...VFR. THIS MORNING...SCATTERED TO BROKEN MID LEVEL
CLOUDS AND ISOLATED SHOWERS. THIS AFTERNOON THROUGH TONIGHT...
ISOLATED THUNDERSTORMS OVER THE WEST CENTRAL IDAHO AND BOISE
MOUNTAINS. SCATTERED THUNDERSTORMS ACROSS EASTERN OREGON AND
SOUTHWEST IDAHO SOUTH OF THE SNAKE RIVER VALLEY. SURFACE WINDS...
LIGHT THIS MORNING THEN NORTH TO NORTHWEST 5-15 KTS THIS AFTERNOON
AND TONIGHT. LOCAL GUSTY WINDS NEAR THUNDERSTORMS. WINDS ALOFT...
NORTHEAST TO SOUTHEAST AROUND 10 KTS.
&&
.PREV DISCUSSION...
SHORT TERM...TODAY THROUGH FRIDAY...UPPER LOW OFF THE NORTHERN
CALIFORNIA COAST WILL MOVE LITTLE THROUGH FRIDAY AS IT MEANDERS
OFFSHORE. LATEST SATELLITE IMAGERY REVEALS PARTLY TO MOSTLY CLOUDY
SKIES ACROSS SE OREGON AND SW IDAHO...BUT RADAR RETURNS ONLY SHOWED
ISOLATED SHOWERS ACROSS PORTIONS OF SE OREGON AND IN SW IDAHO SOUTH
OF THE SNAKE RIVER. THERE HAS NOT BEEN LIGHTNING FOR SEVERAL HOURS
AND EXPECT ONLY ISOLATED SHOWERS THIS MORNING. SHORTWAVES ROTATING
THROUGH THE REGION ASSOCIATED WITH UPPER LOW...COMBINED WITH
INSTABILITY FROM DAYTIME HEATING...WILL SUPPORT ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. THE COVERAGE WILL BE
GREATER THAN WEDNESDAY IN SW IDAHO...ESPECIALLY IN THE HIGHER
TERRAIN...DUE TO AN INCREASE IN MOISTURE. THERE WILL ALSO BE ANOTHER
ROUND OF SCATTERED THUNDERSTORMS IN SE OREGON THIS AFTERNOON.
CONVECTION WILL REMAIN ACTIVE THIS EVENING THEN GRADUALLY DIMINISH
OVERNIGHT. MODELS SHOW THE MOST ACTIVE AREA WILL BE ACROSS SE OREGON
WITH CONVECTION LINGERING INTO FRIDAY MORNING AS MORE SHORT WAVES
PIVOT AROUND THE UPPER LOW. MEANWHILE...MUCH DRIER AIR OVER SOUTHERN
NEVADA WILL MOVE NORTHWARD AND REACH PORTIONS OF SW IDAHO ON FRIDAY.
POPS MAY NEED TO BE TRIMMED LOWER IF THIS MODEL TREND CONTINUES. IN
THE MEANTIME...WILL KEEP GENERALLY ISOLATED POPS ACROSS THE HIGHER
TERRAIN WITH NO MENTION OF CONVECTION IN THE SW IDAHO VALLEYS.
CHANCE OF SHOWERS/THUNDERSTORMS WILL CONTINUE IN SE OREGON INTO THE
AFTERNOON DUE TO THE CLOSER PROXIMITY TO THE LOW. TEMPERATURES WILL
BE A FEW DEGREES LOWER TODAY AND FRIDAY...ALTHOUGH STILL A LITTLE
ABOVE NORMAL. NO SIGNIFICANT WINDS ARE FORECAST...EXCEPT LOCALLY
STRONG WIND GUSTS WILL ACCOMPANY THE THUNDERSTORMS.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...LITTLE CHANGE IN THE
WEATHER PATTERN AS A CLOSED UPPER LEVEL LOW WILL BE OVER NORTHERN
CALIFORNIA FRIDAY NIGHT AND THEN SLOWLY LIFT TO THE NORTH ALONG THE
WEST COAST SATURDAY THROUGH MONDAY NIGHT AND THEN REMAIN NEARLY
STATIONARY JUST OFF THE WEST COAST OF WASHINGTON TUESDAY THROUGH
WEDNESDAY. WITH THE LOW SHIFTING TO THE NORTH PRECIPITATION
ASSOCIATED WITH THIS LOW WILL ALSO SHIFT TO NORTHERN ZONES AND
DECREASE TO A SLIGHT CHANCE. TEMPERATURES THROUGH THE EXTENDED
PERIOD WILL REMAIN A FEW DEGREES ABOVE NORMAL.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...RED FLAG WARNING UNTIL 6 AM MDT FRIDAY IDZ402-403-421-426.
RED FLAG WARNING UNTIL MIDNIGHT MDT FRIDAY NIGHT IDZ423.
OR...RED FLAG WARNING UNTIL MIDNIGHT MDT /11 PM PDT/ FRIDAY NIGHT
ORZ636-637.
&&
$$
WEATHER.GOV/BOISE
DISCUSSION...SP
AVIATION.....JT
PREV SHORT TERM...BW
PREV LONG TERM....JA
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1032 AM EDT THU AUG 8 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 210 AM EDT THU AUG 8 2013
WARM AND HUMID AIR WILL REMAIN OVER INDIANA FOR THE NEXT FEW DAYS
AS A FRONTAL BOUNDARY LINGERS ACROSS SOUTHERN INDIANA. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH FRIDAY NIGHT AS
SEVERAL UPPER LEVEL WEATHER DISTURBANCES PUSH INTO THE OHIO VALLEY.
DRY AND LESS HUMID WEATHER WILL ARRIVE SATURDAY AS HIGH PRESSURE
FROM CANADA BUILDS ACROSS THE REGION.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT THU AUG 8 2013
LOW STRATUS STUBBORNLY HANGING ON ACROSS A GOOD PORTION OF THE
FORECAST AREA...WITH CLOUDS HAVING ACTUALLY INCREASED IN COVERAGE
OVER NORTHERN COUNTIES SINCE 12Z. SCATTERED CONVECTION HAS ALSO
DEVELOPED OVER THE NORTHERN WABASH VALLEY OVER THE LAST HOUR OR
SO. 13Z SURFACE ANALYSIS PLACES THE WEAK REMNANT BOUNDARY ACROSS
THE FORECAST AREA...ROUGHLY EXTENDING FROM NEAR RICHMOND W/SW TO
JUST SOUTH OF THE INDY METRO AND KHUF. MUGGY MORNING WITH TEMPS
MAINLY IN THE 70S.
COMPLEX FORECAST FOR THE REMAINDER OF THE DAY AS CONVECTION HAS
DEVELOPED SOONER THAN ANTICIPATED. VERY WEAK FORCING ALOFT WITHIN
A POORLY DEFINED UPPER TROUGH COMBINED WITH AN AREA OF LOW LEVEL
MOISTURE CONVERGENCE APPEAR TO BE CONTRIBUTING TO THE CONVECTIVE
DEVELOPMENT NORTHWEST OF INDY THIS MORNING. HRRR GUIDANCE IS
CAPTURING THIS TO SOME DEGREE...AND TRENDS TOWARDS FURTHER
CONVECTIVE DEVELOPMENT ACROSS THE FORECAST AREA INTO THE
AFTERNOON. CONSIDERING INCREASING INSTABILITY OVER THE NEXT FEW
HOURS COMBINED WITH THE DEEP LOW LEVEL MOISTURE PRESENT...WEAK
FORCING ALOFT AND THE PRESENCE OF THE BOUNDARY ACROSS THE
REGION...REALLY HARD TO ARGUE WITH THIS SCENARIO AT THIS POINT.
BUMPED UP POPS TO BEGIN NORTHWEST OF INDY NOW...THEN INCREASE TO
30-50 POPS OVER ENTIRE FORECAST AREA FOR THE AFTERNOON. MENTIONING
ONLY ISOLATED THUNDER THROUGH MIDDAY AS MESOANALYSIS SHOWS LITTLE
INSTABILITY PRESENT RIGHT NOW. EXPECT A BETTER CHANCE FOR THUNDER
THIS AFTERNOON AS INSTABILITY INCREASES WITH DIURNAL HEATING.
WHILE THERE ARE BREAKS IN THE CLOUD COVER THIS MORNING...
ESPECIALLY OVER SOUTHERN COUNTIES...HAVE INCREASED CLOUD COVERAGE
FOR THE AFTERNOON AS CU LIKELY TO FILL IN AS CONVECTIVE TEMPS ARE
MET. ADDITIONALLY...CLOUD DEBRIS FROM WEAKENING MCS OVER THE
OZARKS POISED TO EXPAND INTO THE REGION THIS AFTERNOON. WITH THE
INCREASE IN CLOUDS...DROPPED HIGH TEMPS A COUPLE DEGREES AS WELL.
ZONE AND GRID UPDATES OUT SHORTLY.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 210 AM EDT THU AUG 8 2013
LITTLE CHANGE APPEARS IN THE OVERALL PATTERN THROUGH FRIDAY
AFTERNOON. GFS AND NAM CONTINUE TO SUGGEST WEAK...POORLY ORGANIZED
SHORT WAVES PUSHING THROUGH THE FLOW ALOFT. MEANWHILE THE FRONTAL
BOUNDARY LINGERS NEAR THE OHIO VALLEY. 310K GFS ISENTROPIC SURFACE
FAILS TO SHOW MUCH IN THE WAY OF LIFT...BUT DOES MANAGE TO
ILLUSTRATE THE VERY MOIST AIR MASS ACROSS THE AREA SHOWING
SPECIFIC HUMIDITIES IN EXCESS OF 4 G/KG ON FRIDAY. FORECAST
SOUNDINGS THROUGH FRIDAY SHOW LESS FAVORABLE LAPSE RATES WITH
LESS CAPE THAN TODAY. HOWEVER WITH THE MOIST FLOW ALOFT...MOIST
AIR IN PLACE AT THE SURFACE AND UNCERTAINTY REMAINING WITH ANY
EMBEDDED SHORT WAVES WILL CONTINUE TO KEEP LOW CHC POPS TONIGHT
AND AGAIN ON FRIDAY. WILL TREND LOWS WARMER THAN MAVMOS AND STICK
CLOSE ON HIGHS FOR FRIDAY.
ON FRIDAY NIGHT THE GFS AND NAM BOTH SUGGEST A STRONG SHORT WAVE
ALOFT SWEEPING THROUGH THE FLOW. TIME HEIGHT SECTIONS BEGIN TO
SHOW MORE VV WHILE THE NAM SOUNDINGS SHOW DEEP SATURATION. THE GFS
IS MUCH LESS AGGRESSIVE WITH SATURATION...BUT STILL DOES SHOW THE
MAIN WAVE ALOFT. MEANWHILE GFS 310K ISENTROPIC SURFACE SHOWS
MINIMAL LIFT...BUT A VERY MOIST AIR MASS IN PLACE WITH SPECIFIC
HUMIDITIES OVER 5 G/KG AGAIN. IN THE LOWER LEVELS...BEST
CONVERGENCE REMAINS NEAR THE FRONT...LINGERING NEAR THE OHIO
RIVER. THUS WILL USE A BLEND OF THE LOW GFS POPS AND THE HIGHER
NAM POPS FOR FRIDAY NIGHT.
A MUCH DIFFERENT AIR MASS ARRIVES ON SATURDAY AND SATURDAY NIGHT
AS HIGH PRESSURE BUILDS ACROSS THE AREA FROM CANADA. FORECAST
SOUNDINGS AGREE AS THE COLUMN DRIES OUT DRAMATICALLY AMID
SUBSIDENCE. CONVECTIVE TEMPERATURES LOOK QUITE REACHABLE WITH A
MID LEVEL CAP IN PLACE...THUS EXPECTED SOME AFTERNOON CU ON
SATURDAY AND MOSTLY CLEAR SKIES THAT NIGHT. GIVEN THE FORECAST
SOUNDINGS WILL TREND HIGHS ON SATURDAY COOLER THAN MAVMOS AND
STICK CLOSE ON LOWS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ISSUED AT 230 AM EDT THU AUG 8 2013
LONG TERM PERIOD CONTINUES TO BE CHARACTERIZED BY ZONAL TO
MODERATELY CYCLONIC FLOW...SUGGESTING TEMPERATURES NEAR TO A FEW
DEGREES BELOW NORMAL. INITIALIZATION HANDLES THIS WELL AND FEW
CHANGES REQUIRED.
DID CONFINE ONLY SLIGHT CHANCE POPS TO MONDAY AS GFS SUGGESTS A
WEAK FRONTAL PASSAGE WHICH COULD POP A SHOWER OR ISOLATED STORM.
BEYOND MONDAY...IN OTHER PERIODS POPS ARE NOT MERITED...AND WERE
REMOVED.
&&
.AVIATION /DISCUSSION FOR THE 081500Z TAF UPDATE/...
ISSUED AT 1032 AM EDT THU AUG 8 2013
LOW LEVEL STRATUS HAS BROKEN UP...BUT ADDITIONAL CLOUDS AROUND
5000FT HAVE DEVELOPED. A WEAK SURFACE TROUGH WILL CONTINUE TO
MEANDER NEAR KIND FOR THE NEXT FEW HOURS...KEEPING WINDS VARIABLE IN
DIRECTION. SCATTERED SHOWERS WILL CONTINUE TO POP-UP AS WELL...SO
ADDED VCSH. CANNOT RULE OUT MVFR CONDITIONS IN SHOWERS.
PREVIOUS DISCUSSION FOLLOWS...
SO FAR THIS MORNING...IND HAS MADE IT TO IFR BUT OTHER SITES HAVE
ONLY FLIRTED WITH MVFR. ANY RESTRICTIONS SHOULD END BY MID
MORNING...WITH BROKEN VFR STRATOCU REPLACING THEM.
CANNOT ENTIRELY RULE OUT A FEW SHOWERS OR STORMS TODAY...BUT WITH
MAJOR UNCERTAINTY IN TIMING AND PLACEMENT...CANNOT MENTION RIGHT NOW.
LATE IN THE PERIOD...GUIDANCE WANTS TO REDEVELOP
RESTRICTIONS...QUITE LOW IN SOME SPOTS. LAMP WAS SIGNIFICANTLY
OVERAGGRESSIVE TONIGHT...SO WILL LEAVE ANY MENTION OF RESTRICTIONS
OUT FOR NOW EXCEPT AT BMG...WHICH IS ONE OF THE FOGGIER SITES AND
WILL BE A BIT CLOSER TO THE BOUNDARY AND IN A SLIGHTLY RICHER
AIRMASS.
WINDS WILL BE BELOW 10KT THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...NIELD/50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1003 AM EDT THU AUG 8 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 210 AM EDT THU AUG 8 2013
WARM AND HUMID AIR WILL REMAIN OVER INDIANA FOR THE NEXT FEW DAYS
AS A FRONTAL BOUNDARY LINGERS ACROSS SOUTHERN INDIANA. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH FRIDAY NIGHT AS
SEVERAL UPPER LEVEL WEATHER DISTURBANCES PUSH INTO THE OHIO VALLEY.
DRY AND LESS HUMID WEATHER WILL ARRIVE SATURDAY AS HIGH PRESSURE
FROM CANADA BUILDS ACROSS THE REGION.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT THU AUG 8 2013
LOW STRATUS STUBBORNLY HANGING ON ACROSS A GOOD PORTION OF THE
FORECAST AREA...WITH CLOUDS HAVING ACTUALLY INCREASED IN COVERAGE
OVER NORTHERN COUNTIES SINCE 12Z. SCATTERED CONVECTION HAS ALSO
DEVELOPED OVER THE NORTHERN WABASH VALLEY OVER THE LAST HOUR OR
SO. 13Z SURFACE ANALYSIS PLACES THE WEAK REMNANT BOUNDARY ACROSS
THE FORECAST AREA...ROUGHLY EXTENDING FROM NEAR RICHMOND W/SW TO
JUST SOUTH OF THE INDY METRO AND KHUF. MUGGY MORNING WITH TEMPS
MAINLY IN THE 70S.
COMPLEX FORECAST FOR THE REMAINDER OF THE DAY AS CONVECTION HAS
DEVELOPED SOONER THAN ANTICIPATED. VERY WEAK FORCING ALOFT WITHIN
A POORLY DEFINED UPPER TROUGH COMBINED WITH AN AREA OF LOW LEVEL
MOISTURE CONVERGENCE APPEAR TO BE CONTRIBUTING TO THE CONVECTIVE
DEVELOPMENT NORTHWEST OF INDY THIS MORNING. HRRR GUIDANCE IS
CAPTURING THIS TO SOME DEGREE...AND TRENDS TOWARDS FURTHER
CONVECTIVE DEVELOPMENT ACROSS THE FORECAST AREA INTO THE
AFTERNOON. CONSIDERING INCREASING INSTABILITY OVER THE NEXT FEW
HOURS COMBINED WITH THE DEEP LOW LEVEL MOISTURE PRESENT...WEAK
FORCING ALOFT AND THE PRESENCE OF THE BOUNDARY ACROSS THE
REGION...REALLY HARD TO ARGUE WITH THIS SCENARIO AT THIS POINT.
BUMPED UP POPS TO BEGIN NORTHWEST OF INDY NOW...THEN INCREASE TO
30-50 POPS OVER ENTIRE FORECAST AREA FOR THE AFTERNOON. MENTIONING
ONLY ISOLATED THUNDER THROUGH MIDDAY AS MESOANALYSIS SHOWS LITTLE
INSTABILITY PRESENT RIGHT NOW. EXPECT A BETTER CHANCE FOR THUNDER
THIS AFTERNOON AS INSTABILITY INCREASES WITH DIURNAL HEATING.
WHILE THERE ARE BREAKS IN THE CLOUD COVER THIS MORNING...
ESPECIALLY OVER SOUTHERN COUNTIES...HAVE INCREASED CLOUD COVERAGE
FOR THE AFTERNOON AS CU LIKELY TO FILL IN AS CONVECTIVE TEMPS ARE
MET. ADDITIONALLY...CLOUD DEBRIS FROM WEAKENING MCS OVER THE
OZARKS POISED TO EXPAND INTO THE REGION THIS AFTERNOON. WITH THE
INCREASE IN CLOUDS...DROPPED HIGH TEMPS A COUPLE DEGREES AS WELL.
ZONE AND GRID UPDATES OUT SHORTLY.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 210 AM EDT THU AUG 8 2013
LITTLE CHANGE APPEARS IN THE OVERALL PATTERN THROUGH FRIDAY
AFTERNOON. GFS AND NAM CONTINUE TO SUGGEST WEAK...POORLY ORGANIZED
SHORT WAVES PUSHING THROUGH THE FLOW ALOFT. MEANWHILE THE FRONTAL
BOUNDARY LINGERS NEAR THE OHIO VALLEY. 310K GFS ISENTROPIC SURFACE
FAILS TO SHOW MUCH IN THE WAY OF LIFT...BUT DOES MANAGE TO
ILLUSTRATE THE VERY MOIST AIR MASS ACROSS THE AREA SHOWING
SPECIFIC HUMIDITIES IN EXCESS OF 4 G/KG ON FRIDAY. FORECAST
SOUNDINGS THROUGH FRIDAY SHOW LESS FAVORABLE LAPSE RATES WITH
LESS CAPE THAN TODAY. HOWEVER WITH THE MOIST FLOW ALOFT...MOIST
AIR IN PLACE AT THE SURFACE AND UNCERTAINTY REMAINING WITH ANY
EMBEDDED SHORT WAVES WILL CONTINUE TO KEEP LOW CHC POPS TONIGHT
AND AGAIN ON FRIDAY. WILL TREND LOWS WARMER THAN MAVMOS AND STICK
CLOSE ON HIGHS FOR FRIDAY.
ON FRIDAY NIGHT THE GFS AND NAM BOTH SUGGEST A STRONG SHORT WAVE
ALOFT SWEEPING THROUGH THE FLOW. TIME HEIGHT SECTIONS BEGIN TO
SHOW MORE VV WHILE THE NAM SOUNDINGS SHOW DEEP SATURATION. THE GFS
IS MUCH LESS AGGRESSIVE WITH SATURATION...BUT STILL DOES SHOW THE
MAIN WAVE ALOFT. MEANWHILE GFS 310K ISENTROPIC SURFACE SHOWS
MINIMAL LIFT...BUT A VERY MOIST AIR MASS IN PLACE WITH SPECIFIC
HUMIDITIES OVER 5 G/KG AGAIN. IN THE LOWER LEVELS...BEST
CONVERGENCE REMAINS NEAR THE FRONT...LINGERING NEAR THE OHIO
RIVER. THUS WILL USE A BLEND OF THE LOW GFS POPS AND THE HIGHER
NAM POPS FOR FRIDAY NIGHT.
A MUCH DIFFERENT AIR MASS ARRIVES ON SATURDAY AND SATURDAY NIGHT
AS HIGH PRESSURE BUILDS ACROSS THE AREA FROM CANADA. FORECAST
SOUNDINGS AGREE AS THE COLUMN DRIES OUT DRAMATICALLY AMID
SUBSIDENCE. CONVECTIVE TEMPERATURES LOOK QUITE REACHABLE WITH A
MID LEVEL CAP IN PLACE...THUS EXPECTED SOME AFTERNOON CU ON
SATURDAY AND MOSTLY CLEAR SKIES THAT NIGHT. GIVEN THE FORECAST
SOUNDINGS WILL TREND HIGHS ON SATURDAY COOLER THAN MAVMOS AND
STICK CLOSE ON LOWS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
ISSUED AT 230 AM EDT THU AUG 8 2013
LONG TERM PERIOD CONTINUES TO BE CHARACTERIZED BY ZONAL TO
MODERATELY CYCLONIC FLOW...SUGGESTING TEMPERATURES NEAR TO A FEW
DEGREES BELOW NORMAL. INITIALIZATION HANDLES THIS WELL AND FEW
CHANGES REQUIRED.
DID CONFINE ONLY SLIGHT CHANCE POPS TO MONDAY AS GFS SUGGESTS A
WEAK FRONTAL PASSAGE WHICH COULD POP A SHOWER OR ISOLATED STORM.
BEYOND MONDAY...IN OTHER PERIODS POPS ARE NOT MERITED...AND WERE
REMOVED.
&&
.AVIATION /DISCUSSION FOR THE 08/12Z TAFS/...
ISSUED AT 705 AM EDT THU AUG 8 2013
SO FAR THIS MORNING...IND HAS MADE IT TO IFR BUT OTHER SITES HAVE
ONLY FLIRTED WITH MVFR. ANY RESTRICTIONS SHOULD END BY MID
MORNING...WITH BROKEN VFR STRATOCU REPLACING THEM.
CANNOT ENTIRELY RULE OUT A FEW SHOWERS OR STORMS TODAY...BUT WITH
MAJOR UNCERTAINTY IN TIMING AND PLACEMENT...CANNOT MENTION RIGHT NOW.
LATE IN THE PERIOD...GUIDANCE WANTS TO REDEVELOP
RESTRICTIONS...QUITE LOW IN SOME SPOTS. LAMP WAS SIGNIFICANTLY
OVERAGGRESSIVE TONIGHT...SO WILL LEAVE ANY MENTION OF RESTRICTIONS
OUT FOR NOW EXCEPT AT BMG...WHICH IS ONE OF THE FOGGIER SITES AND
WILL BE A BIT CLOSER TO THE BOUNDARY AND IN A SLIGHTLY RICHER
AIRMASS.
WINDS WILL BE BELOW 10KT THROUGHOUT THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM....NIELD
AVIATION...NIELD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS WICHITA KS
708 AM CDT THU AUG 8 2013
UPDATED 12Z AVIATION SECTION.
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
TODAY & TONIGHT:
AS ALL OBVIOUSLY KNOW...FLOODING TO CONTINUE BEINGING THE HIGHLIGHT OF
FOR PERIODS AS FLOOD WATCH REMAINS IN EFFECT TIL 7 AM FRIDAY.
DURING THE NIGHT A POORLY-DEFINED STATIONARY FRONT WAS DRAPED IN AN E-W
MANNER GENERALLY THROUGH CNTRL OK WITH A WEAK 700-MB TROF SITUATED FROM
THE UT/CO BORDER TO ~CA/AZ BORDER. WITH THE TROF SLOWLY EVOLVING INTO A
WEAK LOW AS IT VENTURES E TO WRN KS RICH & DEEP MOISTURE WILL CONTINUE
TO SPREAD NE ACROSS KS. WITH THE MID-LVL "KICKER" LACKING THE SFC-850MB
FRONTS WILL MOVE VERY LITTLE...IF AT ALL...THEREBY PROMOTING BROAD ECHO
TRAINING OVER KICT COUNTRY WHICH IN TURN WOULD EXACERBATE THE FLOODING
SITUATION ACROSS THE CWA. ONLY CHANGES TO INHERITED FORECAST WERE TO
SHIFT THE POP GRADIENT TO GENERALLY A N/S ORIENTATION TO BETTER ALIGN
WITH THE BROAD LWR-MID DECK MOISTURE CHANNEL. ASSIGNED 80-100% TO CNTRL
& SC KS THIS MORNING WITH HIGHEST POPS & ASSOCIATED TSRA SHIFTED E OVER
SE KS THIS AFTERNOON AS HRRR DEPICTS. PW`S REMAIN IN 175-200% RANGE SO
CONTINUED TO HIT QPFS HARD.
FRI & FRI NIGHT:
A FAIRLY BROAD UPR-DECK RIDGE IS FORECAST MOVE SLOWLY MOVG E TOWARD THE
CNTRL ROCKIES...THE WEAK MID-LVL LOW WILL GET FORCED E TOWARD...THEN
ACROSS...ERN KS. THIS WOULD THEREFORE SHIFT BULK OF +TSRA E ACROSS THE
KS/MO BORDER ON FRI WITH -TSRA CONFINED FROM GENERALLY THE FLINT HILLS
E FRI NGT. AS SUCH WILL CONTINUE TO SCHEDULE THE FLOOD WATCH TO END AT
7AM FRI.
SAT & SAT NGT:
MOST AREAS WILL EXPERIENCE AN INTERMISSION FROM TSRA. A FEW TSRA SHOULD
VENTURE TOWARD THE WRN CORRIDOR SAT NGT AS WEAK LWR-DECK TROFFING
BEGINS ALONG THE FRONT RANGE.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
ALL AREAS TO BE UNDER A WEAK NW FLOW REGIME FOR MOST OF THESE PERIODS.
A WEAK COLD FRONT WILL VENTURE SE TOWARD & PERHAPS ACROSS KICGT COUNTRY
EARLY NEXT WEEK WHICH WOULD INCREASE TSRA CHANCES FOR MUCH OF THESE
PERIODS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 706 AM CDT THU AUG 8 2013
LARGE MESOSCALE CONVECTIVE SYSTEM (MCS)CONTINUES TO MAKE SLOW
PROGRESS ACROSS THE ERN HALF OF KS AT THIS TIME. THIS WILL LEAD TO
MVFR VSBYS WITH SHRA/VCTS FOR MOST TAF SITES UNTIL 15-16Z. AFTER
THIS MCS MOVES EAST...WILL SEE SOME MID LEVEL CLOUDS AT 4K FEET HAND
AROUND FOR THE AFTERNOON HOURS.
SHOWERS/STORMS COULD REDEVELOP AND BECOME FAIRLY WIDESPREAD LATE
THIS EVENING INTO THE OVERNIGHT...ESPECIALLY ACROSS SRN KS. COULD
SEE SOME VSBY/CIG REDUCTIONS INTO AT LEAST THE MVFR RANGE AT TIMES
OVERNIGHT.
KETCHAM
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 80 68 79 65 / 100 90 40 10
HUTCHINSON 78 65 76 63 / 100 90 40 10
NEWTON 78 66 76 63 / 100 90 50 10
ELDORADO 79 67 79 64 / 100 90 50 20
WINFIELD-KWLD 82 70 82 66 / 100 70 30 10
RUSSELL 77 63 76 62 / 100 70 40 10
GREAT BEND 77 63 75 61 / 100 80 40 10
SALINA 78 65 77 63 / 100 80 50 10
MCPHERSON 78 65 76 63 / 100 80 50 10
COFFEYVILLE 85 71 86 68 / 80 80 40 20
CHANUTE 81 69 81 66 / 80 80 60 20
IOLA 80 68 80 66 / 80 80 70 20
PARSONS-KPPF 83 70 84 67 / 80 80 50 20
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY MORNING FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
554 AM MDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 446 AM MDT THU AUG 8 2013
FORECAST CONCERNS WILL BE THREAT OF HEAVY RAINFALL AND CHANCES OF
PRECIPITATION. SATELLITE SHOWING LITTLE CHANGE AS A COMPLEX AND
AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO NORTH AMERICA
REMAINS IN PLACE. COMPLEX AND SLOW MOVING UPPER HAS MOVED INTO
COLORADO AND NEW MEXICO. SEVERAL SHORTWAVE TROUGHS ROTATING AROUND
THIS MAIN SYSTEM. AIR MASS REMAINS MOIST THROUGH A DEEP LAYER.
PERSISTENT FRONTAL BOUNDARY REMAINS DRAPED TO OUR SOUTH AND WEST.
AT JET LEVEL...THE CANADIAN AND THE UKMET INITIALIZED BEST ON THE
JET THAT IS OVER/NEAR OUR AREA. AT MID LEVELS...SATELLITE AND UPPER
AIR ANALYSIS SHOW THAT THE ECMWF/CANADIAN FOLLOWED BY THE GFS ARE
HANDLING CURRENT SYSTEM THE BEST. SREF AND RUC WERE DOING BEST AT
THE SURFACE.
COMPLICATED AND DIFFICULT PRECIPITATION FORECAST MADE MORE DIFFICULT
BY THE FACT THAT MOST IF NOT ALL THE MODEL OUTPUT HAS CURRENT
PRECIPITATION SHIELD TOO FAR SOUTH AND IS BASICALLY IGNORING IT.
TODAY/TONIGHT...WEAK RIGHT REAR QUADRANT OF THE UPPER JET REMAINS
OVER THE AREA FOR MOST OF THE DAY. MODELS ARE IN A LITTLE MORE
DISAGREEMENT ON HOW FAST TO MOVE THIS SEGMENT EAST. ALTHOUGH THE
GENERAL TREND IS TO HAVE THIS SLOWER/FURTHER WEST THAN THE PREVIOUS
TWO DAYS. THE SLOWEST OF THE MODELS DO NOT TAKE THIS RIGHT REAR
QUADRANT TO THE EAST OF THE FORECAST AREA UNTIL BETWEEN 06Z AND 12Z.
BASED ON CURRENT SATELLITE...LATEST ECMWF IS CATCHING THE POSITION
AND COMPLEXITY OF THE UPPER TROUGH THE BEST. CONSIDERING THE
POSITION OF THE 700 MB LOW CIRCULATION...MODELS INDICATING WARM
ADVECTION/UPGLIDE IN ADVANCE OF IT...PLUS STRONG UPPER DIVERGENCE
INDICATED THE EASTERN PORTION OF THE AREA...BELIEVE THE CURRENT
PRECIPITATION WILL CONTINUE TO MOVE AND DEVELOP AND MAINLY AFFECT
THE EASTERN THIRD TO HALF OF THE FORECAST AREA.
THIS LOOKS TO BE THE BEST AREA FOR MODERATE TO HEAVY RAINFALL TO
CONTINUE THROUGH AT LEAST THIS AFTERNOON. GREELEY AND WALLACE
COUNTIES APPEAR TO BE ON THE EDGE THIS AREA AT THIS TIME. HOWEVER...
BOTH OF THOSE COUNTIES...ESPECIALLY WALLACE...GOT AT LEAST 2 TO 5
INCHES OF RAINFALL LAST. SO BELIEVE CHEYENNE COUNTY COLORADO DID
NOT RECEIVE A LOT OF HEAVY RAINFALL AND DO NOT EXPECT IT TODAY...
REMOVED THEM FROM THE FLASH FLOOD WATCH. KEPT THE REMAINDER IN THE
WATCH AND EXTENDED IT THROUGH THE AFTERNOON HOURS DUE TO THE SLOW
PROGRESSION OF THE SYSTEM ACROSS THE AREA.
QUESTION THEN BECOMES HOW FAR WEST TO BRING THE PRECIPITATION. THE
ECMWF IS SHOWING WRAP AROUND PRECIPITATION AND THE HRRR INDICATING
THE SAME IDEA. VERY INTERESTING OCCURRENCE FOR THIS TIME OF YEAR.
CURRENT RADAR TRENDS WOULD INDICATE THIS IS TAKING PLACE. SO KEPT
HIGHER POPS FURTHER WEST AS A RESULT. OVERALL...IF THE ECMWF IS RIGHT
AND IT IS SUPPORTED BY THE GEFS...THIS RAINFALL...EVEN AFTER THE
INTENSITY LETS UP...WILL BE SLOW TO END AND WILL PROBABLY NOT DO SO
UNTIL LATE TONIGHT. DID NOT INSERT AT THIS TIME BUT FOG WILL BE
POSSIBLE IF RAIN QUITS SOONER AND CLEARING CAN OCCUR.
LOWERED MAXES TODAY DUE TO CONTINUED PRECIPITATION AND THICK CLOUD
COVER.
FRIDAY/FRIDAY NIGHT...INTEREST PATTERN CONTINUES. THE ECMWF SHOWING
IT MORE BUT ALSO INDICATED BY THE OTHER MODELS AND GEFS OUTPUT...
MID LEVEL TROUGH REMAINS NEAR TO OVER THE AREA WITH WHAT LOOKS TO BE
A DECENT AMOUNT OF MOISTURE LEFT. ALSO A LEFT FRONT QUADRANT OF A
SOUTHERN JET BECOMES ESTABLISHED OVER THE AREA...ESPECIALLY THE
SOUTHEAST HALF...BY THE MIDDLE OF THE DAY. THIS CONTINUES TO AFFECT
THE AREA...ESPECIALLY THE SOUTHERN HALF...THROUGH THE ENTIRE NIGHT.
SO INSERTED POPS WITH THE HIGHEST IN THE SOUTHEAST PORTION. WITH
PERSISTENT CLOUD COVER AND UNFAVORABLE SURFACE WINDS...TRENDED
MAXES DOWN A LITTLE. IF ENOUGH CLEARING CAN OCCUR AND WITH THE MOIST
AIR MASS AND WET GROUND IN PLACE...WOULD NOT BE SURPRISED TO SEE FOG
DEVELOP.
SATURDAY/SATURDAY NIGHT...SOME DIFFERENCE IN THE JET STRUCTURE
THROUGH THE DAY. AS A RESULT IT LOOKS LIKE SOME OR MOST OF THE AREA
COULD GET LIFT FROM THE JET IN THE AREA. MID LEVEL RIDGE MOVES A
LITTLE EAST WITH A SHORTWAVE TROUGH APPROACHING FROM THE WEST IN THE
AFTERNOON. LEE TROUGH STRENGTHENS WITH SOUTHERLY WINDS INCREASING.
POSSIBILITY OF SOME SURFACE CONVERGENCE IN THE FAR WEST. SO PUT IN
A SLIGHT CHANCE IN THE FAR WEST.
ABOVE MENTIONED SHORTWAVE TROUGH AND INCREASING MID LEVEL WARM AIR
ADVECTION PATTERN ALONG WITH INCREASING JET LIFT COULD CAUSE SOME
ISOLATED THUNDERSTORMS OVER THE MOST OF THE AREA. SO PULLED THE
SLIGHT CHANCE FURTHER EAST DURING THE NIGHT.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 446 AM MDT THU AUG 8 2013
UPPER PATTERN THIS PERIOD WILL SLOWLY EVOLVE FROM AN ELONGATED
EAST-WEST UPPER HIGH OVER THE SOUTHERN U.S. TO A HIGH CENTERED OVER
NEW MEXICO AND A SUBSEQUENT GRADUAL BUILDING OF HEIGHTS OVER THE
CENTRAL ROCKIES. MEANWHILE...UPPER LOWS WILL REMAIN ANCHORED OFF
THE PAC NW COAST AND NEAR JAMES BAY...RESULTING IN WEAK TO MODERATE
NORTHWEST FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS. A FEW
WEAK SHORT WAVE TROUGHS WILL LIFT OUT OF THE WEST COAST TROUGH AND
RIDE OVER THE TOP OF THE ROCKIES RIDGE...PROVIDING A FEW
OPPORTUNITIES FOR PRECIP NEXT WEEK AS THEY EMERGE ONTO THE PLAINS.
CURRENT GUIDANCE SUGGESTS THE MON-TUE TIME FRAME WILL PROVIDE
SOMEWHAT BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND THIS IS
INDICATED WITH 30-40 POPS COMPARED TO 20 POPS ON REMAINING DAYS.
NORTHWEST FLOW ALOFT WILL BRING A SURFACE CANADIAN AIRMASS DOWN NEXT
WEEK SUGGESTING HIGH TEMPERATURES WILL REMAIN SEASONAL IN THE 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 549 AM MDT THU AUG 8 2013
COMPLEX AND UNCERTAIN SET OF TAFS. MODEL PERFORMANCE HAS BEEN POOR
TONIGHT WITH THE HRRR FINALLY HAVING SOME GLIMMER AS TO WHAT
REALITY IS. AT THIS TIME EXPECT THE WORST CONDITIONS TO BE AT
KGLD. AT KGLD HAVE IFR CONDITIONS DUE TO STRATUS. HOWEVER THAT MAY
LIFT WITH THE APPROACHING OF PRECIPITATION. AS IT STANDS NOW IFR
CEILINGS ARE EXPECTED FOR MOST OF THE PERIOD AT KGLD. RAINFALL
ENDS AT KGLD BY LATE AFTERNOON INTO EARLY EVENING WITH FOG THEN
DEVELOPING. VFR CONDITIONS ARE EXPECTED AT KMCK UNTIL EARLY THIS
EVENING IFR TO MVFR CONDITIONS ARE EXPECTED TO OCCUR.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR KSZ027>029-041-042.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DLF
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
446 AM MDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 446 AM MDT THU AUG 8 2013
FORECAST CONCERNS WILL BE THREAT OF HEAVY RAINFALL AND CHANCES OF
PRECIPITATION. SATELLITE SHOWING LITTLE CHANGE AS A COMPLEX AND
AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO NORTH AMERICA
REMAINS IN PLACE. COMPLEX AND SLOW MOVING UPPER HAS MOVED INTO
COLORADO AND NEW MEXICO. SEVERAL SHORTWAVE TROUGHS ROTATING AROUND
THIS MAIN SYSTEM. AIR MASS REMAINS MOIST THROUGH A DEEP LAYER.
PERSISTENT FRONTAL BOUNDARY REMAINS DRAPED TO OUR SOUTH AND WEST.
AT JET LEVEL...THE CANADIAN AND THE UKMET INITIALIZED BEST ON THE
JET THAT IS OVER/NEAR OUR AREA. AT MID LEVELS...SATELLITE AND UPPER
AIR ANALYSIS SHOW THAT THE ECMWF/CANADIAN FOLLOWED BY THE GFS ARE
HANDLING CURRENT SYSTEM THE BEST. SREF AND RUC WERE DOING BEST AT
THE SURFACE.
COMPLICATED AND DIFFICULT PRECIPITATION FORECAST MADE MORE DIFFICULT
BY THE FACT THAT MOST IF NOT ALL THE MODEL OUTPUT HAS CURRENT
PRECIPITATION SHIELD TOO FAR SOUTH AND IS BASICALLY IGNORING IT.
TODAY/TONIGHT...WEAK RIGHT REAR QUADRANT OF THE UPPER JET REMAINS
OVER THE AREA FOR MOST OF THE DAY. MODELS ARE IN A LITTLE MORE
DISAGREEMENT ON HOW FAST TO MOVE THIS SEGMENT EAST. ALTHOUGH THE
GENERAL TREND IS TO HAVE THIS SLOWER/FURTHER WEST THAN THE PREVIOUS
TWO DAYS. THE SLOWEST OF THE MODELS DO NOT TAKE THIS RIGHT REAR
QUADRANT TO THE EAST OF THE FORECAST AREA UNTIL BETWEEN 06Z AND 12Z.
BASED ON CURRENT SATELLITE...LATEST ECMWF IS CATCHING THE POSITION
AND COMPLEXITY OF THE UPPER TROUGH THE BEST. CONSIDERING THE
POSITION OF THE 700 MB LOW CIRCULATION...MODELS INDICATING WARM
ADVECTION/UPGLIDE IN ADVANCE OF IT...PLUS STRONG UPPER DIVERGENCE
INDICATED THE EASTERN PORTION OF THE AREA...BELIEVE THE CURRENT
PRECIPITATION WILL CONTINUE TO MOVE AND DEVELOP AND MAINLY AFFECT
THE EASTERN THIRD TO HALF OF THE FORECAST AREA.
THIS LOOKS TO BE THE BEST AREA FOR MODERATE TO HEAVY RAINFALL TO
CONTINUE THROUGH AT LEAST THIS AFTERNOON. GREELEY AND WALLACE
COUNTIES APPEAR TO BE ON THE EDGE THIS AREA AT THIS TIME. HOWEVER...
BOTH OF THOSE COUNTIES...ESPECIALLY WALLACE...GOT AT LEAST 2 TO 5
INCHES OF RAINFALL LAST. SO BELIEVE CHEYENNE COUNTY COLORADO DID
NOT RECEIVE A LOT OF HEAVY RAINFALL AND DO NOT EXPECT IT TODAY...
REMOVED THEM FROM THE FLASH FLOOD WATCH. KEPT THE REMAINDER IN THE
WATCH AND EXTENDED IT THROUGH THE AFTERNOON HOURS DUE TO THE SLOW
PROGRESSION OF THE SYSTEM ACROSS THE AREA.
QUESTION THEN BECOMES HOW FAR WEST TO BRING THE PRECIPITATION. THE
ECMWF IS SHOWING WRAP AROUND PRECIPITATION AND THE HRRR INDICATING
THE SAME IDEA. VERY INTERESTING OCCURRENCE FOR THIS TIME OF YEAR.
CURRENT RADAR TRENDS WOULD INDICATE THIS IS TAKING PLACE. SO KEPT
HIGHER POPS FURTHER WEST AS A RESULT. OVERALL...IF THE ECMWF IS RIGHT
AND IT IS SUPPORTED BY THE GEFS...THIS RAINFALL...EVEN AFTER THE
INTENSITY LETS UP...WILL BE SLOW TO END AND WILL PROBABLY NOT DO SO
UNTIL LATE TONIGHT. DID NOT INSERT AT THIS TIME BUT FOG WILL BE
POSSIBLE IF RAIN QUITS SOONER AND CLEARING CAN OCCUR.
LOWERED MAXES TODAY DUE TO CONTINUED PRECIPITATION AND THICK CLOUD
COVER.
FRIDAY/FRIDAY NIGHT...INTEREST PATTERN CONTINUES. THE ECMWF SHOWING
IT MORE BUT ALSO INDICATED BY THE OTHER MODELS AND GEFS OUTPUT...
MID LEVEL TROUGH REMAINS NEAR TO OVER THE AREA WITH WHAT LOOKS TO BE
A DECENT AMOUNT OF MOISTURE LEFT. ALSO A LEFT FRONT QUADRANT OF A
SOUTHERN JET BECOMES ESTABLISHED OVER THE AREA...ESPECIALLY THE
SOUTHEAST HALF...BY THE MIDDLE OF THE DAY. THIS CONTINUES TO AFFECT
THE AREA...ESPECIALLY THE SOUTHERN HALF...THROUGH THE ENTIRE NIGHT.
SO INSERTED POPS WITH THE HIGHEST IN THE SOUTHEAST PORTION. WITH
PERSISTENT CLOUD COVER AND UNFAVORABLE SURFACE WINDS...TRENDED
MAXES DOWN A LITTLE. IF ENOUGH CLEARING CAN OCCUR AND WITH THE MOIST
AIR MASS AND WET GROUND IN PLACE...WOULD NOT BE SURPRISED TO SEE FOG
DEVELOP.
SATURDAY/SATURDAY NIGHT...SOME DIFFERENCE IN THE JET STRUCTURE
THROUGH THE DAY. AS A RESULT IT LOOKS LIKE SOME OR MOST OF THE AREA
COULD GET LIFT FROM THE JET IN THE AREA. MID LEVEL RIDGE MOVES A
LITTLE EAST WITH A SHORTWAVE TROUGH APPROACHING FROM THE WEST IN THE
AFTERNOON. LEE TROUGH STRENGTHENS WITH SOUTHERLY WINDS INCREASING.
POSSIBILITY OF SOME SURFACE CONVERGENCE IN THE FAR WEST. SO PUT IN
A SLIGHT CHANCE IN THE FAR WEST.
ABOVE MENTIONED SHORTWAVE TROUGH AND INCREASING MID LEVEL WARM AIR
ADVECTION PATTERN ALONG WITH INCREASING JET LIFT COULD CAUSE SOME
ISOLATED THUNDERSTORMS OVER THE MOST OF THE AREA. SO PULLED THE
SLIGHT CHANCE FURTHER EAST DURING THE NIGHT.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 446 AM MDT THU AUG 8 2013
UPPER PATTERN THIS PERIOD WILL SLOWLY EVOLVE FROM AN ELONGATED
EAST-WEST UPPER HIGH OVER THE SOUTHERN U.S. TO A HIGH CENTERED OVER
NEW MEXICO AND A SUBSEQUENT GRADUAL BUILDING OF HEIGHTS OVER THE
CENTRAL ROCKIES. MEANWHILE...UPPER LOWS WILL REMAIN ANCHORED OFF
THE PAC NW COAST AND NEAR JAMES BAY...RESULTING IN WEAK TO MODERATE
NORTHWEST FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS. A FEW
WEAK SHORT WAVE TROUGHS WILL LIFT OUT OF THE WEST COAST TROUGH AND
RIDE OVER THE TOP OF THE ROCKIES RIDGE...PROVIDING A FEW
OPPORTUNITIES FOR PRECIP NEXT WEEK AS THEY EMERGE ONTO THE PLAINS.
CURRENT GUIDANCE SUGGESTS THE MON-TUE TIME FRAME WILL PROVIDE
SOMEWHAT BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND THIS IS
INDICATED WITH 30-40 POPS COMPARED TO 20 POPS ON REMAINING DAYS.
NORTHWEST FLOW ALOFT WILL BRING A SURFACE CANADIAN AIRMASS DOWN NEXT
WEEK SUGGESTING HIGH TEMPERATURES WILL REMAIN SEASONAL IN THE 80S.
&&
.AVIATION....FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1110 PM MDT WED AUG 7 2013
AS TEMPERATURES COOL TO SATURATION...LOW CEILINGS SHOULD BECOME
PREDOMINANT BY SUNRISE...WITH OCCASIONAL REDUCTIONS IN VISIBILITY
IN LIGHT RAIN AND/OR FOG. FLIGHT CATEGORIES WILL BE SLOW TO
IMPROVE THURSDAY WITH MOIST CONDITIONS AND LIGHT SOUTHERLY WINDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH UNTIL 11 PM MDT /MIDNIGHT CDT/ THIS EVENING
FOR KSZ027>029-041-042.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DLF
AVIATION...024
AREA FORECAST DISCUSSION
NWS JACKSON KY
1125 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1125 AM EDT THU AUG 8 2013
HEAVY RAINFALL DID NOT MATERIALIZE OVER THE FORECAST AREA THIS
MORNING...BUT STAYED TO OUR SOUTHWEST. THE MAIN PORTION OF AN MCS
REMAINED ANCHORED IN TN...WITH JUST DEBRIS/BLOW-OFF STREAMING OVER
OUR SOUTHERN COUNTIES IN KY. NOT CONFIDENT IN HEAVY RAINFALL TODAY
THROUGH FRIDAY...BUT WILL NOT DISPUTE THAT WITH THE HIGH MOISTURE
CONTENT OF THE ATMOSPHERE...RECENT HISTORY TO OUR WEST...AND WEAK TO
MODERATE LARGELY UNIDIRECTIONAL FLOW WITH HEIGHT...THAT SOME POTENTIAL
FOR TRAINING AND HEAVY RAINFALL EXISTS. WITH FFA ALREADY IN
PLACE...WILL LEAVE IT AS IS.
HAVE REDUCED POPS A BIT FOR TODAY...HOLDING ON TO LIKELY CATEGORY IN
OUR SOUTHEAST COUNTIES WHERE NUMEROUS SHOWERS WERE ONGOING LATE THIS
MORNING...BUT ONLY USING 50 PERCENT POPS ELSEWHERE.
UPDATE ISSUED AT 628 AM EDT THU AUG 8 2013
AFTER TALKING WITH NEIGHBORING OFFICES LMK AND RLX...AS WELL AS
SEEING THE LATEST HPC QPF GUIDANCE...MADE THE DECISION TO ISSUE AN
FFA FOR THE REGION THROUGH FRIDAY EVENING. SCT CONVECTION CONTINUES
TO DEVELOP ALONG THE BOUNDARY CURRENTLY PUSHING SOUTH INTO
KENTUCKY...WITH PWAT VALUES EXPECTED TO BE IN THE 2.0 AND ABOVE RANGE
FOR A 6 HOUR TIME PERIOD BOTH THIS MORNING AND FRIDAY MORNING. WITH
SOME OF THESE SHOWERS AND THUNDERSTORMS...RAIN RATES OF 2 TO 3 INCHES
AN HOUR ARE VERY POSSIBLE. LOCALIZED FLASH FLOODING WILL BE A THREAT
THEREFORE...ESPECIALLY IN AREAS THAT HAVE MULTIPLE STORMS PASS OVER
THEIR LOCATION IN THE NEXT 48 HOURS. LATEST NAM IS ALSO TARGETING
ANOTHER SWATH OF HEAVIER PRECIP MOVING INTO THE REGION SATURDAY
MORNING...AFTER THE EXPIRATION OF THE FFA. THIS IS SUBJECT TO CHANGE
WITH LATER MODEL RUNS...SO FIGURED IT WOULD BE EASIER TO EXTEND THE
FFA IN THE FUTURE IF NEEDED RATHER THAN HAVE TO CANCEL IT AND END UP
NEEDING TO REISSUE. THE LATEST SPENES PRODUCT FROM THE SATELLITE
BRANCH ALSO PINPOINTED A LARGE SECTION OF OUR SOUTHWESTERN CWA IN
THEIR AREA OF CONCERN FOR EXCESSIVE RAINFALL THIS MORNING. THIS JUST
FURTHER SOLIDIFIED THE DECISION TO GO AHEAD AND ISSUE THE FFA FOR THE
REGION.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEW POINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 750 AM EDT THU AUG 8 2013
FOR THE MOST PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS
INFLUENCED BY THE PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES
WILL DEVELOP IN THE MORNING...WITH POSSIBLE MVFR CIGS EXPECTED AT
ONSET. THE EXACT SET UP OF THESE STORMS IN RELATION TO HOW THEY
WILL AFFECT THE TAF SITES IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY
SHOWER OR THUNDERSTORM DOES IMPACT A SITE DURING THE DAY...VIS COULD
TEMPORARILY BE REDUCED BELOW MVFR. SHOWERS AND THUNDERSTORMS WILL DIE
DOWN LATER THIS EVENING WITH LOSS OF DAYTIME HEATING...THOUGH SOME
SCT CONVECTION IS STILL POSSIBLE THROUGH THE REMAINDER OF THE TAF
PERIOD. MUCH LIKE THIS PAST NIGHT...EXPECT OVERALL CONDITIONS TO
IMPROVE TO VFR WITH LOWER CONDITIONS EXPECTED IF A SHOWER OR
LINGERING THUNDERSTORM PASSES OVER A TAF SITE. AS FAR AS FOG...SOME
TEMPORARY BR IS BEING REPORTED AT KJKL IN CONJUNCTION WITH THE
EARLIER RAIN INTERACTING WITH THE WARM HUMID CONDITIONS. LIKEWISE...
FOR TONIGHT WITH EXTENSIVE CLOUD COVER EXPECTED ACROSS MUCH OF THE
REGION...ANY WIDESPREAD FOG DEVELOPMENT IS UNLIKELY...ESPECIALLY TO A
DEGREE THAT IT WILL SIGNIFICANTLY AFFECT THE TAF SITES. WINDS THROUGH
THE PERIOD WILL BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...HAL
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW/GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
750 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 628 AM EDT THU AUG 8 2013
AFTER TALKING WITH NEIGHBORING OFFICES LMK AND RLX...AS WELL AS
SEEING THE LATEST HPC QPF GUIDANCE...MADE THE DECISION TO ISSUE AN
FFA FOR THE REGION THROUGH FRIDAY EVENING. SCT CONVECTION CONTINUES
TO DEVELOP ALONG THE BOUNDARY CURRENTLY PUSHING SOUTH INTO
KENTUCKY...WITH PWAT VALUES EXPECTED TO BE IN THE 2.0 AND ABOVE RANGE
FOR A 6 HOUR TIME PERIOD BOTH THIS MORNING AND FRIDAY MORNING. WITH
SOME OF THESE SHOWERS AND THUNDERSTORMS...RAIN RATES OF 2 TO 3 INCHES
AN HOUR ARE VERY POSSIBLE. LOCALIZED FLASH FLOODING WILL BE A THREAT
THEREFORE...ESPECIALLY IN AREAS THAT HAVE MULTIPLE STORMS PASS OVER
THEIR LOCATION IN THE NEXT 48 HOURS. LATEST NAM IS ALSO TARGETING
ANOTHER SWATH OF HEAVIER PRECIP MOVING INTO THE REGION SATURDAY
MORNING...AFTER THE EXPIRATION OF THE FFA. THIS IS SUBJECT TO CHANGE
WITH LATER MODEL RUNS...SO FIGURED IT WOULD BE EASIER TO EXTEND THE
FFA IN THE FUTURE IF NEEDED RATHER THAN HAVE TO CANCEL IT AND END UP
NEEDING TO REISSUE. THE LATEST SPENES PRODUCT FROM THE SATELLITE
BRANCH ALSO PINPOINTED A LARGE SECTION OF OUR SOUTHWESTERN CWA IN
THEIR AREA OF CONCERN FOR EXCESSIVE RAINFALL THIS MORNING. THIS JUST
FURTHER SOLIDIFIED THE DECISION TO GO AHEAD AND ISSUE THE FFA FOR THE
REGION.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEWPOINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 750 AM EDT THU AUG 8 2013
FOR THE MOST PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS
INFLUENCED BY THE PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES
WILL DEVELOP IN THE MORNING...WITH POSSIBLE MVFR CIGS EXPECTED AT
ONSET. THE EXACT SET UP OF THESE STORMS IN RELATION TO HOW THEY
WILL AFFECT THE TAF SITES IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY
SHOWER OR THUNDERSTORM DOES IMPACT A SITE DURING THE DAY...VIS COULD
TEMPORARILY BE REDUCED BELOW MVFR. SHOWERS AND THUNDERSTORMS WILL DIE
DOWN LATER THIS EVENING WITH LOSS OF DAYTIME HEATING...THOUGH SOME
SCT CONVECTION IS STILL POSSIBLE THROUGH THE REMAINDER OF THE TAF
PERIOD. MUCH LIKE THIS PAST NIGHT...EXPECT OVERALL CONDITIONS TO
IMPROVE TO VFR WITH LOWER CONDITIONS EXPECTED IF A SHOWER OR
LINGERING THUNDERSTORM PASSES OVER A TAF SITE. AS FAR AS FOG...SOME
TEMPORARY BR IS BEING REPORTED AT KJKL IN CONJUNCTION WITH THE
EARLIER RAIN INTERACTING WITH THE WARM HUMID CONDITIONS. LIKEWISE...
FOR TONIGHT WITH EXTENSIVE CLOUD COVER EXPECTED ACROSS MUCH OF THE
REGION...ANY WIDESPREAD FOG DEVELOPMENT IS UNLIKELY...ESPECIALLY TO A
DEGREE THAT IT WILL SIGNIFICANTLY AFFECT THE TAF SITES. WINDS THROUGH
THE PERIOD WILL BE LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JMW
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW/GREIF
AREA FORECAST DISCUSSION
NWS JACKSON KY
628 AM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 628 AM EDT THU AUG 8 2013
AFTER TALKING WITH NEIGHBORING OFFICES LMK AND RLX...AS WELL AS
SEEING THE LATEST HPC QPF GUIDANCE...MADE THE DECISION TO ISSUE AN
FFA FOR THE REGION THROUGH FRIDAY EVENING. SCT CONVECTION CONTINUES
TO DEVELOP ALONG THE BOUNDARY CURRENTLY PUSHING SOUTH INTO
KENTUCKY...WITH PWAT VALUES EXPECTED TO BE IN THE 2.0 AND ABOVE RANGE
FOR A 6 HOUR TIME PERIOD BOTH THIS MORNING AND FRIDAY MORNING. WITH
SOME OF THESE SHOWERS AND THUNDERSTORMS...RAIN RATES OF 2 TO 3 INCHES
AN HOUR ARE VERY POSSIBLE. LOCALIZED FLASH FLOODING WILL BE A THREAT
THEREFORE...ESPECIALLY IN AREAS THAT HAVE MULTIPLE STORMS PASS OVER
THEIR LOCATION IN THE NEXT 48 HOURS. LATEST NAM IS ALSO TARGETING
ANOTHER SWATH OF HEAVIER PRECIP MOVING INTO THE REGION SATURDAY
MORNING...AFTER THE EXPIRATION OF THE FFA. THIS IS SUBJECT TO CHANGE
WITH LATER MODEL RUNS...SO FIGURED IT WOULD BE EASIER TO EXTEND THE
FFA IN THE FUTURE IF NEEDED RATHER THAN HAVE TO CANCEL IT AND END UP
NEEDING TO REISSUE. SPENES ALSO PINPOINTED A LARGE SECTION OF OUR
SOUTHWESTERN CWA IN THEIR AREA OF CONCERN FOR EXCESSIVE RAINFALL THIS
MORNING. THIS JUST FURTHER SOLIDIFIED THE DECISION TO GO AHEAD AND
ISSUE THE FFA FOR THE REGION.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEWPOINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 137 AM EDT THU AUG 8 2013
SIMILAR SITUATION TO LAST NIGHT...WITH SCT PRECIP ACROSS THE AREA AND
CLOUD HEIGHTS VARYING FROM POCKETS OF MVFR TO MID LEVEL VFR ACROSS
THE AREA. WHERE THE TAF SITES WILL CONTINUE TO FALL WITHIN THIS
PATTERN WILL BE THE MAIN CONCERN OVERNIGHT. FOR THE MOST
PART...EXPECT VFR CONDITIONS AT TAF SITES UNLESS INFLUENCED BY THE
PASSAGE OF A RAIN SHOWER. BEST CONVECTIVE CHANCES WILL DEVELOP IN THE
MORNING...WITH POSSIBLE MVFR CIGS EXPECTED WITH ONSET. THE EXACT SET
UP OF THESE STORMS IN RELATION TO HOW THEY WILL AFFECT THE TAF SITES
IS STILL SOMEWHAT UNCERTAIN. IF A HEAVY SHOWER OR THUNDERSTORM DOES
IMPACT A SITE DURING THE DAY...VIS COULD TEMPORARILY BE REDUCED BELOW
MVFR. SHOWERS AND THUNDERSTORMS WILL DIE DOWN TOMORROW EVENING WITH
LOSS OF DAYTIME HEATING...THOUGH SOME SCT CONVECTION IS STILL
POSSIBLE THROUGH THE REMAINDER OF THE TAF PERIOD. MUCH LIKE
TONIGHT...EXPECT OVERALL CONDITIONS TO IMPROVE TO VFR WITH SOME
POSSIBLE ADJUSTMENTS IF A SHOWER OR LINGERING THUNDERSTORM PASSES OVER
TAF SITE. AS FAR AS FOG OVERNIGHT...SOME TEMPORARY BR IS BEING
REPORTED AT KJKL IN CONJUNCTION WITH THE RAIN THAT JUST PASSED OVER
INTERACTING WITH THE WARM HUMID CONDITIONS. OTHERWISE...WITH CLOUD COVER
ACROSS MUCH OF THE REGION...ANY WIDESPREAD FOG DEVELOPMENT IS
UNLIKELY...ESPECIALLY TO A DEGREE THAT IT WILL AFFECT THE TAF SITES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JMW
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...JMW
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1154 AM EDT THU AUG 8 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT INTO THE AREA TODAY AND STALL ACROSS THE
HIGHER TERRAIN THROUGH FRIDAY. A COLD FRONT MOVES THROUGH ON
FRIDAY AND FRIDAY EVENING. HIGH PRESSURE BUILDS IN FOR THE END OF
THE WEEKEND AND INTO EARLY NEXT WEEK. LOW PRESSURE WILL APPROACH
FROM THE WEST IN THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...
PLENTY OF CLEARING/INSOLATION TO OUR WEST IN NY BUT LITTLE SUN
THIS FAR EAST. SOME STORMS STILL EXPECTED LATER THIS AFTERNOON AND
EVENING...ESPECIALLY OVER SOUTHERN NH AND NORTHERN MAINE WITH
SURFACE TROUGH IN THE AREA. HAVE UPDATED TEMPERATURES...DEW
POINTS...AND POPS. POPS WERE LOWERED QUITE A BIT AND ONLY
EXPECTING 20-40% COVERAGE THIS EVENING.
&&
PREVIOUS DISCUSSION...
FIRST LINE OF SHOWERS HAS NOW EXITED THE FORECAST AREA. HAVE
ADJUSTED POPS DOWN QUITE A BIT. MOST AREAS ARE STILL OVERCAST BUT
THERE ARE A FEW BREAKS SHOWING UP IN NORTHERN NH. THIS TREND
SHOULD CONTINUE AS NEXT SURFACE TROUGH ARRIVES LATER THIS AFTERNOON.
SHOULD GET ENOUGH INSOLATION FOR A FEW STORMS DEVELOPING/MOVING
OUT OF VT EARLY THIS AFTERNOON. HRRR INITIALIZES WELL AND HAVE
FOLLOWED IT FOR THIS AFTERNOON`S CONVECTION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
ATTENTION THEN TURNS TO FNT STALLING ALONG OR S OF THE SRN CWFA
BORDER. TO THE S WILL BE AN EXTREMELY MOIST AIR MASS...WITH PWAT
VALUES INCREASING TO NEAR 2 INCHES. FOR THE GYX AREA THIS
REPRESENTATION AOA +2 SD ABOVE NORMAL. HEAVY RNFL IS LIKELY WITH
ANY CONVECTION...WITH EXTREME RNFL RATES AT TIMES. IN
ADDITION...BOUNDARY WILL PROVIDE A FOCUS FOR TRAINING CELLS. ATTM
UNCERTAINTY STILL EXISTS ON LOCATION FNT STALLS...BUT AS
CONFIDENCE GROWS SOME SORT OF FLOOD/FLASH FLOOD HEADLINE MAY BE
NECESSARY FOR A PORTION OF THE AREA. MUCH OF THAT MAY ALSO DEPEND
ON WHERE HEAVY RAIN FALLS TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
A COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION FRIDAY
EVENING...SWEEPING THE HIGHER SURFACE DEW POINTS AND PRECIPITABLE
WATER VALUES OFF THE COAST. MODELS STILL HAVE SOME ISSUES WITH THE
TIMING OF THE PASSAGE OF THE FRONT. HAVE USED A BLEND BETWEEN THE
VERY PROGRESSIVE...FAST MOVING FRONTAL PASSAGE WITH THE GFS/EURO
SOLUTION...AND THE SLOWER FROPA WITH THE NAM/GGEM SOLUTION.
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON
SATURDAY. HOWEVER...STILL PLENTY OF COLD AIR AND CYCLONIC FLOW ALOFT
ALLOWING FOR A FEW DIURNALLY DRIVEN SPRINKLES OR SCATTERED
SHOWERS...MAINLY ACROSS THE HIGHER TERRAIN OF THE MOUNTAINS. THIS
AIR MASS WILL BE NOTICEABLY COOLER AND DRIER. EXPECT CHILLY NIGHTS
WITH PATCHY FOG AS THIS SYSTEM BUILDS OVERHEAD.
MODELS IN GOOD AGREEMENT ADVANCING THE AREA OF HIGH PRESSURE OVER
OUR REGION SUNDAY INTO MONDAY. BY TUESDAY...LOW PRESSURE WILL
BEGIN TO EXIT THE GREAT LAKES REGION...BRINGING MORE SCATTERED
SHOWERS TO OUR REGION DURING THE MIDWEEK PERIOD.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDS EXPECTED TO DETERIORATE INTO GENERALLY MVFR
CIGS AND VSBYS AS FNT APPROACHES TODAY. SOME LOCAL IFR IS PSBL IN
NEAR COAST STRATUS OR SHRA/TSTM. IFR CONDS COULD BECOME MORE
WIDESPREAD NEAR THE COAST AS FNT STALL TONIGHT AND FRI AND DEEPER
MOISTURE WORKS NWD.
LONG TERM...SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EARLY FRIDAY
EVENING MAY BRING MVFR TO IFR CONDITIONS. EXPECT IMPROVING
CONDITIONS BEHIND A COLD FRONT FRIDAY NIGHT WITH VFR CONDITIONS
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...SUSTAINED ONSHORE FLOW WILL DEVELOP TODAY AHEAD OF AN
APPROACHING FNT. THIS WILL GRADUALLY BUILD SEAS TO NEAR 5 FT BY
LATE THIS EVENING...DESPITE WINDS REMAINING BLO 25 KTS. USED A
BLEND OF THE NAM BASED SWAN WITH THE WNA4 IN THE FIRST PERIOD...AS
GFS IS USUALLY TOO AGGRESSIVE WITH WINDS AND SEAS IN SLY FLOW.
LONG TERM...SOUTHERLY FLOW WILL END FRIDAY EVENING. HOWEVER SEAS
STILL EXPECTED TO BE RELATIVELY HIGH IN THE 4 TO 6 FOOT RANGE.
THEREFORE....SMALL CRAFT ADVISORIES MAY STILL BE NEEDED THROUGH
MUCH OF FRIDAY NIGHT AND POSSIBLY INTO EARLY SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
942 AM EDT THU AUG 8 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT INTO THE AREA TODAY AND STALL ACROSS THE
HIGHER TERRAIN THROUGH FRIDAY. A COLD FRONT MOVES THROUGH ON
FRIDAY AND FRIDAY EVENING. HIGH PRESSURE BUILDS IN FOR THE END OF
THE WEEKEND AND INTO EARLY NEXT WEEK. LOW PRESSURE WILL APPROACH
FROM THE WEST IN THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FIRST LINE OF SHOWERS HAS NOW EXITED THE FORECAST AREA. HAVE
ADJUSTED POPS DOWN QUITE A BIT. MOST AREAS ARE STILL OVERCAST BUT
THERE ARE A FEW BREAKS SHOWING UP IN NORTHERN NH. THIS TREND
SHOULD CONTINUE AS NEXT SURFACE TROUGH ARRIVES LATER THIS AFTERNOON.
SHOULD GET ENOUGH INSOLATION FOR A FEW STORMS DEVELOPING/MOVING
OUT OF VT EARLY THIS AFTERNOON. HRRR INITIALIZES WELL AND HAVE
FOLLOWED IT FOR THIS AFTERNOON`S CONVECTION.
&&
PREVIOUS DISCUSSION...FNT WILL APPROACH THE AREA TODAY AND BRING
AT LEAST A COUPLE ROUNDS OF SHRA/TSTMS.
EARLY TODAY AN INCREASINGLY MOISTENING ATMOSPHERE WILL RESULT IN
CLOUDS SPREADING EWD AND THICKENING. ADDITIONALLY...WAA WILL
SUPPORT WIDELY SCT SHRA ACROSS THE AREA THRU SUNRISE. A LINE OF
SHRA AND TSTMS ALONG THE FNT WILL ALSO PUSH EWD INTO WRN ZONES IN
THE NEXT SEVERAL HOURS. SO IN THE NEAR TERM HAVE TRIED TO TIME
POP WITH THIS TREND...WHICH THE HRRR SEEM TO HAVE A DECENT HANDLE
ON. A BLEND OF THAT AND THE LOCAL WRF WAS USED AS THE BASE FOR THE
FIRST HALF OF THE DAY.
AS THIS EARLY CONVECTION WEAKENS AND MOVES E...EXPECT THAT A FEW
PARTIAL BREAKS IN THE OVERCAST WILL DEVELOP THIS AFTERNOON. IT IS
THESE POCKETS OF SFC HEATING THAT WILL BECOME THE FOCUS FOR THE
AFTERNOON FORECAST. LAPSE RATES ARE MARGINAL AT BEST...BUT DEW
POINTS INCREASING TO THE UPR 60S TO NEAR 70 WILL SUPPORT MODERATE
INSTABILITY FOR LOCATIONS THAT CAN GLIMPSE SOME SUNSHINE. AMPLE
MID LVL WLY FLOW WILL SUPPORT ENOUGH EFFECTIVE SHEAR FOR SOME
STORM ORGANIZATION. AT LEAST TRANSIENT SUPERCELL STRUCTURE WILL
LEAD TO STRONGER CONVECTION CONTAINING GUSTY WINDS AND SMALL HAIL.
GREATER THREAT IS PROBABLY WIND...AS DEEP...MOIST AIR MASS WILL BE
MORE SUPPORTIVE OF MELTING HAIL. PCPN LOADING IN THE COLUMN AND
STEEP LLVL LAPSE RATES WHERE SUN PEEKS OUT IS MORE THAN ENOUGH FOR
SOME GUSTY DOWNDRAFTS. THIS HAS BEEN ADDED TO THE GRIDS...MAINLY
ACROSS NH AND EXTREME WRN ME. NOT EXPECTING ANYTHING
WIDESPREAD...BUT AN ISOLD SEVERE WX REPORT IS ENTIRELY PSBL TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
ATTENTION THEN TURNS TO FNT STALLING ALONG OR S OF THE SRN CWFA
BORDER. TO THE S WILL BE AN EXTREMELY MOIST AIR MASS...WITH PWAT
VALUES INCREASING TO NEAR 2 INCHES. FOR THE GYX AREA THIS
REPRESENTATION AOA +2 SD ABOVE NORMAL. HEAVY RNFL IS LIKELY WITH
ANY CONVECTION...WITH EXTREME RNFL RATES AT TIMES. IN
ADDITION...BOUNDARY WILL PROVIDE A FOCUS FOR TRAINING CELLS. ATTM
UNCERTAINTY STILL EXISTS ON LOCATION FNT STALLS...BUT AS
CONFIDENCE GROWS SOME SORT OF FLOOD/FLASH FLOOD HEADLINE MAY BE
NECESSARY FOR A PORTION OF THE AREA. MUCH OF THAT MAY ALSO DEPEND
ON WHERE HEAVY RAIN FALLS TODAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A COLD FRONT WILL SLOWLY PUSH THROUGH THE REGION FRIDAY
EVENING...SWEEPING THE HIGHER SURFACE DEW POINTS AND PRECIPITABLE
WATER VALUES OFF THE COAST. MODELS STILL HAVE SOME ISSUES WITH THE
TIMING OF THE PASSAGE OF THE FRONT. HAVE USED A BLEND BETWEEN THE
VERY PROGRESSIVE...FAST MOVING FRONTAL PASSAGE WITH THE GFS/EURO
SOLUTION...AND THE SLOWER FROPA WITH THE NAM/GGEM SOLUTION.
SURFACE HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST ON
SATURDAY. HOWEVER...STILL PLENTY OF COLD AIR AND CYCLONIC FLOW ALOFT
ALLOWING FOR A FEW DIURNALLY DRIVEN SPRINKLES OR SCATTERED
SHOWERS...MAINLY ACROSS THE HIGHER TERRAIN OF THE MOUNTAINS. THIS
AIR MASS WILL BE NOTICEABLY COOLER AND DRIER. EXPECT CHILLY NIGHTS
WITH PATCHY FOG AS THIS SYSTEM BUILDS OVERHEAD.
MODELS IN GOOD AGREEMENT ADVANCING THE AREA OF HIGH PRESSURE OVER
OUR REGION SUNDAY INTO MONDAY. BY TUESDAY...LOW PRESSURE WILL
BEGIN TO EXIT THE GREAT LAKES REGION...BRINGING MORE SCATTERED
SHOWERS TO OUR REGION DURING THE MIDWEEK PERIOD.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
SHORT TERM...CONDS EXPECTED TO DETERIORATE INTO GENERALLY MVFR
CIGS AND VSBYS AS FNT APPROACHES TODAY. SOME LOCAL IFR IS PSBL IN
NEAR COAST STRATUS OR SHRA/TSTM. IFR CONDS COULD BECOME MORE
WIDESPREAD NEAR THE COAST AS FNT STALL TONIGHT AND FRI AND DEEPER
MOISTURE WORKS NWD.
LONG TERM...SHOWERS AND A FEW EMBEDDED THUNDERSTORMS EARLY FRIDAY
EVENING MAY BRING MVFR TO IFR CONDITIONS. EXPECT IMPROVING
CONDITIONS BEHIND A COLD FRONT FRIDAY NIGHT WITH VFR CONDITIONS
CONTINUING INTO EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM...SUSTAINED ONSHORE FLOW WILL DEVELOP TODAY AHEAD OF AN
APPROACHING FNT. THIS WILL GRADUALLY BUILD SEAS TO NEAR 5 FT BY
LATE THIS EVENING...DESPITE WINDS REMAINING BLO 25 KTS. USED A
BLEND OF THE NAM BASED SWAN WITH THE WNA4 IN THE FIRST PERIOD...AS
GFS IS USUALLY TOO AGGRESSIVE WITH WINDS AND SEAS IN SLY FLOW.
LONG TERM...SOUTHERLY FLOW WILL END FRIDAY EVENING. HOWEVER SEAS
STILL EXPECTED TO BE RELATIVELY HIGH IN THE 4 TO 6 FOOT RANGE.
THEREFORE....SMALL CRAFT ADVISORIES MAY STILL BE NEEDED THROUGH
MUCH OF FRIDAY NIGHT AND POSSIBLY INTO EARLY SATURDAY MORNING.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
725 AM EDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU AUG 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP MID LEVEL LOW OVER
NRN ONTARIO JUST E OF THE MANITOBA/ONTARIO BORDER. FOR THIS TIME OF
YEAR...THE LOW IS UNUSUALLY DEEP WITH 500MB HEIGHTS 2.5 STANDARD
DEVIATIONS BELOW THE LONG TERM AVG. THE UPPER LAKES ARE UNDER THE
SRN PORTION OF ITS RATHER EXPANSIVE CIRCULATION. IN THE WAKE OF THE
SHORTWAVES THAT PASSED ACROSS THE UPPER LAKES YESTERDAY...A DRY AIR
MASS HAS PUSHED INTO UPPER MI. COMBINED WITH CLEAR SKIES AND
LIGHT/CALM WIND...TEMPS HAVE ONCE AGAIN DIPPED AS LOW AS THE UPPER
30S IN SOME OF THE TRADITIONAL COLD SPOTS IN THE INTERIOR (DOE LAKE
AND SPINCICH LAKE IN PARTICULAR). JUST TO THE W...A SHORTWAVE THAT
WAS MUCH MORE WELL DEFINED YESTERDAY AFTN HAS WEAKENED/SHEARED E
INTO MN...AND IT IS SPREADING A BAND OF MID CLOUDS ACROSS NRN MN AND
WRN LAKE SUPERIOR. AFTER DIMINISHING...A BAND OF SHRA HAS
REDEVELOPED ACROSS NRN MN IN ASSOCIATION WITH THE SHORTWAVE. TO THE
NW OVER MANITOBA...A SHORTWAVE SPOKE IS EVIDENT ROTATING AROUND THE
DEEP MIDLEVEL LOW OVER NRN ONTARIO. BOTH OF THESE SHORTWAVES WILL
HAVE SOME IMPACT ON THE WEATHER HERE TODAY/TONIGHT.
FIRST UP...THE WEAKENING SHORTWAVE OVER MN WILL PASS ACROSS THE AREA
THIS MORNING. SEVERAL OF THE HIGH RES MODELS INCLUDING NAM AND HIGH
RES WRF-ARW/WRF-NMM HAVE DONE A NICE JOB PICKING UP ON THE LOCATION
OF SHRA TO THE W AND SUGGEST SHRA WILL TEND TO DISSIPATE AS THEY
SHIFT E INTO WRN UPPER MI THIS MORNING. WILL GENERALLY FOLLOW THIS
IDEA AND SPREAD ISOLD -SHRA INTO PORTIONS OF WRN UPPER MI THIS
MORNING. DURING THE AFTN...NEXT SHORTWAVE CURRENTLY ROTATING THRU
SRN MANITOBA SHOULD PROVIDE FORCING FOR ISOLD TO PERHAPS SCT AFTN
CONVECTION WITH LAKE BREEZES PROVIDING A LOW LEVEL FOCUS AS WELL.
WITH MLCAPES ONLY UP TO A COUPLE HUNDRED J/KG...THUNDER POTENTIAL IS
MINIMAL...BUT PROBABLY STILL WORTHY OF INCLUDING MENTION IN FCST.
ISOLD/SCT SHRA SHOULD SLOWLY SHIFT E AND SE TONIGHT AS PRONOUNCED
MID LEVEL DRYING PUSHES IN FROM THE W. THIS SHOULD ALSO LEAD TO
CLEARING OVER AT LEAST THE W HALF OR SO OF THE FCST AREA. LEANED
SOMEWHAT TOWARD THE LOWER SIDE OF AVBL GUIDANCE FOR MINS OVER THE W
WITH EXPECATION OF CLEARING AND A DRYING COLUMN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 518 AM EDT THU AUG 8 2013
OMEGA BLOCKING FROM ALASKA TO EASTERN CANADA WILL FINALLY BEGIN TO
BREAKDOWN...ALBEIT SLOWLY...BY THIS WEEKEND. BESIDE A CHANCE FOR
SHOWERS AND STORMS SUNDAY AFTERNOON INTO MONDAY NIGHT...THE LONG
TERM TREND WILL BE DRY AND SLIGHTLY COOLER THAN NORMAL.
FRIDAY THROUGH SATURDAY NIGHT...A DEEP CLOSED MID-LEVEL LOW OVER
NORTHERN ONTARIO WILL BE SENDING A SHORTWAVE TROUGH ACROSS THE CWA
THURSDAY NIGHT. THE ASSOCIATED COLD FRONT IS PROGGED TO CLEAR THE
CWA BY 12Z FRIDAY...WITH MUCH DRIER AIR USHERING IN BEHIND IT. SOME
LOW-LEVEL MOISTURE COULD LINGER ACROSS THE EAST HALF AFTER 12Z UNDER
INCREASING SUBSIDENCE BEHIND THE FRONT...SO KEPT SLIGHT CHANCE POPS
FOR A FEW HOURS BEYOND 12Z FOR THE FAR EAST.
THE MAIN TROUGH AXIS WILL THEN PUSH SOUTHEASTWARD ACROSS THE CWA
FRIDAY AFTERNOON INTO LATE FRIDAY NIGHT. WHILE MOISTURE IS LACKING
IN THE MID-LEVELS...H8 TO H7 FGEN UNDER MODEST MID-LEVEL
Q-VECTOR CONVERGENCE WILL LEAD TO INCREASED CLOUDINESS BELOW H5. THE
NAM IS THE ONLY MODEL TO INDICATE A SHOT AT ISOLATED SHOWERS ACROSS
THE NORTH CLOSER TO THE MAIN FORCING. HAVE OPTED TO KEEP ANY PRECIP
OUT OF THE FORECAST FOR NOW GIVEN VERY DRY LOW LEVELS AND THAT MOST
MODELS HAVE BEEN CONSISTENT WITH ALL PRECIP REMAINING OUT OF THE
CWA. MODEL TRENDS HAVE ALSO SHOWED A STRONGER PRESSURE
GRADIENT...ESPECIALLY NORTH....WITH THE TROUGH PASSAGE. WEAK
STABILITY SUGGESTS THAT MIXING COULD BRING GUSTY WNW OF UP TO 25 MPH
TO MUCH OF THE NORTH HALF BY THE AFTERNOON.
SFC HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WITH
MID-LEVEL SHORTWAVE RIDGING FRIDAY NIGHT THROUGH SATURDAY. GENERALLY
CLEAR SKIES AND LOW PWATS OF AROUND 0.5 INCHES WILL BE CONDUCIVE FOR
GOOD RADIATIONAL COOLING ACROSS MUCH OF THE CWA...PARTICULARLY THE
INTERIOR WEST HALF. HAVE FOLLOWED THE PREVIOUS SHIFTS TREND OF
LOWERING TEMPS. WIDESPREAD 40S ARE LIKELY FOR ALL BUT THE IMMEDIATE
GREAT LAKES SHORELINES. WEAK LOW-LEVEL MOISTURE RETURN WILL BEGIN
ACROSS THE WEST SATURDAY AFTERNOON AS THE SFC HIGH MOVES EAST. WITH
THIS MOISTURE INCREASE...AFTERNOON CUMULUS DEVELOPMENT WILL BE
COMMON. A FEW ISOLATED DIURNAL SHOWERS COULD EVEN BE POSSIBLE...BUT
ONCE AGAIN...CONFIDENCE IS TOO LOW TO INTRODUCE ANY PRECIP ATTM. LOW
TO MID-LEVEL CLOUDINESS WILL CONTINUE TO INCREASE WITH THE MOISTURE
RETURN SATURDAY NIGHT...KEEPING TEMPS SEVERAL DEGREES WARMER THAN
FRIDAY NIGHT.
SUNDAY THROUGH MONDAY...ANOTHER SHORTWAVE TROUGH ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN MID-LEVEL TROUGH WILL BE DIGGING SOUTHWARD
ACROSS FAR WESTERN ONTARIO LATE SATURDAY NIGHT. THE ECMWF HAS SLOWED
THIS TROUGH PASSAGE OVER THE LAST FEW RUNS...AND NOW LINES UP WELL
WITH THE GFS IN BRINGING THE MAIN TROUGH AXIS THROUGH MONDAY
EVENING. BOTH MODELS HAVE ALSO RECENTLY PICKED UP ON A WEAK LEAD
SHORTWAVE TROUGH FROM PHASING BETWEEN A PORTION OF THE MAIN TROUGH
AND A WEAK WAVE MOVING EASTWARD FROM WESTERN CANADA. THE TIMING OF
THIS WEAK WAVE IS A LITTLE DIFFERENT BETWEEN THE TWO MODELS...WITH
THE CONSENSUS BEING EARLY SUNDAY EVENING. INSTABILITY WILL BE QUITE
POOR NORTH OF THE WI BORDER AND SHOULD PRECLUDE ANY STRONG
THUNDERSTORM THREAT ATTM. THE TROUGH WILL CONTINUE TO SLOWLY WORK
EASTWARD ACROSS THE CWA AND BRING ISOLATED TO SCATTERED SHOWERS
THROUGH MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...BY THIS POINT...THE ECMWF AND GFS
HAVE SOME DISAGREEMENT ON THE STRENGTH OF THE SHORTWAVE...AND HOW
QUICK IT WILL DEPART. THE ECMWF IS MUCH QUICKER AND BRINGS GENERALLY
DRY CONDITIONS THROUGH WEDNESDAY. THE GFS SWINGS A STRONG SECONDARY
TROUGH ACROSS THE EASTERN CWA ON TUESDAY...BUT LIMITS SHOWERS TO
ONLY THE EAST HALF. STUCK WITH OVERALL MODEL CONSENSUS FOR
NOW...THROUGH MUCH OF THE PERIOD SHOULD REMAIN DRY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 724 AM EDT THU AUG 8 2013
VFR CONDITIONS WILL PERSIST THRU THIS FCST PERIOD AT KIWD/KCMX/KSAW
AS AIR MASS REMAINS DRY IN THE LOW-LEVELS. A COUPLE OF DISTURBANCES
WILL BRING THE POTENTIAL FOR A FEW -SHRA...FIRST OVER WRN UPPER MI
THIS MORNING AND THEN MAINLY OVER CNTRL UPPER MI THIS AFTN/EVENING.
PER RADAR TRENDS...IT APPEARS THAT IF -SHRA/SPRINKLES CURRENTLY OVER
WRN LAKE SUPERIOR HOLD TOGETHER...THEY WILL PASS BTWN KIWD/KCMX THIS
MORNING. EVEN IF PCPN REACHES EITHER TERMINAL...CONDITIONS WILL
REMAIN VFR. CONFIDENCE IN PLACEMENT/COVERAGE OF ANY AFTN -SHRA IN
CNTRL UPPER MI IS TOO LOW RIGHT NOW TO WARRANT ANYTHING MORE THAN A
MENTION OF VCSH AT KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT THU AUG 8 2013
EXPECT WINDS UNDER 20KT ACROSS LAKE SUPERIOR TODAY/TONIGHT UNDER A
GENERALLY WEAK PRES GRADIENT. HOWEVER...WINDS WILL BEGIN TO INCREASE
OVERNIGHT TONIGHT AHEAD OF THE NEXT COLD FRONT DROPPING SE. AN
INCREASING PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM
SOUTH CENTRAL CANADA AND LOW PRESSURE EXITING TO THE EAST ACROSS
EASTERN ONTARIO WILL CREATE W TO WNW WINDS OF 15 TO 25 KNOTS ACROSS
WESTERN LAKE SUPERIOR FRIDAY MORNING...AND CENTRAL AND EASTERN LAKE
SUPERIOR FRIDAY AFTERNOON. WEST WINDS UNDER 15 KNOTS WILL THEN BE THE
RULE THROUGH THE WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE UPPER
GREAT LAKES. ANOTHER TROUGH WILL CROSS LAKE SUPERIOR ON MONDAY AND
BRING NW WINDS UNDER 15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1010 AM CDT Thu Aug 8 2013
.UPDATE:
Issued at 1004 AM CDT Thu Aug 8 2013
Have updated forecast to reflect that area of showers and thunderstorms
over the Ozarks continues to moves east and slightly north. In addition,
scattered thunderstorms have developed recently along the across
Gasconade and Franklin counties. Latest runs of the HRRR and RAP
are showing that a low level moisture convergence maximum will
move east into southern Illinois later this morning. Now believe
that north edge of the rain will move north to about the Missouri
River before diminishing with greatest chances shifting eastward
from the Ozarks into southern Illinois. Will keep with the idea
that areal coverage of the rain will diminish early-mid afternoon.
Then the atmosphere will become increasing unstable by late
afternoon, particularly over southern Missouri at the same time
that low level moisture convergences increases from southern
Missouri into central Missouri between 21-00Z. HRRR reflectivity
shows that discrete storms may initially develop late this
afternoon into early this evening. A few severe thunderstorms will
be possible depending on the amount of instability that is able to
work into the area. Storms will also be possible of producing
heavy rainfall rates.
Britt
&&
.SHORT TERM: (Through Sunday)
Issued at 404 AM CDT Thu Aug 8 2013
Cold front is now over southern portions of forecast area early
this morning. Storms that had fired along it have long since
dissipated. Otherwise...storms have fired on nose of low level jet
once again, but further south over far southwestern Missouri.
Also, an MCS has developed over north central Oklahoma and it`s
associated MCV will continue to track to the east along frontal
boundary today. So will see scattered storms fire and move along
front, making some progress to the north, but remain along and
south of I-70. Because of the light surface winds and plenty of
low level moisture, some patchy dense fog has developed over far
southern and eastern portions of forecast area this morning, but
should dissipate as high and mid clouds move in later this
morning. As for high temperatures, low to mid 80s a good bet.
By tonight, models continue to develop another MCS over eastern
Kansas and slide it east, but have differing opinions on placement
of system, with NAM the furthest north. Will go with a blend of the
models and keep likely pops going for tonight for a good portion of
the forecast area, but back off main area of activity til after 06z
and continue through day on Friday before tapering off Friday night.
Will see decent qpf amounts, but placement of heaviest rains still
hard to pin down, so will not issue a Flash Flood Watch at this
time. One may be needed for late tonight through Friday,
especially for central and southern portions of forecast area. Lows
tonight will be in the mid 60s to around 70 with highs on Friday
in the upper 70s to mid 80s.
Weak surface ridge is still expected to build in for the weekend and
into early next week, so precipitation chances to shift off to the
south, though kept chance pops for southeast Missouri and far
southwestern Illinois through Sunday. Highs to remain below normal
in the low to mid 80s through the weekend.
Byrd
.LONG TERM: (Sunday Night through Wednesday)
Issued at 404 AM CDT Thu Aug 8 2013
Surface ridge to move off to the east ahead of next weather system
by Monday, so have chances of showers and thunderstorms across the
area on Monday as system moves through, tapering off Monday night.
Then dry conditions return to the region for the rest of the
forecast period with below normal temperatures.
Byrd
&&
.AVIATION: (For the 12z TAFs through 12z Friday Morning)
Issued at 642 AM CDT Thu Aug 8 2013
Areas of ifr cigs are floating around far eastern missouri early
this morning while they become more continuous into illinois. this
low cloud may impact the st louis area taf sites through 14z then
expecting generally vfr conditions with scattered cu and high
clouds to prevail through the evening. the exception to this is
central missouri and kcou where I`m still expecting vfr conditions
but some showers could move into around midday and last for
several hours. for tonight mvfr cigs should redevelop across the
area late tonight with showers and maybe a few thunderstorms
spreading from west to east.
Specifics for KSTL:
Areas of ifr cigs are floating around far eastern missouri early
this morning and they could impact the terminal through 14z.
thereafter expecting generally vfr conditions with scattered cu
and high clouds to prevail through the evening. mvfr cigs should
redevelop across the area late tonight with showers and maybe a
few thunderstorms spreading in from the west near daybreak friday.
Glass
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
647 AM CDT Thu Aug 8 2013
.SHORT TERM...(Today through Friday)
Issued at 322 AM CDT THU AUG 8 2013
Another night of conceptual forecasting as none of the 00Z solutions
have initialized the anticipated MCS riding along the KS/OK border,
and continue to poorly handle the subtle but key features emanating
out of the western trough each afternoon. The HRRR continues to
perform exceptionally well (albeit slow on timing), but its short-
term guidance only goes so far. In any case, 07Z surface analysis
depicts a strongly convergent frontal zone across nrn OK/AR with the
greatest lift once again focused about 50 miles north of this
boundary. A secondary elevated boundary, roughly juxtaposed with the
southern extent of dry surface air, extends NE from Wichita to
Clinton to Jefferson City. Developing MCV along over SW KS will
likely begin to make the turn ENE along this northern boundary.
With that said, dry northeasterly flow should keep most of the CWA
quiet through daybreak. Much like the past several nights, a sub-
synoptic occlusion should occur as the eastward advancing MCS
overtakes the W-E stationary front. This would place the southwestern
zones under the best chances for thunder by 12Z, with a rapid
transition to a stratiform rain/embedded thunder event as an
enlarging precipitation shield pushes into the dry air over east
central KS/west central MO. A well-defined MCV should lift slowly
across the southern CWA during the day, with QPF diminishing.
The MCV passage will mark the return of deeper warm/air moisture
advection that will place us back in a preferred zone for deep moist
convection tonight and Friday. As for highs today, generally went
around 80 across the board. Despite better chances for sunshine over
the NE CWA (at least early), CAA should yield similar readings as
points further south. Convective debris/showers should limit
insolation over the srn CWA through the morning, but expect some PM
sun to boost them back up.
For tonight, the large scale mid-level trough will begin to
finally eject out of the central Rockies, establishing a surface low
across OK. Deepening southwesterly flow aloft will lift the surface
warm front back to near I-44. This will place the southern CWA in a
precarious region of strong deep layer ascent/convergence amidst
increasing moisture advection. Based only on persistence from the
past 4-5 days, greatest QPF should fall in the 06-15Z time frame
Friday. Given the frontogenetic forcing, upper support and boundary-
relative shear profiles, have significantly bumped POPs and QPF from
06Z-18Z Friday. A flash flood watch will likely be required south of
the MO river given antecedent rainfall and prospects for very heavy
rainfall tonight/Friday morning.
Highs Friday honestly a hedge toward some afternoon clearing, but
could conceivably end up in the low-mid 70s if this doesn`t occur.
Friday Night remains the biggest question mark given the large model
spread in timing of the upper trough passage. Areas along/ahead of
this mid level wind shift certainly remain under the gun for
additional precipitation and have retained moderate POPs across all
but far NW MO for that reason.
.LONG TERM...(Saturday through Wednesday)
Issued at 322 AM CDT THU AUG 8 2013
The upcoming weekend should remain dry as the region will fall under
the influence of high pressure moving southeast through the Great
Lakes. With little change in the synoptic pattern and a continuance
of progressive zonal to northwesterly flow heading into into next
week, it appears there will only be a short break to the rainfall in
the region. By Monday, upper troughing will temporarily deepen over
Manitoba and Ontario, pushing a weak shortwave into the Central
Plains. Increasing warm advection ahead of this wave will induce
showers and thunderstorms over a large area of the central CONUS
Monday into Monday night. Have increased PoPs from late Sunday
night into Tuesday morning.
Latest guidance suggests a cold front will sweep southward through
the region by Tuesday morning, with high pressure once again moving
into the western Great Lakes providing dry conditions to the local
area.
As far as temperatures are concerned, warm advection and
southwesterly surface flow on Sunday will push temperatures back
towards seasonal normals. However, past the frontal passage on
Tuesday, temperatures will likely remain below normal into the
middle of next week.
&&
.AVIATION...(For the 12Z TAFS through 12Z Friday Morning)
Issued at 644 AM CDT THU AUG 8 2013
Mesoscale convective complex continues to move ENE across southern KS
early this morning. As cloud tops have begun to warm, sharp linear
convection has now broadened into an expanding area of stratiform
rain with embedded thunder. This precipitation will be moving into an
area of drier air, so uncertainty remains as to how far northeast
lightning will persist as the system approaches. Since conditions
will otherwise be VFR, this is really the only aspect of this MCC
that is impactful to the terminals this morning. For now went with a
tempo group for thunder across the KC terminals from 14-16Z based on
linear extrapolation.
Otherwise, as the system decays, winds should remain east-northeast
to northeast at 6-8 knots, with speeds slowly increasing tonight
ahead of the next disturbance. Conditions appear favorable,
especially south of Kansas City, for an organized thunderstorm
complex once again after midnight. Outlook period of the TAF reflects
a somewhat higher confidence for rain/embedded thunder and perhaps
some lower ceilings after midnight.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH from late tonight through Friday morning FOR
KSZ057-060-105.
MO...FLASH FLOOD WATCH from late tonight through Friday morning FOR
MOZ037>040-043>046-053-054.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Bookbinder
AREA FORECAST DISCUSSION
NWS GLASGOW MT
905 AM MDT THU AUG 8 2013
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
FAIRLY QUIET AND RELATIVELY STABLE ATMOSPHERE OVER THE REGION THIS
MORNING. DOESN/T LOOK LIKE SHOWER/THUNDERSTORM ACTIVITY THIS MORNING
WILL BE GENERATED SO REMOVED THEM...BUT DID EXPAND A BIT ACROSS THE
NORTHERN ZONES FOR THE AFTERNOON. WILL AGAIN LEAN ON THE HRRR AND
RAP (RUC) MODELS AS THEY HAVE DONE BETTER AS OF LATE. TFJ
PREVIOUS DISCUSSION...
NORTHWEST FLOW ALOFT WILL CONTINUE TODAY WITH DEEP UPPER LOW OVER
WESTERN ONTARIO AND UPPER RIDGE OVER IDAHO. SHORTWAVE TROUGH OVER
SOUTHERN ALBERTA IS BRING SOME SHOWERS AND THUNDERSTORMS TO THAT
AREA AND TO A LESSER DEGREE NORTH CENTRAL MONTANA. THE SHOWERS
HAVE BEEN DISSIPATING WHEN THEY GET TO THE HAVRE AREA OVERNIGHT.
HOWEVER... WITH THE WAVE MOVING TO THE EAST... A FEW OF THESE
SHOWERS/T-STORMS COULD MAKE INTO THE NORTHERN PARTS OF THE
FORECAST AREA THIS MORNING. WILL MENTION ISOLATED SHOWERS AND
THUNDERSTORMS. SURFACE HIGH BUILDS INTO THE AREA FROM THE NORTH
THIS AFTERNOON WITH DRY WEATHER.
THE UPPER LOW MOVES TO THE EAST TONIGHT AND FRIDAY AND UPPER RIDGE
BUILDS INTO MONTANA. WITH AN UPPER TROUGH/CUT OFF LOW OVER
CALIFORNIA...SOUTHERLY FLOW ALOFT TO THE SOUTH OF MONTANA WILL
ALLOW MONSOONAL MOISTURE TO ADVECT NORTH INTO THE STATE. THIS
MOISTURE WILL MAKE INTO THE SOUTHERN ZONES FRIDAY AFTERNOON AND
SPREAD INTO THE ENTIRE FORECAST AREA FRIDAY NIGHT. THE SHOWERS AND
THUNDERSTORMS WILL BE SPOTTY SO WILL MENTION A CHANCE OR SLIGHT
CHANCE.
THE RIDGE CONTINUES TO BUILD INTO MONTANA ON SATURDAY WITH
SOMEWHAT WARMER TEMPERATURES. UNSTABLE AIRMASS WILL COMBINE WITH
WEAK FRONTAL BOUNDARY AND LINGERING MONSOONAL MOISTURE FOR A
SLIGHT CHANCE OF THUNDERSTORMS. FORRESTER
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
SYNOPTIC SET UP...A LARGE BROAD COOL CORE TROUGH EXISTS OVER THE
HUDSON BAY AND THE CANADIAN SHIELD AND PRAIRIES. A LARGE HIGH
PRESSURE HEAT DOME RESIDES OVER THE SOUTHERN AND CENTRAL PLAINS...
THE DESERT SOUTHWEST... AND INTERMOUNTAIN WEST. A RIDGE JUTS OUT OF
THIS DOME THROUGH NORTHERN IDAHO INTO BRITISH COLUMBIA. NORTHEAST
MONTANA LIES BETWEEN THESE TWO FEATURES IN ZONAL TO NORTHWEST
FLOW. TO THE WEST A TROUGH IS STEPPING ON SHORE OF NORTHERN
CALIFORNIA AND IS PUMPING SHORTWAVES INTO THE FLOW TOWARD MONTANA
AND MONSOONAL MOISTURE INTO THE DESERT SOUTHWEST AND INTERMOUNTAIN
WEST WHICH WILL CLIP SOUTHERN MONTANA.
SATURDAY NIGHT THROUGH MONDAY...FLOW ALOFT WILL BECOME NORTHWEST
WHILE THE RIDGE TO THE EAST SLOWLY ACCUMULATES MORE MOISTURE AND
MIGRATES EASTWARD INTO CENTRAL MONTANA. SLIGHT CHANCE TO CHANCE
POPS FOR AFTERNOON THUNDER COULD INITIATED ALONG A SURFACE BOUNDARY
ORIENTED NORTHWEST TO SOUTHEAST ACROSS CENTRAL AND EASTERN
MONTANA AND THEN FURTHER CONTINUED OVERNIGHT AS AIR-MASS
THUNDERSTORM DYNAMICS FED BY MONSOONAL MOISTURE TAKE OVER.
TEMPERATURES SHOULD ALSO BE TICKING UP SLOWLY. THE ONLY QUESTION
IS WHERE IS THE SURFACE BOUNDARY DRIFTING AT ANY PARTICULAR TIME.
MONDAY NIGHT TO WEDNESDAY... THE TROUGH TO THE WEST WILL MOVE
NORTH UP THE COAST OF THE PACIFIC NORTHWEST AND BRITISH COLUMBIA
AND ALLOW THE MAIN RIDGE AXIS TO MOVE EAST ACROSS MONTANA. THE TOP
OF THE RIDGE WILL BE BLUNTED AROUND THE INTERNATIONAL BORDER AND
ALLOW A FEW SHORTWAVES TO PASS BY. THIS WILL CONTINUE THE CHANCES
FOR RAIN SHOWERS EACH AFTERNOON AND OVERNIGHT PERIOD BUT FROM A
SLIGHTLY DIFFERENT LIFT MECHANISM AS THE OLD SURFACE BOUNDARY
MOVES OFF TO THE EAST AND A LEE SURFACE TROUGH TAKES OVER THE ROLE
OF AFTERNOON INITIATION.
WEDNESDAY NIGHT ONWARD... SOME DISCREPANCIES BETWEEN THE MODELS
BEGIN TO PRESENT THEMSELVES HERE AND THEREFORE DECREASE
CONFIDENCE. MAIN ISSUE IS WITH THE RIDGE BROADENING OVER THE
CANADIAN ROCKIES AND PLAINS. THIS IS A COMMON WARMING SUMMER
OCCURRENCE. HOWEVER... THIS YEAR HAS BEEN LESS THAN COMMON WITH FAR
COOLER CONDITIONS. EC AND GEM HAVE TYPICALLY CAUGHT ONTO THIS
WHERE THE GFS HAS FAILED OVER THE LAST MONTH. YET AGAIN... WE GET
A GFS THAT IS GUNG HO ON A VERY SOLID WARMING RIDGE WHILE THE EC
ENSEMBLES ALONG WITH THE UKMET... GEM... AND NOGAPS MEMBERS
LITERALLY POKE HOLES IN THE RIDGE TO THE NORTH WITH EMBEDDED
TROUGHS AND COLD CLOSED LOWS. AT THIS TIME FAR MORE LIKELY TO
BELIEVE THE OTHER MODELS AND PREDICT SOME WEAK COOLER AIR DROPPING
BACK DOWN THAN A DRAMATIC WARM UP... OR AT LEAST KEEPING
TEMPERATURES TRENDING STABLE THIS FAR OUT.
GAH
&&
.AVIATION...
VFR CEILINGS AND VISIBILITIES ARE ANTICIPATED AT THE TERMINALS
THROUGH THE TAF PERIOD. EAST TO NORTHEAST WINDS ARE EXPECTED TO
RANGE AROUND 10 KTS THROUGH THE PERIOD AS WELL. MALIAWCO
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
528 AM MDT THU AUG 8 2013
.AVIATION...
12Z TAF CYCLE
SOME PATCHES OF LOW STRATUS CLOUDS AND FOG HAVE DEVELOPED OVER
SELECT PARTS OF NORTHERN NEW MEXICO...MAINLY WHERE HEAVIER RAIN
FELL YESTERDAY AND BEST LOW LAYER MOISTURE IS. GREATEST POTENTIAL
FOR MVFR/IFR CONDITIONS WILL BE IN THE NORTHEASTERN HIGHLANDS TO
NORTHEASTERN PLAINS...NEAR KLVS...KAXX...KRTN... KCAO...AND KTCC.
ANY LOW CLOUDS WILL BURN OFF BY 08/1600UTC. SHOWERS AND STORMS
WILL THEN FAVOR NORTH CENTRAL TO NORTHEASTERN SECTIONS OF NEW
MEXICO THIS AFTERNOON AND EVENING WITH MINIMAL COVERAGE
ELSEWHERE. BREEZES WILL REMAIN LIGHT TO MODERATE OUTSIDE OF
THUNDERSTORM OUTFLOWS...AND ANY STORM DOWNPOURS WILL BE CAPABLE OF
REDUCING VISIBILITIES/CEILINGS BRIEFLY.
52
&&
.PREV DISCUSSION...330 AM MDT THU AUG 8 2013...
SURFACE BOUNDARY ATTM IN APPROXIMATELY THE SAME LOCATION AS ONE 24
HOURS. STILL CONSIDERABLE MOISTURE LINGERING OVER THE STATE WITH
SIGNIFICANTLY DRIER DEWPOINTS AS WELL AS A MUCH DRIER AIR MASS
OVERALL ACROSS CENTRAL/WRN AZ. SOMEWHAT MORE ORGANIZED CLOUD COVER
ROTG SE OVER THE FOUR CORNERS REGION...AND RUC13 CONTINUES TO
ANALYZE A WEAK CLOSED CIRCULATION AT H5 OVER NW NM/SW CO THROUGH
EARLY THIS AFTERNOON. AS THE DAY PROGRESSES...A SURFACE BOUNDARY IS
FORECAST TO BECOME MORE DEFINED OVER NE NM. THEREFORE HAVE TRENDED
TOWARDS THE HIGHER GUIDANCE POPS TODAY FOR THE NORTHEAST THIRD TO
HALF OF THE FORECAST AREA. LATEST SPC OUTLOOK HAS SLIGHT RISK FOR
SVR STORMS IN AN AREA SIMILAR TO WHAT WAS PREDICTED 24 HOURS AGO.
HAVE NOT HIGHLIGHTED THAT POSSIBILITY IN THE WX GRIDS...SO LATER
SHIFTS WILL NEED TO MONITOR.
FRONT TO PLUNGE INTO THE EASTERN PLAINS TONIGHT BUT NOT MUCH
INDICATION MODEL WISE IT WILL REACH THE RGV. FRIDAY NIGHT APPEARS AS
IF THIS POSSIBILITY IS MORE LIKELY...TRENDING SHOWER AND STORM
CHANCES UPWARD AND WESTWARD. HIGHS TODAY WILL BE A FEW DEGREES
BELOW AVERAGE MAINLY NORTH OF INTERSTATE 40...AND MAINLY OVER THE
NORTHEAST QUARTER FRIDAY. WITH POTENTIAL FORECAST FOR A MONSOON
BURST...HIGHS SATURDAY ACROSS THE NORTHWEST HALF WILL BE SEVERAL
DEGREES BELOW AVERAGE.
ANOTHER TRANSITION FORECAST IN THE WEATHER PATTERN FOR NEXT
WEEK...WITH A TREND TOWARDS WARMER AND DRIER. THE UPPER HIGH CENTER
DRIFTS BACK OVER NEW MEXICO...AND FAR ENOUGH WESTWARD TO PUT THE
NORTHEAST UNDER NORTHWEST FLOW AS LEAST FOR A DAY OR TWO.
.FIRE WEATHER...
BACK DOOR COLD FRONT HAS MOVED INTO THE EASTERN PLAINS WITH A
REINFORCEMENT OF THIS BOUNDARY EXPECTED FRIDAY NIGHT. CURRENTLY THE
REMNANTS OF THE UPPER LOW FROM AZ CONTINUE TO BECOME LESS ORGANIZED
OVER SOUTHERN CO. MOISTURE AND LINGERING ENERGY FROM THE LEFTOVER
DISTURBANCE WILL KEEP THE BEST WETTING RAIN CHANCES OVER NORTH
CENTRAL TO NORTHEASTERN NM TODAY. MODELS CONTINUE TO ADVERTISE DRIER
AIR WORKING IN FROM THE WEST TODAY...AND WATER VAPOR SATELLITE
IMAGERY SUPPORTS THIS. THEREFORE...EXPECT MINIMAL SHOWER/STORM
COVERAGE IN THE CENTRAL TO WEST CENTRAL AND NORTHWESTERN ZONES
TODAY. MINIMUM RH WILL STILL STAY AOA 20 PERCENT WITH MODERATE
SURFACE BREEZES EXHIBITING A NORTHWESTERLY COMPONENT OVER MUCH OF
THE FORECAST AREA. EXCELLENT RH RECOVERY IS EXPECTED OVER THE
NORTHEASTERN HALF OF THE FORECAST AREA TONIGHT WITH STILL GOOD
RECOVERY OF 60-80 PERCENT FARTHER WEST. CONVECTION FROM THE LATE
EVENING MAY ATTEMPT TO SHOVE AN EAST WIND BEYOND THE CENTRAL
MOUNTAIN CHAIN TONIGHT...BUT MODELS ARE NOT ENTHUSIASTIC ABOUT IT.
AT THIS TIME NO STRONG GAP/CANYON WINDS HAVE BEEN BUILT INTO THE
FORECAST THROUGH FRIDAY MORNING.
MOISTURE WILL HAVE AT LEAST WORKED TOWARD THE CENTRAL MOUNTAIN CHAIN
EARLY ON FRIDAY WITH THE AFOREMENTIONED EASTERLY WINDS...AND THIS
MOISTURE PUSH WILL CONTINUE WESTWARD INTO THE AFTERNOON. STORMS WILL
BECOME A BIT MORE WIDESPREAD ALONG THE CENTRAL MOUNTAIN CHAIN AND
TOWARD THE CONTINENTAL DIVIDE AS TEMPERATURES WARM CLOSE TO AVERAGE
IN MOST ZONES. LOWEST MINIMUM RH VALUES WILL BE IN THE SAN JUAN
BASIN FRIDAY WHERE VALUES WILL SLIP TO 20 PERCENT OR JUST SLIGHTLY
BELOW. ANY CONVECTION LATE FRIDAY EAST OF THE CENTRAL MOUNTAINS WILL
AID THE PUSH OF A REINFORCING BACK DOOR FRONT. THIS WILL CONTINUE TO
CARRY MOISTURE WESTWARD WHILE ALSO PRODUCING MODERATE TO STRONG
GAP/CANYON WINDS NEAR CENTRAL VALLEY LOCATIONS THROUGH SATURDAY
MORNING.
BETTER LOW LAYER MOISTURE TRANSPORTED FROM THE EAST WILL COUPLE WITH
A MID LEVEL MONSOON PLUME SQUEEZING INTO NM...AND THIS WILL SET THE
STAGE FOR AN ACTIVE THUNDERSTORM DAY SATURDAY. NAM MODEL IS MOST
BULLISH WITH WETTING PRECIP CHANCES AND CONSEQUENTLY BOASTS MUCH
COOLER TEMPERATURES WHICH WOULD CERTAINLY MITIGATE ANY FIRE WX
CONCERNS. PLENTY OF LEFTOVER MOISTURE TO RECYCLE ON SUNDAY WILL ALSO
YIELD A GOOD CROP OF STORMS. INTO NEXT WEEK THE UPPER HIGH IS STILL
DEPICTED AS MOVING WESTWARD OVER OR CLOSE TO NM WHILE ELONGATING
SOME ON A WEST-EAST AXIS. ANOTHER BACK DOOR FRONT IN THE NORTHEAST
COULD KEEP CONVECTIVE ACTIVITY GOING IN THE NORTHEAST LATE TUESDAY.
52
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1025 AM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1025 AM UPDATE...
AREA OF SHOWERS AND SOME THUNDER CONTINUES TO DIMINISH. WHILE MOST
OF THE AREA WILL REMAIN DRY THROUGH EARLY AFTERNOON...SHOWERS WILL
STILL BE POSSIBLE OVER THE NORTHERN TIER OF PA AND OTSEGO/DELAWARE
COUNTIES AS THESE CONTINUE TO DIMINISH. MEANWHILE AN AREA OF
CLEARING OVER THE FINGER LAKES AND CNY MAY BE ENOUGH WITH A COLD
FRONT OVER LAKE ERIE TO PROVIDE ANOTHER CHANCE THIS AFTERNOON.
BLENDED WITH THE PREVIOUS FORECAST OF HIGH CHANCE TO LOW LIKELY
LATER TODAY...BUT I DID TRY TO SHOW A NICE GAP OF MAINLY DRY
WEATHER BETWEEN NOW AND THEN. THE PREVIOUS AFD IS BELOW...
730 AM UPDATE... QUICK UPDATE TO ACCOUNT FOR LINE OF
STORMS MVG ACRS THE AREA EARLY THIS MRNG. HV TRIED TO TRACK
CATEGORICAL POPS THRU THE REGION THRU NOON TDA. TSTMS WL TAKE
AWHILE TO REACH THE I-81 CORRIDOR IN NEPA AND MAY FALL APART BFR
THEY DO AS THEY WL BE MVG INTO INCREASINGLY STABLE AIRMASS. MLCAPE
IS 500+ JOULES WHERE THEY ARE LOCATED NOW AND FURTHER TO THE EAST
IT DIMINISHES TO NR 250 J/KG PER SPC MESOANALYSIS PAGE. HWVR THINK
THAT A GOOD CHUNK OF THE AREA BTWN I-86/I-88 AND I-80 WILL SEE
SOME FORM OF PCPN THIS MORNING AND HV BUMPED POPS TO LKLY-
CATEGORICAL TO ACCNT FOR THIS. ONCE THIS LINE OF STORMS ROLLS THRU
THINK THAT MANY PLACES WL STABILIZE FOR THE REMAINDER OF THE DAY
WITH LITTLE ELSE EXPECTED. BUT THAT WL BE LOOKED AT IN FURTHER
DETAIL FOR THE NEXT UPDATE.
PREV DISCO BLO...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTERNOON WITH SPOTTY ACTIVITY IN OUR AREA. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 AM UPDATE...
VERY FEW CHANGES MADE TO INHERITED GRIDS AS GOOD AGREEMENT BETWEEN
THE GFS AND ECMWF SUPPORTS BETTER THAN AVERAGE CONFIDENCE THROUGH
THE PERIOD. UPPER PATTERN THROUGH THE TIME FRAME WILL BE DOMINATED
BY BROAD CYCLONIC FLOW ALOFT AS A BLOCKY MID-LATITUDE PATTERN
PERSISTS THANKS TO STRONG HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC
AND CANADIAN PRAIRIE PROVINCES. BOTH THE GFS AND ECMWF AGREE THAT A
SECOND UPPER LOW WILL SWING SOUTH FROM HUDSON BAY BY LATE MON/EARLY
TUESDAY WHICH WILL SEND A COLD FRONT EAST ACROSS OUR REGION AS LOW
PRESSURE TRACKS JUST OFF TO OUR NORTH. THUS EXPECT RENEWED SHWR AND
THUNDERSTORM CHANCES BY TUESDAY BEFORE DRY WX RETURNS TO CONCLUDE
THE PERIOD. BELOW NORMAL TEMPS EXPECTED WITH NO HINTS OF ANY MAJOR
WARMING SEEN FOR THE FORESEEABLE FUTURE.
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO
SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND
POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH
MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AN AREA OF SHWRS AND EMBEDDED THUNDER WILL CONTINUE MOVING EAST
THROUGH THE REGION THIS MORNING. BASED ON LATEST RADAR
TRENDS...MOST CONCENTRATED ACTIVITY WILL PREVAIL FROM THE CENTRAL
FINGER LAKES SOUTH THROUGH THE TWIN TIERS WHERE TEMPORARY MVFR AND
POTENTIALLY SOME SHORT DURATION IFR WILL BE POSSIBLE. ELSEWHERE
AT SYR AND RME...CURRENT ACTIVITY WILL LIKELY POSE LITTLE IF ANY
RESTRICTIONS AS HEAVIEST RAINS REMAIN SOUTH. A LITTLE MORE
UNCERTAIN DOWN AT AVP AS A FAIR AMOUNT OF LAND STILL NEEDS TO BE
COVERED BEFORE REACHING THE TERMINAL. FOR NOW...HAVE INSERTED A
TEMPO GROUP STARTING AT 14Z FOR POSSIBLE MVFR RESTRICTIONS.
AFTER THIS PASSES...FCST BECOMES MUCH MORE CONVOLUTED AS MODELS
CONTINUE TO SHOW SEVERAL CLUSTERS OF SHWRS/STORMS DEVELOPING AFTER
THE 18Z TIME FRAME. FOR NOW...HAVE DECIDED TO OFFER A TEMPO TSRA
MENTION EVERYWHERE BETWEEN 18-21Z UNDER THE PREMISE THAT DAYSHIFT
CAN UPDATE ONCE TRENDS BEHIND THIS MORNING/S DEPARTING WAVE BECOME
A LITTLE MORE CERTAIN. BY TONIGHT...MAIN ACTIVITY TO LIKELY
IMPACT AVP AS ADDITIONAL MOISTURE BEGINS WORKING NORTH ALONG A
COLD FRONT. ELSEWHERE...WIDESPREAD MVFR RESTRICTIONS EXPECTED TO
DEVELOP WITH OCCASIONAL IFR POSSIBLE AT BGM AND ITH AS MOISTURE
BECOMES TRAPPED BELOW DEVELOPING FRONTAL INVERSION.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...HEDEN/JAB/PVN
SHORT TERM...JAB
LONG TERM...BMW/CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
747 AM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
QUICK UPDATE TO ACCOUNT FOR LINE OF STORMS MVG ACRS THE AREA EARLY
THIS MRNG. HV TRIED TO TRACK CATEGORICAL POPS THRU THE REGION THRU
NOON TDA. TSTMS WL TAKE AWHILE TO REACH THE I-81 CORRIDOR IN NEPA
AND MAY FALL APART BFR THEY DO AS THEY WL BE MVG INTO INCREASINGLY
STABLE AIRMASS. MLCAPE IS 500+ JOULES WHERE THEY ARE LOCATED NOW
AND FURTHER TO THE EAST IT DIMINISHES TO NR 250 J/KG PER SPC
MESOANALYSIS PAGE. HWVR THINK THAT A GOOD CHUNK OF THE AREA BTWN
I-86/I-88 AND I-80 WILL SEE SOME FORM OF PCPN THIS MORNING AND HV BUMPED
POPS TO LKLY-CATEGORICAL TO ACCNT FOR THIS. ONCE THIS LINE OF
STORMS ROLLS THRU THINK THAT MANY PLACES WL STABILIZE FOR THE
REMAINDER OF THE DAY WITH LITTLE ELSE EXPECTED. BUT THAT WL BE
LOOKED AT IN FURTHER DETAIL FOR THE NEXT UPDATE.
PREV DISCO BLO...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTERNOON WITH SPOTTY ACTIVITY IN OUR AREA. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 AM UPDATE...
VERY FEW CHANGES MADE TO INHERITED GRIDS AS GOOD AGREEMENT BETWEEN
THE GFS AND ECMWF SUPPORTS BETTER THAN AVERAGE CONFIDENCE THROUGH
THE PERIOD. UPPER PATTERN THROUGH THE TIME FRAME WILL BE DOMINATED
BY BROAD CYCLONIC FLOW ALOFT AS A BLOCKY MID-LATITUDE PATTERN
PERSISTS THANKS TO STRONG HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC
AND CANADIAN PRAIRIE PROVINCES. BOTH THE GFS AND ECMWF AGREE THAT A
SECOND UPPER LOW WILL SWING SOUTH FROM HUDSON BAY BY LATE MON/EARLY
TUESDAY WHICH WILL SEND A COLD FRONT EAST ACROSS OUR REGION AS LOW
PRESSURE TRACKS JUST OFF TO OUR NORTH. THUS EXPECT RENEWED SHWR AND
THUNDERSTORM CHANCES BY TUESDAY BEFORE DRY WX RETURNS TO CONCLUDE
THE PERIOD. BELOW NORMAL TEMPS EXPECTED WITH NO HINTS OF ANY MAJOR
WARMING SEEN FOR THE FORESEEABLE FUTURE.
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO
SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND
POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH
MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AN AREA OF SHWRS AND EMBEDDED THUNDER WILL CONTINUE MOVING EAST
THROUGH THE REGION THIS MORNING. BASED ON LATEST RADAR
TRENDS...MOST CONCENTRATED ACTIVITY WILL PREVAIL FROM THE CENTRAL
FINGER LAKES SOUTH THROUGH THE TWIN TIERS WHERE TEMPORARY MVFR AND
POTENTIALLY SOME SHORT DURATION IFR WILL BE POSSIBLE. ELSEWHERE
AT SYR AND RME...CURRENT ACTIVITY WILL LIKELY POSE LITTLE IF ANY
RESTRICTIONS AS HEAVIEST RAINS REMAIN SOUTH. A LITTLE MORE
UNCERTAIN DOWN AT AVP AS A FAIR AMOUNT OF LAND STILL NEEDS TO BE
COVERED BEFORE REACHING THE TERMINAL. FOR NOW...HAVE INSERTED A
TEMPO GROUP STARTING AT 14Z FOR POSSIBLE MVFR RESTRICTIONS.
AFTER THIS PASSES...FCST BECOMES MUCH MORE CONVOLUTED AS MODELS
CONTINUE TO SHOW SEVERAL CLUSTERS OF SHWRS/STORMS DEVELOPING AFTER
THE 18Z TIME FRAME. FOR NOW...HAVE DECIDED TO OFFER A TEMPO TSRA
MENTION EVERYWHERE BETWEEN 18-21Z UNDER THE PREMISE THAT DAYSHIFT
CAN UPDATE ONCE TRENDS BEHIND THIS MORNING/S DEPARTING WAVE BECOME
A LITTLE MORE CERTAIN. BY TONIGHT...MAIN ACTIVITY TO LIKELY
IMPACT AVP AS ADDITIONAL MOISTURE BEGINS WORKING NORTH ALONG A
COLD FRONT. ELSEWHERE...WIDESPREAD MVFR RESTRICTIONS EXPECTED TO
DEVELOP WITH OCCASIONAL IFR POSSIBLE AT BGM AND ITH AS MOISTURE
BECOMES TRAPPED BELOW DEVELOPING FRONTAL INVERSION.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...JAB/PVN
SHORT TERM...JAB
LONG TERM...BMW/CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
652 AM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTERNOON WITH SPOTTY ACTIVITY IN OUR AREA. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
4 AM UPDATE...
VERY FEW CHANGES MADE TO INHERITED GRIDS AS GOOD AGREEMENT BETWEEN
THE GFS AND ECMWF SUPPORTS BETTER THAN AVERAGE CONFIDENCE THROUGH
THE PERIOD. UPPER PATTERN THROUGH THE TIME FRAME WILL BE DOMINATED
BY BROAD CYCLONIC FLOW ALOFT AS A BLOCKY MID-LATITUDE PATTERN
PERSISTS THANKS TO STRONG HIGH PRESSURE ACROSS THE NORTHERN ATLANTIC
AND CANADIAN PRAIRIE PROVINCES. BOTH THE GFS AND ECMWF AGREE THAT A
SECOND UPPER LOW WILL SWING SOUTH FROM HUDSON BAY BY LATE MON/EARLY
TUESDAY WHICH WILL SEND A COLD FRONT EAST ACROSS OUR REGION AS LOW
PRESSURE TRACKS JUST OFF TO OUR NORTH. THUS EXPECT RENEWED SHWR AND
THUNDERSTORM CHANCES BY TUESDAY BEFORE DRY WX RETURNS TO CONCLUDE
THE PERIOD. BELOW NORMAL TEMPS EXPECTED WITH NO HINTS OF ANY MAJOR
WARMING SEEN FOR THE FORESEEABLE FUTURE.
200 PM UPDATE...
AREA REMAINS UNDER A BROAD LONG WAVE UPPER LEVEL TROUGH THROUGH
THE PERIOD AND SLIGHTLY COOLER THAN NORMAL TEMPERATURES WITH HIGHS
IN LOWER TO MIDDLE 70S AND NIGHTTIME LOWS IN THE 50S.
A FRONT THAT MOVED THROUGH THE AREA EARLY SATURDAY IS FORECAST TO
STALL IN A EAST-WEST MANNER ACROSS VIRGINA SATURDAY NIGHT INTO
SUNDAY. FROM THIS POINT MODELS HAVE DIFFERENCES OF TIMING AND
POSITIONING OF WAVES MOVING EASTWARD ALONG THIS FRONT THROUGH
MIDWEEK CAUSING SOME UNCERTAINTY IN THE FORECAST.
FORECASTED CLOUDS TO SPREAD NORTH WITH A WAVE ON SUNDAY BUT JUST
PLACED A SLIGHT CHANCE THUNDERSTORMS IN THE POCONOS FOR SUNDAY
AFTERNOON. HIGH PRESSURE BUILDS ACROSS SUNDAY NIGHT BEHIND THIS
WAVE. A SHORT-WAVE MOVING AROUND THE UPR LEVEL LOW TO OUR NORTH
MAY BRING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS IN THE
AFTERNOON MONDAY.
UNCERTAINTY INCREASES TUESDAY AS GFS LINKS A SHORT-WAVE MOVING
AROUND THE UPR LOW TO THE NORTH WITH A SURFACE LOW AND WAVE MOVING
NORTHEAST ALONG THAT FRONTAL ZONE AND SPREADS CLOUDS AND
PRECIPITATION NORTHEAST ACROSS THE AREA TUESDAY. ON THE OTHER HAND
THE ECMWF DOES NOT LINK A WAVE UP FROM THE SOUTH WITH JUST AN
ISOLATED CHANCE. PUT A 30 POP IN TUESDAY AFTERNOON. SURFACE HIGH
PRESSURE BUILDS IN FOR WEDNESDAY WITH A SHORTWAVE RIDGE ALOFT.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AN AREA OF SHWRS AND EMBEDDED THUNDER WILL CONTINUE MOVING EAST
THROUGH THE REGION THIS MORNING. BASED ON LATEST RADAR
TRENDS...MOST CONCENTRATED ACTIVITY WILL PREVAIL FROM THE CENTRAL
FINGER LAKES SOUTH THROUGH THE TWIN TIERS WHERE TEMPORARY MVFR AND
POTENTIALLY SOME SHORT DURATION IFR WILL BE POSSIBLE. ELSEWHERE
AT SYR AND RME...CURRENT ACTIVITY WILL LIKELY POSE LITTLE IF ANY
RESTRICTIONS AS HEAVIEST RAINS REMAIN SOUTH. A LITTLE MORE
UNCERTAIN DOWN AT AVP AS A FAIR AMOUNT OF LAND STILL NEEDS TO BE
COVERED BEFORE REACHING THE TERMINAL. FOR NOW...HAVE INSERTED A
TEMPO GROUP STARTING AT 14Z FOR POSSIBLE MVFR RESTRICTIONS.
AFTER THIS PASSES...FCST BECOMES MUCH MORE CONVOLUTED AS MODELS
CONTINUE TO SHOW SEVERAL CLUSTERS OF SHWRS/STORMS DEVELOPING AFTER
THE 18Z TIME FRAME. FOR NOW...HAVE DECIDED TO OFFER A TEMPO TSRA
MENTION EVERYWHERE BETWEEN 18-21Z UNDER THE PREMISE THAT DAYSHIFT
CAN UPDATE ONCE TRENDS BEHIND THIS MORNING/S DEPARTING WAVE BECOME
A LITTLE MORE CERTAIN. BY TONIGHT...MAIN ACTIVITY TO LIKELY
IMPACT AVP AS ADDITIONAL MOISTURE BEGINS WORKING NORTH ALONG A
COLD FRONT. ELSEWHERE...WIDESPREAD MVFR RESTRICTIONS EXPECTED TO
DEVELOP WITH OCCASIONAL IFR POSSIBLE AT BGM AND ITH AS MOISTURE
BECOMES TRAPPED BELOW DEVELOPING FRONTAL INVERSION.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...
SHORT TERM...JAB
LONG TERM...BMW/CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
705 AM EDT THU AUG 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE
EAST OVER THE NEXT SEVERAL DAYS. WARMER AND MORE HUMID AIR WILL MOVE
INTO THE CAROLINAS ON SOUTH WINDS...ACCOMPANIED BY SCATTERED SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...LOW STRATUS DID NOT DEVELOP AT ALL INLAND
THIS MORNING...RATHER UNEXPECTED GIVEN THE VERY GOOD RADIATIONAL
COOLING CONDITIONS WE HAD. OVER THE NEXT 3 HOURS LOOK FOR SCATTERED
SHOWERS TO DEVELOP NEAR CAPE FEAR AND SPREAD NORTH ACROSS
SOUTHEASTERN NORTH CAROLINA. OTHERWISE NO SIGNIFICANT CHANGES HAVE
BEEN MADE TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
AFTER ENJOYING SEVERAL DAYS OF BELOW-NORMAL TEMPERATURES AND
HUMIDITY...THE REALITY OF AUGUST RETURNS TO THE CAROLINAS TODAY. THE
SURFACE RIDGE AXIS THAT HELD OUR SURFACE WINDS EASTERLY OVER THE
PAST SEVERAL DAYS IS GONE. BERMUDA HIGH PRESSURE WILL ESTABLISH A
SOUTH FLOW ACROSS THE AREA TODAY WITH TEMPERATURES RISING TO AROUND
90 INLAND AND UPPER 80S NEAR THE COAST.
WITH NO SUBSIDENCE INVERSIONS TO DEAL WITH TODAY AND SURFACE-BASED
CAPE BUILDING TO AROUND 1000 J/KG...LOOK FOR SCATTERED SHOWERS AND A
FEW T-STORMS TODAY AS WELL. ACTIVITY COULD GET A VERY EARLY START
ALONG THE COAST AND PARTICULARLY IN THE CAPE FEAR REGION WHERE THE
LAST SEVERAL RUNS OF THE HRRR INDICATE SHOWERS MAY DEVELOP AS EARLY
AS SUNRISE NEAR SOUTHPORT AND WILMINGTON. BY LATE MORNING SCATTERED
CONVECTION SHOULD BE LINING UP ALONG THE DEVELOPING SEABREEZE
BOUNDARY...LIFTING SLOWLY INLAND THROUGH THE AFTERNOON HOURS.
FORECAST POPS RANGE FROM 20-40 PERCENT...HIGHEST ACROSS SE NORTH
CAROLINA.
FOR TONIGHT...INLAND CONVECTIVE ACTIVITY SHOULD GRADUALLY DIMINISH
DURING THE EVENING HOURS WITH SKIES BECOMING MOSTLY CLEAR TO PARTLY
CLOUDY. SOME LOW STRATUS MAY DEVELOP VERY LATE TONIGHT INLAND AS
SATURATION OCCURS WITHIN THE BOUNDARY LAYER BUT 1000-FOOT WINDS
REMAIN A LITTLE TOO STRONG FOR FOG. LOWS WILL FALL TO 72-74 INLAND
AND 73-78 NEAR THE COAST. SOME SOUTH-FACING BEACHES COULD SEE LOW
TEMPERATURES STRUGGLE TO DROP BELOW 80 IF THE ONSHORE WIND CONTINUES
THROUGH THE NIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...MID LEVEL RIDGE WILL REMAIN ACROSS THE AREA
AS A WESTERLY PATTERN DEVELOPS AT THE MID LEVELS. HOWEVER THERE WILL
BE INTERVALS OF RICHER THETA-E AIR TRAVERSING THE ZONAL FLOW WHICH
WARRANTS AT LEAST LOW CHANCE POPS THROUGH THE PERIOD. THE NUMEROUS
CLUSTERS OF THUNDERSTORMS WE HAVE SEEN MOVING ACROSS THE TENNESSEE
VALLEY WILL NOW TAKE AIM ON THE CAROLINAS. THE PIEDMONT TROUGH WILL
BE ENHANCED WITH THE WESTERLY FLOW WHICH WILL ASSIST IN THE FORCING
AS WELL. I HAVE MAINTAINED THE CHANCE POPS...MAINLY ON A DIURNAL
BASIS THROUGH THE PERIOD. AS WE GET CLOSER TO THE WEEKEND...THERE
WILL BE TIMES WHEN LIKELY POPS WILL BE WARRANTED BUT THIS WILL BE
BETTER ADDRESSED WITH THE NEAR TERM FORECAST. TEMPERATURE TRENDS
REMAIN RELATIVELY UNCHANGED WITH THE STRONG RIDGE AND DOWNSLOPE
COMPONENT LEADING TO READINGS SLIGHTLY ABOVE CLIMATOLOGY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...MEDIUM RANGE GUIDANCE IS TRENDING TOWARD A
RATHER WET SCENARIO FOR THE EXTENDED PERIOD. ELONGATED MID LEVEL
RIDGE SHIFTS WEST AND TROUGHING DEVELOPS ACROSS THE OHIO VALLEY.
THE TROUGH REMAINS IN PLACE AS DOES THE FRONT ASSOCIATED WITH
IT...WHICH IS POSITIONED RIGHT ACROSS OUR AREA. THIS WILL PROVIDE
A GOOF FOCUSING MECHANISM FOR INTERVALS OF SHOWERS AND
THUNDERSTORMS. HAVE INCREMENTALLY INCREASED POPS TO REPRESENT THIS
TREND. TEMPERATURES FORECAST IS ALREADY SHOWING LOWER THAN USUAL
DIURNAL RANGE WITH THE MOISTURE AND NEEDED NO CHANGES WITH THE
MORNING UPDATE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 12Z...HRRR MODEL HAS BEEN PRETTY CONSISTENT IN DEVELOPING
CONVECTION BY LATE MORNING ALONG THE COAST...ASSOCIATED WITH THE
CONVERGING RESULTANT BOUNDARY. ISOLATED/SCATTERED CONVECTION WILL
TAKE A WHILE TO DEVELOP INLAND...DUE TO RELATIVELY HIGH LFC`S. MOST
OF THE CONVECTION WILL END BY 22Z OR SO. THERE IS A CHANCE OF SOME
NEAR IFR TO IFR STRATUS AFTER MIDNIGHT. WILL REEVALUATE THIS SCENARIO
WITH THE NEXT SET OF MODEL RUNS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...SEAS HAVE BUILT TO 3 FT ABOUT 6 HOURS FASTER
THAN ANTICIPATED AT THE WRIGHTSVILLE BEACH NEARSHORE BUOY. ASIDE
FROM THIS CHANGE...THE PREVIOUS FORECAST REMAINS IN GOOD SHAPE.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
THE SURFACE RIDGE AXIS THAT HAS HELD OUR WIND DIRECTIONS EASTERLY
FOR THE PAST SEVERAL DAYS HAS FINALLY BROKEN DOWN. RATHER THAN
CANADIAN HIGH PRESSURE POKING DOWN FROM THE NORTHEAST...OUR WEATHER
TODAY AND TONIGHT WILL COME UNDER THE INFLUENCE OF BERMUDA HIGH
PRESSURE FROM THE EAST. THIS MEANS WINDS WILL BECOME SOUTHERLY TODAY
AND SOUTH-SOUTHWESTERLY TONIGHT...WITH SPEEDS AVERAGING 10-12 KNOTS.
SEAS ARE CURRENTLY 2-3 FT WITH PERIODS SPLIT BETWEEN A 6 SECOND WIND
WAVE AND A WEAK 9-10 SECOND SOUTHEAST SWELL. SEAS MAY BUILD HALF A
FOOT THROUGH TONIGHT AS SOUTH WINDS FURTHER DEVELOP THE WIND WAVE
COMPONENT.
RADAR CURRENTLY SHOWS ONLY ISOLATED SHOWERS OUT BEYOND 30 MILES FROM
SHORE...BUT MODELS ARE SHOWING WE SHOULD HAVE SCATTERED SHOWERS
DEVELOPING NEARSHORE NEAR AND NORTH OF CAPE FEAR THIS MORNING.
CONVECTIVE ACTIVITY SHOULD LARGELY SHIFT INLAND THIS AFTERNOON AS
THE SEABREEZE CIRCULATION BECOMES BETTER DEVELOPED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...ELEMENTS REMAIN THE SAME FOR THE COASTAL
WATERS THROUGH THE PERIOD AS BERMUDA HIGH PRESSURE AND THE PIEDMONT
TROUGH KEEP A SOUTHWESTERLY FLOW IN PLACE. SPEEDS REMAIN STABLE IN A
RANGE OF 10-15 KNOTS...WHICH IF ANYTHING MAY BE ON THE HIGHER END
SATURDAY AFTERNOON AS THE TROUGH STRENGTHENS. THE TEPID INCREASE IN
WINDS ISN/T ENOUGH TO IMPACT SIGNIFICANT SEAS...WHICH REMAIN IN A
2-3 FOOT RANGE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...DIFFUSE FRONT WILL REMAIN JUST INLAND...AT
LEAST LOOKING AT THE LATEST WPC FORECAST AND THIS WILL KEEP A RATHER
WEAK SOUTHWESTERLY FLOW IN PLACE. SPEEDS CONTINUE TO HOVER AROUND
TEN KNOTS OR BELOW. CAN/T RULE OUT BRIEF DISRUPTIONS IN THE SYNOPTIC
FLOW WITH INTERVALS OF CONVECTION EXPECTED BUT THIS OF COURSE IS ALL
BUT IMPOSSIBLE TO FORECAST THIS FAR OUT IN TIME. SIGNIFICANT SEAS
SHOW LITTLE CHANGE AS WELL WITH 2-3 FEET AND LITTLE IN THE WAY OF A
SWELL COMPONENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TRA
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
638 AM EDT THU AUG 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE TO RIDGE INTO THE CAROLINAS FROM THE
EAST OVER THE NEXT SEVERAL DAYS. WARMER AND MORE HUMID AIR WILL MOVE
INTO THE CAROLINAS ON SOUTH WINDS...ACCOMPANIED BY SCATTERED SHOWERS
AND THUNDERSTORMS. A COLD FRONT WILL STALL NEAR OR JUST NORTH OF THE
AREA MONDAY THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...LOW STRATUS DID NOT DEVELOP AT ALL INLAND
THIS MORNING...RATHER UNEXPECTED GIVEN THE VERY GOOD RADIATIONAL
COOLING CONDITIONS WE HAD. OVER THE NEXT 3 HOURS LOOK FOR SCATTERED
SHOWERS TO DEVELOP NEAR CAPE FEAR AND SPREAD NORTH ACROSS
SOUTHEASTERN NORTH CAROLINA. OTHERWISE NO SIGNIFICANT CHANGES HAVE
BEEN MADE TO THE FORECAST. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
AFTER ENJOYING SEVERAL DAYS OF BELOW-NORMAL TEMPERATURES AND
HUMIDITY...THE REALITY OF AUGUST RETURNS TO THE CAROLINAS TODAY. THE
SURFACE RIDGE AXIS THAT HELD OUR SURFACE WINDS EASTERLY OVER THE
PAST SEVERAL DAYS IS GONE. BERMUDA HIGH PRESSURE WILL ESTABLISH A
SOUTH FLOW ACROSS THE AREA TODAY WITH TEMPERATURES RISING TO AROUND
90 INLAND AND UPPER 80S NEAR THE COAST.
WITH NO SUBSIDENCE INVERSIONS TO DEAL WITH TODAY AND SURFACE-BASED
CAPE BUILDING TO AROUND 1000 J/KG...LOOK FOR SCATTERED SHOWERS AND A
FEW T-STORMS TODAY AS WELL. ACTIVITY COULD GET A VERY EARLY START
ALONG THE COAST AND PARTICULARLY IN THE CAPE FEAR REGION WHERE THE
LAST SEVERAL RUNS OF THE HRRR INDICATE SHOWERS MAY DEVELOP AS EARLY
AS SUNRISE NEAR SOUTHPORT AND WILMINGTON. BY LATE MORNING SCATTERED
CONVECTION SHOULD BE LINING UP ALONG THE DEVELOPING SEABREEZE
BOUNDARY...LIFTING SLOWLY INLAND THROUGH THE AFTERNOON HOURS.
FORECAST POPS RANGE FROM 20-40 PERCENT...HIGHEST ACROSS SE NORTH
CAROLINA.
FOR TONIGHT...INLAND CONVECTIVE ACTIVITY SHOULD GRADUALLY DIMINISH
DURING THE EVENING HOURS WITH SKIES BECOMING MOSTLY CLEAR TO PARTLY
CLOUDY. SOME LOW STRATUS MAY DEVELOP VERY LATE TONIGHT INLAND AS
SATURATION OCCURS WITHIN THE BOUNDARY LAYER BUT 1000-FOOT WINDS
REMAIN A LITTLE TOO STRONG FOR FOG. LOWS WILL FALL TO 72-74 INLAND
AND 73-78 NEAR THE COAST. SOME SOUTH-FACING BEACHES COULD SEE LOW
TEMPERATURES STRUGGLE TO DROP BELOW 80 IF THE ONSHORE WIND CONTINUES
THROUGH THE NIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...MID LEVEL RIDGE WILL REMAIN ACROSS THE AREA
AS A WESTERLY PATTERN DEVELOPS AT THE MID LEVELS. HOWEVER THERE WILL
BE INTERVALS OF RICHER THETA-E AIR TRAVERSING THE ZONAL FLOW WHICH
WARRANTS AT LEAST LOW CHANCE POPS THROUGH THE PERIOD. THE NUMEROUS
CLUSTERS OF THUNDERSTORMS WE HAVE SEEN MOVING ACROSS THE TENNESSEE
VALLEY WILL NOW TAKE AIM ON THE CAROLINAS. THE PIEDMONT TROUGH WILL
BE ENHANCED WITH THE WESTERLY FLOW WHICH WILL ASSIST IN THE FORCING
AS WELL. I HAVE MAINTAINED THE CHANCE POPS...MAINLY ON A DIURNAL
BASIS THROUGH THE PERIOD. AS WE GET CLOSER TO THE WEEKEND...THERE
WILL BE TIMES WHEN LIKELY POPS WILL BE WARRANTED BUT THIS WILL BE
BETTER ADDRESSED WITH THE NEAR TERM FORECAST. TEMPERATURE TRENDS
REMAIN RELATIVELY UNCHANGED WITH THE STRONG RIDGE AND DOWNSLOPE
COMPONENT LEADING TO READINGS SLIGHTLY ABOVE CLIMATOLOGY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 300 AM THURSDAY...MEDIUM RANGE GUIDANCE IS TRENDING TOWARD A
RATHER WET SCENARIO FOR THE EXTENDED PERIOD. ELONGATED MID LEVEL
RIDGE SHIFTS WEST AND TROUGHING DEVELOPS ACROSS THE OHIO VALLEY.
THE TROUGH REMAINS IN PLACE AS DOES THE FRONT ASSOCIATED WITH
IT...WHICH IS POSITIONED RIGHT ACROSS OUR AREA. THIS WILL PROVIDE
A GOOF FOCUSING MECHANISM FOR INTERVALS OF SHOWERS AND
THUNDERSTORMS. HAVE INCREMENTALLY INCREASED POPS TO REPRESENT THIS
TREND. TEMPERATURES FORECAST IS ALREADY SHOWING LOWER THAN USUAL
DIURNAL RANGE WITH THE MOISTURE AND NEEDED NO CHANGES WITH THE
MORNING UPDATE.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...ISOLATED SHRA OVER THE ATLANTIC SHOULD REMAIN JUST EAST
OF THE ILM AIRPORT THROUGH DAYBREAK. ANTICIPATE DEVELOPMENT OF MVFR
CIGS ALONG THE COAST...WITH POSSIBLE IFR/LIFR INLAND DUE TO FOG &
LOW CIGS AN HOUR OR TWO BEFORE DAYBREAK. FLIGHT CATEGORY SHOULD
IMPROVE TO VFR NO LATER THAN 13-14Z. CANNOT RULE OUT ISOLATED
SHOWERS...THUS HAVE OPTED TO INTRODUCE VCSH AT ALL SITES...BEGINNING
ALONG THE COAST FIRST. SHOWERS WILL TAPER OFF IN THE EVENING HOURS.
EXTENDED OUTLOOK...ISOLATED AFTERNOON SHOWERS AND THUNDERSTORMS
POSSIBLE THURSDAY THROUGH SATURDAY...BECOMING SCATTERED SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM THURSDAY...SEAS HAVE BUILT TO 3 FT ABOUT 6 HOURS FASTER
THAN ANTICIPATED AT THE WRIGHTSVILLE BEACH NEARSHORE BUOY. ASIDE
FROM THIS CHANGE...THE PREVIOUS FORECAST REMAINS IN GOOD SHAPE.
PREVIOUS DISCUSSION FROM 300 AM FOLLOWS...
THE SURFACE RIDGE AXIS THAT HAS HELD OUR WIND DIRECTIONS EASTERLY
FOR THE PAST SEVERAL DAYS HAS FINALLY BROKEN DOWN. RATHER THAN
CANADIAN HIGH PRESSURE POKING DOWN FROM THE NORTHEAST...OUR WEATHER
TODAY AND TONIGHT WILL COME UNDER THE INFLUENCE OF BERMUDA HIGH
PRESSURE FROM THE EAST. THIS MEANS WINDS WILL BECOME SOUTHERLY TODAY
AND SOUTH-SOUTHWESTERLY TONIGHT...WITH SPEEDS AVERAGING 10-12 KNOTS.
SEAS ARE CURRENTLY 2-3 FT WITH PERIODS SPLIT BETWEEN A 6 SECOND WIND
WAVE AND A WEAK 9-10 SECOND SOUTHEAST SWELL. SEAS MAY BUILD HALF A
FOOT THROUGH TONIGHT AS SOUTH WINDS FURTHER DEVELOP THE WIND WAVE
COMPONENT.
RADAR CURRENTLY SHOWS ONLY ISOLATED SHOWERS OUT BEYOND 30 MILES FROM
SHORE...BUT MODELS ARE SHOWING WE SHOULD HAVE SCATTERED SHOWERS
DEVELOPING NEARSHORE NEAR AND NORTH OF CAPE FEAR THIS MORNING.
CONVECTIVE ACTIVITY SHOULD LARGELY SHIFT INLAND THIS AFTERNOON AS
THE SEABREEZE CIRCULATION BECOMES BETTER DEVELOPED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 AM THURSDAY...ELEMENTS REMAIN THE SAME FOR THE COASTAL
WATERS THROUGH THE PERIOD AS BERMUDA HIGH PRESSURE AND THE PIEDMONT
TROUGH KEEP A SOUTHWESTERLY FLOW IN PLACE. SPEEDS REMAIN STABLE IN A
RANGE OF 10-15 KNOTS...WHICH IF ANYTHING MAY BE ON THE HIGHER END
SATURDAY AFTERNOON AS THE TROUGH STRENGTHENS. THE TEPID INCREASE IN
WINDS ISN/T ENOUGH TO IMPACT SIGNIFICANT SEAS...WHICH REMAIN IN A
2-3 FOOT RANGE.
LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 300 AM THURSDAY...DIFFUSE FRONT WILL REMAIN JUST INLAND...AT
LEAST LOOKING AT THE LATEST WPC FORECAST AND THIS WILL KEEP A RATHER
WEAK SOUTHWESTERLY FLOW IN PLACE. SPEEDS CONTINUE TO HOVER AROUND
TEN KNOTS OR BELOW. CAN/T RULE OUT BRIEF DISRUPTIONS IN THE SYNOPTIC
FLOW WITH INTERVALS OF CONVECTION EXPECTED BUT THIS OF COURSE IS ALL
BUT IMPOSSIBLE TO FORECAST THIS FAR OUT IN TIME. SIGNIFICANT SEAS
SHOW LITTLE CHANGE AS WELL WITH 2-3 FEET AND LITTLE IN THE WAY OF A
SWELL COMPONENT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TRA
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...SGL/TRA
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
729 AM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH SATURDAY. A
WEAK COLD FRONT WILL ARRIVE FROM THE NORTH ON SUNDAY. THIS FRONT
WILL SLOWLY CROSS THE AREA THROUGH TUESDAY...BEFORE MOVING SOUTH OF
THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 700 AM EDT THURSDAY...ONLY A FEW LIGHT SHOWERS ARE CURRENTLY
OVER NE GA AND BACK ACROSS THE WRN NC PIEDMONT. POPS HAVE BEEN
TRIMMED TO MATCH THE CURRENT TRENDS. EVERYTHING ELSE LOOKS GOOD
RIGHT NOW.
PREVIOUS DISCUSSION...THE LATEST GSP-WSR88D WIND PROFILER DATA SHOW
NORTHERLY FLOW BETWEEN 9-13 KFT. WHILE AT THE TCLT TDWR THE FLOW AT
THIS LEVEL IS OUT OF THE WSW. THE TROUGH IS ALSO EVIDENT IN THE
REFLECTIVITIES AS PATCHY LIGHT SHOWERS ARE MOVING OUT OF THE NORTH
OVER THE CENTRAL PART OF THE UPSTATE...BUT THEY ARE MOVING FROM THE
SOUTH OVER TOWARD UNION AND GAFFNEY. WHILE THIS IS A WEAK FEATURE IT
MAY BE ENOUGH TO FINALLY KEEP IT DRY THROUGH SUNRISE ON THE BACK
SIDE OF THE TROUGH ACROSS THE BLUE RIDGE. A COUPLE CONVECTION
ALLOWING MODELS FIRE UP HEAVIER SHOWERS AND STORMS EAST OF THE
TROUGH AXIS PRIOR TO SUNRISE HOWEVER. I/M NOT CERTAIN THAT THIS
WON/T HAPPEN...BUT I DOUBT IT AT THIS POINT.
LATER IN THE MORNING THE NAM AND RUC DEVELOP CONVECTION BACK ACROSS
THE BLUE RIDGE AS A STRONGER MID-TROPOSPHERIC TROUGH APPROACHES.
THIS FEATURE IS CURRENTLY EVIDENT ON THE RUC...AND MODESTLY EVIDENT
ON WATER VAPOR IMAGERY...OVER MIDDLE TN AND SW KY. THE SHORT WAVE IS
EXPECTED TO TRIGGER NUMEROUS SHOWERS AND TSTMS OVER MOUNTAINS AND
FOOTHILLS TODAY. EVEN THE PIEDMONT MIGHT GET INTO THE ACT AS THE
LLVL FLOW IS A LITTLE MORE SOUTHWESTERLY TODAY. AS SEVERAL INCHES OF
RAIN HAS FALLEN OVER PARTS OF NE GA...UPSTATE SC AND THE SRN MTNS OF
NC OVER THE PAST 3 DAYS...I/VE ISSUED A FLASH FLOOD WATCH FOR THIS
AREA. I DID NOT TAKE IT ACROSS NRN MTNS...NRN FOOTHILLS OR THE WRN
NC/SC PIEDMONT AS ANTECEDENT CONDITIONS ARE DRIER. I HOPE I DON/T
REGRET THIS...BUT THE NEIGHBORING OFFICES ARE IN AGREEMENT ON THIS
APPROACH AS WELL.
OVERNIGHT THE AREA OF MID-LEVEL TROUGHING STRENGTHENS JUST A LITTLE
WITH SOUTHWESTERLY H5 WINDS INCREASING TO 25 KTS OVER THE WRN ZONES
ALONG WITH A COMMISERATE RESPONSE AND BACKING IN THE LLVL WIND
FIELD. THIS MAY SET THE STAGE FOR CONVECTION TO LAST A WAYS INTO THE
OVERNIGHT HOURS...OR EVEN REDEVELOP AT SOME POINT DURING THE THE
NIGHT. THE FLASH FLOOD WATCH WILL BE RUN THROUGH 6 AM FRIDAY TO
ACCOUNT FOR THIS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AT 230 AM EDT THURSDAY...AN UPPER RIDGE WILL EXTEND ACROSS THE
SOUTHEAST STATES ON FRIDAY...WHILE A CLOSED UPPER LOW CROSSES SOUTH
CENTRAL CANADA AND AN EASTERLY WAVE MOVES INTO THE SOUTHEAST GULF
OF MEXICO. THE RIDGE PERSISTS INTO SATURDAY...WHILE THE UPPER LOW
REACHES EASTERN CANADA...AND THE EASTERLY WAVE REACHES THE WESTERN
GULF.
AN ATLANTIC SURFACE RIDGE WILL MAINTAIN A HOLD ON THE CAROLINAS AND
GA ON FRIDAY...WHILE A RIVER OF GULF MOISTURE WILL EXTEND TO THE
SOUTHERN APPALACHIANS. ISENTROPIC UPGLIDE OVER THE RIDGE WILL BE
RATHER WEAK...AND UPSLOPE FLOW LIMITED BY THE SOUTHWESTERLY NATURE
OF THE WINDS. THE RIVER OF GULF MOISTURE BECOMES REORIENTED ON
SATURDAY AS THE EASTERLY WAVE AFFECTS THE GULF INFLOW...AND LOW
LEVEL WINDS VEER TO THE WEST...FAVORING THE TN BORDER FOR
PRECIPITATION. MEANWHILE...A SLOW MOVING COLD FRONT WILL OUT OF THE
OH RIVER VALLEY...APPROACHING OUR AREA FROM THE NORTH ON SUNDAY
NIGHT.
WITH DEEP MOISTURE REMAINING OVER OUR AREA...POPS WILL BE ABOVE
CLIMATOLOGY...AND WILL CONTINUE OVERNIGHT...DESPITE THE LACK OF WELL
DEFINED FORCING. ALTHOUGH QPF WILL BE LIMITED...ESPECIALLY AS FLOW
VEERS SATURDAY...THE LONG DURATION OF THE EVENT COULD PRODUCE RUNOFF
PROBLEMS IN AREAS THAT HAD GREATER RAINFALL EARLIER ON. A LIMITED
DIURNAL TEMPERATURE RANGE IS EXPECTED TO CONTINUE...WITH CLOUDS
KEEPING MAXIMUMS SLIGHTLY BELOW NORMAL...AND MINIMUMS SLIGHTLY ABOVE
NORMAL.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AT 230 AM EDT THURSDAY...AN UPPER TROUGH WILL AMPLIFY ALONG THE EAST
COAST FROM SUNDAY THROUGH WEDNESDAY. A COLD FRONT WILL DROP VERY
SLOWLY SOUTH INTO THE NORTHERN PORTION OF THE AREA ON SUNDAY...
CROSSING MUCH OF WESTERN NC ON MONDAY...THE INTERSTATE 85 CORRIDOR
TUESDAY...AND FINALLY MOVING SOUTH OF THE AREA ON WEDNESDAY.
ALTHOUGH THIS BOUNDARY WILL SERVE AS A FOCUSING MECHANISM FOR
PRECIPITATION...SOUTHERLY INFLOW AHEAD OF THE FRONT IS EXPECTED TO
DECREASE BASED ON A REORIENTATION OF THE SURFACE RIDGE TO THE SOUTH.
UPSLOPE WILL BE LIMITED TO THE TN BORDER AREA TO BEGIN WITH AS LOW
LEVEL WINDS WILL BE WESTERLY...AND WILL DIMINISH IN THE LEE OF THE
MOUNTAINS AS THE FRONT SETTLES SOUTH AND WINDS VEER MORE TO THE
NORTHWEST. POPS WILL REMAIN ABOVE CLIMATOLOGY...AND WITH SOME
UNCERTAINTY AS TO THE TIMING OF THE FRONT...POPS WILL BE ALLOWED TO
REMAIN INTO WEDNESDAY. TEMPERATURES WILL DECREASE AS HEIGHTS FALL
ALOFT...BUT THE DIURNAL RANGE WILL REMAIN LIMITED DUE TO CLOUDS AND
MOISTURE.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AT KCLT...MID-LEVEL CLOUDS AND LIGHT WINDS HELPED KEEP LOW STRATUS
FROM DEVELOPING THIS MORNING. AFTER SUNRISE...HOWEVER...ONCE THERE
IS A LITTLE HEATING SOME MVFR CIGS COULD DEVELOP...PROBABLY CLOSE TO
2KFT. WILL HINT THAT WAY WITH A SCT LAYER. SCT SHRA AND TSTMS ARE
EXPECTED IN THE AFTN...THOUGH CHANCES WILL CONTINUE TO BE HIGHER A
LITTLE CLOSER TO THE MOUNTAINS. STRATUS IS POSSIBLE AGAIN
TONIGHT...ESPECIALLY AS THE LOW LEVEL FLOW WILL BE A LITTLE
STRONGER. WENT WITH AN MVFR DECK TO ACCOUNT FOR THIS. CONFIDENCE
ISN/T VERY HIGH AS A LOT WILL DEPEND ON HOW MUCH PRECIPITATION FALLS
TODAY AND TONIGHT.
ELSEWHERE...HIGH CLOUDS AND LIGHT LLVL WINDS HAVE KEPT STRATUS FROM
DEVELOPING FOR THE MOST PART ACROSS MOST OF THE FOOTHILLS AND
PIEDMONT THIS MORNING. ASHEVILLE DID GO DOWN AND SHOULD GRADUALLY
LIFT OUT OF THE LIFR/VLIFR RANGE THIS MORNING. THERE IS STILL A
CHANCE THAT AN MVFR OR EVEN IFR DECK WILL DEVELOP ONCE THERE IS A
LITTLE HEATING AND MIXING AFTER SUNRISE. SCATTERED LAYERS WERE ADDED
OUTSIDE THE MOUNTAINS TO ACCOUNT FOR THIS. AN UPPER LOW WILL BRING A
GOOD CHANCE OF SHOWERS AND THUNDERSTORMS TO THE REGION THIS
AFTERNOON AND TEMPO GROUPS FOR THUNDER HAVE BEEN ADDED TO ALL THE
TAF SITES.
OUTLOOK...MOISTURE AND INSTABILITY CONTINUE THROUGH THE WEEKEND...
LEADING TO CONTINUED CHANCES FOR MAINLY DIURNAL CONVECTION. EARLY
MORNING PATCHY FOG AND LOW CLOUDS MAY OCCUR OVER AREAS OF RECENT
RAINFALL AND IN MTN VALLEYS.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT MED 70% HIGH 81% HIGH 100% HIGH 85%
KGSP MED 67% MED 76% HIGH 87% LOW 54%
KAVL MED 63% HIGH 85% MED 63% MED 76%
KHKY MED 67% MED 74% MED 62% LOW 59%
KGMU MED 68% HIGH 81% HIGH 87% MED 63%
KAND LOW 57% HIGH 81% HIGH 100% HIGH 80%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...HG/JAT
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...HG/MCAVOY
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
947 AM CDT THU AUG 8 2013
.UPDATE...REST OF TODAY
MADE A FEW ADJUSTMENTS TO WX/POPS FOR TODAY...MAINLY JUST SHAVING
OFF THE NORTH END WHERE CONDITIONS LOOK TO BE DRY NORTH OF THE
STALLED FRONTAL BOUNDARY. ANY ADDITIONAL SHOWER AND STORM
DEVELOPMENT THROUGH THE DAY LOOKS TO BE MAINLY NEAR AND SOUTH OF
HWY 212. LATEST HRRR RUN AND LAST NIGHTS 00Z NSSL WRF RUN ALSO
SUGGESTING THIS. CURRENT HIGHS APPEAR ON TRACK AT THIS POINT AND
NO CHANGES THERE. READINGS WILL TOP OUT IN THE 70S FOR MOST
LOCATIONS...STILL BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN AREA OF HIGH PRESSURE MOVING INTO THE REGION FROM THE NORTH
WILL PUSH A WEAK FRONTAL BOUNDARY DRAPED FROM WEST TO EAST ACROSS
CENTRAL SOUTH DAKOTA SOUTHWARD TODAY. MODELS GENERALLY AGREE WITH
PLACEMENT OF THIS FRONTAL BOUNDARY ACROSS SOUTHERN SOUTH DAKOTA
WHERE STORMS HAVE THE BEST POTENTIAL OF DEVELOPING LATER THIS
AFTERNOON. BECAUSE OF THE SOUTHERN PLACEMENT OF THE FRONTAL BOUNDARY
HAVE REMOVED POPS ACROSS THE NORTHERN PORTION OF THE CWA FOR THIS
AFTERNOON.
CANADIAN HIGH PRESSURE BUILDING INTO THE REGION TONIGHT WILL
PRODUCE DRY CONDITIONS THROUGH THE DAY ON FRIDAY. RETURN FLOW WILL
QUICKLY DEVELOP ON THE BACK SIDE OF THE HIGH PRESSURE ON FRIDAY
NIGHT OVER THE WESTERN DAKOTAS. A FAIRLY STRONG SHORT WAVE MOVING
ACROSS THE REGION WILL INTERACT WITH THE INCREASING LLM TO RESULT
IN EARLY MORNING CONVECTION FOR THE WESTERN CWA ON SATURDAY.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY NIGHT
DESPITE ALLBLEND`S GENEROUS SMATTERING OF POPS OVER SEVERAL OF THE
EXTENDED FORECAST PERIODS...SATURDAY NIGHT/SUNDAY STILL STANDS THE
BEST CHANCE OF NUMEROUS/WIDESPREAD COVERAGE OF SHOWERS AND
THUNDERSTORMS. INSTABILITY/SHEAR AND FORCING IS ALL THERE IN
SUPPORT OF SOME SORT OF ORGANIZED CONVECTIVE SYSTEM
EVOLVING/MOVING ACROSS THE CWA SATURDAY NIGHT INTO SUNDAY MORNING.
BEYOND THAT...AS WAS PREVIOUSLY MENTIONED...DETAILS GET A LITTLE
BIT FUZZIER AS SOLUTIONS BEGIN TO DIVERGE ON THE HANDLING OF
PLACEMENT/STRENGTH OF THE WESTERN CONUS UPPER LEVEL RIDGE /AND ANY
SHORT-WAVE IMPULSES EMBEDDED WITHIN THE FLOW/ WHICH IS THOUGHT TO
BE SHIFTING A BIT EAST TOWARD THE DAKOTAS BY MID-WEEK.
ALSO STILL LOOKS AS THOUGH TEMPERATURES MAY TRY TO
MODERATE/WARM-UP A BIT TOWARD THE MID TO LATE PART OF THIS COMING
WEEK...AT LEAST...CLOSER TO NORMAL FOR AUGUST.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
JUST A COUPLE OF WEAK SHOWERS LEFT ACROSS THE CWA THIS MORNING AS
FORCING/LIFT FOR CONVECTION IS DIMINISHING. CURRENT VFR
CONDITIONS...EXCEPT AT KATY /MVFR CIGS THERE/...ARE EXPECTED TO
CONTINUE TODAY AND TONIGHT. KATY SHOULD SEE CONDITIONS GRADUALLY
IMPROVING BY LATE THIS MORNING/EARLY AFTERNOON TO VFR. A FEW
SHOWERS AND THUNDERSTORMS COULD FIRE ALONG/SOUTH OF A SLOWLY
SAGGING FRONTAL BOUNDARY. KPIR COULD SEE A COUPLE OF THESE STORMS
NEARBY. BUT OVERALL...DRY CONDITIONS AMID GOOD VFR IS EXPECTED TO
PREVAIL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...SD
LONG TERM...DORN
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
752 AM EDT THU AUG 8 2013
.SYNOPSIS...
A COUPLE OF DISTURBANCES SHIFT ACROSS THE AREA THROUGH TONIGHT. A
FRONT MOVES INTO THE MOUNTAINS BY SATURDAY AND SLOWLY SHIFTS TO
THE SOUTH OF US AFTER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 720 AM EDT THURSDAY...
POCKETS OF SHOWERS/ISOLATED THUNDER MOVING ACROSS SE WV AT THE
MOMENT WILL AFFECT THE ALLGHENY HIGHLANDS SOON...WITH ISOLATED
SHOWERS PUSHING ACROSS THE TRIAD OF NC. FURTHER WEST A LINE OF
SHOWERS AND STORMS EXTENDS FROM LONDON KY WSW TO NASHVILLE TN. THE
LATEST HRRR APPEARS TO BE PICKING THIS UP PRETTY WELL BUT LINGERS
IT GOING INTO THIS MORNING WITH ONLY SCATTERED SHOWERS AFFECTING
THE WESTERN CWA. THE 00Z ECM MODEL WAS STILL DOING A GOOD ENOUGH
JOB BRINGING EMBEDDED IMPULSE OVER WV THIS MORNING INTO THE
SHENANDOAH VALLEY THIS AFTERNOON...WHILE THE KY WAVE MOVING INTO
FAR SW VA INTO NE TN. MADE SOME MINOR ADJUSTMENTS TO POPS BUT
OVERALL CONFIDENT IN HIGH CHANCE TO LIKELYS WEST TO LOWER CHANCES
OUT EAST. IF THERE IS ANY SUN...THE THUNDERSTORM CHANCES WILL
INCREASE...BUT OVERALL LOOKS LIKE ANOTHER MOSTLY CLOUDY TO OVC
DAY IN THE GRAND SCHEME OF THINGS.
PREVIOUS VALID DISCUSSION...
WITH PWATS AROUND 2.0 THE STORMS WILL BE EFFICIENT HEAVY RAIN
PRODUCERS...BUT GIVEN LACK OF WIDESPREAD RAINFALL LATELY A FLASH
FLOOD WATCH IS NOT WARRANTED. HOWEVER...SOME PLACES LIKE SUMMERS
COUNTY WV WHICH SAW SOME HEAVY RAIN WEDNESDAY IS MORE LIKELY TO BE
IMPACTED IF HEAVY RAIN MOVES SLOWLY OVER THEM TODAY. WILL HOLD OFF
AND SEE HOW THE CONVECTION TRANSPIRES TODAY BEFORE ISSUING A
WATCH.
THE ONE MAIN VORT MOVES EAST OF THE CWA BY EVENING SO EXPECT SOME
WEAKENING/DIMINISHING TREND IN THE POPS OUT EAST. THE FLOW ALOFT AND
MODEL VORTICITY FIELDS OF THE ECMWF CONTINUE TO SHOW EMBEDDED WAVES
MOVING FROM KENTUCKY INTO VIRGINIA/WEST VIRGINIA TONIGHT...AND
POSSIBLY INTO NC. LIKE THE ECMWF IDEA OF MAINTAIN HIGHER POPS ACROSS
SE WV INTO FAR SW VA...WITH LESS IN THE SOUTHEAST.
FOR TEMPS TODAY AND TONIGHT KEPT CLOSE TO WEDNESDAYS HIGHS WITH
MID 70S NC MOUNTAINS TO NEAR 80S BLF-BCB AND LOWER TO MID 80S
EAST. TONIGHT...SAME AIRMASS SO LOW SHOULD BE IN THE MID TO UPPER
60S WEST TO LOWER 70S EAST.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 400 AM EDT THURSDAY...
LOOKING AT AN INCREASED THREAT OF LOCALLY HEAVY RAIN AND POSSIBLY
FLASH FLOODING ON FRIDAY AS A STRONG SHORTWAVE TROUGH PASSES EAST
ACROSS THE GREAT LAKES DURING THE AFTERNOON AND EVENING. THE
COMBINATION OF DEEP ATMOSPHERIC MOISTURE BUILDING ALONG THE CENTRAL
APPALACHIAN CHAIN AHEAD OF THE TROUGH...MODEST INSTABILITY AND
RELATIVELY LIGHT WINDS ALOFT WILL RESULT IN SCATTERED SLOW MOVING
STORMS WITH HIGH RAINFALL RATES. THE NEED FOR A FLASH FLOOD WATCH
APPEARS LIKELY FOR SOME AREAS WEST OF THE BLUE RIDGE FOR FRIDAY...
BUT WHICH COUNTIES TO INCLUDE IN A WATCH REMAINS UNCLEAR. WOULD LIKE
TO SEE HOW RAINFALL DEVELOPS THURSDAY AFTERNOON AND EVENING BEFORE
FINALIZING ANY DETAILS OF A POTENTIAL WATCH. IN ANY EVENT...RAINFALL
WILL DIMINISH IN INTENSITY DURING LATE EVENING AS INSTABILITY
DECREASES AND WINDS SHIFT MORE WESTERLY...RESULTING IN MORE OF A
DOWNSLOPE WINDFLOW.
THE SHORTWAVE TROUGH WILL PASS RAPIDLY ACROSS EASTERN CANADA
SATURDAY MORNING...GIVING A SOUTHWARD PUSH TO A STATIONARY FRONT
NEAR THE OHIO RIVER VALLEY. THE FRONT WILL ADVANCE TO AROUND THE
INTERSTATE 81 CORRIDOR BY SATURDAY EVENING...AND INTO THE CAROLINAS
BY SUNDAY EVENING. SIGNIFICANTLY DRIER AIR WILL LAG BEHIND THE COLD
FRONT HOWEVER...AND WILL EXPECT REDEVELOPMENT OF SHOWERS AND
THUNDERSTORMS FOR SATURDAY AND SUNDAY AFTERNOON/EVENING...MORE
SPOTTY IN NATURE...WITH COVERAGE CONCENTRATED MORE ACROSS THE
MOUNTAINS...ESPECIALLY IN OUR NORTHWEST FLOW UPSLOPE AREAS. BY LATE
SUNDAY NIGHT...DRIER AIR WILL WORK ITS WAY INTO THE MOUNTAINS...
LOWERING DEWPOINTS INTO THE UPPER 50S AND LOW 60S.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 400 PM EDT WEDNESDAY...
WITH THE UPPER RIDGE CONSOLIDATING AND MOVING TO THE FOUR CORNERS
REGION...TROUGHING WILL DEEPEN AND STRENGTHEN ACROSS THE EAST AND
MIDDLE ATLANTIC. WITH THE COOLER TEMPS AND LESS MOISTURE...SHOWERS
AND STORMS WILL BECOME LESS LIKELY AND SUPPRESSED SOUTH AS THE WEEK
WEARS ON. HOWEVER...CAN`T TOTALLY RULE OUT A FEW POP UP SHOWERS
REGIONWIDE WITH SUCH CHILLY TEMPS ALOFT FOR THIS TIME OF YEAR.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 740 AM EDT THURSDAY...
GOING TO SEE SKIES STAYING BKN-OVC TODAY WITH MOSTLY VFR TAKING
PLACE. OVERALL LOOKING AT RAIN SHOWERS AND STORMS MOVING INTO THE
WV MTNS LATER THIS MORNING THEN INCREASING INTO THE BCB/ROA AREA
BY MIDDAY. HAVE ADDED PREDOMINANT SHOWERS AT THESE SITES WITH
CONFIDENCE HIGH THAT BLF/LWB WILL GET MVFR VSBYS WITH MODERATE
SHOWERS AND ISOLATED THUNDER DURING THE AFTERNOON. LOOKS LIKE
DANVILLE WILL BE THE ONLY SITE THAT HAS A LOWER THREAT SO KEPT
EVEN VCTS OUT THERE.
THE SHOWERS WILL BE LINGERING AS ANOTHER WAVE MOVES INTO THE
MOUNTAINS LATER TONIGHT. WILL BE ENOUGH CLOUD COVER FOR MVFR TO
POTENTIAL IFR CIGS AT ALL SITES TONIGHT WITH POTENTIAL FOG IF
LOWER CLOUDS CLEAR OUT SOME.
BY FRIDAY-MONDAY A FRONTAL BOUNDARY WILL BE IN THE VICINITY TO
SEE MORE COVERAGE OF SHOWERS/STORMS AREA WIDE. THIS WILL KEEP
TERMINALS DEALING WITH DELAYS DUE TO STORMS...BUT OVER HALF THE
TIME...IT SHOULD BE VFR. DRIER AIR PUSHES INTO NORTH ON MONDAY
WITH SCATTERED CONVECTION STILL POSSIBLE ESPECIALLY IN THE SOUTH.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...WP
NEAR TERM...WP
SHORT TERM...NF
LONG TERM...KM
AVIATION...DS/WP
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1032 AM CDT THU AUG 8 2013
.UPDATE...
BROKEN CLOUD DECK OVER THE SOUTHWEST AREA AND BROKEN CLOUD DECK OVER
NORTHWEST WISCONSIN EXPECTED TO MIX OUT LATER THIS MORNING. BASED ON
CURRENT MOVEMENT AND RAP FORECAST 700 MB RH...THE CLOUD DECK TO THE
NORTHWEST LOOKS TO ARRIVE IN NORTHWEST SAUK AND MARQUETTE COUNTY BY
18Z. BY THEN THE DECK IS EXPECTED TO BE SCATTERED OUT.
HIGHS IN THE MID TO UPPER 70S STILL SEEM REASONABLE. RIGHT NOW HAVE
COOLER TEMPS FORECAST NEAR THE LAKE WITH THE EAST WINDS...BUT
MKE...RAC...AND ENW HAVE ALREADY REACHED 70 DEGREES...SO WOULDN/T BE
SURPRISED IF THEY MADE IT TO THE MID 70S THERE AS WELL.
&&
.AVIATION/18Z TAFS/...
MVFR CIGS ACROSS THE WESTERN HALF OF THE FORECAST AREA WILL LIKELY
SCATTER LATE THIS MORNING...WITH BASE HEIGHTS ALSO RISING. VFR
CONDITIONS ARE THEN EXPECTED THIS AFTERNOON THROUGH FRIDAY. COULD
SEE A FEW SHOWERS LATE TONIGHT INTO FRIDAY...BUT ANY PRECIP WOULD
BE LIGHT.
&&
.PREV DISCUSSION... /ISSUED 330 AM CDT THU AUG 8 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE...HIGH
DRY HIGH PRESSURE SETTLES OVER SOUTHERN WISCONSIN TODAY. KEPT
TEMPERATURES CLOSE TO PREVIOUS FORECAST AS 925 MB TEMPERATURES
SUPPORT UPPER 70S INLAND...WITH COOLER READINGS ALONG AND EAST OF
THE KETTLE MORAINE DUE TO LIGHT EAST WINDS OFF OF LAKE MICHIGAN.
NAM IS THE MOST PRODUCTIVE MODEL WITH PRECIPITATION ALONG SURFACE
TROUGH TONIGHT. IN SPITE OF A SHARPER MID LEVEL TROUGH AND
..FRONTOGENETIC FORCING AND Q-VECTOR CONVERGENCE RELATIVELY WEAK
AND WITH OTHER MODELS BARELY SHOWING ANY FORCING OR PCPN WILL HOLD
POPS TO SCATTERED. WILL KEEP PRECIPITATION TYPE AS RAIN SHOWERS WITH
MINIMAL ELEVATED CAPE...THOUGH NAM HAS 200 J/KG...AND EQUILIBRIUM
LEVELS BARELY MAKING IT TO -10C. WHILE A RUMBLE OF THUNDER NOT OUT
OF THE QUESTION TOO LOW A PROBABILITY TO MENTION.
NAM HAS MORE OF A 925 MB THERMAL RIDGE PASSING THRU OVERNIGHT AND IS
ABOUT 1C TO 2C WARMER THAN GFS OR ECMWF. HOWEVER ALL MODELS SHOWING
COOLING TEMPS THROUGH 06Z OR SO THEN LEVELING OUT WITH INCREASING
CLOUDS AND WEAK WAA WITH SWLY WINDS AHEAD OF TROUGH.
FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
THE SURFACE TROUGH IS EXPECTED TO CLEAR SOUTHEAST WI BY 18Z FRIDAY.
KEPT THE SCATTERED SHOWERS IN THERE UNTIL THAT TIME. SOME MODELS
MAINTAIN THAT THE FORCING WILL NOT BE STRONG ENOUGH TO SUSTAIN ANY
SHOWERS INTO SOUTHEAST WI FRIDAY MORNING...SO LOWER CONFIDENCE IN
THE POP VALUES.
EXPECT SOME SUNSHINE TO RETURN IN THE AFTERNOON AS DRY AIR AND HIGH
PRESSURE SPREAD BACK INTO THE REGION. TEMPS WILL REBOUND INTO THE
UPPER 70S.
SATURDAY THROUGH SUNDAY...FORECAST CONFIDENCE HIGH.
SURFACE HIGH PRESSURE WILL SETTLE OVER THE GREAT LAKES REGION ONCE
AGAIN WHILE THE 500MB FLOW REMAINS IN A PERSISTENT PATTERN WITH
RIDGING OVER THE WEST AND SLIGHT TROUGHING OVER THE EAST. 925MB
TEMPS WILL DROP TO AROUND 14C EARLY SATURDAY MORNING OVER SOUTHERN
WI...WITH FRI NIGHT LOWS DROPPING INTO THE LOWER 50S. HIGHS ON
SATURDAY WILL BE IN THE MID 70S ONCE AGAIN AND THERE SHOULD BE
PLENTY OF SUNSHINE. TEMPS WILL BE COOLER NEAR THE SHORE DUE TO A
LAKE BREEZE.
SUNDAY WEATHER WILL BE QUIET...BUT EXPECT INCREASING MID AND HIGH
CLOUDS WITH ANOTHER SYSTEM APPROACHING. HIGHS WILL BE JUST A BIT
WARMER WITH RETURN FLOW AROUND THE DEPARTING SURFACE HIGH.
LONG TERM...
SUNDAY NIGHT AND BEYOND...FORECAST CONFIDENCE MEDIUM.
THE NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE SUNDAY NIGHT
AND MONDAY AS A 500MB TROUGH SWINGS DOWN ACROSS WISCONSIN. THERE IS
DECENT SUPPORT FROM AN 850MB LOW LEVEL JET NOSING INTO WI AND UPPER
DIVERGENCE ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF AN UPPER
JET MOVING ACROSS THE STATE. THE MODELS ARE ALL SHOWING MORE QPF
WITH THIS FEATURE NOW...SO THERE IS INCREASING CONFIDENCE IN AT
LEAST SCATTERED STORM DEVELOPMENT.
SURFACE HIGH PRESSURE WILL SETTLE BACK INTO WISCONSIN BY MONDAY
EVENING AS THE UPPER LEVEL TROUGH AMPLIFIES OVER THE NORTHEAST AND
THE UPPER LEVEL RIDGE AMPLIFIES OVER THE SOUTHWEST. THE ECMWF IS
CONTINUING TO BRING AN UPPER TROUGH THROUGH WI ON WED WHICH WOULD
GENERATE SHOWERS...WHILE THE GFS MAINTAINS UPPER RIDGING. SINCE THE
00Z ECMWF CAME IN DRY ACROSS SOUTHERN WI WITH ONLY LIGHT QPF ACROSS
NORTHERN WI...OPTED TO REMOVE THE MENTION OF PRECIP FROM THE MKX
AREA PER COORDINATION WITH SURROUNDING OFFICES. TEMPS WILL REMAIN
STEADY AND JUST A LITTLE BELOW NORMAL THROUGH THE END OF NEXT WEEK.
AVIATION/12Z TAFS/...
ONCE ANY PATCHY MVFR FOG LIFTS BY MID-MORNING...EXPECTING VFR
CONDITIONS THROUGH THE REMAINDER OF THE FORECAST. WILL SEE BRIEF
MVFR CONDITIONS WITH SCATTERED RAIN SHOWERS AFTER 06Z...MAINLY FOR
KMSN.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...MEB/DDV
TODAY/TONIGHT AND AVIATION/MARINE...REM
FRIDAY THROUGH WEDNESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
615 AM CDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CDT THU AUG 8 2013
AT 3 AM...A RIDGE OF HIGH PRESSURE EXTENDED FROM NORTHWEST
MINNESOTA SOUTHEAST INTO THE UPPER MISSISSIPPI RIVER VALLEY. THIS
HIGH IS PRODUCING LIGHT WINDS ACROSS THE REGION. LOOKING OUT
ACROSS THE MISSISSIPPI RIVER...ONE CAN SEE THAT THE BOUNDARY LAYER
EXTENDS UP TO THE RIDGE TOPS AND IT IS SLOWLY MOISTENING. THERE IS
ALSO SIGNS THAT A STRATUS DECK STARTING TO DEVELOP AROUND 500 TO
600 FEET ABOVE THE VALLEY FLOOR. THE TEMPERATURE AND DEW POINT
SPREAD AT LA CROSSE HAS FALLEN TO 1 DEGREE AND THE VISIBILITY HAS
RECENTLY DROPPED TO 4 MILES. THERE IS STILL SOME CONCERN THAT THE
CLOUDS STREAMING OFF OF THE CONVECTION OVER SOUTH DAKOTA MIGHT
KEEP WIDESPREAD VALLEY FOG FROM DEVELOPING...SO JUST WENT WITH
AREAS OF FOG AT THIS TIME. WILL CONTINUE TO MONITOR THROUGH THE
REMAINDER OF THE NIGHT FROM THE ROAD AND OUR CAM.
FROM TODAY THROUGH TONIGHT...A COLD FRONT...CURRENTLY EXTENDING FROM
DULUTH MINNESOTA TO PIERRE SOUTH DAKOTA...WILL MOVE SLOWLY
SOUTH THROUGH CENTRAL MINNESOTA AND NORTHERN WISCONSIN TODAY...AND
THROUGH MUCH OF OUR FORECAST AREA TONIGHT. AREAS ALONG AND NORTH
OF THE INTERSTATE 90 CORRIDOR WILL REMAIN IN THE RIGHT ENTRANCE
REGION OF A 110 KNOT JET. ONE CAN SEE THE UNDULATIONS ASSOCIATED
WITH THIS JET FROM ABERDEEN SOUTH DAKOTA EAST TO THE TWIN CITIES.
IN ADDITION...THE ML CAPES CLIMB UP TO 500 J/KG IN THIS SAME AREA
BETWEEN 08.21Z AND 09.03Z...AND WEAK 900 TO 700 MB FRONTOGENESIS.
THIS IS ENOUGH FORCING AND INSTABILITY FOR SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO DEVELOP. THE DETERMINISTIC MODELS ARE
MUCH MORE ROBUST WITH THEIR PRECIPITATION CHANCES THAN WHAT THE
ARW OR NMM WOULD SUGGEST. AS A RESULT...JUST WENT WITH A 20 TO
40 PERCENT CHANCE OF RAIN ASSOCIATED WITH THIS FRONT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 251 AM CDT THU AUG 8 2013
ON FRIDAY MORNING...THE COLD FRONT WILL MOVE SOUTH THROUGH
NORTHEAST IOWA AND SOUTHWEST WISCONSIN. AS THIS IS OCCURRING...IT
WILL BE LOSING THE 900 TO 800 MB FRONTOGENESIS...BUT THERE WILL
STILL BE WEAK 800 TO 600 MB FRONTOGENESIS. AS A RESULT...KEPT A
20 TO 30 PERCENT CHANCE RAIN ACROSS THIS AREA.
FROM LATE SATURDAY NIGHT INTO MONDAY MORNING...THE 08.00Z
ECMWF...GEM...AND GFS ARE NOW IN AGREEMENT WITH THEIR TIMING OF A
COLD FRONT THROUGH THE AREA. BOTH THE GEM AND GFS HAVE BEEN VERY
CONSISTENT WITH THE TIMING OF THIS FRONT AND ITS UPPER LEVEL SHORT
WAVE. MEANWHILE THE ECMWF HAS SLOWED ITS PASSAGE OF THIS FRONT BY
NEARLY 24 HOURS FROM ITS 07.12Z RUN. AS A RESULT...MUCH UNCERTAINTY
STILL REMAINS WITH THIS SYSTEM. DUE TO THIS...STAYED WITH THE ALL
BLEND PRECIPITATION CHANCES. WHILE THERE HAS BEEN ISSUES WITH
TIMING...THE MODELS HAVE BEEN CONSISTENTLY SHOWING THAT THERE WILL
BE RATHER LIMITED 925 TO 850 MB MOISTURE TRANSPORT INTO THE
AREA...AND THAT THE ML CAPES WILL REMAIN LESS THAN 1000 J/KG. WITH
THE 0-3 KM AND 0-6 KM MARGINAL SHEAR...NOT ANTICIPATING ANY SEVERE
WEATHER WITH THIS FRONTAL PASSAGE.
FROM TUESDAY NIGHT INTO WEDNESDAY...BOTH THE GFS AND ECMWF ARE
SHOWING THAT MUCH OF THE FORECAST AREA WILL BE STILL UNDER THE
INFLUENCE OF A CANADIAN HIGH PRESSURE SYSTEM. THIS TREND HAS
BEEN RATHER CONSISTENT DURING THE LAST 3 RUNS OF ECMWF. THE ONLY
PLACE THAT MAY SEE SOME SHOWERS AND THUNDERSTORMS IS NORTH OF THE
INTERSTATE 90 WHERE A SHORT WAVE MOVING THROUGH NORTHERN MINNESOTA
AND UPPER MICHIGAN MAY PRODUCE ENOUGH LIFT AND MOISTURE TRANSPORT
INTO THE AREA FOR SOME SCATTERED SHOWERS AND THUNDERSTORMS TO
DEVELOP. SINCE IT LOOKS DRY...REMOVED THE PRECIPITATION CHANCES
THAT THE ALL BLEND PRODUCED ACROSS THE ENTIRE AREA ON TUESDAY
NIGHT...AND ACROSS NORTHEAST IOWA...AND CENTRAL AND SOUTHWEST
WISCONSIN ON WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 615 AM CDT THU AUG 8 2013
VALLEY FOG STILL A CONCERN AT KLSE. WHILE SFC WINDS HAVE BEEN LIGHT
TO CALM...JUST OFF THE SFC THE WINDS CONTINUE TO STIR...HAMPERING
DENSE FOG FORMATION. RAP BUFKIT SOUNDINGS HAVE TRENDED LIGHTER WITH
THE NEAR SFC WINDS...AND WINDS WERE LIGHT AT THE NWS ARX
OFFICE...600 FT OFF THE VALLEY FLOOR. VISUAL INTO THE VALLEY SHOWS
SOME LOW STRATUS HANGING ABOVE THE MISSISSIPPI. T/TD SPREAD HAS HELD
AT 2 F THROUGH THE OVERNIGHT. STILL...SEE SOME POTENTIAL IT COULD
DROP TO 1SM OR SO IN THE 12-14Z TIME FRAME...AND IF SO...WOULD
QUICKLY MIX OUT AFTER THAT. WILL MONITOR TRENDS UP TO TAF ISSUANCE.
BCFG MIGHT MOST APPROPRIATE.
EXPECT INCREASING CLOUDS FROM THE WEST TODAY INTO
TONIGHT...ASSOCIATED WITH AN APPROACHING SFC TROUGH AND UPPER LEVEL
ENERGY. ENOUGH LIFT TO TRIGGER SCT SHRA/TS...ALTHOUGH THE TS WILL
LIKELY BE MORE ISOLATED AS INSTABILITY IS LIMITED AND CONFINED TO
THE LATE AFTERNOON/EVENING HOURS. WILL CONTINUE VCSH MENTION IN THE
TAFS FOR NOW...ALLOWING FOR INCREASED CONFIDENCE TO REFINE TIMING
AND CONDITIONAL WORDING AS NEEDED. BUFKIT SOUNDINGS AND RH FIELDS DO
POINT TO A LOWERING OF CIG DECK/SWITCH IN WINDS AS THE TROUGH SINKS
SOUTH OVERNIGHT. WILL TREND THIS WAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM....BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
533 AM MDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 312 AM MDT THU AUG 8 2013
AREAS OF FOG HAVE DEVELOPED ACROSS FAR SOUTHEAST WY THIS MORNING IN
RESPONSE TO MOIST SOUTH-TO-SOUTHEAST LLVL FLOW ALONG AND EAST OF THE
LARAMIE RANGE. VSBYS AT KCYS HAVE BEEN REDUCED TO ONE QUARTER OF A
MILE AT TIMES OVER THE PAST FEW HOURS...AND AREA WEBCAMS SHOW DENSE
FOG TO BE FAIRLY WIDESPREAD ACROSS CENTRAL AND EASTERN PORTIONS OF
LARAMIE COUNTY. MAIN QUESTION IS HOW LONG THIS FOG WILL LAST AS
WINDS MAY DEVELOP A SLIGHT SOUTHWEST COMPONENT EARLY THIS AM...WHICH
WOULD TEND TO SCOUR OUR EXISTING LLVL MOISTURE. ASSOCIATED -DZ COULD
ALSO LIMIT DENSE FOG POTENTIAL. LATEST HRRR RUNS STILL SHOW VERY LOW
VSBYS THROUGH ABOUT 15Z THOUGH...SO HAVE ISSUED A DENSE FOG ADVISORY
FOR THE I80 CORRIDOR BETWEEN THE SUMMIT AND NEBRASKA STATE LINE
THROUGH MID AM TO COVER AT LEAST THE NEAR TERM THREAT FOR HAZARDOUS
TRAVEL.
EVEN IF FOG DOES NOT PERSIST...LOW STRATUS SHOULD CREATES A FORECAST
HEADACHE FOR THU AFTN AND EVE. 11-3.9 MICROMETER IR CHANNEL SUGGESTS
LLVL CLOUDS ARE BECOMING RATHER WIDESPREAD FROM THE LARAMIE RANGE
EWD INTO THE WESTERN NE PANHANDLE. MIGHT BE TOUGH TO BURN OFF CLOUD
COVER TODAY AS EASTERLY UPSLOPE FLOW BECOMES ESTABLISHED OVER THE
HIGH PLAINS. GIVEN THIS AND 700 MILLIBAR TEMPS TO BE PROGGED ABOUT
1-2 DEG COOLER THAN WED...HAVE TRENDED A FEW DEGREES BELOW MOS GUID
FOR FCST HIGHS WHERE CLOUDS SHOULD BE THICKEST. NATURALLY THIS ALSO
LEADS TO QUESTIONS WITH INSTABILITY AND POSSIBLE CONVECTION LATER
IN THE DAY ON TOP OF AN ALREADY COMPLICATED SYNOPTIC SETUP.
A DIRTY UPPER-LEVEL RIDGE WILL BUILD INTO SOUTH CENTRAL WY THIS AFTN
WITH NUMEROUS MIDLVL DISTURBANCES LIKELY INTERACTING WITH MONSOONAL
MOISTURE IN THE 700-300 MILLIBAR LAYER. THIS...ALONG WITH UPPER-LEVEL
DIVERGENCE IN THE RIGHT REAR QUADRANT OF A MIDWEST US JET STREAK AND
UPSLOPING LLVL FLOW SHOULD CONTRIBUTE TO SUFFICIENT LIFT FOR SHOWER
AND TSTM DEVELOPMENT LATER TODAY. THE BEST DYNAMICS APPEAR TO DROP
TO THE SOUTH WITH A STRONGER WAVE EVIDENT ON WATER VAPOR SATELLITE
OVER EASTERN UT AND WESTERN CO...WHICH COULD LIMIT OVERALL COVERAGE
OF PCPN IN OUR CWA. ESSENTIALLY BETWEEN SYSTEMS...FLOW ALOFT SHOULD
BE WEAK WITH ONLY AROUND 10-15 KTS OF 700-500 MILLIBAR FLOW. LESS
THAN 30 KTS OF EFFECTIVE SHEAR SHOULD KEEP SEVERE STORMS AT BAY...
EVEN IF THE MUCH MORE UNSTABLE NAM WOULD VERIFY WITH SURFACE CAPES
IN EXCESS OF 1500 J/KG. THINKING INSTABILITY WILL BE MODEST AT BEST
THOUGH WITH LIMITED DAYTIME HEATING...BUT MIDLVL COOLING WILL YIELD
SUFFICIENT ELEVATED INSTABILITY FOR TSTM DEVELOPMENT. OVERALL THREAT
FROM CONVECTION WILL BE HEAVY RAIN FROM SLOW MOVING STORMS...THOUGH
PWATS ARE NOT PARTICULARLY HIGH WITH SOME MOISTURE BEING ROBBED BY
THE SYSTEM TO THE SOUTH.
TRYING NOT TO SOUND LIKE A BROKEN RECORD...PERSISTENCE IS THE NAME
OF THE GAME AS WE HEAD INTO FRIDAY. SEVERAL WEAK DISTURBANCES ARE
LIKELY TO TRAVERSE THE FLOW ALONG THE EDGE OF THE CENTRAL ROCKIES
RIDGE...MOST OF WHICH ARE TOO WEAK TO ACCURATELY PREDICT WITH ANY
REASONABLE DEGREE OF ACCURACY. WITH ABUNDANT SUBTROPICAL MOISTURE
REMAINING IN PLACE OVER THE AREA...OVERALL PATTERN FAVORS ANOTHER
COOL DAY WITH SCATTERED SHOWERS AND STORMS WITH CONTINUED UPSLOPE
FLOW IN THE LLVLS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM MDT THU AUG 8 2013
ACTIVE WEATHER PATTERN TO REMAIN IN PLACE THROUGH THE EXTENDED
FORECAST PERIOD. THE ONLY POTENTIAL CHANGE IS FOR THE UPPER LEVEL
RIDGE CURRENTLY OVER THE ROCKIES TO EXPAND NORTHWARD. BOUTS OF
MONSOON MOISTURE SHOULD CONTINUE TO SNEAK UNDER THE RIDGE AND
INFLUENCE THE FORECAST AREA WITH CHANCES FOR AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS...WHILE TEMPERATURES SHOULD BE NEAR TO
SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. WITH THE RIDGE IN PLACE
UPPER LEVEL WINDS WILL BE ON THE LIGHT SIDE WHICH SHOULD SERVE TO
MINIMIZE SEVERE WEATHER CHANCES. HIGH TEMPERATURES WILL MAINLY BE
IN THE 80S WITH LOWS IN THE 50S FOR AREAS OUTSIDE OF THE
MOUNTAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 412 AM MDT THU AUG 8 2013
WIDESPREAD LOW CLOUDS AND FOG WILL BE FOUND OVER SOUTHEAST WYOMING
MAINLY EAST OF THE LARAMIE RANGE EARLY THIS MORNING WITH AREAS OF
DENSE FOG. CEILINGS WILL DROP TO ONLY A FEW HUNDRED FEET AGL WITH
VISIBILITIES 1/4 MILE OR LESS AT TIMES. FOG WILL ALSO BE FOUND
OVER PORTIONS OF THE NEBRASKA PANHANDLE. FOG WILL BEGIN TO LIFT
AFTER SUNRISE BUT SOME FOG AND LOW CLOUDS TO HANG THROUGH LATE
THIS MORNING. ATTENTION TURNS TO CHANCES FOR THUNDERSTORMS THIS
AFTERNOON. EXPECTING SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING THIS AFTERNOON BUT ACTUAL COVERAGE WILL DEPEND ON HOW
LONG THE FOG HOLDS THIS MORNING. GUSTY WINDS AND SMALL HAIL
POSSIBLE WITH SOME THUNDERSTORMS THIS AFTERNOON AND EVENING. FOG
MAY REDEVELOP AFTER MIDNIGHT TONIGHT IN THE EAST.
&&
.FIRE WEATHER...
ISSUED AT 312 AM MDT THU AUG 8 2013
FIRE WEATHER CONCERNS WILL BE MINIMAL OVER THE NEXT FEW DAYS AS
MONSOON MOISTURE REMAINS IN PLACE OVER THE REGION. TEMPERATURES
WILL BE NORMAL OR SLIGHTLY BELOW WITH AT LEAST SCATTERED SHOWERS
AND STORMS EACH AFTERNOON AND EVENING THROUGH FRIDAY. DRYING IS
EXPECTED ACROSS WESTERN CARBON AND CONVERSE COUNTIES DURING THE
WEEKEND WITH AFTERNOON RELATIVE HUMIDITY VALUES FALLING BELOW 15
PERCENT. HOWEVER WINDS ARE EXPECTED TO REMAIN BELOW THE CRITICAL
THRESHOLDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...DENSE FOG ADVISORY UNTIL 9 AM MDT THIS MORNING FOR WYZ117>119.
NE...NONE.
&&
$$
SHORT TERM...HAMMER
LONG TERM...LIEBL
AVIATION...LIEBL
FIRE WEATHER...HAMMER
AREA FORECAST DISCUSSION
NWS EUREKA CA
349 PM PDT THU AUG 8 2013
.SYNOPSIS...AN UPPER LEVEL LOW CONTINUES TO SIT JUST OFFSHORE.
THIS MAY BRING SOME ISOLATED THUNDERSTORMS TO THE INLAND AREAS
THIS EVENING AND TONIGHT...MAINLY NORTH OF HIGHWAY 36. THERE IS A
SLIGHT CHANCE OF THUNDERSTORMS ALONG THE COAST TONIGHT NORTH OF
ORICK. FRIDAY THUNDERSTORMS ARE POSSIBLE AGAIN BEFORE HIGH
PRESSURE RETURNS FOR THE WEEKEND.
&&
.SHORT TERM...UPPER LEVEL LOW CONTINUES TO SIT AND SPIN THIS
AFTERNOON. IT CURRENTLY IS CENTERED SOUTHWEST OF CAPE MENDOCINO.
THIS IS CONTINUING TO BRING SHOWERS AND THUNDERSTORMS TO NORTHERN
CA. HOWEVER...IN THE EUREKA CWA CONVECTION IS STRUGGLING. THIS
LOOKS TO BE DUE A AN AREA OF POOR LAPSE RATES AROUND 600 MB. THE
NAM AND RUC ARE STILL INDICATING THAT LATER THIS EVENING A FEW
SHOWERS WILL POP UP...MAINLY IN TRINITY COUNTY. TRIMMED BACK POPS
SLIGHTLY FOR THIS AFTERNOON...BUT MAINLY LEFT THINGS ALONE WITH
ISOLATED TO SCATTERED COVERAGE. ALONG THE COAST SKIES HAVE
PARTIALLY CLEARED OUT WITH THE INCREASED MIXING...BUT EXPECT
CLOUDS WILL RETURN THIS EVENING. THIS INCREASED MIXING HAS ALSO
LIFTED TEMPERATURES INTO THE LOW 60S AT THE COAST.
LATE TONIGHT INTO FRIDAY MORNING THE MODELS ARE SHOWING A
SHORTWAVE ROTATING AROUND THE LOW. MODELS ARE INDICATING SOME
ELEVATED INSTABILITY WITH THIS SO IT MAY KICK OFF A FEW
THUNDERSTORMS. THE BEST CHANCE WILL BE NORTH OF HWY 299. SINCE
THESE ARE ELEVATED SEE NO REASON IF THEY DO FORM THAT THEY WONT
MAKE IT ALL THE WAY THE COAST. AS WITH MOST NOCTURNAL
THUNDERSTORMS IN THIS AREA CONFIDENCE IS LOW. THERE IS AN OUTSIDE
CHANCE A FEW COULD MAKE IT AS FAR SOUTH AS EUREKA...BUT WAS NOT
CONFIDENT ENOUGH IN THIS TO PUT THEM IN THE FORECAST. FRIDAY
AFTERNOON THERE IS AN ADDITIONAL CHANCE FOR THUNDERSTORMS OVER THE
INLAND AREAS. LAPSE RATES LOOK MARGINAL...SO LEFT THE FORECAST
BASICALLY UNCHANGED. ALONG THE COAST EXPECT THERE WILL BE CLEARING
AGAIN IN THE AFTERNOON AND TEMPERATURES MAY REACH THE LOW 60S ONCE
AGAIN. INLAND TEMPERATURES WILL BE SIMILAR TO TODAY AS WELL.
SATURDAY AND SUNDAY THE LOW STARTS TO PULL OFF TO THE NORTH AND
THE AIR STABILIZES. SATURDAY THERE IS AN SLIGHT CHANCE FOR SOME
THUNDERSTORMS ALONG THE SISKIYOU/TRINITY COUNTY...BUT EVEN THAT IS
DOUBTFUL. TEMPERATURES INLAND WILL GRADUALLY START TO WARM AGAIN
AS THE LOW PULLS OFF THE NORTH. ALONG THE COAST THERE MAY BE SOME
CLEARING EACH AFTERNOON...BUT THIS WILL LIKELY BE BRIEF. MKK
&&
.LONG TERM(MONDAY THROUGH THURSDAY)...
NOT MUCH TO SAY REGARDING THE FORECAST NEXT WEEK. IT SHOULD BE A
PRETTY QUIET PERIOD OVERALL, AND WHILE WE LEFT SOME `GHOST POPS`
OVER THE MTS OF ERN MENDO/TRINITY MON PM, THE ATMOSPHERE LOOKS
INCREASINGLY DRY AND STABLE HEADING THROUGH THE WEEK. TEMPERATURES
WILL WARM TO NEAR SEASONABLE LEVELS WITH HIGHS IN THE LOW 90S ACROSS
THE WARMER INTERIOR VALLEYS. AT THE COAST, SOME INCREASE IN
NORTHERLY WINDS AND THE LACK OF A STRONG RIDGE OF HIGH PRESSURE
LENDS HOPE FOR SOME PARTIALLY SUNNY AFTERNOONS, ESPECIALLY ALONG THE
MENDOCINO COAST. HOWEVER GIVEN THE TIME OF YEAR, AND STILL PLENTY OF
BOUNDARY LAYER MOISTURE AROUND WITH NORTHERLY AND ONSHORE FLOW,
MORNING AND OVERNIGHT LOW CLOUDS AND FOG WILL REMAIN PERSISTENT. AAD
&&
.AVIATION...RELATIVELY LOW CONFIDENCE FORECAST TONIGHT. CURRENT
VISIBLE IMAGERY SHOWS 1000-1500FT DECK OVER THE INLAND COASTAL HILLS
OF HUMBOLDT COUNTY WITH SCATTERED LOWER STRATUS IN PATCHES ALONG THE
MENDOCINO COAST AND DEL NORTE COUNTY NEAR KCEC. EXPECT THE CLEAR
SPOTS TO FILL BACK BETWEEN 02Z AND 05Z AND GO BELOW 1000FT BY
8Z-12Z. HOWEVER WITH THE UPPER LOW MOVING THROUGH WOULD NOT BE
SURPRISED TO SEE THE CEILINGS LIFT A BIT BEFORE COMING BACK DOWN
CLOSER TO DAWN TOMORROW. HIGHER CONFIDENCE THAT VSBYS WILL STAY
MOSTLY UNRESTRICTED, DESPITE THE GUIDANCE SHOWING OTHERWISE.
CLEARING TOMORROW SHOULD BE A BIT EASIER TO COME BY WITH THE LESS
STABLE ENVIRONMENT, BUT DO NOT EXPECT MUCH MORE THAN A FEW HOURS
WITH LIGHT NORTHERLY WINDS IN THE BL NOT SUPPORTING MUCH MIXING.
CIGS SHOULD AT LEAST BE ABOVE 1000 OR 1500 FT AFTER EARLY TO MID
MORNING. AWAY FROM THE COAST...THERE WILL BE A THREAT FOR SCATTERED
SHOWERS AND A STRAY THUNDERSTORM OR TWO OVER THE SISKIYOUS OR
TRINITY ALPS. SMOKE NEAR FIRES IN SRN SISKIYOU COUNTY WILL CONTINUE
TO LOWER VISIBILITY IN LOCALIZED AREAS. AAD
&&
.MARINE...VERY LITTLE CHANGE TO THE PREVIOUS FORECAST. SEAS WERE
RUNNING 2 TO 4 FEET ACROSS THE COASTAL WATERS AS OF THIS WRITING,
WITH VERY LIGHT WINDS WITHIN 5 TO 10 NM OF SHORE. NO ASCAT PASS
YET TODAY, BUT NORTHERLY WINDS ARE PROBABLY PICKING UP A BIT MORE
ACROSS THE OUTER WATERS BEYOND 10 NM, ON THE ORDER OF 10 TO 15
KNOTS, ESPECIALLY TO THE LEE OF CAPE MENDOCINO. ISOLATED SHOWER
ACTIVITY WILL BE POSSIBLE LATER TONIGHT AND TOMORROW MORNING. WITH
THE UPPER LOW STILL TRACKING THROUGH, BUT DO NOT EXPECT ANY
LIGHTNING AS THE BETTER DYNAMICS AND FORCING SHIFT EAST AND NORTH.
AS THE UPPER LOW PASSES BY AND RIDGING TRIES TO BUILD BACK IN,
NORTHERLY WINDS WILL INCREASE BY SUNDAY OR MONDAY. HOWEVER, WE ARE
THINKING 20-25 KTS OVER THE SRN OUTER WATERS AND NEAR CAPE
MENDOCINO AT WORST, AS THE RIDGE REMAINS FLAT AT BEST, AND HIGH
PRESSURE OFFSHORE REMAINS WEAK. OTHERWISE, OUTSIDE OF LOCALLY
GENERATED LOW WAVES GENERATED BY THESE NORTHERLIES, A NW SWELL
AROUND 10-12 SEC PERIOD WILL PEAK AT ABOUT 4 FT ON SATURDAY BEFORE
GRADUALLY DECAYING. A 1-2 FT SOUTHERLY SWELL NEAR 14 SEC PERIOD
MAY ALSO BE NOTICEABLE WHERE THE WINDS AND SEAS ARE OTHERWISE
LIGHT AND LOW. AAD
&&
.FIRE WEATHER...A FEW SHOWERS HAVE STARTED TO POP UP THIS
AFTERNOON SO IT LOOKS REASONABLE THAT WE WILL GET SOME
STRIKES...ALTHOUGH THE EXACT COVERAGE AND LOCATION MAY BE
SLIGHTLY LESS THAN FORECASTED. LEFT THE RED FLAG WARNING IN PLACE
FOR THIS EVENING. LATE TONIGHT A SHORTWAVE ROTATING AROUND THE LOW
LOOKS TO SPARK OFF SOME THUNDERSTORMS. EXPECT THESE WILL MAINLY BE
NORTH OF HWY 299 SO UPGRADED THE FIRE WEATHER WATCHES TO WARNINGS
IN THE NORTH AND CANCELLED THE WATCHES IN THE SOUTH. CONFIDENCE
REMAINS LOW ON THIS NOCTURNAL CONVECTION. FRIDAY AFTERNOON SOME
CONVECTION MAY RETURN...HOWEVER THE LAPSE RATES ALOFT LOOK A BIT
MARGINAL SO LEFT THE FIRE WEATHER WATCH IN PLACE. THE BEST CHANCE
FOR THUNDERSTORMS LOOK TO BE ALONG THE SISKIYOU/TRINITY COUNTY
BORDER. FOR THE WEEKEND THE THREAT LOOKS TO DIMINISH AS THE LOW
PULLS AWAY SO IT IS UNLIKELY THAT ANY ADDITIONAL WATCHES OR
WARNINGS WILL BE ISSUED FOR THEN. MKK
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...RED FLAG WARNING UNTIL 11 PM PDT THIS EVENING CAZ076.
FIRE WEATHER WATCH FROM FRIDAY MORNING THROUGH FRIDAY
EVENING CAZ003-004-076.
RED FLAG WARNING UNTIL 11 AM PDT FRIDAY CAZ003-004.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA
FOLLOW US ON FACEBOOK AND TWITTER AT:
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HTTP://WWW.TWITTER.COM/NWSEUREKA
AREA FORECAST DISCUSSION
NWS ALBANY NY
134 PM EDT THU AUG 8 2013
.SYNOPSIS...
AHEAD OF A SLOW MOVING COLD FRONT...A MUGGY AIR MASS IN PLACE WILL
ALLOW FOR SOME SHOWERS AND THUNDERSTORMS THIS AFTERNOON. AS THE
COLD FRONT MOVES ACROSS THE REGION...ADDITIONAL SHOWERS AND
THUNDERSTORMS...SOME WITH HEAVY RAINFALL...WILL OCCUR TONIGHT INTO
TOMORROW. DRIER AND LESS HUMID CONDITIONS WILL RETURN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM EDT...RADARS INDICATING STILL NO REAL CONVECTION HAS
DEVELOPED OVER THE AREA. THERE WERE PLENTY OF CU AND SOME HIGH
CLOUDS AND MSAS ANALYSIS INDICATED SURFACE BASED CAPES UP TO 1500
J/KG.
THE LATEST HRRR AND HIRES WRF MODELS CONTINUE TO INDICATE CONVECTION
WILL DEVELOP DURING THE AFTERNOON.
FORCING REMAINS WEAK BUT ANY WEAK BOUNDARIES INCLUDING A DEWPOINT
BOUNDARY WELL TO OUR WEST IN SW NY...AND EVEN TERRAIN ASPECT COULD
ALLOW FOR SOME CONVECTION TO DEVELOP LATER IN THE AFTERNOON. THERE
ARE BREAKS OF SUNSHINE...ALBEIT NOT MANY...THAT COULD HELP THE
CAUSE.
FOR THIS UPDATE...PUSHED BACK THE TIME OF DEVELOPMENT (LATER) AND
LOWERED POPS A TAD...GENERALLY HELD TO THE 30-50 PERCENT FOR LATE
AFTERNOON. THE 12Z ALY/MODEL SOUNDINGS DO INDICATE A DISTINCT MID
LEVEL DRY AREA THAT COULD ALLOW FOR MOMENTUM OF MODEST WINDS ALOFT
TO MIX DOWN...ALTHOUGH THEY ARE ONLY AROUND 40 KTS AROUND THE
20,000+ LEVEL. WILL LEAVE THEM IN
KEPT HIGH TEMPERATURES VERY SIMILAR TO BEFORE DESPITE THE FACT THAT
SOME AREAS WERE ALREADY APPROACHING HIGH TEMPERATURES. THE CLOUDS
SHOULD KEEP HIGH TEMPERATURES FROM RISING MUCH MORE. LOOK FOR HIGHS
WITHIN A FEW DEGREES OF 80. HOWEVER DEWPOINTS 65 TO 70 WILL ACTUALLY
MAKE THESE READINGS FEEL A TAD HIGHER.
SOME OF THE MORE SPECIFIC PARAMETERS AFFECTING CONVECTIVE MODE
THIS AFTERNOON AND EVENING ARE DESCRIBED IN THE PREVIOUS AFD
BELOW...
WITH SFC CAPE VALUES EXPECTED TO REACH AROUND 1000 J/KG...AND 500
HPA WINDS OF AROUND 25-30 KTS IN PLACE...THERE MAY BE JUST ENOUGH
INGREDIENTS IN PLACE FOR A FEW STRONG STORMS ACROSS OUR AREA.
WHILE WIDESPREAD SVR STORMS IS NOT ANTICIPATED...IT/S POSSIBLE
THAT A ROGUE STORM OR TWO COULD PRODUCE GUSTY WINDS...ESP
CONSIDERING INCREASING HIGH PWAT VALUES AROUND 1.50 INCHES
MAY ALLOW FOR A PRECIP LOADING INDUCED WIND GUST WITHIN ANY HEAVY
SHOWER OR THUNDERSTORM. SPC HAS PLACED OUR AREA IN A 5% PROB FOR SVR
WX...AND THIS LOOKS TO BE RIGHT. WE WILL MENTION THE POTENTIAL FOR
GUSTY WINDS IN THE ZONES AND HWO PRODUCT.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
THE SFC FRONT WILL STALL CLOSE TO OR OVER OUR AREA TONIGHT INTO
FRIDAY WHILE THE UPPER LEVEL ENERGY SLOWLY BARRELS ACROSS ONTARIO.
A STRONG JET STREAK AT 250 HPA OF AROUND 125 KTS WILL UNDERCUT THE
UPPER LEVEL LOW AND BE SITUATED OVER THE UPPER GREAT LAKES AND
SOUTHERN CANADA. WITH THE UPSTREAM JET STREAK...HIGH MOISTURE IN
PLACE...AND PROXIMITY OF THE SFC BOUNDARY...SHOWERS AND
THUNDERSTORMS LOOK LIKELY TONIGHT INTO FRIDAY OVER MUCH OF THE
REGION. A WEAK SURFACE WAVE MAY DEVELOP ALONG THE BOUNDARY FOR
FRIDAY AS WELL...WHICH MAY HELP INCREASE COVERAGE OF
SHOWERS/STORMS...AS WELL AS HELP MOVE THE BOUNDARY SOUTHEAST
SOMEWHAT BY LATE IN THE DAY FRIDAY.
IT WILL BE DIFFICULT TO SAY EXACTLY WHERE AND WHEN
SHOWERS/TSTMS WILL TRACK THROUGH THE PERIOD. WITH THE CONVECTIVE
NATURE OF THE PRECIP...THERE IS THE POTENTIAL FOR QPF AMOUNTS TO
BE RATHER VARIABLE ACROSS THE REGION. HOWEVER WE CAN SAY WITH
CERTAINTY THAT WITH PWATS STILL AROUND TWO INCHES...HEAVY RAINFALL
WILL BE A POSSIBILITY WITH ANY SHOWER/STORM...AND WE WILL CONTINUE
TO MENTION THIS IN BOTH THE GRIDS AND HWO. SEE OUR HYDRO SECTION
ON HOW WE EXPECT THIS RAINFALL TO IMPACT THE HSA.
SIMILAR TO TODAY /THURS/...SPC HAS OUR REGION IN A /SEE TEXT/ FOR
STORMS ON FRIDAY WITH A 5% PROB FOR SVR IN PLACE. AGAIN...LIMITED
INSTABILITY AND WEAK LAPSE RATES WILL PREVENT WIDESPREAD SVR
WX...BUT ANY BREAKS IN THE CLOUDS WILL INCREASE THE THREAT FOR A
ROGUE STRONGER STORM.
MIN TEMPS TONIGHT WILL BE WARM AND MUGGY...WITH MID 60S TO LOW 70S
EXPECTED. MAX TEMPS ON FRIDAY WILL GENERALLY BE IN THE 70S TO NEAR
80.
THE FRONT WILL FINALLY START TO MOVE AWAY ON FRIDAY NIGHT. SOME
SHOWERS MAY LINGER ACROSS SOUTHEASTERN AREAS INTO FRIDAY
EVENING...BUT THE ENTIRE REGION SHOULD BE CLEARED OUT BY SAT
MORNING. MIN TEMPS ON FRI NIGHT WILL STILL BE IN THE 60S IN MOST
PLACES.
DRIER AND LESS HUMID CONDITIONS ARE EXPECTED SAT INTO SAT NIGHT AS
SFC HIGH PRESSURE BUILDS INTO THE REGION FROM THE GREAT LAKES. MAX
TEMPS ON SAT WILL BE IN THE 70S TO LOW 80S AND MIN TEMPS SAT NIGHT
WITH BE IN THE 40S AND 50S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MAINLY DRY WEATHER IS EXPECTED DURING THE LONG TERM PERIOD WITH ONLY
A CHANCE OF SHOWERS AND THUNDERSTORMS ON TUESDAY.
SUNDAY THROUGH MONDAY NIGHT...EXPECT DRY CONDITIONS AS A RIDGE OF
HIGH PRESSURE BUILDS ACROSS THE REGION AT THE SURFACE. EXPECT HIGHS
ON SUNDAY AND MONDAY TO RANGE FROM THE LOWER 70S NORTHWEST TO THE
LOWER 80S SOUTHEAST. LOWS SATURDAY NIGHT ARE EXPECTED TO RANGE FROM
THE LOWER 40S NORTHWEST TO MID 50S SOUTHEAST WITH LOWS SUNDAY NIGHT
RANGING FROM THE UPPER 40S NORTHWEST TO UPPER 50S SOUTHEAST AND LOWS
MONDAY NIGHT IN THE 50S TO LOWER 60S.
TUESDAY...A WEAK TROUGH OF LOW PRESSURE WILL SLIDE SOUTHEAST FROM
THE EASTERN GREAT LAKES AND SOUTHEAST CANADA. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF THIS FEATURE WITH SB
CAPES RISING TO BTWN 500 AND 1000 J/KG HIGHS ON TUESDAY ARE EXPECTED
TO BE IN THE 70S TO AROUND 80 WITH A FEW AREAS ACROSS THE SRN
ADIRONDACKS IN THE UPPER 60S.
TUESDAY NIGHT AND WEDNESDAY...EXPECT A RETURN TO DRY CONDITIONS AS
HIGH PRESSURE BUILDS BACK INTO THE NORTHEAST. LOWS TUESDAY NIGHT ARE
EXPECTED TO RANGE FROM THE UPPER 40S NORTHWEST TO UPPER 50S
SOUTHEAST WITH HIGHS ON WEDNESDAY RANGING FROM THE UPPER 60S
NORTHWEST TO UPPER 70S SOUTHEAST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
SOME ISOLATED SHOWERS AND THUNDERSTORMS ARE BEGINNING TO FORM IN
THE EASTERN CATSKILLS AND COULD TRACK TOWARD KPOU LATER THIS
AFTERNOON. OTHERWISE...VERY LITTLE ORGANIZED FORCING TO TRIGGER
SHOWERS AND THUNDERSTORMS IN OTHER AREAS THROUGH THIS
AFTERNOON...EVEN INTO EARLY THIS EVENING. THERE ARE SCATTERED
VARIABLE BROKEN CLOUDS NEAR AND ABOVE 3000 FEET ACROSS THE REGION
AND SOME ISOALTED TO SCATTERED SHOWERS AND THUNDERSTORMS COULD
FORM IN THE WESTERN MOHAWK VALLEY OR SOUTHERN ADIRONDACKS THAT
COULD TRACK TOWARD KALB...KGFL AND KPSF THIS EVENING. MORE
ORGANIZED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO TRACK INTO THE
REGION FROM THE GREAT LAKES OVERNIGHT INTO TOMORROW MORNING WITH
SOLID MVFR CEILINGS AND VISIBILITIES TONIGHT INTO TOMORROW...
POSSIBLY DROPPING INTO IFR. UNTIL CONFIDENCE IN IFR IS HIGHER...
KEEPING LOW MVFR TONIGHT AND TOMORROW MORNING WITH SHOWERS.
SOUTH TO SOUTHWEST WINDS AT 10 MPH OR LESS THIS AFTERNOON SHOULD
BECOMING LIGHT SOUTH TONIGHT AND THEN INCREASE AGAIN TO 6-10 KT
TOMORROW MORNING.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY: HIGH OPERATIONAL IMPACT. LIKELY
SHRA...TSRA.
SATURDAY THROUGH MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WX ISSUES ARE ANTICIPATED OVER THE NEXT SEVERAL DAYS.
SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY
THROUGH TOMORROW NIGHT. DRY WEATHER WILL RETURN OVER THE WEEKEND.
RH VALUES WILL ONLY DROP TO 65 PERCENT THIS AFTERNOON WITH
SOUTHERLY WINDS OF 5 TO 10 MPH. RH VALUES WILL RETURN TO NEAR 100
PERCENT TONIGHT WITH SOUTH WINDS AT 5 MPH. RH VALUES GENERALLY
GREATER THAN 70 PERCENT WILL BE IN PLACE FOR TOMORROW WITH RAIN
SHOWERS LIKELY.
&&
.HYDROLOGY...
SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE REGION TODAY
THROUGH TOMORROW NIGHT AS A COLD FRONT MOVES ACROSS THE REGION.
THE MOST LIKELY PERIOD FOR SEEING RAINFALL WILL BE TONIGHT INTO
FRIDAY. AREAS SOUTH AND EAST OF THE CAPITAL REGION LOOK
TO SEE THE HEAVIEST RAINFALL...AS THE FRONTAL BOUNDARY WILL STALL
CLOSE TO THIS AREA...AND A WAVE OF LOW PRESSURE WILL MOVE ALONG
THE BOUNDARY.
WITH PWATS NEAR TWO INCHES AND DEWPOINTS IN THE MID 60S TO NEAR
70...HEAVY RAINFALL WILL BE POSSIBLE WITHIN ANY OF THE SHOWERS AND
THUNDERSTORMS. FFG VALUES LOOK TO BE AT TYPICAL VALUES FOR EARLY
AUGUST...AND IT WILL REQUIRE ABOUT TWO TO THREE INCHES OF RAINFALL
IN A ONE HOUR PERIOD TO CAUSE FLASH FLOODING. DEPENDING ON WHERE
SHOWERS AND THUNDERSTORMS TRACK...MINOR FLOODING OF URBAN...POOR
DRAINAGE...AND LOW LYING AREAS WILL BE POSSIBLE THROUGH
FRIDAY...MAINLY FOR AREAS SOUTH AND EAST OF THE CAPITAL REGION.
DRIER WEATHER WILL RETURN TO THE REGION OVER THE WEEKEND. WHILE
THERE MAY BE SOME IN BANKS RISES ON MAIN STEM RIVERS AND STREAMS LATE
THIS WEEK...DRY WEATHER OVER THE WEEKEND WILL ALLOW THESE FLOWS TO
RECEDE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/NAS
NEAR TERM...HWJIV/NAS
SHORT TERM...FRUGIS
LONG TERM...11
AVIATION...NAS
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
100 PM EDT THU AUG 8 2013
.SYNOPSIS...
AHEAD OF A SLOW MOVING COLD FRONT...A MUGGY AIR MASS IN PLACE WILL
ALLOW FOR SOME SHOWERS AND THUNDERSTORMS THIS AFTERNOON. AS THE
COLD FRONT MOVES ACROSS THE REGION...ADDITIONAL SHOWERS AND
THUNDERSTORMS...SOME WITH HEAVY RAINFALL...WILL OCCUR TONIGHT INTO
TOMORROW. DRIER AND LESS HUMID CONDITIONS WILL RETURN FOR THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM EDT...RADARS INDICATING STILL NO REAL CONVECTION HAS
DEVELOPED OVER THE AREA. THERE WERE PLENTY OF CU AND SOME HIGH
CLOUDS AND MSAS ANALYSIS INDICATED SURFACE BASED CAPES UP TO 1500
J/KG.
THE LATEST HRRR AND HIRES WRF MODELS CONTINUE TO INDICATE CONVECTION
WILL DEVELOP DURING THE AFTERNOON.
FORCING REMAINS WEAK BUT ANY WEAK BOUNDARIES INCLUDING A DEWPOINT
BOUNDARY WELL TO OUR WEST IN SW NY...AND EVEN TERRAIN ASPECT COULD
ALLOW FOR SOME CONVECTION TO DEVELOP LATER IN THE AFTERNOON. THERE
ARE BREAKS OF SUNSHINE...ALBEIT NOT MANY...THAT COULD HELP THE
CAUSE.
FOR THIS UPDATE...PUSHED BACK THE TIME OF DEVELOPMENT (LATER) AND
LOWERED POPS A TAD...GENERALLY HELD TO THE 30-50 PERCENT FOR LATE
AFTERNOON. THE 12Z ALY/MODEL SOUNDINGS DO INDICATE A DISTINCT MID
LEVEL DRY AREA THAT COULD ALLOW FOR MOMENTUM OF MODEST WINDS ALOFT
TO MIX DOWN...ALTHOUGH THEY ARE ONLY AROUND 40 KTS AROUND THE
20,000+ LEVEL. WILL LEAVE THEM IN
KEPT HIGH TEMPERATURES VERY SIMILAR TO BEFORE DESPITE THE FACT THAT
SOME AREAS WERE ALREADY APPROACHING HIGH TEMPERATURES. THE CLOUDS
SHOULD KEEP HIGH TEMPERATURES FROM RISING MUCH MORE. LOOK FOR HIGHS
WITHIN A FEW DEGREES OF 80. HOWEVER DEWPOINTS 65 TO 70 WILL ACTUALLY
MAKE THESE READINGS FEEL A TAD HIGHER.
SOME OF THE MORE SPECIFIC PARAMETERS AFFECTING CONVECTIVE MODE
THIS AFTERNOON AND EVENING ARE DESCRIBED IN THE PREVIOUS AFD
BELOW...
WITH SFC CAPE VALUES EXPECTED TO REACH AROUND 1000 J/KG...AND 500
HPA WINDS OF AROUND 25-30 KTS IN PLACE...THERE MAY BE JUST ENOUGH
INGREDIENTS IN PLACE FOR A FEW STRONG STORMS ACROSS OUR AREA.
WHILE WIDESPREAD SVR STORMS IS NOT ANTICIPATED...IT/S POSSIBLE
THAT A ROGUE STORM OR TWO COULD PRODUCE GUSTY WINDS...ESP
CONSIDERING INCREASING HIGH PWAT VALUES AROUND 1.50 INCHES
MAY ALLOW FOR A PRECIP LOADING INDUCED WIND GUST WITHIN ANY HEAVY
SHOWER OR THUNDERSTORM. SPC HAS PLACED OUR AREA IN A 5% PROB FOR SVR
WX...AND THIS LOOKS TO BE RIGHT. WE WILL MENTION THE POTENTIAL FOR
GUSTY WINDS IN THE ZONES AND HWO PRODUCT.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
THE SFC FRONT WILL STALL CLOSE TO OR OVER OUR AREA TONIGHT INTO
FRIDAY WHILE THE UPPER LEVEL ENERGY SLOWLY BARRELS ACROSS ONTARIO.
A STRONG JET STREAK AT 250 HPA OF AROUND 125 KTS WILL UNDERCUT THE
UPPER LEVEL LOW AND BE SITUATED OVER THE UPPER GREAT LAKES AND
SOUTHERN CANADA. WITH THE UPSTREAM JET STREAK...HIGH MOISTURE IN
PLACE...AND PROXIMITY OF THE SFC BOUNDARY...SHOWERS AND
THUNDERSTORMS LOOK LIKELY TONIGHT INTO FRIDAY OVER MUCH OF THE
REGION. A WEAK SURFACE WAVE MAY DEVELOP ALONG THE BOUNDARY FOR
FRIDAY AS WELL...WHICH MAY HELP INCREASE COVERAGE OF
SHOWERS/STORMS...AS WELL AS HELP MOVE THE BOUNDARY SOUTHEAST
SOMEWHAT BY LATE IN THE DAY FRIDAY.
IT WILL BE DIFFICULT TO SAY EXACTLY WHERE AND WHEN
SHOWERS/TSTMS WILL TRACK THROUGH THE PERIOD. WITH THE CONVECTIVE
NATURE OF THE PRECIP...THERE IS THE POTENTIAL FOR QPF AMOUNTS TO
BE RATHER VARIABLE ACROSS THE REGION. HOWEVER WE CAN SAY WITH
CERTAINTY THAT WITH PWATS STILL AROUND TWO INCHES...HEAVY RAINFALL
WILL BE A POSSIBILITY WITH ANY SHOWER/STORM...AND WE WILL CONTINUE
TO MENTION THIS IN BOTH THE GRIDS AND HWO. SEE OUR HYDRO SECTION
ON HOW WE EXPECT THIS RAINFALL TO IMPACT THE HSA.
SIMILAR TO TODAY /THURS/...SPC HAS OUR REGION IN A /SEE TEXT/ FOR
STORMS ON FRIDAY WITH A 5% PROB FOR SVR IN PLACE. AGAIN...LIMITED
INSTABILITY AND WEAK LAPSE RATES WILL PREVENT WIDESPREAD SVR
WX...BUT ANY BREAKS IN THE CLOUDS WILL INCREASE THE THREAT FOR A
ROGUE STRONGER STORM.
MIN TEMPS TONIGHT WILL BE WARM AND MUGGY...WITH MID 60S TO LOW 70S
EXPECTED. MAX TEMPS ON FRIDAY WILL GENERALLY BE IN THE 70S TO NEAR
80.
THE FRONT WILL FINALLY START TO MOVE AWAY ON FRIDAY NIGHT. SOME
SHOWERS MAY LINGER ACROSS SOUTHEASTERN AREAS INTO FRIDAY
EVENING...BUT THE ENTIRE REGION SHOULD BE CLEARED OUT BY SAT
MORNING. MIN TEMPS ON FRI NIGHT WILL STILL BE IN THE 60S IN MOST
PLACES.
DRIER AND LESS HUMID CONDITIONS ARE EXPECTED SAT INTO SAT NIGHT AS
SFC HIGH PRESSURE BUILDS INTO THE REGION FROM THE GREAT LAKES. MAX
TEMPS ON SAT WILL BE IN THE 70S TO LOW 80S AND MIN TEMPS SAT NIGHT
WITH BE IN THE 40S AND 50S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MAINLY DRY WEATHER IS EXPECTED DURING THE LONG TERM PERIOD WITH ONLY
A CHANCE OF SHOWERS AND THUNDERSTORMS ON TUESDAY.
SUNDAY THROUGH MONDAY NIGHT...EXPECT DRY CONDITIONS AS A RIDGE OF
HIGH PRESSURE BUILDS ACROSS THE REGION AT THE SURFACE. EXPECT HIGHS
ON SUNDAY AND MONDAY TO RANGE FROM THE LOWER 70S NORTHWEST TO THE
LOWER 80S SOUTHEAST. LOWS SATURDAY NIGHT ARE EXPECTED TO RANGE FROM
THE LOWER 40S NORTHWEST TO MID 50S SOUTHEAST WITH LOWS SUNDAY NIGHT
RANGING FROM THE UPPER 40S NORTHWEST TO UPPER 50S SOUTHEAST AND LOWS
MONDAY NIGHT IN THE 50S TO LOWER 60S.
TUESDAY...A WEAK TROUGH OF LOW PRESSURE WILL SLIDE SOUTHEAST FROM
THE EASTERN GREAT LAKES AND SOUTHEAST CANADA. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED ALONG AND AHEAD OF THIS FEATURE WITH SB
CAPES RISING TO BTWN 500 AND 1000 J/KG HIGHS ON TUESDAY ARE EXPECTED
TO BE IN THE 70S TO AROUND 80 WITH A FEW AREAS ACROSS THE SRN
ADIRONDACKS IN THE UPPER 60S.
TUESDAY NIGHT AND WEDNESDAY...EXPECT A RETURN TO DRY CONDITIONS AS
HIGH PRESSURE BUILDS BACK INTO THE NORTHEAST. LOWS TUESDAY NIGHT ARE
EXPECTED TO RANGE FROM THE UPPER 40S NORTHWEST TO UPPER 50S
SOUTHEAST WITH HIGHS ON WEDNESDAY RANGING FROM THE UPPER 60S
NORTHWEST TO UPPER 70S SOUTHEAST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
EARLY THIS MORNING EXPECT MAINLY VFR VSBYS AND VFR/MVFR CIGS WHICH
WILL GIVE WAY TO ENTIRELY VFR CONDITIONS AFT 14Z. HAVE PLACED VCSH
IN THE TAFS AFT 14Z AS CONVECTION TO THE WEST MOVES EAST INTO THE
HUDSON VALLEY. THE BIG QUESTION WILL BE HOW MUCH OF THIS PCPN HOLDS
TOGETHER AS IT MOVES INTO A SLIGHTLY MORE STABLE AIRMASS. THIS
AFTERNOON THROUGH THIS EVENING LOOKS TO HAVE A BETTER CHANCE OF
CONVECTION AND MORE WIDESPREAD SHOWER ACTIVITY IS EXPECTED LATE
TONIGHT AFT 09Z WITH MAINLY MVFR CONDITIONS.
WINDS SHOULD BE SOUTH TO SOUTHWEST AT 6-10 KTS WITH GUSTS TO 16 KTS
AT KALB. WINDS WILL DIMINISH TONIGHT TO LESS THAN 6 KTS EXCEPT AT
KALB WHERE SOUTH WINDS WILL REMAIN AT 8-10 KTS.
OUTLOOK...
THURSDAY NIGHT AND FRIDAY: HIGH OPERATIONAL IMPACT. LIKELY
SHRA...TSRA.
SATURDAY THROUGH MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WX ISSUES ARE ANTICIPATED OVER THE NEXT SEVERAL DAYS.
SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY
THROUGH TOMORROW NIGHT. DRY WEATHER WILL RETURN OVER THE WEEKEND.
RH VALUES WILL ONLY DROP TO 65 PERCENT THIS AFTERNOON WITH
SOUTHERLY WINDS OF 5 TO 10 MPH. RH VALUES WILL RETURN TO NEAR 100
PERCENT TONIGHT WITH SOUTH WINDS AT 5 MPH. RH VALUES GENERALLY
GREATER THAN 70 PERCENT WILL BE IN PLACE FOR TOMORROW WITH RAIN
SHOWERS LIKELY.
&&
.HYDROLOGY...
SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE REGION TODAY
THROUGH TOMORROW NIGHT AS A COLD FRONT MOVES ACROSS THE REGION.
THE MOST LIKELY PERIOD FOR SEEING RAINFALL WILL BE TONIGHT INTO
FRIDAY. AREAS SOUTH AND EAST OF THE CAPITAL REGION LOOK
TO SEE THE HEAVIEST RAINFALL...AS THE FRONTAL BOUNDARY WILL STALL
CLOSE TO THIS AREA...AND A WAVE OF LOW PRESSURE WILL MOVE ALONG
THE BOUNDARY.
WITH PWATS NEAR TWO INCHES AND DEWPOINTS IN THE MID 60S TO NEAR
70...HEAVY RAINFALL WILL BE POSSIBLE WITHIN ANY OF THE SHOWERS AND
THUNDERSTORMS. FFG VALUES LOOK TO BE AT TYPICAL VALUES FOR EARLY
AUGUST...AND IT WILL REQUIRE ABOUT TWO TO THREE INCHES OF RAINFALL
IN A ONE HOUR PERIOD TO CAUSE FLASH FLOODING. DEPENDING ON WHERE
SHOWERS AND THUNDERSTORMS TRACK...MINOR FLOODING OF URBAN...POOR
DRAINAGE...AND LOW LYING AREAS WILL BE POSSIBLE THROUGH
FRIDAY...MAINLY FOR AREAS SOUTH AND EAST OF THE CAPITAL REGION.
DRIER WEATHER WILL RETURN TO THE REGION OVER THE WEEKEND. WHILE
THERE MAY BE SOME IN BANKS RISES ON MAIN STEM RIVERS AND STREAMS LATE
THIS WEEK...DRY WEATHER OVER THE WEEKEND WILL ALLOW THESE FLOWS TO
RECEDE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/NAS
NEAR TERM...HWJIV/NAS/FRUGIS
SHORT TERM...FRUGIS
LONG TERM...11
AVIATION...11
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
117 PM EDT THU AUG 8 2013
.SYNOPSIS...
LOW PRESSURE MOVING ACROSS SOUTHEASTERN CANADA WILL ALLOW A COLD
FRONT TO APPROACH THE REGION ON FRIDAY AND CROSS THE AREA BY LATE
FRIDAY OR EARLY SATURDAY. THIS FRONT WILL EVENTUALLY STALL TO OUR
SOUTH FOR SUNDAY. EARLY NEXT WEEK, A FEW WAVES OF LOW PRESSURE ARE
FORECAST TO MOVE ALONG THE STALLED BOUNDARY. HIGH PRESSURE WILL
THEN BUILD IN TOWARD MIDWEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NOT A CONFIDENT ESTF UPDATE. WE HAVE DECIDED TO COMPROMISE BETWEEN
PREVIOUS FCST AND CURRENT SUGGESTIONS BY THE HRRR AND COSPA. WE
ARE SEEING A SHORT WAVE EMERGE FROM WV AND COUPLED WITH CONVECTIVE
TEMPERATURES BEING REACHED BELIEVE THIS SHOULD START TRIGGERING
AND ENHANCING CONVECTION AS WE MOVE FORWARD. THE PREVIOUS MCS HAS
LEFT A RELATIVELY STABLE POOL NW OF OUR CWA FOR NOW. SO THE
ADJUSTMENTS GOING FORWARD WERE TO LOWER POPS INITIALLY NORTHWEST
AND GIVE THAT SHORT WAVE A BIT MORE CREDIT AND INCREASE POPS IN
THE CENTRAL THIRD OF OUR CWA FOR THIS AFTERNOON. WE DID SEE A
NOTICEABLE DROP OFF IN 925MB OR 850MB MOISTURE OFF THE WALLOPS
SOUNDING THIS MORNING, SO CHANCES WERE KEPT IN THE SERN PART OF
OUR CWA. WE ARE WARMING AT 700MB AND 500MB, SO WITH BULK SHEAR
VALUES BEST NORTH AS WELL AS FORECAST TT(S), WE KEPT THE SOMEWHAT
ENHANCED WORDING TIED TO LIKELY POPS. THE FCST DCAPES ARE NOT
IMPRESSIVE AND NEITHER ARE THETA E DROP WITH HEIGHT, SO ANY STRONG
TO SEVERE ARE GOING TO HAVE TO BE TIED TO SOME RELATIVELY STRONGER
UPDRAFTS OR IF AN EFFECTIVE COOL POOL CAN FORM. THE LATTER DOES
NOT LOOK PROMISING. WE HAVE NOT HAD MANY DRY STRETCHES THIS
SUMMER, BUT THE RELATIVE LACK OF FLOODING RAINS LAST SEVERAL DAYS
HAS PERMITTED FFG AND FFH GUIDANCE TO GET CLOSER TO NORMAL SUMMER
VALUES. SO WHILE A FFW MIGHT STILL OCCUR, THIS WOULD SEEM TO BE
MORE OF AN ISOLATED OCCURRENCE.
12Z SOUNDINGS GIVE 90F AS A POSSIBLE HIGH SOUTHERN PART OF OUR
CWA (CONVECTIVE TEMP LOW 80S), SO BUMPED MAX TEMPS UPWARD IN
DELMARVA, KEPT THE REST RELATIVELY THE SAME.
UPPER HEIGHTS WILL BE RISING THRU THE DAY AND THERE ARE ONLY WEAK
S/W MOVING THRU THE FLOW. BREAKS WILL OCCUR TODAY ALLOWING FOR
POCKETS OF HEATING/INSTABILITY TO DEVELOP. WE WILL GO ALONG WITH THE
DETERMINISTIC MODELS AND MOS AND MOSTLY KEEP THE HIGHER CHC FOR POPS
NORTH MOSTLY THIS AFTERNOON WITH SLGT CHC OR LOW CHC POPS
SOUTH/EAST. THERE WILL BE SOME CAPE VALUES AROUND 750-1250 J/KG
ACROSS THE AREA...BUT THE HIGHEST VALUES WILL OCCUR WITH ANY
BREAKS IN THE CLOUDS TODAY. SPC HAS OUR AREA IN `SEE TEXT` AND
MENTIONS ONLY SMALL POSSIBILITY OF SOME STRONGER WIND GUSTS WITH
ANY CONVECTION THAT DEVELOPS. QPF BASIN AVERAGES...1/2 INCH NORTH
RANGING DOWN TO LIGHT AMTS SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/...
WE WILL CONTINUE IN THE WARM SECTOR TONIGHT WITH THE UPPER FLOW
BECOMING A BIT MORE SWRLY ALOFT. A COLD FRONT WILL BE SLOWING ITS
APPROACH INTO WRN NY AND WRN PA. SHOWERS AND SCT THUNDERSTORMS WILL
CONTINUE FROM THE LATE AFTERNOON INTO THE EARLY OVERNIGHT PERIODS.
THE AREAS NORTH/WEST WILL HAVE THE BETTER CHCS FOR THE RAINS. WE
WILL CARRY THE LIKELY POPS INTO THE OVERNIGHT NORTH/WEST AND HOLD
THE HIGHER CHC POPS SOUTH/EAST. QPF...1/2 INCH NORTH 1/10 INCH
SOUTH.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AN AREA OF LOW PRESSURE IN SERN CANAD WILL WORK ITS WAY EWD. AS IT
DOES A CDFNT WILL CROSS THE AREA FROM W TO E ON FRI INTO FRI
NIGHT. THE LATEST MDL GUID CURRENTLY INDICATES THAT THE FRI
DAYTIME PD COULD BE FAIRLY WET, FOR AT LEAST A PORTION OF THE
AREA, AND THERE COULD BE LOCALIZED CONVECTION WHICH COULD MAKE FOR
PDS OF HEAVY RAIN. IT IS PSBL, IF THE MDLS CONTINUE TO AGREE ON A
LOCATION AS THEY ARE NOW (N AND W) THAT A FFA MAY BE NEEDED AS
RNFL AMTS APPEAR TO BE AOA 1 INCH. THE FRONT SHUD CLEAR THE AREA
DURG THE OVERNIGHT HOURS ON FRI AND CLEARING WILL OCCUR FROM N TO
S. PRECIP MAY LINGER ACRS THE DELMARVA INTO ERLY SAT. THE ECMWF
DOES CLEAR THINGS OUT FASTER THAN THE GFS. BOTH MDLS KEEP THE
FRONT CLOSE BY, SO IT WON`T TAKE MUCH IN THE WAY OF A PERTURBATION
FOR IT TO BRING ANOTHER SHOT OF PRECIP, BUT FOR BOTH MDLS DRY
THINGS OUT BY LATER SAT AT THE LATEST, AS HIGH PRESSURE BUILDS IN.
SUN THEN LOOKS DRY. MUCH LESS CONFIDENCE INTO MON AS THE GFS WANTS
TO BRING A WAVE ACRS THE STALLED FRONT, WHICH WOULD BRING PRECIP,
MAINLY ACRS THE S. THE ECMWF IS DRY DURG THIS TIME. THE CMC ALSO
HAS A WAVE ON MON, BUT ITS OVERALL SYNOPTIC PATN IS A BUT SUSPECT
OVERALL. BY TUE, THE MDLS BRING ANOTHER LOW TO THE N AND ANOTHER
CDFNT ACRS THE REGION, AND ANOTHER CHC OF RAIN.
THIS IS A LOW CONFIDENCE FCST FOR THE EARLY PORTION OF NEXT WEEK
AS IT WILL BE DEPENDENT ON THE POSN OF THE FRONT AND IF ANY WAVES
DEVELOP ALG IT AND WHERE THEY MOVE. BASED ON THE ECMWF`S GENLY
SUPERIOR PERFORMANCE, WANT TO GIVE IT A BIT OF A NOD, BUT CAN`T
RULE OUT A MORE PESSIMIST SOLN EITHER. FOR NOW, WILL BRING IN LOW
POPS MON, LOW CHC POPS ON TUE TO SEE HOW THINGS PLAY OUT AND THEN
A DRY FCST ON WED AS HIGH PRESSURE BUILDS IN.
TEMPS WILL GENLY BE AT OR SLIGHTLY ABV NRML THRU THE PD.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE 18Z TAF PACKAGE IS NOT THAT OPTIMISTIC WITH A COUPLE OF ROUNDS
OF SHOWERS AND THUNDERSTORMS EXPECTED WITH CONDITIONS GOING BACK
TO PREDOMINATELY MVFR TONIGHT.
FOR THIS AFTERNOON, CIGS SHOULD BECOME OR BE VFR FROM TAF ONSET
TIME FROM THE KPHL AIRPORTS SOUTH AND EAST. NOT AS CONFIDENT ABOUT
NW TERMINALS. WE ARE EXPECTING AN UPPER AIR DISTURBANCE TO
INITIATE SHOWERS AND THUNDERSTORMS AND MOVE ACROSS (OR HAVE THE
POTENTIAL TO) ALL THE TERMINALS LATER THIS AFTERNOON. MVFR
CONDITIONS ARE LIKELY DURING THE CONVECTION. TIMING IS FROM THE
SOUTHWEST TERMINALS TO THE NORTHEAST TERMINALS. SOUTH TO SOUTHWEST
WINDS WILL AVERAGE AROUND 10 KTS,
FOR TONIGHT AS A WHOLE, IT LOOKS AS THOUGH THERE WILL ONE,
POSSIBLY A SECOND WAVE OF CONVECTION. THE INITIAL WAVE TIMING IS
AN ESTIMATE AT THIS POINT AND THERE MIGHT BE A SECOND WAVE TOWARD
MORNING. REGARDLESS OF THE WAVES, WE ARE EXPECTING CIGS AND VSBYS
TO LOWER TO MVFR AGAIN WITH POSSIBLY SOME IFR CONDITIONS
ESPECIALLY NWRN AIRPORTS AND TERMINALS. LIGHTER SOUTH WINDS
EXPECTED.
ON FRIDAY, EVEN MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
EXPECTED. THERE SHOULD BE A QUICKER STARTING TIME ALSO. WHILE NO
THUNDER HAS BEEN PUT INTO THE TAFS, IT IS LIKELY THEY WILL HAVE AN
IMPACT ON THE TERMINALS WHETHER OR NOT THEY DIRECTLY PASS OVER THEM.
SOUTHWEST WINDS WILL AVERAGE AROUND 10 KNOTS.
OUTLOOK...
FRIDAY NIGHT THROUGH EARLY MORNING SATURDAY...MAINLY MVFR OR IFR
CONDITIONS EXPECTED IN SHOWERS AND PSBL TSTMS. SOME HVY RAIN PSBL.
MDT CONFIDENCE.
REMAINDER OF SATURDAY THROUGH MONDAY...MOSTLY VFR CONDITIONS.
ISOLATED SHWRS/TSTMS REMAIN POSSIBLE, ESPECIALLY MON. SUN SHOULD
BE DRY. MDT TO HIGH CONFIDENCE.
&&
.MARINE...
A MODERATE SOUTH WIND CONTINUES ACROSS THE OCEAN WATERS AND MORE OF
A SWLY WIND ACROSS DEL BAY. OVERALL...THE WIND SPEEDS AND SEAS WILL
REMAIN BELOW SCA CRITERIA TODAY AND TONIGHT. A FEW WIND GUSTS TO 25
KTS MAY OCCUR EARLY THIS MORNING AND LATER TONIGHT...BUT THEY WILL
NOT PERSIST. THE MAIN MARINE HAZARD TODAY AND TONIGHT WOULD BE ANY
GUSTY WINDS ASSD WITH TSTMS WHICH WILL BE AROUND EARLY THIS
MORNING...THIS AFTERNOON AND TONIGHT. SEAS...ON THE OCEAN 3-4 FT AND
DEL BAY 1-2 FT (NORTH) AND 2-3FT (SOUTH).
OUTLOOK...
OVERALL, SUB-SCA CONDITIONS ARE EXPECTED FOR OUR AREA WATERS THROUGH
THE BULK OF THE OUTLOOK PERIOD. GUIDANCE IS SHOWING AN INCREASE IN
THE SOUTHERLY TO SOUTHWESTERLY FLOW DURING FRIDAY AHEAD OF AN
APPROACHING CDFNT. THE WIND CUD GUST TO AROUND 20 KTS OR SO AS
WELL DURG THIS TIME. IN ADDITION, WAVEWATCH GUIDANCE ALSO INDICATES
SEAS RISING TO AROUND 5 OR PSBLY 6 FEET FOR OUR COASTAL WATERS
DURING THIS TIMEFRAME. HOWEVER, THIS GUIDANCE TENDS TO RUN A
LITTLE HIGH IN SOUTHERLY FLOW, AND CONFIDENCE IS BELOW AVERAGE. SO
WILL CONTINUE TO MONITOR FOR ANY PSBL FLAGS. SEAS SHOULD THEN
LOWER BEHIND THE CFP INTO THE WEEKEND, AS WINDS SHIFT TO THE NW.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...NIERENBERG
NEAR TERM...GIGI/O`HARA
SHORT TERM...O`HARA
LONG TERM...NIERENBERG
AVIATION...GIGI/NIERENBERG
MARINE...NIERENBERG/O`HARA
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
438 PM EDT THU AUG 8 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 332 PM EDT THU AUG 8 2013
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 08/2100Z TAF UPDATE/...
ISSUED AT 431 PM EDT THU AUG 8 2013
UPDATE...
SCATTERED SHOWERS AND THUNDERSTORMS WILL IMPACT TAF SITES INTO
EARLY EVENING...CAUSING PERIODS OF MVFR/IFR CONDITIONS.
PREVIOUS DISCUSSION...
LOW CONFIDENCE FORECAST...BUT GENERALLY VFR CONDITIONS GIVING WAY
TO MVFR CONDITIONS OVERNIGHT WITH POTENTIAL FOR IFR. SCATTERED
CONVECTION AROUND THROUGH THE PERIOD...ALONG WITH VARIABLE WINDS.
WEAK BOUNDARY WILL REMAIN ACROSS CENTRAL INDIANA THIS AFTERNOON...
MAKING WINDS VARIABLE. SCATTERED CONVECTION WILL PERSIST AROUND
THIS BOUNDARY...BUT AT THE MOMENT IT APPEARS ORGANIZED CONVECTION
WILL REMAIN OUT OF THE AREA. ANY CEILINGS BELOW MVFR SHOULD LIFT
TO VFR BY VALID TIME EXCEPT FOR KLAF WHERE THEY WILL LINGER.
DURING THE NIGHT...THREAT FOR CONVECTION WILL CONTINUE BUT AT THE
MOMENT DO NOT EXPECT WIDESPREAD CONVECTION /ALTHOUGH SOME MODELS
INDICATE THIS POSSIBILITY...BUT ODDS ARE LOW WITHOUT ANY
SIGNIFICANT FORCING NEARBY/. MOIST AIRMASS WILL LEAD TO MVFR
VISIBILITIES/CEILINGS WITH POTENTIAL FOR IFR. THESE SHOULD IMPROVE
ON FRIDAY WITH DRIER AIR WORKING IN AS BOUNDARY SHIFTS FARTHER
SOUTH.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50/TDUD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
332 PM EDT THU AUG 8 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 332 PM EDT THU AUG 8 2013
WEAK DIFFUSE FRONTAL BOUNDARY WILL SAG SOUTH THROUGH THE REGION INTO
FRIDAY AS SEVERAL SURFACE WAVES RIPPLE ALONG THE BOUNDARY. THIS WILL
KEEP SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL INDIANA INTO
FRIDAY...AND OVER SOUTHERN PORTIONS OF THE AREA INTO EARLY SATURDAY
AS THE FRONT MAKES ONLY SLOW PROGRESS SOUTH INTO THE TENNESSEE
VALLEY. HIGH PRESSURE DRIFTING THROUGH THE GREAT LAKES WILL BRING
DRIER AND SLIGHTLY COOLER WEATHER SATURDAY AND SUNDAY. A COLD FRONT
WILL PASS THROUGH THE AREA EARLY NEXT WEEK WITH RAIN...FOLLOWED BY
REINFORCING SHOT OF COOLER AIR BY MIDWEEK AS THE UPPER TROUGH
DEEPENS OVER THE EASTERN U S.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 332 PM EDT THU AUG 8 2013
MESOLOW RESIDES ACROSS NORTHERN COUNTIES WITH THE FRONTAL BOUNDARY
EXTENDING SOUTHWEST INTO EAST CENTRAL ILLINOIS. LINEAR CONVECTION
HAS DEVELOPED ALONG A DIFFUSE FRONT TO THE WEST OF THE INDY
METRO...WITH ADDITIONAL CONVECTION NOW BEGINNING TO DEVELOP IN
VICINITY OF THE BOUNDARY OVER SOUTH CENTRAL ILLINOIS. MUGGY
AFTERNOON IN PROGRESS AS TEMPS HAVE RISEN INTO THE MID 80S OVER ALL
BUT FAR NORTHERN COUNTIES.
COMPLEX AND LOW CONFIDENCE FORECAST FOR THE REST OF THE AFTERNOON
AND TONIGHT AS THE PRESENCE OF THE BOUNDARY SLOWLY SAGGING SOUTH
THROUGH THE FORECAST AREA AND THE APPROACHING REMNANT MCV NEAR KSTL
ARE LIKELY TO BE FACTORS IN CONVECTIVE COVERAGE INTO THE OVERNIGHT.
HRRR HANDLING CURRENT CONVECTIVE COVERAGE REASONABLY WELL AND WAS
USED AS A START FOR THE NEXT SEVERAL HOURS.
CURRENT MESOANALYSIS INDICATES AIRMASS HAS SUFFICIENTLY DESTABILIZED
ALONG AND IMMEDIATELY AHEAD OF THE BOUNDARY. MUCH OF THE CONVECTION
HAS WEAKENED WITHIN THE VICINITY OF THE WELL DEFINED MCV OVER
EASTERN MISSOURI. HOWEVER AS THIS FEATURE CONTINUES TO APPROACH
CENTRAL INDIANA OVER THE NEXT SEVERAL HOURS AND INTERACTS WITH THE
UNSTABLE AND VERY MOIST AIRMASS OVER THE REGION...EXPECT AN INCREASE
IN CONVECTIVE COVERAGE INTO THE EVENING...LIKELY CONTINUING
OVERNIGHT AS THE MCV MOVES THROUGH THE REGION. BOTH THE RAP AND 12Z
GFS HINT AT THE LOW LEVEL JET REESTABLISHING ALONG THE OHIO RIVER
TONIGHT...WITH A LOW LEVEL BAROCLINIC ZONE SETTING UP ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA. THINK ULTIMATELY SHOULD THIS
COME TO PASS...THE HEAVIEST RAINFALL WILL SET UP OVER SOUTHERN
COUNTIES OVERNIGHT AND WILL CARRY HIGHEST POPS IN THESE AREAS.
IMPRESSIVE PRECIP WATER VALUES IN EXCESS OF 2 INCHES COMBINED WITH
STORM MOTIONS UNDER 10KTS AND STEERING CURRENTS PARALLEL TO THE
BOUNDARY ARE SUPPORTIVE OF TORRENTIAL RAINFALL...BACKBUILDING AND
TRAINING ECHOES AND POTENTIAL FOR LOCALIZED FLOODING. WITH 1 HR/3 HR
FLASH FLOOD GUIDANCE VALUES IN EXCESS OF 2 INCHES/2.5-3.5 INCHES AND
UNCERTAINTY IN HOW EXTENSIVE THE PRECIP COVERAGE BECOMES...HAVE NO
PLANS TO ISSUE A FLASH FLOOD WATCH AT THIS TIME.
TEMPS...WARMER MAVMOS LOOKS REASONABLE CONSIDERING HIGH LOW LEVEL
MOISTURE PRESENT OVER THE REGION. NAM APPEARS TO BE ADVECTING DRIER
AIR INTO THE REGION TOO AGGRESSIVELY EARLY FRIDAY AND THIS IS LIKELY
IMPACTING MET GUIDANCE LOWS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
ISSUED AT 332 PM EDT THU AUG 8 2013
FORECAST CHALLENGES REMAIN ON PRECIP CHANCES INTO EARLY SATURDAY AS
THE FRONTAL BOUNDARY MAKES ONLY SLOW PROGRESS SOUTH.
REMNANT MCV AND A WEAK SURFACE WAVE WILL BE SHIFTING EAST OF THE
REGION BY 12Z FRIDAY. FOCUS FOR ADDITIONAL CONVECTIVE DEVELOPMENT
WILL BE SOUTH OF I-70 AS THE BOUNDARY SETTLES OVER SOUTHERN INDIANA
BY FRIDAY AFTERNOON. WILL ONCE AGAIN FOCUS HIGHEST POPS OVER
SOUTHERN COUNTIES WITH LOW CHANCE POPS NORTH OF I-70 AS SLIGHTLY
DRIER AIR BEGINS TO EXPAND SOUTH FROM THE GREAT LAKES. THE BOUNDARY
WILL CONTINUE TO SHIFT SOUTH THROUGH KENTUCKY ON FRIDAY NIGHT AS AN
UPPER LOW PIVOTS SOUTH OF JAMES BAY AND INTRODUCES A BROAD UPPER
LEVEL TROUGH OVER THE EASTERN U S. WILL HANG ONTO LOW CHANCE POPS
OVER SOUTHERN COUNTIES FRIDAY NIGHT AND EARLY SATURDAY DUE TO THE
CLOSE PROXIMITY OF THE BOUNDARY...BUT OVERALL TREND INTO SATURDAY
SHOULD BE TOWARDS DRIER AND SLIGHTLY COOLER AIR EXPANDING INTO THE
FORECAST AREA AS THE DEEPER MOISTURE IS PUSHED SOUTH.
SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOWER GREAT LAKES
SATURDAY AFTERNOON THROUGH SUNDAY WITH DRY WEATHER. LOW LEVEL
MOISTURE ATTEMPTS TO IMMEDIATELY RETURN BACK NORTH INTO THE OHIO
VALLEY SUNDAY AFTERNOON AS THE HIGH SHIFTS AWAY TO THE EAST. HAVE
KEPT DRY CONDITIONS THROUGH 00Z MONDAY AS LITTLE FORCING ALOFT
PRESENT...ALTHOUGH WILL HAVE TO MONITOR FOR ISOLATED SHOWERS OVER
THE LOWER WABASH VALLEY AS INSTABILITY AXIS WILL BE CLOSE BY ACROSS
THE LOWER OHIO VALLEY.
TEMPS...MOS GUIDANCE IN GENERAL WORKS WELL CONSIDERING LOW LEVEL
THERMALS THROUGHOUT THE PERIOD. HIGH TEMPS FRIDAY AND SATURDAY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER...BUT GENERALLY LOOKING AT LOW TO
MID 80S BOTH DAYS...SLIGHTLY COOLER WHERE RAIN/CLOUDS IMPACT. CORE
OF THE COOLER AIR ASSOCIATED WITH THE UPPER TROUGH LIKELY DELAYED TO
SUNDAY AS 850MB TEMPS FALL TO AROUND 11C. LOCATIONS SUNDAY SHOULD
REMAIN IN THE UPPER 70S AND LOWER 80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
&&
.AVIATION /DISCUSSION FOR THE 081800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT THU AUG 8 2013
LOW CONFIDENCE FORECAST...BUT GENERALLY VFR CONDITIONS GIVING WAY TO
MVFR CONDITIONS OVERNIGHT WITH POTENTIAL FOR IFR. SCATTERED
CONVECTION AROUND THROUGH THE PERIOD...ALONG WITH VARIABLE WINDS.
WEAK BOUNDARY WILL REMAIN ACROSS CENTRAL INDIANA THIS
AFTERNOON...MAKING WINDS VARIABLE. SCATTERED CONVECTION WILL PERSIST
AROUND THIS BOUNDARY...BUT AT THE MOMENT IT APPEARS ORGANIZED
CONVECTION WILL REMAIN OUT OF THE AREA. ANY CEILINGS BELOW MVFR
SHOULD LIFT TO VFR BY VALID TIME EXCEPT FOR KLAF WHERE THEY WILL
LINGER.
DURING THE NIGHT THREAT FOR CONVECTION WILL CONTINUE BUT AT THE
MOMENT DO NOT EXPECT WIDESPREAD CONVECTION /ALTHOUGH SOME MODELS
INDICATE THIS POSSIBILITY...BUT ODDS ARE LOW WITHOUT ANY SIGNIFICANT
FORCING NEARBY/. MOIST AIRMASS WILL LEAD TO MVFR
VISIBILITIES/CEILINGS WITH POTENTIAL FOR IFR. THESE SHOULD IMPROVE
ON FRIDAY WITH DRIER AIR WORKING IN AS BOUNDARY SHIFTS FARTHER SOUTH.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
229 PM EDT THU AUG 8 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 210 AM EDT THU AUG 8 2013
WARM AND HUMID AIR WILL REMAIN OVER INDIANA FOR THE NEXT FEW DAYS
AS A FRONTAL BOUNDARY LINGERS ACROSS SOUTHERN INDIANA. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH FRIDAY NIGHT AS
SEVERAL UPPER LEVEL WEATHER DISTURBANCES PUSH INTO THE OHIO VALLEY.
DRY AND LESS HUMID WEATHER WILL ARRIVE SATURDAY AS HIGH PRESSURE
FROM CANADA BUILDS ACROSS THE REGION.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1003 AM EDT THU AUG 8 2013
LOW STRATUS STUBBORNLY HANGING ON ACROSS A GOOD PORTION OF THE
FORECAST AREA...WITH CLOUDS HAVING ACTUALLY INCREASED IN COVERAGE
OVER NORTHERN COUNTIES SINCE 12Z. SCATTERED CONVECTION HAS ALSO
DEVELOPED OVER THE NORTHERN WABASH VALLEY OVER THE LAST HOUR OR
SO. 13Z SURFACE ANALYSIS PLACES THE WEAK REMNANT BOUNDARY ACROSS
THE FORECAST AREA...ROUGHLY EXTENDING FROM NEAR RICHMOND W/SW TO
JUST SOUTH OF THE INDY METRO AND KHUF. MUGGY MORNING WITH TEMPS
MAINLY IN THE 70S.
COMPLEX FORECAST FOR THE REMAINDER OF THE DAY AS CONVECTION HAS
DEVELOPED SOONER THAN ANTICIPATED. VERY WEAK FORCING ALOFT WITHIN
A POORLY DEFINED UPPER TROUGH COMBINED WITH AN AREA OF LOW LEVEL
MOISTURE CONVERGENCE APPEAR TO BE CONTRIBUTING TO THE CONVECTIVE
DEVELOPMENT NORTHWEST OF INDY THIS MORNING. HRRR GUIDANCE IS
CAPTURING THIS TO SOME DEGREE...AND TRENDS TOWARDS FURTHER
CONVECTIVE DEVELOPMENT ACROSS THE FORECAST AREA INTO THE
AFTERNOON. CONSIDERING INCREASING INSTABILITY OVER THE NEXT FEW
HOURS COMBINED WITH THE DEEP LOW LEVEL MOISTURE PRESENT...WEAK
FORCING ALOFT AND THE PRESENCE OF THE BOUNDARY ACROSS THE
REGION...REALLY HARD TO ARGUE WITH THIS SCENARIO AT THIS POINT.
BUMPED UP POPS TO BEGIN NORTHWEST OF INDY NOW...THEN INCREASE TO
30-50 POPS OVER ENTIRE FORECAST AREA FOR THE AFTERNOON. MENTIONING
ONLY ISOLATED THUNDER THROUGH MIDDAY AS MESOANALYSIS SHOWS LITTLE
INSTABILITY PRESENT RIGHT NOW. EXPECT A BETTER CHANCE FOR THUNDER
THIS AFTERNOON AS INSTABILITY INCREASES WITH DIURNAL HEATING.
WHILE THERE ARE BREAKS IN THE CLOUD COVER THIS MORNING...
ESPECIALLY OVER SOUTHERN COUNTIES...HAVE INCREASED CLOUD COVERAGE
FOR THE AFTERNOON AS CU LIKELY TO FILL IN AS CONVECTIVE TEMPS ARE
MET. ADDITIONALLY...CLOUD DEBRIS FROM WEAKENING MCS OVER THE
OZARKS POISED TO EXPAND INTO THE REGION THIS AFTERNOON. WITH THE
INCREASE IN CLOUDS...DROPPED HIGH TEMPS A COUPLE DEGREES AS WELL.
ZONE AND GRID UPDATES OUT SHORTLY.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 210 AM EDT THU AUG 8 2013
LITTLE CHANGE APPEARS IN THE OVERALL PATTERN THROUGH FRIDAY
AFTERNOON. GFS AND NAM CONTINUE TO SUGGEST WEAK...POORLY ORGANIZED
SHORT WAVES PUSHING THROUGH THE FLOW ALOFT. MEANWHILE THE FRONTAL
BOUNDARY LINGERS NEAR THE OHIO VALLEY. 310K GFS ISENTROPIC SURFACE
FAILS TO SHOW MUCH IN THE WAY OF LIFT...BUT DOES MANAGE TO
ILLUSTRATE THE VERY MOIST AIR MASS ACROSS THE AREA SHOWING
SPECIFIC HUMIDITIES IN EXCESS OF 4 G/KG ON FRIDAY. FORECAST
SOUNDINGS THROUGH FRIDAY SHOW LESS FAVORABLE LAPSE RATES WITH
LESS CAPE THAN TODAY. HOWEVER WITH THE MOIST FLOW ALOFT...MOIST
AIR IN PLACE AT THE SURFACE AND UNCERTAINTY REMAINING WITH ANY
EMBEDDED SHORT WAVES WILL CONTINUE TO KEEP LOW CHC POPS TONIGHT
AND AGAIN ON FRIDAY. WILL TREND LOWS WARMER THAN MAVMOS AND STICK
CLOSE ON HIGHS FOR FRIDAY.
ON FRIDAY NIGHT THE GFS AND NAM BOTH SUGGEST A STRONG SHORT WAVE
ALOFT SWEEPING THROUGH THE FLOW. TIME HEIGHT SECTIONS BEGIN TO
SHOW MORE VV WHILE THE NAM SOUNDINGS SHOW DEEP SATURATION. THE GFS
IS MUCH LESS AGGRESSIVE WITH SATURATION...BUT STILL DOES SHOW THE
MAIN WAVE ALOFT. MEANWHILE GFS 310K ISENTROPIC SURFACE SHOWS
MINIMAL LIFT...BUT A VERY MOIST AIR MASS IN PLACE WITH SPECIFIC
HUMIDITIES OVER 5 G/KG AGAIN. IN THE LOWER LEVELS...BEST
CONVERGENCE REMAINS NEAR THE FRONT...LINGERING NEAR THE OHIO
RIVER. THUS WILL USE A BLEND OF THE LOW GFS POPS AND THE HIGHER
NAM POPS FOR FRIDAY NIGHT.
A MUCH DIFFERENT AIR MASS ARRIVES ON SATURDAY AND SATURDAY NIGHT
AS HIGH PRESSURE BUILDS ACROSS THE AREA FROM CANADA. FORECAST
SOUNDINGS AGREE AS THE COLUMN DRIES OUT DRAMATICALLY AMID
SUBSIDENCE. CONVECTIVE TEMPERATURES LOOK QUITE REACHABLE WITH A
MID LEVEL CAP IN PLACE...THUS EXPECTED SOME AFTERNOON CU ON
SATURDAY AND MOSTLY CLEAR SKIES THAT NIGHT. GIVEN THE FORECAST
SOUNDINGS WILL TREND HIGHS ON SATURDAY COOLER THAN MAVMOS AND
STICK CLOSE ON LOWS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 229 PM EDT THU AUG 8 2013
MODELS ARE SIMILAR ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
USED FOR MOST ITEMS IN THE LONG TERM.
UPPER TROUGH WILL DEEPEN ACROSS THE AREA IN THE EXTENDED. THIS WILL
KEEP CENTRAL INDIANA IN COOLER NORTHWEST FLOW. TEMPERATURES WILL
REMAIN BELOW AVERAGE THROUGH THE PERIOD.
A COLD FRONT WILL WORK ITS WAY SOUTH MONDAY INTO TUESDAY BRINGING
THE COOLER AIR TO THE AREA. MODELS AND SOME ENSEMBLES ARE SHOWING
CHANCES FOR RAIN LINGERING INTO TUESDAY WITH SOME TIMING DIFFERENCES
BETWEEN THEM. GIVEN THE UNCERTAINTIES INVOLVED WILL GO WITH
ALLBLEND/S CHANCES FOR RAIN MONDAY INTO TUESDAY...BUT AT THE MOMENT
FEEL THAT BEST CHANCES WILL BE LATER ON MONDAY INTO MONDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR THE 081800Z TAF ISSUANCE/...
ISSUED AT 100 PM EDT THU AUG 8 2013
LOW CONFIDENCE FORECAST...BUT GENERALLY VFR CONDITIONS GIVING WAY TO
MVFR CONDITIONS OVERNIGHT WITH POTENTIAL FOR IFR. SCATTERED
CONVECTION AROUND THROUGH THE PERIOD...ALONG WITH VARIABLE WINDS.
WEAK BOUNDARY WILL REMAIN ACROSS CENTRAL INDIANA THIS
AFTERNOON...MAKING WINDS VARIABLE. SCATTERED CONVECTION WILL PERSIST
AROUND THIS BOUNDARY...BUT AT THE MOMENT IT APPEARS ORGANIZED
CONVECTION WILL REMAIN OUT OF THE AREA. ANY CEILINGS BELOW MVFR
SHOULD LIFT TO VFR BY VALID TIME EXCEPT FOR KLAF WHERE THEY WILL
LINGER.
DURING THE NIGHT THREAT FOR CONVECTION WILL CONTINUE BUT AT THE
MOMENT DO NOT EXPECT WIDESPREAD CONVECTION /ALTHOUGH SOME MODELS
INDICATE THIS POSSIBILITY...BUT ODDS ARE LOW WITHOUT ANY SIGNIFICANT
FORCING NEARBY/. MOIST AIRMASS WILL LEAD TO MVFR
VISIBILITIES/CEILINGS WITH POTENTIAL FOR IFR. THESE SHOULD IMPROVE
ON FRIDAY WITH DRIER AIR WORKING IN AS BOUNDARY SHIFTS FARTHER SOUTH.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...RYAN
SHORT TERM...PUMA
LONG TERM....50
AVIATION...50
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AREA FORECAST DISCUSSION
NWS WICHITA KS
108 PM CDT THU AUG 8 2013
.UPDATE...
ISSUED AT 102 PM CDT THU AUG 8 2013
MCV OVER EASTERN KS WAS NOT WELL HANDLED BY OVERNIGHT GUIDANCE AND
ONLY MARGINALLY WELL BY 1200 UTC RUNS. RADAR/SATELLITE TRENDS SHOW
PRECIPITATION ON THE WANE. BEST CHANCES LIKELY WILL BE IN SOUTHEAST
KS WHERE DEEPER MOISTURE/BETTER INSOLATION AND INSTABILITY MAY BE
SUFFICIENT TO BREAK CAP LATE THIS AFTERNOON/EVENING. ANTICIPATING
PRECIPITATION TO WANE THIS EVENING AND MUCH OF THE NIGHT...BUT
SIMILAR TO THIS MORNING...BELIEVE PRECIPITATION WILL DEVELOP AND
MOVE INTO SOUTH CENTRAL/SOUTHEAST KS JUST PRIOR TO DAYBREAK. EARLY
LOOK APPEARS TO SUGGEST THAT PRECIPITATION MAY NOT BE AS HEAVY AS
PREVIOUS DAYS. TEMPERATURES THIS AFTERNOON WILL LIKELY REBOUND
WITH SOME BREAKS IN CLOUDS IN SOUTHEAST KS. -HOWERTON
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
TODAY & TONIGHT:
AS ALL OBVIOUSLY KNOW...FLOODING TO CONTINUE BEINGING THE HIGHLIGHT OF
FOR PERIODS AS FLOOD WATCH REMAINS IN EFFECT TIL 7 AM FRIDAY.
DURING THE NIGHT A POORLY-DEFINED STATIONARY FRONT WAS DRAPED IN AN E-W
MANNER GENERALLY THROUGH CNTRL OK WITH A WEAK 700-MB TROF SITUATED FROM
THE UT/CO BORDER TO ~CA/AZ BORDER. WITH THE TROF SLOWLY EVOLVING INTO A
WEAK LOW AS IT VENTURES E TO WRN KS RICH & DEEP MOISTURE WILL CONTINUE
TO SPREAD NE ACROSS KS. WITH THE MID-LVL "KICKER" LACKING THE SFC-850MB
FRONTS WILL MOVE VERY LITTLE...IF AT ALL...THEREBY PROMOTING BROAD ECHO
TRAINING OVER KICT COUNTRY WHICH IN TURN WOULD EXACERBATE THE FLOODING
SITUATION ACROSS THE CWA. ONLY CHANGES TO INHERITED FORECAST WERE TO
SHIFT THE POP GRADIENT TO GENERALLY A N/S ORIENTATION TO BETTER ALIGN
WITH THE BROAD LWR-MID DECK MOISTURE CHANNEL. ASSIGNED 80-100% TO CNTRL
& SC KS THIS MORNING WITH HIGHEST POPS & ASSOCIATED TSRA SHIFTED E OVER
SE KS THIS AFTERNOON AS HRRR DEPICTS. PW`S REMAIN IN 175-200% RANGE SO
CONTINUED TO HIT QPFS HARD.
FRI & FRI NIGHT:
A FAIRLY BROAD UPR-DECK RIDGE IS FORECAST MOVE SLOWLY MOVG E TOWARD THE
CNTRL ROCKIES...THE WEAK MID-LVL LOW WILL GET FORCED E TOWARD...THEN
ACROSS...ERN KS. THIS WOULD THEREFORE SHIFT BULK OF +TSRA E ACROSS THE
KS/MO BORDER ON FRI WITH -TSRA CONFINED FROM GENERALLY THE FLINT HILLS
E FRI NGT. AS SUCH WILL CONTINUE TO SCHEDULE THE FLOOD WATCH TO END AT
7AM FRI.
SAT & SAT NGT:
MOST AREAS WILL EXPERIENCE AN INTERMISSION FROM TSRA. A FEW TSRA SHOULD
VENTURE TOWARD THE WRN CORRIDOR SAT NGT AS WEAK LWR-DECK TROFFING
BEGINS ALONG THE FRONT RANGE.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 328 AM CDT THU AUG 8 2013
ALL AREAS TO BE UNDER A WEAK NW FLOW REGIME FOR MOST OF THESE PERIODS.
A WEAK COLD FRONT WILL VENTURE SE TOWARD & PERHAPS ACROSS KICGT COUNTRY
EARLY NEXT WEEK WHICH WOULD INCREASE TSRA CHANCES FOR MUCH OF THESE
PERIODS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 102 PM CDT THU AUG 8 2013
ANTICIPATE VFR CONDITIONS THIS AFTERNOON...ALTHOUGH A FEW SITES MAY
BRIEFLY HAVE MVFR CEILINGS AT THE ONSET. ISOLATED/SCATTERED
THUNDERSTORMS POSSIBLE AT KCNU/SE KS LATER THIS AFTERNOON/EVENING
DRIVEN BY AFTERNOON HEATING AND DEEP LOW LEVEL MOISTURE. BETTER
CHANCES OF PRECIPTATION WILL OCCUR CLOSER TO DAYBREAK AT
KHUT/KICT/KCNU AS NEXT IN SERIES OF UPPER SHORTWAVES MOVE THROUGH
THE AREA. -HOWERTON
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 68 79 65 83 / 50 40 10 10
HUTCHINSON 65 76 63 82 / 40 40 10 10
NEWTON 66 76 63 81 / 40 50 10 10
ELDORADO 67 79 64 82 / 50 50 20 10
WINFIELD-KWLD 70 82 66 84 / 60 30 10 10
RUSSELL 63 76 62 82 / 20 40 10 10
GREAT BEND 63 75 61 81 / 30 40 10 10
SALINA 65 77 63 83 / 30 50 10 10
MCPHERSON 65 76 63 82 / 30 50 10 10
COFFEYVILLE 71 86 68 84 / 80 40 20 10
CHANUTE 69 81 66 82 / 70 60 20 10
IOLA 68 80 66 81 / 60 70 20 10
PARSONS-KPPF 70 84 67 83 / 80 50 20 10
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY MORNING FOR KSZ032-033-047>053-
067>072-082-083-091>096-098>100.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1159 AM MDT THU AUG 8 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 446 AM MDT THU AUG 8 2013
FORECAST CONCERNS WILL BE THREAT OF HEAVY RAINFALL AND CHANCES OF
PRECIPITATION. SATELLITE SHOWING LITTLE CHANGE AS A COMPLEX AND
AMPLIFIED PATTERN FROM THE CENTRAL PACIFIC INTO NORTH AMERICA
REMAINS IN PLACE. COMPLEX AND SLOW MOVING UPPER HAS MOVED INTO
COLORADO AND NEW MEXICO. SEVERAL SHORTWAVE TROUGHS ROTATING AROUND
THIS MAIN SYSTEM. AIR MASS REMAINS MOIST THROUGH A DEEP LAYER.
PERSISTENT FRONTAL BOUNDARY REMAINS DRAPED TO OUR SOUTH AND WEST.
AT JET LEVEL...THE CANADIAN AND THE UKMET INITIALIZED BEST ON THE
JET THAT IS OVER/NEAR OUR AREA. AT MID LEVELS...SATELLITE AND UPPER
AIR ANALYSIS SHOW THAT THE ECMWF/CANADIAN FOLLOWED BY THE GFS ARE
HANDLING CURRENT SYSTEM THE BEST. SREF AND RUC WERE DOING BEST AT
THE SURFACE.
COMPLICATED AND DIFFICULT PRECIPITATION FORECAST MADE MORE DIFFICULT
BY THE FACT THAT MOST IF NOT ALL THE MODEL OUTPUT HAS CURRENT
PRECIPITATION SHIELD TOO FAR SOUTH AND IS BASICALLY IGNORING IT.
TODAY/TONIGHT...WEAK RIGHT REAR QUADRANT OF THE UPPER JET REMAINS
OVER THE AREA FOR MOST OF THE DAY. MODELS ARE IN A LITTLE MORE
DISAGREEMENT ON HOW FAST TO MOVE THIS SEGMENT EAST. ALTHOUGH THE
GENERAL TREND IS TO HAVE THIS SLOWER/FURTHER WEST THAN THE PREVIOUS
TWO DAYS. THE SLOWEST OF THE MODELS DO NOT TAKE THIS RIGHT REAR
QUADRANT TO THE EAST OF THE FORECAST AREA UNTIL BETWEEN 06Z AND 12Z.
BASED ON CURRENT SATELLITE...LATEST ECMWF IS CATCHING THE POSITION
AND COMPLEXITY OF THE UPPER TROUGH THE BEST. CONSIDERING THE
POSITION OF THE 700 MB LOW CIRCULATION...MODELS INDICATING WARM
ADVECTION/UPGLIDE IN ADVANCE OF IT...PLUS STRONG UPPER DIVERGENCE
INDICATED THE EASTERN PORTION OF THE AREA...BELIEVE THE CURRENT
PRECIPITATION WILL CONTINUE TO MOVE AND DEVELOP AND MAINLY AFFECT
THE EASTERN THIRD TO HALF OF THE FORECAST AREA.
THIS LOOKS TO BE THE BEST AREA FOR MODERATE TO HEAVY RAINFALL TO
CONTINUE THROUGH AT LEAST THIS AFTERNOON. GREELEY AND WALLACE
COUNTIES APPEAR TO BE ON THE EDGE THIS AREA AT THIS TIME. HOWEVER...
BOTH OF THOSE COUNTIES...ESPECIALLY WALLACE...GOT AT LEAST 2 TO 5
INCHES OF RAINFALL LAST. SO BELIEVE CHEYENNE COUNTY COLORADO DID
NOT RECEIVE A LOT OF HEAVY RAINFALL AND DO NOT EXPECT IT TODAY...
REMOVED THEM FROM THE FLASH FLOOD WATCH. KEPT THE REMAINDER IN THE
WATCH AND EXTENDED IT THROUGH THE AFTERNOON HOURS DUE TO THE SLOW
PROGRESSION OF THE SYSTEM ACROSS THE AREA.
QUESTION THEN BECOMES HOW FAR WEST TO BRING THE PRECIPITATION. THE
ECMWF IS SHOWING WRAP AROUND PRECIPITATION AND THE HRRR INDICATING
THE SAME IDEA. VERY INTERESTING OCCURRENCE FOR THIS TIME OF YEAR.
CURRENT RADAR TRENDS WOULD INDICATE THIS IS TAKING PLACE. SO KEPT
HIGHER POPS FURTHER WEST AS A RESULT. OVERALL...IF THE ECMWF IS RIGHT
AND IT IS SUPPORTED BY THE GEFS...THIS RAINFALL...EVEN AFTER THE
INTENSITY LETS UP...WILL BE SLOW TO END AND WILL PROBABLY NOT DO SO
UNTIL LATE TONIGHT. DID NOT INSERT AT THIS TIME BUT FOG WILL BE
POSSIBLE IF RAIN QUITS SOONER AND CLEARING CAN OCCUR.
LOWERED MAXES TODAY DUE TO CONTINUED PRECIPITATION AND THICK CLOUD
COVER.
FRIDAY/FRIDAY NIGHT...INTEREST PATTERN CONTINUES. THE ECMWF SHOWING
IT MORE BUT ALSO INDICATED BY THE OTHER MODELS AND GEFS OUTPUT...
MID LEVEL TROUGH REMAINS NEAR TO OVER THE AREA WITH WHAT LOOKS TO BE
A DECENT AMOUNT OF MOISTURE LEFT. ALSO A LEFT FRONT QUADRANT OF A
SOUTHERN JET BECOMES ESTABLISHED OVER THE AREA...ESPECIALLY THE
SOUTHEAST HALF...BY THE MIDDLE OF THE DAY. THIS CONTINUES TO AFFECT
THE AREA...ESPECIALLY THE SOUTHERN HALF...THROUGH THE ENTIRE NIGHT.
SO INSERTED POPS WITH THE HIGHEST IN THE SOUTHEAST PORTION. WITH
PERSISTENT CLOUD COVER AND UNFAVORABLE SURFACE WINDS...TRENDED
MAXES DOWN A LITTLE. IF ENOUGH CLEARING CAN OCCUR AND WITH THE MOIST
AIR MASS AND WET GROUND IN PLACE...WOULD NOT BE SURPRISED TO SEE FOG
DEVELOP.
SATURDAY/SATURDAY NIGHT...SOME DIFFERENCE IN THE JET STRUCTURE
THROUGH THE DAY. AS A RESULT IT LOOKS LIKE SOME OR MOST OF THE AREA
COULD GET LIFT FROM THE JET IN THE AREA. MID LEVEL RIDGE MOVES A
LITTLE EAST WITH A SHORTWAVE TROUGH APPROACHING FROM THE WEST IN THE
AFTERNOON. LEE TROUGH STRENGTHENS WITH SOUTHERLY WINDS INCREASING.
POSSIBILITY OF SOME SURFACE CONVERGENCE IN THE FAR WEST. SO PUT IN
A SLIGHT CHANCE IN THE FAR WEST.
ABOVE MENTIONED SHORTWAVE TROUGH AND INCREASING MID LEVEL WARM AIR
ADVECTION PATTERN ALONG WITH INCREASING JET LIFT COULD CAUSE SOME
ISOLATED THUNDERSTORMS OVER THE MOST OF THE AREA. SO PULLED THE
SLIGHT CHANCE FURTHER EAST DURING THE NIGHT.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 446 AM MDT THU AUG 8 2013
UPPER PATTERN THIS PERIOD WILL SLOWLY EVOLVE FROM AN ELONGATED
EAST-WEST UPPER HIGH OVER THE SOUTHERN U.S. TO A HIGH CENTERED OVER
NEW MEXICO AND A SUBSEQUENT GRADUAL BUILDING OF HEIGHTS OVER THE
CENTRAL ROCKIES. MEANWHILE...UPPER LOWS WILL REMAIN ANCHORED OFF
THE PAC NW COAST AND NEAR JAMES BAY...RESULTING IN WEAK TO MODERATE
NORTHWEST FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS. A FEW
WEAK SHORT WAVE TROUGHS WILL LIFT OUT OF THE WEST COAST TROUGH AND
RIDE OVER THE TOP OF THE ROCKIES RIDGE...PROVIDING A FEW
OPPORTUNITIES FOR PRECIP NEXT WEEK AS THEY EMERGE ONTO THE PLAINS.
CURRENT GUIDANCE SUGGESTS THE MON-TUE TIME FRAME WILL PROVIDE
SOMEWHAT BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS...AND THIS IS
INDICATED WITH 30-40 POPS COMPARED TO 20 POPS ON REMAINING DAYS.
NORTHWEST FLOW ALOFT WILL BRING A SURFACE CANADIAN AIRMASS DOWN NEXT
WEEK SUGGESTING HIGH TEMPERATURES WILL REMAIN SEASONAL IN THE 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1159 AM MDT THU AUG 8 2013
SHOWERS AND MVFR CEILINGS SHOULD SLOWLY DIMINISH ACROSS THE TRI-
STATE AREA OVER THE NEXT COUPLE OF HOURS WITH VFR CONDITIONS
TAKING OVER THIS AFTERNOON. SKIES ARE EXPECTED TO GRADUALLY
CLEAR...ESPECIALLY AT KMCK...ALLOWING FOR GOOD RADIATIONAL COOLING
TONIGHT. WITH RECENT RAINFALL AND LIGHT WINDS...FOG AND STRATUS IS
EXPECTED TO DEVELOP WITH IFR TO LIFR CONDITIONS FORECAST. IF SKIES
DO NOT CLEAR OUT TONIGHT...CONDITIONS MAY NOT BE AS BAD DURING THE
OVERNIGHT HOURS. MOST GUIDANCE IS NOT SUGGESTING FOG...HOWEVER IT
SEEMS MODELS ARE HAVING A TOUGH TIME CAPTURING PRESENT WEATHER
CONDITIONS. WINDS ARE EXPECTED TO REMAIN LIGHT THROUGHOUT THE TAF
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH UNTIL 6 PM MDT /7 PM CDT/ THIS EVENING FOR
KSZ027>029-041-042.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DLF
AVIATION...RRH
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1205 PM CDT Thu Aug 8 2013
...Updated for the aviation discussion...
.SYNOPSIS...
ISSUED AT 1010 PM CDT WED AUG 7 2013
The 08.00Z 250 hPa showed 50 KT flow extending from KDDC increasing
to around 100 KT at KAPX. @ 500 hPa, a 577-580 decameter cyclone was
spinning off northwest California. Downstream, an open wave was moving
across the central Rockies. A huge 550 decameter cyclone was noted across
west central Ontario. @ 700 hPa, easterly upslope flow was observed
at KDDC. This upslope flow also continued at 850 hPa and down to the
sfc. The precipitable water for KDDC was 1.41" (above the 75th percentile
for a Gaussian distribution). At the sfc, a stationary front was located
across the KS/OK state border. KDDC WSR-88D was busy indicating an
MCS to the west.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 254 AM CDT THU AUG 8 2013
...Pretty busy shift this morning. Most of the attention was paid to
overnight convection and then some to this afternoon...
This morning:
A fairly significant rain event occurred through the overnight period.
Rainfall reports have been pretty sparse given the fact that it is O`Dark
Thirty. We should get more reports by dawn. A few reports have trickled
in with 3.00" in Hugoton, 1.50" by Richfield, and a few flash flooding
reports. Here at the KDDC airport as of 07:24Z, we have had a measly
half of an inch. Southern Ford county and other areas probably saw 2"
to 4" via estimation from radar. Anyway, given the initial event, canceled
the Flood Watch and issued a Flash Flood Watch instead. So, why all
the precip? Well, an upper level wave, 850 hPa theta-e advection, pwats
around the 75th percentile, sfc-700 hPa upslope flow, and isentropic
lift was the impetus for MCS formation. For the rest of the early morning,
will taper precipitation probability percentage points west to east
via radar trends and HRRR guidance. FWIW, the 00Z NAM performed poorly
for the event.
Will carry the FF.A (Flash Flood Watch) until 18Z.
Today/tonight:
We should see some break in the precipitation from the morning activity
to possible additional activity later this afternoon as temporary subsidence
builds in the wake of the departing MCS. Forecast skew-t/log-p`s show
pwats still in the 1.50-1.70" range this afternoon. A moist upslope
flow will also continue from the sfc up through 800 hPa. The main synoptic
wave mentioned in the synopsis will have translated over western Kansas by
afternoon, and this will provide some upper level support for additional
lift. The atmosphere will become unstable again with 1000-2000 J/kg
of SBCAPE. Low to mid level lapse rates are fairly moist adiabatic,
so the CAPE profile is fairly skinny. Bulk shear vectors are SW/40 KT.
All and all, tomorrow does not look that impressive for severe weather
(supercells etc). What does look more promising is another MCS. There
is significant questions in regarding convective initiation/placement.
The ECMWF and both cores of the WRF look reasonable. The atmosphere
could be "worked over" from the morning convection, so a lack of additional
activity is also possible. Anywho, will carry chance precipitation probabilities
this afternoon and ramp them up to likely region wide by tonight. Maximums
will be in the 70sF and minimums in the 60sF.
.LONG TERM...(Friday through Wednesday)
ISSUED AT 353 AM CDT THU AUG 8 2013
A shortwave trough will move across the central plains reaching
the lower Missouri River Valley by late Friday with shortwave
ridging moving into the western plains. This will provide a break
in precipitation chances from late Friday into Saturday night with
surface ridging across Kansas. Low level moisture will still be
around, however, given all the saturated ground providing ample
evapotranspiration...so dewpoint temperatures will remain int he
60s for the most part despite there being some mid level
subsidence. Some subtropical jet energy will begin to move into
the desert Southwest region impinging on the southern Rockies by
Sunday night into early next week...and this is when precipitation
chances will once again be on the increase. As far as the grids
go...no changes were made to the forecast and the latest all-blend
guidance was used for the Sunday-Thursday time frame.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 1154 AM CDT THU AUG 8 2013
For much of the forecast, expect just scatttered clouds in the 020
range this afternoon, with a scattered to broken deck at 120-150.
As the abundant low level moisture hangs around tonight, and light
easterly upslope winds continue, low stratus in the ovc007 ifr
range will form after 04Z tonight.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 75 63 78 61 / 80 80 20 10
GCK 74 61 77 57 / 70 70 20 10
EHA 77 62 80 60 / 60 60 10 10
LBL 79 63 80 61 / 60 60 20 10
HYS 74 62 76 61 / 90 80 30 10
P28 80 67 81 65 / 80 80 30 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH until 1 PM CDT /Noon MDT/ this afternoon FOR
KSZ030-031-043>046-061>066-074>081-084>090.
&&
$$
SYNOPSIS...SUGDEN
SHORT TERM...SUGDEN
LONG TERM...UMSCHEID
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
649 PM EDT Thu Aug 8 2013
...Forecast Update...
Issued at 648 PM EDT Thu Aug 8 2013
Cluster of light to moderate rain showers continues to trek eastward
across portions of north-central Kentucky. This activity is
expected to continue for the next several hours, but should weaken
as it heads toward the I-75 corridor. More strongly forced
convection is rapidly developing on the southern side of a vorticity
max pushing eastward into Indiana. Storms are forming along a
differential heating and wind shift axis across southern Illinois.
This activity should continue to develop and track eastward along
the I-64 corridor this evening. Latest NAM and HRRR runs suggest
that this would impact north-central Kentucky during the overnight
period. Secondary area of storms is developing over southern MO and
northern AR, this activity will also head east, but may stay just
south of the forecast area late tonight.
With this update, have increased PoPs for the next few hours across
the central portions of the forecast area with the batch of
light-moderate rain moving through. Will continue to ramp up PoPs
tonight as the cluster of storms out to the west heads eastward into
the Ohio Valley.
.SHORT TERM (Now through Friday Night)...
Issued at 315 PM EDT Thu Aug 8 2013
An obstructed blocky flow continues over Canada late today with an
elongated west to east orientated 500mb low over Ontario and Quebec.
Farther south, a moderate westerly flow continues over the northern
Ohio Valley. Precipitable water values of near two inches or more
will continue through mid-day Friday, indicative of a tropical
airmass.
Quite a bit uncertainty still exists about where exactly convection
develops this evening. An circulation left over from last night`s
convection is now moving east northeast just to the south of St
Louis. This feature will move over southern Indiana late this
evening. This feature is supporting a cluster of thunderstorms now
moving east over western Kentucky. These storms are moving into an
unstable airmass southwest of Kentucky and should hold together
through this evening. Therefore, think storms late this afternoon
and early evening will become most numerous across west central
Kentucky, west of Interstate 65 and mostly to the south of
Interstate 64 across southern Indiana. A second area of convection
may drop south into south central Indiana late this evening. These
northern storms will form along a cold front slowly sagging south
across central Indiana. Will go likely for areas in Kentucky west of
Interstate 65 with scattered wording elsewhere.
Last night isolated storms over the Bluegrass produced very isolated
torrential rainfall amounts and flooding. This same scenario may play itself
out again tonight. Across south central Kentucky, localized heavy
rain and possible flooding are again possible in a few spots.
For Friday, a nearly stationary front will lie across southern
Indiana, nearly parallel to the Ohio River, any thunderstorm
development will highly depend on the location of any residual cloud
cover and outflow boundaries from overnight convection. Our best
moisture and convergence will lie over southern portions of our
Commonwealth. Slightly drier air will slowly filter in across
southern Indiana, limiting convective coverage there. Will continue
likely pops across southern Kentucky during the day Friday. Think
that any scattered storms will diminish across the north late
Friday, while hanging on near Tennessee.
Tonight will stay humid and muggy, with lows in the lower 70s, highs
Friday will reach the mid to upper 80s.
.LONG TERM (Saturday through Thursday)...
Issued at 309 PM EDT Thu Aug 8 2013
Quasi-stationary boundary laid out across the commonwealth will be
starting off this forecast period, allowing for the primary focus
for convection to be limited to southern portions of KY. Have
trended back PoPs for the northern half of the forecast area as such
since surface winds will have begun to back to the north by this
point, assuming the general deterministic model consensus holds
true. With the loss of daytime heating and as the front slowly
slides off to the south and east, have gone dry for the early
morning hours on Sunday. Couldn`t completely remove PoPs out of the
forecast for the afternoon hours as a surface low riding along the
frontal boundary traverses across from west to east, once again
serving as a focus for renewed convection chances as surface high
pressure centered over the southern Great Lakes fights for control
over us. This fight, however, is very short lived as the high moves
off toward the East Coast and the next frontal boundary approaches
the Ohio Valley. This front is seemingly much faster with strong
Canadian high pressure pushing it southward from behind. What this
translates to for us is a continued unsettled period from Monday
through Tuesday night. By Wednesday, am hopeful that the boundary
will be south of the TN border, although the 12Z GFS tries to keep
the southern tier of counties wet through Wednesday night. Even if
the timing ends up being slightly off, the end result will be the
same for all of us: clearing skies, a much drier airmass, and cool
temperatures for this time of year.
Speaking of temperatures, we`ll see highs ranging from the lower to
upper 80s throughout the entire period with the warmest day looking
to be Monday and the coolest day on Thursday. Dewpoints will keep it
muggy from this weekend through mid-week before a noticeable
difference comes in by Wednesday-Thursday. Lows will be near normal
Saturday night through Tuesday night, dropping off to below normal
by Wednesday night. Looking at 850mb anomalous temps on NCEP`s
ensemble, the cool temps are depicted to prevail under the
aforementioned high for much of the end of next week.
&&
.AVIATION (18Z TAF Update)...
Issued at 120 PM EDT Thu Aug 8 2013
Very humid air and a series of weak waves will bring scattered
convection across the region late this afternoon and evening.
Earlier convection around LEX will be diminishing by 18 to 19z, and
much of this evening until 01z or so should be dry.
On the other hand, scattered convection will begin to move towards
BWG after 20z and may periodically affect the terminal site through
the late evening hours. At SDF, convection will stay away from the
terminal through around 22z, after which, storms will become more
numerous late this evening towards midnight.
VFR conditions are expected at SDF through this evening, until
thunderstorms approach. At LEX and BWG, occasional broken ceilings
right around the MVFR/VFR threshold will continue through mid
afternoon, become more scattered this evening.
Winds will remain light from the southwest through early this
evening, then become light and variable overnight and Friday.
With scattered thunderstorm lasting possibly through the overnight
period, occasional MVFR visibilities and ceilings may be expected
through the morning hours. Scattered thunderstorms are possible
Friday.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJ
Short Term.....JSD
Long Term......LG
Aviation.......JSD
AREA FORECAST DISCUSSION
NWS JACKSON KY
255 PM EDT THU AUG 8 2013
.UPDATE...
ISSUED AT 255 PM EDT THU AUG 8 2013
MOST PRECIP HAS ENDED...WITH SCATTERED SHOWERS REMAINING AT MID
AFTERNOON. WILL LOOK FOR THEM TO PERSIST INTO THIS EVENING. CLOUDS
AND PRECIP HAVE SLOWED THE TEMPERATURE CLIMB...AND HAVE LOWERED
FORECAST MAX TEMPS SLIGHTLY FOR TODAY.
UPDATE ISSUED AT 1125 AM EDT THU AUG 8 2013
HEAVY RAINFALL DID NOT MATERIALIZE OVER THE FORECAST AREA THIS
MORNING...BUT STAYED TO OUR SOUTHWEST. THE MAIN PORTION OF AN MCS
REMAINED ANCHORED IN TN...WITH JUST DEBRIS/BLOW-OFF STREAMING OVER
OUR SOUTHERN COUNTIES IN KY. NOT CONFIDENT IN HEAVY RAINFALL TODAY
THROUGH FRIDAY...BUT WILL NOT DISPUTE THAT WITH THE HIGH MOISTURE
CONTENT OF THE ATMOSPHERE...RECENT HISTORY TO OUR WEST...AND WEAK TO
MODERATE LARGELY UNIDIRECTIONAL FLOW WITH HEIGHT...THAT SOME POTENTIAL
FOR TRAINING AND HEAVY RAINFALL EXISTS. WITH FFA ALREADY IN
PLACE...WILL LEAVE IT AS IS.
HAVE REDUCED POPS A BIT FOR TODAY...HOLDING ON TO LIKELY CATEGORY IN
OUR SOUTHEAST COUNTIES WHERE NUMEROUS SHOWERS WERE ONGOING LATE THIS
MORNING...BUT ONLY USING 50 PERCENT POPS ELSEWHERE.
UPDATE ISSUED AT 628 AM EDT THU AUG 8 2013
AFTER TALKING WITH NEIGHBORING OFFICES LMK AND RLX...AS WELL AS
SEEING THE LATEST HPC QPF GUIDANCE...MADE THE DECISION TO ISSUE AN
FFA FOR THE REGION THROUGH FRIDAY EVENING. SCT CONVECTION CONTINUES
TO DEVELOP ALONG THE BOUNDARY CURRENTLY PUSHING SOUTH INTO
KENTUCKY...WITH PWAT VALUES EXPECTED TO BE IN THE 2.0 AND ABOVE RANGE
FOR A 6 HOUR TIME PERIOD BOTH THIS MORNING AND FRIDAY MORNING. WITH
SOME OF THESE SHOWERS AND THUNDERSTORMS...RAIN RATES OF 2 TO 3 INCHES
AN HOUR ARE VERY POSSIBLE. LOCALIZED FLASH FLOODING WILL BE A THREAT
THEREFORE...ESPECIALLY IN AREAS THAT HAVE MULTIPLE STORMS PASS OVER
THEIR LOCATION IN THE NEXT 48 HOURS. LATEST NAM IS ALSO TARGETING
ANOTHER SWATH OF HEAVIER PRECIP MOVING INTO THE REGION SATURDAY
MORNING...AFTER THE EXPIRATION OF THE FFA. THIS IS SUBJECT TO CHANGE
WITH LATER MODEL RUNS...SO FIGURED IT WOULD BE EASIER TO EXTEND THE
FFA IN THE FUTURE IF NEEDED RATHER THAN HAVE TO CANCEL IT AND END UP
NEEDING TO REISSUE. THE LATEST SPENES PRODUCT FROM THE SATELLITE
BRANCH ALSO PINPOINTED A LARGE SECTION OF OUR SOUTHWESTERN CWA IN
THEIR AREA OF CONCERN FOR EXCESSIVE RAINFALL THIS MORNING. THIS JUST
FURTHER SOLIDIFIED THE DECISION TO GO AHEAD AND ISSUE THE FFA FOR THE
REGION.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE COLD FRONT THAT HAS REMAINED NEARLY STATIONARY JUST NORTH OF THE
OHIO RIVER VALLEY YESTERDAY WILL FINALLY BEGIN ITS PUSH SEWARD
ACROSS KY DURING THE DAY TODAY...REACHING THE SE PORTION OF THE
STATE BY EVENING. AS WAS THE CASE WITH THIS SYSTEM YESTERDAY...HIGH
HUMIDITY VALUES IN ADDITION TO THE ISENTROPIC LIFT PROVIDED BY THIS
FRONT WILL WORK TO SPAWN CONVECTION...ESPECIALLY WITH THE ADDITION
OF DAYTIME HEATING AND GREATER INSTABILITY. EXPECT A LARGE AREA OF
SHOWERS AND POTENTIAL THUNDERSTORMS TO DEVELOP JUST AHEAD OF THE
FRONT AND ENCOMPASS MUCH OF THE CWA...THEN SHIFT SLIGHTLY EASTWARD
AS THE FRONT NEARS INTO THE REGION. CURRENT RADAR TRENDS ARE ALREADY
SUPPORTING THIS IDEA...WITH SCATTERED SHOWERS CONTINUING TO DEVELOP
ACROSS THE WESTERN HALF OF THE CWA. WHILE MODELS REMAIN FAIRLY
CONSISTENT THAT PRECIP WILL OVERSPREAD THE AREA...THERE IS STILL
SOME SUBTLE DIFFERENCES IN RESOLUTION AS TO WHERE THE HEAVIEST
PRECIP WILL OCCUR. BASED ON THE LATEST HRRR AND NAM12...EXPECT BEST
PRECIP DEVELOPMENT ACROSS THE SOUTHERN EXTENT OF THE CWA IN THE
MORNING...SPREADING TO THE NORTH BY THE AFTERNOON.
BY 0Z FRIDAY...FRONT WILL ONCE AGAIN BECOME STATIONARY...THIS TIME
PARKING ITSELF ACROSS EASTERN KY. WITH SUCH HUMID AND UNSTABLE
CONDITIONS IN PLACE...WILL CONTINUE WITH ONGOING FORECAST OF SOME
SCT CONVECTIVE POSSIBILITY THROUGHOUT THE NIGHT...SINCE ANY STORM
ONGOING IN THE AFTERNOON WILL TAKE SOME TIME TO DIE OFF...AND THERE
IS ALWAYS THE POSSIBILITY THAT ANY LITTLE AREA OF LIFT COULD
INITIATE SOME MORE SHOWERS. LUCKILY...WITH LOSS OF DAYTIME
HEATING...BEST INSTABILITY AND THUNDERSTORM POTENTIAL WILL LESSON.
HIGH DEW POINTS WILL ALSO LEAD TO LITTLE VARIATION FOR
TEMPERATURES...WITH LOWS ONLY DROPPING TO AROUND 70.
FRIDAY WILL BRING ABOUT SIMILAR CONDITIONS TO TODAY...WITH THE
STATIONARY FRONT LIFTING SLIGHTLY JUST TO THE NORTH OF THE CWA. AN
UPPER LEVEL SHORTWAVE MOVING THROUGH EASTERN KY BY FRIDAY MORNING
WILL BE ENOUGH TO KICK START SHOWER AND THUNDERSTORM DEVELOPMENT
ACROSS THE REGION. WHILE PRECIPITABLE WATER VALUES WERE NEARING 2
INCHES FOR TODAY/S FORECAST...ACCORDING TO LATEST NAM12
SOUNDINGS...FRIDAY/S SOUNDINGS ARE POINTING AT WELL OVER 2.10 INCHES
IN MANY LOCATIONS WITHIN A 6 HOUR PERIOD. IF A STRONG SHOWER OR
THUNDERSTORM DEVELOPS AND MOVES OVER A PARTICULAR SITE...FLASH
FLOODING IS A DEFINITE THREAT...ESPECIALLY IF THEY ARE IMPACTED BY
TODAY/S CONVECTIVE ACTIVITY. MOST OF THIS MOISTURE IS EXPECTED TO
FALL DURING THE MORNING AND EARLY AFTERNOON HOURS...WITH PWAT VALUES
SLIGHTLY LESS...IN THE 1.5-2.0 RANGE IN THE AFTERNOON HOURS.
TEMPERATURES SHOULD REMAIN FAIRLY SIMILAR TO TODAY WITH LITTLE
CHANGE IN THE OVERALL PATTERN.
SINCE A LOT OF THE EXPECTED PRECIP IS BASED ON MESOSCALE
DEVELOPMENT...DISCUSSED THE IDEA OF ISSUING A FFA FOR THE AREA...BUT
ULTIMATELY DECIDED TO HOLD OFF FOR RIGHT NOW. FUTURE SHIFTS MAY
DECIDE TO PULL THE TRIGGER BASED ON HOW WIDESPREAD AND HEAVY THE
DAY/S CONVECTIVE DEVELOPMENT PROVES TO BE.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 413 AM EDT THU AUG 8 2013
THE MODELS CONTINUE TO BE IN GOOD AGREEMENT ON THE GENERAL UPPER AIR
PATTERN THAT WILL GUIDE OUR WEATHER THROUGH THE EXTENDED PORTION OF
THE FORECAST. THIS CONSISTS PRIMARILY OF A DEEP AND PERSISTENT
TROUGH OVER SOUTHEAST CANADA AND A FLAT RIDGE OVER THE SOUTHERN TIER
OF THIS NATION. BETWEEN THESE...FAIRLY FAST MID LEVEL FLOW WILL
CARRY SHORT WAVE ENERGY FROM THE WEST COAST THROUGH THE OHIO VALLEY
BEFORE EXITING OFF THE EASTERN SEABOARD. THIS FLOW WILL BE FAIRLY
ZONAL OVER KENTUCKY THROUGH THE WEEKEND BEFORE A WESTERN RESURGENCE
IN THE CANADIAN TROUGH INDUCES A DIP SOUTH THROUGH THE GREAT LAKES
AND INTO THE NORTHERN OHIO VALLEY. THIS WILL RESULT IN MORE OF A
NORTHWEST FLOW PATTERN FOLLOWING THE WEEKEND INTO THE MIDDLE OF NEXT
WEEK. THE GFS AND ECMWF DIFFER MOST DURING THE LATTER PORTION OF THE
FORECAST AS THE ECMWF RUNS A BIT FASTER AND FURTHER EAST WITH THE
CANADIAN LOW/S REDEVELOPMENT INTO THE DAY MONDAY. THE GFS TAKES THE
CORE OF THIS LOW FURTHER SOUTH ON TUESDAY...DIPPING INTO THE
STATES...BEFORE LIFTING IT JUST NORTH OF EAST. DURING THIS TIME OF
LARGER GFS/ECMWF DISCREPANCY THE GEM SEEMS TO BE SIDING WITH THE
ECMWF SO THE MORE EXTREME GFS SOLUTION FOR MONDAY TO WEDNESDAY WILL
BE DISCOUNTED. ALSO...ITS RUN TO RUN CONSISTENCY HAS BEEN POOR...NOT
THAT THE ECMWF HAS BEEN ALL THAT MUCH BETTER/JUST NOT SO OUT THERE
AT TIMES...FOR THE LATTER PART OF THE EXTENDED. ACCORDINGLY...WILL
FAVOR THE BLENDED RESULTS THROUGH THE WEEKEND BEFORE LEANING MORE
TOWARD THE ECMWF INTO THE MIDDLE OF NEXT WEEK.
SENSIBLE WEATHER WILL FEATURE A CONTINUATION OF OUR WET PATTERN THAT
IS PRIMED FOR BOUTS OF HEAVY RAIN. THE SFC BOUNDARY WILL REMAIN
STALLED THROUGH THE REGION INTO THE WEEKEND WITH EACH SFC WAVE
RIPPLING PAST...POTENTIALLY SENDING THE BOUNDARY AND ITS HEAVIEST
RAIN OUR WAY. HIGH PW AIR AND DAYTIME INSTABILITY WILL PROVIDE THE
FUEL FOR THIS MCS ACTIVITY. THEREFORE...POPS WILL REMAIN HIGH INTO
THE WEEKEND WITH MAX TEMPERATURES CAPPED BELOW NORMAL DUE TO CLOUDS
AND CONVECTION. FOR THE START OF NEXT WEEK...IT LOOKS LIKE THE
AMPLIFYING TROUGH ALOFT WILL BE ENOUGH TO EVENTUALLY PUSH THE FRONT
SOUTH OF THE AREA AND ALLOW DRIER AIR TO FLOW INTO THE STATE. THE
FAVORED 12Z ECMWF DOES TAKE THE DEEPER MOISTURE SOUTH LATER MONDAY
WHILE THE GFS WAITS UNTIL A SECONDARY FRONT PUSHES THROUGH ON
TUESDAY NIGHT. WILL CONTINUE SMALL POPS INTO TUESDAY FOR THIS
TRANSITION...BUT NOT AS HIGH AS THE GFS WOULD IMPLY. HOPEFULLY
WEDNESDAY WILL TURN OUT AS PLEASANT AS THE MODEL CONSENSUS SUGGESTS
WITH A RETURN OF DECENT SUNSHINE AND MUCH DRIER AIR. WE WILL SEE...
BUT AT LEAST THIS SEEMS TO BE A BUILDING AND STABILIZING ASPECT OF
THE FORECAST FROM THE LATEST MEDIUM RANGE MODELS.
THE CR GRID LOAD CAME IN NICELY FOR THIS UNSETTLED FORECAST THROUGH
THE WEEKEND. DID TWEAK POPS TO ADD MORE OF A DIURNAL CYCLE AND ALSO
TOWARD THE LATEST SPECIFICS FROM THE 12Z ECMWF FOR MONDAY ON INTO
WEDNESDAY. ONLY MADE MINOR TERRAIN BASED ADJUSTMENTS FOR TEMPS
THROUGHOUT THE BULK OF THIS EXTENDED PERIOD GIVEN THE HIGH MOISTURE
CONTENT...AT LEAST THROUGH TUESDAY MORNING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 255 PM EDT THU AUG 8 2013
WIDESPREAD MVFR WAS PRESENT AT THE START OF THE PERIOD. IMPROVEMENT
TO LARGELY VFR IS EXPECTED THIS AFTERNOON. HOWEVER...AREAS OF MVFR
AND IFR WILL PERSIST IN SCATTERED SHOWERS AND THUNDERSTORMS. THIS
SHOULD BE THE CASE INTO THE NIGHT. LATE TONIGHT A DETERIORATION TO
MVFR IS EXPECTED...WITH EVENTUAL IFR IN MANY AREAS ON FRIDAY MORNING.
THIS WILL OCCUR AS DUE TO THE LIKELIHOOD OF SHOWERS AND THUNDERSTORMS
DEVELOPING.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...HAL
SHORT TERM...JMW
LONG TERM...GREIF
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
205 PM EDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU AUG 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP MID LEVEL LOW OVER
NRN ONTARIO JUST E OF THE MANITOBA/ONTARIO BORDER. FOR THIS TIME OF
YEAR...THE LOW IS UNUSUALLY DEEP WITH 500MB HEIGHTS 2.5 STANDARD
DEVIATIONS BELOW THE LONG TERM AVG. THE UPPER LAKES ARE UNDER THE
SRN PORTION OF ITS RATHER EXPANSIVE CIRCULATION. IN THE WAKE OF THE
SHORTWAVES THAT PASSED ACROSS THE UPPER LAKES YESTERDAY...A DRY AIR
MASS HAS PUSHED INTO UPPER MI. COMBINED WITH CLEAR SKIES AND
LIGHT/CALM WIND...TEMPS HAVE ONCE AGAIN DIPPED AS LOW AS THE UPPER
30S IN SOME OF THE TRADITIONAL COLD SPOTS IN THE INTERIOR (DOE LAKE
AND SPINCICH LAKE IN PARTICULAR). JUST TO THE W...A SHORTWAVE THAT
WAS MUCH MORE WELL DEFINED YESTERDAY AFTN HAS WEAKENED/SHEARED E
INTO MN...AND IT IS SPREADING A BAND OF MID CLOUDS ACROSS NRN MN AND
WRN LAKE SUPERIOR. AFTER DIMINISHING...A BAND OF SHRA HAS
REDEVELOPED ACROSS NRN MN IN ASSOCIATION WITH THE SHORTWAVE. TO THE
NW OVER MANITOBA...A SHORTWAVE SPOKE IS EVIDENT ROTATING AROUND THE
DEEP MIDLEVEL LOW OVER NRN ONTARIO. BOTH OF THESE SHORTWAVES WILL
HAVE SOME IMPACT ON THE WEATHER HERE TODAY/TONIGHT.
FIRST UP...THE WEAKENING SHORTWAVE OVER MN WILL PASS ACROSS THE AREA
THIS MORNING. SEVERAL OF THE HIGH RES MODELS INCLUDING NAM AND HIGH
RES WRF-ARW/WRF-NMM HAVE DONE A NICE JOB PICKING UP ON THE LOCATION
OF SHRA TO THE W AND SUGGEST SHRA WILL TEND TO DISSIPATE AS THEY
SHIFT E INTO WRN UPPER MI THIS MORNING. WILL GENERALLY FOLLOW THIS
IDEA AND SPREAD ISOLD -SHRA INTO PORTIONS OF WRN UPPER MI THIS
MORNING. DURING THE AFTN...NEXT SHORTWAVE CURRENTLY ROTATING THRU
SRN MANITOBA SHOULD PROVIDE FORCING FOR ISOLD TO PERHAPS SCT AFTN
CONVECTION WITH LAKE BREEZES PROVIDING A LOW LEVEL FOCUS AS WELL.
WITH MLCAPES ONLY UP TO A COUPLE HUNDRED J/KG...THUNDER POTENTIAL IS
MINIMAL...BUT PROBABLY STILL WORTHY OF INCLUDING MENTION IN FCST.
ISOLD/SCT SHRA SHOULD SLOWLY SHIFT E AND SE TONIGHT AS PRONOUNCED
MID LEVEL DRYING PUSHES IN FROM THE W. THIS SHOULD ALSO LEAD TO
CLEARING OVER AT LEAST THE W HALF OR SO OF THE FCST AREA. LEANED
SOMEWHAT TOWARD THE LOWER SIDE OF AVBL GUIDANCE FOR MINS OVER THE W
WITH EXPECATION OF CLEARING AND A DRYING COLUMN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 518 AM EDT THU AUG 8 2013
OMEGA BLOCKING FROM ALASKA TO EASTERN CANADA WILL FINALLY BEGIN TO
BREAKDOWN...ALBEIT SLOWLY...BY THIS WEEKEND. BESIDE A CHANCE FOR
SHOWERS AND STORMS SUNDAY AFTERNOON INTO MONDAY NIGHT...THE LONG
TERM TREND WILL BE DRY AND SLIGHTLY COOLER THAN NORMAL.
FRIDAY THROUGH SATURDAY NIGHT...A DEEP CLOSED MID-LEVEL LOW OVER
NORTHERN ONTARIO WILL BE SENDING A SHORTWAVE TROUGH ACROSS THE CWA
THURSDAY NIGHT. THE ASSOCIATED COLD FRONT IS PROGGED TO CLEAR THE
CWA BY 12Z FRIDAY...WITH MUCH DRIER AIR USHERING IN BEHIND IT. SOME
LOW-LEVEL MOISTURE COULD LINGER ACROSS THE EAST HALF AFTER 12Z UNDER
INCREASING SUBSIDENCE BEHIND THE FRONT...SO KEPT SLIGHT CHANCE POPS
FOR A FEW HOURS BEYOND 12Z FOR THE FAR EAST.
THE MAIN TROUGH AXIS WILL THEN PUSH SOUTHEASTWARD ACROSS THE CWA
FRIDAY AFTERNOON INTO LATE FRIDAY NIGHT. WHILE MOISTURE IS LACKING
IN THE MID-LEVELS...H8 TO H7 FGEN UNDER MODEST MID-LEVEL
Q-VECTOR CONVERGENCE WILL LEAD TO INCREASED CLOUDINESS BELOW H5. THE
NAM IS THE ONLY MODEL TO INDICATE A SHOT AT ISOLATED SHOWERS ACROSS
THE NORTH CLOSER TO THE MAIN FORCING. HAVE OPTED TO KEEP ANY PRECIP
OUT OF THE FORECAST FOR NOW GIVEN VERY DRY LOW LEVELS AND THAT MOST
MODELS HAVE BEEN CONSISTENT WITH ALL PRECIP REMAINING OUT OF THE
CWA. MODEL TRENDS HAVE ALSO SHOWED A STRONGER PRESSURE
GRADIENT...ESPECIALLY NORTH....WITH THE TROUGH PASSAGE. WEAK
STABILITY SUGGESTS THAT MIXING COULD BRING GUSTY WNW OF UP TO 25 MPH
TO MUCH OF THE NORTH HALF BY THE AFTERNOON.
SFC HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WITH
MID-LEVEL SHORTWAVE RIDGING FRIDAY NIGHT THROUGH SATURDAY. GENERALLY
CLEAR SKIES AND LOW PWATS OF AROUND 0.5 INCHES WILL BE CONDUCIVE FOR
GOOD RADIATIONAL COOLING ACROSS MUCH OF THE CWA...PARTICULARLY THE
INTERIOR WEST HALF. HAVE FOLLOWED THE PREVIOUS SHIFTS TREND OF
LOWERING TEMPS. WIDESPREAD 40S ARE LIKELY FOR ALL BUT THE IMMEDIATE
GREAT LAKES SHORELINES. WEAK LOW-LEVEL MOISTURE RETURN WILL BEGIN
ACROSS THE WEST SATURDAY AFTERNOON AS THE SFC HIGH MOVES EAST. WITH
THIS MOISTURE INCREASE...AFTERNOON CUMULUS DEVELOPMENT WILL BE
COMMON. A FEW ISOLATED DIURNAL SHOWERS COULD EVEN BE POSSIBLE...BUT
ONCE AGAIN...CONFIDENCE IS TOO LOW TO INTRODUCE ANY PRECIP ATTM. LOW
TO MID-LEVEL CLOUDINESS WILL CONTINUE TO INCREASE WITH THE MOISTURE
RETURN SATURDAY NIGHT...KEEPING TEMPS SEVERAL DEGREES WARMER THAN
FRIDAY NIGHT.
SUNDAY THROUGH MONDAY...ANOTHER SHORTWAVE TROUGH ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN MID-LEVEL TROUGH WILL BE DIGGING SOUTHWARD
ACROSS FAR WESTERN ONTARIO LATE SATURDAY NIGHT. THE ECMWF HAS SLOWED
THIS TROUGH PASSAGE OVER THE LAST FEW RUNS...AND NOW LINES UP WELL
WITH THE GFS IN BRINGING THE MAIN TROUGH AXIS THROUGH MONDAY
EVENING. BOTH MODELS HAVE ALSO RECENTLY PICKED UP ON A WEAK LEAD
SHORTWAVE TROUGH FROM PHASING BETWEEN A PORTION OF THE MAIN TROUGH
AND A WEAK WAVE MOVING EASTWARD FROM WESTERN CANADA. THE TIMING OF
THIS WEAK WAVE IS A LITTLE DIFFERENT BETWEEN THE TWO MODELS...WITH
THE CONSENSUS BEING EARLY SUNDAY EVENING. INSTABILITY WILL BE QUITE
POOR NORTH OF THE WI BORDER AND SHOULD PRECLUDE ANY STRONG
THUNDERSTORM THREAT ATTM. THE TROUGH WILL CONTINUE TO SLOWLY WORK
EASTWARD ACROSS THE CWA AND BRING ISOLATED TO SCATTERED SHOWERS
THROUGH MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...BY THIS POINT...THE ECMWF AND GFS
HAVE SOME DISAGREEMENT ON THE STRENGTH OF THE SHORTWAVE...AND HOW
QUICK IT WILL DEPART. THE ECMWF IS MUCH QUICKER AND BRINGS GENERALLY
DRY CONDITIONS THROUGH WEDNESDAY. THE GFS SWINGS A STRONG SECONDARY
TROUGH ACROSS THE EASTERN CWA ON TUESDAY...BUT LIMITS SHOWERS TO
ONLY THE EAST HALF. STUCK WITH OVERALL MODEL CONSENSUS FOR
NOW...THROUGH MUCH OF THE PERIOD SHOULD REMAIN DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 205 PM EDT THU AUG 8 2013
CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. A WEAK
LOW PRESSURE TROUGH IS CROSSING UPPER MICHIGAN THIS AFTERNOON...AND
HAS LED TO THE DEVELOPMENT OF ISOLATED RAIN SHOWERS ACROSS MAINLY
WESTERN AND FAR NORTH CENTRAL UPPER MICHIGAN. THESE SHOWERS HAVE
BEEN VERY LIGHT...AND ARE EXPECTED TO CONTINUE TO DEVELOP NEAR
KSAW/KCMX/KIWD THROUGH EARLY EVENING. KIWD HAS THE BEST CHANCE
EARLIER ON...AS SHOWERS ARE JUST PASSING BAYFIELD WI. IN HEAVIER
SHOWERS CONDITIONS COULD DROP TO MVFR...HOWEVER NOT CONFIDENT ENOUGH
TO PUT IN THE TAF. HAVE KEPT VCSH IN FOR NOW. TOMORROW AFTERNOON YET
ANOTHER TROUGH WILL MAKE ITS WAY INTO THE U.P. EXCEPT THE AIRMASS IS
MUCH DRIER THAN TODAY. EXPECTING THAT KCMX HAS THE ONLY CHANCE OF
SEEING THESE SHOWERS...AND WAS NOT CONFIDENT ENOUGH TO PLACE IN THE
TAF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT THU AUG 8 2013
EXPECT WINDS UNDER 20KT ACROSS LAKE SUPERIOR TODAY/TONIGHT UNDER A
GENERALLY WEAK PRES GRADIENT. HOWEVER...WINDS WILL BEGIN TO INCREASE
OVERNIGHT TONIGHT AHEAD OF THE NEXT COLD FRONT DROPPING SE. AN
INCREASING PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM
SOUTH CENTRAL CANADA AND LOW PRESSURE EXITING TO THE EAST ACROSS
EASTERN ONTARIO WILL CREATE W TO WNW WINDS OF 15 TO 25 KNOTS ACROSS
WESTERN LAKE SUPERIOR FRIDAY MORNING...AND CENTRAL AND EASTERN LAKE
SUPERIOR FRIDAY AFTERNOON. WEST WINDS UNDER 15 KNOTS WILL THEN BE THE
RULE THROUGH THE WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE UPPER
GREAT LAKES. ANOTHER TROUGH WILL CROSS LAKE SUPERIOR ON MONDAY AND
BRING NW WINDS UNDER 15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...MCD
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
137 PM EDT THU AUG 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 518 AM EDT THU AUG 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A DEEP MID LEVEL LOW OVER
NRN ONTARIO JUST E OF THE MANITOBA/ONTARIO BORDER. FOR THIS TIME OF
YEAR...THE LOW IS UNUSUALLY DEEP WITH 500MB HEIGHTS 2.5 STANDARD
DEVIATIONS BELOW THE LONG TERM AVG. THE UPPER LAKES ARE UNDER THE
SRN PORTION OF ITS RATHER EXPANSIVE CIRCULATION. IN THE WAKE OF THE
SHORTWAVES THAT PASSED ACROSS THE UPPER LAKES YESTERDAY...A DRY AIR
MASS HAS PUSHED INTO UPPER MI. COMBINED WITH CLEAR SKIES AND
LIGHT/CALM WIND...TEMPS HAVE ONCE AGAIN DIPPED AS LOW AS THE UPPER
30S IN SOME OF THE TRADITIONAL COLD SPOTS IN THE INTERIOR (DOE LAKE
AND SPINCICH LAKE IN PARTICULAR). JUST TO THE W...A SHORTWAVE THAT
WAS MUCH MORE WELL DEFINED YESTERDAY AFTN HAS WEAKENED/SHEARED E
INTO MN...AND IT IS SPREADING A BAND OF MID CLOUDS ACROSS NRN MN AND
WRN LAKE SUPERIOR. AFTER DIMINISHING...A BAND OF SHRA HAS
REDEVELOPED ACROSS NRN MN IN ASSOCIATION WITH THE SHORTWAVE. TO THE
NW OVER MANITOBA...A SHORTWAVE SPOKE IS EVIDENT ROTATING AROUND THE
DEEP MIDLEVEL LOW OVER NRN ONTARIO. BOTH OF THESE SHORTWAVES WILL
HAVE SOME IMPACT ON THE WEATHER HERE TODAY/TONIGHT.
FIRST UP...THE WEAKENING SHORTWAVE OVER MN WILL PASS ACROSS THE AREA
THIS MORNING. SEVERAL OF THE HIGH RES MODELS INCLUDING NAM AND HIGH
RES WRF-ARW/WRF-NMM HAVE DONE A NICE JOB PICKING UP ON THE LOCATION
OF SHRA TO THE W AND SUGGEST SHRA WILL TEND TO DISSIPATE AS THEY
SHIFT E INTO WRN UPPER MI THIS MORNING. WILL GENERALLY FOLLOW THIS
IDEA AND SPREAD ISOLD -SHRA INTO PORTIONS OF WRN UPPER MI THIS
MORNING. DURING THE AFTN...NEXT SHORTWAVE CURRENTLY ROTATING THRU
SRN MANITOBA SHOULD PROVIDE FORCING FOR ISOLD TO PERHAPS SCT AFTN
CONVECTION WITH LAKE BREEZES PROVIDING A LOW LEVEL FOCUS AS WELL.
WITH MLCAPES ONLY UP TO A COUPLE HUNDRED J/KG...THUNDER POTENTIAL IS
MINIMAL...BUT PROBABLY STILL WORTHY OF INCLUDING MENTION IN FCST.
ISOLD/SCT SHRA SHOULD SLOWLY SHIFT E AND SE TONIGHT AS PRONOUNCED
MID LEVEL DRYING PUSHES IN FROM THE W. THIS SHOULD ALSO LEAD TO
CLEARING OVER AT LEAST THE W HALF OR SO OF THE FCST AREA. LEANED
SOMEWHAT TOWARD THE LOWER SIDE OF AVBL GUIDANCE FOR MINS OVER THE W
WITH EXPECATION OF CLEARING AND A DRYING COLUMN.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 518 AM EDT THU AUG 8 2013
OMEGA BLOCKING FROM ALASKA TO EASTERN CANADA WILL FINALLY BEGIN TO
BREAKDOWN...ALBEIT SLOWLY...BY THIS WEEKEND. BESIDE A CHANCE FOR
SHOWERS AND STORMS SUNDAY AFTERNOON INTO MONDAY NIGHT...THE LONG
TERM TREND WILL BE DRY AND SLIGHTLY COOLER THAN NORMAL.
FRIDAY THROUGH SATURDAY NIGHT...A DEEP CLOSED MID-LEVEL LOW OVER
NORTHERN ONTARIO WILL BE SENDING A SHORTWAVE TROUGH ACROSS THE CWA
THURSDAY NIGHT. THE ASSOCIATED COLD FRONT IS PROGGED TO CLEAR THE
CWA BY 12Z FRIDAY...WITH MUCH DRIER AIR USHERING IN BEHIND IT. SOME
LOW-LEVEL MOISTURE COULD LINGER ACROSS THE EAST HALF AFTER 12Z UNDER
INCREASING SUBSIDENCE BEHIND THE FRONT...SO KEPT SLIGHT CHANCE POPS
FOR A FEW HOURS BEYOND 12Z FOR THE FAR EAST.
THE MAIN TROUGH AXIS WILL THEN PUSH SOUTHEASTWARD ACROSS THE CWA
FRIDAY AFTERNOON INTO LATE FRIDAY NIGHT. WHILE MOISTURE IS LACKING
IN THE MID-LEVELS...H8 TO H7 FGEN UNDER MODEST MID-LEVEL
Q-VECTOR CONVERGENCE WILL LEAD TO INCREASED CLOUDINESS BELOW H5. THE
NAM IS THE ONLY MODEL TO INDICATE A SHOT AT ISOLATED SHOWERS ACROSS
THE NORTH CLOSER TO THE MAIN FORCING. HAVE OPTED TO KEEP ANY PRECIP
OUT OF THE FORECAST FOR NOW GIVEN VERY DRY LOW LEVELS AND THAT MOST
MODELS HAVE BEEN CONSISTENT WITH ALL PRECIP REMAINING OUT OF THE
CWA. MODEL TRENDS HAVE ALSO SHOWED A STRONGER PRESSURE
GRADIENT...ESPECIALLY NORTH....WITH THE TROUGH PASSAGE. WEAK
STABILITY SUGGESTS THAT MIXING COULD BRING GUSTY WNW OF UP TO 25 MPH
TO MUCH OF THE NORTH HALF BY THE AFTERNOON.
SFC HIGH PRESSURE WILL THEN BUILD INTO THE UPPER GREAT LAKES WITH
MID-LEVEL SHORTWAVE RIDGING FRIDAY NIGHT THROUGH SATURDAY. GENERALLY
CLEAR SKIES AND LOW PWATS OF AROUND 0.5 INCHES WILL BE CONDUCIVE FOR
GOOD RADIATIONAL COOLING ACROSS MUCH OF THE CWA...PARTICULARLY THE
INTERIOR WEST HALF. HAVE FOLLOWED THE PREVIOUS SHIFTS TREND OF
LOWERING TEMPS. WIDESPREAD 40S ARE LIKELY FOR ALL BUT THE IMMEDIATE
GREAT LAKES SHORELINES. WEAK LOW-LEVEL MOISTURE RETURN WILL BEGIN
ACROSS THE WEST SATURDAY AFTERNOON AS THE SFC HIGH MOVES EAST. WITH
THIS MOISTURE INCREASE...AFTERNOON CUMULUS DEVELOPMENT WILL BE
COMMON. A FEW ISOLATED DIURNAL SHOWERS COULD EVEN BE POSSIBLE...BUT
ONCE AGAIN...CONFIDENCE IS TOO LOW TO INTRODUCE ANY PRECIP ATTM. LOW
TO MID-LEVEL CLOUDINESS WILL CONTINUE TO INCREASE WITH THE MOISTURE
RETURN SATURDAY NIGHT...KEEPING TEMPS SEVERAL DEGREES WARMER THAN
FRIDAY NIGHT.
SUNDAY THROUGH MONDAY...ANOTHER SHORTWAVE TROUGH ON THE BACKSIDE OF
THE DEEP EASTERN CANADIAN MID-LEVEL TROUGH WILL BE DIGGING SOUTHWARD
ACROSS FAR WESTERN ONTARIO LATE SATURDAY NIGHT. THE ECMWF HAS SLOWED
THIS TROUGH PASSAGE OVER THE LAST FEW RUNS...AND NOW LINES UP WELL
WITH THE GFS IN BRINGING THE MAIN TROUGH AXIS THROUGH MONDAY
EVENING. BOTH MODELS HAVE ALSO RECENTLY PICKED UP ON A WEAK LEAD
SHORTWAVE TROUGH FROM PHASING BETWEEN A PORTION OF THE MAIN TROUGH
AND A WEAK WAVE MOVING EASTWARD FROM WESTERN CANADA. THE TIMING OF
THIS WEAK WAVE IS A LITTLE DIFFERENT BETWEEN THE TWO MODELS...WITH
THE CONSENSUS BEING EARLY SUNDAY EVENING. INSTABILITY WILL BE QUITE
POOR NORTH OF THE WI BORDER AND SHOULD PRECLUDE ANY STRONG
THUNDERSTORM THREAT ATTM. THE TROUGH WILL CONTINUE TO SLOWLY WORK
EASTWARD ACROSS THE CWA AND BRING ISOLATED TO SCATTERED SHOWERS
THROUGH MONDAY AFTERNOON.
MONDAY NIGHT THROUGH WEDNESDAY...BY THIS POINT...THE ECMWF AND GFS
HAVE SOME DISAGREEMENT ON THE STRENGTH OF THE SHORTWAVE...AND HOW
QUICK IT WILL DEPART. THE ECMWF IS MUCH QUICKER AND BRINGS GENERALLY
DRY CONDITIONS THROUGH WEDNESDAY. THE GFS SWINGS A STRONG SECONDARY
TROUGH ACROSS THE EASTERN CWA ON TUESDAY...BUT LIMITS SHOWERS TO
ONLY THE EAST HALF. STUCK WITH OVERALL MODEL CONSENSUS FOR
NOW...THROUGH MUCH OF THE PERIOD SHOULD REMAIN DRY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 136 PM EDT THU AUG 8 2013
CONDITIONS ARE EXPECTED TO REMAIN VFR THROUGH THE TAF PERIOD. A WEAK
LOW PRESSURE TROUGH IS CROSSING UPPER MICHIGAN THIS AFTERNOON...AND
HAS LED TO THE DEVELOPMENT OF ISOLATED RAIN SHOWERS ACROSS MAINLY
WESTERN AND FAR NORTH CENTRAL UPPER MICHIGAN. THESE SHOWERS HAVE
BEEN VERY LIGHT...AND ARE EXPECTED TO CONTINUE TO DEVELOP NEAR
MAINLY KSAW/KCMX THROUGH EARLY EVENING. IN HEAVIER SHOWERS
CONDITIONS COULD DROP TO MVFR...HOWEVER NOT CONFIDENT ENOUGH TO PUT
IN THE TAF. TOMORROW AFTERNOON YET ANOTHER TROUGH WILL MAKE ITS WAY
INTO THE U.P. EXCEPT THE AIRMASS IS MUCH DRIER THAN TODAY. EXPECTING
THAT KCMX HAS THE ONLY CHANCE OF SEEING THESE SHOWERS...AND WAS NOT
CONFIDENT ENOUGH TO PLACE IN THE TAF.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 518 AM EDT THU AUG 8 2013
EXPECT WINDS UNDER 20KT ACROSS LAKE SUPERIOR TODAY/TONIGHT UNDER A
GENERALLY WEAK PRES GRADIENT. HOWEVER...WINDS WILL BEGIN TO INCREASE
OVERNIGHT TONIGHT AHEAD OF THE NEXT COLD FRONT DROPPING SE. AN
INCREASING PRESSURE GRADIENT BETWEEN HIGH PRESSURE BUILDING IN FROM
SOUTH CENTRAL CANADA AND LOW PRESSURE EXITING TO THE EAST ACROSS
EASTERN ONTARIO WILL CREATE W TO WNW WINDS OF 15 TO 25 KNOTS ACROSS
WESTERN LAKE SUPERIOR FRIDAY MORNING...AND CENTRAL AND EASTERN LAKE
SUPERIOR FRIDAY AFTERNOON. WEST WINDS UNDER 15 KNOTS WILL THEN BE THE
RULE THROUGH THE WEEKEND AS THE HIGH PRESSURE SETTLES OVER THE UPPER
GREAT LAKES. ANOTHER TROUGH WILL CROSS LAKE SUPERIOR ON MONDAY AND
BRING NW WINDS UNDER 15 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KLUBER
AVIATION...MCD
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
111 PM CDT Thu Aug 8 2013
.UPDATE:
Issued at 1004 AM CDT Thu Aug 8 2013
Have updated forecast to reflect that area of showers and thunderstorms
over the Ozarks continues to moves east and slightly north. In addition,
scattered thunderstorms have developed recently along the across
Gasconade and Franklin counties. Latest runs of the HRRR and RAP
are showing that a low level moisture convergence maximum will
move east into southern Illinois later this morning. Now believe
that north edge of the rain will move north to about the Missouri
River before diminishing with greatest chances shifting eastward
from the Ozarks into southern Illinois. Will keep with the idea
that areal coverage of the rain will diminish early-mid afternoon.
Then the atmosphere will become increasing unstable by late
afternoon, particularly over southern Missouri at the same time
that low level moisture convergences increases from southern
Missouri into central Missouri between 21-00Z. HRRR reflectivity
shows that discrete storms may initially develop late this
afternoon into early this evening. A few severe thunderstorms will
be possible depending on the amount of instability that is able to
work into the area. Storms will also be possible of producing
heavy rainfall rates.
Britt
&&
.SHORT TERM: (Through Sunday)
Issued at 404 AM CDT Thu Aug 8 2013
Cold front is now over southern portions of forecast area early
this morning. Storms that had fired along it have long since
dissipated. Otherwise...storms have fired on nose of low level jet
once again, but further south over far southwestern Missouri.
Also, an MCS has developed over north central Oklahoma and it`s
associated MCV will continue to track to the east along frontal
boundary today. So will see scattered storms fire and move along
front, making some progress to the north, but remain along and
south of I-70. Because of the light surface winds and plenty of
low level moisture, some patchy dense fog has developed over far
southern and eastern portions of forecast area this morning, but
should dissipate as high and mid clouds move in later this
morning. As for high temperatures, low to mid 80s a good bet.
By tonight, models continue to develop another MCS over eastern
Kansas and slide it east, but have differing opinions on placement
of system, with NAM the furthest north. Will go with a blend of the
models and keep likely pops going for tonight for a good portion of
the forecast area, but back off main area of activity til after 06z
and continue through day on Friday before tapering off Friday night.
Will see decent qpf amounts, but placement of heaviest rains still
hard to pin down, so will not issue a Flash Flood Watch at this
time. One may be needed for late tonight through Friday,
especially for central and southern portions of forecast area. Lows
tonight will be in the mid 60s to around 70 with highs on Friday
in the upper 70s to mid 80s.
Weak surface ridge is still expected to build in for the weekend and
into early next week, so precipitation chances to shift off to the
south, though kept chance pops for southeast Missouri and far
southwestern Illinois through Sunday. Highs to remain below normal
in the low to mid 80s through the weekend.
Byrd
.LONG TERM: (Sunday Night through Wednesday)
Issued at 404 AM CDT Thu Aug 8 2013
Surface ridge to move off to the east ahead of next weather system
by Monday, so have chances of showers and thunderstorms across the
area on Monday as system moves through, tapering off Monday night.
Then dry conditions return to the region for the rest of the
forecast period with below normal temperatures.
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Friday Afternoon)
Issued at 111 PM CDT Thu Aug 8 2013
Area of showers and thunderstorms is quickly diminishing as it
moves east. Still expect 1-2 more hours of light rain at the St.
Louis metro area TAF sites before it ends. There will also be some
lingering MVFR (isolated IFR) ceilings and visibilities before
turning VFR later this afternoon. Additional thunderstorm
development will be possible later this afternoon and this
evening...particularly over southern Missouri. Better chance for
rain with MVFR ceilings and visibilities will be between 06-14Z
Saturday when another complex of thunderstorms is expected to move
across southern Missouri.
Specifics for KSTL: Expect dry and VFR conditions to return to
airport in the next hour. Airport may see additional thunderstorms
late tonight and early Saturday on the northern fringe of another
complex of storms. This rain may bring MVFR ceilings and
visibilities with it.
Britt
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1226 PM CDT Thu Aug 8 2013
.SHORT TERM...(Today through Friday)
Issued at 322 AM CDT THU AUG 8 2013
Another night of conceptual forecasting as none of the 00Z solutions
have initialized the anticipated MCS riding along the KS/OK border,
and continue to poorly handle the subtle but key features emanating
out of the western trough each afternoon. The HRRR continues to
perform exceptionally well (albeit slow on timing), but its short-
term guidance only goes so far. In any case, 07Z surface analysis
depicts a strongly convergent frontal zone across nrn OK/AR with the
greatest lift once again focused about 50 miles north of this
boundary. A secondary elevated boundary, roughly juxtaposed with the
southern extent of dry surface air, extends NE from Wichita to
Clinton to Jefferson City. Developing MCV along over SW KS will
likely begin to make the turn ENE along this northern boundary.
With that said, dry northeasterly flow should keep most of the CWA
quiet through daybreak. Much like the past several nights, a sub-
synoptic occlusion should occur as the eastward advancing MCS
overtakes the W-E stationary front. This would place the southwestern
zones under the best chances for thunder by 12Z, with a rapid
transition to a stratiform rain/embedded thunder event as an
enlarging precipitation shield pushes into the dry air over east
central KS/west central MO. A well-defined MCV should lift slowly
across the southern CWA during the day, with QPF diminishing.
The MCV passage will mark the return of deeper warm/air moisture
advection that will place us back in a preferred zone for deep moist
convection tonight and Friday. As for highs today, generally went
around 80 across the board. Despite better chances for sunshine over
the NE CWA (at least early), CAA should yield similar readings as
points further south. Convective debris/showers should limit
insolation over the srn CWA through the morning, but expect some PM
sun to boost them back up.
For tonight, the large scale mid-level trough will begin to
finally eject out of the central Rockies, establishing a surface low
across OK. Deepening southwesterly flow aloft will lift the surface
warm front back to near I-44. This will place the southern CWA in a
precarious region of strong deep layer ascent/convergence amidst
increasing moisture advection. Based only on persistence from the
past 4-5 days, greatest QPF should fall in the 06-15Z time frame
Friday. Given the frontogenetic forcing, upper support and boundary-
relative shear profiles, have significantly bumped POPs and QPF from
06Z-18Z Friday. A flash flood watch will likely be required south of
the MO river given antecedent rainfall and prospects for very heavy
rainfall tonight/Friday morning.
Highs Friday honestly a hedge toward some afternoon clearing, but
could conceivably end up in the low-mid 70s if this doesn`t occur.
Friday Night remains the biggest question mark given the large model
spread in timing of the upper trough passage. Areas along/ahead of
this mid level wind shift certainly remain under the gun for
additional precipitation and have retained moderate POPs across all
but far NW MO for that reason.
.LONG TERM...(Saturday through Wednesday)
Issued at 322 AM CDT THU AUG 8 2013
The upcoming weekend should remain dry as the region will fall under
the influence of high pressure moving southeast through the Great
Lakes. With little change in the synoptic pattern and a continuance
of progressive zonal to northwesterly flow heading into into next
week, it appears there will only be a short break to the rainfall in
the region. By Monday, upper troughing will temporarily deepen over
Manitoba and Ontario, pushing a weak shortwave into the Central
Plains. Increasing warm advection ahead of this wave will induce
showers and thunderstorms over a large area of the central CONUS
Monday into Monday night. Have increased PoPs from late Sunday
night into Tuesday morning.
Latest guidance suggests a cold front will sweep southward through
the region by Tuesday morning, with high pressure once again moving
into the western Great Lakes providing dry conditions to the local
area.
As far as temperatures are concerned, warm advection and
southwesterly surface flow on Sunday will push temperatures back
towards seasonal normals. However, past the frontal passage on
Tuesday, temperatures will likely remain below normal into the
middle of next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1226 PM CDT THU AUG 8 2013
Over the next 2-3 hours, scattered light rain showers will continue
to lift east northeast across central and northeast KS, but will
gradually erode just east of the Missouri border. Ceilings with this
area of precipitation should stay around 10 kft; thus, much of the
region should remain VFR through at least 09z. Showers and storms are
still expected to develop across south central KS after midnight and
lift into the region between 09z-12z Friday. Most precipitation
should remain focused along and south of I-70, and should begin to
weaken and push off to the east around 18z Friday. Winds will remain
around or less than 10 kts through the period, varying in direction
from northeast to east.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...FLASH FLOOD WATCH from Midnight CDT tonight through Friday
morning FOR KSZ057-060-105.
MO...FLASH FLOOD WATCH from Midnight CDT tonight through Friday
morning FOR MOZ037>040-043>046-053-054.
&&
$$
SHORT TERM...Bookbinder
LONG TERM...Dux
AVIATION...Laflin
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
342 PM CDT THU AUG 8 2013
.DISCUSSION...
MAIN SHORT TERM CONCERN IS POPS THROUGH TONIGHT AS SCATTERED
SHOWERS CONTINUE TO DRIFT EAST ACROSS THE CWA.
LATEST WATER VAPOR IMAGERY AND LATEST RAP 500MB ANALYSIS SHOW A
LARGE UPPER LOW OVER ONTARIO WITH A RIDGE EXTENDING FROM THE FOUR
CORNERS REGION INTO BRITISH COLUMBIA. IN BETWEEN THIS...A WEAK
SHORTWAVE EXTENDS FROM EASTERN NEBRASKA INTO NORTHEAST KANSAS WITH
ANOTHER CIRCULATION IN SOUTH CENTRAL COLORADO.
THE SHORTWAVE ENERGY OVER THE REGION CONTINUES TO SUPPORT AN AREA
OF WIDELY SCATTERED SHOWERS OVER THE FORECAST AREA. THE LATEST RAP
SEEMS TO HAVE A GOOD HANDLE...ALBEIT A BIT OVERDONE ON QPF...AND
HAVE FOLLOWED MORE CLOSELY TO ITS TRENDS. UPPER LEVEL SUPPORT WILL
MOVE OUT OF THE AREA EARLY THIS EVENING SO HAVE ONLY CARRIED A
MENTION OF PCPN THROUGH THIS TIME. DID CONTINUE A MENTION OF SMALL
POPS IN THE FAR SOUTHEAST AFTER 06Z WITH SOME WEAK UPPER LEVEL
SUPPORT REMAINING INTO THE MORNING.
FRIDAY CONTINUES TO LOOK MOSTLY DRY BUT DID KEEP A SMALL POP IN
FOR THE SOUTH WITH SOME WEAK UPPER LEVEL SUPPORT IN THE AREA.
WITH MID/UPPER LEVEL FLOW OUT OF THE NORTHWEST THROUGH THE
WEEKEND...AND INCREASING WAA REGIME...WILL KEEP SOME SCATTERED
POPS ACROSS THE AREA...MAINLY IN THE NORTH. A STRONGER SHORTWAVE
WILL SLIDE ACROSS SOUTH DAKOTA THROUGH THE NORTHWEST FLOW
SATURDAY...SO BEST CHANCES WILL BE IN THE NORTH...ALTHOUGH WE
SHOULD NOTE THAT THE NEW 12Z ECMWF IS TRENDING THIS WAVE A BIT
FARTHER SOUTH.
ON AND OFF AGAIN SHOWERS AND TSTMS CANNOT BE RULED OUT THROUGH THE
EXTENDED WITH WEAK UPPER LEVEL SUPPORT SLIDING THROUGH THE REGION.
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.
VFR CONDITIONS ARE EXPECTED TO CONTINUE AT ALL THREE SITES
FOR MUCH OF THE PERIOD. KOFK LIKELY TO SEE SOME PATCHY LIGHT
SHOWERS INTO TONIGHT BUT KOMA AND KLNK SHOULD STAY DRY. A PERIOD
OF MVFR FOG ALSO POSSIBLE AT KOFK TOWARDS DAWN.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1143 AM MDT THU AUG 8 2013
.AVIATION...
18Z TAF CYCLE
SHOWERS AND THUNDERSTORMS WILL FAVOR NORTH-CENTRAL AND NORTHEASTERN
NEW MEXICO THIS AFTERNOON AND EVENING WITH ISOLATED COVERAGE ELSEWHERE.
THE STRONGER SHOWERS AND THUNDERSTORMS WILL PRODUCE DOWNPOURS CAPABLE
OF REDUCING VISIBILITIES/CEILINGS BRIEFLY. CONVECTIVE COMPLEX OVER
NORTHEAST NM/SOUTHEAST CO WILL SEND A RAIN COOLED AIRMASS SOUTHWESTWARD
THROUGH THE PLAINS AND THROUGH THE CANYONS OF THE CENTRAL MTN CHAIN
LATE THIS EVENING. LIGHT TO MODERATE EAST/SOUTHEAST WINDS ARE
EXPECTED AT KSAF AND KABQ AROUND 06Z.
33
.PREV DISCUSSION...330 AM MDT THU AUG 8 2013...
SURFACE BOUNDARY ATTM IN APPROXIMATELY THE SAME LOCATION AS ONE 24
HOURS. STILL CONSIDERABLE MOISTURE LINGERING OVER THE STATE WITH
SIGNIFICANTLY DRIER DEWPOINTS AS WELL AS A MUCH DRIER AIR MASS
OVERALL ACROSS CENTRAL/WRN AZ. SOMEWHAT MORE ORGANIZED CLOUD COVER
ROTG SE OVER THE FOUR CORNERS REGION...AND RUC13 CONTINUES TO
ANALYZE A WEAK CLOSED CIRCULATION AT H5 OVER NW NM/SW CO THROUGH
EARLY THIS AFTERNOON. AS THE DAY PROGRESSES...A SURFACE BOUNDARY IS
FORECAST TO BECOME MORE DEFINED OVER NE NM. THEREFORE HAVE TRENDED
TOWARDS THE HIGHER GUIDANCE POPS TODAY FOR THE NORTHEAST THIRD TO
HALF OF THE FORECAST AREA. LATEST SPC OUTLOOK HAS SLIGHT RISK FOR
SVR STORMS IN AN AREA SIMILAR TO WHAT WAS PREDICTED 24 HOURS AGO.
HAVE NOT HIGHLIGHTED THAT POSSIBILITY IN THE WX GRIDS...SO LATER
SHIFTS WILL NEED TO MONITOR.
FRONT TO PLUNGE INTO THE EASTERN PLAINS TONIGHT BUT NOT MUCH
INDICATION MODEL WISE IT WILL REACH THE RGV. FRIDAY NIGHT APPEARS AS
IF THIS POSSIBILITY IS MORE LIKELY...TRENDING SHOWER AND STORM
CHANCES UPWARD AND WESTWARD. HIGHS TODAY WILL BE A FEW DEGREES
BELOW AVERAGE MAINLY NORTH OF INTERSTATE 40...AND MAINLY OVER THE
NORTHEAST QUARTER FRIDAY. WITH POTENTIAL FORECAST FOR A MONSOON
BURST...HIGHS SATURDAY ACROSS THE NORTHWEST HALF WILL BE SEVERAL
DEGREES BELOW AVERAGE.
ANOTHER TRANSITION FORECAST IN THE WEATHER PATTERN FOR NEXT
WEEK...WITH A TREND TOWARDS WARMER AND DRIER. THE UPPER HIGH CENTER
DRIFTS BACK OVER NEW MEXICO...AND FAR ENOUGH WESTWARD TO PUT THE
NORTHEAST UNDER NORTHWEST FLOW AS LEAST FOR A DAY OR TWO.
.FIRE WEATHER...
BACK DOOR COLD FRONT HAS MOVED INTO THE EASTERN PLAINS WITH A
REINFORCEMENT OF THIS BOUNDARY EXPECTED FRIDAY NIGHT. CURRENTLY THE
REMNANTS OF THE UPPER LOW FROM AZ CONTINUE TO BECOME LESS ORGANIZED
OVER SOUTHERN CO. MOISTURE AND LINGERING ENERGY FROM THE LEFTOVER
DISTURBANCE WILL KEEP THE BEST WETTING RAIN CHANCES OVER NORTH
CENTRAL TO NORTHEASTERN NM TODAY. MODELS CONTINUE TO ADVERTISE DRIER
AIR WORKING IN FROM THE WEST TODAY...AND WATER VAPOR SATELLITE
IMAGERY SUPPORTS THIS. THEREFORE...EXPECT MINIMAL SHOWER/STORM
COVERAGE IN THE CENTRAL TO WEST CENTRAL AND NORTHWESTERN ZONES
TODAY. MINIMUM RH WILL STILL STAY AOA 20 PERCENT WITH MODERATE
SURFACE BREEZES EXHIBITING A NORTHWESTERLY COMPONENT OVER MUCH OF
THE FORECAST AREA. EXCELLENT RH RECOVERY IS EXPECTED OVER THE
NORTHEASTERN HALF OF THE FORECAST AREA TONIGHT WITH STILL GOOD
RECOVERY OF 60-80 PERCENT FARTHER WEST. CONVECTION FROM THE LATE
EVENING MAY ATTEMPT TO SHOVE AN EAST WIND BEYOND THE CENTRAL
MOUNTAIN CHAIN TONIGHT...BUT MODELS ARE NOT ENTHUSIASTIC ABOUT IT.
AT THIS TIME NO STRONG GAP/CANYON WINDS HAVE BEEN BUILT INTO THE
FORECAST THROUGH FRIDAY MORNING.
MOISTURE WILL HAVE AT LEAST WORKED TOWARD THE CENTRAL MOUNTAIN CHAIN
EARLY ON FRIDAY WITH THE AFOREMENTIONED EASTERLY WINDS...AND THIS
MOISTURE PUSH WILL CONTINUE WESTWARD INTO THE AFTERNOON. STORMS WILL
BECOME A BIT MORE WIDESPREAD ALONG THE CENTRAL MOUNTAIN CHAIN AND
TOWARD THE CONTINENTAL DIVIDE AS TEMPERATURES WARM CLOSE TO AVERAGE
IN MOST ZONES. LOWEST MINIMUM RH VALUES WILL BE IN THE SAN JUAN
BASIN FRIDAY WHERE VALUES WILL SLIP TO 20 PERCENT OR JUST SLIGHTLY
BELOW. ANY CONVECTION LATE FRIDAY EAST OF THE CENTRAL MOUNTAINS WILL
AID THE PUSH OF A REINFORCING BACK DOOR FRONT. THIS WILL CONTINUE TO
CARRY MOISTURE WESTWARD WHILE ALSO PRODUCING MODERATE TO STRONG
GAP/CANYON WINDS NEAR CENTRAL VALLEY LOCATIONS THROUGH SATURDAY
MORNING.
BETTER LOW LAYER MOISTURE TRANSPORTED FROM THE EAST WILL COUPLE WITH
A MID LEVEL MONSOON PLUME SQUEEZING INTO NM...AND THIS WILL SET THE
STAGE FOR AN ACTIVE THUNDERSTORM DAY SATURDAY. NAM MODEL IS MOST
BULLISH WITH WETTING PRECIP CHANCES AND CONSEQUENTLY BOASTS MUCH
COOLER TEMPERATURES WHICH WOULD CERTAINLY MITIGATE ANY FIRE WX
CONCERNS. PLENTY OF LEFTOVER MOISTURE TO RECYCLE ON SUNDAY WILL ALSO
YIELD A GOOD CROP OF STORMS. INTO NEXT WEEK THE UPPER HIGH IS STILL
DEPICTED AS MOVING WESTWARD OVER OR CLOSE TO NM WHILE ELONGATING
SOME ON A WEST-EAST AXIS. ANOTHER BACK DOOR FRONT IN THE NORTHEAST
COULD KEEP CONVECTIVE ACTIVITY GOING IN THE NORTHEAST LATE TUESDAY.
52
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
314 PM EDT THU AUG 8 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY ACROSS THE AREA WILL PROVIDE FOCUS FOR
SCATTERED SHOWERS AND THUNDERSTORMS THIS EVENING THROUGH EARLY
FRIDAY. THE FRONT WILL MOVE EAST OF THE AREA BY FRIDAY AFTERNOON
AND BRING AN END TO THE RISK OF RAIN FOR A WHILE. A MORE PRONOUNCED
COLD FRONT WILL CROSS THE AREA FRIDAY NIGHT...BUT WILL COME THROUGH
DRY WITH A COOLER AND DRIER AIRMASS FOR THE WEEKEND AS HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES.
&&
.NEAR TERM /THROUGH FRIDAY/...
THE COLD FRONT WHICH MOVED ACROSS SOUTHERN ONTARIO OVERNIGHT HAS
STALLED AND LAST MOST OF ITS THERMAL CHARACTERISTICS. THE SURFACE
TROUGH AND ASSOCIATED WIND SHIFT REMAINS ACROSS SOUTHERN ONTARIO AND
THE BASINS OF THE EASTERN GREAT LAKES. THERE IS A SURGE IN LOW LEVEL
MOISTURE TO THE EAST OF THE TROUGH...OVER WESTERN AND CENTRAL NEW
YORK...WITH DEWPOINTS RISING BACK TO THE UPPER 60S AND EVEN LOWER
70S.
ISOLATED TO SCATTERED CONVECTION WILL DEVELOP WITHIN THIS AREA OF
LOW LEVEL MOISTURE POOLING TO THE EAST OF THE SURFACE TROUGH...AIDED
BY LAKE BREEZE BOUNDARIES AND OUTFLOW BOUNDARIES FROM ADJACENT
COLLAPSING CONVECTIVE CELLS. HRRR AND LOCAL WRF MODELS IMPLY THAT
THIS DIURNAL CYCLE CONVECTION WILL FILL IN MORE AND PEAK DURING
EARLY EVENING...THEN DIMINISH SOMEWHAT...AND REGENERATE OVERNIGHT AS
THE TROUGH MOVES FARTHER TO THE EAST.
WILL MAINTAIN MID TO HIGH LIKELY POPS ACROSS MUCH OF THE FORECAST
AREA TONIGHT...WANING TO CHANCE POPS FOR THE NORTHERN NIAGARA
FRONTIER AND WESTERN TO CENTRAL LAKE ONTARIO. THE BULK OF PRECIP
WILL MOVE EAST THROUGH FRIDAY MORNING...WITH A CLEARING TREND TO
FOLLOW THROUGH THE AFTERNOON.
WE SHOULD HAVE ONE MORE MILD AND RATHER MUGGY NIGHT WITH LOWS IN THE
LOWER TO MID 60S ACROSS WESTERN NY...AND MID TO UPPER 60S FOR
CENTRAL AND NORTHERN NY. HIGHS ON FRIDAY WILL BE IN THE LOWER TO MID
70S ACROSS THE HILLS OF THE SOUTHERN TIER AND TUG HILL REGION...AND
THE MID TO UPPER 70S ELSEWHERE AIDED BY AFTERNOON SUNSHINE.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
A TRIO OF ENERGETIC SHORTWAVES WILL DROP INTO AND THROUGH AN ALREADY
ESTABLISHED HEMISPHERIC LONGWAVE TROUGH OVER EASTERN NORTH AMERICA
DURING THIS PERIOD...AND THIS WILL GUARANTEE THAT THE TROUGH WILL
REMAIN IN PLACE WHILE TEMPERATURES WILL AVERAGE BELOW NORMAL. WHILE
IT WILL BE SEASONABLY COOL...H85 TEMPS ARE NOT FORECAST TO DROP
BELOW 8C...SO ANOMALOUSLY CHILLY WEATHER IS NOT EXPECTED.
MEANWHILE AT THE SFC...EXPANSIVE HIGH PRESSURE WILL BUILD SOUTHEAST
FROM THE CANADIAN PRAIRIES ACROSS THE GREAT LAKES REGION TO THE OHIO
VALLEY. THIS WILL ENSURE MAINLY DRY WEATHER FOR THE PERIOD ALONG
WITH ABUNDANT SUNSHINE. THERE IS LITTLE ADDITIONAL DETAILED
INFORMATION TO ADD TO THIS OVERVIEW/FORECAST...BUT LETS TRY TO FILL
IN ANY REMAINING GAPS.
IN THE WAKE OF THE PASSING OF A PRIMARY COLD FRONT AND AN ENSUING
SHORTWAVE RIDGE DURING THE DAY FRIDAY...A SECONDARY COLD FRONT WILL
DROP ACROSS THE LOWER GREAT LAKES FRIDAY NIGHT. A DRY AIRMASS ABV 5K
FEET IS STILL BEING ADVERTISED BY THE GUIDANCE PACKAGES TO ACCOMPANY
THIS EVENT...SO WILL KEEP A DRY FORECAST INTACT WITH ONLY A BIT OF
LOW LEVEL CLOUD COVER.
ON SATURDAY...A LARGE CANADIAN HIGH WILL WORK ITS WAY ACROSS THE
UPPER GREAT LAKES...WHILE HELPING TO CIRCULATE COOLER AND NOTICEABLY
DRIER AIR ACROSS OUR FORECAST AREA. AFTERNOON HIGHS WILL BE IN THE
70S REGIONWIDE...BUT MORE IMPORTANTLY...DEW POINTS WILL BE SOME 10
DEG F LOWER THAN THE PREVIOUS DAY WITH READINGS IN THE LOWER 50S.
THIS SHOULD MAKE FOR A SALUBRIOUS DAY WITH AMPLE SUNSHINE TO GO
ALONG WITH THE COMFORTABLE CONDITIONS.
SATURDAY NIGHT WILL BE SOMEWHAT CHILLY AS THE SFC HIGH WILL DRIFT
CLOSE BY...RESULTING IN CLEAR SKIES AND LIGHT WINDS. OVERNIGHT LOWS
WILL RANGE FROM THE MID-UPPER 40S IN THE VALLEYS OF THE SRN TIER AND
EAST OF THE BLACK RIVER VALLEY...TO THE MID 50S ALONG THE LAKE
SHORES.
A SCINTILLATING DAY CAN THEN BE EXPECTED ON SUNDAY WITH THE CENTER
OF THE SFC HIGH DRIFTING BY TO OUR SOUTH. ONCE AGAIN...SUN FILLED
SKIES AND H85 TEMPS UNDER 10 C WILL RESULT IN A NICE DAY FOR OUTDOOR
ACTIVITIES.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE MEDIUM RANGE ENSEMBLES CONTINUE TO KEEP A DEEP LONGWAVE TROUGH
OVER THE EASTERN HALF OF NORTH AMERICA DURING THIS PERIOD. THIS WILL
FAVOR COOLER THAN AVERAGE TEMPERATURES...ALTHOUGH WE SHOULD
EXPERIENCE ONE DAY OF NEAR NORMAL READINGS AHEAD OF A REINFORCING
COLD FRONT. OUTSIDE OF RAIN FALL WITH THIS FRONTAL PASSAGE...DRY
WEATHER WILL PREVAIL.
A VIGOROUS SHORTWAVE DIVING SOUTH ACROSS WESTERN ONTARIO WILL PUSH A
COLD FRONT ACROSS THE UPPER GREAT LAKES ON MONDAY. SEASONABLY WARM
AIR WILL SURGE NORTHWARDS AHEAD OF THIS FRONT...AND THIS IN
COMBINATION WITH THE RETURN FLOW AROUND AN EXITING SFC HIGH WILL
HELP TO BOOST OUR TEMPERATURES TO NEAR 80F IN MANY AEREAS. WILL KEEP
RAIN FREE WEATHER IN PLACE FOR THE DAYLIGHT HOURS...BUT AS WE PUSH
THROUGH MONDAY NIGHT...THE FRONT IS EXPECTED TO MAKE ITS WAY ACROSS
MUCH OF OUR FORECAST AREA. THERE DOES NOT APPEAR TO BE MUCH MOISTURE
ASSOCIATED WITH THIS FRONT...SO WILL ONLY USE LOW CHC POPS AT THIS
POINT...INTRODUCING SUCH FOR MONDAY NIGHT AND EARLY TUESDAY.
AS THE ROBUST SHORTWAVE SWINGS THROUGH THE BASE OF THE TROUGH OVE
LAKE ONTARIO ON TUESDAY...THE NEXT EXPANSIVE SFC HIGH WILL SPRAWL
SOUTHWARDS ACROSS ALL OF THE GREAT LAKES REGION. THIS WILL OFFER
CLEARING SKIES FOR OUR REGION WITH ANY LEFTOVER SHOWER ACTIVITY
ENDING EARLY. H85 TEMPS ARE FORECAST DROP TO ABOUT 8C BY THE
AFTERNOON...SO IT WILL BE NOTICEABLY COOLER THAN MONDAY WITH
READINGS ONLY REACHING 70 TO 75 FOR MOST AREAS.
THE LARGE SFC HIGH WILL DRIFT ACROSS OUR FORECAST AREA WEDNESDAY AND
THURSDAY WHILE H85 TEMPS WILL REMAIN AT OR BELOW 10C. THIS WILL KEEP
FAIR DRY WEATHER IN PLACE WITH DAYTIME HIGHS GENERALLY IN THE LWOER
70S WHILE OVERNIGHT LOWS TUES AND WED NIGHTS WILL RANGE FROM THE MID
50S NEAR THE LAKES TO THE MID 40S IN THE COOLEST SRN TIER VALLEYS
AND EAST OF THE BLACK RIVER VALLEY.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
ALTHOUGH SHOWERS AND THUNDERSTORMS WILL BE LIKELY ACROSS MUCH OF THE
FORECAST AREA THIS EVENING THROUGH FRIDAY MORNING...THE MAJORITY OF
THE CONVECTION WILL BE TO THE SOUTH AND EAST OF MOST TAF SITES. THE
EXCEPTION WILL BE KJHW WHERE TSRA MAY DIRECTLY IMPACT THE SITE
THROUGH 22Z...THE EXPECT IFR CONDITIONS OVERNIGHT AFTER 08Z IN
LOCALLY DENSE FOG.
VFR CONDITIONS WILL PREVAIL ON FRIDAY AS THE WEAK SURFACE TROUGH
MOVES TO THE EAST OF THE AREA AND PARTIAL CLEARING OVERSPREADS.
OUTLOOK...
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS IN
CENTRAL NY WITH ASSOCIATED BRIEF MVFR/IFR.
SATURDAY AND SUNDAY...VFR.
MONDAY...VFR WITH CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS.
TUESDAY...VFR.
&&
.MARINE...
THE PASSAGE OF A WEAK FRONTAL ZONE WILL SHIFT WINDS TO THE NORTHWEST
OR EVEN NORTH TONIGHT AND BRING WAVES UP TO AROUND 2 FEET ON THE
SOUTH SHORE OF BOTH LAKES. WINDS WILL DIMINISH AS HIGH PRESSURE
BUILDS IN THROUGH THE WEEKEND. AS IS TYPICAL OF MID SUMMER...WINDS
AND WAVES SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH
THE WEEKEND WITH A RELATIVELY WEAK PRESSURE GRADIENT IN PLACE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WCH
NEAR TERM...WCH
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...WCH
MARINE...HITCHCOCK/WCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
152 PM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING COLD FRONT WILL EVENTUALLY MOVE PAST THE REGION ON
FRIDAY NIGHT. IN THE MEANTIME...CHANCES FOR PERIODIC SHOWERS AND
A THUNDERSTORM OR TWO WILL CONTINUE FOR TODAY AND FRIDAY. A DRIER
WEEKEND IS IN STORE WITH TEMPERATURES REMAINING ON THE COOLER SIDE
OF NORMAL FOR AUGUST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1025 AM UPDATE...
AREA OF SHOWERS AND SOME THUNDER CONTINUES TO DIMINISH. WHILE MOST
OF THE AREA WILL REMAIN DRY THROUGH EARLY AFTERNOON...SHOWERS WILL
STILL BE POSSIBLE OVER THE NORTHERN TIER OF PA AND OTSEGO/DELAWARE
COUNTIES AS THESE CONTINUE TO DIMINISH. MEANWHILE AN AREA OF
CLEARING OVER THE FINGER LAKES AND CNY MAY BE ENOUGH WITH A COLD
FRONT OVER LAKE ERIE TO PROVIDE ANOTHER CHANCE THIS AFTERNOON.
BLENDED WITH THE PREVIOUS FORECAST OF HIGH CHANCE TO LOW LIKELY
LATER TODAY...BUT I DID TRY TO SHOW A NICE GAP OF MAINLY DRY
WEATHER BETWEEN NOW AND THEN. THE PREVIOUS AFD IS BELOW...
730 AM UPDATE... QUICK UPDATE TO ACCOUNT FOR LINE OF
STORMS MVG ACRS THE AREA EARLY THIS MRNG. HV TRIED TO TRACK
CATEGORICAL POPS THRU THE REGION THRU NOON TDA. TSTMS WL TAKE
AWHILE TO REACH THE I-81 CORRIDOR IN NEPA AND MAY FALL APART BFR
THEY DO AS THEY WL BE MVG INTO INCREASINGLY STABLE AIRMASS. MLCAPE
IS 500+ JOULES WHERE THEY ARE LOCATED NOW AND FURTHER TO THE EAST
IT DIMINISHES TO NR 250 J/KG PER SPC MESOANALYSIS PAGE. HWVR THINK
THAT A GOOD CHUNK OF THE AREA BTWN I-86/I-88 AND I-80 WILL SEE
SOME FORM OF PCPN THIS MORNING AND HV BUMPED POPS TO LKLY-
CATEGORICAL TO ACCNT FOR THIS. ONCE THIS LINE OF STORMS ROLLS THRU
THINK THAT MANY PLACES WL STABILIZE FOR THE REMAINDER OF THE DAY
WITH LITTLE ELSE EXPECTED. BUT THAT WL BE LOOKED AT IN FURTHER
DETAIL FOR THE NEXT UPDATE.
PREV DISCO BLO...
TODAY WILL BE A CRAZY...CONVOLUTED AND LOW CONFIDENCE FORECAST
GIVEN THE NATURE OF ZONAL FLOW PATTERNS IN THE SUMMER MONTHS. THE
FIRST ORDER OF BUSINESS WITH THIS MORNING`S UPDATE IS TO TRACK
AND TIME THE CONVECTION MOVING THROUGH WESTERN NEW YORK AND IT`S
IMPACT HERE IN CENTRAL DURING THE EARLY HOURS. CONVECTION LOOKS TO
BE MAINLY DRIVEN NOW BY COLD POOL INTERACTION WITHIN A BROAD
UNSTABLE ENVIRONMENT...AS WV LOOP SHOWS INITIATING SHORT WAVE IS
RUNNING OUT AHEAD OF THE CONVECTION ACROSS LOWER ONTARIO. LINEAR
TRACKING TAKES THE RAIN AND EMBEDDED TSRA ACROSS MAINLY THE FINGER
LAKES REGION AND NORTHERN PORTIONS OF THE SOUTHERN TIER DURING THE
EARLY DAYLIGHT HOURS AND HAVE ACCOUNTED FOR THIS WITH ABOUT 4-6
HOURS OF CATEGORICAL-LIKELY POPS OVER NORTHERN COUNTIES WITH SOME
SLACK ON THE SOUTHERN END OF THE POP FIELD FOR NEW DEVELOPMENT.
THINK THERE WILL ALSO CONTINUE TO BE WEAKENING OF THIS FEATURE AS
THE MORNING WEARS ON.
THEN...ATTENTION TURNS TO SLOWLY APPROACHING FRONTAL BOUNDARY FOR
LATER THIS AFTERNOON. AFTER SCOURING MANY MODEL SOLUTIONS...AND
PICKING THROUGH THE NOISE OF CONVECTIVE FEEDBACK...WE ARE HARD
PRESSED TO FIND MUCH IN THE WAY OF FORCING FOR NEW CONVECTION THIS
AFTERNOON ASIDE FROM MINOR HEIGHT AND PRESSURE FALLS ASSOCIATED
WITH THE FRONTAL BOUNDARY...FORMING IN TANDEM WITH DECREASING
DIURNAL STABILITY. THE MESOSCALE MODELS LIKE THE HRRR AND WRF-ARW
CONVECT MAINLY ALONG THE FRONTAL BOUNDARY MOVING INTO WRN NY THIS
AFTERNOON WITH SPOTTY ACTIVITY IN OUR AREA. WE THEREFORE FEEL MUCH
OF THE DAY WILL FEATURE...AT BEST... SCATTERED NEW CONVECTIVE
DEVELOPMENT ONCE THIS LINGERING RAIN FEATURE MAKES ITS WAY THROUGH
OR DISSIPATES IN THE PROCESS. HAVE THUS SCALED BACK ON ANY LIKELY
POPS WE HAD GOING THIS AFTERNOON.
OTHER PARAMETERS ARE FAIRLY ROUTINE. TEMPERATURES AS A BLEND OF
PREV FORECAST/00Z MOS AND 2M MODEL TEMPS AND LOOK TO BE MAINLY IN
THE UPPER 70S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
THE FORECAST GETS NO EASIER TONIGHT WITH FRONT ONLY SAGGING INTO
THE REGION. 00Z NAM AND GFS ARE SIMILAR IN FRONTAL PLACEMENT AND
UPPER AIR MASS FIELDS...BUT THE RESULTANT QPF FIELDS ARE VERY
DIFFERENT TONIGHT AND FRIDAY AND SEEM OVERDONE WITH RESPECT TO
VERY SUBTLE FORCING MECHANISMS. AGAIN...WEEDING THROUGH THE
CONVECTIVE FEEDBACK PROBLEMS AS BOTH MODELS TRY TO LIFT SOUTHERN
PLAINS CONVECTIVE VORTS THROUGH OUR REGION OVERNIGHT...WE ARE
AGAIN HARD PRESSED TO FIND SIGNIFICANT SYNOPTIC SUPPORT FOR AS
MUCH RAIN AS THESE MODELS ARE CRANKING OUT ON US. THAT SAID...THE
SFC FRONT WILL BE MOVING INTO THE REGION AND THERE IS A
POSSIBILITY THAT SOME MINOR UPPER LEVEL FEATURE COULD RUN FAST
THROUGH THE REGION. BOTH MODELS ALSO HINT AT AN INCRG SOUTHERLY
LOW LEVEL JET IMPINGING ON THE FRONTAL ZONE AND OUR HIGHER TERRAIN
AREAS IN NEPA/SENY LATE TONIGHT. WITHOUT MAKING TOO DRAMATIC A
SWING IN THE FORECAST...HAVE LOWERED SOME OF THE PREVIOUS FORECAST
POPS FOR TONIGHT AND FRIDAY...BUT HAVE MAINTAINED THE LIKELY
TERMINOLOGY AS THERE JUST DOESN`T SEEM TO BE MUCH THERE TO WARRANT
WIDESPREAD AREAS OF SHOWERS/TSRA. ALSO SHIFTED THE AXIS OF HIGHER
POPS A BIT WESTWARD TO LINE UP BETTER WITH THE FRONTAL MOVEMENT.
THE FOCUS ON THE SOUTHEAST ZONES JUST SEEMS UNREALISTIC AND THE
GFS SEEMED TO HAVE TRENDED A BIT WEST THIS RUN WITH NAM MORE IN
OUR EASTERN ZONES.
THE TRENDS THEN SUPPORT THE FRONT TO MOVE EAST OF THE REGION
FRIDAY NIGHT WITH DECREASING PRECIP PROBABILITY FROM WEST TO EAST
THROUGH THE DAY FRIDAY AND EVENTUALLY A DRY OVERNIGHT INTO SATURDAY.
HIGH PRESSURE AND COOL NORTHWESTERLY FLOW OVERSPREADS THE REGION
THIS WEEKEND. BEST CHANCE FOR SUNSHINE LOOKS TO BE SUNDAY AS COLD
ADVECTION CLOUDS ON THE FIRST DAY (SATURDAY) BEHIND A COLD FROPA
HERE SPELLS STRATOCU FIELDS GALORE AND PARTLY TO MOSTLY CLOUDY
CONDITIONS.
FOLLOWED MOS AND 2M MODEL BLENDED TEMPS ALONG WITH PREVIOUS
FORECAST WHICH HELPED TO COOL THINGS SLIGHTLY ON FRIDAY AND
SATURDAY FROM PREV FORECAST. THE TREND ON SATURDAY WILL CERTAINLY
FIT THE CLOUD IDEA.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
2 PM UPDATE...
MED RANGE MODELS IN FAIR AGREEMENT THRU THE LONG TERM. MODELS
ADVERTISING FROPA BEGINNING MON NGT AND THRU MOST OF THE AREA ON
TUESDAY, THUS HV POPS FOR THIS TIME PD. SHOWERS AND TSTMS EXPECTED
DRG THE AFTN HRS. 1020MB SFC HIGH WL BUILD IN AND LV DRY WX THRU
THE REST OF THE PD. TEMPS WL BE RUNNING BLO NORMAL THRU MID-WEEK.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z UPDATE...
CIGS ARE MVFR/VFR AT THIS TIME AHEAD OF CDFNT THAT IS SAGGING
SOUTH TOWARD THE AREA. SHOWERS AND THUNDERSTORMS WILL DEVELOP
BETWEEN 20Z AND 24Z THUS HAVE TEMPO/D IN MVFR RESTRICTIONS. AFTER
THIS TIME ANY PRECIPITATION THAT DEVELOPS WILL BE AT RANDOM THUS
HAVE NOT INCLUDED IN TERMINAL FORECASTS AT THIS TIME. CIGS WILL
LOWER AFTER 06Z AT KSYR/KRME/KELM, AFTER 04Z AT HIGHER ELEVATION
TERMINALS OF KITH/KBGM. WITH MARINE LAYER EXPECTED TO MOVE BACK IN
KAVP WILL BE THE FIRST SITE TO SEE MVFR RESTRICTIONS AT 02Z.
POTENTIAL FOR IFR WILL EXIST AT KITH AND KBGM BETWEEN 08Z AND 12Z.
FRONTAL PASSAGE EXPECTED TO OCCUR AT NY TERMINALS AROUND 15Z WITH
MVFR CIGS HANGING AROUND THROUGH 18Z FRIDAY.
WINDS OUT OF THE SOUTH AROUND 5KTS WILL BECOME LIGHT OVERNIGHT
THEN SWITCH AROUND TO NORTHWEST AFTER 15Z FRIDAY.
OUTLOOK...
FRI...VFR BUT MVFR IN SCATTERED SHRA/TSRA MAINLY SOUTH.
SAT THRU MON...VFR.
MON NGT/TUE...MVFR RESTRICTION IN SHRA/TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...JAB
NEAR TERM...HEDEN/JAB/PVN
SHORT TERM...JAB
LONG TERM...PVN
AVIATION...PVN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
321 PM EDT THU AUG 8 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE ANCHORED OFFSHORE WILL RESULT IN A MOIST
SOUTHERLY FLOW ACROSS THE CAROLINAS THROUGH FRIDAY. A WEAK COLD
FRONT WILL APPROACH THE REGION FROM THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM THURSDAY...
A WEAK WEST-EAST OR WSW-ENE ORIENTED UPPER LEVEL RIDGE ACROSS THE
SOUTH-CENTRAL AND SOUTHEAST CONUS WILL REMAIN IN PLACE THROUGH
TONIGHT...WITH THE PRIMARY BELT OF WESTERLIES LOCATED ACROSS THE
NORTHERN TIER OF THE CONUS (I.E. GREAT LAKES). WEAK WSW FLOW ALOFT
WILL PREVAIL ACROSS THE CAROLINAS. SOUTHERLY LOW-LEVEL RETURN FLOW
WILL PERSIST ACROSS THE REGION...ON THE WESTERN PERIPHERY OF A BROAD
SFC-H85 RIDGE CENTERED OFFSHORE IN THE ATLANTIC. LOW-LEVEL FLOW IS
PROGGED TO STRENGTHEN FROM 5-10 KT EARLY THIS AFTERNOON TO 15-25 KT
TONIGHT AS A POTENT UPPER LEVEL LOW IN ONTARIO PROGRESSES EAST
TOWARD QUEBEC AND AN ATTENDANT LOW-LEVEL TROUGH PROGRESSES INTO THE
OH VALLEY AND MID-ATLANTIC.
THIS AFTERNOON THROUGH MIDNIGHT:
ISOLD SHOWERS DEVELOPED IN THE FOOTHILLS AND FAR WESTERN PIEDMONT
THIS MORNING AND HAVE PERSISTED THROUGH EARLY THIS AFTERNOON. THIS
ACTIVITY IS ASSOCIATED WITH WEAK H85 CONFLUENCE IN THE PRESENCE OF
MARGINAL DIURNAL DESTABILIZATION AND DEEP MOISTURE (PWAT ~2.00").
THIS ACTIVITY MAY ALSO BE AIDED BY A VERY SUBTLE SMALL AMPLITUDE
DISTURBANCE EMBEDDED WITHIN WEAK WSW FLOW ALOFT OVER UPSTATE SC AND
SOUTHWEST NC. RAP GUIDANCE SUGGESTS THAT THE ZONE OF WEAK H85
CONFLUENCE ACTING AS A FOCUS WILL SHIFT EAST OF THE I-77 CORRIDOR
INTO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE...AND PROBABILITIES
FOR ISOLD TO SCT SHOWER ACTIVITY SHOULD ACCORDINGLY INCREASE
(40-50%) IN THE TRIAD AND W/SW PIEDMONT. ACTIVITY SHOULD PEAK IN
COVERAGE/INTENSITY BETWEEN 20-00Z WHEN DIURNAL DESTABILIZATION WILL
BE MAXIMIZED WITH MLCAPE VALUES OF 500-1000 J/KG...FOLLOWED BY
DECREASING COVERAGE/ INTENSITY THEREAFTER IN ASSOC/W THE ONSET OF
NOCTURNAL STABILIZATION. AN ISOLD THUNDERSTORM CANNOT BE RULED
OUT...THOUGH MARGINAL MLCAPE...WEAK MID-LEVEL LAPSE RATES AND WEAK
OVERALL FORCING MAY ULTIMATELY SERVE AS A LIMITING FACTOR W/REGARD
TO LIGHTNING. ALONG AND EAST OF THE HWY 1 CORRIDOR...STRONGER
INSOLATION WILL RESULT IN BETTER INSTABILITY WITH MLCAPE VALUES OF
1000-1500 J/KG EXPECTED. ALTHOUGH A WHOLESALE LACK OF FORCING MAY
LARGELY PRECLUDE CONVECTIVE DEVELOPMENT ALONG/EAST OF HWY 1...DEEP
MOISTURE...SEASONABLE DIURNAL DESTABILIZATION AND LITTLE OR NO CIN
SHOULD AT LEAST ALLOW FOR VERY ISOLD DEVELOPMENT...AND WILL INDICATE
A SLIGHT CHANCE (20%) OF SHOWERS IN THAT AREA PRIOR TO SUNSET.
OUTSIDE OF SOUTHERN SAMPSON COUNTY...ANTICIPATE LITTLE INFLUENCE
FROM THE SEABREEZE GIVEN LOW-LEVEL FLOW BECOMING INCREASINGLY
PARALLEL TO THE COAST THIS AFT/EVE. EXPECT HIGHS TODAY RANGING FROM
87-91F ALONG/EAST OF HWY 1 TO 82-85F IN THE WESTERN PIEDMONT WHERE
MORE CLOUD COVER IS PRESENT AND ISOLD SHOWER ACTIVITY MORE LIKELY.
MIDNIGHT THROUGH SUNRISE FRI:
FORCING FOR ASCENT WILL LARGELY BE ABSENT OVERNIGHT GIVEN WEAK FLOW
ALOFT...UNIDIRECTIONAL (SW) LOW-LEVEL FLOW AND LITTLE OR NO WARM
ADVECTION. A FEW ISOLD SHOWERS OR SPRINKLES CANNOT BE RULED OUT
GIVEN SUCH DEEP MOISTURE (PWAT ~2.00")...MARGINAL MUCAPE ASSOC/W A
925 MB AIRMASS CHARACTERIZED BY A T/TD OF 22/19C AND A SMALL
POTENTIAL FOR SUBTLE DISTURBANCES ALOFT OR WEAK LOW-LEVEL
CONVERGENCE...PRIMARILY IN THE W/NW PIEDMONT. WILL INDICATE A SLIGHT
CHANCE OF SHOWERS IN THE TRIAD AND FAR WESTERN PIEDMONT. EXPECT
RELATIVELY WARM LOWS IN THE LOWER 70S. -VINCENT
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 315 PM THURSDAY...
WEAK RIDGING ALOFT WILL PERSIST ACROSS THE SOUTH-CENTRAL AND
SOUTHEAST CONUS FRI/FRI NIGHT...WITH THE PRIMARY BELT OF WESTERLIES
CONFINED TO THE FAR NORTHERN MID-ATLANTIC...GREAT LAKES...AND NEW
ENGLAND. DEEP MOISTURE WILL PERSIST OVER THE CAROLINAS WITH PWAT
VALUES IN VICINITY OF 2.00"...AND DIURNAL DESTABILIZATION WILL BE
SOMEWHAT TEMPERED BY THE EXPECTATION OF OCCASIONALLY BROKEN CLOUD
COVER AND VERY WEAK (NEAR MOIST-ADIABATIC) MID-LEVEL LAPSE RATES...
WITH MLCAPE VALUES GENERALLY 750-1500 J/KG...THOUGH 1500-2000 J/KG
WILL BE POSSIBLE IF INSOLATION REMAINS UNINHIBITED IN SOME AREAS.
LITTLE IF ANY DIRECT UPPER LEVEL FORCING WILL BE PRESENT OVER
CENTRAL NC ON FRI/FRI NIGHT GIVEN THAT THE REGION IS AT THE FAR
SOUTHERN FRINGE OF THE WESTERLIES. HOWEVER...AN UPPER LEVEL LOW OVER
ONTARIO THIS AFTERNOON WILL TRACK EAST INTO QUEBEC TONIGHT/FRI...AND
AN ATTENDANT LOW-LEVEL TROUGH /SFC COLD FRONT/ WILL PUSH EAST FROM
THE GREAT LAKES INTO NEW ENGLAND AND THE NORTHERN MID-ATLANTIC. AN
EXTENSION OF THIS LOW-LEVEL TROUGH IS EXPECTED TO STRETCH SOUTHWEST
INTO WEST/NW PORTIONS OF THE CAROLINAS LATE FRIDAY AFT/EVE AND
FRIDAY NIGHT...AND THIS WILL LIKELY SERVE AS AN EFFECTIVE FOCUS FOR
CONVECTIVE DEVELOPMENT GIVEN EXCELLENT DEEP-LAYER MOISTURE...
MODERATE INSTABILITY AROUND/SHORTLY AFTER PEAK HEATING AND AT LEAST
MARGINAL INSTABILITY PERSISTING OVERNIGHT. ANTICIPATE THAT THE
SEABREEZE WILL REMAIN PINNED SOUTHEAST OF CUMBERLAND/SAMPSON/WAYNE
COUNTIES FRIDAY AFT/EVE GIVEN 15-20 KT SW/WSW LOW-LEVEL FLOW THAT
WILL BE NEAR PARALLEL TO THE NC COAST...ESPECIALLY GIVEN HIGHS AT
LEAST SOMEWHAT TEMPERED BY CLOUD COVER AND A RESULTING WEAKER
LAND/WATER TEMPERATURE GRADIENT. WITH THE ABOVE IN MIND...WILL
INDICATE PRECIP CHANCES RANGING FROM 40-60% WEST OF HWY 1 FRIDAY
AFTERNOON THROUGH MIDNIGHT...AND SLIGHT TO LOW CHANCE (20-40%) EAST
OF HWY 1...LOWEST EAST OF I-95 AND SOUTH OF HWY 64. WILL INDICATE A
SLIGHT TO LOW CHANCE (20-30%) OF CONVECTION PERSISTING OVERNIGHT
GIVEN CONTINUED (ALBEIT WEAK) LOW-LEVEL CONVERGENCE...DEEP
MOISTURE...AND MARGINAL INSTABILITY...PRIMARILY ALONG AND NORTH OF
HWY 64 AS THE LOW-LEVEL TROUGH BECOMES INCREASINGLY WEST-EAST
ORIENTED AND APPROACHES THE NC/VA BORDER FROM THE NORTH. HIGHS
FRIDAY RANGING FROM THE MID/UPPER 80S TO LOWER 90S...DEPENDENT
PRIMARILY ON CLOUD COVER. LOWS FRI NIGHT LOWER/MID 70S. -VINCENT
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...
THIS WEEKEND...SURFACE HIGH OFFSHORE FLATTENS AND ALIGNS MORE
EAST-WEST ACROSS THE SOUTHERN GULF STATES. ENSUING WESTERLY FLOW
WILL SHARPEN LEE TROUGHING OVER CENTRAL NC...INTO WHICH A WEAK COLD
FRONT SAGGING SOUTH OUT OF THE OHIO VALLEY WILL MERGE SATURDAY
NIGHT. MEANWHILE...FLOW WILL REMAIN WEAK AND NEAR ZONAL ALOFT. LOW
LEVEL FORCING FROM THE TWO BOUNDARIES WILL BE SUFFICIENT FOR
DEVELOPMENT OF FAIRLY WIDESPREAD CONVECTION IN THE LATE DAY AS HIGHS
WILL BE WITHIN A COUPLE OF DEGREES EITHER SIDE OF 90. EXPECT THE
FRONT DROPPING SOUTH TO BE THE STRONGER OF THE TWO AND WILL HAVE
LIKELY POPS ACROSS THE NORTH TO CHANCE IN THE SOUTH.
WE WILL HAVE A CONTINUING CHANCE OF SHOWERS OVERNIGHT SATURDAY NIGHT
AS THE BOUNDARIES MERGE...WHILE SUNDAY SHOULD BE QUITE ACTIVE
CONVECTIVELY...50 POP NORTHWEST TO 70 SOUTHEAST...ESPECIALLY ACROSS
THE SOUTHERN TIER WHERE MODELS HINT THAT WE COULD SEE A WEAK SURFACE
WAVE DEVELOP ALONG THE FRONT. NOT SEEING MUCH COOL AIR ADVECTION OR
HEIGHT FALLS SUNDAY...BUT HEAVY CLOUDINESS AND PRECIP WILL HAMPER
THE DIURNAL CLIMB...WITH HIGHS IN THE MID AND UPPER 80S. -MLM
ON MONDAY MOSTLY ZONAL FLOW OVER THE EASTERN US WILL YIELD TO A
TROUGH DIGGING SOUTHWARD FROM NORTHERN ONTARIO. THIS TROUGH WILL
DOMINATE THE SENSIBLE WEATHER THROUGH MIDWEEK...WITH LOWER THAN
NORMAL HIGH TEMPERATURES AND AN ABOVE NORMAL CHANCE OF RAIN.
AN INITIAL STATIONARY SURFACE FRONT OVER CENTRAL NC ON MONDAY WILL
BE PUSHED TO THE SE BY A SECOND APPROACHING SURFACE FRONT ASSOCIATED
WITH THE DIGGING TROUGH AROUND TUESDAY NIGHT. BOTH GFS AND EURO
MODELS SHOW THIS GREAT LAKES TROUGH AXIS AMPLIFYING SOUTHWARD INTO
KY AND TN BY EARLY TUESDAY. THESE MODELS HAVE SOME DISAGREEMENT IN
HOW QUICKLY THIS TROUGH MIGRATES EASTWARD. THE EASTWARD TROUGH
MOVEMENT WILL DETERMINE WHEN AND WHERE THIS SECOND SURFACE FRONT
WILL SET UP OVER CENTRAL NC. BOTH THE EURO AND GFS PREDICT THIS
FRONT TO BECOME ZONALLY ORIENTED...THE GFS EXPECTS THE FRONT TO
STALL OUT AND REMAIN STATIONARY OVER CENTRAL NC THROUGH WEDNESDAY
AND THURSDAY AS SURFACE HIGH PRESSURE BUILDS TO THE NORTH...WHILE
THE EURO HAS THE FRONT SLOWLY PASS THROUGH CENTRAL NC THROUGH
TUESDAY AND TUESDAY NIGHT BEFORE STALLING OUT MUCH FARTHER TO THE
SOUTH ON THURSDAY MORNING. THE LOCATION OF THIS FRONT WILL HIGHLY
IMPACT WHERE THE GREATEST PRECIP CHANCES WILL BE...WHILE THE SURFACE
HIGH AND ASSOCIATED DRY AIR WILL PUSH HIGH TEMPERATURES TO BE LOWER
INTO THE MIDWEEK.
THEREFORE...WILL PREDICT AN ABOVE NORMAL CHANCE OF POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY ASSOCIATED WITH THE INITIAL
FRONT...FOR WEDNESDAY AND THURSDAY...WITH MODEL AGREEMENT THAT THE
SECOND FRONT WILL BE OVER CENTRAL NC...HIGHER POPS TO THE SE AS
DRIER AIR IS EXPECTED TO BUILD BEHIND THE FRONT TO THE FAR NW OF THE
FORECAST AREA. HIGHS UPPER 80S-LOW 90S FOR MONDAY, COOLING TO THE
MID 80S FOR TUESDAY AND WEDNESDAY BEFORE MAINLY LOWER 80S ON
THURSDAY. LOWS NEAR PERSISTENCE ON MONDAY NIGHT...UPPER 60S AND LOW
70S...DECREASING TO THE MID AND UPPER 60S FOR TUESDAY AND WEDNESDAY
NIGHT. -BAS
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM THURSDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL LARGELY PREVAIL THIS AFTERNOON THROUGH 06Z
TONIGHT. THE EXCEPTION WILL BE AT THE INT/GSO TERMINALS WHERE
PERIODIC MVFR CEILINGS AND PERHAPS ISOLD SHOWER ACTIVITY WILL BE
POSSIBLE THROUGH 00-03Z THIS EVENING. OVERNIGHT...MVFR/IFR CEILINGS
WILL BE POSSIBLE AT ALL TERMINALS...THOUGH CONFIDENCE IS RELATIVELY
LOW W/REGARD TO THE TIMING AND COVERAGE OF SUB-VFR CEILINGS ASSOC/W
WITH POTENTIAL STRATUS DEVELOPMENT IN THE 08-14Z TIME FRAME.
MVFR/IFR VISBYS IN FOG WILL ALSO BE POSSIBLE BETWEEN 08-12Z AT THE
FAY/RWI TERMINALS (SIMILAR TO PREVIOUS NIGHTS)...THOUGH THIS WILL
DEPEND ON CLOUD COVER. A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS
IS EXPECTED FRIDAY AFTERNOON AS A LOW-LEVEL TROUGH DEVELOPS IN THE
LEE OF THE APPALACHIANS.
LOOKING AHEAD:
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM..VINCENT
LONG TERM...MLM/BAS
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
226 PM EDT THU AUG 8 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE ANCHORED OFFSHORE WILL RESULT IN A MOIST
SOUTHERLY FLOW ACROSS THE CAROLINAS THROUGH FRIDAY. A WEAK COLD
FRONT WILL APPROACH THE REGION FROM THE NORTH OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM THURSDAY...
A WEAK WEST-EAST OR WSW-ENE ORIENTED UPPER LEVEL RIDGE ACROSS THE
SOUTH-CENTRAL AND SOUTHEAST CONUS WILL REMAIN IN PLACE THROUGH
TONIGHT...WITH THE PRIMARY BELT OF WESTERLIES LOCATED ACROSS THE
NORTHERN TIER OF THE CONUS (I.E. GREAT LAKES). WEAK WSW FLOW ALOFT
WILL PREVAIL ACROSS THE CAROLINAS. SOUTHERLY LOW-LEVEL RETURN FLOW
WILL PERSIST ACROSS THE REGION...ON THE WESTERN PERIPHERY OF A BROAD
SFC-H85 RIDGE CENTERED OFFSHORE IN THE ATLANTIC. LOW-LEVEL FLOW IS
PROGGED TO STRENGTHEN FROM 5-10 KT EARLY THIS AFTERNOON TO 15-25 KT
TONIGHT AS A POTENT UPPER LEVEL LOW IN ONTARIO PROGRESSES EAST
TOWARD QUEBEC AND AN ATTENDANT LOW-LEVEL TROUGH PROGRESSES INTO THE
OH VALLEY AND MID-ATLANTIC.
THIS AFTERNOON THROUGH MIDNIGHT:
ISOLD SHOWERS DEVELOPED IN THE FOOTHILLS AND FAR WESTERN PIEDMONT
THIS MORNING AND HAVE PERSISTED THROUGH EARLY THIS AFTERNOON. THIS
ACTIVITY IS ASSOCIATED WITH WEAK H85 CONFLUENCE IN THE PRESENCE OF
MARGINAL DIURNAL DESTABILIZATION AND DEEP MOISTURE (PWAT ~2.00").
THIS ACTIVITY MAY ALSO BE AIDED BY A VERY SUBTLE SMALL AMPLITUDE
DISTURBANCE EMBEDDED WITHIN WEAK WSW FLOW ALOFT OVER UPSTATE SC AND
SOUTHWEST NC. RAP GUIDANCE SUGGESTS THAT THE ZONE OF WEAK H85
CONFLUENCE ACTING AS A FOCUS WILL SHIFT EAST OF THE I-77 CORRIDOR
INTO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE...AND PROBABILITIES
FOR ISOLD TO SCT SHOWER ACTIVITY SHOULD ACCORDINGLY INCREASE
(40-50%) IN THE TRIAD AND W/SW PIEDMONT. ACTIVITY SHOULD PEAK IN
COVERAGE/INTENSITY BETWEEN 20-00Z WHEN DIURNAL DESTABILIZATION WILL
BE MAXIMIZED WITH MLCAPE VALUES OF 500-1000 J/KG...FOLLOWED BY
DECREASING COVERAGE/ INTENSITY THEREAFTER IN ASSOC/W THE ONSET OF
NOCTURNAL STABILIZATION. AN ISOLD THUNDERSTORM CANNOT BE RULED
OUT...THOUGH MARGINAL MLCAPE...WEAK MID-LEVEL LAPSE RATES AND WEAK
OVERALL FORCING MAY ULTIMATELY SERVE AS A LIMITING FACTOR W/REGARD
TO LIGHTNING. ALONG AND EAST OF THE HWY 1 CORRIDOR...STRONGER
INSOLATION WILL RESULT IN BETTER INSTABILITY WITH MLCAPE VALUES OF
1000-1500 J/KG EXPECTED. ALTHOUGH A WHOLESALE LACK OF FORCING MAY
LARGELY PRECLUDE CONVECTIVE DEVELOPMENT ALONG/EAST OF HWY 1...DEEP
MOISTURE...SEASONABLE DIURNAL DESTABILIZATION AND LITTLE OR NO CIN
SHOULD AT LEAST ALLOW FOR VERY ISOLD DEVELOPMENT...AND WILL INDICATE
A SLIGHT CHANCE (20%) OF SHOWERS IN THAT AREA PRIOR TO SUNSET.
OUTSIDE OF SOUTHERN SAMPSON COUNTY...ANTICIPATE LITTLE INFLUENCE
FROM THE SEABREEZE GIVEN LOW-LEVEL FLOW BECOMING INCREASINGLY
PARALLEL TO THE COAST THIS AFT/EVE. EXPECT HIGHS TODAY RANGING FROM
87-91F ALONG/EAST OF HWY 1 TO 82-85F IN THE WESTERN PIEDMONT WHERE
MORE CLOUD COVER IS PRESENT AND ISOLD SHOWER ACTIVITY MORE LIKELY.
MIDNIGHT THROUGH SUNRISE FRI:
FORCING FOR ASCENT WILL LARGELY BE ABSENT OVERNIGHT GIVEN WEAK FLOW
ALOFT...UNIDIRECTIONAL (SW) LOW-LEVEL FLOW AND LITTLE OR NO WARM
ADVECTION. A FEW ISOLD SHOWERS OR SPRINKLES CANNOT BE RULED OUT
GIVEN SUCH DEEP MOISTURE (PWAT ~2.00")...MARGINAL MUCAPE ASSOC/W A
925 MB AIRMASS CHARACTERIZED BY A T/TD OF 22/19C AND A SMALL
POTENTIAL FOR SUBTLE DISTURBANCES ALOFT OR WEAK LOW-LEVEL
CONVERGENCE...PRIMARILY IN THE W/NW PIEDMONT. WILL INDICATE A SLIGHT
CHANCE OF SHOWERS IN THE TRIAD AND FAR WESTERN PIEDMONT. EXPECT
RELATIVELY WARM LOWS IN THE LOWER 70S. -VINCENT
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
AS OF 250 AM THURSDAY...
FRIDAY/FRIDAY NIGHT...
THE COLD FRONT OVER THE MIDWEST WILL MOVE VERY SLOWLY INTO THE OHIO
VALLEY REGION BY FRIDAY AS IT RUNS INTO A MODEST RIDGE OVER THE
SOUTHEAST US. AHEAD OF THE FRONT...LOW-LEVEL TRAJECTORIES WILL
BECOME MORE SOUTHWESTERLY WITH SIGNS OF A PREFRONTAL/LEE TROUGH
BEGINNING TO DEVELOP. PW WILL BE QUITE HIGH (ABOVE 2 INCHES) AND
INSTABILITY SLIGHTLY HIGHER THAN THE PAST COUPLE OF DAYS (AROUND
1000 J/KG). THUS...CHANCE POPS WILL BE INCLUDED ACROSS THE ENTIRE
CWA...THOUGH COVERAGE IS LIKELY TO BE GREATEST IN THE WEST. DEEP
SHEAR WILL CONTINUE T BE WEAK...SO THE MAIN THREAT WILL BE HEAVY
RAINS FROM SLOW MOVING STORMS. HIGHS RIGHT AROUND NORMAL...87-91. A
FEW SHOWERS AND STORMS MAY BE POSSIBLE ACROSS THE NORTH FRIDAY NIGHT
AS THE 850MB TROUGH DROPS SOUTH INTO VIRGINIA. LOWS IN THE LOWER
70S. -SMITH
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...
THIS WEEKEND...SURFACE HIGH OFFSHORE FLATTENS AND ALIGNS MORE
EAST-WEST ACROSS THE SOUTHERN GULF STATES. ENSUING WESTERLY FLOW
WILL SHARPEN LEE TROUGHING OVER CENTRAL NC...INTO WHICH A WEAK COLD
FRONT SAGGING SOUTH OUT OF THE OHIO VALLEY WILL MERGE SATURDAY
NIGHT. MEANWHILE...FLOW WILL REMAIN WEAK AND NEAR ZONAL ALOFT. LOW
LEVEL FORCING FROM THE TWO BOUNDARIES WILL BE SUFFICIENT FOR
DEVELOPMENT OF FAIRLY WIDESPREAD CONVECTION IN THE LATE DAY AS HIGHS
WILL BE WITHIN A COUPLE OF DEGREES EITHER SIDE OF 90. EXPECT THE
FRONT DROPPING SOUTH TO BE THE STRONGER OF THE TWO AND WILL HAVE
LIKELY POPS ACROSS THE NORTH TO CHANCE IN THE SOUTH.
WE WILL HAVE A CONTINUING CHANCE OF SHOWERS OVERNIGHT SATURDAY NIGHT
AS THE BOUNDARIES MERGE...WHILE SUNDAY SHOULD BE QUITE ACTIVE
CONVECTIVELY...50 POP NORTHWEST TO 70 SOUTHEAST...ESPECIALLY ACROSS
THE SOUTHERN TIER WHERE MODELS HINT THAT WE COULD SEE A WEAK SURFACE
WAVE DEVELOP ALONG THE FRONT. NOT SEEING MUCH COOL AIR ADVECTION OR
HEIGHT FALLS SUNDAY...BUT HEAVY CLOUDINESS AND PRECIP WILL HAMPER
THE DIURNAL CLIMB...WITH HIGHS IN THE MID AND UPPER 80S. -MLM
ON MONDAY MOSTLY ZONAL FLOW OVER THE EASTERN US WILL YIELD TO A
TROUGH DIGGING SOUTHWARD FROM NORTHERN ONTARIO. THIS TROUGH WILL
DOMINATE THE SENSIBLE WEATHER THROUGH MIDWEEK...WITH LOWER THAN
NORMAL HIGH TEMPERATURES AND AN ABOVE NORMAL CHANCE OF RAIN.
AN INITIAL STATIONARY SURFACE FRONT OVER CENTRAL NC ON MONDAY WILL
BE PUSHED TO THE SE BY A SECOND APPROACHING SURFACE FRONT ASSOCIATED
WITH THE DIGGING TROUGH AROUND TUESDAY NIGHT. BOTH GFS AND EURO
MODELS SHOW THIS GREAT LAKES TROUGH AXIS AMPLIFYING SOUTHWARD INTO
KY AND TN BY EARLY TUESDAY. THESE MODELS HAVE SOME DISAGREEMENT IN
HOW QUICKLY THIS TROUGH MIGRATES EASTWARD. THE EASTWARD TROUGH
MOVEMENT WILL DETERMINE WHEN AND WHERE THIS SECOND SURFACE FRONT
WILL SET UP OVER CENTRAL NC. BOTH THE EURO AND GFS PREDICT THIS
FRONT TO BECOME ZONALLY ORIENTED...THE GFS EXPECTS THE FRONT TO
STALL OUT AND REMAIN STATIONARY OVER CENTRAL NC THROUGH WEDNESDAY
AND THURSDAY AS SURFACE HIGH PRESSURE BUILDS TO THE NORTH...WHILE
THE EURO HAS THE FRONT SLOWLY PASS THROUGH CENTRAL NC THROUGH
TUESDAY AND TUESDAY NIGHT BEFORE STALLING OUT MUCH FARTHER TO THE
SOUTH ON THURSDAY MORNING. THE LOCATION OF THIS FRONT WILL HIGHLY
IMPACT WHERE THE GREATEST PRECIP CHANCES WILL BE...WHILE THE SURFACE
HIGH AND ASSOCIATED DRY AIR WILL PUSH HIGH TEMPERATURES TO BE LOWER
INTO THE MIDWEEK.
THEREFORE...WILL PREDICT AN ABOVE NORMAL CHANCE OF POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY ASSOCIATED WITH THE INITIAL
FRONT...FOR WEDNESDAY AND THURSDAY...WITH MODEL AGREEMENT THAT THE
SECOND FRONT WILL BE OVER CENTRAL NC...HIGHER POPS TO THE SE AS
DRIER AIR IS EXPECTED TO BUILD BEHIND THE FRONT TO THE FAR NW OF THE
FORECAST AREA. HIGHS UPPER 80S-LOW 90S FOR MONDAY, COOLING TO THE
MID 80S FOR TUESDAY AND WEDNESDAY BEFORE MAINLY LOWER 80S ON
THURSDAY. LOWS NEAR PERSISTENCE ON MONDAY NIGHT...UPPER 60S AND LOW
70S...DECREASING TO THE MID AND UPPER 60S FOR TUESDAY AND WEDNESDAY
NIGHT. -BAS
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 200 PM THURSDAY...
24-HR TAF PERIOD:
VFR CONDITIONS WILL LARGELY PREVAIL THIS AFTERNOON THROUGH 06Z
TONIGHT. THE EXCEPTION WILL BE AT THE INT/GSO TERMINALS WHERE
PERIODIC MVFR CEILINGS AND PERHAPS ISOLD SHOWER ACTIVITY WILL BE
POSSIBLE THROUGH 00-03Z THIS EVENING. OVERNIGHT...MVFR/IFR CEILINGS
WILL BE POSSIBLE AT ALL TERMINALS...THOUGH CONFIDENCE IS RELATIVELY
LOW W/REGARD TO THE TIMING AND COVERAGE OF SUB-VFR CEILINGS ASSOC/W
WITH POTENTIAL STRATUS DEVELOPMENT IN THE 08-14Z TIME FRAME.
MVFR/IFR VISBYS IN FOG WILL ALSO BE POSSIBLE BETWEEN 08-12Z AT THE
FAY/RWI TERMINALS (SIMILAR TO PREVIOUS NIGHTS)...THOUGH THIS WILL
DEPEND ON CLOUD COVER. A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS
IS EXPECTED FRIDAY AFTERNOON AS A LOW-LEVEL TROUGH DEVELOPS IN THE
LEE OF THE APPALACHIANS.
LOOKING AHEAD:
EXPECT AN ABOVE AVERAGE CHANCE FOR SHOWERS AND THUNDERSTORMS
(PRIMARILY AFTERNOON AND EVENING HOURS) SATURDAY THROUGH EARLY TO
MID NEXT WEEK AS A FRONT APPROACHES FROM THE NORTH AND THEN STALLS
OVER THE CAROLINAS/VA IN THE PRESENCE OF CYCLONIC FLOW ALOFT.
MORNING FOG OR STRATUS WILL ALSO BE POSSIBLE EACH DAY... PRIMARILY
IN THE 08-14Z TIME FRAME. -VINCENT
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM..SMITH
LONG TERM...MLM/BAS
AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
457 PM CDT THU AUG 8 2013
.UPDATE...
ISSUED AT 457 PM CDT THU AUG 8 2013
LATEST WATER VAPOR IMAGERY SHOWS NORTHWEST FLOW CONTINUING WITH AN
UPSTREAM MID LEVEL SHORTWAVE LOCATED IN SOUTH CENTRAL SASKATCHEWAN.
REGIONAL RADAR SHOWS ISOLATED RAIN SHOWERS JUST NORTH OF THE MONTANA
BORDER MOVING SOUTHEAST WITH TIME. LIGHT RAIN AT SWIFT CURRENT PER
LATEST SURFACE OBSERVATIONS AND THE GFS HAS THE BEST HANDLE ON THE
PRECIPITATION AREA...WITH THE RAP NOT FAR BEHIND. THE GFS HOLDS A
THIN AREA OF LIGHT SHOWERS TOGETHER AS THEY MOVE INTO NORTHWESTERN
NORTH DAKOTA THIS EVENING AND WILL FOLLOW. THE RAP SHOWS A WEAKENING
OF THE SHOWERS AND KEEPS IT DRY. BASED ON THE LATEST RADAR AND
SURFACE OBSERVATIONS...THINK ENOUGH EVIDENCE UPSTREAM AND IN THE
GFS SOLUTION TO SOLIDIFY A MENTION OF ISOLATED SHOWERS NORTHWEST
INTO PORTIONS OF NORTH CENTRAL TONIGHT. THE GFS H7-H5 RELATIVE
HUMIDITY FIELD ALSO MATCHES THE VISIBLE SATELLITE IMAGERY WELL WHEN
OVERLAID AND THUS WILL INCREASE SKY GRIDS A BIT TO CAPTURE THIS.
ALSO AS MENTIONED FROM THE PREVIOUS DISCUSSION BELOW THE OTHER INTEREST
OVERNIGHT COULD BE OUR FAR SOUTHWEST ZONES...WHERE CONVECTION OVER
NORTHERN WYOMING THIS AFTERNOON IS FORECAST TO BUILD FURTHER NORTH
AND POSSIBLY SEEP INTO THE SOUTHWEST BY AROUND 04Z FRIDAY...PER
RAP MODEL. THE HRRR MODEL HAS CHANGED ITS COURSE BY KEEPING THE
REFLECTIVITY`S SOUTH WHEREAS EARLIER IT ALSO MAKE A TRACK INTO
SOUTHWEST NORTH DAKOTA. WILL CONTINUE TO MONITOR...OTHERWISE
MOSTLY CLEAR TO PARTLY CLOUDY SKIES CAN BE ANTICIPATED FOR THE
REST OF WESTERN AND CENTRAL NORTH DAKOTA THIS EVENING INTO TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
CURRENTLY...HIGH PRESSURE CONTINUES TO BUILD ACROSS WESTERN AND
CENTRAL NORTH DAKOTA. THE COOL HIGH PRESSURE SUPPRESS AND
THUNDERSTORM ACTIVITY LAT THIS AFTERNOON AND TONIGHT. BUT A FEW
SPRINKLES OR AN ISOLATED SHOWER CANNOT BE RULED OUT LATE THIS
AFTERNOON.
TONIGHT...THE SURFACE HIGH PRESSURE RIDGE REMAINS SITUATED
NORTHWEST TO SOUTHEAST ACROSS THE CWA...WHILE SHORTWAVE ENERGY
APPROACHES EASTERN NORTH DAKOTA AND ALSO SOUTHWEST NORTH DAKOTA.
THIS WILL LIKELY RESULT IN LITTLE MORE THAN INCREASING CLOUDS OVER
THE SOUTHWEST AND SOUTH CENTRAL LATE TONIGHT. SOME OF THE MODELS
ARE INDICATING VERY LIGHT QPF IN THE SOUTHWEST BETWEEN 06-12Z
FRIDAY. BUT FOR NOW KEPT WITH THE CURRENT DRY FORECAST. EXPECT A
COOL NIGHT WITH HIGHS RANGING FROM THE MID 40S FAR NORTH TO THE
LOW TO MID 50S FAR SOUTH.
SHORTWAVE ENERGY WORKING THROUGH A NORTHERN ROCKIES UPPER RIDGE
WILL SUPPORT SHOWERS AND THUNDERSTORMS ACROSS SOUTHEAST
MONTANA...NORTHERN WYOMING AND WESTERN SOUTH DAKOTA FRIDAY
AFTERNOON. IT IS POSSIBLE THAT A FEW OF THESE SHOWERS OR
THUNDERSTORMS COULD MOVE INTO THE SOUTHWEST FRIDAY AFTERNOON.
HOWEVER...GUIDANCE CONTINUES TO TREND FARTHER SOUTH SO WILL
CONTINUE WITH PERSISTENCE AND KEEP THINGS DRY ON FRIDAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 317 PM CDT THU AUG 8 2013
A SLOW WARMING TREND POTENTIALLY BACK TO NEAR NORMAL TEMPERATURES
NEXT WEEK WILL HIGHLIGHT THE EXTENDED FORECAST.
THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON NORTHWEST FLOW
ALOFT CONTINUING THROUGH MONDAY...BEFORE A POTENTIAL SHIFT OF THE
UPPER LEVEL RIDGE AXIS ACROSS THE NORTHERN PLAINS TUESDAY ONWARD.
THIS WOULD SUPPORT A SLOW WARMING TREND FROM THE RECENT BELOW NORMAL
TEMPERATURES TO WIDESPREAD HIGHS IN THE 80S BY MID TO LATE NEXT
WEEK. IN REGARDS TO PRECIPITATION CHANCES...THERE IS CHANCE OF
THUNDERSTORMS SATURDAY AND SATURDAY NIGHT AS THE LAST OF THE
SIGNIFICANT WAVES EMBEDDED IN NORTHWEST FLOW PROPAGATES ACROSS THE
NORTHERN PLAINS. THEREAFTER...THUNDERSTORM CHANCES HOLD OFF UNTIL
MID TO LATE NEXT WEEK WITH INCREASING MOISTURE TRANSPORT UNDER THE
RIDGE AHEAD OF LEE SURFACE LOW PRESSURE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 457 PM CDT THU AUG 8 2013
VFR CIGS/VSBYS EXPECTED NEXT 24HR. A WEAK DISTURBANCE IN SOUTH
CENTRAL SASKATCHEWAN WILL GRAZE KISN WITH A VCSH THROUGH 06Z
TONIGHT AND A VCSH INTO KMOT BETWEEN 06Z-12Z FRIDAY. OTHERWISE SCT
TO BKN MID LEVEL CLOUDS WILL MOVE INTO WESTERN AND CENTRAL NORTH
DAKOTA TONIGHT WITH DRY WEATHER ANTICIPATED OVER KDIK/KBIS/KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...TWH
LONG TERM...AYD
AVIATION...KS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
423 PM EDT THU AUG 8 2013
.SYNOPSIS...
A SLOW MOVING FRONTAL SYSTEM WILL PUSH SOUTHEAST TOWARD THE OHIO
RIVER TONIGHT AND FRIDAY. THE FRONT WILL CONTINUE TO PUSH FARTHER
SOUTH FRIDAY NIGHT INTO SATURDAY AS HIGH PRESSURE AND DRIER AIR
BEGIN TO BUILD INTO THE GREAT LAKES. IN THE MEANTIME...A MOIST
AIRMASS WILL ACCOMPANY THE FRONT WITH THE THREAT OF SHOWERS AND
THUNDERSTORMS...AND LOCALLY HEAVY RAINFALL...EXPECTED THROUGH
FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
WILL RELY ON THE RAP AND HRRR MODELS FOR THE NEAR TERM. AS
HELPFUL AS THE MODELS HAVE BEEN IN THE IMMEDIATE NEAR TERM...THE
EVOLUTION OF CONVECTION OVERNIGHT INTO FRIDAY MORNING CONTINUES TO
OSCILLATE WITH EACH SUCCESSIVE RUN...SO WILL DISCUSS THE UNCERTAINTIES
IN THE FORECAST.
A FRONTAL BOUNDARY WAS NEARLY STATIONARY ACRS THE FORECAST AREA
THIS AFTERNOON. SYNOPTIC AND MESOSCALE ANALYSIS SHOWS THAT A WEAK
WAVE OF LOW PRESSURE WAS LOCATED BETWEEN DAYTON AND COLUMBUS. THIS
WAVE ALONG WITH WEAK FRONTAL CONVERGENCE...HAVE LED TO NUMEROUS
SHOWERS AND EMBEDDED THUNDERSTORMS IN THIS REGION WITH SCATTERED
CONVECTION TO THE SOUTH DUE TO THE DAYTIME HEATING AND A MOIST
AIRMASS. THIS WAVE IS EXPECTED TO RIPPLE TO THE NE THIS EVENING...ONLY
TO BE REPLACED BY ANOTHER WAVE OF LOW PRESSURE OVERNIGHT. THE
FOCUS FOR TONIGHT HAS BEEN PLACED ON AN APPARENT MCV CURRENTLY
OVER SRN ILLINOIS PER VISIBLE SATELLITE IMAGERY. THIS MCV IS
FORECAST TO DRIFT ENE THROUGH THE OHIO VALLEY OVERNIGHT. AS IT
DOES...IT SHOULD BE ACCOMPANIED BY A WEAK WAVE OF LOW PRESSURE AT
THE SFC. THE AIRMASS CONTINUES TO SUFFICIENTLY DESTABILIZE AHEAD OF
THIS FEATURE...AND PER MODELS...SHOULD RESULT IN AN UPTICK OF
CONVECTION TO OUR WEST LATE THIS AFTERNOON AND EARLY EVENING AS
THE MCV INTERACTS WITH THIS AIRMASS. THE QUESTION REMAINS HOW AND
WHERE WILL THE BEST FORCING OCCUR AS THE MCV TRAVERSES THE AREA
FROM WEST TO EAST OVERNIGHT. MODELS SUGGEST THAT A SUBTLE LOW
LEVEL JET AND THUS AN INCREASE IN 850 MB MOISTURE TRANSPORT SHOULD
OCCUR AS CONVECTION TRANSITIONS FROM SURFACE BASED TO ELEVATED
BASED. MODELS CONTINUE TO SHOW THAT PWATS WILL BE IN EXCESS OF 2
INCHES WITH THIS FEATURE...ALONG WITH WARM CLOUD DEPTHS IN EXCESS
OF 4 KMS...WHICH FAVORS A COLLISION/COALESCENCE PROCESS. AS A
RESULT...THE THREAT IS THERE FOR VERY HEAVY RAINFALL TO
OCCUR...ESPECIALLY WITH THE MORE INTENSE THUNDERSTORMS. IN
ADDITION...CONVECTION WILL BE SLOW MOVING AND COULD TRAIN OVER THE
SAME AREAS. ALL THESE INGREDIENTS POINT TO AN ENHANCED FLASH FLOOD
THREAT. DURING THE AFTN FORECAST PROCESS...THE RAP AND HRRR
INDICATED THAT THE MCV AND LOW LEVEL JET WOULD INTERACT WITH THE
FRONTAL BOUNDARY TO PRODUCE LIKELY POPS ACRS MUCH OF THE REGION
OVERNIGHT. AS SUCH...FELT AT THE TIME THAT A FFA WAS NEED FOR MOST
OF THE AREA EXCEPT THE FAR NORTHWEST COUNTIES. LATER HRRR AND RAP
RUNS HAVE NOW BEEN SUGGESTING THAT THE MAIN FOCUS MAIN BE MORE ALONG
AND SOUTH OF THE OHIO RIVER. WILL CONTINUE TO MONITOR THIS TO SEE
IF THIS CONTINUES TO TREND THIS WAY. OTHERWISE...WILL STICK TO
THE ORIGINAL THINKING. CONVECTION IS EXPECTED TO WANE TOWARD
MORNING FROM WEST TO EAST AS THE MCV AND SFC WAVE RIPPLE AND THE
FRONTAL BOUNDARY SLOWLY SETTLES TOWARD THE OHIO RIVER. IT MUST BE
POINTED OUT THAT ANOTHER MCV IS UPSTREAM OF THE CURRENT MCV AND IT
IS UNCERTAIN HOW THIS WILL INTERACT WITH THE REGION TOWARD MORNING.
ATTM...HAVE ISSUED A 2 SEGMENTED FFA WITH THE NW 1/2 DROPPING OFF BY
12Z FRIDAY AS CONVECTION SHOULD BECOME MORE FOCUSED TOWARD THE
OHIO RIVER VALLEY. THE SECOND SEGMENT WILL GO UNTIL 00Z SATURDAY.
LOWS TONIGHT WILL RANGE FROM THE MID 60S FAR NW TO THE LOWER 70S
ALONG AND SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRONTAL BOUNDARY WILL SLOWLY DROP SOUTHEAST TOWARD THE OHIO RIVER ON
FRIDAY...THEN SOUTH OF THE OHIO RIVER BY SATURDAY MORNING. HAVE
CONTINUED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS...WITH LIKELY
POPS GIVEN TO LOCATIONS ALONG AND SOUTHEAST OF THE FRONT FRIDAY
AFTERNOON DUE TO DIURNAL HEATING AND ANY POSSIBLE DISTURBANCES
ALOFT PASSING BY. AGAIN...THE THREAT OF HEAVY RAIN WILL CONTINUE
AND THIS IS WHY THE 2 SEGMENT FFA WILL CONTINUE UNTIL 00Z
SATURDAY. INTENSITY AND COVERAGE OF PCPN SHOULD WANE FRIDAY NIGHT
AS THE ATMOSPHERE STABILIZES...AND FRONTAL CONVERGENCE SHIFTS
FARTHER SOUTH. DRIER AIR WILL BEGIN TO BUILD INTO THE NRN ZONES
FRIDAY NIGHT AS HIGH PRESSURE MOVES INTO THE GREAT LAKES REGION.
HIGHS ON FRIDAY WILL BE CLOUD AND PCPN DEPENDENT BUT SHOULD RANGE
FROM THE LOWER TO MID 80S. LOWS FRIDAY NIGHT WILL RANGE FROM THE
LOWER 60S NW TO THE UPPER 60S ALONG AND SOUTH OF THE OHIO RIVER.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
COLD FRONT MAY STILL BE LINGERING IN THE FAR SOUTHERN PART OF THE
FORECAST AREA AT THE BEGINNING OF THE PERIOD BEFORE FINALLY PUSHING
OFF TO THE SOUTH. SO KEPT CHANCE POPS INTO SATURDAY NEAR THIS
BOUNDARY. WENT SLIGHTLY BELOW MOS FOR HIGHS AND THEN LEANED TOWARDS
COOLER NAM GUIDANCE FOR SATURDAY NIGHT LOWS.
HIGH PRESSURE WILL BUILD IN SUNDAY AND MOVE OFF TO THE EAST ON
MONDAY. TEMPERATURES WILL BE NEAR NORMAL DURING THIS TIME FRAME. A
DEVELOPING UPPER TROUGH WILL PUSH A COLD FRONT INTO THE REGION
MONDAY NIGHT INTO TUESDAY. THIS WILL RESULT IN THE NEXT CHANCE OF
SHOWERS AND THUNDERSTORMS. RIDGING WILL RETURN WEDNESDAY AND
THURSDAY AS HIGH PRESSURE SETTLES OVER THE GREAT LAKES BRINGING
ANOTHER COOL AND DRY AIR MASS.
&&
.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
MODERATELY UNSTABLE ATMOSPHERE HAS ACTIVATED AHEAD OF THE CDFNT
WORKING INTO THE REGION. EXPECT CONVECTION TO CONTINUE INTO THE
EVENING WITH THE WEAK FRONTAL CONVERGENCE AND BOUNDARIES ACTING AS
FORCING.
LOOKING TOWARDS OVERNIGHT HOURS...AFT 02Z..,GETTING A WHOLE BUNCH
OF DIFFERENT ANSWERS FROM THE MODELS. SYSTEM OUT OVER MO ATTM
HEADS EAST. MODELS ARE SHOWING DIFFERENT TIMING AND TRACK OF THE
SYSTEM HAS IT APPROACHES THE AREA. THE NAM WEAKENS AND SHUNTS THE
SYSTEM S OF THE TAFS...KEEPING THINGS PRETTY DRY ON FRIDAY. THE 2
CMC MODELS ALONG WITH THE ECMWF BRING IT IN TOWARDS 12Z AND GIVE THE
SRN TAFS THE BEST CHC OF PCPN. THE GFS MEANWHILE LIFTS SI UP RIGHT
ACROSS THE FA ON FRIDAY. LEANED TOWARDS THE MAJORITY FORECAST AND
BROUGHT VCTS/VCSH INTO THE KCVG/KLUK AROUND 09Z. ALSO ABOUT THIS
TIME REDEVELOPED THE FOG AND STRATUS AGAIN. THIS FAR OUT DID NOT
HAVE THE CONFIDENCE TO GO IFR...ESPECIALLY IF WE GET A LOT OF
MIXING FROM PCPN.
THREW A VCSH AT KDAY AND KILN AFT 15Z AS HEATING OF THE ATMOSPHERE
MAY ALLOW CONVECTION TO INITIATE AGAIN AFTER ST BEGINS TO LIFT.
OUTLOOK...THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES
THROUGH FRIDAY....THEN AGAIN MONDAY NIGHT INTO TUESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR OHZ042>046-
051>056-060>065-070>072.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR OHZ073-074-
077>082-088.
KY...FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR KYZ089>100.
IN...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ050-058-059-
066-073-074.
FLASH FLOOD WATCH THROUGH FRIDAY EVENING FOR INZ075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...
AVIATION...SITES
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
618 PM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE REGION THROUGH SATURDAY
KEEPING CHANCES FOR SHOWERS AND THUNDERSTORMS ENHANCED. A COLD
FRONT WILL MOVE INTO THE AREA FROM THE NORTH LATE ON SATURDAY INTO
SUNDAY MORNING KEEPING RAIN CHANCES ELEVATED THROUGH TUESDAY AS IT
SLOWLY MIGRATES SOUTHWARD. SOUTHERLY FLOW WILL RETURN BY WEDNESDAY
ALLOWING FOR A GRADUAL WARMING TREND AND INCREASING MOISTURE.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF LATE AFTERNOON...COVERAGE OF SHOWER ACTIVITY OVER THE WESTERN
CAROLINAS CONTINUES TO DECREASE...SO THE PRECIP CHANCES WERE WOUND
DOWN ACROSS MOST OF THE AREA. HOWEVER...AREA RADARS SHOW EXTENSIVE
THUNDERSTORM ACTIVITY IN SOUTHEASTERN TN...SO EXPECT SOME RESURGENCE
TO COVERAGE AT LEAST OVER THE SW AND SRN MOUNTAINS. NOT SURE IF THIS
WILL MAKE IT OVER OR AROUND THE MTNS...SO ANOTHER UPDATE MIGHT BE
REQUIRED TO BRING THE PRECIP CHANCE BACK UP OVER PARTS OF NE GEORGIA
AND THE UPSTATE THIS EVENING.
PREVIOUS DISCUSSION...
AS OF 235 PM EDT...THE FORECAST AREA WILL REMAIN IN MOSTLY ZONAL
FLOW BETWEEN SHALLOW HIGH PRESSURE ACROSS THE DEEP SOUTH AND A
BETTER BELT OF WESTERLIES FROM THE OH VALLEY NORTHWARD THROUGH THE
NEAR TERM. WEAK MID AND UPPER VORTICITY LOBES WILL CROSS THE AREA
THROUGH THE PERIOD...WITH SLIGHTLY BETTER FORCING AFFECTING THE NRN
TIER. AT LOWER LEVELS...S TO SW FLOW IN THE BOUNDARY LAYER WILL
CONTINUE TO TRIGGER SHOWERS AND TSTMS IN A MOSTLY DIURNAL PATTERN IN
THE MOST SOUTHERLY UPSLOPE FLOW PRONE LOCATIONS. INSTABILITY HAS
STAYED SOMEWHAT LIMITED DUE TO THE CLOUD COVER AND MOIST PROFILES
TODAY...SO ANY SEVERE TSTM THREAT WILL BE QUITE MARGINAL.
HOWEVER...HIGH PRECIPITABLE WATER VALUES AROUND 2 INCHES IN MORNING
RAOBS AND MODEL SOUNDINGS...WARM CLOUD LAYERS OF GENERALLY 12 TO 13
KFT...AND MBE VECTORS LESS THAN 10 KT WILL KEEP THE ISOLATED FLASH
FLOOD THREAT FAIRLY HIGH WITH ANY TRAINING CELLS. WE PLAN ON NO
CURRENT CHANGES TO THE FLASH FLOOD WATCH SINCE THE CURRENT WATCH
AREA APPEARS TO STILL HAVE THE BEST OVERLAP OF FOCUSED...TRAINING
POTENTIAL ALONG WITH SATURATED ANTECEDENT CONDITIONS.
DESPITE THE ABUNDANT...LINGERING MOISTURE AND WEAK...SPORADIC UPPER
WAVE ENERGY OVERNIGHT PRECIP COVERAGE SHOULD GRADUALLY TREND DOWN
OVERNIGHT AS THE MODEL PROFILES QUICKLY DEVELOP A LARGE NEGATIVE
BOUYANCY AREA FROM MID EVENING ONWARD. ANTICIPATE LOW CLOUDS AND FOG
DEVELOPING TOWARD DAYBREAK...BUT THE FOG SHOULD NOT BE PARTICULARLY
DENSE OUTSIDE OF ANY MOUNTAIN RIVER VALLEYS. EXPECT MIN TEMPS ABOVE
GUIDANCE GIVEN THE CLOUD COVER AND RECENT PERFORMANCE.
PROFILES REMAIN MOIST FRI WITH MODEL PWAT VALUES AROUND 2 INCHES
ALONG WITH FAIRLY WEAK STEERING FLOW. IT IS POSSIBLE THAT 850 MB
FLOW MAY BECOME A BIT MORE WESTERLY...AND THIS SLIGHT VEERING COULD
RELIEVE SOME OF THE SRLY UPSLOPE AREAS OF THE BEST CONVECTIVE PRECIP
FOCUS. HOWEVER...BL WINDS MAY CONTINUE MORE SW THROUGH FRI AFTN.
ONCE AGAIN...AN ISOLATED FLASH FLOOD THREAT WILL CONTINUE. WILL
FEATURE MAX TEMPS BELOW GUIDANCE GIVEN THE CLOUD COVER AND RECENT
VERIFICATION.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 200 PM EDT...CHANCES FOR SHOWERS AND THUNDERSTORMS WILL TAPER
OFF SLIGHTLY DURING THE OVERNIGHT HOURS FRIDAY EVENING AS DAYTIME
HEATING FADES. THUS...LOWERED POPS TO CHANCE LEVELS ACROSS THE AREA
WITH THE HIGHEST SOLID CHANCE POPS BEING ALONG THE HIGH TERRAIN
WHERE UPSLOPE FLOW WILL PROLONG THE ACTIVITY. FOR SATURDAY...WEAK
COLD FRONT ASSOCIATED WITH UPPER LOW LOCATED OVER EASTERN CANADA
WILL BE ORIENTED FROM WEST TO EAST AND MOVING SLOWLY OUT OF THE OHIO
VALLEY AND INTO THE TENNESSEE VALLEY REGION. MEANWHILE...DEEP
MOISTURE FETCH WILL REMAIN IN PLACE ACROSS THE SOUTHEASTERN UNITED
STATES AS BERMUDA HIGH DOMINATE THE FLOW. MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT WITH REGARDS TO A DIURNAL TYPE TREND TO THE
CONVECTION ON SATURDAY. THERE WILL BE ENHANCEMENTS OVER THE HIGH
TERRAIN AS LOW LEVEL FLOW CONTINUES TO PROMOTE UPSLOPE COMPONENTS.
THEREFORE...HIGHLIGHTED SOLID CHANCE POPS ACROSS THE UPSTATE AND
NORTHEAST GA REGIONS WITH LIKELY POPS PREVAILING ACROSS MUCH OF
WESTERN NC. AS THE ABOVE MENTIONED SURFACE FRONT MOVES CLOSER TO
THE REGION...WOULD NOT BE SURPRISED TO SEE SOME ADDITIONAL
ENHANCEMENT ALONG THE BOUNDARY ACROSS NORTHWEST NC. DUE TO THE
AMOUNT OF ABUNDANT MOISTURE IN THE PROFILE YIELDING ABOVE CLIMO
PRECIPITABLE WATERS...THINK THE MAIN THREAT SATURDAY WILL BE
LOCALIZED HEAVY RAINFALL AS STEERING FLOW REMAINS WEAK.
MUCH OF THE SAME FOR SUNDAY AS QUASI STATIONARY SURFACE BOUNDARY
REMAINS DRAPED ACROSS THE SOUTHERN APPALACHIANS. MOISTURE CONTENT
THROUGH THE PROFILE WILL REMAIN HIGH...YET SLIGHTLY LESS THAN
PREVIOUS DAYS AS LOW LEVEL FLOW SHIFTS MORE WESTERLY. WITH THAT
BEING SAID...KEPT NEARLY THE SAME POP FORECAST AS SATURDAY WITH
LIKELY POPS RESIDING ACROSS MUCH OF WESTERN NC AND CHANCE POPS
ELSEWHERE. DUE TO SLIGHTLY LESS SKY COVER ACROSS THE REGION ON
SUNDAY...WOULD NOT BE SURPRISED TO SEE GREATER INSTABILITY AS MORE
SUNSHINE ALLOWS FOR ADDITIONAL HEATING. THUS...SOME SCATTERED
AFTERNOON THUNDERSTORMS ARE POSSIBLE. TEMPERATURES THROUGH THE
SHORT TERM PERIOD WILL REMAIN AT OR SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM EDT...SURFACE FRONTAL BOUNDARY WILL MOVE SOUTHWARD INTO
THE LOW COUNTRY AND DRAPE WESTWARD ACROSS THE MID GULF COAST
STATES ON MONDAY. MEANWHILE...SLIGHTLY DRIER AIR WILL WORK ITS WAY
IN ACROSS THE REGION FOR THE START OF THE WORK WEEK.
HOWEVER...WESTERLY LOW LEVEL FLOW WILL ALLOW FOR ENHANCED UPSLOPE
CONVECTION ACROSS THE HIGH TERRAIN ON MONDAY WHERE LIKELY POPS WILL
PREVAIL. THE ABOVE MENTIONED BOUNDARY WILL PROVIDE A FOCUS FOR
THUNDERSTORM ACTIVITY ACROSS THE MIDLANDS AND PERHAPS INTO THE
UPSTATE OF SC THROUGH MIDWEEK. KEPT ABOVE CLIMO POPS IN THE
FORECAST THROUGH THE REMAINDER OF THE PERIOD AS SOUTHERLY FLOW
GRADUALLY RETURNS ALLOWING FOR INCREASING MOISTURE ACROSS THE AREA.
TEMPERATURES THROUGH THE EXTENDED PERIOD WILL REMAIN A FEW DEGREES
BELOW NORMAL.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
AT KCLT...THE LATEST HRRR MODEL RUN HAS CAPTURED THE LINE OF WEAK
CONVECTION W OF THE AIRFIELD THIS AFTN. STILL NOT SEEING ANY
LIGHTNING WITH THIS...BUT TEMPO TSRA WAS MOVED UP TO 19Z TO ACCOUNT
FOR EARLIER TRIGGERING AS THIS ACTIVITY MOVES E. GIVEN THE LOW
LCL/CCL...CIGS WILL LIKELY REMAIN LOWER VFR AND QUICKLY TOGGLE OVER
INTO MVFR WITH ANY SHOWERS AT THE AIRFIELD. CANNOT RULE OUT SOME
BRIEF IFR VSBY WITH ANY HEAVIER DOWNPOURS BUT CONFIDENCE IS TOO LOW
TO FORECAST THAT. ANTICIPATE COVERAGE TO DWINDLE GRADUALLY LATE THIS
EVENING THROUGH THE OVERNIGHT...WITH RESONABLE CHANCES OF AT LEAST
MVFR RESTRICTIONS EARLY FRI GIVEN THE LOW LEVEL MOISTURE. WILL
REINTRODUCE VCSH ALONG WITH GRADUAL IMPROVEMENT INTO VFR LATE FRI
MORNING AND WILL HOLD OFF ON ANY FRI THUNDER POTENTIAL UNTIL AFTER
18Z. WINDS SHOULD REMAIN SW AT LESS THAN 10 KT THROUGH THE
PERIOD...ASIDE FROM ANY TSTMS.
ELSEWHERE...COVERAGE OF WEAK CONVECTION IS GRADUALLY FILLING IN
ACROSS THE REGION THIS AFTN. HAVE STARTED TEMPO TSRA EARLIEST AT
KAVL...BUT WILL NEED SOME MENTION BY ABOUT 19Z AT THE FOOTHILL TAF
SITES AS WELL. EXPECT CIGS TO ALTERNATE BETWEEN MVFR AND VFR THROUGH
LATE DAY...WITH BRIEF IFR CONDITIONS POSSIBLE WITH ANY HEAVY
DOWNPOURS. COVERAGE WILL GRADUALLY DIMINISH TONIGHT...WITH A RETURN
OF MVFR CIGS LIKELY BY DAYBREAK AT THE UPSTATE TAFS...IFR AT KAVL BY
09Z...AND TEMPO IFR AT KHKY AT TIMES. EXPECT SLOW IMPROVEMENT
THROUGH LATE MORNING WITH VCSH RETURNING TO THE FORECAST. WILL ONLY
MENTION PROB30 FOR TSRA AT KAVL PRIOR TO 18Z GIVEN THE EARLIEST MTN
ONSET WITH TERRAIN UPSLOPE. EXPECT MAINLY LIGHT SW WINDS THROUGH THE
PERIOD...EXCEPT VRB NEAR TSTMS.
OUTLOOK...DEEP MOISTURE AND DAILY SHOWER/TSTM TRIGGERING WILL
CONTINUE THROUGH THE WEEKEND. IFR TO MVFR RESTRICTIONS LOOK LIKELY
LATE EACH NIGHT/EARLY EACH MORNING...WITH ADDITIONAL RESTRICTIONS
UNDER ANY CONVECTION. CONDITIONS MAY STAY UNSETTLED THROUGH EARLY
NEXT WEEK DEPENDING ON THE SWD PROGRESS OF A WEAK FRONT THROUGH THE
AREA.
CONFIDENCE TABLE...
22-04Z 04-10Z 10-16Z 16-22Z
KCLT HIGH 100% HIGH 91% HIGH 88% HIGH 100%
KGSP HIGH 93% MED 61% HIGH 81% HIGH 100%
KAVL MED 76% MED 66% MED 70% HIGH 89%
KHKY HIGH 81% MED 76% MED 75% HIGH 100%
KGMU HIGH 86% MED 63% HIGH 81% HIGH 94%
KAND HIGH 100% HIGH 95% HIGH 90% HIGH 83%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH UNTIL 6 AM EDT FRIDAY FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...CDG
NEAR TERM...HG/PM
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
241 PM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW WILL REMAIN ACROSS THE REGION THROUGH SATURDAY
KEEPING CHANCES FOR SHOWERS AND THUNDERSTORMS ENHANCED. A COLD
FRONT WILL MOVE INTO THE AREA FROM THE NORTH LATE ON SATURDAY INTO
SUNDAY MORNING KEEPING RAIN CHANCES ELEVATED THROUGH TUESDAY AS IT
SLOWLY MIGRATES SOUTHWARD. SOUTHERLY FLOW WILL RETURN BY WEDNESDAY
ALLOWING FOR A GRADUAL WARMING TREND AND INCREASING MOISTURE.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 235 PM EDT...THE FORECAST AREA WILL REMAIN IN MOSTLY ZONAL
FLOW BETWEEN SHALLOW HIGH PRESSURE ACROSS THE DEEP SOUTH AND A
BETTER BELT OF WESTERLIES FROM THE OH VALLEY NORTHWARD THROUGH THE
NEAR TERM. WEAK MID AND UPPER VORTICITY LOBES WILL CROSS THE AREA
THROUGH THE PERIOD...WITH SLIGHTLY BETTER FORCING AFFECTING THE NRN
TIER. AT LOWER LEVELS...S TO SW FLOW IN THE BOUNDARY LAYER WILL
CONTINUE TO TRIGGER SHOWERS AND TSTMS IN A MOSTLY DIURNAL PATTERN IN
THE MOST SOUTHERLY UPSLOPE FLOW PRONE LOCATIONS. INSTABILITY HAS
STAYED SOMEWHAT LIMITED DUE TO THE CLOUD COVER AND MOIST PROFILES
TODAY...SO ANY SEVERE TSTM THREAT WILL BE QUITE MARGINAL.
HOWEVER...HIGH PRECIPITABLE WATER VALUES AROUND 2 INCHES IN MORNING
RAOBS AND MODEL SOUNDINGS...WARM CLOUD LAYERS OF GENERALLY 12 TO 13
KFT...AND MBE VECTORS LESS THAN 10 KT WILL KEEP THE ISOLATED FLASH
FLOOD THREAT FAIRLY HIGH WITH ANY TRAINING CELLS. WE PLAN ON NO
CURRENT CHANGES TO THE FLASH FLOOD WATCH SINCE THE CURRENT WATCH
AREA APPEARS TO STILL HAVE THE BEST OVERLAP OF FOCUSED...TRAINING
POTENTIAL ALONG WITH SATURATED ANTECEDENT CONDITIONS.
DESPITE THE ABUNDANT...LINGERING MOISTURE AND WEAK...SPORADIC UPPER
WAVE ENERGY OVERNIGHT PRECIP COVERAGE SHOULD GRADUALLY TREND DOWN
OVERNIGHT AS THE MODEL PROFILES QUICKLY DEVELOP A LARGE NEGATIVE
BOUYANCY AREA FROM MID EVENING ONWARD. ANTICIPATE LOW CLOUDS AND FOG
DEVELOPING TOWARD DAYBREAK...BUT THE FOG SHOULD NOT BE PARTICULARLY
DENSE OUTSIDE OF ANY MOUNTAIN RIVER VALLEYS. EXPECT MIN TEMPS ABOVE
GUIDANCE GIVEN THE CLOUD COVER AND RECENT PERFORMANCE.
PROFILES REMAIN MOIST FRI WITH MODEL PWAT VALUES AROUND 2 INCHES
ALONG WITH FAIRLY WEAK STEERING FLOW. IT IS POSSIBLE THAT 850 MB
FLOW MAY BECOME A BIT MORE WESTERLY...AND THIS SLIGHT VEERING COULD
RELIEVE SOME OF THE SRLY UPSLOPE AREAS OF THE BEST CONVECTIVE PRECIP
FOCUS. HOWEVER...BL WINDS MAY CONTINUE MORE SW THROUGH FRI AFTN.
ONCE AGAIN...AN ISOLATED FLASH FLOOD THREAT WILL CONTINUE. WILL
FEATURE MAX TEMPS BELOW GUIDANCE GIVEN THE CLOUD COVER AND RECENT
VERIFICATION.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 200 PM EDT...CHANCES FOR SHOWERS AND THUNDERSTORMS WILL TAPER
OFF SLIGHTLY DURING THE OVERNIGHT HOURS FRIDAY EVENING AS DAYTIME
HEATING FADES. THUS...LOWERED POPS TO CHANCE LEVELS ACROSS THE AREA
WITH THE HIGHEST SOLID CHANCE POPS BEING ALONG THE HIGH TERRAIN
WHERE UPSLOPE FLOW WILL PROLONG THE ACTIVITY. FOR SATURDAY...WEAK
COLD FRONT ASSOCIATED WITH UPPER LOW LOCATED OVER EASTERN CANADA
WILL BE ORIENTED FROM WEST TO EAST AND MOVING SLOWLY OUT OF THE OHIO
VALLEY AND INTO THE TENNESSEE VALLEY REGION. MEANWHILE...DEEP
MOISTURE FETCH WILL REMAIN IN PLACE ACROSS THE SOUTHEASTERN UNITED
STATES AS BERMUDA HIGH DOMINATE THE FLOW. MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT WITH REGARDS TO A DIURNAL TYPE TREND TO THE
CONVECTION ON SATURDAY. THERE WILL BE ENHANCEMENTS OVER THE HIGH
TERRAIN AS LOW LEVEL FLOW CONTINUES TO PROMOTE UPSLOPE COMPONENTS.
THEREFORE...HIGHLIGHTED SOLID CHANCE POPS ACROSS THE UPSTATE AND
NORTHEAST GA REGIONS WITH LIKELY POPS PREVAILING ACROSS MUCH OF
WESTERN NC. AS THE ABOVE MENTIONED SURFACE FRONT MOVES CLOSER TO
THE REGION...WOULD NOT BE SURPRISED TO SEE SOME ADDITIONAL
ENHANCEMENT ALONG THE BOUNDARY ACROSS NORTHWEST NC. DUE TO THE
AMOUNT OF ABUNDANT MOISTURE IN THE PROFILE YIELDING ABOVE CLIMO
PRECIPITABLE WATERS...THINK THE MAIN THREAT SATURDAY WILL BE
LOCALIZED HEAVY RAINFALL AS STEERING FLOW REMAINS WEAK.
MUCH OF THE SAME FOR SUNDAY AS QUASI STATIONARY SURFACE BOUNDARY
REMAINS DRAPED ACROSS THE SOUTHERN APPALACHIANS. MOISTURE CONTENT
THROUGH THE PROFILE WILL REMAIN HIGH...YET SLIGHTLY LESS THAN
PREVIOUS DAYS AS LOW LEVEL FLOW SHIFTS MORE WESTERLY. WITH THAT
BEING SAID...KEPT NEARLY THE SAME POP FORECAST AS SATURDAY WITH
LIKELY POPS RESIDING ACROSS MUCH OF WESTERN NC AND CHANCE POPS
ELSEWHERE. DUE TO SLIGHTLY LESS SKY COVER ACROSS THE REGION ON
SUNDAY...WOULD NOT BE SURPRISED TO SEE GREATER INSTABILITY AS MORE
SUNSHINE ALLOWS FOR ADDITIONAL HEATING. THUS...SOME SCATTERED
AFTERNOON THUNDERSTORMS ARE POSSIBLE. TEMPERATURES THROUGH THE
SHORT TERM PERIOD WILL REMAIN AT OR SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM EDT...SURFACE FRONTAL BOUNDARY WILL MOVE SOUTHWARD INTO
THE LOW COUNTRY AND DRAPE WESTWARD ACROSS THE MID GULF COAST
STATES ON MONDAY. MEANWHILE...SLIGHTLY DRIER AIR WILL WORK ITS WAY
IN ACROSS THE REGION FOR THE START OF THE WORK WEEK.
HOWEVER...WESTERLY LOW LEVEL FLOW WILL ALLOW FOR ENHANCED UPSLOPE
CONVECTION ACROSS THE HIGH TERRAIN ON MONDAY WHERE LIKELY POPS WILL
PREVAIL. THE ABOVE MENTIONED BOUNDARY WILL PROVIDE A FOCUS FOR
THUNDERSTORM ACTIVITY ACROSS THE MIDLANDS AND PERHAPS INTO THE
UPSTATE OF SC THROUGH MIDWEEK. KEPT ABOVE CLIMO POPS IN THE
FORECAST THROUGH THE REMAINDER OF THE PERIOD AS SOUTHERLY FLOW
GRADUALLY RETURNS ALLOWING FOR INCREASING MOISTURE ACROSS THE AREA.
TEMPERATURES THROUGH THE EXTENDED PERIOD WILL REMAIN A FEW DEGREES
BELOW NORMAL.
&&
.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
AT KCLT...THE LATEST HRRR MODEL RUN HAS CAPTURED THE LINE OF WEAK
CONVECTION W OF THE AIRFIELD THIS AFTN. STILL NOT SEEING ANY
LIGHTNING WITH THIS...BUT TEMPO TSRA WAS MOVED UP TO 19Z TO ACCOUNT
FOR EARLIER TRIGGERING AS THIS ACTIVITY MOVES E. GIVEN THE LOW
LCL/CCL...CIGS WILL LIKELY REMAIN LOWER VFR AND QUICKLY TOGGLE OVER
INTO MVFR WITH ANY SHOWERS AT THE AIRFIELD. CANNOT RULE OUT SOME
BRIEF IFR VSBY WITH ANY HEAVIER DOWNPOURS BUT CONFIDENCE IS TOO LOW
TO FORECAST THAT. ANTICIPATE COVERAGE TO DWINDLE GRADUALLY LATE THIS
EVENING THROUGH THE OVERNIGHT...WITH RESONABLE CHANCES OF AT LEAST
MVFR RESTRICTIONS EARLY FRI GIVEN THE LOW LEVEL MOISTURE. WILL
REINTRODUCE VCSH ALONG WITH GRADUAL IMPROVEMENT INTO VFR LATE FRI
MORNING AND WILL HOLD OFF ON ANY FRI THUNDER POTENTIAL UNTIL AFTER
18Z. WINDS SHOULD REMAIN SW AT LESS THAN 10 KT THROUGH THE
PERIOD...ASIDE FROM ANY TSTMS.
ELSEWHERE...COVERAGE OF WEAK CONVECTION IS GRADUALLY FILLING IN
ACROSS THE REGION THIS AFTN. HAVE STARTED TEMPO TSRA EARLIEST AT
KAVL...BUT WILL NEED SOME MENTION BY ABOUT 19Z AT THE FOOTHILL TAF
SITES AS WELL. EXPECT CIGS TO ALTERNATE BETWEEN MVFR AND VFR THROUGH
LATE DAY...WITH BRIEF IFR CONDITIONS POSSIBLE WITH ANY HEAVY
DOWNPOURS. COVERAGE WILL GRADUALLY DIMINISH TONIGHT...WITH A RETURN
OF MVFR CIGS LIKELY BY DAYBREAK AT THE UPSTATE TAFS...IFR AT KAVL BY
09Z...AND TEMPO IFR AT KHKY AT TIMES. EXPECT SLOW IMPROVEMENT
THROUGH LATE MORNING WITH VCSH RETURNING TO THE FORECAST. WILL ONLY
MENTION PROB30 FOR TSRA AT KAVL PRIOR TO 18Z GIVEN THE EARLIEST MTN
ONSET WITH TERRAIN UPSLOPE. EXPECT MAINLY LIGHT SW WINDS THROUGH THE
PERIOD...EXCEPT VRB NEAR TSTMS.
OUTLOOK...DEEP MOISTURE AND DAILY SHOWER/TSTM TRIGGERING WILL
CONTINUE THROUGH THE WEEKEND. IFR TO MVFR RESTRICTIONS LOOK LIKELY
LATE EACH NIGHT/EARLY EACH MORNING...WITH ADDITIONAL RESTRICTIONS
UNDER ANY CONVECTION. CONDITIONS MAY STAY UNSETTLED THROUGH EARLY
NEXT WEEK DEPENDING ON THE SWD PROGRESS OF A WEAK FRONT THROUGH THE
AREA.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% MED 76% MED 79%
KGSP HIGH 100% MED 78% LOW 58% MED 75%
KAVL MED 76% MED 62% MED 67% MED 69%
KHKY MED 74% MED 64% MED 68% HIGH 87%
KGMU HIGH 97% MED 71% LOW 58% MED 70%
KAND HIGH 97% HIGH 100% MED 75% MED 65%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...CDG
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...HG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
219 PM EDT THU AUG 8 2013
.SYNOPSIS...
MOIST HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH SATURDAY. A
WEAK COLD FRONT WILL ARRIVE FROM THE NORTH ON SUNDAY. THIS FRONT
WILL SLOWLY CROSS THE AREA THROUGH TUESDAY...BEFORE MOVING SOUTH OF
THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 215 PM EDT...THE FORECAST AREA WILL GENERALLY REMAIN IN ZONAL
FLOW BETWEEN SHALLOW HIGH PRESSURE ACROSS THE DEEP SOUTH AND A
BETTER BELT OF WESTERLIES FROM THE OH VALLEY NORTHWARD THROUGH THE
NEAR TERM. WEAK MID AND UPPER VORTICITY LOBES WILL CROSS THE AREA
THROUGH THE PERIOD...WITH SLIGHTLY BETTER FORCING AFFECTING THE NRN
TIER. AT LOWER LEVELS...S TO SW FLOW IN THE BOUNDARY LAYER WILL
CONTINUE TO TRIGGER SHOWERS AND TSTMS IN A MOSTLY DIURNAL PATTERN IN
THE MOST SOUTHERLY UPSLOPE FLOW PRONE LOCATIONS. INSTABILITY HAS
STAYED SOMEWHAT LIMITED DUE TO THE CLOUD COVER AND MOIST PROFILES
TODAY...SO ANY SEVERE TSTM THREAT WILL BE QUITE MARGINAL.
HOWEVER...HIGH PRECIPITABLE WATER VALUES AROUND 2 INCHES IN MORNING
RAOBS AND MODEL SOUNDINGS...WARM CLOUD LAYERS OF GENERALLY 12 TO 13
KFT...AND MBE VECTORS LESS THAN 10 KT WILL KEEP THE ISOLATED FLASH
FLOOD THREAT FAIRLY HIGH WITH ANY TRAINING CELLS. WE PLAN ON NO
CURRENT CHANGES TO THE FLASH FLOOD WATCH SINCE THE CURRENT WATCH
AREA APPEARS TO STILL HAVE THE BEST OVERLAP OF FOCUSED...TRAINING
POTENTIAL ALONG WITH SATURATED ANTECEDENT CONDITIONS.
DESPITE THE ABUNDANT...LINGERING MOISTURE AND WEAK...SPORADIC UPPER
WAVE ENERGY OVERNIGHT PRECIP COVERAGE SHOULD GRADUALLY TREND DOWN
OVERNIGHT AS THE MODEL PROFILES QUICKLY DEVELOP A LARGE NEGATIVE
BOUYANCY AREA FROM MID EVENING ONWARD. ANTICIPATE LOW CLOUDS AND FOG
DEVELOPING TOWARD DAYBREAK...BUT THE FOG SHOULD NOT BE PARTICULARLY
DENSE OUTSIDE OF ANY MOUNTAIN RIVER VALLEYS. EXPECT MIN TEMPS ABOVE
GUIDANCE GIVEN THE CLOUD COVER AND RECENT PERFORMANCE.
PROFILES REMAIN MOIST FRI WITH MODEL PWAT VALUES AROUND 2 INCHES
ALONG WITH FAIRLY WEAK STEERING FLOW. IT IS POSSIBLE THAT 850 MB
FLOW MAY BECOME A BIT MORE WESTERLY...AND THIS SLIGHT VEERING COULD
RELIEVE SOME OF THE SRLY UPSLOPE AREAS OF THE BEST CONVECTIVE PRECIP
FOCUS. HOWEVER...BL WINDS MAY CONTINUE MORE SW THROUGH FRI AFTN.
ONCE AGAIN...AN ISOLATED FLASH FLOOD THREAT WILL CONTINUE. WILL
FEATURE MAX TEMPS BELOW GUIDANCE GIVEN THE CLOUD COVER AND RECENT
VERIFICATION.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 200 PM EDT...CHANCES FOR SHOWERS AND THUNDERSTORMS WILL TAPER
OFF SLIGHTLY DURING THE OVERNIGHT HOURS FRIDAY EVENING AS DAYTIME
HEATING FADES. THUS...LOWERED POPS TO CHANCE LEVELS ACROSS THE AREA
WITH THE HIGHEST SOLID CHANCE POPS BEING ALONG THE HIGH TERRAIN
WHERE UPSLOPE FLOW WILL PROLONG THE ACTIVITY. FOR SATURDAY...WEAK
COLD FRONT ASSOCIATED WITH UPPER LOW LOCATED OVER EASTERN CANADA
WILL BE ORIENTED FROM WEST TO EAST AND MOVING SLOWLY OUT OF THE OHIO
VALLEY AND INTO THE TENNESSEE VALLEY REGION. MEANWHILE...DEEP
MOISTURE FETCH WILL REMAIN IN PLACE ACROSS THE SOUTHEASTERN UNITED
STATES AS BERMUDA HIGH DOMINATE THE FLOW. MODEL GUIDANCE REMAINS IN
GOOD AGREEMENT WITH REGARDS TO A DIURNAL TYPE TREND TO THE
CONVECTION ON SATURDAY. THERE WILL BE ENHANCEMENTS OVER THE HIGH
TERRAIN AS LOW LEVEL FLOW CONTINUES TO PROMOTE UPSLOPE COMPONENTS.
THEREFORE...HIGHLIGHTED SOLID CHANCE POPS ACROSS THE UPSTATE AND
NORTHEAST GA REGIONS WITH LIKELY POPS PREVAILING ACROSS MUCH OF
WESTERN NC. AS THE ABOVE MENTIONED SURFACE FRONT MOVES CLOSER TO
THE REGION...WOULD NOT BE SURPRISED TO SEE SOME ADDITIONAL
ENHANCEMENT ALONG THE BOUNDARY ACROSS NORTHWEST NC. DUE TO THE
AMOUNT OF ABUNDANT MOISTURE IN THE PROFILE YIELDING ABOVE CLIMO
PRECIPITABLE WATERS...THINK THE MAIN THREAT SATURDAY WILL BE
LOCALIZED HEAVY RAINFALL AS STEERING FLOW REMAINS WEAK.
MUCH OF THE SAME FOR SUNDAY AS QUASI STATIONARY SURFACE BOUNDARY
REMAINS DRAPED ACROSS THE SOUTHERN APPALACHIANS. MOISTURE CONTENT
THROUGH THE PROFILE WILL REMAIN HIGH...YET SLIGHTLY LESS THAN
PREVIOUS DAYS AS LOW LEVEL FLOW SHIFTS MORE WESTERLY. WITH THAT
BEING SAID...KEPT NEARLY THE SAME POP FORECAST AS SATURDAY WITH
LIKELY POPS RESIDING ACROSS MUCH OF WESTERN NC AND CHANCE POPS
ELSEWHERE. DUE TO SLIGHTLY LESS SKY COVER ACROSS THE REGION ON
SUNDAY...WOULD NOT BE SURPRISED TO SEE GREATER INSTABILITY AS MORE
SUNSHINE ALLOWS FOR ADDITIONAL HEATING. THUS...SOME SCATTERED
AFTERNOON THUNDERSTORMS ARE POSSIBLE. TEMPERATURES THROUGH THE
SHORT TERM PERIOD WILL REMAIN AT OR SLIGHTLY BELOW NORMAL.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AT 230 AM EDT THURSDAY...AN UPPER TROUGH WILL AMPLIFY ALONG THE EAST
COAST FROM SUNDAY THROUGH WEDNESDAY. A COLD FRONT WILL DROP VERY
SLOWLY SOUTH INTO THE NORTHERN PORTION OF THE AREA ON SUNDAY...
CROSSING MUCH OF WESTERN NC ON MONDAY...THE INTERSTATE 85 CORRIDOR
TUESDAY...AND FINALLY MOVING SOUTH OF THE AREA ON WEDNESDAY.
ALTHOUGH THIS BOUNDARY WILL SERVE AS A FOCUSING MECHANISM FOR
PRECIPITATION...SOUTHERLY INFLOW AHEAD OF THE FRONT IS EXPECTED TO
DECREASE BASED ON A REORIENTATION OF THE SURFACE RIDGE TO THE SOUTH.
UPSLOPE WILL BE LIMITED TO THE TN BORDER AREA TO BEGIN WITH AS LOW
LEVEL WINDS WILL BE WESTERLY...AND WILL DIMINISH IN THE LEE OF THE
MOUNTAINS AS THE FRONT SETTLES SOUTH AND WINDS VEER MORE TO THE
NORTHWEST. POPS WILL REMAIN ABOVE CLIMATOLOGY...AND WITH SOME
UNCERTAINTY AS TO THE TIMING OF THE FRONT...POPS WILL BE ALLOWED TO
REMAIN INTO WEDNESDAY. TEMPERATURES WILL DECREASE AS HEIGHTS FALL
ALOFT...BUT THE DIURNAL RANGE WILL REMAIN LIMITED DUE TO CLOUDS AND
MOISTURE.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...THE LATEST HRRR MODEL RUN HAS CAPTURED THE LINE OF WEAK
CONVECTION WEST OF THE AIRFIELD EARLY THIS AFTN. STILL NOT SEEING
ANY LIGHTNING WITH THIS...BUT HAVE MOVED THE TEMPO TSRA UP TO 19Z TO
ACCOUNT FOR EARLIER TRIGGERING AS THIS ACTIVITY MOVES EAST. GIVEN
THE LOW LCL/CCL...CIGS WILL LIKELY REMAIN LOWER VFR AND QUICKLY
TOGGLE OVER INTO MVFR WITH ANY SHOWERS AT THE AIRFIELD. CANNOT RULE
OUT SOME BRIEF IFR VSBY WITH ANY HEAVIER DOWNPOURS BUT CONFIDENCE IS
TOO LOW TO FORECAST THAT. ANTICIPATE COVERAGE TO DWINDLE GRADUALLY
LATE THIS EVENING THROUGH THE OVERNIGHT...WITH RESONABLE CHANCES OF
AT LEAST MVFR RESTRICTIONS EARLY FRI GIVEN THE LOW LEVEL MOISTURE.
WILL REINTRODUCE VCSH ALONG WITH GRADUAL IMPROVEMENT INTO VFR LATE
FRI MORNING AND WILL HOLD OFF ON ANY FRI THUNDER POTENTIAL UNTIL
AFTER 18Z. WINDS SHOULD REMAIN SW AT LESS THAN 10 KT THROUGH THE
PERIOD...ASIDE FROM ANY TSTMS.
ELSEWHERE...COVERAGE OF WEAK CONVECTION IS GRADUALLY FILLING IN
ACROSS THE REGION THIS AFTN. HAVE STARTED TEMPO TSRA EARLIEST AT
KAVL...BUT WILL NEED SOME MENTION BY ABOUT 19Z AT THE FOOTHILL TAF
SITES AS WELL. EXPECT CIGS TO ALTERNATE BETWEEN MVFR AND VFR THROUGH
LATE DAY...WITH BRIEF IFR CONDITIONS POSSIBLE WITH ANY HEAVY
DOWNPOURS. COVERAGE WILL GRADUALLY DIMINISH TONIGHT...WITH A RETURN
OF MVFR CIGS LIKELY BY DAYBREAK AT THE UPSTATE TAFS...IFR AT KAVL BY
09Z...AND TEMPO IFR AT KHKY AT TIMES. EXPECT SLOW IMPROVEMENT
THROUGH LATE MORNING WITH VCSH RETURNING TO THE FORECAST. WILL ONLY
MENTION PROB30 FOR TSRA AT KAVL PRIOR TO 18Z GIVEN THE EARLIEST MTN
ONSET WITH TERRAIN UPSLOPE. EXPECT MAINLY LIGHT SW WINDS THROUGH THE
PERIOD...EXCEPT VRB NEAR TSTMS.
OUTLOOK...DEEP MOISTURE AND DAILY SHOWER/TSTM TRIGGERING WILL
CONTINUE THROUGH THE WEEKEND. IFR TO MVFR RESTRICTIONS LOOK LIKELY
LATE EACH NIGHT/EARLY EACH MORNING...WITH ADDITIONAL RESTRICTIONS
UNDER ANY CONVECTION. CONDITIONS MAY STAY UNSETTLED THROUGH EARLY
NEXT WEEK DEPENDING ON THE SWD PROGRESS OF A WEAK FRONT THROUGH THE
AREA.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% MED 76% MED 79%
KGSP HIGH 100% MED 78% LOW 58% MED 75%
KAVL MED 76% MED 62% MED 67% MED 69%
KHKY MED 74% MED 64% MED 68% HIGH 87%
KGMU HIGH 97% MED 71% LOW 58% MED 70%
KAND HIGH 97% HIGH 100% MED 75% MED 65%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR GAZ010-017-018-026-
028-029.
NC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR NCZ062>065-509-510.
SC...FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR SCZ001>007-010>012-
019.
&&
$$
SYNOPSIS...HG/JAT
NEAR TERM...HG
SHORT TERM...CDG
LONG TERM...JAT
AVIATION...HG
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1238 PM CDT THU AUG 8 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
MADE A FEW ADJUSTMENTS TO WX/POPS FOR TODAY...MAINLY JUST SHAVING
OFF THE NORTH END WHERE CONDITIONS LOOK TO BE DRY NORTH OF THE
STALLED FRONTAL BOUNDARY. ANY ADDITIONAL SHOWER AND STORM
DEVELOPMENT THROUGH THE DAY LOOKS TO BE MAINLY NEAR AND SOUTH OF
HWY 212. LATEST HRRR RUN AND LAST NIGHTS 00Z NSSL WRF RUN ALSO
SUGGESTING THIS. CURRENT HIGHS APPEAR ON TRACK AT THIS POINT AND
NO CHANGES THERE. READINGS WILL TOP OUT IN THE 70S FOR MOST
LOCATIONS...STILL BELOW NORMAL FOR THIS TIME OF YEAR.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN AREA OF HIGH PRESSURE MOVING INTO THE REGION FROM THE NORTH
WILL PUSH A WEAK FRONTAL BOUNDARY DRAPED FROM WEST TO EAST ACROSS
CENTRAL SOUTH DAKOTA SOUTHWARD TODAY. MODELS GENERALLY AGREE WITH
PLACEMENT OF THIS FRONTAL BOUNDARY ACROSS SOUTHERN SOUTH DAKOTA
WHERE STORMS HAVE THE BEST POTENTIAL OF DEVELOPING LATER THIS
AFTERNOON. BECAUSE OF THE SOUTHERN PLACEMENT OF THE FRONTAL BOUNDARY
HAVE REMOVED POPS ACROSS THE NORTHERN PORTION OF THE CWA FOR THIS
AFTERNOON.
CANADIAN HIGH PRESSURE BUILDING INTO THE REGION TONIGHT WILL
PRODUCE DRY CONDITIONS THROUGH THE DAY ON FRIDAY. RETURN FLOW WILL
QUICKLY DEVELOP ON THE BACK SIDE OF THE HIGH PRESSURE ON FRIDAY
NIGHT OVER THE WESTERN DAKOTAS. A FAIRLY STRONG SHORT WAVE MOVING
ACROSS THE REGION WILL INTERACT WITH THE INCREASING LLM TO RESULT
IN EARLY MORNING CONVECTION FOR THE WESTERN CWA ON SATURDAY.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
DESPITE ALLBLENDS GENEROUS SMATTERING OF POPS OVER SEVERAL OF THE
EXTENDED FORECAST PERIODS...SATURDAY NIGHT/SUNDAY STILL STANDS THE
BEST CHANCE OF NUMEROUS/WIDESPREAD COVERAGE OF SHOWERS AND
THUNDERSTORMS. INSTABILITY/SHEAR AND FORCING IS ALL THERE IN
SUPPORT OF SOME SORT OF ORGANIZED CONVECTIVE SYSTEM
EVOLVING/MOVING ACROSS THE CWA SATURDAY NIGHT INTO SUNDAY MORNING.
BEYOND THAT...AS WAS PREVIOUSLY MENTIONED...DETAILS GET A LITTLE
BIT FUZZIER AS SOLUTIONS BEGIN TO DIVERGE ON THE HANDLING OF
PLACEMENT/STRENGTH OF THE WESTERN CONUS UPPER LEVEL RIDGE /AND ANY
SHORT-WAVE IMPULSES EMBEDDED WITHIN THE FLOW/ WHICH IS THOUGHT TO
BE SHIFTING A BIT EAST TOWARD THE DAKOTAS BY MID-WEEK.
ALSO STILL LOOKS AS THOUGH TEMPERATURES MAY TRY TO
MODERATE/WARM-UP A BIT TOWARD THE MID TO LATE PART OF THIS COMING
WEEK...AT LEAST...CLOSER TO NORMAL FOR AUGUST.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
OTHER THAN SOME MVFR CIGS LINGERING OVER PARTS OF THE EASTERN CWA
INTO THE EARLY TO MID AFTERNOON HOURS...VFR CONDITIONS WILL
PREVAIL ACROSS THE AREA THROUGH MIDDAY FRIDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...SD
LONG TERM...DORN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1016 AM MDT THU AUG 8 2013
.UPDATE...
ISSUED AT 1015 AM MDT THU AUG 8 2013
SYNOPTIC SITUATION FOR LATER TODAY IS SIMILAR TO THAT OF
WEDNESDAY. PRECIPITATABLE WATER VALUES ARE SLIGHTLY HIGHER AND
STILL CONSIDERABLE MID AND UPPER LEVEL MOISTURE REMAINS OVER
MUCH OF THE CWA. LOW CLOUDS HAVE BEEN SLOWLY ERODING OVER THE
AREA THROUGH MID MORNING WITH ONLY THE AREAS BETWEEN K82V AND
KSNY AND KSNY AND KAIA STILL REPORTING LOW CLOUDS. THAT TREND
SHOULD CONTINUE SLOWLY THROUGH THE REST OF THE DAY. THE
TEMPERATURES WILL BE SIMILAR TODAY AND BELOW NORMAL IN MANY
AREAS. THOSE COOL TEMPERATURES AND THE EXISTING CLOUD COVER
WILL AGAIN ACT TO HINDER STORM ACTIVITY LATER TODAY. HOWEVER...
MAY BE MORE BREAKS IN THOSE CLOUDS TODAY AND ALREADY SHOWERS
ARE DEVELOPING OVER CARBON COUNTY. AT THIS TIME...BELIEVE THE
ACTIVITY WILL BE MORE A BIT WIDESPREAD THAN THAT OF WEDNESDAY
AS A WEAK MID LEVEL CIRCULATION WILL MOVE NEAR THE SOUTH PART
OF THE CWA AND SURFACE FORCING WILL PERSIST. STRONGER STORMS MAY
BE MORE POSSIBLE IN THE NORTH PART OF THE CWA WHERE TEMPERATURES
WILL BE WARMER. IN GENERAL...THE STRONGER STORMS WILL PRODUCE
HEAVY RAIN...BRIEF WIND GUSTS TO 45 MPH AND SMALL HAIL AND WILL
BE SLOWL MOVING. PREVIOUS FORECAST IS IN GOOD SHAPE AND IN A
RECENT UPDATE TOOK OUT THE EARLY MORNING FOG AND ADDED HEAVY
RAIN AND SMALL HAIL MENTION TO THE STORMS LATER TODAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 312 AM MDT THU AUG 8 2013
AREAS OF FOG HAVE DEVELOPED ACROSS FAR SOUTHEAST WY THIS MORNING IN
RESPONSE TO MOIST SOUTH-TO-SOUTHEAST LLVL FLOW ALONG AND EAST OF THE
LARAMIE RANGE. VSBYS AT KCYS HAVE BEEN REDUCED TO ONE QUARTER OF A
MILE AT TIMES OVER THE PAST FEW HOURS...AND AREA WEBCAMS SHOW DENSE
FOG TO BE FAIRLY WIDESPREAD ACROSS CENTRAL AND EASTERN PORTIONS OF
LARAMIE COUNTY. MAIN QUESTION IS HOW LONG THIS FOG WILL LAST AS
WINDS MAY DEVELOP A SLIGHT SOUTHWEST COMPONENT EARLY THIS AM...WHICH
WOULD TEND TO SCOUR OUR EXISTING LLVL MOISTURE. ASSOCIATED -DZ COULD
ALSO LIMIT DENSE FOG POTENTIAL. LATEST HRRR RUNS STILL SHOW VERY LOW
VSBYS THROUGH ABOUT 15Z THOUGH...SO HAVE ISSUED A DENSE FOG ADVISORY
FOR THE I80 CORRIDOR BETWEEN THE SUMMIT AND NEBRASKA STATE LINE
THROUGH MID AM TO COVER AT LEAST THE NEAR TERM THREAT FOR HAZARDOUS
TRAVEL.
EVEN IF FOG DOES NOT PERSIST...LOW STRATUS SHOULD CREATES A FORECAST
HEADACHE FOR THU AFTN AND EVE. 11-3.9 MICROMETER IR CHANNEL SUGGESTS
LLVL CLOUDS ARE BECOMING RATHER WIDESPREAD FROM THE LARAMIE RANGE
EWD INTO THE WESTERN NE PANHANDLE. MIGHT BE TOUGH TO BURN OFF CLOUD
COVER TODAY AS EASTERLY UPSLOPE FLOW BECOMES ESTABLISHED OVER THE
HIGH PLAINS. GIVEN THIS AND 700 MILLIBAR TEMPS TO BE PROGGED ABOUT
1-2 DEG COOLER THAN WED...HAVE TRENDED A FEW DEGREES BELOW MOS GUID
FOR FCST HIGHS WHERE CLOUDS SHOULD BE THICKEST. NATURALLY THIS ALSO
LEADS TO QUESTIONS WITH INSTABILITY AND POSSIBLE CONVECTION LATER
IN THE DAY ON TOP OF AN ALREADY COMPLICATED SYNOPTIC SETUP.
A DIRTY UPPER-LEVEL RIDGE WILL BUILD INTO SOUTH CENTRAL WY THIS AFTN
WITH NUMEROUS MIDLVL DISTURBANCES LIKELY INTERACTING WITH MONSOONAL
MOISTURE IN THE 700-300 MILLIBAR LAYER. THIS...ALONG WITH UPPER-LEVEL
DIVERGENCE IN THE RIGHT REAR QUADRANT OF A MIDWEST US JET STREAK AND
UPSLOPING LLVL FLOW SHOULD CONTRIBUTE TO SUFFICIENT LIFT FOR SHOWER
AND TSTM DEVELOPMENT LATER TODAY. THE BEST DYNAMICS APPEAR TO DROP
TO THE SOUTH WITH A STRONGER WAVE EVIDENT ON WATER VAPOR SATELLITE
OVER EASTERN UT AND WESTERN CO...WHICH COULD LIMIT OVERALL COVERAGE
OF PCPN IN OUR CWA. ESSENTIALLY BETWEEN SYSTEMS...FLOW ALOFT SHOULD
BE WEAK WITH ONLY AROUND 10-15 KTS OF 700-500 MILLIBAR FLOW. LESS
THAN 30 KTS OF EFFECTIVE SHEAR SHOULD KEEP SEVERE STORMS AT BAY...
EVEN IF THE MUCH MORE UNSTABLE NAM WOULD VERIFY WITH SURFACE CAPES
IN EXCESS OF 1500 J/KG. THINKING INSTABILITY WILL BE MODEST AT BEST
THOUGH WITH LIMITED DAYTIME HEATING...BUT MIDLVL COOLING WILL YIELD
SUFFICIENT ELEVATED INSTABILITY FOR TSTM DEVELOPMENT. OVERALL THREAT
FROM CONVECTION WILL BE HEAVY RAIN FROM SLOW MOVING STORMS...THOUGH
PWATS ARE NOT PARTICULARLY HIGH WITH SOME MOISTURE BEING ROBBED BY
THE SYSTEM TO THE SOUTH.
TRYING NOT TO SOUND LIKE A BROKEN RECORD...PERSISTENCE IS THE NAME
OF THE GAME AS WE HEAD INTO FRIDAY. SEVERAL WEAK DISTURBANCES ARE
LIKELY TO TRAVERSE THE FLOW ALONG THE EDGE OF THE CENTRAL ROCKIES
RIDGE...MOST OF WHICH ARE TOO WEAK TO ACCURATELY PREDICT WITH ANY
REASONABLE DEGREE OF ACCURACY. WITH ABUNDANT SUBTROPICAL MOISTURE
REMAINING IN PLACE OVER THE AREA...OVERALL PATTERN FAVORS ANOTHER
COOL DAY WITH SCATTERED SHOWERS AND STORMS WITH CONTINUED UPSLOPE
FLOW IN THE LLVLS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 342 AM MDT THU AUG 8 2013
ACTIVE WEATHER PATTERN TO REMAIN IN PLACE THROUGH THE EXTENDED
FORECAST PERIOD. THE ONLY POTENTIAL CHANGE IS FOR THE UPPER LEVEL
RIDGE CURRENTLY OVER THE ROCKIES TO EXPAND NORTHWARD. BOUTS OF
MONSOON MOISTURE SHOULD CONTINUE TO SNEAK UNDER THE RIDGE AND
INFLUENCE THE FORECAST AREA WITH CHANCES FOR AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS...WHILE TEMPERATURES SHOULD BE NEAR TO
SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD. WITH THE RIDGE IN PLACE
UPPER LEVEL WINDS WILL BE ON THE LIGHT SIDE WHICH SHOULD SERVE TO
MINIMIZE SEVERE WEATHER CHANCES. HIGH TEMPERATURES WILL MAINLY BE
IN THE 80S WITH LOWS IN THE 50S FOR AREAS OUTSIDE OF THE
MOUNTAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1015 AM MDT THU AUG 8 2013
VISIBILITIES HAVE IMPROVED OVER THE SOUTH PART OF THE CWA AND
AS OF 15Z WERE VFR. STILL AREAS OF LOW CLOUDS BETWEEN K82V
AND KSNY AND KSNY AND KAIA. THE LOW CLOUDS SHOULD CONTINUE TO
SLOWLY ERODE AND CEILINGS LIFT WITH VFR CEILINGS BY THE MID TO
LATE AFTERNOON OVER THOSE AREAS.
A SCATTERED COVERAGE OF AFTERNOON AND EVENING SHOWERS WILL
AFFECT THE CWA AND WILL PRODUCE BRIEF MVFR CEILINGS AND
VISIBILITIES IN RAIN ALONG WITH GUSTY WINDS. THE MOUNTAINS MAY
BE OBSCURED AT TIMES.
AREAS OF LOW CLOUDS AND FOG WILL REDEVELOP OVER MAINLY THE
SOUTHERN PANHANDLE AFTER 08Z AND PERSIST THROUGH 15Z FRIDAY.
THEN ANOTHER ROUND OF SCATTERED SHOWERS AND STORMS WILL AFFECT
MUCH OF THE CWA FRIDAY AFTERNOON AND EVENING.
&&
.FIRE WEATHER...
ISSUED AT 312 AM MDT THU AUG 8 2013
FIRE WEATHER CONCERNS WILL BE MINIMAL OVER THE NEXT FEW DAYS AS
MONSOON MOISTURE REMAINS IN PLACE OVER THE REGION. TEMPERATURES
WILL BE NORMAL OR SLIGHTLY BELOW WITH AT LEAST SCATTERED SHOWERS
AND STORMS EACH AFTERNOON AND EVENING THROUGH FRIDAY. DRYING IS
EXPECTED ACROSS WESTERN CARBON AND CONVERSE COUNTIES DURING THE
WEEKEND WITH AFTERNOON RELATIVE HUMIDITY VALUES FALLING BELOW 15
PERCENT. HOWEVER WINDS ARE EXPECTED TO REMAIN BELOW THE CRITICAL
THRESHOLDS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...WEILAND
SHORT TERM...HAMMER
LONG TERM...LIEBL
AVIATION...WEILAND
FIRE WEATHER...HAMMER