Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/18/14
AREA FORECAST DISCUSSION
NWS PUEBLO CO
255 PM MDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 236 PM MDT SAT AUG 16 2014
AN UPR RIDGE WL REMAIN CENTERED OVR NORTHERN AZ TONIGHT AND
SUNDAY. THIS AFTERNOON...WV SATELLITE IMAGERY SHOWING DRIER AIR
PUSHING EASTWARD ACRS THE STATE. HOWEVER THERE IS STILL ENOUGH
MSTR OUT THERE...THAT WITH THE AFTERNOON INSTABILITY...ISOLATED
SHOWERS/TSTMS HAVE DEVELOPED OVR THE SERN PLAINS WHERE THE MSTR IS
A LITTLE BETTER...AND ISOLATED TO SCATTERED CONVECTION HAS
DEVELOPED OVR THE MTNS. WILL KEEP ISOLD TO SCT SHOWERS/TSTMS IN
THE FORECAST ACRS THE AREA THRU THE EVENING HOURS...THEN SHOULD
SEE DECREASING PCPN CHANCES AFTER SUNSET. THE RAP AND HRRR SHOW
ALL PCPN ENDING BY MIDNIGHT. THE NAM KEEPS SOME PCPN GOING ACRS
MAINLY THE SEN PLAINS INTO THE LATE NIGHT. FOR NOW HAVE DECIDED TO
GO WITH RAP AND HRRR AND END ALL PCPN BY MIDNIGHT IN THE FORECAST.
THE NAM SHOWS SLIGHTLY LOWER PRECIPITABLE WATER VALUES ACRS THE
FORECAST AREA ON SUN...BUT THERE WL STILL BE ENOUGH MSTR AND
INSTABILITY FOR SHOWERS AND TSTMS TO DEVELOP. IT SHOULD START OVR
THE MTNS IN THE LATE MORNING/EARLY AFTERNOON HOURS WITH ISOLD TO SCT
COVERAGE IN THE AFTERNOON AND EVENING HOURS. SOME ISOLATED
SHOWERS/STORMS SHOULD DEVELOP OVR THE SERN PLAINS IN THE AFTERNOON
AS WELL. HIGH TEMPS ON SUN WL AGAIN BE A LITTLE ABOVE AVERAGE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 236 PM MDT SAT AUG 16 2014
...MONSOON CONTINUES THROUGH NEXT WEEK...
THE TYPICAL SUMMER MONSOON WE HAVE BEEN DEALING WITH LOOKS
TO CONTINUE THROUGH NEXT WEEK. THE UPPER HIGH TO OUR SW WILL
SHIFT INTO ERN OK/TX AS A TROUGH OVER THE PACNW ADVANCES
EWD...AND THIS WILL KEEP A STEADY STREAM OF SUBTROPICAL
MOISTURE OVER OUR AREA.
SUN NIGHT...MODELS HAVE BEEN VERY CONSISTENT IN DEVELOPING
A LINE/CLUSTER OF STORMS OVER E-CENTRAL CO BY EARLY EVENING
IN A WEAK BAROCLINIC ZONE. THIS MCS WILL SHIFT SLOWLY SWD
DURING THE EVENING. EXPECT THE HEAVIEST QPF TO BE OVER ERN
AL PASO AND KIOWA COUNTIES. SHOULD CLEAR OUT AFTER MIDNIGHT.
MONDAY...WEAK UPSLOPE WILL PROVIDE AN EXTRA TRIGGER FOR MORE
PM STORMS...PROBABLY A BIT MORE COVERAGE OVER THE PLAINS THAN ON
PRECEDING DAYS. IT WILL BE ANOTHER VERY WARM DAY WITH SOME
MID 90S OVER THE HOT SPOTS ON THE PLAINS.
BY TUESDAY...WILL START TO SEE INCREASING MOISTURE MOVE NWD OVER
WRN CO AS A CUTTOFF DROPS ACROSS THE SRN CA COAST AND THE PACNW
TROUGH BEGINS MOVING INLAND. STILL SOME UNCERTAINTY ON HOW WELL
THE CUTOFF WILL PHASE WITH THE NRN JET BRANCH...AND THIS WILL
AFFECT HOW MUCH RAIN TO EXPECT OVER OUR AREA NEXT WEEK INTO NEXT
WEEKEND. HOWEVER...IT APPEARS LIKELY THAT THERE WILL BE
INCREASING SRLY FLOW AHEAD OF THE PACNW TROUGH...WHICH WILL LEAD
TO INCREASING HEAVY RAIN CONCERNS FOR THE CENTRAL MTS/CONTDVD TUE-
WED...AND THEN THE ERN RANGES AND POSSIBLY PLAINS BY LATE IN THE
WEEK. IF THE CUTOFF GETS PICKED UP SOONER BY THE ADVANCING
TROUGH...WE COULD SEE ENHANCED PRECIP OVER OUR WHOLE CWA. THE
LATEST 12Z ECMWF IS MUCH MORE AGGRESSIVE WITH PHASING THE LOW AND
PACNW TROUGH...AND WOULD BRING SIGNIFICANT PRECIP TO OUR AREA FOR
THE LATTER PART OF THE WEEK. FOR NOW...WILL STAY THE COURSE WITH
CONSERVATIVE LOW POPS FOR THE PLAINS AND TYPICAL SCT/CHANCE POPS
FOR THE MTS. WILL HAVE TO SEE HOW THINGS GO OVER THE NEXT COUPLE
OF DAYS...BUT IT BEARS WATCHING FOR THE POTENTIAL OF MORE
FLOODING...PARTICULARLY FOR THE MTS. ROSE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 236 PM MDT SAT AUG 16 2014
VFR CONDITIONS ARE EXPECTED AT KCOS...KPUB AND KALS TONIGHT THROUGH
SUNDAY AFTERNOON. IT IS POSSIBLE THAT TSTMS COULD MOVE INTO THE
VCNTY OF THE TERMINAL SITES THIS EVENING...AND AGAIN BY MID TO LATE
AFTERNOON ON SUNDAY.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...ROSE
AVIATION...28
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1120 AM MDT SAT AUG 16 2014
.UPDATE...
ISSUED AT 1108 AM MDT SAT AUG 16 2014
FIRST STORMS OF THE DAY FIRING ALONG THE ABAJO MOUNTAINS IN
SOUTHEAST UTAH AND ACROSS THE SOUTHERN EXTENT OF THE UNCOMPAHGRE
PLATEAU NEAR DALLAS DIVIDE. THIS ACTIVITY IS EXPECTED TO CONTINUE
THROUGH THIS AFTERNOON AND INTO THE EARLY EVENING HOURS. NO
SIGNIFICANT WAVES AND SHEAR PROFILES REMAIN WEAK...SO STORMS
EXPECTED TO BE SHORT-LIVED AND CONFINED TO THE HIGHER TERRAIN.
EXCEPTION WILL BE ACROSS THE SOUTHERN VALLEYS SOUTH OF THE SAN
JUANS WITH LATEST HRRR RUN SUGGESTIONS A FEW STRONGER STORMS
DRIFTING SOUTH OFF THE SAN JUANS BETWEEN 2 AND 5 PM THIS
AFTERNOON. THIS MAY IMPACT THE DURANGO AND PAGOSA SPRINGS AREAS
WITH GUSTY WINDS...SMALL HAIL AND BRIEF HEAVY RAIN.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 340 AM MDT SAT AUG 16 2014
WATER VAPOR SHOWS DRIER AIR ALOFT ADVECTING ACROSS UTAH AND WRN
COLORADO...BUT ALSO EVIDENT IS AN EMBEDDED DISTURBANCE THAT
MANAGED TO KEEP PERSISTENT NOCTURNAL THUNDERSTORMS IN THE
VICINITY OF KCNY...ARCHES NP...AND MOAB FOR A FEW HOURS. HIGH
PRESSURE OVER UTAH AND WRN COLORADO AND ITS DRIER AIR MASS WILL
BE THE DOMINANT FEATURE TODAY. HOWEVER LOWER LEVEL MOISTURE
(SURFACE DEW POINTS REMAIN AROUND 50F) AND STEEP AFTERNOON LAPSE
RATES WILL TRIGGER SOME AFTERNOON CONVECTION. THE AIR MASS IS
DRIER TODAY AS PRECIPITABLE WATER VALUES HAVE DROPPED TO THREE
QUARTERS OF AN INCH (PER KGJT SOUNDING). AREAL COVERAGE OF STORMS
WILL BE LESS NUMEROUS THAN FRIDAY AFTERNOON. NO DISTURBANCE IS
EVIDENT IN THE MODEL DATA...SO STRONG SURFACE HEATING WILL BE THE
PRIMARY TRIGGER MECHANISM.
A DISTURBANCE PASSES THROUGH THE CANADIAN ROCKIES TONIGHT
FLATTENING THE RIDGE. A VERY WEAK ASSOCIATED WAVE PASSES ALONG THE
CO-WY BORDER...BUT MOISTURE LOOKS VERY LIMITED. SO NOCTURNAL
STORMS ARE NOT EXPECTED.
SUNDAY...PRECIPITABLE WATER VALUES ARE AROUND 0.6 INCH WHICH IS
LOW FOR MID AUGUST. ISOLATED AFTERNOON STORMS ARE POSSIBLE OVER
ALL MOUNTAINS WITH LITTLE RAINFALL CHANCE IN THE VALLEYS. STORM
MOTION WILL BE TO THE EAST AT AROUND 15 KTS. AFTERNOON
TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 340 AM MDT SAT AUG 16 2014
LITTLE CHANGE IS EXPECTED SUNDAY NIGHT THROUGH MONDAY. THE BROAD
RIDGE IS CENTERED NEAR THE FOUR CORNERS WITH ONLY MARGINAL
RESIDUAL MOISTURE AVAILABLE FOR LATE-DAY STORMS. A TROUGH IS
DEVELOPING ALONG THE WEST COAST. MOISTURE BEGINS TO SURGE INTO SE
UTAH AS EARLY AS MONDAY AFTERNOON OR EVENING. THERE IS STILL SOME
UNCERTAINTY ON THE TIMING AND DEPTH OF THIS MOISTURE SURGE. BUT
THE GFS AND SREF PRODUCE PRECIPITABLE WATER VALUES OVER AN INCH IN
SE UTAH TOWARDS TUESDAY MORNING. HAVE ADDED ISOLATED LATE NIGHT
THUNDERSTORMS SPREADING NORTHWARD ALONG THE UT-CO STATELINE.
INCREASING CONFIDENCE THAT THE MONSOONAL MOISTURE TAP DEEPENS BY
TUESDAY AND WILL LAST INTO NEXT FRIDAY. THE GFS REMAINS THE MOST
AGGRESSIVE MODEL WITH A SIGNIFICANT LONG WAVE TROUGH ALONG THE
WEST COAST THAT STRENGTHENS THE SOUTHERLY COMPONENT. WITH
TIME...ENERGY EMBEDDED IN THE WESTERLIES ABSORBS THE CLOSED LOW
WITH SHORT WAVE ENERGY MOVING ACROSS THE GREAT BASIN TOWARD THE
CENTRAL ROCKIES. THE ECMWF MODEL SHOWS THE MID LEVEL CLOSED LOW
CIRCULATION ALONG THE CENTRAL CALIFORNIA COAST...ALLOWING FOR A
MONSOONAL MOISTURE INTO UTAH AND COLORADO. BUT THE ECMWF ALLOWS
THE CLOSED LOW TO RETROGRADE WESTWARD. SOME UNCERTAINTY ON HOW
THIS EVOLVES NEXT WEEK AND THIS WILL DICTATE THE STRENGTH OF THIS
MONSOONAL SURGE AND AREAL COVERAGE OF THUNDERSTORMS AND NOCTURNAL
STORM ACTIVITY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1108 AM MDT SAT AUG 16 2014
ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS THE HIGHER TERRAIN
THROUGH 03Z THIS EVENING. A FEW STORMS WILL DRIFT SOUTH OFF THE
SAN JUAN MOUNTAINS...POSSIBLY IMPACTING KDRO AND KPSO. GUSTY WINDS
TO 45 MPH...SMALL HAIL AND BRIEF HEAVY RAINFALL WILL BE POSSIBLE
WITH ANY STORMS. KTEX...KDRO AND KPSO WILL SEE A 30 PERCENT CHANCE
OF THUNDERSTORMS THROUGH 03Z THIS EVENING...OTHERWISE...VFR
CONDITIONS CONTINUE.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...PF/JOE
LONG TERM...JOE/PF
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1120 PM MDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 244 PM MDT FRI AUG 15 2014
CONVECTION THIS AFTERNOON HAS BEEN MORE SPARSE TODAY VS
YESTERDAY...AT LEAST AS OF 20Z. HOWEVER...THE MTNS HAVE HAD MORE
SUN TODAY...AND THUNDERSTORMS ARE FIRING OVER THE MOUNTAINS ALONG
THE LEADING EDGE OF A WEAK SHORTWAVE MOVING INTO WESTERN CO.
VARIOUS HIGH RES MODELS INCREASE THUNDERSTORM COVERAGE ACROSS THE
MOUNTAINS...THEN SPREAD THEM EASTWARD INTO THE ADJACENT PLAINS
DURING THE AFTERNOON AND EVENING HOURS. SFC DEW POINTS HAVE BEEN
LOWER TODAY...DROPPING OFF INTO THE LOWER 40S AND EVEN SOME UPPER
30S ACROSS THE MOUNTAINS...WITH UPPER 40S TO MID 50S ACROSS THE
PLAINS...AND THIS HAS LIMITED CAPE TO AROUND 500 J/KG ACCORDING TO
SPC MESO ANALYSIS. PRECIP WATERS ARE RUNNING LOWER AS
WELL...AROUND 80% OF NORMAL IN THE NORTH TO 130% OF NORMAL IN THE
SOUTH BASED ON THE BLENDED TPW SATELLITE PRODUCT.
THUS...THUNDERSTORMS SHOULD NOT BE AS EFFICIENT HEAVY RAINFALL
PRODUCERS AS THEY WERE YESTERDAY. THAT SAID...THERE IS STILL
SUFFICIENT MOISTURE FOR LOCALLY HEAVY RAIN WITH THE STRONGER
STORMS. IF ONE OF THESE HITS BURN SCARS OR AREAS OF STEEP
TERRAIN...THEN LOCALIZED FLASH FLOODING WILL STILL BE A CONCERN.
FORTUNATELY...STORMS APPEAR TO BE MOVING PRETTY GOOD (SOUTHEAST AT
15 MPH)...WHICH MAY LIMIT THREAT SOME. HRRR SUGGESTS GREATEST
THREAT WINDOW FOR THE WALD0 WILL BE FROM 21Z-00Z. THE PAPOOSE AND
WEST FORK BURN SCARS AS WELL AS THE CONTINENTAL DIVIDE WILL SEE
THE GREATEST THREAT BETWEEN 20Z AND 00Z. THUNDERSTORMS MAY MOVE
OFF INTO THE ADJACENT PLAINS THROUGH THE LATE AFTERNOON AND
EVENING...BUT THEY DON`T LOOK TOO ORGANIZED AND THERE ISN`T MUCH
OF A LOW LEVEL JET TO HELP SUSTAIN CONVECTION AFTER DARK...SO WILL
END MOST POPS BY MIDNIGHT.
SATURDAY LOOKS EVEN DRIER THAN TODAY AS PRECIPITABLE WATERS FALL OFF
TO LESS THAN AN .75 INCHES ALONG/WEST OF I-25. STILL ENOUGH
MOISTURE FOR ISOLATED DIURNAL THUNDERSTORMS...BUT COVERAGE SHOULD BE
EVEN LOWER. STILL ENOUGH MOISTURE FOR LOCALLY HEAVY RAIN WITH THE
STRONGER CELLS...BUT THREAT SHOULD BE LOWER DUE TO THE LIMITED
COVERAGE. TEMPERATURES TOMORROW SHOULD BE A FEW DEGREES WARMER THAN
TODAY. -KT
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 244 PM MDT FRI AUG 15 2014
EXTENDED FORECAST FOR SE CO LOOKS PRETTY TYPICAL FOR THE MIDDLE
OF AUGUST. DAILY STORM CHANCES AND TEMPS AROUND 90 DEGREES FOR THE
PLAINS. MAIN QUESTION WILL BE THE PROGRESSION OF A W COAST CUTOFF
LOW AND PACNW TROUGH...ESPECIALLY LATE IN THE PERIOD.
SAT NIGHT...CONVECTION SHOULD BE WRAPPING UP PRETTY EARLY AFTER
SUNSET. WILL LEAVE HIGHEST POPS SAT EVE OVER THE RATON MESA AND
FAR SERN PLAINS...WHERE THE MODELS ARE FOCUSING THE HEAVIEST QPF.
SUNDAY...A SHORT WAVE DISTURBANCE WILL PUSH THROUGH IN THE NW FLOW
LATE IN THE DAY. LOOKS LIKE THE MAIN IMPACT FROM THIS DISTURBANCE
WILL COME AFTER 00Z...AND BE FOCUSED ON THE PIKES PEAK REGION AND
PALMER DVD. EXPECT STORMS TO DEVELOP OVER THE MTS SOMEWHAT LATER
THAN USUAL...MOSTLY AFTER 20Z...AND IT WILL BE ISOLD-SCT IN COVERAGE.
THE SHORTWAVE SHOULD RESULT IN MORE WIDESPREAD COVERAGE OF STORMS
BUT THERE IS STILL SOME UNCERTAINTY ON HOW FAR WEST THE BULK OF THE
DEVELOPING CLUSTER OF STORMS WILL BE. HAVE THE HIGHEST POPS FROM THE
PIKES PEAK AREA SEW TO KLAA...FROM 00-03Z. SUNDAY SHOULD BE THE
WARMEST DAY OF THE PERIOD AS H7 TEMPS CLIMB TO NR 17 DEG C IN THE
AFTERNOON. COULD SEE A FEW SPOTS CLIMB INTO THE UPPER 90S OVER THE
LOWER ARKANSAS VALLEY.
MONDAY...THE MAIN FOCUS FOR ANY CONVECTION WILL BE OVER THE ERN
MTS AS LIGHT UPSLOPE FLOW PERSISTS ON THE BACKSIDE OF THE TROUGH
MOVING THROUGH THE UPPER MISS VALLEY. WILL KEEP ISOLD-SCT POPS THERE
WITH MORE ISOLD ACTIVITY POSSIBLE OVER THE BALANCE OF THE ERN PLAINS
AND SAN LUIS VALLEY. IF TRENDS CONTINUE...MAY BE ABLE TO DROP
MENTIONABLE POPS FROM ALL BUT THE MTS ON MONDAY.
TUESDAY...WILL SEE THE START OF A SWITCH BACK TO INCREASING MONSOONAL
MOISTURE. THE CUTOFF OFF THE CA COAST MAY BEGIN TO RETROGRADE DURING
THIS PERIOD...WHILE A TROUGH IN THE PACNW BEGINS MOVING INTO ID AND
MT. THE ECMWF CONTINUES OT BE A LITTLE MORE AGGRESSIVE IN BRINGING A
RETURN OF MONSOONAL MOISTURE TO THE AREA...WHILE THE GFS HOLDS BACK
A BIT. LOW POPS LOOK APPROPRIATE FOR THE REGION...ISOLD FOR THE
LOWER ELEVS AND SCT IN THE MTS.
BY WED-FRI...THE PACNW TROUGH SHOULD START TO ADVANCE INTO THE NRN
ROCKIES...AS THE UPPER HIGH TO OUR SW SHIFTS INTO ERN TX. THIS SHOULD
BRING A RETURN TO A STRONGER MONSOONAL PATTERN...WITH MORE MOISTURE
BEING DRAWN NWD FROM THE SUBTROPICS INTO WRN CO. WILL LEAVE LOW
ENSEMBLE POPS INTACT FOR NOW...BUT IF TRENDS CONTINUE MAY HAVE TO
SLOWLY RAMP UP POPS FOR THE END OF THE WEEK. ROSE
&&
.AVIATION...ISSUED AT 1120 PM MDT FRI AUG 15 2014
VFR CONDITIONS ARE EXPECTED OVER THE KALS...KCOS AND KPUB TAF
SITES FROM TONIGHT INTO SATURDAY.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
136 PM EDT SAT AUG 16 2014
.SYNOPSIS...
WEAK HIGH PRESSURE WILL INFLUENCE THE MID ATLANTIC TODAY. A COLD
FRONT WILL APPROACH FROM THE GREAT LAKES TONIGHT BEFORE MOVING
THROUGH THE AREA SUNDAY. THE FRONT WILL STALL TO THE SOUTH OF THE
AREA MONDAY. A WAVE OF LOW PRESSURE WILL TRACK ALONG THE FRONTAL
BOUNDARY AND ACROSS THE MID-ATLANTIC REGION MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY. HIGH PRESSURE WILL BECOME
ESTABLISHED ACROSS THE SOUTHERN AND CENTRAL UNITED STATES LATE IN
THE WEEK WHILE A SERIES OF DISTURBANCES TRACK AROUND THE NORTHERN
PERIPHERY OF THE HIGH AND THROUGH OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH THE 12:30 AM UPDATE MAXIMUM TEMPERATURES WERE LOWERED
SLIGHTLY AS SOME HIGH CLOUDS HAS PREVENTED MAXIMUM HEATING TODAY.
DEWPOINTS HAVE ALSO BEEN LOWERED SOME ACROSS THE 1-95 CORRIDOR IN
LINE WITH THE RECENT METAR OBS. THINK THE RAP IS OVERDONE WITH
SHOWERS DOWN SOUTH FOR THIS AFTERNOON AND HAVE REMOVED THIS
PRECIPITATION CHANCE FROM THE FORECAST.
THE MAJORITY OF THE REGION WILL STAY RAIN FREE TODAY WITH THE
ONLY EXCEPTION BEING EXTREME SOUTHERN DELMARVA. A WEAK MID- LEVEL
IMPULSE MOVING THROUGH OUR SOUTH, ALONG AN OLD FRONTAL BOUNDARY,
TOUCHED OFF A FEW SHOWERS IN SOUTHERN MARYLAND THAT WILL DRIFT
OVER EXTREME SOUTHERN DELMARVA THIS MORNING. ACROSS MOST OF THE
REGION SOUTHWEST WINDS WILL ALLOW FOR BETTER THERMAL ADVECTION
UNDER MOSTLY SUNNY SKIES AS THERE IS PLENTY OF DRY ALOFT TO MIX
DOWN.
TEMPERATURES WERE A BLEND OF THE MET/MAV GUIDANCE WITH A HEAVIER
WEIGHING TOWARDS THE COOLER MET TODAY. THE NAM INITIALIZED BETTER AT
850 AND 925MB COMPARED TO THE MAV, HENCE THE SLIGHT EDGE TOWARDS THE
MET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
A SLOW MOVING COLD FRONT APPROACHES FROM THE NORTHWEST LATE TONIGHT
INTO SUNDAY. CONTINUED AIRMASS MODIFICATION TONIGHT, WITH DEWPOINTS
RISING TOWARDS 60F, COULD PROVIDE ENOUGH MOISTURE FOR THE
APPROACHING FRONT TO TAP INTO. THE BETTER FORCING LOOKS TO REMAIN
OUR NORTHWEST ZONES LATE TONIGHT BUT A FEW STRAY SHOWERS COULD DRIFT
ACROSS OUR NORTHERN ZONES BY TOMORROW MORNING...WE KEEP THE CHANCE
POPS GOING. OVERNIGHT LOWS WILL BE A FEW DEGREES WARMER THAN THIS
MORNING WITH THE WARMER STARTING POINT AND INCREASING CLOUD COVER
EXPECTED.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
ON SUNDAY, THE MID-ATLANTIC REGION WILL BE POSITIONED TOWARD THE
BASE OF AN UPPER TROUGH THAT IS ASSOCIATED WITH A CLOSED LOW OVER
EASTERN CANADA. 00Z MODEL GUIDANCE IN REASONABLY GOOD AGREEMENT WITH
THE SFC COLD FRONT MOVING THRU THE ERN PA/NJ SUNDAY MORNING. MAY SEE
A LINGERING SHOWER IN THE PA MTS TO START THE DAY. FARTHER EAST,
REMOVED MENTION OF SHOWERS WITH THE BEST UPPER FORCING FROM THE
TROUGH MOVING AWAY FROM THE AREA AND LLVL DOWNSLOPING/WLY FLOW
HELPING TO SCOUR OUT MOISTURE. HOWEVER, SRN PORTION OF THE FRONT IS
FORECAST TO GET HUNG UP OVER NERN MD INTO THE DELMARVA UNDER WEAKER
STEERING FLOW ALOFT. MODELS GENERALLY SHOW DEWPOINTS IN THE MID 60S
TO NEAR 70F JUST SOUTH OF THE FRONT. THERE IS A CHANCE FOR AFTERNOON
SHOWERS AND STORMS TO DEVELOP IN THESE SOUTHERN ZONES IF THE TIMING
OF FROPA OCCURS LATE ENOUGH IN THE DAY TO COINCIDE WITH PEAK DIURNAL
HEATING.
SKIES WILL CLEAR FROM NORTH TO SOUTH BEHIND THE FRONT DURING THE
AFTERNOON. POST-FRONTAL AIRMASS OVER CENTRAL AND NORTHERN NJ AND
EASTERN PA WILL BE CHARACTERIZED BY NOTICEABLY DRIER AIR WITH
DEWPOINTS IN THE 50S.
THE COLD FRONT WILL STALL SOUTH OF THE AREA SUNDAY NIGHT INTO
MONDAY. ANY SHOWER ACTIVITY WITH THE FRONT WILL SUBSEQUENTLY SHIFT
SOUTH OF THE CWA. 00Z MODEL GUIDANCE COMING INTO SLIGHTLY BETTER
AGREEMENT WITH A WAVE OF LOPRES DEVELOPING OVER THE MIDWEST DURING
THIS TIME. THIS LOW IS THEN EXPECTED TO TRACK EASTWARD ALONG THE
STALLED BOUNDARY INTO THE MID-ATLANTIC REGION LATE MONDAY INTO
TUESDAY. THE PAST FEW RUNS OF THE ECMWF APPEARS TO BE SOUTHERN
OUTLIER WITH REGARDS TO THE TRACK OF THIS SYSTEM, KEEPING THE BULK
OF THE PRECIP SOUTH OF THE DELAWARE BAY WHILE MAJORITY OF OTHER 00Z
OPERATIONAL GUIDANCE EXHIBITS A MORE NORTHERN TRACK THAT GIVES A
PERIOD OF PRECIP TO JUST ABOUT THE ENTIRE AREA. HAVE CONFINED
MENTION OF THUNDER TO EXTREME SOUTHERN NJ ATTM, BUT TSTM CHANCES
WILL DEPEND ON HOW FAR NORTH WARM SECTOR ADVANCES.
THE LOW IS EXPECTED TO MOVE OFF THE MID-ATLANTIC COAST TUESDAY
AFTERNOON, ALLOWING FOR CLEARING SKIES FROM NORTHWEST TO SOUTHEAST
LATE IN THE DAY INTO TUESDAY NIGHT. DRY CONDITIONS EXPECTED
WEDNESDAY WITH WEAK HIPRES OVER THE AREA.
UPPER RIDGE BUILDS ACROSS THE SOUTHERN/CENTRAL CONUS TOWARD THE END
OF THE WEEK. THE MID-ATLANTIC REGION IS EXPECTED TO BE SITUATED TO
THE NORTHEAST OF THE RIDGE AT THE SAME TIME THAT THE UPPER TROUGH
LINGERS OVER THE NORTHEAST STATES. THE BELT OF STRONGER
WEST-NORTHWESTERLIES ALOFT WOULD BE FAVORED CLOSE TO THIS LATITUDE.
WOULD EXPECT A SOMEWHAT ACTIVE PATTERN WITH SEVERAL SHORTWAVE
DISTURBANCES TRACKING ACROSS THE AREA DURING THIS TIME. CHANCE POPS
ARE FORECAST FOR MOST OF THE CWA THURSDAY AND FRIDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE TODAY WITH A WIND GUST OR TO NOT OUT OF THE
QUESTION OVER 15KT. GIVEN MOST LOCATIONS ARE UNLIKELY TO
EXPERIENCE STRONG WIND GUSTS TODAY, LEFT OUT OF TAFS. WE WILL SEE MID
AND LEVEL HIGH CLOUDS CONTINUE TO MOVE IN FROM THE NORTHWEST AHEAD
OF A COLD FRONT THROUGH TONIGHT. CLOUDS SHOULD MAINLY BE FROM
5-10,000 FEET UP WITH MOSTLY CLOUDY CONDITIONS IN THE MORNING AS
THE FRONT PASSES THROUGH. A SHOWER OR RUMBLE OF THUNDER CAN NOT BE
RULED OUT LATE TONIGHT AND SUNDAY. HOWEVER, COVERAGE LOOKS TO BE
ISOLATED AND LEFT PRECIPITATION OUT OF TAFS AT ALL SITES. A BETTER
CHANCE FOR WIND GUSTS IS PRESENT SUNDAY AFTERNOON AND PLACED GUSTS
INTO THE TAF FOR PHL TOMORROW WITH TIMING FOCUSED AFTER 18Z.
OUTLOOK...
SUNDAY NIGHT THROUGH MONDAY- VFR AND DRY.
MONDAY NIGHT THROUGH TUESDAY- SHRA MOVE INTO THE AREA. LOCAL
VSBY/CIG RESTRICTIONS POSSIBLE, ESPECIALLY IN SRN TERMINALS.
TUESDAY NIGHT THROUGH WEDNESDAY- VFR.
&&
.MARINE...
SUB-SCA CONDITIONS EXPECTED ACROSS OUR WATERS TODAY AND TONIGHT.
WINDS WILL INCREASE THIS AFTERNOON FROM THE SOUTH BETWEEN 10-15
KNOTS AND SEAS WILL SLOWLY BUILD UPWARDS OF 3 FEET THROUGH SUNDAY
MORNING. LOWERED WAVE HEIGHTS SLIGHTLY WITH THE 12:30 PM UPDATE
BASED ON BUOY OBS.
OUTLOOK...
A COLD FRONT WILL MOVE THRU THE WATERS SUNDAY. SWLY WINDS AHEAD
OF THE FRONT WILL SHIFT OUT OF THE W-NW IN WAKE OF FROPA. WINDS
BELOW SCA THRESHOLD. A WAVE OF LOPRES TRACKS NEAR THE DELAWARE
WATERS MONDAY NIGHT AND TUESDAY. WINDS STRENGTHEN TO 15-20 KT
NORTH OF THE LOW TRACK TUESDAY AND WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLEIN
NEAR TERM...GAINES/HEAVENER
SHORT TERM...HEAVENER
LONG TERM...KLEIN
AVIATION...GAINES/HEAVENER/KLEIN
MARINE...GAINES/HEAVENER/KLEIN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1227 PM EDT SAT AUG 16 2014
.SYNOPSIS...
WEAK HIGH PRESSURE WILL INFLUENCE THE MID ATLANTIC TODAY. A COLD
FRONT WILL APPROACH FROM THE GREAT LAKES TONIGHT BEFORE MOVING
THROUGH THE AREA SUNDAY. THE FRONT WILL STALL TO THE SOUTH OF THE
AREA MONDAY. A WAVE OF LOW PRESSURE WILL TRACK ALONG THE FRONTAL
BOUNDARY AND ACROSS THE MID-ATLANTIC REGION MONDAY NIGHT AND
TUESDAY. HIGH PRESSURE RETURNS WEDNESDAY. HIGH PRESSURE WILL BECOME
ESTABLISHED ACROSS THE SOUTHERN AND CENTRAL UNITED STATES LATE IN
THE WEEK WHILE A SERIES OF DISTURBANCES TRACK AROUND THE NORTHERN
PERIPHERY OF THE HIGH AND THROUGH OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH THE 12:30 AM UPDATE MAXIMUM TEMPERATURES WERE LOWERED
SLIGHTLY AS SOME HIGH CLOUDS HAS PREVENTED MAXIMUM HEATING TODAY.
DEWPOINTS HAVE ALSO BEEN LOWERED SOME ACROSS THE 1-95 CORRIDOR IN
LINE WITH THE RECENT METAR OBS. THINK THE RAP IS OVERDONE WITH
SHOWERS DOWN SOUTH FOR THIS AFTERNOON AND HAVE REMOVED THIS
PRECIPITATION CHANCE FROM THE FORECAST.
THE MAJORITY OF THE REGION WILL STAY RAIN FREE TODAY WITH THE
ONLY EXCEPTION BEING EXTREME SOUTHERN DELMARVA. A WEAK MID- LEVEL
IMPULSE MOVING THROUGH OUR SOUTH, ALONG AN OLD FRONTAL BOUNDARY,
TOUCHED OFF A FEW SHOWERS IN SOUTHERN MARYLAND THAT WILL DRIFT
OVER EXTREME SOUTHERN DELMARVA THIS MORNING. ACROSS MOST OF THE
REGION SOUTHWEST WINDS WILL ALLOW FOR BETTER THERMAL ADVECTION
UNDER MOSTLY SUNNY SKIES AS THERE IS PLENTY OF DRY ALOFT TO MIX
DOWN.
TEMPERATURES WERE A BLEND OF THE MET/MAV GUIDANCE WITH A HEAVIER
WEIGHING TOWARDS THE COOLER MET TODAY. THE NAM INITIALIZED BETTER AT
850 AND 925MB COMPARED TO THE MAV, HENCE THE SLIGHT EDGE TOWARDS THE
MET.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
A SLOW MOVING COLD FRONT APPROACHES FROM THE NORTHWEST LATE TONIGHT
INTO SUNDAY. CONTINUED AIRMASS MODIFICATION TONIGHT, WITH DEWPOINTS
RISING TOWARDS 60F, COULD PROVIDE ENOUGH MOISTURE FOR THE
APPROACHING FRONT TO TAP INTO. THE BETTER FORCING LOOKS TO REMAIN
OUR NORTHWEST ZONES LATE TONIGHT BUT A FEW STRAY SHOWERS COULD DRIFT
ACROSS OUR NORTHERN ZONES BY TOMORROW MORNING...WE KEEP THE CHANCE
POPS GOING. OVERNIGHT LOWS WILL BE A FEW DEGREES WARMER THAN THIS
MORNING WITH THE WARMER STARTING POINT AND INCREASING CLOUD COVER
EXPECTED.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
ON SUNDAY, THE MID-ATLANTIC REGION WILL BE POSITIONED TOWARD THE
BASE OF AN UPPER TROUGH THAT IS ASSOCIATED WITH A CLOSED LOW OVER
EASTERN CANADA. 00Z MODEL GUIDANCE IN REASONABLY GOOD AGREEMENT WITH
THE SFC COLD FRONT MOVING THRU THE ERN PA/NJ SUNDAY MORNING. MAY SEE
A LINGERING SHOWER IN THE PA MTS TO START THE DAY. FARTHER EAST,
REMOVED MENTION OF SHOWERS WITH THE BEST UPPER FORCING FROM THE
TROUGH MOVING AWAY FROM THE AREA AND LLVL DOWNSLOPING/WLY FLOW
HELPING TO SCOUR OUT MOISTURE. HOWEVER, SRN PORTION OF THE FRONT IS
FORECAST TO GET HUNG UP OVER NERN MD INTO THE DELMARVA UNDER WEAKER
STEERING FLOW ALOFT. MODELS GENERALLY SHOW DEWPOINTS IN THE MID 60S
TO NEAR 70F JUST SOUTH OF THE FRONT. THERE IS A CHANCE FOR AFTERNOON
SHOWERS AND STORMS TO DEVELOP IN THESE SOUTHERN ZONES IF THE TIMING
OF FROPA OCCURS LATE ENOUGH IN THE DAY TO COINCIDE WITH PEAK DIURNAL
HEATING.
SKIES WILL CLEAR FROM NORTH TO SOUTH BEHIND THE FRONT DURING THE
AFTERNOON. POST-FRONTAL AIRMASS OVER CENTRAL AND NORTHERN NJ AND
EASTERN PA WILL BE CHARACTERIZED BY NOTICEABLY DRIER AIR WITH
DEWPOINTS IN THE 50S.
THE COLD FRONT WILL STALL SOUTH OF THE AREA SUNDAY NIGHT INTO
MONDAY. ANY SHOWER ACTIVITY WITH THE FRONT WILL SUBSEQUENTLY SHIFT
SOUTH OF THE CWA. 00Z MODEL GUIDANCE COMING INTO SLIGHTLY BETTER
AGREEMENT WITH A WAVE OF LOPRES DEVELOPING OVER THE MIDWEST DURING
THIS TIME. THIS LOW IS THEN EXPECTED TO TRACK EASTWARD ALONG THE
STALLED BOUNDARY INTO THE MID-ATLANTIC REGION LATE MONDAY INTO
TUESDAY. THE PAST FEW RUNS OF THE ECMWF APPEARS TO BE SOUTHERN
OUTLIER WITH REGARDS TO THE TRACK OF THIS SYSTEM, KEEPING THE BULK
OF THE PRECIP SOUTH OF THE DELAWARE BAY WHILE MAJORITY OF OTHER 00Z
OPERATIONAL GUIDANCE EXHIBITS A MORE NORTHERN TRACK THAT GIVES A
PERIOD OF PRECIP TO JUST ABOUT THE ENTIRE AREA. HAVE CONFINED
MENTION OF THUNDER TO EXTREME SOUTHERN NJ ATTM, BUT TSTM CHANCES
WILL DEPEND ON HOW FAR NORTH WARM SECTOR ADVANCES.
THE LOW IS EXPECTED TO MOVE OFF THE MID-ATLANTIC COAST TUESDAY
AFTERNOON, ALLOWING FOR CLEARING SKIES FROM NORTHWEST TO SOUTHEAST
LATE IN THE DAY INTO TUESDAY NIGHT. DRY CONDITIONS EXPECTED
WEDNESDAY WITH WEAK HIPRES OVER THE AREA.
UPPER RIDGE BUILDS ACROSS THE SOUTHERN/CENTRAL CONUS TOWARD THE END
OF THE WEEK. THE MID-ATLANTIC REGION IS EXPECTED TO BE SITUATED TO
THE NORTHEAST OF THE RIDGE AT THE SAME TIME THAT THE UPPER TROUGH
LINGERS OVER THE NORTHEAST STATES. THE BELT OF STRONGER
WEST-NORTHWESTERLIES ALOFT WOULD BE FAVORED CLOSE TO THIS LATITUDE.
WOULD EXPECT A SOMEWHAT ACTIVE PATTERN WITH SEVERAL SHORTWAVE
DISTURBANCES TRACKING ACROSS THE AREA DURING THIS TIME. CHANCE POPS
ARE FORECAST FOR MOST OF THE CWA THURSDAY AND FRIDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR. LIGHT AND VARIABLE WINDS TO START BECOMING
SOUTHWESTERLY 8-10 KNOTS. AFTERNOON STRATOCU DECK AROUND 4-5KFT.
TONIGHT...VFR. WINDS DECREASE AND REMAIN OUT OF THE SOUTHWEST. A FEW
SPOTTY SHOWERS ARE POSSIBLE NEAR RDG/ABE LATE TONIGHT. CONFIDENCE
LOW ON LOCATION SO LEFT OUT THEIR MENTION IN THE TAFS.
OUTLOOK...
SUNDAY- SLIGHT CHANCE OF A SHRA NEAR RDG/ABE IN THE MRNG. CHANCE
OF TSRA AS FAR NORTH OF AS ILG IN THE AFTN. MAINLY A VFR DAY.
SUNDAY NIGHT THROUGH MONDAY- VFR AND DRY.
MONDAY NIGHT THROUGH TUESDAY- SHRA MOVE INTO THE AREA. LOCAL
VSBY/CIG RESTRICTIONS POSSIBLE, ESPECIALLY IN SRN TERMINALS.
TUESDAY NIGHT THROUGH WEDNESDAY- VFR.
&&
.MARINE...
SUB-SCA CONDITIONS EXPECTED ACROSS OUR WATERS TODAY AND TONIGHT.
WINDS WILL INCREASE THIS AFTERNOON FROM THE SOUTH BETWEEN 10-15
KNOTS AND SEAS WILL SLOWLY BUILD UPWARDS OF 3 FEET THROUGH SUNDAY
MORNING. LOWERED WAVE HEIGHTS SLIGHTLY WITH THE 12:30 PM UPDATE
BASED ON BUOY OBS.
OUTLOOK...
A COLD FRONT WILL MOVE THRU THE WATERS SUNDAY. SWLY WINDS AHEAD
OF THE FRONT WILL SHIFT OUT OF THE W-NW IN WAKE OF FROPA. WINDS
BELOW SCA THRESHOLD. A WAVE OF LOPRES TRACKS NEAR THE DELAWARE
WATERS MONDAY NIGHT AND TUESDAY. WINDS STRENGTHEN TO 15-20 KT
NORTH OF THE LOW TRACK TUESDAY AND WEDNESDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLEIN
NEAR TERM...GAINES/HEAVENER
SHORT TERM...HEAVENER
LONG TERM...KLEIN
AVIATION...HEAVENER/KLEIN
MARINE...GAINES/HEAVENER/KLEIN
AREA FORECAST DISCUSSION
NWS MIAMI FL
1016 AM EDT SAT AUG 16 2014
.UPDATE...
DEEP LAYER RIDGE CONTINUES TO BE SUPPRESSED TO THE SOUTH AS A
LARGE SCALE MID LEVEL TROUGH REMAINS OVER THE NORTHEAST STATES.
THIS WILL MAINTAIN A SOUTHWEST TO WEST STEERING FLOW ACROSS SOUTH
FLORIDA AND THE 12Z MFL SOUNDING CONFIRMS THIS. THE ATMOSPHERIC
PROFILE ALSO LOOKS VERY SIMILAR TO YESTERDAY ALTHOUGH PWAT
ACTUALLY INCREASED BY JUST UNDER A QUARTER OF AN INCH TO NOW AN
EVEN TWO INCHES. MID LEVEL LAPSE RATES ALSO CONTINUE TO BE FAIRLY
IMPRESSIVE AT 6.2C/KM. ALL OF THIS SAID, THE INTERIOR AND EAST
COAST WILL BE THE MOST FAVORABLE FOR AFTERNOON THUNDERSTORMS WITH
POSSIBLE LOCALIZED URBAN STREET FLOODING ESPECIALLY ALONG THE EAST
COAST METRO AREAS AND WILL ADJUST THE POPS TO ACCOUNT FOR THIS.
THE HRRR IS ALSO SHOWING THIS PATTERN BUT FOR WHATEVER REASON THE
LATEST 11 AND 12Z RUNS HAVE BACKED OFF ON THE COVERAGE AND AM
HAVING A HARD TIME REASONING WITH A LESS CHANCE. THEREFORE, WILL
INCREASE THOSE CHANCES TO LIKELY FOR MOST OF THE INTERIOR AND EAST
COAST.
KOB
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
157 AM EDT SAT AUG 16 2014
.AVIATION...
THE WEATHER WILL BE MAINLY QUIET THROUGH ABOUT MID-MORNING, WHEN
CONVECTION IS EXPECTED TO DEVELOP ONCE AGAIN. AN ATLANTIC SEA
BREEZE SHOULD BEGIN TO PUSH INLAND AROUND 16Z, AND BECOME A
TRIGGER FOR SHOWERS AND STORMS. THERE IS SOME UNCERTAINTY AS TO
HOW FAR INLAND THE STORMS WILL OCCUR TODAY, SO KEPT THE VCTS IN
THE TAFS FOR NOW, RATHER THAN ADDING A PROB30 GROUP. CONVECTION
LOOKS TO CONTINUE THROUGH AROUND 23Z OR SO. OTHERWISE, VFR
CONDITIONS, EXCEPT BRIEF IFR POSSIBLE UNDER HEAVY SHOWERS.
&&
.PREV DISCUSSION... /ISSUED 807 PM EDT FRI AUG 15 2014/
AVIATION...54/BNB
PREV DISCUSSION... /ISSUED 750 PM EDT FRI AUG 15 2014/
UPDATE...STRONG THUNDERSTORMS WITH TORRENTIAL RAINS AFFECTED THE
EAST COAST EARLIER, BUT HAS SINCE ENDED. ADDITIONAL ACTIVITY IS
NOW MOVING IN FROM THE WEST...WITH THE STRONGEST STORMS OVER THE
GULF WATERS. ADJUSTED POPS/WEATHER BASED ON THESE TRENDS. ACTIVITY
WILL SLOWLY WANE WITH THE LOSS OF HEATING. /GREGORIA
PREV DISCUSSION... /ISSUED 313 PM EDT FRI AUG 15 2014/
DISCUSSION...
AS OF 1830Z...VERY ACTIVE CONVECTION ACROSS THE ATLANTIC COAST
AND THE ADJACENT ATLANTIC WATERS. VERY ACTIVE THUNDERSTORMS EXTEND
FROM NORTHEAST MIAMI DADE NORTHWARD THROUGH EASTERN BROWARD AND
PALM BEACH COUNTIES. THE LATEST HRRR MESO-SCALE MODEL GUIDANCE
WHICH INITIALIZED GENERALLY WELL ON THIS CONVECTION INDICATES
THIS ACTIVITY STARTING TO DISSIPATE AROUND 22Z. BUT AS ALWAYS WITH
EXISTING OUTFLOW BOUNDARIES ADDITIONAL CONVECTION COULD LINGER
INTO THE EARLY EVENING HOURS WITH THE CURRENT FORECAST INDICATING
ACTIVE CONVECTION WITH NUMEROUS SHOWERS/THUNDERSTORMS ACROSS THE
EASTERN HALF OF THE PENINSULA THROUGH 00Z THIS EVENING.
THE LATEST MODEL GUIDANCE INDICATES SOME RELATIVELY DRIER AIR
FORECAST TO MOVE NORTHWARD INTO THE FLORIDA STRAITS TONIGHT INTO
SATURDAY. HOWEVER...THE GUIDANCE INDICATES THAT IT MAY NOT MAKE IT
FAR ENOUGH NORTHWARD ON SATURDAY SUCH THAT LINGERING DEEP
MOISTURE OVER MOST OF THE PENINSULA AND ADJACENT WATERS COULD LEAD
TO ADDITIONAL AFTERNOON SHOWERS/THUNDERSTORMS ACROSS THE REGION
WITH THE SATURDAY FORECAST INDICATING THE GREATEST COVERAGE ACROSS
THE INTERIOR ALTHOUGH SCATTERED ACTIVITY IS FORECAST FOR THE GULF
AND ATLANTIC COAST METRO AREAS. BY SUNDAY THE GUIDANCE INDICATES
THAT THE DRIER AIR IS FORECAST TO CONTINUE MOVING NORTH WITH A
CONSIDERABLE REDUCTION ACROSS THE REGION IN SHOWERS/THUNDERSTORMS
WITH MAINLY THE INTERIOR REGIONS FORECAST TO HAVE SCATTERED
ACTIVITY.
THERE IS GUIDANCE SUGGESTING THAT SOME DUST ASSOCIATED WITH THE SAHARAN
AIR LAYER COULD ENTER THE REGION LATE SATURDAY INTO SUNDAY THEN
MOVE ACROSS THE REGION LATE SUNDAY AND PERSIST INTO EARLY NEXT
WEEK. SO THERE MAY BE NOTICEABLY HAZY SKIES SUNDAY INTO EARLY
NEXT WEEK.
MARINE...
LIGHT SOUTH TO SOUTHWEST WINDS ARE FORECAST ACROSS THE REGIONAL
WATERS TONIGHT THROUGH SATURDAY. BY SUNDAY WINDS ARE FORECAST TO
BECOME EAST TO SOUTHEAST WHILE REMAINING AROUND OR BELOW 10 KNOTS
AND PERSISTING INTO EARLY NEXT WEEK. REGIONAL SEAS ARE FORECAST TO
BE 2 FEET OR LESS THROUGH THE WEEKEND INTO AT LEAST EARLY NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 90 78 91 79 / 50 20 20 10
FORT LAUDERDALE 91 80 91 81 / 50 20 20 10
MIAMI 91 79 91 80 / 40 10 20 10
NAPLES 90 78 91 78 / 30 10 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...10/CD
LONG TERM....13/SI
AVIATION...13/SI
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
402 PM EDT SAT AUG 16 2014
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL REMAIN CENTERED SOUTH AND EAST OF THE
REGION THROUGH NEXT WEEK...WHILE A WEAK TROUGH OF LOW PRESSURE
PERSISTS INLAND. A COLD FRONT MAY APPROACH THE REGION LATE NEXT
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
REST OF THE AFTERNOON...SO FAR CONVECTION HAS BEEN ISOLATED IN
COVERAGE AND VERY WEAK...MAINLY CONFINED TO EASTERN CHARLESTON
COUNTY AROUND AWENDAW AND MCCLELLANVILLE. I HAVE MAINTAINED THE
CURRENT POP SCHEME AS RECENT RUNS OF THE RAP AND HRRR SHOW COVERAGE
INCREASING OVER THE NEXT COUPLE OF HOURS. THE THREAT FOR A COUPLE OF
STRONG TO SEVERE STORMS REMAINS AS DCAPES ARE GREATER THAN 1000 J/KG
THANKS TO MID LEVEL DRY AIR. DAMAGING WIND GUSTS AND LIGHTNING
REMAIN THE BIGGEST THREATS FROM ANY THUNDERSTORMS THAT DEVELOP.
TONIGHT...ANY LINGERING CONVECTION SHOULD DIMINISH QUICKLY WITH THE
LOSS OF HEATING THIS EVENING. UNLIKE PREVIOUS NIGHTS...MODELS SHOW
NO NOCTURNAL CONVECTION AND THE FORECAST IS DRY FOR THE OVERNIGHT.
THE PRESSURE GRADIENT WILL TIGHTEN A BIT OVERNIGHT AS WELL WHICH
WILL HELP MAINTAIN A LIGHT SOUTHWEST FLOW. SKIES WILL CLEAR OFF
THROUGH THE NIGHT AND MOST AREAS WILL BE MOSTLY CLEAR. LOWS WILL
RANGE FROM AROUND 70 INLAND TO THE MID/UPPER 70S ALONG THE COAST.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
ZONAL UPPER LEVEL FLOW WILL PERSIST THROUGH THE PERIOD. AT THE
SURFACE...ATLANTIC HIGH PRESSURE WILL REMAIN SOUTH AND EAST OF THE
REGION. THIS OVERALL PATTERN WILL RESULT IN DEEP WESTERLY FLOW AND
HOT TEMPERATURES...AT LEAST 3 TO 5 DEGS ABOVE NORMAL EACH DAY.
SUNDAY...THIS WILL BE THE DAY WITH THE LOWEST COVERAGE OF
CONVECTION...WITH PWS GENERALLY LESS THAN 1.5 INCHES AND MEAN RH
VALUES LESS THAN 50%. HAVE MAINTAINED SLIGHT CHANCE POPS FOR
AFTERNOON CONVECTION ALONG THE SEA BREEZE...WHICH SHOULD REMAIN OVER
THE EASTERN 1/3 OF THE AREA DUE TO BACKGROUND WEST-SOUTHWEST FLOW.
HIGH TEMPERATURES IN THE MID 90S. HEAT INDICES EXPECTED TO HOLD
AROUND 100 WITH SURFACE TDS EXPECTED TO MIX DOWN TO THE UPPER 60S TO
LOWER 70S BY AFTERNOON. ANY CONVECTION WILL DIE DOWN AFTER SUNSET
WITH LOWS IN THE MID 70S MOST AREAS.
MONDAY AND TUESDAY...HIGHER VALUES OF DEEP LAYER MOISTURE RETURNS IN
THE PERIOD WITH PWS AROUND 2 INCHES. LOW LEVEL FLOW WILL CONTINUE TO BE
WEST-SOUTHWEST...KEEPING ANY AFTERNOON SEA BREEZE PINNED WITH 10-15
MILES OF THE COAST. HAVE KEPT LOW END CHANCE POPS BOTH AFTERNOONS.
GLOBAL MODELS BOTH SHOW A WELL DEFINED ELONGATED UPPER VORTICITY
LOBE MOVING ACROSS THE AREA TUESDAY... WHICH MAY HELP TO INCREASE
COVERAGE MORE THAN MONDAY. IF THIS VORT LOBE CONTINUES TO BE SHOWN
BY THE MODELS ON TUESDAY...MAY NEED TO NUDGE POPS UP. HIGH
TEMPERATURES WILL CONTINUE HOT...IN THE MID TO POSSIBLY UPPER 90S.
AFTERNOON SURFACE TDS EXPECTED TO BE IN THE LOWER 70S...KEEPING HEAT
INDICES 103-106...BELOW HEAT ADVISORY CRITERIA. BOTH NIGHTS WILL
CONTINUE VERY WARM...IN THE MID TO UPPER 70S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A BROAD UPPER RIDGE WILL REMAIN IN PLACE TUESDAY NIGHT THROUGH
THURSDAY BEFORE RETROGRADING IN RESPONSE TO A DIGGING UPPER TROUGH
OVER THE MID-ATLANTIC REGION. WEDNESDAY AND THURSDAY WILL BE WARM
WITH HIGHS IN THE MIDDLE 90S. RAIN CHANCES LOOK LOW GIVEN THE MID
LEVEL CAPPING AND RATHER WEAK SEA BREEZE SO WE ARE ONLY CARRYING A
SLIGHT CHANCE POP. FRIDAY INTO SATURDAY ARE LESS CERTAIN DUE TO THE
POTENTIAL FOR A COLD FRONT TO DROP INTO THE AREA. MODELS ARE SPLIT
ON THE STRENGTH OF THE FRONT...THOUGH AT THIS POINT WE HAVE LOW END
POPS AND SLIGHTLY COOLER TEMPS.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
THE BIGGEST NEAR TERM FORECAST ISSUE IS THE POTENTIAL FOR
THUNDERSTORMS AT THE TERMINALS. THE BEST CHANCE APPEARS TO BE AT
KCHS AS THE SEA BREEZE PUSHES INLAND. HAVE ADDED A VCTS STARTING
AT 1930Z AND THEN A TEMPO FOR MVFR TS CONDITIONS BETWEEN 20Z-22Z.
OTHERWISE TAF/S ARE VFR. SOME LOW END POTENTIAL FOR LIGHT FOG
TONIGHT...BUT CONFIDENCE TOO LOW TO INCLUDE IN THE FORECAST.
EXTENDED AVIATION OUTLOOK...SUNDAY...MAINLY VFR. MONDAY-
FRIDAY...MORE TYPICAL SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS
EXPECTED...WITH VERY BRIEF PERIODS OF FLIGHT RESTRICTIONS POSSIBLE.
&&
.MARINE...
TONIGHT...THE PRESSURE GRADIENT WILL TIGHTEN UP A BIT OVERNIGHT WITH
A SURFACE TROUGH INLAND. THIS WILL RESULT IN A MODEST NOCTURNAL
SURGE. SOUTHWEST WINDS WILL INCREASE INTO THE 10-15 KT RANGE ACROSS
MOST OF THE WATERS...PERHAPS AS HIGH AS A SOLID 15 KT FOR THE OUTER
GEORGIA WATERS. SEAS ARE EXPECTED TO INCREASE INTO THE 2-3 FT RANGE
BY EARLY SUNDAY MORNING.
NO HIGHLIGHTS EXPECTED THROUGH THE PERIOD. ATLANTIC HIGH PRESSURE
WILL REMAIN CENTERED SOUTH AND EAST OF THE WATERS...WITH A TROUGH OF
LOWER PRESSURE INLAND. THIS WILL KEEP SOUTHWEST WINDS OF 15 KNOTS OR
LESS AND SEAS 3 FT OR LESS. EXPECT SOME NOCTURNAL SURGING EACH
EVENING THROUGH VERY EARLY MORNING...WITH WINDS OF 15-20 KTS.
&&
.EQUIPMENT...
THE CHARLESTON SC WSR-88D /KCLX/ REMAINS OUT OF SERVICE DUE TO A
SIGNIFICANT MECHANICAL FAILURE. REPAIR WORK CONTINUES AND THE
RADAR MAY BE OPERATIONAL AS EARLY AS AUGUST 20TH OR 21ST. UNTIL
THE RADAR IS RETURNED TO SERVICE...THE FOLLOWING RADARS CAN BE
USED: KJAX...KJGX...KVAX...KCAE AND KLTX.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...BSH
SHORT TERM...RFM
LONG TERM...JRL
AVIATION...BSH
MARINE...BSH/RFM
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
122 PM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 11Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA THROUGH 02Z.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING WITH THE WESTERLY COMPONENT TO THE LOW-
LEVEL FLOW SO FOG WILL LIKELY NOT BE AS EXTENSIVE AS WHAT
OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY AND SUNDAY NIGHT WITH
TEMPERATURES SUNDAY AFTERNOON A LITTLE ABOVE NORMAL IN THE MID
90S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ZONAL UPPER LEVEL FLOW ON MONDAY SLOWLY EVOLVES INTO NW FLOW ALOFT
BY THE END OF THE WEEK AS A RIDGE OF HIGH PRESSURE BUILDS JUST TO
OUR WEST. LOW LEVEL MOISTURE FLUX IS FROM THE WEST TO NORTHWEST
THROUGH THE PERIOD SO NOT A LOT OF MOISTURE TO SUPPORT
PRECIPITATION. MODELS INDICATE AN UPPER WAVE MOVING EAST OVER THE
AREA MONDAY AFTERNOON INTO TUESDAY WHICH MAY BE A FORCING
MECHANISM FOR CONVECTION. POPS ARE GENERALLY 10 TO 20 PERCENT AT
NIGHT AND 20 TO 30 PERCENT DURING THE DAY. TEMPS ABOVE NORMAL WITH
BUILDING RIDGE AND INSTABILITY MAY SUPPORT WIDELY SCATTERED MAINLY
DIURNAL CONVECTION. GFS SHOWS BACK DOOR FRONT NEXT SATURDAY BUT
THAT IS STILL A WAYS OFF.
&&
.AVIATION /17Z SATURDAY THROUGH WEDNESDAY/...
EXPECT MAINLY VFR CONDITIONS CONTINUING THROUGH THIS EVENING. ANY
THUNDERSTORMS SHOULD BE ISOLATED BECAUSE OF SHALLOW MOISTURE. THE
CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS
TIME. THE PRESSURE GRADIENT WILL BE WEAK AND THERE WILL BE
VARIABILITY IN THE WIND DIRECTION. NOCTURNAL COOLING AND LINGERING
LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY
MORNING. SOME DRYING WILL OCCUR IN THE WEST-SOUTHWEST LOW-LEVEL
FLOW. HOWEVER...FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE
GFS AND NAM MOS MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE
MODELS MAY BE TOO FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
108 PM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 11Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA THROUGH 02Z.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING SO THE FOG WILL LIKELY NOT BE AS EXTENSIVE
AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY AND SUNDAY NIGHT WITH
TEMPERATURES SUNDAY AFTERNOON A LITTLE ABOVE NORMAL IN THE MID
90S.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
ZONAL UPPER LEVEL FLOW ON MONDAY SLOWLY EVOLVES INTO NW FLOW ALOFT
BY THE END OF THE WEEK AS A RIDGE OF HIGH PRESSURE BUILDS JUST TO
OUR WEST. LOW LEVEL MOISTURE FLUX IS FROM THE WEST TO NORTHWEST
THROUGH THE PERIOD SO NOT A LOT OF MOISTURE TO SUPPORT
PRECIPITATION. MODELS INDICATE AN UPPER WAVE MOVING EAST OVER THE
AREA MONDAY AFTERNOON INTO TUESDAY WHICH MAY BE A FORCING
MECHANISM FOR CONVECTION. POPS ARE GENERALLY 10 TO 20 PERCENT AT
NIGHT AND 20 TO 30 PERCENT DURING THE DAY. TEMPS ABOVE NORMAL WITH
BUILDING RIDGE AND INSTABILITY MAY SUPPORT WIDELY SCATTERED MAINLY
DIURNAL CONVECTION. GFS SHOWS BACK DOOR FRONT NEXT SATURDAY BUT
THAT IS STILL A WAYS OFF.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
EXPECT MAINLY VFR CONDITIONS CONTINUING THROUGH THIS EVENING. ANY
THUNDERSTORMS SHOULD BE ISOLATED BECAUSE OF SHALLOW MOISTURE. THE
CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS
TIME. THE PRESSURE GRADIENT WILL BE WEAK AND THERE WILL BE
VARIABILITY IN THE WIND DIRECTION. NOCTURNAL COOLING AND LINGERING
LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY
MORNING. FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE GFS AND
NAM MOS MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE MODELS MAY
BE TOO FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1250 PM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 14Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING SO THE FOG WILL LIKELY NOT BE AS EXTENSIVE
AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY. FOR THE MOST PART SUNDAY
SHOULD BE A REPEAT OF SATURDAY...WITH MAINLY ISOLATED RAINFALL
ACROSS THE COASTAL PLAIN. OVERNIGHT LOWS TONIGHT WILL FALL TO
AROUND 70...WITH HIGHS ON SUNDAY IN THE LOWER TO MIDDLE 90S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
NO CHANGES MADE IN THE LONG TERM. THE GFS AND ECMWF DISPLAY
RIDGING EXTENDING FROM THE ATLANTIC WESTWARD NEAR THE GULF COAST
THROUGH THE MEDIUM- RANGE PERIOD. FARTHER NORTH THE MODELS SHOW
LEE-SIDE TROUGHING IN THE FORECAST AREA DURING MUCH OF THE PERIOD.
A FRONT DROPPING SOUTHWARD MAY EXTEND THROUGH THE FORECAST AREA
DURING PART OF THE PERIOD. THE RIDGE TO THE SOUTH SHOULD LIMIT
MOISTURE. THE MODELS SHOW STRONGER CONVERGENCE AND DEEPER MOISTURE
NORTH OF THE FORECAST AREA. THE GFS...ECMWF...AND EKD MOS HAVE
POPS 20 TO 30 PERCENT. EXPECT HIGH TEMPERATURES ABOVE NORMAL WITH
THE RIDGE TO THE SOUTH DIRECTING A WESTERLY FLOW INTO THE FORECAST
AREA. THE GUIDANCE HAS HIGHS MAINLY IN THE MIDDLE 90S THROUGH THE
PERIOD.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
EXPECT MAINLY VFR CONDITIONS CONTINUING THROUGH THIS EVENING. ANY
THUNDERSTORMS SHOULD BE ISOLATED BECAUSE OF SHALLOW MOISTURE. THE
CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS
TIME. THE PRESSURE GRADIENT WILL BE WEAK AND THERE WILL BE
VARIABILITY IN THE WIND DIRECTION. NOCTURNAL COOLING AND LINGERING
LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY
MORNING. FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE GFS AND
NAM MOS MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE MODELS MAY
BE TOO FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN...BUT STILL
WITH SOME DRYING THE FOG AND STRATUS LIKELY WILL NOT BE AS
EXTENSIVE COMPARED TO LAST NIGHT.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1124 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 11Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA THROUGH 02Z.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING SO THE FOG WILL LIKELY NOT BE AS EXTENSIVE
AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY. FOR THE MOST PART SUNDAY
SHOULD BE A REPEAT OF SATURDAY...WITH MAINLY ISOLATED RAINFALL
ACROSS THE COASTAL PLAIN. OVERNIGHT LOWS TONIGHT WILL FALL TO
AROUND 70...WITH HIGHS ON SUNDAY IN THE LOWER TO MIDDLE 90S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
NO CHANGES MADE IN THE LONG TERM. THE GFS AND ECMWF DISPLAY
RIDGING EXTENDING FROM THE ATLANTIC WESTWARD NEAR THE GULF COAST
THROUGH THE MEDIUM- RANGE PERIOD. FARTHER NORTH THE MODELS SHOW
LEE-SIDE TROUGHING IN THE FORECAST AREA DURING MUCH OF THE PERIOD.
A FRONT DROPPING SOUTHWARD MAY EXTEND THROUGH THE FORECAST AREA
DURING PART OF THE PERIOD. THE RIDGE TO THE SOUTH SHOULD LIMIT
MOISTURE. THE MODELS SHOW STRONGER CONVERGENCE AND DEEPER MOISTURE
NORTH OF THE FORECAST AREA. THE GFS...ECMWF...AND EKD MOS HAVE
POPS 20 TO 30 PERCENT. EXPECT HIGH TEMPERATURES ABOVE NORMAL WITH
THE RIDGE TO THE SOUTH DIRECTING A WESTERLY FLOW INTO THE FORECAST
AREA. THE GUIDANCE HAS HIGHS MAINLY IN THE MIDDLE 90S THROUGH THE
PERIOD.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
EXPECT MAINLY VFR CONDITIONS CONTINUING THROUGH THIS EVENING. ANY
THUNDERSTORMS SHOULD BE ISOLATED BECAUSE OF SHALLOW MOISTURE. THE
CHANCE IS TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS AT THIS
TIME. THE PRESSURE GRADIENT WILL BE WEAK AND THERE WILL BE
VARIABILITY IN THE WIND DIRECTION. NOCTURNAL COOLING AND LINGERING
LOW-LEVEL MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY
MORNING. FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE GFS AND
NAM MOS MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE MODELS MAY
BE TOO FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1118 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE THROUGH MONDAY. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...THE LATEST ANALYSIS INDICATED A WEAK PRESSURE PATTERN.
MOISTURE WAS SHALLOW. DESPITE STRONG HEATING THE THUNDERSTORM
CHANCE IS LOW BECAUSE OF LIMITED MOISTURE AND THE LACK OF A WELL-
DEFINED SURFACE FEATURE. BELIEVE ANY THUNDERSTORMS WILL BE
ISOLATED AND MAINLY CONFINED TO A FEW LOCATIONS IN THE EAST
SECTION OF THE FORECAST AREA WHERE DEWPOINT TEMPERATURES WERE
HIGHER. THE 11Z HRRR CONFINED THUNDERSTORMS TO NEAR THE SEA-BREEZE
FRONT AND JUST EAST OF THE FORECAST AREA THROUGH 02Z.
TONIGHT...THE SURFACE RIDGE TO OUR SOUTH WILL CONTINUE TO DOMINATE.
ANY THUNDERSTORMS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. THE TEMPERATURE GUIDANCE WAS CONSISTENT. LINGERING LOW-
LEVEL MOISTURE UNDER THE NOCTURNAL INVERSION MAY SUPPORT FOG. THE
MODELS INDICATE DRYING SO THE FOG WILL LIKELY NOT BE AS EXTENSIVE
AS WHAT OCCURRED LAST NIGHT. EXPECT PATCHY FOG.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
A DRY FORECAST IS ON TAP THROUGH SUNDAY. FOR THE MOST PART SUNDAY
SHOULD BE A REPEAT OF SATURDAY...WITH MAINLY ISOLATED RAINFALL
ACROSS THE COASTAL PLAIN. OVERNIGHT LOWS TONIGHT WILL FALL TO
AROUND 70...WITH HIGHS ON SUNDAY IN THE LOWER TO MIDDLE 90S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
NO CHANGES MADE IN THE LONG TERM. THE GFS AND ECMWF DISPLAY
RIDGING EXTENDING FROM THE ATLANTIC WESTWARD NEAR THE GULF COAST
THROUGH THE MEDIUM- RANGE PERIOD. FARTHER NORTH THE MODELS SHOW
LEE-SIDE TROUGHING IN THE FORECAST AREA DURING MUCH OF THE PERIOD.
A FRONT DROPPING SOUTHWARD MAY EXTEND THROUGH THE FORECAST AREA
DURING PART OF THE PERIOD. THE RIDGE TO THE SOUTH SHOULD LIMIT
MOISTURE. THE MODELS SHOW STRONGER CONVERGENCE AND DEEPER MOISTURE
NORTH OF THE FORECAST AREA. THE GFS...ECMWF...AND EKD MOS HAVE
POPS 20 TO 30 PERCENT. EXPECT HIGH TEMPERATURES ABOVE NORMAL WITH
THE RIDGE TO THE SOUTH DIRECTING A WESTERLY FLOW INTO THE FORECAST
AREA. THE GUIDANCE HAS HIGHS MAINLY IN THE MIDDLE 90S THROUGH THE
PERIOD.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
MUCH OF THE AREA HAD STRATUS AND FOG EARLY THIS MORNING. STRONG
HEATING SHOULD RESULT IN IMPROVING CONDITIONS LATER THIS MORNING.
USED THE GFS LAMP AND CONDITIONAL CLIMATOLOGY FOR THE TIMING OF
IMPROVEMENT LATER THIS MORNING. EXPECT MAINLY VFR CONDITIONS
CONTINUING THIS AFTERNOON AND EVENING. ANY THUNDERSTORMS SHOULD BE
ISOLATED BECAUSE OF SHALLOW MOISTURE. THE CHANCE IS TOO LOW TO
INCLUDE IN THE TERMINAL FORECASTS AT THIS TIME. THE PRESSURE
GRADIENT WILL BE WEAK TODAY AND THERE WILL BE VARIABILITY IN THE
WIND DIRECTION. NOCTURNAL COOLING AND LINGERING LOW-LEVEL
MOISTURE MAY SUPPORT STRATUS AND FOG AGAIN EARLY SUNDAY MORNING.
FORECASTED CONDITIONS MORE PESSIMISTIC THAN THE GFS AND NAM MOS
MAINLY BASED ON WHAT OCCURRED LAST NIGHT. THE MODELS MAY BE TOO
FAST WITH THE DRYING IN THIS WEAK FLOW PATTERN.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN
LATE NIGHT AND EARLY MORNING FOG. SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS ALSO MAY BRING RESTRICTIONS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
617 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM THE ATLANTIC WESTWARD ALONG THE GULF
COAST WILL DOMINATE DURING THE WEEKEND. THIS FEATURE WILL KEEP THE
FORECAST AREA MAINLY DRY WITH SEASONABLE TEMPERATURES.
&&
.NEAR TERM /TODAY/...
AFTER STARTING THE DAY WITH SOME STRATUS/FOG...SKIES WILL BECOME
PARTLY CLOUDY ONCE AGAIN. MODELS CONTINUE WITH WEAK SURFACE HIGH
ACROSS THE CWA...WITH WEAK TROUGHING ALONG THE COAST AND ALONG THE
REMNANTS OF AN OLD FRONTAL BOUNDARY SOUTH OF THE AREA. CAN NOT
RULE OUT AN ISOLATED SHOWER OR STORM IN A FEW AREAS LATE IN THE
AFTERNOON...BUT CONFIDENCE IS NOT HIGH ENOUGH TO WARRANT PLACING
IN THE FORECAST AT THIS TIME. BEST CHANCE WILL PROBABLY REMAIN
EAST OF THE CWA CLOSER TO THE COAST. AFTERNOON HIGHS WILL CLIMB
INTO THE LOWER 90S.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
ANY ISOLATED RAINFALL WILL DISSIPATE QUICKLY AFTER SUNSET...WITH
A DRY FORECAST ON TAP TONIGHT THROUGH SUNDAY. FOR THE MOST PART
SUNDAY SHOULD BE A REPEAT OF SATURDAY...WITH MAINLY ISOLATED
RAINFALL ACROSS THE COASTAL PLAIN. OVERNIGHT LOWS TONIGHT WILL
FALL TO AROUND 70...WITH HIGHS ON SUNDAY IN THE LOWER TO MIDDLE
90S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
NO CHANGES MADE IN THE LONG TERM. THE GFS AND ECMWF DISPLAY
RIDGING EXTENDING FROM THE ATLANTIC WESTWARD NEAR THE GULF COAST
THROUGH THE MEDIUM- RANGE PERIOD. FARTHER NORTH THE MODELS SHOW
LEE-SIDE TROUGHING IN THE FORECAST AREA DURING MUCH OF THE PERIOD.
A FRONT DROPPING SOUTHWARD MAY EXTEND THROUGH THE FORECAST AREA
DURING PART OF THE PERIOD. THE RIDGE TO THE SOUTH SHOULD LIMIT
MOISTURE. THE MODELS SHOW STRONGER CONVERGENCE AND DEEPER MOISTURE
NORTH OF THE FORECAST AREA. THE GFS...ECMWF...AND EKD MOS HAVE
POPS 20 TO 30 PERCENT. EXPECT HIGH TEMPERATURES ABOVE NORMAL WITH
THE RIDGE TO THE SOUTH DIRECTING A WESTERLY FLOW INTO THE FORECAST
AREA. THE GUIDANCE HAS HIGHS MAINLY IN THE MIDDLE 90S THROUGH THE
PERIOD.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
PERIODS OF MVFR/IFR CEILINGS EARLY THIS MORNING...THEN BECOMING VFR
CONDITIONS THROUGH THE REMAINDER OF THE DAY.
DEWPOINT TEMPERATURES ARE QUITE A BIT HIGHER THAN LAST NIGHT WITH
VALUES IN THE LOWER 70S. THIS WILL LEAD TO STRATUS/FOG FORMATION
IN MOST AREAS. HRRR MODEL SHOWS A MORE AGGRESSIVE FOG SCENARIO
THAN SOME OF THE OTHER MODELS. HAVE INCLUDED MVFR/IFR GROUP AT FOG
PRONE AGS/OGB...WITH SIMILAR CONDITIONS POSSIBLE AT OTHER TAF
SITES. STRATUS/FOG SHOULD BREAK UP BETWEEN 13Z AND 14Z. WINDS
WILL PICK UP DURING THE DAY FROM THE SOUTHWEST AT 5 TO 7 KNOTS OR
LESS.
EXTENDED AVIATION OUTLOOK...MVFR CONDITIONS POSSIBLE IN LATE
NIGHT/EARLY MORNING FOG EACH NIGHT. SCATTERED AFTERNOON/EVENING
SHOWERS AND THUNDERSTORMS POSSIBLE MONDAY AND TUESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
925 PM CDT SUN AUG 17 2014
.DISCUSSION...
925 PM CDT
AN AREA OF STRATUS ACROSS SOUTHERN LAKE MICHIGAN AND IMMEDIATE
ADJACENT AREAS OF ILLINOIS AND INDIANA MUCH OF TODAY HAS EXPANDED
RAPIDLY SINCE SUNDOWN AND LOOKS TO ENCOMPASS MUCH OF IF NOT THE
ENTIRE FORECAST AREA BY EARLY OVERNIGHT. THIS IS EXPANDING IN
LIGHT NORTHEAST WIND FLOW UNDERNEATH A STRENGTHENING INVERSION.
ALL IN ALL A SETUP THAT SHOULD FAVOR IT TO CONTINUE AND RAP
SOUNDINGS SUPPORT THIS. VISIBILITY HAS TEMPORARILY BEEN UNDER 1SM
AT VALPARAISO AND EARLIER AT MICHIGAN CITY. AREAS OF DENSE FOG
WILL BECOME PROGRESSIVELY MORE LIKELY AS THE NIGHT
PROGRESSES...ESPECIALLY THOSE NOT UNDER THE PRESENT STRATUS. WITH
THE LIGHT WIND REGIME FOG SHOULD BE SLOW TO IMPROVE EARLY MONDAY
MORNING...PROBABLY IMPACTING THE MORNING COMMUTE IN PLACES. WILL
CONTINUE TO MONITOR IF A DENSE FOG ADVISORY WILL BE NEEDED. FOR
NOW HAVE BEEFED UP DENSE WORDING IN THE FORECAST AND HIGHLIGHTED
WITH GRAPHICAL NOWCAST.
MTF/CMS
&&
.PREV DISCUSSION...
301 PM CDT
A WARMER...MORE HUMID...AND POTENTIALLY MORE UNSETTLED PATTERN IS ON
THE WAY FOR MUCH OF THE UPCOMING WEEK. MOISTURE CHANNEL IMAGERY
SHOWS THE UPPER LOW WHICH PROVIDED SOME SHOWER ACTIVITY YESTERDAY
MOVING MORE STEADILY ACROSS THE OHIO VALLEY. TO THE NORTH...A WAVE
IS MEANDERING EASTWARD ACROSS CENTRAL MINNESOTA WHILE A CLOSED UPPER
LOW SPINS OVER SOUTHERN MANITOBA. THIS TROUGH WILL DETERMINE THUNDER
CHANCES MONDAY NIGHT. ALSO OF NOTE IS A SERIES OF UPPER LOWS OVER
THE NORTHERN PACIFIC NEAR ALASKA. ENERGY FROM THESE SYSTEMS WILL
TRANSLATE INTO WESTERN/CENTRAL CANADA AND HELP FORCE UPPER RIDGING
OVER THE U.S. MIDWEST BRINGING THE AFOREMENTIONED WARM UP. AT THE
SURFACE...WEAK LOW PRESSURE IS OVER THE LOWER OHIO VALLEY IN
CONJUNCTION WITH THE UPPER LOW. ANOTHER WEAK LOW IS STRETCHED ACROSS
WESTERN MINNESOTA WHILE HIGH PRESSURE IS CENTERED OVER CENTRAL
ONTARIO. ANOTHER LOW IS OVER SOUTHERN MANITOBA IN CONJUNCTION WITH
THE BETTER ORGANIZED UPPER LOW IN THAT VICINITY.
TONIGHT...THE MAIN CONCERN TONIGHT WILL BE FOG/STRATUS AS RESIDUAL
LOW LEVEL MOISTURE LINGERS IN THE MIDST OF WEAK LOW LEVEL FLOW AND A
WEAK RIDGE AXIS. THE RIDGE AXIS WILL STRETCH ACROSS NORTHWEST AND
NORTH CENTRAL ILLINOIS BY MONDAY MORNING. WESTERN AREAS APPEAR TO BE
FAVORED FOR FOG DEVELOPMENT WHILE EASTERN AREAS MAY SEE MORE IN THE
WAY OF STRATUS...ESPECIALLY IF SOME EXISTING STRATUS IS UNABLE TO
ERODE INTO THE EVENING...ESPECIALLY NEAR THE LAKE. WILL INCLUDE FOG
MENTION IN THE FORECAST FOR MOST AREAS BUT THERE IS DECENT POTENTIAL
FOR DENSE FOG SO WILL NEED TO MONITOR THIS. WESTERN AREAS LOOK TO
HAVE THE BEST CHANCE FOR THIS AS THEY MAY CLEAR OUT THIS EVENING AND
BE IN CLOSEST PROXIMITY TO THE RIDGE AXIS.
MONDAY AND TUESDAY...THE UPPER WAVE OVER MINNESOTA WILL TRACK EAST
WITH ITS EFFECTS LARGELY STAYING TO THE NORTH OF THE AREA INTO
MONDAY MORNING...EXCEPT FOR SOME INCREASED MID AND HIGH LEVEL CLOUD
COVER. HOWEVER THE MANITOBA LOW WILL BE TRACKING EAST-SOUTHEAST
ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY MONDAY
BEFORE SLOWING OVER THE WESTERN GREAT LAKES MONDAY NIGHT. THIS WILL
PUSH ASCENT INTO THE AREA AS EARLY AS LATE MONDAY AFTERNOON IN THE
NORTHWEST BUT MORE LIKELY MONDAY EVENING INTO MONDAY NIGHT. A MORE
FOCUSED SURFACE TROUGH AXIS IS FORECAST TO CROSS THE AREA SOME TIME
EARLY TUESDAY BRINGING THE MOST FOCUSED CHANCE FOR SHOWERS AND
THUNDERSTORMS ESPECIALLY ACROSS CENTRAL AND NORTHERN AREAS. LATEST
FORECAST GUIDANCE SHOWS QUITE A BIT OF SPREAD IN TERMS OF TIMING OF
THE BEST FOCUS FOR PRECIP. WILL CARRY HIGHEST POPS MONDAY EVENING
AND OVERNIGHT WITH LOWER POPS LATER TUESDAY AS FOCUS IS LOST BUT
UPPER CYCLONIC FLOW CONTINUES AROUND THE STALLED UPPER LOW TO THE
NORTH FOR THE MORNING. SOME MODEST WARMING WILL OCCUR ALOFT MONDAY
BUT PERIODIC BOUTS OF MID CLOUD MAY HELP LIMIT TEMPS SOMEWHAT...NOT
TO MENTION IMPACT OF ANY MORNING STRATUS/FOG. FLOW WILL CONTINUE OFF
THE LAKE KEEPING LAKESHORE AREAS COOLEST. WILL CARRY HIGHS IN THE
LOW TO MID 70S LAKESIDE AND AROUND 80 INLAND MONDAY WITH SOUTH TO
SOUTHWEST WINDS TUESDAY ALLOWING TEMPS TO REACH THE LOWER 80S FOR
MOST PLACES UNLESS PRECIP TIMING SLOWS AND LINGERS THROUGH MORE OF
THE DAY.
WEDNESDAY INTO THE WEEKEND...A LARGER UPPER TROUGH WILL AMPLIFY OVER
WESTERN CANADA INTO WEDNESDAY AS ANOTHER UPPER LOW DROPS SOUTHWARD
DOWN THE CALIFORNIA COAST AND CUTS OFF. THIS WILL LEAD TO
AMPLIFICATION OF AN UPPER RIDGE ACROSS THE HIGH PLAINS TUESDAY WHICH
WILL QUICKLY SHIFT EAST INTO THE CENTRAL U.S. WEDNESDAY. THIS WILL
BRING A PUSH OF WARM ADVECTION ACROSS THE AREA WEDNESDAY WHICH MAY
BE ENOUGH TO KICK OFF SOME SHOWERS AND STORMS. WITH THE COMPLEX
TROUGH PATTERN TO THE WEST THERE WILL BE THE TENDENCY FOR SHORTWAVES
TO TRAVERSE THE RIDGE WITH SOME POTENTIAL FOR THIS TO BEGIN
WEDNESDAY BUT IT APPEARS MORE LIKELY TO BEGIN WEDNESDAY NIGHT. THE
RIDGE WILL PARK ITSELF OVER THE MIDWEST/WESTERN LAKES INTO FRIDAY
KEEPING THE LIKELIHOOD OF SHORTWAVES TRACKING THROUGH THE FLOW RATHER
HIGH. THE TRACK OF THESE WILL DEPEND ON HOW AMPLIFIED THE RIDGE
BECOMES BUT LATEST GUIDANCE CONTINUES TO KEEP THE LOCAL AREA IN A
FAVORED ZONE FOR THESE WAVES. THE AIRMASS WILL BECOME VERY MOIST BY
THURSDAY WITH PRECIPITABLE WATER VALUES PUSHING/TOPPING 2 INCHES.
BETWEEN THE POTENTIAL WAVES AND THE VERY MOIST AIRMASS SEVERAL
ROUNDS OF THUNDERSTORMS MAY AFFECT THE FORECAST AREA FROM LATER
WEDNESDAY THROUGH FRIDAY. IF THE AIRMASS BECOMES AS MOIST AS
EXPECTED THEN ANY STORM WILL HAVE A GOOD CHANCE TO BRING HEAVY
RAINFALL. RAINFALL POTENTIAL WILL NEED TO BE WATCHED CLOSELY OVER
THE NEXT SEVERAL DAYS ESPECIALLY IF MULTIPLE ROUNDS LOOK MORE
LIKELY. THIS RIDGE LOOKS TO AMPLIFY NORTHWARD SATURDAY PUSHING THE
FAVORED STORM TRACK TO THE NORTH. EVOLUTION BEYOND SATURDAY IS MORE
UNCERTAIN AND WILL BE DRIVEN BY THE MOVEMENT OF THE LARGE UPPER
TROUGH OVER NORTHERN U.S. AND CANADIAN ROCKIES. GUIDANCE IS IN
DISAGREEMENT ON HOW QUICKLY THIS OCCURS. OTHERWISE...HIGHS WILL WARM
FROM MIDWEEK INTO THE WEEKEND AS WILL HUMIDITY LEVELS. THE WILD CARD
WILL BE THUNDERSTORMS WITH THEIR TIMING AND LINGERING EFFECTS SUCH
AS CLOUD COVER PLAYING A KEY ROLE IN HOW WARM THINGS GET. MINIMAL
THUNDER IMPACT WOULD RESULT IN HIGHS IN THE MID AN UPPER 80S BY
THURSDAY WITH 90 POSSIBLE...ESPECIALLY IF THE RIDGE AMPLIFIES MORE
THAN CURRENTLY THOUGHT.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* LIFR CIGS INTO MONDAY MORNING.
* MVFR VISIBILITY SLOWLY DROPPING TO IFR WITH LIFR POSSIBLE BY
DAYBREAK.
* NORTHEAST WINDS BECOMING VARIABLE LATE TONIGHT.
* EAST WINDS ASSOCIATED WITH A LAKE BREEZE POSSIBLY APPROACHING 10
KT MONDAY AFTERNOON.
* CHANCE FOR SHRA LATE MONDAY EVENING INTO OVERNIGHT.
//DISCUSSION...UPDATED 03Z...
CIGS CONTINUE TO DETERIORATE AT A QUICK RATE WITH A WELL-DEFINED
AREA OF STRATUS EXPANDING WEST AND SOUTHWESTWARD ACROSS NORTHERN
IL AND NORTHWEST IN. SEE NO REASON WHY STRATUS WOULD IMPROVE
THROUGH 14Z WITH SOME GRADUAL LOWERING LIKELY. AS FOR
VISIBILITY...CONFIDENCE REMAINS LOW ON JUST HOW FAR THAT WILL
DROP. THE STRATUS MAY PREVENT FOG FROM BECOMING TOO DENSE AT
CHICAGOLAND AREA SITES...NAMELY ORD AND MDW...AS SLIGHTLY DRIER
AIR HAS ADVECTED IN AT THE IMMEDIATE SURFACE. THAT SAID...THE
STRATUS IS SO LOW ALREADY THAT IT MAY JUST ENCOMPASS THE GROUND
AS DENSE FOG BY DAYBREAK. THIS REMAINS MUCH MORE FAVORED AT
OUTLYING SITES INCLUDING RFD.
PREV DISCUSSION...UPDATED 00Z...
LATEST HAND SURFACE ANALYSIS SHOWS A STAGNANT WEATHER PATTERN
WHICH IS A RECIPE FOR LOW CLOUDS AND POTENTIALLY FOG TO BLOSSOM
AFTER DARK AGAIN TONIGHT. ONSHORE FLOW WILL LIKELY ADVECT LOW
CLOUDS SEEN ON CHICAGO WEBCAMS AND OBSERVED AT GYY INLAND TOWARD
ORD AND MDW AFTER SUNSET. THE MARINE LAYER ALSO IS CHARACTERIZED
BY LOWER VISIBILITY...THOUGH HOW LOW THAT WILL DROP IS A BIT
DIFFICULT TO DETERMINE. FURTHER AWAY FROM THE LAKE...FOR OUTLYING
AIRPORTS...FOG IS LIKELY TO DEVELOP DUE TO MOIST CONDITIONS /DEW
POINTS IN THE MID 60S/ AND DIMINISHING WIND FLOW.
OVERALL AT ALL TAF SITES...WIDESPREAD IFR TO LIFR CONDITIONS ARE
EXPECTED OVERNIGHT THROUGH AT LEAST 14Z MONDAY MORNING. SOME
SCATTERING IS EXPECTED BY AFTERNOON...BUT CONFIDENCE ON THAT IS
LOW...ALTHOUGH A LIFTING OF CLOUD BASES SHOULD OCCUR.
WINDS WILL CONTINUE AT 8-11 KT THROUGH 01Z AND MAYBE UNTIL 02Z
AT ORD AND MDW BASED ON OBSERVATIONAL TRENDS AND THE CONTINUED
ENHANCED LAKESIDE PRESSURE GRADIENT. SPEEDS WILL DIMINISH THROUGH
THE REMAINDER OF THE EVENING WITH VARIABILITY IN DIRECTION
THROUGH MONDAY MORNING. A LIGHT SOUTH TO SOUTHEAST WIND SHOULD
DEVELOP MONDAY AFTERNOON...WITH A LAKE BREEZE ANTICIPATED FOR
ORD...MDW...AND GYY DURING THE AFTERNOON.
LOW PRESSURE OVER MN ON MONDAY WILL APPROACH THE AREA MONDAY EVE
WITH A WSW LOW-LEVEL JET ADVECTING MOISTURE AND POSSIBLY
DEVELOPING SHOWERS BY LATER MONDAY EVE. BETTER CHANCES ARE
OVERNIGHT MONDAY...INCLUDING THE POSSIBILITY OF THUNDER.
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH IN LIFR CIGS THROUGH DAYBREAK. MEDIUM IN JUST HOW
LOW...WITH VV001 POSSIBLE.
* HIGH IN IFR VISIBILITY DEVELOPING BUT LOW ON WHETHER VISIBILITY
WILL DROP TO 1/2SM OR LESS.
* MEDIUM IN WIND SPEED MONDAY AND A SHIFT TO EAST OCCURRING.
* LOW IN SHOWER CHANCES PRIOR TO 06Z MONDAY EVENING.
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...TSRA LIKELY...ESPECIALLY DURING THE MORNING.
WEDNESDAY-SATURDAY...PERIODIC CHANCES OF TSRA.
MTF
&&
.MARINE...
150 PM CDT
A COLD FRONT HAS CLEARED THE SOUTHERN TIP OF THE LAKE...AND NORTH TO
NORTHEAST WINDS HAVE OVERSPREAD LAKE MICHIGAN WITH HIGH
PRESSURE OVER SOUTHERN ONTARIO AND LOW PRESSURE IN FAR SOUTHERN
ILLINOIS. EXPECT WAVES TO BUILD GENERALLY INTO THE 2 TO 4 FT
RANGE OVER THE SOUTHERN HALF OF THE LAKE BEFORE EASING SOME LATE
TONIGHT. BOTH THE CANADIAN HIGH AND THE LOW IN SOUTHERN ILLINOIS
WILL WORK THEIR WAY EASTWARD TONIGHT INTO MONDAY WHICH WILL
SLACKEN THE WINDS AND VEER THEM TO MORE OF AN EASTERLY DIRECTION
TONIGHT THAN SOUTH TO SOUTHEASTERLY ON MONDAY. ANOTHER WEAK LOW
PASSING THROUGH THE CANADIAN PRAIRIES WILL WORK ITS WAY SE TOWARD
THE NORTHERN HALF OF THE LAKE ON TUESDAY AND SLOWLY DRIFT EAST ON
WEDNESDAY. AFTER A PERIOD OF HIGH PRESSURE...A SERIES OF WEAK LOWS
WILL MIGRATE EASTWARD OUT OF THE PLAINS TOWARD THE LAKE FOR THE
LATTER HALF OF THE WEEK. KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM MONDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM MONDAY.
LM...NONE.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
902 PM CDT Sun Aug 17 2014
.UPDATE...
ISSUED AT 902 PM CDT SUN AUG 17 2014
Only a few remaining showers in SE Illinois this evening as lift
associated with the recent storm system diminishes as the low
moves off to the east. The air mass left behind in central/SE
Illinois remains quite moist at the surface with dewpoints in the
upper 60s to around 70 and near saturated conditions up to around
750 mb. Skies clearing above will allow for good radiational
cooling which will bring temperatures rapidly down to the
dewpoint. Fog will become prevalent overnight as a result.
Forecasts reflect this well, and will be keeping an eye on the
potential for dense fog formation. The mitigating factors are the
steady light northeast winds which will keep the surface layer
mixed, and the depth of the fog layer may preclude dense fog
formation later in the night. So far, updates have been sent to
account for trends on shower activity, temperature, humidity, and
winds and later updates may be sent as fog trends become more
definite.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 259 PM CDT SUN AUG 17 2014
Surface low has dropped into far southern Illinois early this
afternoon with remnant MCV still evident on radar imagery over the
far southeast CWA. This is where most of the lingering showers are
continuing, with a few as far north as Taylorville and Tuscola. Some
thinning of the low clouds has been developing but skies still
mainly cloudy.
Main concern for this part of the forecast is with fog potential
tonight. Cloudiness across far northern Illinois and southeast Iowa
is more cellular in nature and should diminish with loss of daytime
heating. Latest RAP guidance showing the northern CWA becoming
partly cloudy this evening. With northeast flow continuing, not a
lot of drying will take place in the lower levels with dew points
upstream still in the mid 60s in many areas. This should allow
visibilities to start dropping by late evening across the north.
Model guidance showing a fair range as to how extensive or thick the
fog gets, so for now will only mention patchy or areas of fog in the
grids for late tonight and early Monday. Skies expected to become
partly to mostly sunny by midday as forecast soundings are rather
dry.
In terms of the lingering showers, most of what`s left in our area
is along a weak trough axis dropping into southern Illinois, aided
by the upper low which is currently located in far southwest
Indiana. Am expecting the showers to fade early this evening as the
low pulls away. On Monday, have maintained some isolated showers/
storms across the eastern CWA during the afternoon as a weak wave
passes through the area.
&&
.LONG TERM...(Monday night through Sunday)
ISSUED AT 259 PM CDT SUN AUG 17 2014
Monday night will feature an upper trough and weak surface low
tracking from the upper midwest into the western Great Lakes, with a
cold front extending south into northern Illinois. Rain chances will
return to areas NW of the I-55 later Monday evening, with chances
expanding to Indiana along and north of I-72 by 12z/7am Tuesday.
Better forcing from the 500mb vort max should remain in northern IL,
but moisture convergence along the front and a weak 300mb jet max
overhead could provide just enough lift for a few storms with the
front. No severe weather is expected, especially with limited
instability overnight.
Tuesday should see a decreasing trend in rain/storm chances in the
afternoon as the bulk of the mid and upper level energy departs to
the east. The break in the rain should continue Tues night for all
but the far southwest KILX CWA, from Jacksonville to Effingham,
where a warm front will quickly approach the area. Rain/storm
chances will remain mainly southwest of Havana to Lincoln to
Shelbyville on Wednesday as the front slowly pushes into IL.
That warm front is expected to usher in a progressively warmer
airmass the remainder of the week and into the weekend. Wednesday
night, an MCV is projected to move from N Iowa across N Illinois,
with enough support from strong mid level warm air advection and a
low level jet across central IL to trigger showers/storms across most
of our forecast area.
Low surface pressure and a stalled frontal boundary are still
expected across northern Illinois for Thursday, keeping rain chances
going into Thursday night. The front is expected wash out Thursday
night as warming continues through a deep layer of the atmosphere.
The warming at mid levels will eventually work to cap the atmosphere
and limit storm potential, despite ample low level moisture. A
shortwave is forecast by the ECMWF to move from Nebraska across N
Illinois Saturday, which could affect our northern counties with a
few storms, depending on the extent of elevated CAPE above the
capping inversion.
The ECMWF is also showing a cold frontal passage following the
shortwave on Saturday night, bringing a period of storms and
slightly cooler air for Sunday. The GFS keeps the upper level ridge
entrenched over IL, limiting much storm potential by keeping
shortwave tracks north of central IL. It also has much warmer
conditions continuing into Sunday. Confidence remains low on the
scenario for next weekend due to the differences.
Heat and humidity levels will climb the last half of the week, as
highs reach into the lower 90s south of Lincoln to Mattoon Thurs
through Saturday. Dewpoints in the low to mid 70s will help push
heat index readings into the upper 90s to around 100 in at least the
south half of the KILX CWA.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 650 PM CDT SUN AUG 17 2014
Most of central IL has returned to VFR conditions this evening as
MVFR ceilings that were prevalent earlier have lifted and
scattered out. MVFR ceilings remain prevalent in southeast IL.
This evening, isolated showers will diminish while partial
clearing takes place for several hours. Overnight, fog will
develop, with potential for LIFR or VLIFR conditions...mainly 04Z-
15Z. Improving conditions after 15Z with ceilings becoming sct-
bkn030 for most of the afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ONTON
SHORT TERM...GEELHART
LONG TERM...SHIMON
AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
653 PM CDT SUN AUG 17 2014
.DISCUSSION...
301 PM CDT
A WARMER...MORE HUMID...AND POTENTIALLY MORE UNSETTLED PATTERN IS ON
THE WAY FOR MUCH OF THE UPCOMING WEEK. MOISTURE CHANNEL IMAGERY
SHOWS THE UPPER LOW WHICH PROVIDED SOME SHOWER ACTIVITY YESTERDAY
MOVING MORE STEADILY ACROSS THE OHIO VALLEY. TO THE NORTH...A WAVE
IS MEANDERING EASTWARD ACROSS CENTRAL MINNESOTA WHILE A CLOSED UPPER
LOW SPINS OVER SOUTHERN MANITOBA. THIS TROUGH WILL DETERMINE THUNDER
CHANCES MONDAY NIGHT. ALSO OF NOTE IS A SERIES OF UPPER LOWS OVER
THE NORTHERN PACIFIC NEAR ALASKA. ENERGY FROM THESE SYSTEMS WILL
TRANSLATE INTO WESTERN/CENTRAL CANADA AND HELP FORCE UPPER RIDGING
OVER THE U.S. MIDWEST BRINGING THE AFOREMENTIONED WARM UP. AT THE
SURFACE...WEAK LOW PRESSURE IS OVER THE LOWER OHIO VALLEY IN
CONJUNCTION WITH THE UPPER LOW. ANOTHER WEAK LOW IS STRETCHED ACROSS
WESTERN MINNESOTA WHILE HIGH PRESSURE IS CENTERED OVER CENTRAL
ONTARIO. ANOTHER LOW IS OVER SOUTHERN MANITOBA IN CONJUNCTION WITH
THE BETTER ORGANIZED UPPER LOW IN THAT VICINITY.
TONIGHT...THE MAIN CONCERN TONIGHT WILL BE FOG/STRATUS AS RESIDUAL
LOW LEVEL MOISTURE LINGERS IN THE MIDST OF WEAK LOW LEVEL FLOW AND A
WEAK RIDGE AXIS. THE RIDGE AXIS WILL STRETCH ACROSS NORTHWEST AND
NORTH CENTRAL ILLINOIS BY MONDAY MORNING. WESTERN AREAS APPEAR TO BE
FAVORED FOR FOG DEVELOPMENT WHILE EASTERN AREAS MAY SEE MORE IN THE
WAY OF STRATUS...ESPECIALLY IF SOME EXISTING STRATUS IS UNABLE TO
ERODE INTO THE EVENING...ESPECIALLY NEAR THE LAKE. WILL INCLUDE FOG
MENTION IN THE FORECAST FOR MOST AREAS BUT THERE IS DECENT POTENTIAL
FOR DENSE FOG SO WILL NEED TO MONITOR THIS. WESTERN AREAS LOOK TO
HAVE THE BEST CHANCE FOR THIS AS THEY MAY CLEAR OUT THIS EVENING AND
BE IN CLOSEST PROXIMITY TO THE RIDGE AXIS.
MONDAY AND TUESDAY...THE UPPER WAVE OVER MINNESOTA WILL TRACK EAST
WITH ITS EFFECTS LARGELY STAYING TO THE NORTH OF THE AREA INTO
MONDAY MORNING...EXCEPT FOR SOME INCREASED MID AND HIGH LEVEL CLOUD
COVER. HOWEVER THE MANITOBA LOW WILL BE TRACKING EAST-SOUTHEAST
ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY MONDAY
BEFORE SLOWING OVER THE WESTERN GREAT LAKES MONDAY NIGHT. THIS WILL
PUSH ASCENT INTO THE AREA AS EARLY AS LATE MONDAY AFTERNOON IN THE
NORTHWEST BUT MORE LIKELY MONDAY EVENING INTO MONDAY NIGHT. A MORE
FOCUSED SURFACE TROUGH AXIS IS FORECAST TO CROSS THE AREA SOME TIME
EARLY TUESDAY BRINGING THE MOST FOCUSED CHANCE FOR SHOWERS AND
THUNDERSTORMS ESPECIALLY ACROSS CENTRAL AND NORTHERN AREAS. LATEST
FORECAST GUIDANCE SHOWS QUITE A BIT OF SPREAD IN TERMS OF TIMING OF
THE BEST FOCUS FOR PRECIP. WILL CARRY HIGHEST POPS MONDAY EVENING
AND OVERNIGHT WITH LOWER POPS LATER TUESDAY AS FOCUS IS LOST BUT
UPPER CYCLONIC FLOW CONTINUES AROUND THE STALLED UPPER LOW TO THE
NORTH FOR THE MORNING. SOME MODEST WARMING WILL OCCUR ALOFT MONDAY
BUT PERIODIC BOUTS OF MID CLOUD MAY HELP LIMIT TEMPS SOMEWHAT...NOT
TO MENTION IMPACT OF ANY MORNING STRATUS/FOG. FLOW WILL CONTINUE OFF
THE LAKE KEEPING LAKESHORE AREAS COOLEST. WILL CARRY HIGHS IN THE
LOW TO MID 70S LAKESIDE AND AROUND 80 INLAND MONDAY WITH SOUTH TO
SOUTHWEST WINDS TUESDAY ALLOWING TEMPS TO REACH THE LOWER 80S FOR
MOST PLACES UNLESS PRECIP TIMING SLOWS AND LINGERS THROUGH MORE OF
THE DAY.
WEDNESDAY INTO THE WEEKEND...A LARGER UPPER TROUGH WILL AMPLIFY OVER
WESTERN CANADA INTO WEDNESDAY AS ANOTHER UPPER LOW DROPS SOUTHWARD
DOWN THE CALIFORNIA COAST AND CUTS OFF. THIS WILL LEAD TO
AMPLIFICATION OF AN UPPER RIDGE ACROSS THE HIGH PLAINS TUESDAY WHICH
WILL QUICKLY SHIFT EAST INTO THE CENTRAL U.S. WEDNESDAY. THIS WILL
BRING A PUSH OF WARM ADVECTION ACROSS THE AREA WEDNESDAY WHICH MAY
BE ENOUGH TO KICK OFF SOME SHOWERS AND STORMS. WITH THE COMPLEX
TROUGH PATTERN TO THE WEST THERE WILL BE THE TENDENCY FOR SHORTWAVES
TO TRAVERSE THE RIDGE WITH SOME POTENTIAL FOR THIS TO BEGIN
WEDNESDAY BUT IT APPEARS MORE LIKELY TO BEGIN WEDNESDAY NIGHT. THE
RIDGE WILL PARK ITSELF OVER THE MIDWEST/WESTERN LAKES INTO FRIDAY
KEEPING THE LIKELIHOOD OF SHORTWAVES TRACKING THROUGH THE FLOW RATHER
HIGH. THE TRACK OF THESE WILL DEPEND ON HOW AMPLIFIED THE RIDGE
BECOMES BUT LATEST GUIDANCE CONTINUES TO KEEP THE LOCAL AREA IN A
FAVORED ZONE FOR THESE WAVES. THE AIRMASS WILL BECOME VERY MOIST BY
THURSDAY WITH PRECIPITABLE WATER VALUES PUSHING/TOPPING 2 INCHES.
BETWEEN THE POTENTIAL WAVES AND THE VERY MOIST AIRMASS SEVERAL
ROUNDS OF THUNDERSTORMS MAY AFFECT THE FORECAST AREA FROM LATER
WEDNESDAY THROUGH FRIDAY. IF THE AIRMASS BECOMES AS MOIST AS
EXPECTED THEN ANY STORM WILL HAVE A GOOD CHANCE TO BRING HEAVY
RAINFALL. RAINFALL POTENTIAL WILL NEED TO BE WATCHED CLOSELY OVER
THE NEXT SEVERAL DAYS ESPECIALLY IF MULTIPLE ROUNDS LOOK MORE
LIKELY. THIS RIDGE LOOKS TO AMPLIFY NORTHWARD SATURDAY PUSHING THE
FAVORED STORM TRACK TO THE NORTH. EVOLUTION BEYOND SATURDAY IS MORE
UNCERTAIN AND WILL BE DRIVEN BY THE MOVEMENT OF THE LARGE UPPER
TROUGH OVER NORTHERN U.S. AND CANADIAN ROCKIES. GUIDANCE IS IN
DISAGREEMENT ON HOW QUICKLY THIS OCCURS. OTHERWISE...HIGHS WILL WARM
FROM MIDWEEK INTO THE WEEKEND AS WILL HUMIDITY LEVELS. THE WILD CARD
WILL BE THUNDERSTORMS WITH THEIR TIMING AND LINGERING EFFECTS SUCH
AS CLOUD COVER PLAYING A KEY ROLE IN HOW WARM THINGS GET. MINIMAL
THUNDER IMPACT WOULD RESULT IN HIGHS IN THE MID AN UPPER 80S BY
THURSDAY WITH 90 POSSIBLE...ESPECIALLY IF THE RIDGE AMPLIFIES MORE
THAN CURRENTLY THOUGHT.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* BROKEN CIGS OF 1000-1500 FT WITH TEMPORARY SCATTERING THROUGH
SUNDOWN...THEN DROPPING BACK TO IFR AND EVENTUAL LIFR THROUGH
THE REST OF TONIGHT.
* PROBABLE IFR VISBY AND LIFR CIGS DURING AT LEAST A GOOD PART OF
THE MONDAY MORNING RUSH.
* NORTHEAST WINDS AROUND 10KT THROUGH 01Z-02Z.
* EAST WINDS ASSOCIATED WITH A LAKE BREEZE POSSIBLY APPROACHING 10
KT MONDAY AFTERNOON.
* CHANCE FOR SHRA LATE MONDAY EVENING INTO OVERNIGHT.
//DISCUSSION...UPDATED 00Z...
LATEST HAND SURFACE ANALYSIS SHOWS A STAGNANT WEATHER PATTERN
WHICH IS A RECIPE FOR LOW CLOUDS AND POTENTIALLY FOG TO BLOSSOM
AFTER DARK AGAIN TONIGHT. ONSHORE FLOW WILL LIKELY ADVECT LOW
CLOUDS SEEN ON CHICAGO WEBCAMS AND OBSERVED AT GYY INLAND TOWARD
ORD AND MDW AFTER SUNSET. THE MARINE LAYER ALSO IS CHARACTERIZED
BY LOWER VISIBILITY...THOUGH HOW LOW THAT WILL DROP IS A BIT
DIFFICULT TO DETERMINE. FURTHER AWAY FROM THE LAKE...FOR OUTLYING
AIRPORTS...FOG IS LIKELY TO DEVELOP DUE TO MOIST CONDITIONS /DEW
POINTS IN THE MID 60S/ AND DIMINISHING WIND FLOW.
OVERALL AT ALL TAF SITES...WIDESPREAD IFR TO LIFR CONDITIONS ARE
EXPECTED OVERNIGHT THROUGH AT LEAST 14Z MONDAY MORNING. SOME
SCATTERING IS EXPECTED BY AFTERNOON...BUT CONFIDENCE ON THAT IS
LOW...ALTHOUGH A LIFTING OF CLOUD BASES SHOULD OCCUR.
WINDS WILL CONTINUE AT 8-11 KT THROUGH 01Z AND MAYBE UNTIL 02Z
AT ORD AND MDW BASED ON OBSERVATIONAL TRENDS AND THE CONTINUED
ENHANCED LAKESIDE PRESSURE GRADIENT. SPEEDS WILL DIMINISH THROUGH
THE REMAINDER OF THE EVENING WITH VARIABILITY IN DIRECTION
THROUGH MONDAY MORNING. A LIGHT SOUTH TO SOUTHEAST WIND SHOULD
DEVELOP MONDAY AFTERNOON...WITH A LAKE BREEZE ANTICIPATED FOR
ORD...MDW...AND GYY DURING THE AFTERNOON.
LOW PRESSURE OVER MN ON MONDAY WILL APPROACH THE AREA MONDAY EVE
WITH A WSW LOW-LEVEL JET ADVECTING MOISTURE AND POSSIBLY
DEVELOPING SHOWERS BY LATER MONDAY EVE. BETTER CHANCES ARE
OVERNIGHT MONDAY...INCLUDING THE POSSIBILITY OF THUNDER.
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH IN IFR CIGS RETURNING BY 04Z...BUT COULD BE EVEN EARLIER.
* HIGH IN AT LEAST IFR CIGS TO START THE MONDAY MORNING RUSH.
MEDIUM IN LIFR CIGS AND IFR VISIBILITY. LOW IN IMPROVEMENT TIME.
* HIGH IN WIND DIRECTION AND MEDIUM IN WIND SPEED TONIGHT.
* MEDIUM IN WIND MONDAY AND A SHIFT TO EAST OCCURRING.
* LOW IN SHOWER CHANCES PRIOR TO 06Z MONDAY EVENING.
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...TSRA LIKELY...ESPECIALLY DURING THE MORNING.
WEDNESDAY-SATURDAY...PERIODIC CHANCES OF TSRA.
MTF
&&
.MARINE...
150 PM CDT
A COLD FRONT HAS CLEARED THE SOUTHERN TIP OF THE LAKE...AND NORTH TO
NORTHEAST WINDS HAVE OVERSPREAD LAKE MICHIGAN WITH HIGH
PRESSURE OVER SOUTHERN ONTARIO AND LOW PRESSURE IN FAR SOUTHERN
ILLINOIS. EXPECT WAVES TO BUILD GENERALLY INTO THE 2 TO 4 FT
RANGE OVER THE SOUTHERN HALF OF THE LAKE BEFORE EASING SOME LATE
TONIGHT. BOTH THE CANADIAN HIGH AND THE LOW IN SOUTHERN ILLINOIS
WILL WORK THEIR WAY EASTWARD TONIGHT INTO MONDAY WHICH WILL
SLACKEN THE WINDS AND VEER THEM TO MORE OF AN EASTERLY DIRECTION
TONIGHT THAN SOUTH TO SOUTHEASTERLY ON MONDAY. ANOTHER WEAK LOW
PASSING THROUGH THE CANADIAN PRAIRIES WILL WORK ITS WAY SE TOWARD
THE NORTHERN HALF OF THE LAKE ON TUESDAY AND SLOWLY DRIFT EAST ON
WEDNESDAY. AFTER A PERIOD OF HIGH PRESSURE...A SERIES OF WEAK LOWS
WILL MIGRATE EASTWARD OUT OF THE PLAINS TOWARD THE LAKE FOR THE
LATTER HALF OF THE WEEK. KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM MONDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM MONDAY.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
651 PM CDT Sun Aug 17 2014
.SHORT TERM...(This evening through Monday)
ISSUED AT 259 PM CDT SUN AUG 17 2014
Surface low has dropped into far southern Illinois early this
afternoon with remnant MCV still evident on radar imagery over the
far southeast CWA. This is where most of the lingering showers are
continuing, with a few as far north as Taylorville and Tuscola. Some
thinning of the low clouds has been developing but skies still
mainly cloudy.
Main concern for this part of the forecast is with fog potential
tonight. Cloudiness across far northern Illinois and southeast Iowa
is more cellular in nature and should diminish with loss of daytime
heating. Latest RAP guidance showing the northern CWA becoming
partly cloudy this evening. With northeast flow continuing, not a
lot of drying will take place in the lower levels with dew points
upstream still in the mid 60s in many areas. This should allow
visibilities to start dropping by late evening across the north.
Model guidance showing a fair range as to how extensive or thick the
fog gets, so for now will only mention patchy or areas of fog in the
grids for late tonight and early Monday. Skies expected to become
partly to mostly sunny by midday as forecast soundings are rather
dry.
In terms of the lingering showers, most of what`s left in our area
is along a weak trough axis dropping into southern Illinois, aided
by the upper low which is currently located in far southwest
Indiana. Am expecting the showers to fade early this evening as the
low pulls away. On Monday, have maintained some isolated showers/
storms across the eastern CWA during the afternoon as a weak wave
passes through the area.
&&
.LONG TERM...(Monday night through Sunday)
ISSUED AT 259 PM CDT SUN AUG 17 2014
Monday night will feature an upper trough and weak surface low
tracking from the upper midwest into the western Great Lakes, with a
cold front extending south into northern Illinois. Rain chances will
return to areas NW of the I-55 later Monday evening, with chances
expanding to Indiana along and north of I-72 by 12z/7am Tuesday.
Better forcing from the 500mb vort max should remain in northern IL,
but moisture convergence along the front and a weak 300mb jet max
overhead could provide just enough lift for a few storms with the
front. No severe weather is expected, especially with limited
instability overnight.
Tuesday should see a decreasing trend in rain/storm chances in the
afternoon as the bulk of the mid and upper level energy departs to
the east. The break in the rain should continue Tues night for all
but the far southwest KILX CWA, from Jacksonville to Effingham,
where a warm front will quickly approach the area. Rain/storm
chances will remain mainly southwest of Havana to Lincoln to
Shelbyville on Wednesday as the front slowly pushes into IL.
That warm front is expected to usher in a progressively warmer
airmass the remainder of the week and into the weekend. Wednesday
night, an MCV is projected to move from N Iowa across N Illinois,
with enough support from strong mid level warm air advection and a
low level jet across central IL to trigger showers/storms across most
of our forecast area.
Low surface pressure and a stalled frontal boundary are still
expected across northern Illinois for Thursday, keeping rain chances
going into Thursday night. The front is expected wash out Thursday
night as warming continues through a deep layer of the atmosphere.
The warming at mid levels will eventually work to cap the atmosphere
and limit storm potential, despite ample low level moisture. A
shortwave is forecast by the ECMWF to move from Nebraska across N
Illinois Saturday, which could affect our northern counties with a
few storms, depending on the extent of elevated CAPE above the
capping inversion.
The ECMWF is also showing a cold frontal passage following the
shortwave on Saturday night, bringing a period of storms and
slightly cooler air for Sunday. The GFS keeps the upper level ridge
entrenched over IL, limiting much storm potential by keeping
shortwave tracks north of central IL. It also has much warmer
conditions continuing into Sunday. Confidence remains low on the
scenario for next weekend due to the differences.
Heat and humidity levels will climb the last half of the week, as
highs reach into the lower 90s south of Lincoln to Mattoon Thurs
through Saturday. Dewpoints in the low to mid 70s will help push
heat index readings into the upper 90s to around 100 in at least the
south half of the KILX CWA.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 650 PM CDT SUN AUG 17 2014
Most of central IL has returned to VFR conditions this evening as
MVFR ceilings that were prevalent earlier have lifted and
scattered out. MVFR ceilings remain prevalent in southeast IL.
This evening, isolated showers will diminish while partial
clearing takes place for several hours. Overnight, fog will
develop, with potential for LIFR or VLIFR conditions...mainly 04Z-
15Z. Improving conditions after 15Z with ceilings becoming sct-
bkn030 for most of the afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEELHART
LONG TERM...SHIMON
AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
101 PM CDT SAT AUG 16 2014
.DISCUSSION...
339 AM CDT
SHORT TERM...THROUGH SATURDAY NIGHT...
FOR THE REMAINDER OF THE NIGHT AND INTO SATURDAY MORNING...HIGH
PRESSURE CONTINUES TO SLIDE SOUTHEAST INTO THE CENTRAL APPALACHIANS
WITH A RIDGE AXIS EXTENDING NORTHWEST INTO SOUTHERN MINNESOTA. LOW
PRESSURE MOVING THROUGH ONTARIO IS DRAGGING A COLD FRONT INTO THE
UPPER GREAT LAKES REGION. WITH CLEAR SKIES AND LIGHT WINDS UNDER
THE RIDGE AXIS...SOME PATCHY FOG IS FORMING OVER NWRN AND NCNTRL IL
WHERE TEMPERATURES HAVE BEEN ABLE TO RADIATE LOWER AND A RETURN FLOW
OF MOISTURE AROUND THE WESTERN PERIPHERY OF THE HIGH HAS RAISED
DEWPOINTS INTO UPPER 50S. THE PATCHY FOG MAY INCREASE IN COVERAGE
THROUGH THE REMAINDER OF THE LATE NIGHT HOURS...BUT DO NOT
ANTICIPATE WIDESPREAD DENSE FOG.
INTO THE MORNING HOURS...THE INITIAL CONCERN WILL BE THE SPREAD OF
SHRA/TSRA INTO WEST CENTRAL IL ASSOCIATED WITH A VERY SLOW MOVING
SHORTWAVE OVER SCNTRL IA/NCNTRL MO. THE TREND OF THIS SYSTEM HAS
BEEN ON A MORE SOUTHERLY TRACK SIMILAR TO WHAT THE ECMWF HAD BEEN
ADVERTISING...WHICH WOULD FOCUS THE GREATEST PCPN CHANCES OVER THE
SRN PORTIONS OF THE CWA. FOR THE TODAY AND TONIGHT...HAVE LARGELY
FOLLOWED THE LOCAL WRFARW GUIDANCE WHICH IS WELL INITIALIZED AND
FOLLOWS THE MORE SOUTHERLY AND SLOW MOVING TRACK OF THE MAIN
SHORTWAVE. EARLY THIS MORNING...SHOWERS AND THUNDERSTORMS HAVE BEEN
MOVING THROUGH IA AND MO...AND ARE CROSSING THE MISSISSIPPI RIVER
INTO WEST CENTRAL IL. THE PCPN IS LARGELY FOCUSED ON THE NOSE OF A
STRONG LOW LEVEL JET. THIS SHOULD GRADUALLY PROGRESS EWD...AND
ANTICIPATE THAT THE MAIN AREA OF PCPN OVER THE CWA SHOULD GENERALLY
REMAIN SOUTH OF THE I-80 CORRIDOR. HOWEVER...THERE IS STILL A
SLIGHT CHANCE THAT SOME SCT SHRA OR AN ISOLATED THUNDERSTORM COULD
SNEAK INTO NERN IL...INCLUDING THE CHICAGO METRO AREA LATE THIS
AFTERNOON. HOWEVER...THE CHANCES SHOULD BE LOW AND COVERAGE SHOULD
BE SPARSE. FOR THE SOUTHERN PORTIONS OF THE CWA WHERE THE BULK OF
THE PCPN AFFECTING THE AREA SHOULD FALL...HIGH PWAT AIR AND SLOW
PROGRESSION UNDER GENERALLY LIGHT WINDS ALOFT COULD LEAD TO SOME
LOCALLY HEAVY RAINFALL WITH SOME OF THE STRONGER STORM CELLS.
WINDS TODAY SHOULD BE PREVAILING SWLY AS THE AS THE HIGH SLIDES TO
THE SOUTHEAST AND THE SFC LOW SLOWLY TRACKS ESEWD. WITH A WEAK
GRADIENT...WINDS SHOULD GENERALLY BE LESS THAN 10 MPH TODAY...BUT
THE STRONGER SWLY WINDS ALOFT ASSOCIATED WITH THE LOW LEVEL JET
AHEAD OF THE SFC LOW SHOULD PREVENT LAKE BREEZE DEVELOPMENT IN THE
ABSENCE OF A LAKE BREEZE...WARMER AIR SHOULD BE ABLE TO SPREAD UP TO
THE LAKEFRONT WITH TEMPS ARND 80F ACROSS THE AREA.
THE SECOND AREA OF CONCERN WILL BE THE COLD FRONT TRACKING DOWN LAKE
MICHIGAN AND THROUGH WISCONSIN. EXPECT THAT THE PORTION OF THE
FRONT OVER THE LAKE WILL SURGE FASTER THAN THE PORTION OVERLAND AND
EXPECT THAT THE FRONT SHOULD PUSH INTO SOUTHERN LAKE MICHIGAN AND
NERN IL DURG THE LATE EVENING HOURS. AS THE FRONT MOVES INTO NERN
IL...THE ZONE OF CONVERGENCE ASSOCIATED WITH THE FRONT WILL BE
DISRUPTED BY THE CYCLONIC FLOW AROUND THE SFC LOW...WHICH SHOULD
MOVE INTO WCNTRL IL LATE TONIGHT. SO...WITH THE CONVERGENCE ALONG
THE FRONT DIMINISHING OVERNIGHT AS THE FRONT PUSHES SOUTH...THE
CHANCES FOR PCPN ALONG THE BOUNDARY SHOULD ALSO DECREASE.
SO...WILL STILL CARRY SLIGHT CHANCE POPS AS THE BOUNDARY PUSHES
INTO NERN IL. THE MAIN IMPACT OF THE FRONT SHOULD BE TO DRAW LAKE
COOLED AIR INLAND WITH INCREASING LOW STRATUS AND POSSIBLE SOME
FOG DEVELOPMENT.
KREIN
SUNDAY THROUGH MONDAY...
OPERATIONAL SOLUTIONS HAVE CONTINUED TO POINT TOWARDS A SLIGHTLY
STRONGER SFC RIDGE OVER CENTRAL ONTARIO SLIDING SOUTH AND PUSHING A
QUASI-STATIONARY BOUNDARY FURTHER SOUTH SUN INTO CENTRAL IL. IF THIS
SOLUTION VERIFIES MUCH OF THE FORECAST AREA SUN WILL BE UNDER A COOL
AND RELATIVELY DRIER NORTHEAST FLOW. HAVE HELD ONTO LOW CHC POPS FOR
AREAS SOUTH OF I-80...BUT HAVE INCREASED CONFIDENCE THAT THIS TOO
WILL END UP BEING TRIMMED. THERE REMAINS SOME MID-LVL
MOISTURE...WITH MUCH OF THE GUIDANCE MEMBERS POINTING TOWARDS SOME
MID/UPR LVL CLOUDS. THAT BEING SAID HIGHS WILL LIKELY STRUGGLE TO
WARM MUCH BEYOND THE LOW/MID 70S. THE EXCEPTION WILL BE THE FAR
SOUTH/SOUTHWEST WHERE TEMPS COULD STILL PUSH INTO THE UPR 70S.
WEAK MID-LVL WAVE THAT WAS THOUGHT TO BRING PRECIP BACK INTO THE
FORECAST AREA SUN NGT/MON IS ALSO TRENDING FURTHER SOUTH IN THIS
TIME FRAME. GUIDANCE DOES TRY TO SLIDE THIS WEAK WAVE EAST THRU
SOUTHERN IL/IN...WITH SOME MID-LVL DIFFLUENCE ARRIVING OVER THE CWFA
SUN EVE. EXPECT MUCH OF SUN NGT TO END UP BEING DRY FOR NORTHERN
IL/NORTHWEST IN.
WITH A WEAK WAVE PUSHING EAST INTO SOUTHEAST IN ALONG WITH A WEAK
UPR LVL VORT SLIDING EAST ACROSS THE CENTRAL/NORTHERN PLAINS MON...A
GOOD PORTION OF MON COULD END UP BEING DRY WITH SOME CLOUDS. BY MON
EVE BETTER VORTICITY IN THE MID-LVLS ARRIVES WITH SOME INCREASED
MOISTURE BEING PROGGED IN THE LLVLS BY GUIDANCE. SO HAVE HELD ONTO
CHC POPS MON NGT FOCUSED IN THE WESTERN CWFA...MEANWHILE EXPECT THE
EASTERN HALF OF THE FORECAST AREA TO REMAIN DRY MON NGT. THE
CONTINUED NORTHEAST FLOW WILL KEEP TEMPS ONCE AGAIN SUB-SEASONAL FOR
MON...WITH HIGHS GENERALLY IN THE 70S. WINDS WILL BE SLOWLY TURNING
EAST/SOUTHEAST MON NGT WITH INCREASING LLVL MOISTURE...AND WILL
LIKELY HOLD TEMPS UP IN THE LOW 60S.
TUESDAY THROUGH FRIDAY...
THROUGHOUT THE EXTENDED PERIODS...ENSEMBLES HAVE THE NORTH ATLANTIC
RIDGE TRYING TO WEAKEN THEN RETROGRADING WEST/SOUTHWEST ACROSS
EASTERN CANADA. MEANWHILE THE WEAK TROUGHING ACROSS THE GREAT LAKES
WILL DISSOLVE AS PAC-NW RIDGING DEVELOPS AND CENTRAL ROCKIES TROUGHS
FORMS. THERE IS STILL CONSIDERABLE SPREAD AMONGST MEMBERS IN THE
EXTENDED...HOWEVER THERE IS A GENERAL THEME OF THE AFOREMENTIONED
OUTCOME.
OPERATIONAL SOLUTIONS FROM TUE THRU FRI PROG SOME FLATTENING IN THE
FLOW...OR A TRANSITION INTO A SEMI-ZONAL SETUP. THIS WOULD POINT
TOWARDS A RELATIVELY ACTIVE OR AT LEAST PERIODIC WAVES TRAVERSING
THE NORTHERN CONUS WITH OCCASIONAL CHANCES FOR
SHOWERS/THUNDERSTORMS. THEN CLOSER TO THE LATER PERIODS OF THE
CURRENT EXTENDED...THERE DOES APPEAR TO BE SOME LEANING IN GUIDANCE
THAT RIDGING WILL DEVELOP WITH A STEADY WARMING TREND. LLVL MOISTURE
IS ALSO PROGGED TO INCREASE LATE WEEK...WITH HIGHS NEARING THE
MID/UPR 80S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WINDS 8-12 KT THROUGH EARLY AFTERNOON THEN EXPECTED TO DECREASE
SLIGHTLY INTO LATE AFTERNOON.
* LOW CHANCE FOR A SHOWER OR SPRINKLE THIS AFTERNOON/EVENING.
* MVFR EXPECTED OVERNIGHT/SUNDAY MORNING WITH IFR POSSIBLE TOWARD
DAYBREAK. SCATTERING/LIFTING INTO SUNDAY AFTERNOON.
* NORTHEAST WINDS AROUND 10 KT SUNDAY.
MDB
//DISCUSSION...UPDATED 18Z...
AN UPPER LEVEL LOW CONTINUES TO SLOWLY SPIN EAST-SOUTHEAST ACROSS
SOUTHEAST IOWA. THIS IS DRIVING SOME SHOWER ACTIVITY ACROSS
CENTRAL ILLINOIS WITH JUST A FEW LIGHT RADAR RETURNS MOVING INTO
NORTHERN IL AND NORTHWEST IN. EXPECT THE BULK OF THE MORE
WIDESPREAD PRECIP TO OCCUR DOWN TOWARDS A PNT-RZL LINE WITH
SCATTERED COVERAGE UP TOWARDS JOT-VPZ AND ISOLATED POTENTIAL TO
THE NORTH. GYY MAY HAVE THE BEST CHANCE FOR A SHOWER. CANNOT RULE
OUT SOME ISOLATED TS. ABUNDANT CLOUD COVER CONTINUES ACROSS THE
AREA IN SEVERAL LAYERS WITH MAINLY VFR ACROSS THE AREA BUT WITH
MVFR MORE ABUNDANT BACK INTO SOUTHEAST IOWA AND WEST CENTRAL IL.
WINDS REMAIN QUITE VARIABLE WITH A WEAK RIDGE AXIS ANALYZED FROM
EAST CENTRAL TO NORTHWEST IL. A SOUTHWEST DIRECTION PREVAILS WITH
HIGHEST SPEEDS AT ORD/MDW WHERE HIGHER CLOUD COVERAGE HAS BEEN
MORE INTERMITTENT. THIS HAS ALLOWED MIXING TO DEEPEN AND LED TO
10-12 KT WIND SPEEDS AT TIMES. WINDS JUST OFF THE SURFACE SHOULD
START TO EASE UP THROUGH THE AFTERNOON SO THERE SHOULD BE A SLIGHT
DOWN TICK IN THE RANGE OF WIND SPEEDS. THE CAVEAT WOULD BE IF
THERE IS A DECREASE IN CLOUD COVER WHICH MAY KEEP WINDS CLOSER TO
WHERE THEY HAVE BEEN THROUGH MIDDAY.
A COOL FRONTAL BOUNDARY MOVES SOUTHWARD ACROSS THE AREA TONIGHT.
THIS IS EXPECTED TO BRING A PERIOD OF MVFR CIGS WITH IT AND MVFR
IS BEING REPORTED UPSTREAM. WITH COOL ADVECTION AND FLOW OFF THE
LAKE SOME IFR IS POSSIBLE TOWARD DAYBREAK BUT WILL KEEP THE IFR
LEVEL CLOUDS SCATTERED SUNDAY MORNING FOR NOW. SOME VSBY REDUCTION
IS POSSBLE BUT AM LESS CONFIDENT IN THIS. LOW CLOUD COVERAGE IS
EXPECTED TO LIFT THROUGH THE LATE MORNING/EARLY AFTERNOON AND MVFR
MAY BE IN PLACE AT SOME POINT DURING THE AFTERNOON. WINDS WILL
TURN NORTHEASTERLY BEHIND THE FRONT TONIGHT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM-HIGH CONFIDENCE IN WIND SPEEDS THROUGH EARLY
AFTERNOON...MEDIUM CONFIDENCE IN A SLIGHT DOWNWARD TREND INTO
LATE AFTERNOON.
* HIGH CONFIDENCE THAT PRECIP CHANCE IS LOW.
* MEDIUM-HIGH CONFIDENCE IN PERIOD OF MVFR CIGS TONIGHT/SUNDAY
MORNING. LOW CONFIDENCE IN IFR OCCURRING. LOW-MEDIUM CONFIDENCE
IN VSBY REDUCTION. MEDIUM CONFIDENCE IN TIMING OF IMPROVEMENT
SUNDAY.
* HIGH CONFIDENCE IN WINDS FOR SUNDAY.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH MONDAY...VFR. WX NIL.
MONDAY NIGHT THROUGH FRIDAY...PERIODIC CHANCES FOR SHRA/TSRA.
&&
.MARINE...
400 AM CDT
AS HIGH PRESSURE SLIDES OFF THE MID ATLANTIC COAST TODAY...LOW
PRESSURE WILL MOVE SLOWLY THROUGH THE MIDDLE MISSISSIPPI VALLEY
WHILE ANOTHER LOW OVER ONTARIO DRAGS A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN. A STRENGTHENING SWLY GRADIENT AHEAD OF THE COLD
FRONT WILL BRING INCREASING WINDS TO THE LAKE THROUGH THE MORNING
HOURS...APPROACHING 30 KT OVER THE NRN PORTIONS OF THE LAKE WHERE
THE GRADIENT WILL BE STRONGEST...WHILE WINDS OVER THE SRN
PORTIONS OF THE LAKE WILL STILL BE RATHER BRISK AT 15-25KT. THE
COLD FRONT WILL BEGIN TO PUSH OVER THE FAR NRN END OF THE LAKE
SHORTLY AFTER DAYBREAK AND STEADILY MOVE DOWN THE LAKE THROUGH THE
DAY TODAY. WINDS WILL QUICKLY TURN TO NLY FOLLOWING THE FROPA AND
WITH THE INITIAL SURGE OF COOLER AIR...WINDS SHOULD RAMP BACK UP
TO 30KT IMMEDIATELY FOLLOWING THE FROPA. HOWEVER...AS ANOTHER AREA
OF HIGH PRESSURE QUICKLY DROPS INTO THE THE UPPER GREAT LAKES
SATURDAY NIGHT...WINDS WILL DROP OFF WHILE VEERING TO MORE NELY.
AS THE HIGH CONTINUES TO BUILD TO THE EAST...WINDS WILL CONTINUE
TO VEER TO ELY AND THEN SELY SUNDAY NIGHT AND MONDAY. SELY WINDS
WILL THEN PERSIST ACROSS THE LAKE UNTIL MID WEEK AS ANOTHER LOW
PRESSURE SYSTEM DROPS OUT OF THE NRN PLAINS AND APPROACHES THE WRN
GREAT LAKE REGION BY LATE TUESDAY OR WEDNESDAY.
KREIN
&&
.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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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1232 PM CDT Sat Aug 16 2014
.UPDATE...
ISSUED AT 946 AM CDT SAT AUG 16 2014
Incoming area of showers and scattered storms has been showing
some fading over the last couple hours as it crosses the Illinois
River. Latest HRRR shows a narrower band of showers pushing past
the I-55 corridor midday, with some additional development
occurring to our west this afternoon near a low in southeast Iowa.
East central and southeast Illinois will see more in the way of
scattered showers through the day. Have sent some grid updates
earlier to reflect the current trends. Temperatures currently on
track and should mainly be confined to the 70s today with the
widespread cloud cover.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 323 AM CDT SAT AUG 16 2014
MCS over southern Iowa into northern Missouri early this morning
tracking slowly to the east and this feature will be our main
concern through tonight. Well out ahead of the MCS to our west, we
have had some isolated showers develop over parts of central and
east central Illinois during the past several hours. Unlike last
night at this time when we were seeing dew points in the upper 40s
to lower 50s over our northeast counties, most areas have seen the
dew points climb back well into the 60s.
Most of the short term models move the MCV associated with the
current convection out in northern Missouri/southern Iowa slowly
into southeast Iowa by late this afternoon. Current band of showers
and isolated storms will shift slowly east of the Mississippi River
by dawn this morning and continue to edge slowly east during the
morning with a gradual decrease in areal coverage as the main
support from the low level jet wanes with time early this morning.
The extensive cloud cover and showers will keep temps below guid in
most areas except the far east where the rain will not get into that
part of our forecast area until later today.
Most of the hi-resolution model solutions redevelop the convection
to the east of the MCV later this afternoon into parts of west
central Illinois and then shift the precip to the east tonight as
the vort center tracks into central IL by Sunday morning.
Precipitable water values still forecast well above 2 inches tonight
with warm cloud depths above 3km indicating some very efficient
rains with any convection that develops just to the east of the vort
center tonight. Upper winds are also forecast to weaken considerably
indicating the storms that do develop near or to the east/southeast
of the MCV will be slow movers and threaten parts of our area with
heavy rainfall. However, one negative factor for widespread heavy
rainfall will be with a much weaker low level jet than what we are
seeing out to our west tonight. Still, with the high PWAT values in
place, any storms that develop late this afternoon thru this evening
will be capable of producing high rainfall rates along and to the
east of the MCV overnight.
&&
.LONG TERM...(Sunday through Friday)
ISSUED AT 323 AM CDT SAT AUG 16 2014
Upper disturbance remaining over the FA Sunday morning in the
models. Models not really responding to the MCV equally as the low
moves out to the east. A lot of uncertainty as the day progresses,
but the better chances for the continuation of precip remain in the
east and southeast as the system tracks out to the east, just north
of the Ohio River Valley. Models dry out briefly for early Monday
morning, and chances through the day on Monday starting to drop off
a bit. Less amplified flow over the country looking messy through
the work week. Heat that has been building over the desert
southwest makes its way into the region warming up the temps to far
more of a summer pattern that has been to this point. Temps in the
upper 80s/lower 90s Wed-Friday. Weak flow aloft and a series of
small waves dipping into the Great Lakes/Midwest keeping ILX in an
unsettled weather pattern and pops dominate the extended forecast
with periodic chances for precip. Models diverge significantly
going into the weekend with the GFS building in a ridge for the
Midwest and southern Plains, while the ECMWF remains more
progressive with pushing a trof across the nrn tier of the CONUS.
Should the forecast go more the way of the GFS with subsequent
issues, the temperatures may need to be bumped up a couple degrees
under a persistent ridge. But with the ECMWF in direct opposition
and the timing of waves such a question mark...not willing to
deviate too much from what the AllBlend has in the grids just yet.
All in all, a warm forecast with periodic showers. PW values
trending down from where they were 24 hrs ago, but chances for some
of the thunderstorms to produce some heavy rain. Upper dynamics not
particularly alarming any one day just yet...but this pattern is
more reminiscent of summer than what has been around so far.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1232 PM CDT SAT AUG 16 2014
Widespread MVFR ceilings across most of central Illinois at
midday. This should linger for a few hours, before lifting a bit
late afternoon. So far the showers have only been scattered at the
TAF sites and the main wave has been eroding, with KSPI the main
threat from it. However, thunder has been diminishing and have
removed the VCTS mentions from the TAFs until this evening. Made
little change to the forecasts beyond 06Z, with MVFR to
potentially IFR conditions developing and continuing into Sunday
morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1112 AM CDT SAT AUG 16 2014
.DISCUSSION...
339 AM CDT
SHORT TERM...THROUGH SATURDAY NIGHT...
FOR THE REMAINDER OF THE NIGHT AND INTO SATURDAY MORNING...HIGH
PRESSURE CONTINUES TO SLIDE SOUTHEAST INTO THE CENTRAL APPALACHIANS
WITH A RIDGE AXIS EXTENDING NORTHWEST INTO SOUTHERN MINNESOTA. LOW
PRESSURE MOVING THROUGH ONTARIO IS DRAGGING A COLD FRONT INTO THE
UPPER GREAT LAKES REGION. WITH CLEAR SKIES AND LIGHT WINDS UNDER
THE RIDGE AXIS...SOME PATCHY FOG IS FORMING OVER NWRN AND NCNTRL IL
WHERE TEMPERATURES HAVE BEEN ABLE TO RADIATE LOWER AND A RETURN FLOW
OF MOISTURE AROUND THE WESTERN PERIPHERY OF THE HIGH HAS RAISED
DEWPOINTS INTO UPPER 50S. THE PATCHY FOG MAY INCREASE IN COVERAGE
THROUGH THE REMAINDER OF THE LATE NIGHT HOURS...BUT DO NOT
ANTICIPATE WIDESPREAD DENSE FOG.
INTO THE MORNING HOURS...THE INITIAL CONCERN WILL BE THE SPREAD OF
SHRA/TSRA INTO WEST CENTRAL IL ASSOCIATED WITH A VERY SLOW MOVING
SHORTWAVE OVER SCNTRL IA/NCNTRL MO. THE TREND OF THIS SYSTEM HAS
BEEN ON A MORE SOUTHERLY TRACK SIMILAR TO WHAT THE ECMWF HAD BEEN
ADVERTISING...WHICH WOULD FOCUS THE GREATEST PCPN CHANCES OVER THE
SRN PORTIONS OF THE CWA. FOR THE TODAY AND TONIGHT...HAVE LARGELY
FOLLOWED THE LOCAL WRFARW GUIDANCE WHICH IS WELL INITIALIZED AND
FOLLOWS THE MORE SOUTHERLY AND SLOW MOVING TRACK OF THE MAIN
SHORTWAVE. EARLY THIS MORNING...SHOWERS AND THUNDERSTORMS HAVE BEEN
MOVING THROUGH IA AND MO...AND ARE CROSSING THE MISSISSIPPI RIVER
INTO WEST CENTRAL IL. THE PCPN IS LARGELY FOCUSED ON THE NOSE OF A
STRONG LOW LEVEL JET. THIS SHOULD GRADUALLY PROGRESS EWD...AND
ANTICIPATE THAT THE MAIN AREA OF PCPN OVER THE CWA SHOULD GENERALLY
REMAIN SOUTH OF THE I-80 CORRIDOR. HOWEVER...THERE IS STILL A
SLIGHT CHANCE THAT SOME SCT SHRA OR AN ISOLATED THUNDERSTORM COULD
SNEAK INTO NERN IL...INCLUDING THE CHICAGO METRO AREA LATE THIS
AFTERNOON. HOWEVER...THE CHANCES SHOULD BE LOW AND COVERAGE SHOULD
BE SPARSE. FOR THE SOUTHERN PORTIONS OF THE CWA WHERE THE BULK OF
THE PCPN AFFECTING THE AREA SHOULD FALL...HIGH PWAT AIR AND SLOW
PROGRESSION UNDER GENERALLY LIGHT WINDS ALOFT COULD LEAD TO SOME
LOCALLY HEAVY RAINFALL WITH SOME OF THE STRONGER STORM CELLS.
WINDS TODAY SHOULD BE PREVAILING SWLY AS THE AS THE HIGH SLIDES TO
THE SOUTHEAST AND THE SFC LOW SLOWLY TRACKS ESEWD. WITH A WEAK
GRADIENT...WINDS SHOULD GENERALLY BE LESS THAN 10 MPH TODAY...BUT
THE STRONGER SWLY WINDS ALOFT ASSOCIATED WITH THE LOW LEVEL JET
AHEAD OF THE SFC LOW SHOULD PREVENT LAKE BREEZE DEVELOPMENT IN THE
ABSENCE OF A LAKE BREEZE...WARMER AIR SHOULD BE ABLE TO SPREAD UP TO
THE LAKEFRONT WITH TEMPS ARND 80F ACROSS THE AREA.
THE SECOND AREA OF CONCERN WILL BE THE COLD FRONT TRACKING DOWN LAKE
MICHIGAN AND THROUGH WISCONSIN. EXPECT THAT THE PORTION OF THE
FRONT OVER THE LAKE WILL SURGE FASTER THAN THE PORTION OVERLAND AND
EXPECT THAT THE FRONT SHOULD PUSH INTO SOUTHERN LAKE MICHIGAN AND
NERN IL DURG THE LATE EVENING HOURS. AS THE FRONT MOVES INTO NERN
IL...THE ZONE OF CONVERGENCE ASSOCIATED WITH THE FRONT WILL BE
DISRUPTED BY THE CYCLONIC FLOW AROUND THE SFC LOW...WHICH SHOULD
MOVE INTO WCNTRL IL LATE TONIGHT. SO...WITH THE CONVERGENCE ALONG
THE FRONT DIMINISHING OVERNIGHT AS THE FRONT PUSHES SOUTH...THE
CHANCES FOR PCPN ALONG THE BOUNDARY SHOULD ALSO DECREASE.
SO...WILL STILL CARRY SLIGHT CHANCE POPS AS THE BOUNDARY PUSHES
INTO NERN IL. THE MAIN IMPACT OF THE FRONT SHOULD BE TO DRAW LAKE
COOLED AIR INLAND WITH INCREASING LOW STRATUS AND POSSIBLE SOME
FOG DEVELOPMENT.
KREIN
SUNDAY THROUGH MONDAY...
OPERATIONAL SOLUTIONS HAVE CONTINUED TO POINT TOWARDS A SLIGHTLY
STRONGER SFC RIDGE OVER CENTRAL ONTARIO SLIDING SOUTH AND PUSHING A
QUASI-STATIONARY BOUNDARY FURTHER SOUTH SUN INTO CENTRAL IL. IF THIS
SOLUTION VERIFIES MUCH OF THE FORECAST AREA SUN WILL BE UNDER A COOL
AND RELATIVELY DRIER NORTHEAST FLOW. HAVE HELD ONTO LOW CHC POPS FOR
AREAS SOUTH OF I-80...BUT HAVE INCREASED CONFIDENCE THAT THIS TOO
WILL END UP BEING TRIMMED. THERE REMAINS SOME MID-LVL
MOISTURE...WITH MUCH OF THE GUIDANCE MEMBERS POINTING TOWARDS SOME
MID/UPR LVL CLOUDS. THAT BEING SAID HIGHS WILL LIKELY STRUGGLE TO
WARM MUCH BEYOND THE LOW/MID 70S. THE EXCEPTION WILL BE THE FAR
SOUTH/SOUTHWEST WHERE TEMPS COULD STILL PUSH INTO THE UPR 70S.
WEAK MID-LVL WAVE THAT WAS THOUGHT TO BRING PRECIP BACK INTO THE
FORECAST AREA SUN NGT/MON IS ALSO TRENDING FURTHER SOUTH IN THIS
TIME FRAME. GUIDANCE DOES TRY TO SLIDE THIS WEAK WAVE EAST THRU
SOUTHERN IL/IN...WITH SOME MID-LVL DIFFLUENCE ARRIVING OVER THE CWFA
SUN EVE. EXPECT MUCH OF SUN NGT TO END UP BEING DRY FOR NORTHERN
IL/NORTHWEST IN.
WITH A WEAK WAVE PUSHING EAST INTO SOUTHEAST IN ALONG WITH A WEAK
UPR LVL VORT SLIDING EAST ACROSS THE CENTRAL/NORTHERN PLAINS MON...A
GOOD PORTION OF MON COULD END UP BEING DRY WITH SOME CLOUDS. BY MON
EVE BETTER VORTICITY IN THE MID-LVLS ARRIVES WITH SOME INCREASED
MOISTURE BEING PROGGED IN THE LLVLS BY GUIDANCE. SO HAVE HELD ONTO
CHC POPS MON NGT FOCUSED IN THE WESTERN CWFA...MEANWHILE EXPECT THE
EASTERN HALF OF THE FORECAST AREA TO REMAIN DRY MON NGT. THE
CONTINUED NORTHEAST FLOW WILL KEEP TEMPS ONCE AGAIN SUB-SEASONAL FOR
MON...WITH HIGHS GENERALLY IN THE 70S. WINDS WILL BE SLOWLY TURNING
EAST/SOUTHEAST MON NGT WITH INCREASING LLVL MOISTURE...AND WILL
LIKELY HOLD TEMPS UP IN THE LOW 60S.
TUESDAY THROUGH FRIDAY...
THROUGHOUT THE EXTENDED PERIODS...ENSEMBLES HAVE THE NORTH ATLANTIC
RIDGE TRYING TO WEAKEN THEN RETROGRADING WEST/SOUTHWEST ACROSS
EASTERN CANADA. MEANWHILE THE WEAK TROUGHING ACROSS THE GREAT LAKES
WILL DISSOLVE AS PAC-NW RIDGING DEVELOPS AND CENTRAL ROCKIES TROUGHS
FORMS. THERE IS STILL CONSIDERABLE SPREAD AMONGST MEMBERS IN THE
EXTENDED...HOWEVER THERE IS A GENERAL THEME OF THE AFOREMENTIONED
OUTCOME.
OPERATIONAL SOLUTIONS FROM TUE THRU FRI PROG SOME FLATTENING IN THE
FLOW...OR A TRANSITION INTO A SEMI-ZONAL SETUP. THIS WOULD POINT
TOWARDS A RELATIVELY ACTIVE OR AT LEAST PERIODIC WAVES TRAVERSING
THE NORTHERN CONUS WITH OCCASIONAL CHANCES FOR
SHOWERS/THUNDERSTORMS. THEN CLOSER TO THE LATER PERIODS OF THE
CURRENT EXTENDED...THERE DOES APPEAR TO BE SOME LEANING IN GUIDANCE
THAT RIDGING WILL DEVELOP WITH A STEADY WARMING TREND. LLVL MOISTURE
IS ALSO PROGGED TO INCREASE LATE WEEK...WITH HIGHS NEARING THE
MID/UPR 80S.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* SOUTHWEST WINDS VARIABLE BETWEEN 9 AND 12 KT THROUGH MID
AFTERNOON.
* LOW CHANCE FOR SHRA AND MINIMAL CHANCE FOR TSRA THIS AFTERNOON.
MDB
//DISCUSSION...UPDATED 16Z...
WIND SPEEDS CONTINUE TO VARY QUITE A BIT ACROSS THE TERMINALS WITH
ORD/MDW SEEING THE OVERALL HIGHEST SPEEDS. RANGE OF SPEEDS HAS
INCREASED FROM 7-10 KT INTO THE 9-12 KT RANGE AND EXPECT THIS TO
CONTINUE THROUGH EARLY AFTERNOON. WITH VARIABLE COVERAGE OF CLOUDS
CURRENTLY AT LOWER LEVELS...VARIABILITY IN SPEEDS IS SOMEWHAT HIGH
AS MIXING TRIES TO BECOME BETTER ESTABLISHED. OVERALL EXPECT SPEEDS
TO VARY A FEW KNOTS EITHER SIDE OF 10 KT. SPEEDS MAY START TO EASE
SLIGHTLY MID TO LATE AFTERNOON AS FORECAST SOUNDINGS SUGGEST WINDS
JUST ABOVE THE SURFACE EASING SLIGHTLY AND CLOUD COVER REMAINING
ABUNDANT.
MDB
FROM 12Z...
HIGH PRESSURE CONTINUES TO SETTLE SOUTHEAST INTO THE CNTRL
APPALACHIANS AS LOW PRESSURE TRACKS THROUGH SRN ONTARIO AND
ANOTHER LOW MOVES INTO SWRN IOWA. A COLD FRONT ASSOCIATED WITH
THE CANADIAN LOW WILL BEGIN TO PUSH SOUTH DOWN THE LENGTH OF LAKE
MICHIGAN WHILE THE OTHER SFC LOW MOVES ALONG THE IA/MO BORDER.
SHOWERS AND THUNDERSTORMS AT THE NOSE OF A LOW LEVEL JET...AT
12Z...WERE MOVING INTO WEST-CENTRAL IL. THE LATEST HIGH RES MODEL
GUIDANCE INDICATES THAT THIS LOW SHOULD TREND ON AN EVEN MORE
SOUTHERLY TRACK THAN PREVIOUSLY ANTICIPATED...INTO NERN MO BY
EARLY EVENING. WARM MOIST ADVECTION IN THE SWLY SLOW AHEAD OF THE
LOW WILL CONTINUE TO DRAW MOISTURE NEWD THROUGH IL..SETTING UP
WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS INTO CENTRAL IL
THROUGH THE MORNING HOURS SATURDAY...WITH SOME SHOWERS POSSIBLE
REACHING THE I-80 CORRIDOR BY ARND 18Z. WITH A MORE SOUTHERLY
TRACK TO THE SYSTEM...CHANCES FOR SHRA/TSRA MAY BE EVEN LOWER THAN
WHAT WOULD BE ASSOCIATED WITH THE VCSH GROUP...BUT WILL MAINTAIN
THIS IN THE FORECAST AS THERE IS STILL SOME CHANCE FOR SOME ISOLD
SHRA OR AN EVEN MORE ISOLD TS SNEAKING INTO THE VICINITY OF THE
CHICAGO AREA TERMINALS. ONE CHANGE TO THE GOING FORECAST WILL BE
TO INCREASE THE SUSTAINED SLWY WIND SPEEDS THIS AFTERNOON TO
10-12KT AS A BIT LESS CLOUD COVER COULD ALL FOR SOME BETTER MIXING
TO TAP THE STRONGER WINDS ALOFT. AN OCNL GUST TO 15KT IS POSSIBLE.
THE NEXT CONCERN WILL BE ASSOCIATED WITH THE COLD FRONT PUSHING
SWD THROUGH WI AND DOWN LAKE MICHIGAN. THE LATEST GUIDANCE
MAINTAINS THE IDEA THAT THE FRONT WILL NOT REACH THE CHICAGO AREA
TERMINALS UNTIL AROUND MIDNIGHT...OR SLIGHTLY LATER...AND A
LITTLE LATER FOR RFD DUE TO THE FASTER SURGE OF THE FRONT OVER THE
LAKE. WINDS SHOULD TURN NELY FOLLOWING THE FROPA AND INCREASE TO
10-15KT. NELY FLOW WILL ALSO DRAW LAKE COOLED AIR INTO NERN
IL/NWRN IN...AND CIGS/VIS SHOULD LOWER INTO LOWER END MVFR LEVELS
LATE TONIGHT OR DURG THE EARLY MORNING HOURS. THERE IS ALSO A
CHANCE CIGS COULD LOWER TO IFR LEVELS WITH A FEW SHOWERS...SO HAVE
ADDED A PROB30 GROUP TO ACCOUNT FOR THIS POTENTIAL.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN 9-12 KT WINDS THROUGH EARLY/MID AFTERNOON.
MEDIUM CONFIDENCE THAT RANGES OF SPEEDS WILL LOWER SLIGHTLY INTO
LATE AFTERNOON.
* MEDIUM-HIGH CONFIDENCE THAT SHRA CHANCES ARE LOW THIS AFTERNOON
AND THAT TSRA CHANCE IS MINIMAL.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT THROUGH MONDAY...VFR. WX NIL.
MONDAY NIGHT THROUGH FRIDAY...PERIODIC CHANCES FOR SHRA/TSRA.
&&
.MARINE...
400 AM CDT
AS HIGH PRESSURE SLIDES OFF THE MID ATLANTIC COAST TODAY...LOW
PRESSURE WILL MOVE SLOWLY THROUGH THE MIDDLE MISSISSIPPI VALLEY
WHILE ANOTHER LOW OVER ONTARIO DRAGS A COLD FRONT DOWN THE LENGTH
OF LAKE MICHIGAN. A STRENGTHENING SWLY GRADIENT AHEAD OF THE COLD
FRONT WILL BRING INCREASING WINDS TO THE LAKE THROUGH THE MORNING
HOURS...APPROACHING 30 KT OVER THE NRN PORTIONS OF THE LAKE WHERE
THE GRADIENT WILL BE STRONGEST...WHILE WINDS OVER THE SRN
PORTIONS OF THE LAKE WILL STILL BE RATHER BRISK AT 15-25KT. THE
COLD FRONT WILL BEGIN TO PUSH OVER THE FAR NRN END OF THE LAKE
SHORTLY AFTER DAYBREAK AND STEADILY MOVE DOWN THE LAKE THROUGH THE
DAY TODAY. WINDS WILL QUICKLY TURN TO NLY FOLLOWING THE FROPA AND
WITH THE INITIAL SURGE OF COOLER AIR...WINDS SHOULD RAMP BACK UP
TO 30KT IMMEDIATELY FOLLOWING THE FROPA. HOWEVER...AS ANOTHER AREA
OF HIGH PRESSURE QUICKLY DROPS INTO THE THE UPPER GREAT LAKES
SATURDAY NIGHT...WINDS WILL DROP OFF WHILE VEERING TO MORE NELY.
AS THE HIGH CONTINUES TO BUILD TO THE EAST...WINDS WILL CONTINUE
TO VEER TO ELY AND THEN SELY SUNDAY NIGHT AND MONDAY. SELY WINDS
WILL THEN PERSIST ACROSS THE LAKE UNTIL MID WEEK AS ANOTHER LOW
PRESSURE SYSTEM DROPS OUT OF THE NRN PLAINS AND APPROACHES THE WRN
GREAT LAKE REGION BY LATE TUESDAY OR WEDNESDAY.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
947 AM CDT Sat Aug 16 2014
.UPDATE...
ISSUED AT 946 AM CDT SAT AUG 16 2014
Incoming area of showers and scattered storms has been showing
some fading over the last couple hours as it crosses the Illinois
River. Latest HRRR shows a narrower band of showers pushing past
the I-55 corridor midday, with some additional development
occurring to our west this afternoon near a low in southeast Iowa.
East central and southeast Illinois will see more in the way of
scattered showers through the day. Have sent some grid updates
earlier to reflect the current trends. Temperatures currently on
track and should mainly be confined to the 70s today with the
widespread cloud cover.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 323 AM CDT SAT AUG 16 2014
MCS over southern Iowa into northern Missouri early this morning
tracking slowly to the east and this feature will be our main
concern through tonight. Well out ahead of the MCS to our west, we
have had some isolated showers develop over parts of central and
east central Illinois during the past several hours. Unlike last
night at this time when we were seeing dew points in the upper 40s
to lower 50s over our northeast counties, most areas have seen the
dew points climb back well into the 60s.
Most of the short term models move the MCV associated with the
current convection out in northern Missouri/southern Iowa slowly
into southeast Iowa by late this afternoon. Current band of showers
and isolated storms will shift slowly east of the Mississippi River
by dawn this morning and continue to edge slowly east during the
morning with a gradual decrease in areal coverage as the main
support from the low level jet wanes with time early this morning.
The extensive cloud cover and showers will keep temps below guid in
most areas except the far east where the rain will not get into that
part of our forecast area until later today.
Most of the hi-resolution model solutions redevelop the convection
to the east of the MCV later this afternoon into parts of west
central Illinois and then shift the precip to the east tonight as
the vort center tracks into central IL by Sunday morning.
Precipitable water values still forecast well above 2 inches tonight
with warm cloud depths above 3km indicating some very efficient
rains with any convection that develops just to the east of the vort
center tonight. Upper winds are also forecast to weaken considerably
indicating the storms that do develop near or to the east/southeast
of the MCV will be slow movers and threaten parts of our area with
heavy rainfall. However, one negative factor for widespread heavy
rainfall will be with a much weaker low level jet than what we are
seeing out to our west tonight. Still, with the high PWAT values in
place, any storms that develop late this afternoon thru this evening
will be capable of producing high rainfall rates along and to the
east of the MCV overnight.
&&
.LONG TERM...(Sunday through Friday)
ISSUED AT 323 AM CDT SAT AUG 16 2014
Upper disturbance remaining over the FA Sunday morning in the
models. Models not really responding to the MCV equally as the low
moves out to the east. A lot of uncertainty as the day progresses,
but the better chances for the continuation of precip remain in the
east and southeast as the system tracks out to the east, just north
of the Ohio River Valley. Models dry out briefly for early Monday
morning, and chances through the day on Monday starting to drop off
a bit. Less amplified flow over the country looking messy through
the work week. Heat that has been building over the desert
southwest makes its way into the region warming up the temps to far
more of a summer pattern that has been to this point. Temps in the
upper 80s/lower 90s Wed-Friday. Weak flow aloft and a series of
small waves dipping into the Great Lakes/Midwest keeping ILX in an
unsettled weather pattern and pops dominate the extended forecast
with periodic chances for precip. Models diverge significantly
going into the weekend with the GFS building in a ridge for the
Midwest and southern Plains, while the ECMWF remains more
progressive with pushing a trof across the nrn tier of the CONUS.
Should the forecast go more the way of the GFS with subsequent
issues, the temperatures may need to be bumped up a couple degrees
under a persistent ridge. But with the ECMWF in direct opposition
and the timing of waves such a question mark...not willing to
deviate too much from what the AllBlend has in the grids just yet.
All in all, a warm forecast with periodic showers. PW values
trending down from where they were 24 hrs ago, but chances for some
of the thunderstorms to produce some heavy rain. Upper dynamics not
particularly alarming any one day just yet...but this pattern is
more reminiscent of summer than what has been around so far.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 600 AM CDT SAT AUG 16 2014
As a large area of showers and isolated thunderstorms pushes into
western Illinois this morning, we expect a gradual deterioration
in cigs and vsbys from west to east today. Rain will continue to
edge slowly east and start to affect the SPI taf area first this
morning followed by PIA with the remainder of the TAF sites seeing
the rain late this morning into the afternoon. Already seeing some
isolated showers just east of CMI, but still think the bulk of the
rain to the west may take until this afternoon to get into CMI.
Once the rain begins, cigs will drop to MVFR and even the possibility
for some brief IFR cigs/vsbys in the heavier showers. Not seeing much
in the way of lightning activity so at this point will continue to
handle it with SHRA with VCTS. As the upper level circulation works
its way into our area tonight, it appears we will see widespread
MVFR and local IFR cigs and vsbys with rain and isolated TSRA with
areas of fog. Surface winds today will be south to southeast at 8
to 15 kts with winds backing more into the east tonight as the
surface low tracks just south of the TAF sites. Wind speeds tonight
will be from 4 to 9 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...SMITH
LONG TERM...HJS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1259 AM CDT SAT AUG 16 2014
.DISCUSSION...
254 PM CDT
THE MAIN FORECAST CONCERNS WILL CONTINUE TO FOCUS ON THE CHANCES OF
THUNDERSTORMS AND THE POSSIBILITY OF HEAVY RAIN ACROSS PORTIONS OF MY
AREA THROUGH THE WEEKEND.
COOL SURFACE HIGH PRESSURE CONTINUES TO SHIFT EAST-SOUTHEASTWARD
OVER THE OHIO VALLEY EARLY THIS AFTERNOON. THIS IS PRODUCING ANOTHER
FABULOUS WEATHER DAY ACROSS THE REGION THIS AFTERNOON WITH
TEMPERATURES PRIMARILY IN THE MID TO UPPER 70S. HOWEVER...ATTENTION
IS BEGINNING TO FOCUS ON THE SYSTEM TO OUR WEST...WHICH IS ALREADY
PUSHING SOME HIGHER LEVEL CLOUDINESS INTO MY SOUTHWESTERN AREAS.
WATER VAPOR IMAGERY EARLY THIS AFTERNOON INDICATES THE PRESENCE OF A
COUPLE OF MID/UPPER LEVEL DISTURBANCES ACROSS THE PLAINS. THE FIRST
IS LOCATED OVER THE WESTERN DAKOTAS...WITH THE SECOND OVER THE
NEBRASKA-KANSAS BOARDER. HOWEVER...IT IS THE SOUTHERNMOST
DISTURBANCE THAT IS THE MAIN FOCUS FOR THE WEATHER EXPECTED MUCH OF
THIS WEEKEND ACROSS NORTHERN ILLINOIS/NORTHWESTERN INDIANA. MODEL
GUIDANCE IS IN GOOD AGREEMENT WITH TRACKING THIS DISTURBANCE SLOWLY
EASTWARD ACROSS SOUTHERN IOWA TONIGHT...THEN EAST-SOUTHEASTWARD
ACROSS CENTRAL ILLINOIS BY SUNDAY MORNING. THE GFS AND ECMWF ARE
FAVORED WITH THE HANDLING OF THE SYSTEM THROUGH THE WEEKEND.
CONVECTIVE ACTIVITY WILL LIKELY FIRE UP DOWNSTREAM OF THE SOUTHERN
NEBRASKA DISTURBANCE TONIGHT...NAMELY ACROSS PORTIONS OF SOUTHERN
IOWA...MISSOURI AND PERHAPS ACROSS FAR WESTERN ILLINOIS ALONG THE
NOSE OF A DEVELOPING SOUTH-SOUTHWESTERLY LOW LEVEL JET. THE REMNANTS
OF SOME OF THIS ACTIVITY WILL TRY TO MOVE EASTWARD ACROSS THE AREA
SATURDAY MORNING. HOWEVER...IT APPEARS THIS ACTIVITY WILL LIKELY
WEAKEN CONSIDERABLY WITH EASTWARD EXTENT DURING THE MORNING AS IT
MOVES AWAY FROM THE BETTER FORCING AND INSTABILITY. AS SUCH...IT
APPEARS THE THREAT FOR THUNDERSTORMS WILL BE LOW ACROSS MUCH OF
NORTHEASTERN ILLINOIS AND INTO INDIANA...WITH POSSIBLY ONLY SOME
SHOWERS VOID OF THUNDER POSSIBLE.
ADDITIONAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE SATURDAY
AFTERNOON AND NIGHT AS THE MAIN UPPER SYSTEM MOVES FROM SOUTHEASTERN
IOWA OVER CENTRAL ILLINOIS. HOWEVER...AGAIN IT APPEARS THE MAIN
THREAT OF THUNDER WILL REMAIN ALONG AND SOUTH OF INTERSTATE 80 TO
THE EAST OF THE TRACK OF THE MID LEVEL WAVE. THERE IS A THREAT FOR
SOME VERY HEAVY RAINFALL WITH THESE STORMS ON SATURDAY/SATURDAY
NIGHT ACROSS CENTRAL ILLINOIS GIVEN PWATS COULD BE IN EXCESS OF 2
INCHES AND WARM CLOUD DEPTHS IN EXCESS OF 13,000 FEET. THIS THREAT
WILL NEED TO BE WATCHED...BUT AT THIS TIME IT APPEARS THE PRIMARILY
THREAT FOR THIS HEAVY RAINFALL COULD REMAIN JUST OUTSIDE MY AREA.
A COLD FRONT IS ALSO EXPECTED TO DROP DOWN LAKE MICHIGAN LATE
SATURDAY. THIS COLD FRONT SHOULD SHIFT SOUTHWARD ACROSS NORTHERN
ILLINOIS BY LATE SATURDAY NIGHT/EARLY SUNDAY MORNING. ONCE THIS
FRONT PUSHES THROUGH...ONSHORE FLOW WILL PREVAIL ACROSS NORTHEASTERN
ILLINOIS AND PORTIONS OF NORTHWESTERN INDIANA. THIS SHOULD KEEP MUCH
OF NORTHERN ILLINOIS DRY BUT CLOUDY ON SUNDAY. AS A RESULT...I
HAVE DROPPED POPS ACROSS MUCH OF NORTHERN ILLINOIS ON SUNDAY.
HOWEVER...THE EFFECTS OF THE MID LEVEL SYSTEM WILL STILL POSSIBLY
LEAD TO ADDITIONAL THUNDERSTORMS SUNDAY...PRIMARILY ACROSS MY EAST
CENTRAL ILLINOIS AND NORTHWESTERN INDIANA COUNTIES. HEAVY RAINFALL
WILL AGAIN BE A THREAT WITH THESE STORMS.
THINGS FINALLY QUITE DOWN AREA-WIDE FOR A SHORT PERIOD LATE MONDAY.
HOWEVER...THE WEATHER PATTERN FROM MID TO LATE THIS COMING WEEK
LOOKS TO BE A WARMER AND ACTIVE AT TIMES. THE UPPER LOW/TROUGH
CURRENT IN PLACE ACROSS THE PACIFIC NORTHWEST IS PROGGED TO SHIFT
EASTWARD ACROSS THE UPPER MIDWEST BY TUESDAY. THIS WILL BRING OUR
NEXT CHANCE OF SHOWERS AND STORMS TO AREA...ALONG WITH WARMER
TEMPERATURES. ADDITIONAL WAVES OF STORMS ARE POSSIBLE LATER IN THE
WEEK AS WELL WITH THE LIKELIHOOD OF THE MID/UPPER LEVEL PATTERN
REMAINING DISTURBED ACROSS THE NORTHERN HALF OF THE COUNTRY.
KJB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* SOUTHWEST WINDS UP TO 10 KT AT TIMES SATURDAY AFTERNOON.
* A CHANCE FOR SHOWERS AND A SMALLER CHANCE OF THUNDERSTORMS FROM
MID SATURDAY AFTERNOON THROUGH EARLY SATURDAY EVENING.
KREIN
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE CONTINUES TO SETTLE SOUTHEAST INTO THE CNTRL
APPALACHIANS AS LOW PRESSURE TRACKS THROUGH SRN ONTARIO AND
ANOTHER LOW MOVES INTO SWRN IOWA. WINDS HAVE DROPPED OFF TO LIGHT
AND VARIABLE OR LIGHT SWLY AS A RIDGE AXIS EXTENDS NORTHWEST FROM
THE SFC HIGH INTO SRN MN. THROUGH THE NIGHT AND TOMORROW
MORNING...A COLD FRONT ASSOCIATED WITH THE CANADIAN LOW WILL
BEGIN TO PUSH SOUTH DOWN THE LENGTH OF LAKE MICHIGAN WHILE THE
OTHER SFC LOW MOVES ALONG THE IA/MO BORDER. SHOWERS AND
THUNDERSTORMS AT THE NOSE OF A LOW LEVEL JET...AT 06Z...EXTEND
FROM NWRN MO/SWRN IA THROUGH ERN MO. THE LATEST HIGH RES MODEL
GUIDANCE INDICATES THAT THIS LOW WILL MOVE VERY SLOWLY ONLY TO THE
SERN CORNER OF IA OR THE NERN CORNER OF MO. WARM MOIST ADVECTION
IN THE SWLY SLOW AHEAD OF THE LOW WILL CONTINUE TO DRAW MOISTURE
NEWD THROUGH IL..SETTING UP WIDESPREAD SHOWERS AND EMBEDDED
THUNDERSTORMS INTO CENTRAL IL THROUGH THE MORNING HOURS
SATURDAY...WITH SOME SHOWERS POSSIBLE REACHING THE I-80 CORRIDOR
BY ARND 18Z. THE TREND OF THE UPPER LEVEL SYSTEM ASSOCIATED WITH
THIS SFC LOW IS TRENDING A LITTLE FARTHER SOUTH THAN PREVIOUS
GUIDANCE...SO THERE IS A DECREASING LIKELIHOOD OF WIDESPREAD PCPN
REACHING THE TERMINALS. WILL MAINTAIN THE VCSH GROUP FOR THE LATE
AFTERNOON AS THE HIGH RES GUIDANCE DOES INDICATE SOME PCPN
SNEAKING INTO NERN IL...INVOF THE CHICAGO AREA TERMINALS...BUT
WITH THE AREA SITTING BETWEEN THE SFC LOW AND A COLD FRONT PUSHING
SOUTH THROUGH WI AND LAKE MICHIGAN...THERE COULD BE ENOUGH SFC
DIVERGENCE THAT PCPN COULD BE MINIMIZED.
SFC WINDS SHOULD REMAIN GENERALLY SWLY OVERNIGHT AND THROUGH THE
DAY TOMORROW. THERE REMAINS SOME QUESTION ABOUT WIND SPEEDS.
PREVAILING SFC WINDS SHOULD REMAIN GENERALLY UNDER 10KT THROUGH
THE DAY AS A WEAK SFC PRESSURE GRADIENT WILL BE IN PLACE...BUT
WINDS ALOFT WILL BE IN THE INCREASE THROUGH THE DAY AS THE MID
LEVEL SYSTEM APPROACHES THE MIDDLE MISSISSIPPI VALLEY. MODEL
SOUNDINGS INDICATE THAT SWLY-WLY WINDS OF 15-20KT WILL MOVE OVER
THE AREA BY LATE MORNING AND THROUGH THE AFTERNOON. HOWEVER...WITH
THE ANTICIPATION OF INCREASING CLOUD COVER...LOW LEVEL MIXING MAY
NOT BE SUFFICIENT TO TAP THE STRONGER WINDS. SO...WHILE THERE
COULD BE OCNL GUSTS OF 12-14KT...DO NOT ANTICIPATE THAT GUSTS OF
THIS MAGNITUDE WILL BE FREQUENT.
THE NEXT CONCERN WILL BE ASSOCIATED WITH THE COLD FRONT PUSHING
SWD THROUGH WI AND DOWN LAKE MICHIGAN. THE LATEST GUIDANCE
SUGGESTS THAT THE FRONT WILL NOT REACH THE CHICAGO AREA TERMINALS
UNTIL AROUND MIDNIGHT AND A LITTLE LATER FOR RFD DUE TO THE FASTER
SURGE OF THE FRONT OVER THE LAKE. WINDS SHOULD TURN NELY FOLLOWING
THE FROPA AND INCREASE TO 10-15KT. NELY FLOW WILL ALSO DRAW LAKE
COOLED AIR INTO NERN IL/NWRN IN...AND CIGS SHOULD LOWER INTO LOWER
END MVFR LEVELS LATE TOMORROW NIGHT. THERE IS ALSO A CHANCE FOR
VIS RESTRICTIONS OF 3-5SM BR AS WELL.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM TO HIGH CONFIDENCE IN WIND TRENDS THROUGH TOMORROW EVENING.
* MEDIUM CONFIDENCE IN THE TIMING OF THE FROPA TOMORROW NIGHT AND
THE WIND SHIFT TO NELY.
* LOW IN WHETHER ANY SHOWERS WILL DEVELOP AS FAR NORTH AS THE
CHICAGO AREA TERMINALS ON SATURDAY AFTERNOON AND EVENING.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...NORTHEAST WINDS OVER 10 KT WITH PROBABLE MVFR CIGS IN THE
MORNING.
MONDAY...NORTHEAST WINDS.
TUESDAY-THURSDAY...CHANCE OF TSRA.
MTF
&&
.MARINE...
215 PM CDT
LARGE AREA OF HIGH PRESSURE CENTERED JUST SOUTH OF LAKE MICHIGAN
WILL SHIFT SOUTHEAST TONIGHT. A WEAK LOW PRESSURE SYSTEM IN SOUTH
CENTRAL CANADA WILL DEEPEN SOME TONIGHT AS IT PASSES JUST NORTH OF
THE UPPER GREAT LAKES REGION. THE PRESSURE GRADIENT INCREASES
OVERNIGHT INTO EARLY SATURDAY MORNING...ESPECIALLY ALONG THE
NORTHERN HALF OF THE LAKE. THIS WILL MAINTAIN SW FLOW
TONIGHT...WITH WINDS APPROACHING 25-30 KT FOR A BRIEF TIME IN THE
NORTH LATE TONIGHT. BEHIND THE LOW...HIGH PRESSURE BUILDS INTO
SOUTHERN ONTARIO AND SENDS A COLD FRONT SOUTH DOWN THE LAKE
SATURDAY AFTERNOON AND EVENING. ADDITIONALLY...AN AREA OF LOW
PRESSURE IN THE CENTRAL PLAINS WILL SLOWLY DRIFT EAST TO THE OHIO
VALLEY BY LATE SUNDAY THEN CONTINUE TO THE ATLANTIC SEABOARD
MONDAY. THIS WILL HELP MAINTAIN OR A PERIOD OF NORTH TO
NORTHEASTERLY WINDS. ADDITIONAL WEAKER LOW PRESSURE AREAS WILL
PUSH TOWARD THE GREAT LAKES NEXT WEEK...MAINTAINING A SOUTH
COMPONENT TO THE WIND WITH OCCASIONAL THUNDERSTORMS THROUGH MID
WEEK.
KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1154 PM CDT Fri Aug 15 2014
.UPDATE...
ISSUED AT 904 PM CDT FRI AUG 15 2014
A few weakening disturbances are set to move through central
Illinois through Saturday. The first is largely through Illinois
already, moving rapidly off to the east, and resulted in isolated
to scattered showers from around Galesburg to Lawrenceville
earlier in the evening. The next is moving ESE through Missouri at
this time producing widespread showers and a few thunderstorms.
HRRR model progs bring this into central IL over the next few
hours, again mainly affecting Galesburg to Lawrenceville southward
while weakening as instability fades with the loss of daytime
heating. By Saturday afternoon, yet another disturbance is
expected to approach as a deeper slow moving 500 mb trough and
surface low develop over northeast Missouri. Precipitable water
values over 2 inches inches are expected to be associated with the
system, so there will be a threat for heavy rain as this moves
across southern Illinois Saturday evening. Have updated forecast
to account for temperature, humidity and precipitation trends
over the next several hours.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 307 PM CDT FRI AUG 15 2014
Decaying MCS moving toward the CWA early this afternoon, with some
light showers being reported near Galesburg. Most precipitation
still west of the Mississippi River, with the HRRR showing it
reaching about as far east as Springfield late this afternoon before
diminishing. Latest LAPS soundings from Springfield and Jacksonville
showing a fair amount of dry air below 700 mb, so am not expecting a
lot of accumulation out of this.
Shortwave currently moving southeast out of South Dakota/Nebraska
starting to produce additional storms in Kansas, and this area of
storms should expand as the wave moves eastward and the low level
jet increases. HRRR and NAM show this next MCS approaching far
western Illinois by late evening, but the other high-res models such
as the ARW and NMM are a bit slower with arrival across the western
CWA after about 2-3 am. All models show the MCS diminishing during
the morning, but redevelopment taking place toward late afternoon in
the west near a surface low in southeast Iowa. Extensive cloud cover
should mitigate much of the severe weather potential, but
precipitable water values increasing to over 2 inches will result in
some locally heavy rains.
&&
.LONG TERM...(Saturday night through Friday)
ISSUED AT 307 PM CDT FRI AUG 15 2014
Occluded low pressure will reach western IL around 00z/7pm Saturday,
bringing abundant moisture with the potential for some heavy rains.
The latest model runs have shown a diminishing threat for strong
storms in western IL, and SPC has reduced the 5% threat area to just
west of a line from Rushville to Springfield. The threat for thunder
in general will remain low due to limited ice formation and only
weak instability. Limited afternoon sunshine after morning rain
showers will also help to keep instability in check for Saturday
evening. Rain will be likely during the evening southwest of
Lincoln, then expand to the Indiana border after midnight Sat night.
Likely rain will continue on Sunday east of I-55 as the slow moving
low pressure system moves to near LWV by 00z/7pm Sunday. Bufkit
sounding analysis shows better instability ahead of the low in our
southeast areas Sunday afternoon, with MUCAPE up to 1500 J/kg, but
confidence is low that storms will become very strong due to limited
sunshine once again.
Precipitable water values will remain very high through Sunday with
2" to 2.3" across most of central and southeast IL. Locally heavy
rainfall from Saturday through Sunday evening could push 2 day totals
between 2" and 3".
As the low pulls east of IL on Sunday night, we expect diminishing
precip chances from west to east, with a break in the rain expected
at least on Monday. The Canadian GEM still indicated lingering
rain in most of our area, so we left some slight chance PoPs for
Monday.
The next weather system will arrive quickly late Monday night and
Tuesday, with increasing precip chances NW of the IL Monday night.
Relatively good agreement of a warm front moving east across IL on
Tuesday prompted chance PoPs across the board. The upper trough will
deepen into IL on Tuesday night and Wed, with a trailing cold front
lingering across IL through Thursday, keeping rain chances
entrenched in the forecast through Thursday night. Warm and very
muggy air will dominate the mid week period with the rain chances,
as dewpoints remain in the low 70s and highs climb into the mid to
upper 80s.
Friday should bring a break in the rain as upper level ridging
develops bringing even warmer air into central IL the following
weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1154 PM CDT FRI AUG 15 2014
Light showers and local MVFR ceilings from around K1H2 to KGBG
southward this evening as low pressure deepens to the west over
southern IA/northern MO. As the low moves slowly toward central
IL, isold TSRA will be able to develop, however any MVFR
cigs/VSBYS look to be too localized for mention in area TAFs. A
series of disturbances associated with the low pressure system
will bring periods of redevelopment of showers through the
remainder of the 24-hour TAF period, with ceilings just above MVFR
thresholds. There may be a break in shower activity from around
16Z-22Z, but timing is too uncertain for explicit mention of a
break in showers, and daytime heating will bring an increasing
threat for thunderstorms. Time-height plots show very little
improvement in ceilings after lowering to around 4-5 kft AGL
overnight.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ONTON
SHORT TERM...GEELHART
LONG TERM...SHIMON
AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1228 PM EDT SAT AUG 16 2014
.SYNOPSIS...
ISSUED AT 1119 AM EDT SAT AUG 16 2014
THE CLOUDS WILL CONTINUE TO COVER THE REGION LEADING TO MOSTLY
CLOUDY TO CLOUDY SKIES FOR TODAY AND TONIGHT. A LOW PRESSURE
MOVING IN FROM THE WEST TO SOUTHWEST AND A COLD FRONT APPROACHING
FROM THE NORTH WILL GIVE THE REGION A CHANCE FOR SOME RAIN TODAY
AND TONIGHT. HIGH TEMPERATURES TODAY WILL BE IN THE UPPER 70S AND
LOW TEMPERATURES TONIGHT WILL RANGE FROM THE LOWER 60S IN SOUTHERN
MICHIGAN TO THE UPPER 60S NEAR THE OHIO RIVER.
&&
.UPDATE...
ISSUED AT 1215 PM EDT SAT AUG 16 2014
GRIDS WERE UPDATED EARLIER TO REFLECT NORTHERN FRINGE OF AN AREA
OF SHOWER CLIPPING PORTIONS OF JAY...BLACKFORD AND GRANT COUNTIES.
THIS WILL BE LONG GONE BY 18Z WITH ATTENTION SHIFTING BACK TO THE
WEST. 13Z HRRR WAS THE ONLY MODEL TO BE EVEN CLOSE ON LAYOUT OF
CURRENT PRECIP OVER THE AREA AND UPSTREAM. IF IT HOLDS
TRUE...WIDELY SCT SHOWERS/ISOL STORMS WILL POP ACROSS THE AREA
THIS AFTERNOON. MODELS PAST FEW DAYS HAVE ADVERTISED A RAPID
INCREASE IN LOW LEVEL MOISTURE AND THIS HAS COME TO FRUITION WITH
MANY AREAS IN THE SW BACK INTO ILLINOIS SEEING SFC DEWPOINTS JUMP
BY 10 DEGREES OR MORE JUST THIS MORNING. MOIST AIRMASS WILL REMAIN
IN PLACE UNTIL COLD FRONT...CURRENTLY DROPPING THROUGH
MICHIGAN...ENTERS THE AREA SUNDAY INTO MONDAY. SKY COVER WAS
INCREASED DRAMATICALLY WITH THE UPDATE AS LARGE SHIELD OF MID
CLOUDS WAS OVERSPREADING THE AREA. ONCE IT SETTLES IN...MOSTLY
CLOUDY TO CLOUDY SKIES SHOULD PREVAIL. LIMITED HEATING IS
OCCURRING UPSTREAM UNDER THE CLOUD CANOPY. FORECAST HIGHS MAY END
UP A TAD TOO HIGH AND WILL EVALUATE WITH NEXT GRID UPDATE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM EDT SAT AUG 16 2014
A COUPLE OF SYSTEMS WILL IMPACT THE WEATHER TODAY AND TONIGHT OVER
THE FORECAST AREA. A SURFACE LOW WAS OVER SOUTHERN IOWA WITH A VERY
MOIST FLOW OF HIGH PRECIPITABLE WATER SURGING NORTHEAST INTO A
DEVELOPING CONVECTIVE COMPLEX OVER SOUTHERN IOWA INTO NORTHERN
MISSOURI. SATELLITE CLOUD TOP TEMPERATURES WERE QUITE COLD AND WERE
STILL COOLING AS OF 3 AM EDT. THE WRF/ARW APPEARS TO BE HANDLING
THIS SYSTEM THE BEST...WHICH INCLUDES A EAST/SOUTHEAST TRACK WHICH
WILL KEEP THE BULK OF THIS SYSTEM TO THE SOUTH OF THE FORECAST AREA.
HOWEVER...LIMITED LOW LEVEL THETA E CONVERGENCE BY MID AFTERNOON
COULD BE SUFFICIENT WITH DAYTIME HEATING TO SUPPORT THUNDERSTORM
DEVELOPMENT. HAVE ELIMINATED RAIN/STORM CHANCES THIS MORNING...AND
LOWERED CHANCES THIS AFTERNOON. A COLD FRONT WILL MOVE SOUTH TODAY
AND SHOULD REACH THE NORTHERN PART OF THE FORECAST AREA BY LATE
TONIGHT. HAVE INCLUDED SOME LOW CHANCES FOR STORMS IN THE VICINITY
OF THIS FRONT. SEVERE WEATHER PARAMETERS DO NOT SUPPORT SEVERE
STORMS TODAY OR TONIGHT.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 346 AM EDT SAT AUG 16 2014
LEAD SW DISTURBANCE OVR NWRN MO THIS MORNING WILL TURN SHIFT EWD
SHRT TERM THEN SEWD TO BEGIN THIS PD IN RESPONSE TO WELL DEMARCATED
SYS SEEN IN VAPOR DIGGING THROUGH WRN/SWRN PERIPHERY OF DEEP CYCLONE
OVR SERN QB. THIS IN TURNS LEADS TO A CONTD SWD SUPPRESSION OF
AFOREMENTIONED SYS WELL SOUTH THROUGH THE OH RVR VALLEY THROUGH MON
AS SEEN ALL MODEL GUIDANCE NOW AND POSES SOME QUANDARY WRT POPS GOING
FORWARD. STG MODEL BASED CLUSTERING RECOMMENDS ERODING GOING POPS
THROUGH MON NIGHT IN ASSOCN/W THIS SYS.
MORE SIG TROUGH UPSTREAM OVR THE NRN ROCKIES FOLLOWS EWD INTO THE
NRN LAKES TUE. HWVR PER GENERAL SWD NOTED HGT SUPPRESSION ALOFT
CONCERNED THIS PD MAY BUST AS WAVY FNTL BNDRY SETS UP WELL SOUTH OF
LOCAL AREA AND WALLS OFF MORE SIG NWD LL MSTR RTN. WILL HOLD
W/TRUNCATED LOW CHC MENTION TUE-FRI IN ADHERENCE TO SURROUNDING
COLLAB YET SURMISE MUCH OF THIS PD MAY END UP DRY. BEST HOPE
PREDICATED ON GEM/EC BLEND WOULD BE TUE AFTN AND THU NIGHT.
OTRWS SIG WARMING TREND ON TAP AS BROAD UPR RIDGE EXPANDS ACRS THE
SRN US ESP LT PD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1215 PM EDT SAT AUG 16 2014
AREA OF SHOWERS WAS PASSING WELL SOUTH OF KFWA AS OF 16Z. RADAR
WAS SHOWING WIDELY SCATTERED SHOWERS TRYING TO DEVELOP ACROSS
EASTERN ILLINOIS INTO WESTERN INDIANA. STILL POTENTIAL FOR WIDELY
SCT SHOWERS...RUMBLES OF THUNDER AND BRIEF PERIOD OF MVFR
CIGS/VSBY ASSOCIATED WITH THESE. HOWEVER DURATION AND DIRECT
IMPACT AT THIS TIME TOO QUESTIONABLE TO INTRODUCE INTO TAFS.
ADDITIONAL CHANCES FOR PRECIPITATION COULD OCCUR OVERNIGHT INTO
SUNDAY PRIOR TO 18Z AS SFC LOW PASSES SOUTH OF THE AREA AND COLD
FRONT DROPS IN FROM THE NORTH. WILL MAINTAIN DRY FORECAST THROUGH
18Z FOR NOW.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...FISHER
SYNOPSIS...LOTHAMER
SHORT TERM...SKIPPER
LONG TERM...T
AVIATION...FISHER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS TOPEKA KS
826 PM CDT Sun Aug 17 2014
.UPDATE...
Issued at 812 PM CDT SUN AUG 17 2014
Monitoring two MCS complexes tracking southeast over southern
Nebraska and north central Kansas. The Nebraska cluster maintains
a strong outflow boundary around 50 MPH gusting out ahead of the
main line showing a history of 60 to 70 mph winds. Thunderstorm
cluster in Kansas has recently reported wind gusts near 60 mph.
Environment ahead of the system is characterized currently by 3500
J/KG of MLCAPE and effective shear increasing to near 30 KTS as a
southwesterly LLJ ramps up over north central Kansas. Current thinking
is similar to latest runs of the HRRR depicting the two clusters
converging as they track south and east over the CWA. Have therefore
increased precip chances over north central Kansas. Instability gradient
weakens towards central and eastern portions of northeast Kansas
and would expect the cluster to weaken in severity between
midnight and 7 AM. Between now and midnight, slight risk of severe
weather was expanded across north central areas where wind gusts
between 50 and 60 mph and small hail are possible.
&&
.SHORT TERM...(This Evening through Monday)
Issued at 343 PM CDT SUN AUG 17 2014
Water vapor imagery showing next shortwave trough and associated
frontal boundary moving thru northwest NE. Thunderstorms have
developed over north central NE and should propagate southeastward
within moisture axis situated across central NE into far northern
KS that will lift slowly northward through the night. Expect NE
convection to weaken later this evening with the loss of heating and
weaker shear further south towards the KS border. Will still however
keep the high chance pops near the NE border and decrease southward
in weaker warm air advection. The most likely period will be near
the state line towards sunrise in the far northeast corner. Lows
tonight will be in the middle to upper 60s. More mixing and
increasing clouds should limit fog potential tonight.
Front to the north will move southeast and bisect the cwa northeast
to southwest by mid to late afternoon. Axis of higher cape will set
up along and ahead of the front. Although the shear along the front
will not be as strong as further north and a capping inversion will
be in place...expect afternoon heating and weak convergence along
the front to allow at least some isolated thunderstorms to develop.
If they do...a deeply mixed atmosphere with temps well into the
middle and upper 90s would favor potential strong wind gusts with
any convection that forms. Will keep highest chance pops along and
ahead of the front...or primarily just north and west of the
Turnpike.
.LONG TERM...(Monday Night through Sunday)
Issued at 343 PM CDT SUN AUG 17 2014
Expect scattered convection Monday evening as the frontal along the
frontal boundary as it slowly moves southeast. NAM showing MUCAPE
around 5000 J/KG with around 35 to 40kts of bulk shear into the
early evening hours. Could see a few strong to severe storms with
strong wind gusts the main hazard. The front should sag south of the
CWA Tuesday morning before moving northward as a warm front Tuesday
afternoon and Tuesday night. Isentropic lift over the warm front
should generate elevated thunderstorms mainly across the northern
CWA. Areas near Highway 36 will have a small chance of morning
thunderstorms on Wednesday.
Wednesday night through Saturday will see ridge building over the
Southern and Central Plains. Periodic waves will move through the
flow and models differ on timing and resultant precipitation
placement. Will continue with low end chances of precipitation,
mainly nocturnal. GFS and ECMWF diverge with the timing of an upper
level trough with the GFS keeping the upper trough over the western
states while the ECMWF is much further east over the central U.S..
Will go dry on Sunday given the large differences for now.
Temperatures will be above normal through much of the period.
&&
.AVIATION...(For the 00Z TAFs through 00Z Monday Evening)
Issued at 638 PM CDT SUN AUG 17 2014
Monitoring the evolution of TSRA over western Kansas and central
Nebraska. Latest guidance is beginning to trend toward convection
weakening west of KMHK by 12Z. Confidence was not high enough to
mention thunder at KMHK at this time. Second concern is fog
potential before cloud cover arrives. MVFR to IFR fog is possible
at KTOP after 09Z while increased winds and cloud cover at KMHK/KFOE
may hinder lower visibilities. Fog is expected to dissipate around
14Z as mixing increases.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Bowen
SHORT TERM...63
LONG TERM...53
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS GOODLAND KS
528 PM MDT SUN AUG 17 2014
.SHORT TERM...(THIS AFTERNOON THROUGH MONDAY)
ISSUED AT 121 PM MDT SUN AUG 17 2014
EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS CONTINUE TO SHOW
PERSISTENT RIDGE IN PLACE ACROSS THE SW US. A SHORTWAVE TROUGH IS
EVIDENT OVER NORTHERN COLORADO...WITH H7 TROUGH ON LATEST RAP JUST
OVER THE CENTRAL ROCKIES. RADAR AND VIS SATELLITE SHOW ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS ALREADY DEVELOPING ALONG SURFACE
TROUGH AXIS AHEAD OF UPPER TROUGH OVER OUR SW CWA.
HRRR HAS A REASONABLE HANDLE ON CURRENT COVERAGE AND INDICATED
ACTIVITY MAINLY REMAINING ALONG AND EAST OF A TRIBUNE TO FLAGLER
LINE. MODERATE INSTABILITY IS IN PLACE WITH ML CAPE IN THE 1500-
3000 J/KG RANGE. CIN IS STILL HIGH ACROSS THE EASTERN HALF OF THE
CWA...HOWEVER AS SHORTWAVE TROUGH MOVES EAST LATER THIS AFTERNOON
AND EVENING ML CINH SHOULD WEAKEN ALLOWING FOR ACTIVITY TO SPREAD
EASTWARD. COVERAGE IS STILL A QUESTION WITH DRY INVERTED V TYPE
MOISTURE PROFILES...HOWEVER WITH LARGE SCALE FORCING INCREASE AND
GOOD BL MOISTURE IN PLACE WE SHOULD BE ABLE TO SEE SCATTERED
ACTIVITY DEVELOP. THERE IS AT LEAST AN ELEVATED SEVERE THREAT
CONSIDERING THE FAVORABLE CAPE AND EXPECTATION OF EFFECTIVE SHEER
INCREASING LATER THIS AFTERNOON/EVENING AS TROUGH MOVES INTO THE
REGION. PROFILES WOULD ALSO SUPPORT POTENTIAL FOR MICROBURST
POTENTIAL...WHICH IS ALSO SUPPORTED BY DCAPE VALUES AROUND 1800
J/KG. AS SHORTWAVE TROUGH SHIFTS EAST A WEAK FRONTAL PASSAGE WILL
SLIGHTLY COOL TEMPS ALOFT TONIGHT AND PRECIP SHOULD COME TO AN END
ACROSS THE EAST AFTER MIDNIGHT.
MONDAY...WITH ELEVATED FRONT ACROSS THE NORTH...AND WASHED OUT
FRONT/SURFACE BAROCLINIC ZONE IN THE SOUTH THUNDERSTORM
REDEVELOPMENT WILL BE POSSIBLE ACROSS THE CWA MONDAY AFTERNOON.
ANOTHER WEAK VORTICITY MAX WILL ROTATE JUST NORTH OF THE CWA
MONDAY AFTERNOON/EVENING...WHICH COULD ALSO HELP WITH THUNDERSTORM
INITIATION. PRECIP SIGNAL IS STRONGEST ACROSS THE SOUTHERN CWA
THROUGH MONDAY AFTERNOON ALONG BAROCLINIC ZONE AS IS LIFTS
NORTH...WITH BETTER COVERAGE TOWARDS LATE AFTERNOON IN THE SOUTH.
HIGH TEMPS MONDAY SHOULD BE SLIGHTLY COOLER THAN TODAY...THOUGH
THEY WILL REMAIN ABOVE NORMAL WITH MOST LOCATIONS IN THE LOW-MID
90S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 227 PM MDT SUN AUG 17 2014
SHOWER/THUNDERSTORM ACTIVITY SHOULD CONTINUE ACROSS THE REGION
MONDAY EVENING BEFORE COMING TO AN END EARLY TUESDAY MORNING. AT
FIRST...MAIN ACTIVITY SHOULD MOVE IN FROM NORTH CENTRAL COLORADO
UNDER WEST-NORTHWEST FLOW. GFS CONDENSATION PRESSURE DEFICITS AND
WINDS AT 320K INDICATE THAT ADDITIONAL ELEVATED STORM DEVELOPMENT IS
POSSIBLE BY MIDNIGHT AS MAIN SHORTWAVE TROUGH PASSES THROUGH.
DECIDED TO KEEP CHANCE POPS GOING THROUGH MOST OF THE NIGHT BEFORE
WANING EARLY TUESDAY MORNING...BETWEEN 3-6 AM MDT. SOME OF THESE
STORMS COULD BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS AS THE
MAIN THREAT...TRANSITIONING TO PRIMARILY A LARGE HAIL THREAT WITH
THE OVERNIGHT ELEVATED THUNDERSTORM ACTIVITY.
THROUGH THE REST OF THE EXTENDED FORECAST PERIOD...A PERSISTENT
UPPER LEVEL PATTERN IS THE MAIN STORY BEFORE A PACIFIC NORTHWEST
TROUGH BREAKS THE RIDGE DOWN TOWARDS NEXT WEEKEND. FOR EACH DAY...
SHOWERS AND STORMS ARE POSSIBLE AS WEAK UPPER LEVEL DISTURBANCES
PASS OVER THE NORTHERN PERIPHERY OF THE SOUTHWESTERN U.S. RIDGE.
STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE TUESDAY WITH CAPE OF
2000-2500J/KG ALONG AND NORTH OF INTERSTATE 70...850-500 MB LAPSE
RATES AROUND 8 C/KM AND 0-6 KM BULK SHEAR AROUND 30-35 KTS. SOME
DRIER BOUNDARY LAYER AIR MOVES INTO THE REGION FROM THE WEST FOR
WEDNESDAY AND THURSDAY...LIMITING SEVERE CHANCES SOME BY DECREASING
AVAILABLE MOISTURE AND ATMOSPHERIC INSTABILITY.
AS FOR TEMPERATURES...HOT WEATHER IS EXPECTED TO PERSIST UNTIL THE
RIDGE BEGINS TO BREAK DOWN NEXT WEEKEND. DID LOWER MIN TEMPERATURES
A TOUCH BELOW MODEL GUIDANCE BASED ON RECENT TRENDS OBSERVED AND
COOL THUNDERSTORM OUTFLOWS LIKELY EACH EVENING. MODEL GUIDANCE...
ESPECIALLY THE EUROPEAN...SUGGESTS THAT A COLD FRONT PASSAGE IS
POSSIBLE BY THE END OF THE WEEK. MODEL AGREEMENT IS FAIRLY POOR WITH
THE GFS SUGGESTING THE HOT WEATHER WILL REMAIN. THEREFORE...DID NOT
MAKE ANY LARGE CHANGES TO THE EXTENDED FORECAST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 525 PM MDT SUN AUG 17 2014
CONDITIONS WILL REMAIN VFR AT KGLD AND KMCK FOR THE NEXT 24 HOURS.
AN ISOLATED STORM COULD BRING CONDITIONS DOWN TO MVFR BRIEFLY
THIS EVENING AT BOTH SITES. OTHERWISE WIND WILL BE LIGHT AND
VARIABLE OVERNIGHT AND THEN TURN NORTHERLY MONDAY MORNING BEHIND A
FRONTAL PASSAGE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...FS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
230 PM MDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 230 PM MDT SAT AUG 16 2014
EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS SHOWS 595 DM RIDGE
CENTERED OVER SW US...WITH DIFFLUENT FLOW OVER THE NORTHERN PLAINS
AHEAD OF A CLOSED LOW OVER THE SOUTHERN CANADIAN ROCKIES. AT THE
SURFACE A COLD FRONT THAT MOVED INTO THE CWA LAST NIGHT ANS SHIFTED
EAST WITH WEAK CONVERGENCE ALONG A TROUGH AXIS EXTENDING ACROSS
EASTERN COLORADO.
MODERATE INSTABILITY IS IN PLACE ACROSS THE EASTERN HALF OF THE CWA
WITH ML CAPE VALUES IN THE 1000-2000 J/KG RANGE. LOWER VALUES AROUND
500 J/KG ARE IN PLACE ALONG THE TROUGH AXIS WHERE BETTER FOCUS FOR
THUNDERSTORM INITIATION IS EXPECTED. HIGHER CINH WAS EXPECTED TO
LIMIT INITIATION IN THE EAST...HOWEVER EXTENSIVE CU FIELD NOW IN
PLACE WITH BETTER VERTICAL EXTENT THAT WOULD BE EXPECTED IF AIR
MASS WAS COMPLETELY INHIBITED. WHERE THUNDERSTORMS HAVE DEVELOPED
IN THE WEST WILL REMAIN MOST LIKELY AREA FOR CONVECTION ALONG WEAK
CONVERGENCE ZONE...HOWEVER I COULDNT RULE OUT ISOLATED
THUNDERSTORM ACTIVITY FURTHER EAST WERE CAP TO WEAKEN...ESPECIALLY
WITH WESTERN EDGE OF FRONT NEAR OUR EASTERN CWA BORDER. HAVE
EXTENDED AREA OF SLIGHT CHANCE POPS AND BUMPED UP COVERAGE IN THE
SW. SEVERE THREAT REMAINS VERY LOW WITH WEAK SHEER...HOWEVER IF A
BETTER UPDRAFT WERE TO DEVELOP IN THE EAST WHERE BETTER CAPE
PROFILES EXIST THEN SEVERE HAIL/WIND COULD BE THREATS.
BETTER THUNDERSTORM COVERAGE IS EXPECTED BY MID-LATE AFTERNOON
SUNDAY AS A WEAK SHORTWAVE MOVES JUST NORTH OF THE CWA. MODELS HAVE
A DECENT PRECIP SIGNAL OVER OUR CWA...DESPITE DRY SOUNDINGS...SO
CHANCE POPS WERE RETAINED. THUNDERSTORMS WILL TEND TO BE
ELEVATED..HOWEVER EFFECTIVE SHEER AROUND 35KT AND MODERATE MU CAPE
IN THE 2000-2600 J/KG WOULD BE SUPPORTIVE OF A ELEVATED SEVERE
WIND/HAIL THREAT WITH STORMS THAT DEVELOP. WIND MAY ACTUALLY BE THE
GREATER THREAT CONSIDERING THE INVERTED V PROFILES IN PLACE.
SOUTHERLY FLOW SHOULD BRING GOOD WAA BACK TO THE CWA...AND TEMPS
SHOULD BE AS WARM IF NOT WARMER AS TODAY WITH VALUES IN THE MID-
UPPER 90S.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 230 PM MDT SAT AUG 16 2014
A PERSISTENT UPPER LEVEL PATTERN WILL REMAIN DRAPED ACROSS THE
FORECAST AREA THROUGHOUT THE EXTENDED FORECAST PERIOD. THIS MEANS A
CONTINUATION OF THE ABOVE NORMAL TEMPERATURES AND THUNDERSTORM
CHANCES EACH AFTERNOON.
FOR SUNDAY NIGHT...A STRONG SHORTWAVE WILL PROGRESS ACROSS THE
NORTHERN GREAT PLAINS. SOME ENERGY SHOULD PASS OVER THE TRI-STATE
REGION...LEADING SCATTERED THUNDERSTORMS. WITH THIS DISTURBANCE AND
ASSOCIATED STRONGER WINDS MOVING THROUGH...THERE IS AN INCREASE IN
WIND SHEAR. WITH ATMOSPHERE INSTABILITY/CAPE UP TO 2000-2500
J/KG...THERE COULD BE A MORE ORGANIZED THREAT FOR SEVERE
WEATHER...ESPECIALLY EAST OF THE COLORADO BORDER. LARGE HAIL AND
DAMAGING WINDS WOULD BE THE MAIN THREATS AS BOUNDARY LAYER MOISTURE
IS NOT SUPPORTIVE OF A TORNADIC ENVIRONMENT. MOST OF THE
THUNDERSTORM ACTIVITY SHOULD LEAVE THE AREA BY MIDNIGHT AS THIS WILL
BE A FAST MOVING SHORTWAVE.
FOR MONDAY AFTERNOON/EVENING AND TUESDAY AFTERNOON/EVENING...
ADDITIONAL UPPER DISTURBANCES LEAD TO CONTINUED CHANCES FOR
STRONG/SEVERE THUNDERSTORMS. TUESDAY APPEARS HAVE A SLIGHTLY BETTER
CHANCE OF CONVECTIVE ACTIVITY AS THERE ARE SOME QUESTIONS ABOUT
ATMOSPHERE INSTABILITY MONDAY AND THE EFFECT THAT SUNDAY NIGHTS
CONVECTION WOULD HAVE ON THE ENVIRONMENT. LARGE HAIL AND DAMAGING
WINDS ARE ONCE AGAIN THE PRIMARY THREATS.
FOR WEDNESDAY AND BEYOND...DISAGREEMENT WITHIN THE MODEL GUIDANCE
LEADS TO LOWER CONFIDENCE IN THE TIMING AND LOCATIONS FOR BEST
THUNDERSTORM CHANCES. THERE COULD BE STORMS EACH DAY WITH THE
STAGNANT PATTERN AND CONTINUED UPPER LEVEL DISTURBANCE PASSAGES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1120 AM MDT SAT AUG 16 2014
VFR CONDITIONS SHOULD PREVAIL AT BOTH KGLD AND KMCK TERMINALS
THROUGH THE TAF PERIOD. LIGHT FOG WITH VIS AROUND 6SM (MAYBE LESS)
WILL BE POSSIBLE AT KMCK...SIMILAR TO WHAT OCCURRED THIS MORNING.
THERE ISNT A STRONG SIGNAL IN GUIDANCE FOR THIS...SO HAVE LIMITED
MENTION TO 6SM GROUP AT 11-15Z. WITH WEAK SURFACE PRESSURE
GRADIENT OVER BOTH TERMINALS WINDS WILL REMAIN ERRATIC THROUGH THE
PERIOD...GENERALLY 6KT OR LESS. EVENTUALLY WINDS SHOULD SHIFT TO
MORE OF A SOUTHEAST DIRECTION LATE IN THE TAF PERIOD...AGAIN
AROUND 6KT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...DR
AREA FORECAST DISCUSSION
NWS JACKSON KY
1037 PM EDT SUN AUG 17 2014
.UPDATE...
ISSUED AT 1035 PM EDT SUN AUG 17 2014
UPDATED THE FORECAST TO BETTER REFLECT CURRENTS CONDITIONS AND MODEL
TRENDS. THE ISOLATED ACTIVITY CURRENTLY OVER THE AREA WILL BE
INCREASING AS THE TROUGH APPROACHES FROM THE WEST. SO FAR
PRECIPITATION AMOUNTS OVER CENTRAL KENTUCKY HAVE CONFIRMED THAT A
FLASH FLOOD WATCH IS NOT NEEDED. ALSO THE HRRR AND NEW NAM WOULD ALSO
BE SUPPORTIVE ON NOT ISSUING A FLASH FLOOD WATCH AT THIS TIME. THE
REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 905 EDT SUN AUG 17 2014
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. SOME ISOLATED TO SCATTERED SHOWERS ARE CURRENTLY MOVING
ACROSS THE AREA WITH THE HEAVIER PRECIPITATION OVER CENTRAL KENTUCKY.
THIS HEAVIER AREA WILL BE MOVING INTO THE AREA AFTER 11 PM TONIGHT.
LOOKING AT THE MODELS AND THE RAINFALL AMOUNTS UPSTREAM...THE CONCERN
FOR LOCALIZED FLOODING IS A LITTLE LOWER THAN EARLIER THINKING. THERE
STILL COULD BE SOME VERY LOCALIZED ISSUES WILL SOME CREEKS...DITCHES
AND LOW WATER CROSSING RUNNING FULL DURING THE OVERNIGHT AND MORNING
HOURS. THE REST OF THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 303 PM EDT SUN AUG 17 2014
MAIN HEAVY RAIN THREAT WILL BE FROM THIS EVENING INTO MONDAY
MORNING. WIDESPREAD 1 INCH RAINFALL AMOUNTS ARE FORECAST TONIGHT INTO
MONDAY WITH ISOLATED SPOTS RECEIVING IN EXCESS OF 2 INCHES. BASED ON
CURRENT RADAR TRENDS AND EXPECTED DEVELOPMENT THIS EVENING THE
HEAVIEST RAINS WILL LIKELY FALL JUST SOUTH OF KY OVER TN.
LOW PRESSURE OVER SOUTHWEST INDIANA AT SURFACE AND ALOFT WILL TRACK
SLOWLY EAST ACROSS KY TONIGHT...BUT IS NOT EXPECTED TO MOVE EAST OF
OUR AREA UNTIL BETWEEN 12Z AND 18Z MONDAY. AS THE LOW MOVES EAST THE 8H
JET WILL RAMP UP AND LIFT WILL INCREASE LATER TONIGHT. MODELS ARE IN
GOOD AGREEMENT WITH PWS FORECAST AROUND 2 INCHES. THIS IDEA IS
SUPPORTED BY GOES SOUNDER DATA THAT WAS AVAILABLE PRIOR TO THE
WIDESPREAD CLOUD COVER. AFTER COORDINATION WITH NEIGHBORING FORECAST
OFFICES WILL NOT BE ISSUING A FLASH FLOOD WATCH AT THIS TIME...BUT
THE SITUATION WILL NEED TO BE MONITORED CLOSELY TONIGHT INTO MONDAY
MORNING. CONVECTION WILL BE LESS ORGANIZED AFTER THE LOW MOVES
EAST OF OUR AREA ON MONDAY...BUT A CHANCE OF SHOWERS AND THUNDERSTORMS
WILL LINGER INTO MONDAY NIGHT ESPECIALLY IN THE EAST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 303 PM EDT SUN AUG 17 2014
MEDIUM RANGE MODELS POINT TO A RETURN TO A MORE TYPICAL SUMMER-LIKE
PATTERN FOR THE SOUTHERN AND CENTRAL APPALACHIANS AS A RIDGE OF HIGH
PRESSURE BUILDS EASTWARD FROM THE SOUTHERN PLAINS IN THE SOUTHEAST
CONUS. HERE AT NWS JACKSON...OUR DAILY AVERAGE TEMPERATURE HAS BEEN
NORMAL OR BELOW EVERY DAY SINCE JULY 23RD. THAT TREND WILL LIKELY
END BY MID WEEK AS TEMPERATURES MODERATE TO SLIGHTLY ABOVE NORMAL
LEVELS. DEWPOINTS AROUND 70 WILL MAKE IT FEEL LIKE SUMMER FOR SURE.
DESPITE THE BUILDING RIDGE ALOFT...A QUASI-STATIONARY FRONTAL
BOUNDARY...A WEAKENED FEATURE LEFTOVER FROM THE SHORT TERM
PERIOD...WILL REMAIN IN OUR VICINITY PRETTY MUCH THROUGHOUT THE LONG
TERM PERIOD. THIS FRONT WILL WAFFLE NORTH AND SOUTH BUT LIKELY
REMAIN CLOSE ENOUGH TO BE A FOCUS FOR DAILY SHOWER AND THUNDERSTORM
CHANCES WITH THE WARM AND UNSTABLE AIRMASS IN PLACE. THIS SHOULD BE
TYPICAL SCATTERED ACTIVITY WITH GREATEST COVERAGE DURING THE
AFTERNOON AND EARLY EVENING HOURS...BUT MAY POTENTIALLY BE AUGMENTED
BY ONE OR TWO ORGANIZED THUNDERSTORM COMPLEXES DROPPING DOWN FROM
THE NORTHWEST ON THE NORTHEAST SIDE OF THE BUILDING UPPER RIDGE.
STORM CHANCES DECREASE SLIGHTLY NEXT WEEKEND AS THE UPPER RIDGE
AMPLIFIES A BIT...BUT CANNOT BE TOTALLY REMOVED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 905 PM EDT SUN AUG 17 2014
A BAND OF SHOWERS WITH SOME VERY ISOLATED EMBEDDED THUNDERSTORMS
ARE MOVING TOWARD THE AREA. THESE SHOWERS WILL BE CAPABLE OF SOME
HEAVY RAINFALL RATES...SO THEY WILL LIKELY TAKE THE VSBY DOWN TO IFR
LEVELS DURING THE HEAVIEST SHOWERS. THE CIGS WILL BE UP AND DOWN AS
THE SHOWERS MOVE ACROSS THE AREA. EXPECTING SOME VALLEY FOG AND MIST
THIS MORNING AND CONDITIONS WILL NOT GET TO MVFR UNTIL AROUND 18 TO
20Z TOMORROW AS THE SYSTEM CONTINUES MOVING TO THE EAST. FOR ROTARY
WING AIRCRAFT...SOME OF THE STRONGER STORMS TONIGHT AND TOMORROW MAY
CONTAIN SOME SMALL HAIL OR GRAUPEL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...SBH
LONG TERM...ABE
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
959 PM CDT SUN AUG 17 2014
.DISCUSSION...
DIFFICULT UPDATE THIS EVENING AS WE CONTINUE TO DEAL WITH A WEAK
TO MODERATELY UNSTABLE AIRMASS IN PLACE...A SHORTWAVE NEAR THE
I-30 CORRIDOR OF NE TX/SE OK/SW AR AND INCREASING PRECIPITABLE
WATER VALUES FROM THE WEST ASSOCIATED WITH THE SHORTWAVE.
CONVECTION THUS FAR THIS EVENING HAS BEEN VERY UNEVENTFUL EXCEPT
FOR WIDELY SCATTERED CONVECTION ASSOCIATED WITH A SEABREEZE
BOUNDARY THAT MOVED A GOOD BIT FURTHER NORTH INTO DEEP EAST TEXAS
AND NORTH CENTRAL LOUISIANA COMPARED TO SATURDAY. AS OF THIS
WRITING...ALL CONVECTION HAS DISSIPATED BUT WE WILL CONTINUE TO
LOOK TO OUR NORTH AND WEST OVERNIGHT FOR THE POSSIBILITY OF
REDEVELOPMENT.
THE ARGUMENTS AGAINST REDEVELOPMENT INCLUDE THE FACT THAT A WEAK
WSW ORIENTED LOW LEVEL JET NEAR 20KTS IS VEERED A LITTLE MORE THAN
I WOULD LIKE TO SEE IT AND THAT WHILE PWATS SHOULD INCREASE
OVERNIGHT SLIGHTLY...MODELS ARE REALLY OVERDOING THE DEPTH OF
MOISTURE IN ASSOCIATION WITH THIS SHORTWAVE/SHEAR AXIS. THE GFS
CONTINUES TO BE USELESS AS IT SUFFERS FROM CONVECTIVE FEEDBACK
PROBLEMS AND THE LATEST HRRR HAS COME IN MUCH DRIER OVERNIGHT THAN
ITS PREVIOUS RUN SUGGESTED. HOWEVER...THE LATEST 00Z NAM SHOWS
QUITE A BIT OF REDEVELOPMENT OVERNIGHT MAINLY NORTH OF THE I-20
CORRIDOR ACROSS EXTREME NE TX/SE OK AND ESPECIALLY SW AR.
THIS LEADS TO A LOW CONFIDENCE FORECAST BUT ALL VARIABLES LEAD ME
TO RAISE POPS SLIGHTLY ACROSS OUR NORTHERN MOST ZONES AND TO TRIM
POPS BACK SLIGHTLY ACROSS THE I-20 CORRIDOR OF NE TX AND NORTHERN
LOUISIANA AS WELL AS POINTS SOUTH.
ONLY MADE SLIGHT CHANGES TO TEMPS OVERNIGHT AS SOME 02Z LOCATIONS
WERE ALREADY NEAR FCST MINS. OTHERWISE...ROUTINE DEWPOINT AND RH
GRIDS WERE ADJUSTED TO MIMIC CURRENT TRENDS...OTHERWISE NO OTHER
SIGNIFICANT CHANGES WERE MADE.
UPDATE OUT SHORTLY...13.
&&
.PREV DISCUSSION... /ISSUED 733 PM CDT SUN AUG 17 2014/
AVIATION...
A FEW TSTMS CONTINUE ACROSS PARTS OF DEEP E TX/AND W CENTRAL
LA...BUT RADAR TRENDS OVER THE LAST HALF HOUR OR SO INDICATE THAT
THESE STORMS ARE DIMINISHING. HOWEVER...STORMS MAY REDEVELOP
DURING THE OVERNIGHT/EARLY MORNING HOURS...ALTHOUGH SIGNIFICANT
DIFFERENCES IN FORECAST MODELS MAKES FOR QUITE A BIT OF
UNCERTAINTY. MVFR/PATCHY IFR STRATUS WILL BE POSSIBLE AROUND
SUNRISE YET AGAIN...WITH CIGS LIFTING BY AROUND MID MORNING.
/12/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 76 93 75 96 75 / 30 50 20 20 10
MLU 74 90 74 95 74 / 30 50 20 20 10
DEQ 72 94 71 95 72 / 40 20 10 0 10
TXK 75 93 73 95 74 / 40 40 10 10 10
ELD 74 92 73 95 74 / 40 50 20 20 10
TYR 75 94 74 96 75 / 30 40 10 0 10
GGG 75 94 74 96 75 / 30 40 10 10 10
LFK 75 94 75 96 76 / 20 30 20 20 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
13
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1008 PM EDT SUN AUG 17 2014
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL SLIDE OFF THE COAST TONIGHT. A COOL
FRONT WILL DROP SOUTH TOWARDS THE REGION LATE TONIGHT AND MONDAY.
LOW PRESSURE WILL MOVE ALONG THE FRONT FROM THE OHIO VALLEY
TOWARDS THE MID-ATLANTIC REGION LATE TONIGHT THROUGH MONDAY
NIGHT...BEFORE MOVING OFF THE COAST DURING TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
UPDATE OF THE POPS ACROSS THE MD EASTERN TO ACCOUNT FOR A WEAK WAVE
IN THE UPPER LEVELS WHICH IS PRODUCING SOME ISOLD TO SCT SHOWERS.
THE RAP AND HRRR BOTH HAVE A DECENT HANDLE ON THESE SHOWERS WHICH
COULD HOLD ON THROUGH AROUND 06Z. THE SHOWERS SHOULD BE LIMITED IN
OVERALL COVERAGE...BUT WILL TRAIN OVER A FEW LOCATIONS THROUGH
06Z. SHOWER ACTIVITY SHOULD DECREASE AND SHIFT OFF THE COAST
SHORTLY AFTER 06Z.
A TROF OF LO PRES WILL SLIDE OFF THE CST TNGT. SOME WEAK ENERGY
COMBINED WITH MARGINAL INSTABILITY COULD TRIGGER AN ISLTD SHOWER
OR TSTM THIS EVENG. OTHERWISE...GENERALLY PARTLY CLOUDY AND MILD
TNGT WITH LOWS RANGING FM THE MID 60S TO LWR 70S.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
WARM AND MORE HUMID MON THRU WED...AS WESTERLY (ZONAL) FLO ALOFT
DOMINATES THE REGION. AN AREA OF DEEPER LO LVL MOIST ASSOCIATED
WITH A MID LVL TROF AND SFC LO PRES WILL AFFECT THE REGION MON
AFTN INTO AT LEAST MIDDAY TUE. THUS...WILL HAVE THE HIGHEST POPS
(30-60%) FOR SHOWERS AND POSSIBLE TSTMS DURING THIS TIME PERIOD.
THE PRESENCE OF AN INCREASINGLY UNSTABLE AIRMASS AND PW VALUES
~1.75-2.00 INCHES WILL ALSO MEAN STRONGER SHOWERS OR TSTMS COULD
CONTAIN HEAVY RAINFALL. POPS DECREASE TO SLGT CHC OR NO CHC (14%)
LATE TUE INTO WED MORNG...DUE TO SUBSIDENCE BEHIND THE DEPARTING
WAVE OF LO PRES. MORE SHRTWV ENERGY IN WEAK UPR AIR TROFINESS WILL
RESULT IN SLGT (20%) TO SML CHC (30%) POPS ACRS THE AREA ON
WED...ESPLY IN THE AFTN/EVENG.
MAX TEMPS WILL MAINLY RANGE FM THE MID 80S TO NEAR 90 THRU THE
PERIOD...WITH MIN TEMPS RANGING FM THE MID 60S TO LWR 70S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BLOCKY PATTERN OVER ERN CANADA AND THE NRN ATLANTIC WILL RESULT IN
AN UNSETTLED WEATHER PATTERN THROUGH THE PERIOD. TEMPS WILL BE NEAR
SEASONABLE...LATE SUMMER NORMS.
SPLIT/BLOCKY FLOW IS TYPICALLY PROBLEMATIC FOR MEDIUM RANGE
GUIDANCE...AND THIS TIME IS NO EXCEPTION. CONTINUE TO TREND FORECAST
TOWARD THE ECMWF AND ENSEMBLE MEANS BASED ON RUN TO RUN CONSISTENCY
AND WPC GUIDANCE...BUT CONFIDENCE IS NOT HIGH ATTM. THIS GUIDANCE
REMAINS BTWN THE MORE AMPLIFIED 17/12Z GFS AND THE NEARLY ZONAL
17/12Z CANADIAN. WITH THAT SAID...FLOW AMPLIFIES OVER THE ERN CONUS
AS MID LEVEL HIGH PRESSURE BUILDS OVER THE GULF STATES.
MEANWHILE...ANOMALOUS HIGH PRESSURE BUILDS OVER ERN CANADA. SRN
STREAM ENERGY OVER THE GREAT LAKES/NE STATES WILL PUSH A SHORTWAVE
INTO THE NE STATES WITH TROUGHING EXTENDING SWD ALONG THE ERN
SEABOARD. QUASI-STATIONARY BOUNDARY WILL SETTLE ACROSS THE
MID-ATLANTIC REGION (ABOUT 100 MILES FARTHER SOUTH THAN 24 HOURS
AGO) DURING THE PERIOD AS FLOW ALOFT REMAINS GENERALLY WLY. THE
FRONT WILL BE THE FOCUS FOR SHOWERS/THUNDERSTORMS THRU THE PERIOD AS
WEAK PERTURBATIONS IN THE FLOW PRODUCE WAVES OF LOW PRESSURE ALONG
THE BOUNDARY. WARM/HUMID AIRMASS WILL BE IN PLACE WITH DEWPOINTS IN
THE UPPER 60S TO LOW 70S AND TYPICAL LATE SUMMER PWATS BTWN 1.5 AND
2 INCHES. HOWEVER...LACK OF CONFIDENCE FACTORS INTO RELATIVELY LOW
CHANCE POPS. CLIMO THIS TIME OF YEAR IS AROUND 20 PCT...BUT WILL GO
HIGHER DURING THE AFTERNOON (30-40%) AND NEAR CLIMO OVERNIGHT DUE TO
MOIST AND MARGINALLY UNSTABLE AIRMASS. IF THE TROUGH PUSHES OFFSHORE
FRI NIGHT-SAT...PERTURBATIONS IN THE NW FLOW COULD BRING ADDITIONAL
CHANCES OF PRECIP TO THE REGION THRU THE WEEKEND...ESPECIALLY IN THE
NE.
WARM THURS AND FRI WITH HIGHS IN THE UPPER 80S TO AROUND
90...COOLING OFF DUE TO CLOUDS/PRECIP THIS WEEKEND. LOW LEVEL
THICKNESSES YIELD TEMPS GENERALLY IN THE MID 80S SAT AND SUN.
OVERNIGHT LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S THRU THE
PERIOD.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH THE MAJORITY OF THE OVERNIGHT
PERIOD WITH SOME MVFR VIS POSSIBLE AT SKBY/KECG. A COLD FRONT
APPROACHES THE REGION FROM THE NORTH LATE TONIGHT AND STALLS ACROSS
THE AREA MONDAY AFTN. THE FRONT COUPLED WITH A WEAK SURFACE TROUGH
WILL INCREASE THUNDERSTORM CHANCES ACROSS THE AREA MON/MON NIGHT.
FOR TUESDAY...THE FRONT REMAINS STATIONARY ACROSS THE REGION
BRINGING A CHC FOR WIDESPREAD SHOWERS/STORMS.
&&
.MARINE...
UNSETTLED WEATHER PATTERN WILL PREVAIL OVER THE WATERS THRU THE
FORECAST PERIOD...BUT SCA CONDITIONS ARE NOT ANTICIPATED.
WEAK SFC TROUGH REMAINS OVER THE WATERS THIS AFTERNOON WITH WSW
WINDS AVG 5-10 KT AND WAVES/SEAS 1-2 FT. A COLD FRONT HAS DROPPED
INTO SRN PA LATE THIS AFTERNOON AS AN AREA OF LOW PRESSURE
PROPAGATES EWD OVER THE MID MS/LOWER OH VALLEY. THE FRONT WILL DROP
SWD TONIGHT OVER THE NRN WATERS AS HIGH PRESSURE BUILDS OVER NEW
ENGLAND. FLOW BECOMES NE ON THE BACKSIDE OF THE FRONT WITH WLY FLOW
TO THE SOUTH...REMAINING AOB 10 KT. SFC LOW WILL WEAKEN OVER THE
CNTRL APPALACHIANS AS A SECONDARY LOW DEVELOPS OVER THE WATERS. FLOW
WILL INCREASE SOUTH OF THE WATERS...BUT ANTICIPATE SPEEDS AROUND 10
KT TUES-TUES NIGHT. HIGH PRESSURE SLIDES OVER NEW ENGLAND
TUES...LOCATING OFFSHORE TUES NIGHT WEDS. MEANWHILE...LOW PRESSURE
REMAINS OVER THE WATERS. THE RESULT WILL BE PERIODS OF ONSHORE
FLOW...ESPECIALLY OVER THE NRN WATERS. NE FETCH WILL LIKELY PUSH
SEAS UPWARDS OF 3-4 FT...BUT NOT ANTICIPATING SCA CONDITIONS ATTM.
FRONTAL BOUNDARY REMAINS OVER THE REGION THRU THE WEEK...RESULTING
IN AN UNSETTLED WX PATTERN...BUT SUB-SCA CONDITIONS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMG
NEAR TERM...TMG/JAO
SHORT TERM...TMG
LONG TERM...SAM
AVIATION...DAP/JEF
MARINE...SAM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
737 PM EDT SUN AUG 17 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 332 PM EDT SUN AUG 17 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALF BTWN
A SLOWLY RETREATING...DEEP UPR TROF IN QUEBEC AND AN UPR RDG IN THE
PLAINS/UPR MS RIVER VALLEY. SFC HI PRES UNDER THIS RDG AXIS IS
LOCATED JUST NNW OF LK SUP. THE LLVL NE FLOW ON THE SRN FLANK OF
THIS HI IS FUNNELING SOME COOL...MOIST AIR INTO THE UPR LKS BLO
SHARP SUBSIDENCE INVRN ARND H85 AS SHOWN ON THE LOCAL 12Z RAOBS. THE
RESULT HAS BEEN A GOOD DEAL OF LO CLD COVER. THERE WAS EVEN SOME
DRIZZLE INTO THE EARLY AFTN OVER THE HIER TERRAIN OF THE NCENTRAL...
WHERE THE NE WIND PRESENTS A SHARPER UPSLOPE COMPONENT. BUT WITH
DAYTIME HEATING UNDER THE MID LVL DRY AIR AND SOME DRY H95-9
ADVECTION FM THE NE...THE LO CLDS ARE SHOWING SIGNS OF BREAKING
UP...ESPECIALLY IN AREAS THAT EXPERIENCE DOWNSLOPE FLOW. LOOKING TO
THE W...A VIGOROUS SHRTWV IN SRN SASKATCHEWAN IS MOVING EWD JUST N
OF THE CNDN BORDER AND TENDING TO SUPPRESS THE UPR RDG IN THE
PLAINS. THERE IS ANOTHER WEAKER SHRTWV AHEAD OF THIS FEATURE MOVING
THRU MN. CLDS ALONG WITH SHOWERS/A FEW TS ASSOCIATED WITH THIS
DISTURBANCE/OVERALL H85 THETA E ADVCTN IN THE LARGER SCALE SW FLOW
AHEAD OF THE STRONGER SASKATCHEWAN SHRTWV ARE APRCHG DULUTH EARLY
THIS AFTN.
MAIN FCST CONCERNS INTO THIS EVNG ARE FOCUSED ON LO CLD TRENDS.
TIMING/COVERAGE OF SHOWERS ASSOCIATED WITH PAIR OF UPSTREAM SHRTWVS
ARE THE CONCERNS FOR LATER TNGT AND MON.
LATE TODAY/TNGT...ALTHOUGH THE COMBINATION OF SOME LLVL DRY ADVCTN
AND DAYTIME HEATING MAY BREAK UP THE LO CLDS NOW IMPACTING THE CWA
THRU THIS AFTN...FAIRLY HI INVRN BASE OBSVD ON THE 12Z RAOBS WL
PROBABLY MAINTAIN BKN LO CLDS AT MANY LOCATIONS NOT IMPACTED BY
DOWNSLOPING FLOW AS THE SLOWLY RISING LCL WL REMAIN UNDER THE HIER
INVRN BASE. BUT THE LATEST TRENDS INDICATE THESE CLDS SHOULD BE
ALMOST COMPLETELY GONE BY 00Z. AFTER THIS EVNG...CLD COVER/SCT
SHOWERS NOW APRCHG DLH ARE LIKELY TO SPREAD INTO THE WRN CWA IN
ADVANCE OF LEAD SHRTWV AND WHERE STRONGER H85 THETA E ADVCTN WL
DVLP. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR E WHERE THERE IS
LIKELY TO BE A LONGER PERIOD OF MOCLR SKIES/LGT WINDS CLOSER TO SFC
HI MOVING FM ERN LK SUP INTO ADJOINING ONTARIO. ADDED SOME PATCHY
FOG TO THE FCST IN THIS AREA WHERE TEMPS ARE EXPECTED TO FALL BLO
THE CROSS OVER DEWPTS OBSVD THIS AFTN.
MON...MAIN SHRTWV NOW MOVING THRU SRN SASKATCHEWAN IS FCST TO MOVE
INTO MN DURING THE AFTN. ALTHOUGH SOME SCT SHOWERS ASSOCIATED WITH
THE LEAD DISTURBANCE/AREA OF H85 THETA E ADVCTN MAY SPREAD INTO THE
CENTRAL AND ERN CWA...THESE ARE MORE LIKELY TO WEAKEN WITH TIME AS
THE CLUSTER MOVES TOWARD THE SHRTWV RDG AXIS/DRIER MID LVL AIR ON
THE WRN FLANK OF THE SLOW MOVING QUEBEC TROF. MORE NMRS SHOWERS ARE
LIKELY TO MOVE INTO THE W HALF OF THE CWA IN THE AFTN UPON THE
ARRIVAL OF DEEPER MSTR/MORE VIGOROUS DYANMIC SUPPORT ASSOCIATED WITH
THE MORE VIGOROUS TRAILING SHRTWV IN THE PRESENCE OF DAYTIME
HEATING. WITH FCST MUCAPES NO HIER THAN 100-200 J/KG ASSOCIATED WITH
A GOOD DEAL OF CLD COVER/EXPECTED DAYTIME HI TEMPS MAINLY IN THE
60S...WL LEAVE OUT A MENTION OF TS EXCEPT OVER THE FAR W...WHERE THE
MORE UNSTABLE GFS HINTS MUCAPES MAY REACH 500 J/KG CLOSER TO THE
INCOMING DISTURBANCE/COLDER AIR ALF.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 332 PM EDT SUN AUG 17 2014
AT 00Z TUESDAY THE NEXT 500MB WAVE WILL BE SET UP ACROSS MN THROUGH
W ONTARIO. MID/LONG TERM MODELS INDICATE THAT THIS FEATURE WILL
DEVELOP INTO A LOW 12-18Z TUESDAY OVER E MN AND THE W HALF OF THE
MQT CWA. AT THAT POINT...LITTLE MOVEMENT WILL BE EXPECTED AT 500MB
UNTIL AFTER DAYBREAK WEDNESDAY...AS THE 500MB SITS AND SPINS ACROSS
UPPER MI AND LAKE SUPERIOR. THE SFC LOW SHOULD TRACK FROM N AND
CENTRAL MN AT 00Z TUESDAY NEAR THE WI/UPPER MI BORDER ON
TUESDAY...BEFORE EXITING ACROSS LAKE MI TUESDAY NIGHT...AND LOWER MI
ON WEDNESDAY. WITH UPPER MI STAYING ON THE N SIDE OF THE SFC LOW
EXPECT A PERIOD OF CLOUDY CONDITIONS...WITH AFTERNOON TEMPS ON
TUESDAY AVERAGING AROUND 5F BELOW THE SEASONAL NORMAL VALUES. THE
BEST CHANCE FOR PRECIP IS DIFFICULT TO PIN DOWN AT THIS POINT...AS
FCST MODELS VARY SIGNIFICANTLY WITH THE SMALLER SCALE FEATURES WITH
THIS DEVELOPING SYSTEM. WILL CONTINUE TO GO RELATIVELY GENERAL WITH
THE POPS AT THIS POINT. WILL KEEP TS POTENTIAL TO A MINIMUM...GIVEN
THE TRACK OF THE SFC LOW MAINLY TO OUR S...AND MU CAPE VALUES OVER
THE FAR W AOB 100J/KG FAR W TUESDAY MORNING. TUESDAY DURING THE DAY
DOESN/T LOOK MUCH MORE IMPRESSIVE...TOPPING OUT ALONG THE WI BORDER
GENERALLY AROUND 200 J/KG OR LESS /RESTRICTED TS MENTION TO CENTRAL
U.P./.
THE 500MB RIDGE WILL BRIEFLY BUILD OVERHEAD LATER WEDNESDAY INTO
EARLY THURSDAY. OUT OF THE WORK WEEK FROM TUESDAY ON...THIS SHOULD
BE THE DRIEST PERIOD. WILL TRY TO SHOW A BIT MORE IN OUR
FCST...DESPITE THE PW VALUES REMAINING 80-140 PERCENT OF NORMAL
/LOWEST E/.
THE CHANCE OF SHOWERS RETURN LATE THURSDAY INTO FRIDAY AS A
SHORTWAVE/TROUGH GLANCES THE AREA. TS MAY RETURN ON FRIDAY. EXPECT
WAA FRIDAY TO PUSH 850MB TEMPS UP TO 15-19C. IF CLOUDS AND PRECIP
CAN STAY TO A MINIMUM...SFC SHOULD SHIFT TO ABOVE NORMAL READINGS.
AS FOR THE OPEN HOUSE AT THE MQT NWS ON SATURDAY 10AM-2PM
EDT...THERE IS ENOUGH DISCREPANCIES AT THIS POINT IN THE FCST MODEL
DATA TO KEEP A GENERAL BLEND OR CONSENSUS GOING. BOTH THE GFS AND
ECMWF SHOW A 500MB LOW TO THE W OF UPPER MI AT 12Z.
HOWEVER...LOCATIONS VARY FROM N MANITOBA TO THE DAKOTAS...WITH A SFC
LOW OR TROUGH EITHER JUST TO OUR W OR OVER W UPPER MI. IF THE 17/00Z
AND 06Z GFS RUNS ARE CORRECT...WINDS NEAR 20KTS WILL BE POSSIBLE.
THE 12Z RUN DID DIMINISH THESE STRONG WINDS...DOWN TO AROUND 10KTS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 736 PM EDT SUN AUG 17 2014
CHALLENGING FCST SHAPING UP OVER THE NEXT 24HRS AS A COUPLE OF
DISTURBANCES MOVE INTO THE UPPER GREAT LAKES. INITIALLY...LOW CLOUDS
CONTINUE TO PLAGUE KSAW UNDER COOL UPSLOPE FLOW. CLOUD AREA HAS BEEN
SHRINKING PER VIS SATELLITE IMAGERY...BUT RECENT TRENDS NOW SHOW
LITTLE CHANGE. NOT OUT OF THE QUESTION THAT MVFR CIGS COULD PERSIST
RIGHT THRU THE EVENING WITH LOSS OF DAYTIME HEATING. AS WINDS VEER
TOWARD THE SE OVERNIGHT...CONTINUED LIGHT UPSLOPE FLOW MAY ALLOW
MVFR CIGS TO LINGER OR EVEN LOWER TO IFR. OTHERWISE...ATTENTION
TURNS TO FIRST APPROACHING DISTURBANCE. SHRA IN NW WI ARE HOLDING
TOGETHER AND SHOULD REACH KIWD AROUND 02Z...LEADING TO MVFR
CONDITIONS. AFTER AN HR OR TWO OF PCPN...THERE SHOULD BE A BREAK
BEFORE MORE PCPN/MVFR CONDITIONS DEVELOP LATE IN THE NIGHT.
CONDITIONS COULD FALL TO IFR. AT KCMX...VFR CONDITIONS SHOULD FALL
TO MVFR LATE IN THE NIGHT AS SHRA SPREAD ACROSS THE AREA. ALL
TERMINALS SHOULD GENERALLY BE MVFR FOR MOST OF THE DAY MON WITH SHRA
SCATTERED AROUND THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT SUN AUG 17 2014
EXCEPT FOR A BRIEF PERIOD OVER EASTERN LAKE SUPERIOR LATE MON NIGHT
INTO TUE WHEN WINDS MAY REACH 20-25 KTS UNDER A SHARPER PRES
GRADIENT BETWEEN HI PRES IN QUEBEC AND A LO TRACKING THRU THE UPPER
MIDWEST...EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A
RELATIVELY WEAK PRES GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE
THE CHILLY WATERS OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 PM EDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 407 PM EDT SAT AUG 16 2014
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER
QUEBEC WITH NW FLOW IN ITS WAKE THROUGH THE NRN GREAT LAKES.
AT THE SFC...THE COLD FRONT HAS DROPPED SOUTH OF UPPER MI AS HIGH
PRES OVER NRN MANITOBA INTO NW ONTARIO BUILDS SOUTHWARD. ALTHOUGH
STRONG MID LEVEL DRYING HAD TAKEN OVER IN THE WAKE OF THE SHRTWV
THAT MOVED THROUGH EARLY TODAY...ABUNDANT LOW LEVEL MOISTURE AND
NRLY FLOW SUSTAINED OVC SKIES OVER MOST OF NRN UPPER MI. DOWNSLOPE
FLOW AND DAYTIME MIXING HAS BROUGHT MORE CLEARING TO SRN UPPER MI.
TONIGHT...HIGH PRES WILL BUILD FROM NRN ONTARIO THROUGH THE NRN
GREAT LAKES. CLOUDS SHOULD CONTINUE TO DIMINISH THIS EVENING BUT
WILL BE BE DELAYED WHERE ONSHORE/UPSLOPE NE WINDS PREVAIL...PER
UPSTREAM/SATELLITE TRENDS AND NAM/RUC 925-900 MB RH FCST. WITH
ENOUGH CLEARING MIN READINGS WILL FALL INTO THE MID 40S INLAND BUT
WHERE THICKER CLOUDS PERSIST...LOWS WILL ONLY DROP INTO THE LOWER
50S.
SUNDAY...AS THE RIDGE BUILDS OVER THE AREA...EXPECT THAT THE
COMBINATION OF DRY ADVECTION AND MIXING BY AFTERNOON WILL FINALLY
SCOUR OUT THE REMAINING OVERCAST WITH MAINLY JUST SCT/BKN CU INLAND.
TEMPS WILL CLIMB BACK INTO EH UPPER 50S AND LOWER 70S BUT REMAIN IN
THE LOWER 60S WHERE ENE ONSHORE FLOW PREVAILS NEAR LAKE SUPERIOR.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 335 PM EDT SAT AUG 16 2014
MAIN FCST CONCERNS IN THE LONGER TERM WL FOCUS ON HOW QUICKLY SHRTWV
NOW TRACKING THRU THE NRN ROCKIES AND ACCOMPANYING DEEPER MSTR WL
ARRIVE AND IMPACT POPS INTO MID WEEK UNDER BLDG UPR RDG.
SUN NGT/MON...SFC HI PRES JUST S OF JAMES BAY UNDER RDG AXIS ACRS NW
ONTARIO AT 12Z MON WL DOMINATE AND BRING DRY WX THRU AT LEAST MOST
OF SUN NGT. BUT A GOOD NUMBER OF THE MORE RECENT MODELS HAVE TRENDED
FASTER ON SHIFTING THE REMNANT OF THE CLOSED LO TRACKING THRU THE
NRN ROCKIES/ASSOCIATED MSTR UNDER WAD IN ADVANCE OF THIS DISTURBANCE
TO THE E AND TOWARD THE UPR LKS ON MON. SO HAVE INCREASED CLD COVER
AND BROUGHT POPS TO THE E FASTER THAN SHOWN ON THE PREVIOUS FCST...
WITH CHC POPS OVER THE W BY 12Z MON AND ACROSS ALL BUT THE E ON MON
AFTN AS PWAT IS FCST TO INCRS TO 1.50 TO 1.75 INCHES UNDER FALLING
HGTS/DIFFLUENT UPR FLOW/DPVA/DEEP LYR QVECTOR CNVGC TO THE E OF THE
APRCHG SHRTWV. CONSIDERING THE FASTER ARRIVAL OF THE MSTR/STRONGER
SLY FLOW FM THE W...BUMPED UP FCST MIN TEMPS OVER THE W ON SUN NGT.
BUT LOWERED FCST TEMPS OVER THE INTERIOR E CLOSER TO THE DEPARTING
SFC HI/DRIER AIR WITH PWAT UNDER 0.75 INCH/LIGHTER WINDS. WITH AN
EARLIER ARRIVAL OF MORE CLDS ON MON...OPTED TO LOWER FCST HI TEMPS A
BIT DESPITE FCST H85 TEMPS UP TO 14-15C OVER THE W.
MON NGT INTO WED...WHILE MEAN UPR RDG IS FCST TO BUILD ACROSS ERN
NAMERICA DOWNSTREAM OF DEEPENING TROF OVER THE W...SHRTWV APRCHG FM
THE W WL DRIFT SLOWLY THRU THE GREAT LKS. UNDER POCKET OF COOLER H5
TEMPS/HIER PWAT UP TO 1.50-1.75 INCHES...THERE WL BE AT LEAST SOME
SCT SHOWERS/A FEW TS ARND DURING THIS PERIOD. THE PROBABILITY OF
THESE SHOWERS WL BE GREATEST DURING DAYTIME HEATING ON TUE AFTN/
EVNG. A GOOD DEAL OF CLD COVER WL RESTRICT THE DIURNAL TEMP
RANGE...WITH HI TEMPS NOT FAR FM 70 RUNNING BLO NORMAL BUT MRNG LO
TEMPS MAINLY 55 TO 60 ABV AVG. IF THE UPR LO EXITS FASTER ON WED...
MORE AFTN SUNSHINE MIGHT ALLOW FOR WARMER TEMPS THEN.
END OF THE WEEK...AS THE SHRTWV MOVING THRU THE LKS SHIFTS AWAY
LATER WED AND HGTS RISE...EXPECT A DRYING TREND FOR WED NGT INTO
THU. SOME OF THE LONGER RANGE GUIDANCE HINTS ANOTHER SHRTWV RIDING
ENEWD THRU THE UPR MS RIVER VALLEY AND TOWARD NW ONTARIO/THE UPR LKS
MAY BRING MORE SHOWERS/A FEW TS TO THE AREA LATER ON THU INTO FRI.
VARIOUS MODELS INDICATE THIS SHRTWV WL BE SLOWER AND NOT IMPACT THE
AREA UNTIL SAT. CONSIDERING THE UNCERTAINTY ON SPECIFICS THIS FAR
OUT IN THE FCST PERIOD...WL RELY ON EXTENDED MODEL CONSENSUS FOR
FCST GENERATION. OVERALL TEMPS SHOULD RUN AOA NORMAL IN THE PRESENCE
OF MEAN UPR RDG TO THE E OF LARGER SCALE WRN TROF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 139 PM EDT SAT AUG 16 2014
LOW CLOUDS WITH IFR/MVFR CIGS AT SAW/CMX ARE EXPECTED TO GIVE WAY TO
SOME IMPROVEMENT BY LATE AFTERNOON AS DAYTIME MIXING AND WEAK DRY
ADVECTION STRENGTHEN. HOWEVER...PERSISTENT MOIST UPSLOPE FLOW AT SAW
WILL DELAY ANY CLEARING UNTIL LATER THIS EVENING. THE VFR CONDITIONS
AT SAW MAY BE BRIEF AS CONTINUED MOIST NE FLOW STRENGTHENS LEADING TO
MVFR CONDITIONS. THE NE OR ENE FLOW WILL BE LESS FAVORABLE FOR LOWER
CLOUDS AT CMX OR IWD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 335 PM EDT SAT AUG 16 2014
EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A RELATIVELY WEAK
PRESSURE GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY
WATERS OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...JLB
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
755 AM EDT SAT AUG 16 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 323 AM EDT SAT AUG 16 2014
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY WITH THE
GREATEST LIKELIHOOD ACROSS CENTRAL LOWER MI THIS AFTERNOON WITH LESS
COVERAGE ANTICIPATED ACROSS SOUTHERN LOWER MI THIS EVENING AND
TONIGHT. MOST OF SUNDAY AND MONDAY WILL BE DRY ALTHOUGH A FEW
SHOWERS MAY POP UP BOTH DAYS MAINLY SOUTH OF A GRAND RAPIDS TO
LANSING LINE. TUESDAY THROUGH FRIDAY LOOKS WARM AND UNSETTLED AT
TIMES WITH OPPORTUNITIES FOR MORE SHOWERS AND STORMS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014
NOT MUCH HAS CHANGED WITH PREVIOUS THINKING REGARDING CONVECTIVE
EVOLUTION TODAY THROUGH SUNDAY. THE MAIN THEME WILL BE MORE NUMEROUS
SHOWERS AND THUNDERSTORMS ACROSS CENTRAL LOWER MI DURING THE
AFTERNOON HOURS WITH A MORE NARROW LINE OF SCATTERED SHOWERS/STORMS
MOVING THROUGH SOUTHERN LOWER FOR THE EVENING AND LATE NIGHT HOURS.
THE SEVERE WEATHER THREAT LOOKS QUITE LOW OVERALL.
HI RES MODELS INCLUDING THE NSSL WRF AND HRRR INDICATE THE BROKEN
LINE OF SHOWERS/STORMS CURRENTLY OVER NORTHERN WI / U.P. AREA WILL
MOVE SOUTHEAST AND BE MOST WIDESPREAD ACROSS NORTHERN AND CENTRAL
LOWER MI THIS AFTERNOON WHERE H500 HEIGHTS ARE LOWEST AND SFC CONV
AS WELL AS LOW LEVEL MOISTURE FLUX CONV WILL BE MAXIMIZED. HI RES
RADAR REF SIM SUGGESTS THE CONVECTIVE EVOLUTION WILL BE A
NARROW...HORIZONTALLY DRAPED LINE OF SCATTERED SHOWERS AND A FEW
STORMS THAT MOVES FROM ROUTE 10 TO I-96 BETWEEN 18Z AND 00Z...THEN
FROM I-96 TO I-94 FROM 00Z TO 06Z.
NAM BUFKIT SOUNDINGS HAVE TRENDED VERY MUCH TOWARD GFS SOUNDINGS IN
KEEPING INSTABILITY QUITE LOW FOR ALMOST THE ENTIRE CWA...EXCEPT FOR
OUR FAR NE PORTION INCLUDING MT PLEASANT AND CLARE. THIS REGION HAS
THE BEST OPPORTUNITY FOR THUNDERSTORMS DURING THE AFTERNOON HOURS.
HOWEVER...MID LEVEL LAPSE RATES CONTINUE TO MITIGATE ANY SUBSTANTIAL
HAIL THREAT AND SFC BASED CAPE MAY ONLY BE A FEW HUNDRED J/KG...SO
EQUILIBRIUM LEVELS MAY NOT BE VERY IMPRESSIVE AND A SEVERE WEATHER
THREAT LOOKS TO BE HELD DOWN CONSIDERABLY. SO...WE`LL CONTINUE TO
WATCH FOR SOME GUSTY WINDS IN THE STRONGER STORMS BUT OVERALL THIS
EVENT LOOKS MARGINAL.
SUNDAY LOOKS DRY FOR MOST AREAS SAVE NEAR AND SOUTH OF I-94 WERE
A FEW SHOWERS MAY DEVELOP IN THE MIDST OF A H850 THERMAL AND
MOISTURE GRADIENT AND WEAK EASTERLY SFC CONV. EVEN INTO
MONDAY...WITH THE H850 THERMAL GRADIENT STILL IN PLACE AND A WEAK
H500 SHORTWAVE MOVING THROUGH DURING PEAK HEATING...SOME ISOLATED
SHOWERS MAY DEVELOP. THIS WOULD PRIMARILY BE FOR AREAS SOUTH OF A
GRR TO LAN LINE. NONE OF THIS ACTIVITY ON SUNDAY OR MONDAY LOOKS
WIDESPREAD OR SIGNIFICANT. HAVE REMOVED ALL MENTION OF THUNDER FOR
BOTH OF THESE DAYS AS MODEL SOUNDINGS DO NOT SUPPORT IT.
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014
HIGH CONFIDENCE IN WARM SUMMERLIKE TEMPERATURES IN THE LONG TERM
PERIOD... ALTHOUGH IT LOOKS LIKE THE HOT/HUMID/UNCOMFORTABLE AIR
WITH HIGHS AROUND 90 AND DEW POINTS NEAR 70 SHOULD REMAIN JUST TO
OUR SOUTHWEST.
EARLY NEXT WEEK WE WILL BE WATCHING A SLOW MOVING SHORTWAVE WHICH
MOVES FROM NORTHERN MINNESOTA ON MONDAY TO WISCONSIN ON TUESDAY TO
LWR MI ON WEDNESDAY. A WEAK/ILL DEFINED SFC TROUGH/WARM FRONT...
ORIENTED IN A NW-SE FASHION... ACCOMPANIES/PRECEDES THIS FEATURE AS
IT IMPACTS THE UPR MIDWEST AND GRTLKS REGION DURING THE EARLY TO MID
WEEK PERIOD.
OUR BEST CHANCE OF SHOWERS/TSTMS WOULD APPEAR TO BE ON TUESDAY AND
WEDNESDAY... PARTICULARLY IN THE AFTERNOON/EVENING HOURS WITH
DIURNAL BOOST.
ONCE THE SHORTWAVE EXITS THE REGION BY THURSDAY... HEIGHT RISES
COMMENCE. HOWEVER A CHANCE OF A FEW SHOWERS AND TSTMS WILL REMAIN
SINCE THE WARM FRONT SHOULD BE SITUATED JUST TO OUR SOUTHWEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 755 AM EDT SAT AUG 16 2014
VFR CONDITIONS ARE EXPECTED TODAY INTO THIS EVENING. THE CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS IS NOT EXPECTED TO REACH THE
TAF SITES ALONG THE I-96 CORRIDOR UNTIL AFTER 22Z... AND A COUPLE
HOURS LATER ALONG THE I-94 CORRIDOR. EVEN WITH THE SCATTERED
SHOWERS IT SHOULD REMAIN PRIMARILY VFR.
WHILE THERE IS A THUNDER THREAT LATE TODAY AND THIS EVENING... FEEL
THE PROBABILITY IS TOO LOW TO INCLUDE VCTS IN ANY OF THE TAFS AT
THIS TIME... WITH THE EXCEPTION OF LAN.
WEST-SOUTHWEST SFC WINDS OF 10 TO 20 KTS WITH SOME HIGHER GUSTS
WILL OCCUR MUCH OF TODAY... THEN DIMINISH QUICKLY AFTER 22Z AS THE
SFC COLD FRONT APPROACHES FROM THE NORTH AND THE GRADIENT RELAXES.
AFTER 06Z TONIGHT SOME LOWER CIGS/VSBYS WILL PROBABLY DEVELOP
BEHIND THE COLD FRONT. IFR CONDITIONS ARE QUITE POSSIBLE BY 12Z
SUNDAY MORNING...ESPECIALLY SOUTH AND EAST OF GRR.
&&
.MARINE...
ISSUED AT 323 AM EDT SAT AUG 16 2014
A 2 TO 3 FOOT CHOP CAN BE EXPECTED THIS MORNING AND AFTERNOON WITH
SW WINDS PICKING UP. WINDS AND WAVES DECREASE THIS EVENING AND
EASTERLY WINDS WILL KEEP MOST WAVE ACTION AWAY FROM OUR NEARSHORE
ZONES ON MONDAY.
&&
.HYDROLOGY...
ISSUED AT 323 AM EDT SAT AUG 16 2014
NO SIGNIFICANT RAINFALL IS EXPECTED OVER THE NEXT FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...HOVING
MARINE...HOVING
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
333 AM EDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 351 PM EDT FRI AUG 15 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A RIDGE FROM THE NRN PLAINS INTO
CNTRL ALBERTA AND A TROUGH OVER QUEBEC. AN UPSTREAM SHORTWAVE TROUGH
AND ASSOCIATED COLD FRONT WAS DIVING SE THROUGH NW ONTARIO. AT THE
SFC...LIGHT SW WINDS PREVAILED ACROSS UPPER MI AS HIGH PRES SINKS
INTO THE SRN LAKES.
TONIGHT INTO SAT...EXPECT SHRA/TSRA TO DEVELOP MAINLY AFT 06Z OVER
NORTHERN LAKE SUPERIOR THAT WILL SPREAD QUICKLY SE AS MODELS WERE IN
GOOD AGREEMENT IN BRINGING THE SHORTWAVE TROUGH WITH MODERATE 700-300
MB QVECTOR CONV...STRONG UPPER LEVEL DIV WITH THE LEFT EXIT OF A 90
KNOT 250-300 MB JET...AND AN ASSOCIATED COLD FRONT THROUGH THE NRN
GREAT LAKES. MODELS SHRTWV FORCING SUGGEST THAT THE ERN CWA WILL SEE
THE GREATEST PCPN COVERAGE/QPF WITH LIKELY TO CATEGORICAL POPS. GIVEN
POTENTIAL OF MUCAPE TO NEAR 800 J/KG... MODERATE TO STRONG DYNAMICS
AND EFFECTIVE SHEAR TO 40 KNOTS SOME EVEN MAINLY ELEVATED STORMS
ABOVE THE SHALLOW BNDRY LAYER MAY BE STRONG CAPABLE OF PRODUCING SOME
GUSTY WINDS AND SMALL HAIL. BY SAT AFTERNOON IN THE WAKE OF THE
FRONT...PCPN CHANCES SHOULD DIMINISH ACROSS THE NORTH WITH COOLER
MORE STABLE AIR MOVING IN ON LOW LEVEL NRLY FLOW. SOME DRIZZLE MAY
LINGER IN THE HIGHER TERRAIN N CNTRL IN THE MORNING IN THE WAKE OF
ANY SHOWERS EARLIER IN THE MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 333 AM EDT SAT AUG 16 2014
NAM SHOWS SOME SHORTWAVE RIDGING OVER THE UPPER GREAT LAKES 12Z SUN
WITH TROUGHING MOVING INTO THE NORTHERN PLAINS ON SUN. THIS TROUGH
AFFECTS THE AREA MON INTO MON NIGHT. NAM SHOWS SOME DEEPER MOISTURE
AND 850-500 MB Q-VECTOR CONVERGENCE ARRIVING LATE MON AFTERNOON INTO
THE WESTERN CWA AND THIS OVERSPREADS THE CWA MON NIGHT. WILL HAVE
QUIET WEATHER THROUGH MON BEFORE POPS ARRIVE MON NIGHT ACROSS THE
WESTERN HALF OF THE CWA. DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST FOR TEMPERATURES AND CONTINUED THE DRY WEATHER SUN THROUGH
MON.
IN THE EXTENDED...GFS AND THE ECMWF SHOW A 500 MB TROUGH IN THE
UPPER GREAT LAKES REGION 12Z TUE WHICH REMAINS STATIONARY INTO
WED...THEN THIS TROUGH HEADS NORTHWARD 12Z THU AS IT ENCOUNTERS A
RIDGE ACROSS EASTERN CANADA. WHAT THIS WILL MEAN IS THE WEATHER WILL
REMAIN UNSETTLED WITH SFC FRONTS NEAR THE AREA AND TEMPERATURES WILL
BE ABOVE NORMAL. WILL HAVE SOME POPS FOR THE WHOLE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 131 AM EDT SAT AUG 16 2014
DISTURBANCE AND ASSOCIATED COLD FRONT WILL SWEEP S ACROSS THE AREA
OVERNIGHT/EARLY THIS MORNING. INITIALLY...CONDITIONS WILL BE VFR AT
KWID/KCMX/KSAW. SHRA/ISOLD TSRA ALONG COLD FRONT WILL BE MORE LIKELY
TO AFFECT KCMX/KSAW THAN KIWD. WITH THUNDER LIKELY TO CONTINUE
DIMINISHING ALONG COLD FRONT...RETAINED ONLY A MENTION OF -SHRA
IN FCST. BEHIND FRONT...A PERIOD OF IFR CIGS IS LIKELY AT ALL
TERMINALS THIS MORNING UNDER MOIST UPSLOPE FLOW...ESPECIALLY AT KSAW
DUE TO UPSLOPE FLOW OFF THE COLDER ERN PORTION OF LAKE SUPERIOR.
IMPROVEMENT TO VFR SHOULD OCCUR AT KIWD/KCMX EARLY AFTN WHILE KSAW
MAY ONLY IMPROVE TO MVFR. VFR CONDITIONS SHOULD RETURN TO KSAW EARLY
THIS EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EDT FRI AUG 15 2014
EXPECT WINDS UNDER 20 KTS THRU NEXT WED AS A RELATIVELY WEAK PRES
GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF
LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...07
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
330 AM EDT SAT AUG 16 2014
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 323 AM EDT SAT AUG 16 2014
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE TODAY WITH THE
GREATEST LIKELIHOOD ACROSS CENTRAL LOWER MI THIS AFTERNOON WITH LESS
COVERAGE ANTICIPATED ACROSS SOUTHERN LOWER MI THIS EVENING AND
TONIGHT. MOST OF SUNDAY AND MONDAY WILL BE DRY ALTHOUGH A FEW
SHOWERS MAY POP UP BOTH DAYS MAINLY SOUTH OF A GRAND RAPIDS TO
LANSING LINE. TUESDAY THROUGH FRIDAY LOOKS WARM AND UNSETTLED AT
TIMES WITH OPPORTUNITIES FOR MORE SHOWERS AND STORMS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014
NOT MUCH HAS CHANGED WITH PREVIOUS THINKING REGARDING CONVECTIVE
EVOLUTION TODAY THROUGH SUNDAY. THE MAIN THEME WILL BE MORE NUMEROUS
SHOWERS AND THUNDERSTORMS ACROSS CENTRAL LOWER MI DURING THE
AFTERNOON HOURS WITH A MORE NARROW LINE OF SCATTERED SHOWERS/STORMS
MOVING THROUGH SOUTHERN LOWER FOR THE EVENING AND LATE NIGHT HOURS.
THE SEVERE WEATHER THREAT LOOKS QUITE LOW OVERALL.
HI RES MODELS INCLUDING THE NSSL WRF AND HRRR INDICATE THE BROKEN
LINE OF SHOWERS/STORMS CURRENTLY OVER NORTHERN WI / U.P. AREA WILL
MOVE SOUTHEAST AND BE MOST WIDESPREAD ACROSS NORTHERN AND CENTRAL
LOWER MI THIS AFTERNOON WHERE H500 HEIGHTS ARE LOWEST AND SFC CONV
AS WELL AS LOW LEVEL MOISTURE FLUX CONV WILL BE MAXIMIZED. HI RES
RADAR REF SIM SUGGESTS THE CONVECTIVE EVOLUTION WILL BE A
NARROW...HORIZONTALLY DRAPED LINE OF SCATTERED SHOWERS AND A FEW
STORMS THAT MOVES FROM ROUTE 10 TO I-96 BETWEEN 18Z AND 00Z...THEN
FROM I-96 TO I-94 FROM 00Z TO 06Z.
NAM BUFKIT SOUNDINGS HAVE TRENDED VERY MUCH TOWARD GFS SOUNDINGS IN
KEEPING INSTABILITY QUITE LOW FOR ALMOST THE ENTIRE CWA...EXCEPT FOR
OUR FAR NE PORTION INCLUDING MT PLEASANT AND CLARE. THIS REGION HAS
THE BEST OPPORTUNITY FOR THUNDERSTORMS DURING THE AFTERNOON HOURS.
HOWEVER...MID LEVEL LAPSE RATES CONTINUE TO MITIGATE ANY SUBSTANTIAL
HAIL THREAT AND SFC BASED CAPE MAY ONLY BE A FEW HUNDRED J/KG...SO
EQUILIBRIUM LEVELS MAY NOT BE VERY IMPRESSIVE AND A SEVERE WEATHER
THREAT LOOKS TO BE HELD DOWN CONSIDERABLY. SO...WE`LL CONTINUE TO
WATCH FOR SOME GUSTY WINDS IN THE STRONGER STORMS BUT OVERALL THIS
EVENT LOOKS MARGINAL.
SUNDAY LOOKS DRY FOR MOST SAVE AREAS NEAR AND SOUTH OF I-94 WERE A
FEW SHOWERS MAY DEVELOP IN THE MIDST OF A H850 THERMAL AND MOISTURE
GRADIENT AND WEAK EASTERLY SFC CONV. EVEN INTO MONDAY...WITH THE
H850 THERMAL GRADIENT STILL IN PLACE AND A WEAK H500 SHORTWAVE
MOVING THROUGH DURING PEAK HEATING...SOME ISOLATED SHOWERS MAY
DEVELOP. THIS WOULD PRIMARILY BE FOR AREAS SOUTH OF A GRR TO LAN
LINE. NONE OF THIS ACTIVITY ON SUNDAY OR MONDAY LOOKS WIDESPREAD OR
SIGNIFICANT. HAVE REMOVED ALL MENTION OF THUNDER FOR BOTH OF THESE
DAYS AS MODEL SOUNDINGS DO NOT SUPPORT IT.
&&
.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 323 AM EDT SAT AUG 16 2014
HIGH CONFIDENCE IN WARM SUMMERLIKE TEMPERATURES IN THE LONG TERM
PERIOD... ALTHOUGH IT LOOKS LIKE THE HOT/HUMID/UNCOMFORTABLE AIR
WITH HIGHS AROUND 90 AND DEW POINTS NEAR 70 SHOULD REMAIN JUST TO
OUR SOUTHWEST.
EARLY NEXT WEEK WE WILL BE WATCHING A SLOW MOVING SHORTWAVE WHICH
MOVES FROM NORTHERN MINNESOTA ON MONDAY TO WISCONSIN ON TUESDAY TO
LWR MI ON WEDNESDAY. A WEAK/ILL DEFINED SFC TROUGH/WARM FRONT...
ORIENTED IN A NW-SE FASHION... ACCOMPANIES/PRECEDES THIS FEATURE AS
IT IMPACTS THE UPR MIDWEST AND GRTLKS REGION DURING THE EARLY TO MID
WEEK PERIOD.
OUR BEST CHANCE OF SHOWERS/TSTMS WOULD APPEAR TO BE ON TUESDAY AND
WEDNESDAY... PARTICULARLY IN THE AFTERNOON/EVENING HOURS WITH
DIURNAL BOOST.
ONCE THE SHORTWAVE EXITS THE REGION BY THURSDAY... HEIGHT RISES
COMMENCE. HOWEVER A CHANCE OF A FEW SHOWERS AND TSTMS WILL REMAIN
SINCE THE WARM FRONT SHOULD BE SITUATED JUST TO OUR SOUTHWEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1150 PM EDT FRI AUG 15 2014
VFR AND LIGHT WINDS WILL CONTINUE THROUGH DAYBREAK. WSW WINDS ARE
STILL EXPECTED TO INCREASE TO 10-15 KNOTS BETWEEN 13Z AND 16Z
AHEAD OF A WEAK COLD FRONT.
THE FRONT WILL CROSS MOST OF THE TAF SITES BETWEEN 00Z AND 06Z
SUNDAY. THE BEST DYNAMICS WITH THE FRONT REMAINS TO OUR NE...SO
EXPECT ANY STORMS WILL BE VERY WIDELY SCATTERED OR EVEN ISOLATED.
THE FURTHER WEST ONE GOES...THE BETTER LIKELIHOOD OF STAYING DRY.
THEREFORE HAVE REMOVE VICINITY THUNDER FOR MKG AND GRR AS THE ODDS
SEEM TOO LOW TO INCLUDE IN THESE TAFS AT THIS POINT. THE REMAINDER
OF THE TAF SITES MAY SEE VERY HIT OR MISS THUNDERSTORMS BETWEEN
21Z AND 06Z...BUT PROBABLY ONLY FOR A COUPLE HOURS AT ANY ONE
LOCATION. OUTSIDE OF ANY THUNDERSTORMS IT SHOULD REMAIN VFR...
HOWEVER AS THE FRONT SLOWS NEAR I-94 SOME MVFR CEILINGS COULD
DEVELOP TOWARD THE END OF THIS FORECAST PERIOD.
&&
.MARINE...
ISSUED AT 323 AM EDT SAT AUG 16 2014
A 2 TO 3 FOOT CHOP CAN BE EXPECTED THIS MORNING AND AFTERNOON WITH
SW WINDS PICKING UP. WINDS AND WAVES DECREASE THIS EVENING AND
EASTERLY WINDS WILL KEEP MOST WAVE ACTION AWAY FROM OUR NEARSHORE
ZONES ON MONDAY.
&&
.HYDROLOGY...
ISSUED AT 323 AM EDT SAT AUG 16 2014
NO SIGNIFICANT RAINFALL IS EXPECTED OVER THE NEXT FEW DAYS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...MEADE
AVIATION...JK
HYDROLOGY...HOVING
MARINE...HOVING
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
131 AM EDT SAT AUG 16 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 351 PM EDT FRI AUG 15 2014
WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW
THROUGH THE WRN GREAT LAKES BETWEEN A RIDGE FROM THE NRN PLAINS INTO
CNTRL ALBERTA AND A TROUGH OVER QUEBEC. AN UPSTREAM SHORTWAVE TROUGH
AND ASSOCIATED COLD FRONT WAS DIVING SE THROUGH NW ONTARIO. AT THE
SFC...LIGHT SW WINDS PREVAILED ACROSS UPPER MI AS HIGH PRES SINKS
INTO THE SRN LAKES.
TONIGHT INTO SAT...EXPECT SHRA/TSRA TO DEVELOP MAINLY AFT 06Z OVER
NORTHERN LAKE SUPERIOR THAT WILL SPREAD QUICKLY SE AS MODELS WERE IN
GOOD AGREEMENT IN BRINGING THE SHORTWAVE TROUGH WITH MODERATE 700-300
MB QVECTOR CONV...STRONG UPPER LEVEL DIV WITH THE LEFT EXIT OF A 90
KNOT 250-300 MB JET...AND AN ASSOCIATED COLD FRONT THROUGH THE NRN
GREAT LAKES. MODELS SHRTWV FORCING SUGGEST THAT THE ERN CWA WILL SEE
THE GREATEST PCPN COVERAGE/QPF WITH LIKELY TO CATEGORICAL POPS. GIVEN
POTENTIAL OF MUCAPE TO NEAR 800 J/KG... MODERATE TO STRONG DYNAMICS
AND EFFECTIVE SHEAR TO 40 KNOTS SOME EVEN MAINLY ELEVATED STORMS
ABOVE THE SHALLOW BNDRY LAYER MAY BE STRONG CAPABLE OF PRODUCING SOME
GUSTY WINDS AND SMALL HAIL. BY SAT AFTERNOON IN THE WAKE OF THE
FRONT...PCPN CHANCES SHOULD DIMINISH ACROSS THE NORTH WITH COOLER
MORE STABLE AIR MOVING IN ON LOW LEVEL NRLY FLOW. SOME DRIZZLE MAY
LINGER IN THE HIGHER TERRAIN N CNTRL IN THE MORNING IN THE WAKE OF
ANY SHOWERS EARLIER IN THE MORNING.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 348 PM EDT FRI AUG 15 2014
MAIN FCST CONCERNS IN THE LONG RANGE WL FOCUS ON TEMPS/PSBL LO CLDS
EARLY NEXT WEEK WITH NNE FLOW ON THE SRN FLANK OF DRY CNDN HI PRES
FCST TO DOMINATE. HOW QUICKLY A CHC OF SHOWERS WL RETURN TO THE FCST
IS THE CHALLENGE FOR THE MIDDLE OF NEXT WEEK.
SAT NGT...UNDER CONFLUENT NW FLOW ALF BTWN UPR RDG IN THE PLAINS AND
DEEP TROF IN QUEBEC...SFC HI PRES OVER FAR NW ONTARIO IS PROGGED TO
DRIFT SLOWLY SEWD TOWARD NRN LK SUP BY 12Z SUN. ANY LINGERING CLDS
EARLY OVER THE SCENTRAL ASSOCIATED WITH DEPARTING COLD FNT WL SHIFT
TO THE S AS THE HI PRES BUILDS TOWARD THE CWA UNDER LARGER SCALE
DNVA/DEEP LYR QVECTOR DVGC AND THE AIRMASS DRIES. IN FACT...
GUIDANCE INDICATES PWAT WL SINK TO ARND 0.5 INCH BY 12Z SUN...ABOUT
50 PCT OF NORMAL. THE MAJOR CONCERN IS THE POTENTIAL FOR SOME LO
CLDS TO DVLP...MAINLY IN THOSE AREAS OVER THE NCNTRL IMPACTED BY
UPSLOPE NNE WIND COMPONENT ON THE SRN FLANK OF THE APRCHG HI PRES.
IN FACT...THE 12Z NAM/REGIONAL CNDN/LOCAL WRF ARW FCST SDNGS SHOW A
SHALLOW...MOIST INFUSION OF COOLER AIR BLO SHARP SUBSIDENCE INVRN
BASED NEAR H9 ASSOCIATED WITH THE LARGER SCALE SUBSIDENCE/DRYING.
THESE FCSTS ARE BACKED UP BY SOME FAIRLY EXTENSIVE LO CLD COVER NOW
PRESENT OVER FAR NW ONTARIO ASSOCIATED WITH SHALLOW MOIST LYR
DEPICTED ON THE 12Z CHURCHILL MANITOBA RAOB. WL THUS INTRODUCE MORE
CLDS INTO THE FCST...MAINLY OVER THE NCENTRAL. THESE CLDS AND
EXPECTED STEADY NNE WIND WL LIMIT THE DIURNAL TEMP FALL A BIT
ESPECIALLY NEAR LK SUP OVER THE E HALF WHERE THE PRES GRADIENT IS
FCST TO BE A BIT TIGHTER. EXPECT THE LOWEST MIN TEMPS IN THE 40S
OVER THE INTERIOR W...CLOSER TO THE RDG AXIS EXTENDING FM THE HI
CENTER S TOWARD THE UPR MIDWEST AND WHERE WINDS WL BE LIGHTER AND
DOWNSLOPE WIND COMPONENT SHOULD LIMIT THE POTENTIAL FOR MORE
EXTENSIVE LO CLD.
SUN THRU MON...AS UPR RDG AXIS BUILDS INTO THE GREAT LKS FM THE W
FOLLOWING A SLOWLY EXITING QUEBEC TROF...SFC HI PRES IS FCST TO
DRIFT SLOWLY E AND INTO WRN QUEBEC BY MON AFTN. AM LO CLDS MAINLY
OVER THE NCENTRAL ON SUN MRNG SHOULD MIX OUT DURING THE AFTN WITH
DAYTIME HEATING AND THE ARRIVAL OF DRIER AIR. OTRW...THE WX OVER UPR
MI SHOULD REMAIN UNEVENTFUL WITH RDG AXIS EXTENDING WWD FM THE HI
CENTER INTO THE UPR LKS AND RELATIVELY DRY AIRMASS LINGERING. BOTH
SUN AND MON SHOULD FEATURE PLEASANT MAX TEMPS IN THE 70S AWAY FM LK
MODERATION AS H85 TEMPS ARE FCST TO TOP OUT BTWN 10-12C AND SUN AND
11-13C ON MON. MIN TEMPS ON SUN NGT WL DIP INTO THE 40S OVER THE
INTERIOR UNDER MOCLR SKIES/LIGHT WINDS DESPITE A SLOW INCRS IN PWAT
AOA 0.75 INCH.
EXTENDED...REMNANT OF CUTOFF UPR LO NOW MOVING EWD THRU THE PAC NW
IS FCST TO DRIFT SLOWLY E AND INTO THE UPR LKS ON TUE-THU NEXT WEEK
AT THE SAME TIME LARGER SCALE UPR RDG WL BE BUILDING OVER THE UPR
LKS DOWNSTREAM OF DEEPENING TROF OVER WRN CANADA/THE NW CONUS. FCST
WL INCLUDE SOME POPS AS THE SHRTWV/DEEPER MSTR INFLUENCE THE AREA...
BUT SLOWLY RISING H5 UNDER THE EXPANDING MEAN RDG SHOULD TEND TO
LIMIT THE SHOWER COVERAGE AND POPS TO THE CHC RANGE. WITH FCST H85
TEMPS NOT FAR FM 13-15C AND SOME CLDS...TEMPS SHOULD BE NOT FAR FM
THE MID/LATE AUG NORM. AS THE SHRTWV/DEEPER MSTR SLOWLY LIFT TO THE
NE AND H85 TEMPS WARM INTO THE 17-20C RANGE BY NEXT FRI UNDER THE
SLOWLY BLDG UPR RDG...EXPECT A RETURN OF ABV NORMAL TEMPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 131 AM EDT SAT AUG 16 2014
DISTURBANCE AND ASSOCIATED COLD FRONT WILL SWEEP S ACROSS THE AREA
OVERNIGHT/EARLY THIS MORNING. INITIALLY...CONDITIONS WILL BE VFR AT
KWID/KCMX/KSAW. SHRA/ISOLD TSRA ALONG COLD FRONT WILL BE MORE LIKELY
TO AFFECT KCMX/KSAW THAN KIWD. WITH THUNDER LIKELY TO CONTINUE
DIMINISHING ALONG COLD FRONT...RETAINED ONLY A MENTION OF -SHRA
IN FCST. BEHIND FRONT...A PERIOD OF IFR CIGS IS LIKELY AT ALL
TERMINALS THIS MORNING UNDER MOIST UPSLOPE FLOW...ESPECIALLY AT KSAW
DUE TO UPSLOPE FLOW OFF THE COLDER ERN PORTION OF LAKE SUPERIOR.
IMPROVEMENT TO VFR SHOULD OCCUR AT KIWD/KCMX EARLY AFTN WHILE KSAW
MAY ONLY IMPROVE TO MVFR. VFR CONDITIONS SHOULD RETURN TO KSAW EARLY
THIS EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EDT FRI AUG 15 2014
EXPECT WINDS UNDER 20 KTS THRU NEXT WED AS A RELATIVELY WEAK PRES
GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE THE CHILLY WATERS OF
LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
746 PM CDT SUN AUG 17 2014
.UPDATE...
FOR 00Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 142 PM CDT SUN AUG 17 2014
TWO ROUNDS OF THUNDERSTORMS EXPECTED OVER THE NEXT 24 HOURS. THE
FIRST IS THIS AFTERNOON AND THE SECOND IS EXPECTED TOMORROW
MORNING IN MN AND AFTERNOON IN WI.
A NEARLY STATIONARY BOUNDARY IS ROUGHLY BISECTING THE FORECAST
AREA THIS AFTERNOON WITH DEWPOINTS IN THE MID TO UPPER 50S IN THE
FAR NORTHERN FORECAST AREA /CENTRAL MN AND NORTHWEST WI/ AND
LOWER 70 DEWPOINTS ACROSS SOUTH. ALONG AND SOUTH OF THE FRONT
THERE IS A PRONOUNCED INSTABILITY GRADIENT WITH SBCAPE VALUES
RANGING FROM 0-3000J/KG OVER THE SPAN OF 40-60 MILES. THE
SIGNIFICANT INCREASE IN SBCAPE WAS AIDED BY A COUPLE HOURS OF
SUNSHINE THIS AFTERNOON AND MOISTURE POOLING NEAR THE FRONT. THE
SHOWERS THIS AFTERNOON ARE STARTING TO UTILIZE THE LARGE CAPE
VALUES AND ARE NOW PRODUCING A FEW LIGHTNING STRIKES. THE 1830Z
LAPS SOUNDING NOW HAS A FREEZING LEVEL OF 15KFT AND PWAT VALUES OF
1.75"...PROVIDING A GREAT ATMOSPHERE FOR WARM RAIN PROCESSES AND
HIGH RAIN RATES FOR RELATIVELY SMALL SHOWERS. WE EXPECT THESE
INTENSE-SMALL SHOWERS TO CONTINUE MOVING EAST ACROSS EASTERN
MN...WITH A SLOW DIMINISHING TREND NEAR SUNSET.
WE INCREASED POPS AND KEPT THE MENTION OF HEAVY RAIN IN THE
FORECAST TOMORROW FROM 09-21Z...WITH THE EXPECTATION OF ANOTHER
COMPLEX OF THUNDERSTORMS EXPECTED TO MOVE OUT OF SOUTH DAKOTA AND
INTO WESTERN MN BEFORE SUNRISE. WE USED A BLEND OF THE 17.12Z GEM-
REG AND NEW AND IMPROVED 17.12Z NAM...WHICH ARE IN VERY GOOD
AGREEMENT WITH ONE ANOTHER. EARLY LOOK AT SOME THE CAM GUIDANCE
FOR TOMORROW IS ALSO TRENDING THIS WAY. THE UPPER LOW WEST OF LAKE
WINNIPEG AND TRAILING TROUGH AND STRONG PV ADVECTION SHOULD BE THE
FOCUS FOR THIS COMPLEX LATE TONIGHT AND TOMORROW. HARD TO IMAGINE THIS
SECOND COMPLEX MISSING THE FORECAST TOMORROW GIVEN HOW CLOSE WE
ARE NOW.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 PM CDT SUN AUG 17 2014
THE BACK EDGE OF THE AFOREMENTIONED COMPLEX WILL BE HEADED EAST
ACROSS ERN MN AND WRN WI AT THE BEGINNING OF THE PERIOD...WITH THE
POSSIBILITY OF RESIDUAL SHOWERS CONTINUING THROUGH MUCH OF THE
NIGHT...ESPECIALLY OVER WI. KEPT POPS IN THE CATEGORICAL RANGE
DURING THE EVENING WITH A GRADUAL TAPERING OVERNIGHT AS THE BEST
CHANCES SHIFT EAST. THE TROUGH WILL BECOME MORE NEGATIVELY TILTED
TUESDAY OVER THE WESTERN GREAT LAKES. DIURNAL SHOWER DEVELOPMENT
APPEARS LIKELY WITHIN A SOMEWHAT MOIST CYCLONIC FLOW EXTENDING
WEST INTO MN AND NORTHEASTERN IA.
SKIES WILL CLEAR TUESDAY NIGHT WITH THE SURFACE RIDGE AXIS ALIGNED
OVER THE EASTERN CWA. EXPECTING AREAS OR WIDESPREAD FOG TO DEVELOP
FROM CENTRAL TO SERN MN EASTWARD INTO WI. THERE MAY BE ENOUGH
RETURN FLOW DEVELOPING LATE TO PRECLUDE FOG FROM BECOMING AS
WIDESPREAD ACROSS SRN AND WRN MN.
MID LEVEL RIDGING WILL BUILD NORTHEASTWARD INTO THE MID MISSOURI
VALLEY DURING THE MIDDLE OF THE WEEK. IT WON/T QUITE REACH THE
CWA...SO THIS REGION OF THE COUNTRY IS LIKELY TO REMAIN UNSETTLED
THROUGHOUT MUCH OF THIS WEEK. THE FIRST WAVE TO RIDE NORTH OF THE
RIDGE WILL ARRIVE LATE WEDNESDAY THRU THURSDAY MORNING. INTRODUCED
LIKELY POPS ACROSS SRN MN WEDNESDAY NIGHT WHERE THE BEST JUXTAPOSITION
OF FORCING AND INSTABILITY WILL RESIDE. THE RESULTANT MCS WILL
DEVELOP OVER SODAK WEDNESDAY AFTERNOON AND TRACK EASTWARD INTO WI
BY MIDDAY THURSDAY.
THE RIDGE WILL RETREAT SOME FRIDAY AS A TROUGH BEGIN TO EJECT
EASTWARD FROM THE PACIFIC NORTHWEST. THE SOUTHWEST FLOW WILL SEND
ANOTHER WAVE INTO THE REGION FRIDAY AND SATURDAY WHEN POPS RETURN
INTO THE HIGH CHC RANGE.
BEYOND SATURDAY...MODELS DIVERGE SIGNIFICANTLY FROM EACH OTHER
AND FROM RUN TO RUN. YESTERDAY THEY SHOWED A STOUT HEAT WAVE OVER
THE MID/UPPER MISSISSIPPI VALLEY AND TODAY THEY SHOW A TROUGH WITH
SUB 560DM HEIGHTS. IF THE REST OF THE SUMMER IS ANY GUIDE...I
WOULD FAVOR THE LATTER SOLUTION FOR NOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 747 PM CDT SUN AUG 17 2014
IN THE WAKE OF THE FIRST WAVE OF SHOWERS AND
THUNDERSTORMS...EXPECT A BRIEF RESPITE TO ENSUE BEFORE THE NEXT
ROUND ARRIVES OVERNIGHT. PREFER THE RAP 0.5KM AGL CONDENSATIONAL
PRESSURE DEFICITS AS A GUIDE FOR CIGS IN THE NEAR-TERM. THINK IFR
CIGS WILL PLAGUE ALL BUT KRWF THIS EVE...WITH ALL SITES
EXPERIENCING MVFR CIGS AT A MINIMUM THROUGH MOST OF THE PERIOD.
OCCASIONAL SHOWERS/TS AS THE TROUGH PASSES ACROSS
TOMORROW. HARD TO TIME FOR A PARTICULAR SITE AT THIS POINT.
EAST/SOUTHEAST WINDS AHEAD OF THE WARM FRONT...THEN SHIFT TO
WEST/SOUTHWEST FOR TOMORROW. SPEEDS AROUND OR BELOW 10 KTS THROUGH
THE PERIOD.
KMSP...
CIGS ARE LOOKING MORE AND MORE PESSIMISTIC FOR THE OVERNIGHT
HOURS. PROBABILITIES ARE INCREASING THAT AT LEAST A BKN IFR LEVEL
CIG WILL PERSIST THROUGH THE OVERNIGHT HOURS...THEN LOW-END MVFR
CIGS ON MONDAY. AFTER SHRA/TS ENDS BY 03Z...SHOULD BE A BREAK IN
PRECIP UNTIL MONDAY MORNING. THEN SCATTERED SHRA/TS THROUGHOUT THE
DAY. WIND SPEEDS STAY AOB 10 KTS THROUGH THE PERIOD BUT SHIFT FROM
EAST/SOUTHEAST TO SOUTHWEST ON MONDAY MORNING.
/OUTLOOK FOR KMSP/
TUE...VFR. CHC MVFR WITH AFTERNOON TSRA. WINDS NW 5-10 KTS.
WED...VFR. WIND VRB AT 5KTS.
THU...VFR. CHC MVFR WITH TSRA. WINDS SSE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1032 PM MDT FRI AUG 15 2014
.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
10:30PM EVENING UPDATE...
WITH CONVECTION MOVING ACROSS THE CWA AND SUSTAINING ITSELF WELL
PAST DARK... IT APPEARS THERE IS MORE INSTABILITY AND EXCESS MOISTURE
TO CHEW THROUGH THAN SSEO MEMBERS ORIGINALLY HINTED AT. WITH AREAS
ACROSS THE YELLOWSTONE VALLEY HAVING RECEIVED UPWARDS OF 4 INCHES
OF STORM TOTAL RAINFALL OVER THE LAST 24 TO 48 HOURS. SOILS HAVE
BECOME SATURATED/NEAR SATURATED AND WILL HAVE DIFFICULTY
ABSORBING ANY NEW RAINFALL. INCREASED RAINFALL RATES OF 1 TO 2
INCHES FROM THE INCOMING SQUALL LINE EVIDENT ON RADAR COULD EASILY
OVERPOWER FLASH FLOOD GUIDANCE WITH BRIEF BURSTS FROM HEAVIER CELLS.
WITH BOTH WPC/HPC AND NESDIS DISCUSSIONS EXPLAINING FAVORABLE
CONDITIONS FOR SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS THE
YELLOWSTONE VALLEY... HAVE DECIDE TO PUT A FLASH FLOOD WATCH OUT
FOR THE WIBAUX... DAWSON... RICHLAND... AND PRAIRIE COUNTIES. GAH
7PM EVENING UPDATE...
LINE OF THUNDERSTORMS TO THE WEST OF THE CWA ON RADAR ARE
EXPECTED TO MOVE THROUGH THE WESTERN HALF OF THE CWA BEFORE
MIDNIGHT. AREA IS STABILIZED OUT FROM AFTERNOON CONVECTION. SO, THE
OVERALL TREND FOR ENTERING THUNDERSTORMS SHOULD BE DOWNWARD
THROUGH MIDNIGHT. POPS WERE UPDATE TO ACCOUNT FOR THIS.
PATCHY FOG IS ALSO BEING HINTED AT BY THE RAP AND HRRR. NAMDNG5
DOES NOT INCLUDE THE POSSIBILITY OF FOG AND WITH SKY COVER HAVING
A HARD TIME CLEARING CONFIDENCE IS LOW AND FOG WILL BE LIMITED IN
COVERAGE. GAH
PREVIOUS SHORT TERM DISCUSSION...
MAIN CHALLENGES THIS PERIOD WAS IF AND HOW MUCH RAIN...AND IF IT
WILL FOG TONIGHT.
TWO SYSTEMS AFFECTING THE CWA. ONE IS A MCS-TYPE DISSIPATING OVER
THE SE ZONES. GFS DOING A HORRIBLE JOB OF THIS ONE TODAY AS IT/S
QPF/S WERE TOO LOW. NAM A BIT BETTER. WITH STEADY RAIN
CONTINUING...SMALL STREAM FLOOD ADVISORY FOR THIS AREA WAS EXTENDED
TILL 630 PM.
ATTENTION THEN TURNS TO THE SECOND SYSTEM...UPPER CLOSED LOW THAT IS
DRIFTING NE INTO THE NORTHERN/CANADIAN ROCKIES. THUNDERSTORMS...SOME
SEVERE...OVER WESTERN MONTANA HAVE FORMED AS A RESULT AND ARE
EXPECTED TO SPREAD INTO CENTRAL MONTANA THIS AFTERNOON. THESE STORMS
SHOULD REACH THE WESTERN ZONES AND COULD BE STRONG.
SINCE GFS DIDN/T PERFORM WELL TODAY...SIDED MORE WITH A NAM/ECMWF
BLEND WITH THINGS THROUGH MOST OF THE PERIOD. 12Z ECMWF SHOWS DECENT
QPF FOR THE SE ZONES THAT WILL HAVE TO BE WATCHED AS SOIL CONDITIONS
ARE NOW VERY WET. OTHERWISE...SHOWERS/THUNDERSTORMS WILL CONTINUE TO
BE SCATTERED ACROSS THE CWA THROUGH THE PERIOD...PROVIDING
BENEFICIAL RAINS TO MOST AREAS. TFJ
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
FOUND BEST CONSENSUS FOR UPDATING THE LONG TERM FORECAST THROUGH
WEDNESDAY MORNING. MAIN CONCERN FOR THIS FORECAST PERIOD IS THE
INFLUENCE OF THE LARGE-SCALE UPPER-LEVEL OPEN TROUGH WHICH
DESCENDS SOUTHWARD FROM THE CANADIAN ROCKIES AND SPREADS ACROSS
OUR BORDER WITH THEM THROUGH MOST OF NEXT WEEK. THE SMALLER-SCALE
DETAILS OF SHORT WAVE ENERGY AND TIMING AND PLACEMENT STILL NEED
TO BE WORKED OUT...BUT SOME POTENTIAL EXISTS FOR MORE WIDESPREAD
AND HEAVY RAINFALL...ESPECIALLY TOWARD THE LATTER PART OF NEXT
WEEK.
LATE MONDAY THROUGH EARLY WEDNESDAY SEEMS TO BE A RELATIVELY DRY
PERIOD OF TIME BETWEEN STORM SYSTEMS. THIS WOULD COINCIDE WITH THE
GOOD MODEL CONSENSUS REPRESENTING A SHORT WAVE RIDGE DURING THIS
TIME FRAME. BMICKELSON
PREVIOUS LONG TERM DISCUSSION...UPPER TROUGH/LOW WILL EXIT THE
AREA SUNDAY NIGHT. AS THE TROUGH MOVES TO THE EAST...A SLIGHT
CHANCE OF SHOWERS AND THUNDERSTORMS WILL LINGER IN SOME AREAS IN
SOME AREAS AS WEAK WAVES ARE POSSIBLE IN THE NW FLOW ALOFT BEHIND
THE TROUGH.
MONDAY NIGHT INTO TUESDAY MORNING WILL BE MAINLY DRY WITH THE AREA
BETWEEN SYSTEMS. AN UPPER TROUGH DIGS INTO WESTERN CANADA AND THE
PACIFIC NORTHWEST ON TUESDAY AND WEDNESDAY. THIS WILL BRING
FREQUENT SHORTWAVES WITH INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS.
THE TROUGH EXPANDS INTO MONTANA ON THURSDAY AND FRIDAY WITH DEEP
MOISTURE EXPECTED. LOOK FOR A GOOD CHANCE OF SHOWERS AND
THUNDERSTORMS. FORRESTER
&&
.AVIATION...
FLIGHT CATEGORY: MAINLY VFR EXPECTED... AS LOW AS ISOLATED IFR
POSSIBLE.
SYNOPSIS: A LARGE-SCALE STORM SYSTEM WILL SLOWLY MOVE THROUGH THE
REGION OVER THE NEXT FEW DAYS. PERIODS OF RAIN SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE. HEAVY RAIN AND IFR CONDITIONS WILL
ACCOMPANY SOME OF THE STRONGER STORMS. EXPECT MAINLY MID-LEVEL SCT CLOUDS
IN BETWEEN THE SHOWERS.
FOG: DUE TO EXCESSIVE RAINFALL... LIMITED PATCHY FOG WILL BE
POSSIBLE THROUGH THE MORNING HOURS WITH ANY CLEARING THAT OCCURS
OVERNIGHT. LOCAL RAP AND HRRR MODELS ARE HINTING AT IFR
VISIBILITIES HOWEVER NAM IS NOT SO CONFIDENCE IS TOO LOW TO
INCLUDE DIRECTLY IN TAFS YET.
AREA WINDS: VARIABLE WINDS AS OUTFLOWS FROM NEARBY STORMS WILL
IMPACT WIND SPEED AND DIRECTION.
GAH/BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH SATURDAY MORNING FOR DAWSON...
PRAIRIE...RICHLAND...WIBAUX.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
645 PM CDT SUN AUG 17 2014
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT SUN AUG 17 2014
...OUR PATTERN REMAINS UNSETTLED...AND WARMER THIS WEEK...
FORECAST CHALLENGES FOR THE SHORT TERM WILL BE THUNDERSTORM
CHANCES AND SEVERE POTENTIAL TONIGHT THROUGH MONDAY EARLY
AFTERNOON.
IT LOOKED FAIRLY QUIET WEATHER TO BEGIN THIS EVENING...HOWEVER IT
SEEMS LIKE THE SHORT RANGE MODELS ARE A BIT UNDERDONE WITH THE
CONVECTION OVER CENTRAL SOUTH DAKOTA BASES ON THE LATEST RADAR.
THE HRRR HAS A SHORTWAVE AND CONVECTION THAT DROPS SOUTHEAST
ACROSS THE FORECAST AREA. THIS EVENING...WHILE THE OTHER MODELS
ARE SLOWER AND LESS AGGRESSIVE UNTIL LATER TONIGHT. EVEN THE 18Z
NAM IS STILL DRY THIS EVENING. NOT SURE HOW HIGH TO GO EARLY...BUT
WILL INCLUDE ISOLATED THUNDERSTORMS FOR PARTS OF NORTHEAST
NEBRASKA EARLY THIS EVENING. THE STORM PREDICTION CENTER DOES HAVE
A SEVERE THUNDERSTORM WATCH OUT FOR COUNTIES JUST TO THE WEST OF
OUR FORECAST AREA THIS EVENING AND THE SLIGHT RISK FOR SEVERE
WEATHER DOES CLIP OUR WESTERN FORECAST AREA COUNTIES.
THE 12Z UPPER AIR MAPS SHOWED A RIDGE OVER THE SOUTHWEST U.S. WITH A
CLOSED LOW OVER SASKATCHEWAN AND LEADING SHORTWAVE TROF ENERGY OVER
MINNESOTA. THE STRONGER HEIGHT FALLS AT H5 WERE NOTED OVER
CANADA...ASSOCIATED WITH THIS NORTHERN SYSTEM. THERE WERE RIBBONS
OF POOLED H7 MOISTURE OVER THE PLAINS WITH THE H7 THERMAL RIDGE OVER
WESTERN NEBRASKA AND COLORADO. SIMILAR PATTERNS WERE NOTED AT H85.
THE OAX SOUNDING HAD A PWAT OF 1.44 INCHES WHICH WAS 134% OF NORMAL.
A MAX OF 185% OF NORMAL WAS CENTERED OVER KMPX.
AS THE EVENING PROGRESSES...A LOW LEVEL JET INCREASES TO 35-40KTS
OVER CENTRAL NEBRASKA...MEANWHILE THE SHORTWAVE TROF ENERGY OVER
CANADA EXTENDS SOUTHWARD INTO THE PLAINS. UPPER LEVEL JET
SUPPORT...OMEGA... FRONTOGENESIS AND THETA-E ADVECTION ALL
INCREASE. AS A RESULT...THE DETERMINISTIC MODELS INCREASE
CONVECTION OVER THE DAKOTAS AND THIS CONVECTION EXTENDS SOUTHWARD
INTO EASTERN NEBRASKA AND IOWA TONIGHT AND MONDAY. THERE IS A
GOOD H7 WARM AIR ADVECTION SIGNAL AND GOOD 7-8 DEG C H7 DEWPOINTS.
EXPECTED TRENDS LATER TONIGHT ARE WELL HANDLED BY THE CURRENT
FORECAST WITH INCREASING POPS INTO THE LIKELY CATEGORY AND WILL
TREND FARTHER SOUTH TO COVER POTENTIAL FOR INCREASED CONVERGENCE
CLOSER TO THE SURFACE LOW.
DEEP LAYER SHEAR IS FROM 30- 40KTS TONIGHT...HOWEVER DROPS CLOSER
TO 30KTS MONDAY. THE SURFACE AND H85 FRONT ARE STILL IN EASTERN
NEBRASKA MONDAY MORNING...AND GRADUALLY PUSH OUT OF THE FORECAST
AREA BY 00Z MONDAY. INSTABILITY IS 500-2000J/KG TONIGHT...BUT
INCREASES TO 3000+ MONDAY. FORECAST SOUNDINGS LOOK TO FAVOR
ELEVATED STORMS TONIGHT...HOWEVER THEY ARE MORE SURFACE BASED FOR
MONDAY. ALTHOUGH FREEZING LEVELS ARE HIGHER AND INSTABILITY IS
O.K. STRONGER SHEAR...PLUME OF STEEPER LAPSE RATES AND BETTER LOW
AND MID LEVEL FORCING MAY SUPPORT SOME SEVERE STORMS. SEVERE
WEATHER CHANCES CONTINUE INTO MONDAY AS THUNDERSTORMS WILL BE
ONGOING WITH INCREASED INSTABILITY...ALTHOUGH FORCING AND SHEAR
APPEAR TO BE NOT AS HIGH. TREND WITH HIGHER POPS IN THE
AM...DECREASING FROM WEST TO EAST IN THE AFTERNOON. STORM MOTION
IS AROUND 20KTS...BUT WITH HIGH PWATS/H7 DEWPOINTS AND POTENTIAL
FOR STORMS MOVING OVER THE SAME AREA COULD PRODUCE HEAVY RAIN.
MAINLY DRY FOR MONDAY NIGHT INTO TUESDAY WITH A WARM FRONT
SITUATED OVER NORTHERN KANSAS. THERE IS LIFT OVER THE FRONT AND
THE FRONT LIFTS NORTH TUESDAY NIGHT AND WEDNESDAY...SO HAVE
SCATTERED THUNDERSTORMS MENTIONED. WARMER HIGHS IN THE 90S CAN BE
EXPECTED SOUTH OF THE FRONT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 305 PM CDT SUN AUG 17 2014
STILL QUITE A FEW MODEL DIFFERENCES WEDNESDAY NIGHT THROUGH
SUNDAY. IT LOOKS LIKE A FRONT WILL BE IN THE AREA WEDNESDAY NIGHT
THROUGH FRIDAY...WITH A MID LEVEL RIDGE TO OUR SOUTH AND A
FLATTER...TROF INFLUENCE TO OUR NORTH. WARM H85 TEMPS FROM 20-24
DEG C PERSIST THROUGH FRIDAY NIGHT...HOWEVER THE EC BRINGS COOLER
WEATHER IN FOR SATURDAY...WHILE THE GFS HOLDS OFF UNTIL SUNDAY
NIGHT.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 622 PM CDT SUN AUG 17 2014
REGIONAL RADAR THIS EVENING REVEALING SEVERAL AREAS OF CONVECTION
FROM CNTRL NEB INTO WRN/CNTRL SD PUSHING TO THE SE. GIVEN
THIS...TIMING CONVECTION AT EACH TERMINAL IS PROBLEMATIC AT BEST.
FOR KOFK...EXPECT COMPLEX DROPPING OUT OF SD WILL BE THE ONE TO
AFFECT KOFK. MODEL GUIDANCE/TIME TRAJECTORY INDICATE ACTIVITY
SHOULD BE MOVING IN AROUND 03Z THIS EVENING. AT THIS
POINT...UNSURE IF SECONDARY LINE OF TSRA CURRENTLY OVER WRN SD
WILL HOLD TOGETHER TO BE A FACTOR AT KOFK. THUS WILL NOT INCLUDE
TEMPO GROUP.
KLNK...GIVEN LATEST TRAJECTORY OF SEVERE TS CELL CURRENTLY IN
CNTRL NEB...APPEARS THAT MOVEMENT WILL TAKE IT JUST WEST OF KLNK.
HOWEVER...SEEMS TO BE AN OUTSIDE CHANCE FOR SOME TSRA ACTIVITY
EARLY MON MORNING...THUS HAVE INCLUDED PROB30 GROUP.
KOMA...AREA OBS ARE REVEALING A SUBTLE SFC BNDRY EXTENDING FROM
NERN NEB TO SRN MN. ENVIRONMENT ALONG THE MO RIVER VLY IS NOT VERY
FAVORABLE FOR INDUCING TSRA SO TSRA SHOULD NOT BE MUCH OF AN
ISSUE.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZAPOTOCNY
LONG TERM...ZAPOTOCNY
AVIATION...DEE
AREA FORECAST DISCUSSION
NWS HASTINGS NE
625 PM CDT SUN AUG 17 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 258 PM CDT SUN AUG 17 2014
THE MAIN FOCUS OF THIS FORECAST IS CENTERED AROUND A LOW-AMPLITUDE
SHORTWAVE TROUGH MAKING ITS WAY INTO THE NORTHERN/CENTRAL PLAINS.
HIGH INSTABILITY HAS DEVELOPED OVER OUR AREA AHEAD OF THIS TROUGH
WITH 3-5 J/KG CAPE INDICATED. WITH ERODING CAP AND TRENDS SHOWING
STRONGER BULK SHEAR AT 0-6KM IN THE 30 TO 35 KT RANGE THIS
EVENING...WE ARE POISED FOR SOME SEVERE WEATHER DEVELOPMENT. AN AREA
OF THUNDERSTORMS OVER NORTH CENTRAL NEBRASKA HAS ALREADY BECOME
STRONG ENOUGH TO WARN ON...WITH A CU FIELD DEVELOPING SOUTH OF
THIS INITIAL DEVELOPMENT. I EXPECT A BLOSSOMING OF THUNDERSTORMS
ALONG THE APPROACHING TROUGH THIS EVENING AND INTO THE OVERNIGHT.
WITH DECREASING INSTABILITY PAST MID-EVENING...IT MAY BE MORE
DIFFICULT TO PRODUCE SEVERE WEATHER...BUT NOT OUT OF THE QUESTION.
MODEST LOW- LEVEL JET NEAR 25 KTS WILL DEVELOP THIS EVENING THAT
COULD HELP SUSTAIN THUNDERSTORM ACTIVITY. THERE IS SOME AGREEMENT
BETWEEN THE HRRR AND WRF SOLUTIONS OF A POTENTIAL MCS TO SWING
THROUGH ROUGHLY THE NORTHERN HALF OF THE CWA. WITH EXPECTED SEVERE
PARAMETERS...WE COULD BE FAIRLY BUSY...AT LEAST FOR THE EVENING.
MOST OF THE CONVECTION SHOULD CLEAR THE CWA DURING THE OVERNIGHT
AS THE TROUGH CONTINUES EAST.
MONDAY SHOULD BE MAINLY DRY...BUT THE NAM IS INDICATING ANOTHER
PERTURBATION THAT COULD AFFECT THE SOUTHERN CWA IN KANSAS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 258 PM CDT SUN AUG 17 2014
THE LONG TERM BEGINS VERY SUMMER-LIKE AND ENDS WITH SOME POTENTIAL
FOR A MORE WIDESPREAD PRECIPITATION DEVELOPMENT BY NEXT WEEKEND.
HOWEVER...THE DETAILS ARE VERY SKETCHY BEYOND ABOUT WEDNESDAY
REGARDING TIMING/LOCATION OF PRECIPITATION TOWARD THE END OF THE
WEEK.
THE MOST INTERESTING PART OF THE UPPER LEVEL WEATHER PATTERN
WILL BE CHANGES COMING NEXT WEEKEND. MODEL GUIDANCE IN GENERAL
IS FAIRLY CONSISTENT THE CENTRAL PLAINS WILL SEE THE FLOW
TRANSITION TO AN UPPER TROUGH BY SOMETIME NEXT WEEKEND. THAT
HAS THE POTENTIAL TO BRING COOLER WEATHER AND A DECENT SHOT
FOR PRECIPITATION AT THAT TIME.
IN THE MEAN TIME...MUCH OF THE WEEK IS QUITE SUMMER-LIKE
IN TERMS OF TEMPERATURES. LOOK FOR TEMPERATURES TO BE
SLIGHTLY ABOVE NORMAL THROUGH PROBABLY THURSDAY...IF NOT
FRIDAY. NORTH CENTRAL KANSAS WILL SEE TEMPERATURES WELL
INTO THE 90S ALL WEEK. FORTUNATELY THERE WILL BE A SHORT BREAK
FROM HIGHER HUMIDITY LEVELS MONDAY NIGHT AND TUESDAY. MOISTURE
WILL START TO INCREASE AGAIN LATER IN THE WEEK AS THE UPPER
TROUGH APPROACHES AND SOUTHERLY WINDS INCREASE.
PRECIPITATION-WISE...MOST SOLD ON LATE TUESDAY NIGHT AND
EARLY WEDNESDAY WITH OVERNIGHT CONVECTION IN FACE OF STRONG
WARM ADVECTION AND 40KT LOW LEVEL JET. COVERAGE DEFINITELY
FAVORS NORTHERN AREAS...AND MAYBE EVEN NORTH OF OUR FORECAST
ALL TOGETHER. TIGHTENED UP THE PRECIPITATION CHANCES IN THE
AREA WITH THIS IN MIND. HOWEVER...AM NOT EXPECTING MORE
THAN A TENTH OR TWO OF RAIN AT MOST.
DID NOT STRAY AT ALL FROM DAYS 4-7 GUIDANCE GIVEN TO US IN THE
GRIDS...PRIMARILY BECAUSE CONFIDENCE IS NOT HIGH ENOUGH TO MAKE
SIGNIFICANT CHANGES. THE GENERAL TREND IS FOR INCREASING STORM
CHANCES BEGINNING THURSDAY NIGHT AND INTO THE WEEKEND. TEMPERATURES
COULD START TO DROP A BIT NEXT WEEKEND SHOULD PRECIPITATION
MATERIALIZE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 625 PM CDT SUN AUG 17 2014
TONIGHT: VFR EXCEPT A 2-4 HR WINDOW OF IFR TSTMS. TIMING REMAINS
UNCERTAIN...BUT THE 02Z-06Z TIME FRAME IS A START. WATCH FOR
AMENDMENTS IF TSTMS THREATEN. SE UNDER 10 KTS EXCEPT NEAR TSTMS
WHERE WIND WILL BE ERRATIC AND VARIABLE. THERE IS SOME MARGINAL
POTENTIAL FOR LLWS AFTER 06Z. CONFIDENCE: MEDIUM
MON: VFR AND ESSENTIALLY SKC. A WEAK FRONT WILL PASS THE TERMINALS
12Z-13Z WITH A WIND SHIFT TO NNW TO EVENTUALLY NNE BY
AFTERNOON. SPEEDS UNDER 10 KTS. CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...MORITZ
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
600 PM CDT SAT AUG 16 2014
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 248 PM CDT SAT AUG 16 2014
THE AREA REMAINS IN BETWEEN TWO UPPER SYSTEMS WITH ONE WELL TO OUR
NORTH AND ANOTHER TO OUR EAST. CONVECTION COULD STILL DEVELOP IN
NORTHEAST NEBRASKA ON THE FAR SOUTHERN EXTENT OF THE NORTHERN
SYSTEM...WITHIN A SLIGHTLY AGITATED CU FIELD BETWEEN KBVN...KONL
AND KYKN...AS SUGGESTED BY THE HRRR MODEL. ANY ANYTHING INDEED
DEVELOPS EARLY THIS EVENING...IT WOULD PROBABLY DIMINISH/END BY
MIDNIGHT...ALTHOUGH THE NAM WOULD HOLD IT TOGETHER ACROSS EASTERN
NEBRASKA THROUGH THE WEE HOURS.
FOCUS THEN SHIFTS TO FOG REDEVELOPMENT OVERNIGHT AS AMPLE LOW
LEVEL MOISTURE REMAINS WITH SURFACE DEWPOINTS IN THE UPPER 60S TO
LOWER 70S. WINDS WILL LIKELY GO CALM IN MANY PLACES OVERNIGHT.
MET/MAV/LAV GUIDANCE ALL INDICATES FOG WILL REDEVELOP BY 06Z...AND
COULD BECOME LOCALLY DENSE BY 09-11Z...THEN LIFTING/BURNING OFF BY
14-15Z. HAVE ADDED PATCHY DENSE FOG INTO THE GRIDS...AND MAY HAVE
TO EVENTUALLY ISSUE A DENSE FOG ADVISORY FOR PARTS OF THE REGION
TONIGHT AS CONDITIONS MATERIALIZE. AREAS MOST SUSCEPTIBLE INCLUDE
ALL OF WESTERN IOWA...THE THE PLATTE AND MISSOURI RIVER VALLEYS.
CONVECTIVE DEVELOPMENT SUNDAY IS ALSO QUESTIONABLE...BUT THE
LINGERING VERY SUBTLE TROUGH WITH ASSOCIATED ACTIVITY THIS
EVENING COULD BE ALONG THE MISSOURI RIVER SUNDAY AFTERNOON...THUS
WILL MAINTAIN JUST 20 PERCENT CHANCE OF STORMS ALONG/EAST OF THE
MISSOURI RIVER THROUGH PEAK HEATING TOMORROW.
SHOULD BE ANOTHER DRY PERIOD SUNDAY EVENING...BUT CONVECTION
CHANCES INCREASE AGAIN BY DAYBREAK MONDAY AS THE NEXT IMPULSE
BEGINS TO MOVE INTO THE AREA FROM THE HIGH PLAINS. RAIN CHANCES
CONTINUE MONDAY...AND MAY LINGER FOR SOUTHEAST NEBRASKA MONDAY
NIGHT...BUT SHOULD BE DRY AGAIN FOR TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 248 PM CDT SAT AUG 16 2014
ANOTHER SLOW MOVING WAVE MOVES INTO THE REGION TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT BRINGING ONE MORE CHANCE OF STORMS TO THE
AREA. RIDGING THEN BUILDS BACK ACROSS THE PLAINS FOR THE END OF
THE WEEK WITH DRY WEATHER...AND TEMPS WARMING INTO THE LOWER 90S
AGAIN. COULD SEE A NOCTURNAL CHANCE OF STORMS UNDERNEATH THE RIDGE
FRIDAY NIGHT.
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 600 PM CDT SAT AUG 16 2014
LOOK FOR DETERIORATING CONDITIONS OVERNIGHT WITH FOG DEVELOPING.
ISOLD TSRA COULD AFFECT KOFK FOR A FEW HOURS THIS EVENING. FOR
NOW...WE DO NOT EXPECT THIS ACTIVITY TO MAKE IT TO KOMA OR KLNK.
WINDS WILL BE LIGHT AND WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE
WE SHOULD SEE IFR CONDITIONS DEVELOP LATER TONIGHT...MAINLY AFTER
09Z. THE FOG SHOULD GRADUALLY LIFT/BREAK UP BY MID MORNING SUNDAY
LEAVING MAINLY VFR CONDITIONS FOR THE REST OF THE MORNING AND
AFTERNOON.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEWALD
LONG TERM...DEWALD
AVIATION...MILLER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
303 PM CDT SAT AUG 16 2014
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 248 PM CDT SAT AUG 16 2014
THE AREA REMAINS IN BETWEEN TWO UPPER SYSTEMS WITH ONE WELL TO OUR
NORTH AND ANOTHER TO OUR EAST. CONVECTION COULD STILL DEVELOP IN
NORTHEAST NEBRASKA ON THE FAR SOUTHERN EXTENT OF THE NORTHERN
SYSTEM...WITHIN A SLIGHTLY AGITATED CU FIELD BETWEEN KBVN...KONL
AND KYKN...AS SUGGESTED BY THE HRRR MODEL. ANY ANYTHING INDEED
DEVELOPS EARLY THIS EVENING...IT WOULD PROBABLY DIMINISH/END BY
MIDNIGHT...ALTHOUGH THE NAM WOULD HOLD IT TOGETHER ACROSS EASTERN
NEBRASKA THROUGH THE WEE HOURS.
FOCUS THEN SHIFTS TO FOG REDEVELOPMENT OVERNIGHT AS AMPLE LOW
LEVEL MOISTURE REMAINS WITH SURFACE DEWPOINTS IN THE UPPER 60S TO
LOWER 70S. WINDS WILL LIKELY GO CALM IN MANY PLACES OVERNIGHT.
MET/MAV/LAV GUIDANCE ALL INDICATES FOG WILL REDEVELOP BY 06Z...AND
COULD BECOME LOCALLY DENSE BY 09-11Z...THEN LIFTING/BURNING OFF BY
14-15Z. HAVE ADDED PATCHY DENSE FOG INTO THE GRIDS...AND MAY HAVE
TO EVENTUALLY ISSUE A DENSE FOG ADVISORY FOR PARTS OF THE REGION
TONIGHT AS CONDITIONS MATERIALIZE. AREAS MOST SUSCEPTIBLE INCLUDE
ALL OF WESTERN IOWA...THE THE PLATTE AND MISSOURI RIVER VALLEYS.
CONVECTIVE DEVELOPMENT SUNDAY IS ALSO QUESTIONABLE...BUT THE
LINGERING VERY SUBTLE TROUGH WITH ASSOCIATED ACTIVITY THIS
EVENING COULD BE ALONG THE MISSOURI RIVER SUNDAY AFTERNOON...THUS
WILL MAINTAIN JUST 20 PERCENT CHANCE OF STORMS ALONG/EAST OF THE
MISSOURI RIVER THROUGH PEAK HEATING TOMORROW.
SHOULD BE ANOTHER DRY PERIOD SUNDAY EVENING...BUT CONVECTION
CHANCES INCREASE AGAIN BY DAYBREAK MONDAY AS THE NEXT IMPULSE
BEGINS TO MOVE INTO THE AREA FROM THE HIGH PLAINS. RAIN CHANCES
CONTINUE MONDAY...AND MAY LINGER FOR SOUTHEAST NEBRASKA MONDAY
NIGHT...BUT SHOULD BE DRY AGAIN FOR TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 248 PM CDT SAT AUG 16 2014
ANOTHER SLOW MOVING WAVE MOVES INTO THE REGION TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT BRINGING ONE MORE CHANCE OF STORMS TO THE
AREA. RIDGING THEN BUILDS BACK ACROSS THE PLAINS FOR THE END OF
THE WEEK WITH DRY WEATHER...AND TEMPS WARMING INTO THE LOWER 90S
AGAIN. COULD SEE A NOCTURNAL CHANCE OF STORMS UNDERNEATH THE RIDGE
FRIDAY NIGHT.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1249 PM CDT SAT AUG 16 2014
LINGERING MOISTURE AND HEATING TO RESULT CLOUDS AND MVFR/VFR
CONDITIONS FL025-050. A FEW ISOLATED SHOWERS/STORMS MAY TRY TO
DEVELOP...ESPECIALLY TOWARD KOFK...RELATED TO A SHORTWAVE PASSING
TO THE NORTH AND LOW LEVEL CONVERGENCE. DUE TO THE ISOLATED
NATURE...WILL NOT MENTION AT THIS TIME. LATER TONIGHT...LOW LEVEL
MOISTURE REMAINS IN PLACE AND LOW LEVEL FLOW IS WEAK. FOG...DENSE
AT TIMES SHOULD RE-DEVELOP AND MENTION ESPECIALLY BETWEEN 09Z-15Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEWALD
LONG TERM...DEWALD
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
128 PM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM OFFSHORE THROUGH
EARLY NEXT WEEK WITH A TROUGH OF LOW PRESSURE INLAND. A WEAK COLD
FRONT WILL MOVE IN FROM THE NORTH TUESDAY NIGHT...THEN RETURN
NORTH WEDNESDAY.
&&
.NEAR TERM /REST OF TODAY/...
AS OF 130 PM SATURDAY...HEAVY SHOWERS AND SOME RUMBLES OF THUNDER
HAVE QUICKLY DEVELOPED ACROSS WILMINGTON`S AREA AS A SHORTWAVE GETS
HUNG UP ALONG THE SC/NC BORDER. THIS ACTIVITY COULD SHIFT
NORTHWARD WITH ADDITIONAL CONVECTION EXPECTED TO DEVELOP THIS
AFTERNOON. INCREASED TO CHC SHOWER/THUNDERSTORM ACROSS OUR SW
SECTOR TO ACCOUNT FOR THE ONGOING DEV ELOPEMENT. TEMP TRENDS LOOK
GOOD AS WE GET INTO THE UPPER 80S INLAND TO MID 80S ALONG THE
COAST. LOCATIONS TO THE SOUTH AND WEST WILL HAVE A BIT MORE CLOUD
COVER KEEPING TEMPS A DEGREE OR TWO LOWER.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...ISOLATED SHOWER/TSTM THREAT WILL CONTINUE
ACROSS NRN HALF OF AREA THROUGH 8 AM AS ADDITIONAL ACTIVITY
DEVELOPING SOUTH OF MAIN AREA NEAR NC/VA LINE. HRRR HAS GOOD
HANDLE ON THIS ACTIVITY. ISOLATED THREAT PSBL OVER NE SECTIONS 8
AM TIL NOON AND CONTINUED PREVIOUS FCST 20 POP THERE. SHRT WV
ENERGY...HEATING...INLAND TROF AND SEA BREEZE SUPPORT ISOLATED
SHOWERS/TSTMS INLAND OF COAST THIS AFTN. HIGH TEMPS AROUND 90
INLAND WITH MID 80S OBX.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...ISOLATED CONVECTIVE THREAT WILL CONTINUE
INLAND THIS EVENING...WITH ANOTHER SHRT WV MOVING IN FROM W-NW.
MODELS SUPPORT ACTIVITY DIMINISHING OVERNIGHT...BUT SOME
REDEVELOPMENT PSBL ALONG COAST NEAR MORNING...THUS NO CHANGE TO
PREVIOUS FCST. MIN TEMPS FROM AROUND 70 INLAND TO MID 70S COAST.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
AS OF 330 AM SAT...LONG TERM PERIOD WILL BE DOMINATED BY WARMING
TEMPERATURE PATTERN WITH OCCASIONAL BOUTS OF SHOWERS AND
THUNDERSTORMS.
LOW LEVEL SFC FLOW RETURNS TO THE AREA THIS WEEKEND WITH INCREASING
TEMPS...THOUGH DEWPOINTS WILL BE A BIT SLOWER TO RESPOND SO STILL
EXPECTING NEAR CLIMO LOWS OVERNIGHT. CONTINUED TYPICAL SUMMERY
PATTERN ON SUNDAY WITH ISOLATED AFTERNOON THUNDERSHOWERS ALONG SEA
BREEZE FRONT.
MED/LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH RESPECT TO
SYNOPTIC REGIME THROUGH THE LONG TERM...WITH SLOWLY BUILDING HEIGHTS
AS MID ATLANTIC RIDGE BUILDS INTO THE DEEP SOUTH. THIS WILL BRING
HOT TEMPS AND HIGH HUMIDITY VALS AS LAYER MIX RATIOS INC TO AROUND
16 G/KG EARLY TO MID NEXT WEEK. THE REGION LOOKS TO REMAIN JUST
SOUTH OF THE STORM TRACK...THOUGH COULD BE AFFECTED BY A SYSTEM
EXPECTED TO TRAVERSE THE MID ATLANTIC REGION IN THE MON NIGHT TO TUE
TIME FRAME AND THEN AGAIN MID TO LATE WEEK.
FOR MONDAY AFTERNOON AND EVENING...HAVE AN INCREASING POP TREND AS
MODEL SUITE IS IN GOOD AGREEMENT ON A COMPACT SHORTWAVE TRAVERSING
THE MID ATLANTIC STATES...WITH SFC REFLECTION NOTED ACROSS THE
DELMARVA PENINSULA MON NIGHT. TRICKY TO PIN DOWN WHERE/WHEN
DEVELOPMENT WILL TAKE PLACE IN THIS CONVECTIVE REGIME...SO HAVE
CAPPED POPS IN THE CHANCE RANGE...LOWEST ACROSS THE SOUTHERN FA.
POTENTIAL MCS ACTIVITY COULD BRING A GOOD AMOUNT OF QPF TO PARTS OF
E NC THROUGH MON NIGHT. IN ADDITION...LAYER MIX RATIOS INC QUITE A
BIT INTO THE 17 G/KG RANGE WITH PWATS AROUND 2 INCHES. THE LOW MOVES
OFFSHORE ON TUE WITH ATTENDANT TRAILING COLD FRONT PUSHING INTO THE
AREA. KEPT CHANCE POPS TUE AS ANOTHER ROUND OF SHOWERS/STORMS COULD
AFFECT THE AREA AHEAD OF THE FRONT.
WED WILL MOST LIKELY BE A DRY DAY AS SUBSIDENCE TAKES PLACE BEHIND
EXITING LOW/SHORTWAVE BUT HAVE KEPT SLIGHT CHANCE POPS IN FCST AS
THERE IS STILL INSTABILITY PRESENT DUE TO A WARM AND MUGGY AIRMASS
IN PLACE.
THUR INTO NEXT WEEKEND...RIDGE BUILDS ACROSS THE CENTRAL CONUS
ALLOWING FOR UPR FLOW TO BECOME MORE NW ACROSS THE EASTERN SEABOARD.
THIS WILL BRING BOUTS OF NW FLOW CONVECTION WITH H85 MB BAROCLINIC
ZONE LOCATED IN THE VCNTY. HAVE PAINTED LOW CHANCE POPS FOR THIS
PERIOD AS OCNL SHORTWAVE ACTIVITY WILL AFFECT THE AREA.
TEMPS DURING THE PERIOD WILL BE QUITE WARM AND ABOVE CLIMO...WITH
THICKNESSES SUGGESTING HIGHS IN THE LOW TO OCNL MID 90S PERHAPS AT
TIMES. LOWS WILL BE MUGGY IN THE 70S.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 18Z SUNDAY/...
AS OF 130 PM SATURDAY...VFR CONDITIONS EXPECTED THROUGH MUCH OF
THE PERIOD. HOWEVER...ANTICIPATING SCHC SHOWER/THUNDERSTORM
ACTIVITY THIS AFTERNOON. ANY DEVELOPMENT AT OR NEAR TAF SITES WILL
LIKELY REDUCE VSBYS/LOWER CIGS TO SUB-VFR CRITERIA. AT THIS
POINT...FEEL THE DEVELOPMENT WILL BE WIDESPREAD IN COVERAGE. SO
HAVE ALL TAF SITES UNDER A VCTS THROUGH 01Z. NOT CONFIDENCE ENOUGH
IN EXACT LOCATION FORMATION TO PUT TEMPO GROUPS IN JUST YET.
CLOUDS/CONVECTIVE DEBRIS WILL DISSIPATE THROUGH THE EVENING HOURS
WITH SOME HIGH CLOUDS MOVING INTO THE AREA UNDER LIGHT SOUTHERLY
FLOW. PATCHY FOG IS POSSIBLE OVERNIGHT. WITH A BETTER INFLUX OF
LOW LEVEL MOISTURE...CALM WINDS AND ENOUGH CLEARING TAF SITES MAY
GET A BRIEF PERIOD OF MVFR FOG. CLOUDS WILL BE ON THE INCREASE
THROUGH SUNDAY AS A SHORTWAVE APPROACHES THE REGION. SCHC
SHOWER/THUNDERSTORM ACTIVITY AGAIN SUNDAY AFTERNOON UNDER
CONTINUAL SOUTHERLY FLOW.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...GENERALLY EXPECT VFR CONDITIONS WITH ONLY
OCCASIONAL PERIODS OF SHOWERS/STORMS PRODUCING MVFR CONDITIONS
THROUGH THE LONG TERM PERIOD. MAY BE SOME LIGHT FOG/STRATUS EACH
NIGHT IN THE LONG TERM AS WINDS WILL BE LIGHT TO CALM EACH EVENING.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 130 PM SATURDAY...FORECAST LOOKS GOOD. NO CHANGES NEEDED.
SEAS 1 TO 2 FEET AND SW FLOW AROUND 5-15KTS.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...PRES GRADIENT BETWEEN INLAND TROF AND
OFFSHORE HIGH PRESSURE WILL TIGHTEN SLIGHTLY WITH HEATING
TODAY...RESULTING IN S-SW WINDS INCREASING TO 10-15 KT THIS AFTN
AND GRADUALLY DIMINISH OVERNIGHT. SEAS GENERALLY REMAINING AROUND
2 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM SAT...THE PERIOD BEGINS WITH SOUTH TO SW FLOW THAT INC
A BIT ON SUN AS GRADIENT INC. IN GENERAL FLOW WILL REMAIN SOUTHERLY
INCREASING TO AROUND 15 KT SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
COULD SEE A FEW 4 FOOT SEAS IN THE OUTER WATERS IN THIS TIME FRAME.
MONDAY AFTERNOON INTO TUE THE GRADIENT WILL TIGHTEN FURTHER AS AN
AREA OF LOW PRESSURE TRACKS TO OUR NORTH WITH S TO SW FLOW
INCREASING TO 15 TO 20 KT AHEAD OF A TRAILING COLD FRONT. THIS WILL
ALLOW SEAS TO BUILD TO 4 TO 5 FEET ACROSS CENTRAL AND SOUTHERN OUTER
WATERS. THE COLD FRONT PASSES THROUGH THE WATERS TUE NIGHT AND
DISSIPATES BRINGING LIGHTER WINDS RETURNING TO SOUTHERLY BY LATE
WEDNESDAY AND SEAS RETURNING TO 2 TO 3 FEET. SOME DISAGREEMENT
TOWARDS THE END OF NEXT WEEK AS GFS BRINGS GUSTY NE WINDS TO THE
AREA...HOWEVER MORE LIKELY SCENARIO IS FOR WINDS TO REMAIN S TO SW
AS HIGH PRES REMAINS IN CONTROL OF THE SE SEABOARD AND CONDITIONS TO
REMAIN SUB SCA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM/LEP
SHORT TERM...JBM
LONG TERM...TL
AVIATION...LEP
MARINE...JBM/TL/LEP
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1031 AM EDT SAT AUG 16 2014
.SYNOPSIS...
INCREASING HEAT AND HUMIDITY WILL DEVELOP THROUGH THE WEEKEND AND
INTO EARLY NEXT WEEK AS A TYPICAL SUMMERTIME PATTERN DEVELOPS. A
WEAK COLD FRONT WILL APPROACH TUESDAY NIGHT BEFORE DISSIPATING
ACROSS THE AREA EARLY WEDNESDAY. HOT TEMPERATURES WITH HIGH
HUMIDITY ARE EXPECTED FOR THE MIDDLE AND LATTER PART OF THE
UPCOMING WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...THE MAIN FORECAST CHALLENGE CONTINUES TO
BE POPS. THE LATEST NAM IS VERY SPARSE ON THE COVERAGE WITH WHAT
LITTLE IT DEVELOPS LATER AROUND 0300 UTC. THIS APPEARS TO BE
ASSOCIATED WITH A SUBTLE SHORTWAVE. THE RAP CONTINUES TO SHOW MORE
COVERAGE FROM NOW THROUGH THE AFTERNOON HOURS. BASED ON THIS AND
THE FACT THERE ARE A FEW LIGHT SHOWERS POPPING UP IN HORRY
COUNTY...WILL CONTINUE TO ADVERTISE SLIGHT CHANCE POPS FOR THE
REMAINDER OF THE DAY. TEMPERATURE TRENDS LOOK GOOD.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...LONGWAVE TROUGH CENTERED OVER THE CANADIAN
MARITIMES WILL FLATTEN SUNDAY...WITH BRIEF SHORTWAVE RIDGING LIKELY
MOVING OVERHEAD DURING THE EVENING. THIS CREATES WESTERLY MID-LEVEL
FLOW WHICH DRIES THE MIDDLE PORTIONS OF THE COLUMN...WHILE AT THE
SAME TIME HELPS TO WARM TEMPS TO ABOVE NORMAL AT THE SURFACE. BROAD
RETURN FLOW AROUND AN EXPANDING AREA OF HIGH PRESSURE OFFSHORE WILL
PUMP WARM/MOIST AIR INTO THE REGION IN THE LOWER PORTIONS OF THE
COLUMN...CAUSING INCREASED INSTABILITY TO SURFACE PARCELS SUNDAY.
HOWEVER...THE WARMING TEMPS IN THE 850-500MB LAYER COMBINED WITH THE
DRYING FLOW WILL INHIBIT WIDESPREAD CONVECTION. THUS...EVEN AS TEMPS
SOAR INTO THE LOW 90S...CONVECTION WILL BE LIMITED TO THE SEA-BREEZE
BOUNDARY...AND POP IS MAINTAINED ONLY IN THE SCHC RANGE. ANY STORMS
SUNDAY WILL WANE QUICKLY AFTER DARK...AND A WARM NIGHT IS EXPECTED
WITH LOWS ONLY FALLING INTO THE MID 70S AT THE COAST...LOW 70S
INLAND.
THE FOCUS ON MONDAY REVOLVES AROUND A FAIRLY POTENT...BUT
WEAKENING...500MB LOW TRAVERSING JUST NORTH OF THE AREA. AHEAD OF
THIS FEATURE...CONTINUED SHORTWAVE RIDGING COMBINED WITH SW SURFACE
FLOW WILL DRIVE TEMPS AGAIN TO AROUND 95 AWAY FROM THE COAST...AND
AROUND 90 AT THE BEACHES. THE SURFACE REFLECTION OF THIS FEATURE IS
EXPECTED TO REMAIN NORTH OF THE NC/VA BORDER AS IT RACES EAST TO BE
OFFSHORE BY TUESDAY...THUS NO DIRECT IMPACTS ARE EXPECTED LOCALLY.
HOWEVER...INCREASING MOISTURE AS WELL AS SLOWLY THINNING 1000-500MB
THICKNESSES ASSOCIATED WITH THIS IMPULSE WILL CREATE HIGHER POP
CHANCES MONDAY...WITH SCATTERED CONVECTION EXPECTED.
ADDITIONALLY...SHOWERS/STORMS MAY PERSIST TEMPORALLY BEYOND TYPICAL
DIURNAL ACTIVITY AS COLUMN MOISTURE INCREASES THROUGH THE NIGHT
THANKS TO THE CLOSEST APPROACH OF THE MID-LEVEL AND SURFACE
FEATURES. MINS MONDAY NIGHT WILL BE VERY WARM...WITH UPPER 70S
EXPECTED AT THE COAST AND MID 70S WELL INLAND.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...WEAK COLD FRONT WILL APPROACH ON
TUESDAY...POSSIBLY CROSSING THE AREA BEFORE WASHING OUT BY EARLY
WEDNESDAY. THEREAFTER...A PERIOD OF HOT AND HUMID WEATHER IS
EXPECTED FOR THE REMAINDER OF NEXT WEEK.
MID-LEVEL IMPULSE AND ASSOCIATED SURFACE LOW WILL BE MOVING OFF THE
VIRGINIA COAST AT THE START OF THE PERIOD. A WEAK COLD FRONT
TRAILING THE SURFACE FEATURE WILL TRY TO DROP SOUTH INTO THE AREA
LATE TUESDAY NIGHT...BUT IT WILL BECOME ORIENTED PARALLEL TO THE
MID-LEVEL FLOW AND LIKELY STALL JUST NORTH OF THE CWA...ALTHOUGH A
BRIEF WIND SHIFT TO THE NORTH IS POSSIBLE VERY LATE TUESDAY
NIGHT...ESPECIALLY ACROSS NC COUNTIES. LITTLE OTHER IMPACTS ARE
ANTICIPATED...AND TUESDAY WILL FEATURE SLIGHTLY ABOVE NORMAL TEMPS
WITH DIURNAL TSTM CHANCES.
BY WEDNESDAY...AND THEN THROUGH THE REST OF THE PERIOD...EXPANSIVE
UPPER RIDGE BEGINS TO BUILD BACK TO THE WEST AND BLOSSOM ACROSS THE
SOUTHEAST. THE SURFACE HIGH OVER THE WESTERN ATLANTIC IS FORCED TO
RE-ORGANIZE TO THE WEST AS WELL...STRENGTHENING ALONG THE SOUTHERN
TIER...WHICH SUGGESTS A PERIOD OF WELL-ABOVE NORMAL TEMPS FOR LATE
IN THE WEEK. THE ECM AND GFS DISAGREE ON EXACTLY WHERE THE RIDGE
AXIS WILL SETUP...WITH THE ECM KEEPING IT NEARLY OVERHEAD THIS
AREA...WHILE THE GFS DEPICTS IT ACROSS THE MS VLY. WHILE THIS WILL
HAVE LITTLE IMPACT ON TEMPS...WHICH SHOULD BE AROUND 5 DEGREES ABOVE
NORMAL (ALTHOUGH ECM WOULD BE A BIT WARMER)...PRECIP CHANCES WILL BE
DECREASED IN THE ECM SOLUTION VERSUS THE GFS. WILL LEAN ON THE
WARMER/DRIER ECM WHICH IS FAVORED BY WPC AND HAS BEEN MORE
CONSISTENT. STILL WILL EXPECT TO SEE AT LEAST ISOLATED DIURNAL
CONVECTION EACH DAY...AS A TYPICAL SUMMERTIME PATTERN FINALLY
RETURNS TO THE AREA. ADDITIONALLY...WITH THE HIGH TEMPS AND HIGH
DEWPOINTS...EXPECT HEAT INDICES TO REACH OR EXCEED 100 ACROSS THE
AREA ALL OF NEXT WEEK.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...AREAS OF MVFR DUE TO FOG EARLY THIS MORNING AND AGAIN
TOWARDS THE END OF THE VALID PERIOD. OTHERWISE EXPECT VFR WITH
ISOLATED TO SCATTERED SHRA/TSRA POSSIBLE THIS AFTERNOON.
NEARLY CLEAR SKIES AND LIGHT WINDS PREVAIL ACROSS THE AREA THIS
MORNING...WITH SOME TAF SITES OBSERVING MVFR FOG. EXPECT FOG TO
DISSIPATE OVER THE NEXT FEW HOURS GIVING WAY TO VFR. INTO THE
AFTERNOON HOURS WILL SEE INCREASING SOUTHERLY WINDS AROUND 10 KTS OR
LESS AND FEW/SCT CLOUDS AROUND 4-5KFT. GIVEN ATMOSPHERIC CONDITIONS
AND LATEST FCST SOUNDINGS...COULD NOT RULE OUT ISOLATED TO SCATTERED
SHRA/TSRA...ESPECIALLY ALONG THE AFTERNOON SEABREEZE. THIS
EVENING...ANY CONVECTION WILL TAPER OFF AND VFR WILL PREVAIL WITH
CLEARING SKIES AND WINDS BECOMING LIGHT. GIVEN IDEAL RADIATIONAL
COOLING CONDITIONS...ANTICIPATE MVFR FOG...ESPECIALLY
INLAND...TOWARDS THE END OF THE VALID TAF PERIOD.
EXTENDED OUTLOOK...INCREASING CHANCES FOR ISOLATED TO SCATTERED AFTN
SHOWERS/TSTMS MONDAY THROUGH WEDNESDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY...WINDS AND SEAS LOOK GOOD WITH THE MORNING
UPDATE. JMPN7 IS REPORTING WIND SPEEDS IN THE SINGLE DIGITS AND
41110 SHOWING 1.3 FEET. BENIGN CONDITIONS WILL CONTINUE THROUGH THE
AFTERNOON HOURS. NO CHANGES TO THE FORECAST.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...HIGH PRESSURE EXPANDING OFFSHORE WILL BE THE
PRIMARY FEATURE TO THE MARINE CONDITIONS DURING THE SHORT
TERM...PRODUCING SW WINDS THROUGH THE PERIOD. INITIALLY...THESE
WINDS WILL BE OF MODERATE STRENGTH...AROUND 10 KTS...BUT WILL
GRADUALLY INCREASE...AND BECOME 15-20 KTS MONDAY AHEAD OF AN
APPROACHING COLD FRONT. SEAS WILL BUILD IN RESPONSE TO THE
STRENGTHENING WINDS...RISING FROM 2-3 FT MUCH OF SUNDAY...TO 3-5 FT
MONDAY NIGHT.
LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...HIGH PRESSURE OFFSHORE AND A WEAK COLD FRONT
APPROACHING FROM THE NORTH WILL PINCH THE PRESSURE GRADIENT
TUESDAY...DRIVING SW WINDS TO 15-20 KTS MUCH OF THE DAY. THERE IS
STILL SOME UNCERTAINTY INTO HOW FAR SOUTH THIS FRONT WILL REACH
BEFORE WASHING OUT...BUT EXPECT A BRIEF PERIOD OF NORTHERLY WINDS
ACROSS THE NC WATERS VERY EARLY WEDNESDAY...BEFORE SW WINDS RETURN
THROUGH THE END OF THE PERIOD...BUT AT SPEEDS OF ONLY AROUND 10 KTS.
SEAS WILL BE DRIVEN PRIMARILY BY A WIND-WAVE TUESDAY...REACHING 3-5
FT TUESDAY...BEFORE FALLING WEDNESDAY TO 2-3 FT ON THE EASING WINDS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...SHK
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
945 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM OFFSHORE THROUGH
EARLY NEXT WEEK WITH A TROUGH OF LOW PRESSURE INLAND. A WEAK COLD
FRONT WILL MOVE IN FROM THE NORTH TUESDAY NIGHT...THEN RETURN
NORTH WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 945 AM SATURDAY...WITH THE SHORTWAVE EXITING TO THE
NE...HAVE AN ISOLATED SHOWER THREAT ACROSS THE NORTH THROUGH THE
NEXT COUPLE HOURS. HIGH CLOUDS ARE ERODING WITH PLENTY OF HEATING.
ADJUSTED HOURLY TEMPS SLIGHTLY AS THEY CLIMB INTO THE 80S.
OTHERWISE...FORECAST IS ON TRACK FOR A TYPICAL SUMMER-LIKE DAY
WITH INLAND CONVECTION POSSIBLE IN THE AFTERNOON..
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...ISOLATED SHOWER/TSTM THREAT WILL CONTINUE
ACROSS NRN HALF OF AREA THROUGH 8 AM AS ADDITIONAL ACTIVITY
DEVELOPING SOUTH OF MAIN AREA NEAR NC/VA LINE. HRRR HAS GOOD
HANDLE ON THIS ACTIVITY. ISOLATED THREAT PSBL OVER NE SECTIONS 8
AM TIL NOON AND CONTINUED PREVIOUS FCST 20 POP THERE. SHRT WV
ENERGY...HEATING...INLAND TROF AND SEA BREEZE SUPPORT ISOLATED
SHOWERS/TSTMS INLAND OF COAST THIS AFTN. HIGH TEMPS AROUND 90
INLAND WITH MID 80S OBX.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...ISOALATED CONVECTIVE THREAT WILL CONTINUE
INLAND THIS EVENING...WITH ANOTHER SHRT WV MOVING IN FROM W-NW.
MODELS SUPPORT ACTIVITY DIMINISHING OVERNIGHT...BUT SOME
REDEVELOPMENT PSBL ALONG COAST NEAR MORNING...THUS NO CHANGE TO
PREVIOUS FCST. MIN TEMPS FROM AROUND 70 INLAND TO MID 70S COAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 330 AM SAT...LONG TERM PERIOD WILL BE DOMINATED BY WARMING
TEMPERATURE PATTERN WITH OCCASIONAL BOUTS OF SHOWERS AND
THUNDERSTORMS.
LOW LEVEL SFC FLOW RETURNS TO THE AREA THIS WEEKEND WITH INCREASING
TEMPS...THOUGH DEWPOINTS WILL BE A BIT SLOWER TO RESPOND SO STILL
EXPECTING NEAR CLIMO LOWS OVERNIGHT. CONTINUED TYPICAL SUMMERY
PATTERN ON SUNDAY WITH ISOLATED AFTERNOON THUNDERSHOWERS ALONG SEA
BREEZE FRONT.
MED/LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH RESPECT TO
SYNOPTIC REGIME THROUGH THE LONG TERM...WITH SLOWLY BUILDING HEIGHTS
AS MID ATLANTIC RIDGE BUILDS INTO THE DEEP SOUTH. THIS WILL BRING
HOT TEMPS AND HIGH HUMIDITY VALS AS LAYER MIX RATIOS INC TO AROUND
16 G/KG EARLY TO MID NEXT WEEK. THE REGION LOOKS TO REMAIN JUST
SOUTH OF THE STORM TRACK...THOUGH COULD BE AFFECTED BY A SYSTEM
EXPECTED TO TRAVERSE THE MID ATLANTIC REGION IN THE MON NIGHT TO TUE
TIME FRAME AND THEN AGAIN MID TO LATE WEEK.
FOR MONDAY AFTERNOON AND EVENING...HAVE AN INCREASING POP TREND AS
MODEL SUITE IS IN GOOD AGREEMENT ON A COMPACT SHORTWAVE TRAVERSING
THE MID ATLANTIC STATES...WITH SFC REFLECTION NOTED ACROSS THE
DELMARVA PENINSULA MON NIGHT. TRICKY TO PIN DOWN WHERE/WHEN
DEVELOPMENT WILL TAKE PLACE IN THIS CONVECTIVE REGIME...SO HAVE
CAPPED POPS IN THE CHANCE RANGE...LOWEST ACROSS THE SOUTHERN FA.
POTENTIAL MCS ACTIVITY COULD BRING A GOOD AMOUNT OF QPF TO PARTS OF
E NC THROUGH MON NIGHT. IN ADDITION...LAYER MIX RATIOS INC QUITE A
BIT INTO THE 17 G/KG RANGE WITH PWATS AROUND 2 INCHES. THE LOW MOVES
OFFSHORE ON TUE WITH ATTENDANT TRAILING COLD FRONT PUSHING INTO THE
AREA. KEPT CHANCE POPS TUE AS ANOTHER ROUND OF SHOWERS/STORMS COULD
AFFECT THE AREA AHEAD OF THE FRONT.
WED WILL MOST LIKELY BE A DRY DAY AS SUBSIDENCE TAKES PLACE BEHIND
EXITING LOW/SHORTWAVE BUT HAVE KEPT SLIGHT CHANCE POPS IN FCST AS
THERE IS STILL INSTABILITY PRESENT DUE TO A WARM AND MUGGY AIRMASS
IN PLACE.
THUR INTO NEXT WEEKEND...RIDGE BUILDS ACROSS THE CENTRAL CONUS
ALLOWING FOR UPR FLOW TO BECOME MORE NW ACROSS THE EASTERN SEABOARD.
THIS WILL BRING BOUTS OF NW FLOW CONVECTION WITH H85 MB BAROCLINIC
ZONE LOCATED IN THE VCNTY. HAVE PAINTED LOW CHANCE POPS FOR THIS
PERIOD AS OCNL SHORTWAVE ACTIVITY WILL AFFECT THE AREA.
TEMPS DURING THE PERIOD WILL BE QUITE WARM AND ABOVE CLIMO...WITH
THICKNESSES SUGGESTING HIGHS IN THE LOW TO OCNL MID 90S PERHAPS AT
TIMES. LOWS WILL BE MUGGY IN THE 70S.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 12Z SUNDAY/...
AS OF 720 AM SATURDAY...VFR EXPECTED THROUGH THIS EVENING...THEN
PERIOD OF MVFR VSBYS LIKELY LATE TONIGHT MOST SITES. ISOLATED
CONVECTIVE ACTIVITY PSBL WITH SEA BREEZE AND INLAND TROFFING BUT
COVERAGE TOO LIMITED TO MENTION IN TAFS. LATEST GDNC SUPPORTS LIGHT
FOG/HAZE LATE TONIGHT WITH WINDS DECOUPLING AND GRADUALLY INCREASING
LOW LVL MSTR.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...GENERALLY EXPECT VFR CONDITIONS WITH ONLY
OCCASIONAL PERIODS OF SHOWERS/STORMS PRODUCING MVFR CONDITIONS
THROUGH THE LONG TERM PERIOD. MAY BE SOME LIGHT FOG/STRATUS EACH
NIGHT IN THE LONG TERM AS WINDS WILL BE LIGHT TO CALM EACH EVENING.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 945 AM SATURDAY...FORECAST LOOKS GOOD. NO CHANGES NEEDED.
ISOLATED SHOWERS ACROSS THE NORTHERN WATERS THIS MORNING. SEAS 2
FEET AND SW/W FLOW AROUND 5-10KTS.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...PRES GRADIENT BETWEEN INLAND TROF AND
OFFSHORE HIGH PRESSURE WILL TIGHTEN SLIGHTLY WITH HEATING
TODAY...RESULTING IN S-SW WINDS INCREASING TO 10-15 KT THIS AFTN
AND GRADUALLY DIMINISH OVERNIGHT. SEAS GENERALLY REMAINING AROUND
2 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM SAT...THE PERIOD BEGINS WITH SOUTH TO SW FLOW THAT INC
A BIT ON SUN AS GRADIENT INC. IN GENERAL FLOW WILL REMAIN SOUTHERLY
INCREASING TO AROUND 15 KT SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
COULD SEE A FEW 4 FOOT SEAS IN THE OUTER WATERS IN THIS TIME FRAME.
MONDAY AFTERNOON INTO TUE THE GRADIENT WILL TIGHTEN FURTHER AS AN
AREA OF LOW PRESSURE TRACKS TO OUR NORTH WITH S TO SW FLOW
INCREASING TO 15 TO 20 KT AHEAD OF A TRAILING COLD FRONT. THIS WILL
ALLOW SEAS TO BUILD TO 4 TO 5 FEET ACROSS CENTRAL AND SOUTHERN OUTER
WATERS. THE COLD FRONT PASSES THROUGH THE WATERS TUE NIGHT AND
DISSIPATES BRINGING LIGHTER WINDS RETURNING TO SOUTHERLY BY LATE
WEDNESDAY AND SEAS RETURNING TO 2 TO 3 FEET. SOME DISAGREEMENT
TOWARDS THE END OF NEXT WEEK AS GFS BRINGS GUSTY NE WINDS TO THE
AREA...HOWEVER MORE LIKELY SCENARIO IS FOR WINDS TO REMAIN S TO SW
AS HIGH PRES REMAINS IN CONTROL OF THE SE SEABOARD AND CONDITIONS TO
REMAIN SUB SCA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM/LEP
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/TL/LEP
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
739 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM OFFSHORE THROUGH
EARLY NEXT WEEK WITH A TROUGH OF LOW PRESSURE INLAND. A WEAK COLD
FRONT WILL MOVE IN FROM THE NORTH TUESDAY NIGHT...THEN RETURN
NORTH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 715 AM SATURDAY...EXTENDED 20 POP ACROSS NRN HALF OF AREA THIS
MORNING AND ADJUSTED SKY COVER BASED ON LATEST STLT TRENDS.
CONVECTIVE ACTIVITY STILL MOVING ACROSS JUST N OF AREA AND CANNOT
RULE OUT ISOLATED SHOWER NRN SECTIONS WITH SHRT WV MOVING ACROSS AND
WEAK SFC BNDRY IN VCTY. REST OF FCST ON TRACK.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...ISOLATED SHOWER/TSTM THREAT WILL CONTINUE
ACROSS NRN HALF OF AREA THROUGH 8 AM AS ADDITIONAL ACTIVITY
DEVELOPING SOUTH OF MAIN AREA NEAR NC/VA LINE. HRRR HAS GOOD HANDLE
ON THIS ACTIVITY. ISOLATED THREAT PSBL OVER NE SECTIONS 8 AM TIL
NOON AND CONTINUED PREVIOUS FCST 20 POP THERE. SHRT WV
ENERGY...HEATING...INLAND TROF AND SEA BREEZE SUPPORT ISOLATED
SHOWERS/TSTMS INLAND OF COAST THIS AFTN. HIGH TEMPS AROUND 90 INLAND
WITH MID 80S OBX.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...ISOALATED CONVECTIVE THREAT WILL CONTINUE
INLAND THIS EVENING...WITH ANOTHER SHRT WV MOVING IN FROM W-NW.
MODELS SUPPORT ACTIVITY DIMINISHING OVERNIGHT...BUT SOME
REDEVELOPMENT PSBL ALONG COAST NEAR MORNING...THUS NO CHANGE TO
PREVIOUS FCST. MIN TEMPS FROM AROUND 70 INLAND TO MID 70S COAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 330 AM SAT...LONG TERM PERIOD WILL BE DOMINATED BY WARMING
TEMPERATURE PATTERN WITH OCCASIONAL BOUTS OF SHOWERS AND
THUNDERSTORMS.
LOW LEVEL SFC FLOW RETURNS TO THE AREA THIS WEEKEND WITH INCREASING
TEMPS...THOUGH DEWPOINTS WILL BE A BIT SLOWER TO RESPOND SO STILL
EXPECTING NEAR CLIMO LOWS OVERNIGHT. CONTINUED TYPICAL SUMMERY
PATTERN ON SUNDAY WITH ISOLATED AFTERNOON THUNDERSHOWERS ALONG SEA
BREEZE FRONT.
MED/LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH RESPECT TO
SYNOPTIC REGIME THROUGH THE LONG TERM...WITH SLOWLY BUILDING HEIGHTS
AS MID ATLANTIC RIDGE BUILDS INTO THE DEEP SOUTH. THIS WILL BRING
HOT TEMPS AND HIGH HUMIDITY VALS AS LAYER MIX RATIOS INC TO AROUND
16 G/KG EARLY TO MID NEXT WEEK. THE REGION LOOKS TO REMAIN JUST
SOUTH OF THE STORM TRACK...THOUGH COULD BE AFFECTED BY A SYSTEM
EXPECTED TO TRAVERSE THE MID ATLANTIC REGION IN THE MON NIGHT TO TUE
TIME FRAME AND THEN AGAIN MID TO LATE WEEK.
FOR MONDAY AFTERNOON AND EVENING...HAVE AN INCREASING POP TREND AS
MODEL SUITE IS IN GOOD AGREEMENT ON A COMPACT SHORTWAVE TRAVERSING
THE MID ATLANTIC STATES...WITH SFC REFLECTION NOTED ACROSS THE
DELMARVA PENINSULA MON NIGHT. TRICKY TO PIN DOWN WHERE/WHEN
DEVELOPMENT WILL TAKE PLACE IN THIS CONVECTIVE REGIME...SO HAVE
CAPPED POPS IN THE CHANCE RANGE...LOWEST ACROSS THE SOUTHERN FA.
POTENTIAL MCS ACTIVITY COULD BRING A GOOD AMOUNT OF QPF TO PARTS OF
E NC THROUGH MON NIGHT. IN ADDITION...LAYER MIX RATIOS INC QUITE A
BIT INTO THE 17 G/KG RANGE WITH PWATS AROUND 2 INCHES. THE LOW MOVES
OFFSHORE ON TUE WITH ATTENDANT TRAILING COLD FRONT PUSHING INTO THE
AREA. KEPT CHANCE POPS TUE AS ANOTHER ROUND OF SHOWERS/STORMS COULD
AFFECT THE AREA AHEAD OF THE FRONT.
WED WILL MOST LIKELY BE A DRY DAY AS SUBSIDENCE TAKES PLACE BEHIND
EXITING LOW/SHORTWAVE BUT HAVE KEPT SLIGHT CHANCE POPS IN FCST AS
THERE IS STILL INSTABILITY PRESENT DUE TO A WARM AND MUGGY AIRMASS
IN PLACE.
THUR INTO NEXT WEEKEND...RIDGE BUILDS ACROSS THE CENTRAL CONUS
ALLOWING FOR UPR FLOW TO BECOME MORE NW ACROSS THE EASTERN SEABOARD.
THIS WILL BRING BOUTS OF NW FLOW CONVECTION WITH H85 MB BAROCLINIC
ZONE LOCATED IN THE VCNTY. HAVE PAINTED LOW CHANCE POPS FOR THIS
PERIOD AS OCNL SHORTWAVE ACTIVITY WILL AFFECT THE AREA.
TEMPS DURING THE PERIOD WILL BE QUITE WARM AND ABOVE CLIMO...WITH
THICKNESSES SUGGESTING HIGHS IN THE LOW TO OCNL MID 90S PERHAPS AT
TIMES. LOWS WILL BE MUGGY IN THE 70S.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 12Z SUNDAY/...
AS OF 720 AM SATURDAY...VFR EXPECTED THROUGH THIS EVENING...THEN
PERIOD OF MVFR VSBYS LIKELY LATE TONIGHT MOST SITES. ISOLATED
CONVECTIVE ACTIVITY PSBL WITH SEA BREEZE AND INLAND TROFFING BUT
COVERAGE TOO LIMITED TO MENTION IN TAFS. LATEST GDNC SUPPORTS LIGHT
FOG/HAZE LATE TONIGHT WITH WINDS DECOUPLING AND GRADUALLY INCREASING
LOW LVL MSTR.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...GENERALLY EXPECT VFR CONDITIONS WITH ONLY
OCCASIONAL PERIODS OF SHOWERS/STORMS PRODUCING MVFR CONDITIONS
THROUGH THE LONG TERM PERIOD. MAY BE SOME LIGHT FOG/STRATUS EACH
NIGHT IN THE LONG TERM AS WINDS WILL BE LIGHT TO CALM EACH EVENING.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 715 AM SATURDAY...EXTENDED SLIGHT CHANCE OF SHOWERS OVER NRN
WATERS THIS MORNING...NO CHAGNES TO WINDS/SEAS.
/PREVIOUS DISCUSSION/
AS OF 400 AM SATURDAY...PRES GRADIENT BETWEEN INLAND TROF AND
OFFSHORE HIGH PRESSURE WILL TIGHTEN SLIGHTLY WITH HEATING
TODAY...RESULTING IN S-SW WINDS INCREASING TO 10-15 KT THIS AFTN AND
GRADUALLY DIMINISH OVERNIGHT. SEAS GENERALLY REMAINING AROUND 2 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM SAT...THE PERIOD BEGINS WITH SOUTH TO SW FLOW THAT INC
A BIT ON SUN AS GRADIENT INC. IN GENERAL FLOW WILL REMAIN SOUTHERLY
INCREASING TO AROUND 15 KT SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
COULD SEE A FEW 4 FOOT SEAS IN THE OUTER WATERS IN THIS TIME FRAME.
MONDAY AFTERNOON INTO TUE THE GRADIENT WILL TIGHTEN FURTHER AS AN
AREA OF LOW PRESSURE TRACKS TO OUR NORTH WITH S TO SW FLOW
INCREASING TO 15 TO 20 KT AHEAD OF A TRAILING COLD FRONT. THIS WILL
ALLOW SEAS TO BUILD TO 4 TO 5 FEET ACROSS CENTRAL AND SOUTHERN OUTER
WATERS. THE COLD FRONT PASSES THROUGH THE WATERS TUE NIGHT AND
DISSIPATES BRINGING LIGHTER WINDS RETURNING TO SOUTHERLY BY LATE
WEDNESDAY AND SEAS RETURNING TO 2 TO 3 FEET. SOME DISAGREEMENT
TOWARDS THE END OF NEXT WEEK AS GFS BRINGS GUSTY NE WINDS TO THE
AREA...HOWEVER MORE LIKELY SCENARIO IS FOR WINDS TO REMAIN S TO SW
AS HIGH PRES REMAINS IN CONTROL OF THE SE SEABOARD AND CONDITIONS TO
REMAIN SUB SCA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/TL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
501 AM EDT SAT AUG 16 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM OFFSHORE THROUGH
EARLY NEXT WEEK WITH A TROUGH OF LOW PRESSURE INLAND. A WEAK COLD
FRONT WILL MOVE IN FROM THE NORTH TUESDAY NIGHT...THEN RETURN
NORTH WEDNESDAY.
&&
.NEAR TERM /TODAY/...
AS OF 400 AM SATURDAY...ISOLATED SHOWER/TSTM THREAT WILL CONTINUE
ACROSS NRN HALF OF AREA THROUGH 8 AM AS ADDITIONAL ACTIVITY
DEVELOPING SOUTH OF MAIN AREA NEAR NC/VA LINE. HRRR HAS GOOD HANDLE
ON THIS ACTIVITY. ISOLATED THREAT PSBL OVER NE SECTIONS 8 AM TIL
NOON AND CONTINUED PREVIOUS FCST 20 POP THERE. SHRT WV
ENERGY...HEATING...INLAND TROF AND SEA BREEZE SUPPORT ISOLATED
SHOWERS/TSTMS INLAND OF COAST THIS AFTN. HIGH TEMPS AROUND 90 INLAND
WITH MID 80S OBX.
&&
.SHORT TERM /TONIGHT/...
AS OF 400 AM SATURDAY...ISOALATED CONVECTIVE THREAT WILL CONTINUE
INLAND THIS EVENING...WITH ANOTHER SHRT WV MOVING IN FROM W-NW.
MODELS SUPPORT ACTIVITY DIMINISHING OVERNIGHT...BUT SOME
REDEVELOPMENT PSBL ALONG COAST NEAR MORNING...THUS NO CHANGE TO
PREVIOUS FCST. MIN TEMPS FROM AROUND 70 INLAND TO MID 70S COAST.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 330 AM SAT...LONG TERM PERIOD WILL BE DOMINATED BY WARMING
TEMPERATURE PATTERN WITH OCCASIONAL BOUTS OF SHOWERS AND
THUNDERSTORMS.
LOW LEVEL SFC FLOW RETURNS TO THE AREA THIS WEEKEND WITH INCREASING
TEMPS...THOUGH DEWPOINTS WILL BE A BIT SLOWER TO RESPOND SO STILL
EXPECTING NEAR CLIMO LOWS OVERNIGHT. CONTINUED TYPICAL SUMMERY
PATTERN ON SUNDAY WITH ISOLATED AFTERNOON THUNDERSHOWERS ALONG SEA
BREEZE FRONT.
MED/LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT WITH RESPECT TO
SYNOPTIC REGIME THROUGH THE LONG TERM...WITH SLOWLY BUILDING HEIGHTS
AS MID ATLANTIC RIDGE BUILDS INTO THE DEEP SOUTH. THIS WILL BRING
HOT TEMPS AND HIGH HUMIDITY VALS AS LAYER MIX RATIOS INC TO AROUND
16 G/KG EARLY TO MID NEXT WEEK. THE REGION LOOKS TO REMAIN JUST
SOUTH OF THE STORM TRACK...THOUGH COULD BE AFFECTED BY A SYSTEM
EXPECTED TO TRAVERSE THE MID ATLANTIC REGION IN THE MON NIGHT TO TUE
TIME FRAME AND THEN AGAIN MID TO LATE WEEK.
FOR MONDAY AFTERNOON AND EVENING...HAVE AN INCREASING POP TREND AS
MODEL SUITE IS IN GOOD AGREEMENT ON A COMPACT SHORTWAVE TRAVERSING
THE MID ATLANTIC STATES...WITH SFC REFLECTION NOTED ACROSS THE
DELMARVA PENINSULA MON NIGHT. TRICKY TO PIN DOWN WHERE/WHEN
DEVELOPMENT WILL TAKE PLACE IN THIS CONVECTIVE REGIME...SO HAVE
CAPPED POPS IN THE CHANCE RANGE...LOWEST ACROSS THE SOUTHERN FA.
POTENTIAL MCS ACTIVITY COULD BRING A GOOD AMOUNT OF QPF TO PARTS OF
E NC THROUGH MON NIGHT. IN ADDITION...LAYER MIX RATIOS INC QUITE A
BIT INTO THE 17 G/KG RANGE WITH PWATS AROUND 2 INCHES. THE LOW MOVES
OFFSHORE ON TUE WITH ATTENDANT TRAILING COLD FRONT PUSHING INTO THE
AREA. KEPT CHANCE POPS TUE AS ANOTHER ROUND OF SHOWERS/STORMS COULD
AFFECT THE AREA AHEAD OF THE FRONT.
WED WILL MOST LIKELY BE A DRY DAY AS SUBSIDENCE TAKES PLACE BEHIND
EXITING LOW/SHORTWAVE BUT HAVE KEPT SLIGHT CHANCE POPS IN FCST AS
THERE IS STILL INSTABILITY PRESENT DUE TO A WARM AND MUGGY AIRMASS
IN PLACE.
THUR INTO NEXT WEEKEND...RIDGE BUILDS ACROSS THE CENTRAL CONUS
ALLOWING FOR UPR FLOW TO BECOME MORE NW ACROSS THE EASTERN SEABOARD.
THIS WILL BRING BOUTS OF NW FLOW CONVECTION WITH H85 MB BAROCLINIC
ZONE LOCATED IN THE VCNTY. HAVE PAINTED LOW CHANCE POPS FOR THIS
PERIOD AS OCNL SHORTWAVE ACTIVITY WILL AFFECT THE AREA.
TEMPS DURING THE PERIOD WILL BE QUITE WARM AND ABOVE CLIMO...WITH
THICKNESSES SUGGESTING HIGHS IN THE LOW TO OCNL MID 90S PERHAPS AT
TIMES. LOWS WILL BE MUGGY IN THE 70S.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM /THROUGH 06Z SUNDAY/...
AS OF 145 AM SATURDAY...AREA OF SHOWERS/TSTMS MOVING E ALONG NC/VA
LINE EXPECTED TO REMAIN N OF TAF SITES OVERNIGHT. PERIOD OF MVFR
VSBYS WITH LIGHT FOG/HZ 08Z-12Z MOST SITES WITH WINDS DECOUPLING
LATE. ISOLATED CONVECTIVE ACTIVITY PSBL WITH SEA BREEZE AND INLAND
TROFFING BUT COVERAGE TOO LIMITED TO MENTION IN TAFS. VFR CONDITIONS
EXPECTED TO PERSIST THROUGH THIS EVENING.
LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 330 AM SAT...GENERALLY EXPECT VFR CONDITIONS WITH ONLY
OCCASIONAL PERIODS OF SHOWERS/STORMS PRODUCING MVFR CONDITIONS
THROUGH THE LONG TERM PERIOD. MAY BE SOME LIGHT FOG/STRATUS EACH
NIGHT IN THE LONG TERM AS WINDS WILL BE LIGHT TO CALM EACH EVENING.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 400 AM SATURDAY...PRES GRADIENT BETWEEN INLAND TROF AND
OFFSHORE HIGH PRESSURE WILL TIGHTEN SLIGHTLY WITH HEATING
TODAY...RESULTING IN S-SW WINDS INCREASING TO 10-15 KT THIS AFTN AND
GRADUALLY DIMINISH OVERNIGHT. SEAS GENERALLY REMAINING AROUND 2 FT.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM SAT...THE PERIOD BEGINS WITH SOUTH TO SW FLOW THAT INC
A BIT ON SUN AS GRADIENT INC. IN GENERAL FLOW WILL REMAIN SOUTHERLY
INCREASING TO AROUND 15 KT SUNDAY AFTERNOON THROUGH SUNDAY NIGHT.
COULD SEE A FEW 4 FOOT SEAS IN THE OUTER WATERS IN THIS TIME FRAME.
MONDAY AFTERNOON INTO TUE THE GRADIENT WILL TIGHTEN FURTHER AS AN
AREA OF LOW PRESSURE TRACKS TO OUR NORTH WITH S TO SW FLOW
INCREASING TO 15 TO 20 KT AHEAD OF A TRAILING COLD FRONT. THIS WILL
ALLOW SEAS TO BUILD TO 4 TO 5 FEET ACROSS CENTRAL AND SOUTHERN OUTER
WATERS. THE COLD FRONT PASSES THROUGH THE WATERS TUE NIGHT AND
DISSIPATES BRINGING LIGHTER WINDS RETURNING TO SOUTHERLY BY LATE
WEDNESDAY AND SEAS RETURNING TO 2 TO 3 FEET. SOME DISAGREEMENT
TOWARDS THE END OF NEXT WEEK AS GFS BRINGS GUSTY NE WINDS TO THE
AREA...HOWEVER MORE LIKELY SCENARIO IS FOR WINDS TO REMAIN S TO SW
AS HIGH PRES REMAINS IN CONTROL OF THE SE SEABOARD AND CONDITIONS TO
REMAIN SUB SCA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/TL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1000 PM CDT SUN AUG 17 2014
.UPDATE...
ISSUED AT 1000 PM CDT SUN AUG 17 2014
WILL ALLOW SEVERE THUNDERSTORM WATCH 463 TO EXPIRE AT 10 PM.
DISORGANIZED CONVECTION CONTINUES ACROSS EASTERN PORTIONS OF
DICKEY AND LAMOURE COUNTIES...AND SHOULD BE MOVING OUT OF THE AREA
IN THE NEXT HOUR OR TWO. ISOLATED SHOWERS ARE DIMINISHING ACROSS
CENTRAL NORTH DAKOTA BUT WILL KEEP A SLIGHT CHANCE HERE THROUGH
MIDNIGHT. ANOTHER AREA OF CONVECTION WAS LOCATED OVER SOUTH
CENTRAL SASKATCHEWAN INTO FAR NORTHEAST MONTANA...POISED TO MOVE
INTO NORTHWEST NORTH DAKOTA. THIS AREA IS CLOSER TO THE UPPER LOW.
THE 00 UTC NAM...LATEST HRRR AND RAP INDICATE THIS WEAK CONVECTION
COULD HOLD TOGETHER PAST MIDNIGHT...THUS WILL KEEP A SLIGHT CHANCE
IN THE NORTHWEST PAST MIDNIGHT. WILL CONTINUE TO KEEP A CHANCE
THROUGH THE NIGHT OVER THE FAR SOUTHEAST CWA FOR NOW AS COLD FRONT
REMAINS BACK ACROSS CENTRAL NORTH DAKOTA. LATER SHIFTS MAY BE ABLE
TO CUT THIS BACK IF NO ADDITIONAL CONVECTION DEVELOPS.
UPDATE ISSUED AT 847 PM CDT SUN AUG 17 2014
REMOVED ANOTHER ROW OF COUNTIES FROM THE WESTERN PORTION OF THE
SEVERE THUNDERSTORM WATCH...PIERCE...SHERIDAN AND EMMONS. ALSO
TRIMMED BACK POPS A BIT OVER WESTERN NORTH DAKOTA. WILL TAKE A
CLOSER LOOK AT POPS WITH THE 10 PM UPDATE.
UPDATE ISSUED AT 643 PM CDT SUN AUG 17 2014
REMOVED HETTINGER...ADAMS...GRANT...MORTON...MERCER AND OLIVER
COUNTIES FROM SEVERE THUNDERSTORM WATCH 463. SEE THE RECENTLY
ISSUED SPC MESOSCALE DISCUSSION 1565 FOR DETAILS ON EXPECTED
TRENDS THROUGH 0045 UTC.
UPDATE ISSUED AT 401 PM CDT SUN AUG 17 2014
QUICK UPDATE TO ISSUE SEVERE THUNDERSTORM WATCH 463 VALID THROUGH
10 PM CDT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 315 PM CDT SUN AUG 17 2014
SEVERE CONVECTION WILL HIGHLIGHT THE SHORT TERM FORECAST FOR THIS
AFTERNOON AND EVENING.
OVERALL...IN AGREEMENT WITH SPC THINKING FOR CONVECTIVE EVOLUTION
THE REMAINDER OF THIS AFTERNOON AND EVENING. SEE SPC MESOSCALE
DISCUSSION #1563 FOR DETAILS. IN GENERAL...SOME UNCERTAINTY EXISTS
ON HOW MUCH CONVECTION WILL FILL IN ALONG THE COLD FRONT CROSSING
US HIGHWAY 85 AS OF 20 UTC...AS THE 17 AND INCOMING 18 UTC HRRR
ITERATIONS SHOW LITTLE BETWEEN THE ONGOING STORMS ACROSS THE NORTH
CENTRAL AND SOUTHWEST. THIS IS IN OPPOSITION TO THE 12 UTC WRF-ARW
AND NMM AND GLOBAL GUIDANCE WHICH WOULD SUGGEST MORE WIDESPREAD
STORMS BY 21-00 UTC. LARGE HAIL AND DAMAGING WINDS ARE THE PRIMARY
THREATS. WHILE LOW LEVEL SHEAR IS WEAK...CANNOT RULE OUT AN
ISOLATED TORNADO GIVEN POTENTIAL DISCRETE SUPERCELL STRUCTURES.
STORMS SHOULD BE LARGELY INTO THE RED RIVER VALLEY BY 03 UTC. NON-
SEVERE SCATTERED THUNDERSTORMS WILL CONTINUE NORTHWEST THROUGH
SUNSET...IN ASSOCIATION WITH THE UPPER LOW ALOFT.
FOR MONDAY...ADDITIONAL ISOLATED TO SCATTERED STORMS...BEST
CHANCES EAST...WILL LINGER GIVEN COLD TEMPERATURES ALOFT WITH THE
UPPER LEVEL LOW DEPARTING INTO MINNESOTA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 315 PM CDT SUN AUG 17 2014
AN ACTIVE WEATHER PATTERN WITH BELOW NORMAL TEMPERATURES WILL
HIGHLIGHT THE EXTENDED FORECAST.
AFTER A DRY TUESDAY...THE 12 UTC GUIDANCE SUITE IS IN AGREEMENT ON
A BROAD UPPER LEVEL TROUGH ESTABLISHING ITSELF ACROSS THE PACIFIC
NORTHWEST INTO THE NORTHERN PLAINS. THIS SUPPORTS A RATHER ACTIVE
WEATHER PERIOD WITH DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY THROUGH THE WEEKEND. TEMPERATURES ARE ALSO EXPECTED TO
BE BELOW NORMAL AS A RESULT...POSSIBLY ONLY IN THE MID TO UPPER
60S FOR SOME LOCATIONS BY NEXT WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 1000 PM CDT SUN AUG 17 2014
ALTHOUGH AN ISOLATED THUNDERSTORM IS STILL POSSIBLE...THREAT OF
STRONG CONVECTION HAS ALL BUT ENDED FOR ALL TAF SITES THIS
EVENING.
&&
.HYDROLOGY...
ISSUED AT 315 PM CDT SUN AUG 17 2014
GIVEN THE LATEST OBSERVATIONS THROUGH SUNDAY AFTERNOON...THE
PREVIOUS CONCERNS FOR THE KNIFE RIVER AT HAZEN AND THE APPLE CREEK
NEAR MENOKEN ARE GREATLY DECREASED. A CONTINUED RISE IS POSSIBLE
AT HAZEN AS RUNOFF FROM HEAVY RAIN CONTINUES TO PASS THROUGH THE
LOWER PORTIONS OF THE BASIN. HOWEVER...THE RIVER IS EXPECTED TO
REMAIN BELOW FLOOD STAGE. APPLE CREEK NEAR MENOKEN TO SOME
SURPRISE CONTINUES TO SHOW A NEAR COMPLETE LACK OF RESPONSE FROM HEAVY
RAINFALL...AND WILL COORDINATE WITH THE MISSOURI BASIN RIVER
FORECAST CENTER ON THE FORECAST. FINALLY...IN REGARDS TO THE AREAL
FLOOD WARNING ACROSS THE WEST...WILL CONTINUE TO GATHER
INFORMATION WHETHER THE WARNING CAN BE DROPPED IF OVERLAND
FLOODING IS BARRICADED AND SIGNED FOR PUBLIC AWARENESS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...TWH
HYDROLOGY...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1242 PM CDT SAT AUG 16 2014
.UPDATE...
ISSUED AT 1241 PM CDT SAT AUG 16 2014
THE 12 UTC DETERMINISTIC SUITE IS MUCH LESS ROBUST WITH CONVECTION
RE-DEVELOPING ACROSS WESTERN AND SOUTH CENTRAL NORTH DAKOTA THIS
AFTERNOON THROUGH TONIGHT...THUS...CUT BACK POPS FOR THESE AREAS.
TEH FOCUS FOR HEAVY RAIN THE REMAINDER OF THE AFTERNOON WILL BE
MOVING INTO THE SOUTHERN JAMES RIVER VALLEY WHERE SUNSHINE HAS
ALLOWED TEMPERATURES TO CLIMB TO NEAR 80F WITH DEW POINTS IN THE
LOWER 70S.
UPDATE ISSUED AT 915 AM CDT SAT AUG 16 2014
GIVEN RADAR TRENDS THROUGH 14 UTC...THE 10-11 UTC HRRR ITERATIONS
AND 00 UTC WRF-ARW/NMM SOLUTIONS...THE FOCUS FOR HEAVY RAINFALL
THIS MORNING AND AFTERNOON WILL BE ACROSS THE PRAIRIE POT HOLE
REGION OF SOUTH CENTRAL NORTH DAKOTA...SHIFTING INTO THE JAMES
RIVER VALLEY IN THE SOUTHEAST QUADRANT OF THE MESO-LOW EVIDENT ON
RADAR ACROSS THE HIGHWAY 83 CORRIDOR THIS MORNING. FLASH FLOOD
GUIDANCE IS IN THE 2-3 INCH PER HOUR RANGE FOR THESE AREAS.
ACROSS THE WEST...ESPECIALLY FOR THOSE AREAS WHICH WERE IMPACTED
BY VERY HEAVY RAIN OVER THE PAST 24-36 HOURS...MUCH OF THE DAY
WILL BE RATHER PRECIPITATION FREE. THE MAIN CONCERN IS FOR THIS
EVENING AND TONIGHT AS ANOTHER ROUND OF THUNDERSTORMS IS FORECAST
TO PROPAGATE INTO THE AREA FROM EASTERN MONTANA AS UPPER LEVEL
FORCING INCREASES AHEAD OF THE UPPER LEVEL LOW ACROSS THE NORTHERN
ROCKIES. FLASH FLOOD GUIDANCE IS WELL BELOW ONE INCH FOR MOST AREAS
ALREADY IMPACTED BY HEAVY RAIN...WITH ANY ADDITIONAL RAINFALL
AGGRAVATING THE ONGOING FLOODING.
UPDATE ISSUED AT 625 AM CDT SAT AUG 16 2014
BROAD AREA OF PRECIP CONTINUES TO STRETCH FROM NORTHWESTERN TO
SOUTH CENTRAL NORTH DAKOTA. GOING FORECAST ADDRESSES THIS WELL.
ONLY CHANGES MADE WERE TO PULL AREAS OF FOG FURTHER NORTH AND
WEST TO MATCH CURRENT OBS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT SAT AUG 16 2014
ISSUES IN THE SHORT TERM ARE ALL HYDROLOGIC WHICH IS BEING
FOCUSED ON IN THIS SHORT TERM SECTION.
LATEST RADAR TRENDS ARE FINALLY SHOWING A SLIGHT EASTWARD PUSH TO
THE LARGE AREA OF HEAVY RAIN OVER THE CENTRAL PART OF WESTERN
NORTH DAKOTA. THIS WILL BE WELCOME NEWS TO THE FOLKS IN DUNN
COUNTY WHERE SIGNIFICANT OVERLAND FLOODING WAS OCCURRING. THE
FLOOD WARNING CONTINUES FOR THAT CENTRAL PART OF WESTERN NORTH
DAKOTA THROUGH THE DAY SATURDAY. AS THE BACK EDGE OF THE RAIN AREA
WAS SHOWING A SLIGHT PUSH TO THE EAST...THE EASTERN EDGE OF THE
RAIN WAS ADVANCING MORE QUICKLY THROUGH MCLEAN AND MERCER
COUNTIES. AT THE SAME TIME NEW SHOWER/STORM DEVELOPMENT WAS
OCCURRING IN THE MANDAN-BISMARCK-STEELE AREAS.
DIFFLUENT FLOW ALOFT CONTINUES TODAY WITH SHORT WAVE ENERGY
ROTATING AROUND THE MAIN CLOSED H5 LOW IN SOUTHERN ALBERTA CANADA.
THIS MEANS A CONTINUED HIGH CHANCE FOR RAIN ACROSS THE WESTERN AND
CENTRAL PARTS OF THE FORECAST AREA INTO THIS AFTERNOON...SHIFTING
EAST BY LATE DAY.
OVERLAND FLOOD WARNING CONTINUES FOR MCKENZIE...DUNN...GOLDEN VALLEY...
BILLINGS...STARK...AND WESTERN MERCER AND WESTERN MORTON COUNTIES
THROUGH THE AFTERNOON.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT AUG 16 2014
MAIN CHALLENGE FOR THE EXTENDED IS CONTINUED PRECIPITATION CHANCES
TO START THE UPCOMING WEEK. CENTER OF UPPER LOW WILL PUSH ACROSS
SOUTHERN SASKATCHEWAN ON SUNDAY...AND THROUGH SOUTHERN MANITOBA
SUNDAY NIGHT INTO EARLY MONDAY. EXPECT PRECIP FOCUS TO START OUT
IN WEST-CENTRAL DURING THE DAY ON SUNDAY...THEN WORK TOWARDS THE
EAST SUNDAY NIGHT/EARLY MONDAY WITH PRECIP TAPERING FROM WEST TO
EAST THROUGH THE DAY ON MONDAY. EXPECT A QUIET PERIOD ON TUESDAY
AS FAST MOVING RIDGE PASSES OVER BEHIND DEPARTING SYSTEM BEFORE
SOUTHWESTERLY FLOW SETS UP OVER THE AREA. MODELS DIFFER SOME ON
HOW STRONG THIS FLOW IS...BUT THE MAIN POINT IS THAT THIS WILL
BRING THE NEXT ROUND OF PRECIPITATION CHANCES TO THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1241 PM CDT SAT AUG 16 2014
MVFR/IFR CONDITIONS IN SHOWERS AND THUNDERSTORMS IS
EXPECTED AT KBIS/KMOT/KJMS THIS AFTERNOON...POSSIBLY CONTINUING
INTO THE EVENING AT KJMS. ANOTHER ROUND OF POSSIBLY SEVERE STORMS
IS EXPECTED ACROSS THE AREA ON SUNDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...JPM
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
915 AM CDT SAT AUG 16 2014
.UPDATE...
ISSUED AT 915 AM CDT SAT AUG 16 2014
GIVEN RADAR TRENDS THROUGH 14 UTC...THE 10-11 UTC HRRR ITERATIONS
AND 00 UTC WRF-ARW/NMM SOLUTIONS...THE FOCUS FOR HEAVY RAINFALL
THIS MORNING AND AFTERNOON WILL BE ACROSS THE PRAIRIE POT HOLE
REGION OF SOUTH CENTRAL NORTH DAKOTA...SHIFTING INTO THE JAMES
RIVER VALLEY IN THE SOUTHEAST QUADRANT OF THE MESO-LOW EVIDENT ON
RADAR ACROSS THE HIGHWAY 83 CORRIDOR THIS MORNING. FLASH FLOOD
GUIDANCE IS IN THE 2-3 INCH PER HOUR RANGE FOR THESE AREAS.
ACROSS THE WEST...ESPECIALLY FOR THOSE AREAS WHICH WERE IMPACTED
BY VERY HEAVY RAIN OVER THE PAST 24-36 HOURS...MUCH OF THE DAY
WILL BE RATHER PRECIPITATION FREE. THE MAIN CONCERN IS FOR THIS
EVENING AND TONIGHT AS ANOTHER ROUND OF THUNDERSTORMS IS FORECAST
TO PROPAGATE INTO THE AREA FROM EASTERN MONTANA AS UPPER LEVEL
FORCING INCREASES AHEAD OF THE UPPER LEVEL LOW ACROSS THE NORTHERN
ROCKIES. FLASH FLOOD GUIDANCE IS WELL BELOW ONE INCH FOR MOST AREAS
ALREADY IMPACTED BY HEAVY RAIN...WITH ANY ADDITIONAL RAINFALL
AGGRAVATING THE ONGOING FLOODING.
UPDATE ISSUED AT 625 AM CDT SAT AUG 16 2014
BROAD AREA OF PRECIP CONTINUES TO STRETCH FROM NORTHWESTERN TO
SOUTH CENTRAL NORTH DAKOTA. GOING FORECAST ADDRESSES THIS WELL.
ONLY CHANGES MADE WERE TO PULL AREAS OF FOG FURTHER NORTH AND
WEST TO MATCH CURRENT OBS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT SAT AUG 16 2014
ISSUES IN THE SHORT TERM ARE ALL HYDROLOGIC WHICH IS BEING
FOCUSED ON IN THIS SHORT TERM SECTION.
LATEST RADAR TRENDS ARE FINALLY SHOWING A SLIGHT EASTWARD PUSH TO
THE LARGE AREA OF HEAVY RAIN OVER THE CENTRAL PART OF WESTERN
NORTH DAKOTA. THIS WILL BE WELCOME NEWS TO THE FOLKS IN DUNN
COUNTY WHERE SIGNIFICANT OVERLAND FLOODING WAS OCCURRING. THE
FLOOD WARNING CONTINUES FOR THAT CENTRAL PART OF WESTERN NORTH
DAKOTA THROUGH THE DAY SATURDAY. AS THE BACK EDGE OF THE RAIN AREA
WAS SHOWING A SLIGHT PUSH TO THE EAST...THE EASTERN EDGE OF THE
RAIN WAS ADVANCING MORE QUICKLY THROUGH MCLEAN AND MERCER
COUNTIES. AT THE SAME TIME NEW SHOWER/STORM DEVELOPMENT WAS
OCCURRING IN THE MANDAN-BISMARCK-STEELE AREAS.
DIFFLUENT FLOW ALOFT CONTINUES TODAY WITH SHORT WAVE ENERGY
ROTATING AROUND THE MAIN CLOSED H5 LOW IN SOUTHERN ALBERTA CANADA.
THIS MEANS A CONTINUED HIGH CHANCE FOR RAIN ACROSS THE WESTERN AND
CENTRAL PARTS OF THE FORECAST AREA INTO THIS AFTERNOON...SHIFTING
EAST BY LATE DAY.
OVERLAND FLOOD WARNING CONTINUES FOR MCKENZIE...DUNN...GOLDEN VALLEY...
BILLINGS...STARK...AND WESTERN MERCER AND WESTERN MORTON COUNTIES
THROUGH THE AFTERNOON.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT AUG 16 2014
MAIN CHALLENGE FOR THE EXTENDED IS CONTINUED PRECIPITATION CHANCES
TO START THE UPCOMING WEEK. CENTER OF UPPER LOW WILL PUSH ACROSS
SOUTHERN SASKATCHEWAN ON SUNDAY...AND THROUGH SOUTHERN MANITOBA
SUNDAY NIGHT INTO EARLY MONDAY. EXPECT PRECIP FOCUS TO START OUT
IN WEST-CENTRAL DURING THE DAY ON SUNDAY...THEN WORK TOWARDS THE
EAST SUNDAY NIGHT/EARLY MONDAY WITH PRECIP TAPERING FROM WEST TO
EAST THROUGH THE DAY ON MONDAY. EXPECT A QUIET PERIOD ON TUESDAY
AS FAST MOVING RIDGE PASSES OVER BEHIND DEPARTING SYSTEM BEFORE
SOUTHWESTERLY FLOW SETS UP OVER THE AREA. MODELS DIFFER SOME ON
HOW STRONG THIS FLOW IS...BUT THE MAIN POINT IS THAT THIS WILL
BRING THE NEXT ROUND OF PRECIPITATION CHANCES TO THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 915 AM CDT SAT AUG 16 2014
WIDESPREAD MVFR CIGS AND VIS WITH LCL IFR VIS IN HEAVIER PRECIP WILL
CONTINUE THROUGH THIS MORNING OVER MUCH OF NORTHWEST INTO PARTS OF
SOUTH CENTRAL NORTH DAKOTA AS SHRA/TSRA CONTINUE TO MOVE THROUGH
THE AREA. PRECIPITATION WILL SLOWLY DEVELOP TOWARDS THE EAST TODAY
POSSIBLY BRINGING VISIBILITY RESTRICTIONS FURTHER INTO CENTRAL
NORTH DAKOTA. AREAS OF FOG WILL ALSO BRING VISIBILITY RESTRICTIONS
OVER PARTS OF CENTRAL AND EASTERN NORTH DAKOTA EARLY THIS MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...JPM
LONG TERM...JJS
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
100 AM CDT SAT AUG 16 2014
.UPDATE...
ISSUED AT 1243 AM CDT SAT AUG 16 2014
HAVE UPGRADED...MORE SIGNIFICANT...THE THREE FLOOD ADVISORIES INTO
ONE OVERLAND FLOOD WARNING FOR THE CENTRAL PART OF WESTERN NORTH
DAKOTA. HAVE ALSO CANCELED THE FLASH FLOOD WATCH AS FLOODING IS
NOT OF THE FLASH VARIETY AND WILL NOT BE THE REST OF THE NIGHT.
UPDATE ISSUED AT 954 PM CDT FRI AUG 15 2014
AN UPPER LEVEL MESO-LOW CONTINUES TO GENERATE MODERATE RAINFALL
ACROSS WEST-CENTRAL NORTH DAKOTA. RAINFALL AMOUNTS UNDER THE
HIGHEST REFLECTIVITIES HAVE TOTALED GENERALLY BETWEEN 1 AND 2
INCHES NEAR GRASSY BUTTE AND FAIRFIELD. OUTFLOW FROM
THUNDERSTORMS OVER NORTHEASTERN MONTANA IS RACING SOUTHEASTWARD
TOWARDS THIS AREA OF PERSISTENT RAIN SHOWERS...AND WILL LIKELY
ENHANCE LIFT AND RAINFALL INTENSITY DURING THE NEXT FEW HOURS. AS
A RESULT...WILL MAINTAIN THE FLASH FLOOD WATCH FOR THIS UPDATE.
FOCUS THEN SHIFTS UPSTREAM WHERE A LARGER SHORTWAVE IS GENERATING
A LINE OF THUNDERSTORMS ACROSS CENTRAL MONTANA. BASED ON ITS
CURRENT TRAJECTORY...THESE THUNDERSTORMS SHOULD CROSS INTO EXTREME
WESTERN NORTH DAKOTA AROUND 10Z. ALTHOUGH IT IS FORECAST TO BRING
ADDITIONAL RAINFALL WEST...IT SHOULD KICK THE MESO-LOW OUT OF
WEST-CENTRAL NORTH DAKOTA INTO SOUTH DAKOTA.
UPDATED THE SENSIBLE WEATHER ELEMENTS BASED ON CURRENT OBS/TRENDS.
THE UPDATED PRODUCTS WILL BE OUT SHORTLY.
UPDATE ISSUED AT 556 PM CDT FRI AUG 15 2014
THE LATEST MODEL GUIDANCE CONTINUES TO PROG THE HEAVY RAIN
POTENTIAL CONTINUING OVER SOUTHWESTERN NORTH DAKOTA TONIGHT. MOST
MODELS ARE A LITTLE TOO FAR SOUTH WITH THE ONGOING ACTIVITY...WITH
THE 12Z GEM ACTUALLY DOING A PRETTY GOOD JOB PAINTING THE HIGHEST
QPF WHERE THE CURRENT CONVECTION IS LOCATED.
FOR THE UPDATE...ADJUSTED POPS UPWARDS BASED ON CURRENT RADAR OBS
AND EXTRAPOLATED THE HIGHER POPS SOUTHEASTWARD THROUGH THE
OVERNIGHT HOURS...BASED ON THE 12Z GEM SOLUTION. WILL KEEP THE
CURRENT FLASH FLOOD WATCH AS IS FOR THIS UPDATE.
ALSO EXTENDED THE FLOOD ADVISORY FOR BILLINGS...SOUTHWESTERN
MCKENZIE...AND GOLDEN VALLEY COUNTIES UNTIL 530 AM CDT. THE LATEST
RAINFALL REPORT FROM BEACH IS 4.6 INCHES...AND IT IS STILL
RAINING. OVERLAND FLOODING CONTINUES TO BE AN ISSUE WITH SOME
COUNTY ROADS UNDER WATER.
THE UPDATED GRIDDED AND TEXT PRODUCTS WILL BE OUT SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 549 PM CDT FRI AUG 15 2014
HEAVY RAINFALL AND ASSOCIATED FLASH FLOODING WILL HIGHLIGHT THE
SHORT TERM FORECAST.
EXTENDED THE FLASH FLOOD WATCH THROUGH 12 UTC SATURDAY ACROSS THE
SOUTHWEST. THE 12 UTC WRF-ARW/NMM...INCOMING 18 UTC NAM AND 16-17
UTC HRRR ITERATIONS CONTINUE TO FOCUS RAIN SHOWERS AND
THUNDERSTORMS WITH PROLONGED MODERATE TO HEAVY RAINFALL ACROSS THE
SOUTHWEST AND FAR SOUTH CENTRAL LATE THIS AFTERNOON AND INTO THE
EARLY EVENING IN ASSOCIATION WITH THE UPPER LEVEL LOW EVIDENT ON
WATER VAPOR ACROSS THE SOUTHWEST. THESE SOLUTIONS WANE CONVECTION
A BIT AFTER SUNSET...THEN REDEVELOP THUNDERSTORMS ACROSS THE WEST
REINVIGORATED BY INCREASING UPPER LEVEL DIFFLUENCE AND IMPULSES
EJECTING OUT OF THE PACIFIC NORTHWEST CLOSED LOW. THIS IS IN
AGREEMENT WITH NESDIS SATELLITE PRECIPITATION ESTIMATES AND
HIGHLIGHTS FOR HEAVY RAINFALL TONIGHT. GIVEN THIS REGENERATION OF
SLOW MOVING STORMS LATE TONIGHT OVER ALREADY SATURATED AREAS WITH
PWATS NEAR 1.75 INCHES...THE EXTENSION OF THE WATCH IS WARRANTIED.
THE 12 UTC WRF-ARW/NMM DO HIGHLIGHT SIOUX AND EMMONS COUNTIES LATE
TONIGHT AS WELL FOR HEAVY RAIN...AND THIS WILL HAVE TO BE
MONITORED. ADDITIONAL SCATTERED THUNDERSTORMS WITH HEAVY RAIN WILL
CONTINUE ACROSS MUCH OF THE AREA SATURDAY AS THE PACIFIC NORTHWEST
UPPER LEVEL LOW BEGINS TO PROPAGATE INTO THE NORTHERN PLAINS. WILL
ALLOW FURTHER SHIFTS TO EVALUATE IF A FLASH FLOOD WATCH IS NEEDED.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 549 PM CDT FRI AUG 15 2014
THE MAIN FORECAST ISSUE IN THE EXTENDED PERIOD WILL CONTINUE TO BE
THE THREAT OF HEAVY RAINFALL THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK. DETERMINISTIC MODELS ARE IN REASONABLE AGREEMENT IN BRINGING
AN UPPER LEVEL LOW CURRENTLY OVER EASTERN WASHINGTON...EAST ALONG
THE INTERNATIONAL BORDER...TO THE EASTERN DAKOTAS BY MONDAY
AFTERNOON. ALTHOUGH THE THREAT OF SEVERE WEATHER WILL BE LOW. WE
WILL STILL NEED TO MONITOR THE THREAT OF HEAVY RAINFALL...
PARTICULARLY IN THE SUNDAY NIGHT INTO EARLY MONDAY PERIOD.
PERHAPS A BRIEF DRY PERIOD TUESDAY INTO EARLY WEDNESDAY. BUT MODELS
THEN START SHIFTING INTO MORE OF A SOUTHWEST FLOW BY MID TO LATE
WEEK BRINGING INCREASED PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1243 AM CDT SAT AUG 16 2014
WIDESPREAD MVFR CIGS AND VIS WITH LCL IFR VIS IN HEAVIER PRECIP WILL
CONTINUE THROUGH THIS MORNING OVER MUCH OF WESTERN NORTH DAKOTA AS
SHRA/TSRA CONTINUE TO MOVE THROUGH THE AREA. PRECIPITATION WILL
SLOWLY DEVELOP TOWARDS THE EAST TODAY POSSIBLY BRINGING VISIBILITY
RESTRICTIONS INTO CENTRAL NORTH DAKOTA.
&&
.HYDROLOGY...
ISSUED AT 1243 AM CDT SAT AUG 16 2014
IN THE AREA FROM DICKINSON...TO JUST SOUTH OF WILLISTON...OVERLAND
FLOODING CONTINUES AND HAS WORSENED AS YARDS AND FIELDS HAD
STANDING WATER...AND NOW SOME SMALLER CREEKS WERE OVERFLOWING
THEIR BANKS IN DUNN AND STARK COUNTIES. TRAVEL ALERTS HAVE BEEN
ISSUED BY COUNTY OFFICIALS AND ROAD RESTRICTIONS HAVE BEEN PLACED
ON WITH RESPECT TO WEIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...JJS
HYDROLOGY...JPM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1146 PM CDT FRI AUG 15 2014
.UPDATE...
ISSUED AT 1145 PM CDT FRI AUG 15 2014
ISOLATED STORMS CONTINUE TO FIRE ALONG A FRONTAL BOUNDARY MOVING
SLOWLY THROUGH THE NORTHERN COUNTIES. RAP SEEMS TO HAVE A PRETTY
GOOD HANDLE ON CURRENT CONVECTION...SO CONTINUED THE TREND OF SOME
ISOLATED ACTIVITY THROUGH THE NEXT FEW HOURS...BUT THE MAIN SHOW
WILL BE LATER TOMORROW AS THE WEAK UPPER SYSTEM MOVES
SOUTHEASTWARD OUT OF WESTERN ND.
UPDATE ISSUED AT 946 PM CDT FRI AUG 15 2014
STORMS MOVING INTO PEMBINA COUNTY A FEW HOURS AGO DISSIPATED...BUT
MORE CONVECTION JUST NORTH OF THE CANADIAN BORDER WILL CONTINUE TO
MOVE DOWN INTO THE FORECAST AREA. BUMPED UP POPS FOR A WHILE IN
THE NORTHERN RED RIVER VALLEY...BUT DID NOT GO TOO HIGH AS THERE
CONTINUES TO BE A DECREASING TREND. THERE IS A DECENT AMOUNT OF
ELEVATED CAPE BUT SHEAR IS LACKING SO DO NOT THINK ANYTHING WILL
BE SEVERE. SHORT RANGE MODELS HAVE PRECIP MOVING TOWARDS GFK BY
06Z BUT SEEM TO BE OVERDOING CURRENT CONVECTION SO WILL JUST KEEP
LOW POPS AND AN EYE ON IT FOR NOW.
UPDATE ISSUED AT 653 PM CDT FRI AUG 15 2014
ADJUSTED POPS FOR THIS EVENING AS THE RAIN OVER WESTERN ND DOES
NOT APPEAR TO BE MOVING ANY FURTHER EAST. BEST CHANCES FOR
ISOLATED STORMS WILL CONTINUE TO BE IN THE NORTHERN CWA AS A COLD
FRONT COMES DOWN. THINK THAT THE SOUTH WILL STAY DRY UNTIL THE
EARLY MORNING HOURS. WILL CONTINUE TO KEEP LOWS IN THE 60S.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 300 PM CDT FRI AUG 15 2014
THUNDER CHANCES WILL BE THE MAIN CHALLENGE. THIS FA WILL BE
BETWEEN AN UPPER CIRCULATION TO THE WEST AND ANOTHER UPPER WAVE TO
THE EAST...AND MOST AREAS SHOULD REMAIN DRY. HOWEVER...THERE WILL
BE CHANCES FOR ISOLD/SCATTERED ACTIVITY.
FOR THE REMAINDER OF THIS AFTERNOON INTO THE EVENING...THE
AIRMASS HAS BECOME UNSTABLE...WITH MLCAPE 1500-2000 J/KG ALONG AND
WEST OF THE VALLEY. CURRENT LAPS ANALYSIS INDICATES MLCIN 10-20
J/KG...AND NOT SURE THERE WILL BE ENOUGH HEATING/FORCING FOR ANY
THUNDER DEVELOPMENT. THE BEST CHANCE FOR ISOLD ACTIVITY WILL
LIKELY BE THIS EVENING NEAR THE INTERNATIONAL BORDER AS THE COLD
FRONT (ASSOCIATED WITH THE UPPER WAVE TO THE EAST) PROPAGATES
SOUTHWARD.
THE NEXT BEST CHANCE FOR PRECIP WILL BE ACROSS THE SOUTHERN FA ON
SATURDAY AS THE UPPER CIRCULATION ACROSS SOUTHWESTERN NORTH DAKOTA
PROPAGATES TO THE SOUTHEAST. DEEP LAYER SHEAR WILL BE VERY
WEAK...AND DO NOT EXPECT ANY STRONG STORMS (ALTHOUGH THE STORM
MOTIONS ARE EXPECTED TO BE RELATIVELY SLOW AND LOCALLY HEAVY
RAINFALL MAY BE POSSIBLE).
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 300 PM CDT FRI AUG 15 2014
SUNDAY-MONDAY...MUCH OF SUNDAY WILL BE DRY. THEN...THE UPPER LOW
ACROSS THE PAC NW WILL PROPAGATE THROUGH THE REGION SUNDAY NIGHT
INTO MONDAY. THIS WILL LEAD TO A HIGHER PROBABILITY THAT MOST
PLACES WILL EXPERIENCE MEASURABLE PRECIPITATION. CURRENT MODELS
RUNS ARE RELATIVELY WEAK WITH DEEP LAYER SHEAR AND
INSTABILITY...AND THE SEVERE THREAT WOULD APPEAR TO BE TOWARD THE
LOWER END.
MONDAY NIGHT-FRIDAY...THIS PARTICULAR SUITE OF THE VARIOUS MODELS
ARE IN FAIR AGREEMENT. A DEPARTING UPPER LOW WITH ATTENDANT
SURFACE REFLECTION SHOULD BRING AN END TO PRECIPITATION BY TUESDAY
AFTERNOON. AS LOW MOVES TO THE EAST EXPECT A BROAD TROUGH TO FORM
OVER THE NORTHWEST U.S. THIS SHOULD HELP SPLIT THE FLOW OVER THE
CWFA MID WEEK.
BASED ON THE BRIEF SPLIT FLOW THAT FORMS...THE BULK OF WEDNESDAY
SHOULD BE PRECIPITATION FREE. WAA DRIVEN TSRA BEGIN TO MOVE INTO THE
WESTERN HALF OF THE CWFA AFTER 00Z THU AND OVERSPREAD THE REGION
LINGERING INTO FRIDAY.
TEMPERATURES SHOULD GENERALLY BE NEAR MID AUGUST MEDIANS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1145 PM CDT FRI AUG 15 2014
VFR CONDITIONS WILL CONTINUE...ALTHOUGH KBJI MAY DROP DOWN TO MVFR
FOR A BRIEF PERIOD DURING THE MORNING. WINDS WILL SHIFT AROUND TO
THE NORTH AS A COLD FRONT COMES DOWN INTO THE AREA. THINK THAT
CIGS WILL BE MOSTLY 4000-6000 FT BEHIND THE FRONT BUT WILL HAVE TO
KEEP AN EYE OUT FOR SOME MVFR. BY AFTERNOON...CIRRUS WILL BE THE
MAIN CLOUD COVER AND SOME CONVECTION WILL BE POSSIBLE OVER THE
SOUTHERN AND WESTERN FORECAST AREA AS AN UPPER LEVEL DISTURBANCE
MOVES SOUTH. TOO SOON TO TELL IF IT WILL IMPACT KFAR OR ANY OF THE
OTHER TAF SITES...SO WILL LEAVE CONVECTION OUT FOR NOT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...EWENS/TG
AVIATION...JR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
726 PM EDT SUN AUG 17 2014
.SYNOPSIS...
A WEAK LOW PRESSURE SYSTEM OVER SOUTHERN INDIANA WILL BEGIN TO
ACCELERATE A LITTLE AS IT CONTINUES TO WEAKEN FURTHER WHILE MOVING
ALONG AND JUST SOUTH OF THE OHIO RIVER. SHOWERS AND THUNDERSTORMS
WILL GENERALLY STAY FOCUSED SOUTH OF THE OHIO RIVER TONIGHT AND
MONDAY NEAR THE PATH OF THE LOW...THOUGH SCATTERED SHOWERS AND
STORMS WILL BE POSSIBLE OVER CENTRAL AND SOUTHERN OHIO AND INDIANA
AS WELL IN THE VERY HUMID AND MODERATELY UNSTABLE AIRMASS. A BRIEF
PERIOD DRY WEATHER IS EXPECTED MONDAY NIGHT INTO EARLY TUESDAY
BEFORE THE NEXT WEAK COLD FRONT APPROACHES THE REGION WITH A
THREAT FOR SHOWERS AND THUNDERSTORMS. THIS FRONT WILL WASH OUT AND
STALL OVER THE AREA...WITH A WARM AND VERY HUMID AIRMASS TAKING
HOLD FOR THE LAST HALF OF THE WEEK INTO EARLY NEXT WEEKEND...WITH
HIGHS WELL INTO THE 80S AND MILD NIGHTS IN THE 60S AND LOWER 70S.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THIS AFTERNOON OBJECTIVE RAP ANALYSIS AND OBSERVATIONAL DATA SETS
/SATELLITE AND RADAR LOOPS/ CONFIRM THE WEAKENING MID LEVEL CLOSED
LOW NEARLY STATIONARY OVER SOUTHWESTERN INDIANA. A WEAK COLD FRONT
HAD ALSO STALLED ACROSS NORTHERN OHIO. RADAR TRENDS OVER THE LAST
FEW HOURS SHOW THAT THE BULK OF STRONG FORCING/DEEPER MOISTURE
RESIDED ON THE SRN/SERN FLANK OF THE UPPER LOW...WITH WIDESPREAD
SHOWERS AND THUNDERSTORMS OVER KY/TN. THE NERN FLANK OF A SHIELD
OF LGT/MOD SHOWERS/RAIN HAS STUBBORNLY BEEN ERODED AS IT MAKES
INROADS INTO THE WFO ILN FORECAST AREA. SCT SHRA/TSRA WERE SLOWLY
DEVELOPING ALONG THE STALLED FRONT OVER NORTHERN OHIO.
MESOANALYSIS LATE THIS AFTERNOON INDICATED A PLUME OF HIGH PWAT
REMAINED ATTENDANT TO THE UPPER LOW...WITH PWAT ABOUT 160% OF
NORMAL OVER SRN IND/NRN KY NEAR AND JUST EAST OF THE CENTER OF
CIRCULATION. A LARGE RESERVOIR OF MID 60S TO MID 70S SURFACE
DEWPOINTS EXISTED NEAR THE CIRCULATION AND ESPECIALLY TO THE
SOUTH/WEST. INSTBY WAS RATHER MEAGER OWING TO MOIST LAPSE RATES
AND AMPLE/WIDESPREAD CLOUDS OVER MUCH OF THE AREA...KEEPING
TEMPERATURES IN THE 70S FOR THE MOST PART. ALSO OF IMPORTANCE TO
THE SHORT TERM FORECAST IS A STRONG SHORTWAVE TROUGH ACROSS SASK
MOVING EAST.
TONIGHT...THERE IS STRONG AGREEMENT AMONG 17.12Z DATA THAT THE
WEAKENING CLOSED LOW WILL CONTINUE TO SLOWLY WEAKEN AND BECOME A
LITTLE MORE PROGRESSIVE AS IT OPENS UP AND SHEARS DOWNSTREAM A
BIT. THIS IS OWING TO THE KICKER ENERGY MOVING QUICKLY ACROSS SASK
ATOP THE SUBTROPICAL SWRN CONUS RIDGING. SPECIFICALLY...THE 700MB
CLOSED LOW WILL PLOD SLOWLY ALONG AND JUST SOUTH OF THE OHIO RIVER
THROUGH NORTHERN KENTUCKY REACHING THE CVG AREA BY SUNRISE MONDAY
MORNING. GIVEN THE BULK OF THE FLOW/FORCING WILL BE ON THE
SOUTH/SOUTHEAST SIDE OF THE CIRCULATION...EXPECT THE MOST
WIDESPREAD/HEAVIEST RAIN JUST SOUTH OF THE LOCAL FORECAST AREA.
HOWEVER...WILL NEED TO WATCH ANY ACTIVITY THAT FORMS ACROSS NRN KY
AS MID LVL STEERING FLOW WILL BE LIGHT NEAR THE PATH OF THE MID
LEVEL SYSTEM AND IF A DEFORMATION TYPE RAIN BAND FORMS ACRS OUR
NRN KY COUNTIES THE PWAT/WARM RAIN PROCESSES COULD LEAD TO NARROW
BAND OF HEAVIER RAIN...BUT RIGHT NOW IT SEEMS THE WEAKENING NATURE
OF THE OPENING WAVE AND THE IDEA IT BECOMES MORE PROGRESSIVE WITH
TIME SHOULD MITIGATE THIS POTENTIAL A GREAT DEGREE. MAINTAINED THE
LIKELY RAIN CHANCES ACROSS OUR FAR SOUTH NEAR THE NOSE OF MODEST
NORTHEAST-ORIENTED LOW LEVEL JET THAT POINTS INTO OUR AREA THIS
EVENING INTO THE FIRST PART OF THE OVERNIGHT...ALTHOUGH RECENT
EXPERIMENTAL /ESRL/ AND PARALLEL /NCEP/ HRRR RUNS ARE NOT VERY
BULLISH ON RAIN COVERAGE ACRS NRN KY TONIGHT. ELSEWHERE...AS THERE
HAS BEEN DURING THE DAY...SCT SHRA ON THE PERIPHERY OF THE UPPER
LOW WILL CON/T TO BE POSSIBLE...WITH ACTIVITY REMAINING LIGHT AND
LIKELY NOT CONTAINING THUNDER.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
THROUGH THE DAY MONDAY THE UPPER LEVEL WAVE REALLY OPENS
UP/SHEARS OUT/WEAKENS AS DEEPER LAYER NWLY FLOW DRIVING THE KICKER
ENERGY TO OUR NW SPREADS ACROSS THE GREAT LAKES. A SURFACE
TROUGH/INVERTED TROUGH HANGS BACK OVER THE FORECAST AREA IN THE
WAKE OF THE WEAKENING SURFACE LOW...AS DOES THE WEAK/WASHING OUT
STATIONARY FRONT OVER NORTHERN OHIO. A VERY MOIST AND UNCAPPED
AIRMASS REMAINS DURING PEAK HEATING WITH WIDESPREAD CUMULUS
EVENTUALLY CONVECTING DURING DAYTIME HEATING WITH THE SUBTLE
SURFACE FORCING MECHANISMS...AND MLCAPE PER 17.12Z FORECAST
SOUNDINGS /GFS AND NAM/ OF 1000-1500 J/KG. FLOW IS WEAK SO JUST
SOME SLOW MOVING HEAVY RAINERS ALL THAT IS EXPECTED DURING THE
AFTERNOON/EARLY EVENING. GIVEN THE AMPLE MOISTURE...AND NOTING
THIS REGION WEST OF THE UPPER LOW FAILED TO WARM MUCH TODAY...AM
KEEPING HIGHS MOSTLY IN THE 70S TO AROUND 80 ON MONDAY...ON THE
COOLER SIDE OF 17.12Z MOS.
ON TUESDAY...THE AFOREMENTIONED SHORTWAVE OVER SASK WILL BE
ARRIVING WITH A COLD FRONT AT PEAK HEATING WILL ACTUALLY ENCOUNTER
A SOMEWHAT FAVORABLE AIRMASS FOR ROBUST CONVECTION. BOUNDARY LAYER
FLOW WILL HAVE TURNED TO THE SOUTHWEST WHILE MID LEVEL WNWLY FLOW
WILL BE INCREASING AS RIDGING BEGINS TO BUILD A MODEST HEIGHT
GRADIENT TO OUR WEST/SOUTH. 17.12Z NAM/GFS FORECAST BUFR SOUNDINGS
FOR ILN/CVG/DAY/CMH ALL EXHIBIT MLCAPE FROM 1500 TO 2000 J/KG WITH
A STEEPER MID LEVEL LAPSE RATE WITH BOUNDARY LAYER DWPTS STILL IN
THE 60S. 0-6KM BULK SHEAR VALUES AROUND 30-35KTS COULD PROMOTE A
LITTLE MORE ORGANIZATION TO THE STORMS COMPARED TO MONDAY.
UPCOMING SHIFTS MAY NEED TO MOVE TO HIGHER RAIN CHANCES IF CURRENT
SIGNALS PERSIST..ESPECIALLY LATER IN THE DAY TUES INTO TUESDAY EVENING.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL RIDGE OVER THE GULF COAST REGION WILL BUILD SLOWLY NORTH
INTO THE MID MISSISSIPPI VALLEY THROUGH THE END OF THE WEEK. THIS
WILL RESULT IN A NORTHWEST FLOW PATTERN ALOFT THROUGH AT LEAST
FRIDAY. BOTH THE 12Z GFS AND 12Z ECMWF CONTINUE TO INDICATE THE
POSSIBILITY OF SEVERAL SHORT WAVES RIDING DOWN THROUGH THE AREA IN
THIS PATTERN. WITH DEWPOINTS PUSHING UP INTO THE UPPER 60S TO LOWER
70S...THERE SHOULD BE SUFFICIENT INSTABILITY TO CREATE THE POTENTIAL
FOR A RATHER ACTIVE PATTERN THROUGH THE END OF THE WEEK. TIMING
REMAINS DIFFICULT THOUGH SO WILL KEEP POPS IN THE CHANCE CATEGORY.
TEMPERATURES ALSO REMAIN SOMEWHAT PROBLEMATIC AS WE WILL REMAIN IN
THE TRANSITION ZONE BETWEEN WARMER TEMPERATURES TO OUR
SOUTHWEST/COOLER TO THE NORTHEAST. WILL CONTINUE WITH FAIRLY
SEASONABLE HIGHS...BUT OVERNIGHT LOWS MAY REMAIN A LITTLE ON THE
WARM SIDE...UPPER 60S TO NEAR 70...GIVEN THE HIGHER DEWPOINTS.
SOME UNCERTAINTY EXIST BETWEEN THE 12Z GFS AND 12Z ECMWF OVER THE
WEEKEND AS THE GFS IS TRYING TO BUILD THE UPPER LEVEL RIDGE MORE
EAST TOWARD OUR AREA...WHILE THE ECMWF BEGINS TO FLATTEN OUT THE
RIDGE AS SHORT WAVE ENERGY MOVES ACROSS THE UPPER GREAT LAKES. HAVE
TRENDED MORE TOWARD THE GFS...DECREASING POPS THROUGH THE WEEKEND
AND ALLOWING FOR A CONTINUED SLOW WARMUP IN TEMPS THROUGH SUNDAY.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
WEAK SFC LOW PRESSURE OVER EXTREME WESTERN KY WILL TRACK SLOWLY
EAST THRU KY OVERNIGHT INTO MONDAY. BEST MOISTURE AND LIFT CLOSER
TO THE SFC LOW BUT SOME BANDS OF SHOWERS AROUND THIS FEATURE MAY
AFFECT KCVG AND KLUK MAINLY THRU THE LATE EVENING.
VFR CEILINGS ARE EXPECTED TO DROP INTO THE MVFR CATEGORY WITH MVFR
VSBYS DUE TO FOG AT ALL SITES LKLY OVERNIGHT IN A MOIST BOUNDARY
LAYER. ADDITIONAL SHOWER ACTIVITY POSSIBLE MONDAY BUT CHANCES
DIMINISH AS THE SYSTEM MOVES EAST. CIGS/VSBYS EXPECTED TO IMP
IMPROVE MONDAY AFTERNOON AS THE LOW MOVES EAST.
WIND DIRECTION WILL VARY WITH RESPECT TO THE POSITION OF THE LOW
AND ARE GENERALLY EXPECTED TO BACK FROM SE TO NE OVERNIGHT AND
THEN NW MONDAY AFTN. WIND SPEEDS ARE EXPECTED TO REMAIN BELOW 10
KNOTS.
OUTLOOK...THUNDERSTORMS POSSIBLE TUESDAY THROUGH THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...JGL
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
355 PM EDT SAT AUG 16 2014
.SYNOPSIS...
A SLOW MOVING LOW PRESSURE SYSTEM OVER THE MID MISSISSIPPI VALLEY
SATURDAY EVENING WILL CONTINUE TO CREEP SLOWLY EASTWARD AS IT
SLOWLY WEAKENS. A PLUME OF UNSEASONABLY DEEP MOISTURE AHEAD OF THE
SYSTEM WILL CONTINUE TO SPREAD INTO AND THROUGH THE OHIO VALLEY
TONIGHT AND SUNDAY...AND THIS MOISTURE AND COMBINED WITH SUBTLE
DISTURBANCES AHEAD OF THE LOW WILL CONTINUE TO ALLOW SHOWERS TO
DEVELOP AT TIMES TONIGHT THROUGH SUNDAY IN SCATTERED FASHION. THE
SLOW MOVING LOW WILL MOVE INTO THE TRI STATE ON SUNDAY NIGHT AND
MONDAY...SHIFTING EAST OF THE AREA MONDAY NIGHT. THIS WILL BRING
SHOWERS AND A FEW THUNDERSTORMS...PRIMARILY TO AREAS ALONG AND
SOUTH OF THE OHIO RIVER...BUT ALL AREAS WILL SEE AT LEAST SOME
THREAT OF RAIN WITH THIS SYSTEM. IT WILL BE HUMID AND MILD DESPITE
AMPLE CLOUDS SUNDAY AND MONDAY. IN THE WAKE OF THIS SYSTEM ON
TUESDAY...AND CONTINUING THROUGH THE REST OF THE WORK WEEK...WILL
BE A WARM AND MUGGY AIRMASS WITH DAILY THREATS FOR SHOWERS AND
THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
GOES WATER VAPOR AND VISIBLE SATELLITE IMAGERY PLACE THE CENTER OF
THE WEAK CLOSED LOW OVER NORTHEAST MISSOURI THIS AFTERNOON. OUR
POOL OF UNSEASONABLY LOW DEWPTS /40S/ WHICH ALLOWED FOR SEVERAL
CHILLY NIGHTS WAS QUICKLY BEING REPLACED AN EQUALLY IMPRESSIVE
PLUME OF ABOVE NORMAL MOISTURE POISED JUST TO THE WEST...WHERE
RTMA DWPT ANALYSIS SHOWS WIDESPREAD MID 60S TO LOWER 70S DWPTS
NEAR AND AHEAD OF THE INBOUND CLOSED LOW.
THE 16.12Z RAOBS CLEARLY SHOWED THIS IMPRESSIVE MOISTURE
GRADIENT...WITH A 0.55" PWAT AT KILN TO A 1.82" PWAT AT KILX
/CENTRAL ILLINOIS/ WHICH IS ABOUT 1.5 STANDARD DEVIATIONS ABOVE
CLIMO...OR ABOUT 140% NORMAL.
LEADING EDGE MOISTURE TRANSPORT/THETA-E ADVECTION IS RESPONSIBLE
FOR A WEAKENING AREA OF SPRINKLES/VERY LIGHT SHOWERS ALONG AND
NORTH OF I-70 TODAY AND THIS WILL CONTINUE TO PETER OUT AS OUTRUNS
THE BETTER MOISTURE TO THE WEST. SO CARRYING SMALL CHANCES OF RAIN
LATE AFTERNOON/EARLY EVENING ALONG THIS AXIS AS MANY SITES HAVE
NOT BEEN MEASURING WITH THE SPRINKLES.
INTO THE EVENING AND OVERNIGHT AS THE LOW CREEPS SLOWLY
EASTWARD...SUBTLE MID LEVEL ENERGY SHEARING DOWNSTREAM FROM THE
WOBBLY CLOSED LOW WILL INDUCE MORE SCT SHRA AND A FEW STORMS.
LOCATION IS STILL VERY MUCH IN QUESTION GIVEN LACK OF APPRECIABLE
LOW LEVEL FORCING. RECENT HRRR RUNS /EXPERIMENTAL ESRL AND
PARALLEL NCEP/ HAVE BEEN ATTEMPTING TO FOCUS LIGHT/MOD RAIN
SHOWERS NEAR AND SOUTH OF THE OHIO RIVER CLOSER TO NOSE OF MODEST
LOW LEVEL JET POINTING INTO SRN IND. 16.12Z ECMWF ALSO FAVORING
THE SOUTH AS IS 16.12Z GFS WITH SCT SHRA. HOWEVER 16.12Z NCEP-
BASED ARW-WRF...NMM-WRF...AND SREF PROBABILITIES SEEM TO BE
LATCHING ONTO MORE OF A WEAK S/W DRIVEN RAIN CHANCE NORTH OF THE
OHIO RIVER. THERE/S SOME SUPPORT FOR BOTH...SO AM NOT GOING TO TRY
AND GET CUTE AND WILL INDICATE BROAD/MODERATE THREAT OF SHOWERS
TONIGHT OVER MOST AREAS. ACTIVITY EITHER WAY WON/T BE
WIDESPREAD...AND THUNDER THREATS SEEM RATHER LOW GIVEN STILL-
ARRIVING INSTBY ALOFT. GIVEN THE HUGE INCREASE IN MOISTURE THAT IS
OCCURRING...LOWS TONIGHT ABOUT 15 DEGREES HIGHER THAN LAST NIGHT.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
THE WEAK CLOSED LOW DRIFTING SOUTHEAST THROUGH THE MID MISSISSIPPI
VALLEY WILL BEGIN TO WEAKEN FURTHER AND SHEAR EASTWARD MORE
QUICKLY BEGINNING SUNDAY INTO SUNDAY NIGHT. THIS PROCESS STILL
KEEPS THE BULK OF THE FORCING WEST /ESPECIALLY SOUTHWEST/ OF THE
ILN FORECAST AREA ON SUNDAY...WHILE A COLD FRONT THAT HAS DROPPED
INTO NRN OHIO ATTENDANT TO ENERGY DIVING THROUGH SERN CANADA COMES
TO A HALT. BUT TROPOSPHERIC MOISTURE WILL CONTINUE TO BUILD WITH
PWATS EXCEEDING 1.75" ACROSS THE SOUTHERN FORECAST AREA. AREAS OF
SHOWERS WILL STILL BE POSSIBLE ACROSS THE AREA IN THE WEAKLY
FORCED REGION DOWNSTREAM OF THE WEAK CLOSED LOW...BUT DON/T SEE
MORE ORGANIZED ACTIVITY PUSHING INTO THE SOUTHERN/WESTERN AREAS
UNTIL EARLY SUNDAY EVENING OR INTO SUNDAY NIGHT. FLOW IS PRETTY
WEAK OVERALL SO NOT EXPECTING ANY THREAT OF SEVERE...BUT
INDIVIDUAL CORES WILL BE SLOW MOVING AND WITH THE AMPLE MOISTURE
THERE COULD BE SOME LOCALIZED HEAVY RAIN LATER SUNDAY NIGHT INTO
MONDAY IN OUR SOUTH. THINK OVERALL THIS THREAT IS LOWER THAN WHAT
PREVIOUS GUIDANCE HAD INDICATED...AS MODELS HAVE TRENDED
FASTER/WEAKER/MORE SHEARED WITH THE CLOSE LOW AS IT SHIFTS ACROSS
KENTUCKY AND OPENS UP AND BECOMES MORE PROGRESSIVE. NOTICED WPC
STILL KEEPS FAR SOUTHERN AREAS IN SLGT RISK FOR FLASH FLOOD
EXCEEDING RAINS...SO WILL KEEP THIS IN THE HAZ WX OUTLOOK BUT
REFINE THE THREAT AREA TO CLOSER TO THE TRACK OF MID LEVEL
CIRCULATION WHERE POTENTIAL FOR REGENERATION ALONG THE MAJOR AXIS
OF SHOWER/STORM POTENTIAL IS GREATEST. AMPLE CLOUDS AGAIN EXPECTED
SUNDAY INTO MONDAY SHOULD KEEP HIGHS IN CHECK FOR THE MOST
PART...70S TO LOWER 80S...IN WHAT WILL BE QUITE A HUMID AIRMASS.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
UPPER LEVEL RIDGING WILL BUILD FROM THE GULF COAST UP INTO THE
CENTRAL PLAINS THROUGH THE END OF THE WEEK. THIS WILL KEEP THE MID
OHIO VALLEY IN NORTHWEST FLOW ALOFT THROUGH MID TO LATE WEEK BEFORE
POSSIBLY TRANSITIONING TO MORE OF A NORTHERLY FLOW PATTERN ALOFT
HEADING INTO NEXT WEEKEND. A SERIES OF MID LEVEL SHORTWAVES ARE
FORECAST TO DROP DOWN THROUGH THE REGION THROUGH MUCH OF THE LONG
TERM PERIOD. THIS WILL RESULT IN A CONTINUED CHANCE OF
SHOWERS/THUNDERSTORMS THROUGH THE WEEK. HOWEVER...THE MODELS TEND TO
STRUGGLE WITH THE TIMING/PLACEMENT OF SHORT WAVES IN THIS KIND OF A
PATTERN. WILL THEREFORE GENERALLY JUST KEEP POPS IN THE CHANCE
CATEGORY WITH A BIT OF A DIURNAL ENHANCEMENT TO THEM. GIVEN THE
NORTHWEST FLOW PATTERN...EXPECT SOMEWHAT OF A NORTHEAST TO SOUTHWEST
TEMPERATURE GRADIENT ACROSS THE AREA THROUGH THE WEEK BUT OVERALL
TEMPERATURES SHOULD BE FAIRLY SEASONABLE.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED TO PERSIST. HOWEVER...MOISTURE
IS INCREASING IN A SOUTHWEST FLOW WELL AHEAD OF LOW PRESSURE
NEARING THE MISSISSIPPI RIVER. THE MOISTURE IS BEING
ISENTROPICALLY LIFTED IN THE VICINITY OF A WEAK WARM FRONTAL
BOUNDARY TO PRODUCE A FEW SHOWERS. IT APPEARS THAT DAY WILL BE
MOST AFFECTED BY THE SHOWERS THIS AFTERNOON. MODELS INDICATE
SCATTERED SHOWERS WILL PERSIST TONIGHT AS THE AIRMASS GROWS EVEN MORE
HUMID...AND BR MAY REDUCE VISIBILITIES TO MVFR AT LUK AND ILN.
FOR SUNDAY...MORE SHOWERS WILL BE POSSIBLE AT CVG AND LUK AS
FORCING WINDS UP AHEAD OF THE APPROACHING LOW. WINDS WILL BE OUT
OF THE SOUTHWEST AROUND 10 KNOTS TODAY...SHIFTING TO SOUTH ON SUNDAY.
OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY NIGHT THROUGH WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BINAU
NEAR TERM...BINAU
SHORT TERM...BINAU
LONG TERM...JGL
AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS NORMAN OK
1055 PM CDT SUN AUG 17 2014
.AVIATION...
18/06Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE PD. SOME HI
RES MODELS SHOW TSTMS OVER KS POSSIBLY REACHING NRN OK BEFORE DSPTG
WHICH COULD AFFECT KPNC. HOWEVER...MOST OTHER SOLUTIONS DO NOT SHOW THIS
SO WILL NOT INCLUDE ANY TSRA THERE IN THIS FCST.
&&
.PREV DISCUSSION... /ISSUED 926 PM CDT SUN AUG 17 2014/
.UPDATE...
PRECIP/WX...TEMPS...
&&
.DISCUSSION...
CLEANED UP POPS FOR THIS EVENING/OVERNIGHT... AS ACTIVITY HAS
SETTLED DOWN... NOT MUCH TO SEE ACROSS WRN OK/WRN N TX AT THE
MOMENT BUT SOME BATS TAKING FLIGHT. WITH THAT SAID... CONTINUE TO
KEEP AN EYE ON THE EVOLVING CONVECTION ACROSS S CENTRAL NE AND
INTO NRN/WRN KS. THE RECENT RUNS OF THE HRRR CONTINUE TO EXPAND
CONVECTION ALONG THE SFC BOUNDARY... PUSHING INTO NRN OK/CENTRAL
OK BY MON MORNING. DOUBTS ARE HEAVY WITH THIS SOLUTION... AS THIS
IS THE MOST AGGRESSIVE AND AN OUTLIER WHEN COMPARED TO OTHERS.
OVERALL... CONDITIONS FOR AN AGGRESSIVE BUILDING OF CONVECTION
SWRD ARE LACKING CONSIDERING THE WEAK LLJ PROGGED OVERNIGHT ACROSS
THE SRN PLAINS. WITH THAT SAID... WE WILL KEEP MULING OVER THE
DATA... BUT CONDITIONS OVERNIGHT LOOK FAIRLY QUIET AT THE MOMENT.
JTK
&&
.PREV DISCUSSION... /ISSUED 605 PM CDT SUN AUG 17 2014/
AVIATION...
18/00Z TAFS...VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH
THE PERIOD.
PREV DISCUSSION... /ISSUED 229 PM CDT SUN AUG 17 2014/
DISCUSSION...
WEAK DISTURBANCE AND RESIDUAL MCV INFLUENCE CONT TO AFFECT
SOUTHERN OKLAHOMA TODAY AND THIS WILL BE THE LOCATION MOST LIKELY
TO SEE SOME EARLY EVENING STORMS. HOWEVER WITH A FEW WEAK SFC
BOUNDARIES AND SOME RESIDUAL MID LEVEL MOISTURE COULD SEE ISOLATED
STORMS THIS EVENING NORTH INTO PARTS OF CENTRAL AND WESTERN
OKLAHOMA. WILL KEEP A MENTION OF ISOLATED STORMS UNTIL AROUND
SUNDOWN. OTHERWISE... ABOUT THE ONLY CHANCE FOR PRECIP MAY RESIDE
ACROSS FAR NORTHERN OKLAHOMA LATE MONDAY AND MONDAY NIGHT AS
ANOTHER WAVE MAKES ITS WAY ACROSS KANSAS. HAVE REINTRODUCED SOME
LOW POPS ACROSS NORTHERN OKLAHOMA MONDAY EVENING.
BEYOND MONDAY... MUCH OF THE WEEK WE WILL BE UNDER THE INFLUENCE
OF MID LEVEL RIDGE THAT BUILDS NORTHWEST FROM THE GULF COAST. THIS
WILL KEEP THE AREA DRY AND HOT. CURRENTLY... DO NOT ANTICIPATE THE
NEED FOR HEAT ADVISORY AS WE CONT TO DRY THINGS OUT THE AFTN HEAT
INDICES SHOULD GRADUALLY DECLINE EVEN WITH SIMILAR DAY-TO-DAY
TEMPS. HIGHEST HEAT INDICES WILL OCCUR MONDAY AND TUESDAY WITH
SOME AREAS NEAR 105 DURING THE AFTN HOURS.
MEDIUM RANGE MODELS DO HOWEVER TRY AND KNOCK THIS RIDGE BACK
SOUTH BY NEXT WEEKEND AS STRONGER TROUGH TAKES SHAPE TO THE WEST.
THIS MAY RESULT IN A BETTER CHANCE FOR A SFC FRONT TO APPROACH THE
AREA BYE THE END OF NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 96 72 99 73 / 10 10 10 10
HOBART OK 99 72 101 70 / 10 10 10 10
WICHITA FALLS TX 99 73 101 74 / 10 10 10 10
GAGE OK 100 68 100 69 / 10 10 10 10
PONCA CITY OK 93 71 98 73 / 10 10 10 20
DURANT OK 91 72 98 74 / 60 20 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
04/02
AREA FORECAST DISCUSSION
NWS NORMAN OK
926 PM CDT SUN AUG 17 2014
.UPDATE...
PRECIP/WX...TEMPS...
&&
.DISCUSSION...
CLEANED UP POPS FOR THIS EVENING/OVERNIGHT... AS ACTIVITY HAS
SETTLED DOWN... NOT MUCH TO SEE ACROSS WRN OK/WRN N TX AT THE
MOMENT BUT SOME BATS TAKING FLIGHT. WITH THAT SAID... CONTINUE TO
KEEP AN EYE ON THE EVOLVING CONVECTION ACROSS S CENTRAL NE AND
INTO NRN/WRN KS. THE RECENT RUNS OF THE HRRR CONTINUE TO EXPAND
CONVECTION ALONG THE SFC BOUNDARY... PUSHING INTO NRN OK/CENTRAL
OK BY MON MORNING. DOUBTS ARE HEAVY WITH THIS SOLUTION... AS THIS
IS THE MOST AGGRESSIVE AND AN OUTLIER WHEN COMPARED TO OTHERS.
OVERALL... CONDITIONS FOR AN AGGRESSIVE BUILDING OF CONVECTION
SWRD ARE LACKING CONSIDERING THE WEAK LLJ PROGGED OVERNIGHT ACROSS
THE SRN PLAINS. WITH THAT SAID... WE WILL KEEP MULING OVER THE
DATA... BUT CONDITIONS OVERNIGHT LOOK FAIRLY QUIET AT THE MOMENT.
JTK
&&
.PREV DISCUSSION... /ISSUED 605 PM CDT SUN AUG 17 2014/
AVIATION...
18/00Z TAFS...VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH
THE PERIOD.
PREV DISCUSSION... /ISSUED 229 PM CDT SUN AUG 17 2014/
DISCUSSION...
WEAK DISTURBANCE AND RESIDUAL MCV INFLUENCE CONT TO AFFECT
SOUTHERN OKLAHOMA TODAY AND THIS WILL BE THE LOCATION MOST LIKELY
TO SEE SOME EARLY EVENING STORMS. HOWEVER WITH A FEW WEAK SFC
BOUNDARIES AND SOME RESIDUAL MID LEVEL MOISTURE COULD SEE ISOLATED
STORMS THIS EVENING NORTH INTO PARTS OF CENTRAL AND WESTERN
OKLAHOMA. WILL KEEP A MENTION OF ISOLATED STORMS UNTIL AROUND
SUNDOWN. OTHERWISE... ABOUT THE ONLY CHANCE FOR PRECIP MAY RESIDE
ACROSS FAR NORTHERN OKLAHOMA LATE MONDAY AND MONDAY NIGHT AS
ANOTHER WAVE MAKES ITS WAY ACROSS KANSAS. HAVE REINTRODUCED SOME
LOW POPS ACROSS NORTHERN OKLAHOMA MONDAY EVENING.
BEYOND MONDAY... MUCH OF THE WEEK WE WILL BE UNDER THE INFLUENCE
OF MID LEVEL RIDGE THAT BUILDS NORTHWEST FROM THE GULF COAST. THIS
WILL KEEP THE AREA DRY AND HOT. CURRENTLY... DO NOT ANTICIPATE THE
NEED FOR HEAT ADVISORY AS WE CONT TO DRY THINGS OUT THE AFTN HEAT
INDICES SHOULD GRADUALLY DECLINE EVEN WITH SIMILAR DAY-TO-DAY
TEMPS. HIGHEST HEAT INDICES WILL OCCUR MONDAY AND TUESDAY WITH
SOME AREAS NEAR 105 DURING THE AFTN HOURS.
MEDIUM RANGE MODELS DO HOWEVER TRY AND KNOCK THIS RIDGE BACK
SOUTH BY NEXT WEEKEND AS STRONGER TROUGH TAKES SHAPE TO THE WEST.
THIS MAY RESULT IN A BETTER CHANCE FOR A SFC FRONT TO APPROACH THE
AREA BYE THE END OF NEXT WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 96 72 99 73 / 10 10 10 10
HOBART OK 99 72 101 70 / 10 10 10 10
WICHITA FALLS TX 99 73 101 74 / 10 10 10 10
GAGE OK 100 68 100 69 / 10 10 10 10
PONCA CITY OK 93 71 98 73 / 10 10 10 20
DURANT OK 91 72 98 74 / 60 20 10 10
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
04/02
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
542 PM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SHAPING FOR A NICE AFTERNOON AS FIRST WAVE OFF CIRRUS IS EXITING
EASTERN AREAS. NEXT WAVE TO OUR NW ALREADY SPREADING CIRRUS INTO
NW PA. TEMPERATURES CLOSE TO GUIDANCE.
THE HRRR SHOWS CHANCE OF SHOWERS ALONG NY BORDER BY 2200
UTC...LIGHT AND INCREASES THE INTENSITY AND POTENTIAL BETWEEN 0000
AND 0200 UTC THIS EVENING. MAINLY AFTER THIS FORECAST PERIOD.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 15Z HRRR IS WETTER IN APPEARANCE THAN THE NAM 12KM. BUT SHOWS
BEST CHANCE RAIN AND ISOLATED SHOWERS/THUNDERSTORMS THROUGH 0600
UTC. KEPT HIGHEST POPS NW PA IN THE 0000 TO 0600 UTC TIME PERIOD. THE
HRRR SYNTHETIC RADAR IMPLIES SOME SHOWERS TO CENTRAL PA AND THE
MASS WEAKENS. KEPT POPS LOWER TO SOUTH AND EAST.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY. THE 12Z GEFS IMPLIES PERHAPS
STRONGER FORCING IN THE AFTERNOON MAINLY SOUTH OF MASON/DIXON LINE
SO KEPT SOME CHANCE POPS NEAR AND ALONG IMMEDIATE BORDER WITH
MARYLAND IN THE AFTERNOON. SEE HOW THE 15Z SREF LOOKS LATER TODAY
WITH THIS.
THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND
FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE
CONVECTIVE ALLOWING 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN
CENTRAL/SOUTHERN PA IN MORNING. THEN BEST IMPLIED AREA IS SOUTH OF
THE MARYLAND BORDER SUNDAY AFTERNOON. GRIDS SHOW CHANCE POPS ONLY
IN THE SOUTH.
TEMPERATURES LOOKS CLOSE TO SEASONAL AND NOT MUCH RAIN EXPECTED.
BEST SUNDAY MAY BE IN NW PA WITH THE OVERNIGHT RAINFALL. NOT MUCH
IN ANY MODEL AFTER 1200 UTC SUNDAY. TOTAL QPF IN MOST MODELS IS
ZERO. IN WEST MODELS IMPLY A FEW TENTHS IN MOUNTAINS OF
WESTERN/NORTHWESTERN PA. MOST BEFORE 1200 UTC.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
POST FRONTAL SUNDAY EVENING SHOULD SEE DRY NORTHWESTERLY AIR
ADVECT INTO THE REGION WITH LOWER PWATS INTO MONDAY AFTERNOON.
SREF/GEFS AND DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE
COMING IN FROM THE WEST RELATIVELY FAST. THIS UPPER LEVEL
PERTURBATION SHOULD KEEP MAINLY TO THE SOUTH LATE MONDAY INTO
TUESDAY MORNING. THIS WAVE SHOULD SPREAD MORE CLOUDS AND BRING
RAIN WEST TO EAST ACROSS MAINLY THE SOUTHERN HALF OF PA LATE MONDAY
INTO TUESDAY.
THE BIG EVENT THIS UPCOMING WEEK WILL BE DUE TO THE LARGE UPPER
LEVEL LOW THAT WILL BE MOVING INTO THE GREAT LAKES REGION LATE
TUESDAY. THIS DEEP CLIPPER-LIKE CYCLONE...WITH A EAST TO WEST
BOUNDARY SHOULD BRING HIGH PWATS AND MOIST SOUTH TO SOUTHEASTERLY
FLOW OUT AHEAD OF THE CYCLONE. THIS COULD BE A HEAVY RAIN EVENT
WITH A SYNOPTIC TYPE (S-N FLOW) EVOLVING TO A FRONTAL TYPE WITH
EASTERLY FLOW. EVEN CRUDE GEFS SHOWS ANOMALOUS PWATS TUESDAY
AFTERNOON INTO WEDNESDAY...THOUGH THE STRONGEST ANOMALIES ARE
SOUTH. THIS IMPLIES A 1 TO 2 INCH RAINFALL IS POSSIBLE. THIS
EVENT HAS POTENTIAL TO BE A SIGNIFICANT RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON HAVE INCREASED BUT TEMPERED QPF THROUGH
THIS PERIOD.
THE LARGE UPPER LEVEL LOW LOOKS TO SKIRT ALONG TO THE NORTH OF THE
REGION INTO WEDNESDAY...CUTTING OFF THE MAJOR MOISTURE. BOTH THE
GFS/EC HAVE SIMILAR POSITION AND TIMING WITH THE LOW...WITH
SHOWERY PRECIP POSSIBLE WEDNESDAY AFTERNOON. THIS LOW COULD
RETROGRADE INTO FRIDAY WHICH WILL LEND PRECIPITATION TO BE A
POSSIBILITY THROUGH FRIDAY AFTERNOON. KEPT POPS IN CHANCE RANGE
MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET PATTERN INTO
NEXT WEEKEND.
&&
.AVIATION /22Z SATURDAY THROUGH THURSDAY/...
WIDESPREAD VFR CONDS ACROSS CENTRAL PA AS OF EARLY EVENING.
A WEAKENING COLD FRONT WILL PUSH SE INTO THE AREA TONIGHT...ACCOMPANIED
BY SCT -SHRA. HOWEVER...THE MAIN AVIATION CONCERN WILL BE THE
POTENTIAL OF LOW CIGS AT KBFD LATE TONIGHT...CAUSED BY PLUME OF
PRE-FRONTAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN OF NW PA.
THE THREAT OF LOW CIGS WILL PUSH SOUTHWARD ALONG THE SPINE OF THE
ALLEGHENIES TO KJST IN THE 10Z-14Z TIME FRAME. FURTHER
EAST...A DRYING/DOWNSLOPING FLOW WILL MAKE ANY SIG RESTRICTIONS
MUCH LESS LIKELY.
DYING COLD FRONT WILL SETTLE SOUTH OF THE AREA DURING SUNDAY. ANY
LOW CIGS ARND KJST SHOULD GIVE WAY TO WIDESPREAD VFR CONDS ACROSS
CENTRAL PA...AS DRIER NW FLOW OVERSPREADS THE REGION.
OUTLOOK...
MON...AM FOG POSSIBLE N MTNS...THEN ISOLATED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA.
WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/CERU
AVIATION...GRUMM/FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
401 PM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SHAPING FOR A NICE AFTERNOON AS FIRST WAVE OFF CIRRUS IS EXITING
EASTERN AREAS. NEXT WAVE TO OUR NW ALREADY SPREADING CIRRUS INTO
NW PA. TEMPERATURES CLOSE TO GUIDANCE.
THE HRRR SHOWS CHANCE OF SHOWERS ALONG NY BORDER BY 2200
UTC...LIGHT AND INCREASES THE INTENSITY AND POTENTIAL BETWEEN 0000
AND 0200 UTC THIS EVENING. MAINLY AFTER THIS FORECAST PERIOD.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 15Z HRRR IS WETTER IN APPEARANCE THAN THE NAM 12KM. BUT SHOWS
BEST CHANCE RAIN AND ISOLATED SHOWERS/THUNDERSTORMS THROUGH 0600
UTC. KEPT HIGHEST POPS NW PA IN THE 0000 TO 0600 UTC TIME PERIOD. THE
HRRR SYNTHETIC RADAR IMPLIES SOME SHOWERS TO CENTRAL PA AND THE
MASS WEAKENS. KEPT POPS LOWER TO SOUTH AND EAST.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY. THE 12Z GEFS IMPLIES PERHAPS
STRONGER FORCING IN THE AFTERNOON MAINLY SOUTH OF MASON/DIXON LINE
SO KEPT SOME CHANCE POPS NEAR AND ALONG IMMEDIATE BORDER WITH
MARYLAND IN THE AFTERNOON. SEE HOW THE 15Z SREF LOOKS LATER TODAY
WITH THIS.
THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND
FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE
CONVECTIVE ALLOWING 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN
CENTRAL/SOUTHERN PA IN MORNING. THEN BEST IMPLIED AREA IS SOUTH OF
THE MARYLAND BORDER SUNDAY AFTERNOON. GRIDS SHOW CHANCE POPS ONLY
IN THE SOUTH.
TEMPERATURES LOOKS CLOSE TO SEASONAL AND NOT MUCH RAIN EXPECTED.
BEST SUNDAY MAY BE IN NW PA WITH THE OVERNIGHT RAINFALL. NOT MUCH
IN ANY MODEL AFTER 1200 UTC SUNDAY. TOTAL QPF IN MOST MODELS IS
ZERO. IN WEST MODELS IMPLY A FEW TENTHS IN MOUNTAINS OF
WESTERN/NORTHWESTERN PA. MOST BEFORE 1200 UTC.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
POST FRONTAL SUNDAY EVENING SHOULD SEE DRY NORTHWESTERLY AIR
ADVECT INTO THE REGION WITH LOWER PWATS INTO MONDAY AFTERNOON.
SREF/GEFS AND DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE
COMING IN FROM THE WEST RELATIVELY FAST. THIS UPPER LEVEL
PERTURBATION SHOULD KEEP MAINLY TO THE SOUTH LATE MONDAY INTO
TUESDAY MORNING. THIS WAVE SHOULD SPREAD MORE CLOUDS AND BRING
RAIN WEST TO EAST ACROSS MAINLY THE SOUTHERN HALF OF PA LATE MONDAY
INTO TUESDAY.
THE BIG EVENT THIS UPCOMING WEEK WILL BE DUE TO THE LARGE UPPER
LEVEL LOW THAT WILL BE MOVING INTO THE GREAT LAKES REGION LATE
TUESDAY. THIS DEEP CLIPPER-LIKE CYCLONE...WITH A EAST TO WEST
BOUNDARY SHOULD BRING HIGH PWATS AND MOIST SOUTH TO SOUTHEASTERLY
FLOW OUT AHEAD OF THE CYCLONE. THIS COULD BE A HEAVY RAIN EVENT
WITH A SYNOPTIC TYPE (S-N FLOW) EVOLVING TO A FRONTAL TYPE WITH
EASTERLY FLOW. EVEN CRUDE GEFS SHOWS ANOMALOUS PWATS TUESDAY
AFTERNOON INTO WEDNESDAY...THOUGH THE STRONGEST ANOMALIES ARE
SOUTH. THIS IMPLIES A 1 TO 2 INCH RAINFALL IS POSSIBLE. THIS
EVENT HAS POTENTIAL TO BE A SIGNIFICANT RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON HAVE INCREASED BUT TEMPERED QPF THROUGH
THIS PERIOD.
THE LARGE UPPER LEVEL LOW LOOKS TO SKIRT ALONG TO THE NORTH OF THE
REGION INTO WEDNESDAY...CUTTING OFF THE MAJOR MOISTURE. BOTH THE
GFS/EC HAVE SIMILAR POSITION AND TIMING WITH THE LOW...WITH
SHOWERY PRECIP POSSIBLE WEDNESDAY AFTERNOON. THIS LOW COULD
RETROGRADE INTO FRIDAY WHICH WILL LEND PRECIPITATION TO BE A
POSSIBILITY THROUGH FRIDAY AFTERNOON. KEPT POPS IN CHANCE RANGE
MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET PATTERN INTO
NEXT WEEKEND.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
VFR THE REST OF THIS AFTERNOON AND EVENING. SOME AREAS OF GUSTY
WINDS. FIRST BATCH HIGH CIRRUS PASSING TO OUR EAST. MORE TO OUR
NORTHWEST WILL SPREAD SOUTHEAST THIS AFTERNOON AND INTO EARLY
TONIGHT.
RAIN SHOWERS SOME POTENTIAL FOR MVFR OVERNIGHT IN NW PA. SOME
AREAS OF PATCH FOG AND MVFR ISOLATED IFR OVERNIGHT.
MAINLY VFR AND MVFR SUNDAY WITH SOME LIGHT RAIN SHOWER POTENTIAL
WHICH MOVES TOWARD MARYLAND BORDER DURING THE DAY.
SOME PATCHY FOG OVERNIGHT SUNDAY INTO MONDAY WITH MVFR/IFR AROUND
SUNRISE.
CHANCE MVFR/IFR WITH WEATHER SYSTEM MONDAY NIGHT INTO TUESDAY.
OUTLOOK... SUN...AM LOW CIGS/SHRA POSSIBLE AT KBFD.
MON...AM FOG POSSIBLE N MTNS...THEN ISOLATED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA.
WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/CERU
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
205 PM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
SHAPING FOR A NICE AFTERNOON AS FIRST WAVE OFF CIRRUS IS EXITING
EASTERN AREAS. NEXT WAVE TO OUR NW ALREADY SPREADING CIRRUS INTO
NW PA. TEMPERATURES CLOSE TO GUIDANCE.
THE HRRR SHOWS CHANCE OF SHOWERS ALONG NY BORDER BY 2200
UTC...LIGHT AND INCREASES THE INTENSITY AND POTENTIAL BETWEEN 0000
AND 0200 UTC THIS EVENING. MAINLY AFTER THIS FORECAST PERIOD.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 15Z HRRR IS WETTER IN APPEARANCE THAN THE NAM 12KM. BUT SHOWS
BEST CHANCE RAIN AND ISOLATED SHOWERS/THUNDERSTORMS THROUGH 0600
UTC. KEPT HIGHEST POPS NW PA IN THE 0000 TO 0600 UTC TIME PERIOD. THE
HRRR SYNTHETIC RADAR IMPLIES SOME SHOWERS TO CENTRAL PA AND THE
MASS WEAKENS. KEPT POPS LOWER TO SOUTH AND EAST.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY. THE 12Z GEFS IMPLIES PERHAPS
STRONGER FORCING IN THE AFTERNOON MAINLY SOUTH OF MASON/DIXON LINE
SO KEPT SOME CHANCE POPS NEAR AND ALONG IMMEDIATE BORDER WITH
MARYLAND IN THE AFTERNOON. SEE HOW THE 15Z SREF LOOKS LATER TODAY
WITH THIS.
THE 12Z GEFS/GFS/NAM AND THE 09Z SREF ALL CONTINUE TO SHOW TREND
FOR A PRETTY GOOD AFTERNOON IN CENTRAL AND NORTHERN PA. THE
CONVECTIVE ALLOWING 4KM NAM IMPLIES SHOWERS SCATTERED ABOUT IN
CENTRAL/SOUTHERN PA IN MORNING. THEN BEST IMPLIED AREA IS SOUTH OF
THE MARYLAND BORDER SUNDAY AFTERNOON. GRIDS SHOW CHANCE POPS ONLY
IN THE SOUTH.
TEMPERATURES LOOKS CLOSE TO SEASONAL AND NOT MUCH RAIN EXPECTED.
BEST SUNDAY MAY BE IN NW PA WITH THE OVERNIGHT RAINFALL. NOT MUCH
IN ANY MODEL AFTER 1200 UTC SUNDAY. TOTAL QPF IN MOST MODELS IS
ZERO. IN WEST MODELS IMPLY A FEW TENTHS IN MOUNTAINS OF
WESTERN/NORTHWESTERN PA. MOST BEFORE 1200 UTC.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG EVENT OF WEEK COULD BE RAINFALL TUESDAY....
HIGHEST PROBABILITY OF RAIN THROUGH 8 AM SUNDAY WOULD BE NORTHERN
PA. LOW PROBABILITY OF OVER 1.00 INCH OF RAINFALL IN NORTHERN
AREAS. ENSEMBLES SUGGEST 30 PERCENT OF MEMBERS HAVE MUCH MORE THAN
0.75 INCHES OF QPF.
SUNDAY MODELS FOCUS HIGHER PROBABILITIES IN CENTRAL AND SOUTHERN
PA. MOST AREAS OVER THE PERIOD SUNDAY WILL LIKELY SEE 0.10 TO 0.50
INCHES OF RAIN AS FRONT SAGS SOUTHWARD.
DRY AIR MOVING BEHIND FRONT COULD PROVIDE SOME SUN IN CENTRAL
NORTHERN AREAS IN AFTERNOON SUNDAY.
MONDAY SHOULD START OFF RELATIVELY DRIER...SREF/GEFS AND
DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN
FROM THE WEST RELATIVELY FAST. THIS WAVE SHOULD SPREAD MORE CLOUDS
AND BRING RAIN WEST TO EAST ACROSS PA MONDAY INTO OVERNIGHT
TUESDAY.
EARLY WEEK RAIN SHOULD BE MAIN EVENT...
THE RAIN EVENT OVERNIGHT MONDAY INTO TUESDAY AS FORECAST IS THE
MAIN EVENT OF THE COMING WEEK. DEEP CLIPPER-LIKE CYCLONE...EAST-
WEST BOUNDARY...HIGH PW AND EASTERLY FLOW NORTH OF THE CYCLONE.
THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW)
EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS
SHOWS EASTERLY WIND ANOMALIES. GEFS IMPLIES GOOD 1 TO 2 INCH
RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT
RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON DID NOT GO BIG IN QPF GRIDS AT THIS TIME.
SUSPECT IF THIS SYSTEM DEVELOPS AS FORECAST...OUR HIGHS TUESDAY
COULD GET CRUSHED. BUT AT THIS TIME THIS IS THE EVENT TO MONITOR.
AS THIS SYSTEM SLOWLY GOES BY RAINFALL SHOULD DIMINISH TUESDAY
AND WEDNESDAY. WEDNESDAY AS FORECAST LOOKS RELATIVELY DRY. THEN PW
VALUES RISE AGAIN.
LATER PART OF WEEK LOOKS POTENTIALLY SHOWERY. THE LARGE 500 HPA
RIDGE RETROGRADING TO A POSITION NORTH OF THE GREAT LAKES WILL
LIKELY ALLOW MOISTURE INTO OUR REGION AND KEEP A LARGER SCALE
FRONTAL BOUNDARY NEARBY. THE CMCEFS AND GEFS WILL LIKELY NOT
CAPTURE ANY SHORT WAVES CUTTING UNDER THIS BLOCK. KEPT POPS IN
CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET
PATTERN LAST PART OF THE COMING WORK WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR THE REST OF THIS AFTERNOON AND EVENING. SOME AREAS OF GUSTY
WINDS. FIRST BATCH HIGH CIRRUS PASSING TO OUR EAST. MORE TO OUR
NORTHWEST WILL SPREAD SOUTHEAST THIS AFTERNOON AND INTO EARLY
TONIGHT.
RAIN SHOWERS SOME POTENTIAL FOR MVFR OVERNIGHT IN NW PA. SOME
AREAS OF PATCH FOG AND MVFR ISOLATED IFR OVERNIGHT.
MAINLY VFR AND MVFR SUNDAY WITH SOME LIGHT RAIN SHOWER POTENTIAL
WHICH MOVES TOWARD MARYLAND BORDER DURING THE DAY.
SOME PATCHY FOG OVERNIGHT SUNDAY INTO MONDAY WITH MVFR/IFR AROUND
SUNRISE.
CHANCE MVFR/IFR WITH WEATHER SYSTEM MONDAY NIGHT INTO TUESDAY.
OUTLOOK... SUN...AM LOW CIGS/SHRA POSSIBLE AT KBFD.
MON...AM FOG POSSIBLE N MTNS...THEN ISOLATED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA.
WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1120 AM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
CIRRUS SHIELD CONTINUES TO WORK ITS AWAY ACROSS THE STATE FROM
NORTHWEST TO SOUTHEAST. MOST AREAS WILL SEE PEAKS OF SUN AS HIGH
CLOUDS MOVE BY.
MORE CIRRUS WITH THE WEAK BUT FAST MOVING SHORTWAVE APPROACHES
FROM THE NORTHWEST THIS EVENING INTO SUNDAY. THE NCEP PARALLEL 3
KM HRRR RADAR SIMULATIONS IMPLY THE RAIN WOULD JUST BE ALONG THE
NORTHWEST PA/NY BORDER ABOUT 8 PM AND THEN SHOWS SHOWERS MOVING
INTO NORTHWESTERN PA SHORTLY THERE AFTER. BUT HRRR IMPLIES SHOWERS
POSSIBLE ALONG NY BORDER WARREN/MCKEAN FROM ABOUT 7 PM ON.
PUMPED POPS TO CHANCE UP THERE LATER AFTERNOON IN CASE HRRR IS
SLOW.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 3KM HRRR IMPLIES THIS IS THE BEST CHANCE FOR SHOWERS AND
ISOLATED THUNDERSTORMS IN PA. THE TIMING ALSO FALLS INTO THE HIGH
PROBABILITY PART OF THE 09Z SREF. THE SREF PDF FOR ACCUMULATING
RAINFALL PEAKS IN THE 0000 TO 1200 UTC TIMEFRAME IN NW PA WITH
RAIN LIKELY. HRRR AND SREF ARE COMPLIMENTARY.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY.
THE TREND APPEARS TO BE THIS WAVE IS WEAKER AND NOT AS WET AS
EARLIER RUNS AND SUNDAY IS STARTING TO LOOKS BETTER AS THE DAY
MOVES ON. AT THIS TIME THE SREF IMPLIES RESIDUAL SHOWERS NEAR MD
BORDER AND SOUTH MUCH AFTER 15-18Z SO DROPPED POPS.
SEE HOW 4KM NAM LATER THIS MORNING AND NAM SHOW CONVECTION.
BOTTOM LINE SUNDAY IS LOOKING LIKE BEST CHANCE RAIN EARLY IN
DAY/MORNING WITH SCATTERED SHOWERS SHIFTING RAPIDLY SOUTH. MOST
AREAS SHOULD BE RAIN FREE MOST OF THE DAY. OTHER THAN NW PA RAIN
WOULD BE VERY LIGHT TOO. AND IN NW LOOKING AT 0.10 TO 0.20.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG EVENT OF WEEK COULD BE RAINFALL TUESDAY....
HIGHEST PROBABILITY OF RAIN THROUGH 8 AM SUNDAY WOULD BE NORTHERN
PA. LOW PROBABILITY OF OVER 1.00 INCH OF RAINFALL IN NORTHERN
AREAS. ENSEMBLES SUGGEST 30 PERCENT OF MEMBERS HAVE MUCH MORE THAN
0.75 INCHES OF QPF.
SUNDAY MODELS FOCUS HIGHER PROBABILITIES IN CENTRAL AND SOUTHERN
PA. MOST AREAS OVER THE PERIOD SUNDAY WILL LIKELY SEE 0.10 TO 0.50
INCHES OF RAIN AS FRONT SAGS SOUTHWARD.
DRY AIR MOVING BEHIND FRONT COULD PROVIDE SOME SUN IN CENTRAL
NORTHERN AREAS IN AFTERNOON SUNDAY.
MONDAY SHOULD START OFF RELATIVELY DRIER...SREF/GEFS AND
DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN
FROM THE WEST RELATIVELY FAST. THIS WAVE SHOULD SPREAD MORE CLOUDS
AND BRING RAIN WEST TO EAST ACROSS PA MONDAY INTO OVERNIGHT
TUESDAY.
EARLY WEEK RAIN SHOULD BE MAIN EVENT...
THE RAIN EVENT OVERNIGHT MONDAY INTO TUESDAY AS FORECAST IS THE
MAIN EVENT OF THE COMING WEEK. DEEP CLIPPER-LIKE CYCLONE...EAST-
WEST BOUNDARY...HIGH PW AND EASTERLY FLOW NORTH OF THE CYCLONE.
THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW)
EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS
SHOWS EASTERLY WIND ANOMALIES. GEFS IMPLIES GOOD 1 TO 2 INCH
RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT
RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON DID NOT GO BIG IN QPF GRIDS AT THIS TIME.
SUSPECT IF THIS SYSTEM DEVELOPS AS FORECAST...OUR HIGHS TUESDAY
COULD GET CRUSHED. BUT AT THIS TIME THIS IS THE EVENT TO MONITOR.
AS THIS SYSTEM SLOWLY GOES BY RAINFALL SHOULD DIMINISH TUESDAY
AND WEDNESDAY. WEDNESDAY AS FORECAST LOOKS RELATIVELY DRY. THEN PW
VALUES RISE AGAIN.
LATER PART OF WEEK LOOKS POTENTIALLY SHOWERY. THE LARGE 500 HPA
RIDGE RETROGRADING TO A POSITION NORTH OF THE GREAT LAKES WILL
LIKELY ALLOW MOISTURE INTO OUR REGION AND KEEP A LARGER SCALE
FRONTAL BOUNDARY NEARBY. THE CMCEFS AND GEFS WILL LIKELY NOT
CAPTURE ANY SHORT WAVES CUTTING UNDER THIS BLOCK. KEPT POPS IN
CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET
PATTERN LAST PART OF THE COMING WORK WEEK.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
THE CIRRUS MAY HAVE SLOWED DOWN THE BURNING OFF OF THE FOG AT KIPT
BUT IT IS FINALLY VFR AT KIPT AND WILL BE SO FOR THE REST OF THE
DAY.
CIRRUS WILL STREAM BY TODAY WELL ABOVE 20KFT AND MORE CIRRUS
HEADED OUR WAY OVERNIGHT...ALONG WITH SOME SHOWER ACTIVITY MAINLY
AFTER 00Z SUNDAY. BEST CHANCE RAIN SHOWERS MVFR/IFR WILL BE IN NW
PA OVERNIGHT AND THEN SLIDING SOUTH.
MOST AREAS WILL BE VFR WITH PERIODS MVFR BEFORE AND JUST AFTER
SUNRISE SUNDAY. RAIN SHOWERS WEAKEN SUNDAY AND SHOULD NOT BE
SERIOUS ISSUE. MOST OF THE TIME...AFTER 14-15Z SHOULD BE MAINLY
VFR.
PATCHY FOG OVERNIGHT SUNDAY INTO MONDAY AND POTENTIAL RAIN EVENT
MONDAY NIGHT INTO TUESDAY COULD BRING SOME MVFR/IFR CONDITIONS
INTO THE REGION.
OUTLOOK... SUN...AM LOW CIGS/SHRA POSSIBLE AT
KBFD. MON...AM FOG POSSIBLE N MTNS...THEN SCATTERED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA. WED...SCT PM
TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM
AVIATION...GRUMM
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1051 AM EDT SAT AUG 16 2014
.SYNOPSIS...
THE UNSEASONABLY DEEP TROUGH AND COOL DRY AIR WILL SHIFT TO OUR
EAST. A NORTHWEST FLOW PATTERN WILL DEVELOP. THE MODELS SHOW TWO
SHORTWAVES IN THE NW FLOW TO AFFECT THE REGION. FIRST ONE SUNDAY
AND THE SECOND ONE ABOUT TUESDAY. AT THIS TIME THE SECOND ONE
LOOKS WETTER. THE EVOLVING HIGH LATITUDE BLOCKING 500 HPA HIGH
COULD KEEP MAIN SHORTWAVE TRACK SUPPRESSED TO OUR SOUTH. THE
DEVELOPING 5900M RIDGE OVER THE SOUTHERN USA THIS WEEK SHOULD NOT
AFFECT US OTHER THAN KEEPING THE REGION IN NW FLOW.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
CIRRUS SHIELD CONTINUES TO WORK ITS AWAY ACROSS THE STATE FROM
NORTHWEST TO SOUTHEAST. MOST AREAS WILL SEE PEAKS OF SUN AS HIGH
CLOUDS MOVE BY.
MORE CIRRUS WITH THE WEAK BUT FAST MOVING SHORTWAVE APPROACHES
FROM THE NORTHWEST THIS EVENING INTO SUNDAY. THE NCEP PARALLEL 3
KM HRRR RADAR SIMULATIONS IMPLY THE RAIN WOULD JUST BE ALONG THE
NORTHWEST PA/NY BORDER ABOUT 8 PM AND THEN SHOWS SHOWERS MOVING
INTO NORTHWESTERN PA SHORTLY THERE AFTER. BUT HRRR IMPLIES SHOWERS
POSSIBLE ALONG NY BORDER WARREN/MCKEAN FROM ABOUT 7 PM ON.
PUMPED POPS TO CHANCE UP THERE LATER AFTERNOON IN CASE HRRR IS
SLOW.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE 3KM HRRR IMPLIES THIS IS THE BEST CHANCE FOR SHOWERS AND
ISOLATED THUNDERSTORMS IN PA. THE TIMING ALSO FALLS INTO THE HIGH
PROBABILITY PART OF THE 09Z SREF. THE SREF PDF FOR ACCUMULATING
RAINFALL PEAKS IN THE 0000 TO 1200 UTC TIMEFRAME IN NW PA WITH
RAIN LIKELY. HRRR AND SREF ARE COMPLIMENTARY.
THE SREF SHOWS THE RAINFALL PDF DROPPING AS THE WAVE MOVES INTO
CENTRAL AREAS IN THE 6 TO 18Z RANGE. TRIED TO SHOW IMPROVING
CONDITIONS AND POTENTIALLY A RELATIVELY NICE AFTERNOON OVER MOST
OF CENTRAL AND NORTHERN PA SUNDAY.
THE TREND APPEARS TO BE THIS WAVE IS WEAKER AND NOT AS WET AS
EARLIER RUNS AND SUNDAY IS STARTING TO LOOKS BETTER AS THE DAY
MOVES ON. AT THIS TIME THE SREF IMPLIES RESIDUAL SHOWERS NEAR MD
BORDER AND SOUTH MUCH AFTER 15-18Z SO DROPPED POPS.
SEE HOW 4KM NAM LATER THIS MORNING AND NAM SHOW CONVECTION.
BOTTOM LINE SUNDAY IS LOOKING LIKE BEST CHANCE RAIN EARLY IN
DAY/MORNING WITH SCATTERED SHOWERS SHIFTING RAPIDLY SOUTH. MOST
AREAS SHOULD BE RAIN FREE MOST OF THE DAY. OTHER THAN NW PA RAIN
WOULD BE VERY LIGHT TOO. AND IN NW LOOKING AT 0.10 TO 0.20.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
BIG EVENT OF WEEK COULD BE RAINFALL TUESDAY....
HIGHEST PROBABILITY OF RAIN THROUGH 8 AM SUNDAY WOULD BE NORTHERN
PA. LOW PROBABILITY OF OVER 1.00 INCH OF RAINFALL IN NORTHERN
AREAS. ENSEMBLES SUGGEST 30 PERCENT OF MEMBERS HAVE MUCH MORE THAN
0.75 INCHES OF QPF.
SUNDAY MODELS FOCUS HIGHER PROBABILITIES IN CENTRAL AND SOUTHERN
PA. MOST AREAS OVER THE PERIOD SUNDAY WILL LIKELY SEE 0.10 TO 0.50
INCHES OF RAIN AS FRONT SAGS SOUTHWARD.
DRY AIR MOVING BEHIND FRONT COULD PROVIDE SOME SUN IN CENTRAL
NORTHERN AREAS IN AFTERNOON SUNDAY.
MONDAY SHOULD START OFF RELATIVELY DRIER...SREF/GEFS AND
DETERMINISTIC MODELS SHOW A STRONG WARM SEASON WAVE COMING IN
FROM THE WEST RELATIVELY FAST. THIS WAVE SHOULD SPREAD MORE CLOUDS
AND BRING RAIN WEST TO EAST ACROSS PA MONDAY INTO OVERNIGHT
TUESDAY.
EARLY WEEK RAIN SHOULD BE MAIN EVENT...
THE RAIN EVENT OVERNIGHT MONDAY INTO TUESDAY AS FORECAST IS THE
MAIN EVENT OF THE COMING WEEK. DEEP CLIPPER-LIKE CYCLONE...EAST-
WEST BOUNDARY...HIGH PW AND EASTERLY FLOW NORTH OF THE CYCLONE.
THIS COULD BE A HEAVY RAIN EVENT WITH A SYNOPTIC TYPE (S-N FLOW)
EVOLVING TO A FRONTAL TYPE WITH EASTERLY FLOW. EVEN CRUDE GEFS
SHOWS EASTERLY WIND ANOMALIES. GEFS IMPLIES GOOD 1 TO 2 INCH
RAINFALL IS POSSIBLE. THIS EVENT HAS POTENTIAL TO BE A SIGNIFICANT
RAINFALL EVENT.
LARGER SCALE MODELS SHOW NO SIGNIFICANT CAPE. RAIN/SHOWERS AND
PERHAPS ELEVATED CONVECTION WITH THIS EVENT. DUE TO TIME RANGE AND
PREDICTABILITY HORIZON DID NOT GO BIG IN QPF GRIDS AT THIS TIME.
SUSPECT IF THIS SYSTEM DEVELOPS AS FORECAST...OUR HIGHS TUESDAY
COULD GET CRUSHED. BUT AT THIS TIME THIS IS THE EVENT TO MONITOR.
AS THIS SYSTEM SLOWLY GOES BY RAINFALL SHOULD DIMINISH TUESDAY
AND WEDNESDAY. WEDNESDAY AS FORECAST LOOKS RELATIVELY DRY. THEN PW
VALUES RISE AGAIN.
LATER PART OF WEEK LOOKS POTENTIALLY SHOWERY. THE LARGE 500 HPA
RIDGE RETROGRADING TO A POSITION NORTH OF THE GREAT LAKES WILL
LIKELY ALLOW MOISTURE INTO OUR REGION AND KEEP A LARGER SCALE
FRONTAL BOUNDARY NEARBY. THE CMCEFS AND GEFS WILL LIKELY NOT
CAPTURE ANY SHORT WAVES CUTTING UNDER THIS BLOCK. KEPT POPS IN
CHANCE RANGE MOST OF THE TIME. PRETTY UNSETTLED AND RELATIVELY WET
PATTERN LAST PART OF THE COMING WORK WEEK.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
HIGHLY VARIABLE FOG CONDITIONS CONTINUE ACROSS THE AREA...WITH
SOME LOCATIONS IN LIFR CONDITIONS...AND A GOOD DEAL OF OTHER
LOCATIONS VFR.
LIMITED NATURE OF FOG SHOULD PRECLUDE IT LASTING MUCH PAST 13Z OR
14Z. THEN VFR CONDITIONS WITH JUST SOME HIGH CLOUDS WILL PREVAIL
THE REST OF THE DAY.
NEXT APPROACHING FRONTAL SYSTEM WILL SHOWERS TO WESTERN AND
NORTHWESTERN AREAS AROUND 06Z...SPREADING INTO CENTRAL AREAS
BEFORE 12Z SUNDAY. THIS WILL ACCOMPANIED BY LOWERING VSBYS AND
CIGS. EXPECT WIDESPREAD MVFR CONDITIONS ACROSS WESTERN AND CENTRAL
AREAS BEFORE 12Z SUNDAY.
OUTLOOK...
SUN...AM LOW CIGS/SHRA POSSIBLE AT KBFD.
MON...AM FOG POSSIBLE N MTNS...THEN SCATTERED SHOWERS.
TUE...RAIN/LOW CIGS POSSIBLE...MAINLY SOUTHERN PA.
WED...SCT PM TSRA IMPACTS POSSIBLE W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM
AVIATION...JUNG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1018 PM EDT SUN AUG 17 2014
.SYNOPSIS...
WEAK HIGH PRESSURE ATOP THE REGION THIS WEEKEND WILL GIVE WAY TO A
GRADUAL INFLUX OF MOISTURE ON MONDAY AND TUESDAY WITH IMPROVING
SOUTHWEST FLOW. A SERIES OF LOW PRESSURE SYSTEMS PASSING BY TO THE
NORTH WILL INCREASE THE CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH
MIDWEEK...ESPECIALLY OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 930 PM...AS EXPECTED...PRECIP CONTINUES ITS WEAKENING
TREND...TO THE POINT WHERE ONLY A FEW PATCHES OF LIGHT RAIN AND
ISOLATED SHOWERS REMAINED ACROSS THE FCST AREA. WILL RETAIN A CHANCE
POP OVER THE NC MOUNTAINS...MAINLY S AND W OF I-40...TO ACCOUNT FOR
SHOWERS MOVING IN FROM SE TN. SOME MINOR ADJUSTMENTS WERE MADE TO
THE TEMP TREND BASED ON OBSERVATIONS.
REMAINDER OF PREVIOUS DISCUSSION...
MODELS SEEM TO DIFFER SOMEWHAT AT THIS POINT WITH THE 12Z HIRES WRF
PRODUCTS INDICATING A SECONDARY MCS DEVELOPING AND TRAILING THE
INITIAL LINE BY ABOUT 4-5 HOURS AND ENTERING THE MOUNTAIN ZONES JUST
AFTER MIDNIGHT. THAT SAID...THE HRRR AND LOWER RES 12Z NAM INDICATE
A LULL AS MENTIONED ABOVE WITH INITIAL MCS DECAY...WHICH WAS THE
PREFERRED SOLUTION IN THE FORECAST.
BY DAYBREAK EXPECTING COVERAGE OF SHOWERS AND PERHAPS A THUNDERSTORM
OR TWO TO BE INCREASING ACROSS MOST OF WESTERN NC...AND EVENTUALLY
SPREADING SOUTHEAST INTO THE NC/SC PIEDMONTS BY LATE MORNING INTO
EARLY AFTERNOON. PROFILES LOOK FAIRLY MOIST WHICH WILL INHIBIT
DIURNAL HEATING SOMEWHAT HOWEVER THERE WILL BE NEARLY 1000J/KG
SBCAPE PRESENT BY LATE MORNING. THUS CANNOT RULE OUT A STRONG TO
PERHAPS ISOLATED SEVERE THUNDERSTORM BEFORE THE PRIMARY UPPER
FORCING MECHANISM MOVES OUT LEAVING ONLY THERMODYNAMIC EFFECTS IN
PLAY. ONE ADDITIONAL NOTE...AS MENTIONED ABOVE PROFILES WILL BE
ABUNDANTLY MOIST THEREFORE ANY THUNDERSTORMS COULD PRODUCE
SUBSTANTIAL RAIN RATES LEADING TO MINOR FLASH FLOODING. FORTUNATELY
DUE TO 30-40KTS OF WESTERLY H5 FLOW AND CONTINUED SOUTHWESTERLY FLOW
BENEATH...IT DOES NOT LOOK AS IF ANY CELLS WILL ANCHOR. CONDITIONS
WILL SLOWLY IMPROVE TOWARDS THE LATE AFTERNOON ACROSS THE SOUTHWEST
WITH THE NORTHEASTERN ZONES TO FOLLOW AS THE WAVE DEPARTS. AS FOR
THE FORECAST...CHANCE POPS ARE FEATURED ACROSS THE MOUNTAINS WITH
ONLY SLIGHT CHANCE POPS ACROSS THE FOOTHILLS FOR THIS AFTERNOON AND
EVENING. POPS ON MONDAY WILL FEATURE LIKELY LEVELS ACROSS MUCH OF
WESTERN NC WITH SOLID CHANCE LEVEL POPS ELSEHWERE. TEMPERATURES WILL
BE COOLER ON MONDAY AS PARTLY/MOSTLY CLOUDY SKIES PREVAIL YIELDING
BELOW NORMAL TEMPERATURES.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 255 PM SUNDAY...NEARLY ZONAL FLOW REMAINS ACROSS THE AREA THRU
THE PERIOD AS AN UPPER LOW MOVES TO THE GREAT LAKES AND A RIDGE
BUILDS OVER THE LOWER MS RIVER VALLEY AND GULF COAST. A SHORT WAVE
TO THE SOUTH MOVES INTO THE AREA TUE...ANOTHER SHORT WAVE MOVES
ACROSS THE NORTH TUE NITE WITH ANOTHER WEAK WAVE ACROSS THE AREA
WED. AT THE SFC...A QUASI STATIONARY FRONT REMAINS TO OUR NORTH WITH
A LEE TROF NEAR THE FALL LINE. THERE WILL BE WAVES OF MOISTURE
MOVING INTO THE AREA WITH THE WAVES...ALMOST MCS LIKE. HOWEVER...
THERE IS QUITE A BIT OF SPREAD IN THE GUIDANCE SOLUTIONS REGARDING
CONVECTIVE COVERAGE. IN ADDITION...THERE IS LITTLE IN THE WAY OF LOW
LEVEL SLY FLOW WITH LOW LEVEL RIDGING KEEPING THE WINDS MORE WLY.
ALSO...LFC LEVELS REMAIN HIGH ACROSS THE SOUTH...BUT DO LOWER ACROSS
THE MTNS AND NRN TIER WHERE LOW LEVEL MOISTURE INCREASES THE MOST.
THERE IS QUITE A BIT OF ELEVATED INSTABILITY HOWEVER...SO ANY
FORCING THAT CAN LIFT THE PARCELS TO THAT LEVEL WILL ALLOW CONVECTION
TO BE REALIZED. THEREFORE...HAVE CONTINUED THE PREV TREND OF HIGHEST
POP MTNS AND NRN TIER THRU THE PERIOD...WITH A DIURNAL TREND. THAT
SAID...KEEP POP ACROSS THE MTNS OVERNIGHT TO ACCOUNT FOR ANY MCS
ACTIVITY THAT DOES MAKE IT THIS FAR EAST. LOWS WILL REMAIN NEARLY
STEADY A LITTLE ABOVE NORMAL. HIGHS WILL BE NEAR TO SLIGHTLY ABOVE
NORMAL TUE...THEN WARM A COUPLE OF DEGREES WED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 2 PM EDT SUNDAY...THE MEDIUM RANGE PICKS UP AT 00Z ON THURSDAY
WITH RELATIVELY FLAT UPPER RIDGING OVER THE SE CONUS AND A HEALTHY
LOOKING UPPER SHORTWAVE CROSSING THE SOUTHERN GREAT LAKES TO OUR
NORTH. OVER THE NEXT COUPLE OF DAYS...THE LONG RANGE MODELS HAVE THE
UPPER RIDGE RETROGRADING BACK TOWARDS THE WEST WHILE THE ABOVE
SHORTWAVE BECOME ABSORBED BACK INTO MEAN UPPER FLOW AND A BROADER
UPPER TROF DEVELOPS JUST OFF THE NEW ENGLAND COAST. FOR THE
REMAINDER OF THE PERIOD...THE RIDGE AXIS REMAINS IN PLACE TO OUR
WEST WHILE THE UPPER TROF BECOMES NEARLY STATIONARY AND MORPHS INTO
A CLOSED H5 LOW BY DAY 7.
AT THE SFC...OUR AREA IS EXPECTED TO REMAIN UNDER A WARM AND MOIST
AIR MASS THRU THE PERIOD WITH WEAK HIGH PRESSURE IN PLACE AND A
SERIES OF WEAK MESO LOWS THAT TRY TO SPIN UP TO OUR NORTH AND EAST.
AS WOULD BE EXPECTED...MODEL PLACEMENT AND TIMING OF THESE LOWS IS
SPORADIC BETWEEN RUNS WITH THE DEEPER LYR MOISTURE ASSOCIATED WITH
THE NEAR SFC FEATURES GENERALLY CONFINED TO OUR NORTH AND EAST. THE
DEEPER MOISTURE APPEARS TO SPREAD MORE TO THE WEST OVER THE WEEKEND
SO SAT AND SUN SHOULD BE OUR BEST SHOT AT WIDESPREAD DIURNAL
CONVECTION. OTHERWISE...POPS FOLLOW A TYPICAL LATE SUMMERTIME
DIURNAL SLIGHT CHANCE TO CHANCE. TEMPS WILL START OUT ABOUT A
CATEGORY ABOVE NORMAL ON THURS AND STEADILY COOL THRU DAY 7 WITH
VALUES ENDING RIGHT AROUND CLIMO.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT AND MONDAY
MORNING. CONVECTION SEEN ON THE KGSP RADAR STANDS ONLY A SMALL
CHANCE OF SURVIVING LONG ENOUGH AS THE BOUNDARY LAYER COOLS AND
STABILIZES AFTER SUNSET. INSTEAD...EXPECT HIGH BASED STRATOCU AND
ALTOCU TO FORM A VFR CEILING. A LIGHT SW TO S WIND WILL PREVAIL. ON
MONDAY...THE MODELS ARE FAIRLY CONSISTENT WITH MOISTURE CONVERGENCE
OVER THE PIEDMONT BEGINNING AROUND 16Z THROUGH THE END OF THE
PERIOD...AND THE MODELS ALSO DEVELOP SOME PRECIP DURING THAT TIME
FRAME. AN APPROACHING UPPER WAVE WILL HELP TO INCREASE MOISTURE AND
BRING A STRONGER SW WIND. THIS SHOULD PROVIDE FOR A VFR CEILING IN
THE 040-060 RANGE IN THE MORNING AND EARLY AFTERNOON. THE PRECIP
CHANCE WILL BE HANDLED WITH A PROB30 FOR THE TIME BEING IN THE 16Z
TO 22Z TIME FRAME...BUT THE CHANCE WILL PERSIST INTO MONDAY EVENING.
ELSEWHERE...THE MAIN CONCERN IS CONVECTIVE PRECIP SEEN ON THE KGSP
RADAR...BUT A DIMINISHING TREND IS EXPECTED AS THE SHOWERS WORK
FARTHER E OVER THE CAROLINAS. HAVE LIMITED THE TAFS TO ONLY A VCSH
AND WILL AMEND IF MORE COHERENT RADAR ECHOES APPROACH A TAF SITE.
FOR THE MOST PART...VFR CONDITIONS WILL PREVAIL AT THE MAJORITY OF
THE FORECAST SITES UNTIL THE EARLY MORNING HOURS. KAVL WILL HAVE A
HIGHER CHANCE OF SEEING FOG DEVELOPING IN THE VALLEY AROUND DAYBREAK
SO AN MVFR VSBY WAS INCLUDED. THE OTHER SITES COULD SEE AN MVFR
CLOUD DECK IN THE EARLY MORNING HOURS AROUND DAYBREAK ACCORDING TO
THE LAMP GUIDANCE...WHICH WAS GENERALLY ACCEPTED. OTHERWISE...
PREVAILING VFR FROM MID MORNING ONWARD. ALL SITES WILL HAVE THE
POSSIBILITY OF THUNDERSTORMS ON MONDAY AFTERNOON...AND THE FCST WAS
HANDLED SIMILAR TO KCLT. WINDS THROUGH THE PERIOD WILL REMAIN
PREDOMINATELY OUT OF THE SOUTHWEST ASIDE FOR AT KAVL WHERE WINDS ARE
CHANNELED FROM THE NORTHWEST.
OUTLOOK...CHANCES FOR PRECIP AND CIG/VSBY RESTRICIONS WILL REMAIN
ELEVATED THROUGH MONDAY NIGHT AS AN UPPER DISTURBANCE SPREADS
CONVECTION ACROSS THE REGION. UPPER LEVEL RIDGING WILL SET IN BY
MIDWEEK WITH ENOUGH MOISTURE IN THE PROFILE TO SUPPORT DIURNAL
CONVECTION THROUGH WEEKS END LEADING TO AFTERNOON TSRA RESTRICTIONS
AND POSSIBLE EARLY MORNING FOG.
CONFIDENCE TABLE...
02-08Z 08-14Z 14-20Z 20-02Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 92% HIGH 92% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 95% HIGH 95% HIGH 100%
KHKY HIGH 100% MED 70% HIGH 100% HIGH 100%
KGMU HIGH 92% HIGH 85% HIGH 100% HIGH 100%
KAND HIGH 92% MED 62% HIGH 86% 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...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...CDG/PM
SHORT TERM...RWH
LONG TERM...JPT
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
756 PM EDT SUN AUG 17 2014
.SYNOPSIS...
WEAK HIGH PRESSURE ATOP THE REGION THIS WEEKEND WILL GIVE WAY TO A
GRADUAL INFLUX OF MOISTURE ON MONDAY AND TUESDAY WITH IMPROVING
SOUTHWEST FLOW. A SERIES OF LOW PRESSURE SYSTEMS PASSING BY TO THE
NORTH WILL INCREASE THE CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH
MIDWEEK...ESPECIALLY OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 730 PM...AS EXPECTED...PRECIP MOVING IN FROM SE TN AND N GA
CONTINUES TO WEAKEN AS IT FIGHTS ITS WAY INTO A LESS FAVORABLE
ENVIRONMENT. HAVE EXTENDED A CHANCE POP ACROSS THE LAKELANDS AND
OVER PARTS OF THE NRN FOOTHILLS OF NC BASED ON RADAR TRENDS. THINK
THE LIKELY POP OVER THE SRN MOUNTAINS LOOKS GOOD WITH A LOWERING
TREND INTO THE LATE EVE. TEMPS ARE IN GOOD SHAPE.
REMAINDER OF PREVIOUS DISCUSSION...
MODELS INDICATE THIS INITIAL MCS WILL LIKELY DECAY SOMEWHAT WITH
HEATING LOSS AS IT ENTERS THE HIGH TERRAIN OF WESTERN NC AND
NORTHEAST GA BY EARLY EVENING. HOWEVER...PROFILES ACROSS THIS
REGION WILL REMAIN SUPPORTIVE OF MILDLY STRONG UPDRAFTS THEREFORE A
FEW THUNDERSTORMS CANNOT BE RULED OUT ACROSS THE MOUNTAINS THROUGH
MID/LATE EVENING. MODELS SEEM TO DIFFER SOMEWHAT AT THIS POINT WITH
THE 12Z HIRES WRF PRODUCTS INDICATING A SECONDARY MCS DEVELOPING AND
TRAILING THE INITIAL LINE BY ABOUT 4-5 HOURS AND ENTERING THE
MOUNTAIN ZONES JUST AFTER MIDNIGHT. THAT SAID...THE HRRR AND LOWER
RES 12Z NAM INDICATE A LULL AS MENTIONED ABOVE WITH INITIAL MCS
DECAY...WHICH WAS THE PREFERRED SOLUTION IN THE FORECAST.
BY DAYBREAK EXPECTING COVERAGE OF SHOWERS AND PERHAPS A THUNDERSTORM
OR TWO TO BE INCREASING ACROSS MOST OF WESTERN NC...AND EVENTUALLY
SPREADING SOUTHEAST INTO THE NC/SC PIEDMONTS BY LATE MORNING INTO
EARLY AFTERNOON. PROFILES LOOK FAIRLY MOIST WHICH WILL INHIBIT
DIURNAL HEATING SOMEWHAT HOWEVER THERE WILL BE NEARLY 1000J/KG
SBCAPE PRESENT BY LATE MORNING. THUS CANNOT RULE OUT A STRONG TO
PERHAPS ISOLATED SEVERE THUNDERSTORM BEFORE THE PRIMARY UPPER
FORCING MECHANISM MOVES OUT LEAVING ONLY THERMODYNAMIC EFFECTS IN
PLAY. ONE ADDITIONAL NOTE...AS MENTIONED ABOVE PROFILES WILL BE
ABUNDANTLY MOIST THEREFORE ANY THUNDERSTORMS COULD PRODUCE
SUBSTANTIAL RAIN RATES LEADING TO MINOR FLASH FLOODING. FORTUNATELY
DUE TO 30-40KTS OF WESTERLY H5 FLOW AND CONTINUED SOUTHWESTERLY FLOW
BENEATH...IT DOES NOT LOOK AS IF ANY CELLS WILL ANCHOR. CONDITIONS
WILL SLOWLY IMPROVE TOWARDS THE LATE AFTERNOON ACROSS THE SOUTHWEST
WITH THE NORTHEASTERN ZONES TO FOLLOW AS THE WAVE DEPARTS. AS FOR
THE FORECAST...CHANCE POPS ARE FEATURED ACROSS THE MOUNTAINS WITH
ONLY SLIGHT CHANCE POPS ACROSS THE FOOTHILLS FOR THIS AFTERNOON AND
EVENING. POPS ON MONDAY WILL FEATURE LIKELY LEVELS ACROSS MUCH OF
WESTERN NC WITH SOLID CHANCE LEVEL POPS ELSEHWERE. TEMPERATURES WILL
BE COOLER ON MONDAY AS PARTLY/MOSTLY CLOUDY SKIES PREVAIL YIELDING
BELOW NORMAL TEMPERATURES.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 255 PM SUNDAY...NEARLY ZONAL FLOW REMAINS ACROSS THE AREA THRU
THE PERIOD AS AN UPPER LOW MOVES TO THE GREAT LAKES AND A RIDGE
BUILDS OVER THE LOWER MS RIVER VALLEY AND GULF COAST. A SHORT WAVE
TO THE SOUTH MOVES INTO THE AREA TUE...ANOTHER SHORT WAVE MOVES
ACROSS THE NORTH TUE NITE WITH ANOTHER WEAK WAVE ACROSS THE AREA
WED. AT THE SFC...A QUASI STATIONARY FRONT REMAINS TO OUR NORTH WITH
A LEE TROF NEAR THE FALL LINE. THERE WILL BE WAVES OF MOISTURE
MOVING INTO THE AREA WITH THE WAVES...ALMOST MCS LIKE. HOWEVER...
THERE IS QUITE A BIT OF SPREAD IN THE GUIDANCE SOLUTIONS REGARDING
CONVECTIVE COVERAGE. IN ADDITION...THERE IS LITTLE IN THE WAY OF LOW
LEVEL SLY FLOW WITH LOW LEVEL RIDGING KEEPING THE WINDS MORE WLY.
ALSO...LFC LEVELS REMAIN HIGH ACROSS THE SOUTH...BUT DO LOWER ACROSS
THE MTNS AND NRN TIER WHERE LOW LEVEL MOISTURE INCREASES THE MOST.
THERE IS QUITE A BIT OF ELEVATED INSTABILITY HOWEVER...SO ANY
FORCING THAT CAN LIFT THE PARCELS TO THAT LEVEL WILL ALLOW CONVECTION
TO BE REALIZED. THEREFORE...HAVE CONTINUED THE PREV TREND OF HIGHEST
POP MTNS AND NRN TIER THRU THE PERIOD...WITH A DIURNAL TREND. THAT
SAID...KEEP POP ACROSS THE MTNS OVERNIGHT TO ACCOUNT FOR ANY MCS
ACTIVITY THAT DOES MAKE IT THIS FAR EAST. LOWS WILL REMAIN NEARLY
STEADY A LITTLE ABOVE NORMAL. HIGHS WILL BE NEAR TO SLIGHTLY ABOVE
NORMAL TUE...THEN WARM A COUPLE OF DEGREES WED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 2 PM EDT SUNDAY...THE MEDIUM RANGE PICKS UP AT 00Z ON THURSDAY
WITH RELATIVELY FLAT UPPER RIDGING OVER THE SE CONUS AND A HEALTHY
LOOKING UPPER SHORTWAVE CROSSING THE SOUTHERN GREAT LAKES TO OUR
NORTH. OVER THE NEXT COUPLE OF DAYS...THE LONG RANGE MODELS HAVE THE
UPPER RIDGE RETROGRADING BACK TOWARDS THE WEST WHILE THE ABOVE
SHORTWAVE BECOME ABSORBED BACK INTO MEAN UPPER FLOW AND A BROADER
UPPER TROF DEVELOPS JUST OFF THE NEW ENGLAND COAST. FOR THE
REMAINDER OF THE PERIOD...THE RIDGE AXIS REMAINS IN PLACE TO OUR
WEST WHILE THE UPPER TROF BECOMES NEARLY STATIONARY AND MORPHS INTO
A CLOSED H5 LOW BY DAY 7.
AT THE SFC...OUR AREA IS EXPECTED TO REMAIN UNDER A WARM AND MOIST
AIR MASS THRU THE PERIOD WITH WEAK HIGH PRESSURE IN PLACE AND A
SERIES OF WEAK MESO LOWS THAT TRY TO SPIN UP TO OUR NORTH AND EAST.
AS WOULD BE EXPECTED...MODEL PLACEMENT AND TIMING OF THESE LOWS IS
SPORADIC BETWEEN RUNS WITH THE DEEPER LYR MOISTURE ASSOCIATED WITH
THE NEAR SFC FEATURES GENERALLY CONFINED TO OUR NORTH AND EAST. THE
DEEPER MOISTURE APPEARS TO SPREAD MORE TO THE WEST OVER THE WEEKEND
SO SAT AND SUN SHOULD BE OUR BEST SHOT AT WIDESPREAD DIURNAL
CONVECTION. OTHERWISE...POPS FOLLOW A TYPICAL LATE SUMMERTIME
DIURNAL SLIGHT CHANCE TO CHANCE. TEMPS WILL START OUT ABOUT A
CATEGORY ABOVE NORMAL ON THURS AND STEADILY COOL THRU DAY 7 WITH
VALUES ENDING RIGHT AROUND CLIMO.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS WILL PREVAIL THROUGH TONIGHT AND MONDAY
MORNING. CONVECTION SEEN ON THE KGSP RADAR STANDS ONLY A SMALL
CHANCE OF SURVIVING LONG ENOUGH AS THE BOUNDARY LAYER COOLS AND
STABILIZES AFTER SUNSET. INSTEAD...EXPECT HIGH BASED STRATOCU AND
ALTOCU TO FORM A VFR CEILING. A LIGHT SW TO S WIND WILL PREVAIL. ON
MONDAY...THE MODELS ARE FAIRLY CONSISTENT WITH MOISTURE CONVERGENCE
OVER THE PIEDMONT BEGINNING AROUND 16Z THROUGH THE END OF THE
PERIOD...AND THE MODELS ALSO DEVELOP SOME PRECIP DURING THAT TIME
FRAME. AN APPROACHING UPPER WAVE WILL HELP TO INCREASE MOISTURE AND
BRING A STRONGER SW WIND. THIS SHOULD PROVIDE FOR A VFR CEILING IN
THE 040-060 RANGE IN THE MORNING AND EARLY AFTERNOON. THE PRECIP
CHANCE WILL BE HANDLED WITH A PROB30 FOR THE TIME BEING IN THE 16Z
TO 22Z TIME FRAME...BUT THE CHANCE WILL PERSIST INTO MONDAY EVENING.
ELSEWHERE...THE MAIN CONCERN IS CONVECTIVE PRECIP SEEN ON THE KGSP
RADAR...BUT A DIMINISHING TREND IS EXPECTED AS THE SHOWERS WORK
FARTHER E OVER THE CAROLINAS. HAVE LIMITED THE TAFS TO ONLY A VCSH
AND WILL AMEND IF MORE COHERENT RADAR ECHOES APPROACH A TAF SITE.
FOR THE MOST PART...VFR CONDITIONS WILL PREVAIL AT THE MAJORITY OF
THE FORECAST SITES UNTIL THE EARLY MORNING HOURS. KAVL WILL HAVE A
HIGHER CHANCE OF SEEING FOG DEVELOPING IN THE VALLEY AROUND DAYBREAK
SO AN MVFR VSBY WAS INCLUDED. THE OTHER SITES COULD SEE AN MVFR
CLOUD DECK IN THE EARLY MORNING HOURS AROUND DAYBREAK ACCORDING TO
THE LAMP GUIDANCE...WHICH WAS GENERALLY ACCEPTED. OTHERWISE...
PREVAILING VFR FROM MID MORNING ONWARD. ALL SITES WILL HAVE THE
POSSIBILITY OF THUNDERSTORMS ON MONDAY AFTERNOON...AND THE FCST WAS
HANDLED SIMILAR TO KCLT. WINDS THROUGH THE PERIOD WILL REMAIN
PREDOMINATELY OUT OF THE SOUTHWEST ASIDE FOR AT KAVL WHERE WINDS ARE
CHANNELED FROM THE NORTHWEST.
OUTLOOK...CHANCES FOR PRECIP AND CIG/VSBY RESTRICIONS WILL REMAIN
ELEVATED THROUGH MONDAY NIGHT AS AN UPPER DISTURBANCE SPREADS
CONVECTION ACROSS THE REGION. UPPER LEVEL RIDGING WILL SET IN BY
MIDWEEK WITH ENOUGH MOISTURE IN THE PROFILE TO SUPPORT DIURNAL
CONVECTION THROUGH WEEKS END LEADING TO AFTERNOON TSRA RESTRICTIONS
AND POSSIBLE EARLY MORNING FOG.
CONFIDENCE TABLE...
00-06Z 06-12Z 12-18Z 18-24Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 92% HIGH 92% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 91% HIGH 100%
KHKY HIGH 100% HIGH 82% HIGH 91% HIGH 100%
KGMU HIGH 92% HIGH 86% HIGH 100% HIGH 100%
KAND HIGH 100% MED 74% MED 73% 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...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...CDG/PM
SHORT TERM...RWH
LONG TERM...JPT
AVIATION...PM
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
539 AM CDT SAT AUG 16 2014
.DISCUSSION...
SEE AVIATION FOR 12Z TAF ISSUANCE.
&&
.AVIATION...
HIGH PRESSURE OVER THE GULF OF MEXICO WILL ALLOW SOUTHERLY WINDS
TO CONTINUE TODAY. THE SEA BREEZE IS AGAIN EXPECTED TO MOVE INLAND
TODAY PRODUCING ISOLATED SHOWERS AND THUNDERSTORMS. THE TEXAS TECH
WRF SEEMS A BIT OVER DONE FOR TODAY BUT THE HIGH RES RAP AND HRRR
MODEL SEEM MORE ON PAR KEEPING THE COVERAGE ISOLATED. SOME STORMS
COULD MAKE IT FARTHER INLAND TODAY AS PWATS HAVE CONTINUED THEIR
SLOW CLIMB. MOSTLY VFR CONDITIONS EXPECTED THROUGH THE ISSUANCE.
23
&&
.PREV DISCUSSION... /ISSUED 456 AM CDT SAT AUG 16 2014/
DISCUSSION...
SCATTERED SHOWERS DEVELOPING ACROSS THE COASTAL WATERS THIS
MORNING SO FAR MAINLY SOUTHEAST OF LINE FROM HIGH ISLAND TO 40 NM
SOUTH OF FREEPORT. ANOTHER HOT AUGUST DAY ON TAP WITH RIDGING
INFLUENCE STILL PRESENT AND EXPECT TEMPERATURES TO REACH INTO THE
UPPER 90S AND HEAT INDEX READINGS OF 101 TO 105 BEING COMMON THIS
AFTERNOON AND AGAIN SUNDAY...PERHAPS A DEGREE OR TWO HOTTER
SUNDAY. RAIN CHANCES LOOK SLIM TODAY AGAIN AND WILL PROBABLY ONLY
SEE A FEW SHOWERS DOT THE SOUTHERN AREAS.
SUNDAY GETS MORE INTERESTING WITH THE UPPER SHEAR AXIS IN THE GULF
MOVING WEST AND A S/W MOVING UP INTO THE AREA FROM THE SOUTH AND
ANOTHER FROM THE WEST. PRECIPITABLE WATER VALUES CLIMB TO 1.8-2.1"
AND INSTABILITY INCREASES. EXPECT SCATTERED SHOWERS IN THE MORNING
TO TRANSITION TO MORE THUNDERSTORMS AS THE GULF STORMS SPREAD
INLAND IN THE MORNING. HAVE RAISED POPS A LITTLE AND EXPANDED
INLAND. GUSTY WINDS AND HEAVY DOWNPOURS WILL ACCOMPANY THE STORMS
BUT NOT EXPECTING SEVERE WINDS BUT MAY HAVE SOME ISSUES WITH HEAVY
RAIN. MONDAY THE RIDGING FROM LA/GULF EXPANDS WEST AND DRIER AIR
EXPANDS OVERHEAD WITH LESS COVERAGE OF STORMS. RAIN CHANCES
GRADUALLY DECREASING MONDAY THROUGH FRIDAY WITH THE PATTERN
RETURNING TO MORE ISOLATED SHOWERS WITH AFTERNOON TEMPERATURES
REMAINING IN THE MID TO UPPER 90S. BY FRIDAY THE GUIDANCE IS
SHARPLY DIVERGING AND FOR NOW WILL FAVOR THE GFS AND ENSEMBLE
SOLUTIONS WITH UPPER RIDGING TAKING HOLD OVER THE AREA.
45
MARINE...
WINDS HAVE STARTED TO COME UP OVER THE WATERS THIS
MORNING THANKS TO THE SLIGHTLY TIGHTER PRESSURE GRADIENT. THE
WESTERN AREAS OF THE WATERS WILL APPROACH CAUTION CRITERIA SATURDAY
NIGHT INTO EARLY SUNDAY MORNING THANKS TO A WEAK SURFACE LOW IN WEST
TEXAS. THERE WILL ALSO BE A CHANCE OF ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS LATE NIGHT INTO EARLY MORNING EACH DAY. 23
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 98 77 97 77 96 / 10 10 20 10 10
HOUSTON (IAH) 96 77 94 77 95 / 20 10 30 10 20
GALVESTON (GLS) 92 83 90 82 90 / 20 20 40 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...45
AVIATION/MARINE...23
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CDT SAT AUG 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT SAT AUG 16 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE SOUTHWESTERN U.S....AN UPPER LOW IN NORTHERN
IDAHO...SHORTWAVES OVER THE DAKOTAS AND THE KANSAS CITY AREA...AND A
DEEP UPPER TROUGH OVER EASTERN CANADA INTO THE NORTHEAST U.S..
WITHIN THIS TROUGH...A FAIRLY POTENT SHORTWAVE WAS APPROACHING LAKE
SUPERIOR. THE FORECAST AREA LIES IN THE NORTHWEST FLOW ON THE
WESTERN EDGE OF THE TROUGH...BUT STILL NEAR THE INFLECTION POINT
FAVORING SUBSIDENCE AND HIGH PRESSURE AT THE SURFACE. THUS...ONLY
SOME SCATTERED CIRRUS CLOUDS HAVE BEEN TRACKING ACROSS THE FORECAST
AREA. 15.00Z MODELS DEFINITELY OVER-FORECAST THE PRECIPITABLE
WATER...INSTEAD OF BEING 1.5-1.75 INCHES IS ONLY 1-1.25 INCHES PER
GOES DERIVED IMAGERY. SURFACE DEWPOINTS ARE HIGHER...THOUGH...WHICH
WITH RADIATIONAL COOLING HAS LED TO SOME BR AND LOW STRATUS
DEVELOPMENT. THE NEAREST AREAS WHERE PRECIPITATION IS OCCURRING ARE
SOUTH OF I-80 IN IOWA ASSOCIATED WITH THE KANSAS CITY SHORTWAVE...
OVER THE CENTRAL DAKOTAS WITH THE SHORTWAVE THERE...AND THE MN
ARROWHEAD INTO UPPER MICHIGAN AHEAD OF THE APPROACHING SHORTWAVE.
THIS LAST PRECIPITATION AREA IS ALSO SUPPORTED BY A SURFACE COLD
FRONT TRACKING WITH IT.
500MB HEIGHTS ARE PROGGED TO RISE OVER THE NEXT 24 HOURS IN RESPONSE
TO THE UPPER LOW OVER NORTHERN ONTARIO PUSHING EAST INTO SOUTH
CENTRAL SASKATCHEWAN. TYPICALLY WHEN SEEING HEIGHT RISES ONE WOULD
EXPECT A WARM ADVECTION PATTERN. HOWEVER...IN THIS CASE...THE
SHORTWAVE APPROACHING LAKE SUPERIOR WILL DROP INTO THE EASTERN GREAT
LAKES THIS EVENING...SENDING ITS ASSOCIATED COLD FRONT THROUGH THE
FORECAST AREA.
MUCH OF THIS MORNING CONTINUES TO LOOK DRY AS ANY SHOWER ACTIVITY
ASSOCIATED WITH THE KANSAS CITY SHORTWAVE STAYS JUST TO THE
SOUTH...AS DEPICTED IN THE LATEST RAP/HRRR DATA. ANY FOG/STRATUS
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNRISE. HEADING INTO THE
AFTERNOON...DETERMINISTIC AND HIGH RESOLUTION MODELS REMAIN IN GOOD
AGREEMENT THAT THIS COLD FRONT WILL HELP INITIATE CONVECTION NORTH
OF I-94. THIS IS A RESULT TOO OF TEMPERATURES CLIMBING INTO THE 80S
FROM 850MB TEMPS AROUND 16C...AS WELL AS DEWPOINTS CLIMBING INTO THE
MID TO UPPER 60S...COMBINING TO PRODUCE MLCAPES OF 1000-2000 J/KG.
THIS CAPE IS OVERALL SKINNY AND 0-6 KM/0-3KM SHEAR ARE 20 KT OR LESS
WHICH WILL LIMIT SEVERE WEATHER POTENTIAL. HOWEVER...EQUILIBRIUM
LEVELS ARE NEAR 40000 FT AND WARM CLOUD DEPTHS APPROACH 4000
METERS...SO THE STORMS ARE LIKELY TO PRODUCE HEAVY RAIN. THE AMOUNT
OF CONVECTION SEEMS SCATTERED AT BEST SINCE THE BETTER FRONTAL
CONVERGENCE AND DYNAMIC FORCING ARE FARTHER EAST...MORE TOWARDS
LOWER MICHIGAN CLOSER TO THE SHORTWAVE TRACK.
CONVECTION NORTH OF I-94 IN THE AFTERNOON THEN LOOKS TO DROP SOUTH
IN THE EVENING WITH THE COLD FRONT. HOWEVER...COOLING TEMPERATURES
FROM LOSS OF DAYTIME HEATING AND THE FACT LITTLE CONVERGENCE EXISTS
ON THE FRONT WILL LIKELY RESULT IN A DIMINISHING TREND TO THE
CONVECTION. THERE MAY NOT BE MUCH LEFT AFTER 06Z AS THE 16.00Z GFS
SUGGESTS. IN THE WAKE OF THE COLD FRONT...IT APPEARS A LOW STRATUS
DECK MAY END UP DEVELOPING AND ADVECTING SOUTHWESTWARD. BASED ON
FORECAST SOUNDINGS...LOCATIONS SOUTHWEST OF I-94 APPEAR TO HAVE THE
GREATEST CHANCE OF SEEING THIS STRATUS DECK. COOLING 925MB TEMPS ON
THE EASTERLY FLOW SHOULD RESULT IN A COOLER NIGHT...ESPECIALLY IN
CENTRAL WI.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 253 AM CDT SAT AUG 16 2014
MAIN ISSUE ON SUNDAY RELATES TO THE SHORTWAVE OVER THE DAKOTAS
CURRENTLY. THE 16.00Z GFS/NAM TRACK THIS SHORTWAVE ACROSS MN DURING
THE DAY...WHICH HELPS PRODUCE SOME SHOWERS AND EMBEDDED STORMS
MOSTLY JUST WEST OF THE FORECAST AREA. PART OF THE REASON THIS
PRECIPITATION DOESNT DEVELOP FARTHER EAST IS A DRY EASTERLY FLOW
PROVIDED BY HIGH PRESSURE BUILDING OVER UPPER MI IN THE WAKE OF
TONIGHTS COLD FRONT. ITS POSSIBLE SOME OF THE SHOWER ACTIVITY
CREEPS INTO SOUTHEAST MN...BUT CONFIDENCE IS NOT HIGH ENOUGH TO PUT
ANY CHANCES IN YET. OTHERWISE...SUNDAY LOOKS COOLER THAN TODAY DUE
TO THE EASTERLY FLOW...MORNING STRATUS AND 925MB TEMPS ABOUT 4C
COOLER.
SUNDAY NIGHT NOW POSES SOME FORECAST CHALLENGE. 16.00Z ECMWF IS
SLOWER THAN THE GFS/NAM TRACKING THE SHORTWAVE EASTWARD OUT OF
MN...AND IN FACT HAS THE WAVE MOVE RIGHT ACROSS THE FORECAST AREA.
ADDITIONALLY...IN THE ECMWF...A SURGE OF 850MB MOISTURE TRANSPORT
ACCOMPANIES THE WAVE...HELPING TO PRODUCE SHOWERS AND STORMS ACROSS
MUCH OF THE AREA AND ESPECIALLY AFTER 06Z. NOW...THE 16.00Z GFS ALSO
DEPICTS AN INCREASE OF 850MB MOISTURE TRANSPORT AND PRECIPITATION...
BUT ITS MORE OVER NORTHWEST SECTIONS OF THE ARE AND IN RESPONSE TO
UPPER TROUGHING COMING INTO THE DAKOTAS. IN ANY EVENT...GIVEN THAT
THESE 2 MODELS ARE PRODUCING PRECIPITATION...FELT A NEED TO INCLUDE
20 PERCENT CHANCES IN FOR AT LEAST THE WEST HALF OF THE FORECAST
AREA. THESE MAY NEED TO BE INCREASED IF MODEL TRENDS CONTINUE.
MONDAY THROUGH TUESDAY...AND IN PARTICULARLY MONDAY NIGHT...STILL
REMAIN THE BEST CHANCE FOR WIDESPREAD RAIN. ALL MODELS ARE IN
AGREEMENT THAT THE CURRENT UPPER LOW OVER NORTHERN IDAHO...AND
ASSOCIATED GENERAL UPPER TROUGHING...WILL MOVE THROUGH THE FORECAST
AREA DURING THIS TIMEFRAME. A SURGE OF 1.5 INCH PRECIPITABLE WATER
COMBINED WITH DPVA FORCING FROM THE TROUGH...AS WELL AS INSTABILITY
SHOULD RESULT IN SHOWERS AND STORMS. MONDAY NIGHT SEEMS TO BE THE
BEST JUXTAPOSITION OF THE AFOREMENTIONED PARAMETERS AND THUS HIGHEST
CHANCES AROUND 70 PERCENT ARE CENTERED THERE. 0-6KM/0-3KM SHEAR
PROGGED LESS THAN 20 KT SO BRIEF HEAVY RAIN WOULD LIKELY BE THE MAIN
CONCERN WITH THE STORMS.
THE REST OF NEXT WEEK FEATURES THE UPPER LOW AND TROUGHING LIFTING
OUT OF THE REGION ON WEDNESDAY...FOLLOWED BY RIDGING BUILDING UP
ACROSS THE PLAINS AS TROUGHING REFORMS OVER THE PACIFIC NORTHWEST.
THIS SETUP IS FAVORABLE FOR BOTH WARM AND MOIST AIR ADVECTION...AND
AS SUCH MODELS CONTINUE TO OSCILLATE ON WHERE AND WHEN STORMS COULD
FIRE ON THE NOSE OF THIS ADVECTION. THEREFORE...FORECAST DEPICTS A
CONSENSUS WITH 20-40 PERCENT CHANCES FROM WEDNESDAY THROUGH FRIDAY.
THERE ARE SOME INDICATIONS WEDNESDAY COULD PAN OUT DRY...THUS LOWEST
CHANCES ARE CENTERED THEN. SEVERE WEATHER POTENTIAL WISE...IF THE
ECMWF PANS OUT...THERE COULD BE A SHOT FOR SOME ON THURSDAY. PLENTY
OF UNCERTAINTY OUT THERE...THOUGH. TEMPERATURES LOOK TO GRADUALLY
INCREASE EACH DAY WITH MOST DAYS AT OR ABOVE NORMAL. IT SHOULD BE
NOTED THAT IF ANY DAY ENDS UP WITH LESS CLOUDS...TEMPERATURES COULD
END UP WARMER THAN FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1130 AM CDT SAT AUG 16 2014
LOW STRATUS AND FOG SHOULD CONTINUE TO LIFT/BREAK UP EARLY THIS
AFTERNOON AS DAYTIME MIXING INCREASES. EXPECTING MORE STRATUS/FOG
DEVELOPMENT LATER TONIGHT...WITH SREF PROBABILITIES FAVORING THE
LOWER CIGS/VSBYS AT KRST. SUB 1 KFT CIGS LOOKS LIKELY AT BOTH
SITES...AND VSBYS COULD DROP BELOW 1SM AT KRST. WILL HOLD IN THE 1-
2SM RANGE FOR NOW. LOW STRATUS WILL HANG AROUND MOST OF THE MORNING
BEFORE MIXING CAN WORK ON LIFTING/BREAKING IT UP.
MEANWHILE...A COLD FRONT IS SLATED TO DROP SLOWLY SOUTH ACROSS WI/MN
TODAY/TONIGHT. NARROW REGION OF FRONTOGENETIC LIFT AROUND THE
BOUNDARY...AND IT WILL HAVE SOME DAYTIME INSTABILTY TO WORK ON.
EXPECTING SCATTERED SHRA/TS TO DEVELOP AROUND IT...MOSTLY WHEN
INSTABLITY IS AT ITS PEAK AND OVER WI. TO THE WEST...A WEAK
DISTURBANCE A LOFT WILL SPIN ACROSS THE PLAINS AND INTO MN TONIGHT.
THIS COULD WORK WITH THE FAR WESTERN REACHES OF THE FRONT TO SPARK A
FEW SHRA/TS. AT THIS TIME...THINK THE BETTER CHANCES WILL LIKE WEST
AND EAST OF KRST/KLSE...AND WILL LEAVE PCPN OUT OF THE FORECAST FOR
NOW. THAT SAID...IF IT BECOMES MORE LIKELY...IT WILL HAVE AN IMPACT
ON THE STRATUS/FOG POTENTIAL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
604 AM CDT SAT AUG 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT SAT AUG 16 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE SOUTHWESTERN U.S....AN UPPER LOW IN NORTHERN
IDAHO...SHORTWAVES OVER THE DAKOTAS AND THE KANSAS CITY AREA...AND A
DEEP UPPER TROUGH OVER EASTERN CANADA INTO THE NORTHEAST U.S..
WITHIN THIS TROUGH...A FAIRLY POTENT SHORTWAVE WAS APPROACHING LAKE
SUPERIOR. THE FORECAST AREA LIES IN THE NORTHWEST FLOW ON THE
WESTERN EDGE OF THE TROUGH...BUT STILL NEAR THE INFLECTION POINT
FAVORING SUBSIDENCE AND HIGH PRESSURE AT THE SURFACE. THUS...ONLY
SOME SCATTERED CIRRUS CLOUDS HAVE BEEN TRACKING ACROSS THE FORECAST
AREA. 15.00Z MODELS DEFINITELY OVER-FORECAST THE PRECIPITABLE
WATER...INSTEAD OF BEING 1.5-1.75 INCHES IS ONLY 1-1.25 INCHES PER
GOES DERIVED IMAGERY. SURFACE DEWPOINTS ARE HIGHER...THOUGH...WHICH
WITH RADIATIONAL COOLING HAS LED TO SOME BR AND LOW STRATUS
DEVELOPMENT. THE NEAREST AREAS WHERE PRECIPITATION IS OCCURRING ARE
SOUTH OF I-80 IN IOWA ASSOCIATED WITH THE KANSAS CITY SHORTWAVE...
OVER THE CENTRAL DAKOTAS WITH THE SHORTWAVE THERE...AND THE MN
ARROWHEAD INTO UPPER MICHIGAN AHEAD OF THE APPROACHING SHORTWAVE.
THIS LAST PRECIPITATION AREA IS ALSO SUPPORTED BY A SURFACE COLD
FRONT TRACKING WITH IT.
500MB HEIGHTS ARE PROGGED TO RISE OVER THE NEXT 24 HOURS IN RESPONSE
TO THE UPPER LOW OVER NORTHERN ONTARIO PUSHING EAST INTO SOUTH
CENTRAL SASKATCHEWAN. TYPICALLY WHEN SEEING HEIGHT RISES ONE WOULD
EXPECT A WARM ADVECTION PATTERN. HOWEVER...IN THIS CASE...THE
SHORTWAVE APPROACHING LAKE SUPERIOR WILL DROP INTO THE EASTERN GREAT
LAKES THIS EVENING...SENDING ITS ASSOCIATED COLD FRONT THROUGH THE
FORECAST AREA.
MUCH OF THIS MORNING CONTINUES TO LOOK DRY AS ANY SHOWER ACTIVITY
ASSOCIATED WITH THE KANSAS CITY SHORTWAVE STAYS JUST TO THE
SOUTH...AS DEPICTED IN THE LATEST RAP/HRRR DATA. ANY FOG/STRATUS
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNRISE. HEADING INTO THE
AFTERNOON...DETERMINISTIC AND HIGH RESOLUTION MODELS REMAIN IN GOOD
AGREEMENT THAT THIS COLD FRONT WILL HELP INITIATE CONVECTION NORTH
OF I-94. THIS IS A RESULT TOO OF TEMPERATURES CLIMBING INTO THE 80S
FROM 850MB TEMPS AROUND 16C...AS WELL AS DEWPOINTS CLIMBING INTO THE
MID TO UPPER 60S...COMBINING TO PRODUCE MLCAPES OF 1000-2000 J/KG.
THIS CAPE IS OVERALL SKINNY AND 0-6 KM/0-3KM SHEAR ARE 20 KT OR LESS
WHICH WILL LIMIT SEVERE WEATHER POTENTIAL. HOWEVER...EQUILIBRIUM
LEVELS ARE NEAR 40000 FT AND WARM CLOUD DEPTHS APPROACH 4000
METERS...SO THE STORMS ARE LIKELY TO PRODUCE HEAVY RAIN. THE AMOUNT
OF CONVECTION SEEMS SCATTERED AT BEST SINCE THE BETTER FRONTAL
CONVERGENCE AND DYNAMIC FORCING ARE FARTHER EAST...MORE TOWARDS
LOWER MICHIGAN CLOSER TO THE SHORTWAVE TRACK.
CONVECTION NORTH OF I-94 IN THE AFTERNOON THEN LOOKS TO DROP SOUTH
IN THE EVENING WITH THE COLD FRONT. HOWEVER...COOLING TEMPERATURES
FROM LOSS OF DAYTIME HEATING AND THE FACT LITTLE CONVERGENCE EXISTS
ON THE FRONT WILL LIKELY RESULT IN A DIMINISHING TREND TO THE
CONVECTION. THERE MAY NOT BE MUCH LEFT AFTER 06Z AS THE 16.00Z GFS
SUGGESTS. IN THE WAKE OF THE COLD FRONT...IT APPEARS A LOW STRATUS
DECK MAY END UP DEVELOPING AND ADVECTING SOUTHWESTWARD. BASED ON
FORECAST SOUNDINGS...LOCATIONS SOUTHWEST OF I-94 APPEAR TO HAVE THE
GREATEST CHANCE OF SEEING THIS STRATUS DECK. COOLING 925MB TEMPS ON
THE EASTERLY FLOW SHOULD RESULT IN A COOLER NIGHT...ESPECIALLY IN
CENTRAL WI.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 253 AM CDT SAT AUG 16 2014
MAIN ISSUE ON SUNDAY RELATES TO THE SHORTWAVE OVER THE DAKOTAS
CURRENTLY. THE 16.00Z GFS/NAM TRACK THIS SHORTWAVE ACROSS MN DURING
THE DAY...WHICH HELPS PRODUCE SOME SHOWERS AND EMBEDDED STORMS
MOSTLY JUST WEST OF THE FORECAST AREA. PART OF THE REASON THIS
PRECIPITATION DOESNT DEVELOP FARTHER EAST IS A DRY EASTERLY FLOW
PROVIDED BY HIGH PRESSURE BUILDING OVER UPPER MI IN THE WAKE OF
TONIGHTS COLD FRONT. ITS POSSIBLE SOME OF THE SHOWER ACTIVITY
CREEPS INTO SOUTHEAST MN...BUT CONFIDENCE IS NOT HIGH ENOUGH TO PUT
ANY CHANCES IN YET. OTHERWISE...SUNDAY LOOKS COOLER THAN TODAY DUE
TO THE EASTERLY FLOW...MORNING STRATUS AND 925MB TEMPS ABOUT 4C
COOLER.
SUNDAY NIGHT NOW POSES SOME FORECAST CHALLENGE. 16.00Z ECMWF IS
SLOWER THAN THE GFS/NAM TRACKING THE SHORTWAVE EASTWARD OUT OF
MN...AND IN FACT HAS THE WAVE MOVE RIGHT ACROSS THE FORECAST AREA.
ADDITIONALLY...IN THE ECMWF...A SURGE OF 850MB MOISTURE TRANSPORT
ACCOMPANIES THE WAVE...HELPING TO PRODUCE SHOWERS AND STORMS ACROSS
MUCH OF THE AREA AND ESPECIALLY AFTER 06Z. NOW...THE 16.00Z GFS ALSO
DEPICTS AN INCREASE OF 850MB MOISTURE TRANSPORT AND PRECIPITATION...
BUT ITS MORE OVER NORTHWEST SECTIONS OF THE ARE AND IN RESPONSE TO
UPPER TROUGHING COMING INTO THE DAKOTAS. IN ANY EVENT...GIVEN THAT
THESE 2 MODELS ARE PRODUCING PRECIPITATION...FELT A NEED TO INCLUDE
20 PERCENT CHANCES IN FOR AT LEAST THE WEST HALF OF THE FORECAST
AREA. THESE MAY NEED TO BE INCREASED IF MODEL TRENDS CONTINUE.
MONDAY THROUGH TUESDAY...AND IN PARTICULARLY MONDAY NIGHT...STILL
REMAIN THE BEST CHANCE FOR WIDESPREAD RAIN. ALL MODELS ARE IN
AGREEMENT THAT THE CURRENT UPPER LOW OVER NORTHERN IDAHO...AND
ASSOCIATED GENERAL UPPER TROUGHING...WILL MOVE THROUGH THE FORECAST
AREA DURING THIS TIMEFRAME. A SURGE OF 1.5 INCH PRECIPITABLE WATER
COMBINED WITH DPVA FORCING FROM THE TROUGH...AS WELL AS INSTABILITY
SHOULD RESULT IN SHOWERS AND STORMS. MONDAY NIGHT SEEMS TO BE THE
BEST JUXTAPOSITION OF THE AFOREMENTIONED PARAMETERS AND THUS HIGHEST
CHANCES AROUND 70 PERCENT ARE CENTERED THERE. 0-6KM/0-3KM SHEAR
PROGGED LESS THAN 20 KT SO BRIEF HEAVY RAIN WOULD LIKELY BE THE MAIN
CONCERN WITH THE STORMS.
THE REST OF NEXT WEEK FEATURES THE UPPER LOW AND TROUGHING LIFTING
OUT OF THE REGION ON WEDNESDAY...FOLLOWED BY RIDGING BUILDING UP
ACROSS THE PLAINS AS TROUGHING REFORMS OVER THE PACIFIC NORTHWEST.
THIS SETUP IS FAVORABLE FOR BOTH WARM AND MOIST AIR ADVECTION...AND
AS SUCH MODELS CONTINUE TO OSCILLATE ON WHERE AND WHEN STORMS COULD
FIRE ON THE NOSE OF THIS ADVECTION. THEREFORE...FORECAST DEPICTS A
CONSENSUS WITH 20-40 PERCENT CHANCES FROM WEDNESDAY THROUGH FRIDAY.
THERE ARE SOME INDICATIONS WEDNESDAY COULD PAN OUT DRY...THUS LOWEST
CHANCES ARE CENTERED THEN. SEVERE WEATHER POTENTIAL WISE...IF THE
ECMWF PANS OUT...THERE COULD BE A SHOT FOR SOME ON THURSDAY. PLENTY
OF UNCERTAINTY OUT THERE...THOUGH. TEMPERATURES LOOK TO GRADUALLY
INCREASE EACH DAY WITH MOST DAYS AT OR ABOVE NORMAL. IT SHOULD BE
NOTED THAT IF ANY DAY ENDS UP WITH LESS CLOUDS...TEMPERATURES COULD
END UP WARMER THAN FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 604 AM CDT SAT AUG 16 2014
LOW STRATUS AND FOG WILL IMPACT THE TAF SITES THROUGH 15Z THIS
MORNING WITH IFR/LIFR CONDITIONS EXPECTED. PLAN ON CEILINGS OF
800 FT AT KLSE. CEILINGS WILL BE LOWER AT TIMES AT KRST...FALLING
TO AROUND 500 FT. ALSO...VISIBILITY COULD BE REDUCED TO AROUND 2
SM AT KRST. THE FOG AND STRATUS WILL DISSIPATE AROUND 15Z AS
MIXING INCREASES WITH DAYTIME HEATING. A COLD FRONT IS EXPECTED TO
DROP SOUTH OUT OF NORTHERN WISCONSIN THIS AFTERNOON AND WILL HEAD
FOR THE TAF SITES THIS EVENING. SHOWERS AND THUNDERSTORMS ARE
POSSIBLE ALONG THE FRONT BUT LOOK TO STAY NORTH OF THE TAF SITES.
WILL HAVE TO KEEP A CLOSE EYE ON KLSE WHERE AN ISOLATED SHOWERS OR
THUNDERSTORM COULD OCCUR EARLY IN THE EVENING BEFORE INSTABILITY
WANES. MVFR/IFR CONDITIONS ARE EXPECTED LATE TONIGHT INTO SUNDAY
MORNING AS A STRATUS DECK MOVES INTO THE TAF SITES. KRST MAY SEE
SOME DENSE FOG AS WELL...MAINLY AFTER 08Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
253 AM CDT SAT AUG 16 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT SAT AUG 16 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE SOUTHWESTERN U.S....AN UPPER LOW IN NORTHERN
IDAHO...SHORTWAVES OVER THE DAKOTAS AND THE KANSAS CITY AREA...AND A
DEEP UPPER TROUGH OVER EASTERN CANADA INTO THE NORTHEAST U.S..
WITHIN THIS TROUGH...A FAIRLY POTENT SHORTWAVE WAS APPROACHING LAKE
SUPERIOR. THE FORECAST AREA LIES IN THE NORTHWEST FLOW ON THE
WESTERN EDGE OF THE TROUGH...BUT STILL NEAR THE INFLECTION POINT
FAVORING SUBSIDENCE AND HIGH PRESSURE AT THE SURFACE. THUS...ONLY
SOME SCATTERED CIRRUS CLOUDS HAVE BEEN TRACKING ACROSS THE FORECAST
AREA. 15.00Z MODELS DEFINITELY OVER-FORECAST THE PRECIPITABLE
WATER...INSTEAD OF BEING 1.5-1.75 INCHES IS ONLY 1-1.25 INCHES PER
GOES DERIVED IMAGERY. SURFACE DEWPOINTS ARE HIGHER...THOUGH...WHICH
WITH RADIATIONAL COOLING HAS LED TO SOME BR AND LOW STRATUS
DEVELOPMENT. THE NEAREST AREAS WHERE PRECIPITATION IS OCCURRING ARE
SOUTH OF I-80 IN IOWA ASSOCIATED WITH THE KANSAS CITY SHORTWAVE...
OVER THE CENTRAL DAKOTAS WITH THE SHORTWAVE THERE...AND THE MN
ARROWHEAD INTO UPPER MICHIGAN AHEAD OF THE APPROACHING SHORTWAVE.
THIS LAST PRECIPITATION AREA IS ALSO SUPPORTED BY A SURFACE COLD
FRONT TRACKING WITH IT.
500MB HEIGHTS ARE PROGGED TO RISE OVER THE NEXT 24 HOURS IN RESPONSE
TO THE UPPER LOW OVER NORTHERN ONTARIO PUSHING EAST INTO SOUTH
CENTRAL SASKATCHEWAN. TYPICALLY WHEN SEEING HEIGHT RISES ONE WOULD
EXPECT A WARM ADVECTION PATTERN. HOWEVER...IN THIS CASE...THE
SHORTWAVE APPROACHING LAKE SUPERIOR WILL DROP INTO THE EASTERN GREAT
LAKES THIS EVENING...SENDING ITS ASSOCIATED COLD FRONT THROUGH THE
FORECAST AREA.
MUCH OF THIS MORNING CONTINUES TO LOOK DRY AS ANY SHOWER ACTIVITY
ASSOCIATED WITH THE KANSAS CITY SHORTWAVE STAYS JUST TO THE
SOUTH...AS DEPICTED IN THE LATEST RAP/HRRR DATA. ANY FOG/STRATUS
SHOULD DISSIPATE WITHIN A FEW HOURS AFTER SUNRISE. HEADING INTO THE
AFTERNOON...DETERMINISTIC AND HIGH RESOLUTION MODELS REMAIN IN GOOD
AGREEMENT THAT THIS COLD FRONT WILL HELP INITIATE CONVECTION NORTH
OF I-94. THIS IS A RESULT TOO OF TEMPERATURES CLIMBING INTO THE 80S
FROM 850MB TEMPS AROUND 16C...AS WELL AS DEWPOINTS CLIMBING INTO THE
MID TO UPPER 60S...COMBINING TO PRODUCE MLCAPES OF 1000-2000 J/KG.
THIS CAPE IS OVERALL SKINNY AND 0-6 KM/0-3KM SHEAR ARE 20 KT OR LESS
WHICH WILL LIMIT SEVERE WEATHER POTENTIAL. HOWEVER...EQUILIBRIUM
LEVELS ARE NEAR 40000 FT AND WARM CLOUD DEPTHS APPROACH 4000
METERS...SO THE STORMS ARE LIKELY TO PRODUCE HEAVY RAIN. THE AMOUNT
OF CONVECTION SEEMS SCATTERED AT BEST SINCE THE BETTER FRONTAL
CONVERGENCE AND DYNAMIC FORCING ARE FARTHER EAST...MORE TOWARDS
LOWER MICHIGAN CLOSER TO THE SHORTWAVE TRACK.
CONVECTION NORTH OF I-94 IN THE AFTERNOON THEN LOOKS TO DROP SOUTH
IN THE EVENING WITH THE COLD FRONT. HOWEVER...COOLING TEMPERATURES
FROM LOSS OF DAYTIME HEATING AND THE FACT LITTLE CONVERGENCE EXISTS
ON THE FRONT WILL LIKELY RESULT IN A DIMINISHING TREND TO THE
CONVECTION. THERE MAY NOT BE MUCH LEFT AFTER 06Z AS THE 16.00Z GFS
SUGGESTS. IN THE WAKE OF THE COLD FRONT...IT APPEARS A LOW STRATUS
DECK MAY END UP DEVELOPING AND ADVECTING SOUTHWESTWARD. BASED ON
FORECAST SOUNDINGS...LOCATIONS SOUTHWEST OF I-94 APPEAR TO HAVE THE
GREATEST CHANCE OF SEEING THIS STRATUS DECK. COOLING 925MB TEMPS ON
THE EASTERLY FLOW SHOULD RESULT IN A COOLER NIGHT...ESPECIALLY IN
CENTRAL WI.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 253 AM CDT SAT AUG 16 2014
MAIN ISSUE ON SUNDAY RELATES TO THE SHORTWAVE OVER THE DAKOTAS
CURRENTLY. THE 16.00Z GFS/NAM TRACK THIS SHORTWAVE ACROSS MN DURING
THE DAY...WHICH HELPS PRODUCE SOME SHOWERS AND EMBEDDED STORMS
MOSTLY JUST WEST OF THE FORECAST AREA. PART OF THE REASON THIS
PRECIPITATION DOESNT DEVELOP FARTHER EAST IS A DRY EASTERLY FLOW
PROVIDED BY HIGH PRESSURE BUILDING OVER UPPER MI IN THE WAKE OF
TONIGHTS COLD FRONT. ITS POSSIBLE SOME OF THE SHOWER ACTIVITY
CREEPS INTO SOUTHEAST MN...BUT CONFIDENCE IS NOT HIGH ENOUGH TO PUT
ANY CHANCES IN YET. OTHERWISE...SUNDAY LOOKS COOLER THAN TODAY DUE
TO THE EASTERLY FLOW...MORNING STRATUS AND 925MB TEMPS ABOUT 4C
COOLER.
SUNDAY NIGHT NOW POSES SOME FORECAST CHALLENGE. 16.00Z ECMWF IS
SLOWER THAN THE GFS/NAM TRACKING THE SHORTWAVE EASTWARD OUT OF
MN...AND IN FACT HAS THE WAVE MOVE RIGHT ACROSS THE FORECAST AREA.
ADDITIONALLY...IN THE ECMWF...A SURGE OF 850MB MOISTURE TRANSPORT
ACCOMPANIES THE WAVE...HELPING TO PRODUCE SHOWERS AND STORMS ACROSS
MUCH OF THE AREA AND ESPECIALLY AFTER 06Z. NOW...THE 16.00Z GFS ALSO
DEPICTS AN INCREASE OF 850MB MOISTURE TRANSPORT AND PRECIPITATION...
BUT ITS MORE OVER NORTHWEST SECTIONS OF THE ARE AND IN RESPONSE TO
UPPER TROUGHING COMING INTO THE DAKOTAS. IN ANY EVENT...GIVEN THAT
THESE 2 MODELS ARE PRODUCING PRECIPITATION...FELT A NEED TO INCLUDE
20 PERCENT CHANCES IN FOR AT LEAST THE WEST HALF OF THE FORECAST
AREA. THESE MAY NEED TO BE INCREASED IF MODEL TRENDS CONTINUE.
MONDAY THROUGH TUESDAY...AND IN PARTICULARLY MONDAY NIGHT...STILL
REMAIN THE BEST CHANCE FOR WIDESPREAD RAIN. ALL MODELS ARE IN
AGREEMENT THAT THE CURRENT UPPER LOW OVER NORTHERN IDAHO...AND
ASSOCIATED GENERAL UPPER TROUGHING...WILL MOVE THROUGH THE FORECAST
AREA DURING THIS TIMEFRAME. A SURGE OF 1.5 INCH PRECIPITABLE WATER
COMBINED WITH DPVA FORCING FROM THE TROUGH...AS WELL AS INSTABILITY
SHOULD RESULT IN SHOWERS AND STORMS. MONDAY NIGHT SEEMS TO BE THE
BEST JUXTAPOSITION OF THE AFOREMENTIONED PARAMETERS AND THUS HIGHEST
CHANCES AROUND 70 PERCENT ARE CENTERED THERE. 0-6KM/0-3KM SHEAR
PROGGED LESS THAN 20 KT SO BRIEF HEAVY RAIN WOULD LIKELY BE THE MAIN
CONCERN WITH THE STORMS.
THE REST OF NEXT WEEK FEATURES THE UPPER LOW AND TROUGHING LIFTING
OUT OF THE REGION ON WEDNESDAY...FOLLOWED BY RIDGING BUILDING UP
ACROSS THE PLAINS AS TROUGHING REFORMS OVER THE PACIFIC NORTHWEST.
THIS SETUP IS FAVORABLE FOR BOTH WARM AND MOIST AIR ADVECTION...AND
AS SUCH MODELS CONTINUE TO OSCILLATE ON WHERE AND WHEN STORMS COULD
FIRE ON THE NOSE OF THIS ADVECTION. THEREFORE...FORECAST DEPICTS A
CONSENSUS WITH 20-40 PERCENT CHANCES FROM WEDNESDAY THROUGH FRIDAY.
THERE ARE SOME INDICATIONS WEDNESDAY COULD PAN OUT DRY...THUS LOWEST
CHANCES ARE CENTERED THEN. SEVERE WEATHER POTENTIAL WISE...IF THE
ECMWF PANS OUT...THERE COULD BE A SHOT FOR SOME ON THURSDAY. PLENTY
OF UNCERTAINTY OUT THERE...THOUGH. TEMPERATURES LOOK TO GRADUALLY
INCREASE EACH DAY WITH MOST DAYS AT OR ABOVE NORMAL. IT SHOULD BE
NOTED THAT IF ANY DAY ENDS UP WITH LESS CLOUDS...TEMPERATURES COULD
END UP WARMER THAN FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1144 PM CDT FRI AUG 15 2014
MAIN CONCERN CONTINUES TO BE WHETHER FOG WILL FORM OVERNIGHT. THE
HIGH LEVEL CLOUDS HAVE SHIFTED SOUTH OF THE AREA WHILE THE
MAJORITY OF THE CLOUDS APPROACHING FROM THE NORTH LOOK LIKE THEY
WILL GO EAST OF THE AREA. WINDS HAVE ALREADY GONE LIGHT SETTING UP
GOOD RADIATIONAL COOLING CONDITIONS. TEMP/DEW POINT DEPRESSIONS
FOR THE MOST PART ARE LESS THAN 5 DEGREES. THE 16.00Z NAM AND
16.03Z RAP CONTINUE TO SHOW A LAYER OF STRONGER WINDS ABOVE THE
SURFACE WHICH IS CONFIRMED BY AREA VWP WINDS. HOWEVER...THESE
MODELS NOW SUGGEST THESE WINDS WILL DIMINISH LATE TONIGHT SETTING
UP A SHORT PERIOD OF VERY FAVORABLE CONDITIONS FOR FOG. HAVE THUS
INCLUDED A PERIOD OF IFR CONDITIONS WITH THE FOG AT BOTH TAF SITES
FOR LATE TONIGHT INTO SATURDAY MORNING. ONCE THE FOG
LIFTS...EXPECT TO SEE VFR CONDITIONS FOR THE REMAINDER OF THE
PERIOD. THE COLD FRONT THAT COMES IN FROM THE NORTH SATURDAY
EVENING LOOKS TO HAVE LITTLE TO NO SUPPORT WITH IT WITH BOTH THE
NAM AND 16.00Z GFS SHOWING ONLY SOME HIGH LEVEL CLOUDS WITH IT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1144 PM CDT FRI AUG 15 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 341 PM CDT FRI AUG 15 2014
AT 3 PM...A BAND OF SHOWERS EXTENDED FROM SOUTH-CENTRAL IOWA
SOUTHEAST INTO SOUTHEAST IOWA. THIS IS ASSOCIATED WITH MODERATE TO
STRONG 900 TO 500 MB FRONTOGENETIC FORCING AND WEAK TO MODERATE
305K ISENTROPIC LIFT.
FOR TONIGHT...THE MESO AND DETERMINISTIC MODELS ARE IN GOOD
AGREEMENT THAT THE TROUGH OF LOW PRESSURE...CURRENTLY OVER EASTERN
SOUTH DAKOTA AND EASTERN NEBRASKA WILL MOVE EAST AND SOUTHEAST
THROUGH IOWA. THE MESO MODELS SHOW THAT THE MODERATE TO STRONG 900
TO 500 MB FRONTOGENESIS WILL REMAIN SOUTHWEST OF THE AREA THIS
EVENING...AND SOUTH OF THE AREA OVERNIGHT. AS A LOW DEVELOPS OVER
IOWA OVERNIGHT...THE 305K ISENTROPIC LIFT INCREASES DRAMATICALLY
ACROSS SOUTH-CENTRAL IOWA. THIS WILL LIKELY KEEP A MAJORITY OF
THE SHOWERS AND THUNDERSTORMS SOUTH OF THE AREA. HOWEVER WITH THE
NAM SOLUTIONS SUGGESTING A SLIGHTLY FURTHER NORTH TRACK OF THIS
SYSTEM KEPT A SLIGHT CHANCE OF PRECIPITATION IN FLOYD...
CHICKASAW...FAYETTE...AND CLAYTON COUNTIES IN NORTHEAST IOWA AND
GRANT COUNTY IN SOUTHWEST WISCONSIN BETWEEN 2 AM AND 10 AM
SATURDAY.
ANOTHER ISSUE FOR EARLY SATURDAY MORNING IS THE POTENTIAL FOR
AREAS OF FOG TO DEVELOP. BOTH THE NAM AND GFS BUFKIT SOUNDINGS
SHOW THAT THERE WILL BE A DRAMATIC INCREASE IN THE MOISTURE BELOW
925 MB AFTER 3 AM. THE WINDS IN THIS LAYER ARE LESS THAN 10 KNOTS
WHICH WOULD BE CONDUCIVE FOR THE DEVELOPMENT OF FOG. THE NUMERICAL
GUIDANCE SUGGESTS THAT THIS FOG COULD BECOME DENSE. ONE THING THAT
MIGHT DETER THE DENSE FOG DEVELOPMENT IS THE 10 TO 15 KNOT WINDS
BETWEEN 950 AND 900 MB. FOR THE TIME BEING...JUST ADDED AREAS OF
FOG TO THE GRIDS.
ON SATURDAY AFTERNOON...THE MODELS CONTINUE TO SHOW THAT A
CANADIAN COLD FRONT WILL MOVE SOUTH INTO NORTH-CENTRAL WISCONSIN
DURING THE MID TO LATE AFTERNOON. ML CAPES AHEAD OF THIS FRONT
CLIMB INTO THE 1000 TO 1500 J/KG RANGE. HOWEVER BOTH THE 0-3 KM
AND 0-6 KM SHEAR IS NOT THAT FAVORABLE FOR THE DEVELOPMENT OF
SEVERE WEATHER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 341 PM CDT FRI AUG 15 2014
ON SATURDAY EVENING...THE ML CAPES ALONG AND AHEAD OF COLD FRONT
MOVING THROUGH THE INTERSTATE 90 AND 94 CORRIDORS QUICKLY
DECREASES WITH THE LOSS OF DIURNAL HEATING. AS THIS OCCURS...THE
SHOWER AND THUNDERSTORM ACTIVITY WILL BECOME ISOLATED.
ON SUNDAY AND SUNDAY NIGHT...A CANADIAN HIGH PRESSURE WILL BRING
DRIER AIR INTO THE REGIONS. ORIGINALLY THE NAM KEPT THE DEW POINTS
IN THE LOWER AND MID 60S...BUT IT HAS NOW SHIFTED TOWARD THE DRIER
GFS AND ECMWF SOLUTIONS OF YESTERDAY. THE COMBINATION OF LIGHT
WINDS AND DEW POINTS IN THE MID AND UPPER 40S WILL ALLOW
TEMPERATURES TO ONCE AGAIN DROP INTO THE MID AND UPPER 40S ON
MONDAY MORNING. DUE TO THIS...WENT COLDER THAN THE SUPERBLEND.
FROM MONDAY AFTERNOON INTO TUESDAY NIGHT...THE 15.12Z MODELS
CONTINUE TO AGREE WITH PREVIOUS MODEL RUNS THAT A SHORT WAVE
TROUGH /THIS SYSTEM IS CURRENTLY LOCATED OVER THE PACIFIC
NORTHWEST/ WILL MOVE THROUGH THE REGION. WITH MODERATE 850 MB
MOISTURE TRANSPORT AHEAD OF THIS SYSTEM...THIS LOOKS TO BE OUR
BEST CHANCE FOR WIDESPREAD RAIN ACROSS THE AREA.
FROM WEDNESDAY INTO FRIDAY...THE MODELS CONTINUE TO STRUGGLE WITH
THE TIMING OF SHORT WAVE TROUGH MOVING THROUGH THE REGION. IN
ADDITION...THEY KEEP TRYING TO DEVELOP A TROUGH OVER THE WESTERN
UNITED STATES WHICH WOULD PRODUCE ZONAL OR SOUTHWEST FLOW ACROSS
OUR AREA. HOWEVER WITH THE ANOMALOUS WARM WATER LOCATED OFF THE
WEST COAST OF CANADA /LIKE MUCH OF LAST WINTER/...THE PATTERN THAT
THE MODELS ARE TRYING TO TREND TOWARD IS NOT THAT FAVORABLE...SO A
BIT LEARY OF THE GFS AND ECMWF SOLUTIONS DURING THIS TIME FRAME.
THIS INCLUDES THE VERY WARM TEMPERATURES THAT THESE MODELS ARE
INDICATING FOR THE END OF NEXT WEEK. A MORE FAVORABLE PATTERN
WOULD BE FOR A TROUGH OVER THE GREAT LAKES AND OHIO VALLEYS WHICH
WOULD KEEP US IN A NORTHWEST FLOW ALOFT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1144 PM CDT FRI AUG 15 2014
MAIN CONCERN CONTINUES TO BE WHETHER FOG WILL FORM OVERNIGHT. THE
HIGH LEVEL CLOUDS HAVE SHIFTED SOUTH OF THE AREA WHILE THE
MAJORITY OF THE CLOUDS APPROACHING FROM THE NORTH LOOK LIKE THEY
WILL GO EAST OF THE AREA. WINDS HAVE ALREADY GONE LIGHT SETTING UP
GOOD RADIATIONAL COOLING CONDITIONS. TEMP/DEW POINT DEPRESSIONS
FOR THE MOST PART ARE LESS THAN 5 DEGREES. THE 16.00Z NAM AND
16.03Z RAP CONTINUE TO SHOW A LAYER OF STRONGER WINDS ABOVE THE
SURFACE WHICH IS CONFIRMED BY AREA VWP WINDS. HOWEVER...THESE
MODELS NOW SUGGEST THESE WINDS WILL DIMINISH LATE TONIGHT SETTING
UP A SHORT PERIOD OF VERY FAVORABLE CONDITIONS FOR FOG. HAVE THUS
INCLUDED A PERIOD OF IFR CONDITIONS WITH THE FOG AT BOTH TAF SITES
FOR LATE TONIGHT INTO SATURDAY MORNING. ONCE THE FOG
LIFTS...EXPECT TO SEE VFR CONDITIONS FOR THE REMAINDER OF THE
PERIOD. THE COLD FRONT THAT COMES IN FROM THE NORTH SATURDAY
EVENING LOOKS TO HAVE LITTLE TO NO SUPPORT WITH IT WITH BOTH THE
NAM AND 16.00Z GFS SHOWING ONLY SOME HIGH LEVEL CLOUDS WITH IT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
905 PM MDT SUN AUG 17 2014
.UPDATE...
ISSUED AT 905 PM MDT SUN AUG 17 2014
THE EARLIER CRITICAL FIRE WEATHER CONDITIONS HAVE IMPROVED
DRAMATICALLY OVER THE PAST FEW HOURS. SO...IN AN EARLIER
UPDATE LET THE HIGHLIGHT EXPIRE AS SCHEDULED. OTHERWISE...THE
PESKY HIGH-BASED CONVECTION THAT PRODUCED GUSTS OF 55-60 MPH AT A
FEW OBSERVATION SITES EARLIER THIS EVENING...HAVE ALL DISSIPATED
WITH LOSS OF HEATING THIS EVENING. INITIAL LOOKS AT 00Z CONTINUES
TO SUPPORT THE IDEA OF ISOLATED CONVECTION LATE TOMORROW
AFTERNOON...PRIMARILY OVER THE SE WYOMING PLAINS. THE 00Z NAM
TARGETS LARAMIE COUNTY AS HAVING THE BEST CHANCE. WILL SEE WHAT
THE 00Z GFS SUGGESTS BEFORE MAKING ANY CHANGES TO THE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 330 PM MDT SUN AUG 17 2014
AFTERNOON WATER VAPOR LOOP REVEALED A CLOSED UPPER LOW NORTH OF THE
NORTH DAKOTA BORDER WITH A TROUGH AXIS INTO THE WESTERN DAKOTAS.
CLUSTERS OF INTENSE CONVECTION WERE DEVELOPING AHEAD OF THIS FEATURE.
CYS/RIW RADARS SHOWED A FEW SHOWERS DEVELOPING ALONG A WEAK
CONVERGENCE ZONE FROM SOUTHERN NATRONA TO SOUTHERN CONVERSE COUNTY.
THE HRRR MODEL COMPOSITE REFLECTIVITY LOOP SHOWED THIS ACTIVITY
MOVING ACROSS EAST CENTRAL WYOMING THROUGH LATE AFTERNOON THEN
DISSIPATING. WITH VERY DRY SUB-CLOUD LAYER...CAN EXPECT GUSTY WINDS
AND LITTLE IF ANY MEASURABLE RAINFALL WITH THESE SHOWERS. MAIN
CONCERN CONTINUES TO BE FIRE WEATHER IMPACTS FROM THE GUSTY WINDS
AND LOW HUMIDITY FOR ELEVATIONS BELOW 8000 FT. RED FLAG WARNING
REMAINS IN EFFECT FOR ALL BUT THE SIERRA MADRE/SNOWY RANGE ZONES
THROUGH 7 PM. GETTING CLOSE TO RED FLAG CRITERIA OVER THE NEBRASKA
PANHANDLE ZONES BORDERING WYOMING. CONDITIONS WILL IMPROVE THIS
EVENING AS WINDS DECREASE AND HUMIDITIES INCREASE.
A BLEND OF THE 12Z SHORT RANGE MODEL GUIDANCE HANDLES THE LARGE SCALE
PATTERN PRETTY WELL. THE UPPER TROUGH ADVANCES EAST SOUTHEAST ACROSS
THE DAKOTAS AND MIDWEST DURING THE NEXT 24 HOURS. MEANWHILE...A UPPER
RIDGE EXPANDS NORTHWEST FROM THE FOUR CORNERS REGION WITH A HEALTHY
SURGE OF SUBTROPICAL MOISTURE MOVING INTO THE CENTRAL ROCKIES
TUESDAY. PRECIP WATER VALUES MONDAY WILL RANGE FROM A HALF INCH WEST
OF THE LARAMIE RANGE TO AROUND AN INCH FOR THE HIGH PLAINS.
TUESDAY...PRECIP WATER INCREASE TO AROUND 1.25 INCHES EAST OF THE
LARAMIE AND 0.75-1.0 INCH TO THE WEST. DIURNAL CONVECTIVE COVERAGE
MONDAY WILL BE ISOLATED AND CONFINED TO THE MOUNTAINS. THE AIRMASS
OVER THE PLAINS WILL REMAIN CAPPED PRECLUDING SHOWER DEVELOPMENT.
SHOWER/TSTORM COVERAGE INCREASES TO SCATTERED TUESDAY
AFTERNOON/EVENING AS A POTENT SHORTWAVE RIDES NORTHEAST ACROSS
WYOMING AND COLORADO. DOWNSLOPING WESTERLY WINDS WILL LIMIT QPF OVER
THE EASTERN WYOMING PLAINS...WITH AT LEAST O.25 INCH AMOUNTS
POSSIBLE OVER THE HIGHER TERRAIN AND WESTERN NEBRASKA PANHANDLE.
ABOVE NORMAL WARMTH WILL CONTINUE MONDAY LOWER ELEVATIONS MONDAY AND
EAST OF THE LARAMIE RANGE TUESDAY WITH HIGHS IN THE 80S TO LOWER 90S.
TEMPERATURES WILL TREND SLIGHTLY COOLER WEST OF THE LARAMIE RANGE
TUESDAY DUE TO GREATER CLOUD AND SHOWER COVERAGE.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 17 2014
WARM AND MAINLY DRY WEATHER EXPECTED ACROSS THE CWA WEDNESDAY AND
THURSDAY THOUGH A FEW SHOWERS/TSTRMS POSSIBLE OVER THE HIGHER SRN
MTNS BOTH AFTERNOONS/EARLY EVENINGS. CHANGES LOOK TO BE IN THE
OFFING BEGINNING FRIDAY AND CONTINUING INTO THE WEEKEND AS AN
UPPER TROF SETTLES OVER THE NW PART OF THE COUNTRY AND A PUSH OF
COOLER CANADIAN AIR DROPS DOWN THE HIGH PLAINS SATURDAY AND
SATURDAY NIGHT WITH THE EC CONTINUING TO BE MUCH MORE BULLISH IN
PUSHING THIS COOL AIR ACROSS THE CWA BY LATE SATURDAY...SETTING UP
A MILD DAY FOR SUNDAY. EC HAS BEEN CONSISTENT WITH THIS. SHOULD
ALSO SEE A BIT OF AN UPTICK IN CONVECTION FRIDAY AND SATURDAY AS
THE UPPER TROF NEARS WITH ANY ASSOCIATED IMPULSES ROUNDING THE
BASE OF IT PASSING ACROSS THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH NOON MONDAY)
ISSUED AT 529 PM MDT SUN AUG 17 2014
VFR CONDITIONS THROUGH TONIGHT AND INTO EARLY MONDAY WITH A DRY AIR
MASS OVER MOST OF THE AREA. CURRENTLY WATCHING AN AREA OF TSTORMS
SOUTH OF RAPID CITY...PUSHING SOUTHEAST TOWARDS NEBRASKA. THIS AREA
OF THUNDERSTORMS SHOULD REMAIN EAST OF KCDR AND KAIA THIS
EVENING...SO KEPT VCTS OUT OF THE TAF FOR NOW. OTHERWISE...A WEAK
SURFACE COOL FRONT WILL MOVE SOUTH ACROSS WY AND NEBRASKA TONIGHT
RESULTING IN WINDS SHIFTING INTO THE NORTH BUT REMAINING LIGHT.
THERE IS A HIGHER CHANCE OF SHOWERS AND TSTORMS MONDAY AFTERNOON
ACROSS SOUTHEAST WYOMING...MAINLY IN THE MOUNTAINS.
&&
.FIRE WEATHER...
ISSUED AT 703 PM MDT SUN AUG 17 2014
CONDITIONS WILL CONTINUE TO IMPROVE ACROSS THE DISTRICTS THROUGH
THE REST OF THE EVENING. THEREFORE...ALLOWED THE RED FLAG WARNING
TO EXPIRE AT 7 PM.
FIRE WEATHER CONCERNS WILL BECOME MINIMAL MONDAY AND TUESDAY AS AN
INFLUX OF MONSOON MOISTURE FROM THE SOUTHWEST INCREASES CHANCES
FOR WETTING RAINS EARLY THIS WEEK. WINDS WILL BE LIGHTER AS WELL.
DRIER CONDITIONS RETURN MID WEEK FOLLOWED BY A SLIGHT INCREASE IN
MOISTURE LATE IN THE WEEK. ABOVE AVERAGE TEMPERATURES THIS WEEK
WILL GRADUALLY COOL NEXT WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...HAHN
SHORT TERM...JAMSKI
LONG TERM...RE
AVIATION...TJT
FIRE WEATHER...JAMSKI
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
530 PM MDT SUN AUG 17 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 330 PM MDT SUN AUG 17 2014
AFTERNOON WATER VAPOR LOOP REVEALED A CLOSED UPPER LOW NORTH OF THE
NORTH DAKOTA BORDER WITH A TROUGH AXIS INTO THE WESTERN DAKOTAS.
CLUSTERS OF INTENSE CONVECTION WERE DEVELOPING AHEAD OF THIS FEATURE.
CYS/RIW RADARS SHOWED A FEW SHOWERS DEVELOPING ALONG A WEAK
CONVERGENCE ZONE FROM SOUTHERN NATRONA TO SOUTHERN CONVERSE COUNTY.
THE HRRR MODEL COMPOSITE REFLECTIVITY LOOP SHOWED THIS ACTIVITY
MOVING ACROSS EAST CENTRAL WYOMING THROUGH LATE AFTERNOON THEN
DISSIPATING. WITH VERY DRY SUB-CLOUD LAYER...CAN EXPECT GUSTY WINDS
AND LITTLE IF ANY MEASURABLE RAINFALL WITH THESE SHOWERS. MAIN
CONCERN CONTINUES TO BE FIRE WEATHER IMPACTS FROM THE GUSTY WINDS
AND LOW HUMIDITY FOR ELEVATIONS BELOW 8000 FT. RED FLAG WARNING
REMAINS IN EFFECT FOR ALL BUT THE SIERRA MADRE/SNOWY RANGE ZONES
THROUGH 7 PM. GETTING CLOSE TO RED FLAG CRITERIA OVER THE NEBRASKA
PANHANDLE ZONES BORDERING WYOMING. CONDITIONS WILL IMPROVE THIS
EVENING AS WINDS DECREASE AND HUMIDITIES INCREASE.
A BLEND OF THE 12Z SHORT RANGE MODEL GUIDANCE HANDLES THE LARGE SCALE
PATTERN PRETTY WELL. THE UPPER TROUGH ADVANCES EAST SOUTHEAST ACROSS
THE DAKOTAS AND MIDWEST DURING THE NEXT 24 HOURS. MEANWHILE...A UPPER
RIDGE EXPANDS NORTHWEST FROM THE FOUR CORNERS REGION WITH A HEALTHY
SURGE OF SUBTROPICAL MOISTURE MOVING INTO THE CENTRAL ROCKIES
TUESDAY. PRECIP WATER VALUES MONDAY WILL RANGE FROM A HALF INCH WEST
OF THE LARAMIE RANGE TO AROUND AN INCH FOR THE HIGH PLAINS.
TUESDAY...PRECIP WATER INCREASE TO AROUND 1.25 INCHES EAST OF THE
LARAMIE AND 0.75-1.0 INCH TO THE WEST. DIURNAL CONVECTIVE COVERAGE
MONDAY WILL BE ISOLATED AND CONFINED TO THE MOUNTAINS. THE AIRMASS
OVER THE PLAINS WILL REMAIN CAPPED PRECLUDING SHOWER DEVELOPMENT.
SHOWER/TSTORM COVERAGE INCREASES TO SCATTERED TUESDAY
AFTERNOON/EVENING AS A POTENT SHORTWAVE RIDES NORTHEAST ACROSS
WYOMING AND COLORADO. DOWNSLOPING WESTERLY WINDS WILL LIMIT QPF OVER
THE EASTERN WYOMING PLAINS...WITH AT LEAST O.25 INCH AMOUNTS
POSSIBLE OVER THE HIGHER TERRAIN AND WESTERN NEBRASKA PANHANDLE.
ABOVE NORMAL WARMTH WILL CONTINUE MONDAY LOWER ELEVATIONS MONDAY AND
EAST OF THE LARAMIE RANGE TUESDAY WITH HIGHS IN THE 80S TO LOWER 90S.
TEMPERATURES WILL TREND SLIGHTLY COOLER WEST OF THE LARAMIE RANGE
TUESDAY DUE TO GREATER CLOUD AND SHOWER COVERAGE.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 17 2014
WARM AND MAINLY DRY WEATHER EXPECTED ACROSS THE CWA WEDNESDAY AND
THURSDAY THOUGH A FEW SHOWERS/TSTRMS POSSIBLE OVER THE HIGHER SRN
MTNS BOTH AFTERNOONS/EARLY EVENINGS. CHANGES LOOK TO BE IN THE
OFFING BEGINNING FRIDAY AND CONTINUING INTO THE WEEKEND AS AN
UPPER TROF SETTLES OVER THE NW PART OF THE COUNTRY AND A PUSH OF
COOLER CANADIAN AIR DROPS DOWN THE HIGH PLAINS SATURDAY AND
SATURDAY NIGHT WITH THE EC CONTINUING TO BE MUCH MORE BULLISH IN
PUSHING THIS COOL AIR ACROSS THE CWA BY LATE SATURDAY...SETTING UP
A MILD DAY FOR SUNDAY. EC HAS BEEN CONSISTENT WITH THIS. SHOULD
ALSO SEE A BIT OF AN UPTICK IN CONVECTION FRIDAY AND SATURDAY AS
THE UPPER TROF NEARS WITH ANY ASSOCIATED IMPULSES ROUNDING THE
BASE OF IT PASSING ACROSS THE AREA.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH NOON MONDAY)
ISSUED AT 529 PM MDT SUN AUG 17 2014
VFR CONDITIONS THROUGH TONIGHT AND INTO EARLY MONDAY WITH A DRY AIR
MASS OVER MOST OF THE AREA. CURRENTLY WATCHING AN AREA OF TSTORMS
SOUTH OF RAPID CITY...PUSHING SOUTHEAST TOWARDS NEBRASKA. THIS AREA
OF THUNDERSTORMS SHOULD REMAIN EAST OF KCDR AND KAIA THIS
EVENING...SO KEPT VCTS OUT OF THE TAF FOR NOW. OTHERWISE...A WEAK
SURFACE COOL FRONT WILL MOVE SOUTH ACROSS WY AND NEBRASKA TONIGHT
RESULTING IN WINDS SHIFTING INTO THE NORTH BUT REMAINING LIGHT.
THERE IS A HIGHER CHANCE OF SHOWERS AND TSTORMS MONDAY AFTERNOON
ACROSS SOUTHEAST WYOMING...MAINLY IN THE MOUNTAINS.
&&
.FIRE WEATHER...
ISSUED AT 220 PM MDT SUN AUG 17 2014
NORTHWEST WINDS GUSTS OF 25 TO 35 MPH COMBINED WITH RELATIVE
HUMIDITIES OF 10 TO 15 PERCENT WILL CREATE CONDITIONS CONDUCIVE TO
RAPID FIRE GROWTH FOR AREAS BELOW 8000 FEET IN SOUTHEAST WYOMING
THROUGH EARLY EVENING. GUSTS APPROACHING 25 MPH AND 10 TO 15 PERCENT
HUMIDITIES OVER THE FAR WESTERN NEBRASKA PANHANDLE WILL ENHANCE THE
FIRE WEATHER THREAT THIS AFTERNOON. FIRE WEATHER CONCERNS WILL
BECOME MINIMAL MONDAY AND TUESDAY AS AN INFLUX OF MONSOON MOISTURE
FROM THE SOUTHWEST INCREASES CHANCES FOR WETTING RAINS EARLY THIS
WEEK. WINDS WILL BE LIGHTER AS WELL. DRIER CONDITIONS RETURN MID
WEEK FOLLOWED BY A SLIGHT INCREASE IN MOISTURE LATE IN THE WEEK.
ABOVE AVERAGE TEMPERATURES THIS WEEK WILL GRADUALLY COOL NEXT
WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR WYZ301>304-306-
308>310.
NE...NONE.
&&
$$
SHORT TERM...JAMSKI
LONG TERM...RE
AVIATION...TJT
FIRE WEATHER...JAMSKI
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
215 AM MST MON AUG 18 2014
.SYNOPSIS...
AN EARLY SEASON PACIFIC LOW PRESSURE SYSTEM WILL APPROACH THE AREA
TODAY...AND WILL DRAW EVEN MORE MONSOON MOISTURE NORTHWARD BACK INTO
ARIZONA. MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS
EXPECTED ACROSS ARIZONA FROM LATE TONIGHT THROUGH MUCH OF THIS WEEK.
WITH THE INCREASE IN HUMIDITIES AND CLOUDS...BELOW NORMAL
TEMPERATURES ARE POSSIBLE BY TUESDAY AND WILL LIKELY CONTINUE
THROUGH THE REMAINDER OF THE WORKWEEK.
&&
.DISCUSSION...
TODAY THROUGH WEDNESDAY...
THERE IS NOW EXCELLENT MODEL AGREEMENT ON THE FORECAST FOR OUR CWA
THROUGH WEDNESDAY. BOTH THE GFS AND EURO ARE TRACKING A RATHER
VIGOROUS UPPER LOW CENTER SOUTHWARD ALONG THE CA COAST DURING THIS
PERIOD...WITH INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW AHEAD OF
THIS LOW CENTER PULLING ADDITIONAL MOISTURE NORTHWARD INTO THE
REGION. A REFLECTION OF THIS MOISTURE...A VERY LARGE THUNDERSTORM
COMPLEX CAN BEEN SEEN ON IR AND WATER VAPOR IMAGERY THIS MORNING
OVER EXTREME NORTHWEST SONORA MEXICO...JUST SOUTH OF THE
INTERNATIONAL BORDER. OUTFLOWS FROM THE TS COMPLEX WILL LIKELY PUSH
SFC DEWPOINTS EVEN HIGHER OVER SOUTHWEST AZ THIS MORNING...PROVIDING
THE FUEL FOR TS DEVELOPMENT LATER THIS AFTERNOON. THE LATEST HRRR IS
NOW SHOWING...AFTER A BIT OF A BREAK LATER THIS MORNING AND EARLY
AFTERNOON...WHICH WILL THE ATMOSPHERE A CHANCE TO RELOAD AFTER BEING
WORKED OVER BY LAST NIGHT`S CONVECTIVE ACTIVITY...THUNDERSTORMS
REBUILDING OVER THE HIGHER TERRAIN NORTH AND EAST OF PHX AND OVER SE
AZ...THEN BEGIN TO MOVE THEM INTO THE LOWER ELEVATIONS BY LATE
AFTERNOON AND EARLY EVENING. ONCE AGAIN...THE MAIN IMPACTS FROM
THESE STORMS WILL BE GUSTY WINDS/LOCALIZED BLOWING DUST/BRIEF HEAVY
DOWNPOURS.
SHOWER/TS ACTIVITY WILL LIKELY CONTINUE WELL INTO TONIGHT AND INTO
TUESDAY...ESPECIALLY OVER SOUTH-CENTRAL AND SW AZ AS PWATS RISE INTO
THE 1.80-2.00 INCH RANGE...AND UPPER-LEVEL DIFLUENCE DEVELOPS OVER
THE REGION. HEAVY RAIN/LOCALIZED FLOODING WILL LIKELY BE THE MAIN
ISSUE WITH STORMS LATER TONIGHT AND TUESDAY AS THE VERY MOIST
AIRMASS WILL MAKE THEM MORE EFFICIENT RAINFALL PRODUCERS...WITH
LOCALIZED RAINFALL AMOUNTS AOA 1 INCH LIKELY IN A FEW SPOTS. THE
WIDESPREAD RAINFALL/CLOUDINESS IS EXPECTED TO PUSH HIGH TEMPS ON
TUESDAY BACK BELOW NORMAL...WITH MANY LOWER DESERT LOCATIONS ACROSS
SOUTH-CENTRAL AZ REMAINING BELOW 100F.
A BIT OF A BREAK IS LIKELY ON WEDNESDAY AS THE MAIN MOISTURE PLUME
IS PUSHED TO THE SOUTH AND EAST BY THE APPROACHING UPPER LOW CENTER
AS IT PUSHES INLAND OVER SOUTHERN CA...BUT SCATTERED THUNDERSTORMS
ARE STILL LIKELY TO DEVELOP OVER THE HIGHER TERRAIN NORTH AND EAST
OF PHOENIX.
THURSDAY THROUGH SATURDAY...
SOME MODEL CONSENSUS IS FINALLY BEGINNING TO SHOW UP DURING THIS
PERIOD. THE EURO IS NOW BEGINNING TO SIDE WITH THE GFS...BY TAKING
THE MAIN UPPER LOW CENTER INLAND INTO AZ/NM...WITH CONSIDERABLE
TROPICAL MOISTURE FROM THE REMAINS OF TROPICAL CYCLONE 12E...WHICH
HAS NOW FORMED WELL SOUTHWEST OF THE TIP OF BAJA CALIFORNIA...MOVING
INTO THE DESERT SOUTHWEST AHEAD OF THIS LOW CENTER. THERE IS STILL
CONSIDERABLE TIMING DIFFERENCES BETWEEN THE TWO MODELS...WITH THE
GFS MOVING THE UPPER LOW CENTER INTO AZ LATE THU NIGHT/EARLY
FRIDAY...WHILE THE MUCH SLOWER EURO MOVES IT INTO AZ ON SATURDAY.
EITHER WAY...IT APPEARS MORE-AND-MORE LIKELY THAT A SIGNIFICANT
RAINFALL EVENT COULD DEVELOP OVER AZ...WITH TEMPS FALLING WELL BELOW
NORMAL...WHICH IS VERY UNUSUAL IN MID-LATE AUGUST. THUS...HAVE
RAISED POPS ACROSS THE BOARD DURING THIS PERIOD.
SUNDAY AND MONDAY...
A RETURN TO A MUCH DRIER...AND WARMER PATTERN IS EXPECTED DURING
THIS PERIOD AS BOTH THE GFS AND EURO BEGIN TO DIG A BROAD LONG-WAVE
TROF SOUTHWARD INTO THE INTERMOUNTAIN WEST...WITH WESTERLY FLOW
ALOFT ADVECTING MUCH DRIER AIR INTO THE REGION.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
CONVECTION SLOWLY DYING OFF ACROSS THE AREA AND CONDITIONS SHOULD
CONTINUE TO IMPROVE FOR THE REST OF THE EVENING/OVERNIGHT HOURS.
EXPECT BREEZY EAST WINDS TO GRADUALLY WEAKEN OVERNIGHT BUT RETAIN
THEIR EASTERLY COMPONENT THROUGH LATE MORNING. CONVECTION POSSIBLE
ONCE AGAIN ACROSS THE AREA MONDAY AFTERNOON ESPECIALLY LATE IN THE
TAF PERIOD.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
STORMS HAVE BEEN CONFINED TO ARIZONA THIS EVENING BUT OUTFLOWS WILL
LIKELY MAKE THEIR WAY INTO BLH AFTER 06Z. MEANWHILE STORMS OVER
SONORA ARE MAKING A PUSH TOWARD THE REGION AND COULD REDEVELOP OVER
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA LATE TONIGHT/EARLY MONDAY
MORNING. CONFIDENCE IN THIS SOLUTION IS VERY LOW BUT I WILL MAKE A
MENTION OF VCSH IN BOTH TAFS AROUND 12Z. PRIMARY THREATS WILL BE
GUSTY WINDS AND REDUCED VSBYS. STORMS POSSIBLE ONCE AGAIN MONDAY
AFTERNOON.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
DEEP MONSOON MOISTURE WILL CONTINUE THIS PERIOD WITH HIGHER THAN
NORMAL RELATIVE HUMIDITY. A GOOD CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS ARE EXPECTED OVER HIGHER MOUNTAINS OF SOUTHERN GILA
COUNTY EACH DAY...WITH A SLIGHT CHANCE OF THUNDERSTORMS ON THE LOWER
SOUTHWEST AND SOUTH CENTRAL DESERTS. MINIMUM RELATIVE HUMIDITIES WILL
RANGE FROM 25 TO 30 PERCENT. OVERNIGHT RECOVERY WILL BE FAIR.
AFTERNOON TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL THIS PERIOD.
ADDITIONALLY...AFTERNOON/EARLY EVENING WINDS WILL BE SOUTHWESTERLY
AND GENERALLY UNDER 20 MPH...EXCEPT NEAR THUNDERSTORMS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA
AVIATION...LEINS
FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1101 PM MDT SUN AUG 17 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 252 PM MDT SUN AUG 17 2014
AN UPR RIDGE WL REMAIN CENTERED NR THE FOUR CORNERS THRU
TONIGHT...SHIFTING A LITTLE EASTWARD ON MON. THIS AFTERNOON A WEAK
DISTURBANCE IS MOVING ACRS NRN CO. SOME ISOLD THUNDERSTORMS HAVE
DEVELOPED OVR SOME OF THE MTN AREAS AND OVER THE EAST CENTRAL
PLAINS. EXPECTING MORE DEVELOPMENT OVR THE MTNS THE REST OF THIS
AFTERNOON...WITH SOME ISOLD DEVELOPMENT OVR PORTIONS OF THE SERN
PLAINS. BOTH THE RAP AND HRRR CONTINUE TO SHOW AN AREA OF TSTMS
DEVELOPING THIS AFTERNOON...ASSOCIATED WITH THE WX DISTURBANCE...
OVER THE PIKES PEAK REGION AND THEN MOVING SOUTHEASTWARD ACRS THE
SERN PLAINS THRU THE EVENING HOURS...AND DISSIPATING OR EXITING
THE SERN CORNER OF THE STATE BY ABOUT 1 OR 2 AM.
ON MONDAY AN UPR TROF MOVES INTO WRN NV AND SHIFT THE UPR RIDGE
CENTER A LITTLE EASTWARD OVR CO. PRECIPITABLE WATER VALUES ACRS THE
FORECAST AREA ARE EXPECTED TO BE SIMILAR TO TODAY. EXPECTING SOME
SHOWERS/TSTM DEVELOPMENT OVR SOME OF THE MTN AREAS IN THE LATE
MORNING HOURS AGAIN. THEN INCREASING IN COVERAGE IN THE AFTERNOON
HOURS OVER THE MTNS AND HIGH VALLEYS...WITH SOME ISOLD STORMS
DEVELOPING OVR MOVING OVR THE SOUTHEAST PLAINS. HIGH TEMPS ON MON
WL AGAIN BE ABOVE AVERAGE BY AROUND 5 DEGREES.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 252 PM MDT SUN AUG 17 2014
...MORE MONSOON NEXT WEEK...
EXTENDED FORECAST CONTINUES TO BE A BIT SHAKY AS THE GLOBAL
MODEL RUNS STRUGGLE WITH FAIRLY COMPLEX INTERACTIONS INVOLVING
THE POLAR JET TO THE NORTH AND A SUBTROPICAL INFLUENCE TO THE
SOUTH. THE EC AND GFS ARE IN REASONABLE AGREEMENT THROUGH ABOUT
TUESDAY...THEN THE CONSISTENCY STARTS TO UNRAVEL.
A PACIFIC TROUGH WILL AMPLIFY ON TUESDAY AND BEGIN MOVING INTO
THE PACNW...AS A CUTOFF LOW DRIFTS OFF THE CA COAST. INCREASED
S-SW FLOW ALOFT WILL BRING MOISTURE UP FROM MEXICO AND THE DESERT
SW INTO WRN CO. THE ECMWF SEEMS TO BE OVERDOING QPF E OF THE
MTS...WHILE THE GFS AND NAM ARE MORE REALISTIC IN DEPICTING
MOSTLY DRY CONDITIONS FOR THE PLAINS BUT PLENTY OF MOISTURE
FOR THE MTN AREAS. TEMPS WILL START TO MODERATE FOR MOST OF OUR
CWA AND SHOULD BE CLOSE TO AVERAGE.
THE LATEST GFS HAS A STRONGER OR MORE AMPLIFIED NRN TROUGH...AND
ALSO SHOWS BETTER PHASING WITH THE CA CUT-OFF LOW. IT ALSO HINTS
AT AT LEAST A POTENTIAL MOISTURE TAP FROM A TROPICAL SYSTEM THAT
WILL BE MOVING NWD...WELL OFF OF THE BAJA PENINSULA. THE EC HAS A
WEAKER NRN SYSTEM AND RETROGRADES THE UPPER LOW AND TROPICAL
SYSTEM OFF THE CA COAST...WITH LESS OF A MOISTURE FLUX INTO CO.
BASED ON THE PATTERN AND ENSEMBLE TRENDS...IT APPEARS LIKELY THAT
AN AMPLIFIED PACIFIC SYSTEM WILL MOVE INTO THE NRN ROCKIES FOR THE
LATTER PART OF NEXT WEEK INTO NEXT WEEKEND. HAVE BOOSTED POPS FROM
WED ONWARD BY 5-10 PERCENT TO ACCOUNT FOR THAT LIKELIHOOD...AND
LATER SHIFTS MAY HAVE TO CONTINUE THAT TREND IF THE DEEPER SYSTEM
ENDS UP LOOKING MORE LIKELY. WILL HAVE TO KEEP A CLOSE EYE ON
TRENDS...SINCE THE LONG RANGE GFS HINTS AT SIGNIFICANT RAINFALL
POSSIBLE ON THE BACKSIDE OF THIS NRN BRANCH SYSTEM...BY THE LAST
WEEK IN AUGUST. ROSE
&&
.AVIATION...ISSUED AT 1101 PM MDT SUN AUG 17 2014
THE KALS...KCOS AND KPUB TAF SITES SHOULD EXPERIENCE VFR
CONDITIONS THROUGH TONIGHT.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
420 AM EDT MON AUG 18 2014
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL REMAIN SOUTHEAST OF THE REGION THROUGH FRIDAY
WITH A TROUGH OF LOW PRESSURE INLAND. A COLD FRONT WILL DROP THROUGH
THE AREA OVER THE WEEKEND WITH HIGH PRESSURE BUILDING IN FROM THE NORTH
INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
PRE-DAWN...DEEP LAYERED MOISTURE HAS BEEN INCREASING OVER OUR FORECAST
AREA THIS MORNING AS EVIDENCED BY WATER VAPOR SATELLITE IMAGERY AND
ANALYSIS OF HOURLY PWATS FROM THE OPERATIONAL EMC RAP MODEL ONLINE.
DESPITE THE CHANGE IN MOISTURE PROFILES...MODELS SHOW A GOOD BIT
OF CONVECTIVE INHIBITION AT DAYBREAK. WE CANNOT TOTALLY RULE OUT
ISOLATED SHOWERS DEVELOPING ON THE BEACHES OR BARRIER ISLANDS BUT
IT SHOULD SLIP OFFSHORE. NO FOG ISSUES THIS MORNING...TEMPS ARE
WARM IN THE MID TO UPPER 70S WITH A DECENT PRES GRADIENT IN THE
BOUNDARY LAYER.
THE SUBSIDENCE WE HAD AROUND ON SUNDAY HAS DEPARTED OUR REGION THIS
MORNING AND MID LEVEL HEIGHTS ON THE NW PERIPHERY OF THE SUBTROPICAL
RIDGE OVER THE SW ATLC HAVE FLATTENED AND SLIGHTLY WEAKENED. A
SHORT WAVE AND ASSOCIATED MID LEVEL VORT MAX IS FORECAST TO PASS
BY TO THE NORTH TODAY WITH A WEAKER BIT OF VORTICITY ADVECTION
RIPPLING ACROSS S GEORGIA THIS MORNING. WEST FLOW IN THE LOW
LEVELS SHOULD ENSURE ANOTHER HOT DAY IN THE 90S BUT EVENTUAL
CONVECTIVE INITIATION AND DEEPER MOISTURE PROFILES/CLOUD POTENTIAL
COULD KEEP AREAS FROM MAXIMIZING READINGS WARMER THAN THE MID 90S
THIS AFTERNOON. HEAT INDEX VALUES WILL LIKELY TOP OUT IN THE 103
TO 105 DEGREE RANGE THIS AFTERNOON AS CONDITIONS WILL BE MORE HUMID
TODAY WITH ELEVATED SURFACE DEW POINTS.
CONSENSUS OF THE MODELS SUGGEST ISOLATED CONVECTION PERHAPS BREAKING
OUT PRIOR TO MID AFTERNOON ACROSS AREAS WEST OF I-95 AS HINTED BY
ADVECTION OF HIGHER 850 MB THETA-E VALUES FROM SW AND CENTRAL
GEORGIA BY 18Z. SHOWER AND TSTM CONVERAGE OVER SE GEORGIA COULD BE
SCATTERED IN SOME LOCATIONS BY MID AFTERNOON BUT POPS NO HIGHER
THAN 25-30 PERCENT IN THAT AREA.
THE MOST IMPRESSIVE LOCATIONS FOR STRONGER CONVECTION LATER TODAY
AND EARLY THIS EVENING WILL EXTEND ACROSS THE NORTH CAROLINA
SANDHILLS SOUTH TO THE EASTERN SOUTH CAROLINA MIDLANDS AND PEE DEE
REGIONS. GRADUALLY INCREASING DEEP LAYERED WIND FIELDS AND RICH
LOW LEVEL MOISTURE CONVERGENCE FUELED BY A WELL DEFINED SURFACE
TROUGH NOTED IN THIS AREA. STEERING PROGS FOR EAST CENTRAL SOUTH
CAROLINA SHOW ENOUGH OF A VEER FROM THE W TO WNW TO SUGGEST SOME
SIGNIFICANT MULTI-CELL OR LINEAR CONVECTION HAVING A CHANCE TO MAKE
A RUN FOR OUR NW TIER AND THE CHARLESTON TRI-COUNTY LATE IN THE
DAY. IF IT DOES...THERE WOULD BE A POTENTIAL WINDOW FOR ISOLATED
SEVERE WEATHER FROM MAINLY DAMAGING WIND GUSTS. THERE IS A BIT TOO
MUCH TIMING AND SPACIAL DIFFERENCES FROM THE HIGHER RESOLUTION
MODELS AT 00Z TO HOLD OUT SEVERE WEATHER MENTIONS IN OUR
HAZARDOUS WEATHER OUTLOOK...BUT IT MAY NEED TO BE INCLUDED ON THE
MORNING UPDATE AFTER 12Z DATA IS ANALYZED. WE BUMPED POPS TO 40
PERCENT ACROSS AREAS NORTH OF CHARLESTON TO TREND.
CONVECTION SHOULD DIMINISH OR MOVE OFFSHORE OF SOUTH CAROLINA COAST
AFTER MID EVENING WITH PARTLY CLOUDY SKIES ALL AREAS OVERNIGHT
ALONG WITH A LIGHT SW BREEZE. POPS SILENT AFTER MIDNIGHT WITH LOWS
73-77 DEGREES.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
TUESDAY...A POTENT SHORTWAVE WILL PASS THROUGH SC DURING THE EARLY
TO MID AFTERNOON. A JUICY AIRMASS WILL BE IN PLACE WITH PWATS ABOVE
2 INCHES. ALTHOUGH THE TIMING ON THE INCREASING SKY COVER AND PRECIP
COULD AFFECT HIGH TEMPS...STRONG WESTERLY FLOW IN ADVANCE OF THE
VORT MAX SUPPORT HIGH TEMPS REACHING THE MIDDLE 90S MOST AREAS.
CLUSTERS OF SHOWERS AND TSTMS EXPECTED TO DEVELOP UPSTREAM AND
EXPAND INTO THE AREA DURING THE AFTERNOON. ALTHOUGH THE
THERMODYNAMIC PROFILES ARE NOT GOING TO BE TOO TERRIBLY
IMPRESSIVE...GIVEN THE FORCING AND TIME OF YEAR WE CANNOT RULE OUT A
FEW SEVERE STORMS.
THE 500 MB RIDGE WILL GRADUALLY BUILD ACROSS THE AREA WEDNESDAY AND
THURSDAY WITH INCREASING UPPER HEIGHTS AND DEEP WNW FLOW. ASIDE FROM
SOME CIRRUS...SKIES SHOULD BE SUNNY BOTH DAYS WITH LATE AFTERNOON
SEA BREEZE CIRCULATIONS ALONG THE COAST. THICKNESSES SUPPORT HIGH
TEMPS IN THE UPPER 90S BOTH DAYS WITH TEMPS REACHING THE LOWER TO
MIDDLE 90S NEAR THE IMMEDIATE COAST. ON THURSDAY WE COULD EASILY SEE
SOME READINGS AT THE CENTURY MARK ACROSS INLAND GA. FAIRLY WARM MID
LEVELS AND LACK OF APPRECIABLE FORCING WILL ONLY SUPPORT ISOLATED
SHOWERS AND TSTMS BOTH DAYS. THE HEAT INDICES ARE THE MAIN CONCERN.
THE EXACT DEWPOINTS AT THE TIME OF MAX TEMP ARE CRITICAL TO
DETERMINING THE HEAT ADVISORY POTENTIAL. HOWEVER IT IS VERY
DIFFICULT TO PIN DOWN THE DEWPOINTS THIS FAR IN ADVANCE. OUR CURRENT
FORECAST SHOWS HEAT INDICES TOPPING OUT AT 106-109 ON WEDNESDAY AND
105-110 ON THURSDAY. WE CANNOT RULE OUT A HEAT ADVISORY FOR PORTIONS
OF THE AREA EITHER DAY...THOUGH THURSDAY IS LOOKING LIKE THE WORST
OF THE TWO DAYS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE UPPER RIDGE AXIS TO OUR WEST WILL BECOME MORE AMPLIFIED WHILE A
TROUGH CARVES OUT ACROSS THE MID-ATLANTIC REGION. MEDIUM RANGE
GUIDANCE IS IN GOOD AGREEMENT THAT A BACKDOOR COLD FRONT WILL DROP
TOWARD THE AREA ON FRIDAY...PUSHING THROUGH ON SATURDAY.
COMPRESSIONAL HEATING ON FRIDAY AHEAD OF THE FRONT WILL YIELD HIGHS
IN THE MID TO UPPER 90S. SOMEWHAT COOLER CANADIAN HIGH PRESSURE
BUILDS IN FROM THE NORTH SUNDAY INTO MONDAY WITH INCREASING RAIN
CHANCES AS BETTER CONVERGENCE DEVELOPS.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS PREVAIL THROUGH 06Z TUESDAY. ISOLATED TO SCATTERED
CONVECTION IS POSSIBLE AFTER MID AFTERNOON AT BOTH TERMINALS BUT
AT THIS TIME...CONFIDENCE IN TIMING AND COVERAGE IS TOO LOW FOR
INTRODUCTIONS OF VCTS TO THE FORECAST. THE 12Z TAF WILL LIKELY
INTRO SOME VCTS AT KCHS...STILL EVALUATING AT THIS TIME.
EXTENDED AVIATION OUTLOOK...ISOLATED TO SCATTERED AFTERNOON
SHRA/TSRA EXPECTED THROUGH FRIDAY WITH VERY BRIEF FLIGHT
RESTRICTIONS POSSIBLE.
&&
.MARINE...
THE COASTAL WATERS ARE BETWEEN A LOW PRES AREA OVER THE SOUTHERN
MID ATLC REGION AND HIGH PRES LODGED IN TO THE SOUTH. AN ENHANCED
PRES GRADIENT WILL SUPPORT SW FLOW 10 TO 15 KT WITH LATE DAY
ENHANCEMENTS. NOCTURNAL SURGING TONIGHT WILL RESULT IN A MORE
SOLID 15 KT ACROSS NEAR SHORE WATERS WITHIN 10 MILES AND UP
TO 20 KT ONCE AGAIN BEYOND THE PILOT BUOYS...ESPECIALLY FROM
GRAYS REEF SEAWARD. SEAS 2 TO 3 FT ON AVERAGE NEAR SHORE TODAY
AND 3 TO 4 FT TONIGHT. A PERIOD OF 5 FT WAVES ARE POSSIBLE IN
OUTER GEORGIA WATERS.
ATLANTIC HIGH PRESSURE TO THE SOUTHEAST AND AN INLAND TROUGH WILL
MAINTAIN AN ENHANCED SW WIND FLOW TUESDAY AND TUESDAY NIGHT WITH
WIND SPEEDS UPWARDS OF 15-20 KT. A RELAXING GRADIENT WEDNESDAY
THROUGH SATURDAY WILL DROP WINDS TO 15 KT OR LESS. OVER THE WEEKEND
A FRONT WILL DROP THROUGH THE WATERS WITH WINDS SWINGING AROUND TO
NE.
&&
.EQUIPMENT...
THE CHARLESTON SC WSR-88D /KCLX/ REMAINS OUT OF SERVICE DUE TO A
SIGNIFICANT MECHANICAL FAILURE. REPAIR WORK CONTINUES AND THE
RADAR COULD BECOME OPERATIONAL AS EARLY AS AUGUST 20TH OR 21ST.
UNTIL THE CHARLESTON SC RADAR RETURNS TO SERVICE...FOR DOPPLER
RADAR COVERAGE OF SOUTHEAST GEORGIA AND SOUTH COASTAL SOUTH
CAROLINA UTILIZE SURROUNDING RADARS INCLUDING KJAX...KJGX...
KVAX...KCAE AND KLTX.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1257 AM CDT MON AUG 18 2014
.DISCUSSION...
925 PM CDT
AN AREA OF STRATUS ACROSS SOUTHERN LAKE MICHIGAN AND IMMEDIATE
ADJACENT AREAS OF ILLINOIS AND INDIANA MUCH OF TODAY HAS EXPANDED
RAPIDLY SINCE SUNDOWN AND LOOKS TO ENCOMPASS MUCH OF IF NOT THE
ENTIRE FORECAST AREA BY EARLY OVERNIGHT. THIS IS EXPANDING IN
LIGHT NORTHEAST WIND FLOW UNDERNEATH A STRENGTHENING INVERSION.
ALL IN ALL A SETUP THAT SHOULD FAVOR IT TO CONTINUE AND RAP
SOUNDINGS SUPPORT THIS. VISIBILITY HAS TEMPORARILY BEEN UNDER 1SM
AT VALPARAISO AND EARLIER AT MICHIGAN CITY. AREAS OF DENSE FOG
WILL BECOME PROGRESSIVELY MORE LIKELY AS THE NIGHT
PROGRESSES...ESPECIALLY THOSE NOT UNDER THE PRESENT STRATUS. WITH
THE LIGHT WIND REGIME FOG SHOULD BE SLOW TO IMPROVE EARLY MONDAY
MORNING...PROBABLY IMPACTING THE MORNING COMMUTE IN PLACES. WILL
CONTINUE TO MONITOR IF A DENSE FOG ADVISORY WILL BE NEEDED. FOR
NOW HAVE BEEFED UP DENSE WORDING IN THE FORECAST AND HIGHLIGHTED
WITH GRAPHICAL NOWCAST.
MTF/CMS
//PREV DISCUSSION...
301 PM CDT
A WARMER...MORE HUMID...AND POTENTIALLY MORE UNSETTLED PATTERN IS ON
THE WAY FOR MUCH OF THE UPCOMING WEEK. MOISTURE CHANNEL IMAGERY
SHOWS THE UPPER LOW WHICH PROVIDED SOME SHOWER ACTIVITY YESTERDAY
MOVING MORE STEADILY ACROSS THE OHIO VALLEY. TO THE NORTH...A WAVE
IS MEANDERING EASTWARD ACROSS CENTRAL MINNESOTA WHILE A CLOSED UPPER
LOW SPINS OVER SOUTHERN MANITOBA. THIS TROUGH WILL DETERMINE THUNDER
CHANCES MONDAY NIGHT. ALSO OF NOTE IS A SERIES OF UPPER LOWS OVER
THE NORTHERN PACIFIC NEAR ALASKA. ENERGY FROM THESE SYSTEMS WILL
TRANSLATE INTO WESTERN/CENTRAL CANADA AND HELP FORCE UPPER RIDGING
OVER THE U.S. MIDWEST BRINGING THE AFOREMENTIONED WARM UP. AT THE
SURFACE...WEAK LOW PRESSURE IS OVER THE LOWER OHIO VALLEY IN
CONJUNCTION WITH THE UPPER LOW. ANOTHER WEAK LOW IS STRETCHED ACROSS
WESTERN MINNESOTA WHILE HIGH PRESSURE IS CENTERED OVER CENTRAL
ONTARIO. ANOTHER LOW IS OVER SOUTHERN MANITOBA IN CONJUNCTION WITH
THE BETTER ORGANIZED UPPER LOW IN THAT VICINITY.
TONIGHT...THE MAIN CONCERN TONIGHT WILL BE FOG/STRATUS AS RESIDUAL
LOW LEVEL MOISTURE LINGERS IN THE MIDST OF WEAK LOW LEVEL FLOW AND A
WEAK RIDGE AXIS. THE RIDGE AXIS WILL STRETCH ACROSS NORTHWEST AND
NORTH CENTRAL ILLINOIS BY MONDAY MORNING. WESTERN AREAS APPEAR TO BE
FAVORED FOR FOG DEVELOPMENT WHILE EASTERN AREAS MAY SEE MORE IN THE
WAY OF STRATUS...ESPECIALLY IF SOME EXISTING STRATUS IS UNABLE TO
ERODE INTO THE EVENING...ESPECIALLY NEAR THE LAKE. WILL INCLUDE FOG
MENTION IN THE FORECAST FOR MOST AREAS BUT THERE IS DECENT POTENTIAL
FOR DENSE FOG SO WILL NEED TO MONITOR THIS. WESTERN AREAS LOOK TO
HAVE THE BEST CHANCE FOR THIS AS THEY MAY CLEAR OUT THIS EVENING AND
BE IN CLOSEST PROXIMITY TO THE RIDGE AXIS.
MONDAY AND TUESDAY...THE UPPER WAVE OVER MINNESOTA WILL TRACK EAST
WITH ITS EFFECTS LARGELY STAYING TO THE NORTH OF THE AREA INTO
MONDAY MORNING...EXCEPT FOR SOME INCREASED MID AND HIGH LEVEL CLOUD
COVER. HOWEVER THE MANITOBA LOW WILL BE TRACKING EAST-SOUTHEAST
ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI RIVER VALLEY MONDAY
BEFORE SLOWING OVER THE WESTERN GREAT LAKES MONDAY NIGHT. THIS WILL
PUSH ASCENT INTO THE AREA AS EARLY AS LATE MONDAY AFTERNOON IN THE
NORTHWEST BUT MORE LIKELY MONDAY EVENING INTO MONDAY NIGHT. A MORE
FOCUSED SURFACE TROUGH AXIS IS FORECAST TO CROSS THE AREA SOME TIME
EARLY TUESDAY BRINGING THE MOST FOCUSED CHANCE FOR SHOWERS AND
THUNDERSTORMS ESPECIALLY ACROSS CENTRAL AND NORTHERN AREAS. LATEST
FORECAST GUIDANCE SHOWS QUITE A BIT OF SPREAD IN TERMS OF TIMING OF
THE BEST FOCUS FOR PRECIP. WILL CARRY HIGHEST POPS MONDAY EVENING
AND OVERNIGHT WITH LOWER POPS LATER TUESDAY AS FOCUS IS LOST BUT
UPPER CYCLONIC FLOW CONTINUES AROUND THE STALLED UPPER LOW TO THE
NORTH FOR THE MORNING. SOME MODEST WARMING WILL OCCUR ALOFT MONDAY
BUT PERIODIC BOUTS OF MID CLOUD MAY HELP LIMIT TEMPS SOMEWHAT...NOT
TO MENTION IMPACT OF ANY MORNING STRATUS/FOG. FLOW WILL CONTINUE OFF
THE LAKE KEEPING LAKESHORE AREAS COOLEST. WILL CARRY HIGHS IN THE
LOW TO MID 70S LAKESIDE AND AROUND 80 INLAND MONDAY WITH SOUTH TO
SOUTHWEST WINDS TUESDAY ALLOWING TEMPS TO REACH THE LOWER 80S FOR
MOST PLACES UNLESS PRECIP TIMING SLOWS AND LINGERS THROUGH MORE OF
THE DAY.
WEDNESDAY INTO THE WEEKEND...A LARGER UPPER TROUGH WILL AMPLIFY OVER
WESTERN CANADA INTO WEDNESDAY AS ANOTHER UPPER LOW DROPS SOUTHWARD
DOWN THE CALIFORNIA COAST AND CUTS OFF. THIS WILL LEAD TO
AMPLIFICATION OF AN UPPER RIDGE ACROSS THE HIGH PLAINS TUESDAY WHICH
WILL QUICKLY SHIFT EAST INTO THE CENTRAL U.S. WEDNESDAY. THIS WILL
BRING A PUSH OF WARM ADVECTION ACROSS THE AREA WEDNESDAY WHICH MAY
BE ENOUGH TO KICK OFF SOME SHOWERS AND STORMS. WITH THE COMPLEX
TROUGH PATTERN TO THE WEST THERE WILL BE THE TENDENCY FOR SHORTWAVES
TO TRAVERSE THE RIDGE WITH SOME POTENTIAL FOR THIS TO BEGIN
WEDNESDAY BUT IT APPEARS MORE LIKELY TO BEGIN WEDNESDAY NIGHT. THE
RIDGE WILL PARK ITSELF OVER THE MIDWEST/WESTERN LAKES INTO FRIDAY
KEEPING THE LIKELIHOOD OF SHORTWAVES TRACKING THROUGH THE FLOW RATHER
HIGH. THE TRACK OF THESE WILL DEPEND ON HOW AMPLIFIED THE RIDGE
BECOMES BUT LATEST GUIDANCE CONTINUES TO KEEP THE LOCAL AREA IN A
FAVORED ZONE FOR THESE WAVES. THE AIRMASS WILL BECOME VERY MOIST BY
THURSDAY WITH PRECIPITABLE WATER VALUES PUSHING/TOPPING 2 INCHES.
BETWEEN THE POTENTIAL WAVES AND THE VERY MOIST AIRMASS SEVERAL
ROUNDS OF THUNDERSTORMS MAY AFFECT THE FORECAST AREA FROM LATER
WEDNESDAY THROUGH FRIDAY. IF THE AIRMASS BECOMES AS MOIST AS
EXPECTED THEN ANY STORM WILL HAVE A GOOD CHANCE TO BRING HEAVY
RAINFALL. RAINFALL POTENTIAL WILL NEED TO BE WATCHED CLOSELY OVER
THE NEXT SEVERAL DAYS ESPECIALLY IF MULTIPLE ROUNDS LOOK MORE
LIKELY. THIS RIDGE LOOKS TO AMPLIFY NORTHWARD SATURDAY PUSHING THE
FAVORED STORM TRACK TO THE NORTH. EVOLUTION BEYOND SATURDAY IS MORE
UNCERTAIN AND WILL BE DRIVEN BY THE MOVEMENT OF THE LARGE UPPER
TROUGH OVER NORTHERN U.S. AND CANADIAN ROCKIES. GUIDANCE IS IN
DISAGREEMENT ON HOW QUICKLY THIS OCCURS. OTHERWISE...HIGHS WILL WARM
FROM MIDWEEK INTO THE WEEKEND AS WILL HUMIDITY LEVELS. THE WILD CARD
WILL BE THUNDERSTORMS WITH THEIR TIMING AND LINGERING EFFECTS SUCH
AS CLOUD COVER PLAYING A KEY ROLE IN HOW WARM THINGS GET. MINIMAL
THUNDER IMPACT WOULD RESULT IN HIGHS IN THE MID AN UPPER 80S BY
THURSDAY WITH 90 POSSIBLE...ESPECIALLY IF THE RIDGE AMPLIFIES MORE
THAN CURRENTLY THOUGHT.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* IFR CIGS INTO MONDAY MORNING...OCNL LIFR POSSIBLE.
* NORTHEAST WINDS BECOMING LGT/VRBL OVERNIGHT AND THROUGH LATE
MONDAY MORNING.
* SSWLY WINDS TURNING EAST WITH THE PASSAGE OF A LAKE BREEZE.
SPEEDS APPROACHING 10 KT LATE MONDAY AFTERNOON.
* SHRA LIKELY LATE MONDAY EVENING AND CHANCE TSRA LATE MONDAY
NIGHT.
KREIN
//DISCUSSION...UPDATED 06Z...
AN AREA OF LOW STRATUS HAS SPREAD ACROSS NERN IL/NWRN IN WITH
PREVAILING IFR/LIFR CIGS. AT ISSUANCE TIME...THE ONLY TAF SITE NOT
UNDER THE STRATUS DECK WAS RFD...WHICH REMAINED UNDER MOSTLY CLEAR
SKIES. LATEST SATELLITE IMAGERY SHOWS THAT THE LEADING EDGE OF THE
STRATUS IS STEADILY MOVING WEST AND ANTICIPATE THAT IT SHOULD
OVERSPREAD RFD BTWN 07-08Z. CIGS THERE SHOULD QUICKLY DROP TO IFR
LEVELS AS WELL. WITH A GREATER PERIOD OF CLEAR SKIES AND LIGHTER
WINDS...RFD ALSO HAS THE POTENTIAL FOR VSBY TO DROP INTO IFR
RANGES AS WELL. THE CHICAGO AREA TAF SITES ARE LESS LIKELY TO SEE
SUCH VISBY RESTRICTIONS AS THE AREA HAS BEEN UNDER PERSISTENT
STRATUS COVER AND HAS SEEN SLOWER COOLING TONIGHT AS WELL AS WIND
SPEEDS REMAINING HIGHER...GENERALLY ARND 6-8KT OVERNIGHT.
FOR THE DAYTIME HOURS TOMORROW...THERE WILL BE 2 CONCERNS...THE
TIMING OF CIGS IMPROVING AND THE TIMING OF A LAKE BREEZE BOUNDARY
PUSHING INLAND. AS FOR THE CIGS...ANTICIPATE THAT DAYTIME
INSOLATION SHOULD ALLOW FOR CIGS TO BURN OFF AND IMPROVE TO VFR BY
EARLY AFTERNOON. WITH A VERY WEAK PRESSURE GRADIENT IN
PLACE...WINDS SHOULD BE LGT/VRBL THROUGH LATE MORNING...BECOMING
SSWLY UP TO 8KT FROM LATE MORNING THROUGH EARLY AFTERNOON. THE
COMBINATION OF A WEAK GRADIENT AND DIFFERENTIAL HEATING BETWEEN
LAND...FOLLOWING THE STRATUS BURN OFF...AND THE WATER...A LAKE
BREEZE SHOULD DEVELOP. THE LATEST HIGH RES MODEL GUIDANCE SUGGESTS
THAT THE LAKE BREEZE SHOULD PUSH THROUGH ORD/MDW BY ARND 21-22Z.
THE NEXT CONCERN WILL BE TIMING OF PCPN MOVING INTO THE AREA
ASSOCIATED WITH A STRONG MID LEVEL SHORTWAVE. THE LATEST MODEL
GUIDANCE SUGGESTS THAT SOME SHOWERS COULD MOVE INTO THE RFD AREA
AS EARLY AS THE LATE AFTERNOON OR EARLY EVENING HOURS WITH THE
BETTER CHANGES FOR THUNDER DURG THE LATE EVENING HOURS AND THEN
SPREADING TO THE CHICAGO AREA TERMINALS BY AROUND MIDNIGHT. THIS
SHOULD BE A SLOW MOVING FEATURE AND IS EXPECTED TO STRENGTHEN
THROUGH THE NIGHT...SO THE PERIOD OF SHRA/TSRA COULD POSSIBLE LAST
THROUGH THE EARLY MORNING HOURS.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN IFR CIGS THROUGH DAYBREAK...LOWER THAT CIGS COULD LOWER
TO LIFR LEVELS.
* MEDIUM IN WIND SPEED MONDAY AND TIMING OF THE WIND SHIFT TO ELY
FOLLOWING THE PASSAGE OF THE LAKE BREEZE.
* MEDIUM TO HIGH FOR A PERIOD OF SHRA/TSRA MONDAY NIGHT...BUT LOW
IN THE TIMING OF IMPACT AT THE TERMINALS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...TSRA LIKELY...ESPECIALLY DURING THE MORNING.
WEDNESDAY-SATURDAY...PERIODIC CHANCES OF TSRA.
MTF
&&
.MARINE...
150 PM CDT
A COLD FRONT HAS CLEARED THE SOUTHERN TIP OF THE LAKE...AND NORTH TO
NORTHEAST WINDS HAVE OVERSPREAD LAKE MICHIGAN WITH HIGH
PRESSURE OVER SOUTHERN ONTARIO AND LOW PRESSURE IN FAR SOUTHERN
ILLINOIS. EXPECT WAVES TO BUILD GENERALLY INTO THE 2 TO 4 FT
RANGE OVER THE SOUTHERN HALF OF THE LAKE BEFORE EASING SOME LATE
TONIGHT. BOTH THE CANADIAN HIGH AND THE LOW IN SOUTHERN ILLINOIS
WILL WORK THEIR WAY EASTWARD TONIGHT INTO MONDAY WHICH WILL
SLACKEN THE WINDS AND VEER THEM TO MORE OF AN EASTERLY DIRECTION
TONIGHT THAN SOUTH TO SOUTHEASTERLY ON MONDAY. ANOTHER WEAK LOW
PASSING THROUGH THE CANADIAN PRAIRIES WILL WORK ITS WAY SE TOWARD
THE NORTHERN HALF OF THE LAKE ON TUESDAY AND SLOWLY DRIFT EAST ON
WEDNESDAY. AFTER A PERIOD OF HIGH PRESSURE...A SERIES OF WEAK LOWS
WILL MIGRATE EASTWARD OUT OF THE PLAINS TOWARD THE LAKE FOR THE
LATTER HALF OF THE WEEK. KMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014 UNTIL 4 AM MONDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002 UNTIL 4 AM MONDAY.
LM...NONE.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1158 PM CDT Sun Aug 17 2014
.UPDATE...
ISSUED AT 902 PM CDT SUN AUG 17 2014
Only a few remaining showers in SE Illinois this evening as lift
associated with the recent storm system diminishes as the low
moves off to the east. The air mass left behind in central/SE
Illinois remains quite moist at the surface with dewpoints in the
upper 60s to around 70 and near saturated conditions up to around
750 mb. Skies clearing above will allow for good radiational
cooling which will bring temperatures rapidly down to the
dewpoint. Fog will become prevalent overnight as a result.
Forecasts reflect this well, and will be keeping an eye on the
potential for dense fog formation. The mitigating factors are the
steady light northeast winds which will keep the surface layer
mixed, and the depth of the fog layer may preclude dense fog
formation later in the night. So far, updates have been sent to
account for trends on shower activity, temperature, humidity, and
winds and later updates may be sent as fog trends become more
definite.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 259 PM CDT SUN AUG 17 2014
Surface low has dropped into far southern Illinois early this
afternoon with remnant MCV still evident on radar imagery over the
far southeast CWA. This is where most of the lingering showers are
continuing, with a few as far north as Taylorville and Tuscola. Some
thinning of the low clouds has been developing but skies still
mainly cloudy.
Main concern for this part of the forecast is with fog potential
tonight. Cloudiness across far northern Illinois and southeast Iowa
is more cellular in nature and should diminish with loss of daytime
heating. Latest RAP guidance showing the northern CWA becoming
partly cloudy this evening. With northeast flow continuing, not a
lot of drying will take place in the lower levels with dew points
upstream still in the mid 60s in many areas. This should allow
visibilities to start dropping by late evening across the north.
Model guidance showing a fair range as to how extensive or thick the
fog gets, so for now will only mention patchy or areas of fog in the
grids for late tonight and early Monday. Skies expected to become
partly to mostly sunny by midday as forecast soundings are rather
dry.
In terms of the lingering showers, most of what`s left in our area
is along a weak trough axis dropping into southern Illinois, aided
by the upper low which is currently located in far southwest
Indiana. Am expecting the showers to fade early this evening as the
low pulls away. On Monday, have maintained some isolated showers/
storms across the eastern CWA during the afternoon as a weak wave
passes through the area.
&&
.LONG TERM...(Monday night through Sunday)
ISSUED AT 259 PM CDT SUN AUG 17 2014
Monday night will feature an upper trough and weak surface low
tracking from the upper midwest into the western Great Lakes, with a
cold front extending south into northern Illinois. Rain chances will
return to areas NW of the I-55 later Monday evening, with chances
expanding to Indiana along and north of I-72 by 12z/7am Tuesday.
Better forcing from the 500mb vort max should remain in northern IL,
but moisture convergence along the front and a weak 300mb jet max
overhead could provide just enough lift for a few storms with the
front. No severe weather is expected, especially with limited
instability overnight.
Tuesday should see a decreasing trend in rain/storm chances in the
afternoon as the bulk of the mid and upper level energy departs to
the east. The break in the rain should continue Tues night for all
but the far southwest KILX CWA, from Jacksonville to Effingham,
where a warm front will quickly approach the area. Rain/storm
chances will remain mainly southwest of Havana to Lincoln to
Shelbyville on Wednesday as the front slowly pushes into IL.
That warm front is expected to usher in a progressively warmer
airmass the remainder of the week and into the weekend. Wednesday
night, an MCV is projected to move from N Iowa across N Illinois,
with enough support from strong mid level warm air advection and a
low level jet across central IL to trigger showers/storms across most
of our forecast area.
Low surface pressure and a stalled frontal boundary are still
expected across northern Illinois for Thursday, keeping rain chances
going into Thursday night. The front is expected wash out Thursday
night as warming continues through a deep layer of the atmosphere.
The warming at mid levels will eventually work to cap the atmosphere
and limit storm potential, despite ample low level moisture. A
shortwave is forecast by the ECMWF to move from Nebraska across N
Illinois Saturday, which could affect our northern counties with a
few storms, depending on the extent of elevated CAPE above the
capping inversion.
The ECMWF is also showing a cold frontal passage following the
shortwave on Saturday night, bringing a period of storms and
slightly cooler air for Sunday. The GFS keeps the upper level ridge
entrenched over IL, limiting much storm potential by keeping
shortwave tracks north of central IL. It also has much warmer
conditions continuing into Sunday. Confidence remains low on the
scenario for next weekend due to the differences.
Heat and humidity levels will climb the last half of the week, as
highs reach into the lower 90s south of Lincoln to Mattoon Thurs
through Saturday. Dewpoints in the low to mid 70s will help push
heat index readings into the upper 90s to around 100 in at least the
south half of the KILX CWA.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1158 PM CDT SUN AUG 17 2014
MVFR vsby has become predominant with local IFR/LIFR
cigs/vsby over central and SE Illinois as fog begins to develop
this evening. Overnight, fog will develop, with potential for
LIFR or VLIFR conditions...mainly 07Z-15Z. So far, steady light NE
winds 5-10 kts has kept fog diffuse through mixing of the surface
layer, but winds should decrease overnight as pressure gradients
relax across the region. Improving conditions after 15Z with
ceilings becoming sct-bkn030 for most of the afternoon. A weak
trough and surface low moving in from the NW Monday evening will
bring a chance of rain back to areas KPIA-KBMI northward after
00Z, but chances for significant vsby/cig reduction in precipitation
remain too low for mention in central IL TAFs at this time.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ONTON
SHORT TERM...GEELHART
LONG TERM...SHIMON
AVIATION...ONTON
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1240 AM CDT Mon Aug 18 2014
.UPDATE...
Issued at 812 PM CDT SUN AUG 17 2014
Monitoring two MCS complexes tracking southeast over southern
Nebraska and north central Kansas. The Nebraska cluster maintains
a strong outflow boundary around 50 MPH gusting out ahead of the
main line showing a history of 60 to 70 mph winds. Thunderstorm
cluster in Kansas has recently reported wind gusts near 60 mph.
Environment ahead of the system is characterized currently by 3500
J/KG of MLCAPE and effective shear increasing to near 30 KTS as a
southwesterly LLJ ramps up over north central Kansas. Current thinking
is similar to latest runs of the HRRR depicting the two clusters
converging as they track south and east over the CWA. Have therefore
increased precip chances over north central Kansas. Instability gradient
weakens towards central and eastern portions of northeast Kansas
and would expect the cluster to weaken in severity between
midnight and 7 AM. Between now and midnight, slight risk of severe
weather was expanded across north central areas where wind gusts
between 50 and 60 mph and small hail are possible.
&&
...Update to aviation forecast discussion...
.SHORT TERM...(This Evening through Monday)
Issued at 343 PM CDT SUN AUG 17 2014
Water vapor imagery showing next shortwave trough and associated
frontal boundary moving thru northwest NE. Thunderstorms have
developed over north central NE and should propagate southeastward
within moisture axis situated across central NE into far northern
KS that will lift slowly northward through the night. Expect NE
convection to weaken later this evening with the loss of heating and
weaker shear further south towards the KS border. Will still however
keep the high chance pops near the NE border and decrease southward
in weaker warm air advection. The most likely period will be near
the state line towards sunrise in the far northeast corner. Lows
tonight will be in the middle to upper 60s. More mixing and
increasing clouds should limit fog potential tonight.
Front to the north will move southeast and bisect the cwa northeast
to southwest by mid to late afternoon. Axis of higher cape will set
up along and ahead of the front. Although the shear along the front
will not be as strong as further north and a capping inversion will
be in place...expect afternoon heating and weak convergence along
the front to allow at least some isolated thunderstorms to develop.
If they do...a deeply mixed atmosphere with temps well into the
middle and upper 90s would favor potential strong wind gusts with
any convection that forms. Will keep highest chance pops along and
ahead of the front...or primarily just north and west of the
Turnpike.
.LONG TERM...(Monday Night through Sunday)
Issued at 343 PM CDT SUN AUG 17 2014
Expect scattered convection Monday evening as the frontal along the
frontal boundary as it slowly moves southeast. NAM showing MUCAPE
around 5000 J/KG with around 35 to 40kts of bulk shear into the
early evening hours. Could see a few strong to severe storms with
strong wind gusts the main hazard. The front should sag south of the
CWA Tuesday morning before moving northward as a warm front Tuesday
afternoon and Tuesday night. Isentropic lift over the warm front
should generate elevated thunderstorms mainly across the northern
CWA. Areas near Highway 36 will have a small chance of morning
thunderstorms on Wednesday.
Wednesday night through Saturday will see ridge building over the
Southern and Central Plains. Periodic waves will move through the
flow and models differ on timing and resultant precipitation
placement. Will continue with low end chances of precipitation,
mainly nocturnal. GFS and ECMWF diverge with the timing of an upper
level trough with the GFS keeping the upper trough over the western
states while the ECMWF is much further east over the central U.S..
Will go dry on Sunday given the large differences for now.
Temperatures will be above normal through much of the period.
&&
.AVIATION...(For the 06Z TAFs through 06Z Monday Night)
Issued at 1233 AM CDT MON AUG 18 2014
Remnant cluster of TSRA gradually dissipating over KMHK while gust
front is progged to reach KTOP/KFOE just before 06Z. Gusty winds
prevail through at least 09Z before becoming light and variable.
Models having difficulty handling cloud cover and TSRA with the
HRRR showing some confidence in cluster diminishing south of
KTOP/KFOE. Mentioned VCTS after 07Z in case scattered convection
reforms near terminals. BKN mid level deck lingers through mid
morning before mixing increases south winds during afternoon.
Another round of TSRA possible towards 00Z, however timing and
location still uncertain for mention.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Bowen
SHORT TERM...63
LONG TERM...53
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1105 PM MDT SUN AUG 17 2014
.SHORT TERM...(THIS AFTERNOON THROUGH MONDAY)
ISSUED AT 121 PM MDT SUN AUG 17 2014
EARLY AFTERNOON WV IMAGERY AND RAP ANALYSIS CONTINUE TO SHOW
PERSISTENT RIDGE IN PLACE ACROSS THE SW US. A SHORTWAVE TROUGH IS
EVIDENT OVER NORTHERN COLORADO...WITH H7 TROUGH ON LATEST RAP JUST
OVER THE CENTRAL ROCKIES. RADAR AND VIS SATELLITE SHOW ISOLATED TO
WIDELY SCATTERED THUNDERSTORMS ALREADY DEVELOPING ALONG SURFACE
TROUGH AXIS AHEAD OF UPPER TROUGH OVER OUR SW CWA.
HRRR HAS A REASONABLE HANDLE ON CURRENT COVERAGE AND INDICATED
ACTIVITY MAINLY REMAINING ALONG AND EAST OF A TRIBUNE TO FLAGLER
LINE. MODERATE INSTABILITY IS IN PLACE WITH ML CAPE IN THE 1500-
3000 J/KG RANGE. CIN IS STILL HIGH ACROSS THE EASTERN HALF OF THE
CWA...HOWEVER AS SHORTWAVE TROUGH MOVES EAST LATER THIS AFTERNOON
AND EVENING ML CINH SHOULD WEAKEN ALLOWING FOR ACTIVITY TO SPREAD
EASTWARD. COVERAGE IS STILL A QUESTION WITH DRY INVERTED V TYPE
MOISTURE PROFILES...HOWEVER WITH LARGE SCALE FORCING INCREASE AND
GOOD BL MOISTURE IN PLACE WE SHOULD BE ABLE TO SEE SCATTERED
ACTIVITY DEVELOP. THERE IS AT LEAST AN ELEVATED SEVERE THREAT
CONSIDERING THE FAVORABLE CAPE AND EXPECTATION OF EFFECTIVE SHEER
INCREASING LATER THIS AFTERNOON/EVENING AS TROUGH MOVES INTO THE
REGION. PROFILES WOULD ALSO SUPPORT POTENTIAL FOR MICROBURST
POTENTIAL...WHICH IS ALSO SUPPORTED BY DCAPE VALUES AROUND 1800
J/KG. AS SHORTWAVE TROUGH SHIFTS EAST A WEAK FRONTAL PASSAGE WILL
SLIGHTLY COOL TEMPS ALOFT TONIGHT AND PRECIP SHOULD COME TO AN END
ACROSS THE EAST AFTER MIDNIGHT.
MONDAY...WITH ELEVATED FRONT ACROSS THE NORTH...AND WASHED OUT
FRONT/SURFACE BAROCLINIC ZONE IN THE SOUTH THUNDERSTORM
REDEVELOPMENT WILL BE POSSIBLE ACROSS THE CWA MONDAY AFTERNOON.
ANOTHER WEAK VORTICITY MAX WILL ROTATE JUST NORTH OF THE CWA
MONDAY AFTERNOON/EVENING...WHICH COULD ALSO HELP WITH THUNDERSTORM
INITIATION. PRECIP SIGNAL IS STRONGEST ACROSS THE SOUTHERN CWA
THROUGH MONDAY AFTERNOON ALONG BAROCLINIC ZONE AS IS LIFTS
NORTH...WITH BETTER COVERAGE TOWARDS LATE AFTERNOON IN THE SOUTH.
HIGH TEMPS MONDAY SHOULD BE SLIGHTLY COOLER THAN TODAY...THOUGH
THEY WILL REMAIN ABOVE NORMAL WITH MOST LOCATIONS IN THE LOW-MID
90S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 227 PM MDT SUN AUG 17 2014
SHOWER/THUNDERSTORM ACTIVITY SHOULD CONTINUE ACROSS THE REGION
MONDAY EVENING BEFORE COMING TO AN END EARLY TUESDAY MORNING. AT
FIRST...MAIN ACTIVITY SHOULD MOVE IN FROM NORTH CENTRAL COLORADO
UNDER WEST-NORTHWEST FLOW. GFS CONDENSATION PRESSURE DEFICITS AND
WINDS AT 320K INDICATE THAT ADDITIONAL ELEVATED STORM DEVELOPMENT IS
POSSIBLE BY MIDNIGHT AS MAIN SHORTWAVE TROUGH PASSES THROUGH.
DECIDED TO KEEP CHANCE POPS GOING THROUGH MOST OF THE NIGHT BEFORE
WANING EARLY TUESDAY MORNING...BETWEEN 3-6 AM MDT. SOME OF THESE
STORMS COULD BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS AS THE
MAIN THREAT...TRANSITIONING TO PRIMARILY A LARGE HAIL THREAT WITH
THE OVERNIGHT ELEVATED THUNDERSTORM ACTIVITY.
THROUGH THE REST OF THE EXTENDED FORECAST PERIOD...A PERSISTENT
UPPER LEVEL PATTERN IS THE MAIN STORY BEFORE A PACIFIC NORTHWEST
TROUGH BREAKS THE RIDGE DOWN TOWARDS NEXT WEEKEND. FOR EACH DAY...
SHOWERS AND STORMS ARE POSSIBLE AS WEAK UPPER LEVEL DISTURBANCES
PASS OVER THE NORTHERN PERIPHERY OF THE SOUTHWESTERN U.S. RIDGE.
STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE TUESDAY WITH CAPE OF
2000-2500J/KG ALONG AND NORTH OF INTERSTATE 70...850-500 MB LAPSE
RATES AROUND 8 C/KM AND 0-6 KM BULK SHEAR AROUND 30-35 KTS. SOME
DRIER BOUNDARY LAYER AIR MOVES INTO THE REGION FROM THE WEST FOR
WEDNESDAY AND THURSDAY...LIMITING SEVERE CHANCES SOME BY DECREASING
AVAILABLE MOISTURE AND ATMOSPHERIC INSTABILITY.
AS FOR TEMPERATURES...HOT WEATHER IS EXPECTED TO PERSIST UNTIL THE
RIDGE BEGINS TO BREAK DOWN NEXT WEEKEND. DID LOWER MIN TEMPERATURES
A TOUCH BELOW MODEL GUIDANCE BASED ON RECENT TRENDS OBSERVED AND
COOL THUNDERSTORM OUTFLOWS LIKELY EACH EVENING. MODEL GUIDANCE...
ESPECIALLY THE EUROPEAN...SUGGESTS THAT A COLD FRONT PASSAGE IS
POSSIBLE BY THE END OF THE WEEK. MODEL AGREEMENT IS FAIRLY POOR WITH
THE GFS SUGGESTING THE HOT WEATHER WILL REMAIN. THEREFORE...DID NOT
MAKE ANY LARGE CHANGES TO THE EXTENDED FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1047 PM MDT SUN AUG 17 2014
VFR CONDITIONS WILL CONTINUE OVERNIGHT AT KGLD AND KMCK. BOUNDARY
LAYER RH WILL STAY LOW ENOUGH TO LIMIT ANY STRATUS OR FOG IN THE
MCK AND KGLD AREAS LATE TONIGHT/EARLY MONDAY MORNING. THERE WILL
BE ANOTHER CHANCE OF THUNDERSTORMS MONDAY AFTERNOON AND EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...RRH
AVIATION...FS
AREA FORECAST DISCUSSION
NWS JACKSON KY
129 AM EDT MON AUG 18 2014
.UPDATE...
ISSUED AT 125 AM EDT MON AUG 18 2014
CURRENT CONDITIONS ACROSS THE AREA FEATURE SOME SHOWERS ALONG WITH
SOME ISOLATED THUNDERSTORMS MOVING INTO THE AREA IN THE SOUTHWEST AS
WELL AS SOME ISOLATED POP UP SHOWERS OVER THE EAST AND NORTHEAST.
THIS WILL CONTINUE AS THE PARENT LOW AND ASSOCIATED BETTER LIFT ENTER
EASTERN KENTUCKY INTO THE REST OF THE OVERNIGHT AND INTO THE DAWN
HOURS. NO CHANGE TO THE ZFP IS EXPECTED AS CURRENT POP FORECAST LOOKS
TO BE ON TRACK WITH MINOR CHANGES. EVERYTHING ELSE LOOKS TO BE ON
TRACK. THE CONCERN WITH THE FLASH FLOODING STILL LOOKS TO MINOR AND
RATHER LOCALIZED SO WILL CONTINUE HIGHLIGHTING THOSE ISSUES AS HAS THE
DAY SHIFT WITH THE HWO.
UPDATE ISSUED AT 1035 PM EDT SUN AUG 17 2014
UPDATED THE FORECAST TO BETTER REFLECT CURRENTS CONDITIONS AND MODEL
TRENDS. THE ISOLATED ACTIVITY CURRENTLY OVER THE AREA WILL BE
INCREASING AS THE TROUGH APPROACHES FROM THE WEST. SO FAR
PRECIPITATION AMOUNTS OVER CENTRAL KENTUCKY HAVE CONFIRMED THAT A
FLASH FLOOD WATCH IS NOT NEEDED. ALSO THE HRRR AND NEW NAM WOULD ALSO
BE SUPPORTIVE ON NOT ISSUING A FLASH FLOOD WATCH AT THIS TIME. THE
REST OF THE FORECAST IS ON TRACK.
UPDATE ISSUED AT 905 EDT SUN AUG 17 2014
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. SOME ISOLATED TO SCATTERED SHOWERS ARE CURRENTLY MOVING
ACROSS THE AREA WITH THE HEAVIER PRECIPITATION OVER CENTRAL KENTUCKY.
THIS HEAVIER AREA WILL BE MOVING INTO THE AREA AFTER 11 PM TONIGHT.
LOOKING AT THE MODELS AND THE RAINFALL AMOUNTS UPSTREAM...THE CONCERN
FOR LOCALIZED FLOODING IS A LITTLE LOWER THAN EARLIER THINKING. THERE
STILL COULD BE SOME VERY LOCALIZED ISSUES WILL SOME CREEKS...DITCHES
AND LOW WATER CROSSING RUNNING FULL DURING THE OVERNIGHT AND MORNING
HOURS. THE REST OF THE FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 303 PM EDT SUN AUG 17 2014
MAIN HEAVY RAIN THREAT WILL BE FROM THIS EVENING INTO MONDAY
MORNING. WIDESPREAD 1 INCH RAINFALL AMOUNTS ARE FORECAST TONIGHT INTO
MONDAY WITH ISOLATED SPOTS RECEIVING IN EXCESS OF 2 INCHES. BASED ON
CURRENT RADAR TRENDS AND EXPECTED DEVELOPMENT THIS EVENING THE
HEAVIEST RAINS WILL LIKELY FALL JUST SOUTH OF KY OVER TN.
LOW PRESSURE OVER SOUTHWEST INDIANA AT SURFACE AND ALOFT WILL TRACK
SLOWLY EAST ACROSS KY TONIGHT...BUT IS NOT EXPECTED TO MOVE EAST OF
OUR AREA UNTIL BETWEEN 12Z AND 18Z MONDAY. AS THE LOW MOVES EAST THE 8H
JET WILL RAMP UP AND LIFT WILL INCREASE LATER TONIGHT. MODELS ARE IN
GOOD AGREEMENT WITH PWS FORECAST AROUND 2 INCHES. THIS IDEA IS
SUPPORTED BY GOES SOUNDER DATA THAT WAS AVAILABLE PRIOR TO THE
WIDESPREAD CLOUD COVER. AFTER COORDINATION WITH NEIGHBORING FORECAST
OFFICES WILL NOT BE ISSUING A FLASH FLOOD WATCH AT THIS TIME...BUT
THE SITUATION WILL NEED TO BE MONITORED CLOSELY TONIGHT INTO MONDAY
MORNING. CONVECTION WILL BE LESS ORGANIZED AFTER THE LOW MOVES
EAST OF OUR AREA ON MONDAY...BUT A CHANCE OF SHOWERS AND THUNDERSTORMS
WILL LINGER INTO MONDAY NIGHT ESPECIALLY IN THE EAST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 303 PM EDT SUN AUG 17 2014
MEDIUM RANGE MODELS POINT TO A RETURN TO A MORE TYPICAL SUMMER-LIKE
PATTERN FOR THE SOUTHERN AND CENTRAL APPALACHIANS AS A RIDGE OF HIGH
PRESSURE BUILDS EASTWARD FROM THE SOUTHERN PLAINS IN THE SOUTHEAST
CONUS. HERE AT NWS JACKSON...OUR DAILY AVERAGE TEMPERATURE HAS BEEN
NORMAL OR BELOW EVERY DAY SINCE JULY 23RD. THAT TREND WILL LIKELY
END BY MID WEEK AS TEMPERATURES MODERATE TO SLIGHTLY ABOVE NORMAL
LEVELS. DEWPOINTS AROUND 70 WILL MAKE IT FEEL LIKE SUMMER FOR SURE.
DESPITE THE BUILDING RIDGE ALOFT...A QUASI-STATIONARY FRONTAL
BOUNDARY...A WEAKENED FEATURE LEFTOVER FROM THE SHORT TERM
PERIOD...WILL REMAIN IN OUR VICINITY PRETTY MUCH THROUGHOUT THE LONG
TERM PERIOD. THIS FRONT WILL WAFFLE NORTH AND SOUTH BUT LIKELY
REMAIN CLOSE ENOUGH TO BE A FOCUS FOR DAILY SHOWER AND THUNDERSTORM
CHANCES WITH THE WARM AND UNSTABLE AIRMASS IN PLACE. THIS SHOULD BE
TYPICAL SCATTERED ACTIVITY WITH GREATEST COVERAGE DURING THE
AFTERNOON AND EARLY EVENING HOURS...BUT MAY POTENTIALLY BE AUGMENTED
BY ONE OR TWO ORGANIZED THUNDERSTORM COMPLEXES DROPPING DOWN FROM
THE NORTHWEST ON THE NORTHEAST SIDE OF THE BUILDING UPPER RIDGE.
STORM CHANCES DECREASE SLIGHTLY NEXT WEEKEND AS THE UPPER RIDGE
AMPLIFIES A BIT...BUT CANNOT BE TOTALLY REMOVED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 125 AM EDT MON AUG 18 2014
SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE TO ENTER EASTERN
KENTUCKY THROUGH THE EARLY MORNING HOURS. THIS WILL EVENTUALLY BRING
VISIBILITY AND CEILINGS DOWN TO FIELD MINS EVENTUALLY...MAINLY THOUGH
WHERE HEAVIER SHOWERS MOVE OVER A POINT. WILL EXPECT TO KEEP THESE
CONDITIONS THROUGH THE MORNING BEFORE LIFTING THE CEILINGS INTO THE
AFTERNOON AS THE MAIN LIFT AND MOISTURE FINALLY MOVE OFF TO THE EAST.
EXPECT MOST OF THE TAF SITES TO EXPERIENCE BELOW IFR IN 08Z TO 14Z
PERIOD. WINDS WILL MAINLY BE LIGHT THROUGH THE MORNING BUT THEN
PICKING UP OUR OF THE WEST INTO THE AFTERNOON WITH THE PASSAGE OF THE
SURFACE FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...SBH
LONG TERM...ABE
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
443 AM CDT MON AUG 18 2014
.DISCUSSION...
CONVECTION OVER SW AR HAS RAPIDLY DEVELOPED ON THE ERN PERIPHERY
OF AN MCV...WHERE RADAR AND SATELLITE INDICATE TO BE CENTERED NEAR
DEQ AS OF 09Z. LOCALLY HEAVY RAINFALL HAS BEEN EVIDENT PER
REFLECTIVITY IMAGERY...WHERE PERSISTENT TRAINING OF CONVECTION HAS
RESULTED IN WIDESPREAD 2-4 INCH RAINFALL TOTALS...PER DUAL POL
ESTIMATES. THE 00Z WRF HAS AGAIN INITIALIZED WELL THIS
MORNING WITH THE POSITION AND SLOWER MOVEMENT OF THE MCV...WITH THE
GFS CONTINUING TO SUFFER FROM FEEDBACK PROBLEMS AND SHOWS A MUCH
MORE RAPID PROGRESSION OF THE MCV ACROSS SW AR /EXITING THE AREA SHORTLY
AFTER 12Z/. MEANWHILE...THE LATEST HRRR IS OUT TO LUNCH AND DOES
NOT EVEN ACKNOWLEDGE THE CURRENT CONVECTION BUT DOES SUGGEST SCT
DEVELOPMENT LATER THIS MORNING CONTINUING THROUGH THE AFTERNOON
NEAR THE PARENT UPPER SHEAR AXIS OVER EXTREME NRN LA. THE CURRENT
HEAVY RAINFALL AXIS LINES UP WELL WITH A TONGUE OF GREATER SFC
THETA-E AND SBCAPES...WHICH RANGE FROM 1000-1500 J/KG AS OF 09Z.
THIS SHOULD CONTINUE TO FAVOR A SHORT TERM HEAVY RAINFALL THREAT
THIS MORNING OVER SW AR...AS THE MCV DRIFTS SLOWLY E THIS MORNING.
HAVE SEEN SCT CONVECTION DEVELOP FARTHER S ACROSS NRN
CADDO/BOSSIER/WEBSTER PARISHES AS WELL BENEATH THE MCV WHERE
850-700MB THETA-E RIDGING SHOULD RESULT IN CONVECTION EXPANDING E
ALONG/N OF THE I-20 CORRIDOR THROUGH MIDDAY. GIVEN THESE
OBSERVATIONS AND THE FACT THAT PW/S SHOULD RANGE FROM 2-2.25
INCHES...HAVE INCREASED POPS TO LIKELY THIS MORNING AND ADDED
HEAVY RAINFALL WORDING ACROSS MUCH OF SW AR...AND HAVE MAINTAINED
MID TO HIGH CHANCE POPS FARTHER S ACROSS NCNTRL LA AS THE MCV
SHIFTS E TO THE MS RIVER BY MIDDAY...AND ITS ATTENDANT SHEAR AXIS
DRIFTS ESE ACROSS THE AREA. THE AFTERNOON SEABREEZE SHOULD BE LESS
OF A FACTOR THIS AFTERNOON OVER DEEP E TX AS 850MB WINDS REMAIN
WSW BENEATH THE SHEAR AXIS...THUS SLIGHT CHANCE POPS SHOULD
SUFFICE FOR THESE AREAS. MAX TEMPS TODAY WILL AGAIN BE A TOUGH
CALL...BUT HAVE LOWERED TEMPS SLIGHTLY TO NEAR 90S OVER SCNTRL
AR/NCNTRL LA...WITH MID 90S EXPECTED ELSEWHERE AS THE AC CANOPY
BENEATH THE MCV GRADUALLY ERODES AND GIVES WAY TO SUNSHINE THIS
AFTERNOON.
THE WRF DOES SUGGEST A WEAK REFLECTION OF THE SHEAR AXIS REMAINING
IN PLACE ACROSS N LA/DEEP E TX THIS EVENING...AND THUS HAVE
MAINTAINED SLIGHT CHANCE POPS FOR THESE AREAS. AFTERWARDS...FLAT
500MB RIDGING IS EXPECTED TO SHIFT E INTO THE SRN PLAINS TUESDAY
FROM THE SRN ROCKIES...WITH A WEAK SEABREEZE POSSIBLE ACROSS DEEP
E TX/SRN SECTIONS OF NCNTRL LA DURING THE AFTERNOON AND EARLY
EVENING. UPPER RIDGING OVER THE WRN ATLANTIC AND ERN GULF REMAINS
PROGGED TO EXPAND FARTHER WNW WHILE ABSORBING THE 500MB RIDGE
CENTER OVER THE LOWER MS VALLEY WEDNESDAY...BEFORE CENTERING
ITSELF OVER THE MID-SOUTH REGION/LOWER MS VALLEY THURSDAY. STILL
SHOULD SEE A COUPLE MORE DAYS OF WEAK SEABREEZE CONVECTION ACROSS
OUR SRN ZONES WEDNESDAY AND THURSDAY...BEFORE LARGE SCALE
SUBSIDENCE BENEATH THE RIDGE INCREASES AS THE RIDGE CENTER BECOMES
POSITIONED OVER THE REGION.
PERSISTENCE WILL DOMINATE LATE THIS WEEK THROUGH THE REMAINDER OF
THE EXTENDED...WITH MAX TEMPS IN THE MID/UPPER 90S EACH DAY. STILL
CAN/T RULE OUT TRIPLE DIGIT HEAT OCCURRING LATE THIS WEEK THROUGH
EARLY NEXT WEEKEND ESPECIALLY OVER E TX/PORTIONS OF NW LA...WHICH
HAVE BEEN MOSTLY VOID OF WETTING RAINFALL THE LAST FEW WEEKS AND
WILL APPEAR TO MISS MUCH OF THE CONVECTION THIS MORNING. BOTH THE
GFS/ECMWF DO SUGGEST THAT THE RIDGE CENTER MAY SHIFT A TAD FARTHER
E INTO THE SE STATES BY MIDWEEK NEXT WEEK...ALLOWING WEAKNESSES
BENEATH THE RIDGE TO RETROGRADE W AND POSSIBLY ALLOW FOR ISOLATED
CONVECTION OVER THE SRN ZONES AS WE ENTER THE FINAL FEW DAYS OF
AUGUST.
PRELIMS TO FOLLOW BELOW...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 94 75 96 75 96 / 30 10 10 10 10
MLU 90 74 95 74 95 / 50 20 10 10 10
DEQ 93 71 95 72 95 / 30 10 10 0 0
TXK 93 74 95 74 96 / 40 10 10 0 0
ELD 91 73 95 73 96 / 60 10 10 0 0
TYR 95 75 96 75 96 / 30 10 10 10 10
GGG 94 74 96 74 96 / 30 10 10 10 10
LFK 96 76 97 76 96 / 20 20 20 10 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1157 PM CDT SUN AUG 17 2014
.AVIATION...
ONE LONE LIGHT RAIN SHWR LEFT BEHIND OF THE EVENING`S CONVECTION...
AND FCST MODEL DEPICTION OF REDEVELOPMENT TONIGHT HAS THUS FAR NOT
PANNED OUT AT ALL. FOR THIS REASON...HAVE OPTED TO DISCOUNT THIS DESPITE
HAVING SOME MODEL GUIDANCE THAT SUGGESTED HIGH CONFIDENCE OF
PREVAILING TSTMS BY SUNRISE. CANNOT RULE OUT A FEW ISOLD INSTANCES
OF REDEVELOPMENT DURING THE OVERNIGHT HOURS...HOWEVER.
ADDITIONALLY...MVFR STRATUS DEVELOPMENT IS EXPECTED AT MOST
SITES AROUND SUNRISE...WHICH WILL LIFT ONCE AGAIN BY AROUND MID
MORNING. ISOLD/SCT CONVECTION IS EXPECTED TO DEVELOP DURING PEAK
HEATING ONCE AGAIN...AND WILL LIKELY DIMINISH SHORTLY AFTER
SUNSET. /12/
&&
.PREV DISCUSSION... /ISSUED 959 PM CDT SUN AUG 17 2014/
DISCUSSION...
DIFFICULT UPDATE THIS EVENING AS WE CONTINUE TO DEAL WITH A WEAK
TO MODERATELY UNSTABLE AIRMASS IN PLACE...A SHORTWAVE NEAR THE
I-30 CORRIDOR OF NE TX/SE OK/SW AR AND INCREASING PRECIPITABLE
WATER VALUES FROM THE WEST ASSOCIATED WITH THE SHORTWAVE.
CONVECTION THUS FAR THIS EVENING HAS BEEN VERY UNEVENTFUL EXCEPT
FOR WIDELY SCATTERED CONVECTION ASSOCIATED WITH A SEA BREEZE
BOUNDARY THAT MOVED A GOOD BIT FURTHER NORTH INTO DEEP EAST TEXAS
AND NORTH CENTRAL LOUISIANA COMPARED TO SATURDAY. AS OF THIS
WRITING...ALL CONVECTION HAS DISSIPATED BUT WE WILL CONTINUE TO
LOOK TO OUR NORTH AND WEST OVERNIGHT FOR THE POSSIBILITY OF
REDEVELOPMENT.
THE ARGUMENTS AGAINST REDEVELOPMENT INCLUDE THE FACT THAT A WEAK
WSW ORIENTED LOW LEVEL JET NEAR 20KTS IS VEERED A LITTLE MORE THAN
I WOULD LIKE TO SEE IT AND THAT WHILE PWATS SHOULD INCREASE
OVERNIGHT SLIGHTLY...MODELS ARE REALLY OVERDOING THE DEPTH OF
MOISTURE IN ASSOCIATION WITH THIS SHORTWAVE/SHEAR AXIS. THE GFS
CONTINUES TO BE USELESS AS IT SUFFERS FROM CONVECTIVE FEEDBACK
PROBLEMS AND THE LATEST HRRR HAS COME IN MUCH DRIER OVERNIGHT THAN
ITS PREVIOUS RUN SUGGESTED. HOWEVER...THE LATEST 00Z NAM SHOWS
QUITE A BIT OF REDEVELOPMENT OVERNIGHT MAINLY NORTH OF THE I-20
CORRIDOR ACROSS EXTREME NE TX/SE OK AND ESPECIALLY SW AR.
THIS LEADS TO A LOW CONFIDENCE FORECAST BUT ALL VARIABLES LEAD ME
TO RAISE POPS SLIGHTLY ACROSS OUR NORTHERN MOST ZONES AND TO TRIM
POPS BACK SLIGHTLY ACROSS THE I-20 CORRIDOR OF NE TX AND NORTHERN
LOUISIANA AS WELL AS POINTS SOUTH.
ONLY MADE SLIGHT CHANGES TO TEMPS OVERNIGHT AS SOME 02Z LOCATIONS
WERE ALREADY NEAR FCST MINS. OTHERWISE...ROUTINE DEWPOINT AND RH
GRIDS WERE ADJUSTED TO MIMIC CURRENT TRENDS...OTHERWISE NO OTHER
SIGNIFICANT CHANGES WERE MADE. /13/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 76 93 75 96 75 / 30 50 20 20 10
MLU 74 90 74 95 74 / 30 50 20 20 10
DEQ 72 94 71 95 72 / 40 20 10 0 10
TXK 75 93 73 95 74 / 40 40 10 10 10
ELD 74 92 73 95 74 / 40 50 20 20 10
TYR 75 94 74 96 75 / 30 40 10 0 10
GGG 75 94 74 96 75 / 30 40 10 10 10
LFK 75 94 75 96 76 / 20 30 20 20 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
230 AM EDT MON AUG 18 2014
.SYNOPSIS...
A TROUGH OF LOW PRESSURE WILL SLIDE OFF THE COAST TONIGHT. A COOL
FRONT WILL DROP SOUTH TOWARDS THE REGION LATE TONIGHT AND MONDAY.
LOW PRESSURE WILL MOVE ALONG THE FRONT FROM THE OHIO VALLEY
TOWARDS THE MID-ATLANTIC REGION LATE TONIGHT THROUGH MONDAY
NIGHT...BEFORE MOVING OFF THE COAST DURING TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
UPDATE OF THE POPS ACROSS THE MD EASTERN TO ACCOUNT FOR A WEAK WAVE
IN THE UPPER LEVELS WHICH IS PRODUCING SOME ISOLD TO SCT SHOWERS.
THE RAP AND HRRR BOTH HAVE A DECENT HANDLE ON THESE SHOWERS WHICH
COULD HOLD ON THROUGH AROUND 06Z. THE SHOWERS SHOULD BE LIMITED IN
OVERALL COVERAGE...BUT WILL TRAIN OVER A FEW LOCATIONS THROUGH
06Z. SHOWER ACTIVITY SHOULD DECREASE AND SHIFT OFF THE COAST
SHORTLY AFTER 06Z.
A TROF OF LO PRES WILL SLIDE OFF THE CST TNGT. SOME WEAK ENERGY
COMBINED WITH MARGINAL INSTABILITY COULD TRIGGER AN ISLTD SHOWER
OR TSTM THIS EVENG. OTHERWISE...GENERALLY PARTLY CLOUDY AND MILD
TNGT WITH LOWS RANGING FM THE MID 60S TO LWR 70S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
WARM AND MORE HUMID MON THRU WED...AS WESTERLY (ZONAL) FLO ALOFT
DOMINATES THE REGION. AN AREA OF DEEPER LO LVL MOIST ASSOCIATED
WITH A MID LVL TROF AND SFC LO PRES WILL AFFECT THE REGION MON
AFTN INTO AT LEAST MIDDAY TUE. THUS...WILL HAVE THE HIGHEST POPS
(30-60%) FOR SHOWERS AND POSSIBLE TSTMS DURING THIS TIME PERIOD.
THE PRESENCE OF AN INCREASINGLY UNSTABLE AIRMASS AND PW VALUES
~1.75-2.00 INCHES WILL ALSO MEAN STRONGER SHOWERS OR TSTMS COULD
CONTAIN HEAVY RAINFALL. POPS DECREASE TO SLGT CHC OR NO CHC (14%)
LATE TUE INTO WED MORNG...DUE TO SUBSIDENCE BEHIND THE DEPARTING
WAVE OF LO PRES. MORE SHRTWV ENERGY IN WEAK UPR AIR TROFINESS WILL
RESULT IN SLGT (20%) TO SML CHC (30%) POPS ACRS THE AREA ON
WED...ESPLY IN THE AFTN/EVENG.
MAX TEMPS WILL MAINLY RANGE FM THE MID 80S TO NEAR 90 THRU THE
PERIOD...WITH MIN TEMPS RANGING FM THE MID 60S TO LWR 70S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BLOCKY PATTERN OVER ERN CANADA AND THE NRN ATLANTIC WILL RESULT IN
AN UNSETTLED WEATHER PATTERN THROUGH THE PERIOD. TEMPS WILL BE NEAR
SEASONABLE...LATE SUMMER NORMS.
SPLIT/BLOCKY FLOW IS TYPICALLY PROBLEMATIC FOR MEDIUM RANGE
GUIDANCE...AND THIS TIME IS NO EXCEPTION. CONTINUE TO TREND FORECAST
TOWARD THE ECMWF AND ENSEMBLE MEANS BASED ON RUN TO RUN CONSISTENCY
AND WPC GUIDANCE...BUT CONFIDENCE IS NOT HIGH ATTM. THIS GUIDANCE
REMAINS BTWN THE MORE AMPLIFIED 17/12Z GFS AND THE NEARLY ZONAL
17/12Z CANADIAN. WITH THAT SAID...FLOW AMPLIFIES OVER THE ERN CONUS
AS MID LEVEL HIGH PRESSURE BUILDS OVER THE GULF STATES.
MEANWHILE...ANOMALOUS HIGH PRESSURE BUILDS OVER ERN CANADA. SRN
STREAM ENERGY OVER THE GREAT LAKES/NE STATES WILL PUSH A SHORTWAVE
INTO THE NE STATES WITH TROUGHING EXTENDING SWD ALONG THE ERN
SEABOARD. QUASI-STATIONARY BOUNDARY WILL SETTLE ACROSS THE
MID-ATLANTIC REGION (ABOUT 100 MILES FARTHER SOUTH THAN 24 HOURS
AGO) DURING THE PERIOD AS FLOW ALOFT REMAINS GENERALLY WLY. THE
FRONT WILL BE THE FOCUS FOR SHOWERS/THUNDERSTORMS THRU THE PERIOD AS
WEAK PERTURBATIONS IN THE FLOW PRODUCE WAVES OF LOW PRESSURE ALONG
THE BOUNDARY. WARM/HUMID AIRMASS WILL BE IN PLACE WITH DEWPOINTS IN
THE UPPER 60S TO LOW 70S AND TYPICAL LATE SUMMER PWATS BTWN 1.5 AND
2 INCHES. HOWEVER...LACK OF CONFIDENCE FACTORS INTO RELATIVELY LOW
CHANCE POPS. CLIMO THIS TIME OF YEAR IS AROUND 20 PCT...BUT WILL GO
HIGHER DURING THE AFTERNOON (30-40%) AND NEAR CLIMO OVERNIGHT DUE TO
MOIST AND MARGINALLY UNSTABLE AIRMASS. IF THE TROUGH PUSHES OFFSHORE
FRI NIGHT-SAT...PERTURBATIONS IN THE NW FLOW COULD BRING ADDITIONAL
CHANCES OF PRECIP TO THE REGION THRU THE WEEKEND...ESPECIALLY IN THE
NE.
WARM THURS AND FRI WITH HIGHS IN THE UPPER 80S TO AROUND
90...COOLING OFF DUE TO CLOUDS/PRECIP THIS WEEKEND. LOW LEVEL
THICKNESSES YIELD TEMPS GENERALLY IN THE MID 80S SAT AND SUN.
OVERNIGHT LOWS GENERALLY IN THE UPPER 60S TO LOWER 70S THRU THE
PERIOD.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL PREVAIL THE REST OF TONIGHT WITH PATCHY FOG
REDUCING VISIBILITIES FROM 3 TO 5SM...INCLUDING TAF SITES KSBY AND
KECG. A COLD FRONT APPROACHES THE REGION FROM THE NORTH AND STALLS
ACROSS THE AREA MONDAY AFTN. THE FRONT COUPLED WITH A WEAK SURFACE
TROUGH WILL INCREASE THUNDERSTORM CHANCES ACROSS THE AREA MON/MON
NIGHT. SE-S WINDS AOB 10 KT MON WILL VEER TO SW-W MON NIGHT. FOR
TUESDAY AND WEDNESDAY...THE FRONT REMAINS STATIONARY ACROSS THE
REGION AND CONTINUES A CHANCE FOR WIDESPREAD SHOWERS/STORMS. THE
LACK OF UPSTREAM FEATURES AND GENERALLY LIGHT STEERING FLOW ALOFT
(LESS THAN 25 KT) COULD LEAD TO MODERATE TO HEAVY RAINFALL IN
SLOW-MOVING STORMS...THUS REDUCING VIS/CIGS UNDER THE STRONGEST
STORM CORES. FOG WILL CONTINUE TO BE A POSSIBILITY OVERNIGHT AND
SHOULD GENERALLY FORM IN AREAS THAT RECEIVE RAINFALL DURING THE
AFTN/EVENING HOURS. DEVELOPING NW FLOW ALOFT WILL KEEP UNSETTLED
CONDITIONS ACROSS THE AREA THURSDAY AND FRIDAY.
&&
.MARINE...
UNSETTLED WEATHER PATTERN WILL PREVAIL OVER THE WATERS THRU THE
FORECAST PERIOD...BUT SCA CONDITIONS ARE NOT ANTICIPATED.
WEAK SFC TROUGH REMAINS OVER THE WATERS THIS AFTERNOON WITH WSW
WINDS AVG 5-10 KT AND WAVES/SEAS 1-2 FT. A COLD FRONT HAS DROPPED
INTO SRN PA LATE THIS AFTERNOON AS AN AREA OF LOW PRESSURE
PROPAGATES EWD OVER THE MID MS/LOWER OH VALLEY. THE FRONT WILL DROP
SWD TONIGHT OVER THE NRN WATERS AS HIGH PRESSURE BUILDS OVER NEW
ENGLAND. FLOW BECOMES NE ON THE BACKSIDE OF THE FRONT WITH WLY FLOW
TO THE SOUTH...REMAINING AOB 10 KT. SFC LOW WILL WEAKEN OVER THE
CNTRL APPALACHIANS AS A SECONDARY LOW DEVELOPS OVER THE WATERS. FLOW
WILL INCREASE SOUTH OF THE WATERS...BUT ANTICIPATE SPEEDS AROUND 10
KT TUES-TUES NIGHT. HIGH PRESSURE SLIDES OVER NEW ENGLAND
TUES...LOCATING OFFSHORE TUES NIGHT WEDS. MEANWHILE...LOW PRESSURE
REMAINS OVER THE WATERS. THE RESULT WILL BE PERIODS OF ONSHORE
FLOW...ESPECIALLY OVER THE NRN WATERS. NE FETCH WILL LIKELY PUSH
SEAS UPWARDS OF 3-4 FT...BUT NOT ANTICIPATING SCA CONDITIONS ATTM.
FRONTAL BOUNDARY REMAINS OVER THE REGION THRU THE WEEK...RESULTING
IN AN UNSETTLED WX PATTERN...BUT SUB-SCA CONDITIONS.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TMG
NEAR TERM...TMG/JAO
SHORT TERM...TMG
LONG TERM...SAM
AVIATION...BMD
MARINE...SAM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
327 AM EDT MON AUG 18 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 332 PM EDT SUN AUG 17 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALF BTWN
A SLOWLY RETREATING...DEEP UPR TROF IN QUEBEC AND AN UPR RDG IN THE
PLAINS/UPR MS RIVER VALLEY. SFC HI PRES UNDER THIS RDG AXIS IS
LOCATED JUST NNW OF LK SUP. THE LLVL NE FLOW ON THE SRN FLANK OF
THIS HI IS FUNNELING SOME COOL...MOIST AIR INTO THE UPR LKS BLO
SHARP SUBSIDENCE INVRN ARND H85 AS SHOWN ON THE LOCAL 12Z RAOBS. THE
RESULT HAS BEEN A GOOD DEAL OF LO CLD COVER. THERE WAS EVEN SOME
DRIZZLE INTO THE EARLY AFTN OVER THE HIER TERRAIN OF THE NCENTRAL...
WHERE THE NE WIND PRESENTS A SHARPER UPSLOPE COMPONENT. BUT WITH
DAYTIME HEATING UNDER THE MID LVL DRY AIR AND SOME DRY H95-9
ADVECTION FM THE NE...THE LO CLDS ARE SHOWING SIGNS OF BREAKING
UP...ESPECIALLY IN AREAS THAT EXPERIENCE DOWNSLOPE FLOW. LOOKING TO
THE W...A VIGOROUS SHRTWV IN SRN SASKATCHEWAN IS MOVING EWD JUST N
OF THE CNDN BORDER AND TENDING TO SUPPRESS THE UPR RDG IN THE
PLAINS. THERE IS ANOTHER WEAKER SHRTWV AHEAD OF THIS FEATURE MOVING
THRU MN. CLDS ALONG WITH SHOWERS/A FEW TS ASSOCIATED WITH THIS
DISTURBANCE/OVERALL H85 THETA E ADVCTN IN THE LARGER SCALE SW FLOW
AHEAD OF THE STRONGER SASKATCHEWAN SHRTWV ARE APRCHG DULUTH EARLY
THIS AFTN.
MAIN FCST CONCERNS INTO THIS EVNG ARE FOCUSED ON LO CLD TRENDS.
TIMING/COVERAGE OF SHOWERS ASSOCIATED WITH PAIR OF UPSTREAM SHRTWVS
ARE THE CONCERNS FOR LATER TNGT AND MON.
LATE TODAY/TNGT...ALTHOUGH THE COMBINATION OF SOME LLVL DRY ADVCTN
AND DAYTIME HEATING MAY BREAK UP THE LO CLDS NOW IMPACTING THE CWA
THRU THIS AFTN...FAIRLY HI INVRN BASE OBSVD ON THE 12Z RAOBS WL
PROBABLY MAINTAIN BKN LO CLDS AT MANY LOCATIONS NOT IMPACTED BY
DOWNSLOPING FLOW AS THE SLOWLY RISING LCL WL REMAIN UNDER THE HIER
INVRN BASE. BUT THE LATEST TRENDS INDICATE THESE CLDS SHOULD BE
ALMOST COMPLETELY GONE BY 00Z. AFTER THIS EVNG...CLD COVER/SCT
SHOWERS NOW APRCHG DLH ARE LIKELY TO SPREAD INTO THE WRN CWA IN
ADVANCE OF LEAD SHRTWV AND WHERE STRONGER H85 THETA E ADVCTN WL
DVLP. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR E WHERE THERE IS
LIKELY TO BE A LONGER PERIOD OF MOCLR SKIES/LGT WINDS CLOSER TO SFC
HI MOVING FM ERN LK SUP INTO ADJOINING ONTARIO. ADDED SOME PATCHY
FOG TO THE FCST IN THIS AREA WHERE TEMPS ARE EXPECTED TO FALL BLO
THE CROSS OVER DEWPTS OBSVD THIS AFTN.
MON...MAIN SHRTWV NOW MOVING THRU SRN SASKATCHEWAN IS FCST TO MOVE
INTO MN DURING THE AFTN. ALTHOUGH SOME SCT SHOWERS ASSOCIATED WITH
THE LEAD DISTURBANCE/AREA OF H85 THETA E ADVCTN MAY SPREAD INTO THE
CENTRAL AND ERN CWA...THESE ARE MORE LIKELY TO WEAKEN WITH TIME AS
THE CLUSTER MOVES TOWARD THE SHRTWV RDG AXIS/DRIER MID LVL AIR ON
THE WRN FLANK OF THE SLOW MOVING QUEBEC TROF. MORE NMRS SHOWERS ARE
LIKELY TO MOVE INTO THE W HALF OF THE CWA IN THE AFTN UPON THE
ARRIVAL OF DEEPER MSTR/MORE VIGOROUS DYANMIC SUPPORT ASSOCIATED WITH
THE MORE VIGOROUS TRAILING SHRTWV IN THE PRESENCE OF DAYTIME
HEATING. WITH FCST MUCAPES NO HIER THAN 100-200 J/KG ASSOCIATED WITH
A GOOD DEAL OF CLD COVER/EXPECTED DAYTIME HI TEMPS MAINLY IN THE
60S...WL LEAVE OUT A MENTION OF TS EXCEPT OVER THE FAR W...WHERE THE
MORE UNSTABLE GFS HINTS MUCAPES MAY REACH 500 J/KG CLOSER TO THE
INCOMING DISTURBANCE/COLDER AIR ALF.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 326 AM EDT MON AUG 18 2014
THE START OF THE PERIOD WILL BE A WET ONE AS AN UPPER WAVE OVER WRN
LAKE SUPERIOR AT 12Z TUE CLOSES OFF AS IT MOVES INTO THE WRN U.P. BY
18Z TUE. THE UPPER LOW WILL THEN SLOW DOWN...FINALLY LEAVING THE
AREA LATER ON WED. THE SFC LOW WILL BE SOMEWHERE OVER NRN WI OR
ALONG THE WI/MI BORDER AT 12Z TUE AND WILL SLOWLY SHIFT E INTO TUE
NIGHT BEFORE MORE QUICKLY MOVING SE ON WED. PWATS ON TUE WILL BE
BETWEEN 1.5 AND 1.7 INCHES /NORMAL IS AROUND AN INCH/...WHICH WHEN
COMBINED WITH THE FORCING FROM THE UPPER LOW/CYCLONIC FLOW AND
UPSLOPE FLOW OFF THE GREAT LAKES IN SPOTS /ESPECIALLY OVER WRN UPPER
MI/...WILL RESULT IN DECENT PRECIPITATION PRODUCTION. THINK THAT
SOME SPOTS COULD SEE EASILY OVER AN INCH OF PRECIP ON TUE/EARLY TUE
NIGHT...DEPENDING ON SMALLER SCALE FEATURES THAT ARE NOT ENTIRELY
CLEAR AT THIS POINT. WHILE IT IS HARD TO GET TOO SPECIFIC ON
HEAVIEST PRECIP PLACEMENT/TIMING...THINK THAT MOST OF THE CWA WILL
SEE PERIODS OF RAIN TUE INTO TUE NIGHT...SO WILL INCREASE POPS TO
LIKELY IN MOST PLACES. WILL LEAVE THUNDER CHANCES TO A MINIMUM...BUT
WILL HAVE A CHANCE OF THUNDER OVER SCENTRAL AND WRN UPPER MI WHERE
CAPES WILL BE A BIT HIGHER AT AROUND 200J/KG DURING THE DAY TUE.
WITH THICK CLOUD COVER...MAX TEMPS ON TUE WILL BE IN THE MID 60S TO
LOW 70S...OR 5 TO POSSIBLY 10 DEGREES BELOW NORMAL.
WED WILL SEE DECREASING PRECIP CHANCES AS THE SYSTEM MOVES SE...BUT
DO LINGER CHANCE POPS THROUGH THE MORNING. BEHIND THE SYSTEM...AN
UPPER RIDGE DEVELOPS OVER THE REGION...WHICH WILL KEEP THINGS A BIT
DRIER THAN EARLY IN THE WEEK. MODELS DO POINT TO PRECIPITATION
OCCURRING ALONG A WARM FRONT THAT MOVES THROUGH THU INTO THU
NIGHT...BUT IT IS UNCERTAIN HOW MUCH PRECIP WILL MAKE IT INTO THE
CWA AS THE FRONT MOVES UNDER THE UPPER RIDGE AND INTO THE DRIER AIR.
WILL HAVE CHANCE POPS THU INTO THU NIGHT...AND SOME LINGERING POPS
INTO FRI.
UNCERTAINTY IS GREATER GOING INTO THE WEEKEND AS MODELS SHOW QUITE A
BIT OF VARIABILITY /RUN TO RUN AND MODEL TO MODEL/ WITH THE
STRENGTH/TRACK/TIMING OF A LOW PRESSURE SYSTEM MOVING SOMEWHERE IN
OR NEAR THE REGION. WHILE MODELS DO APPEAR TO AGREE WITH QPF ON
SAT/SAT NIGHT...THEY DO NOT AGREE ON THE REASON FOR THAT QPF...SO
CONFIDENCE IS LOWER THAN IT WOULD SEEM BY JUST LOOKING AT QPF.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 126 AM EDT MON AUG 18 2014
CHALLENGING FCST SHAPING UP OVER THE NEXT 24HRS AS WEAK DISTURBANCES
MOVE INTO THE UPPER GREAT LAKES. WHILE VFR CONDITIONS SHOULD PREVAIL
OVERNIGHT AT KCMX/KSAW...LIGHT UPSLOPE FLOW AT BOTH TERMINALS MAY
LEAD TO LOW MVFR OR IFR CIGS AT TIMES. SCT SHRA SPREADING THRU NE
MN/NW WI SHOULD AFFECT KIWD OVERNIGHT AND KCMX TOWARD DAYBREAK...
BRINGING MVFR CONDITIONS WITH THE POTENTIAL FOR IFR. ALL TERMINALS
SHOULD GENERALLY BE MVFR FOR MUCH OF THE DAY WITH SHRA SCATTERED
AROUND THE AREA. INCREASINGLY MOIST LOW-LEVELS AND LIGHT UPSLOPE
FLOW SHOULD LEAD TO IFR CONDITIONS DEVELOPING THIS EVENING AT
KCMX/KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT SUN AUG 17 2014
EXCEPT FOR A BRIEF PERIOD OVER EASTERN LAKE SUPERIOR LATE MON NIGHT
INTO TUE WHEN WINDS MAY REACH 20-25 KTS UNDER A SHARPER PRES
GRADIENT BETWEEN HI PRES IN QUEBEC AND A LO TRACKING THRU THE UPPER
MIDWEST...EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A
RELATIVELY WEAK PRES GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE
THE CHILLY WATERS OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
127 AM EDT MON AUG 18 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 332 PM EDT SUN AUG 17 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALF BTWN
A SLOWLY RETREATING...DEEP UPR TROF IN QUEBEC AND AN UPR RDG IN THE
PLAINS/UPR MS RIVER VALLEY. SFC HI PRES UNDER THIS RDG AXIS IS
LOCATED JUST NNW OF LK SUP. THE LLVL NE FLOW ON THE SRN FLANK OF
THIS HI IS FUNNELING SOME COOL...MOIST AIR INTO THE UPR LKS BLO
SHARP SUBSIDENCE INVRN ARND H85 AS SHOWN ON THE LOCAL 12Z RAOBS. THE
RESULT HAS BEEN A GOOD DEAL OF LO CLD COVER. THERE WAS EVEN SOME
DRIZZLE INTO THE EARLY AFTN OVER THE HIER TERRAIN OF THE NCENTRAL...
WHERE THE NE WIND PRESENTS A SHARPER UPSLOPE COMPONENT. BUT WITH
DAYTIME HEATING UNDER THE MID LVL DRY AIR AND SOME DRY H95-9
ADVECTION FM THE NE...THE LO CLDS ARE SHOWING SIGNS OF BREAKING
UP...ESPECIALLY IN AREAS THAT EXPERIENCE DOWNSLOPE FLOW. LOOKING TO
THE W...A VIGOROUS SHRTWV IN SRN SASKATCHEWAN IS MOVING EWD JUST N
OF THE CNDN BORDER AND TENDING TO SUPPRESS THE UPR RDG IN THE
PLAINS. THERE IS ANOTHER WEAKER SHRTWV AHEAD OF THIS FEATURE MOVING
THRU MN. CLDS ALONG WITH SHOWERS/A FEW TS ASSOCIATED WITH THIS
DISTURBANCE/OVERALL H85 THETA E ADVCTN IN THE LARGER SCALE SW FLOW
AHEAD OF THE STRONGER SASKATCHEWAN SHRTWV ARE APRCHG DULUTH EARLY
THIS AFTN.
MAIN FCST CONCERNS INTO THIS EVNG ARE FOCUSED ON LO CLD TRENDS.
TIMING/COVERAGE OF SHOWERS ASSOCIATED WITH PAIR OF UPSTREAM SHRTWVS
ARE THE CONCERNS FOR LATER TNGT AND MON.
LATE TODAY/TNGT...ALTHOUGH THE COMBINATION OF SOME LLVL DRY ADVCTN
AND DAYTIME HEATING MAY BREAK UP THE LO CLDS NOW IMPACTING THE CWA
THRU THIS AFTN...FAIRLY HI INVRN BASE OBSVD ON THE 12Z RAOBS WL
PROBABLY MAINTAIN BKN LO CLDS AT MANY LOCATIONS NOT IMPACTED BY
DOWNSLOPING FLOW AS THE SLOWLY RISING LCL WL REMAIN UNDER THE HIER
INVRN BASE. BUT THE LATEST TRENDS INDICATE THESE CLDS SHOULD BE
ALMOST COMPLETELY GONE BY 00Z. AFTER THIS EVNG...CLD COVER/SCT
SHOWERS NOW APRCHG DLH ARE LIKELY TO SPREAD INTO THE WRN CWA IN
ADVANCE OF LEAD SHRTWV AND WHERE STRONGER H85 THETA E ADVCTN WL
DVLP. EXPECT THE LOWEST MIN TEMPS OVER THE INTERIOR E WHERE THERE IS
LIKELY TO BE A LONGER PERIOD OF MOCLR SKIES/LGT WINDS CLOSER TO SFC
HI MOVING FM ERN LK SUP INTO ADJOINING ONTARIO. ADDED SOME PATCHY
FOG TO THE FCST IN THIS AREA WHERE TEMPS ARE EXPECTED TO FALL BLO
THE CROSS OVER DEWPTS OBSVD THIS AFTN.
MON...MAIN SHRTWV NOW MOVING THRU SRN SASKATCHEWAN IS FCST TO MOVE
INTO MN DURING THE AFTN. ALTHOUGH SOME SCT SHOWERS ASSOCIATED WITH
THE LEAD DISTURBANCE/AREA OF H85 THETA E ADVCTN MAY SPREAD INTO THE
CENTRAL AND ERN CWA...THESE ARE MORE LIKELY TO WEAKEN WITH TIME AS
THE CLUSTER MOVES TOWARD THE SHRTWV RDG AXIS/DRIER MID LVL AIR ON
THE WRN FLANK OF THE SLOW MOVING QUEBEC TROF. MORE NMRS SHOWERS ARE
LIKELY TO MOVE INTO THE W HALF OF THE CWA IN THE AFTN UPON THE
ARRIVAL OF DEEPER MSTR/MORE VIGOROUS DYANMIC SUPPORT ASSOCIATED WITH
THE MORE VIGOROUS TRAILING SHRTWV IN THE PRESENCE OF DAYTIME
HEATING. WITH FCST MUCAPES NO HIER THAN 100-200 J/KG ASSOCIATED WITH
A GOOD DEAL OF CLD COVER/EXPECTED DAYTIME HI TEMPS MAINLY IN THE
60S...WL LEAVE OUT A MENTION OF TS EXCEPT OVER THE FAR W...WHERE THE
MORE UNSTABLE GFS HINTS MUCAPES MAY REACH 500 J/KG CLOSER TO THE
INCOMING DISTURBANCE/COLDER AIR ALF.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 332 PM EDT SUN AUG 17 2014
AT 00Z TUESDAY THE NEXT 500MB WAVE WILL BE SET UP ACROSS MN THROUGH
W ONTARIO. MID/LONG TERM MODELS INDICATE THAT THIS FEATURE WILL
DEVELOP INTO A LOW 12-18Z TUESDAY OVER E MN AND THE W HALF OF THE
MQT CWA. AT THAT POINT...LITTLE MOVEMENT WILL BE EXPECTED AT 500MB
UNTIL AFTER DAYBREAK WEDNESDAY...AS THE 500MB SITS AND SPINS ACROSS
UPPER MI AND LAKE SUPERIOR. THE SFC LOW SHOULD TRACK FROM N AND
CENTRAL MN AT 00Z TUESDAY NEAR THE WI/UPPER MI BORDER ON
TUESDAY...BEFORE EXITING ACROSS LAKE MI TUESDAY NIGHT...AND LOWER MI
ON WEDNESDAY. WITH UPPER MI STAYING ON THE N SIDE OF THE SFC LOW
EXPECT A PERIOD OF CLOUDY CONDITIONS...WITH AFTERNOON TEMPS ON
TUESDAY AVERAGING AROUND 5F BELOW THE SEASONAL NORMAL VALUES. THE
BEST CHANCE FOR PRECIP IS DIFFICULT TO PIN DOWN AT THIS POINT...AS
FCST MODELS VARY SIGNIFICANTLY WITH THE SMALLER SCALE FEATURES WITH
THIS DEVELOPING SYSTEM. WILL CONTINUE TO GO RELATIVELY GENERAL WITH
THE POPS AT THIS POINT. WILL KEEP TS POTENTIAL TO A MINIMUM...GIVEN
THE TRACK OF THE SFC LOW MAINLY TO OUR S...AND MU CAPE VALUES OVER
THE FAR W AOB 100J/KG FAR W TUESDAY MORNING. TUESDAY DURING THE DAY
DOESN/T LOOK MUCH MORE IMPRESSIVE...TOPPING OUT ALONG THE WI BORDER
GENERALLY AROUND 200 J/KG OR LESS /RESTRICTED TS MENTION TO CENTRAL
U.P./.
THE 500MB RIDGE WILL BRIEFLY BUILD OVERHEAD LATER WEDNESDAY INTO
EARLY THURSDAY. OUT OF THE WORK WEEK FROM TUESDAY ON...THIS SHOULD
BE THE DRIEST PERIOD. WILL TRY TO SHOW A BIT MORE IN OUR
FCST...DESPITE THE PW VALUES REMAINING 80-140 PERCENT OF NORMAL
/LOWEST E/.
THE CHANCE OF SHOWERS RETURN LATE THURSDAY INTO FRIDAY AS A
SHORTWAVE/TROUGH GLANCES THE AREA. TS MAY RETURN ON FRIDAY. EXPECT
WAA FRIDAY TO PUSH 850MB TEMPS UP TO 15-19C. IF CLOUDS AND PRECIP
CAN STAY TO A MINIMUM...SFC SHOULD SHIFT TO ABOVE NORMAL READINGS.
AS FOR THE OPEN HOUSE AT THE MQT NWS ON SATURDAY 10AM-2PM
EDT...THERE IS ENOUGH DISCREPANCIES AT THIS POINT IN THE FCST MODEL
DATA TO KEEP A GENERAL BLEND OR CONSENSUS GOING. BOTH THE GFS AND
ECMWF SHOW A 500MB LOW TO THE W OF UPPER MI AT 12Z.
HOWEVER...LOCATIONS VARY FROM N MANITOBA TO THE DAKOTAS...WITH A SFC
LOW OR TROUGH EITHER JUST TO OUR W OR OVER W UPPER MI. IF THE 17/00Z
AND 06Z GFS RUNS ARE CORRECT...WINDS NEAR 20KTS WILL BE POSSIBLE.
THE 12Z RUN DID DIMINISH THESE STRONG WINDS...DOWN TO AROUND 10KTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 126 AM EDT MON AUG 18 2014
CHALLENGING FCST SHAPING UP OVER THE NEXT 24HRS AS WEAK DISTURBANCES
MOVE INTO THE UPPER GREAT LAKES. WHILE VFR CONDITIONS SHOULD PREVAIL
OVERNIGHT AT KCMX/KSAW...LIGHT UPSLOPE FLOW AT BOTH TERMINALS MAY
LEAD TO LOW MVFR OR IFR CIGS AT TIMES. SCT SHRA SPREADING THRU NE
MN/NW WI SHOULD AFFECT KIWD OVERNIGHT AND KCMX TOWARD DAYBREAK...
BRINGING MVFR CONDITIONS WITH THE POTENTIAL FOR IFR. ALL TERMINALS
SHOULD GENERALLY BE MVFR FOR MUCH OF THE DAY WITH SHRA SCATTERED
AROUND THE AREA. INCREASINGLY MOIST LOW-LEVELS AND LIGHT UPSLOPE
FLOW SHOULD LEAD TO IFR CONDITIONS DEVELOPING THIS EVENING AT
KCMX/KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 332 PM EDT SUN AUG 17 2014
EXCEPT FOR A BRIEF PERIOD OVER EASTERN LAKE SUPERIOR LATE MON NIGHT
INTO TUE WHEN WINDS MAY REACH 20-25 KTS UNDER A SHARPER PRES
GRADIENT BETWEEN HI PRES IN QUEBEC AND A LO TRACKING THRU THE UPPER
MIDWEST...EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A
RELATIVELY WEAK PRES GRADIENT DOMINATES THE UPPER GREAT LAKES ABOVE
THE CHILLY WATERS OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
417 AM CDT MON AUG 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 415 AM CDT MON AUG 18 2014
TODAY AND TONIGHT...INTERESTING PATTERN OVER THE NEXT 24-30 HOURS
LOOKS MORE LIKE AN OCTOBER-NOVEMBER SCENE RATHER THAN MID-AUGUST. A
SHORTWAVE OPEN TROUGH WITHIN THE PREVAILING WNW-ESE FLOW WILL SLOWLY
TRAVERSE ACRS THE REGION THRU TNGT...DRAGGING A SFC LOW PRES CENTER
WITH IT. NO REAL BONA FIDE FRONTS ARE ASSOCIATED WITH THIS LOW...BUT
THERE ARE SEVERAL SFC TROUGH SPOKES EMANATING FROM THIS SFC LOW AND
IT IS THESE DISTURBANCES WITHIN A HIGHLY MOIST ENVIRONMENT THAT WILL
PRODUCE EFFICIENT RAIN-MAKING STORMS THRU THE NEXT DAY OR SO.
ALREADY SEEING SLOW-MOVING STORMS OVER WRN WI CONTINUE TO SHIFT
E...AND THESE STORMS ARE WITHIN A PWAT ENVIRONMENT OF OVER 1.6
INCHES. THERE IS ALSO ENOUGH MIDLVL INFLOW TO PRODUCE TRAINING OF
STORMS PLUS MUCAPES OF 1000-2000 J/KG. THIS IS COMBINING TO PRODUCE
POCKETS OF HEAVY RAIN OVER W-CENTRAL WI...AND THE THINKING IS THAT A
SIMILAR ENVIRONMENT FOR TDA INTO TNGT WILL ALLOW FOR SIMILAR-TYPE
STORMS TO FORM LATER TDA AND TNGT. TIMING WILL BE TRICKY...BUT HAVE
GONE THE ROUTE OF SHOWING A PERIOD OF DRYNESS THRU THIS MRNG THEN
GRADUALLY INCRG POPS THRU THE DAY TDA INTO TNGT...BEFORE ENDING POPS
FROM W TO E OVERNIGHT INTO TUE MRNG AS THE SEMI-STACKED LOW PRES
SYSTEM SHIFTS INTO THE GREAT LAKES. GIVEN THAT THE SFC LOW DOES
REMAIN TO THE E OF THE PARENT UPR OPEN WAVE...THERE MAY WELL BE
CONTINUED PRECIP GENERATION THRU TNGT SO HAVE KEPT LIKELY POPS GOING
FOR MUCH OF THE CWFA LATE THIS AFTN THRU TNGT...ESP IN ERN PORTIONS.
WITH THE HIGH PWATS...SLOW STORM MOTION AND/OR TRAINING OF STORMS
AND ADDED LIFT...THERE IS STILL THE POTENTIAL FOR HEAVY RAIN AND
FLOODING. THE OTHER CONCERN...AND THIS IS FOR THIS MORNING...IS
DENSE FOG...PARTICULARLY FOR W-CENTRAL MN. HAD ALREADY SEEN A NUMBER
OF W-CENTRAL MN SITES DROP TO 1/4SM AND 1/2SM VSBY WITHIN AN
ENVIRONMENT THAT HAS NEARLY CALM WINDS AND DEWPOINT DEPRESSIONS OF
TWO OR LESS. THOUGH THERE IS A WIND SHIFT COMING IN FROM THE DAKOTAS
WITH ONE OF THE SFC TROUGHS...AM NOT CONVINCED IT WILL ARRIVE IN
ENOUGH OF A FORM TO MITIGATE DENSE FOG DEVELOPMENT SO HAVE OPTED TO
HOIST A DENSE FOG ADVY THRU DAYBREAK. THE MPX ARE AND HOPWRF MODELS
HIGHLIGHT THE REDUCED VSBY NICELY BUT...SURPRISINGLY...THE SREF IS
NOWHERE NEAR AS BULLISH SO HAVE GONE WITH THE SHORT-TERM MODELS.
THERE IS SOME CHANCE THAT THE ADVY MAY NEED TO BE ADJUSTED GIVEN OB
TRENDS BUT WILL MONITOR AND ADJUST AS NEEDED.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 415 AM CDT MON AUG 18 2014
THE SIMPLE TRANSITION FROM NORTHWEST FLOW TO SOUTHWEST FLOW WILL
BRING REPEATED CHANCES FOR SHOWERS AND THUNDERSTORMS THIS WEEK WITH
RAINFALL POTENTIAL FOR 1-2 INCHES FOR MOST LOCATIONS...AND HIGHER
AMOUNTS UNDER THUNDERSTORMS.
AT THE START OF THE PERIOD ON TUESDAY THE UPPER LEVEL WAVE
RESPONSIBLE FOR MONDAYS PRECIP WILL BE DRIFTING EASTWARD ACROSS
WISCONSIN...BUT FORECAST MODELS AGREE ON AN EMBEDDED SHORTWAVE
ROTATING AROUND THE BACKS SIDE ACROSS THE MN/WI BORDER...TO
EXPANDED POPS WESTWARD TUESDAY AFTERNOON. HIGH PRESSURE WILL BUILD
IN TUESDAY NIGHT...BUT BOUNDARY LAYER DEWPOINTS DONT REALLY DRY
OUT. THIS COMBINED WITH LIGHT WINDS AND CLEARING SKIES WILL
SUPPORT FOG DEVELOPMENT BY EARLY WEDNESDAY MORNING...SO WILL
CONTINUE THIS FROM THE PREVIOUS FORECAST.
THE HIGH PRESSURE WILL BE SHORTLIVED AS AN UPPER LEVEL LOW CARVES
OUT A HIGH AMPLITUDE TROUGH ALONG THE WEST COAST. THIS WILL LEAD TO
SOUTHWEST FLOW ACROSS THE CENTRAL CONUS...WITH A SHORTWAVE COMING UP
ACROSS THE DAKOTAS BY WEDNESDAY. THIS WILL SUPPORT SOUTHERLY LOW
LEVEL FLOW...AND H925 MOISTURE TRANSPORT SHOWS A DIRECT CONNECTION
TO THE GULF MOISTURE WEDNESDAY NIGHT. A WARM FRONT IS FORECAST TO BE
DRAWN OUT EAST/WEST ACROSS THE CWA...SO EXPECT AN MCS TO MOVE ACROSS
THE REGION. SPLIT THE 12HR PRECIP GRID INTO TWO 6HR WINDOWS TO SHOW
THE EASTWARD PROGRESSION OF THE MCS WHICH SHOULD MIRROR THE VEERING
LOW LEVEL JET.
MODELS SHOW THIS WARM FRONT LIFTING NORTHWARD...BUT REPEATED ROUNDS
OF CONVECTION MAY KEEP THE BOUNDARY FARTHER SOUTH THAN CURRENTLY
FORECAST. THIS WOULD HAVE A SIGNIFICANT IMPACT ON TEMPERATURES. IF
THE FRONT IS FARTHER NORTH...WILL SEE LESS CLOUD COVER AND HIGHS
CLOSER TO THE 90S. FOR NOW DID NOT STRAY FROM GUIDANCE AND HAVE
HIGHS IN THE LOWER 80S...BUT THE POTENTIAL IS THERE. SEVERE WEATHER
APPEARS POSSIBLE WITH ADEQUATE DEEP LAYER SHEAR AND INSTABILITY
ALONG AND SOUTH OF THE FRONT. HEAVY RAIN IS ALSO A THREAT WITH
TRAINING THUNDERSTORMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1118 PM CDT SUN AUG 17 2014
WIDELY SCATTERED SHOWERS LATE THIS EVENING WILL BE FOLLOWED BY A
MORE ORGANIZED AREA OF ACTIVITY OVERNIGHT. PREFER THE RAP 0.5KM
AGL CONDENSATIONAL PRESSURE DEFICITS AS A GUIDE FOR CIGS IN THE
NEAR-TERM. THINK IFR CIGS/VSBYS WILL PLAGUE SITES INTO MID MORNING
MONDAY. THEN OCCASIONAL SHOWERS/TS ARE EXPECTED AS THE TROUGH
PASSES ACROSS TOMORROW. EAST/SOUTHEAST WINDS AHEAD OF THE WARM
FRONT...THEN SHIFT TO WEST/SOUTHWEST FOR TOMORROW. SPEEDS AROUND
OR BELOW 10 KTS THROUGH THE PERIOD.
KMSP...
CIGS ARE EXPECTED TO DECREASE OVERNIGHT WITH BKN-OVC IFR LEVEL
CIGS PERSISTING INTO MONDAY MORNING. SCATTERED SHRA/TS ARE
EXPECTED ON MONDAY. WIND SPEEDS STAY AOB 10 KTS THROUGH THE
PERIOD BUT SHIFT FROM EAST/SOUTHEAST TO SOUTHWEST ON MONDAY
MORNING.
/OUTLOOK FOR KMSP/
TUE...VFR. CHC MVFR WITH AFTERNOON TSRA. WINDS NW 5-10 KTS.
WED...VFR. WIND VRB AT 5KTS.
THU...VFR. CHC MVFR WITH TSRA. WINDS SSE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CDT THIS MORNING FOR MNZ041>043-
047>050-054>058-064-065-073.
WI...NONE.
&&
$$
SHORT TERM...JPC
LONG TERM...JRB
AVIATION...LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1117 PM CDT SUN AUG 17 2014
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 142 PM CDT SUN AUG 17 2014
TWO ROUNDS OF THUNDERSTORMS EXPECTED OVER THE NEXT 24 HOURS. THE
FIRST IS THIS AFTERNOON AND THE SECOND IS EXPECTED TOMORROW
MORNING IN MN AND AFTERNOON IN WI.
A NEARLY STATIONARY BOUNDARY IS ROUGHLY BISECTING THE FORECAST
AREA THIS AFTERNOON WITH DEWPOINTS IN THE MID TO UPPER 50S IN THE
FAR NORTHERN FORECAST AREA /CENTRAL MN AND NORTHWEST WI/ AND
LOWER 70 DEWPOINTS ACROSS SOUTH. ALONG AND SOUTH OF THE FRONT
THERE IS A PRONOUNCED INSTABILITY GRADIENT WITH SBCAPE VALUES
RANGING FROM 0-3000J/KG OVER THE SPAN OF 40-60 MILES. THE
SIGNIFICANT INCREASE IN SBCAPE WAS AIDED BY A COUPLE HOURS OF
SUNSHINE THIS AFTERNOON AND MOISTURE POOLING NEAR THE FRONT. THE
SHOWERS THIS AFTERNOON ARE STARTING TO UTILIZE THE LARGE CAPE
VALUES AND ARE NOW PRODUCING A FEW LIGHTNING STRIKES. THE 1830Z
LAPS SOUNDING NOW HAS A FREEZING LEVEL OF 15KFT AND PWAT VALUES OF
1.75"...PROVIDING A GREAT ATMOSPHERE FOR WARM RAIN PROCESSES AND
HIGH RAIN RATES FOR RELATIVELY SMALL SHOWERS. WE EXPECT THESE
INTENSE-SMALL SHOWERS TO CONTINUE MOVING EAST ACROSS EASTERN
MN...WITH A SLOW DIMINISHING TREND NEAR SUNSET.
WE INCREASED POPS AND KEPT THE MENTION OF HEAVY RAIN IN THE
FORECAST TOMORROW FROM 09-21Z...WITH THE EXPECTATION OF ANOTHER
COMPLEX OF THUNDERSTORMS EXPECTED TO MOVE OUT OF SOUTH DAKOTA AND
INTO WESTERN MN BEFORE SUNRISE. WE USED A BLEND OF THE 17.12Z GEM-
REG AND NEW AND IMPROVED 17.12Z NAM...WHICH ARE IN VERY GOOD
AGREEMENT WITH ONE ANOTHER. EARLY LOOK AT SOME THE CAM GUIDANCE
FOR TOMORROW IS ALSO TRENDING THIS WAY. THE UPPER LOW WEST OF LAKE
WINNIPEG AND TRAILING TROUGH AND STRONG PV ADVECTION SHOULD BE THE
FOCUS FOR THIS COMPLEX LATE TONIGHT AND TOMORROW. HARD TO IMAGINE THIS
SECOND COMPLEX MISSING THE FORECAST TOMORROW GIVEN HOW CLOSE WE
ARE NOW.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 407 PM CDT SUN AUG 17 2014
THE BACK EDGE OF THE AFOREMENTIONED COMPLEX WILL BE HEADED EAST
ACROSS ERN MN AND WRN WI AT THE BEGINNING OF THE PERIOD...WITH THE
POSSIBILITY OF RESIDUAL SHOWERS CONTINUING THROUGH MUCH OF THE
NIGHT...ESPECIALLY OVER WI. KEPT POPS IN THE CATEGORICAL RANGE
DURING THE EVENING WITH A GRADUAL TAPERING OVERNIGHT AS THE BEST
CHANCES SHIFT EAST. THE TROUGH WILL BECOME MORE NEGATIVELY TILTED
TUESDAY OVER THE WESTERN GREAT LAKES. DIURNAL SHOWER DEVELOPMENT
APPEARS LIKELY WITHIN A SOMEWHAT MOIST CYCLONIC FLOW EXTENDING
WEST INTO MN AND NORTHEASTERN IA.
SKIES WILL CLEAR TUESDAY NIGHT WITH THE SURFACE RIDGE AXIS ALIGNED
OVER THE EASTERN CWA. EXPECTING AREAS OR WIDESPREAD FOG TO DEVELOP
FROM CENTRAL TO SERN MN EASTWARD INTO WI. THERE MAY BE ENOUGH
RETURN FLOW DEVELOPING LATE TO PRECLUDE FOG FROM BECOMING AS
WIDESPREAD ACROSS SRN AND WRN MN.
MID LEVEL RIDGING WILL BUILD NORTHEASTWARD INTO THE MID MISSOURI
VALLEY DURING THE MIDDLE OF THE WEEK. IT WON/T QUITE REACH THE
CWA...SO THIS REGION OF THE COUNTRY IS LIKELY TO REMAIN UNSETTLED
THROUGHOUT MUCH OF THIS WEEK. THE FIRST WAVE TO RIDE NORTH OF THE
RIDGE WILL ARRIVE LATE WEDNESDAY THRU THURSDAY MORNING. INTRODUCED
LIKELY POPS ACROSS SRN MN WEDNESDAY NIGHT WHERE THE BEST JUXTAPOSITION
OF FORCING AND INSTABILITY WILL RESIDE. THE RESULTANT MCS WILL
DEVELOP OVER SODAK WEDNESDAY AFTERNOON AND TRACK EASTWARD INTO WI
BY MIDDAY THURSDAY.
THE RIDGE WILL RETREAT SOME FRIDAY AS A TROUGH BEGIN TO EJECT
EASTWARD FROM THE PACIFIC NORTHWEST. THE SOUTHWEST FLOW WILL SEND
ANOTHER WAVE INTO THE REGION FRIDAY AND SATURDAY WHEN POPS RETURN
INTO THE HIGH CHC RANGE.
BEYOND SATURDAY...MODELS DIVERGE SIGNIFICANTLY FROM EACH OTHER
AND FROM RUN TO RUN. YESTERDAY THEY SHOWED A STOUT HEAT WAVE OVER
THE MID/UPPER MISSISSIPPI VALLEY AND TODAY THEY SHOW A TROUGH WITH
SUB 560DM HEIGHTS. IF THE REST OF THE SUMMER IS ANY GUIDE...I
WOULD FAVOR THE LATTER SOLUTION FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1118 PM CDT SUN AUG 17 2014
WIDELY SCATTERED SHOWERS LATE THIS EVENING WILL BE FOLLOWED BY A
MORE ORGANIZED AREA OF ACTIVITY OVERNIGHT. PREFER THE RAP 0.5KM
AGL CONDENSATIONAL PRESSURE DEFICITS AS A GUIDE FOR CIGS IN THE
NEAR-TERM. THINK IFR CIGS/VSBYS WILL PLAGUE SITES INTO MID MORNING
MONDAY. THEN OCCASIONAL SHOWERS/TS ARE EXPECTED AS THE TROUGH
PASSES ACROSS TOMORROW. EAST/SOUTHEAST WINDS AHEAD OF THE WARM
FRONT...THEN SHIFT TO WEST/SOUTHWEST FOR TOMORROW. SPEEDS AROUND
OR BELOW 10 KTS THROUGH THE PERIOD.
KMSP...
CIGS ARE EXPECTED TO DECREASE OVERNIGHT WITH BKN-OVC IFR LEVEL
CIGS PERSISTING INTO MONDAY MORNING. SCATTERED SHRA/TS ARE
EXPECTED ON MONDAY. WIND SPEEDS STAY AOB 10 KTS THROUGH THE
PERIOD BUT SHIFT FROM EAST/SOUTHEAST TO SOUTHWEST ON MONDAY
MORNING.
/OUTLOOK FOR KMSP/
TUE...VFR. CHC MVFR WITH AFTERNOON TSRA. WINDS NW 5-10 KTS.
WED...VFR. WIND VRB AT 5KTS.
THU...VFR. CHC MVFR WITH TSRA. WINDS SSE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CLF
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1242 AM CDT MON AUG 18 2014
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 258 PM CDT SUN AUG 17 2014
THE MAIN FOCUS OF THIS FORECAST IS CENTERED AROUND A LOW-AMPLITUDE
SHORTWAVE TROUGH MAKING ITS WAY INTO THE NORTHERN/CENTRAL PLAINS.
HIGH INSTABILITY HAS DEVELOPED OVER OUR AREA AHEAD OF THIS TROUGH
WITH 3-5 J/KG CAPE INDICATED. WITH ERODING CAP AND TRENDS SHOWING
STRONGER BULK SHEAR AT 0-6KM IN THE 30 TO 35 KT RANGE THIS
EVENING...WE ARE POISED FOR SOME SEVERE WEATHER DEVELOPMENT. AN AREA
OF THUNDERSTORMS OVER NORTH CENTRAL NEBRASKA HAS ALREADY BECOME
STRONG ENOUGH TO WARN ON...WITH A CU FIELD DEVELOPING SOUTH OF
THIS INITIAL DEVELOPMENT. I EXPECT A BLOSSOMING OF THUNDERSTORMS
ALONG THE APPROACHING TROUGH THIS EVENING AND INTO THE OVERNIGHT.
WITH DECREASING INSTABILITY PAST MID-EVENING...IT MAY BE MORE
DIFFICULT TO PRODUCE SEVERE WEATHER...BUT NOT OUT OF THE QUESTION.
MODEST LOW- LEVEL JET NEAR 25 KTS WILL DEVELOP THIS EVENING THAT
COULD HELP SUSTAIN THUNDERSTORM ACTIVITY. THERE IS SOME AGREEMENT
BETWEEN THE HRRR AND WRF SOLUTIONS OF A POTENTIAL MCS TO SWING
THROUGH ROUGHLY THE NORTHERN HALF OF THE CWA. WITH EXPECTED SEVERE
PARAMETERS...WE COULD BE FAIRLY BUSY...AT LEAST FOR THE EVENING.
MOST OF THE CONVECTION SHOULD CLEAR THE CWA DURING THE OVERNIGHT
AS THE TROUGH CONTINUES EAST.
MONDAY SHOULD BE MAINLY DRY...BUT THE NAM IS INDICATING ANOTHER
PERTURBATION THAT COULD AFFECT THE SOUTHERN CWA IN KANSAS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 258 PM CDT SUN AUG 17 2014
THE LONG TERM BEGINS VERY SUMMER-LIKE AND ENDS WITH SOME POTENTIAL
FOR A MORE WIDESPREAD PRECIPITATION DEVELOPMENT BY NEXT WEEKEND.
HOWEVER...THE DETAILS ARE VERY SKETCHY BEYOND ABOUT WEDNESDAY
REGARDING TIMING/LOCATION OF PRECIPITATION TOWARD THE END OF THE
WEEK.
THE MOST INTERESTING PART OF THE UPPER LEVEL WEATHER PATTERN
WILL BE CHANGES COMING NEXT WEEKEND. MODEL GUIDANCE IN GENERAL
IS FAIRLY CONSISTENT THE CENTRAL PLAINS WILL SEE THE FLOW
TRANSITION TO AN UPPER TROUGH BY SOMETIME NEXT WEEKEND. THAT
HAS THE POTENTIAL TO BRING COOLER WEATHER AND A DECENT SHOT
FOR PRECIPITATION AT THAT TIME.
IN THE MEAN TIME...MUCH OF THE WEEK IS QUITE SUMMER-LIKE
IN TERMS OF TEMPERATURES. LOOK FOR TEMPERATURES TO BE
SLIGHTLY ABOVE NORMAL THROUGH PROBABLY THURSDAY...IF NOT
FRIDAY. NORTH CENTRAL KANSAS WILL SEE TEMPERATURES WELL
INTO THE 90S ALL WEEK. FORTUNATELY THERE WILL BE A SHORT BREAK
FROM HIGHER HUMIDITY LEVELS MONDAY NIGHT AND TUESDAY. MOISTURE
WILL START TO INCREASE AGAIN LATER IN THE WEEK AS THE UPPER
TROUGH APPROACHES AND SOUTHERLY WINDS INCREASE.
PRECIPITATION-WISE...MOST SOLD ON LATE TUESDAY NIGHT AND
EARLY WEDNESDAY WITH OVERNIGHT CONVECTION IN FACE OF STRONG
WARM ADVECTION AND 40KT LOW LEVEL JET. COVERAGE DEFINITELY
FAVORS NORTHERN AREAS...AND MAYBE EVEN NORTH OF OUR FORECAST
ALL TOGETHER. TIGHTENED UP THE PRECIPITATION CHANCES IN THE
AREA WITH THIS IN MIND. HOWEVER...AM NOT EXPECTING MORE
THAN A TENTH OR TWO OF RAIN AT MOST.
DID NOT STRAY AT ALL FROM DAYS 4-7 GUIDANCE GIVEN TO US IN THE
GRIDS...PRIMARILY BECAUSE CONFIDENCE IS NOT HIGH ENOUGH TO MAKE
SIGNIFICANT CHANGES. THE GENERAL TREND IS FOR INCREASING STORM
CHANCES BEGINNING THURSDAY NIGHT AND INTO THE WEEKEND. TEMPERATURES
COULD START TO DROP A BIT NEXT WEEKEND SHOULD PRECIPITATION
MATERIALIZE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1240 AM CDT MON AUG 18 2014
PLENTY OF MID AND HIGH LEVEL CLOUD COVER IS PERSISTING ACROSS THE
REGION EARLY THIS MORNING...AND AS SKIES CLEAR FROM WEST TO
EAST...COULD SEE SOME LIGHT BR FORM TO OUR WEST...POTENTIALLY
IMPACTING KEAR WITH SOME MVFR BR AROUND SUNRISE.
OTHERWISE...GENERALLY LIGHT SOUTHEASTERLY WINDS OVERNIGHT WILL
SHIFT AND BECOME NORTHERLY DURING THE DAY ON MONDAY...WITH VFR
CONDITIONS EXPECTED THROUGH THE PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...MORITZ
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1151 PM CDT SUN AUG 17 2014
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT SUN AUG 17 2014
...OUR PATTERN REMAINS UNSETTLED...AND WARMER THIS WEEK...
FORECAST CHALLENGES FOR THE SHORT TERM WILL BE THUNDERSTORM
CHANCES AND SEVERE POTENTIAL TONIGHT THROUGH MONDAY EARLY
AFTERNOON.
IT LOOKED FAIRLY QUIET WEATHER TO BEGIN THIS EVENING...HOWEVER IT
SEEMS LIKE THE SHORT RANGE MODELS ARE A BIT UNDERDONE WITH THE
CONVECTION OVER CENTRAL SOUTH DAKOTA BASES ON THE LATEST RADAR.
THE HRRR HAS A SHORTWAVE AND CONVECTION THAT DROPS SOUTHEAST
ACROSS THE FORECAST AREA. THIS EVENING...WHILE THE OTHER MODELS
ARE SLOWER AND LESS AGGRESSIVE UNTIL LATER TONIGHT. EVEN THE 18Z
NAM IS STILL DRY THIS EVENING. NOT SURE HOW HIGH TO GO EARLY...BUT
WILL INCLUDE ISOLATED THUNDERSTORMS FOR PARTS OF NORTHEAST
NEBRASKA EARLY THIS EVENING. THE STORM PREDICTION CENTER DOES HAVE
A SEVERE THUNDERSTORM WATCH OUT FOR COUNTIES JUST TO THE WEST OF
OUR FORECAST AREA THIS EVENING AND THE SLIGHT RISK FOR SEVERE
WEATHER DOES CLIP OUR WESTERN FORECAST AREA COUNTIES.
THE 12Z UPPER AIR MAPS SHOWED A RIDGE OVER THE SOUTHWEST U.S. WITH A
CLOSED LOW OVER SASKATCHEWAN AND LEADING SHORTWAVE TROF ENERGY OVER
MINNESOTA. THE STRONGER HEIGHT FALLS AT H5 WERE NOTED OVER
CANADA...ASSOCIATED WITH THIS NORTHERN SYSTEM. THERE WERE RIBBONS
OF POOLED H7 MOISTURE OVER THE PLAINS WITH THE H7 THERMAL RIDGE OVER
WESTERN NEBRASKA AND COLORADO. SIMILAR PATTERNS WERE NOTED AT H85.
THE OAX SOUNDING HAD A PWAT OF 1.44 INCHES WHICH WAS 134% OF NORMAL.
A MAX OF 185% OF NORMAL WAS CENTERED OVER KMPX.
AS THE EVENING PROGRESSES...A LOW LEVEL JET INCREASES TO 35-40KTS
OVER CENTRAL NEBRASKA...MEANWHILE THE SHORTWAVE TROF ENERGY OVER
CANADA EXTENDS SOUTHWARD INTO THE PLAINS. UPPER LEVEL JET
SUPPORT...OMEGA... FRONTOGENESIS AND THETA-E ADVECTION ALL
INCREASE. AS A RESULT...THE DETERMINISTIC MODELS INCREASE
CONVECTION OVER THE DAKOTAS AND THIS CONVECTION EXTENDS SOUTHWARD
INTO EASTERN NEBRASKA AND IOWA TONIGHT AND MONDAY. THERE IS A
GOOD H7 WARM AIR ADVECTION SIGNAL AND GOOD 7-8 DEG C H7 DEWPOINTS.
EXPECTED TRENDS LATER TONIGHT ARE WELL HANDLED BY THE CURRENT
FORECAST WITH INCREASING POPS INTO THE LIKELY CATEGORY AND WILL
TREND FARTHER SOUTH TO COVER POTENTIAL FOR INCREASED CONVERGENCE
CLOSER TO THE SURFACE LOW.
DEEP LAYER SHEAR IS FROM 30- 40KTS TONIGHT...HOWEVER DROPS CLOSER
TO 30KTS MONDAY. THE SURFACE AND H85 FRONT ARE STILL IN EASTERN
NEBRASKA MONDAY MORNING...AND GRADUALLY PUSH OUT OF THE FORECAST
AREA BY 00Z MONDAY. INSTABILITY IS 500-2000J/KG TONIGHT...BUT
INCREASES TO 3000+ MONDAY. FORECAST SOUNDINGS LOOK TO FAVOR
ELEVATED STORMS TONIGHT...HOWEVER THEY ARE MORE SURFACE BASED FOR
MONDAY. ALTHOUGH FREEZING LEVELS ARE HIGHER AND INSTABILITY IS
O.K. STRONGER SHEAR...PLUME OF STEEPER LAPSE RATES AND BETTER LOW
AND MID LEVEL FORCING MAY SUPPORT SOME SEVERE STORMS. SEVERE
WEATHER CHANCES CONTINUE INTO MONDAY AS THUNDERSTORMS WILL BE
ONGOING WITH INCREASED INSTABILITY...ALTHOUGH FORCING AND SHEAR
APPEAR TO BE NOT AS HIGH. TREND WITH HIGHER POPS IN THE
AM...DECREASING FROM WEST TO EAST IN THE AFTERNOON. STORM MOTION
IS AROUND 20KTS...BUT WITH HIGH PWATS/H7 DEWPOINTS AND POTENTIAL
FOR STORMS MOVING OVER THE SAME AREA COULD PRODUCE HEAVY RAIN.
MAINLY DRY FOR MONDAY NIGHT INTO TUESDAY WITH A WARM FRONT
SITUATED OVER NORTHERN KANSAS. THERE IS LIFT OVER THE FRONT AND
THE FRONT LIFTS NORTH TUESDAY NIGHT AND WEDNESDAY...SO HAVE
SCATTERED THUNDERSTORMS MENTIONED. WARMER HIGHS IN THE 90S CAN BE
EXPECTED SOUTH OF THE FRONT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 305 PM CDT SUN AUG 17 2014
STILL QUITE A FEW MODEL DIFFERENCES WEDNESDAY NIGHT THROUGH
SUNDAY. IT LOOKS LIKE A FRONT WILL BE IN THE AREA WEDNESDAY NIGHT
THROUGH FRIDAY...WITH A MID LEVEL RIDGE TO OUR SOUTH AND A
FLATTER...TROF INFLUENCE TO OUR NORTH. WARM H85 TEMPS FROM 20-24
DEG C PERSIST THROUGH FRIDAY NIGHT...HOWEVER THE EC BRINGS COOLER
WEATHER IN FOR SATURDAY...WHILE THE GFS HOLDS OFF UNTIL SUNDAY
NIGHT.
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1150 PM CDT SUN AUG 17 2014
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO PUSH THROUGH LNK AND OMA
SITES EARLY IN THE PERIOD. BEHIND THE RAIN MVFR VSBYS WILL BE
POSSIBLE AT BOTH OFK AND OMA AS LIGHT WINDS AND AMPLE MOISTURE ALLOW
FOG TO FORM. A FRONTAL BOUNDARY WILL THEN MAKE ITS WAY THROUGH THE
REGION TOMORROW MORNING...BRINGING VFR CONDITIONS AND GRADUALLY
TURNING WINDS TO THE NORTH MONDAY AFTERNOON.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...ZAPOTOCNY
LONG TERM...ZAPOTOCNY
AVIATION...KG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1251 AM CDT MON AUG 18 2014
.UPDATE...
ISSUED AT 1240 AM CDT MON AUG 18 2014
HAVE DROPPED POPS ALL BUT THE FAR EAST FOR THE REST OF THE OVERNIGHT.
UPDATE ISSUED AT 1000 PM CDT SUN AUG 17 2014
WILL ALLOW SEVERE THUNDERSTORM WATCH 463 TO EXPIRE AT 10 PM.
DISORGANIZED CONVECTION CONTINUES ACROSS EASTERN PORTIONS OF
DICKEY AND LAMOURE COUNTIES...AND SHOULD BE MOVING OUT OF THE AREA
IN THE NEXT HOUR OR TWO. ISOLATED SHOWERS ARE DIMINISHING ACROSS
CENTRAL NORTH DAKOTA BUT WILL KEEP A SLIGHT CHANCE HERE THROUGH
MIDNIGHT. ANOTHER AREA OF CONVECTION WAS LOCATED OVER SOUTH
CENTRAL SASKATCHEWAN INTO FAR NORTHEAST MONTANA...POISED TO MOVE
INTO NORTHWEST NORTH DAKOTA. THIS AREA IS CLOSER TO THE UPPER LOW.
THE 00 UTC NAM...LATEST HRRR AND RAP INDICATE THIS WEAK CONVECTION
COULD HOLD TOGETHER PAST MIDNIGHT...THUS WILL KEEP A SLIGHT CHANCE
IN THE NORTHWEST PAST MIDNIGHT. WILL CONTINUE TO KEEP A CHANCE
THROUGH THE NIGHT OVER THE FAR SOUTHEAST CWA FOR NOW AS COLD FRONT
REMAINS BACK ACROSS CENTRAL NORTH DAKOTA. LATER SHIFTS MAY BE ABLE
TO CUT THIS BACK IF NO ADDITIONAL CONVECTION DEVELOPS.
UPDATE ISSUED AT 847 PM CDT SUN AUG 17 2014
REMOVED ANOTHER ROW OF COUNTIES FROM THE WESTERN PORTION OF THE
SEVERE THUNDERSTORM WATCH...PIERCE...SHERIDAN AND EMMONS. ALSO
TRIMMED BACK POPS A BIT OVER WESTERN NORTH DAKOTA. WILL TAKE A
CLOSER LOOK AT POPS WITH THE 10 PM UPDATE.
UPDATE ISSUED AT 643 PM CDT SUN AUG 17 2014
REMOVED HETTINGER...ADAMS...GRANT...MORTON...MERCER AND OLIVER
COUNTIES FROM SEVERE THUNDERSTORM WATCH 463. SEE THE RECENTLY
ISSUED SPC MESOSCALE DISCUSSION 1565 FOR DETAILS ON EXPECTED
TRENDS THROUGH 0045 UTC.
UPDATE ISSUED AT 401 PM CDT SUN AUG 17 2014
QUICK UPDATE TO ISSUE SEVERE THUNDERSTORM WATCH 463 VALID THROUGH
10 PM CDT.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 315 PM CDT SUN AUG 17 2014
SEVERE CONVECTION WILL HIGHLIGHT THE SHORT TERM FORECAST FOR THIS
AFTERNOON AND EVENING.
OVERALL...IN AGREEMENT WITH SPC THINKING FOR CONVECTIVE EVOLUTION
THE REMAINDER OF THIS AFTERNOON AND EVENING. SEE SPC MESOSCALE
DISCUSSION #1563 FOR DETAILS. IN GENERAL...SOME UNCERTAINTY EXISTS
ON HOW MUCH CONVECTION WILL FILL IN ALONG THE COLD FRONT CROSSING
US HIGHWAY 85 AS OF 20 UTC...AS THE 17 AND INCOMING 18 UTC HRRR
ITERATIONS SHOW LITTLE BETWEEN THE ONGOING STORMS ACROSS THE NORTH
CENTRAL AND SOUTHWEST. THIS IS IN OPPOSITION TO THE 12 UTC WRF-ARW
AND NMM AND GLOBAL GUIDANCE WHICH WOULD SUGGEST MORE WIDESPREAD
STORMS BY 21-00 UTC. LARGE HAIL AND DAMAGING WINDS ARE THE PRIMARY
THREATS. WHILE LOW LEVEL SHEAR IS WEAK...CANNOT RULE OUT AN
ISOLATED TORNADO GIVEN POTENTIAL DISCRETE SUPERCELL STRUCTURES.
STORMS SHOULD BE LARGELY INTO THE RED RIVER VALLEY BY 03 UTC. NON-
SEVERE SCATTERED THUNDERSTORMS WILL CONTINUE NORTHWEST THROUGH
SUNSET...IN ASSOCIATION WITH THE UPPER LOW ALOFT.
FOR MONDAY...ADDITIONAL ISOLATED TO SCATTERED STORMS...BEST
CHANCES EAST...WILL LINGER GIVEN COLD TEMPERATURES ALOFT WITH THE
UPPER LEVEL LOW DEPARTING INTO MINNESOTA.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 315 PM CDT SUN AUG 17 2014
AN ACTIVE WEATHER PATTERN WITH BELOW NORMAL TEMPERATURES WILL
HIGHLIGHT THE EXTENDED FORECAST.
AFTER A DRY TUESDAY...THE 12 UTC GUIDANCE SUITE IS IN AGREEMENT ON
A BROAD UPPER LEVEL TROUGH ESTABLISHING ITSELF ACROSS THE PACIFIC
NORTHWEST INTO THE NORTHERN PLAINS. THIS SUPPORTS A RATHER ACTIVE
WEATHER PERIOD WITH DAILY CHANCES FOR SHOWERS AND THUNDERSTORMS
WEDNESDAY THROUGH THE WEEKEND. TEMPERATURES ARE ALSO EXPECTED TO
BE BELOW NORMAL AS A RESULT...POSSIBLY ONLY IN THE MID TO UPPER
60S FOR SOME LOCATIONS BY NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1240 AM CDT MON AUG 18 2014
AN UPPER LEVEL TROUGH WILL MOVE SOUTHEAST FROM ITS CURRENT LOCATION
OVER NORTH CENTRAL NORTH DAKOTA...INTO WESTERN WISCONSIN THROUGH THE
06 UTC TAF PERIOD. GREATEST THREAT FOR LATE MORNING AND AFTERNOON
THUNDER WILL BE AT KBIS AND KJMS...THUS THESE ARE THE ONLY TAFS WITH
A MENTION OF THUNDER AT THIS TIME. DID MENTION A VCSH AT KMOT AND
KDIK. MODELS ARE INDICATING SOME WRAP AROUND LOW LEVEL MOISTURE
DROPPING SOUTH INTO THE FORECAST AREA BEHIND THE UPPER LOW LATE
TONIGHT AND EARLY MONDAY MORNING. MENTIONED A SCATTERED MVFR CLOUD
LAYER MOST AREAS MONDAY MORNING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...AYD
LONG TERM...AYD
AVIATION...TWH/JPM
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
116 AM EDT MON AUG 18 2014
.SYNOPSIS...
WEAK HIGH PRESSURE ATOP THE REGION THIS WEEKEND WILL GIVE WAY TO A
GRADUAL INFLUX OF MOISTURE ON MONDAY AND TUESDAY WITH IMPROVING
SOUTHWEST FLOW. A SERIES OF LOW PRESSURE SYSTEMS PASSING BY TO THE
NORTH WILL INCREASE THE CHANCES OF SHOWERS AND THUNDERSTORMS THROUGH
MIDWEEK...ESPECIALLY OVER THE MOUNTAINS.
&&
.NEAR TERM /THROUGH TODAY/...
0515 UTC UPDATE...WINDS WERE UPDATED WITH A BLEND OF THE NAM AND
ADJMAV...FAVORING THE FORMER BY TWO TO ONE TO ACCOUNT FOR GREATER
MOUNTAIN WINDS. POPS WERE ADJUSTED IN THE NC MOUNTAINS BASED ON
RADAR TRENDS TO THE WEST.
AS OF 930 PM...AS EXPECTED...PRECIP CONTINUES ITS WEAKENING
TREND...TO THE POINT WHERE ONLY A FEW PATCHES OF LIGHT RAIN AND
ISOLATED SHOWERS REMAINED ACROSS THE FCST AREA. WILL RETAIN A CHANCE
POP OVER THE NC MOUNTAINS...MAINLY S AND W OF I-40...TO ACCOUNT FOR
SHOWERS MOVING IN FROM SE TN. SOME MINOR ADJUSTMENTS WERE MADE TO
THE TEMP TREND BASED ON OBSERVATIONS.
REMAINDER OF PREVIOUS DISCUSSION...
MODELS SEEM TO DIFFER SOMEWHAT AT THIS POINT WITH THE 12Z HIRES WRF
PRODUCTS INDICATING A SECONDARY MCS DEVELOPING AND TRAILING THE
INITIAL LINE BY ABOUT 4-5 HOURS AND ENTERING THE MOUNTAIN ZONES JUST
AFTER MIDNIGHT. THAT SAID...THE HRRR AND LOWER RES 12Z NAM INDICATE
A LULL AS MENTIONED ABOVE WITH INITIAL MCS DECAY...WHICH WAS THE
PREFERRED SOLUTION IN THE FORECAST.
BY DAYBREAK EXPECTING COVERAGE OF SHOWERS AND PERHAPS A THUNDERSTORM
OR TWO TO BE INCREASING ACROSS MOST OF WESTERN NC...AND EVENTUALLY
SPREADING SOUTHEAST INTO THE NC/SC PIEDMONTS BY LATE MORNING INTO
EARLY AFTERNOON. PROFILES LOOK FAIRLY MOIST WHICH WILL INHIBIT
DIURNAL HEATING SOMEWHAT HOWEVER THERE WILL BE NEARLY 1000J/KG
SBCAPE PRESENT BY LATE MORNING. THUS CANNOT RULE OUT A STRONG TO
PERHAPS ISOLATED SEVERE THUNDERSTORM BEFORE THE PRIMARY UPPER
FORCING MECHANISM MOVES OUT LEAVING ONLY THERMODYNAMIC EFFECTS IN
PLAY. ONE ADDITIONAL NOTE...AS MENTIONED ABOVE PROFILES WILL BE
ABUNDANTLY MOIST THEREFORE ANY THUNDERSTORMS COULD PRODUCE
SUBSTANTIAL RAIN RATES LEADING TO MINOR FLASH FLOODING. FORTUNATELY
DUE TO 30-40KTS OF WESTERLY H5 FLOW AND CONTINUED SOUTHWESTERLY FLOW
BENEATH...IT DOES NOT LOOK AS IF ANY CELLS WILL ANCHOR. CONDITIONS
WILL SLOWLY IMPROVE TOWARDS THE LATE AFTERNOON ACROSS THE SOUTHWEST
WITH THE NORTHEASTERN ZONES TO FOLLOW AS THE WAVE DEPARTS. AS FOR
THE FORECAST...CHANCE POPS ARE FEATURED ACROSS THE MOUNTAINS WITH
ONLY SLIGHT CHANCE POPS ACROSS THE FOOTHILLS FOR THIS AFTERNOON AND
EVENING. POPS ON MONDAY WILL FEATURE LIKELY LEVELS ACROSS MUCH OF
WESTERN NC WITH SOLID CHANCE LEVEL POPS ELSEHWERE. TEMPERATURES WILL
BE COOLER ON MONDAY AS PARTLY/MOSTLY CLOUDY SKIES PREVAIL YIELDING
BELOW NORMAL TEMPERATURES.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
AS OF 255 PM SUNDAY...NEARLY ZONAL FLOW REMAINS ACROSS THE AREA THRU
THE PERIOD AS AN UPPER LOW MOVES TO THE GREAT LAKES AND A RIDGE
BUILDS OVER THE LOWER MS RIVER VALLEY AND GULF COAST. A SHORT WAVE
TO THE SOUTH MOVES INTO THE AREA TUE...ANOTHER SHORT WAVE MOVES
ACROSS THE NORTH TUE NITE WITH ANOTHER WEAK WAVE ACROSS THE AREA
WED. AT THE SFC...A QUASI STATIONARY FRONT REMAINS TO OUR NORTH WITH
A LEE TROF NEAR THE FALL LINE. THERE WILL BE WAVES OF MOISTURE
MOVING INTO THE AREA WITH THE WAVES...ALMOST MCS LIKE. HOWEVER...
THERE IS QUITE A BIT OF SPREAD IN THE GUIDANCE SOLUTIONS REGARDING
CONVECTIVE COVERAGE. IN ADDITION...THERE IS LITTLE IN THE WAY OF LOW
LEVEL SLY FLOW WITH LOW LEVEL RIDGING KEEPING THE WINDS MORE WLY.
ALSO...LFC LEVELS REMAIN HIGH ACROSS THE SOUTH...BUT DO LOWER ACROSS
THE MTNS AND NRN TIER WHERE LOW LEVEL MOISTURE INCREASES THE MOST.
THERE IS QUITE A BIT OF ELEVATED INSTABILITY HOWEVER...SO ANY
FORCING THAT CAN LIFT THE PARCELS TO THAT LEVEL WILL ALLOW CONVECTION
TO BE REALIZED. THEREFORE...HAVE CONTINUED THE PREV TREND OF HIGHEST
POP MTNS AND NRN TIER THRU THE PERIOD...WITH A DIURNAL TREND. THAT
SAID...KEEP POP ACROSS THE MTNS OVERNIGHT TO ACCOUNT FOR ANY MCS
ACTIVITY THAT DOES MAKE IT THIS FAR EAST. LOWS WILL REMAIN NEARLY
STEADY A LITTLE ABOVE NORMAL. HIGHS WILL BE NEAR TO SLIGHTLY ABOVE
NORMAL TUE...THEN WARM A COUPLE OF DEGREES WED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 2 PM EDT SUNDAY...THE MEDIUM RANGE PICKS UP AT 00Z ON THURSDAY
WITH RELATIVELY FLAT UPPER RIDGING OVER THE SE CONUS AND A HEALTHY
LOOKING UPPER SHORTWAVE CROSSING THE SOUTHERN GREAT LAKES TO OUR
NORTH. OVER THE NEXT COUPLE OF DAYS...THE LONG RANGE MODELS HAVE THE
UPPER RIDGE RETROGRADING BACK TOWARDS THE WEST WHILE THE ABOVE
SHORTWAVE BECOME ABSORBED BACK INTO MEAN UPPER FLOW AND A BROADER
UPPER TROF DEVELOPS JUST OFF THE NEW ENGLAND COAST. FOR THE
REMAINDER OF THE PERIOD...THE RIDGE AXIS REMAINS IN PLACE TO OUR
WEST WHILE THE UPPER TROF BECOMES NEARLY STATIONARY AND MORPHS INTO
A CLOSED H5 LOW BY DAY 7.
AT THE SFC...OUR AREA IS EXPECTED TO REMAIN UNDER A WARM AND MOIST
AIR MASS THRU THE PERIOD WITH WEAK HIGH PRESSURE IN PLACE AND A
SERIES OF WEAK MESO LOWS THAT TRY TO SPIN UP TO OUR NORTH AND EAST.
AS WOULD BE EXPECTED...MODEL PLACEMENT AND TIMING OF THESE LOWS IS
SPORADIC BETWEEN RUNS WITH THE DEEPER LYR MOISTURE ASSOCIATED WITH
THE NEAR SFC FEATURES GENERALLY CONFINED TO OUR NORTH AND EAST. THE
DEEPER MOISTURE APPEARS TO SPREAD MORE TO THE WEST OVER THE WEEKEND
SO SAT AND SUN SHOULD BE OUR BEST SHOT AT WIDESPREAD DIURNAL
CONVECTION. OTHERWISE...POPS FOLLOW A TYPICAL LATE SUMMERTIME
DIURNAL SLIGHT CHANCE TO CHANCE. TEMPS WILL START OUT ABOUT A
CATEGORY ABOVE NORMAL ON THURS AND STEADILY COOL THRU DAY 7 WITH
VALUES ENDING RIGHT AROUND CLIMO.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
AT KCLT...MODEL TIME HEIGHTS SHOW LOW VFR CLOUDS...WITH AN EVEN
LOWER LAYER AROUND DAYBREAK. WITH MODEL GUIDANCE DIFFERING ON JUST
HOW LOW DAYBREAK CIGS WILL BE...ONLY A VERY LOW VFR CIG WILL BE
CARRIED AT DAYBREAK. A GUIDANCE CONSENSUS ONLY LOWERS VSBY TO LOW
VFR BY DAYBREAK...BUT THE CONSENSUS DOES LOWER VSBY TO IFR TO THE
W...AND MVFR TO THE S AND N. CONVECTIVE CHANCES WILL WARRANT A
MENTION IN THE TAF ON TODAY...AS A MID LEVEL SYSTEM CROSSES THE
AREA. SW WINDS WILL PREVAIL...WITH SOME GUSTINESS DURING DAYLIGHT
HOURS.
ELSEWHERE...CONVECTION OVER E TN IS NOT EXPECTED TO SURVIVE THE LOSS
OF HEATING LONG ENOUGH TO REACH KAVL. MODEL TIME HEIGHTS ARE SHOWING
LOW CLOUDS...BUT NO FIRM CONSENSUS ON HOW LOW THEY WILL BE AT
DAYBREAK. FOR NOW A BLEND WILL BE USED...BRINGING CIGS TO LOW VFR BY
DAWN...EXCEPT MVFR AT KAVL. A BLEND OF GUIDANCE SUPPORTS MVFR VSBY
AT DAYBREAK. CONVECTIVE CHANCES WILL BE MUCH BETTER TODAY THAN
RECENTLY AS A MID LEVEL SYSTEM CROSSES THE AREA. SW WINDS WILL
PREVAIL...WITH GUSTINESS DURING DAYTIME HEATING...BUT WINDS SHOULD
CHANNEL UP VALLEY FORM THE NW AT KAVL.
OUTLOOK...UPPER LEVEL RIDGING WILL SET IN BY MIDWEEK WITH ENOUGH
MOISTURE IN THE PROFILE TO SUPPORT DIURNAL CONVECTION THROUGH WEEKS
END LEADING TO AFTERNOON TSRA RESTRICTIONS AND POSSIBLE EARLY
MORNING FOG.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 83% HIGH 86% HIGH 100% HIGH 100%
KHKY HIGH 98% HIGH 90% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 95% HIGH 100% HIGH 100% 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...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...CDG/JAT/PM
SHORT TERM...RWH
LONG TERM...JPT
AVIATION...JAT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
324 AM CDT MON AUG 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT MON AUG 18 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED TROUGHING FROM LAKE WINNIPEG INTO THE DAKOTAS AND RIDGING
OVER MICHIGAN. BETWEEN THESE TWO FEATURES...THERE WERE SHORTWAVES
NEAR LA CROSSE AND IN SOUTHEAST SOUTH DAKOTA. DPVA FROM THE FORMER
SHORTWAVE...COMBINED WITH A ZONE OF 850MB MOISTURE TRANSPORT WHICH
EXTENDED FROM NORTH CENTRAL IA INTO NORTH CENTRAL WI...HAS RESULTED
IN SCATTERED TO NUMEROUS CONVECTION OVER THE NORTHWEST HALF OF THE
FORECAST AREA. PRECIPITABLE WATER VALUES FROM THE RAP SHOW VALUES OF
1.5-1.8 INCHES IN GENERAL...HIGHEST WITHIN THE CONVECTION. THESE
HIGH VALUES HAS ALLOWED CONVECTION TO HAVE HEAVY RAINFALL RATES...
WITH UPWARDS OF 2 INCHES PER HOUR FROM THE ONE THAT WENT THROUGH THE
ROCHESTER AREA LATE LAST EVENING. TO THE WEST...ANOTHER ZONE OF 1.5-
1.8 INCH PRECIPITABLE WATER WAS PRESENT OVER FAR WESTERN MN...AHEAD
OF THE DAKOTAS UPPER TROUGH AND SOUTHEAST SOUTH DAKOTA SHORTWAVE.
DPVA FROM THESE FEATURES ACTING ON THE MOISTURE RESULTING IN
ISOLATED SHOWER AND STORM ACTIVITY IN FAR WESTERN MN TOO.
THE UPPER TROUGH FROM LAKE WINNIPEG INTO THE DAKOTAS REMAINS ON
TRACK TO MOVE INTO THE FORECAST AREA TONIGHT. PRETTY MUCH ALL DAY
TODAY THROUGH THE EVENING HOURS THE FORECAST AREA IS UNDER FALLING
500MB HEIGHTS. COMBINE THIS WITH A SERIES OF SHORTWAVES COMING
THROUGH FROM THE TROUGH SUCH AS THAT ONE IN SOUTHEAST SOUTH
DAKOTA...THE 1.5-1.8 INCH PRECIPITABLE WATER AIRMASS IN PLACE...AND
DAYTIME HEATING TO ADD EVEN MORE INSTABILITY...RESULTS IN A VERY
FAVORABLE SETUP FOR CONVECTION. THE MAJORITY OF THE FORECAST AREA
SHOULD SEE RAIN OVER THE NEXT 18 HOURS...WITH CORRIDORS OF HEAVIER
RAIN POSSIBLE DUE TO THE HIGH PRECIPITABLE WATER VALUES.
SPECIFICALLY TIMING THE WET AND DRY PERIODS IS VERY PROBLEMATIC...
BUT IN GENERAL IT SEEMS AS IF THERE COULD BE A DRY PERIOD AROUND MID-
MORNING. THIS WOULD CORRELATE WITH THE WEAKENING OF THE LOW LEVEL
JET AND A PERIOD OF SUBSIDENCE BETWEEN THE DEPARTING LA CROSSE
SHORTWAVE AND THE OTHER SHORTWAVE COMING IN FROM THE SIOUX FALLS.
WELL SEE. THE AFTERNOON INTO THE EARLY EVENING HOURS CERTAINLY BODE
WELL FOR CONVECTION WITH THE DAYTIME INSTABILITY HELP...THUS HIGHEST
CHANCES ARE CENTERED THEN. EVEN DURING THIS TIME FRAME...THERE COULD
BE 2-3 HOUR BREAKS BETWEEN ROUNDS OF CONVECTION. ANOTHER SPECIFIC
NOTE...IT WOULD APPEAR THE SOUTHEAST END OF THE FORECAST AREA MAY
NOT GET HIT WITH MUCH CONVECTION UNTIL LATE AFTERNOON OR THE EVENING
HOURS.
LOOK FOR THE CONVECTION TO PUSH OFF TO THE EAST LATE THIS
EVENING THROUGH THE OVERNIGHT HOURS...DUE TO A COMBINATION OF
SUBSIDENCE WORKING IN FROM THE WEST WITH THE TROUGH MOVING IN
PLACE...AS WELL AS LOSS OF DAYTIME HEATING DIMINISHING INSTABILITY.
A COLD FRONTAL PASSAGE LOOKS TO OCCUR AS WELL TONIGHT TO AID IN THE
DIMINISHING TREND.
REGARDING SEVERE WEATHER POTENTIAL...LOOKING AT SHEAR...WE MAY
NEED TO WATCH THE LATE AFTERNOON AND EVENING HOURS. AT 00Z...THE 0-
3KM SHEAR CLIMBS TO 25 KT AROUND I-90 AND 30-35 KT IN NORTHEAST
IOWA. IF CONVECTION EXISTS INTO THESE REGIONS...THEY MAY HAVE
SOME SEVERE WIND POTENTIAL. OTHERWISE...WARM CLOUD DEPTHS UPWARDS OF
3000-3500 METERS WILL RESULT IN HEAVY RAIN AS THE MAIN CONCERN. HAVE
NOT ISSUED ANY FLASH FLOOD WATCH GIVEN ANTECEDENT DRY
CONDITIONS...HOWEVER...LOCALIZED FLOOD ADVISORIES OR WARNINGS MAY
BE NEEDED...ESPECIALLY IN URBAN AREAS WHICH CANNOT HANDLE
HIGHER RAINFALL RATES.
THE CONVECTION AROUND TODAY MAKES FOR A TRICKY HIGH TEMPERATURE
FORECAST. 925MB TEMPS CLIMBING TO 19-22C ON AN INCREASING SOUTHWEST
WIND COULD ALLOW FOR HIGHS OF 80-85 UNDER THE FULL SUN.
HOWEVER...HAVE TO HOLD THESE BACK AS MUCH AS 5 DEGREES OR SO TO
ACCOUNT FOR CONVECTION. WARMEST READINGS ARE LIKELY IN THE SOUTHEAST
END WITH THE LONGEST DRY PERIOD EXPECTED. LOWS TONIGHT EXPECTED ON
THE MILD SIDE AGAIN WITH THE COLD FRONTAL PASSAGE MAKING THE BIGGER
IMPACT TO LOWERING TEMPERATURES.
WITH THE PRECIPITATION ENDING DURING THE NIGHT TIME HOURS...FOG
POTENTIAL NEEDS TO BE CONSIDERED. HOWEVER...IT APPEARS THERE SHOULD
BE A DECENT WEST TO NORTHWEST BREEZE IN THE WAKE OF THE COLD FRONTAL
PASSAGE TO KEEP THE AIR MIXED...PREVENTING FOG FORMATION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 324 AM CDT MON AUG 18 2014
TUESDAY INTO TUESDAY NIGHT...MODELS TAKE THEIR SWEET TIME IN GETTING
THE UPPER TROUGH OUT OF THE REGION. HOWEVER...IT DOES LOOK TO GET A
DECENT PUSH EAST LATE TUESDAY NIGHT...RESPONDING TO UPPER RIDGING
BEING FORCED TO BUILD UP OVER THE DAKOTAS INTO MN. WHATS
INTERESTING DURING THIS TIME PERIOD IS SUGGESTIONS OF A SECONDARY
COLD FRONT DROPPING SOUTH THROUGH THE AREA DURING THE AFTERNOON AND
EVENING...CONNECTED WITH ANOTHER SHORTWAVE COMING THROUGH THE
TROUGH. HAVE MAINTAINED SOME PRECIPITATION CHANCES...HIGHEST OVER
NORTH CENTRAL WISCONSIN UNDER THE COOLER AIR ALOFT AND HIGHEST
PRECIPITABLE WATER. MUCH OF THE PRECIPITATION SHOULD END BY LATE
EVENING WITH LOSS OF DAYTIME HEATING AND UPPER TROUGH BEGINNING TO
PULL AWAY. IT SHOULD BE NOTED THE RAINFALL RATES ON TUESDAY DO NOT
LOOK NEARLY AS HIGH TODAY...A RESULT OF THE PRECIPITABLE WATER
VALUES ONLY IN THE 1-1.5 RANGE. LATE TUESDAY NIGHT...WE SHOULD GET A
SURFACE RIDGE OF HIGH PRESSURE TO BUILD INTO THE WESTERN 2/3 OF THE
REGION. SKIES SHOULD CLEAR AND WINDS WILL RELAX WITH THE RIDGE
COMING IN...SETTING UP CONDITIONS FAVORABLE FOR SOME FOG TO FORM.
DETAILS ON THE EXPANSE AND THICKNESS OF THE FOG WILL DEPEND EXACTLY
ON THE TIMING OF THE RIDGE COMING IN. DESPITE THE COLD FRONTAL
PASSAGE...925MB TEMPS ARE PROGGED PRETTY SIMILAR ON TUESDAY TO
TODAY. THE SOUTHERN FORECAST AREA SHOULD BE WARMEST GIVEN BETTER
MIXING POTENTIAL.
FOR WEDNESDAY INTO THURSDAY...MODELS BRING THAT UPPER RIDGING OVER
MN INTO THE FORECAST AREA. IT WOULD APPEAR ENOUGH SUBSIDENCE SHOULD
BE IN PLACE PRIOR TO THE RIDGE BUILDING IN TO YIELD A DRY DAY
WEDNESDAY. ADDITIONALLY...THE MAIN WARM FRONTAL BOUNDARY LOOKS TO BE
WELL TO THE SOUTH...ONLY NEAR THE MISSOURI/IOWA BORDER AT 00Z
THURSDAY. HOWEVER...THIS BOUNDARY LOOKS TO SURGE NORTHWARD TOWARDS
THE FORECAST AREA WEDNESDAY NIGHT...AND POSSIBLY COMPLETELY THROUGH
ON THURSDAY. A DECENT PUSH OF 850MB MOISTURE TRANSPORT INTO THE
BOUNDARY WILL INITIATE ELEVATED CONVECTION OVER THE SOUTHWEST
2/3 OF THE AREA. AGAIN HEAVY RAIN LOOKS TO BE A BIG CONCERN AS
PRECIPITABLE WATER CLIMBS BACK UP TOWARDS 2 INCHES...ALONG WITH A
FEED OF INSTABILITY INTO THE CONVECTION FROM THE LOW LEVEL JET...AND
POTENTIAL TO BE IN THE RIGHT ENTRANCE REGION OF A JET STREAK OVER
LOWER MICHIGAN. RIGHT NOW IT APPEARS THE BOUNDARY SHOULD CONTINUE TO
LIFT NORTHWARD...HELPING TO PREVENT A WIDER FLASH FLOOD THREAT...BUT
NEEDS TO BE WATCHED CLOSELY. ADDITIONALLY...CANNOT RULE OUT SOME
SEVERE WIND POTENTIAL FROM THE CONVECTION. CONVECTION SHOULD
DIMINISH LATE THURSDAY MORNING THROUGH THE AFTERNOON HOURS WITH THE
WEAKENING OF THE LOW LEVEL JET...AND AS CAPPING COMES IN ALOFT.
TEMPERATURES AFTER HOVERING IN THE MID 70S TO LOW 80S THROUGH
WEDNESDAY COULD MAKE A MAJOR BOOST ON THURSDAY. THERE IS POTENTIAL
ACCORDING TO THE 18.00Z ECMWF FOR LOCATIONS ALONG/WEST OF THE MS
RIVER TO GET CLOSE TO 90...ALL DEPENDING ON SUN AND WARM FRONTAL
BOUNDARY TRACK.
FOR THURSDAY NIGHT THROUGH THE WEEKEND...THE 500MB PATTERN FEATURES
UPPER RIDGING TO BEGIN THE PERIOD OVER THE AREA WHILE TROUGHING
EXISTS ACROSS THE PACIFIC NORTHWEST. MODELS ARE IN BETTER AGREEMENT
TODAY THAN YESTERDAY HANDLING THIS TROUGH...AND IT APPEARS SOME
OF THIS TROUGH WILL PUSH EAST INTO THE WEEKEND AND HELP SHIFT THE
RIDGE EASTWARD. THIS TRANSLATES INTO A STORM SYSTEM TO AFFECT THE
REGION FOR FRIDAY THROUGH THE WEEKEND. THE ASSOCIATED WARM FRONT
LOOKS TO LIFT INTO THE REGION ON FRIDAY...WHICH MAY OR MAY NOT
CONVECT DEPENDING ON CAPPING. A COLD FRONTAL PASSAGE COULD OCCUR ON
SATURDAY...FOLLOWED BY A LOW RIDING UP ALONG THE FRONT ON SUNDAY.
CONVECTION IS EASILY POSSIBLE ON BOTH OF THESE FEATURES.
THEREFORE...CHANCES OF SHOWERS AND THUNDERSTORMS LITTER MUCH OF THE
EXTENDED. PRIOR TO THE COLD FRONTAL PASSAGE...925MB TEMPS LOOK TO
RANGE FROM 22-26C...SUPPORTIVE OF 80S TO POSSIBLY 90...DEPENDING ON
AMOUNT OF SUN. AIRMASS APPEARS HUMID TOO. COOLER AIR THEN FILTERS
IN FOR SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1139 PM CDT SUN AUG 17 2014
SHOWERS AND STORMS CONTINUE TO REDEVELOP OVER SOUTHEAST MINNESOTA
LATE THIS EVENING IN AN AREA OF WEAK MOISTURE TRANSPORT AND
VERTICAL LIFT AHEAD OF A SHORT WAVE TROUGH COMING ACROSS
MINNESOTA. EXPECT THIS ACTIVITY TO CONTINUE FOR A FEW MORE HOURS
UNTIL THE SHORT WAVE TROUGH MOVES PAST THE AREA AND WILL INITIALLY
HAVE TEMPO GROUPS AND THE VCTS WHEN IT IS SHOULD BE MOVING OUT OF
THE AREA. CONFIDENCE IS HIGHEST THAT KRST WILL CONTINUE TO BE
IMPACTED AS THAT IS WHERE THE NOSE OF THE MOISTURE TRANSPORT IS.
THE RADAR SHOWS THE ACTIVITY WEAKENING AS IT APPROACHES THE
MISSISSIPPI RIVER AND WITH THE MOISTURE TRANSPORT NOT MOVING
MUCH...KLSE MAY NOT SEE A WHOLE LOT OF ACTIVITY SO WILL STAY WITH
VCTS THERE. THE 18.03Z RAP STILL INDICATES THAT LOW STRATUS AND
SOME FOG SHOULD FORM LATE TONIGHT ONCE THE RAIN ENDS...BUT
CONCERNED THAT THE WINDS MAY STAY UP A LITTLE TOO MUCH TO ALLOW
MORE THAN MVFR VISIBILITIES TO DEVELOP. STRATUS EXPECTED TO START
LIFTING LATE MONDAY MORNING WHICH IS WHEN THE NEXT SHORT WAVE
TROUGH WILL BE APPROACHING FROM THE WEST TO START THE NEXT ROUND
OF SHOWERS AND STORMS. FEEL THERE WILL NEED TO BE A PERIOD OF
CATEGORICAL THUNDER FOR BOTH TAF SITES...BUT CONFIDENCE ON WHEN
THIS WILL OCCUR IS TOO LOW TO INCLUDE IT RIGHT NOW. THE 18.00Z NAM
AND 17.12Z HI-RES ARW WOULD SUGGEST LATE AFTERNOON INTO THE
EVENING BUT WHAT IS IN OF THE 18.00Z HI-RES ARW SUGGESTS AS EARLY
AS 18Z MONDAY. WILL CONTINUE WITH VCTS UNTIL THE TRENDS BECOME
CLEARER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1139 PM CDT SUN AUG 17 2014
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 230 PM CDT SUN AUG 17 2014
LATEST WATERVAPOR IMAGERY POINTED TO A SHORTWAVE TROUGH MOVING
SLOWLY EAST ACROSS WESTERN MN...RESPONSIBLE FOR AN AREA OF
SHOWERS/STORMS ACROSS MID/EASTERN SECTIONS OF THE GOPHER STATE.
ANOTHER UPPER LEVEL SHORTWAVE TROUGH WAS SWINGING INTO THE NORTHERN
PLAINS.
THIS FIRST SYSTEM WILL CONTINUE TO MAKE SLOW PROGRESS EAST
TONIGHT...GRADUALLY TRACKING INTO NORTHERN WI. MODELS SUGGEST THAT
THIS FEATURE WILL WEAKEN AND/OR GET PULLED INTO THE NEXT
SHORTWAVE...WHICH WILL TAKE A SPEEDIER PATH ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY ON MONDAY. 25 KT 850 MB JET WILL PROVIDE A
PUSH OF LOW LEVEL MOISTURE FOR THE SYSTEM TO WORK ON MONDAY.
ALTHOUGH WARM CLOUD DEPTHS AREN/T AS DEEP AS RECENT DAYS - ITS STILL
FORECAST TO BE AROUND 3.5 KFT WITH PWS AROUND 1.6. SO...HEAVY RAIN
STILL A GOOD BET WITH ANY OF THE STRONGER STORMS. MUCAPES BUILD IN
EXCESS OF 2000 J/KG BY 00 TUE...WITH THE BULK OF THE SHEAR IN THE 0-
3KM LAYER NEAR 25 KTS. FAIRLY SKINNY CAPE PROFILES ACROSS THE
FORECAST AREA FOR THE MOST PART - PER BUFKIT SOUNDINGS - ALTHOUGH A
BIT MORE FAVORABLE FOR STORM DEVELOPMENT ACROSS NORTHEAST IA.
OVERALL...DON/T SEE AN ORGANIZED SEVERE WEATHER THREAT AT THIS TIME.
BELIEVE HEAVY RAIN AND A CHANCE FOR SMALL HAIL THE MORE LIKELY
OUTCOMES.
ON THE WHOLE...WILL HAVE SOME SCATTERED SHOWERS/STORMS INTO THE
EVENING HOURS FOR SOUTHEAST MN...WITH CHANCES MOSTLY ALONG AND NORTH
OF I-90 THROUGH THE OVERNIGHT. THE GREATER THREAT FOR RAIN WILL COME
LATER IN THE DAY ON MONDAY...AND MOST LOCATIONS CAN EXPECT TO GET
WET.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 230 PM CDT SUN AUG 17 2014
DECENT AGREEMENT IN THE MODELS WITH THE OVERALL PATTERN FOR THE
LATER PART OF THE NEW WEEK. THE GFS/ECMWF POINT TO A FAIRLY
PROGRESSIVE PATTERN WITH SOME MINOR RIDGE BUILDING FRI. BOTH SLIDE
AN UPPER LEVEL SHORTWAVE TROUGH ACROSS THE NORTHERN PLAINS
WED...TRACKING NORTH OF THE REGION ON THU. AN ASSOCIATED SFC WARM
FRONT WILL LIFT ACROSS THE UPPER MISSISSIPPI RIVER VALLEY...WITH
FRONTOGENETIC LIFT AND WARM AIR ADVECTION ALONG IT LIKELY
RESULTING IN A BAND OF SHOWERS/STORMS.
ANOTHER SHORTWAVE TROUGH IS SLATTED TO MOVE OUT OF THE SOUTHERN
ROCKIES AND TAKE AIM ON THE UPPER MISSISSIPPI RIVER VALLEY FRI/SAT.
SOME DISAGREEMENTS BETWEEN THE MODELS ON
TIMING/POSITIONING/STRENGTH...WITH THE GFS THE QUICKER OF THE TWO.
OVERALL...BOTH SOLUTIONS POINT TO ANOTHER ROUND OF SHOWERS/STORMS.
WILL SIDE WITH CONSENSUS FOR RAIN CHANCES FOR NOW.
LOOKING AT A SLOW WARM UP THIS WEEK...WITH SOME MID-UPPER 80 DEGREE
READINGS LIKELY BEFORE THE WORK WEEK IS DONE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1139 PM CDT SUN AUG 17 2014
SHOWERS AND STORMS CONTINUE TO REDEVELOP OVER SOUTHEAST MINNESOTA
LATE THIS EVENING IN AN AREA OF WEAK MOISTURE TRANSPORT AND
VERTICAL LIFT AHEAD OF A SHORT WAVE TROUGH COMING ACROSS
MINNESOTA. EXPECT THIS ACTIVITY TO CONTINUE FOR A FEW MORE HOURS
UNTIL THE SHORT WAVE TROUGH MOVES PAST THE AREA AND WILL INITIALLY
HAVE TEMPO GROUPS AND THE VCTS WHEN IT IS SHOULD BE MOVING OUT OF
THE AREA. CONFIDENCE IS HIGHEST THAT KRST WILL CONTINUE TO BE
IMPACTED AS THAT IS WHERE THE NOSE OF THE MOISTURE TRANSPORT IS.
THE RADAR SHOWS THE ACTIVITY WEAKENING AS IT APPROACHES THE
MISSISSIPPI RIVER AND WITH THE MOISTURE TRANSPORT NOT MOVING
MUCH...KLSE MAY NOT SEE A WHOLE LOT OF ACTIVITY SO WILL STAY WITH
VCTS THERE. THE 18.03Z RAP STILL INDICATES THAT LOW STRATUS AND
SOME FOG SHOULD FORM LATE TONIGHT ONCE THE RAIN ENDS...BUT
CONCERNED THAT THE WINDS MAY STAY UP A LITTLE TOO MUCH TO ALLOW
MORE THAN MVFR VISIBILITIES TO DEVELOP. STRATUS EXPECTED TO START
LIFTING LATE MONDAY MORNING WHICH IS WHEN THE NEXT SHORT WAVE
TROUGH WILL BE APPROACHING FROM THE WEST TO START THE NEXT ROUND
OF SHOWERS AND STORMS. FEEL THERE WILL NEED TO BE A PERIOD OF
CATEGORICAL THUNDER FOR BOTH TAF SITES...BUT CONFIDENCE ON WHEN
THIS WILL OCCUR IS TOO LOW TO INCLUDE IT RIGHT NOW. THE 18.00Z NAM
AND 17.12Z HI-RES ARW WOULD SUGGEST LATE AFTERNOON INTO THE
EVENING BUT WHAT IS IN OF THE 18.00Z HI-RES ARW SUGGESTS AS EARLY
AS 18Z MONDAY. WILL CONTINUE WITH VCTS UNTIL THE TRENDS BECOME
CLEARER.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1200 AM MDT MON AUG 18 2014
.UPDATE...
ISSUED AT 905 PM MDT SUN AUG 17 2014
THE EARLIER CRITICAL FIRE WEATHER CONDITIONS HAVE IMPROVED
DRAMATICALLY OVER THE PAST FEW HOURS. SO...IN AN EARLIER
UPDATE LET THE HIGHLIGHT EXPIRE AS SCHEDULED. OTHERWISE...THE
PESKY HIGH-BASED CONVECTION THAT PRODUCED GUSTS OF 55-60 MPH AT A
FEW OBSERVATION SITES EARLIER THIS EVENING...HAVE ALL DISSIPATED
WITH LOSS OF HEATING THIS EVENING. INITIAL LOOKS AT 00Z CONTINUES
TO SUPPORT THE IDEA OF ISOLATED CONVECTION LATE TOMORROW
AFTERNOON...PRIMARILY OVER THE SE WYOMING PLAINS. THE 00Z NAM
TARGETS LARAMIE COUNTY AS HAVING THE BEST CHANCE. WILL SEE WHAT
THE 00Z GFS SUGGESTS BEFORE MAKING ANY CHANGES TO THE FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 330 PM MDT SUN AUG 17 2014
AFTERNOON WATER VAPOR LOOP REVEALED A CLOSED UPPER LOW NORTH OF THE
NORTH DAKOTA BORDER WITH A TROUGH AXIS INTO THE WESTERN DAKOTAS.
CLUSTERS OF INTENSE CONVECTION WERE DEVELOPING AHEAD OF THIS FEATURE.
CYS/RIW RADARS SHOWED A FEW SHOWERS DEVELOPING ALONG A WEAK
CONVERGENCE ZONE FROM SOUTHERN NATRONA TO SOUTHERN CONVERSE COUNTY.
THE HRRR MODEL COMPOSITE REFLECTIVITY LOOP SHOWED THIS ACTIVITY
MOVING ACROSS EAST CENTRAL WYOMING THROUGH LATE AFTERNOON THEN
DISSIPATING. WITH VERY DRY SUB-CLOUD LAYER...CAN EXPECT GUSTY WINDS
AND LITTLE IF ANY MEASURABLE RAINFALL WITH THESE SHOWERS. MAIN
CONCERN CONTINUES TO BE FIRE WEATHER IMPACTS FROM THE GUSTY WINDS
AND LOW HUMIDITY FOR ELEVATIONS BELOW 8000 FT. RED FLAG WARNING
REMAINS IN EFFECT FOR ALL BUT THE SIERRA MADRE/SNOWY RANGE ZONES
THROUGH 7 PM. GETTING CLOSE TO RED FLAG CRITERIA OVER THE NEBRASKA
PANHANDLE ZONES BORDERING WYOMING. CONDITIONS WILL IMPROVE THIS
EVENING AS WINDS DECREASE AND HUMIDITIES INCREASE.
A BLEND OF THE 12Z SHORT RANGE MODEL GUIDANCE HANDLES THE LARGE SCALE
PATTERN PRETTY WELL. THE UPPER TROUGH ADVANCES EAST SOUTHEAST ACROSS
THE DAKOTAS AND MIDWEST DURING THE NEXT 24 HOURS. MEANWHILE...A UPPER
RIDGE EXPANDS NORTHWEST FROM THE FOUR CORNERS REGION WITH A HEALTHY
SURGE OF SUBTROPICAL MOISTURE MOVING INTO THE CENTRAL ROCKIES
TUESDAY. PRECIP WATER VALUES MONDAY WILL RANGE FROM A HALF INCH WEST
OF THE LARAMIE RANGE TO AROUND AN INCH FOR THE HIGH PLAINS.
TUESDAY...PRECIP WATER INCREASE TO AROUND 1.25 INCHES EAST OF THE
LARAMIE AND 0.75-1.0 INCH TO THE WEST. DIURNAL CONVECTIVE COVERAGE
MONDAY WILL BE ISOLATED AND CONFINED TO THE MOUNTAINS. THE AIRMASS
OVER THE PLAINS WILL REMAIN CAPPED PRECLUDING SHOWER DEVELOPMENT.
SHOWER/TSTORM COVERAGE INCREASES TO SCATTERED TUESDAY
AFTERNOON/EVENING AS A POTENT SHORTWAVE RIDES NORTHEAST ACROSS
WYOMING AND COLORADO. DOWNSLOPING WESTERLY WINDS WILL LIMIT QPF OVER
THE EASTERN WYOMING PLAINS...WITH AT LEAST O.25 INCH AMOUNTS
POSSIBLE OVER THE HIGHER TERRAIN AND WESTERN NEBRASKA PANHANDLE.
ABOVE NORMAL WARMTH WILL CONTINUE MONDAY LOWER ELEVATIONS MONDAY AND
EAST OF THE LARAMIE RANGE TUESDAY WITH HIGHS IN THE 80S TO LOWER 90S.
TEMPERATURES WILL TREND SLIGHTLY COOLER WEST OF THE LARAMIE RANGE
TUESDAY DUE TO GREATER CLOUD AND SHOWER COVERAGE.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 300 PM MDT SUN AUG 17 2014
WARM AND MAINLY DRY WEATHER EXPECTED ACROSS THE CWA WEDNESDAY AND
THURSDAY THOUGH A FEW SHOWERS/TSTRMS POSSIBLE OVER THE HIGHER SRN
MTNS BOTH AFTERNOONS/EARLY EVENINGS. CHANGES LOOK TO BE IN THE
OFFING BEGINNING FRIDAY AND CONTINUING INTO THE WEEKEND AS AN
UPPER TROF SETTLES OVER THE NW PART OF THE COUNTRY AND A PUSH OF
COOLER CANADIAN AIR DROPS DOWN THE HIGH PLAINS SATURDAY AND
SATURDAY NIGHT WITH THE EC CONTINUING TO BE MUCH MORE BULLISH IN
PUSHING THIS COOL AIR ACROSS THE CWA BY LATE SATURDAY...SETTING UP
A MILD DAY FOR SUNDAY. EC HAS BEEN CONSISTENT WITH THIS. SHOULD
ALSO SEE A BIT OF AN UPTICK IN CONVECTION FRIDAY AND SATURDAY AS
THE UPPER TROF NEARS WITH ANY ASSOCIATED IMPULSES ROUNDING THE
BASE OF IT PASSING ACROSS THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1159 PM MDT SUN AUG 17 2014
A WEAK COLD FRONT HAS MOVED THROUGH THE MAJORITY OF THE CWA THIS
EVENING...WITH WINDS BEHIND THE FRONT OUT OF THE EAST-NORTHEAST
AND REMAINING LIGHT. WINDS WILL CONTINUE TO BE LIGHT ON MONDAY
WITH THE UPSLOPE COMPONENT HELPING TO SPARK OFF SHOWERS AND
TSTORMS IN THE AFTERNOON. HIGHEST CHANCE FOR STORMS WILL BE NEAR
KCYS AND KLAR AFTER 19Z.
&&
.FIRE WEATHER...
ISSUED AT 703 PM MDT SUN AUG 17 2014
CONDITIONS WILL CONTINUE TO IMPROVE ACROSS THE DISTRICTS THROUGH
THE REST OF THE EVENING. THEREFORE...ALLOWED THE RED FLAG WARNING
TO EXPIRE AT 7 PM.
FIRE WEATHER CONCERNS WILL BECOME MINIMAL MONDAY AND TUESDAY AS AN
INFLUX OF MONSOON MOISTURE FROM THE SOUTHWEST INCREASES CHANCES
FOR WETTING RAINS EARLY THIS WEEK. WINDS WILL BE LIGHTER AS WELL.
DRIER CONDITIONS RETURN MID WEEK FOLLOWED BY A SLIGHT INCREASE IN
MOISTURE LATE IN THE WEEK. ABOVE AVERAGE TEMPERATURES THIS WEEK
WILL GRADUALLY COOL NEXT WEEKEND.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...HAHN
SHORT TERM...JAMSKI
LONG TERM...RE
AVIATION...RJM
FIRE WEATHER...JAMSKI
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
844 AM MST MON AUG 18 2014
.SYNOPSIS...
AN EARLY SEASON PACIFIC LOW PRESSURE SYSTEM WILL APPROACH THE AREA
TODAY...AND WILL DRAW EVEN MORE MONSOON MOISTURE NORTHWARD BACK INTO
ARIZONA. MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS
EXPECTED ACROSS ARIZONA FROM LATE TONIGHT THROUGH MUCH OF THIS WEEK.
WITH THE INCREASE IN HUMIDITIES AND CLOUDS...BELOW NORMAL
TEMPERATURES ARE POSSIBLE BY TUESDAY AND WILL LIKELY CONTINUE
THROUGH THE REMAINDER OF THE WORKWEEK.
&&
.DISCUSSION...
HIGHLY DIFLUENT 300/250 MB WINDS FLOWING ANTI-CYCLONICALLY AROUND A
LARGE OFFSHORE BAJA ANTICYCLONE...WITH A WEAK EMBEDDED SHORTWAVE
PROVIDED SUPPORT FOR PROPAGATING STORMS OVERNIGHT FROM PHOENIX WEST
TO THE COLORADO RIVER. A FEW STORMS STILL REMAINED AT 8 AM MST...BUT
OUTSIDE OUR COUNTY WARNING AREA...CWA...IN SAN BERNARDINO AND MOHAVE
COUNTIES.
CONCERN FOR LATER TODAY THROUGH EARLY TUESDAY IS AN EVEN STRONGER
DIFLUENT/DYNAMIC FLOW ASSOCIATED WITH A SOUTHWARD MOVING EARLY
SEASON TROF ALONG THE WEST COAST. IT LOOKS LIKE A TEMPORARY BREAK IN
POTENTIAL STORM ACTIVITY THROUGH LATE THIS AFTERNOON...THEN THE APEX
OF THE SPREADING DIFLUENT FLOW INCREASES IN THE SOUTHEAST
CA/COLORADO RIVER AREA IN EARNEST BY EVENING. AT THE SAME TIME...
MOISTURE ADVECTION FROM MEXICO INCREASES IN SOUTHWEST AZ IN RESPONSE
TO FALLING ATMOSPHERIC HEIGHTS IN THE MOHAVE DESERT AND IN SOUTHWEST
NEVADA.
THE APEX OF THE DIFLUENT FLOW SHIFTS EAST OVERNIGHT FROM THE
COLORADO RIVER VALLEY INTO THE PHOENIX AREA BY TUESDAY MORNING...
THUS PROVIDING SHWR/TSTM POTENTIAL OVERNIGHT ACROSS MOST OF
SOUTHWEST AND SOUTH CENTRAL AZ. THIS PATTERN IS CERTAINLY A-TYPICAL
AND WARRANTS AN UPGRADE TO PRECIP PROBABILITIES...POPS...CWA WIDE.
UPDATES WERE MADE THIS MORNING TO INCREASE POPS INTO THE CHANCE
CATEGORY ACROSS THE CWA WITHOUT ANY LARGE POP INCONSISTENCIES OR
DISCREPANCIES NEAR ADJACENT OFFICE BOUNDARIES.
OTHERWISE NO OTHER CHANGES ARE EXPECTED THIS MORNING. PREVIOUS
DISCUSSION STILL APPLIES.
.PREVIOUS DISCUSSION...520 AM MST...
TODAY THROUGH WEDNESDAY...
THERE IS NOW EXCELLENT MODEL AGREEMENT ON THE FORECAST FOR OUR CWA
THROUGH WEDNESDAY. BOTH THE GFS AND EURO ARE TRACKING A RATHER
VIGOROUS UPPER LOW CENTER SOUTHWARD ALONG THE CA COAST DURING THIS
PERIOD...WITH INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW AHEAD OF
THIS LOW CENTER PULLING ADDITIONAL MOISTURE NORTHWARD INTO THE
REGION. A REFLECTION OF THIS MOISTURE...A VERY LARGE THUNDERSTORM
COMPLEX CAN BEEN SEEN ON IR AND WATER VAPOR IMAGERY THIS MORNING
OVER EXTREME NORTHWEST SONORA MEXICO...JUST SOUTH OF THE
INTERNATIONAL BORDER. OUTFLOWS FROM THE TS COMPLEX WILL LIKELY PUSH
SFC DEWPOINTS EVEN HIGHER OVER SOUTHWEST AZ THIS MORNING...PROVIDING
THE FUEL FOR TS DEVELOPMENT LATER THIS AFTERNOON. THE LATEST HRRR IS
NOW SHOWING...AFTER A BIT OF A BREAK LATER THIS MORNING AND EARLY
AFTERNOON...WHICH WILL THE ATMOSPHERE A CHANCE TO RELOAD AFTER BEING
WORKED OVER BY LAST NIGHT`S CONVECTIVE ACTIVITY...THUNDERSTORMS
REBUILDING OVER THE HIGHER TERRAIN NORTH AND EAST OF PHX AND OVER SE
AZ...THEN BEGIN TO MOVE THEM INTO THE LOWER ELEVATIONS BY LATE
AFTERNOON AND EARLY EVENING. ONCE AGAIN...THE MAIN IMPACTS FROM
THESE STORMS WILL BE GUSTY WINDS/LOCALIZED BLOWING DUST/BRIEF HEAVY
DOWNPOURS.
SHOWER/TS ACTIVITY WILL LIKELY CONTINUE WELL INTO TONIGHT AND INTO
TUESDAY...ESPECIALLY OVER SOUTH-CENTRAL AND SW AZ AS PWATS RISE INTO
THE 1.80-2.00 INCH RANGE...AND UPPER-LEVEL DIFLUENCE DEVELOPS OVER
THE REGION. HEAVY RAIN/LOCALIZED FLOODING WILL LIKELY BE THE MAIN
ISSUE WITH STORMS LATER TONIGHT AND TUESDAY AS THE VERY MOIST
AIRMASS WILL MAKE THEM MORE EFFICIENT RAINFALL PRODUCERS...WITH
LOCALIZED RAINFALL AMOUNTS AOA 1 INCH LIKELY IN A FEW SPOTS. THE
WIDESPREAD RAINFALL/CLOUDINESS IS EXPECTED TO PUSH HIGH TEMPS ON
TUESDAY BACK BELOW NORMAL...WITH MANY LOWER DESERT LOCATIONS ACROSS
SOUTH-CENTRAL AZ REMAINING BELOW 100F.
A BIT OF A BREAK IS LIKELY ON WEDNESDAY AS THE MAIN MOISTURE PLUME
IS PUSHED TO THE SOUTH AND EAST BY THE APPROACHING UPPER LOW CENTER
AS IT PUSHES INLAND OVER SOUTHERN CA...BUT SCATTERED THUNDERSTORMS
ARE STILL LIKELY TO DEVELOP OVER THE HIGHER TERRAIN NORTH AND EAST
OF PHOENIX.
THURSDAY THROUGH SATURDAY...
SOME MODEL CONSENSUS IS FINALLY BEGINNING TO SHOW UP DURING THIS
PERIOD. THE EURO IS NOW BEGINNING TO SIDE WITH THE GFS...BY TAKING
THE MAIN UPPER LOW CENTER INLAND INTO AZ/NM...WITH CONSIDERABLE
TROPICAL MOISTURE FROM THE REMAINS OF TROPICAL CYCLONE 12E...WHICH
HAS NOW FORMED WELL SOUTHWEST OF THE TIP OF BAJA CALIFORNIA...MOVING
INTO THE DESERT SOUTHWEST AHEAD OF THIS LOW CENTER. THERE IS STILL
CONSIDERABLE TIMING DIFFERENCES BETWEEN THE TWO MODELS...WITH THE
GFS MOVING THE UPPER LOW CENTER INTO AZ LATE THU NIGHT/EARLY
FRIDAY...WHILE THE MUCH SLOWER EURO MOVES IT INTO AZ ON SATURDAY.
EITHER WAY...IT APPEARS MORE-AND-MORE LIKELY THAT A SIGNIFICANT
RAINFALL EVENT COULD DEVELOP OVER AZ...WITH TEMPS FALLING WELL BELOW
NORMAL...WHICH IS VERY UNUSUAL IN MID-LATE AUGUST. THUS...HAVE
RAISED POPS ACROSS THE BOARD DURING THIS PERIOD.
SUNDAY AND MONDAY...
A RETURN TO A MUCH DRIER...AND WARMER PATTERN IS EXPECTED DURING
THIS PERIOD AS BOTH THE GFS AND EURO BEGIN TO DIG A BROAD LONG-WAVE
TROF SOUTHWARD INTO THE INTERMOUNTAIN WEST...WITH WESTERLY FLOW
ALOFT ADVECTING MUCH DRIER AIR INTO THE REGION.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
CONVECTION CONTINUES THIS MORNING ACROSS NORTHERN PORTIONS OF THE
VALLEY...AFFECTING KSDL AND POSSIBLY KPHX. WILL KEEP VCTS IN THE
TAFS THRU 14Z OR SO...MAY HAVE TO UPGRADE TO TEMPO GROUPS FOR
CONVECTION SHOULD STORMS CONTINUE TO DEVELOP. OTHERWISE...INCREASING
MONSOONAL MOISTURE FROM THE SOUTH WILL LEAD TO BETTER CHANCES FOR
STORMS THIS AFTERNOON AND OVERNIGHT TONIGHT. FOR THE MOMENT DUE TO
LACK OF CONFIDENCE IN TIMING AND STRENGTH OF THE STORMS...WILL
SIMPLY PUT VCTS IN THE TAFS AFTER 01Z...TRANSITION TO VCSH AFTER
ABOUT 06Z...WITH BKN MID/UPPER LEVEL CLOUD DEBRIS CLOUD DECKS.
POTENTIAL IS THERE LATER TODAY AND THIS EVENING FOR GUSTY VARIABLE
OUTFLOW WINDS...DENSE BLOWING DUST...RESTRICTED VISIBILITY AS WELL
AS STORMS AT THE TERMINALS. WILL UPDATE TAFS LATER TODAY AS NEEDED.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
STRONG GUSTY EASTERLY OUTFLOW WINDS PERSIST AT KIPL...AND SHOW
LITTLE SIGN OF EASING UP SO WILL KEEP ELY GUSTS TO 32KT WITH VSBYS
TO 4SM AND LOW CIGS AS WELL THRU 14Z. HOPEFULLY THE WINDS WILL HAVE
TAPERED OFF BY THEN. MAY SEE A FEW SHOWERS OR HIGH BASED STORMS IN
THE AREA THRU MID MORNING AFFECTING BOTH KIPL AND BLH...WILL KEEP
VCSH THRU MID/LATE MORNING AND AMEND FOR THUNDER AS NEEDED.
OTHERWISE WINDS SHOULD FAVOR THE SOUTH OR SOUTHEAST NEXT 24 HOURS AT
BOTH TAF SITES. FROM 18Z THRU TUESDAY MORNING...EXPECT MAINLY
MID/UPPER LEVEL SCT-BKN CLOUD DECKS...THREAT FOR SHOWERS/STORMS NOT
HIGH ENOUGH TO MENTION IN THE TAFS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
DEEP MONSOON MOISTURE WILL CONTINUE THIS PERIOD WITH HIGHER THAN
NORMAL RELATIVE HUMIDITY. A GOOD CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS ARE EXPECTED OVER HIGHER MOUNTAINS OF SOUTHERN GILA
COUNTY EACH DAY...WITH A SLIGHT CHANCE OF THUNDERSTORMS ON THE LOWER
SOUTHWEST AND SOUTH CENTRAL DESERTS. MINIMUM RELATIVE HUMIDITIES WILL
RANGE FROM 25 TO 30 PERCENT. OVERNIGHT RECOVERY WILL BE GOOD.
AFTERNOON TEMPERATURES WILL BE BELOW NORMAL THIS PERIOD ESPECIALLY
FROM PHOENIX EASTWARD. ADDITIONALLY...AFTERNOON/EARLY EVENING WINDS
WILL BE SOUTHWESTERLY AND GENERALLY UNDER 20 MPH...EXCEPT NEAR
THUNDERSTORMS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...VASQUEZ/PERCHA
AVIATION...CB
FIRE WEATHER...VASQUEZ/CB
AREA FORECAST DISCUSSION...UPDATED
NWS PHOENIX AZ
520 AM MST MON AUG 18 2014
.UPDATE...UPDATED AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
.SYNOPSIS...
AN EARLY SEASON PACIFIC LOW PRESSURE SYSTEM WILL APPROACH THE AREA
TODAY...AND WILL DRAW EVEN MORE MONSOON MOISTURE NORTHWARD BACK INTO
ARIZONA. MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS
EXPECTED ACROSS ARIZONA FROM LATE TONIGHT THROUGH MUCH OF THIS WEEK.
WITH THE INCREASE IN HUMIDITIES AND CLOUDS...BELOW NORMAL
TEMPERATURES ARE POSSIBLE BY TUESDAY AND WILL LIKELY CONTINUE
THROUGH THE REMAINDER OF THE WORKWEEK.
&&
.DISCUSSION...
TODAY THROUGH WEDNESDAY...
THERE IS NOW EXCELLENT MODEL AGREEMENT ON THE FORECAST FOR OUR CWA
THROUGH WEDNESDAY. BOTH THE GFS AND EURO ARE TRACKING A RATHER
VIGOROUS UPPER LOW CENTER SOUTHWARD ALONG THE CA COAST DURING THIS
PERIOD...WITH INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW AHEAD OF
THIS LOW CENTER PULLING ADDITIONAL MOISTURE NORTHWARD INTO THE
REGION. A REFLECTION OF THIS MOISTURE...A VERY LARGE THUNDERSTORM
COMPLEX CAN BEEN SEEN ON IR AND WATER VAPOR IMAGERY THIS MORNING
OVER EXTREME NORTHWEST SONORA MEXICO...JUST SOUTH OF THE
INTERNATIONAL BORDER. OUTFLOWS FROM THE TS COMPLEX WILL LIKELY PUSH
SFC DEWPOINTS EVEN HIGHER OVER SOUTHWEST AZ THIS MORNING...PROVIDING
THE FUEL FOR TS DEVELOPMENT LATER THIS AFTERNOON. THE LATEST HRRR IS
NOW SHOWING...AFTER A BIT OF A BREAK LATER THIS MORNING AND EARLY
AFTERNOON...WHICH WILL THE ATMOSPHERE A CHANCE TO RELOAD AFTER BEING
WORKED OVER BY LAST NIGHT`S CONVECTIVE ACTIVITY...THUNDERSTORMS
REBUILDING OVER THE HIGHER TERRAIN NORTH AND EAST OF PHX AND OVER SE
AZ...THEN BEGIN TO MOVE THEM INTO THE LOWER ELEVATIONS BY LATE
AFTERNOON AND EARLY EVENING. ONCE AGAIN...THE MAIN IMPACTS FROM
THESE STORMS WILL BE GUSTY WINDS/LOCALIZED BLOWING DUST/BRIEF HEAVY
DOWNPOURS.
SHOWER/TS ACTIVITY WILL LIKELY CONTINUE WELL INTO TONIGHT AND INTO
TUESDAY...ESPECIALLY OVER SOUTH-CENTRAL AND SW AZ AS PWATS RISE INTO
THE 1.80-2.00 INCH RANGE...AND UPPER-LEVEL DIFLUENCE DEVELOPS OVER
THE REGION. HEAVY RAIN/LOCALIZED FLOODING WILL LIKELY BE THE MAIN
ISSUE WITH STORMS LATER TONIGHT AND TUESDAY AS THE VERY MOIST
AIRMASS WILL MAKE THEM MORE EFFICIENT RAINFALL PRODUCERS...WITH
LOCALIZED RAINFALL AMOUNTS AOA 1 INCH LIKELY IN A FEW SPOTS. THE
WIDESPREAD RAINFALL/CLOUDINESS IS EXPECTED TO PUSH HIGH TEMPS ON
TUESDAY BACK BELOW NORMAL...WITH MANY LOWER DESERT LOCATIONS ACROSS
SOUTH-CENTRAL AZ REMAINING BELOW 100F.
A BIT OF A BREAK IS LIKELY ON WEDNESDAY AS THE MAIN MOISTURE PLUME
IS PUSHED TO THE SOUTH AND EAST BY THE APPROACHING UPPER LOW CENTER
AS IT PUSHES INLAND OVER SOUTHERN CA...BUT SCATTERED THUNDERSTORMS
ARE STILL LIKELY TO DEVELOP OVER THE HIGHER TERRAIN NORTH AND EAST
OF PHOENIX.
THURSDAY THROUGH SATURDAY...
SOME MODEL CONSENSUS IS FINALLY BEGINNING TO SHOW UP DURING THIS
PERIOD. THE EURO IS NOW BEGINNING TO SIDE WITH THE GFS...BY TAKING
THE MAIN UPPER LOW CENTER INLAND INTO AZ/NM...WITH CONSIDERABLE
TROPICAL MOISTURE FROM THE REMAINS OF TROPICAL CYCLONE 12E...WHICH
HAS NOW FORMED WELL SOUTHWEST OF THE TIP OF BAJA CALIFORNIA...MOVING
INTO THE DESERT SOUTHWEST AHEAD OF THIS LOW CENTER. THERE IS STILL
CONSIDERABLE TIMING DIFFERENCES BETWEEN THE TWO MODELS...WITH THE
GFS MOVING THE UPPER LOW CENTER INTO AZ LATE THU NIGHT/EARLY
FRIDAY...WHILE THE MUCH SLOWER EURO MOVES IT INTO AZ ON SATURDAY.
EITHER WAY...IT APPEARS MORE-AND-MORE LIKELY THAT A SIGNIFICANT
RAINFALL EVENT COULD DEVELOP OVER AZ...WITH TEMPS FALLING WELL BELOW
NORMAL...WHICH IS VERY UNUSUAL IN MID-LATE AUGUST. THUS...HAVE
RAISED POPS ACROSS THE BOARD DURING THIS PERIOD.
SUNDAY AND MONDAY...
A RETURN TO A MUCH DRIER...AND WARMER PATTERN IS EXPECTED DURING
THIS PERIOD AS BOTH THE GFS AND EURO BEGIN TO DIG A BROAD LONG-WAVE
TROF SOUTHWARD INTO THE INTERMOUNTAIN WEST...WITH WESTERLY FLOW
ALOFT ADVECTING MUCH DRIER AIR INTO THE REGION.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
CONVECTION CONTINUES THIS MORNING ACROSS NORTHERN PORTIONS OF THE
VALLEY...AFFECTING KSDL AND POSSIBLY KPHX. WILL KEEP VCTS IN THE
TAFS THRU 14Z OR SO...MAY HAVE TO UPGRADE TO TEMPO GROUPS FOR
CONVECTION SHOULD STORMS CONTINUE TO DEVELOP. OTHERWISE...INCREASING
MONSOONAL MOISTURE FROM THE SOUTH WILL LEAD TO BETTER CHANCES FOR
STORMS THIS AFTERNOON AND OVERNIGHT TONIGHT. FOR THE MOMENT DUE TO
LACK OF CONFIDENCE IN TIMING AND STRENGTH OF THE STORMS...WILL
SIMPLY PUT VCTS IN THE TAFS AFTER 01Z...TRANSITION TO VCSH AFTER
ABOUT 06Z...WITH BKN MID/UPPER LEVEL CLOUD DEBRIS CLOUD DECKS.
POTENTIAL IS THERE LATER TODAY AND THIS EVENING FOR GUSTY VARIABLE
OUTFLOW WINDS...DENSE BLOWING DUST...RESTRICTED VISIBILITY AS WELL
AS STORMS AT THE TERMINALS. WILL UPDATE TAFS LATER TODAY AS NEEDED.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
STRONG GUSTY EASTERLY OUTFLOW WINDS PERSIST AT KIPL...AND SHOW
LITTLE SIGN OF EASING UP SO WILL KEEP ELY GUSTS TO 32KT WITH VSBYS
TO 4SM AND LOW CIGS AS WELL THRU 14Z. HOPEFULLY THE WINDS WILL HAVE
TAPERED OFF BY THEN. MAY SEE A FEW SHOWERS OR HIGH BASED STORMS IN
THE AREA THRU MID MORNING AFFECTING BOTH KIPL AND BLH...WILL KEEP
VCSH THRU MID/LATE MORNING AND AMEND FOR THUNDER AS NEEDED.
OTHERWISE WINDS SHOULD FAVOR THE SOUTH OR SOUTHEAST NEXT 24 HOURS AT
BOTH TAF SITES. FROM 18Z THRU TUESDAY MORNING...EXPECT MAINLY
MID/UPPER LEVEL SCT-BKN CLOUD DECKS...THREAT FOR SHOWERS/STORMS NOT
HIGH ENOUGH TO MENTION IN THE TAFS.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
DEEP MONSOON MOISTURE WILL CONTINUE THIS PERIOD WITH HIGHER THAN
NORMAL RELATIVE HUMIDITY. A GOOD CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS ARE EXPECTED OVER HIGHER MOUNTAINS OF SOUTHERN GILA
COUNTY EACH DAY...WITH A SLIGHT CHANCE OF THUNDERSTORMS ON THE LOWER
SOUTHWEST AND SOUTH CENTRAL DESERTS. MINIMUM RELATIVE HUMIDITIES WILL
RANGE FROM 25 TO 30 PERCENT. OVERNIGHT RECOVERY WILL BE GOOD.
AFTERNOON TEMPERATURES WILL BE BELOW NORMAL THIS PERIOD ESPECIALLY
FROM PHOENIX EASTWARD. ADDITIONALLY...AFTERNOON/EARLY EVENING WINDS
WILL BE SOUTHWESTERLY AND GENERALLY UNDER 20 MPH...EXCEPT NEAR
THUNDERSTORMS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA
AVIATION...CB
FIRE WEATHER...VASQUEZ/CB
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
913 AM EDT MON AUG 18 2014
.SYNOPSIS...
A FRONTAL BOUNDARY WILL STALL OVER VIRGINIA TODAY. A WAVE OF LOW
PRESSURE WILL TRACK EASTWARD ALONG THE STALLED BOUNDARY TONIGHT
BEFORE MOVING OFFSHORE TUESDAY. THE FRONTAL BOUNDARY SHOULD REMAIN
NEARLY STATIONARY FROM THE GREAT LAKES TO THE SOUTHERN MID-ATLANTIC
STATES WEDNESDAY AND THURSDAY WHILE A SERIES OF DISTURBANCES RIDE
ALONG IT. THE FRONT WILL GRADUALLY SHIFT FARTHER SOUTH AND WEST OF
THE AREA FRIDAY AND THIS WEEKEND AS HIGH PRESSURE WEDGES DOWN FROM
EASTERN CANADA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST WATER VAPOR AND 11-3.9 IR SHOW THE QUASI-STATIONARY FRONTAL
BOUNDARY TO OUR SOUTH EXTENDING NORTHEAST INTO THE MARYLAND/WEST
VIRGINIA PANHANDLE. DRY AIR WILL CONTINUE TO PRESS INTO THE REGION
FROM THE NORTH THROUGH THE MORNING HOURS UNDER A LIGHT NORTHERLY
FLOW. WINDS ARE EXPECTED TO VEER TOWARDS THE WEST-SOUTHWEST LATER
THIS AFTERNOON AS THE FRONT WAVERS TO OUR SOUTH. A WEAK SURFACE LOW,
CURRENTLY ACROSS THE MID-WEST, WILL RIDE ALONG THIS FRONTAL BOUNDARY
LATER THIS AFTERNOON..STAYING TO THE SOUTH OF OUR CWA. RAIN WILL
BEGIN TO OVERSPREAD THE EXTREME SOUTHERN DELMARVA ZONES BY LATE THIS
AFTERNOON AND THEY DON`T LOOK TO GET NORTH OF DOVER TODAY. BASED
ON THE LATEST RAP AND HRRR WITH THE 9:30 AM UPDATE, PUSHED BACK
ANY RAIN CHANCE TILL AFTER 20Z. GREATER INSTABILITY AND LOW- LEVEL
MOISTURE CONVERGENCE, AS PWATS SWELL TOWARDS 1.75 INCHES, COULD
ALLOW FOR SCATTERED THUNDERSTORMS AND MODERATE RAINFALL.
ELSEWHERE, THE LOWER PWAT AIR IN PLACE WILL TAKE A WHILE TO MODIFY
SO WE EXPECT A DRY DAY WITH SOME INCREASING CLOUD COVER LATE IN THE
DAY. TEMPERATURES WILL RUN CLOSE TO NORMAL TODAY, LIKE THE PAST FEW
DAYS. DID RAISE TEMPERATURES SLIGHTLY ACROSS THE NORTH WITH THE
9:30 AM UPDATE AS WELL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
THE SURFACE WAVE ALONG THE FRONTAL BOUNDARY WILL PASS TO OUR SOUTH
LATE TONIGHT. THIS SYSTEM OVER THE PAST SEVERAL DAYS HAS TRENDED
TOWARDS A MORE SUPPRESSED, FASTER WEST-EAST MOVEMENT, AND A
SOUTHEASTERN TRACK THAT WOULD ALLOW FOR LESS SIGNIFICANT RAINFALL
THREAT THEN PREVIOUSLY THOUGHT...WE REMOVED THE MENTION FROM THE HWO
AT THIS TIME.
SURFACE FLOW BEGINS TO VEER TOWARDS THE EAST-SOUTHEAST BY THIS
EVENING BRINGING MORE LOW-LEVEL INTO THE REGION...EVERYWHERE. NOT
EXPECTING MUCH IN THE WAY OF RAIN CHANCES LATE TONIGHT, OUTSIDE OF
THE DELMARVA, WITHOUT MUCH SYNOPTIC SCALE LIFT AND DON`T THINK THE
SURFACE FLOW IS STRONG ENOUGH FOR UPGLIDE ACROSS OUR WESTERN ZONES,
SO WE STAY MOSTLY DRY TONIGHT. TEMPERATURES, UNDER INCREASINGLY
CLOUDY SKIES, WILL BE SEVERAL DEGREES WARMER THAN THE PAST FEW
MORNINGS...BLEND OF THE MET/MAV LOOKS GOOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
WHILE OPPRESSIVE HEAT WILL BUILD ACROSS THE SOUTHERN CONUS IN
ASSOCIATION WITH A STRENGTHENING ANTICYCLONE THIS WEEK, IT IS NOT
EXPECTED TO REACH OUR AREA THROUGH THE NEXT 7 DAYS AS THE REGION
WILL GENERALLY BE UNDER THE PRESENCE OF MEAN TROUGHING AND ONSHORE
FLOW AT THE SFC. TEMPS THRU THE PERIOD SHOULD BE NEAR TO SLIGHTLY
BELOW NORMAL FOR THIS TIME OF YEAR.
LOPRES IS EXPECTED TO MOVE OFF THE SOUTHEAST VA COAST TUESDAY
MORNING. MODELS CONTINUE THE TREND TOWARD A WEAKER, MORE PROGRESSIVE
SYSTEM, WHICH WILL RESULT IN A EARLIER END TO THE SHOWERS ACROSS THE
DELMARVA DURING THE MORNING. THERE MAY ALSO BE AN ISOLATED SHOWER
THAT DEVELOPS ACROSS THE HIGHER ELEVATIONS OF PA LATE IN THE DAY,
BUT THE BULK OF DIURNAL CONVECTION SHOULD BE CENTERED CLOSER TO THE
SHARPENING LLVL THETA-E RIDGE, WHICH WILL RESIDE WEST OF THE AREA.
OTHERWISE, DRY CONDITIONS PREVAIL. FCST MAX TEMPS RANGING FROM THE
MID 70S IN THE POCONOS TO MID 80S ALONG THE I-95 CORRIDOR ARE CLOSE
TO CLIMO.
A WEAK RIDGE OF HIPRES BECOMES ESTABLISHED ACROSS THE COASTAL MID
ATLANTIC TUESDAY NIGHT AND WEDNESDAY MORNING. ALTHOUGH MODEL
GUIDANCE HASN`T JUMPED ON IT YET, WILL HAVE TO WATCH FOR THE
POTENTIAL FOR FOG OR STRATUS DEVELOPMENT AS PERSISTENT ONSHORE FLOW
IN THE BOUNDARY LAYER DRAWS MARINE AIR INLAND.
THE NEXT SYSTEM TO IMPACT THE AREA WILL BE A WAVE OF LOPRES OVER THE
GREAT LAKES THAT MOVES SOUTHEASTWARD ALONG THE STALLED FRONTAL
BOUNDARY IN THE MID-ATLANTIC STATES WEDNESDAY AFTERNOON THROUGH
THURSDAY. THE DISTURBANCE IS ALSO FORECAST TO WEAKEN AS THE UPPER
LOW BECOMES AN OPEN WAVE BY THE TIME IT REACHES OUR AREA. THIS LOW
OF PAC NW ORIGIN IS NOT EXPECTED TO TAP INTO APPRECIABLE GULF OF
MEXICO MOISTURE DURING ITS CROSS-COUNTRY TREK. ACCORDINGLY, THE SETUP
DOES NOT PARTICULARLY SUPPORT A HEAVY RAINFALL EVENT OR A WASHOUT,
BUT THERE IS STILL A CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE
SECOND HALF OF THE WORK WEEK. CHANCE POPS INITIALLY CONFINED TO WEST
OF I-95 WEDNESDAY AFTERNOON, BEFORE THIS ACTIVITY WOULD TRY TO
ADVANCE EASTWARD INTO THE REST OF THE CWA WEDNESDAY NIGHT. POPS
THURSDAY HIGHEST CLOSER TO THE STATIONARY BOUNDARY OVER THE
DELMARVA/NORTHEAST MD/SOUTHEAST PA.
A RIDGE OF HIPRES OVER EASTERN CANADA IS EXPECTED TO NOSE DOWN INTO
THE FORECAST AREA FRIDAY THROUGH THE WEEKEND. MODELS NOW SHOW THE
HIGH BECOMING ESTABLISHED ALONG THE EASTERN SEABOARD SOONER THAN
PREVIOUS GUIDANCE HAD INDICATED. TRENDED TOWARD A DRIER FORECAST
FRIDAY INTO THE WEEKEND AS THE HIGH SHOULD ACT TO SHIFT THE OLD
FRONTAL BOUNDARY AND STORM TRACK SOUTH AND WEST OF THE AREA. ONSHORE
FLOW WOULD POSITION THE REGION IN COOLER, MORE STABLE AIRMASS
REGIME.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR. LIGHT AND VARIABLE WINDS THROUGH THE FIRST HALF OF THE
DAY BEFORE A SOUTHWEST FLOW ESTABLISHES ITSELF...LESS THAN 10 KNOTS.
SEA BREEZES POSSIBLE AT ACY AND MIV LATER THIS AFTERNOON.
TONIGHT...VFR. LIGHT AND VARIABLE WINDS. LOW-LEVEL MOISTURE BEGINS
TO CREEP BACK INTO THE REGION WITH A THICKENING STRATOCU DECK
POSSIBLE.
OUTLOOK...
TUESDAY...PRECIP EXITS SRN TERMINALS EARLY IN THE DAY AS LOW
PRESSURE MOVES OFF THE VA COAST. VFR CONDITIONS.
TUESDAY NIGHT THROUGH WEDNESDAY MORNING...STRATUS OR FOG POSSIBLE AS
ONSHORE FLOW DEVELOPS. BEST SETUP WOULD BE CLOSER TO THE COAST
(ACY/MIV).
WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...CHANCE FOR SHRA/TSRA AS
A SERIES OF DISTURBANCES MOVE THRU THE REGION. LOCAL/TEMPORARY
FLIGHT RESTRICTIONS POSSIBLE.
FRIDAY...VFR CONDITIONS.
&&
.MARINE...
WE CONTINUE THE TRANQUIL SUB-SCA CONDITIONS TODAY AND TONIGHT. LIGHT
NORTHERLY WINDS WILL BACK TOWARDS THE SOUTH-SOUTHEAST DURING THE
COURSE OF THE DAY, AND REMAIN BELOW 10 KNOTS. SEAS WILL CONTINUE TO
RUN AROUND 2 TO 3 FEET. WINDS THEN VEER TOWARDS THE EAST LATE
TONIGHT AS A WEAK SURFACE LOW PRESSURE SLIDES EASTWARD TO OUR
SOUTH.
OUTLOOK...
TUESDAY...LOPRES MOVES OFF THE VA COAST. A TIGHT PRESSURE GRADIENT
TO THE NORTH OF THE LOW MAY PRODUCE EASTERLY WINDS 15-20 KT. SCA
POTENTIAL LOW.
WEDNESDAY THROUGH THURSDAY...ONSHORE FLOW CONTINUES BUT WILL WEAKEN
OVER TIME. TSRA POSSIBLE IN SOUTHERN WATERS ON THURSDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLEIN
NEAR TERM...GAINES/HEAVENER
SHORT TERM...HEAVENER
LONG TERM...KLEIN
AVIATION...HEAVENER/KLEIN
MARINE...HEAVENER/KLEIN
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
936 AM EDT MON AUG 18 2014
.DISCUSSION...
TODAY...A BIT OF THE TASTE OF THE LAZY...HAZY DAYS OF SUMMER. EARLY
MORNING ENHANCED VISIBLE SATELLITE IMAGERY SHOWED THE NORTHERN EDGE
OF AN ELEVATED HAZE LAYER (SAHARAN AIR) WAS LIKELY AFFECTING OUR FAR
SOUTHERN SECTIONS AROUND LAKE OKEECHOBEE.
SUBTROPICAL RIDGE AXIS CONTINUES OVER THE SOUTHERN PENINSULA.
HENCE...CENTRAL FLORIDA SOUNDINGS CONTINUED TO SHOW THE ANOMALOUS
DEEP LAYER WESTERLY FLOW WE HAVE HAD FOR MUCH OF THE WET SEASON.
PRECIPITABLE WATER IS AROUND 1.7 INCHES BUT 700 MB TEMPS 9-10 DEGREES
CELSIUS AND SOME DRIER AIR JUST ABOVE THE SURFACE WILL LIMIT STORM
CHANCES ALONG THE SEA BREEZE BOUNDARIES. THE HIGHEST CHANCE FOR
STORMS WILL BE WITH THE EAST/WEST COLLISION LATE IN THE DAY. THE
LOCAL WRF AND HRRR SHOW THE SOUTHERN SEA BREEZE GETTING ACTIVE ABOUT
2-3 PM BUT THIS IS QUESTIONABLE DUE TO THE PARAMETERS NOTED ABOVE.
THEREFORE WILL CONFINE CHANCE POPS TO THE INLAND SOUTH.
WITH THE REDUCED COVERAGE OF SHOWERS/STORMS...IT WILL FEEL HOTTER...
LONGER. HEAT INDICES IN THE LOWER ONE HUNDREDS ARE NOT THAT MUCH
OUT OF THE NORM FOR AUGUST. VALUES MAY CREEP UP TO AROUND 105 IN A
FEW INTERIOR LOCATIONS...BUT THIS IS STILL BELOW HEAT ADVISORY
CRITERIA. THE MAIN THING THOUGH IS THAT THERE WILL BE LIMITED RAIN
COOLING.
&&
.AVIATION...
MAINLY VFR. THE CHANCE FOR STORMS IS TOO LOW TO INCLUDE IN THE
TAFS. THE HIGHEST CHANCE FOR STORMS SHOULD BE AT COASTAL TERMINALS
BUT EXPECT THIS WILL BE LATE IN THE DAY AS THE EAST/WEST SEA BREEZE
BOUNDARIES INTERACT.
&&
.MARINE...
TODAY...CONTINUED GOOD BOATING CONDITIONS WITH OFFSHORE FLOW 10
KNOTS OR LESS. SHOULD GET A SEA BREEZE PUSHING TO INTERIOR SECTIONS
OF THE COASTAL COUNTIES...SOUTH OF CANAVERAL. THE CHANCE FOR
OFFSHORE MOVING STORMS IS LOW AND WILL BE LATE IN THE DAY.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...LASCODY
IMPACT WX...MOSES
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
529 AM CDT MON AUG 18 2014
.AVIATION...
CLUSTER OF INTENSE TSTMS SLOWLY SHIFTING EAST ACROSS SW AR...MOVG
EAST OF KTXK TERMINAL...BUT NOW MOVG INTO KELD TERMINAL. STEEP
LAPSE RATES KEEPING MOST CLOUD BASES IN VFR...EVEN NEAR STORMS.
OUTFLOW BOUNDARIES MAY REGENERATE MIDDAY STORMS OVER KMLU AND
POSSIBLY KSHV TERMINALS...LESS CONVECTIVE ACTIVITY OVER NE TX EXPECTED.
HOWEVER...MID LVL DECKS WITH LGT RAIN MOVG EAST TOWARDS KTYR AND
KGGG. SW WINDS NEAR 10 KTS ACROSS MUCH OF AREA...MAINLY BTWN 18/15-21Z
TODAY...EXCEPT POSSIBLE GUSTS NEAR CONVECTION. ALSO...PATCHY FOG
POSSIBLE OVERNIGHT...MAINLY WHERE HEAVY RAIN FELL AT KTXK AND
KELD./VII/.
&&
.PREV DISCUSSION... /ISSUED 443 AM CDT MON AUG 18 2014/
DISCUSSION...
CONVECTION OVER SW AR HAS RAPIDLY DEVELOPED ON THE ERN PERIPHERY
OF AN MCV...WHERE RADAR AND SATELLITE INDICATE TO BE CENTERED NEAR
DEQ AS OF 09Z. LOCALLY HEAVY RAINFALL HAS BEEN EVIDENT PER
REFLECTIVITY IMAGERY...WHERE PERSISTENT TRAINING OF CONVECTION HAS
RESULTED IN WIDESPREAD 2-4 INCH RAINFALL TOTALS...PER DUAL POL
ESTIMATES. THE 00Z WRF HAS AGAIN INITIALIZED WELL THIS
MORNING WITH THE POSITION AND SLOWER MOVEMENT OF THE MCV...WITH THE
GFS CONTINUING TO SUFFER FROM FEEDBACK PROBLEMS AND SHOWS A MUCH
MORE RAPID PROGRESSION OF THE MCV ACROSS SW AR /EXITING THE AREA SHORTLY
AFTER 12Z/. MEANWHILE...THE LATEST HRRR IS OUT TO LUNCH AND DOES
NOT EVEN ACKNOWLEDGE THE CURRENT CONVECTION BUT DOES SUGGEST SCT
DEVELOPMENT LATER THIS MORNING CONTINUING THROUGH THE AFTERNOON
NEAR THE PARENT UPPER SHEAR AXIS OVER EXTREME NRN LA. THE CURRENT
HEAVY RAINFALL AXIS LINES UP WELL WITH A TONGUE OF GREATER SFC
THETA-E AND SBCAPES...WHICH RANGE FROM 1000-1500 J/KG AS OF 09Z.
THIS SHOULD CONTINUE TO FAVOR A SHORT TERM HEAVY RAINFALL THREAT
THIS MORNING OVER SW AR...AS THE MCV DRIFTS SLOWLY E THIS MORNING.
HAVE SEEN SCT CONVECTION DEVELOP FARTHER S ACROSS NRN
CADDO/BOSSIER/WEBSTER PARISHES AS WELL BENEATH THE MCV WHERE
850-700MB THETA-E RIDGING SHOULD RESULT IN CONVECTION EXPANDING E
ALONG/N OF THE I-20 CORRIDOR THROUGH MIDDAY. GIVEN THESE
OBSERVATIONS AND THE FACT THAT PW/S SHOULD RANGE FROM 2-2.25
INCHES...HAVE INCREASED POPS TO LIKELY THIS MORNING AND ADDED
HEAVY RAINFALL WORDING ACROSS MUCH OF SW AR...AND HAVE MAINTAINED
MID TO HIGH CHANCE POPS FARTHER S ACROSS NCNTRL LA AS THE MCV
SHIFTS E TO THE MS RIVER BY MIDDAY...AND ITS ATTENDANT SHEAR AXIS
DRIFTS ESE ACROSS THE AREA. THE AFTERNOON SEABREEZE SHOULD BE LESS
OF A FACTOR THIS AFTERNOON OVER DEEP E TX AS 850MB WINDS REMAIN
WSW BENEATH THE SHEAR AXIS...THUS SLIGHT CHANCE POPS SHOULD
SUFFICE FOR THESE AREAS. MAX TEMPS TODAY WILL AGAIN BE A TOUGH
CALL...BUT HAVE LOWERED TEMPS SLIGHTLY TO NEAR 90S OVER SCNTRL
AR/NCNTRL LA...WITH MID 90S EXPECTED ELSEWHERE AS THE AC CANOPY
BENEATH THE MCV GRADUALLY ERODES AND GIVES WAY TO SUNSHINE THIS
AFTERNOON.
THE WRF DOES SUGGEST A WEAK REFLECTION OF THE SHEAR AXIS REMAINING
IN PLACE ACROSS N LA/DEEP E TX THIS EVENING...AND THUS HAVE
MAINTAINED SLIGHT CHANCE POPS FOR THESE AREAS. AFTERWARDS...FLAT
500MB RIDGING IS EXPECTED TO SHIFT E INTO THE SRN PLAINS TUESDAY
FROM THE SRN ROCKIES...WITH A WEAK SEABREEZE POSSIBLE ACROSS DEEP
E TX/SRN SECTIONS OF NCNTRL LA DURING THE AFTERNOON AND EARLY
EVENING. UPPER RIDGING OVER THE WRN ATLANTIC AND ERN GULF REMAINS
PROGGED TO EXPAND FARTHER WNW WHILE ABSORBING THE 500MB RIDGE
CENTER OVER THE LOWER MS VALLEY WEDNESDAY...BEFORE CENTERING
ITSELF OVER THE MID-SOUTH REGION/LOWER MS VALLEY THURSDAY. STILL
SHOULD SEE A COUPLE MORE DAYS OF WEAK SEABREEZE CONVECTION ACROSS
OUR SRN ZONES WEDNESDAY AND THURSDAY...BEFORE LARGE SCALE
SUBSIDENCE BENEATH THE RIDGE INCREASES AS THE RIDGE CENTER BECOMES
POSITIONED OVER THE REGION.
PERSISTENCE WILL DOMINATE LATE THIS WEEK THROUGH THE REMAINDER OF
THE EXTENDED...WITH MAX TEMPS IN THE MID/UPPER 90S EACH DAY. STILL
CAN/T RULE OUT TRIPLE DIGIT HEAT OCCURRING LATE THIS WEEK THROUGH
EARLY NEXT WEEKEND ESPECIALLY OVER E TX/PORTIONS OF NW LA...WHICH
HAVE BEEN MOSTLY VOID OF WETTING RAINFALL THE LAST FEW WEEKS AND
WILL APPEAR TO MISS MUCH OF THE CONVECTION THIS MORNING. BOTH THE
GFS/ECMWF DO SUGGEST THAT THE RIDGE CENTER MAY SHIFT A TAD FARTHER
E INTO THE SE STATES BY MIDWEEK NEXT WEEK...ALLOWING WEAKNESSES
BENEATH THE RIDGE TO RETROGRADE W AND POSSIBLY ALLOW FOR ISOLATED
CONVECTION OVER THE SRN ZONES AS WE ENTER THE FINAL FEW DAYS OF
AUGUST.
PRELIMS TO FOLLOW BELOW...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 94 75 96 75 96 / 30 10 10 10 10
MLU 90 74 95 74 95 / 50 20 10 10 10
DEQ 93 71 95 72 95 / 30 10 10 0 0
TXK 93 74 95 74 96 / 40 10 10 0 0
ELD 91 73 95 73 96 / 60 10 10 0 0
TYR 95 75 96 75 96 / 30 10 10 10 10
GGG 94 74 96 74 96 / 30 10 10 10 10
LFK 96 76 97 76 96 / 20 20 20 10 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1055 AM EDT MON AUG 18 2014
.SYNOPSIS...
HIGH PRESSURE WILL KEEP OUR WEATHER QUIET THROUGH EARLY TUESDAY.
AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS CAN THEN BE
EXPECTED LATE TUESDAY INTO ESPECIALLY WEDNESDAY AND THURSDAY...AS
A LOW PRESSURE SYSTEM MOVES THROUGH THE GREAT LAKES REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
1045 AM UPDATE...
BASED ON LATEST VISIBLE SATELLITE LOOP SHOWING AN EXTENSIVE AREA
OF STRATOCU FORMING OVER A LARGE SECTION OF OUR AREA, I INCREASED
SKY COVER THROUGH 18Z. AFTER THAT TIME RUC SOUNDINGS SHOW RAPID
INCREASING AMOUNTS OF DRY AIR UNDERNEATH THE SUBSIDENCE
INVERSION. WITH THAT IN MIND WE SHOULD SEE A SUBSTANTIAL INCREASE
IN SUNSHINE THIS AFTERNOON, WITH A MOSTLY SUNNY SKY BY 21Z. WE CAN
SEE THIS HAPPENING ALREADY OVER NORTHERN NY. ASIDE FROM THE SKY
CHANGE, OUR TEMPS ARE ON TRACK.
645 AM UPDATE... BROAD SURFACE HIGH PRESSURE WILL SHIFT
FROM CENTRAL ONTARIO INTO WESTERN QUEBEC-NORTHERN NEW YORK TODAY
THROUGH TONIGHT. INTERESTINGLY ENOUGH...UNDER THE CENTER OF THE
HIGH...TIMMINS ONTARIO WAS DOWN TO 37 DEGREES AS OF 6 AM...AND
ROUYN-NORANDA IN EXTREME WESTERN QUEBEC WAS DOWN TO 34 DEGREES.
WHILE THE CENTER OF THE HIGH WILL PASS TO OUR NORTH...IT WILL
STILL DOMINATE THE WEATHER IN CENTRAL NEW YORK TO NORTHEAST
PENNSYLVANIA...KEEPING THINGS PRETTY QUIET IN THE NEAR TERM. AND
AS HINTED AT ABOVE...A CHILLY NIGHT TONIGHT ESPECIALLY MOHAWK
VALLEY-WESTERN CATSKILLS.
A VERY WEAK WAVE DROPPED THROUGH THE STILL BRISK NORTHWEST FLOW
ALOFT OVERNIGHT...ALLOWING SOME CLOUDS AND EVEN A COUPLE SPRINKLES
TO SETTLE ACROSS CENTRAL NEW YORK DURING THE PREDAWN HOURS.
HOWEVER...THE CLOUDS HAVE TENDED TO SCATTER OUT WHILE EDGING SOUTHWARD
ACROSS THE TWIN TIERS. THUS...PATCHY DENSE FOG AND/OR LOW STRATUS
HAS FORMED ESPECIALLY IN THE VALLEYS OF THE TWIN TIERS AS WELL AS
NORWICH AND SIDNEY. ALSO SOME LOW STRATUS HANGING OVER ITHACA. THOSE
CLOUDS FOR SOME AND VALLEY FOG FOR OTHERS WILL DISSIPATE THE NEXT
FEW HOURS...LEADING TO A MOSTLY SUNNY AND PLEASANT DAY WITH
TEMPERATURES A SHADE BELOW CLIMATOLOGICAL AVERAGES.
FOR TONIGHT...A WEAK SYSTEM BOUND FOR THE MIDATLANTIC COAST WILL
BE WELL SOUTH OF US...YET CLOSE ENOUGH FOR SOME INCREASE IN CLOUDS
TOWARDS DAWN FROM CENTRAL TWIN TIERS TO NEPA. HOWEVER...NY THRUWAY
CORRIDOR TO WESTERN CATSKILLS SHOULD REMAIN CLEAR ALL NIGHT. WHILE
NOT AS COLD AS THAT READING MENTIONED ABOVE IN EXTREME WESTERN
QUEBEC...STRONG RADIATIONAL COOLING WILL MANAGE TO SEND TEMPERATURES
INTO THE LOW TO MID 40S IN THE TYPICALLY COLDER SPOTS OF UPPER
SUSQUEHANNA-MOHAWK VALLEY-WESTERN CATSKILL VALLEYS FOR LOWS.
QUITE CHILLY FOR MID AUGUST. FARTHER SOUTH AND WEST...WHERE CLOUDS
WILL INCREASE LATE...LOWS WILL STILL BE ON THE COOL SIDE IN THE
UPPER 40S TO LOW 50S...EXCEPT FOR MID 50S TOWARDS WYOMING VALLEY
OF PA.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
345 AM UPDATE...
A TROUGH WILL DIG INTO THE UPPER MIDWEST AND CUT OFF AN UPPER LOW
ON TUESDAY...WITH A WEAK SURFACE LOW FORMING OVER EAST-CENTRAL
WISCONSIN AS A RESULT. WELL AHEAD OF THE LOW...WARM AIR ADVECTION
IN OUR REGION WILL ALLOW TEMPERATURES AND DEWPOINTS TO CREEP UP
ENOUGH FOR SOME MARGINAL INSTABILITY TUESDAY AFTERNOON...THOUGH
BETTER IN WESTERN PORTIONS OF NY-PA. I HAVE INCLUDED SLIGHT TO LOW
CHANCE OF SHOWERS AND THUNDERSTORMS /NOT STRONG/...FOCUSED MAINLY
WEST OF A TOWANDA-ITHACA-AUBURN LINE. MOST OF OUR AREA WILL BE DRY
TUESDAY...WITH NEAR NORMAL TEMPERATURES...AND EVEN A DECENT AMOUNT
OF SUNSHINE AT LEAST IN CENTRAL NY.
SOUTHWEST FLOW ALOFT TUESDAY NIGHT...AHEAD OF APPROACHING UPPER
LOW...WILL BRING MORE MOISTURE INTO THE COLUMN. EMBEDDED WEAK
WAVES WITHIN THE FLOW MAY REALIZE SOME SHOWERS...THOUGH WITH NO
DIURNAL HEATING...THEY SHOULD BE LIMITED IN COVERAGE. CLOUDS
THOUGH WILL DEFINITELY BE INCREASING.
WEDNESDAY-WEDNESDAY NIGHT...AREAWIDE CHANCES FOR SHOWERS WILL GO
UP MARKEDLY. BOTH UPPER LOW AND SURFACE LOW /AND ITS OCCLUDING
FRONT/ WILL ADVANCE ACROSS CENTRAL GREAT LAKES WEDNESDAY...THEN
ENTERING OUR REGION WEDNESDAY NIGHT. HOWEVER...SURFACE HIGH
PRESSURE RIDGE WILL BE HOLDING STRONG ACROSS NEW ENGLAND...AND
SOUTHEAST-TO-SOUTH LOW LEVEL FLOW FROM IT MAY HAVE STABILIZING
INFLUENCE ON AT LEAST OUR EASTERN ZONES. SO WHILE SHOWERS ARE A
GOOD BET...THUNDER CHANCES MAY BE A BIT MUTED EAST OF HIGHWAY 81.
FARTHER WEST...MARGINAL INSTABILITY WILL HAVE A LITTLE BETTER
CHANCE OF BEING REALIZED AS EMBEDDED THUNDER WITHIN THE SHOWERS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
305 AM UPDATE...
DIFFUSE LONG WAVE TROF WILL REMAIN FIXED OVER EASTERN CANADA THIS
PERIOD, EXTENDING SOUTHWESTWARD THROUGH NY AND PA. THIS WILL KEEP
OUR WEATHER UNSETTLED THROUGH THE WORK WEEK, WITH A CHANCE FOR A
SHOWER OR THUNDERSTORM EACH DAY.
THE HIGHEST POTENTIAL DAY FOR CONVECTION APPEARS TO BE THURSDAY,
WHEN A WEAK SURFACE WAVE RIDES OUT OF THE OHIO VALLEY. MID LEVEL
LAPSE RATES WILL INCREASE TO 6 TO 6.5 PER THE LATEST ECMWF
PROG...LOW END MARGINAL FOR DECENT CONVECTION BUT UNSTABLE ENOUGH
TO SUGGEST AN INCREASED THREAT FOR PRECIPITATION.
PREV DISCUSSION...
TROFFINESS CONTS AT THE BEGINNING OF THE LONG TERM. 12Z GFS IS
TRYING TO DVLP A REX BLOCK OVR THE NORTHEAST BY MID- WEEK. HV
UNDERCUT WPC GUIDANCE SLIGHTLY WITH HICHC POPS EXPECTED ON WED
NGT. PATTERN STILL LOOKS TO BE UP IN THE AIR AND NOT CONFIDENT
ENUF TO GO LKLY THIS FAR OUT.
CHC POPS CONTINUE EACH PD WITH UPR LOW SPINNING IN THE GULF OF MAINE
THRU THE END OF THE LONG TERM WITH 590 RIDGE BUILDING INTO THE
MIDWEST LVG CWA IN NW FLOW PATTERN. THIS PATTERN WL LKLY THROW
SUBTLE S/WVS AT RANDOM INTO THE NE U.S. IN CONTRAST, 12Z CMC KEEPS
AREA IN ZONAL FLOW DUE TO H5 RIDGE AXIS BEING SUPPRESSED DOWN ALONG
THE GULF COAST.
SFC HIPRES BUILDS IN FM CANADIAN MARITIMES AND SHUNTS CHC POPS TO
THE EAST BUT NOT COMPLETELY OUT OF THE AREA ON SATURDAY. SFC RIDGE
AXIS BUILDS EVEN FURTHER TO THE WEST SAT NGT ACCOMPANIED BY BUILDING
H5 RIDGE WHICH MAY LEAD TO A DRY PD DRG THE LATTER HALF OF THE
WEEKEND.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
635 AM UPDATE...
THE FOCUS CONTINUES TO BE ON DENSE FOG FORMATION OUTSIDE OF THE
LAKE STRATUS CLOUD COVER. ELM IS DEEP INTO IFR TERRITORY THIS
MORNING, WHILE BGM HAS BEEN FLIRTING WITH IFR VISIBILITY AS THE
MISTS ROLL UP THE HILLSIDE TOWARD THE TERMINAL.
EXPECT IFR CONDITIONS AT LEAST ON A TEMPO BASIS AT BGM AND ELM
THROUGH ABOUT 1330-1400Z.
ANOTHER ROUND OF DENSE FOG IS LIKELY TUESDAY MORNING. IFR
CONDITIONS ARE FORECAST AT ELM.
PREVIOUS DISCUSSION...
A COMPLICATED SCENARIO THIS MORNING. LAKE CLOUDS OFF ONTARIO WILL
PRODUCE AN OVERCAST STRATUS DECK. THIS DECK WILL GRADUALLY LOWER
INTO MVFR TERRITORY AS THE LOWER ATMOSPHERIC MOISTURE PROFILE THICKENS.
OUTSIDE OF THE LAKE CLOUDS, CLEARING SKIES WILL ALLOW TEMPERATURES
TO FALL WELL BELOW THE CROSSOVER TEMPS FROM THE PREVIOUS
AFTERNOON. WITH LIGHT WINDS IN PLACE, THIS APPEARS TO BE A GREAT
SCENARIO FOR DENSE FOG.
CURRENTLY ELM IS FORECAST TO DESCEND INTO IFR FOG BY AROUND 8Z.
THE PROBLEM IS THAT THE LAKE CLOUD STRATUS IS JUST NORTH OF ELM,
AND COULD COMPLETELY CHANGE THE SCENARIO TO MVFR IF THE WIND
SHIFTS THE CLOUDS BACK OVER THE TERMINAL.
CLOUDS SHOULD BURN OFF BY LATE MORNING. VFR CONDITIONS AND LIGHT
WINDS ARE FORECAST TODAY.
OUTLOOK...
MON NGT...EARLY MORNING RIVER VALLEY FOG AT ELM.
TUE-WED MORN...VFR.
WED AFTN-FRI...MVFR RESTRICTIONS POSSIBLE IN SHRA/TSRA DURING THE
AFTERNOON.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...HEDEN/MDP
SHORT TERM...MDP
LONG TERM...DJP/PVN
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
637 AM CDT MON AUG 18 2014
.UPDATE...
12Z TAF DISCUSSION.
&&
.AVIATION...
SCT -SHRA CONTINUE TO DEVELOP ACROSS THE MID STATE ALTHOUGH MAINLY
SOUTH OF AREA AIRPORTS...SO WILL MENTION VCSH AT BNA/CSV THROUGH
18Z IN LINE WITH LATEST HRRR MODEL. VFR CIGS EXPECTED AT BNA/CSV
TODAY...WHILE CURRENT IFR CIGS/VIS AT CKV WILL IMPROVE TO VFR BY
LATE MORNING. LIGHT SOUTHWEST TO WEST WINDS ARE ANTICIPATED
THROUGH THE TAF PERIOD.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 456 AM CDT MON AUG 18 2014/
DISCUSSION...
SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE LAST COUPLE OF HOURS
SOUTH OF I-40. SOUTHERN MAURY AND MARSHALL COUNTIES APPEAR TO BE
EXPERIENCING THE HEAVIEST RAINFALL THIS MORNING...WITH RADAR
ESTIMATING AROUND 1 TO 2 INCHES AND MORE RAIN ON THE WAY. SHOWERS
APPEAR TO BE BACK BUILDING AND TRAINING OVER THE SAME
AREAS...FURTHER INCREASING THE THREAT FOR FLASH FLOODING FOR
SOUTHERN MIDDLE TENNESSEE. PWATS REMAIN AROUND 2 INCHES WITH
UNIDIRECTIONAL FLOW THROUGHOUT THE MORNING. THE BULK OF THIS
ACTIVITY WILL PUSH EAST THROUGHOUT THE MORNING...BUT MORE SHOWERS
WITH HEAVY DOWNPOURS WILL BE POSSIBLE THROUGHOUT THE DAY.
TUESDAY`S THUNDERSTORM ACTIVITY LOOKS TO BE MORE WIDELY
SCATTERED...WITH THE BEST CHANCE OVER THE CUMBERLAND PLATEAU
DURING THE EVENING HOURS. WEDNESDAY AND THURSDAY CONDITIONS BEGIN
TO DRY OUT AS HIGH PRESSURE BUILDS OVER THE LOWER MS VALLEY. WILL
STILL CARRY A SLIGHT CHANCE OF SHOWERS AND STORMS OVER THE PLATEAU
THROUGH THE END OF THE FORECAST PERIOD AS EAST TENNESSEE REMAINS
UNDER NORTHWEST FLOW AND IS INFLUENCED BY AN AREA OF LOW PRESSURE
MOVING ACROSS THE NORTHEAST U.S.
THE MAIN STORY AFTER TODAY WILL BE OUR WARMING TREND WITH THE HIGH
PRESSURE BUILDING JUST TO OUR SOUTHWEST...TEMPERATURES ARE
EXPECTED TO SOAR INTO THE MID TO UPPER 90S AFTER TUESDAY.
APPARENT TEMPS COULD BE AROUND 100 DEGREES FOR THE LATTER HALF OF
THE WORK WEEK. WARM TEMPS AND DRY WEATHER WILL CONTINUE INTO NEXT
WEEKEND.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
627 AM CDT MON AUG 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT MON AUG 18 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED TROUGHING FROM LAKE WINNIPEG INTO THE DAKOTAS AND RIDGING
OVER MICHIGAN. BETWEEN THESE TWO FEATURES...THERE WERE SHORTWAVES
NEAR LA CROSSE AND IN SOUTHEAST SOUTH DAKOTA. DPVA FROM THE FORMER
SHORTWAVE...COMBINED WITH A ZONE OF 850MB MOISTURE TRANSPORT WHICH
EXTENDED FROM NORTH CENTRAL IA INTO NORTH CENTRAL WI...HAS RESULTED
IN SCATTERED TO NUMEROUS CONVECTION OVER THE NORTHWEST HALF OF THE
FORECAST AREA. PRECIPITABLE WATER VALUES FROM THE RAP SHOW VALUES OF
1.5-1.8 INCHES IN GENERAL...HIGHEST WITHIN THE CONVECTION. THESE
HIGH VALUES HAS ALLOWED CONVECTION TO HAVE HEAVY RAINFALL RATES...
WITH UPWARDS OF 2 INCHES PER HOUR FROM THE ONE THAT WENT THROUGH THE
ROCHESTER AREA LATE LAST EVENING. TO THE WEST...ANOTHER ZONE OF 1.5-
1.8 INCH PRECIPITABLE WATER WAS PRESENT OVER FAR WESTERN MN...AHEAD
OF THE DAKOTAS UPPER TROUGH AND SOUTHEAST SOUTH DAKOTA SHORTWAVE.
DPVA FROM THESE FEATURES ACTING ON THE MOISTURE RESULTING IN
ISOLATED SHOWER AND STORM ACTIVITY IN FAR WESTERN MN TOO.
THE UPPER TROUGH FROM LAKE WINNIPEG INTO THE DAKOTAS REMAINS ON
TRACK TO MOVE INTO THE FORECAST AREA TONIGHT. PRETTY MUCH ALL DAY
TODAY THROUGH THE EVENING HOURS THE FORECAST AREA IS UNDER FALLING
500MB HEIGHTS. COMBINE THIS WITH A SERIES OF SHORTWAVES COMING
THROUGH FROM THE TROUGH SUCH AS THAT ONE IN SOUTHEAST SOUTH
DAKOTA...THE 1.5-1.8 INCH PRECIPITABLE WATER AIRMASS IN PLACE...AND
DAYTIME HEATING TO ADD EVEN MORE INSTABILITY...RESULTS IN A VERY
FAVORABLE SETUP FOR CONVECTION. THE MAJORITY OF THE FORECAST AREA
SHOULD SEE RAIN OVER THE NEXT 18 HOURS...WITH CORRIDORS OF HEAVIER
RAIN POSSIBLE DUE TO THE HIGH PRECIPITABLE WATER VALUES.
SPECIFICALLY TIMING THE WET AND DRY PERIODS IS VERY PROBLEMATIC...
BUT IN GENERAL IT SEEMS AS IF THERE COULD BE A DRY PERIOD AROUND MID-
MORNING. THIS WOULD CORRELATE WITH THE WEAKENING OF THE LOW LEVEL
JET AND A PERIOD OF SUBSIDENCE BETWEEN THE DEPARTING LA CROSSE
SHORTWAVE AND THE OTHER SHORTWAVE COMING IN FROM THE SIOUX FALLS.
WELL SEE. THE AFTERNOON INTO THE EARLY EVENING HOURS CERTAINLY BODE
WELL FOR CONVECTION WITH THE DAYTIME INSTABILITY HELP...THUS HIGHEST
CHANCES ARE CENTERED THEN. EVEN DURING THIS TIME FRAME...THERE COULD
BE 2-3 HOUR BREAKS BETWEEN ROUNDS OF CONVECTION. ANOTHER SPECIFIC
NOTE...IT WOULD APPEAR THE SOUTHEAST END OF THE FORECAST AREA MAY
NOT GET HIT WITH MUCH CONVECTION UNTIL LATE AFTERNOON OR THE EVENING
HOURS.
LOOK FOR THE CONVECTION TO PUSH OFF TO THE EAST LATE THIS
EVENING THROUGH THE OVERNIGHT HOURS...DUE TO A COMBINATION OF
SUBSIDENCE WORKING IN FROM THE WEST WITH THE TROUGH MOVING IN
PLACE...AS WELL AS LOSS OF DAYTIME HEATING DIMINISHING INSTABILITY.
A COLD FRONTAL PASSAGE LOOKS TO OCCUR AS WELL TONIGHT TO AID IN THE
DIMINISHING TREND.
REGARDING SEVERE WEATHER POTENTIAL...LOOKING AT SHEAR...WE MAY
NEED TO WATCH THE LATE AFTERNOON AND EVENING HOURS. AT 00Z...THE 0-
3KM SHEAR CLIMBS TO 25 KT AROUND I-90 AND 30-35 KT IN NORTHEAST
IOWA. IF CONVECTION EXISTS INTO THESE REGIONS...THEY MAY HAVE
SOME SEVERE WIND POTENTIAL. OTHERWISE...WARM CLOUD DEPTHS UPWARDS OF
3000-3500 METERS WILL RESULT IN HEAVY RAIN AS THE MAIN CONCERN. HAVE
NOT ISSUED ANY FLASH FLOOD WATCH GIVEN ANTECEDENT DRY
CONDITIONS...HOWEVER...LOCALIZED FLOOD ADVISORIES OR WARNINGS MAY
BE NEEDED...ESPECIALLY IN URBAN AREAS WHICH CANNOT HANDLE
HIGHER RAINFALL RATES.
THE CONVECTION AROUND TODAY MAKES FOR A TRICKY HIGH TEMPERATURE
FORECAST. 925MB TEMPS CLIMBING TO 19-22C ON AN INCREASING SOUTHWEST
WIND COULD ALLOW FOR HIGHS OF 80-85 UNDER THE FULL SUN.
HOWEVER...HAVE TO HOLD THESE BACK AS MUCH AS 5 DEGREES OR SO TO
ACCOUNT FOR CONVECTION. WARMEST READINGS ARE LIKELY IN THE SOUTHEAST
END WITH THE LONGEST DRY PERIOD EXPECTED. LOWS TONIGHT EXPECTED ON
THE MILD SIDE AGAIN WITH THE COLD FRONTAL PASSAGE MAKING THE BIGGER
IMPACT TO LOWERING TEMPERATURES.
WITH THE PRECIPITATION ENDING DURING THE NIGHT TIME HOURS...FOG
POTENTIAL NEEDS TO BE CONSIDERED. HOWEVER...IT APPEARS THERE SHOULD
BE A DECENT WEST TO NORTHWEST BREEZE IN THE WAKE OF THE COLD FRONTAL
PASSAGE TO KEEP THE AIR MIXED...PREVENTING FOG FORMATION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 324 AM CDT MON AUG 18 2014
TUESDAY INTO TUESDAY NIGHT...MODELS TAKE THEIR SWEET TIME IN GETTING
THE UPPER TROUGH OUT OF THE REGION. HOWEVER...IT DOES LOOK TO GET A
DECENT PUSH EAST LATE TUESDAY NIGHT...RESPONDING TO UPPER RIDGING
BEING FORCED TO BUILD UP OVER THE DAKOTAS INTO MN. WHATS
INTERESTING DURING THIS TIME PERIOD IS SUGGESTIONS OF A SECONDARY
COLD FRONT DROPPING SOUTH THROUGH THE AREA DURING THE AFTERNOON AND
EVENING...CONNECTED WITH ANOTHER SHORTWAVE COMING THROUGH THE
TROUGH. HAVE MAINTAINED SOME PRECIPITATION CHANCES...HIGHEST OVER
NORTH CENTRAL WISCONSIN UNDER THE COOLER AIR ALOFT AND HIGHEST
PRECIPITABLE WATER. MUCH OF THE PRECIPITATION SHOULD END BY LATE
EVENING WITH LOSS OF DAYTIME HEATING AND UPPER TROUGH BEGINNING TO
PULL AWAY. IT SHOULD BE NOTED THE RAINFALL RATES ON TUESDAY DO NOT
LOOK NEARLY AS HIGH TODAY...A RESULT OF THE PRECIPITABLE WATER
VALUES ONLY IN THE 1-1.5 RANGE. LATE TUESDAY NIGHT...WE SHOULD GET A
SURFACE RIDGE OF HIGH PRESSURE TO BUILD INTO THE WESTERN 2/3 OF THE
REGION. SKIES SHOULD CLEAR AND WINDS WILL RELAX WITH THE RIDGE
COMING IN...SETTING UP CONDITIONS FAVORABLE FOR SOME FOG TO FORM.
DETAILS ON THE EXPANSE AND THICKNESS OF THE FOG WILL DEPEND EXACTLY
ON THE TIMING OF THE RIDGE COMING IN. DESPITE THE COLD FRONTAL
PASSAGE...925MB TEMPS ARE PROGGED PRETTY SIMILAR ON TUESDAY TO
TODAY. THE SOUTHERN FORECAST AREA SHOULD BE WARMEST GIVEN BETTER
MIXING POTENTIAL.
FOR WEDNESDAY INTO THURSDAY...MODELS BRING THAT UPPER RIDGING OVER
MN INTO THE FORECAST AREA. IT WOULD APPEAR ENOUGH SUBSIDENCE SHOULD
BE IN PLACE PRIOR TO THE RIDGE BUILDING IN TO YIELD A DRY DAY
WEDNESDAY. ADDITIONALLY...THE MAIN WARM FRONTAL BOUNDARY LOOKS TO BE
WELL TO THE SOUTH...ONLY NEAR THE MISSOURI/IOWA BORDER AT 00Z
THURSDAY. HOWEVER...THIS BOUNDARY LOOKS TO SURGE NORTHWARD TOWARDS
THE FORECAST AREA WEDNESDAY NIGHT...AND POSSIBLY COMPLETELY THROUGH
ON THURSDAY. A DECENT PUSH OF 850MB MOISTURE TRANSPORT INTO THE
BOUNDARY WILL INITIATE ELEVATED CONVECTION OVER THE SOUTHWEST
2/3 OF THE AREA. AGAIN HEAVY RAIN LOOKS TO BE A BIG CONCERN AS
PRECIPITABLE WATER CLIMBS BACK UP TOWARDS 2 INCHES...ALONG WITH A
FEED OF INSTABILITY INTO THE CONVECTION FROM THE LOW LEVEL JET...AND
POTENTIAL TO BE IN THE RIGHT ENTRANCE REGION OF A JET STREAK OVER
LOWER MICHIGAN. RIGHT NOW IT APPEARS THE BOUNDARY SHOULD CONTINUE TO
LIFT NORTHWARD...HELPING TO PREVENT A WIDER FLASH FLOOD THREAT...BUT
NEEDS TO BE WATCHED CLOSELY. ADDITIONALLY...CANNOT RULE OUT SOME
SEVERE WIND POTENTIAL FROM THE CONVECTION. CONVECTION SHOULD
DIMINISH LATE THURSDAY MORNING THROUGH THE AFTERNOON HOURS WITH THE
WEAKENING OF THE LOW LEVEL JET...AND AS CAPPING COMES IN ALOFT.
TEMPERATURES AFTER HOVERING IN THE MID 70S TO LOW 80S THROUGH
WEDNESDAY COULD MAKE A MAJOR BOOST ON THURSDAY. THERE IS POTENTIAL
ACCORDING TO THE 18.00Z ECMWF FOR LOCATIONS ALONG/WEST OF THE MS
RIVER TO GET CLOSE TO 90...ALL DEPENDING ON SUN AND WARM FRONTAL
BOUNDARY TRACK.
FOR THURSDAY NIGHT THROUGH THE WEEKEND...THE 500MB PATTERN FEATURES
UPPER RIDGING TO BEGIN THE PERIOD OVER THE AREA WHILE TROUGHING
EXISTS ACROSS THE PACIFIC NORTHWEST. MODELS ARE IN BETTER AGREEMENT
TODAY THAN YESTERDAY HANDLING THIS TROUGH...AND IT APPEARS SOME
OF THIS TROUGH WILL PUSH EAST INTO THE WEEKEND AND HELP SHIFT THE
RIDGE EASTWARD. THIS TRANSLATES INTO A STORM SYSTEM TO AFFECT THE
REGION FOR FRIDAY THROUGH THE WEEKEND. THE ASSOCIATED WARM FRONT
LOOKS TO LIFT INTO THE REGION ON FRIDAY...WHICH MAY OR MAY NOT
CONVECT DEPENDING ON CAPPING. A COLD FRONTAL PASSAGE COULD OCCUR ON
SATURDAY...FOLLOWED BY A LOW RIDING UP ALONG THE FRONT ON SUNDAY.
CONVECTION IS EASILY POSSIBLE ON BOTH OF THESE FEATURES.
THEREFORE...CHANCES OF SHOWERS AND THUNDERSTORMS LITTER MUCH OF THE
EXTENDED. PRIOR TO THE COLD FRONTAL PASSAGE...925MB TEMPS LOOK TO
RANGE FROM 22-26C...SUPPORTIVE OF 80S TO POSSIBLY 90...DEPENDING ON
AMOUNT OF SUN. AIRMASS APPEARS HUMID TOO. COOLER AIR THEN FILTERS
IN FOR SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 627 AM CDT MON AUG 18 2014
PERIODS OF SHOWERS AND THUNDERSTORMS ARE EXPECTED AT THE TAF SITES
FROM LATE THIS MORNING INTO THE AFTERNOON HOURS. IFR CONDITIONS
ARE POSSIBLE IN THE HEAVIER ACTIVITY THIS AFTERNOON. HAVE TRIED TO
TIME THE PERIODS OF HIGHEST CONFIDENCE FOR THE THUNDERSTORM
ACTIVITY AT THE TAF SITES BUT GIVEN THE UNSTABLE AIRMASS OVER THE
REGION AND THE BROAD FORCING MOVING IN...THE THUNDERSTORMS WILL
LIKELY BECOME WIDESPREAD AND TIMING THE STORMS THROUGH THE TAF
SITES WILL BE CHALLENGING ESPECIALLY LATE THIS AFTERNOON INTO THIS
EVENING. CONDITIONS SHOULD GRADUALLY IMPROVE TO VFR LATE THIS
EVENING INTO THE OVERNIGHT HOURS. FORECAST GUIDANCE IS HINTING AT
SOME FOG TONIGHT BUT LOOKING AT THE FORECAST SOUNDINGS...THE
WEST/NORTHWEST FLOW JUST ABOVE THE SURFACE SHOULD PROMOTE ENOUGH
MIXING TO LIMIT FOG DEVELOPMENT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1246 PM CDT MON AUG 18 2014
.AVIATION...
A STATIONARY FRONT REMAINS ACROSS NORTH ARKANSAS TODAY.
THUNDERSTORMS HAVE EXITIED SOUTHEAST ARKANSAS AND HAVE DEVELOPED
IN NORTHEAST OKLAHOMA. THE STORMS IN NORTHEAST OKLAHOMA SHOULD
MISS THE TAF SITES. ISOLATED THUNDERSTORMS COULD DEVELOP THIS
AFTERNOON HOWEVER. SOME LOW CLOUDS WILL LINGER IN CENTRAL AND
SOUTH SECTIONS FOR A COUPLE OF HOURS. BROKEN CUMULUS ARE EXPECTED
FOR THE REST OF THE AFTERNOON. PATCHY FOG IS LIKELY IN THE MORNING
ESPECIALLY IN CENTRAL AND SOUTH SECTIONS. AFTER SOME IFR
CONDITIONS EARLY THIS AFTERNOON...EXPECT VFR TO MVFR THE REST OF
THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1109 AM CDT MON AUG 18 2014/
UPDATE...
CONVECTION STARTING TO CLEAR OUT IN THE SE PART OF THE CWA AND
HAS LEFT A POOL OF RAIN COOLED TEMPERATURES IN ITS WAKE. MAKING
ADJUSTMENTS TO MAX TEMPERATURES TODAY BASED ON THIS...AND ALSO
MAKING TWEAKS TO POPS...DEW POINTS...AND CLOUD COVER BASED ON
CURRENT SYNOPTIC SITUATION.
HRR AND RUC MODELS FORECASTING REDEVELOPMENT OF CONVECTION THIS
AFTERNOON ACROSS PORTIONS OF NORTH CENTRAL AND CENTRAL ARKANSAS. 53
PREV DISCUSSION... /ISSUED 647 AM CDT MON AUG 18 2014/
AVIATION...18/12Z TAF CYCLE
AREA OF SHRA/TSRA...ASSOCD WITH AN MCV...WL CONT TO TRACK EWD ACRS
CNTRL AND SRN AR THIS MRNG. WIDESPREAD MVFR/IFR CONDS CAN BE
EXPECTED WITH THIS ACTIVITY. CANNOT RULE OUT SOME WDLY SCTD
CONVECTION ACRS THE AREA THIS AFTN. OTHERWISE...VFR CONDS WL
PREVAIL. THERE IS THE POTENTIAL THAT A COMPLEX OF STORMS COULD
ORGANIZE ACRS MO LATE TNGT...EVENTUALLY AFFECTING PARTS OF NRN AR
TUE MRNG. IF THIS DOES OCCUR...NRN FCST SITES WOULD NOT BE IMPACTED
UNTIL AFT THIS FCST PD. /44/
PREV DISCUSSION... /ISSUED 357 AM CDT MON AUG 18 2014/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
A STALLED BOUNDARY REMAINS STRETCHED ACROSS NORTHERN AR EARLY THIS
MORNING...WITH ISOLATED AREAS OF CONVECTION ON GOING DURING THE
OVERNIGHT HOURS. THIS FEATURE WILL BRING AT LEAST SOME CHANCE OF
STORMS TO NORTHERN AND CENTRAL AREAS TODAY...ESPECIALLY AS
DIURNAL HEATING OCCURS.
MEANWHILE...AN UPPER LEVEL LOW IS SWINGING OUT OF THE
ARKLATEX REGION...SPARKING A COMPLEX OF SHOWERS AND THUNDERSTORMS.
THIS AREA OF STORMS WILL SHIFT EASTWARD ACROSS SOUTHERN ARKANSAS
THROUGH THE MORNING HOURS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE
GIVEN ITS INITIAL SLOW MOVING NATURE. PRECIPITATION CHANCES WILL
CONTINUE ACROSS SOUTHERN AREAS THROUGH THE DAY BEFORE THE SYSTEM
EXITS EAST.
THE AFOREMENTIONED STALL FRONTAL BOUNDARY WILL BEGIN TO LIFT BACK
TO THE NORTH LATE THIS EVENING INTO TUESDAY AS HIGH PRESSURE
BEGINS TO BUILD BACK INTO THE REGION. STILL HAVE PRECIP CHANCES
ACROSS NORTHERN AND EASTERN LOCATIONS THROUGH MID WEEK AS AN
UPPER LEVEL SYSTEM INTERACTS WITH THE BOUNDARY JUST NORTH OF THE
STATE. OTHERWISE...THE MAJORITY OF THE STATE WILL REMAIN DRY.
HOT SUMMERTIME TEMPERATURE WILL RETURN IN FULL FORCE UNDER THE DOME OF
HIGH PRESSURE.
LONG TERM...FRIDAY THROUGH SUNDAY
HIGH PRES ALOFT IS PROGGED TO BE SITUATED ACRS THE REGION LATE THIS
WEEK AND INTO THE WEEKEND. THIS WL RESULT IN TYPICAL SUMMERTIME
CONDS WITH HIGHS IN THE 90S AND LOW TEMPS IN THE UPR 60S TO MID 70S.
AFTN HEAT INDICES ARE FCST TO RANGE FROM 100 TO 104 DEGREES EACH
AFTN. EXPECT LTL IN THE WAY OF DIURNAL CONVECTION TO PROVIDE ANY
RELIEF FM THE HEAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 74 96 75 98 / 20 20 20 10
CAMDEN AR 75 96 74 96 / 20 10 10 10
HARRISON AR 72 95 71 95 / 20 20 10 10
HOT SPRINGS AR 75 95 74 95 / 20 10 10 10
LITTLE ROCK AR 75 96 75 97 / 20 10 10 10
MONTICELLO AR 74 94 74 96 / 20 10 10 10
MOUNT IDA AR 73 94 73 95 / 20 10 10 10
MOUNTAIN HOME AR 73 96 72 97 / 20 20 20 10
NEWPORT AR 73 95 72 97 / 20 20 20 10
PINE BLUFF AR 73 95 74 96 / 20 10 10 10
RUSSELLVILLE AR 73 97 73 97 / 20 10 10 10
SEARCY AR 72 95 73 96 / 20 20 10 10
STUTTGART AR 72 94 72 95 / 20 20 10 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...51
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1109 AM CDT MON AUG 18 2014
.UPDATE...
CONVECTION STARTING TO CLEAR OUT IN THE SE PART OF THE CWA AND
HAS LEFT A POOL OF RAIN COOLED TEMPERATURES IN ITS WAKE. MAKING
ADJUSTMENTS TO MAX TEMPERATURES TODAY BASED ON THIS...AND ALSO
MAKING TWEAKS TO POPS...DEW POINTS...AND CLOUD COVER BASED ON
CURRENT SYNOPTIC SITUATION.
HRR AND RUC MODELS FORECASTING REDEVELOPMENT OF CONVECTION THIS
AFTERNOON ACROSS PORTIONS OF NORTH CENTRAL AND CENTRAL ARKANSAS. 53
&&
.PREV DISCUSSION... /ISSUED 647 AM CDT MON AUG 18 2014/
AVIATION...18/12Z TAF CYCLE
AREA OF SHRA/TSRA...ASSOCD WITH AN MCV...WL CONT TO TRACK EWD ACRS
CNTRL AND SRN AR THIS MRNG. WIDESPREAD MVFR/IFR CONDS CAN BE
EXPECTED WITH THIS ACTIVITY. CANNOT RULE OUT SOME WDLY SCTD
CONVECTION ACRS THE AREA THIS AFTN. OTHERWISE...VFR CONDS WL
PREVAIL. THERE IS THE POTENTIAL THAT A COMPLEX OF STORMS COULD
ORGANIZE ACRS MO LATE TNGT...EVENTUALLY AFFECTING PARTS OF NRN AR
TUE MRNG. IF THIS DOES OCCUR...NRN FCST SITES WOULD NOT BE IMPACTED
UNTIL AFT THIS FCST PD. /44/
PREV DISCUSSION... /ISSUED 357 AM CDT MON AUG 18 2014/
SHORT TERM...TODAY THROUGH THURSDAY NIGHT
A STALLED BOUNDARY REMAINS STRETCHED ACROSS NORTHERN AR EARLY THIS
MORNING...WITH ISOLATED AREAS OF CONVECTION ON GOING DURING THE
OVERNIGHT HOURS. THIS FEATURE WILL BRING AT LEAST SOME CHANCE OF
STORMS TO NORTHERN AND CENTRAL AREAS TODAY...ESPECIALLY AS
DIURNAL HEATING OCCURS.
MEANWHILE...AN UPPER LEVEL LOW IS SWINGING OUT OF THE
ARKLATEX REGION...SPARKING A COMPLEX OF SHOWERS AND THUNDERSTORMS.
THIS AREA OF STORMS WILL SHIFT EASTWARD ACROSS SOUTHERN ARKANSAS
THROUGH THE MORNING HOURS. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE
GIVEN ITS INITIAL SLOW MOVING NATURE. PRECIPITATION CHANCES WILL
CONTINUE ACROSS SOUTHERN AREAS THROUGH THE DAY BEFORE THE SYSTEM
EXITS EAST.
THE AFOREMENTIONED STALL FRONTAL BOUNDARY WILL BEGIN TO LIFT BACK
TO THE NORTH LATE THIS EVENING INTO TUESDAY AS HIGH PRESSURE
BEGINS TO BUILD BACK INTO THE REGION. STILL HAVE PRECIP CHANCES
ACROSS NORTHERN AND EASTERN LOCATIONS THROUGH MID WEEK AS AN
UPPER LEVEL SYSTEM INTERACTS WITH THE BOUNDARY JUST NORTH OF THE
STATE. OTHERWISE...THE MAJORITY OF THE STATE WILL REMAIN DRY.
HOT SUMMERTIME TEMPERATURE WILL RETURN IN FULL FORCE UNDER THE DOME OF
HIGH PRESSURE.
LONG TERM...FRIDAY THROUGH SUNDAY
HIGH PRES ALOFT IS PROGGED TO BE SITUATED ACRS THE REGION LATE THIS
WEEK AND INTO THE WEEKEND. THIS WL RESULT IN TYPICAL SUMMERTIME
CONDS WITH HIGHS IN THE 90S AND LOW TEMPS IN THE UPR 60S TO MID 70S.
AFTN HEAT INDICES ARE FCST TO RANGE FROM 100 TO 104 DEGREES EACH
AFTN. EXPECT LTL IN THE WAY OF DIURNAL CONVECTION TO PROVIDE ANY
RELIEF FM THE HEAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 93 74 96 75 / 30 20 20 20
CAMDEN AR 89 75 96 74 / 50 20 10 10
HARRISON AR 93 72 95 71 / 20 20 20 10
HOT SPRINGS AR 90 75 95 74 / 40 20 10 10
LITTLE ROCK AR 89 75 96 75 / 40 20 10 10
MONTICELLO AR 87 74 94 74 / 60 20 10 10
MOUNT IDA AR 92 73 94 73 / 30 20 10 10
MOUNTAIN HOME AR 93 73 96 72 / 20 20 20 20
NEWPORT AR 91 73 95 72 / 40 20 20 20
PINE BLUFF AR 86 73 95 74 / 50 20 10 10
RUSSELLVILLE AR 94 73 97 73 / 30 20 10 10
SEARCY AR 90 72 95 73 / 40 20 20 10
STUTTGART AR 87 72 94 72 / 50 20 20 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1050 AM MST MON AUG 18 2014
.UPDATE...AVIATION DISCUSSION UPDATED...
&&
.SYNOPSIS...
AN EARLY SEASON PACIFIC LOW PRESSURE SYSTEM WILL APPROACH THE AREA
TODAY...AND WILL DRAW EVEN MORE MONSOON MOISTURE NORTHWARD BACK INTO
ARIZONA. MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS
EXPECTED ACROSS ARIZONA FROM LATE TONIGHT THROUGH MUCH OF THIS WEEK.
WITH THE INCREASE IN HUMIDITIES AND CLOUDS...BELOW NORMAL
TEMPERATURES ARE POSSIBLE BY TUESDAY AND WILL LIKELY CONTINUE
THROUGH THE REMAINDER OF THE WORKWEEK.
&&
.DISCUSSION...
HIGHLY DIFLUENT 300/250 MB WINDS FLOWING ANTI-CYCLONICALLY AROUND A
LARGE OFFSHORE BAJA ANTICYCLONE...WITH A WEAK EMBEDDED SHORTWAVE
PROVIDED SUPPORT FOR PROPAGATING STORMS OVERNIGHT FROM PHOENIX WEST
TO THE COLORADO RIVER. A FEW STORMS STILL REMAINED AT 8 AM MST...BUT
OUTSIDE OUR COUNTY WARNING AREA...CWA...IN SAN BERNARDINO AND MOHAVE
COUNTIES.
CONCERN FOR LATER TODAY THROUGH EARLY TUESDAY IS AN EVEN STRONGER
DIFLUENT/DYNAMIC FLOW ASSOCIATED WITH A SOUTHWARD MOVING EARLY
SEASON TROF ALONG THE WEST COAST. IT LOOKS LIKE A TEMPORARY BREAK IN
POTENTIAL STORM ACTIVITY THROUGH LATE THIS AFTERNOON...THEN THE APEX
OF THE SPREADING DIFLUENT FLOW INCREASES IN THE SOUTHEAST
CA/COLORADO RIVER AREA IN EARNEST BY EVENING. AT THE SAME TIME...
MOISTURE ADVECTION FROM MEXICO INCREASES IN SOUTHWEST AZ IN RESPONSE
TO FALLING ATMOSPHERIC HEIGHTS IN THE MOHAVE DESERT AND IN SOUTHWEST
NEVADA.
THE APEX OF THE DIFLUENT FLOW SHIFTS EAST OVERNIGHT FROM THE
COLORADO RIVER VALLEY INTO THE PHOENIX AREA BY TUESDAY MORNING...
THUS PROVIDING SHWR/TSTM POTENTIAL OVERNIGHT ACROSS MOST OF
SOUTHWEST AND SOUTH CENTRAL AZ. THIS PATTERN IS CERTAINLY A-TYPICAL
AND WARRANTS AN UPGRADE TO PRECIP PROBABILITIES...POPS...CWA WIDE.
UPDATES WERE MADE THIS MORNING TO INCREASE POPS INTO THE CHANCE
CATEGORY ACROSS THE CWA WITHOUT ANY LARGE POP INCONSISTENCIES OR
DISCREPANCIES NEAR ADJACENT OFFICE BOUNDARIES.
OTHERWISE NO OTHER CHANGES ARE EXPECTED THIS MORNING. PREVIOUS
DISCUSSION STILL APPLIES.
.PREVIOUS DISCUSSION...520 AM MST...
TODAY THROUGH WEDNESDAY...
THERE IS NOW EXCELLENT MODEL AGREEMENT ON THE FORECAST FOR OUR CWA
THROUGH WEDNESDAY. BOTH THE GFS AND EURO ARE TRACKING A RATHER
VIGOROUS UPPER LOW CENTER SOUTHWARD ALONG THE CA COAST DURING THIS
PERIOD...WITH INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW AHEAD OF
THIS LOW CENTER PULLING ADDITIONAL MOISTURE NORTHWARD INTO THE
REGION. A REFLECTION OF THIS MOISTURE...A VERY LARGE THUNDERSTORM
COMPLEX CAN BEEN SEEN ON IR AND WATER VAPOR IMAGERY THIS MORNING
OVER EXTREME NORTHWEST SONORA MEXICO...JUST SOUTH OF THE
INTERNATIONAL BORDER. OUTFLOWS FROM THE TS COMPLEX WILL LIKELY PUSH
SFC DEWPOINTS EVEN HIGHER OVER SOUTHWEST AZ THIS MORNING...PROVIDING
THE FUEL FOR TS DEVELOPMENT LATER THIS AFTERNOON. THE LATEST HRRR IS
NOW SHOWING...AFTER A BIT OF A BREAK LATER THIS MORNING AND EARLY
AFTERNOON...WHICH WILL THE ATMOSPHERE A CHANCE TO RELOAD AFTER BEING
WORKED OVER BY LAST NIGHT`S CONVECTIVE ACTIVITY...THUNDERSTORMS
REBUILDING OVER THE HIGHER TERRAIN NORTH AND EAST OF PHX AND OVER SE
AZ...THEN BEGIN TO MOVE THEM INTO THE LOWER ELEVATIONS BY LATE
AFTERNOON AND EARLY EVENING. ONCE AGAIN...THE MAIN IMPACTS FROM
THESE STORMS WILL BE GUSTY WINDS/LOCALIZED BLOWING DUST/BRIEF HEAVY
DOWNPOURS.
SHOWER/TS ACTIVITY WILL LIKELY CONTINUE WELL INTO TONIGHT AND INTO
TUESDAY...ESPECIALLY OVER SOUTH-CENTRAL AND SW AZ AS PWATS RISE INTO
THE 1.80-2.00 INCH RANGE...AND UPPER-LEVEL DIFLUENCE DEVELOPS OVER
THE REGION. HEAVY RAIN/LOCALIZED FLOODING WILL LIKELY BE THE MAIN
ISSUE WITH STORMS LATER TONIGHT AND TUESDAY AS THE VERY MOIST
AIRMASS WILL MAKE THEM MORE EFFICIENT RAINFALL PRODUCERS...WITH
LOCALIZED RAINFALL AMOUNTS AOA 1 INCH LIKELY IN A FEW SPOTS. THE
WIDESPREAD RAINFALL/CLOUDINESS IS EXPECTED TO PUSH HIGH TEMPS ON
TUESDAY BACK BELOW NORMAL...WITH MANY LOWER DESERT LOCATIONS ACROSS
SOUTH-CENTRAL AZ REMAINING BELOW 100F.
A BIT OF A BREAK IS LIKELY ON WEDNESDAY AS THE MAIN MOISTURE PLUME
IS PUSHED TO THE SOUTH AND EAST BY THE APPROACHING UPPER LOW CENTER
AS IT PUSHES INLAND OVER SOUTHERN CA...BUT SCATTERED THUNDERSTORMS
ARE STILL LIKELY TO DEVELOP OVER THE HIGHER TERRAIN NORTH AND EAST
OF PHOENIX.
THURSDAY THROUGH SATURDAY...
SOME MODEL CONSENSUS IS FINALLY BEGINNING TO SHOW UP DURING THIS
PERIOD. THE EURO IS NOW BEGINNING TO SIDE WITH THE GFS...BY TAKING
THE MAIN UPPER LOW CENTER INLAND INTO AZ/NM...WITH CONSIDERABLE
TROPICAL MOISTURE FROM THE REMAINS OF TROPICAL CYCLONE 12E...WHICH
HAS NOW FORMED WELL SOUTHWEST OF THE TIP OF BAJA CALIFORNIA...MOVING
INTO THE DESERT SOUTHWEST AHEAD OF THIS LOW CENTER. THERE IS STILL
CONSIDERABLE TIMING DIFFERENCES BETWEEN THE TWO MODELS...WITH THE
GFS MOVING THE UPPER LOW CENTER INTO AZ LATE THU NIGHT/EARLY
FRIDAY...WHILE THE MUCH SLOWER EURO MOVES IT INTO AZ ON SATURDAY.
EITHER WAY...IT APPEARS MORE-AND-MORE LIKELY THAT A SIGNIFICANT
RAINFALL EVENT COULD DEVELOP OVER AZ...WITH TEMPS FALLING WELL BELOW
NORMAL...WHICH IS VERY UNUSUAL IN MID-LATE AUGUST. THUS...HAVE
RAISED POPS ACROSS THE BOARD DURING THIS PERIOD.
SUNDAY AND MONDAY...
A RETURN TO A MUCH DRIER...AND WARMER PATTERN IS EXPECTED DURING
THIS PERIOD AS BOTH THE GFS AND EURO BEGIN TO DIG A BROAD LONG-WAVE
TROF SOUTHWARD INTO THE INTERMOUNTAIN WEST...WITH WESTERLY FLOW
ALOFT ADVECTING MUCH DRIER AIR INTO THE REGION.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA...KSDL...
INCREASING MONSOONAL MOISTURE FROM THE SOUTH WILL LEAD TO BETTER
CHANCES FOR STORMS THIS AFTERNOON AND OVERNIGHT TONIGHT. TIMING OF
THUNDERSTORMS IS SOMEWHAT UNCERTAIN...SO FOR THE MOMENT WILL JUST
KEEP VCTS IN THE TAFS AFTER 01Z...WITH A TRANSITION TO VCSH AFTER
ABOUT 06Z...WITH BKN MID/UPPER LEVEL CLOUD DEBRIS CLOUD DECKS. THERE
IS POTENTIAL LATER TODAY AND THIS EVENING FOR GUSTY VARIABLE OUTFLOW
WINDS...DENSE BLOWING DUST...RESTRICTED VISIBILITY AS WELL AS STORMS
AT THE TERMINALS.
SOUTHWEST ARIZONA AND SOUTHEAST CALIFORNIA INCLUDING KIPL AND KBLH...
SCT TO BKN MID AND HIGH CLOUDS...WITH BASES AOA 10 KFT ARE EXPECTED
THROUGH TUE MORNING. WINDS SHOULD FAVOR THE SOUTH OR SOUTHEAST NEXT
24 HOURS AT BOTH TAF SITES. GUSTS TO AROUND 22 KT CAN BE EXPECTED
MID TO LATE AFTN AT KBLH.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
WEDNESDAY THROUGH SUNDAY...
DEEP MONSOON MOISTURE WILL CONTINUE THIS PERIOD WITH HIGHER THAN
NORMAL RELATIVE HUMIDITY. A GOOD CHANCE OF AFTERNOON AND EVENING
THUNDERSTORMS ARE EXPECTED OVER HIGHER MOUNTAINS OF SOUTHERN GILA
COUNTY EACH DAY...WITH A SLIGHT CHANCE OF THUNDERSTORMS ON THE LOWER
SOUTHWEST AND SOUTH CENTRAL DESERTS. MINIMUM RELATIVE HUMIDITIES WILL
RANGE FROM 25 TO 30 PERCENT. OVERNIGHT RECOVERY WILL BE GOOD.
AFTERNOON TEMPERATURES WILL BE BELOW NORMAL THIS PERIOD ESPECIALLY
FROM PHOENIX EASTWARD. ADDITIONALLY...AFTERNOON/EARLY EVENING WINDS
WILL BE SOUTHWESTERLY AND GENERALLY UNDER 20 MPH...EXCEPT NEAR
THUNDERSTORMS.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...VASQUEZ/PERCHA
AVIATION...MCLANE/CB
FIRE WEATHER...VASQUEZ/CB
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST MON AUG 18 2014
.SYNOPSIS...AMPLE MOISTURE WILL PROVIDE SCATTERED TO NUMEROUS
THUNDERSTORMS THIS WEEK. SOME STORMS WILL PRODUCE GUSTY WINDS AND
HEAVY HEAVY RAIN THAT MAY PRODUCE FLASH FLOODING. DAYTIME
TEMPERATURES WILL BE BELOW AVERAGE BY MIDWEEK.
&&
.DISCUSSION...IR/VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATE PARTLY CLOUDY SKIES ACROSS ERN SECTIONS TO CLOUDY SKIES
ACROSS WRN PIMA COUNTY. DEWPOINTS AT LOWER ELEVATIONS VALID 16Z
RANGED FROM THE UPPER 50S-MID 60S F...AND THESE TEMPS WERE NEARLY
IDENTICAL TO 24 HOURS AGO. SURFACE TEMPS WERE GENERALLY 2-6 DEGS F
COOLER VERSUS THIS TIME SUN.
18/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS 1.51 INCHES. A
FAIRLY UNSTABLE ENVIRONMENT EXISTED WITH LIFTED INDEX OF MINUS 6 AND
UNMODIFIED SURFACE-BASED CAPE OF 1639 J/KG. HAVE NOTED THE
CONSIDERABLY STRONGER MID-LEVEL SELY STEERING FLOW FOR THUNDERSTORMS
VERSUS THE PAST 2-3 DAYS. 18/12Z UPPER AIR PLOTS DEPICTED A BROAD
RIDGE OVER THE SWRN CONUS WITH 591 DM HIGH PRESSURE CENTERED OVER
THE FOUR CORNERS REGION. LIGHT TO MODERATE GENERALLY ELY/SELY FLOW
PREVAILED IN THE SURFACE-400 MB LAYER WITH MODERATE WLY FLOW ABOVE
400 MB.
18/14Z RUC HRRR...18/12Z NAM AND 18/12Z UNIV OF AZ WRF-NAM WERE
SIMILAR WITH DEVELOPING SHOWERS/TSTMS BY EARLY THIS AFTERNOON MOSTLY
NEAR THE INTERNATIONAL BORDER ADJACENT SANTA CRUZ/COCHISE COUNTIES.
SHOWERS/TSTMS ARE THEN PROGGED TO MOVE NWWD INTO SOUTH CENTRAL AZ BY
AROUND MIDNIGHT TONIGHT. THIS SCENARIO SEEMS QUITE VIABLE GIVEN THE
AFOREMENTIONED STRONGER MID-LEVEL STORM STEERING FLOW AS OBSERVED
VIA THE 18/12Z KTWC SOUNDING.
BASED ON THESE SOLUTIONS AS WELL AS COORD WITH WFO PSR...HAVE OPTED
TO INCREASE THE INHERITED POPS FOR THIS AFTERNOON THRU TUE. BASED ON
THE COMP REFLECTIVITY/10M WIND SIGNATURES AS PER THE UNIV OF AZ
WRF-NAM...HAVE ADDED AREAS OF BLOWING DUST FOR SOUTH CENTRAL PINAL
COUNTY /AZZ505/ THIS EVENING. MAY OPT TO ISSUE A BLOWING DUST
ADVISORY LATER TODAY FOR SOUTH CENTRAL PINAL COUNTY IF SUBSEQUENT
RUC HRRR AND UNIV OF AZ WRF-GFS SOLUTIONS MIMIC THE UNIV OF AZ
WRF-NAM SOLUTION.
ALSO...BASED THUS FAR ON THE 18/12Z NAM...AM GIVING CONSIDERATION
TOWARD THE POTENTIAL ISSUANCE OF A FLASH FLOOD WATCH MAINLY FOR
LOCALES EAST OF TUCSON TUE. WILL ADDRESS THIS NOTION FURTHER IN THE
AFTERNOON DISCUSSION. OTHERWISE...HIGH TEMPS THIS AFTERNOON SHOULD
AVERAGE ABOUT 3-5 DEGS F COOLER VERSUS TEMPS ACHIEVED SUN.
PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 19/18Z.
EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP SOUTHEAST-TO-
SOUTHWEST OF KTUS BY EARLY THIS AFTERNOON. SCATTERED TO NUMEROUS
-TSRA/-SHRA WILL THEN OCCUR THIS AFTERNOON AND THIS EVENING. MVFR
VISIBILITIES AND BRIEF WIND GUSTS OF 45-50 KTS WILL OCCUR WITH THE
STRONGER TSRA. SCATTERED -SHRA AND ISOLATED -TSRA WILL PREVAIL LATE
TONIGHT INTO TUESDAY MORNING. OTHERWISE...CLOUD DECKS WILL MAINLY BE
AT 6-12K FT AGL AND SURFACE WIND GENERALLY BE LESS THAN 10 KTS THRU
TUESDAY MORNING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...SCATTERED TO NUMEROUS THUNDERSTORMS WILL OCCUR THIS
WEEK AS AMPLE MOISTURE REMAINS ACROSS SOUTHEAST ARIZONA. THE
STRONGER THUNDERSTORMS WILL PRODUCE STRONG...GUSTY AND ERRATIC
WINDS. OTHERWISE...AFTERNOON MINIMUM RELATIVE HUMIDITIES ARE
FORECAST TO BE MOSTLY IN THE 25-50 PERCENT RANGE AT LOWER ELEVATIONS
FOLLOWED BY GOOD TO EXCELLENT OVERNIGHT RECOVERIES. 20-FOOT WINDS
WILL EXHIBIT NORMAL DIURNAL TRENDS AND BE MOSTLY LESS THAN 15 MPH.
&&
.PREV DISCUSSION...WEDNESDAY...UPPER LOW IS FORECAST TO BE ALONG OR
JUST OFF THE SRN CA CST. MOIST SOUTHERLY FLOW CONTINUES ACROSS SRN
AZ...BUT COULD ALSO SEE SOME DRIER AIR PUSH INTO THE SWRN PART OF
THE STATE. WILL CONTINUE CHANCE OF AFTERNOON/EVENING STORMS.
DEPENDING ON HOW MUCH RAIN FALLS ON TUESDAY WILL HAVE A PART IN
DETERMINING HOW WARM IT WILL GET. 00Z MOS GUIDANCE COOLER THAN WHAT
WE ARE FORECASTING. AGAIN WILL NOT MAKE ANY CHANGES HERE.
THURSDAY INTO THE UPCOMING WEEKEND...STILL SOME UNCERTAINTY OF WHEN
OR IF THE SRN CA UPPER LOW WILL LIFT THRU THE STATE. GFS SAYS
THURSDAY...ECMWF SAYS FRIDAY...CANADIAN KEEPS IT OFFSHORE. WITH SUCH
UNCERTAINTY...WILL MAINTAIN NEAR CLIMO POPS DURING THIS PERIOD.
OVERALL STILL SHAPING UP TO BE A WET WEEK ACROSS SE AZ WITH FLASH
FLOODING A CONCERN MOST OF THE WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
FRANCIS
PREVIOUS DISCUSSION...GLUECK
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
937 AM PDT Mon Aug 18 2014
.Synopsis...
Cooler temperatures with a slight chance of mountain thunderstorms
next few days.
.Discussion...
Forecast on track this morning. Instability expected in northern
higher terrain today and also down south into highest elevations
of western Tehama and Glen county. But expecting the most
impactful activity to really remain north and west of Sacramento
forecast area. We have expanded the coverage of isolated
thunderstorms a bit to match this thinking. With light to
southeast steering flow...activity that does fire should remain on
the crest areas and drift into Eureka area late this afternoon. We
are messaging this best we can in FWF product. Supporting this
though are all the HiRes models...which HRRR seems to be a little
underdone but ARW/NMM HiRes models showing isolated coverage in
these areas.
.Previous Discussion...
Clear skies across interior NorCal early this morning with
temperatures and surface pressure gradients nearly identical to
24 hours ago. Marine layer remains under 1500 ft in depth at Ft
Ord, but satellite imagery shows a little more stratus in the east
Bay into western portions of the Carquinez Strait.
Weak upper low now along the central Oregon coast is forecast to
drop southward off the NorCal coast early this week before ending
up vicinity SoCal by mid-week. A few thunderstorms developed
Sunday afternoon and evening across far northern California, and
it is expected that a few storms will develop again later this
afternoon and evening further south into northern Shasta County
and the northern Coast Range. This same area may see a few storms
again on Tuesday afternoon/evening with perhaps a few storms in
the Sierra to the south of Lake Tahoe as well.
Temperatures are forecast to cool a bit the next couple of days as
the low passes to our west resulting in a little synoptic cooling
and stronger onshore flow as the marine layer deepens a bit. More
settled weather returns to the mountains by mid-week as the low
shifts south. Temperatures are forecast to remain around normal
through next weekend as a weak trough over the interior West
maintains onshore flow.
&&
.Extended Discussion (Friday through Monday)
Medium-range models continue to struggle with the evolution of the
cutoff low beyond Wednesday. The GFS weakens the system and
eventually phases it in with a Pacific Northwest trough late this
week. The ECMWF and GEM keep the low stronger off the Baja
California coast, and eventually retrograde it westward as high
pressure builds over the Desert Southwest. Both solutions are dry
for Northern California, but the EC and GEM would be substantially
warmer than what the GFS shows. Our forecast is a blend of the
two very different solutions, with hopes of improving model
consensus soon.
Dang
&&
.Aviation...
VFR conditions the next 24 hours across interior Northern
California, except local IFR conditions west of KSUU early
this morning. Winds will remain below 12 kt across Valley TAF
sites, with local SW winds 10-20 kt near the Delta and over higher
elevations. Dang/JBB
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
335 PM MDT MON AUG 18 2014
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 333 PM MDT MON AUG 18 2014
BIG CHANGES WILL OCCUR OVER THE NEXT 24 HOURS AS AN UNSEASONABLY
STRONG AND NEARLY VERTICALLY STACKED TROUGH...CURRENTLY OVER
CALIFORNIA...MOVES EAST INTO THE GREAT BASIN. THIS BRINGS EASTERN
UTAH AND WESTERN COLORADO INTO IDEAL POSITION FOR DEEP
SUBTROPICAL MOISTURE TO ADVECT INTO THE REGION. PRECIPITABLE
WATER VALUES OF 1 TO 1.3 INCH ARE EXPECTED TO COVER EASTERN UTAH
AND EVEN EXTREME WESTERN COLORADO BY LATE TUESDAY AFTERNOON. THIS
IS ALMOST 2 STANDARD DEVIATIONS ABOVE NORMAL FOR THIS TIME OF
YEAR.
MODELS ARE FORECASTING MULTIPLE VORT MAXES TO REACH THE UT/CO
BORDER THROUGHOUT THE DAY FROM NOON TO MIDNIGHT. THERE IS SOME
UNCERTAINTY ON THE TIMING OF H3 JET SUPPORT OF 60KTS REACHING THE
AREA...WHICH WILL HELP TO PROVIDE ASCENT IN THE UNIMPRESSIVE CAPE
AND SHEAR ENVIRONMENT. EXPECTING CLOUD COVER TO HINDER INSTABILITY
DURING THE DAY...HOWEVER THIS SCENARIO COULD CHANGE IF SUFFICIENT
CLEAR AIR IS ABOUND BY LATE MORNING. THE RAP SHOWS JET SUPPORT
INCHING INTO EASTERN UTAH AND SOUTHWEST COLORADO DURING THE
MORNING ON TUESDAY...HOWEVER THE NAM AND GFS SHOW THE BEST JET
SUPPORT ON TUESDAY NIGHT AND WEDNESDAY MORNING. STORM MOTION WILL
BE DECENT FOR TUESDAY - ABOUT 20 TO 30 KTS...SO COULD NOT JUSTIFY
A FLASH FLOOD WATCH AT THIS TIME. IT WILL RAIN IN MANY LOCATIONS
BY TUESDAY NIGHT...BUT ONLY EXPECTING MODERATE TO HEAVY RAIN
MULTICELLULAR STORMS CAUSING NUISANCE/SMALL STREAM FLOODING AT
THIS TIME. SEE HYDRO SECTION FOR MORE.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 333 PM MDT MON AUG 18 2014
THE FORECAST AREA REMAINS UNDER SW FLOW WED-THU WITH THE JET AXIS
OVERHEAD. MONSOONAL MOISTURE PLUME WEAKENS WITH PRECIPITABLE WATER
VALUES DROPPING UNDER 1 INCH. NAM/GFS SHOW A WEAK 300 MB JET MAX
ARRIVING ON WED FOR POTENTIAL SUPPORT AND INCREASED VERTICAL
SHEAR....AND SHOULD IT ENTRAIN SOME DRIER MIDLEVEL AIR OVER HIGHER
MOISTURE NEAR THE SURFACE...IT COULD LEAD TO SOME STRONGER STORMS
WED AFTERNOON.
MODELS STILL HAVING TROUBLE HANDLING THE UPPER LOW THAT IS
CURRENTLY DROPPING SOUTH ALONG THE NRN CA COAST...WHICH LOWERS
FORECAST CONFIDENCE AFTER MIDWEEK. BUT AT LEAST THE GFS AND ECWMF
NOW BOTH BRING THE 500 MB LOW INLAND...JUST TIMING AND TRACK ARE
DIFFERENT. THE 12Z GFS SWINGS THE LOW INLAND ACROSS SRN CA WED AND
THEN LIFTS IT NE ACROSS UT AS AN OPEN WAVE ON THU. THIS COULD ADD
SOME DYNAMIC PUNCH TO STORM DEVELOPMENT ON THU. THE 12Z ECMWF IS
SLOWER BRINGING IT INLAND AND TRACKS IT FARTHER SOUTH ACROSS AZ
AND NWRN NM. THE 12Z CANADIAN HAS IT SHEARING OUT ALONG THE SRN CA
COAST THU-FRI. MODELS ALSO SHOW ENERGY DROPPING OUT OF THE GULF OF
AK LATE IN THE WEEK THAT SHOULD MAINTAIN TROUGHING OVER THE PAC
NW/NRN ROCKIES.
FOR NOW...WITH FOLLOW THE CONSENSUS MODEL TREND...WHICH SHOWS A
LESSENING OF STORM COVERAGE THE LAST HALF OF THE WEEK BUT NOT A
COMPLETE CESSATION. LOWER LEVEL MOISTURE LIKELY TO LINGER WITH SOME
SMALLER EMBEDDED WAVES IN THE FLOW THAT COULD TRIGGER ISOLATED-
SCATTERED ACTIVITY ABOUT EACH DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1108 AM MDT MON AUG 18 2014
A LINE OF -SHRA SOUTH OF KCAG BUT NORTH OF THE BOOKCLIFFS
CONTINUES TO MOVE EAST THROUGH THE AREA THANKS TO A WEAK WEATHER
DISTURBANCE ACROSS NORTHERN COLORADO. ISOLATED -RA/-TSRA WILL
INCREASE IN COVERAGE OVER THE MOUNTAINS AROUND 18Z. KEGE AND KASE
HAVE A SLIGHT CHANCE OF RECEIVING A SHOWER OR THUNDERSTORM TODAY.
MOISTURE WILL INCREASE AFTER 12Z TUESDAY MORNING FROM THE
SOUTHWEST AND INCREASE THE COVERAGE OF RAIN SHOWERS AND
THUNDERSTORMS BY 18Z TUESDAY.
&&
.HYDROLOGY...
ISSUED AT 333 PM MDT MON AUG 18 2014
MONSOONAL MOISTURE WILL RETURN TOMORROW AS AN UPPER LEVEL LOW OVER
CALIFORNIA PULLS DEEP SUBTROPICAL MOISTURE INTO THE REGION.
SHOWERS AND THUNDERSTORMS WILL INCREASE IN COVERAGE FROM WEST TO
EAST THOUGHOUT THE AFTERNOON AND PEAK DURING THE LATE HOURS OF THE
DAY AND OVERNIGHT INTO WEDNESDAY MORNING. EXPECTING TO HAVE SMALL
STREAM AND ARROYO FLOOD ISSUES BY WEDNESDAY MORNING IN THE USUAL
PROBLEM AREAS...BUT AT THIS NOT EXPECTING HIGH COVERAGE OF
TORRENTIAL DOWNPOURS DUE TO THUNDERSTORMS. THEREFORE...NO WATCHES
HAVE BEEN ISSUED AT THIS TIME.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...JAM
LONG TERM...JAD
AVIATION...JAM
HYDROLOGY...JAM
AREA FORECAST DISCUSSION
NWS PUEBLO CO
322 PM MDT MON AUG 18 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 259 PM MDT MON AUG 18 2014
THE UPR RIDGE IS STILL CENTERED NR THE FOUR CORNERS AREA TODAY
AND PRECIPITABLE WATER VALUES ARE SIMILAR TO WHAT THEY WERE
YESTERDAY. ISOLATED SHOWERS AND TSTMS HAVE DEVELOPED OVR SOME OF
THE MOUNTAIN AREAS AS OF 1930Z. SHOULD SEE COVERAGE OVR THE MTNS
INCREASE THIS AFTERNOON. HRRR AND RAP SHOW PCPN DEVELOPING/MOVING
OVR THE SERN PLAINS AND PORTIONS OF THE SAN LUIS VALLEY LATER THIS
AFTERNOON AND THIS EVENING. THE HRRR AND RAP HAVE PCPN ENDING IN
MOST LOCATIONS BY LATE EVENING...BUT SHOW THE POTENTIAL FOR SOME
CONTINUING OVR THE SAN JUAN MTNS INTO THE LATE NIGHT HOURS.
AS AN UPR TROF DIGS INTO SRN CA TONIGHT AND TUESDAY...THE UPR RIDGE
OVR OUR AREA SHIFTS EASTWARD. THIS PUSHES A LITTLE BETTER MSTR INTO
WRN CO FOR TUE...WITH PRECIPITABLE WATER VALUES INCREASING SLIGHTLY
OVR THE CONTDVD. AS A RESULT THERE SHOULD BE MORE WIDESPREAD SHOWER
AND TSTM ACTIVITY ALONG THE CONTDVD TOMORROW. THE ERN MTNS WL
LIKELY SEE SCT PCPN DEVELOPING IN THE AFTERNOON HOURS...WHILE THE
SERN PLAINS SHOULD JUST SEE A FEW SHOWERS OR STORMS DEVELOP. HIGH
TEMPS ON TUE SHOULD BE 5-8 DEGREES ABOVE AVERAGE OVR THE SERN
PLAINS...AND AROUND NORMAL IN THE SAN LUIS VALLEY AND UPR ARKANSAS
RIVER VALLEY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 259 PM MDT MON AUG 18 2014
...ACTIVE WEATHER FOR AT LEAST THE NEXT WEEK...
MODELS ARE NOW IN REASONABLE AGREEMENT THAT THE CUTOFF LOW
OFF THE CA COAST WILL PHASE WITH THE TROUGH MOVING INTO THE
PACNW...AND THIS WILL LEAD TO AN ENHANCED MONSOONAL PATTERN
FOR THE LATTER PART OF THIS WEEK AND BEYOND. A COUPLE OF
ADDITIONAL SHORTWAVES WILL MOVE THROUGH THE LONGWAVE TROUGH
PATTERN THAT IS OVER WRN CANADA...BRINGING THE THREAT FOR PERIODS
OF HEAVY RAIN TO OUR AREA.
TUE NIGHT...EXPECT ISOLD STORMS TO PERSIST OVER THE CONTDVD
AS THE PLUME BEGINS TO MOVE OVR WRN CO. BY LATE WED THE TROUGH
AND ABSORBED CUTOFF WILL MOVE INTO NW AZ/SW UT...AND THE THREAT
OF HEAVY BANDS OF CONVECTION WILL CONTINUE FOR THE SW MTS AND
CONTDVD. DEPENDING ON WHAT HAS ALREADY FALLEN OVR THE MTS
WE COULD SEE THE THREAT OF MORE FLASH FLOODING AND RISK OF
SLIDES FOR THE MT AREAS. TIMING FOR OUR CWA`S STAGES IN THE
PRO CYCLING CHALLENGE DOES NOT LOOK FAVORABLE AS THE STRONGEST
DYNAMICS FROM THIS SYSTEM MOVE THROUGH ON THURSDAY. THAT IS WHEN
THE CORE OF A 100 KT JET STREAK MOVES THROUGH CO. THIS IS PRETTY
ROBUST FOR AN AUGUST SYSTEM. WITH H6 TEMPS AT MINUS 2C OR LOWER IN
THE CORE OF THE LOW...COULD EASILY SEE SOME SNOW FOR ELEVS ABOVE
12K FEET BY FRI MORNING. THE GFS BRINGS US A BIT OF A BREAK IN THE
ACTION ON SATURDAY BEFORE ANOTHER FRONT COMES THROUGH SAT
NIGHT...FOLLOWED BY A THIRD SYSTEM SUN OR MON. THE ECMWF HAS SOME
OF THE HEAVIEST QPF ON FRI AND CONTINUES THE ONSLAUGHT THROUGH THE
WEEKEND. A BIT HARD TO SAY WHEN THE HEAVIEST RAIN WILL FALL...BUT
THE THREAT OF HEAVY PRECIP WILL CERTAINLY BE WITH US SO LONG AS
THIS PARADE OF SHORTWAVES CONTINUE...AT LEAST THROUGH THE FIRST
DAYS OF NEXT WEEK. ENSEMBLE POPS LOOKED MUCH TOO LOW SO HAVE
RAISED POPS BY AT LEAST 10 PERCENT OVER THIS TIME FRAME FOR BOTH
THE PLAINS AND MTS...WHILE THE MTS WILL SEE THE BEST SHOT AT HEAVY
PRECIP. TEMPS WILL TREND DOWNWARD THROUGH THE PERIOD...STARTING IN
THE NR 90 RANGE FOR TUE-THU...AND THEN FALLING INTO THE 80S AND
POSSIBLY LOWER FOR THE PLAINS NEXT WEEKEND. LOOKS LIKE THE
FORECAST WILL REMAIN CHALLENGING FOR THE REST OF THIS MONTH. ROSE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 259 PM MDT MON AUG 18 2014
VFR CONDITIONS ARE EXPECTED AT KCOS...KPUB AND KALS TONIGHT THROUGH
TUESDAY AFTERNOON. TSTMS COULD MOVE INTO THE VCNTY OF THE TERMINAL
SITES THIS EVENING...WITH KCOS SEEING THE BEST CHANCE OF THIS
OCCURRING. SHOWERS AND TSTMS WL AGAIN DEVELOP OVR THE MOUNTAINS AND
THEN SPREAD OVR SOME OF THE LOWER ELEVATIONS...POSSIBLY MOVING IN
THE VCNTY OF THE TERMINAL SITE.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...ROSE
AVIATION...28
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
147 PM EDT MON AUG 18 2014
.SYNOPSIS...
A FRONTAL BOUNDARY WILL STALL OVER VIRGINIA TODAY. A WAVE OF LOW
PRESSURE WILL TRACK EASTWARD ALONG THE STALLED BOUNDARY TONIGHT
BEFORE MOVING OFFSHORE TUESDAY. THE FRONTAL BOUNDARY SHOULD REMAIN
NEARLY STATIONARY FROM THE GREAT LAKES TO THE SOUTHERN MID-ATLANTIC
STATES WEDNESDAY AND THURSDAY WHILE A SERIES OF DISTURBANCES RIDE
ALONG IT. THE FRONT WILL GRADUALLY SHIFT FARTHER SOUTH AND WEST OF
THE AREA FRIDAY AND THIS WEEKEND AS HIGH PRESSURE WEDGES DOWN FROM
EASTERN CANADA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST WATER VAPOR AND 11-3.9 IR SHOW THE QUASI-STATIONARY FRONTAL
BOUNDARY TO OUR SOUTH EXTENDING NORTHEAST INTO THE MARYLAND/WEST
VIRGINIA PANHANDLE. DRY AIR WILL CONTINUE TO PRESS INTO THE REGION
FROM THE NORTH THROUGH THE MORNING HOURS UNDER A LIGHT NORTHERLY
FLOW. WINDS ARE EXPECTED TO VEER TOWARDS THE WEST-SOUTHWEST LATER
THIS AFTERNOON AS THE FRONT WAVERS TO OUR SOUTH. A WEAK SURFACE LOW,
CURRENTLY ACROSS THE MID-WEST, WILL RIDE ALONG THIS FRONTAL BOUNDARY
LATER THIS AFTERNOON..STAYING TO THE SOUTH OF OUR CWA. BASED ON
THE LATEST RAP AND HRRR WITH THE 12:30 PM UPDATE, PUSHED BACK ANY
RAIN CHANCE TILL TONIGHT ACROSS THE SOUTHERN DELMARVA.
ELSEWHERE, THE LOWER PWAT AIR IN PLACE WILL TAKE A WHILE TO
MODIFY SO WE EXPECT A DRY DAY WITH SOME INCREASING CLOUD COVER
LATE IN THE DAY. TEMPERATURES WILL RUN CLOSE TO NORMAL TODAY, LIKE
THE PAST FEW DAYS. DID MAKE SOME MINOR ADJUSTMENTS ON THE
TEMPERATURES WITH THE 12;30 PM UPDATE BASED ON THE 16Z METARS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
THE SURFACE WAVE ALONG THE FRONTAL BOUNDARY WILL PASS TO OUR SOUTH
LATE TONIGHT. THIS SYSTEM OVER THE PAST SEVERAL DAYS HAS TRENDED
TOWARDS A MORE SUPPRESSED, FASTER WEST-EAST MOVEMENT, AND A
SOUTHEASTERN TRACK THAT WOULD ALLOW FOR LESS SIGNIFICANT RAINFALL
THREAT THEN PREVIOUSLY THOUGHT...WE REMOVED THE MENTION FROM THE HWO
AT THIS TIME.
SURFACE FLOW BEGINS TO VEER TOWARDS THE EAST-SOUTHEAST BY THIS
EVENING BRINGING MORE LOW-LEVEL INTO THE REGION...EVERYWHERE. NOT
EXPECTING MUCH IN THE WAY OF RAIN CHANCES LATE TONIGHT, OUTSIDE OF
THE DELMARVA, WITHOUT MUCH SYNOPTIC SCALE LIFT AND DON`T THINK THE
SURFACE FLOW IS STRONG ENOUGH FOR UPGLIDE ACROSS OUR WESTERN ZONES,
SO WE STAY MOSTLY DRY TONIGHT. TEMPERATURES, UNDER INCREASINGLY
CLOUDY SKIES, WILL BE SEVERAL DEGREES WARMER THAN THE PAST FEW
MORNINGS...BLEND OF THE MET/MAV LOOKS GOOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
WHILE OPPRESSIVE HEAT WILL BUILD ACROSS THE SOUTHERN CONUS IN
ASSOCIATION WITH A STRENGTHENING ANTICYCLONE THIS WEEK, IT IS NOT
EXPECTED TO REACH OUR AREA THROUGH THE NEXT 7 DAYS AS THE REGION
WILL GENERALLY BE UNDER THE PRESENCE OF MEAN TROUGHING AND ONSHORE
FLOW AT THE SFC. TEMPS THRU THE PERIOD SHOULD BE NEAR TO SLIGHTLY
BELOW NORMAL FOR THIS TIME OF YEAR.
LOPRES IS EXPECTED TO MOVE OFF THE SOUTHEAST VA COAST TUESDAY
MORNING. MODELS CONTINUE THE TREND TOWARD A WEAKER, MORE PROGRESSIVE
SYSTEM, WHICH WILL RESULT IN A EARLIER END TO THE SHOWERS ACROSS THE
DELMARVA DURING THE MORNING. THERE MAY ALSO BE AN ISOLATED SHOWER
THAT DEVELOPS ACROSS THE HIGHER ELEVATIONS OF PA LATE IN THE DAY,
BUT THE BULK OF DIURNAL CONVECTION SHOULD BE CENTERED CLOSER TO THE
SHARPENING LLVL THETA-E RIDGE, WHICH WILL RESIDE WEST OF THE AREA.
OTHERWISE, DRY CONDITIONS PREVAIL. FCST MAX TEMPS RANGING FROM THE
MID 70S IN THE POCONOS TO MID 80S ALONG THE I-95 CORRIDOR ARE CLOSE
TO CLIMO.
A WEAK RIDGE OF HIPRES BECOMES ESTABLISHED ACROSS THE COASTAL MID
ATLANTIC TUESDAY NIGHT AND WEDNESDAY MORNING. ALTHOUGH MODEL
GUIDANCE HASN`T JUMPED ON IT YET, WILL HAVE TO WATCH FOR THE
POTENTIAL FOR FOG OR STRATUS DEVELOPMENT AS PERSISTENT ONSHORE FLOW
IN THE BOUNDARY LAYER DRAWS MARINE AIR INLAND.
THE NEXT SYSTEM TO IMPACT THE AREA WILL BE A WAVE OF LOPRES OVER THE
GREAT LAKES THAT MOVES SOUTHEASTWARD ALONG THE STALLED FRONTAL
BOUNDARY IN THE MID-ATLANTIC STATES WEDNESDAY AFTERNOON THROUGH
THURSDAY. THE DISTURBANCE IS ALSO FORECAST TO WEAKEN AS THE UPPER
LOW BECOMES AN OPEN WAVE BY THE TIME IT REACHES OUR AREA. THIS LOW
OF PAC NW ORIGIN IS NOT EXPECTED TO TAP INTO APPRECIABLE GULF OF
MEXICO MOISTURE DURING ITS CROSS-COUNTRY TREK. ACCORDINGLY, THE SETUP
DOES NOT PARTICULARLY SUPPORT A HEAVY RAINFALL EVENT OR A WASHOUT,
BUT THERE IS STILL A CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE
SECOND HALF OF THE WORK WEEK. CHANCE POPS INITIALLY CONFINED TO WEST
OF I-95 WEDNESDAY AFTERNOON, BEFORE THIS ACTIVITY WOULD TRY TO
ADVANCE EASTWARD INTO THE REST OF THE CWA WEDNESDAY NIGHT. POPS
THURSDAY HIGHEST CLOSER TO THE STATIONARY BOUNDARY OVER THE
DELMARVA/NORTHEAST MD/SOUTHEAST PA.
A RIDGE OF HIPRES OVER EASTERN CANADA IS EXPECTED TO NOSE DOWN INTO
THE FORECAST AREA FRIDAY THROUGH THE WEEKEND. MODELS NOW SHOW THE
HIGH BECOMING ESTABLISHED ALONG THE EASTERN SEABOARD SOONER THAN
PREVIOUS GUIDANCE HAD INDICATED. TRENDED TOWARD A DRIER FORECAST
FRIDAY INTO THE WEEKEND AS THE HIGH SHOULD ACT TO SHIFT THE OLD
FRONTAL BOUNDARY AND STORM TRACK SOUTH AND WEST OF THE AREA. ONSHORE
FLOW WOULD POSITION THE REGION IN COOLER, MORE STABLE AIRMASS
REGIME.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
SCATTERED MID LEVEL CLOUDS WILL CONTINUE TO MOVE EAST INTO THE
REGION AHEAD OF A LOW PRESSURE SYSTEM PASSING TO OUR SOUTH THIS
AFTERNOON. CEILINGS MAY LOWER TO AROUND 5000 FEET WITH THIS CLOUD
COVER TONIGHT. PRECIPITATION LOOKS TO REMAIN SOUTH OF ALL TAF SITES.
THE CLOUDS SHOULD BREAK UP AND BECOME MORE SCATTERED BY TOMORROW
AFTERNOON. WINDS WILL BE VARIABLE THIS AFTERNOON WITH SOME
UNCERTAINTY IN THE WIND DIRECTION BUT WINDS SHOULD REMAIN UNDER
10 KNOTS. A SLIGHT CHANCE FOR AN ISOLATED WIND GUST IS PRESENT THROUGH
LATE AFTERNOON BUT SMALL ENOUGH NOT TO INCLUDE IN THE TAFS ATTM. LIGHT
AND VARIABLE WINDS SHOULD TURN MORE OUT THE EAST ON TUESDAY AND
REMAIN UNDER 10 KNOTS.
OUTLOOK...
TUESDAY NIGHT THROUGH WEDNESDAY MORNING...STRATUS OR FOG
POSSIBLE AS ONSHORE FLOW DEVELOPS. BEST SETUP WOULD BE CLOSER TO
THE COAST (ACY/MIV).
WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...CHANCE FOR SHRA/TSRA AS
A SERIES OF DISTURBANCES MOVE THRU THE REGION. LOCAL/TEMPORARY
FLIGHT RESTRICTIONS POSSIBLE.
FRIDAY...VFR CONDITIONS.
&&
.MARINE...
WE CONTINUE THE TRANQUIL SUB-SCA CONDITIONS TODAY AND TONIGHT. LIGHT
NORTHERLY WINDS WILL BACK TOWARDS THE SOUTH-SOUTHEAST DURING THE
COURSE OF THE DAY, AND REMAIN BELOW 10 KNOTS. SEAS WILL CONTINUE TO
RUN AROUND 2 TO 3 FEET. WINDS THEN VEER TOWARDS THE EAST LATE
TONIGHT AS A WEAK SURFACE LOW PRESSURE SLIDES EASTWARD TO OUR
SOUTH.
OUTLOOK...
TUESDAY...LOPRES MOVES OFF THE VA COAST. A TIGHT PRESSURE GRADIENT
TO THE NORTH OF THE LOW MAY PRODUCE EASTERLY WINDS 15-20 KT. SCA
POTENTIAL LOW.
WEDNESDAY THROUGH THURSDAY...ONSHORE FLOW CONTINUES BUT WILL WEAKEN
OVER TIME. TSRA POSSIBLE IN SOUTHERN WATERS ON THURSDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLEIN
NEAR TERM...GAINES/HEAVENER
SHORT TERM...HEAVENER
LONG TERM...KLEIN
AVIATION...GAINES/HEAVENER/KLEIN
MARINE...HEAVENER/KLEIN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1224 PM EDT MON AUG 18 2014
.SYNOPSIS...
A FRONTAL BOUNDARY WILL STALL OVER VIRGINIA TODAY. A WAVE OF LOW
PRESSURE WILL TRACK EASTWARD ALONG THE STALLED BOUNDARY TONIGHT
BEFORE MOVING OFFSHORE TUESDAY. THE FRONTAL BOUNDARY SHOULD REMAIN
NEARLY STATIONARY FROM THE GREAT LAKES TO THE SOUTHERN MID-ATLANTIC
STATES WEDNESDAY AND THURSDAY WHILE A SERIES OF DISTURBANCES RIDE
ALONG IT. THE FRONT WILL GRADUALLY SHIFT FARTHER SOUTH AND WEST OF
THE AREA FRIDAY AND THIS WEEKEND AS HIGH PRESSURE WEDGES DOWN FROM
EASTERN CANADA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST WATER VAPOR AND 11-3.9 IR SHOW THE QUASI-STATIONARY FRONTAL
BOUNDARY TO OUR SOUTH EXTENDING NORTHEAST INTO THE MARYLAND/WEST
VIRGINIA PANHANDLE. DRY AIR WILL CONTINUE TO PRESS INTO THE REGION
FROM THE NORTH THROUGH THE MORNING HOURS UNDER A LIGHT NORTHERLY
FLOW. WINDS ARE EXPECTED TO VEER TOWARDS THE WEST-SOUTHWEST LATER
THIS AFTERNOON AS THE FRONT WAVERS TO OUR SOUTH. A WEAK SURFACE LOW,
CURRENTLY ACROSS THE MID-WEST, WILL RIDE ALONG THIS FRONTAL BOUNDARY
LATER THIS AFTERNOON..STAYING TO THE SOUTH OF OUR CWA. BASED ON
THE LATEST RAP AND HRRR WITH THE 12:30 PM UPDATE, PUSHED BACK ANY
RAIN CHANCE TILL TONIGHT ACROSS THE SOUTHERN DELMARVA.
ELSEWHERE, THE LOWER PWAT AIR IN PLACE WILL TAKE A WHILE TO
MODIFY SO WE EXPECT A DRY DAY WITH SOME INCREASING CLOUD COVER
LATE IN THE DAY. TEMPERATURES WILL RUN CLOSE TO NORMAL TODAY, LIKE
THE PAST FEW DAYS. DID MAKE SOME MINOR ADJUSTMENTS ON THE
TEMPERATURES WITH THE 12;30 PM UPDATE BASED ON THE 16Z METARS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
THE SURFACE WAVE ALONG THE FRONTAL BOUNDARY WILL PASS TO OUR SOUTH
LATE TONIGHT. THIS SYSTEM OVER THE PAST SEVERAL DAYS HAS TRENDED
TOWARDS A MORE SUPPRESSED, FASTER WEST-EAST MOVEMENT, AND A
SOUTHEASTERN TRACK THAT WOULD ALLOW FOR LESS SIGNIFICANT RAINFALL
THREAT THEN PREVIOUSLY THOUGHT...WE REMOVED THE MENTION FROM THE HWO
AT THIS TIME.
SURFACE FLOW BEGINS TO VEER TOWARDS THE EAST-SOUTHEAST BY THIS
EVENING BRINGING MORE LOW-LEVEL INTO THE REGION...EVERYWHERE. NOT
EXPECTING MUCH IN THE WAY OF RAIN CHANCES LATE TONIGHT, OUTSIDE OF
THE DELMARVA, WITHOUT MUCH SYNOPTIC SCALE LIFT AND DON`T THINK THE
SURFACE FLOW IS STRONG ENOUGH FOR UPGLIDE ACROSS OUR WESTERN ZONES,
SO WE STAY MOSTLY DRY TONIGHT. TEMPERATURES, UNDER INCREASINGLY
CLOUDY SKIES, WILL BE SEVERAL DEGREES WARMER THAN THE PAST FEW
MORNINGS...BLEND OF THE MET/MAV LOOKS GOOD.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
WHILE OPPRESSIVE HEAT WILL BUILD ACROSS THE SOUTHERN CONUS IN
ASSOCIATION WITH A STRENGTHENING ANTICYCLONE THIS WEEK, IT IS NOT
EXPECTED TO REACH OUR AREA THROUGH THE NEXT 7 DAYS AS THE REGION
WILL GENERALLY BE UNDER THE PRESENCE OF MEAN TROUGHING AND ONSHORE
FLOW AT THE SFC. TEMPS THRU THE PERIOD SHOULD BE NEAR TO SLIGHTLY
BELOW NORMAL FOR THIS TIME OF YEAR.
LOPRES IS EXPECTED TO MOVE OFF THE SOUTHEAST VA COAST TUESDAY
MORNING. MODELS CONTINUE THE TREND TOWARD A WEAKER, MORE PROGRESSIVE
SYSTEM, WHICH WILL RESULT IN A EARLIER END TO THE SHOWERS ACROSS THE
DELMARVA DURING THE MORNING. THERE MAY ALSO BE AN ISOLATED SHOWER
THAT DEVELOPS ACROSS THE HIGHER ELEVATIONS OF PA LATE IN THE DAY,
BUT THE BULK OF DIURNAL CONVECTION SHOULD BE CENTERED CLOSER TO THE
SHARPENING LLVL THETA-E RIDGE, WHICH WILL RESIDE WEST OF THE AREA.
OTHERWISE, DRY CONDITIONS PREVAIL. FCST MAX TEMPS RANGING FROM THE
MID 70S IN THE POCONOS TO MID 80S ALONG THE I-95 CORRIDOR ARE CLOSE
TO CLIMO.
A WEAK RIDGE OF HIPRES BECOMES ESTABLISHED ACROSS THE COASTAL MID
ATLANTIC TUESDAY NIGHT AND WEDNESDAY MORNING. ALTHOUGH MODEL
GUIDANCE HASN`T JUMPED ON IT YET, WILL HAVE TO WATCH FOR THE
POTENTIAL FOR FOG OR STRATUS DEVELOPMENT AS PERSISTENT ONSHORE FLOW
IN THE BOUNDARY LAYER DRAWS MARINE AIR INLAND.
THE NEXT SYSTEM TO IMPACT THE AREA WILL BE A WAVE OF LOPRES OVER THE
GREAT LAKES THAT MOVES SOUTHEASTWARD ALONG THE STALLED FRONTAL
BOUNDARY IN THE MID-ATLANTIC STATES WEDNESDAY AFTERNOON THROUGH
THURSDAY. THE DISTURBANCE IS ALSO FORECAST TO WEAKEN AS THE UPPER
LOW BECOMES AN OPEN WAVE BY THE TIME IT REACHES OUR AREA. THIS LOW
OF PAC NW ORIGIN IS NOT EXPECTED TO TAP INTO APPRECIABLE GULF OF
MEXICO MOISTURE DURING ITS CROSS-COUNTRY TREK. ACCORDINGLY, THE SETUP
DOES NOT PARTICULARLY SUPPORT A HEAVY RAINFALL EVENT OR A WASHOUT,
BUT THERE IS STILL A CHANCE FOR SHOWERS AND THUNDERSTORMS DURING THE
SECOND HALF OF THE WORK WEEK. CHANCE POPS INITIALLY CONFINED TO WEST
OF I-95 WEDNESDAY AFTERNOON, BEFORE THIS ACTIVITY WOULD TRY TO
ADVANCE EASTWARD INTO THE REST OF THE CWA WEDNESDAY NIGHT. POPS
THURSDAY HIGHEST CLOSER TO THE STATIONARY BOUNDARY OVER THE
DELMARVA/NORTHEAST MD/SOUTHEAST PA.
A RIDGE OF HIPRES OVER EASTERN CANADA IS EXPECTED TO NOSE DOWN INTO
THE FORECAST AREA FRIDAY THROUGH THE WEEKEND. MODELS NOW SHOW THE
HIGH BECOMING ESTABLISHED ALONG THE EASTERN SEABOARD SOONER THAN
PREVIOUS GUIDANCE HAD INDICATED. TRENDED TOWARD A DRIER FORECAST
FRIDAY INTO THE WEEKEND AS THE HIGH SHOULD ACT TO SHIFT THE OLD
FRONTAL BOUNDARY AND STORM TRACK SOUTH AND WEST OF THE AREA. ONSHORE
FLOW WOULD POSITION THE REGION IN COOLER, MORE STABLE AIRMASS
REGIME.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR. LIGHT AND VARIABLE WINDS THROUGH THE FIRST HALF OF THE
DAY BEFORE A SOUTHWEST FLOW ESTABLISHES ITSELF...LESS THAN 10 KNOTS.
SEA BREEZES POSSIBLE AT ACY AND MIV LATER THIS AFTERNOON.
TONIGHT...VFR. LIGHT AND VARIABLE WINDS. LOW-LEVEL MOISTURE BEGINS
TO CREEP BACK INTO THE REGION WITH A THICKENING STRATOCU DECK
POSSIBLE.
OUTLOOK...
TUESDAY...PRECIP EXITS SRN TERMINALS EARLY IN THE DAY AS LOW
PRESSURE MOVES OFF THE VA COAST. VFR CONDITIONS.
TUESDAY NIGHT THROUGH WEDNESDAY MORNING...STRATUS OR FOG POSSIBLE AS
ONSHORE FLOW DEVELOPS. BEST SETUP WOULD BE CLOSER TO THE COAST
(ACY/MIV).
WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...CHANCE FOR SHRA/TSRA AS
A SERIES OF DISTURBANCES MOVE THRU THE REGION. LOCAL/TEMPORARY
FLIGHT RESTRICTIONS POSSIBLE.
FRIDAY...VFR CONDITIONS.
&&
.MARINE...
WE CONTINUE THE TRANQUIL SUB-SCA CONDITIONS TODAY AND TONIGHT. LIGHT
NORTHERLY WINDS WILL BACK TOWARDS THE SOUTH-SOUTHEAST DURING THE
COURSE OF THE DAY, AND REMAIN BELOW 10 KNOTS. SEAS WILL CONTINUE TO
RUN AROUND 2 TO 3 FEET. WINDS THEN VEER TOWARDS THE EAST LATE
TONIGHT AS A WEAK SURFACE LOW PRESSURE SLIDES EASTWARD TO OUR
SOUTH.
OUTLOOK...
TUESDAY...LOPRES MOVES OFF THE VA COAST. A TIGHT PRESSURE GRADIENT
TO THE NORTH OF THE LOW MAY PRODUCE EASTERLY WINDS 15-20 KT. SCA
POTENTIAL LOW.
WEDNESDAY THROUGH THURSDAY...ONSHORE FLOW CONTINUES BUT WILL WEAKEN
OVER TIME. TSRA POSSIBLE IN SOUTHERN WATERS ON THURSDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KLEIN
NEAR TERM...GAINES/HEAVENER
SHORT TERM...HEAVENER
LONG TERM...KLEIN
AVIATION...HEAVENER/KLEIN
MARINE...HEAVENER/KLEIN
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
320 PM EDT MON AUG 18 2014
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
STALLED FRONTAL BOUNDARY STRETCHES FROM THE TN VALLEY TO THE
SOUTHERN MID ATLANTIC STATES. A HIGH PRESSURE RIDGE IS SITUATED
ACROSS NORTHERN FL. 500MB ANALYSIS AND WV LOOP SHOWS A POTENT
SHORTWAVE MOVING EAST ACROSS NORTHERN MS. THIS FEATURE WILL BE THE
FOCUS FOR LATE AFTERNOON AND EVENING CONVECTION ACROSS THE CWFA.
THE 16Z HRRR HAS THE BEST HANDLE ON THE ONGOING CONVECTION THIS
AFTERNOON. HAVE TRIED TO ORIENT THE POPS ACCORDING TO CURRENT RADAR
TRENDS AND CLOSE TO THE HRRR SOLUTION. GOOD INSTABILITY DOES EXIST
AT THE SURFACE...BUT LAPSE RATES REMAIN POOR UNTIL THE COLD POOL
ALOFT MOVES OVERHEAD. BY THE TIME THE SHORTWAVE NEARS THE
CWFA...INSTABILITY HAS DECREASED WITH THE LOSS OF HEATING.
HOWEVER...WITH UNIDIRECTIONAL FLOW...STORMS MAY MOVE REPEATEDLY OVER
THE SAME AREAS...WITH LOCALLY HEAVY RAINFALL POSSIBLE. AREAS TO THE
NORTH RECEIVED ONE TO TWO INCHES OF RAINFALL OVERNIGHT/EARLY THIS
MORNING...SO ANY TRAINING STORMS OR HEAVY RAINFALL MAY CAUSE SOME
LOCALIZED FLOODING.
BY EARLY TUESDAY...THE POTENT EVENING/OVERNIGHT SHORTWAVE WILL HAVE
MOVED OFF TO THE EAST. MODELS ARE PROGGING ANOTHER...WEAKER...
SHORTWAVE TO MOVE EAST IN THE FLOW TOMORROW. CONFIDENCE IS LOW ON
EXACTLY WHERE CONVECTION WILL DEVELOP TOMORROW.
NLISTEMAA
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
LONG TERM FORECAST IS ON TRACK AND HAVE NOT MADE SIGNIFICANT
ADJUSTMENTS. ONE ADDITIONAL POINT TO NOTE IS THAT HEAT INDEX VALUES
ARE CREEPING ABOVE 100 DEGREES SOUTH OF AN ATLANTA TO ATHENS
LINE...WITH PORTIONS OF CENTRAL GEORGIA APPROACHING 105 DEGREES
DURING THE SECOND HALF OF THE WEEK. IF THIS TREND CONTINUES...MAY
NEED A HEAT ADVISORY FOR THESE 105-108 DEGREE VALUES ACROSS THE
SOUTHEAST PART OF THE CWA.
11/ATWELL
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
00Z GFS AND ECMWF ARE IN UNCOMMONLY GOOD AGREEMENT THROUGH THE
EXTENDED FORECAST PERIOD AND CONTINUE THE RECENT TREND OF BUILDING
UPPER-LEVEL HIGH PRESSURE INTO THE CENTRAL GULF COAST REGION AND
LOWER MISSISSIPPI VALLEY FROM MID-WEEK THROUGH NEXT WEEKEND. BY THE
WEEKEND THE UPPER RIDGE IS QUITE STRONG...BUT GEORGIA REMAINS ON THE
EASTERN PERIPHERY. THIS SHOULD ALLOW VERY WARM TEMPERATURES AND
INHIBIT DIURNAL CONVECTION SOMEWHAT...BUT I DO NOT BELIEVE THE
FORECAST AREA IS CLOSE ENOUGH TO THE CENTER OF THE RIDGE TO
ELIMINATE POPS ALTOGETHER.
20
&&
.PREV DISCUSSION... /ISSUED 127 PM EDT MON AUG 18 2014/
AVIATION...
18Z UPDATE...
SCATTERED CONVECTION HAS DEVELOPED IN AREAS THAT HAVE RECEIVED
THE BETTER HEATING THIS MORNING. NO REAL FOCUSING MECHANISM AT THE
SURFACE OR ALOFT. POTENT SHORTWAVE ACROSS NORTHERN MS WILL MOVE
EAST ACROSS AL THIS AFTERNOON. MORE ORGANIZED PRECIP IS POSSIBLE
WITH THIS FEATURE...BUT THE HI-RES MODELS DON`T HAVE A GREAT
HANDLE ON THE SITUATION. WILL LEAVE OUT ANY TEMPO/PROB GROUPS AT
THIS TIME. MODELS ALSO HAVE SOME LOW CLOUDS DEVELOPING...BUT IT
MAY BE LATER DUE TO ANY PRECIP.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 73 91 72 97 / 50 40 30 10
ATLANTA 74 88 73 94 / 40 40 30 10
BLAIRSVILLE 67 84 67 90 / 50 40 30 20
CARTERSVILLE 72 89 71 94 / 50 40 30 10
COLUMBUS 75 92 73 96 / 60 40 30 10
GAINESVILLE 72 89 71 94 / 50 40 30 10
MACON 75 92 72 97 / 50 40 30 10
ROME 72 89 71 95 / 60 40 30 20
PEACHTREE CITY 73 89 71 94 / 50 40 30 10
VIDALIA 77 95 74 97 / 50 40 30 20
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...
LONG TERM....ATWELL
AVIATION...NLISTEMAA
AREA FORECAST DISCUSSION
NWS POCATELLO ID
144 PM MDT MON AUG 18 2014
.DISCUSSION...CENTER OF UPPER LOW OVER NORTHERN CALIFORNIA PER WV
IMAGERY. MOISTURE PULLING NORTH THROUGH NEVADA AND NORTHERN
ARIZONA THROUGH GREAT BASIN TOWARD EASTERN IDAHO. PAIR OF WEAK
SHORTWAVES MOVING THROUGH EAST IDAHO...ONE ALONG DIVIDE AND
ANOTHER ALONG SOUTHERN BORDER. SOME MOISTURE IN PLACE ALREADY AND
CONVECTION HAS BEGUN TO REDEVELOP ALREADY EARLY THIS AFTERNOON
ALONG/AHEAD OF SHORTWAVES. NAM/RAP SEEMS TO HAVE BEST HANDLE ON
CONVECTIVE THREAT THIS AFTERNOON AND EVENING WHILE HRRR STRUGGLING
TO CATCH UP. BOTH NAM/GFS CONTINUE CONVECTION OVERNIGHT INTO EARLY
TUESDAY BUT CONVECTION BLOOMS DURING THE AFTERNOON AS MID LEVEL
MONSOON FLOW REACHES EAST IDAHO. HAVE NUDGED POPS UPWARD TUESDAY
ALL AREAS. SOME DIFFERENCES IN MODELS AS NAM STRONGER WITH
SHORTWAVE EJECTING OUT OF EAST IDAHO TUESDAY NIGHT. DIFFERENCES
AMPLIFY THROUGH THURSDAY WITH NAM A BIT FURTHER SOUTH WITH BASE OF
TROUGH. GFS HOLDS EAST IDAHO IN NEUTRAL FLOW ALOFT WITH SOUTHERN
CUT OFF LOW FURTHER NORTH THAN THE NAM. BOTH MODELS REMAIN
UNSETTLED WITH PLENTY OF MOISTURE IN PLACE TO CONTINUE THREAT OF
SCATTERED THUNDERSTORMS ACROSS THE REGION. SHORTWAVE ROUNDS TROUGH
WEDNESDAY NIGHT INTO THURSDAY FOR ANOTHER WET DAY MOST AREAS WITH
EASTERN IDAHO JUST AHEAD OF MAIN TROUGH AXIS. BOTH MODELS
PRODUCING MORE WIDESPREAD CONVECTIVE CONVERAGE SO NUDGED POPS
UPWARD AGAIN FOR THURSDAY AFTERNOON/EVENING.
ECMWF AND GFS AGAIN DIFFEREING IN DETAILS FOR REMAINDER OF FORECAST.
ECMWF LOOKING AGAIN TO DROP CLOSED SHORTWAVE INTO BASE OF BROAD
PACNW TROUGH THURSDAY NIGHT INTO FRIDAY BUT THEN OPENS IT UP AGAIN
FRIDAY NIGHT. PLACEMENT/DEPTH OF TROUGH SIMILAR WITH HINTS OF DRY
SLOT WORKING IN FROM OREGON FRIDAY INTO SATURDAY. BOTH MODELS
TREAT NORTHERN PACIFIC ENERGY A LITTLE DIFFERENTLY. EAST IDAHO
UNDER SOME INFLUENCE OF BASE OF TROUGH...BUT FLOW RANGES FROM
WEST/DRY IN THE GFS TO NORTHWEST/MOIST IN THE ECMWF. OVERALL OPTED
TO MAKE NO CHANGES TO CURRENT EXTENDED RANGE WITH ISOLATED POPS
CLOSE TO CLIMO AND TEMPS NEAR GUIDANCE BLEND. DMH
&&
.AVIATION...SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH TOMORROW
ACROSS EASTERN IDAHO. COVERAGE WILL BE ISOLATED TODAY BECOMING
CLOSER TO SCATTERED IN SOME AREAS ON TUESDAY. GUSTY WINDS OVER 30KTS
ARE POSSIBLE WITH STORMS...WITH AN INCREASING THREAT OF HEAVY
DOWNPOURS TONIGHT AND TUESDAY. EITHER COULD BRING REDUCED
VISIBILITY. WE WILL BE CARRYING AT LEAST VCTS OR VCSH FOR ALL SITES.
KEYES
&&
.FIRE WEATHER...SHOWERS AND STORMS WILL CONTINUE TO INCREASE ACROSS
EASTERN IDAHO THROUGH THE NEXT 24 HOURS. THUNDERSTORM COVERAGE WILL
BE ISOLATED TODAY AND WIDELY SCATTERED TOMORROW. THE SOUTHEAST
CORNER WILL BE INTERESTING TO WATCH AS THEY MAY BE TOO STABLE TO SEE
ANY THUNDER AT ALL IF CLOUDS AND TIMING MATCH UP. STORMS WILL BE
CAPABLE OF PRODUCING WIND GUSTS OVER 35 MPH AND LOCALLY HEAVY
DOWNPOURS. WE ARE NOT EXPECTING ANY ISSUES WITH SLIDES OR FLOODING
THIS TIME AROUND. ISOLATED TO WIDELY SCATTERED THUNDERSTORMS WILL
CONTINUE THROUGH THE END OF THE WEEK AS THE LOW OUT OF CANADA SAGS
SOUTH INTO THE NORTHERN STATES. THE BETTER CHANCES WEDNESDAY-FRIDAY
WILL BE ACROSS THE NORTH AND ALONG THE WYOMING BORDER. DRIER
CONDITIONS WILL FILTER INTO PORTIONS OF THE SNAKE PLAIN AND
SOUTH-CENTRAL HIGHLANDS...HELPING TO REDUCE SHOWERS/STORMS. WE WILL
ALSO SEE THE WIND PICKING UP...BUT INCREASED HUMIDITY SHOULD NEGATE
THIS AND PREVENT ANY ISSUES WITH CRITICAL FIRE CONDITIONS. THE
MODELS CONTINUE TO SHOW WIDELY VARYING FORECASTS EACH DAY IN THE
EXTENDED...BUT ONE TREND IS EMERGING DESPITE ALL OF THIS. IT DOES
APPEAR FOR THE WEEKEND AND EARLY NEXT WEEK...WE SHOULD BR PRETTY DRY
BUT BREEZY ACROSS THE SOUTH AND SNAKE PLAIN. WE SLOWLY TRENDED THAT
DIRECTION WITH THE FORECAST WHERE IT WAS NEEDED...BUT NOT COMPLETELY
TO THAT END OF THE SPECTRUM. KEYES
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
358 PM CDT Mon Aug 18 2014
.SHORT TERM...(This Evening through Tuesday)
Issued at 352 PM CDT MON AUG 18 2014
The center of an upper level trough was located across eastern ND
late this afternoon with an upper level trough axis extending
southwest across central SD. The numerical models show this upper
level trough digging southeast across southern MN and eastern NE
into northern MO. The southwest section of the upper trough will
move southeast across northeast KS between 6Z and 12Z. The NAM,
GFS and ECMWF forecast QPF across northeast and east central KS
later Tonight, with the ECMWF and NAM showing most of the CWA with
QPF. The NAM model shows weak isentropic lift at the 310K level
with LFCs around 700mb. The most intense isentropic lift at the
310K level will be across northern MO and IA.
The mesoscale models, consisting of the ARW, NMM and HRRR do not
forecast any QPF across the CWA tonight. I will probably keep slight
chance to chance pops across much of the CWA, since the ascent ahead
of the H5 trough combined with isentropic lift should allow elevated
thunderstorms to develop across the northeast counties of the CWA
around midnight, then building southwest across the central and
southwest counties of the CWA through the early morning hours before
spreading southeast across much of east central KS by 12Z TUE.
Any lingering elevated thunderstorms, if they do develop, will shift
southeast of the CWA during the mid morning hours. Skies should
clear through the late morning and early afternoon hours and
temperatures will warm into the lower to mid 90s. If there is a
leftover outflow boundary across the northeast counties, then
temperatures along the NE border may only reach into the upper 80s.
I placed in 14 pops in case there is enough surface convergence for
an isolated thunderstorm during the afternoon hours.
.LONG TERM...(Tuesday Night through Monday)
Issued at 352 PM CDT MON AUG 18 2014
Models are in agreement that heights rises and resulting warm air
advection will be situated across the northeast corner of the county
warning area Tuesday evening providing another chance for
thunderstorms. As this area focuses further northward through the
night...have removed pops this area after midnight. Will keep lows
mild in the low to middle 70s. This will then set the stage for
mostly sunny very warm...breezy day on Wednesday. Highs will
generally be 95 to 100 degrees with the warmest in the Abilene area
and the coolest near Hiawatha.
As the upper ridge builds across the southern plains...expect dry
weather across the cwa Wednesday night through Thursday. However...
with south winds continuing...highs Thursday will again be in the
middle to upper 90s.
As the cutoff upper trough in the desert southwest gets picked up by
Thursday and heads into the central and northern high plains into
the weekend...there will be better chances for thunderstorms across
the area...although the northern/northwest 1/2 of the cwa will be
the more likely areas to see rain. Do not expect a frontal passage
until during the day Sunday...so may not see highs temps below 90
degrees until Monday when readings in the middle to upper 80s should
be the rule.
&&
.AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon)
Issued at 1237 PM CDT MON AUG 18 2014
Expect VFR conditions across the terminals through the next 24
hours. An isolated thunderstorm may affect the terminals between
6Z and 12Z TUE. At this time confidence is not high enough to
include in TAFS.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...63
AVIATION...Gargan
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
230 PM CDT Mon Aug 18 2014
...UPDATE TO LONG TERM...
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 1202 PM CDT MON AUG 18 2014
There is a high pressure ridge over Colorado south into New Mexico
late this afternoon. A lee side trough is near the Kansas and
Colorado border, and a warm front has been pushing northeast
through western Kansas this morning. The forecast is on track for
today, with highs just over 100F degrees likely somewhere across
southern and western Kansas, and upper 90s in our northern zones.
There could be a few and far between showers and isolated
thunderstorms just about anywhere late today. The HRRR model shows
a few thunderstorms across our south and southeast zones after
21z, but the NAM and NAMNG5 models are showing storms first over
our west and then moving across the northern CWA. Mid and high
clouds will be on the increase late this afternoon and evening.
So, the low Pops in the 17-20 percent range blanketing our
forecast area seem reasonable. Time will tell on which model is
more correct.
The same HRRR, NAM, and NAMNG5 models decrease the measurable
precip after 04Z, and then the clouds will slowly dissipate after
09Z or so. I plan to reduce 20 percent Pops rapidly between 06Z and
12Z. Not much precipitation will fall either, as any convection
will be high based. I used the QPF_from_PoP application, and it
only shows 0.01 to spotty 0.03 inches of rain overnight. With
clouds breaking late and perhaps a little rain, minimum temperatures
should end up in the middle 60s in Syracuse, Scott City, and
Wakeeney, while settling only to around 70F degrees in the Meade,
Coldwater and Medicine Lodge areas. Winds will continue to hover
at less than 10 MPH tonight.
On Tuesday, the surface low will advect into central Kansas, and the
front will sag south across part of our CWA. Thus, Max temps should
dip just a little north of the front, while south along the Oklahoma
border near Medicine Lodge, it should warm up to around 100F. Winds
on Tuesday will be breezy from the south in the 15 to 25 mph and
gusty range. I do not think there will any precipitation on
Tuesday, as the lower max temps will result in less instability than
today.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 225 PM CDT MON AUG 18 2014
Medium range models indicate an upper level ridge of high pressure
transitioning eastward out of the Western High Plains into the
Central Plains to begin the period Tuesday night. Combined with
a weak flow aloft, drier conditions are likely to prevail through
late Wednesday afternoon. Meanwhile, an upper level trough will dig
southeast across southern California Wednesday setting up a strong
southwest flow aloft across the Central and Southern Rockies,
including a +90kt jet core projected to lift northeast out of the
Desert Southwest into the Colorado Rockies. With a prevailing lee
side trough providing increased convergence in the lower levels,
thunderstorm development is likely across portions of eastern
Colorado Wednesday afternoon with a few storms potentially
drifting into western Kansas later in the evening through early
Thursday. However, the weaker flow aloft across western Kansas
will limit the strength and coverage of any storms. The upper
level shortwave will then lift northeast going into the weekend
while a large scale upper level high remains locked in across the
Deep South. Although precip chances will remain present virtually
each day into the weekend, the weaker flow aloft will limit storm
development, strength, and coverage.
Temperatures will remain above normal Wednesday as the
aforementioned upper level ridge shifts east across the Central
Plains. A prevailing southerly flow across western Kansas will
reinforce the warmer air mass already in place across the region
with H85 temperatures ranging from the upper 20s(C) in central
Kansas to around 30C closer to the Colorado border. As lower level
lapse rates steepen into the afternoon, look for highs well up
into the 90s(F) to near 100F Wednesday. Similar temperatures are
then expected each day through Saturday as the low level southerly
flow persists into the early part of the weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1137 AM CDT MON AUG 18 2014
With building high pressure from the west and weak high pressure
aloft centered southwest of Kansas, there will very few clouds
overhead and light surface winds through the next 24 hours. There
will be just enough instability for a few showers and isolated
thunderstorms late this afternoon and overnight, but there is not
enough confidence to put convection into the TAFS. VFR conditions
should dominate for most of this TAF period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 69 97 71 99 / 20 10 0 10
GCK 67 96 70 98 / 30 10 0 10
EHA 66 95 68 98 / 20 10 0 20
LBL 66 96 71 98 / 20 10 0 10
HYS 68 98 71 99 / 20 10 0 10
P28 70 98 74 99 / 20 10 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Burke
LONG TERM...JJohnson
AVIATION...Burke
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
100 PM CDT Mon Aug 18 2014
...Updated for the short term discussion...
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 1202 PM CDT MON AUG 18 2014
There is a high pressure ridge over Colorado south into New Mexico
late this afternoon. A lee side trough is near the Kansas and
Colorado border, and a warm front has been pushing northeast
through western Kansas this morning. The forecast is on track for
today, with highs just over 100F degrees likely somewhere across
southern and western Kansas, and upper 90s in our northern zones.
There could be a few and far between showers and isolated
thunderstorms just about anywhere late today. The HRRR model shows
a few thunderstorms across our south and southeast zones after
21z, but the NAM and NAMNG5 models are showing storms first over
our west and then moving across the northern CWA. Mid and high
clouds will be on the increase late this afternoon and evening.
So, the low Pops in the 17-20 percent range blanketing our
forecast area seem reasonable. Time will tell on which model is
more correct.
The same HRRR, NAM, and NAMNG5 models decrease the measurable
precip after 04Z, and then the clouds will slowly dissipate after
09Z or so. I plan to reduce 20 percent Pops rapidly between 06Z and
12Z. Not much precipitation will fall either, as any convection
will be high based. I used the QPF_from_PoP application, and it
only shows 0.01 to spotty 0.03 inches of rain overnight. With
clouds breaking late and perhaps a little rain, minimum temperatures
should end up in the middle 60s in Syracuse, Scott City, and
Wakeeney, while settling only to around 70F degrees in the Meade,
Coldwater and Medicine Lodge areas. Winds will continue to hover
at less than 10 MPH tonight.
On Tuesday, the surface low will advect into central Kansas, and the
front will sag south across part of our CWA. Thus, Max temps should
dip just a little north of the front, while south along the Oklahoma
border near Medicine Lodge, it should warm up to around 100F. Winds
on Tuesday will be breezy from the south in the 15 to 25 mph and
gusty range. I do not think there will any precipitation on
Tuesday, as the lower max temps will result in less instability than
today.
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 358 AM CDT MON AUG 18 2014
Upper level troughing will gradually build across the northwestern
United States trough Friday, with upper level ridging across the
southern Plains. This pattern is conducive to weak lee troughing
over the high plains and mainly hot and dry weather across
southwestern Kansas. High temperatures will generally be between 96
and 100F each day, with lows from the upper 60s in far western
Kansas to the mid 70s farther east. There are small chances for
thunderstorms somewhere across western Kansas just about every day
from Wednesday to Friday ahead of the lee trough. The best chance
of severe thunderstorms will be to the northeast of southwest
Kansas where rich low level moisture will reside. However,
damaging wind gusts can not be ruled out this time of year when
it gets hot, with high dewpoint depressions.
There is some disagreement as to the arrival of the upper level
trough as it approaches the central and northern plains sometime
between Saturday night and Monday. The GFS/GEM/UKMET are faster
while the ECMWF is quite a bit slower. A faster solution would
result in better chances for thunderstorms as early as late Saturday
while the slower solution would delay the more widespread
thunderstorm activity until late Sunday. The cold front arrival
also hinges on the speed of the system, with cooler weather arriving
either Sunday or Monday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1137 AM CDT MON AUG 18 2014
With building high pressure from the west and weak high pressure
aloft centered southwest of Kansas, there will very few clouds
overhead and light surface winds through the next 24 hours. There
will be just enough instability for a few showers and isolated
thunderstorms late this afternoon and overnight, but there is not
enough confidence to put convection into the TAFS. VFR conditions
should dominate for most of this TAF period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 100 69 97 72 / 20 20 10 10
GCK 99 67 96 71 / 20 30 10 10
EHA 99 66 95 69 / 20 20 10 10
LBL 100 66 96 72 / 20 20 10 10
HYS 98 68 98 72 / 20 20 10 10
P28 100 70 98 75 / 20 20 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Burke
LONG TERM...Finch
AVIATION...Burke
AREA FORECAST DISCUSSION
NWS JACKSON KY
702 PM EDT MON AUG 18 2014
.UPDATE...
ISSUED AT 702 PM EDT MON AUG 18 2014
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. THE PRECIPITATION HAS BEEN TAPERING OFF AS THE SHORT WAVE
MOVES OFF TO THE EAST. LOWERED THE PROBABILITY OF PRECIPITATION
BASED ON CURRENT RADAR AND THE LATEST HRRR OUTPUT. ALSO TOOK OUT THE
CHANCE OF THUNDER OUT AS NONE HAS DEVELOPED ALL DAY AND THE MODELS
ARE NOT SUPPORTING THEIR DEVELOPMENT IN THE NEAR TERM. THE ONLY
THUNDER IS CURRENTLY OVER CENTRAL TENNESSEE. A WEAK FRONT IS STILL
QUASI STATIONARY OVER THE AREA. EXPECT TO SEE SOME FAIRLY DENSE FOG
TONIGHT...ESPECIALLY IN THE VALLEYS.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 255 PM EDT MON AUG 18 2014
THE LOW PRESSURE SYSTEM THAT BROUGHT THE WIDESPREAD RAIN LAST NIGHT
INTO THIS MORNING HAS MOVED INTO WV...TAKING THE DEEPER MOISTURE AND
BETTER LIFT WITH IT. A WEST EAST ORIENTED QUASI STATIONARY FRONT
REMAINS ACROSS KENTUCKY...AND SCATTERED LIGHT SHOWERS CONTINUE TO
MOVE FROM WEST TO EAST ACROSS THE AREA. ANOTHER WAVE OF LOW PRESSURE
EVIDENT ON SATELLITE AND RADAR IMAGERY WAS MOVING EAST ALONG THE TN MS
BORDER. THIS FEATURE...ALONG WITH THE BOUNDARY ACROSS KY WILL
NECESSITATE CONTINUING WITH A CHANCE OF RAIN OVERNIGHT. HOWEVER THE
BEST RAIN AND THUNDER CHANCES SHOULD BE SOUTH OF KY TONIGHT.
WITH VERY MOIST BOUNDARY LAYER AND SOME BREAKS EXPECTED IN THE CLOUDS
THIS EVENING...FOG AND LOW CLOUDS ARE EXPECTED TO DEVELOP DURING THE
NIGHT AND LINGER INTO THE MORNING ON TUESDAY. WILL INCLUDE FOG IN THE
FORECAST FOR TONIGHT. ON TUESDAY THE NEXT SHORT WAVE IN THIS VERY
ACTIVE PATTERN WILL BE PUSHING INTO THE WESTERN GREAT LAKES REGION. AT
THE SURFACE A VERY MOIST AND WARM AIR MASS WILL REMAIN IN PLACE
ACROSS EASTERN KY ON TUESDAY...WHILE A COLD FRONT DROPS SOUTHEAST ACROSS IL
AND INDIANA. THUNDERSTORMS ARE EXPECTED TO DEVELOP AHEAD OF THIS
FRONT TUESDAY AFTERNOON. CURRENT THINKING IS THAT SHOWERS AND
THUNDERSTORMS THAT DEVELOP TO OUR NORTHWEST ON TUESDAY WILL MOVE INTO
OUR AREA TUESDAY NIGHT. WITH THIS THOUGHT IN MIND WILL INTRODUCE
LIKELY PROBABILITIES FOR SHOWERS AND THUNDERSTORMS IN THE NORTHERN
PART OF OUR FORECAST AREA TUESDAY NIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 255 PM EDT MON AUG 18 2014
MODELS CONTINUE TO DISPLAY GOOD AGREEMENT THROUGH THE EXTENDED.
UPPER/MID LEVEL GREAT LAKES LOW WILL MAKE A BEE LINE TO THE MID
ATLANTIC COAST BY FRIDAY. MEANWHILE BURGEONING RIDGE TO OUR WEST
WILL EXERT ITS INFLUENCE FROM THE SOUTHERN PLAINS/MISSISSIPPI RIVER
DELTA NORTHWARD INTO THE UPPER MIDWEST. GREAT LAKES LOW WILL PASS TO
OUR NORTHEAST DURING ITS MARCH TO THE COAST AND DRAG A SURFACE
FRONTAL BOUNDARY ACROSS THE CENTER OF THE OHIO VALLEY REGION.
SHARPENING UPPER LEVEL RIDGE AXIS WILL SHIFT SOUTHEASTWARD OVER OUR
AREA TOWARDS THE END OF THE EXTENDED AS ENERGY ROUNDS ITS TOP ACROSS
THE NORTHERN TIER. DESPITE THE BUILDING RIDGE ALOFT...THE BY THEN
QUASI-STATIONARY SFC FRONTAL BOUNDARY WILL REMAIN IN OUR VICINITY AS
IT BECOMES ORIENTED PARALLEL TO THE UPPER LEVEL FLOW PATTERN. THUS
WITH LITTLE TO NO FORCING AT THE MID AND UPPER LEVELS...THIS
BOUNDARY WILL REMAIN CLOSE ENOUGH TO OUR AREA TO SERVE AS A FOCUS
FOR ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY THROUGH THE LATTER
HALF OF THE EXTENDED PERIOD. THE MAINLY DIURNAL SHOWER AND
THUNDERSTORM ACTIVITY MAY BE AUGMENTED BY ONE OR TWO ORGANIZED
THUNDERSTORM COMPLEXES DROPPING DOWN FROM THE NORTHWEST ON THE EAST
SIDE OF THE UPPER RIDGE.
FOR SENSIBLE WEATHER...WE WILL SEE THE RETURN OF TRUE SUMMER LIKE
WEATHER AS RIDGING TO OUR SOUTHWEST WILL BE STRONG ENOUGH TO SEND
TEMPERATURES INTO AND ABOVE SEASONABLE NORMS DESPITE THE INCREASED
HUMIDITY. THIS WILL ALSO HELP TO ENHANCE THE DIURNALLY DRIVEN
INSTABILITY ACROSS THE AREA RESULTING IN THE BEST CHANCES OF STORMS
EACH AFTERNOON AND EVENING. THE THREAT OF RAIN DECREASES BY NEXT
WEEKEND AS THE UPPER RIDGE AMPLIFIES AND SHIFTS EASTWARD A BIT...BUT
THE POTENTIAL CAN NOT BE TOTALLY REMOVED. IN ADDITION...SHOULD THE
RIDGE EXERT A STRONGER INFLUENCE BY SHIFTING JUST A BIT MORE EAST WE
MAY BE IN FOR EVEN HOTTER WEATHER BY NEXT WEEKEND. WITH THE 0Z ECMWF
ADVERTISING H850 TEMPS UP AROUND 22C TO 24C...THE POSSIBLY EXISTS
THAT WE MIGHT SEE SOME OF OUR HOTTEST WEATHER OF THE SUMMER THUS
FAR.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 702 PM EDT MON AUG 18 2014
A WIDE VARIETY OF CONDITIONS CAN BE EXPECTED ACROSS EASTERN KENTUCKY
FOR THE REMAINDER OF THE EARLY EVENING. AS THERE IS SOME CLEARING
THIS EVENING...EXPECT TO SEE SOME DENSE FOG FORMING IN THE VALLEYS
AS WELL AS THE TAF STATIONS WITH VLIFR AND IFR CONDITIONS
PREDOMINATING. THE FOG WILL MOST LIKELY TAKE UNTIL 14-15Z TO FINALLY
BURN OFF. EXPECTING SOME SCATTERED SHOWERS AND THUNDERSTORMS TOMORROW
ACROSS THE AREA. EXPECT THE ACTIVITY TO PICK UP IN THE LATE AFTERNOON
AND EVENING. WILL MOST LIKELY NOT SEE MUCH VFR TOMORROW UNTIL THE
AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JJ
SHORT TERM...SBH
LONG TERM...RAY
AVIATION...JJ
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1248 PM CDT MON AUG 18 2014
.AVIATION...
FOR THE 18/18Z TAFS...EARLIER ROUND OF CONVECTION HAS EXITED THE
AREA BUT A FEW SCT SHWRS CONTINUE TO DEVELOP ALONG A SHEAR AXIS
ORIENTED ROUGHLY ALONG THE I-20 CORRIDOR. COVERAGE IS SPOTTY BUT
WILL MAINTAIN VCSH AT THE I-20 TERMINALS UNTIL EARLY THIS EVENING
WHEN THE SHWRS ARE EXPECTED TO DISSIPATE. LOW CLOUDS AND FOG
SHOULD DEVELOP ACROSS MOST OF THE AREA AFTER 19/08Z WITH
CONDITIONS GRADUALLY IMPROVING BY MID MORNING TUESDAY. /09/
&&
.PREV DISCUSSION... /ISSUED 1145 AM CDT MON AUG 18 2014/
DISCUSSION...
LATE THIS MORNING THE UPPER LEVEL DISTURBANCE HAS SHIFTED EAST INTO
EASTERN ARKANSAS AND ALONG THE MISSISSIPPI RIVER AND CONTINUED TO
PRODUCE SHOWERS AND THUNDERSTORMS OVER PARTS OF ARKANSAS AND
NORTHEAST LOUISIANA. THE UPPER LEVEL SHEAR AXIS THAT HAS BEEN OVER
THE FOUR STATE REGION FOR THE PAST FEW DAYS HAS SHIFTED TO THE
SOUTH AND EXTENDED ACROSS PARTS OF CENTRAL MISSISSIPPI AND ACROSS
LOWER PARTS OF NORTHWEST AND NORTH CENTRAL LOUISIANA AND EAST TEXAS.
THIS AREA AND SOUTH WILL BE WHERE EXPECTED RAIN CHANCES WILL BE LATER
THE REST OF TODAY. ANOTHER UPPER DISTURBANCE WAS MOVING ACROSS NORTHEAST
OKLAHOMA...AND WAS PRODUCING SHOWERS AND THUNDERSTORMS. THE SYSTEM
WILL MOVE INTO WESTERN ARKANSAS AND MAY AFFECT PARTS OF SOUTHWEST AND
SOUTH CENTRAL ARKANSAS LATER THIS AFTERNOON AND OVERNIGHT. MADE
ADJUSTMENT IN THE RAIN CHANCES FOR TODAY AND TONIGHT BASED ON THE
CURRENT TRENDS AND FORECAST TRACK AND LOCATIONS OF THE UPPER SYSTEMS.
/06/
PREV DISCUSSION... /ISSUED 443 AM CDT MON AUG 18 2014/
DISCUSSION...
CONVECTION OVER SW AR HAS RAPIDLY DEVELOPED ON THE ERN PERIPHERY
OF AN MCV...WHERE RADAR AND SATELLITE INDICATE TO BE CENTERED NEAR
DEQ AS OF 09Z. LOCALLY HEAVY RAINFALL HAS BEEN EVIDENT PER
REFLECTIVITY IMAGERY...WHERE PERSISTENT TRAINING OF CONVECTION HAS
RESULTED IN WIDESPREAD 2-4 INCH RAINFALL TOTALS...PER DUAL POL
ESTIMATES. THE 00Z WRF HAS AGAIN INITIALIZED WELL THIS
MORNING WITH THE POSITION AND SLOWER MOVEMENT OF THE MCV...WITH THE
GFS CONTINUING TO SUFFER FROM FEEDBACK PROBLEMS AND SHOWS A MUCH
MORE RAPID PROGRESSION OF THE MCV ACROSS SW AR /EXITING THE AREA SHORTLY
AFTER 12Z/. MEANWHILE...THE LATEST HRRR IS OUT TO LUNCH AND DOES
NOT EVEN ACKNOWLEDGE THE CURRENT CONVECTION BUT DOES SUGGEST SCT
DEVELOPMENT LATER THIS MORNING CONTINUING THROUGH THE AFTERNOON
NEAR THE PARENT UPPER SHEAR AXIS OVER EXTREME NRN LA. THE CURRENT
HEAVY RAINFALL AXIS LINES UP WELL WITH A TONGUE OF GREATER SFC
THETA-E AND SBCAPES...WHICH RANGE FROM 1000-1500 J/KG AS OF 09Z.
THIS SHOULD CONTINUE TO FAVOR A SHORT TERM HEAVY RAINFALL THREAT
THIS MORNING OVER SW AR...AS THE MCV DRIFTS SLOWLY E THIS MORNING.
HAVE SEEN SCT CONVECTION DEVELOP FARTHER S ACROSS NRN
CADDO/BOSSIER/WEBSTER PARISHES AS WELL BENEATH THE MCV WHERE
850-700MB THETA-E RIDGING SHOULD RESULT IN CONVECTION EXPANDING E
ALONG/N OF THE I-20 CORRIDOR THROUGH MIDDAY. GIVEN THESE
OBSERVATIONS AND THE FACT THAT PW/S SHOULD RANGE FROM 2-2.25
INCHES...HAVE INCREASED POPS TO LIKELY THIS MORNING AND ADDED
HEAVY RAINFALL WORDING ACROSS MUCH OF SW AR...AND HAVE MAINTAINED
MID TO HIGH CHANCE POPS FARTHER S ACROSS NCNTRL LA AS THE MCV
SHIFTS E TO THE MS RIVER BY MIDDAY...AND ITS ATTENDANT SHEAR AXIS
DRIFTS ESE ACROSS THE AREA. THE AFTERNOON SEABREEZE SHOULD BE LESS
OF A FACTOR THIS AFTERNOON OVER DEEP E TX AS 850MB WINDS REMAIN
WSW BENEATH THE SHEAR AXIS...THUS SLIGHT CHANCE POPS SHOULD
SUFFICE FOR THESE AREAS. MAX TEMPS TODAY WILL AGAIN BE A TOUGH
CALL...BUT HAVE LOWERED TEMPS SLIGHTLY TO NEAR 90S OVER SCNTRL
AR/NCNTRL LA...WITH MID 90S EXPECTED ELSEWHERE AS THE AC CANOPY
BENEATH THE MCV GRADUALLY ERODES AND GIVES WAY TO SUNSHINE THIS
AFTERNOON.
THE WRF DOES SUGGEST A WEAK REFLECTION OF THE SHEAR AXIS REMAINING
IN PLACE ACROSS N LA/DEEP E TX THIS EVENING...AND THUS HAVE
MAINTAINED SLIGHT CHANCE POPS FOR THESE AREAS. AFTERWARDS...FLAT
500MB RIDGING IS EXPECTED TO SHIFT E INTO THE SRN PLAINS TUESDAY
FROM THE SRN ROCKIES...WITH A WEAK SEABREEZE POSSIBLE ACROSS DEEP
E TX/SRN SECTIONS OF NCNTRL LA DURING THE AFTERNOON AND EARLY
EVENING. UPPER RIDGING OVER THE WRN ATLANTIC AND ERN GULF REMAINS
PROGGED TO EXPAND FARTHER WNW WHILE ABSORBING THE 500MB RIDGE
CENTER OVER THE LOWER MS VALLEY WEDNESDAY...BEFORE CENTERING
ITSELF OVER THE MID-SOUTH REGION/LOWER MS VALLEY THURSDAY. STILL
SHOULD SEE A COUPLE MORE DAYS OF WEAK SEABREEZE CONVECTION ACROSS
OUR SRN ZONES WEDNESDAY AND THURSDAY...BEFORE LARGE SCALE
SUBSIDENCE BENEATH THE RIDGE INCREASES AS THE RIDGE CENTER BECOMES
POSITIONED OVER THE REGION.
PERSISTENCE WILL DOMINATE LATE THIS WEEK THROUGH THE REMAINDER OF
THE EXTENDED...WITH MAX TEMPS IN THE MID/UPPER 90S EACH DAY. STILL
CAN/T RULE OUT TRIPLE DIGIT HEAT OCCURRING LATE THIS WEEK THROUGH
EARLY NEXT WEEKEND ESPECIALLY OVER E TX/PORTIONS OF NW LA...WHICH
HAVE BEEN MOSTLY VOID OF WETTING RAINFALL THE LAST FEW WEEKS AND
WILL APPEAR TO MISS MUCH OF THE CONVECTION THIS MORNING. BOTH THE
GFS/ECMWF DO SUGGEST THAT THE RIDGE CENTER MAY SHIFT A TAD FARTHER
E INTO THE SE STATES BY MIDWEEK NEXT WEEK...ALLOWING WEAKNESSES
BENEATH THE RIDGE TO RETROGRADE W AND POSSIBLY ALLOW FOR ISOLATED
CONVECTION OVER THE SRN ZONES AS WE ENTER THE FINAL FEW DAYS OF
AUGUST.
PRELIMS TO FOLLOW BELOW...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 75 96 75 96 75 / 10 10 10 10 10
MLU 74 95 74 95 74 / 20 10 10 10 10
DEQ 71 95 72 95 73 / 0 10 0 0 0
TXK 74 95 74 96 74 / 10 10 0 0 0
ELD 73 95 73 96 74 / 20 10 0 0 0
TYR 75 96 75 96 75 / 10 10 10 10 10
GGG 74 96 74 96 75 / 10 10 10 10 10
LFK 76 97 76 96 76 / 20 20 10 20 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1145 AM CDT MON AUG 18 2014
.DISCUSSION...
LATE THIS MORNING THE UPPER LEVEL DISTURBANCE HAS SHIFTED EAST INTO
EASTERN ARKANSAS AND ALONG THE MISSISSIPPI RIVER AND CONTINUED TO
PRODUCE SHOWERS AND THUNDERSTORMS OVER PARTS OF ARKANSAS AND
NORTHEAST LOUISIANA. THE UPPER LEVEL SHEAR AXIS THAT HAS BEEN OVER
THE FOUR STATE REGION FOR THE PAST FEW DAYS HAS SHIFTED TO THE
SOUTH AND EXTENDED ACROSS PARTS OF CENTRAL MISSISSIPPI AND ACROSS
LOWER PARTS OF NORTHWEST AND NORTH CENTRAL LOUISIANA AND EAST TEXAS.
THIS AREA AND SOUTH WILL BE WHERE EXPECTED RAIN CHANCES WILL BE LATER
THE REST OF TODAY. ANOTHER UPPER DISTURBANCE WAS MOVING ACROSS NORTHEAST
OKLAHOMA...AND WAS PRODUCING SHOWERS AND THUNDERSTORMS. THE SYSTEM
WILL MOVE INTO WESTERN ARKANSAS AND MAY AFFECT PARTS OF SOUTHWEST AND
SOUTH CENTRAL ARKANSAS LATER THIS AFTERNOON AND OVERNIGHT. MADE
ADJUSTMENT IN THE RAIN CHANCES FOR TODAY AND TONIGHT BASED ON THE
CURRENT TRENDS AND FORECAST TRACK AND LOCATIONS OF THE UPPER SYSTEMS.
/06/
&&
.PREV DISCUSSION... /ISSUED 529 AM CDT MON AUG 18 2014/
AVIATION...
CLUSTER OF INTENSE TSTMS SLOWLY SHIFTING EAST ACROSS SW AR...MOVG
EAST OF KTXK TERMINAL...BUT NOW MOVG INTO KELD TERMINAL. STEEP
LAPSE RATES KEEPING MOST CLOUD BASES IN VFR...EVEN NEAR STORMS.
OUTFLOW BOUNDARIES MAY REGENERATE MIDDAY STORMS OVER KMLU AND
POSSIBLY KSHV TERMINALS...LESS CONVECTIVE ACTIVITY OVER NE TX EXPECTED.
HOWEVER...MID LVL DECKS WITH LGT RAIN MOVG EAST TOWARDS KTYR AND
KGGG. SW WINDS NEAR 10 KTS ACROSS MUCH OF AREA...MAINLY BTWN 18/15-21Z
TODAY...EXCEPT POSSIBLE GUSTS NEAR CONVECTION. ALSO...PATCHY FOG
POSSIBLE OVERNIGHT...MAINLY WHERE HEAVY RAIN FELL AT KTXK AND
KELD./VII/.
PREV DISCUSSION... /ISSUED 443 AM CDT MON AUG 18 2014/
DISCUSSION...
CONVECTION OVER SW AR HAS RAPIDLY DEVELOPED ON THE ERN PERIPHERY
OF AN MCV...WHERE RADAR AND SATELLITE INDICATE TO BE CENTERED NEAR
DEQ AS OF 09Z. LOCALLY HEAVY RAINFALL HAS BEEN EVIDENT PER
REFLECTIVITY IMAGERY...WHERE PERSISTENT TRAINING OF CONVECTION HAS
RESULTED IN WIDESPREAD 2-4 INCH RAINFALL TOTALS...PER DUAL POL
ESTIMATES. THE 00Z WRF HAS AGAIN INITIALIZED WELL THIS
MORNING WITH THE POSITION AND SLOWER MOVEMENT OF THE MCV...WITH THE
GFS CONTINUING TO SUFFER FROM FEEDBACK PROBLEMS AND SHOWS A MUCH
MORE RAPID PROGRESSION OF THE MCV ACROSS SW AR /EXITING THE AREA SHORTLY
AFTER 12Z/. MEANWHILE...THE LATEST HRRR IS OUT TO LUNCH AND DOES
NOT EVEN ACKNOWLEDGE THE CURRENT CONVECTION BUT DOES SUGGEST SCT
DEVELOPMENT LATER THIS MORNING CONTINUING THROUGH THE AFTERNOON
NEAR THE PARENT UPPER SHEAR AXIS OVER EXTREME NRN LA. THE CURRENT
HEAVY RAINFALL AXIS LINES UP WELL WITH A TONGUE OF GREATER SFC
THETA-E AND SBCAPES...WHICH RANGE FROM 1000-1500 J/KG AS OF 09Z.
THIS SHOULD CONTINUE TO FAVOR A SHORT TERM HEAVY RAINFALL THREAT
THIS MORNING OVER SW AR...AS THE MCV DRIFTS SLOWLY E THIS MORNING.
HAVE SEEN SCT CONVECTION DEVELOP FARTHER S ACROSS NRN
CADDO/BOSSIER/WEBSTER PARISHES AS WELL BENEATH THE MCV WHERE
850-700MB THETA-E RIDGING SHOULD RESULT IN CONVECTION EXPANDING E
ALONG/N OF THE I-20 CORRIDOR THROUGH MIDDAY. GIVEN THESE
OBSERVATIONS AND THE FACT THAT PW/S SHOULD RANGE FROM 2-2.25
INCHES...HAVE INCREASED POPS TO LIKELY THIS MORNING AND ADDED
HEAVY RAINFALL WORDING ACROSS MUCH OF SW AR...AND HAVE MAINTAINED
MID TO HIGH CHANCE POPS FARTHER S ACROSS NCNTRL LA AS THE MCV
SHIFTS E TO THE MS RIVER BY MIDDAY...AND ITS ATTENDANT SHEAR AXIS
DRIFTS ESE ACROSS THE AREA. THE AFTERNOON SEABREEZE SHOULD BE LESS
OF A FACTOR THIS AFTERNOON OVER DEEP E TX AS 850MB WINDS REMAIN
WSW BENEATH THE SHEAR AXIS...THUS SLIGHT CHANCE POPS SHOULD
SUFFICE FOR THESE AREAS. MAX TEMPS TODAY WILL AGAIN BE A TOUGH
CALL...BUT HAVE LOWERED TEMPS SLIGHTLY TO NEAR 90S OVER SCNTRL
AR/NCNTRL LA...WITH MID 90S EXPECTED ELSEWHERE AS THE AC CANOPY
BENEATH THE MCV GRADUALLY ERODES AND GIVES WAY TO SUNSHINE THIS
AFTERNOON.
THE WRF DOES SUGGEST A WEAK REFLECTION OF THE SHEAR AXIS REMAINING
IN PLACE ACROSS N LA/DEEP E TX THIS EVENING...AND THUS HAVE
MAINTAINED SLIGHT CHANCE POPS FOR THESE AREAS. AFTERWARDS...FLAT
500MB RIDGING IS EXPECTED TO SHIFT E INTO THE SRN PLAINS TUESDAY
FROM THE SRN ROCKIES...WITH A WEAK SEABREEZE POSSIBLE ACROSS DEEP
E TX/SRN SECTIONS OF NCNTRL LA DURING THE AFTERNOON AND EARLY
EVENING. UPPER RIDGING OVER THE WRN ATLANTIC AND ERN GULF REMAINS
PROGGED TO EXPAND FARTHER WNW WHILE ABSORBING THE 500MB RIDGE
CENTER OVER THE LOWER MS VALLEY WEDNESDAY...BEFORE CENTERING
ITSELF OVER THE MID-SOUTH REGION/LOWER MS VALLEY THURSDAY. STILL
SHOULD SEE A COUPLE MORE DAYS OF WEAK SEABREEZE CONVECTION ACROSS
OUR SRN ZONES WEDNESDAY AND THURSDAY...BEFORE LARGE SCALE
SUBSIDENCE BENEATH THE RIDGE INCREASES AS THE RIDGE CENTER BECOMES
POSITIONED OVER THE REGION.
PERSISTENCE WILL DOMINATE LATE THIS WEEK THROUGH THE REMAINDER OF
THE EXTENDED...WITH MAX TEMPS IN THE MID/UPPER 90S EACH DAY. STILL
CAN/T RULE OUT TRIPLE DIGIT HEAT OCCURRING LATE THIS WEEK THROUGH
EARLY NEXT WEEKEND ESPECIALLY OVER E TX/PORTIONS OF NW LA...WHICH
HAVE BEEN MOSTLY VOID OF WETTING RAINFALL THE LAST FEW WEEKS AND
WILL APPEAR TO MISS MUCH OF THE CONVECTION THIS MORNING. BOTH THE
GFS/ECMWF DO SUGGEST THAT THE RIDGE CENTER MAY SHIFT A TAD FARTHER
E INTO THE SE STATES BY MIDWEEK NEXT WEEK...ALLOWING WEAKNESSES
BENEATH THE RIDGE TO RETROGRADE W AND POSSIBLY ALLOW FOR ISOLATED
CONVECTION OVER THE SRN ZONES AS WE ENTER THE FINAL FEW DAYS OF
AUGUST.
PRELIMS TO FOLLOW BELOW...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 94 75 96 75 96 / 20 10 10 10 10
MLU 90 74 95 74 95 / 50 20 10 10 10
DEQ 93 71 95 72 95 / 20 0 10 0 0
TXK 93 74 95 74 96 / 20 10 10 0 0
ELD 91 73 95 73 96 / 30 20 10 0 0
TYR 95 75 96 75 96 / 20 10 10 10 10
GGG 94 74 96 74 96 / 20 10 10 10 10
LFK 96 76 97 76 96 / 40 20 20 10 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
06
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
645 PM EDT MON AUG 18 2014
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL DEVELOP OVER VIRGINIA TONIGHT BEFORE
MOVING OFF THE COAST TUESDAY. WEAK HIGH PRESSURE RETURNS ON
WEDNESDAY BEFORE ANOTHER SYSTEM OVER THE GREAT LAKES MOVES INTO
THE MID ATLANTIC STATES FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE THIS EVENING TO DROP THE WATCH AND TWEAK THE POPS SOME
OVERNIGHT. AS SECONDARY LOW DEVELOPING OVER CENTRAL NC SHOULD
BECOME THE DOMINANT LOW OVERNIGHT LIFTING NORTHEAST INTO NORTHEAST
NC AND SOUTHEAST VA AND LOWER BAY. TRENDING TOWARDS THE HRRR POP
TRENDS WITH THE MOST WIDESPREAD SHOWERS AND STORMS ACROSS THE
SOUTHERN TWO THIRDS OF THE FORECAST AREA. EXPECT SCATTERED SHOWERS
AND STORMS WELL NORTH AND NORTHWEST OF RIC.
ONCE THE LOW BEGINS TO DEVELOP THIS EVENING...EXPECT TO SEE MORE
SHOWERS AND AREAS OF RAIN FORM ALONG AN NORTH OF THE FRONT WITH
MORE CONVECTIVE PRECIPITATION TO THE SOUTH OF IT. SOME AREAS COULD SEE
0.50 - 1 INCH OF RAIN AS PW CONTINUE TO RUN A LITTLE OVER 2 INCHES
IN A VERY MOIST ATMOSPHERE. HAVE ALSO BUMPED UP OVERNIGHT LOWS DUE
TO THE MORE HUMID AIRMASS.
FOR TUESDAY...THE LOW SLOWLY SLIDES OFF THE VA COAST AND HAS SOME
WRAP AROUND MOISTURE SO HAVE HELD ON TO THE PCPN A LITTLE LONGER
ACROSS THE DELMARVA AS THE 12Z NAM IS SLOWER THAN THE 12Z GFS IN
PULLING THE LOW OUT. LATER IN THE AFTERNOON...WILL GET THE SFC
BOUNDARY SLIDING DOWN INTO THE TIDEWATER AND NE NC SO MORE SHOWERS
ARE POSSIBLE THERE. FOR TEMPERATURES HAVE LEAN A LITTLE LOW
ESPECIALLY TOWARD THE NORTH THINKING THAT CLOUDS WILL LINGER AND
LIMIT THE DAY TIME HEATING.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
FROM TUESDAY NIGHT THROUGH THURSDAY...THE MODELS ARE SHOWING LOTS
OF VARIABLIITY WITH THE MOVEMENT OF SHORTWAVE ENERGY IN THE
NORTHWEST FLOW AS THE UPPER RIDGE OVER THE MS VALLEY BUILDS AND
THE UPPER LOW OVER THE GREAT LAKES IS SLOW TO MOVE EAST. WEDNESDAY
LOOKS TO BE THE DRIER OF THE TWO DAY AS THE EXITING LOW OFF THE
COAST ALLOWS FOR WEAK HIGH PRESSURE OVER THE NE TO NOSE SOUTHWARD
INTO THE MID ATLANTIC STATES AND THE MOISTURE LESSENS. BUT BY
THURSDAY...THE NW FLOW IS MORE ESTABLISHED AND WITH CONVECTION TO
THE NORTHWEST AND THE REGION IN A GOOD POSITION ON THE EDGE OF THE
RIDGE...COULD EASILY SEE CONVECTION DROP SE INTO THE REGION. SO
HAVE VERY LITTLE PCPN ON WEDNESDAY WITH HIGHER CHANCE POPS ON
THURSDAY. BUT CONFIDENCE IN THE OVER PATTERN IS LOW DUE TO THE
MODEL UNCERTAINTY FROM RUN TO RUN.
FOR TEMPERATURES...HAVE ALLOWED FOR SOME ADDITIONAL HEATING ON WED
AND THU DUE TO MORE SUNSHINE AND ALSO DUE TO THE WEST/NW FLOW
ALOFT.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
UNSETTLED WEATHER PATTERN CONTINUES INTO THE EXTENDED PERIOD AS NWLY
FLOW ALOFT DEVELOPS. TEMPS WILL BE NEAR TO SLIGHTLY BELOW
SEASONABLE...LATE SUMMER NORMS.
WHILE MEDIUM RANGE GUIDANCE CONTINUES TO STRUGGLE HANDLING THE
SPLIT/BLOCKY FLOW OVER THE HIGHER LATITUDES...MODELS HAVE BECOME
MORE STABLE WITH RESOLVING SRN STREAM ENERGY OVER THE OH VALLEY AND
MID-ATLANTIC REGION. THIS THANKS TO UPPER/SFC HIGH PRESSURE FROM THE
SE STATES EWD OFF THE COAST. WITH THAT SAID...FLOW AMPLIFIES OVER
THE ERN CONUS AS MID LEVEL HIGH PRESSURE BUILDS OVER THE CNTRL US
AND LOW PRESSURE REMAINS OVER THE NE US. THIS WILL PLACE THE
MID-ATLANTIC STATES IN NWLY FLOW ALOFT...OPENING THE DOOR FOR
SHORTWAVE ENERGY IN THE UPPER FLOW. QUASI-STATIONARY BOUNDARY WILL
LOCATE OVER THE REGION...JUST TO THE SOUTH. MOISTURE WILL NOT BE A
LIMITATION WITH PWATS PROGGED AROUND 2 INCHES (+1 STD DEV) AND
DEWPOINTS IN THE MID-UPPER 60S. ANTICIPATE A DIURNAL TREND WITH
SHOWERS/THUNDERSTORMS...BUT UPSTREAM MCS DEVELOPMENT MAY SPILL INTO
THE REGION DURING THE OVERNIGHT HOURS THRU THE WEEKEND. HIGHER POPS
MAY BE WARRANTED...BUT BASED ON THE DEGREE OF UNCERTAINTY AND
TIMING...WILL STICK MORE TO CLIMO WITH CHANCE POPS DURING THE
AFTERNOON AND EVENING. COULD BEGIN TO SEE A DRYING TREND BY LATE IN
THE WEEKEND INTO EARLY NEXT WEEK AS THE UPPER HIGH BUILDS
EWD...SHUNTING THE BEST MOISTURE OFFSHORE.
WITH THE LATEST MODEL RUNS PLACING THE FRONT SOUTH OF THE LOCAL
AREA...NLY FLOW AND FALLING THICKNESSES WILL LIKELY YIELD TEMPS IN
THE LOW-MID 80S. LOW-MID 80S TO CONTINUE THRU THE WEEKEND...WARMING
BACK INTO THE MID 80S BY EARLY NEXT WEEK.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
MID LVL TROF AND ASSOCIATED SFC LO PRES WILL CROSS THE REGION THIS
AFTN INTO MIDDAY TUE. EXPECT SHOWERS AND POSSIBLY A TSTM AT THE
TAF SITES INTO THIS EVENG...WITH JUST RAIN OR RAIN SHOWERS AT THE
TAF SITES FM THIS EVENG INTO MIDDAY TUE. SHOULD HAVE MAINLY VFR OR
MVFR CONDITIONS DURING THIS TIME PERIOD...BUT ISLTD IFR CONDITIONS
COULD OCCUR IN ANY HEAVIER SHOWERS OR TSTMS. MAINLY VFR CONDITIONS
EXPECTED LATE TUE THRU THU...BUT ISLTD OR SCTD PCPN (ESPLY WED AND
THU AFTN/EVENG) COULD PRODUCE LWR CIGS AND VSBYS.
&&
.MARINE...
UNSETTLED WEATHER PATTERN WILL PREVAIL OVER THE WATERS THRU THE
FORECAST PERIOD...BUT SCA CONDITIONS ARE NOT ANTICIPATED.
AREA OF LOW PRESSURE HAS LOCATED OVER WV WITH A FRONTAL BOUNDARY
EXTENDING EWD OVER SRN VA AND THE LOWER BAY. MEANWHILE...HIGH
PRESSURE BUILDS OVER THE NE STATES. THE RESULT IS GENERALLY ONSHORE
AROUND 10 KT. WAVES/SEAS AVG 1-2 FT. SFC LOW WEAKENS OVER THE CNTRL
APPALACHIANS AS AN ADDITIONAL AREA OF LOW PRESSURE DEVELOPS OVER THE
WATERS. WITH THE SFC LOW OVER THE WATERS...FLOW OVER THE COASTAL
WATERS (ON THE ERN PERIPHERY OF THE LOW) WILL BE SW OVER THE SRN
WATERS...VEERING TO E OVER THE NRN WATERS...AVG 10-15 KT. SCA
CONDITIONS ARE NOT ANTICIPATED. SEAS WILL BUILD ONLY TO 2-3 FT WITH
WAVES AVG 1-2 FT. SFC LOW SLOWLY PUSHES OFFSHORE LATE TUES-TUES
NIGHT AS HIGH PRESSURE OFF THE NE COAST RIDGES SWD OVER THE NRN
WATERS. FLOW REMAINS GENERALLY ONSHORE...AOB 15 KT. LOW PRESSURE
LINGERS OFF THE MID-ATLANTIC COAST THRU THE END OF THE WORK WEEK AND
INTO THE WEEKEND AS A FRONTAL BOUNDARY REMAINS SOUTH OF THE WATERS.
THE RESULT WILL BE ONGOING ONSHORE/NELY FLOW. GRADIENT WILL REMAIN
WEAK (AOB 15 KT)...BUT PERSISTENT NE FETCH MAY PUSH SEAS UPWARDS OF
5 FT IN THE NRN COASTAL WATERS FRIDAY NIGHT THRU THE WEEKEND.
UNDERCUT WAVEWATCH AS GFS IS NOT THE PREFERRED MEDIUM RANGE MODEL.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...ESS
NEAR TERM...ESS/JAO
SHORT TERM...ESS
LONG TERM...SAM
AVIATION...TMG
MARINE...SAM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
432 PM EDT MON AUG 18 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM EDT MON AUG 18 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A FAIRLY STRONG
SHRTWV OVER THE NRN PLAINS DRIFTING TO THE ESE INTO NW MN DOWNSTREAM
OF A RDG OVER WRN CANADA AND TOWARD A SHRTWV RDG STRETCHING FM
HUDSON BAY TOWARD THE SE GREAT LKS ON THE WRN FLANK OF A DEEP TROF
OVER THE CNDN MARITIMES. THERE IS ALSO A WEAKER SHRTWV MOVING E THRU
THE UPR LKS AHEAD OF THE MAIN DISTURBANCE APRCHG MN...AND THIS
FEATURE ALONG WITH ACCOMPANING AXIS OF GREATER H85 THETA E ADVCTN/A
FAIRLY MOIST 12Z GRB RAOB /KINX 36C AND PWAT 1.64 INCH OR ALMOST 175
PERCENT OF NORMAL/ HAS BEEN THE FOCUS FOR SOME SCT-NMRS SHOWERS
MAINLY OVER CENTRAL CWA TODAY. BUT QUITE A CONTRAST JUST TO THE E
WITH THE 12Z APX RAOB DISPLAYING A MUCH DRIER PROFILE...KINX -12C
AND PWAT 0.66 INCH OR ONLY 75 PERCENT OF NORMAL. THIS DRIER/STABLE
AIRMASS HAS SLOWED THE PROGRESS OF THE SHOWERS INTO THE AREA ARND
NEWBERRY SO FAR. THERE ARE MORE NMRS SHOWERS/A FEW TS MOVING INTO
WRN LK SUP CLOSER TO THE TRAILING SHRTWV. OTRW...QUITE A BIT OF CLD
COVER HAS LIMITED THE DIURNAL RISE OF TEMP AND DESTABILIZATION IN
THE ABSENCE OF STEEP LAPSE RATES SHOWN ON EVEN THE MOISTER 12Z GRB
RAOB...SO TS HAVE BEEN FEW AND FAR BTWN. BUT SOME HEAVY RAINS HAVE
FALLEN UNDER THE STRONGER SHOWERS WITH THE HIER PWAT/DEEPER MSTR.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS RELATED TO THE TWO
DISTURBANCES THAT ARE MOVING THRU MN/THE UPR LKS.
LATE TODAY/TNGT...AS TROF OVER QUEBEC SLOWLY EXITS TO THE E...LEAD
SHRTWV MOVING THRU THE UPR LKS/ACCOMPANYING AXIS OF H85 THETA E
ADVCTN WL DRIFT TO THE E AND BRING SOME SHOWERS TO THE FAR ERN CWA
BY 00Z. ALTHOUGH THERE MAY BE ONLY SOME ISOLD/SCT SHOWERS OVER WRN
UPR MI WITH SOME H7-5 DRYING MOST OF TODAY...MORE NMRS SHOWERS/SOME
TS ASSOCIATED WITH THE STRONGER SHRTWV MOVING INTO MN WL ARRIVE OVER
THE FAR W ARND 00Z TOWARD AREA WHERE THE 12Z NAM/REGIONAL CNDN MODEL
SHOW HIER MUCAPE UP TO ABOUT 750 J/KG NEAR IWD. BUT SINCE THE MN
SHRTWV WL BE TENDING TO DIG ESEWD THRU THE NGT...THE 12Z NAM/
REGIONAL CNDN MODEL INDICATE THE MORE NMRS SHOWERS WL IMPACT WI
CLOSER TO MORE VIGOROUS H85-7 MSTR CNVGC/HIER MUCAPE IN THE 500-
1000J/KG THAT WL BE CONFINED TO WI. SO WL MAINTAIN THE HIEST LIKELY
POPS TOWARD THE WI BORDER... ALONG WITH THE TS CHANCES PER ABSENCE
OF FCST MUCAPE AOA 200 J/KG FARTHER N. BUT DEEP LYR QVECTOR CNVGC/
DEEP SATURATION ON FCST SDNGS ON THE CYC SIDE OF SHRTWV TRACK
JUSTIFIES AT LEAST 50-60 POPS OVER THE ENTIRE CWA EVEN IF THE BETTER
FORCING/INSTABILITY HOLD TO THE SW. EXPECT LTL DIURNAL TEMP DROP
WITH LOTS OF CLDS/LINGERING HIER PWAT IN THE 1.50-1.75 RANGE. ADDED
SOME PATCHY FOG...ESPECIALLY IN AREAS OVER THE CENTRAL THAT WL
EXPERIENCE UPSLOPE SE FLOW.
TUE...EXPECT CONTINUED SCT-NMRS SHOWERS AND A FEW TS AS THE SHRTWV/
SFC LO REFLECTION SLIDE ESEWD THRU NRN WI AND MAINTAINS DEEP MSTR...
CYC FLOW AND DEEP LYR QVECTOR CNVGC OVER UPR MI. FCST WL SHOW
DIMINISHING POPS IN THE AFTN OVER THE W WITH PASSAGE OF SHRTWV TO
THE E AND ARRIVAL OF SOME DNVA/DEEP LYR QVECTOR DVGC AFT 18Z. FOG IN
THE MRNG OVER MAINLY THE CENTRAL ZNS WL DSPT SLOWLY WITH DIURNAL
HEATING LIMITED BY EXTENSIVE CLD COVER.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 431 PM EDT MON AUG 18 2014
THE 500MB LOW CENTERED OVER UPPER MI AND LAKE SUPERIOR AT 00Z
WEDNESDAY WILL SHIFT ACROSS LAKE HURON WEDNESDAY NIGHT/THURSDAY
MORNING WITH A BRIEF RIDGE BUILDING ACROSS UPPER MI THURSDAY. THE
APEX OF THE RIDGE WILL SHIFT JUST TO OUR E THURSDAY NIGHT. A SIZABLE
TROUGH SET UP FROM FROM W AND CENTRAL CANADA THROUGH THE ENTIRE W
U.S. WEDNESDAY WILL SLOWLY SHIFT THE N CENTRAL U.S. FOR THE
WEEKEND...AND UPPER GREAT LAKES SUNDAY NIGHT/MONDAY.
AS FOR THE SFC FEATURES AND WX...THE EXITING SFC LOW OVER N LAKE MI
AT 00Z WEDNESDAY WILL LINGER THROUGH THE NIGHT BEFORE SHIFTING TO
LOWER MI THROUGH THE DAY WEDNESDAY. WITH WRAP AROUND/UPSLOPE
MOISTURE ACROSS THE AREA...EXPECT LIGHT SHOWERS TO LINGER THROUGH
MID DAY AT LEAST. THE BEST CHANCE OF THUNDERSTORMS WILL SINK SE WITH
THE SFC LOW.
IT LOOKS LIKE THE ONLY PERIOD OF MAINLY DRY WEATHER WILL BE LATE
WEDNESDAY AFTERNOON THROUGH THURSDAY MORNING...DESPITE THE 500MB
RIDGE OVERHEAD THURSDAY THROUGH FRIDAY. THE LARGE HIGH PRESSURE OVER
QUEBEC...WITH A RIDGE EXTENDING OVER THE UPPER GREAT LAKES WILL EXIT
E ON FRIDAY. THERE STILL LOOKS TO BE PLENTY OF INCONSISTENCIES FOR
FRIDAY AFTERNOON ON. WILL CONTINUE TO RUN WITH A GENERAL CONSENSUS
FOR THIS PERIOD...WITH HAS AN ELONGATED SFC LOW FROM HUDSON BAY
THROUGH MN AND THE CENTRAL PLAINS AT 00Z SUNDAY. THE LOW WILL SLOWLY
SHIFT TO ONTARIO/FAR W LAKE SUPERIOR SATURDAY. THIS WOULD BRING WAA
TO THE AREA WITH HIGH TEMPS RETURNING TO NEAR NORMAL READINGS FRIDAY
AND SATURDAY. THE SFC TROUGH SHOULD BE OVER THE CWA SATURDAY
NIGHT/SUNDAY MORNING. HAVE SLOWLY DIMINISHING POPS FOR SUNDAY AND
MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 123 PM EDT MON AUG 18 2014
ALTHOUGH THE SPECIFICS ARE FAR FROM CLEAR...EXPECT IFR CONDITIONS TO
PREDOMINATE THIS FCST PERIOD WITH DEEP MSTR/SCT TO AT TIMES NMRS
SHRA OVER THE UPR LKS ASSOCIATED WITH DISTURBANCE MOVING SLOWLY
ESEWD THRU MN. BEST CHC FOR THE LOWER LIFR...AND POSSIBLY VLIFR...
CONDITIONS WL BE LATER TNGT/EARLY TUE IN THE PRESENCE OF NOCTURNAL
COOLING WHEN THE TAF SITES EXPERIENCE UPSLOPE FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 322 PM EDT MON AUG 18 2014
ADDED SOME FOG TO THE FORECAST THRU MUCH OF TUE OVER MAINLY THE
CENTRAL LAKE GIVEN ARRIVAL OF DEEPER MOISTURE AND EXPECTED AREA OF
LOWER TEMPERATURES NEAR THE LINGERING COOLEST DEEPER WATER.
OTHERWISE... EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A
RELATIVELY WEAK PRESSURE GRADIENT DOMINATES THE UPPER GREAT LAKES
ABOVE THE CHILLY WATERS OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
345 PM EDT MON AUG 18 2014
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/MARINE
.SYNOPSIS...
ISSUED AT 345 PM EDT MON AUG 18 2014
THE REGION IS HEADING INTO A WETTER PATTERN THE NEXT WEEK WITH THE
FIRST CHANCES FOR RAINFALL COMING UP TONIGHT INTO TUESDAY. ANOTHER
TIME FRAME OF PERIODS OF SHOWERS AND STORMS WILL COME FROM THURSDAY
THROUGH SUNDAY WITH A FRONTAL BOUNDARY NEAR THE AREA. SHOWERS AND
STORMS WILL BECOME MORE NUMEROUS LATE TONIGHT AND ESPECIALLY ON
TUESDAY AS AN AREA OF LOW PRESSURE MOVES INTO THE GREAT LAKES. A
GRADUAL WARMING TREND WILL BE SEEN THROUGH THE WEEK AND INTO NEXT
WEEKEND. HIGHS AROUND 80 AT THE START OF THE WEEK WILL WARM TO THE
MIDDLE 80S BY NEXT WEEKEND.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 PM EDT MON AUG 18 2014
MAIN FOCUS IN THE SHORT TERM IS ON THE CHANCES FOR SHOWERS/STORMS
TONIGHT INTO TUESDAY. PRECIPITATION WILL BE DRIVEN BY AN TROUGH
DIGGING INTO THE GREAT LAKES REGION FROM THE NORTHERN PLAINS.
MOISTURE SURGES INTO REGION THIS EVENING WITH THE HRRR TRYING TO
FLOAT CONVECTION FROM WISCONSIN OVER LAKE MICHIGAN IN THE 00Z-06Z
TIME FRAME. THINKING OUR BEST CHANCES FOR PRECIP THOUGH WILL BE
OVERNIGHT INTO TUESDAY WHEN ALL OF THE SHORT TERM MODELS FOCUS A LLJ
ON THE AREA. NOT EXPECTING SEVERE WEATHER GIVEN THE TIMING OF THE
PRECIP AND THE FACT THAT INSTABILITY WILL LIKELY BE LIMITED SOMEWHAT
BY OVERNIGHT PRECIP. 0-6KM SHEAR IS SUB 30 KNOTS BOTH TONIGHT AND
TUESDAY FOR THE MOST PART AS WELL. SOME LOCALLY HEAVY RAIN IS
POSSIBLE.
SHOWERS AND STORMS WILL BECOME MORE SCATTERED TUESDAY NIGHT THROUGH
WEDNESDAY AS THE SYSTEM FILLS OVERHEAD. PLENTY OF MOISTURE LINGERS
HOWEVER SO SCATTERED SHOWERS AND A FEW STORMS WILL REMAIN POSSIBLE
BOTH PERIODS. WEDNESDAY NIGHT KEPT THE DRY FORECAST GOING AS SURFACE
RIDGING BEGINS TO TAKE OVER AND THE UPPER LOW SLIDES SLIGHTLY OFF TO
THE EAST.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 PM EDT MON AUG 18 2014
IT LOOKS TO BE A RATHER ACTIVE EXTENDED PERIOD. THE MAIN FOCUS WILL
BE ON OPPORTUNITIES FOR SHOWERS AND STORMS THURSDAY THROUGH SUNDAY
NIGHT. BY 12Z THURSDAY...A ULJ CORE WILL BE MOVING ACROSS THE LOWER
PENINSULA AS UPPER LEVEL RIDGING BUILDINGS IN. IN CONCERT WITH THIS
WILL BE A FAIRLY STRONG H850 TEMP GRADIENT (6-8C) MOVING INTO SW
LOWER MICHIGAN AND INCREASING MID LEVEL MOISTURE. LIGHT EASTERLY
WIND CONV AT THE SFC (AS SHOWN BY THE ECMWF) MAY HELP ENHANCE
CONVECTIVE DEVELOPMENT PARTICULARLY ACROSS THE LAKESHORE REGION AND
GENERALLY ALONG AND WEST OF US 131 FOR THURSDAY EVENING INTO FRIDAY.
WHILE MODEL QPF IS NOT HIGH...INCREASING PW VALUES TO 2" OR SO ON
FRIDAY IS A CAUSE FOR CONCERN WITH ANY STORMS THAT DO DEVELOP.
LOCALLY HEAVY DOWNPOURS WOULD BE A POSSIBILITY THURSDAY NIGHT AND
FRIDAY ON THE WING OF WARM AIR ADVECTION. IF H500 HEIGHTS CONTINUE
TO BUILD STRONG ENOUGH BY SATURDAY (LIKE THE ECMWF SHOWS) THEN
PERHAPS WE WILL BE STABLE ENOUGH TO MITIGATE ANY SIGNIFICANT
CONVECTION. ON SATURDAY...GFS BUFKIT SOUNDINGS INDICATE SIGNIFICANT
SFC BASED CAPE UPWARDS OF 2000 J/KG AND LI VALUES OF -4 TO -6 BUT
WEAK SHEAR AND WEAK MID LEVEL LAPSE RATES. ECMWF WOULD SUGGEST A
LACK OF TRIGGER AND MORE STABLE CONDITIONS. OUR POP GRIDS ARE
CURRENTLY MIDDLE OF THE ROAD CHC CATEGORY FOR SATURDAY...REFLECTING
A LACK OF MODEL BULLISHNESS ON PRECIP.
UPPER LEVEL RIDGING MAY FLATTEN LATER SUNDAY AND AN ASSOCIATED
COLD FRONT COULD ARRIVE BY SUNDAY NIGHT. THE TIMING OF THIS IS
ACTUALLY AGREED UPON BY THE GFS AND ECMWF (00Z-06Z MON)...WHEREAS
THE GEM CLEARS THE FRONT 24 HOURS EARLIER. CURRENTLY AM PREFERRING A
SLOWER BREAKDOWN OF THE H500 RIDGE AND THUS A SLOWER FROPA AS SHOWN
BY THE GFS AND ECMWF. THERE WILL LIKELY BE SUFFICIENT DEEP LAYER
SHEAR BY THAT TIME TO PROVIDE A MORE CONDUCIVE ENVIRONMENT TO
STRONGER STORMS.
IN TERMS OF TEMPS AND HUMIDITY...BOTH WILL BE GOING UP BY THE
WEEKEND. DEW POINTS SHOULD CLIMB TO AROUND 70 AND HIGHS IN THE MID
80S MAY BE CONSERVATIVE FOR SATURDAY AND SUNDAY DEPENDING ON MUCH
CLOUD COVER HANGS AROUND. WOULDN`T BE SURPRISED IF HIGHS NOTCH UP
SEVERAL DEGREES WARMER WITH H850 TEMPS OF 20C KNOCKING ON THE DOOR
SATURDAY EVENING. COOLER WEATHER MOVES IN FOR EARLY NEXT WEEK BEHIND
THE FRONT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 139 PM EDT MON AUG 18 2014
THE TREND WILL BE FOR LOWERING CIGS IN THE 12Z-15Z TIME FRAME
POSSIBLY CLOSE TO IFR AS RA AND TSRA DEVELOPS AHEAD OF A FRONT IN
WISCONSIN TUESDAY. MODEL GUIDANCE IS NOT INDICATING IFR BUT
UPSTREAM OBSERVATIONS WHERE IT HAS RAINED IN WISCONSIN SUGGEST IFR
IS A DISTINCT POSSIBILITY...IN TERMS OF CIGS. HAVE THEREFORE
TRENDING CIGS TOWARD BUT NOT IN IFR FOR ALL SITES AS THE RA AND
TSRA MOVES IN DURING THE MORNING AND AFTERNOON HOURS. VISIBILITIES
SHOULD COME DOWN SOME BUT NOT IFR. CONDITIONS WILL LIKELY NOT
IMPROVE UNTIL AFTER 18Z FOR MKG AND POSSIBLY GRR AND AZO...AND A
FAIR AMOUNT LATER FOR LAN AND JXN.
&&
.MARINE...
ISSUED AT 345 PM EDT MON AUG 18 2014
MAIN IMPACT WEATHER FOR WINDS/WAVES WILL COME ON TUESDAY. SOUTH
WINDS WILL INCREASE TONIGHT INTO TUESDAY WITH WAVES BECOMING
BORDERLINE FOR BEACH HAZARDS FROM HOLLAND NORTHWARD UP THE SHORE.
EXPECTING WAVES TO PUSH INTO THE 2 TO 4 FOOT RANGE ON TUESDAY NORTH
OF HOLLAND OR SO. THE WINDS SLACKEN OFF AS WE HEAD INTO WEDNESDAY AS
THE GRADIENT BECOMES BAGGY...SO THE WAVES WILL SUBSIDE FOR MID WEEK.
&&
.HYDROLOGY...
ISSUED AT 139 PM EDT MON AUG 18 2014
RIVERS ARE RUNNING A LITTLE ABOVE NORMAL... BUT ARE STILL FAR BELOW
BANK FULL. PRECIPITATION THIS EVENING THROUGH WEDNESDAY IS EXPECTED
TO TOTAL AROUND HALF AN INCH. THIS SHOULD LEAD TO SLOW RISES ON AREA
RIVERS WITH PEAK LEVELS WELL BELOW FLOOD STAGE OCCURRING BY THE END
OF THE WEEK. LOCALLY HEAVY RAINFALL IS POSSIBLE AND COULD LEAD TO
BRIEFLY HIGHER FLOWS.
LOOKING AHEAD...IT APPEARS TO BE A RATHER ACTIVE SECOND HALF OF
AUGUST WHICH MAY HELP BRING MANY RIVERS TO ABOVE NORMAL FLOWS.
WITH AN UPPER LEVEL RIDGE DEVELOPING TO THE SOUTH OF THE GREAT
LAKES OVER THE NEXT WEEK OR SO...IT WILL PLACE MICHIGAN IN AN
ACTIVE WEATHER PATTERN WITH NUMEROUS OPPORTUNITIES FOR RAIN.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...DUKE
SHORT TERM...DUKE
LONG TERM...HOVING
AVIATION...HOVING
HYDROLOGY...63
MARINE...DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
324 PM EDT MON AUG 18 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM EDT MON AUG 18 2014
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A FAIRLY STRONG
SHRTWV OVER THE NRN PLAINS DRIFTING TO THE ESE INTO NW MN DOWNSTREAM
OF A RDG OVER WRN CANADA AND TOWARD A SHRTWV RDG STRETCHING FM
HUDSON BAY TOWARD THE SE GREAT LKS ON THE WRN FLANK OF A DEEP TROF
OVER THE CNDN MARITIMES. THERE IS ALSO A WEAKER SHRTWV MOVING E THRU
THE UPR LKS AHEAD OF THE MAIN DISTURBANCE APRCHG MN...AND THIS
FEATURE ALONG WITH ACCOMPANING AXIS OF GREATER H85 THETA E ADVCTN/A
FAIRLY MOIST 12Z GRB RAOB /KINX 36C AND PWAT 1.64 INCH OR ALMOST 175
PERCENT OF NORMAL/ HAS BEEN THE FOCUS FOR SOME SCT-NMRS SHOWERS
MAINLY OVER CENTRAL CWA TODAY. BUT QUITE A CONTRAST JUST TO THE E
WITH THE 12Z APX RAOB DISPLAYING A MUCH DRIER PROFILE...KINX -12C
AND PWAT 0.66 INCH OR ONLY 75 PERCENT OF NORMAL. THIS DRIER/STABLE
AIRMASS HAS SLOWED THE PROGRESS OF THE SHOWERS INTO THE AREA ARND
NEWBERRY SO FAR. THERE ARE MORE NMRS SHOWERS/A FEW TS MOVING INTO
WRN LK SUP CLOSER TO THE TRAILING SHRTWV. OTRW...QUITE A BIT OF CLD
COVER HAS LIMITED THE DIURNAL RISE OF TEMP AND DESTABILIZATION IN
THE ABSENCE OF STEEP LAPSE RATES SHOWN ON EVEN THE MOISTER 12Z GRB
RAOB...SO TS HAVE BEEN FEW AND FAR BTWN. BUT SOME HEAVY RAINS HAVE
FALLEN UNDER THE STRONGER SHOWERS WITH THE HIER PWAT/DEEPER MSTR.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS RELATED TO THE TWO
DISTURBANCES THAT ARE MOVING THRU MN/THE UPR LKS.
LATE TODAY/TNGT...AS TROF OVER QUEBEC SLOWLY EXITS TO THE E...LEAD
SHRTWV MOVING THRU THE UPR LKS/ACCOMPANYING AXIS OF H85 THETA E
ADVCTN WL DRIFT TO THE E AND BRING SOME SHOWERS TO THE FAR ERN CWA
BY 00Z. ALTHOUGH THERE MAY BE ONLY SOME ISOLD/SCT SHOWERS OVER WRN
UPR MI WITH SOME H7-5 DRYING MOST OF TODAY...MORE NMRS SHOWERS/SOME
TS ASSOCIATED WITH THE STRONGER SHRTWV MOVING INTO MN WL ARRIVE OVER
THE FAR W ARND 00Z TOWARD AREA WHERE THE 12Z NAM/REGIONAL CNDN MODEL
SHOW HIER MUCAPE UP TO ABOUT 750 J/KG NEAR IWD. BUT SINCE THE MN
SHRTWV WL BE TENDING TO DIG ESEWD THRU THE NGT...THE 12Z NAM/
REGIONAL CNDN MODEL INDICATE THE MORE NMRS SHOWERS WL IMPACT WI
CLOSER TO MORE VIGOROUS H85-7 MSTR CNVGC/HIER MUCAPE IN THE 500-
1000J/KG THAT WL BE CONFINED TO WI. SO WL MAINTAIN THE HIEST LIKELY
POPS TOWARD THE WI BORDER... ALONG WITH THE TS CHANCES PER ABSENCE
OF FCST MUCAPE AOA 200 J/KG FARTHER N. BUT DEEP LYR QVECTOR CNVGC/
DEEP SATURATION ON FCST SDNGS ON THE CYC SIDE OF SHRTWV TRACK
JUSTIFIES AT LEAST 50-60 POPS OVER THE ENTIRE CWA EVEN IF THE BETTER
FORCING/INSTABILITY HOLD TO THE SW. EXPECT LTL DIURNAL TEMP DROP
WITH LOTS OF CLDS/LINGERING HIER PWAT IN THE 1.50-1.75 RANGE. ADDED
SOME PATCHY FOG...ESPECIALLY IN AREAS OVER THE CENTRAL THAT WL
EXPERIENCE UPSLOPE SE FLOW.
TUE...EXPECT CONTINUED SCT-NMRS SHOWERS AND A FEW TS AS THE SHRTWV/
SFC LO REFLECTION SLIDE ESEWD THRU NRN WI AND MAINTAINS DEEP MSTR...
CYC FLOW AND DEEP LYR QVECTOR CNVGC OVER UPR MI. FCST WL SHOW
DIMINISHING POPS IN THE AFTN OVER THE W WITH PASSAGE OF SHRTWV TO
THE E AND ARRIVAL OF SOME DNVA/DEEP LYR QVECTOR DVGC AFT 18Z. FOG IN
THE MRNG OVER MAINLY THE CENTRAL ZNS WL DSPT SLOWLY WITH DIURNAL
HEATING LIMITED BY EXTENSIVE CLD COVER.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 326 AM EDT MON AUG 18 2014
THE START OF THE PERIOD WILL BE A WET ONE AS AN UPPER WAVE OVER WRN
LAKE SUPERIOR AT 12Z TUE CLOSES OFF AS IT MOVES INTO THE WRN U.P. BY
18Z TUE. THE UPPER LOW WILL THEN SLOW DOWN...FINALLY LEAVING THE
AREA LATER ON WED. THE SFC LOW WILL BE SOMEWHERE OVER NRN WI OR
ALONG THE WI/MI BORDER AT 12Z TUE AND WILL SLOWLY SHIFT E INTO TUE
NIGHT BEFORE MORE QUICKLY MOVING SE ON WED. PWATS ON TUE WILL BE
BETWEEN 1.5 AND 1.7 INCHES /NORMAL IS AROUND AN INCH/...WHICH WHEN
COMBINED WITH THE FORCING FROM THE UPPER LOW/CYCLONIC FLOW AND
UPSLOPE FLOW OFF THE GREAT LAKES IN SPOTS /ESPECIALLY OVER WRN UPPER
MI/...WILL RESULT IN DECENT PRECIPITATION PRODUCTION. THINK THAT
SOME SPOTS COULD SEE EASILY OVER AN INCH OF PRECIP ON TUE/EARLY TUE
NIGHT...DEPENDING ON SMALLER SCALE FEATURES THAT ARE NOT ENTIRELY
CLEAR AT THIS POINT. WHILE IT IS HARD TO GET TOO SPECIFIC ON
HEAVIEST PRECIP PLACEMENT/TIMING...THINK THAT MOST OF THE CWA WILL
SEE PERIODS OF RAIN TUE INTO TUE NIGHT...SO WILL INCREASE POPS TO
LIKELY IN MOST PLACES. WILL LEAVE THUNDER CHANCES TO A MINIMUM...BUT
WILL HAVE A CHANCE OF THUNDER OVER SCENTRAL AND WRN UPPER MI WHERE
CAPES WILL BE A BIT HIGHER AT AROUND 200J/KG DURING THE DAY TUE.
WITH THICK CLOUD COVER...MAX TEMPS ON TUE WILL BE IN THE MID 60S TO
LOW 70S...OR 5 TO POSSIBLY 10 DEGREES BELOW NORMAL.
WED WILL SEE DECREASING PRECIP CHANCES AS THE SYSTEM MOVES SE...BUT
DO LINGER CHANCE POPS THROUGH THE MORNING. BEHIND THE SYSTEM...AN
UPPER RIDGE DEVELOPS OVER THE REGION...WHICH WILL KEEP THINGS A BIT
DRIER THAN EARLY IN THE WEEK. MODELS DO POINT TO PRECIPITATION
OCCURRING ALONG A WARM FRONT THAT MOVES THROUGH THU INTO THU
NIGHT...BUT IT IS UNCERTAIN HOW MUCH PRECIP WILL MAKE IT INTO THE
CWA AS THE FRONT MOVES UNDER THE UPPER RIDGE AND INTO THE DRIER AIR.
WILL HAVE CHANCE POPS THU INTO THU NIGHT...AND SOME LINGERING POPS
INTO FRI.
UNCERTAINTY IS GREATER GOING INTO THE WEEKEND AS MODELS SHOW QUITE A
BIT OF VARIABILITY /RUN TO RUN AND MODEL TO MODEL/ WITH THE
STRENGTH/TRACK/TIMING OF A LOW PRESSURE SYSTEM MOVING SOMEWHERE IN
OR NEAR THE REGION. WHILE MODELS DO APPEAR TO AGREE WITH QPF ON
SAT/SAT NIGHT...THEY DO NOT AGREE ON THE REASON FOR THAT QPF...SO
CONFIDENCE IS LOWER THAN IT WOULD SEEM BY JUST LOOKING AT QPF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 123 PM EDT MON AUG 18 2014
ALTHOUGH THE SPECIFICS ARE FAR FROM CLEAR...EXPECT IFR CONDITIONS TO
PREDOMINATE THIS FCST PERIOD WITH DEEP MSTR/SCT TO AT TIMES NMRS
SHRA OVER THE UPR LKS ASSOCIATED WITH DISTURBANCE MOVING SLOWLY
ESEWD THRU MN. BEST CHC FOR THE LOWER LIFR...AND POSSIBLY VLIFR...
CONDITIONS WL BE LATER TNGT/EARLY TUE IN THE PRESENCE OF NOCTURNAL
COOLING WHEN THE TAF SITES EXPERIENCE UPSLOPE FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 322 PM EDT MON AUG 18 2014
ADDED SOME FOG TO THE FORECAST THRU MUCH OF TUE OVER MAINLY THE
CENTRAL LAKE GIVEN ARRIVAL OF DEEPER MOISTURE AND EXPECTED AREA OF
LOWER TEMPERATURES NEAR THE LINGERING COOLEST DEEPER WATER.
OTHERWISE... EXPECT WINDS UNDER 20 KTS OVER THE NEXT WEEK AS A
RELATIVELY WEAK PRESSURE GRADIENT DOMINATES THE UPPER GREAT LAKES
ABOVE THE CHILLY WATERS OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...KC
MARINE...KC
AREA FORECAST DISCUSSION
NWS JACKSON MS
330 PM CDT MON AUG 18 2014
.DISCUSSION...FORECASTING CONVECTIVE SYSTEMS CAN BE A PAIN IN THE
SUMMER...AND SUCH HAS BEEN THE CASE THIS GO ROUND. RATHER LARGE AND
MATURE THUNDERSTORM COMPLEX KNOCKING ON THE DOOR OF THE ARKLAMISS
DELTA EARLY THIS MORNING DECIDED TO DIMINISH RAPIDLY IN MAGNITUDE
AND COVERAGE AFTER SUNRISE AS IT PROGRESSED INTO THE NORTHERN
PORTIONS OF THE FORECAST AREA. ATMOSPHERIC LIFTING INHERENT WITH THE
INCOMING MID-LEVEL CONVECTIVE VORT MAX DID MANAGE TO SPARK A GOOD
DEAL OF SHOWERS AND STORMS OVER CENTRAL AND EASTERN AREAS ALTHOUGH
MUCH OF THIS ACTIVITY IS ALREADY EXITING TO THE EAST. I CAN
UNDERSTAND THE FRUSTRATION OF THOSE ANTICIPATING RAIN TODAY BUT THAT
HAVE YET TO RECEIVE ANY...BUT THE DAY IS NOT OVER YET AND THERE IS
STILL A CHANCE! GENERAL SUBSIDENCE IN THE IMMEDIATE WAKE OF THE
DEPARTING CONVECTIVE VORT WILL BE TOUGH TO OVERCOME...BUT FAR
SOUTHERN ZONES SHOULD REMAIN CLEAR OF THAT INFLUENCE INTO THE EARLY
EVENING WITH THE ENVIRONMENT IN THE WESTERN HALF OF ZONES BECOMING
GRADUALLY MORE CONDUCIVE TO THUNDERSTORM DEVELOPMENT AN HOUR OR TWO
BEFORE SUNSET. LATEST HRRR REFLECTIVITY SIMULATION DEPICTS A LOOSE
CLUSTER OF SHOWERS AND STORMS ORGANIZING NEAR I-20 OVER NORTHERN LA
IN THE NEXT FEW HOURS...AND THEN PROGRESSING TOWARD CENTRAL MS
BEFORE DIMINISHING BY MID TO LATE EVENING. THIS SOLUTION HAS SOME
MERIT...BUT IT IS MORE IMPORTANT TO NOTE THE SLIGHTLY PERTURBED
NORTHWEST FLOW SCENARIO REMAINING IN PLACE UNTIL LATE TOMORROW IS
CONDUCIVE FOR LOOSELY ORGANIZED AND SOMETIMES RANDOM CONVECTION.
AS MENTIONED...SHOWERS AND THUNDERSTORMS WILL CONTINUE TO REMAIN AT
LEAST A SLIGHT POSSIBILITY OVERNIGHT AND UNTIL LATER TUESDAY. THE
HIGHEST CHANCES WILL GENERALLY BE IN THE NORTHEAST HALF OF
ZONES...BUT EVEN THERE POPS REALLY NOT GREATER THAN 30 PERCENT. WILL
HAVE TO WATCH OUT FOR PATCHY FOG AND LOW CLOUD DEVELOPMENT BY
DAYBREAK TUESDAY...ESPECIALLY IN AREAS THAT RECEIVED DOWNPOURS
TODAY...ALTHOUGH I AM NOT ANTICIPATING A DENSE FOG ADVISORY BEING
NEEDED ANYWHERE.
FOR TOMORROW THE MAIN STORY WILL LIKELY BE MOTHER NATURE STARTING TO
TURN UP THE THERMOSTAT. OF COURSE WE WILL ALSO HAVE TO WATCH FOR A
FEW THUNDERSTORMS THROUGHOUT THE DAY...BUT CONFIDENCE IS PRETTY HIGH
ANY STORMS BY LATER ON IN THE AFTERNOON SHOULD BE CONFINED TO
SOUTHEASTERN ZONES OF MS. MAV HIGHS MAINLY IN THE 93-96 RANGE LOOK
ON TRACK WITH PEAK HEAT INDEX VALUES PEAKING NEAR OR SLIGHTLY ABOVE
THE CENTURY MARK IN A GOOD DEAL OF SPOTS.
ON WEDNESDAY THE UPPER LEVEL RIDGE WILL BUILD RIGHT ATOP THE
REGION...INCREASING HEAT AND LIMITING ANY ISOLATED AFTERNOON
THUNDERSTORMS TO SOUTH OF INTERSTATE TWENTY. TEMPERATURES WILL PEAK
IN THE MID TO UPPER 90S WITH PEAK HEAT INDEX VALUES NEAR OR SLIGHTLY
ABOVE 105 DEGREES.
AT THIS POINT THURSDAY AND FRIDAY LOOKING QUITE SIMILAR TO WEDNESDAY
IN TERMS OF HEAT AND HUMIDITY...ALTHOUGH ANY RAIN CHANCES SHOULD BE
EVEN MORE REMOTE. CONSIDERING THIS WILL LIKELY BE THE HOTTEST
STRETCH OF THE SUMMER SO FAR WE HAVE GONE AHEAD AND STARTING
MENTIONING LIMITED RISK FOR DANGEROUS HEAT IN THE HWO FOR WEDNESDAY
THROUGH FRIDAY. MODELS SUGGEST THE COMING WEEKEND MIGHT HOLD A
LITTLE MORE POTENTIAL FOR ACTUALLY REACHING FULL HEAT ADVISORY
CRITERIA...BUT THIS POTENTIAL IS STILL NOT YET HIGH ENOUGH TO BEGIN
THAT OFFICIAL ADVERTISEMENT.
MODELS TODAY CONTINUED TO PAINT THE PICTURE OF THE DOGGED RIDGE
STARTING TO BREAK DOWN EARLY NEXT WEEK...EVENTUALLY LEADING TO GOOD
RAIN CHANCES AND COOLER TEMPS BY THE MIDDLE OF NEXT WEEK. BUT THE
MIDDLE OF NEXT WEEK IS A WAYS OFF AND WE MUST BRACE FOR THE HOT
STRETCH TO COME. /BB/
&&
.AVIATION...SCATTERED SHRA/TSRA ARE MOSTLY CONFINED TO EASTERN MS
THIS AFTERNOON INTO THE EARLY EVENING AND WILL BRING A CHANCE FOR
REDUCED CIGS/VSYBS...BUT VFR CONDITIONS ARE ANTICIPATED OTHERWISE.
LATE TONIGHT INTO EARLY TUESDAY MORNING...LOW STRATUS AND FOG WITH
IFR/LIFR RESTRICTIONS WILL BE POSSIBLE AT ALL SITES. /EC/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 72 94 73 96 / 25 21 5 10
MERIDIAN 71 94 71 97 / 29 23 5 7
VICKSBURG 71 94 72 96 / 20 16 5 11
HATTIESBURG 75 95 74 96 / 15 18 8 17
NATCHEZ 74 93 73 94 / 14 15 6 17
GREENVILLE 72 96 74 97 / 23 20 5 7
GREENWOOD 71 94 73 96 / 28 24 5 7
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
BB/EC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
341 PM CDT MON AUG 18 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 341 PM CDT MON AUG 18 2014
THE MAIN FORECAST ISSUE WILL BE THE POSSIBILITY OF SOME
THUNDERSTORM ACTIVITY IN THE FAR SOUTHERN CWA OVERNIGHT.
WEST NORTHWEST FLOW ALOFT IS FAIRLY WEAK AND A NEARLY STALLED
BOUNDARY ACROSS THE CWA CONTINUES TO DRIFT SOUTH TODAY. LITTLE IF
ANY DEVELOPMENT SHOULD DEVELOP ALONG THIS BOUNDARY TODAY INTO THIS
EVENING AS A FAIRLY HEALTHY CAP KEEPS THINGS QUIET...DESPITE
MODERATE INSTABILITY IN THE 1500 TO 2000 J/KG RANGE FOR CONVECTIVE
AVAILABLE POTENTIAL ENERGY. SOME SMALL POP-UPS ARE SHOWING UP JUST
NORTH OF THE CWA...BUT THERE SHOULD BE ENOUGH OF A CAP TO TAMP
MUCH FURTHER DEVELOPMENT IN THE NORTH.
LATER ON TONIGHT...A HEALTHY 40 TO 45 KT JET WILL DEVELOP OVER
KANSAS AND WILL CURVE EAST...MOSTLY LIKELY OVER NORTH CENTRAL
KANSAS. THIS WILL SET THE STAGE FOR SOME POTENTIAL LOW-LEVEL
CONVERGENCE ACROSS OUR SOUTHERN CWA IN NORTH CENTRAL KANSAS AND
FAR SOUTHERN NEBRASKA NEAR THE AFOREMENTIONED SURFACE BOUNDARY.
THIS COULD BE JUST ENOUGH SUPPORT FOR SOME SMALL HAIL AND GUSTY
WIND IN OUR FAR SOUTH AS WELL. THE HRRR IS TRENDING STRONGER WITH
SOME DEVELOPMENT OVER THE HIGH PLAINS THIS AFTERNOON...SUPPORTED
BY ANOTHER LOW-AMPLITUDE SHORTWAVE TROUGH. THIS COULD BE ENHANCED
BY THE DEVELOPING LOW-LEVEL JET IN KANSAS AS THIS POTENTIAL
CONVECTION HEADS SOUTH. THE NAM HAS BEEN ADVERTISING SOME ACTIVITY
IN THIS VICINITY FOR THE PAST COUPLE OF DAYS. THE PRUDENT ACTION
WOULD BE TO PUT A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS BACK
INTO THE FORECAST IN OUR SOUTH. OUR CHANCES OF RAIN ARE LARGELY
DEPENDENT ON INITIAL CONVECTION IN THE HIGH PLAINS WITHIN THE
STRONGLY UNSTABLE...YET STILL CAPPED ENVIRONMENT TO THE WEST AS
THE AFOREMENTIONED TROUGH ENTERS THE CENTRAL PLAINS. THE SREF
SOLUTIONS ARE ALSO COMING IN WITH STRONGER SIGNALS TOWARD
CONVECTION IN OUR SOUTH AS WELL.
FOR TUESDAY...KEEPING IT QUIET WITH THE THINKING THAT THERE
SHOULD BE ENOUGH OF A CAP FROM PRECLUDING DEVELOPMENT UNTIL THE
EVENING HOURS. HIGH PLAINS CONVECTION COULD DEVELOP DURING THE
DAY...BUT SHOULD HOLD OFF MAKING IT HERE UNTIL EVENING...WHEN A
LOW-LEVEL JET AXIS DEVELOPS JUST TO THE WEST OF THE CWA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 PM CDT MON AUG 18 2014
GUIDANCE SUGGESTS UPPER TROPOSPHERIC RIDGING WILL EXIST OVER THE
CENTRAL CONUS TO START THE LONG TERM FORECAST PERIOD. THE RIDGE
AXIS IS EXPECTED TO SHIFT EAST SOMEWHAT BY THURSDAY OR FRIDAY
HOWEVER...ALLOWING FOR MORE OF A SOUTHWESTERLY UPPER TROPOSPHERIC
FLOW OVER OUR AREA LATE THIS WEEK INTO EARLY NEXT WEEK.
THE AXIS OF A 35-40KT LOWER TROPOSPHERIC JET STREAK...JUST ABOVE
THE BOUNDARY LAYER...IS EXPECTED DEVELOP FROM WESTERN KANSAS INTO
SOUTH CENTRAL NEBRASKA TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING.
THERMAL ADVECTION ALONG THIS AXIS APPEARS AS THOUGH IT WILL BE
SUFFICIENT FOR PRECIPITATION PRODUCTION ACROSS NORTHEASTERN
PORTIONS OF OUR CWA...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE
NAM...OPERATIONAL GFS AND EC. WENT AHEAD WITH 20-30% POPS ACROSS
OUR NORTHEAST TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING AS A
RESULT.
ON OVERALL LACK IN OMEGA SHOULD THEN PROVIDE DRY CONDITIONS TO
OUR AREA THROUGH MUCH OF THE DAY WEDNESDAY. BY LATE WEDNESDAY
AFTERNOON HOWEVER...THE NAM AND OPERATIONAL GFS BOTH SUGGEST
CONVECTION WILL INITIATE OVER THE CENTRAL HIGH PLAINS...AND THEN
MOVE EAST INTO OUR AREA WEDNESDAY EVENING AND OVERNIGHT. GIVEN
THIS...WENT AHEAD WITH 20-30% POPS ACROSS MUCH OF THE CWA
WEDNESDAY EVENING AND NIGHT.
ALTHOUGH OMEGA IS EXPECTED TO REMAIN WEAK THROUGH THE DAY
THURSDAY AS WELL...FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE
CWA...PER THE NAM AND OPERATIONAL GFS...SUGGEST A NEARLY DRY
ADIABATIC TEMPERATURE PROFILE WILL BE REALIZED FROM THE SURFACE TO
JUST ABOVE 700MB ACROSS MUCH OF THE CWA...THUS ALLOWING CONVECTIVE
TEMPERATURE READINGS TO BE REACH AND PROVIDING FOR ISOLATED
THUNDERSTORM DEVELOPMENT. THIS IS A SOLUTION ALSO SUPPORTED BY QPF
FIELDS FROM THE NAM...OPERATIONAL GFS AND EC. GIVEN ALL
THIS...WENT AHEAD WITH ~20% POPS ACROSS MUCH OF THE CWA THURSDAY
AFTERNOON AND EVENING.
HEADING INTO THURSDAY NIGHT AND BEYOND...GUIDANCE SUGGESTS
MULTIPLE UPPER TROPOSPHERIC PERTURBATIONS COULD MOVE OVER THE
CENTRAL PLAINS AS THE SOUTHWESTERLY UPPER TROPOSPHERIC FLOW
INTENSIFIES. ALLBLEND RESPONDED BY PROVIDING 20-50% POPS TO MANY
AREAS ACROSS THE CWA THURSDAY NIGHT THROUGH MONDAY...AND THESE
POPS WERE LEFT UNCHANGED FOR THE MOST PART.
FORECAST PROXIMITY SOUNDINGS FROM THE NORTHEASTERN CWA...PER THE
NAM AND OPERATIONAL GFS...SUGGEST STORM-ACCESSIBLE POTENTIAL
ENERGY WILL NOT EXCEED 200-300J/KG TUESDAY NIGHT INTO EARLY
WEDNESDAY MORNING AND THUS...WILL HOLD OFF FROM ANY MENTION OF
SEVERE WEATHER TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING.
CONVECTION ALONG THE CENTRAL HIGH PLAINS WEDNESDAY AFTERNOON AND
EVENING WILL LIKELY HAVE THE CAPABILITY TO BE STRONG...BUT THERE
IS CONSIDERABLE UNCERTAINTY AS TO HOW LONG THIS CONVECTION WILL BE
ABLE TO MAINTAIN ITS INTENSITY AS IT MOVES EAST INTO OUR AREA.
GIVEN THIS UNCERTAINTY...WILL HOLD OFF FROM ANY MENTION OF SEVERE
WEATHER ACROSS OUR AREA WEDNESDAY EVENING AND LET FUTURE SHIFTS
REEVALUATE. BEYOND WEDNESDAY EVENING...AT THIS TIME THERE ARE NO
OVERWHELMING SIGNALS OF A SIGNIFICANT SEVERE WEATHER OUTBREAK.
ALTHOUGH A FEW HIT AND MISS STRONG TO SEVERE STORMS PROBABLY
CANNOT BE RULED OUT...DUE TO THE UNCERTAINTY WILL LEAVE OUT ANY
MENTION OF SEVERE WEATHER WEDNESDAY NIGHT AND BEYOND.
LITTLE CHANGE IN THE LOWER TROPOSPHERIC AIR MASS SHOULD PROMOTE
SIMILAR TEMPERATURE READINGS FROM DAY TO DAY WEDNESDAY THROUGH
SATURDAY...WITH AFTERNOON HIGHS IN THE UPPER 80S AND 90S AND
OVERNIGHT LOWS IN THE 60S AND LOWER 70S EXPECTED FOR THE MOST
PART. BEYOND SATURDAY...GUIDANCE DOES SUGGEST A LOWER TROPOSPHERIC
BAROCLINIC ZONE WILL MOVE ACROSS THE AREA...THUS ALLOWING A COOLER
LOWER TROPOSPHERIC AIR MASS INTO THE REGION. AFTERNOON HIGHS IN
THE UPPER 70S TO MID 80S AND LOWS GENERALLY IN THE 60S ARE
CURRENTLY EXPECTED TO FINISH THE LONG TERM FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1243 PM CDT MON AUG 18 2014
WITH WEAK WEATHER FEATURES AT THE SURFACE AND LIGHT FLOW
ALOFT...WEATHER WILL BE RATHER BENIGN FOR THIS FORECAST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...HEINLEIN
LONG TERM...BRYANT
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
228 PM EDT MON AUG 18 2014
.SYNOPSIS...
HIGH PRESSURE WILL KEEP OUR WEATHER QUIET THROUGH EARLY TUESDAY.
AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS CAN THEN BE
EXPECTED LATE TUESDAY INTO ESPECIALLY WEDNESDAY AND THURSDAY...AS
A LOW PRESSURE SYSTEM MOVES THROUGH THE GREAT LAKES REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
1045 AM UPDATE... BASED ON LATEST
VISIBLE SATELLITE LOOP SHOWING AN EXTENSIVE AREA OF STRATOCU
FORMING OVER A LARGE SECTION OF OUR AREA, I INCREASED SKY COVER
THROUGH 18Z. AFTER THAT TIME RUC SOUNDINGS SHOW RAPID INCREASING
AMOUNTS OF DRY AIR UNDERNEATH THE SUBSIDENCE INVERSION. WITH THAT
IN MIND WE SHOULD SEE A SUBSTANTIAL INCREASE IN SUNSHINE THIS
AFTERNOON, WITH A MOSTLY SUNNY SKY BY 21Z. WE CAN SEE THIS
HAPPENING ALREADY OVER NORTHERN NY. ASIDE FROM THE SKY CHANGE, OUR
TEMPS ARE ON TRACK.
645 AM UPDATE... BROAD SURFACE HIGH PRESSURE WILL SHIFT
FROM CENTRAL ONTARIO INTO WESTERN QUEBEC-NORTHERN NEW YORK TODAY
THROUGH TONIGHT. INTERESTINGLY ENOUGH...UNDER THE CENTER OF THE
HIGH...TIMMINS ONTARIO WAS DOWN TO 37 DEGREES AS OF 6 AM...AND
ROUYN-NORANDA IN EXTREME WESTERN QUEBEC WAS DOWN TO 34 DEGREES.
WHILE THE CENTER OF THE HIGH WILL PASS TO OUR NORTH...IT WILL
STILL DOMINATE THE WEATHER IN CENTRAL NEW YORK TO NORTHEAST
PENNSYLVANIA...KEEPING THINGS PRETTY QUIET IN THE NEAR TERM. AND
AS HINTED AT ABOVE...A CHILLY NIGHT TONIGHT ESPECIALLY MOHAWK
VALLEY-WESTERN CATSKILLS.
A VERY WEAK WAVE DROPPED THROUGH THE STILL BRISK NORTHWEST FLOW
ALOFT OVERNIGHT...ALLOWING SOME CLOUDS AND EVEN A COUPLE SPRINKLES
TO SETTLE ACROSS CENTRAL NEW YORK DURING THE PREDAWN HOURS.
HOWEVER...THE CLOUDS HAVE TENDED TO SCATTER OUT WHILE EDGING SOUTHWARD
ACROSS THE TWIN TIERS. THUS...PATCHY DENSE FOG AND/OR LOW STRATUS
HAS FORMED ESPECIALLY IN THE VALLEYS OF THE TWIN TIERS AS WELL AS
NORWICH AND SIDNEY. ALSO SOME LOW STRATUS HANGING OVER ITHACA. THOSE
CLOUDS FOR SOME AND VALLEY FOG FOR OTHERS WILL DISSIPATE THE NEXT
FEW HOURS...LEADING TO A MOSTLY SUNNY AND PLEASANT DAY WITH
TEMPERATURES A SHADE BELOW CLIMATOLOGICAL AVERAGES.
FOR TONIGHT...A WEAK SYSTEM BOUND FOR THE MIDATLANTIC COAST WILL
BE WELL SOUTH OF US...YET CLOSE ENOUGH FOR SOME INCREASE IN CLOUDS
TOWARDS DAWN FROM CENTRAL TWIN TIERS TO NEPA. HOWEVER...NY THRUWAY
CORRIDOR TO WESTERN CATSKILLS SHOULD REMAIN CLEAR ALL NIGHT. WHILE
NOT AS COLD AS THAT READING MENTIONED ABOVE IN EXTREME WESTERN
QUEBEC...STRONG RADIATIONAL COOLING WILL MANAGE TO SEND TEMPERATURES
INTO THE LOW TO MID 40S IN THE TYPICALLY COLDER SPOTS OF UPPER
SUSQUEHANNA-MOHAWK VALLEY-WESTERN CATSKILL VALLEYS FOR LOWS.
QUITE CHILLY FOR MID AUGUST. FARTHER SOUTH AND WEST...WHERE CLOUDS
WILL INCREASE LATE...LOWS WILL STILL BE ON THE COOL SIDE IN THE
UPPER 40S TO LOW 50S...EXCEPT FOR MID 50S TOWARDS WYOMING VALLEY
OF PA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
345 AM UPDATE...
A TROUGH WILL DIG INTO THE UPPER MIDWEST AND CUT OFF AN UPPER LOW
ON TUESDAY...WITH A WEAK SURFACE LOW FORMING OVER EAST-CENTRAL
WISCONSIN AS A RESULT. WELL AHEAD OF THE LOW...WARM AIR ADVECTION
IN OUR REGION WILL ALLOW TEMPERATURES AND DEWPOINTS TO CREEP UP
ENOUGH FOR SOME MARGINAL INSTABILITY TUESDAY AFTERNOON...THOUGH
BETTER IN WESTERN PORTIONS OF NY-PA. I HAVE INCLUDED SLIGHT TO LOW
CHANCE OF SHOWERS AND THUNDERSTORMS /NOT STRONG/...FOCUSED MAINLY
WEST OF A TOWANDA-ITHACA-AUBURN LINE. MOST OF OUR AREA WILL BE DRY
TUESDAY...WITH NEAR NORMAL TEMPERATURES...AND EVEN A DECENT AMOUNT
OF SUNSHINE AT LEAST IN CENTRAL NY.
SOUTHWEST FLOW ALOFT TUESDAY NIGHT...AHEAD OF APPROACHING UPPER
LOW...WILL BRING MORE MOISTURE INTO THE COLUMN. EMBEDDED WEAK
WAVES WITHIN THE FLOW MAY REALIZE SOME SHOWERS...THOUGH WITH NO
DIURNAL HEATING...THEY SHOULD BE LIMITED IN COVERAGE. CLOUDS
THOUGH WILL DEFINITELY BE INCREASING.
WEDNESDAY-WEDNESDAY NIGHT...AREAWIDE CHANCES FOR SHOWERS WILL GO
UP MARKEDLY. BOTH UPPER LOW AND SURFACE LOW /AND ITS OCCLUDING
FRONT/ WILL ADVANCE ACROSS CENTRAL GREAT LAKES WEDNESDAY...THEN
ENTERING OUR REGION WEDNESDAY NIGHT. HOWEVER...SURFACE HIGH
PRESSURE RIDGE WILL BE HOLDING STRONG ACROSS NEW ENGLAND...AND
SOUTHEAST-TO-SOUTH LOW LEVEL FLOW FROM IT MAY HAVE STABILIZING
INFLUENCE ON AT LEAST OUR EASTERN ZONES. SO WHILE SHOWERS ARE A
GOOD BET...THUNDER CHANCES MAY BE A BIT MUTED EAST OF HIGHWAY 81.
FARTHER WEST...MARGINAL INSTABILITY WILL HAVE A LITTLE BETTER
CHANCE OF BEING REALIZED AS EMBEDDED THUNDER WITHIN THE SHOWERS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
230 PM UPDATE...
MEDIUM RANGE MODELS CONTINUE TO SUGGEST A RATHER BLOCKY PATTERN
ACROSS THE NORTHERN HEMISPHERE WHICH WILL MAKE THIS FORECAST NOT
THAT CLEAR CUT. THE INDIVIDUAL MODEL SOLUTIONS ARE NOT TOO FAR OFF
IN THE DETAILS...RIGHT NOW...BUT GIVEN THE NATURE OF ATMOSPHERIC
BLOCKS THEY COULD EASILY WAVER BACK AND FORTH DURING THE WEEK. AS
IT STANDS NOW...A CLOSED LOW OFF THE EASTERN SEABOARD WILL STILL
HAVE ENOUGH OF AN INFLUENCE TO KEEP A SOLID CHANCE FOR SHOWERS IN
THE REGION ON THURSDAY NIGHT. THEN...GFS AND ECMWF INDICATE
CNY/NEPA WILL COME UNDER THE INFLUENCE OF A COL AREA OF WEAK
RIDGING BETWEEN TWO CUTOFF LOWS WITH SFC HIGH PRESSURE NOSING
SOUTH FROM NEW ENGLAND. THIS WILL LIKELY LEAD TO A MAINLY DRY
FORECAST THROUGH THE WEEKEND...UNTIL A MORE PROGRESSIVE NORTHERN
STREAM TROF AND COLD FRONT APPROACHES FOR MONDAY. TEMPERATURES
THROUGH THE PERIOD LOOK TO BE NEAR NORMAL WITH HIGHS IN THE UPPER
70S AND LOWS IN THE UPPER 50S.
OVERALL CONFIDENCE IN THIS FORECAST IS LOW TO MEDIUM IN THIS PATTERN.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
1:45 PM UPDATE...
THE PRIMARY FOCUS IS THE FOG FORMATION IN ELM LATER TONIGHT INTO
THE EARLY MORNING. AS OVERNIGHT LOWS DROP BELOW THE AFTERNOON
CROSSOVER TEMP, IFR VSBYS MAY BE POSSIBLE BETWEEN 04Z AND 07Z. AS
FOG INCREASES ELM WILL PROGRESS INTO THE LIFR TERRITORY BY 08Z.
EXPECT LIFR CONDITIONS AT LEAST ON A TEMPO BASIS AT ELM THROUGH
ABOUT 0800-1200Z. BASED ON CLIMO WE SHOULD SEE A RETURN TO VFR
HERE BY 14Z.
ELSEWHERE VFR IS EXPECTED THROUGH THE END OF THE TAF PERIOD, WITH
A GRADUAL INCREASE IN MID CLOUDS AROUND 4KFT TOMORROW ESPECIALLY
SOUTHERN TERMINALS.
WINDS WILL BE LIGHT AND VARIABLE FOR ALL STATIONS IN THE REGION
THROUGH TOMORROW AFTERNOON.
OUTLOOK...
TUE-WED MORN...VFR.
WED AFTN-SAT...MVFR RESTRICTIONS POSSIBLE IN SHRA/TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...HEDEN/MDP
SHORT TERM...MDP
LONG TERM...JAB
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
201 PM EDT MON AUG 18 2014
.SYNOPSIS...
HIGH PRESSURE WILL KEEP OUR WEATHER QUIET THROUGH EARLY TUESDAY.
AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS CAN THEN BE
EXPECTED LATE TUESDAY INTO ESPECIALLY WEDNESDAY AND THURSDAY...AS
A LOW PRESSURE SYSTEM MOVES THROUGH THE GREAT LAKES REGION.
&&
.NEAR TERM /THROUGH TONIGHT/...
1045 AM UPDATE... BASED ON LATEST
VISIBLE SATELLITE LOOP SHOWING AN EXTENSIVE AREA OF STRATOCU
FORMING OVER A LARGE SECTION OF OUR AREA, I INCREASED SKY COVER
THROUGH 18Z. AFTER THAT TIME RUC SOUNDINGS SHOW RAPID INCREASING
AMOUNTS OF DRY AIR UNDERNEATH THE SUBSIDENCE INVERSION. WITH THAT
IN MIND WE SHOULD SEE A SUBSTANTIAL INCREASE IN SUNSHINE THIS
AFTERNOON, WITH A MOSTLY SUNNY SKY BY 21Z. WE CAN SEE THIS
HAPPENING ALREADY OVER NORTHERN NY. ASIDE FROM THE SKY CHANGE, OUR
TEMPS ARE ON TRACK.
645 AM UPDATE... BROAD SURFACE HIGH PRESSURE WILL SHIFT
FROM CENTRAL ONTARIO INTO WESTERN QUEBEC-NORTHERN NEW YORK TODAY
THROUGH TONIGHT. INTERESTINGLY ENOUGH...UNDER THE CENTER OF THE
HIGH...TIMMINS ONTARIO WAS DOWN TO 37 DEGREES AS OF 6 AM...AND
ROUYN-NORANDA IN EXTREME WESTERN QUEBEC WAS DOWN TO 34 DEGREES.
WHILE THE CENTER OF THE HIGH WILL PASS TO OUR NORTH...IT WILL
STILL DOMINATE THE WEATHER IN CENTRAL NEW YORK TO NORTHEAST
PENNSYLVANIA...KEEPING THINGS PRETTY QUIET IN THE NEAR TERM. AND
AS HINTED AT ABOVE...A CHILLY NIGHT TONIGHT ESPECIALLY MOHAWK
VALLEY-WESTERN CATSKILLS.
A VERY WEAK WAVE DROPPED THROUGH THE STILL BRISK NORTHWEST FLOW
ALOFT OVERNIGHT...ALLOWING SOME CLOUDS AND EVEN A COUPLE SPRINKLES
TO SETTLE ACROSS CENTRAL NEW YORK DURING THE PREDAWN HOURS.
HOWEVER...THE CLOUDS HAVE TENDED TO SCATTER OUT WHILE EDGING SOUTHWARD
ACROSS THE TWIN TIERS. THUS...PATCHY DENSE FOG AND/OR LOW STRATUS
HAS FORMED ESPECIALLY IN THE VALLEYS OF THE TWIN TIERS AS WELL AS
NORWICH AND SIDNEY. ALSO SOME LOW STRATUS HANGING OVER ITHACA. THOSE
CLOUDS FOR SOME AND VALLEY FOG FOR OTHERS WILL DISSIPATE THE NEXT
FEW HOURS...LEADING TO A MOSTLY SUNNY AND PLEASANT DAY WITH
TEMPERATURES A SHADE BELOW CLIMATOLOGICAL AVERAGES.
FOR TONIGHT...A WEAK SYSTEM BOUND FOR THE MIDATLANTIC COAST WILL
BE WELL SOUTH OF US...YET CLOSE ENOUGH FOR SOME INCREASE IN CLOUDS
TOWARDS DAWN FROM CENTRAL TWIN TIERS TO NEPA. HOWEVER...NY THRUWAY
CORRIDOR TO WESTERN CATSKILLS SHOULD REMAIN CLEAR ALL NIGHT. WHILE
NOT AS COLD AS THAT READING MENTIONED ABOVE IN EXTREME WESTERN
QUEBEC...STRONG RADIATIONAL COOLING WILL MANAGE TO SEND TEMPERATURES
INTO THE LOW TO MID 40S IN THE TYPICALLY COLDER SPOTS OF UPPER
SUSQUEHANNA-MOHAWK VALLEY-WESTERN CATSKILL VALLEYS FOR LOWS.
QUITE CHILLY FOR MID AUGUST. FARTHER SOUTH AND WEST...WHERE CLOUDS
WILL INCREASE LATE...LOWS WILL STILL BE ON THE COOL SIDE IN THE
UPPER 40S TO LOW 50S...EXCEPT FOR MID 50S TOWARDS WYOMING VALLEY
OF PA.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
345 AM UPDATE...
A TROUGH WILL DIG INTO THE UPPER MIDWEST AND CUT OFF AN UPPER LOW
ON TUESDAY...WITH A WEAK SURFACE LOW FORMING OVER EAST-CENTRAL
WISCONSIN AS A RESULT. WELL AHEAD OF THE LOW...WARM AIR ADVECTION
IN OUR REGION WILL ALLOW TEMPERATURES AND DEWPOINTS TO CREEP UP
ENOUGH FOR SOME MARGINAL INSTABILITY TUESDAY AFTERNOON...THOUGH
BETTER IN WESTERN PORTIONS OF NY-PA. I HAVE INCLUDED SLIGHT TO LOW
CHANCE OF SHOWERS AND THUNDERSTORMS /NOT STRONG/...FOCUSED MAINLY
WEST OF A TOWANDA-ITHACA-AUBURN LINE. MOST OF OUR AREA WILL BE DRY
TUESDAY...WITH NEAR NORMAL TEMPERATURES...AND EVEN A DECENT AMOUNT
OF SUNSHINE AT LEAST IN CENTRAL NY.
SOUTHWEST FLOW ALOFT TUESDAY NIGHT...AHEAD OF APPROACHING UPPER
LOW...WILL BRING MORE MOISTURE INTO THE COLUMN. EMBEDDED WEAK
WAVES WITHIN THE FLOW MAY REALIZE SOME SHOWERS...THOUGH WITH NO
DIURNAL HEATING...THEY SHOULD BE LIMITED IN COVERAGE. CLOUDS
THOUGH WILL DEFINITELY BE INCREASING.
WEDNESDAY-WEDNESDAY NIGHT...AREAWIDE CHANCES FOR SHOWERS WILL GO
UP MARKEDLY. BOTH UPPER LOW AND SURFACE LOW /AND ITS OCCLUDING
FRONT/ WILL ADVANCE ACROSS CENTRAL GREAT LAKES WEDNESDAY...THEN
ENTERING OUR REGION WEDNESDAY NIGHT. HOWEVER...SURFACE HIGH
PRESSURE RIDGE WILL BE HOLDING STRONG ACROSS NEW ENGLAND...AND
SOUTHEAST-TO-SOUTH LOW LEVEL FLOW FROM IT MAY HAVE STABILIZING
INFLUENCE ON AT LEAST OUR EASTERN ZONES. SO WHILE SHOWERS ARE A
GOOD BET...THUNDER CHANCES MAY BE A BIT MUTED EAST OF HIGHWAY 81.
FARTHER WEST...MARGINAL INSTABILITY WILL HAVE A LITTLE BETTER
CHANCE OF BEING REALIZED AS EMBEDDED THUNDER WITHIN THE SHOWERS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
305 AM UPDATE...
DIFFUSE LONG WAVE TROF WILL REMAIN FIXED OVER EASTERN CANADA THIS
PERIOD, EXTENDING SOUTHWESTWARD THROUGH NY AND PA. THIS WILL KEEP
OUR WEATHER UNSETTLED THROUGH THE WORK WEEK, WITH A CHANCE FOR A
SHOWER OR THUNDERSTORM EACH DAY.
THE HIGHEST POTENTIAL DAY FOR CONVECTION APPEARS TO BE THURSDAY,
WHEN A WEAK SURFACE WAVE RIDES OUT OF THE OHIO VALLEY. MID LEVEL
LAPSE RATES WILL INCREASE TO 6 TO 6.5 PER THE LATEST ECMWF
PROG...LOW END MARGINAL FOR DECENT CONVECTION BUT UNSTABLE ENOUGH
TO SUGGEST AN INCREASED THREAT FOR PRECIPITATION.
PREV DISCUSSION...
TROFFINESS CONTS AT THE BEGINNING OF THE LONG TERM. 12Z GFS IS
TRYING TO DVLP A REX BLOCK OVR THE NORTHEAST BY MID- WEEK. HV
UNDERCUT WPC GUIDANCE SLIGHTLY WITH HICHC POPS EXPECTED ON WED
NGT. PATTERN STILL LOOKS TO BE UP IN THE AIR AND NOT CONFIDENT
ENUF TO GO LKLY THIS FAR OUT.
CHC POPS CONTINUE EACH PD WITH UPR LOW SPINNING IN THE GULF OF MAINE
THRU THE END OF THE LONG TERM WITH 590 RIDGE BUILDING INTO THE
MIDWEST LVG CWA IN NW FLOW PATTERN. THIS PATTERN WL LKLY THROW
SUBTLE S/WVS AT RANDOM INTO THE NE U.S. IN CONTRAST, 12Z CMC KEEPS
AREA IN ZONAL FLOW DUE TO H5 RIDGE AXIS BEING SUPPRESSED DOWN ALONG
THE GULF COAST.
SFC HIPRES BUILDS IN FM CANADIAN MARITIMES AND SHUNTS CHC POPS TO
THE EAST BUT NOT COMPLETELY OUT OF THE AREA ON SATURDAY. SFC RIDGE
AXIS BUILDS EVEN FURTHER TO THE WEST SAT NGT ACCOMPANIED BY BUILDING
H5 RIDGE WHICH MAY LEAD TO A DRY PD DRG THE LATTER HALF OF THE
WEEKEND.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
1:45 PM UPDATE...
THE PRIMARY FOCUS IS THE FOG FORMATION IN ELM LATER TONIGHT INTO
THE EARLY MORNING. AS OVERNIGHT LOWS DROP BELOW THE AFTERNOON
CROSSOVER TEMP, IFR VSBYS MAY BE POSSIBLE BETWEEN 04Z AND 07Z. AS
FOG INCREASES ELM WILL PROGRESS INTO THE LIFR TERRITORY BY 08Z.
EXPECT LIFR CONDITIONS AT LEAST ON A TEMPO BASIS AT ELM THROUGH
ABOUT 0800-1200Z. BASED ON CLIMO WE SHOULD SEE A RETURN TO VFR
HERE BY 14Z.
ELSEWHERE VFR IS EXPECTED THROUGH THE END OF THE TAF PERIOD, WITH
A GRADUAL INCREASE IN MID CLOUDS AROUND 4KFT TOMORROW ESPECIALLY
SOUTHERN TERMINALS.
WINDS WILL BE LIGHT AND VARIABLE FOR ALL STATIONS IN THE REGION
THROUGH TOMORROW AFTERNOON.
OUTLOOK...
TUE-WED MORN...VFR.
WED AFTN-SAT...MVFR RESTRICTIONS POSSIBLE IN SHRA/TSRA.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...HEDEN/MDP
SHORT TERM...MDP
LONG TERM...DJP/PVN
AVIATION...HEDEN/JSY
AREA FORECAST DISCUSSION
NWS BISMARCK ND
318 PM CDT MON AUG 18 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 318 PM CDT MON AUG 18 2014
DIURNAL CONVECTION THROUGH SUNSET THIS EVENING AND FOG TONIGHT
HIGHLIGHT THE SHORT TERM.
DIURNAL SCATTERED CONVECTION IS EXPECTED TO REMAIN FOCUSED ACROSS
THE SOUTH CENTRAL AND JAMES RIVER VALLEY GIVEN RADAR AND SATELLITE
TRENDS THROUGH 1930 UTC...AND THE 16-17 UTC HRRR ITERATIONS.
MODEST INSTABILITY AND WEAK SHEAR ARE EXPECTED TO KEEP STORMS
BELOW SEVERE LIMITS. HOWEVER...THE NON SUPERCELL TORNADO OR
LANDSPOUT PARAMETER HAS A LOCAL MAXIMA ACROSS THE JAMES RIVER
VALLEY INTO THE SOUTHERN RED RIVER VALLEY WITH STEEP LOW LEVEL
LAPSE RATES AND ENVIRONMENTAL VORTICITY. THUS...WOULD NOT BE
SURPRISED BY A FUNNEL CLOUD REPORT.
FOR TONIGHT...WITH WEAK SURFACE HIGH PRESSURE IN PLACE...CLEAR
SKIES...LIGHT WINDS AND PLENTIFUL MOISTURE FROM WEEKEND RAINS...AREAS
OF FOG ARE POSSIBLE ACROSS MUCH OF THE AREA TONIGHT.
TUESDAY WILL BE THE ONLY DRY DAY IN THE FORECAST UNDER SHORTWAVE
RIDGING BEFORE A RETURN TO AN ACTIVE WEATHER PATTERN THROUGH THE
EXTENDED.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 318 PM CDT MON AUG 18 2014
A SLOW MOVING TROUGH EXTENDING FROM THE NORTHWEST TERRITORIES WILL
PRODUCE CHANCES FOR WIDESPREAD SHOWERS/THUNDERSTORMS FROM WEDNESDAY
INTO THE WEEKEND. CHANCES FOR PRECIPITATION WILL CONTINUE THROUGH
THE EXTENDED...AS UNSETTLED SOUTHWESTERLY FLOW REMAINS OVER THE
AREA.
HEAVY RAINFALL IS EXPECTED OVER WESTERN AND CENTRAL PORTIONS OF THE
STATE WEDNESDAY INTO THURSDAY...WITH ADDITIONAL RAINFALL THROUGH THE
WEEKEND. WESTERN AND CENTRAL AREAS HAVE ALREADY BEEN SATURATED WITH
ABUNDANT RAINFALL...FLOODING ISSUES REMAIN A CONCERN.
TEMPERATURES WILL NEAR AVERAGE FOR WEDNESDAY AND THURSDAY. A
COOLER AIRMASS BEGINS MOVING INTO THE AREA BY FRIDAY MORNING...HIGHS
WILL RANGE BETWEEN 10 AND 15 DEGREES BELOW AVERAGE THROUGH THE REST
OF THE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 318 PM CDT MON AUG 18 2014
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS MAY IMPACT KJMS
AND KBIS THROUGH SUNSET. THEREAFTER...AREAS OF FOG ARE POSSIBLE
TONIGHT WITH SURFACE HIGH PRESSURE IN PLACE. HOWEVER...IMPACTS TO
ANY ONE TERMINAL ARE UNCERTAIN.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...AYD
LONG TERM...AC
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
148 PM CDT MON AUG 18 2014
.UPDATE...
POOL OF DEEP MOISTURE/SHORTWAVE MOVING ACROSS WEAK LOW-LEVEL
BOUNDARY HELPING TO DEVELOP NUMEROUS SHWRS/STRMS ACROSS THE
SOUTH/SCATTERED NORTH. EXPECT THIS TREND TO CONTINUE INTO THE
EARLY EVE. WILL RAISE POPS SLIGHTLY FOR THE AFTERNOON EXCEPT
EXTREME NORTH. NO CHANGES OTHERWISE.
&&
AVIATION...18Z TAF DISCUSSION.
LOW-LEVEL MOISTURE WILL REMAIN HIGH INTO TUESDAY MORNING.
OUTSIDE OF DEVELOPING CONVECTION...EXPECT VFR CONDITIONS
INTO THE EVENING BUT MVFR/IFR LEVEL CIGS/VSBYS ARE AGAIN
EXPECTED TO DEVELOP OVERNIGHT...HANGING AROUND UNTIL 14-15Z
TUES. BNA/CSV MOST LIKELY TO SEE CONVECTION THRU 03Z TUES.
&&
.PREV DISCUSSION... /ISSUED 637 AM CDT MON AUG 18 2014/
UPDATE...
12Z TAF DISCUSSION.
AVIATION...
SCT -SHRA CONTINUE TO DEVELOP ACROSS THE MID STATE ALTHOUGH MAINLY
SOUTH OF AREA AIRPORTS...SO WILL MENTION VCSH AT BNA/CSV THROUGH
18Z IN LINE WITH LATEST HRRR MODEL. VFR CIGS EXPECTED AT BNA/CSV
TODAY...WHILE CURRENT IFR CIGS/VIS AT CKV WILL IMPROVE TO VFR BY
LATE MORNING. LIGHT SOUTHWEST TO WEST WINDS ARE ANTICIPATED
THROUGH THE TAF PERIOD.
SHAMBURGER
PREV DISCUSSION... /ISSUED 456 AM CDT MON AUG 18 2014/
DISCUSSION...
SHOWERS AND THUNDERSTORMS DEVELOPING OVER THE LAST COUPLE OF HOURS
SOUTH OF I-40. SOUTHERN MAURY AND MARSHALL COUNTIES APPEAR TO BE
EXPERIENCING THE HEAVIEST RAINFALL THIS MORNING...WITH RADAR
ESTIMATING AROUND 1 TO 2 INCHES AND MORE RAIN ON THE WAY. SHOWERS
APPEAR TO BE BACK BUILDING AND TRAINING OVER THE SAME
AREAS...FURTHER INCREASING THE THREAT FOR FLASH FLOODING FOR
SOUTHERN MIDDLE TENNESSEE. PWATS REMAIN AROUND 2 INCHES WITH
UNIDIRECTIONAL FLOW THROUGHOUT THE MORNING. THE BULK OF THIS
ACTIVITY WILL PUSH EAST THROUGHOUT THE MORNING...BUT MORE SHOWERS
WITH HEAVY DOWNPOURS WILL BE POSSIBLE THROUGHOUT THE DAY.
TUESDAY`S THUNDERSTORM ACTIVITY LOOKS TO BE MORE WIDELY
SCATTERED...WITH THE BEST CHANCE OVER THE CUMBERLAND PLATEAU
DURING THE EVENING HOURS. WEDNESDAY AND THURSDAY CONDITIONS BEGIN
TO DRY OUT AS HIGH PRESSURE BUILDS OVER THE LOWER MS VALLEY. WILL
STILL CARRY A SLIGHT CHANCE OF SHOWERS AND STORMS OVER THE PLATEAU
THROUGH THE END OF THE FORECAST PERIOD AS EAST TENNESSEE REMAINS
UNDER NORTHWEST FLOW AND IS INFLUENCED BY AN AREA OF LOW PRESSURE
MOVING ACROSS THE NORTHEAST U.S.
THE MAIN STORY AFTER TODAY WILL BE OUR WARMING TREND WITH THE HIGH
PRESSURE BUILDING JUST TO OUR SOUTHWEST...TEMPERATURES ARE
EXPECTED TO SOAR INTO THE MID TO UPPER 90S AFTER TUESDAY.
APPARENT TEMPS COULD BE AROUND 100 DEGREES FOR THE LATTER HALF OF
THE WORK WEEK. WARM TEMPS AND DRY WEATHER WILL CONTINUE INTO NEXT
WEEKEND.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
350 PM CDT MON AUG 18 2014
.SHORT TERM...
(Tonight and Tuesday)
Low confidence forecast across West Central Texas for the next 24
hours. Remnant Mesoscale Convective Vortex (MCV) continues to
remain nearly stationary across Sterling County early this
afternoon, and buried within a larger scale mid level shear axis
stretching across much of the area. Much like we saw on Sunday, as
the main morning area of showers and storms slowly winds down from
Abilene to Brownwood, more scattered convection is developing
along the periphery of the MCV where better heating is taking
place.
Biggest question in the forecast concerns tonight and Tuesday
rain chances. As the low level jet intensifies towards midnight,
expect to see another round of showers and storms form near the
center of the MCV and along its eastern flank. MCV is definitely
weaker today than it was yesterday, and should continue to slowly
wind down. How strong it remains tonight, where it ends up, and
what kind of storm coverage it can actually generate is highly
uncertain though. Models not a lot of help, with even the TTU WRF
and the HRRR models struggling in this highly mesoscale situation.
At this point, will bump pops to chance for most of the area,
knowing that some areas may miss out and others may see some
decent rainfall. Some of this area has seen rainfall totals in the
1 to 3 inch range, so if the rain can train over these areas, than
a flood threat becomes more pronounced. This will need to be
monitored through tonight.
07
.LONG TERM...
(Tuesday night through next Monday)
A mainly dry forecast expected for the extended period.
By Tuesday evening...the 500mb ridge that is currently centered
near Florida will expand farther west into Texas, pushing the
shear axis over the top of our CWA farther west as well. In
addition, by Tuesday night, 250mph ridging will move in over the
top of the region out of the southwest. These two factors point to
decreasing chances of precipitation overall for the area by
Tuesday night. However, we have left an area of slight chance PoPs
in for Tuesday evening. The combination of the previously
mentioned upper level shear axis and MCV is expected to result in
additional thunderstorm activity tomorrow afternoon. And although
these features are expected to be drifting to the west, there
could still be lingering activity for areas mainly south and west
of a Sterling City to San Angelo to Sonora line.
By Wednesday, upper level ridging will be in place across our
forecast area, effectively ending rain chances through the end of
the forecast period, and allowing temperatures to remain warm in
the mid to upper 90s for highs, and generally lower to mid 70s for
lows.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 72 94 71 97 74 / 30 30 5 5 5
San Angelo 71 93 72 95 74 / 30 30 10 5 5
Junction 73 92 73 93 73 / 30 30 10 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1257 PM CDT MON AUG 18 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 324 AM CDT MON AUG 18 2014
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED TROUGHING FROM LAKE WINNIPEG INTO THE DAKOTAS AND RIDGING
OVER MICHIGAN. BETWEEN THESE TWO FEATURES...THERE WERE SHORTWAVES
NEAR LA CROSSE AND IN SOUTHEAST SOUTH DAKOTA. DPVA FROM THE FORMER
SHORTWAVE...COMBINED WITH A ZONE OF 850MB MOISTURE TRANSPORT WHICH
EXTENDED FROM NORTH CENTRAL IA INTO NORTH CENTRAL WI...HAS RESULTED
IN SCATTERED TO NUMEROUS CONVECTION OVER THE NORTHWEST HALF OF THE
FORECAST AREA. PRECIPITABLE WATER VALUES FROM THE RAP SHOW VALUES OF
1.5-1.8 INCHES IN GENERAL...HIGHEST WITHIN THE CONVECTION. THESE
HIGH VALUES HAS ALLOWED CONVECTION TO HAVE HEAVY RAINFALL RATES...
WITH UPWARDS OF 2 INCHES PER HOUR FROM THE ONE THAT WENT THROUGH THE
ROCHESTER AREA LATE LAST EVENING. TO THE WEST...ANOTHER ZONE OF 1.5-
1.8 INCH PRECIPITABLE WATER WAS PRESENT OVER FAR WESTERN MN...AHEAD
OF THE DAKOTAS UPPER TROUGH AND SOUTHEAST SOUTH DAKOTA SHORTWAVE.
DPVA FROM THESE FEATURES ACTING ON THE MOISTURE RESULTING IN
ISOLATED SHOWER AND STORM ACTIVITY IN FAR WESTERN MN TOO.
THE UPPER TROUGH FROM LAKE WINNIPEG INTO THE DAKOTAS REMAINS ON
TRACK TO MOVE INTO THE FORECAST AREA TONIGHT. PRETTY MUCH ALL DAY
TODAY THROUGH THE EVENING HOURS THE FORECAST AREA IS UNDER FALLING
500MB HEIGHTS. COMBINE THIS WITH A SERIES OF SHORTWAVES COMING
THROUGH FROM THE TROUGH SUCH AS THAT ONE IN SOUTHEAST SOUTH
DAKOTA...THE 1.5-1.8 INCH PRECIPITABLE WATER AIRMASS IN PLACE...AND
DAYTIME HEATING TO ADD EVEN MORE INSTABILITY...RESULTS IN A VERY
FAVORABLE SETUP FOR CONVECTION. THE MAJORITY OF THE FORECAST AREA
SHOULD SEE RAIN OVER THE NEXT 18 HOURS...WITH CORRIDORS OF HEAVIER
RAIN POSSIBLE DUE TO THE HIGH PRECIPITABLE WATER VALUES.
SPECIFICALLY TIMING THE WET AND DRY PERIODS IS VERY PROBLEMATIC...
BUT IN GENERAL IT SEEMS AS IF THERE COULD BE A DRY PERIOD AROUND MID-
MORNING. THIS WOULD CORRELATE WITH THE WEAKENING OF THE LOW LEVEL
JET AND A PERIOD OF SUBSIDENCE BETWEEN THE DEPARTING LA CROSSE
SHORTWAVE AND THE OTHER SHORTWAVE COMING IN FROM THE SIOUX FALLS.
WELL SEE. THE AFTERNOON INTO THE EARLY EVENING HOURS CERTAINLY BODE
WELL FOR CONVECTION WITH THE DAYTIME INSTABILITY HELP...THUS HIGHEST
CHANCES ARE CENTERED THEN. EVEN DURING THIS TIME FRAME...THERE COULD
BE 2-3 HOUR BREAKS BETWEEN ROUNDS OF CONVECTION. ANOTHER SPECIFIC
NOTE...IT WOULD APPEAR THE SOUTHEAST END OF THE FORECAST AREA MAY
NOT GET HIT WITH MUCH CONVECTION UNTIL LATE AFTERNOON OR THE EVENING
HOURS.
LOOK FOR THE CONVECTION TO PUSH OFF TO THE EAST LATE THIS
EVENING THROUGH THE OVERNIGHT HOURS...DUE TO A COMBINATION OF
SUBSIDENCE WORKING IN FROM THE WEST WITH THE TROUGH MOVING IN
PLACE...AS WELL AS LOSS OF DAYTIME HEATING DIMINISHING INSTABILITY.
A COLD FRONTAL PASSAGE LOOKS TO OCCUR AS WELL TONIGHT TO AID IN THE
DIMINISHING TREND.
REGARDING SEVERE WEATHER POTENTIAL...LOOKING AT SHEAR...WE MAY
NEED TO WATCH THE LATE AFTERNOON AND EVENING HOURS. AT 00Z...THE 0-
3KM SHEAR CLIMBS TO 25 KT AROUND I-90 AND 30-35 KT IN NORTHEAST
IOWA. IF CONVECTION EXISTS INTO THESE REGIONS...THEY MAY HAVE
SOME SEVERE WIND POTENTIAL. OTHERWISE...WARM CLOUD DEPTHS UPWARDS OF
3000-3500 METERS WILL RESULT IN HEAVY RAIN AS THE MAIN CONCERN. HAVE
NOT ISSUED ANY FLASH FLOOD WATCH GIVEN ANTECEDENT DRY
CONDITIONS...HOWEVER...LOCALIZED FLOOD ADVISORIES OR WARNINGS MAY
BE NEEDED...ESPECIALLY IN URBAN AREAS WHICH CANNOT HANDLE
HIGHER RAINFALL RATES.
THE CONVECTION AROUND TODAY MAKES FOR A TRICKY HIGH TEMPERATURE
FORECAST. 925MB TEMPS CLIMBING TO 19-22C ON AN INCREASING SOUTHWEST
WIND COULD ALLOW FOR HIGHS OF 80-85 UNDER THE FULL SUN.
HOWEVER...HAVE TO HOLD THESE BACK AS MUCH AS 5 DEGREES OR SO TO
ACCOUNT FOR CONVECTION. WARMEST READINGS ARE LIKELY IN THE SOUTHEAST
END WITH THE LONGEST DRY PERIOD EXPECTED. LOWS TONIGHT EXPECTED ON
THE MILD SIDE AGAIN WITH THE COLD FRONTAL PASSAGE MAKING THE BIGGER
IMPACT TO LOWERING TEMPERATURES.
WITH THE PRECIPITATION ENDING DURING THE NIGHT TIME HOURS...FOG
POTENTIAL NEEDS TO BE CONSIDERED. HOWEVER...IT APPEARS THERE SHOULD
BE A DECENT WEST TO NORTHWEST BREEZE IN THE WAKE OF THE COLD FRONTAL
PASSAGE TO KEEP THE AIR MIXED...PREVENTING FOG FORMATION.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 324 AM CDT MON AUG 18 2014
TUESDAY INTO TUESDAY NIGHT...MODELS TAKE THEIR SWEET TIME IN GETTING
THE UPPER TROUGH OUT OF THE REGION. HOWEVER...IT DOES LOOK TO GET A
DECENT PUSH EAST LATE TUESDAY NIGHT...RESPONDING TO UPPER RIDGING
BEING FORCED TO BUILD UP OVER THE DAKOTAS INTO MN. WHATS
INTERESTING DURING THIS TIME PERIOD IS SUGGESTIONS OF A SECONDARY
COLD FRONT DROPPING SOUTH THROUGH THE AREA DURING THE AFTERNOON AND
EVENING...CONNECTED WITH ANOTHER SHORTWAVE COMING THROUGH THE
TROUGH. HAVE MAINTAINED SOME PRECIPITATION CHANCES...HIGHEST OVER
NORTH CENTRAL WISCONSIN UNDER THE COOLER AIR ALOFT AND HIGHEST
PRECIPITABLE WATER. MUCH OF THE PRECIPITATION SHOULD END BY LATE
EVENING WITH LOSS OF DAYTIME HEATING AND UPPER TROUGH BEGINNING TO
PULL AWAY. IT SHOULD BE NOTED THE RAINFALL RATES ON TUESDAY DO NOT
LOOK NEARLY AS HIGH TODAY...A RESULT OF THE PRECIPITABLE WATER
VALUES ONLY IN THE 1-1.5 RANGE. LATE TUESDAY NIGHT...WE SHOULD GET A
SURFACE RIDGE OF HIGH PRESSURE TO BUILD INTO THE WESTERN 2/3 OF THE
REGION. SKIES SHOULD CLEAR AND WINDS WILL RELAX WITH THE RIDGE
COMING IN...SETTING UP CONDITIONS FAVORABLE FOR SOME FOG TO FORM.
DETAILS ON THE EXPANSE AND THICKNESS OF THE FOG WILL DEPEND EXACTLY
ON THE TIMING OF THE RIDGE COMING IN. DESPITE THE COLD FRONTAL
PASSAGE...925MB TEMPS ARE PROGGED PRETTY SIMILAR ON TUESDAY TO
TODAY. THE SOUTHERN FORECAST AREA SHOULD BE WARMEST GIVEN BETTER
MIXING POTENTIAL.
FOR WEDNESDAY INTO THURSDAY...MODELS BRING THAT UPPER RIDGING OVER
MN INTO THE FORECAST AREA. IT WOULD APPEAR ENOUGH SUBSIDENCE SHOULD
BE IN PLACE PRIOR TO THE RIDGE BUILDING IN TO YIELD A DRY DAY
WEDNESDAY. ADDITIONALLY...THE MAIN WARM FRONTAL BOUNDARY LOOKS TO BE
WELL TO THE SOUTH...ONLY NEAR THE MISSOURI/IOWA BORDER AT 00Z
THURSDAY. HOWEVER...THIS BOUNDARY LOOKS TO SURGE NORTHWARD TOWARDS
THE FORECAST AREA WEDNESDAY NIGHT...AND POSSIBLY COMPLETELY THROUGH
ON THURSDAY. A DECENT PUSH OF 850MB MOISTURE TRANSPORT INTO THE
BOUNDARY WILL INITIATE ELEVATED CONVECTION OVER THE SOUTHWEST
2/3 OF THE AREA. AGAIN HEAVY RAIN LOOKS TO BE A BIG CONCERN AS
PRECIPITABLE WATER CLIMBS BACK UP TOWARDS 2 INCHES...ALONG WITH A
FEED OF INSTABILITY INTO THE CONVECTION FROM THE LOW LEVEL JET...AND
POTENTIAL TO BE IN THE RIGHT ENTRANCE REGION OF A JET STREAK OVER
LOWER MICHIGAN. RIGHT NOW IT APPEARS THE BOUNDARY SHOULD CONTINUE TO
LIFT NORTHWARD...HELPING TO PREVENT A WIDER FLASH FLOOD THREAT...BUT
NEEDS TO BE WATCHED CLOSELY. ADDITIONALLY...CANNOT RULE OUT SOME
SEVERE WIND POTENTIAL FROM THE CONVECTION. CONVECTION SHOULD
DIMINISH LATE THURSDAY MORNING THROUGH THE AFTERNOON HOURS WITH THE
WEAKENING OF THE LOW LEVEL JET...AND AS CAPPING COMES IN ALOFT.
TEMPERATURES AFTER HOVERING IN THE MID 70S TO LOW 80S THROUGH
WEDNESDAY COULD MAKE A MAJOR BOOST ON THURSDAY. THERE IS POTENTIAL
ACCORDING TO THE 18.00Z ECMWF FOR LOCATIONS ALONG/WEST OF THE MS
RIVER TO GET CLOSE TO 90...ALL DEPENDING ON SUN AND WARM FRONTAL
BOUNDARY TRACK.
FOR THURSDAY NIGHT THROUGH THE WEEKEND...THE 500MB PATTERN FEATURES
UPPER RIDGING TO BEGIN THE PERIOD OVER THE AREA WHILE TROUGHING
EXISTS ACROSS THE PACIFIC NORTHWEST. MODELS ARE IN BETTER AGREEMENT
TODAY THAN YESTERDAY HANDLING THIS TROUGH...AND IT APPEARS SOME
OF THIS TROUGH WILL PUSH EAST INTO THE WEEKEND AND HELP SHIFT THE
RIDGE EASTWARD. THIS TRANSLATES INTO A STORM SYSTEM TO AFFECT THE
REGION FOR FRIDAY THROUGH THE WEEKEND. THE ASSOCIATED WARM FRONT
LOOKS TO LIFT INTO THE REGION ON FRIDAY...WHICH MAY OR MAY NOT
CONVECT DEPENDING ON CAPPING. A COLD FRONTAL PASSAGE COULD OCCUR ON
SATURDAY...FOLLOWED BY A LOW RIDING UP ALONG THE FRONT ON SUNDAY.
CONVECTION IS EASILY POSSIBLE ON BOTH OF THESE FEATURES.
THEREFORE...CHANCES OF SHOWERS AND THUNDERSTORMS LITTER MUCH OF THE
EXTENDED. PRIOR TO THE COLD FRONTAL PASSAGE...925MB TEMPS LOOK TO
RANGE FROM 22-26C...SUPPORTIVE OF 80S TO POSSIBLY 90...DEPENDING ON
AMOUNT OF SUN. AIRMASS APPEARS HUMID TOO. COOLER AIR THEN FILTERS
IN FOR SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1256 PM CDT MON AUG 18 2014
TWO SHORT WAVE TROUGHS WILL MOVE THROUGH THE AREA DURING THE NEXT
24 HOURS. EACH OF THESE WILL BE RESPONSIBLE FOR ROUNDS OF SHOWERS
AND THUNDERSTORMS AT THE TAF SITES. THE FIRST ROUND LOOKS TO
AFFECT THE TAF SITES BETWEEN 18.19Z AND 18.23Z...AND THEN ANOTHER
ROUND BETWEEN 19.01Z AND 19.04Z. CEILINGS WILL BE IN THE 2500 TO
3500 FOOT RANGE THROUGH 19.08Z...AND THEN BECOME LIFR/IFR THROUGH
19.15Z...AND THEN MVFR AGAIN. A FEW OF THE NAM AND SREF SOLUTIONS
ARE INICATING THAT THERE COULD BE THE POTENTIAL FOR SOME DENSE FOG
TONIGHT. HOWEVER WITH 15 TO 25 KNOTS ABOVE 950 MB...THINKING THAT
THIS MAY JUST END UP BEING MORE STRATUS THAN FOG. HOWEVER...STILL
WENT WITH MVFR FOG.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP