Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/11/13
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
125 PM PDT MON SEP 9 2013
.SYNOPSIS...
A WEAK LOW PRESSURE TROUGH PARKED OVER THE SOUTHWEST WILL BRING
SLIGHT COOLING...BUT ALSO KEEP THE CHANCE FOR SHOWERS AND
THUNDERSTORMS OVER THE MOUNTAINS AND DESERTS THROUGH MIDWEEK. A
SHALLOW MARINE LAYER WILL KEEP THE COASTAL AREAS COOLER...WITH AREAS
OF LOW CLOUDS AND FOG EXTENDING INTO THE WESTERN VALLEYS. TOWARD THE
END OF THE WEEK...A RIDGE OF HIGH PRESSURE BUILDING IN FROM THE WEST
WILL BRING WARMER WEATHER AND LESS MARINE CLOUDS.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
CUMULUS CLOUDS WERE BUBBLING OVER THE MOUNTAINS EARLY THIS
AFTERNOON...BUT AS OF 115 PM PDT...RADAR DID NOT INDICATE ANY
RAINFALL. THE CLOUDS WERE DRIFTING SOUTH WITH THE UPPER WINDS.
TEMPERATURES AT NOON WERE RUNNING 2 TO 6 DEGREES LOWER THAN
YESTERDAY. SFC PRESSURE GRADIENTS WERE TRENDING A BIT BETTER ONSHORE
TO THE LOWER DESERTS THAN YESTERDAY AS WELL.
MAIN CONCERN AGAIN TODAY AND FOR THE NEXT COUPLE OF DAYS WILL BE
THUNDERSTORMS. MOISTURE AND INSTABILITY LOOK SUFFICIENT FOR
DEVELOPMENT THIS AFTERNOON OVER THE ELEVATED TERRAIN DUE TO HEATING.
MODELS KEEP THE PRECIP THREAT MAINLY ALONG AND EAST OF THE MOUNTAINS
UNDER NORTHERLY FLOW ALOFT. GPS SENSORS OVER OUR LOWER DESERTS ARE
HOLDING NEAR 1.5 INCH OF PW.
ONCE THEY FIRE...THUNDERSTORMS MAY NOT END WITH DAYTIME HEATING.
SIMILAR TO LAST NIGHT...NOCTURNAL THUNDERSTORMS WILL BE POSSIBLE.
WATER VAPOR IMAGERY AT 19Z SHOWED A NARROW STRIP OF DARKENING FROM
NW OF KLAS...TO NEAR BANNING WHICH MAY MARK A WEAK UPPER-LEVEL
DISTURBANCE THAT THE NAM12 ROTATES AROUND THE WEST SIDE IF AN UPPER
LOW CENTERED NEAR BLYTHE OVERNIGHT. GIVEN THE FORECAST MID-LEVEL
INSTABILITY AND LATEST HRRR RUN...AN AREA OF CONVECTION COULD DROP
SW INTO THE COACHELLA VALLEY...SAN DIEGO COUNTY DESERTS...HIGH
DESERTS...AND ADJACENT MOUNTAINS THIS EVENING AND OVERNIGHT.
LOCALIZED FLASH FLOODING IS POSSIBLE...BUT GIVEN THE FLOW ALOFT AND
THE LOWER PWS...THE THREAT DOES NOT LOOK GREAT ENOUGH TO WARRANT A
FFA AT THIS TIME.
ALONG THE COAST...MARINE CLOUDS/STRATUS SHOULD REDEVELOP OVERNIGHT
AND SPREAD INTO THE WESTERN VALLEYS. THE SHALLOW MARINE LAYER WILL
KEEP COASTAL AREAS COOLER THAN THE PAST FEW DAYS. HOWEVER...
INLAND...ABOVE THE SHALLOW MARINE LAYER...IT WILL REMAIN QUITE WARM.
HIGH PRESSURE OVER THE GREAT PLAINS THIS AFTERNOON WILL DRIFT
EASTWARD...WHILE A WEAK LOW PRESSURE TROUGH REMAINS STATIONARY
ACROSS THE WEST. GLOBAL MODELS SHOW THE PATTERN MORPHING INTO A REX
BLOCK WITH A WEAK UPPER LOW HOLDING OVER THE SW THROUGH AT LEAST
THU. HEIGHTS DO GRADUALLY RISE OVER SOCAL AFTER MIDWEEK WITH SOME
DRYING AND WARMING. IN THE MEANTIME...LINGERING MOISTURE AND
INSTABILITY UNDER THE UPPER LOW WILL CONTINUE A THREAT OF
THUNDERSTORMS...EVEN NOCTURNALLY...AND MAINLY ALONG AND EAST OF THE
MOUNTAINS.
ONCE THE UPPER LOW FINALLY DEPARTS TO THE NE...HIGH PRESSURE BUILDS
IN ALOFT WITH A CENTER OVER/NEAR SOCAL. THIS SHOULD RESULT IN VERY
WARM WEATHER ALL THE WAY TO THE COAST AGAIN NEXT WEEKEND.
&&
.AVIATION...
092000Z...THIS EVENING...LOW CLOUDS WILL PUSH ASHORE 10 TO 15
MILES...FIRST REACHING THE COASTAL AIRPORTS BETWEEN 10/0200-0500Z
WITH BASES 900 FT MSL AND TOPS TO AROUND 1500 FT MSL. SNA WILL
BECOME BKN/OVC LATER IN THE NIGHT...AROUND 10/0800Z. VIS REDUCED
LOCALLY TO 2-5 SM EXPECTED WHERE LOW CLOUDS INTERSECT TERRAIN. LOW
CLOUDS AND FOG WILL ERODE TO THE COAST BETWEEN 10/1500Z-1700Z.
MOUNTAINS/DESERTS...ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED
ON THE MOUNTAIN RIDGETOPS AGAIN BETWEEN 09/2100-10/0600Z THIS
AFTERNOON INTO THE EARLY NIGHT. SOME OF THESE STORMS WILL MOVE
SOUTHWARD AND INTO THE COACHELLA VALLEY. BASES WILL BE AROUND 8000
FEET ASL WITH TOPS TO 40000 FEET. LOCAL VIS REDUCED IN +TSRA TO 2SM
AND GUSTY VARIABLE WINDS TO 40 MPH POSSIBLE AROUND STORMS.
OTHERWISE...SCATTERED TO BROKEN CLOUDS AOA 12000 FEET THROUGH
TONIGHT.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...JAD
AVIATION/MARINE...JT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
400 PM MDT MON SEP 9 2013
.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 400 PM MDT MON SEP 9 2013
EXCEPTIONALLY WET PERIOD CONTINUES WITH WIDESPREAD PRECIPITATION
OCCURRING ACROSS BOTH CO AND UT WITH THIS TREND CONTINUING. WATER
VAPOR IMAGERY CURRENTLY SHOWING ANOMALOUS AMOUNTS OF MOISTURE
STREAMING UP FROM THE SOUTH WHILE A DEFORMATION AXIS HAS SET UP
OVER NEVADA INTO NRN UTAH. THIS AXIS IS ALLOWING MOISTURE AND
IMPULSES TO CONTINUE STREAMING INTO OUR AREA. LATEST GUIDANCE TO
INCLUDE THE NAM...RAP AND HRRR SHOW PRECIP CONTINUING THROUGH
TONIGHT AND THEN A RELATIVE LULL BEFORE ANOTHER WAVE CAUSES PRECIP
AGAIN DURING THE MORNING HOURS TOMORROW. WITH PLENTY OF RAIN
HAVING ALREADY FALLEN AND MORE ON THE WAY...EXTENDED THE FLASH
FLOOD WATCH THROUGH TUESDAY NIGHT AND ALSO ADDED THE UNCOMPAGHRE
AND ROAN/TAVAPUTS PLATEAUS SINCE THEY SAW THE BULK OF PRECIP
TODAY. SO FAR ONLY A FEW AREAS (PORTIONS OF ARCHES AND CANYONLANDS
NATIONAL PARK) HAVE REPORTED FLOODING DUE TO THE MAINLY STRATIFORM
NATURE OF THE PRECIP THOUGH A FEW EMBEDDED STORMS HAVE FIRED THIS
AFTERNOON. THE BIGGEST CONCERN HAS BEEN...AND CONTINUES TO
BE...SERN UTAH DUE TO THE SLOT CANYON AND DESERT TERRAIN. LOTS OF
CLOUDS HAVE INHIBITED CONVECTION SO FAR TODAY THOUGH VIS IMAGERY
DOES SHOW SOME BREAKS STARTING TO FORM. WILL ALERT NEXT SHIFTS TO
KEEP AN EYE ON AREA. MOST TEMPS ARE RUNNING ABOUT 5 TO 10 DEGREES
COOLER THAN NORMAL DUE TO RAINFALL AND CLOUDS.
OVERNIGHT...SOME MODELS DEPICT MORE STEADY PRECIP TO
CONTINUE...ESPECIALLY FOR THE ABAJOS...LA SALS AND
UNCOMPAGHRE/ROAN/TAVAPUTS PLATEAUS. OTHER MODELS SHOW MORE OF A
LULL. KEPT PRECIP IN FORECAST AS MOISTURE WILL CONTINUE TO STREAM
OVERHEAD AND ANY WEAK DISTURBANCE/IMPULSE WILL CREATE SHOWERS. FOR
TOMORROW THOUGH...MORE IMPULSES WILL CONTINUE TO MOVE OVER THE CWA
WITH WHAT APPEARS TO BE A SIGNIFICANT IMPULSE MOVING INTO THE 4
CORNERS BY 7AM AND THEN SPREADING NWRD BY NOON. FOR TUESDAY
THEN...ANOTHER DAY LIKE TODAY...CLOUDS...RAIN...COOL TEMPERATURES
WITH INCREASED FLOODING CONCERNS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 400 PM MDT MON SEP 9 2013
THE MAIN STORM TRACK WITH THE STRONGER WESTERLIES WILL REMAIN WELL
TO THE NORTH OF THE INTERMOUNTAIN WEST THROUGH THIS EXTENDED PERIOD.
BY WEDNESDAY STRONG TROUGHING INTO THE GREAT LAKES REGION AND INTO
THE GULF OF ALASKA LEAVES AN AMPLIFIED RIDGE OVER THE NORTHERN US
AND CANADIAN ROCKIES. THIS NORTHERN RIDGE WILL LEAD TO A REX PATTERN
DUE TO AN AREA OF LOW PRESSURE THAT GETS CUT OFF....AND WILL WOBBLE
AROUND THE GREAT BASIN. THIS LOW WILL BE HELD FROM MOVING WEST TO
EAST BY THE SUBTROPICAL HIGH OVER THE SOUTHEAST STATES AND PACIFIC
HIGH PRESSURE BUILDING TOWARD THE WEST COAST. THIS PATTERN WILL BE
STATIC THROUGH AT LEAST THURSDAY AFTER WHICH MEDIUM RANGE MODELS
SWING SOME STRONGER ENERGY INTO WESTERN CANADA...BREAKING THE REX
BLOCK...AND ALLOWING THE GREAT BASIN LOW TO TO BEGIN TO LIFT
NORTHWARD. HOWEVER THERE ARE MODEL CONFLICTS WITH HOW THIS LOW
INTERACTS WITH THE ENERGY BREAKING DOWN THE RIDGE BY LATE IN THE
FORECAST...LEAVING VERY LOW CONFIDENCE IN THE LATTER PERIODS SO
BLENDED MODELS GENERALLY FOLLOWED.
SO TO FOCUS ON THE PERIOD WHEN THE UPPER LOW IS CUTOFF IN THE GREAT
BASIN WEDNESDAY AND THURSDAY. THE MODELS ARE SIMILAR IN LIFTING ONE
LOBE OF STRONGER ENERGY NORTHWARD OUT OF OUR CWA ON
WEDNESDAY...WHILE ROTATING ANOTHER STRONG PIECE ACROSS UTAH ON
THURSDAY. SUBSIDENCE BEHIND THE FIRST WAVE WILL GENERALLY BRING
SOMEWHAT OF A DOWNTURN TO THE PRECIPITATION FOR WEDNESDAY...WITH THE
FAMILIAR PATTERN OF STORMS FOCUSING ON THE TERRAIN BY EARLY
AFTERNOON BEFORE SPREADING INTO THE VALLEYS. ASCENT WILL BEGIN TO
INCREASE SIGNIFICANTLY ON THURSDAY AFTERNOON OVER OUR CWA THURSDAY
WITH THE DYNAMIC TROP DIPPING DOWN TOWARD 400MB WHICH SHOULD ENHANCE
THE INSTABILITY AND BRING AN UPTURN TO STORMS FOR THURSDAY. THE
STRONGER MONSOON PLUME WILL GET DISRUPTED BUT STILL PLENTY OF
MOISTURE AROUND FOR MAKING STORMS. THE DRY CONVEYOR BELT ASSOCIATED
WITH THE PV LOBE MAY ALSO LEAD TO SOME STRONGER STORM DEVELOPMENT.
FROM FRIDAY ONWARD THE LOW WILL HAVE LIFTED NORTH AND EAST OF OUR
AREA BUT A RESIDUAL TROF REMAINS IN PLACE. MOISTURE WILL BEGIN TO
WANE BUT PWATS STILL HOVER AROUND OR JUST ABOVE NORMAL FOR MID
SEPTEMBER AND THIS WILL KEEP A THREAT OF SHOWERS AND THUNDERSTORMS
GOING INTO THE LATE PERIODS. TEMPERATURES THROUGH THE EXTENDED
PERIOD LOOK TO HOVER NEAR THE SEASONAL NORMALS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 400 PM MDT MON SEP 9 2013
RAINFALL CONTINUES THIS AFTERNOON AND FOR MUCH OF THE NEXT 24
HOURS. MVFR AND OCCNL IFR IS EXPECTED THROUGH TOMORROW MORNING
WITH LOW CIGS AND VIS UNDER THE STRONGER SHOWERS AND STORMS THAT
FORM. FOG WILL ALSO BE A CONCERN ESPECIALLY IN THE MORNING DUE TO
AMOUNT OF MOISTURE IN THE AIR. ALL TAF SITES ARE UNDER THE GUN FOR
PRECIP...LOW CLOUDS AND VISIBILITIES THROUGH 00Z TOMORROW.
MOUNTAIN OBSCURATIONS CAN BE EXPECTED OVER ALL HIGHER TERRAIN.
&&
$$
SHORT TERM...TGR
LONG TERM...15
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1004 PM MDT SUN SEP 8 2013
.UPDATE...
ISSUED AT 1004 PM MDT SUN SEP 8 2013
RAP/NAM MODELS CONTINUE TO FOCUS THE HEAVIEST RAINFALL FROM EAST
CENTRAL UTAH TO NORTHWEST COLORADO DURING THE NEXT 12-24
HOURS...ASSOCIATED WITH THE SHEAR AXIS THAT CUTS ACROSS THE SAME
AREA. THIS REMAINS REASONABLE AS SHORT WAVE ENERGY MOVES INTO SRN
UTAH AND SHEARS NORTHEAST. THUS FAR...RAINFALL AMOUNTS HAVE BEEN
"MELLOW" (MOSTLY LESS THAN A QUARTER INCH) EXCEPT FOR CRAIG THAT
HAD A PULSE STORM THAT PRODUCED A HEAVY SHOWER. HOWEVER THIS IS A
SCENARIO WHERE VALUES INCREASE STEADILY AND THE WIDESPREAD NATURE
OF THESE SHOWERS WILL CAUSE ENHANCED FLOWS IN NORMALLY DRY WASHES
AND MOUNTAIN STREAMS. ONE AREA OF CONCERN IS SALT WASH CREEK THAT
FLOWS INTO WOLFE RANCH IN ARCHES NATIONAL PARK.
MONDAY...THE POTENTIAL FOR SIGNIFICANT RAINS SPREADS EAST INTO
THE WESTERN COLORADO MOUNTAINS. THE RAIN COOLED AIR MASS LIMITS
CONVECTIVE POTENTIAL AND HEAVY SHOWER POTENTIAL...BELIEVE THE MAIN
"FLOODING" THREAT WILL BE ENHANCED FLOWS IN DRY WASHES AND STREAMS
AND ROCK/MUD SLIDES. BOOSTED POP/QPF GRIDS TO REFLECT THE LATEST
GUIDANCE AND TRENDS.
UPDATE ISSUED AT 637 PM MDT SUN SEP 8 2013
THE FEATURE TO WATCH FOR THE NEXT 6-12 HOURS IS THE VORT CENTER
STREAMING NORTHWARD OVER NE ARIZONA. AS THIS VORT CENTER MOVES
INTO ERN UTAH LATER TONIGHT...DEFORMATION AXIS BETWEEN DEEP
SUBTROPICAL PLUME ATTACHES ITSELF WITH THE NRN STREAM MONTANA
SHORT WAVE. IN THE RAP MODEL...QPF AMOUNTS ACROSS EAST CENTRAL
UTAH INTO NORTHWEST COLORADO IS SIGNIFICANT WITH SOME AREAS
EXCEEDING AN INCH. THE MOST NOTABLE IS OVER THE TAVAPUTS WITH OVER
3 INCHES OF RAIN. FORECASTING QPF IS TRICKY AND NOT SURE HOW MUCH
IS ATTRIBUTED TO CONVECTIVE PROCESSES WITH THE MODEL. PRUDENT TO
WATCH OBSERVATIONAL TRENDS THIS EVENING.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 351 PM MDT SUN SEP 8 2013
H5 HAND ANALYSIS CENTERED THE SUB-TROPICAL RIDGE OVER THE EASTERN
PLAINS OF KANSAS. UPSTREAM A STRONGER LOW PRESSURE CIRCULATION WAS
CENTERED NEAR THE PANHANDLE OF IDAHO. THE BEST HEIGHT FALLS REMAIN
EAST OF THE LOW AND THE MODEL FORECASTS OF TRACKING THIS FEATURE
ALONG THE US/CANADIAN BORDER OVER THE NEXT 24 TO 48 HOURS LOOKS ON
TRACK. A MORE DIFFUSE...BUT IMPORTANT CIRCULATION CAN ALSO BE SEEN
SPINNING NEAR THE SOCAL/AZ BORDER. THE GRADIENT BETWEEN THE
WESTERN TROUGHS AND EASTERN RIDGE IS PROVIDING A PERSISTENT FETCH
OF DEEP MONSOONAL MOISTURE INTO WESTERN COLORADO AND EASTERN UTAH.
GOES DERIVED IMAGERY SHOWS AN IMPRESSIVE RING OF PWAT EXTENDING
FROM THE HIGH COUNTRY OF MEXICO INTO THE GREAT BASIN...NORTHERN
PLAINS AND BACK INTO THE MO RIVER VALLEY. PWATS ARE GENERALLY 175
- 200 PERCENT OF NORMAL IN THIS RING INCLUDING KGJT.
DYNAMICS...THERMAL INSTABILITY AND THIS MOISTURE BE PRESENT FOR
THE FIRST PART OF THE WEEK OVER OUR CWA WHICH WILL LEAD TO A WET
FORECAST FOR MANY AREAS. TEMPERATURES WILL BE LIMITED BY THE
PRECIPITATION AND CLOUDS AND WILL END UP BELOW NORMAL TO START OUT
THE WEEK.
THE CONVECTION IN OUR CWA IS MOST PROLIFIC NEAR THE THICKER CLOUD
INTERFACE FROM EARLIER TODAY. THESE STORMS ARE MOVING NORTHWARD
AROUND 25 MPH AND SO FAR THE THREAT OF FLOODING OUTSIDE THE WATCH IS
MINIMAL. MORE ORGANIZED CONVECTION IS LOCATED OVER SOUTH CENTRAL UTAH
AND NORTHERN ARIZONA. THIS IS ASSOCIATED WITH ENERGY FROM THE
SOUTHERN LOW AND AN UPPER JET MAXIMA EXTENDING NORTHEAST INTO
WESTERN WYOMING AHEAD OF THE APPROACHING NORTHERN TROF. THIS AREA OF
ENHANCED ASCENT WILL BE SHIFTING EASTWARD THIS EVENING AND
OVERNIGHT. THE MOISTURE PLUME WILL BE SQUEEZED INTO OUR CWA WITH
PWATS LOOKING TO SPIKE AT 1.2-1.4 INCHES NEAR THE UTAH/CO BORDER.
LIFT ASSOCIATED WITH A DEFORMATION/SHEAR AXIS BETWEEN THE TROF AND
THE RIGHT ENTRANCE REGION OF THE UPPER JET ALL LOOK TO BRING
DECENT PRECIPITATION CHANCES TO EASTERN UTAH AND NORTHWEST
COLORADO THROUGH SUNRISE. ISOLATED THUNDERSTORMS WILL BE EMBEDDED
IN THE PRECIPITATION PROVIDING AN HEAVY RAIN THREAT. HOWEVER WITH
A DEEP WARM CLOUD LAYER EVEN THE SHALLOW CONVECTION SHOULD BE
EFFICIENT AT MAKING RAIN.
CONFIDENCE NOT QUITE HIGH ENOUGH TO EXPAND WATCH EAST OR NORTHWARD
INTO TOMORROW. THE PLUME LOOKS TO BE CENTERED FROM THE FOUR CORNERS
TO THE NORTHERN MOUNTAINS BY TOMORROW AFTERNOON...THE NORTHERN END
ARCING WESTWARD BY THE PULL OF THE NORTHERN STREAM TROF MOVING INTO
THE WESTERN DAKOTAS. THIS PLUME LEAVES A THICK CLOUD LAYER OVER MUCH
OF THE CWA...AND SHOULD HELP LIMIT DEEP CONVECTION THROUGH EARLY
AFTERNOON. DRIER AIR LOOKS TO FILTER INTO THE FAR NORTHWEST CWA
BEHIND THE TROF AND MODELS INSIST ON LIMITING THE CONVECTION HERE.
WHILE IN THE 4 CORNERS REGION...ASCENT REMAINS STRONG IN THE
MOISTURE PLUME AS MODELS SHOW ENERGY ARRIVING BY PEAK HEATING TO
HELP BLOSSOM THE CONVECTION. AGAIN EXPECT ANOTHER ROUND OF LATE
NIGHT PRECIPITATION TO LINGER INTO TUESDAY MORNING FAVORED FROM
SOUTHEAST UTAH INTO THE CENTRAL MOUNTAINS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 351 PM MDT SUN SEP 8 2013
THE SUBTROPICAL MOISTURE PLUME WILL CONTINUE TO STREAM DIRECTLY
OVER THE FORECAST AREA AS THE PATTERN BECOMES BLOCKED OVER THE
WESTERN CONUS. THE FIRST SHORTWAVE WILL HAVE MOVED INTO THE
NORTHERN PLAINS BY TUE MORNING...WITH A HIGH PRESSURE RIDGE
REPLACING IT OVER THE PACIFIC NORTHWEST. AS THE NORTHERN BRANCH
SHORTWAVE CONTINUES EAST ON TUE...LOW PRESSURE WILL LINGER OVER
THE DESERT SOUTHWEST AND GREAT BASIN. THE NORTHWEST HIGH AND
SOUTHWEST LOW WILL FORM A REX BLOCK OF SORTS THAT WILL GRADUALLY
EVOLVE BY THE END OF THE WEEK. THE HIGH IS PROGGED TO WEAKEN AND
SHIFT EAST...FORMING A STRONG RIDGE TO OUR EAST...STILL KEEPING A
BLOCK-ISH PATTERN. THE GFS IS QUICKEST IN MOVING OUT THE SOUTHWEST
LOW LATE IN THE WORK WEEK. HOWEVER NATIONAL DISCUSSIONS PREFER A
SLOWER SOLUTION. WITH A SOUTHWEST LOW IN PLACE FOR MOST OF THE
LATE SUMMER...I PREFER THE SLOWER SOLUTION AS WELL. THEREFORE WILL
GENERALLY FOLLOW THE ECMWF FOR THIS FORECAST.
THAT SAID...MADE FEW CHANGES TO THE FORECAST. THE LARGER SCALE
PATTERN AS DESCRIBED ABOVE KEEPS THE THE MOISTURE PLUME PRETTY
MUCH OVERHEAD. THERE ARE SOME NUANCES THOUGH THAT MAY DETERMINE
JUST HOW WET WE WILL REMAIN. ON TUE/TUE NIGHT...THE UPPER LOW
CENTER IS PROGGED TO MOVE NORTHWARD FROM SOUTHWEST AZ TO THE
AZ/NV/UT TRIPLE POINT. AT THE LOWER LEVELS...THE RESULTING
EASTERLY FLOW OVER OUR FORECAST AREA CAN HAVE A SUPPRESSING
INFLUENCE ON PRECIPITATION. HOWEVER DEEP MOISTURE WILL CONTINUE TO
BE IN PLACE. AND WITH THE LOW JUST TO OUR WEST...WE SHOULD SEE
SOME ENHANCED INSTABILITY DUE TO ITS PROXIMITY. THEN ACCORDING TO
THE EC...THE LOW STALLS OVER SOUTHWEST UT THROUGH THE END OF THE
WEEK. MODELS INDICATE THAT A WAVE WILL ROTATE OFF THE LOW AND
SWEEP OVER OUR NORTHWEST CORNER ON WED OR THU. CONFIDENCE IN THE
DETAILS IS LACKING ON THIS FEATURE...BUT STILL KEPT POPS
RELATIVELY HIGH. A SLIGHT DRYING IS PROGGED BY LATE IN THE
WEEK...AND BY EARLY NEXT WEEK EVEN THE EC MOVES THE LOW TO THE
NORTHEAST.
TEMPERATURES WILL REMAIN ON THE COOL SIDE...ESPECIALLY COMPARED
TO THE VERY WARM CONDITIONS WE HAVE SEEN RECENTLY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1004 PM MDT SUN SEP 8 2013
WIDESPREAD -SHRA WITH LOCAL VIS BLO 3SM +SHRA BR DURING THE NEXT
24 HOURS. AREAS OF IFR CIGS/VIS AT MOUNTAIN TAF SITES AND
AIRFIELDS. MOUNTAIN TOPS WILL BE FREQUENTLY OBSCURED. ISOLATED
THUNDERSTORMS NORTH IF I-70 WITH SCATTERED THUNDERSTORMS
SOUTH...WITH ANY THUNDERSTORMS HAVING THE POTENTIAL PRODUCING
HEAVY RAIN SHOWERS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR COZ020-021.
UT...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR UTZ022-025-027>029.
&&
$$
UPDATE...PF
SHORT TERM...15
LONG TERM...EH
AVIATION...PF
AREA FORECAST DISCUSSION
NWS ALBANY NY
1038 PM EDT TUE SEP 10 2013
.SYNOPSIS...
IN THE WAKE OF A WARM FRONT...CLOUDS WILL CONTINUE TO
BREAK UP OVER THE REGION THIS EVENING WITH MILDER AND MUGGY WEATHER
IN PLACE. HOT TEMPERATURES ARE EXPECTED TOMORROW WITH PARTIAL
SUNSHINE...HUMID CONDITIONS...AND A CHANCE FOR A SHOWER OR
THUNDERSTORM. A STRONG COLD FRONT...ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS...WILL MOVE ACROSS THE REGION THURSDAY
USHERING IN A MUCH COOLER AND LESS HUMID AUTUMN AIR MASS FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 1030 PM EDT...MAINLY CLEAR SKIES AND MUGGY CONDITIONS ACROSS
THE REGION. THERE HAS BEEN AN INCREASE IN LOW CLOUDS/FOG PER THE
11U-3.9U ENHANCED IR SATELLITE IMAGERY THIS EVENING COMING DOWN THE
CHAMPLAIN VALLEY AND ADDITIONAL FOG/STRATUS ALONG WITH HAZE IS
EXPECTED OVERNIGHT. HAVE RAISED OVERNIGHT LOWS A COUPLE OF DEGREES
IN SEVERAL LOCATIONS...EXCEPT FOR LAKE GEORGE AND GLENS FALLS
REGIONS WHERE WE LOWERED THEM A BIT MORE PER OBSERVATIONS AND
MESONET OBS.
00Z SOUNDINGS WERE QUITE UNSTABLE IN THE MID LEVELS BUT WITH A LACK
OF A TRIGGER IN THE H2O VAPOR AND HOURLY RUC ANALYSIS...CONTINUED
WITH A DRY FORECAST.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
OUR REGION WILL FIRMLY BE IN THE WARM SECTOR TOMORROW. AFTER ANY
MORNING FOG BREAKS UP...PARTIAL SUNSHINE ALONG WITH 850 HPA TEMPS
OF AROUND 20 DEGREES C WILL YIELD MAX TEMPS IN VALLEY AREAS TO
REACH AROUND 90 DEGREES...WITH 80S ACROSS THE HIGH TERRAIN.
THERE WON/T BE MUCH OF A LARGE SCALE FORCING MECHANISM FOR
SHOWER/THUNDERSTORM DEVELOPMENT TOMORROW...BUT THERE STILL
PROBABLY WILL BE ISOLD TO SCT THUNDERSTORMS DURING THE AFTN AND
EVENING HOURS THANKS TO A PRE FRONTAL TROUGH AND/OR TERRAIN
FORCING. WITH THE WARM AND MUGGY AIR MASS IN PLACE...INSTABILITY
WILL BE HIGH /SBCAPE VALUES ARE PROJECTED TO BE WELL OVER 2000
J/KG/ AND 0-6 KM BULK SHEAR VALUES OF 20-35 KTS LOOK TO BE MORE
THAN SUFFICIENT FOR STORMS TO DEVELOP AND ORGANIZE. SPC HAS PLACED
MUCH OF OUR AREA IN A SLIGHT RISK FOR SVR STORMS AND WE WILL
LIKELY NEED TO MONITOR ANY CONVECTION VERY CLOSELY. DAMAGING WINDS
WOULD BE THE PRIMARY THREAT WITH ANY STORMS. IN ADDITION...HIGH
PWATS/DEWPOINTS WILL ALLOW FOR HVR DOWNPOURS WITHIN ANY T-STORM.
THE THREAT FOR CONVECTION WILL CONTINUE INTO WED NIGHT AS AN
UPSTREAM TROUGH OVER THE GREAT LAKES AND ASSOCIATED SFC COLD FRONT
BEGINS TO HEAD TOWARDS OUR AREA. IT WILL REMAIN MUGGY AND WARM ALL
NIGHT WITH MINS IN THE MID 60S TO NEAR 70...STICKY
CONDITIONS...AND A MOSTLY CLOUDY SKY. THE MAIN THREAT WILL BE ACROSS
THE FAR NORTHWESTERN PART OF THE CWA.
ON THURSDAY INTO THURSDAY NIGHT...THE COLD FRONT WILL BE MOVING
ACROSS OUR AREA...PROVIDING PLENTY OF FORCING FOR LIFT.
INSTABILITY WON/T BE AS ROBUST AS WEDNESDAY THANKS TO MORE CLOUD
COVER...BUT THE STRONG FORCING SHOULD BE ENOUGH TO ALLOW FOR A FEW
LINES OF SHOWERS AND THUNDERSTORMS TO MOVE FROM WEST TO EAST
ACROSS THE AREA. WE WILL GO WITH LIKELY POPS FOR
SHOWERS/THUNDERSTORMS FOR THURSDAY INTO THURSDAY EVENING. SPC HAS
A PORTION OF OUR AREA IN SLIGHT RISK FOR SVR STORMS AGAIN ON
THURSDAY AS WELL. POPS WILL LOWER THURSDAY NIGHT FROM WEST TO EAST
WITH THE PASSAGE OF THE SFC BOUNDARY...WHICH WILL START TO BRING
LESS HUMID AIR INTO THE REGION. TEMPS ON THURSDAY LOOK TO BE IN
THE LOW 80S FOR VALLEY AREAS...WITH MINS IN THE 50S AND 60S FOR
THURS NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A RATHER PROGRESSIVE AND AMPLIFIED PATTERN IS EXPECTED FOR THE LONG
TERM PORTION OF THIS FORECAST AS SEVERAL PERTURBATIONS WITHIN THE
NORTHWEST FLOW REGIME WILL IMPACT OUR REGION.
WE BEGIN WITH FRIDAY AS THE MAIN COLD FRONT AND MOISTURE IS EXPECTED
TO BE EAST OF THE REGION AS WE ARE LEFT WITH A CYCLONIC
FLOW/EMBEDDED UPPER LOW OVER THE EASTERN GREAT LAKES AND NEW
ENGLAND. AS THOSE H850 TEMPS DROP BACK INTO THE LOWER SINGLE
DIGITS...THIS WILL ALLOW FOR LAKE CONTRIBUTIONS TO INCREASE AS WELL
AS THE CHC-SCT SHOWERS MAINLY ACROSS THE HIGHER TERRAIN. AS
CONSIDERABLE CLOUD COVER IS EXPECTED AND MAINLY TERRAIN BASED...WE
WILL SEE HIGH TEMPERATURES MUCH COOLER WITH MAINLY 60S...SOME 50S
FOR THE HIGHER TERRAIN AND ACROSS THE ADIRONDACKS.
THE LOSS OF DIURNAL HEATING WILL RESULT IN A DECREASE IN CLOUDS AND
SHOWERS FRIDAY EVENING. HOWEVER...THE MAIN UPPER LOW IS EXPECTED TO
REMAIN RATHER SLOW MOVING PER THE GLOBAL MODEL CONSENSUS WHICH WILL
SET THE STAGE FOR ANOTHER ROUND OF TERRAIN BASED CLOUD COVER DURING
SATURDAY. THERE IS SOME QUESTION ON JUST HOW MUCH INSTABILITY WILL
BE AROUND FOR SHOWERS AS WE WILL KEEP POPS JUST BELOW SLIGHT CHANCE
AS TRENDS PER THE DPROG/DT FAVOR A DRIER SOLUTION AT THIS TIME.
HIGHS REMAIN BELOW NORMAL WITH MAINLY 50S ACROSS THE TERRAIN AND
LOWER HALF OF THE 60S FOR VALLEY LOCATIONS.
ANOTHER FAST MOVING DISTURBANCE IN THE NORTHWEST FLOW REGIME IS
FORECAST TO APPROACH LATE SUNDAY INTO SUNDAY NIGHT. MOISTURE ALONG
THIS BOUNDARY REMAINS LIMITED BUT LAKE MOISTURE CONTRIBUTION WILL
ADD THE CHANCE FOR SOME SHOWERS MAINLY NORTH AND WEST OF ALBANY.
WINDS ARE EXPECTED TO INCREASE IN THE WAKE OF THE FROPA ON MONDAY AS
THOSE H850 TEMPS DROP BACK INTO THE LOWER SINGLE DIGITS AS A LARGE
CANADIAN HIGH PRESSURE SYSTEM MOVES ACROSS THE GREAT LAKES REGION.
HIGHS WILL REMAIN IN THE 60S.
OVERALL...PCPN AND TEMPS LOOK BELOW NORMAL IN THE EXTEND FORECAST
PERIOD.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
HAZE AND FOG WILL IMPACT FLIGHT CONDITIONS TONIGHT AS MOST OF THE
CLOUDS HAVE EXITED OR DISSIPATED ACROSS THE TAF SITES.
HOWEVER...ENHANCEMENT OF THE IR SATELLITE IMAGERY DOES REVEAL SOME
LOWER CLOUDS ACROSS WESTERN NEW ENGLAND. AS DEWPOINT DEPRESSIONS
CONTINUE TO COLLAPSE...EXPECTATIONS ARE FOR SOME IFR CONDITIONS TO
DEVELOP AND HAVE PLACED THIS INTO THE TAFS OVERNIGHT. A LIGHT
SOUTHERLY WIND WILL PERSIST AND INCREASE THROUGH THE DAYLIGHT
HOURS WEDNESDAY WHICH WILL IMPROVE FLIGHT CONDITIONS TO VFR.
THE CHANCE FOR SOME ISO-SCT CONVECTION INCREASES IN THE AFTERNOON
AND HAVE PLACE VCSH AT THIS TIME.
OUTLOOK...
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THURSDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
FRIDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
FRIDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED ISSUES ARE ANTICIPATED OVER THE NEXT
SEVERAL DAYS.
A WARM FRONT WILL CONTINUE TO MOVE THROUGH THE REGION THIS
EVENING...BRING MUGGY CONDITIONS IN ITS WAKE. THERE WILL BE A THREAT
FOR SHOWERS AND THUNDERSTORMS TOMORROW AND ESPECIALLY AGAIN ON
THURSDAY AS OUR REGION WILL BE IN A WARM AND MUGGY AIR MASS AHEAD OF
AN APPROACHING COLD FRONT. RH VALUES WILL BE HIGH AT NIGHT...NEARLY
100 PERCENT AT TIMES. RH VALUES WILL ONLY DROP TO 50 TO 60 PERCENT
DURING THE DAYTIME HOURS.
&&
.HYDROLOGY...
THERE WILL BE A THREAT FOR SHOWERS AND THUNDERSTORMS OVER THE
SEVERAL DAYS. OUR REGION WILL BE IN A WARM SECTOR TOMORROW BEFORE
A STRONG COLD FRONT MOVES THROUGH ON THURSDAY. PWAT VALUES WILL
BE QUITE HIGH OVER THE NEXT FEW DAYS...WITH PWAT VALUES 1.50 TO
2.00 INCHES. THIS WILL ALLOW FOR ANY SHOWER OR THUNDERSTORM TO BE
CAPABLE OF PRODUCING VERY HEAVY RAINFALL IN A SHORT PERIOD OF
TIME. THUNDERSTORMS LOOK TO BE MOST WIDESPREAD ON THURSDAY AHEAD OF
THE ADVANCING COLD FRONT. THE THREAT FOR HEAVY SHOWERS AND
THUNDERSTORMS WILL END WITH THE PASSAGE OF THE COLD FRONT LATE
THURSDAY...WITH MUCH DRIER AND LESS HUMID WEATHER FOR THE LATE
WEEK PERIOD.
WITHIN ANY SHOWER OR THUNDERSTORM...THERE WILL BE THE POTENTIAL FOR
MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS DUE TO
VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME. WHILE WIDESPREAD MAIN
STEM RIVER FLOODING IS NOT ANTICIPATED OVER THE NEXT FEW
DAYS...THERE WILL BE SOME POTENTIAL FOR FLOODING OF SMALL CREEKS AND
STREAMS DUE TO THE THUNDERSTORM ACTIVITY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/BGM
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...IAA/BGM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
450 AM EDT MON SEP 9 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS UPPER LEVEL RIDGING
EXPANDING EASTWARD FROM THE MIDDLE AND SOUTHERN MS VALLEY TOWARD THE
SE CONUS...WHILE DOWNSTREAM TROUGHING EXTENDS SOUTHWARD TO THE
BAHAMAS FROM JUST OFF THE EASTERN SEABOARD. DEEP LAYER NORTHERLY
FLOW SEEN IN THE KJAX 00Z SOUNDING PROFILE IS DRIVING A LARGE AREA
OF UPPER LEVEL SUBSIDENCE / DRY AIR SOUTHWARD INTO THE FLORIDA
PENINSULA. THE DRY AIR IS NOW ENTRENCHED OVER ABOUT THE ENTIRE
FORECAST AREA...WITH DEEPER MOISTURE SHOVED SOUTH OF EVEN FT MYERS
THIS EARLY MORNING. THE PW VALUE OF THE 00Z SOUNDING AT KTBW WAS
AROUND 1.5" WHICH IS ABOUT AT THE 25TH PERCENTILE OF VALUES FOR
EARLY TO MID SEPTEMBER. THIS LOW VALUE IS REPRESENTATIVE OF THE
DEPTH AND STRENGTH OF THE DRY AIR ALOFT. SHOWER AND THUNDERSTORM
ACTIVITY WILL CONTINUE TO RESPOND TO THIS HOSTILE ENVIRONMENT WITH
LOWER AREAL COVERAGE AND SHORTER CONVECTIVE LIFE-CYCLES.
AT THE SURFACE...A LARGE AREA OF RIDGING EXTENDS DOWN ACROSS THE
EASTERN CONUS TO THE NORTHERN GULF OF MEXICO. OUR POSITION ON THE
SOUTHERN PERIPHERY OF THIS RIDGE IS PROVIDING A LOW LEVEL NE TO E
FLOW PATTERN. REGIONAL RADARS ARE FAIRLY QUIET THIS MORNING OTHER
THAN JUST A FEW ISOLATED CELLS WELL OFFSHORE ALONG THE WESTWARD
PROPAGATING LAND BREEZE BOUNDARY. SIMILAR TO SUNDAY
MORNING...LOWER DEWPOINTS ARE ALLOWING TEMPS TO DROP INTO THE
MID/UPPER 60S FOR NORMALLY COOLER LOCATIONS OF THE NATURE COAST.
JUST A TASTE OF FALL?
WITH THE DRY AIR ALOFT AND GENERAL SYNOPTIC SUPPRESSION...SKIES ARE
MOSTLY CLEAR THIS MORNING...AND WILL REMAIN SO FOR SEVERAL MORE
HOURS UNTIL DIURNAL HEATING CAN BEGIN TO BUBBLE UP A SCT SHALLOW CU
FIELD AFTER 10-11AM.
&&
.SHORT TERM (TODAY THROUGH WEDNESDAY)...
TODAY/TONIGHT...
THE MAIN WEATHER STORY REMAINS THE DRY AIR ALOFT AND ITS INFLUENCE
ON THE DIURNAL CONVECTION. THE DRY AIR ON SUNDAY PREVENTED ALMOST
ALL CONVECTION OVER THE NORTHERN HALF OF THE AREA...AND HAS
PENETRATED EVEN FURTHER SOUTH FOR TODAY. THE MORNING HOURS WILL BE
VERY PLEASANT FOR EARLY SEPTEMBER WITH DRY CONDITIONS UNDER MOSTLY
SUNNY SKIES. SIMILAR TO SUNDAY...THERE IS A SHALLOW MOISTURE LAYER
TRAPPED UNDERNEATH THE DRY AIR...AND DIURNAL HEATING WILL INTERACT
TO BUBBLE UP A SCT SHALLOW CU FIELD BY THE EARLY AFTERNOON.
THE DEEPEST LAYER OF HOSTILE MID LEVEL AIR WILL EXIST OVER THE
CENTRAL AND NORTHERN ZONES ASSOCIATED WITH WHAT THE GFS IS
ADVERTISING AS SOME HEALTHY Q-VECTOR DIVERGENCE AND OVERALL SYNOPTIC
SUPPRESSION. THIS ENVIRONMENT SHOULD SUPPORT ISOLATED STORMS AT
BEST...AND ANY STORMS THAT DO DEVELOP WILL BE SHORT-LIVED AS THEY
QUICKLY INGEST THE HOSTILE MID-LEVEL THETA-E AIR INTO THEIR
CONVECTIVE COLUMNS. SOUTH OF TAMPA BAY ALONG THE SUNCOAST AND
INTERIOR SOUTH-CENTRAL ZONES...THE DRY AIR IS STILL IN PLACE...BUT
NOT QUITE AS DEEP. THE SOUTHERN COASTAL ZONES WILL ALSO SEE THE MOST
DEFINED EASTERLY FLOW TO FOCUS LOW LEVEL CONVERGENCE ALONG THE I-75
CORRIDOR THIS AFTERNOON. IF THE FLOW WAS NOT EASTERLY...THEN WOULD
PROB GO 20-30% ON THE RAIN CHANCES AT BEST...BUT GIVEN THE FAVORABLE
WIND DIRECTION WHICH USUALLY GIVES QUITE HIGH RAIN CHANCES...WILL
FORECAST (30-40%). THESE NUMBERS ARE ABOVE THE STATISTICAL
GUIDANCE...BUT WELL BELOW THE CLIMO RAIN CHANCES FOR THE PARTICULAR
LOW LEVEL WIND REGIME.
ANY WIDELY SCT EVENING STORMS WILL QUICKLY EXIT OUT OVER THE COASTAL
WATERS BY 02-03Z. GRADIENT BEGINS TO TIGHTEN SOMEWHAT OVERNIGHT AS
THE RIDGE TO OUR NORTH DROPS SOUTH AND STRENGTHENS. THE INFLUENCE OF
THIS WILL MAINLY BE FELT OVER THE COASTAL WATERS WITH A NOCTURNAL
EASTERLY WIND SURGE. STILL SEE SOME POTENTIAL TO BRIEFLY DE-COUPLE
OVER THE INTERIOR NATURE COAST BEFORE DAWN. IF THESE AREAS CAN
DE-COUPLE...THEN ANOTHER MORNING WITH LOWS IN THE MID/UPPER 60S IS
LIKELY. WILL HAVE TO WAIT AND SEE IF THE SLIGHT PRESSURE DIFFERENCE
NEAR THE COAST RELATED TO THE NOCTURNAL SURGE WIND SPEED DIVERGENCE
IS ENOUGH TO LOCALLY TIGHTEN THE GRADIENT...AND OVERCOME THE
DE-COUPLING PROCESS. ELSEWHERE FURTHER SOUTH LOWER TO MID 70S WILL
BE COMMON.
TUESDAY/WEDNESDAY...
THE DRY AIR ALOFT IS STILL IN PLACE FOR TUESDAY TO HINDER DEEP
CONVECTION DEVELOPMENT. THE LOW LEVEL FLOW IS DEFINED EASTERLY FOR
ALL ZONES BY THE AFTERNOON HOURS...AND MAY HELP SOMEWHAT TO FOCUS
THE CONVERGENCE. THE FLOW APPEARS TO MUCH TO ALLOW A DEFINED
SEA-BREEZE TO DEVELOP...HOWEVER AT LEAST SOME WEAKENING OF THE
AFTERNOON WINDS ACROSS THE NEAR SHORE WATERS SHOULD ALLOW MODEST
SPEED CONVERGENCE NEAR THE COAST. WITH THIS IN MIND WILL EXPAND THE
30% POPS FOR WIDELY SCT LATE AFTERNOON STORMS NORTHWARD TO MANATEE
COUNTY AND SOUTHERN PORTIONS OF TAMPA BAY. HOWEVER...THIS IS REALLY
JUST A COSMETIC CHANGE TO THE FORECAST...AS ANY STORMS STILL LOOK
"FEW AND FAR BETWEEN". CONVECTION OVER THE NATURE COAST AGAIN LOOKS
ISOLATED AT BEST.
BY WEDNESDAY...A WEAK UPPER LOW FEATURE IS SHOWN BY THE GFS AND
ECMWF TO BEGIN RETROGRADING OVER THE STATE. THIS FEATURE SHOULD
BRING AT LEAST SOME INCREASE IN DEEP LAYER MOISTURE TO CENTRAL AND
SOUTHERN PORTIONS OF THE AREA. CERTAINLY NOT GOING TO MAKE THE
ATMOSPHERE MOIST OVERHEAD...BUT POTENTIALLY NOT QUITE AS HOSTILE TO
DEEP CONVECTION. WILL INCREASE RAIN CHANCES TO 25-35% NORTH AND
35-50% SOUTH. THESE NUMBERS AGREE WELL WITH ECMWF STATISTICAL
GUIDANCE...BUT REMAIN WELL BELOW THE CLIMO RAIN CHANCES ASSOCIATED
WITH EASTERLY FLOW.
&&
.LONG TERM (THURSDAY THROUGH NEXT SUNDAY)...
AN AXIS OF HIGH PRESSURE WILL RESIDE ACROSS THE GULF COASTAL AND
SOUTHEASTERN STATES THU AS A SURFACE TROUGH/TROPICAL WAVE EXITS FL
INTO THE GULF. DURING FRI AND SAT THE SURFACE RIDGE SHIFTS SOUTH/
INTO NORTHERN FL/ IN RESPONSE TO AN UPPER TROUGH WITH A FRONTAL
BOUNDARY THAT SETTLES IN ALONG THE GA/FL LINE. BY SUN THE UPPER
TROUGH MOVES OUT OVER THE ATLANTIC AS IT LIFTS NORTH WITH THE
FRONTAL BOUNDARY DISSIPATING AS HIGH PRESSURE OVER THE EASTERN CONUS
BRIDGES IT.
THE AREA WILL BE UNDER THE INFLUENCE OF EASTERLY FLOW...RELAXED
ENOUGH FOR AFTERNOON SEA BREEZES...WITH ADEQUATE MOISTURE FOR
ISOLATED TO SCATTERED THUNDERSTORMS WITH THE HIGHEST COVERAGE IN THE
AFTERNOONS. THE RAIN CHANCES WILL BE CLOSE TO NORMAL AND GENERALLY
IN THE 30 TO 40/50 PERCENT RANGE...FROM NORTH TO SOUTH.
&&
.MARINE...
LOCAL GRADIENT WILL REMAIN WEAK THROUGH THIS AFTERNOON KEEPING WINDS
AND SEAS LOW. THEREAFTER...HIGH PRESSURE TO OUR NORTH WILL
STRENGTHEN AND PROVIDE FAVORABLE CONDITIONS TO SUPPORT NOCTURNAL AND
MORNING SURGES OF EASTERLY FLOW THAT WILL APPROACH OR REACH
CAUTIONARY LEVELS AT TIMES BEGINNING TONIGHT AND RE-DEVELOPING
TUESDAY NIGHT. THE LOCAL GRADIENT AND RESULTING WINDS WILL AGAIN
RELAX BY THE END OF THE WEEK AS HIGH PRESSURE BUILDS SOUTH OVER THE
EASTERN GULF OF MEXICO.
&&
.AVIATION...
LIMITED AFTERNOON CONVECTION HAS NOW SHIFTED OFFSHORE WITH VFR
PREVAILING FOR THE NEXT 24 HOURS. CAN NOT RULE OUT SOME PATCHY BR
TOWARD SUNRISE AT LAL/PGD BUT WILL LEAVE OUT OF THE TAFS. DRY AIR
MOVING IN MON WITH ONLY VCTS AT PGD/FMY/RSW.
&&
.FIRE WEATHER...
HIGH PRESSURE TO OUR NORTH WILL CONTINUE TO PROVIDE THE REGION WITH
A GENERALLY EASTERLY FLOW THE NEXT SEVERAL DAYS. THE GRADIENT MAY BE
LIGHT ENOUGH TODAY IN ORDER TO ALLOW WINDS TO TURN ONSHORE AT THE
IMMEDIATE COAST IN THE AFTERNOON...HOWEVER FLOW SHOULD THEN BE
STRONG ENOUGH ON TUESDAY AND WEDNESDAY TO PREVENT MUCH OF A
SEA-BREEZE. DRIER LOW LEVEL AIR IS NOW IN PLACE...ESPECIALLY NORTH
OF I-4...HOWEVER EVEN WITH THIS DRIER AIR...RELATIVE HUMIDITY IS
EXPECTED TO REMAIN ABOVE CRITICAL LEVELS. DISPERSION INDICES WILL
HOWEVER BE ON THE HIGH SIDE BOTH THIS AFTERNOON AND TUESDAY
AFTERNOON...WITH THE HIGHEST VALUES TO THE NORTH OF TAMPA BAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 93 75 92 76 / 20 10 20 10
FMY 92 74 92 75 / 40 20 30 20
GIF 92 73 92 73 / 20 10 20 10
SRQ 93 75 92 75 / 20 20 30 20
BKV 93 68 92 69 / 20 10 20 10
SPG 93 78 91 79 / 20 10 20 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
142 PM EDT MON SEP 9 2013
.PREV DISCUSSION...
UPDATE...
/ISSUED 1103 AM EDT MON SEP 9 2013/
FORECAST IS ON TRACK SO ONLY A FEW MINOR CHANGES IN THE UPDATE TO
ACCOUNT FOR HOURLY TRENDS. MAIN UNCERTAINTY THIS AFTERNOON IS IN
TERMS OF PRECIP. HRRR MAY BE OVER DOING CONVECTION TODAY AND IS
TRYING TO DEVELOP ACTIVITY ACROSS EVEN THE ATL METRO AREA BY 17Z
HOWEVER THE OTHER MODELS SUCH AS THE LOCAL WRF ARE VERY LIMITED ON
CONVECTIVE ACTIVITY TODAY. THINK THE BEST CHANCES REMAIN ACROSS
FAR NORTH GEORGIA AND IN PARTICULAR ACROSS NORTHWEST
GEORGIA...CLOSER TO THE SHORTWAVE.
11
SHORT TERM /TODAY THROUGH TONIGHT/...
/ISSUED AT 345 AM EDT MON SEP 9 2013/
ISOLATED SHOWERS CONTINUE TO DEVELOP ACROSS PARTS OF CENTRAL GA
EARLY THIS MORNING AND MAY NEED TO CONTINUE SMALL CHANCE POPS INTO
THE MORNING HOURS. SOME SLIGHT DIFFERENCES BETWEEN THE GFS AND THE
NAM/ECMWF MIX FOR THE SHORT TERM...MAINLY IN THE LOCATION OF THE
DEEPEST MOISTURE. ALL MODELS SHOW A SHORT WAVE OVER TN. THE GFS
HOLDS THE S/W OVER TN/NRN AL WHILE THE NAM/ECMWF BRINGS IT TO THE
NORTHWEST GA BORDER ALONG WITH SOME DEEPER MOISTURE. WITH THE RETURN
OF AN EASTERLY FLOW BRINGING IN ATLANTIC MOISTURE...THE RISK OF
CONVECTION IS SLIGHTLY GREATER THAN SUNDAY WITH A BETTER CHANCE NEAR
THE VICINITY OF THE S/W AND THEREFORE HAVE GONE WITH CHANCE POPS
OVER NORTHWEST GA. CONVECTION SHOULD DISSIPATE AFTER SUNSET. WINDS
WILL BE EASTERLY THROUGH THE SHORT TERM AND THEREFORE EXPECT MAX
TEMPS TODAY TO BE AT OR PERHAPS A DEGREE OR TWO LOWER THAN SUNDAYS
MAX TEMPS.
17
LONG TERM /TUESDAY THROUGH SUNDAY/...
/ISSUED AT 345 AM EDT MON SEP 9 2013/
A WEAKNESS IN THE UPPER RIDGE AND ASSOCIATED MOISTURE WILL GIVE SOME
CHANCES FOR SHOWERS AND THUNDERSTORMS OVER MAINLY FAR N GA TUESDAY
AFTERNOON. NOT SURE THE MODELS HAVE A GOOD HANDLE ON THIS AND THERE
COULD BE SOME CHANCE FOR MEASURABLE PRECIP TUESDAY MORNING. OVERALL
INSTABILITY IS WEAK AND THE PRECIP COULD BE ONLY SHOWERS.
THE SAME WEAKNESS THAT DOES NOT APPEAR TO BE HANDLED VERY WELL BY
THE MODELS AND ASSOCIATED MOISTURE COULD CAUSE SOME SHOWERS AND
THUNDERSTORMS OVER MAINLY FAR N GA ON WEDNESDAY AFTERNOON AND MOST
SO OVER THE NE MOUNTAINS WHERE THE BEST INSTABILITY IS FORECAST.
A COLD FRONT APPROACHES N GA LATE THURSDAY GIVING A CHANCE OF
SHOWERS AND THUNDERSTORMS OVER MAINLY N GA. FRONT EXPECTED TO MOVE
INTO N GA THURSDAY NIGHT/FRIDAY MORNING AND TO S GA SATURDAY
MORNING. THIS WILL CONTINUE THE CHANCE OF SHOWERS AND THUNDERSTORMS
FOR MUCH OF THE AREA ON FRIDAY AND MAINLY FOR CENTRAL GA ON
SATURDAY. MODELS INCONSISTENT WITH MOISTURE RETURN ON SATURDAY NIGHT
AND SUNDAY WITH THE GFS INCREASING SIGNIFICANT MOISTURE MUCH MORE
THAN THE EUROPEAN FROM STRONGER EAST FLOW OFF THE ATLANTIC. DUE TO
THE UNCERTAINTY WILL NEED TO INDICATE SMALL POPS OVER CENTRAL AND
PORTIONS OF N GA FOR SHOWERS ONLY ON SUNDAY.
HIGH TEMPERATURES GENERALLY RUNNING SLIGHTLY ABOVE NORMAL TUESDAY
THROUGH THURSDAY THEN AROUND 5 DEGREES BELOW NORMAL SATURDAY AND
SUNDAY.
BDL
&&
.AVIATION...
18Z UPDATE...
STARTING TO SEE CONVECTION DEVELOP ACROSS NORTH GEORGIA AND
EASTERN ALABAMA. WITH ONLY ABOUT A 20 PERCENT CHANCE OF CONVECTION
AT CSG AND ATL TAF SITES...HAVE OPTED TO LEAVE MENTION OF TSRA OUT
OF TAFS BUT WILL HAVE TO CLOSELY MONITOR TRENDS. STILL EXPECT BEST
CHANCES TO REMAIN NORTH AND WEST OF THE TAF SITES. MODELS ARE
INDICATING SOME LOW CLOUDS ARE POSSIBLE TOMORROW
MORNING...FEW010...BUT CONFIDENCE IS LOW.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON VSBYS AND WIND. HIGH CONFIDENCE ON CIGS EXCEPT
FOR LOW CONFIDENCE TOMORROW MORNING. MEDIUM CONFIDENCE ON
CONVECTION NOT OCCURRING AT ATL.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 66 89 68 / 20 10 10 0
ATLANTA 90 70 88 69 / 20 10 10 5
BLAIRSVILLE 82 64 85 64 / 20 20 20 20
CARTERSVILLE 90 66 89 65 / 20 20 20 5
COLUMBUS 93 71 90 70 / 20 10 5 5
GAINESVILLE 87 68 88 68 / 20 20 20 5
MACON 92 66 90 68 / 20 10 5 5
ROME 91 67 90 66 / 30 20 20 5
PEACHTREE CITY 90 66 88 66 / 20 10 10 5
VIDALIA 91 68 91 69 / 20 10 5 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....39
AVIATION...11
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1249 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL DISSIPATE NORTH OF THE AREA TODAY AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. HIGH PRESSURE WILL THEN PREVAIL
THROUGH THE MIDDLE OF THE WEEK BEFORE A BACKDOOR COLD FRONT DROPS
ACROSS THE AREA FRIDAY AND FRIDAY NIGHT. COOLER HIGH PRESSURE WILL
THEN BUILD INTO THE REGION FROM THE NORTH INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FORECAST IS ON TRACK. A FEW LIGHT SPRINKLES HAVE BEEN DETECTED
BY KCLX...BUT THESE REALLY ARE NOT AMOUNTING TO TOO MUCH.
A VERY WEAK BACKDOOR FRONT MOVING SOUTH ACROSS NORTH CAROLINA WILL
DISSIPATE NORTH OF THE AREA TODAY. LIGHT WINDS WILL BECOME ONSHORE
THIS AFTERNOON AS HIGH PRESSURE BUILDS SOUTH AND A MODEST SEA
BREEZE CIRCULATION TAKES HOLD. A NUMBER OF THE HIGHER RESOLUTION
MODELS INCLUDING THE H3R...4KM NSSL WRF AND RAP ARE SPITTING OUT
ISOLATED SHOWERS/TSTMS ALONG THE SEA BREEZE FOR 1-2 HOURS THIS
AFTERNOON. NOT COMPLETELY CONVINCED ACTIVITY WILL FIRE AS IT
APPEARS THEY MAY BE OVER DEVELOPING THE CUMULUS FIELD ALONG THE
LEADING EDGE OF THE THERMALLY DIRECT CIRCULATION. PLAN TO KEEP THE
FORECAST DRY FOR NOW...ALTHOUGH SOME SMALL...SINGLE DIGIT GRIDDED
POPS WILL BE PLACED ALONG AND AHEAD OF THE SEA BREEZE FOR THE
AFTERNOON HOURS. SHOULD ANY SHOWERS/TSTMS DEVELOP...THEY WILL BE
SHORT LIVED GIVEN THE AMOUNT OF DRY AIR NOTED ALOFT. OVER THE
WATER...AN ISOLATED SHOWER WILL BE POSSIBLE THROUGH LATE THIS
MORNING ALONG A LINGERING LAND BREEZE CIRCULATION THAT IS NOTED
ABOUT 5 NM OFFSHORE.
A DECENT CUMULUS FIELD DEVELOP PRIOR TO NOON...BUT SHOULD CLEAR
OUT FROM EAST-WEST AS THE SEA BREEZE MOVES INLAND. HIGHS WILL FROM
THE LOWER 90S INLAND TO THE MID 80S AT THE BEACHES LOOK ON TRACK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE NORTH
WITH DRY CONDITIONS EXPECTED. JUST A REAL SMALL CHANCE OF A SHOWER
NEAR THE COAST LATE AS A WEAK COASTAL TROUGH ATTEMPTS TO DEVELOP.
OTHERWISE...LOWS SHOULD RANGE FROM THE UPPER 60S INLAND TO THE
MID 70S AROUND THE COAST.
TUESDAY THROUGH THURSDAY...EXPANSIVE UPPER LEVEL RIDGING WILL
PREVAIL OVER THE SOUTHEAST U.S. TUESDAY AND TUESDAY NIGHT...BUT
THEN AN INVERTED UPPER LEVEL TROUGH WILL RETROGRADE TOWARD THE
SOUTHEAST COAST WEDNESDAY AND WEDNESDAY NIGHT CAUSING THE EASTERN
PERIPHERY OF THE RIDGE TO ERODE. A LONGWAVE UPPER LEVEL TROUGH
WILL THEN BEGIN TO BECOME ESTABLISHED OVER THE EASTERN U.S. ON
THURSDAY. MEANWHILE AT THE SURFACE...HIGH PRESSURE WILL BUILD INTO
THE REGION FROM THE NORTH THROUGH WEDNESDAY...WITH THE AXIS OF THE
HIGH SHIFTING SOUTHWARD ACROSS THE AREA ON THURSDAY AS A COLD
FRONT APPROACHES FROM THE NORTHWEST.
STRONG SUBSIDENCE AND A LACK OF DEEP MOISTURE WILL GENERALLY KEEP
RAIN-FREE CONDITIONS IN PLACE. THE EXCEPTION COULD BE ALONG PARTS OF
THE IMMEDIATE SOUTHEAST GEORGIA COAST WHERE ISOLATED CONVECTION
COULD DEVELOP OFFSHORE IN AN AREA OF ENHANCED LOW LEVEL CONVERGENCE
AND SHIFT ONSHORE AT TIMES TUESDAY NIGHT THROUGH THURSDAY.
HIGH TEMPERATURES WILL GENERALLY BE AROUND 90...WITH COOLER
TEMPERATURES ALONG THE IMMEDIATE COAST. RADIATIONAL COOLING WILL BE
SUFFICIENT TO ALLOW TEMPERATURES TO FALL INTO THE UPPER 60S AWAY
FROM THE COAST...WITH A FEW MID 60S POSSIBLE IN WELL SHELTERED
AND/OR LOW LYING AREAS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH THE LONG TERM
PERIOD. A LONGWAVE UPPER LEVEL TROUGH WILL BE THE PREDOMINANT
FEATURE OVER THE EASTERN U.S. THROUGH SATURDAY...BEFORE THE TROUGH
LIFTS OUT AND THE FLOW BECOMES MORE ZONAL LATE IN THE WEEKEND INTO
EARLY NEXT WEEK. AT THE SURFACE...A BACKDOOR COLD FRONT WILL DROP
ACROSS THE AREA FRIDAY INTO FRIDAY NIGHT...THEN STALL OUT JUST SOUTH
OF THE AREA THROUGH THE REMAINDER OF THE LONG TERM PERIOD AS MUCH
COOLER HIGH PRESSURE BUILDS IN FROM THE NORTH.
THERE IS A CHANCE THAT SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE
PASSAGE OF THE COLD FRONT FRIDAY AND FRIDAY NIGHT...AND CONTINUE
INTO SATURDAY ACROSS MUCH OF THE AREA AS THE FRONT STALLS JUST TO
THE SOUTH. PRECIPITATION CHANCES WILL THEN CONTINUE INTO EARLY NEXT
WEEK ACROSS MUCH OF SOUTHEAST GEORGIA WHICH IS IN CLOSER PROXIMITY
TO THE FRONT AND THE DEEPER MOISTURE...WITH SOMEWHAT DRIER
CONDITIONS POSSIBLE FARTHER NORTH INTO PARTS OF SOUTHEAST SOUTH
CAROLINA.
TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH FRIDAY...THEN
COOLER/BELOW TEMPERATURES WILL OCCUR DURING THE REMAINDER OF THE
LONG TERM PERIOD AS A NORTHEAST FLOW DEVELOPS AS HIGH PRESSURE
BUILDS SOUTHWARD INTO THE REGION.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS WITH A GREATER
THAN 30 PERCENT CONFIDENCE AT THIS TIME.
&&
.MARINE...
TODAY AND TONIGHT...HIGH PRESSURE WILL BUILD IN FROM THE NORTH
CAUSING WINDS TO SHIFT TO EASTERLY BUT REMAINING 15 KT OR LESS.
WINDS COULD BACK TO MORE NORTHEAST NEAR THE COAST LATE TONIGHT AS
A WEAK COASTAL TROUGH OF LOW PRESSURE TRIES TO DEVELOP. SIGNIFICANT WAVE
HEIGHTS WILL BE UP TO 3 FT WITHIN 20 NM AND UP TO 4 FT BEYOND 20
NM...DOMINATED BY A 8-9 SECOND E/SE SWELL...AT LEAST THROUGH
TODAY.
TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL BUILD OVER THE
REGION FROM THE NORTH THROUGH WEDNESDAY...MAINTAINING AN ONSHORE
FLOW OVER THE WATERS WITH WIND SPEEDS GENERALLY 15 KT OR LESS. THE
FLOW WILL BECOME MORE SOUTHERLY ON THURSDAY AHEAD OF AN APPROACHING
COLD FRONT...WHICH IS EXPECTED TO DROP ACROSS THE WATERS FRIDAY AND
FRIDAY NIGHT SHIFTING THE WINDS NORTHEAST IN ITS WAKE. A STRONG
NORTHEAST SURGE WILL THEN OCCUR FRIDAY NIGHT AND SATURDAY...LIKELY
RESULTING IN SMALL CRAFT ADVISORY CONDITIONS OVER PORTIONS OF THE
WATERS. SEAS WILL GENERALLY BE NO HIGHER THAN 2-4 FT...GREATEST OVER
THE OUTER GEORGIA WATERS...THROUGH FRIDAY BEFORE INCREASING A COUPLE
OF FEET SATURDAY AS THE STRONG NORTHEAST FLOW DEVELOPS AND THE FETCH
INCREASES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1103 AM EDT MON SEP 9 2013
.UPDATE...
FORECAST IS ON TRACK SO ONLY A FEW MINOR CHANGES IN THE UPDATE TO
ACCOUNT FOR HOURLY TRENDS. MAIN UNCERTAINTY THIS AFTERNOON IS IN
TERMS OF PRECIP. HRRR MAY BE OVER DOING CONVECTION TODAY AND IS
TRYING TO DEVELOP ACTIVITY ACROSS EVEN THE ATL METRO AREA BY 17Z
HOWEVER THE OTHER MODELS SUCH AS THE LOCAL WRF ARE VERY LIMITED ON
CONVECTIVE ACTIVITY TODAY. THINK THE BEST CHANCES REMAIN ACROSS
FAR NORTH GEORGIA AND IN PARTICULAR ACROSS NORTHWEST
GEORGIA...CLOSER TO THE SHORTWAVE.
11
&&
.PREV DISCUSSION...
SHORT TERM /TODAY THROUGH TONIGHT/...
/ISSUED AT 345 AM EDT MON SEP 9 2013/
ISOLATED SHOWERS CONTINUE TO DEVELOP ACROSS PARTS OF CENTRAL GA
EARLY THIS MORNING AND MAY NEED TO CONTINUE SMALL CHANCE POPS INTO
THE MORNING HOURS. SOME SLIGHT DIFFERENCES BETWEEN THE GFS AND THE
NAM/ECMWF MIX FOR THE SHORT TERM...MAINLY IN THE LOCATION OF THE
DEEPEST MOISTURE. ALL MODELS SHOW A SHORT WAVE OVER TN. THE GFS
HOLDS THE S/W OVER TN/NRN AL WHILE THE NAM/ECMWF BRINGS IT TO THE
NORTHWEST GA BORDER ALONG WITH SOME DEEPER MOISTURE. WITH THE RETURN
OF AN EASTERLY FLOW BRINGING IN ATLANTIC MOISTURE...THE RISK OF
CONVECTION IS SLIGHTLY GREATER THAN SUNDAY WITH A BETTER CHANCE NEAR
THE VICINITY OF THE S/W AND THEREFORE HAVE GONE WITH CHANCE POPS
OVER NORTHWEST GA. CONVECTION SHOULD DISSIPATE AFTER SUNSET. WINDS
WILL BE EASTERLY THROUGH THE SHORT TERM AND THEREFORE EXPECT MAX
TEMPS TODAY TO BE AT OR PERHAPS A DEGREE OR TWO LOWER THAN SUNDAYS
MAX TEMPS.
17
LONG TERM /TUESDAY THROUGH SUNDAY/...
/ISSUED AT 345 AM EDT MON SEP 9 2013/
A WEAKNESS IN THE UPPER RIDGE AND ASSOCIATED MOISTURE WILL GIVE SOME
CHANCES FOR SHOWERS AND THUNDERSTORMS OVER MAINLY FAR N GA TUESDAY
AFTERNOON. NOT SURE THE MODELS HAVE A GOOD HANDLE ON THIS AND THERE
COULD BE SOME CHANCE FOR MEASURABLE PRECIP TUESDAY MORNING. OVERALL
INSTABILITY IS WEAK AND THE PRECIP COULD BE ONLY SHOWERS.
THE SAME WEAKNESS THAT DOES NOT APPEAR TO BE HANDLED VERY WELL BY
THE MODELS AND ASSOCIATED MOISTURE COULD CAUSE SOME SHOWERS AND
THUNDERSTORMS OVER MAINLY FAR N GA ON WEDNESDAY AFTERNOON AND MOST
SO OVER THE NE MOUNTAINS WHERE THE BEST INSTABILITY IS FORECAST.
A COLD FRONT APPROACHES N GA LATE THURSDAY GIVING A CHANCE OF
SHOWERS AND THUNDERSTORMS OVER MAINLY N GA. FRONT EXPECTED TO MOVE
INTO N GA THURSDAY NIGHT/FRIDAY MORNING AND TO S GA SATURDAY
MORNING. THIS WILL CONTINUE THE CHANCE OF SHOWERS AND THUNDERSTORMS
FOR MUCH OF THE AREA ON FRIDAY AND MAINLY FOR CENTRAL GA ON
SATURDAY. MODELS INCONSISTENT WITH MOISTURE RETURN ON SATURDAY NIGHT
AND SUNDAY WITH THE GFS INCREASING SIGNIFICANT MOISTURE MUCH MORE
THAN THE EUROPEAN FROM STRONGER EAST FLOW OFF THE ATLANTIC. DUE TO
THE UNCERTAINTY WILL NEED TO INDICATE SMALL POPS OVER CENTRAL AND
PORTIONS OF N GA FOR SHOWERS ONLY ON SUNDAY.
HIGH TEMPERATURES GENERALLY RUNNING SLIGHTLY ABOVE NORMAL TUESDAY
THROUGH THURSDAY THEN AROUND 5 DEGREES BELOW NORMAL SATURDAY AND
SUNDAY.
BDL
AVIATION...
12Z UPDATE...
/ISSUED 730 AM EDT MON SEP 9 2013/
PATCHY LIGHT FOG WILL DISSIPATE BY 14Z LEAVING VFR CONDITIONS ACROSS
THE FORECAST AREA THROUGH THIS EVENING. CHANCES OF TSRA AT THE TAF
SITES THIS AFTERNOON ARE LOW ENOUGH TO LEAVE OUT OF THE TAF FOR NOW.
WINDS ARE NOW NORTHEAST AND THEY SHOULD STAY EASTERLY FOR THE REST
OF THE FORECAST PERIOD WITH SPEEDS LESS THAN 10 KTS.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ALL ELEMENTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 89 66 89 68 / 20 20 10 0
ATLANTA 90 70 88 69 / 20 20 10 0
BLAIRSVILLE 82 64 85 64 / 20 20 20 10
CARTERSVILLE 90 66 89 65 / 20 20 20 10
COLUMBUS 93 71 90 70 / 20 20 10 0
GAINESVILLE 87 68 88 68 / 20 20 10 10
MACON 92 66 90 68 / 20 10 5 0
ROME 91 67 90 66 / 30 20 30 10
PEACHTREE CITY 90 66 88 66 / 20 20 10 0
VIDALIA 91 68 91 69 / 20 10 5 0
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...11
LONG TERM....39
AVIATION...11
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
951 AM EDT MON SEP 9 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL DISSIPATE OVER OR NEAR THE AREA TODAY AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. THIS AREA OF HIGH PRESSURE WILL
THEN PREVAIL THROUGH THE MIDDLE OF THE WEEK BEFORE A BACKDOOR COLD
FRONT DROPS ACROSS THE AREA FRIDAY AND FRIDAY NIGHT. COOLER HIGH
PRESSURE WILL THEN BUILD INTO THE REGION FROM THE NORTH INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A VERY WEAK BACKDOOR FRONT MOVING SOUTH ACROSS NORTH CAROLINA WILL
DISSIPATE NORTH OF THE AREA TODAY. LIGHT WINDS WILL BECOME ONSHORE
THIS AFTERNOON AS HIGH PRESSURE BUILDS SOUTH AND A MODEST SEA
BREEZE CIRCULATION TAKES HOLD. A NUMBER OF THE HIGHER RESOLUTION
MODELS INCLUDING THE H3R...4KM NSSL WRF AND RAP ARE SPITTING OUT
ISOLATED SHOWERS/TSTMS ALONG THE SEA BREEZE FOR 1-2 HOURS THIS
AFTERNOON. NOT COMPLETELY CONVINCED ACTIVITY WILL FIRE AS IT
APPEARS THEY MAY BE OVER DEVELOPING THE CUMULUS FIELD ALONG THE
LEADING EDGE OF THE THERMALLY DIRECT CIRCULATION. PLAN TO KEEP THE
FORECAST DRY FOR NOW...ALTHOUGH SOME SMALL...SINGLE DIGIT GRIDDED
POPS WILL BE PLACED ALONG AND AHEAD OF THE SEA BREEZE FOR THE
AFTERNOON HOURS. SHOULD ANY SHOWERS/TSTMS DEVELOP...THEY WILL BE
SHORT LIVED GIVEN THE AMOUNT OF DRY AIR NOTED ALOFT. OVER THE
WATER...AN ISOLATED SHOWER WILL BE POSSIBLE THROUGH LATE THIS
MORNING ALONG A LINGERING LAND BREEZE CIRCULATION THAT IS NOTED
ABOUT 5 NM OFFSHORE.
A DECENT CUMULUS FIELD DEVELOP PRIOR TO NOON...BUT SHOULD CLEAR
OUT FROM EAST-WEST AS THE SEA BREEZE MOVES INLAND. HIGHS WILL FROM
THE LOWER 90S INLAND TO THE MID 80S AT THE BEACHES LOOK ON TRACK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE NORTH
WITH DRY CONDITIONS EXPECTED. JUST A REAL SMALL CHANCE OF A SHOWER
NEAR THE COAST LATE AS A WEAK COASTAL TROUGH ATTEMPTS TO DEVELOP.
OTHERWISE...LOWS SHOULD RANGE FROM THE UPPER 60S INLAND TO THE
MID 70S AROUND THE COAST.
TUESDAY THROUGH THURSDAY...EXPANSIVE UPPER LEVEL RIDGING WILL
PREVAIL OVER THE SOUTHEAST U.S. TUESDAY AND TUESDAY NIGHT...BUT
THEN AN INVERTED UPPER LEVEL TROUGH WILL RETROGRADE TOWARD THE
SOUTHEAST COAST WEDNESDAY AND WEDNESDAY NIGHT CAUSING THE EASTERN
PERIPHERY OF THE RIDGE TO ERODE. A LONGWAVE UPPER LEVEL TROUGH
WILL THEN BEGIN TO BECOME ESTABLISHED OVER THE EASTERN U.S. ON
THURSDAY. MEANWHILE AT THE SURFACE...HIGH PRESSURE WILL BUILD INTO
THE REGION FROM THE NORTH THROUGH WEDNESDAY...WITH THE AXIS OF THE
HIGH SHIFTING SOUTHWARD ACROSS THE AREA ON THURSDAY AS A COLD
FRONT APPROACHES FROM THE NORTHWEST.
STRONG SUBSIDENCE AND A LACK OF DEEP MOISTURE WILL GENERALLY KEEP
RAIN-FREE CONDITIONS IN PLACE. THE EXCEPTION COULD BE ALONG PARTS OF
THE IMMEDIATE SOUTHEAST GEORGIA COAST WHERE ISOLATED CONVECTION
COULD DEVELOP OFFSHORE IN AN AREA OF ENHANCED LOW LEVEL CONVERGENCE
AND SHIFT ONSHORE AT TIMES TUESDAY NIGHT THROUGH THURSDAY.
HIGH TEMPERATURES WILL GENERALLY BE AROUND 90...WITH COOLER
TEMPERATURES ALONG THE IMMEDIATE COAST. RADIATIONAL COOLING WILL BE
SUFFICIENT TO ALLOW TEMPERATURES TO FALL INTO THE UPPER 60S AWAY
FROM THE COAST...WITH A FEW MID 60S POSSIBLE IN WELL SHELTERED
AND/OR LOW LYING AREAS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH THE LONG TERM
PERIOD. A LONGWAVE UPPER LEVEL TROUGH WILL BE THE PREDOMINANT
FEATURE OVER THE EASTERN U.S. THROUGH SATURDAY...BEFORE THE TROUGH
LIFTS OUT AND THE FLOW BECOMES MORE ZONAL LATE IN THE WEEKEND INTO
EARLY NEXT WEEK. AT THE SURFACE...A BACKDOOR COLD FRONT WILL DROP
ACROSS THE AREA FRIDAY INTO FRIDAY NIGHT...THEN STALL OUT JUST SOUTH
OF THE AREA THROUGH THE REMAINDER OF THE LONG TERM PERIOD AS MUCH
COOLER HIGH PRESSURE BUILDS IN FROM THE NORTH.
THERE IS A CHANCE THAT SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE
PASSAGE OF THE COLD FRONT FRIDAY AND FRIDAY NIGHT...AND CONTINUE
INTO SATURDAY ACROSS MUCH OF THE AREA AS THE FRONT STALLS JUST TO
THE SOUTH. PRECIPITATION CHANCES WILL THEN CONTINUE INTO EARLY NEXT
WEEK ACROSS MUCH OF SOUTHEAST GEORGIA WHICH IS IN CLOSER PROXIMITY
TO THE FRONT AND THE DEEPER MOISTURE...WITH SOMEWHAT DRIER
CONDITIONS POSSIBLE FARTHER NORTH INTO PARTS OF SOUTHEAST SOUTH
CAROLINA.
TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH FRIDAY...THEN
COOLER/BELOW TEMPERATURES WILL OCCUR DURING THE REMAINDER OF THE
LONG TERM PERIOD AS A NORTHEAST FLOW DEVELOPS AS HIGH PRESSURE
BUILDS SOUTHWARD INTO THE REGION.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z TUE.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS WITH A GREATER
THAN 30 PERCENT CONFIDENCE AT THIS TIME.
&&
.MARINE...
TODAY AND TONIGHT...HIGH PRESSURE WILL BUILD IN FROM THE NORTH
CAUSING WINDS TO SHIFT TO EASTERLY BUT REMAINING 15 KT OR LESS.
WINDS COULD BACK TO MORE NORTHEAST NEAR THE COAST LATE TONIGHT AS
A WEAK COASTAL TROUGH OF LOW PRESSURE TRIES TO DEVELOP. SIGNIFICANT WAVE
HEIGHTS WILL BE UP TO 3 FT WITHIN 20 NM AND UP TO 4 FT BEYOND 20
NM...DOMINATED BY A 8-9 SECOND E/SE SWELL...AT LEAST THROUGH
TODAY.
TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL BUILD OVER THE
REGION FROM THE NORTH THROUGH WEDNESDAY...MAINTAINING AN ONSHORE
FLOW OVER THE WATERS WITH WIND SPEEDS GENERALLY 15 KT OR LESS. THE
FLOW WILL BECOME MORE SOUTHERLY ON THURSDAY AHEAD OF AN APPROACHING
COLD FRONT...WHICH IS EXPECTED TO DROP ACROSS THE WATERS FRIDAY AND
FRIDAY NIGHT SHIFTING THE WINDS NORTHEAST IN ITS WAKE. A STRONG
NORTHEAST SURGE WILL THEN OCCUR FRIDAY NIGHT AND SATURDAY...LIKELY
RESULTING IN SMALL CRAFT ADVISORY CONDITIONS OVER PORTIONS OF THE
WATERS. SEAS WILL GENERALLY BE NO HIGHER THAN 2-4 FT...GREATEST OVER
THE OUTER GEORGIA WATERS...THROUGH FRIDAY BEFORE INCREASING A COUPLE
OF FEET SATURDAY AS THE STRONG NORTHEAST FLOW DEVELOPS AND THE FETCH
INCREASES.
WATERSPOUTS...VISIBLE SATELLITE AND SURFACE OBSERVATIONS SHOW
TOWERING CUMULUS BEGINNING TO DEVELOP ALONG A WELL-DEFINED LAND
BREEZE NOTED ABOUT 5 NAM OFFSHORE. WIND PROFILES SUPPORT A RISK
FOR WATERSPOUTS THROUGH ABOUT NOON. A MARINE WEATHER STATEMENT
WILL BE ISSUED TO HIGHLIGHT THIS RISK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
945 AM EDT MON SEP 9 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL DISSIPATE OVER OR NEAR THE AREA TODAY AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. THIS AREA OF HIGH PRESSURE WILL
THEN PREVAIL THROUGH THE MIDDLE OF THE WEEK BEFORE A BACKDOOR COLD
FRONT DROPS ACROSS THE AREA FRIDAY AND FRIDAY NIGHT. COOLER HIGH
PRESSURE WILL THEN BUILD INTO THE REGION FROM THE NORTH INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A VERY WEAK BACKDOOR FRONT MOVING SOUTH ACROSS NORTH CAROLINA WILL
DISSIPATE NORTH OF THE AREA TODAY. LIGHT WINDS WILL BECOME ONSHORE
THIS AFTERNOON AS HIGH PRESSURE BUILDS SOUTH AND A MODEST SEA
BREEZE CIRCULATION TAKES HOLD. A NUMBER OF THE HIGHER RESOLUTION
MODELS INCLUDING THE H3R...4KM NSSL WRF AND RAP ARE SPITTING OUT
ISOLATED SHOWERS/TSTMS ALONG THE SEA BREEZE FOR 1-2 HOURS THIS
AFTERNOON. NOT COMPLETELY CONVINCED ACTIVITY WILL FIRE AS IT
APPEARS THEY MAY BE OVER DEVELOPING THE CUMULUS FIELD ALONG THE
LEADING EDGE OF THE THERMALLY DIRECT CIRCULATION. PLAN TO KEEP THE
FORECAST DRY FOR NOW...ALTHOUGH SOME SMALL...SINGLE DIGIT GRIDDED
POPS WILL BE PLACED ALONG AND AHEAD OF THE SEA BREEZE FOR THE
AFTERNOON HOURS. SHOULD ANY SHOWERS/TSTMS DEVELOP...THEY WILL BE
SHORT LIVED GIVEN THE AMOUNT OF DRY AIR NOTED ALOFT. OVER THE
WATER...AN ISOLATED SHOWER WILL BE POSSIBLE THROUGH LATE THIS
MORNING ALONG A LINGERING LAND BREEZE CIRCULATION THAT IS NOTED
ABOUT 5 NM OFFSHORE.
A DECENT CUMULUS FIELD DEVELOP PRIOR TO NOON...BUT SHOULD CLEAR
OUT FROM EAST-WEST AS THE SEA BREEZE MOVES INLAND. HIGHS WILL FROM
THE LOWER 90S INLAND TO THE MID 80S AT THE BEACHES LOOK ON TRACK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE NORTH
WITH DRY CONDITIONS EXPECTED. JUST A REAL SMALL CHANCE OF A SHOWER
NEAR THE COAST LATE AS A WEAK COASTAL TROUGH ATTEMPTS TO DEVELOP.
OTHERWISE...LOWS SHOULD RANGE FROM THE UPPER 60S INLAND TO THE
MID 70S AROUND THE COAST.
TUESDAY THROUGH THURSDAY...EXPANSIVE UPPER LEVEL RIDGING WILL
PREVAIL OVER THE SOUTHEAST U.S. TUESDAY AND TUESDAY NIGHT...BUT
THEN AN INVERTED UPPER LEVEL TROUGH WILL RETROGRADE TOWARD THE
SOUTHEAST COAST WEDNESDAY AND WEDNESDAY NIGHT CAUSING THE EASTERN
PERIPHERY OF THE RIDGE TO ERODE. A LONGWAVE UPPER LEVEL TROUGH
WILL THEN BEGIN TO BECOME ESTABLISHED OVER THE EASTERN U.S. ON
THURSDAY. MEANWHILE AT THE SURFACE...HIGH PRESSURE WILL BUILD INTO
THE REGION FROM THE NORTH THROUGH WEDNESDAY...WITH THE AXIS OF THE
HIGH SHIFTING SOUTHWARD ACROSS THE AREA ON THURSDAY AS A COLD
FRONT APPROACHES FROM THE NORTHWEST.
STRONG SUBSIDENCE AND A LACK OF DEEP MOISTURE WILL GENERALLY KEEP
RAIN-FREE CONDITIONS IN PLACE. THE EXCEPTION COULD BE ALONG PARTS OF
THE IMMEDIATE SOUTHEAST GEORGIA COAST WHERE ISOLATED CONVECTION
COULD DEVELOP OFFSHORE IN AN AREA OF ENHANCED LOW LEVEL CONVERGENCE
AND SHIFT ONSHORE AT TIMES TUESDAY NIGHT THROUGH THURSDAY.
HIGH TEMPERATURES WILL GENERALLY BE AROUND 90...WITH COOLER
TEMPERATURES ALONG THE IMMEDIATE COAST. RADIATIONAL COOLING WILL BE
SUFFICIENT TO ALLOW TEMPERATURES TO FALL INTO THE UPPER 60S AWAY
FROM THE COAST...WITH A FEW MID 60S POSSIBLE IN WELL SHELTERED
AND/OR LOW LYING AREAS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT THROUGH THE LONG TERM
PERIOD. A LONGWAVE UPPER LEVEL TROUGH WILL BE THE PREDOMINANT
FEATURE OVER THE EASTERN U.S. THROUGH SATURDAY...BEFORE THE TROUGH
LIFTS OUT AND THE FLOW BECOMES MORE ZONAL LATE IN THE WEEKEND INTO
EARLY NEXT WEEK. AT THE SURFACE...A BACKDOOR COLD FRONT WILL DROP
ACROSS THE AREA FRIDAY INTO FRIDAY NIGHT...THEN STALL OUT JUST SOUTH
OF THE AREA THROUGH THE REMAINDER OF THE LONG TERM PERIOD AS MUCH
COOLER HIGH PRESSURE BUILDS IN FROM THE NORTH.
THERE IS A CHANCE THAT SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THE
PASSAGE OF THE COLD FRONT FRIDAY AND FRIDAY NIGHT...AND CONTINUE
INTO SATURDAY ACROSS MUCH OF THE AREA AS THE FRONT STALLS JUST TO
THE SOUTH. PRECIPITATION CHANCES WILL THEN CONTINUE INTO EARLY NEXT
WEEK ACROSS MUCH OF SOUTHEAST GEORGIA WHICH IS IN CLOSER PROXIMITY
TO THE FRONT AND THE DEEPER MOISTURE...WITH SOMEWHAT DRIER
CONDITIONS POSSIBLE FARTHER NORTH INTO PARTS OF SOUTHEAST SOUTH
CAROLINA.
TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH FRIDAY...THEN
COOLER/BELOW TEMPERATURES WILL OCCUR DURING THE REMAINDER OF THE
LONG TERM PERIOD AS A NORTHEAST FLOW DEVELOPS AS HIGH PRESSURE
BUILDS SOUTHWARD INTO THE REGION.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z TUE.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS WITH A GREATER
THAN 30 PERCENT CONFIDENCE AT THIS TIME.
&&
.MARINE...
TODAY AND TONIGHT...HIGH PRESSURE WILL BUILD IN FROM THE NORTH
CAUSING WINDS TO SHIFT TO EASTERLY BUT REMAINING 15 KT OR LESS.
WINDS COULD BACK TO MORE NORTHEAST NEAR THE COAST LATE TONIGHT AS
A WEAK COASTAL TROUGH OF LOW PRESSURE TRIES TO DEVELOP. SIGNIFICANT WAVE
HEIGHTS WILL BE UP TO 3 FT WITHIN 20 NM AND UP TO 4 FT BEYOND 20
NM...DOMINATED BY A 8-9 SECOND E/SE SWELL...AT LEAST THROUGH
TODAY.
TUESDAY THROUGH SATURDAY...HIGH PRESSURE WILL BUILD OVER THE
REGION FROM THE NORTH THROUGH WEDNESDAY...MAINTAINING AN ONSHORE
FLOW OVER THE WATERS WITH WIND SPEEDS GENERALLY 15 KT OR LESS. THE
FLOW WILL BECOME MORE SOUTHERLY ON THURSDAY AHEAD OF AN APPROACHING
COLD FRONT...WHICH IS EXPECTED TO DROP ACROSS THE WATERS FRIDAY AND
FRIDAY NIGHT SHIFTING THE WINDS NORTHEAST IN ITS WAKE. A STRONG
NORTHEAST SURGE WILL THEN OCCUR FRIDAY NIGHT AND SATURDAY...LIKELY
RESULTING IN SMALL CRAFT ADVISORY CONDITIONS OVER PORTIONS OF THE
WATERS. SEAS WILL GENERALLY BE NO HIGHER THAN 2-4 FT...GREATEST OVER
THE OUTER GEORGIA WATERS...THROUGH FRIDAY BEFORE INCREASING A COUPLE
OF FEET SATURDAY AS THE STRONG NORTHEAST FLOW DEVELOPS AND THE FETCH
INCREASES.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
205 AM CDT MON SEP 9 2013
.DISCUSSION...
251 PM CDT
MAIN FORECAST CONCERNS WILL BE TEMPERATURES MONDAY AND TUESDAY AS
HEAT RETURNS TO THE AREA...AS WELL AS PERIODIC CHANCES FOR
THUNDERSTORMS TONIGHT THROUGH EARLY MONDAY...AND AGAIN TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT.
THIS AFTERNOON...A COLD FRONT STRETCHES FROM SOUTH DAKOTA SOUTHEAST
INTO SOUTHERN ILLINOIS. DEW POINTS POOLING INTO THE LOW 70S ALONG THE
FRONTAL BOUNDARY HAVE LED TO MLCAPE AXIS OF 2000-2500 J/KG JUST
SOUTH OF THE CWA...WITH JUST OVER 1000 J/KG INTO THE FAR SOUTHERN
CWA PER SPC MESOANALYSIS. WEAK SURFACE CONVERGENCE ACROSS CENTRAL
ILLINOIS...WEAKLY ENHANCED BY DIFFERENTIAL HEATING BETWEEN THE
THICKER CIRRUS SHIELD TO OUR SOUTH HAS LED TO A FEW SHOWERS AND
THUNDERSTORMS ACROSS THE SOUTHERN CWA. OVER THE NEXT FEW
HOURS...EXPECT THE WIDELY SCATTERED ACTIVITY TO CONTINUE...BUT
SHOULD FADE WITH LOSS OF HEATING THIS EVENING...PROVIDING AT LEAST A
BRIEF DRY WINDOW ACROSS THE CWA.
TONIGHT THROUGH TOMORROW...
CLOSED UPPER LOW CURRENTLY OVER MONTANA IS PROGGED TO MOVE EAST THIS
EVENING AND TONIGHT...WHILE SURFACE LOW OVER THE PLAINS LIFTS
NORTHEAST...DEEPENING SLIGHTLY AS IT MOVES OVER MINNESOTA BY
TOMORROW AFTERNOON. THE FRONTAL BOUNDARY TO OUR SOUTH WILL BEGIN TO
LIFT NORTH ACROSS THE AREA TONIGHT WITH A BAND OF MID LEVEL
ISENTROPIC ASCENT SLOWLY TRANSITIONING WEST TO EAST ACROSS THE
CWA FROM LATE THIS EVENING THROUGH MONDAY MORNING...BRINGING AT
LEAST A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS THROUGH THE
OVERNIGHT HOURS. NAM SUGGESTS A SLOWER PROGRESSION OF THIS FEATURE
WITH ASCENT STILL OCCURRING IN THE EASTERN PORTIONS OF THE CWA EARLY
MONDAY AFTERNOON...AT WHICH TIME MODERATE INSTABILITY WILL HAVE
DEVELOPED...WEAKLY CAPPED ON THE LEADING EDGE OF THE EML WHICH WILL
BE ADVECTING EAST INTO THE AREA THROUGH THE DAY. IF THIS PANS
OUT...CONCERNED THAT WE MAY SEE SOME INTENSIFICATION OF ANY SHOWERS
THAT MAY DEVELOP OVERNIGHT AS THEY BECOME ROOTED IN THE BOUNDARY
LAYER LATE TOMORROW MORNING OR EARLY AFTERNOON OVER FAR EAST CENTRAL
ILLINOIS OR NORTHWEST INDIANA. OVERALL CONFIDENCE IN PRECIP IS PRETTY
LOW THOUGH...WITH LACK OF ANY SIGNIFICANT UPPER LEVEL SUPPORT
THROUGH THE PERIOD. IF ANYTHING DID DEVELOP COVERAGE MAY END OF
STAYING PRETTY LOW.
ATTENTION TURNS TO TEMPERATURES TOMORROW AFTERNOON. STOUT CAPPING
INVERSION ADVECTS IN FROM THE WEST AND MODEST DRYING SHOULD ALLOW
SKIES TO CLEAR BEHIND ANY MID LEVEL CLOUDINESS ASSOCIATED WITH THE
WARM FRONT EARLY IN THE DAY. BETWEEN 18Z AND 00Z...H92 TEMPS ARE
EXPECTED TO WARM FROM AROUND 23C TO NEAR 27C...MOVING OFF THE CHARTS
SO TO SPEAK WITH RESPECT TO LOCAL UPPER AIR CLIMATOLOGY. QUITE A BIT
OF VARIANCE IN MODEL PROG SURFACE TEMPERATURES TOMORROW. GFS AND GEM
SHOW LOW TO MID 80S ACROSS THE CWA...WHILE THE NAM AND ECMWF
INDICATE TEMPERATURES SOARING INTO 90S. GIVEN THE EXPECTED WARM
ADVECTION AND CLEARING SKIES...SEE LITTLE SUPPORT FOR THE COOLER
MODELS...AND ENDED UP BUMPING TEMPERATURES A COUPLE DEGREES MONDAY
TOWARDS A BLEND OF THE ECMWF/ECMWFBC...CALLING FOR LOW 90S ACROSS
THE CWA...AND 91/93 AT ORD/RFD RESPECTIVELY.
TUESDAY...
CONTINUE TO LOOK AT NEAR RECORD HIGH TEMPERATURES ON TUESDAY AS WE
SIT SQUARELY UNDER THE THERMAL RIDGE. MODELS IN DECENT AGREEMENT
SHOWING H85 TEMPS BETWEEN 21-22C...AND H92 TEMPS BETWEEN 27-28C...
AGAIN OFF THE CHARTS WITH RESPECT TO LOCAL CLIMATOLOGY. DEEP MIXING
DURING THE DAY SHOULD HELP TO MIX THE DEW POINTS TOWARDS THE UPPER
50S...WHICH WILL HELP TEMPERATURES QUICKLY RESPOND. WITH GREATER
CONFIDENCE THAT WE SHOULD SEE PLENTY OF SUNSHINE...FULLY EXPECT TO
BE FLIRTING WITH IF NOT EXCEEDING RECORD HIGHS ON TUESDAY. SEE
CLIMATE SECTION FOR INFORMATION ON RECORD TEMPS. BLENDED WITH
ECMWF/GEMNH GUIDANCE WHICH TENDS TO VERIFY WELL UNDER A STRONG
THERMAL RIDGE...BUMPING UP TEMPS ABOUT A DEGREE OR SO FROM THE
PREVIOUS FORECAST...AND CALLING FOR TEMPS INTO THE MID 90S ACROSS
THE CWA.
WEDNESDAY...
A COLD FRONT IS EXPECTED TO SAG SOUTH ACROSS THE CWA ON WEDNESDAY.
EXPECT A SPREAD IN HIGH TEMPERATURES NORTH TO SOUTH ACROSS THE CWA
DEPENDING ON FRONTAL TIMING...WITH LOW 80S IN THE NORTH TO LOW 90S
IN THE SOUTH. MODERATE INSTABILITY IS EXPECTED TO DEVELOP JUST AHEAD
OF THE FRONT...WITH THUNDERSTORMS EXPECTED PARTICULARLY DURING THE
AFTERNOON HOURS AIDED BY SURFACE HEATING. OVERALL DYNAMICS WITH THIS
SYSTEM APPEAR PRETTY WEAK...WITH WEAK CONVERGENCE ALONG THE
FRONT...AND THE MAIN UPPER WAVE EXPECTED TO PASS WELL TO THE NORTH.
THIS SHOULD LEAD TO LOWER COVERAGE OF THUNDERSTORMS ALONG THE FRONT.
THURSDAY THROUGH SUNDAY...
STRONG CANADIAN HIGH WILL BUILD SOUTH ACROSS THE AREA PROVIDING A
DRIER PERIOD AS WELL AS COOLER WEATHER. BOTH THE GFS AND ECMWF
ADVERTISE H85 TEMPS FALLING TO AROUND 3C FRIDAY AFTERNOON.
FRIDAY...WHICH SHOULD BE THE COOLEST DAY THE UPCOMING WEEK...WE ARE
LOOKING AT HIGHS ONLY THE THE UPPER 60S NORTH OF I-80...AND AROUND
70 SOUTH. TEMPERATURES SHOULD START TO MODERATE NEXT WEEKEND AS THE
HIGH SHIFTS EAST AND RETURN FLOW SPREADS OVER THE AREA.
DEUBELBEISS
&&
.CLIMATE...
THERE IS A CHANCE THAT RECORD WARM LOWS WILL OCCUR TUESDAY
SEPTEMBER 10TH...AND ALSO SLIGHT CHANCE OF RECORD HIGH TEMPERATURES.
CHICAGO:
RECORD HIGH: 95 (1983)
RECORD WARM LOW: 75 (1912)
ROCKFORD:
RECORD HIGH: 96 (1931)
RECORD WARM LOW: 70 (2000)
TRS/RC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* VEERING AND INCREASING WINDS AFTER SUNRISE.
* SLIGHT CHANCE OF MVFR CEILINGS DURING REST OF OVERNIGHT INTO
EARLY MORNING.
TRS
//DISCUSSION...UPDATED 06Z...
A LARGE HIGH CENTERED WELL EAST OF THE REGION WILL CONTINUE TO
SLOWLY MOVE SOUTHEASTWARD TO THE NORTHEASTERN AND NEW ENGLAND
STATES BY DAYBREAK. MEANWHILE...LOW PRESSURE CONTINUED TO DEVELOP
IN THE NORTHERN HIGH PLAINS AS AN UPPER LOW MOVED OVER SOUTHERN
CANADIAN AND THE NORTHERN ROCKIES. THE UPPER LOW IS PROGGED TO
BEGIN TO TRANSITION INTO AN OPEN WAVE AS IT PROGRESSES TO FAR
SOUTHEASTERN SASKATCHEWAN...FAR SOUTHERN MANITOBA AND THE FAR
NORTHERN PLAINS DURING THE DAY. S A RESULT THE ASSOCIATED SURFACE
LOW ALSO PROGRESSES EASTWARD AND TO ND BY THIS EVENING...BUT ONLY
SLIGHTLY DEEPENING DUE TO THE PARENT UPPER WAVE DE-AMPLIFYING.
BETWEEN THE EASTERN HIGH AND THE NORTHERN PLAINS LOW THE LOW LEVEL
FLOW WILL GRADUALLY VEER FROM SOUTHEASTERLY TO SOUTH-SOUTHWESTERLY
WHILE BECOMING SOMEWHAT GUSTY BY MIDDAY AS THE MIXED LAYER DEEPENS
ENOUGH TO TAP INTO THE INCREASING SOUTHWEST FLOW BETWEEN 1000 AND
2000 FT AGL PROGGED AT AN AVERAGE OF AROUND 22KT BY 10.00Z.
ANALYSIS OF 09.00Z RAOB DATA SHOWED SIGNIFICANT 700 HPA WARM AIR
ADVECTION REACHING ACROSS SOUTHERN WI AND NORTHERN IL...WITH THE
850 HPA ANALYSIS SHOWING STRONG WARM AIR ADVECTION ACROSS IA AND
NORTHERN MO. EXAMINATION OF LOWER AND MID LEVEL ISENTROPIC SURFACE
HEIGHTS...PRESSURE ADVECTION...AND SATURATION DEFICIT 6 HOUR PROGS
OF THE 09.00Z NAM80 VERIFIED QUITE WELL BASED ON SATELLITE
PICTURES AND METARS AS TO WHERE STRATOCUMULUS AND ALTO-CUMULUS
WOULD BE LOCATED. BASED ON THE VERY GOOD SHORT TERM PERFORMANCE
HAVE USED THE ABOVE MENTIONED PARAMETERS OF THE 00Z NAM80 MODEL
RUN TO PROJECT WHERE LOWER AND MID LEVEL CLOUDS WILL BE LOCATED
LATER TODAY.
RECENT SATELLITE PICTURES AND METARS PUT THE SOUTHWESTERN EDGE OF
THE STRATOCU ROM FAR SOUTHWEST WI ACROSS FAR NORTH CENTRAL AND
FAR NORTHEAST IL TO NORTHWEST IN...WITH THE BACK EDGE OF THE MID
LEVEL CLOUD DECK FURTHER TO THE NORTHWEST THROUGH NORTH-NORTHEAST
OF THE LOCAL AREA. THE NOSE OF THE MID AND LOWER LEVEL WARM AIR
ADVECTION IS PROGGED TO CONTINUE TO PUSH TO THE EAST-NORTHEAST
INTO THE GREAT LAKES WITH TIME TODAY AND EXPECT THE BACK EDGE OF
THE STRATOCU DECK TO DO THE SAME AND FOR THE MOST PART CLEAR OF
THE TERMINALS BY MID MORNING.
THE VEERING LOW LEVEL FLOW HAS BEEN SLOWLY ADVECTING IN SLIGHTLY
HIGHER DEW POINTS DURING THE LATE NIGHT SO EXPECT SOME VERY LIGHT
FOG AND/OR HAZE DURING THE PREDAWN THROUGH EARLY MORNING HOURS.
DEW POINTS LOCALLY ARE PROGGED TO CONTINUE TO SLOWLY CLIMB INTO
THE UPPER 60S AND LOWER 70S BY MIDDAY AS THE LOW LEVEL FLOW
CONTINUES TO VEER FROM SOUTHEASTERLY O OUT OF THE SOUTH. GENERALLY
CLEAR SKY DURING THE MID AND LATE MORNING WILL ALLOW GOOD SURFACE
HEATING WARMING THE SURFACE TO PROGGED CONVECTIVE TEMPERATURES IN
THE MID 80S BY EARLY AFTERNOON SO EXPECT SCATTERED CUMULUS
DEVELOPMENT BUT COVERAGE WILL BE LIMITED AS ADDITIONAL HEATING AND
DEEPENING OF THE MIXED LAYER DROPS DEW POINTS A BIT AS THE
AFTERNOON PROGRESSES.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE THAT VISIBILITIES PRE-DAWN AND EARLY A.M. WILL
REMAIN VFR...HIGH CONFIDENCE NO LOWER THAN HIGH END MVFR.
* MEDIUM CONFIDENCE IN FORECAST AVERAGE VELOCITY OF GUSTS LATER
MORNING THROUGH AFTERNOON +/- 3KT.
* HIGH CONFIDENCE ALL OTHER FORECAST TRENDS.
TRS
//OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z...
TUESDAY...VFR. CHANCE OF TSRA WITH MVFR POSSIBLE TUES NGT.
WEDNESDAY...CHANCE TSRA. MVFR POSSIBLE.
THURSDAY THROUGH SATURDAY...VFR.
RATZER
&&
.MARINE...
139 PM CDT
THE WINDS ACROSS THE LAKE HAVE VEERED EASTWARD IN RESPONSE TO THE
SURFACE HIGH BUILDING EASTWARD ACROSS FAR SOUTHERN ONTARIO AND THE
UPPER GREAT LAKES. THIS SURFACE HIGH WILL CONTINUE
EAST-SOUTHEASTWARD ACROSS THE NORTHERN ATLANTIC COAST BY EARLY
MONDAY. THIS WILL ALLOW THE WINDS TO CONTINUE VEERING TO THE
SOUTHEAST TONIGHT...AND THEN SOUTHERLY FOR MONDAY. WIND SPEEDS WILL
LIKELY REMAIN ELEVATED UP TO 15 TO 25 KT INTO MONDAY. HOWEVER...IT
APPEARS THAT SOME 30 KT SOUTHERLY WINDS WILL DEVELOP LATE MONDAY
AND MONDAY NIGHT...ESPECIALLY OVER THE NORTHERN HALF OF THE LAKE AS
A POTENT AREA OF LOW PRESSURE TRACKS ACROSS LAKE SUPERIOR.
THIS LOW LOOKS TO DROP A WEAK COLD FRONT ACROSS THE LAKE BY TUESDAY
NIGHT. HOWEVER...THE WIND SPEEDS LOOK TO ABATE DURING THIS TIME. A
SECOND AREA OF LOW PRESSURE IS FORECAST TO SHIFT ACROSS ONTARIO
AROUND MID WEEK...AND THIS LOW LOOKS TO DROP A MUCH STRONGER COLD
FRONT DOWN THE LAKE INTO THURSDAY. A PERIOD OF STRONG NORTHERLY
WINDS IS POSSIBLE BEHIND THIS FRONT LATER IN THE WEEK AS A MUCH
COLDER AIR MASS SPILLS OVER THE LAKE AHEAD OF A POTENT SURFACE HIGH.
FOR THE NEAR SHORE WATERS...I PLAN ON KEEPING THE SMALL CRAFT
ADVISORY AS IS THROUGH THIS EVENING FOR 4 TO 7 FOOT WAVES ALONG THE
ILLINOIS NEAR SHORES. THE WAVES WILL LIKELY BE SLOW TO SUBSIDE
TONIGHT ALONG THE NORTHERN ILLINOIS NEAR SHORES...BUT IT APPEARS
THAT THEY WILL SUBSIDE INTO THE 2 TO 5 FOOT RANGE...THUS AN
EXTENSION TO THE SMALL CRAFT ADVISORY IS NOT ANTICIPATED AT THIS
TIME.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
Area Forecast Discussion
National Weather Service Lincoln IL
1105 PM CDT Sun Sep 8 2013
.DISCUSSION...
ISSUED 842 PM CDT Sun Sep 8 2013
Latest surface analysis indicates the "cool" front that pushed
through our area early this morning has started back north as a
warm front this evening. Most winds, except for our far north and
east, have turned more into a southeast to south direction
suggesting the boundary is lifting thru our forecast area. Question
now is precip chances with the boundary already shifting into our
northern areas this evening. 00z 850 mb map indicates the warm front
situated from from eastern Iowa thru extreme west central IL. Some
weak speed convergence noted over northeast Mo and west central IL
early this evening but the stronger core of winds was well to our
west. Last several runs of the HRRR model showing some showers trying
to develop over extreme southwest IL after midnight and then tracking
south. Evening 700 mb map indicating another surge of very warm
air...+12C just to our west, which should advect into our area on
Monday as upper level heights build over the region with some very
hot temperatures for the first half of the work week.
Overall, zone forecast is in good shape. Only making some minor
adjustments to the overnight hours, specifically for temperatures
and cloud cover, along with some overnight adjustments to wording
in the ZFP. Should have the update out by 900 pm.
&&
.AVIATION...
ISSUED 1105 PM CDT Sun Sep 8 2013
Other than the threat for some MVFR vsbys in fog from 09z-13z, we
are still expecting VFR conditions for the remainder of the period.
Warm frontal boundary edging slowly north across the forecast area
tonight and will be north of our area by Monday morning. Abudant
low level moisture and lack of cloud cover, along with a light wind
regime should lead to at least some patchy fog just before dawn. What
fog we do see during the early morning hours should quickly dissipate
by 14z as south to southwest winds increase to 10 to 15 kts with a
few gusts possible during the afternoon, and then diminish to around
10 kts by 00z. Forecast soundings indicate some cumulus clouds will
form by early afternoon, mainly east of I-55, affecting DEC and CMI
with cloud bases of 4500-5000 feet, which should dissipate by 23z.
Smith
&&
.PREV DISCUSSION...
ISSUED 250 PM CDT Sun Sep 8 2013
SHORT TERM...Today through Thursday
A frontal boundary over central IN/IL to near the IA/MO border
will linger isolated showers and thunderstorms into this evening.
MCS that brought heavy rains to westcentral IL overnight/early
this morning has dissipate as it moved sse into southern IL by
afternoon. Not much lift or convergence along frontal boundary but
heating of tropical airmass with dewpoints in the upper 60s to
near 70F giving unstable capes peaking from 1.5-3K j/kg late this
afternoon. Some stratus and fog more likely over northern IL
tonight as front lifts northward toward northern IL overnight.
Areas from I-74 north may see some of this stratus and fog but
more likely further north. Lows overnight close to dewpoints in
the upper 60s, to near 70F sw areas.
Hot conditions still on tap for Monday and Tuesday with highs in
the low to mid 90s Monday and into the 90s Tuesday with some upper
90s sw areas. Will likely be shy of record highs near 100F on
Monday but may be close to record highs on Tuesday which are 97F
at Peoria and Lincoln and 98F in Springfield. Kept dry conditions
from Monday through Tuesday as 592 dm 500 mb subtropical ridge
over the central plains shifts ese into the mid ms and tn valleys.
Models continue to drive a cold front se toward nw IL late
Wednesday and brings a chance of showers and thunderstorms mainly
to the IL river valley. Cold front to push se through central and
se IL Wed night and bring a chance of showers and thunderstorms
with isolated convection lingering over se IL thursday. Still
quite warm and humid Wed with highs in the lower 90s, with some
upper 80s nw of the IL river where more clouds arrive during the
day Wed. Highs Thu mostly in the mid 80s.
LONG TERM...Thursday night through Sunday
A quiet and cooler/less humid pattern expected during this time
with highs in the mid to upper 70s Fri into this weekend and lows
in the low to mid 50s. Large Canadian high pressure of 1027 mb
settles se into the Great Lakes region by Saturday morning and to
control IL`s weather for a few days. GFS and ECMWF models show a
disturbance moving ne toward central IL later in the weekend but
will keep a dry forecast since models first time showing this.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
353 PM CDT MON SEP 9 2013
.SHORT TERM.../TONIGHT /...
ISSUED AT 324 PM CDT MON SEP 9 2013
MAIN FORECAST CONCERN IS WITH WEAK FRONT EXPECTED TO DIP INTO FAR
NORTHERN IOWA OVERNIGHT TONIGHT. LATEST HOPWRF SUGGEST SOME WEAK
ISOLATED DEVELOPMENT ALONG THE FRONT PAST 05Z TUESDAY IN SOUTHERN
MINNESOTA AND NORTHWEST IOWA. THE HRRR AND 4.0 SPC WRF SUGGEST
SIMILAR TREND...ALTHOUGH SLIGHTLY FURTHER NORTHWEST. THERE IS SOME
WEAK FRONTOGENETICAL FORCING BETWEEN 850MB AND 700MB LATER TONIGHT
INTO EARLY TUESDAY MORNING THAT SNEAKS INTO NORTHWEST IOWA. SO
KEPT SLIGHT POPS GOING ACROSS THE NORTH TONIGHT...BUT HAVE LOW
CONFIDENCE WITH ANY SIGNIFICANT RAINFALL SINCE SHOWERS WILL BE
VERY HIGH BASED. WENT CLOSER TO THE ECMWF FOR LOW TEMPS TONIGHT
WITH THE WAA CONTINUING AHEAD OF THE FRONT.
.LONG TERM.../TUESDAY THROUGH MONDAY/...
ISSUED AT 324 PM CDT MON SEP 9 2013
MAIN FORECAST CONCERNS FOR TUESDAY INT WEDNESDAY REVOLVE AROUND A
COLD FRONTAL PASSAGE. MOST OF THE FORCING WITH THE FRONT SHIFTS
NORTH AND EAST OF THE AREA. WHILE DEEP SHEAR IS UNIMPRESSIVE THERE
IS SOME LOW LEVEL SHEAR COINCIDENT WITH THE FRONT. MODELS CONTINUE
TO SHOW LITTLE IN THE WAY OF RAINFALL AND THAT BEING POST FRONTAL.
THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME LATE
AFTERNOON AND EVENING WHEN A SHORT WAVE MOVES ACROSS MAINLY THE
NORTHERN FORECAST AREA AND INTERACTS WITH THE FRONT. SOUNDINGS
SHOW STEEP LAPSE RATES SO WHILE ANY STORMS WOULD BE ISOLATED TO
SCATTERED AT BEST THERE IS SOME POTENTIAL FOR AN ISOLATED WIND
THREAT. THE HEAT WILL STILL BE ON FOR SOUTHEAST PORTIONS OF THE
STATE TOMORROW AND THERE IS SOME CONCERN THAT WITH TWO WARM NIGHTS
NOW AND WHAT WILL BE THE SECOND HOT DAY THERE COULD BE SOME
CUMULATIVE EFFECTS OF PROLONGED HEAT. HOWEVER WITH LONGER NIGHTS
THERE SHOULD BE MORE TIME FOR THE BODY TO RECOVER SO WE WILL
CONTINUE TO HANDLE THE HEAT WITH A SPECIAL WEATHER STATEMENT.
THE FRONT GRADUALLY SHIFTS TO THE SOUTH THROUGH WEDNESDAY FOLLOWED
BY COOLER TEMPS FOR THE REST OF THE WEEK.
FOR THE WEEKEND THE MODELS SUGGEST A SHORTWAVE PUSHING ACROSS THE
NORTHERN PLAINS AGAIN AND POSSIBLY INTO THE UPPER MIDWEST. TIMING
AND STRENGTH OF THE SHORTWAVE ARE STILL IN QUESTION BUT THERE
APPEAR TO BE AT LEAST CHANCES FOR THUNDERSTORMS AND GRIDS CONTINUE
TO REFLECT THESE CHANCES.
&&
.AVIATION...09/18Z
ISSUED AT 1230 PM CDT MON SEP 9 2013
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE FORECAST PERIOD. MIXING
WILL CONTINUE TO INCREASE THIS AFTERNOON BEFORE WINDS DECOUPLE
BETWEEN 00-01Z TONIGHT. NOT ANTICIPATING ANY FOG TONIGHT AS WINDS
WILL REMAIN STRONG ENOUGH. MIXING LOOKS TO INCREASE AGAIN LATE
TOMORROW MORNING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...FAB/PODRAZIK
LONG TERM...FAB
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS GOODLAND KS
237 PM MDT MON SEP 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 237 PM MDT MON SEP 9 2013
AS OF 3 PM CDT...2 PM MDT...SKIES ACROSS THE TRI-STATE AREA WERE
MOSTLY CLEAR WITH THE EXCEPTION OF SOME PATCHES OF DAYTIME CUMULUS.
TEMPERATURES HAVE RISEN INTO THE LOW 90S TO NEAR 100 IN A FEW SPOTS
ACROSS RED WILLOW...DECATUR...NORTON AND GRAHAM COUNTIES. WINDS WERE
GENERALLY FROM THE SOUTH AT 10 TO 20 MPH WITH GUSTS 25 TO 30 MPH.
DEWPOINTS WERE ON A SLOW DECLINE THIS AFTERNOON. A COLD FRONT WAS
LOCATED ACROSS NORTHEAST COLORADO AND SOUTHWEST NEBRASKA. AN AREA OF
LOW PRESSURE WAS DRAPED ACROSS THE AREA...STRETCHING FROM SOUTHWEST
NEBRASKA TO THE COLORADO FRONT RANGE. FIRE WEATHER HAS BECOME A
CONCERN THIS AFTERNOON AND WILL BE ADDRESSED IN A FIRE WEATHER
SECTION BELOW.
FOR THIS AFTERNOON AND TONIGHT...SURFACE CONVERGENCE IS PROJECTED TO
INCREASE ALONG THE COLD FRONT...ALLOWING SOME ISOLATED TO WIDELY
SCATTERED THUNDERSTORMS TO DEVELOP. IN ADDITION...CONVECTION
DEVELOPING OVER THE ROCKIES MAY ORGANIZE AND MOVE EAST INTO THE
REGION FROM THE LATEST RUNS OF THE HRRR MODEL. MOST OTHER MODELS
HOLD ALL PRECIPITATION OFF AND KEEP IT TO THE NORTHWEST OF THE
FORECAST AREA. A STRONG STORM OR TWO IS POSSIBLE WITH DAMAGING
WINDS AND SMALL HAIL AS THE MAIN THREAT. HOWEVER...INSTABILITY IS
NOT AS HIGH AS NEEDED FOR A MORE WIDESPREAD THREAT OF SEVERE
WEATHER. THE FRONT SHOULD MOVE TO THE SOUTH DURING THE OVERNIGHT
HOURS...BRINGING COOLER TEMPERATURES...MORE MOISTURE TO THE AIR
AND A WIND SHIFT. LOW TEMPERATURES WILL VARY ACROSS THE REGION
WITH LOW 60S ACROSS EAST COLORADO AND MID 60S TO NEAR 70 FOR THE
REST OF THE AREA.
FOR TOMORROW...THE COLD FRONT IS EXPECTED TO STALL ACROSS THE AREA.
IN ADDITION TO THE FRONT...AN UPPER LEVEL DISTURBANCE WILL APPROACH
FROM THE WEST...PROVIDING EXTRA LIFT FOR SHOWER AND THUNDERSTORM
DEVELOPMENT. CHANCES FOR PRECIPITATION WILL BE MUCH HIGHER DURING
THE LATE AFTERNOON TO EVENING HOURS FOR A LARGER AREA. TEMPERATURES
BEHIND THE FRONT WILL BE NOTICEABLY COOLER WITH HIGHS IN THE UPPER
70S TO LOW 80S. ALONG AND AHEAD OF THE FRONT...TEMPERATURES WILL BE
WARM WITH HIGHS IN THE MID 80S TO LOW 90S WHERE DAYTIME HEATING
LASTS LONGER BEFORE CLOUDS AND CONVECTIVE ACTIVITY DEVELOPS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 1249 PM MDT MON SEP 9 2013
PATTERN CHANGE WILL OCCUR DURING THIS PERIOD AS THE UPPER RIDGE
WHICH HAS BEEN DOMINANT WILL SHIFT TO THE SOUTHEASTERN CONUS AND
TROUGH WHICH HAS BEEN OVER THE WEST WILL MOVE TO THE CENTRAL AND
NORTHERN ROCKIES. THIS WILL BRING NEAR TO BELOW NORMAL
TEMPERATURES AND OCCASIONAL CHANCES FOR PRECIPITATION TO THE AREA.
FIRST CHANCE FOR RAIN WILL OCCUR TUESDAY NIGHT WITH SHORTWAVE
TROUGH MOVING UP IN THE SOUTHWEST FLOW ALOFT. ANOTHER SHORTWAVE IS
FORECAST ON THURSDAY. BOTH SYSTEMS WILL HAVE PLENTIFUL MOISTURE TO
WORK WITH A TROPICAL CONNECTION TO THE BAJA. RAIN CHANCES CONTINUE
THROUGH THE WEEKEND AS THE UPPER LOW OPENS UP AND EVENTUALLY GETS
ENTRAINED IN THE NORTHERN STREAM. LATE IN THE PERIOD AN UPPER RIDGE
WILL BEGIN TO REBUILD BEHIND THE DEPARTING SYSTEM SIGNALING THE
RETURN OF WARM AND DRY CONDITIONS EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1127 AM MDT MON SEP 9 2013
VFR CONDITIONS CAN BE EXPECTED FOR THE NEXT 24 HOURS. A COLD FRONT
WAS MAKING ITS WAY TO THE SOUTH AND WILL BEGIN AFFECTING THE TAF
SITES TONIGHT. WITH THE FRONT DRAPED SOMEWHERE ACROSS THE
AREA...WIND DIRECTIONS WILL VARY THROUGHOUT THE NIGHT SO CONFIDENCE
IN THE WINDS IS LOWER THAN NORMAL. WIND SPEEDS TONIGHT SHOULD BE
LIGHT ONCE DAYTIME GUSTS ARE LOST THIS EVENING. A FEW ISOLATED
THUNDERSTORMS MAY DEVELOP ALONG THE FRONT THIS AFTERNOON AND
EVENING. HOWEVER...CONFIDENCE THAT CONVECTION WOULD BE CLOSE
TO TAF SITES WAS TOO LOW TO EVEN WARRANT A VCTS MENTION IN TAFS.
MOST OF THE THUNDERSTORM ACTIVITY SHOULD BE NORTHWEST OF TAF SITES.
&&
.FIRE WEATHER...
ISSUED AT 237 PM MDT MON SEP 9 2013
NEAR CRITICAL FIRE WEATHER CONDITIONS HAVE DEVELOPED ACROSS PORTIONS
OF THE REGION THIS AFTERNOON. HOT TEMPERATURES AND LOW DEWPOINTS
HAVE LEAD TO RELATIVE HUMIDITIES DROPPING OFF INTO THE 15-25 PERCENT
RANGE. WINDS HAVE BEEN GUSTY AND A FEW LOCATIONS WERE BARELY MEETING
CRITERIA. HOWEVER...WHETHER OR NOT THE CONDITIONS WOULD LAST THE
FULL THREE HOURS TO MEET WARNING CRITERIA HAS BEEN PROBLEMATIC AS
THE WINDS HAVE BEEN BOUNCING UP AND DOWN THIS AFTERNOON. IN
ADDITION...A SLIGHT RISE IN DEWPOINTS FROM SOUTH TO NORTH HAS BEEN
NOTED AS A MORE MOIST AIRMASS ADVECTS IN FROM THE SOUTH. AS A
RESULT...CONFIDENCE WAS NOT QUITE HIGH ENOUGH TO GO AHEAD AND
ISSUE A RED FLAG WARNING FOR REDWILLOW...HITCHCOCK...DECATUR...
HOXIE...SHERIDAN...THOMAS....ST FRANCIS AND SHERMAN COUNTIES. IF
IT BECOMES APPARENT THAT WINDS WILL STAY UP...A SHORT DURATION RED
FLAG WARNING MAY BE REQUIRED. WILL UPDATE THE FIRE WEATHER
FORECAST TO REFLECT THE LATEST TRENDS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...RRH
LONG TERM...024
AVIATION...RRH
FIRE WEATHER...RRH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1148 PM CDT Sun Sep 8 2013
.SHORT TERM...(This Evening through Monday)
Issued at 305 PM CDT SUN SEP 8 2013
At 2 PM, a weak surface trough was oriented from east to west across
northern Kansas on Sunday afternoon, co-located with the axis of
warmest 850 temperatures. A very weak front/outflow boundary with
minimal convergence in the low levels was stationary within 30 miles
of the Nebraska border as well, with a cluster of showers and
thunderstorms in extreme northeast Kansas and northwest Missouri.
Temperatures just to the south of the weak surface boundary have
become extremely warm, ranging from 99 to 104 degrees early this
afternoon, and while some drier air has mixed to the surface,
dewpoints remain in the lower to middle 60s. These conditions along
with the expectation for further heating through 4 PM have prompted
issuance of a heat advisory for heat index values in the 104 to 107
range.
Aside from the heat, potential for more vigorous thunderstorm
development is the other forecast focus today. The most recent runs
of the HRRR and NMM models continue to suggest thunderstorm
development on the warm side of the weak surface front by middle to
late afternoon, potentially linked to any outflow moving southwest
out of ongoing convection in NW Missouri. These storms are not
expected to be particularly organized or strong owing to only weak
to moderate CAPE and very weak vertical shear. However, it would
seem to be a rather favorable setup for microbursts given the dry
adiabatic to superadiabatic lapse rates from the surface to 700 hpa
and favorable downdraft CAPE. The primary uncertainty lies in
whether storms will actually develop over the deeply mixed airmass
as parcels would need to be lifted through a very deep mixed layer
before freely convecting. The best chance for storms would seem to
be northeast of a line from Belleville to Junction City to Ottawa.
Any storms should come to an end by 10 PM. Temperatures will fall
off nicely but a south breeze is expected to persist through the
night and will probably keep low temps in the low to mid 70s. Monday
will be quite hot once again, but with the upper ridge progressing
east of the area, 850 temps are forecast to drop by 2 to 3 degrees
from Sunday and highs may hold in the middle to upper 90s. Southwest
winds will be quite a bit stronger than Sunday with an increasing
pressure gradient. The southwest flow should also support greater
dry air advection into the forecast area which will probably support
very high fire danger with any dry vegetation.
Barjenbruch
.LONG TERM...(Monday Night through Sunday)
Issued at 305 PM CDT SUN SEP 8 2013
Monday night upper level trough progresses eastward through the
northern plains. As this system pushes into the Great Lakes region a
cold front will move southward into the region. Temperatures at 850
will cool significantly over the central plains as the shortwave
continues eastward and the upper high shifts into the OH river
valley. High temperatures reach the mid 90s area wide on Tuesday.
The front will approach the cwa on Tuesday evening and there is a
slight chance for showers and thunderstorms along the front mainly
across southern NE with an outside chance of reaching the northern
counties. Overnight Tuesday the front sags south into the cwa
increasing the chances for storms north of interstate 70s as the
progress of the front slows down. Due to cloud cover associated with
the possible precip high temperatures on Wednesday could remain in
the upper 80s to low 90s.
The front continues to slowly push south across the cwa therefore
have maintains pops through Friday. Convergence along the front and
upper level forcing appears to be rather weak, but cooler mid level
temps will allow for a weaker cap in place. Front exits the area
sometime on Thursday night or Friday as a shortwave digs southeast
through the eastern longwave trough. A surface high pressure will
build northeast of the region and likely control how far the front
is pushed southward. Once the front passes return flow isentropic
lift may generate precip mainly across central and western KS
possible spreading into our western counties. Next weekend another
front will possibly move into the central plains. Temperatures look
to gradually cool behind the front with high temperatures in the
upper 70s to low 80s by Friday, and low temperatures generally in
the upper 50s to low 60s.
&&
.AVIATION...(For the 06Z TAFs through 06Z Monday Night)
Issued at 1145 PM CDT SUN SEP 8 2013
Vfr conditions will prevail at all terminals through the fcst period.
Sustained south to southwest winds under 10 kts through 13z will
increase into the 13-15kt range by 15z with gusts over 20 kts thru
the remainder of the fcst period...although some decrease in
sustained speeds and gusts should occur aft 00Z/10.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barjenbruch
LONG TERM...Sanders
AVIATION...63
AREA FORECAST DISCUSSION
NWS JACKSON KY
553 PM EDT MON SEP 9 2013
.UPDATE...
ISSUED AT 553 PM EDT MON SEP 9 2013
A FEW SHOWERS AND THUNDERSTORMS HAVE DEVELOPED NORTHWARD INTO SOUTH
CENTRAL KENTUCKY...BASICALLY EASTERN WAYNE COUNTY/MCCREARY
COUNTY...NORTH INTO EASTERN PULASKI COUNTY. BASED ON SATELLITE...THIS
ACTIVITY SHOULD REMAIN CONFINED TO THESE AREAS OVER THE NEXT HOUR OR
TWO BEFORE WEAKENING AND DISSIPATING AS THE SUN GOES DOWN. THIS
SHOULD ALLOW ACTIVITY TO DIE OFF BY ROUGHLY 00Z. UPDATED NDFD GRIDS
TO REFINE THE POPS...BUT WILL NOT ISSUE A NEW ZFP WITH THE ISOLATED
NATURE OF THIS ACTIVITY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 340 PM EDT MON SEP 9 2013
18Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE IN PLACE OVER EAST KENTUCKY
WITH LOW PRESSURE FOUND OFF TO THE NORTHWEST. A DOME OF HIGHER
HEIGHTS IS BUILDING OVER THE REGION AND THIS HAS HELPED TO CONTRIBUTE
TO A VERY WARM LATE SUMMER DAY ACROSS EAST KENTUCKY WITH TEMPS
APPROACHING 90 DEGREES. PRETTY HIGH DEWPOINTS IN THE MID AND UPPER
60S ARE MAKING IT FEEL EVEN WARMER...IN ADDITION TO PROVIDING AN
UNCOMFORTABLE HUMIDITY LEVEL. HERE AT PEAK HEATING...A FEW OF THE CU
HAVE MANAGED TO GET DEEP ENOUGH THAT A SHOWER OR THUNDERSTORM WILL
BE POSSIBLE...MAINLY ALONG OUR SOUTHERN AND EASTERN BORDERS.
OTHERWISE...SKIES ARE MOSTLY CLEAR AND THE CU SHALLOW.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
DEPICTING A MODERATELY STRONG RIDGE PUSHING INTO THE LOWER OHIO
VALLEY AND ACROSS TO THE MID ATLANTIC COAST. THIS RIDGE WILL NOT BE
COMPLETELY FREE OF ENERGY OR PROHIBITIVELY WARM AT MID LEVELS...
THOUGH...SO ITS ABILITY TO PUT A CAP ON CONVECTION WILL BE LIMITED.
IN THIS KIND OF ENVIRONMENT...THE MESOSCALE WILL DOMINATE FOR WEATHER
SPECIFICS SO HAVE FAVORED A MORE SUBDUED VERSION OF THE NAM12 WITH
INPUT FROM THE HRRR IN THE NEAR TERM. ALSO FAVORED AN ENHANCED
DIURNAL TRACE FOR POPS.
SENSIBLE WEATHER WILL FEATURE MORE IN THE WAY OF PERSISTENCE THROUGH
WEDNESDAY MORNING. AT NIGHT...WE CAN EXPECT A FADE OUT OF THE
DAYTIME CLOUDS AND PATCHY FOG...LOCALLY DENSE IN THE VALLEYS...
DEVELOPING BY DAWN. HIGH DEWPOINTS WILL KEEP THERE FROM BEING MUCH OF
A RIDGE TO VALLEY TEMP SPLIT BOTH TONIGHT AND TUESDAY NIGHT. FOR THE
DAY TUESDAY...IT WILL BE ANOTHER WARM AND HUMID ONE WITH A SMALL
CHANCE OF SHOWERS AND THUNDERSTORMS DEVELOPING WITH PEAK HEATING...
DESPITE THE RIDGING ALOFT.
JUMP STARTED THE TD AND WIND GRIDS WITH CONSSHORT DATA THROUGH 12Z
TUESDAY AND THE CONSALL THEREAFTER. FOR TEMPERATURES...PREFERRED THE
OBS DATABASE AS A GUIDE FOR THE DIURNAL CURVE AND MODIFIED CONSALL
FOR MAX AND MIN TEMPS...TEMPERING THE TOO WARM GRIDDED MOS HIGHS ON
TUESDAY WITH SOME RAW MODEL OUTPUT. AS FOR POPS...ENDED UP PRETTY
CLOSE TO AN AVERAGE OF THE GUIDANCE THROUGH THE SHORT TERM PERIOD.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 245 PM EDT MON SEP 9 2013
THE MODELS ALL AGREE THAT WEDNESDAY AND THURSDAY WILL BE THE ACTIVE
DAYS OF THE EXTENDED PERIOD. A SERIES OF WEATHER SYSTEMS...BOTH
SURFACE FRONTS AND TROUGHS OF LOW PRESSURE ALOFT...WILL BRING
SHOWERS AND THUNDERSTORMS TO EASTERN KENTUCKY DURING THE MIDDLE OF
THE WEEK. THE MORE POTENT WEATHER MAKER WILL BE A SIGNIFICANT COLD
FRONT THAT IS EXPECTED TO MOVE ACROSS THE AREA THURSDAY INTO
THURSDAY EVENING. THE FRONT WILL LIKELY BE SLOWED UP A BIT BY THE
HIGH TERRAIN OF EAST KENTUCKY FOR IT FINALLY EXITS THE AREA THURSDAY
EVENING. ONCE THE FRONT IS OUT OF THE AREA...A LARGE AND WELL
DEFINED AREA OF HIGH PRESSURE WILL MIGRATE SOUTHWARD OUT OF CANADA
AND THEN THE OHIO VALLEY...BEFORE FINALLY SETTLING OVER THE EASTERN
CONUS FROM FRIDAY ONWARD. THE AIR MASS ASSOCIATED WITH THIS RIDGE
WILL BRING VERY UNSEASONABLY COOL TEMPERATURES TO THE REGION FRIDAY
AND SATURDAY. HIGHS ON FRIDAY AND SATURDAY WILL ONLY BE TOPPING OUT
IN THE LOW TO MID 70S...BEFORE REBOUNDING A BIT ON SUNDAY...WHEN
HIGHS IN THE UPPER 70S TO AROUND 80 ARE EXPECTED. THE
GFS...ECMWF...AND NAEFS MODELS ALL BEGIN THE PERIOD WITH A LARGE
TROUGH OF LOW PRESSURE ALOFT ACROSS THE EASTERN CONUS...WITH A
STRONG RIDGE OF HIGH PRESSURE SETTING UP OUT WEST. THE MIDDLE OF THE
WEEK WILL FEATURE WARM AND WET WEATHER...WHILE THE END OF THE WEEK
AND THE UPCOMING WEEKEND WILL BE VERY COOL AND DRY AND FALL LIKE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 150 PM EDT MON SEP 9 2013
VFR CONDITIONS WILL DOMINATE UNTIL 6-8Z TONIGHT WHEN FOG IS ONCE
AGAIN EXPECTED TO FORM. CANNOT COMPLETELY RULE OUT SOME LOWER CIGS OR
VIS SHOULD A STRAY SHOWER OR STORM POP UP NEAR A TAF SITE THIS
AFTERNOON...BUT THE CHANCES ARE PRETTY LOW. THE FOG WILL BURN OFF
TOMORROW MORNING WITH A SIMILAR TYPE OF DAY AND LOW CONVECTIVE
CHANCES AS WE HAVE TODAY. WINDS THROUGHOUT THE PERIOD WILL BE LIGHT
AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
340 PM EDT MON SEP 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 340 PM EDT MON SEP 9 2013
18Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE IN PLACE OVER EAST KENTUCKY
WITH LOW PRESSURE FOUND OFF TO THE NORTHWEST. A DOME OF HIGHER
HEIGHTS IS BUILDING OVER THE REGION AND THIS HAS HELPED TO CONTRIBUTE
TO A VERY WARM LATE SUMMER DAY ACROSS EAST KENTUCKY WITH TEMPS
APPROACHING 90 DEGREES. PRETTY HIGH DEWPOINTS IN THE MID AND UPPER
60S ARE MAKING IT FEEL EVEN WARMER...IN ADDITION TO PROVIDING AN
UNCOMFORTABLE HUMIDITY LEVEL. HERE AT PEAK HEATING...A FEW OF THE CU
HAVE MANAGED TO GET DEEP ENOUGH THAT A SHOWER OR THUNDERSTORM WILL
BE POSSIBLE...MAINLY ALONG OUR SOUTHERN AND EASTERN BORDERS.
OTHERWISE...SKIES ARE MOSTLY CLEAR AND THE CU SHALLOW.
THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM
DEPICTING A MODERATELY STRONG RIDGE PUSHING INTO THE LOWER OHIO
VALLEY AND ACROSS TO THE MID ATLANTIC COAST. THIS RIDGE WILL NOT BE
COMPLETELY FREE OF ENERGY OR PROHIBITIVELY WARM AT MID LEVELS...
THOUGH...SO ITS ABILITY TO PUT A CAP ON CONVECTION WILL BE LIMITED.
IN THIS KIND OF ENVIRONMENT...THE MESOSCALE WILL DOMINATE FOR WEATHER
SPECIFICS SO HAVE FAVORED A MORE SUBDUED VERSION OF THE NAM12 WITH
INPUT FROM THE HRRR IN THE NEAR TERM. ALSO FAVORED AN ENHANCED
DIURNAL TRACE FOR POPS.
SENSIBLE WEATHER WILL FEATURE MORE IN THE WAY OF PERSISTENCE THROUGH
WEDNESDAY MORNING. AT NIGHT...WE CAN EXPECT A FADE OUT OF THE
DAYTIME CLOUDS AND PATCHY FOG...LOCALLY DENSE IN THE VALLEYS...
DEVELOPING BY DAWN. HIGH DEWPOINTS WILL KEEP THERE FROM BEING MUCH OF
A RIDGE TO VALLEY TEMP SPLIT BOTH TONIGHT AND TUESDAY NIGHT. FOR THE
DAY TUESDAY...IT WILL BE ANOTHER WARM AND HUMID ONE WITH A SMALL
CHANCE OF SHOWERS AND THUNDERSTORMS DEVELOPING WITH PEAK HEATING...
DESPITE THE RIDGING ALOFT.
JUMP STARTED THE TD AND WIND GRIDS WITH CONSSHORT DATA THROUGH 12Z
TUESDAY AND THE CONSALL THEREAFTER. FOR TEMPERATURES...PREFERRED THE
OBS DATABASE AS A GUIDE FOR THE DIURNAL CURVE AND MODIFIED CONSALL
FOR MAX AND MIN TEMPS...TEMPERING THE TOO WARM GRIDDED MOS HIGHS ON
TUESDAY WITH SOME RAW MODEL OUTPUT. AS FOR POPS...ENDED UP PRETTY
CLOSE TO AN AVERAGE OF THE GUIDANCE THROUGH THE SHORT TERM PERIOD.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 245 PM EDT MON SEP 9 2013
THE MODELS ALL AGREE THAT WEDNESDAY AND THURSDAY WILL BE THE ACTIVE
DAYS OF THE EXTENDED PERIOD. A SERIES OF WEATHER SYSTEMS...BOTH
SURFACE FRONTS AND TROUGHS OF LOW PRESSURE ALOFT...WILL BRING
SHOWERS AND THUNDERSTORMS TO EASTERN KENTUCKY DURING THE MIDDLE OF
THE WEEK. THE MORE POTENT WEATHER MAKER WILL BE A SIGNIFICANT COLD
FRONT THAT IS EXPECTED TO MOVE ACROSS THE AREA THURSDAY INTO
THURSDAY EVENING. THE FRONT WILL LIKELY BE SLOWED UP A BIT BY THE
HIGH TERRAIN OF EAST KENTUCKY FOR IT FINALLY EXITS THE AREA THURSDAY
EVENING. ONCE THE FRONT IS OUT OF THE AREA...A LARGE AND WELL
DEFINED AREA OF HIGH PRESSURE WILL MIGRATE SOUTHWARD OUT OF CANADA
AND THEN THE OHIO VALLEY...BEFORE FINALLY SETTLING OVER THE EASTERN
CONUS FROM FRIDAY ONWARD. THE AIR MASS ASSOCIATED WITH THIS RIDGE
WILL BRING VERY UNSEASONABLY COOL TEMPERATURES TO THE REGION FRIDAY
AND SATURDAY. HIGHS ON FRIDAY AND SATURDAY WILL ONLY BE TOPPING OUT
IN THE LOW TO MID 70S...BEFORE REBOUNDING A BIT ON SUNDAY...WHEN
HIGHS IN THE UPPER 70S TO AROUND 80 ARE EXPECTED. THE
GFS...ECMWF...AND NAEFS MODELS ALL BEGIN THE PERIOD WITH A LARGE
TROUGH OF LOW PRESSURE ALOFT ACROSS THE EASTERN CONUS...WITH A
STRONG RIDGE OF HIGH PRESSURE SETTING UP OUT WEST. THE MIDDLE OF THE
WEEK WILL FEATURE WARM AND WET WEATHER...WHILE THE END OF THE WEEK
AND THE UPCOMING WEEKEND WILL BE VERY COOL AND DRY AND FALL LIKE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 150 PM EDT MON SEP 9 2013
VFR CONDITIONS WILL DOMINATE UNTIL 6-8Z TONIGHT WHEN FOG IS ONCE
AGAIN EXPECTED TO FORM. CANNOT COMPLETELY RULE OUT SOME LOWER CIGS OR
VIS SHOULD A STRAY SHOWER OR STORM POP UP NEAR A TAF SITE THIS
AFTERNOON...BUT THE CHANCES ARE PRETTY LOW. THE FOG WILL BURN OFF
TOMORROW MORNING WITH A SIMILAR TYPE OF DAY AND LOW CONVECTIVE
CHANCES AS WE HAVE TODAY. WINDS THROUGHOUT THE PERIOD WILL BE LIGHT
AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
150 PM EDT MON SEP 9 2013
.UPDATE...
ISSUED AT 145 PM EDT MON SEP 9 2013
UPDATED THE GRIDS TO FINE TUNE MAX TEMPS AND HOURLY CURVES FOR T AND
TD THROUGH EVENING. ALSO TOUCHED UP THE SKY COVER AND POP GRIDS PER
THE LATEST OBS AND TRENDS. BETTER CU DEVELOPMENT IS LOCATED OVER THE
HIGHER TERRAIN IN THE SOUTHEAST AND ALSO WEST OF INTERSTATE 75...SOUTH
AND INTO TENNESSEE. THE HRRR SHOWS SOME LIMITED DEVELOPMENT LATE THIS
AFTERNOON OVER THAT FIRST AREA OF MORE ENHANCED CU...SO WOULD NOT
RULE CONVECTION OUT COMPLETELY. MEANWHILE...THE NAM12 SHOWS SOME MORE
SUBSTANTIAL DEVELOPMENT THIS AFTERNOON ACROSS THE CUMBERLAND VALLEY.
AM NOT SEEING MUCH SUPPORT FOR THIS...THOUGH...SO HAVE DISCOUNTED IT
BUT...WILL KEEP POPS IN THE 10 TO 15 PERCENT THROUGH THIS AREA AND
POINTS EAST DURING THE REMAINDER OF THE AFTERNOON. UPDATES HAVE BEEN
SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 1045 AM EDT MON SEP 9 2013
14Z SFC ANALYSIS SHOWS WEAK HIGH PRESSURE OVER EAST KENTUCKY AS THE
EARLIER FRONT HAS DISSIPATED. WITH RIDGING BUILDING IN ALOFT...EXPECT
CONVECTION TO BE SUPPRESSED TODAY...BUT WILL HAVE TO WATCH THE HIGHER
TERRAIN NEAR THE VIRGINIA BORDER AS THE ONE PLACE THAT MAY BE THE
EXCEPTION. CURRENTLY...ALL IS QUIET ACROSS EAST KENTUCKY AS THE EARLY
MORNING FOG HAS BURNED OFF AND SKIES ARE MOSTLY CLEAR. TEMPERATURES
ARE RESPONDING NICELY TO THE SUNSHINE WITH READINGS CLIMBING INTO THE
MID 70S IN MOST LOCATIONS...THOUGH THIS RISE IS A BIT DELAYED IN THE
PLACES WHERE THE FOG JUST RECENTLY CLEARED. MEANWHILE...DEWPOINTS
REMAIN ON THE HIGH AND UNCOMFORTABLE SIDE...GENERALLY IN THE MID TO
UPPER 60S. THE FORECAST IS ON TRACK SO HAVE UPDATED THE ZONES TO
REMOVE THE MORNING FOG WORDING AND ADJUSTED THE SKY...T...AND TD
GRIDS PER THE LATEST OBSERVATIONS AND TRENDS. THESE GRIDS HAVE BEEN
SENT THE THE NDFD AND WEB SERVES.
UPDATE ISSUED AT 730 AM EDT MON SEP 9 2013
UPDATED THE FORECAST TO BETTER REFLECT CURRENT CONDITIONS AND MODEL
TRENDS. ONLY HAD TO MAKE SOME MINOR ADJUSTMENTS TO TEMPERATURES AND
DEWPOINTS FOR THE FIRST FEW HOURS OF THE FORECAST. THE REST OF THE
FORECAST IS ON TRACK.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 308 AM EDT MON SEP 9 2013
THE MODELS ARE IN GOOD AGREEMENT WITH THE UPPER AIR AND SURFACE
PATTERNS...BUT THEY DIFFER ON WHETHER OR NOT THAT THIS PATTER WILL BE
ABLE TO PRODUCE ANY SHOWERS OR THUNDERSTORMS. THE GFS IS THE DRIEST
OF THE MODELS AND IT ALSO INITIALIZES THE BEST. SO DECIDED TO GO WITH
THE GFS AS THE MODEL OF THE DAY AND HAVE TAKEN OUT ANY PRECIPITATION
FOR TODAY ALONG THE VIRGINIA BORDER. FOR TUESDAY...LEFT SOME ISOLATED
THUNDERSTORMS IN THE FORECAST...HOWEVER CONFIDENCE IN GETTING THEM IS
PRETTY LOW. THE ATMOSPHERE WILL CERTAINLY BE UNSTABLE ENOUGH ON
TUESDAY...THE THING THAT IS MISSING IS THE TRIGGER TO GET SOME STORMS
GOING. FOR TEMPERATURES...JUST NUDGED THEM TOWARD THE MODEL BLEND. IF
NO STORMS DEVELOP ON TUESDAY...THEN THE TEMPERATURES COULD ACTUALLY
GET A LITTLE LOWER.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 402 AM EDT MON SEP 9 2013
THE MODELS REMAIN IN GENERAL AGREEMENT WITH THE LONG WAVE PATTERN
THROUGH THE PERIOD...WITH AN UPPER LEVEL RIDGE POISED FROM THE MID-
ATLANTIC STATES THROUGH THE TENNESSEE VALLEY. FASTER FLOW ACROSS THE
NORTHERN PLAINS WILL ESCORT IN A DEEPENING SHORT WAVE TROUGH THAT
WILL SWING THROUGH THE GREAT LAKES AND NORTHERN OHIO VALLEY THROUGH
THURSDAY...SHUNTING AND WEAKENING THE RIDGE BACK TOWARDS THE PLAINS.
THIS WILL ALLOW A COLD FRONT TO DROP SOUTHEAST INTO THE TENNESSEE
VALLEY BY FRIDAY...BRINGING AN END TO THE HEAT AND HUMIDITY.
TROUGHING WILL THEN LINGER ACROSS NEW ENGLAND THROUGH THE FIRST PART
OF THE WEEKEND...BEFORE THE NEXT DEEPER SHORT WAVE TROUGH MOVES
ACROSS THE NORTHERN GREAT LAKES. THIS WILL HELP FLATTEN OUT THE FLOW
OUT AHEAD OF IT AND ALLOW FOR AT LEAST SOME MODEST RIDGING TO BUILD
BACK INTO THE LOWER MISSISSIPPI VALLEY THROUGH THE END OF THE WEEK.
ISOLATED TO SCATTERED CONVECTION WILL POP UP ACROSS EASTERN KENTUCKY
THROUGH WEDNESDAY...AS THE UPPER LEVEL RIDGE BEGINS TO BREAK DOWN AND
PLENTY OF HEAT AND HUMIDITY LINGER. THE BEST CHANCE OF PRECIPITATION
CONTINUES TO BE CENTERED AROUND THURSDAY AS THE FRONT APPROACHES AND
EVENTUALLY MOVES THROUGH THE AREA BY THURSDAY EVENING. BY FRIDAY...AN
AREA OF SURFACE HIGH PRESSURE WILL BE BUILDING IN FROM THE
NORTH...BRINGING DRY WEATHER AND A WELCOMED RELIEF FROM THE HUMIDITY.
HIGHS IN THE MID TO UPPER 80S THROUGH THURSDAY WILL DROP BACK DOWN
INTO THE 70S FOR THE WEEKEND...WITH LOWS MAINLY IN THE 50S...ALTHOUGH
SOME OF THE MORE SHELTERED VALLEYS MAY SEE 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 150 PM EDT MON SEP 9 2013
VFR CONDITIONS WILL DOMINATE UNTIL 6-8Z TONIGHT WHEN FOG IS ONCE
AGAIN EXPECTED TO FORM. CANNOT COMPLETELY RULE OUT SOME LOWER CIGS OR
VIS SHOULD A STRAY SHOWER OR STORM POP UP NEAR A TAF SITE THIS
AFTERNOON...BUT THE CHANCES ARE PRETTY LOW. THE FOG WILL BURN OFF
TOMORROW MORNING WITH A SIMILAR TYPE OF DAY AND LOW CONVECTIVE
CHANCES AS WE HAVE TODAY. WINDS THROUGHOUT THE PERIOD WILL BE LIGHT
AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JJ
LONG TERM...GEOGERIAN
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
303 PM EDT MON SEP 9 2013
.SYNOPSIS...
HEAT AND HUMIDITY WILL BUILD THIS WEEK BEFORE A STRONG COLD FRONT
ON THURSDAY USHERS IN MUCH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH TUESDAY/...
QUICK UPDATE MADE TO ACCOUNT FOR CURRENT SHWRS/TSTMS SLGTLY
EARLIER THAN IN GOING FCST. PREV DISCUSSION FOLLOWS...
A WARM FRONT IS STILL PROGGED TO LIFT NORTH ACROSS THE REGION
LATER THIS AFTERNOON BUT QUESTION REMAINS ON HOW MUCH CONVECTION
WE WILL SEE WITH IT. DEWPOINTS HAVE ALREADY BEGUN TO REBOUND INTO
THE MID 60S OVER EASTERN OHIO AND NORTHERN WEST VIRGINIA BUT
INSTABILITY REMAINS ELEVATED PER THE MOST RECENT MESOANALYSIS.
STILL THINK THAT...WITH THE HELP OF A PASSING UPPER- LEVEL
SHORTWAVE THAT HAS SUPPORTED SOME SHOWERS AND STORMS OVER
MICHIGAN...THERE COULD BE AT LEAST SCATTERED SHOWERS AND STORMS
OVER OUR REGION TODAY. WHILE THERE ARE A FEW DIFFERENCES IN THE
DETERMINISTIC SOLUTIONS...THE RAP AND HRRR SEEM TO SUGGEST THAT
THE NORTHERN ZONES MAY HAVE THE BEST CHANCE FOR PRECIP. WITH THIS
IN MIND...KEPT THE CHANCE POPS FOCUSED IN THIS AREA AND CONTINUED
A SLIGHT CHANCE EVERYWHERE ELSE. OF COURSE...THIS DOES NOT
COMPLETELY RULE OUT THE CHANCE FOR THUNDERSTORMS FARTHER
SOUTH...SINCE THOSE COUNTIES ARE EXPERIENCING MORE-RAPID SURFACE
HEATING DUE TO LESS CLOUD COVER.
HIGH PRESSURE WILL BUILD EASTWARD TONIGHT...AND WITH IT WILL RETURN
VERY WARM AND MUGGY WEATHER. HIGHS ARE FORECAST TO BE WELL ABOVE
SEASONAL AVERAGES TOMORROW...WITH MOST PLACES SEEING MID 80S TO
EVEN 90. WHILE THIS COULD LEAD TO PLENTY OF SURFACE
INSTABILITY...THERE DOES NOT SEEM TO BE ANY FOCUS FOR CONVECTION.
THE ONLY CONSIDERATION IS THE HIGHER ELEVATIONS...WHERE A FEW
THUNDERSTORMS COULD DEVELOP WITH THE HELP OF OROGRAPHIC LIFT. AT
THIS TIME THOUGH...MAINTAINED A DRY FORECAST FOR ALL OF TUESDAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A VERY MOIST AND UNSTABLE AMS WILL RMN IN PLACE THRU THU OWING TO
PERSISTENT SWLY LOW-LVL FLOW. TUE NGT AND WED NGT WILL BOTH SEE
MINIMA IN THE 60S...WITH MINIMA APRCHG 70 TUE NGT.
SHWRS AND TSTMS WILL INCR IN CVRG ON WED AS A LOW-AMPLITUDE SHRTWV
TROF APRCHS AND UPR RDG FLATTENS. CLD CVR XPCD TO BE SUBSTANTIAL
OWING TO UNSTABLE AMS...WHICH MAY LMT MAXIMA SLGTLY COMPARED TO
TUE. HOWEVER...MAXIMA STILL XPCD TO REACH MID-UPR 80S.
LACK OF STRONG MID-LVL FLOW ON WED WILL YIELD RATHER ANEMIC SHEAR
DESPITE MDT INSTBY. WITH PWATS FCSTD IN EXCESS OF 1.8 IN...MAIN
CONCERN WILL BE FOR FLOODING FROM SLOW-MOVG TSTMS PRODUCING VERY
HVY RAIN.
BECAUSE THE FLY ALWAYS FINDS ITS OINTMENT...THE 12Z/09 NAM12 HAS
OFFERED A MUCH SLOWER ARRRIVAL OF THE CDFNT THAT WAS XPCD TO
ARRIVE ON THU. GFS/ECMWF STILL AGREE ON A MID-LATE DAY FROPA WHILE
NAM SUGGESTS AN ARRIVAL OVNGT THU NGT.
GIVEN CONSISTENCY OF GFS ENSEMBLE WITH GFS/ECMWF SOLUTIONS...THE
NAM12 SOLUTION WILL BE DEEMED AN OUTLIER...AND FCST TIMING WILL BE
MAINTAINED WITH FROPA DURG THU. WITH FAVORABLE TIMING OF FROPA AND
MINIMAL OVNGT CNVCTN XPCD...THU APPEARS QUITE FAVORABLE FOR WDSPRD
TSTMS ALONG THE ADVCG BNDRY. THUS...POPS WERE INCRD TO LKLY AS THE
BNDRY CROSSES AND MAXIMA WERE INCRD SLGTLY FOLLOWING THE TREND OF
LATEST GUIDANCE.
GUIDANCE ALSO SUGGESTS POST-FRONTAL CLDS WILL INVADE THU NGT AHD
OF SECONDARY PRES SURGE. CLD CVR WAS INCRD SGFNTLY LATE THU NGT...
WHICH WILL SLOW THE XPCD COOLING. THUS...THU NGT MINIMA WERE INCRD
A FEW DEG F.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A STG CDFNT WL CROSS THE RGN THU CONTG THE SHWR/TSTM CHCS. HIGH
PRES IS THEN EXPD TO BLD IN THRU THE WKEND. AFT FROPA...850MB
TEMPS DROP INTO THE SINGLE DIGITS...BOTTOMING OUT ARND 2 DEG C FRI
NGT. THIS WL BRING WELL BLO AVG TEMP FRI THRU SUN...ALTHOUGH SOME
MODERATION CAN BE EXPD SUN AS THE FLOW TURNS SRLY AND THE HIGH
SHIFTS EWD.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
GENERAL VFR IS EXPECTED TO CONTINUE THROUGH MUCH OF THE PERIOD. A
LIFTING WARM FRONT WILL STILL PROVIDE THE CHANCE FOR SHOWERS AND
THUNDERSTORMS THIS AFTERNOON BUT AT THIS POINT COVERAGE IS
EXPECTED TO REMAIN SMALL. WILL MENTION VCTS IN THE SITES NORTH OF
PIT WHERE THE MODEL GUIDANCE CONTINUES TO SUGGEST THE GREATEST
PROBABILITY AND WILL MAINTAIN SCATTERED/BROKEN MID DECK EVERYWHERE
ELSE. ONE THING TO NOTE IS ANY TAF SITE THAT DOES EXPERIENCE A
SHOWER OR STORM WILL LIKELY EXPERIENCE IFR VISIBILITIES WITH
INCREASING LOW LEVEL MOISTURE.
WIND WILL GRADUALLY SHIFT TO SOUTHWESTERLY THROUGH THE AFTERNOON.
HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT...ENDING THE THREAT FOR
PRECIPITATION. WITH THE LOW LEVELS REMAINING MOIST...DO ANTICIPATE
SOME FOG IN SPOTS BUT LINGERING CLOUDS AND ELEVATED WIND MAY KEEP
IT MINIMAL.
.OUTLOOK.../MONDAY NIGHT THROUGH SATURDAY/...
GENERAL VFR IS EXPECTED UNTIL A COLD FRONT APPROACHES FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
UPDATE...KRAMAR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
157 PM EDT MON SEP 9 2013
.SYNOPSIS...
HEAT AND HUMIDITY WILL BUILD THIS WEEK BEFORE A STRONG COLD FRONT
ON THURSDAY USHERS IN MUCH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH TUESDAY/...
A WARM FRONT IS STILL PROGGED TO LIFT NORTH ACROSS THE REGION
LATER THIS AFTERNOON BUT QUESTION REMAINS ON HOW MUCH CONVECTION WE
WILL SEE WITH IT. DEWPOINTS HAVE ALREADY BEGUN TO REBOUND INTO THE
MID 60S OVER EASTERN OHIO AND NORTHERN WEST VIRGINIA BUT INSTABILITY
REMAINS ELEVATED PER THE MOST RECENT MESOANALYSIS. STILL THINK
THAT...WITH THE HELP OF A PASSING UPPER-LEVEL SHORTWAVE THAT HAS
SUPPORTED SOME SHOWERS AND STORMS OVER MICHIGAN...THERE COULD BE
AT LEAST SCATTERED SHOWERS AND STORMS OVER OUR REGION TODAY. WHILE
THERE ARE A FEW DIFFERENCES IN THE DETERMINISTIC SOLUTIONS...THE
RAP AND HRRR SEEM TO SUGGEST THAT THE NORTHERN ZONES MAY HAVE THE
BEST CHANCE FOR PRECIP. WITH THIS IN MIND...KEPT THE CHANCE POPS
FOCUSED IN THIS AREA AND CONTINUED A SLIGHT CHANCE EVERYWHERE
ELSE. OF COURSE...THIS DOES NOT COMPLETELY RULE OUT THE CHANCE FOR
THUNDERSTORMS FARTHER SOUTH...SINCE THOSE COUNTIES ARE EXPERIENCING
MORE-RAPID SURFACE HEATING DUE TO LESS CLOUD COVER.
HIGH PRESSURE WILL BUILD EASTWARD TONIGHT...AND WITH IT WILL RETURN
VERY WARM AND MUGGY WEATHER. HIGHS ARE FORECAST TO BE WELL ABOVE
SEASONAL AVERAGES TOMORROW...WITH MOST PLACES SEEING MID 80S TO
EVEN 90. WHILE THIS COULD LEAD TO PLENTY OF SURFACE
INSTABILITY...THERE DOES NOT SEEM TO BE ANY FOCUS FOR CONVECTION.
THE ONLY CONSIDERATION IS THE HIGHER ELEVATIONS...WHERE A FEW
THUNDERSTORMS COULD DEVELOP WITH THE HELP OF OROGRAPHIC LIFT. AT
THIS TIME THOUGH...MAINTAINED A DRY FORECAST FOR ALL OF TUESDAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A VERY MOIST AND UNSTABLE AMS WILL RMN IN PLACE THRU THU OWING TO
PERSISTENT SWLY LOW-LVL FLOW. TUE NGT AND WED NGT WILL BOTH SEE
MINIMA IN THE 60S...WITH MINIMA APRCHG 70 TUE NGT.
SHWRS AND TSTMS WILL INCR IN CVRG ON WED AS A LOW-AMPLITUDE SHRTWV
TROF APRCHS AND UPR RDG FLATTENS. CLD CVR XPCD TO BE SUBSTANTIAL
OWING TO UNSTABLE AMS...WHICH MAY LMT MAXIMA SLGTLY COMPARED TO
TUE. HOWEVER...MAXIMA STILL XPCD TO REACH MID-UPR 80S.
LACK OF STRONG MID-LVL FLOW ON WED WILL YIELD RATHER ANEMIC SHEAR
DESPITE MDT INSTBY. WITH PWATS FCSTD IN EXCESS OF 1.8 IN...MAIN
CONCERN WILL BE FOR FLOODING FROM SLOW-MOVG TSTMS PRODUCING VERY
HVY RAIN.
BECAUSE THE FLY ALWAYS FINDS ITS OINTMENT...THE 12Z/09 NAM12 HAS
OFFERED A MUCH SLOWER ARRRIVAL OF THE CDFNT THAT WAS XPCD TO
ARRIVE ON THU. GFS/ECMWF STILL AGREE ON A MID-LATE DAY FROPA WHILE
NAM SUGGESTS AN ARRIVAL OVNGT THU NGT.
GIVEN CONSISTENCY OF GFS ENSEMBLE WITH GFS/ECMWF SOLUTIONS...THE
NAM12 SOLUTION WILL BE DEEMED AN OUTLIER...AND FCST TIMING WILL BE
MAINTAINED WITH FROPA DURG THU. WITH FAVORABLE TIMING OF FROPA AND
MINIMAL OVNGT CNVCTN XPCD...THU APPEARS QUITE FAVORABLE FOR WDSPRD
TSTMS ALONG THE ADVCG BNDRY. THUS...POPS WERE INCRD TO LKLY AS THE
BNDRY CROSSES AND MAXIMA WERE INCRD SLGTLY FOLLOWING THE TREND OF
LATEST GUIDANCE.
GUIDANCE ALSO SUGGESTS POST-FRONTAL CLDS WILL INVADE THU NGT AHD
OF SECONDARY PRES SURGE. CLD CVR WAS INCRD SGFNTLY LATE THU NGT...
WHICH WILL SLOW THE XPCD COOLING. THUS...THU NGT MINIMA WERE INCRD
A FEW DEG F.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A STG CDFNT WL CROSS THE RGN THU CONTG THE SHWR/TSTM CHCS. HIGH
PRES IS THEN EXPD TO BLD IN THRU THE WKEND. AFT FROPA...850MB
TEMPS DROP INTO THE SINGLE DIGITS...BOTTOMING OUT ARND 2 DEG C FRI
NGT. THIS WL BRING WELL BLO AVG TEMP FRI THRU SUN...ALTHOUGH SOME
MODERATION CAN BE EXPD SUN AS THE FLOW TURNS SRLY AND THE HIGH
SHIFTS EWD.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
GENERAL VFR IS EXPECTED TO CONTINUE THROUGH MUCH OF THE PERIOD. A
LIFTING WARM FRONT WILL STILL PROVIDE THE CHANCE FOR SHOWERS AND
THUNDERSTORMS THIS AFTERNOON BUT AT THIS POINT COVERAGE IS
EXPECTED TO REMAIN SMALL. WILL MENTION VCTS IN THE SITES NORTH OF
PIT WHERE THE MODEL GUIDANCE CONTINUES TO SUGGEST THE GREATEST
PROBABILITY AND WILL MAINTAIN SCATTERED/BROKEN MID DECK EVERYWHERE
ELSE. ONE THING TO NOTE IS ANY TAF SITE THAT DOES EXPERIENCE A
SHOWER OR STORM WILL LIKELY EXPERIENCE IFR VISIBILITIES WITH
INCREASING LOW LEVEL MOISTURE.
WIND WILL GRADUALLY SHIFT TO SOUTHWESTERLY THROUGH THE AFTERNOON.
HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT...ENDING THE THREAT FOR
PRECIPITATION. WITH THE LOW LEVELS REMAINING MOIST...DO ANTICIPATE
SOME FOG IN SPOTS BUT LINGERING CLOUDS AND ELEVATED WIND MAY KEEP
IT MINIMAL.
.OUTLOOK.../MONDAY NIGHT THROUGH SATURDAY/...
GENERAL VFR IS EXPECTED UNTIL A COLD FRONT APPROACHES FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
34/KRAMAR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1219 PM EDT MON SEP 9 2013
.SYNOPSIS...
HEAT AND HUMIDITY WILL BUILD THIS WEEK BEFORE THE PASSAGE OF A
STRONG COLD FRONT THURSDAY USHERS IN MUCH COOLER TEMPERATURES.
&&
.NEAR TERM /THROUGH TUESDAY/...
A WARM FRONT IS STILL PROGGED TO LIFT NORTH ACROSS THE REGION
LATER THIS AFTERNOON BUT QUESTION REMAINS ON HOW MUCH CONVECTION WE
WILL SEE WITH IT. DEWPOINTS HAVE ALREADY BEGUN TO REBOUND INTO THE
MID 60`S OVER EASTERN OHIO AND NORTHERN WEST VIRGINIA BUT
INSTABILITY REMAINS ELEVATED PER THE MOST RECENT MESOANALYSIS.
STILL THINK THAT WITH THE HELP OF A PASSING UPPER LEVEL
SHORTWAVE...THAT HAS SUPPORTED SOME SHOWERS AND STORMS OVER
MICHIGAN...THERE COULD BE AT LEAST SCATTERED SHOWERS AND STORMS
OVER OUR REGION TODAY. WHILE THERE ARE A FEW DIFFERENCES IN THE
DETERMINISTIC SOLUTIONS...THE RAP AND HRRR SEEM TO SUGGEST THAT
THE NORTHERN ZONES MAY HAVE THE BEST CHANCE FOR PRECIP. WITH THIS
IN MIND...KEPT THE CHANCE POPS FOCUSED IN THIS AREA AND CONTINUED
A SLIGHT CHANCE EVERYWHERE ELSE. OF COURSE...THIS DOES NOT
COMPLETELY RULE OUT THE CHANCE FOR THUNDERSTORMS FURTHER SOUTH
SINCE THOSE COUNTIES ARE EXPERIENCING MORE RAPID SURFACE HEATING
DUE TO LESS CLOUD COVER.
RIDGE OF HIGH PRESSURE WILL BUILD EASTWARD TONIGHT AND WITH IT
WILL RETURN VERY WARM AND MUGGY WEATHER. HIGHS ARE FORECAST TO BE
WELL ABOVE SEASONAL AVERAGES TOMORROW...WITH MOST PLACES SEEING
MID 80`S TO EVEN 90. WHILE THIS COULD LEAD TO PLENTY OF SURFACE
INSTABILITY...THERE DOESN`T SEEM TO BE ANY FOCUS FOR CONVECTION.
THE ONLY CONSIDERATION IS THE HIGHER ELEVATIONS WHERE A FEW
THUNDERSTORMS COULD DEVELOP WITH THE HELP OF OROGRAPHIC LIFT. AT THIS
TIME THOUGH...MAINTAINED A DRY FORECAST FOR ALL OF TUESDAY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
RIDGE BREAKS DOWN WED...AS WEAK SHORTWAVE TROUGH SWINGS THROUGH.
THIS WILL PROVIDE A BETTER CHANCE FOR ACTIVITY WED AFTERNOON.
STILL TOUGH TO FIND A REAL STRONG TRIGGER...BUT THE ATMOSPHERE
REMAINS UNSTABLE AND THE UPPER LEVEL DISTURBANCE MAY BE ENOUGH TO
GET ACTIVITY GOING. SHEAR IS WEAK WED...SO NOT AS CONCERNED WITH
SEVERE POTENTIAL...HOWEVER WITH PWATS APPROACHING 1.8 INCHES AND
VERY LITTLE FLOW...THE POTENTIAL EXISTS FOR THE DEVELOPMENT OF
SLOW MOVING...HEAVY RAIN PRODUCING STORMS. CLOUD COVER WILL BE
CRUCIAL AS CONVECTIVE TEMPS ARE HIGH.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
A STG CDFNT WL CROSS THE RGN THU CONTG THE SHWR/TSTM CHCS. HIGH
PRES IS THEN EXPD TO BLD IN THRU THE WKEND. AFT FROPA...850MB
TEMPS DROP INTO THE SINGLE DIGITS...BOTTOMING OUT ARND 2 DEG C FRI
NGT. THIS WL BRING WELL BLO AVG TEMP FRI THRU SUN...ALTHOUGH SOME
MODERATION CAN BE EXPD SUN AS THE FLOW TURNS SRLY AND THE HIGH
SHIFTS EWD.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
GENERAL VFR IS EXPECTED TO CONTINUE THROUGH MUCH OF THE PERIOD. A
LIFTING WARM FRONT WILL STILL PROVIDE THE CHANCE FOR SHOWERS AND
THUNDERSTORMS THIS AFTERNOON BUT AT THIS POINT COVERAGE IS
EXPECTED TO REMAIN SMALL. WILL MENTION VCTS IN THE SITES NORTH OF
PIT WHERE THE MODEL GUIDANCE CONTINUES TO SUGGEST THE GREATEST
PROBABILITY AND WILL MAINTAIN SCATTERED/BROKEN MID DECK EVERYWHERE
ELSE. ONE THING TO NOTE IS ANY TAF SITE THAT DOES EXPERIENCE A
SHOWER OR STORM WILL LIKELY EXPERIENCE IFR VISIBILITIES WITH
INCREASING LOW LEVEL MOISTURE.
WIND WILL GRADUALLY SHIFT TO SOUTHWESTERLY THROUGH THE AFTERNOON.
HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT...ENDING THE THREAT FOR
PRECIPITATION. WITH THE LOW LEVELS REMAINING MOIST...DO ANTICIPATE
SOME FOG IN SPOTS BUT LINGERING CLOUDS AND ELEVATED WIND MAY KEEP
IT MINIMAL.
.OUTLOOK.../MONDAY NIGHT THROUGH SATURDAY/...
GENERAL VFR IS EXPECTED UNTIL A COLD FRONT APPROACHES FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
737 PM EDT TUE SEP 10 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...A SHORTWAVE MOVING ACROSS
NRN ONTARIO AND LAKE SUPERIOR THIS AFTERNOON COMBINED WITH UPR DIV
IN RIGHT ENTRANCE REGION OF ASSOC 100+ KT 3H JET HAVE HELPED SUSTAIN
A COUPLE DIFFERENT BATCHES OF SHRA WHICH HAVE MOVED OVER THE WEST
HALF OF UPPER MI THIS AFTERNOON. UPSLOPE FOG WHICH PLAGUED THE
KEWEENAW INTO THE EARLY AFTERNOON HOURS LOOKS LIKE IT HAS FINALLY
LIFTED PER SFC OBS AND WEB CAMS BUT STRATUS CLOUDS STILL REMAIN. AT
THE SFC...A COUPLE OF SFC TROUGHS EXTEND FM LOW PRES CENTERED NE OF
LAKE SUPERIOR...ONE TROUGH EXTENDS INTO ERN AND SCNTRL UPR MI WHILE
ANOTHER IS STILL SITUATED OVER FAR NRN LAKE SUPERIOR AND ONTARIO.
TONIGHT...EXPECT AREA OF SHOWERS NOW EXTENDING FM IRON COUNTY INTO
WRN MQT COUNTY TO MOVE SLOWLY EAST OVER THE NEXT COUPLE OF HOURS AND
THEN GRADUALLY DISSIPATE THIS EVENING AS 700-650 MB FGEN SLOWLY
WEAKENS. THERE IS A CONCERN THAT A STRONG TO POSSIBLY SVR STORM
COULD FORM OVER THE ERN HALF OF UPPER MI IN THE NEXT FEW HOURS.
PARTIAL SUNSHINE HAS ALLOWED MLCAPES TO BUILD UP TO AROUND 2000
J/KG. THIS ALONG WITH EFFECTIVE SHEAR OF 50-60 KT AND ENHANCED
CONVERGENCE ALONG SFC TROUGH COULD TRIGGER STORMS OVER ERN UPPER MI
LATE AFTERNOON INTO EARLY EVENING. THIS WILL NEED TO BE CLOSELY
MONITORED ON THE EVENING SHIFT.
THE OTHER CONCERN TONIGHT IS THE POTENTIAL FOR MORE FOG TO FORM LATE
EVENING INTO OVERNIGHT HRS AS TEMPS RADIATE THROUGH UPPER 50S/LOWER
60S DEWPOINTS UNDER LIGHT WINDS AND PARTIAL CLEARING. HAVE EXPANDED
MENTION OF PATCHY TO AREAS OF FOG ACROSS THE CWA AND WOULD NOT BE
SURPRISED TO SEE SOME LOCALLY DENSE FOG AT SOME LOCATIONS.
WEDNESDAY...ANOTHER SHORTWAVE NOW DROPPING DOWN FROM NRN
SASKATCHEWAN/NRN MANITOBA WILL HELP PUSH FRONTAL BOUNDARY INTO THE
AREA. SCNTRL AND ERN UPR MI WILL AGAIN HAVE BEST CHC OF AFTERNOON
SHRA/TSRA AS MLCAPES ARE FCST BY MODELS TO INCREASE TO 500-1000
J/KG. WILL INCLUDE HIGHER CHC 40 PCT POPS OVER THIS AREA. WITH WEAK
DOWNSLOPE WRLY FLOW INTO THE BAY OF GREEN BAY...EXPECT THE WARMEST
HIGH TEMPS (LOWER TO MID 80S) OVER MNM COUNTY. ELSEWHERE MAX TEMPS
WILL GENERALLY BE IN THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 408 PM EDT TUE SEP 10 2013
COLD FRONT WILL BE DEPARTING THE CWA AT THE START OF THE LONG TERM
PERIOD...WHILE A POTENT SHORTWAVE DROPS SOUTHEAST ACROSS THE UPPER
GREAT LAKES REGION. THE MAIN PRECIPITATION WITH THE COLD
FRONT WILL BE SLIDING SOUTHEAST OVER THE EASTERN CWA TO START THE
PERIOD. BEHIND THIS...THERE SHOULD BE A QUICK BREAK TO THE
PRECIPITATION BEFORE COLDER AIR AND ABUNDANT LOW LEVEL MOISTURE
SURGES SOUTH ACROSS LAKE SUPERIOR LATE WEDNESDAY NIGHT INTO THURSDAY
ON THE EAST SIDE OF THE HIGH MOVING INTO THE NORTHERN PLAINS.
THUS...WOULD EXPECT A PERIOD OF PARTLY CLOUDY SKIES FOR A TIME
WEDNESDAY NIGHT BEFORE THE 850MB TEMPS FALL TO 0C BETWEEN 18Z
THURSDAY TO 00Z FRIDAY. SINCE LAKE SUPERIOR TEMPS ARE AROUND
12-16C...THIS INCREASING COLD AIR WILL PUSH DELTA T VALUES TOWARDS
FAVORABLE LAKE EFFECT RAIN SHOWERS AND CLOUDS. THE INVERSION HEIGHT
IS RIGHT AROUND 825MB OR 4.5KFT...SO THAT WILL LIMIT THE CLOUD DEPTH
FOR STRONGER SHOWERS...BUT STILL THINK THERE WILL BE ENOUGH AROUND
FOR ISOLATED/SCATTERED MENTION IN THE FAVORED NORTH-NORTHWEST WIND
LOCATIONS. WILL RAMP UP THE POPS THROUGH THE DAY AS THE COLDEST AIR
AND BEST MOISTURE ARRIVES IN THE AFTERNOON AND EARLY EVENING.
IT IS STARTING TO LOOK LIKE THE CLOUDS WILL LINGER LONGER ON
THURSDAY NIGHT...WHICH BRINGS THE LOW FORECAST AND FROST
POTENTIAL INTO QUESTION. OPTED TO TREND TEMPS AND CLOUDS UP SOME
THROUGH THE NIGHT. THE BEST OPPORTUNITY FOR BREAKS IN THE CLOUDS
LOOKS TO BE OVER THE VERY FAR WEST (GOGEBIC/ONTONAGON COUNTIES) AND
WILL KEEP THE COLDEST TEMPERATURES THERE. THIS LONGER LASTING
MOISTURE CALLS FOR THE CLOUDS TO HANG ON INTO AT LEAST FRIDAY
MORNING AND HAVE TRENDED THE SKY FORECAST UP SIGNIFICANTLY FOR THAT
TIME. ALSO DELAYED THE END OF THE SHOWER CHANCES INTO THE MORNING
FOR LOCATIONS FROM MARQUETTE EASTWARD. ALL OF THE MODELS ARE SHOWING
THE MOISTURE DIMINISHING FROM WEST TO EAST DURING THE AFTERNOON AS
THE HIGH MOVES OVER THE CWA. HIGHS ON FRIDAY WILL BE FAIRLY
COOL...WITH HIGHS IN THE MID AND UPPER 50S.
THIS HIGH WILL LEAD TO A VERY CHILLY NIGHT ON FRIDAY NIGHT. SINCE
WINDS WILL BECOME CALM...SKIES WILL BE CLEAR...AND PWATS ARE AROUND
40-45 PERCENT OF NORMAL...EXPECT A GOOD RADIATIONAL COOLING NIGHT.
FORECAST HAS BEEN HITTING THE POTENTIAL FOR FROST ON FRIDAY NIGHT
AND THAT CONTINUES TO SEEM REASONABLE. DID TREND LOWS DOWN A COUPLE
DEGREES OVER THE INTERIOR LOCATIONS AND IT APPEARS LIKE THERE WILL
BE A DECENT OPPORTUNITY FOR FROST IN THAT AREA WITH LOWS IN THE MID
30S. SOME OF THE TRADITIONAL COLD SPOTS OVER THE CENTRAL/EAST MAY
EVEN FALL BELOW FREEZING FOR AWHILE.
THE HIGH WILL SHIFT SOUTHEAST ON SATURDAY AND INCREASING SOUTHERLY
FLOW WILL PUSH TEMPERATURES BACK TOWARDS NORMAL AND AROUND . WITH
10 DEGREES WARMER THAN FRIDAY. THE AREA UNDER A RIDGE ALOFT...EXPECT
A MOSTLY SUNNY DAY ON SATURDAY.
THE NEXT SHORTWAVE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
AREA SATURDAY NIGHT INTO SUNDAY MORNING. THE 12Z MODEL RUNS OF
THE ECMWF/GFS/GEM HAVE COME INTO DECENT AGREEMENT WITH THE
TRACK OF THE SHORTWAVE BRUSHING THE UPPER GREAT LAKES REGION
AND THUS THE TIMING/LOCATION OF THE FRONT AND PRECIPITATION.
SINCE THE MAIN FORCING/MOISTURE LOOKS TO TRACK ACROSS
NORTHEAST LAKE SUPERIOR...HAVE TRENDED POPS DOWN SOMEWHAT AND
TOWARDS SLIGHT CHANCE AND LOW CHANCE POPS. COLD AIR
WILL ONLY BRUSH THE AREA BEHIND THIS FRONT...SO THINK THE POTENTIAL
FOR LAKE ENHANCED CLOUDS/SHOWERS FOR SUNDAY NIGHT INTO MONDAY LOOKS
TO BE LESS LIKELY THAN SHOWN ON YESTERDAY/S RUNS. HIGH PRESSURE
BUILDS IN FOR MONDAY AND MONDAY NIGHT AND SHOULD LEAD TO DRY WEATHER
FOR THE START OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 736 PM EDT TUE SEP 10 2013
VFR CONDITIONS SHOULD CONTINUE THIS EVENING...BUT EXPECT MORE FOG
REDEVELOPING BY LATE EVENING/OVERNIGHT UNDER LIGHT WINDS AND PARTIAL
CLEARING WITH LIFR TO VLIFR EXPECTED AT ALL SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE INTO THIS EVENING AS
DRIER AIR WORKS IN FROM THE NORTH. WEAK HIGH PRESSURE THIS EVENING
WILL BE REPLACED BY A BROAD TROUGH THAT WILL BE EXTENDING SOUTHWARD
FROM NORTHERN ONTARIO LATE TONIGHT THROUGH EARLY WEDNESDAY EVENING.
A LARGE HIGH PRESSURE ENCOMPASSING MUCH OF S CENTRAL CANADA AND THE
N PLAINS WEDNESDAY NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES
AND THE E COAST FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST
WINDS OVER LAKE SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE LATE
WEDNESDAY NIGHT THROUGH EARLY FRIDAY MORNING...WITH N GUSTS OF
20-30KTS CENTERED ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...TITUS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
619 PM EDT MON SEP 9 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 334 PM EDT MON SEP 9 2013
A WARM FRONT MOVED THROUGH WITH SOME HEAVY RAIN MONDAY MORNING.
THE RAIN IS GONE AND WARM AND HUMID WEATHER WILL BE AROUND UNTIL
TUESDAY NIGHT AND WEDNESDAY BEFORE A COLD FRONT USHERS IN SOME
VERY COOL TEMPERATURES FOR THE END OF THE WEEK.
&&
.UPDATE...
ISSUED AT 619 PM EDT MON SEP 9 2013
WE HAVE ISSUED AN UPDATE TO ADD IN A FEW SHOWERS/ISOLATED STORMS
FOR THE NEXT COUPLE OF HOURS UP NORTH FOR OSCEOLA AND CLARE
COUNTIES. A FEW SHOWERS WERE OCCURRING NORTH OF THE CWFA NORTH OF
THE WARM FRONT AND INTERACTING WITH AN OLD REMNANT MCV COMING IN
FROM THE W/NW. IT APPEARS THESE SHOULD MOVE OUT IN THE NEXT COUPLE
OF HOURS...AND ALLOW FOR THE EXPECTED DRY NIGHT OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 334 PM EDT MON SEP 9 2013
FORECAST ISSUES IN THE NEAR TERM ARE POTENTIAL FOR SOME SHOWERS
THIS EVENING...MAX TEMPS ON TUESDAY AND TIMING PRECIP ALONG THE
FRONT TUESDAY NIGHT THROUGH WEDNESDAY.
AS FOR WHAT HAPPENED LAST NIGHT...THE STORMS CERTAINLY
OUTPERFORMED THE FORECAST QPF AS MID LEVEL INSTABILITY COMBINED
WITH STRONG MOISTURE ADVECTION AND ISENTROPIC LIFT NORTH OF THE
SFC WARM FRONT. IT APPEARS THE REMNANTS OF AN MCS HELPED FOCUS THE
CONVECTION AS WELL...WITH RADAR LOOPS SHOWING AN MCV CIRCULATION
MOVING SOUTHEAST ACROSS THE FORECAST AREA CONCURRENT WITH THE DEEP
CONVECTION.
AS FOR LATE THIS AFTERNOON AND EVENING...THE SFC WARM FRONT
WILL BE LIFTING NORTH ACROSS LOWER MICHIGAN AND THE HRRR IS SHOWING
SHOWERS BRUSHING THE NORTHERN FORECAST AREA AS AN MCS MOVES EAST
ACROSS THE UPPER PENINSULA. WILL HAVE TO WATCH THIS. WENT WITH A
DRY FORECAST TONIGHT AS MODEL SOUNDINGS SHOW CAPPING INVERSION AS
WARM AIR CONTINUES TO ADVECT IN AT MID LEVELS.
EXPECT THE CAPPING TO CONTINUE TUESDAY EVEN AS SFC LOW MOVES
ACROSS NORTHERN LOWER MICHIGAN. WENT WITH A DRY FORECAST UP NORTH
WITH THE EXPECTATION THAT RAINS WILL HOLD OFF UNTIL FRONT BEGINS
TO SAG SOUTH TUESDAY NIGHT. SHOWERS AND STORMS CONTINUE TO SPREAD
SLOWLY SOUTH THROUGH WEDNESDAY. THE FRONT SHOULD CLEAR SOUTHERN
ZONES WEDNESDAY EVENING WITH SHOWERS ENDING FROM NORTH TO SOUTH.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 334 PM EDT MON SEP 9 2013
MAIN ITEMS TO FOCUS ON IN THE LONG TERM ARE THE COOL AIR MASS THAT
WILL SETTLE IN ACROSS THE AREA AND THEN THE PCPN CHCS OVER THE
WEEKEND WITH THE NEXT SYSTEM EXPECTED TO MOVE IN ACROSS THE AREA. NO
REAL CHANGES WERE MADE TO THE FCST AS THE LATEST DATA CONTINUES TO
SUPPORT THE GOING FCST.
THE FCST LOOKS LIKE IT SHOULD REMAIN DRY FROM THE THU THROUGH SAT
TIME FRAME. THE MAIN FRONT MOVING THROUGH WED SHOULD BE WELL SOUTH
OF THE AREA BY THU MORNING. IT APPEARS WE WILL SEE A SECONDARY FRONT
MOVING THROUGH ON THU. MOISTURE IS QUITE LIMITED ON THU SO WE DO
NOT EXPECT PCPN WITH THE SECONDARY FRONT.
THE HEART OF THE COLD AIR ALOFT WILL MOVE IN BY FRI MORNING. H850
TEMPS ARE EXPECTED TO BOTTOM OUT AROUND 0 TO 2C. THIS HAS THE
POTENTIAL TO PRODUCE LAKE EFFECT...HOWEVER THE MEAN LOW LEVEL FLOW
WILL BE NNE. THIS SHOULD KEEP LAKE EFFECT WEST AND WELL EAST OF THE
CWFA FROM LAKES MICHIGAN AND HURON RESPECTIVELY. SOME FROST WILL BE
POSSIBLE UP NORTH IN THE NORMALLY COLDER LOCATIONS. TEMPS WILL THEN
MODERATE A BIT FOR SAT AS SHORT WAVE RIDGING ALOFT MOVES IN AND AS
RETURN FLOW BEGINS TO SET UP IN THE LOWER LEVELS.
THE NEXT CHANCE OF RAIN WILL COME IN LATE SAT NIGHT AND DURING THE
DAY ON SUN. A STRONG RIDGE WILL BUILD ACROSS THE ROCKIES BY SUN.
THIS WILL HELP TO DIG A FAIRLY GOOD SHORT WAVE SE INTO THE AREA. NOT
A LOT OF INSTABILITY SHOWN BY THE MODELS FOR STORMS. THERE IS JUST
ENOUGH COMBINED WITH A WELL DEFINED SHORT WAVE TO JUSTIFY THE
MENTION FOR NOW. THIS SHOULD CLEAR OUT BY MON...PROVIDING ANOTHER
COOL DOWN FOR THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 140 PM EDT MON SEP 9 2013
WE EXPECT VFR CONDITIONS TO RULE FOR THE NEXT 24 HOURS AND LIKELY
BEYOND. MAIN ISSUE WILL BE SOME STRONGER WIND EXPECTED TO DEVELOP.
CONVECTION FROM THIS MORNING HAS WEAKENED CONSIDERABLY AND MOVED
WELL EAST OF THE AREA. SKIES ARE CLEARING OUT NICELY AS WE GET
INTO THE MUCH WARMER AIR. SKIES SHOULD REMAIN MAINLY CLEAR THROUGH
TONIGHT AND MOST OF TUE. A DECENT BREEZE EXPECTED TO INCREASE
TONIGHT SHOULD KEEP FOG POTENTIAL LIMITED EVEN WITH THE RECENT RAINFALL.
AS FAR AS THE WINDS ARE CONCERNED...THEY ARE EXPECTED TO INCREASE
THIS EVENING ACROSS THE TERMINALS. WE EXPECT A STEADY 10-12 KNOT
BREEZE EVERYWHERE OVERNIGHT WITH SOME GUSTS POSSIBLE AT KMKG NEAR
THE LAKESHORE. STRONGER WINDS AT AROUND 2K FT AGL WILL PRODUCE
SOME LOW LEVEL WIND SHEAR MAINLY DUE TO SPEED WITH 35-40 KNOTS OUT
OF THE SW. WE FEEL THERE IS NOT ENOUGH OF A DIFFERENCE TO INSERT
IT IN THE FCST...BUT IT WILL BE THERE. SOME WIND GUSTS TO 20 KNOTS
OR SO WILL BE LIKELY ON TUE AS DIURNAL MIXING TAKES PLACE.
&&
.MARINE...
ISSUED AT 334 PM EDT MON SEP 9 2013
WINDS AND WAVES ARE COMING UP AND SCA CONDITIONS EXPECTED TO
PERSIST INTO TUESDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 334 PM EDT MON SEP 9 2013
HEAVY RAIN POTENTIAL IS LOW UNTIL TUESDAY NIGHT WEDNESDAY WHEN A
COLD FRONT MOVES THROUGH.
&&
.CLIMATE...
ISSUED AT 334 PM EDT MON SEP 9 2013
MAX TEMPS ON TUESDAY COULD CHALLENGE RECORDS AT THE THREE PRIMARY
CLIMATE SITES...ESPECIALLY MUSKEGON WHERE THE RECORD IS ONLY 88.
RECORD AT GRAND RAPIDS IS 94 AND LANSING 93.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH TUESDAY AFTERNOON FOR MIZ037-043-
050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LMZ844>849.
&&
$$
UPDATE...NJJ
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...NJJ
HYDROLOGY...OSTUNO
CLIMATE...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 PM EDT MON SEP 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID LEVEL LOW OVER NE
MT. LOW IS WEAKENING/OPENING UP ON WATER VAPOR LOOP/ANALYSIS AND IS
FCST TO MOVE E THROUGH THE NRN PLAINS STATES TONIGHT. ASSOC SFC LOW
NOW OVER SW MN IS IN TURN FCST TO LIFT NE ACROSS THE FCST AREA
TONIGHT WITH APPROACH OF NRN PLAINS SHORTWAVE. STRONG WAA/ISENTROPIC
LIFT AHEAD OF FRONTAL BOUNDARY AS IT LIFTS FM SRN WI TOWARD SCNTRL
UPR MI THIS EVENING WILL PROVIDE FOCUS FOR ANOTHER ROUND OF
CONVECTION TONIGHT WITH THE POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS.
TONIGHT...BIGGEST THING GOING AGAINST SVR WX TONIGHT WILL BE LACK OF
SFC-BASED INSTABILITY FM TODAY DUE TO THICK CLOUDS PERSISTING OVER
THE AREA FM EARLIER MCS OVER THE NRN PLAINS. EVEN SO...COMBINATION
OF STRENGTHING LOW-LVL JET...INCREASING WAA/ISENTROPIC LIFT AND
ADVANCE OF WARM FRONTAL BOUNDARY TOWARD SCNTRL FCST AREA WILL ALLOW
FOR INCREASING ELEVATED INSTABILITY (NAM AND RUC SHOW ELEVATED CAPES
IN EXCESS OF 2000 J/KG THIS EVENING) AND DEEP LAYER SHEAR TO 45-50
KT WHICH COULD BRING POTENTIAL FOR STRONG TO POSSIBLY SVR
STORMS...WITH THE BEST THREAT FOR SVR OVER SCNTRL MI AND SE UPR MI
IN CLOSER PROXIMITY TO ADVANCING WARM FRONT. GIVEN LACK OF SFC-BASED
INSTABILITY...THERE MAY BE MORE OF A THREAT OF ELEVATED STORMS WITH
LARGE HAIL PERHAPS BEING THE BIGGER THREAT FOR OUR AREA. WILL
CONTINUE TO MENTION STRONG TO SEVERE STORMS IN THE HWO WITH THE BEST
THREAT OF HEAVY RAINFALL ACROSS NRN UPR MI AND THE KEWEENAW
PENINSULA. MODEL QPF STILL SUGGESTS THE KEWEENAW PENINSULA AND ERN
UPR MI WILL HAVE BEST CHC FOR HEAVY RAINFALL TONIGHT. LOOK FOR A
GENERAL DIMINISHING TREND IN CONVECTION OVERNIGHT (AFT 06Z) AS
LOW-LVL JET VEERS FM SW TO A MORE WRLY DIRECTION.
DENSE FOG HAS BEEN OBSERVED OVER THE KEWEENAW PENINSULA AND LAKE
SUPERIOR THIS AFTERNOON AND WOULD EXPECT FOG TO CONTINUE INTO THIS
EVENING WITH SHRA MOVING OVER THE AREA AND ONSHORE E-SE FLOW
PERSISTING. EXPECT PATCHY FOG TO MOVE ONSHORE TO NRN ZONES LATE
TONIGHT AS WIND SHIFTS N-NW BEHIND SFC TROUGH.
TUESDAY...THERE COULD BE SOME LINGERING UPSLOPE DZ IN THE MORNING
OVER NRN ZONES AS LOW-LVLS REMAIN MOIST. SOME ISOLD SHRA ARE ALSO
POSSIBLE MAINLY OVER SCNTRL AND ERN SECTIONS OF THE CWA UNTIL
LINGERING SFC BOUNDARY SAGS SE OF THE AREA LATE IN THE DAY.
PERSISTENT CLOUDS OVER THE AREA WILL RESULT IN HIGH TEMPS RANGING
FROM THE 60S NEAR LAKE SUPERIOR IN ONSHORE FLOW TO THE MID 70S
SCNTRL AND EAST ALONG FRONTAL BOUNDARY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 419 PM EDT MON SEP 9 2013
A WEAK HIGH PRESSURE RIDGE WILL SLIDE OVER THE AREA ON TUESDAY
NIGHT BEHIND THE EXITING LOW PRESSURE SYSTEM. WITH THE AREA STILL
UNDER THE RIGHT REAR OF THE UPPER JET...A WEAK SHORTWAVE MOVING
THROUGH...AND SOME LINGERING MOISTURE...OPTED TO LINGER A FEW
ISOLATED SHOWERS NEAR LAKE MICHIGAN FOR THE FIRST PART OF THE
EVENING.
ATTENTION THEN TURNS TO THE SHORTWAVE THAT IS CURRENTLY IN THE
WESTERN PART OF THE NORTHWEST TERRITORIES. THIS SHORTWAVE WILL DIVE
SOUTHEAST TO LAKE WINNIPEG BY 12Z WEDNESDAY AND THEN THROUGH THE
UPPER GREAT LAKES WEDNESDAY NIGHT AND CONTINUE TO INFLUENCE THE
WEATHER INTO THURSDAY. A LOW PRESSURE SYSTEM ASSOCIATED WITH THIS
SHORTWAVE WILL TRACK ACROSS NORTHERN ONTARIO AND SWEEP THE MAIN COLD
FRONT ACROSS THE CWA LATE WEDNESDAY MORNING AND INTO THE AFTERNOON.
A WEAK TROUGH WILL TRY TO SLIDE ACROSS THE AREA LATE TUESDAY
NIGHT...WHICH COULD PRODUCE A FEW SHOWERS. BUT THE BEST CHANCE WILL
BE IN THE AFTERNOON WITH THE MAIN FRONT AND ASSISTANCE FROM DIURNAL
HEATING. THE MAIN INHIBITING FACTOR FOR MORE WIDESPREAD SHOWERS IS
THE SPLOTCHY NATURE OF THE DEEPER MOISTURE IN THE MODELS.
THUS...WILL GO FOR MORE LOW END CHANCES...WITH THE HIGHEST OVER THE
EAST BASED OFF THE TIMING OF THE FRONT WITH PEAK HEATING. DID CAP
THUNDER MENTION AT SLIGHT CHANCES...DUE TO THE WIDE VARIETY OF
MLCAPE VALUES IN THE MODELS (RANGING FROM 200-700 J/KG).
THURSDAY WILL BE COOL AND BREEZY ACROSS THE AREA WITH THE TIGHT
PRESSURE GRADIENT AS HIGH PRESSURE BUILDS INTO THE NORTHERN PLAINS.
850MB TEMPS WILL FALL FROM AROUND 11C ON WEDNESDAY TO 0-2C BY 00Z
THURSDAY. THE COOL TEMPERATURES OVER THE WARM LAKE WATERS WILL
COMBINE WITH THE LOW LEVEL MOISTURE SHOWN ON BOTH ECMWF/GFS FOR
LAKE INDUCED CLOUDS AND PROBABLY A FEW SHOWERS OVER THE LOCATIONS
FAVORED BY NORTH-NORTHWEST WINDS. EXPECT THE STRONGEST WIND GUSTS
TO BE OVER THE EASTERN CWA...WHERE WINDS WILL BE GUSTING TO
30MPH. WITH TEMPERATURES IN THE UPPER 50S AND LOWER 60S...THE
CLOUDS/WINDS/SHOWERS WILL LEAD TO A VERY OCTOBER LIKE DAY FOR MID
SEPTEMBER.
THE HIGH WILL BUILD SOUTHEAST ON THURSDAY NIGHT AND BE CENTERED
OVER THE AREA FOR FRIDAY AFTERNOON AND EVENING. THE DRY AIR
ASSOCIATED WITH THE HIGH WILL DIMINISH THE CLOUDS...BUT ALSO BRING
THE POTENTIAL FOR FROST OVER THE INTERIOR LOCATIONS THURSDAY NIGHT
AND FRIDAY NIGHT. CONFIDENCE IS FAIRLY LOW FOR THURSDAY NIGHT...AS
IT WILL DEPEND ON THE TIMING OF THE EXITING CLOUDS AND ALSO THE
WINDS WEAKENING UP FOR DECENT RADIATIONAL COOLING. THINK THE WESTERN
CWA WILL HAVE THE BEST CHANCE ON THURSDAY NIGHT AND WILL CONTINUE
THE COOLEST TEMPS THERE. THE CENTRAL AND EAST WILL HAVE THE BEST
SHOT FOR FROST ON FRIDAY NIGHT...SINCE THEY WILL BE THE CLOSEST TO
THE HIGH CENTER WITH THE LIGHTER WINDS. OVER THE FAR
WEST...SOUTHERLY RETURN FLOW ON THE BACK SIDE OF THE HIGH ON
FRIDAY NIGHT PRODUCES A LITTLE MORE UNCERTAINTY ON HOW COLD THE
TEMPS WILL GET BEFORE WINDS BEGIN TO PICK UP.
UPPER RIDGE WILL MOVE INTO THE AREA FOR SATURDAY AND BRING
TEMPERATURES BACK UP TOWARDS THE MID-UPPER 60S. THE NEXT SYSTEM
LOOKS TO AFFECT THE AREA ON SATURDAY NIGHT INTO SUNDAY. THIS
SHORTWAVE AND SURFACE LOW LOOK TO TAKE A SIMILAR TRACK TO THE ONE
THIS WEDNESDAY...ALTHOUGH THERE APPEARS TO BE A BETTER OPPORTUNITY
FOR RETURN FLOW TO PROVIDE MORE MOISTURE FOR SHOWERS AS THE FRONT
MOVES THROUGH. INSTABILITY AND MID-LEVEL LAPSE RATES ARE VERY
WEAK...SO HAVE LEFT THE MENTION OF THUNDER OUT OF THE FORECAST.
ONCE AGAIN...HIGH PRESSURE AND COOLER 850MB TEMPS WILL MOVE IN FOR
SUNDAY AFTERNOON INTO MONDAY...BRINGING ANOTHER BELOW NORMAL
TEMPERATURE DAY FOR MONDAY. GFS/ECMWF DO DIFFER ON THE AMOUNT OF
LOW LEVEL MOISTURE PRESENT FOR SUNDAY NIGHT INTO MONDAY...BUT WITH
THE COLD TEMPERATURES ALOFT IT SHOULDN/T TAKE MUCH TO KICK OF LAKE
CLOUDS OR EVEN SOME SHOWERS (AT LEAST FOR SUNDAY NIGHT).
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 140 PM EDT MON SEP 9 2013
WARM/MOIST AIR SURGING INTO THE UPPER GREAT LAKES IN A SE FLOW WILL
RESULT IN GENERALLY IFR TO OCCASIONAL LIFR CIGS AND OCCASIONAL SHRA THRU
THE DAY AT KIWD/KCMX/KSAW. POTENTIAL FOR ADDITIONAL CONVECTION WILL
RETURN THIS EVENING. CONDITIONS AT ALL TERMINALS SHOULD FALL TO IFR
OR LOWER TONIGHT...ESPECIALLY AS WINDS BECOME UPSLOPE AT EACH
TERMINAL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EDT MON SEP 9 2013
LOW PRESSURE OVER NORTHEAST SD WILL LIFT INTO CENTRAL AND ERN UPR MI
TONIGHT AND THEN INTO FAR SE ONTARIO ON TUESDAY. NE WINDS FUNNELING
DOWN THE WRN PORTION OF LAKE SUPERIOR COULD GUST OVER 20 KT THIS
EVENING ON THE BACKSIDE OF THE LOW. A BRIEF RIDGE WILL MOVE OVER
LAKE SUPERIOR TUESDAY AFTERNOON THROUGH TUESDAY NIGHT...OUT AHEAD OF
A WEAK TROUGH EXTENDING FROM NORTHERN ONTARIO DURING THE DAY
WEDNESDAY. LARGE HIGH PRESSURE OVER SOUTH CENTRAL CANADA WEDNESDAY
NIGHT WILL SLOWLY SINK ACROSS GREAT LAKES...WHERE IT WILL REMAIN
FROM THURSDAY NIGHT THROUGH FRIDAY NIGHT. NW WINDS WILL LIKELY GUST
20-30KTS LATE WEDNESDAY NIGHT THROUGH LATE THURSDAY NIGHT AS HIGH
PRESSURE SINKS IN FROM THE NNW. OTHERWISE WITH HIGH PRESSURE
OVERHEAD...LIGHT WINDS LESS THAN 20KTS ARE EXPECTED BY FRIDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
335 PM EDT MON SEP 9 2013
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO/CLIMATE/MARINE
.SYNOPSIS...
ISSUED AT 334 PM EDT MON SEP 9 2013
A WARM FRONT MOVED THROUGH WITH SOME HEAVY RAIN MONDAY MORNING.
THE RAIN IS GONE AND WARM AND HUMID WEATHER WILL BE AROUND UNTIL
TUESDAY NIGHT AND WEDNESDAY BEFORE A COLD FRONT USHERS IN SOME
VERY COOL TEMPERATURES FOR THE END OF THE WEEK.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 334 PM EDT MON SEP 9 2013
FORECAST ISSUES IN THE NEAR TERM ARE POTENTIAL FOR SOME SHOWERS
THIS EVENING...MAX TEMPS ON TUESDAY AND TIMING PRECIP ALONG THE
FRONT TUESDAY NIGHT THROUGH WEDNESDAY.
AS FOR WHAT HAPPENED LAST NIGHT...THE STORMS CERTAINLY
OUTPERFORMED THE FORECAST QPF AS MID LEVEL INSTABILITY COMBINED
WITH STRONG MOISTURE ADVECTION AND ISENTROPIC LIFT NORTH OF THE
SFC WARM FRONT. IT APPEARS THE REMNANTS OF AN MCS HELPED FOCUS THE
CONVECTION AS WELL...WITH RADAR LOOPS SHOWING AN MCV CIRCULATION
MOVING SOUTHEAST ACROSS THE FORECAST AREA CONCURRENT WITH THE DEEP
CONVECTION.
AS FOR LATE THIS AFTERNOON AND EVENING...THE SFC WARM FRONT
WILL BE LIFTING NORTH ACROSS LOWER MICHIGAN AND THE HRRR IS SHOWING
SHOWERS BRUSHING THE NORTHERN FORECAST AREA AS AN MCS MOVES EAST
ACROSS THE UPPER PENINSULA. WILL HAVE TO WATCH THIS. WENT WITH A
DRY FORECAST TONIGHT AS MODEL SOUNDINGS SHOW CAPPING INVERSION AS
WARM AIR CONTINUES TO ADVECT IN AT MID LEVELS.
EXPECT THE CAPPING TO CONTINUE TUESDAY EVEN AS SFC LOW MOVES
ACROSS NORTHERN LOWER MICHIGAN. WENT WITH A DRY FORECAST UP NORTH
WITH THE EXPECTATION THAT RAINS WILL HOLD OFF UNTIL FRONT BEGINS
TO SAG SOUTH TUESDAY NIGHT. SHOWERS AND STORMS CONTINUE TO SPREAD
SLOWLY SOUTH THROUGH WEDNESDAY. THE FRONT SHOULD CLEAR SOUTHERN
ZONES WEDNESDAY EVENING WITH SHOWERS ENDING FROM NORTH TO SOUTH.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 334 PM EDT MON SEP 9 2013
MAIN ITEMS TO FOCUS ON IN THE LONG TERM ARE THE COOL AIR MASS THAT
WILL SETTLE IN ACROSS THE AREA AND THEN THE PCPN CHCS OVER THE
WEEKEND WITH THE NEXT SYSTEM EXPECTED TO MOVE IN ACROSS THE AREA. NO
REAL CHANGES WERE MADE TO THE FCST AS THE LATEST DATA CONTINUES TO
SUPPORT THE GOING FCST.
THE FCST LOOKS LIKE IT SHOULD REMAIN DRY FROM THE THU THROUGH SAT
TIME FRAME. THE MAIN FRONT MOVING THROUGH WED SHOULD BE WELL SOUTH
OF THE AREA BY THU MORNING. IT APPEARS WE WILL SEE A SECONDARY FRONT
MOVING THROUGH ON THU. MOISTURE IS QUITE LIMITED ON THU SO WE DO
NOT EXPECT PCPN WITH THE SECONDARY FRONT.
THE HEART OF THE COLD AIR ALOFT WILL MOVE IN BY FRI MORNING. H850
TEMPS ARE EXPECTED TO BOTTOM OUT AROUND 0 TO 2C. THIS HAS THE
POTENTIAL TO PRODUCE LAKE EFFECT...HOWEVER THE MEAN LOW LEVEL FLOW
WILL BE NNE. THIS SHOULD KEEP LAKE EFFECT WEST AND WELL EAST OF THE
CWFA FROM LAKES MICHIGAN AND HURON RESPECTIVELY. SOME FROST WILL BE
POSSIBLE UP NORTH IN THE NORMALLY COLDER LOCATIONS. TEMPS WILL THEN
MODERATE A BIT FOR SAT AS SHORT WAVE RIDGING ALOFT MOVES IN AND AS
RETURN FLOW BEGINS TO SET UP IN THE LOWER LEVELS.
THE NEXT CHANCE OF RAIN WILL COME IN LATE SAT NIGHT AND DURING THE
DAY ON SUN. A STRONG RIDGE WILL BUILD ACROSS THE ROCKIES BY SUN.
THIS WILL HELP TO DIG A FAIRLY GOOD SHORT WAVE SE INTO THE AREA. NOT
A LOT OF INSTABILITY SHOWN BY THE MODELS FOR STORMS. THERE IS JUST
ENOUGH COMBINED WITH A WELL DEFINED SHORT WAVE TO JUSTIFY THE
MENTION FOR NOW. THIS SHOULD CLEAR OUT BY MON...PROVIDING ANOTHER
COOL DOWN FOR THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 140 PM EDT MON SEP 9 2013
WE EXPECT VFR CONDITIONS TO RULE FOR THE NEXT 24 HOURS AND LIKELY
BEYOND. MAIN ISSUE WILL BE SOME STRONGER WIND EXPECTED TO DEVELOP.
CONVECTION FROM THIS MORNING HAS WEAKENED CONSIDERABLY AND MOVED
WELL EAST OF THE AREA. SKIES ARE CLEARING OUT NICELY AS WE GET
INTO THE MUCH WARMER AIR. SKIES SHOULD REMAIN MAINLY CLEAR THROUGH
TONIGHT AND MOST OF TUE. A DECENT BREEZE EXPECTED TO INCREASE
TONIGHT SHOULD KEEP FOG POTENTIAL LIMITED EVEN WITH THE RECENT RAINFALL.
AS FAR AS THE WINDS ARE CONCERNED...THEY ARE EXPECTED TO INCREASE
THIS EVENING ACROSS THE TERMINALS. WE EXPECT A STEADY 10-12 KNOT
BREEZE EVERYWHERE OVERNIGHT WITH SOME GUSTS POSSIBLE AT KMKG NEAR
THE LAKESHORE. STRONGER WINDS AT AROUND 2K FT AGL WILL PRODUCE
SOME LOW LEVEL WIND SHEAR MAINLY DUE TO SPEED WITH 35-40 KNOTS OUT
OF THE SW. WE FEEL THERE IS NOT ENOUGH OF A DIFFERENCE TO INSERT
IT IN THE FCST...BUT IT WILL BE THERE. SOME WIND GUSTS TO 20 KNOTS
OR SO WILL BE LIKELY ON TUE AS DIURNAL MIXING TAKES PLACE.
&&
.MARINE...
ISSUED AT 334 PM EDT MON SEP 9 2013
WINDS AND WAVES ARE COMING UP AND SCA CONDITIONS EXPECTED TO
PERSIST INTO TUESDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 334 PM EDT MON SEP 9 2013
HEAVY RAIN POTENTIAL IS LOW UNTIL TUESDAY NIGHT WEDNESDAY WHEN A
COLD FRONT MOVES THROUGH.
&&
.CLIMATE...
ISSUED AT 334 PM EDT MON SEP 9 2013
MAX TEMPS ON TUESDAY COULD CHALLENGE RECORDS AT THE THREE PRIMARY
CLIMATE SITES...ESPECIALLY MUSKEGON WHERE THE RECORD IS ONLY 88.
RECORD AT GRAND RAPIDS IS 94 AND LANSING 93.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT THROUGH TUESDAY AFTERNOON FOR MIZ037-043-
050-056-064-071.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EDT TUESDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...NJJ
HYDROLOGY...OSTUNO
CLIMATE...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
159 PM EDT MON SEP 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EDT MON SEP 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID LEVEL LOW OVER MT.
LOW IS WEAKENING/OPENING UP AND FINALLY MOVING E AFTER BEING OVER
THE PACIFIC NW DURING THE LAST FEW DAYS. AHEAD OF THIS FEATURE...
SHRA/TSRA OVER THE WRN DAKOTAS LAST EVENING HAVE ORGANIZED INTO A
WELL DEVELOPED MCS WHICH IS NOW MOVING ACROSS THE ERN DAKOTAS. PER
LATEST RUC/SPC MESOANALYSIS...40-50KT LOW-LEVEL JET IS ADVECTING
MUCAPE OF 3000J/KG INTO THE COMPLEX...HELPING TO MAINTAIN IT. MCS IS
MOVING AROUND A WEAKENING RIDGE WHICH REMAINS OVER THE CNTRL CONUS.
CLOSER TO HOME...SOME -SHRA...MOSTLY JUST SPRINKLES...HAVE PUSHED
ACROSS THE WRN AND SRN FCST AREA OVERNIGHT IN A GENERALLY WEAK
ISENTROPIC ASCENT REGIME. OVER THE LAST COUPLE OF HRS...SOUTHERLY
FLOW UP LAKE MICHIGAN HAS INCREASED ENOUGH TO BEGIN PUSHING HIGHER
DWPT MARINE LAYER AIR INTO THE ERN FCST AREA. WITH TEMPS IN THE
INTERIOR IN THE 40S/LWR 50S...MAY SEE SOME FOG/STRATUS DEVELOP THERE
IN THE NEXT COUPLE OF HRS.
INITIALLY...WILL CARRY ISOLD/SCT SHRA ACROSS THE FCST AREA FOR THE
NEXT SEVERAL HRS IN ONGOING MODEST WAA/ISENTROPIC ASCENT. THEN...
SHORT TERM FCST WILL REVOLVE AROUND PROGRESS OF THE SYSTEM OVER MT
AND MORE IMPORTANTLY THE MCS OVER THE DAKOTAS. AS ALWAYS...PINNING
DOWN CONVECTION EVEN IN THE SHORT TERM IS A CHALLENGE. TODAYS FCST
IS ESPECIALLY CHALLENGING GIVEN THE WELL-DEVELOPED MCS NOW OVER THE
ERN DAKOTAS AS IT SEEMS QUITE LIKELY THAT AN MCV WILL SPIN UP AND
MAY BECOME THE MAIN FEATURE TO KEY ON FOR THE PCPN FCST HERE. TRIED
TO INCORPORATE THE IDEA OF THE MCS HOLDING TOGETHER TO SOME EXTENT.
AS IT LIFTS ENE...MAY SEE AN ARC OF SHRA/TSRA SWING ACROSS
ESPECIALLY NW UPPER MI LATER THIS MORNING IN ZONE OF ENHANCED
WAA/ISENTROPIC ASCENT. WHAT TRANSPIRES AFTERWARDS IS UNCERTAIN. IF
MCV TRACKS N OF THE AREA...THE MAIN CLUSTER OF SHRA/TSRA WILL PASS
MOSTLY N OF UPPER MI TODAY WITH TAIL OF WAVE POSSIBLY GENERATING A
BAND OF SVR STORMS LATE AFTN/EVENING AS MLCAPE UPWARDS OF 2000J/KG
BUILDS NE INTO UPPER MI IN THE PRESENCE OF 40-50KT DEEP LAYER SHEAR.
IF MCV PASSES ACROSS UPPER MI...THEN MOST AREAS WILL SEE A FEW HRS
OF SHRA/TSRA THIS AFTN...AND MAIN SVR THREAT COULD BE SHUNTED S FOR
THE LATE AFTN/EVENING. BASED ON RADAR TRENDS...IT APPEARS THE FORMER
IDEA MAY BE THE MORE LIKELY SCENARIO. DEPENDING ON HOW FAR N WARM
SECTOR CAPPED AIR MASS ADVECTS TODAY...SRN FCST AREA MAY SEE
LITTLE/NO CONVECTION AFTER INITIAL POSSIBLE SHRA/TSRA IN
AFORMENTIONED ZONE OF ENHANCED WAA/ISENTROPIC ASCENT PASSES LATER
THIS MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM EDT MON SEP 9 2013
TUESDAY MORNING WILL MARK THE BEGINNING OF A COOLER AND GENERALLY
DRIER TREND THAT WILL REMAIN THROUGH THE REST OF THE FCST PERIOD.
850MB TEMPS AT DAYBREAK TUESDAY SHOULD BE 14-19C...WHICH WILL NOT BE
SEEN AGAIN UNTIL NEXT TUESDAY AT THE EARLIEST.
THE SFC LOW WILL BE EXITING/SLOWLY SINKING TO OUR SE ON TUESDAY...AS
A RIDGE BRIEFLY SLIDES IN. WHILE THERE WILL BE A PERIOD OF DRY
WEATHER...IT WILL BE SHORT LIVED...AS A SERIES OF SHORTWAVES WILL
KEEP IMPACTING THE UPPER GREAT LAKES THROUGH THE DAY THURSDAY.
HIGH PRESSURE WILL BUILD IN AT THE SFC AND ALOFT THURSDAY NIGHT. THE
COLDEST AIR WILL LIKELY BE OVERHEAD THURSDAY NIGHT INTO FRIDAY
MORNING...WITH BOTH THE GFS AND ECMWF INDICATING 850MB TEMPS BETWEEN
0 AND -2C FROM 00Z-12Z FRIDAY ON NNW-NE WINDS OFF LAKE SUPERIOR.
WHILE THERE WILL BE SOME DRYING THURSDAY NIGHT WITH HIGH PRESSURE
ROLLING IN...DIMINISHING 15-20KTS WINDS OFF LAKE SUPERIOR WILL HELP
KEEP LOW LEVEL MOISTURE STUCK ACROSS N UPPER MI INTO FRIDAY MORNING
AS A STRENGTHENING INVERSION TAKES HOLD. FRIDAY MORNING TEMPERATURES
ARE TRICKY. THE 09/00Z RUN OF THE GFS WARMED 850MB TEMPS 2C ON
AVERAGE...WHICH IS APPROX 3-4C WARMER THAN THE 09/12Z ECMWF.
AS THE SFC HIGH EXITS FRIDAY AFTERNOON/EVENING...SLIGHTLY WARMER AIR
WILL BE ABLE TO SWING IN ON W-SW WINDS. THERE WILL STILL BE THE
POTENTIAL FOR PATCHY FROST...BUT MOST LIKELY OVER THE INLAND E
LOCATIONS THAT ARE STILL UNDER THE LINGER INFLUENCE OF THE EXITING
HIGH. WHILE 80 DEGREE TEMPS WILL NOT RETURN...50 DEGREE READING ON
FRIDAY WILL RISE INTO THE MID 60S FOR THE UPCOMING WEEKEND. THE
WARMER TEMPERATURES WILL BE ACCOMPANIED BY A CHANCE OF SHOWERS TO
WRAP UP THE WEEKEND. WILL KEEP THE MENTION OF TS OUT FOR SUNDAY...AS
THE BEST POTENTIAL SHOULD REMAIN WELL TO OUR SW...CLOSER TO THE SFC
LOW ACROSS THE CENTRAL PLAINS WHERE MUCH WARMER AIR WILL RESIDE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 140 PM EDT MON SEP 9 2013
WARM/MOIST AIR SURGING INTO THE UPPER GREAT LAKES IN A SE FLOW WILL
RESULT IN GENERALLY IFR TO OCCASIONAL LIFR CIGS AND OCCASIONAL SHRA THRU
THE DAY AT KIWD/KCMX/KSAW. POTENTIAL FOR ADDITIONAL CONVECTION WILL
RETURN THIS EVENING. CONDITIONS AT ALL TERMINALS SHOULD FALL TO IFR
OR LOWER TONIGHT...ESPECIALLY AS WINDS BECOME UPSLOPE AT EACH
TERMINAL. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT MON SEP 9 2013
LOW PRESSURE OVER SD WILL PUSH THE EXITING RIDGE ACROSS LAKE
SUPERIOR EASTWARD TODAY. FUNNELING NE WINDS WILL GUST TO 20-25KTS
OVER FAR W LAKE SUPERIOR THIS AFTERNOON AND EVENING. EXPECT THE LOW
TO CROSS S LAKE SUPERIOR OVERNIGHT...AND PUSH INTO FAR SE ONTARIO ON
TUESDAY. A BRIEF RIDGE WILL MOVE OVER LAKE SUPERIOR TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT...OUT AHEAD OF A WEAK TROUGH
EXTENDING FROM NORTHERN ONTARIO DURING THE DAY WEDNESDAY. LARGE HIGH
PRESSURE OVER SOUTH CENTRAL CANADA WEDNESDAY NIGHT WILL SLOWLY SINK
ACROSS GREAT LAKES...WHERE IT WILL REMAIN FROM THURSDAY NIGHT
THROUGH FRIDAY NIGHT. NW WINDS WILL LIKELY GUST 20-30KTS LATE
WEDNESDAY NIGHT THROUGH LATE THURSDAY NIGHT AS HIGH PRESSURE SINKS
IN FROM THE NNW. OTHERWISE WITH HIGH PRESSURE OVERHEAD...LIGHT WINDS
LESS THAN 20KTS ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
749 AM EDT MON SEP 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EDT MON SEP 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID LEVEL LOW OVER MT.
LOW IS WEAKENING/OPENING UP AND FINALLY MOVING E AFTER BEING OVER
THE PACIFIC NW DURING THE LAST FEW DAYS. AHEAD OF THIS FEATURE...
SHRA/TSRA OVER THE WRN DAKOTAS LAST EVENING HAVE ORGANIZED INTO A
WELL DEVELOPED MCS WHICH IS NOW MOVING ACROSS THE ERN DAKOTAS. PER
LATEST RUC/SPC MESOANALYSIS...40-50KT LOW-LEVEL JET IS ADVECTING
MUCAPE OF 3000J/KG INTO THE COMPLEX...HELPING TO MAINTAIN IT. MCS IS
MOVING AROUND A WEAKENING RIDGE WHICH REMAINS OVER THE CNTRL CONUS.
CLOSER TO HOME...SOME -SHRA...MOSTLY JUST SPRINKLES...HAVE PUSHED
ACROSS THE WRN AND SRN FCST AREA OVERNIGHT IN A GENERALLY WEAK
ISENTROPIC ASCENT REGIME. OVER THE LAST COUPLE OF HRS...SOUTHERLY
FLOW UP LAKE MICHIGAN HAS INCREASED ENOUGH TO BEGIN PUSHING HIGHER
DWPT MARINE LAYER AIR INTO THE ERN FCST AREA. WITH TEMPS IN THE
INTERIOR IN THE 40S/LWR 50S...MAY SEE SOME FOG/STRATUS DEVELOP THERE
IN THE NEXT COUPLE OF HRS.
INITIALLY...WILL CARRY ISOLD/SCT SHRA ACROSS THE FCST AREA FOR THE
NEXT SEVERAL HRS IN ONGOING MODEST WAA/ISENTROPIC ASCENT. THEN...
SHORT TERM FCST WILL REVOLVE AROUND PROGRESS OF THE SYSTEM OVER MT
AND MORE IMPORTANTLY THE MCS OVER THE DAKOTAS. AS ALWAYS...PINNING
DOWN CONVECTION EVEN IN THE SHORT TERM IS A CHALLENGE. TODAYS FCST
IS ESPECIALLY CHALLENGING GIVEN THE WELL-DEVELOPED MCS NOW OVER THE
ERN DAKOTAS AS IT SEEMS QUITE LIKELY THAT AN MCV WILL SPIN UP AND
MAY BECOME THE MAIN FEATURE TO KEY ON FOR THE PCPN FCST HERE. TRIED
TO INCORPORATE THE IDEA OF THE MCS HOLDING TOGETHER TO SOME EXTENT.
AS IT LIFTS ENE...MAY SEE AN ARC OF SHRA/TSRA SWING ACROSS
ESPECIALLY NW UPPER MI LATER THIS MORNING IN ZONE OF ENHANCED
WAA/ISENTROPIC ASCENT. WHAT TRANSPIRES AFTERWARDS IS UNCERTAIN. IF
MCV TRACKS N OF THE AREA...THE MAIN CLUSTER OF SHRA/TSRA WILL PASS
MOSTLY N OF UPPER MI TODAY WITH TAIL OF WAVE POSSIBLY GENERATING A
BAND OF SVR STORMS LATE AFTN/EVENING AS MLCAPE UPWARDS OF 2000J/KG
BUILDS NE INTO UPPER MI IN THE PRESENCE OF 40-50KT DEEP LAYER SHEAR.
IF MCV PASSES ACROSS UPPER MI...THEN MOST AREAS WILL SEE A FEW HRS
OF SHRA/TSRA THIS AFTN...AND MAIN SVR THREAT COULD BE SHUNTED S FOR
THE LATE AFTN/EVENING. BASED ON RADAR TRENDS...IT APPEARS THE FORMER
IDEA MAY BE THE MORE LIKELY SCENARIO. DEPENDING ON HOW FAR N WARM
SECTOR CAPPED AIR MASS ADVECTS TODAY...SRN FCST AREA MAY SEE
LITTLE/NO CONVECTION AFTER INITIAL POSSIBLE SHRA/TSRA IN
AFORMENTIONED ZONE OF ENHANCED WAA/ISENTROPIC ASCENT PASSES LATER
THIS MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM EDT MON SEP 9 2013
TUESDAY MORNING WILL MARK THE BEGINNING OF A COOLER AND GENERALLY
DRIER TREND THAT WILL REMAIN THROUGH THE REST OF THE FCST PERIOD.
850MB TEMPS AT DAYBREAK TUESDAY SHOULD BE 14-19C...WHICH WILL NOT BE
SEEN AGAIN UNTIL NEXT TUESDAY AT THE EARLIEST.
THE SFC LOW WILL BE EXITING/SLOWLY SINKING TO OUR SE ON TUESDAY...AS
A RIDGE BRIEFLY SLIDES IN. WHILE THERE WILL BE A PERIOD OF DRY
WEATHER...IT WILL BE SHORT LIVED...AS A SERIES OF SHORTWAVES WILL
KEEP IMPACTING THE UPPER GREAT LAKES THROUGH THE DAY THURSDAY.
HIGH PRESSURE WILL BUILD IN AT THE SFC AND ALOFT THURSDAY NIGHT. THE
COLDEST AIR WILL LIKELY BE OVERHEAD THURSDAY NIGHT INTO FRIDAY
MORNING...WITH BOTH THE GFS AND ECMWF INDICATING 850MB TEMPS BETWEEN
0 AND -2C FROM 00Z-12Z FRIDAY ON NNW-NE WINDS OFF LAKE SUPERIOR.
WHILE THERE WILL BE SOME DRYING THURSDAY NIGHT WITH HIGH PRESSURE
ROLLING IN...DIMINISHING 15-20KTS WINDS OFF LAKE SUPERIOR WILL HELP
KEEP LOW LEVEL MOISTURE STUCK ACROSS N UPPER MI INTO FRIDAY MORNING
AS A STRENGTHENING INVERSION TAKES HOLD. FRIDAY MORNING TEMPERATURES
ARE TRICKY. THE 09/00Z RUN OF THE GFS WARMED 850MB TEMPS 2C ON
AVERAGE...WHICH IS APPROX 3-4C WARMER THAN THE 09/12Z ECMWF.
AS THE SFC HIGH EXITS FRIDAY AFTERNOON/EVENING...SLIGHTLY WARMER AIR
WILL BE ABLE TO SWING IN ON W-SW WINDS. THERE WILL STILL BE THE
POTENTIAL FOR PATCHY FROST...BUT MOST LIKELY OVER THE INLAND E
LOCATIONS THAT ARE STILL UNDER THE LINGER INFLUENCE OF THE EXITING
HIGH. WHILE 80 DEGREE TEMPS WILL NOT RETURN...50 DEGREE READING ON
FRIDAY WILL RISE INTO THE MID 60S FOR THE UPCOMING WEEKEND. THE
WARMER TEMPERATURES WILL BE ACCOMPANIED BY A CHANCE OF SHOWERS TO
WRAP UP THE WEEKEND. WILL KEEP THE MENTION OF TS OUT FOR SUNDAY...AS
THE BEST POTENTIAL SHOULD REMAIN WELL TO OUR SW...CLOSER TO THE SFC
LOW ACROSS THE CENTRAL PLAINS WHERE MUCH WARMER AIR WILL RESIDE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 749 AM EDT MON SEP 9 2013
WARM/MOIST AIR SURGING N INTO THE UPPER GREAT LAKES WILL RESULT IN
GENERALLY MVFR CIGS THRU THE DAY AT KIWD/KCMX/KSAW. CONVECTIVE
COMPLEX RACING ACROSS MN SHOULD HOLD TOGETHER SUFFICIENTLY TO BRING
2-3HRS OF SHRA/IFR CONDITIONS TO KIWD LATER THIS MORNING AND TO
KCMX/KSAW THIS AFTN. OCCURRENCE OF TS AT ANY OF THE TERMINALS IS
SOMEWHAT UNCERTAIN AS CONVECTION BEGINS TO OUTRUN INSTABILITY TO
SOME DEGREE. FOR NOW...INCLUDED VCTS. AFTER INITIAL SHRA COMPLEX
PASSES...POTENTIAL FOR ADDITIONAL CONVECTION WILL RETURN THIS
EVENING. CONDITIONS AT ALL TERMINALS SHOULD FALL TO IFR OR LOWER
TONIGHT...ESPECIALLY AS WINDS BECOME UPSLOPING AT EACH TERMINAL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT MON SEP 9 2013
LOW PRESSURE OVER SD WILL PUSH THE EXITING RIDGE ACROSS LAKE
SUPERIOR EASTWARD TODAY. FUNNELING NE WINDS WILL GUST TO 20-25KTS
OVER FAR W LAKE SUPERIOR THIS AFTERNOON AND EVENING. EXPECT THE LOW
TO CROSS S LAKE SUPERIOR OVERNIGHT...AND PUSH INTO FAR SE ONTARIO ON
TUESDAY. A BRIEF RIDGE WILL MOVE OVER LAKE SUPERIOR TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT...OUT AHEAD OF A WEAK TROUGH
EXTENDING FROM NORTHERN ONTARIO DURING THE DAY WEDNESDAY. LARGE HIGH
PRESSURE OVER SOUTH CENTRAL CANADA WEDNESDAY NIGHT WILL SLOWLY SINK
ACROSS GREAT LAKES...WHERE IT WILL REMAIN FROM THURSDAY NIGHT
THROUGH FRIDAY NIGHT. NW WINDS WILL LIKELY GUST 20-30KTS LATE
WEDNESDAY NIGHT THROUGH LATE THURSDAY NIGHT AS HIGH PRESSURE SINKS
IN FROM THE NNW. OTHERWISE WITH HIGH PRESSURE OVERHEAD...LIGHT WINDS
LESS THAN 20KTS ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
536 AM EDT MON SEP 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EDT MON SEP 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A MID LEVEL LOW OVER MT.
LOW IS WEAKENING/OPENING UP AND FINALLY MOVING E AFTER BEING OVER
THE PACIFIC NW DURING THE LAST FEW DAYS. AHEAD OF THIS FEATURE...
SHRA/TSRA OVER THE WRN DAKOTAS LAST EVENING HAVE ORGANIZED INTO A
WELL DEVELOPED MCS WHICH IS NOW MOVING ACROSS THE ERN DAKOTAS. PER
LATEST RUC/SPC MESOANALYSIS...40-50KT LOW-LEVEL JET IS ADVECTING
MUCAPE OF 3000J/KG INTO THE COMPLEX...HELPING TO MAINTAIN IT. MCS IS
MOVING AROUND A WEAKENING RIDGE WHICH REMAINS OVER THE CNTRL CONUS.
CLOSER TO HOME...SOME -SHRA...MOSTLY JUST SPRINKLES...HAVE PUSHED
ACROSS THE WRN AND SRN FCST AREA OVERNIGHT IN A GENERALLY WEAK
ISENTROPIC ASCENT REGIME. OVER THE LAST COUPLE OF HRS...SOUTHERLY
FLOW UP LAKE MICHIGAN HAS INCREASED ENOUGH TO BEGIN PUSHING HIGHER
DWPT MARINE LAYER AIR INTO THE ERN FCST AREA. WITH TEMPS IN THE
INTERIOR IN THE 40S/LWR 50S...MAY SEE SOME FOG/STRATUS DEVELOP THERE
IN THE NEXT COUPLE OF HRS.
INITIALLY...WILL CARRY ISOLD/SCT SHRA ACROSS THE FCST AREA FOR THE
NEXT SEVERAL HRS IN ONGOING MODEST WAA/ISENTROPIC ASCENT. THEN...
SHORT TERM FCST WILL REVOLVE AROUND PROGRESS OF THE SYSTEM OVER MT
AND MORE IMPORTANTLY THE MCS OVER THE DAKOTAS. AS ALWAYS...PINNING
DOWN CONVECTION EVEN IN THE SHORT TERM IS A CHALLENGE. TODAYS FCST
IS ESPECIALLY CHALLENGING GIVEN THE WELL-DEVELOPED MCS NOW OVER THE
ERN DAKOTAS AS IT SEEMS QUITE LIKELY THAT AN MCV WILL SPIN UP AND
MAY BECOME THE MAIN FEATURE TO KEY ON FOR THE PCPN FCST HERE. TRIED
TO INCORPORATE THE IDEA OF THE MCS HOLDING TOGETHER TO SOME EXTENT.
AS IT LIFTS ENE...MAY SEE AN ARC OF SHRA/TSRA SWING ACROSS
ESPECIALLY NW UPPER MI LATER THIS MORNING IN ZONE OF ENHANCED
WAA/ISENTROPIC ASCENT. WHAT TRANSPIRES AFTERWARDS IS UNCERTAIN. IF
MCV TRACKS N OF THE AREA...THE MAIN CLUSTER OF SHRA/TSRA WILL PASS
MOSTLY N OF UPPER MI TODAY WITH TAIL OF WAVE POSSIBLY GENERATING A
BAND OF SVR STORMS LATE AFTN/EVENING AS MLCAPE UPWARDS OF 2000J/KG
BUILDS NE INTO UPPER MI IN THE PRESENCE OF 40-50KT DEEP LAYER SHEAR.
IF MCV PASSES ACROSS UPPER MI...THEN MOST AREAS WILL SEE A FEW HRS
OF SHRA/TSRA THIS AFTN...AND MAIN SVR THREAT COULD BE SHUNTED S FOR
THE LATE AFTN/EVENING. BASED ON RADAR TRENDS...IT APPEARS THE FORMER
IDEA MAY BE THE MORE LIKELY SCENARIO. DEPENDING ON HOW FAR N WARM
SECTOR CAPPED AIR MASS ADVECTS TODAY...SRN FCST AREA MAY SEE
LITTLE/NO CONVECTION AFTER INITIAL POSSIBLE SHRA/TSRA IN
AFORMENTIONED ZONE OF ENHANCED WAA/ISENTROPIC ASCENT PASSES LATER
THIS MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 412 AM EDT MON SEP 9 2013
TUESDAY MORNING WILL MARK THE BEGINNING OF A COOLER AND GENERALLY
DRIER TREND THAT WILL REMAIN THROUGH THE REST OF THE FCST PERIOD.
850MB TEMPS AT DAYBREAK TUESDAY SHOULD BE 14-19C...WHICH WILL NOT BE
SEEN AGAIN UNTIL NEXT TUESDAY AT THE EARLIEST.
THE SFC LOW WILL BE EXITING/SLOWLY SINKING TO OUR SE ON TUESDAY...AS
A RIDGE BRIEFLY SLIDES IN. WHILE THERE WILL BE A PERIOD OF DRY
WEATHER...IT WILL BE SHORT LIVED...AS A SERIES OF SHORTWAVES WILL
KEEP IMPACTING THE UPPER GREAT LAKES THROUGH THE DAY THURSDAY.
HIGH PRESSURE WILL BUILD IN AT THE SFC AND ALOFT THURSDAY NIGHT. THE
COLDEST AIR WILL LIKELY BE OVERHEAD THURSDAY NIGHT INTO FRIDAY
MORNING...WITH BOTH THE GFS AND ECMWF INDICATING 850MB TEMPS BETWEEN
0 AND -2C FROM 00Z-12Z FRIDAY ON NNW-NE WINDS OFF LAKE SUPERIOR.
WHILE THERE WILL BE SOME DRYING THURSDAY NIGHT WITH HIGH PRESSURE
ROLLING IN...DIMINISHING 15-20KTS WINDS OFF LAKE SUPERIOR WILL HELP
KEEP LOW LEVEL MOISTURE STUCK ACROSS N UPPER MI INTO FRIDAY MORNING
AS A STRENGTHENING INVERSION TAKES HOLD. FRIDAY MORNING TEMPERATURES
ARE TRICKY. THE 09/00Z RUN OF THE GFS WARMED 850MB TEMPS 2C ON
AVERAGE...WHICH IS APPROX 3-4C WARMER THAN THE 09/12Z ECMWF.
AS THE SFC HIGH EXITS FRIDAY AFTERNOON/EVENING...SLIGHTLY WARMER AIR
WILL BE ABLE TO SWING IN ON W-SW WINDS. THERE WILL STILL BE THE
POTENTIAL FOR PATCHY FROST...BUT MOST LIKELY OVER THE INLAND E
LOCATIONS THAT ARE STILL UNDER THE LINGER INFLUENCE OF THE EXITING
HIGH. WHILE 80 DEGREE TEMPS WILL NOT RETURN...50 DEGREE READING ON
FRIDAY WILL RISE INTO THE MID 60S FOR THE UPCOMING WEEKEND. THE
WARMER TEMPERATURES WILL BE ACCOMPANIED BY A CHANCE OF SHOWERS TO
WRAP UP THE WEEKEND. WILL KEEP THE MENTION OF TS OUT FOR SUNDAY...AS
THE BEST POTENTIAL SHOULD REMAIN WELL TO OUR SW...CLOSER TO THE SFC
LOW ACROSS THE CENTRAL PLAINS WHERE MUCH WARMER AIR WILL RESIDE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 121 AM EDT MON SEP 9 2013
WITH INCREASING SOUTHERLY WINDS OVERNIGHT INTO THE MORNING...EXPECT
LOW LEVEL MOISTURE OVER WISCONSIN TO BE DRAWN INTO UPPER MICHIGAN
AND MVFR CIGS TO DEVELOP AT CMX/SAW. EVEN WITH DOWNSLOPING FLOW INTO
IWD...MVFR AND POSSIBLY IFR CIGS ARE ALSO EXPECTED.
WHILE SOME LIGHT SHOWERS OR SPRINKLES ARE POSSIBLE OVERNIGHT...
THE BEST OPPORTUNITY FOR SHOWERS IS EXPECTED FROM LATE MORNING INTO
THE EARLY AFTERNOON AS A WARM FRONT LIFTS THROUGH THE AREA TODAY.
CONFIDENCE ON TIMING/LOCATION IS ONLY MODERATE BUT PCPN SHOULD BE
WIDEPSREAD ENOUGH TO MENTION SHRA. POTENTIAL FOR TSRA IS LESS CERTAIN
AND WAS NOT INCLUDED AT THIS TIME.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 412 AM EDT MON SEP 9 2013
LOW PRESSURE OVER SD WILL PUSH THE EXITING RIDGE ACROSS LAKE
SUPERIOR EASTWARD TODAY. FUNNELING NE WINDS WILL GUST TO 20-25KTS
OVER FAR W LAKE SUPERIOR THIS AFTERNOON AND EVENING. EXPECT THE LOW
TO CROSS S LAKE SUPERIOR OVERNIGHT...AND PUSH INTO FAR SE ONTARIO ON
TUESDAY. A BRIEF RIDGE WILL MOVE OVER LAKE SUPERIOR TUESDAY
AFTERNOON THROUGH TUESDAY NIGHT...OUT AHEAD OF A WEAK TROUGH
EXTENDING FROM NORTHERN ONTARIO DURING THE DAY WEDNESDAY. LARGE HIGH
PRESSURE OVER SOUTH CENTRAL CANADA WEDNESDAY NIGHT WILL SLOWLY SINK
ACROSS GREAT LAKES...WHERE IT WILL REMAIN FROM THURSDAY NIGHT
THROUGH FRIDAY NIGHT. NW WINDS WILL LIKELY GUST 20-30KTS LATE
WEDNESDAY NIGHT THROUGH LATE THURSDAY NIGHT AS HIGH PRESSURE SINKS
IN FROM THE NNW. OTHERWISE WITH HIGH PRESSURE OVERHEAD...LIGHT WINDS
LESS THAN 20KTS ARE EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...JLB
MARINE...KF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1209 PM CDT Mon Sep 9 2013
.UPDATE...
Issued at 603 AM CDT MON SEP 9 2013
As noted in the 352 am discussion below an accas field has quickly
formed over the eastern portion of the CWA with widely scattered
elevated convection now being detected by radar. Have updated the
zones/grids to reflect this. Activity is expected to be short-lived
and dissipate by late morning.
&&
.SHORT TERM...(Today through Tuesday)
Issued at 352 AM CDT MON SEP 9 2013
The unseasonably hot conditions will continue today with near record
heat in parts of northern and west central MO. While H8 and 925mb
temperatures are progged to be 1-2C lower than Sunday when triple
digit readings were reached in the KC Metro, mixing will be better
and deeper due to increasing southwest winds. The net effect will be
afternoon temperatures topping out in the middle to upper 90s. If
there is any silver lining to today`s heat it`s the expectation of
lower humidity levels due to this better mixing.
The large anticyclone aloft will be nearly overhead and with its hot
mid level temperatures will suppress most cloud clover let alone any
convective development. However, there is one caveat to this
scenario and it revolves around a weak surface trough extending from
near OMA southeast through central MO. Some of the very short range
models like the RAP and HRRR are hinting at some elevated convection
near this boundary +/- 2-3 hours centered around 12Z. While the
models have been overly generous with qpf the last couple days with
the boundaries that have migrated into the CWA the latest satellite
imagery shows patches of apparently mid clouds forming from far east
central KS to central MO. Will need to monitor radar/satellite for
any development as the current forecast is dry.
Tuesday: more of the same although temperatures look like they will
be a few degrees cooler as the pool of hot air shifts northward.
Nonetheless, temperatures will remain a good 10F above average.
Lacking any boundary and with nearly non-existent moisture under a
strong cap will go with zero PoPs.
Tuesday night: A cold front from southern NE through WI will sag
slowly southward and possibly reach far northwest MO by Wednesday
morning. Models are becoming more reluctant to generate qpf over the
CWA as any convection which forms during this period will likely be
post-frontal. Have confined PoPs to far northwest MO and left rest
of CWA dry.
.LONG TERM...(Wednesday through Sunday)
Issued at 352 AM CDT MON SEP 9 2013
A rather weak front is expected to sink into northern Missouri by
Wednesday morning, but with limited precipitation accompanying it.
A narrow corridor of low level moisture will stretch across southern
Nebraska eastward into central Illinois into Thursday. Depending on
cloud cover, temperatures may again climb into the lower or even
middle 90s Wednesday afternoon and while low, a few thunderstorms
may develop in the unstable airmass south of the boundary.
Slightly higher PoPs are focused Wednesday night into Thursday as
the low-level baroclinic zone shifts southward. However, the LLJ
will back through the night into NW Kansas and SW Nebraska likely
forcing higher precipitation chances well west of the local area.
A secondary cold front will sweep into the area Thursday night,
allowing cool and dry air to push southwest. Temperatures heading
into the weekend will find themselves near the seasonal normals in
the upper 70s to lower 80s. An upper low crossing the Rockies over
the weekend will allow winds to turn back southwesterly on Saturday,
before another front moves into the area Sunday/Monday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1206 PM CDT MON SEP 9 2013
VFR conditions will persist through the forecast period, with mainly
clear skies and southwest winds. Wind speeds will increase over the
next hour or so and remain sustained at around 15 kts this afternoon,
with occasional gusts over 20 kts. Speeds will decrease a bit this
evening, but should stay above 5 kts overnight.
&&
.FIRE WEATHER...
Issued at 352 AM CDT MON SEP 9 2013
There is an elevated fire danger threat this afternoon across
northern and west central MO as well as extreme east central KS. The
heat of the past several days has quickly dried out the native
grasses. This combined with drought conditions across the area plus
humidity levels between 25 and 30 percent and southwest winds gusting
to 20 to 25 mph will increase the risk of rapid fire growth which
could quickly burn out of control.
&&
.CLIMATE...
Issued at 352 AM CDT MON SEP 9 2013
Record or near record heat is expected Monday afternoon over parts of
northern and west central MO and extreme east central KS.
Sep 9 record high/year
St. Joseph 98/1955
Kansas City 99/1970
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...MJ
LONG TERM...Dux
AVIATION...Laflin
FIRE WEATHER...MJ
CLIMATE...MJ
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1131 AM CDT Mon Sep 9 2013
.UPDATE:
Issued at 552 AM CDT Mon Sep 9 2013
Did a quick update, a few isolated thunderstorms have developed
over Marion and Fayette counties in southern IL. Latest HRRR run
shows even more activity firing up this morning, but isolated in
nature that could affect more of the CWA. Will have to keep an eye
on radar this morning. For now just have mention in far eastern
counties through 14z.
Byrd
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 326 AM CDT Mon Sep 9 2013
Front to continue moving back north as a warm front this morning,
so the above normal weather to persist through the next several
days. However, there is some residual mid clouds from weak
shortwave that is sliding through the area early this morning. As
for chances of isolated showers with this shortwave, feel that
they will develop just south of forecast area today, so kept
forecast dry for now. Otherwise, these clouds should clear out
from northwest to southeast today. So with 850 temps aoa 22C over
the central plains, will see high temps in the 90s with the
warmest temps over northern MO, while southeast MO/southern IL to
be a bit slower in its warm up due to the lingering mid clouds.
Despite dewpts mixing out by this afternoon and lowering into the
low to mid 60s, heat index values in northeast MO/west central IL
will approach 100.
Byrd
.LONG TERM: (Tonight through Sunday)
Issued at 326 AM CDT Mon Sep 9 2013
Another very mild night tonight with lows only in the upper 60s
to mid 70s. Hot and humid weather to persist on Tuesday with highs
in the mid to upper 90s with lows Tuesday night in the upper 60s
to low 70s. With highs in the mid to upper 90s both today and
Tuesday, could be close to record highs for this time of year.
Wednesday to remain another above normal day, though a few degrees
cooler as cu pop up ahead of next frontal boundary. Models are a bit
slower with this front now, but should still see it move into the
forecast area Wednesday night. Still not a lot of pcpn expected with
this boundary, so just kept low chance pops for far northern
counties on Wednesday, then spread chance pops south across most of
forecast area Wednesday night.
Beyond that, front to slide south of forecast area during the day
Thursday with surface ridge building in. This will bring in cooler
and drier conditions for the rest of the forecast period. Highs will
be in the mid to upper 80s on Thursday, then drop into the mid 70s
to mid 80s for the remainder of the forecast period. Lows will be in
the 50s over the weekend.
Byrd
&&
.AVIATION: (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1103 AM CDT Mon Sep 9 2013
VFR through the period with southwesterly winds. Some light fog is
possible in favored valley locations tonight if the winds become
calm.
Specifics for KSTL: VFR through the period with southwesterly
winds.
Kanofsky
&&
.CLIMATE:
ISSUED AT 306 PM CDT SAT SEP 7 2013
RECORD HIGHS:
SEPT 9 SEPT 10
STL 101/1925 98/1983
COU 99/1925 99/1938
UIN 100/1945 100/1933
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
637 AM CDT Mon Sep 9 2013
.UPDATE:
Issued at 552 AM CDT Mon Sep 9 2013
Did a quick update, a few isolated thunderstorms have developed
over Marion and Fayette counties in southern IL. Latest HRRR run
shows even more activity firing up this morning, but isolated in
nature that could affect more of the CWA. Will have to keep an eye
on radar this morning. For now just have mention in far eastern
counties through 14z.
Byrd
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 326 AM CDT Mon Sep 9 2013
Front to continue moving back north as a warm front this morning,
so the above normal weather to persist through the next several
days. However, there is some residual mid clouds from weak
shortwave that is sliding through the area early this morning. As
for chances of isolated showers with this shortwave, feel that
they will develop just south of forecast area today, so kept
forecast dry for now. Otherwise, these clouds should clear out
from northwest to southeast today. So with 850 temps aoa 22C over
the central plains, will see high temps in the 90s with the
warmest temps over northern MO, while southeast MO/southern IL to
be a bit slower in its warm up due to the lingering mid clouds.
Despite dewpts mixing out by this afternoon and lowering into the
low to mid 60s, heat index values in northeast MO/west central IL
will approach 100.
Byrd
.LONG TERM: (Tonight through Sunday)
Issued at 326 AM CDT Mon Sep 9 2013
Another very mild night tonight with lows only in the upper 60s
to mid 70s. Hot and humid weather to persist on Tuesday with highs
in the mid to upper 90s with lows Tuesday night in the upper 60s
to low 70s. With highs in the mid to upper 90s both today and
Tuesday, could be close to record highs for this time of year.
Wednesday to remain another above normal day, though a few degrees
cooler as cu pop up ahead of next frontal boundary. Models are a bit
slower with this front now, but should still see it move into the
forecast area Wednesday night. Still not a lot of pcpn expected with
this boundary, so just kept low chance pops for far northern
counties on Wednesday, then spread chance pops south across most of
forecast area Wednesday night.
Beyond that, front to slide south of forecast area during the day
Thursday with surface ridge building in. This will bring in cooler
and drier conditions for the rest of the forecast period. Highs will
be in the mid to upper 80s on Thursday, then drop into the mid 70s
to mid 80s for the remainder of the forecast period. Lows will be in
the 50s over the weekend.
Byrd
&&
.AVIATION: (For the 12z TAFs through 12z Tuesday Morning)
Issued at 626 AM CDT Mon Sep 9 2013
Spotty showers have developed from the mid cloud deck present
across the area. Have even seen some lightning strikes well east
of the TAFS sites in south central IL. This precipitation should
dissipate by 15z or so with the mid clouds also becoming more
scattered. I have mentioned VCSH in the KCOU and St. Louis area
TAFS given the very low coverage, otherwise VFR conditions and
southwest winds will prevail today and tonight.
Specifics for KSTL:
Isolated showers have been noted in the St. Louis area associated
with the mid cloud deck present. This precipitation should
dissipate by 15z or so as the mid clouds become more scattered. I
have mentioned VCSH in the TAF given the very low coverage,
otherwise VFR conditions and southwest winds will prevail today
and tonight.
Glass
&&
.CLIMATE:
ISSUED AT 306 PM CDT SAT SEP 7 2013
RECORD HIGHS:
SEPT 9 SEPT 10
STL 101/1925 98/1983
COU 99/1925 99/1938
UIN 100/1945 100/1933
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
607 AM CDT Mon Sep 9 2013
.UPDATE...
Issued at 603 AM CDT MON SEP 9 2013
As noted in the 352 am discussion below an accas field has quickly
formed over the eastern portion of the CWA with widely scattered
elevated convection now being detected by radar. Have updated the
zones/grids to reflect this. Activity is expected to be short-lived
and dissipate by late morning.
&&
.SHORT TERM...(Today through Tuesday)
Issued at 352 AM CDT MON SEP 9 2013
The unseasonably hot conditions will continue today with near record
heat in parts of northern and west central MO. While H8 and 925mb
temperatures are progged to be 1-2C lower than Sunday when triple
digit readings were reached in the KC Metro, mixing will be better
and deeper due to increasing southwest winds. The net effect will be
afternoon temperatures topping out in the middle to upper 90s. If
there is any silver lining to today`s heat it`s the expectation of
lower humidity levels due to this better mixing.
The large anticyclone aloft will be nearly overhead and with its hot
mid level temperatures will suppress most cloud clover let alone any
convective development. However, there is one caveat to this
scenario and it revolves around a weak surface trough extending from
near OMA southeast through central MO. Some of the very short range
models like the RAP and HRRR are hinting at some elevated convection
near this boundary +/- 2-3 hours centered around 12Z. While the
models have been overly generous with qpf the last couple days with
the boundaries that have migrated into the CWA the latest satellite
imagery shows patches of apparently mid clouds forming from far east
central KS to central MO. Will need to monitor radar/satellite for
any development as the current forecast is dry.
Tuesday: more of the same although temperatures look like they will
be a few degrees cooler as the pool of hot air shifts northward.
Nonetheless, temperatures will remain a good 10F above average.
Lacking any boundary and with nearly non-existent moisture under a
strong cap will go with zero PoPs.
Tuesday night: A cold front from southern NE through WI will sag
slowly southward and possibly reach far northwest MO by Wednesday
morning. Models are becoming more reluctant to generate qpf over the
CWA as any convection which forms during this period will likely be
post-frontal. Have confined PoPs to far northwest MO and left rest
of CWA dry.
.LONG TERM...(Wednesday through Sunday)
Issued at 352 AM CDT MON SEP 9 2013
A rather weak front is expected to sink into northern Missouri by
Wednesday morning, but with limited precipitation accompanying it.
A narrow corridor of low level moisture will stretch across southern
Nebraska eastward into central Illinois into Thursday. Depending on
cloud cover, temperatures may again climb into the lower or even
middle 90s Wednesday afternoon and while low, a few thunderstorms
may develop in the unstable airmass south of the boundary.
Slightly higher PoPs are focused Wednesday night into Thursday as
the low-level baroclinic zone shifts southward. However, the LLJ
will back through the night into NW Kansas and SW Nebraska likely
forcing higher precipitation chances well west of the local area.
A secondary cold front will sweep into the area Thursday night,
allowing cool and dry air to push southwest. Temperatures heading
into the weekend will find themselves near the seasonal normals in
the upper 70s to lower 80s. An upper low crossing the Rockies over
the weekend will allow winds to turn back southwesterly on Saturday,
before another front moves into the area Sunday/Monday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
Issued at 603 AM CDT MON SEP 9 2013
VFR conditions with little if any cloud cover during the period.
Primary concerns will center on the expected increase in
southwesterly winds by mid morning. Winds will remain gusty through
the entire afternoon before diminishing quickly shortly before sunset.
&&
.FIRE WEATHER...
Issued at 352 AM CDT MON SEP 9 2013
There is an elevated fire danger threat this afternoon across
northern and west central MO as well as extreme east central KS. The
heat of the past several days has quickly dried out the native
grasses. This combined with drought conditions across the area plus
humidity levels between 25 and 30 percent and southwest winds gusting
to 20 to 25 mph will increase the risk of rapid fire growth which
could quickly burn out of control.
&&
.CLIMATE...
Issued at 352 AM CDT MON SEP 9 2013
Record or near record heat is expected Monday afternoon over parts of
northern and west central MO and extreme east central KS.
Sep 9 record high/year
St. Joseph 98/1955
Kansas City 99/1970
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...MJ
LONG TERM...Dux
AVIATION...MJ
FIRE WEATHER...MJ
CLIMATE...MJ
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
555 AM CDT Mon Sep 9 2013
.UPDATE:
Issued at 552 AM CDT Mon Sep 9 2013
Did a quick update, a few isolated thunderstorms have developed
over Marion and Fayette counties in southern IL. Latest HRRR run
shows even more activity firing up this morning, but isolated in
nature that could affect more of the CWA. Will have to keep an eye
on radar this morning. For now just have mention in far eastern
counties through 14z.
Byrd
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 326 AM CDT Mon Sep 9 2013
Front to continue moving back north as a warm front this morning,
so the above normal weather to persist through the next several
days. However, there is some residual mid clouds from weak
shortwave that is sliding through the area early this morning. As
for chances of isolated showers with this shortwave, feel that
they will develop just south of forecast area today, so kept
forecast dry for now. Otherwise, these clouds should clear out
from northwest to southeast today. So with 850 temps aoa 22C over
the central plains, will see high temps in the 90s with the
warmest temps over northern MO, while southeast MO/southern IL to
be a bit slower in its warm up due to the lingering mid clouds.
Despite dewpts mixing out by this afternoon and lowering into the
low to mid 60s, heat index values in northeast MO/west central IL
will approach 100.
Byrd
.LONG TERM: (Tonight through Sunday)
Issued at 326 AM CDT Mon Sep 9 2013
Another very mild night tonight with lows only in the upper 60s
to mid 70s. Hot and humid weather to persist on Tuesday with highs
in the mid to upper 90s with lows Tuesday night in the upper 60s
to low 70s. With highs in the mid to upper 90s both today and
Tuesday, could be close to record highs for this time of year.
Wednesday to remain another above normal day, though a few degrees
cooler as cu pop up ahead of next frontal boundary. Models are a bit
slower with this front now, but should still see it move into the
forecast area Wednesday night. Still not a lot of pcpn expected with
this boundary, so just kept low chance pops for far northern
counties on Wednesday, then spread chance pops south across most of
forecast area Wednesday night.
Beyond that, front to slide south of forecast area during the day
Thursday with surface ridge building in. This will bring in cooler
and drier conditions for the rest of the forecast period. Highs will
be in the mid to upper 80s on Thursday, then drop into the mid 70s
to mid 80s for the remainder of the forecast period. Lows will be in
the 50s over the weekend.
Byrd
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1142 PM CDT Sun Sep 8 2013
Primary concern for the rest of the night remains the probability
of isolated-widely scattered showers and thunderstorms
redeveloping along and east of the Mississippi River. It looks
like the best chance has shifted mostly to south of the St. Louis
Metro area across parts of the eastern Ozarks and southwest
Illinois. It does not look like a particularly strong or organized
round of showers and storms, but the signals in the models aren`t
very strong so confidence is low. VFR flight conditions should
prevail outside of any precipitation, except in area river valleys
where intermittent MFR conditions in fog can be expected.
VFR flight conditions are expected to prevail on Monday. The wind
will be increasing from the southwest with potential for gusts to
around 20kits especially across parts of central and northern
Missouri as well as west central Illinois.
Specifics for KSTL:
Expect VFR flight conditions to prevail for the rest of the night
at Lambert. Isolated showers are still possible...but the best
chances for rain look to have moved south/southeast of the
terminal. Signals in the models for rain aren`t particularly well
defined, so confidence in timing and locations of the showers is
low. River valley fog can be expected west of the terminal, but
shouldn`t impact the runway complex.
VFR flight conditions are expected to continue to prevail on
Monday. The wind will be increasing from the southwest in the
morning...and this will likely cause a brief period of direct
crosswinds on the main runways. However, the wind should continue
veering past 210 degrees by mid-late morning.
Carney
&&
.CLIMATE:
ISSUED AT 306 PM CDT SAT SEP 7 2013
RECORD HIGHS:
SEPT 9 SEPT 10
STL 101/1925 98/1983
COU 99/1925 99/1938
UIN 100/1945 100/1933
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
400 AM CDT Mon Sep 9 2013
.SHORT TERM...(Today through Tuesday)
Issued at 352 AM CDT MON SEP 9 2013
The unseasonably hot conditions will continue today with near record
heat in parts of northern and west central MO. While H8 and 925mb
temperatures are progged to be 1-2C lower than Sunday when triple
digit readings were reached in the KC Metro, mixing will be better
and deeper due to increasing southwest winds. The net effect will be
afternoon temperatures topping out in the middle to upper 90s. If
there is any silver lining to today`s heat it`s the expectation of
lower humidity levels due to this better mixing.
The large anticyclone aloft will be nearly overhead and with its hot
mid level temperatures will suppress most cloud clover let alone any
convective development. However, there is one caveat to this
scenario and it revolves around a weak surface trough extending from
near OMA southeast through central MO. Some of the very short range
models like the RAP and HRRR are hinting at some elevated convection
near this boundary +/- 2-3 hours centered around 12Z. While the
models have been overly generous with qpf the last couple days with
the boundaries that have migrated into the CWA the latest satellite
imagery shows patches of apparently mid clouds forming from far east
central KS to central MO. Will need to monitor radar/satellite for
any development as the current forecast is dry.
Tuesday: more of the same although temperatures look like they will
be a few degrees cooler as the pool of hot air shifts northward.
Nonetheless, temperatures will remain a good 10F above average.
Lacking any boundary and with nearly non-existent moisture under a
strong cap will go with zero PoPs.
Tuesday night: A cold front from southern NE through WI will sag
slowly southward and possibly reach far northwest MO by Wednesday
morning. Models are becoming more reluctant to generate qpf over the
CWA as any convection which forms during this period will likely be
post-frontal. Have confined PoPs to far northwest MO and left rest
of CWA dry.
.LONG TERM...(Wednesday through Sunday)
Issued at 352 AM CDT MON SEP 9 2013
A rather weak front is expected to sink into northern Missouri by
Wednesday morning, but with limited precipitation accompanying it.
A narrow corridor of low level moisture will stretch across southern
Nebraska eastward into central Illinois into Thursday. Depending on
cloud cover, temperatures may again climb into the lower or even
middle 90s Wednesday afternoon and while low, a few thunderstorms
may develop in the unstable airmass south of the boundary.
Slightly higher PoPs are focused Wednesday night into Thursday as
the low-level baroclinic zone shifts southward. However, the LLJ
will back through the night into NW Kansas and SW Nebraska likely
forcing higher precipitation chances well west of the local area.
A secondary cold front will sweep into the area Thursday night,
allowing cool and dry air to push southwest. Temperatures heading
into the weekend will find themselves near the seasonal normals in
the upper 70s to lower 80s. An upper low crossing the Rockies over
the weekend will allow winds to turn back southwesterly on Saturday,
before another front moves into the area Sunday/Monday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday Night)
Issued at 1152 PM CDT SUN SEP 8 2013
VFR conditions are expected through the period. Primarily a wind
forecast, with south-southwesterly wind speeds increasing by late
morning and decreasing around sunset.
&&
.FIRE WEATHER...
Issued at 352 AM CDT MON SEP 9 2013
There is an elevated fire danger threat this afternoon across
northern and west central MO as well as extreme east central KS. The
heat of the past several days has quickly dried out the native
grasses. This combined with drought conditions across the area plus
humidity levels between 25 and 30 percent and southwest winds gusting
to 20 to 25 mph will increase the risk of rapid fire growth which
could quickly burn out of control.
&&
.CLIMATE...
Issued at 352 AM CDT MON SEP 9 2013
Record or near record heat is expected Monday afternoon over parts of
northern and west central MO and extreme east central KS.
Sep 9 record high/year
St. Joseph 98/1955
Kansas City 99/1970
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
SHORT TERM...MJ
LONG TERM...Dux
AVIATION...Blair
FIRE WEATHER...MJ
CLIMATE...MJ
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1155 PM CDT Sun Sep 8 2013
.UPDATE:
Issued at 856 PM CDT Sun Sep 8 2013
Scattered showers that were over the eastern Ozark counties
earlier this evening rotated south around the upper high that is
currently centered over northwest Missouri. The RAP/HRRR still
indicates the potential for the redevelopment of thunderstorms
along and east of the Mississippi river between 06-12Z tonight, so
have concentrated slight chances of rain the rest of the night in
these locations. This is where the HRRR develops N-S band of
storms in an area of 925-850mb moisture convergence seen on the
RAP. Some fog will also be possible tonight where skies clear
with light winds, particularly where heavy rain fell earlier
today.
Britt
&&
.SHORT TERM: (Through Late Tonight)
Issued at 335 PM CDT Sun Sep 8 2013
The primary forecast issue for tonight is precipitation chances.
Unfortunately, this is not a straightforward forecast. The cold
front which was supposed to have moved through the CWA last night
has instead stalled near the MO/IA border, and the MCS which moved
through the CWA earlier today has also changed the situation with
respect to precipitation chances for tonight.
First, the aforementioned MCS produced several hours of steady
rainfall across most of the CWA, significantly moistening the lower
levels of the atmosphere. Second, differential heating between the
clear skies over western MO and the MCS-generated clouds over
eastern MO has produced a surface boundary that resembles a warm
front, including surface convergence noted on afternoon METARs. This
feature stretched from NW MO to near KCOU and then southward into
the Ozarks, and it is distinct from the true synoptic warm front
which was located from the Dakotas through IA and MN and then into
northern IL. Third, a persistent cluster of showers and
thunderstorms has already developed over extreme northwestern MO.
Model forecasts suggest that the H85 LLJ will interact with the
synoptic warm front well to our north tonight, and this scenario
still looks very reasonable. However, our concern is whether
additional thunderstorms will develop farther south, mainly across
parts of MO. H85 winds to the southeast of the main LLJ core are
forecast to veer with time and would impinge on the convergence zone
(remnant of the differential heating boundary), if it still exists,
and the overnight MUCAPE axis is forecast to extend into the LSX
CWA. Admittedly, there are a lot of "ifs" and "mights" when it comes
to thunderstorm chances tonight, but there`s enough substance here
to warrant slight chance PoPs until the atmosphere shows its hand
over the next several hours.
Kanofsky
.LONG TERM: (Monday through Next Sunday)
Issued at 335 PM CDT Sun Sep 8 2013
12z guidance continues to support the thinking that hot September
weather will dominate the region on Monday and Tuesday as the upper
ridge shifts east into the Ohio valley. This mornings UA data
indicated 850 mb temps aoa 24C over a large section of the central
plains, and this air should advect into the mid-Mississippi valley
with time. Some residual cloudiness may hinder the warm up just a
bit over our far se counties, but with this thermal ridge punching
across the n half of our CWA temps should easily be in the mid-upper
90s both Monday and Tuesday. It`s not out of the question that some
areas will approach the century mark due to deep mixing in this hot
airmass with a pronounced westerly component to the low level flow
and strong sunshine. And, (in spite of todays rain) dry soil and
vegetation remains in many areas, and especially in those locations
north of highway 36 where little if any rain fell today.
Aforementioned mixing should allow a fairly substantial drop in
dewpoints during the afternoon hours, especially in the hottest air
over n sections of the CWA. Calculated hourly apparent temperatures
based on this thinking is still capping the HI at around 100 in some
spots, so no heat headlines needed at this time.
As far as rain potential is concerned, if storms do form
overnight believe that most of them will be drifting out of the
area by morning. Based on development and timing its possible
later shifts may have to hang onto some pops for early Monday
morning, but due to considerable uncertainty on location, timing,
and even occurrence of overnight convection have maintained a
rain-free forecast for Monday morning. Another nagging concern is
the spotty rainfall that the NAM, GFS, and even the ECMWF have
been trying to generate over our southeast counties over the past
few days. 12z runs are also hinting at this, but are a bit more
sporadic with this than earlier solutions. The only mechanism I
can see for this is ams-type diurnal convection, perhaps aided by
a bit of orographic lift into the eastern Ozarks. However,
directly beneath an upper ridge seems like an odd place for this
to occur (current activity going up near STJ notwithstanding). At
this point will maintain dry forecast, and let mid shift take
another look at short range guidance to determine if the inclusion
of POPs is warranted.
Latest medium range guidance also hasn`t changed much in their
handling of cold front and its southward push across the mid-
Mississippi valley in the Wednesday night-Thursday time frame as
upper trof begins to develop over the eastern CONUS. Have kept
POPs in the chance category for now due to rather weak dynamics
and what appears to be limited convergence along the front.
Since fropa won`t occur in our area until Wednesday night have
kept Wednesdays temps aoa guidance in all but northern sections
of the CWA where some afternoon clouds and convection will be
possible. Going temp trends for remainder of the extended (which
reflect continued cooling into Saturday) still look reasonable as
large Canadian high builds into the eastern U.S.
Truett
&&
.AVIATION: (For the 06z TAFs through 06z Monday Night)
Issued at 1142 PM CDT Sun Sep 8 2013
Primary concern for the rest of the night remains the probability
of isolated-widely scattered showers and thunderstorms
redeveloping along and east of the Mississippi River. It looks
like the best chance has shifted mostly to south of the St. Louis
Metro area across parts of the eastern Ozarks and southwest
Illinois. It does not look like a particularly strong or organized
round of showers and storms, but the signals in the models aren`t
very strong so confidence is low. VFR flight conditions should
prevail outside of any precipitation, except in area river valleys
where intermittent MFR conditions in fog can be expected.
VFR flight conditions are expected to prevail on Monday. The wind
will be increasing from the southwest with potential for gusts to
around 20kits especially across parts of central and northern
Missouri as well as west central Illinois.
Specifics for KS TL:
Expect VFR flight conditions to prevail for the rest of the night
at Lambert. Isolated showers are still possible...but the best
chances for rain look to have moved south/southeast of the
terminal. Signals in the models for rain aren`t particularly well
defined, so confidence in timing and locations of the showers is
low. River valley fog can be expected west of the terminal, but
shouldn`t impact the runway complex.
VFR flight conditions are expected to continue to prevail on
Monday. The wind will be increasing from the southwest in the
morning...and this will likely cause a brief period of direct
crosswinds on the main runways. However, the wind should continue
veering past 210 degrees by mid-late morning.
Carney
&&
.CLIMATE:
ISSUED AT 306 PM CDT SAT SEP 7 2013
RECORD HIGHS:
SEPT 9 SEPT 10
STL 101/1925 98/1983
COU 99/1925 99/1938
UIN 100/1945 100/1933
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
647 PM CDT TUE SEP 10 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 317 PM CDT TUE SEP 10 2013
MORNING MAP ANALYSIS INDICATES A CLOSED MID LEVEL LOW OVER THE
SOUTHWESTERN CONUS...WITH RIDGING OVER THE EAST. A MID LEVEL
SHORTWAVE IS ALSO NOTED OVER SOUTH CENTRAL CANADA AND MOVING EAST.
THE PRIMARY AXIS OF MID TO UPPER LEVEL JET ENERGY EXTENDS FROM
WESTERN CANADA...SOUTHEAST INTO THE NORTHERN PLAINS...AND THEN
EAST/NORTHEAST INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW
IS FAIRLY WEAK OVER OUR AREA AS A RESULT...ONLY MAXING OUT AT
AROUND 30KTS AT VARIOUS POINT BETWEEN 500MB AND 200MB PER 12Z
SOUNDING DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY ALSO SHOWS
THE AFOREMENTIONED MID LEVEL LOW OVER THE SOUTHWESTERN CONUS...AS
WELL AS THE MID LEVEL SHORTWAVE OVER SOUTH CENTRAL CANADA. THE MID
LEVEL LOW OVER THE SOUTHWESTERN CONUS IS HELPING PULL MID LEVEL
MOISTURE NORTHWARD FROM MEXICO AND AS A RESULT...INCREASED VALUES
OF MID LEVEL MOISTURE ARE NOTED EXTENDING FROM THE SOUTHWESTERN
CONUS...NORTHEAST INTO THE ROCKY MOUNTAIN RANGE AND INTO PORTIONS
OF THE NORTHERN AND CENTRAL PLAINS. AT THE SURFACE A NEARLY
STATIONARY BOUNDARY IS NOTED EXTENDING FROM WESTERN KANSAS INTO
EASTERN NEBRASKA AND WESTERN IOWA. THIS BOUNDARY BISECTS OUR CWA
AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS THE NORTHWESTERN
HALF OF OUR CWA REMAINS FROM THE NORTHEAST...WHILE LOCATIONS
FARTHER SOUTHEAST CONTINUE TO OBSERVE A SOUTHWESTERLY LOW LEVEL
WIND FIELD.
TO THE SOUTH OF THE LOW LEVEL BAROCLINIC ZONE...AFTERNOON SURFACE
TEMPERATURES HAVE CLIMBED WELL INTO THE 90S...WITH PROXIMITY
SOUNDINGS FROM LAPS AND RAP ANALYSIS INDICATING CONVECTIVE
TEMPERATURES HAVE BEEN REACHED. KUEX INDICATES ISOLATED SHOWER AND
THUNDERSTORM ACTIVITY DEVELOPING FROM WESTERN KANSAS INTO NORTH
CENTRAL KANSAS...INCLUDING SOUTHERN PORTIONS OF OUR CWA. THESE
SAME PROXIMITY SOUNDINGS SUGGEST ~1000J/KG OF POTENTIAL ENERGY IS
READY FOR UPDRAFT PRODUCTION...BUT VERY LITTLE IN THE WAY OF DEEP
LAYER BULK SHEAR IS PRESENT...PERHAPS NO HIGHER THAN 15 OR 20KTS.
GIVEN ALL THIS...ISOLATED SHOWER AND THUNDERSTORM ACTIVITY WILL
LIKELY PERSIST ACROSS SOUTHEASTERN PORTIONS OF OUR CWA THROUGH THE
REST OF THIS AFTERNOON. MULTIPLE SETS OF GUIDANCE SUGGEST LOW
LEVEL CONVERGENCE AND RESULTANT FORCING ALONG THE LOW LEVEL
BAROCLINIC ZONE MAY ALSO PROMOTE ISOLATED TO SCATTERED SHOWER AND
THUNDERSTORM CONVECTION ACROSS THE AREA. AS A RESULT...KEPT THE
~20% POP GOING ACROSS MUCH OF THE CWA 21-00Z.
ANY SURFACE-BASED CONVECTION THAT CAN BE REALIZED THIS AFTERNOON
AND/OR EVENING ACROSS OUR SOUTHERN COUNTIES...OR FARTHER NORTH
ALONG THE LOW LEVEL BAROCLINIC ZONE...SHOULD DISSIPATE SHORTLY
AFTER SUNSET AS DIABATIC HEATING IS LOST. THAT BEING
SAID...GUIDANCE SUGGESTS THE MID LEVEL SHORTWAVE...CURRENTLY OVER
SOUTH CENTRAL CANADA...WILL MOVE SOUTHEAST THUS PUSHING THE MID
LEVEL JET AXIS FARTHER SOUTH AS WELL. THIS WILL IN TURN PUSH A
30-40KT MID LEVEL JET STREAK FARTHER SOUTH INTO THE UPPER
MISSISSIPPI VALLEY AND PORTIONS OF THE NORTHERN PLAINS...WITH THE
RIGHT-REAR QUADRANT OF THIS JET STREAK SETTING UP OVER NORTHERN
PORTIONS OF OUR CWA. IT APPEARS AS THOUGH THERE WILL BE ENOUGH OF
A THERMALLY-DIRECT CIRCULATION AND RESULTANT OMEGA FOR ADDITIONAL
SHOWER AND THUNDERSTORM DEVELOPMENT...PRIMARILY ACROSS OUR
NORTH...OVERNIGHT TONIGHT AND AS A RESULT...~30% POPS HAVE BEEN
PLACED PRIMARILY ACROSS THE NORTHERN HALF OF OUR CWA 00-12Z
WEDNESDAY.
THERE MAY BE SOME LINGERING SHOWER AND THUNDERSTORM ACTIVITY EARLY
WEDNESDAY MORNING...BUT GUIDANCE SUGGESTS THIS ACTIVITY SHOULD
DISSIPATE BY AROUND SUNRISE. DRY CONDITIONS WILL MORE THAN LIKELY
BE OBSERVED THROUGH MUCH OF THE DAY WEDNESDAY...HOWEVER THE LOW
LEVEL BAROCLINIC ZONE...CURRENTLY OVER CENTRAL PORTIONS OF OUR
CWA...IS ONLY EXPECTED TO SHIFT SLIGHTLY SOUTH TONIGHT AND BY
WEDNESDAY AFTERNOON IS EXPECTED TO STRETCH ACROSS THE SOUTHEASTERN
ONE-THIRD OF OUR CWA. LOW LEVEL CONVERGENCE AND RESULTANT FORCING
ALONG THE LOW LEVEL BAROCLINIC ZONE MAY PROMOTE ANOTHER ROUND OF
AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY ON WEDNESDAY AND AS A
RESULT...20-30% POPS HAVE BEEN PLACED ACROSS PORTIONS OF THE CWA
FOR WEDNESDAY AFTERNOON AND EVENING...WITH THE HIGHEST POPS
RELEGATED TO OUR SOUTHEAST IN CLOSEST PROXIMITY TO THE LOW LEVEL
BAROCLINIC ZONE.
GUIDANCE SUGGESTS POTENTIAL ENERGY WILL NOT CLIMB MUCH HIGHER THAN
1000J/KG THIS AFTERNOON AND EVENING...AND WITH LITTLE IN THE WAY
OF DEEP LAYER BULK SHEAR...THE THREAT FOR SEVERE WEATHER SEEMS
FAIRLY LIMITED. THAT BEING SAID...THERE IS A CHANCE UPDRAFT
STRENGTH COULD BE STRONG ENOUGH TO PROMOTE SOME HAIL...CURRENTLY
EXPECTED TO REMAIN SUB-SEVERE...AND SO WILL OUTLOOK THIS IN THE
HWO. IN ADDITION...FORECAST PROXIMITY SOUNDINGS SUGGEST FAIRLY
DEEP INVERTED-V SOUNDINGS...TO BETWEEN 800MB AND 750MB...COULD
ALSO PROMOTE A WIND GUST THREAT. WILL GO AHEAD AND OUTLOOK BRIEF
WIND GUSTS TO AROUND 50 MPH IN THE HWO FOR THIS AFTERNOON AND
EVENING AS WELL. TROPOSPHERIC CONDITIONS...FOR LOCATIONS NEAR AND
AHEAD OF THE LOW LEVEL BAROCLINIC ZONE...APPEAR AS THOUGH THEY
WILL BE SIMILAR ON WEDNESDAY WHEN COMPARED TO TODAY AND AS A
RESULT...WILL GO AHEAD AND OUTLOOK THE THREAT FOR SUB-SEVERE HAIL
AND WIND GUSTS...PRIMARILY ACROSS OUR SOUTH...FOR WEDNESDAY
AFTERNOON AND EVENING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 317 PM CDT TUE SEP 10 2013
WEDNESDAY NIGHT...THE SFC COOL FRONT WILL REMAIN WELL TO THE SOUTH
OF OUR FORECAST AREA AND WILL LIKELY BE LOCATED OVER OKLAHOMA. AN
UPPER LEVEL TROUGH WILL BE SCOOTING TO OUR NORTHEAST AND THE BEST
CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ASSOCIATED WITH AN
OVERRUNNING SET UP ACROSS KANSAS. NEBRASKA WILL BE SO FAR NORTH OF
THE FRONT WITH DRIER AIR STARTING TO WORK IN AND HENCE LESSER POPS
AS YOU HEAD NORTH THROUGH OUR NEBRASKA ZONES.
THURSDAY AND FRIDAY...A SFC HIGH WILL SLIDE INTO THE GREAT LAKES
RESULTING IN A WIND SHIFT AS WE BEGIN TO GET MORE OF AN EASTERLY
UPSLOPE FLOW ON THURSDAY AND THEN A RETURN SOUTHEASTERLY STILL
SOMEWHAT UPSLOPE FLOW ON FRIDAY. THIS WILL RESULT IN THUNDERSTORM
CHANCES ACROSS THE HIGH PLAINS AND THEN SLIGHT CHANCES OF SHOWERS
AND THUNDERSTORMS ACROSS OUR FAR SOUTHWESTERN COUNTIES AS WESTERN
THUNDERSTORMS TRY TO MAKE IT EAST...BUT WILL LIKELY STRUGGLE. THE
TRI CITIES AND POINTS NORTH AND EAST ARE LIKELY GOING TO BE DRY
DURING THIS PERIOD. TEMPERATURES SHOULD BE BELOW NORMAL FOR THE
FIRST TIME SINCE AROUND THE MIDDLE OF AUGUST...WHICH WAS THE LAST
TIME WE SAW HIGHS ONLY IN THE 70S. ALTHOUGH BOTH THURSDAY AND
FRIDAY WILL BE COOL IN THE 70S FOR HIGHS...FRIDAY WILL BE THE
COOLEST OF THE TWO DAYS WITH HIGHS ONLY IN THE LOWER TO MID 70S.
WEEKEND...THE COOL WEATHER WILL PERSIST WITH CLOUDS AND SEVERAL
CHANCES OF SHOWERS AND THUNDERSTORMS AS WEAK PIECES OF A SHORTWAVE
TROUGH TRACK THROUGH THE CENTRAL PLAINS. PRECIPITATION CHANCES
SEEM FAIR GENERALLY IN THE 30 TO 40 PERCENT RANGE. THESE CHANCES
MAY BE RAISED IN COMING DAYS IF CURRENT WET LOOKING MODEL TRENDS
CONTINUE. HIGHS SHOULD CONTINUE TO BE IN THE 70S ACROSS NEBRASKA
TO NEAR 80 IN KANSAS. HOWEVER...COULD SEE THESE HIGHS BEING
LOWERED...PARTICULARLY ON SUNDAY...IF RAIN CHANCES INCREASE DUE TO
CLOUDS AND COOLER EAST NORTHEASTERLY FLOW. CONSEQUENTLY...THIS IS
A HEADS UP THAT OUR FORECAST HIGHS ARE CURRENTLY ON THE WARMER END
OF THE MODEL GUIDANCE...SO DO NOT BE SURPRISED IF HIGHS ARE
LOWERED WITH FUTURE FORECAST UPDATES.
MONDAY AND TUESDAY...CONFIDENCE IS LOW WITH SOME MODELS INDICATING
CONTINUED SHORT WAVES AND THUNDERSTORM CHANCES WHILE OTHER
FORECAST MODELS DRY OUT. POPS WILL BE LOW DUE TO UNCERTAINTY.
TEMPERATURES SHOULD BE SOMEWHAT NEAR NORMAL AND WILL BE CALLING
FOR HIGHS IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 633 PM CDT TUE SEP 10 2013
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KGRI FOR THE NEXT 24
HOURS. THE COLD FRONT THAT PASSED THE TERMINAL EARLIER THIS
AFTERNOON HAS BEEN FIRING UP SHRAS AND TSRAS SOUTH OF I-80 THE
PAST FEW HOURS...BUT SO FAR CONVECTION HAS REMAINED OUT OF THE
VICINITY OF KGRI. EXPECT THIS TO CONTINUE TO BE THE RULE AT THE
TERMINAL OVER THE NEXT FEW HOURS...UNTIL THESE TSRAS AND SHRAS
DIMINISH AROUND SUNSET. COULD SEE SOME CONVECTION CLOSER TO THE
TERMINAL OVERNIGHT AS SOME JET ENERGY ATTEMPTS TO PROMOTE
ADDITIONAL DEVELOPMENT...BUT CONFIDENCE OF A TSRA CROSSING THE
TERMINAL IS LOW...SO COVERED BOTH CHANCES THIS AFTERNOON AND
OVERNIGHT WITH A CB AT THIS TIME. OTHERWISE...LIGHT NORTHEASTERLY
WINDS WILL CONTINUE AT THE TERMINAL FOR THE NEXT 24 HOURS AS THE
MAIN COLD FRONT IS EXPECTED TO REMAIN SOUTH OF THE LOCAL AREA.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...WESELY
AVIATION...SAR
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
1024 AM PDT MON SEP 9 2013
.SYNOPSIS....SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE ACROSS MUCH
OF THE AREA THROUGH WEDNESDAY WITH A DRYING TREND ON THE HORIZON FOR
THE LATTER PART OF THE WEEK. TEMPERATURES TO REMAIN BELOW NORMAL
THROUGH MID WEEK THEN WARM BACK TO NEAR OR SLIGHTLY ABOVE NORMAL AS
THE WEEKEND APPROACHES.
&&
.UPDATE...SCATTERED LIGHT SHOWERS MOVED ACROSS THE SOUTH END OF THE
LAS VEGAS VALLEY EARLIER THIS MORNING BRINGING MEASURABLE RAIN TO
SOME NEIGHBORHOODS. THESE HAVE SINCE MOVED OUT. LOOKING AHEAD TO
THIS AFTERNOON THE MOST ACTIVE AREAS LOOK TO BE MOHAVE AND EASTERN
SAN BERNARDINO COUNTIES INITIALLY. MOHAVE COUNTY HAS HAD QUITE A BIT
OF SUNSHINE THIS MORNING WHICH SHOULD HELP TO DESTABILIZE THE
ATMOSPHERE AND TRIGGER CONVECTION. ACROSS EASTERN SAN BERNARDINO
COUNTY COULD MID-LEVEL CONVERGENCE ON THE BACK SIDE OF THE MID/UPPER
LEVEL LOW IS SHOWN IN THE MODELS WHICH SHOULD HELP TO FORCE
CONVECTION HERE. THE HRRR MODEL CONFIRMS THESE AS BEING THE MOST
ACTIVE SPOTS THIS AFTERNOON AND WHERE WE MAY SEE THE FIRST ISSUES
WITH ANY HEAVIER STORMS FOR FLASH FLOODING. I CONSIDERED GOING WITH
A WATCH FOR THESE AREAS BUT THE COVERAGE OF HEAVIER STORMS IS STILL
QUESTIONABLE AT THIS TIME.
LOOKING AHEAD TO THIS EVENING, WE HAVE A NORTHEAST STEERING FLOW IN
PLACE ACROSS CLARK COUNTY COURTESY OF THE MID/UPPER LEVEL LOW TO OUR
SOUTH. THIS HAS BEEN A PATTERN IN THE PAST THAT HAS PRODUCED SOME
SIGNIFICANT STORMS FOR LAS VEGAS INCLUDING THE JULY 18 1994 HILTON
SIGN THUNDERSTORM EVENT AND MORE RECENTLY THE JULY 19TH EVENT THIS
YEAR. THE HRRR MODEL AS WELL AS THE NMM SURFACE WINDS AND WRF MODEL
QPF ALL HINT AT THE POTENTIAL FOR EITHER AN OUTFLOW BOUNDARY OR
CONVECTION TO MOVE IN FROM THE NORTHEAST THIS EVENING BETWEEN 6 AND
10 PM INTO NORTHEAST CLARK COUNTY AND EVENTUALLY LAS VEGAS. I DID GO
AHEAD AND ADJUST UP POPS IN THESE AREAS BY 10-15 PERCENT TO ACCOUNT
FOR THIS. STILL SOME UNCERTAINTY WITH THIS...BUT IT WILL BE WORTH
SEEING HOW THINGS PROGRESS AS TODAY UNFOLDS.
&&
.AVIATION...FOR MCCARRAN...GENERALLY LIGHT WINDS FROM THE EAST TO
SOUTHEAST TO CONTINUE TODAY WITH SPEEDS EXPECTED TO BE LESS THAN 9
KTS. SCATTERED THUNDERSTORMS ARE EXPECTED OVER THE SPRING MOUNTAINS
THIS AFTERNOON. THE WEATHER PATTERN IS FAVORABLE FOR A CHANCE OF
LATE EVENING THUNDERSTORMS COMING DOWN THE MORMON MESA CORRIDOR INTO
THE LAS VEGAS VALLEY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SCATTERED SHOWERS AND THUNDERSTORMS REDEVELOP THIS
AFTERNOON ACROSS MUCH OF THE AREA. SCT-BKN CLOUDS GENERALLY 10-15K
FEET TODAY IN THE EAST AND SOUTH WITH SKC-FEW CLOUDS AROUND 15K FEET
WEST. PREVAILING WINDS OUTSIDE OF STORM INFLUENCES SHOULD GENERALLY
REMAIN UNDER 10 KTS.
&&
.PREVIOUS DISCUSSION...
ISSUED AT 228 AM PDT MON SEP 9 2013
.SHORT TERM...THROUGH TUESDAY NIGHT...SATELLITE IMAGERY CLEARLY
SHOWS A CLOSED LOW CIRCULATING OVER FAR SOUTHERN NEVADA ENHANCING
CLOUD COVER AND SHOWERS TO ITS NORTH. AT 1 AM...RADAR WAS SHOWING
ENHANCED SHOWER ACTIVITY TO THE EAST OF LAS VEGAS MOVING WEST. BASED
ON THE PLACEMENT OF THIS WELL DEVELOPED CIRCULATION...THE VALLEY
STANDS A DECENT CHANCE OF SEEING RAIN SHOWERS OVER THE NEXT FEW
HOURS.
THE CIRCULATION IS FORECAST TO REMAIN NEARLY STATIONARY THROUGH THE
DAY WITH A DEFORMATION AXIS FORECAST NEAR THE MOHAVE/CLARK COUNTY
BORDER. MOISTURE/INSTABILITY PARAMETERS POINT TO CENTRAL AND EASTERN
SAN BERNARDINO...CLARK AND MOHAVE COUNTIES AS THE PRIMARY LOCATIONS
FOR STORM DEVELOPMENT TODAY. WITH CLOUD COVER FORECAST TO THIN OR
DISSOLVE ACROSS THE WEST AND REMAIN PARTLY TO MOSTLY CLOUDY IN THE
EAST...DIFFERENTIAL HEATING WILL LIKELY PLAY A ROLE ALONG THIS
BOUNDARY TO HELP INITIATE AND FOCUS STORMS IN ADDITION TO THE
DYNAMICS PROVIDED BY THE CLOSED CIRCULATION. THERE ARE TOO MANY
VARIABLES IN PLAY TO PINPOINT THE EXACT LOCATION OF THE MOISTURE
BOUNDARY AND WHERE THE STRONGEST STORMS WILL FORM BUT LOCALIZED
FLASH FLOODING IS CERTAINLY A POSSIBILITY AGAIN TODAY.
HEADING INTO TUESDAY...BROAD LOW PRESSURE IS FORECAST OVER THE CWA
WITH ANY NUMBER OF MESO SCALE CIRCULATIONS POSSIBLE. EASTERN SAN
BERN...CLARK...LINCOLN AND MOHAVE COUNTIES APPEAR TO BE THE PRIMARY
FOCUSING AREA FOR THUNDERSTORM DEVELOPMENT. TEMPERATURES WILL REMAIN
WELL BELOW NORMAL TODAY AND TUESDAY.
.LONG TERM...WEDNESDAY THROUGH MONDAY. THE MODELS HAVE COME INTO A
LITTLE BETTER AGREEMENT ON A DRYING TREND FROM SOUTHWEST TO
NORTHEAST THURSDAY THROUGH SATURDAY. FOR WEDNESDAY...WEAK UPPER LOW
OVER THE SOUTHWEST WILL KEEP THE AIRMASS WEAKLY UNSTABLE...AND WITH
PLENTY OF TROPICAL MOISTURE STILL IN PLACE...CHANCES FOR
THUNDERSTORMS WILL PERSIST OVER MUCH OF THE AREA WITH THE BEST
CHANCES IN THE EASTERN CWA. BEGINNING THURSDAY...THE UPPER LOW
SLOWLY LIFTS OUT TO THE NORTHEAST AS HIGH PRESSURE STARTS TO NOSE IN
FROM THE SOUTHWEST. THERE IS STILL SOME SPREAD AMONG THE ENSEMBLES
WITH RESPECT TO HOW QUICKLY THIS PATTERN CHANGE TAKES PLACE...BUT
CONFIDENCE IS INCREASING IN THE EXISTENCE OF THE PATTERN CHANGE. MOS
GUIDANCE NOW SHOW SURFACE DEWPOINTS IN THE 20S NORTHWEST AND
30S/40S SOUTHEAST BY SUNDAY...WHICH WOULD BE ABOUT A 30 DEGREE DROP
IN THE SOUTHEAST CWA FROM CONDITIONS OF THE PAST FEW WEEKS. AS THE
DRIER AIR MOVES IN...TEMPERATURES WILL RISE A FEW DEGREES...AND
COULD BE NEARING 100 DEGREES IN LAS VEGAS OVER THE WEEKEND.
&&
.VEF WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
AZ...NONE.
CA...NONE.
&&
$$
UPDATE...STACHELSKI
AVIATION...ADAIR
PREVIOUS...SALMEN/MORGAN
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
316 PM EDT MON SEP 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL PERSIST INTO MID WEEK AND THEN MOVE OFFSHORE.
A COLD FRONT IS EXPECTED TO CROSS THE AREA ON FRIDAY. HIGH
PRESSURE AND COOLER TEMPERATURES WILL FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM MONDAY...BEAUTIFUL AFTERNOON ONGOING ACROSS THE
CAROLINAS THANKS TO AN AREA OF HIGH PRESSURE CENTERED NEAR NEW
ENGLAND...RIDGING DOWN THE EAST COAST. TEMPS HAVE RISEN INTO THE
MID/UPR 80S...WHICH COMBINED WITH DEWPOINTS IN THE UPPER 60S HAS
SPAWNED SOME AGITATED CU...FROM WHICH A FEW ISOLATED SHOWERS HAVE
DEVELOPED. SHOWERS HAVE BEEN CONFINED TO THE WESTWARD MOVING SEA
BREEZE BOUNDARY...AND HAVE CONTINUED SCHC POP ALONG THIS BOUNDARY
FOR A FEW MORE HOURS BEFORE LOSS OF DIURNAL HEATING CAUSES ANY
CONVECTION TO CEASE. AS EXPECTED...NO LIGHTNING HAS DEVELOPED DUE TO
OVERALL WEAK UPDRAFTS BEING CAPPED BY A BULGING THERMAL INVERSION
AROUND 750MB NOTED ON RUC PROXIMITY SOUNDINGS (IN RESPONSE TO
MID-LEVEL RIDGING EXPANDING TO THE WEST)...AND HAVE KEPT RW- AS THE
WX TYPE THROUGH TONIGHT.
CLOUD COVER AND SHOWERS WILL DISSIPATE QUICKLY AFTER
NIGHTFALL...ALLOWING FOR VERY GOOD RADIATIONAL COOLING TONIGHT...AND
TEMPS WILL FALL RAPIDLY AFTER DARK. AS TEMPS FALL TONIGHT...CONCERN
BECOMES HOW COOL WILL THE AREA GET...AND WHAT FOG POTENTIAL EXISTS.
WITH QUICKLY FALLING TEMPS BENEATH THE DRY COLUMN...AND WINDS LIKELY
DECOUPLING...HAVE SHOWN SOME RADIATIONAL COOLING EFFECT IN THE MIN-T
FORECAST AND HAVE UNDERCUT MOS NUMBERS TONIGHT...WITH LOW-TO-MID 60S
EXPECTED. SOME TEMPS NEAR 60 ARE POSSIBLE IN THE TYPICALLY COOLER
LOCATIONS.
AS TEMPS FALL TO THESE VALUES TONIGHT...THEY WILL EXCEED THE
CROSSOVER TEMPS...A SIGNAL NORMALLY ASSOCIATED WITH FOG POTENTIAL.
AT THE SAME TIME...RUC AND NAM BUFR SOUNDINGS SHOW FAVORABLE
LOW-LEVEL HYDROLAPSE RATES FOR FOG DEVELOPMENT...ESPECIALLY INLAND
FROM THE COAST. HAVE ADDED PATCHY/AREAS OF FOG INLAND...WHERE FOG IS
MORE LIKELY. THE COAST MAY EXPERIENCE SOME FOG AS WELL...BUT IT WILL
NOT BE AS WIDESPREAD OR DENSE AS WHAT IS EXPECTED ACROSS THE
CENTRAL/WESTERN PORTIONS OF THE CWA.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...HIGH PRESSURE ALOFT WILL REMAIN IN PLACE ON
TUESDAY. AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL BE CENTERED
SOUTH OF THE CANADIAN MARITIMES AND RIDGE SW AND ALL THE WAY BACK
ACROSS THE EASTERN CAROLINAS. ON WED...THE SURFACE RIDGE WILL
BEGIN TO WEAKEN ACROSS THE SOUTHEAST UNITED STATES. THE LARGE
AREA OF HIGH PRESSURE ALOFT WILL SPLIT...TO OUR W AND TO OUR E.
THIS WILL ALLOW A TROUGH TO EVENTUALLY DIG ACROSS THE EASTERN
THIRD OF THE NATION LATE WEEK.
THE PERIOD LOOKS LIKE IT WILL BE DRY AS SUBSIDENCE AND DRY AIR...
ESPECIALLY IN THE MID LEVELS...DOMINATE. DO EXPECT SCATTERED TO
BRIEFLY BROKEN CUMULUS TO BUILD UP EACH AFTERNOON...BUT THIS
MOISTURE WILL BE CAPPED BELOW 10 KFT...KEEPING ANY BUILDUPS RATHER
SHALLOW. DAYTIME TEMPS WILL BE SLIGHTLY ABOVE NORMAL...COMMONLY IN
THE UPPER 80S TO LOWER 90S. THE SEABREEZE IS EXPECTED TO MAKE
GOOD INLAND PROGRESS GIVEN THE DEEP SYNOPTIC EASTERLY FLOW. THIS
WILL REDUCE HIGHS ALONG AND NEAR THE COAST BY ABOUT A CATEGORY AS
COMPARED TO LOCATIONS MUCH FURTHER INLAND. LOW TEMPS WILL BE
RATHER TYPICAL FOR MID SEPTEMBER...UPPER 60S AND LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 3 PM MONDAY...A RELATIVELY FAST MOVING/PROGRESSIVE TROUGH
WILL BE THE MAIN FEATURE FOR THE EXTENDED PERIOD OF THE FORECAST.
MEDIUM RANGE GUIDANCE HAS INCREASED THE TIMING FOR THE ASSOCIATED
FRONT WHICH NOW APPEARS TO MOVE ACROSS THE AREA FRIDAY MORNING.
THE LATEST UPDATE INCLUDES AN INCREASE OF POPS FOR THE THURSDAY
NIGHT/FRIDAY MORNING TIME PERIOD WITH A SLIGHT DOWNTREND FOR
FRIDAY`S POPS. IT APPEARS GUIDANCE IS ALSO CONVERGING ON A
SOLUTION OF A MORE SOUTHERN EXTENT OF THE FRONT FOR THE WEEKEND
INTO EARLY NEXT WEEK...SETTING UP A COOL AND DRY WEEKEND. DO NOT
EXPECT IDEAL RADIATIONAL CONDITIONS FOR ANY OVERNIGHT PERIOD BUT
SUNDAY MORNING APPEARS TO BE THE COOLEST WITH THE LIGHTEST WINDS.
WE HAVE LOWS IN THE LOWER 50S EXTREME NORTHWESTERN AREAS WITH NEAR
60 ALONG THE COAST. MOST HIGHS WILL BE IN THE UPPER 70S TO LOWER
80S FOR THE WEEKEND.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...VFR CONDITIONS WILL PREVAIL THIS AFTN WITH SOUTHEAST
WINDS AOB 10 KTS. DRY AIR ALOFT WILL INHIBIT MUCH CONVECTIVE
ACTIVITY TODAY...BUT ANY SHOWER ACTIVITY DOES NOT EVEN WARRANT A
VCSH MENTION WITHIN TAF. CLOUD COVER WILL BE COMPRISED OF SCT TO AT
TIMES BKN CU...BUT AT VFR HEIGHTS. CLEAR SKIES AND CALM/LIGHT WINDS
OVERNIGHT WILL BE CONDUCIVE FOR FOG EARLY TUESDAY...ESPECIALLY
INLAND. FCST SOUNDINGS AND GUIDANCE SUPPORT MVFR/TEMPO IFR VSBYS AT
KFLO/KLBT BETWEEN 09-12Z. DENSE FOG SEEMS LESS LIKELY ALONG THE
COAST...BUT TEMPO MVFR VSBYS ARE CERTAINLY POSSIBLE AROUND DAYBREAK.
ONCE THE FOG DISSIPATES...EXPECT VFR DURING THE DAY SATURDAY WITH
NORTHEAST WINDS 5-8 KTS.
EXTENDED OUTLOOK...EARLY MORNING MVFR/IFR VSBYS POSSIBLE THROUGH
THURSDAY...MOST LIKELY AT KFLO/KLBT. CHANCE OF SHOWERS/T-STORMS ON
FRIDAY ASSOCIATED WITH A COLD FRONT. OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM MONDAY...HIGH PRESSURE CENTERED ACROSS NEW ENGLAND IS
RIDGING DOWN THE COAST TODAY...WHICH HAS KEPT A WEAK PRESSURE
GRADIENT ACROSS THE WATERS. WINDS HAVE BEEN QUITE LIGHT IN RESPONSE
TO THIS GRADIENT...10 KTS OR LESS AT THE LOCAL BUOYS...AND THESE
SPEEDS WILL PERSIST TONIGHT EVEN AS DIRECTION BACKS MORE TO THE NE.
THE SEA SPECTRUM WILL REMAIN COMPRISED OF A LOW-AMPLITUDE E/NE WIND
CHOP AND A 2 FT SE SWELL...CREATING WAVE HEIGHTS OF 2-3 FT THROUGH
TONIGHT...BUT ONLY AROUND 1-2 FT NEAR SHORE OF BRUNSWICK COUNTY DUE
TO WAVE SHADOWING.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 PM MONDAY...HIGH PRESSURE WILL BE CENTERED WELL N OF THE
WATERS THROUGH THE PERIOD. WINDS WILL STILL BE FROM THE NE ON
TUE...VEERING SLIGHTLY TO ENE OR E TUE AFTERNOON AND EVE AND THEN
BACK TO A MORE NE DIRECTION OVERNIGHT TUE. NE WINDS WED MORNING
WILL VEER TO E OR ESE DURING THE DAY...BECOMING LIGHT AND VARIABLE
WED NIGHT. THE GRADIENT WILL BE TIGHTEST ON TUE...SUSTAINED WIND
SPEEDS UP TO 15 KT. THEREAFTER...WINDS WILL BE 10 KT OR LESS. WIND
SPEEDS WILL BE COMPARATIVELY HIGHER ACROSS THE NEAR SHORE WATERS
EACH AFTERNOON DUE TO SEABREEZE INFLUENCES. SEAS WILL BE 2 TO 3
FT...BUT THERE WILL BE SOME 4 FT SEAS TUE AFTERNOON WHEN THE
GRADIENT IS EXPECTED TO BE TIGHTEST.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 3 PM MONDAY...THE MAIN FEATURE WILL BE THE WIND SHIFT
ASSOCIATED WITH THE FRONT MOVING ACROSS THE WATERS FRIDAY MORNING.
WINDS WILL SHIFT FROM A MODEST PRE-FRONTAL SOUTHWESTERLY FLOW OF
10-15 KNOTS...MOSTLY HOVERING AROUND THE LOWER END OF THE RANGE TO
NORTH/NORTHEAST BY MIDDAY FRIDAY. SPEEDS WILL INCREASE TO REACH A
MAX OF 15-20 KNOTS EARLY SATURDAY. THE NORTHEASTERLY FLOW WILL BE
RELATIVELY STABLE AT 15-20 KNOTS FOR THE REMAINDER OF SATURDAY BUT
SPEEDS MAY DIMINISH TOWARD THE LOWER END OF THE RANGE. SIGNIFICANT
SEAS WILL INCREASE FROM 1-2 FEET EARLY TO 2-4 FEET BY THE END OF THE
PERIOD.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...BJR/JDW
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
145 PM EDT MON SEP 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND OVER THE AREA FROM THE NORTHEAST THROUGH
MIDWEEK. A COLD FRONT WILL MOVE THROUGH THE AREA EARLY FRIDAY. COOL
HIGH PRESSURE WILL BE OVER THE AREA FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 130 PM MONDAY...DROPPED POPS OVER SRN COASTAL SECTIONS AS
ACTIVITY JUST OFFSHORE HAS DISSIPATED. NO OTHER CHANGES.
/PREVIOUS DISCUSSION/
AS OF 645 AM MONDAY...COLD FRONT CONTINUES TO MAKE SLOW PROGRESS
INTO NORTHEASTERN NORTH CAROLINA AND SHOULD BE NEAR OR JUST SOUTH
OF OUR COAST BY 12Z TO 14Z THIS MORNING WITH WINDS BECOMING NE
THEN GRADUALLY E LATER IN THE DAY AS HIGH PRESSURE DRIFTS
OFFSHORE. SATELLITE IMAGERY SHOWING LOW CLOUDS BEHIND THE FRONT
OVER VIRGINIA BUT FEEL SKIES WILL BE PARTLY CLOUDY OVER OUR
REGION ALLOWING TEMPERATURES TO APPROACH FORECAST MAX TEMPS IN THE
MID TO UPPER 80S IN MOST AREAS. THE 3 KM HRRR AND 4 KM WRF STILL
SHOW SOME ISOLATED SHOWERS ALONG THE SEA BREEZE IN THE AFTERNOON
BUT WITH LARGE SCALE SUBSIDENCE AND STRONG NVA OVER EASTERN
NC...WILL CONTINUE TO LEAVE POPS OUT OF THE FORECAST FOR TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 340 AM MONDAY...THE LOW-LEVEL FLOW TONIGHT WILL BECOME LIGHT
AND ONSHORE. THIS WILL INCREASE BOUNDARY LAYER MOISTURE AND THERE
WILL AGAIN BE A GOOD LIKELYHOOD OF SOME LOWER STRATUS AND FOG
TOWARD MORNING. MINIMUM TEMPERATURES WILL BE FAIRLY SIMILAR TO
THIS MORNING WITH LOWS IN THE 66 TO 72 RANGE IN MOST AREAS.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 330 AM MON...THE LONG TERM PERIOD WILL FEATURE DRY AND WARM
WEATHER THROUGH THURSDAY...FOLLOWED BY A STRONG COLD FRONTAL
PASSAGE AND INCREASING PRECIP CHANCES THURSDAY NIGHT INTO
FRIDAY...THEN MUCH DRIER AND COOLER WEATHER FOR NEXT WEEKEND.
TEMPS WILL EDGE ABOVE CLIMO DURING THE MID WEEK TIME PERIOD WHILE
CONDITIONS REMAIN DRY WITH WESTERN ATLANTIC RIDGE CONTINUING TO
DOMINATE THE AREA. DEWPOINTS WILL BE ON THE INCREASE AS WELL WITH
TEMPS EDGING UPWARDS DURING THE OVERNIGHT PERIOD...THOUGH LOWS WILL
REMAIN NEAR CLIMO FOR EARLY SEPTEMBER. MED/LONG RANGE MODELS
CONVERGING ON STRONG SHORTWAVE TROUGH/SFC COLD FRONT TO AFFECT THE
AREA BEGINNING THURSDAY NIGHT. SW FLOW WILL INC ON THUR WITH TEMPS
REACHING INTO THE LOW 90S WITH TD`S INTO THE LOW 70S. ANY PRECIP
WILL REMAIN WELL WEST OF THE AREA THUR AFTERNOON WITH UPPER SUPPORT
IN THE APPALACHIANS. MODELS HAVE COME IN JUST A BIT FASTER WITH
FRONTAL PASSAGE...DURING THE DAY FRIDAY...THOUGH LAST SEVERAL RUNS
OF ECMWF HAVE COME IN DRIER THAN THE GFS WITH BULK OF UPPER SUPPORT
SHUNTING NORTH OF NC THROUGH THE MID ATLANTIC REGION. HAVE EDGED
POPS DOWNWARD TO 30-40 PERCENT TO REFLECT THE POSSIBLE DRIER FRONTAL
PASSAGE...AND MAY HAVE TO DECREASE FURTHER IF THIS TREND CONTINUES.
STRONG COOL AND DRY HIGH PRES WILL BUILD INTO THE AREA FROM THE NW
NEXT WEEKEND WITH TEMPS EXPECTED BELOW CLIMO ALONG WITH MUCH LOWER
RELATIVE HUMIDITY VALS.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH 18Z TUESDAY/...
AS OF 130 PM MONDAY...VFR CONDITIONS WILL PREVAIL THROUGH EVENING
WITH SOME FAIR WX CU THIS AFTN. IFR TO LIFR VSBYS LIKELY AGAIN LATE
TONIGHT ALL TAF SITES WITH ALL MODEL GDNC SUPPORTING FOG
DEVELOPMENT. CONDITIONS IMPROVING TO FAIR WX VFR 13Z-14Z TUESDAY.
LONG TERM /TUE THROUGH FRI/...
AS OF 330 AM MON...MAINLY VFR CONDITIONS THROUGH THE LONG TERM
PERIOD...WITH THE EXCEPTION OF LATE NIGHT/EARLY AM RADIATION FOG.
HIGH PRES WILL DOMINATE THROUGH THURSDAY...FOLLOWED BY A STRONG
COLD FRONT PUSHING THROUGH LATE THURSDAY NIGHT INTO FRIDAY. A
SMALL CHANCE OF PRECIP WILL ACCOMPANY THE FRONTAL PASSAGE. STRONG
DRY HIGH PRES WILL BUILD IN FOR NEXT WEEKEND.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 130 PM MONDAY...DECREASED SHOWER COVERAGE TO ISOLATED FOR SRN
WATERS REST OF AFTN. NO OTHER SIGNIFICANT CHANGES TO FCST.
/PREVIOUS DISCUSSION/
AS OF 655 AM MONDAY...WINDS HAVE BECOME NE OVER THE FAR NORTHERN
WATERS AND SHOULD GRADUALLY VEER FROM SW/W AROUND TO N/NE OVER THE
NEXT 3 OR 4 HOURS OVER ALL WATERS AND SOUNDS. GIVEN SOME GUSTS
INTO THE HIGH TEENS OVER THE HAMPTON ROADS AREA OF VIRGINIA
FOLLOWING THE FRONTAL PASSAGE...HAVE BUMPED WINDS INTO THE 10 TO
15 KNOT RANGE OVER ALL WATERS AND WOULD NOT BE SURPRISED TO SEE A
FEW GUSTS APPROACHING 20 KNOTS THIS MORNING BEFORE SUBSIDING THIS
AFTERNOON AS THE HIGH MOVES OFFSHORE. SEAS SHOULD REMAIN IN THE 2
TO 4 FOOT RANGE. LOCAL NWPS MODEL SHOWS SEAS BUILDING TO AROUND 4
FEET OVER THE CENTRAL AND NORTHERN WATERS TONIGHT AS THE HIGH
MOVES OFFSHORE AND MORE SE SWELL ENERGY DEVELOPS.
LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 330 AM MON...WINDS WILL GRADUALLY VEER TO THE E AND SE TUE
INTO WED WITH SPEEDS 10 KT OR LESS AS THE SFC RIDGE EXTENDS OVER
AREA FROM E-NE. FLOW WILL INCREASE A BIT FROM THE SW LATE THU AHEAD
OF THE NEXT APPROACHING COLD FRONT. POTENTIAL FOR SCA CONDITIONS FRI
INTO THE WEEKEND AS STRONG HIGH PRES BUILDS IN FROM THE NW WITH COLD
AIR ADVECTION OVER THE WATERS AND TIGHTENING NE GRADIENT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JBM
NEAR TERM...JBM/CTC
SHORT TERM...CTC
LONG TERM...TL
AVIATION...JBM/TL
MARINE...CTC/TL/JBM
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1005 AM EDT MON SEP 9 2013
.SYNOPSIS...
A WEAK FRONT WILL MOVE OFFSHORE THIS MORNING. HIGH PRESSURE WILL
BUILD IN FROM THE NORTH AND EAST THROUGH MIDWEEK. ANOTHER STRONGER
COLD FRONT WILL MOVE THROUGH THE AREA EARLY FRIDAY. COOL HIGH
PRESSURE WILL BE OVER THE AREA THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 945 AM MONDAY...ADDED 20/30 POPS S COAST INTO EARLY
MORNING...WITH CURRENT SCT SHOWER ACTIVITY JUST OFFSHORE AFFECTING
CAPE LOOKOUT VICINITY NEXT FEW HOURS. MINOR ADJUSTMENTS TO TEMPS AND
SKY COVER. WINDS HAVE SHIFTED TO NE ALL ZONES WITH PASSAGE OF
LEADING EDGE OF WEAK SFC FRONT...BUT NO SIGNIFICANT CAA SURGE BEHIND
IT. ONSHORE FLOW WILL KEEP NRN OBX MAX TEMPS BELOW 80 BUT STILL
EXPECT MID TO UPR 80S INLAND. MESO MODELS INDICATE ISOLATED SHOWERS
PSBL INLAND THIS AFTN BUT DRY CONDITIONS ALOFT EXPECTED TO LIMIT
DEVELOPMENT...SO KEPT DRY FCST.
/PREVIOUS DISCUSSION/
AS OF 645 AM MONDAY...COLD FRONT CONTINUES TO MAKE SLOW PROGRESS
INTO NORTHEASTERN NORTH CAROLINA AND SHOULD BE NEAR OR JUST SOUTH
OF OUR COAST BY 12Z TO 14Z THIS MORNING WITH WINDS BECOMING NE
THEN GRADUALLY E LATER IN THE DAY AS HIGH PRESSURE DRIFTS
OFFSHORE. SATELLITE IMAGERY SHOWING LOW CLOUDS BEHIND THE FRONT
OVER VIRGINIA BUT FEEL SKIES WILL BE PARTLY CLOUDY OVER OUR
REGION ALLOWING TEMPERATURES TO APPROACH FORECAST MAX TEMPS IN THE
MID TO UPPER 80S IN MOST AREAS. THE 3 KM HRRR AND 4 KM WRF STILL
SHOW SOME ISOLATED SHOWERS ALONG THE SEA BREEZE IN THE AFTERNOON
BUT WITH LARGE SCALE SUBSIDENCE AND STRONG NVA OVER EASTERN
NC...WILL CONTINUE TO LEAVE POPS OUT OF THE FORECAST FOR TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 340 AM MONDAY...THE LOW-LEVEL FLOW TONIGHT WILL BECOME LIGHT
AND ONSHORE. THIS WILL INCREASE BOUNDARY LAYER MOISTURE AND THERE
WILL AGAIN BE A GOOD LIKELYHOOD OF SOME LOWER STRATUS AND FOG
TOWARD MORNING. MINIMUM TEMPERATURES WILL BE FAIRLY SIMILAR TO
THIS MORNING WITH LOWS IN THE 66 TO 72 RANGE IN MOST AREAS.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 330 AM MON...THE LONG TERM PERIOD WILL FEATURE DRY AND WARM
WEATHER THROUGH THURSDAY...FOLLOWED BY A STRONG COLD FRONTAL
PASSAGE AND INCREASING PRECIP CHANCES THURSDAY NIGHT INTO
FRIDAY...THEN MUCH DRIER AND COOLER WEATHER FOR NEXT WEEKEND.
TEMPS WILL EDGE ABOVE CLIMO DURING THE MID WEEK TIME PERIOD WHILE
CONDITIONS REMAIN DRY WITH WESTERN ATLANTIC RIDGE CONTINUING TO
DOMINATE THE AREA. DEWPOINTS WILL BE ON THE INCREASE AS WELL WITH
TEMPS EDGING UPWARDS DURING THE OVERNIGHT PERIOD...THOUGH LOWS WILL
REMAIN NEAR CLIMO FOR EARLY SEPTEMBER. MED/LONG RANGE MODELS
CONVERGING ON STRONG SHORTWAVE TROUGH/SFC COLD FRONT TO AFFECT THE
AREA BEGINNING THURSDAY NIGHT. SW FLOW WILL INC ON THUR WITH TEMPS
REACHING INTO THE LOW 90S WITH TD`S INTO THE LOW 70S. ANY PRECIP
WILL REMAIN WELL WEST OF THE AREA THUR AFTERNOON WITH UPPER SUPPORT
IN THE APPALACHIANS. MODELS HAVE COME IN JUST A BIT FASTER WITH
FRONTAL PASSAGE...DURING THE DAY FRIDAY...THOUGH LAST SEVERAL RUNS
OF ECMWF HAVE COME IN DRIER THAN THE GFS WITH BULK OF UPPER SUPPORT
SHUNTING NORTH OF NC THROUGH THE MID ATLANTIC REGION. HAVE EDGED
POPS DOWNWARD TO 30-40 PERCENT TO REFLECT THE POSSIBLE DRIER FRONTAL
PASSAGE...AND MAY HAVE TO DECREASE FURTHER IF THIS TREND CONTINUES.
STRONG COOL AND DRY HIGH PRES WILL BUILD INTO THE AREA FROM THE NW
NEXT WEEKEND WITH TEMPS EXPECTED BELOW CLIMO ALONG WITH MUCH LOWER
RELATIVE HUMIDITY VALS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 650 AM MONDAY...OCCASIONAL STRATUS AND FOG HAS BEEN REPORTED
AT THE TAF SITES THIS MORNING WITH KPGV BRIEFLY DROPPING TO LIFR.
AS THE COLD FRONT APPROACHES FROM THE VA/NC BORDER...EXPECT BETTER
MIXING AND ANY STRATUS AND FOG TO GRADUALLY DISSIPATE BY 12Z TO
14Z. WILL LIKELY SEE SOME SCATTERED TO BROKEN CUMULUS THROUGH
EARLY AFTERNOON...THEN CLEARING SKIES. MODEL GUIDANCE AGAIN
INDICATES LOW STRATUS AND FOG AGAIN TONIGHT AND WILL TREND THE
FORECAST THAT WAY ONCE AGAIN.
LONG TERM /TUE THROUGH SAT/...
AS OF 330 AM MON...MAINLY VFR CONDITIONS THROUGH THE LONG TERM
PERIOD...WITH THE EXCEPTION OF LATE NIGHT/EARLY AM RADIATION FOG.
HIGH PRES WILL DOMINATE THROUGH THURSDAY...FOLLOWED BY A STRONG
COLD FRONT PUSHING THROUGH LATE THURSDAY NIGHT INTO FRIDAY. A
SMALL CHANCE OF PRECIP WILL ACCOMPANY THE FRONTAL PASSAGE. STRONG
DRY HIGH PRES WILL BUILD IN FOR NEXT WEEKEND.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 945 AM MONDAY...INCREASED POPS TO 30% AND ADDED MENTION OF
ISOLD TO SCT SHOWERS FOR SRN WATERS INTO EARLY AFTN...PER NEAR TERM
DISCUSSION WITH ONGOING ACTIVITY NEAR CAPE LOOKOUT. NO SIGNIFICANT
CHANGES TO WINDS/SEAS...WEAK SFC FRONT HAS PUSHED S OF AREA AND CAA
SURGE WILL GENERALLY REMAIN 15 KT OR BELOW.
/PREVIOUS DISCUSSION/
AS OF 655 AM MONDAY...WINDS HAVE BECOME NE OVER THE FAR NORTHERN
WATERS AND SHOULD GRADUALLY VEER FROM SW/W AROUND TO N/NE OVER THE
NEXT 3 OR 4 HOURS OVER ALL WATERS AND SOUNDS. GIVEN SOME GUSTS
INTO THE HIGH TEENS OVER THE HAMPTON ROADS AREA OF VIRGINIA
FOLLOWING THE FRONTAL PASSAGE...HAVE BUMPED WINDS INTO THE 10 TO
15 KNOT RANGE OVER ALL WATERS AND WOULD NOT BE SURPRISED TO SEE A
FEW GUSTS APPROACHING 20 KNOTS THIS MORNING BEFORE SUBSIDING THIS
AFTERNOON AS THE HIGH MOVES OFFSHORE. SEAS SHOULD REMAIN IN THE 2
TO 4 FOOT RANGE. LOCAL NWPS MODEL SHOWS SEAS BUILDING TO AROUND 4
FEET OVER THE CENTRAL AND NORTHERN WATERS TONIGHT AS THE HIGH
MOVES OFFSHORE AND MORE SE SWELL ENERGY DEVELOPS.
LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 330 AM MON...WINDS WILL GRADUALLY VEER TO THE E AND SE TUE
INTO WED WITH SPEEDS 10 KT OR LESS AS THE SFC RIDGE EXTENDS OVER
AREA FROM E-NE. FLOW WILL INCREASE A BIT FROM THE SW LATE THU AHEAD
OF THE NEXT APPROACHING COLD FRONT. POTENTIAL FOR SCA CONDITIONS FRI
INTO THE WEEKEND AS STRONG HIGH PRES BUILDS IN FROM THE NW WITH COLD
AIR ADVECTION OVER THE WATERS AND TIGHTENING NE GRADIENT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CTC
NEAR TERM...JBM/CTC
SHORT TERM...CTC
LONG TERM...TL
AVIATION...CTC/TL
MARINE...CTC/TL/JBM
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
655 AM EDT MON SEP 9 2013
.SYNOPSIS...
A WEAK FRONT WILL MOVE OFFSHORE THIS MORNING. HIGH PRESSURE WILL
BUILD IN FROM THE NORTH AND EAST THROUGH MIDWEEK. ANOTHER STRONGER
COLD FRONT WILL MOVE THROUGH THE AREA EARLY FRIDAY. COOL HIGH PRESSURE
WILL BE OVER THE AREA THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 645 AM MONDAY...COLD FRONT CONTINUES TO MAKE SLOW PROGRESS
INTO NORTHEASTERN NORTH CAROLINA AND SHOULD BE NEAR OR JUST SOUTH
OF OUR COAST BY 12Z TO 14Z THIS MORNING WITH WINDS BECOMING NE
THEN GRADUALLY E LATER IN THE DAY AS HIGH PRESSURE DRIFTS
OFFSHORE. SATELLITE IMAGERY SHOWING LOW CLOUDS BEHIND THE FRONT
OVER VIRGINIA BUT FEEL SKIES WILL BE PARTLY CLOUDY OVER OUR
REGION ALLOWING TEMPERATURES TO APPROACH FORECAST MAX TEMPS IN THE
MID TO UPPER 80S IN MOST AREAS. THE 3 KM HRRR AND 4 KM WRF STILL
SHOW SOME ISOLATED SHOWERS ALONG THE SEA BREEZE IN THE AFTERNOON
BUT WITH LARGE SCALE SUBSIDENCE AND STRONG NVA OVER EASTERN
NC...WILL CONTINUE TO LEAVE POPS OUT OF THE FORECAST FOR TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
AS OF 340 AM MONDAY...THE LOW-LEVEL FLOW TONIGHT WILL BECOME LIGHT
AND ONSHORE. THIS WILL INCREASE BOUNDARY LAYER MOISTURE AND THERE
WILL AGAIN BE A GOOD LIKELYHOOD OF SOME LOWER STRATUS AND FOG
TOWARD MORNING. MINIMUM TEMPERATURES WILL BE FAIRLY SIMILAR TO
THIS MORNING WITH LOWS IN THE 66 TO 72 RANGE IN MOST AREAS.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 330 AM MON...THE LONG TERM PERIOD WILL FEATURE DRY AND WARM
WEATHER THROUGH THURSDAY...FOLLOWED BY A STRONG COLD FRONTAL
PASSAGE AND INCREASING PRECIP CHANCES THURSDAY NIGHT INTO
FRIDAY...THEN MUCH DRIER AND COOLER WEATHER FOR NEXT WEEKEND.
TEMPS WILL EDGE ABOVE CLIMO DURING THE MID WEEK TIME PERIOD WHILE
CONDITIONS REMAIN DRY WITH WESTERN ATLANTIC RIDGE CONTINUING TO
DOMINATE THE AREA. DEWPOINTS WILL BE ON THE INCREASE AS WELL WITH
TEMPS EDGING UPWARDS DURING THE OVERNIGHT PERIOD...THOUGH LOWS WILL
REMAIN NEAR CLIMO FOR EARLY SEPTEMBER. MED/LONG RANGE MODELS
CONVERGING ON STRONG SHORTWAVE TROUGH/SFC COLD FRONT TO AFFECT THE
AREA BEGINNING THURSDAY NIGHT. SW FLOW WILL INC ON THUR WITH TEMPS
REACHING INTO THE LOW 90S WITH TD`S INTO THE LOW 70S. ANY PRECIP
WILL REMAIN WELL WEST OF THE AREA THUR AFTERNOON WITH UPPER SUPPORT
IN THE APPALACHIANS. MODELS HAVE COME IN JUST A BIT FASTER WITH
FRONTAL PASSAGE...DURING THE DAY FRIDAY...THOUGH LAST SEVERAL RUNS
OF ECMWF HAVE COME IN DRIER THAN THE GFS WITH BULK OF UPPER SUPPORT
SHUNTING NORTH OF NC THROUGH THE MID ATLANTIC REGION. HAVE EDGED
POPS DOWNWARD TO 30-40 PERCENT TO REFLECT THE POSSIBLE DRIER FRONTAL
PASSAGE...AND MAY HAVE TO DECREASE FURTHER IF THIS TREND CONTINUES.
STRONG COOL AND DRY HIGH PRES WILL BUILD INTO THE AREA FROM THE NW
NEXT WEEKEND WITH TEMPS EXPECTED BELOW CLIMO ALONG WITH MUCH LOWER
RELATIVE HUMIDITY VALS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 650 AM MONDAY...OCCASIONAL STRATUS AND FOG HAS BEEN REPORTED
AT THE TAF SITES THIS MORNING WITH KPGV BRIEFLY DROPPING TO LIFR.
AS THE COLD FRONT APPROACHES FROM THE VA/NC BORDER...EXPECT BETTER
MIXING AND ANY STRATUS AND FOG TO GRADUALLY DISSIPATE BY 12Z TO
14Z. WILL LIKELY SEE SOME SCATTERED TO BROKEN CUMULUS THROUGH
EARLY AFTERNOON...THEN CLEARING SKIES. MODEL GUIDANCE AGAIN
INDICATES LOW STRATUS AND FOG AGAIN TONIGHT AND WILL TREND THE
FORECAST THAT WAY ONCE AGAIN.
LONG TERM /TUE THROUGH SAT/...
AS OF 330 AM MON...MAINLY VFR CONDITIONS THROUGH THE LONG TERM
PERIOD...WITH THE EXCEPTION OF LATE NIGHT/EARLY AM RADIATION FOG.
HIGH PRES WILL DOMINATE THROUGH THURSDAY...FOLLOWED BY A STRONG
COLD FRONT PUSHING THROUGH LATE THURSDAY NIGHT INTO FRIDAY. A
SMALL CHANCE OF PRECIP WILL ACCOMPANY THE FRONTAL PASSAGE. STRONG
DRY HIGH PRES WILL BUILD IN FOR NEXT WEEKEND.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 655 AM MONDAY...WINDS HAVE BECOME NE OVER THE FAR NORTHERN
WATERS AND SHOULD GRADUALLY VEER FROM SW/W AROUND TO N/NE OVER THE
NEXT 3 OR 4 HOURS OVER ALL WATERS AND SOUNDS. GIVEN SOME GUSTS
INTO THE HIGH TEENS OVER THE HAMPTON ROADS AREA OF VIRGINIA
FOLLOWING THE FRONTAL PASSAGE...HAVE BUMPED WINDS INTO THE 10 TO
15 KNOT RANGE OVER ALL WATERS AND WOULD NOT BE SURPRISED TO SEE A
FEW GUSTS APPROACHING 20 KNOTS THIS MORNING BEFORE SUBSIDING THIS
AFTERNOON AS THE HIGH MOVES OFFSHORE. SEAS SHOULD REMAIN IN THE 2
TO 4 FOOT RANGE. LOCAL NWPS MODEL SHOWS SEAS BUILDING TO AROUND 4
FEET OVER THE CENTRAL AND NORTHERN WATERS TONIGHT AS THE HIGH
MOVES OFFSHORE AND MORE SE SWELL ENERGY DEVELOPS.
LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 330 AM MON...WINDS WILL GRADUALLY VEER TO THE E AND SE TUE
INTO WED WITH SPEEDS 10 KT OR LESS AS THE SFC RIDGE EXTENDS OVER
AREA FROM E-NE. FLOW WILL INCREASE A BIT FROM THE SW LATE THU AHEAD
OF THE NEXT APPROACHING COLD FRONT. POTENTIAL FOR SCA CONDITIONS FRI
INTO THE WEEKEND AS STRONG HIGH PRES BUILDS IN FROM THE NW WITH COLD
AIR ADVECTION OVER THE WATERS AND TIGHTENING NE GRADIENT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...TL
AVIATION...CTC/TL
MARINE...CTC/TL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
123 PM CDT MON SEP 9 2013
.UPDATE...
ISSUED AT 123 PM CDT MON SEP 9 2013
UPDATED MAINLY FOR CLEANING UP POPS AND SKY COVER. SHOWERS
CONTINUE TO MOVE OUT OF CENTRAL INTO EASTERN NORTH DAKOTA WITH A
DIMINISHING TREND. SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPING
IN NORTHEAST MONTANA ARE ABOUT TO MOVE INTO THE FAR NORTHWEST.
TEMPERATURES APPEAR IN LINE FOR AFTERNOON HIGHS.
UPDATE ISSUED AT 1017 AM CDT MON SEP 9 2013
UPDATE THIS MORNING DEALT MAINLY WITH ADJUSTING CLOUDS AND POPS TO
CURRENT RADAR AND SATELLITE IMAGERY. CLEARING OUT ACROSS THE
SOUTHWEST...BUT SHOWERS CONTINUE OVER THE NORTH CENTRAL ON THE
BACK SIDE OF THE SURFACE LOW OVER SOUTHEAST NORTH DAKOTA.
UPDATE ISSUED AT 644 AM CDT MON SEP 9 2013
THE LATEST RADAR TRENDS AND 3KM HRRR INDICATE DECREASING
PRECIPITATION INTENSITY ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
EVEN THOUGH COPIOUS AMOUNTS OF MOISTURE ARE OVER THE AREA...THE
ATMOSPHERE IS PRETTY WELL WORKED OVER FOR ANY STORMS TO GROW
UPSCALE THIS MORNING. AS A RESULT...DECIDED TO CANCEL THE FLASH
FLOOD WATCH ACROSS THE ENTIRE CWA THIS MORNING.
AN UPPER LEVEL LOW CURRENTLY SITUATED OVER NORTH CENTRAL MONTANA
IS FORECAST TO PIVOT INTO NORTHWESTERN NORTH DAKOTA LATER THIS
AFTERNOON. THIS COMBINED WITH INCREASING UPPER LEVEL DYNAMICS MAY
ALLOW THUNDERSTORMS TO DEVELOP AND BECOME SEVERE...MAINLY NORTH
OF I-94 LATER THIS AFTERNOON AND EVENING. THE DAY 1 SPC OUTLOOK
HAS NORTHERN NORTH DAKOTA IN A "SEE TEXT" CATEGORY AND A 5% CHANCE
OF DAMAGING WINDS AND HAIL. AS A RESULT...HIGHLIGHTED THIS THREAT
IN THE HWO. HOWEVER...KEPT IT OUT OF THE ZONES DUE TO ITS LOW
PROBABILITY.
THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 452 AM CDT MON SEP 9 2013
THE SEVERE THREAT HAS ENDED ACROSS THE JAMES RIVER BASIN. AS A
RESULT...CANCELLED THE SEVERE THUNDERSTORM WATCH FOR THE AFFECTED
AREAS. OTHERWISE...ONLY MODIFIED THE REMAINING WEATHER ELEMENTS
BASED ON CURRENT OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON SEP 9 2013
IN THE NEAR TERM...THE SEVERE WEATHER THREAT IS LIKELY OVER AS THE
BOW ECHO HAS PUSHED EAST OF THE FORECAST AREA. HEAVY RAIN THREAT
WILL PERSIST...MAINLY IN THE JAMES RIVER VALLEY THIS MORNING. SEE
HYDRO DISCUSSION BELOW FOR DETAILS. MUCH OF THE FORECAST AREA IS
MENTIONED IN THE SEE TEXT AREA OF THE SPC DAY 1 OUTLOOK. ISOLD
LARGE HAIL/WIND GUSTS NOT OUT OF THE QUESTION THIS
AFTERNOON/EVENING. WITH THE 500MB COLD POOL MOVING INTO THE NORTH
THIS AFTERNOON...WILL ALSO HAVE TO MONITOR FOR POTENTIAL
FUNNELS/BRIEF NON-SUPERCELL TORNADOES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON SEP 9 2013
QUIET WEATHER WILL CONTINUE FOR MUCH OF THE LONG TERM PERIOD. THE
MAIN WINDOW FOR THUNDERSTORM ACTIVITY WILL BE FRIDAY
NIGHT/SATURDAY. OTHERWISE...EXPECT MILDER TEMPS WITH HIGHS
GENERALLY IN THE 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 123 PM CDT MON SEP 9 2013
MVFR CEILINGS THIS AFTERNOON WILL SLOWLY LIFT THROUGH 23 UTC. THEN
VFR CEILINGS EXPECTED UNTIL AROUND 06Z AS AREAS OF MVFR CEILINGS
ARE EXPECTED TO DROP SOUTHEAST ACROSS THE AREA BEHIND THE UPPER
LEVEL LOW THAT TRACKS EAST ACROSS NORTHERN NORTH DAKOTA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...RK
LONG TERM...RK
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1017 AM CDT MON SEP 9 2013
.UPDATE...
ISSUED AT 1017 AM CDT MON SEP 9 2013
UPDATE THIS MORNING DEALT MAINLY WITH ADJUSTING CLOUDS AND POPS TO
CURRENT RADAR AND SATELLITE IMAGERY. CLEARING OUT ACROSS THE
SOUTHWEST...BUT SHOWERS CONTINUE OVER THE NORTH CENTRAL ON THE
BACK SIDE OF THE SURFACE LOW OVER SOUTHEAST NORTH DAKOTA.
UPDATE ISSUED AT 644 AM CDT MON SEP 9 2013
THE LATEST RADAR TRENDS AND 3KM HRRR INDICATE DECREASING
PRECIPITATION INTENSITY ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
EVEN THOUGH COPIOUS AMOUNTS OF MOISTURE ARE OVER THE AREA...THE
ATMOSPHERE IS PRETTY WELL WORKED OVER FOR ANY STORMS TO GROW
UPSCALE THIS MORNING. AS A RESULT...DECIDED TO CANCEL THE FLASH
FLOOD WATCH ACROSS THE ENTIRE CWA THIS MORNING.
AN UPPER LEVEL LOW CURRENTLY SITUATED OVER NORTH CENTRAL MONTANA
IS FORECAST TO PIVOT INTO NORTHWESTERN NORTH DAKOTA LATER THIS
AFTERNOON. THIS COMBINED WITH INCREASING UPPER LEVEL DYNAMICS MAY
ALLOW THUNDERSTORMS TO DEVELOP AND BECOME SEVERE...MAINLY NORTH
OF I-94 LATER THIS AFTERNOON AND EVENING. THE DAY 1 SPC OUTLOOK
HAS NORTHERN NORTH DAKOTA IN A "SEE TEXT" CATEGORY AND A 5% CHANCE
OF DAMAGING WINDS AND HAIL. AS A RESULT...HIGHLIGHTED THIS THREAT
IN THE HWO. HOWEVER...KEPT IT OUT OF THE ZONES DUE TO ITS LOW
PROBABILITY.
THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 452 AM CDT MON SEP 9 2013
THE SEVERE THREAT HAS ENDED ACROSS THE JAMES RIVER BASIN. AS A
RESULT...CANCELLED THE SEVERE THUNDERSTORM WATCH FOR THE AFFECTED
AREAS. OTHERWISE...ONLY MODIFIED THE REMAINING WEATHER ELEMENTS
BASED ON CURRENT OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON SEP 9 2013
IN THE NEAR TERM...THE SEVERE WEATHER THREAT IS LIKELY OVER AS THE
BOW ECHO HAS PUSHED EAST OF THE FORECAST AREA. HEAVY RAIN THREAT
WILL PERSIST...MAINLY IN THE JAMES RIVER VALLEY THIS MORNING. SEE
HYDRO DISCUSSION BELOW FOR DETAILS. MUCH OF THE FORECAST AREA IS
MENTIONED IN THE SEE TEXT AREA OF THE SPC DAY 1 OUTLOOK. ISOLD
LARGE HAIL/WIND GUSTS NOT OUT OF THE QUESTION THIS
AFTERNOON/EVENING. WITH THE 500MB COLD POOL MOVING INTO THE NORTH
THIS AFTERNOON...WILL ALSO HAVE TO MONITOR FOR POTENTIAL
FUNNELS/BRIEF NON-SUPERCELL TORNADOES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON SEP 9 2013
QUIET WEATHER WILL CONTINUE FOR MUCH OF THE LONG TERM PERIOD. THE
MAIN WINDOW FOR THUNDERSTORM ACTIVITY WILL BE FRIDAY
NIGHT/SATURDAY. OTHERWISE...EXPECT MILDER TEMPS WITH HIGHS
GENERALLY IN THE 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1017 AM CDT MON SEP 9 2013
AREAS MVFR CEILINGS AND VISIBILITIES OVER CENTRAL NORTH DAKOTA
THIS MORNING FROM KMOT AND KBIS EAST THROUGH KJMS. EXPECT THESE TO
CLEAR SLOWLY THROUGH EARLY AFTERNOON. LOWER CEILINGS AND
VISIBILITIES HAVE CLEARED AT KISN AND KDIK. AREAS MVFR CEILINGS
AND VISIBILITIES IN SHOWERS AND SCATTERED THUNDERSTORMS THIS
AFTERNOON FROM KISN TO KMOT AS UPPER LEVEL LOW TRACKS EAST ACROSS
THIS AREA. EXPECT VFR CONDITIONS THIS EVENING THROUGH 18Z TUESDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...RK
LONG TERM...RK
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
644 AM CDT MON SEP 9 2013
.UPDATE...
ISSUED AT 644 AM CDT MON SEP 9 2013
THE LATEST RADAR TRENDS AND 3KM HRRR INDICATE DECREASING
PRECIPITATION INTENSITY ACROSS WESTERN AND CENTRAL NORTH DAKOTA.
EVEN THOUGH COPIOUS AMOUNTS OF MOISTURE ARE OVER THE AREA...THE
ATMOSPHERE IS PRETTY WELL WORKED OVER FOR ANY STORMS TO GROW
UPSCALE THIS MORNING. AS A RESULT...DECIDED TO CANCEL THE FLASH
FLOOD WATCH ACROSS THE ENTIRE CWA THIS MORNING.
AN UPPER LEVEL LOW CURRENTLY SITUATED OVER NORTH CENTRAL MONTANA
IS FORECAST TO PIVOT INTO NORTHWESTERN NORTH DAKOTA LATER THIS
AFTERNOON. THIS COMBINED WITH INCREASING UPPER LEVEL DYNAMICS MAY
ALLOW THUNDERSTORMS TO DEVELOP AND BECOME SEVERE...MAINLY NORTH
OF I-94 LATER THIS AFTERNOON AND EVENING. THE DAY 1 SPC OUTLOOK
HAS NORTHERN NORTH DAKOTA IN A "SEE TEXT" CATEGORY AND A 5% CHANCE
OF DAMAGING WINDS AND HAIL. AS A RESULT...HIGHLIGHTED THIS THREAT
IN THE HWO. HOWEVER...KEPT IT OUT OF THE ZONES DUE TO ITS LOW
PROBABILITY.
THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 452 AM CDT MON SEP 9 2013
THE SEVERE THREAT HAS ENDED ACROSS THE JAMES RIVER BASIN. AS A
RESULT...CANCELLED THE SEVERE THUNDERSTORM WATCH FOR THE AFFECTED
AREAS. OTHERWISE...ONLY MODIFIED THE REMAINING WEATHER ELEMENTS
BASED ON CURRENT OBS/TRENDS. THE UPDATED PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON SEP 9 2013
IN THE NEAR TERM...THE SEVERE WEATHER THREAT IS LIKELY OVER AS THE
BOW ECHO HAS PUSHED EAST OF THE FORECAST AREA. HEAVY RAIN THREAT
WILL PERSIST...MAINLY IN THE JAMES RIVER VALLEY THIS MORNING. SEE
HYDRO DISCUSSION BELOW FOR DETAILS. MUCH OF THE FORECAST AREA IS
MENTIONED IN THE SEE TEXT AREA OF THE SPC DAY 1 OUTLOOK. ISOLD
LARGE HAIL/WIND GUSTS NOT OUT OF THE QUESTION THIS
AFTERNOON/EVENING. WITH THE 500MB COLD POOL MOVING INTO THE NORTH
THIS AFTERNOON...WILL ALSO HAVE TO MONITOR FOR POTENTIAL
FUNNELS/BRIEF NON-SUPERCELL TORNADOES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON SEP 9 2013
QUIET WEATHER WILL CONTINUE FOR MUCH OF THE LONG TERM PERIOD. THE
MAIN WINDOW FOR THUNDERSTORM ACTIVITY WILL BE FRIDAY
NIGHT/SATURDAY. OTHERWISE...EXPECT MILDER TEMPS WITH HIGHS
GENERALLY IN THE 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 644 AM CDT MON SEP 9 2013
SHOWERS AND ISOLATED THUNDERSTORMS CONTINUE AT ALL TERMINALS EARLY
THIS MORNING...ALONG WITH AREAS OF LIFR-VLIFR CIGS. CIGS ARE
FORECAST TO SCATTER OUT/LIFT 14-17Z...BUT MAY SEE SOME LOWER STRATUS
LINGER AT KJMS INTO EARLY THIS AFTERNOON. INCREASING AFTERNOON
CLOUDS 20-21Z THROUGH 02-04Z THIS EVENING MOST LOCATIONS...WITH
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS REDEVELOPING MAINLY AT
KISN-KMOT-KJMS. HIGH LOW LEVEL MOISTURE FROM RECENT RAINS COUPLED
WITH PARTIALLY CLEARING SKIES AND DECREASING WINDS MAY RESULT IN
FOG/STRATUS DEVELOPMENT LATER MONDAY NIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...RK
LONG TERM...RK
AVIATION...NH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
140 PM EDT MON SEP 9 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES
WILL MOVE OFF THE NEW ENGLAND COAST TODAY. THIS WILL ALLOW A WARM
FRONT TO LIFT NORTHEAST ACROSS THE LOCAL AREA. AN AREA OF LOW
PRESSURE WILL PASS WELL TO THE NORTH ON WEDNESDAY AND DRAG A COLD
FRONT ACROSS THE REGION ON WEDNESDAY NIGHT. HIGH PRESSURE WILL
RETURN FOR THE END OF THE WORKWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
TWEAKED TEMPS UP A LITTLE IN THE EAST...OTHERWISE FORECAST LOOKS
GOOD.
ORIGINAL...QUITE A BIT OF SHOWER AND THUNDERSTORM ACTIVITY OVER SW LOWER
MICHIGAN. THIS ACTIVITY HAS FORMED ALONG A WARM FRONT THAT WILL
LIFT NE ACROSS THE LOCAL AREA TODAY. ALL OF THE NEW
GUIDANCE...INCLUDING THE HRRR AND CONVECTIVE SREF SHOW AT LEAST
SCATTERED PRECIP. HAVE BUMPED PRECIP CHANCES UP ALL AREAS TO
AROUND 40 PERCENT. MAY EVENTUALLY HAVE TO BUMP IT EVER FURTHER
DEPENDING ON WHAT THE ACTIVITY OVER MI DOES. DEWPOINTS ARE ALREADY ON
THE WAY UP AND EXPECTING MID 60S BY EARLY EVENING. THERE SHOULD
BE A LOT OF CLOUDINESS TODAY BUT TEMPS WILL STILL MAKE THE 80S
OVER ALL BUT THE EASTERN END OF THE AREA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
THE WARM FRONT WILL MOVE NORTH OF LAKE ERIE THIS EVENING AND THAT
SHOULD END THE THREAT FOR ADDITIONAL PRECIP. WILL START THE
TONIGHT PERIOD OUT WITH SMALL POPS...ESPECIALLY ACROSS NW PA. THE
REMAINDER OF THE NIGHT AND TUESDAY SHOULD BE DRY. MODELS STILL
PUSHING 850 MB TEMPS TO PLUS 20 OR WARMER ON TUESDAY. NEW GUIDANCE
IS A TAD COOLER WITH HIGHS BUT HAVE NOT MADE ANY SIGNIFICANT
CHANGES. MUCH OF THE AREA SHOULD REACH THE 90 DEGREE MARK. THE
WARM AND HUMID AIR MASS WILL REMAIN IN PLACE ON WEDNESDAY AS WELL.
THERE SHOULD BE MORE CLOUDS AND INCREASING CHANCES FOR PRECIP.
THIS WILL HOLD TEMPS BACK A LITTLE. IT APPEARS THAT THE BEST
CHANCES FOR CONVECTION DURING THE PERIOD WILL COME WEDNESDAY
EVENING AND NIGHT AS THE COLD FRONT FINALLY ARRIVES. HAVE GIVEN
MUCH OF THE AREA LIKELY POPS. THERE WILL BE A DISTINCT AIR MASS
CHANGE BEHIND THE FRONT. STRONG COLD AIR ADVECTION IS EXPECTED
BEHIND THE FRONT ON THURSDAY. THE MODELS TRY TO DRY THINGS OUT
QUICKLY BUT SUSPECT THAT THIS IS TOO FAST. WILL LIKELY SEE A FAIR
AMOUNT OF CLOUDINESS AND PERHAPS A FEW SHOWERS DOWN WIND OF THE
LAKE. AFTER TUESDAY HAVE USED A BLEND OF GUIDANCE TEMPS.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
TROUGH ALOFT FRIDAY WITH A VERY COOL AIR MASS. STILL GOOD CONSENSUS
THAT H8 TEMPS WILL BE BETWEEN +2C AND +5C. WILL KEEP THE HIGHS IN
THE 60S BOTH FRIDAY AND SATURDAY...WITH EVEN SOME UPPER 50S ACROSS
NW PA ON FRIDAY. FAIRLY CLOUDY TO START FRIDAY WITH ADDITIONAL LAKE
CLOUDS...BUT BY LATE AFTERNOON HIGH PRESSURE FROM THE CENTRAL LAKES
REALLY BEGINS TO BUILD IN. WILL ALSO KEEP SOME LOW PRECIP CHANCES
FOR LAKE EFFECT RAIN SHOWERS. SIGNIFICANT DRYING AND RIDGING BEGIN
TO WORK IN FOR SATURDAY...SO PRECIP SHOULD NOT BE A PROBLEM. NIGH
LOWS WILL BE COOL FOR SURE...BUT CLOUD COVER WILL BE THE DETERMINING
FACTOR ON HOW COOL. TEMPERATURE RECOVERY BEGINS SUNDAY AS THE HIGH
SHIFTS EAST AND WE GET RETURN FLOW. THE NEXT FRONTAL SYSTEM WILL BE
ACROSS THE NORTHERN AND CENTRAL LAKES COME SUNDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
THE WARM FRONT WILL BE SLOWLY MOVING NORTHEAST ACROSS THE
FORECAST AREA THIS AFTERNOON AND THE FIRST PART OF TONIGHT. CANNOT
RULE OUT A FEW NEW SHOWERS POPPING UP BUT MOST AREAS WILL LIKELY
SEE SCATTERED CUMULUS AND PATCHES OF MID AND HIGH CLOUDS AND
REMAIN VFR. THE SOUTH TO SOUTHWEST WIND WILL PICK UP...ESPECIALLY
TUESDAY MORNING. WE SHOULD BE CAPPED ON TUESDAY AS THE RIDGE ALOFT
BUILDS OVER THE AREA SO IT WILL LIKELY BE VFR/CLEAR.
OUTLOOK...NON VFR WITH POSSIBLE SHOWERS/THUNDERSTORMS WEDNESDAY
THROUGH THURSDAY. WILL LIKELY HAVE SOME NON VFR CEILINGS ACROSS
NE OH/NW PA THURSDAY AND FRIDAY.
&&
.MARINE...
SOUTHERLY FLOW TODAY AND A RELATIVELY NICE DAY ON THE LAKE. THERE
MAY BE A SHOWER OR THUNDERSTORM TODAY AS A WARM FRONT PUSHES
NORTHEAST ACROSS THE LAKE. FLOW COMES AROUND TO THE SOUTHWEST
TUESDAY AND PICKS UP ENOUGH THAT A SMALL CRAFT ADVISORY MAY BE
NEEDED ALONG THE EAST HALF/END. WINDS BEGIN TO DECREASE TUESDAY
NIGHT INTO WEDNESDAY AS A WEAKENING COLD FRONT BEGINS TO SINK SOUTH
ACROSS THE CENTRAL LAKES. WINDS SHIFT TO THE NORTHWEST BY THURSDAY
MORNING. SOME OF THE BETTER COLD AIR ADVECTION IS DELAYED UNTIL
FRIDAY. AT THAT POINT WINDS WILL PICK UP AND SMALL CRAFT CONDITIONS
WILL BE LIKELY. A MUCH COOLER AIR MASS WILL BRING LAKE EFFECT RAIN
SHOWERS TOO.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...DJB/KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...KOSARIK
MARINE...OUDEMAN
AREA FORECAST DISCUSSION...UPDATED
NWS CLEVELAND OH
916 AM EDT MON SEP 9 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES
WILL MOVE OFF THE NEW ENGLAND COAST TODAY. THIS WILL ALLOW A WARM
FRONT TO LIFT NORTHEAST ACROSS THE LOCAL AREA. AN AREA OF LOW
PRESSURE WILL PASS WELL TO THE NORTH ON WEDNESDAY AND DRAG A COLD
FRONT ACROSS THE REGION ON WEDNESDAY NIGHT. HIGH PRESSURE WILL
RETURN FOR THE END OF THE WORKWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
TWEAKED TEMPS UP A LITTLE IN THE EAST...OTHERWISE FORECAST LOOKS
GOOD.
ORIGINAL...QUITE A BIT OF SHOWER AND THUNDERSTORM ACTIVITY OVER SW LOWER
MICHIGAN. THIS ACTIVITY HAS FORMED ALONG A WARM FRONT THAT WILL
LIFT NE ACROSS THE LOCAL AREA TODAY. ALL OF THE NEW
GUIDANCE...INCLUDING THE HRRR AND CONVECTIVE SREF SHOW AT LEAST
SCATTERED PRECIP. HAVE BUMPED PRECIP CHANCES UP ALL AREAS TO
AROUND 40 PERCENT. MAY EVENTUALLY HAVE TO BUMP IT EVER FURTHER
DEPENDING ON WHAT THE ACTIVITY OVER MI DOES. DEWPOINTS ARE ALREADY ON
THE WAY UP AND EXPECTING MID 60S BY EARLY EVENING. THERE SHOULD
BE A LOT OF CLOUDINESS TODAY BUT TEMPS WILL STILL MAKE THE 80S
OVER ALL BUT THE EASTERN END OF THE AREA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
THE WARM FRONT WILL MOVE NORTH OF LAKE ERIE THIS EVENING AND THAT
SHOULD END THE THREAT FOR ADDITIONAL PRECIP. WILL START THE
TONIGHT PERIOD OUT WITH SMALL POPS...ESPECIALLY ACROSS NW PA. THE
REMAINDER OF THE NIGHT AND TUESDAY SHOULD BE DRY. MODELS STILL
PUSHING 850 MB TEMPS TO PLUS 20 OR WARMER ON TUESDAY. NEW GUIDANCE
IS A TAD COOLER WITH HIGHS BUT HAVE NOT MADE ANY SIGNIFICANT
CHANGES. MUCH OF THE AREA SHOULD REACH THE 90 DEGREE MARK. THE
WARM AND HUMID AIRMASS WILL REMAIN IN PLACE ON WEDNESDAY AS WELL.
THERE SHOULD BE MORE CLOUDS AND INCREASING CHANCES FOR PRECIP.
THIS WILL HOLD TEMPS BACK A LITTLE. IT APPEARS THAT THE BEST
CHANCES FOR CONVECTION DURING THE PERIOD WILL COME WEDNESDAY
EVENING AND NIGHT AS THE COLD FRONT FINALLY ARRIVES. HAVE GIVEN
MUCH OF THE AREA LIKELY POPS. THERE WILL BE A DISTINCT AIRMASS
CHANGE BEHIND THE FRONT. STRONG COLD AIR ADVECTION IS EXPECTED
BEHIND THE FRONT ON THURSDAY. THE MODELS TRY TO DRY THINGS OUT
QUICKLY BUT SUSPECT THAT THIS IS TOO FAST. WILL LIKELY SEE A FAIR
AMOUNT OF CLOUDINESS AND PERHAPS A FEW SHOWERS DOWN WIND OF THE
LAKE. AFTER TUESDAY HAVE USED A BLEND OF GUIDANCE TEMPS.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
TROUGH ALOFT FRIDAY WITH A VERY COOL AIRMASS. STILL GOOD CONSENSUS
THAT H8 TEMPS WILL BE BETWEEN +2C AND +5C. WILL KEEP THE HIGHS IN
THE 60S BOTH FRIDAY AND SATURDAY...WITH EVEN SOME UPPER 50S ACROSS
NW PA ON FRIDAY. FAIRLY CLOUDY TO START FRIDAY WITH ADDITIONAL LAKE
CLOUDS...BUT BY LATE AFTERNOON HIGH PRESSURE FROM THE CENTRAL LAKES
REALLY BEGINS TO BUILD IN. WILL ALSO KEEP SOME LOW PRECIP CHANCES
FOR LAKE EFFECT RAIN SHOWERS. SIGNIFICANT DRYING AND RIDGING BEGIN
TO WORK IN FOR SATURDAY...SO PRECIP SHOULD NOT BE A PROBLEM. NIGH
LOWS WILL BE COOL FOR SURE...BUT CLOUD COVER WILL BE THE DETERMINING
FACTOR ON HOW COOL. TEMPERATURE RECOVERY BEGINS SUNDAY AS THE HIGH
SHIFTS EAST AND WE GET RETURN FLOW. THE NEXT FRONTAL SYSTEM WILL BE
ACROSS THE NORTHERN AND CENTRAL LAKES COME SUNDAY.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE AND DRY AIRMASS JUST TO OUR NORTHEAST. TO OUR
SOUTHWEST THERE IS A MORE HUMID AIRMASS AND A DEVELOPING WARM
FRONT. SHOWERS AND A FEW TS HAVE DEVELOPED AND PROPAGATED ACROSS
SOUTHERN LOWER MI AHEAD OF THE WARM FRONT...HEADING TOWARD TOL.
HAVE INCLUDED A VCTS FOR TOL...WITH ONLY LIMITED CLOUD-GROUND
LIGHTNING POSSIBLE AND A WEAKENING TREND ON RADAR MOSAIC. MVFR
CONDITIONS IN THE -RA LIKELY THOUGH. NOT EXPECTING THIS AREA OF
RAIN TO MAKE IT TOO MUCH FURTHER SE...BUT INSTEAD NEW SCATTERED
DEVELOPMENT POSSIBLE ALONG THAT WARM FRONT THIS AFTERNOON. WITH
CHANCES STILL AROUND 30 PERCENT OR SO...HAVE GONE WITH A VCSH
MENTION. THUNDER IS POSSIBLE...BUT HARD TO PINPOINT JUST YET.
WINDS WILL COME AROUND FROM THE ESE TO THE SOUTH WITH THE PASSAGE
OF THE FRONT. RIDGE REALLY BUILDS IN MONDAY EVENING AND PRECIP
CHANCES ARE EXPECTED TO BE OVER. VARIABLY CLOUDY WITH MID/HIGH
CLOUDS OVERNIGHT. SOUTH WIND STAYS UP AT 10 OR 12 KNOTS.
OUTLOOK...NON VFR WITH POSSIBLE SHOWERS/THUNDERSTORMS WEDNESDAY
THROUGH THURSDAY. MAY HAVE SOME NON VFR CEILINGS ACROSS THE
SNOWBELT THURSDAY AND FRIDAY.
&&
.MARINE...
SOUTHERLY FLOW TODAY AND A RELATIVELY NICE DAY ON THE LAKE. THERE
MAY BE A SHOWER OR THUNDERSTORM TODAY AS A WARM FRONT PUSHES
NORTHEAST ACROSS THE LAKE. FLOW COMES AROUND TO THE SOUTHWEST
TUESDAY AND PICKS UP ENOUGH THAT A SMALL CRAFT ADVISORY MAY BE
NEEDED ALONG THE EAST HALF/END. WINDS BEGIN TO DECREASE TUESDAY
NIGHT INTO WEDNESDAY AS A WEAKENING COLD FRONT BEGINS TO SINK SOUTH
ACROSS THE CENTRAL LAKES. WINDS SHIFT TO THE NORTHWEST BY THURSDAY
MORNING. SOME OF THE BETTER COLD AIR ADVECTION IS DELAYED UNTIL
FRIDAY. AT THAT POINT WINDS WILL PICK UP AND SMALL CRAFT CONDITIONS
WILL BE LIKELY. A MUCH COOLER AIRMASS WILL BRING LAKE EFFECT RAIN
SHOWERS TOO.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...DJB/KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
729 AM EDT MON SEP 9 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES
WILL MOVE OFF THE NEW ENGLAND COAST TODAY. THIS WILL ALLOW A WARM
FRONT TO LIFT NORTHEAST ACROSS THE LOCAL AREA. AN AREA OF LOW
PRESSURE WILL PASS WELL TO THE NORTH ON WEDNESDAY AND DRAG A COLD
FRONT ACROSS THE REGION ON WEDNESDAY NIGHT. HIGH PRESSURE WILL
RETURN FOR THE END OF THE WORKWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE FINE TUNED PRECIP CHANCES THE NEXT FEW HOURS BASED ON RADAR
TRENDS. HAVE GONE WITH LIKELY POPS FOR A COUPLE OF COUNTIES IN NW
OH. THE PRECIP APPROACHING FROM THE WNW CONTINUES TO WEAKEN AND
VERY LITTLE LIGHTNING LEFT. THIS FIRST WAVE OF PRECIP SHOULD
DISSIPATE BEFORE GETTING TOO FAR INTO THE AREA. NEW DEVELOPMENT IS
LIKELY LATER THIS MORNING AS THE WARM FRONT APPROACHES FROM THE
SW.
ORIGINAL...QUITE A BIT OF SHOWER AND THUNDERSTORM ACTIVITY OVER SW LOWER
MICHIGAN. THIS ACTIVITY HAS FORMED ALONG A WARM FRONT THAT WILL
LIFT NE ACROSS THE LOCAL AREA TODAY. ALL OF THE NEW
GUIDANCE...INCLUDING THE HRRR AND CONVECTIVE SREF SHOW AT LEAST
SCATTERED PRECIP. HAVE BUMPED PRECIP CHANCES UP ALL AREAS TO
AROUND 40 PERCENT. MAY EVENTUALLY HAVE TO BUMP IT EVER FURTHER
DEPENDING ON WHAT THE ACTIVITY OVER MI DOES. DEWPOINTS ARE ALREADY ON
THE WAY UP AND EXPECTING MID 60S BY EARLY EVENING. THERE SHOULD
BE A LOT OF CLOUDINESS TODAY BUT TEMPS WILL STILL MAKE THE 80S
OVER ALL BUT THE EASTERN END OF THE AREA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
THE WARM FRONT WILL MOVE NORTH OF LAKE ERIE THIS EVENING AND THAT
SHOULD END THE THREAT FOR ADDITIONAL PRECIP. WILL START THE
TONIGHT PERIOD OUT WITH SMALL POPS...ESPECIALLY ACROSS NW PA. THE
REMAINDER OF THE NIGHT AND TUESDAY SHOULD BE DRY. MODELS STILL
PUSHING 850 MB TEMPS TO PLUS 20 OR WARMER ON TUESDAY. NEW GUIDANCE
IS A TAD COOLER WITH HIGHS BUT HAVE NOT MADE ANY SIGNIFICANT
CHANGES. MUCH OF THE AREA SHOULD REACH THE 90 DEGREE MARK. THE
WARM AND HUMID AIRMASS WILL REMAIN IN PLACE ON WEDNESDAY AS WELL.
THERE SHOULD BE MORE CLOUDS AND INCREASING CHANCES FOR PRECIP.
THIS WILL HOLD TEMPS BACK A LITTLE. IT APPEARS THAT THE BEST
CHANCES FOR CONVECTION DURING THE PERIOD WILL COME WEDNESDAY
EVENING AND NIGHT AS THE COLD FRONT FINALLY ARRIVES. HAVE GIVEN
MUCH OF THE AREA LIKELY POPS. THERE WILL BE A DISTINCT AIRMASS
CHANGE BEHIND THE FRONT. STRONG COLD AIR ADVECTION IS EXPECTED
BEHIND THE FRONT ON THURSDAY. THE MODELS TRY TO DRY THINGS OUT
QUICKLY BUT SUSPECT THAT THIS IS TOO FAST. WILL LIKELY SEE A FAIR
AMOUNT OF CLOUDINESS AND PERHAPS A FEW SHOWERS DOWN WIND OF THE
LAKE. AFTER TUESDAY HAVE USED A BLEND OF GUIDANCE TEMPS.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
TROUGH ALOFT FRIDAY WITH A VERY COOL AIRMASS. STILL GOOD CONSENSUS
THAT H8 TEMPS WILL BE BETWEEN +2C AND +5C. WILL KEEP THE HIGHS IN
THE 60S BOTH FRIDAY AND SATURDAY...WITH EVEN SOME UPPER 50S ACROSS
NW PA ON FRIDAY. FAIRLY CLOUDY TO START FRIDAY WITH ADDITIONAL LAKE
CLOUDS...BUT BY LATE AFTERNOON HIGH PRESSURE FROM THE CENTRAL LAKES
REALLY BEGINS TO BUILD IN. WILL ALSO KEEP SOME LOW PRECIP CHANCES
FOR LAKE EFFECT RAIN SHOWERS. SIGNIFICANT DRYING AND RIDGING BEGIN
TO WORK IN FOR SATURDAY...SO PRECIP SHOULD NOT BE A PROBLEM. NIGH
LOWS WILL BE COOL FOR SURE...BUT CLOUD COVER WILL BE THE DETERMINING
FACTOR ON HOW COOL. TEMPERATURE RECOVERY BEGINS SUNDAY AS THE HIGH
SHIFTS EAST AND WE GET RETURN FLOW. THE NEXT FRONTAL SYSTEM WILL BE
ACROSS THE NORTHERN AND CENTRAL LAKES COME SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE AND DRY AIRMASS JUST TO OUR NORTHEAST. TO OUR
SOUTHWEST THERE IS A MORE HUMID AIRMASS AND A DEVELOPING WARM
FRONT. SHOWERS AND A FEW TS HAVE DEVELOPED AND PROPAGATED ACROSS
SOUTHERN LOWER MI AHEAD OF THE WARM FRONT...HEADING TOWARD TOL.
HAVE INCLUDED A VCTS FOR TOL...WITH ONLY LIMITED CLOUD-GROUND
LIGHTNING POSSIBLE AND A WEAKENING TREND ON RADAR MOSAIC. MVFR
CONDITIONS IN THE -RA LIKELY THOUGH. NOT EXPECTING THIS AREA OF
RAIN TO MAKE IT TOO MUCH FURTHER SE...BUT INSTEAD NEW SCATTERED
DEVELOPMENT POSSIBLE ALONG THAT WARM FRONT THIS AFTERNOON. WITH
CHANCES STILL AROUND 30 PERCENT OR SO...HAVE GONE WITH A VCSH
MENTION. THUNDER IS POSSIBLE...BUT HARD TO PINPOINT JUST YET.
WINDS WILL COME AROUND FROM THE ESE TO THE SOUTH WITH THE PASSAGE
OF THE FRONT. RIDGE REALLY BUILDS IN MONDAY EVENING AND PRECIP
CHANCES ARE EXPECTED TO BE OVER. VARIABLY CLOUDY WITH MID/HIGH
CLOUDS OVERNIGHT. SOUTH WIND STAYS UP AT 10 OR 12 KNOTS.
OUTLOOK...NON VFR WITH POSSIBLE SHOWERS/THUNDERSTORMS WEDNESDAY
THROUGH THURSDAY. MAY HAVE SOME NON VFR CEILINGS ACROSS THE
SNOWBELT THURSDAY AND FRIDAY.
&&
.MARINE...
SOUTHERLY FLOW TODAY AND A RELATIVELY NICE DAY ON THE LAKE. THERE
MAY BE A SHOWER OR THUNDERSTORM TODAY AS A WARM FRONT PUSHES
NORTHEAST ACROSS THE LAKE. FLOW COMES AROUND TO THE SOUTHWEST
TUESDAY AND PICKS UP ENOUGH THAT A SMALL CRAFT ADVISORY MAY BE
NEEDED ALONG THE EAST HALF/END. WINDS BEGIN TO DECREASE TUESDAY
NIGHT INTO WEDNESDAY AS A WEAKENING COLD FRONT BEGINS TO SINK SOUTH
ACROSS THE CENTRAL LAKES. WINDS SHIFT TO THE NORTHWEST BY THURSDAY
MORNING. SOME OF THE BETTER COLD AIR ADVECTION IS DELAYED UNTIL
FRIDAY. AT THAT POINT WINDS WILL PICK UP AND SMALL CRAFT CONDITIONS
WILL BE LIKELY. A MUCH COOLER AIRMASS WILL BRING LAKE EFFECT RAIN
SHOWERS TOO.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
622 AM EDT MON SEP 9 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES
WILL MOVE OFF THE NEW ENGLAND COAST TODAY. THIS WILL ALLOW A WARM
FRONT TO LIFT NORTHEAST ACROSS THE LOCAL AREA. AN AREA OF LOW
PRESSURE WILL PASS WELL TO THE NORTH ON WEDNESDAY AND DRAG A COLD
FRONT ACROSS THE REGION ON WEDNESDAY NIGHT. HIGH PRESSURE WILL
RETURN FOR THE END OF THE WORKWEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
HAVE FINE TUNED PRECIP CHANCES THE NEXT FEW HOURS BASED ON RADAR
TRENDS. HAVE GONE WITH LIKELY POPS FOR A COUPLE OF COUNTIES IN NW
OH. THE PRECIP APPROACHING FROM THE WNW CONTINUES TO WEAKEN AND
VERY LITTLE LIGHTNING LEFT. THIS FIRST WAVE OF PRECIP SHOULD
DISSIPATE BEFORE GETTING TOO FAR INTO THE AREA. NEW DEVELOPMENT IS
LIKELY LATER THIS MORNING AS THE WARM FRONT APPROACHES FROM THE
SW.
ORIGINAL...QUITE A BIT OF SHOWER AND THUNDERSTORM ACTIVITY OVER SW LOWER
MICHIGAN. THIS ACTIVITY HAS FORMED ALONG A WARM FRONT THAT WILL
LIFT NE ACROSS THE LOCAL AREA TODAY. ALL OF THE NEW
GUIDANCE...INCLUDING THE HRRR AND CONVECTIVE SREF SHOW AT LEAST
SCATTERED PRECIP. HAVE BUMPED PRECIP CHANCES UP ALL AREAS TO
AROUND 40 PERCENT. MAY EVENTUALLY HAVE TO BUMP IT EVER FURTHER
DEPENDING ON WHAT THE ACTIVITY OVER MI DOES. DEWPOINTS ARE ALREADY ON
THE WAY UP AND EXPECTING MID 60S BY EARLY EVENING. THERE SHOULD
BE A LOT OF CLOUDINESS TODAY BUT TEMPS WILL STILL MAKE THE 80S
OVER ALL BUT THE EASTERN END OF THE AREA.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
THE WARM FRONT WILL MOVE NORTH OF LAKE ERIE THIS EVENING AND THAT
SHOULD END THE THREAT FOR ADDITIONAL PRECIP. WILL START THE
TONIGHT PERIOD OUT WITH SMALL POPS...ESPECIALLY ACROSS NW PA. THE
REMAINDER OF THE NIGHT AND TUESDAY SHOULD BE DRY. MODELS STILL
PUSHING 850 MB TEMPS TO PLUS 20 OR WARMER ON TUESDAY. NEW GUIDANCE
IS A TAD COOLER WITH HIGHS BUT HAVE NOT MADE ANY SIGNIFICANT
CHANGES. MUCH OF THE AREA SHOULD REACH THE 90 DEGREE MARK. THE
WARM AND HUMID AIRMASS WILL REMAIN IN PLACE ON WEDNESDAY AS WELL.
THERE SHOULD BE MORE CLOUDS AND INCREASING CHANCES FOR PRECIP.
THIS WILL HOLD TEMPS BACK A LITTLE. IT APPEARS THAT THE BEST
CHANCES FOR CONVECTION DURING THE PERIOD WILL COME WEDNESDAY
EVENING AND NIGHT AS THE COLD FRONT FINALLY ARRIVES. HAVE GIVEN
MUCH OF THE AREA LIKELY POPS. THERE WILL BE A DISTINCT AIRMASS
CHANGE BEHIND THE FRONT. STRONG COLD AIR ADVECTION IS EXPECTED
BEHIND THE FRONT ON THURSDAY. THE MODELS TRY TO DRY THINGS OUT
QUICKLY BUT SUSPECT THAT THIS IS TOO FAST. WILL LIKELY SEE A FAIR
AMOUNT OF CLOUDINESS AND PERHAPS A FEW SHOWERS DOWN WIND OF THE
LAKE. AFTER TUESDAY HAVE USED A BLEND OF GUIDANCE TEMPS.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
TROUGH ALOFT FRIDAY WITH A VERY COOL AIRMASS. STILL GOOD CONSENSUS
THAT H8 TEMPS WILL BE BETWEEN +2C AND +5C. WILL KEEP THE HIGHS IN
THE 60S BOTH FRIDAY AND SATURDAY...WITH EVEN SOME UPPER 50S ACROSS
NW PA ON FRIDAY. FAIRLY CLOUDY TO START FRIDAY WITH ADDITIONAL LAKE
CLOUDS...BUT BY LATE AFTERNOON HIGH PRESSURE FROM THE CENTRAL LAKES
REALLY BEGINS TO BUILD IN. WILL ALSO KEEP SOME LOW PRECIP CHANCES
FOR LAKE EFFECT RAIN SHOWERS. SIGNIFICANT DRYING AND RIDGING BEGIN
TO WORK IN FOR SATURDAY...SO PRECIP SHOULD NOT BE A PROBLEM. NIGH
LOWS WILL BE COOL FOR SURE...BUT CLOUD COVER WILL BE THE DETERMINING
FACTOR ON HOW COOL. TEMPERATURE RECOVERY BEGINS SUNDAY AS THE HIGH
SHIFTS EAST AND WE GET RETURN FLOW. THE NEXT FRONTAL SYSTEM WILL BE
ACROSS THE NORTHERN AND CENTRAL LAKES COME SUNDAY.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE AND DRY AIRMASS JUST TO OUR NORTHEAST. TO OUR
SOUTHWEST THERE IS A MORE HUMID AIRMASS AND A DEVELOPING WARM
FRONT. THE DRY AIR IN COMBINATION WITH ALL OF THE HIGH CLOUD
PRESENTLY OVER THE AREA SHOULD LIMIT ANY EARLY MORNING BR ISSUES.
ALREADY STARTING TO SEE SOME MID CLOUD DEVELOPMENT OFF THE WARM
FRONT. OBSERVATIONS ARE COMING IN BETWEEN 5K AND 7K FEET. WITH
THAT HAVE REMOVED THE MENTIONS OF 3K FEET LOCALLY AND RAISED THAT
TO VFR. WARM FRONT WILL PUSH NORTHEAST TODAY AND BRING EASTERLY
WINDS AROUND TO THE SOUTH. MOST OF OUR FORECAST MODELS WANT TO
DEVELOP A FEW SHOWERS/POSSIBLY A TS/ ACROSS THE AREA THIS
AFTERNOON. HAVE CONTINUED WITH THE SHRA MENTION IN PROB GROUPS.
RIDGE REALLY BUILDS IN MONDAY EVENING AND PRECIP CHANCES ARE
EXPECTED TO BE OVER.
OUTLOOK...NON VFR WITH POSSIBLE SHOWERS/THUNDERSTORMS WEDNESDAY
THROUGH THURSDAY. MAY HAVE SOME NON VFR CEILINGS ACROSS THE
SNOWBELT THURSDAY AND FRIDAY.
&&
.MARINE...
SOUTHERLY FLOW TODAY AND A RELATIVELY NICE DAY ON THE LAKE. THERE
MAY BE A SHOWER OR THUNDERSTORM TODAY AS A WARM FRONT PUSHES
NORTHEAST ACROSS THE LAKE. FLOW COMES AROUND TO THE SOUTHWEST
TUESDAY AND PICKS UP ENOUGH THAT A SMALL CRAFT ADVISORY MAY BE
NEEDED ALONG THE EAST HALF/END. WINDS BEGIN TO DECREASE TUESDAY
NIGHT INTO WEDNESDAY AS A WEAKENING COLD FRONT BEGINS TO SINK SOUTH
ACROSS THE CENTRAL LAKES. WINDS SHIFT TO THE NORTHWEST BY THURSDAY
MORNING. SOME OF THE BETTER COLD AIR ADVECTION IS DELAYED UNTIL
FRIDAY. AT THAT POINT WINDS WILL PICK UP AND SMALL CRAFT CONDITIONS
WILL BE LIKELY. A MUCH COOLER AIRMASS WILL BRING LAKE EFFECT RAIN
SHOWERS TOO.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
348 AM EDT MON SEP 9 2013
.SYNOPSIS...
AN AREA OF HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES
WILL MOVE OFF THE NEW ENGLAND COAST TODAY. THIS WILL ALLOW A WARM
FRONT TO LIFT NORTHEAST ACROSS THE LOCAL AREA. AN AREA OF LOW
PRESSURE WILL PASS WELL TO THE NORTH ON WEDNESDAY AND DRAG A COLD
FRONT ACROSS THE REGION ON WEDNESDAY NIGHT. HIGH PRESSURE WILL
RETURN FOR THE END OF THE WORKWEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
QUITE A BIT OF SHOWER AND THUNDERSTORM ACTIVITY OVER SW LOWER
MICHIGAN. THIS ACTIVITY HAS FORMED ALONG A WARM FRONT THAT WILL
LIFT NE ACROSS THE LOCAL AREA TODAY. ALL OF THE NEW
GUIDANCE...INCLUDING THE HRRR AND CONVECTIVE SREF SHOW AT LEAST
SCATTERED PRECIP. HAVE BUMPED PRECIP CHANCES UP ALL AREAS TO
AROUND 40 PERCENT. MAY EVENTUALLY HAVE TO BUMP IT EVER FURTHER
DEPENDING ON WHAT THE ACTIVITY OVER MI DOES. DEWPOINTS ARE ALREADY ON
THE WAY UP AND EXPECTING MID 60S BY EARLY EVENING. THERE SHOULD
BE A LOT OF CLOUDINESS TODAY BUT TEMPS WILL STILL MAKE THE 80S
OVER ALL BUT THE EASTERN END OF THE AREA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
THE WARM FRONT WILL MOVE NORTH OF LAKE ERIE THIS EVENING AND THAT
SHOULD END THE THREAT FOR ADDITIONAL PRECIP. WILL START THE
TONIGHT PERIOD OUT WITH SMALL POPS...ESPECIALLY ACROSS NW PA. THE
REMAINDER OF THE NIGHT AND TUESDAY SHOULD BE DRY. MODELS STILL
PUSHING 850 MB TEMPS TO PLUS 20 OR WARMER ON TUESDAY. NEW GUIDANCE
IS A TAD COOLER WITH HIGHS BUT HAVE NOT MADE ANY SIGNIFICANT
CHANGES. MUCH OF THE AREA SHOULD REACH THE 90 DEGREE MARK. THE
WARM AND HUMID AIRMASS WILL REMAIN IN PLACE ON WEDNESDAY AS WELL.
THERE SHOULD BE MORE CLOUDS AND INCREASING CHANCES FOR PRECIP.
THIS WILL HOLD TEMPS BACK A LITTLE. IT APPEARS THAT THE BEST
CHANCES FOR CONVECTION DURING THE PERIOD WILL COME WEDNESDAY
EVENING AND NIGHT AS THE COLD FRONT FINALLY ARRIVES. HAVE GIVEN
MUCH OF THE AREA LIKELY POPS. THERE WILL BE A DISTINCT AIRMASS
CHANGE BEHIND THE FRONT. STRONG COLD AIR ADVECTION IS EXPECTED
BEHIND THE FRONT ON THURSDAY. THE MODELS TRY TO DRY THINGS OUT
QUICKLY BUT SUSPECT THAT THIS IS TOO FAST. WILL LIKELY SEE A FAIR
AMOUNT OF CLOUDINESS AND PERHAPS A FEW SHOWERS DOWN WIND OF THE
LAKE. AFTER TUESDAY HAVE USED A BLEND OF GUIDANCE TEMPS.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
TROUGH ALOFT FRIDAY WITH A VERY COOL AIRMASS. STILL GOOD CONSENSUS
THAT H8 TEMPS WILL BE BETWEEN +2C AND +5C. WILL KEEP THE HIGHS IN
THE 60S BOTH FRIDAY AND SATURDAY...WITH EVEN SOME UPPER 50S ACROSS
NW PA ON FRIDAY. FAIRLY CLOUDY TO START FRIDAY WITH ADDITIONAL LAKE
CLOUDS...BUT BY LATE AFTERNOON HIGH PRESSURE FROM THE CENTRAL LAKES
REALLY BEGINS TO BUILD IN. WILL ALSO KEEP SOME LOW PRECIP CHANCES
FOR LAKE EFFECT RAIN SHOWERS. SIGNIFICANT DRYING AND RIDGING BEGIN
TO WORK IN FOR SATURDAY...SO PRECIP SHOULD NOT BE A PROBLEM. NIGH
LOWS WILL BE COOL FOR SURE...BUT CLOUD COVER WILL BE THE DETERMINING
FACTOR ON HOW COOL. TEMPERATURE RECOVERY BEGINS SUNDAY AS THE HIGH
SHIFTS EAST AND WE GET RETURN FLOW. THE NEXT FRONTAL SYSTEM WILL BE
ACROSS THE NORTHERN AND CENTRAL LAKES COME SUNDAY.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE AND DRY AIRMASS JUST TO OUR NORTHEAST. TO OUR
SOUTHWEST THERE IS A MORE HUMID AIRMASS AND A DEVELOPING WARM
FRONT. THE DRY AIR IN COMBINATION WITH ALL OF THE HIGH CLOUD
PRESENTLY OVER THE AREA SHOULD LIMIT ANY EARLY MORNING BR ISSUES.
ALREADY STARTING TO SEE SOME MID CLOUD DEVELOPMENT OFF THE WARM
FRONT. OBSERVATIONS ARE COMING IN BETWEEN 5K AND 7K FEET. WITH
THAT HAVE REMOVED THE MENTIONS OF 3K FEET LOCALLY AND RAISED THAT
TO VFR. WARM FRONT WILL PUSH NORTHEAST TODAY AND BRING EASTERLY
WINDS AROUND TO THE SOUTH. MOST OF OUR FORECAST MODELS WANT TO
DEVELOP A FEW SHOWERS/POSSIBLY A TS/ ACROSS THE AREA THIS
AFTERNOON. HAVE CONTINUED WITH THE SHRA MENTION IN PROB GROUPS.
RIDGE REALLY BUILDS IN MONDAY EVENING AND PRECIP CHANCES ARE
EXPECTED TO BE OVER.
OUTLOOK...NON VFR WITH POSSIBLE SHOWERS/THUNDERSTORMS WEDNESDAY
THROUGH THURSDAY. MAY HAVE SOME NON VFR CEILINGS ACROSS THE
SNOWBELT THURSDAY AND FRIDAY.
&&
.MARINE...
SOUTHERLY FLOW TODAY AND A RELATIVELY NICE DAY ON THE LAKE. THERE
MAY BE A SHOWER OR THUNDERSTORM TODAY AS A WARM FRONT PUSHES
NORTHEAST ACROSS THE LAKE. FLOW COMES AROUND TO THE SOUTHWEST
TUESDAY AND PICKS UP ENOUGH THAT A SMALL CRAFT ADVISORY MAY BE
NEEDED ALONG THE EAST HALF/END. WINDS BEGIN TO DECREASE TUESDAY
NIGHT INTO WEDNESDAY AS A WEAKENING COLD FRONT BEGINS TO SINK SOUTH
ACROSS THE CENTRAL LAKES. WINDS SHIFT TO THE NORTHWEST BY THURSDAY
MORNING. SOME OF THE BETTER COLD AIR ADVECTION IS DELAYED UNTIL
FRIDAY. AT THAT POINT WINDS WILL PICK UP AND SMALL CRAFT CONDITIONS
WILL BE LIKELY. A MUCH COOLER AIRMASS WILL BRING LAKE EFFECT RAIN
SHOWERS TOO.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
559 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WARM FRONT DRAPED ACROSS WESTERN PENNSYLVANIA THIS EVENING WILL
PUSH THROUGH THE ENTIRE REGION EARLY TUESDAY MORNING. UNSEASONABLY
HOT AND HUMID CONDITIONS ARE EXPECTED THROUGH MIDWEEK WITH
SCATTERED SHOWERS AND THUNDERSTORMS. A SIGNIFICANT COOLING TREND
IS EXPECTED BEHIND A COLD FRONT WITH BELOW NORMAL TEMPERATURES
FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SFC ANALYSIS PLACES WARM FRONT ACROSS WESTERN PA EARLY THIS
EVENING. HEATING OF WARM/HUMID AIR MASS WEST OF FRONT HAS RESULTED
IN CAPES NR 2000 J/KG /21Z SPC MESOANALYSIS/ AND SCT TSRA IN THE
VICINITY OF PITTSBURGH. JUST TO THE NE...EDGE OF THE WARM
ADVECTION IS PRODUCING ABUNDANT CLOUD COVER AND A FEW SHRA RUNNING
FROM NR ERIE INTO CENTRAL PA.
ANY TSRA WILL VERY LIKELY DIE...AS THEY DRIFT TOWARD MORE STABLE
AIR MASS ACROSS THE LAUREL HIGHLANDS THIS EVENING. HOWEVER...HAVE
RAISED POPS CONSIDERABLY ACROSS THE NW MTNS BASED ON LATEST RADAR
TRENDS. THE ENTIRE REGION STANDS THE CHC OF SEEING A SHOWER
OVERNIGHT AS WARM FRONT PUSHES INTO THE AREA. HOWEVER...WITH
EXCEPTION OF EARLY SHOWERS OVR THE NW MTNS...WILL KEEP POPS ON THE
LOW SIDE BASED ON OPER AND ENSEMBLE QPF.
ANOTHER ISSUE CONCERNS THE POTENTIAL OF FOG LATE TONIGHT. AREA
MOST LIKELY TO SEE SIG VSBY REDUCTIONS WILL BE JUST NORTH OF THE
WARM FRONT ACROSS NE PA. LATEST SREF AND RAP SUPPORT THIS SCENARIO
WITH THE NE COUNTIES SEEING THE HIGHEST PROBS OF LOW VSBY AND
HIGHEST SFC RH/S RESPECTIVELY.
CLOUD COVER AND INCREASING HUMIDITY WILL LEAD TO A MUCH MILDER
NIGHT WITH LOWS RANGING FROM THE U50S ACROSS THE NE COUNTIES...TO
BTWN 60-65F ELSEWHERE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
TUESDAY LOOKS LIKE AN ALMOST TYPICAL MID SUMMER DAY WITH HIGHS
WELL UP INTO THE 80S IN MOST PLACES...ALONG WITH HUMIDITY
BORDERING ON OPPRESSIVE. AN ISOLATED SHOWER OR STORM CANNOT BE
RULED OUT BUT WITH MODEL FCST TEMPS IN THE MID LEVELS TOPPING
10C...THE CAP WILL BE PRETTY HARD TO BREAK. I PLAN ON DOWNPLAYING
THE ALREADY LOW POPS WE HAVE IN THE FCST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
PARTLY TO MOSTLY CLOUDY SKIES TUESDAY NIGHT WITHIN THE EXTENSIVE
WARM SECTOR...WILL COMBINE WITH A SOUTHERLY LIGHT WIND AND SFC
DEWPOINTS IN THE MID TO UPPER 60S...LEADING TO A MUGGY NIGHT WITH
JUST A SCHC FOR TSRA PERSISTING ACROSS NRN PENN.
LIKELY THE HOTTEST DAY UNTIL LATER NEXT SPRING OR SUMMER WILL OCCUR
WEDNESDAY...WITH HIGH TEMPS REACHING INTO THE MID 80S /MTNS/ AND
LOWER 90S ACROSS THE LOWER SUSQ VALLEY.
A PRE-FRONTAL/LEE TROF WILL LIKELY DEVELOP ACROSS THE SUSQ VALLEY
WEDNESDAY...HELPING TO FOCUS THE BEST CHC FOR AT LEAST SCATTERED
AFTERNOON TSRA THERE. ACROSS THE NW...THE FIRST OF TWO SFC CFRONTS
WILL APPROACH LATER IN THE DAY/EVENING...SPARKING A BKN BAND OF
SHOWERS AND SCATTERED TSRA.
THE PAIR OF COLD FRONTS WILL MOVES SE ACROSS THE STATE WED NIGHT AND
THURSDAY...WITH ANOTHER ROUND OR TO OF SHOWERS/TSRA. FOR LATE IN THE
WEEK AND OVER THE UPCOMING WEEKEND...A SPRAWLING/COOL CANADIAN HIGH
AND ANOMALOUSLY DEEP UPPER TROUGH WILL MOVE SOUTHEAST FROM THE
GLAKES...BRINGING A RETURN TO MUCH LOWER DEWPOINTS AND BELOW NORMAL
TEMPS.
THE ZERO C 850 MB ISOTHERM /IN THE LATEST...03Z SREF/ WILL MOVE OVER
THE NRN GREAT LAKES REGION THURSDAY...BEFORE DIVING SOUTHEAST TO
MAKE A RARE EARLY SEASON APPEARANCE NEAR THE PENN/NEW YORK BORDER
AND SOUTHERN NEW ENGLAND COAST FRIDAY INTO EARLY SATURDAY. THESE -2
TO -3 SIGMA TEMPS AT 850 MB WILL UNDOUBTEDLY LEAD TO WIDESPREAD COLD
AIR STRATO CU WITH LAKE EFFECT AND OROGRAPHICALLY ENHANCED SHOWERS.
WE MAY BE UNDERPLAYING THE AMOUNT OF CLOUDS AND POPS FOR FRIDAY AND
SATURDAY HERE IN CENTRAL AND NRN PENN WITHIN THE COLD...GUSTY AND
WELL-ALIGNED DEEP NWRLY FLOW.
SO...IN SUMMARY...THE MAIN STORIES FOR THIS PERIOD WILL BE THE HEAT
TO START...SCATTERED STRONG TO SEVERE STORMS POSSIBLE LATER TUESDAY
AND WEDNESDAY...MAINLY NORTH OF THE REGION/...AND THE UNSEASONABLY
CHILLY AIRMASS TO CLOSE IT OUT.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
VIZ LOOP SHOWS LOW CLOUDS BUILDING IN THE WEAK UPSLOPE FLOW OVER
SOUTH CENTRAL PA. THE AOO CIG HAS ACTUALLY BEEN LOWERING DESPITE
WHAT LOOKS LIKE SOME MIXING STARTING TO DEVELOP IN THE LOW CLOUD
SHIELD. WOULD NOT BE SURPRISED TO EVEN SEE THE CEILING AT UNV GO
BRIEFLY MVFR BEFORE THE CLOUDS MIC AND BASES LIFT UP THIS
AFTERNOON.
THE LARGER PICTURE SHOWS AN INCREASINGLY MOIST SOUTHERLY FLOW
BEGINNING TO DEVELOP WHICH WILL BRING A CHANCE OF A SHOWER OR
THUNDERSTORM LATER TODAY INTO TONIGHT...MAINLY OVER WESTERN
AREAS.
MVFR/IFR CIGS ARE LIKELY ACROSS THE SERN TERMINALS LATE
TONIGHT. LOW CIGS WILL IMPROVE EARLY TUES GIVING WAY TO VFR BY
TUES AFTERNOON.
OUTLOOK...
TUE...AM LOW CLOUDS SOUTH/EAST.
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST.
SAT...NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD/LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...GARTNER/MARTIN
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
227 AM EDT MON SEP 9 2013
.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE POCONOS/CATSKILLS THIS MORNING
WILL SLIDE OFF THE NORTHERN MID-ATLANTIC COAST LATER TODAY. A
DEVELOPING SOUTHERLY RETURN FLOW AROUND THE WESTERN PERIPHERY OF
THE DEPARTING HIGH PRESSURE SYSTEM WILL LIFT A WARM FRONT NORTHWARD
ACROSS THE AREA LATE TONIGHT INTO EARLY TUESDAY. HOT AND HUMID
SUMMER-LIKE CONDITIONS ARE EXPECTED THROUGH MIDWEEK BEFORE A COLD
FRONT MOVES THROUGH ON THURSDAY. FAIR WEATHER AND SEASONABLY COOL
TEMPERATURES SHOULD RETURN BY FRIDAY AND LAST INTO THE WEEKEND..AS
ANOTHER CANADIAN AIR MASS ACCOMPANIES HIGH PRESSURE BACK INTO THE
REGION.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
1022 MB SFC HIGH WAS CENTERED ACROSS SCENT NEW YORK AT 06Z. THE
MODIFIED CANADIAN AIR MASS ACCOMPANYING THIS HIGH PRES SYSTEM IS NOT
QUITE AS COOL AND CHILLY AS THE ONE OF A FEW DAYS PAST. HOWEVER...
STILL CANT RULE OUT SOME PATCHY FROST ACROSS THE COLDER POCKETS OF
THE NRN MTNS WHERE MINS SHOULD DIP INTO THE UPPER 30S. MID 40S TO
LOW 50S WILL BE COMMON ELSEWHERE. ALSO LOOK FOR FOG TO FORM IN THE
NRN RIVER/STREAM VALLEYS TOWARDS DAWN...AS WIND BECOMES NEARLY CALM.
EARLY MORNING IR LOOP SHOWS THIN CIRRUS SPILLING SE FROM THE LOWER
GLAKES REGION AND SPREAD ACROSS MUCH OF CENTRAL PENN.
THE SFC COLD FRONTAL BOUNDARY HAS PUSHED WELL TO THE SOUTH OF THE
MASON/DIXON LINE. HOWEVER...THE SHALLOW BOUNDARY AND MOISTURE IN THE
925-850 MB LAYER IS BEGINNING TO NOSE BACK NORTH INTO SCENT PENN AND
THE LAUREL HIGHLANDS...ACCOMPANIED BY A BKN-OVC STRATOCU DECK OF
3.5-5 KFT AGL. MORE ON THIS ASPECT OF TODAY`S WEATHER BELOW.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THE SFC HIGH IS EXPECTED TO QUICKLY SLIDE OFF THE EAST COAST DURING
THE DAY TODAY SETTING UP A RETURN FLOW OF AIR OUT OF THE SOUTH.
00Z NAM...AND 05Z RUC INDICATES THAT WE/LL SEE THE HIGHER MOISTURE
IN THE 925-850 MB LAYER ADVECT NNE DURING THE DAY TODAY...RESULTING
IN INCREASING /MAINLY HIGH-BASED/ STRATOCU CLOUDS ACROSS THE SW HALF
OF THE CWA DURING THE MID TO LATE MORNING HOURS....AND DURING THE
AFTERNOON HOURS ACROSS THE SUSQUEHANNA`S MIDDLE AND WEST BRANCH
COMMUNITIES.
SREF/GEFS BOTH SHOW PWATS OF 1-2 SD ABOVE NORMAL SLIDING BACK INTO
WESTERN PA BY THE END OF THE DAY. SHORT RANGE OPERATIONAL MODELS
SHOW THE CHANCE FOR SHOWERS OVER MY FAR WESTERN ZONES BEFORE
NIGHT-FALL. SREF AND GEFS BOTH SHOW SMALL CHANCES FOR RAIN...THE
SREF BEING SLIGHTLY MORE AGGRESSIVE THAN THE GEFS. IT ALL POINTS TO
SCATTERED SHOWERS OR EVEN A THUNDERSTORM BY LATE DAY.
MDL DATA INDICATES THERE WILL BE VARYING AMTS OF CIRRUS ACROSS THE
AREA TODAY...SO HAVE KEPT MAX TEMPS A BIT LOWER THAN ENS MEAN
925MB TEMPS COULD SUPPORT WITH FCST HIGHS IN THE 70-75F RANGE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
NOT A LOT OF CHANGE FROM YESTERDAY. LOOKING AT A LARGE AREA OF
HIGH PRESSURE BUILDING ACROSS THE REGION...WITH A SLAB OF HOT
AIR FROM THE HIGH SOUTHERN PLAINS MOVING EASTWARD. WITH AN EML
AIRMASS IN PLACE...AND A TENDENCY TO CAP ANY CONVECTION...THINK
VERY LITTLE CHC OF RAIN WITH WARM FRONT LATE MONDAY NIGHT...AND
NOT MUCH IN THE WARM SECTOR ON WED...MAYBE A FEW STORMS LATE. DID
UP TEMPS SOME AND LOWER POPS A LITTLE.
HIGHEST CHC OF STORMS WILL BE ON THU...AS COLD FRONT NEARS.
COMPLEX FRONT...MORE LIKE 2 COLD FRONTS.
COLDER AIR FOR LATE IN THE WEEK...BUT THIS IS COMPLEX TOO.
EC RUNS HINT AT LESS HIGH PRESSURE MAY BUILD IN...AND UPPER LVL
TROUGH COULD TRY TO CLOSE OFF JUST EAST OF THIS AREA.
AS FAR AS LAKE EFFECT GOES...HARD TO SEE MUCH...PERHAPS SOME
LATER ON FRIDAY...AS COLD AIR DEEPENS...AND WINDS ALOFT BECOME
MORE NW.
THE MAIN STORY WILL BE THE HEAT. MANY SPOTS WILL LIKELY SEE
90 DEGREES...BETWEEN TUE AND LATE THU...AS PLUS 18 DEGREE AIR
OR HIGHER MOVES IN AT 850 MB ON WESTERLY FLOW. NAM STILL THE
WARMEST MODEL.
NOT SURE I BUY INTO THE HIGH DEWPOINTS ON TUE...ETC...WITH THIS
AIRMASS...GIVEN WHERE THE AIRMASS COMES FROM. WHILE THERE WILL BE
POTENTIAL FOR STRONG STORMS AT SOME POINT...THIS WILL LARGELY
DEPEND ON HOW MUCH LOW LVL MOISTURE WORKS INTO THE AREA. ANYWAY...
ENJOY THE LATE SUMMER WEATHER...AS WE MAKE UP FOR WHAT WAS A WET
EARLY SUMMER.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE OVER NE PA/SE NY WILL MOVE OFF THE NRN MID-ATLC
COAST BY 00Z. A DEVELOPING S-SWLY FLOW WILL LIFT A WARM FNT ACRS
THE AIRSPACE LATE TONIGHT INTO EARLY TUESDAY. A COLD FRONT WILL
APPROACH THE REGION FROM THE GREAT LAKES ON WED BEFORE CROSSING
THE AIRSPACE ON THURSDAY. HIGH PRESSURE WILL RETURN BEHIND THE
FRONT ON FRIDAY AND REMAIN IN CONTROL INTO THE WEEKEND.
IR SATL SHOWS SCT-BKN CIRRUS STREAMING SWD OVER PA EARLY THIS
MORNING. THERE ALSO APPEARS TO BE SOME LOWER CLOUDS DEVELOPING
OVER NRN VA AND THE WV/MD PNHDLES AS THE LLVL FLOW VEERS TO THE
ESE. THESE LOWER CLOUDS/VFR CIGS MAY TRY TO CREEP NORTH INTO
S-CNTRL PA EARLY THIS MORNING. SOME RADIATIONAL FOG MAY REDUCE VIS
AT BFD AND WILL HANDLE WITH AMDS GIVEN LOW CONFIDENCE. OTHERWISE
EXPECT VFR TO PREVAIL THRU THE EVE HOURS WITH SFC WINDS SHIFTING
FROM ENE TO SSE-SSW. MVFR CIGS ARE LKLY TO DEVELOP ACRS THE SERN
TERMINALS LATER TNT INTO EARLY TUESDAY.
OUTLOOK...
TUE...AM LOW CLOUDS SOUTH/EAST. ISOLD PM TSTM IMPACTS PSBL.
WED...SCT PM TSTM IMPACTS PSBL.
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...VFR. NO SIG WX.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT/STEINBUGL
NEAR TERM...FITZGERALD/LAMBERT
SHORT TERM...FITZGERALD/LAMBERT
LONG TERM...MARTIN
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
730 AM EDT MON SEP 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION TODAY AND LINGER INTO MID
WEEK. A COLD FRONT WILL ARRIVE OUT OF THE NORTH LATE IN THE
WEEK...USHERING IN COOLER AIR FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 730 AM EDT MONDAY... LITTLE CHANGE IN PAST SEVERAL HOURS
ALTHOUGH DENSE FOG HAS FORMED IN SOME OF THE MOUNTAIN VALLEYS.
DISSIPATION WILL INITIALLY BE SLOW... BUT BY MID MORNING VIRTUALLY
ALL THE FOG WILL BE GONE.
PREVIOUS DISCUSSIONS...
AS OF 430 AM EDT MONDAY...LITTLE HAS CHANGED SINCE THE LAST
UPDATE AS SATELLITE DIFFERENCE PRODUCT CONTINUES TO INDICATE
SCATTERED MID/HIGH CLOUDS ACROSS THE PIEDMONT REGIONS...AND
LOW/MID STRATUS IN THE MOUNTAIN VALLEYS. OTHERWISE...ADDITIONAL
FOG DEVELOPMENT HAS BEEN SLOW TO MATERIALIZE TO THIS POINT.
HOWEVER...STILL EXPECTING SOME ADDITIONAL COVERAGE BEFORE DAYBREAK
ESPECIALLY IN LOW LYING AREAS. AS FOR THE FCST...DID NOT MAKE ANY
CHANGES WITH THIS UPDATE.
AS OF 230 AM EDT MONDAY...PATCHY FOG BEGINNING TO DEVELOP ACROSS
THE REGION AT THIS TIME. DEVELOPMENT SHOULD CONTINUE AS
TEMPERATURES DROP ANOTHER DEGREE OR SO...HOWEVER NOT EXPECTING
DENSE FOG CRITERIA TO BE MET...THUS WILL NOT ISSUE DENSE FOG
ADVISORY AT THIS TIME. OTHERWISE...HIGH PRESSURE WILL CONTINUE TO
DOMINATE THE WEATHER ACROSS NORTHEAST GA AND THE CAROLINAS THROUGH
THE PERIOD. CENTRAL CONUS 590MB RIDGE WILL DRIFT EASTWARD DURING
THE DAY ON MONDAY WHILE SURFACE HIGH PRESSURE SHIFTS SOUTHWARD OUT
OF NEW ENGLAND. NORTHEASTERLY LOW LEVEL FLOW WILL VEER SOUTHERLY
DURING THE AFTERNOON HOURS AS THE SURFACE HIGH RELOCATES. MODEL
GUIDANCE DOES INDICATE MARGINAL INSTABILITY BUILDING ACROSS THE
REGION DURING THE PEAK HEATING HOURS...HOWEVER EXPECT SUBSIDENCE
FROM THE ABOVE MENTIONED RIDGE TO PREVAIL. WITH THAT SAID...WOULD
NOT BE SURPRISED TO SEE SOME FAIR WX CU DEVELOPMENT ACROSS MUCH OF
THE AREA. MOST OF THE REGION WILL REMAIN DRY WITH THE ONLY FCST
POPS BEING ALONG THE HIGH TERRAIN WHERE CHANCE POPS TAPER DOWN TO
SLIGHT CHANCE LEVELS IN THE FOOTHILLS AS UPSLOPE FLOW COMPONENT
PROVIDES LIFT IN AN OTHERWISE WEAKLY FORCED ENVIRONMENT. EXPECTING
ANY SHOWER OR THUNDERSTORM DEVELOPMENT IN THIS REGION TO BE ON A
DIURNAL TREND...THUS LOWERED POPS AFTER SUNSET. TEMPERATURES
DURING THE NEAR TERM PERIOD WILL REMAIN A FEW DEGREES ABOVE
NORMAL.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AT 225 AM EDT MONDAY...A DEEP LAYER RIDGE OF HIGH PRESSURE WILL BE
SITUATED OVER THE FORECAST AREA ON TUESDAY. MODEL SOUNDINGS ARE
STRONGLY CAPPED OUTSIDE OF THE MOUNTAINS. I LOWERED POPS A
HAIR...BUT I DID RETAIN SLIGHT CHANCE TO LOW END CHANCE POPS OVER
THE HIGH TERRAIN. I SUSPECT THAT EVEN THIS MIGHT BE TOO HIGH. MAX
TEMPS WILL RUN A FEW DEGREES ABOVE NORMAL. THE RIDGE WILL WEAKEN A
LITTLE ON WEDNESDAY AND BOTH THE GFS AND ECMWF GENERATE MORE PCPN
OVER THE MTNS. THIS SEEMS REASONABLE AND THE DAY SHIFT HAD THIS WELL
IN HAND WITH 30/40 POPS OVER THE MOUNTAINS AND SLIGHT CHANCE OR
LOWER POPS ACROSS THE PIEDMONT.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 250 AM MONDAY...A COLD FRONT IS STILL EXPECTED TO PUSH
ACROSS THE REGION SOMETIME ON THURSDAY. AS THE PREVIOUS SHIFT
MENTIONED...THE FORCING ALONG THE FRONT ISN/T THAT STRONG WITH WEAK
WIND SHEAR AND MODEST INSTABILITY. LOW CHANCE POPS WERE
RETAINED...BUT THERE IS NO INDICATION THAT ANY KIND OF ORGANIZED
SEVERE THREAT WILL ACCOMPANY THE FRONT. CONVERGENCE WILL SHIFT SOUTH
OF THE REGION FRIDAY AND THROUGH THE WEEKEND. TEMPERATURES WILL
GRADUALLY COOL AND THE AIRMASS WILL BECOME DRIER AS HIGH PRESSURE OF
CANADIAN ORIGINS PUSHES INTO THE FORECAST AREA.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AT KCLT...NO CHANGES FROM PREVIOUS FORECAST. VFR CONDITIONS WILL
PREVAIL THROUGH THE TAF PERIOD AS HIGH PRESSURE DOMINATES. UPPER
LEVEL RIDGE WILL CONTINUE TO SHIFT EAST THROUGH THE PERIOD WHILE
SURFACE HIGH PRESSURE LOCATED OVER NEW ENGLAND EXTENDS TO THE
SOUTHEAST. AS THE PERIPHERY OF THE RIDGE LOWERS INTO THE MID
ATLANTIC STATES INTRODUCED LIGHT SOUTHERLY WINDS LATE IN THE PERIOD.
OTHERWISE... THERE WILL BE ENOUGH INSTABILITY ACROSS THE PIEDMONT TO
PRODUCE SOME FAIR WX CU DURING THE PEAK HEATING HOURS. OTHER THAN
THAT SHOULD BE A QUIET FORECAST PERIOD.
ELSEWHERE...IFR FOG AT KAVL UNTIL APPROXIMATELY 14Z. OTHERWISE...
AFTER INITIAL PATCHY FOG BURNS OFF BEYOND SUNRISE... CONDITIONS WILL
IMPROVE TO VFR LEVELS AT ALL SITES AND REMAIN THERE THROUGH THE
DAY. LATEST HRRR AND 4KMWRF INDICATE THAT THE POSSIBILITY REMAINS
FOR SCATTERED SHOWERS ALONG THE MOUNTAINS AS UPSLOPE FLOW AIDS
WEAKLY FORCED ENVIRONMENT...HOWEVER STILL NOT CONFIDENT ENOUGH TO
ADD AT KAVL AT THIS TIME. DID INCLUDE MVFR RESTRICTIONS ON TUESDAY
MORNING AT KAND AND KHKY WHILE IFR RESTRICTIONS ARE HIGHLIGHTED AT
KAVL FOR FOG. WINDS THROUGH THE PERIOD SHOULD REMAIN GENERALLY
LIGHT AND WILL VEER SOUTHERLY DURING THE AFTERNOON/EVENING HOURS.
OUTLOOK...WEAK HIGH PRESSURE WILL REMAIN IN PLACE THROUGH MID WEEK
WITH WITH AFTERNOON/EVENING SHOWERS AND STORMS POSSIBLE. A STRONGER
FRONT WILL MOVE OVER THE AREA LATE IN THE WEEK.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-11Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 95% HIGH 100% HIGH 100% HIGH 91%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 87%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% 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...MCAVOY
NEAR TERM...CDG
SHORT TERM...MCAVOY
LONG TERM...MCAVOY
AVIATION...CDG
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1221 AM CDT MON SEP 9 2013
.UPDATE...
AVIATION DISCUSSION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.
A LOT OF FORECAST UNCERTAINTY AT THIS TIME. 18Z MODEL DATA IS MUCH
MORE BULLISH WITH LLJ BEING DISPLACED FURTHER EAST ACROSS THE
ABERDEEN CWA. THE HRRR DOES INDICATE AN INCREASE IN ELEVATED
CONVECTION DURING THE MID TO LATE EVENING...AND GIVEN MODEL
CHANGES WILL ACCEPT THAT AND INCREASE POPS A LITTLE. FURTHER WEST
IT APPEARS THERE WILL STILL BE SOME OPPORTUNITY FOR AN MCS OR TWO
COMING OFF THE HIGH PLAINS AND EAST ACROSS THE CWA OVERNIGHT. HRRR
CONTINUES TO BE QUITE BULLISH WITH THIS PROGNOSTICATION AND THUS
WILL MAINTAIN RELATIVELY HIGH POPS. TEMPERATURES ARE OKAY. UPDATES
OUT SOON.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...THROUGH TUESDAY AM
WHILE PRECIPITATION HAS DISSIPATED...CONVECTIVE DEBRIS CONTINUES
TO MUDDY WHAT WAS ALREADY A COMPLEX FORECAST. DAYTIME HEATING IS
GREATEST ACROSS NORTHWEST COUNTIES...UNDER WHICH THE CAP IS THE
WEAKEST...WITH H7 TEMPERATURES ONLY BETWEEN +11 AND +12C. THE
MAIN SHORTWAVE IS STILL FAR TO THE WEST...WITH WARM ADVECTION
ALOFT. THERE IS STILL THE POTENTIAL FOR A SURFACE BASED STORM OR
TWO TO FORM ALONG THE ND/SD BORDER AND PUSH EAST...WEAKENING AS H7
TEMPERATURES WARM AND IT ENCOUNTERS MORE CLOUDY/LESS UNSTABLE AIR
IN THE EAST...AND IN FACT SOME OF THE HIGH RES GUIDANCE HINTS AT
SUCH. OTHERWISE...CONVECTION TODAY WILL BE LIMITED TO ELEVATED
WEAK STORMS OVER CENTRAL/WESTERN SD WHERE H7 WARM ADVECTION
STEEPENS MID LEVEL LAPSE RATES...AND SOME OF THE HIGH RES GUIDANCE
HAS SUGGESTED THIS OUTCOME. OF GREATEST CONCERN CONTINUES TO BE AS
THE SHORTWAVE APPROACHES...AND TEMPERATURES ALOFT COOL...WITH
INCREASING LOW LEVEL JET SUPPORT. STORMS IN THIS ENVIRONMENT FAVOR
SLOW EAST/NORTHEAST STORM MOTION...WITH NORTH DAKOTA GETTING THE
BEST COVERAGE...STILL LOOKING LIKE SCATTERED COVERAGE THIS SIDE OF
THE BORDER. GIVEN THE HEAVY RAIN LAST NIGHT IN CORSON
COUNTY...WENT FOR A FLASH FLOOD WATCH. STORMS PUSH EAST AND
DISSIPATE MONDAY AM. THE FRONT IS NOW PROGGED TO PUSH ALL THE WAY
THROUGH THE CWA BY MID DAY...WITH THE CAP IN PLACE FARTHER EAST
...PRE-FRONTAL CONVECTIVE ACTIVITY APPEARS UNLIKELY IN THE CWA. IN
THE POST FRONTAL ENVIRONMENT...COOLING ALOFT AND PLENTY OF DAYTIME
HEATING SUGGEST A CONTINUED THREAT FOR STORMS...WITH STRAIGHT
LINE HODOGRAPHS. MAIN QUESTION REVOLVES AROUND INSTABILITY AS WILL
SEE LOW LEVEL DRY AIR ADVECTION AS WELL.
.LONG TERM...TUESDAY THROUGH SUNDAY
BULK OF THE EXTENDED PERIOD LOOKS DRY AT THIS POINT. ON TUESDAY
DRIER AIR WILL BE FILTERING INTO THE REGION WITH NORTHWEST FLOW
ALOFT. CONDITIONS LOOK DRY ALL THE WAY THROUGH THE FIRST HALF OF
FRIDAY AS SFC HIGH PRESSURE BEGINS BUILDING SOUTH INTO THE AREA BY
THURSDAY. COOLER AIR ARRIVES ON THURSDAY AS WELL...SO THE 80S FOR
HIGHS ON TUESDAY AND WEDNESDAY WILL BE REPLACED BY 70S ON THURSDAY
AND FRIDAY. THE ONLY REAL SHOT FOR PRECIP DURING THE EXTENDED
FORECAST IS FRIDAY NIGHT THROUGH SATURDAY NIGHT AS SHORTWAVE
ENERGY MOVES INTO THE NORTHERN PLAINS AROUND THE UPPER RIDGE.
MODELS HAVE TRENDED FURTHER SOUTH WITH THIS FEATURE INITIALLY ON
FRIDAY...WITH MODELS SHOWING MOST QPF ACROSS NEBRASKA AND SOUTHERN
SOUTH DAKOTA. FAIRLY GOOD AGREEMENT ACTUALLY IN BRINGING PRECIP
INTO THE EASTERN CWA DURING THE DAY SATURDAY. FOR NOW HAVE
ACCEPTED ALLBLEND POPS WHICH HAVE 30S/40S FOR POPS FRIDAY NIGHT
THROUGH SATURDAY WHICH LOOKS GOOD AT THIS POINT.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
A MIX OF CONDITIONS IS EXPECTED ACROSS THE REGION THROUGH MONDAY.
A MIX OF VFR/MVFR CIGS IS EXPECTED AT KMBG/KPIR AS STORMS MOVE
THROUGH THE AREA EARLY THIS MORNING. FURTHER EAST AT KATY AN IFR
DECK OF CLOUDS WILL LIKELY PERSIST THROUGH THE MORNING HOURS ON
MONDAY...ALONG WITH MVFR FOG. KABR WILL LIKELY SHARE IN SOME IFR
CIGS MVFR VSBYS OVERNIGHT...ALONG WITH SOME STORMS LATE. ANY
STORMS COULD PRODUCE PERIODS OF IFR CONDITIONS WHEN THEY MOVE
THROUGH.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...FLASH FLOOD WATCH UNTIL 6 AM MDT MONDAY FOR CORSON.
MN...NONE.
&&
$$
UPDATE...TDK
SHORT TERM...CONNELLY
LONG TERM...TMT
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1236 PM CDT MON SEP 9 2013
.UPDATE...FOR 18Z AVIATION DISCUSSION.
&&
.AVIATION...18Z AVIATION DISCUSSION.
UNCERTAINTIES...MVFR TO IFR FOG DEVELOPMENT CKV AND CSV. ISO MAINLY DIURNAL
DRIVEN SHWRS/TSTMS ARE POSSIBLE THRU 10/02Z...BUT WITH LOCATION DEVELOPMENT
SO UNCERTAIN...WILL NOT MENTION IN TAFS. EXPECT SCT CU TO SCT/BKN CI THRU
10/02Z THOUGH. SCT/BKN CI WILL CONTINUE THRU 10/15Z...BUT PER USUAL LOW
LEVEL MOISTURE POOLING POTENTIAL...MVFR FOG STILL POSSIBLE CKV AND CSV...
WITH TYPICAL TEMPO IFR POSSIBLE CSV...PER MAX RADITIONAL COOLING POTENTIAL
AND LIGHT WINDS. WITH UPPER LEVEL RIDGING INFLUENCES...EXPECT ONLY SCT CU
TO SCT/BKN CI FROM 10/15Z-10/18Z.
&&
.PREV DISCUSSION... /ISSUED 607 AM CDT MON SEP 9 2013/
AVIATION UPDATE...FOR 12Z TAF PACKAGE...
SHORTWAVE IS PRODUCING WEAK STORMS IN VICINITY OF KCKV AND KBNA
THIS MORNING AT TAF ISSUANCE. RADAR TRENDS SHOW MOSTLY JUST RAIN.
MAY SEE SOME FURTHER DEVELOPMENT THIS MORNING AS AREA OF LIFT GETS
CLOSER BUT MODELS DO NOT HAVE THIS FEATURE REACHING FAR ENOUGH
SOUTHEAST TO IMPACT KBNA SO LEFT TEMPO GROUP AND STUCK WITH JUST
VCSH. OTHERWISE...VFR EXPECTED.
PREV DISCUSSION... /ISSUED 257 AM CDT MON SEP 9 2013/
DISCUSSION...
WEAK VERY SUBTLE SURFACE BOUNDARY EXTENDS FROM SAINT LOUIS DOWN
THROUGH FAR WESTERN KENTUCKY INTO SOUTHERN MIDDLE TENNESSEE. WEAK
SHORT WAVE AT THE MID LEVELS OVER FAR WESTERN KENTUCKY CAN BE SEEN
IN 00Z EURO AT 06Z AND TO SOME EXTENT IN THE LASTEST RUC LOOP OF 700
MBAR COLD TEMP AXIS. AGAIN VERY SUBTLE FEATURES. ISOLATED CONVECTION
DEVELOPED JUST AFTER MIDNIGHT IN FAR NORTHWEST MIDDLE TENNESSEE
AND HAS MOVED LITTLE LAST COUPLE OF HOURS. 500 MBAR HIGH TO OUR
WEST WILL WORK EASTWARD TODAY KEEPING SUBSIDENCE ACROSS THE AREA
AND WITH LITTLE IN THE WAY OF FORCING SO AM EXPECTING TO SEE ONLY
ISOLATED CONVECTION ONCE AGAIN. THINK AREAS WEST OF INTERSTATE 65
MIGHT BE FAVORED BUT AGAIN LOW POPS. SURFACE BOUNDARY WILL LIFT
NORTH TODAY WHILE SHORT WAVE DAMPS OUT. THIS WILL PLACE MID STATE
PRETTY MUCH IN THE GRIPS OF UPPER LEVEL RIDGING WITH LOW POP
CHANCES FOR CONVECTION BOTH DURING THE DAY AND NOCTURNALLY AT
LEAST THROUGH WEDNESDAY. BY THURSDAY A SURFACE FRONT WILL BE
MAKING ITS WAY SOUTHWARD FROM GREAT LAKES REGION AND THIS WILL
INCREASE POPS FOR THURSDAY AND THURSDAY NIGHT. WITH ALL THE
RIDGING IN PLACE OF RECENT DAYS AND CONTINUED OFF CONTINENT WIND
FLOW I JUST DONT SEE MUCH IN THE WAY OF MOISTURE TO FEED THIS
SOUTH BOUND SYSTEM SO AM EXPECTING RAINFALL AMOUNTS TO LIKELY BE
LOW. FRONT GETS SOUTH OF MID STATE ON FRIDAY WITH 1024 SURFACE
HIGH CENTERED OVER LAKE SUPERIOR. COOLER AND MORE SEASONABLE TEMPS
WILL FOLLOW FRONTAL PASSAGE. SURFACE HIGH WILL RIDGE DOWN ACROSS
THE MID STATE THROUGH THE WEEKEND.
AS FOR TEMPS...MET IS RUNNING 2 TO 4 DEGREES COOLER THAN MAV FOR
DAYTIME HIGHS THROUGH WEDNESDAY AND KEEPS TRYING TO GO TOWARD
CLIMATOLOGY WHILE MAV IS WANTING TO KEEP THINGS MORE HEATED. I
BASICALLY KNOCKED ONE TO TWO DEGREES OFF THE MAV FOR DAYTIME HIGHS
THROUGH WEDNESDAY OR CLOSER TO AVERAGE OF THE TWO MODELS. BOTH MET
AND MAV ARE CLOSE ON NIGHTTIME LOWS THROUGH WEDNESDAY SO I FOLLOWED.
FOLLOWING FRONTAL PASSAGE EXPECT HIGHS ON FRIDAY TO BE A GOOD 10
DEGREES COOLER THAN WHAT WE HAVE BEEN SEEING. TEMPS FRIDAY THROUGH
THE WEEKEND WILL BE IN THE LOW TO MID 80S WITH MID AND UPPER 70S
ALONG THE UPPER CUMBERLAND.
BOYD
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
607 AM CDT MON SEP 9 2013
.AVIATION UPDATE...FOR 12Z TAF PACKAGE...
SHORTWAVE IS PRODUCING WEAK STORMS IN VICINITY OF KCKV AND KBNA
THIS MORNING AT TAF ISSUANCE. RADAR TRENDS SHOW MOSTLY JUST RAIN.
MAY SEE SOME FURTHER DEVELOPMENT THIS MORNING AS AREA OF LIFT GETS
CLOSER BUT MODELS DO NOT HAVE THIS FEATURE REACHING FAR ENOUGH
SOUTHEAST TO IMPACT KBNA SO LEFT TEMPO GROUP AND STUCK WITH JUST
VCSH. OTHERWISE...VFR EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 257 AM CDT MON SEP 9 2013/
DISCUSSION...
WEAK VERY SUBTLE SURFACE BOUNDARY EXTENDS FROM SAINT LOUIS DOWN
THROUGH FAR WESTERN KENTUCKY INTO SOUTHERN MIDDLE TENNESSEE. WEAK
SHORT WAVE AT THE MID LEVELS OVER FAR WESTERN KENTUCKY CAN BE SEEN
IN 00Z EURO AT 06Z AND TO SOME EXTENT IN THE LASTEST RUC LOOP OF 700
MBAR COLD TEMP AXIS. AGAIN VERY SUBTLE FEATURES. ISOLATED CONVECTION
DEVELOPED JUST AFTER MIDNIGHT IN FAR NORTHWEST MIDDLE TENNESSEE
AND HAS MOVED LITTLE LAST COUPLE OF HOURS. 500 MBAR HIGH TO OUR
WEST WILL WORK EASTWARD TODAY KEEPING SUBSIDENCE ACROSS THE AREA
AND WITH LITTLE IN THE WAY OF FORCING SO AM EXPECTING TO SEE ONLY
ISOLATED CONVECTION ONCE AGAIN. THINK AREAS WEST OF INTERSTATE 65
MIGHT BE FAVORED BUT AGAIN LOW POPS. SURFACE BOUNDARY WILL LIFT
NORTH TODAY WHILE SHORT WAVE DAMPS OUT. THIS WILL PLACE MID STATE
PRETTY MUCH IN THE GRIPS OF UPPER LEVEL RIDGING WITH LOW POP
CHANCES FOR CONVECTION BOTH DURING THE DAY AND NOCTURNALLY AT
LEAST THROUGH WEDNESDAY. BY THURSDAY A SURFACE FRONT WILL BE
MAKING ITS WAY SOUTHWARD FROM GREAT LAKES REGION AND THIS WILL
INCREASE POPS FOR THURSDAY AND THURSDAY NIGHT. WITH ALL THE
RIDGING IN PLACE OF RECENT DAYS AND CONTINUED OFF CONTINENT WIND
FLOW I JUST DONT SEE MUCH IN THE WAY OF MOISTURE TO FEED THIS
SOUTH BOUND SYSTEM SO AM EXPECTING RAINFALL AMOUNTS TO LIKELY BE
LOW. FRONT GETS SOUTH OF MID STATE ON FRIDAY WITH 1024 SURFACE
HIGH CENTERED OVER LAKE SUPERIOR. COOLER AND MORE SEASONABLE TEMPS
WILL FOLLOW FRONTAL PASSAGE. SURFACE HIGH WILL RIDGE DOWN ACROSS
THE MID STATE THROUGH THE WEEKEND.
AS FOR TEMPS...MET IS RUNNING 2 TO 4 DEGREES COOLER THAN MAV FOR
DAYTIME HIGHS THROUGH WEDNESDAY AND KEEPS TRYING TO GO TOWARD
CLIMATOLOGY WHILE MAV IS WANTING TO KEEP THINGS MORE HEATED. I
BASICALLY KNOCKED ONE TO TWO DEGREES OFF THE MAV FOR DAYTIME HIGHS
THROUGH WEDNESDAY OR CLOSER TO AVERAGE OF THE TWO MODELS. BOTH MET
AND MAV ARE CLOSE ON NIGHTTIME LOWS THROUGH WEDNESDAY SO I FOLLOWED.
FOLLOWING FRONTAL PASSAGE EXPECT HIGHS ON FRIDAY TO BE A GOOD 10
DEGREES COOLER THAN WHAT WE HAVE BEEN SEEING. TEMPS FRIDAY THROUGH
THE WEEKEND WILL BE IN THE LOW TO MID 80S WITH MID AND UPPER 70S
ALONG THE UPPER CUMBERLAND.
BOYD
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TB12
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
257 AM CDT MON SEP 9 2013
.DISCUSSION...
WEAK VERY SUBTLE SURFACE BOUNDARY EXTENDS FROM SAINT LOUIS DOWN
THROUGH FAR WESTERN KENTUCKY INTO SOUTHERN MIDDLE TENNESSEE. WEAK
SHORT WAVE AT THE MID LEVELS OVER FAR WESTERN KENTUCKY CAN BE SEEN
IN 00Z EURO AT 06Z AND TO SOME EXTENT IN THE LASTEST RUC LOOP OF 700
MBAR COLD TEMP AXIS. AGAIN VERY SUBTLE FEATURES. ISOLATED CONVECTION
DEVELOPED JUST AFTER MIDNIGHT IN FAR NORTHWEST MIDDLE TENNESSEE
AND HAS MOVED LITTLE LAST COUPLE OF HOURS. 500 MBAR HIGH TO OUR
WEST WILL WORK EASTWARD TODAY KEEPING SUBSIDENCE ACROSS THE AREA
AND WITH LITTLE IN THE WAY OF FORCING SO AM EXPECTING TO SEE ONLY
ISOLATED CONVECTION ONCE AGAIN. THINK AREAS WEST OF INTERSTATE 65
MIGHT BE FAVORED BUT AGAIN LOW POPS. SURFACE BOUNDARY WILL LIFT
NORTH TODAY WHILE SHORT WAVE DAMPS OUT. THIS WILL PLACE MID STATE
PRETTY MUCH IN THE GRIPS OF UPPER LEVEL RIDGING WITH LOW POP
CHANCES FOR CONVECTION BOTH DURING THE DAY AND NOCTURNALLY AT
LEAST THROUGH WEDNESDAY. BY THURSDAY A SURFACE FRONT WILL BE
MAKING ITS WAY SOUTHWARD FROM GREAT LAKES REGION AND THIS WILL
INCREASE POPS FOR THURSDAY AND THURSDAY NIGHT. WITH ALL THE
RIDGING IN PLACE OF RECENT DAYS AND CONTINUED OFF CONTINENT WIND
FLOW I JUST DONT SEE MUCH IN THE WAY OF MOISTURE TO FEED THIS
SOUTH BOUND SYSTEM SO AM EXPECTING RAINFALL AMOUNTS TO LIKELY BE
LOW. FRONT GETS SOUTH OF MID STATE ON FRIDAY WITH 1024 SURFACE
HIGH CENTERED OVER LAKE SUPERIOR. COOLER AND MORE SEASONABLE TEMPS
WILL FOLLOW FRONTAL PASSAGE. SURFACE HIGH WILL RIDGE DOWN ACROSS
THE MID STATE THROUGH THE WEEKEND.
AS FOR TEMPS...MET IS RUNNING 2 TO 4 DEGREES COOLER THAN MAV FOR
DAYTIME HIGHS THROUGH WEDNESDAY AND KEEPS TRYING TO GO TOWARD
CLIMATOLOGY WHILE MAV IS WANTING TO KEEP THINGS MORE HEATED. I
BASICALLY KNOCKED ONE TO TWO DEGREES OFF THE MAV FOR DAYTIME HIGHS
THROUGH WEDNESDAY OR CLOSER TO AVERAGE OF THE TWO MODELS. BOTH MET
AND MAV ARE CLOSE ON NIGHTTIME LOWS THROUGH WEDNESDAY SO I FOLLOWED.
FOLLOWING FRONTAL PASSAGE EXPECT HIGHS ON FRIDAY TO BE A GOOD 10
DEGREES COOLER THAN WHAT WE HAVE BEEN SEEING. TEMPS FRIDAY THROUGH
THE WEEKEND WILL BE IN THE LOW TO MID 80S WITH MID AND UPPER 70S
ALONG THE UPPER CUMBERLAND.
BOYD
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 92 71 93 71 / 20 10 20 20
CLARKSVILLE 91 69 92 69 / 20 10 20 20
CROSSVILLE 85 64 86 65 / 20 10 20 20
COLUMBIA 93 69 93 70 / 20 10 20 20
LAWRENCEBURG 93 67 92 68 / 20 10 20 20
WAVERLY 92 68 93 69 / 20 10 20 20
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
BOYD
01
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
854 PM CDT TUE SEP 10 2013
.UPDATE...
A DOWNWARD TREND TO WHAT HAS OCCURRED THE PAST FEW EVENINGS IS
EXPECTED TO CONTINUE INTO LATE TONIGHT...WITH LIGHT STREAMER
SHOWERS EXPECTED TO REDEVELOP IN THE OVERNIGHT HOURS INTO
DAYBREAK. THIS IS REINFORCED BY THE RECENT RUC AND HRRR RUNS. WILL
DROP CHANCES TO 20 PERCENT OR LESS AND REMOVE THUNDER FOR ALL BUT
THE SOUTHEAST COUNTIES AROUND DAYBREAK. A FEW LIGHTNING STRIKES
MAY DEVELOP THIS EVENING NEAR THE RIO GRANDE...BUT EXPECT THEM TO
BE ACROSS THE BORDER WHERE TERRAIN FEATURES WILL CONTRIBUTE TO
CELL GROWTH.
&&
.PREV DISCUSSION... /ISSUED 646 PM CDT TUE SEP 10 2013/
AVIATION...
ISOLD SHRA/TSRA SLOWLY END THIS EVENING...HOWEVER LINGERS OVER THE
RIO GRANDE OVERNIGHT. ISOLD TO SCT SHRA/TSRA EXPECTED WEDNESDAY
WITH GREATEST COVERAGE OVER THE RIO GRANDE. HAVE MENTIONED TEMPO
-RA FOR KDRT OVERNIGHT INTO EARLY WEDNESDAY. OTHERWISE...NO
MENTION IN TAFS DUE TO LOW PROBABILITY. VFR SKIES THIS EVENING
LOWER TO MVFR/IFR CIGS/VSBYS OVERNIGHT INTO EARLY WEDNESDAY
MORNING. DUE TO MOIST AIRMASS...PATCHY FG WITH VLIFR VSBYS IS
POSSIBLE. CIGS LIFT TO VFR AND BR/FG DISSIPATE BY MIDDAY. E TO SE
WINDS 7 TO 12 KTS DECREASE TO LESS THAN 6 KTS OVERNIGHT AND THEN
INCREASE TO 7 TO 12 KTS LATE WEDNESDAY AFTERNOON. DOWNDRAFT WIND
GUSTS TO 35 KTS ARE POSSIBLE IN AND NEAR SHRA/TSRA.
PREV DISCUSSION... /ISSUED 302 PM CDT TUE SEP 10 2013/
SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...
THIS AFTERNOON SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE
OCCURRING ACROSS MUCH OF SOUTH CENTRAL TEXAS AS DAYTIME HEATING
INTERACTED WITH THE TROPICAL AIRMASS. THE AWIPS TOTAL BLENDED PWAT
PRODUCT STILL DEPICTED VALUES RANGING FROM 1.8 INCHES NORTH TO 2.0
INCHES SOUTH. THESE VALUES ARE ASSOCIATED WITH LOCALLY HEAVY
RAINFALL. THE CONVECTION WILL DIMINISH IN AREA COVERAGE OVERNIGHT
WITH THE LOSS OF HEATING. HOWEVER ISOLATED SHOWERS AND THUNDERSTORMS
WILL CONTINUE OVER THE RIO GRANDE PLAINS AFTER MIDNIGHT WHERE
DEEP TROPICAL MOISTURE WILL PERSIST. LOWS WILL BE SLIGHTLY ABOVE
SEASONAL NORMALS. AN UPPER LEVEL RIDGE OVER THE OHIO VALLEY WILL
BUILD TO THE SOUTHWEST INTO TEXAS ON WEDNESDAY KEEPING THE DEEPER
MOISTURE AXIS WEST OVER THE RIO GRANDE PLAINS. THUS CONVECTIVE
COVERAGE ON WEDNESDAY WILL RANGE FROM ISOLATED NORTHEAST TO
SCATTERED WEST. CLOUDS AND PCPN WILL KEEP AFTERNOON HIGHS AROUND
NORMAL ON WEDNESDAY. SHOWERS AND THUNDERSTORMS WILL END BY
MIDNIGHT WITH LOWS WEDNESDAY NIGHT SIMILAR TO WHAT IS EXPECTED
TONIGHT.
LONG TERM (THURSDAY THROUGH TUESDAY)...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR GENERALLY
ALONG AND SOUTH OF HIGHWAY 90 ON THURSDAY AS THE EASTERLIES ENHANCE
CONVECTION ON THE SEA-BREEZE BOUNDARY. FRIDAY IS EXPECTED TO BE DRY
AS THE UPPER HIGH BRIEFLY BECOMES CENTERED OVER NORTH TEXAS. ALL
EYES WILL BE ON THE GULF OF MEXICO AND THE BAY OF CAMPECHE OVER
THE WEEKEND. A TROF OF LOW PRESSURE CURRENTLY LOCATED OVER THE
CARIBBEAN NEAR BELIZE WILL MOVE WESTWARD INTO THE BAY OF CAMPECHE
BY THURSDAY. A TROPICAL DEPRESSION IS EXPECTED TO FORM OVER THE
SOUTHWESTERN GULF LATER THIS WEEK AND HAS A HIGH CHANCE OF BECOMING
A TROPICAL CYCLONE OVER THE WEEKEND. THE TRACK OF THIS SYSTEM WILL
HAVE A DIRECT IMPACT ON THE FORECAST FOR SOUTH CENTRAL TEXAS. ATTM
THE MODEL CONSENSUS IS FOR THE SYSTEM TO MOVE WESTWARD MAKING LANDFALL
IN MEXICO ON MONDAY NEAR TAMPICO. THE 12Z GFS IS THE FURTHEST NORTH
WITH THE TRACK...MOVING ONSHORE SOUTH OF BROWNSVILLE...THEN MOVING
NORTHWEST UP THE RIO GRANDE. IN ANY EVENT INCREASING TROPICAL MOISTURE
WITH THIS SYSTEM WILL LEAD TO INCREASING POPS WITH THE POTENTIAL
FOR HEAVY RAINFALL ACROSS SOUTH CENTRAL TEXAS EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 74 95 74 95 74 / 10 10 - 10 -
AUSTIN BERGSTROM INTL AIRPORT 70 94 70 94 70 / 10 10 10 10 -
NEW BRAUNFELS MUNI AIRPORT 70 94 70 94 69 / 10 20 10 20 -
BURNET MUNI AIRPORT 70 92 71 93 71 / 10 10 - 10 -
DEL RIO INTL AIRPORT 75 90 73 92 73 / 20 30 10 20 -
GEORGETOWN MUNI AIRPORT 71 94 71 94 72 / 10 10 - 10 -
HONDO MUNI AIRPORT 73 93 72 93 71 / 20 20 10 10 -
SAN MARCOS MUNI AIRPORT 70 95 71 95 70 / 10 10 10 10 -
LA GRANGE - FAYETTE REGIONAL 75 95 75 95 75 / 10 20 10 10 10
SAN ANTONIO INTL AIRPORT 75 94 75 93 74 / 20 20 10 10 -
STINSON MUNI AIRPORT 76 94 76 94 75 / 20 20 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...18
PUBLIC SERVICE/DATA COLLECTION...33
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
137 PM EDT MON SEP 9 2013
.SYNOPSIS...
A WEAK COOL FRONT WILL DRIFT SOUTH INTO THE CAROLINAS TODAY AND
GRADUALLY DISSIPATE THIS EVENING. HIGH PRESSURE BUILDING NORTH OF
THE AREA WILL WEDGE SOUTH ALONG THE APPALACHIANS THIS MORNING
BEFORE SLIDING QUICKLY EAST AND OFFSHORE THE MID ATLANTIC COAST
THIS AFTERNOON. HIGH PRESSURE ALOFT SLIDES EAST INTO THE AREA BY
TUESDAY BRINGING A RETURN TO MORE SUMMERLIKE WEATHER FOR MID WEEK
AHEAD OF A STRONG COLD FRONT THAT ARRIVES ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1140 AM EDT MONDAY... INCREASED CLOUD COVER FOR THIS
AFTERNOON AND LOWERED TEMPERATURES. CLOUDS AND LOW LEVEL COOL POOL
ARE BANKING UP AGAINST THE BLUE RIDGE RIDGE WITH CU FIELD
DEVELOPING ALONG SOUTHERN PORTIONS OF CWA WHERE THERE WAS SOME
MORNING SUNSHINE. SHAPED THE AFTERNOON POPS TOWARDS THE HRRR WITH
CONVECTION ACROSS HIGHER TERRAIN AND SPOTTY ACTIVITY IN THE EAST.
MORE ADJUSTMENTS THIS AFTERNOON...
AS OF 910 AM EDT MONDAY...
WITH THIS MORNING RNK 12Z/8AM SOUNDING SHOWING SHALLOW MOISTURE
UP TO 870 MB...EXPECT CLOUD COVER TO PERSIST FOR A COUPLE OF HOURS
THIS MORNING WITH THE WEAK FRONT AND LOW LEVEL WEDGE. WITH THIS
RICH CLOUD COVER...LOWERED TEMPERATURES FOR THIS MORNING INTO
THIS AFTERNOON. ISOLATED TO SCATTERED POPS SUPPORTED BY
ECMWF...GFS NAM...MAINLY ACROSS THE HIGHER TERRAIN. 06Z RNK WRF
ARW PLACED THE FOCUS OF CONVECTION ACROSS THE NORTHWEST
MOUNTAINS. WILL SHAPE POPS AND ISC GRIDS AS MORNING PROGESSES.
AS OF 230 AM EDT MONDAY...
FORECAST REMAINS RATHER UNCERTAIN OVER THE NEXT 24 HOURS WITH
A WEAK FRONT DROPPING TO THE SOUTH THIS MORNING AND A LOW LEVEL
WEDGE DEVELOPING BEHIND THE BOUNDARY ALONG THE MOUNTAINS INTO
THIS AFTERNOON. KEY IS WHETHER OR NOT ANY LOW CLOUDS DEVELOP
WITHIN THE LOW LEVEL COOL POOL THIS MORNING AND BANK UP ALONG THE
BLUE RIDGE LONGER THAN EXPECTED DESPITE HIGH PRES EXITING OFF TO
THE NE AFTER MIDDAY. MODELS CONTINUE TO SUGGEST THIS SCENARIO WITH
ONGOING ISOLATED -SHRA FADING OUT EAST BY DAYBREAK ONLY TO HAVE
LOW CLOUDS SPILL BACK WEST AIDED BY WEAK UPSLOPE. THEREFORE HAVE
TRENDED CLOUDIER EARLY ON EASTERN HALF WITH LESS CLOUDS WEST
WHERE EARLY FOG/STRATUS MORE PREVALENT.
LOW LEVEL FLOW WILL GRADUALLY VEER AROUND TO THE SOUTH/SW FROM
WEST TO EAST THIS AFTERNOON AS THE HIGH EXITS WITH INCREASING
WEAK MOISTURE CONVERGENCE FAR WEST. HOWEVER MAY STILL SEE A WEAK
RESIDUAL WEDGE HANG IN OUT EAST PER SUBTLE SE FLOW AND LINGERING
STABILITY OFF GUIDANCE. THIS SHOULD KEEP ANY ADDED SHRA CONFINED
TO THE MOUNTAINS WHERE MODELS DEPICT BEST AXIS OF THETA-E AND
DECENT CAPES AHEAD OF PERHAPS A WEAK MID LEVEL WAVE SPILLING IN
FROM THE NW LATE. THIS COULD BE ENOUGH TO SPARK MAINLY ISOLATED
SHRA/TSRA BUT IFFY GIVEN LACK OF MUCH LOW LEVEL FOCUS...BUILDING
5H HEIGHTS FROM THE WEST AND ONLY SHALLOW MOISTURE. THUS STAYING
WITH 20/30 POPS WEST WHICH MESHES BEST WITH THE LATEST ENSEMBLES
AND DRY EAST WHERE CLOUDS MAY LINGER. HIGH TEMPS TRICKY PENDING
TIMING OF MORE INSOLATION EAST AND WEAK VEERING FLOW FOLLOWING A
WARM START. IF CLOUDS LOCK IN ACROSS THE NE THEN MAY BE TOUGH TO
REACH 80...WHILE ELSW COULD ZOOM UP ESPCLY WEST GIVEN WEAK
DOWNSLOPING SO BUMPED UP HIGHS THERE AND TRIMMED BACK OUT EAST.
UPPER RIDGE OVER THE MIDWEST SHIFTS EAST OVERNIGHT AS THE SURFACE
HIGH EXITS FARTHER EAST WHILE ELONGATING BACK INLAND TO OVER THE
CAROLINAS LATE. THIS SHOULD ALLOW FOR A WEAK SUBSIDENCE REGIME TO
LINGER WITH ANY RESIDUAL EVENING SHRA FROM EARLIER OUTFLOW...AND
POSSIBLY ISOLATED SHRA ACROSS THE FAR NW WITH ANY FAINT IMPULSE
SPILLING SE OVERNIGHT. OTRW PC NORTH/WEST TO CLEAR ELSW WITH
THINGS A BIT MORE MUGGY GIVEN LOWS MAINLY IN THE 60S.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EDT MONDAY...
UPPER RIDGE CONTINUES TO BUILD OVER THE REGION ON TUESDAY WITH
AN BERMUDA HIGH PATTERN MAINTAINING ITSELF THROUGH WEDNESDAY. FOR
THE REGION THIS WILL MEAN A RETURN OF LOW LEVEL MOISTURE INTO THE
REGION AND DIURNAL SHOWERS AND STORMS DEVELOPING...ESPECIALLY OVER
THE MOUNTAINS. TEMPERATURES WILL ALSO TREND WARMER. DAYTIME HIGHS
IN THE UPPER 80S TO AROUND 90 WILL BE COMMON ACROSS THE PIEDMONT
WITH A MIX OF UPPER 70S TO MID 80S IN THE MOUNTAINS. OVERNIGHT
LOWS WILL BE IN THE LOW TO MID 60S.
THE UPPER RIDGE BEGINS TO BECOME DISPLACED WESTWARD IN RESPONSE A
DEEPENING TROUGH ACROSS THE GREAT LAKES REGION BY WEDNESDAY NIGHT.
THIS TROUGH IS PROGGED TO DEEPEN ACROSS THE EAST COAST BY THURSDAY
AND BRING AN ASSOCIATED COLD FRONT THROUGH THE REGION BY THURSDAY
EVENING. THE RESULT WILL BE A MORE ORGANIZED SERIES OF SHOWERS
AND STORMS DEVELOPING BOTH OVER THE AREA...AND ALSO MOVING INTO
THE REGION IN ASSOCIATION WITH THE FRONT. TEMPERATURES WILL ONLY
BE SLIGHTLY COOLER DURING THE DAY THURSDAY COMPARED TO THE
PREVIOUS TWO DAYS THANKS MAINLY TO MORE CLOUDS AND MORE
PRECIPITATION. LOWER DEW POINT AIR MOVES INTO THE AREA BEHIND THE
FRONT THURSDAY NIGHT...AND THUS ALLOW FOR COOLER LOW TEMPERATURES.
MID TO UPPER 50S ARE EXPECTED ACROSS THE MOUNTAINS WITH LOWER 60S
ACROSS THE PIEDMONT.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 1230 PM EDT SUNDAY...
UPPER RIDGE RETROGRADES BACK TO THE CENTRAL PLAINS BY FRIDAY WITH A
500 MB TROF DIGGING IN THE EASTERN UNITED STATES. ECMWF CLOSES OFF
AN UPPER LOW OVER NEW ENGLAND ON SATURDAY WHILE THE GFS IS FASTER
MOVING THE LONG WAVE TROF OFFSHORE. EITHER WAY...NET RESULT WILL
STILL BE NORTHWEST FLOW FOR THE FORECAST AREA.
BOTH THE ECMWF AND GFS ENSEMBLES HAVE SIMILAR TIMING WITH A SURFACE
COLD FRONT CROSSES THROUGH THE COUNTY WARNING AREA ON THURSDAY.
SOUTHWEST WINDS ON THURSDAY WILL KEEP TEMPERATURES ABOVE NORMAL AND
WILL BRING DEEP MOISTURE INTO THE AREA AHEAD OF THE FRONT. A LARGE
HIGH PRESSURE SYSTEM...ALONG WITH A COOLER AND DRIER AIRMASS BUILDS
IN BY SATURDAY. APPEARS THAT 850MB TEMPERATURES WILL LOWER IN THE +8
TO +10 RANGE BEHIND THE FRONT.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 134 PM EDT MONDAY...
SCT TO BKN MVFR CLOUDS WITH ISOLATED IFR ACROSS THE SOUTHERN BLUE
RIDGE MOUNTAINS THIS AFTERNOON INTO TONIGHT. HIGH PRESSURE WILL
SHIFT EAST AND OFF THE MID ATLANTIC COAST THIS AFTERNOON INTO
TONIGHT. THIS SHOULD ALLOW LOW LEVEL WINDS TO VEER AROUND TO THE
SOUTH/SW AND HELP SCOUR OUT ANY RESIDUAL LOW CLOUDS THAT MAY BE
STUCK OUT EAST. SCT-BKN 4-6KFT CU FIELD EXPECTED IN THE WEST THIS
AFTERNOON INTO TONIGHT. ISOLATED CELLS FORMING ON KFCX WSR-88D AT
17Z IN THE UNSTABLE AIR ACROSS WESTERN MOUNTAINS.
THIS ISOLATED CONVECTION THIS AFTERNOON WILL DIMINISH WITH THE
LOSS OF SOLAR HEATING THIS EVENING. ANY SHOWER OR THUNDERSTORM
LOOKS TOO ISOLATED TO MENTION IN THE TAF SITES. LOW LEVEL
MOISTURE AND LIGHT WINDS TONIGHT WILL RESULT IN AREAS OF FOG
OVERNIGHT. LWB HAS THE BEST CHANCE FOR FOG TONIGHT...WITH LIFR
EXPECTED OVERNIGHT INTO TUESDAY MORNING.
TUESDAY INTO MID WEEK...EXPECT A RETURN TO MORE TYPICAL SUMMERLIKE
WEATHER WITH INCREASING CHANCES FOR DIURNALLY-DRIVEN SHOWERS AND
THUNDERSTORMS. AT THIS POINT...NO WIDESPREAD EXTENDED DURATION OF
POOR AVIATION CONDITIONS ARE EXPECTED THROUGH MID WEEK...OUTSIDE OF
EARLY MORNING FOG AND PATCHY LOW STRATUS. ANOTHER COLD FRONT WILL
ARRIVE ON THURSDAY WITH PERHAPS A MORE SUBSTANTIAL BAND OF SHOWERS
AND STORMS THURSDAY AFTERNOON...WHICH MAY ALLOW FOR A PERIOD OF SUB-
VFR CONDITIONS INTO THURSDAY EVENING. MUCH DRIER AND COOLER AIR
LOOKS TO ARRIVE BEHIND THE FRONT MARKING FOR THE RETURN OF
WIDESPREAD VFR FOR THE END OF THE WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/KK
SHORT TERM...DS
LONG TERM...AMS
AVIATION...JH/KK
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1142 AM EDT MON SEP 9 2013
.SYNOPSIS...
A WEAK COOL FRONT WILL DRIFT SOUTH INTO THE CAROLINAS TODAY AND
GRADUALLY DISSIPATE THIS EVENING. HIGH PRESSURE BUILDING NORTH OF
THE AREA WILL WEDGE SOUTH ALONG THE APPALACHIANS THIS MORNING
BEFORE SLIDING QUICKLY EAST AND OFFSHORE THE MID ATLANTIC COAST
THIS AFTERNOON. HIGH PRESSURE ALOFT SLIDES EAST INTO THE AREA BY
TUESDAY BRINGING A RETURN TO MORE SUMMERLIKE WEATHER FOR MID WEEK
AHEAD OF A STRONG COLD FRONT THAT ARRIVES ON THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1140 AM EDT MONDAY... INCREASED CLOUD COVER FOR THIS
AFTERNOON AND LOWERED TEMPERATURES. CLOUDS AND LOW LEVEL COOL POOL
ARE BANKING UP AGAINST THE BLUE RIDGE RIDGE WITH CU FIELD
DEVELOPING ALONG SOUTHERN PORTIONS OF CWA WHERE THERE WAS SOME
MORNING SUNSHINE. SHAPED THE AFTERNOON POPS TOWARDS THE HRRR WITH
CONVECTION ACROSS HIGHER TERRAIN AND SPOTTY ACTIVITY IN THE EAST.
MORE ADJUSTMENTS THIS AFTERNOON...
AS OF 910 AM EDT MONDAY...
WITH THIS MORNING RNK 12Z/8AM SOUNDING SHOWING SHALLOW MOISTURE
UP TO 870 MB...EXPECT CLOUD COVER TO PERSIST FOR A COUPLE OF HOURS
THIS MORNING WITH THE WEAK FRONT AND LOW LEVEL WEDGE. WITH THIS
RICH CLOUD COVER...LOWERED TEMPERATURES FOR THIS MORNING INTO
THIS AFTERNOON. ISOLATED TO SCATTERED POPS SUPPORTED BY
ECMWF...GFS NAM...MAINLY ACROSS THE HIGHER TERRAIN. 06Z RNK WRF
ARW PLACED THE FOCUS OF CONVECTION ACROSS THE NORTHWEST
MOUNTAINS. WILL SHAPE POPS AND ISC GRIDS AS MORNING PROGESSES.
AS OF 230 AM EDT MONDAY...
FORECAST REMAINS RATHER UNCERTAIN OVER THE NEXT 24 HOURS WITH
A WEAK FRONT DROPPING TO THE SOUTH THIS MORNING AND A LOW LEVEL
WEDGE DEVELOPING BEHIND THE BOUNDARY ALONG THE MOUNTAINS INTO
THIS AFTERNOON. KEY IS WHETHER OR NOT ANY LOW CLOUDS DEVELOP
WITHIN THE LOW LEVEL COOL POOL THIS MORNING AND BANK UP ALONG THE
BLUE RIDGE LONGER THAN EXPECTED DESPITE HIGH PRES EXITING OFF TO
THE NE AFTER MIDDAY. MODELS CONTINUE TO SUGGEST THIS SCENARIO WITH
ONGOING ISOLATED -SHRA FADING OUT EAST BY DAYBREAK ONLY TO HAVE
LOW CLOUDS SPILL BACK WEST AIDED BY WEAK UPSLOPE. THEREFORE HAVE
TRENDED CLOUDIER EARLY ON EASTERN HALF WITH LESS CLOUDS WEST
WHERE EARLY FOG/STRATUS MORE PREVALENT.
LOW LEVEL FLOW WILL GRADUALLY VEER AROUND TO THE SOUTH/SW FROM
WEST TO EAST THIS AFTERNOON AS THE HIGH EXITS WITH INCREASING
WEAK MOISTURE CONVERGENCE FAR WEST. HOWEVER MAY STILL SEE A WEAK
RESIDUAL WEDGE HANG IN OUT EAST PER SUBTLE SE FLOW AND LINGERING
STABILITY OFF GUIDANCE. THIS SHOULD KEEP ANY ADDED SHRA CONFINED
TO THE MOUNTAINS WHERE MODELS DEPICT BEST AXIS OF THETA-E AND
DECENT CAPES AHEAD OF PERHAPS A WEAK MID LEVEL WAVE SPILLING IN
FROM THE NW LATE. THIS COULD BE ENOUGH TO SPARK MAINLY ISOLATED
SHRA/TSRA BUT IFFY GIVEN LACK OF MUCH LOW LEVEL FOCUS...BUILDING
5H HEIGHTS FROM THE WEST AND ONLY SHALLOW MOISTURE. THUS STAYING
WITH 20/30 POPS WEST WHICH MESHES BEST WITH THE LATEST ENSEMBLES
AND DRY EAST WHERE CLOUDS MAY LINGER. HIGH TEMPS TRICKY PENDING
TIMING OF MORE INSOLATION EAST AND WEAK VEERING FLOW FOLLOWING A
WARM START. IF CLOUDS LOCK IN ACROSS THE NE THEN MAY BE TOUGH TO
REACH 80...WHILE ELSW COULD ZOOM UP ESPCLY WEST GIVEN WEAK
DOWNSLOPING SO BUMPED UP HIGHS THERE AND TRIMMED BACK OUT EAST.
UPPER RIDGE OVER THE MIDWEST SHIFTS EAST OVERNIGHT AS THE SURFACE
HIGH EXITS FARTHER EAST WHILE ELONGATING BACK INLAND TO OVER THE
CAROLINAS LATE. THIS SHOULD ALLOW FOR A WEAK SUBSIDENCE REGIME TO
LINGER WITH ANY RESIDUAL EVENING SHRA FROM EARLIER OUTFLOW...AND
POSSIBLY ISOLATED SHRA ACROSS THE FAR NW WITH ANY FAINT IMPULSE
SPILLING SE OVERNIGHT. OTRW PC NORTH/WEST TO CLEAR ELSW WITH
THINGS A BIT MORE MUGGY GIVEN LOWS MAINLY IN THE 60S.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM EDT MONDAY...
UPPER RIDGE CONTINUES TO BUILD OVER THE REGION ON TUESDAY WITH
AN BERMUDA HIGH PATTERN MAINTAINING ITSELF THROUGH WEDNESDAY. FOR
THE REGION THIS WILL MEAN A RETURN OF LOW LEVEL MOISTURE INTO THE
REGION AND DIURNAL SHOWERS AND STORMS DEVELOPING...ESPECIALLY OVER
THE MOUNTAINS. TEMPERATURES WILL ALSO TREND WARMER. DAYTIME HIGHS
IN THE UPPER 80S TO AROUND 90 WILL BE COMMON ACROSS THE PIEDMONT
WITH A MIX OF UPPER 70S TO MID 80S IN THE MOUNTAINS. OVERNIGHT
LOWS WILL BE IN THE LOW TO MID 60S.
THE UPPER RIDGE BEGINS TO BECOME DISPLACED WESTWARD IN RESPONSE A
DEEPENING TROUGH ACROSS THE GREAT LAKES REGION BY WEDNESDAY NIGHT.
THIS TROUGH IS PROGGED TO DEEPEN ACROSS THE EAST COAST BY THURSDAY
AND BRING AN ASSOCIATED COLD FRONT THROUGH THE REGION BY THURSDAY
EVENING. THE RESULT WILL BE A MORE ORGANIZED SERIES OF SHOWERS
AND STORMS DEVELOPING BOTH OVER THE AREA...AND ALSO MOVING INTO
THE REGION IN ASSOCIATION WITH THE FRONT. TEMPERATURES WILL ONLY
BE SLIGHTLY COOLER DURING THE DAY THURSDAY COMPARED TO THE
PREVIOUS TWO DAYS THANKS MAINLY TO MORE CLOUDS AND MORE
PRECIPITATION. LOWER DEW POINT AIR MOVES INTO THE AREA BEHIND THE
FRONT THURSDAY NIGHT...AND THUS ALLOW FOR COOLER LOW TEMPERATURES.
MID TO UPPER 50S ARE EXPECTED ACROSS THE MOUNTAINS WITH LOWER 60S
ACROSS THE PIEDMONT.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 1230 PM EDT SUNDAY...
UPPER RIDGE RETROGRADES BACK TO THE CENTRAL PLAINS BY FRIDAY WITH A
500 MB TROF DIGGING IN THE EASTERN UNITED STATES. ECMWF CLOSES OFF
AN UPPER LOW OVER NEW ENGLAND ON SATURDAY WHILE THE GFS IS FASTER
MOVING THE LONG WAVE TROF OFFSHORE. EITHER WAY...NET RESULT WILL
STILL BE NORTHWEST FLOW FOR THE FORECAST AREA.
BOTH THE ECMWF AND GFS ENSEMBLES HAVE SIMILAR TIMING WITH A SURFACE
COLD FRONT CROSSES THROUGH THE COUNTY WARNING AREA ON THURSDAY.
SOUTHWEST WINDS ON THURSDAY WILL KEEP TEMPERATURES ABOVE NORMAL AND
WILL BRING DEEP MOISTURE INTO THE AREA AHEAD OF THE FRONT. A LARGE
HIGH PRESSURE SYSTEM...ALONG WITH A COOLER AND DRIER AIRMASS BUILDS
IN BY SATURDAY. APPEARS THAT 850MB TEMPERATURES WILL LOWER IN THE +8
TO +10 RANGE BEHIND THE FRONT.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
AS OF 640 AM EDT MONDAY...
MAIN CONCERNS CONTINUE WITH THE EXTENT OF LOW CIGS IN THE WAKE OF
THE FRONT ACROSS THE EAST AND DENSE VALLEY FOG OVER THE WEST THIS
MORNING. LATEST SATELLITE PICS AND OBS SHOW THAT THE LOWER
STRATO-CU ALONG WITH SOME STRATUS REMAINS JUST EAST OF ROUTE 29
ATTM. HOWEVER LOWER CIGS ARE GRADUALLY SHIFTING WEST TOWARD THE
BLUE RIDGE AIDED BY INCREASING LOW LEVEL NE FLOW BEHIND THE FRONT.
THIS MAY PUSH MVFR/IFR CIGS SOUTH AND WEST TO KROA/KDAN EARLY THIS
MORNING WITH LINGERING LOW IFR/MVFR AT KLYH LIKELY THROUGH MUCH OF
THE MORNING. STILL LOW CONFIDENCE IN JUST HOW FAR WEST THIS CANOPY
WILL GET BEFORE STARTING TO MIX OUT WITH HEATING BY MID/LATE
MORNING. SINCE APPEARS THE BLUE RIDGE MAY SERVE AS THE WESTERN
EXTENT OF THE MVFR CIGS...HAVE FASTER IMPROVEMENT FROM BCB WEST
WHERE MAINLY DEALING WITH IFR/LIFR IN FOG THAT SHOULD DISSIPATE A
COUPLE HOURS AFTER SUNRISE. POTENTIAL TO SEE LYH AND PERHAPS ROA
STAY SUB-VFR INTO EARLY AFTERNOON IF THE LOW DECK LOCKS IN BUT TOO
IFFY TO HOLD LOW CONDITIONS THAT LONG GIVEN WARMTH ALOFT. THUS
TRENDING EVEN THOSE LOCATIONS VFR BY MIDDAY IF NOT SOONER AT ROA.
OTRW THE FRONT WASHES OUT TO THE SOUTH LATER TODAY WITH HIGH
PRESSURE QUICKLY SHIFTING EAST AND OFF THE MID ATLANTIC COAST BY
AFTERNOON. THIS SHOULD ALLOW LOW LEVEL WINDS TO VEER AROUND TO
THE SOUTH/SW AND HELP SCOUR OUT ANY RESIDUAL LOW CLOUDS THAT MAY
BE STUCK OUT EAST IN THE AFTERNOON. THIS SHOULD LEAD TO A SCTD-
BKN 4-6KFT CU FIELD WITH MOST OF THE BKN LAYER CU DEVELOPING OVER
THE WEST ESPCLY LWB- BLF. ANY SHRA ALSO LOOKS TOO ISOLATED TO
MENTION SO KEEPING OUT OF THE TAF SITES FOR NOW.
AFTER TODAY...EXPECT A RETURN TO MORE TYPICAL SUMMERLIKE WEATHER
WITH INCREASING CHANCES FOR DIURNALLY-DRIVEN SHOWERS AND
THUNDERSTORMS. AT THIS POINT...NO WIDESPREAD EXTENDED DURATION OF
POOR AVIATION CONDITIONS ARE EXPECTED THROUGH MID WEEK...OUTSIDE
OF EARLY MORNING FOG AND PATCHY LOW STRATUS. ANOTHER COLD FRONT
WILL ARRIVE ON THURSDAY WITH PERHAPS A MORE SUBSTANTIAL BAND OF
SHOWERS AND STORMS THURSDAY AFTERNOON...WHICH MAY ALLOW FOR A
PERIOD OF SUB-VFR CONDITIONS INTO THURSDAY EVENING. MUCH DRIER AND
COOLER AIR LOOKS TO ARRIVE BEHIND THE FRONT MARKING FOR THE RETURN
OF WIDESPREAD VFR FOR THE END OF THE WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/KK
SHORT TERM...DS
LONG TERM...AMS
AVIATION...JH/PM
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
847 PM CDT TUE SEP 10 2013
.UPDATE...
BASED ON SURFACE OBS AND REGIONAL RADARS...THE ADVANCING COLD
FRONT IS LOCATED FROM NORTH OF SHEBOYGAN TO FOND DU LAC TO MINERAL
POINT AND IS CONTINUING ITS SLOW MOVEMENT SOUTHEAST. THE AIRMASS
AHEAD OF IT MIXED OUT PRETTY HARD THIS AFTERNOON AND IS STRUGGLING
TO RECOVER. DEWPOINTS ARE STILL IN THE 50S AT A FEW SPOTS IN
SCENTRAL WI. MOISTURE IS LIMITED ALOFT AS WELL. AS A WEAK MID
LEVEL TROF ROLLS BY TO THE NORTH...WE ARE SEEING SOME DECENT F-GEN
FORCING ALONG AND NORTH OF THE COLD FRONT. THE ELEVATED
INSTABILITY IS WEAK THOUGH...NOT GETTING MUCH ABOVE 600J/KG. MID
LEVEL LAPSE RATES ARE RATHER LOW. THE ACTIVITY THUS FAR HAS
STRUGGLED TO MAINTAIN DEVELOPMENT. JUST TOO MUCH ENTRAINMENT OF
DRY AIR GOING ON. THE MODELS ARE PERSISTENT ON EXPANDING A POST
FRONTAL LINE OF CONVECTION TONIGHT. THE HRRR IS MUCH LESS
SUPPORTIVE OF THIS SCENARIO...BUT DOES TRY TO INCREASE THE PRECIP
A BIT TOWARD 12Z WED. THIS IS ABOUT THE TIME OF THE ARRIVAL OF THE
MID LEVEL TROF AXIS. GIVEN THE UNCERTAINTY...WILL HOLD OFF ON
BUMPING POPS ANY HIGHER THAN WHAT WE HAVE RIGHT NOW. THAT MAY EVEN
BE TOO HIGH.
THE HIGHER DEWPOINTS DON/T REALLY SCOUR OUT TOMORROW UNTIL LATER
IN THE DAY WHEN THE NORTHEAST WINDS KICK IN. SO...WE STILL HAVE A
CHANCE FOR SOME MUCH NEEDED RAIN INTO TOMORROW. THE MODELS
CONTINUE TO SLOW THIS SYSTEM DOWN A NOTCH WITH EACH RUN.
&&
.AVIATION/06Z TAFS/...
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. THE CHANCE FOR
SHOWERS AND THUNDERSTORMS IS RATHER LIMITED AND GIVEN THE LOWER
PROBABILITIES...THEY HAVE THEREFORE BEEN LEFT OUT OF THE OFFICIAL
TAF FORECAST. EXPECT CIGS OF ABOUT 4-6KFT THROUGH MUCH OF
WEDNESDAY...CLEARING FROM NORTH TO SOUTH WEDNESDAY AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 337 PM CDT TUE SEP 10 2013/
SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM
BROAD 500 MILLIBAR TROUGH SHIFTING EAST FROM THE NORTHERN PLAINS.
WATER VAPOR SHOWS MOISTURE PLUME AND JET MAX FROM SOUTH DAKOTA TO
LAKE SUPERIOR. ANOTHER MOISTURE PLUME LIFTING NNE FROM IOWA. 12Z
4.5KM SPC WRF APPEARS TOO QUICK ON DEVELOPMENT THIS AFTERNOON
ACROSS SW WI. LEANING MORE TOWARDS HRRR SOLUTION WITH DEVELOPMENT
NORTH OF THE CWA AND THEN JUST OOZING INTO CWA LATER THIS EVENING
AND OVERNIGHT. FRONT WILL NOT HAVE MUCH OOMPH INTO SRN WI AS THE
NIGHT GOES ON SO INSTABILITY EVEN LESS THAN THE AFTN 500-1000
J/KG...SO CONFIDENCE NOT GREAT THAT ANYTHING REORGANIZED WILL
SURVIVE TOO DEEP INTO SRN WI.
WEDNESDAY...FORECAST CONFIDENCE MEDIUM
WEAK 850 MILLIBAR CONVERGENCE ALONG WITH 500 MILLIBAR CYCLONIC
FLOW WILL RESULT IN SMALL POPS ACROSS MAINLY THE SOUTHERN CWA. 12Z
NAM IS DRY WHILE OTHER MODELS SHOWING LIGHT QPF. BULK OF ACTIVITY
LOOKS LIKE IT WILL BE FURTHER SOUTH OF THE STATE WITH BETTER
INSTABILITY. 925 TEMPS AVERAGED AMONGST THE MODELS SHOWS 21-23C
WHICH YIELDS QUITE A BIT OF HIGHS IN THE MID 80S.
WEDNESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM TO HIGH
THE INITIAL...WEAK COLD FRONT WILL SLIDE SWD INTO NRN IL AND NRN
IN BY WED EVENING WITH ANY TSTORM DEVELOPMENT EXPECTED THERE. THE
SECONDARY AND STRONGER COLD FRONT WILL THEN ARRIVE FROM THE NORTH
LATE WED NT. A SHARP CANADIAN UPPER TROUGH WILL ACCOMPANY THE
FRONT AND MOVE INTO THE NRN GRTLKS AND WI BY 12Z THU AND WILL MOVE
EAST OF WI BY FRI. LOW LEVEL INSTABILITY VIA COLD AIR ALOFT MAY
LEAD TO SCT SHOWERS OVER THE ERN CWA THU INTO THU EVENING. A NNELY
1000-850 MB FLOW AND LAKE TO 850 MB TEMP DIFFERENCES OF 13C OR
GREATER MAY CONTRIBUTE TO THE SHOWER POTENTIAL OVER THE LAKE
COUNTIES AS WELL. THE COLD AND DRY AIR ADVECTION TO SLOW DOWN BY
THU NT WITH MORE SUN THEN EXPECTED FOR FRI AS THE CANADIAN HIGH
CENTERS OVER WI. EXPECTED 925 MB TEMPS OF THE MID TO UPPER TEENS
CELSIUS FOR THU AND AROUND 10C FOR FRI...WILL YIELD HIGHS IN THE
MID 70S FOR THU AND LOWER TO MID 60S FOR FRI.
LONG TERM...
SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE MEDIUM
THE MAIN POLAR JET STREAM WILL REMAIN IN CANADA WITH ANOTHER
STRONG UPPER TROUGH AND LOW PRESSURE AREA MOVING ACROSS CANADA. SWLY
WINDS AND WARMER TEMPS WILL RETURN FOR SAT AND SUN OVER SRN WI
AHEAD OF THE TRAILING CANADIAN COLD FRONT THAT WILL PASS ON
SUNDAY. ONLY SMALL CHANCES FOR PCPN WITH THE FRONT. CANADIAN HIGH
PRESSURE WILL THEN TRACK FROM THE NRN GRTLKS SUN NT TO THE ERN
GRTLKS FOR MON AND POSSIBLY TUE. A DRY ELY FLOW WILL PREVAIL OVER
THE AREA WITH PLEASANT AND NEAR TO SLIGHTLY BELOW NORMAL TEMPS.
AVIATION/00Z TAFS/...VFR SKC INTO THE EVENING HOURS FOR TAF SITES.
EXPECT MID CLOUDS TO INCREASE TONIGHT AS FRONTAL BOUNDARY SAGS SOUTH
AND INFLUENCE OF UPPER JET ENHANCES VERTICAL MOTION. LATEST HRRR
KEEPS CONVECTION NORTH OF TAF SITES THROUGH 05Z. WILL BRING SOME
SHRA/TSRA INTO THE AREA LATER IN THE NIGHT. THE NAM IS THE ONLY
MODEL NOT SHOWING PRECIP WEDNESDAY. WARY THAT SOME SHRA WILL
LINGER THOUGH FORCING NEAR NIL ONCE LOW LEVEL BOUNDARY SAGS SOUTH.
MARINE...A FEW SOUTHWEST WIND GUSTS EXCEEDING CRITERIA SO WILL
LEAVE SMALL CRAFT GOING UNTIL 7 PM.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DAVIS
TONIGHT/WEDNESDAY AND AVIATION/MARINE...COLLAR
WEDNESDAY NIGHT THROUGH TUESDAY...GEHRING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
639 PM CDT TUE SEP 10 2013
.UPDATE...
ISSUED AT 639 PM CDT TUE SEP 10 2013
LOW TO MID LEVEL FRONTOGENESIS BEGINNING TO GET GOING FROM CENTRAL
IOWA INTO CENTRAL WISCONSIN...NOTED BY ISOLATED SHOWERS THAT HAVE
DEVELOPED. SO FAR ALL LIGHTNING ACTIVITY HAS STAYED DOWN TOWARDS
CENTRAL IOWA. HOWEVER...RAP/NAM/ECMWF SOUNDINGS ALL SHOW ELEVATED
INSTABILITY ON THE ORDER OF 250-750 J/KG LIFTED FROM 850MB. AS THE
FRONTOGENESIS STRENGTHENS PER MODEL PROGS THIS EVENING...
ANTICIPATING THAT SOME OF THE SHOWER ACTIVITY WILL TAKE ADVANTAGE
OF THIS INSTABILITY AND PRODUCE LIGHTNING. HRRR MODEL FORECASTS
SUGGEST THIS AS WELL. THEREFORE...HAVE ADDED ISOLATED- SCATTERED
THUNDERSTORMS BACK INTO THE FORECAST...MAINLY SOUTH OF INTERSTATE
90 WHERE THE ELEVATED INSTABILITY IS PROGGED. ADDITIONALLY...IT IS
POSSIBLE PRECIPITATION CHANCES WILL NEED TO BE RAISED ACROSS
PORTIONS OF THIS AREA WITH ADDED THUNDER. ECMWF/NAM/HRRR FORECASTS
THIS EVENING REALLY INCREASE PRECIPITATION COVERAGE. WILL MONITOR
TRENDS IN RADAR DATA TO SEE IF THE MODELS ARE HANDLING
PRECIPITATION OKAY. SO FAR THEY SEEM TO BE.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 244 PM CDT TUE SEP 10 2013
SURFACE MAP HAS LOW PRESSURE OVER LAKE SUPERIOR WITH A COLD FRONT
EXTENDING THROUGH CENTRAL UPPER MI TO JUST NORTH OF LA CROSSE...AND
THEN THROUGH NORTHERN IA. RADAR MOSAIC WAS SHOWING A SCATTERED BAND
OF POST-FRONTAL SHOWERS ACROSS WESTERN UPPER MI THROUGH NORTH
CENTRAL WI INTO SOUTHERN MN. NOT MUCH OF THIS REFLECTIVITY WAS BEING
REALIZED AT THE SURFACE...AND WHERE IT WAS...RAINFALL WAS SCANT WITH
GENERALLY .02 INCH OR LESS. PER THE RAP MODEL...THIS BAND OF SHOWERS
WAS TIED TO SOME 850-700MB FRONTOGENESIS BEHIND THE SURFACE FRONT.
OTHERWISE...TEMPERATURES ACROSS THE AREA RANGED FROM NEAR 80 ACROSS
NORTH CENTRAL WI...TO A FEW LOWER 90S ACROSS NORTHEAST IA INTO
SOUTHWEST WI.
SO...MAIN FORECAST CHALLENGE WILL BE RAIN CHANCES TONIGHT INTO
WEDNESDAY WITH THE PASSAGE OF THIS FRONT AND POST-FRONTAL FORCING.
LOOK FOR THE THE MAIN SURFACE FRONT TO CONTINUE PUSHING SOUTHEAST
THROUGH THE AREA TONIGHT WHILE 850-700MB FRONTOGENESIS LAGS BEHIND.
RAP SHOWING 850-700MB FG-FORCING...ALBEIT NOT OVERLY
STRONG...MAINTAINING ITSELF AS IT DRIFTS SOUTHEAST ACROSS THE AREA
THIS EVENING/OVERNIGHT. THE NAM ACTUALLY SHOWS THIS FORCING
INTENSIFYING A BIT...BUT MORE ACROSS EAST CENTRAL WI. BASED ON WHAT
IS HAPPENING NOW AND FORECAST FORCING SIGNAL...HAVE DOWNPLAYED
RAIN CHANCES AND DROPPED THUNDER MENTION AS FORCING AND CAPE WANE.
PLAN ON OVERNIGHT LOW TEMPERATURES IN THE UPPER 50S TO THE MIDDLE
60S.
FOR WEDNESDAY...WILL BE WATCHING THE COLD FRONTAL BOUNDARY CONTINUE
TO SLIP SOUTH OF OUR AREA WITH 850-700MB FG-FORCING ALMOST
NON-EXISTENT. AS SUCH...PUSHED ANY REMAINING SHOWER CHANCES SOUTH OF
THE FORECAST AREA BY AFTERNOON. OTHERWISE...LOOKING AT A MID-LEVEL
TROUGH/REINFORCING SHOT OF COOLER AIR DROPPING INT NORTHERN WI BY
LATE IN THE AFTERNOON. MODELS ARE PRODUCING SOME SHRA/ISOLATED
THUNDER WITH THIS WAVE...BUT KEEPING IT NORTH OF THE FORECAST AREA.
OTHERWISE...LOOK FOR HIGHS ACROSS THE FORECAST AREA IN THE 80-85
DEGREE RANGE.
COOLER/DRIER AIR FILTERS IN FOR WEDNESDAY NIGHT AS HIGH PRESSURE
BUILDS INTO THE UPPER MISSISSIPPI RIVER REGION FROM THE CENTRAL
CANADIAN PROVINCES. LOOK FOR OVERNIGHT LOWS IN THE 50-60 DEGREE
RANGE WITH NORTHWEST WINDS OF 5-10 MPH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 244 PM CDT TUE SEP 10 2013
CONTINUED DRY/COOL FLOW CONTINUES INTO THE AREA ON THURSDAY AS HIGH
PRESSURE BUILDS IN ACROSS THE NORTHERN PLAINS/MN. FAIRLY STEEP LAPSE
RATES WILL BE IN PLACE WITH 925MB TEMPERATURES IN THE 10-17C RANGE
AND 500MB IN THE -5 TO -15C RANGE. THIS IS EXPECTED TO PRODUCE A
PRETTY GOOD FIELD OF CUMULUS/STRATOCUMULUS...ESPECIALLY AREAS
NORTHEAST OF I-94. ANY SHOWER THREAT LOOKS TO STAY NORTH OF THE
AREA.
HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER PICTURE THURSDAY
NIGHT THROUGH SATURDAY. THURSDAY NIGHT AND ESPECIALLY FRIDAY NIGHT
WILL SET UP FAVORABLE RIVER VALLEY FOG CONDITIONS WITH CLEAR SKIES
AND LIGHT/CALM WINDS. RATHER CHILLY OVERNIGHT LOWS ARE ALSO EXPECTED
THURSDAY NIGHT AND FRIDAY NIGHT WITH PLANNED FORECAST LOWS
DROPPING INTO UPPER 30S IN THE FAVORED COLD SPOTS ALONG AND
NORTHEAST OF I-94. WILL HAVE TO WATCH CLOSELY FOR THE POTENTIAL OF
PATCHY FROST ACROSS THIS AREA THURSDAY NIGHT AS THE COLDEST CORE OF
AIR ALOFT SINKS ACROSS THE REGION.
WILL BE WATCHING THE HIGH DRIFT EAST OF THE AREA SATURDAY NIGHT
INTO SUNDAY AS A FAIRLY VIGOROUS //AT LEAST ACCORDING TO THE
ECMWF// MID-LEVEL TROUGH AND SURFACE COLD FRONT DROPS SOUTHEAST
INTO THE AREA. THE GFS IS NOT AS ENTHUSED AS THE ECMWF. NEW 12Z
ECMWF LOOKING MORE LIKE THE GFS NOW....KEEPING POPS SPLIT TO THE
NORTH AND SOUTH OF THE AREA. LOWERED POPS FOR NOW...BUT IF TREND
CONTINUES...COULD PROBABLY DROP POPS ALTOGETHER FOR THE AREA. WILL
KEEP AN EYE ON THIS.
A STRONG AREA OF CANADIAN HIGH PRESSURE BUILDS INTO THE AREA FOR
SUNDAY NIGHT AND HOLDS AT LEAST THROUGH MONDAY NIGHT. THIS IS
EXPECTED TO YIELD DRY CONDITIONS WITH SLIGHTLY BELOW NORMAL
TEMPERATURES THROUGH THE PERIOD. LOOK FOR OVERNIGHT LOWS IN THE
UPPER 40S TO THE LOWER 50S WITH HIGHS IN THE MIDDLE 60S TO AROUND
THE 70 DEGREE MARK.
THE ECMWF AND GFS THEN DIFFER A BIT WITH SPEED OF A SHORTWAVE TROUGH
PUSHING EAST OUT OF THE PLAINS ON TUESDAY. THE ECMWF IS THE FASTER
OF THE TWO...SPREADING SHOWER/THUNDERSTORM CHANCES IN DURING THE
DAY. THE GFS IS MUCH SLOW AND MAINTAINS RIDGING ACROSS THE AREA.
WILL KEEP A DRY/COOL FORECAST GOING FOR NOW AND WAIT FOR BETTER
MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 605 PM CDT TUE SEP 10 2013
A COLD FRONT MOVED THROUGH THE TAF SITES THIS AFTERNOON. IN ITS
WAKE...DRIER LOW LEVEL AIR ALONG WITH ALTOSTRATUS HAVE COME INTO
THE TAF SITES. SOME VERY LIGHT SHOWER ACTIVITY IS ALSO
ACCOMPANYING THE ALTOSTRATUS. EXPECTATIONS ARE FOR THE ALTOSTRATUS
AND SCATTERED VERY LIGHT SHOWER ACTIVITY...ALONG WITH THE COLD
FRONT...TO CONTINUE SINKING SLOWLY SOUTH THROUGH THE NIGHT
TONIGHT. SHOWER ACTIVITY SHOULD BE OUT OF THE TAF SITES BY
06-08Z...FOLLOWED BY THE ALTOSTRATUS BY 12-14Z. CLEAR SKIES WITH A
10 KT WEST TO NORTHWEST BREEZE LOOKS TO SET UP FOR WEDNESDAY
AFTERNOON AS HIGH PRESSURE BUILDS SOUTH TOWARDS THE DAKOTAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
605 PM CDT TUE SEP 10 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 244 PM CDT TUE SEP 10 2013
SURFACE MAP HAS LOW PRESSURE OVER LAKE SUPERIOR WITH A COLD FRONT
EXTENDING THROUGH CENTRAL UPPER MI TO JUST NORTH OF LA CROSSE...AND
THEN THROUGH NORTHERN IA. RADAR MOSAIC WAS SHOWING A SCATTERED BAND
OF POST-FRONTAL SHOWERS ACROSS WESTERN UPPER MI THROUGH NORTH
CENTRAL WI INTO SOUTHERN MN. NOT MUCH OF THIS REFLECTIVITY WAS BEING
REALIZED AT THE SURFACE...AND WHERE IT WAS...RAINFALL WAS SCANT WITH
GENERALLY .02 INCH OR LESS. PER THE RAP MODEL...THIS BAND OF SHOWERS
WAS TIED TO SOME 850-700MB FRONTOGENESIS BEHIND THE SURFACE FRONT.
OTHERWISE...TEMPERATURES ACROSS THE AREA RANGED FROM NEAR 80 ACROSS
NORTH CENTRAL WI...TO A FEW LOWER 90S ACROSS NORTHEAST IA INTO
SOUTHWEST WI.
SO...MAIN FORECAST CHALLENGE WILL BE RAIN CHANCES TONIGHT INTO
WEDNESDAY WITH THE PASSAGE OF THIS FRONT AND POST-FRONTAL FORCING.
LOOK FOR THE THE MAIN SURFACE FRONT TO CONTINUE PUSHING SOUTHEAST
THROUGH THE AREA TONIGHT WHILE 850-700MB FRONTOGENESIS LAGS BEHIND.
RAP SHOWING 850-700MB FG-FORCING...ALBEIT NOT OVERLY
STRONG...MAINTAINING ITSELF AS IT DRIFTS SOUTHEAST ACROSS THE AREA
THIS EVENING/OVERNIGHT. THE NAM ACTUALLY SHOWS THIS FORCING
INTENSIFYING A BIT...BUT MORE ACROSS EAST CENTRAL WI. BASED ON WHAT
IS HAPPENING NOW AND FORECAST FORCING SIGNAL...HAVE DOWNPLAYED
RAIN CHANCES AND DROPPED THUNDER MENTION AS FORCING AND CAPE WANE.
PLAN ON OVERNIGHT LOW TEMPERATURES IN THE UPPER 50S TO THE MIDDLE
60S.
FOR WEDNESDAY...WILL BE WATCHING THE COLD FRONTAL BOUNDARY CONTINUE
TO SLIP SOUTH OF OUR AREA WITH 850-700MB FG-FORCING ALMOST
NON-EXISTENT. AS SUCH...PUSHED ANY REMAINING SHOWER CHANCES SOUTH OF
THE FORECAST AREA BY AFTERNOON. OTHERWISE...LOOKING AT A MID-LEVEL
TROUGH/REINFORCING SHOT OF COOLER AIR DROPPING INT NORTHERN WI BY
LATE IN THE AFTERNOON. MODELS ARE PRODUCING SOME SHRA/ISOLATED
THUNDER WITH THIS WAVE...BUT KEEPING IT NORTH OF THE FORECAST AREA.
OTHERWISE...LOOK FOR HIGHS ACROSS THE FORECAST AREA IN THE 80-85
DEGREE RANGE.
COOLER/DRIER AIR FILTERS IN FOR WEDNESDAY NIGHT AS HIGH PRESSURE
BUILDS INTO THE UPPER MISSISSIPPI RIVER REGION FROM THE CENTRAL
CANADIAN PROVINCES. LOOK FOR OVERNIGHT LOWS IN THE 50-60 DEGREE
RANGE WITH NORTHWEST WINDS OF 5-10 MPH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 244 PM CDT TUE SEP 10 2013
CONTINUED DRY/COOL FLOW CONTINUES INTO THE AREA ON THURSDAY AS HIGH
PRESSURE BUILDS IN ACROSS THE NORTHERN PLAINS/MN. FAIRLY STEEP LAPSE
RATES WILL BE IN PLACE WITH 925MB TEMPERATURES IN THE 10-17C RANGE
AND 500MB IN THE -5 TO -15C RANGE. THIS IS EXPECTED TO PRODUCE A
PRETTY GOOD FIELD OF CUMULUS/STRATOCUMULUS...ESPECIALLY AREAS
NORTHEAST OF I-94. ANY SHOWER THREAT LOOKS TO STAY NORTH OF THE
AREA.
HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER PICTURE THURSDAY
NIGHT THROUGH SATURDAY. THURSDAY NIGHT AND ESPECIALLY FRIDAY NIGHT
WILL SET UP FAVORABLE RIVER VALLEY FOG CONDITIONS WITH CLEAR SKIES
AND LIGHT/CALM WINDS. RATHER CHILLY OVERNIGHT LOWS ARE ALSO EXPECTED
THURSDAY NIGHT AND FRIDAY NIGHT WITH PLANNED FORECAST LOWS
DROPPING INTO UPPER 30S IN THE FAVORED COLD SPOTS ALONG AND
NORTHEAST OF I-94. WILL HAVE TO WATCH CLOSELY FOR THE POTENTIAL OF
PATCHY FROST ACROSS THIS AREA THURSDAY NIGHT AS THE COLDEST CORE OF
AIR ALOFT SINKS ACROSS THE REGION.
WILL BE WATCHING THE HIGH DRIFT EAST OF THE AREA SATURDAY NIGHT
INTO SUNDAY AS A FAIRLY VIGOROUS //AT LEAST ACCORDING TO THE
ECMWF// MID-LEVEL TROUGH AND SURFACE COLD FRONT DROPS SOUTHEAST
INTO THE AREA. THE GFS IS NOT AS ENTHUSED AS THE ECMWF. NEW 12Z
ECMWF LOOKING MORE LIKE THE GFS NOW....KEEPING POPS SPLIT TO THE
NORTH AND SOUTH OF THE AREA. LOWERED POPS FOR NOW...BUT IF TREND
CONTINUES...COULD PROBABLY DROP POPS ALTOGETHER FOR THE AREA. WILL
KEEP AN EYE ON THIS.
A STRONG AREA OF CANADIAN HIGH PRESSURE BUILDS INTO THE AREA FOR
SUNDAY NIGHT AND HOLDS AT LEAST THROUGH MONDAY NIGHT. THIS IS
EXPECTED TO YIELD DRY CONDITIONS WITH SLIGHTLY BELOW NORMAL
TEMPERATURES THROUGH THE PERIOD. LOOK FOR OVERNIGHT LOWS IN THE
UPPER 40S TO THE LOWER 50S WITH HIGHS IN THE MIDDLE 60S TO AROUND
THE 70 DEGREE MARK.
THE ECMWF AND GFS THEN DIFFER A BIT WITH SPEED OF A SHORTWAVE TROUGH
PUSHING EAST OUT OF THE PLAINS ON TUESDAY. THE ECMWF IS THE FASTER
OF THE TWO...SPREADING SHOWER/THUNDERSTORM CHANCES IN DURING THE
DAY. THE GFS IS MUCH SLOW AND MAINTAINS RIDGING ACROSS THE AREA.
WILL KEEP A DRY/COOL FORECAST GOING FOR NOW AND WAIT FOR BETTER
MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 605 PM CDT TUE SEP 10 2013
A COLD FRONT MOVED THROUGH THE TAF SITES THIS AFTERNOON. IN ITS
WAKE...DRIER LOW LEVEL AIR ALONG WITH ALTOSTRATUS HAVE COME INTO
THE TAF SITES. SOME VERY LIGHT SHOWER ACTIVITY IS ALSO
ACCOMPANYING THE ALTOSTRATUS. EXPECTATIONS ARE FOR THE ALTOSTRATUS
AND SCATTERED VERY LIGHT SHOWER ACTIVITY...ALONG WITH THE COLD
FRONT...TO CONTINUE SINKING SLOWLY SOUTH THROUGH THE NIGHT
TONIGHT. SHOWER ACTIVITY SHOULD BE OUT OF THE TAF SITES BY
06-08Z...FOLLOWED BY THE ALTOSTRATUS BY 12-14Z. CLEAR SKIES WITH A
10 KT WEST TO NORTHWEST BREEZE LOOKS TO SET UP FOR WEDNESDAY
AFTERNOON AS HIGH PRESSURE BUILDS SOUTH TOWARDS THE DAKOTAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...AJ
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 403 PM CDT MON SEP 9 2013
PLENTY OF QUESTIONS REMAIN REGARDING THE CHANCE FOR CONVECTION
TODAY. THERE WERE EVEN A FEW SHOWERS THAT WERE ON THEIR WAY OUT
OF THE AREA AT 20Z THAT APPEAR TO HAVE DEVELOPED ALONG A BOUNDARY
FROM THE THUNDERSTORM COMPLEX THAT MOVED ACROSS MINNESOTA
OVERNIGHT. THERE IS PLENTY OF INSTABILITY...MESOANALYSIS HAD
MUCAPES MAINLY IN THE 1000-3000J/KG RANGE EXCEPT NEAR THE UPPER
MICHIGAN BORDER WHERE THEY WERE IN THE 500-1000J/KG RANGE AT 20Z.
WEAKEST CIN WAS FROM NORTH CENTRAL AND NORTHEAST WISCONSIN
SOUTHWEST INTO EASTERN IOWA...BUT STRONG WARM ADVECTION ALOFT
CONTINUED TO HAMPER CONVECTIVE DEVELOPMENT ACROSS THE AREA.
LIGHT EAST OR SOUTH WINDS THIS MORNING HAVE BECOME SOUTHERLY AND
INCREASED DURING THE DAY. A WARM FRONT WAS MOVING NORTHEAST INTO
CENTRAL WISCONSIN THIS AFTERNOON AND WAS FORECAST TO MAKE IT TO
NEAR THE WISCONSIN/UPPER MICHIGAN BORDER BY 00Z. THIS MAY BE A
BIT TOO QUICK BASED ON ITS SPEED DURING THE DAY. THE WESTERLY FLOW
OF WARM AIR ALOFT WAS HELPING TO PRODUCE STRONG LOW-LEVEL AND
DEEP-LAYER SHEAR...ESPECIALLY ACROSS NORTHERN WISCONSIN AND UPPER
MICHIGAN.
STORMS MAY FIRE AS THE SURFACE LOW IN EASTERN MINNESOTA MOVES
ACROSS NORTHERN WISCONSIN LATER TONIGHT. EXPERIMENTAL COMPOSITE
REFLECTIVITY FROM THE 18Z HRRR DID NOT REALLY SHOW ANYTHING ACROSS
THE AREA...THOUGH IT DID SUGGEST CONVECTIVE ACTIVITY IN
CENTRAL/SOUTHERN WISCONSIN TODAY THAT DID NOT DEVELOP. IF STORMS
DO DEVELOP...THEY COULD PRODUCE LARGE HAIL AND DAMAGING WINDS. AN
ISOLATED TORNADO WAS EVEN MENTIONED BY SPC IN THEIR DAY ONE
OUTLOOK...WITH STORMS DEVELOPING INTO A FORWARD PROPAGATING MCS
WITH LLJ DEVELOPMENT...RESULTING IN MAINLY A DAMAGING WIND EVENT
THEREAFTER.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 403 PM CDT MON SEP 9 2013
LITTLE CHANGE IN SCENARIO FROM PAST FEW DAYS WITH AREA
TRANSITIONING INTO A NORTHWEST FLOW REGIME BY WED. MODELS IN
SIMILAR AGREEMENT THROUGH THE END OF THE WORK WEEK...THEN BEGIN
TO DIFFER AS MORE ZONAL PATTERN BUILDS IN. PRECIPITATION CHANCES
FIRST PART OF FORECAST MAIN CONCERNS.
WEAK COLD FRONT WILL SLOWLY SAG SOUTH THROUGH CWA ON TUE...THEN
SOUTH OF THE REGION TUESDAY NIGHT. MODELS TRENDING DRY THROUGH AM
WITH LIMITED CONVERGENCE ALONG FRONT AND NO UPPER SUPPORT. MODELS
A BIT MORE BULLISH ON QPF CHANCES LATE TUE AFTN AND OVERNIGHT...AS
WEAK WAVE MOVES NORTHEAST ALONG FRONT IN RESPONSE TO SHORT WAVE
TROF AND SOME JET ENERGY MOVING THROUGH. BUMPED POPS UP TO LIKELY
IN THE FAR SOUTH. PW`S STILL IN THE 1.5 TO 2 INCH RANGE WITH HEAVY
RAIN BIGGEST THREAT.
POSSIBILITY OF SHOWERS CONTINUES INTO THU AS UPPER DISTURBANCES
DROP SOUTHEAST THROUGH THE WESTERN LAKES. LINGERING LOW LEVEL
MOISTURE TO LEAD TO BETTER INSTABILITY AND CHANCE OF PCPN ON WED BUT
LATEST RUNS SHOW RATHER STRONG SYSTEM DROPPING THROUGH ON THU.
HAVE STAYED DRY THU ATTM GIVEN MOISTURE AND TIMING CONCERNS.
HIGH PRESSURE BUILDS IN LATER THU FOR DRY CONDITIONS THROUGH SAT.
HIGH TO SHIFT EAST OF AREA SAT NIGHT ALLOWING RETURN FLOW TO
DEVELOP. THIS WILL BRING A GOOD CHANCE OF SHOWERS AND ISOLD TSTMS
TO THE REGION SAT NIGHT INTO SUN.
COLDER AIR MOVES IN BEHIND STRONG COLD FRONT ON WED WITH
TEMPERATURES FALLING BACK TO NORMAL OR BELOW FOR REMAINDER OF
PERIOD. COOLEST TEMPERATURES EXPECTED FRI WITH COOL NORTHEAST
FLOW.
MAINTAINED SMALL CHANCE FOR LAKE EFFECT SHOWERS ON THU...THOUGH
WINDS MARGINAL. WILL LIKELY SEE LAKE CLOUDS AT TIMES OVER THE
NORTH THOUGH CAUSING HAVOC WITH LOW TEMP FORECASTS.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 111 PM CDT MON SEP 9 2013
IFR CIGS AND VSBYS ACROSS MUCH OF THE FORECAST AREA
WERE THE FIRST AREA OF CONCERN. VISIBLE SATELLITE IMAGERY SHOWED
STRATUS AND FOG ACROSS SOUTHERN AND CENTRAL WISCONSIN RAPIDLY
ERODING FROM THE SOUTH DURING THE LATE MORNING HOURS AS A WARM
FRONT PUSHED NORTHWARD. THE FRONT WILL CONTINUE TO MAKE PROGRESS
TO THE NORTH BUT NORTHERN WISCONSIN SHOULD BE SLOWER TO CLEAR
DUE TO REMNANTS OF OVERNIGHT/MORNING CONVECTION AND SOME MID/HIGH
CLOUDS OVER THAT PART OF THE STATE. WOULD EXPECT VFR CONDITIONS TO
PREVAIL ACROSS THE VAST MAJORITY OF THE AREA BY LATE AFTERNOON.
SURFACE WINDS WILL SHIFT TO THE SOUTH AND INCREASE...THEN BECOME
SOUTHWEST AS WINDS ALOFT VEER AND INCREASE CONSIDERABLY. HAVE LEFT
THE MENTION OF LLWS IN TAFS AS THE LLJ INCREASES TO AROUND 50 KNOTS
LATE TONIGHT.
CONVECTION BECOMES A CONCERN FOR THE EVENING AND LATE NIGHT IN THE
NORTH DUE TO ABUNDANT SBCAPE...MAINLY 2000-3000J/KG...AND PLENTY
OF LOW-LEVEL AND DEEP-LAYER WIND SHEAR. THE PRESENCE OF 150-300J/KG
OF CIN MAKES DEVELOPMENT LESS LIKELY...BUT THE CAP MAY END UP
GETTING BROKEN BY THE SURFACE BOUNDARY. HAVE ONLY USED A PROB30 AT
RHI TO COVER THIS POSSIBILITY. IF STORMS DO DEVELOP...THERE IS A
PRETTY GOOD CHANCE THAT SEVERE WEATHER WILL OCCUR.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MG
LONG TERM......TE
AVIATION.......MG
AREA FORECAST DISCUSSION
NWS PUEBLO CO
338 AM MDT WED SEP 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM MDT WED SEP 11 2013
THE UPR LOW IS EXPECTED TO BE CENTERED OVR THE SWRN CORNER OF UT
TODAY AND MAYBE MOVING SLIGHTLY NORTHWARD OVERNIGHT. MODELS ARE
SHOWING THE PLUME OF UPR MSTR SHIFTING EASTWARD THRU THE DAY AND
MAINLY BEING OVR THE EASTERN PORTIONS OF THE FORECAST AREA THIS
AFTERNOON...AND THEN BEING OVR THE FAR SERN PLAINS TONIGHT. WV
IMAGERY THIS MORNING SHOWING THE DRIER AIR WORKING ITS WAY INTO SWRN
CO. CURRENT RADAR LOOP SHOWING SOME ISOLD TO SCT ECHOES OVR THE SAN
LUIS VALLEY AND ALONG THE CONTDVD...WITH MORE PCPN OVR ERN AREAS AND
ADDITIONAL PCPN WORKING ITS WAY NORTHWARD FROM EASTERN NM.
IN GENERAL...THE HRRR SHOWS MAINLY ISOLD TO SCT POPS OVR THE SAN
LUIS VALLEY AND ALONG THE CONTDVD TODAY...WITH SCT OR HIGHER POPS
FROM THE ERN MTS TO THE ERN BORDER. THE WRF IS SIMILAR...ALTHOUGH IT
SHOWS HIGHER POPS OVR THE HIGHER TRRN IN THE MORNING HOURS...AND
THEN DECREASES THE PCPN CHANCES FOR THE AFTERNOON HOURS ALONG THE
CONTDVD AND SAN LUIS VALLEY AS THE DRIER AIR MOVES SPREADS OVR THE
AREA. THE NAM LOOKS OVERDONE AGAIN IN TERMS OF PCPN ACCUMULATION OVR
THE ERN MTS AND I-25 CORRIDOR FOR THE MORNING HOURS. BASED ON THE
WRF AND HRRR...PCPN OVR THE BURN SCARS TODAY SHOULD MOSTLY BE HIT
OR MISS AND NOT A PROLONGED EVENT...WL NOT ISSUE A FLASH FLOODING
HIGHLIGHT. HOWEVER THERE IS STILL THE CHANCE FOR LOCALLY HEAVY
RAIN AND THE STEERING FLOW TODAY IS EXPECTED TO BE ONLY AROUND
10-15 KTS OVR THE ERN MTS AND I-25 CORRIDOR...THUS FLASH FLOODING
CANNOT BE RULED OUT IF A STRONG SLOW MOVING STORM WERE TO MOVE OVR
AREA BURN SCARS. TEMPS OVR THE MTN PEAKS WL AGAIN BE COLD ENOUGH
FOR SOME SNOW TO OCCUR WITH SOME LIGHT ACCUMULATIONS.
FOR TONIGHT...ALL MODELS BRING DRIER CONDITIONS TO THE WESTERN HALF
OF THE FORECAST AREA...WITH SOME PCPN CONTINUING THRU THE NIGHT OVR
PORTIONS OF THE ERN PLAINS...ESPECIALLY THE FAR EASTERN AREAS AS A
COUPLE DISTURBANCES MOVES ACRS THAT AREA.
|
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 333 AM MDT WED SEP 11 2013
...WET THROUGH SUNDAY...
...DRYING OUT NEXT WEEK...
WET FORECAST REMAINS ON TRACK. WETTEST PERIOD STILL LOOKS TO BE THU
INTO FRI OF THIS WEEK...WHEN THE UPPER LOW IS MOVING THROUGH WRN UT
AND ERN NV...AND UPSLOPE WILL BE MAXIMIZED OVER THE ERN CO PLAINS.
THE ERN MTS...IN PARTICULAR THE ERN SLOPES...WILL LIKELY SEE THE
MOST QPF FROM THIS EVENT. THE NAM12 IS STILL PROGGING 2-4 INCHES OF
LIQUID FOR THE SRN FRONT RANGE AND PIKES PEAK REGION. PRETTY MUCH
THE ENTIRE AREA SHOULD SEE AN INCH OF RAIN OR BETTER OVER THE NEXT
SEVERAL DAYS. THE EXCEPTIONS COULD BE THE SAN LUIS VALLEY AND
PORTIONS OF THE ARKANSAS CANYON...WHICH COULD BE SHELTERED SOMEWHAT
WITH THESE SPOTS NOT AS CONDUCIVE TO UPSLOPE PRECIP. PORTIONS OF THE
FAR ERN PLAINS MIGHT ALSO SEE A BIT MORE SPOTTY TOTALS...SINCE THE
PRECIP THERE WILL BE A BIT MORE DEPENDENT ON WHERE CONVECTION SETS
UP. THE HIGHEST AMTS SHOULD BE OVR THE SRN SANGRES...RATON
MESA...AND PALMER DVD AND PIKES PEAK AREA. BURN SCARS IN THIS AREA
WILL BE THE MAIN CONCERN THROUGH THE WEEKEND.
TEMPS SHOULD STAY ON THE COOL SIDE...IN THE 60S AND 70S...THRU
FRIDAY...THEN REBOUND A BIT ON SATURDAY BEFORE ANOTHER FRONT MOVES
THROUGH ON SUN AND KNOCKS THINGS DOWN BELOW AVG AGAIN. POPS WILL
ALSO INCREASE AGAIN ON SUNDAY AS THE NEXT FRONT ARRIVES. SNOW LEVELS
REMAIN RELATIVELY HIGH THROUGH THE END OF THE WEEK...BUT AS
MENTIONED PREVIOUSLY THE HIGHEST ELEVS ABOVE 13K FT OR SO WILL SEE
SOME ACCUMULATING SNOW...PERHAPS QUITE A BIT FOR THE HIGHEST SUMMITS.
BY THE WEEKEND...SNOW LEVELS SHOULD DROP TO AS LOW AS 12K FEET...AND
THIS COULD GIVE THE ERN MTS A GOOD SHOT OF SNOW BY THE END OF THE
WEEKEND.
NEXT WEEK...THE PATTERN WILL BE DOMINATED BY A PROGRESSIVE UPPER LOW
MOVING OUT OF THE PACNW TUE-WED...AND THEN QUICKLY THROUGH THE NRN
ROCKIES ON THU. MOST OF OUR AREA WILL BE TO THE SOUTH OF THE MAIN
CIRCULATION...SO THE PLAINS WILL LIKELY STAY MAINLY DRY AND PERHAPS
A BIT BREEZY. THE MTS COULD SEE SOME OROGRAPHIC PRECIP...BUT MAY SEE
MORE WIND THAN RAIN/SNOW UNLESS THE LOW TRACKS A BIT FARTHER S THAN
THE MODELS CURRENTLY INDICATE. TEMPS SHOULD ALSO CLIMB BACK TO ABOVE
AVG FOR THE PLAINS...POSSIBLY REACHING THE MID 80S OR HIGHER BY
WED-THU. ROSE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 333 AM MDT WED SEP 11 2013
PCPN IS WORKING ITS WAY NORTHWARD THIS MORNING AND SHOULD BRING
SHOWERS TO KCOS AND KPUB...WITH THE POTENTIAL FOR MVFR CONDITIONS
AND MAYBE EVEN SOME BRIEF IFR CONDITIONS AT KCOS. KALS WL ALSO
HAVE SOME LIGHT RAIN IN THE VCNTY THRU THE MORNING. THIS AFTERNOON
AND EVENING THE THREE TERMINAL SITE COULD HAVE TSTMS IN THE AREA.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...28
LONG TERM...ROSE
AVIATION...28
AREA FORECAST DISCUSSION
NWS ALBANY NY
159 AM EDT WED SEP 11 2013
.SYNOPSIS...
IN THE WAKE OF A WARM FRONT...CLOUDS WILL CONTINUE TO
BREAK UP OVER THE REGION THIS EVENING WITH MILDER AND MUGGY WEATHER
IN PLACE. HOT TEMPERATURES ARE EXPECTED TOMORROW WITH PARTIAL
SUNSHINE...HUMID CONDITIONS...AND A CHANCE FOR A SHOWER OR
THUNDERSTORM. A STRONG COLD FRONT...ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS...WILL MOVE ACROSS THE REGION THURSDAY
USHERING IN A MUCH COOLER AND LESS HUMID AUTUMN AIR MASS FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1215 AM EDT...MAINLY CLEAR SKIES AND MUGGY CONDITIONS
ACROSS THE REGION. THERE HAS BEEN AN INCREASE IN LOW CLOUDS/FOG
PER THE 11U-3.9U ENHANCED IR SATELLITE IMAGERY THIS EVENING COMING
DOWN THE CHAMPLAIN VALLEY AND ADDITIONAL FOG/STRATUS ALONG WITH
HAZE IS EXPECTED OVERNIGHT. HAVE RAISED OVERNIGHT LOWS A COUPLE OF
DEGREES IN SEVERAL LOCATIONS...EXCEPT FOR LAKE GEORGE AND GLENS
FALLS REGIONS WHERE WE LOWERED THEM A BIT MORE PER OBSERVATIONS
AND MESONET OBS. OVERNIGHT LOWS ARE EXPECTED TO RANGE FROM THE MID
60S TO MID 70S.
00Z SOUNDINGS WERE QUITE UNSTABLE IN THE MID LEVELS BUT WITH A LACK
OF A TRIGGER IN THE H2O VAPOR AND HOURLY RUC ANALYSIS...CONTINUED
WITH A DRY FORECAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
OUR REGION WILL FIRMLY BE IN THE WARM SECTOR TOMORROW. AFTER ANY
MORNING FOG BREAKS UP...PARTIAL SUNSHINE ALONG WITH 850 HPA TEMPS
OF AROUND 20 DEGREES C WILL YIELD MAX TEMPS IN VALLEY AREAS TO
REACH AROUND 90 DEGREES...WITH 80S ACROSS THE HIGH TERRAIN.
THERE WON/T BE MUCH OF A LARGE SCALE FORCING MECHANISM FOR
SHOWER/THUNDERSTORM DEVELOPMENT TOMORROW...BUT THERE STILL
PROBABLY WILL BE ISOLD TO SCT THUNDERSTORMS DURING THE AFTN AND
EVENING HOURS THANKS TO A PRE FRONTAL TROUGH AND/OR TERRAIN
FORCING. WITH THE WARM AND MUGGY AIR MASS IN PLACE...INSTABILITY
WILL BE HIGH /SBCAPE VALUES ARE PROJECTED TO BE WELL OVER 2000
J/KG/ AND 0-6 KM BULK SHEAR VALUES OF 20-35 KTS LOOK TO BE MORE
THAN SUFFICIENT FOR STORMS TO DEVELOP AND ORGANIZE. SPC HAS PLACED
MUCH OF OUR AREA IN A SLIGHT RISK FOR SVR STORMS AND WE WILL
LIKELY NEED TO MONITOR ANY CONVECTION VERY CLOSELY. DAMAGING WINDS
WOULD BE THE PRIMARY THREAT WITH ANY STORMS. IN ADDITION...HIGH
PWATS/DEWPOINTS WILL ALLOW FOR HVR DOWNPOURS WITHIN ANY T-STORM.
THE THREAT FOR CONVECTION WILL CONTINUE INTO WED NIGHT AS AN
UPSTREAM TROUGH OVER THE GREAT LAKES AND ASSOCIATED SFC COLD FRONT
BEGINS TO HEAD TOWARDS OUR AREA. IT WILL REMAIN MUGGY AND WARM ALL
NIGHT WITH MINS IN THE MID 60S TO NEAR 70...STICKY
CONDITIONS...AND A MOSTLY CLOUDY SKY. THE MAIN THREAT WILL BE ACROSS
THE FAR NORTHWESTERN PART OF THE CWA.
ON THURSDAY INTO THURSDAY NIGHT...THE COLD FRONT WILL BE MOVING
ACROSS OUR AREA...PROVIDING PLENTY OF FORCING FOR LIFT.
INSTABILITY WON/T BE AS ROBUST AS WEDNESDAY THANKS TO MORE CLOUD
COVER...BUT THE STRONG FORCING SHOULD BE ENOUGH TO ALLOW FOR A FEW
LINES OF SHOWERS AND THUNDERSTORMS TO MOVE FROM WEST TO EAST
ACROSS THE AREA. WE WILL GO WITH LIKELY POPS FOR
SHOWERS/THUNDERSTORMS FOR THURSDAY INTO THURSDAY EVENING. SPC HAS
A PORTION OF OUR AREA IN SLIGHT RISK FOR SVR STORMS AGAIN ON
THURSDAY AS WELL. POPS WILL LOWER THURSDAY NIGHT FROM WEST TO EAST
WITH THE PASSAGE OF THE SFC BOUNDARY...WHICH WILL START TO BRING
LESS HUMID AIR INTO THE REGION. TEMPS ON THURSDAY LOOK TO BE IN
THE LOW 80S FOR VALLEY AREAS...WITH MINS IN THE 50S AND 60S FOR
THURS NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A RATHER PROGRESSIVE AND AMPLIFIED PATTERN IS EXPECTED FOR THE LONG
TERM PORTION OF THIS FORECAST AS SEVERAL PERTURBATIONS WITHIN THE
NORTHWEST FLOW REGIME WILL IMPACT OUR REGION.
WE BEGIN WITH FRIDAY AS THE MAIN COLD FRONT AND MOISTURE IS EXPECTED
TO BE EAST OF THE REGION AS WE ARE LEFT WITH A CYCLONIC
FLOW/EMBEDDED UPPER LOW OVER THE EASTERN GREAT LAKES AND NEW
ENGLAND. AS THOSE H850 TEMPS DROP BACK INTO THE LOWER SINGLE
DIGITS...THIS WILL ALLOW FOR LAKE CONTRIBUTIONS TO INCREASE AS WELL
AS THE CHC-SCT SHOWERS MAINLY ACROSS THE HIGHER TERRAIN. AS
CONSIDERABLE CLOUD COVER IS EXPECTED AND MAINLY TERRAIN BASED...WE
WILL SEE HIGH TEMPERATURES MUCH COOLER WITH MAINLY 60S...SOME 50S
FOR THE HIGHER TERRAIN AND ACROSS THE ADIRONDACKS.
THE LOSS OF DIURNAL HEATING WILL RESULT IN A DECREASE IN CLOUDS AND
SHOWERS FRIDAY EVENING. HOWEVER...THE MAIN UPPER LOW IS EXPECTED TO
REMAIN RATHER SLOW MOVING PER THE GLOBAL MODEL CONSENSUS WHICH WILL
SET THE STAGE FOR ANOTHER ROUND OF TERRAIN BASED CLOUD COVER DURING
SATURDAY. THERE IS SOME QUESTION ON JUST HOW MUCH INSTABILITY WILL
BE AROUND FOR SHOWERS AS WE WILL KEEP POPS JUST BELOW SLIGHT CHANCE
AS TRENDS PER THE DPROG/DT FAVOR A DRIER SOLUTION AT THIS TIME.
HIGHS REMAIN BELOW NORMAL WITH MAINLY 50S ACROSS THE TERRAIN AND
LOWER HALF OF THE 60S FOR VALLEY LOCATIONS.
ANOTHER FAST MOVING DISTURBANCE IN THE NORTHWEST FLOW REGIME IS
FORECAST TO APPROACH LATE SUNDAY INTO SUNDAY NIGHT. MOISTURE ALONG
THIS BOUNDARY REMAINS LIMITED BUT LAKE MOISTURE CONTRIBUTION WILL
ADD THE CHANCE FOR SOME SHOWERS MAINLY NORTH AND WEST OF ALBANY.
WINDS ARE EXPECTED TO INCREASE IN THE WAKE OF THE FROPA ON MONDAY AS
THOSE H850 TEMPS DROP BACK INTO THE LOWER SINGLE DIGITS AS A LARGE
CANADIAN HIGH PRESSURE SYSTEM MOVES ACROSS THE GREAT LAKES REGION.
HIGHS WILL REMAIN IN THE 60S.
OVERALL...PCPN AND TEMPS LOOK BELOW NORMAL IN THE EXTEND FORECAST
PERIOD.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
A WARM AND HUMID AIR MASS CONTINUES TO IMPACT THE REGION THIS
MORNING INTO THE AFTERNOON. A WEAK MID LEVEL DISTURBANCE IN THE
W/SW FLOW ALOFT MAY PRODUCE ISOLD-SCT SHOWERS AND THUNDERSTORMS
IN THE LATE AFTERNOON. A COLD FRONT WILL INCREASE THE COVERAGE OF
SHOWERS AND THUNDERSTORMS WED NIGHT INTO THU.
THE CLEAR SKIES AND LIGHT TO CALM WINDS HAVE LET RADIATIONAL
MIST/FOG FORM AT KGFL/KPSF/KPOU. SOME LOW STRATUS IN THE LIFR/IFR
RANGE IS ALSO LIKELY. THE FOG WILL BECOME DENSER BTWN 08Z-14Z.
KALB CONTINUES TO HAVE A LIGHT SOUTHERLY WIND...BUT A BRIEF PERIOD
OF MVFR VSBYS/CIGS IS POSSIBLE BTWN 08-12Z...AND A TEMPO GROUP HAS
BEEN USED TO ADDRESS THIS POSSIBILITY.
A GRADUAL IMPROVEMENT TO VFR LEVELS WILL OCCUR AT KPOU/KPSF/KGFL
BTWN 14Z-16Z. VFR CONDITIONS WILL OCCUR INTO THE MID PM...AND THEN
THAT MID LEVEL DISTURBANCE OR SFC TROUGH COULD FOCUS THE ISOLD-SCT
SHOWERS AND THUNDERSTORMS. VCSH GROUPS HAVE BEEN USED AT THIS
TIME. CIG BASES WILL BE IN THE 4-5 KFT AGL RANGE. THE SKIES SHOULD
CLEAR A BIT AFTER 00Z/THU...THIS MAY ALLOW FOR SOME PATCH MIST
AGAIN...ESPECIALLY AT KPSF AND KGFL.
THE WINDS WILL BE LIGHT AND VARIABLE AT LESS THAN 5 KTS AT ALL THE
TAF SITES...EXCEPT AT KALB WHERE A LIGHT S WIND OF 4-7 KTS WILL
CONTINUE THIS MORNING. THE WINDS WILL INCREASE FROM THE SOUTH TO
SOUTHWEST AT 8 TO 13 KTS DURING THE PM...WITH A FEW GUSTS AROUND
20-25 KTS AT KALB/KPSF. THE WINDS WILL LIGHTEN TO LESS THAN 7 KTS
AFTER 01Z/THU.
OUTLOOK...
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THURSDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
FRIDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
FRIDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY TO SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED ISSUES ARE ANTICIPATED OVER THE NEXT
SEVERAL DAYS.
A WARM FRONT WILL CONTINUE TO MOVE THROUGH THE REGION THIS
EVENING...BRING MUGGY CONDITIONS IN ITS WAKE. THERE WILL BE A THREAT
FOR SHOWERS AND THUNDERSTORMS TOMORROW AND ESPECIALLY AGAIN ON
THURSDAY AS OUR REGION WILL BE IN A WARM AND MUGGY AIR MASS AHEAD OF
AN APPROACHING COLD FRONT. RH VALUES WILL BE HIGH AT NIGHT...NEARLY
100 PERCENT AT TIMES. RH VALUES WILL ONLY DROP TO 50 TO 60 PERCENT
DURING THE DAYTIME HOURS.
&&
.HYDROLOGY...
THERE WILL BE A THREAT FOR SHOWERS AND THUNDERSTORMS OVER THE
SEVERAL DAYS. OUR REGION WILL BE IN A WARM SECTOR TOMORROW BEFORE
A STRONG COLD FRONT MOVES THROUGH ON THURSDAY. PWAT VALUES WILL
BE QUITE HIGH OVER THE NEXT FEW DAYS...WITH PWAT VALUES 1.50 TO
2.00 INCHES. THIS WILL ALLOW FOR ANY SHOWER OR THUNDERSTORM TO BE
CAPABLE OF PRODUCING VERY HEAVY RAINFALL IN A SHORT PERIOD OF
TIME. THUNDERSTORMS LOOK TO BE MOST WIDESPREAD ON THURSDAY AHEAD OF
THE ADVANCING COLD FRONT. THE THREAT FOR HEAVY SHOWERS AND
THUNDERSTORMS WILL END WITH THE PASSAGE OF THE COLD FRONT LATE
THURSDAY...WITH MUCH DRIER AND LESS HUMID WEATHER FOR THE LATE
WEEK PERIOD.
WITHIN ANY SHOWER OR THUNDERSTORM...THERE WILL BE THE POTENTIAL FOR
MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS DUE TO
VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME. WHILE WIDESPREAD MAIN
STEM RIVER FLOODING IS NOT ANTICIPATED OVER THE NEXT FEW
DAYS...THERE WILL BE SOME POTENTIAL FOR FLOODING OF SMALL CREEKS AND
STREAMS DUE TO THE THUNDERSTORM ACTIVITY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/BGM/11
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...WASULA
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
1221 AM EDT WED SEP 11 2013
.SYNOPSIS...
IN THE WAKE OF A WARM FRONT...CLOUDS WILL CONTINUE TO
BREAK UP OVER THE REGION THIS EVENING WITH MILDER AND MUGGY WEATHER
IN PLACE. HOT TEMPERATURES ARE EXPECTED TOMORROW WITH PARTIAL
SUNSHINE...HUMID CONDITIONS...AND A CHANCE FOR A SHOWER OR
THUNDERSTORM. A STRONG COLD FRONT...ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS...WILL MOVE ACROSS THE REGION THURSDAY
USHERING IN A MUCH COOLER AND LESS HUMID AUTUMN AIR MASS FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1215 AM EDT...MAINLY CLEAR SKIES AND MUGGY CONDITIONS
ACROSS THE REGION. THERE HAS BEEN AN INCREASE IN LOW CLOUDS/FOG
PER THE 11U-3.9U ENHANCED IR SATELLITE IMAGERY THIS EVENING COMING
DOWN THE CHAMPLAIN VALLEY AND ADDITIONAL FOG/STRATUS ALONG WITH
HAZE IS EXPECTED OVERNIGHT. HAVE RAISED OVERNIGHT LOWS A COUPLE OF
DEGREES IN SEVERAL LOCATIONS...EXCEPT FOR LAKE GEORGE AND GLENS
FALLS REGIONS WHERE WE LOWERED THEM A BIT MORE PER OBSERVATIONS
AND MESONET OBS. OVERNIGHT LOWS ARE EXPECTED TO RANGE FROM THE MID
60S TO MID 70S.
00Z SOUNDINGS WERE QUITE UNSTABLE IN THE MID LEVELS BUT WITH A LACK
OF A TRIGGER IN THE H2O VAPOR AND HOURLY RUC ANALYSIS...CONTINUED
WITH A DRY FORECAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
OUR REGION WILL FIRMLY BE IN THE WARM SECTOR TOMORROW. AFTER ANY
MORNING FOG BREAKS UP...PARTIAL SUNSHINE ALONG WITH 850 HPA TEMPS
OF AROUND 20 DEGREES C WILL YIELD MAX TEMPS IN VALLEY AREAS TO
REACH AROUND 90 DEGREES...WITH 80S ACROSS THE HIGH TERRAIN.
THERE WON/T BE MUCH OF A LARGE SCALE FORCING MECHANISM FOR
SHOWER/THUNDERSTORM DEVELOPMENT TOMORROW...BUT THERE STILL
PROBABLY WILL BE ISOLD TO SCT THUNDERSTORMS DURING THE AFTN AND
EVENING HOURS THANKS TO A PRE FRONTAL TROUGH AND/OR TERRAIN
FORCING. WITH THE WARM AND MUGGY AIR MASS IN PLACE...INSTABILITY
WILL BE HIGH /SBCAPE VALUES ARE PROJECTED TO BE WELL OVER 2000
J/KG/ AND 0-6 KM BULK SHEAR VALUES OF 20-35 KTS LOOK TO BE MORE
THAN SUFFICIENT FOR STORMS TO DEVELOP AND ORGANIZE. SPC HAS PLACED
MUCH OF OUR AREA IN A SLIGHT RISK FOR SVR STORMS AND WE WILL
LIKELY NEED TO MONITOR ANY CONVECTION VERY CLOSELY. DAMAGING WINDS
WOULD BE THE PRIMARY THREAT WITH ANY STORMS. IN ADDITION...HIGH
PWATS/DEWPOINTS WILL ALLOW FOR HVR DOWNPOURS WITHIN ANY T-STORM.
THE THREAT FOR CONVECTION WILL CONTINUE INTO WED NIGHT AS AN
UPSTREAM TROUGH OVER THE GREAT LAKES AND ASSOCIATED SFC COLD FRONT
BEGINS TO HEAD TOWARDS OUR AREA. IT WILL REMAIN MUGGY AND WARM ALL
NIGHT WITH MINS IN THE MID 60S TO NEAR 70...STICKY
CONDITIONS...AND A MOSTLY CLOUDY SKY. THE MAIN THREAT WILL BE ACROSS
THE FAR NORTHWESTERN PART OF THE CWA.
ON THURSDAY INTO THURSDAY NIGHT...THE COLD FRONT WILL BE MOVING
ACROSS OUR AREA...PROVIDING PLENTY OF FORCING FOR LIFT.
INSTABILITY WON/T BE AS ROBUST AS WEDNESDAY THANKS TO MORE CLOUD
COVER...BUT THE STRONG FORCING SHOULD BE ENOUGH TO ALLOW FOR A FEW
LINES OF SHOWERS AND THUNDERSTORMS TO MOVE FROM WEST TO EAST
ACROSS THE AREA. WE WILL GO WITH LIKELY POPS FOR
SHOWERS/THUNDERSTORMS FOR THURSDAY INTO THURSDAY EVENING. SPC HAS
A PORTION OF OUR AREA IN SLIGHT RISK FOR SVR STORMS AGAIN ON
THURSDAY AS WELL. POPS WILL LOWER THURSDAY NIGHT FROM WEST TO EAST
WITH THE PASSAGE OF THE SFC BOUNDARY...WHICH WILL START TO BRING
LESS HUMID AIR INTO THE REGION. TEMPS ON THURSDAY LOOK TO BE IN
THE LOW 80S FOR VALLEY AREAS...WITH MINS IN THE 50S AND 60S FOR
THURS NIGHT.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
A RATHER PROGRESSIVE AND AMPLIFIED PATTERN IS EXPECTED FOR THE LONG
TERM PORTION OF THIS FORECAST AS SEVERAL PERTURBATIONS WITHIN THE
NORTHWEST FLOW REGIME WILL IMPACT OUR REGION.
WE BEGIN WITH FRIDAY AS THE MAIN COLD FRONT AND MOISTURE IS EXPECTED
TO BE EAST OF THE REGION AS WE ARE LEFT WITH A CYCLONIC
FLOW/EMBEDDED UPPER LOW OVER THE EASTERN GREAT LAKES AND NEW
ENGLAND. AS THOSE H850 TEMPS DROP BACK INTO THE LOWER SINGLE
DIGITS...THIS WILL ALLOW FOR LAKE CONTRIBUTIONS TO INCREASE AS WELL
AS THE CHC-SCT SHOWERS MAINLY ACROSS THE HIGHER TERRAIN. AS
CONSIDERABLE CLOUD COVER IS EXPECTED AND MAINLY TERRAIN BASED...WE
WILL SEE HIGH TEMPERATURES MUCH COOLER WITH MAINLY 60S...SOME 50S
FOR THE HIGHER TERRAIN AND ACROSS THE ADIRONDACKS.
THE LOSS OF DIURNAL HEATING WILL RESULT IN A DECREASE IN CLOUDS AND
SHOWERS FRIDAY EVENING. HOWEVER...THE MAIN UPPER LOW IS EXPECTED TO
REMAIN RATHER SLOW MOVING PER THE GLOBAL MODEL CONSENSUS WHICH WILL
SET THE STAGE FOR ANOTHER ROUND OF TERRAIN BASED CLOUD COVER DURING
SATURDAY. THERE IS SOME QUESTION ON JUST HOW MUCH INSTABILITY WILL
BE AROUND FOR SHOWERS AS WE WILL KEEP POPS JUST BELOW SLIGHT CHANCE
AS TRENDS PER THE DPROG/DT FAVOR A DRIER SOLUTION AT THIS TIME.
HIGHS REMAIN BELOW NORMAL WITH MAINLY 50S ACROSS THE TERRAIN AND
LOWER HALF OF THE 60S FOR VALLEY LOCATIONS.
ANOTHER FAST MOVING DISTURBANCE IN THE NORTHWEST FLOW REGIME IS
FORECAST TO APPROACH LATE SUNDAY INTO SUNDAY NIGHT. MOISTURE ALONG
THIS BOUNDARY REMAINS LIMITED BUT LAKE MOISTURE CONTRIBUTION WILL
ADD THE CHANCE FOR SOME SHOWERS MAINLY NORTH AND WEST OF ALBANY.
WINDS ARE EXPECTED TO INCREASE IN THE WAKE OF THE FROPA ON MONDAY AS
THOSE H850 TEMPS DROP BACK INTO THE LOWER SINGLE DIGITS AS A LARGE
CANADIAN HIGH PRESSURE SYSTEM MOVES ACROSS THE GREAT LAKES REGION.
HIGHS WILL REMAIN IN THE 60S.
OVERALL...PCPN AND TEMPS LOOK BELOW NORMAL IN THE EXTEND FORECAST
PERIOD.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
HAZE AND FOG WILL IMPACT FLIGHT CONDITIONS TONIGHT AS MOST OF THE
CLOUDS HAVE EXITED OR DISSIPATED ACROSS THE TAF SITES.
HOWEVER...ENHANCEMENT OF THE IR SATELLITE IMAGERY DOES REVEAL SOME
LOWER CLOUDS ACROSS WESTERN NEW ENGLAND. AS DEWPOINT DEPRESSIONS
CONTINUE TO COLLAPSE...EXPECTATIONS ARE FOR SOME IFR CONDITIONS TO
DEVELOP AND HAVE PLACED THIS INTO THE TAFS OVERNIGHT. A LIGHT
SOUTHERLY WIND WILL PERSIST AND INCREASE THROUGH THE DAYLIGHT
HOURS WEDNESDAY WHICH WILL IMPROVE FLIGHT CONDITIONS TO VFR.
THE CHANCE FOR SOME ISO-SCT CONVECTION INCREASES IN THE AFTERNOON
AND HAVE PLACE VCSH AT THIS TIME.
OUTLOOK...
WEDNESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
THURSDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
THURSDAY NIGHT: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
FRIDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
FRIDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED ISSUES ARE ANTICIPATED OVER THE NEXT
SEVERAL DAYS.
A WARM FRONT WILL CONTINUE TO MOVE THROUGH THE REGION THIS
EVENING...BRING MUGGY CONDITIONS IN ITS WAKE. THERE WILL BE A THREAT
FOR SHOWERS AND THUNDERSTORMS TOMORROW AND ESPECIALLY AGAIN ON
THURSDAY AS OUR REGION WILL BE IN A WARM AND MUGGY AIR MASS AHEAD OF
AN APPROACHING COLD FRONT. RH VALUES WILL BE HIGH AT NIGHT...NEARLY
100 PERCENT AT TIMES. RH VALUES WILL ONLY DROP TO 50 TO 60 PERCENT
DURING THE DAYTIME HOURS.
&&
.HYDROLOGY...
THERE WILL BE A THREAT FOR SHOWERS AND THUNDERSTORMS OVER THE
SEVERAL DAYS. OUR REGION WILL BE IN A WARM SECTOR TOMORROW BEFORE
A STRONG COLD FRONT MOVES THROUGH ON THURSDAY. PWAT VALUES WILL
BE QUITE HIGH OVER THE NEXT FEW DAYS...WITH PWAT VALUES 1.50 TO
2.00 INCHES. THIS WILL ALLOW FOR ANY SHOWER OR THUNDERSTORM TO BE
CAPABLE OF PRODUCING VERY HEAVY RAINFALL IN A SHORT PERIOD OF
TIME. THUNDERSTORMS LOOK TO BE MOST WIDESPREAD ON THURSDAY AHEAD OF
THE ADVANCING COLD FRONT. THE THREAT FOR HEAVY SHOWERS AND
THUNDERSTORMS WILL END WITH THE PASSAGE OF THE COLD FRONT LATE
THURSDAY...WITH MUCH DRIER AND LESS HUMID WEATHER FOR THE LATE
WEEK PERIOD.
WITHIN ANY SHOWER OR THUNDERSTORM...THERE WILL BE THE POTENTIAL FOR
MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS DUE TO
VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME. WHILE WIDESPREAD MAIN
STEM RIVER FLOODING IS NOT ANTICIPATED OVER THE NEXT FEW
DAYS...THERE WILL BE SOME POTENTIAL FOR FLOODING OF SMALL CREEKS AND
STREAMS DUE TO THE THUNDERSTORM ACTIVITY.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/BGM/11
SHORT TERM...FRUGIS
LONG TERM...BGM
AVIATION...IAA/BGM
FIRE WEATHER...FRUGIS
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
319 AM EDT Wed Sep 11 2013
.SHORT TERM (Now through Thursday)...
Issued at 310 AM EDT Wed Sep 11 2013
This morning area obs show light patchy fog. Expect this light fog
to continue to develop and persist through the pre-dawn hours
especially in fog prone areas and locations where it rained
yesterday. Don`t expect to see any dense fog as winds aloft are
mixy.
For the rest of the day, expect convection to develop this morning
over southwest Indiana/southern IL/western KY and spread eastward
through the morning hours to at least Louisville/Bowling Green and
then closer to Lexington by early afternoon. Did go ahead and bump
up timing on POPs based on 0Z NAM and latest RAP guidance. These
models did a good job with yesterday`s convection, and both seem to
agree with an area of moisture convergence and isentropic lift
developing early this morning to kick off storms. This matches SPC
deep moisture convergence mesoanalysis well. Once convection gets
going, the environment looks favorable for strong storms similar to
yesterday. The strongest storms may contain wind gusts up to 40
mph, torrential rainfall, and frequent lightning. Slow storm
motions today combined with heavy rainfall may cause minor flooding
issues especially in areas that received a lot of rainfall
yesterday. With anticipated convection a little earlier than
previously thought, did go on the cooler side of temps for highs
today especially over central KY which will probably be cloudy or
rainy much of the late morning and afternoon hours. Southern
Indiana may clear out early enough to cause temps to rebound near
peak heating. Therefore will go with a gradient of lower 90s across
southern Indiana to mid 80s over portions of central KY.
Expect a dry period tonight as today`s convection will decline with
the loss of diurnal heating/instability. Low temps will remain mild
in the upper 60s and lower 70s.
For Thurs, a cold front will cross the area bringing sct-numerous
storms. With good instability and better wind shear along the base
of an upper level trough, we`ll likely see better storm
organization. With 0-6 km bulk shear values ranging from 25-35 kts,
multicells and perhaps some bowing segments may be possible. Steep
lapse rates and dry lower levels are supportive of a damaging wind
threat. As previously mentioned, though, the bulk of the better
wind shear values looks to lag behind the main line of convection
limiting the possibility for widespread damaging winds. Still will
need to keep an eye on the potential for severe storms Thurs. With
PWATs remaining high, storms will likely contain torrential rainfall
although they should have more movement to them than storms today.
Frequent lightning will also be likely. With the front gradually
making it`s way south through the area on Thurs providing for plenty
of clouds and on and off convection, temps should be limited to the
mid 80s for highs.
.LONG TERM (Thursday night through Tuesday)...
Issued at 313 AM EDT Wed Sep 11 2013
Thursday night - Sunday night:
A big cooldown is coming this weekend after the passage of a cold
front Thursday/Thursday night. Have left some lingering chances for
precip in the forecast for the beginning half of Thursday night
primarily for southern KY as the front makes its way south and out
of the forecast area. By sunrise Friday morning, the rain will have
completely exited, leaving skies to clear and much cooler temps
behind. Afternoon highs are currently forecast to range from the low
to mid 70s, continuing on the same track of utilizing raw model
guidance as did the previous forecaster. Regardless of exactly how
cool highs will be for both Friday and Saturday, NCEP 850mb
temperature ensemble guidance clearly depicts the probability of
below normal anomalies at or greater than 1 standard deviation. As
surface high pressure of Canadian origin settles in over the Ohio
Valley by Saturday, have gone just a couple of degrees cooler on
Saturday versus Friday, which means that portions of the Bluegrass
region could potentially struggle to reach the 70 degree mark. Am a
little concerned that this could be a bit too low but given the
lowering sun angles for this time of year and the fact that we are
inching closer to autumn, am sticking with the raw model guidance
currently provided. This means that under plenty of nighttime
radiational cooling, lows will flirt with the 50 degree mark for
Friday and Saturday night with some notoriously cooler spots
potentially dipping down into the upper 40s. Will certainly need to
continue to monitor model trends and the incoming CAA to nail down
specific highs and lows. By Sunday, the strong surface high will
begin to weaken its grip over the Ohio Valley and traverse eastward,
off of the eastern seaboard. This allows for southerly flow to
recommence and will begin to be felt as highs on Sunday reach the
upper 70s. Sunday night lows will respond, only dropping into the
upper 50s to lower 60s.
Monday - Tuesday night:
Models diverge from each other for this time period as the ECMWF
shows a stronger upper ridge over the Deep South extending into our
neck of the woods whereas the GFS generally keeps us under zonal
flow at the 500mb level with slight perturbations rippling through
early next week. At the surface, it appears as though the region
could see the next fropa coming through on Monday but then
potentially stalling out in the vicinity of the KY-TN border.
Significant differences temporally and spatially yield a low
confidence forecast at this juncture. A few members of the GEFS hint
at precip on Monday and given that we`ll see an uptick in
lower-level moisture under southerly flow, cannot entirely rule out
the possibility of at least diurnally-driven convection on Monday
afternoon and have therefore introduced slight chance PoPs as such.
Have kept Tuesday/Tuesday night dry area-wide for now as the front
potentially remains to the south of the forecast area. Temps look to
rebound to near normal for this time frame.
&&
.AVIATION (06Z TAF Update)...
Issued at 135 AM EDT Wed Sep 11 2013
The first TAF concern will be light patchy fog near BWG/LEX this
morning. Both terminals have experienced lowering vsbys early this
morning and should continue to gradually lower into the MVFR cat
through the early morning hours. Think that mixy winds just off the
sfc will prevent any vsbys lower than MVFR.
The next concern for all TAF sites will be convection chances for
today. Greater convective coverage is expected over the area today,
however, with storms still anticipated to be scattered in nature
will hold off on VCTS mention. Will go ahead and use VCSH to
highlight the best time period for possible convection though. 0Z
NAM and latest high-res model guidance has trended earlier with
convective development for today. According to these models
showers/storms should develop near the I-65 corridor on the nose of
good isentropic lift aloft after sunrise this morning and push
eastward throughout the afternoon hours. Thus will highlight mid
morning through the afternoon for BWG/SDF for convection chances and
mainly just the afternoon hours for LEX. Will probably try to pin
down t-storm chances at the 12Z issuance should newest model data
and environmental data continue to support early convective
develop. Will need to address any possible fog concerns for
tomorrow morning with the 12Z TAF issuance as well.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........AMS
Long Term.........lg
Aviation..........AMS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
516 AM EDT WED SEP 11 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...A SHORTWAVE MOVING ACROSS
NRN ONTARIO AND LAKE SUPERIOR THIS AFTERNOON COMBINED WITH UPR DIV
IN RIGHT ENTRANCE REGION OF ASSOC 100+ KT 3H JET HAVE HELPED SUSTAIN
A COUPLE DIFFERENT BATCHES OF SHRA WHICH HAVE MOVED OVER THE WEST
HALF OF UPPER MI THIS AFTERNOON. UPSLOPE FOG WHICH PLAGUED THE
KEWEENAW INTO THE EARLY AFTERNOON HOURS LOOKS LIKE IT HAS FINALLY
LIFTED PER SFC OBS AND WEB CAMS BUT STRATUS CLOUDS STILL REMAIN. AT
THE SFC...A COUPLE OF SFC TROUGHS EXTEND FM LOW PRES CENTERED NE OF
LAKE SUPERIOR...ONE TROUGH EXTENDS INTO ERN AND SCNTRL UPR MI WHILE
ANOTHER IS STILL SITUATED OVER FAR NRN LAKE SUPERIOR AND ONTARIO.
TONIGHT...EXPECT AREA OF SHOWERS NOW EXTENDING FM IRON COUNTY INTO
WRN MQT COUNTY TO MOVE SLOWLY EAST OVER THE NEXT COUPLE OF HOURS AND
THEN GRADUALLY DISSIPATE THIS EVENING AS 700-650 MB FGEN SLOWLY
WEAKENS. THERE IS A CONCERN THAT A STRONG TO POSSIBLY SVR STORM
COULD FORM OVER THE ERN HALF OF UPPER MI IN THE NEXT FEW HOURS.
PARTIAL SUNSHINE HAS ALLOWED MLCAPES TO BUILD UP TO AROUND 2000
J/KG. THIS ALONG WITH EFFECTIVE SHEAR OF 50-60 KT AND ENHANCED
CONVERGENCE ALONG SFC TROUGH COULD TRIGGER STORMS OVER ERN UPPER MI
LATE AFTERNOON INTO EARLY EVENING. THIS WILL NEED TO BE CLOSELY
MONITORED ON THE EVENING SHIFT.
THE OTHER CONCERN TONIGHT IS THE POTENTIAL FOR MORE FOG TO FORM LATE
EVENING INTO OVERNIGHT HRS AS TEMPS RADIATE THROUGH UPPER 50S/LOWER
60S DEWPOINTS UNDER LIGHT WINDS AND PARTIAL CLEARING. HAVE EXPANDED
MENTION OF PATCHY TO AREAS OF FOG ACROSS THE CWA AND WOULD NOT BE
SURPRISED TO SEE SOME LOCALLY DENSE FOG AT SOME LOCATIONS.
WEDNESDAY...ANOTHER SHORTWAVE NOW DROPPING DOWN FROM NRN
SASKATCHEWAN/NRN MANITOBA WILL HELP PUSH FRONTAL BOUNDARY INTO THE
AREA. SCNTRL AND ERN UPR MI WILL AGAIN HAVE BEST CHC OF AFTERNOON
SHRA/TSRA AS MLCAPES ARE FCST BY MODELS TO INCREASE TO 500-1000
J/KG. WILL INCLUDE HIGHER CHC 40 PCT POPS OVER THIS AREA. WITH WEAK
DOWNSLOPE WRLY FLOW INTO THE BAY OF GREEN BAY...EXPECT THE WARMEST
HIGH TEMPS (LOWER TO MID 80S) OVER MNM COUNTY. ELSEWHERE MAX TEMPS
WILL GENERALLY BE IN THE 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 438 AM EDT WED SEP 11 2013
THRU MUCH OF THE LONG TERM...PATTERN WILL CONTINUE TO BE ONE THAT
HAS BEEN COMMON IN RECENT WEEKS...A MEAN RIDGE OVER NW CANADA AND A
MEAN TROF OVER ERN N AMERICA. TOWARD THE END OF THE LONG TERM AND
INTO LATE NEXT WEEK...IT APPEARS A TROF WILL REPLACE THE NW CANADA
RIDGE. THIS COULD SPELL A PERIOD OF WARM WEATHER JUST BEYOND THE
LONG TERM. PRIOR TO THAT...MEDIUM RANGE GUIDANCE HAS AND CONTINUES
TO POINT TO 2 PERIODS WHEN THE ERN TROF WILL AMPLIFY. THE FIRST
OCCURS THU/FRI WITH THE SECOND FOLLOWING QUICKLY OVER THE WEEKEND.
SOME SHRA MAY ACCOMPANY EACH AMPLIFICATION...BUT OVERALL...THIS WILL
BE A DRY PATTERN WITH NO WIDESPREAD/SIGNIFICANT PCPN IN THE OFFING
DURING THE LONG TERM PORTION OF THE FCST. AS FOR TEMPS...THE 2
AMPLIFICATIONS OF THE ERN TROF WILL BRING 2 SHOTS OF COLD AIR INTO
THE UPPER LAKES...SENDING TEMPS BLO NORMAL AND BRINGING A REAL TASTE
OF AUTUMN TO THE AREA. BY MON...MANY INTERIOR LOCATIONS SHOULD HAVE
SEEN AT LEAST ONE NIGHT WITH SOME FROST...AND TRADITIONAL COLD SPOTS
WILL PROBABLY HAVE SEEN AT LEAST ONE NIGHT WITH A FREEZE.
BEGINNING THU...CAA PATTERN WILL BE WELL UNDERWAY AND WILL CONTINUE
THRU THE DAY AS A PAIR OF SHORTWAVES AMPLIFY THE TROF INTO THE GREAT
LAKES REGION. BY 00Z FRI...850MB TEMPS COULD BE HOVERING AROUND 0C
OVER NRN AND ERN UPPER MI. WITH SECOND OF THE 2 SHORTWAVES TRACKING
OVER FAR WRN UPPER MI...MUCH OF THE FCST AREA WILL BE ON THE
CYCLONIC SIDE OF THE SHORTWAVE TRACK/ASSOCIATED UPPER JET STREAK...
FAVORABLE FOR SCT SHRA. MODELS SHOW A BAND OF DEEP LAYER QVECTOR
CONVERGENCE PUSHING ACROSS THE AREA RIGHT WHERE IT WOULD BE EXPECTED
ON THE CYCLONIC SIDE OF THE JET STREAK/SHORTWAVE. SO...SCT SHRA LOOK
LIKE A PRETTY GOOD BET THU...ESPECIALLY OVER THE ERN 2/3RDS OF THE
FCST AREA. WITH 850MB TEMPS FALLING TO AROUND 0C ACROSS CNTRL AND
ERN LAKE SUPERIOR DURING THE TIME OF SYNOPTIC FORCING...THERE WILL
BE SOME LAKE COMPONENT TO THE SHRA...BUT REALLY MORE OF A HYBRID
TYPE COMPONENT AS STILL STRONG DAYTIME HEATING DISRUPTS NORMAL LAKE
EFFECT PROCESSES. END RESULT WILL BE MORE SHRA ACTIVITY INLAND
THAN OVER THE LAKE. OTHERWISE...THU WILL BE A COOL DAY WITH GUSTY
N/NW WINDS AND ABUNDANT CLOUD COVER. TEMPS WILL LIKELY NOT GET OUT
OF THE MID/UPPER 50S ACROSS THE N.
WITH LOSS OF DISRUPTING DAYTIME HEATING...THERE MAY BE AN UPTICK
IN MORE TRADITIONAL LOOKING LAKE EFFECT -SHRA THU NIGHT...MAINLY
OVER THE CNTRL/E UNDER NRLY FLOW WITH 850MB TEMPS FALLING TO -2 OR
-3C. HOWEVER...DEEP LAYER QVECTOR DIVERGENCE/SUBSIDENCE AND A WELL
MIXED BOUNDARY LAYER/INVERTED V LOOK ON FCST SOUNDINGS SUGGEST -SHRA
ACTIVITY PROBABLY WON`T REALLY BE MUCH MORE THAN ISOLD. ATTENTION
THEN TURNS TO FROST POTENTIAL OVER THE W. WITH HIGH PRES STILL
BUILDING TOWARD UPPER MI FROM THE NW...THERE ARE CONCERNS OVER LAKE
EFFECT CLOUD COVER. MODEL GUIDANCE SHOWS DIVERGENT LOW-LEVEL NNE
WINDS OVER THE W WHICH SUGGESTS CLOUDS MAY CLEAR OUT DURING THE
NIGHT. WILL RETAIN IDEA OF CLOUDS AT LEAST PARTIALLY CLEARING OVER
THE FAR W...ALLOWING TEMPS TO FALL INTO THE MID/UPPER 30S WITH
POTENTIAL FOR PATCHY FROST. CLOUDS WILL GRADUALLY CLEAR FROM W TO E
FRI AS SFC HIGH SETTLES INTO UPPER MI. FRI WILL BE COOL WITH HIGHS
MOSTLY IN THE MID TO UPPER 50S.
FRI NIGHT OFFERS A GOOD OPPORTUNITY FOR WIDESPREAD FROST AND ALSO A
POTENTIAL FREEZE IN SOME AREAS. HOWEVER...WITH SFC HIGH QUICKLY
EXITING TO THE SE...RETURN FLOW WILL BE DEVELOPING...PREVENTING
IDEAL RADIATIONAL COOLING THRU THE NIGHT. PRECIPITABLE WATER AROUND
50PCT OF NORMAL AND CLEAR SKIES/CALM WIND AT LEAST INITIALLY WILL
ALLOW FOR A QUICK TEMP DROP FRI EVENING...AND THIS MAY BE ENOUGH TO
RESULT IN WIDESPREAD FROST ACROSS THE INTERIOR. THE BEST CHANCE FOR
FROST AND EVEN SOME FREEZING CONDITIONS WILL BE OVER THE E AND S...
CLOSER TO DEPARTING SFC HIGH WHICH WILL ALLOW A LONGER PERIOD OF
CALM WIND. WILL INCLUDE SOME SUBFREEZING TEMPS INTO THE UPPER 20S IN
THE TRADITIONAL COLD SPOTS OVER THE E.
AS THE HIGH CONTINUES TO MOVE SE SAT AND THE NEXT SHORTWAVE/COLD
FRONT APPROACH FROM THE NW...SW WINDS WILL BRING A GOOD PUSH OF
WARMER AIR INTO THE UPPER LAKES (850MB TEMPS RETURN TO AROUND 10C).
MIXING TO AROUND 850MB YIELDS HIGHS BACK UP TO AROUND NORMAL IN THE
MID 60S TO AROUND 70F UNDER A GOOD DISPLAY OF SUNSHINE...AT LEAST FOR
THE FIRST HALF OF THE DAY.
THE NEXT SHORTWAVE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
AREA SAT NIGHT INTO SUN MORNING. THERE ARE ONLY MINOR TIMING
DIFFERENCES AMONG MEDIUM RANGE GUIDANCE. THE GFS HAS SHOWN VERY GOOD
CONTINUITY OVER THE LAST 4 RUNS...AND THE LATEST RUN IS IN GOOD
AGREEMENT WITH THE GEM/ECMWF. CONSENUS OF GUIDANCE INCLUDING
PREVIOUS GFS RUNS PLACES COLD FRONT BISECTING UPPER MI AT 12Z SUN.
WITH TRACK OF SHORTWAVE PASSING JUST N AND E OF THE FCST AREA...
BETTER POTENTIAL FOR PCPN WILL BE OFF TO THE N AND E OF HERE. ONLY
SCHC/LOW CHC POPS WILL CONTINUE TO BE UTILIZED...MAINLY OVERNIGHT
SAT NIGHT INTO SUN MORNING.
850MB TEMPS DON`T DROP QUITE AS MUCH AS THE PREVIOUS COLD SHOT
THU/FRI...SO POTENTIAL OF LAKE EFFECT CLOUDS/SHRA FOR SUN NIGHT INTO
MON WON`T BE AS GREAT. IN FACT...LAKE EFFECT -SHRA LOOK DOUBTFUL AT
THIS POINT. SFC HIGH SETTLING OVER THE AREA SUN NIGHT WITH DRY AIR
MASS (PRECIPITABLE WATER AROUND 50PCT OF NORMAL) WILL BRING ANOTHER
CHILLY NIGHT WITH FROST AND POSSIBLE FREEZING CONDITIONS IN THE
INTERIOR. FAVORED LOW END OF AVBL GUIDANCE FOR MIN TEMPS SUN NIGHT.
A SUNNY DAY WILL FOLLOW FOR MON. COULD BE SOME FROST CONCERNS AGAIN
MON NIGHT...DEPENDING ON HOW FAST SFC HIGH DEPARTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 141 AM EDT WED SEP 11 2013
EXPECT FOG AT ALL SITES INTO EARLY THIS MORNING...BUT EXACT COVERAGE
AND EXTENT OF FOG REMAINS UNCERTAIN. THERE IS A HIGH POTENTIAL THAT
THE EXISTING CLOUDS OVERHEAD AND TO OUR SW WILL LINGER
OVERHEAD...REDUCING THE POTENTIAL FOR SIGNIFICANT FOG. WILL LIKELY
NEED TO MAKE A FEW ADJUSTMENTS TO THE ONGOING TAFS OVERNIGHT. A COLD
FRONT WILL MOVE THROUGH THIS AFTERNOON/EVENING...AND SOME CONVECTION
IS EXPECTED ALONG THE FRONT. HAVE THE HIGHEST CONFIDENCE OF
CONVECTION AT SAW...SO INCLUDED VCSH THERE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 516 AM EDT WED SEP 11 2013
LOW PRESSURE ACROSS NORTH CENTRAL ONTARIO WILL DRAG A TROUGH/COLD
FRONT ACROSS LAKE SUPERIOR TODAY...BEFORE THE LOW SINKS ACROSS JAMES
BAY THIS EVENING AND EXITS ACROSS THE QUEBEC ON THURSDAY. IN THE
WAKE OF THE LOW...LARGE HIGH PRESSURE STRETCHING FROM CENTRAL CANADA
THROUGH THE NORTHERN PLAINS WILL SLOWLY SINK ACROSS THE UPPER GREAT
LAKES THURSDAY NIGHT THROUGH FRIDAY NIGHT. N TO NNW WINDS WILL GUST
20-30KTS THURSDAY THROUGH THURSDAY NIGHT. A FEW HIGHER PLATFORMS
COULD EXPERIENCE GALE FORCE GUSTS.
EXPECT THE HIGH PRESSURE SYSTEM TO PUSH SOUTHEASTWARD ON
SATURDAY...MAKING WAY FOR LOW PRESSURE ACROSS HUDSON BAY ON SATURDAY
TO DRAG ANOTHER TROUGH OVER LAKE SUPERIOR SATURDAY NIGHT INTO EARLY
SUNDAY. SW WINDS COULD GUST INTO THE 20-25KT RANGE SATURDAY. ANOTHER
AREA OF HIGH PRESSURE WILL SINK IN LATE SUNDAY FROM THE NORTHWEST
/WITH NW GUSTS OF 20-25KTS SUNDAY/.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...ROLFSON
AVIATION...JT/KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
439 AM EDT WED SEP 11 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...A SHORTWAVE MOVING ACROSS
NRN ONTARIO AND LAKE SUPERIOR THIS AFTERNOON COMBINED WITH UPR DIV
IN RIGHT ENTRANCE REGION OF ASSOC 100+ KT 3H JET HAVE HELPED SUSTAIN
A COUPLE DIFFERENT BATCHES OF SHRA WHICH HAVE MOVED OVER THE WEST
HALF OF UPPER MI THIS AFTERNOON. UPSLOPE FOG WHICH PLAGUED THE
KEWEENAW INTO THE EARLY AFTERNOON HOURS LOOKS LIKE IT HAS FINALLY
LIFTED PER SFC OBS AND WEB CAMS BUT STRATUS CLOUDS STILL REMAIN. AT
THE SFC...A COUPLE OF SFC TROUGHS EXTEND FM LOW PRES CENTERED NE OF
LAKE SUPERIOR...ONE TROUGH EXTENDS INTO ERN AND SCNTRL UPR MI WHILE
ANOTHER IS STILL SITUATED OVER FAR NRN LAKE SUPERIOR AND ONTARIO.
TONIGHT...EXPECT AREA OF SHOWERS NOW EXTENDING FM IRON COUNTY INTO
WRN MQT COUNTY TO MOVE SLOWLY EAST OVER THE NEXT COUPLE OF HOURS AND
THEN GRADUALLY DISSIPATE THIS EVENING AS 700-650 MB FGEN SLOWLY
WEAKENS. THERE IS A CONCERN THAT A STRONG TO POSSIBLY SVR STORM
COULD FORM OVER THE ERN HALF OF UPPER MI IN THE NEXT FEW HOURS.
PARTIAL SUNSHINE HAS ALLOWED MLCAPES TO BUILD UP TO AROUND 2000
J/KG. THIS ALONG WITH EFFECTIVE SHEAR OF 50-60 KT AND ENHANCED
CONVERGENCE ALONG SFC TROUGH COULD TRIGGER STORMS OVER ERN UPPER MI
LATE AFTERNOON INTO EARLY EVENING. THIS WILL NEED TO BE CLOSELY
MONITORED ON THE EVENING SHIFT.
THE OTHER CONCERN TONIGHT IS THE POTENTIAL FOR MORE FOG TO FORM LATE
EVENING INTO OVERNIGHT HRS AS TEMPS RADIATE THROUGH UPPER 50S/LOWER
60S DEWPOINTS UNDER LIGHT WINDS AND PARTIAL CLEARING. HAVE EXPANDED
MENTION OF PATCHY TO AREAS OF FOG ACROSS THE CWA AND WOULD NOT BE
SURPRISED TO SEE SOME LOCALLY DENSE FOG AT SOME LOCATIONS.
WEDNESDAY...ANOTHER SHORTWAVE NOW DROPPING DOWN FROM NRN
SASKATCHEWAN/NRN MANITOBA WILL HELP PUSH FRONTAL BOUNDARY INTO THE
AREA. SCNTRL AND ERN UPR MI WILL AGAIN HAVE BEST CHC OF AFTERNOON
SHRA/TSRA AS MLCAPES ARE FCST BY MODELS TO INCREASE TO 500-1000
J/KG. WILL INCLUDE HIGHER CHC 40 PCT POPS OVER THIS AREA. WITH WEAK
DOWNSLOPE WRLY FLOW INTO THE BAY OF GREEN BAY...EXPECT THE WARMEST
HIGH TEMPS (LOWER TO MID 80S) OVER MNM COUNTY. ELSEWHERE MAX TEMPS
WILL GENERALLY BE IN THE 70S.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 438 AM EDT WED SEP 11 2013
THRU MUCH OF THE LONG TERM...PATTERN WILL CONTINUE TO BE ONE THAT
HAS BEEN COMMON IN RECENT WEEKS...A MEAN RIDGE OVER NW CANADA AND A
MEAN TROF OVER ERN N AMERICA. TOWARD THE END OF THE LONG TERM AND
INTO LATE NEXT WEEK...IT APPEARS A TROF WILL REPLACE THE NW CANADA
RIDGE. THIS COULD SPELL A PERIOD OF WARM WEATHER JUST BEYOND THE
LONG TERM. PRIOR TO THAT...MEDIUM RANGE GUIDANCE HAS AND CONTINUES
TO POINT TO 2 PERIODS WHEN THE ERN TROF WILL AMPLIFY. THE FIRST
OCCURS THU/FRI WITH THE SECOND FOLLOWING QUICKLY OVER THE WEEKEND.
SOME SHRA MAY ACCOMPANY EACH AMPLIFICATION...BUT OVERALL...THIS WILL
BE A DRY PATTERN WITH NO WIDESPREAD/SIGNIFICANT PCPN IN THE OFFING
DURING THE LONG TERM PORTION OF THE FCST. AS FOR TEMPS...THE 2
AMPLIFICATIONS OF THE ERN TROF WILL BRING 2 SHOTS OF COLD AIR INTO
THE UPPER LAKES...SENDING TEMPS BLO NORMAL AND BRINGING A REAL TASTE
OF AUTUMN TO THE AREA. BY MON...MANY INTERIOR LOCATIONS SHOULD HAVE
SEEN AT LEAST ONE NIGHT WITH SOME FROST...AND TRADITIONAL COLD SPOTS
WILL PROBABLY HAVE SEEN AT LEAST ONE NIGHT WITH A FREEZE.
BEGINNING THU...CAA PATTERN WILL BE WELL UNDERWAY AND WILL CONTINUE
THRU THE DAY AS A PAIR OF SHORTWAVES AMPLIFY THE TROF INTO THE GREAT
LAKES REGION. BY 00Z FRI...850MB TEMPS COULD BE HOVERING AROUND 0C
OVER NRN AND ERN UPPER MI. WITH SECOND OF THE 2 SHORTWAVES TRACKING
OVER FAR WRN UPPER MI...MUCH OF THE FCST AREA WILL BE ON THE
CYCLONIC SIDE OF THE SHORTWAVE TRACK/ASSOCIATED UPPER JET STREAK...
FAVORABLE FOR SCT SHRA. MODELS SHOW A BAND OF DEEP LAYER QVECTOR
CONVERGENCE PUSHING ACROSS THE AREA RIGHT WHERE IT WOULD BE EXPECTED
ON THE CYCLONIC SIDE OF THE JET STREAK/SHORTWAVE. SO...SCT SHRA LOOK
LIKE A PRETTY GOOD BET THU...ESPECIALLY OVER THE ERN 2/3RDS OF THE
FCST AREA. WITH 850MB TEMPS FALLING TO AROUND 0C ACROSS CNTRL AND
ERN LAKE SUPERIOR DURING THE TIME OF SYNOPTIC FORCING...THERE WILL
BE SOME LAKE COMPONENT TO THE SHRA...BUT REALLY MORE OF A HYBRID
TYPE COMPONENT AS STILL STRONG DAYTIME HEATING DISRUPTS NORMAL LAKE
EFFECT PROCESSES. END RESULT WILL BE MORE SHRA ACTIVITY INLAND
THAN OVER THE LAKE. OTHERWISE...THU WILL BE A COOL DAY WITH GUSTY
N/NW WINDS AND ABUNDANT CLOUD COVER. TEMPS WILL LIKELY NOT GET OUT
OF THE MID/UPPER 50S ACROSS THE N.
WITH LOSS OF DISRUPTING DAYTIME HEATING...THERE MAY BE AN UPTICK
IN MORE TRADITIONAL LOOKING LAKE EFFECT -SHRA THU NIGHT...MAINLY
OVER THE CNTRL/E UNDER NRLY FLOW WITH 850MB TEMPS FALLING TO -2 OR
-3C. HOWEVER...DEEP LAYER QVECTOR DIVERGENCE/SUBSIDENCE AND A WELL
MIXED BOUNDARY LAYER/INVERTED V LOOK ON FCST SOUNDINGS SUGGEST -SHRA
ACTIVITY PROBABLY WON`T REALLY BE MUCH MORE THAN ISOLD. ATTENTION
THEN TURNS TO FROST POTENTIAL OVER THE W. WITH HIGH PRES STILL
BUILDING TOWARD UPPER MI FROM THE NW...THERE ARE CONCERNS OVER LAKE
EFFECT CLOUD COVER. MODEL GUIDANCE SHOWS DIVERGENT LOW-LEVEL NNE
WINDS OVER THE W WHICH SUGGESTS CLOUDS MAY CLEAR OUT DURING THE
NIGHT. WILL RETAIN IDEA OF CLOUDS AT LEAST PARTIALLY CLEARING OVER
THE FAR W...ALLOWING TEMPS TO FALL INTO THE MID/UPPER 30S WITH
POTENTIAL FOR PATCHY FROST. CLOUDS WILL GRADUALLY CLEAR FROM W TO E
FRI AS SFC HIGH SETTLES INTO UPPER MI. FRI WILL BE COOL WITH HIGHS
MOSTLY IN THE MID TO UPPER 50S.
FRI NIGHT OFFERS A GOOD OPPORTUNITY FOR WIDESPREAD FROST AND ALSO A
POTENTIAL FREEZE IN SOME AREAS. HOWEVER...WITH SFC HIGH QUICKLY
EXITING TO THE SE...RETURN FLOW WILL BE DEVELOPING...PREVENTING
IDEAL RADIATIONAL COOLING THRU THE NIGHT. PRECIPITABLE WATER AROUND
50PCT OF NORMAL AND CLEAR SKIES/CALM WIND AT LEAST INITIALLY WILL
ALLOW FOR A QUICK TEMP DROP FRI EVENING...AND THIS MAY BE ENOUGH TO
RESULT IN WIDESPREAD FROST ACROSS THE INTERIOR. THE BEST CHANCE FOR
FROST AND EVEN SOME FREEZING CONDITIONS WILL BE OVER THE E AND S...
CLOSER TO DEPARTING SFC HIGH WHICH WILL ALLOW A LONGER PERIOD OF
CALM WIND. WILL INCLUDE SOME SUBFREEZING TEMPS INTO THE UPPER 20S IN
THE TRADITIONAL COLD SPOTS OVER THE E.
AS THE HIGH CONTINUES TO MOVE SE SAT AND THE NEXT SHORTWAVE/COLD
FRONT APPROACH FROM THE NW...SW WINDS WILL BRING A GOOD PUSH OF
WARMER AIR INTO THE UPPER LAKES (850MB TEMPS RETURN TO AROUND 10C).
MIXING TO AROUND 850MB YIELDS HIGHS BACK UP TO AROUND NORMAL IN THE
MID 60S TO AROUND 70F UNDER A GOOD DISPLAY OF SUNSHINE...AT LEAST FOR
THE FIRST HALF OF THE DAY.
THE NEXT SHORTWAVE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
AREA SAT NIGHT INTO SUN MORNING. THERE ARE ONLY MINOR TIMING
DIFFERENCES AMONG MEDIUM RANGE GUIDANCE. THE GFS HAS SHOWN VERY GOOD
CONTINUITY OVER THE LAST 4 RUNS...AND THE LATEST RUN IS IN GOOD
AGREEMENT WITH THE GEM/ECMWF. CONSENUS OF GUIDANCE INCLUDING
PREVIOUS GFS RUNS PLACES COLD FRONT BISECTING UPPER MI AT 12Z SUN.
WITH TRACK OF SHORTWAVE PASSING JUST N AND E OF THE FCST AREA...
BETTER POTENTIAL FOR PCPN WILL BE OFF TO THE N AND E OF HERE. ONLY
SCHC/LOW CHC POPS WILL CONTINUE TO BE UTILIZED...MAINLY OVERNIGHT
SAT NIGHT INTO SUN MORNING.
850MB TEMPS DON`T DROP QUITE AS MUCH AS THE PREVIOUS COLD SHOT
THU/FRI...SO POTENTIAL OF LAKE EFFECT CLOUDS/SHRA FOR SUN NIGHT INTO
MON WON`T BE AS GREAT. IN FACT...LAKE EFFECT -SHRA LOOK DOUBTFUL AT
THIS POINT. SFC HIGH SETTLING OVER THE AREA SUN NIGHT WITH DRY AIR
MASS (PRECIPITABLE WATER AROUND 50PCT OF NORMAL) WILL BRING ANOTHER
CHILLY NIGHT WITH FROST AND POSSIBLE FREEZING CONDITIONS IN THE
INTERIOR. FAVORED LOW END OF AVBL GUIDANCE FOR MIN TEMPS SUN NIGHT.
A SUNNY DAY WILL FOLLOW FOR MON. COULD BE SOME FROST CONCERNS AGAIN
MON NIGHT...DEPENDING ON HOW FAST SFC HIGH DEPARTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 141 AM EDT WED SEP 11 2013
EXPECT FOG AT ALL SITES INTO EARLY THIS MORNING...BUT EXACT COVERAGE
AND EXTENT OF FOG REMAINS UNCERTAIN. THERE IS A HIGH POTENTIAL THAT
THE EXISTING CLOUDS OVERHEAD AND TO OUR SW WILL LINGER
OVERHEAD...REDUCING THE POTENTIAL FOR SIGNIFICANT FOG. WILL LIKELY
NEED TO MAKE A FEW ADJUSTMENTS TO THE ONGOING TAFS OVERNIGHT. A COLD
FRONT WILL MOVE THROUGH THIS AFTERNOON/EVENING...AND SOME CONVECTION
IS EXPECTED ALONG THE FRONT. HAVE THE HIGHEST CONFIDENCE OF
CONVECTION AT SAW...SO INCLUDED VCSH THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE INTO THIS EVENING AS
DRIER AIR WORKS IN FROM THE NORTH. WEAK HIGH PRESSURE THIS EVENING
WILL BE REPLACED BY A BROAD TROUGH THAT WILL BE EXTENDING SOUTHWARD
FROM NORTHERN ONTARIO LATE TONIGHT THROUGH EARLY WEDNESDAY EVENING.
A LARGE HIGH PRESSURE ENCOMPASSING MUCH OF S CENTRAL CANADA AND THE
N PLAINS WEDNESDAY NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES
AND THE E COAST FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST
WINDS OVER LAKE SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE LATE
WEDNESDAY NIGHT THROUGH EARLY FRIDAY MORNING...WITH N GUSTS OF
20-30KTS CENTERED ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...ROLFSON
AVIATION...JT/KF
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
144 AM EDT WED SEP 11 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...A SHORTWAVE MOVING ACROSS
NRN ONTARIO AND LAKE SUPERIOR THIS AFTERNOON COMBINED WITH UPR DIV
IN RIGHT ENTRANCE REGION OF ASSOC 100+ KT 3H JET HAVE HELPED SUSTAIN
A COUPLE DIFFERENT BATCHES OF SHRA WHICH HAVE MOVED OVER THE WEST
HALF OF UPPER MI THIS AFTERNOON. UPSLOPE FOG WHICH PLAGUED THE
KEWEENAW INTO THE EARLY AFTERNOON HOURS LOOKS LIKE IT HAS FINALLY
LIFTED PER SFC OBS AND WEB CAMS BUT STRATUS CLOUDS STILL REMAIN. AT
THE SFC...A COUPLE OF SFC TROUGHS EXTEND FM LOW PRES CENTERED NE OF
LAKE SUPERIOR...ONE TROUGH EXTENDS INTO ERN AND SCNTRL UPR MI WHILE
ANOTHER IS STILL SITUATED OVER FAR NRN LAKE SUPERIOR AND ONTARIO.
TONIGHT...EXPECT AREA OF SHOWERS NOW EXTENDING FM IRON COUNTY INTO
WRN MQT COUNTY TO MOVE SLOWLY EAST OVER THE NEXT COUPLE OF HOURS AND
THEN GRADUALLY DISSIPATE THIS EVENING AS 700-650 MB FGEN SLOWLY
WEAKENS. THERE IS A CONCERN THAT A STRONG TO POSSIBLY SVR STORM
COULD FORM OVER THE ERN HALF OF UPPER MI IN THE NEXT FEW HOURS.
PARTIAL SUNSHINE HAS ALLOWED MLCAPES TO BUILD UP TO AROUND 2000
J/KG. THIS ALONG WITH EFFECTIVE SHEAR OF 50-60 KT AND ENHANCED
CONVERGENCE ALONG SFC TROUGH COULD TRIGGER STORMS OVER ERN UPPER MI
LATE AFTERNOON INTO EARLY EVENING. THIS WILL NEED TO BE CLOSELY
MONITORED ON THE EVENING SHIFT.
THE OTHER CONCERN TONIGHT IS THE POTENTIAL FOR MORE FOG TO FORM LATE
EVENING INTO OVERNIGHT HRS AS TEMPS RADIATE THROUGH UPPER 50S/LOWER
60S DEWPOINTS UNDER LIGHT WINDS AND PARTIAL CLEARING. HAVE EXPANDED
MENTION OF PATCHY TO AREAS OF FOG ACROSS THE CWA AND WOULD NOT BE
SURPRISED TO SEE SOME LOCALLY DENSE FOG AT SOME LOCATIONS.
WEDNESDAY...ANOTHER SHORTWAVE NOW DROPPING DOWN FROM NRN
SASKATCHEWAN/NRN MANITOBA WILL HELP PUSH FRONTAL BOUNDARY INTO THE
AREA. SCNTRL AND ERN UPR MI WILL AGAIN HAVE BEST CHC OF AFTERNOON
SHRA/TSRA AS MLCAPES ARE FCST BY MODELS TO INCREASE TO 500-1000
J/KG. WILL INCLUDE HIGHER CHC 40 PCT POPS OVER THIS AREA. WITH WEAK
DOWNSLOPE WRLY FLOW INTO THE BAY OF GREEN BAY...EXPECT THE WARMEST
HIGH TEMPS (LOWER TO MID 80S) OVER MNM COUNTY. ELSEWHERE MAX TEMPS
WILL GENERALLY BE IN THE 70S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 408 PM EDT TUE SEP 10 2013
COLD FRONT WILL BE DEPARTING THE CWA AT THE START OF THE LONG TERM
PERIOD...WHILE A POTENT SHORTWAVE DROPS SOUTHEAST ACROSS THE UPPER
GREAT LAKES REGION. THE MAIN PRECIPITATION WITH THE COLD
FRONT WILL BE SLIDING SOUTHEAST OVER THE EASTERN CWA TO START THE
PERIOD. BEHIND THIS...THERE SHOULD BE A QUICK BREAK TO THE
PRECIPITATION BEFORE COLDER AIR AND ABUNDANT LOW LEVEL MOISTURE
SURGES SOUTH ACROSS LAKE SUPERIOR LATE WEDNESDAY NIGHT INTO THURSDAY
ON THE EAST SIDE OF THE HIGH MOVING INTO THE NORTHERN PLAINS.
THUS...WOULD EXPECT A PERIOD OF PARTLY CLOUDY SKIES FOR A TIME
WEDNESDAY NIGHT BEFORE THE 850MB TEMPS FALL TO 0C BETWEEN 18Z
THURSDAY TO 00Z FRIDAY. SINCE LAKE SUPERIOR TEMPS ARE AROUND
12-16C...THIS INCREASING COLD AIR WILL PUSH DELTA T VALUES TOWARDS
FAVORABLE LAKE EFFECT RAIN SHOWERS AND CLOUDS. THE INVERSION HEIGHT
IS RIGHT AROUND 825MB OR 4.5KFT...SO THAT WILL LIMIT THE CLOUD DEPTH
FOR STRONGER SHOWERS...BUT STILL THINK THERE WILL BE ENOUGH AROUND
FOR ISOLATED/SCATTERED MENTION IN THE FAVORED NORTH-NORTHWEST WIND
LOCATIONS. WILL RAMP UP THE POPS THROUGH THE DAY AS THE COLDEST AIR
AND BEST MOISTURE ARRIVES IN THE AFTERNOON AND EARLY EVENING.
IT IS STARTING TO LOOK LIKE THE CLOUDS WILL LINGER LONGER ON
THURSDAY NIGHT...WHICH BRINGS THE LOW FORECAST AND FROST
POTENTIAL INTO QUESTION. OPTED TO TREND TEMPS AND CLOUDS UP SOME
THROUGH THE NIGHT. THE BEST OPPORTUNITY FOR BREAKS IN THE CLOUDS
LOOKS TO BE OVER THE VERY FAR WEST (GOGEBIC/ONTONAGON COUNTIES) AND
WILL KEEP THE COLDEST TEMPERATURES THERE. THIS LONGER LASTING
MOISTURE CALLS FOR THE CLOUDS TO HANG ON INTO AT LEAST FRIDAY
MORNING AND HAVE TRENDED THE SKY FORECAST UP SIGNIFICANTLY FOR THAT
TIME. ALSO DELAYED THE END OF THE SHOWER CHANCES INTO THE MORNING
FOR LOCATIONS FROM MARQUETTE EASTWARD. ALL OF THE MODELS ARE SHOWING
THE MOISTURE DIMINISHING FROM WEST TO EAST DURING THE AFTERNOON AS
THE HIGH MOVES OVER THE CWA. HIGHS ON FRIDAY WILL BE FAIRLY
COOL...WITH HIGHS IN THE MID AND UPPER 50S.
THIS HIGH WILL LEAD TO A VERY CHILLY NIGHT ON FRIDAY NIGHT. SINCE
WINDS WILL BECOME CALM...SKIES WILL BE CLEAR...AND PWATS ARE AROUND
40-45 PERCENT OF NORMAL...EXPECT A GOOD RADIATIONAL COOLING NIGHT.
FORECAST HAS BEEN HITTING THE POTENTIAL FOR FROST ON FRIDAY NIGHT
AND THAT CONTINUES TO SEEM REASONABLE. DID TREND LOWS DOWN A COUPLE
DEGREES OVER THE INTERIOR LOCATIONS AND IT APPEARS LIKE THERE WILL
BE A DECENT OPPORTUNITY FOR FROST IN THAT AREA WITH LOWS IN THE MID
30S. SOME OF THE TRADITIONAL COLD SPOTS OVER THE CENTRAL/EAST MAY
EVEN FALL BELOW FREEZING FOR AWHILE.
THE HIGH WILL SHIFT SOUTHEAST ON SATURDAY AND INCREASING SOUTHERLY
FLOW WILL PUSH TEMPERATURES BACK TOWARDS NORMAL AND AROUND . WITH
10 DEGREES WARMER THAN FRIDAY. THE AREA UNDER A RIDGE ALOFT...EXPECT
A MOSTLY SUNNY DAY ON SATURDAY.
THE NEXT SHORTWAVE AND ASSOCIATED COLD FRONT WILL MOVE ACROSS THE
AREA SATURDAY NIGHT INTO SUNDAY MORNING. THE 12Z MODEL RUNS OF
THE ECMWF/GFS/GEM HAVE COME INTO DECENT AGREEMENT WITH THE
TRACK OF THE SHORTWAVE BRUSHING THE UPPER GREAT LAKES REGION
AND THUS THE TIMING/LOCATION OF THE FRONT AND PRECIPITATION.
SINCE THE MAIN FORCING/MOISTURE LOOKS TO TRACK ACROSS
NORTHEAST LAKE SUPERIOR...HAVE TRENDED POPS DOWN SOMEWHAT AND
TOWARDS SLIGHT CHANCE AND LOW CHANCE POPS. COLD AIR
WILL ONLY BRUSH THE AREA BEHIND THIS FRONT...SO THINK THE POTENTIAL
FOR LAKE ENHANCED CLOUDS/SHOWERS FOR SUNDAY NIGHT INTO MONDAY LOOKS
TO BE LESS LIKELY THAN SHOWN ON YESTERDAY/S RUNS. HIGH PRESSURE
BUILDS IN FOR MONDAY AND MONDAY NIGHT AND SHOULD LEAD TO DRY WEATHER
FOR THE START OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 141 AM EDT WED SEP 11 2013
EXPECT FOG AT ALL SITES INTO EARLY THIS MORNING...BUT EXACT COVERAGE
AND EXTENT OF FOG REMAINS UNCERTAIN. THERE IS A HIGH POTENTIAL THAT
THE EXISTING CLOUDS OVERHEAD AND TO OUR SW WILL LINGER
OVERHEAD...REDUCING THE POTENTIAL FOR SIGNIFICANT FOG. WILL LIKELY
NEED TO MAKE A FEW ADJUSTMENTS TO THE ONGOING TAFS OVERNIGHT. A COLD
FRONT WILL MOVE THROUGH THIS AFTERNOON/EVENING...AND SOME CONVECTION
IS EXPECTED ALONG THE FRONT. HAVE THE HIGHEST CONFIDENCE OF
CONVECTION AT SAW...SO INCLUDED VCSH THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 PM EDT TUE SEP 10 2013
PATCHY TO AREAS OF FOG SHOULD SLOWLY DISSIPATE INTO THIS EVENING AS
DRIER AIR WORKS IN FROM THE NORTH. WEAK HIGH PRESSURE THIS EVENING
WILL BE REPLACED BY A BROAD TROUGH THAT WILL BE EXTENDING SOUTHWARD
FROM NORTHERN ONTARIO LATE TONIGHT THROUGH EARLY WEDNESDAY EVENING.
A LARGE HIGH PRESSURE ENCOMPASSING MUCH OF S CENTRAL CANADA AND THE
N PLAINS WEDNESDAY NIGHT WILL SLOWLY DRIFT ACROSS THE UPPER GREAT
LAKES FRIDAY INTO SATURDAY...BEFORE EXITING TO THE LOWER GREAT LAKES
AND THE E COAST FOR THE LATTER HALF OF THE WEEKEND. THE STRONGEST
WINDS OVER LAKE SUPERIOR...OUTSIDE OF THUNDERSTORMS...WILL BE LATE
WEDNESDAY NIGHT THROUGH EARLY FRIDAY MORNING...WITH N GUSTS OF
20-30KTS CENTERED ACROSS MAINLY CENTRAL AND E LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JT/KF
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1251 AM CDT WED SEP 11 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 317 PM CDT TUE SEP 10 2013
MORNING MAP ANALYSIS INDICATES A CLOSED MID LEVEL LOW OVER THE
SOUTHWESTERN CONUS...WITH RIDGING OVER THE EAST. A MID LEVEL
SHORTWAVE IS ALSO NOTED OVER SOUTH CENTRAL CANADA AND MOVING EAST.
THE PRIMARY AXIS OF MID TO UPPER LEVEL JET ENERGY EXTENDS FROM
WESTERN CANADA...SOUTHEAST INTO THE NORTHERN PLAINS...AND THEN
EAST/NORTHEAST INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW
IS FAIRLY WEAK OVER OUR AREA AS A RESULT...ONLY MAXING OUT AT
AROUND 30KTS AT VARIOUS POINT BETWEEN 500MB AND 200MB PER 12Z
SOUNDING DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY ALSO SHOWS
THE AFOREMENTIONED MID LEVEL LOW OVER THE SOUTHWESTERN CONUS...AS
WELL AS THE MID LEVEL SHORTWAVE OVER SOUTH CENTRAL CANADA. THE MID
LEVEL LOW OVER THE SOUTHWESTERN CONUS IS HELPING PULL MID LEVEL
MOISTURE NORTHWARD FROM MEXICO AND AS A RESULT...INCREASED VALUES
OF MID LEVEL MOISTURE ARE NOTED EXTENDING FROM THE SOUTHWESTERN
CONUS...NORTHEAST INTO THE ROCKY MOUNTAIN RANGE AND INTO PORTIONS
OF THE NORTHERN AND CENTRAL PLAINS. AT THE SURFACE A NEARLY
STATIONARY BOUNDARY IS NOTED EXTENDING FROM WESTERN KANSAS INTO
EASTERN NEBRASKA AND WESTERN IOWA. THIS BOUNDARY BISECTS OUR CWA
AND AS A RESULT...THE LOW LEVEL WIND FIELD ACROSS THE NORTHWESTERN
HALF OF OUR CWA REMAINS FROM THE NORTHEAST...WHILE LOCATIONS
FARTHER SOUTHEAST CONTINUE TO OBSERVE A SOUTHWESTERLY LOW LEVEL
WIND FIELD.
TO THE SOUTH OF THE LOW LEVEL BAROCLINIC ZONE...AFTERNOON SURFACE
TEMPERATURES HAVE CLIMBED WELL INTO THE 90S...WITH PROXIMITY
SOUNDINGS FROM LAPS AND RAP ANALYSIS INDICATING CONVECTIVE
TEMPERATURES HAVE BEEN REACHED. KUEX INDICATES ISOLATED SHOWER AND
THUNDERSTORM ACTIVITY DEVELOPING FROM WESTERN KANSAS INTO NORTH
CENTRAL KANSAS...INCLUDING SOUTHERN PORTIONS OF OUR CWA. THESE
SAME PROXIMITY SOUNDINGS SUGGEST ~1000J/KG OF POTENTIAL ENERGY IS
READY FOR UPDRAFT PRODUCTION...BUT VERY LITTLE IN THE WAY OF DEEP
LAYER BULK SHEAR IS PRESENT...PERHAPS NO HIGHER THAN 15 OR 20KTS.
GIVEN ALL THIS...ISOLATED SHOWER AND THUNDERSTORM ACTIVITY WILL
LIKELY PERSIST ACROSS SOUTHEASTERN PORTIONS OF OUR CWA THROUGH THE
REST OF THIS AFTERNOON. MULTIPLE SETS OF GUIDANCE SUGGEST LOW
LEVEL CONVERGENCE AND RESULTANT FORCING ALONG THE LOW LEVEL
BAROCLINIC ZONE MAY ALSO PROMOTE ISOLATED TO SCATTERED SHOWER AND
THUNDERSTORM CONVECTION ACROSS THE AREA. AS A RESULT...KEPT THE
~20% POP GOING ACROSS MUCH OF THE CWA 21-00Z.
ANY SURFACE-BASED CONVECTION THAT CAN BE REALIZED THIS AFTERNOON
AND/OR EVENING ACROSS OUR SOUTHERN COUNTIES...OR FARTHER NORTH
ALONG THE LOW LEVEL BAROCLINIC ZONE...SHOULD DISSIPATE SHORTLY
AFTER SUNSET AS DIABATIC HEATING IS LOST. THAT BEING
SAID...GUIDANCE SUGGESTS THE MID LEVEL SHORTWAVE...CURRENTLY OVER
SOUTH CENTRAL CANADA...WILL MOVE SOUTHEAST THUS PUSHING THE MID
LEVEL JET AXIS FARTHER SOUTH AS WELL. THIS WILL IN TURN PUSH A
30-40KT MID LEVEL JET STREAK FARTHER SOUTH INTO THE UPPER
MISSISSIPPI VALLEY AND PORTIONS OF THE NORTHERN PLAINS...WITH THE
RIGHT-REAR QUADRANT OF THIS JET STREAK SETTING UP OVER NORTHERN
PORTIONS OF OUR CWA. IT APPEARS AS THOUGH THERE WILL BE ENOUGH OF
A THERMALLY-DIRECT CIRCULATION AND RESULTANT OMEGA FOR ADDITIONAL
SHOWER AND THUNDERSTORM DEVELOPMENT...PRIMARILY ACROSS OUR
NORTH...OVERNIGHT TONIGHT AND AS A RESULT...~30% POPS HAVE BEEN
PLACED PRIMARILY ACROSS THE NORTHERN HALF OF OUR CWA 00-12Z
WEDNESDAY.
THERE MAY BE SOME LINGERING SHOWER AND THUNDERSTORM ACTIVITY EARLY
WEDNESDAY MORNING...BUT GUIDANCE SUGGESTS THIS ACTIVITY SHOULD
DISSIPATE BY AROUND SUNRISE. DRY CONDITIONS WILL MORE THAN LIKELY
BE OBSERVED THROUGH MUCH OF THE DAY WEDNESDAY...HOWEVER THE LOW
LEVEL BAROCLINIC ZONE...CURRENTLY OVER CENTRAL PORTIONS OF OUR
CWA...IS ONLY EXPECTED TO SHIFT SLIGHTLY SOUTH TONIGHT AND BY
WEDNESDAY AFTERNOON IS EXPECTED TO STRETCH ACROSS THE SOUTHEASTERN
ONE-THIRD OF OUR CWA. LOW LEVEL CONVERGENCE AND RESULTANT FORCING
ALONG THE LOW LEVEL BAROCLINIC ZONE MAY PROMOTE ANOTHER ROUND OF
AFTERNOON SHOWER AND THUNDERSTORM ACTIVITY ON WEDNESDAY AND AS A
RESULT...20-30% POPS HAVE BEEN PLACED ACROSS PORTIONS OF THE CWA
FOR WEDNESDAY AFTERNOON AND EVENING...WITH THE HIGHEST POPS
RELEGATED TO OUR SOUTHEAST IN CLOSEST PROXIMITY TO THE LOW LEVEL
BAROCLINIC ZONE.
GUIDANCE SUGGESTS POTENTIAL ENERGY WILL NOT CLIMB MUCH HIGHER THAN
1000J/KG THIS AFTERNOON AND EVENING...AND WITH LITTLE IN THE WAY
OF DEEP LAYER BULK SHEAR...THE THREAT FOR SEVERE WEATHER SEEMS
FAIRLY LIMITED. THAT BEING SAID...THERE IS A CHANCE UPDRAFT
STRENGTH COULD BE STRONG ENOUGH TO PROMOTE SOME HAIL...CURRENTLY
EXPECTED TO REMAIN SUB-SEVERE...AND SO WILL OUTLOOK THIS IN THE
HWO. IN ADDITION...FORECAST PROXIMITY SOUNDINGS SUGGEST FAIRLY
DEEP INVERTED-V SOUNDINGS...TO BETWEEN 800MB AND 750MB...COULD
ALSO PROMOTE A WIND GUST THREAT. WILL GO AHEAD AND OUTLOOK BRIEF
WIND GUSTS TO AROUND 50 MPH IN THE HWO FOR THIS AFTERNOON AND
EVENING AS WELL. TROPOSPHERIC CONDITIONS...FOR LOCATIONS NEAR AND
AHEAD OF THE LOW LEVEL BAROCLINIC ZONE...APPEAR AS THOUGH THEY
WILL BE SIMILAR ON WEDNESDAY WHEN COMPARED TO TODAY AND AS A
RESULT...WILL GO AHEAD AND OUTLOOK THE THREAT FOR SUB-SEVERE HAIL
AND WIND GUSTS...PRIMARILY ACROSS OUR SOUTH...FOR WEDNESDAY
AFTERNOON AND EVENING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 317 PM CDT TUE SEP 10 2013
WEDNESDAY NIGHT...THE SFC COOL FRONT WILL REMAIN WELL TO THE SOUTH
OF OUR FORECAST AREA AND WILL LIKELY BE LOCATED OVER OKLAHOMA. AN
UPPER LEVEL TROUGH WILL BE SCOOTING TO OUR NORTHEAST AND THE BEST
CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ASSOCIATED WITH AN
OVERRUNNING SET UP ACROSS KANSAS. NEBRASKA WILL BE SO FAR NORTH OF
THE FRONT WITH DRIER AIR STARTING TO WORK IN AND HENCE LESSER POPS
AS YOU HEAD NORTH THROUGH OUR NEBRASKA ZONES.
THURSDAY AND FRIDAY...A SFC HIGH WILL SLIDE INTO THE GREAT LAKES
RESULTING IN A WIND SHIFT AS WE BEGIN TO GET MORE OF AN EASTERLY
UPSLOPE FLOW ON THURSDAY AND THEN A RETURN SOUTHEASTERLY STILL
SOMEWHAT UPSLOPE FLOW ON FRIDAY. THIS WILL RESULT IN THUNDERSTORM
CHANCES ACROSS THE HIGH PLAINS AND THEN SLIGHT CHANCES OF SHOWERS
AND THUNDERSTORMS ACROSS OUR FAR SOUTHWESTERN COUNTIES AS WESTERN
THUNDERSTORMS TRY TO MAKE IT EAST...BUT WILL LIKELY STRUGGLE. THE
TRI CITIES AND POINTS NORTH AND EAST ARE LIKELY GOING TO BE DRY
DURING THIS PERIOD. TEMPERATURES SHOULD BE BELOW NORMAL FOR THE
FIRST TIME SINCE AROUND THE MIDDLE OF AUGUST...WHICH WAS THE LAST
TIME WE SAW HIGHS ONLY IN THE 70S. ALTHOUGH BOTH THURSDAY AND
FRIDAY WILL BE COOL IN THE 70S FOR HIGHS...FRIDAY WILL BE THE
COOLEST OF THE TWO DAYS WITH HIGHS ONLY IN THE LOWER TO MID 70S.
WEEKEND...THE COOL WEATHER WILL PERSIST WITH CLOUDS AND SEVERAL
CHANCES OF SHOWERS AND THUNDERSTORMS AS WEAK PIECES OF A SHORTWAVE
TROUGH TRACK THROUGH THE CENTRAL PLAINS. PRECIPITATION CHANCES
SEEM FAIR GENERALLY IN THE 30 TO 40 PERCENT RANGE. THESE CHANCES
MAY BE RAISED IN COMING DAYS IF CURRENT WET LOOKING MODEL TRENDS
CONTINUE. HIGHS SHOULD CONTINUE TO BE IN THE 70S ACROSS NEBRASKA
TO NEAR 80 IN KANSAS. HOWEVER...COULD SEE THESE HIGHS BEING
LOWERED...PARTICULARLY ON SUNDAY...IF RAIN CHANCES INCREASE DUE TO
CLOUDS AND COOLER EAST NORTHEASTERLY FLOW. CONSEQUENTLY...THIS IS
A HEADS UP THAT OUR FORECAST HIGHS ARE CURRENTLY ON THE WARMER END
OF THE MODEL GUIDANCE...SO DO NOT BE SURPRISED IF HIGHS ARE
LOWERED WITH FUTURE FORECAST UPDATES.
MONDAY AND TUESDAY...CONFIDENCE IS LOW WITH SOME MODELS INDICATING
CONTINUED SHORT WAVES AND THUNDERSTORM CHANCES WHILE OTHER
FORECAST MODELS DRY OUT. POPS WILL BE LOW DUE TO UNCERTAINTY.
TEMPERATURES SHOULD BE SOMEWHAT NEAR NORMAL AND WILL BE CALLING
FOR HIGHS IN THE UPPER 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1247 AM CDT WED SEP 11 2013
MAIN STORY THROUGH THIS TAF PERIOD LIES WITH THE CONTINUED
PRESENCE OF THE SFC FRONTAL BOUNDARY...AND CHANCES FOR
PRECIPITATION. THE REST OF TONIGHT...CLOUDS EXPECTED TO REMAIN IN
THE MID/UPPER LEVELS...AND CANT COMPLETELY RULE OUT SOME SHOWER
ACTIVITY SO WILL CARRY A VCSH MENTION. SHOULD SEE DRY CONDITION
THROUGH MOST OF THE DAYTIME HOURS...BUT WITH THE SFC FRONT
REMAINING IN THE AREA AND ANY ADDITIONAL DISTURBANCES...THE
POTENTIAL FOR SOME SCATTERED PRECIP WILL RETURN...SO INSERTED
ANOTHER VC MENTION FOR THE AFTERNOON/EVENING HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...WESELY
AVIATION...ADO
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1143 PM CDT TUE SEP 10 2013
.AVIATION...
ISOLD SHRA POSSIBLE OVERNIGHT. ISOLD TO SCT SHRA/TSRA EXPECTED
WEDNESDAY WITH GREATEST COVERAGE OVER THE RIO GRANDE. HAVE
MENTIONED TEMPO -RA FOR KDRT OVERNIGHT INTO EARLY WEDNESDAY.
OTHERWISE...NO MENTION IN TAFS DUE TO LOW PROBABILITY. VFR SKIES
LATE EVENING LOWER TO MVFR/IFR CIGS/VSBYS OVERNIGHT INTO EARLY
WEDNESDAY MORNING. DUE TO MOIST AIRMASS...PATCHY FG WITH VLIFR
VSBYS IS POSSIBLE. CIGS LIFT TO VFR AND BR/FG DISSIPATE BY MIDDAY.
E TO SE WINDS 7 TO 12 KTS DECREASE TO LESS THAN 6 KTS OVERNIGHT
AND THEN INCREASE TO 7 TO 12 KTS LATE WEDNESDAY AFTERNOON.
DOWNDRAFT WIND GUSTS TO 35 KTS ARE POSSIBLE IN AND NEAR SHRA/TSRA.
&&
.PREV DISCUSSION... /ISSUED 854 PM CDT TUE SEP 10 2013/
UPDATE...
A DOWNWARD TREND TO WHAT HAS OCCURRED THE PAST FEW EVENINGS IS
EXPECTED TO CONTINUE INTO LATE TONIGHT...WITH LIGHT STREAMER
SHOWERS EXPECTED TO REDEVELOP IN THE OVERNIGHT HOURS INTO
DAYBREAK. THIS IS REINFORCED BY THE RECENT RUC AND HRRR RUNS. WILL
DROP CHANCES TO 20 PERCENT OR LESS AND REMOVE THUNDER FOR ALL BUT
THE SOUTHEAST COUNTIES AROUND DAYBREAK. A FEW LIGHTNING STRIKES
MAY DEVELOP THIS EVENING NEAR THE RIO GRANDE...BUT EXPECT THEM TO
BE ACROSS THE BORDER WHERE TERRAIN FEATURES WILL CONTRIBUTE TO
CELL GROWTH.
PREV DISCUSSION... /ISSUED 646 PM CDT TUE SEP 10 2013/
AVIATION...
ISOLD SHRA/TSRA SLOWLY END THIS EVENING...HOWEVER LINGERS OVER THE
RIO GRANDE OVERNIGHT. ISOLD TO SCT SHRA/TSRA EXPECTED WEDNESDAY
WITH GREATEST COVERAGE OVER THE RIO GRANDE. HAVE MENTIONED TEMPO
-RA FOR KDRT OVERNIGHT INTO EARLY WEDNESDAY. OTHERWISE...NO
MENTION IN TAFS DUE TO LOW PROBABILITY. VFR SKIES THIS EVENING
LOWER TO MVFR/IFR CIGS/VSBYS OVERNIGHT INTO EARLY WEDNESDAY
MORNING. DUE TO MOIST AIRMASS...PATCHY FG WITH VLIFR VSBYS IS
POSSIBLE. CIGS LIFT TO VFR AND BR/FG DISSIPATE BY MIDDAY. E TO SE
WINDS 7 TO 12 KTS DECREASE TO LESS THAN 6 KTS OVERNIGHT AND THEN
INCREASE TO 7 TO 12 KTS LATE WEDNESDAY AFTERNOON. DOWNDRAFT WIND
GUSTS TO 35 KTS ARE POSSIBLE IN AND NEAR SHRA/TSRA.
PREV DISCUSSION... /ISSUED 302 PM CDT TUE SEP 10 2013/
SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)...
THIS AFTERNOON SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE
OCCURRING ACROSS MUCH OF SOUTH CENTRAL TEXAS AS DAYTIME HEATING
INTERACTED WITH THE TROPICAL AIRMASS. THE AWIPS TOTAL BLENDED PWAT
PRODUCT STILL DEPICTED VALUES RANGING FROM 1.8 INCHES NORTH TO 2.0
INCHES SOUTH. THESE VALUES ARE ASSOCIATED WITH LOCALLY HEAVY
RAINFALL. THE CONVECTION WILL DIMINISH IN AREA COVERAGE OVERNIGHT
WITH THE LOSS OF HEATING. HOWEVER ISOLATED SHOWERS AND THUNDERSTORMS
WILL CONTINUE OVER THE RIO GRANDE PLAINS AFTER MIDNIGHT WHERE
DEEP TROPICAL MOISTURE WILL PERSIST. LOWS WILL BE SLIGHTLY ABOVE
SEASONAL NORMALS. AN UPPER LEVEL RIDGE OVER THE OHIO VALLEY WILL
BUILD TO THE SOUTHWEST INTO TEXAS ON WEDNESDAY KEEPING THE DEEPER
MOISTURE AXIS WEST OVER THE RIO GRANDE PLAINS. THUS CONVECTIVE
COVERAGE ON WEDNESDAY WILL RANGE FROM ISOLATED NORTHEAST TO
SCATTERED WEST. CLOUDS AND PCPN WILL KEEP AFTERNOON HIGHS AROUND
NORMAL ON WEDNESDAY. SHOWERS AND THUNDERSTORMS WILL END BY
MIDNIGHT WITH LOWS WEDNESDAY NIGHT SIMILAR TO WHAT IS EXPECTED
TONIGHT.
LONG TERM (THURSDAY THROUGH TUESDAY)...
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL OCCUR GENERALLY
ALONG AND SOUTH OF HIGHWAY 90 ON THURSDAY AS THE EASTERLIES ENHANCE
CONVECTION ON THE SEA-BREEZE BOUNDARY. FRIDAY IS EXPECTED TO BE DRY
AS THE UPPER HIGH BRIEFLY BECOMES CENTERED OVER NORTH TEXAS. ALL
EYES WILL BE ON THE GULF OF MEXICO AND THE BAY OF CAMPECHE OVER
THE WEEKEND. A TROF OF LOW PRESSURE CURRENTLY LOCATED OVER THE
CARIBBEAN NEAR BELIZE WILL MOVE WESTWARD INTO THE BAY OF CAMPECHE
BY THURSDAY. A TROPICAL DEPRESSION IS EXPECTED TO FORM OVER THE
SOUTHWESTERN GULF LATER THIS WEEK AND HAS A HIGH CHANCE OF BECOMING
A TROPICAL CYCLONE OVER THE WEEKEND. THE TRACK OF THIS SYSTEM WILL
HAVE A DIRECT IMPACT ON THE FORECAST FOR SOUTH CENTRAL TEXAS. ATTM
THE MODEL CONSENSUS IS FOR THE SYSTEM TO MOVE WESTWARD MAKING LANDFALL
IN MEXICO ON MONDAY NEAR TAMPICO. THE 12Z GFS IS THE FURTHEST NORTH
WITH THE TRACK...MOVING ONSHORE SOUTH OF BROWNSVILLE...THEN MOVING
NORTHWEST UP THE RIO GRANDE. IN ANY EVENT INCREASING TROPICAL MOISTURE
WITH THIS SYSTEM WILL LEAD TO INCREASING POPS WITH THE POTENTIAL
FOR HEAVY RAINFALL ACROSS SOUTH CENTRAL TEXAS EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 74 95 74 95 74 / 10 10 - 10 -
AUSTIN BERGSTROM INTL AIRPORT 70 94 70 94 70 / 10 10 10 10 -
NEW BRAUNFELS MUNI AIRPORT 70 94 70 94 69 / 10 20 10 20 -
BURNET MUNI AIRPORT 70 92 71 93 71 / 10 10 - 10 -
DEL RIO INTL AIRPORT 75 90 73 92 73 / 20 30 10 20 -
GEORGETOWN MUNI AIRPORT 71 94 71 94 72 / 10 10 - 10 -
HONDO MUNI AIRPORT 73 93 72 93 71 / 20 20 10 10 -
SAN MARCOS MUNI AIRPORT 70 95 71 95 70 / 10 10 10 10 -
LA GRANGE - FAYETTE REGIONAL 75 95 75 95 75 / 10 20 10 10 10
SAN ANTONIO INTL AIRPORT 75 94 75 93 74 / 20 20 10 10 -
STINSON MUNI AIRPORT 76 94 76 94 75 / 20 20 10 20 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...04
SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1138 PM CDT TUE SEP 10 2013
.UPDATE...
ISSUED AT 639 PM CDT TUE SEP 10 2013
LOW TO MID LEVEL FRONTOGENESIS BEGINNING TO GET GOING FROM CENTRAL
IOWA INTO CENTRAL WISCONSIN...NOTED BY ISOLATED SHOWERS THAT HAVE
DEVELOPED. SO FAR ALL LIGHTNING ACTIVITY HAS STAYED DOWN TOWARDS
CENTRAL IOWA. HOWEVER...RAP/NAM/ECMWF SOUNDINGS ALL SHOW ELEVATED
INSTABILITY ON THE ORDER OF 250-750 J/KG LIFTED FROM 850MB. AS THE
FRONTOGENESIS STRENGTHENS PER MODEL PROGS THIS EVENING...
ANTICIPATING THAT SOME OF THE SHOWER ACTIVITY WILL TAKE ADVANTAGE
OF THIS INSTABILITY AND PRODUCE LIGHTNING. HRRR MODEL FORECASTS
SUGGEST THIS AS WELL. THEREFORE...HAVE ADDED ISOLATED- SCATTERED
THUNDERSTORMS BACK INTO THE FORECAST...MAINLY SOUTH OF INTERSTATE
90 WHERE THE ELEVATED INSTABILITY IS PROGGED. ADDITIONALLY...IT IS
POSSIBLE PRECIPITATION CHANCES WILL NEED TO BE RAISED ACROSS
PORTIONS OF THIS AREA WITH ADDED THUNDER. ECMWF/NAM/HRRR FORECASTS
THIS EVENING REALLY INCREASE PRECIPITATION COVERAGE. WILL MONITOR
TRENDS IN RADAR DATA TO SEE IF THE MODELS ARE HANDLING
PRECIPITATION OKAY. SO FAR THEY SEEM TO BE.
&&
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 244 PM CDT TUE SEP 10 2013
SURFACE MAP HAS LOW PRESSURE OVER LAKE SUPERIOR WITH A COLD FRONT
EXTENDING THROUGH CENTRAL UPPER MI TO JUST NORTH OF LA CROSSE...AND
THEN THROUGH NORTHERN IA. RADAR MOSAIC WAS SHOWING A SCATTERED BAND
OF POST-FRONTAL SHOWERS ACROSS WESTERN UPPER MI THROUGH NORTH
CENTRAL WI INTO SOUTHERN MN. NOT MUCH OF THIS REFLECTIVITY WAS BEING
REALIZED AT THE SURFACE...AND WHERE IT WAS...RAINFALL WAS SCANT WITH
GENERALLY .02 INCH OR LESS. PER THE RAP MODEL...THIS BAND OF SHOWERS
WAS TIED TO SOME 850-700MB FRONTOGENESIS BEHIND THE SURFACE FRONT.
OTHERWISE...TEMPERATURES ACROSS THE AREA RANGED FROM NEAR 80 ACROSS
NORTH CENTRAL WI...TO A FEW LOWER 90S ACROSS NORTHEAST IA INTO
SOUTHWEST WI.
SO...MAIN FORECAST CHALLENGE WILL BE RAIN CHANCES TONIGHT INTO
WEDNESDAY WITH THE PASSAGE OF THIS FRONT AND POST-FRONTAL FORCING.
LOOK FOR THE THE MAIN SURFACE FRONT TO CONTINUE PUSHING SOUTHEAST
THROUGH THE AREA TONIGHT WHILE 850-700MB FRONTOGENESIS LAGS BEHIND.
RAP SHOWING 850-700MB FG-FORCING...ALBEIT NOT OVERLY
STRONG...MAINTAINING ITSELF AS IT DRIFTS SOUTHEAST ACROSS THE AREA
THIS EVENING/OVERNIGHT. THE NAM ACTUALLY SHOWS THIS FORCING
INTENSIFYING A BIT...BUT MORE ACROSS EAST CENTRAL WI. BASED ON WHAT
IS HAPPENING NOW AND FORECAST FORCING SIGNAL...HAVE DOWNPLAYED
RAIN CHANCES AND DROPPED THUNDER MENTION AS FORCING AND CAPE WANE.
PLAN ON OVERNIGHT LOW TEMPERATURES IN THE UPPER 50S TO THE MIDDLE
60S.
FOR WEDNESDAY...WILL BE WATCHING THE COLD FRONTAL BOUNDARY CONTINUE
TO SLIP SOUTH OF OUR AREA WITH 850-700MB FG-FORCING ALMOST
NON-EXISTENT. AS SUCH...PUSHED ANY REMAINING SHOWER CHANCES SOUTH OF
THE FORECAST AREA BY AFTERNOON. OTHERWISE...LOOKING AT A MID-LEVEL
TROUGH/REINFORCING SHOT OF COOLER AIR DROPPING INT NORTHERN WI BY
LATE IN THE AFTERNOON. MODELS ARE PRODUCING SOME SHRA/ISOLATED
THUNDER WITH THIS WAVE...BUT KEEPING IT NORTH OF THE FORECAST AREA.
OTHERWISE...LOOK FOR HIGHS ACROSS THE FORECAST AREA IN THE 80-85
DEGREE RANGE.
COOLER/DRIER AIR FILTERS IN FOR WEDNESDAY NIGHT AS HIGH PRESSURE
BUILDS INTO THE UPPER MISSISSIPPI RIVER REGION FROM THE CENTRAL
CANADIAN PROVINCES. LOOK FOR OVERNIGHT LOWS IN THE 50-60 DEGREE
RANGE WITH NORTHWEST WINDS OF 5-10 MPH.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 244 PM CDT TUE SEP 10 2013
CONTINUED DRY/COOL FLOW CONTINUES INTO THE AREA ON THURSDAY AS HIGH
PRESSURE BUILDS IN ACROSS THE NORTHERN PLAINS/MN. FAIRLY STEEP LAPSE
RATES WILL BE IN PLACE WITH 925MB TEMPERATURES IN THE 10-17C RANGE
AND 500MB IN THE -5 TO -15C RANGE. THIS IS EXPECTED TO PRODUCE A
PRETTY GOOD FIELD OF CUMULUS/STRATOCUMULUS...ESPECIALLY AREAS
NORTHEAST OF I-94. ANY SHOWER THREAT LOOKS TO STAY NORTH OF THE
AREA.
HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER PICTURE THURSDAY
NIGHT THROUGH SATURDAY. THURSDAY NIGHT AND ESPECIALLY FRIDAY NIGHT
WILL SET UP FAVORABLE RIVER VALLEY FOG CONDITIONS WITH CLEAR SKIES
AND LIGHT/CALM WINDS. RATHER CHILLY OVERNIGHT LOWS ARE ALSO EXPECTED
THURSDAY NIGHT AND FRIDAY NIGHT WITH PLANNED FORECAST LOWS
DROPPING INTO UPPER 30S IN THE FAVORED COLD SPOTS ALONG AND
NORTHEAST OF I-94. WILL HAVE TO WATCH CLOSELY FOR THE POTENTIAL OF
PATCHY FROST ACROSS THIS AREA THURSDAY NIGHT AS THE COLDEST CORE OF
AIR ALOFT SINKS ACROSS THE REGION.
WILL BE WATCHING THE HIGH DRIFT EAST OF THE AREA SATURDAY NIGHT
INTO SUNDAY AS A FAIRLY VIGOROUS //AT LEAST ACCORDING TO THE
ECMWF// MID-LEVEL TROUGH AND SURFACE COLD FRONT DROPS SOUTHEAST
INTO THE AREA. THE GFS IS NOT AS ENTHUSED AS THE ECMWF. NEW 12Z
ECMWF LOOKING MORE LIKE THE GFS NOW....KEEPING POPS SPLIT TO THE
NORTH AND SOUTH OF THE AREA. LOWERED POPS FOR NOW...BUT IF TREND
CONTINUES...COULD PROBABLY DROP POPS ALTOGETHER FOR THE AREA. WILL
KEEP AN EYE ON THIS.
A STRONG AREA OF CANADIAN HIGH PRESSURE BUILDS INTO THE AREA FOR
SUNDAY NIGHT AND HOLDS AT LEAST THROUGH MONDAY NIGHT. THIS IS
EXPECTED TO YIELD DRY CONDITIONS WITH SLIGHTLY BELOW NORMAL
TEMPERATURES THROUGH THE PERIOD. LOOK FOR OVERNIGHT LOWS IN THE
UPPER 40S TO THE LOWER 50S WITH HIGHS IN THE MIDDLE 60S TO AROUND
THE 70 DEGREE MARK.
THE ECMWF AND GFS THEN DIFFER A BIT WITH SPEED OF A SHORTWAVE TROUGH
PUSHING EAST OUT OF THE PLAINS ON TUESDAY. THE ECMWF IS THE FASTER
OF THE TWO...SPREADING SHOWER/THUNDERSTORM CHANCES IN DURING THE
DAY. THE GFS IS MUCH SLOW AND MAINTAINS RIDGING ACROSS THE AREA.
WILL KEEP A DRY/COOL FORECAST GOING FOR NOW AND WAIT FOR BETTER
MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1138 PM CDT TUE SEP 10 2013
WEST TO NORTHWEST WINDS WILL CONTINUE TO ADVECT DRIER AIR IN THE
LOWER LEVELS OF THE ATMOSPHERE INTO THE TAF SITES THROUGH
WEDNESDAY NIGHT. THIS DRIER AIR WILL HELP TO MAINTAIN VFR
CONDITIONS. DAYTIME MIXING AND A RELATIVELY TIGHT PRESSURE
GRADIENT MAY ALLOW WINDS TO GUST TO 15 KT OR SO AT LSE...WITH
BOTH LSE AND RST LIKELY TO SEE WINDS SUSTAINED AROUND 10 KT. WINDS
AND GUSTS WILL SUBSIDE QUICKLY WITH LOSS OF DAYTIME HEATING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...AJ
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS PUEBLO CO
936 AM MDT WED SEP 11 2013
.UPDATE...
ISSUED AT 925 AM MDT WED SEP 11 2013
FIRST BATCH OF LIGHT TO MODERATE SHOWERS OVER THE WALDO CANYON
BURN SCAR HAS FILLED STREAMS TO NEAR BANK FULL WITH SOME MINOR
FLOODING. WITH CONTINUED MOIST SOUTHERLY FLOW..DECIDED TO ISSUE A
FLASH FLOOD WATCH FOR THE WALDO CANYON AND BLACK FOREST BURN SCARS
AS ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AND
THIS EVENING.
RADAR SHOWS ONE SMALL ROTATION NEAR PUEBLO WEST. CONVECTION IS
DEVELOPING IN CENTRAL NEW MEXICO IN THE DRY SLOT...AND THIS
CONVECTION IS MOVING NORTH. SOME SHORT RANGE MODELS SUGGEST THESE
DISTURBANCES WILL BE STRONG ENOUGH DEVELOP SOME CONVECTION DURING
THE DAY. WALDO CANYON...IN PARTICULAR...APPEARS TO BE PRIMED FOR
SOME FLASH FLOODING IF HEAVIER RAIN PASSES OVER THE BURN SCAR.
--PGW--
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM MDT WED SEP 11 2013
THE UPR LOW IS EXPECTED TO BE CENTERED OVR THE SWRN CORNER OF UT
TODAY AND MAYBE MOVING SLIGHTLY NORTHWARD OVERNIGHT. MODELS ARE
SHOWING THE PLUME OF UPR MSTR SHIFTING EASTWARD THRU THE DAY AND
MAINLY BEING OVR THE EASTERN PORTIONS OF THE FORECAST AREA THIS
AFTERNOON...AND THEN BEING OVR THE FAR SERN PLAINS TONIGHT. WV
IMAGERY THIS MORNING SHOWING THE DRIER AIR WORKING ITS WAY INTO SWRN
CO. CURRENT RADAR LOOP SHOWING SOME ISOLD TO SCT ECHOES OVR THE SAN
LUIS VALLEY AND ALONG THE CONTDVD...WITH MORE PCPN OVR ERN AREAS AND
ADDITIONAL PCPN WORKING ITS WAY NORTHWARD FROM EASTERN NM.
IN GENERAL...THE HRRR SHOWS MAINLY ISOLD TO SCT POPS OVR THE SAN
LUIS VALLEY AND ALONG THE CONTDVD TODAY...WITH SCT OR HIGHER POPS
FROM THE ERN MTS TO THE ERN BORDER. THE WRF IS SIMILAR...ALTHOUGH IT
SHOWS HIGHER POPS OVR THE HIGHER TRRN IN THE MORNING HOURS...AND
THEN DECREASES THE PCPN CHANCES FOR THE AFTERNOON HOURS ALONG THE
CONTDVD AND SAN LUIS VALLEY AS THE DRIER AIR MOVES SPREADS OVR THE
AREA. THE NAM LOOKS OVERDONE AGAIN IN TERMS OF PCPN ACCUMULATION OVR
THE ERN MTS AND I-25 CORRIDOR FOR THE MORNING HOURS. BASED ON THE
WRF AND HRRR...PCPN OVR THE BURN SCARS TODAY SHOULD MOSTLY BE HIT
OR MISS AND NOT A PROLONGED EVENT...WL NOT ISSUE A FLASH FLOODING
HIGHLIGHT. HOWEVER THERE IS STILL THE CHANCE FOR LOCALLY HEAVY
RAIN AND THE STEERING FLOW TODAY IS EXPECTED TO BE ONLY AROUND
10-15 KTS OVR THE ERN MTS AND I-25 CORRIDOR...THUS FLASH FLOODING
CANNOT BE RULED OUT IF A STRONG SLOW MOVING STORM WERE TO MOVE OVR
AREA BURN SCARS. TEMPS OVR THE MTN PEAKS WL AGAIN BE COLD ENOUGH
FOR SOME SNOW TO OCCUR WITH SOME LIGHT ACCUMULATIONS.
FOR TONIGHT...ALL MODELS BRING DRIER CONDITIONS TO THE WESTERN HALF
OF THE FORECAST AREA...WITH SOME PCPN CONTINUING THRU THE NIGHT OVR
PORTIONS OF THE ERN PLAINS...ESPECIALLY THE FAR EASTERN AREAS AS A
COUPLE DISTURBANCES MOVES ACRS THAT AREA.
|
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 333 AM MDT WED SEP 11 2013
...WET THROUGH SUNDAY...
...DRYING OUT NEXT WEEK...
WET FORECAST REMAINS ON TRACK. WETTEST PERIOD STILL LOOKS TO BE THU
INTO FRI OF THIS WEEK...WHEN THE UPPER LOW IS MOVING THROUGH WRN UT
AND ERN NV...AND UPSLOPE WILL BE MAXIMIZED OVER THE ERN CO PLAINS.
THE ERN MTS...IN PARTICULAR THE ERN SLOPES...WILL LIKELY SEE THE
MOST QPF FROM THIS EVENT. THE NAM12 IS STILL PROGGING 2-4 INCHES OF
LIQUID FOR THE SRN FRONT RANGE AND PIKES PEAK REGION. PRETTY MUCH
THE ENTIRE AREA SHOULD SEE AN INCH OF RAIN OR BETTER OVER THE NEXT
SEVERAL DAYS. THE EXCEPTIONS COULD BE THE SAN LUIS VALLEY AND
PORTIONS OF THE ARKANSAS CANYON...WHICH COULD BE SHELTERED SOMEWHAT
WITH THESE SPOTS NOT AS CONDUCIVE TO UPSLOPE PRECIP. PORTIONS OF THE
FAR ERN PLAINS MIGHT ALSO SEE A BIT MORE SPOTTY TOTALS...SINCE THE
PRECIP THERE WILL BE A BIT MORE DEPENDENT ON WHERE CONVECTION SETS
UP. THE HIGHEST AMTS SHOULD BE OVR THE SRN SANGRES...RATON
MESA...AND PALMER DVD AND PIKES PEAK AREA. BURN SCARS IN THIS AREA
WILL BE THE MAIN CONCERN THROUGH THE WEEKEND.
TEMPS SHOULD STAY ON THE COOL SIDE...IN THE 60S AND 70S...THRU
FRIDAY...THEN REBOUND A BIT ON SATURDAY BEFORE ANOTHER FRONT MOVES
THROUGH ON SUN AND KNOCKS THINGS DOWN BELOW AVG AGAIN. POPS WILL
ALSO INCREASE AGAIN ON SUNDAY AS THE NEXT FRONT ARRIVES. SNOW LEVELS
REMAIN RELATIVELY HIGH THROUGH THE END OF THE WEEK...BUT AS
MENTIONED PREVIOUSLY THE HIGHEST ELEVS ABOVE 13K FT OR SO WILL SEE
SOME ACCUMULATING SNOW...PERHAPS QUITE A BIT FOR THE HIGHEST SUMMITS.
BY THE WEEKEND...SNOW LEVELS SHOULD DROP TO AS LOW AS 12K FEET...AND
THIS COULD GIVE THE ERN MTS A GOOD SHOT OF SNOW BY THE END OF THE
WEEKEND.
NEXT WEEK...THE PATTERN WILL BE DOMINATED BY A PROGRESSIVE UPPER LOW
MOVING OUT OF THE PACNW TUE-WED...AND THEN QUICKLY THROUGH THE NRN
ROCKIES ON THU. MOST OF OUR AREA WILL BE TO THE SOUTH OF THE MAIN
CIRCULATION...SO THE PLAINS WILL LIKELY STAY MAINLY DRY AND PERHAPS
A BIT BREEZY. THE MTS COULD SEE SOME OROGRAPHIC PRECIP...BUT MAY SEE
MORE WIND THAN RAIN/SNOW UNLESS THE LOW TRACKS A BIT FARTHER S THAN
THE MODELS CURRENTLY INDICATE. TEMPS SHOULD ALSO CLIMB BACK TO ABOVE
AVG FOR THE PLAINS...POSSIBLY REACHING THE MID 80S OR HIGHER BY
WED-THU. ROSE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 333 AM MDT WED SEP 11 2013
PCPN IS WORKING ITS WAY NORTHWARD THIS MORNING AND SHOULD BRING
SHOWERS TO KCOS AND KPUB...WITH THE POTENTIAL FOR MVFR CONDITIONS
AND MAYBE EVEN SOME BRIEF IFR CONDITIONS AT KCOS. KALS WL ALSO
HAVE SOME LIGHT RAIN IN THE VCNTY THRU THE MORNING. THIS AFTERNOON
AND EVENING THE THREE TERMINAL SITE COULD HAVE TSTMS IN THE AREA.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR COZ081-084-085.
&&
$$
UPDATE...PGW
SHORT TERM...28
LONG TERM...ROSE
AVIATION...28
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1026 AM EDT WED SEP 11 2013
.SYNOPSIS...
VERY WARM AND HUMID CONDITIONS WILL BE IN PLACE ACROSS THE
REGION THROUGH THURSDAY. A COLD FRONT WILL BRING SHOWERS AND
THUNDERSTORMS WITH GUSTY WINDS AND HEAVY RAIN THURSDAY AND
THURSDAY NIGHT...POSSIBLY LINGERING INTO FRIDAY MORNING ACROSS
EASTERN MASSACHUSETTS. HIGH PRESSURE RETURNS FOR THE WEEKEND WITH
DRY AND MUCH COOLER WEATHER. A WEAK COLD FRONT WILL MOVE THROUGH
ON MONDAY. HIGH PRESSURE BRINGS DRY WEATHER AFTERWARD.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
*** EXCESSIVE HEAT AND HUMIDITY ***
*** A FEW STRONG STORMS POSSIBLE ***
ONLY CHANGE TO THE FORECAST WAS TO INTRODUCE THE CHANCE OF A FEW
STRONG STORMS LATE TODAY/THIS EVENING ACROSS WESTERN CT/MA AND
INTO SOUTHWEST NH. THIS LINES UP WELL WITH SPC LATEST SEVERE
WEATHER DAY1 OUTLOOK.
591 DAM MID LEVEL RIDGE PROVIDING A STRONG CAP/LID OVER THE
REGION THIS MORNING WITH LARGE SBCIN VALUES ACROSS SOUTHERN NEW
ENGLAND. HOWEVER WEAK HEIGHT FALLS LATER TODAY INTO THIS EVENING
ALONG WITH MID LEVEL FLOW BECOMING WEAKLY CYCLONIC WILL LIKELY
ERODE THIS CAP AND UNLEASH THE 2500-3500 J/KG OF CAPE THAT BUILDS
UP TODAY UNDER THE RIDGE.
GREATEST PROBABILITY FOR STORMS WILL BE OVER THE HIGHER TERRAIN OF
WESTERN CT/MA AND SOUTHWEST NH WHERE ELEVATED HEATING WILL
INCREASE THE RISK OF ERODING THE CAP. ALSO THIS AREA IS COLOCATED
WITH THE STRONGER DEEP LAYER SHEAR /ALBEIT MARGINAL/. IN ADDITION
REMNANT EML IS OVER THE AREA WITH MID LEVEL LAPSE RATES ON THE
ORDER OF 7-8C/KM. THIS WILL ENHANCE UPDRAFT POTENTIAL AND
CORRESPONDING STRONG DOWNDRAFTS/WIND THREAT.
FORECAST CONFIDENCE HAS INCREASED SOMEWHAT ON THIS SCENARIO AS
LAST FEW RUNS OF THE HRRR ALONG WITH 00Z ECMWF SIMULATE STORM
GENERATION OVER THE CATSKILLS AND POCONOS THIS AFTERNOON AND
TRAVERSE EASTWARD INTO WESTERN NEW ENGLAND THIS EVENING.
TIMING LOOKS TO BE AFTER 6 PM WESTERN CT/MA AND SOUTHWEST NH.
FARTHER EAST ACROSS RI AND EASTERN MA IT SHOULD REMAIN STORM-FREE
WITH MID LEVEL RIDGE LINGERING HOLDING THE CAP IN THE PLACE ALONG
WITH WEAKENING DEEP LAYER SHEAR.
GIVEN THE INCREASED FORECAST CONFIDENCE WE INSERTED INTO THE
FORECAST ENHANCED WORDING OF STRONG TO DAMAGING WINDS POSSIBLE
ALONG WITH LARGE HAIL AND HEAVY RAIN.
OTHERWISE FORECAST REMAINS ON TRACK WITH SUMMERTIME AIRMASS OVER
THE REGION. 925 MB TEMPS OF +25C/+26C AIRMASS ABOUT +3 STD WARMER
THAN CLIMO!
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
TONIGHT...
AS THE UPPER RIDGE STARTS TO SHIFT E TONIGHT...WILL SEE WINDS
START TO BACK TO SW AT THAT LEVEL AS THE HEIGHTS START TO FALL.
THIS MAY ALLOW FOR CONVECTION TO KICK OFF WITH SOME RELEASE OF ALL
THE DYNAMIC ENERGY WITH THE PASSING ELEVATED MIXED LAYER /EML/.
HOWEVER...LOOKS LIKE THE BEST LAPSE RATES PASS TO THE E BUT COULD
STILL SEE SOME STRONG CONVECTION...ALONG WITH HIGH CAPE VALUES.
WOULD BE BEST WITH DIURNAL INFLUENCES...BUT COULD SEE SOME HEAVY
RAIN AND GUSTY WINDS WITH THIS...PROBABLY AFTER MIDNIGHT. AGAIN...
WILL NEED TO MONITOR TODAY/S MODEL RUNS FOR TIMING AND POTENTIAL.
HAVE KEPT CHANCE POPS GOING ACROSS INLAND AREAS WHERE BEST
INSTABILITY OCCURS...WITH THE BEST SHOT ACROSS S NH/NW MA.
ANOTHER WARM AND MUGGY NIGHT EXPECTED WITH PATCHY FOG DEVELOPING.
OVERNIGHT LOWS IN THE MID 60S TO LOWER 70S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
BIG PICTURE...
THURSDAY STARTS WITH A DIGGING UPPER TROUGH OVER THE GREAT LAKES AND
NORTHEAST USA WHILE UPPER RIDGE SITS OVER THE PLAINS AND NORTHERN
ROCKIES. THE NORTHEAST TROUGH LINGERS OVER NEW ENGLAND THROUGH
SATURDAY...THEN LIFTS OUT THROUGH THE MARITIMES ON SUNDAY. A
SHORTWAVE FROM THE ARCTIC COAST OF CANADA SWEEPS SOUTHEAST AND
ACROSS NEW ENGLAND EARLY NEXT WEEK MAINTAINING CYCLONIC FLOW OVER
THE REGION. THE PLAINS RIDGE THEN SHIFTS EAST AT THE END OF THE
FORECAST PERIOD SPREADING DRIER WEATHER OUR WAY.
THE DAILIES...
THURSDAY...SURFACE COLD FRONT DRIVEN EAST BY THE GREAT LAKES
UPPER TROUGH. THE COLD FRONT WILL CROSS NEW YORK STATE DURING THE
DAY. BY EVENING THE VARIOUS MODELS HAVE THE FRONT EITHER AT OR
NEAR THE NY/CT/MASS BORDER WITH SIGNS OF A PRE-FRONTAL SURFACE
TROUGH FARTHER EAST. JET DYNAMICS ARE FAVORABLE WITH UPPER
DIVERGENCE OVERLAYING LOW LEVEL CONVERGENCE. WIND FIELDS FROM 850
MB TO 500 MB ARE FAVORABLE WITH 40-50 KNOTS AT 500. INSTABILITY IS
PRESENT WITH SBCAPE INITIALLY FORECAST AT 2000-2500 J/KG IN A BAND
FROM SOUTHERN NH TO NORTHWEST CT...TOTALS AROUND 50. ALL OF THIS
SUPPORTS MAINTAINING LIKELY POPS FOR SHOWERS/TSTMS WITH THIS
FROPA...WITH POTENTIAL FOR STRONG WIND GUSTS FROM TSTMS.
PRECIPITABLE WATER VALUES AROUND 1.8 INCHES SUGGESTS HEAVY
DOWNPOURS AS WELL.
STRONGEST INSTABILITY AND PRE-FRONTAL TROUGH STARTING IN OUR WESTERN
AREAS...SO WE WILL FOCUS HIGHEST POPS IN THAT AREA INITIALLY AND
THEN SWEEP POPS EAST LATER IN THE DAY AND AT NIGHT AS THE COLD FRONT
ENTERS NEW ENGLAND AND SLOWLY MOVES ACROSS AT NIGHT. DAYTIME
HEATING/MIXING SHOULD REACH TO AT LEAST 850 MB. TEMPS AT THAT LEVEL
WILL BE 14-16C WHICH WOULD SUPPORT MAX TEMPS IN THE MID 80S. CLOUDS
MAY KEEP TEMPS A LITTLE LESS WARM THAN FULL POTENTIAL...SO FORECAST
WILL RANGE FROM UPPER 70S TO MID 80S. WINDS AT 850 MB WILL BE 20-25
KNOTS...SO WE WILL ALSO INCLUDE WIND GUSTS TO THOSE SPEEDS.
FRIDAY... THE DIGGING TROUGH TURNS THE UPPER FLOW OVER NEW ENGLAND
MORE SOUTHWEST AND PARALLEL TO THE SURFACE FRONT...PROVIDING LESS
PUSH ACROSS THE FRONT AND THUS SLOWING IT DOWN. MODEL CONSENSUS HAS
THE FRONT IN EASTERN MASS FRIDAY MORNING AND SLOWLY MOVING OFFSHORE
BY AFTERNOON. THIS WILL KEEP A CHANCE OF SHOWERS/TSTMS DURING THE
MORNING ESPECIALLY IN THE EAST. THIS CHANCE DIMINISHES AS THE FRONT
MOVES OFFSHORE. CLEARING BY MIDDAY WITH ALLOW DAYTIME HEATING...BUT
THE UPPER TROUGH AND ITS COLD POOL WILL BE MOVING OVERHEAD DURING
THE AFTERNOON WITH PLENTY OF COLD ADVECTION ALOFT DESTABILIZING THE
AIRMASS. THE RESULT SHOULD BE CUMULUS DEVELOPMENT AND SCATTERED
SHOWERS.
SATURDAY-SUNDAY... HIGH PRESSURE BUILDS OVER THE REGION. COULD BE
SOME LEFTOVER CUMULUS DEVELOPMENT ON SATURDAY...DUE TO THE LINGERING
PRESENCE OF THE UPPER TROUGH/COLD POOL. THIS MOVES OFF BY SUNDAY.
MONDAY... SHORTWAVE FROM NORTHERN CANADA DRIVES ANOTHER COLD FRONT
INTO NEW ENGLAND. LIMITED MOISTURE WITH THIS FRONT BUT ENOUGH TO
GO WITH SLIGHT CHANCE POPS DURING FROPA.
TUESDAY...
HIGH PRESSURE RETURNS WITH FAIR DRY WEATHER.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
1030 AM UPDATE...
TODAY...VFR CONDITIONS THROUGH THE DAY. LOW TO MODERATE RISK OF
SHOWERS/TSTMS AFTER 22Z ACROSS WESTERN NEW ENGLAND. EASTERN MA AND
RI SHOULD REMAIN STORM-FREE.
TONIGHT...CLOUDS AND PATCHY FOG REDEVELOP IN HUMID AIRMASS. SHOULD
SEE AREAS OF MVFR-IFR CIGS/VSBYS...WITH LOWEST CONDITIONS ACROSS
INTERIOR E AND S CENTRAL MA/MOST OF IR INTO NE CT. HIGH
UNCERTAINTY FOR DEVELOPMENT OF CONVECTION. IF ANY TSTMS DEVELOP...
BEST LOCATIONS ACROSS S NH/N CENTRAL AND W MA/N CENTRAL CT.
STRONG WIND AND HEAVY RAINFALL POSSIBLE ALONG WITH LOCAL IFR
CONDITIONS.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. MVFR VSBYS IMPROVE TO
VFR. VFR TODAY INTO EARLY TONIGHT. LOW CHANCE OF A THUNDERSTORM
AFTER MIDNIGHT. MVFR-IFR CONDITIONS POSSIBLE IN FOG AFTER 08Z.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. IFR VSBYS EARLY
IMPROVING TO VFR TODAY. LOW CHANCE OF A THUNDERSTORM THIS EVENING
AND TONIGHT. MVFR VSBYS IN PATCHY FOG POSSIBLE AFTER 06Z.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY...AREAS OF IFR CIGS/VSBYS IN MORNING FOG. OTHERWISE VFR
WITH BRIEFLY LOWER CONDITIONS IN DEVELOPING SHOWERS/TSTMS ESPECIALLY
IN THE AFTERNOON AND AT NIGHT. SOUTHWEST WINDS WILL GUST TO 25 KNOTS
IN THE AFTERNOON. SOME THUNDERSTORMS WILL HAVE STRONGER WIND GUSTS
AS WELL AS HEAVY DOWNPOURS.
FRIDAY...COLD FRONT MOVES OFFSHORE IN THE MORNING AND WINDS WILL
SHIFT NORTHWEST WITH GUSTS TO 20 KNOTS. MORNING SHOWERS/TSTMS
ESPECIALLY IN EASTERN MASS AND RI. CLEARING AROUND MIDDAY WITH MORE
CLOUDS/SCATTERED SHOWERS DEVELOPING IN THE AFTERNOON ESPECIALLY
NORTH OF THE MASS TURNPIKE.
SATURDAY-SUNDAY...VFR AS HIGH PRESSURE BUILDS OVERHEAD. COULD BE
SOME LINGERING CLOUDS SATURDAY BUT GENERALLY VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH WEDNESDAY NIGHT/...HIGH CONFIDENCE.
TODAY...SW WINDS GUSTING UP TO 20 KT. PATCHY FOG WILL DISSIPATE BY
MID MORNING. SMALL CRAFT FOR 5 FOOT SEAS ON OUTER WATERS.
TONIGHT...SW WINDS CONTINUE WITH SEAS AROUND 5 FT ON THE OUTER
WATERS. ISOLD SHOWERS/TSTMS POSSIBLE ON EASTERN WATERS. PATCHY FOG
LIMITING VSBY. S-SE SWELLS BEGIN TO INCREASE FROM TS GABRIELLE.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THURSDAY...INCREASING CHANCE OF SHOWERS/TSTMS THROUGH THE DAY AND AT
NIGHT AS A COLD FRONT APPROACHES FROM THE WEST. SOUTHWEST WINDS AT
5000 FEET ABOVE THE SURFACE REACH 30 KNOTS...AND WE EXPECT MUCH OF
THIS TO REACH THE SURFACE BY AFTERNOON ESPECIALLY CLOSE TO LAND.
SMALL CRAFT ADVISORY WILL CONTINUE THROUGH THE DAY. IN
ADDITION...THE SOUTHWEST WIND WILL DRIVE 5-6 FOOT SEAS ON THE
EXPOSED WATERS.
FRIDAY... COLD FRONT MOVES OFFSHORE IN THE MORNING. WINDS WILL TURN
NORTHWEST WITH GUSTS IN THE LOW 20S. THERE IS A LOW CHANCE THAT
WINDS COULD REACH 25 KNOTS. LINGERING 5-6 FOOT SEAS...MAINLY ON THE
SOUTHERN AND SOUTHEAST OUTER WATERS.
SATURDAY-SUNDAY...HIGH PRESSURE BUILDS OVER NEW ENGLAND OVER THE
WEEKEND. THIS WILL BRING DIMINISHING WINDS AND SEAS. COULD BE A
FEW LINGERING 20 KNOT GUSTS AND 5 FOOT SEAS FIRST THING SATURDAY BUT
THE TREND WILL BE LOWER THROUGH THE DAY.
&&
.CLIMATE...
RECORD MAX TEMPS FOR WED 9/11...
BOS 99/1983
PVD 100/1983
BDL 99/1983
ORH 91/1983
90S IN SEPTEMBER? WELL...YES. BOS AND BDL HAVE EVEN HAD THEM IN
OCTOBER.
LATEST MAX TEMP OF 90 OR HIGHER...
BOS OCTOBER 12 1954
PVD SEPTEMBER 23 1970
BDL OCTOBER 17 1908
ORH SEPTEMBER 26 1930
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR CTZ002>004.
MA...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM EDT THIS
EVENING FOR MAZ005>007-013>019.
AIR QUALITY ALERT UNTIL 11 PM EDT THIS EVENING FOR MAZ007-
010>012-014.
NH...HEAT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 PM EDT THIS
EVENING FOR NHZ012.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 6 PM EDT THURSDAY FOR
ANZ231>234-251.
SMALL CRAFT ADVISORY FROM 2 PM TO 6 PM EDT THURSDAY FOR ANZ230-
236.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT THURSDAY FOR ANZ235-
237.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ250-
254>256.
&&
$$
SYNOPSIS...WTB/EVT
NEAR TERM...NOCERA
SHORT TERM...EVT
LONG TERM...WTB
AVIATION...WTB/NOCERA/EVT
MARINE...WTB/EVT
CLIMATE...
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1020 AM EDT Wed Sep 11 2013
...Forecast Update...
Issued at 1019 AM EDT Wed Sep 11 2013
Morning water vapor imagery shows what appears to be a deformation
axis across central KY this morning. This deformation is
superimposed on top of a surface moisture convergence axis that
stretches from SW TN through NE KY. Combination of mid-level
cloudiness and developing Cu have kept temperatures down a little
bit over the central and western sections of the forecast
area...while clear slot over our eastern sections is allowing
destabilization to take place. Temperatures were generally in the
middle to upper 70s.
Convection has already started to pop in the areas where a weaker
cap is in place. Convection was noted up around the Dayton OH area
with a secondary batch developing just northwest of Nashville TN.
Expect the area between these two points to gradually fill in with
convection this afternoon. Unlike yesterday, the highest coverage
of PoPs will likely be along and east of I-65 this afternoon and
evening. Convection is not forecast to be severe in nature.
However, high atmospheric moisture content will result in
low-centroid efficient rainers with gusty winds and quite a bit of
CG lightning.
Current forecast has these ideas well covered and only a minor
grid/forecast update was performed...mainly to lower temperatures
slightly in the hourly T/Td to better match current observations.
Highs today look to be a few degrees cooler than Tuesday with
readings generally in the upper 80s...though a few spots may hit the
lower 90s.
.SHORT TERM (Now through Thursday)...
Issued at 310 AM EDT Wed Sep 11 2013
This morning area obs show light patchy fog. Expect this light fog
to continue to develop and persist through the pre-dawn hours
especially in fog prone areas and locations where it rained
yesterday. Don`t expect to see any dense fog as winds aloft are
mixy.
For the rest of the day, expect convection to develop this morning
over southwest Indiana/southern IL/western KY and spread eastward
through the morning hours to at least Louisville/Bowling Green and
then closer to Lexington by early afternoon. Did go ahead and bump
up timing on POPs based on 0Z NAM and latest RAP guidance. These
models did a good job with yesterday`s convection, and both seem to
agree with an area of moisture convergence and isentropic lift
developing early this morning to kick off storms. This matches SPC
deep moisture convergence mesoanalysis well. Once convection gets
going, the environment looks favorable for strong storms similar to
yesterday. The strongest storms may contain wind gusts up to 40
mph, torrential rainfall, and frequent lightning. Slow storm
motions today combined with heavy rainfall may cause minor flooding
issues especially in areas that received a lot of rainfall
yesterday. With anticipated convection a little earlier than
previously thought, did go on the cooler side of temps for highs
today especially over central KY which will probably be cloudy or
rainy much of the late morning and afternoon hours. Southern
Indiana may clear out early enough to cause temps to rebound near
peak heating. Therefore will go with a gradient of lower 90s across
southern Indiana to mid 80s over portions of central KY.
Expect a dry period tonight as today`s convection will decline with
the loss of diurnal heating/instability. Low temps will remain mild
in the upper 60s and lower 70s.
For Thurs, a cold front will cross the area bringing sct-numerous
storms. With good instability and better wind shear along the base
of an upper level trough, we`ll likely see better storm
organization. With 0-6 km bulk shear values ranging from 25-35 kts,
multicells and perhaps some bowing segments may be possible. Steep
lapse rates and dry lower levels are supportive of a damaging wind
threat. As previously mentioned, though, the bulk of the better
wind shear values looks to lag behind the main line of convection
limiting the possibility for widespread damaging winds. Still will
need to keep an eye on the potential for severe storms Thurs. With
PWATs remaining high, storms will likely contain torrential rainfall
although they should have more movement to them than storms today.
Frequent lightning will also be likely. With the front gradually
making its way south through the area on Thurs providing for plenty
of clouds and on and off convection, temps should be limited to the
mid 80s for highs.
.LONG TERM (Thursday night through Tuesday)...
Issued at 313 AM EDT Wed Sep 11 2013
Thursday night - Sunday night:
A big cooldown is coming this weekend after the passage of a cold
front Thursday/Thursday night. Have left some lingering chances for
precip in the forecast for the beginning half of Thursday night
primarily for southern KY as the front makes its way south and out
of the forecast area. By sunrise Friday morning, the rain will have
completely exited, leaving skies to clear and much cooler temps
behind. Afternoon highs are currently forecast to range from the low
to mid 70s, continuing on the same track of utilizing raw model
guidance as did the previous forecaster. Regardless of exactly how
cool highs will be for both Friday and Saturday, NCEP 850mb
temperature ensemble guidance clearly depicts the probability of
below normal anomalies at or greater than 1 standard deviation. As
surface high pressure of Canadian origin settles in over the Ohio
Valley by Saturday, have gone just a couple of degrees cooler on
Saturday versus Friday, which means that portions of the Bluegrass
region could potentially struggle to reach the 70 degree mark. Am a
little concerned that this could be a bit too low but given the
lowering sun angles for this time of year and the fact that we are
inching closer to autumn, am sticking with the raw model guidance
currently provided. This means that under plenty of nighttime
radiational cooling, lows will flirt with the 50 degree mark for
Friday and Saturday night with some notoriously cooler spots
potentially dipping down into the upper 40s. Will certainly need to
continue to monitor model trends and the incoming CAA to nail down
specific highs and lows. By Sunday, the strong surface high will
begin to weaken its grip over the Ohio Valley and traverse eastward,
off of the eastern seaboard. This allows for southerly flow to
recommence and will begin to be felt as highs on Sunday reach the
upper 70s. Sunday night lows will respond, only dropping into the
upper 50s to lower 60s.
Monday - Tuesday night:
Models diverge from each other for this time period as the ECMWF
shows a stronger upper ridge over the Deep South extending into our
neck of the woods whereas the GFS generally keeps us under zonal
flow at the 500mb level with slight perturbations rippling through
early next week. At the surface, it appears as though the region
could see the next fropa coming through on Monday but then
potentially stalling out in the vicinity of the KY-TN border.
Significant differences temporally and spatially yield a low
confidence forecast at this juncture. A few members of the GEFS hint
at precip on Monday and given that we`ll see an uptick in
lower-level moisture under southerly flow, cannot entirely rule out
the possibility of at least diurnally-driven convection on Monday
afternoon and have therefore introduced slight chance PoPs as such.
Have kept Tuesday/Tuesday night dry area-wide for now as the front
potentially remains to the south of the forecast area. Temps look to
rebound to near normal for this time frame.
&&
.AVIATION (12Z TAF Update)...
Issued at 630 AM EDT Wed Sep 11 2013
The first TAF concern will be light patchy fog near BWG/LEX this
morning. Both terminals have experienced MVFR vsbys with BWG even
dropping into the IFR cat briefly. Think that MVFR will be the
primary restriction at BWG/LEX over the next few hours.
The next concern for all TAF sites will be convection chances for
today. Since storms are anticipated to be scattered in nature
will hold off on VCTS mention. Will go ahead and use VCSH to
highlight the best time period for possible convection. 0Z NAM and
latest high-res model guidance has trended earlier with convective
development for today. According to these models showers/storms
should develop near the I-65 corridor on the nose of good isentropic
lift aloft after sunrise this morning and push eastward throughout
the afternoon hours. Thus will highlight mid morning through the
afternoon for BWG/SDF for convection chances and mainly just the
afternoon hours for LEX.
Sfc winds will remain out of the SW increasing to 6-8 kts this
afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJ
Short Term.....AMS
Long Term......lg
Aviation.......AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
632 AM EDT Wed Sep 11 2013
...Updated Aviation Discussion...
.SHORT TERM (Now through Thursday)...
Issued at 310 AM EDT Wed Sep 11 2013
This morning area obs show light patchy fog. Expect this light fog
to continue to develop and persist through the pre-dawn hours
especially in fog prone areas and locations where it rained
yesterday. Don`t expect to see any dense fog as winds aloft are
mixy.
For the rest of the day, expect convection to develop this morning
over southwest Indiana/southern IL/western KY and spread eastward
through the morning hours to at least Louisville/Bowling Green and
then closer to Lexington by early afternoon. Did go ahead and bump
up timing on POPs based on 0Z NAM and latest RAP guidance. These
models did a good job with yesterday`s convection, and both seem to
agree with an area of moisture convergence and isentropic lift
developing early this morning to kick off storms. This matches SPC
deep moisture convergence mesoanalysis well. Once convection gets
going, the environment looks favorable for strong storms similar to
yesterday. The strongest storms may contain wind gusts up to 40
mph, torrential rainfall, and frequent lightning. Slow storm
motions today combined with heavy rainfall may cause minor flooding
issues especially in areas that received a lot of rainfall
yesterday. With anticipated convection a little earlier than
previously thought, did go on the cooler side of temps for highs
today especially over central KY which will probably be cloudy or
rainy much of the late morning and afternoon hours. Southern
Indiana may clear out early enough to cause temps to rebound near
peak heating. Therefore will go with a gradient of lower 90s across
southern Indiana to mid 80s over portions of central KY.
Expect a dry period tonight as today`s convection will decline with
the loss of diurnal heating/instability. Low temps will remain mild
in the upper 60s and lower 70s.
For Thurs, a cold front will cross the area bringing sct-numerous
storms. With good instability and better wind shear along the base
of an upper level trough, we`ll likely see better storm
organization. With 0-6 km bulk shear values ranging from 25-35 kts,
multicells and perhaps some bowing segments may be possible. Steep
lapse rates and dry lower levels are supportive of a damaging wind
threat. As previously mentioned, though, the bulk of the better
wind shear values looks to lag behind the main line of convection
limiting the possibility for widespread damaging winds. Still will
need to keep an eye on the potential for severe storms Thurs. With
PWATs remaining high, storms will likely contain torrential rainfall
although they should have more movement to them than storms today.
Frequent lightning will also be likely. With the front gradually
making it`s way south through the area on Thurs providing for plenty
of clouds and on and off convection, temps should be limited to the
mid 80s for highs.
.LONG TERM (Thursday night through Tuesday)...
Issued at 313 AM EDT Wed Sep 11 2013
Thursday night - Sunday night:
A big cooldown is coming this weekend after the passage of a cold
front Thursday/Thursday night. Have left some lingering chances for
precip in the forecast for the beginning half of Thursday night
primarily for southern KY as the front makes its way south and out
of the forecast area. By sunrise Friday morning, the rain will have
completely exited, leaving skies to clear and much cooler temps
behind. Afternoon highs are currently forecast to range from the low
to mid 70s, continuing on the same track of utilizing raw model
guidance as did the previous forecaster. Regardless of exactly how
cool highs will be for both Friday and Saturday, NCEP 850mb
temperature ensemble guidance clearly depicts the probability of
below normal anomalies at or greater than 1 standard deviation. As
surface high pressure of Canadian origin settles in over the Ohio
Valley by Saturday, have gone just a couple of degrees cooler on
Saturday versus Friday, which means that portions of the Bluegrass
region could potentially struggle to reach the 70 degree mark. Am a
little concerned that this could be a bit too low but given the
lowering sun angles for this time of year and the fact that we are
inching closer to autumn, am sticking with the raw model guidance
currently provided. This means that under plenty of nighttime
radiational cooling, lows will flirt with the 50 degree mark for
Friday and Saturday night with some notoriously cooler spots
potentially dipping down into the upper 40s. Will certainly need to
continue to monitor model trends and the incoming CAA to nail down
specific highs and lows. By Sunday, the strong surface high will
begin to weaken its grip over the Ohio Valley and traverse eastward,
off of the eastern seaboard. This allows for southerly flow to
recommence and will begin to be felt as highs on Sunday reach the
upper 70s. Sunday night lows will respond, only dropping into the
upper 50s to lower 60s.
Monday - Tuesday night:
Models diverge from each other for this time period as the ECMWF
shows a stronger upper ridge over the Deep South extending into our
neck of the woods whereas the GFS generally keeps us under zonal
flow at the 500mb level with slight perturbations rippling through
early next week. At the surface, it appears as though the region
could see the next fropa coming through on Monday but then
potentially stalling out in the vicinity of the KY-TN border.
Significant differences temporally and spatially yield a low
confidence forecast at this juncture. A few members of the GEFS hint
at precip on Monday and given that we`ll see an uptick in
lower-level moisture under southerly flow, cannot entirely rule out
the possibility of at least diurnally-driven convection on Monday
afternoon and have therefore introduced slight chance PoPs as such.
Have kept Tuesday/Tuesday night dry area-wide for now as the front
potentially remains to the south of the forecast area. Temps look to
rebound to near normal for this time frame.
&&
.AVIATION (12Z TAF Update)...
Issued at 630 AM EDT Wed Sep 11 2013
The first TAF concern will be light patchy fog near BWG/LEX this
morning. Both terminals have experienced MVFR vsbys with BWG even
dropping into the IFR cat briefly. Think that MVFR will be the
primary restriction at BWG/LEX over the next few hours.
The next concern for all TAF sites will be convection chances for
today. Since storms are anticipated to be scattered in nature
will hold off on VCTS mention. Will go ahead and use VCSH to
highlight the best time period for possible convection. 0Z NAM and
latest high-res model guidance has trended earlier with convective
development for today. According to these models showers/storms
should develop near the I-65 corridor on the nose of good isentropic
lift aloft after sunrise this morning and push eastward throughout
the afternoon hours. Thus will highlight mid morning through the
afternoon for BWG/SDF for convection chances and mainly just the
afternoon hours for LEX.
Sfc winds will remain out of the SW increasing to 6-8 kts this
afternoon.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Short Term........AMS
Long Term.........lg
Aviation..........AMS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
936 AM EDT WED SEP 11 2013
.SYNOPSIS...
A COLD FRONT LOCATED FROM NORTHERN MICHIGAN TO EASTERN IOWA THIS
MORNING WILL MOVE SOUTH TODAY...REACHING NORTHERN OH/NW PA
THURSDAY MORNING. A SECONDARY TROUGH WILL MOVE THROUGH THURSDAY
AFTERNOON. A SIGNIFICANT AIRMASS CHANGE WILL TAKE PLACE...WITH
TEMPERATURES TURNING FROM ABOVE NORMAL HEAT TO A BELOW NORMAL
CHILL FOR FRIDAY INTO THE WEEKEND. HIGH PRESSURE WILL BE OVER THE
REGION SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MINOR CHANGES WITH THE GRIDS. PLENTY OF LOW LEVEL MOISTURE
OVER THE REGION THIS MORNING. HOWEVER IT APPEARS WE WILL BE ABLE
TO MIX SOME OF IT OUT THROUGH THE AFTERNOON WHICH SHOULD KEEP HEAT
INDEX VALUES BELOW ADVISORY LEVELS. CLOUD COVER HAS ALSO INCREASED
WHICH MAY ALSO SHAVE 2 TO 5 DEGREES FROM HIGHS COMPARED TO
YESTERDAY.
WE WILL HAVE TO MONITOR LOW LEVEL CONVERGENCE THIS AFTERNOON TO
SEE WHERE THE THUNDERSTORMS WILL INITIATE. MOST LIKELY WILL BE
LOCALLY INDUCED CONVERGENCE IN THE VICINITY OF THE HILLS ACROSS
THE CENTRAL HIGHLANDS AND FROM EXTREME NORTHEASTERN OHIO INTO NW
PA. THESE WILL LIKELY REMAIN ISOLATED. WE WILL HAVE TO MONITOR
ANYTHING THAT DEVELOPS SINCE CAPES WILL BE HIGH. SO THE STRONGEST
STORMS WILL HAVE THE CAPABILITY TO PRODUCE STRONG WIND GUSTS AND
MARGINALLY SEVERE HAIL.
PREVIOUS DISCUSSION...
A NUMBER OF ITEMS TO CONSIDER FOR TODAY. STRONG RIDGE OVER THE
OHIO VALLEY WILL BEGIN TO BREAK DOWN. A FRONTAL SYSTEM OVER THE
CENTRAL GREAT LAKES WILL BEGIN TO MAKE PROGRESS SOUTH...ALTHOUGH
SLOW AT FIRST. ONE INITIAL SHORTWAVE SHEARS OFF TO NEW ENGLAND
BRINGING THE FRONT INTO CENTRAL LOWER MI FOR THIS AFTERNOON. A
STRONGER SHORTWAVE COMING OUT OF SOUTH CENTRAL CANADA WILL CARVE
OUT THE TROUGH FOR THE GREAT LAKES AND GIVE THAT FRONT A PUSH
SOUTH OVERNIGHT. FIRST QUESTION BECOMES HOW MUCH IN THE WAY OF
SHOWERS/STORMS DO WE GET BEFORE 6P. AN AREA OF DEEPER MOISTURE
THAT 24 HRS AGO WAS NEAR PADUCAH IS NOW ACROSS SOUTHWEST OHIO.
MODEL GUIDANCE SHOWERS THAT A FEW SHOWERS/TS INITIATE WITH THIS
ACROSS OUR SOUTHEAST COUNTIES INCLUDING YOUNGSTOWN AND
AKRON/CANTON. HAVE FOCUSED SOME AFTERNOON PRECIP CHANCES THERE.
ALSO A LITTLE CONCERNED WITH AREA FROM FINDLAY TO MANSFIELD FOR AN
ISOLATED STORM. FINALLY SOME PREFRONTAL ACTIVITY IS POSSIBLE
ACROSS SE MI AND THEREFORE ALSO THE TOLEDO AREA. SPC SLIGHT RISK
IS ACROSS THE NORTHERN HALF OF THE AREA FOR STORMS LATE THIS
AFTERNOON AND EVENING. AGREE WITH THAT. NEXT QUESTION IS
TEMPERATURES. THE ONLY THING SAVING US FROM A REPEAT OF YESTERDAY
IS THE PRESENCE OF ADDITIONAL CLOUD COVER. THIS MAY BE JUST ENOUGH
TO KEEP US OUT OF HEAT ADVISORY TERRITORY. UPPER 80S ACROSS THE
SOUTHEAST TO LOWER 90S ACROSS THE I-75 CORRIDOR.
ONLY MINOR SKY COVER ADJUSTMENTS WERE MADE WITH THIS EARLY MORNING
UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
SO STRONGER SHORTWAVE THAT WILL AMPLIFY THE TROUGH ACROSS THE
GREAT LAKES WILL PUSH THE COLD FRONT SOUTH TONIGHT. AT 6 PM STORMS
MAY BE ONGOING ACROSS FAR NW OH OR BE CLOSE BY. SOME CONCERN FOR
SEVERE STORMS ESPECIALLY ACROSS THE LAKESHORE COUNTIES. WIND WOULD
BE THE PRIMARY THREAT. AREA WILL BECOME MODESTLY UNSTABLE AND
SHEAR WILL BEGIN TO INCREASE AS THE UPPER TROUGH APPROACHES. WILL
JUST HAVE TO WATCH FRONTAL TIMING AND ANY PREFRONTAL AREAS OF
CONVERGENCE. MARCH LIKELY AND CATEGORICAL PRECIP CHANCES SOUTHWARD
OVER THE COURSE OF THE NIGHT AND INTO THURSDAY MORNING.
CONTINUED PRECIPITATION CHANCES INTO MUCH OF THURSDAY. THERE ARE
INDICATIONS OF A SECONDARY TROUGH THAT MAY AID IN A FEW ADDITIONAL
SHOWERS/TS. THE COLD PUSH WITH THIS SYSTEM IS SLIGHTLY
DELAYED...AND IS ASSOCIATED MORE WITH THE SECONDARY TROUGH. SO
THURSDAY WILL TURN OUT NEAR NORMAL FOR HIGHS. THE BIG CHANGE COMES
FOR FRIDAY.
WHILE THERE MAY BE A LULL IN PRECIPITATION THURSDAY EVENING...AS
THE COLDER AIR FILTERS IN AND THE UPPER TROUGH APPROACHES...LAKE
EFFECT CONDITIONS BEGIN TO TAKE SHAPE. SCATTERED SHOWERS STARTING
LATE THURSDAY NIGHT AND CONTINUING INTO FRIDAY POSSIBLE. HAVE
RAISED POPS ACROSS NRN OH/NW PA. ALSO HAVE ADDED THE MENTION OF
ISOLATED THUNDER FOR EAST OF CLEVELAND. LAKE TO H5 TEMPERATURE
DIFFERENCE GREAT ENOUGH FOR THE POSSIBILITY OF THUNDER WITHIN THE
LAKE EFFECT SHOWERS. TEMPERATURES FRIDAY WILL STRUGGLE TO GET INTO
THE 60S...WITH SOME PARTS OF NW PA/FAR NE OH STAYING IN THE UPPER
50S.
LAKE EFFECT SHOWERS SHOULD BE CONFINED TO FRIDAY AND MAYBE FRIDAY
NIGHT. AFTER THAT RIDGING AND DRYING BEGIN TO WORK INTO THE AREA
ENDING THAT THREAT. TEMPS FRIDAY NIGHT TO BE IN THE 40S. WITH
CLEARING ACROSS THE WEST TEMPS WILL BE CLOSER TO 40. SATURDAY
HIGHS SIMILAR..60 TO 65. BY SATURDAY NIGHT MORE OF THE AREA WILL
BE CLEARER AND MORE LOWER 40S ARE EXPECTED. IT IS DEFINITELY
POSSIBLE TO GET UPPER 30S DEPENDING ON CLOUD COVER.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THIS PORTION OF THE EXTENDED DOES NOT LOOK VERY ACTIVE. HIGH
PRESSURE WILL BE MOVING EAST ON SUNDAY AND THAT WILL ALLOW A COLD
FRONT TO MOVE IN SUNDAY NIGHT INTO MONDAY BEFORE HIGH PRESSURE
BUILDS BACK IN. THE 00Z GFS AND ECMWF NOW AGREE WITH THIS SOLUTION.
AT THIS TIME KEPT THE POPS AROUND 20%. THIS MAY HAVE TO BE RAISED
SOME IF THE TREND REMAINS THE SAME. KEPT CLOSE TO HPC GUIDANCE FOR
THE TEMPERATURE FORECAST WHICH HAS SLIGHTLY BELOW NORMAL TEMPERATURES.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE BIG QUESTION IS THE TIMING OF THE THUNDERSTORMS FOR TODAY AND
TONIGHT. IN THE MEANTIME INCREASING MID AND HIGH CLOUDS FOR THE
MORNING. ANY FOG WILL DISSIPATE BY MID MORNING BUT SOME HAZE COULD
CONTINUE INTO THE AFTERNOON.
THE MODELS ARE FAIRLY CONSISTENT IN INCREASING THE LOW LEVEL
MOISTURE BY MID TO LATE MORNING OVER NE OH AND NW PA AND THEN
DEVELOPING SCATTERED SHOWERS AND THUNDERSTORMS. THIS IS OK...EVEN
THOUGH THE HRRR MODEL HAS BACKED DOWN ON THIS. AT THIS TIME JUST KEPT
IT THUNDER VICINITY. A LITTLE BREAK MAY OCCUR EARLY THIS EVENING
OVER NE OH AND NW PA WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING OVER NW OH AND SPREADING EAST AND THEN A BETTER CHANCE
OF SHOWERS AND THUNDERSTORMS AFTER MIDNIGHT AS THE FRONT
APPROACHES.
OUTLOOK...WILL LIKELY HAVE NON VFR CEILINGS ACROSS NE OH/NW PA
THURSDAY THROUGH FRIDAY.
&&
.MARINE...
SOME ACTIVE WEATHER FOR THE LAKE WILL BEGIN ESPECIALLY TONIGHT AND
LAST INTO FRIDAY. SOUTHWEST WINDS ON THE LAKE TODAY WILL STAY BELOW
SMALL CRAFT ADVISORY CONDITIONS EVEN ON THE EAST END. THE COLD FRONT
WILL MOVE ACROSS THE LAKE LATE TONIGHT AND EARLY THURSDAY MORNING.
SOME OF THE THUNDERSTORMS AHEAD OF THE FRONT WILL LIKELY PROMPT
SPECIAL MARINE WARNINGS TO BE ISSUED.
SOME QUESTION HOW QUICKLY THE WINDS WILL PICK UP ON THE LAKE
THURSDAY BEHIND THE COLD FRONT. WENT TOWARD THE FASTER GFS IN
INCREASING THE WINDS ESPECIALLY ON THE EAST END AND THEN THE WEST
END THURSDAY NIGHT. EVENTUALLY A SMALL CRAFT ADVISORY WILL BE NEEDED
ON MUCH OF LAKE ERIE. THE THREAT FOR A SMALL CRAFT ADVISORY
CONDITIONS WILL LAST INTO FRIDAY NIGHT. PLENTY OF COLD AIR WILL BE
FLOWING ACROSS THE LAKE AND THAT MAY GENERATE SOME WATERSPOUTS AND
THUNDER BESIDES THE SHOWERS ESPECIALLY ON FRIDAY AS THE LAKE AND 850
MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C AND THE LAKE AND 500 MB
TEMPERATURE DIFFERENCE WILL BE AROUND 40C.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SATURDAY AND THEN MOVE
EAST ON SUNDAY ALLOWING THE SOUTHWEST FLOW TO RETURN. A FRONT WILL
CROSS THE LAKE SUNDAY NIGHT INTO MONDAY SHIFTING THE WINDS TO
ONSHORE AS THE HIGH WILL TRY TO BUILD IN. THE WINDS AND WAVES ARE
EXPECTED TO BE BELOW SMALL CRAFT ADVISORY CONDITIONS EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
736 AM EDT WED SEP 11 2013
.SYNOPSIS...
A COLD FRONT LOCATED FROM NORTHERN LOWER MICHIGAN BACK TO
DES MOINES IOWA EARLY THIS MORNING WILL MOVE SOUTH
TODAY...REACHING NORTHERN OH/NW PA THURSDAY MORNING. A SECONDARY
TROUGH WILL MOVE THROUGH THURSDAY AFTERNOON. A SIGNIFICANT AIRMASS
CHANGE WILL TAKE PLACE...WITH TEMPERATURES TURNING FROM ABOVE
NORMAL HEAT TO A BELOW NORMAL CHILL FOR FRIDAY INTO THE WEEKEND.
HIGH PRESSURE WILL BE OVER THE REGION SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A NUMBER OF ITEMS TO CONSIDER FOR TODAY. STRONG RIDGE OVER THE
OHIO VALLEY WILL BEGIN TO BREAK DOWN. A FRONTAL SYSTEM OVER THE
CENTRAL GREAT LAKES WILL BEGIN TO MAKE PROGRESS SOUTH...ALTHOUGH
SLOW AT FIRST. ONE INITIAL SHORTWAVE SHEARS OFF TO NEW ENGLAND
BRINGING THE FRONT INTO CENTRAL LOWER MI FOR THIS AFTERNOON. A
STRONGER SHORTWAVE COMING OUT OF SOUTH CENTRAL CANADA WILL CARVE
OUT THE TROUGH FOR THE GREAT LAKES AND GIVE THAT FRONT A PUSH
SOUTH OVERNIGHT. FIRST QUESTION BECOMES HOW MUCH IN THE WAY OF
SHOWERS/STORMS DO WE GET BEFORE 6P. AN AREA OF DEEPER MOISTURE
THAT 24 HRS AGO WAS NEAR PADUCAH IS NOW ACROSS SOUTHWEST OHIO.
MODEL GUIDANCE SHOWERS THAT A FEW SHOWERS/TS INITIATE WITH THIS
ACROSS OUR SOUTHEAST COUNTIES INCLUDING YOUNGSTOWN AND
AKRON/CANTON. HAVE FOCUSED SOME AFTERNOON PRECIP CHANCES THERE.
ALSO A LITTLE CONCERNED WITH AREA FROM FINDLAY TO MANSFIELD FOR AN
ISOLATED STORM. FINALLY SOME PREFRONTAL ACTIVITY IS POSSIBLE
ACROSS SE MI AND THEREFORE ALSO THE TOLEDO AREA. SPC SLIGHT RISK
IS ACROSS THE NORTHERN HALF OF THE AREA FOR STORMS LATE THIS
AFTERNOON AND EVENING. AGREE WITH THAT. NEXT QUESTION IS
TEMPERATURES. THE ONLY THING SAVING US FROM A REPEAT OF YESTERDAY
IS THE PRESENCE OF ADDITIONAL CLOUD COVER. THIS MAY BE JUST ENOUGH
TO KEEP US OUT OF HEAT ADVISORY TERRITORY. UPPER 80S ACROSS THE
SOUTHEAST TO LOWER 90S ACROSS THE I-75 CORRIDOR.
ONLY MINOR SKY COVER ADJUSTMENTS WERE MADE WITH THIS EARLY MORNING
UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
SO STRONGER SHORTWAVE THAT WILL AMPLIFY THE TROUGH ACROSS THE
GREAT LAKES WILL PUSH THE COLD FRONT SOUTH TONIGHT. AT 6 PM STORMS
MAY BE ONGOING ACROSS FAR NW OH OR BE CLOSE BY. SOME CONCERN FOR
SEVERE STORMS ESPECIALLY ACROSS THE LAKESHORE COUNTIES. WIND WOULD
BE THE PRIMARY THREAT. AREA WILL BECOME MODESTLY UNSTABLE AND
SHEAR WILL BEGIN TO INCREASE AS THE UPPER TROUGH APPROACHES. WILL
JUST HAVE TO WATCH FRONTAL TIMING AND ANY PREFRONTAL AREAS OF
CONVERGENCE. MARCH LIKELY AND CATEGORICAL PRECIP CHANCES SOUTHWARD
OVER THE COURSE OF THE NIGHT AND INTO THURSDAY MORNING.
CONTINUED PRECIPITATION CHANCES INTO MUCH OF THURSDAY. THERE ARE
INDICATIONS OF A SECONDARY TROUGH THAT MAY AID IN A FEW ADDITIONAL
SHOWERS/TS. THE COLD PUSH WITH THIS SYSTEM IS SLIGHTLY
DELAYED...AND IS ASSOCIATED MORE WITH THE SECONDARY TROUGH. SO
THURSDAY WILL TURN OUT NEAR NORMAL FOR HIGHS. THE BIG CHANGE COMES
FOR FRIDAY.
WHILE THERE MAY BE A LULL IN PRECIPITATION THURSDAY EVENING...AS
THE COLDER AIR FILTERS IN AND THE UPPER TROUGH APPROACHES...LAKE
EFFECT CONDITIONS BEGIN TO TAKE SHAPE. SCATTERED SHOWERS STARTING
LATE THURSDAY NIGHT AND CONTINUING INTO FRIDAY POSSIBLE. HAVE
RAISED POPS ACROSS NRN OH/NW PA. ALSO HAVE ADDED THE MENTION OF
ISOLATED THUNDER FOR EAST OF CLEVELAND. LAKE TO H5 TEMPERATURE
DIFFERENCE GREAT ENOUGH FOR THE POSSIBILITY OF THUNDER WITHIN THE
LAKE EFFECT SHOWERS. TEMPERATURES FRIDAY WILL STRUGGLE TO GET INTO
THE 60S...WITH SOME PARTS OF NW PA/FAR NE OH STAYING IN THE UPPER
50S.
LAKE EFFECT SHOWERS SHOULD BE CONFINED TO FRIDAY AND MAYBE FRIDAY
NIGHT. AFTER THAT RIDGING AND DRYING BEGIN TO WORK INTO THE AREA
ENDING THAT THREAT. TEMPS FRIDAY NIGHT TO BE IN THE 40S. WITH
CLEARING ACROSS THE WEST TEMPS WILL BE CLOSER TO 40. SATURDAY
HIGHS SIMILAR..60 TO 65. BY SATURDAY NIGHT MORE OF THE AREA WILL
BE CLEARER AND MORE LOWER 40S ARE EXPECTED. IT IS DEFINITELY
POSSIBLE TO GET UPPER 30S DEPENDING ON CLOUD COVER.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THIS PORTION OF THE EXTENDED DOES NOT LOOK VERY ACTIVE. HIGH
PRESSURE WILL BE MOVING EAST ON SUNDAY AND THAT WILL ALLOW A COLD
FRONT TO MOVE IN SUNDAY NIGHT INTO MONDAY BEFORE HIGH PRESSURE
BUILDS BACK IN. THE 00Z GFS AND ECMWF NOW AGREE WITH THIS SOLUTION.
AT THIS TIME KEPT THE POPS AROUND 20%. THIS MAY HAVE TO BE RAISED
SOME IF THE TREND REMAINS THE SAME. KEPT CLOSE TO HPC GUIDANCE FOR
THE TEMPERATURE FORECAST WHICH HAS SLIGHTLY BELOW NORMAL TEMPERATURES.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE BIG QUESTION IS THE TIMING OF THE THUNDERSTORMS FOR TODAY AND
TONIGHT. IN THE MEANTIME INCREASING MID AND HIGH CLOUDS FOR THE
MORNING. ANY FOG WILL DISSIPATE BY MID MORNING BUT SOME HAZE COULD
CONTINUE INTO THE AFTERNOON.
THE MODELS ARE FAIRLY CONSISTENT IN INCREASING THE LOW LEVEL
MOISTURE BY MID TO LATE MORNING OVER NE OH AND NW PA AND THEN
DEVELOPING SCATTERED SHOWERS AND THUNDERSTORMS. THIS IS OK...EVEN
THOUGH THE HRRR MODEL HAS BACKED DOWN ON THIS. AT THIS TIME JUST KEPT
IT THUNDER VICINITY. A LITTLE BREAK MAY OCCUR EARLY THIS EVENING
OVER NE OH AND NW PA WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING OVER NW OH AND SPREADING EAST AND THEN A BETTER CHANCE
OF SHOWERS AND THUNDERSTORMS AFTER MIDNIGHT AS THE FRONT
APPROACHES.
OUTLOOK...WILL LIKELY HAVE NON VFR CEILINGS ACROSS NE OH/NW PA
THURSDAY THROUGH FRIDAY.
&&
.MARINE...
SOME ACTIVE WEATHER FOR THE LAKE WILL BEGIN ESPECIALLY TONIGHT AND
LAST INTO FRIDAY. SOUTHWEST WINDS ON THE LAKE TODAY WILL STAY BELOW
SMALL CRAFT ADVISORY CONDITIONS EVEN ON THE EAST END. THE COLD FRONT
WILL MOVE ACROSS THE LAKE LATE TONIGHT AND EARLY THURSDAY MORNING.
SOME OF THE THUNDERSTORMS AHEAD OF THE FRONT WILL LIKELY PROMPT
SPECIAL MARINE WARNINGS TO BE ISSUED.
SOME QUESTION HOW QUICKLY THE WINDS WILL PICK UP ON THE LAKE
THURSDAY BEHIND THE COLD FRONT. WENT TOWARD THE FASTER GFS IN
INCREASING THE WINDS ESPECIALLY ON THE EAST END AND THEN THE WEST
END THURSDAY NIGHT. EVENTUALLY A SMALL CRAFT ADVISORY WILL BE NEEDED
ON MUCH OF LAKE ERIE. THE THREAT FOR A SMALL CRAFT ADVISORY
CONDITIONS WILL LAST INTO FRIDAY NIGHT. PLENTY OF COLD AIR WILL BE
FLOWING ACROSS THE LAKE AND THAT MAY GENERATE SOME WATERSPOUTS AND
THUNDER BESIDES THE SHOWERS ESPECIALLY ON FRIDAY AS THE LAKE AND 850
MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C AND THE LAKE AND 500 MB
TEMPERATURE DIFFERENCE WILL BE AROUND 40C.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SATURDAY AND THEN MOVE
EAST ON SUNDAY ALLOWING THE SOUTHWEST FLOW TO RETURN. A FRONT WILL
CROSS THE LAKE SUNDAY NIGHT INTO MONDAY SHIFTING THE WINDS TO
ONSHORE AS THE HIGH WILL TRY TO BUILD IN. THE WINDS AND WAVES ARE
EXPECTED TO BE BELOW SMALL CRAFT ADVISORY CONDITIONS EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1111 AM EDT WED SEP 11 2013
.SYNOPSIS...
AN UNSEASONABLY HOT AND HUMID AIR MASS WILL REMAIN OVER THE REGION
TODAY...WITH AFTERNOON TEMPERATURES 10 TO 15 DEGREES ABOVE NORMAL
FOR EARLY SEPTEMBER. RELIEF FROM THE LATE-SUMMER HOT SPELL WILL
ARRIVE ON THURSDAY...AS A COLD FRONT BRINGS NUMEROUS THUNDERSTORMS
TO THE AREA...FOLLOWED BY ANOTHER TASTE OF FALL WITH BELOW NORMAL
TEMPERATURES EXPECTED FROM FRIDAY INTO THE UPCOMING WEEKEND.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
HAZY AND UNCOMFORTABLE AIR WITH 78F DEWPOINT AT KLNS AND
WIDESPREAD L70 DEWPOINTS ELSEWHERE. THE TEMPS ARE GETTING NEAR THE
CONVECTIVE TEMP...AND CU ALREADY GROWING VERY TALL OVER THE
LAURELS. CAPES CRAZY HIGH PER LATEST RUC AND VERIFYING EARLIER
FCSTS. SO THE GOING FCST HAS BEEN HELD INTACT SAVE FOR A BUMP IN
THE POPS FOR THE HIGHER ELEVATIONS WHERE CONFIDENCE HAS INCREASED.
TWEAK OR TWO TO SKY COVER AS WELL. ONE BLIP ON PPI OVER INDIANA CO
IS LIKELY JUST THE FIRST OF THE SCT SHRA TO DEVELOP SHORTLY. EARLY
CONVECTION ALONG THE ALLEGHENIES SIMILARLY FCST TO DO THE SPLIT TO
THE EAST AND NORTH AND MAY AVOID MY CRISPY BROWN LAWN.
DESPITE PWATS NEAR 2 INCHES...WIND PROFILE LENDS ITSELF TO STORM
MOTION STEADY BUT SLOW TO THE NORTHEAST. THUS...NO TRAINING
EXPECTED AND SHOWERS SHOULD BE BRIEF.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE GUIDANCE IS DEPICTING AN INTERESTING MESOSCALE SET-
UP...SHOWING THE BULK OF CONVECTIVE PCPN FOCUSED ALONG THE
ALLEGHENIES...WHERE IT APPEARS COOLER MID-LVL TEMPS AND TERRAIN-
INDUCE LIFT MAY OFFSET SFC MESO RIDGING. THE HIGHER INSTABILITY
AND STEEPER LAPSE RATES ARE FCST E OF THE MTNS ALONG A PRE-
FRONTAL/LEE TROUGH AXIS CENTERED NEAR/ALONG THE SUSQ RIVER.
HOWEVER..700MB TEMPS SHOULD BE SLIGHTLY WARMER TO THE EAST WHICH
MAY ACT TO "CAP" THINGS OFF. FWIW...THE LATEST COSPA (HRRR+RAP)
DATA FAVORS THE ERN SLOPES OF THE ALLEGHENIES CLOSER TO THE LEE-
TROF AXIS. THE SWODY1 HAS NRN PA IN THE SLGT RISK...WHICH IS
LOCATED ON THE SRN EDGE OF THE BETTER WLY DEEP LYR SHEAR LOCATED
ACRS NY AND NEW ENGLAND. GIVEN LOW CONFIDENCE IN THE MESO
DETAILS...WENT WITH A BROAD-BRUSHED APPROACH WITH POPS AND WILL
ALLOW THE DAYSHIFT TO REFINE BASED ON RADAR TRENDS. IT WILL BE
ANOTHER HAZY HOT AND HUMID LATE-SUMMER DAY WITH MAXES IN THE
85-90F RANGE OR +10-15 DEGREES ABOVE EARLY SEPT. NORMALS. SOME
LOCATIONS COULD APPROACH/EXCEED DAILY RECORD HIGHS.
THERE SHOULD BE A LULL IN CONVECTIVE ACTIVITY AFTER DARK AS THE
BLYR COOLS/DESTABILIZES. FOCUS WILL SHIFT TO APPROACHING COLD FRONT
PUSHING SEWD ACRS THE LOWER GREAT LAKES...WITH THE HIGHEST POPS
OVER THE NW MTNS LATE TONIGHT INTO EARLY THU. IT WILL BE ANOTHER
MUGGY OVERNIGHT AND EARLY MORNING WITH LOWS 65-70F AND PATCHY
FOG/HAZE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
UPPER RIDGING AND CONTINUING PRESENCE OF SURFACE HIGH PRESSURE
FROM CANADA WILL KEEP PENNSYLVANIA MAINLY DRY THROUGH THE LONG
TERM PERIOD. DEEP UPPER TROF OVER THE CENTRAL AND EASTERN GREAT
LAKES TO START THE PERIOD WILL LIFT OUT INTO NEW ENGLAND FRIDAY
AND SATURDAY...ALLOWING UPPER HEIGHTS TO BECOME MORE ZONAL
THROUGH THE REMAINDER OF PERIOD.
AT THE SURFACE...A COLD FRONT SHOULD BE EXITING TO THE EAST AT THE
START OF THE PERIOD ON FRIDAY...WITH THE FIRST LARGE SFC
ANTICYCLONE BUILDING IN THROUGH THE WEEKEND.
A WEAK SHORTWAVE IS PROGGED TO DROP THROUGH THE UPPER FLOW SOMETIME
MONDAY BRINGING ANOTHER FRONT. THE WEAKNESS OF THE SYSTEM AND THE
DRYNESS OF THE AIR IN PLACE BRINGING INTO QUESTION HOW MUCH PCPN MAY
ACCOMPANY THE FRONT...SO KEPT MINIMAL POPS ATTM. THE SECOND
ANTICYCLONE FOLLOWS TUE INTO WEDNESDAY FOR YET MORE DRY WEATHER.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
EXPECT MVFR-IFR VISBYS IN HZ TO IMPROVE TO VFR THRU THE
MORNING...GIVING WAY TO ANOTHER HAZY HOT AND HUMID DAY. TEMPS
ALOFT ARE NOT AS WARM AS YESTERDAY WHICH FAVORS A WEAKER CAP...AND
BETTER CHANCE FOR SCATTERED AFTERNOON TSTORMS. LATEST COSPA/CCFP
FAVORS CORRIDOR FROM JST-AOO TO UNV-IPT WITH TSTM IMPACT BTWN
17-19Z.
TSTORMS SHOULD WEAKEN AND DISSIPATE INTO TONIGHT/00-04Z. LLVL MSTR
WILL REMAIN VERY HIGH OVERNIGHT AND LKLY RESULT SOME MVFR VISBYS.
THE FOCUS WILL SHIFT TO A WELL-DEFINED COLD FRONT PUSHING SEWD
FROM THE LWR LKS. EXPECT THIS BOUNDARY TO BE CONVECTIVELY ACTIVE
AS IT CROSSES THE AIRSPACE ON THURSDAY...WITH THE POTENTIAL FOR
STG TO SVR TSTORMS.
OUTLOOK...
THU...SCT-NMRS TSTM IMPACTS PSBL WITH COLD FROPA.
FRI...MVFR/SCT SHOWERS PSBL N/W...VFR CENTRAL/EAST. BREEZY.
SAT-SUN...VFR. NO SIG WX.
&&
.EQUIPMENT...
BFD OBS HAVE BEEN RESTORED BY FAA WORK.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DANGELO/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...DEVOIR/GARTNER
AVIATION...DANGELO/STEINBUGL
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS PUEBLO CO
352 PM MDT WED SEP 11 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM MDT WED SEP 11 2013
.TONIGHT...NEXT BATCH OF CONVECTION HAS DEVELOPED OVER SOUTHERN
PUEBLO COUNTY AND IS MOVING NORTHWARD. LATEST HRRR SUGGESTS THIS
CONVECTION WILL WEAKEN DURING THE NEXT HOURLY...BUT HRRR PERFORMANCE
HAS NOT BEEN STELLAR TODAY. MODELS HAVE BEEN DOING A BETTER JOB WITH
THE CONVECTION ON THE EASTERN PLAINS...AND THERE IS A CONSENSUS OF
MOST OF THE PRECIPITATION MOVING TO THE NORTHEAST DURING THE
EVENING. OVER THE CONTINENTAL DIVIDE REGION....SOME STORMS HAVE
FINALLY DEVELOPED AS WATER VAPOR SHOWS A DISTURBANCE MOVING INTO
CENTRAL COLORADO. DECIDED TO MAINTAIN MOSTLY HIGH SCATTERED POPS
DURING THE NIGHT. SUSPECT THE DISTURBANCE OVER CENTRAL COLORADO
WILL MOVE ACROSS THE REGION THIS EVENING..WHICH WILL DEVELOP SOME
SHOWERS THIS EVENING.
.THURSDAY...THE THREAT FOR LOCALLY HEAVY RAIN CONTINUES. DISTURBANCE
MOVING INTO THE MIDWEST WILL STRENGTHEN HIGH PRESSURE OVER THE
NORTHERN PLAINS. THE STRENGTHENING ANTICYCLONE WILL PUSH A COLD
FRONT THROUGH THE PLAINS...INCREASING THE EASTERLY FLOW AND MOISTURE
FLUX INTO THE REGION. THE PLUME OF MIDDLE AND UPPER MOISTURE WILL
ALSO CONTINUE OVER THE REGION EAST OF THE UPPER LOW OVER THE GREAT
BASIN. MODELS CONTINUE TO GENERATE WIDESPREAD SIGNIFICANT
PRECIPITATION OVER THE REGION THURSDAY..ESPECIALLY OVER THE EASTERN
MOUNTAINS AND PLAINS. SUSPECT A WEAK DISTURBANCE IS NORTHEASTWARD
INTO COLORADO. ISSUED A FLASH FLOOD WATCH FOR THURSDAY FOR THE
WALDO CANYON AND BLACK FOREST BURN SCARS. THERE WAS SOME MINOR
FLOODING OVER WALDO CANYON BURN SCAR TODAY AND THE STORMS ON
THURSDAY COULD BE STRONGER. FURTHER WEST...ANTICIPATE MORE COVERAGE
OF STORMS THAN WEDNESDAY AS THE AMOUNT OF MIDDLE AND UPPER LEVEL
MOISTURE INCREASES. --PGW--
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM MDT WED SEP 11 2013
...HEAVY RAIN POSSIBLE THURSDAY NIGHT...
THURSDAY NIGHT-FRIDAY...MODELS CONTINUE TO INDICATE A VERY WET
PERIOD AS WEAKENING UPPER LOW ACROSS WESTERN UTAH IS SLOWLY KICKED
OUT INTO THE NORTHERN ROCKIES BY EASTERN PACIFIC ENERGY DROPPING OUT
OF WESTERN BC AND INTO THE NORTHERN TIER OF STATES. THIS ENHANCES
MOIST LOW LEVEL UPSLOPE FLOW ACROSS THE EASTERN MTS THURSDAY NIGHT
AND ALONG WITH INCREASED UVV FROM ASSOCIATED JET TRANSLATING ACROSS
THE ROCKIES AND THE ABUNDANT ATMOSPHERIC MOISTURE STILL IN
PLACE...WILL SUPPORT THE LOCALLY HEAVY RAINFALL ACROSS THE AREA
THURSDAY NIGHT. LATEST MODELS CONTINUE TO PEG EASTERN COLORADO AND
IN PARTICULAR THE PIKES PEAK REGION...WHERE LOW LEVEL UPSLOPE WILL
BE MAXIMIZED...FOR HEAVY RAIN THURSDAY NIGHT AND FRIDAY WITH HPC
DAY 2 QPF TOTAL INDICATING 1-2 INCHES ACROSS SOUTHEASTERN COLORADO
WITH A BULLSEYE OF 1.76 INCHES ACROSS THE PALMER DVD AND 1.96
INCHES OVER KIOWA COUNTY. WITH THAT SAID...HAVE KEPT HIGH POPS
INTACT ACROSS THE AREA THURSDAY NIGHT AND FRIDAY...WITH AN
INCREASED CONCERN FOR FLASH FLOODING THURSDAY NIGHT...ESPECIALLY
FOR THE WALDO CANYON AND BLACK FORECAST BURN SCARS.
FRIDAY NIGHT-SUNDAY NIGHT...FLOW ALOFT BECOMES WEAK WESTERLY WITH
MONSOONAL PLUME DECREASING THROUGH SUNDAY...AS THE NORTHERN TIER
SYSTEM CONTINUES TO DROP SOUTH AND EAST ACROSS THE UPPER MIDWEST.
STILL ENOUGH MOISTURE IN PLACE FOR SCATTERED SHOWERS AND STORMS
ACROSS THE AREA SATURDAY...WITH LOCALLY HEAVY RAINFALL STILL A
THREAT DUE TO THE WEAK STEERING FLOW ALOFT. PASSING NORTHERN TIER
SYSTEM SENDS A WEAK BACKDOOR COLD FRONT ACROSS THE EASTERN PLAINS
SATURDAY NIGHT WITH MOIST EASTERLY UPSLOPE FLOW HELPING TO
INCREASE PRECIPITATION CHANCES ACROSS THE EASTERN MTS AND
IMMEDIATE ADJACENT PLAINS SUNDAY AFTERNOON AND EVENING.
MONDAY-WEDNESDAY...MODELS CONTINUE TO INDICATE A WARMING AND DRYING
TREND FOR EARLY NEXT WEEK AS A BROAD UPPER TROUGH SETS UP ACROSS THE
PAC NW COAST...KEEPING MODERATE WEST TO SOUTHWEST FLOW ALOFT ACROSS
THE REGION. THIS WILL ALLOW FOR TEMPERATURES TO WARM BACK TO
GENERALLY ABOVE SEASONAL AVERAGES. LATEST EC INDICATES ANOTHER
POSSIBLE BACKDOOR COLD FRONT MOVING ACROSS THE EASTERN PLAINS ON
WEDNESDAY WITH THE GFS BRINGING THE FRONT ACROSS THURSDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 352 PM MDT WED SEP 11 2013
KCOS AND KPUB...NEXT BATCH OF STORMS IS MOVING NORTHWARD AND WILL
AFFECT KCOS AND KPUB DURING THE LATER AFTERNOON AND EARLY EVENING.
ANTICIPATE MVFR CEILINGS OVERNIGHT WITH ABUNDANT LOW LEVEL MOISTURE
REMAINING. SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP BY LATE
MORNING AS A DISTURBANCE MOVES INTO THE REGION. ATMOSPHERE REMAINS
MOIST AND THERE IS THE THREAT FOR HEAVY RAIN.
KALS...SOME SHOWERS MAY CONTINUE THROUGH MID EVENING. ANTICIPATE
MVFR CEILINGS OVERNIGHT WITH LOW LEVEL MOISTURE REMAINING IN THE SAN
LUIS VALLEY. SHOWERS AND THUNDERSTORMS WILL DEVELOP BY LATE MORNING
AS A DISTURBANCE MOVES INTO THE REGION. --PGW--
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR COZ081-084-085.
FLASH FLOOD WATCH FROM THURSDAY AFTERNOON THROUGH THURSDAY
EVENING FOR COZ081-084-085.
&&
$$
SHORT TERM...PGW
LONG TERM...MW
AVIATION...PGW
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
309 PM MDT WED SEP 11 2013
.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 309 PM MDT WED SEP 11 2013
CURRENT WATER VAPOR IMAGERY SHOWS PLENTY OF DRY AIR MOVING INTO
THE CWA THIS AFTERNOON BUT THIS DRY AIR RESIDES ABOVE 500MB OR
ABOUT 18K FEET. BELOW THAT LEVEL...RESIDUAL MOISTURE EXISTS. THE
LOW PRESSURE TO OUR WEST CONTINUES TO REMAIN FAIRLY STATIONARY AS
SHORT WAVES ROTATE AROUND IT. THE LAST WAVE IS NOW CAUSING
WIDESPREAD SHOWERS AND SOME ISOLATED THUNDERSTORMS MAINLY NORTH OF
I-70. THE STORMS THAT HAVE FORMED HAVE BEEN FAIRLY SLOW MOVERS
ALLOWING HEAVY RAIN TO FALL ON ALREADY SATURATED GROUND...THUS
SOME FLOOD ADVISORIES HAVE BEEN ISSUED. VIS SATELLITE SHOWS PLENTY
OF CONVECTION AROUND THE AREA OF LOW PRESSURE OVER AZ AND WRN UT
BUT NOT MUCH IN THE DRY SLOT THAT HAS FORMED THIS AFTN. HRRR AND
RAP BOTH INDICATING NOT MUCH DEVELOPMENT IN THE 4 CORNERS REGION
EVEN WITH SOME WEAK UPPER LEVEL SUPPORT INCREASING TOWARD THE
EVENING HOURS. WILL KEEP ISOLD TO SCTD SHOWERS AND STORMS IN
FORECAST THOUGH AS ANY WEAK WAVE MAY ALLOW SOME PRECIP TO KICK
OFF. IN THAT REGARD...FLASH FLOOD WATCH WILL ALSO CONTINUE THROUGH
9PM THIS EVENING. OVERNIGHT...EXPECT DRYING TO CONTINUE THOUGH A
STRAY SHOWER OR STORM IS POSSIBLE.
BY TOMORROW...THE LOW PRESSURE WILL HAVE MOVED SLIGHTLY NORTH WHILE
THE PLUME OF MOISTURE WILL HAVE SHIFTED EAST TO THE FRONT RANGE. A
DOWNTICK IN PRECIP IS EXPECTED THOUGH AGAIN...RESIDUAL MOISTURE IN
THE LOWER LEVELS WILL ALLOW SOME SCTD SHOWERS AND STORMS TO FORM.
EXPECT A MIX OF SUN AND CLOUDS WITH TEMPERATURES SLOWLY WARMING UP
AFTER THE LAST FEW MUCH COOLER THAN AVERAGE DAYS. NOT MUCH CHANGE
OVERNIGHT WITH A FEW SHOWERS CONTINUING AS THE LOW CONTINUES TO
SPIN OVER ERN NV/WRN UT.
&&
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 309 PM MDT WED SEP 11 2013
UPPER LEVEL TROUGH BEGINS TO PROPAGATE NORTH FRIDAY WITH THE
REMAINING SOUTH END OF THIS TROUGH FLATTENING OVERNIGHT INTO
SATURDAY. MIDRANGE MODELS AGREE ON 580 DM HEIGHT CONTOUR
DIMINISHING IN SIZE SATURDAY AS IT MOVES NORTH...DECREASING THE
FORCING NEEDED FOR STRATIFORM RAIN. AVAILABLE MOISTURE STILL
REMAINS...HINTING AT SCATTERED TO NUMEROUS SHOWER AND THUNDERSTORM
ACTIVITY THROUGHOUT THE WEEKEND BUT BEING MORE DIURNALLY DRIVEN. WITH
THE UPPER LEVEL JET PUSHING EAST AS THE UPPER LEVEL TROUGH MOVES
TO THE NORTH AND EAST...LACK OF DIVERGENCE ALOFT WILL LIKELY KEEP
SHOWERS AND THUNDERSTORMS FROM BEING WIDESPREAD EVEN WITH PWATS
STILL BETWEEN 0.8 AND 1.0 INCH.
SLIGHT DISCREPANCY BETWEEN THE GFS AND ECMWF BY SATURDAY NIGHT ON
THE LOCATION OF REMAINING TROUGH OVER THE GREAT BASIN DUE TO
TIMING OF AN UPPER LEVEL PACIFIC NORTHWEST LOW PRESSURE SYSTEM PUSHING
THE REMAINING ENERGY EASTWARD. THIS PACIFIC NW FEATURE MOVING EAST
ACROSS THE INTERMOUNTAIN WEST IS PROGGED TO TURN THE FLOW FAIRLY
ZONAL EARLY NEXT WEEK WITH DRIER AIR FROM THE WEST DECREASING THE
THREAT OF SHOWERS EARLY NEXT WEEK. OVERCAST SKIES ALL DAY LONG
SHOULD CEASE SUNDAY...WHICH WILL ALLOW A CHANGE TO SCATTERED CONVECTIVE
PRECIPITATION AND POTENTIALLY HEAVY RAIN IN SHORT AMOUNTS OF TIME.
COUPLE DIFFERENT RESULTS MIDWEEK ON TIMING AND IMPACTS FROM THIS
LARGE UPPER LEVEL TROUGH PUSHING INTO WESTERN US. DEPENDING ON THE
AMPLIFICATION OF THIS TROUGH...STRONG SOUTHWEST FLOW AHEAD OF A
MODERATE COLD FRONT MAY BE THE OVERRIDING FEATURE (12Z GFS
SOLUTION) OR THE VERY NORTHERN PARTS OF THE CWA WILL BE AFFECTED
BY A SMALLER SWATH OF TROUGHINESS (00Z ECMWF SOLUTION) WHILE MOST
OF THE CWA REMAINS RELATIVELY DRY AND SEASONABLY WARM. THE LATTER
SOLUTION IS FAVORED AT THIS TIME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 309 PM MDT WED SEP 11 2013
PLENTY OF CLOUDS...SHOWERS AND EVEN A FEW STORMS CAN BE FOUND
ACROSS THE REGION THIS AFTERNOON. EVEN SO...MAINLY VFR CONDITIONS
ARE BEING REPORTED ACROSS THE REGION. UNDER HEAVIER SHOWERS OCCNL
MVFR WILL OCCUR DUE TO MOSTLY LOW VIS WITH CIGS HOVERING AROUND 8K
TO 10K FEET. ALL TAF SITES HAVE SOME CHANCES TO SEE SOME
RAINSHOWERS OR LIGHT RAIN THROUGH THE EVENING HOURS. CONDITIONS
SHOULD IMPROVE AFTER 06Z THOUGH A FEW STRAY SHOWERS MAY PERSIST.
EXPECT SIMILAR CONDITIONS TOMORROW AFTER 18Z THOUGH COVERAGE
SHOULD BE SOMEWHAT LESS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR COZ003-017-020.
UT...FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR UTZ022-025-
027>029.
&&
$$
SHORT TERM...TGR
LONG TERM...JAM
AVIATION...TGR
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1159 AM MDT WED SEP 11 2013
.UPDATE...
ISSUED AT 925 AM MDT WED SEP 11 2013
FIRST BATCH OF LIGHT TO MODERATE SHOWERS OVER THE WALDO CANYON
BURN SCAR HAS FILLED STREAMS TO NEAR BANK FULL WITH SOME MINOR
FLOODING. WITH CONTINUED MOIST SOUTHERLY FLOW..DECIDED TO ISSUE A
FLASH FLOOD WATCH FOR THE WALDO CANYON AND BLACK FOREST BURN SCARS
AS ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AND
THIS EVENING.
RADAR SHOWS ONE SMALL ROTATION NEAR PUEBLO WEST. CONVECTION IS
DEVELOPING IN CENTRAL NEW MEXICO IN THE DRY SLOT...AND THIS
CONVECTION IS MOVING NORTH. SOME SHORT RANGE MODELS SUGGEST THESE
DISTURBANCES WILL BE STRONG ENOUGH DEVELOP SOME CONVECTION DURING
THE DAY. WALDO CANYON...IN PARTICULAR...APPEARS TO BE PRIMED FOR
SOME FLASH FLOODING IF HEAVIER RAIN PASSES OVER THE BURN SCAR.
--PGW--
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM MDT WED SEP 11 2013
THE UPR LOW IS EXPECTED TO BE CENTERED OVR THE SWRN CORNER OF UT
TODAY AND MAYBE MOVING SLIGHTLY NORTHWARD OVERNIGHT. MODELS ARE
SHOWING THE PLUME OF UPR MSTR SHIFTING EASTWARD THRU THE DAY AND
MAINLY BEING OVR THE EASTERN PORTIONS OF THE FORECAST AREA THIS
AFTERNOON...AND THEN BEING OVR THE FAR SERN PLAINS TONIGHT. WV
IMAGERY THIS MORNING SHOWING THE DRIER AIR WORKING ITS WAY INTO SWRN
CO. CURRENT RADAR LOOP SHOWING SOME ISOLD TO SCT ECHOES OVR THE SAN
LUIS VALLEY AND ALONG THE CONTDVD...WITH MORE PCPN OVR ERN AREAS AND
ADDITIONAL PCPN WORKING ITS WAY NORTHWARD FROM EASTERN NM.
IN GENERAL...THE HRRR SHOWS MAINLY ISOLD TO SCT POPS OVR THE SAN
LUIS VALLEY AND ALONG THE CONTDVD TODAY...WITH SCT OR HIGHER POPS
FROM THE ERN MTS TO THE ERN BORDER. THE WRF IS SIMILAR...ALTHOUGH IT
SHOWS HIGHER POPS OVR THE HIGHER TRRN IN THE MORNING HOURS...AND
THEN DECREASES THE PCPN CHANCES FOR THE AFTERNOON HOURS ALONG THE
CONTDVD AND SAN LUIS VALLEY AS THE DRIER AIR MOVES SPREADS OVR THE
AREA. THE NAM LOOKS OVERDONE AGAIN IN TERMS OF PCPN ACCUMULATION OVR
THE ERN MTS AND I-25 CORRIDOR FOR THE MORNING HOURS. BASED ON THE
WRF AND HRRR...PCPN OVR THE BURN SCARS TODAY SHOULD MOSTLY BE HIT
OR MISS AND NOT A PROLONGED EVENT...WL NOT ISSUE A FLASH FLOODING
HIGHLIGHT. HOWEVER THERE IS STILL THE CHANCE FOR LOCALLY HEAVY
RAIN AND THE STEERING FLOW TODAY IS EXPECTED TO BE ONLY AROUND
10-15 KTS OVR THE ERN MTS AND I-25 CORRIDOR...THUS FLASH FLOODING
CANNOT BE RULED OUT IF A STRONG SLOW MOVING STORM WERE TO MOVE OVR
AREA BURN SCARS. TEMPS OVR THE MTN PEAKS WL AGAIN BE COLD ENOUGH
FOR SOME SNOW TO OCCUR WITH SOME LIGHT ACCUMULATIONS.
FOR TONIGHT...ALL MODELS BRING DRIER CONDITIONS TO THE WESTERN HALF
OF THE FORECAST AREA...WITH SOME PCPN CONTINUING THRU THE NIGHT OVR
PORTIONS OF THE ERN PLAINS...ESPECIALLY THE FAR EASTERN AREAS AS A
COUPLE DISTURBANCES MOVES ACRS THAT AREA.
|
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 333 AM MDT WED SEP 11 2013
...WET THROUGH SUNDAY...
...DRYING OUT NEXT WEEK...
WET FORECAST REMAINS ON TRACK. WETTEST PERIOD STILL LOOKS TO BE THU
INTO FRI OF THIS WEEK...WHEN THE UPPER LOW IS MOVING THROUGH WRN UT
AND ERN NV...AND UPSLOPE WILL BE MAXIMIZED OVER THE ERN CO PLAINS.
THE ERN MTS...IN PARTICULAR THE ERN SLOPES...WILL LIKELY SEE THE
MOST QPF FROM THIS EVENT. THE NAM12 IS STILL PROGGING 2-4 INCHES OF
LIQUID FOR THE SRN FRONT RANGE AND PIKES PEAK REGION. PRETTY MUCH
THE ENTIRE AREA SHOULD SEE AN INCH OF RAIN OR BETTER OVER THE NEXT
SEVERAL DAYS. THE EXCEPTIONS COULD BE THE SAN LUIS VALLEY AND
PORTIONS OF THE ARKANSAS CANYON...WHICH COULD BE SHELTERED SOMEWHAT
WITH THESE SPOTS NOT AS CONDUCIVE TO UPSLOPE PRECIP. PORTIONS OF THE
FAR ERN PLAINS MIGHT ALSO SEE A BIT MORE SPOTTY TOTALS...SINCE THE
PRECIP THERE WILL BE A BIT MORE DEPENDENT ON WHERE CONVECTION SETS
UP. THE HIGHEST AMTS SHOULD BE OVR THE SRN SANGRES...RATON
MESA...AND PALMER DVD AND PIKES PEAK AREA. BURN SCARS IN THIS AREA
WILL BE THE MAIN CONCERN THROUGH THE WEEKEND.
TEMPS SHOULD STAY ON THE COOL SIDE...IN THE 60S AND 70S...THRU
FRIDAY...THEN REBOUND A BIT ON SATURDAY BEFORE ANOTHER FRONT MOVES
THROUGH ON SUN AND KNOCKS THINGS DOWN BELOW AVG AGAIN. POPS WILL
ALSO INCREASE AGAIN ON SUNDAY AS THE NEXT FRONT ARRIVES. SNOW LEVELS
REMAIN RELATIVELY HIGH THROUGH THE END OF THE WEEK...BUT AS
MENTIONED PREVIOUSLY THE HIGHEST ELEVS ABOVE 13K FT OR SO WILL SEE
SOME ACCUMULATING SNOW...PERHAPS QUITE A BIT FOR THE HIGHEST SUMMITS.
BY THE WEEKEND...SNOW LEVELS SHOULD DROP TO AS LOW AS 12K FEET...AND
THIS COULD GIVE THE ERN MTS A GOOD SHOT OF SNOW BY THE END OF THE
WEEKEND.
NEXT WEEK...THE PATTERN WILL BE DOMINATED BY A PROGRESSIVE UPPER LOW
MOVING OUT OF THE PACNW TUE-WED...AND THEN QUICKLY THROUGH THE NRN
ROCKIES ON THU. MOST OF OUR AREA WILL BE TO THE SOUTH OF THE MAIN
CIRCULATION...SO THE PLAINS WILL LIKELY STAY MAINLY DRY AND PERHAPS
A BIT BREEZY. THE MTS COULD SEE SOME OROGRAPHIC PRECIP...BUT MAY SEE
MORE WIND THAN RAIN/SNOW UNLESS THE LOW TRACKS A BIT FARTHER S THAN
THE MODELS CURRENTLY INDICATE. TEMPS SHOULD ALSO CLIMB BACK TO ABOVE
AVG FOR THE PLAINS...POSSIBLY REACHING THE MID 80S OR HIGHER BY
WED-THU. ROSE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1151 AM MDT WED SEP 11 2013
CONVECTION OVER NORTHEAST NEW MEXICO IS MOVING NORTHWARD.
ANTICIPATE AN INCREASE IN PRECIPITATION CHANCES AT THE TAF SITES
FROM MID AFTERNOON AND INTO THE EVENING. BUFKIT SOUNDINGS SUGGEST
THERE MAY BE ENOUGH CAPE TO GET SOME THUNDERSTORMS AT THE TAF
SITES. EXPECT A DECREASE IN PRECIPITATION OVERNIGHT...WITH KPUB
AND KCOS CONTINUING TO HAVE MVFR CEILINGS WITH ABUNDANT LOW LEVEL
MOISTURE. BY MID MORNING THURSDAY...ANOTHER SHORTWAVE WILL
APPROACH FROM THE SOUTH WITH AND INCREASE IN PRECIPITATION BY LATE
MORNING. --PGW--
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 PM MDT THIS EVENING FOR COZ081-084-085.
&&
$$
UPDATE...PGW
SHORT TERM...28
LONG TERM...ROSE
AVIATION...PGW
AREA FORECAST DISCUSSION
NWS ALBANY NY
642 PM EDT WED SEP 11 2013
.SYNOPSIS...
OUR REGION WILL REMAIN IN A WARM AND HUMID AIR MASS TONIGHT INTO
THURSDAY...AS A FRONTAL BOUNDARY REMAINS POSITIONED OVER THE UPPER
GREAT LAKES AND SOUTHEAST CANADA. AS THIS FRONT APPROACHES ON
THURSDAY...SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD
ACROSS THE AREA. THE COLD FRONT WILL PASS THROUGH LATE THURSDAY INTO
THURSDAY NIGHT...AND WILL USHER IN A DRIER AND MUCH COOLER AIR MASS
FOR FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 630 PM EDT...VERY MOIST LOW LEVELS REMAIN IN PLACE WITH
DEWPOINTS WELL INTO THE 70S ACROSS VALLEY LOCATIONS. HEAT INDEX
VALUES HAVE DROPPED BELOW THRESHOLDS AS WE HAVE EXPIRED THE HEAT
ADVISORY. NUMEROUS CONVECTIVE CELLS ARE NOW EXPANDING ACROSS MOST
OF EAST CENTRAL NEW YORK WITH NLDN REVEALING VERY IMPRESSIVE FLASH
DENSITY. PWATS ARE QUITE HIGH PER THE SPC HOURLY MESOSCALE WINDOW
AND THE THREAT FOR HEAVY RAINFALL REMAINS. INCREASED POPS AT THIS
TIME FOR MOST OF THE REGION AS SEVERE THUNDERSTORM WATCH REMAINS
IN EFFECT FOR MOST OF THE REGION.
AS OF 400 PM EDT...SEVERE THUNDERSTORM WATCH 521 CONTINUES UNTIL 10
PM FOR MUCH OF THE AREA EXCEPT FOR DUTCHESS/LITCHFIELD. ALSO A HEAT
ADVISORY REMAINS IN EFFECT UNTIL 6 PM FOR FOR THE HUDSON VALLEY FROM
GENERALLY GLENS FALLS SOUTHWARD TO POUGHKEEPSIE...AS WELL AS
LITCHFIELD CT.
A VERY SUMMER-LIKE DAY ACROSS THE AREA WITH A HOT AND HUMID AIR MASS
POSITIONED OVER THE REGION. TEMPERATURES STILL IN THE UPPER 80S TO
LOWER 90S...WITH OPPRESSIVE DEWPOINTS IN THE LOWER TO MID 70S. HEAT
INDEX VALUES ESPECIALLY IN THE HUDSON VALLEY...HAVE CONSISTENTLY
BEEN RUNNING IN THE 100-105 RANGE MUCH OF THE AFTERNOON. OPPRESSIVE
HEAT AND HUMIDITY OF THIS MAGNITUDE HAS NOT BEEN SEEN SINCE THE HEAT
WAVE BACK IN MID-JULY.
THE SUBSTANTIAL HEAT/HUMIDITY HAS RESULTED IN VERY HIGH LEVELS OF
INSTABILITY. THE SPECIAL 18Z SOUNDING FROM ALB INDICATED OVER 4000
J/KG OF SBCAPE! THE ENTIRE AREA IS EXTREMELY UNSTABLE...RANGING FROM
AROUND 3000 NORTH TO 5000 J/KG SOUTH FROM THE SPC RAP HOURLY
MESOSCALE ANALYSIS. THE BEST 0-6 KM SHEAR CONTINUES TO BE LOCATED
ACROSS NORTHERN PORTIONS OF THE AREA...GENERALLY IN THE 25-35 KT
RANGE...WITH WEAKER MAGNITUDE SOUTH. HOWEVER...DESPITE THE WEAKER
SHEAR FROM AROUND THE CAPITAL REGION SOUTHWARD...THE LARGE MAGNITUDE
OF CAPE WITH STEEP 850-500 MB LAPSE RATES OF OVER 7.0C/KM WILL STILL
RESULT IN A MULTICELL CONVECTIVE MODE WITH LARGE HAIL/DAMAGING WINDS
THE MAIN THREATS.
CONVECTION HAS BEEN INCREASING SUBSTANTIALLY IN COVERAGE ACROSS
SOUTH CENTRAL NY AND CENTRAL PA...AND IS EXPECTED TO SPREAD
NORTHEASTWARD INTO MUCH OF OUR AREA. STILL COME QUESTION AS TO THE
EVENTUAL COVERAGE...SO WILL MENTION SCATTERED COVERAGE FOR NOW. A
FEW CELLS HAVE ALREADY DEVELOPED ACROSS THE HIGHER TERRAIN OF THE
ADIRONDACKS/CATSKILLS. DEPENDING ON EVENTUAL CONVECTIVE
TRENDS...DUTCHESS/LITCHFIELD MAY NEED TO BE ADDED TO THE SEVERE
THUNDERSTORM WATCH LATER ON.
CONVECTION SHOULD START TO DECREASE IN INTENSITY AND EVENTUALLY
DIMINISH IN COVERAGE LATER THIS EVENING. WILL LOWER POPS TO MAINLY
SLIGHT CHANCE AFTER MIDNIGHT...WITH NO DISCERNIBLE FORCING
MECHANISMS AROUND. IT WILL BE ANOTHER WARM AND MUGGY NIGHT WITH LOWS
ONLY IN THE 65-70 RANGE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY LOOKS TO BE ANOTHER ACTIVE DAY ACROSS THE AREA...AS A COLD
FRONT AND UPPER LEVEL TROUGH APPROACH FROM THE GREAT LAKES. HIGH
LEVELS OF MOISTURE WILL REMAIN IN PLACE AHEAD OF THE
FRONT/TROUGH...WITH PWATS EXPECTED TO BE OVER 1.5 INCHES WHICH IS
BETWEEN 1 TO 2 STDEV ABOVE NORMAL FOR MID SEPTEMBER. LARGE SCALE
ASCENT WILL ALSO BE PRESENT...WITH SURFACE CONVERGENCE AHEAD OF AND
ALONG THE COLD FRONT AND UPPER LEVEL DYNAMICS ASSOCIATED WITH THE
TROUGH. SO THERE IS A HIGH PROBABILITY OF WIDESPREAD SHOWERS AND
THUNDERSTORMS...STARTING FROM MAINLY LATE MORNING ACROSS WESTERN
AREAS AND SHIFTING EASTWARD DURING THE AFTERNOON. WILL MENTION
LIKELY TO CATEGORICAL POPS FOR THE ENTIRE AREA.
WITH REGARDS TO THE POTENTIAL FOR SEVERE STORMS AGAIN...THERE IS
SOME QUESTION AS TO HOW MUCH INSTABILITY CAN BUILD AHEAD OF THE COLD
FRONT. THERE COULD BE QUITE A BIT OF CLOUD COVER TO START TO THE
DAY...BUT EXPECTED AT LEAST SOME BREAKS OF SUNSHINE...ESPECIALLY
FROM THE CAPITAL DISTRICT SOUTH AND EAST WHERE IT WILL TAKE LONGER
FOR THE FRONT TO APPROACH. FARTHER NORTH AND WEST OVER THE
ADIRONDACKS...THERE IS A SMALLER TIME WINDOW FOR BREAKS OF SUN AND
RESULTING INSTABILITY BUILDUP. SO EXPECTING THE MAIN THREAT AREA TO
BE FROM THE MOHAWK AND HUDSON VALLEYS SOUTH AND EAST. MAGNITUDE OF
CAPE IS NOT EXPECTED TO BE AS STRONG AS WEDNESDAY AND MID-LEVEL
LAPSE RATES ARE FORECAST TO BE WEAKER AND GENERALLY 6.0C/KM OR LESS.
THE DEEP LAYER SHEAR IS EXPECTED TO BE STRONGEST OVER THE NORTHERN
HALF OF THE AREA...AROUND 30-35 KT. SO THE MAIN THREATS ARE EXPECTED
TO BE DAMAGING WINDS FROM WET MICROBURSTS AND LOCALLY HEAVY
RAINFALL. ISOLATED FLASH FLOODING IS POSSIBLE...BUT SYNOPTIC SCALE
PARAMETERS DO NOT FAVOR A WIDESPREAD FLASH FLOOD EVENT.
MODEL GUIDANCE IN GENERAL AGREEMENT WITH SHOWING SHOWERS AND
T-STORMS LINGERING THROUGH MUCH OF THE EVENING...ESPECIALLY FROM THE
HUDSON VALLEY EASTWARD...AS IT WILL TAKE SOME TIME FOR THE COLD
FRONT TO CLEAR THE AREA. ANY SEVERE THREAT SHOULD DIMINISH AFTER
DARK WITH LOSS OF INSTABILITY. THE WIDESPREAD CONVECTION WILL TAPER
OFF TO SCATTERED SHOWERS OVERNIGHT.
FRIDAY LOOKS TO BE MUCH COOLER AND BREEZY BEHIND THE COLD FRONT.
TEMPERATURES WILL ACTUALLY BE BELOW NORMAL AFTER BEING WELL ABOVE
NORMAL FOR MUCH OF THE WEEK. THERE WILL LIKELY BE MORE CLOUDS THAN
SUNSHINE...WITH ISOLATED TO SCATTERED SHOWERS...AS THE UPPER TROUGH
AXIS MOVES OVERHEAD. THE BEST CHANCE FOR ANY MEASURABLE PRECIP WILL
BE OVER THE HIGHER TERRAIN. GRADUAL DRYING AND CLEARING EXPECTED
FRIDAY NIGHT AS THE UPPER TROUGH AXIS SHIFTS EAST OF THE AREA AND
HIGH PRESSURE BUILDS EASTWARD ACROSS THE GREAT LAKES. DRY AND COOL
WEATHER IN STORE FOR SATURDAY WITH HIGH PRESSURE BUILDING IN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THIS WILL BE A RELATIVELY DRY PERIOD WITH THE ONLY FEATURE THAT MAY
BRING US A MAINLY SLIGHT CHANCE OF SHOWERS BEING A COLD FRONTAL
PASSAGE SUNDAY NIGHT. TEMPERATURES WILL BE SEASONABLY COOL
THROUGHOUT THE WEEK...WITH HIGHS RANGING FROM AROUND 60 DEGREES IN
THE HIGH PEAKS...TO AROUND 70 IN THE VALLEYS. BEHIND THE COLD
FRONT...HIGHS WILL RANGE FROM THE LOW AND MID 50S IN THE HIGHER
ELEVATIONS...TO THE MID AND UPPER 60S IN THE LOWER ELEVATIONS. BY
WEDNESDAY...READINGS WILL HAVE BOUNCED BACK TO HIGHS FROM AROUND 60
DEGREES IN THE HIGH PEAKS...TO AROUND 70 IN THE VALLEYS.
LOWS SATURDAY NIGHT WILL RANGE FROM THE LOWER AND MID 30S IN THE
HIGHER ELEVATIONS...TO MAINLY THE LOWER 40S DOWN THE HUDSON VALLEY
AND ACROSS THE SOUTHERN TIER. LOWS SUNDAY NIGHT WILL RANGE FROM THE
LOWER 40S TO LOWER 50S...BACKING OFF AGAIN MONDAY NIGHT TO LOWS
SIMILAR TO THOSE OF SATURDAY NIGHT. TUESDAY NIGHT LOWS WILL AVERAGE
SLIGHTLY MILDER. NORMAL HIGHS IN ALBANY FOR THIS PERIOD ARE IN THE
LOWER 70S...WITH THE NORMAL LOWS IN THE LOWER 50S.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
CLEAR SKIES ARE CURRENTLY IN PLACE ACROSS THE REGION WITH FEW-SCT
CU STARTING TO DEVELOP TO THE WEST OF THE TERMINALS OVER THE HIGH
TERRAIN OF THE ADIRONDACKS AND CATSKILLS. VFR CONDITIONS WILL BE
IN PLACE THROUGH THE REMAINDER OF THE EARLY TO MID AFTN HOURS.
BY THE LATE AFTN AND INTO THE EVENING...SCT THUNDERSTORMS DEVELOPING
OVER PA AND WESTERN/CENTRAL NY WILL SPREAD EASTWARD TOWARDS EASTERN
NY AND WESTERN NEW ENGLAND. WILL INCLUDE A VCSH AND A TEMPO FOR A
TSRA AT KGFL/KPSF/KALB. KPOU SHOULD BE FAR ENOUGH SOUTH TO AVOID THE
MAJORITY OF THE TSTORM ACTIVITY TODAY. FLYING CONDITIONS CAN BRIEFLY
DROP TO MVFR AND PERHAPS EVEN IFR WITHIN ANY TSTM AS IT PASSES OVER
THE REGION WITH GUSTY WESTERLY WINDS AS WELL.
SHRA/TSRA WILL DISSIPATE AND/OR MOVE AWAY FROM THE REGION BY THE
LATE EVENING. WITH THE HIGH LOW LEVEL MOISTURE IN PLACE...SOME
MIST/FOG WILL DEVELOP TONIGHT...ESP AT THOSE SITES THAT SEE RAINFALL
LATER THIS AFTN OR THIS EVENING. KGFL/KPSF WILL BE MOST SUSCEPTIBLE
TO DROPPING TO IFR VSBY DUE TO LOCAL TERRAIN EFFECTS...WITH AT LEAST
MVFR AT THE OTHER SITES AS WELL.
MORE SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON THURSDAY MORNING INTO
AFTN AS A COLD FRONT APPROACHES. FOR NOW...WILL INCLUDE A VCSH AND
SHOW INCREASINGLY LOWER CIGS FOR THE MORNING HOURS.
OUTLOOK...
THURSDAY TO THURSDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY
SHRA...TSRA.
FRIDAY: LOW OPERATIONAL IMPACT. BREEZY. SLIGHT CHANCE OF SHRA.
FRIDAY NIGHT TO MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER ISSUES ARE EXPECTED AT THIS TIME. SCATTERED
THUNDERSTORMS WITH DOWNPOURS ARE EXPECTED INTO THIS EVENING BEFORE
WEAKENING. A STRONG COLD FRONT...ACCOMPANIED BY WIDESPREAD SHOWERS
AND THUNDERSTORMS WITH HEAVY RAIN...WILL MOVE ACROSS THE REGION
THURSDAY USHERING IN A MUCH COOLER AND LESS HUMID AUTUMN AIR MASS
FOR FRIDAY INTO THE WEEKEND.
&&
.HYDROLOGY...
SCATTERED SHOWERS AND THUNDERSTORMS WITH DOWNPOURS...ARE EXPECTED
ACROSS THE HSA DURING THE AFTERNOON AND EVENING HOURS TODAY
ASSOCIATED WITH A PRE FRONTAL TROUGH. MORE WIDESPREAD CONVECTION IS
EXPECTED ON THURSDAY WITH ADDITIONAL DOWNPOURS...ASSOCIATED WITH A
STRONG COLD FRONT DROPPING SOUTHEASTWARD THROUGH OUR REGION LATE
THURSDAY AND THURSDAY NIGHT. DRIER AND MUCH COOLER WEATHER IS
EXPECTED TO END THE WEEK.
WITHIN ANY SHOWERS OR THUNDERSTORMS...THERE WILL BE THE POTENTIAL
FOR MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS
DUE TO HEAVY RAIN FALLING IN A SHORT PERIOD OF TIME THIS AFTERNOON
INTO THIS EVENING. THERE IS EVEN A THREAT OF ISOLATED FLASH FLOODING
WHERE THUNDERSTORMS REPEATEDLY MOVE ACROSS THE SAME AREAS.
THUNDERSTORMS SHOULD DIMINISH LATER THIS EVENING INTO THE OVERNIGHT
HOURS.
THURSDAY INTO THURSDAY EVENING...WITH THE MORE WIDESPREAD SHOWERS
AND THUNDERSTORMS...SOME AREAS MAY RECEIVE AROUND 1 TO 2 INCHES OF
RAIN. AGAIN...MAINLY MINOR FLOODING OF POOR DRAINAGE...URBAN...AND
LOW LYING AREAS IS EXPECTED WITH ISOLATED FLASH FLOODING. WITHIN
BANK RISES WILL OCCUR ON SOME MAIN STEM RIVERS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...JPV
NEAR TERM...BGM/JPV
SHORT TERM...JPV
LONG TERM...ELH
AVIATION...FRUGIS
FIRE WEATHER...JPV
HYDROLOGY...JPV
AREA FORECAST DISCUSSION
NWS ALBANY NY
424 PM EDT WED SEP 11 2013
.SYNOPSIS...
OUR REGION WILL REMAIN IN A WARM AND HUMID AIR MASS TONIGHT INTO
THURSDAY...AS A FRONTAL BOUNDARY REMAINS POSITIONED OVER THE UPPER
GREAT LAKES AND SOUTHEAST CANADA. AS THIS FRONT APPROACHES ON
THURSDAY...SHOWERS AND THUNDERSTORMS WILL BECOME MORE WIDESPREAD
ACROSS THE AREA. THE COLD FRONT WILL PASS THROUGH LATE THURSDAY INTO
THURSDAY NIGHT...AND WILL USHER IN A DRIER AND MUCH COOLER AIR MASS
FOR FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 400 PM EDT...SEVERE THUNDERSTORM WATCH 521 CONTINUES UNTIL 10
PM FOR MUCH OF THE AREA EXCEPT FOR DUTCHESS/LITCHFIELD. ALSO A HEAT
ADVISORY REMAINS IN EFFECT UNTIL 6 PM FOR FOR THE HUDSON VALLEY FROM
GENERALLY GLENS FALLS SOUTHWARD TO POUGHKEEPSIE...AS WELL AS
LITCHFIELD CT.
A VERY SUMMER-LIKE DAY ACROSS THE AREA WITH A HOT AND HUMID AIR MASS
POSITIONED OVER THE REGION. TEMPERATURES STILL IN THE UPPER 80S TO
LOWER 90S...WITH OPPRESSIVE DEWPOINTS IN THE LOWER TO MID 70S. HEAT
INDEX VALUES ESPECIALLY IN THE HUDSON VALLEY...HAVE CONSISTENTLY
BEEN RUNNING IN THE 100-105 RANGE MUCH OF THE AFTERNOON. OPPRESSIVE
HEAT AND HUMIDITY OF THIS MAGNITUDE HAS NOT BEEN SEEN SINCE THE HEAT
WAVE BACK IN MID-JULY.
THE SUBSTANTIAL HEAT/HUMIDITY HAS RESULTED IN VERY HIGH LEVELS OF
INSTABILITY. THE SPECIAL 18Z SOUNDING FROM ALB INDICATED OVER 4000
J/KG OF SBCAPE! THE ENTIRE AREA IS EXTREMELY UNSTABLE...RANGING FROM
AROUND 3000 NORTH TO 5000 J/KG SOUTH FROM THE SPC RAP HOURLY
MESOSCALE ANALYSIS. THE BEST 0-6 KM SHEAR CONTINUES TO BE LOCATED
ACROSS NORTHERN PORTIONS OF THE AREA...GENERALLY IN THE 25-35 KT
RANGE...WITH WEAKER MAGNITUDE SOUTH. HOWEVER...DESPITE THE WEAKER
SHEAR FROM AROUND THE CAPITAL REGION SOUTHWARD...THE LARGE MAGNITUDE
OF CAPE WITH STEEP 850-500 MB LAPSE RATES OF OVER 7.0C/KM WILL STILL
RESULT IN A MULTICELL CONVECTIVE MODE WITH LARGE HAIL/DAMAGING WINDS
THE MAIN THREATS.
CONVECTION HAS BEEN INCREASING SUBSTANTIALLY IN COVERAGE ACROSS
SOUTH CENTRAL NY AND CENTRAL PA...AND IS EXPECTED TO SPREAD
NORTHEASTWARD INTO MUCH OF OUR AREA. STILL COME QUESTION AS TO THE
EVENTUAL COVERAGE...SO WILL MENTION SCATTERED COVERAGE FOR NOW. A
FEW CELLS HAVE ALREADY DEVELOPED ACROSS THE HIGHER TERRAIN OF THE
ADIRONDACKS/CATSKILLS. DEPENDING ON EVENTUAL CONVECTIVE
TRENDS...DUTCHESS/LITCHFIELD MAY NEED TO BE ADDED TO THE SEVERE
THUNDERSTORM WATCH LATER ON.
CONVECTION SHOULD START TO DECREASE IN INTENSITY AND EVENTUALLY
DIMINISH IN COVERAGE LATER THIS EVENING. WILL LOWER POPS TO MAINLY
SLIGHT CHANCE AFTER MIDNIGHT...WITH NO DISCERNIBLE FORCING
MECHANISMS AROUND. IT WILL BE ANOTHER WARM AND MUGGY NIGHT WITH LOWS
ONLY IN THE 65-70 RANGE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY LOOKS TO BE ANOTHER ACTIVE DAY ACROSS THE AREA...AS A COLD
FRONT AND UPPER LEVEL TROUGH APPROACH FROM THE GREAT LAKES. HIGH
LEVELS OF MOISTURE WILL REMAIN IN PLACE AHEAD OF THE
FRONT/TROUGH...WITH PWATS EXPECTED TO BE OVER 1.5 INCHES WHICH IS
BETWEEN 1 TO 2 STDEV ABOVE NORMAL FOR MID SEPTEMBER. LARGE SCALE
ASCENT WILL ALSO BE PRESENT...WITH SURFACE CONVERGENCE AHEAD OF AND
ALONG THE COLD FRONT AND UPPER LEVEL DYNAMICS ASSOCIATED WITH THE
TROUGH. SO THERE IS A HIGH PROBABILITY OF WIDESPREAD SHOWERS AND
THUNDERSTORMS...STARTING FROM MAINLY LATE MORNING ACROSS WESTERN
AREAS AND SHIFTING EASTWARD DURING THE AFTERNOON. WILL MENTION
LIKELY TO CATEGORICAL POPS FOR THE ENTIRE AREA.
WITH REGARDS TO THE POTENTIAL FOR SEVERE STORMS AGAIN...THERE IS
SOME QUESTION AS TO HOW MUCH INSTABILITY CAN BUILD AHEAD OF THE COLD
FRONT. THERE COULD BE QUITE A BIT OF CLOUD COVER TO START TO THE
DAY...BUT EXPECTED AT LEAST SOME BREAKS OF SUNSHINE...ESPECIALLY
FROM THE CAPITAL DISTRICT SOUTH AND EAST WHERE IT WILL TAKE LONGER
FOR THE FRONT TO APPROACH. FARTHER NORTH AND WEST OVER THE
ADIRONDACKS...THERE IS A SMALLER TIME WINDOW FOR BREAKS OF SUN AND
RESULTING INSTABILITY BUILDUP. SO EXPECTING THE MAIN THREAT AREA TO
BE FROM THE MOHAWK AND HUDSON VALLEYS SOUTH AND EAST. MAGNITUDE OF
CAPE IS NOT EXPECTED TO BE AS STRONG AS WEDNESDAY AND MID-LEVEL
LAPSE RATES ARE FORECAST TO BE WEAKER AND GENERALLY 6.0C/KM OR LESS.
THE DEEP LAYER SHEAR IS EXPECTED TO BE STRONGEST OVER THE NORTHERN
HALF OF THE AREA...AROUND 30-35 KT. SO THE MAIN THREATS ARE EXPECTED
TO BE DAMAGING WINDS FROM WET MICROBURSTS AND LOCALLY HEAVY
RAINFALL. ISOLATED FLASH FLOODING IS POSSIBLE...BUT SYNOPTIC SCALE
PARAMETERS DO NOT FAVOR A WIDESPREAD FLASH FLOOD EVENT.
MODEL GUIDANCE IN GENERAL AGREEMENT WITH SHOWING SHOWERS AND
T-STORMS LINGERING THROUGH MUCH OF THE EVENING...ESPECIALLY FROM THE
HUDSON VALLEY EASTWARD...AS IT WILL TAKE SOME TIME FOR THE COLD
FRONT TO CLEAR THE AREA. ANY SEVERE THREAT SHOULD DIMINISH AFTER
DARK WITH LOSS OF INSTABILITY. THE WIDESPREAD CONVECTION WILL TAPER
OFF TO SCATTERED SHOWERS OVERNIGHT.
FRIDAY LOOKS TO BE MUCH COOLER AND BREEZY BEHIND THE COLD FRONT.
TEMPERATURES WILL ACTUALLY BE BELOW NORMAL AFTER BEING WELL ABOVE
NORMAL FOR MUCH OF THE WEEK. THERE WILL LIKELY BE MORE CLOUDS THAN
SUNSHINE...WITH ISOLATED TO SCATTERED SHOWERS...AS THE UPPER TROUGH
AXIS MOVES OVERHEAD. THE BEST CHANCE FOR ANY MEASURABLE PRECIP WILL
BE OVER THE HIGHER TERRAIN. GRADUAL DRYING AND CLEARING EXPECTED
FRIDAY NIGHT AS THE UPPER TROUGH AXIS SHIFTS EAST OF THE AREA AND
HIGH PRESSURE BUILDS EASTWARD ACROSS THE GREAT LAKES. DRY AND COOL
WEATHER IN STORE FOR SATURDAY WITH HIGH PRESSURE BUILDING IN.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THIS WILL BE A RELATIVELY DRY PERIOD WITH THE ONLY FEATURE THAT MAY
BRING US A MAINLY SLIGHT CHANCE OF SHOWERS BEING A COLD FRONTAL
PASSAGE SUNDAY NIGHT. TEMPERATURES WILL BE SEASONABLY COOL
THROUGHOUT THE WEEK...WITH HIGHS RANGING FROM AROUND 60 DEGREES IN
THE HIGH PEAKS...TO AROUND 70 IN THE VALLEYS. BEHIND THE COLD
FRONT...HIGHS WILL RANGE FROM THE LOW AND MID 50S IN THE HIGHER
ELEVATIONS...TO THE MID AND UPPER 60S IN THE LOWER ELEVATIONS. BY
WEDNESDAY...READINGS WILL HAVE BOUNCED BACK TO HIGHS FROM AROUND 60
DEGREES IN THE HIGH PEAKS...TO AROUND 70 IN THE VALLEYS.
LOWS SATURDAY NIGHT WILL RANGE FROM THE LOWER AND MID 30S IN THE
HIGHER ELEVATIONS...TO MAINLY THE LOWER 40S DOWN THE HUDSON VALLEY
AND ACROSS THE SOUTHERN TIER. LOWS SUNDAY NIGHT WILL RANGE FROM THE
LOWER 40S TO LOWER 50S...BACKING OFF AGAIN MONDAY NIGHT TO LOWS
SIMILAR TO THOSE OF SATURDAY NIGHT. TUESDAY NIGHT LOWS WILL AVERAGE
SLIGHTLY MILDER. NORMAL HIGHS IN ALBANY FOR THIS PERIOD ARE IN THE
LOWER 70S...WITH THE NORMAL LOWS IN THE LOWER 50S.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
CLEAR SKIES ARE CURRENTLY IN PLACE ACROSS THE REGION WITH FEW-SCT
CU STARTING TO DEVELOP TO THE WEST OF THE TERMINALS OVER THE HIGH
TERRAIN OF THE ADIRONDACKS AND CATSKILLS. VFR CONDITIONS WILL BE
IN PLACE THROUGH THE REMAINDER OF THE EARLY TO MID AFTN HOURS.
BY THE LATE AFTN AND INTO THE EVENING...SCT THUNDERSTORMS DEVELOPING
OVER PA AND WESTERN/CENTRAL NY WILL SPREAD EASTWARD TOWARDS EASTERN
NY AND WESTERN NEW ENGLAND. WILL INCLUDE A VCSH AND A TEMPO FOR A
TSRA AT KGFL/KPSF/KALB. KPOU SHOULD BE FAR ENOUGH SOUTH TO AVOID THE
MAJORITY OF THE TSTORM ACTIVITY TODAY. FLYING CONDITIONS CAN BRIEFLY
DROP TO MVFR AND PERHAPS EVEN IFR WITHIN ANY TSTM AS IT PASSES OVER
THE REGION WITH GUSTY WESTERLY WINDS AS WELL.
SHRA/TSRA WILL DISSIPATE AND/OR MOVE AWAY FROM THE REGION BY THE
LATE EVENING. WITH THE HIGH LOW LEVEL MOISTURE IN PLACE...SOME
MIST/FOG WILL DEVELOP TONIGHT...ESP AT THOSE SITES THAT SEE RAINFALL
LATER THIS AFTN OR THIS EVENING. KGFL/KPSF WILL BE MOST SUSCEPTIBLE
TO DROPPING TO IFR VSBY DUE TO LOCAL TERRAIN EFFECTS...WITH AT LEAST
MVFR AT THE OTHER SITES AS WELL.
MORE SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON THURSDAY MORNING INTO
AFTN AS A COLD FRONT APPROACHES. FOR NOW...WILL INCLUDE A VCSH AND
SHOW INCREASINGLY LOWER CIGS FOR THE MORNING HOURS.
OUTLOOK...
THURSDAY TO THURSDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY
SHRA...TSRA.
FRIDAY: LOW OPERATIONAL IMPACT. BREEZY. SLIGHT CHANCE OF SHRA.
FRIDAY NIGHT TO MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER ISSUES ARE EXPECTED AT THIS TIME. SCATTERED
THUNDERSTORMS WITH DOWNPOURS ARE EXPECTED INTO THIS EVENING BEFORE
WEAKENING. A STRONG COLD FRONT...ACCOMPANIED BY WIDESPREAD SHOWERS
AND THUNDERSTORMS WITH HEAVY RAIN...WILL MOVE ACROSS THE REGION
THURSDAY USHERING IN A MUCH COOLER AND LESS HUMID AUTUMN AIR MASS
FOR FRIDAY INTO THE WEEKEND.
&&
.HYDROLOGY...
SCATTERED SHOWERS AND THUNDERSTORMS WITH DOWNPOURS...ARE EXPECTED
ACROSS THE HSA DURING THE AFTERNOON AND EVENING HOURS TODAY
ASSOCIATED WITH A PRE FRONTAL TROUGH. MORE WIDESPREAD CONVECTION IS
EXPECTED ON THURSDAY WITH ADDITIONAL DOWNPOURS...ASSOCIATED WITH A
STRONG COLD FRONT DROPPING SOUTHEASTWARD THROUGH OUR REGION LATE
THURSDAY AND THURSDAY NIGHT. DRIER AND MUCH COOLER WEATHER IS
EXPECTED TO END THE WEEK.
WITHIN ANY SHOWERS OR THUNDERSTORMS...THERE WILL BE THE POTENTIAL
FOR MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS
DUE TO HEAVY RAIN FALLING IN A SHORT PERIOD OF TIME THIS AFTERNOON
INTO THIS EVENING. THERE IS EVEN A THREAT OF ISOLATED FLASH FLOODING
WHERE THUNDERSTORMS REPEATEDLY MOVE ACROSS THE SAME AREAS.
THUNDERSTORMS SHOULD DIMINISH LATER THIS EVENING INTO THE OVERNIGHT
HOURS.
THURSDAY INTO THURSDAY EVENING...WITH THE MORE WIDESPREAD SHOWERS
AND THUNDERSTORMS...SOME AREAS MAY RECEIVE AROUND 1 TO 2 INCHES OF
RAIN. AGAIN...MAINLY MINOR FLOODING OF POOR DRAINAGE...URBAN...AND
LOW LYING AREAS IS EXPECTED WITH ISOLATED FLASH FLOODING. WITHIN
BANK RISES WILL OCCUR ON SOME MAIN STEM RIVERS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR CTZ001-013.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ041-049-050-
052-053-059-060-064-065-083-084.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...JPV
NEAR TERM...JPV
SHORT TERM...JPV
LONG TERM...ELH
AVIATION...FRUGIS
FIRE WEATHER...JPV
HYDROLOGY...JPV
AREA FORECAST DISCUSSION
NWS ALBANY NY
118 PM EDT WED SEP 11 2013
.SYNOPSIS...
HAZY...HOT AND HUMID CONDITIONS ARE IN STORE FOR OUR
REGION THIS AFTERNOON WITH A CHANCE FOR A SHOWER OR
THUNDERSTORM...SOME OF WHICH MAY LOCALLY BE SEVERE. A STRONG COLD
FRONT...ACCOMPANIED BY WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN...WILL MOVE ACROSS THE REGION THURSDAY USHERING IN A MUCH
COOLER AND LESS HUMID AUTUMN AIR MASS FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 115 PM EDT...MULTIPLE HAZARDS TO DEAL WITH TODAY. HAD TO
ISSUE A SHORT-FUSE HEAT ADVISORY FOR THE HUDSON VALLEY FROM
GENERALLY GLENS FALLS SOUTHWARD TO POUGHKEEPSIE...AS WELL AS
LITCHFIELD CT. TEMPERATURES HAVE ALREADY WARMED TO THE UPPER 80S
TO LOWER 90S WITH SURFACE DEWPOINTS RUNNING HIGHER THAN EXPECTED
IN THE LOWER TO EVEN MID 70S! HEAT INDICES WILL BE IN THE LOWER
100S IN THE ADVISORY AREA.
WITH REGARDS TO CONVECTIVE POTENTIAL...STILL MAINLY CLEAR/HAZY
SKIES ACROSS MUCH OF THE AREA...ALTHOUGH CU STARTING TO POP UP
OVER THE HIGHER TERRAIN OF THE CATSKILLS/ADIRONDACKS. MORE
WIDESPREAD/AGITATED CU FARTHER SOUTH AND WEST OVER PA AND SW NY
STATE. THIS IS WHERE CONVECTION IS STARTING TO INITIATE AND IS
WHERE THE MESOSCALE MODELS ARE DEPICTING INITIATION. SCATTERED
T-STORMS ARE EXPECTED TO PROGRESS NORTHEASTWARD INTO OUR AREA
MAINLY DURING THE LATE AFTERNOON INTO THE EARLY EVENING HOURS.
EXTREME INSTABILITY IS EXPECTED...AS SEEN IN THE 12Z KALY
SOUNDING AND SPC RAP MESOSCALE ANALYSIS SHOWING AROUND 3000-5000
J/KG OF SBCAPE ACROSS OUR AREA AT THIS HOUR! IN ADDITION...MID
LEVEL LAPSE RATES IN THE 700HPA TO 500HPA LAYER ARE VERY
IMPRESSIVE WITH READINGS AROUND 7.5 C/KM...AS A PIECE OF THE
ELEVATED MIXED LAYER /EML/ THAT PASSED OVER THE AREA YESTERDAY
REMAINS. SBCAPE VALUES WILL EASILY EXCEED 3000-4000 J/KG BY THIS
AFTN AS SURFACE TEMPS WARM INTO THE LOW 90S...WITH DEWPOINTS IN
THE LOW TO MID 70S. 0-6 KM BULK SHEAR IS MAXIMIZED FURTHER NORTH
ACROSS FAR NORTHERN NY AND THE ST. LAWRENCE VALLEY CLOSER TO A SFC
FRONTAL BOUNDARY...WITH 30-40 KTS FOR THE CENTRAL/NORTHERN HALF OF
OUR AREA.
SYNOPTICALLY...THE MAIN SFC FRONTAL BOUNDARY REMAINS WELL NORTH
AND WEST ACROSS SOUTHERN CANADA...THUS THE CONVECTIVE DEVELOPMENT
WOULD LIKELY BE DUE TO TERRAIN FORCING AND PERHAPS A PRE-FRONTAL
TROUGH. WILL CONTINUE MENTION POTENTIAL FOR SEVERE STORMS IN OUR
HWO PRODUCT. DAMAGING WINDS LOOKS TO BE THE PRIMARY THREAT WITH
ANY STORM...BUT CONSIDERING THAT UPDRAFT STRENGTH COULD BE
MAXIMIZED WITH THE STEEP LAPSE RATES AND ROBUST CAPE IN
PLACE...LARGE HAIL IS POSSIBLE AS WELL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
TONIGHT...EXPECT SHOWERS AND THUNDERSTORMS TO BECOME MORE
NUMEROUS OVERNIGHT ESPECIALLY ACROSS NORTHWEST PORTION OF FA AS
COLD FRONT STARTS TO DROP SOUTHEAST TOWARDS SAINT LAWRENCE VALLEY
LATE AT NIGHT. LOWS ARE EXPECTED TO BE IN THE MID 60S TO AROUND 70.
THURSDAY AND THURSDAY NIGHT...LOOKS LIKE THE POTENTIAL FOR VERY
HEAVY RAIN AS SEVERAL WAVES OF LOW PRESSURE TRACK NORTHEAST ALONG
THE COLD FRONT AS IT SLIDES SLOWLY SOUTHEAST THROUGH FA. PWATS MAY
BRIEFLY EXCEED 2 INCHES AND WITH TREMENDOUS THETA-E RIDGE H10-H8
SLICING RIGHT THROUGH CENTER PORTION OF FA THURSDAY AFT BELIEVE
POTENTIAL EXISTS FOR UP TO SEVERAL INCHES OF RAIN. SPC STILL HAS
MUCH OF FA OUTLOOKED SLIGHT RISK AND THIS WILL DEPEND GREATLY ON
HOW MUCH SURFACE HEATING TAKES PLACE. POSSIBILITY EXISTS THAT ONE
OR MORE LINE SEGMENTS MAY DEVELOP WITH CAPES 1500-2500 J/KG AND
BULK SHEAR INCREASING TO 30 TO 40 KTS. EXPECT HIGHS ON THURSDAY
TO RANGE FROM THE MID 70S NORTHWEST TO MID 80S SOUTHEAST WITH LOWS
THURSDAY NIGHT RANGING FROM THE UPPER 40S NORTHWEST TO UPPER 50S
TO AROUND 60 SOUTHEAST.
FRIDAY AND FRIDAY NIGHT...STILL CANNOT RULE OUT A FEW SHOWERS ON
FRIDAY AS UPPER TROUGH AXIS AND ASSOCIATED VORT MAX SWING ACRS FA.
ON FRIDAY NIGHT ANY LINGERING SCATTERED SHOWERS SHOULD BE
CONFINED TO EXTREME NORTHEAST PORTION OF FA AS UPPER TROUGH AXIS
GRADUALLY SLIDES EAST OF FA. EXPECT MUCH COOLER CONDITIONS WITH
HIGHS ON FRIDAY ONLY RANGING FROM THE MID 50S NORTHWEST TO UPPER
60S TO AROUND 70 SOUTHEAST. LOWS FRIDAY NIGHT ARE EXPECTED TO
RANGE FROM THE UPPER 30S NORTHWEST TO MID 40S SOUTHEAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL TROUGH WILL BE LIFTING NORTH OF NY AND NEW ENGLAND TO
OPEN THE WEEKEND. SFC HIGH PRESSURE WILL BE RIDGING IN FROM THE
LOWER GREAT LAKES AND OHIO. NW FLOW WILL DOMINATE ALOFT. COOL AND
BREEZY CONDITIONS ARE EXPECTED ON SATURDAY...AS H850 TEMPS WILL BE
ONLY +3C TO +5C OVER THE FCST AREA BY MID PM. MAX TEMPS WILL RUN
ABOUT 10 DEGREES BELOW NORMAL WITH HIGHS 60-65F IN THE VALLEYS...AND
GENERALLY MID TO U50S OVER THE HILLS AND MTNS.
SATURDAY NIGHT INTO SUNDAY...THE SFC HIGH MOVES OVER NY AND PA...AND
THEN SLIDES SOUTH AND EAST OFF THE NJ COAST. LOW AND MID LEVEL WARM
ADVECTION WILL OCCUR OVER THE REGION. AFTER A COOL START SUNDAY
MORNING WITH MIN TEMPS RUNNING FROM THE MID AND U30S OVER THE
SRN DACKS TO LOWER TO MID 40S OVER THE HUDSON RIVER VALLEY AND NW
CT...A NICE SUNDAY IS EXPECTED. PARTLY TO MOSTLY SUNNY CONDITIONS
WILL PREVAIL WITH TEMPS MAINLY IN THE 60S TO A FEW L70S OVER THE MID
HUDSON VALLEY. ANOTHER LONG-WAVE UPPER LEVEL TROUGH WILL BE MOVING
EASTWARD ACROSS HUDSON BAY. THIS UPPER TROUGH WILL ALLOW A COLD
FRONT TO APPROACH FROM THE GREAT LAKES REGION AND ST LAWRENCE RIVER
VALLEY FOR THE OPENING OF THE WORK AND SCHOOL WEEK.
SUNDAY NIGHT INTO MONDAY...THE MEDIUM RANGE GUIDANCE VARIES SLIGHTLY
ON THE TIMING AND PASSAGE OF THE COLD FRONT. THE WPC GUIDANCE WAS A
GOOD COMPROMISE WITH THE BOUNDARY MOVING THROUGH IN THE LATE MORNING
AND EARLY PM. SOME LAKE MOISTURE MAY BE UTILIZED...BUT THE OVERALL
LOW-LEVEL CONVERGENCE WITH A PRE-FRONTAL SFC TROUGH...AND THE ACTUAL
COLD FRONT LOOKS PRETTY MEAGER. SLIGHT TO LOW CHC POPS WERE USED
SUNDAY NIGHT UNTIL LUNCH-TIME ON MONDAY FROM THE I-90 CORRIDOR
NORTHWARD FOR SHOWERS. LOWS MONDAY MORNING ARE EXPECTED IN THE 40S
TO L50S...WITH HIGHS SIMILAR TO SUNDAY...BUT A SHADE COOLER OVER THE
SRN GREENS AND SRN DACKS.
MONDAY NIGHT INTO TUESDAY...ANOTHER BROAD CANADIAN SFC ANTICYCLONE
WILL BUILD IN ACROSS THE NORTHEAST FROM SE ONTARIO AND THE UPPER
GREAT LAKES REGION. THE SUBSIDENCE FROM THE HIGH WILL YIELD CLEAR
AND COOL CONDITIONS WITH TEMPS STILL RUNNING BELOW NORMAL FOR MID
SEPT.
OVERALL...PCPN AND TEMPS LOOK BELOW NORMAL IN THE LONG TERM.
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/...
CLEAR SKIES ARE CURRENTLY IN PLACE ACROSS THE REGION WITH FEW-SCT
CU STARTING TO DEVELOP TO THE WEST OF THE TERMINALS OVER THE HIGH
TERRAIN OF THE ADIRONDACKS AND CATSKILLS. VFR CONDITIONS WILL BE
IN PLACE THROUGH THE REMAINDER OF THE EARLY TO MID AFTN HOURS.
BY THE LATE AFTN AND INTO THE EVENING...SCT THUNDERSTORMS DEVELOPING
OVER PA AND WESTERN/CENTRAL NY WILL SPREAD EASTWARD TOWARDS EASTERN
NY AND WESTERN NEW ENGLAND. WILL INCLUDE A VCSH AND A TEMPO FOR A
TSRA AT KGFL/KPSF/KALB. KPOU SHOULD BE FAR ENOUGH SOUTH TO AVOID THE
MAJORITY OF THE TSTORM ACTIVITY TODAY. FLYING CONDITIONS CAN BRIEFLY
DROP TO MVFR AND PERHAPS EVEN IFR WITHIN ANY TSTM AS IT PASSES OVER
THE REGION WITH GUSTY WESTERLY WINDS AS WELL.
SHRA/TSRA WILL DISSIPATE AND/OR MOVE AWAY FROM THE REGION BY THE
LATE EVENING. WITH THE HIGH LOW LEVEL MOISTURE IN PLACE...SOME
MIST/FOG WILL DEVELOP TONIGHT...ESP AT THOSE SITES THAT SEE RAINFALL
LATER THIS AFTN OR THIS EVENING. KGFL/KPSF WILL BE MOST SUSCEPTIBLE
TO DROPPING TO IFR VSBY DUE TO LOCAL TERRAIN EFFECTS...WITH AT LEAST
MVFR AT THE OTHER SITES AS WELL.
MORE SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON THURSDAY MORNING INTO
AFTN AS A COLD FRONT APPROACHES. FOR NOW...WILL INCLUDE A VCSH AND
SHOW INCREASINGLY LOWER CIGS FOR THE MORNING HOURS.
OUTLOOK...
THURSDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY TO SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED ISSUES ARE ANTICIPATED OVER THE NEXT
SEVERAL DAYS.
HAZY...HOT AND HUMID CONDITIONS ARE IN STORE FOR OUR REGION TODAY
WITH A CHANCE FOR A SHOWER OR THUNDERSTORM. A STRONG COLD
FRONT...ACCOMPANIED BY WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN...WILL MOVE ACROSS THE REGION THURSDAY USHERING IN A
MUCH COOLER AND LESS HUMID AUTUMN AIR MASS FOR THE REMAINDER OF
THE WEEK.
&&
.HYDROLOGY...
WIDELY SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS...SOME
WITH VERY HEAVY DOWNPOURS...ARE EXPECTED ACROSS THE HSA DURING THE
AFTERNOON AND EVENING HOURS TODAY LIKELY ASSOCIATED WITH A PRE
FRONTAL TROUGH. MORE WIDESPREAD CONVECTION IS EXPECTED LATE
TONIGHT INTO THURSDAY EVENING WITH HEAVY RAINFALL AS ONE OR MORE
WAVES OF LOW PRESSURE ARE EXPECTED TO TRACK NORTHEAST ALONG A
STRONG COLD FRONT WHICH WILL BE DROPPING SOUTHEAST THROUGH OUR
REGION LATE THURSDAY AND THURSDAY NIGHT. DRIER AND COOLER WEATHER
IS EXPECTED TO END THE WEEK
WITHIN ANY SHOWER OR THUNDERSTORM...THERE WILL BE THE POTENTIAL FOR
MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS DUE TO
VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME TODAY THROUGH
THIS EVENING. LATE TONIGHT THROUGH THURSDAY EVENING EXPECT A MORE
WIDESPREAD HEAVY RAIN EVENT WITH SIGNIFICANT RISES OCCURRING ON
SOME MAIN STEM RIVERS WITH UP TO SEVERAL INCHES OF RAIN POSSIBLE.
IN ADDITION FLOODING OF SMALL STREAMS AND CREEKS MAY ALSO OCCUR.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR CTZ001-013.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ041-049-050-
052-053-059-060-064-065-083-084.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/JPV
SHORT TERM...11
LONG TERM...WASULA
AVIATION...FRUGIS
FIRE WEATHER...11
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS ALBANY NY
115 PM EDT WED SEP 11 2013
.SYNOPSIS...
HAZY...HOT AND HUMID CONDITIONS ARE IN STORE FOR OUR
REGION THIS AFTERNOON WITH A CHANCE FOR A SHOWER OR
THUNDERSTORM...SOME OF WHICH MAY LOCALLY BE SEVERE. A STRONG COLD
FRONT...ACCOMPANIED BY WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN...WILL MOVE ACROSS THE REGION THURSDAY USHERING IN A MUCH
COOLER AND LESS HUMID AUTUMN AIR MASS FOR THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 115 PM EDT...MULTIPLE HAZARDS TO DEAL WITH TODAY. HAD TO
ISSUE A SHORT-FUSE HEAT ADVISORY FOR THE HUDSON VALLEY FROM
GENERALLY GLENS FALLS SOUTHWARD TO POUGHKEEPSIE...AS WELL AS
LITCHFIELD CT. TEMPERATURES HAVE ALREADY WARMED TO THE UPPER 80S
TO LOWER 90S WITH SURFACE DEWPOINTS RUNNING HIGHER THAN EXPECTED
IN THE LOWER TO EVEN MID 70S! HEAT INDICES WILL BE IN THE LOWER
100S IN THE ADVISORY AREA.
WITH REGARDS TO CONVECTIVE POTENTIAL...STILL MAINLY CLEAR/HAZY
SKIES ACROSS MUCH OF THE AREA...ALTHOUGH CU STARTING TO POP UP
OVER THE HIGHER TERRAIN OF THE CATSKILLS/ADIRONDACKS. MORE
WIDESPREAD/AGITATED CU FARTHER SOUTH AND WEST OVER PA AND SW NY
STATE. THIS IS WHERE CONVECTION IS STARTING TO INITIATE AND IS
WHERE THE MESOSCALE MODELS ARE DEPICTING INITIATION. SCATTERED
T-STORMS ARE EXPECTED TO PROGRESS NORTHEASTWARD INTO OUR AREA
MAINLY DURING THE LATE AFTERNOON INTO THE EARLY EVENING HOURS.
EXTREME INSTABILITY IS EXPECTED...AS SEEN IN THE 12Z KALY
SOUNDING AND SPC RAP MESOSCALE ANALYSIS SHOWING AROUND 3000-5000
J/KG OF SBCAPE ACROSS OUR AREA AT THIS HOUR! IN ADDITION...MID
LEVEL LAPSE RATES IN THE 700HPA TO 500HPA LAYER ARE VERY
IMPRESSIVE WITH READINGS AROUND 7.5 C/KM...AS A PIECE OF THE
ELEVATED MIXED LAYER /EML/ THAT PASSED OVER THE AREA YESTERDAY
REMAINS. SBCAPE VALUES WILL EASILY EXCEED 3000-4000 J/KG BY THIS
AFTN AS SURFACE TEMPS WARM INTO THE LOW 90S...WITH DEWPOINTS IN
THE LOW TO MID 70S. 0-6 KM BULK SHEAR IS MAXIMIZED FURTHER NORTH
ACROSS FAR NORTHERN NY AND THE ST. LAWRENCE VALLEY CLOSER TO A SFC
FRONTAL BOUNDARY...WITH 30-40 KTS FOR THE CENTRAL/NORTHERN HALF OF
OUR AREA.
SYNOPTICALLY...THE MAIN SFC FRONTAL BOUNDARY REMAINS WELL NORTH
AND WEST ACROSS SOUTHERN CANADA...THUS THE CONVECTIVE DEVELOPMENT
WOULD LIKELY BE DUE TO TERRAIN FORCING AND PERHAPS A PRE-FRONTAL
TROUGH. WILL CONTINUE MENTION POTENTIAL FOR SEVERE STORMS IN OUR
HWO PRODUCT. DAMAGING WINDS LOOKS TO BE THE PRIMARY THREAT WITH
ANY STORM...BUT CONSIDERING THAT UPDRAFT STRENGTH COULD BE
MAXIMIZED WITH THE STEEP LAPSE RATES AND ROBUST CAPE IN
PLACE...LARGE HAIL IS POSSIBLE AS WELL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
TONIGHT...EXPECT SHOWERS AND THUNDERSTORMS TO BECOME MORE
NUMEROUS OVERNIGHT ESPECIALLY ACROSS NORTHWEST PORTION OF FA AS
COLD FRONT STARTS TO DROP SOUTHEAST TOWARDS SAINT LAWRENCE VALLEY
LATE AT NIGHT. LOWS ARE EXPECTED TO BE IN THE MID 60S TO AROUND 70.
THURSDAY AND THURSDAY NIGHT...LOOKS LIKE THE POTENTIAL FOR VERY
HEAVY RAIN AS SEVERAL WAVES OF LOW PRESSURE TRACK NORTHEAST ALONG
THE COLD FRONT AS IT SLIDES SLOWLY SOUTHEAST THROUGH FA. PWATS MAY
BRIEFLY EXCEED 2 INCHES AND WITH TREMENDOUS THETA-E RIDGE H10-H8
SLICING RIGHT THROUGH CENTER PORTION OF FA THURSDAY AFT BELIEVE
POTENTIAL EXISTS FOR UP TO SEVERAL INCHES OF RAIN. SPC STILL HAS
MUCH OF FA OUTLOOKED SLIGHT RISK AND THIS WILL DEPEND GREATLY ON
HOW MUCH SURFACE HEATING TAKES PLACE. POSSIBILITY EXISTS THAT ONE
OR MORE LINE SEGMENTS MAY DEVELOP WITH CAPES 1500-2500 J/KG AND
BULK SHEAR INCREASING TO 30 TO 40 KTS. EXPECT HIGHS ON THURSDAY
TO RANGE FROM THE MID 70S NORTHWEST TO MID 80S SOUTHEAST WITH LOWS
THURSDAY NIGHT RANGING FROM THE UPPER 40S NORTHWEST TO UPPER 50S
TO AROUND 60 SOUTHEAST.
FRIDAY AND FRIDAY NIGHT...STILL CANNOT RULE OUT A FEW SHOWERS ON
FRIDAY AS UPPER TROUGH AXIS AND ASSOCIATED VORT MAX SWING ACRS FA.
ON FRIDAY NIGHT ANY LINGERING SCATTERED SHOWERS SHOULD BE
CONFINED TO EXTREME NORTHEAST PORTION OF FA AS UPPER TROUGH AXIS
GRADUALLY SLIDES EAST OF FA. EXPECT MUCH COOLER CONDITIONS WITH
HIGHS ON FRIDAY ONLY RANGING FROM THE MID 50S NORTHWEST TO UPPER
60S TO AROUND 70 SOUTHEAST. LOWS FRIDAY NIGHT ARE EXPECTED TO
RANGE FROM THE UPPER 30S NORTHWEST TO MID 40S SOUTHEAST.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AN UPPER LEVEL TROUGH WILL BE LIFTING NORTH OF NY AND NEW ENGLAND TO
OPEN THE WEEKEND. SFC HIGH PRESSURE WILL BE RIDGING IN FROM THE
LOWER GREAT LAKES AND OHIO. NW FLOW WILL DOMINATE ALOFT. COOL AND
BREEZY CONDITIONS ARE EXPECTED ON SATURDAY...AS H850 TEMPS WILL BE
ONLY +3C TO +5C OVER THE FCST AREA BY MID PM. MAX TEMPS WILL RUN
ABOUT 10 DEGREES BELOW NORMAL WITH HIGHS 60-65F IN THE VALLEYS...AND
GENERALLY MID TO U50S OVER THE HILLS AND MTNS.
SATURDAY NIGHT INTO SUNDAY...THE SFC HIGH MOVES OVER NY AND PA...AND
THEN SLIDES SOUTH AND EAST OFF THE NJ COAST. LOW AND MID LEVEL WARM
ADVECTION WILL OCCUR OVER THE REGION. AFTER A COOL START SUNDAY
MORNING WITH MIN TEMPS RUNNING FROM THE MID AND U30S OVER THE
SRN DACKS TO LOWER TO MID 40S OVER THE HUDSON RIVER VALLEY AND NW
CT...A NICE SUNDAY IS EXPECTED. PARTLY TO MOSTLY SUNNY CONDITIONS
WILL PREVAIL WITH TEMPS MAINLY IN THE 60S TO A FEW L70S OVER THE MID
HUDSON VALLEY. ANOTHER LONG-WAVE UPPER LEVEL TROUGH WILL BE MOVING
EASTWARD ACROSS HUDSON BAY. THIS UPPER TROUGH WILL ALLOW A COLD
FRONT TO APPROACH FROM THE GREAT LAKES REGION AND ST LAWRENCE RIVER
VALLEY FOR THE OPENING OF THE WORK AND SCHOOL WEEK.
SUNDAY NIGHT INTO MONDAY...THE MEDIUM RANGE GUIDANCE VARIES SLIGHTLY
ON THE TIMING AND PASSAGE OF THE COLD FRONT. THE WPC GUIDANCE WAS A
GOOD COMPROMISE WITH THE BOUNDARY MOVING THROUGH IN THE LATE MORNING
AND EARLY PM. SOME LAKE MOISTURE MAY BE UTILIZED...BUT THE OVERALL
LOW-LEVEL CONVERGENCE WITH A PRE-FRONTAL SFC TROUGH...AND THE ACTUAL
COLD FRONT LOOKS PRETTY MEAGER. SLIGHT TO LOW CHC POPS WERE USED
SUNDAY NIGHT UNTIL LUNCH-TIME ON MONDAY FROM THE I-90 CORRIDOR
NORTHWARD FOR SHOWERS. LOWS MONDAY MORNING ARE EXPECTED IN THE 40S
TO L50S...WITH HIGHS SIMILAR TO SUNDAY...BUT A SHADE COOLER OVER THE
SRN GREENS AND SRN DACKS.
MONDAY NIGHT INTO TUESDAY...ANOTHER BROAD CANADIAN SFC ANTICYCLONE
WILL BUILD IN ACROSS THE NORTHEAST FROM SE ONTARIO AND THE UPPER
GREAT LAKES REGION. THE SUBSIDENCE FROM THE HIGH WILL YIELD CLEAR
AND COOL CONDITIONS WITH TEMPS STILL RUNNING BELOW NORMAL FOR MID
SEPT.
OVERALL...PCPN AND TEMPS LOOK BELOW NORMAL IN THE LONG TERM.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
A WARM AND HUMID AIR MASS CONTINUES TO IMPACT THE REGION THIS
MORNING INTO THE AFTERNOON. A WEAK MID LEVEL DISTURBANCE IN THE
W/SW FLOW ALOFT MAY PRODUCE ISOLD-SCT SHOWERS AND THUNDERSTORMS
IN THE LATE AFTERNOON. A COLD FRONT WILL INCREASE THE COVERAGE OF
SHOWERS AND THUNDERSTORMS WED NIGHT INTO THU.
THE CLEAR SKIES AND LIGHT TO CALM WINDS HAVE LET RADIATIONAL
MIST/FOG FORM AT KGFL/KPSF/KPOU. SOME LOW STRATUS IN THE LIFR/IFR
RANGE HAS ALSO OCCURRED AT KGFL/KPSF. MVFR MIST HAS OCCURRED AT
KALB. A GRADUAL IMPROVEMENT TO VFR LEVELS WILL OCCUR AT
KPOU/KPSF/KGFL BTWN 14Z-16Z. VFR CONDITIONS WILL OCCUR INTO THE
MID PM...AND THEN THAT MID LEVEL DISTURBANCE OR SFC TROUGH COULD
FOCUS THE ISOLD-SCT SHOWERS AND THUNDERSTORMS. VCSH GROUPS HAVE
BEEN USED AT THIS TIME. CIG BASES WILL BE IN THE 4-5 KFT AGL
RANGE.
THE SKIES SHOULD CLEAR A BIT AFTER 00Z/THU...THIS MAY ALLOW
FOR SOME PATCHY MIST/FG AGAIN...ESPECIALLY AT KPSF AND KGFL.
MVFR/IFR CONDITIONS HAVE BEEN PLACED IN THE TAF SITES AT THIS TIME.
THE WINDS WILL BE LIGHT AND VARIABLE AT LESS THAN 5 KTS AT ALL THE
TAF SITES...EXCEPT AT KALB WHERE A LIGHT S WIND OF 4-7 KTS WILL
CONTINUE THIS MORNING. THE WINDS WILL INCREASE FROM THE SOUTH TO
SOUTHWEST AT 8 TO 13 KTS DURING THE PM...WITH A FEW GUSTS AROUND
20-25 KTS AT KALB/KPSF. THE WINDS WILL LIGHTEN TO LESS THAN 7 KTS
AFTER 01Z/THU.
OUTLOOK...
THURSDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
FRIDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA.
FRIDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
SATURDAY TO SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY:LOW OPERATIONAL IMPACT. ISOLATED SHRA.
&&
.FIRE WEATHER...
NO FIRE WEATHER RELATED ISSUES ARE ANTICIPATED OVER THE NEXT
SEVERAL DAYS.
HAZY...HOT AND HUMID CONDITIONS ARE IN STORE FOR OUR REGION TODAY
WITH A CHANCE FOR A SHOWER OR THUNDERSTORM. A STRONG COLD
FRONT...ACCOMPANIED BY WIDESPREAD SHOWERS AND THUNDERSTORMS WITH
HEAVY RAIN...WILL MOVE ACROSS THE REGION THURSDAY USHERING IN A
MUCH COOLER AND LESS HUMID AUTUMN AIR MASS FOR THE REMAINDER OF
THE WEEK.
&&
.HYDROLOGY...
WIDELY SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS...SOME
WITH VERY HEAVY DOWNPOURS...ARE EXPECTED ACROSS THE HSA DURING THE
AFTERNOON AND EVENING HOURS TODAY LIKELY ASSOCIATED WITH A PRE
FRONTAL TROUGH. MORE WIDESPREAD CONVECTION IS EXPECTED LATE
TONIGHT INTO THURSDAY EVENING WITH HEAVY RAINFALL AS ONE OR MORE
WAVES OF LOW PRESSURE ARE EXPECTED TO TRACK NORTHEAST ALONG A
STRONG COLD FRONT WHICH WILL BE DROPPING SOUTHEAST THROUGH OUR
REGION LATE THURSDAY AND THURSDAY NIGHT. DRIER AND COOLER WEATHER
IS EXPECTED TO END THE WEEK
WITHIN ANY SHOWER OR THUNDERSTORM...THERE WILL BE THE POTENTIAL FOR
MINOR FLOODING OF POOR DRAINAGE...URBAN...AND LOW LYING AREAS DUE TO
VERY HEAVY RAINFALL IN A SHORT PERIOD OF TIME TODAY THROUGH
THIS EVENING. LATE TONIGHT THROUGH THURSDAY EVENING EXPECT A MORE
WIDESPREAD HEAVY RAIN EVENT WITH SIGNIFICANT RISES OCCURRING ON
SOME MAIN STEM RIVERS WITH UP TO SEVERAL INCHES OF RAIN POSSIBLE.
IN ADDITION FLOODING OF SMALL STREAMS AND CREEKS MAY ALSO OCCUR.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR CTZ001-013.
NY...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR NYZ041-049-050-
052-053-059-060-064-065-083-084.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS/JPV
SHORT TERM...11
LONG TERM...WASULA
AVIATION...WASULA
FIRE WEATHER...11
HYDROLOGY...11
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
503 PM CDT WED SEP 11 2013
.DISCUSSION...
249 PM CDT
SYNOPSIS...A COUPLE OF COLD FRONTS PASS THROUGH THE REGION BRINGING
SCATTERED SHOWERS AND MUCH COOLER AIR TO THE REGION.
TODAY AND TONIGHT...
A COLD FRONT IS OVER NORTHERN IL AND STRETCHES INTO CENTRAL MI.
SHOWERS AND A FEW STORMS ARE FIRING ALONG THE FRONT...WITH THE
STRONGER STORMS ASSOCIATED WITH VARIOUS BOUNDARIES OVER NORTHERN
IL. THE TWO MAIN BOUNDARIES APPEAR TO BE THE LAKE BREEZE OVER
NORTHERN COOK COUNTY AND AN OUTFLOW BOUNDARY FROM THE NORTHERN
SHOWERS THAT STRETCHES FROM PAW PAW TO ELMHURST. EXPECTING MUCH OF
THE SAME THIS AFTERNOON WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. THE STRONGER STORMS WILL BE ASSOCIATED WITH BETTER
AREAS OF FORCING. LATEST RAP ANALYSIS INDICATE CAPE VALUES UP TO
2000 J/KG OVER THE REGION. THE BEST 0-6 KM SHEAR IS NORTH OF I-88
WHERE SHOWERS HAVE STABILIZED THE ENVIRONMENT. AREAS SOUTH OF I-88
AND THE COLD FRONT REMAIN RELATIVELY CLEAR WITH LOW LEVEL LAPSE
RATES AT OR ABOVE 9C/KM BUT UPPER LEVEL LAPSE RATES REMAIN WEAK
AROUND 6C/KM. SHEAR IS ALSO LESS THAN DESIRABLE SO EXPECTING
SHOWERS AND STORMS TO DEVELOP AS THE FRONT SINKS SOUTH...BUT NOT
ANTICIPATING ANY WELL ORGANIZED STORMS. MAIN THREAT REMAINS
ISOLATED DAMAGING WINDS OR A DOWNBURST GIVEN PWAT VALUES 1.5+ WHICH
IS +2SD ABOVE NORMAL FOR SEPTEMBER. SOUNDINGS ALSO FEATURE INVERTED
VS BELOW 700MB. WIDESPREAD SEVERE WEATHER IS NOT LIKELY GIVEN THE
MARGINAL CONDITIONS AND WEAK FORCING.
EXPECTING THE FRONT AND ASSOCIATED PRECIP TO MOVE SOUTH OF I-88 LATE
THIS AFTERNOON INTO THIS EVENING AND CONTINUE TO THE SOUTH
OVERNIGHT. EXPECTING SKIES TO THIN OVERNIGHT AND TEMPS TO DROP TO
AROUND 60 NORTH OF I-88 AND THEN INTO THE MID TO UPPER 60S ALONG AND
SOUTH OF I-80...AND DOWNTOWN.
THURSDAY THROUGH FRIDAY...
THE TROUGH AXIS OF THE UPPER LEVEL TROUGH PASSES OVER THE REGION
TOMORROW ALONG WITH A SECONDARY COLD FRONT. NOT EXPECTING ANY
PRECIP WITH THE SECONDARY FRONT...BUT TEMPS WILL FALL. GUIDANCE
SUGGESTS 850MB TEMPS WILL BE -2 TO 6 DEGREES C BY FRIDAY MORNING.
GIVEN THAT LAKE WATER TEMPS ARE AROUND 21 DEGREES C LAKE EFFECT RAIN
BECOMES A CONCERN THURSDAY NIGHT THROUGH FRIDAY. WINDS TURN OUT OF
THE NORTHEAST AHEAD OF THE BUILDING HIGH PRESSURE...WHICH CREATE AN
ELONGATED FETCH DOWN THE LAKE. AS SUCH HAVE A SLIGHT CHANCE TO
CHANCE OF LIGHT SHOWERS OVER LAKE AND COOK COUNTIES IN IL THURSDAY
NIGHT. WINDS SHIFT TO THE NORTH FRIDAY...THEREFORE SHIFTED THE
CHANCE OF SHOWERS OVER WESTERN COOK COUNTY AND NORTHERN IN FRIDAY.
THE SHOWERS SHOULD DISSIPATE FRIDAY AFTERNOON AS TEMPS WARM ALOFT
DUE TO THE BUILDING HIGH PRESSURE.
TEMPS LATE THIS WEEK WILL BE MUCH MORE FALL LIKE...AND BELOW
NORMAL. THURSDAYS HIGHS WILL BE IN THE MID 70S TO MID 80S...AND
FRIDAYS HIGHS WILL BE IN THE MID TO UPPER 60S. OVERNIGHT LOWS WILL
BE IN THE 50S THURSDAY AND 40S ON FRIDAY.
EXTENDED...SATURDAY THROUGH TUESDAY...
THE UPPER LEVEL RIDGE REMAINS OVER TEXAS WHILE THE NOW MOBILE UPPER
LEVEL LOW WEAKENS AND DISSIPATES SATURDAY NIGHT. A SHORTWAVE TROUGH
PASSES OVER SOUTHERN WI/NORTHERN IL SATURDAY NIGHT THEN THE TROUGH
AXIS OF A LOW OVER HUDSON BAY ROTATES OVER THE REGION SUNDAY.
RIDGING FOLLOWS BEHIND THE TROUGH INTO MID NEXT WEEK.
AT THE SURFACE THE EXTENDED BEGINS WITH HIGH PRESSURE DEPARTING TO
THE SOUTHEAST. A WEAK SURFACE TROUGH PASSES OVER THE REGION SUNDAY
BRINGING A CHANCE OF RAIN AND THUNDERSTORMS. HIGH PRESSURE MOVES IN
BEHIND THE TROUGH MONDAY WITH A RETURN TO DRY CONDITIONS. THE HIGH
SHIFTS EAST AND A SHORTWAVE TROUGH MAY BRING ANOTHER ROUND OF
SHOWERS AND STORMS TUESDAY NIGHT INTO WEDNESDAY. OVERALL NOT SEEING
A GOOD CHANCE FOR THE SOAKING RAIN WE NEED.
BELOW NORMAL TEMPS ARE EXPECTED OVER THE WEEKEND WITH HIGH TEMPS IN
THE LOW 70S AND OVERNIGHT LOWS IN THE 50S. A WARM UP TO MORE
SEASONAL TEMPS IS EXPECTED TUESDAY INTO WEDNESDAY.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* WIND DIRECTION THROUGH THIS EVENING. CMS
//DISCUSSION...UPDATED 22Z...
WINDS ARE RETURNING TO A WEST/NORTHWEST DIRECTION AFTER VARIOUS
BOUNDARIES/WIND SHIFTS ALONG WITH A FEW TSRA MOVED THROUGH THE
AREA. CONFIDENCE REGARDING SOME FORM OF WESTERLY WINDS IS MEDIUM
INTO THIS EVENING...BUT THE ACTUAL DIRECTIONS COULD BE QUITE
VARIABLE AT TIMES. WIND SPEEDS SHOULD REMAIN UNDER 10 KTS. ANY
ADDITIONAL SHRA/TSRA WILL REMAIN SOUTH AND EAST OF ORD/MDW. CMS
PREVIOUS 18Z DISCUSSION...
MAIN FORECAST CONCERNS THIS AFTERNOON REVOLVE AROUND THE DETAILS OF
A COLD FRONT THAT IS CURRENTLY VERY DIFFUSE AND UNORGANIZED...
STRETCHING ROUGHLY FROM NEAR MKE SOUTHWEST TO MLI. LIGHT RETURNS
ARE SHOWING UP ON RADAR INDICATING A FEW SHOWERS ALONG THE
FRONT...AND SATELLITE IMAGERY INDICATES THAT THERE IS SOME VERTICAL
GROWTH...BUT THICK MID LEVEL CLOUD CANOPY ADVECTING OVER THE AREA
WILL ONLY INHIBIT FURTHER DESTABILIZATION THIS AFTERNOON...WHICH
ALREADY WAS A CONCERN LEADING UP TO THIS POINT. IN ADDITION TO THE
MEAGER INSTABILITY...FORCING IS VERY WEAK...MAINLY ASSOCIATED WITH
THE VERY MODEST CONVERGENCE ALONG THE FRONT ITSELF. LITTLE IF ANY
UPPER LEVEL SUPPORT IS NOTED THIS AFTERNOON. SEVERAL HI-RES
MODELS SEEM TO FALL IN TWO CAMPS...SHOWING THE CURRENT ACTIVITY TO
OUR WEST INCREASING IN INTENSITY AND COVERAGE OVER THE NEXT COUPLE
HOURS...OR THE CURRENT ACTIVITY TO OUR WEST STAYING AS IS OR
FADING. GIVEN THE AFOREMENTIONED LACK OF FORCING...LEANING TOWARDS
THE FRONT MORE OR LESS REMAINING QUIET AS IT IS NOW AS IT MOVES
OVER THE TERMINALS. IF THE FRONT WERE TO LIGHT UP LATER TODAY...IT
MAY BE SOUTH OF THE TERMINALS AS THE FRONT MOVES INTO MORE
UNSTABLE AIRMASS. WITH THAT IN MIND...REMOVED THUNDER MENTION FROM
THE TERMINALS...EXCEPT FOR GYY WHICH SEEM TO HAVE THE BEST CHANCE
FOR POSSIBLY SEEING SOMETHING MID TO LATE AFTERNOON. OVERALL
CONFIDENCE IN THE EVOLUTION THE NEXT FEW HOURS IS PRETTY LOW AND
WILL HAVE TO MONITOR RADAR TRENDS CLOSELY FOR FURTHER ADJUSTMENTS.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM FOR WIND DIRECTIONS/SPEEDS INTO THIS EVENING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...LAKE EFFECT STRATOCU CLOUDS MAY REACH
FAR ENOUGH INLAND TO PRODUCE MVFR CEILINGS.
SATURDAY...VFR. WX NIL.
SUNDAY...PREVAILING VFR. CHANCE OF SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS.
MONDAY AND TUESDAY..VFR. WX NIL.
TRS
&&
.MARINE...
142 PM CDT
A STRONGER COLD FRONT IS EXPECTED TO PUSH DOWN THE LAKE TONIGHT AS
LOW PRESSURE TRACKS FROM ONTARIO INTO QUEBEC. THE WINDS BEHIND THIS
FRONT WILL BECOME NORTHERLY UP TO 25 KT INTO THURSDAY. THESE
NORTHERLY WINDS MAY INCREASE A BIT MORE CLOSER TO 30KT FOR A PERIOD
LATER THURSDAY AND INTO THURSDAY NIGHT AS A MUCH COOLER AIRMASS
DROPS ACROSS THE LAKE AHEAD OF A CANADIAN HIGH PRESSURE SYSTEM. THE
WINDS WILL LIKELY REMAIN ELEVATED OUT OF THE NORTH INTO FRIDAY
BEFORE THE SURFACE HIGH CENTERS ITSELF OVER THE LAKE BY FRIDAY
EVENING...LEADING TO A PERIOD OF LIGHT AND VARIABLE WINDS. FOLLOWING
THE PASSAGE OF THIS HIGH...THE WINDS SHOULD BECOME SOUTHERLY AGAIN
FOR SATURDAY...BEFORE YET ANOTHER COLD FRONT LIKELY DROPS SOUTH
ACROSS THE LAKE LATER IN THE WEEKEND SETTING UP ANOTHER PERIOD OF
STRONGER NORTHERLY FLOW.
THESE STRONG NORTHERLY WINDS WILL LEAD TO SOME HIGH WAVES OF 6 TO 10
FT ACROSS FAR SOUTHERN LAKE MICHIGAN THURSDAY NIGHT INTO
FRIDAY...INCLUDING THE NEAR SHORE WATERS. THEREFORE A SMALL CRAFT
ADVISORY WILL BE NEEDED FOR THE ILLINOIS AND INDIANA NEAR SHORES
FROM THURSDAY AFTERNOON THROUGH FRIDAY NIGHT.
THERE IS ALSO A SMALL THREAT FOR SOME WATER SPOUTS LATE THURSDAY AND
INTO FRIDAY. HOWEVER...IT APPEARS TO BE A SMALL WINDOW AS UPPER
LEVEL TEMPERATURES WILL BEGIN TO WARM QUICKLY EARLY
FRIDAY...LIMITING THE OVERALL DEPTH OF THE INSTABILITY. IN SPITE OF
THIS...WE WILL MAINTAIN THE CHANCES FOR SOME ISOLATED WATER SPOUTS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM THURSDAY TO 5 AM
SATURDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM THURSDAY TO 5 AM
SATURDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...1 PM THURSDAY TO 5 AM SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
301 PM CDT WED SEP 11 2013
.DISCUSSION...
249 PM CDT
SYNOPSIS...A COUPLE OF COLD FRONTS PASS THROUGH THE REGION BRINGING
SCATTERED SHOWERS AND MUCH COOLER AIR TO THE REGION.
TODAY AND TONIGHT...
A COLD FRONT IS OVER NORTHERN IL AND STRETCHES INTO CENTRAL MI.
SHOWERS AND A FEW STORMS ARE FIRING ALONG THE FRONT...WITH THE
STRONGER STORMS ASSOCIATED WITH VARIOUS BOUNDARIES OVER NORTHERN
IL. THE TWO MAIN BOUNDARIES APPEAR TO BE THE LAKE BREEZE OVER
NORTHERN COOK COUNTY AND AN OUTFLOW BOUNDARY FROM THE NORTHERN
SHOWERS THAT STRETCHES FROM PAW PAW TO ELMHURST. EXPECTING MUCH OF
THE SAME THIS AFTERNOON WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. THE STRONGER STORMS WILL BE ASSOCIATED WITH BETTER
AREAS OF FORCING. LATEST RAP ANALYSIS INDICATE CAPE VALUES UP TO
2000 J/KG OVER THE REGION. THE BEST 0-6 KM SHEAR IS NORTH OF I-88
WHERE SHOWERS HAVE STABILIZED THE ENVIRONMENT. AREAS SOUTH OF I-88
AND THE COLD FRONT REMAIN RELATIVELY CLEAR WITH LOW LEVEL LAPSE
RATES AT OR ABOVE 9C/KM BUT UPPER LEVEL LAPSE RATES REMAIN WEAK
AROUND 6C/KM. SHEAR IS ALSO LESS THAN DESIRABLE SO EXPECTING
SHOWERS AND STORMS TO DEVELOP AS THE FRONT SINKS SOUTH...BUT NOT
ANTICIPATING ANY WELL ORGANIZED STORMS. MAIN THREAT REMAINS
ISOLATED DAMAGING WINDS OR A DOWNBURST GIVEN PWAT VALUES 1.5+ WHICH
IS +2SD ABOVE NORMAL FOR SEPTEMBER. SOUNDINGS ALSO FEATURE INVERTED
VS BELOW 700MB. WIDESPREAD SEVERE WEATHER IS NOT LIKELY GIVEN THE
MARGINAL CONDITIONS AND WEAK FORCING.
EXPECTING THE FRONT AND ASSOCIATED PRECIP TO MOVE SOUTH OF I-88 LATE
THIS AFTERNOON INTO THIS EVENING AND CONTINUE TO THE SOUTH
OVERNIGHT. EXPECTING SKIES TO THIN OVERNIGHT AND TEMPS TO DROP TO
AROUND 60 NORTH OF I-88 AND THEN INTO THE MID TO UPPER 60S ALONG AND
SOUTH OF I-80...AND DOWNTOWN.
THURSDAY THROUGH FRIDAY...
THE TROUGH AXIS OF THE UPPER LEVEL TROUGH PASSES OVER THE REGION
TOMORROW ALONG WITH A SECONDARY COLD FRONT. NOT EXPECTING ANY
PRECIP WITH THE SECONDARY FRONT...BUT TEMPS WILL FALL. GUIDANCE
SUGGESTS 850MB TEMPS WILL BE -2 TO 6 DEGREES C BY FRIDAY MORNING.
GIVEN THAT LAKE WATER TEMPS ARE AROUND 21 DEGREES C LAKE EFFECT RAIN
BECOMES A CONCERN THURSDAY NIGHT THROUGH FRIDAY. WINDS TURN OUT OF
THE NORTHEAST AHEAD OF THE BUILDING HIGH PRESSURE...WHICH CREATE AN
ELONGATED FETCH DOWN THE LAKE. AS SUCH HAVE A SLIGHT CHANCE TO
CHANCE OF LIGHT SHOWERS OVER LAKE AND COOK COUNTIES IN IL THURSDAY
NIGHT. WINDS SHIFT TO THE NORTH FRIDAY...THEREFORE SHIFTED THE
CHANCE OF SHOWERS OVER WESTERN COOK COUNTY AND NORTHERN IN FRIDAY.
THE SHOWERS SHOULD DISSIPATE FRIDAY AFTERNOON AS TEMPS WARM ALOFT
DUE TO THE BUILDING HIGH PRESSURE.
TEMPS LATE THIS WEEK WILL BE MUCH MORE FALL LIKE...AND BELOW
NORMAL. THURSDAYS HIGHS WILL BE IN THE MID 70S TO MID 80S...AND
FRIDAYS HIGHS WILL BE IN THE MID TO UPPER 60S. OVERNIGHT LOWS WILL
BE IN THE 50S THURSDAY AND 40S ON FRIDAY.
EXTENDED...SATURDAY THROUGH TUESDAY...
THE UPPER LEVEL RIDGE REMAINS OVER TEXAS WHILE THE NOW MOBILE UPPER
LEVEL LOW WEAKENS AND DISSIPATES SATURDAY NIGHT. A SHORTWAVE TROUGH
PASSES OVER SOUTHERN WI/NORTHERN IL SATURDAY NIGHT THEN THE TROUGH
AXIS OF A LOW OVER HUDSON BAY ROTATES OVER THE REGION SUNDAY.
RIDGING FOLLOWS BEHIND THE TROUGH INTO MID NEXT WEEK.
AT THE SURFACE THE EXTENDED BEGINS WITH HIGH PRESSURE DEPARTING TO
THE SOUTHEAST. A WEAK SURFACE TROUGH PASSES OVER THE REGION SUNDAY
BRINGING A CHANCE OF RAIN AND THUNDERSTORMS. HIGH PRESSURE MOVES IN
BEHIND THE TROUGH MONDAY WITH A RETURN TO DRY CONDITIONS. THE HIGH
SHIFTS EAST AND A SHORTWAVE TROUGH MAY BRING ANOTHER ROUND OF
SHOWERS AND STORMS TUESDAY NIGHT INTO WEDNESDAY. OVERALL NOT SEEING
A GOOD CHANCE FOR THE SOAKING RAIN WE NEED.
BELOW NORMAL TEMPS ARE EXPECTED OVER THE WEEKEND WITH HIGH TEMPS IN
THE LOW 70S AND OVERNIGHT LOWS IN THE 50S. A WARM UP TO MORE
SEASONAL TEMPS IS EXPECTED TUESDAY INTO WEDNESDAY.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* CONVECTIVE CHANCES AS A COLD FRONT SAGS ACROSS THE REGION THIS
AFTERNOON. APPEARS BEST CHANCE FOR THUNDERSTORMS WILL BE ALONG
AND SOUTH OF A LINE FROM ARR TO MDW...BUT CANNOT COMPLETELY RULE
OUT SOMETHING FARTHER NORTH.
* WIND TRENDS THIS AFTERNOON...MULTIPLE OUTFLOW BOUNDARIES IN THE
AREA HAVE LED TO VERY MESSY WIND FIELD. WINDS SHOULD GENERALLY
BE LESS THAN 10 KT OUTSIDE THE INFLUENCE OF CONVECTIVE OUTFLOW.
BMD
//DISCUSSION...UPDATED 18Z...
MAIN FORECAST CONCERNS THIS AFTERNOON REVOLVE AROUND THE DETAILS OF
A COLD FRONT THAT IS CURRENTLY VERY DIFFUSE AND UNORGANIZED...
STRETCHING ROUGHLY FROM NEAR MKE SOUTHWEST TO MLI. LIGHT RETURNS
ARE SHOWING UP ON RADAR INDICATING A FEW SHOWERS ALONG THE
FRONT...AND SATELLITE IMAGERY INDICATES THAT THERE IS SOME VERTICAL
GROWTH...BUT THICK MID LEVEL CLOUD CANOPY ADVECTING OVER THE AREA
WILL ONLY INHIBIT FURTHER DESTABILIZATION THIS AFTERNOON...WHICH
ALREADY WAS A CONCERN LEADING UP TO THIS POINT. IN ADDITION TO THE
MEAGER INSTABILITY...FORCING IS VERY WEAK...MAINLY ASSOCIATED WITH
THE VERY MODEST CONVERGENCE ALONG THE FRONT ITSELF. LITTLE IF ANY
UPPER LEVEL SUPPORT IS NOTED THIS AFTERNOON. SEVERAL HI-RES
MODELS SEEM TO FALL IN TWO CAMPS...SHOWING THE CURRENT ACTIVITY TO
OUR WEST INCREASING IN INTENSITY AND COVERAGE OVER THE NEXT COUPLE
HOURS...OR THE CURRENT ACTIVITY TO OUR WEST STAYING AS IS OR
FADING. GIVEN THE AFOREMENTIONED LACK OF FORCING...LEANING TOWARDS
THE FRONT MORE OR LESS REMAINING QUIET AS IT IS NOW AS IT MOVES
OVER THE TERMINALS. IF THE FRONT WERE TO LIGHT UP LATER TODAY...IT
MAY BE SOUTH OF THE TERMINALS AS THE FRONT MOVES INTO MORE
UNSTABLE AIRMASS. WITH THAT IN MIND...REMOVED THUNDER MENTION FROM
THE TERMINALS...EXCEPT FOR GYY WHICH SEEM TO HAVE THE BEST CHANCE
FOR POSSIBLY SEEING SOMETHING MID TO LATE AFTERNOON. OVERALL
CONFIDENCE IN THE EVOLUTION THE NEXT FEW HOURS IS PRETTY LOW AND
WILL HAVE TO MONITOR RADAR TRENDS CLOSELY FOR FURTHER ADJUSTMENTS.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN CONVECTIVE TRENDS ALONG THE FRONT THROUGH
THIS AFTERNOON...MEDIUM CONFIDENCE THAT TSRA WILL STAY SOUTH OF
ORD.
* HIGH CONFIDENCE IN VFR CONDITIONS OUTSIDE THE INFLUENCE OF
SHRA/TSRA.
* LOW CONFIDENCE IN WIND DIRECTION THIS AFTERNOON. MEDIUM
CONFIDENCE IN WINDS STAYING LESS THAN 10 KT OUTSIDE THE
INFLUENCE OF AN OUTFLOW BOUNDARY.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...LAKE EFFECT STRATOCU CLOUDS MAY REACH
FAR ENOUGH INLAND TO PRODUCE MVFR CEILINGS.
SATURDAY...VFR. WX NIL.
SUNDAY...PREVAILING VFR. CHANCE OF SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS.
MONDAY AND TUESDAY..VFR. WX NIL.
TRS
&&
.MARINE...
142 PM CDT
A STRONGER COLD FRONT IS EXPECTED TO PUSH DOWN THE LAKE TONIGHT AS
LOW PRESSURE TRACKS FROM ONTARIO INTO QUEBEC. THE WINDS BEHIND THIS
FRONT WILL BECOME NORTHERLY UP TO 25 KT INTO THURSDAY. THESE
NORTHERLY WINDS MAY INCREASE A BIT MORE CLOSER TO 30KT FOR A PERIOD
LATER THURSDAY AND INTO THURSDAY NIGHT AS A MUCH COOLER AIRMASS
DROPS ACROSS THE LAKE AHEAD OF A CANADIAN HIGH PRESSURE SYSTEM. THE
WINDS WILL LIKELY REMAIN ELEVATED OUT OF THE NORTH INTO FRIDAY
BEFORE THE SURFACE HIGH CENTERS ITSELF OVER THE LAKE BY FRIDAY
EVENING...LEADING TO A PERIOD OF LIGHT AND VARIABLE WINDS. FOLLOWING
THE PASSAGE OF THIS HIGH...THE WINDS SHOULD BECOME SOUTHERLY AGAIN
FOR SATURDAY...BEFORE YET ANOTHER COLD FRONT LIKELY DROPS SOUTH
ACROSS THE LAKE LATER IN THE WEEKEND SETTING UP ANOTHER PERIOD OF
STRONGER NORTHERLY FLOW.
THESE STRONG NORTHERLY WINDS WILL LEAD TO SOME HIGH WAVES OF 6 TO 10
FT ACROSS FAR SOUTHERN LAKE MICHIGAN THURSDAY NIGHT INTO
FRIDAY...INCLUDING THE NEAR SHORE WATERS. THEREFORE A SMALL CRAFT
ADVISORY WILL BE NEEDED FOR THE ILLINOIS AND INDIANA NEAR SHORES
FROM THURSDAY AFTERNOON THROUGH FRIDAY NIGHT.
THERE IS ALSO A SMALL THREAT FOR SOME WATER SPOUTS LATE THURSDAY AND
INTO FRIDAY. HOWEVER...IT APPEARS TO BE A SMALL WINDOW AS UPPER
LEVEL TEMPERATURES WILL BEGIN TO WARM QUICKLY EARLY
FRIDAY...LIMITING THE OVERALL DEPTH OF THE INSTABILITY. IN SPITE OF
THIS...WE WILL MAINTAIN THE CHANCES FOR SOME ISOLATED WATER SPOUTS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM THURSDAY TO 5 AM
SATURDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM THURSDAY TO 5 AM
SATURDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...1 PM THURSDAY TO 5 AM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
253 PM CDT WED SEP 11 2013
.DISCUSSION...
249 PM CDT
SYNOPSIS...A COUPLE OF COLD FRONTS PASS THROUGH THE REGION BRINGING
SCATTERED SHOWERS AND MUCH COOLER AIR TO THE REGION.
TODAY AND TONIGHT...
A COLD FRONT IS OVER NORTHERN IL AND STRETCHES INTO CENTRAL MI.
SHOWERS AND A FEW STORMS ARE FIRING ALONG THE FRONT...WITH THE
STRONGER STORMS ASSOCIATED WITH VARIOUS BOUNDARIES OVER NORTHERN
IL. THE TWO MAIN BOUNDARIES APPEAR TO BE THE LAKE BREEZE OVER
NORTHERN COOK COUNTY AND AN OUTFLOW BOUNDARY FROM THE NORTHERN
SHOWERS THAT STRETCHES FROM PAW PAW TO ELMHURST. EXPECTING MUCH OF
THE SAME THIS AFTERNOON WITH SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. THE STRONGER STORMS WILL BE ASSOCIATED WITH BETTER
AREAS OF FORCING. LATEST RAP ANALYSIS INDICATE CAPE VALUES UP TO
2000 J/KG OVER THE REGION. THE BEST 0-6 KM SHEAR IS NORTH OF I-88
WHERE SHOWERS HAVE STABILIZED THE ENVIRONMENT. AREAS SOUTH OF I-88
AND THE COLD FRONT REMAIN RELATIVELY CLEAR WITH LOW LEVEL LAPSE
RATES AT OR ABOVE 9C/KM BUT UPPER LEVEL LAPSE RATES REMAIN WEAK
AROUND 6C/KM. SHEAR IS ALSO LESS THAN DESIRABLE SO EXPECTING
SHOWERS AND STORMS TO DEVELOP AS THE FRONT SINKS SOUTH...BUT NOT
ANTICIPATING ANY WELL ORGANIZED STORMS. MAIN THREAT REMAINS
ISOLATED DAMAGING WINDS OR A DOWNBURST GIVEN PWAT VALUES 1.5+ WHICH
IS +2SD ABOVE NORMAL FOR SEPTEMBER. SOUNDINGS ALSO FEATURE INVERTED
VS BELOW 700MB. WIDESPREAD SEVERE WEATHER IS NOT LIKELY GIVEN THE
MARGINAL CONDITIONS AND WEAK FORCING.
EXPECTING THE FRONT AND ASSOCIATED PRECIP TO MOVE SOUTH OF I-88 LATE
THIS AFTERNOON INTO THIS EVENING AND CONTINUE TO THE SOUTH
OVERNIGHT. EXPECTING SKIES TO THIN OVERNIGHT AND TEMPS TO DROP TO
AROUND 60 NORTH OF I-88 AND THEN INTO THE MID TO UPPER 60S ALONG AND
SOUTH OF I-80...AND DOWNTOWN.
THURSDAY THROUGH FRIDAY...
THE TROUGH AXIS OF THE UPPER LEVEL TROUGH PASSES OVER THE REGION
TOMORROW ALONG WITH A SECONDARY COLD FRONT. NOT EXPECTING ANY
PRECIP WITH THE SECONDARY FRONT...BUT TEMPS WILL FALL. GUIDANCE
SUGGESTS 850MB TEMPS WILL BE -2 TO 6 DEGREES C BY FRIDAY MORNING.
GIVEN THAT LAKE WATER TEMPS ARE AROUND 21 DEGREES C LAKE EFFECT RAIN
BECOMES A CONCERN THURSDAY NIGHT THROUGH FRIDAY. WINDS TURN OUT OF
THE NORTHEAST AHEAD OF THE BUILDING HIGH PRESSURE...WHICH CREATE AN
ELONGATED FETCH DOWN THE LAKE. AS SUCH HAVE A SLIGHT CHANCE TO
CHANCE OF LIGHT SHOWERS OVER LAKE AND COOK COUNTIES IN IL THURSDAY
NIGHT. WINDS SHIFT TO THE NORTH FRIDAY...THEREFORE SHIFTED THE
CHANCE OF SHOWERS OVER WESTERN COOK COUNTY AND NORTHERN IN FRIDAY.
THE SHOWERS SHOULD DISSIPATE FRIDAY AFTERNOON AS TEMPS WARM ALOFT
DUE TO THE BUILDING HIGH PRESSURE.
TEMPS LATE THIS WEEK WILL BE MUCH MORE FALL LIKE...AND BELOW
NORMAL. THURSDAYS HIGHS WILL BE IN THE MID 70S TO MID 80S...AND
FRIDAYS HIGHS WILL BE IN THE MID TO UPPER 60S. OVERNIGHT LOWS WILL
BE IN THE 50S THURSDAY AND 40S ON FRIDAY.
EXTENDED...SATURDAY THROUGH TUESDAY...
THE UPPER LEVEL RIDGE REMAINS OVER TEXAS WHILE THE NOW MOBILE UPPER
LEVEL LOW WEAKENS AND DISSIPATES SATURDAY NIGHT. A SHORTWAVE TROUGH
PASSES OVER SOUTHERN WI/NORTHERN IL SATURDAY NIGHT THEN THE TROUGH
AXIS OF A LOW OVER HUDSON BAY ROTATES OVER THE REGION SUNDAY.
RIDGING FOLLOWS BEHIND THE TROUGH INTO MID NEXT WEEK.
AT THE SURFACE THE EXTENDED BEGINS WITH HIGH PRESSURE DEPARTING TO
THE SOUTHEAST. A WEAK SURFACE TROUGH PASSES OVER THE REGION SUNDAY
BRINGING A CHANCE OF RAIN AND THUNDERSTORMS. HIGH PRESSURE MOVES IN
BEHIND THE TROUGH MONDAY WITH A RETURN TO DRY CONDITIONS. THE HIGH
SHIFTS EAST AND A SHORTWAVE TROUGH MAY BRING ANOTHER ROUND OF
SHOWERS AND STORMS TUESDAY NIGHT INTO WEDNESDAY. OVERALL NOT SEEING
A GOOD CHANCE FOR THE SOAKING RAIN WE NEED.
BELOW NORMAL TEMPS ARE EXPECTED OVER THE WEEKEND WITH HIGH TEMPS IN
THE LOW 70S AND OVERNIGHT LOWS IN THE 50S. A WARM UP TO MORE
SEASONAL TEMPS IS EXPECTED TUESDAY INTO WEDNESDAY.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* CONVECTIVE CHANCES AS A COLD FRONT SAGS ACROSS THE REGION THIS
AFTERNOON.
BMD
//DISCUSSION...UPDATED 18Z...
MAIN FORECAST CONCERNS THIS AFTERNOON REVOLVE AROUND THE DETAILS OF
A COLD FRONT THAT IS CURRENTLY VERY DIFFUSE AND UNORGANIZED...
STRETCHING ROUGHLY FROM NEAR MKE SOUTHWEST TO MLI. LIGHT RETURNS
ARE SHOWING UP ON RADAR INDICATING A FEW SHOWERS ALONG THE
FRONT...AND SATELLITE IMAGERY INDICATES THAT THERE IS SOME VERTICAL
GROWTH...BUT THICK MID LEVEL CLOUD CANOPY ADVECTING OVER THE AREA
WILL ONLY INHIBIT FURTHER DESTABILIZATION THIS AFTERNOON...WHICH
ALREADY WAS A CONCERN LEADING UP TO THIS POINT. IN ADDITION TO THE
MEAGER INSTABILITY...FORCING IS VERY WEAK...MAINLY ASSOCIATED WITH
THE VERY MODEST CONVERGENCE ALONG THE FRONT ITSELF. LITTLE IF ANY
UPPER LEVEL SUPPORT IS NOTED THIS AFTERNOON. SEVERAL HI-RES
MODELS SEEM TO FALL IN TWO CAMPS...SHOWING THE CURRENT ACTIVITY TO
OUR WEST INCREASING IN INTENSITY AND COVERAGE OVER THE NEXT COUPLE
HOURS...OR THE CURRENT ACTIVITY TO OUR WEST STAYING AS IS OR
FADING. GIVEN THE AFOREMENTIONED LACK OF FORCING...LEANING TOWARDS
THE FRONT MORE OR LESS REMAINING QUIET AS IT IS NOW AS IT MOVES
OVER THE TERMINALS. IF THE FRONT WERE TO LIGHT UP LATER TODAY...IT
MAY BE SOUTH OF THE TERMINALS AS THE FRONT MOVES INTO MORE
UNSTABLE AIRMASS. WITH THAT IN MIND...REMOVED THUNDER MENTION FROM
THE TERMINALS...EXCEPT FOR GYY WHICH SEEM TO HAVE THE BEST CHANCE
FOR POSSIBLY SEEING SOMETHING MID TO LATE AFTERNOON. OVERALL
CONFIDENCE IN THE EVOLUTION THE NEXT FEW HOURS IS PRETTY LOW AND
WILL HAVE TO MONITOR RADAR TRENDS CLOSELY FOR FURTHER ADJUSTMENTS.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* LOW CONFIDENCE IN CONVECTIVE TRENDS ALONG THE FRONT THROUGH THIS
AFTERNOON.
* HIGH CONFIDENCE IN VFR CONDITIONS OUTSIDE THE INFLUENCE OF
SHRA/TSRA.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT AND FRIDAY...LAKE EFFECT STRATOCU CLOUDS MAY REACH
FAR ENOUGH INLAND TO PRODUCE MVFR CEILINGS.
SATURDAY...VFR. WX NIL.
SUNDAY...PREVAILING VFR. CHANCE OF SHOWERS AND A SLIGHT CHANCE OF
THUNDERSTORMS.
MONDAY AND TUESDAY..VFR. WX NIL.
TRS
&&
.MARINE...
142 PM CDT
A STRONGER COLD FRONT IS EXPECTED TO PUSH DOWN THE LAKE TONIGHT AS
LOW PRESSURE TRACKS FROM ONTARIO INTO QUEBEC. THE WINDS BEHIND THIS
FRONT WILL BECOME NORTHERLY UP TO 25 KT INTO THURSDAY. THESE
NORTHERLY WINDS MAY INCREASE A BIT MORE CLOSER TO 30KT FOR A PERIOD
LATER THURSDAY AND INTO THURSDAY NIGHT AS A MUCH COOLER AIRMASS
DROPS ACROSS THE LAKE AHEAD OF A CANADIAN HIGH PRESSURE SYSTEM. THE
WINDS WILL LIKELY REMAIN ELEVATED OUT OF THE NORTH INTO FRIDAY
BEFORE THE SURFACE HIGH CENTERS ITSELF OVER THE LAKE BY FRIDAY
EVENING...LEADING TO A PERIOD OF LIGHT AND VARIABLE WINDS. FOLLOWING
THE PASSAGE OF THIS HIGH...THE WINDS SHOULD BECOME SOUTHERLY AGAIN
FOR SATURDAY...BEFORE YET ANOTHER COLD FRONT LIKELY DROPS SOUTH
ACROSS THE LAKE LATER IN THE WEEKEND SETTING UP ANOTHER PERIOD OF
STRONGER NORTHERLY FLOW.
THESE STRONG NORTHERLY WINDS WILL LEAD TO SOME HIGH WAVES OF 6 TO 10
FT ACROSS FAR SOUTHERN LAKE MICHIGAN THURSDAY NIGHT INTO
FRIDAY...INCLUDING THE NEAR SHORE WATERS. THEREFORE A SMALL CRAFT
ADVISORY WILL BE NEEDED FOR THE ILLINOIS AND INDIANA NEAR SHORES
FROM THURSDAY AFTERNOON THROUGH FRIDAY NIGHT.
THERE IS ALSO A SMALL THREAT FOR SOME WATER SPOUTS LATE THURSDAY AND
INTO FRIDAY. HOWEVER...IT APPEARS TO BE A SMALL WINDOW AS UPPER
LEVEL TEMPERATURES WILL BEGIN TO WARM QUICKLY EARLY
FRIDAY...LIMITING THE OVERALL DEPTH OF THE INSTABILITY. IN SPITE OF
THIS...WE WILL MAINTAIN THE CHANCES FOR SOME ISOLATED WATER SPOUTS.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...BEACH HAZARDS STATEMENT...ILZ006-ILZ014...1 PM THURSDAY TO 5 AM
SATURDAY.
IN...BEACH HAZARDS STATEMENT...INZ001-INZ002...1 PM THURSDAY TO 5 AM
SATURDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-
LMZ745...1 PM THURSDAY TO 5 AM SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
337 PM EDT WED SEP 11 2013
.SYNOPSIS...
ISSUED AT 1150 AM EDT TUE SEP 10 2013
A COLD FRONT WILL SAG SLOWLY SOUTHWARD THROUGH THE SOUTHERN GREAT
LAKES LATER TODAY. SOUTH OF THE FRONT TEMPERATURES WILL CLIMB INTO
THE LOWER TO POSSIBLY MIDDLE 90S...WITH 70S AND 80S BEHIND THE
FRONT. SOME SHOWERS AND THUNDERSTORMS MAY DEVELOP THIS AFTERNOON
AND EVENING...WITH A CHANCE OF SHOWERS AND THUNDERSTORMS
CONTINUING INTO TONIGHT. BEHIND THE FRONT...SIGNIFICANTLY COOLER
AIR WILL SPREAD THROUGH THE REGION. HIGHS ON THURSDAY WILL BE ON
THE ORDER OF 15 TO 20 DEGREES COOLER THAN TODAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 332 PM EDT WED SEP 11 2013
FOCUS OF FORECAST ON NEXT 6 TO 9 HOURS WITH CONVECTION CHANCES
ALONG/AHEAD OF COLD FRONT.
TEMPS HAVE MANAGED TO CLIMB TO AOA 90 MOST EVERYWHERE EXCEPT NEAR
THE IMMEDIATE LAKE SHORE AND FAR NE AREAS (WHICH COULD STILL MAKE IT
AT 20Z). ONSHORE WIND HAS NOW SETTLED INTO KBEH WITH A 10 DEGREE
DROP IN TEMPS AFTER A PEAK OF 89 A FEW HOURS AGO. AS MANY OF THE
HIGH RES MODELS INDICATED...LL MSTR HAS BEEN MIXED OUT WITH MOST
LOCATIONS IN THE 60 TO 63 DEGREE RANGE FOR DEWPTS. THE EXCEPTION WAS
ALONG A OUTFLOW BOUNDARY THAT HAS NOW STALLED OUT FROM WOLCOTT IN TO
COLUMBIA CITY TO MONROE MI. AN ISOLATED SHOWER OR 2 MANAGED TO POP
ACROSS MAINLY NW OHIO...BUT DIED JUST AS QUICK. 18Z DTX SOUNDING
SHOWED ANY CAPPING HAS BEEN ERODED. HOWEVER...LACK OF FORCING NW OF
THIS BOUNDARY LOOKS TO PRECLUDE ANY DEVELOPMENT UNTIL ARRIVAL OF
COLD FRONT. COLD FRONT WAS LOCATED ROUGHLY FROM QUAD CITIES IOWA TO
THE THUMB OF MICHIGAN. CLUSTER OF SHOWERS AND ISOL THUNDER WAS
MOVING ACROSS THE LAKE AND SHOWING SIGNS OF TRYING TO EXPAND
SWARD. WILL HAVE A SLGT CHC POPS IN FAR NW AREAS AND BLEND INTO
LATER THIS AFTERNOON/EVE TO REFLECT POTENTIAL FOR AT LEAST WIDELY
SCT CONVECTION AS COLD FRONT EDGES SOUTH. SVR RISK LOOKING
MINIMAL WITH MAIN FOCUS WELL SE OF THE AREA (16Z DAY 1 OUTLOOK
REMOVED MOST OF THE AREA FROM SLGT RISK) BUT STILL WORTHY OF
WATCHING OVER THE NEXT COUPLE OF HOURS. HRRR HAS SUGGESTED OVER
THE PAST FEW RUNS OF CONVECTION DEVELOPING BACK ACROSS
ILLINOIS/IOWA COULD MOVE IN LATER THIS EVENING/OVERNIGHT. POPS
LATER TONIGHT MAY NEED TO BE EXPANDED SOMEWHAT NW WARD...BUT AGAIN
CONFIDENCE IN ANY ONE SOLUTION TO LOW.
AS NOTED IN PAST DISCUSSION...AIR BEHIND THIS FRONT WILL BE COOLER
THAN PAST SEVERAL DAYS BUT PRETTY SEASONABLE FOR MID SEPT WITH HIGHS
IN THE MID TO UPR 70S. STRONGER TROUGH AND PUSH OF MUCH COLDER AIR
WILL ARRIVE THURSDAY AFTERNOON. THIS FRONT IS DYNAMICALLY MORE
IMPRESSIVE BUT SERIOUSLY LACKING MSTR (MORE SO THAN TODAY). A FEW OF
THE MODELS SHOW A FEW SHOWERS COULD IMPACT FAR NE AREAS LATE THURS
AM INTO THE AFTERNOON UNTIL FROPA BUT WILL LEAVE FORECAST DRY FOR
NOW.
&&
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 332 PM EDT WED SEP 11 2013
SIG SW TROUGH OVR SRN SK WILL CONT TO AMPLIFY SEWD THROUGH THE ST
LAW VALLEY SHRT TERM W/RAPIDLY FOLLOWING SECONDARY DISTURBANCE QUICK
ON ITS HEELS LT THU ALL CARVING OUT A RESPECTABLY DEEP TROUGH OVR
NEW ENGLAND THIS WEEKEND. STG SFC ANTICYCLONE BLDG SWD INTO THE OH
VALLEY AS THIS EVOLVES WILL BRING ABT THE COLDEST AIR OF THE SEASON
SO FAR AND IN STARK CONTRAST TO HEAT OF LAST TWO DAYS. PER MOS
TRENDS AND IN LIGHT OF TEMPS ACRS CNTRL CANADA SEE SOME VALIDITY TO
MET MOS IMPLIED MID-UPR 30 MINS SAT AM UNDERNEATH CRUX OF SFC RIDGE.
REGARDLESS BREVITY OF DEEP CAA SURGE SHRT LIVED W/PROGRESSIVE FLW
ALOFT CONTG...ALTHOUGH SEASONABLY COOL TEMPS SHLD EXTEND THROUGH SAT
BFR TEMPERED MODERATION ENSUES TIED TO THE BEGINNINGS OF LARGER
SCALE PATTN SHIFT ACRS NOAM NOTED IN MOST MED RANGE GUIDANCE AT LONG
RANGE...DYS 6-10 AND OF WHICH LOOKS TO RESULT IN A MUCH WETTER/WARMER 8-14
DY PD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 140 PM EDT WED SEP 11 2013
CONFIDENCE IN CONVECTION THROUGH THE FIRST HALF OF THE PERIOD WANING
AS OUTFLOW BOUNDARY CONTINUED TO WORK ACROSS THE AREA. AT 1730Z THIS
FEATURE WAS LOCATED FROM PONTIAC MI SE TO BETWEEN WARSAW AND
COLUMBIA CITY TO MONTICELLO. WHILE ACCAS FIELD HAS BEEN TRYING TO
ESTABLISH ITSELF ALONG THIS FEATURE...STRONG MIXING HAS DECIMATED
EARLIER CLOUD COVER WITH NEW DEVELOPMENT NOW BEING NOTED ALONG AND
EST OF THE BOUNDARY AS CONVECTIVE TEMPS APPEARS NEARLY MET. BEHIND
THIS FEATURE CHANCES FOR CONVECTION WILL LIKELY HINGE ON COLD
FRONT DROPPING IN THIS EVENING. A STRAY SHOWER/STORMS CAN`T BE
RULED OUT THIS AFTERNOON AT KFWA AS THE OUTFLOW BOUNDARY PASSES
THROUGH AND INTERACTS WITH CURRENT CU FIELD. HOWEVER...GIVEN
INHERITED TIMING OF TEMPO GROUP AND LOW CONFIDENCE...REMOVED
MENTION OF ANY CONVECTION FROM BOTH SITES. TRENDS WILL BE
MONITORED FOR INCLUSION OF CONVECTION ONCE AGAIN IN LATER
AMENDMENTS/00Z TAFS.
HAVE ALSO PUSHED BACK MAIN WIND SHIFT WITH COLD FRONT WITH SOMEWHAT
SLOWER ARRIVAL INITIALLY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...BEACH HAZARDS STATEMENT FROM THURSDAY AFTERNOON THROUGH LATE
FRIDAY NIGHT FOR INZ003.
MI...BEACH HAZARDS STATEMENT FROM THURSDAY AFTERNOON THROUGH LATE
FRIDAY NIGHT FOR MIZ077.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 2 PM THURSDAY TO 6 AM EDT SATURDAY FOR
LMZ043-046.
&&
$$
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...T
AVIATION...FISHER
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AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
104 PM EDT Wed Sep 11 2013
...Updated Aviation Discussion...
...Forecast Update...
Issued at 100 PM EDT Wed Sep 11 2013
Deformation axis continues to be oriented in a SW-NE
fashion...generally from just NW of Bowling Green to the NW of
Lexington. PW analysis from the mesoscale analysis suggest highest
slug of moisture is just to the south and east of this axis.
Showers and thunderstorms have been trying to develop along this
boundary, but they have struggled a bit with their vertical
structure. The storms have pulsed up and then quickly diminished
but have put out some good rains in their duration. Weak steering
flow has led to more of a chaotic motion with convection generally
drifting along cool outflow boundaries. As the afternoon wears on,
increased solar insolation should result in more instability being
generated with convection resulting due to differential heating and
mesoscale outflows intersecting each other. Best coverage looks to
be across KY in areas south of the Ohio River through the
afternoon. So plan on keeping the 40 PoP going with slightly lesser
PoPs across southern Indiana. May bump up coverage a bit down
across southern KY...mainly SE of a line from BWG to LEX.
Widespread Cu field and mid-level clouds have kept temperatures down
a bit. Afternoon highs in the mid-upper 80s still look likely.
Best shot at 90s actually looks to be across the north and northwest
sections where full insolation is taking place. However,
yesterday`s rainfall and resultant wet ground may keep readings a
couple of degrees cooler.
Update issued at 1019 AM EDT Wed Sep 11 2013
Morning water vapor imagery shows what appears to be a deformation
axis across central KY this morning. This deformation is
superimposed on top of a surface moisture convergence axis that
stretches from SW TN through NE KY. Combination of mid-level
cloudiness and developing Cu have kept temperatures down a little
bit over the central and western sections of the forecast
area...while clear slot over our eastern sections is allowing
destabilization to take place. Temperatures were generally in the
middle to upper 70s.
Convection has already started to pop in the areas where a weaker
cap is in place. Convection was noted up around the Dayton OH area
with a secondary batch developing just northwest of Nashville TN.
Expect the area between these two points to gradually fill in with
convection this afternoon. Unlike yesterday, the highest coverage
of PoPs will likely be along and east of I-65 this afternoon and
evening. Convection is not forecast to be severe in nature.
However, high atmospheric moisture content will result in
low-centroid efficient rainers with gusty winds and quite a bit of
CG lightning.
Current forecast has these ideas well covered and only a minor
grid/forecast update was performed...mainly to lower temperatures
slightly in the hourly T/Td to better match current observations.
Highs today look to be a few degrees cooler than Tuesday with
readings generally in the upper 80s...though a few spots may hit the
lower 90s.
.SHORT TERM (Now through Thursday)...
Issued at 310 AM EDT Wed Sep 11 2013
This morning area obs show light patchy fog. Expect this light fog
to continue to develop and persist through the pre-dawn hours
especially in fog prone areas and locations where it rained
yesterday. Don`t expect to see any dense fog as winds aloft are
mixy.
For the rest of the day, expect convection to develop this morning
over southwest Indiana/southern IL/western KY and spread eastward
through the morning hours to at least Louisville/Bowling Green and
then closer to Lexington by early afternoon. Did go ahead and bump
up timing on POPs based on 0Z NAM and latest RAP guidance. These
models did a good job with yesterday`s convection, and both seem to
agree with an area of moisture convergence and isentropic lift
developing early this morning to kick off storms. This matches SPC
deep moisture convergence mesoanalysis well. Once convection gets
going, the environment looks favorable for strong storms similar to
yesterday. The strongest storms may contain wind gusts up to 40
mph, torrential rainfall, and frequent lightning. Slow storm
motions today combined with heavy rainfall may cause minor flooding
issues especially in areas that received a lot of rainfall
yesterday. With anticipated convection a little earlier than
previously thought, did go on the cooler side of temps for highs
today especially over central KY which will probably be cloudy or
rainy much of the late morning and afternoon hours. Southern
Indiana may clear out early enough to cause temps to rebound near
peak heating. Therefore will go with a gradient of lower 90s across
southern Indiana to mid 80s over portions of central KY.
Expect a dry period tonight as today`s convection will decline with
the loss of diurnal heating/instability. Low temps will remain mild
in the upper 60s and lower 70s.
For Thurs, a cold front will cross the area bringing sct-numerous
storms. With good instability and better wind shear along the base
of an upper level trough, we`ll likely see better storm
organization. With 0-6 km bulk shear values ranging from 25-35 kts,
multicells and perhaps some bowing segments may be possible. Steep
lapse rates and dry lower levels are supportive of a damaging wind
threat. As previously mentioned, though, the bulk of the better
wind shear values looks to lag behind the main line of convection
limiting the possibility for widespread damaging winds. Still will
need to keep an eye on the potential for severe storms Thurs. With
PWATs remaining high, storms will likely contain torrential rainfall
although they should have more movement to them than storms today.
Frequent lightning will also be likely. With the front gradually
making its way south through the area on Thurs providing for plenty
of clouds and on and off convection, temps should be limited to the
mid 80s for highs.
.LONG TERM (Thursday night through Tuesday)...
Issued at 313 AM EDT Wed Sep 11 2013
Thursday night - Sunday night:
A big cooldown is coming this weekend after the passage of a cold
front Thursday/Thursday night. Have left some lingering chances for
precip in the forecast for the beginning half of Thursday night
primarily for southern KY as the front makes its way south and out
of the forecast area. By sunrise Friday morning, the rain will have
completely exited, leaving skies to clear and much cooler temps
behind. Afternoon highs are currently forecast to range from the low
to mid 70s, continuing on the same track of utilizing raw model
guidance as did the previous forecaster. Regardless of exactly how
cool highs will be for both Friday and Saturday, NCEP 850mb
temperature ensemble guidance clearly depicts the probability of
below normal anomalies at or greater than 1 standard deviation. As
surface high pressure of Canadian origin settles in over the Ohio
Valley by Saturday, have gone just a couple of degrees cooler on
Saturday versus Friday, which means that portions of the Bluegrass
region could potentially struggle to reach the 70 degree mark. Am a
little concerned that this could be a bit too low but given the
lowering sun angles for this time of year and the fact that we are
inching closer to autumn, am sticking with the raw model guidance
currently provided. This means that under plenty of nighttime
radiational cooling, lows will flirt with the 50 degree mark for
Friday and Saturday night with some notoriously cooler spots
potentially dipping down into the upper 40s. Will certainly need to
continue to monitor model trends and the incoming CAA to nail down
specific highs and lows. By Sunday, the strong surface high will
begin to weaken its grip over the Ohio Valley and traverse eastward,
off of the eastern seaboard. This allows for southerly flow to
recommence and will begin to be felt as highs on Sunday reach the
upper 70s. Sunday night lows will respond, only dropping into the
upper 50s to lower 60s.
Monday - Tuesday night:
Models diverge from each other for this time period as the ECMWF
shows a stronger upper ridge over the Deep South extending into our
neck of the woods whereas the GFS generally keeps us under zonal
flow at the 500mb level with slight perturbations rippling through
early next week. At the surface, it appears as though the region
could see the next fropa coming through on Monday but then
potentially stalling out in the vicinity of the KY-TN border.
Significant differences temporally and spatially yield a low
confidence forecast at this juncture. A few members of the GEFS hint
at precip on Monday and given that we`ll see an uptick in
lower-level moisture under southerly flow, cannot entirely rule out
the possibility of at least diurnally-driven convection on Monday
afternoon and have therefore introduced slight chance PoPs as such.
Have kept Tuesday/Tuesday night dry area-wide for now as the front
potentially remains to the south of the forecast area. Temps look to
rebound to near normal for this time frame.
&&
.AVIATION (18Z TAF Update)...
Issued at 103 PM EDT Wed Sep 11 2013
Main aviation concern will be afternoon convective coverage.
Mid-level deformation axis coincident with surface moisture
convergence axis from near KBWG to KLEX will serve as a focus for
scattered convection this afternoon. At this time, it appears that
KBWG and KLEX will likely have thunder in the vicinity this
afternoon while KSDF may have a lesser amount of coverage.
Convection is expected to diminish after sunset this evening with
skies going clear to partly cloudy. Patchy fog will also be
possible at KBWG and KLEX if the terminals get appreciable rainfall
this afternoon.
Surface winds will remain out of the southwest at 6-8kts this
afternoon and then become light and variable overnight.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
Update.........MJ
Short Term.....AMS
Long Term......lg
Aviation.......MJ
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
336 PM CDT Wed Sep 11 2013
.SHORT TERM: (Tonight through Saturday)
Issued at 334 PM CDT Wed Sep 11 2013
Primary concern for tonight will be convection developing
along/ahead of the cold front now moving southeast through Iowa.
Already seeing scattered storms over north central Missouri. SPC
meso-analysis is showing about 1000 j/kg surface CAPE up there well
ahead of the front, with as much as 2500 j/kg along the front in
Iowa. Another axis of higher cape can be found south of the STL
metro area across the eastern Ozarks. Isolated storms have
developed in this region as well. Expect the storms over the Ozarks
to diminish fairly quickly during the early evening with the loss of
daytime heating, however isolated to scattered storms should
continue across northern Missouri into west central Illinois through
much of the night as the front drifts into the area. HRRR and 4km
NCEP WRF models depict this well, and the operational NAM, GFS, and
RUC models also print out light qpf along the front as it tracks
southeast. BUFKIT soundings never really indicate much CAPE in our
area tonight, with the highest readings from the NAM at around 1000
j/kg, so would not really expect any storms that affect the area to
get too strong.
Models have the initial wind shift (perhaps driven by outflow) down
to near the I-70 corridor by 12z Thursday. The truly cooler air
lags behind up across the MO/IA border. However, the shortwave
currently over Manitoba dives down overnight and into the
Mid-Mississippi Valley by around 18z Thursday. This will sharpen up
the longwave pattern and drive the cold front south through the CWFA
by Thursday evening. Scattered showers and thunderstorms will
continue to be possible until the front comes through and
cooler/drier air settles across the region.
Temperatures will be a little cooler on Thursday, but still thinking
mid to upper 80s ahead of the front. A true taste of Fall is
expected to close out the week and start the weekend as a Canadian
high pressure system settles into the Ohio Valley. Daytime highs
will be in the low to mid 70s and overnight lows will dip into the
low to mid 50s Friday morning, and mid 40s to low 50s Saturday
morning.
Carney
.LONG TERM: (Sunday through Next Wednesday)
Issued at 334 PM CDT Wed Sep 11 2013
Sunday through Wednesday
The Canadian high will continue to move east across the Mid-Atlantic
states Sunday. Return flow will ramp up bringing warmer and more
humid air back to the region. Medium range models develop a decent
low level baroclinic zone across northern Missouri into central
Illinois. Normally, I`d be more bullish with pops in vicinity of a
baroclinic zone with southwest flow impinging on it; however with
severe drought conditions once again being reported across much of
northern Missouri, am playing it conservatively for now with only
chance and slight chance pops through mid week. Temperatures will
be near or a few degrees above normal.
Carney
&&
.AVIATION: (For the 18z TAFs through 18z Thursday Afternoon)
Issued at 1201 PM CDT Wed Sep 11 2013
Latest surface analysis shows a slow moving cold front stretching
from western Lake Superior through western Wisconsin and northern
Iowa into southeast Nebraska. Scattered showers and isolated
thunderstorms continue ahead of the front across extreme northwest
Missouri, southern Iowa, and northern Illinois.
Front will slowly make its way south across the forecast area over
the next 24 hours, bringing a wind shift to the northwest and a
chance of showers and thunderstorms. The best chance of
measurable rainfall remains across northeast Missouri and west
central Illinois tonight. Otherwise, model guidance portrays a
lull in activity as the front progresses through the center of the
forecast area (I-70 corridor) late tonight and Thursday morning
before refiring further south Thursday afternoon.
Specifics for KSTL:
VFR conditions expected with the cold front moving across the
terminal complex around 09Z. Wind will shift to the northwest.
CVKING
&&
.CLIMATE:
Issued at 342 AM CDT Wed Sep 11 2013
RECORD HIGHS:
SEPT 11
STL 97/1938
COU 100/1936
UIN 99/1936
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
435 PM CDT WED SEP 11 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 435 PM CDT WED SEP 11 2013
PRIMARY CONCERNS DURING THE NEXT 24 HOURS INCLUDE THE
COVERAGE/INTENSITY OF THUNDERSTORMS MAINLY THROUGH TONIGHT...WITH
STORM CHANCES EXPECTED TO BE ON THE WANE ACROSS ALL BUT MAINLY THE
SOUTHWEST 1/4 OF THE CWA DURING THE DAY THURSDAY. ALTHOUGH A
ROGUE...MARGINALLY SEVERE STORM CANNOT BE RULED OUT SOUTH OF
HIGHWAY 6 INTO NORTH CENTRAL KANSAS INTO THIS EVENING...THE VAST
MAJORITY OF STORMS SHOULD REMAIN SUB-SEVERE...WITH MAIN THREATS OF
50-ISH MPH WINDS AND SMALL HAIL POSSIBLY UP TO 50 MPH.
TEMP-WISE...NUDGED UP HIGHS A FEW DEGREES FOR TOMORROW IN MOST
AREAS WITH EXPECTATION OF OVERALL MORE SUN ESPECIALLY
CENTRAL/NORTHEAST AREAS AND A DRIER AIRMASS.
20Z OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A FAIRLY WELL-DEFINED WEAK
COLD FRONT/QUASI-STATIONARY FRONT DRAPED JUST SOUTH OF THE NEB/KS
LINE...EFFECTIVELY SEPARATING A LIGHT SOUTH-SOUTHEAST BREEZE FROM
A PREVAILING EAST-NORTHEAST BREEZE AROUND 10 MPH ACROSS MOST NEB
ZONES. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA
HIGHLIGHTS WEST-SOUTHWEST FLOW AT 500/700 MILLIBARS OVER THE LOCAL
AREA...AS THE CENTRAL PLAINS LIES IN BETWEEN A RIDGE AXIS CENTERED
OVER AR...A CLOSED LOW CENTERED OVER THE NV/UT/AZ BORDER
AREA...AND A LARGE SCALE TROUGH CARVED OUT ACROSS SOUTHEAST
CANADA/GREAT LAKES REGION...FEATURING A SHORTWAVE TROUGH DIVING
INTO NORTHERN MN. VISIBLE SATELLITE CONFIRMS THAT CLOUDY/MOSTLY
CLOUDY SKIES HAVE OVERTAKEN THE ENTIRE CWA...LARGELY A FUNCTION OF
TWO AREAS OF CONVECTION. FIRST...ACROSS COUNTIES GENERALLY ALONG
THE I-80 CORRIDOR...A FAIRLY PERSISTENT EAST-WEST BAND OF ELEVATED
SHOWERS/WEAK STORMS HAS HUNG AROUND NEARLY ALL DAY...AND SEEMS TO
BE LARGELY TIED TO AN AREA OF MID LEVEL CONVERGENCE EVIDENT AROUND
700 MILLIBARS...WITHIN THE ENTRANCE REGION OF AN UPPER JET STREAK
CENTERED DOVER NORTHERN IA/SOUTHERN MN. JUST SOUTH OF THIS ARA OF
CONVECTION...THE BOTTOM TWO ROWS OF NEB COUNTIES HAVE REMAINED
LARGELY DRY THIS AFTERNOON. HOWEVER...ONCE YOU GET TO THE STATE
LINE AND SOUTHWARD INTO KS...AN COMPLETELY SEPARATE AREA OF
SCATTERED CONVECTION HAS BLOSSOMED WITH DAYTIME HEATING...MUCH LIKE
YESTERDAY. THIS CONVECTION HAS FIRED IN RESPONSE TO 1000-2000 J/KG
MLCAPE PER LATEST RUC ANALYSIS IN AN UNCAPPED ENVIRONMENT WITH
STEEP LOW LEVEL LAPSE RATES...BUT WITH FAIRLY POOR MID LEVEL LAPSE
RATES AND ONLY AROUND 20-25 KT OF DEEP LAYER SHEAR. MOST OF THESE
STORMS ARE LIKELY ONLY PRODUCING BRIEF HEAVY RAINS...WIND GUSTS OF
30-40 MPH AND MAYBE SMALL HAIL. DUE TO THE CONVECTION AND VARIABLE
CLOUD COVER...HIGH TEMPS THIS AFTERNOON WERE AN ADVENTURE...AND IN
THE END IT APPEARS MOST OF KS ZONES TOPPED OUT AROUND 90...WITH
MID-UPPER 80S IN SOUTHERN NEB ZONES...BUT ONLY 70S ALONG AND NEAR
THE INTERSTATE 80 CORRIDOR.
TURNING TO THE FORECAST INTO THIS EVENING/TONIGHT...THE BIG
PICTURE ALOFT INVOLVES THE MID LEVEL FLOW TURNING MORE NORTHERLY
OVER THE CWA AND ALSO STARTING TO DRY OUT FROM NORTH-TO-SOUTH IN
RESPONSE TO THE PASSAGE OF THE AFOREMENTIONED GREAT LAKES SHORTWAVE
TROUGH TOWARD EASTERN IA/WI/MI. AS THIS OCCURS...HOWEVER...DECENT
MID LEVEL THETA-E ADVECTION/CONVERGENCE WILL CONTINUE WELL THROUGH
THE NIGHT ESPECIALLY ACROSS SOUTHERN PORTIONS OF THE CWA...AND FOR
SEVERAL HOURS WILL LIKELY SEE A BLEND OF THE DIURNALLY-DRIVEN
AFTERNOON ACTIVITY ALONG WITH ADDITIONAL...SOMEWHAT HIGHER-BASED
ACTIVITY. MEANWHILE...EXPECT THE ACTIVITY NEAR THE I-80 CORRIDOR
TO LARGELY MOVE OUT AND/OR FADE AWAY WITHIN THE NEXT FEW HOURS.
POP-WISE TONIGHT...HAVE A DECENT GRADIENT RANGING FROM ONLY SLIGHT
20S NORTHEAST TO 40S-60S IN SOUTHERN ZONES ESPECIALLY KS. WOULD BE
SURPRISED TO SEE A THREAT OF STRONG STORMS LAST PAST
MIDNIGHT...BUT BETWEEN NOW AND THEN CERTAINLY A FEW COULD WARRANT
SPECIAL WEATHER STATEMENTS. AS FOR LOW TEMPS TONIGHT...MADE ALMOST
NO CHANGE...USING A GUIDANCE BLEND TO AIM FOR UPPER 50S/NEAR 60
NORTH TO UPPER 60S SOUTH. ALTHOUGH SOME PATCHY FOG IS NOT OUT OF
THE QUESTION AS SEEN THIS MORNING...DO NOT THINK IT WILL BE
WIDESPREAD OR VERY IMPACTFUL...SO HAVE OMITTED FROM GRIDS.
FOR THE DAYTIME HOURS THURSDAY 12Z-00Z/7AM-7PM...THE BIG PICTURE
ALOFT INVOLVES THE CWA REMAINING UNDER A TRANSITION ZONE BETWEEN
THE GREAT LAKES SHORTWAVE TROUGH...A RIDGE TO THE SOUTH...AND THE
CLOSED LOW OVER THE INTERMOUNTAIN WEST. FROM THE MID LEVELS DOWN
TO THE LOW LEVELS...INCREASINGLY DRIER AND MORE STABLE AIR WILL
CONTINUE ADVECTING DOWN FROM THE NORTHEAST...WITH THE LOW LEVEL
DRY PUSH EMANATING FROM AN EXPANSIVE SURFACE HIGH SETTLING INTO
THE EASTERN ND/NORTHERN MN AREAS. THERE SHOULD BE A DECENT SKY
COVER GRADIENT BETWEEN MOSTLY SUNNY NORTHEAST TO CLOUDY/MOSTLY
CLOUDY SOUTHWEST...THANKS TO A LINGERING BATCH OF MID LEVEL
SATURATION. UNDER THIS SATURATED LAYER...WILL LIKELY SEE SOME
LINGERING SHOWERS/WEAK STORMS DURING THE DAY MAINLY ACROSS THE
SOUTHWEST 1/4 OF THE CWA...BUT POSSIBLY AS FAR NORTH AS A
GOTHENBURG-HEBRON LINE IN THE MORNING. POPS RANGE FROM ONLY 20-40
PERCENT...AND ITS INTERESTING TO NOTE THAT THE LATEST 4KM WRF-NMM
ACTUALLY SHOWS THE VAST MAJORITY OF THE CWA GOING PRECIP-FREE
AFTER MID-MORNING. AT THE SURFACE...STEADY EAST-NORTHEAST BREEZES
OF 10-15 MPH WILL PREVAIL MOST OF THE DAY...USHERING IN LOWER
DEWPOINTS ONLY IN THE UPPER 40S/LOW 50S IN THE NORTHEAST 1/2 OF
THE CWA...WITH MID 50S TO LOWER 60S SOUTHWEST. ALTHOUGH A
TIGHT SKY COVER GRADIENT COULD MAKE HIGH TEMPS A CHALLENGE...FELT
THAT INCREASING SUNSHINE IN THE NORTHEAST ARGUED FOR SLIGHTLY
WARMER TEMPS...AND IN FACT RAISED NEARLY THE ENTIRE CWA 2-4
DEGREES FROM PREVIOUS BASED ON A GUIDANCE BLEND...WITH MOST AREAS
ENDING UP SOMEWHERE BETWEEN 79-83...OR RIGHT ABOUT NORMAL FOR THE
DATE.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 435 PM CDT WED SEP 11 2013
MAIN CONCERNS IN THE LONG TERM WILL FOCUS ON INTERMITTENT CHANCES
FOR SHOWERS AND THUNDERSTORMS AS WELL AS RESULTING TEMPERATURES
THROUGHOUT THE WEEK.
BY 0Z FRIDAY...THE CENTRAL PLAINS REMAINS ON THE CUSP OF TWO UPPER
LEVEL SYSTEMS...A DEEPENING TROUGH TO THE EAST AND A DEGRADING RIDGE
TO THE WEST. THE CUTOFF LOW ACROSS THE DESERT SOUTHWEST THIS
WEEK...WILL BEGIN TO BECOME INGESTED IN THE UPPER LEVEL
FLOW...THEREBY DEGRADING THE RIDGE AND BRINGING CHANCES FOR SHOWERS
TO THE PLAINS.
PLENTY OF MOISTURE AND UPSLOPE ISENTROPIC FLOW WILL BE ON TAP FRIDAY
MORNING ALONG PORTIONS OF THE FRONT RANGE. HOWEVER...STRONG
NORTHERLY FLOW ON THE BACKSIDE OF THE UPPER TROUGH WILL INTRODUCE A
BATTLE OF DRIER AIR TO THE NORTHEAST AND MOIST AIR TO THE SOUTHWEST.
EXPECTING A TIGHT GRADIENT OF SHOWERS TO FORM WITH THE BULK OF THE
PRECIPITATION REMAINING TO THE SOUTH AND EAST THROUGH FRIDAY MIDDAY.
AS THE RIDGE BREAKS DOWN...SHIFTING THE TROUGH EASTWARD...SHOWERS
SHOULD OVERRIDE THE RIDGE IN THE FORM OF A WARM FRONT INTO AT LEAST
THE NEBRASKA ZONES BY FRIDAY EVENING.
AS CUTOFF LOW BECOMES INGESTED INTO THE MAIN FLOW AND THE FRONT LIFTS
NORTH OVERNIGHT...STALLING OUT ACROSS NORTHERN NEBRASKA...SHOWERS
WILL ALSO LIFT NORTH. WENT AHEAD AND KEPT AT LEAST CHANCE CHANCES
FOR SHOWERS ACROSS THE OUTLOOK AREA THROUGH SATURDAY...ALTHOUGH WITH
LATER MODEL RUNS...THESE SHOWERS MAY END UP BEING SHIFTED A BIT
FURTHER NORTH. HIGH TEMPERATURES ON SATURDAY WILL BE A CONCERN GIVEN
CLOUD COVER AND PRECIPITATION CHANCES AS MUCH OF THE OUTLOOK AREA
WILL BE ON THE SOUTHERN SIDE OF THE WARM FRONT. BUMPED TEMPERATURES
UP A FEW DEGREES...ANTICIPATING A DECENT WARM UP.
A SECONDARY UPPER LEVEL LOW SWINGING ACROSS CANADA WILL HELP DRIVE THE
FRONT BACK THROUGH THE PLAINS IN THE FORM OF A COLD FRONT SATURDAY
EVENING INTO SUNDAY MORNING. THIS WILL LIKELY BE THE BEST SHOT AT
PRECIPITATION AND EVEN THUNDERSTORMS WITH MUCAPE VALUES NEAR 500-750
J/KG.
SHOWERS LINGER THROUGH SUNDAY NIGHT WITH THE BOUNDARY STALLING
ACROSS KANSAS. HEADING INTO THE WORKWEEK...YET ANOTHER UPPER LEVEL
TROUGH WILL BEGIN TO DIVE ACROSS THE WEST COAST. THIS WILL DRIVE AN
UPPER LEVEL SHORT WAVE THROUGH THE REGION. AT THE SURFACE...LOW
PRESSURE ALONG THE FRONT RANGE WILL SLOWLY LIFT THE BOUNDARY AS A
WARM FRONT ACROSS THE OUTLOOK AREA. THUS...WITH LIFT ALONG THIS
FRONTAL BOUNDARY MONDAY NIGHT THROUGH TUESDAY LOOK TO BE WET AS
WELL.
BY MIDWEEK...PREVIOUS RUNS OF THE ECWMF SHOWED A TROUGH OVER THE
REGION...WITH MUCH COOLER 850 MB TEMPERATURES. HOWEVER...THE LATEST
RUN OF THE ECMWF ARE BEGINNING TO COME INTO PHASE WITH THE GFS AND
THE TROUGH REMAINING ACROSS THE WESTERN COAST. THE RIDGE BEGINS TO
BREAKDOWN...HOWEVER...WITH A SHORT WAVE SLIDING ACROSS THE REGION
WEDNESDAY.
AS FOR TEMPERATURES...EXPECT A FAIRLY MILD WEEK AHEAD AS HIGH
TEMPERATURES WILL RANGE FROM 70S TO MID 80S IN MOST AREAS. AS STATED
BEFORE...SATURDAYS HIGH TEMPERATURES COULD EASILY BE WARMER GIVEN
CLOUD COVER AND PRECIPITATION WITH THE FRONTAL BOUNDARY.
TEMPERATURES DIP BACK DOWN INTO THE 70S ON MONDAY WITH THE PASSAGE
OF THE COLD FRONT. THE MIDWEEK WARMS BACK UP...HOWEVER...WITH THE
LIFTING WARM FRONT.
&&
.AVIATION...(FOR THE 18Z KGRI TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1243 PM CDT WED SEP 11 2013
HAVE AIMED FOR VFR CEILING/VISIBILITY THROUGHOUT THE NEXT 24
HOURS...ALTHOUGH THE MAIN CAVEAT WOULD BE IF A BRIEF SHOWER OR
THUNDERSTORM WOULD HAPPEN TO PASS OVERHEAD MAINLY THIS
AFTERNOON/EVENING. SPEAKING OF WHICH...RIGHT OFF THE BAT DURING
THE 1ST HOUR OF THE PERIOD THERE IS A DECENT CHANCE THAT A WEAK
THUNDERSTORM COULD MOVE THROUGH...AND HAVE INTRODUCED A TEMPO GROUP
FOR THIS. BEYOND 19Z...AND THROUGH THE REST OF THE EVENING AND
PART OF THE LATE NIGHT...HAVE MAINTAINED A GENERIC VCTS/VICINITY
THUNDERSTORM MENTION...ALTHOUGH KGRI APPEARS TO BE ON THE NORTHERN
EXTENT OF THUNDERSTORM CHANCES...WITH BETTER CHANCES FOCUSED
50-100 MILES FARTHER SOUTH. BEYOND 09Z THROUGH THE FINAL 9 HOURS
OF THE PERIOD...HAVE DROPPED ALL SHOWER/THUNDERSTORM MENTION AS EVEN
LOW CHANCES SHOULD BE SHUNTED SOUTH OF THE AREA BY THEN PER
LATEST MODELS/GUIDANCE. NOT ACCOUNTING FOR POSSIBLE THUNDERSTORM
OUTFLOW...SURFACE WINDS SHOULD PREVAIL FROM A NORTHEAST DIRECTION
THROUGH THE PERIOD...WITH SPEEDS AVERAGING AROUND 7KT OR LESS INTO
EARLY THURSDAY MORNING...BEFORE PICKING UP A BIT BY LATE MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...SALTZMAN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
344 PM EDT WED SEP 11 2013
.SYNOPSIS...
A WARM AND HUMID AIRMASS WILL REMAIN OVER THE REGION INTO TONIGHT.
A COLD FRONT WILL ARRIVE ACROSS NW OHIO SHORTLY AFTER MIDNIGHT
THEN SWEEP ACROSS THE REGION THROUGH MID MORNING ON THURSDAY.
COOLER AIR WILL SPILL ACROSS THE REGION WITH INCREASING HIGH
PRESSURE. THE HIGH WILL BE EAST OF THE AREA BY SUNDAY MORNING.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
WE HAVE LOCALLY EXPANDED THE WATCH BOX TO COVER THE CURRENT LINE
OF CONVECTION THAT EXTENDS FROM MARION TO MANSFIELD.
TEMPERATURES HAVE WARMED WELL INTO THE 90S ACROSS THE WESTERN HALF
OF THE REGION SO FAR TODAY. THIS HEATING AND SOME CONVERGENCE
ALONG THE COOL POOL FROM EARLY AFTERNOON CONVECTION HAS BEEN
ENOUGH TO TRIGGER THE NEW GROWTH. THE STRONGEST STORMS WILL HAVE
THE CAPABILITY OF PRODUCING STRONG DOWNBURST WINDS. WE SHOULD ALSO
BEGIN TO SEE SOME DEVELOPMENT ACROSS NORTHEAST OHIO INTO NW PA AS
WE WARM A COUPLE MORE DEGREES. STRONG GUSTY WINDS WILL ALSO BE
POSSIBLE WITH THIS CONVECTION.
WE WILL THEN WAIT ON THE COLD FRONT THAT SHOULD MOVE INTO NW OHIO
AFTER MIDNIGHT. THERE COULD BE A FEW ISOLATED THUNDERSTORMS AHEAD
OF THE FRONT BUT WE BELIEVE IT WILL TAKE THE STRONGER FORCING
ALONG THE FRONT TO PRODUCE MOST OF THE OVERNIGHT ACTIVITY.
IT WILL BE ANOTHER WARM AND HUMID NIGHT FOR THE REGION. NW OHIO
WILL COOL IN THE WAKE OF THE FRONT BUT IT WILL BE LATE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY NIGHT/...
THE COLD FRONT WILL BE MOVING ACROSS THE REGION THROUGH THE MORNING
WITH SHOWERS AND SOME SCATTERED THUNDER EXPECTED NEAR AND AHEAD OF
THE FRONT. THERE WILL BE A LULL IN THE SHOWERS FOR A FEW HOURS
THURSDAY AFTERNOON INTO THE EVENING. AS THE COOLER AIR SPILLS INTO
THE AREA THURSDAY NIGHT AND AN UPPER LEVEL TROUGH PASSES WE SHOULD
SEE AN INCREASE IN LAKE EFFECT SHOWERS. THESE LAKE EFFECT SHOWERS
WILL CONTINUE INTO FRIDAY AND MAY END BY EARLY SATURDAY MORNING.
DAYTIME HIGHS ON THURSDAY WILL BE IN THE MORNING AND MAY HOLD
STEADY OR DROP SLIGHTLY THROUGH THE AFTERNOON. MUCH COOLER FRIDAY
INTO SATURDAY WITH HIGHS LIKELY REMAINING IN THE 60S. A FEW
LOCATIONS MAY STAY IN THE 50S ACROSS NW PA ON FRIDAY.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
THE MODELS INDICATE ANOTHER COLD FRONT THAT MOVES SE ACROSS THE AREA
EARLY SUN NIGHT. MOISTURE SOMEWHAT LIMITED SO WILL ONLY CARRY A
CHANCE POP FOR SHRA WITH THE FRONTAL PASSAGE. WINDS TURN BACK TO THE
NORTH FOR MON BRINGING DRIER AND COOLER AIR BACK INTO THE AREA.
THERE COULD BE A LINGERING SHRA IN THE SE IN THE MORNING...OTHERWISE
SHOULD SEE DRY CONDITIONS TAKE OVER AND HOLD ON UNTIL TUE NIGHT OR
WED WHEN A WARM FRONT MAY BE LIFTING NEAR THE AREA ALONG WITH
INCREASING MOISTURE. THE MODELS DIFFER BY WED ON HOW MUCH MOISTURE
MAKES ITS WAY BACK INTO THE AREA SO WILL ONLY CARRY A SLIGHT CHANCE
POP FOR NOW.
TEMPS SHOULD BE NEAR NORMAL FOR SUN THEN DROP BACK BELOW NORMAL MON
AND TUE BEFORE MODERATING BACK TO NEAR NORMAL BY WED.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
MID LEVEL CLOUD HAD BEEN HELPING TO KEEP TSRA FROM DEVELOPING.
BASED ON LATEST MODEL RUNS AND RADAR DATA...STILL EXPECT SCT TSRA
OVER MAINLY THE SE THIRD OF THE AREA THIS AFTERNOON. HRRR AND RUC
STILL INDECISIVE ON TIME AND LOCATION OF POTENTIAL TSRA REST OF
TODAY...THUS DON`T HAVE MUCH CONFIDENCE IN ANYTHING AT ANY TAF
SITES THRU 00Z SO WILL LIKELY JUST MENTION VCTS UNLESS SOMETHING
LOOKS IMMINENT AT TAF ISSUE TIME.
OUTSIDE OF ANY SHRA/TSRA...SHOULD SEE VFR/HIGH END MVFR TEND TO
PREVAIL AT MOST SITES UNTIL LATE TONIGHT AND FRI MORNING WHEN PRECIP
SHOULD BECOME MORE WIDESPREAD THEN WINDS START TO TURN NW TO ALLOW
LOWER CLOUDS TO MOVE IN OFF OF LAKE ERIE.
OUTLOOK...WILL LIKELY HAVE NON VFR CEILINGS ACROSS NE OH/NW PA LATE
THURSDAY THROUGH FRIDAY.
&&
.MARINE...
MODELS STILL INDICATE A SW FLOW AT ABOUT 10 TO 20 KNOTS TONIGHT
UNTIL A COLD FRONT DROPS ACROSS THE LAKE AROUND DAYBREAK THU TO
SHIFT THE FLOW TO NNW. THE PRESSURE GRADIENT TIGHTENS BY LATER THU
SO WINDS SHOULD PICK UP TO 15 TO 20 KNOTS AND MAYBE 15 TO 25 KNOTS.
WAVES WILL BUILD TO 4 TO 6 FEET SO A SCA WILL BE NEEDED AND WILL
LIKELY LAST UNTIL LATE FRI NIGHT WHEN HIGH PRESSURE FINALLY BUILDS
INTO THE LAKE TO DIMINISH THE FLOW.
THE HIGH WILL PRODUCE LIGHT AND CHANGEABLE FLOW SAT INTO SAT NIGHT
THEN WINDS LINE UP OUT OF THE SW FOR SUN AND LOOK TO INCREASE TO 10
TO 15 KNOTS. ANOTHER COLD FRONT WILL MOVE ACROSS THE LAKE LATER SUN
OR SUN NIGHT TO SHIFT THE FLOW BACK TO NORTH FOR MON AND MAY PRODUCE
NEAR SCA CONDITIONS.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MULLEN
NEAR TERM...MULLEN
SHORT TERM...MULLEN
LONG TERM...ADAMS
AVIATION...ADAMS
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
101 PM EDT WED SEP 11 2013
.SYNOPSIS...
A COLD FRONT LOCATED FROM NORTHERN MICHIGAN TO EASTERN IOWA THIS
MORNING WILL MOVE SOUTH TODAY...REACHING NORTHERN OH/NW PA
THURSDAY MORNING. A SECONDARY TROUGH WILL MOVE THROUGH THURSDAY
AFTERNOON. A SIGNIFICANT AIRMASS CHANGE WILL TAKE PLACE...WITH
TEMPERATURES TURNING FROM ABOVE NORMAL HEAT TO A BELOW NORMAL
CHILL FOR FRIDAY INTO THE WEEKEND. HIGH PRESSURE WILL BE OVER THE
REGION SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE GONE WITH SCATTERED THUNDERSTORMS ACROSS THE AREA FOR THE
AFTERNOON. THE BEST CHANCES LOOK TO BE ACROSS THE EASTERN THIRD OF
THE REGION. WE WILL THEN WATCH FOR ADDITIONAL CONVECTION TO MOVE
INTO THE WEST DURING THE EVENING HOURS.
THE SEVERE POTENTIAL HAS INCREASED SLIGHTLY ACROSS THE EASTERN
THIRD OF THE REGION WHERE DEEPER MOISTURE AND SOME WEAK MIDDLE
LEVEL FORCING SEEMS TO EXIST. THIS FORCING IS EVIDENT BY THE
MORNING SHOWERS/THUNDERSTORMS THAT DEVELOPED NEAR AND EAST OF A
LINE FROM ERIE TO DAYTON. AS WE HEAT A BIT MORE THIS AFTERNOON
THE THREAT OF STRONG DAMAGING WINDS WILL INCREASE.
PREVIOUS DISCUSSION...
A NUMBER OF ITEMS TO CONSIDER FOR TODAY. STRONG RIDGE OVER THE
OHIO VALLEY WILL BEGIN TO BREAK DOWN. A FRONTAL SYSTEM OVER THE
CENTRAL GREAT LAKES WILL BEGIN TO MAKE PROGRESS SOUTH...ALTHOUGH
SLOW AT FIRST. ONE INITIAL SHORTWAVE SHEARS OFF TO NEW ENGLAND
BRINGING THE FRONT INTO CENTRAL LOWER MI FOR THIS AFTERNOON. A
STRONGER SHORTWAVE COMING OUT OF SOUTH CENTRAL CANADA WILL CARVE
OUT THE TROUGH FOR THE GREAT LAKES AND GIVE THAT FRONT A PUSH
SOUTH OVERNIGHT. FIRST QUESTION BECOMES HOW MUCH IN THE WAY OF
SHOWERS/STORMS DO WE GET BEFORE 6P. AN AREA OF DEEPER MOISTURE
THAT 24 HRS AGO WAS NEAR PADUCAH IS NOW ACROSS SOUTHWEST OHIO.
MODEL GUIDANCE SHOWERS THAT A FEW SHOWERS/TS INITIATE WITH THIS
ACROSS OUR SOUTHEAST COUNTIES INCLUDING YOUNGSTOWN AND
AKRON/CANTON. HAVE FOCUSED SOME AFTERNOON PRECIP CHANCES THERE.
ALSO A LITTLE CONCERNED WITH AREA FROM FINDLAY TO MANSFIELD FOR AN
ISOLATED STORM. FINALLY SOME PREFRONTAL ACTIVITY IS POSSIBLE
ACROSS SE MI AND THEREFORE ALSO THE TOLEDO AREA. SPC SLIGHT RISK
IS ACROSS THE NORTHERN HALF OF THE AREA FOR STORMS LATE THIS
AFTERNOON AND EVENING. AGREE WITH THAT. NEXT QUESTION IS
TEMPERATURES. THE ONLY THING SAVING US FROM A REPEAT OF YESTERDAY
IS THE PRESENCE OF ADDITIONAL CLOUD COVER. THIS MAY BE JUST ENOUGH
TO KEEP US OUT OF HEAT ADVISORY TERRITORY. UPPER 80S ACROSS THE
SOUTHEAST TO LOWER 90S ACROSS THE I-75 CORRIDOR.
ONLY MINOR SKY COVER ADJUSTMENTS WERE MADE WITH THIS EARLY MORNING
UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
SO STRONGER SHORTWAVE THAT WILL AMPLIFY THE TROUGH ACROSS THE
GREAT LAKES WILL PUSH THE COLD FRONT SOUTH TONIGHT. AT 6 PM STORMS
MAY BE ONGOING ACROSS FAR NW OH OR BE CLOSE BY. SOME CONCERN FOR
SEVERE STORMS ESPECIALLY ACROSS THE LAKESHORE COUNTIES. WIND WOULD
BE THE PRIMARY THREAT. AREA WILL BECOME MODESTLY UNSTABLE AND
SHEAR WILL BEGIN TO INCREASE AS THE UPPER TROUGH APPROACHES. WILL
JUST HAVE TO WATCH FRONTAL TIMING AND ANY PREFRONTAL AREAS OF
CONVERGENCE. MARCH LIKELY AND CATEGORICAL PRECIP CHANCES SOUTHWARD
OVER THE COURSE OF THE NIGHT AND INTO THURSDAY MORNING.
CONTINUED PRECIPITATION CHANCES INTO MUCH OF THURSDAY. THERE ARE
INDICATIONS OF A SECONDARY TROUGH THAT MAY AID IN A FEW ADDITIONAL
SHOWERS/TS. THE COLD PUSH WITH THIS SYSTEM IS SLIGHTLY
DELAYED...AND IS ASSOCIATED MORE WITH THE SECONDARY TROUGH. SO
THURSDAY WILL TURN OUT NEAR NORMAL FOR HIGHS. THE BIG CHANGE COMES
FOR FRIDAY.
WHILE THERE MAY BE A LULL IN PRECIPITATION THURSDAY EVENING...AS
THE COLDER AIR FILTERS IN AND THE UPPER TROUGH APPROACHES...LAKE
EFFECT CONDITIONS BEGIN TO TAKE SHAPE. SCATTERED SHOWERS STARTING
LATE THURSDAY NIGHT AND CONTINUING INTO FRIDAY POSSIBLE. HAVE
RAISED POPS ACROSS NRN OH/NW PA. ALSO HAVE ADDED THE MENTION OF
ISOLATED THUNDER FOR EAST OF CLEVELAND. LAKE TO H5 TEMPERATURE
DIFFERENCE GREAT ENOUGH FOR THE POSSIBILITY OF THUNDER WITHIN THE
LAKE EFFECT SHOWERS. TEMPERATURES FRIDAY WILL STRUGGLE TO GET INTO
THE 60S...WITH SOME PARTS OF NW PA/FAR NE OH STAYING IN THE UPPER
50S.
LAKE EFFECT SHOWERS SHOULD BE CONFINED TO FRIDAY AND MAYBE FRIDAY
NIGHT. AFTER THAT RIDGING AND DRYING BEGIN TO WORK INTO THE AREA
ENDING THAT THREAT. TEMPS FRIDAY NIGHT TO BE IN THE 40S. WITH
CLEARING ACROSS THE WEST TEMPS WILL BE CLOSER TO 40. SATURDAY
HIGHS SIMILAR..60 TO 65. BY SATURDAY NIGHT MORE OF THE AREA WILL
BE CLEARER AND MORE LOWER 40S ARE EXPECTED. IT IS DEFINITELY
POSSIBLE TO GET UPPER 30S DEPENDING ON CLOUD COVER.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THIS PORTION OF THE EXTENDED DOES NOT LOOK VERY ACTIVE. HIGH
PRESSURE WILL BE MOVING EAST ON SUNDAY AND THAT WILL ALLOW A COLD
FRONT TO MOVE IN SUNDAY NIGHT INTO MONDAY BEFORE HIGH PRESSURE
BUILDS BACK IN. THE 00Z GFS AND ECMWF NOW AGREE WITH THIS SOLUTION.
AT THIS TIME KEPT THE POPS AROUND 20%. THIS MAY HAVE TO BE RAISED
SOME IF THE TREND REMAINS THE SAME. KEPT CLOSE TO HPC GUIDANCE FOR
THE TEMPERATURE FORECAST WHICH HAS SLIGHTLY BELOW NORMAL
TEMPERATURES.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
MID LEVEL CLOUD HAD BEEN HELPING TO KEEP TSRA FROM DEVELOPING. BASED
ON LATEST MODEL RUNS AND RADAR DATA...STILL EXPECT SCT TSRA OVER
MAINLY THE SE THIRD OF THE AREA THIS AFTERNOON. HRRR AND RUC STILL
INDECISIVE ON TIME AND LOCATION OF POTENTIAL TSRA REST OF
TODAY...THUS DON`T HAVE MUCH CONFIDENCE IN ANYTHING AT ANY TAF SITES
THRU 00Z SO WILL LIKELY JUST MENTION VCTS UNLESS SOMETHING LOOKS
IMMINENT AT TAF ISSUE TIME.
OUTSIDE OF ANY SHRA/TSRA...SHOULD SEE VFR/HIGH END MVFR TEND TO
PREVAIL AT MOST SITES UNTIL LATE TONIGHT AND FRI MORNING WHEN PRECIP
SHOULD BECOME MORE WIDESPREAD THEN WINDS START TO TURN NW TO ALLOW
LOWER CLOUDS TO MOVE IN OFF OF LAKE ERIE.
OUTLOOK...WILL LIKELY HAVE NON VFR CEILINGS ACROSS NE OH/NW PA LATE
THURSDAY THROUGH FRIDAY.
&&
.MARINE...
SOME ACTIVE WEATHER FOR THE LAKE WILL BEGIN ESPECIALLY TONIGHT AND
LAST INTO FRIDAY. SOUTHWEST WINDS ON THE LAKE TODAY WILL STAY BELOW
SMALL CRAFT ADVISORY CONDITIONS EVEN ON THE EAST END. THE COLD FRONT
WILL MOVE ACROSS THE LAKE LATE TONIGHT AND EARLY THURSDAY MORNING.
SOME OF THE THUNDERSTORMS AHEAD OF THE FRONT WILL LIKELY PROMPT
SPECIAL MARINE WARNINGS TO BE ISSUED.
SOME QUESTION HOW QUICKLY THE WINDS WILL PICK UP ON THE LAKE
THURSDAY BEHIND THE COLD FRONT. WENT TOWARD THE FASTER GFS IN
INCREASING THE WINDS ESPECIALLY ON THE EAST END AND THEN THE WEST
END THURSDAY NIGHT. EVENTUALLY A SMALL CRAFT ADVISORY WILL BE NEEDED
ON MUCH OF LAKE ERIE. THE THREAT FOR A SMALL CRAFT ADVISORY
CONDITIONS WILL LAST INTO FRIDAY NIGHT. PLENTY OF COLD AIR WILL BE
FLOWING ACROSS THE LAKE AND THAT MAY GENERATE SOME WATERSPOUTS AND
THUNDER BESIDES THE SHOWERS ESPECIALLY ON FRIDAY AS THE LAKE AND 850
MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C AND THE LAKE AND 500 MB
TEMPERATURE DIFFERENCE WILL BE AROUND 40C.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SATURDAY AND THEN MOVE
EAST ON SUNDAY ALLOWING THE SOUTHWEST FLOW TO RETURN. A FRONT WILL
CROSS THE LAKE SUNDAY NIGHT INTO MONDAY SHIFTING THE WINDS TO
ONSHORE AS THE HIGH WILL TRY TO BUILD IN. THE WINDS AND WAVES ARE
EXPECTED TO BE BELOW SMALL CRAFT ADVISORY CONDITIONS EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...ADAMS
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1214 PM EDT WED SEP 11 2013
.SYNOPSIS...
A COLD FRONT LOCATED FROM NORTHERN MICHIGAN TO EASTERN IOWA THIS
MORNING WILL MOVE SOUTH TODAY...REACHING NORTHERN OH/NW PA
THURSDAY MORNING. A SECONDARY TROUGH WILL MOVE THROUGH THURSDAY
AFTERNOON. A SIGNIFICANT AIRMASS CHANGE WILL TAKE PLACE...WITH
TEMPERATURES TURNING FROM ABOVE NORMAL HEAT TO A BELOW NORMAL
CHILL FOR FRIDAY INTO THE WEEKEND. HIGH PRESSURE WILL BE OVER THE
REGION SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE GONE WITH SCATTERED THUNDERSTORMS ACROSS THE AREA FOR THE
AFTERNOON. THE BEST CHANCES LOOK TO BE ACROSS THE EASTERN THIRD OF
THE REGION. WE WILL THEN WATCH FOR ADDITIONAL CONVECTION TO MOVE
INTO THE WEST DURING THE EVENING HOURS.
THE SEVERE POTENTIAL HAS INCREASED SLIGHTLY ACROSS THE EASTERN
THIRD OF THE REGION WHERE DEEPER MOISTURE AND SOME WEAK MIDDLE
LEVEL FORCING SEEMS TO EXIST. THIS FORCING IS EVIDENT BY THE
MORNING SHOWERS/THUNDERSTORMS THAT DEVELOPED NEAR AND EAST OF A
LINE FROM ERIE TO DAYTON. AS WE HEAT A BIT MORE THIS AFTERNOON
THE THREAT OF STRONG DAMAGING WINDS WILL INCREASE.
PREVIOUS DISCUSSION...
A NUMBER OF ITEMS TO CONSIDER FOR TODAY. STRONG RIDGE OVER THE
OHIO VALLEY WILL BEGIN TO BREAK DOWN. A FRONTAL SYSTEM OVER THE
CENTRAL GREAT LAKES WILL BEGIN TO MAKE PROGRESS SOUTH...ALTHOUGH
SLOW AT FIRST. ONE INITIAL SHORTWAVE SHEARS OFF TO NEW ENGLAND
BRINGING THE FRONT INTO CENTRAL LOWER MI FOR THIS AFTERNOON. A
STRONGER SHORTWAVE COMING OUT OF SOUTH CENTRAL CANADA WILL CARVE
OUT THE TROUGH FOR THE GREAT LAKES AND GIVE THAT FRONT A PUSH
SOUTH OVERNIGHT. FIRST QUESTION BECOMES HOW MUCH IN THE WAY OF
SHOWERS/STORMS DO WE GET BEFORE 6P. AN AREA OF DEEPER MOISTURE
THAT 24 HRS AGO WAS NEAR PADUCAH IS NOW ACROSS SOUTHWEST OHIO.
MODEL GUIDANCE SHOWERS THAT A FEW SHOWERS/TS INITIATE WITH THIS
ACROSS OUR SOUTHEAST COUNTIES INCLUDING YOUNGSTOWN AND
AKRON/CANTON. HAVE FOCUSED SOME AFTERNOON PRECIP CHANCES THERE.
ALSO A LITTLE CONCERNED WITH AREA FROM FINDLAY TO MANSFIELD FOR AN
ISOLATED STORM. FINALLY SOME PREFRONTAL ACTIVITY IS POSSIBLE
ACROSS SE MI AND THEREFORE ALSO THE TOLEDO AREA. SPC SLIGHT RISK
IS ACROSS THE NORTHERN HALF OF THE AREA FOR STORMS LATE THIS
AFTERNOON AND EVENING. AGREE WITH THAT. NEXT QUESTION IS
TEMPERATURES. THE ONLY THING SAVING US FROM A REPEAT OF YESTERDAY
IS THE PRESENCE OF ADDITIONAL CLOUD COVER. THIS MAY BE JUST ENOUGH
TO KEEP US OUT OF HEAT ADVISORY TERRITORY. UPPER 80S ACROSS THE
SOUTHEAST TO LOWER 90S ACROSS THE I-75 CORRIDOR.
ONLY MINOR SKY COVER ADJUSTMENTS WERE MADE WITH THIS EARLY MORNING
UPDATE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
SO STRONGER SHORTWAVE THAT WILL AMPLIFY THE TROUGH ACROSS THE
GREAT LAKES WILL PUSH THE COLD FRONT SOUTH TONIGHT. AT 6 PM STORMS
MAY BE ONGOING ACROSS FAR NW OH OR BE CLOSE BY. SOME CONCERN FOR
SEVERE STORMS ESPECIALLY ACROSS THE LAKESHORE COUNTIES. WIND WOULD
BE THE PRIMARY THREAT. AREA WILL BECOME MODESTLY UNSTABLE AND
SHEAR WILL BEGIN TO INCREASE AS THE UPPER TROUGH APPROACHES. WILL
JUST HAVE TO WATCH FRONTAL TIMING AND ANY PREFRONTAL AREAS OF
CONVERGENCE. MARCH LIKELY AND CATEGORICAL PRECIP CHANCES SOUTHWARD
OVER THE COURSE OF THE NIGHT AND INTO THURSDAY MORNING.
CONTINUED PRECIPITATION CHANCES INTO MUCH OF THURSDAY. THERE ARE
INDICATIONS OF A SECONDARY TROUGH THAT MAY AID IN A FEW ADDITIONAL
SHOWERS/TS. THE COLD PUSH WITH THIS SYSTEM IS SLIGHTLY
DELAYED...AND IS ASSOCIATED MORE WITH THE SECONDARY TROUGH. SO
THURSDAY WILL TURN OUT NEAR NORMAL FOR HIGHS. THE BIG CHANGE COMES
FOR FRIDAY.
WHILE THERE MAY BE A LULL IN PRECIPITATION THURSDAY EVENING...AS
THE COLDER AIR FILTERS IN AND THE UPPER TROUGH APPROACHES...LAKE
EFFECT CONDITIONS BEGIN TO TAKE SHAPE. SCATTERED SHOWERS STARTING
LATE THURSDAY NIGHT AND CONTINUING INTO FRIDAY POSSIBLE. HAVE
RAISED POPS ACROSS NRN OH/NW PA. ALSO HAVE ADDED THE MENTION OF
ISOLATED THUNDER FOR EAST OF CLEVELAND. LAKE TO H5 TEMPERATURE
DIFFERENCE GREAT ENOUGH FOR THE POSSIBILITY OF THUNDER WITHIN THE
LAKE EFFECT SHOWERS. TEMPERATURES FRIDAY WILL STRUGGLE TO GET INTO
THE 60S...WITH SOME PARTS OF NW PA/FAR NE OH STAYING IN THE UPPER
50S.
LAKE EFFECT SHOWERS SHOULD BE CONFINED TO FRIDAY AND MAYBE FRIDAY
NIGHT. AFTER THAT RIDGING AND DRYING BEGIN TO WORK INTO THE AREA
ENDING THAT THREAT. TEMPS FRIDAY NIGHT TO BE IN THE 40S. WITH
CLEARING ACROSS THE WEST TEMPS WILL BE CLOSER TO 40. SATURDAY
HIGHS SIMILAR..60 TO 65. BY SATURDAY NIGHT MORE OF THE AREA WILL
BE CLEARER AND MORE LOWER 40S ARE EXPECTED. IT IS DEFINITELY
POSSIBLE TO GET UPPER 30S DEPENDING ON CLOUD COVER.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THIS PORTION OF THE EXTENDED DOES NOT LOOK VERY ACTIVE. HIGH
PRESSURE WILL BE MOVING EAST ON SUNDAY AND THAT WILL ALLOW A COLD
FRONT TO MOVE IN SUNDAY NIGHT INTO MONDAY BEFORE HIGH PRESSURE
BUILDS BACK IN. THE 00Z GFS AND ECMWF NOW AGREE WITH THIS SOLUTION.
AT THIS TIME KEPT THE POPS AROUND 20%. THIS MAY HAVE TO BE RAISED
SOME IF THE TREND REMAINS THE SAME. KEPT CLOSE TO HPC GUIDANCE FOR
THE TEMPERATURE FORECAST WHICH HAS SLIGHTLY BELOW NORMAL TEMPERATURES.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE BIG QUESTION IS THE TIMING OF THE THUNDERSTORMS FOR TODAY AND
TONIGHT. IN THE MEANTIME INCREASING MID AND HIGH CLOUDS FOR THE
MORNING. ANY FOG WILL DISSIPATE BY MID MORNING BUT SOME HAZE COULD
CONTINUE INTO THE AFTERNOON.
THE MODELS ARE FAIRLY CONSISTENT IN INCREASING THE LOW LEVEL
MOISTURE BY MID TO LATE MORNING OVER NE OH AND NW PA AND THEN
DEVELOPING SCATTERED SHOWERS AND THUNDERSTORMS. THIS IS OK...EVEN
THOUGH THE HRRR MODEL HAS BACKED DOWN ON THIS. AT THIS TIME JUST KEPT
IT THUNDER VICINITY. A LITTLE BREAK MAY OCCUR EARLY THIS EVENING
OVER NE OH AND NW PA WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING OVER NW OH AND SPREADING EAST AND THEN A BETTER CHANCE
OF SHOWERS AND THUNDERSTORMS AFTER MIDNIGHT AS THE FRONT
APPROACHES.
OUTLOOK...WILL LIKELY HAVE NON VFR CEILINGS ACROSS NE OH/NW PA
THURSDAY THROUGH FRIDAY.
&&
.MARINE...
SOME ACTIVE WEATHER FOR THE LAKE WILL BEGIN ESPECIALLY TONIGHT AND
LAST INTO FRIDAY. SOUTHWEST WINDS ON THE LAKE TODAY WILL STAY BELOW
SMALL CRAFT ADVISORY CONDITIONS EVEN ON THE EAST END. THE COLD FRONT
WILL MOVE ACROSS THE LAKE LATE TONIGHT AND EARLY THURSDAY MORNING.
SOME OF THE THUNDERSTORMS AHEAD OF THE FRONT WILL LIKELY PROMPT
SPECIAL MARINE WARNINGS TO BE ISSUED.
SOME QUESTION HOW QUICKLY THE WINDS WILL PICK UP ON THE LAKE
THURSDAY BEHIND THE COLD FRONT. WENT TOWARD THE FASTER GFS IN
INCREASING THE WINDS ESPECIALLY ON THE EAST END AND THEN THE WEST
END THURSDAY NIGHT. EVENTUALLY A SMALL CRAFT ADVISORY WILL BE NEEDED
ON MUCH OF LAKE ERIE. THE THREAT FOR A SMALL CRAFT ADVISORY
CONDITIONS WILL LAST INTO FRIDAY NIGHT. PLENTY OF COLD AIR WILL BE
FLOWING ACROSS THE LAKE AND THAT MAY GENERATE SOME WATERSPOUTS AND
THUNDER BESIDES THE SHOWERS ESPECIALLY ON FRIDAY AS THE LAKE AND 850
MB TEMPERATURE DIFFERENCE WILL BE NEAR 20C AND THE LAKE AND 500 MB
TEMPERATURE DIFFERENCE WILL BE AROUND 40C.
HIGH PRESSURE WILL BUILD OVER THE LAKE ON SATURDAY AND THEN MOVE
EAST ON SUNDAY ALLOWING THE SOUTHWEST FLOW TO RETURN. A FRONT WILL
CROSS THE LAKE SUNDAY NIGHT INTO MONDAY SHIFTING THE WINDS TO
ONSHORE AS THE HIGH WILL TRY TO BUILD IN. THE WINDS AND WAVES ARE
EXPECTED TO BE BELOW SMALL CRAFT ADVISORY CONDITIONS EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA