Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 04/04/12


AREA FORECAST DISCUSSION
NWS PUEBLO CO
400 PM MDT MON APR 2 2012 .SHORT TERM... (TONIGHT AND TUESDAY) ...STRONG SPRING STORM TAKING AIM ON SOUTH CENTRAL AND SOUTHEAST COLORADO... MODELS IN REMARKABLE AGREEMENT WITH THE OVERALL DETAILS OF CLOSED UPPER LOW ACROSS EAST CENTRAL NEW MEXICO SHIFTING EASTWARD THEN NORTHEASTWARD INTO THE TX/OK PANHANDLE BY TUES AFTERNOON. FRONT HAS ALREADY SLAMMED THROUGH EASTERN CO EARLIER TODAY...WITH PEAK GUSTS IN EXCESS OF 60 MPH ACROSS PORTIONS OF EL PASO COUNTY. HRRR AND LOCAL 4 KM WRF INDICATED TWO PERIODS OF STRONGER WINDS...ONE THIS MORNING...AND ANOTHER THIS AFTERNOON INTO EARLY THIS EVENING. JUST PICKED UP A GUST TO 50 KTS AT KPUB AIRPORT AROUND 230 PM...SO PERHAPS THE SHORT RANGE MODELS DO HAVE A HANDLE ON THIS. THUS...WILL MAINTAIN HIGH WIND WARNINGS THROUGH 03Z. INTERESTINGLY...HRRR SUGGESTS CORE OF STRONGER WINDS MAY EXPAND ACROSS MORE OF THE SOUTHEAST PLAINS AND CONTINUE THROUGH 06Z...HOWEVER WITH TIGHTEST PRESSURE GRADIENT ALREADY PAST...WILL LEAVE CURRENT EXPIRATION AT 03Z AND LET LATER SHIFTS MONITOR THE TRENDS TO DECIDE IF EXTENSION IN TIME...OR EXPANSION IN AREA IS NECESSARY. LOCAL 4 KM WRF BACKED OFF SOME ON WIND GUSTS AFTER 03Z FOR ALL BUT PERHAPS EASTERN EL PASO COUNTY. OTHER AREA OF CONCERN FOR HIGH WINDS CONTINUES ALONG THE EASTERN SIDE OF THE SAN LUIS VALLEY AS WINDS ACCELERATE THROUGH THE PASSES IN THE SANGRES AND SPILLS INTO THE VALLEY. HRRR AND 12Z 4KM WRF STILL PAINT THIS SCENARIO IN THE LATEST RUNS...WITH PEAK WINDS OCCURRING NOW THROUGH 00Z...WITH GUSTS STARTING TO TAIL OFF BY 03Z. ALS HAD A WIND GUST TO 54 MPH AFTER NOON...WHICH IS VERY CLOSE. SUSPECT LOCAL AREAS TO THE WEST HAD HIGHER GUSTS. AGAIN...WRF KEEPS GUSTS UP AROUND 70 MPH THROUGH 03Z BEFORE TAILING OFF...SO CURRENT HIGHLIGHT LOOKS ON TARGET. FIRST LOBE OF ENERGY WILL ROTATE AROUND THE CLOSED LOW INTO SOUTHEAST COLORADO THIS EVENING. SNOW IS ALREADY OCCURRING ACROSS THE EAST FACING SLOPES OF THE SANGRES/WETS...THOUGH ITS BEEN PRETTY LIGHT SO FAR AS MOISTURE LAYER REMAINS SHALLOW. HOWEVER...RADARS TO THE SOUTH SHOW ECHOES EXPANDING ACROSS NORTHEAST NM WITH SOME EMBEDDED CONVECTION EVIDENT VIA LIGHTNING STRIKES. SHOULD SEE THIS BAND OF SHOWERS SPREAD NORTHWARD THROUGH THE EVENING WITH SNOW SPREADING NORTHWARD AND RAMPING UP ACROSS THE PIKES PEAK AREA AFTER 03-06Z. NICE ISENTROPIC UPGLIDE EVIDENT IN BOTH NAM AND GFS ON THE 300K SFC...AND MODELS IN GOOD AGREEMENT WITH HEAVY QPF AMOUNTS ACROSS A LARGE PORTION OF THE SOUTHEAST PLAINS THROUGH TUESDAY...PARTICULARLY NEAR THE MOUNTAINS. SNOW LEVELS WILL START OFF AROUND 7000 FEET...BUT DROP TO AROUND 5000 FEET OVERNIGHT. TIMING OF THE DROP IN TEMPERATURES AND THE RESIDUAL WARMTH OF THE GROUND WILL PLAY A BIG ROLE IN HOW MUCH SNOW ACCUMULATES ACROSS THE LOWER ELEVATIONS OF THE I-25 CORRIDOR SUCH AS SOUTHERN EL PASO AND PUEBLO COUNTIES. HOWEVER...WITH GOOD MODEL CONSENSUS AND IMPRESSIVE TROWAL ALOFT EXPECTED TO OVERWHELM DOWNSLOPE OFF THE PALMER AT LEAST THROUGH THE 06Z TO 15Z WINDOW...HAVE OPTED TO ISSUE A WINTER WEATHER ADVISORY FOR THE LOWER ELEVATIONS OF THE I-25 CORRIDOR...INCLUDING COLORADO SPRINGS AND PUEBLO. SNOWFALL AMOUNTS WILL LIKELY EXHIBIT A WIDE RANGE WITH SOME MELTING OFF ROAD SURFACES AT TIMES...BUT ANYWHERE FROM 2 INCHES ON THE GRASS...TO AROUND 6 INCHES NEAR THE MOUNTAINS SEEMS PLAUSIBLE. WITH A PERIOD OF EAST TO NORTHEAST WINDS FUNNELING UP THE ARKANSAS RIVER...AND UPSLOPING ALONG THE WEST SIDE OF THE LA GARITAS/AND EASTERN SAN JUANS...WILL INCLUDE THESE AREAS IN A WINTER WEATHER ADVISORY AND RUN IT THROUGH 00Z. BIGGEST WINNER IN THIS EVENT WILL BE THE EAST SLOPES OF THE SANGRES AND WETS 40 TO 50 KTS OF NORTHEAST UPSLOPE WILL RESULT IN 1 TO 2 FEET OF SNOW...WITH HIGHER AMOUNTS ( UP TO 30 INCHES) ACROSS THE HIGHER ELEVATIONS. REMAINDER OF THE HEADLINES IN GOOD SHAPE. TROWAL EVENTUALLY PULLS OFF TO THE NORTHEAST ON TUESDAY WITH SNOW WINDING DOWN FROM SOUTHWEST TO NORTHEAST DURING THE DAY ON TUESDAY. -KT .LONG TERM... (TUESDAY NIGHT-MONDAY) ...TIMING AND LOCATION OF UPPER LEVEL STORM LIFTING OUT ACROSS THE SE PLAINS TUESDAY NIGHT THE MAIN FORECAST PROBLEM... TUESDAY NIGHT-WEDNESDAY...SLIGHT MODEL DIFFERENCES ON TIMING AND LOCATION OF UPPER LOW LIFTING OUT ACROSS THE SE PLAINS CONTINUE AND HAVE TAILORED FORECAST TOWARDS THE NAM AND EC WHICH HAVE THE LOW ACROSS EXTREME NORTHEAST NEW MEXICO AT 00Z WED AND THEN SLOWLY LIFT IT OUT ACROSS WESTERN OKLAHOMA INTO CENTRAL OKLAHOMA THROUGH THE DAY ON WEDNESDAY. ONGOING WRAP AROUND PRECIPITATION ACROSS THE EASTERN MTS AND I-25 CORRIDOR TUESDAY AFTERNOON SLOWLY SHIFTS EAST AND DIMINISHES FROM WEST TO EAST OVERNIGHT...AS UPPER LEVEL FLOW BECOMES MORE NORTHWEST. COULD SEE SOME ADDITIONAL LIGHT ACCUMULATIONS OF A COUPLE OF INCHES ACROSS THE NORTH AND EAST FACING SLOPES OF THE EASTERN MTS AND ALONG WITH PALMER DVD AND RATON MESA TUESDAY EVENING WITH THINGS WINDING INTO WEDNESDAY MORNING. TEMPERATURES ALOFT WARM FROM WEST TO EAST THROUGH THE DAY ON WEDNESDAY...AS UPPER LEVEL RIDGING BUILDS INTO THE STATE WITH HIGHS WARMING BACK TO AT OR SLIGHTLY ABOVE SEASONAL AVERAGES...THOUGH HAVE TAPERED BACK HIGHS A TAD IN EXPECTED SNOW COVERED AREAS. WEDNESDAY NIGHT-MONDAY...WARMER AND DRIER WEATHER CONTINUES TO BE PROGGED THROUGH THE PERIOD...WITH MODERATE TO STRONG WESTERLY FLOW EXPECTED ACROSS THE REGION AS SEVERAL SHORT WAVES MOVE ACROSS THE NORTHERN ROCKIES. ONE WAVE MOVES ACROSS THE REGION THURSDAY NIGHT AND FRIDAY...WITH BREEZY TO WINDY CONDITIONS AND POSSIBLE CRITICAL FIRE WEATHER CONDITIONS ON FRIDAY...DEPENDING ON HOW MUCH PRECIP FALLS. PASSING WAVE SENDS A DRY COLD FRONT ACROSS THE PLAINS FRIDAY WITH SLIGHTLY COOLER TEMPERATURES ACROSS THE AREA ON SATURDAY. ANOTHER WAVE POSSIBLE MOVES ACROSS THE NORTHERN ROCKIES ON SUNDAY NIGHT...WITH A BACKDOOR COLD FRONT POSSIBLE BRINGING IN ENOUGH LOW LEVEL MOISTURE FOR A FEW SHOWERS ACROSS THE EASTERN PLAINS ON MONDAY. HOWEVER...WILL KEEP A DRY FORECAST IN TACT THROUGH THE PERIOD. -MW && .AVIATION... IFR CIGS/VIS EXPECTED TO AFFECT THE TAF SITES TONIGHT AS STRONG SYSTEM MOVES ACROSS NORTHERN NEW MEXICO. STRONG NORTH WINDS IN THE 30 TO 45 KT RANGE WILL CONTINUE AT KCOS AND KPUB BEFORE DECREASING TOWARDS 06Z. KALS WILL CONTINUE TO SEE EAST WINDS IN THE 25 TO 40 KT RANGE THROUGH EARLY EVENING WITH PERIODS OF BLDU. HEAVIEST SNOW WILL IMPACT KCOS AND KPUB BETWEEN 06Z-18Z PERIOD WITH POTENTIAL FOR A COUPLE INCHES OF SNOW...MAINLY ON GRASSY SURFACES AT KPUB...TO AROUND 2 TO 5 INCHES AT KCOS. WITH WARM GROUND...THERE WILL BE SOME MELTING AT TIMES AT KCOS...BUT PAVED SURFACES COULD BECOME SLUSHY AND SNOWPACKED UNDER THE HEAVIER SNOW BANDS. KALS COULD SEE AN INCH OR TWO AS WELL. RAIN/SNOW SWITCH OVER WILL OCCUR AROUND 03Z FOR KCOS AND KALS...AND AROUND 06Z FOR KPUB. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ069>071- 084>086-089-093. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT TUESDAY FOR COZ078-087-088. WINTER STORM WARNING UNTIL 6 PM MDT TUESDAY FOR COZ072>075-079- 080. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 PM MDT TUESDAY FOR COZ058-060>063-076-077. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON MDT TUESDAY FOR COZ083-085-086. WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MDT TUESDAY FOR COZ066>068. WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 PM MDT TUESDAY FOR COZ081-082-084. && $$ 31/23
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1136 AM MDT MON APR 2 2012 .AVIATION... STRONG WINTER STORM WILL CONTINUE AFFECTING THE REGION THROUGH EARLY WEDNESDAY. AT KCOS AND KPUB...STRONG NORTHERLY WINDS WILL CONTINUE THROUGH AT LEAST MIDDAY TUESDAY..WITH A MODEST DECREASE IN WIND SPEEDS MONDAY EVENING. ISENTROPIC UPGLIDE WILL BE STRONG ENOUGH TONIGHT TO OVERCOME THE DOWNGLIDE RESULTING FROM THE STRONG NORTHERLY WINDS. TAFS HAVE SNOW WITH IFR CEILINGS AND VISIBILITIES FROM MONDAY EVENING THROUGH AROUND 12Z TUESDAY. ACCUMULATIONS OF 2 TO 5 INCHES ARE FORECAST FOR KCOS. AT KPUB ACCUMULATIONS WILL BE LIMITED TO AN INCH OR TWO ON GRASSY SURFACES. AFTER 12Z TUESDAY...DOWNGLIDE FROM STRONG NORTHERLY WINDS WILL LIMIT PRECIPITATION AT KCOS AND KPUB. HOWEVER...HEAVY PRECIPITATION IS LIKELY NORTH OF KCOS AND SOUTH OF KPUB. AT KALS...STRONG EASTERLY WINDS WILL WEAKEN DURING THE EVENING. UPPER LEVEL FORCING SHOULD BE STRONG ENOUGH TO PRODUCE SNOW AT KALS OVERNIGHT...WITH CHANCES FOR SNOW DECREASING AFTER 12Z TUESDAY. --PGW-- && .PREV DISCUSSION... /ISSUED 1017 AM MDT MON APR 2 2012/ UPDATE... LATEST HRRR AND LOCAL 4 KM WRF ALSO SHOWING ANOTHER INCREASE IN THE WIND GUSTS LATER THIS AFTERNOON THROUGH THIS EVENING ALONG/SOUTH OF THE PALMER DIVIDE. THUS WILL BE EXTENDING THE HIGH WIND WARNING THROUGH 03Z. -KT PREV DISCUSSION... /ISSUED 1007 AM MDT MON APR 2 2012/ UPDATE... HIGH RES MODELS...HRRR...LOCAL 4 KM WRF ALL POINTING TO POTENTIAL HIGH WIND EVENT FOR THE EASTERN PORTIONS OF THE SAN LUIS VALLEY WHERE EASTERLY WINDS WILL POUR THROUGH THE GAPS AND VALLEYS OF THE SANGRES. GIVEN THE STRONG PRESSURE GRADIENT BEHIND THE FRONT...THIS SEEMS PLAUSIBLE...AND HAVE PUT OUT A HIGH WIND WARNING FOR THE SAN LUIS VALLEY TO ACCOUNT FOR THIS. HRRR AND LOCAL 4 KM WRF ALL INDICATE POTENTIAL FOR GUSTS IN EXCESS OF 60 TO EVEN 70 MPH. SUSPECT THIS WILL BE FAIRLY LOCALIZED TO THE EASTERN FRINGES OF THE SAN LUIS VALLEY. HIGH WIND WARING ALREADY OUT. UPDATED GRIDS AND FORECAST TO FOLLOW SHORTLY. -KT PREV DISCUSSION... /ISSUED 428 AM MDT MON APR 2 2012/ SHORT TERM... (TODAY AND TONIGHT) MAJOR SPRING STORM TO AFFECT OUR AREA... IRONICALLY...IT LOOKS LIKE THE BIGGEST STORM OF THIS SEASON WILL COME IN SPRING THIS YEAR. A STRONG COLD FRONT HAS ALREADY MOVED THROUGH THE NRN TIER OF OUR CWA THIS MORN..WITH GUSTS TO 40 KT ALREADY BEING REPORTED AT KCOS. THESE WINDS WILL CONTINUE TO INCREASE THROUGH THE MORNING HOURS...WITH SUSTAINED WINDS OF 30-40 KT LIKELY AND SOME GUSTS IN THE 50-60 KT RANGE POSSIBLE. WILL CONTINUE THE HIGH WIND WARNING...AND EXTEND THROUGH THIS AFTERNOON AS IT NOW LOOKS LIKE SUSTAINED WINDS COULD MEET HIGH WIND CRITERIA FOR AT LEAST SOME OF THIS AREA THROUGH THE DAY. STILL SEEING VERY DRY AND MILD CONDITIONS ACROSS THE PLAINS. TEMPS HAVE BEEN CLIMBING STEADILY AT KPUB WITH FRONTAL SUBSIDENCE. DEWPOINTS ARE RISING CONSIDERABLY BEHIND THE FRONT...BUT REAL MOIST AIR WILL HOLD OFF TIL LATER TODAY. SKIES ARE STILL CLR THIS MORN AND LOW CLOUDS IN THE SAT FOG PRODUCT ARE CONFINED TO NW CO ATTM. HAVE SEEN CONTINUED LIGHT-MDT ECHOES OVR WRN CO ALL MORNING...AND WHILE OBS ARE RATHER DEVOID OF PRECIP...SUSPECT THE HIGHER PEAKS ARE SEEING SOME PRECIP THIS MORN. THE FRONT WILL SET THE STAGE FOR A VERY DYNAMIC SYSTEM THAT IS NOW MOVING INTO THE 4 CORNERS REGION. THIS SYSTEM WILL CONTINUE TO STRONGLY INTENSIFY AS A VERY STRONG MID LEVEL JET STREAK MOVES THROUGH SRN NM. THE UPPER LOW WILL TRACK JUST S OF KABQ THIS AFTERNOON...AS A CLASSIC AND INFAMOUS `ALBUQUERQUE LOW`. WILL SEE TEMPS HOLD STEADY OR FALL LATER TODAY AS COLD AIR CONTINUES TO POUR IN BEHIND THE FRONT...AND H7 TEMPS FALL TO MINUS 8 TO MINUS 10 BY THIS EVE. MAIN ACTION WITH THIS STORM WILL BE TONIGHT...AS THE JET BEGINS TO ROUND THE TROUGH BASE AND THE UPPER LOW MAKE A MOVE TO THE NE. THIS IS THE TRACK THAT HAS BEEN FAVORED BY THE GFS AND ECMWF FOR THE LAST COUPLE OF DAYS...AND THE NAM HAS FINALLY CAUGHT ON TO THIS SOLUTION IN A BIG WAY. TIMING WILL BE PERFECT FOR A HEAVY SNOW EVENT...ESPECIALLY OVER THE HIGHER ELEVATIONS...AND COULD EVEN SEE SOME SNOW AT THE LOWER ELEVATIONS DUE TO THE FAVORABLE OVERNIGHT TIMING AND PRIMED CONDITIONS. WET BULB ZERO WILL FALL STEADILY FROM AROUND 6500 FT TODAY TO AS LOW AS 4500 FEET TONIGHT. EXPECT THAT MOST LOCATIONS ABOVE 6000 FEET...INCLUDING KCOS...WILL SEE SOME SNOW. OF COURSE...WITH VERY WARM GROUND MUCH OF THE EARLY SNOWFALL WILL FAIL TO ACCUMULATE INITIALLY...BUT WITH A GOOD 8-12 H PERIOD OF SNOW COULD SEE SOME LIGHT ACCUMS FOR THE I-25 CORRIDOR. KCOS LOOKS TO BE SOLIDLY BELOW FZG FOR THE MAIN EVENT...AS THE TROWAL REALLY KICKS IN FROM 03Z TO 12Z OVERNIGHT. ANY PRECIP BEFORE 03Z WILL LIKELY BE RAIN OR A RN/SN MIX. N WINDS MAY LIMIT PRECIP FOR S EL PASO AND N PUEBLO COUNTIES...BUT VERY STRONG ISENTROPIC LIFT MAY OVERCOME SOME OF THE DOWNSLOPE DRYING EFFECT. AS FOR `WINTER` HEADLINES...HAVE CONVERTED OUR WATCH TO A WARNING...AND ADDED THE WET MOUNTAIN VALLEY AS WELL. WOULD NOT BE SURPRISED TO SEE IN EXCESS OF 2 FEET FOR THE HIGHEST ELEVATIONS OF THE WETS/SANGRES...IF CURRENT PROGS PAN OUT AS EXPECTED. RATON PASS WILL BE PARTICULARLY PROBLEMATIC TONIGHT AND TUE AS STRONG N WINDS COMBINE WITH SN TO PRODUCE WHITE OUT CONDITIONS AT TIMES. CONSIDERED UPGRADING TO A BLIZZARD WARNING FOR THE RATON...BUT CURRENTLY DOES NOT LOOK LIKE WINDS WILL BE SUSTAINED LONG ENOUGH...AND HEAVIEST PRECIP OCCURS AFTER THE STRONGEST WINDS. HOWEVER...WILL NEED TO WATCH THIS AREA CLOSELY. ALSO HAVE INTRODUCED A WINTER STORM WATCH FOR TELLER AND N EL PASO FOR TONIGHT AND TUE. COULD GET PRETTY NASTY OVER MONUMENT HILL BY TUE. HOPEFULLY THIS STORM WILL PUT A DENT IN THE DROUGHT. LET IT SNOW! 44 LONG TERM... (TUESDAY - SUNDAY) BENEFICIAL PRECIP AT THE BEGINNING OF THE PD THEN DRYING OUT AGAIN... MODELS IN THE EARLY PART OF THIS FCST PD HAVE COME INTO GOOD AGREEMENT BRINGING THE CUTOFF LOW NORTHEASTWARD ACROSS SE CO. BY 12Z TUESDAY...SNOW AND RAIN SHOULD BE ONGOING ACROSS A GOOD PART OF THE REGION...WITH THE BEST CHANCE OF PRECIP OVER THE EAST FACING SLOPES OF THE MTNS ADJ TO THE PLAINS...AND THE RATON MESA AND PALMER DVD REGIONS. THE RAIN/SNOW LINE AT 12Z WILL LIKELY BE AROUND 5000 FEET. FOR THE MORNING RUSH HOUR...SNOW WILL LIKELY NOT ACCUMULATE MUCH ON ROAD SURFACES BETWEEN 5000 AND 6500 FEET...BUT ANYTHING ABOVE 6500 FEET WILL LIKELY BECOME SLUSHY. GRASSY SFCS BETWEEN THE AFOREMENTIONED ELEVATIONS WILL LIKELY ACCUMULATE SOME SNOW...SO THE PUEBLO AREA MAY SEE AN INCH OF MEASURABLE SNOW. OVERALL...TWO TO THREE INCHES OF SNOW WILL LIKELY OCCUR ACROSS THE EASTERN MTNS/RATON MESA AND PALMER DVD...WITH LOCALLY HEAVY ACCUMS ACROSS PIKES PEAK AND THE HIGHER ELEVATIONS OF THE EAST SLOPES OF THE WETS/SANGRES. BY MIDDAY TUESDAY...THE LOW CENTER ALOFT WILL LIKELY BE IN THE SE CO AREA AND 700 MB FLOW WILL BECOME MORE NORTHERLY ACROSS THE WETS/SANGRES. THIS SHOULD ALLOW THE SNOW TO DECREASE ACROSS THESE REGIONS AS THE FLOW WILL NOT BE AS FAVORABLE...BUT FARTHER NORTH ACROSS THE GREATER PIKES PEAK REGION MODEST NE 700 MB FLOW WILL BE ONGOING. LIKEWISE...THE PALMER DVD REGION AND RAMPARTS/PIKES PEAK WILL LIKELY SEE SNOW CONTINUING. THE RAIN/SNOW LINE SHOULD INCREASE A BIT DURING THE DAY...BUT NOT BY MUCH. BY LATE IN THE DAY TUESDAY THE RAIN/SNOW SHOULD PRETTY MUCH BE OVER ACROSS THE PLAINS...HOWEVER BOTH NAM/GFS SHOW WRAP AROUND PRECIP CONTINUING OVER THE HIGHER TRRN OF THE MTNS..ESPECIALLY THE SANGRES AND SAN JUANS. FOR THIS REASON I HAVE INCREASED POPS OVER THESE REGIONS DURING THIS TIME. NOTE THAT THE WINTER STORM WARNING FOR THE SANGRES EXPIRES AT 00Z WED. IF THE MODELS ARE CORRECT...THIS WARNING MAY NEED TO BE EXTENDED FOR THIS MTN RANGE BY ABOUT 6 HOURS OR SO. AS FOR HIGH TEMPERATURES ON TUESDAY...I HAVE DECREASED THEM...WITH TEMPS REACHING ABOUT 40F ALONG THE I-25 CORRIDOR REGION...AND THESE VALUES MAY BE A BIT TOO HIGH IF THE MODEL SOUNDINGS ARE CORRECT. OVER THE FAR E PLAINS AND SAN LUIS VALLEY...HIGHS SHOULD BE ABOUT 50F. AS FOR THE REST OF THE FCST...WE WILL BE RETURNING TO A DRY PATTERN AGAIN AS SW FLOW GRADUALLY RAMPS UP ONCE AGAIN. IF WE DO GET AS MUCH PRECIP AS THE MODELS ARE INDICATING...THEN FIRE WX CONCERNS SHOULD DROP SIGNIFICANTLY ACROSS THE FCST AREA. ATTM...THE WARMEST TEMPS SHOULD BE DURING THE FRI-SAT TIME FRAME WITH A DRY PAC FRONT COMING ACROSS THE REGION SAT NITE. TEMPS WILL COOL AGAIN ON SUNDAY. THE NEXT CHANCE OF PRECIP...ACCORDING TO THE GFS WILL BE MONDAY...BUT THE EC SIMULATION IS DRY FROM WED THROUGH NEXT WEEK. /34 AVIATION... STRONG N WINDS BEHIND A COLD FRONT WILL CONTINUE TO AFFECT KCOS AND KPUB THROUGH THE NEXT 6-12 H. SUSTAINED WINDS FORM 30-40 KTS WITH HIGHER GUSTS WILL BE POSSIBLE. WINDS WILL GRADUALLY DIMINISH THIS EVE...HOWEVER...PRECIP IS EXPECTED TO BECOME MORE LIKELY OVERNIGHT...WITH A GOOD CHANE OF SN AT KCOS AND A RAIN-SNOW MIX POSSIBLE AT KPUB LATER TONIGHT. ALONG WITH GUSTY WINDS VIS IS EXPECTED TO BE LOW OVERNIGHT IN PARTICULAR. KALS WILL ALSO SEE GUSTY NE WINDS AND THE CHANCE OF SOME SHSN...BUT THE WORST CONDITIONS WILL BE ALONG AND W OF I-25. 44 && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ069>071- 084>086-089-093. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT TUESDAY FOR COZ078-087-088. WINTER STORM WARNING UNTIL 6 PM MDT TUESDAY FOR COZ072>075-079- 080. WINTER STORM WATCH FROM 9 PM MDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR COZ081-082-084. && $$ 06/06
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
1017 AM MDT MON APR 2 2012 .UPDATE... LATEST HRRR AND LOCAL 4 KM WRF ALSO SHOWING ANOTHER INCREASE IN THE WIND GUSTS LATER THIS AFTERNOON THROUGH THIS EVENING ALONG/SOUTH OF THE PALMER DIVIDE. THUS WILL BE EXTENDING THE HIGH WIND WARNING THROUGH 03Z. -KT && .PREV DISCUSSION... /ISSUED 1007 AM MDT MON APR 2 2012/ UPDATE... HIGH RES MODELS...HRRR...LOCAL 4 KM WRF ALL POINTING TO POTENTIAL HIGH WIND EVENT FOR THE EASTERN PORTIONS OF THE SAN LUIS VALLEY WHERE EASTERLY WINDS WILL POUR THROUGH THE GAPS AND VALLEYS OF THE SANGRES. GIVEN THE STRONG PRESSURE GRADIENT BEHIND THE FRONT...THIS SEEMS PLAUSIBLE...AND HAVE PUT OUT A HIGH WIND WARNING FOR THE SAN LUIS VALLEY TO ACCOUNT FOR THIS. HRRR AND LOCAL 4 KM WRF ALL INDICATE POTENTIAL FOR GUSTS IN EXCESS OF 60 TO EVEN 70 MPH. SUSPECT THIS WILL BE FAIRLY LOCALIZED TO THE EASTERN FRINGES OF THE SAN LUIS VALLEY. HIGH WIND WARING ALREADY OUT. UPDATED GRIDS AND FORECAST TO FOLLOW SHORTLY. -KT PREV DISCUSSION... /ISSUED 428 AM MDT MON APR 2 2012/ SHORT TERM... (TODAY AND TONIGHT) .MAJOR SPRING STORM TO AFFECT OUR AREA... IRONICALLY...IT LOOKS LIKE THE BIGGEST STORM OF THIS SEASON WILL COME IN SPRING THIS YEAR. A STRONG COLD FRONT HAS ALREADY MOVED THROUGH THE NRN TIER OF OUR CWA THIS MORN..WITH GUSTS TO 40 KT ALREADY BEING REPORTED AT KCOS. THESE WINDS WILL CONTINUE TO INCREASE THROUGH THE MORNING HOURS...WITH SUSTAINED WINDS OF 30-40 KT LIKELY AND SOME GUSTS IN THE 50-60 KT RANGE POSSIBLE. WILL CONTINUE THE HIGH WIND WARNING...AND EXTEND THROUGH THIS AFTERNOON AS IT NOW LOOKS LIKE SUSTAINED WINDS COULD MEET HIGH WIND CRITERIA FOR AT LEAST SOME OF THIS AREA THROUGH THE DAY. STILL SEEING VERY DRY AND MILD CONDITIONS ACROSS THE PLAINS. TEMPS HAVE BEEN CLIMBING STEADILY AT KPUB WITH FRONTAL SUBSIDENCE. DEWPOINTS ARE RISING CONSIDERABLY BEHIND THE FRONT...BUT REAL MOIST AIR WILL HOLD OFF TIL LATER TODAY. SKIES ARE STILL CLR THIS MORN AND LOW CLOUDS IN THE SAT FOG PRODUCT ARE CONFINED TO NW CO ATTM. HAVE SEEN CONTINUED LIGHT-MDT ECHOES OVR WRN CO ALL MORNING...AND WHILE OBS ARE RATHER DEVOID OF PRECIP...SUSPECT THE HIGHER PEAKS ARE SEEING SOME PRECIP THIS MORN. THE FRONT WILL SET THE STAGE FOR A VERY DYNAMIC SYSTEM THAT IS NOW MOVING INTO THE 4 CORNERS REGION. THIS SYSTEM WILL CONTINUE TO STRONGLY INTENSIFY AS A VERY STRONG MID LEVEL JET STREAK MOVES THROUGH SRN NM. THE UPPER LOW WILL TRACK JUST S OF KABQ THIS AFTERNOON...AS A CLASSIC AND INFAMOUS `ALBUQUERQUE LOW`. WILL SEE TEMPS HOLD STEADY OR FALL LATER TODAY AS COLD AIR CONTINUES TO POUR IN BEHIND THE FRONT...AND H7 TEMPS FALL TO MINUS 8 TO MINUS 10 BY THIS EVE. MAIN ACTION WITH THIS STORM WILL BE TONIGHT...AS THE JET BEGINS TO ROUND THE TROUGH BASE AND THE UPPER LOW MAKE A MOVE TO THE NE. THIS IS THE TRACK THAT HAS BEEN FAVORED BY THE GFS AND ECMWF FOR THE LAST COUPLE OF DAYS...AND THE NAM HAS FINALLY CAUGHT ON TO THIS SOLUTION IN A BIG WAY. TIMING WILL BE PERFECT FOR A HEAVY SNOW EVENT...ESPECIALLY OVER THE HIGHER ELEVATIONS...AND COULD EVEN SEE SOME SNOW AT THE LOWER ELEVATIONS DUE TO THE FAVORABLE OVERNIGHT TIMING AND PRIMED CONDITIONS. WET BULB ZERO WILL FALL STEADILY FROM AROUND 6500 FT TODAY TO AS LOW AS 4500 FEET TONIGHT. EXPECT THAT MOST LOCATIONS ABOVE 6000 FEET...INCLUDING KCOS...WILL SEE SOME SNOW. OF COURSE...WITH VERY WARM GROUND MUCH OF THE EARLY SNOWFALL WILL FAIL TO ACCUMULATE INITIALLY...BUT WITH A GOOD 8-12 H PERIOD OF SNOW COULD SEE SOME LIGHT ACCUMS FOR THE I-25 CORRIDOR. KCOS LOOKS TO BE SOLIDLY BELOW FZG FOR THE MAIN EVENT...AS THE TROWAL REALLY KICKS IN FROM 03Z TO 12Z OVERNIGHT. ANY PRECIP BEFORE 03Z WILL LIKELY BE RAIN OR A RN/SN MIX. N WINDS MAY LIMIT PRECIP FOR S EL PASO AND N PUEBLO COUNTIES...BUT VERY STRONG ISENTROPIC LIFT MAY OVERCOME SOME OF THE DOWNSLOPE DRYING EFFECT. AS FOR `WINTER` HEADLINES...HAVE CONVERTED OUR WATCH TO A WARNING...AND ADDED THE WET MOUNTAIN VALLEY AS WELL. WOULD NOT BE SURPRISED TO SEE IN EXCESS OF 2 FEET FOR THE HIGHEST ELEVATIONS OF THE WETS/SANGRES...IF CURRENT PROGS PAN OUT AS EXPECTED. RATON PASS WILL BE PARTICULARLY PROBLEMATIC TONIGHT AND TUE AS STRONG N WINDS COMBINE WITH SN TO PRODUCE WHITE OUT CONDITIONS AT TIMES. CONSIDERED UPGRADING TO A BLIZZARD WARNING FOR THE RATON...BUT CURRENTLY DOES NOT LOOK LIKE WINDS WILL BE SUSTAINED LONG ENOUGH...AND HEAVIEST PRECIP OCCURS AFTER THE STRONGEST WINDS. HOWEVER...WILL NEED TO WATCH THIS AREA CLOSELY. ALSO HAVE INTRODUCED A WINTER STORM WATCH FOR TELLER AND N EL PASO FOR TONIGHT AND TUE. COULD GET PRETTY NASTY OVER MONUMENT HILL BY TUE. HOPEFULLY THIS STORM WILL PUT A DENT IN THE DROUGHT. LET IT SNOW! 44 LONG TERM... (TUESDAY - SUNDAY) .BENEFICIAL PRECIP AT THE BEGINNING OF THE PD THEN DRYING OUT AGAIN... MODELS IN THE EARLY PART OF THIS FCST PD HAVE COME INTO GOOD AGREEMENT BRINGING THE CUTOFF LOW NORTHEASTWARD ACROSS SE CO. BY 12Z TUESDAY...SNOW AND RAIN SHOULD BE ONGOING ACROSS A GOOD PART OF THE REGION...WITH THE BEST CHANCE OF PRECIP OVER THE EAST FACING SLOPES OF THE MTNS ADJ TO THE PLAINS...AND THE RATON MESA AND PALMER DVD REGIONS. THE RAIN/SNOW LINE AT 12Z WILL LIKELY BE AROUND 5000 FEET. FOR THE MORNING RUSH HOUR...SNOW WILL LIKELY NOT ACCUMULATE MUCH ON ROAD SURFACES BETWEEN 5000 AND 6500 FEET...BUT ANYTHING ABOVE 6500 FEET WILL LIKELY BECOME SLUSHY. GRASSY SFCS BETWEEN THE AFOREMENTIONED ELEVATIONS WILL LIKELY ACCUMULATE SOME SNOW...SO THE PUEBLO AREA MAY SEE AN INCH OF MEASURABLE SNOW. OVERALL...TWO TO THREE INCHES OF SNOW WILL LIKELY OCCUR ACROSS THE EASTERN MTNS/RATON MESA AND PALMER DVD...WITH LOCALLY HEAVY ACCUMS ACROSS PIKES PEAK AND THE HIGHER ELEVATIONS OF THE EAST SLOPES OF THE WETS/SANGRES. BY MIDDAY TUESDAY...THE LOW CENTER ALOFT WILL LIKELY BE IN THE SE CO AREA AND 700 MB FLOW WILL BECOME MORE NORTHERLY ACROSS THE WETS/SANGRES. THIS SHOULD ALLOW THE SNOW TO DECREASE ACROSS THESE REGIONS AS THE FLOW WILL NOT BE AS FAVORABLE...BUT FARTHER NORTH ACROSS THE GREATER PIKES PEAK REGION MODEST NE 700 MB FLOW WILL BE ONGOING. LIKEWISE...THE PALMER DVD REGION AND RAMPARTS/PIKES PEAK WILL LIKELY SEE SNOW CONTINUING. THE RAIN/SNOW LINE SHOULD INCREASE A BIT DURING THE DAY...BUT NOT BY MUCH. BY LATE IN THE DAY TUESDAY THE RAIN/SNOW SHOULD PRETTY MUCH BE OVER ACROSS THE PLAINS...HOWEVER BOTH NAM/GFS SHOW WRAP AROUND PRECIP CONTINUING OVER THE HIGHER TRRN OF THE MTNS..ESPECIALLY THE SANGRES AND SAN JUANS. FOR THIS REASON I HAVE INCREASED POPS OVER THESE REGIONS DURING THIS TIME. NOTE THAT THE WINTER STORM WARNING FOR THE SANGRES EXPIRES AT 00Z WED. IF THE MODELS ARE CORRECT...THIS WARNING MAY NEED TO BE EXTENDED FOR THIS MTN RANGE BY ABOUT 6 HOURS OR SO. AS FOR HIGH TEMPERATURES ON TUESDAY...I HAVE DECREASED THEM...WITH TEMPS REACHING ABOUT 40F ALONG THE I-25 CORRIDOR REGION...AND THESE VALUES MAY BE A BIT TOO HIGH IF THE MODEL SOUNDINGS ARE CORRECT. OVER THE FAR E PLAINS AND SAN LUIS VALLEY...HIGHS SHOULD BE ABOUT 50F. AS FOR THE REST OF THE FCST...WE WILL BE RETURNING TO A DRY PATTERN AGAIN AS SW FLOW GRADUALLY RAMPS UP ONCE AGAIN. IF WE DO GET AS MUCH PRECIP AS THE MODELS ARE INDICATING...THEN FIRE WX CONCERNS SHOULD DROP SIGNIFICANTLY ACROSS THE FCST AREA. ATTM...THE WARMEST TEMPS SHOULD BE DURING THE FRI-SAT TIME FRAME WITH A DRY PAC FRONT COMING ACROSS THE REGION SAT NITE. TEMPS WILL COOL AGAIN ON SUNDAY. THE NEXT CHANCE OF PRECIP...ACCORDING TO THE GFS WILL BE MONDAY...BUT THE EC SIMULATION IS DRY FROM WED THROUGH NEXT WEEK. /34 AVIATION... STRONG N WINDS BEHIND A COLD FRONT WILL CONTINUE TO AFFECT KCOS AND KPUB THROUGH THE NEXT 6-12 H. SUSTAINED WINDS FORM 30-40 KTS WITH HIGHER GUSTS WILL BE POSSIBLE. WINDS WILL GRADUALLY DIMINISH THIS EVE...HOWEVER...PRECIP IS EXPECTED TO BECOME MORE LIKELY OVERNIGHT...WITH A GOOD CHANE OF SN AT KCOS AND A RAIN-SNOW MIX POSSIBLE AT KPUB LATER TONIGHT. ALONG WITH GUSTY WINDS VIS IS EXPECTED TO BE LOW OVERNIGHT IN PARTICULAR. KALS WILL ALSO SEE GUSTY NE WINDS AND THE CHANCE OF SOME SHSN...BUT THE WORST CONDITIONS WILL BE ALONG AND W OF I-25. 44 && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ069>071- 084>086-089-093. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT TUESDAY FOR COZ078-087-088. WINTER STORM WARNING UNTIL 6 PM MDT TUESDAY FOR COZ072>075-079- 080. WINTER STORM WATCH FROM 9 PM MDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR COZ081-082-084. && $$ 31/23
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1007 AM MDT MON APR 2 2012 .UPDATE... HIGH RES MODELS...HRRR...LOCAL 4 KM WRF ALL POINTING TO POTENTIAL HIGH WIND EVENT FOR THE EASTERN PORTIONS OF THE SAN LUIS VALLEY WHERE EASTERLY WINDS WILL POUR THROUGH THE GAPS AND VALLEYS OF THE SANGRES. GIVEN THE STRONG PRESSURE GRADIENT BEHIND THE FRONT...THIS SEEMS PLAUSIBLE...AND HAVE PUT OUT A HIGH WIND WARNING FOR THE SAN LUIS VALLEY TO ACCOUNT FOR THIS. HRRR AND LOCAL 4 KM WRF ALL INDICATE POTENTIAL FOR GUSTS IN EXCESS OF 60 TO EVEN 70 MPH. SUSPECT THIS WILL BE FAIRLY LOCALIZED TO THE EASTERN FRINGES OF THE SAN LUIS VALLEY. HIGH WIND WARING ALREADY OUT. UPDATED GRIDS AND FORECAST TO FOLLOW SHORTLY. -KT && .PREV DISCUSSION... /ISSUED 428 AM MDT MON APR 2 2012/ SHORT TERM... (TODAY AND TONIGHT) ..MAJOR SPRING STORM TO AFFECT OUR AREA... IRONICALLY...IT LOOKS LIKE THE BIGGEST STORM OF THIS SEASON WILL COME IN SPRING THIS YEAR. A STRONG COLD FRONT HAS ALREADY MOVED THROUGH THE NRN TIER OF OUR CWA THIS MORN..WITH GUSTS TO 40 KT ALREADY BEING REPORTED AT KCOS. THESE WINDS WILL CONTINUE TO INCREASE THROUGH THE MORNING HOURS...WITH SUSTAINED WINDS OF 30-40 KT LIKELY AND SOME GUSTS IN THE 50-60 KT RANGE POSSIBLE. WILL CONTINUE THE HIGH WIND WARNING...AND EXTEND THROUGH THIS AFTERNOON AS IT NOW LOOKS LIKE SUSTAINED WINDS COULD MEET HIGH WIND CRITERIA FOR AT LEAST SOME OF THIS AREA THROUGH THE DAY. STILL SEEING VERY DRY AND MILD CONDITIONS ACROSS THE PLAINS. TEMPS HAVE BEEN CLIMBING STEADILY AT KPUB WITH FRONTAL SUBSIDENCE. DEWPOINTS ARE RISING CONSIDERABLY BEHIND THE FRONT...BUT REAL MOIST AIR WILL HOLD OFF TIL LATER TODAY. SKIES ARE STILL CLR THIS MORN AND LOW CLOUDS IN THE SAT FOG PRODUCT ARE CONFINED TO NW CO ATTM. HAVE SEEN CONTINUED LIGHT-MDT ECHOES OVR WRN CO ALL MORNING...AND WHILE OBS ARE RATHER DEVOID OF PRECIP...SUSPECT THE HIGHER PEAKS ARE SEEING SOME PRECIP THIS MORN. THE FRONT WILL SET THE STAGE FOR A VERY DYNAMIC SYSTEM THAT IS NOW MOVING INTO THE 4 CORNERS REGION. THIS SYSTEM WILL CONTINUE TO STRONGLY INTENSIFY AS A VERY STRONG MID LEVEL JET STREAK MOVES THROUGH SRN NM. THE UPPER LOW WILL TRACK JUST S OF KABQ THIS AFTERNOON...AS A CLASSIC AND INFAMOUS `ALBUQUERQUE LOW`. WILL SEE TEMPS HOLD STEADY OR FALL LATER TODAY AS COLD AIR CONTINUES TO POUR IN BEHIND THE FRONT...AND H7 TEMPS FALL TO MINUS 8 TO MINUS 10 BY THIS EVE. MAIN ACTION WITH THIS STORM WILL BE TONIGHT...AS THE JET BEGINS TO ROUND THE TROUGH BASE AND THE UPPER LOW MAKE A MOVE TO THE NE. THIS IS THE TRACK THAT HAS BEEN FAVORED BY THE GFS AND ECMWF FOR THE LAST COUPLE OF DAYS...AND THE NAM HAS FINALLY CAUGHT ON TO THIS SOLUTION IN A BIG WAY. TIMING WILL BE PERFECT FOR A HEAVY SNOW EVENT...ESPECIALLY OVER THE HIGHER ELEVATIONS...AND COULD EVEN SEE SOME SNOW AT THE LOWER ELEVATIONS DUE TO THE FAVORABLE OVERNIGHT TIMING AND PRIMED CONDITIONS. WET BULB ZERO WILL FALL STEADILY FROM AROUND 6500 FT TODAY TO AS LOW AS 4500 FEET TONIGHT. EXPECT THAT MOST LOCATIONS ABOVE 6000 FEET...INCLUDING KCOS...WILL SEE SOME SNOW. OF COURSE...WITH VERY WARM GROUND MUCH OF THE EARLY SNOWFALL WILL FAIL TO ACCUMULATE INITIALLY...BUT WITH A GOOD 8-12 H PERIOD OF SNOW COULD SEE SOME LIGHT ACCUMS FOR THE I-25 CORRIDOR. KCOS LOOKS TO BE SOLIDLY BELOW FZG FOR THE MAIN EVENT...AS THE TROWAL REALLY KICKS IN FROM 03Z TO 12Z OVERNIGHT. ANY PRECIP BEFORE 03Z WILL LIKELY BE RAIN OR A RN/SN MIX. N WINDS MAY LIMIT PRECIP FOR S EL PASO AND N PUEBLO COUNTIES...BUT VERY STRONG ISENTROPIC LIFT MAY OVERCOME SOME OF THE DOWNSLOPE DRYING EFFECT. AS FOR `WINTER` HEADLINES...HAVE CONVERTED OUR WATCH TO A WARNING...AND ADDED THE WET MOUNTAIN VALLEY AS WELL. WOULD NOT BE SURPRISED TO SEE IN EXCESS OF 2 FEET FOR THE HIGHEST ELEVATIONS OF THE WETS/SANGRES...IF CURRENT PROGS PAN OUT AS EXPECTED. RATON PASS WILL BE PARTICULARLY PROBLEMATIC TONIGHT AND TUE AS STRONG N WINDS COMBINE WITH SN TO PRODUCE WHITE OUT CONDITIONS AT TIMES. CONSIDERED UPGRADING TO A BLIZZARD WARNING FOR THE RATON...BUT CURRENTLY DOES NOT LOOK LIKE WINDS WILL BE SUSTAINED LONG ENOUGH...AND HEAVIEST PRECIP OCCURS AFTER THE STRONGEST WINDS. HOWEVER...WILL NEED TO WATCH THIS AREA CLOSELY. ALSO HAVE INTRODUCED A WINTER STORM WATCH FOR TELLER AND N EL PASO FOR TONIGHT AND TUE. COULD GET PRETTY NASTY OVER MONUMENT HILL BY TUE. HOPEFULLY THIS STORM WILL PUT A DENT IN THE DROUGHT. LET IT SNOW! 44 LONG TERM... (TUESDAY - SUNDAY) ..BENEFICIAL PRECIP AT THE BEGINNING OF THE PD THEN DRYING OUT AGAIN... MODELS IN THE EARLY PART OF THIS FCST PD HAVE COME INTO GOOD AGREEMENT BRINGING THE CUTOFF LOW NORTHEASTWARD ACROSS SE CO. BY 12Z TUESDAY...SNOW AND RAIN SHOULD BE ONGOING ACROSS A GOOD PART OF THE REGION...WITH THE BEST CHANCE OF PRECIP OVER THE EAST FACING SLOPES OF THE MTNS ADJ TO THE PLAINS...AND THE RATON MESA AND PALMER DVD REGIONS. THE RAIN/SNOW LINE AT 12Z WILL LIKELY BE AROUND 5000 FEET. FOR THE MORNING RUSH HOUR...SNOW WILL LIKELY NOT ACCUMULATE MUCH ON ROAD SURFACES BETWEEN 5000 AND 6500 FEET...BUT ANYTHING ABOVE 6500 FEET WILL LIKELY BECOME SLUSHY. GRASSY SFCS BETWEEN THE AFOREMENTIONED ELEVATIONS WILL LIKELY ACCUMULATE SOME SNOW...SO THE PUEBLO AREA MAY SEE AN INCH OF MEASURABLE SNOW. OVERALL...TWO TO THREE INCHES OF SNOW WILL LIKELY OCCUR ACROSS THE EASTERN MTNS/RATON MESA AND PALMER DVD...WITH LOCALLY HEAVY ACCUMS ACROSS PIKES PEAK AND THE HIGHER ELEVATIONS OF THE EAST SLOPES OF THE WETS/SANGRES. BY MIDDAY TUESDAY...THE LOW CENTER ALOFT WILL LIKELY BE IN THE SE CO AREA AND 700 MB FLOW WILL BECOME MORE NORTHERLY ACROSS THE WETS/SANGRES. THIS SHOULD ALLOW THE SNOW TO DECREASE ACROSS THESE REGIONS AS THE FLOW WILL NOT BE AS FAVORABLE...BUT FARTHER NORTH ACROSS THE GREATER PIKES PEAK REGION MODEST NE 700 MB FLOW WILL BE ONGOING. LIKEWISE...THE PALMER DVD REGION AND RAMPARTS/PIKES PEAK WILL LIKELY SEE SNOW CONTINUING. THE RAIN/SNOW LINE SHOULD INCREASE A BIT DURING THE DAY...BUT NOT BY MUCH. BY LATE IN THE DAY TUESDAY THE RAIN/SNOW SHOULD PRETTY MUCH BE OVER ACROSS THE PLAINS...HOWEVER BOTH NAM/GFS SHOW WRAP AROUND PRECIP CONTINUING OVER THE HIGHER TRRN OF THE MTNS..ESPECIALLY THE SANGRES AND SAN JUANS. FOR THIS REASON I HAVE INCREASED POPS OVER THESE REGIONS DURING THIS TIME. NOTE THAT THE WINTER STORM WARNING FOR THE SANGRES EXPIRES AT 00Z WED. IF THE MODELS ARE CORRECT...THIS WARNING MAY NEED TO BE EXTENDED FOR THIS MTN RANGE BY ABOUT 6 HOURS OR SO. AS FOR HIGH TEMPERATURES ON TUESDAY...I HAVE DECREASED THEM...WITH TEMPS REACHING ABOUT 40F ALONG THE I-25 CORRIDOR REGION...AND THESE VALUES MAY BE A BIT TOO HIGH IF THE MODEL SOUNDINGS ARE CORRECT. OVER THE FAR E PLAINS AND SAN LUIS VALLEY...HIGHS SHOULD BE ABOUT 50F. AS FOR THE REST OF THE FCST...WE WILL BE RETURNING TO A DRY PATTERN AGAIN AS SW FLOW GRADUALLY RAMPS UP ONCE AGAIN. IF WE DO GET AS MUCH PRECIP AS THE MODELS ARE INDICATING...THEN FIRE WX CONCERNS SHOULD DROP SIGNIFICANTLY ACROSS THE FCST AREA. ATTM...THE WARMEST TEMPS SHOULD BE DURING THE FRI-SAT TIME FRAME WITH A DRY PAC FRONT COMING ACROSS THE REGION SAT NITE. TEMPS WILL COOL AGAIN ON SUNDAY. THE NEXT CHANCE OF PRECIP...ACCORDING TO THE GFS WILL BE MONDAY...BUT THE EC SIMULATION IS DRY FROM WED THROUGH NEXT WEEK. /34 AVIATION... STRONG N WINDS BEHIND A COLD FRONT WILL CONTINUE TO AFFECT KCOS AND KPUB THROUGH THE NEXT 6-12 H. SUSTAINED WINDS FORM 30-40 KTS WITH HIGHER GUSTS WILL BE POSSIBLE. WINDS WILL GRADUALLY DIMINISH THIS EVE...HOWEVER...PRECIP IS EXPECTED TO BECOME MORE LIKELY OVERNIGHT...WITH A GOOD CHANE OF SN AT KCOS AND A RAIN-SNOW MIX POSSIBLE AT KPUB LATER TONIGHT. ALONG WITH GUSTY WINDS VIS IS EXPECTED TO BE LOW OVERNIGHT IN PARTICULAR. KALS WILL ALSO SEE GUSTY NE WINDS AND THE CHANCE OF SOME SHSN...BUT THE WORST CONDITIONS WILL BE ALONG AND W OF I-25. 44 && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 6 PM MDT THIS EVENING FOR COZ084>086-089- 093. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT TUESDAY FOR COZ078-087-088. WINTER STORM WARNING UNTIL 6 PM MDT TUESDAY FOR COZ072>075-079- 080. HIGH WIND WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ069>071. WINTER STORM WATCH FROM 9 PM MDT THIS EVENING THROUGH TUESDAY AFTERNOON FOR COZ081-082-084. && $$ 31/23
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1005 AM EDT MON APR 2 2012 .SYNOPSIS... CANADIAN HIGH PRESSURE IS BUILDING INTO THE REGION TODAY INTO TUESDAY AS DEEPENING LOW PRESSURE OVER THE ATLANTIC MOVES EAST. WEAK LOW PRESSURE MOVING ACROSS SOUTHEAST CANADA TUESDAY NIGHT WILL DRAG A TRAILING COLD FRONT ACROSS WEDNESDAY MORNING. CANADIAN HIGH WILL THEN BUILD BACK IN THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ABUNDANT LOW LEVEL MOISTURE COMBINED WITH SFC HEATING IS ALLOWING STRATOCUMULUS FIELD TO EXPAND AS IT MOVES SOUTH OUT OF SOUTHERN NEW ENGLAND AND THE HUDSON VALLEY. SOME SPRINKLES WITH THE BAND OVER NEW HAVEN THAT WILL MOVE SOUTH OVER CENTRAL LONG ISLAND BETWEEN 10 AM AND NOON. LATEST RUC AND 06Z NAM SUGGESTING THAT THIS MOISTURE MIXES OUT AND SKIES CLEAR THIS AFTERNOON AS PER PREVIOUS FCST. WIND...CURRENTLY GUSTING TO AROUND 25 MPH...INCREASE THIS AFTN WITH ADDITIONAL MIXING TO 850 HPA. EXPECT FREQUENT GUSTS IN THE 25 TO 35 MPH RANGE AT WE MIX DOWN APPROX 80% OF THE 850 WIND. TEMPS ON TRACK FOR LOWER 50S INTERIOR TO MID 50S CITY/COAST. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... DEEP TROUGH AXIS GRADUALLY SLIDES EAST TONIGHT...WITH INTENSE SURFACE LOW PUSHING OUT TO SEA. RIDGING SURFACE/ALOFT BUILDS IN ON TUESDAY. TIGHT GRADIENT AND GUSTY WINDS CONTINUE OVER THE REGION TONIGHT...WITH SECONDARY SHOT OF CAA IN WAKE OF BACKSIDE SHORTWAVE. TEMPS EXPECTED TO HOLD NEAR SEASONABLE WITH MIXED LOW-LEVELS DESPITE CAA AND CLEAR SKIES. TEMPS ARE EXPECTED TO FALL INTO THE UPPER 20S ACROSS INTERIOR ZONES LATE TONIGHT. FOR COASTAL AREAS...TEMPS EXPECTED TO DROP INTO THE LOWER TO MID 30S CITY/COAST. THE COLDEST SURGE OF AIR SHOULD BE ACROSS EASTERN SECTIONS...WITH SE COASTAL CT HAVING THE BEST CHANCE OF SUB-FREEZING AIR DRAINING TO THE COAST DOWN THE CT RIVER VALLEY. AS OF 1 APRIL...WE ARE ISSUING FROST/FREEZE WATCHES/WARNINGS/ADVISORIES FOR COASTAL SECTIONS. A FREEZE WATCH FOR SE COASTAL CT IN CURRENTLY IN PLACE. GUSTY NW WINDS TO START THE DAY ON TUESDAY...GRADUALLY RELAXING THROUGH THE AFTERNOON. OTHERWISE MOSTLY SUNNY SKIES...EXCEPT FOR SOME LATE DAY CIRRUS AHEAD OF A NORTHERN STREAM SHORTWAVE. WITH MODERATING TEMPS ALOFT AND GOOD MIXING...HIGH EXPECTED TO REBOUND TO ABOVE NORMAL LEVELS...GENERALLY UPPER 50S INTERIOR TO LOWER 60S CITY/COAST. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... UPPER VORTEX WILL MEANDER ABOUT THE EASTERN CANADIAN PROVINCES/MARITIMES THROUGH THE MIDDLE OF THE WEEK...BEFORE A CUTOFF LOW APPROACHING FROM CENTRAL CANADA REINFORCES IT THU AND FRI. MEANWHILE...A SPLIT FLOW DEVELOPS ACROSS NOAM EARLY IN THE WEEK WITH A CUTOFF LOW DEVELOPING OVER THE SW AND AN AMPLIFIED RIDGE DOWNSTREAM. MOST OF THE DYNAMICS ASSOCIATED WITH THE CUTOFF LOW MOVING ACROSS SE CANADA AND NEW ENGLAND TUE NIGHT/WED WILL REMAIN TO OUR N. HOWEVER...ECMWF AND 21Z SREF MEAN BOTH CONTINUES TO PRODUCE SOME LIGHT QPF ASSOCIATED WITH THE COLD FROPA LATE TUE NIGHT/EARLY WED MORNING AND THERE COULD BE ENOUGH MOISTURE/LIFT FOR A FEW SHOWERS...SO HAVE CONTINUED WITH SLIGHT CHANCE POP. DEEP NW FLOW WILL THEN PREVAILS THROUGH FRI AS THE VORTEX OVER THE CANADIAN MARITIMES SLOWLY DEPARTS AND RIDGING BUILDS IN FROM CANADA. IT NOW APPEARS THAT THE NORTHERN BRANCH OF THE POLAR JET WILL BE DOMINANT INTO LATE WEEK...SO HAVE HIGHER CONFIDENCE THAT HIGH PRESSURE WITH DRY WEATHER SHOULD CONTINUE THROUGH THE WEEKEND...WITH A GRADUAL WARMING TREND. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... LOW PRESSURE DEEPENING EAST OF THE DELMARVA COAST WILL CONTINUE TO TRACK OUT TO SEA TODAY. MAINLY VFR TODAY. THERE ARE SOME MVFR CIGS NORTH OF THE REGION DROPPING SOUTH...WHICH COULD PRODUCE A BRIEF PERIOD OF MVFR CIGS. ONCE THESE MVFR CIGS DROP SOUTH OF THE REGION...WE SHOULD REMAIN VFR THROUGH THE DAY. WINDS WILL CONTINUE TO RAMP UP THIS MORNING AS THE LOW INTENSIFIES. NORTHWEST WINDS TODAY 20-30KT WITH SOME GUSTS TO AROUND 35KT. WINDS DIMINISH SLIGHTLY AFT 23-00Z...THEN GUSTS END ROUGHLY IN THE 5-6Z PERIOD. IN THE EXTENDED TAFS...GUSTS KICK IN AGAIN AFT 12Z TUE. ALL WIND DIRECTIONS N OF 310 TRUE TODAY. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: BRIEF PERIOD OF MVFR CIGS THIS MORNING. WINDS INCREASE THIS MORNING WITH STRONGEST WINDS AFTER 16Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: BRIEF PERIOD OF MVFR CIGS THIS MORNING. WINDS INCREASE THIS MORNING WITH STRONGEST WINDS AFTER 16Z. KLGA FCSTER COMMENTS: BRIEF PERIOD OF MVFR CIGS THIS MORNING. WINDS INCREASE THIS MORNING WITH STRONGEST WINDS AFTER 16Z. KTEB FCSTER COMMENTS: BRIEF PERIOD OF MVFR CIGS THIS MORNING. WINDS INCREASE THIS MORNING WITH STRONGEST WINDS AFTER 16Z. KHPN FCSTER COMMENTS: BRIEF PERIOD OF MVFR CIGS THIS MORNING. WINDS INCREASE THIS MORNING WITH STRONGEST WINDS AFTER 16Z. KISP FCSTER COMMENTS: BRIEF PERIOD OF MVFR CIGS THIS MORNING. WINDS INCREASE THIS MORNING WITH STRONGEST WINDS AFTER 16Z. OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... .TUESDAY...VFR. NW GUSTS TO 25 KT POSSIBLE. .WEDNESDAY...CHANCE OF CIGS BELOW 3FT EARLY...THEN VFR. .THURSDAY...VFR. .FRIDAY...VFR. && .MARINE... A TIGHT PRESSURE GRADIENT IN THE WAKE OF RAPIDLY DEEPENING LOW PRESSURE WILL INCREASE GUSTS TO AROUND GALE FORCE THIS MORNING. A GALE WARNING REMAINS IN EFFECT FOR ALL THE FORECAST WATERS THROUGH THIS AFTERNOON. WINDS ALOFT APPEAR TO SUPPORT JUST MARGINAL GALES...BUT DEEP MIXING SHOULD KEEP THE NEARSHORE THREAT THROUGH THIS AFTERNOON. GUSTS EXPECTED TO FALL BELOW GALE LATE THIS AFTERNOON...BUT SCA GUSTS STILL EXPECTED OVER ALL WATERS INTO LATE TONIGHT WITH STILL TIGHT GRADIENT AND A SECONDARY SHOT OF CAA. WINDS EXPECTED TO DIMINISH TO MARGINAL NEARSHORE SCA GUSTS TUESDAY MORNING...CONTINUING THROUGH THE AFTERNOON. OCEAN SEAS FALLING BELOW SCA TUESDAY MORNING. QUIET TUE NIGHT INTO WED MORNING AS A COLD FRONT APPROACHES AND THEN MOVES THROUGH. SCA CONDITIONS ARE LIKELY ON ALL WATERS AFTER FROPA WED AFTERNOON AND ON THE OCEAN WED NIGHT...WITH A CHANCE THAT NEAR SHORE GUSTS COULD REACH MINIMAL GALE FORCE WED AFTERNOON IN THE HARBOR AND THE OCEAN/SOUND WATERS SURROUNDING NYC AND WESTERN LONG ISLAND. QUIET THEREAFTER AS HIGH PRESSURE BUILDS FROM THE N. && .FIRE WEATHER... GENERALLY 1/4 TO 1/2 INCH OF RAIN AREA-WIDE OVER THIS WEEKEND WILL ALLOW FOR INITIALLY MOIST FINE FUELS. AN ENHANCED THREAT OF BRUSH FIRE GROWTH/SPREAD IS POSSIBLE THIS AFTERNOON WITH SEASONABLY MILD TEMPS...HUMIDITY LEVELS LOWERING INTO THE 20 PERCENT RANGE ALONG WITH STRONG NORTHERLY WINDS HELPING TO DRY THE FUELS. WILL HOLD OFF ON AN SPS...ALLOWING DAYSHIFT TO COORDINATE ON FUEL CONDITIONS WITH OUR FIRE OFFICIALS. ONCE FINE FUELS DRY OUT...ENHANCED THREAT OF BRUSH FIRE GROWTH/SPREAD IS EXPECTED TUESDAY LATE MORNING/AFTERNOON WITH MILD TEMPS...RH VALUES FALLING INTO THE LOWER 20S AND WINDS GUSTS AROUND 25 MPH. A COLD FRONTAL PASSAGE WILL PRODUCE SOME LIGHT PRECIP LATE TUE NIGHT INTO EARLY WED MORNING...BUT THEN WX CONDITIONS SHOULD BECOME CONDUCIVE TO FIRE GROWTH/SPREAD WED AFTERNOON...WITH NW WINDS GUSTING TO 30-35 MPH AND RH LOWERING TO 25-30 PERCENT. && .HYDROLOGY... NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE REMAINDER OF THE WEEK. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FREEZE WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR CTZ010>012. NY...NONE. NJ...NONE. MARINE...GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR ANZ330-335-338- 340-345-350-353-355. && $$ SYNOPSIS...GOODMAN/NV NEAR TERM...JST SHORT TERM...NV LONG TERM...GOODMAN AVIATION...BC MARINE...GOODMAN/NV FIRE WEATHER... HYDROLOGY...GOODMAN/NV
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1012 PM EDT TUE APR 3 2012 .SYNOPSIS... A WARM FRONT WILL LIFT NORTH OF THE AREA LATE TONIGHT. A BACKDOOR COLD FRONT WILL APPROACH FROM THE NORTH WEDNESDAY NIGHT. A WAVE OF LOW PRESSURE DEVELOPING ALONG THIS FRONT WILL CAUSE IT TO STALL ACROSS NORTHERN PORTIONS OF THE FORECAST AREA THURSDAY...BEFORE THE SYSTEM TRACKS OFFSHORE AND PULLS THE FRONT THROUGH THE REGION FRIDAY. COOLER HIGH PRESSURE WILL THEN RETURN FOR THE WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... LATE TUESDAY EVENING...THUNDERSTORMS CONTINUED TO FIRE ON MESOSCALE BOUNDARIES ACROSS THE SOUTHEAST AND WERE CLOSING IN ON THE FORECAST AREA FROM THE SOUTH...WEST AND NORTHWEST. A PERSISTENT THUNDERSTORM COMPLEX WILL PUSH THROUGH SOUTHERN COUNTIES/ALONG THE ALTAMAHA RIVER DURING THE NEXT COUPLE OF HOURS...JUSTIFYING A PERIOD OF LIKELY/CATEGORICAL POPS THERE. SCATTERED THUNDERSTORMS WILL ALSO DEVELOP ALONG MESOSCALE BOUNDARIES INTO WESTERN/INLAND COUNTIES. ALSO OF INTEREST...AN EXPANDING THUNDERSTORM COMPLEX WAS PROMPTING WARNINGS ACROSS SC MIDLANDS. IF THIS COMPLEX HOLDS TOGETHER...THUNDERSTORMS COULD IMPACT NORTHERN COUNTIES OF THE FORECAST AREA AFTER MIDNIGHT. GIVEN HAIL/DOWNDRAFT CAPES DEPICTED BY THE LATE EVENING SPC MESOANALYSIS...CANNOT RULE OUT AN ISOLATED SEVERE THUNDERSTORM WITH DAMAGING MICROBURSTS AND LARGE HAIL TONIGHT. HOWEVER...THE THREAT FOR SEVERE WEATHER REMAINS LOW AND SHOULD CONTINUE TO DIMINISH OVERNIGHT. LATE EVENING INSTABILITY AND SUPPORT FROM COMPLEX/MESOSCALE BOUNDARIES SUGGEST THAT THUNDERSTORMS WILL PERSIST WELL INTO THE OVERNIGHT. HOWEVER...THE 00Z NAM AND THE 01Z RUC13 SUGGEST THAT DIURNAL STABILIZATION WILL TRANSLATE TO DISSIPATING CONVECTION OVERNIGHT. THUS...CONTINUED TO TREND POPS DOWN TO SLIGHT CHANCE WELL AFTER MIDNIGHT...BUT CONFIDENCE IN POPS DIMINISHES OVERNIGHT...AND ADDITIONAL ADJUSTMENTS COULD BE REQUIRED. MEANWHILE...GIVEN LOW LEVEL MOISTURE AND RELATIVELY LIGHT WINDS... ADDED A MENTION OF PATCHY FOG ALL AREAS OVERNIGHT. FOG COULD BECOME LOCALLY DENSE IN AREAS THAT RECEIVED OR WILL RECEIVE RAIN. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... WEDNESDAY...AN UPPER LEVEL SHORTWAVE WILL STEADILY TRACK DUE EAST ACROSS THE GULF COAST STATES AND NORTHERN FLORIDA THROUGH WEDNESDAY AFTERNOON. AT THE SURFACE...A TROUGH WITH AN EMBEDDED COLD FRONT WILL TAKE SHAPE ACROSS VIRGINIA/NORTH CAROLINA BY LATE IN THE DAY. SOUTH OF THIS FRONT ACROSS THE FORECAST AREA...DEEP OFFSHORE FLOW SUGGESTS THE SEABREEZE WILL BE PINNED TO THE COAST...WITH AREAS AWAY FROM THE SHORE WARMING WELL INTO THE LOW TO MID 80S. THERE IS GENERAL CONSENSUS AMONG THE 12Z GFS AND NAM SOLUTIONS THAT SCATTERED SHOWERS/THUNDERSTORMS WILL DEVELOP DURING THE AFTERNOON...CONSIDERING DECENT INSTABILITY AND DEWPOINTS IN THE LOWER 60S DURING THE PEAK HEATING HOURS. MODEL SOUNDINGS FOR WEDNESDAY AFTERNOON ARE INDICATIVE OF A DEEPLY MIXED BOUNDARY LAYER AND INVERTED V SHAPE...WHILE WEAK UPPER LEVEL ENERGY IS PROGRESSING OVER THE FORECAST AREA BEHIND THE SHORTWAVE TROUGH ALOFT. ALTHOUGH THE BEST POTENTIAL FOR SEVERE WEATHER WILL BE FARTHER TO THE NORTH WHERE THE FRONT WILL ENHANCE FORCING...AN ISOLATED SEVERE STORM COULD BE POSSIBLE WEDNESDAY AFTERNOON/EARLY EVENING. HOWEVER...CONFIDENCE AND COVERAGE ARE TOO LOW TO WARRANT MENTION IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME. WEDNESDAY NIGHT...SCATTERED CONVECTION IS EXPECTED TO GRADUALLY DIMINISH DURING THE EVENING HOURS WITH THE LOSS OF DIURNAL HEATING AND INSTABILITY...WITH RAIN CHANCES BELOW 15 PERCENT AFTER MIDNIGHT. WARM SOUTH/SOUTHWEST FLOW AND RESIDUAL CLOUD COVER WILL SUPPORT MILD LOW TEMPERATURES IN THE LOW TO MID 60S. THURSDAY...THE SURFACE TROUGH AND BACKDOOR FRONT WILL HAVE MADE SOME PROGRESS SOUTHWARD TOWARD THE NORTH CAROLINA/SOUTH CAROLINA BORDER BY DAYBREAK THURSDAY. A CLOSED UPPER LOW TRACKING ACROSS THE GULF COAST STATES AND SOUTHERN TENNESSEE VALLEY WILL HELP DEVELOP A SURFACE LOW ALONG THE LINGERING WEST/EAST ORIENTED FRONT LATE IN THE DAY. AS THE SURFACE WAVE TAKES SHAPE JUST DOWNSTREAM OF THE UPPER LEVEL LOW...THE BACKDOOR FRONT COULD SHIFT INTO THE FAR NORTHERN SECTIONS OF THE FORECAST AREA BY THURSDAY AFTERNOON. THICK CLOUD COVER WILL KEEP TEMPERATURES A FEW DEGREES COOLER IN THE UPPER 70S TO LOW 80S. CONVECTIVE COVERAGE WILL STEADILY INCREASE THROUGH THE LATE MORNING HOURS...WITH THUNDERSTORM CHANGES BECOMING LIKELY FOR MUCH OF THE FORECAST AREA THURSDAY AFTERNOON AND EVENING. THERE REMAINS SOME CONCERN REGARDING THE POTENTIAL FOR ORGANIZED SEVERE DEVELOPMENT THURSDAY AFTERNOON. DEWPOINTS WILL ONCE AGAIN LINGER IN THE LOW 60S...WHILE LIFTED INDICES AND CAPE VALUES SUGGEST MODERATE INSTABILITY BY EARLY/MID AFTERNOON. OF SOME ADDITIONAL CONCERN IS INCREASING BULK SHEAR AND HELICITY VALUES...AS WELL AS ENHANCED FORCING ALONG THE LINGERING FRONT. STORM PREDICTION CENTER HAS PLACED THE FORECAST AREA WITHIN A 5 PERCENT RISK FOR SEVERE DEVELOPMENT ON DAY 3. WILL CONTINUE TO MONITOR MODEL TRENDS AND ALLOW LATER FORECAST SHIFTS TO DETERMINE THE NEED TO INCLUDE SEVERE MENTION IN THE HAZARDOUS WEATHER OUTLOOK FOR THURSDAY. THURSDAY NIGHT INTO FRIDAY...THE SURFACE LOW WILL DEEPEN AHEAD OF THE UPPER LEVEL TROUGH THURSDAY NIGHT...WITH BOTH FEATURES PULLING OFF THE SOUTHEAST COAST DURING THE EARLY MORNING HOURS ON FRIDAY. THIS WILL DRAG THE BACKDOOR FRONT THROUGH THE AREA...WITH DECENT SHOWER/THUNDERSTORM POTENTIAL PERSISTING THURSDAY NIGHT THROUGH FRIDAY AFTERNOON. COOL NORTHEAST FLOW BEHIND THE FRONT WILL SUPPRESS HIGH TEMPERATURES CONSIDERABLY LOWER THAN PREVIOUS DAYS...LIKELY ONLY REACHING THE UPPER 60S NORTH TO MID 70S SOUTHEAST GEORGIA. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... PRETTY DECENT MODEL AGREEMENT THIS PERIOD GIVEN THE TIME FRAME...ESPECIALLY THROUGH SUNDAY. HIGH PRESSURE WILL BUILD FROM THE NORTH FRIDAY NIGHT AS LOW PRESSURE MOVES FARTHER OFFSHORE AND AWAY FROM THE AREA. RAIN CHANCES WILL BE ENDING FROM WEST TO EAST WITH DRY CONDITIONS LIKELY BY DAYBREAK SATURDAY FOR ALL AREAS. SOME LINGERING CLOUDS ALONG WITH A CHILLY NORTH/NORTHEAST FLOW SHOULD KEEP TEMPERATURES BELOW NORMAL AROUND 70 NORTH/MID 70S SOUTH. THE COOL AIR MASS WILL THEN LINGER INTO EARLY NEXT WEEK...REINFORCED BY A DECENTLY STRONG COLD FRONT ON TUESDAY. FOR THE FIRST TIME IN A WHILE IT APPEARS TEMPERATURES WILL BE CLOSE TO NORMAL...ESPECIALLY OVER THE WEEKEND. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... AT KCHS...BRIEF PERIODS OF VFR CONDITIONS ARE POSSIBLE...BUT OVERALL PREVAILING MVFR CEILINGS THIS EVENING ARE EXPECTED TO DETERIORATE TO IFR OR LOWER CONDITIONS OVERNIGHT/EARLY WEDNESDAY. AT KSAV...ADDED A MENTION OF CBS AND SHIFTING/GUSTY WINDS 02Z-06Z TONIGHT TO ACCOUNT FOR IMPACT OF CONVECTION THAT WILL APPROACH THE TERMINAL FROM THE S/SW. EXPECT AMENDMENTS IF THUNDERSTORMS ARE EXPECTED TO DIRECTLY IMPACT THE TERMINAL. OTHERWISE...VFR THIS EVENING...THEN LOW LEVEL MOISTURE SHOULD SUPPORT AT LEAST PERIODS OF MVFR OR LOWER CONDITIONS OVERNIGHT INTO WEDNESDAY MORNING. THUNDERSTORMS WILL REDEVELOP WEDNESDAY AFTERNOON...THUS MAINTAINED A MENTION OF CBS TO BOTH TERMINALS. EXTENDED AVIATION OUTLOOK...MVFR CIGS/VSBYS POSSIBLE EARLY THURSDAY IN LOW CLOUDS/FOG...WITH INCREASED SHOWER/TSTM POTENTIAL LATER THURSDAY THROUGH FRIDAY. && .MARINE... THUNDERSTORMS AND GUSTY/SHIFTING WINDS WILL IMPACT AT LEAST GA WATERS DURING THE NEXT COUPLE OF HOURS...AND THUNDERSTORMS COULD PUSH INTO SC WATERS AFTER MIDNIGHT. OUTSIDE THUNDERSTORMS... S/SE WINDS WILL VEER T TO SW AS A WEAK WARM FRONT LIFTS NORTH OF THE REGION LATE TONIGHT. WINDS OUTSIDE THUNDERSTORMS SHOULD REMAIN 15 KT OR LESS. SEAS WILL REMAIN IN THE 2-4 FT RANGE. WEDNESDAY THROUGH SUNDAY...A BACKDOOR COLD FRONT WILL APPROACH FROM THE NORTH WEDNESDAY/WEDNESDAY NIGHT. THE FRONT WILL LIKELY REMAIN JUST NORTH OF THE WATERS UNTIL FRIDAY...WHEN LOW PRESSURE DEPARTS THE COAST AND HIGH PRESSURE BUILDS IN FROM THE NORTH. CONDITIONS SHOULD REMAIN BELOW ADVISORY LEVELS UNTIL LATE FRIDAY...WHEN NORTH/NORTHEAST WINDS SURGE BEHIND THE DEPARTING LOW SYSTEM AND BUILDING HIGH PRESSURE. AT LEAST SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE ACROSS MOST OF THE MARINE ZONES BY FRIDAY NIGHT. THERE IS A SMALL CHANCE THAT GALE FORCE GUSTS COULD OCCUR FRIDAY NIGHT INTO SATURDAY...MAINLY ACROSS THE CHARLESTON NEARSHORE WATERS AND GEORGIA WATERS BEYOND 20 NM...BUT CONFIDENCE TOO LOW TO MENTION IN THE HAZARDOUS WEATHER OUTLOOK AT THIS TIME. SEAS WILL ALSO BE INCREASING WITHIN THE FAVORABLE NORTHEAST FLOW...POSSIBLY TO NEAR 10 FT OUT TO 60 NM BY LATE FRIDAY. WINDS LOOK TO SUBSIDE SUNDAY...BUT IT WILL LIKELY TAKE A BIT LONGER FOR SEAS TO DROP BELOW ADVISORY LEVELS. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...SPR SHORT TERM...79 LONG TERM...RJB AVIATION...SPR MARINE...SPR/79
AREA FORECAST DISCUSSION...CORRECTED
NWS CHARLESTON SC
308 PM EDT MON APR 2 2012 .SYNOPSIS... A WEAK FRONT WILL DROP SOUTH INTO THE REGION TONIGHT AND LINGER THROUGH TUESDAY BEFORE LIFTING NORTH TUESDAY NIGHT. ANOTHER COLD FRONT WILL MOVE INTO THE AREA THURSDAY AND STALL INTO FRIDAY AS WEAK WAVES OF LOW PRESSURE MOVE ALONG IT. COOLER HIGH PRESSURE WILL RETURN NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... 02/19Z MESOANALYSIS AND KLTX/KRAX REFLECTIVITY DATA SHOWED THE BACKDOOR COLD FRONT EXTENDING FROM ROUGHLY CAPE FEAR ARCHING BACK TO SOUTHERN PINES...LEXINGTON AND WINSTON SALEM. THE FRONT IS STEADILY DROPPING SOUTH ALONG THE NORTH CAROLINA COAST AIDED BY POST-FRONTAL ISALLOBARIC RISES OF 3-4MB/3HRS. A VERY WARM AND SOMEWHAT HUMID AIRMASS IS IN PLACE ACROSS COASTAL SOUTH CAROLINA AND GEORGIA AHEAD OF THE FRONT WITH TEMPERATURES SOARING WELL INTO THE 80S TO NEAR 90 DEGREES. CURRENT AWIPS TIMING TOOLS AND RUC DATA SUPPORT THE FRONT REACHING THE CHARLESTON METRO AREA BY VERY LATE AFTERNOON AND THE SAVANNAH AREA BY MID-EVENING. THE PRIMARY CONCERNS THIS EVENING IS THE POTENTIAL FOR ISOLATED SEVERE TSTMS. THE AIRMASS ACROSS SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA IS SLOWLY DESTABILIZING DESPITE STIFF DOWNSLOPE FLOW CONDITIONS. EARLIER CAPPING NOTED ON RUC SOUNDINGS IS QUICKLY ERODING AS TEMPERATURES REACH NEAR 90 DEGREES. SBCAPE IS APPROACHING 1500 J/KG WITH LIFTED INDICES AS LOW AS -5C. VISIBLE SATELLITE IMAGERY ALREADY SHOW LINES OF CUMULUS BEGINNING TO BUILD ALONG VARIOUS MESOSCALE BOUNDARIES SUCH AS THE MATURING LAKE BREEZE CIRCULATIONS AROUND THE PERIPHERY OF LAKES MOULTRIE AND MARION AS WELL AS DIFFERENTIAL HEATING BOUNDARIES CREATED FROM EARLIER CLOUD COVER NORTH OF THE SOUTH SANTEE RIVER. THE VARIOUS HIGH RESOLUTION MODEL PACKAGES REMAIN SIMILAR IN THE DEPICTION OF ISOLATED SHOWERS/TSTMS INITIATING ALONG AND AHEAD OF THE SOUTHWARD MOVING BACKDOOR FRONT OVER THE NEXT FEW HOURS AS WEAK H7-H5 PERTURBATIONS CROSS THE REGION WHILE SLIDING DOWN THE EASTERN AXIS OF THE UPPER RIDGE. WILL MAINTAIN SLIGHT CHANCE POPS FOR ALL ZONES THROUGH THE EVENING WITH THE HIGHEST GRIDDED POPS WORKING SLOWLY NORTH-SOUTH WITH THE FRONT. LOCALIZED HIGHER POPS MAY BE NEEDED LATER THIS AFTERNOON OR EVENING ONCE CONVECTIVE TRENDS ARE ESTABLISHED. DCAPES NEAR 1200 J/KG AND WBZ HEIGHTS NEAR 10 KFT WILL SUPPORT A RISK FOR DAMAGING WINDS AND MARGINALLY SEVERE HAIL...BUT THE LACK OF DEEP LAYERED SHEAR SUGGESTS ANY SUCH ACTIVITY WILL REMAIN LOOSELY ORGANIZED AT BEST. WILL CONTINUE HIGHLIGHT ISOLATED SEVERE TSTMS IN THE HAZARDOUS WEATHER OUTLOOK. ANY RISK FOR SEVERE TSTMS SHOULD DIMINISH BY LATE EVENING AS INSTABILITY WANES AND UPPER RIDGE BUILDS EAST. CLOUD COVER WILL BE HEAVILY INFLUENCES BY THE AMOUNT OF CONVECTION THAT FIRES. ALTHOUGH THERE WILL BE PERIODS OF MOSTLY CLOUDY SKIES THIS EVENING WITH TSTMS...EXPECT PARTLY CLOUDY SKIES TO DOMINATE OVERALL. LOWS WILL RANGE FROM THE LOWER 60S NORTH TO MID 60S SOUTH. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... A RATHER CONVOLUTED PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE. THE UPPER RIDGE WILL BREAK DOWN ON TUESDAY ALLOWING NUMEROUS SHORTWAVES TO MOVE THROUGH THE SOUTHEAST UNITED STATES THROUGH THURSDAY. A STALLED FRONT DRAPED ACROSS THE AREA ON TUESDAY WILL CREATE A SUBSTANTIAL TEMPERATURE GRADIENT. INTERIOR SOUTHEAST GA WILL RISE INTO THE LOWER-MID 80S WHILE THE TRI-COUNTY REGION IN SC WILL STAY IN THE UPPER 70S. ISOLATED TO SCATTERED SHOWERS/STORMS ARE EXPECTED BUT COVERAGE SHOULD BE SOMEWHAT LIMITED BY THE MID-LEVEL CAPPING. THE FRONT WILL ERODE TUESDAY NIGHT BUT ANOTHER BACKDOOR FRONT WILL BE KNOCKING ON THE NORTHERN DOOR ON WEDNESDAY. DEEP WEST-SOUTHWEST FLOW AND SOME PRE-FRONTAL COMPRESSION WILL PUSH HIGH TEMPS WELL INTO THE 80S. ISOLATED/SCATTERED CONVECTION IS EXPECTED BUT THE WESTERLY SUBSIDENT FLOW SHOULD LIMIT COVERAGE YET AGAIN. THE FRONT WILL MOVE INTO THE AREA ON THURSDAY AND SEVERAL RIPPLES OF LOW PRESSURE WILL MOVE ALONG IT. A MORE FAVORABLE MID-LEVEL ENVIRONMENT AND LOW-LEVEL INSTABILITY WILL SUPPORT BETTER COVERAGE OF SHOWERS AND THUNDERSTORMS. THE COOLER AIRMASS COUPLED WITH EXTENSIVE CLOUD COVER WILL KEEP TEMPS CLOSER TO 80 DEGREES. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... AT LEAST ONE AREA OF LOW PRESSURE WILL MOVE THROUGH THE AREA ALONG THE LINGERING SURFACE FRONT...FINALLY PUSHING OFFSHORE FRIDAY NIGHT IN ACCORDANCE WITH THE ATTENDANT UPPER TROUGH OF LOW PRESSURE. HIGH PRESSURE WILL THEN BUILD FROM THE NORTH BRINGING A MUCH MORE SEASONAL AIR MASS TO AREA FOR THE WEEKEND WITH A SLIGHT MODERATION EARLY NEXT WEEK. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR FOR THE NEXT 24 HOURS. BACKDOOR COLD FRONT IS MOVING STEADILY SOUTH OUT OF NORTH CAROLINA AND WILL APPROACH KCHS BY LATE AFTERNOON...POSSIBLY ACCOMPANIED BY ISOLATED TSTMS. GIVEN THE LIMITED SPATIAL COVERAGE THAT IS EXPECTED...NO MENTION WILL BE INCLUDED IN THE KCHS TAF. CB/S WILL BE CONTINUED. TSTMS SHOULD BE SOUTH OF THE TERMINAL BY 00Z WITH LINGERING CLOUD COVER. FALLING DEWPOINTS IN THE WAKE OF THE FRONT WILL PREVENT FOG FROM BECOMING AN ISSUE OVERNIGHT. THE FRONT WILL APPROACH THE KSAV TERMINAL BY MID-EVENING. STILL COULD SEE ISOLATED TSTMS WITH THE FRONT...BUT GUIDANCE SUGGESTS ANY FRONTAL ACTIVITY WILL REMAIN NORTH. TRENDS WILL BE MONITORED HOWEVER...BUT NO MENTION OF TSTMS WILL BE INCLUDED GIVEN THE LIMITED SPATIAL COVERAGE. THICKER CLOUD COVER WILL LINGER AT KSAV OVERNIGHT...BUT CIGS WILL REMAIN VFR. LOOKS LIKE THERE WILL BE ENOUGH WIND TO PRECLUDE SIGNIFICANT FOG DEVELOPMENT. EXTENDED AVIATION OUTLOOK...OCCASIONAL REDUCED CIG/VSBY IN SCATTERED SHRA/TSRA TUESDAY THROUGH FRIDAY NIGHT. MVFR/IFR CIGS/VSBYS POSSIBLE DURING THE NIGHTTIME PERIODS IN LOW CEILINGS AND/OR FOG. && .MARINE... WINDS WILL TURN EAST/NORTHEAST BEHIND THE SOUTHWARD MOVING FRONT THIS EVENING. THE HIGHEST WINDS LOOK TO OCCUR ACROSS THE SOUTH CAROLINA WATERS WHERE A SURGE AS HIGH AS 15-20 KT CAN BE EXPECTED. WINDS WILL BE SLIGHTLY LESS ACROSS THE GEORGIA WATERS. SEAS WILL BUILD SLIGHTLY WITH THE FAVORABLE NORTHEAST FETCH...BUILDING TO 3-4 FT ALONG THE CHARLESTON COUNTY COASTAL WATERS WITH 2-3 FT ELSEWHERE. TUESDAY THROUGH SATURDAY...A COLD FRONT WILL STALL OVER THE WATERS TUESDAY WHILE DISSIPATING. ANOTHER COLD FRONT WILL APPROACH FROM THE NORTH WEDNESDAY/WEDNESDAY NIGHT AND PUSH INTO THE WATERS THURSDAY. THE FRONT WILL THEN STALL INTO FRIDAY WHILE AT LEAST ONE AREA OF LOW PRESSURE MOVES EAST ALONG IT...FINALLY PUSHING OFFSHORE FRIDAY NIGHT. HIGH PRESSURE WILL THEN BUILD FROM THE NORTH SATURDAY. CONDITIONS SHOULD REMAIN BELOW ADVISORY LEVELS THROUGH THE PERIOD UNTIL SATURDAY WHEN INCREASING NE WINDS PUSH SEAS TO AT LEAST 6 FT. && .CLIMATE... AS OF 3 PM...THE RECORD AT THE CHARLESTON AIRPORT HAS BEEN TIED AT 90 DEGREES. THERE IS A CHANCE FOR EVEN WARMER CONDITIONS PRIOR TO SUNSET. RECORD HIGHS FOR TODAY...APRIL 2ND... CHARLESTON AIRPORT..... 90 SET IN 2006 DOWNTOWN CHARLESTON.... 89 SET IN 1910 SAVANNAH AIRPORT....... 91 SET IN 1940 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...JRL LONG TERM...JRL AVIATION... MARINE... /JRL CLIMATE...
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
142 PM EDT MON APR 2 2012 .UPDATE... /ISSUED AT 1146 AM EDT MON APR 2 2012/ HAVE UPDATED THE FORECAST THROUGHOUT THE MORNING TO INCREASE CLOUD COVERAGE ACROSS THE SOUTHWEST PART OF THE CWA. HAVE ALSO SEEN DEVELOPMENT ACROSS NORTH GEORGIA. OTHERWISE...ONLY MINOR TWEAKS TO THE FORECAST. BOTH HRRR AND LOCAL WRF SUGGEST CONVECTION ALONG THE EASTERN EDGE OF THE CWA SO CONTINUED CURRENT POP FORECAST WHICH REFLECTS THIS. ALSO AGREE WITH OVERALL THINKING THAT SOME OF THE STORMS COULD BECOME STRONG. SPC HAS THE AREA IN A SEE TEXT WITH 5 PERCENT FOR WIND AND HAIL. 11 && .PREV DISCUSSION... SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... /ISSUED 435 AM EDT MON APR 2 2012/ RIDGE ALOFT CONTINUES OVER GEORGIA TODAY WITH PERSISTENT ABOVE AVERAGE TEMPERATURES AND DRY CONDITIONS. A FRONT MOVING SOUTHWARD THROUGH THE MID ATLANTIC STATES TODAY SHOULD MOVE INTO THE SAVANNAH RIVER VALLEY BY TONIGHT. SOME UNCERTAINTY BETWEEN THE MODELS ON HOW FAR WESTWARD THE FRONT WILL PUSH INTO THE CWA. HOWEVER...EASTERLY WINDS ARE SHOWN FOR AHN OVERNIGHT AND INTO THE EARLY MORNING OF TUESDAY. SO HAVE INCLUDED A SLIGHT CHANCE OF THUNDERSTORMS FOR THE EXTREME NORTHEAST CORNER THIS AFTERNOON...AND A SLIGHT CHANCE TONIGHT ALONG MUCH OF THE EASTERN SIDE OF THE CWA. MEANWHILE...A SHORT WAVE FROM THE NORTHWEST GULF MOVES INTO THE LOWER MISSISSIPPI VALLEY TONIGHT AND INTO THE OHIO VALLEY ON TUESDAY. THIS WILL BRING A CHANCE OF THUNDERSTORMS INTO THE REMAINDER OF THE CWA TUESDAY AND TUESDAY NIGHT. HAVE TAKEN A COMPROMISE ON THE MAV/MET TEMPERATURES. WITH THE POSSIBILITY OF A BACKDOOR FRONT AFFECTING THE EASTERN COUNTIES...HAVE TRENDED TOWARD THE COOLER TEMPERATURES TUESDAY AND TUESDAY NIGHT IN THAT AREA. 41 LONG TERM /WEDNESDAY THROUGH SUNDAY/... /ISSUED 435 AM EDT MON APR 2 2012/ EXTENDED PROGS APPEAR TO BE COMING INTO SOMEWHAT BETTER AGREEMENT WITH THE UPPER RIDGE BEGINNING TO FLATTEN OUT OVER THE SOUTHEAST U.S. WEDNESDAY/THURSDAY AS AN UPPER TROUGH/CLOSED LOW COMPLEX MOVES EAST FROM THE PLAINS. ECMWF CONTINUE TO BE A TAD SLOWER (AND FARTHER SOUTH) WITH THIS SYSTEM MOVING EASTWARD. BY 12Z FRIDAY GFS TAKES THE LOW ACROSS TENNESSEE AND INTO THE CAROLINAS BY THE END OF THE DAY...WHILE THE ECMWF SHOWS THE LOW OVER ALABAMA MOVING INTO EAST CENTRAL GEORGIA DURING THIS TIME PERIOD. BOTH SHOW THIS SYSTEM EAST OF OUR AREA BY SATURDAY WITH A HIGH PRESSURE RIDGE BEGINNING TO BUILD BACK ACROSS THE SOUTHEAST STATES. NONETHELESS WILL CONTINUE PREVIOUS FORECAST TREND WITH CHANCE TO GOOD CHANCE POPS MUCH OF THE AREA WEDNESDAY INTO FRIDAY...WITH SLIGHT CHANCE POPS FRIDAY NIGHT...ENDING ALL PRECIP BY SATURDAY. 49 CLIMATE... RECORDS FOR 04-02 MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAHN 89 1940 46 1915 63 1908 28 1924 KATL 88 1940 42 1915 63 1979 25 1881 1905 KCSG 86 1999 54 1993 67 2000 34 1992 1978 1961 KMCN 88 1940 48 1915 63 2000 32 1992 1935 RECORDS FOR 04-03 MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAHN 88 1934 47 1987 62 2007 26 1992 1974 KATL 86 1946 39 1987 65 1974 29 1992 1945 KCSG 88 1999 52 1987 70 1977 32 1962 1957 KMCN 89 1957 51 1901 69 1977 31 1993 1992 1971 && .AVIATION... 18Z UPDATE... SCT MID LEVEL CU-TCU AND WNW WINDS GUSTING TO AROUND 20KTS WILL PREVAIL THIS AFTERNOON. MODELS AGREE ON A BACKDOOR FRONT SAGGING INTO ATLANTA AREA BY 12-15Z TUE. AS A RESULT...EXPECT SCT025 TO ADVECT INTO ATL BY 12Z...THEN GO BKN040 BY 15Z WITH SOME DAYTIME HEATING AND THE FRONT IN THE AREA. WINDS SWING MORE NW BY 12Z TUE...THEN OVER NE BY 15Z TUE BEHIND THE BACKDOOR FRONT. THE FRONT RETREATS BACK NORTH BY 18Z TUE...RESULTING IN WINDS SWINGING BACK NW BY 18Z. SPEEDS DIMINISHING BY 00Z THIS EVENING TO 5-7KTS AND EXPECT MAYBE 6-8KTS ON TUE. CURRENT THINKING IS THE TSTM THREAT WILL BE MAINLY NORTH AND EAST OF ATL ON TUE...BUT WILL MENTION PROB30 19-23Z AT AHN FOR NOW. //ATL CONFIDENCE...18Z UPDATE... MEDIUM CONFIDENCE ON TIMING OF MID LEVEL CIGS AND WINDS SWINGING NE EARLY TUE MORNING. HIGH CONFIDENCE ON ALL OTHER ELEMENTS. 39 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 86 59 81 58 / 10 20 30 30 ATLANTA 84 65 84 63 / 5 10 20 30 BLAIRSVILLE 82 57 80 54 / 20 20 30 40 CARTERSVILLE 84 61 85 59 / 10 10 20 40 COLUMBUS 86 65 86 62 / 0 10 20 20 GAINESVILLE 85 61 81 60 / 10 20 30 40 MACON 87 62 86 61 / 0 10 20 20 ROME 85 58 86 60 / 10 10 20 40 PEACHTREE CITY 84 61 85 58 / 0 10 20 20 VIDALIA 85 64 84 65 / 10 10 30 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1146 AM EDT MON APR 2 2012 .UPDATE... HAVE UPDATED THE FORECAST THROUGHOUT THE MORNING TO INCREASE CLOUD COVERAGE ACROSS THE SOUTHWEST PART OF THE CWA. HAVE ALSO SEEN DEVELOPMENT ACROSS NORTH GEORGIA. OTHERWISE...ONLY MINOR TWEAKS TO THE FORECAST. BOTH HRRR AND LOCAL WRF SUGGEST CONVECTION ALONG THE EASTERN EDGE OF THE CWA SO CONTINUED CURRENT POP FORECAST WHICH REFLECTS THIS. ALSO AGREE WITH OVERALL THINKING THAT SOME OF THE STORMS COULD BECOME STRONG. SPC HAS THE AREA IN A SEE TEXT WITH 5 PERCENT FOR WIND AND HAIL. 11 && .PREV DISCUSSION... SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... /ISSUED 435 AM EDT MON APR 2 2012/ RIDGE ALOFT CONTINUES OVER GEORGIA TODAY WITH PERSISTENT ABOVE AVERAGE TEMPERATURES AND DRY CONDITIONS. A FRONT MOVING SOUTHWARD THROUGH THE MID ATLANTIC STATES TODAY SHOULD MOVE INTO THE SAVANNAH RIVER VALLEY BY TONIGHT. SOME UNCERTAINTY BETWEEN THE MODELS ON HOW FAR WESTWARD THE FRONT WILL PUSH INTO THE CWA. HOWEVER...EASTERLY WINDS ARE SHOWN FOR AHN OVERNIGHT AND INTO THE EARLY MORNING OF TUESDAY. SO HAVE INCLUDED A SLIGHT CHANCE OF THUNDERSTORMS FOR THE EXTREME NORTHEAST CORNER THIS AFTERNOON...AND A SLIGHT CHANCE TONIGHT ALONG MUCH OF THE EASTERN SIDE OF THE CWA. MEANWHILE...A SHORT WAVE FROM THE NORTHWEST GULF MOVES INTO THE LOWER MISSISSIPPI VALLEY TONIGHT AND INTO THE OHIO VALLEY ON TUESDAY. THIS WILL BRING A CHANCE OF THUNDERSTORMS INTO THE REMAINDER OF THE CWA TUESDAY AND TUESDAY NIGHT. HAVE TAKEN A COMPROMISE ON THE MAV/MET TEMPERATURES. WITH THE POSSIBILITY OF A BACKDOOR FRONT AFFECTING THE EASTERN COUNTIES...HAVE TRENDED TOWARD THE COOLER TEMPERATURES TUESDAY AND TUESDAY NIGHT IN THAT AREA. 41 LONG TERM /WEDNESDAY THROUGH SUNDAY/... /ISSUED 435 AM EDT MON APR 2 2012/ EXTENDED PROGS APPEAR TO BE COMING INTO SOMEWHAT BETTER AGREEMENT WITH THE UPPER RIDGE BEGINNING TO FLATTEN OUT OVER THE SOUTHEAST U.S. WEDNESDAY/THURSDAY AS AN UPPER TROUGH/CLOSED LOW COMPLEX MOVES EAST FROM THE PLAINS. ECMWF CONTINUE TO BE A TAD SLOWER (AND FARTHER SOUTH) WITH THIS SYSTEM MOVING EASTWARD. BY 12Z FRIDAY GFS TAKES THE LOW ACROSS TENNESSEE AND INTO THE CAROLINAS BY THE END OF THE DAY...WHILE THE ECMWF SHOWS THE LOW OVER ALABAMA MOVING INTO EAST CENTRAL GEORGIA DURING THIS TIME PERIOD. BOTH SHOW THIS SYSTEM EAST OF OUR AREA BY SATURDAY WITH A HIGH PRESSURE RIDGE BEGINNING TO BUILD BACK ACROSS THE SOUTHEAST STATES. NONETHELESS WILL CONTINUE PREVIOUS FORECAST TREND WITH CHANCE TO GOOD CHANCE POPS MUCH OF THE AREA WEDNESDAY INTO FRIDAY...WITH SLIGHT CHANCE POPS FRIDAY NIGHT...ENDING ALL PRECIP BY SATURDAY. 49 CLIMATE... RECORDS FOR 04-02 MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAHN 89 1940 46 1915 63 1908 28 1924 KATL 88 1940 42 1915 63 1979 25 1881 1905 KCSG 86 1999 54 1993 67 2000 34 1992 1978 1961 KMCN 88 1940 48 1915 63 2000 32 1992 1935 RECORDS FOR 04-03 MAX TEMPERATURE MIN TEMPERATURE STATION HIGH LOW HIGH LOW ------- ---------- ---------- ---------- ---------- KAHN 88 1934 47 1987 62 2007 26 1992 1974 KATL 86 1946 39 1987 65 1974 29 1992 1945 KCSG 88 1999 52 1987 70 1977 32 1962 1957 KMCN 89 1957 51 1901 69 1977 31 1993 1992 1971 AVIATION... 12Z UPDATE... /ISSUED 740 AM EDT MON APR 2 2012/ AREA OF IFR STRATUS CONTINUES TO EXPAND NORTH AND EAST INTO AL AND GA. LOOKS LIKE CLOUDS MAY HOLD TOGETHER TO REACH ATL AROUND 13Z AND THEN GRADUALLY LIFT INTO MVFR WITH HEATING. EXPECTING VFR BY AROUND 17Z. CEILINGS MAY NOT MAKE IT INTO MCN AND AHN AS IFR BUT MAY LIFT INTO MVFR. SOUTHWEST WINDS INCREASING TO 10 TO 15KT BY 15Z WITH SOME GUSTS TO NEAR 20KT AFTER 17Z. //ATL CONFIDENCE...12Z UPDATE... MEDIUM CONFIDENCE ON STRATUS. HIGH CONFIDENCE ON AL OTHER ELEMENTS. 41 && .PRELIMINARY POINT TEMPS/POPS... ATHENS 86 59 81 58 / 10 20 30 30 ATLANTA 84 65 84 63 / 5 10 20 30 BLAIRSVILLE 82 57 80 54 / 20 20 30 40 CARTERSVILLE 84 61 85 59 / 10 10 20 40 COLUMBUS 86 65 86 62 / 0 10 20 20 GAINESVILLE 85 61 81 60 / 10 20 30 40 MACON 87 62 86 61 / 0 10 20 20 ROME 85 58 86 60 / 10 10 20 40 PEACHTREE CITY 84 61 85 58 / 0 10 20 20 VIDALIA 85 64 84 65 / 10 10 30 20 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
326 PM EDT MON APR 2 2012 .SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT CHANCES OF MORE THUNDERSTORMS LATE TONIGHT THROUGH TUESDAY EVENING AND WARMER TEMPERATURES FOR TUESDAY WILL BE THE MAIN SHORT TERM CONCERNS. FOR TONIGHT...MOSTLY CLEAR SKIES EXPECTED ACROSS MUCH OF THE AREA THIS EVENING WITH SOME INCREASING IN MID LEVEL CLOUDINESS WITH MID LEVEL FRONTAL ZONE EXTENDING FROM NORTHERN LOWER MICHIGAN INTO NORTHWEST OHIO. SOME LOWER BASED CLOUDS HAVE ALSO BEEN DEVELOPING ALONG A LINE FROM NORTHWEST ILLINOIS INTO WEST CENTRAL ILLINOIS WHICH SEEM TO CORRELATE WELL WITH RUC 900/850 HPA LAYER FRONTOGENESIS FIELDS THIS AFTERNOON. THIS AXIS WILL GRADUALLY SHIFT EASTWARD LATER THIS EVENING WITH INCREASE IN CLOUDINESS LATER THIS EVENING FROM WEST TO EAST. WATER VAPOR IMAGERY NOT DEPICTING ANY IMMEDIATE SHORT WAVES OF CONSEQUENCE FOR THE LOCAL AREA TONIGHT BUT CONSISTENT SIGNAL OVER THE PAST FEW DAYS HAS BEEN FOR DEVELOPMENT OF 30 KNOT SOUTHWESTERLY LOW LEVEL JET NOSING INTO FAR NORTH CENTRAL INDIANA/SOUTHERN LOWER MICHIGAN...PERHAPS A BIT MORE DELAYED IN THE LAST FEW MODEL CYCLES. SEE LITTLE TO DEVIATE FROM PREVIOUS FORECAST FOR TONIGHT AT THIS POINT WITH MID CHANCE POPS NORTH AND LOW CHANCE POPS SOUTH...WITH THE HIGHER TSRA POPS LINING UP BETTER WITH 850 HPA MOISTURE CONVERGENCE ACROSS SOUTHERN LOWER MICHIGAN AND FAR NORTHERN INDIANA AFTER 06Z AS STRONG LOW LEVEL THETAE ADVECTION SPREADS FROM WEST TO EAST. ELEVATED MIXED LAYER ADVECTING INTO THE AREA LATER TONIGHT DOES POSE SOME UNCERTAINTY WITH MAGNITUDE OF ELEVATED INSTABILITY. TAKING A 900 HPA BASED PARCEL FROM 12Z NAM BUFFER SOUNDINGS YIELDS BETWEEN 1000-1500 J/KG OF ELEVATED CAPE AFTER 06Z. 12Z GFS BUFFER SOUNDINGS REMAIN A BIT MORE PRONOUNCED WITH THIS ELEVATED MIXED LAYER AND MID LEVEL WARM LAYER THAT WOULD RESULT IN LESSER INSTABILITY THAN INDICATED BY THE NAM. EFFECTIVE SHEAR FOR THESE ELEVATED PARCELS SHOULD DECREASE STEADILY OVERNIGHT HOWEVER WHICH SHOULD TEND TO LIMIT POTENTIAL FOR CONVECTIVE ORGANIZATION/SEVERE THREAT. PREVIOUS FORECAST IDEA OF ISOLATED LARGE HAIL THREAT STILL SEEMS IN ORDER...BUT SHIFTED A BIT LATER AFTER 06Z BASED ON TREND OF SLIGHTLY SLOWER MODEL DEPICTION OF LOW LEVEL JET AXIS SHIFTING INTO THE AREA. LINGERING ELEVATED CONVECTION SHOULD DIMINISH EARLY TUESDAY AS LOW LEVEL JET VEERS AND MOISTURE CONVERGENCE WEAKENS. A CONVECTIVELY ENHANCED VORT MAX ACROSS EASTERN TEXAS THIS AFTERNOON SHOULD LIFT NORTHWARD INTO MID MS RVR VALLEY LATE TUESDAY AFTERNOON...BUT OVERALL CONVECTIVE THREAT APPEARS TO BE LOW FOR LATE MORNING/AFTERNOON HOURS WITH FCST SOUNDINGS SUGGEST SOME CAPPING CONCERNS. THUS...HAVE LOWERED AFTERNOON TSRA POPS AND MAINTAINED HIGHEST CHANCE ACROSS THE WEST WHERE FORCING FROM THIS VORT MAX WILL LIKELY BE MAXIMIZED. BEST CHANCE OF SHOWERS AND THUNDERSTORMS LOOKS TO BE FOR THE EVENING HOURS AS ANOTHER SOUTHERN CANADIAN UPPER LEVEL SHORT WAVE PROVIDES IMPETUS FOR SFC LOW/FRONT TO SHIFT SOUTHEAST THROUGH THE AREA. LOW LEVEL FRONTOGENESIS ALSO TO STRENGTHEN AS STRONGER NORTHERLY FLOW INTERACTS WITH THIS BOUNDARY DURING THE EARLY EVENING. SEVERE POTENTIAL APPEARS TO BE RELATIVELY LOW AT THIS TIME DUE TO CONTINUED MARGINAL TO WEAK SHEAR PROFILES. HAVE ALSO INCREASED MAX TEMPS FOR TUESDAY WITH CONFIDENCE INCREASING THAT MOST IF NOT ALL OF FORECAST AREA WILL GET INTO WARM SECTOR AGAIN BEFORE FRONTAL PASSAGE IN THE FAR NORTHWEST MID TO LATE AFTERNOON. RECORD HIGHS IN THE UPPER 70S FOR FORT WAYNE AND SOUTH BEND COULD ONCE AGAIN BE AT RISK OF BEING BROKEN. && .LONG TERM... WEDNESDAY THROUGH MONDAY MAIN FOCUS OF LONG TERM PERIOD IS COOLER TEMPERATURES AND FROST POTENTIAL WEDNESDAY NIGHT THROUGH FRIDAY NIGHT. LONG TERM PERIOD BEGINS WEDNESDAY WITH SURFACE HIGH PRESSURE CENTERED NORTHWEST OF THE REGION BUILDING SOUTHEASTWARD INTO THE LOWER GREAT LAKES...AND A FRONTAL BOUNDARY SITUATED ALONG THE OHIO RIVER VALLEY. CUTOFF UPPER LOW OVER PANHANDLE REGION WILL SLOWLY TRACK EASTWARD TOWARDS MID MISSISSIPPI VALLEY. DRY CONDITIONS ARE EXPECTED WEDNESDAY AND WEDNESDAY NIGHT. KEPT PATCHY FROST MENTION IN THE NE PORTION OF THE FA...BUT INCREASED GRADIENT OF LOW TEMPS FROM NE TO SW AS CUTOFF LOW AND AFOREMENTIONED BOUNDARY PASS JUST SOUTH OF THE FA. CUTOFF LOW WILL CONTINUE EASTWARD INTO LOWER OHIO VALLEY ON THURSDAY. 12Z GFS INDICATED PRECIP POTENTIAL ACROSS THE FAR SW PORTIONS OF THE FA AS FRONTAL BOUNDARY SLIDES EASTWARD. HOWEVER...CONFIDENCE IS LOW AS 12Z GFS RUN OPENS LOW INTO POSITIVELY TILTED WAVE QUICKER AND DIVES MORE SOUTHEASTERLY THAN PREVIOUS RUN...MORE IN LINE WITH 00Z ECMWF. THURSDAY NIGHT LOOKS TO BE THE COOLEST NIGHT IN THE EXTENDED PERIOD AS SFC RIDGE AXIS SLIDES OVERHEAD. KEPT THE AREAS OF FROST MENTION IN ROUGHLY THE SAME AREAS AS PREVIOUS FCST. WILL CONTINUE TO MONITOR THIS PD OVER THE NEXT FEW FORECASTS WITH POSSIBLE NEED FOR HEADLINES...WITH LOWS NEARING 32-33 ACROSS MUCH OF THE FA. SFC RIDGE WILL CONTINUE TO SLIDE EAST ACROSS GREAT LAKES AS UPPER RIDGE AXIS MOVES ACROSS THE REGION. FRIDAY WILL AGAIN BE COOLER WITH EASTERLY WINDS AND SLOWLY MODERATING AIRMASS. KEPT PATCHY FROST MENTION IN FCST FRI NIGHT AS RIDGE AXIS WILL BE JUST EAST OF FA AND LIGHTER WINDS. SATURDAY WILL BE CONSIDERABLY WARM WITH UPPER RIDGE OVER THE AREA AND SFC HIGH EAST...RESULTING IN SOUTHERLY WINDS AND WAA. RAISED TEMPS A FEW DEGREES FROM PREVIOUS FCST/ALLBLEND. NEXT PRECIP CHANCES RETURN SAT NIGHT/SUN AS DEEPENING SFC LOW/EJECTING WRN CONUS TROF ENERGY ACROSS NRN TIER BRINGS A COLD FRONT THROUGH THE REGION. KEPT POPS CHANCE/SLIGHT CHANCE AS BEST FORCING REMAINS NORTH AND BEST MOISTURE/INSTABILITY REMAINS SOUTH. && .AVIATION... 18Z TAFS...MAIN AVIATION FORECAST CONCERN WILL BE POTENTIAL OF THUNDERSTORMS LATE TONIGHT INTO TUESDAY. IN THE MEANTIME...QUIET AVIATION CONDITIONS IN STORE WITH EASTERLY WINDS CONTINUING TO THE NORTH OF THE SFC BOUNDARY WHICH TRACKED ACROSS THE AREA YESTERDAY. MIXING HEIGHTS NOT PARTICULARLY DEEP...BUT GUSTS TO AROUND 20 KNOTS ARE EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON. FOR TONIGHT...A LOW LEVEL JET ACROSS THE MID MS VALLEY IS EXPECTED TO SHIFT INTO THE SOUTHERN GREAT LAKES REGION RESULTING IN STRENGTHENING WARM AIR ADVECTION. THIS FORCING MAY BE ENOUGH FOR SCATTERED THUNDERSTORM DEVELOPMENT OVERNIGHT...ESPECIALLY AFTER 06Z. CONFIDENCE IS LOW IN THIS SCENARIO ESPECIALLY AT KFWA WHICH MAY END UP JUST SOUTH OF THIS LOW LEVEL JET AXIS. DID ADD VCTS MENTION AT KSBN DURING THIS TIME PERIOD WITH THE EXPECTATION OF AT LEAST SCATTERED CONVECTION IN THE AREA...BUT LOW ENOUGH CONFIDENCE AT THIS POINT TO NOT INCLUDE TS IN THE FORECAST FOR TERMINAL. LULL IN PRECIP IS POSSIBLE TUESDAY LATE MORNING INTO AFTERNOON WITH LITTLE FORCING TO FOCUS ADDITIONAL STORMS AND HAVE KEPT FORECAST DRY THROUGH END OF THE PERIOD. SFC WINDS TO VEER MORE SOUTHERLY AFTER 14Z AS SFC LOW PRESSURE TRACKS INTO EASTERN IOWA. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...MARSILI LONG TERM...NG AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
141 PM EDT MON APR 2 2012 .AVIATION... 18Z TAFS...MAIN AVIATION FORECAST CONCERN WILL BE POTENTIAL OF THUNDERSTORMS LATE TONIGHT INTO TUESDAY. IN THE MEANTIME...QUIET AVIATION CONDITIONS IN STORE WITH EASTERLY WINDS CONTINUING TO THE NORTH OF THE SFC BOUNDARY WHICH TRACKED ACROSS THE AREA YESTERDAY. MIXING HEIGHTS NOT PARTICULARLY DEEP...BUT GUSTS TO AROUND 20 KNOTS ARE EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THE AFTERNOON. FOR TONIGHT...A LOW LEVEL JET ACROSS THE MID MS VALLEY IS EXPECTED TO SHIFT INTO THE SOUTHERN GREAT LAKES REGION RESULTING IN STRENGTHENING WARM AIR ADVECTION. THIS FORCING MAY BE ENOUGH FOR SCATTERED THUNDERSTORM DEVELOPMENT OVERNIGHT...ESPECIALLY AFTER 06Z. CONFIDENCE IS LOW IN THIS SCENARIO ESPECIALLY AT KFWA WHICH MAY END UP JUST SOUTH OF THIS LOW LEVEL JET AXIS. DID ADD VCTS MENTION AT KSBN DURING THIS TIME PERIOD WITH THE EXPECTATION OF AT LEAST SCATTERED CONVECTION IN THE AREA...BUT LOW ENOUGH CONFIDENCE AT THIS POINT TO NOT INCLUDE TS IN THE FORECAST FOR TERMINAL. LULL IN PRECIP IS POSSIBLE TUESDAY LATE MORNING INTO AFTERNOON WITH LITTLE FORCING TO FOCUS ADDITIONAL STORMS AND HAVE KEPT FORECAST DRY THROUGH END OF THE PERIOD. SFC WINDS TO VEER MORE SOUTHERLY AFTER 14Z AS SFC LOW PRESSURE TRACKS INTO EASTERN IOWA. && .PREV DISCUSSION... /ISSUED 1129 AM EDT MON APR 2 2012/ UPDATE... QUIET WEATHER FOR THIS AFTERNOON WITH MAIN FOCUS CONTINUING ON TEMPERATURE TRENDS. TEMPERATURES HAVE BEEN VERY SLOW TO RISE THIS MORNING DUE IN LARGE PART TO A VERY STRONG MORNING INVERSION NOTED PER AMDAR SOUNDINGS WHICH WERE ONLY MIXED TO BETWEEN 1500-2000 FT LATE THIS MORNING. SOME SUBTLE DIFFERENCES NOTED IN MIXED LAYER DEPTHS BETWEEN NAM/RUC FOR THIS AFTERNOON WITH NAM SUGGESTING A SLIGHTLY DEEPER MIXED LAYER THAT WOULD ALLOW FOR AFTERNOON HIGHS CLOSE TO THOSE CURRENTLY FORECASTED. THESE HIGHS MAY REPRESENT A BEST CASE SCENARIO IN TERMS OF MAX HEATING POTENTIAL TODAY...ESPECIALLY IF MIXING HEIGHTS ARE A BIT MORE SHALLOW LIKE THE RUC WOULD SUGGEST. WILL HOLD OFF ON ANY ADJUSTMENTS TO MAX TEMPS AT THIS TIME AND JUST REFINE DIURNAL CURVE TO PUT MOST OF TEMPERATURE INCREASE IN THE 17Z TO 20Z PERIOD DUE TO EFFECTS FROM THE INVERSION. MORE SOLID STRATOCU DECK ACROSS NORTHWEST OHIO SHOULD CONTINUE TO ERODE THROUGH THE AFTERNOON AND NOT PLAY A MAJOR ROLE IN LIMITING AFTERNOON TEMP RISES. UPDATED FORECAST SENT EARLIER THIS MORNING MAINLY TO REFINE SKY COVER TRENDS. && PREV DISCUSSION... /ISSUED 702 AM EDT MON APR 2 2012/ AVIATION.../12Z TAFS/ PATCHY STRATO CU WITH MVFR CIGS OVER NRN INDIANA EARLY THIS MORNING... AND A LITTLE MORE WIDESPREAD UPSTREAM OVER NRN OH. EXPECT WITH DIURNAL HEATING/MIXING THESE CLOUDS WILL DIMINISH AFTER SUNRISE WITH JUST PATCHY ALTO CU OR CIRRUS THIS AFTN/EVE. WK LOW WILL MOVE TOWARD THE AREA TONIGHT WITH LLJ TRANSPORTING INCRSG MOISTURE AND RESULTANT ELEVATED INSTABILITY INTO THE AREA LATE TONIGHT PSBLY LEADING TO SCT TS...THUS ADDED CB WITH LOW VFR CIGS AT BOTH TERMINALS TOWARD THE END OF THE PERIOD. GRADIENT BETWEEN SFC RIDGE MOVG TO LWR GRTLKS AND SF LOW/WARM FRONT MOVG INTO THE MS VALLEY WILL RESULT IN FAIRLY STRONG ESE SFC WINDS AT THE TERMINALS TODAY WITH GUSTS AROUND 22KT. PREV DISCUSSION... /ISSUED 457 AM EDT MON APR 2 2012/ SHORT TERM.../TODAY-TUE NGT/ SHRTWV DROPPING SSE INTO MID ATLANTIC THIS MORNING HAS PUSHED A BACKDOOR CDFNT THROUGH OUR AREA TO THE LOWER OH VALLEY. MID LEVEL CONVERGENT FLOW WAS RESULTING IN A COUPLE OF BANDS OF SCT HIGH BASED SHOWERS BEHIND THE FRONT... ONE OVER SWRN MI AND ANOTHER OVER ERN INDIANA/SWRN OH. RIDGE ALOFT BUILDING EASTWARD THIS MORNING SHOULD DIMINISH THIS ACTIVITY OVER THE NEXT 3-6HRS SO LEFT OUT OF TODAYS FCST WITH SHOWERS FCST TO END BY 12Z IN OUR AREA. RIDGE EXTENDING SOUTH FROM HUDSON BAY TO THE GRTLKS BEHIND THIS CDFNT SHOULD PROVIDE FAIR WX TODAY. CDFNT TRANSITIONS TO A STNRY FRONT FROM SRN IL TO LOW PRESSURE CENTERED OVER NEB/KS. THIS LOW ASSOCIATED WITH CLOSING OFF UPR SYSTEM OVER AZ/NM AND SHOULD GRADUALLY WEAKEN TODAY. NRN STREAM SHRTWV MOVG EAST ACROSS MT/SASK WILL RESULT IN EASTWARD MOVEMENT OF THE WKNG SFC LOW THROUGH THE SHORT TERM PERIOD. THIS WILL RESULT IN A RATHER TIGHT SFC PRESSURE GRADIENT ACROSS OUR CWA WITH E-SE SFC WINDS OF 10-20MPH. THIS SHOULD PROVIDE DECENT MIXING AND SUSPECT MODELS ARE A LITTLE TOO SHALLOW WITH THE BOUNDARY LAYER THIS AFTN...THUS STAYED CLOSE TO PREVIOUS FCST HIGHS FOR TODAY WHICH WERE GENERALLY AT OR A BIT ABOVE LATEST MOS. AS LOW MOVES CONTS SLOWLY EAST ACROSS IA TONIGHT STNRY FRONT WILL LIFT SLOWLY NE INTO IL AS A WARM FRONT. H85 THETA-E ADVECTION NE OF THE SFC WARM FRONT SPREADING INTO OUR AREA ALONG WITH ELEVATED INSTABILITY IS EXPECTED TO RESULT IN SCT TSTMS DVLPG OVERNIGHT. GIVEN EXPECTATION OF INCRSG CLOUDS AND SOME GRADIENT WINDS TONIGHT LEANED TOWARD WARMER END OF GUIDANCE FOR LOWS WHICH ARE FCST TO RANGE FROM THE U30S NE TO THE L50S SW. WK LOW IS FCST SIMILARLY BY 00Z MODELS TO TRACK EASTWARD ACROSS OUR CWA ON TUESDAY. THIS IS SLOWER THAN INDICATED BY EARLIER NAM/GFS/SREF RUNS... ALLOWING WARMER/MORE MOIST AIRMASS TO SPREAD INTO THE AREA DURING THE DAY TUE. DESTABILIZATION IS LIKELY WITH CAPE EXPECTED TO INCREASE INTO THE 1500-2500J/KG RANGE. MOIST CONVERGENCE ALONG THE WARM/CDFNT ASSOCIATED WITH THE LOW MOVG THROUGH OUR AREA MAY PROVIDE SUFFICIENT FORCING FOR SCT TSTM DEVELOPMENT. HWVR... WARM MID LEVEL TEMPS WILL RESULT IN A CAPPING INVERSION WHICH MAY NOT BREAK UNTIL LATE AFTN OR EVE. 0-6KM SHEAR FCST TO BE WK DURING THIS PERIOD, BUT GIVEN POTENTIAL DVLPG INSTABILITY, ISOLATED SVR STORMS ARE PSBL. WITH THE SLOWING TREND OF MODELS TO MOVE LOW/CDFNT THROUGH THE AREA... 00Z RUNS SUGGESTING HIGH TEMPS COULD BE 5-10F WARMER THAN OUR PREVIOUS FCST... FOR NOW UTILIZED A BLEND OF 00Z MODEL CONSENSUS AND PREVIOUS FCST TO TREND HIGHS UP ABOUT 3F. THE MODELS SLOWER TREND ON MOVING LOW THROUGH THE AREA MAY ALSO IMPACT LOWS TUE NIGHT WITH COLDER AIR PRBLY SLOWER TO ARRIVE IN OUR AREA. AGAIN JUST TRENDED UP A FEW DEGREES ATTM. && LONG TERM... WEDNESDAY THROUGH SUNDAY...THE MAIN CHALLENGES THIS PERIOD INCLUDE THE CHANCES FOR FROST WEDNESDAY NIGHT THROUGH FRIDAY NIGHT AND THE POSSIBILITY OF THUNDER OVER THE WEEKEND. FOR THIS PACKAGE...FAVORED THE ECMWF AND CANADIAN GEM ENSEMBLES. AN UPPER LOW EMBEDDED IN A RIDGE WILL DRIFT EAST AND WILL PASS SOUTH OF THE FORECAST AREA. KEPT CONDITIONS DRY THROUGH SATURDAY. HAVE TRENDED TEMPERATURES DOWN MOST PERIODS THROUGH FRIDAY NIGHT AS A CHILLY NORTH EAST TO EAST FETCH PERSISTS OVER EASTERN CANADA INTO THE WESTERN GREAT LAKES REGION. HAVE ADJUSTED THE TIMING OF FROST IN THE GRIDS AND HAZARDOUS WEATHER OUTLOOK TO MATCH THIS SCENARIO...WITH THE BEST CHANCE FOR FROST THURSDAY NIGHT. GUT FEELING IS HIGHS FRIDAY ARE STILL TOO WARM...AND MAY NEED TO BE LOWERED 3 TO 6 MORE DEGREES. THE GFS MEX MOS HIGH OF 63F AT FT WAYNE DEFINITELY LOOKS TOO WARM. CORRESPONDINGLY...GFS MEX DIURNAL SPREADS OF 30 AND 33 RESPECTIVELY FOR FRIDAY AND SATURDAY ALSO LOOK TOO LARGE. THE CANADIAN GEM ENSEMBLES EPS GRAMS LOOK GOOD WITH A TIGHT CLUSTER OF MEMBERS WITH LOWS JUST ABOVE FREEZING THURSDAY NIGHT AND HIGHS FRIDAY AOB 53 AT FT WAYNE. OTHERWISE...KEPT A CHANCE FOR THUNDER SATURDAY NIGHT INTO SUNDAY. MOISTURE IS LIMITED AND FORCING APPEARS MARGINAL AS THE SURFACE LOW TRACKS FROM THE UPPER MIDWEST INTO SOUTHERN CANADA DURING THIS PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...JT LONG TERM...SKIPPER AVIATION...MARSILI UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1129 AM EDT MON APR 2 2012 .UPDATE... QUIET WEATHER FOR THIS AFTERNOON WITH MAIN FOCUS CONTINUING ON TEMPERATURE TRENDS. TEMPERATURES HAVE BEEN VERY SLOW TO RISE THIS MORNING DUE IN LARGE PART TO A VERY STRONG MORNING INVERSION NOTED PER AMDAR SOUNDINGS WHICH WERE ONLY MIXED TO BETWEEN 1500-2000 FT LATE THIS MORNING. SOME SUBTLE DIFFERENCES NOTED IN MIXED LAYER DEPTHS BETWEEN NAM/RUC FOR THIS AFTERNOON WITH NAM SUGGESTING A SLIGHTLY DEEPER MIXED LAYER THAT WOULD ALLOW FOR AFTERNOON HIGHS CLOSE TO THOSE CURRENTLY FORECASTED. THESE HIGHS MAY REPRESENT A BEST CASE SCENARIO IN TERMS OF MAX HEATING POTENTIAL TODAY...ESPECIALLY IF MIXING HEIGHTS ARE A BIT MORE SHALLOW LIKE THE RUC WOULD SUGGEST. WILL HOLD OFF ON ANY ADJUSTMENTS TO MAX TEMPS AT THIS TIME AND JUST REFINE DIURNAL CURVE TO PUT MOST OF TEMPERATURE INCREASE IN THE 17Z TO 20Z PERIOD DUE TO EFFECTS FROM THE INVERSION. MORE SOLID STRATOCU DECK ACROSS NORTHWEST OHIO SHOULD CONTINUE TO ERODE THROUGH THE AFTERNOON AND NOT PLAY A MAJOR ROLE IN LIMITING AFTERNOON TEMP RISES. UPDATED FORECAST SENT EARLIER THIS MORNING MAINLY TO REFINE SKY COVER TRENDS. && .PREV DISCUSSION... /ISSUED 702 AM EDT MON APR 2 2012/ AVIATION.../12Z TAFS/ PATCHY STRATO CU WITH MVFR CIGS OVER NRN INDIANA EARLY THIS MORNING... AND A LITTLE MORE WIDESPREAD UPSTREAM OVER NRN OH. EXPECT WITH DIURNAL HEATING/MIXING THESE CLOUDS WILL DIMINISH AFTER SUNRISE WITH JUST PATCHY ALTO CU OR CIRRUS THIS AFTN/EVE. WK LOW WILL MOVE TOWARD THE AREA TONIGHT WITH LLJ TRANSPORTING INCRSG MOISTURE AND RESULTANT ELEVATED INSTABILITY INTO THE AREA LATE TONIGHT PSBLY LEADING TO SCT TS...THUS ADDED CB WITH LOW VFR CIGS AT BOTH TERMINALS TOWARD THE END OF THE PERIOD. GRADIENT BETWEEN SFC RIDGE MOVG TO LWR GRTLKS AND SF LOW/WARM FRONT MOVG INTO THE MS VALLEY WILL RESULT IN FAIRLY STRONG ESE SFC WINDS AT THE TERMINALS TODAY WITH GUSTS AROUND 22KT. PREV DISCUSSION... /ISSUED 457 AM EDT MON APR 2 2012/ SHORT TERM.../TODAY-TUE NGT/ SHRTWV DROPPING SSE INTO MID ATLANTIC THIS MORNING HAS PUSHED A BACKDOOR CDFNT THROUGH OUR AREA TO THE LOWER OH VALLEY. MID LEVEL CONVERGENT FLOW WAS RESULTING IN A COUPLE OF BANDS OF SCT HIGH BASED SHOWERS BEHIND THE FRONT... ONE OVER SWRN MI AND ANOTHER OVER ERN INDIANA/SWRN OH. RIDGE ALOFT BUILDING EASTWARD THIS MORNING SHOULD DIMINISH THIS ACTIVITY OVER THE NEXT 3-6HRS SO LEFT OUT OF TODAYS FCST WITH SHOWERS FCST TO END BY 12Z IN OUR AREA. RIDGE EXTENDING SOUTH FROM HUDSON BAY TO THE GRTLKS BEHIND THIS CDFNT SHOULD PROVIDE FAIR WX TODAY. CDFNT TRANSITIONS TO A STNRY FRONT FROM SRN IL TO LOW PRESSURE CENTERED OVER NEB/KS. THIS LOW ASSOCIATED WITH CLOSING OFF UPR SYSTEM OVER AZ/NM AND SHOULD GRADUALLY WEAKEN TODAY. NRN STREAM SHRTWV MOVG EAST ACROSS MT/SASK WILL RESULT IN EASTWARD MOVEMENT OF THE WKNG SFC LOW THROUGH THE SHORT TERM PERIOD. THIS WILL RESULT IN A RATHER TIGHT SFC PRESSURE GRADIENT ACROSS OUR CWA WITH E-SE SFC WINDS OF 10-20MPH. THIS SHOULD PROVIDE DECENT MIXING AND SUSPECT MODELS ARE A LITTLE TOO SHALLOW WITH THE BOUNDARY LAYER THIS AFTN...THUS STAYED CLOSE TO PREVIOUS FCST HIGHS FOR TODAY WHICH WERE GENERALLY AT OR A BIT ABOVE LATEST MOS. AS LOW MOVES CONTS SLOWLY EAST ACROSS IA TONIGHT STNRY FRONT WILL LIFT SLOWLY NE INTO IL AS A WARM FRONT. H85 THETA-E ADVECTION NE OF THE SFC WARM FRONT SPREADING INTO OUR AREA ALONG WITH ELEVATED INSTABILITY IS EXPECTED TO RESULT IN SCT TSTMS DVLPG OVERNIGHT. GIVEN EXPECTATION OF INCRSG CLOUDS AND SOME GRADIENT WINDS TONIGHT LEANED TOWARD WARMER END OF GUIDANCE FOR LOWS WHICH ARE FCST TO RANGE FROM THE U30S NE TO THE L50S SW. WK LOW IS FCST SIMILARLY BY 00Z MODELS TO TRACK EASTWARD ACROSS OUR CWA ON TUESDAY. THIS IS SLOWER THAN INDICATED BY EARLIER NAM/GFS/SREF RUNS... ALLOWING WARMER/MORE MOIST AIRMASS TO SPREAD INTO THE AREA DURING THE DAY TUE. DESTABILIZATION IS LIKELY WITH CAPE EXPECTED TO INCREASE INTO THE 1500-2500J/KG RANGE. MOIST CONVERGENCE ALONG THE WARM/CDFNT ASSOCIATED WITH THE LOW MOVG THROUGH OUR AREA MAY PROVIDE SUFFICIENT FORCING FOR SCT TSTM DEVELOPMENT. HWVR... WARM MID LEVEL TEMPS WILL RESULT IN A CAPPING INVERSION WHICH MAY NOT BREAK UNTIL LATE AFTN OR EVE. 0-6KM SHEAR FCST TO BE WK DURING THIS PERIOD, BUT GIVEN POTENTIAL DVLPG INSTABILITY, ISOLATED SVR STORMS ARE PSBL. WITH THE SLOWING TREND OF MODELS TO MOVE LOW/CDFNT THROUGH THE AREA... 00Z RUNS SUGGESTING HIGH TEMPS COULD BE 5-10F WARMER THAN OUR PREVIOUS FCST... FOR NOW UTILIZED A BLEND OF 00Z MODEL CONSENSUS AND PREVIOUS FCST TO TREND HIGHS UP ABOUT 3F. THE MODELS SLOWER TREND ON MOVING LOW THROUGH THE AREA MAY ALSO IMPACT LOWS TUE NIGHT WITH COLDER AIR PRBLY SLOWER TO ARRIVE IN OUR AREA. AGAIN JUST TRENDED UP A FEW DEGREES ATTM. LONG TERM... WEDNESDAY THROUGH SUNDAY...THE MAIN CHALLENGES THIS PERIOD INCLUDE THE CHANCES FOR FROST WEDNESDAY NIGHT THROUGH FRIDAY NIGHT AND THE POSSIBILITY OF THUNDER OVER THE WEEKEND. FOR THIS PACKAGE...FAVORED THE ECMWF AND CANADIAN GEM ENSEMBLES. AN UPPER LOW EMBEDDED IN A RIDGE WILL DRIFT EAST AND WILL PASS SOUTH OF THE FORECAST AREA. KEPT CONDITIONS DRY THROUGH SATURDAY. HAVE TRENDED TEMPERATURES DOWN MOST PERIODS THROUGH FRIDAY NIGHT AS A CHILLY NORTH EAST TO EAST FETCH PERSISTS OVER EASTERN CANADA INTO THE WESTERN GREAT LAKES REGION. HAVE ADJUSTED THE TIMING OF FROST IN THE GRIDS AND HAZARDOUS WEATHER OUTLOOK TO MATCH THIS SCENARIO...WITH THE BEST CHANCE FOR FROST THURSDAY NIGHT. GUT FEELING IS HIGHS FRIDAY ARE STILL TOO WARM...AND MAY NEED TO BE LOWERED 3 TO 6 MORE DEGREES. THE GFS MEX MOS HIGH OF 63F AT FT WAYNE DEFINITELY LOOKS TOO WARM. CORRESPONDINGLY...GFS MEX DIURNAL SPREADS OF 30 AND 33 RESPECTIVELY FOR FRIDAY AND SATURDAY ALSO LOOK TOO LARGE. THE CANADIAN GEM ENSEMBLES EPS GRAMS LOOK GOOD WITH A TIGHT CLUSTER OF MEMBERS WITH LOWS JUST ABOVE FREEZING THURSDAY NIGHT AND HIGHS FRIDAY AOB 53 AT FT WAYNE. OTHERWISE...KEPT A CHANCE FOR THUNDER SATURDAY NIGHT INTO SUNDAY. MOISTURE IS LIMITED AND FORCING APPEARS MARGINAL AS THE SURFACE LOW TRACKS FROM THE UPPER MIDWEST INTO SOUTHERN CANADA DURING THIS PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...JT LONG TERM...SKIPPER AVIATION...JT UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1120 PM MDT SUN APR 1 2012 .UPDATE... ISSUED AT 1051 PM MDT SUN APR 1 2012 ADJUSTED START TIME OF WIND ADVISORY FOR WESTERN PART OF CWA BASED ON 00Z GUIDANCE. LOOKS LIKE ADVISORY WINDS SHOULD DEVELOP OVER THESE LOCATIONS AS EARLY AS 09Z...SPREADING EASTWARD THROUGH 12Z. STRONGEST WINDS ALOFT STILL LOOK TO BE IN THE 12-18Z TIME PERIOD ACROSS THE AREA. 00Z GFS AND MAV GUIDANCE ARE THE MOST BULLISH ON DAYTIME WINDS WITH SUSTAINED WINDS WITHIN WARNING CRITERIA. LATEST NAM/SREF/RUC/HRRR ALL MUCH LESS...WITH WINDS REMAINING WITHIN ADVISORY LEVELS. WITH THIS IN MIND I DECIDED TO KEEP ADVISORY RATHER THAN UPGRADING AT THIS TIME. UPDATE ISSUED AT 846 PM MDT SUN APR 1 2012 MADE FURTHER ADJUSTMENTS TO WIND FORECAST IN THE 06-15Z PERIOD BASED ON LATEST RUC AND NAM TIMING OF FROPA. 00Z NAM STILL INDICATING HIGH END ADVISORY/NEAR WARNING CRITERIA WINDS EARLY MONDAY MORNING OVER EASTERN COLORADO. 00Z NAM AND LATEST SREF AND RUC ARE LESS BULLISH THAN EARLIER ON WARNING CRITERIA. I HAVE KEPT ADVISORY IN PLACE FOR NOW...AND WILL PROBABLY WAIT FOR 00Z GFS TO MAKE FINAL DECISION ON FURTHER ADJUSTMENTS OR POSSIBLE UPGRADES. UPDATE ISSUED AT 554 PM MDT SUN APR 1 2012 MADE MINOR CHANGES TO WIND FORECAST TO ACCOUNT FOR WINDS INCREASING QUICKER OVER WESTERN PARTS OF CWA AFTER 09Z TONIGHT AND TO BUMP UP WIND GUST WORDING. I ALSO ADDED PATCHY BLOWING DUST TO WEATHER GRIDS. IM CONCERNED WE COULD SEE WARNING CRITERIA WINDS OVER WESTERN PARTS OF THE CWA MONDAY MORNING...HOWEVER NOT A LOT OF NEW DATA TO LOOK AT AND MAKE A DECISION YET. WILL PROBABLY WAIT UNTIL 00Z DATA COMES IN TO FURTHER FINE TUNE WIND FORECAST. OTHER CHANGE WAS TO ADJUST TIMING OF PRECIP MONDAY...TO INCLUDE RAIN SHOWERS MONDAY AFTERNOON IN THE SOUTH AND WEST. 18Z NAM/GFS BOTH INDICATING AXIS OF FRONTOGENISIS MOVING NORTH AND EAST ALONG WITH DECENT MID LEVEL MOISTURE IN THE 21-00Z TIME-FRAME...SO EARLIER ARRIVAL OF RAIN CANT BE RULED OUT. RED FLAG CONDITIONS CONTINUE OVER MANY LOCATIONS ACROSS THE AREA...SO I PLAN ON LETTING THE RFW EXPIRE ON TIME AT 02Z. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 238 PM MDT SUN APR 1 2012 SOUTHWEST FLOW WILL BE OVER THE REGION TONIGHT. THE UPPER LOW WILL MOVE INTO SOUTHWEST NEW MEXICO MONDAY. A SURFACE TROUGH WILL BE OVER EASTERN COLORADO TONIGHT. A COLD FRONT WILL PUSH SOUTH ACROSS NORTHWEST KANSAS EARLY MONDAY. SUBSIDENCE WILL CONTINUE OVER THE FA TONIGHT SO POPS WILL BE NIL. SOME LIGHT PRECIPITATION WILL BE POSSIBLE MONDAY MORNING OVER WESTERN PORTIONS OF EASTERN COLORADO WHILE DYNAMICS FROM THE UPPER LOW ARE STILL REASONABLY CLOSE. BY MONDAY AFTERNOON THE LOW WILL MOVE FAR ENOUGH SOUTH SO THAT CHANCES ARE MUCH LOWER. PLAN TO CONTINUE SLIGHT CHANCE POPS IN EASTERN COLORADO MONDAY MORNING AND THEN SILENT POPS MONDAY AFTERNOON. THE REST OF THE FA WILL HAVE NIL POPS. STRONG WINDS ARE THE MAIN FOCUS OF THE FORECAST FOR MONDAY. THE GFS/NAM BOTH INDICATE GUSTS TO AROUND 50 MPH BETWEEN 12-15Z. SUSTAINED WIND WILL BE STRONG ENOUGH TO SUPPORT A WIND ADVISORY ALL DAY. SEE DETAILS ON THE WIND ADVISORY BELOW. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 238 PM MDT SUN APR 1 2012 MONDAY NIGHT WINDS WILL REMAIN GUSTY THROUGH THE NIGHT...WITH THE STRONGEST GUSTS DURING THE EVENING...AS THE COOLER TEMPERATURES ABOVE THE GROUND ALLOW THE STRONG WINDS TO MIX TO THE SURFACE. AS SUCH HAVE THE WIND ADVISORY EXTENDING INTO THE EVENING. DURING THE LATE EVENING THE WINDS WILL SLOWLY DECLINE AS THE COOLER TEMPERATURES AT THE SURFACE CAUSE MIXING TO DECLINE. THERE STILL REMAINS SOME UNCERTAINTY WITH TRACK OF THE CLOSED UPPER LEVEL LOW MONDAY NIGHT THROUGH WEDNESDAY. MODELS IN GENERAL HAVE SLOWED THE SYSTEM DOWN FROM YESTERDAY...WHICH SEEMS REASONABLE SINCE THE CLOSED LOW WILL BE OUTSIDE OF THE MAIN UPPER LEVEL FLOW. THE 12Z NAM IS FURTHER SOUTH THAN IT WAS AT THIS TIME YESTERDAY WHILE THE 12Z GFS IS FURTHER NORTH. PREFERENCE IS THE SREF AND NAM SINCE THEY ARE SLOWER AND HAVE MORE RUN TO RUN CONSISTENCY WITH THE TRACK OF THE CLOSED LOW AND ARE IN LINE WITH THE MAJORITY OF THE 6Z GEFS...BUT FAVORED MOSTLY THE SREF FOR DETERMINING AREAS OF PRECIP. SINCE THE NAM DRASTICALLY CUT BACK THE PRECIP. FOR THIS STORM SYSTEM. GENERALLY THINKING A SLOWER TREND OF THE PRECIPITATION MONDAY NIGHT THROUGH TUESDAY EVENING LOOKS TO BE THE WAY TO GO...WITH LOCATIONS SOUTH OF HIGHWAY 24 LOOKING TO HAVE THE BEST CHANCE FOR PRECIPITATION UNTIL THE STORM SYSTEM MOVES FURTHER EAST. MONDAY EVENING HAVE SLIGHT CHANCES FOR PRECIPITATION OVER EASTERN COLORADO AS THE 750-650MB SATURATES WITH ISENTROPIC LIFT OVER THAT AREA. OVERNIGHT PRECIP. CHANCES INCREASE OVER THE ENTIRE AREA FROM SOUTHWEST TO NORTHEAST AS ISENTROPIC LIFT OVERSPREADS THE AREA AND MOISTURE AHEAD OF THE CLOSED LOW BEGINS TO MOVE NORTH INTO THE AREA. SOME LOCATIONS IN EASTERN COLORADO MAY RECEIVE SOME SNOW WITH LOW TEMPERATURES AROUND FREEZING. TUESDAY PRECIP. CHANCES SLOWLY INCREASE AS THE CIRCULATION OF THE CLOSED LOW CONTINUES TO BRING MOISTURE INTO THE AREA. BIGGEST QUESTION IS HOW FAR NORTH THE MOISTURE WILL MAKE IT AS THE CLOSED LOW MOVES EAST. WITH MORE UNCERTAINTY THAT THERE WILL BE MOISTURE FOR THE ISENTROPIC LIFT TO WORK WITH AS ONE MOVES NORTH...HAVE PRECIP. CHANCES DECREASING TO THE NORTH. WINDS WILL CONTINUE TO DECREASE AS THE UPPER LEVEL WINDS DECLINE...BECOMING LIGHT BY EVENING. TUESDAY NIGHT PRECIPITATION CHANCES BEGIN TO DECREASE FROM EAST TO WEST AS THE CLOSED LOW AND WRAP AROUND MOISTURE MOVE EAST. FOR WEDNESDAY THROUGH SUNDAY THE MAIN FOCUS WILL BE THE CLOSED LOW MOVING OUT OF THE AREA AND THUNDERSTORM CHANCES TOWARD THE END OF THE WEEK. WEDNESDAY THE CLOSED CONTINUES TO MOVE OUT OF THE AREA. BOTH THE GFS AND ECMWF HAVE THE CLOSED LOW MOVING EAST OVER KANSAS...WHILE THE NAM/SREF HAVE THE CLOSED LOW MOVING EAST OVER OKLAHOMA. DESPITE THE DIFFERING POSITIONS OF THE LOW...THE MODELS AGREE THAT PRECIP. CHANCES WILL DECLINE FROM EAST TO WEST DURING THE DAY AS THE CLOSED LOW MOVES EAST. BEHIND THE CLOSED LOW A SHORT WAVE RIDGE MOVES OVER THE AREA. THURSDAY THE NEXT UPPER LEVEL TROUGH MOVES ON SHORE. BY FRIDAY MORNING THE TROUGH WILL BE OVER THE INTER MOUNTAIN WEST. AT THE SURFACE A LEE SIDE TROUGH DEVELOPS OVER EASTERN COLORADO AS THE UPPER LEVEL TROUGH APPROACHES THE TRI-STATE AREA. FRIDAY SOUTHERLY AHEAD OF AN UPPER LEVEL SHORT WAVE TROUGH BRING UP MOISTURE FROM THE SOUTH. WITH INSTABILITY TO WORK WITH CANNOT RULE OUT A FEW THUNDERSTORMS FROM FORMING OVER THE EASTERN PART OF THE AREA DURING THE AFTERNOON. FRIDAY NIGHT A COLD FRONT MOVES THROUGH THE AREA. OVER THE EAST THUNDERSTORM CHANCES CONTINUE WITH ELEVATED INSTABILITY IN PLACE AND THE LOW LEVEL JET MOVING OVER THOSE AREAS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1119 PM MDT SUN APR 1 2012 VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON...WITH MVFR CIGS POSSIBLE MONDAY EVENING. THESE LOW CIGS ARE PRIMARILY TIED TO MOISTURE ADVECTION AND PRECIP MOVING IN FROM THE SOUTH WHICH IS STILL IN QUESTION AT BOTH TERMINALS DUE TO UNCERTAINTLY REGARDING THE POSITION OF THE UPPER LOW MONDAY NIGHT. KGLD IS MOST LIKELY TO SEE RAIN SHOWERS MONDAY EVENING...HOWEVER I WAS NOT CONFIDENT ENOUGH TO ADD MORE THAN VCSH DURING THIS TAF CYCLE AND KEPT VFR IN PLACE. A COLD FRONT IS STILL ON TRACK TO PASS THROUGH THE REGION FROM THE NW TO THE SE EARLY IN THE TAF PERIOD...WITH GUSTY WINDS DEVELOPING AT BOTH TERMINALS. KGLD WILL BE FIRST TO SEE WINDS SHIFT TO THE NORTH AND INCREASE IN THE 09Z-12Z PERIOD...WITH KMCK IN THE 12Z-15Z TIME FRAME. THE STRONGEST WINDS WILL BE IN THE MORNING WITH WIND GUSTS 40-45KT. WIND GUSTS AROUND 30KT WILL CONTINUE THROUGH MONDAY EVENING AT BOTH TERMINALS. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...WIND ADVISORY FROM 3 AM TO 9 PM MDT MONDAY FOR COZ090>092. KS...WIND ADVISORY FROM 3 AM MDT /4 AM CDT/ TO 9 PM MDT /10 PM CDT/ MONDAY FOR KSZ001-013-027. WIND ADVISORY FROM 6 AM MDT /7 AM CDT/ TO 9 PM MDT /10 PM CDT/ MONDAY FOR KSZ002>004-014>016-028-029-041-042. NE...WIND ADVISORY FROM 3 AM TO 9 PM MDT MONDAY FOR NEZ079. WIND ADVISORY FROM 7 AM THIS MORNING TO 10 PM CDT THIS EVENING FOR NEZ080-081. && $$ UPDATE...DR SHORT TERM...FS LONG TERM....JTL AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1051 PM MDT SUN APR 1 2012 .UPDATE... ISSUED AT 1051 PM MDT SUN APR 1 2012 ADJUSTED START TIME OF WIND ADVISORY FOR WESTERN PART OF CWA BASED ON 00Z GUIDANCE. LOOKS LIKE ADVISORY WINDS SHOULD DEVELOP OVER THESE LOCATIONS AS EARLY AS 09Z...SPREADING EASTWARD THROUGH 12Z. STRONGEST WINDS ALOFT STILL LOOK TO BE IN THE 12-18Z TIME PERIOD ACROSS THE AREA. 00Z GFS AND MAV GUIDANCE ARE THE MOST BULLISH ON DAYTIME WINDS WITH SUSTAINED WINDS WITHIN WARNING CRITERIA. LATEST NAM/SREF/RUC/HRRR ALL MUCH LESS...WITH WINDS REMAINING WITHIN ADVISORY LEVELS. WITH THIS IN MIND I DECIDED TO KEEP ADVISORY RATHER THAN UPGRADING AT THIS TIME. UPDATE ISSUED AT 846 PM MDT SUN APR 1 2012 MADE FURTHER ADJUSTMENTS TO WIND FORECAST IN THE 06-15Z PERIOD BASED ON LATEST RUC AND NAM TIMING OF FROPA. 00Z NAM STILL INDICATING HIGH END ADVISORY/NEAR WARNING CRITERIA WINDS EARLY MONDAY MORNING OVER EASTERN COLORADO. 00Z NAM AND LATEST SREF AND RUC ARE LESS BULLISH THAN EARLIER ON WARNING CRITERIA. I HAVE KEPT ADVISORY IN PLACE FOR NOW...AND WILL PROBABLY WAIT FOR 00Z GFS TO MAKE FINAL DECISION ON FURTHER ADJUSTMENTS OR POSSIBLE UPGRADES. UPDATE ISSUED AT 554 PM MDT SUN APR 1 2012 MADE MINOR CHANGES TO WIND FORECAST TO ACCOUNT FOR WINDS INCREASING QUICKER OVER WESTERN PARTS OF CWA AFTER 09Z TONIGHT AND TO BUMP UP WIND GUST WORDING. I ALSO ADDED PATCHY BLOWING DUST TO WEATHER GRIDS. IM CONCERNED WE COULD SEE WARNING CRITERIA WINDS OVER WESTERN PARTS OF THE CWA MONDAY MORNING...HOWEVER NOT A LOT OF NEW DATA TO LOOK AT AND MAKE A DECISION YET. WILL PROBABLY WAIT UNTIL 00Z DATA COMES IN TO FURTHER FINE TUNE WIND FORECAST. OTHER CHANGE WAS TO ADJUST TIMING OF PRECIP MONDAY...TO INCLUDE RAIN SHOWERS MONDAY AFTERNOON IN THE SOUTH AND WEST. 18Z NAM/GFS BOTH INDICATING AXIS OF FRONTOGENISIS MOVING NORTH AND EAST ALONG WITH DECENT MID LEVEL MOISTURE IN THE 21-00Z TIME-FRAME...SO EARLIER ARRIVAL OF RAIN CANT BE RULED OUT. RED FLAG CONDITIONS CONTINUE OVER MANY LOCATIONS ACROSS THE AREA...SO I PLAN ON LETTING THE RFW EXPIRE ON TIME AT 02Z. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 238 PM MDT SUN APR 1 2012 SOUTHWEST FLOW WILL BE OVER THE REGION TONIGHT. THE UPPER LOW WILL MOVE INTO SOUTHWEST NEW MEXICO MONDAY. A SURFACE TROUGH WILL BE OVER EASTERN COLORADO TONIGHT. A COLD FRONT WILL PUSH SOUTH ACROSS NORTHWEST KANSAS EARLY MONDAY. SUBSIDENCE WILL CONTINUE OVER THE FA TONIGHT SO POPS WILL BE NIL. SOME LIGHT PRECIPITATION WILL BE POSSIBLE MONDAY MORNING OVER WESTERN PORTIONS OF EASTERN COLORADO WHILE DYNAMICS FROM THE UPPER LOW ARE STILL REASONABLY CLOSE. BY MONDAY AFTERNOON THE LOW WILL MOVE FAR ENOUGH SOUTH SO THAT CHANCES ARE MUCH LOWER. PLAN TO CONTINUE SLIGHT CHANCE POPS IN EASTERN COLORADO MONDAY MORNING AND THEN SILENT POPS MONDAY AFTERNOON. THE REST OF THE FA WILL HAVE NIL POPS. STRONG WINDS ARE THE MAIN FOCUS OF THE FORECAST FOR MONDAY. THE GFS/NAM BOTH INDICATE GUSTS TO AROUND 50 MPH BETWEEN 12-15Z. SUSTAINED WIND WILL BE STRONG ENOUGH TO SUPPORT A WIND ADVISORY ALL DAY. SEE DETAILS ON THE WIND ADVISORY BELOW. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 238 PM MDT SUN APR 1 2012 MONDAY NIGHT WINDS WILL REMAIN GUSTY THROUGH THE NIGHT...WITH THE STRONGEST GUSTS DURING THE EVENING...AS THE COOLER TEMPERATURES ABOVE THE GROUND ALLOW THE STRONG WINDS TO MIX TO THE SURFACE. AS SUCH HAVE THE WIND ADVISORY EXTENDING INTO THE EVENING. DURING THE LATE EVENING THE WINDS WILL SLOWLY DECLINE AS THE COOLER TEMPERATURES AT THE SURFACE CAUSE MIXING TO DECLINE. THERE STILL REMAINS SOME UNCERTAINTY WITH TRACK OF THE CLOSED UPPER LEVEL LOW MONDAY NIGHT THROUGH WEDNESDAY. MODELS IN GENERAL HAVE SLOWED THE SYSTEM DOWN FROM YESTERDAY...WHICH SEEMS REASONABLE SINCE THE CLOSED LOW WILL BE OUTSIDE OF THE MAIN UPPER LEVEL FLOW. THE 12Z NAM IS FURTHER SOUTH THAN IT WAS AT THIS TIME YESTERDAY WHILE THE 12Z GFS IS FURTHER NORTH. PREFERENCE IS THE SREF AND NAM SINCE THEY ARE SLOWER AND HAVE MORE RUN TO RUN CONSISTENCY WITH THE TRACK OF THE CLOSED LOW AND ARE IN LINE WITH THE MAJORITY OF THE 6Z GEFS...BUT FAVORED MOSTLY THE SREF FOR DETERMINING AREAS OF PRECIP. SINCE THE NAM DRASTICALLY CUT BACK THE PRECIP. FOR THIS STORM SYSTEM. GENERALLY THINKING A SLOWER TREND OF THE PRECIPITATION MONDAY NIGHT THROUGH TUESDAY EVENING LOOKS TO BE THE WAY TO GO...WITH LOCATIONS SOUTH OF HIGHWAY 24 LOOKING TO HAVE THE BEST CHANCE FOR PRECIPITATION UNTIL THE STORM SYSTEM MOVES FURTHER EAST. MONDAY EVENING HAVE SLIGHT CHANCES FOR PRECIPITATION OVER EASTERN COLORADO AS THE 750-650MB SATURATES WITH ISENTROPIC LIFT OVER THAT AREA. OVERNIGHT PRECIP. CHANCES INCREASE OVER THE ENTIRE AREA FROM SOUTHWEST TO NORTHEAST AS ISENTROPIC LIFT OVERSPREADS THE AREA AND MOISTURE AHEAD OF THE CLOSED LOW BEGINS TO MOVE NORTH INTO THE AREA. SOME LOCATIONS IN EASTERN COLORADO MAY RECEIVE SOME SNOW WITH LOW TEMPERATURES AROUND FREEZING. TUESDAY PRECIP. CHANCES SLOWLY INCREASE AS THE CIRCULATION OF THE CLOSED LOW CONTINUES TO BRING MOISTURE INTO THE AREA. BIGGEST QUESTION IS HOW FAR NORTH THE MOISTURE WILL MAKE IT AS THE CLOSED LOW MOVES EAST. WITH MORE UNCERTAINTY THAT THERE WILL BE MOISTURE FOR THE ISENTROPIC LIFT TO WORK WITH AS ONE MOVES NORTH...HAVE PRECIP. CHANCES DECREASING TO THE NORTH. WINDS WILL CONTINUE TO DECREASE AS THE UPPER LEVEL WINDS DECLINE...BECOMING LIGHT BY EVENING. TUESDAY NIGHT PRECIPITATION CHANCES BEGIN TO DECREASE FROM EAST TO WEST AS THE CLOSED LOW AND WRAP AROUND MOISTURE MOVE EAST. FOR WEDNESDAY THROUGH SUNDAY THE MAIN FOCUS WILL BE THE CLOSED LOW MOVING OUT OF THE AREA AND THUNDERSTORM CHANCES TOWARD THE END OF THE WEEK. WEDNESDAY THE CLOSED CONTINUES TO MOVE OUT OF THE AREA. BOTH THE GFS AND ECMWF HAVE THE CLOSED LOW MOVING EAST OVER KANSAS...WHILE THE NAM/SREF HAVE THE CLOSED LOW MOVING EAST OVER OKLAHOMA. DESPITE THE DIFFERING POSITIONS OF THE LOW...THE MODELS AGREE THAT PRECIP. CHANCES WILL DECLINE FROM EAST TO WEST DURING THE DAY AS THE CLOSED LOW MOVES EAST. BEHIND THE CLOSED LOW A SHORT WAVE RIDGE MOVES OVER THE AREA. THURSDAY THE NEXT UPPER LEVEL TROUGH MOVES ON SHORE. BY FRIDAY MORNING THE TROUGH WILL BE OVER THE INTER MOUNTAIN WEST. AT THE SURFACE A LEE SIDE TROUGH DEVELOPS OVER EASTERN COLORADO AS THE UPPER LEVEL TROUGH APPROACHES THE TRI-STATE AREA. FRIDAY SOUTHERLY AHEAD OF AN UPPER LEVEL SHORT WAVE TROUGH BRING UP MOISTURE FROM THE SOUTH. WITH INSTABILITY TO WORK WITH CANNOT RULE OUT A FEW THUNDERSTORMS FROM FORMING OVER THE EASTERN PART OF THE AREA DURING THE AFTERNOON. FRIDAY NIGHT A COLD FRONT MOVES THROUGH THE AREA. OVER THE EAST THUNDERSTORM CHANCES CONTINUE WITH ELEVATED INSTABILITY IN PLACE AND THE LOW LEVEL JET MOVING OVER THOSE AREAS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 531 PM MDT SUN APR 1 2012 VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE PERIOD...HOWEVER...THERE IS A CHANCE FOR MVFR CIGS VERY LATE IN THE PERIOD. HAVE HELD OFF ON MENTIONING AT THIS TIME AND WILL LET SUBSEQUENT SHIFTS ANALYZE THIS. OTHERWISE...A COLD FRONT WILL PUSH THROUGH THE AREA DURING THE MORNING HOURS. WINDS WILL SWITCH TO THE NORTH AND BECOME WINDY WITH GUSTS IN THE 40 KNOT RANGE LIKELY. && .GLD WATCHES/WARNINGS/ADVISORIES... CO...WIND ADVISORY FROM 3 AM TO 9 PM MDT MONDAY FOR COZ090>092. KS...WIND ADVISORY FROM 3 AM MDT /4 AM CDT/ TO 9 PM MDT /10 PM CDT/ MONDAY FOR KSZ001-013-027. WIND ADVISORY FROM 6 AM MDT /7 AM CDT/ TO 9 PM MDT /10 PM CDT/ MONDAY FOR KSZ002>004-014>016-028-029-041-042. NE...WIND ADVISORY FROM 3 AM TO 9 PM MDT MONDAY FOR NEZ079. WIND ADVISORY FROM 7 AM TO 10 PM CDT MONDAY FOR NEZ080-081. && $$ UPDATE...DR SHORT TERM...FS LONG TERM....JTL AVIATION...BAS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
637 PM CDT TUE APR 3 2012 .UPDATE... UPDATE ISSUED AT 528 PM CDT TUE APR 3 2012 USED THE HRRR MODEL TRENDS FOR THIS FORECAST. A FEW SHOWERS HAVE DEVELOPED ALONG THE NORTHWEST EDGE OF OUR CWA AND THAT IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF HOURS. MAJORITY OF MODELS WANT TO DEVELOP AN MCS OVER CENTRAL MISSOURI...MOVE IT EAST THEN SOUTHEAST WHICH MEANS IT MIGHT CLIP THE SOUTHWEST INDIANA AREA. SO WENT WITH HIGH CHANCE AND LIKELY POPS OVER THE NORTHERN SECTIONS TONIGHT. BLENDED A BIT DURING THE MORNING HOURS SO THAT IT IS A SMOOTHER TRANSITION ACROSS THE SOUTHERN SECTIONS. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 325 PM CDT TUE APR 3 2012 A WEAK SHORT WAVE ALOFT WILL BEGIN TO INTERACT WITH A SURFACE FRONT LIFTING NORTH OF THE REGION TONIGHT. ACTUALLY WAITING FOR CONVECTION TO START FIRING OVER THE THE WESTERN HALF OF THE REGION ANYTIME LATE THIS AFTERNOON. SURFACE HEATING AHEAD OF THIS SYSTEM...ESP EAST OF THE MS RIVER WILL HELP GENERATE SURFACE BASED LI VALUES IN THE -4 TO -8 RANGE. IF DEBRIS CLOUDS DO NOT INHIBIT THIS INSTABILITY FROM FORMING...SOME OF THE THUNDERSTORMS THAT DEVELOP COULD BE QUITE STRONG TO SEVERE IN THE LATE AFTERNOON INTO EARLY EVENING. DUE TO RELATIVELY LIGHT FLOW ALOFT...IF ANY ISOLATED STRONG CONVECTION DOES MANAGE TO DEVELOP...IT WILL LIKELY BE PULSE-TYPE CLUSTERS IN NATURE...WITH RAPID GROWTH AND DECAY OF EMBEDDED CELLS. ONCE THE SFC FRONT AND H50 TROF MOVE NORTH OF THE FORECAST AREA LATER TONIGHT...WE WILL BE UNDER THE INFLUENCE OF RICH MOIST SW FLOW AT ALL LEVELS. THOUGH NO REAL TRIGGER IS INDICATED AT THIS TIME...THIS TYPE OF PATTERN COULD PRODUCE SCATTERED SHOWERS AND STORMS AT ABOUT ANY TIME. THEREFORE...WILL LEAVE AT LEAST SCT MENTIONING IN THE FORECAST ALL OF TONIGHT FOR OFF AND ON SHOWERS/STORMS. GOOD NEWS IS THAT WE WILL LOSE MUCH OF THE DAYTIME HEATING/INSTABILITY AND MID LEVEL FORCING...SO SEVERE ASPECT WILL BE LITTLE TO NULL. LITTLE CHANGE WITH THE MODELS/ENSEMBLES FOR WED. CONTINUE TO SHOW AN INITIALLY SLOW MOVING CLOSED H5 LOW MOVING ACROSS THE CENTRAL PLAINS AND INTO W TN BY 06Z FRI AS SURFACE LOW ALSO MOVES SE ACROSS MAINLY THE SW PART OF THE PAH FORECAST AREA. ACCORDINGLY THE BEST CHANCE OF SHOWERS/TSTMS WILL GENERALLY BE WEDNESDAY AFTERNOON INTO WED NIGHT EXCEPT IN THE OZARK FOOTHILLS OF SE MO WHERE THE BEST CHANCES MAY ARRIVE AS EARLY AS WEDNESDAY MORNING. A SURFACE HIGH PUSHING S INTO THE GREAT LAKES REGION WILL BRING DRIER AIR THURSDAY NIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 325 PM CDT TUE APR 3 2012 THE LATEST MODELS AGREE THAT FRIDAY WILL BE A VERY DRY DAY WITH SOME WIND APPROACHING CRITICAL FIRE WEATHER THRESHOLDS. ALSO WITH WINDS MAINLY OUT OF THE NORTHEAST WOULD NOT EXPECT MUCH OF A REBOUND ON RH DURING THE DAY LIKE THE MODELS ARE SUGGESTING. SO WOULD EXPECT AT LEAST AN INCREASED FIRE DANGER ALTHOUGH FUELS MAY BE WET FROM PRECEDING RAINS. WILL PULL DEW POINTS DOWN FOR FRIDAY AT LEAST IN THE MIDDLE 30S FOR NOW AND MONITOR CLOSELY FOR EVEN DRIER WEATHER. FORECAST SOUNDING WOULD SUGGEST NEAR 30 AND THE NAM WOULD SUGGEST MID 20S DEW POINTS. WINDS SHOULD DECREASE SATURDAY AS SURFACE HIGH SETTLES OVER THE HEARTLAND. BOTH THE 12Z TUE GFS AND 00Z TUE ECMWF ARE IN UNUSUALLY FAIR AGREEMENT WITH A COLD FRONT TRAVERSING THE REGION SATURDAY NIGHT INTO SUNDAY MORNING. HOWEVER THE ECMWF IS MUCH DRIER WITH ONLY SPOTTY QPF...WHILE THE WETTER GFS HAS MORE SOLID COVERAGE AMOUNTS ARE MEAGER WITH LESS THAN A QUARTER INCH ANYWHERE. HOWEVER THEY BOTH AGREE THE PRECIP WILL BE POST FRONTAL SHOULD ANY OCCUR. SO WILL LEAVE IN SLGT CHC IN SUNDAY MORNING AND MIGHT HAVE TO TRIM POPS A BIT PRIOR TO SUNDAY MORNING TO BETTER REFLECT POST FRONTAL PRECIP. THERE WILL BE A REINFORCING FRONT MONDAY BRINGING YET ANOTHER SHOT AT SOME PRECIP. AFTER THAT HIGH PRESSURE RETURNS NEXT WEEK. AS FOR TEMPS WILL GO WITH ABOVE NORMAL TEMPS OR PERSISTENCE FCST UNTIL THE REINFORCING FRONT AND THEN WILL ACTUALLY HAVE A SHOT AT BELOW NORMAL TEMPS BY TUESDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 637 PM CDT TUE APR 3 2012 ISOLATED SHRA/TSTM POSSIBLE AT KCGI/KPAH MAINLY FROM 02Z-08Z...SO INCLUDED CB. VFR CONDITIONS EXPECTED AT KCGI/KPAH...WITH MVFR CIGS LIKELY AFTER 08Z AT KEVV/KOWB...IMPROVING TO VFR AFTER 15Z. SHRA/TSTM CHANCES RETURN TO KCGI/KPAH AFTER 15Z...AND AT KEVV/KOWB AFTER 18Z...WITH INCREASING CHANCES THROUGH THE AFTERNOON AT ALL SITES. WINDS WILL GENERALLY BE FROM THE SW TO W AT 5 TO 15 KTS. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...NONE. MO...NONE. IN...NONE. KY...NONE. && $$ UPDATE...PS SHORT TERM...GM LONG TERM....KH AVIATION...RST
AREA FORECAST DISCUSSION
NWS JACKSON KY
141 AM EDT MON APR 2 2012 .UPDATE... ISSUED AT 945 PM EDT SUN APR 1 2012 A NARROW LINE OF SHOWERS AND THUNDERSTORMS HAS DEVELOPED NORTH OF A LINE FROM INDIANAPOLIS TO DAYTON OVER THE PAST FEW HOURS. THIS IS MOST LIKELY TH LINE OF SHOWERS AND STORMS THAT THE HRRR HAS BEEN PICKING UP ON. THUS...THIS IS THE LINE THAT IS MOST LIKELY TO AFFECT US TONIGHT. BASED ON THE MOVEMENT AND SPEED OF THIS LINE...IT WILL NOT MAKE IT INTO THE BLUEGRASS UNTIL 3 OR 4 AM AT THE EARLIEST. WITH THE SURFACE ALREADY DECOUPLING UNDER CLEAR SKIES...WIND THREAT FROM ANY OF THESE STORMS APPEARS VERY MARGINAL AT BEST. ANY THREAT WILL LIKELY COME FROM LARGE HAIL...AND EVEN THIS IS QUESTIONABLE. THUS...SEVERE THREAT LOOKS MUCH MORE MARGINAL NOW...BUT STILL CANNOT BE RULED OUT. HAVE TRIMMED BACK POPS ACROSS THE SOUTHWEST A BIT MORE AS IT APPEARS MOST LIKELY TO AFFECT THE NORTHEASTERN TWO THIRDS OF THE FORECAST AREA. KEPT SOME POPS AROUND DURING THE MORNING ACROSS THE SOUTHEAST AS WE COULD HAVE SOME BACKBUILDING ALONG THIS LINE OF SHOWERS AND STORMS. OTHERWISE...THE ACTIVITY SHOULD COME TO AN END THERE BY MIDDAY...WITH THE AFTERNOON TURNING DRIER. UPDATE ISSUED AT 738 PM EDT SUN APR 1 2012 AFTER A CLOUDY DAY WITH SOME RAIN SHOWERS...SKIES HAVE CLEARED OUT ACROSS EASTERN KENTUCKY THIS EVENING. IN ACCORDANCE...HAVE ALTERED THE FORECAST TO REFLECT MORE CLEAR SKIES OVER THE NEXT SEVERAL HOURS. HOWEVER...SHOWERS AND A FEW STORMS ARE ALREADY BEGINNING TO DEVELOP TO THE NORTH FROM JUST NORTHWEST OF INDIANAPOLIS TO JUST NORTH OF WILMINGTON OHIO. THE HRRR SHOWS THIS ACTIVITY PUSHING SOUTH INTO OUR NORTHERN AREAS CLOSE TO MIDNIGHT. IT LOOKS INCREASINGLY LIKELY ONLY THE EASTERN COUNTIES WILL STAND THE BEST CHANCE OF RAIN TONIGHT...SO HAVE REMOVED POPS FROM OUR SOUTHWEST ZONES. OTHERWISE...MADE SOME MINOR ADJUSTMENT TO TEMPERATURES AND WINDS. UPDATE ISSUED AT 526 PM EDT SUN APR 1 2012 LAST OF THE MCS IS FINALLY DEPARTING OFF TO OUR SOUTHEAST...WITH SKIES QUICKLY CLEARING ACROSS THE AREA THIS EVENING. THIS SHOULD ALLOW FOR MOST PLACES TO REACH THEIR HIGH FOR THE DAY OVER THE NEXT HOUR OR TWO AS TEMPERATURES QUICKLY SHOOT UP WITH THE SUNSHINE. WITH STABLE AREA ENTRENCHED ACROSS EASTERN KENTUCKY STRETCHING NORTH INTO SOUTHERN OHIO...ANY DEVELOPING MCS WILL BE AT LEAST 3 TO 6 HOURS BEFORE IT IMPACTS OUR NECK OF THE WOODS. WITH THIS IN MIND...HAVE GONE AHEAD AND DELAYED THE BETTER PRECIPITATION CHANCES UNTIL AFTER 04Z (MIDNIGHT). THE HRRR SEEMS TO HAVE THE BEST TIMING AND HANDLING ON THE SITUATION WITH ALL OTHER MODELS TO AGGRESSIVE ON REDEVELOPING ACTIVITY IN THE STABLE BOUNDARY LAYER OVER THE NEXT FEW HOURS. NO INDICATION THIS WILL HAPPEN AS CLOUDS ARE FEW AND FAR BETWEEN. THUS...THE HRRR INDICATION OF LATER CONVECTION SEEMS LIKE THE WAY TO GO UNTIL SOMETHING SHOWS ME OTHERWISE. STILL GOING TO BE MAINLY A HAIL THREAT...ESPECIALLY GIVEN MOST OF THE ACTIVITY SHOULD BE ELEVATED. WILL CONTINUE TO MONITOR FOR ADDITIONAL UPDATES AS EVENTS UNFOLD OVER THE NEXT 3 TO 6 HOURS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 359 PM EDT SUN APR 1 2012 THE LEFTOVER MCS IS FINALLY MAKING AN EXIT ACROSS THE AREA...WITH THE BACK EDGE LIKELY TO EXIT BETWEEN 4 AND 5 PM. HIGHS HAVE REALLY BEEN HAMPERED BY THE CLOUD COVER...BUT DO EXPECT A LATE IN THE DAY PUSH...WITH SOME LOW TO MID 70S FOUND WEST OF I-75...WHILE MOST OTHERS RANGE FROM THE MIDDLE 60S TO AROUND 70 DEGREES. THE MODELS CONTINUE TO PLAY UP ANOTHER THUNDERSTORM COMPLEX TO DEVELOP ACROSS THE UPPER OHIO BASIN LATER THIS EVENING IN RESPONSE TO A DIGGING SHORT WAVE TROUGH WHICH WILL NOSE IN FROM THE SAINT LAWRENCE RIVER VALLEY OVERNIGHT. THE MODEL TIMING OF THIS ACTIVITY IF IT DOES HAPPEN...SEEMS A BIT FAST...AS THERE IS NOTHING POPPING YET IN NORTHERN OHIO. WILL CONTINUE TO ALLOW FOR SOME GOOD CHANCE POPS LATER TONIGHT FOR THE NORTHEAST HALF OF THE AREA...SCALING BACK QUICKLY TO SLIGHT CHANCE TO THE SOUTHWEST. AS FOR THE SEVERE THREAT...HAVE EVEN LESS CONFIDENCE IN THIS...AS WE HAVE BEEN STABILIZED BY THE STORMS THAT TOOK PLACE THIS AFTERNOON. WILL HAVE TO WAIT AND SEE HOW THE ATMOSPHERE RECOVERS TONIGHT...WITH AT LEAST LIGHT SOUTHWEST WINDS ADVECTING SOME LOW LEVEL MOISTURE...WHICH MAY RECHARGE US SOMEWHAT. THIS COMPLEX...WILL HELP DRAG A BACKDOOR COOL FRONT THROUGH THE AREA DURING THE DAY TOMORROW. BESIDES SOME LEFTOVER CONVECTION IN THE MORNING...DO NOT EXPECT ANY RE-FIRING LATER IN THE DAY...WITH THE MODEL SOUNDINGS SHOWING SOME DECENT CAPPING. THE FRONT WILL THEN MOVE BACK TO THE NORTHEAST MONDAY NIGHT AS A WARM FRONT...PERHAPS KICKING OFF SOME ISOLATED CONVECTION AS THIS OCCURS. AS FOR TEMPERATURES...ABOVE NORMAL READINGS WILL CONTINUE...ALTHOUGH READINGS HAVE COME IN A BIT COOLER FOR MONDAY WITH A LITTLE MORE COOLER AND DRIER AIR INTRUSION...SO 70S WILL MOST LIKELY BE THE RULE FOR MOST LOCATIONS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 359 PM EDT SUN APR 1 2012 A RATHER COMPLEX AND SOMEWHAT PROGRESSIVE PATTERN IS ANTICIPATED DURING THE LONG TERM PERIOD. MOST OF THE TIME THE MAIN BAND OF WESTERLIES ARE EXPECTED TO RESIDE TO OUR WEST...NORTH OR NORTHEAST WITH UPPER LEVEL RIDGING POSSIBLY DOMINATING DURING TWO DISTINCT PERIODS...WITH THE HIGHEST CHANCE OF THIS LATE IN THE PERIOD. OVERALL...MODELS ARE IN REASONABLY GOOD AGREEMENT WITH THE PATTERN WITH SOME DIFFERENCES LATER IN THE PERIOD AND SOME TIMING DIFFERENCES FROM INDIVIDUAL MODEL RUN TO MODEL RUN. EARLY ON...A WARM FRONT WILL BE MOVING NORTHEAST AND POSSIBLY EXIT NORTHEAST OF THE AREA BY TUESDAY AFTERNOON OR EVENING. MODELS GENERALLY DEVELOP PRECIP ONLY OVER THE EASTERN HALF OF THE CWA EARLY IN THE PERIOD...WITH A POSSIBLE PERIOD OF SHORTWAVE RIDGING/DRY SLOTTING OCCURRING BEFORE A COLD FRONT APPROACHES LATE IN THE DAY OR TUE NIGHT. THIS COLD FRONT WILL DROP SLOWLY SOUTH FROM TUE NIGHT INTO WED...WITH THE MODEL CONSENSUS TAKING THE BOUNDARY SOUTH OF THE CWA BY WED EVENING. HOWEVER...THE BOUNDARY SHOULD THEN STALL FOR A TIME...THOUGH THE MODELS VARY IN HOW LONG DUE TO DIFFERENCES IN HANDLING AN UPPER LOW THAT WILL MEANDER SOUTH OF A NORTHERN PLAINS/NORTHERN GREAT LAKES RIDGE FROM THE SOUTHERN ROCKIES ACROSS THE PLAINS AND MS VALLEY AND ON INTO THE EASTERN CONUS...POSSIBLY ACROSS THE TN VALLEY AND INTO THE SOUTHERN APPALACHIANS AND THEN OFF THE EASTERN SEABOARD. THIS UPPER LOW IS EXPECTED TO FOLLOW THIS MEANDERING PATH FROM THE START OF THE PERIOD ON TUE THROUGH FRI. AS MENTIONED BY THE PREVIOUS FORECASTER....BUT FRI IT SHOULD FINALLY GET PICKED UP BY A TROUGH TO ITS NORTHEAST AND THIS SHOULD THEN TAKE IT OUT TO SEA. THEREAFTER...THE MODEL CONSENSUS IS FOR THE UPPER LEVEL RIDGE TO BUILD IN AND DOMINATE THAT LAST TWO TO TWO AND A HALF DAYS OF THE PERIOD. AS FOR POPS...WENT WITH SLIGHT CHANCE TO CHANCE POPS EARLY ON TUE WITH THE WARM FRONT AND THEN INCREASED POPS LATE ON TUE INTO TUE EVENING IN ADVANCE OF THE APPROACHING COLD FRONT AND SHORTWAVE THAT THE MODEL CONSENSUS TAKES ACROSS THE OH VALLEY REGION OR THE CWA ON TUE NIGHT. THE BOUNDARY SHOULD CONTINUE SLIPPING SOUTH ON WED AND CONTINUED CHANCE POPS DURING WED...BUT GRADUALLY LOWERED POPS IN THE NORTH FARTHER AWAY FROM THE BOUNDARY. A SFC LOW MAY DEVELOP ALONG THE BOUNDARY AS THE UPPER LOW APPROACHES AROUND MIDWEEK AND SLOW THE SOUTHWARD PROGRESS OF THE FRONT AND HOLD IN CHANCES FOR ISOLATED TO SCATTERED CONVECTION AS THE SFC LOW AND UPPER SYSTEM PROBABLY TRACK JUST TO OUR SOUTH ACROSS THE TN VALLEYS. ONCE THE UPPER SYSTEM TRACKS EAST...PRECIP CHANCES WILL DIMINISH LATE THU NIGHT OR FRI. FOR NOW THE END OF THE FORECAST IS EXPECTED TO BE DRY...WITH UPPER LEVEL RIDGING DOMINATING. WITH THIS RIDGE...OPTED TO FAVOR THE ECMWF RUNS. TEMPERATURES SHOULD BE WARMEST AND MOST ABOVE NORMAL ON TUESDAY AND THEN MORE MODEST DEPARTURES OF ABOUT 5 DEGREES ABOVE NORMAL AT THE END OF THE PERIOD. OVERNIGHT LOWS SHOULD AVERAGE AT LEAST 5 DEGREES ABOVE NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1 AM EDT MON APR 2 2012 VFR CONDITIONS NOTED AT ISSUANCE WITH A LINE OF CONVECTION DROPPING SOUTH INTO NERN KY. AREAS NORTH AND EAST OF A LINE FROM KI39 THRU KJKL TO KPBX WILL HAVE THE BEST CHANCE OF SEEING PRECIP...HOWEVER CIGS ARE GENERALLY EXPECTED TO REMAIN LOW END VFR THRU THE REMAINDER OF THE OVERNIGHT. FOG WILL BE POSSIBLE AGAIN AND HAVE TRENDED A LITTLE MORE FOR LOZ AND SME. LLWS WILL ALSO BE A FACTOR OVERNIGHT WITH A -KT LOW LEVEL JET OVERHEAD AND LIGHT TO CALM SFC WINDS. SHRA WILL SLIDE OFF TO THE EAST AS FOG DISSIPATES SHORTLY AFTER SUNRISE...BUT LOW CIGS MY LINGER THRU THE MORNING AROUND M/VFR THRESHOLDS. WINDS ARE EXPECTED TO PICK UP AGAIN DURING THE MORNING WITH A NE COMPONENT AT THE SFC UP THRU ABOUT 3 KFT. && .JKL WATCHES/WARNINGS/ADVISORIES...NONE. $$ UPDATE...KAS SHORT TERM...GEOGERIAN LONG TERM....JP AVIATION...MB
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
807 PM EDT TUE APR 3 2012 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE AREA TONIGHT, BRINGING THE CHANCE OF SHOWERS AND THUNDERSTORMS. A LINGERING FRONTAL BOUNDARY BEHIND THE LOW WILL SLIDE SOUTH OF THE AREA AND END THE CHANCE OF SHOWERS BY WEDNESDAY AFTERNOON. HIGH PRESSURE WILL THEN BRING DRY AND SEASONABLE CONDITIONS INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... THE LATEST RUC MID-LEVEL ANALYSIS INDICATES A NEAR ZONAL FLOW ON THE NORTHERN PERIPHERY OF A WEAK RIDGE ACROSS THE OHIO VALLEY. AT THE SURFACE, A 1009MB LOW IS LOCATED ILLINOIS WITH A WARM FRONT EXTENDING EASTWARD ACROSS CENTRAL OHIO. A CONVECTIVE COMPLEX CONTINUES TO WEAKEN AS IT SLIDES SOUTHEAST ACROSS EASTERN OHIO. THIS EVENING...DRY AIR AT THE SURFACE, INDICATED BY TD DEPRESSIONS OF 25-30F SHOULD CONTINUE TO LIMIT THE EASTWARD PROGRESSION OF SHOWERS INTO THE AREA. THE WARM FRONT WILL CONTINUE TO PUSH INTO THE AREA FROM THE SOUTHWEST AS THE SURFACE LOW TREKS ACROSS THE OHIO VALLEY. THIS WILL ALLOW FOR TEMPS TO CONTINUE TO WARM INTO THE EVENING. TONIGHT...THE SURFACE LOW WILL MOVE INTO WESTERN PENNSYLVANIA AS THE WARM FRONT STRADDLES THE AREA. NAM/GFS INDICATE AN AREA OF WEAK ELEVATED INSTABILITY PUSHING ACROSS THE AREA AND ALLOWING FOR THE CHANCE OF THUNDERSTORMS PRIMARILY SOUTH OF THE PITTSBURGH METRO OVERNIGHT. BY DAWN, THE FRONTAL BOUNDARY WILL HAVE PUSHED SOUTHWARD TO THE MASON-DIXON LINE, WITH LINGERING SHOWERS ALONG AND SOUTH OF THE BOUNDARY. OVERNIGHT LOWS ARE A FEW DEGREES WARMER THAN LAMP GUIDANCE, RANGING FROM THE LOWER 40S NORTH OF THE BOUNDARY ALONG THE I-80 CORRIDOR TO THE MID 50S IN NORTH-CENTRAL WV. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... GFS/ECMWF EQUIV POT TEMP AND DEW POINT GRADIENTS INDICATE THE FRONTAL BOUNDARY SLIDING FROM THE MASON-DIXON LINE INTO CENTRAL WV BY 21Z FRIDAY. BEFORE THE BOUNDARY SHIFTS SOUTHWARD, NAM/GFS INDICATE ENOUGH INSTABILITY TO SUPPORT CHANCE OF THUNDER WEDNESDAY LATE MORNING INTO THE EARLY AFTERNOON ACROSS PORTIONS OF NORTH- CENTRAL WV. HIGH PRESSURE APPROACHING FROM THE NORTHWEST ALONG WITH DRIER AND STABLE AIR WILL ALLOW FOR A DRY FORECAST FOR THE REMAINDER OF THE DAY ACROSS THE AREA. HIGH TEMPS FOR WEDNESDAY ARE A FEW DEGREES ABOVE SEASONAL NORMALS. THERE IS OPERATIONAL MODEL AGREEMENT THAT A SURFACE HIGH WILL MOVE FROM CENTRAL CANADA INTO THE GREAT LAKES WEDNESDAY NIGHT INTO FRIDAY. THIS WILL ALLOW FOR CLEARING SKIES WEDNESDAY NIGHT AND ABUNDANT SUNSHINE THURSDAY AND FRIDAY. TEMPERATURES ARE FORECAST TO NEAR NORMAL SEASONAL VALUES EACH DAY. WITH THE HIGH FUNNELING IN COLDER, CANADIAN AIR, FREEZES WILL AGAIN BE POSSIBLE NORTHEAST OF PITTSBURGH ON THURSDAY AND FRIDAY MORNING. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS HIGH PRESSURE OVER THE EASTERN U.S. PROVIDING DRY CONDITIONS ACROSS THE UPPER OHIO VALLEY INTO AT LEAST SUNDAY AND PERHAPS MONDAY. THEN UPPER LEVEL RIDGE BUILDING ACROSS THE HIGH PLAINS OF CENTRAL CANADA AND THE U.S. THIS WILL CAUSE INCREASED NORTHWEST FLOW DOWNWIND INTO THE UPPER OHIO VALLEY, WITH A SHOWERY COLD FRONTAL PASSAGE EITHER MONDAY OR TUESDAY. REGARDING TEMPERATURES, EXPECT A LARGER THAN NORMAL DIURNAL RANGE SATURDAY DUE TO RELATIVELY CLEAR SKIES ENHANCING RADIATIVE EFFECTS. LOWS FRIDAY NIGHT CAN BE ABOUT 5 DEGREES COLDER THAN NORMAL, WHILE SATURDAY AFTERNOON HIGHS CAN BE UP TO 10 DEGREES WARMER THAN NORMAL. DUE TO COLD FRONTAL PASSAGE TIMING UNCERTAINTY, FORECASTED TEMPERATURES SUNDAY INTO MONDAY TO BE NEAR SEASONABLE. BY TUESDAY, THE POSTFRONTAL COOL DOWN WILL CAUSE TEMPERATURES TO BE AT LEAST 5 DEGREES COLDER THAN NORMAL. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... SKIES CLEAR TO SCT FIRST PART OF NIGHT. SEVERAL SREF MODEL OUTPUT MEMBERS SHOW A SECOND COMPLEX OF SHOWERS AND SCATTERED THUNDERSTORMS, WITH MVFR FLIGHT CONDITIONS, MOVING SOUTHEASTWARD ACROSS THE I-70 CORRIDOR AND AREAS SOUTH LATE TONIGHT INTO WEDNESDAY MORNING, 07Z-15Z, IN ASSOCIATION WITH THE PASSAGE OF A LOW PRESSURE CENTER AND COLD FRONT. POST FRONTAL DRYING WILL RESTORE VFR WEDNESDAY AFTERNOON. SURFACE WINDS BECOME NORTHWEST LATE TONIGHT AND WEDNESDAY AT 5 TO 10 KTS INCREASING TO 10 TO 15 KTS. OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY... EXPECT VFR DUE TO HIGH PRESSURE. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
346 PM EDT MON APR 2 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN FROM THE NORTH AND DROP TEMPERATURES TO NEAR FREEZING ACROSS PORTIONS OF THE AREA TONIGHT. A FRONTAL BOUNDARY WILL APPROACH FROM THE SOUTHWEST TOMORROW, BRINGING WARMER TEMPERATURES WITH THE CHANCE OF SHOWERS AND THUNDERSTORMS TOMORROW NIGHT. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... THE LATEST RUC 300MB ANALYSIS INDICATES RIDGING AND WEAK WINDS ALOFT BEGINNING TO BUILD INTO THE OHIO VALLEY FROM THE WEST AS A 140KT JET SLIDES EAST OF THE AREA INTO THE NORTHEAST. A SWATH OF DRY AIR IS EVIDENT SLIDING SOUTHEASTWARD ACROSS WESTERN PA. AT THE SURFACE, A 1025MB HIGH IS CENTERED OVER THE HUDSON BAY WITH HIGH PRESSURE EXTENDING SOUTHEASTWARD INTO THE GREAT LAKES. TONIGHT...THERE IS OPERATIONAL MODEL AGREEMENT THAT THE RIDGE WILL EDGE EASTWARD AND BECOME CENTERED OVER THE GREAT LAKES. A NORTHWESTERLY FLOW ALOFT WILL ALLOW FOR HIGH PRESSURE TO SLIDE FURTHER SOUTHWARD INTO THE UPPER OHIO VALLEY, BECOMING CENTERED NORTHEAST OF PITTSBURGH BY 12Z TUESDAY. THUS, CLEAR SKIES CAN BE EXPECTED UNTIL NEAR DAWN WHEN CIRRUS BEGINS TO SPILL INTO THE AREA FROM THE WEST. FOR TEMPS, A MAV/MET BLEND SEEMED REASONABLE WITH THE BEST RADIATIONAL COOLING TONIGHT CLOSEST TO THE SURFACE HIGH NORTHEAST OF PITTSBURGH. A FREEZE WARNING HAS BEEN ISSUED FOR AREAS NORTHEAST OF PITTSBURGH AND ACROSS THE EASTERN RIDGES. PATCHY FROST IS ALSO FORECAST FOR THE PITTSBURGH METRO. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... THERE IS NAM/ECMWF AGREEMENT THAT A MID-LEVEL SHORT WAVE ALONG WITH A WEAK SURFACE LOW WILL MOVE FROM THE MISSOURI VALLEY ACROSS THE OHIO VALLEY ON TUESDAY. THIS WILL ALLOW FOR A WARM FRONT TO APPROACH FROM THE SOUTHWEST DURING THE DAY. MODELS INDICATE THE SHORT WAVE DE-AMPLIFYING AND THE SURFACE LOW BECOMING POORLY DEFINED AS THE PAIR MOVE INTO THE AREA IN THE 00Z-06Z WEDNESDAY TIME FRAME. WITH THIS IN MIND, HAVE SLOWED POPS AND WILL KEEP THE FORECAST DRY UNTIL 21Z WHEN WEAK ELEVATED INSTABILITY BEGINS TO MOVE INTO EASTERN OHIO AND BRINGS THE POSSIBILITY OF THUNDERSTORMS. LINGERING WAVE ENERGY WILL PUSH ACROSS THE AREA AS THE FRONTAL BOUNDARY BECOMES STATIONARY. THUS, THE BEST CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE TUESDAY NIGHT. DESPITE THE FRONTAL BOUNDARY BEING SLOW TO APPROACH FROM THE SOUTHWEST, WARM AIR ADVECTION ALOFT WILL ALLOW FOR 850 TEMPS TO WARM INTO THE 10-14C RANGE BY 00Z WEDNESDAY. HIGHS TUESDAY ARE FORECAST AT 10 DEGREES ABOVE NORMAL. TUESDAY NIGHT TEMPS WILL BE SLOW TO DECREASE AS THE BOUNDARY MOVES NORTH INTO THE AREA. LOWS WILL RANGE FROM THE LOWER 50S ACROSS NORTH-CENTRAL WV TO NEAR 40 NORTH OF THE I-80 CORRIDOR. WEDNESDAY THROUGH THURSDAY...THE FRONTAL BOUNDARY WILL BEGIN TO SAG SOUTHWARD ON WEDNESDAY, WITH THE CHANCE OF SHOWERS ENDING ACROSS THE SOUTH BY THE AFTERNOON. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH WITH A DRY FORECAST THROUGH THURSDAY. TEMPERATURES THROUGH THIS PERIOD WILL BE NEAR SEASONAL VALUES WITH THE POTENTIAL FOR ANOTHER FREEZE NORTHEAST OF PITTSBURGH ON WEDNESDAY NIGHT. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS HIGH PRESSURE OVER THE EASTERN U.S. PROVIDING DRY CONDITIONS ACROSS THE UPPER OHIO VALLEY INTO DAYTIME SUNDAY. CONSENSUS OF MODELS THEN SHOW THE UPPER LEVEL JET STREAM PATTERN BECOMING MORE ZONAL WITH A SOUTHWEST ORIENTATION. THIS ZONAL UPPER FLOW WILL STEER A COLD FRONTAL BAND OF SHOWERS EASTWARD THROUGH THE UPPER OHIO VALLEY SUNDAY NIGHT INTO MONDAY. FORECASTED TEMPERATURES, USING BLEND OF GFS AND NAEFS MODEL OUTPUT, TO BE NEAR NORMAL FRIDAY, FOLLOWED BY A PREFRONTAL WARM UP SATURDAY AND SUNDAY TO VALUES UP TO 10 DEGREES ABOVE NORMAL. TEMPERATURES MONDAY SHOULD BE CLOSER TO NORMAL DUE TO CLOUDS AND SHOWERS AND POTENTIAL POSTFRONTAL COOLING, ALTHOUGH THE LATTER WILL BE LIMITED BY THE SOUTHWEST WINDS ALOFT. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... PER RECENT SURFACE AND SATELLITE DATA, EXPECT MAINLY CLEAR SKIES TONIGHT. SURFACE WINDS WILL BE FROM THE NORTH AND NORTHEAST AT NO MORE THAN 8 KTS THROUGH EARLY EVENING, THEN BECOME LIGHT TONIGHT. OUTLOOK...TUESDAY THROUGH SATURDAY... RESTRICTIONS POSSIBLE TUESDAY LATE AFTERNOON AND NIGHT WITH SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS. VFR WEDNESDAY THROUGH SATURDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZE WARNING FROM 2 AM TO 8 AM EDT TUESDAY FOR MDZ001. OH...NONE. PA...FREEZE WARNING FROM 2 AM TO 8 AM EDT TUESDAY FOR PAZ007>009- 013>016-022-023-074-076. WV...FREEZE WARNING FROM 2 AM TO 8 AM EDT TUESDAY FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
158 PM EDT MON APR 2 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN FROM THE NORTH TODAY AND DROP TEMPERATURES NEAR FREEZING TONIGHT ACROSS PORTIONS OF THE AREA. A FRONTAL BOUNDARY WILL APPROACH FROM THE SOUTHWEST TOMORROW, BRINGING WARMER TEMPERATURES WITH THE CHANCE OF SHOWERS AND THUNDERSTORMS TOMORROW NIGHT. && .NEAR TERM /THROUGH TONIGHT/... 18Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO CLEAR OUT THE SKY GRIDS THROUGH THE PRE-DAWN HOURS ON TUESDAY. THE LATEST RUC 300MB ANALYSIS INDICATES RIDGING AND WEAK WINDS ALOFT BEGINNING TO BUILD INTO THE OHIO VALLEY FROM THE WEST AS A 140KT JET SLIDES EAST OF THE AREA INTO THE NORTHEAST. A SWATH OF DRY AIR IS EVIDENT SLIDING SOUTHEASTWARD ACROSS WESTERN PA. AT THE SURFACE, A 1025MB HIGH IS CENTERED OVER THE HUDSON BAY WITH HIGH PRESSURE EXTENDING SOUTHEASTWARD INTO THE GREAT LAKES. TODAY AND TONIGHT...THERE IS OPERATIONAL MODEL AGREEMENT THAT THE RIDGE WILL EDGE EASTWARD AND BECOME CENTERED OVER THE GREAT LAKES. A NORTHWESTERLY FLOW ALOFT WILL ALLOW FOR HIGH PRESSURE TO SLIDE FURTHER SOUTHWARD INTO THE UPPER OHIO VALLEY, BECOMING CENTERED NORTHEAST OF PITTSBURGH BY 12Z TUESDAY. THUS, CLEAR SKIES CAN BE EXPECTED THROUGH THIS PERIOD. TEMPS ARE IN LINE WITH THE PREVIOUS FORECAST, SO FORECAST HIGHS CONTINUE TO BE A FEW DEGREES WARMER THAN A MAV/MET BLEND AND SEASONAL NORMS. THE BEST RADIATIONAL COOLING TONIGHT WILL OCCUR CLOSEST TO THE SURFACE HIGH, WHICH WILL BE NORTHEAST OF PITTSBURGH. CURRENTLY, THE MOST CONFIDENCE IN A FREEZE IS ALONG THE I-80 CORRIDOR. PATCHY FROST IS FORECAST FOR AREAS NORTHEAST OF PITTSBURGH AND ACROSS THE EASTERN RIDGES. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... HAVE MAINTAINED A FORECAST OF CHANCE SHOWERS AND THUNDERSTORMS IN THE WARM ADVECTION REGIME OF THE AFOREMENTIONED LOW PRESSURE SYSTEM ON TUESDAY AFTERNOON AND WITH THE COLD FRONT ON TUESDAY NIGHT. HIGH PRESSURE WILL FOLLOW WITH DRY AND COOLER CONDITIONS WEDNESDAY. THE SHORT TERM TEMPERATURE FORECAST WAS COMPLETED USING A BLEND OF GUIDANCE AND FEATURES READINGS FROM 5 TO 10 DEGREES ABOVE NORMAL TUESDAY...AND NEAR NORMAL FOR WEDNESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... DRY WEATHER SHOULD PREVAIL ACROSS THE UPPER OHIO VALLEY REGION INTO THE WEEKEND AS A LARGE AREA OF HIGH PRESSURE SLIDES SOUTHEAST ACROSS THE GREAT LAKES. A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK EASTWARD FROM THE LOWER MS VALLEY TO OFF SOUTHEAST COAST LATE IN THE WEEK. THE BULK OF ASSOCIATED MOISTURE IS PROGGED TO REMAIN SOUTH OF THE FORECAST AREA. HPC GUIDANCE SHOWS THE NEXT COLD FRONT APPROACHING FROM THE WEST WITH A CHANCE OF SHOWERS LATE SUNDAY. TEMPERATURES ARE FORECAST TO BE NEAR NORMAL THROUGH FRIDAY...THEN WARMING TO AROUND 10 DEGREES ABOVE NORMAL DURING THE WEEKEND. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... PER RECENT SURFACE AND SATELLITE DATA, EXPECT NO MORE THAN FEW VFR CUMULUS THIS AFTERNOON, THEN NO MORE THAN FEW CIRRUS TONIGHT. SURFACE WINDS WILL BE FROM THE NORTH AND NORTHEAST NO MORE THAN 10 KTS THIS AFTERNOON, GOING LIGHT TONIGHT. OUTLOOK...TUESDAY THROUGH SATURDAY... RESTRICTIONS POSSIBLE TUESDAY LATE AFTERNOON AND NIGHT WITH SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS. OTHERWISE VFR. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1120 AM EDT MON APR 2 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN FROM THE NORTH TODAY AND DROP TEMPERATURES NEAR FREEZING TONIGHT ACROSS PORTIONS OF THE AREA. A FRONTAL BOUNDARY WILL APPROACH FROM THE SOUTHWEST TOMORROW, BRINGING WARMER TEMPERATURES WITH THE CHANCE OF SHOWERS AND THUNDERSTORMS LATE IN THE DAY. && .NEAR TERM /THROUGH TONIGHT/... 15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO ACCOUNT FOR THE LATEST TRENDS IN TEMPS AND SKY. THE LATEST RUC 300MB ANALYSIS INDICATES RIDGING AND WEAK WINDS ALOFT BEGINNING TO BUILD INTO THE OHIO VALLEY FROM THE WEST AS A 140KT JET SLIDES EAST OF THE AREA INTO THE NORTHEAST. A SWATH OF DRY AIR ABOVE 850MB IS EVIDENT SLIDING SOUTHEASTWARD ACROSS WESTERN PA. AT THE SURFACE, A 1025MB HIGH IS CENTERED OVER THE HUDSON BAY WITH HIGH PRESSURE EXTENDING SOUTHEASTWARD INTO THE GREAT LAKES. A NORTHEASTERLY LOW-LEVEL FLOW IS PUSHING STRATOCUMULUS, WHICH IS DIMINISHING, SOUTHWEST OF THE PITTSBURGH METRO. TODAY AND TONIGHT...THERE IS OPERATIONAL MODEL AGREEMENT THAT THE RIDGE WILL EDGE EASTWARD AND BECOME CENTERED OVER THE GREAT LAKES. A NORTHWESTERLY FLOW ALOFT WILL ALLOW FOR HIGH PRESSURE TO SLIDE FURTHER SOUTHWARD INTO THE UPPER OHIO VALLEY, BECOMING CENTERED NORTHEAST OF PITTSBURGH BY 12Z TUESDAY. THUS, CLOUD COVERAGE WILL CONTINUE TO DIMINISH EARLY TODAY WITH CLEARING ACROSS THE AREA. TEMPS ARE IN LINE WITH THE PREVIOUS FORECAST, SO FORECAST HIGHS CONTINUE TO BE A FEW DEGREES WARMER THAN A MAV/MET BLEND AND SEASONAL NORMS. THE BEST RADIATIONAL COOLING TONIGHT WILL OCCUR CLOSEST TO THE SURFACE HIGH, WHICH WILL BE NORTHEAST OF PITTSBURGH. CURRENTLY, THE MOST CONFIDENCE IN A FREEZE IS ALONG THE I-80 CORRIDOR. PATCHY FROST IS FORECAST FOR AREAS NORTHEAST OF PITTSBURGH AND ACROSS THE EASTERN RIDGES. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... HAVE MAINTAINED A FORECAST OF CHANCE SHOWERS AND THUNDERSTORMS IN THE WARM ADVECTION REGIME OF THE AFOREMENTIONED LOW PRESSURE SYSTEM ON TUESDAY AFTERNOON AND WITH THE COLD FRONT ON TUESDAY NIGHT. HIGH PRESSURE WILL FOLLOW WITH DRY AND COOLER CONDITIONS WEDNESDAY. THE SHORT TERM TEMPERATURE FORECAST WAS COMPLETED USING A BLEND OF GUIDANCE AND FEATURES READINGS FROM 5 TO 10 DEGREES ABOVE NORMAL TUESDAY...AND NEAR NORMAL FOR WEDNESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... DRY WEATHER SHOULD PREVAIL ACROSS THE UPPER OHIO VALLEY REGION INTO THE WEEKEND AS A LARGE AREA OF HIGH PRESSURE SLIDES SOUTHEAST ACROSS THE GREAT LAKES. A SLOW MOVING LOW PRESSURE SYSTEM WILL TRACK EASTWARD FROM THE LOWER MS VALLEY TO OFF SOUTHEAST COAST LATE IN THE WEEK. THE BULK OF ASSOCIATED MOISTURE IS PROGGED TO REMAIN SOUTH OF THE FORECAST AREA. HPC GUIDANCE SHOWS THE NEXT COLD FRONT APPROACHING FROM THE WEST WITH A CHANCE OF SHOWERS LATE SUNDAY. TEMPERATURES ARE FORECAST TO BE NEAR NORMAL THROUGH FRIDAY...THEN WARMING TO AROUND 10 DEGREES ABOVE NORMAL DURING THE WEEKEND. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... PER RECENT SURFACE AND SATELLITE DATA, EXPECT POSTFRONTAL COLD POOL STRATOCUMULUS CLOUD BANK TO CONTINUE TO ERODE THIS MORNING, NORTHEAST TO SOUTHWEST. SO REMAINING MVFR CEILINGS SHOULD BE AT VFR LEVELS BY 16Z AND DISSIPATED BY 17Z. EXPECT VFR CLEAR SKIES TONIGHT. SURFACE WINDS WILL BE FROM THE NORTH AND NORTHEAST NEAR 10 KTS TODAY, THEN GO LIGHT TONIGHT. OUTLOOK...TUESDAY THROUGH FRIDAY... RESTRICTIONS POSSIBLE TUESDAY LATE AFTERNOON AND NIGHT WITH SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS. OTHERWISE VFR. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
145 PM EDT MON APR 2 2012 .UPDATE... ISSUED AT 1228 PM EDT MON APR 2 2012 BASED ON 12Z RAOB FROM KINL AND LOOKING AT NAM SNDG FOR KIWD FOR THIS AFTERNOON...I AM SKEPTICAL ABOUT SHRA/TSRA CHCS THIS AFTERNOON. DESPITE INCREASE IN WAA AT NOSE OF 30 KT 850 MB JET AND INCREASE IN 8H THETA-E VALUES BY LATE AFTERNOON...NAM MODEL SNDG FOR KIWD LIFTED AT 800 MB STILL INDICATED A CAP AT AROUND 650 MB WITH OVER 25 J/KG OF CIN AND LESS THAN 200 J/KG. THIS CAP IS ALSO REFLECTED IN 12Z KINL SNDG. AS A RESULT OF INSTABILITY BEING MARGINAL AT BEST...HAVE DECIDED TO TRIM BACK POPS TO SLIGHT CHC FOR GOGEBIC AND ONTONAGON THIS AFTERNOON AND REMOVE POPS FARTHER TO THE EAST. && .SYNOPSIS... ISSUED AT 515 AM EDT MON APR 2 2012 UPPER RIDGE BUILDS INTO THE AREA TODAY BUT MOISTURE ADVECTION AT H85/H7 IS ALREADY SPAWNING SHRA/TSRA FM NORTHERN MN INTO NW WI AND TOWARD FAR WESTERN UPR MI. WILL HAVE TO CONTEND WITH AT LEAST ISOLD SHRA/TSRA TODAY MAINLY OVR WEST THIRD OF CWA. BETTER CHANCE FOR RAIN ARRIVES LATER TONIGHT AS SFC LOW AND INVERTED TROUGH SLIDE ACROSS UPR MI. SOME RAIN LINGERS ON TUESDAY MORNING BUT AFTER THAT DRY WEATHER DOMINATES THE REST OF THE WEEK AS HIGH PRESSURE EXPANDS FM HUDSON BAY ACROSS THE GREAT LAKES REGION. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 515 AM EDT MON APR 2 2012 TODAY...UPPER RIDGE CONTINUES TO BUILD FM THE PLAINS INTO THE WESTERN GREAT LAKES THROUGH THE DAY WHILE AT THE SFC...HIGH OVR HUDSON BAY WILL EXPAND A RIDGE AXIS ACROSS MUCH OF MICHIGAN. AT FIRST GLANCE...DOES NOT APPEAR TO BE A FAVORABLE SETUP FOR MUCH PRECIPITATION TODAY OVR UPR MI...BUT CERTAINLY CANNOT IGNORE CLUSTER OF SHRA/TSRA THAT HAVE FORMED OVR NORTHERN MN INTO NORTHWEST WI THE LAST FEW HOURS. SHRA/TSRA SEEM TO BE RUNNING ALONG AND NORTH OF RIBBON OF HIGHER H7 DWPNTS AND ON NORTHERN EDGE OF STEEPER H7-H5 LAPSE RATES FM MN INTO WI. ONLY 00Z GUIDANCE THAT SHOWED TSRA AS FAR EAST AS IS CURRENTLY OCCURRING WAS HRRR. ALL OTHER GUIDANCE KEPT GENESIS REGION FOR SHRA/TSRA OVR WESTERN MN WHERE BETTER H85 THETA-E ADVECTION IS TAKING PLACE. FOLLOWING RUC13/NAM H7 DWPNTS/WINDS SUGGESTS THAT AT LEAST ISOLD TSRA WILL EASE INTO WESTERN THIRD OF CWA THIS MORNING BEFORE FADING AWAY AS RIBBON OF HIGHER H7 DWPNT WEAKENS. WILL KEEP POPS IN OVR WEST ALL DAY THOUGH AS RUC INDICATES HINT OF H7 MOISTURE AXIS COULD PERSIST INTO EARLY AFTN. DESPITE RESERVOIR OF H7-H5 LAPSE RATES AOA 8C/KM UPSTREAM...MINIMAL LARGE SCALE FORCING AND MARGINAL 3-6KM SHEAR /20KT OR SO/ SHOULD LEAD TO ONLY SLIM CHANCES OF SEEING HAIL WITH THESE STORMS. WILL NEED TO MONITOR TRENDS THIS MORNING THOUGH. BY LATE AFTN...EXPECT MAIN AREA OF SHRA/TSRA WEST OF UPR MI IN AREA OF GREATEST H85 TEMP/MOISTURE ADVECTION. OTHER ISSUE TODAY ESPECIALLY THIS MORNING IS FOG. FOR THE MOST PART THE FOG IS OVR HIGHER TERRAIN OF NCNTRL CWA AND HIGHER TERRAIN OF KEWEENAW. EVEN IN THESE AREAS MAIN IMPACT IS MORE OF STRATUS DECK WITH VARIABLE VSBY. EXPECT DRY ADVECTION OVR EASTERN UPR MI TO SPREAD EAST AND DIMINISH THE FOG BY MID MORNING /AS ALREADY HAS OCCURRED AT ERY EARLY THIS MORNING/. COVERAGE OF CLOUDS /LOWER AND MID/ BY MID AFTN COULD BE CHAOTIC WHICH WILL NO-DOUBT IMPACT HIGH TEMPS. SE GRADIENT WIND OFF THE LAKES SHOULD KEEP TEMPS IN CHECK EVEN IF DECENT AMOUNT OF SUNSHINE ENDS UP OCCURRING. EXPECT HIGHS TO MAINLY TOP OUT IN THE 50S...COOLER NCNTRL WITH UPSLOPE FLOW. GIVEN ENOUGH SUNSHINE SOME SPOTS MAY PUSH PAST 60 DEGREES...BUT NOT TOO MUCH HIGHER. TONIGHT...UPR RIDGE REMAINS IN TACT TO START THE EVENING THEN OVERNIGHT NORTHERN STREAM SHORTWAVE MOVES FM MANITOBA INTO NORTHWEST ONTARIO. AS THIS TROUGH APPROACHES...SFC LOW OVR THE PLAINS WILL LIFT INTO WESTERN GREAT LAKES WITH INVERTED SFC TROUGH AND H85 TROUGH SLIDING WEST TO EAST ACROSS UPR MI. MODELS HAVE TRENDED A BIT SLOWER WITH ARRIVAL OF UPR AND SFC TROUGH. PREVIOUS FCST HAD GOOD HANDLE ON TREND WITH HIGHER POPS OVERNIGHT. WHAT TO DO WITH POP COVERAGE IS MAIN ISSUE. BASED ON EXPECTED LARGE SCALE PATTERN AND FCST LOCATION OF HIGHER MUCAPE...WOULD FIGURE THAT HIGHEST POPS WOULD BE OVER LK SUPERIOR AND MAINLY TO SOUTH OF CWA. THOUGH CONVERGENCE FM INVERTED SFC TROUGH INTERSECTING S/SW FLOW AT H85 /DPWNTS AOA +10C/ SUPPORTS HIGHER POPS OVR CWA AS WELL. KEPT POPS HIGH CHANCE TO LIKELY AS THE INVERTED TROUGH SLIDES THROUGH CWA. TSRA CHANCES SEEM MINIMAL BASED ON MAIN MUCAPE STAYING OVR WI AND 850-300MB THICKNESSES ORIENTED WNW TO ESE. HOWEVER...IF CONVECTION MAINLY FIRES ON FAR NORTH EDGE OF HIGHER INSTABILITY /AS OCCURRED THIS MORNING/ THEN IT IS FEASIBLE THERE COULD BE COMPLEX OF TSRA AFFECTING PORTIONS OF CWA OVERNIGHT TONGIHT INTO EARLY TUESDAY MORNING. LIKELY WILL NOT KNOW IF THIS IS THE CASE UNTIL MAYBE LATE THIS EVENING OR OVERNIGHT TONIGHT. TUESDAY...SLOWER TREND OF TROUGH PASSAGE CONTINUES TO SHOW UP INTO TUESDAY AND HAVE DELAYED DIMINISHING POPS UNTIL EARLY TUESDAY AFTN. AT THIS POINT /COULD BE FURTHER SLOWER TREND/ HIGHEST POPS ON TUESDAY WILL BE THROUGH ROUGHLY 16Z /NOON EDT/ OVR EASTERN HALF OF CWA MAINLY TO EAST OF MARQUETTE AND IRON MOUNTAIN. KEPT SMALL CHANCES FOR TSRA IN PICTURE ALONG LK MICHIGAN IN THE MORNING UNTIL H85 WINDS VEER WEST PUSHING THE HIGHER H85 DWPNTS/INSTABILITY TO SOUTHEAST OF CWA. WINDS TURNING NORTH BEHIND THE TROUGH SHOULD KEEP CLOUDS IN OVR MUCH CWA THROUGH MUCH OF AFTN. DECREASING CLOUDS EXPECTED LATE AFTN THOUGH PER MODEL CONSENSUS OF RAPIDLY LOWERING DWPNTS AT H85 AND PER FCST SOUNDINGS. POSSIBLE THAT SOME LOW CLOUDS AND/OR FOG MAY TRY TO ADVECT ONSHORE SIMILAR TO WHAT OCCURRED SUNDAY AFTN. LATER SHIFTS CAN ADDRESS THIS IN MORE DETAIL AND ADD IF IT SEEMS REASONABLE. LOWERED TEMPS ESPECIALLY IN THE NORTH CWA DUE TO LATER DEPARTURE OF PCPN AND CLOUDS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 515 AM EDT MON APR 2 2012 HIGH PRESSURE SLIDING IN TUESDAY EVENING FROM MANITOBA AND EASTERN ND/WESTERN MN WILL BRING ABOUT A PROLONGED PERIOD OF DRY WEATHER. EXPECT THE HIGH TO PUSH OVER THE UPPER GREAT LAKES WEDNESDAY AFTERNOON...BEFORE STRENGTHENING ACROSS THE AREA THROUGH FRIDAY. GIVEN A SLIGHTLY SLOWER SOLUTION AND A LINGERING 500MB TROUGH OVERHEAD THROUGH WEDNESDAY EVENING...WILL KEEP WITH LINGERING CLOUDS EAST INITIALLY TUESDAY NIGHT...AND AFTERNOON CLOUDS DEVELOPING NEAR 900MB POSSIBLE CENTRAL AND EAST. EXPECT ONLY LIMITED CLOUDS AT THIS TIME GIVEN OUR DRY ATMOSPHERE WITH PW VALUES ABOUT 60 PERCENT OF NORMAL AROUND 0.26IN. LOWERED DEW POINTS A COUPLE OF DEGREES FOR WEDNESDAY AFTERNOON...MAINLY INTERIOR WEST...WITH RH VALUES ACROSS THIS AREA BOTTOMING OUT AROUND 25 TO 30 PERCENT. WITH NO SIGNIFICANT INFLUX OF MOISTURE...RH VALUES SHOULD FALL BETWEEN 25 AND 35 PERCENT THROUGH FRIDAY /ONCE AGAIN MAINLY ACROSS THE INTERIOR WEST HALF/. LOW PRESSURE DEVELOPING OFF THE NORTHERN ROCKIES MID WEEK SHOULD PUSH ACROSS THE PLAINS STATES FRIDAY NIGHT...BEFORE SLIDING DEEPENING TO OUR WEST SATURDAY...AND PUSHING UP AND ACROSS ONTARIO SATURDAY NIGHT INTO SUNDAY. THE FORECAST MODELS LOOK TO BE IN FAIRLY GOOD AGREEMENT UNTIL THE FOCUS SHIFTS TO THE NEARING LOW SATURDAY AFTERNOON. AFTER SATURDAY...I HAVE ONLY MODERATE CONFIDENCE IN THE ONGOING FORECAST /MAINLY WITH RESPECT TO TIMING AND PRECIPITATION TYPE AS THE LOW EXITS/. AFTERNOON TS SATURDAY MAY LINGER INTO SATURDAY NIGHT EAST. WHILE THE QUICKER 01/12Z RUN OF THE ECMWF WOULD HAVE THEM OUT OF ERY BY 06Z SUNDAY. WILL TAKE OUT ANY MENTION OF WRAP AROUND SHSN SUNDAY...BUT IT MAY NEED TO BE ADDED BACK IN IF THE ECMWF VERIFIES WITH 850MB TEMPS FALLING TO AROUND -3 OR -4C BY EARLY AFTERNOON WEST AND CENTRAL. INSTEAD OF RUNNING A NON-DIURNAL TEMP TRACE FOR SUNDAY...KEPT WITH TRADITIONAL RISING TEMPS DURING THE DAY /SIMILAR TO THE GFS/. AS NOTED...THIS WILL LIKELY BE REVISED MORE THAN A FEW TIMES BEFORE OVER THE NEXT FEW DAYS AS FCST MODELS MERGE ON A SOLUTION...SO WILL NOT GET TOO SPECIFIC AT THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 143 PM EDT MON APR 2 2012 SUNSHINE AND ASSOC MIXING OVER THE TAF SITES TODAY ALONG WITH AN INCREASE IN MID CLOUD COVER FROM THE WEST THIS EVENING SHOULD PREVENT THE DEVELOPMENT OF LOW CLOUDS AND FOG TONIGHT. EXPECT VFR CONDITIONS TO CONTINUE AT ALL THE TAF SITES UNTIL LATE TONIGHT INTO WEDNESDAY WHEN WINDS COME AROUND TO THE NNW BEHIND FRONTAL BOUNDARY MOVING THROUGH THE AREA. DUE TO WEAK FORCING ALONG THE FRONTAL BOUNDARY...SHOWER COVERAGE WILL LIKELY BE SCATTERED AND FAIRLY LIGHT. ALSO THERE IS LESS CERTAINTY THAT SHOWERS WILL BE THE PREVAILING CONDITION AT THE TAF SITES TONIGHT INTO WEDNESDAY EXCEPT FOR MAYBE KIWD WHICH COULD SEE SOME AFTERNOON CONVECTION MOVE IN THERE THIS EVENING. AT KCMX AND KSAW WILL CONTINUE MENTION OF JUST VICINITY SHRA IN TAF. NOT EXPECTING MUCH REDUCTION IN VSBY FROM ANY OF THE SHOWERS...BUT COULD SEE AN MVFR CLOUD DECK DEVELOP IN THE WAKE OF THE FRONTAL BOUNDARY LATE TONIGHT AND WED. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 515 AM EDT MON APR 2 2012 WINDS SHOULD REMAIN BELOW 30KTS THROUGH AT LEAST FRIDAY. AN EXITING RIDGE OVER LAKE HURON WILL DRIFT ACROSS THE LOWER GREAT LAKES TODAY. IN ITS PLACE...A TROUGH WILL SLIDE IN FOR LATE TONIGHT INTO TUESDAY MORNING. EXPECT A HIGH OVER THE NORTHERN PLAINS AND CENTRAL CANADA TUESDAY TO SLOWLY SLIDE OVER LS WEDNESDAY...WHERE IT SHOULD REMAIN THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...VOSS SYNOPSIS...JLA SHORT TERM...JLA LONG TERM...KF AVIATION...VOSS MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1230 PM EDT MON APR 2 2012 .UPDATE... ISSUED AT 1228 PM EDT MON APR 2 2012 BASED ON 12Z RAOB FROM KINL AND LOOKING AT NAM SNDG FOR KIWD FOR THIS AFTERNOON...I AM SKEPTICAL ABOUT SHRA/TSRA CHCS THIS AFTERNOON. DESPITE INCREASE IN WAA AT NOSE OF 30 KT 850 MB JET AND INCREASE IN 8H THETA-E VALUES BY LATE AFTERNOON...NAM MODEL SNDG FOR KIWD LIFTED AT 800 MB STILL INDICATED A CAP AT AROUND 650 MB WITH OVER 25 J/KG OF CIN AND LESS THAN 200 J/KG. THIS CAP IS ALSO REFLECTED IN 12Z KINL SNDG. AS A RESULT OF INSTABILITY BEING MARGINAL AT BEST...HAVE DECIDED TO TRIM BACK POPS TO SLIGHT CHC FOR GOGEBIC AND ONTONAGON THIS AFTERNOON AND REMOVE POPS FARTHER TO THE EAST. && .SYNOPSIS... ISSUED AT 515 AM EDT MON APR 2 2012 UPPER RIDGE BUILDS INTO THE AREA TODAY BUT MOISTURE ADVECTION AT H85/H7 IS ALREADY SPAWNING SHRA/TSRA FM NORTHERN MN INTO NW WI AND TOWARD FAR WESTERN UPR MI. WILL HAVE TO CONTEND WITH AT LEAST ISOLD SHRA/TSRA TODAY MAINLY OVR WEST THIRD OF CWA. BETTER CHANCE FOR RAIN ARRIVES LATER TONIGHT AS SFC LOW AND INVERTED TROUGH SLIDE ACROSS UPR MI. SOME RAIN LINGERS ON TUESDAY MORNING BUT AFTER THAT DRY WEATHER DOMINATES THE REST OF THE WEEK AS HIGH PRESSURE EXPANDS FM HUDSON BAY ACROSS THE GREAT LAKES REGION. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 515 AM EDT MON APR 2 2012 TODAY...UPPER RIDGE CONTINUES TO BUILD FM THE PLAINS INTO THE WESTERN GREAT LAKES THROUGH THE DAY WHILE AT THE SFC...HIGH OVR HUDSON BAY WILL EXPAND A RIDGE AXIS ACROSS MUCH OF MICHIGAN. AT FIRST GLANCE...DOES NOT APPEAR TO BE A FAVORABLE SETUP FOR MUCH PRECIPITATION TODAY OVR UPR MI...BUT CERTAINLY CANNOT IGNORE CLUSTER OF SHRA/TSRA THAT HAVE FORMED OVR NORTHERN MN INTO NORTHWEST WI THE LAST FEW HOURS. SHRA/TSRA SEEM TO BE RUNNING ALONG AND NORTH OF RIBBON OF HIGHER H7 DWPNTS AND ON NORTHERN EDGE OF STEEPER H7-H5 LAPSE RATES FM MN INTO WI. ONLY 00Z GUIDANCE THAT SHOWED TSRA AS FAR EAST AS IS CURRENTLY OCCURRING WAS HRRR. ALL OTHER GUIDANCE KEPT GENESIS REGION FOR SHRA/TSRA OVR WESTERN MN WHERE BETTER H85 THETA-E ADVECTION IS TAKING PLACE. FOLLOWING RUC13/NAM H7 DWPNTS/WINDS SUGGESTS THAT AT LEAST ISOLD TSRA WILL EASE INTO WESTERN THIRD OF CWA THIS MORNING BEFORE FADING AWAY AS RIBBON OF HIGHER H7 DWPNT WEAKENS. WILL KEEP POPS IN OVR WEST ALL DAY THOUGH AS RUC INDICATES HINT OF H7 MOISTURE AXIS COULD PERSIST INTO EARLY AFTN. DESPITE RESERVOIR OF H7-H5 LAPSE RATES AOA 8C/KM UPSTREAM...MINIMAL LARGE SCALE FORCING AND MARGINAL 3-6KM SHEAR /20KT OR SO/ SHOULD LEAD TO ONLY SLIM CHANCES OF SEEING HAIL WITH THESE STORMS. WILL NEED TO MONITOR TRENDS THIS MORNING THOUGH. BY LATE AFTN...EXPECT MAIN AREA OF SHRA/TSRA WEST OF UPR MI IN AREA OF GREATEST H85 TEMP/MOISTURE ADVECTION. OTHER ISSUE TODAY ESPECIALLY THIS MORNING IS FOG. FOR THE MOST PART THE FOG IS OVR HIGHER TERRAIN OF NCNTRL CWA AND HIGHER TERRAIN OF KEWEENAW. EVEN IN THESE AREAS MAIN IMPACT IS MORE OF STRATUS DECK WITH VARIABLE VSBY. EXPECT DRY ADVECTION OVR EASTERN UPR MI TO SPREAD EAST AND DIMINISH THE FOG BY MID MORNING /AS ALREADY HAS OCCURRED AT ERY EARLY THIS MORNING/. COVERAGE OF CLOUDS /LOWER AND MID/ BY MID AFTN COULD BE CHAOTIC WHICH WILL NO-DOUBT IMPACT HIGH TEMPS. SE GRADIENT WIND OFF THE LAKES SHOULD KEEP TEMPS IN CHECK EVEN IF DECENT AMOUNT OF SUNSHINE ENDS UP OCCURRING. EXPECT HIGHS TO MAINLY TOP OUT IN THE 50S...COOLER NCNTRL WITH UPSLOPE FLOW. GIVEN ENOUGH SUNSHINE SOME SPOTS MAY PUSH PAST 60 DEGREES...BUT NOT TOO MUCH HIGHER. TONIGHT...UPR RIDGE REMAINS IN TACT TO START THE EVENING THEN OVERNIGHT NORTHERN STREAM SHORTWAVE MOVES FM MANITOBA INTO NORTHWEST ONTARIO. AS THIS TROUGH APPROACHES...SFC LOW OVR THE PLAINS WILL LIFT INTO WESTERN GREAT LAKES WITH INVERTED SFC TROUGH AND H85 TROUGH SLIDING WEST TO EAST ACROSS UPR MI. MODELS HAVE TRENDED A BIT SLOWER WITH ARRIVAL OF UPR AND SFC TROUGH. PREVIOUS FCST HAD GOOD HANDLE ON TREND WITH HIGHER POPS OVERNIGHT. WHAT TO DO WITH POP COVERAGE IS MAIN ISSUE. BASED ON EXPECTED LARGE SCALE PATTERN AND FCST LOCATION OF HIGHER MUCAPE...WOULD FIGURE THAT HIGHEST POPS WOULD BE OVER LK SUPERIOR AND MAINLY TO SOUTH OF CWA. THOUGH CONVERGENCE FM INVERTED SFC TROUGH INTERSECTING S/SW FLOW AT H85 /DPWNTS AOA +10C/ SUPPORTS HIGHER POPS OVR CWA AS WELL. KEPT POPS HIGH CHANCE TO LIKELY AS THE INVERTED TROUGH SLIDES THROUGH CWA. TSRA CHANCES SEEM MINIMAL BASED ON MAIN MUCAPE STAYING OVR WI AND 850-300MB THICKNESSES ORIENTED WNW TO ESE. HOWEVER...IF CONVECTION MAINLY FIRES ON FAR NORTH EDGE OF HIGHER INSTABILITY /AS OCCURRED THIS MORNING/ THEN IT IS FEASIBLE THERE COULD BE COMPLEX OF TSRA AFFECTING PORTIONS OF CWA OVERNIGHT TONGIHT INTO EARLY TUESDAY MORNING. LIKELY WILL NOT KNOW IF THIS IS THE CASE UNTIL MAYBE LATE THIS EVENING OR OVERNIGHT TONIGHT. TUESDAY...SLOWER TREND OF TROUGH PASSAGE CONTINUES TO SHOW UP INTO TUESDAY AND HAVE DELAYED DIMINISHING POPS UNTIL EARLY TUESDAY AFTN. AT THIS POINT /COULD BE FURTHER SLOWER TREND/ HIGHEST POPS ON TUESDAY WILL BE THROUGH ROUGHLY 16Z /NOON EDT/ OVR EASTERN HALF OF CWA MAINLY TO EAST OF MARQUETTE AND IRON MOUNTAIN. KEPT SMALL CHANCES FOR TSRA IN PICTURE ALONG LK MICHIGAN IN THE MORNING UNTIL H85 WINDS VEER WEST PUSHING THE HIGHER H85 DWPNTS/INSTABILITY TO SOUTHEAST OF CWA. WINDS TURNING NORTH BEHIND THE TROUGH SHOULD KEEP CLOUDS IN OVR MUCH CWA THROUGH MUCH OF AFTN. DECREASING CLOUDS EXPECTED LATE AFTN THOUGH PER MODEL CONSENSUS OF RAPIDLY LOWERING DWPNTS AT H85 AND PER FCST SOUNDINGS. POSSIBLE THAT SOME LOW CLOUDS AND/OR FOG MAY TRY TO ADVECT ONSHORE SIMILAR TO WHAT OCCURRED SUNDAY AFTN. LATER SHIFTS CAN ADDRESS THIS IN MORE DETAIL AND ADD IF IT SEEMS REASONABLE. LOWERED TEMPS ESPECIALLY IN THE NORTH CWA DUE TO LATER DEPARTURE OF PCPN AND CLOUDS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 515 AM EDT MON APR 2 2012 HIGH PRESSURE SLIDING IN TUESDAY EVENING FROM MANITOBA AND EASTERN ND/WESTERN MN WILL BRING ABOUT A PROLONGED PERIOD OF DRY WEATHER. EXPECT THE HIGH TO PUSH OVER THE UPPER GREAT LAKES WEDNESDAY AFTERNOON...BEFORE STRENGTHENING ACROSS THE AREA THROUGH FRIDAY. GIVEN A SLIGHTLY SLOWER SOLUTION AND A LINGERING 500MB TROUGH OVERHEAD THROUGH WEDNESDAY EVENING...WILL KEEP WITH LINGERING CLOUDS EAST INITIALLY TUESDAY NIGHT...AND AFTERNOON CLOUDS DEVELOPING NEAR 900MB POSSIBLE CENTRAL AND EAST. EXPECT ONLY LIMITED CLOUDS AT THIS TIME GIVEN OUR DRY ATMOSPHERE WITH PW VALUES ABOUT 60 PERCENT OF NORMAL AROUND 0.26IN. LOWERED DEW POINTS A COUPLE OF DEGREES FOR WEDNESDAY AFTERNOON...MAINLY INTERIOR WEST...WITH RH VALUES ACROSS THIS AREA BOTTOMING OUT AROUND 25 TO 30 PERCENT. WITH NO SIGNIFICANT INFLUX OF MOISTURE...RH VALUES SHOULD FALL BETWEEN 25 AND 35 PERCENT THROUGH FRIDAY /ONCE AGAIN MAINLY ACROSS THE INTERIOR WEST HALF/. LOW PRESSURE DEVELOPING OFF THE NORTHERN ROCKIES MID WEEK SHOULD PUSH ACROSS THE PLAINS STATES FRIDAY NIGHT...BEFORE SLIDING DEEPENING TO OUR WEST SATURDAY...AND PUSHING UP AND ACROSS ONTARIO SATURDAY NIGHT INTO SUNDAY. THE FORECAST MODELS LOOK TO BE IN FAIRLY GOOD AGREEMENT UNTIL THE FOCUS SHIFTS TO THE NEARING LOW SATURDAY AFTERNOON. AFTER SATURDAY...I HAVE ONLY MODERATE CONFIDENCE IN THE ONGOING FORECAST /MAINLY WITH RESPECT TO TIMING AND PRECIPITATION TYPE AS THE LOW EXITS/. AFTERNOON TS SATURDAY MAY LINGER INTO SATURDAY NIGHT EAST. WHILE THE QUICKER 01/12Z RUN OF THE ECMWF WOULD HAVE THEM OUT OF ERY BY 06Z SUNDAY. WILL TAKE OUT ANY MENTION OF WRAP AROUND SHSN SUNDAY...BUT IT MAY NEED TO BE ADDED BACK IN IF THE ECMWF VERIFIES WITH 850MB TEMPS FALLING TO AROUND -3 OR -4C BY EARLY AFTERNOON WEST AND CENTRAL. INSTEAD OF RUNNING A NON-DIURNAL TEMP TRACE FOR SUNDAY...KEPT WITH TRADITIONAL RISING TEMPS DURING THE DAY /SIMILAR TO THE GFS/. AS NOTED...THIS WILL LIKELY BE REVISED MORE THAN A FEW TIMES BEFORE OVER THE NEXT FEW DAYS AS FCST MODELS MERGE ON A SOLUTION...SO WILL NOT GET TOO SPECIFIC AT THIS TIME. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 632 AM EDT MON APR 2 2012 LOW CLOUDS AND SOME FOG WILL AFFECT CMX AND SAW THROUGH MID MORNING. MAIN IMPACT WILL BE CIGS BLO ALTERNATE AIRPORT MINS BUT BRIEF VSBY OF LIFR/IFR POSSIBLE AS WELL. PROBLEM AT IWD WILL BE SHRA/ISOLD TSRA THROUGH MID MORNING. COULD SEE BRIEF VSBY REDUCTIONS BUT SHOULD ONLY BE MVFR BASED ON UPSTREAM OBSERVATIONS AND SINCE SE WIND DIRECTION IS NOT FAVORABLE FOR ANY ADDITIONAL LIFTING VIA UPSLOPE. EXPECT ALL TAF SITES TO BE VFR BY EARLY AFTN WITH SCT-BKN MID CLOUDS. MAIN FRONT AND SFC LOW COME ACROSS UPR MICHIGAN TONIGHT. SCT LINE OF SHRA AND PERHAPS A TSRA AS WELL WILL SLIDE WEST-TO-EAST LATER IN THE EVENING THROUGH THE OVERNIGHT HOURS. MODELS VARY ON EXACT DEPICTION OF RAIN WITH FROPA SO KEPT WITH BROADBRUSHED DEPICTION FOR THE TIMING OF THE RAIN. POTENTIAL FOR SIGNIFICANT REDUCTION TO CIGS/VSBY WITH ANY SHOWERS DOES APPEAR REMOTE RIGHT NOW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 515 AM EDT MON APR 2 2012 WINDS SHOULD REMAIN BELOW 30KTS THROUGH AT LEAST FRIDAY. AN EXITING RIDGE OVER LAKE HURON WILL DRIFT ACROSS THE LOWER GREAT LAKES TODAY. IN ITS PLACE...A TROUGH WILL SLIDE IN FOR LATE TONIGHT INTO TUESDAY MORNING. EXPECT A HIGH OVER THE NORTHERN PLAINS AND CENTRAL CANADA TUESDAY TO SLOWLY SLIDE OVER LS WEDNESDAY...WHERE IT SHOULD REMAIN THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...VOSS SYNOPSIS...JLA SHORT TERM...JLA LONG TERM...KF AVIATION...JLA MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
633 AM EDT MON APR 2 2012 .SYNOPSIS... ISSUED AT 515 AM EDT MON APR 2 2012 UPPER RIDGE BUILDS INTO THE AREA TODAY BUT MOISTURE ADVECTION AT H85/H7 IS ALREADY SPAWNING SHRA/TSRA FM NORTHERN MN INTO NW WI AND TOWARD FAR WESTERN UPR MI. WILL HAVE TO CONTEND WITH AT LEAST ISOLD SHRA/TSRA TODAY MAINLY OVR WEST THIRD OF CWA. BETTER CHANCE FOR RAIN ARRIVES LATER TONIGHT AS SFC LOW AND INVERTED TROUGH SLIDE ACROSS UPR MI. SOME RAIN LINGERS ON TUESDAY MORNING BUT AFTER THAT DRY WEATHER DOMINATES THE REST OF THE WEEK AS HIGH PRESSURE EXPANDS FM HUDSON BAY ACROSS THE GREAT LAKES REGION. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 515 AM EDT MON APR 2 2012 TODAY...UPPER RIDGE CONTINUES TO BUILD FM THE PLAINS INTO THE WESTERN GREAT LAKES THROUGH THE DAY WHILE AT THE SFC...HIGH OVR HUDSON BAY WILL EXPAND A RIDGE AXIS ACROSS MUCH OF MICHIGAN. AT FIRST GLANCE...DOES NOT APPEAR TO BE A FAVORABLE SETUP FOR MUCH PRECIPITATION TODAY OVR UPR MI...BUT CERTAINLY CANNOT IGNORE CLUSTER OF SHRA/TSRA THAT HAVE FORMED OVR NORTHERN MN INTO NORTHWEST WI THE LAST FEW HOURS. SHRA/TSRA SEEM TO BE RUNNING ALONG AND NORTH OF RIBBON OF HIGHER H7 DWPNTS AND ON NORTHERN EDGE OF STEEPER H7-H5 LAPSE RATES FM MN INTO WI. ONLY 00Z GUIDANCE THAT SHOWED TSRA AS FAR EAST AS IS CURRENTLY OCCURRING WAS HRRR. ALL OTHER GUIDANCE KEPT GENESIS REGION FOR SHRA/TSRA OVR WESTERN MN WHERE BETTER H85 THETA-E ADVECTION IS TAKING PLACE. FOLLOWING RUC13/NAM H7 DWPNTS/WINDS SUGGESTS THAT AT LEAST ISOLD TSRA WILL EASE INTO WESTERN THIRD OF CWA THIS MORNING BEFORE FADING AWAY AS RIBBON OF HIGHER H7 DWPNT WEAKENS. WILL KEEP POPS IN OVR WEST ALL DAY THOUGH AS RUC INDICATES HINT OF H7 MOISTURE AXIS COULD PERSIST INTO EARLY AFTN. DESPITE RESERVOIR OF H7-H5 LAPSE RATES AOA 8C/KM UPSTREAM...MINIMAL LARGE SCALE FORCING AND MARGINAL 3-6KM SHEAR /20KT OR SO/ SHOULD LEAD TO ONLY SLIM CHANCES OF SEEING HAIL WITH THESE STORMS. WILL NEED TO MONITOR TRENDS THIS MORNING THOUGH. BY LATE AFTN...EXPECT MAIN AREA OF SHRA/TSRA WEST OF UPR MI IN AREA OF GREATEST H85 TEMP/MOISTURE ADVECTION. OTHER ISSUE TODAY ESPECIALLY THIS MORNING IS FOG. FOR THE MOST PART THE FOG IS OVR HIGHER TERRAIN OF NCNTRL CWA AND HIGHER TERRAIN OF KEWEENAW. EVEN IN THESE AREAS MAIN IMPACT IS MORE OF STRATUS DECK WITH VARIABLE VSBY. EXPECT DRY ADVECTION OVR EASTERN UPR MI TO SPREAD EAST AND DIMINISH THE FOG BY MID MORNING /AS ALREADY HAS OCCURRED AT ERY EARLY THIS MORNING/. COVERAGE OF CLOUDS /LOWER AND MID/ BY MID AFTN COULD BE CHAOTIC WHICH WILL NO-DOUBT IMPACT HIGH TEMPS. SE GRADIENT WIND OFF THE LAKES SHOULD KEEP TEMPS IN CHECK EVEN IF DECENT AMOUNT OF SUNSHINE ENDS UP OCCURRING. EXPECT HIGHS TO MAINLY TOP OUT IN THE 50S...COOLER NCNTRL WITH UPSLOPE FLOW. GIVEN ENOUGH SUNSHINE SOME SPOTS MAY PUSH PAST 60 DEGREES...BUT NOT TOO MUCH HIGHER. TONIGHT...UPR RIDGE REMAINS IN TACT TO START THE EVENING THEN OVERNIGHT NORTHERN STREAM SHORTWAVE MOVES FM MANITOBA INTO NORTHWEST ONTARIO. AS THIS TROUGH APPROACHES...SFC LOW OVR THE PLAINS WILL LIFT INTO WESTERN GREAT LAKES WITH INVERTED SFC TROUGH AND H85 TROUGH SLIDING WEST TO EAST ACROSS UPR MI. MODELS HAVE TRENDED A BIT SLOWER WITH ARRIVAL OF UPR AND SFC TROUGH. PREVIOUS FCST HAD GOOD HANDLE ON TREND WITH HIGHER POPS OVERNIGHT. WHAT TO DO WITH POP COVERAGE IS MAIN ISSUE. BASED ON EXPECTED LARGE SCALE PATTERN AND FCST LOCATION OF HIGHER MUCAPE...WOULD FIGURE THAT HIGHEST POPS WOULD BE OVER LK SUPERIOR AND MAINLY TO SOUTH OF CWA. THOUGH CONVERGENCE FM INVERTED SFC TROUGH INTERSECTING S/SW FLOW AT H85 /DPWNTS AOA +10C/ SUPPORTS HIGHER POPS OVR CWA AS WELL. KEPT POPS HIGH CHANCE TO LIKELY AS THE INVERTED TROUGH SLIDES THROUGH CWA. TSRA CHANCES SEEM MINIMAL BASED ON MAIN MUCAPE STAYING OVR WI AND 850-300MB THICKNESSES ORIENTED WNW TO ESE. HOWEVER...IF CONVECTION MAINLY FIRES ON FAR NORTH EDGE OF HIGHER INSTABILITY /AS OCCURRED THIS MORNING/ THEN IT IS FEASIBLE THERE COULD BE COMPLEX OF TSRA AFFECTING PORTIONS OF CWA OVERNIGHT TONGIHT INTO EARLY TUESDAY MORNING. LIKELY WILL NOT KNOW IF THIS IS THE CASE UNTIL MAYBE LATE THIS EVENING OR OVERNIGHT TONIGHT. TUESDAY...SLOWER TREND OF TROUGH PASSAGE CONTINUES TO SHOW UP INTO TUESDAY AND HAVE DELAYED DIMINISHING POPS UNTIL EARLY TUESDAY AFTN. AT THIS POINT /COULD BE FURTHER SLOWER TREND/ HIGHEST POPS ON TUESDAY WILL BE THROUGH ROUGHLY 16Z /NOON EDT/ OVR EASTERN HALF OF CWA MAINLY TO EAST OF MARQUETTE AND IRON MOUNTAIN. KEPT SMALL CHANCES FOR TSRA IN PICTURE ALONG LK MICHIGAN IN THE MORNING UNTIL H85 WINDS VEER WEST PUSHING THE HIGHER H85 DWPNTS/INSTABILITY TO SOUTHEAST OF CWA. WINDS TURNING NORTH BEHIND THE TROUGH SHOULD KEEP CLOUDS IN OVR MUCH CWA THROUGH MUCH OF AFTN. DECREASING CLOUDS EXPECTED LATE AFTN THOUGH PER MODEL CONSENSUS OF RAPIDLY LOWERING DWPNTS AT H85 AND PER FCST SOUNDINGS. POSSIBLE THAT SOME LOW CLOUDS AND/OR FOG MAY TRY TO ADVECT ONSHORE SIMILAR TO WHAT OCCURRED SUNDAY AFTN. LATER SHIFTS CAN ADDRESS THIS IN MORE DETAIL AND ADD IF IT SEEMS REASONABLE. LOWERED TEMPS ESPECIALLY IN THE NORTH CWA DUE TO LATER DEPARTURE OF PCPN AND CLOUDS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 515 AM EDT MON APR 2 2012 HIGH PRESSURE SLIDING IN TUESDAY EVENING FROM MANITOBA AND EASTERN ND/WESTERN MN WILL BRING ABOUT A PROLONGED PERIOD OF DRY WEATHER. EXPECT THE HIGH TO PUSH OVER THE UPPER GREAT LAKES WEDNESDAY AFTERNOON...BEFORE STRENGTHENING ACROSS THE AREA THROUGH FRIDAY. GIVEN A SLIGHTLY SLOWER SOLUTION AND A LINGERING 500MB TROUGH OVERHEAD THROUGH WEDNESDAY EVENING...WILL KEEP WITH LINGERING CLOUDS EAST INITIALLY TUESDAY NIGHT...AND AFTERNOON CLOUDS DEVELOPING NEAR 900MB POSSIBLE CENTRAL AND EAST. EXPECT ONLY LIMITED CLOUDS AT THIS TIME GIVEN OUR DRY ATMOSPHERE WITH PW VALUES ABOUT 60 PERCENT OF NORMAL AROUND 0.26IN. LOWERED DEW POINTS A COUPLE OF DEGREES FOR WEDNESDAY AFTERNOON...MAINLY INTERIOR WEST...WITH RH VALUES ACROSS THIS AREA BOTTOMING OUT AROUND 25 TO 30 PERCENT. WITH NO SIGNIFICANT INFLUX OF MOISTURE...RH VALUES SHOULD FALL BETWEEN 25 AND 35 PERCENT THROUGH FRIDAY /ONCE AGAIN MAINLY ACROSS THE INTERIOR WEST HALF/. LOW PRESSURE DEVELOPING OFF THE NORTHERN ROCKIES MID WEEK SHOULD PUSH ACROSS THE PLAINS STATES FRIDAY NIGHT...BEFORE SLIDING DEEPENING TO OUR WEST SATURDAY...AND PUSHING UP AND ACROSS ONTARIO SATURDAY NIGHT INTO SUNDAY. THE FORECAST MODELS LOOK TO BE IN FAIRLY GOOD AGREEMENT UNTIL THE FOCUS SHIFTS TO THE NEARING LOW SATURDAY AFTERNOON. AFTER SATURDAY...I HAVE ONLY MODERATE CONFIDENCE IN THE ONGOING FORECAST /MAINLY WITH RESPECT TO TIMING AND PRECIPITATION TYPE AS THE LOW EXITS/. AFTERNOON TS SATURDAY MAY LINGER INTO SATURDAY NIGHT EAST. WHILE THE QUICKER 01/12Z RUN OF THE ECMWF WOULD HAVE THEM OUT OF ERY BY 06Z SUNDAY. WILL TAKE OUT ANY MENTION OF WRAP AROUND SHSN SUNDAY...BUT IT MAY NEED TO BE ADDED BACK IN IF THE ECMWF VERIFIES WITH 850MB TEMPS FALLING TO AROUND -3 OR -4C BY EARLY AFTERNOON WEST AND CENTRAL. INSTEAD OF RUNNING A NON-DIURNAL TEMP TRACE FOR SUNDAY...KEPT WITH TRADITIONAL RISING TEMPS DURING THE DAY /SIMILAR TO THE GFS/. AS NOTED...THIS WILL LIKELY BE REVISED MORE THAN A FEW TIMES BEFORE OVER THE NEXT FEW DAYS AS FCST MODELS MERGE ON A SOLUTION...SO WILL NOT GET TOO SPECIFIC AT THIS TIME. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 632 AM EDT MON APR 2 2012 LOW CLOUDS AND SOME FOG WILL AFFECT CMX AND SAW THROUGH MID MORNING. MAIN IMPACT WILL BE CIGS BLO ALTERNATE AIRPORT MINS BUT BRIEF VSBY OF LIFR/IFR POSSIBLE AS WELL. PROBLEM AT IWD WILL BE SHRA/ISOLD TSRA THROUGH MID MORNING. COULD SEE BRIEF VSBY REDUCTIONS BUT SHOULD ONLY BE MVFR BASED ON UPSTREAM OBSERVATIONS AND SINCE SE WIND DIRECTION IS NOT FAVORABLE FOR ANY ADDITIONAL LIFTING VIA UPSLOPE. EXPECT ALL TAF SITES TO BE VFR BY EARLY AFTN WITH SCT-BKN MID CLOUDS. MAIN FRONT AND SFC LOW COME ACROSS UPR MICHIGAN TONIGHT. SCT LINE OF SHRA AND PERHAPS A TSRA AS WELL WILL SLIDE WEST-TO-EAST LATER IN THE EVENING THROUGH THE OVERNIGHT HOURS. MODELS VARY ON EXACT DEPICTION OF RAIN WITH FROPA SO KEPT WITH BROADBRUSHED DEPICTION FOR THE TIMING OF THE RAIN. POTENTIAL FOR SIGNIFICANT REDUCTION TO CIGS/VSBY WITH ANY SHOWERS DOES APPEAR REMOTE RIGHT NOW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 515 AM EDT MON APR 2 2012 WINDS SHOULD REMAIN BELOW 30KTS THROUGH AT LEAST FRIDAY. AN EXITING RIDGE OVER LAKE HURON WILL DRIFT ACROSS THE LOWER GREAT LAKES TODAY. IN ITS PLACE...A TROUGH WILL SLIDE IN FOR LATE TONIGHT INTO TUESDAY MORNING. EXPECT A HIGH OVER THE NORTHERN PLAINS AND CENTRAL CANADA TUESDAY TO SLOWLY SLIDE OVER LS WEDNESDAY...WHERE IT SHOULD REMAIN THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLA SHORT TERM...JLA LONG TERM...KF AVIATION...JLA MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
515 AM EDT MON APR 2 2012 .SYNOPSIS... ISSUED AT 515 AM EDT MON APR 2 2012 UPPER RIDGE BUILDS INTO THE AREA TODAY BUT MOISTURE ADVECTION AT H85/H7 IS ALREADY SPAWNING SHRA/TSRA FM NORTHERN MN INTO NW WI AND TOWARD FAR WESTERN UPR MI. WILL HAVE TO CONTEND WITH AT LEAST ISOLD SHRA/TSRA TODAY MAINLY OVR WEST THIRD OF CWA. BETTER CHANCE FOR RAIN ARRIVES LATER TONIGHT AS SFC LOW AND INVERTED TROUGH SLIDE ACROSS UPR MI. SOME RAIN LINGERS ON TUESDAY MORNING BUT AFTER THAT DRY WEATHER DOMINATES THE REST OF THE WEEK AS HIGH PRESSURE EXPANDS FM HUDSON BAY ACROSS THE GREAT LAKES REGION. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 515 AM EDT MON APR 2 2012 TODAY...UPPER RIDGE CONTINUES TO BUILD FM THE PLAINS INTO THE WESTERN GREAT LAKES THROUGH THE DAY WHILE AT THE SFC...HIGH OVR HUDSON BAY WILL EXPAND A RIDGE AXIS ACROSS MUCH OF MICHIGAN. AT FIRST GLANCE...DOES NOT APPEAR TO BE A FAVORABLE SETUP FOR MUCH PRECIPITATION TODAY OVR UPR MI...BUT CERTAINLY CANNOT IGNORE CLUSTER OF SHRA/TSRA THAT HAVE FORMED OVR NORTHERN MN INTO NORTHWEST WI THE LAST FEW HOURS. SHRA/TSRA SEEM TO BE RUNNING ALONG AND NORTH OF RIBBON OF HIGHER H7 DWPNTS AND ON NORTHERN EDGE OF STEEPER H7-H5 LAPSE RATES FM MN INTO WI. ONLY 00Z GUIDANCE THAT SHOWED TSRA AS FAR EAST AS IS CURRENTLY OCCURRING WAS HRRR. ALL OTHER GUIDANCE KEPT GENESIS REGION FOR SHRA/TSRA OVR WESTERN MN WHERE BETTER H85 THETA-E ADVECTION IS TAKING PLACE. FOLLOWING RUC13/NAM H7 DWPNTS/WINDS SUGGESTS THAT AT LEAST ISOLD TSRA WILL EASE INTO WESTERN THIRD OF CWA THIS MORNING BEFORE FADING AWAY AS RIBBON OF HIGHER H7 DWPNT WEAKENS. WILL KEEP POPS IN OVR WEST ALL DAY THOUGH AS RUC INDICATES HINT OF H7 MOISTURE AXIS COULD PERSIST INTO EARLY AFTN. DESPITE RESERVOIR OF H7-H5 LAPSE RATES AOA 8C/KM UPSTREAM...MINIMAL LARGE SCALE FORCING AND MARGINAL 3-6KM SHEAR /20KT OR SO/ SHOULD LEAD TO ONLY SLIM CHANCES OF SEEING HAIL WITH THESE STORMS. WILL NEED TO MONITOR TRENDS THIS MORNING THOUGH. BY LATE AFTN...EXPECT MAIN AREA OF SHRA/TSRA WEST OF UPR MI IN AREA OF GREATEST H85 TEMP/MOISTURE ADVECTION. OTHER ISSUE TODAY ESPECIALLY THIS MORNING IS FOG. FOR THE MOST PART THE FOG IS OVR HIGHER TERRAIN OF NCNTRL CWA AND HIGHER TERRAIN OF KEWEENAW. EVEN IN THESE AREAS MAIN IMPACT IS MORE OF STRATUS DECK WITH VARIABLE VSBY. EXPECT DRY ADVECTION OVR EASTERN UPR MI TO SPREAD EAST AND DIMINISH THE FOG BY MID MORNING /AS ALREADY HAS OCCURRED AT ERY EARLY THIS MORNING/. COVERAGE OF CLOUDS /LOWER AND MID/ BY MID AFTN COULD BE CHAOTIC WHICH WILL NO-DOUBT IMPACT HIGH TEMPS. SE GRADIENT WIND OFF THE LAKES SHOULD KEEP TEMPS IN CHECK EVEN IF DECENT AMOUNT OF SUNSHINE ENDS UP OCCURRING. EXPECT HIGHS TO MAINLY TOP OUT IN THE 50S...COOLER NCNTRL WITH UPSLOPE FLOW. GIVEN ENOUGH SUNSHINE SOME SPOTS MAY PUSH PAST 60 DEGREES...BUT NOT TOO MUCH HIGHER. TONIGHT...UPR RIDGE REMAINS IN TACT TO START THE EVENING THEN OVERNIGHT NORTHERN STREAM SHORTWAVE MOVES FM MANITOBA INTO NORTHWEST ONTARIO. AS THIS TROUGH APPROACHES...SFC LOW OVR THE PLAINS WILL LIFT INTO WESTERN GREAT LAKES WITH INVERTED SFC TROUGH AND H85 TROUGH SLIDING WEST TO EAST ACROSS UPR MI. MODELS HAVE TRENDED A BIT SLOWER WITH ARRIVAL OF UPR AND SFC TROUGH. PREVIOUS FCST HAD GOOD HANDLE ON TREND WITH HIGHER POPS OVERNIGHT. WHAT TO DO WITH POP COVERAGE IS MAIN ISSUE. BASED ON EXPECTED LARGE SCALE PATTERN AND FCST LOCATION OF HIGHER MUCAPE...WOULD FIGURE THAT HIGHEST POPS WOULD BE OVER LK SUPERIOR AND MAINLY TO SOUTH OF CWA. THOUGH CONVERGENCE FM INVERTED SFC TROUGH INTERSECTING S/SW FLOW AT H85 /DPWNTS AOA +10C/ SUPPORTS HIGHER POPS OVR CWA AS WELL. KEPT POPS HIGH CHANCE TO LIKELY AS THE INVERTED TROUGH SLIDES THROUGH CWA. TSRA CHANCES SEEM MINIMAL BASED ON MAIN MUCAPE STAYING OVR WI AND 850-300MB THICKNESSES ORIENTED WNW TO ESE. HOWEVER...IF CONVECTION MAINLY FIRES ON FAR NORTH EDGE OF HIGHER INSTABILITY /AS OCCURRED THIS MORNING/ THEN IT IS FEASIBLE THERE COULD BE COMPLEX OF TSRA AFFECTING PORTIONS OF CWA OVERNIGHT TONGIHT INTO EARLY TUESDAY MORNING. LIKELY WILL NOT KNOW IF THIS IS THE CASE UNTIL MAYBE LATE THIS EVENING OR OVERNIGHT TONIGHT. TUESDAY...SLOWER TREND OF TROUGH PASSAGE CONTINUES TO SHOW UP INTO TUESDAY AND HAVE DELAYED DIMINISHING POPS UNTIL EARLY TUESDAY AFTN. AT THIS POINT /COULD BE FURTHER SLOWER TREND/ HIGHEST POPS ON TUESDAY WILL BE THROUGH ROUGHLY 16Z /NOON EDT/ OVR EASTERN HALF OF CWA MAINLY TO EAST OF MARQUETTE AND IRON MOUNTAIN. KEPT SMALL CHANCES FOR TSRA IN PICTURE ALONG LK MICHIGAN IN THE MORNING UNTIL H85 WINDS VEER WEST PUSHING THE HIGHER H85 DWPNTS/INSTABILITY TO SOUTHEAST OF CWA. WINDS TURNING NORTH BEHIND THE TROUGH SHOULD KEEP CLOUDS IN OVR MUCH CWA THROUGH MUCH OF AFTN. DECREASING CLOUDS EXPECTED LATE AFTN THOUGH PER MODEL CONSENSUS OF RAPIDLY LOWERING DWPNTS AT H85 AND PER FCST SOUNDINGS. POSSIBLE THAT SOME LOW CLOUDS AND/OR FOG MAY TRY TO ADVECT ONSHORE SIMILAR TO WHAT OCCURRED SUNDAY AFTN. LATER SHIFTS CAN ADDRESS THIS IN MORE DETAIL AND ADD IF IT SEEMS REASONABLE. LOWERED TEMPS ESPECIALLY IN THE NORTH CWA DUE TO LATER DEPARTURE OF PCPN AND CLOUDS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 515 AM EDT MON APR 2 2012 HIGH PRESSURE SLIDING IN TUESDAY EVENING FROM MANITOBA AND EASTERN ND/WESTERN MN WILL BRING ABOUT A PROLONGED PERIOD OF DRY WEATHER. EXPECT THE HIGH TO PUSH OVER THE UPPER GREAT LAKES WEDNESDAY AFTERNOON...BEFORE STRENGTHENING ACROSS THE AREA THROUGH FRIDAY. GIVEN A SLIGHTLY SLOWER SOLUTION AND A LINGERING 500MB TROUGH OVERHEAD THROUGH WEDNESDAY EVENING...WILL KEEP WITH LINGERING CLOUDS EAST INITIALLY TUESDAY NIGHT...AND AFTERNOON CLOUDS DEVELOPING NEAR 900MB POSSIBLE CENTRAL AND EAST. EXPECT ONLY LIMITED CLOUDS AT THIS TIME GIVEN OUR DRY ATMOSPHERE WITH PW VALUES ABOUT 60 PERCENT OF NORMAL AROUND 0.26IN. LOWERED DEW POINTS A COUPLE OF DEGREES FOR WEDNESDAY AFTERNOON...MAINLY INTERIOR WEST...WITH RH VALUES ACROSS THIS AREA BOTTOMING OUT AROUND 25 TO 30 PERCENT. WITH NO SIGNIFICANT INFLUX OF MOISTURE...RH VALUES SHOULD FALL BETWEEN 25 AND 35 PERCENT THROUGH FRIDAY /ONCE AGAIN MAINLY ACROSS THE INTERIOR WEST HALF/. LOW PRESSURE DEVELOPING OFF THE NORTHERN ROCKIES MID WEEK SHOULD PUSH ACROSS THE PLAINS STATES FRIDAY NIGHT...BEFORE SLIDING DEEPENING TO OUR WEST SATURDAY...AND PUSHING UP AND ACROSS ONTARIO SATURDAY NIGHT INTO SUNDAY. THE FORECAST MODELS LOOK TO BE IN FAIRLY GOOD AGREEMENT UNTIL THE FOCUS SHIFTS TO THE NEARING LOW SATURDAY AFTERNOON. AFTER SATURDAY...I HAVE ONLY MODERATE CONFIDENCE IN THE ONGOING FORECAST /MAINLY WITH RESPECT TO TIMING AND PRECIPITATION TYPE AS THE LOW EXITS/. AFTERNOON TS SATURDAY MAY LINGER INTO SATURDAY NIGHT EAST. WHILE THE QUICKER 01/12Z RUN OF THE ECMWF WOULD HAVE THEM OUT OF ERY BY 06Z SUNDAY. WILL TAKE OUT ANY MENTION OF WRAP AROUND SHSN SUNDAY...BUT IT MAY NEED TO BE ADDED BACK IN IF THE ECMWF VERIFIES WITH 850MB TEMPS FALLING TO AROUND -3 OR -4C BY EARLY AFTERNOON WEST AND CENTRAL. INSTEAD OF RUNNING A NON-DIURNAL TEMP TRACE FOR SUNDAY...KEPT WITH TRADITIONAL RISING TEMPS DURING THE DAY /SIMILAR TO THE GFS/. AS NOTED...THIS WILL LIKELY BE REVISED MORE THAN A FEW TIMES BEFORE OVER THE NEXT FEW DAYS AS FCST MODELS MERGE ON A SOLUTION...SO WILL NOT GET TOO SPECIFIC AT THIS TIME. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 147 AM EDT MON APR 2 2012 ALTHOUGH DRIER AIR IS ADVECTING THRU UPR MI IN THE STEADY E WIND ON THE SRN FLANK OF HI PRES IN ONTARIO...LINGERING POCKETS OF LO CLDS OVER ERN UPR MI WARRANT HOLDING ON TO A MENTION OF AT LEAST TEMPO IFR CIGS THRU SUNRISE AT CMX/SAW...WHERE THE WIND WL HAVE AN UPSLOPE COMPONENT. WITH A DOWNSLOPE COMPONENT AT IWD...EXPECT ANY LO CLD TO BREAK UP BEFORE REACHING THAT SITE. WILL HAVE TO WATCH FOR POSSIBLE ISOLD THUNDERSTORMS CURRENTLY NEAR DLH REACHING INTO IWD BTWN NOW AND DAYBREAK. WITH THE ONSET OF DAYTIME HEATING...VFR CONDITIONS SHOULD PREVAIL AFTER ANY LINGERING LO CLDS DISAPPEAR SOON AFTER SUNRISE. SOME SHRA IN ADVANCE OF A LO PRES TROF APPROACHING FM THE W MAY IMPACT IWD/CMX LATE THIS AFTN INTO THIS EVNG...BUT LINGERING DRY AIR IN THE LLVLS INDICATE VFR CONDITIONS SHOULD PERSIST THRU 06Z. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 515 AM EDT MON APR 2 2012 WINDS SHOULD REMAIN BELOW 30KTS THROUGH AT LEAST FRIDAY. AN EXITING RIDGE OVER LAKE HURON WILL DRIFT ACROSS THE LOWER GREAT LAKES TODAY. IN ITS PLACE...A TROUGH WILL SLIDE IN FOR LATE TONIGHT INTO TUESDAY MORNING. EXPECT A HIGH OVER THE NORTHERN PLAINS AND CENTRAL CANADA TUESDAY TO SLOWLY SLIDE OVER LS WEDNESDAY...WHERE IT SHOULD REMAIN THROUGH FRIDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLA SHORT TERM...JLA LONG TERM...KF AVIATION...KC/JLA MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
330 PM CDT MON APR 2 2012 .DISCUSSION... SEVERE WEATHER THREAT REMAINS MAIN FOCUS FOR THE EVENING. LATEST AVAILABLE RUC INDICATING WARM SECTOR TO WORK INTO SOUTH CENTRAL MINNESOTA THIS EVENING. MLCIN DROP OFF MARKEDLY AS WELL...BUT BELIEVE CAP WILL HOLD FOR ANY REAL SURFACE BASED CONVECTION. SHOULD SEE ELEVATED ACTIVITY INITIATE OVER SOUTHWEST MINNESOTA NEAR REDWOOD FALLS...AND THEN MOVE EAST DURING THE EVENING...AFFECTING SOUTH CENTRAL MINNESOTA. MOST ALL DETERMINISTIC RUNS INDICATE THIS AS WELL. VERY STEEP/UNSTABLE MID LEVEL LAPSE RATES IN EXCESS OF 8C/KM WITH ELEVATED CAPE AROUND 1200 J/KG MOVING...SHOULD BE ENOUGH TO GENERATE THE CONVECTION. HAIL WILL BE THE MAIN THREAT WITH SOME WIND POSSIBLE AS WELL. UPPER TROUGH MOVES ACROSS THE CWA OVERNIGHT...AND IS SLOWER THAN WHAT MODELS WERE SHOWING YESTERDAY. WILL HAVE TO LINGER SOME SLIGHT CHANCE POPS OVER THE SOUTHERN CWA INTO TUESDAY MORNING... WITH CLEARING EXPECTED THEREAFTER. COOLER TEMPERATURES EXPECTED THEN FOR THE NEXT SEVERAL DAYS...BUT STILL RANGING ABOVE NORMAL. NORTHERLY WINDS WILL INCREASE TONIGHT BEHIND DEPARTING SYSTEM AND WILL REMAIN BREEZY INTO TUESDAY AS THE COLDER AIR MOVES IN. WINDS WILL DIMINISH TUESDAY EVENING AND WITH LARGE HIGH PRESSURE DROPPING SOUTH OVER THE AREA...WILL LIKELY SEE SOME FROST DEVELOP INTO WEDNESDAY MORNING. PREVIOUS FORECAST HAD THIS MENTIONED AND STILL LOOKS GOOD. THERE WILL BE ANOTHER OPPORTUNITY FOR FROST...MAINLY OVER WEST CENTRAL WISCONSIN WEDNESDAY NIGHT/THURSDAY MORNING AS THE HIGH RETREATS TO THE EAST. LONG RANGE MODELS CONTINUE TO TREND ANOTHER WAVE ACROSS THE AREA LATER FRIDAY NIGHT INTO SATURDAY SATURDAY NIGHT TIME FRAME. EVEN COLDER AIR TO FOLLOW THIS FRONT...POSSIBLE MAKING TEMPERATURES CLOSER TO NORMAL FOR THIS TIME OF THE YEAR. && .AVIATION.../18Z TAF ISSUANCE/ SFC LOW PRESSURE OVER SE SD WILL SHIFT ENE OVER SRN MN INTO WRN WI THROUGH TONIGHT...DRAGGING A CDFNT WITH IT. LOW CLOUDS ARE CONTINUING TO ERODE OVER SW AND W MN WHILE CENTRAL AND ERN MN INTO WRN WI ARE DEALING WITH SCT COVERAGE OF HIGHER CLOUDS. GUSTY SE WINDS WILL PERSIST THROUGH THIS EVENING THEN SETTLE DOWN A BIT OVERNIGHT...BUT NOT EXPECTING MUCH BELOW 10 KT. AS THE SFC LOW SHIFTS E...CHCS INCREASE FOR SHWRS WITH A FEW ISOLD TSTMS. BETTER PROSPECTS FOR THUNDER OVER NRN MN AND IA...BUT ISOLD TS CANNOT BE RULED OUT FOR ANY OF THE TAF SITES. THAT SAID...EVEN THE SHORT- TERM MODELS ARE SHOWING DIFFERING SCENARIOS AS TO THE LOCATION/TIMING OF THUNDER. HAVE TWEAKED THE TIMING OF THE TEMPO GROUPS AT EACH SITE TO REFLECT BEST TIMING OF PRECIP BUT HAVE ONLY USED MENTION OF CB TO INDICATE CONVECTION. FELT THIS WAS THE BETTER WAY TO GO RATHER THAN TRYING TO PIN DOWN TS WITH LOW CONFIDENCE. ONCE THE PRECIP CEASES DURING THE EARLY MRNG HOURS... MVFR CIGS WILL LINGER THROUGH DAYBREAK. INCREASED LOW LEVEL JETTING WILL PREVENT CIGS FROM GETTING DOWN TO IFR LEVELS OR HAVING ANY SIGNIFICANT FOG DEVELOPING...BUT THERE SHOULD BE SOME PERIODS OF MVFR VSBYS AFTER THE RAIN ENDS. AS THE LOW SHIFTS E AND HIGH PRESSURE SLOWLY ENTERS FROM THE NW TMRW...CLOUDS WILL LIFT AND SCATTER OUT...LEADING TO VFR CONDS BY MIDDAY TMRW. WINDS WILL ALSO INCREASE AND BECOME GUSTY AGAIN AS THE PRESSURE GRADIENT TIGHTENS WITH THE INCOMING HIGH PRESSURE. MSP...VFR CONDS EXPECTED TO PREVAIL THROUGH THIS EVENING THOUGH THERE MAY BE SOME BOUNCING BETWEEN SCT AND BKN COVERAGE WITH BASES ARND 4000 FT. COVERAGE BECOMES DECIDEDLY BKN LATE THIS EVE AS THE FRONTAL SYSTEM APPROACHES. BEST TIMING FOR PRECIP ONSET LOOKS TO BE AROUND 06Z THEN CONTINUING TO SHORTLY BEFORE DAYBREAK. AM NOT LOOKING FOR A PROLONGED DURATION OF PRECIP SINCE THIS IS MORE OF A CONVECTIVELY-BASED EVENT RATHER THAN STRATIFORM...BUT ALTHOUGH MSP TAF ADVERTISES NO PRECIP AFTER 10Z...SOME SHOWERS GOING INTO SUNRISE CANNOT BE RULED OUT. THUNDER CHCS ARE RATHER LOW BUT WITH ISOLD TSTMS POSSIBLE...CB MENTION LOOKS TO COVER THINGS. CONDITIONS IMPROVE LATE MRNG INTO THE EARLY AFTN HOURS...BECOMING VFR BY EARLY AFTN. GUSTY CONDITIONS THIS AFTN SETTLE DOWN A BIT OVERNIGHT THEN RETURN TMRW WITH THE INCOMING HIGH PRESSURE. OUTLOOK... /TUE NIGHT-FRI/...VFR AS HIGH PRESSURE MOVES ACROSS. /SAT-SUN/...POSSIBLE FRONTAL SYSTEM MOVES OVER THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI RIVER VALLEY. MVFR CONDS POSSIBLE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ DWE/JPC
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1244 PM CDT MON APR 2 2012 .AVIATION...04/02/18Z ISSUANCE... VFR IN BROKEN CLOUDS...WITH AREAS OF SCATTERED CLOUDS ACROSS NORTHWEST WISCONSIN. ISOLATED INTENSE THUNDERSTORMS WITH HAIL... JUST SOUTH OF INL...SHOULD SLOWLY WEAKEN AND PASS NORTHEAST INTO CANADA NEAR RAINY LAKE LATE THIS AFTERNOON. SCATTERED MVFR IN SHOWERS AND A FEW THUNDERSTORMS WILL DEVELOP OVER OUR AREA...WEST OF A CENTRAL LAKE SUPERIOR TROUGH...THIS EVENING. VFR AND CLEARING WILL SPREAD TOWARD THE SOUTHEAST BEGINNING IN NORTHEAST MINNESOTA EARLY TUESDAY AND CONTINUING THROUGH NORTHWEST WISCONSIN AROUND MIDDAY TUESDAY. && .PREV DISCUSSION... /ISSUED 1027 AM CDT MON APR 2 2012/ UPDATE... THE 12Z NAM AND 09Z SREF ARE REASONABLE IN THE PLACEMENT OF THE CURRENT BAND OF ELEVATED THUNDERSTORMS STRETCHING FROM NEAR BIG FORK TO CRANE LAKE IN THE NORTHWESTERN FA. THEREFORE...MADE UPDATES TO POPS/WEATHER THROUGH THIS AFTERNOON THAT LEANED ON THE NAM/SREF WHICH FOCUSES PCPN ACROSS THE NORTHERN AND WESTERN FA. DOWNPLAYED THE EMPHASIS ON THE CHANCES OF THUNDER TO GIVE GREATER EMPHASIS ON RAIN SHOWERS SINCE MODEL INDICES AND INSTABILITY DO NOT APPEAR FAVORABLE FOR CONVECTION. AT THIS TIME...THE SPC MESOANALYSIS PAGE INDICATES UP TO 5OO J/KG OF ELEVATED CAPE BY THAT BAND OF THUNDERSTORMS...AND MOST UNSTABLE LIFTED INDICES AROUND -2 TO -5. THERE HAVE BEEN SOME REPORTS OF MINOR HAIL WITH THESE STORMS...AND THIS TREND OF PULSING STORMS WITH SMALL HAIL WILL LIKELY CONTINUE FOR AT LEAST THE NEAR FUTURE. WHILE THE UPDATES PULLED SOME EMPHASIS OF PCPN FROM THE SOUTHERN FA...WILL NEED TO KEEP AN EYE ON A BOUNDARY STRETCHING FROM ABOUT HINCKLEY TO NORTHERN CASS COUNTY THAT IS MOVING TO THE SOUTHWEST. SINCE THERE IS GREATER INSTABILITY ACROSS THE SOUTHWESTERN FA...WILL NEED TO SEE IF THIS BOUNDARY BECOMES A TRIGGER FOR STORMS. ONLY MADE MINOR CHANGES TO THE TEMPERATURES AND WINDS. PREV DISCUSSION... /ISSUED 331 AM CDT MON APR 2 2012/ SHORT TERM...RUC ANALYSIS DOING GOOD JOB HIGHLIGHTING GENESIS REGION OF CONVECTION THIS MORNING OVER WCTRL MN. MID LVL INSTABILITY AXIS IS ALIGNED EAST ACROSS CWA FROM CASS LAKE TO TWIN PORTS AND THEN SE TO NRN PRICE COUNTY. CONVECTION HAS TRAINED ALONG THIS CORRIDOR WITH SMALL HAIL REPORTED AT TIMES. A SECONDARY 70H THETAE MAX IS DEVELOPING ACROSS SRN KOOCH/NRN ITASCA VICINITY AND NEW CONVECTION IS FORMING THERE AS WELL. AREA REMAINS UNDER MID LVL RIDGE AXIS WITH A WEAK SHORTWAVE TROF LIFTING OVER RIDGE AXIS. TODAY...USED RUC AS SHORT TERM GUIDANCE FOR PLACING HIGHER POPS ALONG AFOREMENTIONED INSTABILITY AXIS AS IT MOVES GRADUALLY NORTH THIS MORNING. BY MIDDAY FOCUS OF CONVECTION MAY BE ALIGNED FROM NWRN CWA TO NR ST LOUIS COUNTY AND THEN SE TO ERN WISC ZONES. SMALL HAIL STILL POSSIBLE WITH SOME STORMS. AT THAT TIME... 85H MSTR TRANSPORT AXIS IS FCST TO STRETCH FROM ST CROIX VALLEY TO KOOCH COUNTY. WARM ADVECTION AT MID LVLS WILL TEND TO INHIBIT MOST OF THE ACTIVITY ACROSS THE SRN CWA BY 18Z. WE SHOULD SEE A WELL DEVELOPED BAND OF RAIN/THUNDERSTORMS FROM SE NDAK INTO NWRN MN. THIS WILL BE OCCURRING ON NWRN SIDE OF SFC LOW IN AN AREA OF DIVERGENCE ALOFT SUPPLIED BY RIGHT ENTRANCE REGION OF UPPER JET.THIS CORRIDOR OF DEEP LAYER LIFT WILL TEND TO REMAIN OVER THE SAME REGION THROUGH THE AFTERNOON. SIGNIFICANT RAINFALL MAY OCCUR AND WE WILL NEED TO WATCH KOOCH/NWRN ITASCA COUNTY AREA FOR ADDITIONAL UPDATES. TONIGHT/TOMORROW...NRN BRANCH OF WESTERLIES WILL ADVANCE ACROSS CWA OVERNIGHT. THIS WILL PUSH FRNTL SYSTEM THROUGH AS SFC HIGH BUILDS INTO CWA FROM NRN PLAINS. DEEP LAYER DRYING REFLECTED IN INTEGRATED RH PRODUCTS AND MDL XSECTS. SHOULD SEE MOSTLY SUNNY SKIES ADVANCING ACROSS CWA AS DAY UNFOLDS. WITH INCREASED MIXING DURING DAY...UNIDIRECTIONAL FLOW IN LOWEST 5K FT....SHOULD SEE SOME GUSTY WINDS DEVELOPING. SFC DEWPOINTS MAY NEED LOWERING AS MIX DOWN OF DRIER AIR OCCURS IN AFTN. EXTENDED...TUESDAY NIGHT THROUGH SUNDAY... UPPER LEVEL AND SFC RIDGING WILL COVER THE FA TUESDAY NIGHT THROUGH FRIDAY. THE RIDGING MOVES JUST E OF THE AREA FRIDAY AFTERNOON ALLOWING FOR A SOUTHERLY WAA/RETURN FLOW PATTERN TO BECOME ESTABLISHED. A SHORT WAVE TROF WILL MOVE FROM THE NORTHERN PLAINS FRIDAY NIGHT INTO THE GREAT LAKES SATURDAY NIGHT. IN THE MEANTIME...AN ASSOCIATED SFC LOW MOVING THROUGH SOUTHERN CANADA WILL PUSH A COLD FRONT THROUGH THE FA AND EXIT SATURDAY NIGHT. THIS COMBINATION WARRANTS SOME POPS FRIDAY NIGHT THROUGH SUNDAY. BEST INSTABILITY WILL BE FOUND OVER THE SOUTHERN THIRD OF THE AREA SATURDAY AND HAVE A MENTION OF THUNDERSTORMS. && .POINT TEMPS/POPS... DLH 52 40 58 35 / 30 60 10 0 INL 52 36 58 30 / 60 60 10 0 BRD 63 41 61 34 / 40 60 10 0 HYR 63 42 61 33 / 10 60 20 0 ASX 58 41 57 34 / 30 60 20 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121- 140>148. && $$ SHORT TERM...GROCHOCINSKI LONG TERM....EOM AVIATION...EOM
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1027 AM CDT MON APR 2 2012 .UPDATE... THE 12Z NAM AND 09Z SREF ARE REASONABLE IN THE PLACEMENT OF THE CURRENT BAND OF ELEVATED THUNDERSTORMS STRETCHING FROM NEAR BIG FORK TO CRANE LAKE IN THE NORTHWESTERN FA. THEREFORE...MADE UPDATES TO POPS/WEATHER THROUGH THIS AFTERNOON THAT LEANED ON THE NAM/SREF WHICH FOCUSES PCPN ACROSS THE NORTHERN AND WESTERN FA. DOWNPLAYED THE EMPHASIS ON THE CHANCES OF THUNDER TO GIVE GREATER EMPHASIS ON RAIN SHOWERS SINCE MODEL INDICES AND INSTABILITY DO NOT APPEAR FAVORABLE FOR CONVECTION. AT THIS TIME...THE SPC MESOANALYSIS PAGE INDICATES UP TO 5OO J/KG OF ELEVATED CAPE BY THAT BAND OF THUNDERSTORMS...AND MOST UNSTABLE LIFTED INDICES AROUND -2 TO -5. THERE HAVE BEEN SOME REPORTS OF MINOR HAIL WITH THESE STORMS...AND THIS TREND OF PULSING STORMS WITH SMALL HAIL WILL LIKELY CONTINUE FOR AT LEAST THE NEAR FUTURE. WHILE THE UPDATES PULLED SOME EMPHASIS OF PCPN FROM THE SOUTHERN FA...WILL NEED TO KEEP AN EYE ON A BOUNDARY STRETCHING FROM ABOUT HINCKLEY TO NORTHERN CASS COUNTY THAT IS MOVING TO THE SOUTHWEST. SINCE THERE IS GREATER INSTABILITY ACROSS THE SOUTHWESTERN FA...WILL NEED TO SEE IF THIS BOUNDARY BECOMES A TRIGGER FOR STORMS. ONLY MADE MINOR CHANGES TO THE TEMPERATURES AND WINDS. && .PREV DISCUSSION... /ISSUED 641 AM CDT MON APR 2 2012/ AVIATION...12Z TAFS. BKN MID DECK DEVELOPING OVER NE MN AND NW WI WILL AFFECT THE TAF SITES THROUGH THIS FORECAST CYCLE. SHOWERS FROM THE MN ARROWHEAD INTO NW WI TO MOVE E AND DISSIPATE. SFC TROF IN THE RED RIVER VALLEY WILL MOVE INTO THE FA ALONG WITH MID LEVEL INSTABILITY AXIS. SOME SHOWERS MAY FORM BY 15Z NEAR KINL...HOLDING OFF UNTIL LATER THIS AFTERNOON NEAR KHIB/KBRD. INSTABILITY AXIS ALIGNS ITSELF OVER THE AREA BETWEEN 18Z-21Z AND ALONG WITH THE SFC TROF WILL BE THE FOCUS FOR THUNDERSTORMS. USED VCTS AT KBRD/KHYR AS TIMING OF STORMS IS IN QUESTION AND CONFIDENCE IS LOW. PCPN WILL DIMINISH FROM NW TO SE THIS EVENING WITH LOSS OF SOLAR/INSTABILITY. PREV DISCUSSION... /ISSUED 331 AM CDT MON APR 2 2012/ SHORT TERM...RUC ANALYSIS DOING GOOD JOB HIGHLIGHTING GENESIS REGION OF CONVECTION THIS MORNING OVER WCTRL MN. MID LVL INSTABILITY AXIS IS ALIGNED EAST ACROSS CWA FROM CASS LAKE TO TWIN PORTS AND THEN SE TO NRN PRICE COUNTY. CONVECTION HAS TRAINED ALONG THIS CORRIDOR WITH SMALL HAIL REPORTED AT TIMES. A SECONDARY 70H THETAE MAX IS DEVELOPING ACROSS SRN KOOCH/NRN ITASCA VICINITY AND NEW CONVECTION IS FORMING THERE AS WELL. AREA REMAINS UNDER MID LVL RIDGE AXIS WITH A WEAK SHORTWAVE TROF LIFTING OVER RIDGE AXIS. TODAY...USED RUC AS SHORT TERM GUIDANCE FOR PLACING HIGHER POPS ALONG AFOREMENTIONED INSTABILITY AXIS AS IT MOVES GRADUALLY NORTH THIS MORNING. BY MIDDAY FOCUS OF CONVECTION MAY BE ALIGNED FROM NWRN CWA TO NR ST LOUIS COUNTY AND THEN SE TO ERN WISC ZONES. SMALL HAIL STILL POSSIBLE WITH SOME STORMS. AT THAT TIME... 85H MSTR TRANSPORT AXIS IS FCST TO STRETCH FROM ST CROIX VALLEY TO KOOCH COUNTY. WARM ADVECTION AT MID LVLS WILL TEND TO INHIBIT MOST OF THE ACTIVITY ACROSS THE SRN CWA BY 18Z. WE SHOULD SEE A WELL DEVELOPED BAND OF RAIN/THUNDERSTORMS FROM SE NDAK INTO NWRN MN. THIS WILL BE OCCURRING ON NWRN SIDE OF SFC LOW IN AN AREA OF DIVERGENCE ALOFT SUPPLIED BY RIGHT ENTRANCE REGION OF UPPER JET.THIS CORRIDOR OF DEEP LAYER LIFT WILL TEND TO REMAIN OVER THE SAME REGION THROUGH THE AFTERNOON. SIGNIFICANT RAINFALL MAY OCCUR AND WE WILL NEED TO WATCH KOOCH/NWRN ITASCA COUNTY AREA FOR ADDITIONAL UPDATES. TONIGHT/TOMORROW...NRN BRANCH OF WESTERLIES WILL ADVANCE ACROSS CWA OVERNIGHT. THIS WILL PUSH FRNTL SYSTEM THROUGH AS SFC HIGH BUILDS INTO CWA FROM NRN PLAINS. DEEP LAYER DRYING REFLECTED IN INTEGRATED RH PRODUCTS AND MDL XSECTS. SHOULD SEE MOSTLY SUNNY SKIES ADVANCING ACROSS CWA AS DAY UNFOLDS. WITH INCREASED MIXING DURING DAY...UNIDIRECTIONAL FLOW IN LOWEST 5K FT....SHOULD SEE SOME GUSTY WINDS DEVELOPING. SFC DEWPOINTS MAY NEED LOWERING AS MIX DOWN OF DRIER AIR OCCURS IN AFTN. EXTENDED...TUESDAY NIGHT THROUGH SUNDAY... UPPER LEVEL AND SFC RIDGING WILL COVER THE FA TUESDAY NIGHT THROUGH FRIDAY. THE RIDGING MOVES JUST E OF THE AREA FRIDAY AFTERNOON ALLOWING FOR A SOUTHERLY WAA/RETURN FLOW PATTERN TO BECOME ESTABLISHED. A SHORT WAVE TROF WILL MOVE FROM THE NORTHERN PLAINS FRIDAY NIGHT INTO THE GREAT LAKES SATURDAY NIGHT. IN THE MEANTIME...AN ASSOCIATED SFC LOW MOVING THROUGH SOUTHERN CANADA WILL PUSH A COLD FRONT THROUGH THE FA AND EXIT SATURDAY NIGHT. THIS COMBINATION WARRANTS SOME POPS FRIDAY NIGHT THROUGH SUNDAY. BEST INSTABILITY WILL BE FOUND OVER THE SOUTHERN THIRD OF THE AREA SATURDAY AND HAVE A MENTION OF THUNDERSTORMS. && .POINT TEMPS/POPS... DLH 52 40 58 35 / 30 60 10 0 INL 52 36 58 30 / 60 60 10 0 BRD 63 41 61 34 / 40 60 10 0 HYR 63 42 61 33 / 10 60 20 0 ASX 58 41 57 34 / 30 60 20 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121- 140>148. && $$ SHORT TERM...GROCHOCINSKI LONG TERM....EOM
AREA FORECAST DISCUSSION
NWS DULUTH MN
641 AM CDT MON APR 2 2012 .AVIATION...12Z TAFS. BKN MID DECK DEVELOPING OVER NE MN AND NW WI WILL AFFECT THE TAF SITES THROUGH THIS FORECAST CYCLE. SHOWERS FROM THE MN ARROWHEAD INTO NW WI TO MOVE E AND DISSIPATE. SFC TROF IN THE RED RIVER VALLEY WILL MOVE INTO THE FA ALONG WITH MID LEVEL INSTABILITY AXIS. SOME SHOWERS MAY FORM BY 15Z NEAR KINL...HOLDING OFF UNTIL LATER THIS AFTERNOON NEAR KHIB/KBRD. INSTABILITY AXIS ALIGNS ITSELF OVER THE AREA BETWEEN 18Z-21Z AND ALONG WITH THE SFC TROF WILL BE THE FOCUS FOR THUNDERSTORMS. USED VCTS AT KBRD/KHYR AS TIMING OF STORMS IS IN QUESTION AND CONFIDENCE IS LOW. PCPN WILL DIMINISH FROM NW TO SE THIS EVENING WITH LOSS OF SOLAR/INSTABILITY. && .PREV DISCUSSION... /ISSUED 331 AM CDT MON APR 2 2012/ SHORT TERM...RUC ANALYSIS DOING GOOD JOB HIGHLIGHTING GENESIS REGION OF CONVECTION THIS MORNING OVER WCTRL MN. MID LVL INSTABILITY AXIS IS ALIGNED EAST ACROSS CWA FROM CASS LAKE TO TWIN PORTS AND THEN SE TO NRN PRICE COUNTY. CONVECTION HAS TRAINED ALONG THIS CORRIDOR WITH SMALL HAIL REPORTED AT TIMES. A SECONDARY 70H THETAE MAX IS DEVELOPING ACROSS SRN KOOCH/NRN ITASCA VICINITY AND NEW CONVECTION IS FORMING THERE AS WELL. AREA REMAINS UNDER MID LVL RIDGE AXIS WITH A WEAK SHORTWAVE TROF LIFTING OVER RIDGE AXIS. TODAY...USED RUC AS SHORT TERM GUIDANCE FOR PLACING HIGHER POPS ALONG AFOREMENTIONED INSTABILITY AXIS AS IT MOVES GRADUALLY NORTH THIS MORNING. BY MIDDAY FOCUS OF CONVECTION MAY BE ALIGNED FROM NWRN CWA TO NR ST LOUIS COUNTY AND THEN SE TO ERN WISC ZONES. SMALL HAIL STILL POSSIBLE WITH SOME STORMS. AT THAT TIME... 85H MSTR TRANSPORT AXIS IS FCST TO STRETCH FROM ST CROIX VALLEY TO KOOCH COUNTY. WARM ADVECTION AT MID LVLS WILL TEND TO INHIBIT MOST OF THE ACTIVITY ACROSS THE SRN CWA BY 18Z. WE SHOULD SEE A WELL DEVELOPED BAND OF RAIN/THUNDERSTORMS FROM SE NDAK INTO NWRN MN. THIS WILL BE OCCURRING ON NWRN SIDE OF SFC LOW IN AN AREA OF DIVERGENCE ALOFT SUPPLIED BY RIGHT ENTRANCE REGION OF UPPER JET.THIS CORRIDOR OF DEEP LAYER LIFT WILL TEND TO REMAIN OVER THE SAME REGION THROUGH THE AFTERNOON. SIGNIFICANT RAINFALL MAY OCCUR AND WE WILL NEED TO WATCH KOOCH/NWRN ITASCA COUNTY AREA FOR ADDITIONAL UPDATES. TONIGHT/TOMORROW...NRN BRANCH OF WESTERLIES WILL ADVANCE ACROSS CWA OVERNIGHT. THIS WILL PUSH FRNTL SYSTEM THROUGH AS SFC HIGH BUILDS INTO CWA FROM NRN PLAINS. DEEP LAYER DRYING REFLECTED IN INTEGRATED RH PRODUCTS AND MDL XSECTS. SHOULD SEE MOSTLY SUNNY SKIES ADVANCING ACROSS CWA AS DAY UNFOLDS. WITH INCREASED MIXING DURING DAY...UNIDIRECTIONAL FLOW IN LOWEST 5K FT....SHOULD SEE SOME GUSTY WINDS DEVELOPING. SFC DEWPOINTS MAY NEED LOWERING AS MIX DOWN OF DRIER AIR OCCURS IN AFTN. EXTENDED...TUESDAY NIGHT THROUGH SUNDAY... UPPER LEVEL AND SFC RIDGING WILL COVER THE FA TUESDAY NIGHT THROUGH FRIDAY. THE RIDGING MOVES JUST E OF THE AREA FRIDAY AFTERNOON ALLOWING FOR A SOUTHERLY WAA/RETURN FLOW PATTERN TO BECOME ESTABLISHED. A SHORT WAVE TROF WILL MOVE FROM THE NORTHERN PLAINS FRIDAY NIGHT INTO THE GREAT LAKES SATURDAY NIGHT. IN THE MEANTIME...AN ASSOCIATED SFC LOW MOVING THROUGH SOUTHERN CANADA WILL PUSH A COLD FRONT THROUGH THE FA AND EXIT SATURDAY NIGHT. THIS COMBINATION WARRANTS SOME POPS FRIDAY NIGHT THROUGH SUNDAY. BEST INSTABILITY WILL BE FOUND OVER THE SOUTHERN THIRD OF THE AREA SATURDAY AND HAVE A MENTION OF THUNDERSTORMS. AVIATION...06Z TAFS IFR/MVFR CEILINGS WILL OCCUR IN SPOTS THROUGH THE PERIOD...MOST LIKELY AROUND LAKE SUPERIOR. SOME FOG WILL ALSO BE POSSIBLE...ALTHOUGH SB`S HAVE INCREASED IN MOST AREAS DUE TO STRONG HIGH BUILDING SOUTH THROUGH ONTARIO. SHOWERS/STORMS WERE DEVELOPING JUST WEST OF KDLH...ON WEST TO NEAR KDTL. PERSISTENT WAA/MOISTURE TRANSPORT SHOULD LEAD TO ADDITIONAL SHOWER/STORM DEVELOPMENT OVERNIGHT INTO MONDAY. MVFR OR EVEN SOME IFR CONDITIONS WILL BE POSSIBLE WITH ANY SHOWERS/STORMS. STORMS SHOULD OCCUR MAINLY OVER NORTHEAST/NORTHERN MINNESOTA THROUGH MUCH OF MONDAY...TRANSLATING EAST MONDAY NIGHT. && .POINT TEMPS/POPS... DLH 52 40 58 35 / 40 60 10 0 INL 51 36 58 30 / 60 60 10 0 BRD 63 41 61 34 / 40 60 10 0 HYR 62 42 61 33 / 20 60 20 0 ASX 57 41 57 34 / 50 60 20 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121- 140>148. && $$ SHORT TERM...CANNON AVIATION...GSF
AREA FORECAST DISCUSSION
NWS DULUTH MN
331 AM CDT MON APR 2 2012 .SHORT TERM...RUC ANALYSIS DOING GOOD JOB HIGHLIGHTING GENESIS REGION OF CONVECTION THIS MORNING OVER WCTRL MN. MID LVL INSTABILITY AXIS IS ALIGNED EAST ACROSS CWA FROM CASS LAKE TO TWIN PORTS AND THEN SE TO NRN PRICE COUNTY. CONVECTION HAS TRAINED ALONG THIS CORRIDOR WITH SMALL HAIL REPORTED AT TIMES. A SECONDARY 70H THETAE MAX IS DEVELOPING ACROSS SRN KOOCH/NRN ITASCA VICINITY AND NEW CONVECTION IS FORMING THERE AS WELL. AREA REMAINS UNDER MID LVL RIDGE AXIS WITH A WEAK SHORTWAVE TROF LIFTING OVER RIDGE AXIS. TODAY...USED RUC AS SHORT TERM GUIDANCE FOR PLACING HIGHER POPS ALONG AFOREMENTIONED INSTABILITY AXIS AS IT MOVES GRADUALLY NORTH THIS MORNING. BY MIDDAY FOCUS OF CONVECTION MAY BE ALIGNED FROM NWRN CWA TO NR ST LOUIS COUNTY AND THEN SE TO ERN WISC ZONES. SMALL HAIL STILL POSSIBLE WITH SOME STORMS. AT THAT TIME... 85H MSTR TRANSPORT AXIS IS FCST TO STRETCH FROM ST CROIX VALLEY TO KOOCH COUNTY. WARM ADVECTION AT MID LVLS WILL TEND TO INHIBIT MOST OF THE ACTIVITY ACROSS THE SRN CWA BY 18Z. WE SHOULD SEE A WELL DEVELOPED BAND OF RAIN/THUNDERSTORMS FROM SE NDAK INTO NWRN MN. THIS WILL BE OCCURRING ON NWRN SIDE OF SFC LOW IN AN AREA OF DIVERGENCE ALOFT SUPPLIED BY RIGHT ENTRANCE REGION OF UPPER JET.THIS CORRIDOR OF DEEP LAYER LIFT WILL TEND TO REMAIN OVER THE SAME REGION THROUGH THE AFTERNOON. SIGNIFICANT RAINFALL MAY OCCUR AND WE WILL NEED TO WATCH KOOCH/NWRN ITASCA COUNTY AREA FOR ADDITIONAL UPDATES. TONIGHT/TOMORROW...NRN BRANCH OF WESTERLIES WILL ADVANCE ACROSS CWA OVERNIGHT. THIS WILL PUSH FRNTL SYSTEM THROUGH AS SFC HIGH BUILDS INTO CWA FROM NRN PLAINS. DEEP LAYER DRYING REFLECTED IN INTEGRATED RH PRODUCTS AND MDL XSECTS. SHOULD SEE MOSTLY SUNNY SKIES ADVANCING ACROSS CWA AS DAY UNFOLDS. WITH INCREASED MIXING DURING DAY...UNIDIRECTIONAL FLOW IN LOWEST 5K FT....SHOULD SEE SOME GUSTY WINDS DEVELOPING. SFC DEWPOINTS MAY NEED LOWERING AS MIX DOWN OF DRIER AIR OCCURS IN AFTN. .EXTENDED...TUESDAY NIGHT THROUGH SUNDAY... UPPER LEVEL AND SFC RIDGING WILL COVER THE FA TUESDAY NIGHT THROUGH FRIDAY. THE RIDGING MOVES JUST E OF THE AREA FRIDAY AFTERNOON ALLOWING FOR A SOUTHERLY WAA/RETURN FLOW PATTERN TO BECOME ESTABLISHED. A SHORT WAVE TROF WILL MOVE FROM THE NORTHERN PLAINS FRIDAY NIGHT INTO THE GREAT LAKES SATURDAY NIGHT. IN THE MEANTIME...AN ASSOCIATED SFC LOW MOVING THROUGH SOUTHERN CANADA WILL PUSH A COLD FRONT THROUGH THE FA AND EXIT SATURDAY NIGHT. THIS COMBINATION WARRANTS SOME POPS FRIDAY NIGHT THROUGH SUNDAY. BEST INSTABILITY WILL BE FOUND OVER THE SOUTHERN THIRD OF THE AREA SATURDAY AND HAVE A MENTION OF THUNDERSTORMS. AVIATION...06Z TAFS IFR/MVFR CEILINGS WILL OCCUR IN SPOTS THROUGH THE PERIOD...MOST LIKELY AROUND LAKE SUPERIOR. SOME FOG WILL ALSO BE POSSIBLE...ALTHOUGH SB`S HAVE INCREASED IN MOST AREAS DUE TO STRONG HIGH BUILDING SOUTH THROUGH ONTARIO. SHOWERS/STORMS WERE DEVELOPING JUST WEST OF KDLH...ON WEST TO NEAR KDTL. PERSISTENT WAA/MOISTURE TRANSPORT SHOULD LEAD TO ADDITIONAL SHOWER/STORM DEVELOPMENT OVERNIGHT INTO MONDAY. MVFR OR EVEN SOME IFR CONDITIONS WILL BE POSSIBLE WITH ANY SHOWERS/STORMS. STORMS SHOULD OCCUR MAINLY OVER NORTHEAST/NORTHERN MINNESOTA THROUGH MUCH OF MONDAY...TRANSLATING EAST MONDAY NIGHT. .POINT TEMPS/POPS... DLH 52 40 58 35 / 60 60 10 0 INL 51 36 58 30 / 60 60 10 0 BRD 63 41 61 34 / 50 60 10 0 HYR 62 42 61 33 / 20 60 20 0 ASX 57 41 57 34 / 60 60 20 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR LSZ121- 140>148. && $$ SHORT TERM...CANNON LONG TERM....GSF
AREA FORECAST DISCUSSION
NWS JACKSON MS
457 PM CDT MON APR 2 2012 .UPDATE...HAVE EXPANDED THE AREAL COVERAGE OF SVR WATCH 128 TO INCLUDE THE AREA FROM GRENADA TO KEMPER AND POINTS SWWD AS THE LINE OF SEVERE STORMS CONTINUES TO TRACK TO THE NE THIS EVENING. LOCATIONS IN THE EXPANDED AREA ARE IN A REGION OF PRESSURE FALLS AND -4 TO -5 LIFTED INDICES. ALSO CLEARED A FEW COUNTIES FROM THE WATCH OVER SWRN ZONES IN THE STRATIFORM RAIN SHIELD BEHIND THE LINE. && .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...COMPLICATED FORECAST IN THE SHORT TERM AS SEVERAL POTENTIAL ROUNDS OF STORMS WILL BE POSSIBLE OVER THE NEXT FEW DAYS. CURRENT RADARS SHOW BROKEN LINE OF SHOWERS AND THUNDERSTORMS MOVING NORTHWARD THROUGH THE CWA...GENERALLY FROM BASTROP TO THE JACKSON METRO AREA TO JUST NORTH OF HATTIESBURG. THERE ARE ALSO SOME STORMS BEHIND THIS LINE MOVING NORTH FROM PIKE AND AMITE COUNTIES IN LOUISIANA. THIS MAIN LINE IS PRODUCING SEVERE WIND DAMAGE WITH MOST REPORTS BEING TREES COMING DOWN AND SOME QUARTER SIZE HAIL AS IT CONTINUES NORTH THROUGH AN UNSTABLE ATMOSPHERE CHARACTERIZED BY 3500-4000 J/KG SBCAPE...2000-2600 J/KG MLCAPE...28-29C VERTICAL TOTALS...AND -8 TO -12 SFC LI PER RUC ANALYSIS. THIS UNSTABLE AIRMASS HAS HELPED TO SUSTAIN THE SEVERITY OF THE LINE OF STORMS AS IT MOVED OUT OF THE LAKE CHARLES LOUISIANA AREA EARLIER THIS MORNING. THIS LINE IS EXPECTED TO REMAIN SEVERE AS IT CONTINUES TO THE NORTH AND EAST UNTIL DAYTIME HEATING IS ABLE TO REDUCE INSTABILITY OVER THE AREA. SEVERE THUNDERSTORM WATCH CONTINUES FOR PORTIONS OF THE AREA...AND WAS EVEN EXPANDED TO INCLUDE MORE OF THE PINE BELT REGION THROUGH 8PM. HI-RES WRF MODELS AS WELL AS GLOBAL MODELS INDICATE THAT THIS ACTIVITY WILL BE WANING THROUGH THE EVENING AND OVERNIGHT AS INSTABILITY WANES AND THE SHORTWAVE TROUGH LIFTS OFF TO THE NORTH. THERE IS SOME POTENTIAL FOR PATCHY FOG TONIGHT SOUTH OF I-20 AS MOISTURE CONTINUES TO BUILD INTO THE REGION AND WINDS DIMINISH LATER IN THE NIGHT. FOR TUESDAY...THERE REMAINS SOME UNCERTAINTY AS TO HOW STORMS WILL EVOLVE. MODELS SHOW SHORTWAVE RIDGING MOVING INTO THE AREA...WHICH SHOULD SUPPRESS MOST CONVECTION. IN ADDITION...THERE IS SOME CONCERN AS TO HOW THE SYSTEM GOING THROUGH TODAY WILL POTENTIALLY AFFECT TOMORROW. THERE WILL BE ENOUGH INSTABILITY AS TEMPERATURES REACH INTO THE 80S ONCE AGAIN. MUCAPE VALUES ARE PROGGED TO BE AROUND 1800-2000J/KG...28-29C VERTICAL TOTALS...BUT WIND SHEAR WILL AGAIN BE RATHER WEAK AS WELL AS MID LEVEL FLOW. WHATEVER BOUNDARIES THIS SYSTEM TODAY LEAVES AROUND COULD BE A FOCUS FOR ANY ADDITIONAL SHOWERS AND THUNDERSTORMS TOMORROW. GIVEN THE WEAK FLOW...THESE STORMS WOULD BE OF PULSE TYPE VARIETY. HAVE GONE WITH SLIGHT CHANCE POPS FOR TOMORROW GIVEN UNCERTAINTY IN STORM COVERAGE. THE BETTER POTENTIAL FOR SHOWERS AND STORMS STILL LOOKS TO BE ON WEDNESDAY. THERE STILL REMAINS UNCERTAINTY IN TIMING AND HOW MUCH COVERAGE WE WILL SEE. HOWEVER...PARAMETERS LOOK BETTER IN TERMS OF WIND SHEAR...MID LEVEL FLOW...LAPSE RATES THAN THEY HAVE FOR THE PREVIOUS DAYS. WHILE VALUES OF SHEAR ARE STILL NOT OVERLY IMPRESSIVE WHICH COULD PRECLUDE ORGANIZED THUNDERSTORM ACTIVITY...GIVEN THE FORCING AND LIFT FROM THE UPPER LOW TRACKING CLOSER...WE COULD SEE ADDITIONAL STRONG TO SEVERE STORMS AND WILL CONTINUE TO MENTION THIS IN THE HWO/GRAPHICS. THE BEST LIFT SHOULD CONTINUE TO MOVE EAST OF THE AREA BY THURSDAY MORNING...AND END MOST OF THE THUNDERSTORM ACTIVITY. /28/ .LONG TERM...THURSDAY THROUGH MONDAY...DEPENDING ON THE TRACK OF THE MID LEVEL LOW...THERE COULD BE ENOUGH INSTABILITY THURSDAY INTO THURSDAY NIGHT TO GET REDEVELOPMENT OF MOSTLY DIURNAL SHOWER/ISOLATED THUNDERSTORM ACTIVITY...PARTICULARLY OVER NE PORTIONS OF THE FORECAST AREA. OTHERWISE...IN THE WAKE OF THE DEPARTING LOW...EXPECT THE STUBBORN MID LEVEL RIDGE TO REBUILD OVER THE FORECAST AREA AS WE GO INTO NEXT WEEKEND RESULTING IN MORE WARM AND DRY CONDITIONS. /EC/ && .AVIATION...VFR CONDITIONS ONGOING THIS AFTERNOON BUT SHOWERS AND THUNDERSTORMS MOVING NORTH THROUGH THE AREA BRINGING LOCALIZED MVFR TO IFR CONDITIONS FOR LOW CEILINGS AND VIS. THESE STORMS BRINGING GUSTY WINDS UP TO 60 MPH AND POTENTIAL FOR LARGE HAIL TO GOLFBALL SIZE. THE RISK FOR THUNDERSTORMS AND RAIN WILL WANE THROUGH THE EVENING AFTER 01-02Z. AREAS OF MVFR/IFR STRATUS/FOG WILL REDEVELOP AGAIN LATE TONIGHT INTO EARLY TUESDAY MORNING BEFORE DISSIPATING AFTER ABOUT 15Z TUESDAY. /28/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 62 85 65 82 / 51 20 22 55 MERIDIAN 61 87 61 81 / 43 23 12 46 VICKSBURG 62 86 64 82 / 40 16 33 58 HATTIESBURG 64 88 65 83 / 41 17 18 50 NATCHEZ 64 85 66 83 / 21 16 38 63 GREENVILLE 64 85 65 85 / 51 17 44 55 GREENWOOD 65 85 66 84 / 46 23 36 55 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 28/EC/03
AREA FORECAST DISCUSSION
NWS JACKSON MS
410 PM CDT MON APR 2 2012 .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...COMPLICATED FORECAST IN THE SHORT TERM AS SEVERAL POTENTIAL ROUNDS OF STORMS WILL BE POSSIBLE OVER THE NEXT FEW DAYS. CURRENT RADARS SHOW BROKEN LINE OF SHOWERS AND THUNDERSTORMS MOVING NORTHWARD THROUGH THE CWA...GENERALLY FROM BASTROP TO THE JACKSON METRO AREA TO JUST NORTH OF HATTIESBURG. THERE ARE ALSO SOME STORMS BEHIND THIS LINE MOVING NORTH FROM PIKE AND AMITE COUNTIES IN LOUISIANA. THIS MAIN LINE IS PRODUCING SEVERE WIND DAMAGE WITH MOST REPORTS BEING TREES COMING DOWN AND SOME QUARTER SIZE HAIL AS IT CONTINUES NORTH THROUGH AN UNSTABLE ATMOSPHERE CHARACTERIZED BY 3500-4000 J/KG SBCAPE...2000-2600 J/KG MLCAPE...28-29C VERTICAL TOTALS...AND -8 TO -12 SFC LI PER RUC ANALYSIS. THIS UNSTABLE AIRMASS HAS HELPED TO SUSTAIN THE SEVERITY OF THE LINE OF STORMS AS IT MOVED OUT OF THE LAKE CHARLES LOUISIANA AREA EARLIER THIS MORNING. THIS LINE IS EXPECTED TO REMAIN SEVERE AS IT CONTINUES TO THE NORTH AND EAST UNTIL DAYTIME HEATING IS ABLE TO REDUCE INSTABILITY OVER THE AREA. SEVERE THUNDERSTORM WATCH CONTINUES FOR PORTIONS OF THE AREA...AND WAS EVEN EXPANDED TO INCLUDE MORE OF THE PINE BELT REGION THROUGH 8PM. HI-RES WRF MODELS AS WELL AS GLOBAL MODELS INDICATE THAT THIS ACTIVITY WILL BE WANING THROUGH THE EVENING AND OVERNIGHT AS INSTABILITY WANES AND THE SHORTWAVE TROUGH LIFTS OFF TO THE NORTH. THERE IS SOME POTENTIAL FOR PATCHY FOG TONIGHT SOUTH OF I-20 AS MOISTURE CONTINUES TO BUILD INTO THE REGION AND WINDS DIMINISH LATER IN THE NIGHT. FOR TUESDAY...THERE REMAINS SOME UNCERTAINTY AS TO HOW STORMS WILL EVOLVE. MODELS SHOW SHORTWAVE RIDGING MOVING INTO THE AREA...WHICH SHOULD SUPPRESS MOST CONVECTION. IN ADDITION...THERE IS SOME CONCERN AS TO HOW THE SYSTEM GOING THROUGH TODAY WILL POTENTIALLY AFFECT TOMORROW. THERE WILL BE ENOUGH INSTABILITY AS TEMPERATURES REACH INTO THE 80S ONCE AGAIN. MUCAPE VALUES ARE PROGGED TO BE AROUND 1800-2000J/KG...28-29C VERTICAL TOTALS...BUT WIND SHEAR WILL AGAIN BE RATHER WEAK AS WELL AS MID LEVEL FLOW. WHATEVER BOUNDARIES THIS SYSTEM TODAY LEAVES AROUND COULD BE A FOCUS FOR ANY ADDITIONAL SHOWERS AND THUNDERSTORMS TOMORROW. GIVEN THE WEAK FLOW...THESE STORMS WOULD BE OF PULSE TYPE VARIETY. HAVE GONE WITH SLIGHT CHANCE POPS FOR TOMORROW GIVEN UNCERTAINTY IN STORM COVERAGE. THE BETTER POTENTIAL FOR SHOWERS AND STORMS STILL LOOKS TO BE ON WEDNESDAY. THERE STILL REMAINS UNCERTAINTY IN TIMING AND HOW MUCH COVERAGE WE WILL SEE. HOWEVER...PARAMETERS LOOK BETTER IN TERMS OF WIND SHEAR...MID LEVEL FLOW...LAPSE RATES THAN THEY HAVE FOR THE PREVIOUS DAYS. WHILE VALUES OF SHEAR ARE STILL NOT OVERLY IMPRESSIVE WHICH COULD PRECLUDE ORGANIZED THUNDERSTORM ACTIVITY...GIVEN THE FORCING AND LIFT FROM THE UPPER LOW TRACKING CLOSER...WE COULD SEE ADDITIONAL STRONG TO SEVERE STORMS AND WILL CONTINUE TO MENTION THIS IN THE HWO/GRAPHICS. THE BEST LIFT SHOULD CONTINUE TO MOVE EAST OF THE AREA BY THURSDAY MORNING...AND END MOST OF THE THUNDERSTORM ACTIVITY. /28/ .LONG TERM...THURSDAY THROUGH MONDAY...DEPENDING ON THE TRACK OF THE MID LEVEL LOW...THERE COULD BE ENOUGH INSTABILITY THURSDAY INTO THURSDAY NIGHT TO GET REDEVELOPMENT OF MOSTLY DIURNAL SHOWER/ISOLATED THUNDERSTORM ACTIVITY...PARTICULARLY OVER NE PORTIONS OF THE FORECAST AREA. OTHERWISE...IN THE WAKE OF THE DEPARTING LOW...EXPECT THE STUBBORN MID LEVEL RIDGE TO REBUILD OVER THE FORECAST AREA AS WE GO INTO NEXT WEEKEND RESULTING IN MORE WARM AND DRY CONDITIONS. /EC/ && .AVIATION...VFR CONDITIONS ONGOING THIS AFTERNOON BUT SHOWERS AND THUNDERSTORMS MOVING NORTH THROUGH THE AREA BRINGING LOCALIZED MVFR TO IFR CONDITIONS FOR LOW CEILINGS AND VIS. THESE STORMS BRINGING GUSTY WINDS UP TO 60 MPH AND POTENTIAL FOR LARGE HAIL TO GOLFBALL SIZE. THE RISK FOR THUNDERSTORMS AND RAIN WILL WANE THROUGH THE EVENING AFTER 01-02Z. AREAS OF MVFR/IFR STRATUS/FOG WILL REDEVELOP AGAIN LATE TONIGHT INTO EARLY TUESDAY MORNING BEFORE DISSIPATING AFTER ABOUT 15Z TUESDAY. /28/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 62 85 65 82 / 51 20 22 55 MERIDIAN 61 87 61 81 / 43 23 12 46 VICKSBURG 62 86 64 82 / 40 16 33 58 HATTIESBURG 64 88 65 83 / 41 17 18 50 NATCHEZ 64 85 66 83 / 21 16 38 63 GREENVILLE 64 85 65 85 / 51 17 44 55 GREENWOOD 65 85 66 84 / 46 23 36 55 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 28/EC
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
345 AM CDT MON APR 2 2012 .SHORT TERM... ISSUED AT 341 AM CDT MON APR 2 2012 (TODAY) MAIN QUESTION FOR TODAY WILL BE HOW WARM WILL IT GET. CURRENTLY HAVE A BACKDOOR COLD FRONT STALLED OUT OVER FORECAST AREA. IT EXTENDS FROM NORTHWESTERN MO THROUGH MEXICO MO THEN EASTWARD INTO SOUTHERN IL...JUST NORTH OF ST. LOUIS METRO AREA. BELIEVE IT WILL SLOWLY WEAKEN AND WASH OUT OVER TIME TODAY...WITH WINDS PICKING UP FROM THE SOUTH. SO TEMPS TO WARM UP INTO THE MID TO UPPER 80S...SIMILAR TO YESTERDAY WITH RECORD OR NEAR RECORD HIGHS. IF AIR MASS RECOVERS FASTER THAN CURRENT THINKING...COULD SEE TEMPS WARM UP INTO THE LOWER 90S. AS FOR ANY CLOUD COVER...SHOULD BE A MOSTLY SUNNY DAY...WITH PERHAPS A FEW MORE CLOUDS OVER NORTHEASTERN PORTIONS OF FORECAST AREA...CLOSER TO BACKDOOR COLD FRONT. BYRD && .LONG TERM... ISSUED AT 345 AM CDT MON APR 2 2012 (TONIGHT THROUGH SUNDAY) A LONGWAVE UPPER RIDGE WILL CONTINUE TO PERSIST OUR REGION INTO NEXT WEEKEND. NORMALLY THIS PATTERN WOULD FORETELL MAINLY DRY WX AND ABOVE AVERAGE TEMPS...BUT A STRONG STORM SYSTEM OVER THE SWRN CONUS THAT IS IN THE PROCESS OF GETTING CUTOFF FROM THE MAIN FLOW WILL FOIL MUCH OF THAT FOR MID AND LATE WEEK WITH WHAT SHOULD BE A WET PERIOD WITH TEMPS CLOSER TO AVERAGE FOR THIS TIME OF YEAR. WHILE AN ARGUMENT CAN BE MADE THAT MUCH ABOVE AVERAGE TEMPS HAVE BECOME THE NEW NORMAL RECENTLY...AVERAGE TEMPS WERE LAST SEEN IN OUR AREA ABOUT FOUR WEEKS AGO...SO COULD BE A MOMENTUS OCCASION. IN THE MEANTIME...TONIGHT IS LOOKING INCREASINGLY DRY AND CLEAR AS FRONT IS FURTHER DELAYED FROM THE NW AND WHAT SHOULD BE A DORMANT LEAD IMPULSE SHOULD FALL SHORT OF THE SWRN FA BY 12Z/TUES. TUESDAY TRENDS REMAIN SIMILAR TO BEFORE...AS LEAD IMPULSE TRACKS THRU MAINLY SERN MO AND SRN IL SHOULD SPAWN NUMEROUS TSRA DURING THE HEATING OF THE DAY IN A REGIME THAT CONSISTS OF A VERY MOIST AND MODERATELY UNSTABLE ATMOSPHERE WITH NO CAP. FRONT EDGING INTO NRN MO AND CNTRL IL SHOULD ALSO BE ABLE TO RESULT IN SCT CONVECTION. VORT MAX DRIVEN ACTIVITY WILL DIMINISH/EXIT TO THE E-SE TUESDAY EVENING WHILE ACTIVITY ALONG THE FRONT TO THE N WILL ALSO RECEDE. TUESDAY NIGHT OTHERWISE DID LOOK LIKE A PERIOD OF DOWNTIME FROM PCPN...BUT LATEST MODELS INDICATE THE INITIAL BAND OF SHRA/TSRA FROM MAIN CUTOFF LO TO THE W WILL EDGE THE SWRN FA. TUESDAY TEMPS HAVE BEEN BUMPED UP SIGNFICANTLY WITH FRONT MUCH DELAYED AND ENOUGH SUN BEFORE BETTER TSRA CHCS LATER IN THE AFTN...TO RESULT IN WIDESPREAD TEMPS IN THE 80-85 RANGE...REFLECTING THE EARLIER TRENDS OF THE MAV MOS. WEDNESDAY THRU THURSDAY LOOKS TO BE THE BEST CHC FOR WIDESPREAD PCPN...WITH TEMPS BACKING OFF TOWARDS AVERAGE BY THURSDAY...AND PROBABLY AGAIN ON FRIDAY WITH LEFTOVER CLOUDS AND BUILDING CANADIAN HI PRES FROM THE NE. ONCE THE CUTOFF SYSTEM EXITS OUR REGION...LONGWAVE RIDGE WILL RE-ASSUME ITS DOMINANCE AND EVEN DEFLECT A SHORTWAVE TO OUR N FOR NEXT WEEKEND. HOWEVER...SFC FRONTAL BOUNDARY EXPECTED TO SETTLE IN DURING NEXT WEEKEND COULD RESULT IN EXTENDED RAIN CHCS AGAIN. 30PCT IS CLIMO FOR THIS TIME OF YEAR...AND WITH FRONTAL BOUNDARY INVOF OUR REGION...HAVE 30-40PCT GOING FOR BOTH SATURDAY AND SUNDAY. TES && .AVIATION... ISSUED AT 1129 PM CDT SUN APR 1 2012 STILL CONCERNED THAT THERE COULD BE SOME STRATUS DEVELOPMENT AFTER 09Z OVER THE OZARKS AND SPREADING NORTH INTO CENTRAL AND EASTERN MISSOURI AS WELL AS SOUTHWEST ILLINOIS. BASICALLY NOTHING HAS CHANGED FROM EARLIER...WITH SOME GUIDANCE HINTING AT STRATUS AND OTHERS STAYING CLEAR. WILL OPT FOR STATUS QUO AT THIS TIME AND KEEP SCATTERED 1200FT IN STL METRO TAFS AS WELL AS COLUMBIA. ADDITIONALLY...A LOW LEVEL JET STREAK IS TRYING TO RAMP UP OVER CENTRAL MISSOURI ACCORDING TO THE NAM AND RUC MODELS BRINGING WIND SPEEDS UP TO AROUND 40KTS AT 1000FT SO WILL INCLUDE LLWS IN THE COU TAF UNTIL THE JET STREAK WEAKENS IN A FEW HOURS. OTHERWISE...EXPECT LIGHT AND VARIABLE SURFACE WINDS WITH VFR FLIGHT CONDITIONS FOR THE REST OF THE NIGHT. WIND WILL PICK UP FROM THE SOUTH-SOUTHWEST AGAIN MONDAY WITH VFR FLIGHT CONDITIONS CONTINUING. SPECIFICS FOR KSTL...STILL CONCERNED THAT THERE COULD BE SOME STRATUS DEVELOPMENT AFTER 09Z OVER THE OZARKS AND SPREADING NORTH INTO THE VICINITY OF LAMBERT FIELD BEFORE SUNRISE. BASICALLY NOTHING HAS CHANGED FROM EARLIER...WITH SOME GUIDANCE HINTING AT STRATUS AND OTHERS STAYING CLEAR. WILL OPT FOR STATUS QUO AT THIS TIME AND KEEP SCATTERED 1200FT IN AT LAMBERT. OTHERWISE...EXPECT LIGHT AND VARIABLE SURFACE WINDS WITH VFR FLIGHT CONDITIONS FOR THE REST OF THE NIGHT. WIND WILL PICK UP FROM THE SOUTH-SOUTHWEST AGAIN MONDAY WITH VFR FLIGHT CONDITIONS CONTINUING. CARNEY && .CLIMATE... ISSUED AT 345 AM CDT MON APR 2 2012 RECORD MAX AND HI MIN TEMPS FOR TODAY SAINT LOUIS (KSTL) 88/1946 68/1946 COLUMBIA (KCOU) 85/1946 65/1956 QUINCY (KUIN) 85/1940 62/1963 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
341 AM CDT MON APR 2 2012 .SHORT TERM... ISSUED AT 341 AM CDT MON APR 2 2012 (TODAY) MAIN QUESTION FOR TODAY WILL BE HOW WARM WILL IT GET. CURRENTLY HAVE A BACKDOOR COLD FRONT STALLED OUT OVER FORECAST AREA. IT EXTENDS FROM NORTHWESTERN MO THROUGH MEXICO MO THEN EASTWARD INTO SOUTHERN IL...JUST NORTH OF ST. LOUIS METRO AREA. BELIEVE IT WILL SLOWLY WEAKEN AND WASH OUT OVER TIME TODAY...WITH WINDS PICKING UP FROM THE SOUTH. SO TEMPS TO WARM UP INTO THE MID TO UPPER 80S...SIMILAR TO YESTERDAY WITH RECORD OR NEAR RECORD HIGHS. IF AIR MASS RECOVERS FASTER THAN CURRENT THINKING...COULD SEE TEMPS WARM UP INTO THE LOWER 90S. AS FOR ANY CLOUD COVER...SHOULD BE A MOSTLY SUNNY DAY...WITH PERHAPS A FEW MORE CLOUDS OVER NORTHEASTERN PORTIONS OF FORECAST AREA...CLOSER TO BACKDOOR COLD FRONT. BYRD && .LONG TERM... ISSUED AT 313 PM CDT SUN APR 1 2012 (MONDAY THROUGH NEXT SUNDAY) TOMORROW STILL LOOKS THAT IT WILL BE AS WARM AS TODAY IF NOT A BIT WARMER WITH RECORD OR NEAR RECORD HIGHS. CURRENT (3 PM) TEMPS ARE IN THE MID TO UPPER 80S. LOWS TOMORROW MORNING OVER MUCH OF THE AREA ARE EXPECTED TO BE ABOUT 3-6 DEGREES WARMER THAN THIS MORNING. FORECAST SOUNDINGS STILL INDICATE THAT WE SHOULD MIX UP TO AROUND 850MB WHERE TEMPERATURES WILL BE 18-21C RANGE. ANY CLOUDS AROUND IN THE MORNING SHOULD THIN OUT BY LATE MORNING ALLOWING MAINLY SUNNY SKIES. THIS SUPPORTS TEMPERATURES IN THE UPPER 80S TO AROUND 90...ESPECIALLY FROM THE ST. METRO AREA WESTWARD WHERE A SOUTH SOUTHWESTERLY WINDS WILL FAVOR SLIGHTLY WARMER TEMPERATURES IN THE LEE OF THE OZARKS. RAIN CHANCES STILL LOOK TO BE SUPPRESSED THROUGH MONDAY NIGHT WITH AN UPPER RIDGE OVER THE AREA. HAVE LEANED TOWARD THE ECMWF FOR MOST OF THE FORECAST AS IT HAS BEEN THE MOST CONSISTENT WITH THE PLACEMENT OF THE UPPER LOW AND THE DEPICTION OF THE SURFACE FRONT THAT WILL MOVE ACROSS THE AREA ON TUESDAY. THE 500MB TROUGH THAT THE GFS IS BRINGING INTO EASTERN MO ON TUESDAY LOOKS TO BE OVERLY INFLUENCED BY CONVECTIVE FEEDBACK. WITH THIS IN MIND...HAVE KEPT LIKELY POPS OVER THE SOUTHERN CWA ON TUESDAY AFTERNOON WHERE THE FRONT WILL BE DURING THE MOST UNSTABLE TIME OF THE DAY. I THEN KEEP CHANCES OF STORMS OVER SOUTHEASTERN MO INTO SOUTHERN IL ON TUESDAY NIGHT CLOSE TO WHERE THE FRONT WILL STALL OUT. A 500MB LOW WILL THEN MOVE FROM THE CENTRAL HIGH PLAINS ON TUESDAY EVENING INTO THE MID SOUTH BY LATE THURSDAY. HAVE KEPT LIKELY POPS GOING WEDNESDAY AND WEDNESDAY NIGHT WHEN STRONG LARGE SCALE ASCENT FROM THE UPPER LOW WILL COINCIDE WITH DECENT LOW LEVEL MOISTURE CONVERGENCE ON THE NORTHERN SIDE OF ITS TRACK. DRY WEATHER STILL LOOKS LIKE IT WILL SET IN LATE THURSDAY INTO FRIDAY IN THE WAKE OF THE LOW. THE ECMWF HAS COME INTO AGREEMENT WITH THE GFS ON THE POTENTIAL FOR SCATTERED SHRA/TSRA ON SATURDAY AS ANOTHER COLD FRONT MOVES ACROSS MO/IL. WHILE IT WILL BE COOLER ON TUESDAY...TEMPERATURES WILL STILL BE WAY ABOVE NORMAL WITH THE SLOWER FRONTAL PASSAGE. TEMPERATURES WILL BE NEAR NORMAL BEHIND THE FRONT ON WEDNESDAY AND THURSDAY WITH THE CLOUDS AND RAIN CHANCES. BRITT && .AVIATION... ISSUED AT 1129 PM CDT SUN APR 1 2012 STILL CONCERNED THAT THERE COULD BE SOME STRATUS DEVELOPMENT AFTER 09Z OVER THE OZARKS AND SPREADING NORTH INTO CENTRAL AND EASTERN MISSOURI AS WELL AS SOUTHWEST ILLINOIS. BASICALLY NOTHING HAS CHANGED FROM EARLIER...WITH SOME GUIDANCE HINTING AT STRATUS AND OTHERS STAYING CLEAR. WILL OPT FOR STATUS QUO AT THIS TIME AND KEEP SCATTERED 1200FT IN STL METRO TAFS AS WELL AS COLUMBIA. ADDITIONALLY...A LOW LEVEL JET STREAK IS TRYING TO RAMP UP OVER CENTRAL MISSOURI ACCORDING TO THE NAM AND RUC MODELS BRINGING WIND SPEEDS UP TO AROUND 40KTS AT 1000FT SO WILL INCLUDE LLWS IN THE COU TAF UNTIL THE JET STREAK WEAKENS IN A FEW HOURS. OTHERWISE...EXPECT LIGHT AND VARIABLE SURFACE WINDS WITH VFR FLIGHT CONDITIONS FOR THE REST OF THE NIGHT. WIND WILL PICK UP FROM THE SOUTH-SOUTHWEST AGAIN MONDAY WITH VFR FLIGHT CONDITIONS CONTINUING. SPECIFICS FOR KSTL... STILL CONCERNED THAT THERE COULD BE SOME STRATUS DEVELOPMENT AFTER 09Z OVER THE OZARKS AND SPREADING NORTH INTO THE VICINITY OF LAMBERT FIELD BEFORE SUNRISE. BASICALLY NOTHING HAS CHANGED FROM EARLIER...WITH SOME GUIDANCE HINTING AT STRATUS AND OTHERS STAYING CLEAR. WILL OPT FOR STATUS QUO AT THIS TIME AND KEEP SCATTERED 1200FT IN AT LAMBERT. OTHERWISE...EXPECT LIGHT AND VARIABLE SURFACE WINDS WITH VFR FLIGHT CONDITIONS FOR THE REST OF THE NIGHT. WIND WILL PICK UP FROM THE SOUTH-SOUTHWEST AGAIN MONDAY WITH VFR FLIGHT CONDITIONS CONTINUING. CARNEY && .CLIMATE... ISSUED AT 315 AM CDT SUN MAR 31 2012 SAINT LOUIS...COLUMBIA...AND QUINCY HAVE INDEED SET ALL-TIME MARCH RECORDS FOR HIGHEST AVERAGE TEMPERATURE OVER THE COURSE OF THE ENTIRE MONTH...AND NOT BARELY EITHER...BUT BY A LARGE MARGIN. PLEASE SEE THE MONTHLY CLIMATE SUMMARIES (CLMSTL AND CLMCOU) FOR ADDITIONAL INFORMATION. RECORD MAX AND HI MIN TEMPS FOR EARLY APRIL 4/1 4/2 SAINT LOUIS (KSTL) 91/1946 70/1946 88/1946 68/1946 COLUMBIA (KCOU) 88/1946 65/1946 85/1946 65/1956 QUINCY (KUIN) 86/2010 62/1963 85/1940 62/1963 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1152 PM CDT SUN APR 1 2012 .SHORT TERM... ISSUED AT 313 PM CDT SUN APR 1 2012 (TONIGHT) UNSEASONABLY WARM TEMPERATURES ARE EXPECTED AGAIN TONIGHT WITH OVERNIGHT LOWS FCST TO BE APPROXIMATELY 20-25 DEG F ABOVE AVERAGE FOR THIS TIME OF YEAR. MOISTURE ADVECTION AHEAD OF A DEVELOPING LOW PRESSURE SYSTEM MAY CAUSE SOME STRATUS TO DEVELOP AND ADVECT NWD OVERNIGHT. KANOFSKY && .LONG TERM... ISSUED AT 313 PM CDT SUN APR 1 2012 (MONDAY THROUGH NEXT SUNDAY) TOMORROW STILL LOOKS THAT IT WILL BE AS WARM AS TODAY IF NOT A BIT WARMER WITH RECORD OR NEAR RECORD HIGHS. CURRENT (3 PM) TEMPS ARE IN THE MID TO UPPER 80S. LOWS TOMORROW MORNING OVER MUCH OF THE AREA ARE EXPECTED TO BE ABOUT 3-6 DEGREES WARMER THAN THIS MORNING. FORECAST SOUNDINGS STILL INDICATE THAT WE SHOULD MIX UP TO AROUND 850MB WHERE TEMPERATURES WILL BE 18-21C RANGE. ANY CLOUDS AROUND IN THE MORNING SHOULD THIN OUT BY LATE MORNING ALLOWING MAINLY SUNNY SKIES. THIS SUPPORTS TEMPERATURES IN THE UPPER 80S TO AROUND 90...ESPECIALLY FROM THE ST. METRO AREA WESTWARD WHERE A SOUTH SOUTHWESTERLY WINDS WILL FAVOR SLIGHTLY WARMER TEMPERATURES IN THE LEE OF THE OZARKS. RAIN CHANCES STILL LOOK TO BE SUPPRESSED THROUGH MONDAY NIGHT WITH AN UPPER RIDGE OVER THE AREA. HAVE LEANED TOWARD THE ECMWF FOR MOST OF THE FORECAST AS IT HAS BEEN THE MOST CONSISTENT WITH THE PLACEMENT OF THE UPPER LOW AND THE DEPICTION OF THE SURFACE FRONT THAT WILL MOVE ACROSS THE AREA ON TUESDAY. THE 500MB TROUGH THAT THE GFS IS BRINGING INTO EASTERN MO ON TUESDAY LOOKS TO BE OVERLY INFLUENCED BY CONVECTIVE FEEDBACK. WITH THIS IN MIND...HAVE KEPT LIKELY POPS OVER THE SOUTHERN CWA ON TUESDAY AFTERNOON WHERE THE FRONT WILL BE DURING THE MOST UNSTABLE TIME OF THE DAY. I THEN KEEP CHANCES OF STORMS OVER SOUTHEASTERN MO INTO SOUTHERN IL ON TUESDAY NIGHT CLOSE TO WHERE THE FRONT WILL STALL OUT. A 500MB LOW WILL THEN MOVE FROM THE CENTRAL HIGH PLAINS ON TUESDAY EVENING INTO THE MID SOUTH BY LATE THURSDAY. HAVE KEPT LIKELY POPS GOING WEDNESDAY AND WEDNESDAY NIGHT WHEN STRONG LARGE SCALE ASCENT FROM THE UPPER LOW WILL COINCIDE WITH DECENT LOW LEVEL MOISTURE CONVERGENCE ON THE NORTHERN SIDE OF ITS TRACK. DRY WEATHER STILL LOOKS LIKE IT WILL SET IN LATE THURSDAY INTO FRIDAY IN THE WAKE OF THE LOW. THE ECMWF HAS COME INTO AGREEMENT WITH THE GFS ON THE POTENTIAL FOR SCATTERED SHRA/TSRA ON SATURDAY AS ANOTHER COLD FRONT MOVES ACROSS MO/IL. WHILE IT WILL BE COOLER ON TUESDAY...TEMPERATURES WILL STILL BE WAY ABOVE NORMAL WITH THE SLOWER FRONTAL PASSAGE. TEMPERATURES WILL BE NEAR NORMAL BEHIND THE FRONT ON WEDNESDAY AND THURSDAY WITH THE CLOUDS AND RAIN CHANCES. BRITT && .AVIATION... ISSUED AT 1129 PM CDT SUN APR 1 2012 STILL CONCERNED THAT THERE COULD BE SOME STRATUS DEVELOPMENT AFTER 09Z OVER THE OZARKS AND SPREADING NORTH INTO CENTRAL AND EASTERN MISSOURI AS WELL AS SOUTHWEST ILLINOIS. BASICALLY NOTHING HAS CHANGED FROM EARLIER...WITH SOME GUIDANCE HINTING AT STRATUS AND OTHERS STAYING CLEAR. WILL OPT FOR STATUS QUO AT THIS TIME AND KEEP SCATTERED 1200FT IN STL METRO TAFS AS WELL AS COLUMBIA. ADDITIONALLY...A LOW LEVEL JET STREAK IS TRYING TO RAMP UP OVER CENTRAL MISSOURI ACCORDING TO THE NAM AND RUC MODELS BRINGING WIND SPEEDS UP TO AROUND 40KTS AT 1000FT SO WILL INCLUDE LLWS IN THE COU TAF UNTIL THE JET STREAK WEAKENS IN A FEW HOURS. OTHERWISE...EXPECT LIGHT AND VARIABLE SURFACE WINDS WITH VFR FLIGHT CONDITIONS FOR THE REST OF THE NIGHT. WIND WILL PICK UP FROM THE SOUTH-SOUTHWEST AGAIN MONDAY WITH VFR FLIGHT CONDITIONS CONTINUING. SPECIFICS FOR KSTL... STILL CONCERNED THAT THERE COULD BE SOME STRATUS DEVELOPMENT AFTER 09Z OVER THE OZARKS AND SPREADING NORTH INTO THE VICINITY OF LAMBERT FIELD BEFORE SUNRISE. BASICALLY NOTHING HAS CHANGED FROM EARLIER...WITH SOME GUIDANCE HINTING AT STRATUS AND OTHERS STAYING CLEAR. WILL OPT FOR STATUS QUO AT THIS TIME AND KEEP SCATTERED 1200FT IN AT LAMBERT. OTHERWISE...EXPECT LIGHT AND VARIABLE SURFACE WINDS WITH VFR FLIGHT CONDITIONS FOR THE REST OF THE NIGHT. WIND WILL PICK UP FROM THE SOUTH-SOUTHWEST AGAIN MONDAY WITH VFR FLIGHT CONDITIONS CONTINUING. CARNEY && .CLIMATE... ISSUED AT 315 AM CDT SUN MAR 31 2012 SAINT LOUIS...COLUMBIA...AND QUINCY HAVE INDEED SET ALL-TIME MARCH RECORDS FOR HIGHEST AVERAGE TEMPERATURE OVER THE COURSE OF THE ENTIRE MONTH...AND NOT BARELY EITHER...BUT BY A LARGE MARGIN. PLEASE SEE THE MONTHLY CLIMATE SUMMARIES (CLMSTL AND CLMCOU) FOR ADDITIONAL INFORMATION. RECORD MAX AND HI MIN TEMPS FOR EARLY APRIL 4/1 4/2 SAINT LOUIS (KSTL) 91/1946 70/1946 88/1946 68/1946 COLUMBIA (KCOU) 88/1946 65/1946 85/1946 65/1956 QUINCY (KUIN) 86/2010 62/1963 85/1940 62/1963 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
448 PM CDT MON APR 2 2012 .UPDATE... SFC LOW PRESSURE APPEARS TO BE TRACKING TOO CLOSE TO EASTERN PORTIONS OF NCNTL NEB FOR STRONG WINDS TO DEVELOP. SO THAT PORTION OF THE WIND ADZY HAS BEEN CANCELLED. NEITHER THE RUC NOR THE HRRR INDICATE 45 MPH GUST BECOMING WIDESPREAD. && .PREV DISCUSSION... /ISSUED 315 PM CDT MON APR 2 2012/ DISCUSSION... A DECISION MAY NEED TO BE MADE ON WHETHER TO CONTINUE THE WIND ADVISORY ALONG HWY 281. THE MODELS ARE TRACKING THE SFC LOW FAR ENOUGH WEST TO PERHAPS PREVENT STRONG WINDS FROM DEVELOPING IN THAT REGION. OTHERWISE THE HIGH WIND WARNING CAN CONTINUE OPERATING ACROSS PARTS OF WRN NEB. HIGH WINDS MIGHT DEVELOP EASTWARD UNTIL 00Z AS MERRIMAN PROFILER SHOWS 2 GATES OF 55KT AT 19Z. WITH CYCLOGENESIS DEVELOPING TONIGHT ACROSS TX AND THE MODELS INDICATING REDEVELOPMENT OF STRATUS ACROSS THE FCST AREA...WIND ADVISORY CONDITIONS ARE EXPECTED TO CONTINUE OVERNIGHT ACROSS PARTS OF SWRN NEB. AN UPPER LEVEL LOW DEVELOPING ACROSS ERN NM/NW TEXAS TONIGHT IS EXPECTED TO SHOOT A BAND OF WARM AIR ADVECTION DRIVEN SHOWERS NORTHWARD INTO SRN NEB. THE MODELS INDICATE THIS BAND OF SHOWERS WILL FALL APART FAIRLY QUICKLY AS IT MOVES NORTH. A MORE SUBSTANTIAL BAND OF SHOWERS SHOULD DEVELOP TUESDAY NIGHT WHICH IS PROGGED TO SWEEP INTO PARTS OF WRN AND NCNTL NEB PRODUCING AROUND 1/2 TO 3/4 OF AN INCH OF RAIN ON WEDNESDAY. THE GFS APPEARS TO SUFFERING QPF FEEDBACK PROBLEMS. TIME HEIGHTS SHOW 20 UBARS OF LIFT EXTENDING UPWARD TO OVER 500 MB AND THE QPF LOOKS OVERDONE. A 4-WAY BLEND OF NAM...GEM...ECM AND GFS WAS USED AS A BASIS FOR QPF AND POPS WHICH SUGGESTED DEFINITE RAIN CHANCES WEDNESDAY. THE STORM SYSTEM SHOULD CLEAR THE FCST AREA LATE WEDNESDAY NIGHT WITH CLEARING SKIES ON THURSDAY. THEREAFTER A PERIOD OF WARM AIR ADVECTION DEVELOPS FRIDAY AHEAD OF A DEEP UPPER LEVEL TROF SITUATED ACROSS THE WRN U.S.. STRATUS AND SHOWERS ARE POSSIBLE EARLY FRIDAY MORNING. A STRONG DISTURBANCE WILL LIFT THROUGH THE NRN HIGH PLAINS FRIDAY AFTN AND FRIDAY NIGHT. TSTMS ARE POSSIBLE ACROSS NORTHERN PORTIONS OF THE FCST AREA AS THIS DISTURBANCE LIFT THROUGH THE PLAINS. A PV15 ANOMALY WILL BE OPERATING IN TANDEM WITH THE DISTURBANCE AND A DRYLINE BULGE SHOULD DEVELOP FOLLOWED BY A STRONG PACIFIC COLD FRONT. HIGH PRESSURE AND COOL WEATHER IS EXPECTED SATURDAY THROUGH MONDAY WITH HIGHS IN THE 50S TO LOWER 60S. AVIATION... WIND SPEEDS ARE EXPECTED TO DECREASE THIS EVENING...HOWEVER GUSTS ARE EXPECTED TO STAY AT OR ABOVE 25KTS THROUGH THE OVERNIGHT HOURS AND MUCH OF TUESDAY MORNING. LOCATIONS ACROSS SOUTHWEST INTO CENTRAL NEBRASKA /FROM KOGA TO KTIF TO KONL/ WILL SEE THE HIGHER WINDS PERSIST THE LONGEST...WITH GUSTS OVER 30KTS. MODELS INDICATE LOW LEVEL MOISTURE WILL INCREASE THIS EVENING LEADING TO FURTHER DEVELOPMENT OF STRATUS AND MVFR CEILINGS. THERE ARE MIXED SIGNALS ON THE HEIGHT OF THIS CLOUD LAYER. SO ALTHOUGH FAIRLY CONFIDENT ON STRATUS ACROSS THE AREA...DO HAVE A CONSIDERATE AMOUNT OF UNCERTAINTY ON THE CLOUD HEIGHT. NAM WOULD SAY IFR CEILINGS WHILE OTHER SOLUTIONS WOULD ACTUALLY RAISE THE CEILINGS TO ABOUT 5K FEET. AT THIS TIME...KEPT A STABLE FORECAST WITH CEILINGS AT BOTH KVTN AND KLBF AT 2500 FT THROUGH TUESDAY MORNING. && .LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ TUESDAY FOR NEZ057-058-069-070. WIND ADVISORY UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR NEZ005- 006-008-009-024>027-036>038-059. HIGH WIND WARNING UNTIL 6 PM MDT THIS EVENING FOR NEZ004-022-023- 056-094. WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR NEZ004-094. WIND ADVISORY UNTIL 6 AM MDT TUESDAY FOR NEZ056. WIND ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR NEZ022-023. WIND ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY FOR NEZ035- 071. && $$ SHORT TERM/EXTENDED...CDC AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
346 PM CDT MON APR 2 2012 .SHORT TERM...TONIGHT AND TUESDAY. MAIN FORECAST CONCERN WILL BE CHANCE FOR SHOWERS AND THUNDERSTORMS. SURFACE ANALYSIS AND SURFACE OBSERVATIONS INDICATE A COLD FRONT ACROSS THE EASTERN PART OF THE FORECAST AREA THIS AFTERNOON. AHEAD OF THE COLD FRONT TEMPERATURES HAVE JUMPED AND ARE QUITE WARM. COOLER TEMPERATURES ARE BEHIND THE FRONT. SATELLITE SHOWS SOME STRATUS ACROSS THE FAR NORTHERN PART OF THE FORECAST AREA. THIS WAS SPREADING FURTHER SOUTH THIS MORNING...BUT HAS HELD OFF DURING THE AFTERNOON. WINDS HAVE FINALLY STARTED TO INCREASE TO THE WEST AND WILL CONTINUE TO INCREASE THIS AFTERNOON FOR THE FAR WEST. WILL LEAVE THE WIND ADVISORY AS IS. THE POSITION OF THE FRONT IS KEY THIS AFTERNOON FOR THUNDERSTORM DEVELOPMENT. MODELS HAVE THUNDERSTORMS DEVELOPING ALONG THE FRONT DURING THE LATE AFTERNOON AND EARLY EVENING. WITH THE CURRENT LOCATION OF THE FRONT EXPECT THUNDERSTORMS TO BE IN THE SOUTHEAST PART OF THE FORECAST AREA. THE HRRR KEEPS THE PRECIPITATION IN THE FAR SOUTHEAST THROUGH THE EVENING WHILE THE NAM AND GFS HAVE IT A BIT FURTHER TO THE NORTHWEST. THE BEST MUCAPES ARE IN THE FAR SOUTHEAST PART OF THE FORECAST AREA WITH THE OVER 1000J/KG CAPES FAR IN THE SOUTHEASTERN PART OF THE FORECAST AREA. LATER THIS EVENING AND OVERNIGHT AN UPPER LEVEL LOW DEVELOPING ON THE SOUTHERN HIGH PLAINS STARTS TO DRIFT TO THE NORTH AND PUSHES PRECIPITATION TO THE NORTH BEHIND THE FRONT. MOST OF THE PRECIPITATION SHOULD BE IN THE SOUTHERN PART OF THE FORECAST AREA. THE UPPER LEVEL LOW CONTINUES TO DRIFT THROUGH THE SOUTHERN HIGH PLAINS ON TUESDAY AND THE CHANCE FOR SHOWERS CONTINUES MAINLY IN THE SOUTH/SOUTHWEST. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY. PRIMARY FORECAST CONCERN LIES WITH PRECIPITATION CHANCES EARLY ON IN THE PERIOD. LOOKING AT THE TIME FRAME STARTING TUESDAY NIGHT AND CONTINUING THROUGH WEDNESDAY NIGHT...THE MAIN STORY LIES WITH THE IMPACT ACROSS THE REGION FROM A PASSING UPPER LEVEL LOW PRESSURE SYSTEM AND ASSOCIATED PRECIPITATION CHANCES. LATEST MODELS RUNS ARE IN PRETTY GOOD AGREEMENT AT THE START OF THE PERIOD...SHOWING THE LOW CENTERED OVER THE PANHANDLES OF TX/OK...BUT MORE VARIANCES START TO SHOW UP THROUGH THE OVERNIGHT HOURS AND INTO WEDNESDAY. THE SYSTEM DOESNT MAKE A WHOLE LOT OF EASTWARD PROGRESS...WITH A RIDGE AXIS TO THE EAST EXTENDING FROM THE GULF COAST REGION UP INTO THE ERN DAKOTAS...AND BY WEDNESDAY EVENING LOOKS TO RANGE IN LOCATION FROM SC KS TO WRN OK. INCREASED LIFT OUT AHEAD OF THE LOW PRESSURE SYSTEM WILL HELP WITH THE NORTHWARD SPREAD OF PRECIPITATION FROM THE SRN PLAINS INTO THE CWA TUESDAY EVENING/OVERNIGHT...WHICH WILL CONTINUE ON INTO THE DAYTIME HOURS ON WEDNESDAY AS INCREASED LOW/MID LEVEL FRONTOGENETICAL ON THE NORTHERN SIDE OF THE LOW SHIFTS INTO THE CWA. DECIDED TO INSERT A MENTION OF ISOLATED THUNDER WED EVENING...WITH SOME OF THE MODELS/SREF PROBS SHOWING THE POTENTIAL LINGERING AROUND THE SOUTHEASTERN CORNER OF THE CWA. EXPECTING PLENTY OF CLOUD COVER AND GENERALLY N/NE WINDS AS THE MAIN SFC LOW SLIDES TO THE SOUTH OF THE CWA...WITH HIGHS TOPPING OUT IN THE LOW/MID 50S. MODELS ARE A LITTLE SLOWER THURSDAY EVENING/NIGHT PUSHING PRECIPITATION CHANCES EAST OF THE CWA AS THE UPPER LEVEL LOW MAKES ITS WAY TOWARD THE MO RIVER...AND PUSHED POPS BACK WEST TO INCLUDE ALL COUNTIES. UPPER LEVEL SHORTWAVE RIDGING BUILDING INTO THE PLAINS IN THE WAKE OF THIS LATEST SYSTEM IS EXPECTED TO KEEP THURSDAY AND THURSDAY NIGHT DRY. SEE A SLIGHT BUMP IN HIGHS BUT TEMPS REMAIN ON THE RELATIVELY COOL SIDE /COMPARED TO THE LAST FEW DAYS...BUT STILL NEAR OR ABOVE AVG/...WITH THE CWA REMAINING ON THE WRN/SRN FRINGE OF SFC HIGH PRESSURE OVER THE WRN GREAT LAKES...AND AM EXPECTING LOWER 60S. NEXT CHANCE FOR PRECIPITATION IS EXPECTED TO COME TO WESTERN PORTIONS OF THE CWA DURING THE DAY ON FRIDAY AND EXPAND FURTHER EAST FRIDAY NIGHT...AS ANOTHER SHORTWAVE TROUGH AXIS LOOKS TO SWING THROUGH THE NORTHERN/CENTRAL PLAINS. MODELS VARY SOME THROUGH THIS TIMEFRAME...WITH THE GFS SHOWING THIS ENERGY ASSOCIATED WITH AN ELONGATED LOW OVER WRN/CENTRAL CANADA...WHILE THE EC SHOWS ANY LOW LOCATED OFF THE PAC NW COAST. KEPT THE HIGHER POPS ACROSS THE NORTH WHERE THERE IS BETTER AGREEMENT BETWEEN THE MODELS...BUT POPS GO ALL THE WAY SOUTH TROUGH THE CWA WITH THE GFS CONTINUING TO SHOW MORE COVERAGE. THE MAIN INSTABILITY AXIS LOOKS TO SET UP JUST WEST OF THE CWA DURING THE DAY...AND PUSH THROUGH DURING THE OVERNIGHT HOURS...WITH MUCAPE VALUES UPWARDS OF 7-800 J/KG...SO THREAT OF SOME STRONG STORMS WILL REMAIN...BUT WILL CONTINUE TO KEEP AN EYE ON THE POTENTIAL FOR SEVERE STORMS. KEPT THE FORECAST FOR THE UPCOMING WEEKEND AND INTO MONDAY DRY...THOUGH THE GFS TRIES TO LINGER SOME POPS IN THE EAST EARLY ON SAT MORNING. AN ACCOMPANYING SURFACE COLD FRONT IS EXPECTED TO BE ON ITS WAY THROUGH THE CWA SATURDAY MORNING...BUT MODELS DO VARY SOME ON THE TIMING. EC IS ON THE QUICKER SIDE...WITH THE FRONT CLEARING THE CWA SAT MORNING...WHILE THE GFS WOULD BE MORE INTO THE AFTERNOON. LOOKS TO BE BREEZY DAY ON SATURDAY...WITH NORTHWEST WINDS PICKING UP BEHIND THE FRONT. MORE ZONAL/NORTHWESTERLY FLOW SETS UP IN THE UPPER LEVELS FOR SUN/MON WITH A RIDGE SET UP OVER THE SRN/SWRN CONUS...WITH NO NOTABLE SYSTEM LOOKING TO PASS THROUGH. BEHIND THE SFC FRONT...HIGH PRESSURE BUILDS IN AND IS THE DOMINANT FEATURE ON SUNDAY...BRINGING A PLEASANT WITH LIGHT WINDS AND HIGHS TOPPING OUT IN THE LOWER/MID 60S. MONDAY COULD SEE AN INCREASE IN WINDS DEPENDING ON THE MODEL...BUT STILL EXPECTING ANOTHER NICE DAY WITH HIGHS SIMILAR TO SUNDAY. && .PREV DISCUSSION... /ISSUED 1234 PM CDT MON APR 2 2012/ AVIATION...18Z TAF. A COLD FRONT IS NEARLY ON TOP OF THE KGRI TERMINAL AT THIS TIME AND WILL CONTINUE TO MOVE TO THE EAST. THIS WILL TURN THE WINDS TO THE NORTH AND INCREASE THEM THROUGH THE AFTERNOON AND EVENING. THE WINDS WILL WEAKEN THIS EVENING A LITTLE...BUT EXPECT THAT THEY WILL CONTINUE THROUGH THE NIGHT. THERE IS A LITTLE CHANCE THERE WILL BE SOME SHOWERS AROUND THE AREA BUT DO NOT EXPECT A LOT. THERE WILL BE SOME MVFR CEILINGS LATE TONIGHT INTO TUESDAY MORNING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY UNTIL 11 PM CDT THIS EVENING FOR NEZ039-046-060- 061-072-073-082-083. KS...WIND ADVISORY UNTIL 11 PM CDT THIS EVENING FOR KSZ005-017. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
336 PM CDT MON APR 2 2012 .DISCUSSION... THE SHORT TERM CONCERNS WILL BE THE POTENTIAL FOR THUNDERSTORMS AND SEVERE WEATHER AND IF A WIND ADVISORY WILL BE NEEDED. AT 20Z...THE COLD FRONT HAD FINALLY MADE IT INTO NORFOLK AND THEIR TEMPERATURES WERE BEGINNING TO FALL. AHEAD OF THE FRONT...TEMPERATURES TOPPED OUT IN THE 80S TO LOWER 90S. THE LOW CLOUDS HAD MADE IT INTO THE THE ONEILL AREA AND TEMPERATURES WERE ONLY IN THE 50S. WINDS IN THE WEST CENTRAL PART OF NEBRASKA WERE QUITE STRONG WITH GUSTS IN THE 40 TO 50 MPH IN SPOTS. TONIGHT...THE SURFACE COLD FRONT WILL BE MOVING ACROSS THE REST OF EASTERN NEBRASKA AND SOUTHWEST IOWA. THE HIGHER UPPER 50S AND LOWER 60S DEGREE DEWPOINTS AT 20Z EXTENDED FROM BEATRICE TO OMAHA AND THESE WILL SHIFT EASTWARD WITH TIME. THE 4KM WRF HAD THUNDERSTORMS ALONG THE FRONT...WHILE THE 18Z NAM WAS DRY...THE LATEST RUC HAD SOME STORMS DEVELOPING TOWARD FAIRBURY AND THE GFS HAD AN AREA SIMILAR TO THE 4KM WRF...BUT SHIFTED FARTHER SOUTHEAST AND MAINLY ALONG AND SOUTH OF I80. THERE IS THE POTENTIAL FOR THUNDERSTORMS THIS EVENING AHEAD OF AND ALONG THE FRONT AND WILL MAINTAIN ISOLATED TO SCATTERED THUNDERSTORM CHANCES MAINLY ALONG AND SOUTH OF I80. THE ATMOSPHERE HAS GOOD INSTABILITY AND STEEP LAPSE RATES TO WORK WITH...HOWEVER THE SHEAR PARAMETERS DO NOT APPEAR AS FAVORABLE IN THIS AREA. SPC HAS A SLIGHT RISK AND THE SLIGHT RISK APPEARS WARRANTED BASED ON CONDITIONAL FACTORS AS SHOULD THUNDERSTORMS GET GOING THEY COULD CONTAIN SOME HAIL AND DAMAGING WINDS. BEHIND THE FRONT...ESPECIALLY ACROSS NORTHEAST NEBRASKA THE WINDS WILL BE STRONG. AT THIS TIME WILL HAVE WINDY CONDITIONS AT 20 TO 30 MPH WITH GUSTS TO 45...BUT HAVE NOT GONE WITH A WIND ADVISORY AT THIS TIME. BEHIND THE FRONT...WITH THE LOW CLOUDS THERE MAY BE SOME SHOWERS IN NORTHEAST NEBRASKA AND SOME OF THESE MAY LINGER INTO TUESDAY. THE SOUTHERN ENERGY WITH THIS STORM SYSTEM WILL CLOSE OFF AND LIFT NORTH. THIS WILL RETURN THE CHANCE FOR SHOWERS AND THUNDERSTORMS TUESDAY NIGHT AND WEDNESDAY AND WEDNESDAY NIGHT AND THEN MOVE OUT THURSDAY. THURSDAY NIGHT THROUGH MONDAY....THE STORM SYSTEM THAT WILL AFFECT US FOR MUCH OF THE WEEK WILL BE OVER SOUTHERN MISSOURI AT THE START OF THE EXTENDED WITH DRY CONDITIONS...SOUTHEAST BREEZES AND COMFORTABLE TEMPERATURES IN THE 60S FRIDAY. FRIDAY NIGHT...THE TROF OVER THE PACIFIC NORTHWEST WILL PUSH FAR ENOUGH EASTWARD TO PUSH TO FRONT INTO PARTS OF EASTERN NEBRASKA BY 12Z SATURDAY. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AHEAD OF AND ALONG THE COLD FRONT FRIDAY NIGHT AND SATURDAY. AS THIS SYSTEM MOVES OUT OF THE AREA...MID LEVEL RIDGING BUILDS IN AND DRY WEATHER AND MORE SEASONABLE WEATHER IS FORECAST FOR SATURDAY AND SUNDAY. && .AVIATION... 18Z TAFS FOR KOFK...KOMA AND KLNK. COLD FRONT WILL BE CROSSING ERN NEBRASKA LATER THIS AFTERNOON THROUGH EARLY EVENING WITH SOME RISK OF CONVECTION ALONG IT...ESPECIALLY SW OF KLNK. ANY ACTIVITY THAT DEVELOPS...HOWEVER...WILL MOVE NORTHEAST TOWARD KLNK AND KOMA. DID NOT MENTION TSTM IN 18Z TAF...ALTHOUGH SOME POP/TEMPO GROUP WITH CB WAS INCLUDED. MVFR CIGS SHOULD SPREAD IN BEHIND FRONT...ALTHOUGH DAYTIME HEATING COULD RESTRICT THEIR SE MOVEMENT. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ ZAPOTOCNY/CHERMOK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1234 PM CDT MON APR 2 2012 .AVIATION...18Z TAF. A COLD FRONT IS NEARLY ON TOP OF THE KGRI TERMINAL AT THIS TIME AND WILL CONTINUE TO MOVE TO THE EAST. THIS WILL TURN THE WINDS TO THE NORTH AND INCREASE THEM THROUGH THE AFTERNOON AND EVENING. THE WINDS WILL WEAKEN THIS EVENING A LITTLE...BUT EXPECT THAT THEY WILL CONTINUE THROUGH THE NIGHT. THERE IS A LITTLE CHANCE THERE WILL BE SOME SHOWERS AROUND THE AREA BUT DO NOT EXPECT A LOT. THERE WILL BE SOME MVFR CEILINGS LATE TONIGHT INTO TUESDAY MORNING. && .PREV DISCUSSION... /ISSUED 419 AM CDT MON APR 2 2012/ SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. THE PATTERN ALOFT REVEALED AN UPPER TROUGH IN THE ROCKIES WITH THE MID/UPPER CIRCULATION CLOSING OFF NEAR THE FOUR CORNERS REGION. AHEAD OF THIS SYSTEM...SOUTHWEST FLOW WAS IN PLACE ACROSS THE CENTRAL PLAINS WHILE UPPER RIDGE HAD SHIFTED EAST OF THE MISSOURI RIVER. AT THE SURFACE...LOW PRESSURE WAS CENTERED IN FAR NORTHWEST KANSAS...WITH COOL FRONTAL BOUNDARY EXTENDING FROM VTN TO KSNY...AND DRYLINE EXTENDED ACROSS EASTERN CO. PRESSURE RISES BEHIND THE FRONT BEHIND THE FRONT AVERAGED 3-5MB. THERE HAVE BEEN SOME DISTINCT CHANGES IN FRONTAL TIMING...WINDS AND POTENTIAL FOR CONVECTION TODAY. SURFACE FRONT STILL ENTERS OUR WESTERN CWA AROUND 12Z...BUT SLOWS AND STALLS ACROSS OUR SOUTHEAST CWA AROUND MID AFTERNOON. INSTABILITY PROGS INDICATE MUCAPE AROUND 1500 J/KG IN OUR FAR SOUTHEAST CWA FOR A FEW HOURS WITH HIGHER CAPE AXIS FARTHER SOUTHEAST AHEAD OF THE BOUNDARY...AND A BRIEF PERIOD OF EFFECTIVE SHEAR OF 30 TO 40KTS RESIDE ALONG THE BOUNDARY...GENERALLY BETWEEN 21 AND 00Z. AS THE BOUNDARY STALLS IN OUR SOUTHEAST...CAN NO LONGER RULE OUT CONVECTIVE POTENTIAL AND A WINDOW OF OPPORTUNITY FOR SEVERE WEATHER WITH STORMS CAPABLE OF PRODUCING LARGE HAIL/DAMAGING WINDS. 4KM SPC WRF DEVELOPS CONVECTION ACROSS OUR SOUTHERN CWA IN VCNTY OF BOUNDARY AND WITH CONTINUING TRENDS OF FRONT SLOWING DOWN...HAVE RETURNED TSTMS TO FORECAST. ALSO DUE TO SLOWER FRONTAL PROGRESSION TODAY...THIS ALSO HAS AN IMPACT ON STRENGTH OF WINDS ACROSS OUR REGION. THE CORRIDOR OF STRONGEST PRESSURE RISES THIS MORNING SLIDE SOUTH FROM WESTERN NEBRASKA INTO WESTERN KANSAS AND SFC GRADIENT REMAINS TIGHTEST ACROSS THE WESTERN HALF OF NEBRASKA INTO NW KANSAS. FRONT DOES NOT REACH OUR EASTERN AND SOUTHEAST COUNTIES UNTIL THIS AFTERNOON OR EARLY EVENING AND WINDS WILL INITIALLY BE GUSTY OUT OF THE SOUTH BUT NOT AT WIND ADVISORY CRITERIA. AS FRONT PUSHES THRU OUR SOUTHEAST CWA IN THE EVENING...A SECONDARY SURGE OF PRESSURE RISES AND CORRIDOR OF 40KT MID LEVEL WINDS MOVE THRU BEGINNING GENERALLY AROUND 00Z AND LINGERING/SPREADING SOUTHWARD UNTIL AROUND MIDNIGHT. WHAT THIS MEANS IS THAT REACHING WIND ADVISORY CRITERIA ESPECIALLY IN OUR EAST/SOUTHEAST IS LOOKING LESS LIKELY UNTIL POTENTIALLY CLOSER TO 00Z WITH SECONDARY SURGE OF FRONT/PRESSURE RISES. OUR WESTERN COUNTIES WILL STILL STAND A BETTER CHC FOR WIND ADVISORY CRITERIA BUT IN ESSENCE MAY BE MORE OF A BUFFER TO THE EVEN HIGHER WINDS ACROSS WESTERN NEBRASKA AND KANSAS. FOR HEADLINE...OPTIONS ARE TO EITHER CANCEL EASTERN/SOUTHEAST PORTION OR HOLD OFF ON TIMING UNTIL THE EVENING HOURS. HAVE OPTED TO REMOVE WIND ADVISORY IN THE EAST AND MAINTAIN A BUFFER IN THE WEST. LATEST HRRR SUGGESTS STRONGER WINDS COULD HOLD OFF EVEN IN OUR WEST UNTIL AFTN WHILE THE INITIALLY STRONGER WINDS WILL BE FM THE SOUTH IN OUR EASTERN COUNTIES. OTHER CHANGE IN MODELS...WHICH HAS BEEN A GENERAL TREND AS WELL...IS THE FARTHER NORTH TRACK OF THE UPPER LOW AS IT LIFTS FM THE TX/OK PANHANDLES TUESDAY. GENERAL CONSENSUS IS THAT LOW WILL LIFT AND TRACK ACROSS KANSAS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...AND THE ECMWF REMAINS SLOWER WITH PROGRESSION WHICH COULD POTENTIALLY LINGER PCPN CHCS BEYOND WEDNESDAY NIGHT. LATEST TRACK PROMISES TO PROVIDE A DECENT RAIN EVENT ACROSS THE CENTRAL PLAINS MAINLY FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. POPS HAVE BEEN TRENDED UPWARD INTO LIKELY CATEGORY...AND SOME DECENT SPRING RAINFALL TOTALS ARE POSSIBLE WITH PRECIPITABLE WATER VALUES AVERAGING 0.75 TO JUST OVER AN INCH. HAVE KEPT THUNDER WORDING OUT AS INSTABILITY PARAMETERS ARE RATHER MEAGER BUT WOULD NOT BE SURPRISED TO SEE AN OUTSIDE LIGHTNING STRIKE HERE OR THERE...ESPECIALLY IN OUR SOUTHEAST WHERE MUCAPES ARE NOT ZERO...JUST RATHER LOW. LONG TERM...THURSDAY THROUGH SUNDAY. PRIMARY FOCUS THROUGH THIS 4-DAY PERIOD IS THE RISK FOR THUNDERSTORMS IN THE FRI-SAT TIME FRAME...BUT MAINLY CENTERED FRIDAY NIGHT AND NOT EVEN IN LIKELY POP TERRITORY YET. ALTHOUGH NOT NEARLY AS WARM AS LATELY...HIGH TEMPS THROUGH THIS PERIOD SHOULD NONETHELESS AVERAGE SOLIDLY IN THE 60S MOST AREAS...OR STILL SLIGHTLY ABOVE NORMAL FOR EARLY APRIL. AS FOR OVERNIGHT LOWS...WILL HAVE TO KEEP AN EYE OUT AS EARLY AS SAT NIGHT FOR POSSIBLE FROST POTENTIAL. STARTING OFF THURSDAY...00Z ECMWF/GFS RUNS ARE IN DECENT AGREEMENT DEPICTING A DEPARTING MID LEVEL CLOSED LOW GENERALLY WANDERING SOMEWHERE OVER MO. AT THE SAME TIME...A FAIRLY EXPANSIVE UPSTREAM TROUGH WILL BE CENTERED OVER THE WESTERN 1/3 OF THE CONUS. AT LEAST FOR NOW...LEFT THURSDAY DAYTIME DRY...ALTHOUGH THERE ARE SOME HINTS THAT AT LEAST SOME EASTERN AREAS COULD STILL BE PRONE TO SOME LINGERING LIGHT RAIN SHOWERS. FOR NOW THOUGH WILL STAY THE COURSE AND REMAIN TRUE TO THE DRY FCST INITIALIZED BY THE ALLBLEND MODEL PROCEDURE. FOR HIGH TEMPS...NUDGED DOWN A FEW DEGREES MOST AREAS GIVEN PREDOMINANT EASTERLY LOW LEVEL FLOW...WITH THE MAJORITY OF THE CWA IN THE 62-65 RANGE. KEPT THURS NIGHT DRY AS PRIMARY LOW LEVEL JET AXIS AND RESULTANT FOCUS FOR POSSIBLE CONVECTION APPEARS TO REMAIN AT LEAST SLIGHTLY WEST OF THE CWA. FRIDAY/FRIDAY NIGHT...THIS 24 HOUR PERIOD APPEARS TO FEATURE THE PRIMARY RISK FOR THUNDERSTORMS IN THE LONG TERM...ESPECIALLY ON FRIDAY NIGHT. DURING THE DAY...SOUTHEAST WINDS WILL PICK UP INTO BREEZY TERRITORY AS PRESSURES FALL OVER THE HIGH PLAINS...BUT AT THIS TIME SPEEDS LOOK TO REMAIN BELOW ADVISORY CRITERIA. ALLBLEND PROCEDURE INTRODUCED A SLIGHT CHANCE OF STORMS DURING THE DAY ACROSS WESTERN COUNTIES...AND OPTED TO RUN WITH IT...ALTHOUGH CONFIDENCE IS RATHER LOW GIVEN EXPECTATION OF WEAK FORCING AND SOME CAPPING...DESPITE THE ECMWF AND GFS BOTH ADVERTISING A NARROW...FAIRLY WEAK INSTABILITY AXIS SETTING UP NEAR THE SOUTHERN/WESTERN EDGES OF THE CWA THROUGH THE DAY. IN ALL HONESTY THOUGH...THESE SLIGHT CHANCES DURING THE DAY ARE ALREADY ON SOMEWHAT SHAKY GROUND RIGHT OUT OF THE GATE. BETTER CHANCES...ALTHOUGH STILL ONLY IN THE 30-40 PERCENT RANGE AT THIS TIME...ARRIVE FRIDAY NIGHT AS FORCING FROM THE LEADING SHORTWAVE EMANATING FROM THE WESTERN CONUS TROUGH SWINGS ALONG A TRACK FROM WY/NORTHERN CO ACROSS WESTERN NE INTO SD. ALTHOUGH THIS TAKES THE BULK OF THE LARGE SCALE FORCING NORTH OF THE CWA...BOTH MODELS GENERATE QPF...WITH THE GFS ADVERTISING A SURGE OF INSTABILITY DURING THE NIGHT...WITH MUCAPE VALUES CLIMBING TO AROUND 1500 J/KG IN THE PRESENCE OF AT LEAST 40KT OF DEEP LAYER SHEAR. FOR NOW WILL INTRODUCE A STRONG STORM MENTION IN THE HWO...BUT WILL NEED TO KEEP A CLOSE EYE ON SEVERE POTENTIAL OVER NEXT FEW DAYS. SATURDAY...MID RANGE MODELS CONTINUE TO AGREE ON THE LARGER SCALE PATTERN...WITH THE MAIN MID LEVEL WAVE CROSSING THE DAKOTAS TOWARD MN...WHILE A SURFACE COLD FRONT TRACKS ACROSS THE CWA AND USHERS IN DRIER/MORE STABLE AIR. ALLBLEND MODEL KEPT SOME TOKEN SLIGHT POPS ACROSS FAR NORTHEAST AND SOUTHEAST PORTIONS OF THE CWA DURING THE DAY...AND WILL LET IT RIDE FOR NOW. SAT NIGHT/SUNDAY...CONFIDENCE IS RATHER HIGH AT THIS TIME RANGE THAT DRY CONDITIONS WILL PREVAIL IN THE WAKE OF THE DEPARTING WAVE...ALTHOUGH MODELS START TO DIVERGE ALOFT WITH THE ECMWF ADVERTISING BROAD WEST-NORTHWEST FLOW WHILE THE GFS IS MORE WEST- SOUTHWEST. DOWN LOW HOWEVER...THERE IS A DECENT SIGNAL FOR HIGH PRESSURE TO RULE THE SCENE ON SATURDAY NIGHT WITH FAIRLY LIGHT WINDS. ALTHOUGH CURRENT FORECAST KEEPS LOWS UP IN THE UPPER 30S- LOW 40S FOR MOST OF THE CWA...WILL HAVE TO MONITOR FOR THE POTENTIAL FOR A MORE WIDESPREAD LOW-MID 30S...WHICH COULD AT LEAST BRING SOME FROST POTENTIAL INTO PLAY. CERTAINLY TOO EARLY AT THIS TIME TO FORMALLY PUT IT IN THE FORECAST. PEEKING AHEAD A BIT INTO THE WEEK OF APRIL 9TH...COULD BE A FEW MORE RISKS FOR OVERNIGHT TEMPS DROPPING DOWN INTO AT LEAST THE FROST POSSIBILITY RANGE...WHICH IS RIGHT IN LINE WITH CLIMATOLOGY FOR MID APRIL. AVIATION...06Z KGRI TAF. WIND WILL BE THE BIGGEST FACTOR FOR THIS FORECAST. EAST TO SOUTHEAST WIND WILL PREVAIL OVERNIGHT AND WILL CONTINUE TO BE A BIT ON THE BREEZY SIDE. A COLD FRONT WILL MOVE IN TOWARD MID-MORNING AND WILL SWITCH WIND DIRECTION TO THE NORTH NORTHWEST AND WILL BECOME VERY GUSTY FROM STRONG HEIGHT RISES...ESPECIALLY TOWARD EVENING. ANY PRECIPITATION SHOULD HOLD OFF TO THE SOUTH AND WELL AFTER THE FRONT PASSES THROUGH. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY UNTIL 11 PM CDT THIS EVENING FOR NEZ061-073-083. WIND ADVISORY UNTIL 11 PM CDT THIS EVENING FOR NEZ039-046-060- 072-082. KS...WIND ADVISORY UNTIL 11 PM CDT THIS EVENING FOR KSZ005-017. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1223 PM CDT MON APR 2 2012 .AVIATION... 18Z TAFS FOR KOFK...KOMA AND KLNK. COLD FRONT WILL BE CROSSING ERN NEBRASKA LATER THIS AFTERNOON THROUGH EARLY EVENING WITH SOME RISK OF CONVECTION ALONG IT...ESPECIALLY SW OF KLNK. ANY ACTIVITY THAT DEVELOPS...HOWEVER...WILL MOVE NORTHEAST TOWARD KLNK AND KOMA. DID NOT MENTION TSTM IN 18Z TAF...ALTHOUGH SOME POP/TEMPO GROUP WITH CB WAS INCLUDED. MVFR CIGS SHOULD SPREAD IN BEHIND FRONT...ALTHOUGH DAYTIME HEATING COULD RESTRICT THEIR SE MOVEMENT. CHERMOK && .PREV DISCUSSION... /ISSUED 1048 AM CDT MON APR 2 2012/ UPDATE... UPDATED TO INCREASE HIGHS AHEAD OF FRONT SOME AREAS AND TO REDUCE/DROP PRECIP CHCS THIS AFTERNOON. DISCUSSION... MORNING KOAX SOUNDING SHOWED VERY WARM TEMPERATURE LAYER CENTERED ON H85 WITH WELL MIXED CAP ABOVE. QUESTION IS WHETHER FRONT CAN BREAK CAP OVER NEBRASKA AND SOME CONFLICTING INFORMATION FROM MODELS. LATEST RUC SOUNDING DID TO SOME DEGREE...EVEN IN ECNTRL SECTIONS...WHILE 00Z GFS WAS MORE RESTRICTED TO SWRN FORECAST AREA. SHORTER RANGE QPF FORECASTS FROM RUC/HRRR DEVELOPED NO PRECIP OVER FORECAST AREA THROUGH 00Z WHILE LAST EVENINGS 4KM WRF DID AS DID THE 06Z NAM/GFS. HOWEVER...12Z NAM REFRAINS FROM SPREADING PRECIP INTO SRN ZONES UNTIL THIS EVENING. BASED ON MORNING SOUNDING...FELT ANY CONVECTION THAT MAKES IT INTO FORECAST AREA WILL EITHER DEVELOP LATE IN THE AFTN ON FRONT OVER SWRN ZONES OR SW OF NEBRASKA AND THEN ATTEMPT TO BUILD INTO SERN ZONES THIS EVENING. THUS POPS WERE DROPPED MUCH OF THE AREA N THROUGH E OF OMA ALONG WITH FAR SERN NEBRASKA THIS AFTN AND TRIMMED BACK ALL BUT SEVERAL SW COUNTIES FM OMAHA SWWD. ALSO RAISED MAX TEMPS A BIT IN ERN ZONES BASED ON MORNING SOUNDING AND BOOSTED WINDS A LITTLE BOTH AHEAD OF AND BEHIND FRONT. CHERMOK PREV DISCUSSION... /ISSUED 631 AM CDT MON APR 2 2012/ DISCUSSION... WV IMAGERY SHOWING FEATURE OF CONCERN...DEEP LONGWAVE TROF...OVER THE ROCKIES SLOWLY MIGRATING TO THE EAST THIS MORNING WHILE SFC LOW PRESSURE WAS CENTERED IN NERN CO. MODELS IN DECENT AGREEMENT THAT THE LONGWAVE TROF WILL FORM INTO A CLOSED LOW OVER THE SRN PLAINS AND BECOME CUT OFF BY EARLY TUESDAY MORNING...THEN EVENTUALLY LIFTING ACROSS THE CENTRAL PLAINS EARLY THURSDAY. FOR TODAY...ANTICIPATED COLD FRONT WILL SWEEP INTO THE CENTRAL PLAINS AS CO SFC LOW TREKS TOWARD THE MID MS VLY. VARIOUS TIME-SERIES PROGS PUT THE FRONT THRU THE METRO-AREA SOMETIME EARLY THIS EVENING. PW VALUES AROUND 1.25" AND KI 35-40 INDICATE ENVIRONMENT WILL BE MOISTURE RICH. THAT...IN COMBINATION WITH FAVORABLE MUCAPE/EFF SRH/EFF BULK WIND DIFFERENCE PARAMETERS SUGGEST LATE AFTN/EARLY EVENING SEVERE STORM DEVELOPMENT A DISTINCT POSSIBILITY...PARTICULARLY AREAS SOUTH OF I-80. FORTUNATELY...APPEARS THAT TOR THREAT WILL BE MINIMAL DUE TO ML LFC PROGGED AOA 2200M. PCPN CHANCES CONTINUE THEN TUESDAY THROUGH THURSDAY MAINLY SOUTH AS AREA FALLS UNDER INFLUENCE OF CLOSED LOW DYNAMICS TREKKING ACROSS KS. OTHERWISE THIS COOLER AIRMASS FILTERING IN THIS WEEK WILL BRING A NOTICEABLE CHANGE. NEVERTHELESS...NEAR NORMAL MAX TEMPS WILL BE QUITE ATTAINABLE. DEE && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1048 AM CDT MON APR 2 2012 .UPDATE... UPDATED TO INCREASE HIGHS AHEAD OF FRONT SOME AREAS AND TO REDUCE/DROP PRECIP CHCS THIS AFTERNOON. && .DISCUSSION... MORNING KOAX SOUNDING SHOWED VERY WARM TEMPERATURE LAYER CENTERED ON H85 WITH WELL MIXED CAP ABOVE. QUESTION IS WHETHER FRONT CAN BREAK CAP OVER NEBRASKA AND SOME CONFLICTING INFORMATION FROM MODELS. LATEST RUC SOUNDING DID TO SOME DEGREE...EVEN IN ECNTRL SECTIONS...WHILE 00Z GFS WAS MORE RESTRICTED TO SWRN FORECAST AREA. SHORTER RANGE QPF FORECASTS FROM RUC/HRRR DEVELOPED NO PRECIP OVER FORECAST AREA THROUGH 00Z WHILE LAST EVENINGS 4KM WRF DID AS DID THE 06Z NAM/GFS. HOWEVER...12Z NAM REFRAINS FROM SPREADING PRECIP INTO SRN ZONES UNTIL THIS EVENING. BASED ON MORNING SOUNDING...FELT ANY CONVECTION THAT MAKES IT INTO FORECAST AREA WILL EITHER DEVELOP LATE IN THE AFTN ON FRONT OVER SWRN ZONES OR SW OF NEBRASKA AND THEN ATTEMPT TO BUILD INTO SERN ZONES THIS EVENING. THUS POPS WERE DROPPED MUCH OF THE AREA N THROUGH E OF OMA ALONG WITH FAR SERN NEBRASKA THIS AFTN AND TRIMMED BACK ALL BUT SEVERAL SW COUNTIES FM OMAHA SWWD. ALSO RAISED MAX TEMPS A BIT IN ERN ZONES BASED ON MORNING SOUNDING AND BOOSTED WINDS A LITTLE BOTH AHEAD OF AND BEHIND FRONT. CHERMOK && .PREV DISCUSSION... /ISSUED 631 AM CDT MON APR 2 2012/ DISCUSSION... WV IMAGERY SHOWING FEATURE OF CONCERN...DEEP LONGWAVE TROF...OVER THE ROCKIES SLOWLY MIGRATING TO THE EAST THIS MORNING WHILE SFC LOW PRESSURE WAS CENTERED IN NERN CO. MODELS IN DECENT AGREEMENT THAT THE LONGWAVE TROF WILL FORM INTO A CLOSED LOW OVER THE SRN PLAINS AND BECOME CUT OFF BY EARLY TUESDAY MORNING...THEN EVENTUALLY LIFTING ACROSS THE CENTRAL PLAINS EARLY THURSDAY. FOR TODAY...ANTICIPATED COLD FRONT WILL SWEEP INTO THE CENTRAL PLAINS AS CO SFC LOW TREKS TOWARD THE MID MS VLY. VARIOUS TIME-SERIES PROGS PUT THE FRONT THRU THE METRO-AREA SOMETIME EARLY THIS EVENING. PW VALUES AROUND 1.25" AND KI 35-40 INDICATE ENVIRONMENT WILL BE MOISTURE RICH. THAT...IN COMBINATION WITH FAVORABLE MUCAPE/EFF SRH/EFF BULK WIND DIFFERENCE PARAMETERS SUGGEST LATE AFTN/EARLY EVENING SEVERE STORM DEVELOPMENT A DISTINCT POSSIBILITY...PARTICULARLY AREAS SOUTH OF I-80. FORTUNATELY...APPEARS THAT TOR THREAT WILL BE MINIMAL DUE TO ML LFC PROGGED AOA 2200M. PCPN CHANCES CONTINUE THEN TUESDAY THROUGH THURSDAY MAINLY SOUTH AS AREA FALLS UNDER INFLUENCE OF CLOSED LOW DYNAMICS TREKKING ACROSS KS. OTHERWISE THIS COOLER AIRMASS FILTERING IN THIS WEEK WILL BRING A NOTICEABLE CHANGE. NEVERTHELESS...NEAR NORMAL MAX TEMPS WILL BE QUITE ATTAINABLE. DEE AVIATION... 12Z TAFS FOR KOFK...KLNK AND KOMA. GUSTY SOUTH TO SOUTHWEST WINDS UP TO 25KTS WILL DEVELOP DURING THE MORNING AHEAD OF A COLD FRONT MOVING INTO EASTERN NEBRASKA THIS AFTERNOON. THAT FRONT SHOULD REACH KOFK AROUND 22Z...KLNK NEAR 01Z AND KOMA NEAR 02Z. NORTHWEST WINDS GUSTING OVER 25KTS WILL FOLLOW THE FRONT WITH CIGS DECREASING TO MVFR...WITH A GRADUAL LOWERING TO BELOW FL020 AFTER 06Z. A FEW SHOWERS ARE ALSO POSSIBLE BEHIND THE FRONT OVERNIGHT. THERE IS A SLIGHT CHANCE THUNDERSTORMS COULD DEVELOP NEAR KOMA AND KLNK AFTER 21Z AS THE COLD FRONT APPROACHES. DERGAN && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
709 AM CDT MON APR 2 2012 .AVIATION...12Z KGRI TAF. OVERALL...CONFIDENCE IS A BIT LOWER THAN USUAL WITH REGARD TO WIND AND CEILING TRENDS THROUGH THE PERIOD...AS MODELS CONTINUE TO STRUGGLE WITH THE TIMING OF THE PRIMARY COLD FRONTAL PASSAGE...AND IN GENERAL ARE SLOWING IT DOWN. AS A RESULT...ANTICIPATE FAIRLY LIGHT SOUTH-SOUTHWESTERLY BREEZES THIS MORNING...BEFORE NORTHWEST WINDS FINALLY KICK IN DURING THE EARLY TO MID AFTERNOON HOURS BEHIND THE INITIAL FRONTAL PASSAGE. HOWEVER...IT MAY BE UNTIL LATE AFTERNOON/EARLY EVENING BEFORE POTENTIAL GUSTS TO AROUND 30KT OR HIGHER ARE FINALLY REALIZED. MOVING TO CEILING AND PRECIPITATION TRENDS...KEPT THEME FROM PREVIOUS FORECAST OF A FAIRLY SOLID CEILING IN THE 2000-3000 FT RANGE SETTLING IN DURING THE EVENING AND OVERNIGHT HOURS...BUT TIMING COULD EASILY BE OFF BY A FEW HOURS. FINALLY...REGARDING PRECIPITATION CHANCES...THE EVENING HOURS COULD SEE LEGITIMATE STRONG THUNDERSTORM ACTIVITY WITHIN 50-75 MILES SOUTH-SOUTHEAST OF KGRI...BUT AT THIS TIME EXPECT THIS TO STAY FAR ENOUGH AWAY TO OMIT A MENTION. DID HOWEVER INTRODUCE A VICINITY SHOWER MENTION FOR THE LATE NIGHT HOURS. STAY TUNED FOR PLENTY OF POTENTIAL TWEAKING TO THE TAF OVER THE NEXT 24 HOURS... && .PREV DISCUSSION... /ISSUED 419 AM CDT MON APR 2 2012/ SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. THE PATTERN ALOFT REVEALED AN UPPER TROUGH IN THE ROCKIES WITH THE MID/UPPER CIRCULATION CLOSING OFF NEAR THE FOUR CORNERS REGION. AHEAD OF THIS SYSTEM...SOUTHWEST FLOW WAS IN PLACE ACROSS THE CENTRAL PLAINS WHILE UPPER RIDGE HAD SHIFTED EAST OF THE MISSOURI RIVER. AT THE SURFACE...LOW PRESSURE WAS CENTERED IN FAR NORTHWEST KANSAS...WITH COOL FRONTAL BOUNDARY EXTENDING FROM VTN TO KSNY...AND DRYLINE EXTENDED ACROSS EASTERN CO. PRESSURE RISES BEHIND THE FRONT BEHIND THE FRONT AVERAGED 3-5MB. THERE HAVE BEEN SOME DISTINCT CHANGES IN FRONTAL TIMING...WINDS AND POTENTIAL FOR CONVECTION TODAY. SURFACE FRONT STILL ENTERS OUR WESTERN CWA AROUND 12Z...BUT SLOWS AND STALLS ACROSS OUR SOUTHEAST CWA AROUND MID AFTERNOON. INSTABILITY PROGS INDICATE MUCAPE AROUND 1500 J/KG IN OUR FAR SOUTHEAST CWA FOR A FEW HOURS WITH HIGHER CAPE AXIS FARTHER SOUTHEAST AHEAD OF THE BOUNDARY...AND A BRIEF PERIOD OF EFFECTIVE SHEAR OF 30 TO 40KTS RESIDE ALONG THE BOUNDARY...GENERALLY BETWEEN 21 AND 00Z. AS THE BOUNDARY STALLS IN OUR SOUTHEAST...CAN NO LONGER RULE OUT CONVECTIVE POTENTIAL AND A WINDOW OF OPPORTUNITY FOR SEVERE WEATHER WITH STORMS CAPABLE OF PRODUCING LARGE HAIL/DAMAGING WINDS. 4KM SPC WRF DEVELOPS CONVECTION ACROSS OUR SOUTHERN CWA IN VCNTY OF BOUNDARY AND WITH CONTINUING TRENDS OF FRONT SLOWING DOWN...HAVE RETURNED TSTMS TO FORECAST. ALSO DUE TO SLOWER FRONTAL PROGRESSION TODAY...THIS ALSO HAS AN IMPACT ON STRENGTH OF WINDS ACROSS OUR REGION. THE CORRIDOR OF STRONGEST PRESSURE RISES THIS MORNING SLIDE SOUTH FROM WESTERN NEBRASKA INTO WESTERN KANSAS AND SFC GRADIENT REMAINS TIGHTEST ACROSS THE WESTERN HALF OF NEBRASKA INTO NW KANSAS. FRONT DOES NOT REACH OUR EASTERN AND SOUTHEAST COUNTIES UNTIL THIS AFTERNOON OR EARLY EVENING AND WINDS WILL INITIALLY BE GUSTY OUT OF THE SOUTH BUT NOT AT WIND ADVISORY CRITERIA. AS FRONT PUSHES THRU OUR SOUTHEAST CWA IN THE EVENING...A SECONDARY SURGE OF PRESSURE RISES AND CORRIDOR OF 40KT MID LEVEL WINDS MOVE THRU BEGINNING GENERALLY AROUND 00Z AND LINGERING/SPREADING SOUTHWARD UNTIL AROUND MIDNIGHT. WHAT THIS MEANS IS THAT REACHING WIND ADVISORY CRITERIA ESPECIALLY IN OUR EAST/SOUTHEAST IS LOOKING LESS LIKELY UNTIL POTENTIALLY CLOSER TO 00Z WITH SECONDARY SURGE OF FRONT/PRESSURE RISES. OUR WESTERN COUNTIES WILL STILL STAND A BETTER CHC FOR WIND ADVISORY CRITERIA BUT IN ESSENCE MAY BE MORE OF A BUFFER TO THE EVEN HIGHER WINDS ACROSS WESTERN NEBRASKA AND KANSAS. FOR HEADLINE...OPTIONS ARE TO EITHER CANCEL EASTERN/SOUTHEAST PORTION OR HOLD OFF ON TIMING UNTIL THE EVENING HOURS. HAVE OPTED TO REMOVE WIND ADVISORY IN THE EAST AND MAINTAIN A BUFFER IN THE WEST. LATEST HRRR SUGGESTS STRONGER WINDS COULD HOLD OFF EVEN IN OUR WEST UNTIL AFTN WHILE THE INITIALLY STRONGER WINDS WILL BE FM THE SOUTH IN OUR EASTERN COUNTIES. OTHER CHANGE IN MODELS...WHICH HAS BEEN A GENERAL TREND AS WELL...IS THE FARTHER NORTH TRACK OF THE UPPER LOW AS IT LIFTS FM THE TX/OK PANHANDLES TUESDAY. GENERAL CONSENSUS IS THAT LOW WILL LIFT AND TRACK ACROSS KANSAS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...AND THE ECMWF REMAINS SLOWER WITH PROGRESSION WHICH COULD POTENTIALLY LINGER PCPN CHCS BEYOND WEDNESDAY NIGHT. LATEST TRACK PROMISES TO PROVIDE A DECENT RAIN EVENT ACROSS THE CENTRAL PLAINS MAINLY FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. POPS HAVE BEEN TRENDED UPWARD INTO LIKELY CATEGORY...AND SOME DECENT SPRING RAINFALL TOTALS ARE POSSIBLE WITH PRECIPITABLE WATER VALUES AVERAGING 0.75 TO JUST OVER AN INCH. HAVE KEPT THUNDER WORDING OUT AS INSTABILITY PARAMETERS ARE RATHER MEAGER BUT WOULD NOT BE SURPRISED TO SEE AN OUTSIDE LIGHTNING STRIKE HERE OR THERE...ESPECIALLY IN OUR SOUTHEAST WHERE MUCAPES ARE NOT ZERO...JUST RATHER LOW. LONG TERM...THURSDAY THROUGH SUNDAY. PRIMARY FOCUS THROUGH THIS 4-DAY PERIOD IS THE RISK FOR THUNDERSTORMS IN THE FRI-SAT TIME FRAME...BUT MAINLY CENTERED FRIDAY NIGHT AND NOT EVEN IN LIKELY POP TERRITORY YET. ALTHOUGH NOT NEARLY AS WARM AS LATELY...HIGH TEMPS THROUGH THIS PERIOD SHOULD NONETHELESS AVERAGE SOLIDLY IN THE 60S MOST AREAS...OR STILL SLIGHTLY ABOVE NORMAL FOR EARLY APRIL. AS FOR OVERNIGHT LOWS...WILL HAVE TO KEEP AN EYE OUT AS EARLY AS SAT NIGHT FOR POSSIBLE FROST POTENTIAL. STARTING OFF THURSDAY...00Z ECMWF/GFS RUNS ARE IN DECENT AGREEMENT DEPICTING A DEPARTING MID LEVEL CLOSED LOW GENERALLY WANDERING SOMEWHERE OVER MO. AT THE SAME TIME...A FAIRLY EXPANSIVE UPSTREAM TROUGH WILL BE CENTERED OVER THE WESTERN 1/3 OF THE CONUS. AT LEAST FOR NOW...LEFT THURSDAY DAYTIME DRY...ALTHOUGH THERE ARE SOME HINTS THAT AT LEAST SOME EASTERN AREAS COULD STILL BE PRONE TO SOME LINGERING LIGHT RAIN SHOWERS. FOR NOW THOUGH WILL STAY THE COURSE AND REMAIN TRUE TO THE DRY FCST INITIALIZED BY THE ALLBLEND MODEL PROCEDURE. FOR HIGH TEMPS...NUDGED DOWN A FEW DEGREES MOST AREAS GIVEN PREDOMINANT EASTERLY LOW LEVEL FLOW...WITH THE MAJORITY OF THE CWA IN THE 62-65 RANGE. KEPT THURS NIGHT DRY AS PRIMARY LOW LEVEL JET AXIS AND RESULTANT FOCUS FOR POSSIBLE CONVECTION APPEARS TO REMAIN AT LEAST SLIGHTLY WEST OF THE CWA. FRIDAY/FRIDAY NIGHT...THIS 24 HOUR PERIOD APPEARS TO FEATURE THE PRIMARY RISK FOR THUNDERSTORMS IN THE LONG TERM...ESPECIALLY ON FRIDAY NIGHT. DURING THE DAY...SOUTHEAST WINDS WILL PICK UP INTO BREEZY TERRITORY AS PRESSURES FALL OVER THE HIGH PLAINS...BUT AT THIS TIME SPEEDS LOOK TO REMAIN BELOW ADVISORY CRITERIA. ALLBLEND PROCEDURE INTRODUCED A SLIGHT CHANCE OF STORMS DURING THE DAY ACROSS WESTERN COUNTIES...AND OPTED TO RUN WITH IT...ALTHOUGH CONFIDENCE IS RATHER LOW GIVEN EXPECTATION OF WEAK FORCING AND SOME CAPPING...DESPITE THE ECMWF AND GFS BOTH ADVERTISING A NARROW...FAIRLY WEAK INSTABILITY AXIS SETTING UP NEAR THE SOUTHERN/WESTERN EDGES OF THE CWA THROUGH THE DAY. IN ALL HONESTY THOUGH...THESE SLIGHT CHANCES DURING THE DAY ARE ALREADY ON SOMEWHAT SHAKY GROUND RIGHT OUT OF THE GATE. BETTER CHANCES...ALTHOUGH STILL ONLY IN THE 30-40 PERCENT RANGE AT THIS TIME...ARRIVE FRIDAY NIGHT AS FORCING FROM THE LEADING SHORTWAVE EMANATING FROM THE WESTERN CONUS TROUGH SWINGS ALONG A TRACK FROM WY/NORTHERN CO ACROSS WESTERN NE INTO SD. ALTHOUGH THIS TAKES THE BULK OF THE LARGE SCALE FORCING NORTH OF THE CWA...BOTH MODELS GENERATE QPF...WITH THE GFS ADVERTISING A SURGE OF INSTABILITY DURING THE NIGHT...WITH MUCAPE VALUES CLIMBING TO AROUND 1500 J/KG IN THE PRESENCE OF AT LEAST 40KT OF DEEP LAYER SHEAR. FOR NOW WILL INTRODUCE A STRONG STORM MENTION IN THE HWO...BUT WILL NEED TO KEEP A CLOSE EYE ON SEVERE POTENTIAL OVER NEXT FEW DAYS. SATURDAY...MID RANGE MODELS CONTINUE TO AGREE ON THE LARGER SCALE PATTERN...WITH THE MAIN MID LEVEL WAVE CROSSING THE DAKOTAS TOWARD MN...WHILE A SURFACE COLD FRONT TRACKS ACROSS THE CWA AND USHERS IN DRIER/MORE STABLE AIR. ALLBLEND MODEL KEPT SOME TOKEN SLIGHT POPS ACROSS FAR NORTHEAST AND SOUTHEAST PORTIONS OF THE CWA DURING THE DAY...AND WILL LET IT RIDE FOR NOW. SAT NIGHT/SUNDAY...CONFIDENCE IS RATHER HIGH AT THIS TIME RANGE THAT DRY CONDITIONS WILL PREVAIL IN THE WAKE OF THE DEPARTING WAVE...ALTHOUGH MODELS START TO DIVERGE ALOFT WITH THE ECMWF ADVERTISING BROAD WEST-NORTHWEST FLOW WHILE THE GFS IS MORE WEST- SOUTHWEST. DOWN LOW HOWEVER...THERE IS A DECENT SIGNAL FOR HIGH PRESSURE TO RULE THE SCENE ON SATURDAY NIGHT WITH FAIRLY LIGHT WINDS. ALTHOUGH CURRENT FORECAST KEEPS LOWS UP IN THE UPPER 30S- LOW 40S FOR MOST OF THE CWA...WILL HAVE TO MONITOR FOR THE POTENTIAL FOR A MORE WIDESPREAD LOW-MID 30S...WHICH COULD AT LEAST BRING SOME FROST POTENTIAL INTO PLAY. CERTAINLY TOO EARLY AT THIS TIME TO FORMALLY PUT IT IN THE FORECAST. PEEKING AHEAD A BIT INTO THE WEEK OF APRIL 9TH...COULD BE A FEW MORE RISKS FOR OVERNIGHT TEMPS DROPPING DOWN INTO AT LEAST THE FROST POSSIBILITY RANGE...WHICH IS RIGHT IN LINE WITH CLIMATOLOGY FOR MID APRIL. AVIATION...06Z KGRI TAF. WIND WILL BE THE BIGGEST FACTOR FOR THIS FORECAST. EAST TO SOUTHEAST WIND WILL PREVAIL OVERNIGHT AND WILL CONTINUE TO BE A BIT ON THE BREEZY SIDE. A COLD FRONT WILL MOVE IN TOWARD MID-MORNING AND WILL SWITCH WIND DIRECTION TO THE NORTH NORTHWEST AND WILL BECOME VERY GUSTY FROM STRONG HEIGHT RISES...ESPECIALLY TOWARD EVENING. ANY PRECIPITATION SHOULD HOLD OFF TO THE SOUTH AND WELL AFTER THE FRONT PASSES THROUGH. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 11 PM CDT THIS EVENING FOR NEZ061-073-083. WIND ADVISORY FROM 11 AM THIS MORNING TO 11 PM CDT THIS EVENING FOR NEZ039-046-060-072-082. KS...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 11 PM CDT THIS EVENING FOR KSZ005-017. && $$ SHORT TERM...FAY LONG TERM/AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
419 AM CDT MON APR 2 2012 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT. THE PATTERN ALOFT REVEALED AN UPPER TROUGH IN THE ROCKIES WITH THE MID/UPPER CIRCULATION CLOSING OFF NEAR THE FOUR CORNERS REGION. AHEAD OF THIS SYSTEM...SOUTHWEST FLOW WAS IN PLACE ACROSS THE CENTRAL PLAINS WHILE UPPER RIDGE HAD SHIFTED EAST OF THE MISSOURI RIVER. AT THE SURFACE...LOW PRESSURE WAS CENTERED IN FAR NORTHWEST KANSAS...WITH COOL FRONTAL BOUNDARY EXTENDING FROM VTN TO KSNY...AND DRYLINE EXTENDED ACROSS EASTERN CO. PRESSURE RISES BEHIND THE FRONT BEHIND THE FRONT AVERAGED 3-5MB. THERE HAVE BEEN SOME DISTINCT CHANGES IN FRONTAL TIMING...WINDS AND POTENTIAL FOR CONVECTION TODAY. SURFACE FRONT STILL ENTERS OUR WESTERN CWA AROUND 12Z...BUT SLOWS AND STALLS ACROSS OUR SOUTHEAST CWA AROUND MID AFTERNOON. INSTABILITY PROGS INDICATE MUCAPE AROUND 1500 J/KG IN OUR FAR SOUTHEAST CWA FOR A FEW HOURS WITH HIGHER CAPE AXIS FARTHER SOUTHEAST AHEAD OF THE BOUNDARY...AND A BRIEF PERIOD OF EFFECTIVE SHEAR OF 30 TO 40KTS RESIDE ALONG THE BOUNDARY...GENERALLY BETWEEN 21 AND 00Z. AS THE BOUNDARY STALLS IN OUR SOUTHEAST...CAN NO LONGER RULE OUT CONVECTIVE POTENTIAL AND A WINDOW OF OPPORTUNITY FOR SEVERE WEATHER WITH STORMS CAPABLE OF PRODUCING LARGE HAIL/DAMAGING WINDS. 4KM SPC WRF DEVELOPS CONVECTION ACROSS OUR SOUTHERN CWA IN VCNTY OF BOUNDARY AND WITH CONTINUING TRENDS OF FRONT SLOWING DOWN...HAVE RETURNED TSTMS TO FORECAST. ALSO DUE TO SLOWER FRONTAL PROGRESSION TODAY...THIS ALSO HAS AN IMPACT ON STRENGTH OF WINDS ACROSS OUR REGION. THE CORRIDOR OF STRONGEST PRESSURE RISES THIS MORNING SLIDE SOUTH FROM WESTERN NEBRASKA INTO WESTERN KANSAS AND SFC GRADIENT REMAINS TIGHTEST ACROSS THE WESTERN HALF OF NEBRASKA INTO NW KANSAS. FRONT DOES NOT REACH OUR EASTERN AND SOUTHEAST COUNTIES UNTIL THIS AFTERNOON OR EARLY EVENING AND WINDS WILL INITIALLY BE GUSTY OUT OF THE SOUTH BUT NOT AT WIND ADVISORY CRITERIA. AS FRONT PUSHES THRU OUR SOUTHEAST CWA IN THE EVENING...A SECONDARY SURGE OF PRESSURE RISES AND CORRIDOR OF 40KT MID LEVEL WINDS MOVE THRU BEGINNING GENERALLY AROUND 00Z AND LINGERING/SPREADING SOUTHWARD UNTIL AROUND MIDNIGHT. WHAT THIS MEANS IS THAT REACHING WIND ADVISORY CRITERIA ESPECIALLY IN OUR EAST/SOUTHEAST IS LOOKING LESS LIKELY UNTIL POTENTIALLY CLOSER TO 00Z WITH SECONDARY SURGE OF FRONT/PRESSURE RISES. OUR WESTERN COUNTIES WILL STILL STAND A BETTER CHC FOR WIND ADVISORY CRITERIA BUT IN ESSENCE MAY BE MORE OF A BUFFER TO THE EVEN HIGHER WINDS ACROSS WESTERN NEBRASKA AND KANSAS. FOR HEADLINE...OPTIONS ARE TO EITHER CANCEL EASTERN/SOUTHEAST PORTION OR HOLD OFF ON TIMING UNTIL THE EVENING HOURS. HAVE OPTED TO REMOVE WIND ADVISORY IN THE EAST AND MAINTAIN A BUFFER IN THE WEST. LATEST HRRR SUGGESTS STRONGER WINDS COULD HOLD OFF EVEN IN OUR WEST UNTIL AFTN WHILE THE INITIALLY STRONGER WINDS WILL BE FM THE SOUTH IN OUR EASTERN COUNTIES. OTHER CHANGE IN MODELS...WHICH HAS BEEN A GENERAL TREND AS WELL...IS THE FARTHER NORTH TRACK OF THE UPPER LOW AS IT LIFTS FM THE TX/OK PANHANDLES TUESDAY. GENERAL CONSENSUS IS THAT LOW WILL LIFT AND TRACK ACROSS KANSAS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...AND THE ECMWF REMAINS SLOWER WITH PROGRESSION WHICH COULD POTENTIALLY LINGER PCPN CHCS BEYOND WEDNESDAY NIGHT. LATEST TRACK PROMISES TO PROVIDE A DECENT RAIN EVENT ACROSS THE CENTRAL PLAINS MAINLY FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. POPS HAVE BEEN TRENDED UPWARD INTO LIKELY CATEGORY...AND SOME DECENT SPRING RAINFALL TOTALS ARE POSSIBLE WITH PRECIPITABLE WATER VALUES AVERAGING 0.75 TO JUST OVER AN INCH. HAVE KEPT THUNDER WORDING OUT AS INSTABILITY PARAMETERS ARE RATHER MEAGER BUT WOULD NOT BE SURPRISED TO SEE AN OUTSIDE LIGHTNING STRIKE HERE OR THERE...ESPECIALLY IN OUR SOUTHEAST WHERE MUCAPES ARE NOT ZERO...JUST RATHER LOW. .LONG TERM...THURSDAY THROUGH SUNDAY. PRIMARY FOCUS THROUGH THIS 4-DAY PERIOD IS THE RISK FOR THUNDERSTORMS IN THE FRI-SAT TIME FRAME...BUT MAINLY CENTERED FRIDAY NIGHT AND NOT EVEN IN LIKELY POP TERRITORY YET. ALTHOUGH NOT NEARLY AS WARM AS LATELY...HIGH TEMPS THROUGH THIS PERIOD SHOULD NONETHELESS AVERAGE SOLIDLY IN THE 60S MOST AREAS...OR STILL SLIGHTLY ABOVE NORMAL FOR EARLY APRIL. AS FOR OVERNIGHT LOWS...WILL HAVE TO KEEP AN EYE OUT AS EARLY AS SAT NIGHT FOR POSSIBLE FROST POTENTIAL. STARTING OFF THURSDAY...00Z ECMWF/GFS RUNS ARE IN DECENT AGREEMENT DEPICTING A DEPARTING MID LEVEL CLOSED LOW GENERALLY WANDERING SOMEWHERE OVER MO. AT THE SAME TIME...A FAIRLY EXPANSIVE UPSTREAM TROUGH WILL BE CENTERED OVER THE WESTERN 1/3 OF THE CONUS. AT LEAST FOR NOW...LEFT THURSDAY DAYTIME DRY...ALTHOUGH THERE ARE SOME HINTS THAT AT LEAST SOME EASTERN AREAS COULD STILL BE PRONE TO SOME LINGERING LIGHT RAIN SHOWERS. FOR NOW THOUGH WILL STAY THE COURSE AND REMAIN TRUE TO THE DRY FCST INITIALIZED BY THE ALLBLEND MODEL PROCEDURE. FOR HIGH TEMPS...NUDGED DOWN A FEW DEGREES MOST AREAS GIVEN PREDOMINANT EASTERLY LOW LEVEL FLOW...WITH THE MAJORITY OF THE CWA IN THE 62-65 RANGE. KEPT THURS NIGHT DRY AS PRIMARY LOW LEVEL JET AXIS AND RESULTANT FOCUS FOR POSSIBLE CONVECTION APPEARS TO REMAIN AT LEAST SLIGHTLY WEST OF THE CWA. FRIDAY/FRIDAY NIGHT...THIS 24 HOUR PERIOD APPEARS TO FEATURE THE PRIMARY RISK FOR THUNDERSTORMS IN THE LONG TERM...ESPECIALLY ON FRIDAY NIGHT. DURING THE DAY...SOUTHEAST WINDS WILL PICK UP INTO BREEZY TERRITORY AS PRESSURES FALL OVER THE HIGH PLAINS...BUT AT THIS TIME SPEEDS LOOK TO REMAIN BELOW ADVISORY CRITERIA. ALLBLEND PROCEDURE INTRODUCED A SLIGHT CHANCE OF STORMS DURING THE DAY ACROSS WESTERN COUNTIES...AND OPTED TO RUN WITH IT...ALTHOUGH CONFIDENCE IS RATHER LOW GIVEN EXPECTATION OF WEAK FORCING AND SOME CAPPING...DESPITE THE ECMWF AND GFS BOTH ADVERTISING A NARROW...FAIRLY WEAK INSTABILITY AXIS SETTING UP NEAR THE SOUTHERN/WESTERN EDGES OF THE CWA THROUGH THE DAY. IN ALL HONESTY THOUGH...THESE SLIGHT CHANCES DURING THE DAY ARE ALREADY ON SOMEWHAT SHAKY GROUND RIGHT OUT OF THE GATE. BETTER CHANCES...ALTHOUGH STILL ONLY IN THE 30-40 PERCENT RANGE AT THIS TIME...ARRIVE FRIDAY NIGHT AS FORCING FROM THE LEADING SHORTWAVE EMANATING FROM THE WESTERN CONUS TROUGH SWINGS ALONG A TRACK FROM WY/NORTHERN CO ACROSS WESTERN NE INTO SD. ALTHOUGH THIS TAKES THE BULK OF THE LARGE SCALE FORCING NORTH OF THE CWA...BOTH MODELS GENERATE QPF...WITH THE GFS ADVERTISING A SURGE OF INSTABILITY DURING THE NIGHT...WITH MUCAPE VALUES CLIMBING TO AROUND 1500 J/KG IN THE PRESENCE OF AT LEAST 40KT OF DEEP LAYER SHEAR. FOR NOW WILL INTRODUCE A STRONG STORM MENTION IN THE HWO...BUT WILL NEED TO KEEP A CLOSE EYE ON SEVERE POTENTIAL OVER NEXT FEW DAYS. SATURDAY...MID RANGE MODELS CONTINUE TO AGREE ON THE LARGER SCALE PATTERN...WITH THE MAIN MID LEVEL WAVE CROSSING THE DAKOTAS TOWARD MN...WHILE A SURFACE COLD FRONT TRACKS ACROSS THE CWA AND USHERS IN DRIER/MORE STABLE AIR. ALLBLEND MODEL KEPT SOME TOKEN SLIGHT POPS ACROSS FAR NORTHEAST AND SOUTHEAST PORTIONS OF THE CWA DURING THE DAY...AND WILL LET IT RIDE FOR NOW. SAT NIGHT/SUNDAY...CONFIDENCE IS RATHER HIGH AT THIS TIME RANGE THAT DRY CONDITIONS WILL PREVAIL IN THE WAKE OF THE DEPARTING WAVE...ALTHOUGH MODELS START TO DIVERGE ALOFT WITH THE ECMWF ADVERTISING BROAD WEST-NORTHWEST FLOW WHILE THE GFS IS MORE WEST- SOUTHWEST. DOWN LOW HOWEVER...THERE IS A DECENT SIGNAL FOR HIGH PRESSURE TO RULE THE SCENE ON SATURDAY NIGHT WITH FAIRLY LIGHT WINDS. ALTHOUGH CURRENT FORECAST KEEPS LOWS UP IN THE UPPER 30S- LOW 40S FOR MOST OF THE CWA...WILL HAVE TO MONITOR FOR THE POTENTIAL FOR A MORE WIDESPREAD LOW-MID 30S...WHICH COULD AT LEAST BRING SOME FROST POTENTIAL INTO PLAY. CERTAINLY TOO EARLY AT THIS TIME TO FORMALLY PUT IT IN THE FORECAST. PEEKING AHEAD A BIT INTO THE WEEK OF APRIL 9TH...COULD BE A FEW MORE RISKS FOR OVERNIGHT TEMPS DROPPING DOWN INTO AT LEAST THE FROST POSSIBILITY RANGE...WHICH IS RIGHT IN LINE WITH CLIMATOLOGY FOR MID APRIL. && .AVIATION...06Z KGRI TAF. WIND WILL BE THE BIGGEST FACTOR FOR THIS FORECAST. EAST TO SOUTHEAST WIND WILL PREVAIL OVERNIGHT AND WILL CONTINUE TO BE A BIT ON THE BREEZY SIDE. A COLD FRONT WILL MOVE IN TOWARD MID-MORNING AND WILL SWITCH WIND DIRECTION TO THE NORTH NORTHWEST AND WILL BECOME VERY GUSTY FROM STRONG HEIGHT RISES...ESPECIALLY TOWARD EVENING. ANY PRECIPITATION SHOULD HOLD OFF TO THE SOUTH AND WELL AFTER THE FRONT PASSES THROUGH. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 11 PM CDT THIS EVENING FOR NEZ061-073-083. WIND ADVISORY FROM 11 AM THIS MORNING TO 11 PM CDT THIS EVENING FOR NEZ039-046-060-072-082. KS...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 11 PM CDT THIS EVENING FOR KSZ005-017. && $$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
902 PM EDT TUE APR 3 2012 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL PASS SOUTH OF NEW YORK STATE TONIGHT AND MAY BRING A FEW ISOLATED SHOWERS TO PARTS OF WESTERN NEW YORK. ARCTIC HIGH PRESSURE WILL BUILD SOUTH ACROSS THE REGION WEDNESDAY WITH COOLER TEMPERATURES AND FAIR WEATHER RETURNING FOR THE REST OF THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... A WEAK SURFACE LOW NEAR ACROSS ILLINOIS AND INDIANA WILL TRACK WELL TO THE SOUTH OF THE REGION OVERNIGHT. AN ASSOCIATED WARM FRONT EXTENDS TO THE ENE OF THE LOW...TOWARD WESTERN NEW YORK. THE 00Z BUFFALO SOUNDING SHOWS VERY DRY AIR IN PLACE BENEATH 800 MB...WITH THIS DRY LAYER LIKELY TO KEEP MOST OF WESTERN NEW YORK DRY. HOWEVER...900 PM RADAR DOES SHOW SOME SHOWERS ACROSS LAKE ERIE WHICH MAY CLIP WESTERN PORTIONS OF THE SOUTHERN TIER THIS EVENING. THE 18Z NAM AND HRRR DO CAPTURE THIS FEATURE TO SOME DEGREE...BRINGING IT ACROSS THE SOUTHERN TIER DURING THE EVENING HOURS. IF ANYTHING...THESE MODELS MAY BE A BIT FAR NORTH GIVEN RADAR TRENDS. FORECAST MAINTAINS CHANCE POPS IN SOUTHERNMOST PORTIONS OF THE CWA. RADAR SHOWS SOME WEAK RETURNS ACROSS THE NIAGARA FRONTIER...WHICH APPEAR TO BE SPRINKLES AT BEST. MOSTLY CLOUDY SKIES THE FIRST HALF OF THE NIGHT WILL KEEP AREA TEMPERATURES QUITE A BIT WARMER TONIGHT THAN TUESDAY MORNINGS SUB- FREEZING READINGS. UPPER 30S FOR WESTERN NY AND THE FINGER LAKES AND LOW TO MID 30S FOR THE NORTH COUNTRY. SKIES SHOULD CLEAR FROM NW-SE LATE TONIGHT. ARCTIC HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY BEHIND THE DEPARTING LOW. 850MB TEMPS WEDNESDAY WILL DROP TO AROUND -3C WHICH WILL SUPPORT HIGH TEMPS ONLY REACHING INTO THE LOW 50S ACROSS WESTERN NY DESPITE MAINLY CLEAR SKIES. MORE CLOUDS OVER THE NORTH COUNTRY AND 850MB TEMPS CLOSER TO -4C/-5C WILL KEEP HIGH TEMPS LIMITED TO THE UPPER 40S/LOW 50S. WINDS WEDNESDAY WILL BECOME BREEZY IN THE AFTERNOON AS THE PRESSURE GRADIENT TIGHTENS WITH THE APPROACHING ARCTIC HIGH AND THE SURFACE LOW OVER THE MID-ATLANTIC COAST. NORTHWEST GUSTS MAY APPROACH 20 TO 25 MPH ACROSS THE NORTH COUNTRY AND SOUTHEAST OF THE LAKE. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... IT WILL BE SEASONABLY CHILLY DURING THIS PERIOD AS OUR REGION WILL REMAIN IN THE COLD SIDE OF A WEAKLY ESTABLISHED REX BLOCK. THIS LONGWAVE PATTERN WILL FEATURE A CUT OFF LOW OVER THE PLAINS THAT WILL BE TOPPED BY A HIGH AMPLITUDE RIDGE THAT WILL EXTEND NORTHWARDS PAST HUDSON BAY. WHILE THE UNDERLYING CUT OFF IS FORECAST TO PROGRESS EASTWARD ACROSS THE SOUTHERN STATES DURING THIS TIME FRAME...THE RIDGE WILL BE MUCH SLOWER IN ITS PROGRESSION ACROSS THE GREAT LAKES REGION. DOWNSTREAM FROM THE AFOREMENTIONED RIDGE WILL BE A FAIRLY SHARP TROUGH THAT WILL BE CENTERED OVER QUEBEC AND NEW ENGLAND. THIS WILL HOLD OUR TEMPERATURES AT OR SLIGHTLY BELOW NORMAL FOR THIS PERIOD... WHILE AN EXPANSIVE SFC HIGH WILL KEEP THE VAST MAJORITY OF THE REGION PRECIPITATION FREE. ALL IN ALL...A PRETTY `VANILLA` PERIOD. A ROBUST SHORTWAVE WILL DROP INTO THE BASE OF THE EASTERN CANADIAN TROUGH WEDNESDAY NIGHT...AND AS THIS BUNDLE OF ENERGY CROSSES THE NORTH COUNTRY...THERE MAY BE ENOUGH LOW LEVEL MOISTURE AND LIFT PRESENT TO POSSIBLY GENERATE A COUPLE WIDELY SEPARATED RAIN OR WET SNOW SHOWERS. WILL USE LOW CHC POPS TO COVER THIS MINIMAL POSSIBILITY. THE REMAINDER OF THE FORECAST AREA WILL BE PCPN FREE...BUT WITH ANOTHER FROST OR FREEZE. H85 TEMPS OF -8C WILL HELP TO PUSH OVERNIGHT LOWS BACK DOWN INTO THE 20S AND LOWER 30S. A MASSIVE AREA OF HIGH PRESSURE WILL EASE SOUTHWARDS ACROSS THE UPPER GREAT LAKES ON THURSDAY. THIS WILL PROVIDE OUR FORECAST AREA WITH PARTLY/MSTLY SUNNY SKIES...ALTHOUGH WITH H85 TEMPS STILL COLDER THAN -4C AND SOME RESIDUAL LOW LEVEL MOISTURE IN PLACE...SITES AWAY FROM THE LAKES MAY EXPERIENCE A FEW HOURS OF BROKEN STRATO-CU CLOUD COVER. IT WILL BE A COOL DAY AS WELL WITH MAX TEMPS STRUGGLING TO REACH NORMAL EARLY APRIL VALUES. AS THE LARGE SFC HIGH SETTLES OVER THE ENTIRE GREAT LAKES REGION THURSDAY NIGHT...THE PRESSURE GRADIENT WILL WEAKEN SO THAT VERY GOOD RADIATIONAL COOLING WILL BECOME ESTABLISHED UNDER CLEAR SKIES. THIS WILL SET THE STAGE FOR YET ANOTHER WIDESPREAD FREEZE AWAY FROM THE LAKES. OVERNIGHT LOWS WILL RANGE FROM THE FREEZING MARK NEAR THE LAKE SHORES TO 20 TO 25 IN THE SRN TIER VALLEYS AND EAST OF LAKE ONTARIO. FOR FRIDAY AND FRIDAY NIGHT...A H5 RIDGE WILL SLOWLY PUSH ACROSS THE UPPER GREAT LAKES WHILE THE CORE OF THE SFC HIGH WILL DRIFT TO BE ABOUT LAKE ERIE. THIS WILL PROVIDE OUR FORECAST AREA WITH NEARLY CLOUD FREE SKIES AND SEASONABLE TEMPERATURES. THAT WILL INCLUDE ANOTHER FROSTY NIGHT FRIDAY NIGHT...ESPECIALLY FOR THE SITES WELL AWAY FROM THE LAKES. && .LONG TERM /SATURDAY THROUGH TUESDAY/... FAIR...SEASONABLY MILD WEATHER AT THE START OF THIS PERIOD WILL GIVE WAY TO CHILLY UNSETTLED CONDITIONS AS TROUGHINESS OVER THE HIGH PLAINS OF SASKATCHEWAN WILL DIG SOUTHEAST ACROSS THE GREAT LAKES REGION. THIS FEATURE WILL EVENTUALLY CARVE ITS WAY INTO A LONGWAVE TROUGH OVER THE EASTERN HALF OF NORTH AMERICA. AS A RESULT... TEMPERATURES WILL DEFINITELY TREND DOWNWARDS DURING THIS PERIOD WITH BELOW NORMAL MERCURY READINGS BECOMING ESTABLISHED BY TUESDAY. THESE VALUES WILL LIKELY PERSIST THROUGH AT LEAST MID WEEK. SATURDAY WILL BE THE NICEST DAY OF THIS PERIOD...BY FAR...AS STRONG HIGH PRESSURE WILL DRIFT ACROSS OUR FORECAST AREA. SUN FILLED SKIES WILL BOOST SFC TEMPS INTO THE UPPER 50S TO LOWER 60S FOR MOST AREAS WITH EVEN WARMER CONDITIONS EXPECTED IN THE GENESEE VALLEY. AS THE HIGH MOVES OFF THE EAST COAST SUNDAY NIGHT...A PACIFIC BASED COLD FRONT WILL PUSH ACROSS THE UPPER GREAT LAKES AND MID WEST. THIS FRONT WILL MOVE ACROSS OUR AREA ON SUNDAY...AND WHILE THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE...THERE WILL PROBABLY BE A 3 HOUR WINDOW OF SCT SHOWER ACTIVITY. SHORTWAVE RIDGING IN THE WAKE OF THE FRONT SHOULD PROVIDE US WITH DRY WEATHER SUNDAY NIGHT...BUT ADDITIONAL ENERGY FEEDING INTO THE TROUGH WILL ENCOURAGE THE SYSTEM TO DIG ITS WAY ACROSS LOWER ONTARIO. FALLING HGTS AND COLD ADVECTION FROM THIS PROCESS COULD SUPPORT SOME MORE SHOWERS...MAINLY IN THE AFTERNOON AND MONDAY NIGHT. ON TUESDAY...A DEEP LONGWAVE TROUGH WILL BE ANCHORED IN THE VCNTY OF NEW YORK STATE. THIS WILL KEEP COOL UNSETTLED WEATHER OVER OUR REGION WITH HIGH TEMPERATURES NOT MAKING IT OUT OF THE 40S. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... A FRONTAL BOUNDARY EXTENDING NORTHEAST OF LOW PRESSURE PASSING TO THE SOUTH WILL GET PUSHED TO THE SOUTH...ALLOWING FOR SKIES TO CLEAR LATER TONIGHT. UNTIL THEN...EXPECT MAINLY BKN CLOUDS WITH CIGS WELL ABOVE 3000 FT. THERE WILL BE SCATTERED SHOWERS IN THE VICINITY OF JHW DURING THE EVENING HOURS...OTHERWISE EXPECT TAF LOCATIONS TO REMAIN DRY. SKIES SHOULD SCATTER OUT LATE TONIGHT AND INTO WEDNESDAY MORNING...WITH CONTINUED VFR CONDITIONS. WINDS WILL PICK UP WITH DAYTIME MIXING...WITH GUSTS IN THE 20 TO 25 KT RANGE LIKELY. CLOUDS ALSO MAY INCREASE TO SCT-BKN...BUT WILL LIKELY REMAIN IN THE VFR FLIGHT CATEGORY. AN UPPER LEVEL IMPULSE WILL DROP ACROSS EASTERN NEW YORK WEDNESDAY AFTERNOON...WHICH MAY SPARK A STRAY SHOWER AT ART. OUTLOOK... WEDNESDAY NIGHT...MAINLY VFR. THURSDAY AND FRIDAY...VFR. SATURDAY...VFR. && .MARINE... A WEAK LOW WILL PASS JUST SOUTH OF NEW YORK STATE TONIGHT THEN SETTLE OFF THE EAST COAST BY WEDNESDAY MORNING WITH NO IMPACT TO WIND AND WAVE CONDITIONS ACROSS THE LAKES. A MODEST NORTH TO NORTHWEST FLOW OF COLDER AIR WILL SET UP ACROSS THE LAKES WEDNESDAY AND THURSDAY AS ARCTIC HIGH PRESSURE BUILDS SOUTH ACROSS NY. THE RESULTING WINDS AND WAVES MAY APPROACH SMALL CRAFT ADVISORY LEVELS ALONG THE EAST AND SOUTH SHORES OF LAKE ONTARIO IN THE AFTERNOON. && .CLIMATE... THE MONTHLY CLM CLIMATE SUMMARIES HAVE BEEN UPDATED TO INCLUDE THE NARRATIVE SECTION AT THE BOTTOM. THEY ARE AVAILABLE ON OUR WEBSITE UNDER THE CLIMATE SECTION. HERE ARE SOME TIDBITS BELOW... MARCH 2012 IS A MONTH FOR THE RECORD BOOKS AS AN UNSEASONABLE AND PERSISTENT WARM PATTERN REMAINED ACROSS THE EASTERN US. FOR BUFFALO MARCH FINISHED WITH AN AVERAGE TEMPERATURE OF 47.4 DEGREES WHICH IS +13.4 DEGREES ABOVE NORMAL...AND 2.9 DEGREES WARMER THAN THE PREVIOUS WARMEST MARCH. THIS 2.9 DEGREES IS THE LARGEST SEPARATION BETWEEN WARMEST...AND 2ND WARMEST FOR ANY MONTH IN BUFFALO...WITH THE NOW SECOND LARGEST SEPARATION 2.6 DEGREES FOR THE TWO WARMEST MONTHS OF SEPTEMBER. FOR ROCHESTER MARCH FINISHED WITH AN AVERAGE TEMPERATURE OF 47.3 DEGREES WHICH IS +13.0 DEGREES ABOVE NORMAL...AND 3.5 DEGREES WARMER THAN THE PREVIOUS WARMEST MARCH. THIS 3.5 DEGREES IS THE LARGEST SEPARATION BETWEEN WARMEST...AND 2ND WARMEST FOR ANY MONTH IN ROCHESTER WITH THE NOW SECOND LARGEST SEPARATION 3.1 DEGREES FOR THE TWO WARMEST MONTHS OF SEPTEMBER. FOR BOTH CITIES MARCH FINISHED WARMER THAN THE NORMAL APRIL. THE 47.4 DEGREES AVERAGE MARCH 2012 TEMPERATURE IN BUFFALO WAS 1.5 DEGREES WARMER THAN THE NORMAL APRIL VALUE. FOR ROCHESTER THE 47.3 DEGREES AVERAGE MARCH 2012 TEMPERATURE WAS 1.0 DEGREES WARMER THAN THE NORMAL APRIL VALUE. BUFFALO ESTABLISHED SEVEN NEW RECORD HIGH TEMPERATURES IN MARCH 2012...WHILE ROCHESTER ESTABLISHED THREE NEW RECORD HIGH TEMPERATURES. BOTH CITIES SET 5 NEW RECORD WARM MINIMUM TEMPERATURES. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...SMITH NEAR TERM...APFFEL/SMITH SHORT TERM...RSH LONG TERM...RSH AVIATION...APFFEL MARINE...SMITH CLIMATE...THOMAS/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
721 PM EDT TUE APR 3 2012 .SYNOPSIS... AN AREA OF LOW PRESSURE WILL PASS SOUTH OF NEW YORK STATE TONIGHT AND MAY BRING A FEW ISOLATED SHOWERS TO PARTS OF WESTERN NEW YORK. ARCTIC HIGH PRESSURE WILL BUILD SOUTH ACROSS THE REGION WEDNESDAY WITH COOLER TEMPERATURES AND FAIR WEATHER RETURNING FOR THE REST OF THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... A WEAK SURFACE LOW ACROSS ILLINOIS WILL TRACK ACROSS KENTUCKY OVERNIGHT. AN ASSOCIATED WARM FRONT EXTENDS TO THE ENE OF THE LOW...TOWARD WESTERN NEW YORK. WITH VERY DRY AIR IN PLACE BENEATH 700 MB...EXPECT MOST LOCATIONS TO LARGELY REMAIN DRY OVERNIGHT. HOWEVER...RADAR DOES SHOW SOME SHOWERS ACROSS SOUTHERN ONTARIO FROM PORT HURON TO LONDON...WITH WHATEVER DOES HOLD TOGETHER WITH THIS LIKELY TO CLIP WESTERN PORTIONS OF THE SOUTHERN TIER THIS EVENING. THE HRRR IS LATE...BUT APPEARS TO CAPTURE THIS EVENTUALLY...WITH THE GFS/RGEM/NAM HINTING AT THIS IN THE RH FIELDS MORE SO THAN THE QPF. BASED ON THE TRAJECTORY OF THE SHOWERS...WILL MAINTAIN CHANCE POPS IN SOUTHERNMOST PORTIONS OF THE CWA...WHILE TRIMMING THINGS BACK TO THE NORTH. MOSTLY CLOUDY SKIES THE FIRST HALF OF THE NIGHT WILL KEEP AREA TEMPERATURES QUITE A BIT WARMER TONIGHT THAN TUESDAY MORNINGS SUB- FREEZING READINGS. UPPER 30S FOR WESTERN NY AND THE FINGER LAKES AND LOW TO MID 30S FOR THE NORTH COUNTRY. SKIES SHOULD CLEAR FROM NW-SE LATE TONIGHT. ARCTIC HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY BEHIND THE DEPARTING LOW. 850MB TEMPS WEDNESDAY WILL DROP TO AROUND -3C WHICH WILL SUPPORT HIGH TEMPS ONLY REACHING INTO THE LOW 50S ACROSS WESTERN NY DESPITE MAINLY CLEAR SKIES. MORE CLOUDS OVER THE NORTH COUNTRY AND 850MB TEMPS CLOSER TO -4C/-5C WILL KEEP HIGH TEMPS LIMITED TO THE UPPER 40S/LOW 50S. WINDS WEDNESDAY WILL BECOME BREEZY IN THE AFTERNOON AS THE PRESSURE GRADIENT TIGHTENS WITH THE APPROACHING ARCTIC HIGH AND THE SURFACE LOW OVER THE MID-ATLANTIC COAST. NORTHWEST GUSTS MAY APPROACH 20 TO 25 MPH ACROSS THE NORTH COUNTRY AND SOUTHEAST OF THE LAKE. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... IT WILL BE SEASONABLY CHILLY DURING THIS PERIOD AS OUR REGION WILL REMAIN IN THE COLD SIDE OF A WEAKLY ESTABLISHED REX BLOCK. THIS LONGWAVE PATTERN WILL FEATURE A CUT OFF LOW OVER THE PLAINS THAT WILL BE TOPPED BY A HIGH AMPLITUDE RIDGE THAT WILL EXTEND NORTHWARDS PAST HUDSON BAY. WHILE THE UNDERLYING CUT OFF IS FORECAST TO PROGRESS EASTWARD ACROSS THE SOUTHERN STATES DURING THIS TIME FRAME...THE RIDGE WILL BE MUCH SLOWER IN ITS PROGRESSION ACROSS THE GREAT LAKES REGION. DOWNSTREAM FROM THE AFOREMENTIONED RIDGE WILL BE A FAIRLY SHARP TROUGH THAT WILL BE CENTERED OVER QUEBEC AND NEW ENGLAND. THIS WILL HOLD OUR TEMPERATURES AT OR SLIGHTLY BELOW NORMAL FOR THIS PERIOD... WHILE AN EXPANSIVE SFC HIGH WILL KEEP THE VAST MAJORITY OF THE REGION PRECIPITATION FREE. ALL IN ALL...A PRETTY `VANILLA` PERIOD. A ROBUST SHORTWAVE WILL DROP INTO THE BASE OF THE EASTERN CANADIAN TROUGH WEDNESDAY NIGHT...AND AS THIS BUNDLE OF ENERGY CROSSES THE NORTH COUNTRY...THERE MAY BE ENOUGH LOW LEVEL MOISTURE AND LIFT PRESENT TO POSSIBLY GENERATE A COUPLE WIDELY SEPARATED RAIN OR WET SNOW SHOWERS. WILL USE LOW CHC POPS TO COVER THIS MINIMAL POSSIBILITY. THE REMAINDER OF THE FORECAST AREA WILL BE PCPN FREE...BUT WITH ANOTHER FROST OR FREEZE. H85 TEMPS OF -8C WILL HELP TO PUSH OVERNIGHT LOWS BACK DOWN INTO THE 20S AND LOWER 30S. A MASSIVE AREA OF HIGH PRESSURE WILL EASE SOUTHWARDS ACROSS THE UPPER GREAT LAKES ON THURSDAY. THIS WILL PROVIDE OUR FORECAST AREA WITH PARTLY/MSTLY SUNNY SKIES...ALTHOUGH WITH H85 TEMPS STILL COLDER THAN -4C AND SOME RESIDUAL LOW LEVEL MOISTURE IN PLACE...SITES AWAY FROM THE LAKES MAY EXPERIENCE A FEW HOURS OF BROKEN STRATO-CU CLOUD COVER. IT WILL BE A COOL DAY AS WELL WITH MAX TEMPS STRUGGLING TO REACH NORMAL EARLY APRIL VALUES. AS THE LARGE SFC HIGH SETTLES OVER THE ENTIRE GREAT LAKES REGION THURSDAY NIGHT...THE PRESSURE GRADIENT WILL WEAKEN SO THAT VERY GOOD RADIATIONAL COOLING WILL BECOME ESTABLISHED UNDER CLEAR SKIES. THIS WILL SET THE STAGE FOR YET ANOTHER WIDESPREAD FREEZE AWAY FROM THE LAKES. OVERNIGHT LOWS WILL RANGE FROM THE FREEZING MARK NEAR THE LAKE SHORES TO 20 TO 25 IN THE SRN TIER VALLEYS AND EAST OF LAKE ONTARIO. FOR FRIDAY AND FRIDAY NIGHT...A H5 RIDGE WILL SLOWLY PUSH ACROSS THE UPPER GREAT LAKES WHILE THE CORE OF THE SFC HIGH WILL DRIFT TO BE ABOUT LAKE ERIE. THIS WILL PROVIDE OUR FORECAST AREA WITH NEARLY CLOUD FREE SKIES AND SEASONABLE TEMPERATURES. THAT WILL INCLUDE ANOTHER FROSTY NIGHT FRIDAY NIGHT...ESPECIALLY FOR THE SITES WELL AWAY FROM THE LAKES. && .LONG TERM /SATURDAY THROUGH TUESDAY/... FAIR...SEASONABLY MILD WEATHER AT THE START OF THIS PERIOD WILL GIVE WAY TO CHILLY UNSETTLED CONDITIONS AS TROUGHINESS OVER THE HIGH PLAINS OF SASKATCHEWAN WILL DIG SOUTHEAST ACROSS THE GREAT LAKES REGION. THIS FEATURE WILL EVENTUALLY CARVE ITS WAY INTO A LONGWAVE TROUGH OVER THE EASTERN HALF OF NORTH AMERICA. AS A RESULT... TEMPERATURES WILL DEFINITELY TREND DOWNWARDS DURING THIS PERIOD WITH BELOW NORMAL MERCURY READINGS BECOMING ESTABLISHED BY TUESDAY. THESE VALUES WILL LIKELY PERSIST THROUGH AT LEAST MID WEEK. SATURDAY WILL BE THE NICEST DAY OF THIS PERIOD...BY FAR...AS STRONG HIGH PRESSURE WILL DRIFT ACROSS OUR FORECAST AREA. SUN FILLED SKIES WILL BOOST SFC TEMPS INTO THE UPPER 50S TO LOWER 60S FOR MOST AREAS WITH EVEN WARMER CONDITIONS EXPECTED IN THE GENESEE VALLEY. AS THE HIGH MOVES OFF THE EAST COAST SUNDAY NIGHT...A PACIFIC BASED COLD FRONT WILL PUSH ACROSS THE UPPER GREAT LAKES AND MID WEST. THIS FRONT WILL MOVE ACROSS OUR AREA ON SUNDAY...AND WHILE THE VAST MAJORITY OF THE DAY SHOULD BE RAIN FREE...THERE WILL PROBABLY BE A 3 HOUR WINDOW OF SCT SHOWER ACTIVITY. SHORTWAVE RIDGING IN THE WAKE OF THE FRONT SHOULD PROVIDE US WITH DRY WEATHER SUNDAY NIGHT...BUT ADDITIONAL ENERGY FEEDING INTO THE TROUGH WILL ENCOURAGE THE SYSTEM TO DIG ITS WAY ACROSS LOWER ONTARIO. FALLING HGTS AND COLD ADVECTION FROM THIS PROCESS COULD SUPPORT SOME MORE SHOWERS...MAINLY IN THE AFTERNOON AND MONDAY NIGHT. ON TUESDAY...A DEEP LONGWAVE TROUGH WILL BE ANCHORED IN THE VCNTY OF NEW YORK STATE. THIS WILL KEEP COOL UNSETTLED WEATHER OVER OUR REGION WITH HIGH TEMPERATURES NOT MAKING IT OUT OF THE 40S. && .AVIATION /23Z TUESDAY THROUGH SUNDAY/... A FRONTAL BOUNDARY EXTENDING NORTHEAST OF LOW PRESSURE PASSING TO THE SOUTH WILL GET PUSHED TO THE SOUTH...ALLOWING FOR SKIES TO CLEAR LATER TONIGHT. UNTIL THEN...EXPECT MAINLY BKN CLOUDS WITH CIGS WELL ABOVE 3000 FT. THERE WILL BE SCATTERED SHOWERS IN THE VICINITY OF JHW DURING THE EVENING HOURS...OTHERWISE EXPECT TAF LOCATIONS TO REMAIN DRY. SKIES SHOULD SCATTER OUT LATE TONIGHT AND INTO WEDNESDAY MORNING...WITH CONTINUED VFR CONDITIONS. WINDS WILL PICK UP WITH DAYTIME MIXING...WITH GUSTS IN THE 20 TO 25 KT RANGE LIKELY. CLOUDS ALSO MAY INCREASE TO SCT-BKN...BUT WILL LIKELY REMAIN IN THE VFR FLIGHT CATEGORY. AN UPPER LEVEL IMPULSE WILL DROP ACROSS EASTERN NEW YORK WEDNESDAY AFTERNOON...WHICH MAY SPARK A STRAY SHOWER AT ART. OUTLOOK... WEDNESDAY NIGHT...MAINLY VFR. THURSDAY AND FRIDAY...VFR. SATURDAY...VFR. && .MARINE... A WEAK LOW WILL PASS JUST SOUTH OF NEW YORK STATE TONIGHT THEN SETTLE OFF THE EAST COAST BY WEDNESDAY MORNING WITH NO IMPACT TO WIND AND WAVE CONDITIONS ACROSS THE LAKES. A MODEST NORTH TO NORTHWEST FLOW OF COLDER AIR WILL SET UP ACROSS THE LAKES WEDNESDAY AND THURSDAY AS ARCTIC HIGH PRESSURE BUILDS SOUTH ACROSS NY. THE RESULTING WINDS AND WAVES MAY APPROACH SMALL CRAFT ADVISORY LEVELS ALONG THE EAST AND SOUTH SHORES OF LAKE ONTARIO IN THE AFTERNOON. && .CLIMATE... THE MONTHLY CLM CLIMATE SUMMARIES HAVE BEEN UPDATED TO INCLUDE THE NARRATIVE SECTION AT THE BOTTOM. THEY ARE AVAILABLE ON OUR WEBSITE UNDER THE CLIMATE SECTION. HERE ARE SOME TIDBITS BELOW... MARCH 2012 IS A MONTH FOR THE RECORD BOOKS AS AN UNSEASONABLE AND PERSISTENT WARM PATTERN REMAINED ACROSS THE EASTERN US. FOR BUFFALO MARCH FINISHED WITH AN AVERAGE TEMPERATURE OF 47.4 DEGREES WHICH IS +13.4 DEGREES ABOVE NORMAL...AND 2.9 DEGREES WARMER THAN THE PREVIOUS WARMEST MARCH. THIS 2.9 DEGREES IS THE LARGEST SEPARATION BETWEEN WARMEST...AND 2ND WARMEST FOR ANY MONTH IN BUFFALO...WITH THE NOW SECOND LARGEST SEPARATION 2.6 DEGREES FOR THE TWO WARMEST MONTHS OF SEPTEMBER. FOR ROCHESTER MARCH FINISHED WITH AN AVERAGE TEMPERATURE OF 47.3 DEGREES WHICH IS +13.0 DEGREES ABOVE NORMAL...AND 3.5 DEGREES WARMER THAN THE PREVIOUS WARMEST MARCH. THIS 3.5 DEGREES IS THE LARGEST SEPARATION BETWEEN WARMEST...AND 2ND WARMEST FOR ANY MONTH IN ROCHESTER WITH THE NOW SECOND LARGEST SEPARATION 3.1 DEGREES FOR THE TWO WARMEST MONTHS OF SEPTEMBER. FOR BOTH CITIES MARCH FINISHED WARMER THAN THE NORMAL APRIL. THE 47.4 DEGREES AVERAGE MARCH 2012 TEMPERATURE IN BUFFALO WAS 1.5 DEGREES WARMER THAN THE NORMAL APRIL VALUE. FOR ROCHESTER THE 47.3 DEGREES AVERAGE MARCH 2012 TEMPERATURE WAS 1.0 DEGREES WARMER THAN THE NORMAL APRIL VALUE. BUFFALO ESTABLISHED SEVEN NEW RECORD HIGH TEMPERATURES IN MARCH 2012...WHILE ROCHESTER ESTABLISHED THREE NEW RECORD HIGH TEMPERATURES. BOTH CITIES SET 5 NEW RECORD WARM MINIMUM TEMPERATURES. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...SMITH NEAR TERM...APFFEL/SMITH SHORT TERM...RSH LONG TERM...RSH AVIATION...APFFEL MARINE...SMITH CLIMATE...THOMAS/HITCHCOCK
AREA FORECAST DISCUSSION
NWS BUFFALO NY
657 AM EDT MON APR 2 2012 .SYNOPSIS... SKIES WILL GRADUALLY CLEAR TODAY AS HIGH PRESSURE BUILDS ACROSS THE REGION FROM CANADA. TEMPERATURES WILL DROP BELOW FREEZING ACROSS THE REGION UNDERNEATH THE HIGH PRESSURE RIDGE. THEN A WEAK SYSTEM WILL BRING A SMALL CHANCE OF SHOWERS TUESDAY BEFORE DRY WEATHER RETURNS FOR THE REST OF THE WEEK ALONG WITH SEASONABLE TEMPERATURES. && .NEAR TERM /THROUGH TONIGHT/... FOR TODAY...THE MAIN FORECAST CHALLENGE WILL BE DETERMINING EXACTLY WHEN SKIES WILL CLEAR OUT. AT DAYBREAK SKIES ARE VARIABLE...WITH PATCHES OF LOW CLOUDS AND CLEARING. THERE IS ALSO SOME PATCHY FOG IN AREAS WHICH HAVE CLEARED. EXPECT LAKE ONTARIO AND THE IMMEDIATE SHORELINE TO STAY CLEAR. A BIT SOUTH OF THIS...THERE IS STILL QUITE A BIT OF MOISTURE...SO CLOUDS MAY FILL BACK IN TO SOME EXTENT THROUGH THE MORNING HOURS...BEFORE A MORE COMPREHENSIVE CLEARING THIS AFTERNOON. THE NAM/GFS HAVE BEEN TOO QUICK TO CLEAR THINGS OUT...WITH THE RUC BUFKIT SHOWING LINGERING MOISTURE UNTIL LATE MORNING WHEN DRIER AIR BUILDS IN. EXPECT HIGHS TO RANGE FROM THE UPPER 40S TO AROUND 50. FOR TONIGHT...HIGH PRESSURE WILL BUILD ACROSS THE REGION...AND WITH DRIER AIR IN PLACE...SEE NO REASON WHY WE WILL NOT EXPERIENCE GOOD RADIATIONAL COOLING CONDITIONS. WITH CONFIDENCE IN RADIATIONAL COOLING...WILL FAVOR THE COLDER MOS NUMBERS OVER BIAS CORRECTED GRIDS FOR LOWS TONIGHT. THIS SHOULD RESULT IN FREEZING TEMPERATURES ACROSS THE REGION...WITH MANY SPOTS FURTHER FROM THE LAKE SHORE LIKELY TO DROP INTO THE 20S. BECAUSE OF THIS...WILL TRANSITION THE FREEZE WATCH INTO A FREEZE WARNING. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AFTER A COLD AND FROSTY START TO THE DAY...TUESDAY WILL FEATURE A GRADUAL INCREASE IN MID AND HIGH LEVEL CLOUDS AS A WEAK SURFACE TROUGH MOVES EAST TOWARD THE LOWER GREAT LAKES. THE MODELS CONTINUE TO SUGGEST THAT THE DEEPEST LOW LEVEL MOISTURE WILL REMAIN WELL SOUTH OF NEW YORK STATE...WHILE THE BEST UPPER LEVEL SUPPORT STAYS TO OUR NORTH IN THE VICINITY OF THE DIGGING UPPER LEVEL TROUGH OVER ONTARIO PROVINCE. THIS CONFIRMS THE TREND OF PREVIOUS MODEL RUNS OF A DRY FORECAST. WARM ADVECTION IN ADVANCE OF THE TROUGH WILL BRING SOME MODERATION IN TEMPERATURES ON TUESDAY...WITH HIGH TEMPERATURES LIKELY RANGING FROM THE LOWER TO MID 50S ACROSS THE NORTH COUNTRY TO THE LOWER 60S ACROSS THE SOUTHERN TIER AND UPPER GENESEE VALLEY. AS THE TROUGH CROSSES THE AREA TUESDAY NIGHT...IT LOOKS LIKE IT WILL TAP SOME OF THE DEEPER MOISTURE TO OUR SOUTH AND PRODUCE A FEW SHOWERS. MODEST COOL AIR ADVECTION WILL TAKE PLACE BEHIND THE TROUGH AND ALLOW TEMPERATURES TO INTO THE 30S. THIS COULD RESULT IN A MIX OF RAIN AND SNOW SHOWERS FOR A BRIEF TIME ACROSS THE NORTH COUNTRY WHERE TEMPERATURES ALOFT WILL BE COOLING FASTER. ON WEDNESDAY...THE UPPER LEVEL TROUGH IS FORECAST DEEPEN OVER SOUTHERN QUEBEC AND NORTHERN NEW ENGLAND...WITH A FAIRLY SIGNIFICANT VORT LOBE DROPPING SOUTHEAST ACROSS CENTRAL AND EASTERN NEW YORK. WITH JUST ENOUGH MOISTURE IN PLACE...THE LIFT ASSOCIATED WITH THIS FEATURE MAY BE JUST ENOUGH TO SQUEEZE OUT A FEW SHOWERS ACROSS THE NORTH COUNTRY AND PERHAPS THE EASTERN FINGER LAKES. FARTHER TO THE WEST...A DRIER AIRMASS WILL BE IN PLACE. THIS SHOULD RESULT IN MAINLY DRY CONDITIONS. ONGOING COLD AIR ADVECTION ASSOCIATED WITH THE DEEPENING UPPER LEVEL TROUGH WILL RESULT IN A NOTICEABLY COOLER AND MORE SEASONABLE DAY THAN TUESDAY...WITH DAYTIME HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S. ANY SHOWERS SHOULD THEN DIE OUT FAIRLY QUICKLY WITH THE DEPARTURE OF THE VORT LOBE AND LOSS OF HEATING WEDNESDAY EVENING...LEAVING BEHIND A DRY BUT ALSO CHILLY NIGHT...WITH WIDESPREAD LOWS IN THE UPPER 20S TO LOWER 30S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... IN THE EXTENDED PERIOD...THE GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE MAIN UPPER LEVEL TROUGH WILL LINGER ACROSS THE REGION INTO FRIDAY...BEFORE FINALLY SLIDING OFF TO THE EAST NEXT WEEKEND AND ALLOWING UPPER-LEVEL RIDGING TO GRADUALLY BUILD EAST FROM THE UPPER MIDWEST/ WESTERN GREAT LAKES. MEANWHILE AT THE SURFACE...HIGH PRESSURE AND DRIER AIR WILL CONTINUE TO BUILD SOUTHEAST FROM CENTRAL CANADA... EVENTUALLY CRESTING ACROSS THE AREA ON SUNDAY. UNDER THIS PATTERN...DRY AND SEASONABLY COOL WEATHER SHOULD REMAIN THE GENERAL RULE FOR BOTH THURSDAY AND FRIDAY. TEMPERATURES SHOULD AVERAGE OUT CLOSE TO OR A LITTLE BELOW SEASONAL NORMALS BOTH DAYS...WITH A WIDESPREAD FROST OR FREEZE POSSIBLE BOTH THURSDAY AND FRIDAY NIGHTS. THEREAFTER...DRY WEATHER SHOULD CONTINUE THROUGH NEXT WEEKEND... ALONG WITH A WARMING TREND AS RIDGING BUILDS ACROSS THE AREA AT ALL LEVELS. WITH THE MEDIUM RANGE GUIDANCE CONTINUING TO SHOW BOTH RUN-TO-RUN AND MODEL-TO-MODEL INCONSISTENCIES WITH THE EXTENT OF THIS WARMING TREND...FOR NOW WILL CONTINUE TO AIM A BIT ON THE CONSERVATIVE SIDE FOR TEMPS...INDICATING HIGHS REACHING INTO THE MID AND UPPER 50S BY SATURDAY...AND THE UPPER 50S TO LOWER 60S BY SUNDAY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... THROUGH THIS MORNING...MOISTURE STILL LINGERS IN THE BOUNDARY LAYER. THROUGH 15Z MAY SEE A BRIEF LOWERING OF CONDITIONS IN CIGS/VSBY WITH SUNRISE...BUT EXPECT DRIER AIR TO MOVE IN LATE MORNING...WHICH WILL SCATTER OUT CLOUDS...GIVING WAY TO SKC THIS AFTERNOON. VFR CONDITIONS TONIGHT UNDER A STRONG HIGH PRESSURE RIDGE. OUTLOOK... TUESDAY...VFR. TUESDAY NIGHT...VFR/MVFR WITH CHANCE SHOWERS. WEDNESDAY...MAINLY VFR WITH CHANCE SHOWERS ACROSS THE NORTH COUNTRY. THURSDAY AND FRIDAY...VFR. && .MARINE... NW WINDS AROUND 15 KTS ON THE EASTERN HALF OF LAKE ONTARIO WILL RESULT IN MARGINAL SMALL CRAFT CONDITIONS. STRONGEST FLOW WILL BE THROUGH 12Z...SO WILL HANG ONTO THE SCA HEADLINE ON THE EASTERN HALF OF THE LAKE FOR NOW...BUT MAY BE ABLE TO DROP EARLY IF WINDS DO NOT INCREASE A BIT. AFTER THIS...HIGH PRESSURE BUILDS IN...WITH A FAIRLY EXTENDED PERIOD OF GENERALLY LIGHT WINDS ON THE LAKES EXPECTED. PERSISTENT RIDGING MAY KEEP THE WATERS FREE OF HEADLINES THROUGH THE END OF THE WEEK. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR NYZ001>006-010-011-013-014-019-085. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR LOZ043- 044. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...TJP LONG TERM...JJR AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
335 AM EDT MON APR 2 2012 .SYNOPSIS... SKIES WILL GRADUALLY CLEAR TODAY AS HIGH PRESSURE BUILDS ACROSS THE REGION FROM CANADA. TEMPERATURES WILL DROP BELOW FREEZING ACROSS THE REGION UNDERNEATH THE HIGH PRESSURE RIDGE. THEN A WEAK SYSTEM WILL BRING A SMALL CHANCE OF SHOWERS TUESDAY BEFORE DRY WEATHER RETURNS FOR THE REST OF THE WEEK ALONG WITH SEASONABLE TEMPERATURES. && .NEAR TERM /THROUGH TONIGHT/... FOR TODAY...THE MAIN FORECAST CHALLENGE WILL BE DETERMINING EXACTLY WHEN SKIES WILL CLEAR OUT. WITH HIGH PRESSURE SLOWLY BUILDING FROM THE WEST...SKIES HAVE QUICKLY CLEARED TO THE NORTH...WITH IR SATELLITE SHOWING A NORTH TO SOUTH CLEARING. HOWEVER...THE 11U-3.9U SATELLITE PRODUCT SHOWS LOW CLOUDS BUILDING BACK BEHIND THIS APPARENT CLEARING LINE...WHICH WILL SLOW THE CLEARING PROGRESSION. WHILE NAM/GFS MODEL GUIDANCE WANTS US TO CLEAR OUT BY 09Z OR SO...GIVEN THE UPSLOPING NORTHERLY FLOW AND -5C 850 MB TEMPS EXPECT LOW CLOUDS TO LINGER INTO THE MORNING HOURS IN MOST LOCATIONS SOUTH OF LAKE ONTARIO...AND PERHAPS INTO THE AFTERNOON ACROSS HIGHER TERRAIN IN THE SOUTHERN TIER. THIS IS ALSO CONSISTENT WITH SEVERAL RECENT NORTHERLY FLOW EVENTS...WHERE MODEL GUIDANCE WAS SIMPLY TOO QUICK TO CLEAR OUT CLOUDS. NOTE RECENT RUNS OF THE RUC SEEM TO CAPTURE THIS LOW MOISTURE NICELY...SO IN TERMS OF SKY COVER...USED A RUC WEIGHTED BEND FOR TIMING THE CLEARING. THIS SAID...DRIER AIR SHOULD EVENTUALLY WIN OUT...WITH ABUNDANT SUNSHINE LIKELY BY THIS AFTERNOON. TEMPERATURES SHOULD RISE INTO THE UPPER 40S TO AROUND 50 TODAY...ASSUMING THAT CLOUDS CLEAR OUT EARLY ENOUGH FOR SOME SIGNIFICANT SUNSHINE DURING THE AFTERNOON HOURS. ALSO...PATCHY FOG WILL LIKELY DEVELOP IN AREAS WHICH DO CLEAR THROUGH EARLY THIS MORNING...WITH THE BEST CHANCE FOR MORNING FOG NEAR THE LAKE ONTARIO SHORELINE. FOR TONIGHT...HIGH PRESSURE WILL BUILD ACROSS THE REGION...AND WITH DRIER AIR IN PLACE...SEE NO REASON WHY WE WILL NOT EXPERIENCE GOOD RADIATIONAL COOLING CONDITIONS. WITH CONFIDENCE IN RADIATIONAL COOLING...WILL FAVOR THE COLDER MOS NUMBERS OVER BIAS CORRECTED GRIDS FOR LOWS TONIGHT. THIS SHOULD RESULT IN FREEZING TEMPERATURES ACROSS THE REGION...WITH MANY SPOTS FURTHER FROM THE LAKE SHORE LIKELY TO DROP INTO THE 20S. BECAUSE OF THIS...WILL TRANSITION THE FREEZE WATCH INTO A FREEZE WARNING. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AFTER A COLD AND FROSTY START TO THE DAY...TUESDAY WILL FEATURE A GRADUAL INCREASE IN MID AND HIGH LEVEL CLOUDS AS A WEAK SURFACE TROUGH MOVES EAST TOWARD THE LOWER GREAT LAKES. THE MODELS CONTINUE TO SUGGEST THAT THE DEEPEST LOW LEVEL MOISTURE WILL REMAIN WELL SOUTH OF NEW YORK STATE...WHILE THE BEST UPPER LEVEL SUPPORT STAYS TO OUR NORTH IN THE VICINITY OF THE DIGGING UPPER LEVEL TROUGH OVER ONTARIO PROVINCE. THIS CONFIRMS THE TREND OF PREVIOUS MODEL RUNS OF A DRY FORECAST. WARM ADVECTION IN ADVANCE OF THE TROUGH WILL BRING SOME MODERATION IN TEMPERATURES ON TUESDAY...WITH HIGH TEMPERATURES LIKELY RANGING FROM THE LOWER TO MID 50S ACROSS THE NORTH COUNTRY TO THE LOWER 60S ACROSS THE SOUTHERN TIER AND UPPER GENESEE VALLEY. AS THE TROUGH CROSSES THE AREA TUESDAY NIGHT...IT LOOKS LIKE IT WILL TAP SOME OF THE DEEPER MOISTURE TO OUR SOUTH AND PRODUCE A FEW SHOWERS. MODEST COOL AIR ADVECTION WILL TAKE PLACE BEHIND THE TROUGH AND ALLOW TEMPERATURES TO INTO THE 30S. THIS COULD RESULT IN A MIX OF RAIN AND SNOW SHOWERS FOR A BRIEF TIME ACROSS THE NORTH COUNTRY WHERE TEMPERATURES ALOFT WILL BE COOLING FASTER. ON WEDNESDAY...THE UPPER LEVEL TROUGH IS FORECAST DEEPEN OVER SOUTHERN QUEBEC AND NORTHERN NEW ENGLAND...WITH A FAIRLY SIGNIFICANT VORT LOBE DROPPING SOUTHEAST ACROSS CENTRAL AND EASTERN NEW YORK. WITH JUST ENOUGH MOISTURE IN PLACE...THE LIFT ASSOCIATED WITH THIS FEATURE MAY BE JUST ENOUGH TO SQUEEZE OUT A FEW SHOWERS ACROSS THE NORTH COUNTRY AND PERHAPS THE EASTERN FINGER LAKES. FARTHER TO THE WEST...A DRIER AIRMASS WILL BE IN PLACE. THIS SHOULD RESULT IN MAINLY DRY CONDITIONS. ONGOING COLD AIR ADVECTION ASSOCIATED WITH THE DEEPENING UPPER LEVEL TROUGH WILL RESULT IN A NOTICEABLY COOLER AND MORE SEASONABLE DAY THAN TUESDAY...WITH DAYTIME HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S. ANY SHOWERS SHOULD THEN DIE OUT FAIRLY QUICKLY WITH THE DEPARTURE OF THE VORT LOBE AND LOSS OF HEATING WEDNESDAY EVENING...LEAVING BEHIND A DRY BUT ALSO CHILLY NIGHT...WITH WIDESPREAD LOWS IN THE UPPER 20S TO LOWER 30S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... IN THE EXTENDED PERIOD...THE GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE MAIN UPPER LEVEL TROUGH WILL LINGER ACROSS THE REGION INTO FRIDAY...BEFORE FINALLY SLIDING OFF TO THE EAST NEXT WEEKEND AND ALLOWING UPPER-LEVEL RIDGING TO GRADUALLY BUILD EAST FROM THE UPPER MIDWEST/ WESTERN GREAT LAKES. MEANWHILE AT THE SURFACE...HIGH PRESSURE AND DRIER AIR WILL CONTINUE TO BUILD SOUTHEAST FROM CENTRAL CANADA... EVENTUALLY CRESTING ACROSS THE AREA ON SUNDAY. UNDER THIS PATTERN...DRY AND SEASONABLY COOL WEATHER SHOULD REMAIN THE GENERAL RULE FOR BOTH THURSDAY AND FRIDAY. TEMPERATURES SHOULD AVERAGE OUT CLOSE TO OR A LITTLE BELOW SEASONAL NORMALS BOTH DAYS...WITH A WIDESPREAD FROST OR FREEZE POSSIBLE BOTH THURSDAY AND FRIDAY NIGHTS. THEREAFTER...DRY WEATHER SHOULD CONTINUE THROUGH NEXT WEEKEND... ALONG WITH A WARMING TREND AS RIDGING BUILDS ACROSS THE AREA AT ALL LEVELS. WITH THE MEDIUM RANGE GUIDANCE CONTINUING TO SHOW BOTH RUN-TO-RUN AND MODEL-TO-MODEL INCONSISTENCIES WITH THE EXTENT OF THIS WARMING TREND...FOR NOW WILL CONTINUE TO AIM A BIT ON THE CONSERVATIVE SIDE FOR TEMPS...INDICATING HIGHS REACHING INTO THE MID AND UPPER 50S BY SATURDAY...AND THE UPPER 50S TO LOWER 60S BY SUNDAY. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... THE MAIN CONCERN WILL BE LINGERING MVFR TO IFR CIGS. WITH HIGH PRESSURE BUILDING FROM THE WEST...SATELLITE SHOWS A GENERAL NORTH TO SOUTH CLEARING TREND. HOWEVER...THIS CLEARING LINE IS STALLING SOUTH OF LAKE ONTARIO...WHERE COLD TEMPS ALOFT AND UPSLOPING ARE THE LIKELY CULPRIT. NOTED NAM/GFS GUIDANCE IS TOO OPTIMISTIC WITH THIS...WITH THE RUC BUFKIT SOUNDING SUGGESTING THAT LOW CLOUDS WILL LINGER INTO THIS MORNING. OUTSIDE OF ART...WILL HEDGE MORE PESSIMISTIC WITH ALL TAFS WITH RESPECT TO THE CLEARING. ONE OTHER THING TO WATCH FOR...IS IF CLOUDS DO CLEAR...IT MAY QUICKLY BE REPLACED WITH FOG...OR A LOWER CLOUD DECK AS BOUNDARY LAYER TEMPS QUICKLY COOL TO THE DEW POINT. OTHERWISE...EXPECT CLOUDS TO SCATTER OUT IN THE LATE MORNING TO EARLY AFTERNOON TIMEFRAME AS DRIER AIR WORKS IN AND FINALLY WINS OUT. INCREASING CONFIDENCE IN VFR CONDITIONS MONDAY AFTERNOON AND MONDAY NIGHT. OUTLOOK... TUESDAY...VFR. TUESDAY NIGHT...VFR/MVFR WITH CHANCE SHOWERS. WEDNESDAY...MAINLY VFR WITH CHANCE SHOWERS ACROSS THE NORTH COUNTRY. THURSDAY AND FRIDAY...VFR. && .MARINE... NW WINDS AROUND 15 KTS ON THE EASTERN HALF OF LAKE ONTARIO WILL RESULT IN MARGINAL SMALL CRAFT CONDITIONS. STRONGEST FLOW WILL BE THROUGH 12Z...SO WILL HANG ONTO THE SCA HEADLINE ON THE EASTERN HALF OF THE LAKE FOR NOW...BUT MAY BE ABLE TO DROP EARLY IF WINDS DO NOT INCREASE A BIT. AFTER THIS...HIGH PRESSURE BUILDS IN...WITH A FAIRLY EXTENDED PERIOD OF GENERALLY LIGHT WINDS ON THE LAKES EXPECTED. PERSISTENT RIDGING MAY KEEP THE WATERS FREE OF HEADLINES THROUGH THE END OF THE WEEK. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR NYZ001>006-010-011-013-014-019-085. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR LOZ043- 044. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...TJP LONG TERM...JJR AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS BUFFALO NY
139 AM EDT MON APR 2 2012 .SYNOPSIS... WHILE STUBBORN LOW CLOUDINESS WILL BE FOUND ACROSS THE REGION EARLY TONIGHT...HIGH PRESSURE CENTERED OVER JAMES BAY WILL NOSE SOUTH AND THIS WILL EVENTUALLY CLEAR OUR SKIES LATE TONIGHT AND MONDAY. THE HIGH PRESSURE WILL BUILD ACROSS OUR REGION LATE MONDAY...AND THIS WILL SET THE STAGE FOR SEASONABLY COLD CONDITIONS MONDAY NIGHT WITH A HARD FREEZE LIKELY AWAY FROM THE LAKES. A WEAK SYSTEM WILL BRING A SMALL CHANCE OF SHOWERS TUESDAY BEFORE DRY WEATHER RETURNS FOR THE REST OF THE WEEK ALONG WITH SEASONABLE TEMPERATURES. && .NEAR TERM /THROUGH TODAY/... THROUGH 100 AM...11U-3.9U SATELLITE SHOWS LOW CLOUDS LINGERING BUILDING SOUTH OF LAKE ONTARIO...DESPITE THE BROAD CLEARING TREND TO THE NORTH. BASED ON THIS...EXPECT MOST LOCATIONS WHICH ARE CLOUDY TO REMAIN SO FOR MOST OF TONIGHT...WHICH WILL LIMIT RADIATIONAL COOLING. NUDGED UP TEMPS WHERE ITS CLOUDY...AND CONTINUE WITH A MENTION OF FOG...ESPECIALLY IN AREAS WHICH DO CLEAR WHERE FOG MAY FORM. WEAK LOW PRESSURE IN THE VCNTY OF CENTRAL PENNSYLVANIA WILL KEEP A WAVY FRONTAL BOUNDARY CLOSE ENOUGH TO OUR FORECAST AREA TO HOLD A WEALTH OF LOW LEVEL MOISTURE IN PLACE FOR THE BULK OF THE UPCOMING NIGHT. ONCE THE WAVE MOVES EAST...HIGH PRESSURE CENTERED OVER JAMES BAY WILL BUILD SOUTH OVER THE LOWER GREAT LAKES. WHILE THIS PROCESS WILL EVENTUALLY PROMOTE CLEARING...IT WILL TAKE SOME TIME. HAVE ALREADY SLOWED THE CLEARING TREND FOR THE OVERNIGHT...AND MAY HAVE TO DO THE SAME FOR MONDAY AS A NORTHERLY UPSLOPE FLOW WILL BE FOUND OVER THE REGION. AS WAS MENTIONED IN PREVIOUS DISCUSSIONS... THE PAST FEW SCENARIOS SIMILAR TO THIS HAVE SEEN CLOUDS HANG IN MUCH LONGER...AS MUCH AS 12-18 HOURS LONGER THAN MODEL FORECASTS. WITH CLOUD COVER MOST OF THE NIGHT...AND A LIGHT 5-8 MPH BREEZE...HAVE GONE TOWARD THE HIGH END OF MODEL GUIDANCE FOR OVERNIGHT LOWS. THE BREEZE AND CLOUD COVER WILL LIKELY PREVENT THE SURFACE FROM SATURATING...AND THUS PREVENT MUCH FROST FORMATION EVEN IF TEMPERATURES APPROACH FREEZING. WITH THIS IN MIND WILL NOT GO WITH ANY FROST HEADLINES FOR TONIGHT AND JUST MENTION SOME PATCHY LIGHT FROST IN THE FORECAST. IN TERMS OF TEMPERATURES ON MONDAY...850MB TEMPS AROUND -4C WILL KEEP TEMPS ON THE COOL SIDE WITH UPPER 40S TO AROUND 50 ACROSS LOWER ELEVATIONS (ASSUMING AN INCREASING AMOUNT SUNSHINE)...AND MID 40S HIGHER TERRAIN. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... MONDAY NIGHT...STRONG CANADIAN HIGH PRESSURE WILL RIDGE DIRECTLY OVER THE FORECAST AREA. PLENTIFUL DRY AIR AND LIGHT WINDS ASSOCIATED WITH THE SURFACE HIGH WILL PROVIDE IDEAL CONDITIONS FOR RADIATIONAL COOLING...ALLOWING TEMPERATURES TO FALL INTO THE MID 20S TO LOW 30S AREAWIDE...WITH SOME LOWER 20S EVEN POSSIBLE IN THE INTERIOR OF THE SOUTHERN TIER AND NORTH COUNTRY. AS OUR FROST/FREEZE PROGRAM IS NOW ACTIVE FOR ALL BUT CATTARAUGUS/ALLEGANY/WYOMING/JEFFERSON/LEWIS COUNTIES...WE WILL BE ISSUING A FREEZE WATCH FOR MONDAY NIGHT FOR MUCH OF OUR AREA IN COORDINATION WITH WFO BGM. TUESDAY AND TUESDAY NIGHT...A WEAK TROUGH OF LOW PRESSURE WILL SLOWLY DRIFT EAST FROM THE WESTERN GREAT LAKES...IN ASSOCIATION WITH A MODEST SHORTWAVE TROUGH SLIDING THROUGH THE PREVAILING NORTHWESTERLY FLOW ALOFT. MODEL GUIDANCE HAS CONTINUED TO TREND MARKEDLY SLOWER AND WEAKER WITH THIS FEATURE OVER THE PAST TWO DAYS...AND NOW SUGGESTS THAT THIS FEATURE WILL REMAIN FAR ENOUGH TO OUR WEST TO RESULT IN A LARGELY DRY DAY TUESDAY...FOLLOWED BY ONLY A BRIEF CHANCE OF SHOWERS TUESDAY EVENING AS THE MAIN TROUGH AXIS WORKS ACROSS THE AREA ALONG WITH ONLY LIMITED LIFT/MOISTURE. WITH THE ABOVE IN MIND...HAVE DROPPED POPS FOR TUESDAY TO SLIGHT CHANCE OR LESS...WITH ANY LOW-END CHANCE OF SHOWERS NOW CONFINED TO JUST TUESDAY EVENING. HAVE ALSO REMOVED ANY MENTION OF THUNDER GIVEN THE MORE UNFAVORABLE TIMING OF THIS SYSTEM AND THE UNIMPRESSIVE NATURE OF ITS ASSOCIATED LIFT/MOISTURE. WARM ADVECTION IN ADVANCE OF THE TROUGH WILL BRING SOME MODERATION IN TEMPS ON TUESDAY...WITH HIGH TEMPERATURES LIKELY RANGING FROM THE LOWER TO MID 50S ACROSS THE NORTH COUNTRY TO THE LOWER 60S ACROSS THE SOUTHERN TIER. MODEST COOL AIR ADVECTION BEHIND THE LOW WILL THEN HELP TO SEND TEMPERATURES BACK DOWN INTO THE MID AND UPPER 30S IN MOST PLACES TUESDAY NIGHT...WITH SOME LOWER 30S POSSIBLE EAST OF LAKE ONTARIO. ON WEDNESDAY...UPPER LEVEL TROUGHING WILL CONTINUE TO DIG ACROSS THE THE EASTERN GREAT LAKES AND NORTHEASTERN STATES...WITH A FAIRLY SIGNIFICANT VORT LOBE DROPPING SOUTHEAST ACROSS CENTRAL AND EASTERN NEW YORK. WITH JUST ENOUGH MOISTURE IN PLACE...THE LIFT ASSOCIATED WITH THIS FEATURE MAY BE JUST ENOUGH TO SQUEEZE OUT A FEW SHOWERS ACROSS THE NORTH COUNTRY AND PERHAPS THE EASTERN FINGER LAKES...WITH A DRIER AIRMASS OTHERWISE SUPPORTING MAINLY DRY CONDITIONS ACROSS THE REMAINDER OF THE FORECAST AREA. ONGOING COLD AIR ADVECTION ASSOCIATED WITH THE DEEPENING TROUGH WILL RESULT IN A NOTICEABLY COOLER AND MORE SEASONABLE DAY THAN TUESDAY...WITH DAYTIME HIGH TEMPERATURES REACHING THE MID 40S TO LOWER 50S. ANY SHOWERS SHOULD THEN DIE OUT FAIRLY QUICKLY WITH THE DEPARTURE OF THE VORT LOBE AND LOSS OF HEATING WEDNESDAY EVENING...LEAVING BEHIND A QUIET/DRY BUT ALSO CHILLY NIGHT...WITH WIDESPREAD LOWS IN THE UPPER 20S TO LOWER 30S ANTICIPATED. && .LONG TERM /THURSDAY THROUGH SUNDAY/... IN THE EXTENDED PERIOD...THE GUIDANCE REMAINS IN GOOD AGREEMENT THAT THE MAIN UPPER LEVEL TROUGH WILL LINGER ACROSS THE REGION INTO FRIDAY...BEFORE FINALLY SLIDING OFF TO THE EAST NEXT WEEKEND AND ALLOWING UPPER-LEVEL RIDGING TO GRADUALLY BUILD EAST FROM THE UPPER MIDWEST/ WESTERN GREAT LAKES. MEANWHILE AT THE SURFACE...HIGH PRESSURE AND DRIER AIR WILL CONTINUE TO BUILD SOUTHEAST FROM CENTRAL CANADA... EVENTUALLY CRESTING ACROSS THE AREA ON SUNDAY. UNDER THIS PATTERN...DRY AND SEASONABLY COOL WEATHER SHOULD REMAIN THE GENERAL RULE FOR BOTH THURSDAY AND FRIDAY. TEMPERATURES SHOULD AVERAGE OUT CLOSE TO OR A LITTLE BELOW SEASONAL NORMALS BOTH DAYS...WITH A WIDESPREAD FROST OR FREEZE POSSIBLE BOTH THURSDAY AND FRIDAY NIGHTS. THEREAFTER...DRY WEATHER SHOULD CONTINUE THROUGH NEXT WEEKEND... ALONG WITH A WARMING TREND AS RIDGING BUILDS ACROSS THE AREA AT ALL LEVELS. WITH THE MEDIUM RANGE GUIDANCE CONTINUING TO SHOW BOTH RUN-TO-RUN AND MODEL-TO-MODEL INCONSISTENCIES WITH THE EXTENT OF THIS WARMING TREND...FOR NOW WILL CONTINUE TO AIM A BIT ON THE CONSERVATIVE SIDE FOR TEMPS...INDICATING HIGHS REACHING INTO THE MID AND UPPER 50S BY SATURDAY...AND THE UPPER 50S TO LOWER 60S BY SUNDAY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... THE MAIN CONCERN WILL BE LINGERING MVFR TO IFR CIGS. WITH HIGH PRESSURE BUILDING FROM THE WEST...SATELLITE SHOWS A GENERAL NORTH TO SOUTH CLEARING TREND. HOWEVER...THIS CLEARING LINE IS STALLING SOUTH OF LAKE ONTARIO...WHERE COLD TEMPS ALOFT AND UPSLOPING ARE THE LIKELY CULPRIT. NOTED NAM/GFS GUIDANCE IS TOO OPTIMISTIC WITH THIS...WITH THE RUC BUFKIT SOUNDING SUGGESTING THAT LOW CLOUDS WILL LINGER INTO THIS MORNING. OUTSIDE OF ART...WILL HEDGE MORE PESSIMISTIC WITH ALL TAFS WITH RESPECT TO THE CLEARING. ONE OTHER THING TO WATCH FOR...IS IF CLOUDS DO CLEAR...IT MAY QUICKLY BE REPLACED WITH FOG...OR A LOWER CLOUD DECK AS BOUNDARY LAYER TEMPS QUICKLY COOL TO THE DEW POINT. OTHERWISE...EXPECT CLOUDS TO SCATTER OUT IN THE LATE MORNING TO EARLY AFTERNOON TIMEFRAME AS DRIER AIR WORKS IN AND FINALLY WINS OUT. INCREASING CONFIDENCE IN VFR CONDITIONS MONDAY AFTERNOON AND MONDAY NIGHT. OUTLOOK... TUESDAY...VFR. TUESDAY NIGHT...VFR/MVFR WITH CHANCE SHOWERS. WEDNESDAY...MAINLY VFR WITH CHANCE SHOWERS ACROSS THE NORTH COUNTRY. THURSDAY AND FRIDAY...VFR. && .MARINE... LIGHT WINDS THIS EVENING WILL SHIFT TO THE NORTH AND NORTHEAST OVERNIGHT AS HIGH PRESSURE WILL PRESS SOUTH FROM JAMES BAY. THESE WINDS WILL FRESHEN OVERNIGHT THOUGH AS THE PRESSURE GRADIENT WILL TIGHTEN UP IN ADVANCE OF THE AFOREMENTIONED CANADIAN HIGH PRESSURE SYSTEM. THIS WILL RESULT IN MARGINAL SMALL CRAFT ADVISORY CONDITIONS FOR A FEW HOURS LATE TONIGHT THROUGH MONDAY MORNING ALONG THE SOUTH SHORE OF LAKE ONTARIO. LAKE ERIE WILL ALSO BECOME CHOPPY LATER TONIGHT THROUGH MONDAY MORNING SOUTHWEST OF DUNKIRK IN NORTHEAST WINDS...BUT FOR NOW WILL HOLD THIS AREA AT 2-4 FEET WITHOUT ANY HEADLINE. HIGH PRESSURE WILL BUILD OVER THE LOWER LAKES LATER MONDAY AND MONDAY NIGHT WITH DIMINISHING WIND AND WAVES. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...FREEZE WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR NYZ001>006-010-011-013-014-019-085. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR LOZ042>044. && $$ SYNOPSIS...HITCHCOCK/RSH NEAR TERM...APFFEL/HITCHCOCK/RSH SHORT TERM...JJR LONG TERM...JJR AVIATION...APFFEL MARINE...HITCHCOCK/RSH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1045 PM EDT TUE APR 3 2012 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTH THROUGH THE CAROLINAS WEDNESDAY NIGHT AND EARLY THURSDAY FOLLOWED BY A REINFORCING SHOT OF COLD AIR FRIDAY NIGHT INTO SATURDAY AS STRONG HIGH PRESSURE BUILDS DOWN ACROSS THE CAROLINAS. HIGH PRESSURE WILL WEAKEN AS IT MOVES OFFSHORE ON MONDAY AS YET ANOTHER COLD FRONT APPROACHES FROM THE NORTHWEST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM...HRRR MODEL OUTPUT INDICATES THE CLUSTER OF CONVECTION ACROSS THE CENTRAL PORTIONS OF THE CAROLINAS IS PROGGED TO MAKE SLOW EASTWARD PROGRESS...POSSIBLY REACHING THE WESTERN EDGE OF THE ILM CWA AT OR UP TO A FEW HRS AFTER MIDNIGHT. BY THAT TIME...INSTABILITY WILL BE LACKING ESPECIALLY HAVING TRACKED INTO AN ATM ALREADY NONCONDUCIVE FOR TSRA ACTIVITY TO START WITH. WEAK MID LEVEL VORTICIES OVER THE WEST/CENTRAL CAROLINAS ARE AIDING THE FORCING NEEDED TO SUSTAIN THIS CONVECTION AS IT APPROACHES THE ILM CWA FROM THE WEST DURING THE OVERNIGHT. AS INDICATED B4...HRRR SFC BASED CAPE BASICALLY NON-EXISTENT ACROSS THE ILM CWA BY THE TIME THIS ACTIVITY REACHES THE OUTSKIRTS OF THE ILM CWA. WITH THIS SAID...WILL CONTINUE CURRENT TREND WITH ONLY LOW CHANCE POPS OVERNIGHT...MAINLY ALONG THE WEST THROUGH NORTHWEST OUTLINE OF THE ILM CWA. DUE TO LATEST SAT IMAGERY TRENDS AND SFC OBS...CURRENT FORECAST OF SKY CONDITIONS LOOKS AOK WITH NO CHANGES NEEDED. FOR MIN TEMP FORECAST AND OVERNIGHT DEWPOINTS...SOME TWEAKING UPWARDS NEEDED BY 1 TO AS MUCH AS 3 DEGREES BASED ON LATEST SFC OBS AND LAPS/MSAS ANALYSIS TRENDS...AND WITH SOME AID FROM THE LATEST RUNS OF THE HRRR AND RUC. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...VERY LOW AMPLITUDE TROUGHINESS/WNW FLOW MOVES OVER THE REGION ON WEDNESDAY IN THE MID LEVELS WHILE LOW LEVELS CONTINUE TO ADVECT WARMTH AND MOISTURE. A FEW WEAK EMBEDDED MID LEVEL SHORTWAVES WILL PROVIDE SOME ASCENT THOUGH THE MAIN ENERGY WILL STREAK ACROSS THE NORTHERN FL PENINSULA. LOW END CHANCE/SCT COVERAGE APPEARS WARRANTED. LOW 80S EXPECTED FOR A HIGH TEMP FOR ALL BUT COASTAL LOCALS WHERE JUST ENOUGH ONSHORE COMPONENT EXPECTED TO TEMPER VALUES...MOST PRONOUNCED ALONG BRUNSWICK CTY. BACKDOOR COLD FRONT ENTERS FROM THE NORTH BY ABOUT 06Z WED NIGHT. THIS SHOULD LEAD TO A BRIEF PUSH OF COOLER AND DRIER AIR WHERE PRECIP MAY TAKE A BREAK LATE WEDNESDAY NIGHT. THIS UNDERCUTTING AIRMASS WILL THEN START BEING OVERRUN BY A RENEWED SENSE OF WARM AND MOIST ADVECTION AS THE SOUTHERN BRANCH CUTOFF OPENS UP AND HEADS EAST. THURSDAY WILL BECOME INCREASINGLY UNSETTLED WITH RAIN CHANCES AND MORESO AMOUNTS HIGHLY HINGING UPON SOME MODEL DISCREPANCIES. THE HIGH GFS AMOUNTS APPEAR ON THE HIGH SIDE AND THE FCST FOLLOWS THE DRIER WRF MORE CLOSELY. HIGH RAIN CHANCES ROUND OUT THE PERIOD AS THE UPPER LOW TRANSFERS ENERGY TO LOW PRESSURE DEVELOPING OFF THE COAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 PM TUESDAY...BEST CHANCE FOR RAIN IN THE PERIOD WILL BE AT THE START OF THE PERIOD AS A SOUTHERN STREAM 5H CUTOFF MOVES ACROSS THE AREA. SURFACE AND UPPER LOW WILL EXIT OFF THE COAST DURING FRI BRINGING AN END TO PRECIP LATE IN THE DAY. WELL BELOW CLIMO TEMPS FRI/FRI NIGHT WITH AREA UNDER THE 5H TROUGH/LOW. TEMPS START TRENDING TO NORMAL SAT AS DEEPER NORTHWEST FLOW DEVELOPS AND THINGS DRY OUT. REMAINDER OF THE PERIOD WILL BE DRY WITH 2 COLD FRONT CROSSING THE AREA LATE IN THE PERIOD. FIRST COLD FRONT PASSES DRY ON MON BUT IS FOLLOWED BY LIMITED COLD ADVECTION AS WINDS QUICKLY BECOME SOUTHERLY AHEAD OF NEXT...MUCH STRONGER COLD FRONT...CROSSING THE AREA TUE. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 00Z...OLD FRONTAL BOUNDARY SOUTH OF THE REGION IS DIFFUSE AND PRETTY MUCH WASHED OUT. THE MOISTURE SOUTH OF THE FRONT WILL WAVE NORTH INTO THE REGION BY TOMORROW MORNING. LOW CONFIDENCE ON SOME IFR STRATUS AT THE SOUTHERN TERMINALS...BUT KEPT IT IN THERE FOR SEVERAL HOURS AFTER 07Z. WEDNESDAY...INCREASING PRECIPITABLE WATER AND CAPES WILL PRODUCED SCATTERED CONVECTION WITH GOOD AFTERNOON HEATING. LOOK FOR THE RESULTANT BOUNDARY TO KICK OFF A FEW...WITH MORE SCATTERED CONVECTION INLAND. WINDS WEDNESDAY WILL BE SOUTHWESTERLY ALL DAY...GUSTY BY MID TO LATE MORNING. EXTENDED OUTLOOK...A GOOD CHANCE OF SHOWERS/EMBEDDED THUNDERSTORMS WITH WIDESPREAD IFR FRIDAY. VFR SATURDAY AND SUNDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM TUESDAY...CONTINUED MINOR ADJUSTMENTS TO WINDS OVERNIGHT...MAINLY CONTINUED DUE TO THE SLOW VEERING OF WIND DIRECTIONS FROM THE S TO SW AS A DIFFUSE WARM FRONT LIFTS ACROSS... AND NORTH OF THE ILM WATERS DURING THE OVERNIGHT. SPEEDS IN GENERAL TO REMAIN 10 TO OCCASIONALLY 15 KT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT THROUGHOUT. A 1 TO 2 FT EASTERLY GROUND SWELL AT 9-11 SECOND PERIODS WILL DOMINATE SIGNIFICANT SEAS...WITH A 1-2 FOOT 3 TO 5 SECOND PERIOD WIND DRIVEN CHOP ADDING A FOOT OR 2 TO THE OVERALL SIG. SEAS. COULD POSSIBLY SEE A FEW 4 FOOTERS ACROSS THE SHALLOW SHOALS OFF CAPE FEAR BUT CONTINUED NOT ENOUGH OF AN OCCURRENCE TO PLACE IN THE CWF. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...PREFRONTAL FLOW REGIME CRANKS UP AS WEDNESDAY PROGRESSES AND THE GRADIENT BECOMES PINCHED BETWEEN WEST ATLANTIC HIGH AND THE APPROACHING BOUNDARY. WEDNESDAY NIGHT THIS MODERATELY STRONG WIND FIELD WILL START VEERING WITH THE APPROACH OF THE BOUNDARY. BEING A BACKDOOR COLD FRONT RATHER THAN A MORE CLASSICAL BOUNDARY COMING IN FROM THE NORTHWEST THIS FRONT WILL MAKE FAIRLY SLOW PROGRESS SOUTHWARD EARLY THURSDAY. THIS MEANS THAT THE NORTHERN AND SOUTHERN ZONES WILL SPEND SEVERAL HOURS SPLIT BETWEEN THE NE AND THE SW WINDS ON EITHER SIDE OF THE BOUNDARY. FURTHER COMPLICATING MATTERS IS THAT THERE IS UNCERTAINTY REGARDING THE TRACK AND STRENGTH OF A LOW EXPECTED TO MOVE WEST TO EAST ACROSS THE REGION. TOUGH TO SAY WHETHER OR NOT SEAS BUILD INTO ADVISORY REALM AT ANY TIME DURING THE PERIOD BUT AN EXTENDED STRETCH OF SCEC HEADLINES APPEARS LIKELY. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 3 PM TUESDAY...STRONG NORTHEAST FLOW OVER THE WATERS FRI/FRI NIGHT WITH GRADIENT PINCHED BETWEEN EXITING SURFACE LOW AND HIGH BUILDING DOWN THE COAST. HEADLINES WILL LIKELY BE REQUIRED FRI FOR ALL WATERS. GRADIENT STARTS TO RELAX SAT BUT HEADLINES WILL LIKELY CARRY OVER INTO THE EVENING BEFORE SEAS DROP BELOW SCA THRESHOLDS. SURFACE RIDGE AXIS REMAINS WEST OF THE WATERS EARLY SUN...WITH NORTHEAST FLOW CONTINUING OVER THE WATERS. HOWEVER...SPEEDS WILL BE MUCH LESS THAN FRI/SAT...10 TO 15 KT INSTEAD OF 20 TO 25 KT. APPROACHING COLD FRONT LATE IN THE PERIOD WILL RESULT IN WINDS BECOMING SOUTHERLY SUN AFTERNOON...THOUGH GRADIENT REMAINS WEAK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...HOEHLER SHORT TERM...BACON LONG TERM...LEBO AVIATION...LOEWENTHAL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
750 PM EDT TUE APR 3 2012 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTH THROUGH THE CAROLINAS WEDNESDAY NIGHT AND EARLY THURSDAY FOLLOWED BY A REINFORCING SHOT OF COLD AIR FRIDAY NIGHT INTO SATURDAY AS STRONG HIGH PRESSURE BUILDS DOWN ACROSS THE CAROLINAS. HIGH PRESSURE WILL WEAKEN AS IT MOVES OFFSHORE ON MONDAY AS YET ANOTHER COLD FRONT APPROACHES FROM THE NORTHWEST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 745 PM...HRRR MODEL OUTPUT INDICATES THE CLUSTER OF CONVECTION ACROSS THE WESTERN PORTIONS OF THE CAROLINAS IS PROGGED TO MAKE SLOW PROGRESS ESE...REACHING THE WESTERN EDGE OF THE ILM CWA AT OR UP TO A FEW HRS AFTER MIDNIGHT. BY THAT TIME...INSTABILITY WILL BE LACKING ESPECIALLY HAVING TRACKED INTO AN ATM ALREADY NONCONDUCIVE FOR TSRA ACTIVITY TO START WITH. WEAK MID LEVEL VORTICIES OVER THE WESTERN CAROLINAS ARE AIDING THE FORCING NEEDED TO SUSTAIN THIS CONVECTION AS IT APPROACHES THE ILM CWA FROM THE WEST DURING THE OVERNIGHT. AS INDICATED B4...HRRR SFC BASED CAPE BASICALLY NON-EXISTENT ACROSS THE ILM CWA BY THE TIME THIS ACTIVITY REACHES THE OUTSKIRTS OF THE ILM CWA. WITH THIS SAID...WILL CONTINUE CURRENT TREND WITH ONLY LOW CHANCE FOR POPS OVERNIGHT...MAINLY ALONG THE WEST THROUGH NORTHWEST OUTLINE OF THE ILM CWA. HAVE LOWERED CLOUD AMOUNTS OVERNIGHT...ESPECIALLY AT THE INITIALIZATION AT 7-8PM...DUE TO LATEST SAT IMAGERY TRENDS AND SFC OBS. NO REASON TO DETOUR CURRENT THINKING FOR THE MIN TEMP FORECAST TONIGHT. ONLY SOME TWEAKING OF SFC DEWPOINTS NEEDED BASED ON LATEST SFC OBS AND LAPS/MSAS ANALYSIS...AND THE LATEST RUN OF THE HRRR AND RUC. PREVIOUS DISCUSSION................................................ AS OF 300 PM TUESDAY...A DIFFUSE WARM FRONT ACROSS EASTERN SOUTH CAROLINA IS NOT REALLY DISCERNIBLE IN WIND OBS ANYMORE...BUT THERE IS STILL A RATHER WELL-DEFINED DEWPOINT GRADIENT. 3 PM DEWPOINTS RANGE FROM THE 40S ACROSS SE NORTH CAROLINA TO 55-60 IN THE SOUTH CAROLINA PEE DEE REGION. THE DIFFUSE FRONT SHOULD MOVE NORTHEAST AND THROUGH OUR AREA LATER THIS EVENING. THIS NEW AIRMASS WILL KEEP US UNSEASONABLY WARM TONIGHT WITH LOWS EXPECTED TO RANGE FROM 60-63...COOLEST IN THE ILM VICINITY. A HEALTHY SUBSIDENCE INVERSION AROUND 800 MB HAS HELD DEEP CONVECTION AT BAY SO FAR TODAY. WIDESPREAD CUMULUS MERGED INTO A STRATOCUMULUS FIELD EARLIER...CAPPED OFF BY THE WARMER MORE STABLE CONDITIONS ALOFT. MODELS SHOW THIS SUBSIDENCE INVERSION WILL ERODE THIS EVENING (SOUTH CAROLINA) OR OVERNIGHT (NORTH CAROLINA) WITH THE APPROACH OF A SERIES OF WEAK UPPER DISTURBANCES...BUT CONDITIONS MAY BECOME TOO DRY ABOVE THE NOCTURNAL INVERSION TO SUPPORT CONVECTION OVERNIGHT. ASIDE FROM THE POTENTIAL OF SOME EVENING SHOWERS SOUTH OF FLORENCE AND ADDITIONAL LATE NIGHT CONVECTION OFFSHORE...WE ARE KEEPING THE FORECAST DRY. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...VERY LOW AMPLITUDE TROUGHINESS/WNW FLOW MOVES OVER THE REGION ON WEDNESDAY IN THE MID LEVELS WHILE LOW LEVELS CONTINUE TO ADVECT WARMTH AND MOISTURE. A FEW WEAK EMBEDDED MID LEVEL SHORTWAVES WILL PROVIDE SOME ASCENT THOUGH THE MAIN ENERGY WILL STREAK ACROSS THE NORTHERN FL PENINSULA. LOW END CHANCE/SCT COVERAGE APPEARS WARRANTED. LOW 80S EXPECTED FOR A HIGH TEMP FOR ALL BUT COASTAL LOCALS WHERE JUST ENOUGH ONSHORE COMPONENT EXPECTED TO TEMPER VALUES...MOST PRONOUNCED ALONG BRUNSWICK CTY. BACKDOOR COLD FRONT ENTERS FROM THE NORTH BY ABOUT 06Z WED NIGHT. THIS SHOULD LEAD TO A BRIEF PUSH OF COOLER AND DRIER AIR WHERE PRECIP MAY TAKE A BREAK LATE WEDNESDAY NIGHT. THIS UNDERCUTTING AIRMASS WILL THEN START BEING OVERRUN BY A RENEWED SENSE OF WARM AND MOIST ADVECTION AS THE SOUTHERN BRANCH CUTOFF OPENS UP AND HEADS EAST. THURSDAY WILL BECOME INCREASINGLY UNSETTLED WITH RAIN CHANCES AND MORESO AMOUNTS HIGHLY HINGING UPON SOME MODEL DISCREPANCIES. THE HIGH GFS AMOUNTS APPEAR ON THE HIGH SIDE AND THE FCST FOLLOWS THE DRIER WRF MORE CLOSELY. HIGH RAIN CHANCES ROUND OUT THE PERIOD AS THE UPPER LOW TRANSFERS ENERGY TO LOW PRESSURE DEVELOPING OFF THE COAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 PM TUESDAY...BEST CHANCE FOR RAIN IN THE PERIOD WILL BE AT THE START OF THE PERIOD AS A SOUTHERN STREAM 5H CUTOFF MOVES ACROSS THE AREA. SURFACE AND UPPER LOW WILL EXIT OFF THE COAST DURING FRI BRINGING AN END TO PRECIP LATE IN THE DAY. WELL BELOW CLIMO TEMPS FRI/FRI NIGHT WITH AREA UNDER THE 5H TROUGH/LOW. TEMPS START TRENDING TO NORMAL SAT AS DEEPER NORTHWEST FLOW DEVELOPS AND THINGS DRY OUT. REMAINDER OF THE PERIOD WILL BE DRY WITH 2 COLD FRONT CROSSING THE AREA LATE IN THE PERIOD. FIRST COLD FRONT PASSES DRY ON MON BUT IS FOLLOWED BY LIMITED COLD ADVECTION AS WINDS QUICKLY BECOME SOUTHERLY AHEAD OF NEXT...MUCH STRONGER COLD FRONT...CROSSING THE AREA TUE. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AS OF 00Z...OLD FRONTAL BOUNDARY SOUTH OF THE REGION IS DIFFUSE AND PRETTY MUCH WASHED OUT. THE MOISTURE SOUTH OF THE FRONT WILL WAVE NORTH INTO THE REGION BY TOMORROW MORNING. LOW CONFIDENCE ON SOME IFR STRATUS AT THE SOUTHERN TERMINALS...BUT KEPT IT IN THERE FOR SEVERAL HOURS AFTER 07Z. WEDNESDAY...INCREASING PRECIPITABLE WATER AND CAPES WILL PRODUCED SCATTERED CONVECTION WITH GOOD AFTERNOON HEATING. LOOK FOR THE RESULTANT BOUNDARY TO KICK OFF A FEW...WITH MORE SCATTERED CONVECTION INLAND. WINDS WEDNESDAY WILL BE SOUTHWESTERLY ALL DAY...GUSTY BY MID TO LATE MORNING. EXTENDED OUTLOOK...A GOOD CHANCE OF SHOWERS/EMBEDDED THUNDERSTORMS WITH WIDESPREAD IFR FRIDAY. VFR SATURDAY AND SUNDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 745 PM TUESDAY...MINOR ADJUSTMENTS TO WINDS OVERNIGHT...MAINLY DUE TO THE SLOW VEERING OF WIND DIRECTIONS FROM THE SE-S TO SW AS THE DIFFUSE WARM FRONT LIFTS ACROSS AND NORTH OF THE ILM WATERS DURING THE OVERNIGHT. SPEEDS IN GENERAL TO REMAIN 10 TO OCCASIONALLY 15 KT. SIG. SEAS WILL RUN 2 TO 3 FT THROUGHOUT. A 1 TO 2 FT EASTERLY GROUND SWELL AT 9-11 SECOND PERIODS WILL DOMINATE SIGNIFICANT SEAS...WITH A 1-2 FOOT 3 TO 5 SECOND PERIOD WIND DRIVEN CHOP ON TOP OF THE EASTERLY SWELL. COMBINING THE 2...YIELDS SIG SEAS IN THE 2 TO 3 FOOT RANGE OVERNIGHT...POSSIBLY A 4 FOOTER ACROSS THE SHOALS BUT NOT ENOUGH OF AN OCCURRENCE TO PLACE IN THE CWF. PREVIOUS DISCUSSION............................................... AS OF 300 PM TUESDAY...HIGH PRESSURE IS NOW WELL OFF THE CAROLINA COAST AS OUR WINDS HAVE SHIFTED TO A SOUTHERLY DIRECTION. THERE IS STILL A NEBULOUS WARM FRONT ACROSS EASTERN SOUTH CAROLINA THAT WILL SLIP ACROSS THE WATERS THIS EVENING. THE ONLY REAL EVIDENCE OF THIS FRONTAL PASSAGE WILL BE A SHIFT TO MORE SOUTHWESTERLY WIND DIRECTIONS. WIND SPEEDS SHOULD PEAK LATE THIS EVENING AROUND 15 KNOTS...OTHERWISE WIND SPEEDS AROUND 10 KNOTS ARE EXPECTED LATE THIS AFTERNOON...AND AGAIN LATE TONIGHT. ISOLATED SHOWERS/T-STORMS WILL BECOME POSSIBLE AFTER MIDNIGHT WITH MODELS SHOWING THE BEST POTENTIAL ACROSS THE NC COASTAL WATERS LATE. DATA FROM THE FRYING PAN SHOALS BUOY SHOWS SEAS CONSIST OF AT LEAST TWO SWELL TRAINS AND A LOCAL WIND WAVE. A NORTHEAST AND A SOUTHEAST SWELL BOTH AVERAGE AROUND 10 SECONDS PERIOD...WITH A MORE CHOPPY 4-5 SECOND WIND CHOP SUPERIMPOSED ON TOP. TOTAL WAVE HEIGHT SHOULD AVERAGE 3 FT IN OPEN WATERS WITHIN 20 MILES OF SHORE...WITH 2 FOOT SEAS WEST OF FRYING PAN SHOALS WHERE MUCH OF THE SWELL ENERGY WILL BE BLOCKED/DISSIPATED ON THE SHOALS. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...PREFRONTAL FLOW REGIME CRANKS UP AS WEDNESDAY PROGRESSES AND THE GRADIENT BECOMES PINCHED BETWEEN WEST ATLANTIC HIGH AND THE APPROACHING BOUNDARY. WEDNESDAY NIGHT THIS MODERATELY STRONG WIND FIELD WILL START VEERING WITH THE APPROACH OF THE BOUNDARY. BEING A BACKDOOR COLD FRONT RATHER THAN A MORE CLASSICAL BOUNDARY COMING IN FROM THE NORTHWEST THIS FRONT WILL MAKE FAIRLY SLOW PROGRESS SOUTHWARD EARLY THURSDAY. THIS MEANS THAT THE NORTHERN AND SOUTHERN ZONES WILL SPEND SEVERAL HOURS SPLIT BETWEEN THE NE AND THE SW WINDS ON EITHER SIDE OF THE BOUNDARY. FURTHER COMPLICATING MATTERS IS THAT THERE IS UNCERTAINTY REGARDING THE TRACK AND STRENGTH OF A LOW EXPECTED TO MOVE WEST TO EAST ACROSS THE REGION. TOUGH TO SAY WHETHER OR NOT SEAS BUILD INTO ADVISORY REALM AT ANY TIME DURING THE PERIOD BUT AN EXTENDED STRETCH OF SCEC HEADLINES APPEARS LIKELY. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 3 PM TUESDAY...STRONG NORTHEAST FLOW OVER THE WATERS FRI/FRI NIGHT WITH GRADIENT PINCHED BETWEEN EXITING SURFACE LOW AND HIGH BUILDING DOWN THE COAST. HEADLINES WILL LIKELY BE REQUIRED FRI FOR ALL WATERS. GRADIENT STARTS TO RELAX SAT BUT HEADLINES WILL LIKELY CARRY OVER INTO THE EVENING BEFORE SEAS DROP BELOW SCA THRESHOLDS. SURFACE RIDGE AXIS REMAINS WEST OF THE WATERS EARLY SUN...WITH NORTHEAST FLOW CONTINUING OVER THE WATERS. HOWEVER...SPEEDS WILL BE MUCH LESS THAN FRI/SAT...10 TO 15 KT INSTEAD OF 20 TO 25 KT. APPROACHING COLD FRONT LATE IN THE PERIOD WILL RESULT IN WINDS BECOMING SOUTHERLY SUN AFTERNOON...THOUGH GRADIENT REMAINS WEAK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH/TRA SHORT TERM...MBB LONG TERM...III AVIATION...LOEWENTHAL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
317 PM EDT MON APR 2 2012 .SYNOPSIS... WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT TONIGHT THROUGH EARLY TUESDAY BEFORE IT MOVES OFFSHORE. UNSETTLED CONDITIONS WILL PERSIST THROUGH MID WEEK AS THIS FRONT RETURNS NORTH AS A WARM FRONT ON TUESDAY. ANOTHER COLD FRONT WILL TRACK SOUTH THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY FOLLOWED BY A REINFORCING SHOT OF COLD AIR FRIDAY NIGHT INTO SATURDAY AS STRONG HIGH PRESSURE BUILDS DOWN ACROSS THE SOUTHEAST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 200 PM MONDAY...COLD FRONT CLEARLY EVIDENT ON VISIBLE IMAGERY THIS AFTN IS CURRENTLY STRETCHED EAST TO WEST FROM WILMINGTON...TO ELIZABETHTOWN...TO ALBEMARLE. THIS HAS NOT BEEN PROGRESSING AS QUICKLY AS GUIDANCE INDICATED...AND THUS TEMPS HAVE SOARED INTO THE LOW 80S MOST LOCATIONS. THE EXCEPTION HAS BEEN ACROSS THE BORDER COUNTIES WHERE A BAND OF PREFRONTAL CLOUDINESS...REMNANTS OF LAST NIGHTS CONVECTION...HAS SIGNIFICANTLY LIMITED HEATING. STILL EXPECT MOST LOCATIONS WILL ECLIPSE 80 THIS AFTN AHEAD OF THE COLD FRONT. CONCERN THOUGH TONIGHT IS CONVECTIVE POTENTIAL ALONG THE BOUNDARY. HAVE SEEN VERY LITTLE IN THE WAY OF CU ON THE SATELLITE THIS AFTN...WHICH IS A BIT SURPRISING. HOWEVER...SPC STILL HAS ALL OF SC OUTLINED FOR POTENTIAL TSTMS ALONG AND AHEAD OF THIS COLD FRONT. LATEST RUC SOUNDINGS DEPICT SLIGHTLY WEAKER CONVECTIVE INDICES THAN EXPECTED THIS MORNING...INCLUDING A SUBTLE DECREASE IN MID LEVEL LAPSE RATES...WHICH MAY BE CONTRIBUTING TO THE LACK OF DIURNAL CU. ADDITIONALLY...VERY DRY AIR ABOVE 500MB IS LIMITING DEEP UPDRAFTS. STILL...WILL KEEP SCHC...ALBEIT WITH LOWER ABSOLUTE POP VALUES...ACROSS SC UNTIL COLD FROPA OCCURS. FEEL THIS IS WARRANTED SINCE SOME AGITATED CU HAS SHOWN UP IMMEDIATELY ALONG THE FRONT...AND LOW LEVEL LAPSE RATES WILL BECOME SUPER-ADIABATIC THROUGH THIS AFTN ACROSS SC ZONES. DO NOT ANTICIPATE TSTMS IN THE NC COUNTIES WHERE FRONTAL INVERSION WILL SQUELCH ANY SURFACE BASED INSTABILITY...BUT A SHOWER OR TWO IS POSSIBLE. SEVERE THREAT IS QUITE LIMITED...BUT AN ISOLATED DAMAGING WIND GUST IS STILL POSSIBLE...ESPECIALLY ACROSS EXTREME SOUTHERN ZONES. FROPA WILL MOVE SOUTH OF THE CWA BY SUNSET...FOLLOWED BY GUSTY N/NE WINDS FOR A FEW HOURS BEFORE GRADIENT SLACKENS AND WINDS EASE. HIGH PRESSURE BUILDS SOUTHWARD AND SKY CONDITIONS WILL CLEAR...SO RADIATIONAL COOLING WILL BE DEPENDENT ON HOW QUICKLY WINDS CAN EASE AFTER SUNSET...TO ALLOW FOR A STEEPER NOCTURNAL INVERSION. HAVE DROPPED MINS ABOUT A DEGREE ACROSS THE NORTHERN ZONES...LEFT STATUS QUO ACROSS SC...WITH UPPER 40S IN NC...TO MID 50S NEAR THE BERKLEY COUNTY LINE. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...BACKDOOR COLD FRONT OFF TO THE SOUTH WILL ALLOW RIDGE OF HIGH PRESSURE TO NOSE INTO THE CAROLINAS FROM THE NORTH EARLY TUESDAY. THIS AIRMASS WILL QUICKLY SLIDE OFF THE COAST BY AFTERNOON. SOME MOISTURE RETURN WILL BE ENSUE FROM WEST TO EAST ACROSS THE CAROLINAS. IN THE UPPER LEVELS A SHORT AMPLITUDE RIDGE WILL HOLD ON FOR THE MOST PART. MODELS STRUGGLING WITH SOME CONVECTIVELY INDUCED VORT CENTERS EMANATING FROM TEXAS...AND DEEPENING ON THE TRACK AND STRENGTH OF THESE FEATURES THEY MAY BE ABLE TO SERVE AS SOME WEAK FORCING LOCALLY. BARRING THIS POSSIBILITY MOST OF THE AREA LOOKS TO REMAIN RAIN-FREE WITH NEAR SEASONABLE TEMPERATURES. ADVECTION OF WARMTH AND MOISTURE WILL CONTINUE FOR THE REMAINDER OF THE PERIOD KEEPING TUESDAY NIGHT VERY MILD ESPECIALLY DUE TO THE INCREASED CLOUD COVER. THE UPPER RIDGE WILL CONTINUE TO BE WEAKENED ON WEDNESDAY ALLOWING CLEARER PASSAGE OF SOME WEAK VORTICITY CENTERS. A PREFRONTAL PIEDMONT TROUGH WILL TEND TO FOCUS MOST OF THE SCATTERED CONVECTION OVER WESTERN ZONES INITIALLY. HOWEVER SINCE STORMS WILL HAVE A WELL DEFINED EASTWARD MOTION THERE WILL BE ONLY A SLIGHT GRADIENT IN FCST POPS AT THIS TIME. QPF WILL BE HIGHER OVER WRN ZONES (ALTHOUGH STILL QUITE LOW). DESPITE THE CLOUD COVER MOST PLACES SHOULD HAVE NO TROUBLE SEEING A HIGH IN THE LOW 80S. COLD FRONT ARRIVES LATE WEDNESDAY NIGHT AND LOOKS QUITE MOISTURE-CHALLENGED. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 3 PM MONDAY...PROGRESSIVE PATTERN WILL PREVAIL THROUGH THE EXTENDED AS A MID LEVEL CYCLONE MOVES ACROSS EARLY FOLLOWED BY BRIEF RIDGING. FINALLY...AT THE END OF THE PERIOD SUBTLE TROUGHING WILL MOVE ACROSS. THE FORECAST CHALLENGES CONTINUE TO CENTER AROUND TIMING AND MAGNITUDE FOR FRIDAY TRANSITIONING TO A TEMPERATURE FORECAST FOR THE WEEKEND. STILL SOME UNCERTAINTY WITH REGARDS TO THE CHARACTERISTIC OF THE SYSTEM FRIDAY AS THE LATEST GFS...AND PAST COUPLE OF CYCLES FOR THAT MATTER SHOW A CLOSED MID LEVEL CYCLONE MOVING ACROSS THE UPSTATE OF SOUTH CAROLINA THEN OPENING UP AND MOVING OFF QUICKLY. THE ECMWF AND ENSEMBLES ARE SIMILAR BUT A BIT FURTHER SOUTH. I HAVE INCREASED POPS TO LIKELY FOR FRIDAY MATCHING HPC AND INCREASED POPS INTO SATURDAY MORNING TO ADDRESS SLOWER TIMING WITH A SYSTEM THAT REMAINS CLOSED FOR A LONGER PERIOD OF TIME. TEMPERATURES DROP TO JUST BELOW CLIMATOLOGY SATURDAY AND SUNDAY BEFORE REBOUNDING QUICKLY WITH A SOUTHWEST FLOW MONDAY. SUNDAY SHOULD BE THE COOLEST MORNING COUPLED WITH THE BEST RADIATIONAL CONDITIONS WITH MID TO UPPER 40S CWA WIDE. SOME CLIMATOLOGICALLY FAVORED AREAS COULD SEE A DEGREE OR TWO BELOW 45. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...THE COLD FRONT CAN CLEARLY BE SEEN IN VISIBLE SATELLITE IMAGERY AND CONTINUITY WAS USED FOR TIMING OF PASSAGE AT THE TERMINALS. SOME PATCHY LIGHT RAIN FROM MAINLY MID-LEVEL CLOUDS IS OCCURRING BUT RADAR LOOPS INDICATES A DECREASING TREND. ANY MID-LEVEL CEILINGS WILL DECREASE THIS AFTERNOON WITH SCATTERED SKIES EXPECTED BY LATE AFTERNOON AT ALL TERMINALS. THERE IS HIGH CONFIDENCE OF VFR AT ALL TERMINALS THROUGH THIS TAF VALID PERIOD. NO THUNDERSTORMS ARE EXPECTED TO AFFECT THE TERMINALS THIS AFTERNOON...ALTHOUGH THERE COULD BE SOME ACTIVITY DEVELOP ALONG THE FRONT SOUTH OF THE FLO/MYR TERMINALS BY LATE AFTERNOON. IF THIS OCCURS THE STORMS SHOULD MOVE WELL SOUTH OF FLO/LBT BY EVENING. THIS EVENING WIND SPEEDS DECREASE AND BECOME NORTHEAST TO EAST AS HIGH PRESSURE SETTLES IN. VFR LEVEL LOW CEILINGS WILL RE-DEVELOP AT THE SOUTHERNMOST TERMINALS OVERNIGHT AND SPREAD TO THE ILM/LBT TERMINALS AFTER SUNRISE. MODELS ARE HINTING THAT LIGHT RAIN COULD RE-DEVELOP AFTER MIDNIGHT...MAINLY WEST AND SOUTH OF FLO. EXTENDED OUTLOOK...VFR TUESDAY. LOW CONFIDENCE ISOLATED SHOWERS AND THUNDERSTORMS WITH TEMPO MVFR WEDNESDAY THROUGH THURSDAY NIGHT. A GOOD CHANCE OF SHOWERS/EMBEDDED THUNDERSTORMS WITH WIDESPREAD IFR FRIDAY. VFR SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 200 PM MONDAY...COLD FRONT CROSSING AMZ250 PRESENTLY...AND THIS WILL CONTINUE ITS TREK SOUTH THROUGH TONIGHT. WINDS AND SEAS HAVE EASED A BIT AT THE LOCAL BUOYS...BUT NOTICED STRONG GUSTY WINDS ACROSS WATERS TO OUR NORTH...AND THUS HAVE EXTENDED THE SCEC THROUGH 6PM FOR THE NORTHERN 2 COASTAL WATER ZONES. EXPECT WINDS TO TURN TO THE N/NE...FIRST ACROSS AMZ250...LASTLY IN AMZ256...AND GUST TO AROUND 25 KTS. THIS WILL HELP REBUILD SEAS TO 3-5 FT...ALTHOUGH THE 5 FTERS WILL BE ISOLATED NEAR THE OUTER 20NM BOUNDARY. WINDS EASE FOR A FEW HOURS AFTER SUNSET AS GRADIENT RELAXES SLIGHTLY IN ADVANCE OF HIGH PRESSURE...BUT A NE SURGE LATE WILL ONCE AGAIN RAISE WINDS TO 15-20 KTS KEEPING SEAS AT 2-4 FT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 PM MONDAY...NORTHEAST WINDS ON TUESDAY WITH A BACKDOOR FRONT OFF TO THE SOUTH AND HIGH PRESSURE BUILDING IN FROM THE NORTH EARLY TUESDAY. THIS HIGH WILL MOVE OFF THE COAST BY AFTERNOON BRINGING VEERING AND PERHAPS DECREASING WINDS. VEERING CONTINUES TUESDAY NIGHT BRINGING A MORE DEFINED SOUTHERLY COMPONENT. NO REAL SWELL ENERGY ON THE RADAR SO SEAS GENERALLY 2 TO 3 FT THROUGHOUT. WEDNESDAY BRINGS A PREFRONTAL SOUTHWESTERLY FLOW REGIME WITH A TIGHTENING GRADIENT. THIS SHOULD ADD ABOUT A FOOT TO THE PREDOMINANT WAVE HEIGHT. LONG TERM /THURSDAY THROUGH SATURDAY/... AS OF 3 PM MONDAY...NORTHEAST FLOW INITIALLY WILL VEER A BIT TO MORE TO AN EASTERLY DIRECTION EARLY FRIDAY AS LOW PRESSURE DROPS WELL TO THE SOUTH. STILL SOME UNCERTAINTY OF THE EXACT TIMING AND PLACEMENT OF THE SYSTEM SO WE COULD SEE WINDS VEER EVEN MORE THROUGH FRIDAY THAN THE CURRENT FORECAST ADVERTISES. NORTHEASTERLY FLOW LATE FRIDAY THROUGH SATURDAY AS HIGH PRESSURE BUILDS IN BEHIND THE SYSTEM. AS USUAL SURGES ARE DIFFICULT TO TIME BUT SHOULD SEE SEVERAL HOURS OF SPEEDS NEAR 20 KNOTS ACROSS THE OUTER WATERS. WAVEWATCH SEAS INCREASE FROM 2-4 FEET EARLY TO 4-7 FEET LATE IN THE PERIOD WITH THE STRONGER FETCH. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...MBB LONG TERM...SHK AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
304 PM EDT MON APR 2 2012 .SYNOPSIS... A BACK DOOR COLD FRONT WILL PUSH SOUTHWEST THROUGH THE AREA THIS AFTERNOON... BEFORE STALLING OVER THE MOUNTAINS... AND NEAR THE SOUTH CAROLINA BORDER TONIGHT. THE FRONT WILL THEN TURN BACK NORTHWARD AS A WARM FRONT TUESDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1039 AM MONDAY... UPDATE: CLEARING ALONG THE I-40 CORRIDOR HAS ALLOWED TEMPS TO REACH THE LOW TO MID 70S IN THAT AREA. CLOUD COVER ACROSS THE SOUTHWEST AND ALONG THE NC/VA BORDER HAVE KEPT TEMPS IN THE MID 60S. AS OF 14Z THE BACKDOOR COLD FRONT WAS STRETCHED FROM DANVILLE VA SOUTH AND EAST ACROSS THE AREA...HANGING OUT JUST EAST OF RDU... SMITHFIELD... AND GOLDSBORO. DEWPOINTS BEHIND THE FRONT ARE CRASHING INTO THE 40S AND LOW 50S...WITH TEMPS IN THE LOW TO MID 60S. SOME LIGHT SHOWERS HAVE STARTED IMPINGE ON THE SOUTHWESTERN EXTENT OF THE AREA. THIS CLOUD COVER AND SHOWERS MAY ACT TO KEEP TEMPS FROM RISING AS HIGH AS PREVIOUSLY THOUGHT...THUS HAVE LOWERED HIGH ACROSS THE SOUTHWEST TO AROUND 81 DEGREES. WITH THE CLEARING ACROSS THE I-40 CORRIDOR AND TEMPS ALREADY IN THE LOW 70S HAVE INCREASED HIGHS SLIGHTLY TO THE MID 70S. PREVIOUS DISCUSSION: OVERVIEW: SURFACE HIGH PRESSURE WILL STRENGTHEN OVER THE OH VALLEY AND MID-ATLANTIC TODAY/TONIGHT AS AN AMPLIFYING UPPER LEVEL TROUGH DIGS SOUTHEAST OFF THE MID-ATLANTIC COAST AND AN UPPER LEVEL RIDGE PROGRESSES FROM THE MS RIVER VALLEY INTO THE APPALACHIANS. PRESSURE RISES UPSTREAM OF THE AREA WILL HELP PUSH A BACK DOOR COLD FRONT (EXTENDING WEST-EAST THROUGH THE OH VALLEY AND NORTHERN VIRGINIAS AT 06Z) SOUTH/SW THROUGH CENTRAL NC TODAY...BEFORE STALLING OUT IN FAR WESTERN NC AND UPSTATE SC TONIGHT. PRECIPITATION CHANCES: UPSTREAM CONVECTION OVER KY/WV/VA AT 06Z APPEARS TO BE DRIVEN BY A COMBINATION OF WEAK LOW-LEVEL CONVERGENCE (IN VICINITY OF) AND WARM ADVECTION (JUST AHEAD OF) THE AFOREMENTIONED FRONTAL ZONE...WITH LITTLE OR NO HELP ALOFT. 06Z SPC MESOANALYSIS INDICATED NO MORE THAN 100-250 J/KG OF MUCAPE OVER CENTRAL NC...WITH THE BEST INSTABILITY (~1000 J/KG MUCAPE) OVER CENTRAL TN/KY IN THE PRESENCE OF MORE FAVORABLE BOUNDARY LAYER MOISTURE (SFC DEWPOINTS UPPER 50S) AND STEEPER MID-LEVEL LAPSE RATES (7-8 C/KM). AS A RESULT...EXPECT CONVECTION UPSTREAM OF THE AREA TO GENERALLY WEAKEN THROUGH 09Z AS SPEEDY NORTHWEST FLOW ALOFT PUSHES ACTIVITY AWAY FROM THE BEST LOW-LEVEL FORCING AND INTO A GENERALLY UNFAVORABLE THERMODYNAMIC ENVIRONMENT OVER THE NC PIEDMONT. HOWEVER...A RESPECTABLE (25 KFT ECHO TOPS) CONVECTIVE CELL THAT DEVELOPED JUST SOUTH OF DANVILLE ~07Z SUGGESTS THAT SUBTLE UPPER LEVEL FORCING IS PRESENT...AND/OR THAT DEEP-LAYER SHEAR (40-50 KT) SUPPORTIVE OF UPDRAFT ROTATION MAY BE ENHANCING UPDRAFTS. AS THE BACK DOOR COLD FRONT APPROACHES THE AREA FROM THE N/NE THROUGH 12Z...LOW-LEVEL MOISTURE WILL BEGIN TO INCREASE...AND SOME MARGINAL DESTABILIZATION IS EXPECTED. DESTABILIZATION WILL BE MOST PROMINENT IN THE FAR SOUTHWEST PIEDMONT (PERHAPS 500-750 J/KG MLCAPE) WHERE DIURNAL HEATING IS MOST LIKELY TO BE A CONTRIBUTING FACTOR IN ADVANCE OF THE AFOREMENTIONED FROPA. THE LATEST WRF-NMM SIMULATED REFLECTIVITY PRODUCT INDICATES A BROKEN LINE OF CONVECTION DEVELOPING NEAR OR JUST SOUTH OF THE VA BORDER AND PROGRESSING SOUTH/SW THROUGH CENTRAL NC IN ADVANCE OF THE BACK DOOR FRONT BETWEEN ROUGHLY 09-12Z. WITH THE ABOVE IN MIND... WILL INDICATE ISOLD TO SCT SHOWERS/STORMS ACROSS THE AREA THROUGH ~15Z...WITH THE BEST CHANCE IN THE NORTHERN PIEDMONT EARLY THIS MORNING...TRANSITIONING TO THE WEST/SW PIEDMONT BY MID MORNING. AFTER ~15Z...A COOL/STABLE AIRMASS ADVECTING INTO THE AREA FROM THE NORTHEAST IN THE WAKE OF THE FRONT WILL EFFECTIVELY END PRECIP CHANCES. HOWEVER...DEPENDING ON THE SPEED/PROGRESS OF THE BACK DOOR FRONT...ISOLD CONVECTION MAY REMAIN POSSIBLE INTO THE AFTERNOON IN THE FAR WEST/SW PIEDMONT AT THE EASTERN FRINGE OF THE INSTABILITY GRADIENT. EXPECT PRECIP CHANCES NEAR ~0 EVEN IN THE WEST/SW PIEDMONT BY 00Z THIS EVENING THROUGH SUNRISE TUE MORNING. TEMPERATURES: CHALLENGING TEMPERATURE FCST WITH A POTENTIAL TO BUST HIGHS BY 5-10F. HIGHS TODAY WILL DEPEND ENTIRELY ON THE TIMING OF THE BACKDOOR COLD FRONTAL PASSAGE. THE LATEST 00Z GUIDANCE INDICATES HIGHS RANGING FROM THE LOWER/MID 60S IN NORTHEAST NC (I.E. ELIZABETH CITY/AHOSKIE) TO THE LOWER/MID 80S IN WEST/SOUTHWEST NC. WILL INDICATE HIGHS RANGING FROM THE UPPER 60S/NEAR 70F IN THE FAR NORTHEAST COASTAL PLAIN TO THE LOWER/MID 80S IN THE FAR SW PIEDMONT. LOWS TONIGHT WILL BE EQUALLY CHALLENGING GIVEN THAT THE FRONT IS EXPECTED TO STALL JUST WEST OF CENTRAL NC. EXPECT LOWS TO RANGE FROM THE UPPER 30S/LOWER 40S IN THE E/NE COASTAL PLAIN TO THE LOWER 50S IN THE WEST/SW PIEDMONT. SEVERE THREAT: 0-6KM BULK SHEAR VALUES IN THE 40-50 KT RANGE ARE SUPPORTIVE OF SUPERCELLS...THOUGH SEVERE WEATHER APPEARS UNLIKELY THROUGH SUNRISE GIVEN BAD DIURNAL TIMING AND LITTLE IN THE WAY OF INSTABILITY. IN FACT...STRONG NW FLOW ALOFT WILL LIKELY SHEAR APART ANY CONVECTION THAT DEVELOPS PRIOR TO SUNRISE. HOWEVER...AN ISOLD SEVERE THREAT (HAIL/WIND) WILL BE POSSIBLE IN THE SW PIEDMONT BETWEEN 12-18Z WHERE INCREASING BOUNDARY LAYER MOISTURE AND DIURNAL HEATING IN ADVANCE OF THE BACK DOOR FRONT WILL ALLOW MARGINAL DESTABILIZATION TO OCCUR IN THE PRESENCE OF 0-6KM BULK SHEAR VALUES SUPPORTIVE OF SUPERCELLS. ALTHOUGH 07Z SPC MESOANALYSIS INDICATED 300-400 M2/S2 OF 0-1 KM SRH OVER CENTRAL NC...THE LATEST RUC GUIDANCE SHOWS 0-1KM SRH RAPIDLY DIMINISHING TO LESS THAN 100 M2/S2 AFTER SUNRISE. THE RELATIVE BEST CHANCE OF SEVERE WEATHER IS EXPECTED TO REMAIN SOUTH AND WEST OF THE AREA IN SC AND SOUTHWEST NC TODAY...WHERE A MORE DIURNALLY FAVORABLE FROPA WILL OCCUR. -VINCENT && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... AS OF 235 PM MONDAY... A WARM ADVECTION PATTERN WILL BE UNDERWAY ACROSS CENTRAL NORTH CAROLINA TUESDAY EVENING AS THE WARM FRONT WILL BE NORTH OF THE REGION. THE LATEST MODELS GENERALLY AGREE IN THAT THE CHANCE OF SHOWERS/ISOLATED THUNDERSTORMS WILL BE OF A DIURNAL NATURE IN THE WARM SECTOR LATE TUESDAY/TUESDAY EVENING... SHOULD BE CONFINED TO THE MOUNTAINS INTO THE EVENING HOURS BEFORE WEAKENING. THE CURRENT THINKING IS THAT THERE MAY BE AN ISOLATED SHOWER OR THUNDERSTORM MAINLY OVER THE WESTERN PIEDMONT BUT CENTRAL NORTH CAROLINA SHOULD REMAIN LARGELY DRY TUESDAY NIGHT. SINCE WE WILL IN THE WARM SECTOR... A SW BREEZE AROUND 10 MPH WILL KEEP TEMPERATURES UP TUESDAY NIGHT WITH LOWS EXPECTED TO BE MOSTLY IN THE UPPER 50S TO LOWER 60S. WEDNESDAY AND WEDNESDAY NIGHT... INCREASING INSTABILITY ALONG WITH STRONG SURFACE HEATING AND AN APPROACHING UPPER LEVEL DISTURBANCE IN THE NW FLOW ALOFT WILL INCREASE THE CHANCE OF THUNDERSTORMS WEDNESDAY AFTERNOON. THE BEST CHANCE OF THUNDERSTORMS SHOULD BE ALONG OR NEAR 1)A PIEDMONT TROUGH THAT IS FORECAST TO ALIGN FROM SW TO NE ACROSS OUR REGION... AND 2) THE ASSOCIATED SURFACE BOUNDARY THAT IS FORECAST TO DIP SOUTH INTO THE REGION DURING THE LATE AFTERNOON INTO THE EVENING. PARTLY SUNNY SKIES SHOULD LEAD TO EXCELLENT HEATING AS HIGHS REACH THE 80-85 RANGE... WITH SOME UPPER 80S POSSIBLE IN THE SANDHILLS. INCREASING WINDS IN THE MID AND UPPER LEVELS SHOULD HELP WITH STORM ORGANIZATION. MLCAPES OF NEAR 1500+ J/KG ARE EXPECTED TO LEAD TO AT LEAST SCATTERED THUNDERSTORMS BY EARLY AFTERNOON ALONG THE PIEDMONT TROUGH... WITH ADDITIONAL CONVECTION EXPECTED TO FIRE ALONG THE SOUTHWARD MOVING COLD FRONT LATER IN THE AFTERNOON NEAR THE NC/VA BORDER. THE LATTER MAY EVENTUALLY EVOLVE INTO A LINE OF SHOWERS AND THUNDERSTORMS. A FEW OF THE STORMS MAY BECOME SEVERE WITH THE MAIN THREATS BEING STRONG WIND GUSTS TO NEAR SEVERE LIMITS AND POSSIBLY MARGINALLY SEVERE HAIL (UP TO THE SIZE OF QUARTERS). THE THREAT OF STRONG STORMS SHOULD PERSIST WELL INTO THE EVENING AND POSSIBLY OVERNIGHT (IN THE SOUTHERN ZONES). OTHERWISE... HIGHS ARE EXPECTED TO REACH 80-85 WITH POTENTIALLY SOME UPPER 80S OVER THE SANDHILLS. WEAK HIGH PRESSURE IS EXPECTED TO PUSH SOUTHWARD FROM THE MID-ATLANTIC STATES INTO NE SECTIONS OF THE AREA WEDNESDAY NIGHT... OTHERWISE A WEAK BOUNDARY WILL STALL OVER WESTERN AND SOUTHERN ZONES. UNDER VARIABLY CLOUDY SKIES... THERE WILL STILL BE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MAINLY IN THE SOUTH AND SOUTHWEST PIEDMONT OVERNIGHT. LOWS WILL BE COOLEST NE AND WARMEST SW (LOWER 50S TO LOWER 60S). && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 304 PM MONDAY... THE LATEST MODELS CONTINUE TO ADVERTISE THAT AN APPROACHING MID-UPPER LEVEL LOW FROM THE SOUTHERN PLAINS STATES WILL GRADUALLY WEAKEN AND DIP MORE SOUTHERLY ACROSS THE TENNESSEE VALLEY AND OVER GA/SC THURSDAY THROUGH FRIDAY. THE COMBINATION OF A WEAK SURFACE HIGH NEAR THE NC/VA COAST COMBINED WITH A WARM FRONT WELL TO OUR SOUTH SHOULD LEAD TO A MOSTLY CLOUDY DAY THURSDAY. A MOIST EASTERLY LOW LEVEL FLOW WILL BRING INCREASING ATLANTIC MOISTURE ACROSS OUR REGION. THIS COMBINED WITH THE APPROACHING UPPER LEVEL LOW WILL CREATE AT LEAST A CHANCE OF SHOWERS (MAINLY WEST) THURSDAY. AS THE MID-UPPER LOW DAMPENS AND SLIDES MORE SE... THE BEST CHANCE OF RAIN WILL LIKELY BE OVER WESTERN AND SOUTHERN NC... WITH THE LEAST CHANCE ACROSS THE NE ZONES. HOWEVER... UNCERTAINTY STILL ABOUNDS WITH THE STRENGTH AND TRACK OF THIS UPPER SYSTEM. IF THE CURRENT MODELS ARE CORRECT... THEN MUCH OF THE HEAVY RAIN SHOULD BE CONFINED JUST TO OUR SW AS OUR SYSTEM DIVES SE. IF THE SYSTEM REMAINS STRONGER THAN CURRENTLY FORECAST... THEN IT IS ENTIRELY POSSIBLE THAT IT WOULD CONTINUE MOVING EAST AND BRING THE HEAVIER RAIN NORTHEASTWARD OVER CENTRAL NC. AT THE VERY LEAST... THIS LOOKS TO BE A COOL/CLOUDY PERIOD (THU-FRI)... WITH QPF OF 0.25 TO 0.50 SW... LESSER AMOUNTS AROUND 0.10 NE. LOWS 50-60 NE TO SW. HIGHS NEAR 60 NORTH TO LOWER 70S SOUTH EXPECTED THURSDAY... POSSIBLY COOLER FRIDAY DEPENDING ON THE TRACK OF THE SYSTEM AND AMOUNT OF RAIN. SATURDAY THROUGH MONDAY... MUCH COOLER AND DRIER AIR IS FORECAST BASED ON THE GENERAL MODEL CONSENSUS OF 1025+ MB SURFACE HIGH PRESSURE BUILDING SOUTH INTO NC/SC FROM NEW ENGLAND. ANOTHER COLD FRONT WILL BRING ADDITIONAL COOLING MONDAY NIGHT AND TUESDAY. LOWS SAT-SUN SHOULD AVERAGE IN THE UPPER 30S TO MID 40S WITH SOME MID 30S POSSIBLE IN THE NE. HIGHS GENERALLY IN THE MID 60S TO LOWER 70S SAT-SUN... AND 70S MONDAY. && .AVIATION /18Z MONDAY THROUGH FRIDAY/... AS OF 145 PM MONDAY... 24-HR TAF PERIOD: VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. AHEAD OF THE BACKDOOR COLD FRONT WINDS WILL BE NNW AT 5-10 KT...WITH WINDS BEHIND THE FRONT NNE AT 10-15 KT GUSTING UP TO 20 KT. EXPECT GUSTS TO DIE DOWN AROUND SUNSET...WITH MAINLY EASTERLY WINDS AT 5 KTS OR LESS ACROSS ALL TERMINALS THROUGH SUNRISE. SKIES WILL BE MAINLY CLEAR OVERNIGHT WITH THE EXCEPTION OF SOME SCATTERED CLOUDS AT KINT AND KGSO. SHOULD SEE SOME BROKEN CIGS AROUND 3500 FT MOVING INTO THE AREA FROM WEST TO EAST...STARTING AROUND 08Z AT KINT AND KGSO AND MAKING IT TOWARD KRWI AT THE END OF THE TAF PERIOD. LOOKING AHEAD: MVFR CEILINGS ARE PROGGED TO DEVELOP EARLY TUE MORNING (06-12Z) IN VICINITY OF THE STALLED FRONT OVER UPSTATE SC AND SOUTHWEST NC. MVFR CEILINGS MAY MAKE THEIR WAY INTO THE AREA FROM SW-NE OR W-E AS THE STALLED FRONT LIFTS BACK THROUGH CENTRAL NC AS A WARM FRONT DURING THE DAY TUE. A PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE EARLY WED MORNING (06-12Z) IN ASSOC/W WARM ADVECTION UNDER THE NOCTURNAL INVERSION. ISOLD TO SCT SHOWERS AND STORMS ARE EXPECTED DURING THE DAY WED IN ADVANCE OF ANOTHER BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTH. A PROLONGED PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE THU THROUGH FRI IN ASSOC/W LOW-LEVEL NORTHEAST FLOW IN THE WAKE OF THE AFOREMENTIONED COLD FRONT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BADGETT NEAR TERM...KC/VINCENT SHORT TERM...BADGETT LONG TERM...BADGETT AVIATION...KC/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
207 PM EDT MON APR 2 2012 .SYNOPSIS... A COLD FRONT WILL DROP SOUTH ACROSS THE AREA TODAY AND MAY RESULT IN SOME STRONG STORMS ACROSS PORTIONS OF THE AREA THIS AFTERNOON. WEAK HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT TONIGHT THROUGH EARLY TUESDAY BEFORE IT MOVES OFFSHORE. UNSETTLED CONDITIONS WILL PERSIST THROUGH MID WEEK AS THIS FRONT RETURNS NORTH AS A WARM FRONT ON TUESDAY. ANOTHER COLD FRONT WILL TRACK SOUTH THROUGH THE AREA WEDNESDAY NIGHT INTO THURSDAY FOLLOWED BY A REINFORCING SHOT OF COLD AIR FRIDAY NIGHT INTO SATURDAY AS STRONG HIGH PRESSURE BUILDS DOWN ACROSS THE SOUTHEAST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 200 PM MONDAY...COLD FRONT CLEARLY EVIDENT ON VISIBLE IMAGERY THIS AFTN IS CURRENTLY STRETCHED EAST TO WEST FROM WILMINGTON...TO ELIZABETHTOWN...TO ALBERMARLE. THIS HAS NOT BEEN PROGRESSING AS QUICKLY AS GUIDANCE INDICATED...AND THUS TEMPS HAVE SOARED INTO THE LOW 80S MOST LOCATIONS. THE EXCEPTION HAS BEEN ACROSS THE BORDER COUNTIES WHERE A BAND OF PREFRONTAL CLOUDINESS...REMNANTS OF LAST NIGHTS CONVECTION...HAS SIGNIFICANTLY LIMITED HEATING. STILL EXPECT MOST LOCATIONS WILL ECLIPSE 80 THIS AFTN AHEAD OF THE COLD FRONT. CONCERN THOUGH TONIGHT IS CONVECTIVE POTENTIAL ALONG THE BOUNDARY. HAVE SEEN VERY LITTLE IN THE WAY OF CU ON THE SATELLITE THIS AFTN...WHICH IS A BIT SURPRISING. HOWEVER...SPC STILL HAS ALL OF SC OUTLINED FOR POTENTIAL TSTMS ALONG AND AHEAD OF THIS COLD FRONT. LATEST RUC SOUNDINGS DEPICT SLIGHTLY WEAKER CONVECTIVE INDICES THAN EXPECTED THIS MORNING...INCLUDING A SUBTLE DECREASE IN MID LEVEL LAPSE RATES...WHICH MAY BE CONTRIBUTING TO THE LACK OF DIURNAL CU. ADDITIONALLY...VERY DRY AIR ABOVE 500MB IS LIMITING DEEP UPDRAFTS. STILL...WILL KEEP SCHC...ALBEIT WITH LOWER ABSOLUTE POP VALUES...ACROSS SC UNTIL COLD FROPA OCCURS. FEEL THIS IS WARRANTED SINCE SOME AGITATED CU HAS SHOWN UP IMMEDIATELY ALONG THE FRONT...AND LOW LEVEL LAPSE RATES WILL BECOME SUPER-ADIABATIC THROUGH THIS AFTN ACROSS SC ZONES. DO NOT ANTICIPATE TSTMS IN THE NC COUNTIES WHERE FRONTAL INVERSION WILL SQUELCH ANY SURFACE BASED INSTABILITY...BUT A SHOWER OR TWO IS POSSIBLE. SEVERE THREAT IS QUITE LIMITED...BUT AN ISOLATED DAMAGING WIND GUST IS STILL POSSIBLE...ESPECIALLY ACROSS EXTREME SOUTHERN ZONES. FROPA WILL MOVE SOUTH OF THE CWA BY SUNSET...FOLLOWED BY GUSTY N/NE WINDS FOR A FEW HOURS BEFORE GRADIENT SLACKENS AND WINDS EASE. HIGH PRESSURE BUILDS SOUTHWARD AND SKY CONDITIONS WILL CLEAR...SO RADIATIONAL COOLING WILL BE DEPENDENT ON HOW QUICKLY WINDS CAN EASE AFTER SUNSET...TO ALLOW FOR A STEEPER NOCTURNAL INVERSION. HAVE DROPPED MINS ABOUT A DEGREE ACROSS THE NORTHERN ZONES...LEFT STATUS QUO ACROSS SC...WITH UPPER 40S IN NC...TO MID 50S NEAR THE BERKELY COUNTY LINE. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...WITH SURFACE FRONT JUST SOUTH A COOLER NORTHEASTERLY FLOW WILL KEEP TEMPS AROUND CLIMO. WEAK HIGH PRESSURE SHIFTING OFF SHORE WILL ALLOW A RETURN FLOW TO SET UP AT THE SFC BY LATER ON TUES...WITH DRIER AIR STILL PRESENT ALOFT. THIS WILL ALLOW OLD BOUNDARY TO THE SOUTH TO GET PUSHED BACK NORTH AS A WARM FRONT WITH WEAK LIFT GIVING POSSIBILITY OF PCP MAINLY OVER SC ZONES BY LATE TUES. BY TUES NIGHT A SHORTWAVE WILL TRACK AROUND THE MID TO UPPER RIDGE ACROSS LOCAL AREA. THIS HELPS TO FLATTEN OUT THE RIDGE OVER THE SOUTHEAST. EXPECT INCREASING CLOUDS AND CHC OF PCP AS THIS IMPULSE RIDES THROUGH TUES NIGHT. THIS WILL HELP TO KEEP TEMPS UP TUES NIGHT. PCP WATER INCREASES UP TO 1.5 INCHES OVERNIGHT TUES INTO WED. ANOTHER SURFACE COLD FRONT WILL TRACK SOUTH ON WED AND WILL REACH AREA BY WED EVENING AS MOISTURE IN THE MID TO UPPER LEVELS INCREASES FROM THE WEST AHEAD OF ANOTHER SYSTEM TRACKING EAST ACROSS THE TENNESSEE VALLEY. WILL REMAIN IN WARM SECTOR IN A WARMER AND MORE UNSTABLE ATMOSPHERE AHEAD OF COLD FRONT TRACKING APPROACHING THE CAROLINAS BY AFTN. OVERALL EXPECT A FAIR AMOUNT OF CLOUDS A CHC OF SHWRS/TSTMS ON WED. TEMPS SHOULD WARM TO AROUND 80 TO 85 WED IN A WARMER AND MOISTER SOUTHWEST TO WESTERLY FLOW AHEAD OF NEXT COLD FRONT. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...BACK DOOR COLD FRONT WILL TRACK THROUGH AREA ON THURS. THIS SHALLOW COOLER AIR WILL ADVECT IN WITH NE TO E FLOW AND WEST SOUTHWEST FLOW ABOVE IT. GFS SHOWING BEST LIFT EARLY THURS AND PCP WATER VALUES UP AROUND 1.5 INCHES. EXPECT UNSETTLED WEATHER WITH CLOUDS AND CHC OF PCP THROUGH THURS INTO FRI BEFORE MID TO UPPER TROUGH PUSHES A COLD FRONT THROUGH BY SAT. THIS WILL SCOUR OUT ANY MOISTURE LEFT AND COOLER AND DRIER HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND IN A DEEPER NORTHERLY FLOW SAT THROUGH SUNDAY. LATEST GFS NOT AS AGGRESSIVE WITH COLD AIR BUT DOES BRING 850 TEMPS DOWN FROM 14 C MID WEEK TO 5 C ON SATURDAY. H5 HEIGHTS BOTTOM OUT AS MID TO UPPER TROUGH AXIS MOVES THROUGH AREA LATE FRI AND THEN RIDGE BUILDS UP THE EAST COAST WITH HEIGHTS REACHING UP AROUND 580 DEM BY SUNDAY. PCP WATER VALUES FALL TO LESS THAN A HALF INCH BY SAT AFTN AND DECREASE FURTHER THROUGH THE REMAINDER OF THE WEEKEND IN DEEP NORTHEASTERLY FLOW. TEMPS WILL REMAIN AT OR BELOW CLIMO THROUGH THE LONG TERM PERIOD. INITIALLY ON THURS AND FRI...A SHALLOW COOL POOL WITH CLOUDS AND PCP WILL HOLD TEMPS DOWN CLOSER TO 70 AND THEN COOL AND DRY AIR WILL ADVECT IN BEHIND FRONT FOR THE WEEKEND. THIS WILL KEEP TEMPS AROUND 70 THROUGH THE WEEKEND. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...THE COLD FRONT CAN CLEARLY BE SEEN IN VISIBLE SATELLITE IMAGERY AND CONTINUITY WAS USED FOR TIMING OF PASSAGE AT THE TERMINALS. SOME PATCHY LIGHT RAIN FROM MAINLY MID-LEVEL CLOUDS IS OCCURRING BUT RADAR LOOPS INDICATES A DECREASING TREND. ANY MID-LEVEL CEILINGS WILL DECREASE THIS AFTERNOON WITH SCATTERED SKIES EXPECTED BY LATE AFTERNOON AT ALL TERMINALS. THERE IS HIGH CONFIDENCE OF VFR AT ALL TERMINALS THROUGH THIS TAF VALID PERIOD. NO THUNDERSTORMS ARE EXPECTED TO AFFECT THE TERMINALS THIS AFTERNOON...ALTHOUGH THERE COULD BE SOME ACTIVITY DEVELOP ALONG THE FRONT SOUTH OF THE FLO/MYR TERMINALS BY LATE AFTERNOON. IF THIS OCCURS THE STORMS SHOULD MOVE WELL SOUTH OF FLO/LBT BY EVENING. THIS EVENING WIND SPEEDS DECREASE AND BECOME NORTHEAST TO EAST AS HIGH PRESSURE SETTLES IN. VFR LEVEL LOW CEILINGS WILL RE-DEVELOP AT THE SOUTHERNMOST TERMINALS OVERNIGHT AND SPREAD TO THE ILM/LBT TERMINALS AFTER SUNRISE. MODELS ARE HINTING THAT LIGHT RAIN COULD RE-DEVELOP AFTER MIDNIGHT...MAINLY WEST AND SOUTH OF FLO. EXTENDED OUTLOOK...VFR TUESDAY. LOW CONFIDENCE ISOLATED SHOWERS AND THUNDERSTORMS WITH TEMPO MVFR WEDNESDAY THROUGH THURSDAY NIGHT. A GOOD CHANCE OF SHOWERS/EMBEDDED THUNDERSTORMS WITH WIDESPREAD IFR FRIDAY. VFR SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 200 PM MONDAY...COLD FRONT CROSSING AMZ250 PRESENTLY...AND THIS WILL CONTINUE ITS TREK SOUTH THROUGH TONIGHT. WINDS AND SEAS HAVE EASED A BIT AT THE LOCAL BUOYS...BUT NOTICED STRONG GUSTY WINDS ACROSS WATERS TO OUR NORTH...AND THUS HAVE EXTENDED THE SCEC THROUGH 6PM FOR THE NORTHERN 2 COASTAL WATER ZONES. EXPECT WINDS TO TURN TO THE N/NE...FIRST ACROSS AMZ250...LASTLY IN AMZ256...AND GUST TO AROUND 25 KTS. THIS WILL HELP REBUILD SEAS TO 3-5 FT...ALTHOUGH THE 5 FTERS WILL BE ISOLATED NEAR THE OUTER 20NM BOUNDAY. WINDS EASE FOR A FEW HOURS AFTER SUNSET AS GRADIENT RELAXES SLIGHTLY IN ADVANCE OF HIGH PRESSURE...BUT A NE SURGE LATE WILL ONCE AGAIN RAISE WINDS TO 15-20 KTS KEEPING SEAS AT 2-4 FT. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...LINGERING SURFACE COLD FRONT SHOULD BE JUST SOUTH OF LOCAL WATERS TUES MORNING WITH A LIGHT NE TO E FLOW. WEAK HIGH PRESSURE BEHIND FRONT WILL SHIFT OFF SHORE AS WINDS CONTINUE TO VEER AROUND TO THE E-SE BEFORE RETURN FLOW SETS UP THROUGH LATE TUES WITH WINDS INCREASING OUT OF THE S-SW THROUGH EARLY WED. WINDS WILL CONTINUE TO VEER ON WED TO THE SW TO W AHEAD OF COLD FRONT APPROACHING THE CAROLINAS FROM THE NW. SEAS WILL MAINLY BE 2 TO 3 FT DECREASING SLIGHTLY INITIALLY ON TUES IN WEAKENING FLOW AND THEN INCREASING IN INCREASING W-SW FLOW ON WED. THE OFF SHORE COMPONENT TO THE FLOW WILL MAINLY AFFECT THE OUTER WATERS WITH AN INCREASE IN SEAS UP TO 3 TO 4 FT WED INTO WED NIGHT. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...COLD FRONT WILL MAKE ITS WAY SOUTH ON THURS WITH WINDS VEERING AROUND FROM THE W-NW TO N-NE THROUGH THE DAY. WINDS WILL CONTINUE OUT OF THE NE THROUGH FRI AND WILL THEN INCREASE UP TO 15 TO 25 KTS BY LATE FRI INTO SAT AS SURGE TAKES PLACE BEHIND FRONT. THESE INCREASING NE WINDS FRI NIGHT WILL TIP SEAS INTO SCA THRESHOLDS BY FRI EVENING AND COULD REACH AS HIGH AS 7 TO 8 FT IN OUTER WATERS IN FLOW REMAINING MAINLY PARALLEL TO THE COAST BY SAT MORNING. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...JDW SHORT TERM...RGZ LONG TERM...RGZ AVIATION...MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
149 PM EDT MON APR 2 2012 .SYNOPSIS... A BACK DOOR COLD FRONT WILL PUSH SOUTHWEST THROUGH THE AREA TODAY BEFORE STALLING OUT OVER THE WESTERN CAROLINAS TONIGHT. THE STALLED BOUNDARY WILL LIFT NORTHEAST THROUGH CENTRAL NORTH CAROLINA AS A WARM FRONT DURING THE DAY TUESDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1039 AM MONDAY... UPDATE: CLEARING ALONG THE I-40 CORRIDOR HAS ALLOWED TEMPS TO REACH THE LOW TO MID 70S IN THAT AREA. CLOUD COVER ACROSS THE SOUTHWEST AND ALONG THE NC/VA BORDER HAVE KEPT TEMPS IN THE MID 60S. AS OF 14Z THE BACKDOOR COLD FRONT WAS STRETCHED FROM DANVILLE VA SOUTH AND EAST ACROSS THE AREA...HANGING OUT JUST EAST OF RDU... SMITHFIELD... AND GOLDSBORO. DEWPOINTS BEHIND THE FRONT ARE CRASHING INTO THE 40S AND LOW 50S...WITH TEMPS IN THE LOW TO MID 60S. SOME LIGHT SHOWERS HAVE STARTED IMPINGE ON THE SOUTHWESTERN EXTENT OF THE AREA. THIS CLOUD COVER AND SHOWERS MAY ACT TO KEEP TEMPS FROM RISING AS HIGH AS PREVIOUSLY THOUGHT...THUS HAVE LOWERED HIGH ACROSS THE SOUTHWEST TO AROUND 81 DEGREES. WITH THE CLEARING ACROSS THE I-40 CORRIDOR AND TEMPS ALREADY IN THE LOW 70S HAVE INCREASED HIGHS SLIGHTLY TO THE MID 70S. PREVIOUS DISCUSSION: OVERVIEW: SURFACE HIGH PRESSURE WILL STRENGTHEN OVER THE OH VALLEY AND MID-ATLANTIC TODAY/TONIGHT AS AN AMPLIFYING UPPER LEVEL TROUGH DIGS SOUTHEAST OFF THE MID-ATLANTIC COAST AND AN UPPER LEVEL RIDGE PROGRESSES FROM THE MS RIVER VALLEY INTO THE APPALACHIANS. PRESSURE RISES UPSTREAM OF THE AREA WILL HELP PUSH A BACK DOOR COLD FRONT (EXTENDING WEST-EAST THROUGH THE OH VALLEY AND NORTHERN VIRGINIAS AT 06Z) SOUTH/SW THROUGH CENTRAL NC TODAY...BEFORE STALLING OUT IN FAR WESTERN NC AND UPSTATE SC TONIGHT. PRECIPITATION CHANCES: UPSTREAM CONVECTION OVER KY/WV/VA AT 06Z APPEARS TO BE DRIVEN BY A COMBINATION OF WEAK LOW-LEVEL CONVERGENCE (IN VICINITY OF) AND WARM ADVECTION (JUST AHEAD OF) THE AFOREMENTIONED FRONTAL ZONE...WITH LITTLE OR NO HELP ALOFT. 06Z SPC MESOANALYSIS INDICATED NO MORE THAN 100-250 J/KG OF MUCAPE OVER CENTRAL NC...WITH THE BEST INSTABILITY (~1000 J/KG MUCAPE) OVER CENTRAL TN/KY IN THE PRESENCE OF MORE FAVORABLE BOUNDARY LAYER MOISTURE (SFC DEWPOINTS UPPER 50S) AND STEEPER MID-LEVEL LAPSE RATES (7-8 C/KM). AS A RESULT...EXPECT CONVECTION UPSTREAM OF THE AREA TO GENERALLY WEAKEN THROUGH 09Z AS SPEEDY NORTHWEST FLOW ALOFT PUSHES ACTIVITY AWAY FROM THE BEST LOW-LEVEL FORCING AND INTO A GENERALLY UNFAVORABLE THERMODYNAMIC ENVIRONMENT OVER THE NC PIEDMONT. HOWEVER...A RESPECTABLE (25 KFT ECHO TOPS) CONVECTIVE CELL THAT DEVELOPED JUST SOUTH OF DANVILLE ~07Z SUGGESTS THAT SUBTLE UPPER LEVEL FORCING IS PRESENT...AND/OR THAT DEEP-LAYER SHEAR (40-50 KT) SUPPORTIVE OF UPDRAFT ROTATION MAY BE ENHANCING UPDRAFTS. AS THE BACK DOOR COLD FRONT APPROACHES THE AREA FROM THE N/NE THROUGH 12Z...LOW-LEVEL MOISTURE WILL BEGIN TO INCREASE...AND SOME MARGINAL DESTABILIZATION IS EXPECTED. DESTABILIZATION WILL BE MOST PROMINENT IN THE FAR SOUTHWEST PIEDMONT (PERHAPS 500-750 J/KG MLCAPE) WHERE DIURNAL HEATING IS MOST LIKELY TO BE A CONTRIBUTING FACTOR IN ADVANCE OF THE AFOREMENTIONED FROPA. THE LATEST WRF-NMM SIMULATED REFLECTIVITY PRODUCT INDICATES A BROKEN LINE OF CONVECTION DEVELOPING NEAR OR JUST SOUTH OF THE VA BORDER AND PROGRESSING SOUTH/SW THROUGH CENTRAL NC IN ADVANCE OF THE BACK DOOR FRONT BETWEEN ROUGHLY 09-12Z. WITH THE ABOVE IN MIND... WILL INDICATE ISOLD TO SCT SHOWERS/STORMS ACROSS THE AREA THROUGH ~15Z...WITH THE BEST CHANCE IN THE NORTHERN PIEDMONT EARLY THIS MORNING...TRANSITIONING TO THE WEST/SW PIEDMONT BY MID MORNING. AFTER ~15Z...A COOL/STABLE AIRMASS ADVECTING INTO THE AREA FROM THE NORTHEAST IN THE WAKE OF THE FRONT WILL EFFECTIVELY END PRECIP CHANCES. HOWEVER...DEPENDING ON THE SPEED/PROGRESS OF THE BACK DOOR FRONT...ISOLD CONVECTION MAY REMAIN POSSIBLE INTO THE AFTERNOON IN THE FAR WEST/SW PIEDMONT AT THE EASTERN FRINGE OF THE INSTABILITY GRADIENT. EXPECT PRECIP CHANCES NEAR ~0 EVEN IN THE WEST/SW PIEDMONT BY 00Z THIS EVENING THROUGH SUNRISE TUE MORNING. TEMPERATURES: CHALLENGING TEMPERATURE FCST WITH A POTENTIAL TO BUST HIGHS BY 5-10F. HIGHS TODAY WILL DEPEND ENTIRELY ON THE TIMING OF THE BACKDOOR COLD FRONTAL PASSAGE. THE LATEST 00Z GUIDANCE INDICATES HIGHS RANGING FROM THE LOWER/MID 60S IN NORTHEAST NC (I.E. ELIZABETH CITY/AHOSKIE) TO THE LOWER/MID 80S IN WEST/SOUTHWEST NC. WILL INDICATE HIGHS RANGING FROM THE UPPER 60S/NEAR 70F IN THE FAR NORTHEAST COASTAL PLAIN TO THE LOWER/MID 80S IN THE FAR SW PIEDMONT. LOWS TONIGHT WILL BE EQUALLY CHALLENGING GIVEN THAT THE FRONT IS EXPECTED TO STALL JUST WEST OF CENTRAL NC. EXPECT LOWS TO RANGE FROM THE UPPER 30S/LOWER 40S IN THE E/NE COASTAL PLAIN TO THE LOWER 50S IN THE WEST/SW PIEDMONT. SEVERE THREAT: 0-6KM BULK SHEAR VALUES IN THE 40-50 KT RANGE ARE SUPPORTIVE OF SUPERCELLS...THOUGH SEVERE WEATHER APPEARS UNLIKELY THROUGH SUNRISE GIVEN BAD DIURNAL TIMING AND LITTLE IN THE WAY OF INSTABILITY. IN FACT...STRONG NW FLOW ALOFT WILL LIKELY SHEAR APART ANY CONVECTION THAT DEVELOPS PRIOR TO SUNRISE. HOWEVER...AN ISOLD SEVERE THREAT (HAIL/WIND) WILL BE POSSIBLE IN THE SW PIEDMONT BETWEEN 12-18Z WHERE INCREASING BOUNDARY LAYER MOISTURE AND DIURNAL HEATING IN ADVANCE OF THE BACK DOOR FRONT WILL ALLOW MARGINAL DESTABILIZATION TO OCCUR IN THE PRESENCE OF 0-6KM BULK SHEAR VALUES SUPPORTIVE OF SUPERCELLS. ALTHOUGH 07Z SPC MESOANALYSIS INDICATED 300-400 M2/S2 OF 0-1 KM SRH OVER CENTRAL NC...THE LATEST RUC GUIDANCE SHOWS 0-1KM SRH RAPIDLY DIMINISHING TO LESS THAN 100 M2/S2 AFTER SUNRISE. THE RELATIVE BEST CHANCE OF SEVERE WEATHER IS EXPECTED TO REMAIN SOUTH AND WEST OF THE AREA IN SC AND SOUTHWEST NC TODAY...WHERE A MORE DIURNALLY FAVORABLE FROPA WILL OCCUR. -VINCENT && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 330 AM MONDAY... THE STALLED FRONTAL ZONE WEST OF THE AREA WILL PROGRESS BACK TO THE NORTHEAST AS A WARM FRONT ON TUE...AND EXPECT HIGHS TO BE MORE HOMOGENEOUS THAN TODAY. GIVEN THE LIKELY PRESENCE OF SCT/BKN CLOUD COVER BETWEEN 2000-4000 FT AGL IN ASSOC/W WARM ADVECTION...AND THAT THE WARM FRONT WILL PROGRESS THROUGH THE AREA FROM SW-NE...EXPECT HIGHS RANGING FROM THE MID 70S IN THE WEST/SW PIEDMONT TO THE UPPER 60S/LOWER 70S IN THE COASTAL PLAIN...THOUGH THIS WILL HIGHLY DEPEND ON CLOUD COVER AND THE TIMING OF THE WARM FRONTAL PASSAGE. GIVEN THE CLOSE PROXIMITY OF THE AFOREMENTIONED UPPER LEVEL RIDGE JUST WEST OF CENTRAL NC AND A SUBSIDENCE INVERSION IN PLACE...IT MAY BE DIFFICULT FOR CONVECTION TO DEVELOP DURING THE DAY TUE. HOWEVER...THE RIDGE IS EXPECTED TO WEAKEN TUE NIGHT...WITH A POTENTIAL FOR UPPER LEVEL DISTURBANCES PROGRESSING INTO THE AREA VIA W/NW FLOW ALOFT. AS A RESULT...WILL CONTINUE TO INDICATE A SLIGHT CHANCE OF SHOWERS/STORMS TUE NIGHT. GIVEN WARM ADVECTION OVERNIGHT...EXPECT LOWS IN THE MID TO UPPER 50S. -VINCENT && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 315 AM MONDAY... ANOTHER UPPER TROUGH WILL DEVELOP OVER THE NORTHEAST US WEDNESDAY...WHILE AN UPPER LOW OVER THE SOUTHWEST LIFTS NORTHEAST BELOW THE UPPER RIDGE. THE WARM FROM FORECAST TO LIFT THROUGH CENTRAL NC TUESDAY WILL STALL AND SHOULD STRETCH FROM THE MIDWEST ACROSS THE MID ATLANTIC STATES WEDNESDAY MORNING...THEN BEGIN TO PUSH SOUTH THROUGH VA WEDNESDAY AFTERNOON AS THE AFOREMENTIONED UPPER TROUGH DIGS ACROSS NEW ENGLAND. AHEAD OF THE FRONT...DEEP LAYER WESTERLY FLOW SHOULD KEEP MUCH CENTRAL NC DRY WEDNESDAY...BUT THE PRESENCE OF A PREFRONTAL LEE TROUGH AND THE POTENTIAL FOR A WEAK UPPER DISTURBANCE ALOFT AND CONVECTIVE OUTFLOW BOUNDARIES FROM THE NORTH WARRANTS AT LEAST A LOW END CHANCE POP. FORECAST SOUNDINGS SHOW RELATIVELY WEAK MID LEVEL LAPSE RATES AND DEEP LAYER SHEAR...BUT LOW LEVEL LAPSE RATES WILL LIKELY BE RATHER STEEP AND COULD SUPPORT AN ISOLATED STRONG TO SEVERE WIND THREAT. THE WESTERLY FLOW WILL ALSO PUSH TEMPS THEIR HIGHEST VALUES OF THE WEEK WEDNESDAY. DEEPER MIXING TO 850MB OR ABOVE WOULD YIELD HIGHS IN THE LOW TO MID 80S...WHICH STATISTICAL GUIDANCE HAS BEEN CREEPING TOWARD OVER THE PAST FEW RUNS. RECORD HIGHS FOR WEDNESDAY ARE 86/87 AT GSO/RDU AND MAY BE JUST OUT OF REACH. MODELS ARE IN DECENT AGREEMENT ON THE FRONT PUSHING BACKDOOR THROUGH THE CWA WEDNESDAYS NIGHT AS HIGH PRESSURE BUILDS SOUTH OVER THE GREAT LAKES. HOW FAR SOUTH THE FRONT FINALLY SETTLES WILL DETERMINE WHETHER OR NOT THERE IS SUFFICIENT INSTABILITY TO SUPPORT CONVECTION THURSDAY INTO FRIDAY AS THE UPPER LOW DRIFTING EAST BENEATH THE RIDGE MOVES TOWARD THE TN VALLEY REGION. THE UPPER LOW IS FORECAST TO WEAKEN AND DROP SOUTHEAST ACROSS GA/SC ON FRIDAY...WHILE GFS FORECAST SOUNDINGS SHOW THE POTENTIAL FOR A WEAK DAMMING EVENT OVER NC. THE GREAT LAKES HIGH IS FORECAST TO BE MODESTLY STRONG AT 1025+ MB WHILE IT SHIFTS EAST ACROSS NEW ENGLAND...SO WE SHOULD SE A PERIOD OF AT OR SLIGHTLY BELOW NORMAL TEMPS THURSDAY THROUGH SATURDAY..WITH A WARMING TREND THROUGH THE END OF THE WEEKEND AS THE NEXT LOW PRESSURE SYSTEM ORGANIZES OVER THE NORTH CENTRAL US. WE WILL KEEP POPS MOSTLY IN LINE WITH HPC THURSDAY AND FRIDAY WITH HIGHER CHANCES TO THE SOUTH. && .AVIATION /18Z MONDAY THROUGH FRIDAY/... AS OF 145 PM MONDAY... 24-HR TAF PERIOD: VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. AHEAD OF THE BACKDOOR COLD FRONT WINDS WILL BE NNW AT 5-10 KT...WITH WINDS BEHIND THE FRONT NNE AT 10-15 KT GUSTING UP TO 20 KT. EXPECT GUSTS TO DIE DOWN AROUND SUNSET...WITH MAINLY EASTERLY WINDS AT 5 KTS OR LESS ACROSS ALL TERMINALS THROUGH SUNRISE. SKIES WILL BE MAINLY CLEAR OVERNIGHT WITH THE EXCEPTION OF SOME SCATTERED CLOUDS AT KINT AND KGSO. SHOULD SEE SOME BROKEN CIGS AROUND 3500 FT MOVING INTO THE AREA FROM WEST TO EAST...STARTING AROUND 08Z AT KINT AND KGSO AND MAKING IT TOWARD KRWI AT THE END OF THE TAF PERIOD. LOOKING AHEAD: MVFR CEILINGS ARE PROGGED TO DEVELOP EARLY TUE MORNING (06-12Z) IN VICINITY OF THE STALLED FRONT OVER UPSTATE SC AND SOUTHWEST NC. MVFR CEILINGS MAY MAKE THEIR WAY INTO THE AREA FROM SW-NE OR W-E AS THE STALLED FRONT LIFTS BACK THROUGH CENTRAL NC AS A WARM FRONT DURING THE DAY TUE. A PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE EARLY WED MORNING (06-12Z) IN ASSOC/W WARM ADVECTION UNDER THE NOCTURNAL INVERSION. ISOLD TO SCT SHOWERS AND STORMS ARE EXPECTED DURING THE DAY WED IN ADVANCE OF ANOTHER BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTH. A PROLONGED PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE THU THROUGH FRI IN ASSOC/W LOW-LEVEL NORTHEAST FLOW IN THE WAKE OF THE AFOREMENTIONED COLD FRONT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...KC/VINCENT SHORT TERM...VINCENT LONG TERM...SMITH AVIATION...KC/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
149 AM EDT MON APR 2 2012 .SYNOPSIS... A BACK DOOR COLD FRONT WILL PUSH SOUTHWEST THROUGH THE AREA TODAY BEFORE STALLING OUT OVER THE WESTERN CAROLINAS TONIGHT. THE STALLED BOUNDARY WILL LIFT NORTHEAST THROUGH CENTRAL NORTH CAROLINA AS A WARM FRONT DURING THE DAY TUESDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1039 AM MONDAY... UPDATE: CLEARING ALONG THE I-40 CORRIDOR HAS ALLOWED TEMPS TO REACH THE LOW TO MID 70S IN THAT AREA. CLOUD COVER ACROSS THE SOUTHWEST AND ALONG THE NC/VA BORDER HAVE KEPT TEMPS IN THE MID 60S. AS OF 14Z THE BACKDOOR COLD FRONT WAS STRETCHED FROM DANVILLE VA SOUTH AND EAST ACROSS THE AREA...HANGING OUT JUST EAST OF RDU... SMITHFIELD... AND GOLDSBORO. DEWPOINTS BEHIND THE FRONT ARE CRASHING INTO THE 40S AND LOW 50S...WITH TEMPS IN THE LOW TO MID 60S. SOME LIGHT SHOWERS HAVE STARTED IMPINGE ON THE SOUTHWESTERN EXTENT OF THE AREA. THIS CLOUD COVER AND SHOWERS MAY ACT TO KEEP TEMPS FROM RISING AS HIGH AS PREVIOUSLY THOUGHT...THUS HAVE LOWERED HIGH ACROSS THE SOUTHWEST TO AROUND 81 DEGREES. WITH THE CLEARING ACROSS THE I-40 CORRIDOR AND TEMPS ALREADY IN THE LOW 70S HAVE INCREASED HIGHS SLIGHTLY TO THE MID 70S. PREVIOUS DISCUSSION: OVERVIEW: SURFACE HIGH PRESSURE WILL STRENGTHEN OVER THE OH VALLEY AND MID-ATLANTIC TODAY/TONIGHT AS AN AMPLIFYING UPPER LEVEL TROUGH DIGS SOUTHEAST OFF THE MID-ATLANTIC COAST AND AN UPPER LEVEL RIDGE PROGRESSES FROM THE MS RIVER VALLEY INTO THE APPALACHIANS. PRESSURE RISES UPSTREAM OF THE AREA WILL HELP PUSH A BACK DOOR COLD FRONT (EXTENDING WEST-EAST THROUGH THE OH VALLEY AND NORTHERN VIRGINIAS AT 06Z) SOUTH/SW THROUGH CENTRAL NC TODAY...BEFORE STALLING OUT IN FAR WESTERN NC AND UPSTATE SC TONIGHT. PRECIPITATION CHANCES: UPSTREAM CONVECTION OVER KY/WV/VA AT 06Z APPEARS TO BE DRIVEN BY A COMBINATION OF WEAK LOW-LEVEL CONVERGENCE (IN VICINITY OF) AND WARM ADVECTION (JUST AHEAD OF) THE AFOREMENTIONED FRONTAL ZONE...WITH LITTLE OR NO HELP ALOFT. 06Z SPC MESOANALYSIS INDICATED NO MORE THAN 100-250 J/KG OF MUCAPE OVER CENTRAL NC...WITH THE BEST INSTABILITY (~1000 J/KG MUCAPE) OVER CENTRAL TN/KY IN THE PRESENCE OF MORE FAVORABLE BOUNDARY LAYER MOISTURE (SFC DEWPOINTS UPPER 50S) AND STEEPER MID-LEVEL LAPSE RATES (7-8 C/KM). AS A RESULT...EXPECT CONVECTION UPSTREAM OF THE AREA TO GENERALLY WEAKEN THROUGH 09Z AS SPEEDY NORTHWEST FLOW ALOFT PUSHES ACTIVITY AWAY FROM THE BEST LOW-LEVEL FORCING AND INTO A GENERALLY UNFAVORABLE THERMODYNAMIC ENVIRONMENT OVER THE NC PIEDMONT. HOWEVER...A RESPECTABLE (25 KFT ECHO TOPS) CONVECTIVE CELL THAT DEVELOPED JUST SOUTH OF DANVILLE ~07Z SUGGESTS THAT SUBTLE UPPER LEVEL FORCING IS PRESENT...AND/OR THAT DEEP-LAYER SHEAR (40-50 KT) SUPPORTIVE OF UPDRAFT ROTATION MAY BE ENHANCING UPDRAFTS. AS THE BACK DOOR COLD FRONT APPROACHES THE AREA FROM THE N/NE THROUGH 12Z...LOW-LEVEL MOISTURE WILL BEGIN TO INCREASE...AND SOME MARGINAL DESTABILIZATION IS EXPECTED. DESTABILIZATION WILL BE MOST PROMINENT IN THE FAR SOUTHWEST PIEDMONT (PERHAPS 500-750 J/KG MLCAPE) WHERE DIURNAL HEATING IS MOST LIKELY TO BE A CONTRIBUTING FACTOR IN ADVANCE OF THE AFOREMENTIONED FROPA. THE LATEST WRF-NMM SIMULATED REFLECTIVITY PRODUCT INDICATES A BROKEN LINE OF CONVECTION DEVELOPING NEAR OR JUST SOUTH OF THE VA BORDER AND PROGRESSING SOUTH/SW THROUGH CENTRAL NC IN ADVANCE OF THE BACK DOOR FRONT BETWEEN ROUGHLY 09-12Z. WITH THE ABOVE IN MIND... WILL INDICATE ISOLD TO SCT SHOWERS/STORMS ACROSS THE AREA THROUGH ~15Z...WITH THE BEST CHANCE IN THE NORTHERN PIEDMONT EARLY THIS MORNING...TRANSITIONING TO THE WEST/SW PIEDMONT BY MID MORNING. AFTER ~15Z...A COOL/STABLE AIRMASS ADVECTING INTO THE AREA FROM THE NORTHEAST IN THE WAKE OF THE FRONT WILL EFFECTIVELY END PRECIP CHANCES. HOWEVER...DEPENDING ON THE SPEED/PROGRESS OF THE BACK DOOR FRONT...ISOLD CONVECTION MAY REMAIN POSSIBLE INTO THE AFTERNOON IN THE FAR WEST/SW PIEDMONT AT THE EASTERN FRINGE OF THE INSTABILITY GRADIENT. EXPECT PRECIP CHANCES NEAR ~0 EVEN IN THE WEST/SW PIEDMONT BY 00Z THIS EVENING THROUGH SUNRISE TUE MORNING. TEMPERATURES: CHALLENGING TEMPERATURE FCST WITH A POTENTIAL TO BUST HIGHS BY 5-10F. HIGHS TODAY WILL DEPEND ENTIRELY ON THE TIMING OF THE BACKDOOR COLD FRONTAL PASSAGE. THE LATEST 00Z GUIDANCE INDICATES HIGHS RANGING FROM THE LOWER/MID 60S IN NORTHEAST NC (I.E. ELIZABETH CITY/AHOSKIE) TO THE LOWER/MID 80S IN WEST/SOUTHWEST NC. WILL INDICATE HIGHS RANGING FROM THE UPPER 60S/NEAR 70F IN THE FAR NORTHEAST COASTAL PLAIN TO THE LOWER/MID 80S IN THE FAR SW PIEDMONT. LOWS TONIGHT WILL BE EQUALLY CHALLENGING GIVEN THAT THE FRONT IS EXPECTED TO STALL JUST WEST OF CENTRAL NC. EXPECT LOWS TO RANGE FROM THE UPPER 30S/LOWER 40S IN THE E/NE COASTAL PLAIN TO THE LOWER 50S IN THE WEST/SW PIEDMONT. SEVERE THREAT: 0-6KM BULK SHEAR VALUES IN THE 40-50 KT RANGE ARE SUPPORTIVE OF SUPERCELLS...THOUGH SEVERE WEATHER APPEARS UNLIKELY THROUGH SUNRISE GIVEN BAD DIURNAL TIMING AND LITTLE IN THE WAY OF INSTABILITY. IN FACT...STRONG NW FLOW ALOFT WILL LIKELY SHEAR APART ANY CONVECTION THAT DEVELOPS PRIOR TO SUNRISE. HOWEVER...AN ISOLD SEVERE THREAT (HAIL/WIND) WILL BE POSSIBLE IN THE SW PIEDMONT BETWEEN 12-18Z WHERE INCREASING BOUNDARY LAYER MOISTURE AND DIURNAL HEATING IN ADVANCE OF THE BACK DOOR FRONT WILL ALLOW MARGINAL DESTABILIZATION TO OCCUR IN THE PRESENCE OF 0-6KM BULK SHEAR VALUES SUPPORTIVE OF SUPERCELLS. ALTHOUGH 07Z SPC MESOANALYSIS INDICATED 300-400 M2/S2 OF 0-1 KM SRH OVER CENTRAL NC...THE LATEST RUC GUIDANCE SHOWS 0-1KM SRH RAPIDLY DIMINISHING TO LESS THAN 100 M2/S2 AFTER SUNRISE. THE RELATIVE BEST CHANCE OF SEVERE WEATHER IS EXPECTED TO REMAIN SOUTH AND WEST OF THE AREA IN SC AND SOUTHWEST NC TODAY...WHERE A MORE DIURNALLY FAVORABLE FROPA WILL OCCUR. -VINCENT && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 330 AM MONDAY... THE STALLED FRONTAL ZONE WEST OF THE AREA WILL PROGRESS BACK TO THE NORTHEAST AS A WARM FRONT ON TUE...AND EXPECT HIGHS TO BE MORE HOMOGENEOUS THAN TODAY. GIVEN THE LIKELY PRESENCE OF SCT/BKN CLOUD COVER BETWEEN 2000-4000 FT AGL IN ASSOC/W WARM ADVECTION...AND THAT THE WARM FRONT WILL PROGRESS THROUGH THE AREA FROM SW-NE...EXPECT HIGHS RANGING FROM THE MID 70S IN THE WEST/SW PIEDMONT TO THE UPPER 60S/LOWER 70S IN THE COASTAL PLAIN...THOUGH THIS WILL HIGHLY DEPEND ON CLOUD COVER AND THE TIMING OF THE WARM FRONTAL PASSAGE. GIVEN THE CLOSE PROXIMITY OF THE AFOREMENTIONED UPPER LEVEL RIDGE JUST WEST OF CENTRAL NC AND A SUBSIDENCE INVERSION IN PLACE...IT MAY BE DIFFICULT FOR CONVECTION TO DEVELOP DURING THE DAY TUE. HOWEVER...THE RIDGE IS EXPECTED TO WEAKEN TUE NIGHT...WITH A POTENTIAL FOR UPPER LEVEL DISTURBANCES PROGRESSING INTO THE AREA VIA W/NW FLOW ALOFT. AS A RESULT...WILL CONTINUE TO INDICATE A SLIGHT CHANCE OF SHOWERS/STORMS TUE NIGHT. GIVEN WARM ADVECTION OVERNIGHT...EXPECT LOWS IN THE MID TO UPPER 50S. -VINCENT && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 315 AM MONDAY... ANOTHER UPPER TROUGH WILL DEVELOP OVER THE NORTHEAST US WEDNESDAY...WHILE AN UPPER LOW OVER THE SOUTHWEST LIFTS NORTHEAST BELOW THE UPPER RIDGE. THE WARM FROM FORECAST TO LIFT THROUGH CENTRAL NC TUESDAY WILL STALL AND SHOULD STRETCH FROM THE MIDWEST ACROSS THE MID ATLANTIC STATES WEDNESDAY MORNING...THEN BEGIN TO PUSH SOUTH THROUGH VA WEDNESDAY AFTERNOON AS THE AFOREMENTIONED UPPER TROUGH DIGS ACROSS NEW ENGLAND. AHEAD OF THE FRONT...DEEP LAYER WESTERLY FLOW SHOULD KEEP MUCH CENTRAL NC DRY WEDNESDAY...BUT THE PRESENCE OF A PREFRONTAL LEE TROUGH AND THE POTENTIAL FOR A WEAK UPPER DISTURBANCE ALOFT AND CONVECTIVE OUTFLOW BOUNDARIES FROM THE NORTH WARRANTS AT LEAST A LOW END CHANCE POP. FORECAST SOUNDINGS SHOW RELATIVELY WEAK MID LEVEL LAPSE RATES AND DEEP LAYER SHEAR...BUT LOW LEVEL LAPSE RATES WILL LIKELY BE RATHER STEEP AND COULD SUPPORT AN ISOLATED STRONG TO SEVERE WIND THREAT. THE WESTERLY FLOW WILL ALSO PUSH TEMPS THEIR HIGHEST VALUES OF THE WEEK WEDNESDAY. DEEPER MIXING TO 850MB OR ABOVE WOULD YIELD HIGHS IN THE LOW TO MID 80S...WHICH STATISTICAL GUIDANCE HAS BEEN CREEPING TOWARD OVER THE PAST FEW RUNS. RECORD HIGHS FOR WEDNESDAY ARE 86/87 AT GSO/RDU AND MAY BE JUST OUT OF REACH. MODELS ARE IN DECENT AGREEMENT ON THE FRONT PUSHING BACKDOOR THROUGH THE CWA WEDNESDAYS NIGHT AS HIGH PRESSURE BUILDS SOUTH OVER THE GREAT LAKES. HOW FAR SOUTH THE FRONT FINALLY SETTLES WILL DETERMINE WHETHER OR NOT THERE IS SUFFICIENT INSTABILITY TO SUPPORT CONVECTION THURSDAY INTO FRIDAY AS THE UPPER LOW DRIFTING EAST BENEATH THE RIDGE MOVES TOWARD THE TN VALLEY REGION. THE UPPER LOW IS FORECAST TO WEAKEN AND DROP SOUTHEAST ACROSS GA/SC ON FRIDAY...WHILE GFS FORECAST SOUNDINGS SHOW THE POTENTIAL FOR A WEAK DAMMING EVENT OVER NC. THE GREAT LAKES HIGH IS FORECAST TO BE MODESTLY STRONG AT 1025+ MB WHILE IT SHIFTS EAST ACROSS NEW ENGLAND...SO WE SHOULD SE A PERIOD OF AT OR SLIGHTLY BELOW NORMAL TEMPS THURSDAY THROUGH SATURDAY..WITH A WARMING TREND THROUGH THE END OF THE WEEKEND AS THE NEXT LOW PRESSURE SYSTEM ORGANIZES OVER THE NORTH CENTRAL US. WE WILL KEEP POPS MOSTLY IN LINE WITH HPC THURSDAY AND FRIDAY WITH HIGHER CHANCES TO THE SOUTH. && .AVIATION /18Z MONDAY THROUGH FRIDAY/... AS OF 145 PM MONDAY... 24-HR TAF PERIOD: VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. AHEAD OF THE BACKDOOR COLD FRONT WINDS WILL BE NNW AT 5-10 KT...WITH WINDS BEHIND THE FRONT NNE AT 10-15 KT GUSTING UP TO 20 KT. EXPECT GUSTS TO DIE DOWN AROUND SUNSET...WITH MAINLY EASTERLY WINDS AT 5 KTS OR LESS ACROSS ALL TERMINALS THROUGH SUNRISE. SKIES WILL BE MAINLY CLEAR OVERNIGHT WITH THE EXCEPTION OF SOME SCATTERED CLOUDS AT KINT AND KGSO. SHOULD SEE SOME BROKEN CIGS AROUND 3500 FT MOVING INTO THE AREA FROM WEST TO EAST...STARTING AROUND 08Z AT KINT AND KGSO AND MAKING IT TOWARD KRWI AT THE END OF THE TAF PERIOD. LOOKING AHEAD: MVFR CEILINGS ARE PROGGED TO DEVELOP EARLY TUE MORNING (06-12Z) IN VICINITY OF THE STALLED FRONT OVER UPSTATE SC AND SOUTHWEST NC. MVFR CEILINGS MAY MAKE THEIR WAY INTO THE AREA FROM SW-NE OR W-E AS THE STALLED FRONT LIFTS BACK THROUGH CENTRAL NC AS A WARM FRONT DURING THE DAY TUE. A PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE EARLY WED MORNING (06-12Z) IN ASSOC/W WARM ADVECTION UNDER THE NOCTURNAL INVERSION. ISOLD TO SCT SHOWERS AND STORMS ARE EXPECTED DURING THE DAY WED IN ADVANCE OF ANOTHER BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTH. A PROLONGED PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE THU THROUGH FRI IN ASSOC/W LOW-LEVEL NORTHEAST FLOW IN THE WAKE OF THE AFOREMENTIONED COLD FRONT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...KC/VINCENT SHORT TERM...VINCENT LONG TERM...SMITH AVIATION...KC/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1039 AM EDT MON APR 2 2012 .SYNOPSIS... A BACK DOOR COLD FRONT WILL PUSH SOUTHWEST THROUGH THE AREA TODAY BEFORE STALLING OUT OVER THE WESTERN CAROLINAS TONIGHT. THE STALLED BOUNDARY WILL LIFT NORTHEAST THROUGH CENTRAL NORTH CAROLINA AS A WARM FRONT DURING THE DAY TUESDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1039 AM MONDAY... UPDATE: CLEARING ALONG THE I-40 CORRIDOR HAS ALLOWED TEMPS TO REACH THE LOW TO MID 70S IN THAT AREA. CLOUD COVER ACROSS THE SOUTHWEST AND ALONG THE NC/VA BORDER HAVE KEPT TEMPS IN THE MID 60S. AS OF 14Z THE BACKDOOR COLD FRONT WAS STRETCHED FROM DANVILLE VA SOUTH AND EAST ACROSS THE AREA...HANGING OUT JUST EAST OF RDU... SMITHFIELD... AND GOLDSBORO. DEWPOINTS BEHIND THE FRONT ARE CRASHING INTO THE 40S AND LOW 50S...WITH TEMPS IN THE LOW TO MID 60S. SOME LIGHT SHOWERS HAVE STARTED IMPINGE ON THE SOUTHWESTERN EXTENT OF THE AREA. THIS CLOUD COVER AND SHOWERS MAY ACT TO KEEP TEMPS FROM RISING AS HIGH AS PREVIOUSLY THOUGHT...THUS HAVE LOWERED HIGH ACROSS THE SOUTHWEST TO AROUND 81 DEGREES. WITH THE CLEARING ACROSS THE I-40 CORRIDOR AND TEMPS ALREADY IN THE LOW 70S HAVE INCREASED HIGHS SLIGHTLY TO THE MID 70S. PREVIOUS DISCUSSION: OVERVIEW: SURFACE HIGH PRESSURE WILL STRENGTHEN OVER THE OH VALLEY AND MID-ATLANTIC TODAY/TONIGHT AS AN AMPLIFYING UPPER LEVEL TROUGH DIGS SOUTHEAST OFF THE MID-ATLANTIC COAST AND AN UPPER LEVEL RIDGE PROGRESSES FROM THE MS RIVER VALLEY INTO THE APPALACHIANS. PRESSURE RISES UPSTREAM OF THE AREA WILL HELP PUSH A BACK DOOR COLD FRONT (EXTENDING WEST-EAST THROUGH THE OH VALLEY AND NORTHERN VIRGINIAS AT 06Z) SOUTH/SW THROUGH CENTRAL NC TODAY...BEFORE STALLING OUT IN FAR WESTERN NC AND UPSTATE SC TONIGHT. PRECIPITATION CHANCES: UPSTREAM CONVECTION OVER KY/WV/VA AT 06Z APPEARS TO BE DRIVEN BY A COMBINATION OF WEAK LOW-LEVEL CONVERGENCE (IN VICINITY OF) AND WARM ADVECTION (JUST AHEAD OF) THE AFOREMENTIONED FRONTAL ZONE...WITH LITTLE OR NO HELP ALOFT. 06Z SPC MESOANALYSIS INDICATED NO MORE THAN 100-250 J/KG OF MUCAPE OVER CENTRAL NC...WITH THE BEST INSTABILITY (~1000 J/KG MUCAPE) OVER CENTRAL TN/KY IN THE PRESENCE OF MORE FAVORABLE BOUNDARY LAYER MOISTURE (SFC DEWPOINTS UPPER 50S) AND STEEPER MID-LEVEL LAPSE RATES (7-8 C/KM). AS A RESULT...EXPECT CONVECTION UPSTREAM OF THE AREA TO GENERALLY WEAKEN THROUGH 09Z AS SPEEDY NORTHWEST FLOW ALOFT PUSHES ACTIVITY AWAY FROM THE BEST LOW-LEVEL FORCING AND INTO A GENERALLY UNFAVORABLE THERMODYNAMIC ENVIRONMENT OVER THE NC PIEDMONT. HOWEVER...A RESPECTABLE (25 KFT ECHO TOPS) CONVECTIVE CELL THAT DEVELOPED JUST SOUTH OF DANVILLE ~07Z SUGGESTS THAT SUBTLE UPPER LEVEL FORCING IS PRESENT...AND/OR THAT DEEP-LAYER SHEAR (40-50 KT) SUPPORTIVE OF UPDRAFT ROTATION MAY BE ENHANCING UPDRAFTS. AS THE BACK DOOR COLD FRONT APPROACHES THE AREA FROM THE N/NE THROUGH 12Z...LOW-LEVEL MOISTURE WILL BEGIN TO INCREASE...AND SOME MARGINAL DESTABILIZATION IS EXPECTED. DESTABILIZATION WILL BE MOST PROMINENT IN THE FAR SOUTHWEST PIEDMONT (PERHAPS 500-750 J/KG MLCAPE) WHERE DIURNAL HEATING IS MOST LIKELY TO BE A CONTRIBUTING FACTOR IN ADVANCE OF THE AFOREMENTIONED FROPA. THE LATEST WRF-NMM SIMULATED REFLECTIVITY PRODUCT INDICATES A BROKEN LINE OF CONVECTION DEVELOPING NEAR OR JUST SOUTH OF THE VA BORDER AND PROGRESSING SOUTH/SW THROUGH CENTRAL NC IN ADVANCE OF THE BACK DOOR FRONT BETWEEN ROUGHLY 09-12Z. WITH THE ABOVE IN MIND... WILL INDICATE ISOLD TO SCT SHOWERS/STORMS ACROSS THE AREA THROUGH ~15Z...WITH THE BEST CHANCE IN THE NORTHERN PIEDMONT EARLY THIS MORNING...TRANSITIONING TO THE WEST/SW PIEDMONT BY MID MORNING. AFTER ~15Z...A COOL/STABLE AIRMASS ADVECTING INTO THE AREA FROM THE NORTHEAST IN THE WAKE OF THE FRONT WILL EFFECTIVELY END PRECIP CHANCES. HOWEVER...DEPENDING ON THE SPEED/PROGRESS OF THE BACK DOOR FRONT...ISOLD CONVECTION MAY REMAIN POSSIBLE INTO THE AFTERNOON IN THE FAR WEST/SW PIEDMONT AT THE EASTERN FRINGE OF THE INSTABILITY GRADIENT. EXPECT PRECIP CHANCES NEAR ~0 EVEN IN THE WEST/SW PIEDMONT BY 00Z THIS EVENING THROUGH SUNRISE TUE MORNING. TEMPERATURES: CHALLENGING TEMPERATURE FCST WITH A POTENTIAL TO BUST HIGHS BY 5-10F. HIGHS TODAY WILL DEPEND ENTIRELY ON THE TIMING OF THE BACKDOOR COLD FRONTAL PASSAGE. THE LATEST 00Z GUIDANCE INDICATES HIGHS RANGING FROM THE LOWER/MID 60S IN NORTHEAST NC (I.E. ELIZABETH CITY/AHOSKIE) TO THE LOWER/MID 80S IN WEST/SOUTHWEST NC. WILL INDICATE HIGHS RANGING FROM THE UPPER 60S/NEAR 70F IN THE FAR NORTHEAST COASTAL PLAIN TO THE LOWER/MID 80S IN THE FAR SW PIEDMONT. LOWS TONIGHT WILL BE EQUALLY CHALLENGING GIVEN THAT THE FRONT IS EXPECTED TO STALL JUST WEST OF CENTRAL NC. EXPECT LOWS TO RANGE FROM THE UPPER 30S/LOWER 40S IN THE E/NE COASTAL PLAIN TO THE LOWER 50S IN THE WEST/SW PIEDMONT. SEVERE THREAT: 0-6KM BULK SHEAR VALUES IN THE 40-50 KT RANGE ARE SUPPORTIVE OF SUPERCELLS...THOUGH SEVERE WEATHER APPEARS UNLIKELY THROUGH SUNRISE GIVEN BAD DIURNAL TIMING AND LITTLE IN THE WAY OF INSTABILITY. IN FACT...STRONG NW FLOW ALOFT WILL LIKELY SHEAR APART ANY CONVECTION THAT DEVELOPS PRIOR TO SUNRISE. HOWEVER...AN ISOLD SEVERE THREAT (HAIL/WIND) WILL BE POSSIBLE IN THE SW PIEDMONT BETWEEN 12-18Z WHERE INCREASING BOUNDARY LAYER MOISTURE AND DIURNAL HEATING IN ADVANCE OF THE BACK DOOR FRONT WILL ALLOW MARGINAL DESTABILIZATION TO OCCUR IN THE PRESENCE OF 0-6KM BULK SHEAR VALUES SUPPORTIVE OF SUPERCELLS. ALTHOUGH 07Z SPC MESOANALYSIS INDICATED 300-400 M2/S2 OF 0-1 KM SRH OVER CENTRAL NC...THE LATEST RUC GUIDANCE SHOWS 0-1KM SRH RAPIDLY DIMINISHING TO LESS THAN 100 M2/S2 AFTER SUNRISE. THE RELATIVE BEST CHANCE OF SEVERE WEATHER IS EXPECTED TO REMAIN SOUTH AND WEST OF THE AREA IN SC AND SOUTHWEST NC TODAY...WHERE A MORE DIURNALLY FAVORABLE FROPA WILL OCCUR. -VINCENT && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 330 AM MONDAY... THE STALLED FRONTAL ZONE WEST OF THE AREA WILL PROGRESS BACK TO THE NORTHEAST AS A WARM FRONT ON TUE...AND EXPECT HIGHS TO BE MORE HOMOGENEOUS THAN TODAY. GIVEN THE LIKELY PRESENCE OF SCT/BKN CLOUD COVER BETWEEN 2000-4000 FT AGL IN ASSOC/W WARM ADVECTION...AND THAT THE WARM FRONT WILL PROGRESS THROUGH THE AREA FROM SW-NE...EXPECT HIGHS RANGING FROM THE MID 70S IN THE WEST/SW PIEDMONT TO THE UPPER 60S/LOWER 70S IN THE COASTAL PLAIN...THOUGH THIS WILL HIGHLY DEPEND ON CLOUD COVER AND THE TIMING OF THE WARM FRONTAL PASSAGE. GIVEN THE CLOSE PROXIMITY OF THE AFOREMENTIONED UPPER LEVEL RIDGE JUST WEST OF CENTRAL NC AND A SUBSIDENCE INVERSION IN PLACE...IT MAY BE DIFFICULT FOR CONVECTION TO DEVELOP DURING THE DAY TUE. HOWEVER...THE RIDGE IS EXPECTED TO WEAKEN TUE NIGHT...WITH A POTENTIAL FOR UPPER LEVEL DISTURBANCES PROGRESSING INTO THE AREA VIA W/NW FLOW ALOFT. AS A RESULT...WILL CONTINUE TO INDICATE A SLIGHT CHANCE OF SHOWERS/STORMS TUE NIGHT. GIVEN WARM ADVECTION OVERNIGHT...EXPECT LOWS IN THE MID TO UPPER 50S. -VINCENT && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 315 AM MONDAY... ANOTHER UPPER TROUGH WILL DEVELOP OVER THE NORTHEAST US WEDNESDAY...WHILE AN UPPER LOW OVER THE SOUTHWEST LIFTS NORTHEAST BELOW THE UPPER RIDGE. THE WARM FROM FORECAST TO LIFT THROUGH CENTRAL NC TUESDAY WILL STALL AND SHOULD STRETCH FROM THE MIDWEST ACROSS THE MID ATLANTIC STATES WEDNESDAY MORNING...THEN BEGIN TO PUSH SOUTH THROUGH VA WEDNESDAY AFTERNOON AS THE AFOREMENTIONED UPPER TROUGH DIGS ACROSS NEW ENGLAND. AHEAD OF THE FRONT...DEEP LAYER WESTERLY FLOW SHOULD KEEP MUCH CENTRAL NC DRY WEDNESDAY...BUT THE PRESENCE OF A PREFRONTAL LEE TROUGH AND THE POTENTIAL FOR A WEAK UPPER DISTURBANCE ALOFT AND CONVECTIVE OUTFLOW BOUNDARIES FROM THE NORTH WARRANTS AT LEAST A LOW END CHANCE POP. FORECAST SOUNDINGS SHOW RELATIVELY WEAK MID LEVEL LAPSE RATES AND DEEP LAYER SHEAR...BUT LOW LEVEL LAPSE RATES WILL LIKELY BE RATHER STEEP AND COULD SUPPORT AN ISOLATED STRONG TO SEVERE WIND THREAT. THE WESTERLY FLOW WILL ALSO PUSH TEMPS THEIR HIGHEST VALUES OF THE WEEK WEDNESDAY. DEEPER MIXING TO 850MB OR ABOVE WOULD YIELD HIGHS IN THE LOW TO MID 80S...WHICH STATISTICAL GUIDANCE HAS BEEN CREEPING TOWARD OVER THE PAST FEW RUNS. RECORD HIGHS FOR WEDNESDAY ARE 86/87 AT GSO/RDU AND MAY BE JUST OUT OF REACH. MODELS ARE IN DECENT AGREEMENT ON THE FRONT PUSHING BACKDOOR THROUGH THE CWA WEDNESDAYS NIGHT AS HIGH PRESSURE BUILDS SOUTH OVER THE GREAT LAKES. HOW FAR SOUTH THE FRONT FINALLY SETTLES WILL DETERMINE WHETHER OR NOT THERE IS SUFFICIENT INSTABILITY TO SUPPORT CONVECTION THURSDAY INTO FRIDAY AS THE UPPER LOW DRIFTING EAST BENEATH THE RIDGE MOVES TOWARD THE TN VALLEY REGION. THE UPPER LOW IS FORECAST TO WEAKEN AND DROP SOUTHEAST ACROSS GA/SC ON FRIDAY...WHILE GFS FORECAST SOUNDINGS SHOW THE POTENTIAL FOR A WEAK DAMMING EVENT OVER NC. THE GREAT LAKES HIGH IS FORECAST TO BE MODESTLY STRONG AT 1025+ MB WHILE IT SHIFTS EAST ACROSS NEW ENGLAND...SO WE SHOULD SE A PERIOD OF AT OR SLIGHTLY BELOW NORMAL TEMPS THURSDAY THROUGH SATURDAY..WITH A WARMING TREND THROUGH THE END OF THE WEEKEND AS THE NEXT LOW PRESSURE SYSTEM ORGANIZES OVER THE NORTH CENTRAL US. WE WILL KEEP POPS MOSTLY IN LINE WITH HPC THURSDAY AND FRIDAY WITH HIGHER CHANCES TO THE SOUTH. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 635 AM MONDAY... 24-HR TAF PERIOD: A BACKDOOR COLD FRONT WILL APPROACH THE AREA FROM THE NORTH THROUGH 12Z...THEN PROGRESS SOUTHWEST THROUGH CENTRAL NC TODAY. THE FRONT IS EXPECTED TO STALL OUT OVER WESTERN NC/SC LATER THIS EVENING. EXPECT A POTENTIAL FOR MVFR CONDITIONS ASSOC/W ISOLD CONVECTION THIS MORNING (BETWEEN ROUGHLY 12-17Z) AND A PERIOD OF MVFR CEILINGS ALONG/BEHIND THE BACKDOOR COLD FRONT BETWEEN 13-19Z. OTHERWISE... EXPECT VFR CONDITIONS TO PREDOMINATE. SOUTHWESTERLY WINDS AT 5-10 KT AT THE BEGINNING OF THE TAF PERIOD WILL BECOME WESTERLY BY OR SHORTLY AFTER 12Z...THEN VEER TO THE NORTH/NORTHEAST AND INCREASE TO 10-15 KT WITH GUSTS UP TO 20 KT IN ASSOC/W THE BACKDOOR COLD FRONTAL PASSAGE BETWEEN ROUGHLY 13-18Z. WINDS WILL BECOME EASTERLY AT ~5 KT OR LIGHT/VARIABLE FROM SUNSET THIS EVENING THROUGH SUNRISE TUE MORNING. LOOKING AHEAD: MVFR CEILINGS ARE PROGGED TO DEVELOP EARLY TUE MORNING (06-12Z) IN VICINITY OF THE STALLED FRONT OVER UPSTATE SC AND SOUTHWEST NC. THERE IS A GOOD PROBABILITY THAT MVFR CEILINGS WILL OVERSPREAD THE AREA FROM SW-NE OR W-E AS THE STALLED FRONT LIFTS BACK THROUGH CENTRAL NC AS A WARM FRONT DURING THE DAY TUE. A PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE EARLY WED MORNING (06-12Z) IN ASSOC/W WARM ADVECTION UNDER THE NOCTURNAL INVERSION. ISOLD TO SCT SHOWERS AND STORMS ARE EXPECTED DURING THE DAY WED IN ADVANCE OF ANOTHER BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTH. A PROLONGED PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE THU THROUGH FRI IN ASSOC/W LOW-LEVEL NORTHEAST FLOW IN THE WAKE OF THE AFOREMENTIONED COLD FRONT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...KC/VINCENT SHORT TERM...VINCENT LONG TERM...SMITH AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
639 AM EDT MON APR 2 2012 .SYNOPSIS... A BACK DOOR COLD FRONT WILL PUSH SOUTHWEST THROUGH THE AREA TODAY BEFORE STALLING OUT OVER THE WESTERN CAROLINAS TONIGHT. THE STALLED BOUNDARY WILL LIFT NORTHEAST THROUGH CENTRAL NORTH CAROLINA AS A WARM FRONT DURING THE DAY TUESDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 325 AM MONDAY... OVERVIEW: SURFACE HIGH PRESSURE WILL STRENGTHEN OVER THE OH VALLEY AND MID-ATLANTIC TODAY/TONIGHT AS AN AMPLIFYING UPPER LEVEL TROUGH DIGS SOUTHEAST OFF THE MID-ATLANTIC COAST AND AN UPPER LEVEL RIDGE PROGRESSES FROM THE MS RIVER VALLEY INTO THE APPALACHIANS. PRESSURE RISES UPSTREAM OF THE AREA WILL HELP PUSH A BACK DOOR COLD FRONT (EXTENDING WEST-EAST THROUGH THE OH VALLEY AND NORTHERN VIRGINIAS AT 06Z) SOUTH/SW THROUGH CENTRAL NC TODAY...BEFORE STALLING OUT IN FAR WESTERN NC AND UPSTATE SC TONIGHT. PRECIPITATION CHANCES: UPSTREAM CONVECTION OVER KY/WV/VA AT 06Z APPEARS TO BE DRIVEN BY A COMBINATION OF WEAK LOW-LEVEL CONVERGENCE (IN VICINITY OF) AND WARM ADVECTION (JUST AHEAD OF) THE AFOREMENTIONED FRONTAL ZONE...WITH LITTLE OR NO HELP ALOFT. 06Z SPC MESOANALYSIS INDICATED NO MORE THAN 100-250 J/KG OF MUCAPE OVER CENTRAL NC...WITH THE BEST INSTABILITY (~1000 J/KG MUCAPE) OVER CENTRAL TN/KY IN THE PRESENCE OF MORE FAVORABLE BOUNDARY LAYER MOISTURE (SFC DEWPOINTS UPPER 50S) AND STEEPER MID-LEVEL LAPSE RATES (7-8 C/KM). AS A RESULT...EXPECT CONVECTION UPSTREAM OF THE AREA TO GENERALLY WEAKEN THROUGH 09Z AS SPEEDY NORTHWEST FLOW ALOFT PUSHES ACTIVITY AWAY FROM THE BEST LOW-LEVEL FORCING AND INTO A GENERALLY UNFAVORABLE THERMODYNAMIC ENVIRONMENT OVER THE NC PIEDMONT. HOWEVER...A RESPECTABLE (25 KFT ECHO TOPS) CONVECTIVE CELL THAT DEVELOPED JUST SOUTH OF DANVILLE ~07Z SUGGESTS THAT SUBTLE UPPER LEVEL FORCING IS PRESENT...AND/OR THAT DEEP-LAYER SHEAR (40-50 KT) SUPPORTIVE OF UPDRAFT ROTATION MAY BE ENHANCING UPDRAFTS. AS THE BACK DOOR COLD FRONT APPROACHES THE AREA FROM THE N/NE THROUGH 12Z...LOW-LEVEL MOISTURE WILL BEGIN TO INCREASE...AND SOME MARGINAL DESTABILIZATION IS EXPECTED. DESTABILIZATION WILL BE MOST PROMINENT IN THE FAR SOUTHWEST PIEDMONT (PERHAPS 500-750 J/KG MLCAPE) WHERE DIURNAL HEATING IS MOST LIKELY TO BE A CONTRIBUTING FACTOR IN ADVANCE OF THE AFOREMENTIONED FROPA. THE LATEST WRF-NMM SIMULATED REFLECTIVITY PRODUCT INDICATES A BROKEN LINE OF CONVECTION DEVELOPING NEAR OR JUST SOUTH OF THE VA BORDER AND PROGRESSING SOUTH/SW THROUGH CENTRAL NC IN ADVANCE OF THE BACK DOOR FRONT BETWEEN ROUGHLY 09-12Z. WITH THE ABOVE IN MIND... WILL INDICATE ISOLD TO SCT SHOWERS/STORMS ACROSS THE AREA THROUGH ~15Z...WITH THE BEST CHANCE IN THE NORTHERN PIEDMONT EARLY THIS MORNING...TRANSITIONING TO THE WEST/SW PIEDMONT BY MID MORNING. AFTER ~15Z...A COOL/STABLE AIRMASS ADVECTING INTO THE AREA FROM THE NORTHEAST IN THE WAKE OF THE FRONT WILL EFFECTIVELY END PRECIP CHANCES. HOWEVER...DEPENDING ON THE SPEED/PROGRESS OF THE BACK DOOR FRONT...ISOLD CONVECTION MAY REMAIN POSSIBLE INTO THE AFTERNOON IN THE FAR WEST/SW PIEDMONT AT THE EASTERN FRINGE OF THE INSTABILITY GRADIENT. EXPECT PRECIP CHANCES NEAR ~0 EVEN IN THE WEST/SW PIEDMONT BY 00Z THIS EVENING THROUGH SUNRISE TUE MORNING. TEMPERATURES: CHALLENGING TEMPERATURE FCST WITH A POTENTIAL TO BUST HIGHS BY 5-10F. HIGHS TODAY WILL DEPEND ENTIRELY ON THE TIMING OF THE BACKDOOR COLD FRONTAL PASSAGE. THE LATEST 00Z GUIDANCE INDICATES HIGHS RANGING FROM THE LOWER/MID 60S IN NORTHEAST NC (I.E. ELIZABETH CITY/AHOSKIE) TO THE LOWER/MID 80S IN WEST/SOUTHWEST NC. WILL INDICATE HIGHS RANGING FROM THE UPPER 60S/NEAR 70F IN THE FAR NORTHEAST COASTAL PLAIN TO THE LOWER/MID 80S IN THE FAR SW PIEDMONT. LOWS TONIGHT WILL BE EQUALLY CHALLENGING GIVEN THAT THE FRONT IS EXPECTED TO STALL JUST WEST OF CENTRAL NC. EXPECT LOWS TO RANGE FROM THE UPPER 30S/LOWER 40S IN THE E/NE COASTAL PLAIN TO THE LOWER 50S IN THE WEST/SW PIEDMONT. SEVERE THREAT: 0-6KM BULK SHEAR VALUES IN THE 40-50 KT RANGE ARE SUPPORTIVE OF SUPERCELLS...THOUGH SEVERE WEATHER APPEARS UNLIKELY THROUGH SUNRISE GIVEN BAD DIURNAL TIMING AND LITTLE IN THE WAY OF INSTABILITY. IN FACT...STRONG NW FLOW ALOFT WILL LIKELY SHEAR APART ANY CONVECTION THAT DEVELOPS PRIOR TO SUNRISE. HOWEVER...AN ISOLD SEVERE THREAT (HAIL/WIND) WILL BE POSSIBLE IN THE SW PIEDMONT BETWEEN 12-18Z WHERE INCREASING BOUNDARY LAYER MOISTURE AND DIURNAL HEATING IN ADVANCE OF THE BACK DOOR FRONT WILL ALLOW MARGINAL DESTABILIZATION TO OCCUR IN THE PRESENCE OF 0-6KM BULK SHEAR VALUES SUPPORTIVE OF SUPERCELLS. ALTHOUGH 07Z SPC MESOANALYSIS INDICATED 300-400 M2/S2 OF 0-1 KM SRH OVER CENTRAL NC...THE LATEST RUC GUIDANCE SHOWS 0-1KM SRH RAPIDLY DIMINISHING TO LESS THAN 100 M2/S2 AFTER SUNRISE. THE RELATIVE BEST CHANCE OF SEVERE WEATHER IS EXPECTED TO REMAIN SOUTH AND WEST OF THE AREA IN SC AND SOUTHWEST NC TODAY...WHERE A MORE DIURNALLY FAVORABLE FROPA WILL OCCUR. -VINCENT && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 330 AM MONDAY... THE STALLED FRONTAL ZONE WEST OF THE AREA WILL PROGRESS BACK TO THE NORTHEAST AS A WARM FRONT ON TUE...AND EXPECT HIGHS TO BE MORE HOMOGENEOUS THAN TODAY. GIVEN THE LIKELY PRESENCE OF SCT/BKN CLOUD COVER BETWEEN 2000-4000 FT AGL IN ASSOC/W WARM ADVECTION...AND THAT THE WARM FRONT WILL PROGRESS THROUGH THE AREA FROM SW-NE...EXPECT HIGHS RANGING FROM THE MID 70S IN THE WEST/SW PIEDMONT TO THE UPPER 60S/LOWER 70S IN THE COASTAL PLAIN...THOUGH THIS WILL HIGHLY DEPEND ON CLOUD COVER AND THE TIMING OF THE WARM FRONTAL PASSAGE. GIVEN THE CLOSE PROXIMITY OF THE AFOREMENTIONED UPPER LEVEL RIDGE JUST WEST OF CENTRAL NC AND A SUBSIDENCE INVERSION IN PLACE...IT MAY BE DIFFICULT FOR CONVECTION TO DEVELOP DURING THE DAY TUE. HOWEVER...THE RIDGE IS EXPECTED TO WEAKEN TUE NIGHT...WITH A POTENTIAL FOR UPPER LEVEL DISTURBANCES PROGRESSING INTO THE AREA VIA W/NW FLOW ALOFT. AS A RESULT...WILL CONTINUE TO INDICATE A SLIGHT CHANCE OF SHOWERS/STORMS TUE NIGHT. GIVEN WARM ADVECTION OVERNIGHT...EXPECT LOWS IN THE MID TO UPPER 50S. -VINCENT && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 315 AM MONDAY... ANOTHER UPPER TROUGH WILL DEVELOP OVER THE NORTHEAST US WEDNESDAY...WHILE AN UPPER LOW OVER THE SOUTHWEST LIFTS NORTHEAST BELOW THE UPPER RIDGE. THE WARM FROM FORECAST TO LIFT THROUGH CENTRAL NC TUESDAY WILL STALL AND SHOULD STRETCH FROM THE MIDWEST ACROSS THE MID ATLANTIC STATES WEDNESDAY MORNING...THEN BEGIN TO PUSH SOUTH THROUGH VA WEDNESDAY AFTERNOON AS THE AFOREMENTIONED UPPER TROUGH DIGS ACROSS NEW ENGLAND. AHEAD OF THE FRONT...DEEP LAYER WESTERLY FLOW SHOULD KEEP MUCH CENTRAL NC DRY WEDNESDAY...BUT THE PRESENCE OF A PREFRONTAL LEE TROUGH AND THE POTENTIAL FOR A WEAK UPPER DISTURBANCE ALOFT AND CONVECTIVE OUTFLOW BOUNDARIES FROM THE NORTH WARRANTS AT LEAST A LOW END CHANCE POP. FORECAST SOUNDINGS SHOW RELATIVELY WEAK MID LEVEL LAPSE RATES AND DEEP LAYER SHEAR...BUT LOW LEVEL LAPSE RATES WILL LIKELY BE RATHER STEEP AND COULD SUPPORT AN ISOLATED STRONG TO SEVERE WIND THREAT. THE WESTERLY FLOW WILL ALSO PUSH TEMPS THEIR HIGHEST VALUES OF THE WEEK WEDNESDAY. DEEPER MIXING TO 850MB OR ABOVE WOULD YIELD HIGHS IN THE LOW TO MID 80S...WHICH STATISTICAL GUIDANCE HAS BEEN CREEPING TOWARD OVER THE PAST FEW RUNS. RECORD HIGHS FOR WEDNESDAY ARE 86/87 AT GSO/RDU AND MAY BE JUST OUT OF REACH. MODELS ARE IN DECENT AGREEMENT ON THE FRONT PUSHING BACKDOOR THROUGH THE CWA WEDNESDAYS NIGHT AS HIGH PRESSURE BUILDS SOUTH OVER THE GREAT LAKES. HOW FAR SOUTH THE FRONT FINALLY SETTLES WILL DETERMINE WHETHER OR NOT THERE IS SUFFICIENT INSTABILITY TO SUPPORT CONVECTION THURSDAY INTO FRIDAY AS THE UPPER LOW DRIFTING EAST BENEATH THE RIDGE MOVES TOWARD THE TN VALLEY REGION. THE UPPER LOW IS FORECAST TO WEAKEN AND DROP SOUTHEAST ACROSS GA/SC ON FRIDAY...WHILE GFS FORECAST SOUNDINGS SHOW THE POTENTIAL FOR A WEAK DAMMING EVENT OVER NC. THE GREAT LAKES HIGH IS FORECAST TO BE MODESTLY STRONG AT 1025+ MB WHILE IT SHIFTS EAST ACROSS NEW ENGLAND...SO WE SHOULD SE A PERIOD OF AT OR SLIGHTLY BELOW NORMAL TEMPS THURSDAY THROUGH SATURDAY..WITH A WARMING TREND THROUGH THE END OF THE WEEKEND AS THE NEXT LOW PRESSURE SYSTEM ORGANIZES OVER THE NORTH CENTRAL US. WE WILL KEEP POPS MOSTLY IN LINE WITH HPC THURSDAY AND FRIDAY WITH HIGHER CHANCES TO THE SOUTH. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 635 AM MONDAY... 24-HR TAF PERIOD: A BACKDOOR COLD FRONT WILL APPROACH THE AREA FROM THE NORTH THROUGH 12Z...THEN PROGRESS SOUTHWEST THROUGH CENTRAL NC TODAY. THE FRONT IS EXPECTED TO STALL OUT OVER WESTERN NC/SC LATER THIS EVENING. EXPECT A POTENTIAL FOR MVFR CONDITIONS ASSOC/W ISOLD CONVECTION THIS MORNING (BETWEEN ROUGHLY 12-17Z) AND A PERIOD OF MVFR CEILINGS ALONG/BEHIND THE BACKDOOR COLD FRONT BETWEEN 13-19Z. OTHERWISE... EXPECT VFR CONDITIONS TO PREDOMINATE. SOUTHWESTERLY WINDS AT 5-10 KT AT THE BEGINNING OF THE TAF PERIOD WILL BECOME WESTERLY BY OR SHORTLY AFTER 12Z...THEN VEER TO THE NORTH/NORTHEAST AND INCREASE TO 10-15 KT WITH GUSTS UP TO 20 KT IN ASSOC/W THE BACKDOOR COLD FRONTAL PASSAGE BETWEEN ROUGHLY 13-18Z. WINDS WILL BECOME EASTERLY AT ~5 KT OR LIGHT/VARIABLE FROM SUNSET THIS EVENING THROUGH SUNRISE TUE MORNING. LOOKING AHEAD: MVFR CEILINGS ARE PROGGED TO DEVELOP EARLY TUE MORNING (06-12Z) IN VICINITY OF THE STALLED FRONT OVER UPSTATE SC AND SOUTHWEST NC. THERE IS A GOOD PROBABILITY THAT MVFR CEILINGS WILL OVERSPREAD THE AREA FROM SW-NE OR W-E AS THE STALLED FRONT LIFTS BACK THROUGH CENTRAL NC AS A WARM FRONT DURING THE DAY TUE. A PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE EARLY WED MORNING (06-12Z) IN ASSOC/W WARM ADVECTION UNDER THE NOCTURNAL INVERSION. ISOLD TO SCT SHOWERS AND STORMS ARE EXPECTED DURING THE DAY WED IN ADVANCE OF ANOTHER BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTH. A PROLONGED PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE THU THROUGH FRI IN ASSOC/W LOW-LEVEL NORTHEAST FLOW IN THE WAKE OF THE AFOREMENTIONED COLD FRONT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...SMITH AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
426 AM EDT MON APR 2 2012 .SYNOPSIS... A BACK DOOR COLD FRONT WILL PUSH SOUTHWEST THROUGH THE AREA TODAY BEFORE STALLING OUT OVER THE WESTERN CAROLINAS TONIGHT. THE STALLED BOUNDARY WILL LIFT NORTHEAST THROUGH CENTRAL NORTH CAROLINA AS A WARM FRONT DURING THE DAY TUESDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 325 AM MONDAY... OVERVIEW: SURFACE HIGH PRESSURE WILL STRENGTHEN OVER THE OH VALLEY AND MID-ATLANTIC TODAY/TONIGHT AS AN AMPLIFYING UPPER LEVEL TROUGH DIGS SOUTHEAST OFF THE MID-ATLANTIC COAST AND AN UPPER LEVEL RIDGE PROGRESSES FROM THE MS RIVER VALLEY INTO THE APPALACHIANS. PRESSURE RISES UPSTREAM OF THE AREA WILL HELP PUSH A BACK DOOR COLD FRONT (EXTENDING WEST-EAST THROUGH THE OH VALLEY AND NORTHERN VIRGINIAS AT 06Z) SOUTH/SW THROUGH CENTRAL NC TODAY...BEFORE STALLING OUT IN FAR WESTERN NC AND UPSTATE SC TONIGHT. PRECIPITATION CHANCES: UPSTREAM CONVECTION OVER KY/WV/VA AT 06Z APPEARS TO BE DRIVEN BY A COMBINATION OF WEAK LOW-LEVEL CONVERGENCE (IN VICINITY OF) AND WARM ADVECTION (JUST AHEAD OF) THE AFOREMENTIONED FRONTAL ZONE...WITH LITTLE OR NO HELP ALOFT. 06Z SPC MESOANALYSIS INDICATED NO MORE THAN 100-250 J/KG OF MUCAPE OVER CENTRAL NC...WITH THE BEST INSTABILITY (~1000 J/KG MUCAPE) OVER CENTRAL TN/KY IN THE PRESENCE OF MORE FAVORABLE BOUNDARY LAYER MOISTURE (SFC DEWPOINTS UPPER 50S) AND STEEPER MID-LEVEL LAPSE RATES (7-8 C/KM). AS A RESULT...EXPECT CONVECTION UPSTREAM OF THE AREA TO GENERALLY WEAKEN THROUGH 09Z AS SPEEDY NORTHWEST FLOW ALOFT PUSHES ACTIVITY AWAY FROM THE BEST LOW-LEVEL FORCING AND INTO A GENERALLY UNFAVORABLE THERMODYNAMIC ENVIRONMENT OVER THE NC PIEDMONT. HOWEVER...A RESPECTABLE (25 KFT ECHO TOPS) CONVECTIVE CELL THAT DEVELOPED JUST SOUTH OF DANVILLE ~07Z SUGGESTS THAT SUBTLE UPPER LEVEL FORCING IS PRESENT...AND/OR THAT DEEP-LAYER SHEAR (40-50 KT) SUPPORTIVE OF UPDRAFT ROTATION MAY BE ENHANCING UPDRAFTS. AS THE BACK DOOR COLD FRONT APPROACHES THE AREA FROM THE N/NE THROUGH 12Z...LOW-LEVEL MOISTURE WILL BEGIN TO INCREASE...AND SOME MARGINAL DESTABILIZATION IS EXPECTED. DESTABILIZATION WILL BE MOST PROMINENT IN THE FAR SOUTHWEST PIEDMONT (PERHAPS 500-750 J/KG MLCAPE) WHERE DIURNAL HEATING IS MOST LIKELY TO BE A CONTRIBUTING FACTOR IN ADVANCE OF THE AFOREMENTIONED FROPA. THE LATEST WRF-NMM SIMULATED REFLECTIVITY PRODUCT INDICATES A BROKEN LINE OF CONVECTION DEVELOPING NEAR OR JUST SOUTH OF THE VA BORDER AND PROGRESSING SOUTH/SW THROUGH CENTRAL NC IN ADVANCE OF THE BACK DOOR FRONT BETWEEN ROUGHLY 09-12Z. WITH THE ABOVE IN MIND... WILL INDICATE ISOLD TO SCT SHOWERS/STORMS ACROSS THE AREA THROUGH ~15Z...WITH THE BEST CHANCE IN THE NORTHERN PIEDMONT EARLY THIS MORNING...TRANSITIONING TO THE WEST/SW PIEDMONT BY MID MORNING. AFTER ~15Z...A COOL/STABLE AIRMASS ADVECTING INTO THE AREA FROM THE NORTHEAST IN THE WAKE OF THE FRONT WILL EFFECTIVELY END PRECIP CHANCES. HOWEVER...DEPENDING ON THE SPEED/PROGRESS OF THE BACK DOOR FRONT...ISOLD CONVECTION MAY REMAIN POSSIBLE INTO THE AFTERNOON IN THE FAR WEST/SW PIEDMONT AT THE EASTERN FRINGE OF THE INSTABILITY GRADIENT. EXPECT PRECIP CHANCES NEAR ~0 EVEN IN THE WEST/SW PIEDMONT BY 00Z THIS EVENING THROUGH SUNRISE TUE MORNING. TEMPERATURES: CHALLENGING TEMPERATURE FCST WITH A POTENTIAL TO BUST HIGHS BY 5-10F. HIGHS TODAY WILL DEPEND ENTIRELY ON THE TIMING OF THE BACKDOOR COLD FRONTAL PASSAGE. THE LATEST 00Z GUIDANCE INDICATES HIGHS RANGING FROM THE LOWER/MID 60S IN NORTHEAST NC (I.E. ELIZABETH CITY/AHOSKIE) TO THE LOWER/MID 80S IN WEST/SOUTHWEST NC. WILL INDICATE HIGHS RANGING FROM THE UPPER 60S/NEAR 70F IN THE FAR NORTHEAST COASTAL PLAIN TO THE LOWER/MID 80S IN THE FAR SW PIEDMONT. LOWS TONIGHT WILL BE EQUALLY CHALLENGING GIVEN THAT THE FRONT IS EXPECTED TO STALL JUST WEST OF CENTRAL NC. EXPECT LOWS TO RANGE FROM THE UPPER 30S/LOWER 40S IN THE E/NE COASTAL PLAIN TO THE LOWER 50S IN THE WEST/SW PIEDMONT. SEVERE THREAT: 0-6KM BULK SHEAR VALUES IN THE 40-50 KT RANGE ARE SUPPORTIVE OF SUPERCELLS...THOUGH SEVERE WEATHER APPEARS UNLIKELY THROUGH SUNRISE GIVEN BAD DIURNAL TIMING AND LITTLE IN THE WAY OF INSTABILITY. IN FACT...STRONG NW FLOW ALOFT WILL LIKELY SHEAR APART ANY CONVECTION THAT DEVELOPS PRIOR TO SUNRISE. HOWEVER...AN ISOLD SEVERE THREAT (HAIL/WIND) WILL BE POSSIBLE IN THE SW PIEDMONT BETWEEN 12-18Z WHERE INCREASING BOUNDARY LAYER MOISTURE AND DIURNAL HEATING IN ADVANCE OF THE BACK DOOR FRONT WILL ALLOW MARGINAL DESTABILIZATION TO OCCUR IN THE PRESENCE OF 0-6KM BULK SHEAR VALUES SUPPORTIVE OF SUPERCELLS. ALTHOUGH 07Z SPC MESOANALYSIS INDICATED 300-400 M2/S2 OF 0-1 KM SRH OVER CENTRAL NC...THE LATEST RUC GUIDANCE SHOWS 0-1KM SRH RAPIDLY DIMINISHING TO LESS THAN 100 M2/S2 AFTER SUNRISE. THE RELATIVE BEST CHANCE OF SEVERE WEATHER IS EXPECTED TO REMAIN SOUTH AND WEST OF THE AREA IN SC AND SOUTHWEST NC TODAY...WHERE A MORE DIURNALLY FAVORABLE FROPA WILL OCCUR. -VINCENT && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 330 AM MONDAY... THE STALLED FRONTAL ZONE WEST OF THE AREA WILL PROGRESS BACK TO THE NORTHEAST AS A WARM FRONT ON TUE...AND EXPECT HIGHS TO BE MORE HOMOGENEOUS THAN TODAY. GIVEN THE LIKELY PRESENCE OF SCT/BKN CLOUD COVER BETWEEN 2000-4000 FT AGL IN ASSOC/W WARM ADVECTION...AND THAT THE WARM FRONT WILL PROGRESS THROUGH THE AREA FROM SW-NE...EXPECT HIGHS RANGING FROM THE MID 70S IN THE WEST/SW PIEDMONT TO THE UPPER 60S/LOWER 70S IN THE COASTAL PLAIN...THOUGH THIS WILL HIGHLY DEPEND ON CLOUD COVER AND THE TIMING OF THE WARM FRONTAL PASSAGE. GIVEN THE CLOSE PROXIMITY OF THE AFOREMENTIONED UPPER LEVEL RIDGE JUST WEST OF CENTRAL NC AND A SUBSIDENCE INVERSION IN PLACE...IT MAY BE DIFFICULT FOR CONVECTION TO DEVELOP DURING THE DAY TUE. HOWEVER...THE RIDGE IS EXPECTED TO WEAKEN TUE NIGHT...WITH A POTENTIAL FOR UPPER LEVEL DISTURBANCES PROGRESSING INTO THE AREA VIA W/NW FLOW ALOFT. AS A RESULT...WILL CONTINUE TO INDICATE A SLIGHT CHANCE OF SHOWERS/STORMS TUE NIGHT. GIVEN WARM ADVECTION OVERNIGHT...EXPECT LOWS IN THE MID TO UPPER 50S. -VINCENT && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 315 AM MONDAY... ANOTHER UPPER TROUGH WILL DEVELOP OVER THE NORTHEAST US WEDNESDAY...WHILE AN UPPER LOW OVER THE SOUTHWEST LIFTS NORTHEAST BELOW THE UPPER RIDGE. THE WARM FROM FORECAST TO LIFT THROUGH CENTRAL NC TUESDAY WILL STALL AND SHOULD STRETCH FROM THE MIDWEST ACROSS THE MID ATLANTIC STATES WEDNESDAY MORNING...THEN BEGIN TO PUSH SOUTH THROUGH VA WEDNESDAY AFTERNOON AS THE AFOREMENTIONED UPPER TROUGH DIGS ACROSS NEW ENGLAND. AHEAD OF THE FRONT...DEEP LAYER WESTERLY FLOW SHOULD KEEP MUCH CENTRAL NC DRY WEDNESDAY...BUT THE PRESENCE OF A PREFRONTAL LEE TROUGH AND THE POTENTIAL FOR A WEAK UPPER DISTURBANCE ALOFT AND CONVECTIVE OUTFLOW BOUNDARIES FROM THE NORTH WARRANTS AT LEAST A LOW END CHANCE POP. FORECAST SOUNDINGS SHOW RELATIVELY WEAK MID LEVEL LAPSE RATES AND DEEP LAYER SHEAR...BUT LOW LEVEL LAPSE RATES WILL LIKELY BE RATHER STEEP AND COULD SUPPORT AN ISOLATED STRONG TO SEVERE WIND THREAT. THE WESTERLY FLOW WILL ALSO PUSH TEMPS THEIR HIGHEST VALUES OF THE WEEK WEDNESDAY. DEEPER MIXING TO 850MB OR ABOVE WOULD YIELD HIGHS IN THE LOW TO MID 80S...WHICH STATISTICAL GUIDANCE HAS BEEN CREEPING TOWARD OVER THE PAST FEW RUNS. RECORD HIGHS FOR WEDNESDAY ARE 86/87 AT GSO/RDU AND MAY BE JUST OUT OF REACH. MODELS ARE IN DECENT AGREEMENT ON THE FRONT PUSHING BACKDOOR THROUGH THE CWA WEDNESDAYS NIGHT AS HIGH PRESSURE BUILDS SOUTH OVER THE GREAT LAKES. HOW FAR SOUTH THE FRONT FINALLY SETTLES WILL DETERMINE WHETHER OR NOT THERE IS SUFFICIENT INSTABILITY TO SUPPORT CONVECTION THURSDAY INTO FRIDAY AS THE UPPER LOW DRIFTING EAST BENEATH THE RIDGE MOVES TOWARD THE TN VALLEY REGION. THE UPPER LOW IS FORECAST TO WEAKEN AND DROP SOUTHEAST ACROSS GA/SC ON FRIDAY...WHILE GFS FORECAST SOUNDINGS SHOW THE POTENTIAL FOR A WEAK DAMMING EVENT OVER NC. THE GREAT LAKES HIGH IS FORECAST TO BE MODESTLY STRONG AT 1025+ MB WHILE IT SHIFTS EAST ACROSS NEW ENGLAND...SO WE SHOULD SE A PERIOD OF AT OR SLIGHTLY BELOW NORMAL TEMPS THURSDAY THROUGH SATURDAY..WITH A WARMING TREND THROUGH THE END OF THE WEEKEND AS THE NEXT LOW PRESSURE SYSTEM ORGANIZES OVER THE NORTH CENTRAL US. WE WILL KEEP POPS MOSTLY IN LINE WITH HPC THURSDAY AND FRIDAY WITH HIGHER CHANCES TO THE SOUTH. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 425 AM MONDAY... 24-HR TAF PERIOD: A BACKDOOR COLD FRONT WILL APPROACH THE AREA FROM THE NORTH THROUGH 12Z...THEN PROGRESS SOUTHWEST THROUGH CENTRAL NC TODAY. THE FRONT IS EXPECTED TO STALL OUT OVER WESTERN NC/SC LATER THIS AFTERNOON AND EVENING. EXPECT A POTENTIAL FOR MVFR CONDITIONS ASSOC/W ISOLD CONVECTION THIS MORNING (BETWEEN ROUGHLY 09-15Z) AND A PERIOD OF MVFR CEILINGS ALONG/BEHIND THE BACKDOOR COLD FRONT BETWEEN 13-19Z. OTHERWISE...EXPECT VFR CONDITIONS TO PREDOMINATE. A ~35 KT WESTERLY LOW-LEVEL JET AT 1500-2000 FT MAY ALLOW FOR MARGINAL LOW-LEVEL WIND SHEAR BETWEEN 09-12Z THIS MORNING. HOWEVER...THE PRESENCE OF A 5-10 KT SOUTHWESTERLY BREEZE AT THE SURFACE SUGGESTS IT MAY BE DIFFICULT FOR SUSTAINED LLWS CRITERIA TO BE MET...DESPITE ~30 DEGREES OF VEERING AS WELL. TRANSIENT LOW-LEVEL WIND SHEAR WILL BE POSSIBLE IF SURFACE WINDS BECOME LIGHT/VARIABLE OR CALM...PARTICULARLY IN THE WAKE OF ANY ISOLD SHOWER ACTIVITY THAT MAY TEMPORARILY CREATE A STABLE COLD NEAR-SURFACE COLD POOL. SOUTHWESTERLY WINDS AT 5-10 KT AT THE BEGINNING OF THE TAF PERIOD WILL BECOME WESTERLY BY 12Z...THEN VEER TO THE NORTH/NORTHEAST AND INCREASE TO 10-15 KT IN ASSOC/W THE BACKDOOR COLD FRONTAL PASSAGE BETWEEN ROUGHLY 13-16Z. WINDS WILL BECOME EASTERLY AT ~5 KT OR LIGHT/ VARIABLE FROM SUNSET THIS EVENING THROUGH SUNRISE TUE MORNING. LOOKING AHEAD: MVFR CEILINGS ARE PROGGED TO DEVELOP EARLY TUE MORNING (06-12Z) IN VICINITY OF THE STALLED FRONT OVER UPSTATE SC AND SOUTHWEST NC. THERE IS A GOOD PROBABILITY THAT MVFR CEILINGS WILL OVERSPREAD THE AREA FROM SW-NE OR W-E AS THE STALLED FRONT LIFTS BACK THROUGH CENTRAL NC AS A WARM FRONT DURING THE DAY TUE. A PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE EARLY WED MORNING (06-12Z) IN ASSOC/W WARM ADVECTION UNDER THE NOCTURNAL INVERSION. ISOLD TO SCT SHOWERS AND STORMS ARE EXPECTED DURING THE DAY WED IN ADVANCE OF ANOTHER BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTH. A PROLONGED PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE THU THROUGH FRI IN ASSOC/W LOW-LEVEL NORTHEAST FLOW IN THE WAKE OF THE AFOREMENTIONED COLD FRONT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...SMITH AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
345 AM EDT MON APR 2 2012 .SYNOPSIS... A BACK DOOR COLD FRONT WILL PUSH SOUTHWEST THROUGH THE AREA TODAY BEFORE STALLING OUT OVER THE WESTERN CAROLINAS TONIGHT. THE STALLED BOUNDARY WILL LIFT NORTHEAST THROUGH CENTRAL NORTH CAROLINA AS A WARM FRONT DURING THE DAY TUESDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 325 AM MONDAY... OVERVIEW: SURFACE HIGH PRESSURE WILL STRENGTHEN OVER THE OH VALLEY AND MID-ATLANTIC TODAY/TONIGHT AS AN AMPLIFYING UPPER LEVEL TROUGH DIGS SOUTHEAST OFF THE MID-ATLANTIC COAST AND AN UPPER LEVEL RIDGE PROGRESSES FROM THE MS RIVER VALLEY INTO THE APPALACHIANS. PRESSURE RISES UPSTREAM OF THE AREA WILL HELP PUSH A BACK DOOR COLD FRONT (EXTENDING WEST-EAST THROUGH THE OH VALLEY AND NORTHERN VIRGINIAS AT 06Z) SOUTH/SW THROUGH CENTRAL NC TODAY...BEFORE STALLING OUT IN FAR WESTERN NC AND UPSTATE SC TONIGHT. PRECIPITATION CHANCES: UPSTREAM CONVECTION OVER KY/WV/VA AT 06Z APPEARS TO BE DRIVEN BY A COMBINATION OF WEAK LOW-LEVEL CONVERGENCE (IN VICINITY OF) AND WARM ADVECTION (JUST AHEAD OF) THE AFOREMENTIONED FRONTAL ZONE...WITH LITTLE OR NO HELP ALOFT. 06Z SPC MESOANALYSIS INDICATED NO MORE THAN 100-250 J/KG OF MUCAPE OVER CENTRAL NC...WITH THE BEST INSTABILITY (~1000 J/KG MUCAPE) OVER CENTRAL TN/KY IN THE PRESENCE OF MORE FAVORABLE BOUNDARY LAYER MOISTURE (SFC DEWPOINTS UPPER 50S) AND STEEPER MID-LEVEL LAPSE RATES (7-8 C/KM). AS A RESULT...EXPECT CONVECTION UPSTREAM OF THE AREA TO GENERALLY WEAKEN THROUGH 09Z AS SPEEDY NORTHWEST FLOW ALOFT PUSHES ACTIVITY AWAY FROM THE BEST LOW-LEVEL FORCING AND INTO A GENERALLY UNFAVORABLE THERMODYNAMIC ENVIRONMENT OVER THE NC PIEDMONT. HOWEVER...A RESPECTABLE (25 KFT ECHO TOPS) CONVECTIVE CELL THAT DEVELOPED JUST SOUTH OF DANVILLE ~07Z SUGGESTS THAT SUBTLE UPPER LEVEL FORCING IS PRESENT...AND/OR THAT DEEP-LAYER SHEAR (40-50 KT) SUPPORTIVE OF UPDRAFT ROTATION MAY BE ENHANCING UPDRAFTS. AS THE BACK DOOR COLD FRONT APPROACHES THE AREA FROM THE N/NE THROUGH 12Z...LOW-LEVEL MOISTURE WILL BEGIN TO INCREASE...AND SOME MARGINAL DESTABILIZATION IS EXPECTED. DESTABILIZATION WILL BE MOST PROMINENT IN THE FAR SOUTHWEST PIEDMONT (PERHAPS 500-750 J/KG MLCAPE) WHERE DIURNAL HEATING IS MOST LIKELY TO BE A CONTRIBUTING FACTOR IN ADVANCE OF THE AFOREMENTIONED FROPA. THE LATEST WRF-NMM SIMULATED REFLECTIVITY PRODUCT INDICATES A BROKEN LINE OF CONVECTION DEVELOPING NEAR OR JUST SOUTH OF THE VA BORDER AND PROGRESSING SOUTH/SW THROUGH CENTRAL NC IN ADVANCE OF THE BACK DOOR FRONT BETWEEN ROUGHLY 09-12Z. WITH THE ABOVE IN MIND... WILL INDICATE ISOLD TO SCT SHOWERS/STORMS ACROSS THE AREA THROUGH ~15Z...WITH THE BEST CHANCE IN THE NORTHERN PIEDMONT EARLY THIS MORNING...TRANSITIONING TO THE WEST/SW PIEDMONT BY MID MORNING. AFTER ~15Z...A COOL/STABLE AIRMASS ADVECTING INTO THE AREA FROM THE NORTHEAST IN THE WAKE OF THE FRONT WILL EFFECTIVELY END PRECIP CHANCES. HOWEVER...DEPENDING ON THE SPEED/PROGRESS OF THE BACK DOOR FRONT...ISOLD CONVECTION MAY REMAIN POSSIBLE INTO THE AFTERNOON IN THE FAR WEST/SW PIEDMONT AT THE EASTERN FRINGE OF THE INSTABILITY GRADIENT. EXPECT PRECIP CHANCES NEAR ~0 EVEN IN THE WEST/SW PIEDMONT BY 00Z THIS EVENING THROUGH SUNRISE TUE MORNING. TEMPERATURES: CHALLENGING TEMPERATURE FCST WITH A POTENTIAL TO BUST HIGHS BY 5-10F. HIGHS TODAY WILL DEPEND ENTIRELY ON THE TIMING OF THE BACKDOOR COLD FRONTAL PASSAGE. THE LATEST 00Z GUIDANCE INDICATES HIGHS RANGING FROM THE LOWER/MID 60S IN NORTHEAST NC (I.E. ELIZABETH CITY/AHOSKIE) TO THE LOWER/MID 80S IN WEST/SOUTHWEST NC. WILL INDICATE HIGHS RANGING FROM THE UPPER 60S/NEAR 70F IN THE FAR NORTHEAST COASTAL PLAIN TO THE LOWER/MID 80S IN THE FAR SW PIEDMONT. LOWS TONIGHT WILL BE EQUALLY CHALLENGING GIVEN THAT THE FRONT IS EXPECTED TO STALL JUST WEST OF CENTRAL NC. EXPECT LOWS TO RANGE FROM THE UPPER 30S/LOWER 40S IN THE E/NE COASTAL PLAIN TO THE LOWER 50S IN THE WEST/SW PIEDMONT. SEVERE THREAT: 0-6KM BULK SHEAR VALUES IN THE 40-50 KT RANGE ARE SUPPORTIVE OF SUPERCELLS...THOUGH SEVERE WEATHER APPEARS UNLIKELY THROUGH SUNRISE GIVEN BAD DIURNAL TIMING AND LITTLE IN THE WAY OF INSTABILITY. IN FACT...STRONG NW FLOW ALOFT WILL LIKELY SHEAR APART ANY CONVECTION THAT DEVELOPS PRIOR TO SUNRISE. HOWEVER...AN ISOLD SEVERE THREAT (HAIL/WIND) WILL BE POSSIBLE IN THE SW PIEDMONT BETWEEN 12-18Z WHERE INCREASING BOUNDARY LAYER MOISTURE AND DIURNAL HEATING IN ADVANCE OF THE BACK DOOR FRONT WILL ALLOW MARGINAL DESTABILIZATION TO OCCUR IN THE PRESENCE OF 0-6KM BULK SHEAR VALUES SUPPORTIVE OF SUPERCELLS. ALTHOUGH 07Z SPC MESOANALYSIS INDICATED 300-400 M2/S2 OF 0-1 KM SRH OVER CENTRAL NC...THE LATEST RUC GUIDANCE SHOWS 0-1KM SRH RAPIDLY DIMINISHING TO LESS THAN 100 M2/S2 AFTER SUNRISE. THE RELATIVE BEST CHANCE OF SEVERE WEATHER IS EXPECTED TO REMAIN SOUTH AND WEST OF THE AREA IN SC AND SOUTHWEST NC TODAY...WHERE A MORE DIURNALLY FAVORABLE FROPA WILL OCCUR. -VINCENT && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 330 AM MONDAY... THE STALLED FRONTAL ZONE WEST OF THE AREA WILL PROGRESS BACK TO THE NORTHEAST AS A WARM FRONT ON TUE...AND EXPECT HIGHS TO BE MORE HOMOGENEOUS THAN TODAY. GIVEN THE LIKELY PRESENCE OF SCT/BKN CLOUD COVER BETWEEN 2000-4000 FT AGL IN ASSOC/W WARM ADVECTION...AND THAT THE WARM FRONT WILL PROGRESS THROUGH THE AREA FROM SW-NE...EXPECT HIGHS RANGING FROM THE MID 70S IN THE WEST/SW PIEDMONT TO THE UPPER 60S/LOWER 70S IN THE COASTAL PLAIN...THOUGH THIS WILL HIGHLY DEPEND ON CLOUD COVER AND THE TIMING OF THE WARM FRONTAL PASSAGE. GIVEN THE CLOSE PROXIMITY OF THE AFOREMENTIONED UPPER LEVEL RIDGE JUST WEST OF CENTRAL NC AND A SUBSIDENCE INVERSION IN PLACE...IT MAY BE DIFFICULT FOR CONVECTION TO DEVELOP DURING THE DAY TUE. HOWEVER...THE RIDGE IS EXPECTED TO WEAKEN TUE NIGHT...WITH A POTENTIAL FOR UPPER LEVEL DISTURBANCES PROGRESSING INTO THE AREA VIA W/NW FLOW ALOFT. AS A RESULT...WILL CONTINUE TO INDICATE A SLIGHT CHANCE OF SHOWERS/STORMS TUE NIGHT. -VINCENT && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 315 AM MONDAY... ANOTHER UPPER TROUGH WILL DEVELOP OVER THE NORTHEAST US WEDNESDAY...WHILE AN UPPER LOW OVER THE SOUTHWEST LIFTS NORTHEAST BELOW THE UPPER RIDGE. THE WARM FROM FORECAST TO LIFT THROUGH CENTRAL NC TUESDAY WILL STALL AND SHOULD STRETCH FROM THE MIDWEST ACROSS THE MID ATLANTIC STATES WEDNESDAY MORNING...THEN BEGIN TO PUSH SOUTH THROUGH VA WEDNESDAY AFTERNOON AS THE AFOREMENTIONED UPPER TROUGH DIGS ACROSS NEW ENGLAND. AHEAD OF THE FRONT...DEEP LAYER WESTERLY FLOW SHOULD KEEP MUCH CENTRAL NC DRY WEDNESDAY...BUT THE PRESENCE OF A PREFRONTAL LEE TROUGH AND THE POTENTIAL FOR A WEAK UPPER DISTURBANCE ALOFT AND CONVECTIVE OUTFLOW BOUNDARIES FROM THE NORTH WARRANTS AT LEAST A LOW END CHANCE POP. FORECAST SOUNDINGS SHOW RELATIVELY WEAK MID LEVEL LAPSE RATES AND DEEP LAYER SHEAR...BUT LOW LEVEL LAPSE RATES WILL LIKELY BE RATHER STEEP AND COULD SUPPORT AN ISOLATED STRONG TO SEVERE WIND THREAT. THE WESTERLY FLOW WILL ALSO PUSH TEMPS THEIR HIGHEST VALUES OF THE WEEK WEDNESDAY. DEEPER MIXING TO 850MB OR ABOVE WOULD YIELD HIGHS IN THE LOW TO MID 80S...WHICH STATISTICAL GUIDANCE HAS BEEN CREEPING TOWARD OVER THE PAST FEW RUNS. RECORD HIGHS FOR WEDNESDAY ARE 86/87 AT GSO/RDU AND MAY BE JUST OUT OF REACH. MODELS ARE IN DECENT AGREEMENT ON THE FRONT PUSHING BACKDOOR THROUGH THE CWA WEDNESDAYS NIGHT AS HIGH PRESSURE BUILDS SOUTH OVER THE GREAT LAKES. HOW FAR SOUTH THE FRONT FINALLY SETTLES WILL DETERMINE WHETHER OR NOT THERE IS SUFFICIENT INSTABILITY TO SUPPORT CONVECTION THURSDAY INTO FRIDAY AS THE UPPER LOW DRIFTING EAST BENEATH THE RIDGE MOVES TOWARD THE TN VALLEY REGION. THE UPPER LOW IS FORECAST TO WEAKEN AND DROP SOUTHEAST ACROSS GA/SC ON FRIDAY...WHILE GFS FORECAST SOUNDINGS SHOW THE POTENTIAL FOR A WEAK DAMMING EVENT OVER NC. THE GREAT LAKES HIGH IS FORECAST TO BE MODESTLY STRONG AT 1025+ MB WHILE IT SHIFTS EAST ACROSS NEW ENGLAND...SO WE SHOULD SE A PERIOD OF AT OR SLIGHTLY BELOW NORMAL TEMPS THURSDAY THROUGH SATURDAY..WITH A WARMING TREND THROUGH THE END OF THE WEEKEND AS THE NEXT LOW PRESSURE SYSTEM ORGANIZES OVER THE NORTH CENTRAL US. WE WILL KEEP POPS MOSTLY IN LINE WITH HPC THURSDAY AND FRIDAY WITH HIGHER CHANCES TO THE SOUTH. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 215 AM MONDAY... 24-HR TAF PERIOD: A BACKDOOR COLD FRONT WILL APPROACH THE AREA FROM THE NORTH THROUGH 12Z...THEN PROGRESS SOUTHWEST THROUGH CENTRAL NC TODAY. THE FRONT IS EXPECTED TO STALL OUT OVER WESTERN NC/SC LATER THIS AFTERNOON AND EVENING. EXPECT A POTENTIAL FOR MVFR CONDITIONS ASSOC/W ISOLD CONVECTION THIS MORNING (BETWEEN ROUGHLY 09-15Z) AND A PERIOD OF MVFR CEILINGS ALONG/BEHIND THE BACKDOOR COLD FRONT BETWEEN 13-19Z. OTHERWISE...EXPECT VFR CONDITIONS TO PREDOMINATE. SOUTHWESTERLY WINDS AT 5-10 KT AT THE BEGINNING OF THE TAF PERIOD WILL BECOME WESTERLY BY 12Z...THEN VEER TO THE NORTH/NORTHEAST AND INCREASE TO 10-15 KT IN ASSOC/W THE BACKDOOR COLD FRONTAL PASSAGE BETWEEN ROUGHLY 13-16Z. WINDS WILL BECOME EASTERLY AT ~5 KT OR LIGHT/ VARIABLE FROM SUNSET THIS EVENING THROUGH SUNRISE TUE MORNING. LOOKING AHEAD: MVFR CEILINGS ARE PROGGED TO DEVELOP EARLY TUE MORNING (06-12Z) IN VICINITY OF THE STALLED FRONT OVER UPSTATE SC AND SOUTHWEST NC. THERE IS A GOOD PROBABILITY THAT MVFR CEILINGS WILL OVERSPREAD THE AREA FROM SW-NE OR W-E AS THE STALLED FRONT LIFTS BACK THROUGH CENTRAL NC AS A WARM FRONT DURING THE DAY TUE. A PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE EARLY WED MORNING (06-12Z) IN ASSOC/W WARM ADVECTION UNDER THE NOCTURNAL INVERSION. ISOLD TO SCT SHOWERS AND STORMS ARE EXPECTED DURING THE DAY WED IN ADVANCE OF ANOTHER BACKDOOR COLD FRONT APPROACHING THE AREA FROM THE NORTH. A PROLONGED PERIOD OF MVFR/IFR CEILINGS WILL BE POSSIBLE THU THROUGH FRI IN ASSOC/W LOW-LEVEL NORTHEAST FLOW IN THE WAKE OF THE AFOREMENTIONED COLD FRONT. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT LONG TERM...SMITH AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
152 AM EDT MON APR 2 2012 .SYNOPSIS... A WEAK COLD FRONT WILL DROP SOUTH ACROSS THE AREA TODAY AND MAY BRING AN ISOLATED SHOWER OR THUNDERSTORM. UNSETTLED CONDITIONS WILL RETURN BY MID WEEK AS A LOW PRESSURE SYSTEM APPROACHES THE EASTERN CAROLINAS. COOL AND DRY HIGH PRESSURE IS EXPECTED TO BUILD INTO THE REGION LATE IN THE WEEK AND PERSIST INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 1030 PM SUNDAY...CLUSTER OF SHOWERS AND ISOLATED TSTMS ASSOCIATED WITH AN UPPER LEVEL VORT...HAS NEARLY TRACKED ACROSS THE STATE OF SC THIS EVENING BEFORE FINALLY ENCOUNTERING A STABILIZING ATMOSPHERE AFTER SUNSET. IT IS ALSO ENCOUNTERING A SHALLOW STABLE LOW LEVEL MARINE AIR BEHIND A SEA BREEZE THAT TRACKED A GOOD 50 MILES INLAND BEFORE THE CIRCULATION WAS INTERRUPTED BY YOU GUESS IT...SUNSET. OVERALL...CONVECTION HAS NEARLY DIED OUT ENTIRELY WITH ONLY A FEW SHOWERS TEMPORARILY LEFT ACROSS SOUTHERN SC AT THE MOMENT. HAVE REMOVED ALL POPS FOR THIS EVENING...AND THE OVERNIGHT PERIOD. CONVECTION DROPPING SOUTHWARD ASSOCIATED WITH A SFC COLD FRONT WILL LIKELY HOLD OFF UNTIL AFTER SEVERAL HRS AFTER MONDAYS SUNRISE AT WHICH TIME THE ATM WILL BEGIN TO DESTABILIZE. CURRENT MIN TEMP FCST LOOKS AOK. NOT EXPECTING FOG TO BE A PROBLEM OVERNITE WITH A SFC SW-W WIND REMAINING ACTIVE OVERNIGHT. LATEST MIN FCST LOOKS AOK AND C NO REASON TO ALTER. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...BACK DOOR TYPE COLD FRONT WILL BE ON THE DOORSTEP OF THE NORTHERN PART OF THE CWA AT THE START OF THE PERIOD. THIS FRONT WILL DROP SOUTH THROUGH MONDAY IN RESPONSE TO A NORTHERN STREAM 500MB S/W TROUGH PUSHING SE OFF THE MID-ATLANTIC COAST. TWO QUESTIONS PERSIST ABOUT THIS FROPA...WILL IT PUSH ALL THE WAY THROUGH THE CWA...AND WILL IT BE ASSOCIATED WITH TSTMS. AS THE FRONT PUSHES SOUTH...IT WILL ENCOUNTER THE LEADING EDGE OF A STRONG UPPER RIDGE BUILDING EASTWARD FROM THE GREAT PLAINS. RIDGES TEND TO WIN THESE PLACEMENT BATTLES...BUT GUIDANCE CONTINUES TO INSIST THAT FROPA WILL TAKE PLACE THROUGH THE ENTIRE CWA. S/W DRIVING IT IS FAIRLY POTENT...AND RIDGE IS ONLY BEGINNING TO MOVE EAST...SO WILL CONTINUE TO SHOW FROPA THROUGH THE AREA MONDAY. AT THE SAME TIME...DECENT CONVERGENCE ALONG THE BOUNDARY INTO RICH THETA-E AIR SHOULD SUPPORT SOME SHOWERS AND ISOLATED TSTMS. BEST CHANCE LOOKS TO BE ACROSS SOUTHERN ZONES WHERE HEATING AND HIGHER PWATS WILL SUPPORT MORE PRECIP...BUT WEAK NVA AT 500MB AND CONFLUENCE AT JET LEVEL WILL INHIBIT MUCH IN THE WAY OF CONVECTION. AM COMFORTABLE WITH THE INHERITED SCHC OF TSTMS...BUT EXPECT VERY LIGHT PRECIP AS EVIDENCED BY HPC QPF OF ONLY A FEW HUNDREDTHS OF AN INCH. TEMPS MONDAY WILL BE TRICKY AS WELL...SINCE 850MB TEMPS WILL FALL THROUGH THE DAY AND THERE COULD BE QUITE A TEMP GRADIENT FROM SW TO NE. TEMPS ONLY IN THE UPPER 70S FAR NE COASTAL ZONES...RISING INTO THE UPPER 80S IN THE PEE DEE REGION OF SC. MINS RANGE FROM AROUND 50 FAR NE TO AROUND 60 IN THE SOUTH. WEAK CAA ON TUESDAY WILL KEEP TEMPS AROUND CLIMO UNDER PARTLY TO MOSTLY CLOUDY SKY CONDITIONS DUE TO MOISTURE TRAPPED BENEATH THE FRONTAL INVERSION. COLD FRONT SOUTH OF THE AREA TUESDAY WILL STALL AND WAVER BACK NORTH...WHILE INCREASING ISENTROPIC LIFT WILL SUPPORT INCREASING SHOWERS ACROSS SOUTHERN ZONES...BUT ONCE AGAIN WITH LIMITED QPF. MINS TUESDAY NIGHT STAY ABOVE 60 ACROSS MOST OF THE AREA AS HIGH PRESSURE DRIFTS OFFSHORE CREATING WARM SOUTHERLY FLOW AND CLOUD COVER. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY...MAIN FOCUS FOR THE EXTENDED REMAINS ON THE MID LEVEL SYSTEM NOW MOVING/DIGGING ACROSS THE WESTERN U.S. AND ITS MOVEMENT/EVOLUTION THROUGH LATE WEEK. HPC CONTINUES TO FAVOR THE ENSEMBLE MEAN OF THE ECMWF WHICH IS SLIGHTLY MORE AMPLIFIED AND SLOWER AND THE GFS MEAN. I HAVE MADE FEW ADJUSTMENTS IN POPS OTHER THAN TO DECREASE INCREMENTALLY VALUES FOR THURSDAY AS THE MID LEVEL RIDGE AMPLIFIES ACROSS THE AREA JUST BEFORE THE MAIN SYSTEM MOVES ACROSS EARLY FRIDAY. FOR WEDNESDAY A BACKDOOR FRONT CONTINUES TO WARRANT CHANCE POPS. SATURDAY AND SUNDAY REMAIN DRY FOR NOW. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...KLTX VWP IS MEASURING 40 KT WIND FROM THE WSW AS OF 05Z. WINDS JUST OFF THE DECK INCREASE RAPIDLY AND WILL INCLUDE WIND SHEAR IN THE FORECAST WITH THESE HIGHER WINDS MIXING OUT AROUND SUNRISE. CEILINGS AND VISIBILITIES ARE EXPECTED TO REMAIN IN THE VFR CATEGORY THROUGH THE TAF PERIOD. HOWEVER...THERE IS A RISK FOR AN IFR STRATUS LAYER TO DEVELOP THROUGH 09Z OR SO AT THE COAST. SW WINDS WILL SHIFT TO THE NORTH LATE MORNING AND THIS AFTERNOON FROM N TO S AS A COLD FRONT SINKS SOUTHWARD ACROSS THE TERMINALS. THERE MAY BE ISOLATED CONVECTION ALONG AND AHEAD OF THE FRONT...WITH THE RESULTANT ADDING ANOTHER BOUNDARY. HAVE DECIDED TO ADD VCSH TO THE TAFS...NOT CONFIDENT ENOUGH TO ADD A TEMPO AT THIS TIME. DEVELOPING GUSTY NORTH WINDS WILL CONTINUE THROUGH THE AFTERNOON...DIMINISHING DURING THE EVE AS THEY VEER TO THE NORTHEAST. EXTENDED OUTLOOK...LOW CONFIDENCE SHOWERS/ISOLATED THUNDERSTORMS MONDAY NIGHT AND TUESDAY. SCATTERED CONVECTION POSSIBLE WEDNESDAY WITH A BETTER CHANCE FOR PRECIP ON THURSDAY INTO EARLY FRIDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 PM SUNDAY...WINDS CONTINUE TO VEER TO THE SW LATE THIS EVENING AND HAVE INCREASED TO 10-15 KT. PROGGED BY HRRR AND NAM MODELS...SW-W WINDS WILL FURTHER INCREASE OVERNIGHT TO 15 TO 20 KT THRU THE PRE-DAWN HRS OF MONDAY. WIND DRIVEN WAVES WILL DOMINATE SIGNIFICANT SEAS WITH SEAS BUILDING TO 2 TO 4 FT ...EXCEPT 3 TO 5 FT ACROSS THE WATERS OFF CAPE FEAR SOUTH TO LITTLE RIVER INLET DUE TO THE LONGER SW-W FETCH. SCEC THRESHOLDS MAY BE MET FOR THE JUST THE AFOREMENTIONED WATERS AND WILL MONITOR FOR POSSIBLE ISSUANCE. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 300 PM SUNDAY...COLD FRONT CROSSES THE WATERS DURING MONDAY...TURNING WINDS FROM THE WEST AT 10-15 KTS EARLY...TO THE NE AT 10-15 KTS BY MONDAY NIGHT. THIS TRANSITION WILL OCCUR FIRST ACROSS THE NORTHERN WATERS...AND LATER IN THE DAY ACROSS THE SOUTH. WAVE SPECTRUM WILL CONSIST OF A LOW AMPLITUDE ESE 1FT/9SEC SWELL AND A BUILDING 3-4FT/5SEC NE WIND WAVE. THESE WILL COMBINE TO CREATE SEAS OF 2-3 FT...SLIGHTLY LOWER IN THE SHADOWED REGION SW OF FRYING PAN SHOALS. HIGH PRESSURE DRIFTS OFFSHORE TUESDAY ALLOWING WINDS TO SLOWLY VEER TO THE SOUTH AS RETURN FLOW SETS UP. SPEEDS OF ONLY AROUND 10 KTS WILL PRODUCE CONTINUED 2-3 FT SEAS...COMPRISED OF A ENE WIND CHOP EARLY...BECOMING A SW WIND CHOP LATE. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...EXPECT A SOUTHWEST FLOW INITIALLY AS BERMUDA HIGH PRESSURE PREVAILS AND A FRONT LURKS OFF TO THE NORTH WITH A PIEDMONT TROUGH AS WELL. THE FRONT MOVES ACROSS LATE WEDNESDAY INTO THURSDAY MORNING AS MOST IF NOT ALL WATERS WILL SEE NORTHEASTERLY WINDS BY 1200 UTC THURSDAY. UNCERTAINTY REMAINS FOR THE REMAINDER OF THE FORECAST AS SURFACE PRESSURE PATTERN SHOWS LOW PRESSURE DROPPING TO THE SOUTH AND WINDS TURNING TO THE EAST. GOOD THING IS THE STRENGTH OF THE LOW SHOULD REMAIN RELATIVELY WEAK SO DO NOT ANTICIPATE ANY HEADLINES. THE STRONGEST WINDS SHOULD OCCUR WEDNESDAY WITH 10-15 KNOTS. WAVEWATCH SEAS ARE REFLECTIVE OF THE WINDS AT LEAST INITIALLY. HAD TO SCALE BACK LATER IN THE PERIOD BUT OVERALL SEAS REMAIN BELOW FLAG CRITERIA AS WELL. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH SHORT TERM...JDW LONG TERM...SHK AVIATION...RJD/HDL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1254 PM CDT MON APR 2 2012 .DISCUSSION...MINOR UPDATES TO TEMPERATURES AND PRECIPITATION. ADJUSTED TEMPERATURES LOWER ONCE AGAIN...WITH HIGHS MAINLY IN THE UPPER 40S TO LOWER 50S. CLOUD DECK IS SLOW TO ERODE FROM THE WEST...THUS KEEPING TEMPERATURES DOWN. THE FAR WEST WILL LIKELY SEE SUNSHINE IN THE NEXT HOUR OR TWO AS THE CLOUD SHIELD MOVES SLOWLY EAST...THUS THE FAR WEST MAY SEE SOME MIDDLE 50S. LATEST HIGH RESOLUTION RUC LIFTS CURRENT CONVECTION NORTHWARD THROUGH THE AFTERNOON...AS THE ENTIRE SYSTEM TRACKS SLOWLY EAST. LOWERED POPS OVER THE FAR SOUTHEAST...KEEPING HIGHEST POPS FROM WESTERN MCINTOSH THROUGH STUTSMAN COUNTIES. ALSO MENTIONED SCATTERED SPRINKLES INTO THE EVENING OVER CENTRAL NORTH DAKOTA. THERE HAVE BEEN SOME SPRINKLES REACHING THE GROUND UNDER THE ELEVATED REFLECTIVITIES ACROSS THE WEST. && .AVIATION...TROUGH OF LOW PRESSURE EXTENDING NORTH THROUGH THE EASTERN DAKOTAS WILL CONTINUE TO RESULT IN EXTENSIVE VFR CLOUDINESS THROUGH THIS AFTERNOON ACROSS CENTRAL AND EASTERN PORTIONS OF NORTH DAKOTA. SHOULD SEE SKIES TRENDING TOWARDS SCT- SKC AFTER 21Z WEST...THEN SCT-SKC CENTRAL 02-05Z. -SHRA WILL END BY 20Z SOUTHWEST AND CENTRAL AROUND 00Z. LINE OF ENHANCED SHOWERS AND THUNDERSTORMS AND MVFR CIGS FROM KMBG TO KJMS WILL SLOWLY LIFT NORTH WITH TIME THIS AFTERNOON. WILL CONTINUE TO MENTION VCTS AT KJMS THROUGH 01Z. STRONG NORTH WINDS WITH GUSTS BETWEEN 30-40KTS EXPECTED AT KBIS AND KJMS THROUGH 23-00Z. && .BIS WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NDZ020- 034>037-042-045>048-050-051. WIND ADVISORY UNTIL 3 PM MDT THIS AFTERNOON FOR NDZ033-040-041- 043-044. && $$ SHORT TERM...TWH AVIATION...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
327 AM CDT MON APR 2 2012 .SHORT TERM...MAIN CHALLENGE WILL BE PRECIP/THUNDER CHANCES TODAY. 00Z MODELS INITIALIZED WITH MINIMAL ERRORS. GFS/ECMWF/GEM ALL AGREE WITH TIMING WITH NAM FASTER. WILL SIDE WITH THE SLOWER SOLUTIONS. UPPER TROUGH ACROSS THE ROCKIES WILL BE NEAR THE EASTERN FA BY 12Z TUESDAY. A COLD FRONT WILL SLOWLY PROPAGATE FROM WEST TO EAST THROUGH THE REGION. MODELS INDICATE WEAK TO MODERATE INSTABILITY (850MB CAPE AROUND 1000 J/KG) WILL ADVECT INTO THE SOUTHERN FA BY 12Z THIS MORNING...WITHIN WARM AIR ADVECTION REGIME. HRRR SUGGESTS THUNDER TO DEVELOP ACROSS AN AREA FROM SOUTHEAST NORTH DAKOTA INTO THE BEMIDJI AREA. DEEP LAYER SHEAR IS MARGINAL...BUT AN ISOLATED SEVERE HAIL REPORT IS POSSIBLE. THIS ACTIVITY DIMINISHES BY AFTERNOON AS 850MB FLOW WEAKENS. A BAND OF SHOWERS (MAYBE ISOLD THUNDER) WILL LIKELY DEVELOP ALONG AN 850MB BAROCLINIC ZONE BY NOON TO THE NORTH OF THE MORNING CONVECTIVE ACTIVITY (AROUND AN AREA FROM VALLEY CITY TO HALLOCK). FOLLOWING GFS/ECMWF/GEM 850MB FRONTOGENESIS...THIS BAND OF SHOWERS SHOULD GRADUALLY PROPAGATE TO THE EAST/SOUTHEAST INTO THE OVERNIGHT HOURS. TIMED 60 POPS ACCORDING TO THIS TIMING. THIS BAND OF FRONTOGENESIS WILL INTERACT WITH PWATS 0.75 TO 1.00 INCH. GIVEN THE ABOVE FACTORS THINKING AREAL QPF 0.50 INCH TO 1.00 INCH. WINDS WILL BECOME NORTH BEHIND THE COLD FRONT...AND CLOSE TO ADVISORY CRITERIA. GIVEN CURRENT MODEL 925MB WINDS SPEEDS OF 30-35 KNOTS...THINKING MOST AREAS WILL BE JUST BELOW ADVISORY CRITERIA. STRONGEST COLD AIR ADVECTION REMAINS WEST/SOUTH OF THE FA. MAX TEMPS SHOULD REMAIN IN THE 50S CONSIDERING CONSIDERABLE CLOUD COVER. RIDGING AFFECT THE REGION FOR THE REMAINDER OF THE PERIOD. THE AIRMASS WILL CHANGE LITTLE...AND CONDITIONS SHOULD BE SIMILAR EACH DAY. .LONG TERM (THURSDAY-SUNDAY)...MODELS IN GOOD AGREEMENT WITH THE EXTENDED TIME PERIOD AS 500MB RIDGING DOMINATES THE WEATHER PATTERN OVER THE NORTHERN PLAINS FROM THE MIDDLE TO THE END OF THE WEEK. AS THE RIDGING SHIFTS EAST SOUTHWESTERLY FLOW DEVELOPS AND WILL BRING AN INCREASE OF SHOWER ACTIVITY BEGINNING FRIDAY AFTERNOON. BEST CHC FOR PCPN WILL BE SATURDAY ASSOCIATED WITH FROPA. TEMPS FOR THE PERIOD TO BE ABOVE NORMAL... WITH COOLER TEMPS EXPECTED THIS NEXT WEEKEND AS CLOUDS INCREASE WITH CHC POPS. && .AVIATION...MVFR CIGS EXPECTED TO DEVELOP THIS MORNING ALONG AND EAST OF THE VALLEY. THESE CIGS WILL LIKELY LOWER INTO IFR RANGE BY AFTERNOON. SCATTERED TSRA EXPECTED TO DEVELOP ALONG A LINE FROM FARGO TO BEMIDJI AROUND SUNRISE. THIS ACTIVITY SHOULD DIMINISH BY NOON...BUT A BAND OF SHOWERS WILL LIKELY DEVELOP FROM VALLEY CITY TO THE NORTHEAST...AND THEN GRADUALLY MOVE EAST THROUGH THE DAY. CIGS WILL REMAIN LOW INTO TONIGHT...CLEARING FROM WEST TO EAST. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG/JK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
927 PM EDT TUE APR 3 2012 .SYNOPSIS... LOW PRESSURE WILL MOVE THROUGH THE REGION TONIGHT...WITH THUNDERSTORMS DEVELOPING UNTIL TOMORROW MORNING. HIGH PRESSURE WILL GRADUALLY MOVE IN FROM THE NORTH THROUGH THE END OF THE WEEK...WITH GRADUALLY COOLING TEMPERATURES. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AIRMASS ACROSS OUR AREA REMAINS JUST SLIGHTLY UNSTABLE AND THIS IS GENERALLY ALOFT AS BOUNDARY LAYER HAS COOLED/DRIED IN THE WAKE OF EARLIER OUTFLOW BOUNDARY. A LINE OF SHOWERS AND THUNDERSTORMS IS CONTINUING ALONG THE COLD FRONT BACK ACROSS CENTRAL ILLINOIS INTO NORTHERN INDIANA...BUT SO FAR THESE HAVE HAD A TOUGH TIME PROGRESSING EASTWARD. THE LATEST HRRR IS SHOWING THIS PCPN PUSHING EAST INTO OUR NORTHERN AREAS THROUGH 06Z...BUT GIVEN TRENDS AND MORE STABLE AIRMASS ACROSS OUR AREA...NOT SURE IF THAT WILL PAN OUT. AS LOW OVER MISSOURI PUSHES EAST THROUGH THE OVERNIGHT HOURS...WE SHOULD BEGIN TO MOISTEN UP A BIT MORE AND PERHAPS DESTABILIZE ALOFT A LITTLE BETTER. WILL MAKE SOME DOWNWARD ADJUSTMENTS TO POPS IN THE NEAR TERM AND BRING BETTER POPS IN FROM THE SOUTHWEST LATER TONIGHT. SEVER THREAT SEEMS TO BE RATHER LOW GIVEN BOTH WEAK SHEAR PROFILES AND WEAK INSTABILITY. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... THE SOUTHERN HALF OF THE CWA WILL START THE DAY WEDNESDAY IN A FAVORABLE CONVERGENT AREA FOR CONTINUED SHOWER AND THUNDERSTORM DEVELOPMENT. THIS WILL DIMINISH AS THE SURFACE FRONT PUSHES SOUTH OF THE FORECAST AREA DURING THE AFTERNOON...BEGINNING A PATTERN OF NORTH WINDS AND COLD ADVECTION THAT WILL GO THROUGH THE END OF THE WEEK. MOISTURE WILL REMAIN JUST SOUTH OF THE FORECAST AREA...AND MAY ACTUALLY EDGE NORTH ENOUGH TO PRODUCE SOME PRECIPITATION IN THE FAR SOUTH ON THURSDAY. THIS WILL BE POSSIBLE AS A WEAKENING CLOSED UPPER LOW MOVES EAST INTO THE TENNESSEE VALLEY. OVERALL...HOWEVER...A DRIER AND COOLER AIR MASS WILL BE THE RESULT OF THIS SHIFT IN THE WEATHER PATTERN. TEMPERATURES...THUS...SHOULD COOL THROUGH THE FORECAST PERIOD. THIS WILL RESULT IN MIN TEMPERATURES GETTING VERY CLOSE TO FREEZING ON THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... BEGINNING OF PERIOD WILL BE MARKED BY AN AMPLIFIED UPPER LEVEL FLOW PATTERN. UPPER LOW THAT HAD BEEN TREKKING ACROSS THE MID SOUTH WILL BE ABSORBED INTO AN EAST COAST TROUGH. SHARP RIDGING OVER THE PLAINS WILL PLACE THE LOCAL AREA IN NORTHERLY FLOW ALOFT. AT THE SFC...HIGH PRESSURE WILL BUILD SOUTHWARD FROM ONTARIO INTO THE GREAT LAKES. THIS WILL LEAD TO DRY AND SEASONABLE CONDITIONS FOR FRIDAY. ON FRIDAY NIGHT...THE SFC HIGH WILL BUILD OVERHEAD...LEADING TO CLEAR SKIES AND LIGHT WINDS. FROST WILL BE A CONCERN OVER MUCH OF THE CWA EXCEPT PERHAPS NORTHERN KY...AND THE TYPICAL COOLER LOCALES EAST OF COLUMBUS MAY APPROACH FREEZING (THESE TEMPERATURES REPRESENT A DOWNWARD ADJUSTMENT FROM THE PREVIOUS FORECAST). AS THE HIGH SLIDES EAST OF THE AREA ON SATURDAY...WINDS WILL BECOME SOUTHERLY AND PROMOTE TEMPERATURES TO RISE A LITTLE ABOVE NORMAL. THE NEXT SHORT WAVE TROUGH TO APPROACH FROM THE ROCKIES WILL MAINLY SERVE TO SQUASH THE UPPER RIDGE...WITH MOST OF THE ENERGY REMAINING NORTH OF THE AREA. A SFC LOW WILL TRACK WELL NORTH INTO CANADA...WITH A TRAILING COLD FRONT CROSSING THE AREA ON SUNDAY. MODELS DISAGREE A LITTLE ON TIMING...BUT APPEARS TO BE MAINLY A DAYTIME EVENT...SO DELAYED POPS A LITTLE FROM PREVIOUS FORECAST. IN WESTERLY FLOW THROUGHOUT THE ATMOSPHERE...THE FRONT WILL BE MOISTURE STARVED...SO MAINTAINED THE LOW CHANCE POPS. INSTBY WILL BE WEAK BUT PRESENT (MORESO SOUTH)...SO KEPT THUNDER MENTION. AIRMASS CHANGE BEHIND THE FRONT WILL BE MINIMAL AS WEAK SFC RIDING EXTENDS INTO THE AREA BY SUNDAY NIGHT INTO EARLY MONDAY...WITH TEMPERATURES REMAINING SLIGHTLY ABOVE NORMAL. AS UPPER LEVEL GYRE FORMS OVER EASTERN CANADA...ANOTHER SHORTWAVE TROUGH WILL ROTATE DOWN THROUGH THE AREA LATE MONDAY INTO TUESDAY. THIS SYSTEMS WILL BE MOISTURE STARVED AS WELL...SO LIMITED FORECAST TO CHANCE POPS. LEFT THUNDER MENTION OUT WITH LIMITED INSTBY AND HIGHER THETA-E SUPPRESSED FAR TO OUR SOUTH. WHILE MODELS DIFFER WITH TIMING AND EXACT FEATURES...THEY AGREE ON THE MORE SUBSTANTIAL EFFECT FROM THIS SYSTEM...WHICH WILL BE THE COLDER AIR IT PULLS SOUTHWARD INTO THE AREA. FORECAST HIGH TEMPERATURES ON TUESDAY ARE ABOUT 10 DEGREES BELOW NORMAL. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... OUTFLOW FROM EARLIER CONVECTION THAT MOVED ACROSS CENTRAL OHIO IS CONTINUING TO PUSH SOUTHWEST ACROSS MUCH OF OUR AREA. THIS HAS HELPED STABILIZE US IN THE SHORT TERM OVER ALL BUT OUR FAR SOUTHWEST. AS A RESULT...EXPECT MAINLY JUST SOME CIRRUS ACROSS THE AREA THROUGH THIS EVENING. MEANWHILE...SCATTERED THUNDERSTORMS HAVE DEVELOPED ACROSS CENTRAL ILLINOIS ALONG A COLD FRONT THAT STRETCHES ACROSS NORTHERN INDIANA INTO NORTHERN OHIO. THIS COLD FRONT IS FORECAST TO SAG SLOWLY SOUTH THROUGH THE OVERNIGHT HOURS AND INTO WEDNESDAY MORNING. MODELS CONTINUE TO INDICATE THAT WESTERLY LOW LEVEL FLOW AHEAD OF THE FRONT WILL BE ABLE TO ADVECT SOME BETTER INSTABILITIES INTO OUR AREA THROUGH THE OVERNIGHT HOURS. THIS WOULD LIKELY ALLOW FOR THE THUNDERSTORM ACTIVITY TO EXPAND EASTWARD ALONG THE FRONT AND INTO OUR AREA THROUGH THE OVERNIGHT HOURS. WITH THE SOUTHWARD PUSH OF THE FRONT...EXPECT THE BEST CHANCE FOR PCPN/THUNDER TO BE ACROSS OUR SOUTHWEST FA...WITH CHANCES DECREASING HEADING TO THE NORTH/EAST. WILL THEREFORE HIT KCVG/KLUK THE HARDEST WITH PCPN FOR LATE TONIGHT INTO WEDNESDAY MORNING. PCPN SHOULD TAPER OFF ACROSS THE SOUTH THROUGH LATE MORNING...BUT GOOD CAA ON THE BACKSIDE OF THE FRONT COULD LEAD TO A PERIOD OF SOME MVFR CIGS...BEFORE SOME DRIER AIR IS ABLE TO WORK IN FROM THE NORTH LATE IN THE TAF PERIOD. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...JGL SHORT TERM...HATZOS LONG TERM...SNYDER AVIATION...JGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
126 AM EDT MON APR 2 2012 .SYNOPSIS... A COOLER AND DRIER AIR MASS ASSOCIATED WITH HIGH PRESSURE CENTERED OVER HUDSON BAY WILL BE DIRECTED INTO THE AREA TODAY BEHIND NORTHERLY WINDS...WHICH WILL BE RATHER GUSTY OVER THE EASTERN HALF OF THE STATE. THE NEXT CHANCE OF RAIN WILL COME BY LATE TUESDAY INTO EARLY WEDNESDAY...AS A WEAK AREA OF LOW PRESSURE MOVES EASTWARD FROM THE OHIO VALLEY ACROSS THE NORTHERN MID-ATLANTIC STATES. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... CLIPPER LOW OVER SOUTHERN PA LATE THIS EVENING WILL CONTINUE TO TRACK SE...PASSING OFF THE DELMARVA LATER TONIGHT. REGIONAL RADAR MOSAIC SHOWING RAIN STILL FALLING ACROSS THE SOUTHERN THIRD OF PA AT 03Z. HRRR AND RUC BOTH INDICATE THE LAST THE RAIN WILL EXIT SOUTHERN PA BTWN 05Z-06Z. CLEARING SKIES SHOULD DEVELOP LATE TONIGHT ACROSS CENTRAL AND SOUTHERN PA...AS MUCH DRIER AIR MASS OVERSPREADS THE STATE. LOW LVL MOISTURE TRAPPED BENEATH SUBSIDENCE INVERSION WILL LIKELY KEEP STRATO-CU LOCKED IN OVR THE N MTNS...WHILE DOWNSLOPING NORTHERLY FLOW YIELDS MCLEAR SKIES SOUTH OF I-80 BY DAWN. LIGHT WINDS WILL BECOME GUSTY FROM THE NW OVR THE ENTIRE REGION TONIGHT...AS CLIPPER LOW INTENSIFIES OFF THE E COAST. THESE GUSTY WINDS HAVE ALREADY DEVELOPED ACROSS THE NW MTNS AS OF 03Z AND BUFKIT SOUNDINGS SUPPORT GUSTS TO ARND 20KTS LATER TONIGHT ACROSS MUCH OF SOUTHERN PA. POST-FRONTAL AIR MASS WILL BE ONLY SEASONABLY COOL AND AN ACTIVE NW WIND WILL KEEP ATMOS MIXED OVERNIGHT...SO LOW TEMPS SHOULD ACTUALLY BE A BIT ABV SEASONAL NORMS...RANGING FROM THE L30S NW MTNS...TO ARND 40F SOUTH. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... MONDAY WILL BE BREEZY...DRIER AND A LITTLE COOLER AS NORTHERLY WINDS SPREAD IN BEHIND THE DEPARTING FRONT AND THE HIGH TO OUR NORTH BEGINS NOSING DOWN. ANY EARLY CLOUDS WILL YIELD TO PLENTY OF SUNSHINE BY MID TO LATE MORNING. GEFS 850 TEMPS SUPPORT HIGH TEMPS IN THE 50S. DESPITE THE DRY AIR AND GUSTY WINDS OVR EASTERN PA ON MONDAY...THINKING IS TODAY/S RAINFALL WILL DAMPEN FINE FUELS ENOUGH TO PRECLUDE A SIGNIFICANT WILDFIRE THREAT. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... BROAD UPPER TROFFING ALONG THE APPALACHIANS AT THE START OF THE PERIOD...AN EXTENSION OF A LARGE UPPER VORTEX OVER ERN CANADA...IS FORECAST TO WEAKEN AS THE MAIN SHORT WAVE TROF SWINGS OFFSHORE...ALLOWING HEIGHTS TO RISE TEMPORARILY ACROSS PA AND INTO NEW ENGLAND. TROFFING WILL RETURN MIDWEEK AS ENERGY IN THE ACTIVE NRN STREAM JET DROPS DOWN THE EAST SIDE OF THE UPPER RIDGE OVER THE CENTRAL U.S. THIS CENTRAL U.S. UPPER RIDGE/OMEGA BLOCK PATTERN WILL MAKE ONLY SLOW PROGRESS EAST AS IT IS BOMBARDED BY NUMEROUS NRN AND SRN STREAM WAVES AS WELL AS BEING IMPEDED BY THE ERN CANADA UPPER LOW. THIS WILL SERVE TO KEEP PA IN SOME DEGREE OF NW FLOW THROUGH THE REMAINDER OF THE LONG TERM PD. WHILE THIS WILL HELP SUPPORT THE DRY FORECAST...ANY WAVES IN THE FLOW COULD BECOME FLIES IN THE OINTMENT SO TO SPEAK. THOUGH AT THIS POINT NO OPPORTUNITIES FOR SIGNIFICANT RAINFALL APPEAR LIKELY. THE NW FLOW WILL ALSO BRING COOLER...OR RATHER CLOSE TO NORMAL...OR EVER SO SLIGHTLY BELOW NORMAL TEMPS FOR THUR AND FRI BEFORE A WARM UP FOR NEXT WEEKEND. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... WEAK FRONTAL SYSTEM AND WAVE OF LOW PRES CURRENTLY PUSHING SOUTH OF THE PA/MD LINE AS OF 05Z. COSPA DATA DEPICTS SHOWERS EXITING SRN PA BY 06Z. IR SATL SHOWS LOW CLOUDS MOVG SWD FROM NY COVERING MUCH OF CENTRAL PA WITH CIGS GENERALLY IN THE MVFR CATG BTWN 1500-3000KFT AGL...WITH LCL CIGS BLW 1KFT AGL ACRS PTNS OF THE ALLEGHENIES/LAUREL HIGHLANDS. THE REMAINDER OF THE PRE-DAWN HOURS WILL BE CLOUDY WITH MAINLY MVFR CIGS AND PATCHY DZ...AS MSTR PROFILES DRY OUT RAPIDLY ALOFT. A DRIER NLY FLOW ASSOC WITH CANADIAN HIGH PRES SHOULD BRING CLEARING TO THE NRN TIER BTWN 10-11Z AND 11-13Z IN THE CNTRL AIRFIELDS BASED ON LINEAR EXTRAPOLATION OF BACK EDGE OF LOW CLOUD DECK CROSSING LAKE ONTARIO. EXPECT DECREASING CLOUDS EARLY THIS MORNING SHORTLY AFT SUNRISE WITH CLR SKIES AND WDSPRD VFR BY MID- DAY. ANTICIPATE THE NLY WINDS TO INCREASE FROM MID MORNING THROUGH THE AFTN ESPECIALLY OVR ERN SXNS WITH GUSTS BTWN 25-30KTS. WINDS WILL SUBSIDE AFTER DARK AS HIGH PRES BUILDS OVER PA. OUTLOOK... TUE...VFR/MVFR WITH SHOWERS LATE. WED...MVFR WITH A CHC OF SHOWERS EARLY...OTHERWISE VFR. THU-FRI...VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/STEINBUGL NEAR TERM...FITZGERALD SHORT TERM...FITZGERALD/LA CORTE LONG TERM...LAMBERT/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1133 AM CDT MON APR 2 2012 .DISCUSSION.../ISSUED AT 1133 AM CDT/ SLOW MOVING COLD FRONT ACROSS OUR FAR WESTERN ZONES IS NEARLY STATIONARY THIS MORNING AND THE SURFACE LOW BUILDS NORTHWARD OVER THE CWA. EXPECT THIS FRONT TO REMAIN NEARLY STATIONARY INTO THE EARLY AFTERNOON BEFORE FINALLY TRACKING EASTWARD MID AFTERNOON INTO THE LATE EVENING. MEANWHILE STRATUS HAS FINALLY BEGUN TO RAPIDLY ERODE ACROSS OUR NORTHEASTERN THIRD. TEMPERATURES RAPIDLY JUMPING IN THE CLEAR AREA BETWEEN THESE STRATUS FIELDS WITH TEMPERATURES ALREADY IN THE UPPER 70S INTO OUR EXTREME SOUTHEASTERN ZONES. UPDATED TEMPERATURES ACROSS NW IA AND INTO THE I29 CORRIDOR WHERE SKIES WILL REMAIN PREDOMINATELY CLEAR INTO THE AFTERNOON AND THETA E ADVECTION IS PRETTY STRONG. COULD SEE ANOTHER DAY WELL INTO THE 80S IN PARTS OF THIS AREA. ALSO UPDATED TO SLOW DOWN THE DEVELOPMENT OF THE ISOLATED SHOWERS/SPRINKLES WITH THE SLOWER FRONTAL PROGRESSION. AHEAD OF THE FRONT...STRONG CAP LOOKS TO DOMINATE OUR EASTERN HALF WHICH WILL MAKE THUNDERSTORM DEVELOPMENT PROBLEMATIC THROUGH AT LEAST LATE THIS AFTERNOON. STILL...CANNOT RULE OUT SOME ISOLATED ELEVATED THUNDERSTORM DEVELOPMENT IN THE LATE AFTERNOON AND EARLY EVENING ACROSS OUR FAR EASTERN AREAS. WITH GOOD INSTABILITY...ENHANCEMENT OF THE LOW LEVEL JET AND GOOD MID LEVEL LAPSE RATES A FEW MARGINALLY SEVERE STORMS ARE A POSSIBILITY IF DEVELOPMENT DOES OCCUR. && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ IFR/MVFR STRATUS AND AREAS OF FOG ACROSS THE EASTERN AND NORTH CENTRAL ZONES QUICKLY LIFTING LATE THIS MORNING. VISIBILITY AND CEILINGS WILL IMPROVE TO VFR FROM WEST TO EAST IN THIS AREA INTO THE EARLY AFTERNOON. MEANWHILE A SLOW MOVING FRONT ACROSS CENTRAL SOUTH DAKOTA WILL GRADUALLY TRACK EASTWARD ACROSS THE FORECAST AREA THROUGH THE LATE EVENING. STRATUS WILL FOLLOW BEHIND THIS FRONT ALONG WITH A SMALL POTENTIAL FOR LIGHT RAIN SHOWERS OR SPRINKLES. WINDS WILL FLIP TO THE NORTH NORTHWEST BEHIND THE FRONT AND BECOME QUITE STRONG THIS AFTERNOON AND EVENING...AROUND 25 TO 35 KT WITH POSSIBLY A FEW GUSTS AROUND 40 KT IN THE JAMES VALLEY AND WESTWARD. ELSEWHERE...WINDS WILL BECOME BREEZY BEHIND THE FRONT THIS EVENING AND OVERNIGHT. THERE IS A SMALL POTENTIAL FOR SOME THUNDERSTORM DEVELOPMENT THIS EVENING ACROSS PARTS OF NORTHWEST IOWA TOWARDS SOUTH CENTRAL MINNESOTA. && .PREV DISCUSSION.../ISSUED AT 500 AM CDT/ CURRENTLY SEEING A COLD FRONT PUSHING INTO OUR WESTERN CWA...HAVING JUST PUSHED THROUGH CHAMBERLAIN...AND A WARM FRONT DRAPED FROM EAST OF HURON SOUTH ACROSS SIOUX FALLS INTO NORTHWEST IOWA. EXPECTATION IS THAT THIS WARM FRONT WILL CONTINUE TO SLOWLY DRIFT SOUTHWEST...WITH THE AREA OF LOW STRATUS ACCOMPANYING IT. GUIDANCE CONTINUES TO SLOW DOWN THE PROGRESSION OF THE COLD FRONT. MODELS COMING INTO AGREEMENT THAT IT WILL WILL SLOWLY PUSH EAST THROUGH THE DAY...NOT PASSING THROUGH SIOUX FALLS UNTIL 20-22Z...AND THE EASTERN EDGE OF THE CWA 2-4Z. THIS WILL IMPACT TODAYS TEMPERATURE AND WIND POTENTIAL. TEMPERATURES ARE A BIG QUESTION MARK WITH A LARGE SPREAD IN THE GUIDANCE TODAY. WITH THE SLOWER ARRIVAL OF THE COLD FRONT...RAISED TEMPERATURES SEVERAL DEGREES IN THE WEST. MEANWHILE...FROM SIOUX FALLS TO SIOUX CITY AND POINTS EAST...TEMPERATURES DEPEND ON PROGRESSION OF THE WARM FRONT AND ATTENDANT LOW CLOUDS. THE HRRR HAS PERFORMED FAIRLY WELL THE PAST COUPLE DAYS WITH THE EVOLUTION OF THE WARM FRONT AND CLOUDS. IT LIFTS THE FRONT NORTH ALMOST THROUGH THE ENTIRE CWA...RESULTING IN HIGHS IN THE 80S FROM YANKTON TO SIOUX FALLS AND POINTS EAST...WITH NEAR 90 ONCE AGAIN IN SIOUX CITY. THIS IS THE WARMEST MODEL SOLUTION...BUT THE NAM AND ECMWF ARE ONLY A FEW DEGREES COOLER. THE LOW LEVEL MOISTURE AND STRATUS WILL BE A BIT DEEPER THIS MORNING COMPARED TO LAST...SO THINK IT MAY TAKE A BIT LONGER FOR CLOUDS TO ERODE. BUT GIVEN WHAT HAS HAPPENED THE PAST FEW DAYS...THE SLOWER COLD FRONT...AND MODEL AGREEMENT...CURRENT THINKING IS THAT THEY DO INDEED ERODE...ALLOWING FOR ANOTHER VERY WARM DAY WITH HIGHS IN THE UPPER 70S TO MID 80S ACROSS EXTREME SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA. GIVEN UNCERTAINTY...DID NOT GO QUITE AS WARM AS WARMEST SOLUTIONS...BUT WOULD NOT BE SURPRISED IF TEMPS END UP A FEW DEGREES WARMER THAN CURRENT FORECAST. ON THE OTHER HAND...IF THE LOW CLOUDS STAY LOCKED IN TEMPERATURES WILL BE MUCH COOLER THAN FORECAST...ALTHOUGH SEE THIS AS A LOWER PROBABILITY EVENT AT THIS TIME. NEXT UP IS THE WINDS. WINDS WILL BECOME STRONG BEHIND THE COLD FRONT. 900MB WINDS ARE EXPECTED TO BE IN THE 30 TO 40 KTS RANGE. THE COMBINATION OF DECENT LOW LEVEL CAA AND PRESSURE RISES WILL HELP PROMOTE MIXING AND THE TRANSFER OF THESE WINDS TO THE SURFACE. A BORDERLINE WIND ADVISORY EVENT...BUT WILL KEEP THE CURRENT ADVISORY MAINLY AS IS...WITH SUSTAINED WINDS APPROACHING 30 MPH FOR A PERIOD IN THE WEST...WITH A FEW GUSTS AROUND 40 MPH. DID CUT ONE ROW OF COUNTIES OFF THE ADVISORY GIVEN THE SLOWER MOVEMENT OF THE FRONT AND A SLIGHTLY WEAKER CORE OF LOW LEVEL WINDS. PRECIP CHANCES LOOK TO BE CLOSE TO ZERO OUT AHEAD OF THE FRONT. SOME ELEVATED CAPE IN OUR FAR NORTHWEST...BUT A STRONG CAPPING INVERSION AROUND 750MB WILL PREVENT ANY ELEVATED CONVECTION. DEEP LOW LEVEL MOISTURE BEHIND THE FRONT WILL ALLOW FOR DRIZZLE AND LIGHT SHOWERS...MAINLY NORTH OF INTERSTATE 90 AND WEST OF INTERSTATE 29. EXPECT THIS AREA OF DRIZZLE TO BEGIN TO DISSIPATE TONIGHT AS THE MOISTURE LAYER BECOMES SHALLOW AND BEGINS TO ERODE AWAY FROM WEST TO EAST. NAM AND GFS BOTH SHOWING DECENT ELEVATED CAPE BEHIND THE COLD FRONT FROM PARCELS UP AROUND 750MB. IT LOOKS LIKE WE SHOULD REMAIN CAPPED...HOWEVER STRONG LOW LEVEL LIFT GENERATED BY THE DEVELOPING LOW PRESSURE AND THETAE ADVECTION MAY ATTEMPT TO BREAK THIS CAP. AND WITH MOISTURE UP TO 750MB...NOT OUT OF THE QUESTION THAT THOSE PARCELS GO AND WE GET A THUNDERSTORM. BEST CHANCE OF THIS APPEARS TO BE ACROSS SOUTHWEST MINNESOTA BETWEEN 0Z AND 6Z...WHERE THE LIFT IS STRONGEST AND MOISTURE DEEPEST. OTHER CONCERN IS ACROSS NORTHWEST IOWA. WITH THE VERY WARM TEMPERATURES WILL LIKELY SEE CAPES AROUND 2000 J/KG THIS AFTERNOON. HOWEVER EXPECT THE STRONG MID LEVEL CAP TO HOLD. IF WE GET HOTTER THAN FORECAST THE DEEPER MIXING SHOULD RESULT IN LOWER DEWPOINTS...WITH THE NET RESULT OF BEING CAPPED STAYING THE SAME. THIS IS SUPPORTED BY THE NAM AND HRRR. SHORTWAVE RIDGING SHOULD PROVIDE A DRY DAY TUESDAY. OUR NEXT WEATHER FEATURE IS A CUT OFF LOW ACROSS THE SOUTHERN PLAINS. NAM...GFS AND ECMWF HAVE SIMILAR TRACKS OF THE UPPER LEVEL LOW ACROSS KANSAS. THIS SHOULD PUT AT LEAST OUR SOUTHERN CWA IN DECENT QG FORCING LATE TUESDAY NIGHT INTO WEDNESDAY. MODELS DIVERGE ON HOW THEY HANDLE MOISTURE ADVECTION INTO THE AREA. WITH STRONGER SHORTWAVE RIDGING AND HIGH PRESSURE TO THE NORTH...ECMWF AND SREF KEEP THE DEEPER MOISTURE AND PRECIP TO OUR SOUTH...WHILE THE GFS AND NAM PUSH IT UP TO INTERSTATE 90 ON WEDNESDAY. GIVEN MODEL UNCERTAINTY WILL BLEND THE TWO SOLUTIONS...TRENDING A BIT CLOSER TO THE ECMWF AND SREF SOLUTIONS. THURSDAY AND MOST OF FRIDAY SHOULD REMAIN DRY WITH AN UPPER LEVEL RIDGE OVERHEAD. ANOTHER SHORTWAVE WILL PUSH ACROSS LATER FRIDAY INTO SATURDAY BRINGING OUR NEXT CHANCE OF SHOWERS AND POSSIBLY A THUNDERSTORM. HIGH TEMPERATURES TUESDAY THROUGH SUNDAY LOOK GENERALLY IN THE UPPER 50S TO LOWER 60S...WITH MODELS IN FAIRLY GOOD AGREEMENT WITH THESE VALUES. LOW TEMPERATURES SHOULD BE IN THE UPPER 30S TO LOWER 40S. DEPENDING ON WHAT EXACTLY HAPPENS WITH THE UPPER LOW ON WEDNESDAY...TEMPERATURES MAY NEED TO BE ADJUSTED UP A FEW DEGREES IF THE SOUTHERN SOLUTION PANS OUT...OR DOWN IF THE SHOWERS ARE MORE WIDESPREAD. /CHENARD && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...WIND ADVISORY FROM 10 AM TO 9 PM CDT MONDAY FOR SDZ038-039- 052>054-058>061-064>066-068-069. WIND ADVISORY FROM 7 AM TO 9 PM CDT MONDAY FOR SDZ050-057-063. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
636 AM CDT MON APR 2 2012 .DISCUSSION.../ISSUED AT 500 AM CDT/ CURRENTLY SEEING A COLD FRONT PUSHING INTO OUR WESTERN CWA...HAVING JUST PUSHED THROUGH CHAMBERLAIN...AND A WARM FRONT DRAPED FROM EAST OF HURON SOUTH ACROSS SIOUX FALLS INTO NORTHWEST IOWA. EXPECTATION IS THAT THIS WARM FRONT WILL CONTINUE TO SLOWLY DRIFT SOUTHWEST...WITH THE AREA OF LOW STRATUS ACCOMPANYING IT. GUIDANCE CONTINUES TO SLOW DOWN THE PROGRESSION OF THE COLD FRONT. MODELS COMING INTO AGREEMENT THAT IT WILL WILL SLOWLY PUSH EAST THROUGH THE DAY...NOT PASSING THROUGH SIOUX FALLS UNTIL 20-22Z...AND THE EASTERN EDGE OF THE CWA 2-4Z. THIS WILL IMPACT TODAYS TEMPERATURE AND WIND POTENTIAL. TEMPERATURES ARE A BIG QUESTION MARK WITH A LARGE SPREAD IN THE GUIDANCE TODAY. WITH THE SLOWER ARRIVAL OF THE COLD FRONT...RAISED TEMPERATURES SEVERAL DEGREES IN THE WEST. MEANWHILE...FROM SIOUX FALLS TO SIOUX CITY AND POINTS EAST...TEMPERATURES DEPEND ON PROGRESSION OF THE WARM FRONT AND ATTENDANT LOW CLOUDS. THE HRRR HAS PERFORMED FAIRLY WELL THE PAST COUPLE DAYS WITH THE EVOLUTION OF THE WARM FRONT AND CLOUDS. IT LIFTS THE FRONT NORTH ALMOST THROUGH THE ENTIRE CWA...RESULTING IN HIGHS IN THE 80S FROM YANKTON TO SIOUX FALLS AND POINTS EAST...WITH NEAR 90 ONCE AGAIN IN SIOUX CITY. THIS IS THE WARMEST MODEL SOLUTION...BUT THE NAM AND ECMWF ARE ONLY A FEW DEGREES COOLER. THE LOW LEVEL MOISTURE AND STRATUS WILL BE A BIT DEEPER THIS MORNING COMPARED TO LAST...SO THINK IT MAY TAKE A BIT LONGER FOR CLOUDS TO ERODE. BUT GIVEN WHAT HAS HAPPENED THE PAST FEW DAYS...THE SLOWER COLD FRONT...AND MODEL AGREEMENT...CURRENT THINKING IS THAT THEY DO INDEED ERODE...ALLOWING FOR ANOTHER VERY WARM DAY WITH HIGHS IN THE UPPER 70S TO MID 80S ACROSS EXTREME SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA. GIVEN UNCERTAINTY...DID NOT GO QUITE AS WARM AS WARMEST SOLUTIONS...BUT WOULD NOT BE SURPRISED IF TEMPS END UP A FEW DEGREES WARMER THAN CURRENT FORECAST. ON THE OTHER HAND...IF THE LOW CLOUDS STAY LOCKED IN TEMPERATURES WILL BE MUCH COOLER THAN FORECAST...ALTHOUGH SEE THIS AS A LOWER PROBABILITY EVENT AT THIS TIME. NEXT UP IS THE WINDS. WINDS WILL BECOME STRONG BEHIND THE COLD FRONT. 900MB WINDS ARE EXPECTED TO BE IN THE 30 TO 40 KTS RANGE. THE COMBINATION OF DECENT LOW LEVEL CAA AND PRESSURE RISES WILL HELP PROMOTE MIXING AND THE TRANSFER OF THESE WINDS TO THE SURFACE. A BORDERLINE WIND ADVISORY EVENT...BUT WILL KEEP THE CURRENT ADVISORY MAINLY AS IS...WITH SUSTAINED WINDS APPROACHING 30 MPH FOR A PERIOD IN THE WEST...WITH A FEW GUSTS AROUND 40 MPH. DID CUT ONE ROW OF COUNTIES OFF THE ADVISORY GIVEN THE SLOWER MOVEMENT OF THE FRONT AND A SLIGHTLY WEAKER CORE OF LOW LEVEL WINDS. PRECIP CHANCES LOOK TO BE CLOSE TO ZERO OUT AHEAD OF THE FRONT. SOME ELEVATED CAPE IN OUR FAR NORTHWEST...BUT A STRONG CAPPING INVERSION AROUND 750MB WILL PREVENT ANY ELEVATED CONVECTION. DEEP LOW LEVEL MOISTURE BEHIND THE FRONT WILL ALLOW FOR DRIZZLE AND LIGHT SHOWERS...MAINLY NORTH OF INTERSTATE 90 AND WEST OF INTERSTATE 29. EXPECT THIS AREA OF DRIZZLE TO BEGIN TO DISSIPATE TONIGHT AS THE MOISTURE LAYER BECOMES SHALLOW AND BEGINS TO ERODE AWAY FROM WEST TO EAST. NAM AND GFS BOTH SHOWING DECENT ELEVATED CAPE BEHIND THE COLD FRONT FROM PARCELS UP AROUND 750MB. IT LOOKS LIKE WE SHOULD REMAIN CAPPED...HOWEVER STRONG LOW LEVEL LIFT GENERATED BY THE DEVELOPING LOW PRESSURE AND THETAE ADVECTION MAY ATTEMPT TO BREAK THIS CAP. AND WITH MOISTURE UP TO 750MB...NOT OUT OF THE QUESTION THAT THOSE PARCELS GO AND WE GET A THUNDERSTORM. BEST CHANCE OF THIS APPEARS TO BE ACROSS SOUTHWEST MINNESOTA BETWEEN 0Z AND 6Z...WHERE THE LIFT IS STRONGEST AND MOISTURE DEEPEST. OTHER CONCERN IS ACROSS NORTHWEST IOWA. WITH THE VERY WARM TEMPERATURES WILL LIKELY SEE CAPES AROUND 2000 J/KG THIS AFTERNOON. HOWEVER EXPECT THE STRONG MID LEVEL CAP TO HOLD. IF WE GET HOTTER THAN FORECAST THE DEEPER MIXING SHOULD RESULT IN LOWER DEWPOINTS...WITH THE NET RESULT OF BEING CAPPED STAYING THE SAME. THIS IS SUPPORTED BY THE NAM AND HRRR. SHORTWAVE RIDGING SHOULD PROVIDE A DRY DAY TUESDAY. OUR NEXT WEATHER FEATURE IS A CUT OFF LOW ACROSS THE SOUTHERN PLAINS. NAM...GFS AND ECMWF HAVE SIMILAR TRACKS OF THE UPPER LEVEL LOW ACROSS KANSAS. THIS SHOULD PUT AT LEAST OUR SOUTHERN CWA IN DECENT QG FORCING LATE TUESDAY NIGHT INTO WEDNESDAY. MODELS DIVERGE ON HOW THEY HANDLE MOISTURE ADVECTION INTO THE AREA. WITH STRONGER SHORTWAVE RIDGING AND HIGH PRESSURE TO THE NORTH...ECMWF AND SREF KEEP THE DEEPER MOISTURE AND PRECIP TO OUR SOUTH...WHILE THE GFS AND NAM PUSH IT UP TO INTERSTATE 90 ON WEDNESDAY. GIVEN MODEL UNCERTAINTY WILL BLEND THE TWO SOLUTIONS...TRENDING A BIT CLOSER TO THE ECMWF AND SREF SOLUTIONS. THURSDAY AND MOST OF FRIDAY SHOULD REMAIN DRY WITH AN UPPER LEVEL RIDGE OVERHEAD. ANOTHER SHORTWAVE WILL PUSH ACROSS LATER FRIDAY INTO SATURDAY BRINGING OUR NEXT CHANCE OF SHOWERS AND POSSIBLY A THUNDERSTORM. HIGH TEMPERATURES TUESDAY THROUGH SUNDAY LOOK GENERALLY IN THE UPPER 50S TO LOWER 60S...WITH MODELS IN FAIRLY GOOD AGREEMENT WITH THESE VALUES. LOW TEMPERATURES SHOULD BE IN THE UPPER 30S TO LOWER 40S. DEPENDING ON WHAT EXACTLY HAPPENS WITH THE UPPER LOW ON WEDNESDAY...TEMPERATURES MAY NEED TO BE ADJUSTED UP A FEW DEGREES IF THE SOUTHERN SOLUTION PANS OUT...OR DOWN IF THE SHOWERS ARE MORE WIDESPREAD. /CHENARD && .AVIATION.../FOR THE 12Z TAF ISSUANCE/ ONCE AGAIN...STRATUS IS A CONCERN...AT LEAST THROUGH OUR NORTHERN AND EASTERN ZONES. WIDESPREAD LIFR TO IFR CONDITIONS WILL BE FOUND ALONG AND EAST OF AROUND A HURON SD...TO SIOUX FALLS...TO JUST EAST OF SIOUX CITY LINE...AT LEAST THROUGH LATE MORNING. SOME OF THIS STRATUS MAY LINGER RIGHT INTO EARLY AFTERNOON BEFORE MIXING OUT TO A HIGHER LEVEL. DUE TO BREEZY WINDS...THE VISIBILITIES WILL NOT BE AS BAD THIS MORNING AS IN PREVIOUS MORNINGS. BUT STILL MANY CEILINGS WILL BE AT OR BELOW 500 FEET AGL. IT IS PROBLEMATIC WHETHER THE VERY LOW CEILINGS WILL MAKE IT INTO THE KHON TAF. AS OF THIS TIME... VARIOUS MODELS ARE HINTING AT SOME TEMPORARY STRATUS DEVELOPMENT AT HURON A LITTLE LATER THIS MORNING...BUT A BIT HIGHER AT JUST INSIDE THE MVFR CATEGORY. THIS WILL HAVE TO BE MONITORED CLOSELY. IN ADDITION...ALL INDICATIONS ARE THAT THE STRATUS WILL NOT MAKE IT TO KSUX. BUT WOULD NOT BE SURPRISED TO SEE A FEW SHREDS OF STRATUS IN THE SCATTERED CATEGORY AFTER SUNRISE. THE COLD FRONT WILL ADVANCE ACROSS OUR SD COUNTIES VERY SLOWLY TODAY...AND SLOWED DOWN THE WIND SHIFT AT KFSD AND KSUX. SOME MVFR CEILINGS MAY BE FOUND IN OUR WESTERN ZONES BEHIND THE FRONT ALL AFTERNOON WITH LIGHT SHOWERS...WHICH WILL LIKELY IMPACT THE KHON TAF. MVFR CEILINGS WILL PROBABLY THEN WORK THEIR WAY FROM WEST TO EAST TONIGHT AND ENCOMPASS MOST OF THE FORECAST AREA IN DOING SO. NORTHERLY WINDS WILL ALSO BE STRONG BEHIND THE FRONT...MAINLY ALONG AND WEST OF THE JAMES RIVER VALLEY...AVERAGING 25 TO 35 KNOTS...WITH SOME GUSTS OF 40 TO 45 KNOTS AS YOU APPROACH CENTRAL SD. THE WINDS WILL DECREASE SOME TONIGHT. LASTLY...IT WILL BECOME QUITE WARM AGAIN TODAY THROUGHOUT NORTHWEST IOWA. THIS HEATING MAY BE ENOUGH TO BREAK CAPPING IN THOSE ZONES PRODUCING AN ISOLATED LATE AFTERNOON OR EARLY EVENING THUNDERSTORM. /MJF && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...WIND ADVISORY FROM 10 AM TO 9 PM CDT MONDAY FOR SDZ038-039- 052>054-058>061-064>066-068-069. WIND ADVISORY FROM 7 AM TO 9 PM CDT MONDAY FOR SDZ050-057-063. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
500 AM CDT MON APR 2 2012 .DISCUSSION.../ISSUED AT 500 AM CDT/ CURRENTLY SEEING A COLD FRONT PUSHING INTO OUR WESTERN CWA...HAVING JUST PUSHED THROUGH CHAMBERLAIN...AND A WARM FRONT DRAPED FROM EAST OF HURON SOUTH ACROSS SIOUX FALLS INTO NORTHWEST IOWA. EXPECTATION IS THAT THIS WARM FRONT WILL CONTINUE TO SLOWLY DRIFT SOUTHWEST...WITH THE AREA OF LOW STRATUS ACCOMPANYING IT. GUIDANCE CONTINUES TO SLOW DOWN THE PROGRESSION OF THE COLD FRONT. MODELS COMING INTO AGREEMENT THAT IT WILL WILL SLOWLY PUSH EAST THROUGH THE DAY...NOT PASSING THROUGH SIOUX FALLS UNTIL 20-22Z...AND THE EASTERN EDGE OF THE CWA 2-4Z. THIS WILL IMPACT TODAYS TEMPERATURE AND WIND POTENTIAL. TEMPERATURES ARE A BIG QUESTION MARK WITH A LARGE SPREAD IN THE GUIDANCE TODAY. WITH THE SLOWER ARRIVAL OF THE COLD FRONT...RAISED TEMPERATURES SEVERAL DEGREES IN THE WEST. MEANWHILE...FROM SIOUX FALLS TO SIOUX CITY AND POINTS EAST...TEMPERATURES DEPEND ON PROGRESSION OF THE WARM FRONT AND ATTENDANT LOW CLOUDS. THE HRRR HAS PERFORMED FAIRLY WELL THE PAST COUPLE DAYS WITH THE EVOLUTION OF THE WARM FRONT AND CLOUDS. IT LIFTS THE FRONT NORTH ALMOST THROUGH THE ENTIRE CWA...RESULTING IN HIGHS IN THE 80S FROM YANKTON TO SIOUX FALLS AND POINTS EAST...WITH NEAR 90 ONCE AGAIN IN SIOUX CITY. THIS IS THE WARMEST MODEL SOLUTION...BUT THE NAM AND ECMWF ARE ONLY A FEW DEGREES COOLER. THE LOW LEVEL MOISTURE AND STRATUS WILL BE A BIT DEEPER THIS MORNING COMPARED TO LAST...SO THINK IT MAY TAKE A BIT LONGER FOR CLOUDS TO ERODE. BUT GIVEN WHAT HAS HAPPENED THE PAST FEW DAYS...THE SLOWER COLD FRONT...AND MODEL AGREEMENT...CURRENT THINKING IS THAT THEY DO INDEED ERODE...ALLOWING FOR ANOTHER VERY WARM DAY WITH HIGHS IN THE UPPER 70S TO MID 80S ACROSS EXTREME SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA. GIVEN UNCERTAINTY...DID NOT GO QUITE AS WARM AS WARMEST SOLUTIONS...BUT WOULD NOT BE SURPRISED IF TEMPS END UP A FEW DEGREES WARMER THAN CURRENT FORECAST. ON THE OTHER HAND...IF THE LOW CLOUDS STAY LOCKED IN TEMPERATURES WILL BE MUCH COOLER THAN FORECAST...ALTHOUGH SEE THIS AS A LOWER PROBABILITY EVENT AT THIS TIME. NEXT UP IS THE WINDS. WINDS WILL BECOME STRONG BEHIND THE COLD FRONT. 900MB WINDS ARE EXPECTED TO BE IN THE 30 TO 40 KTS RANGE. THE COMBINATION OF DECENT LOW LEVEL CAA AND PRESSURE RISES WILL HELP PROMOTE MIXING AND THE TRANSFER OF THESE WINDS TO THE SURFACE. A BORDERLINE WIND ADVISORY EVENT...BUT WILL KEEP THE CURRENT ADVISORY MAINLY AS IS...WITH SUSTAINED WINDS APPROACHING 30 MPH FOR A PERIOD IN THE WEST...WITH A FEW GUSTS AROUND 40 MPH. DID CUT ONE ROW OF COUNTIES OFF THE ADVISORY GIVEN THE SLOWER MOVEMENT OF THE FRONT AND A SLIGHTLY WEAKER CORE OF LOW LEVEL WINDS. PRECIP CHANCES LOOK TO BE CLOSE TO ZERO OUT AHEAD OF THE FRONT. SOME ELEVATED CAPE IN OUR FAR NORTHWEST...BUT A STRONG CAPPING INVERSION AROUND 750MB WILL PREVENT ANY ELEVATED CONVECTION. DEEP LOW LEVEL MOISTURE BEHIND THE FRONT WILL ALLOW FOR DRIZZLE AND LIGHT SHOWERS...MAINLY NORTH OF INTERSTATE 90 AND WEST OF INTERSTATE 29. EXPECT THIS AREA OF DRIZZLE TO BEGIN TO DISSIPATE TONIGHT AS THE MOISTURE LAYER BECOMES SHALLOW AND BEGINS TO ERODE AWAY FROM WEST TO EAST. NAM AND GFS BOTH SHOWING DECENT ELEVATED CAPE BEHIND THE COLD FRONT FROM PARCELS UP AROUND 750MB. IT LOOKS LIKE WE SHOULD REMAIN CAPPED...HOWEVER STRONG LOW LEVEL LIFT GENERATED BY THE DEVELOPING LOW PRESSURE AND THETAE ADVECTION MAY ATTEMPT TO BREAK THIS CAP. AND WITH MOISTURE UP TO 750MB...NOT OUT OF THE QUESTION THAT THOSE PARCELS GO AND WE GET A THUNDERSTORM. BEST CHANCE OF THIS APPEARS TO BE ACROSS SOUTHWEST MINNESOTA BETWEEN 0Z AND 6Z...WHERE THE LIFT IS STRONGEST AND MOISTURE DEEPEST. OTHER CONCERN IS ACROSS NORTHWEST IOWA. WITH THE VERY WARM TEMPERATURES WILL LIKELY SEE CAPES AROUND 2000 J/KG THIS AFTERNOON. HOWEVER EXPECT THE STRONG MID LEVEL CAP TO HOLD. IF WE GET HOTTER THAN FORECAST THE DEEPER MIXING SHOULD RESULT IN LOWER DEWPOINTS...WITH THE NET RESULT OF BEING CAPPED STAYING THE SAME. THIS IS SUPPORTED BY THE NAM AND HRRR. SHORTWAVE RIDGING SHOULD PROVIDE A DRY DAY TUESDAY. OUR NEXT WEATHER FEATURE IS A CUT OFF LOW ACROSS THE SOUTHERN PLAINS. NAM...GFS AND ECMWF HAVE SIMILAR TRACKS OF THE UPPER LEVEL LOW ACROSS KANSAS. THIS SHOULD PUT AT LEAST OUR SOUTHERN CWA IN DECENT QG FORCING LATE TUESDAY NIGHT INTO WEDNESDAY. MODELS DIVERGE ON HOW THEY HANDLE MOISTURE ADVECTION INTO THE AREA. WITH STRONGER SHORTWAVE RIDGING AND HIGH PRESSURE TO THE NORTH...ECMWF AND SREF KEEP THE DEEPER MOISTURE AND PRECIP TO OUR SOUTH...WHILE THE GFS AND NAM PUSH IT UP TO INTERSTATE 90 ON WEDNESDAY. GIVEN MODEL UNCERTAINTY WILL BLEND THE TWO SOLUTIONS...TRENDING A BIT CLOSER TO THE ECMWF AND SREF SOLUTIONS. THURSDAY AND MOST OF FRIDAY SHOULD REMAIN DRY WITH AN UPPER LEVEL RIDGE OVERHEAD. ANOTHER SHORTWAVE WILL PUSH ACROSS LATER FRIDAY INTO SATURDAY BRINGING OUR NEXT CHANCE OF SHOWERS AND POSSIBLY A THUNDERSTORM. HIGH TEMPERATURES TUESDAY THROUGH SUNDAY LOOK GENERALLY IN THE UPPER 50S TO LOWER 60S...WITH MODELS IN FAIRLY GOOD AGREEMENT WITH THESE VALUES. LOW TEMPERATURES SHOULD BE IN THE UPPER 30S TO LOWER 40S. DEPENDING ON WHAT EXACTLY HAPPENS WITH THE UPPER LOW ON WEDNESDAY...TEMPERATURES MAY NEED TO BE ADJUSTED UP A FEW DEGREES IF THE SOUTHERN SOLUTION PANS OUT...OR DOWN IF THE SHOWERS ARE MORE WIDESPREAD. /CHENARD && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ EXPECT REDEVELOPMENT OF STRATUS/FOG OVER NORTHEAST HALF OF THE AREA THROUGH THE REMAINDER OF TONIGHT/EARLY MONDAY. POTENTIAL FOR LIFR VISIBILITY...ESPECIALLY IN HIGHER ELEVATIONS ACROSS SOUTHWEST MN AS STRATUS CURRENTLY DEVELOPING ACROSS NORTHERN IOWA ADVECTS INTO OUR FORECAST AREA ON PERSISTENT EAST-SOUTHEAST LOW LEVEL FLOW. THESE IFR-LIFR CONDITIONS EXPECTED TO ADVECT WESTWARD THROUGH INTERSTATE 29 CORRIDOR AFTER 09Z-10Z...WITH IFR-LIFR CONDITIONS PERSISTING THROUGH 14Z-15Z. WHILE VISIBILITY EXPECTED TO IMPROVE THEREAFTER... CONTINUED EAST-SOUTHEAST FLOW WILL LIKELY LOCK STRATUS IN PLACE INTO THE EARLY-MID AFTERNOON. LATEST MODELS SLOWER WITH EASTWARD PUSH OF COLD FRONT...WHICH WILL BE NEEDED TO COMPLETELY SCOUR OUT THE LOW LEVEL MOISTURE. BEHIND THE FRONT...WESTERN AREAS WILL SEE INCREASING NORTHERLY WINDS BEGIN TO GUST OVER 25KTS BY 14Z-16Z...WITH SCATTERED LIGHT SHOWERS ALONG WITH BROKEN MVFR CEILINGS MORE LIKELY IN POST-FRONTAL AIRMASS THAN AHEAD OF THE BOUNDARY. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...NONE. MN...NONE. NE...NONE. SD...WIND ADVISORY FROM 10 AM TO 9 PM CDT MONDAY FOR SDZ038-039- 052>054-058>061-064>066-068-069. WIND ADVISORY FROM 7 AM TO 9 PM CDT MONDAY FOR SDZ050-057-063. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
519 PM CDT MON APR 2 2012 .UPDATE... A QUICK UPDATE WAS SENT TO REMOVE WW127...THE SEVERE THUNDERSTORM WATCH THAT COVERED SOME OF THE EASTERN NORTH TEXAS UNTIL 7 PM. SHOWERS AND THUNDERSTORMS NORTHEAST OF A SHERMAN TO SULPHUR SPRINGS LINE WILL CONTINUE TO MOVE NORTHEAST AND SEVERE WEATHER IS NOT EXPECTED TO DEVELOP ACROSS THE AREA PREVIOUSLY IN WW127. OUR EYES WILL NOW BE TRAINED ALONG THE DRYLINE WHERE ACTIVITY IS EXPECTED TO DEVELOP DURING THE NEXT HOUR. 58 && .PREV DISCUSSION... /ISSUED 307 PM CDT MON APR 2 2012/ MAIN UPPER LOW FEATURE SITS ACROSS CENTRAL NEW MEXICO. WEAK LOBE THAT WAS NEAR TX COAST YESTERDAY HAS ROTATED NORTH AND SITS OVER THE DFW METROPLEX. CIRCULATION AROUND THE WEAK LOW AND ASSOCIATED SHORT WAVE HAS FIRED OFF SEVERE STORMS IN EASTERN NORTH TEXAS...BUT AS THIS SYSTEM MOVES ON NORTH WE FEEL THAT THE DRY LINE WILL BECOME THE MAIN PLAYER FOR TONIGHT AND TOMORROW. GUIDANCE AGREES ON A GENERAL SOLUTION OF THE UPPER LOW PUSHING EAST AND THEN NORTHEAST TO LIE OVER THE TX/OK PANHANDLES ON TUESDAY. THE UPPER LOW MOVEMENT PUSHES THE DRY LINE ACROSS NORTH TEXAS ON TUESDAY AS WELL. THE DISAGREEMENT IS ABOUT HOW CONVECTION WILL EVOLVE WITH THE SYSTEM. THE LATEST RUC ACTIVATES THE DRY LINE EARLY THIS EVENING. THE NAM INITIATES DRY LINE CONVECTION WELL AFTER MIDNIGHT AS DOES THE LATEST HRRR. WITH SOME CU ALREADY DEVELOPING WEST OF THE CWA...WILL STICK WITH OUR PREVIOUS SOLUTION WHICH AGREES WITH THE RUC AND THE GFS FOR DRY LINE CONVECTION THIS AFTERNOON/EVENING MOVING INTO NORTHWEST COUNTIES. EITHER CONVECTION WILL MAINTAIN IN SOME FORM OVERNIGHT AND REINVIGORATE TOMORROW WITH DAYTIME HEATING...OR IT MAY DIE OUT AND REGENERATE TOMORROW. EITHER WAY...WE HAVE HIGHER CONFIDENCE OF A LINEAR FEATURE DEVELOPING DURING THE DAY TOMORROW AS THE DRY LINE PUSHES EAST. WITH STEEP LAPSE RATES LARGE HAIL AND DAMAGING WINDS ARE LIKELY TO OCCUR. STORMS SHOULD SWEEP EAST OF THE AREA BY LATE EVENING OR EARLY WEDNESDAY MORNING...AND POPS END SUNRISE WEDNESDAY. THE NAM IS AN OUTLIER...HOLDING THE DRY LINE BACK ABOUT 8 HOURS BEHIND THE GFS...AND IF THIS OCCURS WE WOULD HAVE TO ADD POPS FOR WEDNESDAY MORNING. SHORT WAVE RIDGING MOVES IN WEDNESDAY AFTERNOON...AND NORTH TX SHOULD REMAIN DRY THROUGH SUNDAY MORNING...WHEN A NEW FRONT IS EXPECTED TO DROP INTO THE AREA AND INCREASE THE POPS A BIT. 84 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 66 81 54 80 55 / 40 60 40 5 0 WACO, TX 67 79 54 83 55 / 20 60 30 5 0 PARIS, TX 65 79 59 81 54 / 20 50 60 10 0 DENTON, TX 65 79 54 78 54 / 40 60 30 5 0 MCKINNEY, TX 66 81 54 80 55 / 30 60 40 5 0 DALLAS, TX 66 82 55 81 55 / 30 60 40 5 0 TERRELL, TX 66 80 60 80 55 / 20 60 50 10 0 CORSICANA, TX 67 81 61 81 55 / 20 60 50 10 0 TEMPLE, TX 67 78 58 84 55 / 20 60 30 5 0 MINERAL WELLS, TX 64 77 53 81 52 / 50 40 10 5 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 30/58
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
307 PM CDT MON APR 2 2012 .DISCUSSION... MAIN UPPER LOW FEATURE SITS ACROSS CENTRAL NEW MEXICO. WEAK LOBE THAT WAS NEAR TX COAST YESTERDAY HAS ROTATED NORTH AND SITS OVER THE DFW METROPLEX. CIRCULATION AROUND THE WEAK LOW AND ASSOCIATED SHORT WAVE HAS FIRED OFF SEVERE STORMS IN EASTERN NORTH TEXAS...BUT AS THIS SYSTEM MOVES ON NORTH WE FEEL THAT THE DRY LINE WILL BECOME THE MAIN PLAYER FOR TONIGHT AND TOMORROW. GUIDANCE AGREES ON A GENERAL SOLUTION OF THE UPPER LOW PUSHING EAST AND THEN NORTHEAST TO LIE OVER THE TX/OK PANHANDLES ON TUESDAY. THE UPPER LOW MOVEMENT PUSHES THE DRY LINE ACROSS NORTH TEXAS ON TUESDAY AS WELL. THE DISAGREEMENT IS ABOUT HOW CONVECTION WILL EVOLVE WITH THE SYSTEM. THE LATEST RUC ACTIVATES THE DRY LINE EARLY THIS EVENING. THE NAM INITIATES DRY LINE CONVECTION WELL AFTER MIDNIGHT AS DOES THE LATEST HRRR. WITH SOME CU ALREADY DEVELOPING WEST OF THE CWA...WILL STICK WITH OUR PREVIOUS SOLUTION WHICH AGREES WITH THE RUC AND THE GFS FOR DRY LINE CONVECTION THIS AFTERNOON/EVENING MOVING INTO NORTHWEST COUNTIES. EITHER CONVECTION WILL MAINTAIN IN SOME FORM OVERNIGHT AND REINVIGORATE TOMORROW WITH DAYTIME HEATING...OR IT MAY DIE OUT AND REGENERATE TOMORROW. EITHER WAY...WE HAVE HIGHER CONFIDENCE OF A LINEAR FEATURE DEVELOPING DURING THE DAY TOMORROW AS THE DRY LINE PUSHES EAST. WITH STEEP LAPSE RATES LARGE HAIL AND DAMAGING WINDS ARE LIKELY TO OCCUR. STORMS SHOULD SWEEP EAST OF THE AREA BY LATE EVENING OR EARLY WEDNESDAY MORNING...AND POPS END SUNRISE WEDNESDAY. THE NAM IS AN OUTLIER...HOLDING THE DRY LINE BACK ABOUT 8 HOURS BEHIND THE GFS...AND IF THIS OCCURS WE WOULD HAVE TO ADD POPS FOR WEDNESDAY MORNING. SHORT WAVE RIDGING MOVES IN WEDNESDAY AFTERNOON...AND NORTH TX SHOULD REMAIN DRY THROUGH SUNDAY MORNING...WHEN A NEW FRONT IS EXPECTED TO DROP INTO THE AREA AND INCREASE THE POPS A BIT. 84 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 66 81 54 80 55 / 40 60 40 5 0 WACO, TX 67 79 54 83 55 / 20 60 30 5 0 PARIS, TX 65 79 59 81 54 / 20 50 60 10 0 DENTON, TX 65 79 54 78 54 / 40 60 30 5 0 MCKINNEY, TX 66 81 54 80 55 / 30 60 40 5 0 DALLAS, TX 66 82 55 81 55 / 30 60 40 5 0 TERRELL, TX 66 80 60 80 55 / 20 60 50 10 0 CORSICANA, TX 67 81 61 81 55 / 20 60 50 10 0 TEMPLE, TX 67 78 58 84 55 / 20 60 30 5 0 MINERAL WELLS, TX 64 77 53 81 52 / 50 40 10 5 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
635 AM CDT MON APR 2 2012 .AVIATION... AN MCS PROPAGATING UP THE COASTAL PLAIN FROM MATAGORDA BAY WILL LIKELY AFFECT THE AIRPORTS FROM KCXO SOUTH TO THE COAST THIS MORNING THROUGH 15Z. GIVEN THE UNSTABLE AIR MASS AND THE LOCATION OF THE STRONGEST WINDS AT 1130Z...INDICATED WIND GUSTS TO 35 KNOTS POSSIBLE FOR KLBX AND KGLS. HOWEVER...MAY NEED TO ADJUST THESE FURTHER INLAND. THE MODEL FORECASTS DIFFERED FOR TODAY. THE 4 KM NCEP WRF INITIALIZED AND HAS HANDLED THE MCS WELL THIS MORNING. COMBINED THE WRF AND RUC FOR THE THUNDERSTORM FORECAST FOR TODAY. OUTSIDE OF STORMS...VFR IS EXPECTED THIS AFTERNOON ALONG WITH BREEZY WINDS. MVFR IS EXPECTED TO DEVELOP BY AROUND 06Z INLAND AND AFTER 03Z TOWARD AND ALONG THE COAST. IFR IS POSSIBLE MAINLY OVERNIGHT TONIGHT...ESPECIALLY IF A GIVEN LOCATION RECEIVES RAINFALL TODAY. 40 && .PREV DISCUSSION... /ISSUED 408 AM CDT MON APR 2 2012/ DISCUSSION... A WEAK UPPER LEVEL CIRCULATION WAS SPINNING NORTH OF MATAGORDA BAY THIS MORNING. THIS FEATURE WILL SLOWLY MOVE NORTH NORTHEAST INTO NORTHWEST LOUISIANA BY EVENING. ANOTHER UPPER LEVEL DISTURBANCE OVER SOUTH TEXAS IS TRIGGERING SHOWERS AND THUNDERSTORMS OVER SOUTH TEXAS AND THE MIDDLE TEXAS COAST. THIS DISTURBANCE IS MOVING EAST AND THE ASSOCIATED PRECIP SHOULD BEGIN TO MOVE OVER PARTS OF THE CWA BY 5 AM. MODELS ARE NOT DOING A GREAT JOB WITH THE SMALL SCALE DETAILS AND SHORT TERM GUIDANCE HAS INITIALIZED POORLY. THAT SAID...FEEL THE DEEPER MOISTURE WILL REMAIN EAST OF THE UPPER CIRCULATION NORTH OF MATAGORDA BAY. BEST RAIN CHANCES SHOULD LIE TO THE EAST OF THE I-45 CORRIDOR AND SOUTH OF HWY 105. THE SYSTEM WILL STRENGTHEN THIS AFTERNOON AND HEAVIER RAIN WILL BEGIN TO DEVELOP AND HEAD TOWARD LOUISIANA. IF THE SYSTEM TRACKS FURTHER WEST THAN CURRENTLY FCST...SOME OF THE MORE ORGANIZED HEAVIER RAIN WILL ALSO SHIFT WEST AND INTO HOUSTON. LOOKING SOUTH...THE LINE OF STORMS OVER SOUTH TEXAS IS MAKING STEADY PROGRESS EAST THIS MORNING. SHORT TERM GUIDANCE IS WELL BEHIND THE CURVE WITH THE PLACEMENT OF THE PRECIP. THE 06Z RUC IS BEGINNING TO CATCH ON AND IT BRINGS A WEAK LINE OF SHOWERS INTO THE REGION...WEST OF I-45 BY 15Z. THE 4KM WRF SEEMS TO BE DOING A GOOD JOB WITH THIS AREA OF CONVECTION (COMPLETELY MISSED THE PRECIP OVER LOUISIANA). THE WRF BRINGS THIS LINE OF STORMS INTO AND ACROSS SOUTHEAST TEXAS THIS MORNING...EXITING THE THE REGION BY 19Z. WILL HEDGE MY BETS AND GO WITH CHANCE POPS SOUTH AND SLIGHT CHANCE NORTH. WILL WATCH TRENDS AND POPS MAY BE NUDGED UPWARD LATER THIS MORNING IF TRENDS WARRANT. SPC HAS OUTLOOKED THE EXTREME NORTHERN PORTION OF SE TX IN SLIGHT RISK FOR THIS AFTERNOON AND EVENING. FCST SOUNDINGS SHOW A GREAT DEAL OF INSTABILITY (CAPE ABOVE 3000 AND LI`S AROUND -10)...BUT THERE IS STILL SOME WEAK CAPPING TO OVERCOME. THE PROBABILITY OF OCCURRENCE SHOULD REMAIN SLIGHT BUT THERE IS SOME POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS AND LARGE HAIL. THE THREAT AREA IS NORTH OF A BRENHAM TO HUNTSVILLE TO CLEVELAND LINE. THERE SHOULD BE A BREAK IN THE PRECIP TONIGHT AS THE MORNING SYSTEM IS EAST OF THE REGION AND THE NEXT STRONG UPPER LEVEL SYSTEM IS STILL OVER NEW MEXICO. THE UPPER LEVEL LOW OUT WEST WILL MOVE NORTHEAST ON TUESDAY. NAM AND GFS DIFFER WITH MOISTURE PROFILES BUT CAPPING IS WEAK AND UPPER LEVEL WINDS BECOME INCREASINGLY DIVERGENT. WILL GO WITH HIGH END CHANCE POPS FOR TUESDAY/TUES NIGHT. NOT SURE WHEN THINGS WILL CLEAR. THE ECMWF...NAM AND CANADIAN HOLD ONTO THE PRECIP THROUGH WEDNESDAY MORNING WHILE THE GFS CLEARS THINGS OUT RATHER QUICKLY. PREFER THE SLOWER CLEARING SINCE THE DRY LINE/WEAK FRONT NEVER REALLY CLEARS THE COAST. THE UPPER LEVEL LOW WILL BE EAST OF THE REGION ON THURSDAY AND AN UPPER LEVEL RIDGE WILL BEGIN TO AMPLIFY OVER THE SOUTHERN PLAINS. PRECIP SHOULD REMAIN NORTH AND WEST OF THE REGION THURSDAY THROUGH SATURDAY WITH ANOTHER WARM UP UNDERWAY. MAX TEMPS TOWARD THE END OF THE WEEK WILL BE BACK INTO THE MID/UPPER 80S. 43 MARINE... AS AN UPPER LOW MOVES ACROSS THE INLAND AREAS...THUNDERSTORMS WILL BE POSSIBLE TODAY OVER THE BAYS AND COASTAL WATERS. ALTHOUGH THE FORECAST MODELS DIFFERED...THERE WAS ENOUGH SIMILARITIES TO SUGGEST MODERATE ONSHORE WINDS WILL AFFECT THE MARINE AREAS TODAY THROUGH TUESDAY. A COLD FRONT SHOULD APPROACH THE COAST FROM THE NORTHWEST LATE TUESDAY AND EARLY WEDNESDAY MORNING. FOR NOW IT APPEARS THAT THE FRONT MAY WELL STAY INLAND OR MOVE JUST OFFSHORE BEFORE RETURNING BACK TO THE NORTH LATE WEDNESDAY AND THURSDAY. AM EXPECTING ONSHORE WINDS TO THEN RETURN AND PERSIST THROUGH THE END OF THE WEEK. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 83 70 80 64 82 / 30 20 50 50 10 HOUSTON (IAH) 84 71 83 67 85 / 30 20 50 50 20 GALVESTON (GLS) 81 73 81 71 81 / 40 20 50 50 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH THIS EVENING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...43 AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
408 AM CDT MON APR 2 2012 .DISCUSSION... A WEAK UPPER LEVEL CIRCULATION WAS SPINNING NORTH OF MATAGORDA BAY THIS MORNING. THIS FEATURE WILL SLOWLY MOVE NORTH NORTHEAST INTO NORTHWEST LOUISIANA BY EVENING. ANOTHER UPPER LEVEL DISTURBANCE OVER SOUTH TEXAS IS TRIGGERING SHOWERS AND THUNDERSTORMS OVER SOUTH TEXAS AND THE MIDDLE TEXAS COAST. THIS DISTURBANCE IS MOVING EAST AND THE ASSOCIATED PRECIP SHOULD BEGIN TO MOVE OVER PARTS OF THE CWA BY 5 AM. MODELS ARE NOT DOING A GREAT JOB WITH THE SMALL SCALE DETAILS AND SHORT TERM GUIDANCE HAS INITIALIZED POORLY. THAT SAID...FEEL THE DEEPER MOISTURE WILL REMAIN EAST OF THE UPPER CIRCULATION NORTH OF MATAGORDA BAY. BEST RAIN CHANCES SHOULD LIE TO THE EAST OF THE I-45 CORRIDOR AND SOUTH OF HWY 105. THE SYSTEM WILL STRENGTHEN THIS AFTERNOON AND HEAVIER RAIN WILL BEGIN TO DEVELOP AND HEAD TOWARD LOUISIANA. IF THE SYSTEM TRACKS FURTHER WEST THAN CURRENTLY FCST...SOME OF THE MORE ORGANIZED HEAVIER RAIN WILL ALSO SHIFT WEST AND INTO HOUSTON. LOOKING SOUTH...THE LINE OF STORMS OVER SOUTH TEXAS IS MAKING STEADY PROGRESS EAST THIS MORNING. SHORT TERM GUIDANCE IS WELL BEHIND THE CURVE WITH THE PLACEMENT OF THE PRECIP. THE 06Z RUC IS BEGINNING TO CATCH ON AND IT BRINGS A WEAK LINE OF SHOWERS INTO THE REGION...WEST OF I-45 BY 15Z. THE 4KM WRF SEEMS TO BE DOING A GOOD JOB WITH THIS AREA OF CONVECTION (COMPLETELY MISSED THE PRECIP OVER LOUISIANA). THE WRF BRINGS THIS LINE OF STORMS INTO AND ACROSS SOUTHEAST TEXAS THIS MORNING...EXITING THE THE REGION BY 19Z. WILL HEDGE MY BETS AND GO WITH CHANCE POPS SOUTH AND SLIGHT CHANCE NORTH. WILL WATCH TRENDS AND POPS MAY BE NUDGED UPWARD LATER THIS MORNING IF TRENDS WARRANT. SPC HAS OUTLOOKED THE EXTREME NORTHERN PORTION OF SE TX IN SLIGHT RISK FOR THIS AFTERNOON AND EVENING. FCST SOUNDINGS SHOW A GREAT DEAL OF INSTABILITY (CAPE ABOVE 3000 AND LI`S AROUND -10)...BUT THERE IS STILL SOME WEAK CAPPING TO OVERCOME. THE PROBABILITY OF OCCURRENCE SHOULD REMAIN SLIGHT BUT THERE IS SOME POTENTIAL FOR STORMS TO PRODUCE DAMAGING WINDS AND LARGE HAIL. THE THREAT AREA IS NORTH OF A BRENHAM TO HUNTSVILLE TO CLEVELAND LINE. THERE SHOULD BE A BREAK IN THE PRECIP TONIGHT AS THE MORNING SYSTEM IS EAST OF THE REGION AND THE NEXT STRONG UPPER LEVEL SYSTEM IS STILL OVER NEW MEXICO. THE UPPER LEVEL LOW OUT WEST WILL MOVE NORTHEAST ON TUESDAY. NAM AND GFS DIFFER WITH MOISTURE PROFILES BUT CAPPING IS WEAK AND UPPER LEVEL WINDS BECOME INCREASINGLY DIVERGENT. WILL GO WITH HIGH END CHANCE POPS FOR TUESDAY/TUES NIGHT. NOT SURE WHEN THINGS WILL CLEAR. THE ECMWF...NAM AND CANADIAN HOLD ONTO THE PRECIP THROUGH WEDNESDAY MORNING WHILE THE GFS CLEARS THINGS OUT RATHER QUICKLY. PREFER THE SLOWER CLEARING SINCE THE DRY LINE/WEAK FRONT NEVER REALLY CLEARS THE COAST. THE UPPER LEVEL LOW WILL BE EAST OF THE REGION ON THURSDAY AND AN UPPER LEVEL RIDGE WILL BEGIN TO AMPLIFY OVER THE SOUTHERN PLAINS. PRECIP SHOULD REMAIN NORTH AND WEST OF THE REGION THURSDAY THROUGH SATURDAY WITH ANOTHER WARM UP UNDERWAY. MAX TEMPS TOWARD THE END OF THE WEEK WILL BE BACK INTO THE MID/UPPER 80S. 43 && MARINE... AS AN UPPER LOW MOVES ACROSS THE INLAND AREAS...THUNDERSTORMS WILL BE POSSIBLE TODAY OVER THE BAYS AND COASTAL WATERS. ALTHOUGH THE FORECAST MODELS DIFFERED...THERE WAS ENOUGH SIMILARITIES TO SUGGEST MODERATE ONSHORE WINDS WILL AFFECT THE MARINE AREAS TODAY THROUGH TUESDAY. A COLD FRONT SHOULD APPROACH THE COAST FROM THE NORTHWEST LATE TUESDAY AND EARLY WEDNESDAY MORNING. FOR NOW IT APPEARS THAT THE FRONT MAY WELL STAY INLAND OR MOVE JUST OFFSHORE BEFORE RETURNING BACK TO THE NORTH LATE WEDNESDAY AND THURSDAY. AM EXPECTING ONSHORE WINDS TO THEN RETURN AND PERSIST THROUGH THE END OF THE WEEK. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 83 70 80 64 82 / 20 20 50 50 10 HOUSTON (IAH) 84 71 83 67 85 / 30 20 50 50 20 GALVESTON (GLS) 81 73 81 71 81 / 40 20 50 50 20 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1130 PM CDT SUN APR 1 2012 .DISCUSSION... SEE AVIATION FOR 06Z TAFS. && .AVIATION... THE MODERATE PRESSURE GRADIENT ACROSS SOUTH CENTRAL TEXAS WILL INCREASE THROUGH MONDAY...IN ADVANCE OF A STORM SYSTEM THAT WILL BRING INCREASING CHANCES OF RAIN LATE MONDAY THROUGH TUESDAY. ISOLATED SHRA AND TSRA WILL CONTINUE OVER THE SOUTHWEST TO SOUTH PART OF SOUTH CENTRAL TEXAS FOR THE NEXT FEW HOURS. CIGS WILL CONTINUE TO FORM AROUND 1 THSD TO 2 THSD FT FROM KAUS TO KSAT AND VCNTY OF KDRT AROUND OR AFTER 09Z TONIGHT. CIGS OF 500 TO 900 FT OVC ARE POSSIBLE VCNTY OF KAUS TO KSAT FROM 07Z TO 16Z MONDAY. PATCHY FOG MAY DEVELOP WITH VSBYS 3 TO 6 MILES IN FOG/HAZE. CIGS WILL BECOME 1 THSD TO 2 THSD BKN TO OVC AFTER 16Z MONDAY...AND THEN INCREASE TO CIGS 3 THSD TO 5 THSD BKN AFTER 19Z MONDAY AFTERNOON. SOUTH AND SOUTHEAST WINDS NEAR 10 KNOTS WILL PICKUP TO 15 TO 20 KNOTS MONDAY...IN ADVANCE OF A STORM SYSTEM...THAT WILL BRING INCREASING CHANCES OF SHOWERS OR THUNDERSTORMS TO SOUTH CENTRAL TEXAS TAF SITES ON MONDAY NIGHT THROUGH TUESDAY. MVFR CIGS WILL FORM OVER SOUTH CENTRAL TEXAS MONDAY NIGHT AFTER 03Z AROUND 1 THSD TO 2 THSD FT OVC. THE STORM SYSTEM THAT BRINGS A CHANCE OF SHOWERS AND THUNDERSTORMS LATE MONDAY THROUGH TUESDAY IS FORECAST TO MOVE TO THE TEXAS PANHANDLE AND WESTERN OK TUESDAY...AND THEN MOVE EAST LATE TUESDAY THROUGH WEDNESDAY. AS THE LOW TRACKS EAST...NORTH OF SOUTH CENTRAL TEXAS TUESDAY NIGHT AND WEDNESDAY...SCATTERED WRAP AROUND CLOUDS COULD IMPACT THE SOUTH CENTRAL TEXAS TAF SITES...AS MORE PREVAILING WEST TO NORTHWEST SFC WINDS DEVELOP...IN A PATTERN SIMILAR TO THE WEATHER IN MARCH. && .PREV DISCUSSION... /ISSUED 906 PM CDT SUN APR 1 2012/ UPDATE... RAISED POPS THROUGH 06Z OUT WEST. DISCUSSION... STORMS WHICH ORIGINATED EARLIER THIS AFTERNOON ACROSS THE SERRANIAS DEL BURRO HAVE MADE GOOD EASTWARD PROGRESSION OVER THE LAST FEW HOURS INTO THE RIO GRANDE PLAINS. THE STRONGEST THUNDERSTORMS IN THIS COMPLEX HAVE PRODUCED SMALL HAIL (PEA TO NEAR HALF-INCH)...AND COULD SEE ANOTHER FEW ROUNDS OF HAIL (POSSIBLY REACHING SEVERE LEVELS) THIS EVENING AS THE STORMS PULSE. LATEST RUC ANALYSIS SUGGEST THAT THESE STORMS WILL CONTINUE TO PUSH EASTWARD THROUGH THE NEXT FEW HOURS BEFORE DISSIPATING. HOWEVER...MODELS TYPICALLY HAVE A HARD TIME WITH MESOSCALE CONVECTIVE SYSTEMS COMING OFF OF THE MEXICAN MOUNTAINS AS FAR AS INTENSITY AND LONGEVITY...SO ADDITIONAL UPDATES MAY BE NEEDED. PREV DISCUSSION... /ISSUED 704 PM CDT SUN APR 1 2012/ DISCUSSION... SEE UPDATED AVIATION DISCUSSION FOR 00Z TAFS. AVIATION... THE PRESSURE GRADIENT WILL BE INCREASING TONIGHT THROUGH MONDAY ACROSS SOUTH CENTRAL TEXAS...AS SFC LOW PRESSURE CONTINUES TO INCREASE OVER WEST TEXAS. THIS WILL SET UP A STRONGER LOW LEVEL JET TONIGHT...AND CAUSE INCREASING LOW CLOUDINESS TONIGHT. FOR THIS EVENING 5 THSD TO 10 THSD SCT IS EXPECTED...WITH SCT CLOUDS INCREASING AT OR ABOVE 25 THSD FT. ISOLATED SHRA AND TSRA ARE POSSIBLE VCNTY OF KDRT THRU 04Z. LATER TONIGHT...CIGS WILL FORM AROUND 1 THSD TO 2 THSD FT FROM KAUS TO KSAT AROUND OR AFTER 04Z AND VCNTY OF KDRT AROUND OR AFTER 09Z TONIGHT. CIGS OF 500 TO 900 FT OVC ARE POSSIBLE VCNTY OF KAUS TO KSAT FROM 07Z TO 16Z MONDAY. CIGS WILL BECOME 1 THSD TO 2 THSD BKN TO OVC AFTER 16Z MONDAY...AND THEN INCREASE TO CIGS 3 THSD TO 5 THSD BKN AFTER 19Z MONDAY AFTERNOON. SOUTH AND SOUTHEAST WINDS NEAR 10 KNOTS WILL PICKUP TO 15 TO 20 KNOTS MONDAY...IN ADVANCE OF A STORM SYSTEM...THAT WILL BRING INCREASING CHANCES OF SHOWERS OR THUNDERSTORMS TO THE SOUTH CENTRAL TEXAS TAF SITES ON MONDAY NIGHT THROUGH TUESDAY. THIS STORM SYSTEM IS FORECAST TO MOVE TO THE TEXAS PANHANDLE AND WESTERN OK TUESDAY...AND THEN MOVE EAST LATE TUESDAY THROUGH WEDNESDAY. AS THE LOW TRACKS EAST...NORTH OF SOUTH CENTRAL TEXAS TUESDAY NIGHT AND WEDNESDAY...SCATTERED WRAP AROUND CLOUDS COULD IMPACT THE SOUTH CENTRAL TEXAS TAF SITES...AS MORE PREVAILING WEST TO NORTHWEST SFC WINDS DEVELOP...IN A PATTERN SIMILAR TO THE WEATHER IN MARCH. PREV DISCUSSION... /ISSUED 622 PM CDT SUN APR 1 2012/ DISCUSSION... SEE AVIATION FOR 00Z TAFS. AVIATION... THE PRESSURE GRADIENT WILL BE INCREASING TONIGHT THROUGH MONDAY ACROSS SOUTH CENTRAL TEXAS...AS THE SFC LOW PRESSURE CONTINUES TO INCREASE OVER WEST TEXAS. THIS WILL SET UP A STRONGER LOW LEVEL JET TONIGHT...AND CAUSE INCREASING LOW CLOUDINESS. CIGS WILL FORM AROUND 1 THSD TO 2 THSD FT FROM KAUS TO KSAT AROUND OR AFTER 04Z AND VCNTY OF KDRT AROUND OR AFTER 09Z TONIGHT. CIGS OF 500 TO 900 FT OVC ARE POSSIBLE VCNTY OF KAUS TO KSAT FROM 07Z TO 16Z MONDAY. CIGS WILL BECOME 1 THSD TO 2 THSD BKN TO OVC AFTER 16Z MONDAY...AND THEN INCREASE TO CIGS 3 THSD TO 5 THSD BKN AFTER 19Z MONDAY AFTERNOON. SOUTH AND SOUTHEAST WINDS NEAR 10 KNOTS WILL PICKUP TO 15 TO 20 KNOTS MONDAY...IN ADVANCE OF A STORM SYSTEM...THAT WILL BRING INCREASING CHANCES OF SHOWERS OR THUNDERSTORMS TO THE SOUTH CENTRAL TEXAS TAF SITES ON MONDAY NIGHT THROUGH TUESDAY. THIS STORM SYSTEM IS FORECAST TO MOVE TO THE TEXAS PANHANDLE AND WESTERN OK TUESDAY...AND THEN MOVE EAST LATE TUESDAY THROUGH WEDNESDAY. AS THE LOW TRACKS EAST... NORTH OF SOUTH CENTRAL TEXAS TUESDAY NIGHT AND WEDNESDAY... SCATTERED WRAP AROUND CLOUDS COULD IMPACT THE SOUTH CENTRAL TEXAS TAF SITES...AS MORE PREVAILING WEST TO NORTHWEST SFC WINDS DEVELOP...IN A PATTERN SIMILAR TO THE WEATHER IN MARCH. PREV DISCUSSION... /ISSUED 339 PM CDT SUN APR 1 2012/ DISCUSSION... WEAK PAIR OF SHORTWAVES WILL MAKE FOR A SLIGHT CHANCE OF THUNDERSTORMS TONIGHT INTO MONDAY...BUT LIMITED SURFACE FOCUS WILL MAKE IT DIFFICULT TO HIGHLIGHT AREAS OF CONVECTION INITIATION. ONE LIKELY AREA OVER THE BURRO MOUNTAINS HAS ALREADY YIELDED CONVECTION...BUT MODEL FORECAST WINDS SHOW STORM MOTIONS THAT WILL TAKE A LONG TIME TO REACH THE RIO GRANDE. ISOLATED POPS ARE POSTED ALONG THE RIO GRANDE WITH A FEW SHOWERS FORMING BENEATH THE CAP POSSIBLE OVER EASTERN COUNTIES LATE TONIGHT. DEEPENING LOW LEVEL MOISTURE SHOULD PROMOTE HIGHER RAIN AND THUNDERSTORM POTENTIAL DURING THE DAY MONDAY AS A LARGE UPPER LOW DRAWS CLOSER. THE APPROACHING LOW PRESSURE FROM THE WEST WILL BRING A SEVERE WEATHER POTENTIAL...BUT SOME UNCERTAINTIES ON TIMING AND LOCATION DUE TO MODELS SHOWING A SLOWING AND WOBBLING TREND. RECENT MODEL TRENDS SHOW A SLIGHTLY MORE NORTHWARD TRACK WHEN THE LOW FINALLY CROSSES TX LATE TUESDAY INTO WEDNESDAY. THIS GIVES SOUTH CENTRAL TEXAS BOTH THE POTENTIAL FOR A SEVERE WEATHER EVENT MONDAY NIGHT INTO TUESDAY AND ALSO A POTENTIAL TO BE DRY-SLOTTED...OF WHICH EITHER SCENARIO COULD BE ENHANCED BY A SUBTLE WOBBLE. WILL STICK WITH GENERIC SEVERE THREATS FOR NOW WITH BEST CHANCE OVER THE NW HALF LATE MONDAY NIGHT/EARLY TUESDAY MORNING. IF THE DRY SLOT DOES NOT SCRAPE AWAY TOO MUCH MOISTURE...A SEVERE AND POTENTIAL HEAVY RAIN EVENT COULD DEVELOP DURING THE DAY TUESDAY BEFORE THE PACIFIC FRONT PUSHES THROUGH THE I-35 CORRIDOR LATE IN THE DAY. BASED ON A SPLIT OF MODEL SOLUTIONS WILL ADD A BIT MORE COLD AND DRY AIR THAN IS SUGGESTED BY THE GFS SOLUTION WHICH MINIMIZES THE COLD FRONT AND RETURNS MOISTURE QUICKLY BY THURSDAY. WILL PUSH THE MOISTURE RETURN BACK TO FRIDAY TO ENABLE MORE SEASONAL TEMPS THURSDAY AND FRIDAY. WILL ALSO LIMIT POPS FOR THE NEXT WEATHER SYSTEM TO IMPACT THE AREA SATURDAY AND NEXT SUNDAY DUE TO THE MORE GRADUAL MOISTURE RETURN AND THE PRESENCE OF AN UPPER RIDGE OVER TX. FIRE WEATHER... A GOOD CHANCE OF WETTING RAINS COMBINED WITH NEAR OF ABOVE NORMAL RAINFALL OVER WESTERN COUNTIES THE PAST 30 DAYS SHOULD LIMIT FIRE SPREAD POTENTIAL...AS MOST AREAS HAVE NOTED A GOOD GREEN-UP OVER SOUTH CENTRAL TEXAS. THUS WILL ANTICIPATE ONLY AN ELEVATED FIRE WEATHER DAY DESPITE STRONG WEST WINDS AND CRITICAL RH VALUES NEAR THE RIO GRANDE ON TUESDAY. WILL NEED TO LOOK AT THIS AREA IN MORE DETAIL IN LATER PACKAGES IF FUTURE MODEL RUNS DECREASE THE RAIN POTENTIAL FOR THE WESTERN COUNTIES. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 69 84 67 77 60 / 10 20 40 50 20 AUSTIN BERGSTROM INTL AIRPORT 68 84 66 78 60 / 10 20 40 50 20 NEW BRAUNFELS MUNI AIRPORT 66 84 67 80 59 / 10 20 40 50 20 BURNET MUNI AIRPORT 66 83 65 77 57 / 10 20 40 50 20 DEL RIO INTL AIRPORT 67 93 64 86 58 / 10 20 40 20 - GEORGETOWN MUNI AIRPORT 66 81 65 76 58 / 10 20 40 50 20 HONDO MUNI AIRPORT 67 86 66 79 56 / 40 20 40 40 10 SAN MARCOS MUNI AIRPORT 67 84 67 79 60 / 10 20 40 50 20 LA GRANGE - FAYETTE REGIONAL 69 83 70 80 65 / 10 20 40 50 30 SAN ANTONIO INTL AIRPORT 69 84 68 79 58 / 10 20 40 40 10 STINSON MUNI AIRPORT 68 85 68 80 60 / 10 20 40 40 10 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...08 SYNOPTIC/GRIDS...25
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
249 PM CDT MON APR 2 2012 .SHORT TERM...THROUGH WEDNESDAY NIGHT 249 PM CDT MON APR 2 2012 MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES TONIGHT INTO TUESDAY. SURFACE ANALYSIS THIS AFTERNOON SHOWS AN AREA OF LOW PRESSURE OVER SOUTHEAST SOUTH DAKOTA. A WARM FRONT EXTENDED SOUTHEAST FROM THE LOW ACROSS IOWA INTO CENTRAL ILLINOIS. WATER VAPOR SATELLITE SHOWS UPPER LEVEL RIDGING REMAINS OVER THE UPPER MIDWEST TODAY. THE CONCERN FOR TONIGHT IS WHAT IS GOING TO HAPPEN TO THIS RIDGE. THE CONSENSUS OF THE 02.12Z MODELS IS THAT IT IS PRETTY MUCH GOING TO STAY IN PLACE AS IT IS BLOCKED FROM MOVING EAST BY A LONG WAVE TROUGH JUST OFF THE EAST COAST. HOWEVER...THE NORTHERN EXTENT OF THE RIDGE SHOULD GET FLATTENED SOME AS THE NORTHERN STREAM SYSTEM OVER SOUTHERN CANADA CONTINUES TO MOVE EAST PRODUCING SOME HEIGHT FALLS OVER NORTHERN MINNESOTA AND WISCONSIN. THE 02.00Z ECMWF HAS BEEN THE MOST CONSISTENT WITH THE HANDLING OF THIS SYSTEM AND THE 02.12Z NAM NOW HAS COME INTO GOOD AGREEMENT WITH THE ECMWF. AS THE SHORT WAVE TROUGH MOVES BY LATE TONIGHT...IT WILL PRODUCE THOSE MINOR HEIGHT FALLS WITH POSSIBLY UP TO 2 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER ACROSS NORTHERN WISCONSIN. THE SURFACE LOW IS EXPECTED TO EITHER TRACK ACROSS SOUTHERN MINNESOTA OR NORTHERN IOWA AS IT MOVES TOWARD NORTHERN ILLINOIS BY TUESDAY MORNING. THIS SHOULD ALLOW THE WARM FRONT TO GET LIFTED INTO THE SOUTHERN PORTIONS OF THE FORECAST AREA WITH WEAK TO MODERATE FRONTOGENESIS OCCURRING NORTH OF THE FRONT LATE TONIGHT. THE WARM AIR ADVECTION OVER THE WARM FRONT WILL PRODUCE PERSISTENT UP GLIDE OF 1 TO 4 UBAR/S ON THE 305K ISENTROPIC SURFACE. A LOT OF THIS UP GLIDE WILL INITIALLY GO INTO SATURATION AND BY THE TIME SATURATION OCCURS THE BEST UP GLIDE WILL BE MOVING OFF TO THE EAST OF THE AREA. THE WILD CARD IN WHERE THE CONVECTION WILL DEVELOP TONIGHT IS THE WARM FRONT. THE 02.12Z GFS HAS BEEN CONSISTENTLY FARTHER SOUTH WITH THE NOSE OF THE MOISTURE TRANSPORT AND LOW LEVEL JET INTO THE FRONT AROUND THE I90 CORRIDOR. THE NAM AND ECMWF INDICATE THE LOW LEVEL JET AND MOISTURE TRANSPORT WILL CONTINUE PAST THE FRONT AND CONTINUE FARTHER NORTH CLOSER TO THE SHORT WAVE TROUGH. THIS SCENARIO HAS MOST OF THE CONVECTION DEVELOPING ACROSS THE NORTHERN PARTS OF THE AREA INTO NORTHERN WISCONSIN AND THEN TRANSLATING INTO NORTHEAST AND EASTERN WISCONSIN AS THE LOW LEVEL JET BENDS OVER TO THE EAST. THE NAM SUGGESTS THERE COULD BE AROUND 750 J/KG OF ELEVATED CAPE ABOVE 2KM FOR THE STORMS TO WORK WITH. THE 0-3KM SHEAR SHOULD BE AROUND 30 TO 35 KNOTS BUT TAKING OUT THE LOWEST 1KM OF THIS SINCE THE STORMS WILL BE ELEVATED BRINGS THIS DOWN TO 15 TO 20 KNOTS. THIS IS NOT EXPECTED TO BE ENOUGH SHEAR TO ALLOW THE STORMS THAT FORM TO PRODUCE ANY SEVERE WEATHER BUT WITH PRECIPITABLE WATERS EXPECTED TO BE 200-250 PERCENT OF NORMAL...CAN NOT RULE OUT SOME LOCALIZED HEAVY RAINS. THE 02.12Z HIRES ARW AND NMM ALONG WITH THE 02.16Z HRRR ARE IN VERY GOOD AGREEMENT WITH THE NAM AND ECMWF INITIATING THE CONVECTION THIS EVENING FARTHER TO THE NORTH AS THE MOISTURE TRANSPORT OVERRUNS THE WARM FRONT. HAVE THUS MAINTAINED THE IDEA THAT THE BEST CHANCES FOR CONVECTION WILL BE ACROSS THE NORTHERN PARTS OF THE AREA AND AFTER MIDNIGHT AS THE WEAK FORCING FROM THE SHORT WAVE TROUGH APPROACHES. WILL KEEP A SMALL CHANCE OF RAIN IN THE FORECAST FOR THIS EVENING AS THE WARM FRONT APPROACHES ACROSS MOST OF THE AREA. MAINTAINED THE 30 TO 50 PERCENT CHANCES FOR AFTER MIDNIGHT TAPERING BACK TO JUST A 20 PERCENT CHANCE ACROSS THE EAST TUESDAY MORNING FOR ANY LINGERING SHOWERS. THE FRONT SHOULD BE FAR ENOUGH SOUTH TO HAVE A DRY TUESDAY AFTERNOON. AFTER THAT...HIGH PRESSURE WILL BUILD IN TO BRING SOME COOLER TEMPERATURES AND DRIER AIR. DID NOT ADD ANY FROST TO THE FORECAST FOR TUESDAY NIGHT OR WEDNESDAY NIGHT AS TEMPERATURES AND DEW POINTS ARE EXPECTED TO MAINTAIN A 5 TO 10 DEGREE SPREAD. THERE SHOULD ALSO BE SOME WINDS BOTH NIGHT TO CREATE SOME MIXING AND THE COMBINATION OF THE WINDS AND DRIER AIR SHOULD PRECLUDE FROST FORMATION. PORTIONS OF CENTRAL WISCONSIN NORTH OF THE I94 CORRIDOR COULD POSSIBLY SEE SOME FREEZING TEMPERATURES BOTH OF THESE NIGHTS. .LONG TERM...THURSDAY THROUGH MONDAY 249 PM CDT MON APR 2 2012 THE HIGH WILL REMAIN OVER THE REGION THROUGH FRIDAY MAINTAINING THE POSSIBILITY OF SOME FROST AND FREEZING TEMPERATURES AT NIGHT FOR THE END OF THE WEEK. THE HIGH WILL THEN MOVE OFF FOR THE WEEKEND AS THE NEXT SYSTEM COMES INTO THE AREA. SOME TIMING DIFFERENCES BETWEEN THE 02.12Z GFS...ECMWF AND GEM WITH THE COLD FRONT COMING ACROSS. THE ECMWF AND GEM ARE A LITTLE FASTER BUT ALL SHOW AT LEAST A CHANCE FOR SOME RAIN SATURDAY INTO SATURDAY NIGHT BEFORE IT MOVES OFF TO THE EAST FOR SUNDAY. SOME DIFFERENCES FOR NEXT MONDAY WITH THE ECMWF DROPPING ANOTHER SHORT WAVE TROUGH OVER THE AREA FOR THE POSSIBILITY OF SOME SHOWERS WHILE THE GFS IS DRY WITH HIGH PRESSURE BUILDING IN. WILL HONOR THE ECMWF WITH A SMALL RAIN CHANCE FOR MONDAY. && .AVIATION...THROUGH 18Z TUESDAY 1233 AM CDT MON APR 2 2012 MAIN FORECAST CHALLENGE IS ON CEILING HEIGHTS THROUGH THE TAF PERIOD AND CONVECTIVE POTENTIAL TONIGHT. A NARROW BAND OF VFR CLOUDS WAS PUSHING THROUGH THE KLSE TAF SITE AND SHOULD PUSH OUT BY EARLY AFTERNOON. VFR CONDITIONS THEN EXPECTED THROUGH MUCH OF THE NIGHT TONIGHT. AN AREA OF LOW PRESSURE WILL MOVE INTO NORTHERN IOWA TONIGHT. MOISTURE TRANSPORT FOCUSES INTO NORTHERN MINNESOTA THIS EVENING AND THEN NORTHERN WISCONSIN OVERNIGHT AHEAD OF THE LOW. EXPECT CONVECTION TO DEVELOP IN THESE AREAS...BUT AT THIS POINT LOOKS LIKE IT SHOULD REMAIN NORTH OF THE TAF SITES. DID ADD MENTION OF VCSH FROM 10Z-15Z DUE TO THE UNCERTAINTY. SURFACE BOUNDARY LOOKS TO MOVE THROUGH THE TAF SITES 11-12Z ACCOMPANIED BY LOWER MVFR CEILINGS...WHICH WILL PERSIST THROUGH 18Z TUESDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... 249 PM CDT MON APR 2 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1233 PM CDT MON APR 2 2012 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT 330 AM CDT MON APR 2 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THROUGH TUESDAY AND TEMPERATURES. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED RIDGING BUILDING UP ALONG THE WEST COAST OF THE U.S.... TROUGHING SPLITTING INTO TWO FROM WESTERN MONTANA INTO ARIZONA...AND STRONG RIDGING ACROSS THE ENTIRE MISSISSIPPI RIVER VALLEY NORTH INTO WESTERN HUDSON BAY. STRONG WARM ADVECTION PATTERN TAKING PLACE UNDER THE UPPER RIDGE WITH SOUTHWEST 850MB WINDS OF 30-60 KT FROM KANSAS INTO SOUTHERN MINNESOTA PER PROFILER/VWP DATA. 00Z SOUNDINGS AT MPX AND ABR SAW THEIR 850MB TEMPS RISE 3C COMPARED TO THEIR PREVIOUS 12Z ONES...NOW AT 15C AND 20C RESPECTIVELY. TIGHT THERMAL GRADIENT REMAINS...THOUGH...WITH GRB AND INL REPORTING AROUND 5C AND APX AT -1C AT 00Z. THE WARM ADVECTION ALOFT PLUS PLENTY OF DRY AIR SEEN ON THE 00Z MPX AND OAX SOUNDINGS HAS KEPT THE ATMOSPHERE CAPPED TO CONVECTION. NEAREST CONVECTION IS NEAR DULUTH INTO FAR NORTHERN WISCONSIN...ON THE NOSE OF THAT 850MB JET. BELOW THE WARM ADVECTION SEEN AT 850MB...A COOL/DRY LOW LEVEL EASTERLY FLOW CONTINUES... BETWEEN HIGH PRESSURE SITUATED OVER NORTHEAST ONTARIO AND A SURFACE WARM FRONT THAT STRETCHES FROM NEAR ABERDEEN SD TO JUST SOUTH OF DES MOINES IA AND ST LOUIS MO. AN AREA OF STRATUS LEFTOVER FROM YESTERDAY AFTERNOON IN NORTHERN ILLINOIS HAS ADVECTED ON EAST-SOUTHEAST WINDS...NOW ENCOMPASSING SOUTHWEST MINNESOTA INTO NORTH CENTRAL IOWA. TEMPERATURES SO FAR HAVE FALLEN INTO THE MID 40S TO MID 50S. SOUTH AND WEST OF THE AFOREMENTIONED WARM FRONT... READINGS ARE IN THE MID TO UPPER 60S. TODAY AND TONIGHT...WHAT LOOKED LIKE IN PREVIOUS DAYS OF 500MB HEIGHTS FALLING THROUGHOUT THIS PERIOD NOW IS COMPLETELY REVERSED. ALL MODELS NOW SHOW THE CURRENT UPPER RIDGE BUILDING OVER THE FORECAST AREA TODAY AND EVEN INTO THIS EVENING. A LOT OF THIS HAS TO DO WITH THE WESTERN TROUGH...WHICH IS SPLITTING APART EARLIER AND THE NORTHERN PORTION ONLY ENDS UP REACHING NORTHWEST MINNESOTA BY 12Z TUESDAY. THE CHANGE SYNOPTICALLY HAS A BIG IMPACT ON THE FORECAST. FIRST...NOW THAT THE AREA IS UNDERNEATH BUILDING HEIGHTS AT 500MB INDUCING SUBSIDENCE...A DRIER FORECAST IS ON TAP. HAVE REMOVED ALL PRECIPITATION CHANCES FOR TODAY AND LOWERED THEM DOWN TO AT MOST 20 FOR THIS EVENING. THE 02.00Z GFS IS BASICALLY THE ONLY MODEL THAT SHOWS PRECIPITATION TODAY...WHICH IS A RESULT OF DRIZZLE BELOW A CAP. THIS SEEMS VERY SUSPECT AND THE GFS HAS BEEN KNOWN TO OVERDO THESE DRIZZLE SCENARIOS AS SEEN BACK DURING THE UNPRECEDENTED WARM SPELL IN MARCH. RUC/NAM SOUNDINGS LOOK MORE REPRESENTATIVE. THERE STILL ARE INDICATIONS FOR PRECIPITATION AFTER 06Z TONIGHT... ESPECIALLY NORTH OF I-90 WHERE ISENTROPIC LIFT SEEN ON THE 305K SURFACE CAN INITIATE CONVECTION. NOTE...THOUGH...THE 02.00Z GEM AND 01.12Z ECMWF INITIATE THIS CONVECTION EVEN FARTHER NORTH OVER NORTHERN WISCONSIN. SINCE THE 02.00Z ECMWF LOOKS MORE LIKE THE NAM/GFS VERSUS ITS PREVIOUS RUN...HAVE LEFT THE PREVIOUS FORECAST CHANCES ALONE AFTER 06Z. IF CONVECTION GOES TONIGHT...1-6 KM SHEAR IS MOSTLY LESS THAN 15 KTS. THEREFORE...ANTICIPATING IT TO BE DISORGANIZED AND NOT PRESENT MUCH OF A SEVERE THREAT. TEMPERATURES ARE ANOTHER PROBLEM. HUDSON BAY HIGH PRESSURE LOOKS TO REMAIN ANCHORED NOW TODAY...CAUSED IN PART BY THE BUILDING UPPER RIDGING...WHICH HELPS TO MAINTAIN A FEED OF LOWER LEVEL COLD AIR SUB 850MB. FOR THE MOST PART EXPECTING HIGHS TODAY SIMILAR TO THOSE OF YESTERDAY...THOUGH COLD ADVECTION OCCURRING AT 925MB TOWARDS CENTRAL WISCONSIN COULD RESULT IN HIGHS A FEW DEGREES COLDER THERE. WITH A SLOWER PROGRESSION OF THE UPPER RIDGE...AS WELL WITH AN INVERTED SURFACE TROUGH MOVING WEST TO EAST ACROSS MINNESOTA...HAVE RAISED LOWS UP DRAMATICALLY WEST OF THE MISSISSIPPI RIVER. TUESDAY AND TUESDAY NIGHT...THE CHANGES KEEP COMING. MAJORITY OF THE ENERGY WITH THE NORTHERN PORTION OF THE WESTERN TROUGH LOOKS TO LIFT INTO NORTHEAST ONTARIO. HOWEVER...A SHORTWAVE EXTENDING SOUTHWESTWARD IS PROGGED TO MOVE INTO NORTHERN WISCONSIN BY 00Z WEDNESDAY...THEN DROP SOUTHEAST THROUGH THE AREA TUESDAY NIGHT. THIS SHORTWAVE IS IMPORTANT AS THERE APPEARS TO BE AN AREA OF LOW TO MID-LEVEL STRATUS AHEAD OF IT. ONCE THE SHORTWAVE PASSES THEN SKIES CAN CLEAR OUT. HAVE HAD TO INCREASE CLOUD COVER FOR TUESDAY TO ACCOUNT FOR THE STRATUS...WHICH IN COMBINATION WITH LOW LEVEL COLD ADVECTION HAS RESULTED IN LOWERING HIGHS FOR SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN A FEW DEGREES. ON THE OTHER HAND...THE SLOWER PROGRESSION NOTED IN THE TODAY/TONIGHT DISCUSSION WITH THE INVERTED TROUGH WILL ALLOW FAR SOUTHWEST WISCONSIN TO WARM UP MORE. WOULD NOT BE SURPRISED IF TEMPERATURES MAY TRY TO FALL IN THE WAKE OF THAT INVERTED TROUGH. REGARDING PRECIPITATION CHANCES ON TUESDAY...FORCING IS VERY WEAK GIVEN LIMITED 500MB HEIGHT FALLS AND FRONTOGENESIS BEHIND THE PASSING INVERTED TROUGH WEAKENING. IN FACT...THE 02.00Z NAM/CANADIAN BOTH SUGGEST DRY. THEREFORE...CHANCES ON TUESDAY ARE ONLY 20 PERCENT...AND CONFINED TO THE MORNING. LOWS TUESDAY NIGHT ARE KIND OF TRICKY. THE 02.00Z NAM SUGGESTS THE LOW TO MID LEVEL STRATUS REALLY DOES NOT CLEAR OUT...PARTICULARLY ALONG AND SOUTH OF I-90. HOWEVER..THE 02.00Z GFS/CANADIAN/ECMWF ARE ALL CLEARING SKIES OUT. HAVE CONSIDERED THE NAM AN OUTLIER FOR NOW AND HAVE KEPT THE PREVIOUS FORECAST AND MAJORITY CONSENSUS OF CLEARING SKIES. ANOTHER PROBLEM IS THAT THE EAST WINDS LOOK A LITTLE STRONGER BECAUSE OF THE HIGH PRESSURE AREA BUILDING IN ONLY REACHING NORTHERN MINNESOTA. IN THE END...KEPT LOWS PRETTY CLOSE TO THE PREVIOUS FORECAST. LOOKS LIKE POTENTIAL EXISTS FOR FREEZE CONDITIONS NORTH OF I-94. NO FROST ANTICIPATED...THOUGH...GIVEN DEWPOINTS EXPECTED TO FALL INTO THE 20S AND WINDS STAYING UP. WEDNESDAY AND WEDNESDAY NIGHT...A COUPLE OF BATTLING FEATURES ARE FORECAST DURING THIS PERIOD. THE SOUTHERN END OF THE CURRENT WESTERN TROUGH IS PROGGED TO CLOSE OFF INTO AN UPPER LOW...THEN LIFT THROUGH KANSAS AND MISSOURI DURING THIS PERIOD. MEANWHILE...WE HAVE THAT HIGH PRESSURE AREA BUILDING IN FROM NORTHWEST MINNESOTA...WHICH ENDS UP CONSOLIDATING WITH A CANADIAN HIGH DROPPING DOWN INTO NORTHERN ONTARIO. DRY AIR ASSOCIATED WITH THIS SURFACE HIGH PLUS UPPER RIDGING NORTH AND NORTHEAST OF THE UPPER LOW SHOULD BE SUFFICIENT TO HOLD OFF ANY PRECIPITATION FROM COMING INTO THE FORECAST AREA. COULD SEE A FEW MID/HIGH CLOUDS TRY TO APPROACH NORTHEAST IOWA...BUT ANTICIPATING MOST CLOUDS TO STAY SOUTH OF THE AREA TOO. WITH PLENTY OF SUN AND 850MB TEMPS OF 2-4C...SHOULD SEE TEMPERATURES CLIMB INTO THE LOW 60S. BETTER 925-850MB COOLING COMES IN WEDNESDAY NIGHT ON EASTERLY WINDS...LIKELY WITH THAT CANADIAN HIGH COMING DOWN. A SUSTAINED 5 TO 10 MPH WIND LOOKS LIKELY WEDNESDAY NIGHT...WHICH SHOULD HELP TEMPERATURES FROM PLUMMETING TOO MUCH. STILL...READINGS IN THE 30S ARE EXPECTED...COOLEST IN CENTRAL WISCONSIN CLOSER TO THE COLD ADVECTION. .LONG TERM...THURSDAY THROUGH SUNDAY NIGHT 330 AM CDT MON APR 2 2012 FOCUS OF THE LONG TERM FORECAST IS ON DEEP TROUGHING THAT IS ALONG THE WEST COAST THURSDAY MORNING. UPPER RIDGING DOWNSTREAM OF THE TROUGH SHOULD STAY NEAR OR OVER THE FORECAST AREA THROUGH FRIDAY EVENING...MAINTAINING DRY CONDITIONS. THURSDAY INTO THURSDAY NIGHT WILL LIKELY BE THE COOLEST PERIOD AS THE CANADIAN HIGH SLIDES DOWN INTO EASTERN WISCONSIN ON THE EAST SIDE OF THE UPPER RIDGE. IF THERE IS GOING TO BE A WIDESPREAD FREEZE...THINKING THURSDAY NIGHT WILL BE THE BEST SHOT. WISCONSIN AREAS LOOK MOST SUSCEPTIBLE BEING CLOSER TO THE SURFACE HIGH. WARMING THEN OCCURS FOR FRIDAY INTO SATURDAY AS THE SURFACE HIGH DEPARTS OFF TO THE EAST. REGARDING THE UPPER TROUGH...02.00Z ECMWF/CANADIAN/GFS AND GFS ENSEMBLES ARE ALL IN FAIRLY GOOD AGREEMENT EJECTING IT OUT INTO THE NORTHERN PLAINS ON SATURDAY. THE MODELS THEN BEGIN TO DIFFER ON SPEED FROM THERE... RESULTING IN LOWERED CONFIDENCE. IN ANY EVENT...IT APPEARS THE TROUGH HAS SLOWED DOWN ENOUGH THAT ANY FORCING FOR PRECIPITATION WILL STAY WEST OF THE FORECAST AREA FRIDAY NIGHT. MODEL CONSENSUS SUGGESTS THAT A WARM CONVEYOR BELT AHEAD OF THE NORTHERN PLAINS TROUGH WILL ENTER THE AREA SATURDAY. MEAGER INSTABILITY EXISTS... JUST ENOUGH TO WARRANT A CHANCE OF THUNDERSTORMS. AFTER SATURDAY...STAYED WITH THE MODEL CONSENSUS IDEA WHICH WOULD BE FOR A DRYING TREND. THIS IS DUE TO THE COLD FRONT ASSOCIATED WITH THE TROUGH MOVING THROUGH THE FORECAST AREA. AGAIN...LOW CONFIDENCE HERE. && .AVIATION...THROUGH 18Z TUESDAY 1233 AM CDT MON APR 2 2012 MAIN FORECAST CHALLENGE IS ON CEILING HEIGHTS THROUGH THE TAF PERIOD AND CONVECTIVE POTENTIAL TONIGHT. A NARROW BAND OF VFR CLOUDS WAS PUSHING THROUGH THE KLSE TAF SITE AND SHOULD PUSH OUT BY EARLY AFTERNOON. VFR CONDITIONS THEN EXPECTED THROUGH MUCH OF THE NIGHT TONIGHT. AN AREA OF LOW PRESSURE WILL MOVE INTO NORTHERN IOWA TONIGHT. MOISTURE TRANSPORT FOCUSES INTO NORTHERN MINNESOTA THIS EVENING AND THEN NORTHERN WISCONSIN OVERNIGHT AHEAD OF THE LOW. EXPECT CONVECTION TO DEVELOP IN THESE AREAS...BUT AT THIS POINT LOOKS LIKE IT SHOULD REMAIN NORTH OF THE TAF SITES. DID ADD MENTION OF VCSH FROM 10Z-15Z DUE TO THE UNCERTAINTY. SURFACE BOUNDARY LOOKS TO MOVE THROUGH THE TAF SITES 11-12Z ACCOMPANIED BY LOWER MVFR CEILINGS...WHICH WILL PERSIST THROUGH 18Z TUESDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... 330 AM CDT MON APR 2 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM....AJ AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
642 AM CDT MON APR 2 2012 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT 330 AM CDT MON APR 2 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THROUGH TUESDAY AND TEMPERATURES. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED RIDGING BUILDING UP ALONG THE WEST COAST OF THE U.S.... TROUGHING SPLITTING INTO TWO FROM WESTERN MONTANA INTO ARIZONA...AND STRONG RIDGING ACROSS THE ENTIRE MISSISSIPPI RIVER VALLEY NORTH INTO WESTERN HUDSON BAY. STRONG WARM ADVECTION PATTERN TAKING PLACE UNDER THE UPPER RIDGE WITH SOUTHWEST 850MB WINDS OF 30-60 KT FROM KANSAS INTO SOUTHERN MINNESOTA PER PROFILER/VWP DATA. 00Z SOUNDINGS AT MPX AND ABR SAW THEIR 850MB TEMPS RISE 3C COMPARED TO THEIR PREVIOUS 12Z ONES...NOW AT 15C AND 20C RESPECTIVELY. TIGHT THERMAL GRADIENT REMAINS...THOUGH...WITH GRB AND INL REPORTING AROUND 5C AND APX AT -1C AT 00Z. THE WARM ADVECTION ALOFT PLUS PLENTY OF DRY AIR SEEN ON THE 00Z MPX AND OAX SOUNDINGS HAS KEPT THE ATMOSPHERE CAPPED TO CONVECTION. NEAREST CONVECTION IS NEAR DULUTH INTO FAR NORTHERN WISCONSIN...ON THE NOSE OF THAT 850MB JET. BELOW THE WARM ADVECTION SEEN AT 850MB...A COOL/DRY LOW LEVEL EASTERLY FLOW CONTINUES... BETWEEN HIGH PRESSURE SITUATED OVER NORTHEAST ONTARIO AND A SURFACE WARM FRONT THAT STRETCHES FROM NEAR ABERDEEN SD TO JUST SOUTH OF DES MOINES IA AND ST LOUIS MO. AN AREA OF STRATUS LEFTOVER FROM YESTERDAY AFTERNOON IN NORTHERN ILLINOIS HAS ADVECTED ON EAST-SOUTHEAST WINDS...NOW ENCOMPASSING SOUTHWEST MINNESOTA INTO NORTH CENTRAL IOWA. TEMPERATURES SO FAR HAVE FALLEN INTO THE MID 40S TO MID 50S. SOUTH AND WEST OF THE AFOREMENTIONED WARM FRONT... READINGS ARE IN THE MID TO UPPER 60S. TODAY AND TONIGHT...WHAT LOOKED LIKE IN PREVIOUS DAYS OF 500MB HEIGHTS FALLING THROUGHOUT THIS PERIOD NOW IS COMPLETELY REVERSED. ALL MODELS NOW SHOW THE CURRENT UPPER RIDGE BUILDING OVER THE FORECAST AREA TODAY AND EVEN INTO THIS EVENING. A LOT OF THIS HAS TO DO WITH THE WESTERN TROUGH...WHICH IS SPLITTING APART EARLIER AND THE NORTHERN PORTION ONLY ENDS UP REACHING NORTHWEST MINNESOTA BY 12Z TUESDAY. THE CHANGE SYNOPTICALLY HAS A BIG IMPACT ON THE FORECAST. FIRST...NOW THAT THE AREA IS UNDERNEATH BUILDING HEIGHTS AT 500MB INDUCING SUBSIDENCE...A DRIER FORECAST IS ON TAP. HAVE REMOVED ALL PRECIPITATION CHANCES FOR TODAY AND LOWERED THEM DOWN TO AT MOST 20 FOR THIS EVENING. THE 02.00Z GFS IS BASICALLY THE ONLY MODEL THAT SHOWS PRECIPITATION TODAY...WHICH IS A RESULT OF DRIZZLE BELOW A CAP. THIS SEEMS VERY SUSPECT AND THE GFS HAS BEEN KNOWN TO OVERDO THESE DRIZZLE SCENARIOS AS SEEN BACK DURING THE UNPRECEDENTED WARM SPELL IN MARCH. RUC/NAM SOUNDINGS LOOK MORE REPRESENTATIVE. THERE STILL ARE INDICATIONS FOR PRECIPITATION AFTER 06Z TONIGHT... ESPECIALLY NORTH OF I-90 WHERE ISENTROPIC LIFT SEEN ON THE 305K SURFACE CAN INITIATE CONVECTION. NOTE...THOUGH...THE 02.00Z GEM AND 01.12Z ECMWF INITIATE THIS CONVECTION EVEN FARTHER NORTH OVER NORTHERN WISCONSIN. SINCE THE 02.00Z ECMWF LOOKS MORE LIKE THE NAM/GFS VERSUS ITS PREVIOUS RUN...HAVE LEFT THE PREVIOUS FORECAST CHANCES ALONE AFTER 06Z. IF CONVECTION GOES TONIGHT...1-6 KM SHEAR IS MOSTLY LESS THAN 15 KTS. THEREFORE...ANTICIPATING IT TO BE DISORGANIZED AND NOT PRESENT MUCH OF A SEVERE THREAT. TEMPERATURES ARE ANOTHER PROBLEM. HUDSON BAY HIGH PRESSURE LOOKS TO REMAIN ANCHORED NOW TODAY...CAUSED IN PART BY THE BUILDING UPPER RIDGING...WHICH HELPS TO MAINTAIN A FEED OF LOWER LEVEL COLD AIR SUB 850MB. FOR THE MOST PART EXPECTING HIGHS TODAY SIMILAR TO THOSE OF YESTERDAY...THOUGH COLD ADVECTION OCCURRING AT 925MB TOWARDS CENTRAL WISCONSIN COULD RESULT IN HIGHS A FEW DEGREES COLDER THERE. WITH A SLOWER PROGRESSION OF THE UPPER RIDGE...AS WELL WITH AN INVERTED SURFACE TROUGH MOVING WEST TO EAST ACROSS MINNESOTA...HAVE RAISED LOWS UP DRAMATICALLY WEST OF THE MISSISSIPPI RIVER. TUESDAY AND TUESDAY NIGHT...THE CHANGES KEEP COMING. MAJORITY OF THE ENERGY WITH THE NORTHERN PORTION OF THE WESTERN TROUGH LOOKS TO LIFT INTO NORTHEAST ONTARIO. HOWEVER...A SHORTWAVE EXTENDING SOUTHWESTWARD IS PROGGED TO MOVE INTO NORTHERN WISCONSIN BY 00Z WEDNESDAY...THEN DROP SOUTHEAST THROUGH THE AREA TUESDAY NIGHT. THIS SHORTWAVE IS IMPORTANT AS THERE APPEARS TO BE AN AREA OF LOW TO MID-LEVEL STRATUS AHEAD OF IT. ONCE THE SHORTWAVE PASSES THEN SKIES CAN CLEAR OUT. HAVE HAD TO INCREASE CLOUD COVER FOR TUESDAY TO ACCOUNT FOR THE STRATUS...WHICH IN COMBINATION WITH LOW LEVEL COLD ADVECTION HAS RESULTED IN LOWERING HIGHS FOR SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN A FEW DEGREES. ON THE OTHER HAND...THE SLOWER PROGRESSION NOTED IN THE TODAY/TONIGHT DISCUSSION WITH THE INVERTED TROUGH WILL ALLOW FAR SOUTHWEST WISCONSIN TO WARM UP MORE. WOULD NOT BE SURPRISED IF TEMPERATURES MAY TRY TO FALL IN THE WAKE OF THAT INVERTED TROUGH. REGARDING PRECIPITATION CHANCES ON TUESDAY...FORCING IS VERY WEAK GIVEN LIMITED 500MB HEIGHT FALLS AND FRONTOGENESIS BEHIND THE PASSING INVERTED TROUGH WEAKENING. IN FACT...THE 02.00Z NAM/CANADIAN BOTH SUGGEST DRY. THEREFORE...CHANCES ON TUESDAY ARE ONLY 20 PERCENT...AND CONFINED TO THE MORNING. LOWS TUESDAY NIGHT ARE KIND OF TRICKY. THE 02.00Z NAM SUGGESTS THE LOW TO MID LEVEL STRATUS REALLY DOES NOT CLEAR OUT...PARTICULARLY ALONG AND SOUTH OF I-90. HOWEVER..THE 02.00Z GFS/CANADIAN/ECMWF ARE ALL CLEARING SKIES OUT. HAVE CONSIDERED THE NAM AN OUTLIER FOR NOW AND HAVE KEPT THE PREVIOUS FORECAST AND MAJORITY CONSENSUS OF CLEARING SKIES. ANOTHER PROBLEM IS THAT THE EAST WINDS LOOK A LITTLE STRONGER BECAUSE OF THE HIGH PRESSURE AREA BUILDING IN ONLY REACHING NORTHERN MINNESOTA. IN THE END...KEPT LOWS PRETTY CLOSE TO THE PREVIOUS FORECAST. LOOKS LIKE POTENTIAL EXISTS FOR FREEZE CONDITIONS NORTH OF I-94. NO FROST ANTICIPATED...THOUGH...GIVEN DEWPOINTS EXPECTED TO FALL INTO THE 20S AND WINDS STAYING UP. WEDNESDAY AND WEDNESDAY NIGHT...A COUPLE OF BATTLING FEATURES ARE FORECAST DURING THIS PERIOD. THE SOUTHERN END OF THE CURRENT WESTERN TROUGH IS PROGGED TO CLOSE OFF INTO AN UPPER LOW...THEN LIFT THROUGH KANSAS AND MISSOURI DURING THIS PERIOD. MEANWHILE...WE HAVE THAT HIGH PRESSURE AREA BUILDING IN FROM NORTHWEST MINNESOTA...WHICH ENDS UP CONSOLIDATING WITH A CANADIAN HIGH DROPPING DOWN INTO NORTHERN ONTARIO. DRY AIR ASSOCIATED WITH THIS SURFACE HIGH PLUS UPPER RIDGING NORTH AND NORTHEAST OF THE UPPER LOW SHOULD BE SUFFICIENT TO HOLD OFF ANY PRECIPITATION FROM COMING INTO THE FORECAST AREA. COULD SEE A FEW MID/HIGH CLOUDS TRY TO APPROACH NORTHEAST IOWA...BUT ANTICIPATING MOST CLOUDS TO STAY SOUTH OF THE AREA TOO. WITH PLENTY OF SUN AND 850MB TEMPS OF 2-4C...SHOULD SEE TEMPERATURES CLIMB INTO THE LOW 60S. BETTER 925-850MB COOLING COMES IN WEDNESDAY NIGHT ON EASTERLY WINDS...LIKELY WITH THAT CANADIAN HIGH COMING DOWN. A SUSTAINED 5 TO 10 MPH WIND LOOKS LIKELY WEDNESDAY NIGHT...WHICH SHOULD HELP TEMPERATURES FROM PLUMMETING TOO MUCH. STILL...READINGS IN THE 30S ARE EXPECTED...COOLEST IN CENTRAL WISCONSIN CLOSER TO THE COLD ADVECTION. .LONG TERM...THURSDAY THROUGH SUNDAY NIGHT 330 AM CDT MON APR 2 2012 FOCUS OF THE LONG TERM FORECAST IS ON DEEP TROUGHING THAT IS ALONG THE WEST COAST THURSDAY MORNING. UPPER RIDGING DOWNSTREAM OF THE TROUGH SHOULD STAY NEAR OR OVER THE FORECAST AREA THROUGH FRIDAY EVENING...MAINTAINING DRY CONDITIONS. THURSDAY INTO THURSDAY NIGHT WILL LIKELY BE THE COOLEST PERIOD AS THE CANADIAN HIGH SLIDES DOWN INTO EASTERN WISCONSIN ON THE EAST SIDE OF THE UPPER RIDGE. IF THERE IS GOING TO BE A WIDESPREAD FREEZE...THINKING THURSDAY NIGHT WILL BE THE BEST SHOT. WISCONSIN AREAS LOOK MOST SUSCEPTIBLE BEING CLOSER TO THE SURFACE HIGH. WARMING THEN OCCURS FOR FRIDAY INTO SATURDAY AS THE SURFACE HIGH DEPARTS OFF TO THE EAST. REGARDING THE UPPER TROUGH...02.00Z ECMWF/CANADIAN/GFS AND GFS ENSEMBLES ARE ALL IN FAIRLY GOOD AGREEMENT EJECTING IT OUT INTO THE NORTHERN PLAINS ON SATURDAY. THE MODELS THEN BEGIN TO DIFFER ON SPEED FROM THERE... RESULTING IN LOWERED CONFIDENCE. IN ANY EVENT...IT APPEARS THE TROUGH HAS SLOWED DOWN ENOUGH THAT ANY FORCING FOR PRECIPITATION WILL STAY WEST OF THE FORECAST AREA FRIDAY NIGHT. MODEL CONSENSUS SUGGESTS THAT A WARM CONVEYOR BELT AHEAD OF THE NORTHERN PLAINS TROUGH WILL ENTER THE AREA SATURDAY. MEAGER INSTABILITY EXISTS... JUST ENOUGH TO WARRANT A CHANCE OF THUNDERSTORMS. AFTER SATURDAY...STAYED WITH THE MODEL CONSENSUS IDEA WHICH WOULD BE FOR A DRYING TREND. THIS IS DUE TO THE COLD FRONT ASSOCIATED WITH THE TROUGH MOVING THROUGH THE FORECAST AREA. AGAIN...LOW CONFIDENCE HERE. && .AVIATION...TODAY AND TONIGHT 641 AM CDT MON APR 2 2012 MVFR CONDITIONS CAN BE EXPECTED AT KRST EARLY THIS MORNING AS A STRATUS DECK JUST BRUSHES THE TAF SITE PRODUCING CEILINGS AROUND 2 KFT. CONDITIONS SHOULD QUICKLY IMPROVE TO VFR BY MID MORNING. VFR CONDITIONS ARE EXPECTED AT KLSE THROUGH THE AFTERNOON HOURS. A MID LEVEL CLOUD DECK WILL PRODUCE CEILINGS AROUND 6 KFT AT KLSE THROUGH 14Z...THEN SCATTERED OUT DURING THE MID TO LATE MORNING HOURS. SOUTHEAST WINDS OF 13 TO 20 KTS WILL PERSIST THROUGH THE DAY TODAY. WIND GUSTS UP TO 30 KTS ARE POSSIBLE ESPECIALLY AT KRST. A WARM FRONT CURRENTLY POSITIONED ACROSS CENTRAL IOWA...WILL LIFT NORTHWARD INTO NORTHERN IOWA/SOUTHERN WISCONSIN AS SURFACE LOW PRESSURE MOVES INTO NORTHEAST IOWA THIS AFTERNOON. LOW LEVEL MOISTURE WILL BE PUMPED NORTHWARD INTO THE REGION THIS EVENING INTO THE OVERNIGHT HOURS...LEADING TO THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. PLAN ON CEILINGS LOWERING INTO THE 3 TO 4 KFT RANGE THIS EVENING AS THE WARM FRONT MOVES IN. FORECAST MODELS SHOWING SOME DIFFERENCES ON EXACTLY WHERE THE SHOWERS AND THUNDERSTORMS WILL DEVELOP. THERE ARE SIGNALS THAT THE ACTIVITY COULD DEVELOP ALONG THE INTERSTATE 90 CORRIDOR...WHILE THERE ARE OTHERS THAT SUGGEST THE THUNDERSTORMS COULD DEVELOP ACROSS NORTHERN WISCONSIN. GIVEN THE UNCERTAINTY ON TIMING AND LOCATION OF THE THUNDERSTORMS DECIDED TO INCLUDE CB MENTION IN THE TAF...STARTING AT 08Z AT KRST AND 10Z AT KRST...WITH A FORECAST MODEL CONSENSUS OF THE THUNDERSTORMS FIRING AFTER 06Z. CHANCES FOR SHOWERS AND THUNDERSTORMS WILL PERSIST THROUGH 12 Z...BEFORE A COLD FRONT MOVES THROUGH WITH WINDS SHIFTING TO THE NORTH. && .ARX WATCHES/WARNINGS/ADVISORIES... 330 AM CDT MON APR 2 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM....AJ AVIATION.....WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
330 AM CDT MON APR 2 2012 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT 330 AM CDT MON APR 2 2012 MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THROUGH TUESDAY AND TEMPERATURES. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED RIDGING BUILDING UP ALONG THE WEST COAST OF THE U.S.... TROUGHING SPLITTING INTO TWO FROM WESTERN MONTANA INTO ARIZONA...AND STRONG RIDGING ACROSS THE ENTIRE MISSISSIPPI RIVER VALLEY NORTH INTO WESTERN HUDSON BAY. STRONG WARM ADVECTION PATTERN TAKING PLACE UNDER THE UPPER RIDGE WITH SOUTHWEST 850MB WINDS OF 30-60 KT FROM KANSAS INTO SOUTHERN MINNESOTA PER PROFILER/VWP DATA. 00Z SOUNDINGS AT MPX AND ABR SAW THEIR 850MB TEMPS RISE 3C COMPARED TO THEIR PREVIOUS 12Z ONES...NOW AT 15C AND 20C RESPECTIVELY. TIGHT THERMAL GRADIENT REMAINS...THOUGH...WITH GRB AND INL REPORTING AROUND 5C AND APX AT -1C AT 00Z. THE WARM ADVECTION ALOFT PLUS PLENTY OF DRY AIR SEEN ON THE 00Z MPX AND OAX SOUNDINGS HAS KEPT THE ATMOSPHERE CAPPED TO CONVECTION. NEAREST CONVECTION IS NEAR DULUTH INTO FAR NORTHERN WISCONSIN...ON THE NOSE OF THAT 850MB JET. BELOW THE WARM ADVECTION SEEN AT 850MB...A COOL/DRY LOW LEVEL EASTERLY FLOW CONTINUES... BETWEEN HIGH PRESSURE SITUATED OVER NORTHEAST ONTARIO AND A SURFACE WARM FRONT THAT STRETCHES FROM NEAR ABERDEEN SD TO JUST SOUTH OF DES MOINES IA AND ST LOUIS MO. AN AREA OF STRATUS LEFTOVER FROM YESTERDAY AFTERNOON IN NORTHERN ILLINOIS HAS ADVECTED ON EAST-SOUTHEAST WINDS...NOW ENCOMPASSING SOUTHWEST MINNESOTA INTO NORTH CENTRAL IOWA. TEMPERATURES SO FAR HAVE FALLEN INTO THE MID 40S TO MID 50S. SOUTH AND WEST OF THE AFOREMENTIONED WARM FRONT... READINGS ARE IN THE MID TO UPPER 60S. TODAY AND TONIGHT...WHAT LOOKED LIKE IN PREVIOUS DAYS OF 500MB HEIGHTS FALLING THROUGHOUT THIS PERIOD NOW IS COMPLETELY REVERSED. ALL MODELS NOW SHOW THE CURRENT UPPER RIDGE BUILDING OVER THE FORECAST AREA TODAY AND EVEN INTO THIS EVENING. A LOT OF THIS HAS TO DO WITH THE WESTERN TROUGH...WHICH IS SPLITTING APART EARLIER AND THE NORTHERN PORTION ONLY ENDS UP REACHING NORTHWEST MINNESOTA BY 12Z TUESDAY. THE CHANGE SYNOPTICALLY HAS A BIG IMPACT ON THE FORECAST. FIRST...NOW THAT THE AREA IS UNDERNEATH BUILDING HEIGHTS AT 500MB INDUCING SUBSIDENCE...A DRIER FORECAST IS ON TAP. HAVE REMOVED ALL PRECIPITATION CHANCES FOR TODAY AND LOWERED THEM DOWN TO AT MOST 20 FOR THIS EVENING. THE 02.00Z GFS IS BASICALLY THE ONLY MODEL THAT SHOWS PRECIPITATION TODAY...WHICH IS A RESULT OF DRIZZLE BELOW A CAP. THIS SEEMS VERY SUSPECT AND THE GFS HAS BEEN KNOWN TO OVERDO THESE DRIZZLE SCENARIOS AS SEEN BACK DURING THE UNPRECEDENTED WARM SPELL IN MARCH. RUC/NAM SOUNDINGS LOOK MORE REPRESENTATIVE. THERE STILL ARE INDICATIONS FOR PRECIPITATION AFTER 06Z TONIGHT... ESPECIALLY NORTH OF I-90 WHERE ISENTROPIC LIFT SEEN ON THE 305K SURFACE CAN INITIATE CONVECTION. NOTE...THOUGH...THE 02.00Z GEM AND 01.12Z ECMWF INITIATE THIS CONVECTION EVEN FARTHER NORTH OVER NORTHERN WISCONSIN. SINCE THE 02.00Z ECMWF LOOKS MORE LIKE THE NAM/GFS VERSUS ITS PREVIOUS RUN...HAVE LEFT THE PREVIOUS FORECAST CHANCES ALONE AFTER 06Z. IF CONVECTION GOES TONIGHT...1-6 KM SHEAR IS MOSTLY LESS THAN 15 KTS. THEREFORE...ANTICIPATING IT TO BE DISORGANIZED AND NOT PRESENT MUCH OF A SEVERE THREAT. TEMPERATURES ARE ANOTHER PROBLEM. HUDSON BAY HIGH PRESSURE LOOKS TO REMAIN ANCHORED NOW TODAY...CAUSED IN PART BY THE BUILDING UPPER RIDGING...WHICH HELPS TO MAINTAIN A FEED OF LOWER LEVEL COLD AIR SUB 850MB. FOR THE MOST PART EXPECTING HIGHS TODAY SIMILAR TO THOSE OF YESTERDAY...THOUGH COLD ADVECTION OCCURRING AT 925MB TOWARDS CENTRAL WISCONSIN COULD RESULT IN HIGHS A FEW DEGREES COLDER THERE. WITH A SLOWER PROGRESSION OF THE UPPER RIDGE...AS WELL WITH AN INVERTED SURFACE TROUGH MOVING WEST TO EAST ACROSS MINNESOTA...HAVE RAISED LOWS UP DRAMATICALLY WEST OF THE MISSISSIPPI RIVER. TUESDAY AND TUESDAY NIGHT...THE CHANGES KEEP COMING. MAJORITY OF THE ENERGY WITH THE NORTHERN PORTION OF THE WESTERN TROUGH LOOKS TO LIFT INTO NORTHEAST ONTARIO. HOWEVER...A SHORTWAVE EXTENDING SOUTHWESTWARD IS PROGGED TO MOVE INTO NORTHERN WISCONSIN BY 00Z WEDNESDAY...THEN DROP SOUTHEAST THROUGH THE AREA TUESDAY NIGHT. THIS SHORTWAVE IS IMPORTANT AS THERE APPEARS TO BE AN AREA OF LOW TO MID-LEVEL STRATUS AHEAD OF IT. ONCE THE SHORTWAVE PASSES THEN SKIES CAN CLEAR OUT. HAVE HAD TO INCREASE CLOUD COVER FOR TUESDAY TO ACCOUNT FOR THE STRATUS...WHICH IN COMBINATION WITH LOW LEVEL COLD ADVECTION HAS RESULTED IN LOWERING HIGHS FOR SOUTHEAST MINNESOTA INTO NORTH CENTRAL WISCONSIN A FEW DEGREES. ON THE OTHER HAND...THE SLOWER PROGRESSION NOTED IN THE TODAY/TONIGHT DISCUSSION WITH THE INVERTED TROUGH WILL ALLOW FAR SOUTHWEST WISCONSIN TO WARM UP MORE. WOULD NOT BE SURPRISED IF TEMPERATURES MAY TRY TO FALL IN THE WAKE OF THAT INVERTED TROUGH. REGARDING PRECIPITATION CHANCES ON TUESDAY...FORCING IS VERY WEAK GIVEN LIMITED 500MB HEIGHT FALLS AND FRONTOGENESIS BEHIND THE PASSING INVERTED TROUGH WEAKENING. IN FACT...THE 02.00Z NAM/CANADIAN BOTH SUGGEST DRY. THEREFORE...CHANCES ON TUESDAY ARE ONLY 20 PERCENT...AND CONFINED TO THE MORNING. LOWS TUESDAY NIGHT ARE KIND OF TRICKY. THE 02.00Z NAM SUGGESTS THE LOW TO MID LEVEL STRATUS REALLY DOES NOT CLEAR OUT...PARTICULARLY ALONG AND SOUTH OF I-90. HOWEVER..THE 02.00Z GFS/CANADIAN/ECMWF ARE ALL CLEARING SKIES OUT. HAVE CONSIDERED THE NAM AN OUTLIER FOR NOW AND HAVE KEPT THE PREVIOUS FORECAST AND MAJORITY CONSENSUS OF CLEARING SKIES. ANOTHER PROBLEM IS THAT THE EAST WINDS LOOK A LITTLE STRONGER BECAUSE OF THE HIGH PRESSURE AREA BUILDING IN ONLY REACHING NORTHERN MINNESOTA. IN THE END...KEPT LOWS PRETTY CLOSE TO THE PREVIOUS FORECAST. LOOKS LIKE POTENTIAL EXISTS FOR FREEZE CONDITIONS NORTH OF I-94. NO FROST ANTICIPATED...THOUGH...GIVEN DEWPOINTS EXPECTED TO FALL INTO THE 20S AND WINDS STAYING UP. WEDNESDAY AND WEDNESDAY NIGHT...A COUPLE OF BATTLING FEATURES ARE FORECAST DURING THIS PERIOD. THE SOUTHERN END OF THE CURRENT WESTERN TROUGH IS PROGGED TO CLOSE OFF INTO AN UPPER LOW...THEN LIFT THROUGH KANSAS AND MISSOURI DURING THIS PERIOD. MEANWHILE...WE HAVE THAT HIGH PRESSURE AREA BUILDING IN FROM NORTHWEST MINNESOTA...WHICH ENDS UP CONSOLIDATING WITH A CANADIAN HIGH DROPPING DOWN INTO NORTHERN ONTARIO. DRY AIR ASSOCIATED WITH THIS SURFACE HIGH PLUS UPPER RIDGING NORTH AND NORTHEAST OF THE UPPER LOW SHOULD BE SUFFICIENT TO HOLD OFF ANY PRECIPITATION FROM COMING INTO THE FORECAST AREA. COULD SEE A FEW MID/HIGH CLOUDS TRY TO APPROACH NORTHEAST IOWA...BUT ANTICIPATING MOST CLOUDS TO STAY SOUTH OF THE AREA TOO. WITH PLENTY OF SUN AND 850MB TEMPS OF 2-4C...SHOULD SEE TEMPERATURES CLIMB INTO THE LOW 60S. BETTER 925-850MB COOLING COMES IN WEDNESDAY NIGHT ON EASTERLY WINDS...LIKELY WITH THAT CANADIAN HIGH COMING DOWN. A SUSTAINED 5 TO 10 MPH WIND LOOKS LIKELY WEDNESDAY NIGHT...WHICH SHOULD HELP TEMPERATURES FROM PLUMMETING TOO MUCH. STILL...READINGS IN THE 30S ARE EXPECTED...COOLEST IN CENTRAL WISCONSIN CLOSER TO THE COLD ADVECTION. .LONG TERM...THURSDAY THROUGH SUNDAY NIGHT 330 AM CDT MON APR 2 2012 FOCUS OF THE LONG TERM FORECAST IS ON DEEP TROUGHING THAT IS ALONG THE WEST COAST THURSDAY MORNING. UPPER RIDGING DOWNSTREAM OF THE TROUGH SHOULD STAY NEAR OR OVER THE FORECAST AREA THROUGH FRIDAY EVENING...MAINTAINING DRY CONDITIONS. THURSDAY INTO THURSDAY NIGHT WILL LIKELY BE THE COOLEST PERIOD AS THE CANADIAN HIGH SLIDES DOWN INTO EASTERN WISCONSIN ON THE EAST SIDE OF THE UPPER RIDGE. IF THERE IS GOING TO BE A WIDESPREAD FREEZE...THINKING THURSDAY NIGHT WILL BE THE BEST SHOT. WISCONSIN AREAS LOOK MOST SUSCEPTIBLE BEING CLOSER TO THE SURFACE HIGH. WARMING THEN OCCURS FOR FRIDAY INTO SATURDAY AS THE SURFACE HIGH DEPARTS OFF TO THE EAST. REGARDING THE UPPER TROUGH...02.00Z ECMWF/CANADIAN/GFS AND GFS ENSEMBLES ARE ALL IN FAIRLY GOOD AGREEMENT EJECTING IT OUT INTO THE NORTHERN PLAINS ON SATURDAY. THE MODELS THEN BEGIN TO DIFFER ON SPEED FROM THERE... RESULTING IN LOWERED CONFIDENCE. IN ANY EVENT...IT APPEARS THE TROUGH HAS SLOWED DOWN ENOUGH THAT ANY FORCING FOR PRECIPITATION WILL STAY WEST OF THE FORECAST AREA FRIDAY NIGHT. MODEL CONSENSUS SUGGESTS THAT A WARM CONVEYOR BELT AHEAD OF THE NORTHERN PLAINS TROUGH WILL ENTER THE AREA SATURDAY. MEAGER INSTABILITY EXISTS... JUST ENOUGH TO WARRANT A CHANCE OF THUNDERSTORMS. AFTER SATURDAY...STAYED WITH THE MODEL CONSENSUS IDEA WHICH WOULD BE FOR A DRYING TREND. THIS IS DUE TO THE COLD FRONT ASSOCIATED WITH THE TROUGH MOVING THROUGH THE FORECAST AREA. AGAIN...LOW CONFIDENCE HERE. && .AVIATION...THROUGH 06Z TUESDAY 1149 PM CDT SUN APR 1 2012 WARM FRONT CURRENTLY RESIDES ACROSS IOWA...WITH BROAD EASTERLY FLOW TO ITS NORTH OVER THE TAF SITES. SMALL BAND OF STRATUS WAS SEEN FROM EASTERN IOWA INTO NORTH CENTRAL IOWA...JUST NORTH OF THE WARM FRONT. 02.02Z RUC 925MB RELATIVE HUMIDITY FIELD DEPICTS THE LOCATION ACCURATELY...BUT IS OVERDONE WITH THE SPATIAL COVERAGE. TRENDS IN BOTH THE NAM AND RUC SHOW THIS MOISTURE TO CONTINUE TO ADVECT NORTHWEST INTO SOUTHERN MINNESOTA THROUGH 12Z. IT LOOKS AS THOUGH THIS WILL JUST MISS THE KRST TAF SITE...BUT DID CONTINUE TO INCLUDE SOME SCATTERED STRATUS BETWEEN 08Z-16Z. EASTERLY FLOW WILL CONTINUE THROUGHOUT THE REMAINDER OF THE PERIOD WITH THE PRESSURE GRADIENT TIGHTENING MONDAY MORNING. COULD SEE SOME GUSTS TO 20 TO 25 KNOTS AT KRST BETWEEN 16Z-22Z...WITH SLIGHTLY LOWER GUSTS AT KLSE. ALSO EXPECT VFR CEILINGS TO FORM WITH A BKN040-050KFT DECK EXPECTED FROM 16Z ON. SURFACE LOW MOVES INTO IOWA BETWEEN 00Z-06Z MONDAY. ANY CONVECTION THAT FIRES IS EXPECTED TO BE NORTH AND WEST OF THE TAF SITES THROUGH 06Z THOUGH. && .ARX WATCHES/WARNINGS/ADVISORIES... 330 AM CDT MON APR 2 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1149 PM CDT SUN APR 1 2012 .SHORT TERM...THROUGH TUESDAY NIGHT 303 PM CDT SUN APR 1 2012 MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES MONDAY THROUGH TUESDAY. SURFACE ANALYSIS THIS AFTERNOON SHOWS AN AREA OF LOW PRESSURE OVER WESTERN NORTH AND SOUTH DAKOTA. A WARM FRONT EXTENDS SOUTHEAST FROM THE LOW INTO CENTRAL ILLINOIS. WATER VAPOR SATELLITE SHOWS UPPER LEVEL RIDGING OVER THE UPPER MIDWEST TODAY AS THE NEXT STORM SYSTEM IS WORKING ACROSS THE ROCKY MOUNTAINS. MODELS CONTINUE TO BE CONSISTENT IS SHOWING THE ENERGY IN THE TROUGH SPLITTING INTO A PROGRESSIVE NORTHERN STREAM SYSTEM AND A CUT OFF SOUTHERN STREAM UPPER LEVEL LOW. THE SPLIT OF THE ENERGY HAS ALREADY STARTED AND WILL CONTINUE THROUGH THE NIGHT. THE MODELS ALSO HAVE CONTINUED THEIR TREND OF BEING SLOWER PUSHING THE UPPER LEVEL RIDGE OUT OF THE AREA AND NOW SUGGEST THIS MAY NOT OCCUR UNTIL MONDAY NIGHT. THERE ALSO IS THE SUGGESTION THAT THE NORTHERN STREAM SHORT WAVE TROUGH MAY BE A LITTLE BIT STRONGER THAN PREVIOUSLY INDICATED BUT THE BULK OF THE FORCING FROM THIS WAVE WILL STILL PASS BY TO THE NORTH. THE 01.12Z GFS ONLY SUGGEST AROUND 4 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER COULD POSSIBLY MOVE ACROSS NORTHERN WISCONSIN TUESDAY. AS THE WHOLE SYSTEM ADVANCES EAST...THE SURFACE LOW IS EXPECTED TO REFORM OVER NEBRASKA AND THEN MOVE EAST/NORTHEAST ALONG A COLD FRONT. AS THE FRONT COMES THROUGH...WEAK FRONTOGENESIS SHOULD OCCUR ACROSS MINNESOTA AND WISCONSIN CLOSER TO THE UPPER LEVEL SUPPORT. A BROAD AREA OF WARM AIR ADVECTION WILL OCCUR AHEAD OF THE COLD FRONT WHICH RESULTS IN 1 TO 3 UBARS/S OF UP GLIDE ON THE 305K ISENTROPIC SURFACE FOR MONDAY AND MONDAY NIGHT. WITH THE SLOWER ARRIVAL OF THE FORCING...REMOVED THE RAIN CHANCES FOR MONDAY MORNING AND LIMITED THEM TO THE FAR NORTHWEST SECTIONS OF THE FORECAST AREA MONDAY AFTERNOON. THE BETTER FORCING THEN ARRIVES MONDAY NIGHT AHEAD OF THE SHORT WAVE TROUGH WITH THE BEST CHANCES FOR RAIN ACROSS THE NORTH CLOSER TO WHERE THE PV ADVECTION WILL BE. NO CHANGES MADE TO THE MONDAY NIGHT FORECAST WITH UP TO A 50 PERCENT CHANCE ACROSS THE NORTH. ADDED IN SOME 20 TO 30 PERCENT RAIN CHANCES FOR TUESDAY MORNING ACROSS THE SOUTHEAST TO ACCOUNT FOR THE SLOWER MOVEMENT OF THE SYSTEM AND THE POSSIBILITY OF SOME LINGERING SHOWERS. REMAIN CONCERNED THAT THE FORECAST REMAINS TOO FAST BRINGING THIS SYSTEM INTO THE AREA AS THE ECMWF HAS CONSISTENTLY BEEN SLOWER THAN EITHER THE NAM OR GFS. THE 31.00Z AND 04.12Z RUNS OF ECMWF CONTINUE THIS TREND AND IF THIS SLOWER SOLUTION VERIFIES...WOULD NOT BE SURPRISED TO SEE THE ENTIRE AREA REMAINS DRY MONDAY WITH WARMER TEMPERATURES AS THE WARM AIR OVER IOWA...NEBRASKA AND MISSOURI GETS DRAWN INTO THE REGION AHEAD OF THE COLD FRONT. THIS COULD ALSO LEAD TO NEEDING RAIN CHANCES FARTHER WEST TUESDAY MORNING POSSIBLY LINGERING INTO THE AFTERNOON ACROSS THE SOUTHEAST. .LONG TERM...WEDNESDAY THROUGH SUNDAY 303 PM CDT SUN APR 1 2012 ONCE THE EARLY WEEK SYSTEM MOVES THROUGH...HIGH PRESSURE IS EXPECTED TO SETTLE IN OVER THE REGION FOR THE REMAINDER OF THE WORK WEEK. THIS HIGH WILL BRING THE POTENTIAL FOR CENTRAL WISCONSIN TO POSSIBLY DIP INTO THE LOWER TO MIDDLE 30S SETTING UP THE POTENTIAL FOR SOME FREEZING CONDITIONS OR FROST FORMATION. ONCE THE HIGH MOVES OFF...THE NEXT SYSTEM WILL APPROACH FOR THE WEEKEND. THERE CONTINUES TO BE A TREND OF SLOWING THIS SYSTEM DOWN AND MOST OF THE AREA SHOULD REMAIN DRY FRIDAY NIGHT BEFORE THE COLD FRONT MOVES IN WITH SOME RAIN CHANCES FOR SATURDAY AND SATURDAY NIGHT. && .AVIATION...THROUGH 06Z TUESDAY 1149 PM CDT SUN APR 1 2012 WARM FRONT CURRENTLY RESIDES ACROSS IOWA...WITH BROAD EASTERLY FLOW TO ITS NORTH OVER THE TAF SITES. SMALL BAND OF STRATUS WAS SEEN FROM EASTERN IOWA INTO NORTH CENTRAL IOWA...JUST NORTH OF THE WARM FRONT. 02.02Z RUC 925MB RELATIVE HUMIDITY FIELD DEPICTS THE LOCATION ACCURATELY...BUT IS OVERDONE WITH THE SPATIAL COVERAGE. TRENDS IN BOTH THE NAM AND RUC SHOW THIS MOISTURE TO CONTINUE TO ADVECT NORTHWEST INTO SOUTHERN MINNESOTA THROUGH 12Z. IT LOOKS AS THOUGH THIS WILL JUST MISS THE KRST TAF SITE...BUT DID CONTINUE TO INCLUDE SOME SCATTERED STRATUS BETWEEN 08Z-16Z. EASTERLY FLOW WILL CONTINUE THROUGHOUT THE REMAINDER OF THE PERIOD WITH THE PRESSURE GRADIENT TIGHTENING MONDAY MORNING. COULD SEE SOME GUSTS TO 20 TO 25 KNOTS AT KRST BETWEEN 16Z-22Z...WITH SLIGHTLY LOWER GUSTS AT KLSE. ALSO EXPECT VFR CEILINGS TO FORM WITH A BKN040-050KFT DECK EXPECTED FROM 16Z ON. SURFACE LOW MOVES INTO IOWA BETWEEN 00Z-06Z MONDAY. ANY CONVECTION THAT FIRES IS EXPECTED TO BE NORTH AND WEST OF THE TAF SITES THROUGH 06Z THOUGH. && .ARX WATCHES/WARNINGS/ADVISORIES... 303 PM CDT SUN APR 1 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS MIAMI FL
448 AM EDT WED APR 4 2012 ...FEW STRONG THUNDERSTORMS POSSIBLE THIS AFTERNOON, THU AFTERNOON, AND FRIDAY WITH LOW PROBABILITIES OF SEVERE... ...HOT THROUGH FRIDAY, THEN COOLER AND DRIER THIS WEEKEND-NEXT WEEK... .DISCUSSION...WATER VAPOR IMAGERY SHOWS A MID/UPPER LEVEL LOW SPINNING OVER THE TEXAS/OKLAHOMA PANHANDLE REGION WITH WEST SOUTHWEST FLOW PREDOMINATING ACROSS THE GULF AND ACROSS FLORIDA. BOTH GFS AND ECMWF SHOW THIS UPPER LOW MOVING ACROSS THIS MID SOUTH ON THU...THEN OPENING UP AND MERGING WITH A TROUGH WHICH WILL AMPLIFY ACROSS NEW ENGLAND AND THE MID ATLANTIC STATES ON FRIDAY. LOW PRESSURE WILL DEVELOP NEAR THE CAROLINA COAST MOVING INTO THE ATLANTIC FRIDAY WITH A TRAILING COLD FRONT SWEEPING ACROSS SOUTH FLORIDA FRIDAY EVENING. AHEAD OF THIS FRONT, THE AIRMASS WILL CONTINUE FAIRLY DRY WITH FORECAST SOUNDINGS SHOWING PWAT VALUES OF 1-1.2 INCHES TODAY RISING TO 1.3-1.5 LATE THU-FRI. IT WILL BE UNSTABLE EACH AFTERNOON THROUGH FRIDAY. GOES SOUNDER DATA SHOWS H5 TEMPS NOW IN THE -12 TO -13C RANGE OVER SOUTH FLORIDA. FCST SOUNDINGS SHOW EVEN SLIGHT COOLING TO -14C BY EVENING WITH LI`S FALLING TO AROUND -7C AND CAPE NEARING 2000 J/KG LATE IN THE DAY. GIVEN LACK OF MOISTURE...ONLY HAVE SLIGHT CHC POPS INTERIOR-EAST. IT`S POSSIBLE THAT NOTHING DEVELOPS THIS AFTERNOON...BUT THERE MAY BE JUST ENOUGH MOISTURE TO ALLOW A FEW TSTORMS TO DEVELOP. HRRR INDEED DOES SHOW ISOLATED DEVELOPMENT INTERIOR/EAST COAST THIS AFTERNOON. GIVEN THE STRONG HEATING TODAY AND COLD AIR ALOFT, ONE OR TWO PULSE STRONG TSTORMS WILL BE POSSIBLE INTERIOR-EAST, CAPABLE OF PRODUCING GUSTY WINDS UP TO 50 MPH ALONG WITH HAIL AND FREQUENT LIGHTNING STRIKES. AS MOISTURE INCREASES A TAD THURSDAY AFTERNOON, THE RISK OF TSTORMS INCREASES. SW STEERING FLOW WILL LEAD TO CONVERGENCE ACROSS THE EAST COAST METRO AREAS, SO SCATTERED TSTORMS ARE EXPECTED EAST COAST METRO WITH A SLIGHT CHANCE ELSEWHERE. THEN ON FRIDAY THERE WILL BE A CHANCE OF THUNDERSTORMS AREA WIDE ALONG/AHEAD OF THE COLD FRONT. STABILITY INDICES SHOW THAT IT WILL CONTINUE TO BE QUIET UNSTABLE, PARTICULARLY ON THURSDAY AFTERNOON. HOWEVER, THE BETTER DYNAMICS WILL BE ON FRIDAY. STRONG TSTORMS WILL BE POSSIBLE EACH DAY WITH LOW PROBABILITIES OF SEVERE. CURRENT ASSESSMENT SUGGESTS THAT THE GREATEST POTENTIAL FOR ISOLATED SEVERE THUNDERSTORMS IS THURSDAY AFTERNOON EAST COAST METRO...DUE TO WEAKER FLOW ON THIS DAY, BETTER SURFACE CONVERGENCE AND HIGH INSTABILITY. HOT DAYS WILL PREVAIL THROUGH FRIDAY WITH HIGHS TOPPING 90 MOST INLAND LOCALES AND NEAR 90 EAST. CONSENSUS GUIDANCE WAS TOO COOL FOR MAXES NEXT FEW DAYS...SO FOLLOWED A NAM12-GFS BLEND. THE COLD FRONT WILL MOVE ACROSS SOUTH FL FRIDAY EVENING, BRINGING IN A COOL AIRMASS FOR APRIL STANDARDS WITH HIGHS IN THE UPPER 70S TO LOWER 80S AND DEWPOINTS FALLING INTO THE 50S THIS WEEKEND. NIGHTTIME LOWS WILL FALL INTO THE 50S INTERIOR AND 60S COASTS. THIS COOLER TREND WILL CONTINUE NEXT WEEK...WITH BOTH GFS/ECMWF SHOWING A RE- ENFORCING SHOT OF COOLER AIR FROM THE NORTH MID WEEK. THIS WILL KEEP TEMPS/HUMIDITY IN CHECK THROUGH NEXT WEEK WITH COMFORTABLE WEATHER PREVAILING AND DRY WEATHER EXPECTED. && .MARINE...NO CONCERNS IN THE NEAR TERM, BUT WINDS/SEAS WILL INCREASE, ESPECIALLY IN THE GULF STREAM BEHIND THE COLD FRONT FRI EVENING AS WINDS BECOME NE AND INCREASE. && .FIRE WEATHER...RELATIVE HUMIDITIES FELL INTO THE MID 20S TO LOWER 30S OVER A LARGE PORTION OF INTERIOR SOUTH FL YESTERDAY. TODAY, LOW RH`S OF BELOW 35 PERCENT FOR 4 HR OR MORE ARE FORECAST FOR THE LAKE OKEECHOBEE REGION AND INLAND COLLIER AND INLAND BROWARD COUNTIES...SO WILL BE ISSUING A FIRE DANGER STMT FOR THESE LOCALES. MOISTURE WILL INCREASE ON THU-FRI WITH MODIFYING RH`S THEN. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 71 89 72 / 20 10 40 40 FORT LAUDERDALE 88 72 89 73 / 10 10 30 30 MIAMI 88 72 89 73 / 10 10 30 30 NAPLES 85 69 85 71 / - 10 20 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...57/GREGORIA AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
340 AM EDT WED APR 4 2012 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 340 AM EDT WED APR 4 2012 07Z SFC ANALYSIS SHOWS A LOW CENTERED OVER SOUTHERN MISSOURI WITH A WEST TO EAST WARM FRONT/ELONGATED AREA OF LOWER PRESSURE RUNNING GENERALLY ALONG THE OHIO RIVER. THIS BOUNDARY HAS REMAINED INTERMITTENTLY ACTIVE THROUGH THE NIGHT...EVEN AS THE MORE ROBUST... DIURNALLY DRIVEN...SLOW MOVING CONVECTION DIED OUT OVER EAST KENTUCKY DURING THE LATE EVENING. DO EXPECT THAT THIS REGION OF LOWER PRESSURE WILL BECOME MORE ACTIVE TOWARD DAWN IN CONJUNCTION WITH A SLOW MOVING BAND OF MID LEVEL SHORTWAVES RUNNING THROUGH THE SOUTHERN OHIO VALLEY. THE ENVIRONMENT IS RELATIVELY MOIST OVER THE AREA WITH DEWPOINTS RUNNING IN THE MID AND UPPER 50S WHILE TEMPERATURES ARE SETTLING INTO THE LOWER 60S IN MOST PLACES...EARLY THIS MORNING. THE MODELS ARE IN DECENT AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST AS THEY ALL ROLL A CLOSED AND SOMEWHAT CUT OFF LOW THROUGH THE SOUTHERN PLAINS AND TOWARDS THE LOWER OHIO VALLEY BY THURSDAY MORNING. FLAT RIDGING AND DEEP SOUTHWEST FLOW EXIST OUT AHEAD OF THIS LOW AFFECTING KENTUCKY AND THIS WILL BE SQUEEZED OFF TO THE EAST BY 12Z THURSDAY. AT THE SAME TIME...A DEEP TROUGH OVER THE NORTHEAST WILL SHIFT SLIGHTLY SOUTH. GIVEN THE MODEL SIMILARITIES ALOFT HAVE GONE WITH A BLENDED SOLUTION WITH A LEAN TOWARD THE HIGHER RESOLUTION NAM12...AND A NOD TO THE HRRR IN THE NEAR TERM... BUT TRANSLATED SLIGHTLY SOUTH IN LINE WITH THE OTHER MODELS LATTER IN THE SHORT TERM. AN ACTIVE WEATHER PERIOD IS UPON US WITH THE APPROACH OF THE UPPER LOW TO THE WEST AND THE STALLED BOUNDARY LAYING OVER NORTRHERN PARTS OF EAST KENTUCKY. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP AND INCREASE THROUGH THE AREA LATER TODAY AS DIURNAL HEATING INITIATES CONVECTION...HELPED ALONG BY SFC CONVERGENCE WITH THE BOUNDARY AND SOME UPPER LEVEL DIVERGENCE. THE STEAMY BOUNDARY LAYER WILL CONTRIBUTE TO HIGH INSTABILITY TODAY WITH MID LEVEL WINDS FAVORABLE FOR MORE ORGANIZED CONVECTION. AS A RESULT...STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE THROUGH THE AREA WITH HIGH PW AIR SETTING THE STAGE FOR HEAVY RAIN FROM ANY HEALTHY STORMS. DAMAGING WINDS AND LARGE HAIL WILL BE THE MAIN THREAT FROM THESE. THE STORMS WILL BE MORE PROGRESSIVE THAN YESTERDAY...BUT TRAINING...AND PLENTY OF AREAS OF LOWER FFG AFTER YESTERDAY/S RAINS...WILL MAKE FLASH FLOODING A CONCERN LATER TODAY AND THROUGH THE FIRST PART OF THE NIGHT. ACCORDINGLY...WILL HOIST A FLASH FLOOD WATCH FOR ALL BUT OUR NORTHWEST COUNTIES. THE HEAVIER RAINS WILL DISSIPATE BY THURSDAY MORNING AS DRIER AIR SEEPS INTO THE REGION FROM THE NORTH...BUT THE THREAT OF SHOWERS AND THUNDERSTORMS WILL REMAIN THROUGH THE DAY. THE BAROCLINIC ZONE IN PLACE THROUGH THE AREA ON THURSDAY WILL KEEP THE NORTHERN COUNTIES UP TO 10 DEGREES COOLER THAN THE SOUTHERN ONES FOR HIGHS THURSDAY. HAVE FOLLOWED A BLEND OF THE MOS GUIDANCE THROUGH THE PERIOD ALLOWING THE MAV NUMBERS TO TEMPER THE MET/S...WITH LITTLE IN THE WAY OF TERRAIN ADJUSTMENTS GIVEN THE MOIST ENVIRONMENT. DID FAVOR THE MET POPS THROUGH THE SHORT TERM...BUT HAD THEM TRANSLATED MORE TO THE SOUTH OWING TO THE CONSENSUS FAVORING MORE SUPPRESSION OF THE FRONTAL BOUNDARY FROM THE HIGH TO THE NORTHEAST. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 305 AM EDT WED APR 4 2012 THE MODELS ARE IN GOOD AGREEMENT REGARDING THE EVOLUTION OF WEATHER SYSTEMS FOR THE DAY 4-7 PERIOD. INITIALLY...SCATTERED RAIN SHOWERS WILL BE PRESENT FROM THE TENNESSEE BORDER NORTHWARD TO THE HAL ROGERS PARKWAY AND ALONG AND NORTH OF THE HIGHWAY 80 CORRIDOR. THESE RAIN SHOWERS WILL LIKELY LINGER THROUGH 9 OR 10Z ACROSS THIS AREA ON FRIDAY MORNING...BEFORE EXITING INTO VIRGINIA BY 13Z OR SO. AFTER THAT...THE MODELS ALL AGREE THAT HIGH PRESSURE WILL BECOME FIRMLY ESTABLISHED ACROSS THE OHIO AND TENNESSEE VALLEY AREAS THROUGH SUNDAY MORNING. THE GFS AND ECMWF BOTH ARE QUICKLY MOVING A WEAK FRONTAL BOUNDARY AND UPPER LEVEL TROUGH ACROSS THE REGION ON SUNDAY. THESE FEATURES WILL JUST STRONG ENOUGH AND HAVE JUST ENOUGH MOISTURE ASSOCIATED WITH THEM TO SPARK ISOLATED TO SCATTERED RAIN SHOWERS. AT THIS TIME THE MODEL DATA INDICATE THAT THE ATMOSPHERE WILL ONLY BE ABLE TO SUPPORT ISOLATED THUNDERSTORM ACTIVITY. WITH ALL THAT IN MIND...THE INHERITED FORECAST FOR SUNDAY WAS ADJUSTED TO REFLECT PRECIPITATION CHANCE THAT WERE A GOOD DEAL LOWER...AND MORE IN LINE WITH THE LATEST MEXMOS DATA...WHICH WAS REFLECTIVE OF 20-30 PERCENT PRECIPITATION PROBABILITIES ACROSS THE BOARD. ANOTHER AREA OF WEAK HIGH PRESSURE WILL THEN BECOME ESTABLISHED ACROSS THE SUNDAY NIGHT AND MONDAY. ANOTHER EVEN MORE ILL DEFINED FRONTAL BOUNDARY AND UPPER TROUGH COMBO WILL BRING SCATTERED RAIN SHOWERS TO EASTERN KENTUCKY MONDAY NIGHT AND TUESDAY. THE WEATHER...SKY COVER...AND PRECIPITATION AMOUNT FORECASTS WERE ALL ADJUSTED BASED ON THE LOWER PRECIPITATION PROBABILITIES. ACCOUNTING FOR THE AMOUNT OF CLOUD COVER AND PRECIPITATION EXPECTED...AND WITH SOMEWHAT COOLER AIR MASSES EXPECTED TO MOVE ACROSS THE AREA...TEMPERATURES WILL BE VERY CLOSE TO NORMAL THROUGH MONDAY...AND MAY EVEN BE SEVERAL DEGREES BELOW NORMAL NEXT TUESDAY AS COOLER AIR MAKES A FAIRLY DEEP SOUTHWARD INTRUSION INTO THE EASTERN CONUS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 235 AM EDT WED APR 4 2012 WITH THE WARM FRONT LYING ACROSS THE AREA...CONVECTION IS POSSIBLE AT ALMOST ANYTIME AND ANYWHERE THROUGHOUT EAST KENTUCKY. DO EXPECT THE ACTIVITY TO BE AT A MINIMUM THROUGH DAWN FOR MOST PLACES...EXCEPT AN UPTICK IN THE NORTH TOWARD 12Z IN RELATION TO A PASSING SHORT WAVE. OTHERWISE...WILL LET THE DIURNAL CYCLE DRIVE THE DEVELOPMENT AND EXPANSION OF SHOWERS AND THUNDERSTORMS THROUGH THE AREA THIS AFTERNOON AND INTO THE EVENING. WITH THIS...HAVE ADDED VCTS INTO THE TAFS AFTER 09Z AND A TEMPO FOR MVFR CONDITIONS IN ANY STORMS FOR THAT PERIOD AROUND DAWN. FOLLOWING THIS...ANTICIPATE A LULL IN THE ACTIVITY UNTIL MIDDAY FOR MOST OF THE AREA AND THEN CONVECTION BLOSSOMING AGAIN FROM LATE AFTERNOON AND WELL INTO THE EVENING. ANY STORM WILL BRING WITH IT MVFR CIGS AND VIS DOWN TO IFR OR LESS IN HEAVY RAIN. WINDS THROUGH THE PERIOD WILL BE GENERALLY FROM THE WEST AT 5 TO 10 KTS THROUGH THE PERIOD...THOUGH HIGHER IN AND AROUND ANY STORMS. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR KYZ058>060-068-069-079-080-083>088-104-106>120. && $$ SHORT TERM...GREIF LONG TERM....AR AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
300 AM MDT WED APR 4 2012 .DISCUSSION...WRAP AROUND/JET RELATED PRECIPITATION CONTINUING OVER EASTERN HALF OF NEW MEXICO ATTM. LATEST RUC SHOWS UPPER LOW WILL MOVE VERY SLOWLY THIS MORNING...CENTERED OVER THE NORTHERN TX PANHANDLE BY NOON. RAIN WAS INDICATED TO BE THE PREDOMINANT PRECIPITATION TYPE WITH THE WEST TO EAST ORIENTED BAND STRETCHING ACROSS LINCOLN COUNTY TO NEAR MILNESAND. WITH TEMPS NEAR FREEZING...SNOW WAS ASSOCIATED WITH THE WRAP AROUND ECHOES FROM ANGEL FIRE TO RATON AND CLAYTON. EXPECT MINIMAL ACCUMULATIONS AND IMPACTS WITH THIS...AS COMPARED TO THE LAST 36 HOURS. OTHERWISE...AREAS OF LOW CLOUDS AND FOG WILL PLAGUE THE RIO GRANDE VALLEY EASTWARD THIS MORNING. THE LINGERING PRECIPITATION SHOULD BE OVER WITH BY THIS AFTERNOON. HIGH TEMPERATURES WILL BE WARMER OVERALL TODAY...AND ALTHOUGH THE SURFACE GRADIENT ISN/T VERY STRONG COULD NOT RULE OUT SOME NORTHWEST TO NORTHERLY BREEZES IN THE EAST...BUT ESPECIALLY NEAR THE TEXAS BORDER WHERE FORECAST H7 WINDS ARE AROUND 30KT. MODELS INDICATE HIGH LEVEL MOISTURE INCREASING TONIGHT ...MAYBE ENOUGH TO KEEP FOG FROM DEVELOPING OVER AREAS WHICH RECEIVED SIGNIFICANT SNOWFALL MONDAY NIGHT/TUESDAY. CONFIDENCE NOT THAT GREAT BUT WENT AHEAD AND PUT PATCHY FOG IN THE GRIDS FOR THE SANGRE DE CRISTO MOUNTAINS/NORTHEAST HIGHLANDS AND OVER TOWARDS CAPULIN/FOLSOM...WHERE MELTING SHOULD CONTINUE DURING THE DAY TODAY. THURSDAY AND FRIDAY FEATURE A WARMING TREND WITH TEMPERATURES BACK ABOVE NORMAL. INCREASING SOUTHWEST FLOW ALOFT IS ANTICIPATED AS A SYSTEM PASSES THROUGH THE NORTHERN ROCKIES. THIS IS MUCH FARTHER NORTH THAN SHOWN A COUPLE OF DAYS AGO...SO WINDS SHOULDN/T GET TOO UNRULY. A SURFACE FRONT DROPPING INTO THE PLAINS ON SATURDAY APPEARS TO BE ENOUGH OF A MECHANISM TO IGNITE A FEW THUNDERSTORMS BUT INITIALLY MAINLY TO OUR EAST. HOWEVER...AS SURFACE HIGH PRESSURE SETTLES SOUTHWARD INTO THE CENTRAL/SOUTHERN PLAINS...LOW LEVEL MOISTURE INCREASES INTO OUR EASTERN PLAINS. THE GFS IN PARTICULAR HAS BEEN PRETTY ENERGETIC DEVELOPING WIDESPREAD AMOUNTS OF PRECIPITATION SUNDAY THROUGH MONDAY OVER THE EASTERN HALF OF NEW MEXICO...DESPITE THE REGION BEING UNDER A RATHER SHARP RIDGE ALOFT. BASED ON THE FORECAST POSITION OF THE RIDGE AXIS...THE ARGUMENT COULD BE MADE THAT THE EASTERN SIDE OF THE STATE WILL BE UNDER NORTHWEST FLOW ALOFT BUT IT WILL BE PRETTY WEAK. THE LATEST 00Z ECMWF IS EVEN JUMPING ON THIS IDEA THOUGH NOT QUITE AS EXTREME. CURRENT POP/WX GRIDS HAVE THIS TREND COVERED AT LEAST FOR NOW. THE MIDDLE TO LATE WEEK PERIOD NEXT WEEK APPEARS TO BECOME MORE UNSETTLED AS AN UPPER TROUGH PUSHES INTO THE GREAT BASIN AND HEADS FOR NEW MEXICO. THERE COULD BE POTENTIAL FOR A CLOSED LOW TO DEVELOP AS IT REACHES THE EASTERN SLOPES OF THE ROCKIES...BASED ON GFS/ECMWF. THERE/S STILL QUITE A BIT OF TIME FOR CHANGES...CONSIDERING THE NOW EXITING STORM SYSTEM WAS SUPPOSED TO BE DRY AND WINDY UNTIL ONLY A COUPLE OF DAYS PRIOR. && .AVIATION...AREAS OF LIGHT SNOW WILL AFFECT PORTIONS OF NORTHEAST NM THROUGH 16Z RESULTING IN MVFR/IFR CIGS/VSBYS AT TIMES... ESPECIALLY BETWEEN KLVS AND KRTN...AND NEAR THE NE NM/SE CO LINE. ELSEWHERE... LOW CLOUDS AND FOG OR FREEZING FOG WILL CONTINUE TO DEVELOP/EXPAND THROUGH DAYBREAK ESPECIALLY IN THE VALLEYS OF NC/NW NEW MEXICO THAT RECEIVED SIGNIFICANT PRECIP DURING THE PAST 24 HOURS. HIGHEST CONFIDENCE IN MVFR/BRIEF IFR CONDITIONS AT KSAF AND KABQ...AS WELL AS KSKX AND THE UPPER RIO GRANDE VALLEY. PRECIP ENDING AND CIGS RISING ACROSS NE NM BY MID- TO LATE MORNING AS THE STORM SYSTEM PULLS AWAY AND LOW LEVEL DOWNSLOPE FLOW AND VFR CONDITIONS RETURN. ELSEWHERE...ASIDE FROM MORNING LOW CLOUDS/FOG OR FREEZING FOG...VFR CONDITIONS EXPECTED. KJ NEXT AVIATION DISCUSSION SCHEDULED FOR 21Z. && .FIRE WEATHER...TEMPERATURES QUICKLY REBOUND TODAY...ALTHOUGH MAXES WILL REMAIN JUST SHY OF SEASONAL AVERAGES ACROSS MUCH OF THE CENTRAL AND EAST. THE NORTHEAST WILL BE SLOWEST TO RECOVER AND HIGHS THERE WILL BE 5 TO 10 DEGREES BELOW NORMAL. WITH THE WARMING....AFTERNOON HUMIDITY VALUES WILL TREND DOWNWARD IN A BIG WAY ESPECIALLY CENTRAL AND NORTH CENTRAL AREAS. RH VALUES LOOK TO BOTTOM OUT IN THE TEENS ACROSS THE SOUTH AND WEST...WITH MOSTLY 20S TO NEAR 40 ELSEWHERE. VENTILATION WILL BE VERY GOOD TO EXCELLENT FOR A VAST MAJORITY OF THE AREA LATER TODAY THANKS TO DEEP LAYER NORTHWEST FLOW ON THE BACKSIDE OF THE DEPARTING STORM SYSTEM. THIS WILL TRANSLATE TO MODERATE NORTHWEST BREEZES FOR MANY AREAS...ESPECIALLY EAST OF THE CENTRAL MOUNTAIN CHAIN AND PORTIONS OF WEST CENTRAL NEW MEXICO. A BRISK NORTH TO NORTHWEST WIND WILL ALSO DEVELOP ACROSS THE NORTHEAST ONCE AREAS OF LIGHT SNOW END AFTER MID OR LATE MORNING. WEAK HIGH PRESSURE ALOFT SLIDES OVER THE AREA TONIGHT. GIVEN THE EFFECTS OF MELTING SNOW ON BOUNDARY LAYER MOISTENING...LOW CLOUDS AND FOG/FREEZING FOG MAY REVISIT THE VALLEYS OF NORTHERN NEW MEXICO TOWARD DAYBREAK THURSDAY. OTHERWISE THE DRYING AND WARMING TREND WILL CONTINUE THROUGH THE END OF THE WORK WEEK. VENTILATION RATES WILL BE IN THE EXCELLENT CATEGORY BOTH DAYS FOR A VAST MAJORITY OF THE AREA. AFTERNOON AND EVENING WINDS WILL BE MORE NOTICEABLE THURSDAY AND ESPECIALLY FRIDAY AS MID-LEVEL GRADIENTS TIGHTEN AND BECOME MORE WEST TO SOUTHWEST BY FRIDAY. WESTERN AREAS AND THE NORTHEAST WILL BE FAVORED FOR BREEZY CONDITIONS THURSDAY AFTERNOON WITH MORE WIDESPREAD BREEZY/WINDY CONDITIONS ON FRIDAY. HOWEVER...RECENT MODEL TRENDS NOW SUPPORT LESS OVERALL WIND IMPACTS ON FRIDAY AS THE MAIN SHORTWAVE IS LIFTING OUT FARTHER NORTH. EVEN SO...DEEP MIXING DURING THE AFTERNOON/EVENING WILL BRING THE HIGHER MOMENTUM AIR TO THE SURFACE AND COMBINED WITH LOWERING RH/S WILL RESULT IN AN INCREASING THREAT FOR LOW END CRITICAL FIRE WEATHER GROWTH CONDITIONS MAINLY ACROSS THE EAST CENTRAL PLAINS. WEAK RIDGE ALOFT INDICATED SATURDAY AND SUNDAY WITH LESS WIND AREAWIDE...THOUGH STRENGTHENING SOUTH OR SOUTHEAST SURFACE GRADIENTS LIKELY ACROSS THE FAR EAST. WE WILL BE MONITORING LOW LEVEL MOISTURE RETURN ACROSS PORTIONS OF SOUTH CENTRAL AND SOUTHEAST NEW MEXICO LATE IN THE WEEKEND INTO EARLY NEXT WEEK...AS THE LARGE SCALE WIND PATTERN IS FAVORABLE TO ALLOW FOR A SUBTLE BUT POTENTIALLY SIGNIFICANT INCREASE BEGINNING SUNDAY. THIS COULD RESULT IN A THREAT OF HIGH BASED SHOWERS OR VIRGA AT A MINIMUM...AND POSSIBLY DRYLINE-ENHANCED THUNDERSTORMS ACROSS THE FAR EAST. HOW FAR WEST AND NORTH THIS VIRGA THREAT EXPANDS IS VERY UNCERTAIN...BUT AREAS ALONG AND EAST OF THE CENTRAL MOUNTAIN CHAIN WILL BE VERY SUSCEPTIBLE AND CLIMATOLOGICALLY-FAVORED. KJ && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 66 35 73 37 / 0 0 0 0 DULCE........................... 58 25 66 30 / 10 0 0 0 CUBA............................ 57 30 66 33 / 5 0 0 0 GALLUP.......................... 66 30 68 32 / 0 0 0 0 EL MORRO........................ 59 27 66 30 / 0 0 0 0 GRANTS.......................... 63 29 68 31 / 0 0 0 0 QUEMADO......................... 63 33 69 33 / 0 0 0 0 GLENWOOD........................ 71 35 75 41 / 0 0 0 0 CHAMA........................... 51 28 59 28 / 20 0 0 0 LOS ALAMOS...................... 57 37 67 38 / 10 0 0 0 PECOS........................... 54 35 65 38 / 5 0 0 0 CERRO/QUESTA.................... 53 27 64 31 / 10 5 0 0 RED RIVER....................... 45 28 54 30 / 20 5 0 0 ANGEL FIRE...................... 46 26 56 30 / 30 5 0 0 TAOS............................ 55 27 65 31 / 10 0 0 0 MORA............................ 50 30 62 33 / 20 5 0 0 ESPANOLA........................ 62 30 71 38 / 5 0 0 0 SANTA FE........................ 57 36 68 39 / 5 0 0 0 SANTA FE AIRPORT................ 60 35 70 38 / 5 0 0 0 ALBUQUERQUE FOOTHILLS........... 65 41 73 44 / 0 0 0 0 ALBUQUERQUE HEIGHTS............. 65 44 73 46 / 0 0 0 0 ALBUQUERQUE VALLEY.............. 67 38 75 45 / 0 0 0 0 ALBUQUERQUE WEST MESA........... 66 42 74 45 / 0 0 0 0 LOS LUNAS....................... 69 38 77 44 / 0 0 0 0 RIO RANCHO...................... 65 42 74 45 / 0 0 0 0 SOCORRO......................... 72 40 79 47 / 0 0 0 0 SANDIA PARK/CEDAR CREST......... 62 35 71 40 / 0 0 0 0 TIJERAS......................... 64 37 73 40 / 0 0 0 0 MORIARTY/ESTANCIA............... 59 33 70 38 / 0 0 0 0 CLINES CORNERS.................. 58 36 68 40 / 5 0 0 0 GRAN QUIVIRA.................... 62 38 72 43 / 0 0 0 0 CARRIZOZO....................... 65 37 74 43 / 0 0 0 0 RUIDOSO......................... 58 41 68 47 / 0 0 0 0 CAPULIN......................... 49 32 67 37 / 40 5 0 0 RATON........................... 56 31 69 35 / 30 5 0 0 SPRINGER........................ 59 32 72 38 / 20 5 0 0 LAS VEGAS....................... 58 33 68 39 / 10 5 0 0 CLAYTON......................... 58 37 75 43 / 20 5 0 0 ROY............................. 60 35 73 42 / 10 5 0 0 CONCHAS......................... 66 38 79 45 / 10 0 0 0 SANTA ROSA...................... 68 38 79 44 / 10 0 0 0 TUCUMCARI....................... 69 39 81 45 / 10 0 0 0 CLOVIS.......................... 69 40 80 46 / 10 0 0 0 PORTALES........................ 70 40 81 46 / 10 0 0 0 FORT SUMNER..................... 72 41 84 46 / 10 0 0 0 ROSWELL......................... 77 43 87 48 / 5 0 0 0 PICACHO......................... 71 41 82 48 / 0 0 0 0 ELK............................. 68 41 77 47 / 0 0 0 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
510 AM EDT WED APR 4 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN TODAY, BRINGING SUNNY SKIES LATER THIS MORNING AND BREEZY CONDITIONS. HIGH PRESSURE WILL KEEP QUIET WEATHER OVER THE AREA THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... IT IMAGERY AND GROUND OBS STILL SHOWING CLOUD COVER OVER MOST OF THE CWA, WITH SOME CLEARING FROM THE NW. THIS CLEARING WILL SLOWLY CONTINUE UNTIL AROUND DAY BREAK WHEN MIXING BEGINS TO CLEAR IT OUT SOMEWHAT FASTER. THIS WILL ALLOW FOR SUNNY SKIES LATER THIS MORNING AND THE REST OF THE DAY. AS HIGH PRESSURE BUILDS IN, THE PRESSURE GRADIENT WILL INCREASE OVER THE CWA, ALLOWING FOR WINDS TO INCREASE WITH GUSTS TO AROUND 20 MPH. RELATIVE HUMIDITY WILL BE FAIRLY DRY TODAY, DROPPING TO AROUND 30 PERCENT. MODELS HAVE MORE MOISTURE THAN THAT, BUT THINKING IS THEY ARE OVER DOING SFC MOISTURE, SO HAVE LOWERED DEW POINTS INTO THE UPPER 20S TO LOW 30S TODAY. THE HRRR SEEMS TO HAVE ONE OF THE BEST HANDLES ON THE RH TODAY. IT DOES SHOW INCREASING RH FROM THE NW THIS MORNING, ONLY TO FALL OFF LATE MORNING AND AFTERNOON AS MIXING OCCURS. EVEN WITH THE LOWERING RH, IT STILL SHOWS RH VALUES IN THE 40 PERCENT RANGE. SO, STARTING THERE AND TAKING ABOUT 10 PERCENT OFF OF THAT, STILL KEEPS FIRE WEATHER CONCERNS MARGINAL AT BEST. NOT TO MENTION, THE PRECIP CRITERIA HAS NOT BEEN MET FOR NY, AS MUCH OF THE CWA RECEIVED OVER A QUARTER INCH OF RAIN ON SUNDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH THE REMAINDER OF THE WEEK. THIS WILL KEEP THE WEATHER QUIET. LOOKING AT TEMPS TONIGHT, THEY WILL COOL TO THE LOWER 30S. THERE MAY BE SOME LOCALIZED AREAS OF BELOW FREEZING TEMPS, BUT NOT EXPECTED TO BE WIDESPREAD AT THIS TIME IN AREAS WHERE THE GROWING SEASON HAS STARTED. THUS, HAVE OPTED NOT TO ISSUE ANY PRODUCTS AT THIS TIME. && .LONG TERM /SATURDAY THROUGH TUESDAY/... .0345 AM UPDATE... VERY FEW CHANGES MADE TO THE LONG TERM AS PREVIOUS FORECAST HAD A GOOD HANDLE ON EXPECTED CONDITIONS. IN GENERAL...DRY/SEASONAL CONDITIONS EXPECTED TOWARDS THE START OF THE PERIOD WITH AN EVENTUAL SHIFT TOWARDS UNSETTLED CONDITIONS AND BELOW NORMAL TEMPS EARLY NEXT WEEK AS AN UPPER VORTEX BECOMES FIRMLY ESTABLISHED ACROSS EASTERN CANADA. BOTH GFS AND ECMWF SHOWING SURPRISING AGREEMENT WITH THE EVOLUTION OF THIS FEATURE...WITH BOTH AGREEING UPPER LOW WILL TAKE UP RESIDENCE ACROSS THE UPPER ST. LAWRENCE VALLEY BY MONDAY. UNFORTUNATELY...OUR REGION WILL BE EMBEDDED IN NORTHERLY FLOW TO THE SYSTEM/S WEST WHICH WILL SET UP A FAVORABLE CORRIDOR FOR THE PASSAGE OF UPPER SHORTWAVE DISTURBANCES ACROSS OUR REGION. BASED ON FAVORABLE MODEL AGREEMENT...HAVE LOWERED DAYTIME HIGHS A FEW DEGREES EACH DAY BEGINNING MON. .PREVIOUS LONG TERM DISCUSSION... THE LONG TERM STARTS OFF WITH HIGH PRESSURE IN CONTROL WITH FAIR AND MAINLY CLEAR WX FOR FRI AND SAT AND MOST OF SUNDAY. LATER ON SUNDAY...A WEAK FNTL SYSTEM MAY BRING AN INCREASE IN CLDS AND THE CHC FOR A FEW -SHRA ON SUN NGT. AFTER THIS TIME MDLS ARE IN PRETTY GOOD AGREEMENT THAT AN UPR TROF WILL BE AMPLIFYING OVER THE RGN WITH A TREND TWDS COOLER AND WETTER CONDITIONS TAKING HOLD. WE FOLLOWED HPC GDNC FOR THE MOST PART...BUT LOWERED MAXES A BIT FOR EARLY NXT WEEK GIVEN MDL TRENDS AND LATEST MOS GDNC. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD DESPITE PASSAGE OF WEAK SURFACE FRONT THIS MORNING. LATEST 11-3.9U SATELLITE TRENDS SHOWING MID-LEVEL DECK EXITING OFF TOWARDS THE SOUTHEAST THIS MORNING...WHICH WILL BE FOLLOWED BY A PERIOD OF MOSTLY CLEAR SKIES AFTER 09-10Z TIME FRAME. CLOUDS WILL AGAIN BE ON THE INCREASE THIS AFTERNOON AS UPPER-LEVEL DISTURBANCE BRUSHES THE REGION FROM THE NORTH. BRISK NW WINDS ARE ALSO EXPECTED TODAY AS A TIGHT PRESSURE GRADIENT WILL REMAIN OVER THE REGION. BY LATE MORNING/AFTERNOON...GUSTS MAY REACH AS HIGH AS 25 KTS AT ALL TAF SITES BEFORE WINDS BEGIN TO WEAKEN THIS EVENING. .OUTLOOK... WED NGT TO SUN...VFR. POTNL FOR A PD OF MVFR CIGS ACRS CNTRL NY S/SE OF LAKE ONTARIO LATE WED NGT INTO EARLY THU MRNG. && .FIRE WEATHER... WHILE THERE IS A HIGH FIRE DANGER IN SOME AREAS, RED FLAG CRITERIA LOOKS TO NOT BE MET, OR FAIRLY MARGINAL IN SOME AREAS. FOR THE NEW YORK AREA, RAIN ON SUNDAY OF MORE THAN A QUARTER OF AN INCH OVER A LARGE AREA, HAS KEPT THE CRITERIA FROM BEING MET. ALSO, RELATIVE HUMIDITY WILL DROP TODAY. HOWEVER, IT DOES LOOK TO REMAIN IN THE LOW 30 PERCENT RANGE IN THE CATSKILL AREA. ALSO, WINDS ARE EXPECTED TO BE GUSTY TODAY, WITH SOME GUSTS APPROACHING 25 MPH, AGAIN, ESPECIALLY IN THE CATSKILL REGION. THIS, WHEN COMBINED WITH LOW FUEL MOISTURE, WOULD CAUSE BORDERLINE CONDITIONS, BUT NOT EXPECTING EXPLOSIVE FIRE GROWTH POTENTIAL AT THIS TIME. TEMPS WILL BE NEAR FREEZING OVER MUCH OF THE AREA TONIGHT. RH RECOVERY WILL BE MODERATE, WITH VALUES IN THE UPPER 60 TO MID 70 PERCENT RANGE. FOR TOMORROW, RH WILL NOT BE AS LOW AND WINDS WILL ARE NOT EXPECTED TO BE AS STRONG, THUS REDUCING THE THREAT OF REACHING CRITICAL FIRE WEATHER CONDITIONS. THIS WILL BE THE GENERAL RULE FOR THE REMAINDER OF THE WEEK AS HIGH PRESSURE BUILDS IN AND REMAINS IN CONTROL THROUGH THE WEEKEND. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI NEAR TERM...SLI SHORT TERM...SLI LONG TERM...CMG AVIATION...CMG FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
320 AM EDT WED APR 4 2012 .SYNOPSIS... A STRONG BACK DOOR COLD FRONT WILL APPROACH FROM THE NORTH THIS EVENING AND SURGE SOUTHWARD THROUGH THE AREA LATE TONIGHT AND THURSDAY MORNING. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 315 AM WEDNESDAY... OVERVIEW: THE HEIGHT GRADIENT ALOFT WILL TIGHTEN OVER THE CAROLINAS AND MID-ATLANTIC TODAY IN ASSOC/W MODEST HEIGHT FALLS IN ADVANCE OF AN H5 TROUGH PROGRESSING SLOWLY S/SE FROM CANADA INTO THE LOWER GREAT LAKES AND NEW ENGLAND. ALTHOUGH DPVA WITH THE AFOREMENTIONED TROUGH WILL REMAIN WELL NORTH IN NEW ENGLAND...STRENGTHENING WESTERLY FLOW ALOFT WILL RESULT IN A POTENTIAL FOR DPVA IN THE FORM OF MINOR SHORTWAVES/MCVS ADVECTING INTO NC/VA FROM THE WEST THIS AFTERNOON INTO TONIGHT. IN ADDITION TO AN MCV NOTED OVER CENTRAL NC (VIA LATEST RUC DATA) AT 06Z...SEVERAL MCVS/DISTURBANCES WERE NOTED UPSTREAM OVER THE CENTRAL/LOWER MS RIVER VALLEY THIS MORNING. IN THE LOWER LEVELS...THE WARM FRONT PROGRESSING NORTH THROUGH SOUTHERN VA AS OF 06Z WILL STALL OUT IN NORTHERN VA TODAY...THEN RETREAT SOUTHWARD AS A BACK DOOR COLD FRONT THIS AFTERNOON AND EVENING...WITH A PRE-FRONTAL TROUGH PROGRESSING INTO CENTRAL NC BY 18-21Z. THE COLD FRONT WILL PROGRESS SOUTH THROUGH CENTRAL NC LATE TONIGHT/THU MORNING. PRECIPITATION CHANCES: THOUGH STEEP MID-LEVEL LAPSE RATES (7-8 C/KM) WERE PRESENT OVER NC/VA AND THE OH VALLEY AT 06Z THIS MORNING...MODEL GUIDANCE CONTINUES TO INDICATE LAPSE RATES WEAKENING TO 5.5-6 C/KM BETWEEN 18-00Z. HOWEVER...AN UNSEASONABLY WARM/MOIST AIRMASS WILL BE IN PLACE ACROSS CENTRAL NC TODAY...AND THIS SHOULD ALLOW FOR 500-1000 J/KG OF MLCAPE DURING PEAK HEATING...PERHAPS 1000-1500 J/KG IF MID-LEVEL LAPSE RATES REMAIN NEAR OR SLIGHTLY ABOVE 6 C/KM... PRIMARILY BETWEEN 18-21Z. GIVEN A LOW-LEVEL FOCUS (PRE-FRONTAL TROUGH) AND A POTENTIAL FOR DISTURBANCES ALOFT ADVECTING INTO THE AREA FROM THE WEST IN THE PRESENCE OF MARGINAL TO MODERATE INSTABILITY...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP BETWEEN 18-21Z THIS AFTERNOON. HOWEVER...UNCERTAINTY IN THE TIMING AND LOCATION OF CONVECTION PERSISTS...PRIMARILY IN ASSOCIATION WITH THE TRACK/EVOLUTION OF UPSTREAM DISTURBANCES ADVECTING TOWARD NC/VA VIA STRENGTHENING WESTERLY FLOW ALOFT. THE LATEST 00Z WRF-NMM INDICATES DRY CONDITIONS THROUGH 18Z...SHOWING ISOLD/SCT CONVECTION DEVELOPING OVER THE MOUNTAINS AND MOVING DOWNSTREAM INTO THE CENTRAL NC BY 21Z THIS AFTERNOON...WITH ADDITIONAL CONVECTION DEVELOPING IN VICINITY OF THE PRE-FRONTAL TROUGH OVER CENTRAL NC. THE 00Z WRF-ARW SHOWS SCATTERED CONVECTION DEVELOPING OVER CENTRAL NC PRIMARILY IN ASSOC/W THE PRE-FRONTAL TROUGH BETWEEN 18-21Z. AT THIS TIME WILL NOT CHANGE PRECIP CHANCES MUCH FROM THE PREVIOUS FORECAST...SHOWING A 40% CHANCE FOR SHOWERS/STORMS...WITH THE BEST CHANCE BETWEEN 19Z THIS AFTERNOON AND 01Z THIS EVENING. THOUGH INSTABILITY WILL BEGIN TO WANE AFTER SUNSET...ADDITIONAL CONVECTION WILL BE POSSIBLE IN ASSOC/W THE BACK DOOR COLD FRONT PROGRESSING SOUTH THROUGH VA INTO CENTRAL NC OVERNIGHT. HOWEVER...THIS MAY DEPEND ON HOW MUCH STABILIZATION OCCURS IN ASSOC/W CONVECTION DURING THE AFTERNOON AND EVENING. WILL MAINTAIN A SLIGHT CHANCE (20%) NORTH TO LOW CHANCE (30%) SOUTH OVERNIGHT...WITH ISOLD THUNDERSTORMS MORE LIKELY IN SOUTHERN PORTIONS OF THE AREA. TEMPERATURES: 1000-850 MB THICKNESSES ARE PROGGED AT 1390-1400 METERS THIS AFTERNOON. THESE THICKNESSES SUPPORT HIGHS IN THE LOWER/MID 80S... OR 82-85F. ALTHOUGH A FAIR AMOUNT OF MID/UPPER LEVEL CLOUD COVER IS PRESENT THIS MORNING...EXPECT A REASONABLE POTENTIAL FOR SOME CLEARING AND ENOUGH SUNSHINE FOR TEMPS TO REACH THE LOWER/MID 80S. LOWS TONIGHT WILL DEPEND ENTIRELY ON THE TIMING/PROGRESS OF THE BACK DOOR COLD FRONT SURGING SOUTH INTO THE AREA. AT THIS TIME...EXPECT LOWS TO RANGE FROM THE LOWER/MID 50S IN THE NORTH/NE TO THE UPPER 50S AND LOWER 60S IN THE SOUTH. SEVERE THREAT: THE SPC DAY 1 OUTLOOK INDICATES A SLIGHT RISK OF SEVERE STORMS TODAY OVER MOST OF CENTRAL NC. AS WESTERLY FLOW ALOFT STRENGTHENS...0-6 KM BULK SHEAR VALUES IN CENTRAL NC ARE EXPECTED TO INCREASE TO 25-35 KT THIS AFT/EVE...FURTHER INCREASING TO 30-40 KT AFTER 00Z. 0-6KM BULK SHEAR VALUES WILL CERTAINLY BE SUPPORTIVE OF MULTICELL ORGANIZATION...AND MAY BE AT THE LOW-END THRESHOLD FOR SUPERCELLULAR ORGANIZATION...PRIMARILY AFTER 00Z...OR IF THE HEIGHT GRADIENT ALOFT TIGHTENS/MID-LEVEL FLOW ACCELERATES IN ADVANCE OF AN UPPER LEVEL DISTURBANCE PROGRESSING INTO THE AREA THIS AFT/EVE (SHOULD THAT OCCUR). STEEP LOW-LEVEL LAPSE RATES ASSOC/W STRONG DIURNAL HEATING WILL CONTRIBUTE TO RELATIVELY HIGH DCAPE AND THE POTENTIAL FOR STRONG COLD POOLS THIS AFT/EVE. WITH THE ABOVE IN MIND...EXPECT THE BEST CHANCE FOR SEVERE WEATHER FROM 3-10 PM...WITH A PRIMARY THREAT OF DAMAGING WINDS OWING TO STEEP LOW-LEVEL LAPSE RATES AND RELATIVELY SPEEDY MID-LEVEL FLOW. SEVERE HAIL APPEARS LESS LIKELY GIVEN WEAK MID-LEVEL LAPSE RATES AND BULK SHEAR VALUES ON THE LOW-END OF/OR UNSUPPORTIVE OF ROTATING UPDRAFTS. GIVEN STRONG HEATING AND STEEP LOW-LEVEL LAPSE RATES...IF CONVECTION INITIATES ON THE HIGHER TERRAIN AND PROGRESSES EAST INTO CENTRAL NC DURING THE MID/LATE AFTERNOON...A LINE OF STORMS (ORGANIZING ALONG OUTFLOW) COULD DEVELOP AND POSE A THREAT FOR RELATIVELY WIDESPREAD DAMAGING WINDS. -VINCENT && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 310 AM WEDNESDAY... AN UPPER LOW CURRENTLY LIFTING OUT OF NORTHEAST NM WILL DRIFT EAST ACROSS THE MID MS RIVER VALLEY WEDNESDAY NIGHT... AND THEN BEGIN TO MOVE SOUTHEAST TOWARD AL/GA ON THURSDAY AS IT APPROACHES THE SOUTHERN EDGE OF BROAD CYCLONIC FLOW OVER THE NORTHEAST US. A COLD FRONT AND/OR REMNANT CONVECTIVE OUTFLOW SHOULD BE NEAR THE NC/SC BORDER BY 12Z THURSDAY...WHERE A FEW ISOLATED SHOWERS CANNOT BE RULED OUT DURING THE MORNING HOURS. HOWEVER...MOST OF THE CENTRAL NC SHOULD BE DRY THROUGH THURSDAY AFTERNOON AS A SURFACE HIGH PRESSURE RIDGE SETTLES IN BEHIND THE FRONT AND A WEAK SHORTWAVE UPPER RIDGE SHIFTS ACROSS NC AHEAD OF THE APPROACHING UPPER LOW. WHILE FORECAST SOUNDINGS SUGGEST THE BOUNDARY LAYER WILL BE SLOW TO SATURATE UNTIL LATER THURSDAY EVENING...THE LOW LEVEL COLD ADVECTION BEHIND THE FRONT SHOULD BE HELP TO LOCK IN STRATUS AT 2-3K FT WHERE MOISTURE WILL ALREADY EXIST. THUS...TEMPS WILL STRUGGLE TO RISE UNTO THE LOW TO MID 60S...A GOOD 20 DEGREES COOLER THAN WEDNESDAY. FORCING FOR ASCENT...IN THE FORM OF INCREASING DIVERGENCE ALOFT...WEAK LOW LEVEL WARM ADVECTION AND 60-80M HEIGHT FALLS...WILL ARRIVE THURSDAY EVENING AS THE UPPER LOW DIVES THROUGH AL/GA. WHILE THERE HAS BEEN GOOD MODEL CONSISTENCY IS THE GENERAL TRACK OF THE UPPER AND SURFACE LOWS...THERE ARE STILL 100-200 MILE DIFFERENCES THAT WILL IMPACT HOW FAR NORTH INTO NC BETTER RAIN COVERAGE WILL EXTEND. MOST OF THE SHOWERS WILL PASS TO OUR SOUTH THURSDAY NIGHT AS THE SURFACE LOW DEVELOPS AND MOVES TO NEAR SAVANNAH BY 06-12Z FRIDAY. HOWEVER...A SHORTWAVE DROPPING SOUTH OUT OF EASTERN CANADA INTO THE MID-ATLANTIC STATES SHOULD HELP DRAW MOISTURE NORTH INTO THE VICINITY OF THE 925-850MB FRONT WHICH IS FORECAST TO LIE ACROSS THE CAROLINAS. MODELS HAVE BEEN SHOWING AN AREA OF INCREASE LOW LEVEL FGEN DEVELOPING OVER NC LATER FRIDAY NIGHT...SO WHILE THE BEST SURFACE CONVERGENCE AND UPPER FORCING WILL BE JUST TO OUR SOUTH...WE SHOULD SEE PRECIP EXPAND AND INTENSIFY NORTHWARD ACROSS SOUTHERN AND EASTERN NC OVERNIGHT. WE DO NOT EXPECT ANY CONVECTION THURSDAY NIGHT AS LOW LEVELS WILL BE STABLE...MID LEVEL LAPSE RATES WILL BE WEAK... AND THE STRONGEST UPPER FORCING WILL BE TO OUR SOUTH. HOWEVER...IF THE SURFACE LOW TRACKS SLIGHTLY NORTH OF THE CURRENT FORECAST...THERE COULD BE ENOUGH INSTABILITY ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS TO SUPPORT A FEW ISOLATED THUNDERSTORMS. FORECAST POPS ARE ALREADY HIGH ACROSS THE SOUTH AFTER 21Z THURSDAY...EXPANDING NORTHWARD AFTER 03Z...WHICH SEEMS SUFFICIENT FOR THE CURRENT FORECAST PACKAGE. LOWS IN THE UPPER 40S. THE SURFACE LOW SHOULD BE OFF THE SC COAST BY 12Z FRIDAY..WITH PRECIP ENDING FROM WEST TO EAST DURING THE DAY. THE MSLP GRADIENT ON THE BACK SIDE OF THE SURFACE LOW WILL BE FAIRLY TIGHT...WITH MOST MODELS SHOWING A 15-20KT NORTHEASTERLY WIND OVER THE COASTAL PLAIN FRIDAY MORNING. THE DEPARTING LOW WILL ALSO DRAW DRIER AIR IN FROM THE NORTH AS WINDS BEGIN TO TURN TO NORTH-NORTHWESTERLY FRIDAY AFTERNOON. FORECAST SOUNDINGS NOW SHOW MOST OF THE CENTRAL BREAKING OUT FRIDAY...ALTHOUGH MODELS OFTEN HAVE A TENDENCY TO SCOUR LOW LEVEL MOISTURE TOO QUICKLY IN THE ABSENCE OF A FRONTAL SYSTEM. BECAUSE OF THIS...THE HIGH TEMP FORECAST FOR FRIDAY IS SOMEWHAT UNCERTAIN...BUT IT IS POSSIBLE THAT AREA SIN THE WEST COULD BREAK OUT AND BE AS WARM IF NOT WARMER THAN AREAS IN THE EAST. WILL FORECAST HIGHS GENERALLY AROUND 60. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 350 AM WEDNESDAY... HIGH PRESSURE OVER THE GREAT LAKES WILL BRIEFLY BUILD SOUTH ACROSS MUCH OF THE EASTERN US THIS WEEKEND...WHILE SEVERAL SHORTWAVES OVER EASTERN CANADA AND THE NORTHERN US WRAP UP OVER NEW ENGLAND AND LEAD TO A DEEP TROUGH ALONG THE EAST COAST NEXT WEEK. RAIN CHANCES APPEAR TO BE LOW BUT ALSO LESS PREDICTABLE DUE TO THE NORTHWESTERLY FLOW REGIME...ESPECIALLY FROM SUNDAY NIGHT ONWARD. HIGHS WARMING INTO THE LOW TO MID 70S BY SUNDAY WILL DROP BACK INTO THE 60S FOR THE FIRST HALF OF NEXT WEEK. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 135 AM WEDNESDAY... 24-HR TAF PERIOD: WEAKENING SHOWERS AND STORMS OVER RICHMOND/SCOTLAND COUNTIES AT 05Z MAY AFFECT THE FAY TERMINAL BETWEEN 06-09Z THIS MORNING. ASIDE FROM THAT AND A SMALL POTENTIAL (SREF PROBS <20%) FOR SUB-VFR CEILINGS OR VISBYS IN THE 09-12Z TIME FRAME...EXPECT VFR CONDITIONS TO PREDOMINATE THROUGH 18Z THIS AFTERNOON. BY MID TO LATE AFTERNOON... EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO BE POSSIBLE AT ALL TAF SITES IN ADVANCE OF A STRONG BACK DOOR COLD FRONT APPROACHING FROM THE NORTH...WITH SHOWERS/STORMS PERSISTING IN SOME AREAS THROUGH THE END OF THE TAF PERIOD. WINDS WILL BE WEST OR SW AT 5-10 KT THROUGH 00Z THIS EVENING...BECOMING NORTH AND EVENTUALLY NORTHEAST BY THE END OF THE TAF PERIOD. LOOKING AHEAD: BREEZY NORTHEAST WINDS (10-15 KT GUSTING TO 20 KT) CAN BE EXPECTED IN THE WAKE OF THE BACK DOOR COLD FRONTAL PASSAGE BETWEEN 09-18Z THURSDAY...ALONG WITH OVERCAST CEILINGS BETWEEN 3000-4500 FT AGL. AFTER 18Z THU INTO THU NIGHT...MVFR CONDITIONS AND LIGHT RAIN ARE EXPECTED IN ASSOC/W A DEVELOPING LOW PRESSURE SYSTEM OFF THE SOUTHEAST COAST. IFR CONDITIONS WILL BE POSSIBLE. MVFR/IFR CEILINGS ARE EXPECTED TO LIFT AND SCATTER OUT BETWEEN 12-18Z FRIDAY IN ASSOC/W DRY AIR ADVECTING INTO THE AREA VIA BREEZY NNE FLOW. VFR CONDITIONS ARE EXPECTED TO PERSIST FROM EARLY FRIDAY AFTERNOON INTO THE WEEKEND. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...SMITH LONG TERM...SMITH AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
312 AM EDT WED APR 4 2012 .SYNOPSIS... A SERIES OF WEAK DISTURBANCES ALOFT...FRONTS AND A MORE POTENT STORM SYSTEM WILL KEEP CONDITIONS UNSETTLED THROUGH FRIDAY. SPRING LIKE CONDITIONS QUICKLY RETURN FOR THE WEEKEND AND CONTINUE INTO EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM...HRRR MODEL OUTPUT INDICATES THE CLUSTER OF CONVECTION ACROSS THE CENTRAL PORTIONS OF THE CAROLINAS IS PROGGED TO MAKE SLOW EASTWARD PROGRESS...POSSIBLY REACHING THE WESTERN EDGE OF THE ILM CWA AT OR UP TO A FEW HRS AFTER MIDNIGHT. BY THAT TIME...INSTABILITY WILL BE LACKING ESPECIALLY HAVING TRACKED INTO AN ATM ALREADY NONCONDUCIVE FOR TSRA ACTIVITY TO START WITH. WEAK MID LEVEL VORTICIES OVER THE WEST/CENTRAL CAROLINAS ARE AIDING THE FORCING NEEDED TO SUSTAIN THIS CONVECTION AS IT APPROACHES THE ILM CWA FROM THE WEST DURING THE OVERNIGHT. AS INDICATED B4...HRRR SFC BASED CAPE BASICALLY NON-EXISTENT ACROSS THE ILM CWA BY THE TIME THIS ACTIVITY REACHES THE OUTSKIRTS OF THE ILM CWA. WITH THIS SAID...WILL CONTINUE CURRENT TREND WITH ONLY LOW CHANCE POPS OVERNIGHT...MAINLY ALONG THE WEST THROUGH NORTHWEST OUTLINE OF THE ILM CWA. DUE TO LATEST SAT IMAGERY TRENDS AND SFC OBS...CURRENT FORECAST OF SKY CONDITIONS LOOKS AOK WITH NO CHANGES NEEDED. FOR MIN TEMP FORECAST AND OVERNIGHT DEWPOINTS...SOME TWEAKING UPWARDS NEEDED BY 1 TO AS MUCH AS 3 DEGREES BASED ON LATEST SFC OBS AND LAPS/MSAS ANALYSIS TRENDS...AND WITH SOME AID FROM THE LATEST RUNS OF THE HRRR AND RUC. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... AS OF 3:00 AM WEDNESDAY...MID LEVEL CYCLONE WILL MOVE QUICKLY ACROSS THE SOUTHEAST THROUGH THE PERIOD. THE SURFACE LOW WILL MOVE ALONG THE BAROCLINIC ZONE JUST SOUTH OF THE NC/SC BORDER. HPC FAVORS THE GFS SOLUTION AS THE NAM IS HAVING INITIALIZATION ISSUES. FOR OUR AREA...ISENTROPIC LIFT IN THE 290-300K LAYER INCREASES STEADILY FROM 0000 THROUGH 1200 FRIDAY WITH THE BEST OMEGA ALONG THE SOUTH CAROLINA AREAS. INCREASED POPS ACROSS THE BOARD WITH THIS PACKAGE TO LOW END CATEGORICAL SOUTH TO NORTH. THE NORTH CAROLINA COAST MAY FARE BETTER DURING THE DAY FRIDAY AS MID LEVEL FRONTOGENESIS MOVES ACROSS THE AREA. BASED ON LIMITED INSTABILITY...HAVE ALL BUT REMOVED THUNDER FROM THE FORECAST...KEEPING ISOLATED EARLY THURSDAY. STORM TOTAL QPF AMOUNTS RANGE FROM APPROXIMATELY ONE THIRD OF AN INCH NORTH TO JUST UNDER EXTREME SOUTHERN AREAS. FOLLOWED GFS/MAV NUMBERS FOR THE TEMPERATURE FORECAST BUT OVERALL MAV AND MET NUMBERS ARE CLOSE. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 3:00 AM WEDNESDAY...RATHER UNEVENTFUL CONDITIONS SATURDAY AND SUNDAY AS HIGH PRESSURE SETTLES OVER THE AREA UNDER THE DEAMPLIYFING UPPER LEVEL PATTERN. AIR MASS MODIFICATION WILL ALLOW MAX TEMPERATURES TO REBOUND QUICKLY TO THE MIDDLE TO UPPER 70S SUNDAY AND MORESO ON MONDAY. MEDIUM RANGE MODELS (THE LATEST OPERATIONAL GFS AND CANADIAN) WANT TO DEVELOP A DEEPER EAST COAST TROUGH TUESDAY. THE ECMWF IS NOT QUITE ON BOARD ALTHOUGH THE ENSEMBLE MEAN DOES HAVE MORE AMPLITUDE WHEN COMPARED TO THE DETERMINISTIC MODEL. CERTAINLY NO COMPELLING REASON TO DEVIATE FROM THE FORECAST AT THIS POINT BUT A DEEPER TROUGH COULD BRING 850MB TEMPERATURES TANTALIZINGLY CLOSE TO FREEZING. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...SHOWERS AND THUNDERSTORMS WILL BE WEAKENING ACROSS THE INLAND TERMINALS THROUGH 08Z AS THEY CONTINUE E...PERHAPS AS FAR E AS CRE AND MYR AFTER 08Z. MODERATE CONFIDENCE IN IFR STRATUS ALONG THE COAST AFTER 08Z...OTHERWISE MVFR CEILINGS AND OR VISIBILITIES WILL BE LARGELY THE RULE THROUGH SUNRISE. INCREASING PRECIPITABLE WATER VALUES AND CAPES COUPLED WITH HEATING WILL PROVIDE AN ENVIRONMENT CONDUCIVE FOR AT LEAST SCATTERED CONVECTION THIS AFTERNOON. LOOK FOR THE RESULTANT BOUNDARY TO KICK OFF A FEW...WITH MORE SCATTERED CONVECTION INLAND. WINDS WILL BE SOUTHWESTERLY ALL DAY...GUSTY BY MID TO LATE MORNING. EXTENDED OUTLOOK...A GOOD CHANCE OF SHOWERS/EMBEDDED THUNDERSTORMS WITH WIDESPREAD IFR FRIDAY. VFR SATURDAY AND SUNDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM TUESDAY...CONTINUED MINOR ADJUSTMENTS TO WINDS OVERNIGHT...MAINLY CONTINUED DUE TO THE SLOW VEERING OF WIND DIRECTIONS FROM THE S TO SW AS A DIFFUSE WARM FRONT LIFTS ACROSS... AND NORTH OF THE ILM WATERS DURING THE OVERNIGHT. SPEEDS IN GENERAL TO REMAIN 10 TO OCCASIONALLY 15 KT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT THROUGHOUT. A 1 TO 2 FT EASTERLY GROUND SWELL AT 9-11 SECOND PERIODS WILL DOMINATE SIGNIFICANT SEAS...WITH A 1-2 FOOT 3 TO 5 SECOND PERIOD WIND DRIVEN CHOP ADDING A FOOT OR 2 TO THE OVERALL SIG. SEAS. COULD POSSIBLY SEE A FEW 4 FOOTERS ACROSS THE SHALLOW SHOALS OFF CAPE FEAR BUT CONTINUED NOT ENOUGH OF AN OCCURRENCE TO PLACE IN THE CWF. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 3:00 AM WEDNESDAY...WIND SHIFT WILL BE UNDERWAY AT THE BEGINNING OF THE PERIOD AS A FRONT BISECTS THE WATERS. BY LATE AFTERNOON ALL WATERS SHOULD SEE NORTHEASTERLY WINDS. LOW PRESSURE RIDES TO THE SOUTH VEERING WINDS TO ALMOST DUE EAST BY 0600 UTC FRIDAY BEFORE PULLING AWAY FRIDAY WITH WINDS SHIFTING BACK TO NORTHEAST. FOLLOWED THE GFS WHICH HAS VERY STRONG WINDS FROM FRIDAY AFTERNOON AND EVENING. COULD SEE SEVERAL GUSTS INTO THE GALE CRITERIA AND THIS WILL NEED TO BE MONITORED. SEAS ARE MAINLY A CONCERN FRIDAY AS THE WINDS PICK UP STEAM. HIGH CONFIDENCE ON SMALL CRAFT SEAS DEVELOPING BY 1200 UTC WITH THE EXCEPTION OF AMZ256. ALL WATERS SHOULD SEE WELL OVER SIX FEET BY MIDDAY. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 3:00 AM WEDNESDAY...HIGH PRESSURE WILL BUILD IN ACROSS THE WATERS THROUGH THE PERIOD. NORTHEAST WINDS ON THE ORDER OF 20-25 KNOTS INITIALLY WILL QUICKLY SUBSIDE TO 10-15 BY SUNDAY AM AS THE AXIS OF HIGH PRESSURE REPOSITIONS ALONG THE APPALACHIANS. RESIDUAL HIGH SEAS OF 6-8 FEET WILL FOLLOW CLOSE BEHIND DROPPING TO 2-4 FEET BY THE END OF THE PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SHK NEAR TERM...RJD SHORT TERM...SHK LONG TERM...SHK AVIATION...HDL/RJD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
140 AM EDT WED APR 4 2012 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTH THROUGH THE CAROLINAS WEDNESDAY NIGHT AND EARLY THURSDAY FOLLOWED BY A REINFORCING SHOT OF COLD AIR FRIDAY NIGHT INTO SATURDAY AS STRONG HIGH PRESSURE BUILDS DOWN ACROSS THE CAROLINAS. HIGH PRESSURE WILL WEAKEN AS IT MOVES OFFSHORE ON MONDAY AS YET ANOTHER COLD FRONT APPROACHES FROM THE NORTHWEST. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM...HRRR MODEL OUTPUT INDICATES THE CLUSTER OF CONVECTION ACROSS THE CENTRAL PORTIONS OF THE CAROLINAS IS PROGGED TO MAKE SLOW EASTWARD PROGRESS...POSSIBLY REACHING THE WESTERN EDGE OF THE ILM CWA AT OR UP TO A FEW HRS AFTER MIDNIGHT. BY THAT TIME...INSTABILITY WILL BE LACKING ESPECIALLY HAVING TRACKED INTO AN ATM ALREADY NONCONDUCIVE FOR TSRA ACTIVITY TO START WITH. WEAK MID LEVEL VORTICIES OVER THE WEST/CENTRAL CAROLINAS ARE AIDING THE FORCING NEEDED TO SUSTAIN THIS CONVECTION AS IT APPROACHES THE ILM CWA FROM THE WEST DURING THE OVERNIGHT. AS INDICATED B4...HRRR SFC BASED CAPE BASICALLY NON-EXISTENT ACROSS THE ILM CWA BY THE TIME THIS ACTIVITY REACHES THE OUTSKIRTS OF THE ILM CWA. WITH THIS SAID...WILL CONTINUE CURRENT TREND WITH ONLY LOW CHANCE POPS OVERNIGHT...MAINLY ALONG THE WEST THROUGH NORTHWEST OUTLINE OF THE ILM CWA. DUE TO LATEST SAT IMAGERY TRENDS AND SFC OBS...CURRENT FORECAST OF SKY CONDITIONS LOOKS AOK WITH NO CHANGES NEEDED. FOR MIN TEMP FORECAST AND OVERNIGHT DEWPOINTS...SOME TWEAKING UPWARDS NEEDED BY 1 TO AS MUCH AS 3 DEGREES BASED ON LATEST SFC OBS AND LAPS/MSAS ANALYSIS TRENDS...AND WITH SOME AID FROM THE LATEST RUNS OF THE HRRR AND RUC. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...VERY LOW AMPLITUDE TROUGHINESS/WNW FLOW MOVES OVER THE REGION ON WEDNESDAY IN THE MID LEVELS WHILE LOW LEVELS CONTINUE TO ADVECT WARMTH AND MOISTURE. A FEW WEAK EMBEDDED MID LEVEL SHORTWAVES WILL PROVIDE SOME ASCENT THOUGH THE MAIN ENERGY WILL STREAK ACROSS THE NORTHERN FL PENINSULA. LOW END CHANCE/SCT COVERAGE APPEARS WARRANTED. LOW 80S EXPECTED FOR A HIGH TEMP FOR ALL BUT COASTAL LOCALS WHERE JUST ENOUGH ONSHORE COMPONENT EXPECTED TO TEMPER VALUES...MOST PRONOUNCED ALONG BRUNSWICK CTY. BACKDOOR COLD FRONT ENTERS FROM THE NORTH BY ABOUT 06Z WED NIGHT. THIS SHOULD LEAD TO A BRIEF PUSH OF COOLER AND DRIER AIR WHERE PRECIP MAY TAKE A BREAK LATE WEDNESDAY NIGHT. THIS UNDERCUTTING AIRMASS WILL THEN START BEING OVERRUN BY A RENEWED SENSE OF WARM AND MOIST ADVECTION AS THE SOUTHERN BRANCH CUTOFF OPENS UP AND HEADS EAST. THURSDAY WILL BECOME INCREASINGLY UNSETTLED WITH RAIN CHANCES AND MORESO AMOUNTS HIGHLY HINGING UPON SOME MODEL DISCREPANCIES. THE HIGH GFS AMOUNTS APPEAR ON THE HIGH SIDE AND THE FCST FOLLOWS THE DRIER WRF MORE CLOSELY. HIGH RAIN CHANCES ROUND OUT THE PERIOD AS THE UPPER LOW TRANSFERS ENERGY TO LOW PRESSURE DEVELOPING OFF THE COAST. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 3 PM TUESDAY...BEST CHANCE FOR RAIN IN THE PERIOD WILL BE AT THE START OF THE PERIOD AS A SOUTHERN STREAM 5H CUTOFF MOVES ACROSS THE AREA. SURFACE AND UPPER LOW WILL EXIT OFF THE COAST DURING FRI BRINGING AN END TO PRECIP LATE IN THE DAY. WELL BELOW CLIMO TEMPS FRI/FRI NIGHT WITH AREA UNDER THE 5H TROUGH/LOW. TEMPS START TRENDING TO NORMAL SAT AS DEEPER NORTHWEST FLOW DEVELOPS AND THINGS DRY OUT. REMAINDER OF THE PERIOD WILL BE DRY WITH 2 COLD FRONT CROSSING THE AREA LATE IN THE PERIOD. FIRST COLD FRONT PASSES DRY ON MON BUT IS FOLLOWED BY LIMITED COLD ADVECTION AS WINDS QUICKLY BECOME SOUTHERLY AHEAD OF NEXT...MUCH STRONGER COLD FRONT...CROSSING THE AREA TUE. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...SHOWERS AND THUNDERSTORMS WILL BE WEAKENING ACROSS THE INLAND TERMINALS THROUGH 08Z AS THEY CONTINUE E...PERHAPS AS FAR E AS CRE AND MYR AFTER 08Z. MODERATE CONFIDENCE IN IFR STRATUS ALONG THE COAST AFTER 08Z...OTHERWISE MVFR CEILINGS AND OR VISIBILITIES WILL BE LARGELY THE RULE THROUGH SUNRISE. INCREASING PRECIPITABLE WATER VALUES AND CAPES COUPLED WITH HEATING WILL PROVIDE AN ENVIRONMENT CONDUCIVE FOR AT LEAST SCATTERED CONVECTION THIS AFTERNOON. LOOK FOR THE RESULTANT BOUNDARY TO KICK OFF A FEW...WITH MORE SCATTERED CONVECTION INLAND. WINDS WILL BE SOUTHWESTERLY ALL DAY...GUSTY BY MID TO LATE MORNING. EXTENDED OUTLOOK...A GOOD CHANCE OF SHOWERS/EMBEDDED THUNDERSTORMS WITH WIDESPREAD IFR FRIDAY. VFR SATURDAY AND SUNDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM TUESDAY...CONTINUED MINOR ADJUSTMENTS TO WINDS OVERNIGHT...MAINLY CONTINUED DUE TO THE SLOW VEERING OF WIND DIRECTIONS FROM THE S TO SW AS A DIFFUSE WARM FRONT LIFTS ACROSS... AND NORTH OF THE ILM WATERS DURING THE OVERNIGHT. SPEEDS IN GENERAL TO REMAIN 10 TO OCCASIONALLY 15 KT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT THROUGHOUT. A 1 TO 2 FT EASTERLY GROUND SWELL AT 9-11 SECOND PERIODS WILL DOMINATE SIGNIFICANT SEAS...WITH A 1-2 FOOT 3 TO 5 SECOND PERIOD WIND DRIVEN CHOP ADDING A FOOT OR 2 TO THE OVERALL SIG. SEAS. COULD POSSIBLY SEE A FEW 4 FOOTERS ACROSS THE SHALLOW SHOALS OFF CAPE FEAR BUT CONTINUED NOT ENOUGH OF AN OCCURRENCE TO PLACE IN THE CWF. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... AS OF 3 PM TUESDAY...PREFRONTAL FLOW REGIME CRANKS UP AS WEDNESDAY PROGRESSES AND THE GRADIENT BECOMES PINCHED BETWEEN WEST ATLANTIC HIGH AND THE APPROACHING BOUNDARY. WEDNESDAY NIGHT THIS MODERATELY STRONG WIND FIELD WILL START VEERING WITH THE APPROACH OF THE BOUNDARY. BEING A BACKDOOR COLD FRONT RATHER THAN A MORE CLASSICAL BOUNDARY COMING IN FROM THE NORTHWEST THIS FRONT WILL MAKE FAIRLY SLOW PROGRESS SOUTHWARD EARLY THURSDAY. THIS MEANS THAT THE NORTHERN AND SOUTHERN ZONES WILL SPEND SEVERAL HOURS SPLIT BETWEEN THE NE AND THE SW WINDS ON EITHER SIDE OF THE BOUNDARY. FURTHER COMPLICATING MATTERS IS THAT THERE IS UNCERTAINTY REGARDING THE TRACK AND STRENGTH OF A LOW EXPECTED TO MOVE WEST TO EAST ACROSS THE REGION. TOUGH TO SAY WHETHER OR NOT SEAS BUILD INTO ADVISORY REALM AT ANY TIME DURING THE PERIOD BUT AN EXTENDED STRETCH OF SCEC HEADLINES APPEARS LIKELY. LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 3 PM TUESDAY...STRONG NORTHEAST FLOW OVER THE WATERS FRI/FRI NIGHT WITH GRADIENT PINCHED BETWEEN EXITING SURFACE LOW AND HIGH BUILDING DOWN THE COAST. HEADLINES WILL LIKELY BE REQUIRED FRI FOR ALL WATERS. GRADIENT STARTS TO RELAX SAT BUT HEADLINES WILL LIKELY CARRY OVER INTO THE EVENING BEFORE SEAS DROP BELOW SCA THRESHOLDS. SURFACE RIDGE AXIS REMAINS WEST OF THE WATERS EARLY SUN...WITH NORTHEAST FLOW CONTINUING OVER THE WATERS. HOWEVER...SPEEDS WILL BE MUCH LESS THAN FRI/SAT...10 TO 15 KT INSTEAD OF 20 TO 25 KT. APPROACHING COLD FRONT LATE IN THE PERIOD WILL RESULT IN WINDS BECOMING SOUTHERLY SUN AFTERNOON...THOUGH GRADIENT REMAINS WEAK. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...HOEHLER SHORT TERM...BACON LONG TERM...LEBO AVIATION...LOEWENTHAL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
208 AM EDT WED APR 4 2012 .SYNOPSIS... LOW PRESSURE WILL MOVE THROUGH THE REGION TONIGHT...WITH THUNDERSTORMS DEVELOPING UNTIL TOMORROW MORNING. HIGH PRESSURE WILL GRADUALLY MOVE IN FROM THE NORTH THROUGH THE END OF THE WEEK...WITH GRADUALLY COOLING TEMPERATURES. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AIRMASS ACROSS OUR AREA REMAINS JUST SLIGHTLY UNSTABLE AND THIS IS GENERALLY ALOFT AS BOUNDARY LAYER HAS COOLED/DRIED IN THE WAKE OF EARLIER OUTFLOW BOUNDARY. A LINE OF SHOWERS AND THUNDERSTORMS IS CONTINUING ALONG THE COLD FRONT BACK ACROSS CENTRAL ILLINOIS INTO NORTHERN INDIANA...BUT SO FAR THESE HAVE HAD A TOUGH TIME PROGRESSING EASTWARD. THE LATEST HRRR IS SHOWING THIS PCPN PUSHING EAST INTO OUR NORTHERN AREAS THROUGH 06Z...BUT GIVEN TRENDS AND MORE STABLE AIRMASS ACROSS OUR AREA...NOT SURE IF THAT WILL PAN OUT. AS LOW OVER MISSOURI PUSHES EAST THROUGH THE OVERNIGHT HOURS...WE SHOULD BEGIN TO MOISTEN UP A BIT MORE AND PERHAPS DESTABILIZE ALOFT A LITTLE BETTER. WILL MAKE SOME DOWNWARD ADJUSTMENTS TO POPS IN THE NEAR TERM AND BRING BETTER POPS IN FROM THE SOUTHWEST LATER TONIGHT. SEVER THREAT SEEMS TO BE RATHER LOW GIVEN BOTH WEAK SHEAR PROFILES AND WEAK INSTABILITY. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... THE SOUTHERN HALF OF THE CWA WILL START THE DAY WEDNESDAY IN A FAVORABLE CONVERGENT AREA FOR CONTINUED SHOWER AND THUNDERSTORM DEVELOPMENT. THIS WILL DIMINISH AS THE SURFACE FRONT PUSHES SOUTH OF THE FORECAST AREA DURING THE AFTERNOON...BEGINNING A PATTERN OF NORTH WINDS AND COLD ADVECTION THAT WILL GO THROUGH THE END OF THE WEEK. MOISTURE WILL REMAIN JUST SOUTH OF THE FORECAST AREA...AND MAY ACTUALLY EDGE NORTH ENOUGH TO PRODUCE SOME PRECIPITATION IN THE FAR SOUTH ON THURSDAY. THIS WILL BE POSSIBLE AS A WEAKENING CLOSED UPPER LOW MOVES EAST INTO THE TENNESSEE VALLEY. OVERALL...HOWEVER...A DRIER AND COOLER AIR MASS WILL BE THE RESULT OF THIS SHIFT IN THE WEATHER PATTERN. TEMPERATURES...THUS...SHOULD COOL THROUGH THE FORECAST PERIOD. THIS WILL RESULT IN MIN TEMPERATURES GETTING VERY CLOSE TO FREEZING ON THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... BEGINNING OF PERIOD WILL BE MARKED BY AN AMPLIFIED UPPER LEVEL FLOW PATTERN. UPPER LOW THAT HAD BEEN TREKKING ACROSS THE MID SOUTH WILL BE ABSORBED INTO AN EAST COAST TROUGH. SHARP RIDGING OVER THE PLAINS WILL PLACE THE LOCAL AREA IN NORTHERLY FLOW ALOFT. AT THE SFC...HIGH PRESSURE WILL BUILD SOUTHWARD FROM ONTARIO INTO THE GREAT LAKES. THIS WILL LEAD TO DRY AND SEASONABLE CONDITIONS FOR FRIDAY. ON FRIDAY NIGHT...THE SFC HIGH WILL BUILD OVERHEAD...LEADING TO CLEAR SKIES AND LIGHT WINDS. FROST WILL BE A CONCERN OVER MUCH OF THE CWA EXCEPT PERHAPS NORTHERN KY...AND THE TYPICAL COOLER LOCALES EAST OF COLUMBUS MAY APPROACH FREEZING (THESE TEMPERATURES REPRESENT A DOWNWARD ADJUSTMENT FROM THE PREVIOUS FORECAST). AS THE HIGH SLIDES EAST OF THE AREA ON SATURDAY...WINDS WILL BECOME SOUTHERLY AND PROMOTE TEMPERATURES TO RISE A LITTLE ABOVE NORMAL. THE NEXT SHORT WAVE TROUGH TO APPROACH FROM THE ROCKIES WILL MAINLY SERVE TO SQUASH THE UPPER RIDGE...WITH MOST OF THE ENERGY REMAINING NORTH OF THE AREA. A SFC LOW WILL TRACK WELL NORTH INTO CANADA...WITH A TRAILING COLD FRONT CROSSING THE AREA ON SUNDAY. MODELS DISAGREE A LITTLE ON TIMING...BUT APPEARS TO BE MAINLY A DAYTIME EVENT...SO DELAYED POPS A LITTLE FROM PREVIOUS FORECAST. IN WESTERLY FLOW THROUGHOUT THE ATMOSPHERE...THE FRONT WILL BE MOISTURE STARVED...SO MAINTAINED THE LOW CHANCE POPS. INSTBY WILL BE WEAK BUT PRESENT (MORESO SOUTH)...SO KEPT THUNDER MENTION. AIRMASS CHANGE BEHIND THE FRONT WILL BE MINIMAL AS WEAK SFC RIDING EXTENDS INTO THE AREA BY SUNDAY NIGHT INTO EARLY MONDAY...WITH TEMPERATURES REMAINING SLIGHTLY ABOVE NORMAL. AS UPPER LEVEL GYRE FORMS OVER EASTERN CANADA...ANOTHER SHORTWAVE TROUGH WILL ROTATE DOWN THROUGH THE AREA LATE MONDAY INTO TUESDAY. THIS SYSTEMS WILL BE MOISTURE STARVED AS WELL...SO LIMITED FORECAST TO CHANCE POPS. LEFT THUNDER MENTION OUT WITH LIMITED INSTBY AND HIGHER THETA-E SUPPRESSED FAR TO OUR SOUTH. WHILE MODELS DIFFER WITH TIMING AND EXACT FEATURES...THEY AGREE ON THE MORE SUBSTANTIAL EFFECT FROM THIS SYSTEM...WHICH WILL BE THE COLDER AIR IT PULLS SOUTHWARD INTO THE AREA. FORECAST HIGH TEMPERATURES ON TUESDAY ARE ABOUT 10 DEGREES BELOW NORMAL. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... COLD FRONT WHICH IS ORIENTED W-E FROM NEAR KSTL TO JUST SOUTH OF KIND TO NEAR KDAY TO SAG SLOWLY SOUTH THRU THIS MORNING. SCATTERED THUNDERSTORMS WILL DEVELOP THIS MORNING IN THE MARGINALLY UNSTBL AIR AHD OF A WAVE OF LOW PRESSURE TRACKING ALONG THIS FRONTAL BOUNDARY. WITH THE SOUTHWARD PUSH OF THE FRONT...EXPECT THE BEST CHANCE FOR THUNDERSTORMS TO BE ACROSS KCVG/KLUK. WILL THEREFORE MENTION PREVAILING PRECIP AT KCVG/KLUK AND TEMPO AT KDAY AND LIMIT MENTION TO VCTS AT KCMH/KLCK. PCPN SHOULD TAPER OFF FROM NORTH TO SOUTH THROUGH LATE MORNING. GOOD CAA IN THE WAKE OF THE FRONT MAY LEAD TO A PERIOD OF MVFR CIGS...BEFORE DRIER AIR IS ABLE TO WORK IN FROM THE NORTH ALLOWING CONDITIONS TO BECOME VFR. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...JGL SHORT TERM...HATZOS LONG TERM...SNYDER AVIATION...AR
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
637 AM CDT WED APR 4 2012 .AVIATION... CONDITIONS SHOULD REMAIN LARGELY VFR FOR ALL TAF SITES. THE EXCEPTION MAY BE KHOT AND KM89 FOR A BRIEF PERIOD THIS MORNING...AND ALSO ANY TAF SITES AFFECTED BY SHOWERS LATER THIS MORNING. DEWPOINT DEPRESSIONS ARE VERY SMALL AT THOSE SITES AND KHOT IS SHOWING FEW-SCT003 BASES. THEY ARE RIGHT ON THE CUSP OF DEVELOPING SOME FOG OR LOW CLOUDS SO HAVE THROWN A TEMPO FOR 4SM AND SCT003 AT THOSE TWO TERMINALS. OTHERWISE...HAVE TRENDED TOWARDS RUC GUIDANCE WHICH SHOWS SHOWERS DEVELOPING FROM ROUGHLY KFYV DOWN TO KELD BEFORE 14Z...THEN SHIFTING EAST OF ALL TERMINALS BY 18Z OR SO. NOT TERRIBLY CONFIDENT IN HOW MUCH REDEVELOPMENT OF SHOWER ACTIVITY WE ARE GOING TO SEE TODAY SO ONLY INCLUDED MENTION OF VCSH AT TERMINALS FOR A SHORT PERIOD THIS MORNING. WINDS WILL GRADUALLY TURN WSW THROUGH THE DAY AS THE FRONT PASSES THROUGH. LOOKS LIKE THERE SHOULD BE ENOUGH DRY AIR TO PRECLUDED FOG OR LOW CLOUDS TONIGHT. && .PREV DISCUSSION... /ISSUED 333 AM CDT WED APR 4 2012/ SHORT RANGE...TODAY THROUGH SATURDAY NIGHT MODELS REMAIN IN BASICALLY GOOD AGREEMENT THIS MORNING DEPICTING A SLOW MOVING UPPER LOW AND ASSOCIATED FRONTAL BOUNDARY MOVING ACROSS THE FORECAST AREA. GFS/ECMWF COMBO PREFERRED THIS MORNING WITH NAM SOLUTION INITIATING POORLY AND AS SUCH DISCOUNTED. CLOSED OFF UPPER LOW OVER THE TEXAS/OKLAHOMA PANHANDLES SHOWING UP CLEARLY ON MOISTURE CHANNEL IMAGERY THIS MORNING. SYSTEM REMAINS CUT OFF FROM THE PREVAILING FLOW AND WILL DRIFT SLOWLY EASTWARD ACROSS THE NORTHERN PART OF THE STATE OVER THE NEXT DAY OR SO...AND NOT EXPECTED TO CLEAR THE STATE UNTIL THURSDAY AFTERNOON. ASSOCIATED SURFACE BOUNDARY CURRENTLY OVER EASTERN OKLAHOMA AND ALSO EXPECTED TO TAKE ITS TIME GETTING THROUGH THE STATE...LIKELY NOT CLEARING THE MISSISSIPPI RIVER UNTIL LATE WEDNESDAY NIGHT/EARLY THURSDAY MORNING. UPPER IMPULSE MOVING THROUGH THE REGION THIS MORNING CONTINUES TO PRODUCE SCATTERED SHOWERS BUT OVERALL AREA CONTINUES TO DECREASE IN AREAL COVERAGE. STRONGEST CONVECTION REMAINS TO THE SOUTH OF THE FORECAST AREA BUT ISOLATED THUNDER CANNOT BE RULED OUT THIS MORNING ESPECIALLY ACROSS THE SOUTHERN COUNTIES. NEXT IMPULSE WILL MOVE THROUGH THE BASE OF THE UPPER LOW DURING THE AFTERNOON. JET DYNAMICS ASSOCIATED WITH THE WAVE WILL LIKELY LEAD TO ADDITIONAL CONVECTIVE DEVELOPMENT ALONG AND TO THE EAST OF THE AFOREMENTIONED SURFACE BOUNDARY WHICH SHOULD LIKELY BE OVER THE EASTERN THIRD OF THE FORECAST AREA. CAN NOT RULE OUT SOME STRONGER STORMS OVER THIS AREA. PRECIPITATION CHANCES WILL BE LESS FURTHER TO THE EAST AS DRIER AIR MOVES IN. UPPER LOW MOVES ACROSS THE NORTH TONIGHT AND THURSDAY WITH ANOTHER IMPULSE ROTATING THROUGH ITS BASE. THE RESULT WILL BE ANOTHER CHANCE OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS WITH THE BEST CHANCES OVER THE NORTH CLOSER TO THE UPPER LOW. SYSTEM FINALLY CLEARS THE STATE BY THURSDAY EVENING WITH HIGH PRESSURE BUILDING IN BEHIND THE DEPARTING LOW WITH DRY CONDITIONS EXPECTED FRIDAY. NEXT COLD FRONT WILL APPROACH THE STATE DURING THE DAY SATURDAY. GFS KEEPS AREA DRY BUT ECMWF DOES PAINT A LITTLE QPF OVER THE NORTHWEST ZONES LATE IN THE DAY. OVERALL SPEED OF THE FRONT A LITTLE SLOWER AND WILL TRIM BACK POPS TO THE NORTHWEST SATURDAY AND AREA WIDE SATURDAY NIGHT AS BOUNDARY WILL BE BISECTING THE STATE FROM NORTHEAST TO SOUTHWEST BY THE END OF THE PERIOD. REGARDLESS...POPS WILL ONLY BE SLIGHT CHANCE TO LOW END CHANCE AS SYSTEM NOT VERY IMPRESSIVE. TEMPERATURES WILL BE TRICKY TODAY DEPENDING ON WHERE THE FRONT ENDS UP ALONG WITH PRECIP AND CLOUD COVER COMING INTO PLAY. WARMEST DAY STILL LOOKS TO BE TODAY WITH TEMPERATURES RETURNING TO NEAR NORMAL FOR THE REMAINDER OF THE PERIOD. MAV/MEX NUMBERS LOOK REASONABLE AND ARE GENERALLY ACCEPTED. LONG TERM...SUNDAY THROUGH TUESDAY... A COLD FRONT WILL SWEEP THROUGH THE STATE ON SUNDAY AS AN UPPER RIDGE BUILDS OVER THE HIGH PLAINS AND A TROUGH OVER THE EASTERN CONUS. REALLY DO NOT EXPECT MUCH IN THE WAY OF PRECIP AS RETURN FLOW WILL BE WEAK OR NON-EXISTENT IN THE DAYS LEADING UP TO SUN...AND UPPER SUPPORT SHOULD BE WELL REMOVED TO THE NORTH. THE COLD FRONT WILL STALL OUT TO THE SOUTH AND WEST OF THE STATE LATER IN THE PERIOD. PREVIOUS SHIFTS HAD SOME SLIGHT CHANCE POPS...MAINLY IN THE SOUTHWEST...ON MONDAY. WILL LEAVE THIS AS-IS DUE TO SHORTWAVE ENERGY ROTATING THROUGH EITHER NEAR ARKANSAS...OR OVERHEAD DEPENDING ON WHICH MODEL YOU BELIEVE. DID REMOVE PRECIP MENTION ON MONDAY NIGHT THOUGH AS LOSS OF DAYTIME HEATING AND WHAT MARGINAL UPPER SUPPORT WAS PRESENT SHOULD MEAN ANY SHOWER WOULD DIE A QUICK DEATH. AS FOR TEMPERATURES...THEY WILL BE MUCH CLOSER TO NORMAL VALUES VERSUS WHAT HAS BEEN SEEN LATELY. HIGHS FROM THE LOW 70S NORTH TO THE MID/UPPER 70S IN THE SOUTH WILL BE THE NORM. LOWS WILL BE IN THE LOW TO MID 50S INITIALLY...PERHAPS DIPPING INTO THE UPPER 30S TO LOW 40S IN THE NORTH BY MONDAY/TUESDAY NIGHTS. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 79 55 73 48 / 50 30 40 10 CAMDEN AR 81 54 78 53 / 40 20 20 10 HARRISON AR 76 52 72 46 / 40 30 40 10 HOT SPRINGS AR 79 54 75 53 / 40 20 30 10 LITTLE ROCK AR 80 55 76 53 / 40 30 30 10 MONTICELLO AR 82 56 79 54 / 50 20 20 10 MOUNT IDA AR 78 53 75 52 / 30 20 30 10 MOUNTAIN HOME AR 77 53 72 47 / 40 40 40 10 NEWPORT AR 79 55 74 49 / 50 40 40 10 PINE BLUFF AR 81 56 78 54 / 50 30 30 10 RUSSELLVILLE AR 78 53 74 50 / 40 30 30 10 SEARCY AR 80 55 75 50 / 50 30 30 10 STUTTGART AR 81 56 77 53 / 50 30 30 10 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AVIATION...64
AREA FORECAST DISCUSSION
NWS MIAMI FL
1005 AM EDT WED APR 4 2012 .UPDATE...THE SHORT TERM FORECAST REMAINS ON TRACK WITH NO APPRECIABLE CHANGES NEEDED. THE 12Z MFL SOUNDING CONTINUES TO SHOW CONSIDERABLE DRY AIR IN THE MID AND UPPER LEVELS. HOWEVER, WITH SIGNIFICANT DAYTIME HEATING AND JUST ENOUGH MOISTURE, A FEW ISOLATED SHOWERS OR THUNDERSTORMS COULD FORM THIS AFTERNOON, ESPECIALLY AS THE SEA BREEZE MOVES INLAND. TEMPERATURES WILL REMAIN ABOVE NORMAL, PEAKING IN THE UPPER 80S TO LOWER 90S AND APPROACHING RECORD HIGHS AT A FEW LOCATIONS. && .PREV DISCUSSION... /ISSUED 732 AM EDT WED APR 4 2012/ AVIATION... VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE PERIOD. SOUTHERLY FLOW WILL PREVAIL THROUGH THE AFTERNOON HOURS AROUND 10-12 KTS AT ALL SITES EXCEPT KAPF WHERE A WEST TO SOUTHWEST SEA BREEZE SHOULD SET UP AGAIN THIS AFTERNOON. LIGHT WINDS ARE EXPECTED TONIGHT. PATCHY FOG MAY BE POSSIBLE THURSDAY MORNING...BUT PROBABILITY IS TOO LOW TO MENTION AT THIS TIME. PREV DISCUSSION... /ISSUED 448 AM EDT WED APR 4 2012/ .FEW STRONG THUNDERSTORMS POSSIBLE THIS AFTERNOON, THU AFTERNOON, AND FRIDAY WITH LOW PROBABILITIES OF SEVERE... .HOT THROUGH FRIDAY, THEN COOLER AND DRIER THIS WEEKEND-NEXT WEEK... DISCUSSION...WATER VAPOR IMAGERY SHOWS A MID/UPPER LEVEL LOW SPINNING OVER THE TEXAS/OKLAHOMA PANHANDLE REGION WITH WEST SOUTHWEST FLOW PREDOMINATING ACROSS THE GULF AND ACROSS FLORIDA. BOTH GFS AND ECMWF SHOW THIS UPPER LOW MOVING ACROSS THIS MID SOUTH ON THU...THEN OPENING UP AND MERGING WITH A TROUGH WHICH WILL AMPLIFY ACROSS NEW ENGLAND AND THE MID ATLANTIC STATES ON FRIDAY. LOW PRESSURE WILL DEVELOP NEAR THE CAROLINA COAST MOVING INTO THE ATLANTIC FRIDAY WITH A TRAILING COLD FRONT SWEEPING ACROSS SOUTH FLORIDA FRIDAY EVENING. AHEAD OF THIS FRONT, THE AIRMASS WILL CONTINUE FAIRLY DRY WITH FORECAST SOUNDINGS SHOWING PWAT VALUES OF 1-1.2 INCHES TODAY RISING TO 1.3-1.5 LATE THU-FRI. IT WILL BE UNSTABLE EACH AFTERNOON THROUGH FRIDAY. GOES SOUNDER DATA SHOWS H5 TEMPS NOW IN THE -12 TO -13C RANGE OVER SOUTH FLORIDA. FCST SOUNDINGS SHOW EVEN SLIGHT COOLING TO -14C BY EVENING WITH LI`S FALLING TO AROUND -7C AND CAPE NEARING 2000 J/KG LATE IN THE DAY. GIVEN LACK OF MOISTURE...ONLY HAVE SLIGHT CHC POPS INTERIOR-EAST. IT`S POSSIBLE THAT NOTHING DEVELOPS THIS AFTERNOON...BUT THERE MAY BE JUST ENOUGH MOISTURE TO ALLOW A FEW TSTORMS TO DEVELOP. HRRR INDEED DOES SHOW ISOLATED DEVELOPMENT INTERIOR/EAST COAST THIS AFTERNOON. GIVEN THE STRONG HEATING TODAY AND COLD AIR ALOFT, ONE OR TWO PULSE STRONG TSTORMS WILL BE POSSIBLE INTERIOR-EAST, CAPABLE OF PRODUCING GUSTY WINDS UP TO 50 MPH ALONG WITH HAIL AND FREQUENT LIGHTNING STRIKES. AS MOISTURE INCREASES A TAD THURSDAY AFTERNOON, THE RISK OF TSTORMS INCREASES. SW STEERING FLOW WILL LEAD TO CONVERGENCE ACROSS THE EAST COAST METRO AREAS, SO SCATTERED TSTORMS ARE EXPECTED EAST COAST METRO WITH A SLIGHT CHANCE ELSEWHERE. THEN ON FRIDAY THERE WILL BE A CHANCE OF THUNDERSTORMS AREA WIDE ALONG/AHEAD OF THE COLD FRONT. STABILITY INDICES SHOW THAT IT WILL CONTINUE TO BE QUIET UNSTABLE, PARTICULARLY ON THURSDAY AFTERNOON. HOWEVER, THE BETTER DYNAMICS WILL BE ON FRIDAY. STRONG TSTORMS WILL BE POSSIBLE EACH DAY WITH LOW PROBABILITIES OF SEVERE. CURRENT ASSESSMENT SUGGESTS THAT THE GREATEST POTENTIAL FOR ISOLATED SEVERE THUNDERSTORMS IS THURSDAY AFTERNOON EAST COAST METRO...DUE TO WEAKER FLOW ON THIS DAY, BETTER SURFACE CONVERGENCE AND HIGH INSTABILITY. HOT DAYS WILL PREVAIL THROUGH FRIDAY WITH HIGHS TOPPING 90 MOST INLAND LOCALES AND NEAR 90 EAST. CONSENSUS GUIDANCE WAS TOO COOL FOR MAXES NEXT FEW DAYS...SO FOLLOWED A NAM12-GFS BLEND. THE COLD FRONT WILL MOVE ACROSS SOUTH FL FRIDAY EVENING, BRINGING IN A COOL AIRMASS FOR APRIL STANDARDS WITH HIGHS IN THE UPPER 70S TO LOWER 80S AND DEWPOINTS FALLING INTO THE 50S THIS WEEKEND. NIGHTTIME LOWS WILL FALL INTO THE 50S INTERIOR AND 60S COASTS. THIS COOLER TREND WILL CONTINUE NEXT WEEK...WITH BOTH GFS/ECMWF SHOWING A RE- ENFORCING SHOT OF COOLER AIR FROM THE NORTH MID WEEK. THIS WILL KEEP TEMPS/HUMIDITY IN CHECK THROUGH NEXT WEEK WITH COMFORTABLE WEATHER PREVAILING AND DRY WEATHER EXPECTED. MARINE...NO CONCERNS IN THE NEAR TERM, BUT WINDS/SEAS WILL INCREASE, ESPECIALLY IN THE GULF STREAM BEHIND THE COLD FRONT FRI EVENING AS WINDS BECOME NE AND INCREASE. FIRE WEATHER...RELATIVE HUMIDITIES FELL INTO THE MID 20S TO LOWER 30S OVER A LARGE PORTION OF INTERIOR SOUTH FL YESTERDAY. TODAY, LOW RH`S OF BELOW 35 PERCENT FOR 4 HR OR MORE ARE FORECAST FOR THE LAKE OKEECHOBEE REGION AND INLAND COLLIER AND INLAND BROWARD COUNTIES...SO WILL BE ISSUING A FIRE DANGER STMT FOR THESE LOCALES. MOISTURE WILL INCREASE ON THU-FRI WITH MODIFYING RH`S THEN. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 71 89 72 / 20 10 40 40 FORT LAUDERDALE 88 72 89 73 / 10 10 30 30 MIAMI 88 72 89 73 / 10 10 30 30 NAPLES 85 69 85 71 / - 10 20 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ UPDATE...14/MJB
AREA FORECAST DISCUSSION
NWS MIAMI FL
732 AM EDT WED APR 4 2012 .AVIATION... VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE PERIOD. SOUTHERLY FLOW WILL PREVAIL THROUGH THE AFTERNOON HOURS AROUND 10-12 KTS AT ALL SITES EXCEPT KAPF WHERE A WEST TO SOUTHWEST SEA BREEZE SHOULD SET UP AGAIN THIS AFTERNOON. LIGHT WINDS ARE EXPECTED TONIGHT. PATCHY FOG MAY BE POSSIBLE THURSDAY MORNING...BUT PROBABILITY IS TOO LOW TO MENTION AT THIS TIME. && .PREV DISCUSSION... /ISSUED 448 AM EDT WED APR 4 2012/ ..FEW STRONG THUNDERSTORMS POSSIBLE THIS AFTERNOON, THU AFTERNOON, AND FRIDAY WITH LOW PROBABILITIES OF SEVERE... ..HOT THROUGH FRIDAY, THEN COOLER AND DRIER THIS WEEKEND-NEXT WEEK... DISCUSSION...WATER VAPOR IMAGERY SHOWS A MID/UPPER LEVEL LOW SPINNING OVER THE TEXAS/OKLAHOMA PANHANDLE REGION WITH WEST SOUTHWEST FLOW PREDOMINATING ACROSS THE GULF AND ACROSS FLORIDA. BOTH GFS AND ECMWF SHOW THIS UPPER LOW MOVING ACROSS THIS MID SOUTH ON THU...THEN OPENING UP AND MERGING WITH A TROUGH WHICH WILL AMPLIFY ACROSS NEW ENGLAND AND THE MID ATLANTIC STATES ON FRIDAY. LOW PRESSURE WILL DEVELOP NEAR THE CAROLINA COAST MOVING INTO THE ATLANTIC FRIDAY WITH A TRAILING COLD FRONT SWEEPING ACROSS SOUTH FLORIDA FRIDAY EVENING. AHEAD OF THIS FRONT, THE AIRMASS WILL CONTINUE FAIRLY DRY WITH FORECAST SOUNDINGS SHOWING PWAT VALUES OF 1-1.2 INCHES TODAY RISING TO 1.3-1.5 LATE THU-FRI. IT WILL BE UNSTABLE EACH AFTERNOON THROUGH FRIDAY. GOES SOUNDER DATA SHOWS H5 TEMPS NOW IN THE -12 TO -13C RANGE OVER SOUTH FLORIDA. FCST SOUNDINGS SHOW EVEN SLIGHT COOLING TO -14C BY EVENING WITH LI`S FALLING TO AROUND -7C AND CAPE NEARING 2000 J/KG LATE IN THE DAY. GIVEN LACK OF MOISTURE...ONLY HAVE SLIGHT CHC POPS INTERIOR-EAST. IT`S POSSIBLE THAT NOTHING DEVELOPS THIS AFTERNOON...BUT THERE MAY BE JUST ENOUGH MOISTURE TO ALLOW A FEW TSTORMS TO DEVELOP. HRRR INDEED DOES SHOW ISOLATED DEVELOPMENT INTERIOR/EAST COAST THIS AFTERNOON. GIVEN THE STRONG HEATING TODAY AND COLD AIR ALOFT, ONE OR TWO PULSE STRONG TSTORMS WILL BE POSSIBLE INTERIOR-EAST, CAPABLE OF PRODUCING GUSTY WINDS UP TO 50 MPH ALONG WITH HAIL AND FREQUENT LIGHTNING STRIKES. AS MOISTURE INCREASES A TAD THURSDAY AFTERNOON, THE RISK OF TSTORMS INCREASES. SW STEERING FLOW WILL LEAD TO CONVERGENCE ACROSS THE EAST COAST METRO AREAS, SO SCATTERED TSTORMS ARE EXPECTED EAST COAST METRO WITH A SLIGHT CHANCE ELSEWHERE. THEN ON FRIDAY THERE WILL BE A CHANCE OF THUNDERSTORMS AREA WIDE ALONG/AHEAD OF THE COLD FRONT. STABILITY INDICES SHOW THAT IT WILL CONTINUE TO BE QUIET UNSTABLE, PARTICULARLY ON THURSDAY AFTERNOON. HOWEVER, THE BETTER DYNAMICS WILL BE ON FRIDAY. STRONG TSTORMS WILL BE POSSIBLE EACH DAY WITH LOW PROBABILITIES OF SEVERE. CURRENT ASSESSMENT SUGGESTS THAT THE GREATEST POTENTIAL FOR ISOLATED SEVERE THUNDERSTORMS IS THURSDAY AFTERNOON EAST COAST METRO...DUE TO WEAKER FLOW ON THIS DAY, BETTER SURFACE CONVERGENCE AND HIGH INSTABILITY. HOT DAYS WILL PREVAIL THROUGH FRIDAY WITH HIGHS TOPPING 90 MOST INLAND LOCALES AND NEAR 90 EAST. CONSENSUS GUIDANCE WAS TOO COOL FOR MAXES NEXT FEW DAYS...SO FOLLOWED A NAM12-GFS BLEND. THE COLD FRONT WILL MOVE ACROSS SOUTH FL FRIDAY EVENING, BRINGING IN A COOL AIRMASS FOR APRIL STANDARDS WITH HIGHS IN THE UPPER 70S TO LOWER 80S AND DEWPOINTS FALLING INTO THE 50S THIS WEEKEND. NIGHTTIME LOWS WILL FALL INTO THE 50S INTERIOR AND 60S COASTS. THIS COOLER TREND WILL CONTINUE NEXT WEEK...WITH BOTH GFS/ECMWF SHOWING A RE- ENFORCING SHOT OF COOLER AIR FROM THE NORTH MID WEEK. THIS WILL KEEP TEMPS/HUMIDITY IN CHECK THROUGH NEXT WEEK WITH COMFORTABLE WEATHER PREVAILING AND DRY WEATHER EXPECTED. MARINE...NO CONCERNS IN THE NEAR TERM, BUT WINDS/SEAS WILL INCREASE, ESPECIALLY IN THE GULF STREAM BEHIND THE COLD FRONT FRI EVENING AS WINDS BECOME NE AND INCREASE. FIRE WEATHER...RELATIVE HUMIDITIES FELL INTO THE MID 20S TO LOWER 30S OVER A LARGE PORTION OF INTERIOR SOUTH FL YESTERDAY. TODAY, LOW RH`S OF BELOW 35 PERCENT FOR 4 HR OR MORE ARE FORECAST FOR THE LAKE OKEECHOBEE REGION AND INLAND COLLIER AND INLAND BROWARD COUNTIES...SO WILL BE ISSUING A FIRE DANGER STMT FOR THESE LOCALES. MOISTURE WILL INCREASE ON THU-FRI WITH MODIFYING RH`S THEN. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 71 89 72 / 20 10 40 40 FORT LAUDERDALE 88 72 89 73 / 10 10 30 30 MIAMI 88 72 89 73 / 10 10 30 30 NAPLES 85 69 85 71 / - 10 20 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...14/MJB AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION...updated for aviation discussion
NWS TALLAHASSEE FL
532 AM EDT Wed Apr 4 2012 ...SEVERE STORMS ARE POSSIBLE TODAY AND LIKELY ON THURSDAY... ...COOLER TEMPERATURES ON TAP BY THE WEEKEND... .SYNOPSIS... Rainfall assocd with Tuesday`s MVC has effectively dissipated. However we are keeping an eye on outflow generated convection moving east across coast wrn panhandle. Expect some fog to linger this morning especially west of the Apalachicola River but advancing clouds decks limiting dense fog witnessed previous two nights. AT UPPER LEVELS... The large scale split flow longwave pattern commences rather amplified with well established blocking pattern. This is highlighted in nrn stream by ridge over Nrn Plains to Cntrl Canada anchored by troughs across extreme Ern PAC/West Coast and NE states. In Srn stream, ridge over Srn CA/Desert SW, trough over Srn Plains with very slow moving cutoff low Srn High Plains then weak ridging ewd to Ern seaboard with axis from NE SEWD to Srn FL. It is the low that will be our next major weather maker on Thurs. During the rest of the period, Low is expected to slowly move to Srn MO by sunrise Thurs then across Cntrl Gulf Region by aftn and around base of Ern trough into Thurs night then out into Atlc early Fri increasingly flattening Ern ridge. A series of shortwaves will eject Ewd from low sparking convection. Today, one currently across OH Valley will move SEWD towards KY reaching mid-Atlc late tonight while a second impulse will move across Srn AL/GA later today. AT LOWER LEVELS... Main features are high off Cntrl FL coast with ridge WSW across Cntrl FL and Gulf of Mex. 1005mb low over ern OK/KS border with warm front ENE to mid-Atlc states and cold front swd thru ern OK/ern TX and into Gulf. During the rest of the period, under influence of upper low, surface reflection will strengthen and move east thru AL by Thurs aftn dragging cold front SEWD. This low will track slowly into the Carolinas on Fri before moving offshore. WSW-ENE oriented front will move from LA/MS early Thurs morning to across SE AL/SW GA/FL Panhandle during the afternoon and will exit our area Thurs night into early Fri. Ahead of these systems, with substantial low level moisture and no capping, the airmass is expected to be warm and unstable with dewpoints in the mid 60s and a wide area of SBCAPE values between 1500-2000 j/kg. Mid level lapse rates are also forecast to be fairly steep around 6.5-7.0 C/km. Deep layer shear values with generally WLY low level flow from the GFS and NAM are forecast to be between 30 and 40 knots with 0-1 km shear around 20 knots. Guidance suggests a 60 kt H5 speed max across srn AL by sundown. Although widespread severe weather is not likely, instability indices point to strong to severe storms on Thurs and Thurs evening. In wake of front, large surface high builds ESE from MS Valley to SE Coast. Another shortwave diving into the Ern trough will bring a reinforcing shot of colder and drier air that overspreads the region thru the weekend and beyond. .SHORT TERM...(Today through Friday)... TODAY...Overnight radar shows apparent MCS over MS some of which will work its way EWD later today. Also various outflow boundaries linger from yesterday`s storms and could serve as focus for storms today. One noted across W/Cntrl AL during predawn hours will move east into worked over area and weaken but still may help ignite storms later today. Also weak shortwave is expected to move across mainly Srn GA later during time of max heating when RUC sounding PWATs around 1.4 inches and capes around 2800 j/kg. All this could spark another bout of showers and thunderstorms especially over GA counties. 40-10% NE-SW POP gradient. Some storms may again be strong to isold severe with locally heavy rain, especially if sun breaks out to enhance diurnal heating allowing aftn temps to rise. However will not use enhanced wording in grids as local severe wx tool with only 2% chance and local CAM with essentially zero with CIN -7 to -10 especially over FL. TONIGHT...Afternoon convection will persist past sundown. 40-10% NE-SE POP gradient. Local severe wx tool with up to 7% chance of severe wx mainly wrn counties. THURSDAY...70-60% N-S POP gradient. Guidance indicates that ample convection will exist across wrn third of CWA early focused by warm advection along surface boundary. Some will likely be at least isold severe. Since wind fields will be largely unidirectional, focus will be on bowing lines with damaging wind. However, temperatures should remain sufficiently cool for large hail. This overlays well with local severe wx tool with 25-5% SW- NE gradient of chances of severe wx in morning. Later in the day, activity will switch ewd but how strong this convection will be will depend in part on how much instability remains and impact of clouds on downstream insolation. Still, combination of approaching upper low, next shortwave, strengthening surface low and cold front should generate organized storms moving from MS into AL then GA in aftn with a continued threat of damaging winds and large hail. Local severe wx tool with 15-20% chance of severe wx. SPC has placed Wrn 2/3rds of CWA in slight risk of severe tstms. THURSDAY NIGHT...As front moves SEWD across CWA, chances for severe wx diminish. 40-60% NE-SE pop gradient. local severe tool reflects this with 6-20% NW-SE gradient 00z-06z and 0-12% chance 06z-12z. FRIDAY...20-30% NW-SE mainly morning pop gradient. Lingering convection across ern third of local area will exit east of I-75 after midday. Expect gusty offshore winds. && .LONG TERM... (Saturday through next Wednesday) Fair weather and a return to more seasonal temperatures are likely this weekend behind Friday`s cold front passage. Highs will be in the mid to upper 70s and lows in the 40s. With lower humidity, it will feel much more comfortable than the past several days. The large scale 500 mb pattern will transition to a fairly deep trough over the eastern CONUS early to mid week, though the GFS forecasts a deeper, less progressive trough than the ECMWF. The next chance for rain will be late Monday and early Tuesday as a cold front moves south through the region, though deep layer moisture and instability are not that impressive. The GFS is much cooler than the ECMWF behind this front, as it forecasts the 850 mb freezing line to reach south GA next Wednesday morning. If the GFS verifies, we would experience our first round of below-average temperatures in quite some time. && .AVIATION... Patchy fog and low clouds will dissipate this morning, with generally VFR conditions likely for the remainder of the day. The exception will be periods of MVFR-IFR vis/cigs and gusty winds in isolated to scattered thunderstorms, wich will be more numerous in the afternoon. Low clouds will likely develop overnight, with showers and thunderstorms developing near 12 UTC Thursday. && .MARINE... Winds and seas are expected to remain relatively low through today, except for a slight increase in the afternoon hours near the coast in association with the seabreeze. Onshore winds and seas will increase on Thursday as a front approaches from the west to borderline SCEC. Winds will turn offshore as the front passes on Friday and likely reach advisory levels Fri night into Sat before decreasing to below headline criteria and remaining offshore through the weekend. && .FIRE WEATHER... Humidity levels are expected to remain above critical values through Friday. Much drier air behind a cold front may allow red flag conditions to develop this weekend. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 86 66 84 63 82 / 20 20 70 50 20 Panama City 80 68 79 66 76 / 20 30 60 50 20 Dothan 87 66 84 59 79 / 30 40 70 40 20 Albany 87 65 83 60 78 / 40 30 70 50 20 Valdosta 86 64 84 62 80 / 40 20 70 60 30 Cross City 83 65 83 64 81 / 20 10 60 60 30 Apalachicola 80 67 79 68 76 / 10 20 60 50 20 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...None. GA...None. FL...None. GM...None. && $$ Block/Fournier
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1053 AM EDT WED APR 4 2012 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... A FRONTAL SYSTEM IS EXPECTED TO SETTLE SOUTH ACROSS THE AREA EARLY TODAY...EVENTUALLY PUSHING SOUTH OF THE OHIO RIVER. A WAVE OF LOW PRESSURE WILL MOVE THROUGH THE TENNESSEE VALLEY AROUND THURSDAY. IN THE WAKE OF THIS LOW...HIGH PRESSURE IS EXPECTED TO MOVE INTO THE AREA THROUGH THE END OF THE WEEK. ANOTHER FRONTAL SYSTEM MAY APPROACH THE AREA OVER THE WEEKEND...WITH HIGH PRESSURE MOVING BACK IN EARLY NEXT WEEK. && .NEAR TERM /REST OF TODAY/... SOME FRONTOGENESIS AND ISENTROPIC LIFT OVER THE AREA IS PRODUCING SCATTERED SHOWERS ACROSS SOUTHERN AND WESTERN PARTS OF THE AREA AT 1445Z. EXPECT THESE TO CONTINUE TO DEVELOP AND SPREAD EAST OVER THE NEXT COUPLE OF HOURS. IN ADDITION THESE SHOWERS COULD DEVELOP INTO THUNDERSTORMS OVER THE NEXT FEW HOURS AS INSTABILITY INCREASES SO KEPT A CHANCE FOR THUNDERSTORMS GOING LATE THIS MORNING AND INTO THE AFTERNOON APPROXIMATELY SOUTH OF I 70 WITH A SLIGHT CHANCE TO THE NORTH. THE HRRR MODEL IS SHOWING DEVELOPMENT ACROSS MUCH OF THE AREA THIS AFTERNOON AND EVENING BUT GIVEN IT/S OUTLIER STATUS AND ITS GENERALLY POORER PERFORMANCE LATELY GENERALLY THREW OUT IT/S MORE ROBUST SOLUTION. TWEAKED DEW POINTS/WINDS/TEMPERATURES/SKY COVER TO MATCH CURRENT CONDITIONS AND TRENDS BUT THIS RESULTED IN CHANGES OF ONLY A COUPLE DEGREES HERE AND THERE WITH SLIGHTLY HIGHER DEWPOINTS IN THE NORTH AS WELL AS SLIGHTLY WARMER TEMPERATURES IN THE SOUTH. STILL GOING WITH HIGHS IN THE MIDDLE 60S TO LOW 70S. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... OVERRUNNING IS EXPECTED TO DEVELOP NORTH OF THE FRONTAL BOUNDARY BY THIS EVENING AS AN UPPER LOW APPROACHES THE OHIO VALLEY FROM THE WEST. LEFT IN CHANCE POPS ACROSS THE SOUTH FOR TONIGHT. ONCE SURFACE WAVE PASSES THROUGH THE TENNESSEE VALLEY ON THURSDAY...HIGH PRESSURE WILL NOSE SOUTH FROM CANADA...RESULTING IN DRY CONDITIONS BY THURSDAY AND LASTING THE REST OF THE PERIOD. REALLY DID NOT STRAY FAR FROM PREVIOUS FORECAST TEMPERATURES THIS PERIOD. BASED ON PROGGED LOW LEVEL THICKNESSES...THE GFS MOS TEMPERATURE GUIDANCE LOOKS PRETTY REASONABLE. FREEZING TEMPERATURES ARE STILL POSSIBLE BY FRIDAY MORNING...HOWEVER WINDS AT THE SURFACE LOOK TO BE TOO STRONG FOR EVEN PATCHY FROST FORMATION...AND HAVE DECIDED TO CONTINUE TO OMIT THIS MENTION FROM THE FORECAST. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... LONG TERM PERIOD BEGINS WITH FAIRLY STRONG RIDGING AT THE SURFACE AND ALOFT OVER THE AREA. AN UPPER LEVEL WAVE AND TRAILING COLD FRONT MAKES PROGRESS INTO THE UPPER GREAT LAKES BY SATURDAY NIGHT INTO EARLY SUNDAY...WITH AN OPPORTUNITY FOR SHOWERS AND THUNDERSTORMS. A BRIEF QUIET WX PERIOD EXPECTED BEFORE ANOTHER UPPER WAVE CONSOLIDATES WITH THE INITIAL SYSTEM AND PARKS OVER THE NORTHEAST. THIS SYSTEM REPRESENTS THE ONLY SIGNIFICANT DISAGREEMENT BETWEEN THE MAJOR MODELS...IN THAT THE EURO IS MUCH MORE PROGRESSIVE WITH THE UPPER LOW. INITIALIZATION SEEMS TO BE INFLUENCED SLIGHTLY MORE BY THE PROGRESSIVE SOLUTION...AND THIS IS REASONABLE GIVEN THE ECMWF/S TYPICAL SUPERIORITY. THIS UPPER LOW SHOULD BRING AT LEAST 12-24 HOURS OPPORTUNITY FOR SHOWERS TO THE AREA. INITIALIZATIONS TEMPS APPEAR REASONABLE WITH MINOR TWEAKS. COOLING TREND SHOULD DOMINATE THE LONG TERM...WITH ABOVE NORMAL TEMPS EARLY TRANSITIONING TO BELOW NORMAL TEMPS WITH THE UPPER LOW. && .AVIATION /DISCUSSION FOR 15Z AMENDMENT/ LOOKS LIKE VFR CONDITIONS THRU THE DAY. WEAK AREA OF LOW PRESSURE IS OVER SWRN MO WITH A QUASI STATIONARY BOUNDARY ACROSS SRN INDIANA FROM NEAR KLWV - KCVG. LOW TO MID LEVEL CLOUDS ARE OVER IL JUST NORTH OF THE BOUNDARY WITH MID LEVEL DECK ACROSS IN AND OH. GUIDANCE SUGGESTS SOME LOW CLOUDS AROUND 5K FT AGL AROUND THIS AFTERNOON. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SMF NEAR TERM...CP SHORT TERM...SMF LONG TERM....NIELD AVIATION...MCCARTHY
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1133 AM EDT WED APR 4 2012 .UPDATE... ISSUED AT 1043 AM EDT WED APR 4 2012 CONVECTION THAT WAS ATTEMPTING TO MOVE INTO THE REGION FROM CENTRAL KY IN THE MORNING HAS DISSIPATED TO NOTHING MORE THAN SOME LOW TO MID LEVEL CLOUDINESS. THERE IS A RATHER LARGE SECTION OF THE AREA STARTING TO GET SOME SIGNIFICANT SUNSHINE. THE LINGERING VALLEY FOG AND STRATUS IN THE CUMBERLAND VALLEY HAS DISSIPATED. CONVECTIVE DEVELOPMENT TODAY WILL LIKELY HOLD OFF INTO THE EARLY TO MID AFTERNOON...OR GENERALLY LATER THAN THE 12Z NAM IS PROJECTING. THE APPROACHING BOUNDARY AS WELL AS MESOSCALE FEATURES SUCH AS DIFFERENTIAL HEATING FROM TERRAIN OR ALONG THE INTERFACES BETWEEN WHERE HEAVIER PRECIPITATION FELL ON TUE AFTERNOON/AND EVENING AND WHERE IT WAS MUCH LIGHTER OR NEARLY RAINFREEE AND ANY LEFTOVER OUTFLOWS ARE POSSIBLE POINTS WHERE DEVELOPMENT MIGHT OCCUR FIRST. THE MID LEVEL IMPULSE MOVING TOWARD THE MID ATLANTIC STATES MAY HAVE SOME FRINGE EFFECTS AS WELL THIS AFTERNOON INTO THIS EVENING IN AIDING IN SOME ORGANIZATION TO THE CONVECTION. SHEAR AND INSTABILITY PARAMETERS FORECAST BY THE MODELS APPEAR TO BE MORE OR LESS ON THE MARGINAL END OF THE SPECTRUM WITH THE FORECAST SOUNDINGS MORE MOIST WITH A BIT HIGHER PW COMPARED TO TUE. DEPENDING ON EVOLUTION OF INSTABILITY...A FEW STORM COULD PRODUCE DAMAGING WINDS AND OR MARGINALLY SEVERE HAIL AS NOTED IN THE MOST RECENT SPC OUTLOOK. HOWEVER...THE FLASH FLOOD THREAT MAY BE GREATER. THE ORIENTATION OF THE STALLED OR NEARLY STALLED OUT BOUNDARY SLOWLY SAGGING SOUTH OF THE OH RIVER AND WESTERLY FLOW...BUT PROJECTED STORM MOTION NEAR 15KT AND THE HIGH PW ON THE ORDER OF JUST UNDER 2SD ABOVE NORMAL DEFINITELY POINTS TO A THREAT FOR SOME HEAVY RAIN WHERE THUNDERSTORMS OCCUR...AS THERE COULD BE TRAINING. SOME LOCATIONS HAD SOME WATER ISSUES YESTERDAY...ESPECIALLY LETCHER COUNTY AND SOME LOCATIONS RECEIVED ABOUT 1 TO 2 INCHES OF RAIN FROM THUNDERSTORMS ON TUE AFTERNOON OR EVENING...WITH LOCALLY HIGHER AMOUNTS. GIVE ALL OF THESE FACTORS...WE WILL KEEP THE FLOOD WATCH IN EFFECT AS IS FOR THIS UPDATE. UPDATE ISSUED AT 745 AM EDT WED APR 4 2012 ISSUED A QUICK UPDATE TO ADJUST POPS IN THE NEAR TERM WITH THE LATEST EXPECTATIONS OF THIS FIRST WAVE THIS MORNING AND THEN BUILDING IT UP IN THE AFTERNOON A BIT FURTHER NORTH. IN ADDITION...UPDATED THE TEMPS...WINDS AND DEWPOINTS TO BETTER REFLECT CURRENT CONDITIONS AND TRENDS. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 340 AM EDT WED APR 4 2012 07Z SFC ANALYSIS SHOWS A LOW CENTERED OVER SOUTHERN MISSOURI WITH A WEST TO EAST WARM FRONT/ELONGATED AREA OF LOWER PRESSURE RUNNING GENERALLY ALONG THE OHIO RIVER. THIS BOUNDARY HAS REMAINED INTERMITTENTLY ACTIVE THROUGH THE NIGHT...EVEN AS THE MORE ROBUST... DIURNALLY DRIVEN...SLOW MOVING CONVECTION DIED OUT OVER EAST KENTUCKY DURING THE LATE EVENING. DO EXPECT THAT THIS REGION OF LOWER PRESSURE WILL BECOME MORE ACTIVE TOWARD DAWN IN CONJUNCTION WITH A SLOW MOVING BAND OF MID LEVEL SHORTWAVES RUNNING THROUGH THE SOUTHERN OHIO VALLEY. THE ENVIRONMENT IS RELATIVELY MOIST OVER THE AREA WITH DEWPOINTS RUNNING IN THE MID AND UPPER 50S WHILE TEMPERATURES ARE SETTLING INTO THE LOWER 60S IN MOST PLACES...EARLY THIS MORNING. THE MODELS ARE IN DECENT AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST AS THEY ALL ROLL A CLOSED AND SOMEWHAT CUT OFF LOW THROUGH THE SOUTHERN PLAINS AND TOWARDS THE LOWER OHIO VALLEY BY THURSDAY MORNING. FLAT RIDGING AND DEEP SOUTHWEST FLOW EXIST OUT AHEAD OF THIS LOW AFFECTING KENTUCKY AND THIS WILL BE SQUEEZED OFF TO THE EAST BY 12Z THURSDAY. AT THE SAME TIME...A DEEP TROUGH OVER THE NORTHEAST WILL SHIFT SLIGHTLY SOUTH. GIVEN THE MODEL SIMILARITIES ALOFT HAVE GONE WITH A BLENDED SOLUTION WITH A LEAN TOWARD THE HIGHER RESOLUTION NAM12...AND A NOD TO THE HRRR IN THE NEAR TERM... BUT TRANSLATED SLIGHTLY SOUTH IN LINE WITH THE OTHER MODELS LATTER IN THE SHORT TERM. AN ACTIVE WEATHER PERIOD IS UPON US WITH THE APPROACH OF THE UPPER LOW TO THE WEST AND THE STALLED BOUNDARY LAYING OVER NORTHERN PARTS OF EAST KENTUCKY. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP AND INCREASE THROUGH THE AREA LATER TODAY AS DIURNAL HEATING INITIATES CONVECTION...HELPED ALONG BY SFC CONVERGENCE WITH THE BOUNDARY AND SOME UPPER LEVEL DIVERGENCE. THE STEAMY BOUNDARY LAYER WILL CONTRIBUTE TO HIGH INSTABILITY TODAY WITH MID LEVEL WINDS FAVORABLE FOR MORE ORGANIZED CONVECTION. AS A RESULT...STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE THROUGH THE AREA WITH HIGH PW AIR SETTING THE STAGE FOR HEAVY RAIN FROM ANY HEALTHY STORMS. DAMAGING WINDS AND LARGE HAIL WILL BE THE MAIN THREAT FROM THESE. THE STORMS WILL BE MORE PROGRESSIVE THAN YESTERDAY...BUT TRAINING...AND PLENTY OF AREAS OF LOWER FFG AFTER YESTERDAY/S RAINS...WILL MAKE FLASH FLOODING A CONCERN LATER TODAY AND THROUGH THE FIRST PART OF THE NIGHT. ACCORDINGLY...WILL HOIST A FLASH FLOOD WATCH FOR ALL BUT OUR NORTHWEST COUNTIES. THE HEAVIER RAINS WILL DISSIPATE BY THURSDAY MORNING AS DRIER AIR SEEPS INTO THE REGION FROM THE NORTH...BUT THE THREAT OF SHOWERS AND THUNDERSTORMS WILL REMAIN THROUGH THE DAY. THE BAROCLINIC ZONE IN PLACE THROUGH THE AREA ON THURSDAY WILL KEEP THE NORTHERN COUNTIES UP TO 10 DEGREES COOLER THAN THE SOUTHERN ONES FOR HIGHS. HAVE FOLLOWED A BLEND OF THE MOS GUIDANCE THROUGH THE PERIOD ALLOWING THE MAV NUMBERS TO TEMPER THE MET/S...WITH LITTLE IN THE WAY OF TERRAIN ADJUSTMENTS GIVEN THE MOIST ENVIRONMENT. DID FAVOR THE MET POPS THROUGH THE SHORT TERM...BUT HAD THEM TRANSLATED MORE TO THE SOUTH OWING TO THE CONSENSUS FAVORING MORE SUPPRESSION OF THE FRONTAL BOUNDARY FROM THE HIGH TO THE NORTHEAST. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 305 AM EDT WED APR 4 2012 THE MODELS ARE IN GOOD AGREEMENT REGARDING THE EVOLUTION OF WEATHER SYSTEMS FOR THE DAY 4-7 PERIOD. INITIALLY...SCATTERED RAIN SHOWERS WILL BE PRESENT FROM THE TENNESSEE BORDER NORTHWARD TO THE HAL ROGERS PARKWAY AND ALONG AND NORTH OF THE HIGHWAY 80 CORRIDOR. THESE RAIN SHOWERS WILL LIKELY LINGER THROUGH 9 OR 10Z ACROSS THIS AREA ON FRIDAY MORNING...BEFORE EXITING INTO VIRGINIA BY 13Z OR SO. AFTER THAT...THE MODELS ALL AGREE THAT HIGH PRESSURE WILL BECOME FIRMLY ESTABLISHED ACROSS THE OHIO AND TENNESSEE VALLEY AREAS THROUGH SUNDAY MORNING. THE GFS AND ECMWF BOTH ARE QUICKLY MOVING A WEAK FRONTAL BOUNDARY AND UPPER LEVEL TROUGH ACROSS THE REGION ON SUNDAY. THESE FEATURES WILL JUST STRONG ENOUGH AND HAVE JUST ENOUGH MOISTURE ASSOCIATED WITH THEM TO SPARK ISOLATED TO SCATTERED RAIN SHOWERS. AT THIS TIME THE MODEL DATA INDICATE THAT THE ATMOSPHERE WILL ONLY BE ABLE TO SUPPORT ISOLATED THUNDERSTORM ACTIVITY. WITH ALL THAT IN MIND...THE INHERITED FORECAST FOR SUNDAY WAS ADJUSTED TO REFLECT PRECIPITATION CHANCE THAT WERE A GOOD DEAL LOWER...AND MORE IN LINE WITH THE LATEST MEXMOS DATA...WHICH WAS REFLECTIVE OF 20-30 PERCENT PRECIPITATION PROBABILITIES ACROSS THE BOARD. ANOTHER AREA OF WEAK HIGH PRESSURE WILL THEN BECOME ESTABLISHED ACROSS THE SUNDAY NIGHT AND MONDAY. ANOTHER EVEN MORE ILL DEFINED FRONTAL BOUNDARY AND UPPER TROUGH COMBO WILL BRING SCATTERED RAIN SHOWERS TO EASTERN KENTUCKY MONDAY NIGHT AND TUESDAY. THE WEATHER...SKY COVER...AND PRECIPITATION AMOUNT FORECASTS WERE ALL ADJUSTED BASED ON THE LOWER PRECIPITATION PROBABILITIES. ACCOUNTING FOR THE AMOUNT OF CLOUD COVER AND PRECIPITATION EXPECTED...AND WITH SOMEWHAT COOLER AIR MASSES EXPECTED TO MOVE ACROSS THE AREA...TEMPERATURES WILL BE VERY CLOSE TO NORMAL THROUGH MONDAY...AND MAY EVEN BE SEVERAL DEGREES BELOW NORMAL NEXT TUESDAY AS COOLER AIR MAKES A FAIRLY DEEP SOUTHWARD INTRUSION INTO THE EASTERN CONUS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 745 AM EDT WED APR 4 2012 WITH THE WARM FRONT LYING ACROSS THE AREA...CONVECTION IS POSSIBLE AT ALMOST ANYTIME AND ANYWHERE THROUGHOUT EAST KENTUCKY. DO EXPECT THE ACTIVITY TO BE AT A MINIMUM EARLY THIS MORNING FOR MOST PLACES... EXCEPT UP IN THE NORTH THANKS TO A PASSING SHORT WAVE. OTHERWISE... WILL LET THE DIURNAL CYCLE DRIVE THE DEVELOPMENT AND EXPANSION OF SHOWERS AND THUNDERSTORMS THROUGH THE AREA THIS AFTERNOON AND INTO THE EVENING. WITH THIS...HAVE ADDED VCTS INTO THE TAFS AFTER 14Z. STILL ANTICIPATE A LULL IN THE ACTIVITY UNTIL MIDDAY FOR MOST OF THE AREA AND THEN CONVECTION SHOULD BLOSSOM FROM LATE AFTERNOON AND LAST WELL INTO THE EVENING. ANY STORM WILL BRING WITH IT MVFR CIGS AND VIS DOWN TO IFR OR LESS IN HEAVY RAIN. STORMS AND MVFR CONDITIONS WILL BE POSSIBLE THROUGH 12Z THURSDAY. WINDS THROUGH THE PERIOD WILL BE GENERALLY FROM THE WEST AT 5 TO 10 KTS THROUGH THE PERIOD...THOUGH HIGHER IN AND AROUND ANY STORMS. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH THROUGH LATE TONIGHT FOR KYZ058>060-068-069- 079-080-083>088-104-106>120. && $$ UPDATE...JP SHORT TERM...GREIF LONG TERM....AR AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
745 AM EDT WED APR 4 2012 .UPDATE... ISSUED AT 745 AM EDT WED APR 4 2012 ISSUED A QUICK UPDATE TO ADJUST POPS IN THE NEAR TERM WITH THE LATEST EXPECTATIONS OF THIS FIRST WAVE THIS MORNING AND THEN BUILDING IT UP IN THE AFTERNOON A BIT FURTHER NORTH. IN ADDITION...UPDATED THE TEMPS...WINDS AND DEWPOINTS TO BETTER REFLECT CURRENT CONDITIONS AND TRENDS. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 340 AM EDT WED APR 4 2012 07Z SFC ANALYSIS SHOWS A LOW CENTERED OVER SOUTHERN MISSOURI WITH A WEST TO EAST WARM FRONT/ELONGATED AREA OF LOWER PRESSURE RUNNING GENERALLY ALONG THE OHIO RIVER. THIS BOUNDARY HAS REMAINED INTERMITTENTLY ACTIVE THROUGH THE NIGHT...EVEN AS THE MORE ROBUST... DIURNALLY DRIVEN...SLOW MOVING CONVECTION DIED OUT OVER EAST KENTUCKY DURING THE LATE EVENING. DO EXPECT THAT THIS REGION OF LOWER PRESSURE WILL BECOME MORE ACTIVE TOWARD DAWN IN CONJUNCTION WITH A SLOW MOVING BAND OF MID LEVEL SHORTWAVES RUNNING THROUGH THE SOUTHERN OHIO VALLEY. THE ENVIRONMENT IS RELATIVELY MOIST OVER THE AREA WITH DEWPOINTS RUNNING IN THE MID AND UPPER 50S WHILE TEMPERATURES ARE SETTLING INTO THE LOWER 60S IN MOST PLACES...EARLY THIS MORNING. THE MODELS ARE IN DECENT AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST AS THEY ALL ROLL A CLOSED AND SOMEWHAT CUT OFF LOW THROUGH THE SOUTHERN PLAINS AND TOWARDS THE LOWER OHIO VALLEY BY THURSDAY MORNING. FLAT RIDGING AND DEEP SOUTHWEST FLOW EXIST OUT AHEAD OF THIS LOW AFFECTING KENTUCKY AND THIS WILL BE SQUEEZED OFF TO THE EAST BY 12Z THURSDAY. AT THE SAME TIME...A DEEP TROUGH OVER THE NORTHEAST WILL SHIFT SLIGHTLY SOUTH. GIVEN THE MODEL SIMILARITIES ALOFT HAVE GONE WITH A BLENDED SOLUTION WITH A LEAN TOWARD THE HIGHER RESOLUTION NAM12...AND A NOD TO THE HRRR IN THE NEAR TERM... BUT TRANSLATED SLIGHTLY SOUTH IN LINE WITH THE OTHER MODELS LATTER IN THE SHORT TERM. AN ACTIVE WEATHER PERIOD IS UPON US WITH THE APPROACH OF THE UPPER LOW TO THE WEST AND THE STALLED BOUNDARY LAYING OVER NORTHERN PARTS OF EAST KENTUCKY. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP AND INCREASE THROUGH THE AREA LATER TODAY AS DIURNAL HEATING INITIATES CONVECTION...HELPED ALONG BY SFC CONVERGENCE WITH THE BOUNDARY AND SOME UPPER LEVEL DIVERGENCE. THE STEAMY BOUNDARY LAYER WILL CONTRIBUTE TO HIGH INSTABILITY TODAY WITH MID LEVEL WINDS FAVORABLE FOR MORE ORGANIZED CONVECTION. AS A RESULT...STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE THROUGH THE AREA WITH HIGH PW AIR SETTING THE STAGE FOR HEAVY RAIN FROM ANY HEALTHY STORMS. DAMAGING WINDS AND LARGE HAIL WILL BE THE MAIN THREAT FROM THESE. THE STORMS WILL BE MORE PROGRESSIVE THAN YESTERDAY...BUT TRAINING...AND PLENTY OF AREAS OF LOWER FFG AFTER YESTERDAY/S RAINS...WILL MAKE FLASH FLOODING A CONCERN LATER TODAY AND THROUGH THE FIRST PART OF THE NIGHT. ACCORDINGLY...WILL HOIST A FLASH FLOOD WATCH FOR ALL BUT OUR NORTHWEST COUNTIES. THE HEAVIER RAINS WILL DISSIPATE BY THURSDAY MORNING AS DRIER AIR SEEPS INTO THE REGION FROM THE NORTH...BUT THE THREAT OF SHOWERS AND THUNDERSTORMS WILL REMAIN THROUGH THE DAY. THE BAROCLINIC ZONE IN PLACE THROUGH THE AREA ON THURSDAY WILL KEEP THE NORTHERN COUNTIES UP TO 10 DEGREES COOLER THAN THE SOUTHERN ONES FOR HIGHS. HAVE FOLLOWED A BLEND OF THE MOS GUIDANCE THROUGH THE PERIOD ALLOWING THE MAV NUMBERS TO TEMPER THE MET/S...WITH LITTLE IN THE WAY OF TERRAIN ADJUSTMENTS GIVEN THE MOIST ENVIRONMENT. DID FAVOR THE MET POPS THROUGH THE SHORT TERM...BUT HAD THEM TRANSLATED MORE TO THE SOUTH OWING TO THE CONSENSUS FAVORING MORE SUPPRESSION OF THE FRONTAL BOUNDARY FROM THE HIGH TO THE NORTHEAST. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 305 AM EDT WED APR 4 2012 THE MODELS ARE IN GOOD AGREEMENT REGARDING THE EVOLUTION OF WEATHER SYSTEMS FOR THE DAY 4-7 PERIOD. INITIALLY...SCATTERED RAIN SHOWERS WILL BE PRESENT FROM THE TENNESSEE BORDER NORTHWARD TO THE HAL ROGERS PARKWAY AND ALONG AND NORTH OF THE HIGHWAY 80 CORRIDOR. THESE RAIN SHOWERS WILL LIKELY LINGER THROUGH 9 OR 10Z ACROSS THIS AREA ON FRIDAY MORNING...BEFORE EXITING INTO VIRGINIA BY 13Z OR SO. AFTER THAT...THE MODELS ALL AGREE THAT HIGH PRESSURE WILL BECOME FIRMLY ESTABLISHED ACROSS THE OHIO AND TENNESSEE VALLEY AREAS THROUGH SUNDAY MORNING. THE GFS AND ECMWF BOTH ARE QUICKLY MOVING A WEAK FRONTAL BOUNDARY AND UPPER LEVEL TROUGH ACROSS THE REGION ON SUNDAY. THESE FEATURES WILL JUST STRONG ENOUGH AND HAVE JUST ENOUGH MOISTURE ASSOCIATED WITH THEM TO SPARK ISOLATED TO SCATTERED RAIN SHOWERS. AT THIS TIME THE MODEL DATA INDICATE THAT THE ATMOSPHERE WILL ONLY BE ABLE TO SUPPORT ISOLATED THUNDERSTORM ACTIVITY. WITH ALL THAT IN MIND...THE INHERITED FORECAST FOR SUNDAY WAS ADJUSTED TO REFLECT PRECIPITATION CHANCE THAT WERE A GOOD DEAL LOWER...AND MORE IN LINE WITH THE LATEST MEXMOS DATA...WHICH WAS REFLECTIVE OF 20-30 PERCENT PRECIPITATION PROBABILITIES ACROSS THE BOARD. ANOTHER AREA OF WEAK HIGH PRESSURE WILL THEN BECOME ESTABLISHED ACROSS THE SUNDAY NIGHT AND MONDAY. ANOTHER EVEN MORE ILL DEFINED FRONTAL BOUNDARY AND UPPER TROUGH COMBO WILL BRING SCATTERED RAIN SHOWERS TO EASTERN KENTUCKY MONDAY NIGHT AND TUESDAY. THE WEATHER...SKY COVER...AND PRECIPITATION AMOUNT FORECASTS WERE ALL ADJUSTED BASED ON THE LOWER PRECIPITATION PROBABILITIES. ACCOUNTING FOR THE AMOUNT OF CLOUD COVER AND PRECIPITATION EXPECTED...AND WITH SOMEWHAT COOLER AIR MASSES EXPECTED TO MOVE ACROSS THE AREA...TEMPERATURES WILL BE VERY CLOSE TO NORMAL THROUGH MONDAY...AND MAY EVEN BE SEVERAL DEGREES BELOW NORMAL NEXT TUESDAY AS COOLER AIR MAKES A FAIRLY DEEP SOUTHWARD INTRUSION INTO THE EASTERN CONUS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 745 AM EDT WED APR 4 2012 WITH THE WARM FRONT LYING ACROSS THE AREA...CONVECTION IS POSSIBLE AT ALMOST ANYTIME AND ANYWHERE THROUGHOUT EAST KENTUCKY. DO EXPECT THE ACTIVITY TO BE AT A MINIMUM EARLY THIS MORNING FOR MOST PLACES... EXCEPT UP IN THE NORTH THANKS TO A PASSING SHORT WAVE. OTHERWISE... WILL LET THE DIURNAL CYCLE DRIVE THE DEVELOPMENT AND EXPANSION OF SHOWERS AND THUNDERSTORMS THROUGH THE AREA THIS AFTERNOON AND INTO THE EVENING. WITH THIS...HAVE ADDED VCTS INTO THE TAFS AFTER 14Z. STILL ANTICIPATE A LULL IN THE ACTIVITY UNTIL MIDDAY FOR MOST OF THE AREA AND THEN CONVECTION SHOULD BLOSSOM FROM LATE AFTERNOON AND LAST WELL INTO THE EVENING. ANY STORM WILL BRING WITH IT MVFR CIGS AND VIS DOWN TO IFR OR LESS IN HEAVY RAIN. STORMS AND MVFR CONDITIONS WILL BE POSSIBLE THROUGH 12Z THURSDAY. WINDS THROUGH THE PERIOD WILL BE GENERALLY FROM THE WEST AT 5 TO 10 KTS THROUGH THE PERIOD...THOUGH HIGHER IN AND AROUND ANY STORMS. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH FROM 11 AM EDT THIS MORNING THROUGH LATE TONIGHT FOR KYZ058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...GREIF SHORT TERM...GREIF LONG TERM....AR AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
959 AM MDT WED APR 4 2012 .UPDATE... CLOUD COVER AND THE LINGERING EASTERLY WINDS HAS KEPT MUCH OF THE AREA A BIT COOLER THAN FORECAST. SHORT RANGE MODELS SHOW THAT EVEN WITH THIS DELAY IN THE HEATING AND THE WARMING DOWNSLOPE WINDS THAT IT WILL COME BY THIS AFTERNOON AS THE SFC LOW MOVES INTO THE NORTH CENTRAL MONTANA PLAINS AND THE WARMING WESTERLY OR SOUTHWESTERLY WINDS WILL SET-UP AND THE CLOUDINESS WILL WANE ALLOWING FOR MORE INSOLATION/HEATING. HAVE ADJUSTED THE HOURLY TEMPS TO ACCOUNT FOR THE LOWER TEMPS THAN EXPECTED THIS LATE MORNING AND THE WARMING AS THE CLOUDS BREAK THIS AFTERNOON AND THE WINDS PICK UP. OTHER PORTIONS OF THE FORECAST STILL LOOK FINE WITH RESPECT TO FIRE WEATHER CONCERNS ACROSS SW MONTANA...AND PRECIP CHANCES DUE TO AN SCATTERED SHOWER OR ISOLATED THUNDERSTORMS ACROSS NORTH CENTRAL MONTANA. RUC SHOWING CAPES NEARING 250-350J/KG AND DECENT MID LVL LAPSE RATES AROUND 8.5 DEGREES C BY THIS AFTERNOON AND SHOULD ALLOW FOR THE FORECASTED AFTN ISOLATED T-STORMS. --SCHOTT && .AVIATION... UPDATED 1150Z. EXPECT VFR CONDITIONS EXCEPT OVER THE ROCKY MOUNTAIN FRONT WHERE MOUNTAINS WILL BECOME OBSCURED IN SNOW THIS AFTERNOON AND TONIGHT. A COLD FRONT IS EXPECTED TO REACH KCTB AND KHLN AROUND 20Z...KGTF AND KBZN 21Z-22Z AND KHVR AND KLWT AROUND 00Z. THE BEST BET FOR SHOWERS BEHIND THE COLD FRONT IS AT KCTB WITH SMALL THREATS AT KHLN/KGTF/KHVR. DO NOT EXPECT ANY SHOWERS AT KLWT AND KBZN. GUSTY SOUTHWEST WINDS ARE EXPECTED IMMEDIATELY BEHIND THE COLD FRONT BUT THEN ARE EXPECTED TO SHIFT TO THE WEST OR NORTHWEST THIS EVENING. DETAILS ON THE TIMING OF THE WIND SHIFT TO THE WEST OR NORTHWEST ARE UNCERTAIN. DO NOT HAVE A GOOD FEEL ON WHETHER THERE WILL BE ISOLATED THUNDERSTORMS THIS AFTERNOON. SOME GUIDANCE SUGGESTS THERE WILL BE NONE WHILE OTHER GUIDANCE SUGGESTS THERE WILL BE A SMALL THREAT. BLANK && .PREV DISCUSSION... /ISSUED 550 AM MDT WED APR 4 2012/ TODAY THROUGH FRIDAY...THE BEGINNING OF AN ACTIVE PERIOD OF WEATHER WILL START TODAY...AND THEN CONTINUE INTO FRIDAY. A PACIFIC COLD FRONT...CURRENTLY JUST MOVING INTO WESTERN MONTANA AT 4 AM...WILL MOVE SLOWLY EASTWARD TOWARDS CENTRAL MONTANA TODAY. EXPECT THIS FRONT TO MOVE EAST OF THE DIVIDE THIS AFTERNOON...AND THEN GRADUALLY MOVE THROUGH THE LEWISTOWN AREA THIS EVENING. MILD TEMPERATURES ARE EXPECTED AHEAD OF THE FRONT...WITH THE WARMEST LOCATIONS EXPECTED IN THE HAVRE/LEWISTOWN AREAS TODAY. AS THE FRONT MOVES EAST OF THE DIVIDE...EXPECT SCATTERED SHOWERS TO DEVELOP ALONG WITH A FEW THUNDERSTORMS. THE DYNAMICS ARE GOOD WITH THIS SYSTEM...BUT THE INSTABILITY IS LOW. SO FOR NOW...I REMOVED THE GUSTY WIND WORDING IN THE ZONES...BUT WE WILL CONTINUE TO WATCH THIS CLOSELY. AGAIN...COOLER AIR MOVES INTO THE REGION TONIGHT. AS THE MAIN STORM SYSTEM PULLS NORTHWARD INTO CANADA...A BAND OF PRECIPITATION IS EXPECTED TO DEVELOP OVER SOUTHWEST MONTANA. SOME SNOW IS LIKELY BY MORNING BETWEEN DILLON AND BIG SKY. FOR NOW...THE BEST ACCUMULATING SNOWFALL SHOULD BE ABOVE 7000 FEET...SO I WILL HOLD OFF ON AN ADVISORY FOR NOW. THE PRECIP WILL CONTINUE INTO THURSDAY OVER SOUTHWEST MONTANA...WITH JUST A FEW SHOWERS OVER CENTRAL MONTANA...WHILE THE HI-LINE AREA STAYS MOSTLY DRY ON THURSDAY AFTERNOON. AFTERNOON TEMPERATURES ON THURSDAY WILL BE CLOSE TO 20 DEGREES COOLER THAN WEDNESDAY. THEN FOR THURSDAY NIGHT AND INTO FRIDAY...BOTH THE EC/GFS MODEL PROG A STRONG AREA OF LOW PRESSURE TO DEVELOP OVER SOUTHERN WYOMING...AND THEN MOVE NORTHEASTWARD INTO THE UPPER MIDWEST. THIS TRACK WOULD ALLOW FOR HEAVY SNOW TO DEVELOP IN THE MOUNTAINS OF SOUTHWEST MONTANA ON THURSDAY NIGHT AND THEN SPREAD NORTHWARD INTO CENTRAL MONTANA BY FRIDAY MORNING. THE HEAVIEST SNOWFALL SHOULD OCCUR IN THE MOUNTAINS WITH THIS SYSTEM...BUT SEVERAL INCHES OF SNOW ARE POSSIBLE AT LOWER ELEVATIONS IN SOUTHWEST/CENTRAL MONTANA. THUS A WINTER STORM WATCH HAS BEEN ISSUED FOR ALL ELEVATIONS. AFTERNOON TEMPERATURES ON FRIDAY WILL CONTINUE THE COOLING TREND...WITH THE CLOUDS/PRECIP...MOST AREAS WILL ONLY SEE HIGHS IN THE 30S. BRUSDA FRIDAY NIGHT THROUGH WEDNESDAY...MODELS ARE IN FAIRLY GOOD AGREEMENT DURING THE PERIOD SO CONFIDENCE IN THE FORECAST IS ABOVE AVERAGE. FRIDAY NIGHT THE UPPER TROUGH OVER EASTERN MONTANA WILL MOVE SLOWLY EAST AND EXPECT SNOW TO DIMINISH. SATURDAY NORTHWEST FLOW IS EXPECTED ALONG WITH SOME RESIDUAL MOISTURE. DID NOT CHANGE THE INHERITED FORECAST WHICH HAD A SLIGHT CHANCE OF PRECIPITATION OVER THE PLAINS WITH A CHANCE OF SNOW OVER THE MOUNTAINS. THEREAFTER THE FORECAST AREA WILL BE UNDER THE INFLUENCE OF A STRONG UPPER RIDGE WHICH WILL MOVE OVER CENTRAL MONTANA MONDAY. THIS WILL RESULT IN A WARMING TREND WITH HIGHS REACHING THE MID 50S TO MID 60S ON MONDAY. MODELS DIFFER SOME ON HOW FAST THE UPPER RIDGE MOVES EAST THEREAFTER BUT IT LOOKS LIKE WARM TEMPERATURES WILL CONTINUE INTO MIDWEEK. AS FOR PRECIPITATION THE RIDGE SHOULD KEEP THE AREA DRY SATURDAY NIGHT THROUGH TUESDAY WITH THE POSSIBLE EXCEPTION OF THE MOUNTAINS OF THE ROCKY MOUNTAIN FRONT. MODELS ARE POINTING TO SOME INCREASE IN MOISTURE BY WEDNESDAY OR WEDNESDAY NIGHT SO WENT WITH A SLIGHT CHANCE OF SHOWERS FOR THE LOWER ELEVATIONS AND A CHANCE OF RAIN OR SNOW SHOWERS FOR THE MOUNTAINS BY LATE WEDNESDAY. BLANK && .PRELIMINARY POINT TEMPS/POPS... GTF 69 30 46 29 / 20 20 20 40 CTB 64 27 45 24 / 40 40 20 10 HLN 71 29 46 29 / 20 10 30 50 BZN 66 27 43 27 / 10 20 50 60 WEY 38 21 37 21 / 10 40 60 70 DLN 61 25 41 26 / 20 10 50 60 HVR 74 31 51 27 / 10 30 10 10 LWT 70 29 43 27 / 10 10 30 50 && .TFX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM THURSDAY EVENING THROUGH FRIDAY EVENING BEAVERHEAD...BROADWATER...CASCADE...FERGUS...GALLATIN... JEFFERSON...JUDITH BASIN...MADISON...MEAGHER. RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR ELEVATIONS BELOW 6000 FEET FOR GALLATIN...MADISON...MEAGHER. && $$ UPDATE...SCHOTT SHORT TERM...BRUSDA LONG TERM...BLANK AVIATION...BLANK WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
646 AM EDT WED APR 4 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN TODAY, BRINGING SUNNY SKIES LATER THIS MORNING AND BREEZY CONDITIONS. HIGH PRESSURE WILL KEEP QUIET WEATHER OVER THE AREA THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 645AM UPDATE...CURRENT FORECAST IS ON TRACK. CLOUD COVER IS BEGINNING TO BREAK UP AT A QUICKER PACE THIS MORNING AS THOUGHT. WINDS ARE SOMEWHAT LIGHTER THAN FORECAST, BUT STILL WITHIN REASON COMPARED TO THE FORECAST. NO REAL CHANGES OTHER THAN SOME TWEAKS TO THE ENHANCED SHORT TERM GRIDS. PREVIOUS DISCUSSION...IR IMAGERY AND GROUND OBS STILL SHOWING CLOUD COVER OVER MOST OF THE CWA, WITH SOME CLEARING FROM THE NW. THIS CLEARING WILL SLOWLY CONTINUE UNTIL AROUND DAY BREAK WHEN MIXING BEGINS TO CLEAR IT OUT SOMEWHAT FASTER. THIS WILL ALLOW FOR SUNNY SKIES LATER THIS MORNING AND THE REST OF THE DAY. AS HIGH PRESSURE BUILDS IN, THE PRESSURE GRADIENT WILL INCREASE OVER THE CWA, ALLOWING FOR WINDS TO INCREASE WITH GUSTS TO AROUND 20 MPH. RELATIVE HUMIDITY WILL BE FAIRLY DRY TODAY, DROPPING TO AROUND 30 PERCENT. MODELS HAVE MORE MOISTURE THAN THAT, BUT THINKING IS THEY ARE OVER DOING SFC MOISTURE, SO HAVE LOWERED DEW POINTS INTO THE UPPER 20S TO LOW 30S TODAY. THE HRRR SEEMS TO HAVE ONE OF THE BEST HANDLES ON THE RH TODAY. IT DOES SHOW INCREASING RH FROM THE NW THIS MORNING, ONLY TO FALL OFF LATE MORNING AND AFTERNOON AS MIXING OCCURS. EVEN WITH THE LOWERING RH, IT STILL SHOWS RH VALUES IN THE 40 PERCENT RANGE. SO, STARTING THERE AND TAKING ABOUT 10 PERCENT OFF OF THAT, STILL KEEPS FIRE WEATHER CONCERNS MARGINAL AT BEST. NOT TO MENTION, THE PRECIP CRITERIA HAS NOT BEEN MET FOR NY, AS MUCH OF THE CWA RECEIVED OVER A QUARTER INCH OF RAIN ON SUNDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH THE REMAINDER OF THE WEEK. THIS WILL KEEP THE WEATHER QUIET. LOOKING AT TEMPS TONIGHT, THEY WILL COOL TO THE LOWER 30S. THERE MAY BE SOME LOCALIZED AREAS OF BELOW FREEZING TEMPS, BUT NOT EXPECTED TO BE WIDESPREAD AT THIS TIME IN AREAS WHERE THE GROWING SEASON HAS STARTED. THUS, HAVE OPTED NOT TO ISSUE ANY PRODUCTS AT THIS TIME. && .LONG TERM /SATURDAY THROUGH TUESDAY/... .0345 AM UPDATE... VERY FEW CHANGES MADE TO THE LONG TERM AS PREVIOUS FORECAST HAD A GOOD HANDLE ON EXPECTED CONDITIONS. IN GENERAL...DRY/SEASONAL CONDITIONS EXPECTED TOWARDS THE START OF THE PERIOD WITH AN EVENTUAL SHIFT TOWARDS UNSETTLED CONDITIONS AND BELOW NORMAL TEMPS EARLY NEXT WEEK AS AN UPPER VORTEX BECOMES FIRMLY ESTABLISHED ACROSS EASTERN CANADA. BOTH GFS AND ECMWF SHOWING SURPRISING AGREEMENT WITH THE EVOLUTION OF THIS FEATURE...WITH BOTH AGREEING UPPER LOW WILL TAKE UP RESIDENCE ACROSS THE UPPER ST. LAWRENCE VALLEY BY MONDAY. UNFORTUNATELY...OUR REGION WILL BE EMBEDDED IN NORTHERLY FLOW TO THE SYSTEM/S WEST WHICH WILL SET UP A FAVORABLE CORRIDOR FOR THE PASSAGE OF UPPER SHORTWAVE DISTURBANCES ACROSS OUR REGION. BASED ON FAVORABLE MODEL AGREEMENT...HAVE LOWERED DAYTIME HIGHS A FEW DEGREES EACH DAY BEGINNING MON. .PREVIOUS LONG TERM DISCUSSION... THE LONG TERM STARTS OFF WITH HIGH PRESSURE IN CONTROL WITH FAIR AND MAINLY CLEAR WX FOR FRI AND SAT AND MOST OF SUNDAY. LATER ON SUNDAY...A WEAK FNTL SYSTEM MAY BRING AN INCREASE IN CLDS AND THE CHC FOR A FEW -SHRA ON SUN NGT. AFTER THIS TIME MDLS ARE IN PRETTY GOOD AGREEMENT THAT AN UPR TROF WILL BE AMPLIFYING OVER THE RGN WITH A TREND TWDS COOLER AND WETTER CONDITIONS TAKING HOLD. WE FOLLOWED HPC GDNC FOR THE MOST PART...BUT LOWERED MAXES A BIT FOR EARLY NXT WEEK GIVEN MDL TRENDS AND LATEST MOS GDNC. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS TO START OUT THE TAF PERIOD THIS MORNING AS LOW CLOUDS CONTINUE TO SLOWLY SLIDE SOUTH AND EAST OF THE REGION. BIG CONCERNS FOR TODAY WILL BE INCREASING WINDS BEHIND A WEAK COLD FRONT ALONG WITH INCREASING CLOUDS (POSSIBLE MVFR CIGS) THIS AFTERNOON. FOR NOW BEST POTENTIAL FOR MVFR CIGS WILL BE AT SYR/RME/ITH/BGM THIS AFTERNOON AFTER 18Z FOLLOWING FRONTAL PASSAGE. CONDITIONS MAY TEMPORARILY IMPROVE NEAR 00Z THIS EVENING...HOWEVER MODELS CONTINUE TO SUGGEST A RETURN OF MVFR CIGS AFTER 06Z AS LOW-LEVEL MOISTURE LINGERS AROUND. THE ONLY TWO LOCATIONS WHERE RESTRICTIONS ARE NOT EXPECTED AT THIS TIME INCLUDE BOTH AVP AND ELM AS BOTH SITES WILL REMAIN ALONG THE SOUTHERN EDGE OF THE DEVELOPING CLOUD SHIELD. THE OTHER STORY WILL BE INCREASING NORTHWESTERLY WINDS AFTER 14Z AS A STRONG PRESSURE GRADIENT REMAINS OVER THE AREA. EXPECT WIND GUSTS OF NEAR 25 KTS ACROSS THE FINGER LAKES AND TWIN TIERS...WITH GUSTS POSSIBLY APPROACHING 30 KTS AT BOTH SYR AND RME. WINDS WILL DECREASE THIS EVENING AS THE PRESSURE GRADIENT BEGINS TO WEAKEN WITH TIME. .OUTLOOK... THU THROUGH SUN...VFR. && .FIRE WEATHER... WHILE THERE IS A HIGH FIRE DANGER IN SOME AREAS, RED FLAG CRITERIA LOOKS TO NOT BE MET, OR FAIRLY MARGINAL IN SOME AREAS. FOR THE NEW YORK AREA, RAIN ON SUNDAY OF MORE THAN A QUARTER OF AN INCH OVER A LARGE AREA, HAS KEPT THE CRITERIA FROM BEING MET. ALSO, RELATIVE HUMIDITY WILL DROP TODAY. HOWEVER, IT DOES LOOK TO REMAIN IN THE LOW 30 PERCENT RANGE IN THE CATSKILL AREA. ALSO, WINDS ARE EXPECTED TO BE GUSTY TODAY, WITH SOME GUSTS APPROACHING 25 MPH, AGAIN, ESPECIALLY IN THE CATSKILL REGION. THIS, WHEN COMBINED WITH LOW FUEL MOISTURE, WOULD CAUSE BORDERLINE CONDITIONS, BUT NOT EXPECTING EXPLOSIVE FIRE GROWTH POTENTIAL AT THIS TIME. TEMPS WILL BE NEAR FREEZING OVER MUCH OF THE AREA TONIGHT. RH RECOVERY WILL BE MODERATE, WITH VALUES IN THE UPPER 60 TO MID 70 PERCENT RANGE. FOR TOMORROW, RH WILL NOT BE AS LOW AND WINDS WILL ARE NOT EXPECTED TO BE AS STRONG, THUS REDUCING THE THREAT OF REACHING CRITICAL FIRE WEATHER CONDITIONS. THIS WILL BE THE GENERAL RULE FOR THE REMAINDER OF THE WEEK AS HIGH PRESSURE BUILDS IN AND REMAINS IN CONTROL THROUGH THE WEEKEND. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI NEAR TERM...SLI SHORT TERM...SLI LONG TERM...CMG AVIATION...CMG FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
644 AM EDT WED APR 4 2012 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN TODAY, BRINGING SUNNY SKIES LATER THIS MORNING AND BREEZY CONDITIONS. HIGH PRESSURE WILL KEEP QUIET WEATHER OVER THE AREA THROUGH THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... IT IMAGERY AND GROUND OBS STILL SHOWING CLOUD COVER OVER MOST OF THE CWA, WITH SOME CLEARING FROM THE NW. THIS CLEARING WILL SLOWLY CONTINUE UNTIL AROUND DAY BREAK WHEN MIXING BEGINS TO CLEAR IT OUT SOMEWHAT FASTER. THIS WILL ALLOW FOR SUNNY SKIES LATER THIS MORNING AND THE REST OF THE DAY. AS HIGH PRESSURE BUILDS IN, THE PRESSURE GRADIENT WILL INCREASE OVER THE CWA, ALLOWING FOR WINDS TO INCREASE WITH GUSTS TO AROUND 20 MPH. RELATIVE HUMIDITY WILL BE FAIRLY DRY TODAY, DROPPING TO AROUND 30 PERCENT. MODELS HAVE MORE MOISTURE THAN THAT, BUT THINKING IS THEY ARE OVER DOING SFC MOISTURE, SO HAVE LOWERED DEW POINTS INTO THE UPPER 20S TO LOW 30S TODAY. THE HRRR SEEMS TO HAVE ONE OF THE BEST HANDLES ON THE RH TODAY. IT DOES SHOW INCREASING RH FROM THE NW THIS MORNING, ONLY TO FALL OFF LATE MORNING AND AFTERNOON AS MIXING OCCURS. EVEN WITH THE LOWERING RH, IT STILL SHOWS RH VALUES IN THE 40 PERCENT RANGE. SO, STARTING THERE AND TAKING ABOUT 10 PERCENT OFF OF THAT, STILL KEEPS FIRE WEATHER CONCERNS MARGINAL AT BEST. NOT TO MENTION, THE PRECIP CRITERIA HAS NOT BEEN MET FOR NY, AS MUCH OF THE CWA RECEIVED OVER A QUARTER INCH OF RAIN ON SUNDAY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH THE REMAINDER OF THE WEEK. THIS WILL KEEP THE WEATHER QUIET. LOOKING AT TEMPS TONIGHT, THEY WILL COOL TO THE LOWER 30S. THERE MAY BE SOME LOCALIZED AREAS OF BELOW FREEZING TEMPS, BUT NOT EXPECTED TO BE WIDESPREAD AT THIS TIME IN AREAS WHERE THE GROWING SEASON HAS STARTED. THUS, HAVE OPTED NOT TO ISSUE ANY PRODUCTS AT THIS TIME. && .LONG TERM /SATURDAY THROUGH TUESDAY/... .0345 AM UPDATE... VERY FEW CHANGES MADE TO THE LONG TERM AS PREVIOUS FORECAST HAD A GOOD HANDLE ON EXPECTED CONDITIONS. IN GENERAL...DRY/SEASONAL CONDITIONS EXPECTED TOWARDS THE START OF THE PERIOD WITH AN EVENTUAL SHIFT TOWARDS UNSETTLED CONDITIONS AND BELOW NORMAL TEMPS EARLY NEXT WEEK AS AN UPPER VORTEX BECOMES FIRMLY ESTABLISHED ACROSS EASTERN CANADA. BOTH GFS AND ECMWF SHOWING SURPRISING AGREEMENT WITH THE EVOLUTION OF THIS FEATURE...WITH BOTH AGREEING UPPER LOW WILL TAKE UP RESIDENCE ACROSS THE UPPER ST. LAWRENCE VALLEY BY MONDAY. UNFORTUNATELY...OUR REGION WILL BE EMBEDDED IN NORTHERLY FLOW TO THE SYSTEM/S WEST WHICH WILL SET UP A FAVORABLE CORRIDOR FOR THE PASSAGE OF UPPER SHORTWAVE DISTURBANCES ACROSS OUR REGION. BASED ON FAVORABLE MODEL AGREEMENT...HAVE LOWERED DAYTIME HIGHS A FEW DEGREES EACH DAY BEGINNING MON. .PREVIOUS LONG TERM DISCUSSION... THE LONG TERM STARTS OFF WITH HIGH PRESSURE IN CONTROL WITH FAIR AND MAINLY CLEAR WX FOR FRI AND SAT AND MOST OF SUNDAY. LATER ON SUNDAY...A WEAK FNTL SYSTEM MAY BRING AN INCREASE IN CLDS AND THE CHC FOR A FEW -SHRA ON SUN NGT. AFTER THIS TIME MDLS ARE IN PRETTY GOOD AGREEMENT THAT AN UPR TROF WILL BE AMPLIFYING OVER THE RGN WITH A TREND TWDS COOLER AND WETTER CONDITIONS TAKING HOLD. WE FOLLOWED HPC GDNC FOR THE MOST PART...BUT LOWERED MAXES A BIT FOR EARLY NXT WEEK GIVEN MDL TRENDS AND LATEST MOS GDNC. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS TO START OUT THE TAF PERIOD THIS MORNING AS LOW CLOUDS CONTINUE TO SLOWLY SLIDE SOUTH AND EAST OF THE REGION. BIG CONCERNS FOR TODAY WILL BE INCREASING WINDS BEHIND A WEAK COLD FRONT ALONG WITH INCREASING CLOUDS (POSSIBLE MVFR CIGS) THIS AFTERNOON. FOR NOW BEST POTENTIAL FOR MVFR CIGS WILL BE AT SYR/RME/ITH/BGM THIS AFTERNOON AFTER 18Z FOLLOWING FRONTAL PASSAGE. CONDITIONS MAY TEMPORARILY IMPROVE NEAR 00Z THIS EVENING...HOWEVER MODELS CONTINUE TO SUGGEST A RETURN OF MVFR CIGS AFTER 06Z AS LOW-LEVEL MOISTURE LINGERS AROUND. THE ONLY TWO LOCATIONS WHERE RESTRICTIONS ARE NOT EXPECTED AT THIS TIME INCLUDE BOTH AVP AND ELM AS BOTH SITES WILL REMAIN ALONG THE SOUTHERN EDGE OF THE DEVELOPING CLOUD SHIELD. THE OTHER STORY WILL BE INCREASING NORTHWESTERLY WINDS AFTER 14Z AS A STRONG PRESSURE GRADIENT REMAINS OVER THE AREA. EXPECT WIND GUSTS OF NEAR 25 KTS ACROSS THE FINGER LAKES AND TWIN TIERS...WITH GUSTS POSSIBLY APPROACHING 30 KTS AT BOTH SYR AND RME. WINDS WILL DECREASE THIS EVENING AS THE PRESSURE GRADIENT BEGINS TO WEAKEN WITH TIME. .OUTLOOK... THU THROUGH SUN...VFR. && .FIRE WEATHER... WHILE THERE IS A HIGH FIRE DANGER IN SOME AREAS, RED FLAG CRITERIA LOOKS TO NOT BE MET, OR FAIRLY MARGINAL IN SOME AREAS. FOR THE NEW YORK AREA, RAIN ON SUNDAY OF MORE THAN A QUARTER OF AN INCH OVER A LARGE AREA, HAS KEPT THE CRITERIA FROM BEING MET. ALSO, RELATIVE HUMIDITY WILL DROP TODAY. HOWEVER, IT DOES LOOK TO REMAIN IN THE LOW 30 PERCENT RANGE IN THE CATSKILL AREA. ALSO, WINDS ARE EXPECTED TO BE GUSTY TODAY, WITH SOME GUSTS APPROACHING 25 MPH, AGAIN, ESPECIALLY IN THE CATSKILL REGION. THIS, WHEN COMBINED WITH LOW FUEL MOISTURE, WOULD CAUSE BORDERLINE CONDITIONS, BUT NOT EXPECTING EXPLOSIVE FIRE GROWTH POTENTIAL AT THIS TIME. TEMPS WILL BE NEAR FREEZING OVER MUCH OF THE AREA TONIGHT. RH RECOVERY WILL BE MODERATE, WITH VALUES IN THE UPPER 60 TO MID 70 PERCENT RANGE. FOR TOMORROW, RH WILL NOT BE AS LOW AND WINDS WILL ARE NOT EXPECTED TO BE AS STRONG, THUS REDUCING THE THREAT OF REACHING CRITICAL FIRE WEATHER CONDITIONS. THIS WILL BE THE GENERAL RULE FOR THE REMAINDER OF THE WEEK AS HIGH PRESSURE BUILDS IN AND REMAINS IN CONTROL THROUGH THE WEEKEND. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI NEAR TERM...SLI SHORT TERM...SLI LONG TERM...CMG AVIATION...CMG FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EDT WED APR 4 2012 .SYNOPSIS... A STRONG BACK DOOR COLD FRONT WILL APPROACH FROM THE NORTH THIS EVENING...THEN SURGE SOUTH THROUGH THE AREA LATE TONIGHT AND THURSDAY MORNING. MUCH COOLER TEMPERATURES ARE EXPECTED IN THE WAKE OF THE FRONT THURSDAY AND FRIDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1000 AM WEDNESDAY... A MODEST MID-LEVEL SHORTWAVE MOVING THROUGH CENTRAL NORTH CAROLINA THIS MORNING HELPED TO INITIATE ISOLATED DEEP CONVECTION TOWARD KIXA AND KRWI AROUND SUNRISE...WITH JUST ENOUGH ELEVATED INSTABILITY AND STEEP LAPSE RATES NOTED AT LEAST ON FORECAST SOUNDINGS...SUCH AS THE KFAY NAM BUFR SOUNDING FOR 12Z TODAY...TO PROVIDE FOR ISOLATED SHOWERS AND THUNDERSTORMS. THE PRECIPITATION STARTED TO WANE DURING THE MID-MORNING HOURS...AND THIS PRECIPITATION AND ITS EVOLUTION WAS VERY WELL DEPICTED ON SOME OF THE 00Z WRF MODELS. WITH MSAS SHOWING A RELATIVE MINIMUM OF SURFACE-BASED LIFTED INDICES AND THETA-E OVER MUCH OF CENTRAL NORTH CAROLINA...AND IN SUBSIDENCE BEHIND THE MID-LEVEL WAVE AS FORECAST BY BOTH THE LATEST RUC AND NAM...THERE SHOULD BE LOW CHANCES FOR REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS UNTIL LATER IN THE AFTERNOON. AT THAT POINT...BUFR SOUNDINGS FROM THE NAM SHOW AVAILABLE INSTABILITY STARTING TO INCREASE...AS LOW-LEVEL CIN IS OVERCOME AND LAPSE RATES ACTUALLY STEEPEN...TO AT LEAST 7C/KM FROM 1000-500MB ON BOTH THE LATEST NAM AND RUC. WHILE JET SUPPORT STAYS WELL TO THE NORTH IN THE MID- AND UPPER-LEVELS... AND LOW-LEVEL WINDS ARE NOT FORECAST TO BE TOO STRONG...ONLY ABOUT 10-15 KNOTS FROM 925MB THROUGH 850MB WHICH IS COINCIDENT WITH SOME OF THE LIGHTER WINDS ALOFT ON THE LATEST LOCAL AMDAR SOUNDINGS... 850MB CONVERGENCE INCREASES AND INVERTED-V-TYPE BUFR SOUNDINGS TAKE SHAPE BY LATE IN THE AFTERNOON...CONTINUING INTO THE EVENING. WITH THE FRONT TO THE NORTH AND SURFACE TROUGHINESS DEVELOPING TO THE WEST DURING THE DAY...THE LIKELY SCENARIO IS THAT DEEPER CONVECTION WILL DEVELOP TO OUR NORTH AND WEST AND MOVE SOUTHEAST ACROSS THE AREA EITHER PROPAGATING OR REGENERATING OFF OF ITS COOL POOL. SOME OF THE WRF GUIDANCE SUGGESTS MUCH OF THE PRECIPITATION STAYING NEAR THE VIRGINIA BORDER AND NEAR OR WEST OF THE YADKIN RIVER THROUGH LATE AFTERNOON...WHILE OTHERS SHOW A SURGE IN SHOWERS AND STORMS MOVING SOUTHEAST ALONG AND SOUTH OF U.S. 64. WHILE LOCATION IS UNCERTAIN...A LIKELY SCENARIO IS SOME DEVELOPMENT OF A CLUSTER OF STORMS MOVING OVER SOME PART OF CENTRAL NORTH CAROLINA LATE TODAY AND THIS EVENING WITH A POTENTIAL FOR DAMAGING WINDS. WET-BULB ZERO VALUES ARE LOW...SO HAIL IS ALSO A THREAT. THE CURRENT HAZARDOUS WEATHER OUTLOOK DISCUSSES THE TIMING AND PRIMARY THREAT OF DAMAGING WINDS WELL. HIGH TEMPERATURES SHOULD REACH THE MID 80S OVER MUCH OF CENTRAL NORTH CAROLINA. THE AFTERNOON HIGH MAY COME CLOSE TO THE RECORD AT KRDU...WHERE IT IS A COOL 87 DEGREES RELATIVE TO SURROUNDING DAYS. THE KGSO RECORD IS 86...A LESSER CHANCE OF REACHING THAT ONE. THOUGH INSTABILITY WILL BEGIN TO WANE AFTER SUNSET...ADDITIONAL CONVECTION WILL BE POSSIBLE IN ASSOCIATION WITH THE BACK DOOR COLD FRONT PROGRESSING SOUTH THROUGH VIRGINIA INTO CENTRAL NORTH CAROLINA OVERNIGHT. WILL MAINTAIN A SLIGHT CHANCE (20%) NORTH TO LOW CHANCE (30%) SOUTH FOR THE LATE NIGHT HOURS...WITH ISOLATED THUNDERSTORMS MORE LIKELY IN SOUTHERN PORTIONS OF THE AREA. EXPECT LOWS TO RANGE FROM THE LOWER/MID 50S IN THE NORTH AND NORTHEAST TO THE UPPER 50S AND LOWER 60S IN THE SOUTH. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 310 AM WEDNESDAY... AN UPPER LOW CURRENTLY LIFTING OUT OF NORTHEAST NM WILL DRIFT EAST ACROSS THE MID MS RIVER VALLEY WEDNESDAY NIGHT... AND THEN BEGIN TO MOVE SOUTHEAST TOWARD AL/GA ON THURSDAY AS IT APPROACHES THE SOUTHERN EDGE OF BROAD CYCLONIC FLOW OVER THE NORTHEAST US. A COLD FRONT AND/OR REMNANT CONVECTIVE OUTFLOW SHOULD BE NEAR THE NC/SC BORDER BY 12Z THURSDAY...WHERE A FEW ISOLATED SHOWERS CANNOT BE RULED OUT DURING THE MORNING HOURS. HOWEVER...MOST OF THE CENTRAL NC SHOULD BE DRY THROUGH THURSDAY AFTERNOON AS A SURFACE HIGH PRESSURE RIDGE SETTLES IN BEHIND THE FRONT AND A WEAK SHORTWAVE UPPER RIDGE SHIFTS ACROSS NC AHEAD OF THE APPROACHING UPPER LOW. WHILE FORECAST SOUNDINGS SUGGEST THE BOUNDARY LAYER WILL BE SLOW TO SATURATE UNTIL LATER THURSDAY EVENING...THE LOW LEVEL COLD ADVECTION BEHIND THE FRONT SHOULD BE HELP TO LOCK IN STRATUS AT 2-3K FT WHERE MOISTURE WILL ALREADY EXIST. THUS...TEMPS WILL STRUGGLE TO RISE UNTO THE LOW TO MID 60S...A GOOD 20 DEGREES COOLER THAN WEDNESDAY. FORCING FOR ASCENT...IN THE FORM OF INCREASING DIVERGENCE ALOFT...WEAK LOW LEVEL WARM ADVECTION AND 60-80M HEIGHT FALLS...WILL ARRIVE THURSDAY EVENING AS THE UPPER LOW DIVES THROUGH AL/GA. WHILE THERE HAS BEEN GOOD MODEL CONSISTENCY IS THE GENERAL TRACK OF THE UPPER AND SURFACE LOWS...THERE ARE STILL 100-200 MILE DIFFERENCES THAT WILL IMPACT HOW FAR NORTH INTO NC BETTER RAIN COVERAGE WILL EXTEND. MOST OF THE SHOWERS WILL PASS TO OUR SOUTH THURSDAY NIGHT AS THE SURFACE LOW DEVELOPS AND MOVES TO NEAR SAVANNAH BY 06-12Z FRIDAY. HOWEVER...A SHORTWAVE DROPPING SOUTH OUT OF EASTERN CANADA INTO THE MID-ATLANTIC STATES SHOULD HELP DRAW MOISTURE NORTH INTO THE VICINITY OF THE 925-850MB FRONT WHICH IS FORECAST TO LIE ACROSS THE CAROLINAS. MODELS HAVE BEEN SHOWING AN AREA OF INCREASE LOW LEVEL FGEN DEVELOPING OVER NC LATER FRIDAY NIGHT...SO WHILE THE BEST SURFACE CONVERGENCE AND UPPER FORCING WILL BE JUST TO OUR SOUTH...WE SHOULD SEE PRECIP EXPAND AND INTENSIFY NORTHWARD ACROSS SOUTHERN AND EASTERN NC OVERNIGHT. WE DO NOT EXPECT ANY CONVECTION THURSDAY NIGHT AS LOW LEVELS WILL BE STABLE...MID LEVEL LAPSE RATES WILL BE WEAK... AND THE STRONGEST UPPER FORCING WILL BE TO OUR SOUTH. HOWEVER...IF THE SURFACE LOW TRACKS SLIGHTLY NORTH OF THE CURRENT FORECAST...THERE COULD BE ENOUGH INSTABILITY ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS TO SUPPORT A FEW ISOLATED THUNDERSTORMS. FORECAST POPS ARE ALREADY HIGH ACROSS THE SOUTH AFTER 21Z THURSDAY...EXPANDING NORTHWARD AFTER 03Z...WHICH SEEMS SUFFICIENT FOR THE CURRENT FORECAST PACKAGE. LOWS IN THE UPPER 40S. THE SURFACE LOW SHOULD BE OFF THE SC COAST BY 12Z FRIDAY..WITH PRECIP ENDING FROM WEST TO EAST DURING THE DAY. THE MSLP GRADIENT ON THE BACK SIDE OF THE SURFACE LOW WILL BE FAIRLY TIGHT...WITH MOST MODELS SHOWING A 15-20KT NORTHEASTERLY WIND OVER THE COASTAL PLAIN FRIDAY MORNING. THE DEPARTING LOW WILL ALSO DRAW DRIER AIR IN FROM THE NORTH AS WINDS BEGIN TO TURN TO NORTH-NORTHWESTERLY FRIDAY AFTERNOON. FORECAST SOUNDINGS NOW SHOW MOST OF THE CENTRAL BREAKING OUT FRIDAY...ALTHOUGH MODELS OFTEN HAVE A TENDENCY TO SCOUR LOW LEVEL MOISTURE TOO QUICKLY IN THE ABSENCE OF A FRONTAL SYSTEM. BECAUSE OF THIS...THE HIGH TEMP FORECAST FOR FRIDAY IS SOMEWHAT UNCERTAIN...BUT IT IS POSSIBLE THAT AREA SIN THE WEST COULD BREAK OUT AND BE AS WARM IF NOT WARMER THAN AREAS IN THE EAST. WILL FORECAST HIGHS GENERALLY AROUND 60. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 350 AM WEDNESDAY... HIGH PRESSURE OVER THE GREAT LAKES WILL BRIEFLY BUILD SOUTH ACROSS MUCH OF THE EASTERN US THIS WEEKEND...WHILE SEVERAL SHORTWAVES OVER EASTERN CANADA AND THE NORTHERN US WRAP UP OVER NEW ENGLAND AND LEAD TO A DEEP TROUGH ALONG THE EAST COAST NEXT WEEK. RAIN CHANCES APPEAR TO BE LOW BUT ALSO LESS PREDICTABLE DUE TO THE NORTHWESTERLY FLOW REGIME...ESPECIALLY FROM SUNDAY NIGHT ONWARD. HIGHS WARMING INTO THE LOW TO MID 70S BY SUNDAY WILL DROP BACK INTO THE 60S FOR THE FIRST HALF OF NEXT WEEK. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 1000 AM WEDNESDAY... 24-HR TAF PERIOD: EXPECT VFR CONDITIONS TO PREDOMINATE THROUGH 18Z THIS AFTERNOON IN ASSOC/W SUBSIDENCE IN THE WAKE OF AN UPPER LEVEL DISTURBANCE EXITING TO THE EAST. BY MID TO LATE AFTERNOON...EARLIER TOWARD THE TRIAD... EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO BE POSSIBLE AT TAF SITES IN ADVANCE OF A STRONG BACK DOOR COLD FRONT APPROACHING FROM THE NORTH...WITH SHOWERS/STORMS PERSISTING IN SOME AREAS THROUGH THE END OF THE TAF PERIOD. WINDS WILL BE WEST OR SW AT 5-10 KT THROUGH 00Z THIS EVENING...BECOMING NORTH AND EVENTUALLY NORTHEAST AT 10-15 KT BY OR SHORTLY AFTER 12Z THU MORNING. LOOKING AHEAD: BREEZY NORTHEAST WINDS (10-15 KT GUSTING TO 20 KT) CAN BE EXPECTED IN THE WAKE OF THE BACK DOOR COLD FRONTAL PASSAGE BETWEEN 09-18Z THURSDAY...ALONG WITH OVERCAST CEILINGS BETWEEN 3000-4500 FT AGL. AFTER 18Z THU...MVFR CONDITIONS AND LIGHT RAIN ARE EXPECTED IN ASSOC/W A DEVELOPING LOW PRESSURE SYSTEM OFF THE SOUTHEAST COAST. IFR CONDITIONS WILL BE POSSIBLE...PRIMARILY LATE THU EVENING INTO THU NIGHT. MVFR/IFR CEILINGS ARE EXPECTED TO LIFT AND SCATTER OUT BETWEEN 12-18Z FRIDAY IN ASSOC/W DRY AIR ADVECTING INTO THE AREA VIA BREEZY NNE FLOW. VFR CONDITIONS ARE EXPECTED TO PERSIST FROM EARLY FRIDAY AFTERNOON INTO THE WEEKEND. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...DJF/VINCENT SHORT TERM...SMITH LONG TERM...SMITH AVIATION...DJF/VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
642 AM EDT WED APR 4 2012 .SYNOPSIS... A STRONG BACK DOOR COLD FRONT WILL APPROACH FROM THE NORTH THIS EVENING AND SURGE SOUTHWARD THROUGH THE AREA LATE TONIGHT AND THURSDAY MORNING. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 315 AM WEDNESDAY... OVERVIEW: THE HEIGHT GRADIENT ALOFT WILL TIGHTEN OVER THE CAROLINAS AND MID-ATLANTIC TODAY IN ASSOC/W MODEST HEIGHT FALLS IN ADVANCE OF AN H5 TROUGH PROGRESSING SLOWLY S/SE FROM CANADA INTO THE LOWER GREAT LAKES AND NEW ENGLAND. ALTHOUGH DPVA WITH THE AFOREMENTIONED TROUGH WILL REMAIN WELL NORTH IN NEW ENGLAND...STRENGTHENING WESTERLY FLOW ALOFT WILL RESULT IN A POTENTIAL FOR DPVA IN THE FORM OF MINOR SHORTWAVES/MCVS ADVECTING INTO NC/VA FROM THE WEST THIS AFTERNOON INTO TONIGHT. IN ADDITION TO AN MCV NOTED OVER CENTRAL NC (VIA LATEST RUC DATA) AT 06Z...SEVERAL MCVS/DISTURBANCES WERE NOTED UPSTREAM OVER THE CENTRAL/LOWER MS RIVER VALLEY THIS MORNING. IN THE LOWER LEVELS...THE WARM FRONT PROGRESSING NORTH THROUGH SOUTHERN VA AS OF 06Z WILL STALL OUT IN NORTHERN VA TODAY...THEN RETREAT SOUTHWARD AS A BACK DOOR COLD FRONT THIS AFTERNOON AND EVENING...WITH A PRE-FRONTAL TROUGH PROGRESSING INTO CENTRAL NC BY 18-21Z. THE COLD FRONT WILL PROGRESS SOUTH THROUGH CENTRAL NC LATE TONIGHT/THU MORNING. PRECIPITATION CHANCES: THOUGH STEEP MID-LEVEL LAPSE RATES (7-8 C/KM) WERE PRESENT OVER NC/VA AND THE OH VALLEY AT 06Z THIS MORNING...MODEL GUIDANCE CONTINUES TO INDICATE LAPSE RATES WEAKENING TO 5.5-6 C/KM BETWEEN 18-00Z. HOWEVER...AN UNSEASONABLY WARM/MOIST AIRMASS WILL BE IN PLACE ACROSS CENTRAL NC TODAY...AND THIS SHOULD ALLOW FOR 500-1000 J/KG OF MLCAPE DURING PEAK HEATING...PERHAPS 1000-1500 J/KG IF MID-LEVEL LAPSE RATES REMAIN NEAR OR SLIGHTLY ABOVE 6 C/KM... PRIMARILY BETWEEN 18-21Z. GIVEN A LOW-LEVEL FOCUS (PRE-FRONTAL TROUGH) AND A POTENTIAL FOR DISTURBANCES ALOFT ADVECTING INTO THE AREA FROM THE WEST IN THE PRESENCE OF MARGINAL TO MODERATE INSTABILITY...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP BETWEEN 18-21Z THIS AFTERNOON. HOWEVER...UNCERTAINTY IN THE TIMING AND LOCATION OF CONVECTION PERSISTS...PRIMARILY IN ASSOCIATION WITH THE TRACK/EVOLUTION OF UPSTREAM DISTURBANCES ADVECTING TOWARD NC/VA VIA STRENGTHENING WESTERLY FLOW ALOFT. THE LATEST 00Z WRF-NMM INDICATES DRY CONDITIONS THROUGH 18Z...SHOWING ISOLD/SCT CONVECTION DEVELOPING OVER THE MOUNTAINS AND MOVING DOWNSTREAM INTO THE CENTRAL NC BY 21Z THIS AFTERNOON...WITH ADDITIONAL CONVECTION DEVELOPING IN VICINITY OF THE PRE-FRONTAL TROUGH OVER CENTRAL NC. THE 00Z WRF-ARW SHOWS SCATTERED CONVECTION DEVELOPING OVER CENTRAL NC PRIMARILY IN ASSOC/W THE PRE-FRONTAL TROUGH BETWEEN 18-21Z. AT THIS TIME WILL NOT CHANGE PRECIP CHANCES MUCH FROM THE PREVIOUS FORECAST...SHOWING A 40% CHANCE FOR SHOWERS/STORMS...WITH THE BEST CHANCE BETWEEN 19Z THIS AFTERNOON AND 01Z THIS EVENING. THOUGH INSTABILITY WILL BEGIN TO WANE AFTER SUNSET...ADDITIONAL CONVECTION WILL BE POSSIBLE IN ASSOC/W THE BACK DOOR COLD FRONT PROGRESSING SOUTH THROUGH VA INTO CENTRAL NC OVERNIGHT. HOWEVER...THIS MAY DEPEND ON HOW MUCH STABILIZATION OCCURS IN ASSOC/W CONVECTION DURING THE AFTERNOON AND EVENING. WILL MAINTAIN A SLIGHT CHANCE (20%) NORTH TO LOW CHANCE (30%) SOUTH OVERNIGHT...WITH ISOLD THUNDERSTORMS MORE LIKELY IN SOUTHERN PORTIONS OF THE AREA. TEMPERATURES: 1000-850 MB THICKNESSES ARE PROGGED AT 1390-1400 METERS THIS AFTERNOON. THESE THICKNESSES SUPPORT HIGHS IN THE LOWER/MID 80S... OR 82-85F. ALTHOUGH A FAIR AMOUNT OF MID/UPPER LEVEL CLOUD COVER IS PRESENT THIS MORNING...EXPECT A REASONABLE POTENTIAL FOR SOME CLEARING AND ENOUGH SUNSHINE FOR TEMPS TO REACH THE LOWER/MID 80S. LOWS TONIGHT WILL DEPEND ENTIRELY ON THE TIMING/PROGRESS OF THE BACK DOOR COLD FRONT SURGING SOUTH INTO THE AREA. AT THIS TIME...EXPECT LOWS TO RANGE FROM THE LOWER/MID 50S IN THE NORTH/NE TO THE UPPER 50S AND LOWER 60S IN THE SOUTH. SEVERE THREAT: THE SPC DAY 1 OUTLOOK INDICATES A SLIGHT RISK OF SEVERE STORMS TODAY OVER MOST OF CENTRAL NC. AS WESTERLY FLOW ALOFT STRENGTHENS...0-6 KM BULK SHEAR VALUES IN CENTRAL NC ARE EXPECTED TO INCREASE TO 25-35 KT THIS AFT/EVE...FURTHER INCREASING TO 30-40 KT AFTER 00Z. 0-6KM BULK SHEAR VALUES WILL CERTAINLY BE SUPPORTIVE OF MULTICELL ORGANIZATION...AND MAY BE AT THE LOW-END THRESHOLD FOR SUPERCELLULAR ORGANIZATION...PRIMARILY AFTER 00Z...OR IF THE HEIGHT GRADIENT ALOFT TIGHTENS/MID-LEVEL FLOW ACCELERATES IN ADVANCE OF AN UPPER LEVEL DISTURBANCE PROGRESSING INTO THE AREA THIS AFT/EVE (SHOULD THAT OCCUR). STEEP LOW-LEVEL LAPSE RATES ASSOC/W STRONG DIURNAL HEATING WILL CONTRIBUTE TO RELATIVELY HIGH DCAPE AND THE POTENTIAL FOR STRONG COLD POOLS THIS AFT/EVE. WITH THE ABOVE IN MIND...EXPECT THE BEST CHANCE FOR SEVERE WEATHER FROM 3-10 PM...WITH A PRIMARY THREAT OF DAMAGING WINDS OWING TO STEEP LOW-LEVEL LAPSE RATES AND RELATIVELY SPEEDY MID-LEVEL FLOW. SEVERE HAIL APPEARS LESS LIKELY GIVEN WEAK MID-LEVEL LAPSE RATES AND BULK SHEAR VALUES ON THE LOW-END OF/OR UNSUPPORTIVE OF ROTATING UPDRAFTS. GIVEN STRONG HEATING AND STEEP LOW-LEVEL LAPSE RATES...IF CONVECTION INITIATES ON THE HIGHER TERRAIN AND PROGRESSES EAST INTO THE WESTERN PIEDMONT DURING THE MID/LATE AFTERNOON...A LINE OF STORMS (ORGANIZING ALONG OUTFLOW) COULD DEVELOP AND POSE A THREAT FOR RELATIVELY WIDESPREAD DAMAGING WINDS. -VINCENT && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 310 AM WEDNESDAY... AN UPPER LOW CURRENTLY LIFTING OUT OF NORTHEAST NM WILL DRIFT EAST ACROSS THE MID MS RIVER VALLEY WEDNESDAY NIGHT... AND THEN BEGIN TO MOVE SOUTHEAST TOWARD AL/GA ON THURSDAY AS IT APPROACHES THE SOUTHERN EDGE OF BROAD CYCLONIC FLOW OVER THE NORTHEAST US. A COLD FRONT AND/OR REMNANT CONVECTIVE OUTFLOW SHOULD BE NEAR THE NC/SC BORDER BY 12Z THURSDAY...WHERE A FEW ISOLATED SHOWERS CANNOT BE RULED OUT DURING THE MORNING HOURS. HOWEVER...MOST OF THE CENTRAL NC SHOULD BE DRY THROUGH THURSDAY AFTERNOON AS A SURFACE HIGH PRESSURE RIDGE SETTLES IN BEHIND THE FRONT AND A WEAK SHORTWAVE UPPER RIDGE SHIFTS ACROSS NC AHEAD OF THE APPROACHING UPPER LOW. WHILE FORECAST SOUNDINGS SUGGEST THE BOUNDARY LAYER WILL BE SLOW TO SATURATE UNTIL LATER THURSDAY EVENING...THE LOW LEVEL COLD ADVECTION BEHIND THE FRONT SHOULD BE HELP TO LOCK IN STRATUS AT 2-3K FT WHERE MOISTURE WILL ALREADY EXIST. THUS...TEMPS WILL STRUGGLE TO RISE UNTO THE LOW TO MID 60S...A GOOD 20 DEGREES COOLER THAN WEDNESDAY. FORCING FOR ASCENT...IN THE FORM OF INCREASING DIVERGENCE ALOFT...WEAK LOW LEVEL WARM ADVECTION AND 60-80M HEIGHT FALLS...WILL ARRIVE THURSDAY EVENING AS THE UPPER LOW DIVES THROUGH AL/GA. WHILE THERE HAS BEEN GOOD MODEL CONSISTENCY IS THE GENERAL TRACK OF THE UPPER AND SURFACE LOWS...THERE ARE STILL 100-200 MILE DIFFERENCES THAT WILL IMPACT HOW FAR NORTH INTO NC BETTER RAIN COVERAGE WILL EXTEND. MOST OF THE SHOWERS WILL PASS TO OUR SOUTH THURSDAY NIGHT AS THE SURFACE LOW DEVELOPS AND MOVES TO NEAR SAVANNAH BY 06-12Z FRIDAY. HOWEVER...A SHORTWAVE DROPPING SOUTH OUT OF EASTERN CANADA INTO THE MID-ATLANTIC STATES SHOULD HELP DRAW MOISTURE NORTH INTO THE VICINITY OF THE 925-850MB FRONT WHICH IS FORECAST TO LIE ACROSS THE CAROLINAS. MODELS HAVE BEEN SHOWING AN AREA OF INCREASE LOW LEVEL FGEN DEVELOPING OVER NC LATER FRIDAY NIGHT...SO WHILE THE BEST SURFACE CONVERGENCE AND UPPER FORCING WILL BE JUST TO OUR SOUTH...WE SHOULD SEE PRECIP EXPAND AND INTENSIFY NORTHWARD ACROSS SOUTHERN AND EASTERN NC OVERNIGHT. WE DO NOT EXPECT ANY CONVECTION THURSDAY NIGHT AS LOW LEVELS WILL BE STABLE...MID LEVEL LAPSE RATES WILL BE WEAK... AND THE STRONGEST UPPER FORCING WILL BE TO OUR SOUTH. HOWEVER...IF THE SURFACE LOW TRACKS SLIGHTLY NORTH OF THE CURRENT FORECAST...THERE COULD BE ENOUGH INSTABILITY ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS TO SUPPORT A FEW ISOLATED THUNDERSTORMS. FORECAST POPS ARE ALREADY HIGH ACROSS THE SOUTH AFTER 21Z THURSDAY...EXPANDING NORTHWARD AFTER 03Z...WHICH SEEMS SUFFICIENT FOR THE CURRENT FORECAST PACKAGE. LOWS IN THE UPPER 40S. THE SURFACE LOW SHOULD BE OFF THE SC COAST BY 12Z FRIDAY..WITH PRECIP ENDING FROM WEST TO EAST DURING THE DAY. THE MSLP GRADIENT ON THE BACK SIDE OF THE SURFACE LOW WILL BE FAIRLY TIGHT...WITH MOST MODELS SHOWING A 15-20KT NORTHEASTERLY WIND OVER THE COASTAL PLAIN FRIDAY MORNING. THE DEPARTING LOW WILL ALSO DRAW DRIER AIR IN FROM THE NORTH AS WINDS BEGIN TO TURN TO NORTH-NORTHWESTERLY FRIDAY AFTERNOON. FORECAST SOUNDINGS NOW SHOW MOST OF THE CENTRAL BREAKING OUT FRIDAY...ALTHOUGH MODELS OFTEN HAVE A TENDENCY TO SCOUR LOW LEVEL MOISTURE TOO QUICKLY IN THE ABSENCE OF A FRONTAL SYSTEM. BECAUSE OF THIS...THE HIGH TEMP FORECAST FOR FRIDAY IS SOMEWHAT UNCERTAIN...BUT IT IS POSSIBLE THAT AREA SIN THE WEST COULD BREAK OUT AND BE AS WARM IF NOT WARMER THAN AREAS IN THE EAST. WILL FORECAST HIGHS GENERALLY AROUND 60. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 350 AM WEDNESDAY... HIGH PRESSURE OVER THE GREAT LAKES WILL BRIEFLY BUILD SOUTH ACROSS MUCH OF THE EASTERN US THIS WEEKEND...WHILE SEVERAL SHORTWAVES OVER EASTERN CANADA AND THE NORTHERN US WRAP UP OVER NEW ENGLAND AND LEAD TO A DEEP TROUGH ALONG THE EAST COAST NEXT WEEK. RAIN CHANCES APPEAR TO BE LOW BUT ALSO LESS PREDICTABLE DUE TO THE NORTHWESTERLY FLOW REGIME...ESPECIALLY FROM SUNDAY NIGHT ONWARD. HIGHS WARMING INTO THE LOW TO MID 70S BY SUNDAY WILL DROP BACK INTO THE 60S FOR THE FIRST HALF OF NEXT WEEK. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 640 AM WEDNESDAY... 24-HR TAF PERIOD: ASIDE FROM A BRIEF POTENTIAL FOR MVFR/IFR CEILINGS PRIOR TO ~13Z... EXPECT VFR CONDITIONS TO PREDOMINATE THROUGH 18Z THIS AFTERNOON IN ASSOC/W SUBSIDENCE IN THE WAKE OF AN UPPER LEVEL DISTURBANCE EXITING TO THE EAST. BY MID TO LATE AFTERNOON...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO BE POSSIBLE AT ALL TAF SITES IN ADVANCE OF A STRONG BACK DOOR COLD FRONT APPROACHING FROM THE NORTH...WITH SHOWERS/ STORMS PERSISTING IN SOME AREAS THROUGH THE END OF THE TAF PERIOD. WINDS WILL BE WEST OR SW AT 5-10 KT THROUGH 00Z THIS EVENING... BECOMING NORTH AND EVENTUALLY NORTHEAST AT 10-15 KT BY OR SHORTLY AFTER 12Z THU MORNING. LOOKING AHEAD: BREEZY NORTHEAST WINDS (10-15 KT GUSTING TO 20 KT) CAN BE EXPECTED IN THE WAKE OF THE BACK DOOR COLD FRONTAL PASSAGE BETWEEN 09-18Z THURSDAY...ALONG WITH OVERCAST CEILINGS BETWEEN 3000-4500 FT AGL. AFTER 18Z THU...MVFR CONDITIONS AND LIGHT RAIN ARE EXPECTED IN ASSOC/W A DEVELOPING LOW PRESSURE SYSTEM OFF THE SOUTHEAST COAST. IFR CONDITIONS WILL BE POSSIBLE...PRIMARILY LATE THU EVENING INTO THU NIGHT. MVFR/IFR CEILINGS ARE EXPECTED TO LIFT AND SCATTER OUT BETWEEN 12-18Z FRIDAY IN ASSOC/W DRY AIR ADVECTING INTO THE AREA VIA BREEZY NNE FLOW. VFR CONDITIONS ARE EXPECTED TO PERSIST FROM EARLY FRIDAY AFTERNOON INTO THE WEEKEND. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...SMITH LONG TERM...SMITH AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1251 PM CDT WED APR 4 2012 .AVIATION... THE UPPER LOW IS STILL OVER THE TEXAS PANHANDLE. THE SURFACE LOW IS OVER SOUTHERN MISSOURI WITH A COLD FRONT STRETCHING BACK TO THE SOUTHWEST. DRIER AIR IS STARTING TO MOVE INTO WESTERN ARKANSAS NOW. ONLY ISOLATED SHOWERS OR THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE FAR NORTH OR EAST. AREAS OF STRATOCUMULUS CONTINUE ACROSS ARKANSAS AND WILL KEEP SOME MVFR CONDITIONS GOING FOR THESE LOWER CLOUDS. OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH THE REST OF THE PERIOD. THE COLD FRONT WILL BE EAST OF THE MISSISSIPPI RIVER BY 12Z THURSDAY. && .PREV DISCUSSION... /ISSUED 637 AM CDT WED APR 4 2012/ AVIATION... CONDITIONS SHOULD REMAIN LARGELY VFR FOR ALL TAF SITES. THE EXCEPTION MAY BE KHOT AND KM89 FOR A BRIEF PERIOD THIS MORNING...AND ALSO ANY TAF SITES AFFECTED BY SHOWERS LATER THIS MORNING. DEWPOINT DEPRESSIONS ARE VERY SMALL AT THOSE SITES AND KHOT IS SHOWING FEW-SCT003 BASES. THEY ARE RIGHT ON THE CUSP OF DEVELOPING SOME FOG OR LOW CLOUDS SO HAVE THROWN A TEMPO FOR 4SM AND SCT003 AT THOSE TWO TERMINALS. OTHERWISE...HAVE TRENDED TOWARDS RUC GUIDANCE WHICH SHOWS SHOWERS DEVELOPING FROM ROUGHLY KFYV DOWN TO KELD BEFORE 14Z...THEN SHIFTING EAST OF ALL TERMINALS BY 18Z OR SO. NOT TERRIBLY CONFIDENT IN HOW MUCH REDEVELOPMENT OF SHOWER ACTIVITY WE ARE GOING TO SEE TODAY SO ONLY INCLUDED MENTION OF VCSH AT TERMINALS FOR A SHORT PERIOD THIS MORNING. WINDS WILL GRADUALLY TURN WSW THROUGH THE DAY AS THE FRONT PASSES THROUGH. LOOKS LIKE THERE SHOULD BE ENOUGH DRY AIR TO PRECLUDED FOG OR LOW CLOUDS TONIGHT. PREV DISCUSSION... /ISSUED 333 AM CDT WED APR 4 2012/ SHORT RANGE...TODAY THROUGH SATURDAY NIGHT MODELS REMAIN IN BASICALLY GOOD AGREEMENT THIS MORNING DEPICTING A SLOW MOVING UPPER LOW AND ASSOCIATED FRONTAL BOUNDARY MOVING ACROSS THE FORECAST AREA. GFS/ECMWF COMBO PREFERRED THIS MORNING WITH NAM SOLUTION INITIATING POORLY AND AS SUCH DISCOUNTED. CLOSED OFF UPPER LOW OVER THE TEXAS/OKLAHOMA PANHANDLES SHOWING UP CLEARLY ON MOISTURE CHANNEL IMAGERY THIS MORNING. SYSTEM REMAINS CUT OFF FROM THE PREVAILING FLOW AND WILL DRIFT SLOWLY EASTWARD ACROSS THE NORTHERN PART OF THE STATE OVER THE NEXT DAY OR SO...AND NOT EXPECTED TO CLEAR THE STATE UNTIL THURSDAY AFTERNOON. ASSOCIATED SURFACE BOUNDARY CURRENTLY OVER EASTERN OKLAHOMA AND ALSO EXPECTED TO TAKE ITS TIME GETTING THROUGH THE STATE...LIKELY NOT CLEARING THE MISSISSIPPI RIVER UNTIL LATE WEDNESDAY NIGHT/EARLY THURSDAY MORNING. UPPER IMPULSE MOVING THROUGH THE REGION THIS MORNING CONTINUES TO PRODUCE SCATTERED SHOWERS BUT OVERALL AREA CONTINUES TO DECREASE IN AREAL COVERAGE. STRONGEST CONVECTION REMAINS TO THE SOUTH OF THE FORECAST AREA BUT ISOLATED THUNDER CANNOT BE RULED OUT THIS MORNING ESPECIALLY ACROSS THE SOUTHERN COUNTIES. NEXT IMPULSE WILL MOVE THROUGH THE BASE OF THE UPPER LOW DURING THE AFTERNOON. JET DYNAMICS ASSOCIATED WITH THE WAVE WILL LIKELY LEAD TO ADDITIONAL CONVECTIVE DEVELOPMENT ALONG AND TO THE EAST OF THE AFOREMENTIONED SURFACE BOUNDARY WHICH SHOULD LIKELY BE OVER THE EASTERN THIRD OF THE FORECAST AREA. CAN NOT RULE OUT SOME STRONGER STORMS OVER THIS AREA. PRECIPITATION CHANCES WILL BE LESS FURTHER TO THE EAST AS DRIER AIR MOVES IN. UPPER LOW MOVES ACROSS THE NORTH TONIGHT AND THURSDAY WITH ANOTHER IMPULSE ROTATING THROUGH ITS BASE. THE RESULT WILL BE ANOTHER CHANCE OF SCATTERED SHOWERS AND A FEW THUNDERSTORMS WITH THE BEST CHANCES OVER THE NORTH CLOSER TO THE UPPER LOW. SYSTEM FINALLY CLEARS THE STATE BY THURSDAY EVENING WITH HIGH PRESSURE BUILDING IN BEHIND THE DEPARTING LOW WITH DRY CONDITIONS EXPECTED FRIDAY. NEXT COLD FRONT WILL APPROACH THE STATE DURING THE DAY SATURDAY. GFS KEEPS AREA DRY BUT ECMWF DOES PAINT A LITTLE QPF OVER THE NORTHWEST ZONES LATE IN THE DAY. OVERALL SPEED OF THE FRONT A LITTLE SLOWER AND WILL TRIM BACK POPS TO THE NORTHWEST SATURDAY AND AREA WIDE SATURDAY NIGHT AS BOUNDARY WILL BE BISECTING THE STATE FROM NORTHEAST TO SOUTHWEST BY THE END OF THE PERIOD. REGARDLESS...POPS WILL ONLY BE SLIGHT CHANCE TO LOW END CHANCE AS SYSTEM NOT VERY IMPRESSIVE. TEMPERATURES WILL BE TRICKY TODAY DEPENDING ON WHERE THE FRONT ENDS UP ALONG WITH PRECIP AND CLOUD COVER COMING INTO PLAY. WARMEST DAY STILL LOOKS TO BE TODAY WITH TEMPERATURES RETURNING TO NEAR NORMAL FOR THE REMAINDER OF THE PERIOD. MAV/MEX NUMBERS LOOK REASONABLE AND ARE GENERALLY ACCEPTED. LONG TERM...SUNDAY THROUGH TUESDAY... A COLD FRONT WILL SWEEP THROUGH THE STATE ON SUNDAY AS AN UPPER RIDGE BUILDS OVER THE HIGH PLAINS AND A TROUGH OVER THE EASTERN CONUS. REALLY DO NOT EXPECT MUCH IN THE WAY OF PRECIP AS RETURN FLOW WILL BE WEAK OR NON-EXISTENT IN THE DAYS LEADING UP TO SUN...AND UPPER SUPPORT SHOULD BE WELL REMOVED TO THE NORTH. THE COLD FRONT WILL STALL OUT TO THE SOUTH AND WEST OF THE STATE LATER IN THE PERIOD. PREVIOUS SHIFTS HAD SOME SLIGHT CHANCE POPS...MAINLY IN THE SOUTHWEST...ON MONDAY. WILL LEAVE THIS AS-IS DUE TO SHORTWAVE ENERGY ROTATING THROUGH EITHER NEAR ARKANSAS...OR OVERHEAD DEPENDING ON WHICH MODEL YOU BELIEVE. DID REMOVE PRECIP MENTION ON MONDAY NIGHT THOUGH AS LOSS OF DAYTIME HEATING AND WHAT MARGINAL UPPER SUPPORT WAS PRESENT SHOULD MEAN ANY SHOWER WOULD DIE A QUICK DEATH. AS FOR TEMPERATURES...THEY WILL BE MUCH CLOSER TO NORMAL VALUES VERSUS WHAT HAS BEEN SEEN LATELY. HIGHS FROM THE LOW 70S NORTH TO THE MID/UPPER 70S IN THE SOUTH WILL BE THE NORM. LOWS WILL BE IN THE LOW TO MID 50S INITIALLY...PERHAPS DIPPING INTO THE UPPER 30S TO LOW 40S IN THE NORTH BY MONDAY/TUESDAY NIGHTS. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 55 73 48 71 / 30 40 10 0 CAMDEN AR 54 78 53 73 / 20 20 10 0 HARRISON AR 52 72 46 70 / 30 40 10 0 HOT SPRINGS AR 54 75 53 72 / 20 30 10 0 LITTLE ROCK AR 55 76 53 72 / 30 30 10 0 MONTICELLO AR 56 79 54 73 / 30 20 10 0 MOUNT IDA AR 53 75 52 72 / 20 30 10 0 MOUNTAIN HOME AR 53 72 47 70 / 40 40 10 0 NEWPORT AR 55 74 49 71 / 30 40 10 0 PINE BLUFF AR 56 78 54 73 / 30 30 10 0 RUSSELLVILLE AR 53 74 50 71 / 30 30 10 0 SEARCY AR 55 75 50 71 / 30 30 10 0 STUTTGART AR 56 77 53 72 / 30 30 10 0 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AVIATION...51
AREA FORECAST DISCUSSION
NWS MELBOURNE
300 PM EDT WED APR 4 2012 .DISCUSSION... ...INCREASING CHANCE FOR STORMS LATE TOMORROW AND TOMORROW NIGHT... ...TURNING COOLER STARTING LATE FRIDAY... CURRENT-TONIGHT...SURFACE RIDGE AXIS LOCATED OVER THE NORTH BAHAMAS THE FLORIDA STRAITS AND INTO THE SOUTHEAST GULF OF MEXICO. LOW PRESSURE SYSTEM MOVING EAST ACROSS THE NORTH GULF OF MEXICO AND THE GULF COAST. LATEST RUC 500MB ANALYSIS PLACES STRONG NEGATIVE VORTICITY ADVECTION (NVA) AHEAD OF THE COMPLEX AND STRONGER POSITIVE VORTICITY ADVECTION (PVA) BEHIND THE SYSTEM. FLAT FLOW ALOFT WILL ALLOW THE UPPER LOW TO MOVE QUICKLY EAST AND OVER NORTHERN AREAS THIS EVENING. MORNING SOUNDINGS INDICATED COLD 500MB TEMPERATURES...-12C TO -14C RANGE...MOVING OVERHEAD THE SAME TIME THE VORTICITY MAXES CROSS OVERTOP NORTHERN COUNTIES. ALTHOUGH THE LATEST WEATHER ROUNDUP WAS INDICATING DEW POINTS MAINLY IN THE 50S IF ANY CELL DOES MANAGE TO DEVELOP ANY VERTICAL EXTENT IT WILL BE QUICKLY PUNCHING INTO EVEN DRIER AIR AND EVENTUALLY THE COLD TEMPERATURES ALOFT. IT COULD BE JUST A COUPLE OF STORMS THAT HAVE THE POTENTIAL TO BECOME STRONG ENOUGH TO PRODUCE STRONG DOWNBURSTS AND HAIL. ONCE THE SUN SETS AND THE ATMOSPHERE STABILIZES AND DECOUPLES LATE EVENING... WINDS SHOULD DROP OFF TO THE 5 TO 10 MPH RANGE. ANY FOG WILL BE SHALLOW AND MOSTLY LIKELY IN LOW SPOTS OR LOCALLY COOLER AND LESS WIND SITES SUCH AS AN AIRFIELD. LOWS IN THE 60S TO AROUND 70 FORT PIERCE SOUTH. THU-THU NIGHT...LOW PRESSURE SYSTEM MOVING EAST ACROSS THE SOUTHEAST STATES AND NORTHERN GULF OF MEXICO WILL CONTINUE TO KEEP THE SURFACE HIGH PRESSURE WELL SOUTH OF EAST CENTRAL FLORIDA. RESULTING SOUTH TO SOUTHWEST WINDFLOW WILL FEED MOISTURE FROM THE SOUTHEAST GULF AND FLORIDA STRAITS NORTHWARD OVER THE PENINSULA AND INCREASE THE DEPTH OF MOISTURE. COLD TEMPERATURES ALOFT...AGAIN IN THE -12C TO -14C RANGE...AND WEAK MID LEVEL DISTURBANCES CROSSING OVERHEAD LATE OVERNIGHT AND DURING THE MORNING MAY PROVIDE ENOUGH FORCING FOR ISOLATED SHOWERS IN THE MORNING AND SCATTERED AFTERNOON STORMS IN THE NORTH HALF OF THE FORECAST AREA AND ISOLATED OVER THE SOUTHERN HALF. HIGHS IN THE UPPER 80S EXCEPT WESTERN PORTIONS OF OSCEOLA AND OKEECHOBEE ALONG THE KISSIMMEE RIVER FROM LAKE KISSIMMEE SOUTH. STORM CHANCES CONTINUE TO INCREASE FROM N-S FROM AROUND SUNSET INTO THE MID-LATE EVENING AS HIGHER BAND OF PWATS OVERSPREAD MOST OF THE CWA AHEAD OF THE LATER-ARRIVING MID LEVEL SHORT WAVE TROUGH AND FRONTAL BOUNDARY. INTERESTING TO SEE THAT THE LATE AFTERNOON SPC DAY 2 OUTLOOK PLACED THE NRN 2/3 CWA IN "SLGT RISK". POTENTIAL LOOKS LIKE IT SHOULD BE CENTERED AROUND 00Z...2-3 HRS EITHER SIDE. CLOUD COVER FROM UPSTREAM BLOWOFF AND/OR LOSS OF DAYTIME HEATING COULD BE A LIMITING FACTOR IN STORM STRENGTH...REMAINS TO BE SEEN. FRI-SAT...SHORTWAVE TROUGH AXIS WILL PUSH OFF THE COAST ON FRI AND AN EARLY APRIL COLD FRONT WILL SLIDE INTO THE AREA LATE. WILL HOLD ONTO A CHANCE OF STORMS FRI AHEAD OF THE FRONT AS MAX TEMPS WILL CONTINUE WARM IN THE MID-UPPER 80S. MOS POPS REALLY DROP OFF FRI NIGHT AS GUSTY NORTH/NORTHEAST WINDS BRING IN MUCH DRIER AIR. WILL NOT CARRY ANY POPS OVER LAND BUT WOULD NOT BE SURPRISED TO SEE A FEW LIGHT SHOWERS ESPECIALLY ALONG THE TREASURE COAST FRI NIGHT INTO SAT MORNING. THE LATEST MOS INDICATES MAX TEMPERATURES BELOW NORMAL FOR SAT WITH READINGS MAINLY IN THE 70S. SUN-WED (PREV)...SURFACE HIGH PRESSURE RIDGE AXIS WILL SLIDE INTO THE AREA SUN WHILE WEAKENING. THE RIDGE WILL WEAKEN FURTHER MON AS IT SHIFTS INTO SOUTH FLORIDA. NEAR TO SLIGHTLY BELOW NORMAL TEMPS ARE INDICATED SUN/MON. THE GFS INDICATES A FRONTAL BOUNDARY DROPPING DOWN FROM THE NORTH AGAIN ON TUE WITH SLIGHT CHANCE POPS. SINCE DEW POINTS ARE ONLY FORECAST TO BE IN THE 50S AND FRONTAL CONVERGENCE LOOKS WEAK...WILL NOT INTRODUCE POPS YET. COOLER THAN NORMAL TEMPS ARE INDICATED BEHIND THE FRONT ON WED AS AMPLIFYING FLOW ALOFT DRIVES SINGLE DIGIT 850 MB TEMPS INTO THE AREA AGAIN. && .AVIATION...ISOLATED MVFR TIL 02Z FROM AROUND LAKE GEORGE TO DAYTONA BEACH THEN SOUTH ALONG THE COAST TO JUPITER INLET AND INDIANTOWN. AFTER 02Z VFR WITH TEMPO MVFR MIST 09Z-12Z. && .MARINE...CURRENT-THIS EVENING...THE TWO NOAA BUOYS WERE RECORDING SPREAD OF SOUTHWEST WIND...AROUND 5 KNOTS AT BUOY 009 AND AROUND 15 KNOTS AT BUOY 010 AND SEAS RANGING FROM 3 TO 5 5 FEET WITH A 2 TO 3 FOOT LONG PERIOD SWELL. THE TWO SCRIPPS BUOYS...4 AND 6 NM OFF THE BEACH... WERE RECORDING 2 FOOT LONG PERIOD SEAS. WINDS SHOULD TAKE ON A SOUTHERLY COMPONENT NEAR THE COAST FROM AROUND FORT PIERCE INLET SOUTH AS A SEA BREEZE CIRCULATION STRUGGLES TO SET UP BUT DOES NOT SHIFT PAST SOUTH SOUTHEAST AND ONLY UNTIL MID EVENING IF THAT. OVERNIGHT AND THU...AFTER MID EVENING IT SHOULD BE SOUTHWESTERLY WINDS 10 TO 15 KNOTS OVERNIGHT AND THURSDAY WITH THE SURFACE RIDGE AXIS REMAINING WELL SOUTH OF THE MARINE FORECAST AREA. WINDS WILL INCREASE LATE THU AS THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE TO THE SOUTH AND THE ADVANCING FRONT STRENGTHENS. CHANCE FOR STORMS INCREASES FROM LATE AFTERNOON/EVENING AND CONTINUES N-S INTO FRI. THE MODELS SHOW INCREASING NORTH WINDS LATE FRI AS A COLD FRONT DROPS DOWN THE PENINSULA...WITH SMALL CRAFT ADVISORY CONDITIONS LOOKING TO BE A GOOD BET BY FRI EVENING. THIS WEEKEND...BREEZY NORTHEAST WINDS ARE EXPECTED SAT WITH ADVISORY CONDITIONS CONTINUING. HIGH PRESSURE WILL WEAKEN SUNDAY WITH RIDGE AXIS SETTLING CLOSER TO THE WATERS SO WINDS WILL DIMINISH...BUT SEAS WILL BE SLOW TO SUBSIDE. && .FIRE WEATHER...ALTHOUGH TEMPERATURES WILL BE WARMER THU THE DEEPENING SOUTH TO SOUTHWEST WIND SHOULD TRANSPORT HIGHER DEW POINT AIR INTO EAST CENTRAL AND KEEP RELATIVE HUMIDITY VALUES ABOVE CRITICAL THRESHOLDS. TRANSPORT WINDS HOVER AROUND 15 MPH. SLIGHT DRYING SHOULD OCCUR ON FRI AS A FRONT DROPS DOWN FROM THE NORTH BUT NO LOW RH IS FORECAST. NORTH WINDS COULD BECOME GUSTY LATE IN THE AFTERNOON ESPECIALLY ALONG THE NORTH COAST. THIS WEEKEND...WINDS WILL VEER QUICKLY TO THE NORTHEAST ON SAT. IT SHOULD BE BREEZY ALONG THE COAST. MIN RH VALUES 35-40 PERCENT ARE EXPECTED ACROSS THE NORTH INTERIOR. ONSHORE FLOW WILL DIMINISH SUN AND MIN RH VALUES AROUND 35 PERCENT SHOULD OCCUR ACROSS THE NORTH INTERIOR. && .PRELIMINARY POINT TEMPS/POPS... DAB 68 89 67 84 / 20 30 40 50 MCO 67 89 68 86 / 10 30 40 40 MLB 69 87 70 86 / 20 20 40 40 VRB 69 88 70 86 / 20 20 40 40 LEE 66 89 67 85 / 10 40 40 40 SFB 66 89 68 86 / 10 30 40 40 ORL 67 89 69 86 / 10 30 40 40 FPR 70 88 70 86 / 20 20 40 40 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...WIMMER LONG TERM/IMPACT WX....CRISTALDI
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1224 PM EDT WED APR 4 2012 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW && .SYNOPSIS... A FRONTAL SYSTEM IS EXPECTED TO SETTLE SOUTH ACROSS THE AREA EARLY TODAY...EVENTUALLY PUSHING SOUTH OF THE OHIO RIVER. A WAVE OF LOW PRESSURE WILL MOVE THROUGH THE TENNESSEE VALLEY AROUND THURSDAY. IN THE WAKE OF THIS LOW...HIGH PRESSURE IS EXPECTED TO MOVE INTO THE AREA THROUGH THE END OF THE WEEK. ANOTHER FRONTAL SYSTEM MAY APPROACH THE AREA OVER THE WEEKEND...WITH HIGH PRESSURE MOVING BACK IN EARLY NEXT WEEK. && .NEAR TERM /REST OF TODAY/... SOME FRONTOGENESIS AND ISENTROPIC LIFT OVER THE AREA IS PRODUCING SCATTERED SHOWERS ACROSS SOUTHERN AND WESTERN PARTS OF THE AREA AT 1445Z. EXPECT THESE TO CONTINUE TO DEVELOP AND SPREAD EAST OVER THE NEXT COUPLE OF HOURS. IN ADDITION THESE SHOWERS COULD DEVELOP INTO THUNDERSTORMS OVER THE NEXT FEW HOURS AS INSTABILITY INCREASES SO KEPT A CHANCE FOR THUNDERSTORMS GOING LATE THIS MORNING AND INTO THE AFTERNOON APPROXIMATELY SOUTH OF I 70 WITH A SLIGHT CHANCE TO THE NORTH. THE HRRR MODEL IS SHOWING DEVELOPMENT ACROSS MUCH OF THE AREA THIS AFTERNOON AND EVENING BUT GIVEN IT/S OUTLIER STATUS AND ITS GENERALLY POORER PERFORMANCE LATELY GENERALLY THREW OUT IT/S MORE ROBUST SOLUTION. TWEAKED DEW POINTS/WINDS/TEMPERATURES/SKY COVER TO MATCH CURRENT CONDITIONS AND TRENDS BUT THIS RESULTED IN CHANGES OF ONLY A COUPLE DEGREES HERE AND THERE WITH SLIGHTLY HIGHER DEWPOINTS IN THE NORTH AS WELL AS SLIGHTLY WARMER TEMPERATURES IN THE SOUTH. STILL GOING WITH HIGHS IN THE MIDDLE 60S TO LOW 70S. && .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/... OVERRUNNING IS EXPECTED TO DEVELOP NORTH OF THE FRONTAL BOUNDARY BY THIS EVENING AS AN UPPER LOW APPROACHES THE OHIO VALLEY FROM THE WEST. LEFT IN CHANCE POPS ACROSS THE SOUTH FOR TONIGHT. ONCE SURFACE WAVE PASSES THROUGH THE TENNESSEE VALLEY ON THURSDAY...HIGH PRESSURE WILL NOSE SOUTH FROM CANADA...RESULTING IN DRY CONDITIONS BY THURSDAY AND LASTING THE REST OF THE PERIOD. REALLY DID NOT STRAY FAR FROM PREVIOUS FORECAST TEMPERATURES THIS PERIOD. BASED ON PROGGED LOW LEVEL THICKNESSES...THE GFS MOS TEMPERATURE GUIDANCE LOOKS PRETTY REASONABLE. FREEZING TEMPERATURES ARE STILL POSSIBLE BY FRIDAY MORNING...HOWEVER WINDS AT THE SURFACE LOOK TO BE TOO STRONG FOR EVEN PATCHY FROST FORMATION...AND HAVE DECIDED TO CONTINUE TO OMIT THIS MENTION FROM THE FORECAST. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... LONG TERM PERIOD BEGINS WITH FAIRLY STRONG RIDGING AT THE SURFACE AND ALOFT OVER THE AREA. AN UPPER LEVEL WAVE AND TRAILING COLD FRONT MAKES PROGRESS INTO THE UPPER GREAT LAKES BY SATURDAY NIGHT INTO EARLY SUNDAY...WITH AN OPPORTUNITY FOR SHOWERS AND THUNDERSTORMS. A BRIEF QUIET WX PERIOD EXPECTED BEFORE ANOTHER UPPER WAVE CONSOLIDATES WITH THE INITIAL SYSTEM AND PARKS OVER THE NORTHEAST. THIS SYSTEM REPRESENTS THE ONLY SIGNIFICANT DISAGREEMENT BETWEEN THE MAJOR MODELS...IN THAT THE EURO IS MUCH MORE PROGRESSIVE WITH THE UPPER LOW. INITIALIZATION SEEMS TO BE INFLUENCED SLIGHTLY MORE BY THE PROGRESSIVE SOLUTION...AND THIS IS REASONABLE GIVEN THE ECMWF/S TYPICAL SUPERIORITY. THIS UPPER LOW SHOULD BRING AT LEAST 12-24 HOURS OPPORTUNITY FOR SHOWERS TO THE AREA. INITIALIZATIONS TEMPS APPEAR REASONABLE WITH MINOR TWEAKS. COOLING TREND SHOULD DOMINATE THE LONG TERM...WITH ABOVE NORMAL TEMPS EARLY TRANSITIONING TO BELOW NORMAL TEMPS WITH THE UPPER LOW. && .AVIATION /DISCUSSION FOR 1800Z ISSUANCE/... RADAR INDICATES LIGHT SHOWERS ACROSS CENTRAL IL EWD INTO CENTRAL INDIANA AND DWON THRU SRN PARTS OF INDIANA. QUASI STATIONARY FRONTAL BOUNDARY IS ACROSS SRN INDIANA WHERE THERE IS SLY FLOW SOUTH OF THE BOUNDARY THAT IS TRACKING NWD OVER THE FRONT PRODUCING THE SHOWER ACTIVITY. MAY HAVE TO REFLECT IN THE TAFS THAT THIS ACTIVITY IS MORE WIDESPREAD RESULTING IN OCCASSIONAL MVFR CONDITIONS AND THAT THERE IS ALSO SOME ISOLATED THUNDER NOW SW OF KIND. LOOKS LIKE PRECIPITATION WILL LINGER THRU EARLY THIS EVENING BEFORE HIGH PRESSURE FROM THE NORTH BUILDS SOUTHWARD FORCING THE FRONT AND SHOWERS AWAY FROM AREA. LOOK FOR VFR CONDITIONS OVERNIGHT FOR MOST STATIONS TONIGHT THRU THURSDAY MORNING. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SMF NEAR TERM...CP SHORT TERM...SMF LONG TERM....NIELD AVIATION...MCCARTHY
AREA FORECAST DISCUSSION
NWS JACKSON KY
216 PM EDT WED APR 4 2012 .UPDATE... ISSUED AT 213 PM EDT WED APR 4 2012 CU HAS DEVELOPED IN MANY AREAS RATHER QUICKLY DURING THE PAST HOUR WITH SCATTERED SHOWERS AND THUNDERSTORMS FOLLOWING RATHER QUICKLY BEHIND. THE INITIAL STORMS SEEMED TO DEVELOP ALONG ALONG BOUNDARIES OR THE ESCARPMENT...BUT A MID LEVEL DISTURBANCE IS INTERACTING WITH THE BOUNDARY NEAR THE OH RIVER. ADDITIONAL MORE WIDESPREAD CONVECTION IS NEAR THE KY/IN/OH TRI STATE AREA AND SHOULD EVENTUALLY MOVE/DEVELOP EAST SOUTHEAST TOWARD OUR NORTHERN COUNTIES WHERE THE ENVIRONMENT IS MORE UNSTABLE. HOURLY POPS AS WELL AS TEMP AND DEWPOINTS WERE ADJUSTED ACCORDINGLY BASED ON THE LATEST TRENDS. AS MENTIONED EARLIER...HEAVY RAIN STILL DOES APPEAR TO BE A GREATER THREAT FROM ANY STORMS AS COMPARED TO SEVERE...ALTHOUGH MARGINALLY LARGE HAIL OR DAMAGING WIND GUSTS FROM A STRONGER STORM OR TWO CANNOT BE COMPLETELY RULED OUT. UPDATE ISSUED AT 1043 AM EDT WED APR 4 2012 CONVECTION THAT WAS ATTEMPTING TO MOVE INTO THE REGION FROM CENTRAL KY IN THE MORNING HAS DISSIPATED TO NOTHING MORE THAN SOME LOW TO MID LEVEL CLOUDINESS. THERE IS A RATHER LARGE SECTION OF THE AREA STARTING TO GET SOME SIGNIFICANT SUNSHINE. THE LINGERING VALLEY FOG AND STRATUS IN THE CUMBERLAND VALLEY HAS DISSIPATED. CONVECTIVE DEVELOPMENT TODAY WILL LIKELY HOLD OFF INTO THE EARLY TO MID AFTERNOON...OR GENERALLY LATER THAN THE 12Z NAM IS PROJECTING. THE APPROACHING BOUNDARY AS WELL AS MESOSCALE FEATURES SUCH AS DIFFERENTIAL HEATING FROM TERRAIN OR ALONG THE INTERFACES BETWEEN WHERE HEAVIER PRECIPITATION FELL ON TUE AFTERNOON/AND EVENING AND WHERE IT WAS MUCH LIGHTER OR NEARLY RAINFREEE AND ANY LEFTOVER OUTFLOWS ARE POSSIBLE POINTS WHERE DEVELOPMENT MIGHT OCCUR FIRST. THE MID LEVEL IMPULSE MOVING TOWARD THE MID ATLANTIC STATES MAY HAVE SOME FRINGE EFFECTS AS WELL THIS AFTERNOON INTO THIS EVENING IN AIDING IN SOME ORGANIZATION TO THE CONVECTION. SHEAR AND INSTABILITY PARAMETERS FORECAST BY THE MODELS APPEAR TO BE MORE OR LESS ON THE MARGINAL END OF THE SPECTRUM WITH THE FORECAST SOUNDINGS MORE MOIST WITH A BIT HIGHER PW COMPARED TO TUE. DEPENDING ON EVOLUTION OF INSTABILITY...A FEW STORM COULD PRODUCE DAMAGING WINDS AND OR MARGINALLY SEVERE HAIL AS NOTED IN THE MOST RECENT SPC OUTLOOK. HOWEVER...THE FLASH FLOOD THREAT MAY BE GREATER. THE ORIENTATION OF THE STALLED OR NEARLY STALLED OUT BOUNDARY SLOWLY SAGGING SOUTH OF THE OH RIVER AND WESTERLY FLOW...BUT PROJECTED STORM MOTION NEAR 15KT AND THE HIGH PW ON THE ORDER OF JUST UNDER 2SD ABOVE NORMAL DEFINITELY POINTS TO A THREAT FOR SOME HEAVY RAIN WHERE THUNDERSTORMS OCCUR...AS THERE COULD BE TRAINING. SOME LOCATIONS HAD SOME WATER ISSUES YESTERDAY...ESPECIALLY LETCHER COUNTY AND SOME LOCATIONS RECEIVED ABOUT 1 TO 2 INCHES OF RAIN FROM THUNDERSTORMS ON TUE AFTERNOON OR EVENING...WITH LOCALLY HIGHER AMOUNTS. GIVE ALL OF THESE FACTORS...WE WILL KEEP THE FLOOD WATCH IN EFFECT AS IS FOR THIS UPDATE. UPDATE ISSUED AT 745 AM EDT WED APR 4 2012 ISSUED A QUICK UPDATE TO ADJUST POPS IN THE NEAR TERM WITH THE LATEST EXPECTATIONS OF THIS FIRST WAVE THIS MORNING AND THEN BUILDING IT UP IN THE AFTERNOON A BIT FURTHER NORTH. IN ADDITION...UPDATED THE TEMPS...WINDS AND DEWPOINTS TO BETTER REFLECT CURRENT CONDITIONS AND TRENDS. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 340 AM EDT WED APR 4 2012 07Z SFC ANALYSIS SHOWS A LOW CENTERED OVER SOUTHERN MISSOURI WITH A WEST TO EAST WARM FRONT/ELONGATED AREA OF LOWER PRESSURE RUNNING GENERALLY ALONG THE OHIO RIVER. THIS BOUNDARY HAS REMAINED INTERMITTENTLY ACTIVE THROUGH THE NIGHT...EVEN AS THE MORE ROBUST... DIURNALLY DRIVEN...SLOW MOVING CONVECTION DIED OUT OVER EAST KENTUCKY DURING THE LATE EVENING. DO EXPECT THAT THIS REGION OF LOWER PRESSURE WILL BECOME MORE ACTIVE TOWARD DAWN IN CONJUNCTION WITH A SLOW MOVING BAND OF MID LEVEL SHORTWAVES RUNNING THROUGH THE SOUTHERN OHIO VALLEY. THE ENVIRONMENT IS RELATIVELY MOIST OVER THE AREA WITH DEWPOINTS RUNNING IN THE MID AND UPPER 50S WHILE TEMPERATURES ARE SETTLING INTO THE LOWER 60S IN MOST PLACES...EARLY THIS MORNING. THE MODELS ARE IN DECENT AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST AS THEY ALL ROLL A CLOSED AND SOMEWHAT CUT OFF LOW THROUGH THE SOUTHERN PLAINS AND TOWARDS THE LOWER OHIO VALLEY BY THURSDAY MORNING. FLAT RIDGING AND DEEP SOUTHWEST FLOW EXIST OUT AHEAD OF THIS LOW AFFECTING KENTUCKY AND THIS WILL BE SQUEEZED OFF TO THE EAST BY 12Z THURSDAY. AT THE SAME TIME...A DEEP TROUGH OVER THE NORTHEAST WILL SHIFT SLIGHTLY SOUTH. GIVEN THE MODEL SIMILARITIES ALOFT HAVE GONE WITH A BLENDED SOLUTION WITH A LEAN TOWARD THE HIGHER RESOLUTION NAM12...AND A NOD TO THE HRRR IN THE NEAR TERM... BUT TRANSLATED SLIGHTLY SOUTH IN LINE WITH THE OTHER MODELS LATTER IN THE SHORT TERM. AN ACTIVE WEATHER PERIOD IS UPON US WITH THE APPROACH OF THE UPPER LOW TO THE WEST AND THE STALLED BOUNDARY LAYING OVER NORTHERN PARTS OF EAST KENTUCKY. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP AND INCREASE THROUGH THE AREA LATER TODAY AS DIURNAL HEATING INITIATES CONVECTION...HELPED ALONG BY SFC CONVERGENCE WITH THE BOUNDARY AND SOME UPPER LEVEL DIVERGENCE. THE STEAMY BOUNDARY LAYER WILL CONTRIBUTE TO HIGH INSTABILITY TODAY WITH MID LEVEL WINDS FAVORABLE FOR MORE ORGANIZED CONVECTION. AS A RESULT...STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE THROUGH THE AREA WITH HIGH PW AIR SETTING THE STAGE FOR HEAVY RAIN FROM ANY HEALTHY STORMS. DAMAGING WINDS AND LARGE HAIL WILL BE THE MAIN THREAT FROM THESE. THE STORMS WILL BE MORE PROGRESSIVE THAN YESTERDAY...BUT TRAINING...AND PLENTY OF AREAS OF LOWER FFG AFTER YESTERDAY/S RAINS...WILL MAKE FLASH FLOODING A CONCERN LATER TODAY AND THROUGH THE FIRST PART OF THE NIGHT. ACCORDINGLY...WILL HOIST A FLASH FLOOD WATCH FOR ALL BUT OUR NORTHWEST COUNTIES. THE HEAVIER RAINS WILL DISSIPATE BY THURSDAY MORNING AS DRIER AIR SEEPS INTO THE REGION FROM THE NORTH...BUT THE THREAT OF SHOWERS AND THUNDERSTORMS WILL REMAIN THROUGH THE DAY. THE BAROCLINIC ZONE IN PLACE THROUGH THE AREA ON THURSDAY WILL KEEP THE NORTHERN COUNTIES UP TO 10 DEGREES COOLER THAN THE SOUTHERN ONES FOR HIGHS. HAVE FOLLOWED A BLEND OF THE MOS GUIDANCE THROUGH THE PERIOD ALLOWING THE MAV NUMBERS TO TEMPER THE MET/S...WITH LITTLE IN THE WAY OF TERRAIN ADJUSTMENTS GIVEN THE MOIST ENVIRONMENT. DID FAVOR THE MET POPS THROUGH THE SHORT TERM...BUT HAD THEM TRANSLATED MORE TO THE SOUTH OWING TO THE CONSENSUS FAVORING MORE SUPPRESSION OF THE FRONTAL BOUNDARY FROM THE HIGH TO THE NORTHEAST. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 305 AM EDT WED APR 4 2012 THE MODELS ARE IN GOOD AGREEMENT REGARDING THE EVOLUTION OF WEATHER SYSTEMS FOR THE DAY 4-7 PERIOD. INITIALLY...SCATTERED RAIN SHOWERS WILL BE PRESENT FROM THE TENNESSEE BORDER NORTHWARD TO THE HAL ROGERS PARKWAY AND ALONG AND NORTH OF THE HIGHWAY 80 CORRIDOR. THESE RAIN SHOWERS WILL LIKELY LINGER THROUGH 9 OR 10Z ACROSS THIS AREA ON FRIDAY MORNING...BEFORE EXITING INTO VIRGINIA BY 13Z OR SO. AFTER THAT...THE MODELS ALL AGREE THAT HIGH PRESSURE WILL BECOME FIRMLY ESTABLISHED ACROSS THE OHIO AND TENNESSEE VALLEY AREAS THROUGH SUNDAY MORNING. THE GFS AND ECMWF BOTH ARE QUICKLY MOVING A WEAK FRONTAL BOUNDARY AND UPPER LEVEL TROUGH ACROSS THE REGION ON SUNDAY. THESE FEATURES WILL JUST STRONG ENOUGH AND HAVE JUST ENOUGH MOISTURE ASSOCIATED WITH THEM TO SPARK ISOLATED TO SCATTERED RAIN SHOWERS. AT THIS TIME THE MODEL DATA INDICATE THAT THE ATMOSPHERE WILL ONLY BE ABLE TO SUPPORT ISOLATED THUNDERSTORM ACTIVITY. WITH ALL THAT IN MIND...THE INHERITED FORECAST FOR SUNDAY WAS ADJUSTED TO REFLECT PRECIPITATION CHANCE THAT WERE A GOOD DEAL LOWER...AND MORE IN LINE WITH THE LATEST MEXMOS DATA...WHICH WAS REFLECTIVE OF 20-30 PERCENT PRECIPITATION PROBABILITIES ACROSS THE BOARD. ANOTHER AREA OF WEAK HIGH PRESSURE WILL THEN BECOME ESTABLISHED ACROSS THE SUNDAY NIGHT AND MONDAY. ANOTHER EVEN MORE ILL DEFINED FRONTAL BOUNDARY AND UPPER TROUGH COMBO WILL BRING SCATTERED RAIN SHOWERS TO EASTERN KENTUCKY MONDAY NIGHT AND TUESDAY. THE WEATHER...SKY COVER...AND PRECIPITATION AMOUNT FORECASTS WERE ALL ADJUSTED BASED ON THE LOWER PRECIPITATION PROBABILITIES. ACCOUNTING FOR THE AMOUNT OF CLOUD COVER AND PRECIPITATION EXPECTED...AND WITH SOMEWHAT COOLER AIR MASSES EXPECTED TO MOVE ACROSS THE AREA...TEMPERATURES WILL BE VERY CLOSE TO NORMAL THROUGH MONDAY...AND MAY EVEN BE SEVERAL DEGREES BELOW NORMAL NEXT TUESDAY AS COOLER AIR MAKES A FAIRLY DEEP SOUTHWARD INTRUSION INTO THE EASTERN CONUS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 213 PM EDT WED APR 4 2012 A NEARLY STATIONARY FRONT NEAR THE OH RIVER IS COMBINING WITH DAYTIME HEATING AND A MID LEVEL DISTURBANCE TO BRING ISOLATED TO SCATTERED SHRA/TSRA. THROUGH AT LEAST 22Z WE EXPECTED FURTHER DEVELOPMENT AND EXPANSION OF SHOWERS AND THUNDERSTORMS THROUGH THE AREA AND SOME THAT ARE CURRENTLY UPSTREAM MAY ADVECT IN AS WELL. ATTM...WE WENT WITH VCTS AT THE START OF THE PERIOD. ANY STORM WILL BRING WITH IT AT LEAST BRIEF MVFR OR LOWER CIGS AND VIS DOWN TO IFR OR LESS IN ANY HEAVY RAIN OR HAIL. STORMS AND/OR MVFR CONDITIONS WILL BE POSSIBLE THROUGH MUCH OF THE PERIOD ALONG AND JUST BEHIND THE SAGGING FRONT. WINDS THROUGH THE PERIOD WILL BE GENERALLY FROM THE WEST AT 5 TO 10 KTS THROUGH THE FIRST 6 HRS AT THE TAF SITES AND THEN BEGIN TO SHIFT TO THE NORTH OR NORTHEAST ONCE THE BOUNDARY PASSES. && .JKL WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR KYZ058>060-068-069- 079-080-083>088-104-106>120. && $$ UPDATE...UPDATE...JP SHORT TERM...GREIF LONG TERM....AR AVIATION...JP
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1145 AM MDT WED APR 4 2012 UPDATED AVIATION .UPDATE... CLOUD COVER AND THE LINGERING EASTERLY WINDS HAS KEPT MUCH OF THE AREA A BIT COOLER THAN FORECAST. SHORT RANGE MODELS SHOW THAT EVEN WITH THIS DELAY IN THE HEATING AND THE WARMING DOWNSLOPE WINDS THAT IT WILL COME BY THIS AFTERNOON AS THE SFC LOW MOVES INTO THE NORTH CENTRAL MONTANA PLAINS AND THE WARMING WESTERLY OR SOUTHWESTERLY WINDS WILL SET-UP AND THE CLOUDINESS WILL WANE ALLOWING FOR MORE INSOLATION/HEATING. HAVE ADJUSTED THE HOURLY TEMPS TO ACCOUNT FOR THE LOWER TEMPS THAN EXPECTED THIS LATE MORNING AND THE WARMING AS THE CLOUDS BREAK THIS AFTERNOON AND THE WINDS PICK UP. OTHER PORTIONS OF THE FORECAST STILL LOOK FINE WITH RESPECT TO FIRE WEATHER CONCERNS ACROSS SW MONTANA...AND PRECIP CHANCES DUE TO AN SCATTERED SHOWER OR ISOLATED THUNDERSTORMS ACROSS NORTH CENTRAL MONTANA. RUC SHOWING CAPES NEARING 250-350J/KG AND DECENT MID LVL LAPSE RATES AROUND 8.5 DEGREES C BY THIS AFTERNOON AND SHOULD ALLOW FOR THE FORECASTED AFTN ISOLATED T-STORMS. --SCHOTT && .AVIATION... UPDATED 1800Z. WIDESPREAD MID-LEVEL CLOUDS ARE CURRENTLY EXTENDING FROM KCTB-KGTF-KLWT AND WILL DECREASE THIS AFTERNOON WITH WINDS SHIFTING TO THE SOUTH. A COLD FRONTAL PASSAGE IS EXPECTED LATER THIS AFTERNOON WITH ISOLATED SHOWERS AND THUNDERSTORMS ALONG AND BEHIND THE BOUNDARY. ANY STORMS MAY HAVE GUSTY AND ERRATIC WINDS. BEST CHANCES FOR THUNDER WILL BE AT KBZN AND KHLN. WINDS WILL BECOME WESTERLY BEHIND THE COLD FRONT WITH THE TIMING AROUND 22Z FOR KCTB AND KHLN...00Z FOR KGTF AND KBZN AND 02Z FOR KHVR AND KLWT. OVERALL...VFR CONDITIONS ARE EXPECTED HOWEVER BRIEF INTRUSIONS OF MVFR WITH SHOWERS AND POSSIBLE. MLV && .PREV DISCUSSION... /ISSUED 550 AM MDT WED APR 4 2012/ TODAY THROUGH FRIDAY...THE BEGINNING OF AN ACTIVE PERIOD OF WEATHER WILL START TODAY...AND THEN CONTINUE INTO FRIDAY. A PACIFIC COLD FRONT...CURRENTLY JUST MOVING INTO WESTERN MONTANA AT 4 AM...WILL MOVE SLOWLY EASTWARD TOWARDS CENTRAL MONTANA TODAY. EXPECT THIS FRONT TO MOVE EAST OF THE DIVIDE THIS AFTERNOON...AND THEN GRADUALLY MOVE THROUGH THE LEWISTOWN AREA THIS EVENING. MILD TEMPERATURES ARE EXPECTED AHEAD OF THE FRONT...WITH THE WARMEST LOCATIONS EXPECTED IN THE HAVRE/LEWISTOWN AREAS TODAY. AS THE FRONT MOVES EAST OF THE DIVIDE...EXPECT SCATTERED SHOWERS TO DEVELOP ALONG WITH A FEW THUNDERSTORMS. THE DYNAMICS ARE GOOD WITH THIS SYSTEM...BUT THE INSTABILITY IS LOW. SO FOR NOW...I REMOVED THE GUSTY WIND WORDING IN THE ZONES...BUT WE WILL CONTINUE TO WATCH THIS CLOSELY. AGAIN...COOLER AIR MOVES INTO THE REGION TONIGHT. AS THE MAIN STORM SYSTEM PULLS NORTHWARD INTO CANADA...A BAND OF PRECIPITATION IS EXPECTED TO DEVELOP OVER SOUTHWEST MONTANA. SOME SNOW IS LIKELY BY MORNING BETWEEN DILLON AND BIG SKY. FOR NOW...THE BEST ACCUMULATING SNOWFALL SHOULD BE ABOVE 7000 FEET...SO I WILL HOLD OFF ON AN ADVISORY FOR NOW. THE PRECIP WILL CONTINUE INTO THURSDAY OVER SOUTHWEST MONTANA...WITH JUST A FEW SHOWERS OVER CENTRAL MONTANA...WHILE THE HI-LINE AREA STAYS MOSTLY DRY ON THURSDAY AFTERNOON. AFTERNOON TEMPERATURES ON THURSDAY WILL BE CLOSE TO 20 DEGREES COOLER THAN WEDNESDAY. THEN FOR THURSDAY NIGHT AND INTO FRIDAY...BOTH THE EC/GFS MODEL PROG A STRONG AREA OF LOW PRESSURE TO DEVELOP OVER SOUTHERN WYOMING...AND THEN MOVE NORTHEASTWARD INTO THE UPPER MIDWEST. THIS TRACK WOULD ALLOW FOR HEAVY SNOW TO DEVELOP IN THE MOUNTAINS OF SOUTHWEST MONTANA ON THURSDAY NIGHT AND THEN SPREAD NORTHWARD INTO CENTRAL MONTANA BY FRIDAY MORNING. THE HEAVIEST SNOWFALL SHOULD OCCUR IN THE MOUNTAINS WITH THIS SYSTEM...BUT SEVERAL INCHES OF SNOW ARE POSSIBLE AT LOWER ELEVATIONS IN SOUTHWEST/CENTRAL MONTANA. THUS A WINTER STORM WATCH HAS BEEN ISSUED FOR ALL ELEVATIONS. AFTERNOON TEMPERATURES ON FRIDAY WILL CONTINUE THE COOLING TREND...WITH THE CLOUDS/PRECIP...MOST AREAS WILL ONLY SEE HIGHS IN THE 30S. BRUSDA FRIDAY NIGHT THROUGH WEDNESDAY...MODELS ARE IN FAIRLY GOOD AGREEMENT DURING THE PERIOD SO CONFIDENCE IN THE FORECAST IS ABOVE AVERAGE. FRIDAY NIGHT THE UPPER TROUGH OVER EASTERN MONTANA WILL MOVE SLOWLY EAST AND EXPECT SNOW TO DIMINISH. SATURDAY NORTHWEST FLOW IS EXPECTED ALONG WITH SOME RESIDUAL MOISTURE. DID NOT CHANGE THE INHERITED FORECAST WHICH HAD A SLIGHT CHANCE OF PRECIPITATION OVER THE PLAINS WITH A CHANCE OF SNOW OVER THE MOUNTAINS. THEREAFTER THE FORECAST AREA WILL BE UNDER THE INFLUENCE OF A STRONG UPPER RIDGE WHICH WILL MOVE OVER CENTRAL MONTANA MONDAY. THIS WILL RESULT IN A WARMING TREND WITH HIGHS REACHING THE MID 50S TO MID 60S ON MONDAY. MODELS DIFFER SOME ON HOW FAST THE UPPER RIDGE MOVES EAST THEREAFTER BUT IT LOOKS LIKE WARM TEMPERATURES WILL CONTINUE INTO MIDWEEK. AS FOR PRECIPITATION THE RIDGE SHOULD KEEP THE AREA DRY SATURDAY NIGHT THROUGH TUESDAY WITH THE POSSIBLE EXCEPTION OF THE MOUNTAINS OF THE ROCKY MOUNTAIN FRONT. MODELS ARE POINTING TO SOME INCREASE IN MOISTURE BY WEDNESDAY OR WEDNESDAY NIGHT SO WENT WITH A SLIGHT CHANCE OF SHOWERS FOR THE LOWER ELEVATIONS AND A CHANCE OF RAIN OR SNOW SHOWERS FOR THE MOUNTAINS BY LATE WEDNESDAY. BLANK && .PRELIMINARY POINT TEMPS/POPS... GTF 69 30 46 29 / 20 20 20 40 CTB 64 27 45 24 / 40 40 20 10 HLN 71 29 46 29 / 20 10 30 50 BZN 66 27 43 27 / 10 20 50 60 WEY 38 21 37 21 / 10 40 60 70 DLN 61 25 41 26 / 20 10 50 60 HVR 74 31 51 27 / 10 30 10 10 LWT 70 29 43 27 / 10 10 30 50 && .TFX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM THURSDAY EVENING THROUGH FRIDAY EVENING BEAVERHEAD...BROADWATER...CASCADE...FERGUS...GALLATIN... JEFFERSON...JUDITH BASIN...MADISON...MEAGHER. RED FLAG WARNING UNTIL 9 PM MDT THIS EVENING FOR ELEVATIONS BELOW 6000 FEET FOR GALLATIN...MADISON...MEAGHER. && $$ UPDATE...SCHOTT SHORT TERM...BRUSDA LONG TERM...BLANK AVIATION...MLV WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1136 AM MDT WED APR 4 2012 .UPDATE... UPDATE TO PREVIOUS PACKAGE RELATIVELY MINOR. INCLUDES LOWERING 1ST PERIOD POPS A BIT FOR REMAINING AREAS...RAISING 1ST PERIOD TEMPS JUST A FEW DEGREES SOME LOCALES AND RATCHETING BACK AMT OF CLOUDS FOR CENTRAL AND NE SECTIONS FOR TODAY. 43 && .PREV DISCUSSION...300 AM MDT WED APR 4 2012... WRAP AROUND/JET RELATED PRECIPITATION CONTINUING OVER EASTERN HALF OF NEW MEXICO ATTM. LATEST RUC SHOWS UPPER LOW WILL MOVE VERY SLOWLY THIS MORNING...CENTERED OVER THE NORTHERN TX PANHANDLE BY NOON. RAIN WAS INDICATED TO BE THE PREDOMINANT PRECIPITATION TYPE WITH THE WEST TO EAST ORIENTED BAND STRETCHING ACROSS LINCOLN COUNTY TO NEAR MILNESAND. WITH TEMPS NEAR FREEZING...SNOW WAS ASSOCIATED WITH THE WRAP AROUND ECHOES FROM ANGEL FIRE TO RATON AND CLAYTON. EXPECT MINIMAL ACCUMULATIONS AND IMPACTS WITH THIS...AS COMPARED TO THE LAST 36 HOURS. OTHERWISE...AREAS OF LOW CLOUDS AND FOG WILL PLAGUE THE RIO GRANDE VALLEY EASTWARD THIS MORNING. THE LINGERING PRECIPITATION SHOULD BE OVER WITH BY THIS AFTERNOON. HIGH TEMPERATURES WILL BE WARMER OVERALL TODAY...AND ALTHOUGH THE SURFACE GRADIENT ISN/T VERY STRONG COULD NOT RULE OUT SOME NORTHWEST TO NORTHERLY BREEZES IN THE EAST...BUT ESPECIALLY NEAR THE TEXAS BORDER WHERE FORECAST H7 WINDS ARE AROUND 30KT. MODELS INDICATE HIGH LEVEL MOISTURE INCREASING TONIGHT ...MAYBE ENOUGH TO KEEP FOG FROM DEVELOPING OVER AREAS WHICH RECEIVED SIGNIFICANT SNOWFALL MONDAY NIGHT/TUESDAY. CONFIDENCE NOT THAT GREAT BUT WENT AHEAD AND PUT PATCHY FOG IN THE GRIDS FOR THE SANGRE DE CRISTO MOUNTAINS/NORTHEAST HIGHLANDS AND OVER TOWARDS CAPULIN/FOLSOM...WHERE MELTING SHOULD CONTINUE DURING THE DAY TODAY. THURSDAY AND FRIDAY FEATURE A WARMING TREND WITH TEMPERATURES BACK ABOVE NORMAL. INCREASING SOUTHWEST FLOW ALOFT IS ANTICIPATED AS A SYSTEM PASSES THROUGH THE NORTHERN ROCKIES. THIS IS MUCH FARTHER NORTH THAN SHOWN A COUPLE OF DAYS AGO...SO WINDS SHOULDN/T GET TOO UNRULY. A SURFACE FRONT DROPPING INTO THE PLAINS ON SATURDAY APPEARS TO BE ENOUGH OF A MECHANISM TO IGNITE A FEW THUNDERSTORMS BUT INITIALLY MAINLY TO OUR EAST. HOWEVER...AS SURFACE HIGH PRESSURE SETTLES SOUTHWARD INTO THE CENTRAL/SOUTHERN PLAINS...LOW LEVEL MOISTURE INCREASES INTO OUR EASTERN PLAINS. THE GFS IN PARTICULAR HAS BEEN PRETTY ENERGETIC DEVELOPING WIDESPREAD AMOUNTS OF PRECIPITATION SUNDAY THROUGH MONDAY OVER THE EASTERN HALF OF NEW MEXICO...DESPITE THE REGION BEING UNDER A RATHER SHARP RIDGE ALOFT. BASED ON THE FORECAST POSITION OF THE RIDGE AXIS...THE ARGUMENT COULD BE MADE THAT THE EASTERN SIDE OF THE STATE WILL BE UNDER NORTHWEST FLOW ALOFT BUT IT WILL BE PRETTY WEAK. THE LATEST 00Z ECMWF IS EVEN JUMPING ON THIS IDEA THOUGH NOT QUITE AS EXTREME. CURRENT POP/WX GRIDS HAVE THIS TREND COVERED AT LEAST FOR NOW. THE MIDDLE TO LATE WEEK PERIOD NEXT WEEK APPEARS TO BECOME MORE UNSETTLED AS AN UPPER TROUGH PUSHES INTO THE GREAT BASIN AND HEADS FOR NEW MEXICO. THERE COULD BE POTENTIAL FOR A CLOSED LOW TO DEVELOP AS IT REACHES THE EASTERN SLOPES OF THE ROCKIES...BASED ON GFS/ECMWF. THERE/S STILL QUITE A BIT OF TIME FOR CHANGES...CONSIDERING THE NOW EXITING STORM SYSTEM WAS SUPPOSED TO BE DRY AND WINDY UNTIL ONLY A COUPLE OF DAYS PRIOR. .AVIATION...AREAS OF LIGHT SNOW WILL AFFECT PORTIONS OF NORTHEAST NM THROUGH 16Z RESULTING IN MVFR/IFR CIGS/VSBYS AT TIMES... ESPECIALLY BETWEEN KLVS AND KRTN...AND NEAR THE NE NM/SE CO LINE. ELSEWHERE... LOW CLOUDS AND FOG OR FREEZING FOG WILL CONTINUE TO DEVELOP/EXPAND THROUGH DAYBREAK ESPECIALLY IN THE VALLEYS OF NC/NW NEW MEXICO THAT RECEIVED SIGNIFICANT PRECIP DURING THE PAST 24 HOURS. HIGHEST CONFIDENCE IN MVFR/BRIEF IFR CONDITIONS AT KSAF AND KABQ...AS WELL AS KSKX AND THE UPPER RIO GRANDE VALLEY. PRECIP ENDING AND CIGS RISING ACROSS NE NM BY MID- TO LATE MORNING AS THE STORM SYSTEM PULLS AWAY AND LOW LEVEL DOWNSLOPE FLOW AND VFR CONDITIONS RETURN. ELSEWHERE...ASIDE FROM MORNING LOW CLOUDS/FOG OR FREEZING FOG...VFR CONDITIONS EXPECTED. KJ NEXT AVIATION DISCUSSION SCHEDULED FOR 21Z. .FIRE WEATHER...TEMPERATURES QUICKLY REBOUND TODAY...ALTHOUGH MAXES WILL REMAIN JUST SHY OF SEASONAL AVERAGES ACROSS MUCH OF THE CENTRAL AND EAST. THE NORTHEAST WILL BE SLOWEST TO RECOVER AND HIGHS THERE WILL BE 5 TO 10 DEGREES BELOW NORMAL. WITH THE WARMING....AFTERNOON HUMIDITY VALUES WILL TREND DOWNWARD IN A BIG WAY ESPECIALLY CENTRAL AND NORTH CENTRAL AREAS. RH VALUES LOOK TO BOTTOM OUT IN THE TEENS ACROSS THE SOUTH AND WEST...WITH MOSTLY 20S TO NEAR 40 ELSEWHERE. VENTILATION WILL BE VERY GOOD TO EXCELLENT FOR A VAST MAJORITY OF THE AREA LATER TODAY THANKS TO DEEP LAYER NORTHWEST FLOW ON THE BACKSIDE OF THE DEPARTING STORM SYSTEM. THIS WILL TRANSLATE TO MODERATE NORTHWEST BREEZES FOR MANY AREAS...ESPECIALLY EAST OF THE CENTRAL MOUNTAIN CHAIN AND PORTIONS OF WEST CENTRAL NEW MEXICO. A BRISK NORTH TO NORTHWEST WIND WILL ALSO DEVELOP ACROSS THE NORTHEAST ONCE AREAS OF LIGHT SNOW END AFTER MID OR LATE MORNING. WEAK HIGH PRESSURE ALOFT SLIDES OVER THE AREA TONIGHT. GIVEN THE EFFECTS OF MELTING SNOW ON BOUNDARY LAYER MOISTENING...LOW CLOUDS AND FOG/FREEZING FOG MAY REVISIT THE VALLEYS OF NORTHERN NEW MEXICO TOWARD DAYBREAK THURSDAY. OTHERWISE THE DRYING AND WARMING TREND WILL CONTINUE THROUGH THE END OF THE WORK WEEK. VENTILATION RATES WILL BE IN THE EXCELLENT CATEGORY BOTH DAYS FOR A VAST MAJORITY OF THE AREA. AFTERNOON AND EVENING WINDS WILL BE MORE NOTICEABLE THURSDAY AND ESPECIALLY FRIDAY AS MID-LEVEL GRADIENTS TIGHTEN AND BECOME MORE WEST TO SOUTHWEST BY FRIDAY. WESTERN AREAS AND THE NORTHEAST WILL BE FAVORED FOR BREEZY CONDITIONS THURSDAY AFTERNOON WITH MORE WIDESPREAD BREEZY/WINDY CONDITIONS ON FRIDAY. HOWEVER...RECENT MODEL TRENDS NOW SUPPORT LESS OVERALL WIND IMPACTS ON FRIDAY AS THE MAIN SHORTWAVE IS LIFTING OUT FARTHER NORTH. EVEN SO...DEEP MIXING DURING THE AFTERNOON/EVENING WILL BRING THE HIGHER MOMENTUM AIR TO THE SURFACE AND COMBINED WITH LOWERING RH/S WILL RESULT IN AN INCREASING THREAT FOR LOW END CRITICAL FIRE WEATHER GROWTH CONDITIONS MAINLY ACROSS THE EAST CENTRAL PLAINS. WEAK RIDGE ALOFT INDICATED SATURDAY AND SUNDAY WITH LESS WIND AREAWIDE...THOUGH STRENGTHENING SOUTH OR SOUTHEAST SURFACE GRADIENTS LIKELY ACROSS THE FAR EAST. WE WILL BE MONITORING LOW LEVEL MOISTURE RETURN ACROSS PORTIONS OF SOUTH CENTRAL AND SOUTHEAST NEW MEXICO LATE IN THE WEEKEND INTO EARLY NEXT WEEK...AS THE LARGE SCALE WIND PATTERN IS FAVORABLE TO ALLOW FOR A SUBTLE BUT POTENTIALLY SIGNIFICANT INCREASE BEGINNING SUNDAY. THIS COULD RESULT IN A THREAT OF HIGH BASED SHOWERS OR VIRGA AT A MINIMUM...AND POSSIBLY DRYLINE-ENHANCED THUNDERSTORMS ACROSS THE FAR EAST. HOW FAR WEST AND NORTH THIS VIRGA THREAT EXPANDS IS VERY UNCERTAIN...BUT AREAS ALONG AND EAST OF THE CENTRAL MOUNTAIN CHAIN WILL BE VERY SUSCEPTIBLE AND CLIMATOLOGICALLY-FAVORED. KJ && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 43
AREA FORECAST DISCUSSION
NWS RALEIGH NC
150 PM EDT WED APR 4 2012 .SYNOPSIS... A STRONG BACK DOOR COLD FRONT WILL APPROACH FROM THE NORTH THIS EVENING...THEN SURGE SOUTH THROUGH THE AREA LATE TONIGHT AND THURSDAY MORNING. MUCH COOLER TEMPERATURES ARE EXPECTED IN THE WAKE OF THE FRONT THURSDAY AND FRIDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1000 AM WEDNESDAY... A MODEST MID-LEVEL SHORTWAVE MOVING THROUGH CENTRAL NORTH CAROLINA THIS MORNING HELPED TO INITIATE ISOLATED DEEP CONVECTION TOWARD KIXA AND KRWI AROUND SUNRISE...WITH JUST ENOUGH ELEVATED INSTABILITY AND STEEP LAPSE RATES NOTED AT LEAST ON FORECAST SOUNDINGS...SUCH AS THE KFAY NAM BUFR SOUNDING FOR 12Z TODAY...TO PROVIDE FOR ISOLATED SHOWERS AND THUNDERSTORMS. THE PRECIPITATION STARTED TO WANE DURING THE MID-MORNING HOURS...AND THIS PRECIPITATION AND ITS EVOLUTION WAS VERY WELL DEPICTED ON SOME OF THE 00Z WRF MODELS. WITH MSAS SHOWING A RELATIVE MINIMUM OF SURFACE-BASED LIFTED INDICES AND THETA-E OVER MUCH OF CENTRAL NORTH CAROLINA...AND IN SUBSIDENCE BEHIND THE MID-LEVEL WAVE AS FORECAST BY BOTH THE LATEST RUC AND NAM...THERE SHOULD BE LOW CHANCES FOR REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS UNTIL LATER IN THE AFTERNOON. AT THAT POINT...BUFR SOUNDINGS FROM THE NAM SHOW AVAILABLE INSTABILITY STARTING TO INCREASE...AS LOW-LEVEL CIN IS OVERCOME AND LAPSE RATES ACTUALLY STEEPEN...TO AT LEAST 7C/KM FROM 1000-500MB ON BOTH THE LATEST NAM AND RUC. WHILE JET SUPPORT STAYS WELL TO THE NORTH IN THE MID- AND UPPER-LEVELS... AND LOW-LEVEL WINDS ARE NOT FORECAST TO BE TOO STRONG...ONLY ABOUT 10-15 KNOTS FROM 925MB THROUGH 850MB WHICH IS COINCIDENT WITH SOME OF THE LIGHTER WINDS ALOFT ON THE LATEST LOCAL AMDAR SOUNDINGS... 850MB CONVERGENCE INCREASES AND INVERTED-V-TYPE BUFR SOUNDINGS TAKE SHAPE BY LATE IN THE AFTERNOON...CONTINUING INTO THE EVENING. WITH THE FRONT TO THE NORTH AND SURFACE TROUGHINESS DEVELOPING TO THE WEST DURING THE DAY...THE LIKELY SCENARIO IS THAT DEEPER CONVECTION WILL DEVELOP TO OUR NORTH AND WEST AND MOVE SOUTHEAST ACROSS THE AREA EITHER PROPAGATING OR REGENERATING OFF OF ITS COOL POOL. SOME OF THE WRF GUIDANCE SUGGESTS MUCH OF THE PRECIPITATION STAYING NEAR THE VIRGINIA BORDER AND NEAR OR WEST OF THE YADKIN RIVER THROUGH LATE AFTERNOON...WHILE OTHERS SHOW A SURGE IN SHOWERS AND STORMS MOVING SOUTHEAST ALONG AND SOUTH OF U.S. 64. WHILE LOCATION IS UNCERTAIN...A LIKELY SCENARIO IS SOME DEVELOPMENT OF A CLUSTER OF STORMS MOVING OVER SOME PART OF CENTRAL NORTH CAROLINA LATE TODAY AND THIS EVENING WITH A POTENTIAL FOR DAMAGING WINDS. WET-BULB ZERO VALUES ARE LOW...SO HAIL IS ALSO A THREAT. THE CURRENT HAZARDOUS WEATHER OUTLOOK DISCUSSES THE TIMING AND PRIMARY THREAT OF DAMAGING WINDS WELL. HIGH TEMPERATURES SHOULD REACH THE MID 80S OVER MUCH OF CENTRAL NORTH CAROLINA. THE AFTERNOON HIGH MAY COME CLOSE TO THE RECORD AT KRDU...WHERE IT IS A COOL 87 DEGREES RELATIVE TO SURROUNDING DAYS. THE KGSO RECORD IS 86...A LESSER CHANCE OF REACHING THAT ONE. THOUGH INSTABILITY WILL BEGIN TO WANE AFTER SUNSET...ADDITIONAL CONVECTION WILL BE POSSIBLE IN ASSOCIATION WITH THE BACK DOOR COLD FRONT PROGRESSING SOUTH THROUGH VIRGINIA INTO CENTRAL NORTH CAROLINA OVERNIGHT. WILL MAINTAIN A SLIGHT CHANCE (20%) NORTH TO LOW CHANCE (30%) SOUTH FOR THE LATE NIGHT HOURS...WITH ISOLATED THUNDERSTORMS MORE LIKELY IN SOUTHERN PORTIONS OF THE AREA. EXPECT LOWS TO RANGE FROM THE LOWER/MID 50S IN THE NORTH AND NORTHEAST TO THE UPPER 50S AND LOWER 60S IN THE SOUTH. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... AS OF 310 AM WEDNESDAY... AN UPPER LOW CURRENTLY LIFTING OUT OF NORTHEAST NM WILL DRIFT EAST ACROSS THE MID MS RIVER VALLEY WEDNESDAY NIGHT... AND THEN BEGIN TO MOVE SOUTHEAST TOWARD AL/GA ON THURSDAY AS IT APPROACHES THE SOUTHERN EDGE OF BROAD CYCLONIC FLOW OVER THE NORTHEAST US. A COLD FRONT AND/OR REMNANT CONVECTIVE OUTFLOW SHOULD BE NEAR THE NC/SC BORDER BY 12Z THURSDAY...WHERE A FEW ISOLATED SHOWERS CANNOT BE RULED OUT DURING THE MORNING HOURS. HOWEVER...MOST OF THE CENTRAL NC SHOULD BE DRY THROUGH THURSDAY AFTERNOON AS A SURFACE HIGH PRESSURE RIDGE SETTLES IN BEHIND THE FRONT AND A WEAK SHORTWAVE UPPER RIDGE SHIFTS ACROSS NC AHEAD OF THE APPROACHING UPPER LOW. WHILE FORECAST SOUNDINGS SUGGEST THE BOUNDARY LAYER WILL BE SLOW TO SATURATE UNTIL LATER THURSDAY EVENING...THE LOW LEVEL COLD ADVECTION BEHIND THE FRONT SHOULD BE HELP TO LOCK IN STRATUS AT 2-3K FT WHERE MOISTURE WILL ALREADY EXIST. THUS...TEMPS WILL STRUGGLE TO RISE UNTO THE LOW TO MID 60S...A GOOD 20 DEGREES COOLER THAN WEDNESDAY. FORCING FOR ASCENT...IN THE FORM OF INCREASING DIVERGENCE ALOFT...WEAK LOW LEVEL WARM ADVECTION AND 60-80M HEIGHT FALLS...WILL ARRIVE THURSDAY EVENING AS THE UPPER LOW DIVES THROUGH AL/GA. WHILE THERE HAS BEEN GOOD MODEL CONSISTENCY IS THE GENERAL TRACK OF THE UPPER AND SURFACE LOWS...THERE ARE STILL 100-200 MILE DIFFERENCES THAT WILL IMPACT HOW FAR NORTH INTO NC BETTER RAIN COVERAGE WILL EXTEND. MOST OF THE SHOWERS WILL PASS TO OUR SOUTH THURSDAY NIGHT AS THE SURFACE LOW DEVELOPS AND MOVES TO NEAR SAVANNAH BY 06-12Z FRIDAY. HOWEVER...A SHORTWAVE DROPPING SOUTH OUT OF EASTERN CANADA INTO THE MID-ATLANTIC STATES SHOULD HELP DRAW MOISTURE NORTH INTO THE VICINITY OF THE 925-850MB FRONT WHICH IS FORECAST TO LIE ACROSS THE CAROLINAS. MODELS HAVE BEEN SHOWING AN AREA OF INCREASE LOW LEVEL FGEN DEVELOPING OVER NC LATER FRIDAY NIGHT...SO WHILE THE BEST SURFACE CONVERGENCE AND UPPER FORCING WILL BE JUST TO OUR SOUTH...WE SHOULD SEE PRECIP EXPAND AND INTENSIFY NORTHWARD ACROSS SOUTHERN AND EASTERN NC OVERNIGHT. WE DO NOT EXPECT ANY CONVECTION THURSDAY NIGHT AS LOW LEVELS WILL BE STABLE...MID LEVEL LAPSE RATES WILL BE WEAK... AND THE STRONGEST UPPER FORCING WILL BE TO OUR SOUTH. HOWEVER...IF THE SURFACE LOW TRACKS SLIGHTLY NORTH OF THE CURRENT FORECAST...THERE COULD BE ENOUGH INSTABILITY ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS TO SUPPORT A FEW ISOLATED THUNDERSTORMS. FORECAST POPS ARE ALREADY HIGH ACROSS THE SOUTH AFTER 21Z THURSDAY...EXPANDING NORTHWARD AFTER 03Z...WHICH SEEMS SUFFICIENT FOR THE CURRENT FORECAST PACKAGE. LOWS IN THE UPPER 40S. THE SURFACE LOW SHOULD BE OFF THE SC COAST BY 12Z FRIDAY..WITH PRECIP ENDING FROM WEST TO EAST DURING THE DAY. THE MSLP GRADIENT ON THE BACK SIDE OF THE SURFACE LOW WILL BE FAIRLY TIGHT...WITH MOST MODELS SHOWING A 15-20KT NORTHEASTERLY WIND OVER THE COASTAL PLAIN FRIDAY MORNING. THE DEPARTING LOW WILL ALSO DRAW DRIER AIR IN FROM THE NORTH AS WINDS BEGIN TO TURN TO NORTH-NORTHWESTERLY FRIDAY AFTERNOON. FORECAST SOUNDINGS NOW SHOW MOST OF THE CENTRAL BREAKING OUT FRIDAY...ALTHOUGH MODELS OFTEN HAVE A TENDENCY TO SCOUR LOW LEVEL MOISTURE TOO QUICKLY IN THE ABSENCE OF A FRONTAL SYSTEM. BECAUSE OF THIS...THE HIGH TEMP FORECAST FOR FRIDAY IS SOMEWHAT UNCERTAIN...BUT IT IS POSSIBLE THAT AREA SIN THE WEST COULD BREAK OUT AND BE AS WARM IF NOT WARMER THAN AREAS IN THE EAST. WILL FORECAST HIGHS GENERALLY AROUND 60. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 350 AM WEDNESDAY... HIGH PRESSURE OVER THE GREAT LAKES WILL BRIEFLY BUILD SOUTH ACROSS MUCH OF THE EASTERN US THIS WEEKEND...WHILE SEVERAL SHORTWAVES OVER EASTERN CANADA AND THE NORTHERN US WRAP UP OVER NEW ENGLAND AND LEAD TO A DEEP TROUGH ALONG THE EAST COAST NEXT WEEK. RAIN CHANCES APPEAR TO BE LOW BUT ALSO LESS PREDICTABLE DUE TO THE NORTHWESTERLY FLOW REGIME...ESPECIALLY FROM SUNDAY NIGHT ONWARD. HIGHS WARMING INTO THE LOW TO MID 70S BY SUNDAY WILL DROP BACK INTO THE 60S FOR THE FIRST HALF OF NEXT WEEK. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 150 PM WEDNESDAY... PRIMARY IMPACT THROUGH THE 18Z VALID TAF PERIOD WILL BE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. ALREADY DURING THE EARLY AFTERNOON SHOWERS WERE DEVELOPING CLOSER TO THE HIGHER ELEVATIONS AND THE COLD FRONT...AND THESE SHOULD CONTINUE TO DEVELOP AND INCREASE IN COVERAGE AS THEY MOVE SOUTHEAST DURING THE AFTERNOON. EXPECT AT ALL TAF SITES POTENTIALLY FOR LOCALLY GUSTY WINDS WITH ANY THUNDERSTORM AT OR ABOVE 30KT...WITH BRIEFLY IFR CONDITIONS. SUCH CONDITIONS SHOULD DIMINISH BY 03Z IN CENTRAL NORTH CAROLINA. OVERNIGHT INTO EARLY THURSDAY...WINDS WILL QUICKLY VEER TO NORTHEAST BEHIND A COLD FRONT...WITH PATCHY RAIN EXPECTED UNDER CONSIDERABLE CLOUDS IN THE VFR RANGE. BEYOND THE 18Z VALID TAF PERIOD...A COLD FRONT WILL LIE JUST SOUTH OF CENTRAL NORTH CAROLINA BY MID-MORNING THURSDAY. THUNDERSTORMS MAY DEVELOP ALONG AND NEAR THE FRONT LATE THURSDAY AFTERNOON AND EVENING...POSSIBLY GETTING CLOSE TO KFAY BUT LIKELY REMAINING JUST SOUTH OF THERE. BEST POTENTIAL FOR IFR LOW CLOUDS WILL BE THURSDAY NIGHT INTO EARLY FRIDAY...AND THEN PARTICULARLY TOWARD KFAY...AND EXPECT THE LIKELIHOOD OF RAIN THURSDAY NIGHT. CONDITIONS GRADUALLY IMPROVE FRIDAY INTO SATURDAY...WITH PREDOMINANT VFR CONDITIONS OVER THE WEEKEND INTO EARLY NEXT WEEK. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...DJF/VINCENT SHORT TERM...SMITH LONG TERM...SMITH AVIATION...DJF
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
112 PM CDT WED APR 4 2012 .UPDATE... 18Z TAF DISCUSSION. && .AVIATION... LATEST SATELLITE IMAGERY SHOWS CUMULUS NOW DEVELOPING ACROSS THE MID STATE WITH TCU/ISO -SHRA FORMING ON THE PLATEAU JUST EAST OF THE CWA BORDER. SHORT TERM GUIDANCE SUCH AS THE HRRR INDICATES SOME WIDELY SCATTERED SHRA/TSRA SHOULD DEVELOP AROUND 21Z ACROSS THE CWA...BUT WITH LESS COVERAGE THAN MODELS HAVE INDICATED IN PREVIOUS RUNS. WITH THE REDUCED CONFIDENCE IN PRECIP COVERAGE WILL ONLY SHOW VCTS AT AREA AIRPORTS BETWEEN 21-03Z...WITH TEMPO TSRA AND MVFR CIGS AT CSV WHERE CONVECTION IS MORE PROBABLE. ANY CONVECTION TO DIMINISH BY LATE EVENING WITH VFR CONDITIONS UNTIL 08-10Z WHEN GUIDANCE INDICATES SOME PATCHY MVFR FOG AT CKV/BNA AND MVFR/IFR CIGS/FOG AT CSV. && .PREV DISCUSSION... /ISSUED 957 AM CDT WED APR 4 2012/ UPDATE...SOME MINOR ADJUSTMENT WILL BE MADE. SKIES WERE PARTLY TO MOSTLY SUNNY THIS MORNING. SUNSHINE WILL PROBABLY PUSH TEMPS A LITTLE WARMER THAN PREVIOUS FORECAST...SO WILL BUMP THEM UP A DEGREE OR 2. CLOUDS WILL THICKEN WITH INCREASING RAIN CHANCES THIS AFTERNOON...MAINLY AFTER 2 PM. COVERAGE WILL BE SCATTERED FOR THE MOST PART...BUT MORE NUMEROUS OVER THE WEST COUNTIES WHERE DEEPER MOISTURE WILL BE PRESENT. WE STILL HAVE A SLIGHT RISK FOR SEVERE STORMS WITH BRIEF WIND GUSTS OR MARGINALLY SEVERE HAIL THE MAIN CONCERNS. 13 PREV DISCUSSION... /ISSUED 502 AM CDT WED APR 4 2012/ AVIATION 12Z DISCUSSION... FRONTAL BOUNDARY WILL SAG SOUTHWARD TOWARD THE MID STATE THROUGH THE TAF PD. AS A RESULT...SCATTERED SHOWERS AND TSTMS WILL DEVELOP BY THIS AFTERNOON. SOME OF THIS ACTIVITY WILL PERSIST INTO THE EVENING AS THE UPPER RIDGE AXIS WILL BE EAST OF TN BY LATE EVENING. OTW...CIGS/VSBYS WILL LOWER TO IFR LEVELS AFT 06Z. 21 PREV DISCUSSION... /ISSUED 312 AM CDT WED APR 4 2012/ DISCUSSION... WEAK FRONTAL BOUNDARY CONTINUES TO HANG OUT IN THE SOUTHERN OH VALLEY THIS MORNING...WITH NOISY FLOW ALOFT PROVIDING NUMEROUS SHORTWAVES/IMPULSES MOVING ABOUT. MODERATE MOISTURE ALREADY SITUATED OVER THE REGION AND MARGINAL INSTABILITY ALLOWING A FEW ISO SHOWERS TO POP UP. SERIES OF SHORTWAVES/IMPULSES WILL CONTINUES TO CROSS THE MID- SOUTH TODAY/TONIGHT AHEAD OF CLOSED UPPER LOW CURRENTLY IN THE PLAINS. ADDITIONALLY...WEAK FRONTAL BOUNDARY TO THE NORTH WILL SINK SOUTH AND SETUP VERY NEAR THE KY/TN BORDER TOWARD 00Z. INSTABILITY THIS AFTERNOON EXPECTED TO INCREASE AS BOUNDARY APPROACHES SUCH THAT SHWRS/STORMS SHOULD BECOME QUITE NUMEROUS WITH SOME STORMS POSSIBLY BECOMING STRONG TO SEVERE. UPPER LOW MOVES INTO THE MS RIVER VALLEY LATE TONIGHT AND DESPITE FRONTAL BOUNDARY DROPPING DOWN OVER THE CWA...BRIEF DRY SLOTTING LIKELY TO REDUCE PCPN...ESPECIALLY 06-12Z. ON THU HOWEVER...SHWR/ STORM ACTIVITY EXPECTED TO GET BACK IN FULL GEAR AS COLD FRONT PASSES EARLY IN THE DAY FOLLOWED BY UPPER LOW LATE AFTERNOON/EARLY EVE. THU NIGHT UPPER LOW MOVES WELL EAST AS DOES FRONTAL BOUNDARY...BRINGING ABOUT DRYING AND END OF PCPN FOR THIS SEGMENT. UPPER RIDGE BUILDS IN BEHIND UPPER LOW PROVIDING DRY WX FRI/SAT BUT A WEAK FRONT WILL PASS ON SUN. MOISTURE RETURN AHEAD OF BOUNDARY WILL BE MINIMAL THUS STORMS ASSOCIATED EXPECTED TO BE ISO. BEHIND THIS FRONT...UPPER TROUGH WILL PASS MON NIGHT BUT MOISTURE AGAIN WILL BE VERY LIMITED. NO POPS PLANNED SUN NIGHT-WED AT THIS TIME. TEMPS WILL GO THROUGH A BIT OF A COOLING TREND. AFTER TODAY THEY WILL WORK BACK TO MORE NEAR NORMAL...POSSIBLY GOING BELOW NORMAL EARLY NEXT WEEK. 07 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 55
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
318 PM CDT WED APR 4 2012 .SHORT TERM...TONIGHT THROUGH SATURDAY 318 PM CDT WED APR 4 2012 MAIN EMPHASIS OF FORECAST WILL BE ON FREEZE CONDITIONS THE NEXT COUPLE OF NIGHTS ALONG WITH LOW DAYTIME RELATIVE LEVELS THURSDAY AND FRIDAY. WATER VAPOR IMAGERY AND RUC 500MB ANALYSIS SHOW A HIGHLY AMPLIFIED MID-LEVEL RIDGE IN PLACE FROM THE NORTHERN PLAINS INTO MANITOBA AND HUDSON BAY. MEANWHILE...A CLOSED/CUTOFF LOW WAS SLOWLY MOVING EAST INTO OKLAHOMA. AT THE SURFACE...HIGH PRESSURE WAS CENTERED OVER WESTERN ONTARIO. DRY/COOL NORTHEAST FLOW WAS RESULTING ACROSS THE AREA TODAY UNDER SUNNY SKIES WITH TEMPERATURES IN THE UPPER 50S TO MIDDLE 60S AND DEWPOINTS WAY DOWN IN THE 20S. 04.12Z NAM/GFS SHOWING GOOD AGREEMENT THROUGH FRIDAY...BUT THEN SOME DIFFERENCES REGARDING THE STRENGTH OF THE MID-LEVEL TROUGH AND SURFACE COLD FRONT CROP UP SATURDAY. THE 04.09Z SREF WAS GENERALLY USED FOR THIS TIME FRAME. FOR TONIGHT THE MAIN STORY WILL BE CLEAR/DRY CONDITIONS LEADING TO A RAPID DROP OFF IN TEMPERATURES. WITH THE RIDGE AXIS BUILDING SOUTHWARD INTO THE REGION...LOOKS LIKE WINDS WILL TAPER OFF TO LESS THAN 5 MPH MOST PLACES WHICH WILL ALLOW TEMPERATURES TO FALL OFF INTO THE MIDDLE 20S TO MIDDLE 30S. PLAN ON THE COLDEST AIR TO BE OVER THE FAVORED COLD SPOTS ALONG/NORTH OF THE I-94 CORRIDOR. AS SUCH...WILL KEEP FREEZE WARNING HOISTED FOR THIS AREA FROM 2 AM THROUGH 8 AM THURSDAY. HIGH PRESSURE WILL CONTINUE TO BE THE DOMINATING WEATHER FEATURE THROUGH FRIDAY WITH PREVAILING DRY CONDITIONS. CONCERN WILL AGAIN BE ON THE NEED FOR FREEZE HEADLINES LATE THURSDAY NIGHT INTO FRIDAY MORNING WITH LOWS DIPPING AGAIN INTO THE MIDDLE 20S AND LOWER 30S ACROSS MUCH OF THE AREA...WITH MID/UPPER 20S MORE PREVALENT EAST OF THE MISSISSIPPI RIVER. WITH THIS IN MIND...WILL BE EXPANDING THE FREEZE WATCH TO INCLUDE ALL OF THE AREA. SEE WWA SECTION BELOW AND LATEST FREEZE WATCH STATEMENT FOR DETAILS. RIDGE STARTS TO BREAK DOWN/MOVE EAST LATE FRIDAY NIGHT THROUGH SATURDAY AS A FAIRLY VIGOROUS MID-LEVEL TROUGH PUSHES EAST INTO THE NORTHERN PLAINS/UPPER MISSISSIPPI RIVER REGION. AS STATED ABOVE...GFS AND NAM ARE DIFFERING AS TO THE STRENGTH OF THIS WAVE WITH THE GFS LOOKING A BIT STRONGER. THIS HAS A BEARING ON SURFACE COLD FRONT STRENGTH AND AMOUNT OF MOISTURE TRANSPORT NORTHWARD INTO THE AREA FOR THE PRODUCTION OF SHOWERS. WITH THIS IN MIND...WILL MOVE IN 20-30 PERCENT CHANCE OF SHOWERS TO ABOUT THE MISSISSIPPI RIVER THROUGH FRIDAY MORNING...INCREASING/EXPANDING TO 40 PERCENT CHANCE OF SHOWERS/ISOLATED THUNDER SATURDAY AFTERNOON ACROSS THE ENTIRE AREA. SHOWERS WILL LINGER INTO SATURDAY EVENING...THEN EXIT WITH THE COLD FRONTAL PASSAGE AFTER MIDNIGHT. AS FAR AS DAYTIME HIGH TEMPERATURES THURSDAY THROUGH SATURDAY...PLAN ON 50S THURSDAY AND FRIDAY...WARMING SOME INTO THE UPPER 50S TO LOWER 60S ON SATURDAY. .LONG TERM...SUNDAY THROUGH WEDNESDAY 318 PM CDT WED APR 4 2012 04.12Z GFS AND 04.00Z ECMWF IN OVERALL GOOD AGREEMENT THROUGH THE LONG TERM PERIOD WITH OVERALL DRY/COOLER CONDITIONS. BOTH MODELS SHOW THE AREA IN BREEZY DRYING WESTERLY FLOW DURING THE DAY SUNDAY IN THE WAKE OF THE COLD FRONT AND LOW PASSING THROUGH SOUTHERN ONTARIO CANADA. BREEZY/COOLER NORTHWEST FLOW INVADES THE AREA MONDAY THROUGH TUESDAY AS HIGH PRESSURE BUILDS SOUTHWARD INTO THE PLAINS/UPPER MISSISSIPPI RIVER REGION AND DEEP LOW PRESSURE ANCHORS OVER QUEBEC. SOME WARMING THEN EXPECTED ON WEDNESDAY AS THE AXIS OF THE SURFACE RIDGE SHIFTS EAST OF THE REGION AND HEIGHTS BUILD ALOFT. TEMPERATURE-WISE...LOOK FOR HIGHS IN THE MID-UPPER 50S SUNDAY...COOLING INTO THE UPPER 40S TO LOWER 50S MONDAY/TUESDAY...AND THEN BACK INTO THE MID-UPPER 50S WEDNESDAY. && .AVIATION...THIS AFTERNOON AND TONIGHT 1215 PM CDT WED APR 4 2012 VFR CONDITIONS THROUGHOUT FORECAST PERIOD WITH HIGH PRESSURE REMAINING IN CONTROL AND DRY LOW LEVEL EAST TO NORTHEAST FLOW. EASTWARD DRIFT OF UPPER LOW WILL KEEP EVEN HIGH CLOUDS MAINLY CONFINED SOUTH OF AVIATION CORRIDOR. && .FIRE WEATHER...THURSDAY THROUGH FRIDAY 318 PM CDT WED APR 4 2012 HUDSON BAY HIGH WILL PUMP A VERY DRY AIRMASS INTO THE REGION THURSDAY THROUGH FRIDAY. LOOK FOR AFTERNOON MINIMUM RH READINGS IN THE 20-25 PERCENT RANGE THURSDAY...MODERATING A FEW PERCENTAGE POINTS INTO THE MID 20S FRIDAY AFTERNOON. WINDS LOOK GENERALLY ON THE LIGHTER SIDE THURSDAY OUT OF THE EAST SOMEWHERE IN THE 5-12 MPH RANGE WITH SOME GUSTS AROUND 15 MPH. WINDS ARE THEN EXPECTED TO INCREASE OUT OF THE SOUTHEAST ON FRIDAY...ESPECIALLY WEST OF THE MISSISSIPPI RIVER FRIDAY AS THE HIGH BEGINS TO PUSH EAST INTO THE GREAT LAKES REGION. && .ARX WATCHES/WARNINGS/ADVISORIES... 318 PM CDT WED APR 4 2012 WI...FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR WIZ017-029-032>034-041>044-053>055-061. FREEZE WARNING FROM 2 AM TO 8 AM CDT THURSDAY FOR WIZ017-029-034- 042>044. MN...FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR MNZ079-086>088-094>096. IA...FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR IAZ008>011-018-019-029-030. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION...SHEA FIRE WEATHER...DAS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
233 PM CDT WED APR 4 2012 .SHORT TERM...TONIGHT AND THURSDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE CENTERED OVER NORTHERN MANITOBA WITH A RIDGE AXIS EXTENDING SOUTH OVER THE WESTERN GREAT LAKES. ONLY THIN CIRRUS IS PREVENTING A CLEAR DAY ACROSS THE FORECAST AREA THIS AFTERNOON. PRETTY QUIET UPSTREAM AS WELL...THANKS TO A BLOCKING MID-LEVEL RIDGE CENTERED OVER THE NORTHERN PLAINS AND CENTRAL CANADA. SOME COLDER AIR AND STRATO-CU ARE WORKING SE OVER EASTERN LAKE SUPERIOR...BUT SHOW NO SIGNS OF PUSHING WESTWARD DESPITE THE COLD ADVECTION. WITH A SEASONABLE BUT DRY AIRMASS IN PLACE...LOW TEMPS TONIGHT AND HUMIDITIES TOMORROW ARE THE MAIN FORECAST CONCERNS. TONIGHT...HUDSON BAY HIGH PRESSURE WILL BE BUILDING SOUTHEAST ACROSS NORTHERN ONTARIO AND NOSING SOUTHWARD ACROSS THE NORTHERN GREAT LAKES. THE AIRMASS IS NOT ALL THAT DIFFERENT COMPARED TO LAST NIGHT...THOUGH WE ARE STARTING OUT A TAD DRIER OVER CENTRAL AND NORTHEAST WISCONSIN COMPARED TO THIS TIME YESTERDAY AFTERNOON. 1000-850MB WIND SPEEDS WILL BE SLIGHTLY LOWER OVER N-C WISCONSIN THAN LAST NIGHT...WHICH SHOULD LEAD TO DECOUPLING. NORTHEAST WISCONSIN WILL CONTINUE TO HAVE NE WINDS FUNNELED DOWN THE BAY AND ONSHORE ALONG THE LAKE MICHIGAN SHORELINE. THIS SHOULD KEEP THE BL OVER NE WISCONSIN MIXY ENOUGH TO PREVENT TEMPS FROM FALLING TO FREEZE WARNING CRITERIA (28F AND BELOW). BUT DO EXPECT TEMPS TO BE A DEGREE OR TWO COOLER THAN LAST NIGHT DUE TO SUBTLE LOW LEVEL COLD ADVECTION AND SLIGHTLY DRIER AIR AT THE SURFACE. AS A RESULT...FORECAST MIN TEMPS SUGGEST THE INHERITED FREEZE WARNING HEADLINES DO NOT NEED TO BE EXPANDED FURTHER EAST THAN CURRENTLY COMPRISED...SO WILL LEAVE HEADLINES BE. LOWS RANGING FROM THE LOWER 20S NORTH TO LOWER 30S SOUTHEAST. THURSDAY...SURFACE RIDGE AXIS WILL REMAIN CENTERED ACROSS EASTERN WISCONSIN. THE AIRMASS CHANGES LITTLE TOMORROW...THOUGH IS SLIGHTLY COLDER DUE TO THE COLD ADVECTION FROM TONIGHTS PERIOD. NORTHEAST WINDS WILL CONTINUE TO KEEP NE WISCONSIN COOLER THAN CENTRAL WISCONSIN...AND HIGHS WILL RANGE FROM THE MID 50S WEST TO THE MIDDLE 40S EAST. HUMIDITY LEVELS WILL AGAIN FALL SLIGHTLY BELOW CRITICAL CRITERIA OVER NORTH-CENTRAL WISCONSIN...WITH COOLER AIR OFFSETTING LOWER DEWPOINTS IN THE AFTERNOON. .LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY...MAIN FCST CONCERNS ARE THE POTENTIAL FOR FROST/FREEZE CONDITIONS ON THURSDAY NIGHT...CONTINUED VERY DRY CONDITIONS CONTRIBUTING TO HIGH FIRE DANGER ON FRIDAY...AND PCPN CHANCES LATER SATURDAY INTO SATURDAY NIGHT. A HUDSON BAY HIGH WILL BRING VERY DRY CONDITIONS TO THE REGION THROUGH FRIDAY. CLEAR SKIES AND LIGHT WINDS WILL ALLOW TEMPS TO PLUMMET ON THURSDAY NIGHT...LEADING TO ANOTHER HARD FREEZE FOR AREAS WEST OF THE FOX VALLEY AND LAKESHORE. WILL KEEP THE CURRENT AREAL COVERAGE FOR THE FREEZE WATCH...BUT IT MAY NEED TO BE EXPANDED WITH SUBSEQUENT FCSTS... ESPECIALLY INTO SOUTHERN MARINETTE AND OCONTO COUNTIES. ON FRIDAY...MIXING THROUGH 850 MB SUPPORTS HIGH TEMPS IN THE MID TO UPPER 50S AWAY FROM THE LAKE. DEW POINTS SHOULD CRASH INTO THE TEENS AND LOWER 20S IN THE SANDY SOIL AREAS...LEADING TO ANOTHER DAY WITH RELATIVE HUMIDITY IN THE 15-25 PERCENT RANGE. THIS WILL CONTRIBUTE TO ANOTHER DAY OF HIGH FIRE DANGER. TEMPERATURES SHOULD CLIMB A BIT ON FRIDAY NIGHT AS THE HIGH SHIFTS EAST AND WINDS GRADUALLY VEER SOUTH. DID LOWER MIN TEMPS A LITTLE BIT TO ACCOUNT FOR LINGERING DRY AIR. A COLD FRONT AND ASSOCIATED UPPER TROF/LOW WILL APPROACH LATER ON SATURDAY...THEN MOVE THROUGH THE FORECAST AREA SATURDAY NIGHT... SO HAVE MAINTAINED THE CHC POPS DURING THIS PERIOD. INSTABILITY PARAMETERS ARE UNIMPRESSIVE...BUT WITH 700-500 MB LAPSE RATES IN THE 6-7 C/KM RANGE...DECIDED TO KEEP THE MENTION OF ISOLD TSTMS. ORIGINALLY THOUGHT THAT THE GFS WAS TOO ROBUST AND TOO FAR SOUTH WITH THE UPPER LOW ARRIVING FROM THE NORTHERN PLAINS LATE IN THE WEEKEND...BUT THE 12Z ECMWF HAS STRONGLY TRENDED THAT DIRECTION... AND BRINGS A SLOWLY WEAKENING UPPER LOW THROUGH WI SUNDAY AND SUNDAY NIGHT. THIS GOES AGAINST THE TRENDS OF MOST MODELS AND ENSEMBLES...SO WILL KEEP A DRY FCST INTACT FOR NOW. WILL NEED TO KEEP AN EYE ON THIS FOR SUBSEQUENT FCSTS. NORTHWEST CANADIAN HIGH PRESSURE WILL BRING DRY WEATHER TO THE REGION TUESDAY INTO WEDNESDAY. TEMPERATURES WILL CONTINUE TO AVERAGE NEAR OR A BIT ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION...CANADIAN HIGH PRESSURE WILL REMAIN ACROSS THE REGION THROUGH FRIDAY...LEADING TO VFR CONDITIONS AT THE TAF SITES. THERE IS A VERY SMALL CHANCE THAT HIGH END MVFR CIGS REACH FAR NE WISCONSIN LATE TONIGHT INTO THURSDAY MORNING. WILL MENTION POSSIBILITY TO LATER SHIFTS. MPC && .MARINE...A TIGHTENING PRESSURE GRADIENT WILL LEAD TO THE STRENGTHENING OF NORTHEAST WINDS OVER NORTHERN LAKE MICHIGAN THIS EVENING. WITH 25-30 KTS AT 950-925MB...INSTABILITY IS MARGINAL FOR SMALL CRAFT WIND AND WAVES DEVELOPING. WAVES WILL BE INCREASING INTO THE HIGHER END OF THE 2-4 FT RANGE OVERNIGHT...BUT LOOK TO FALL SLIGHTLY SHORT OF SMALL CRAFT CRITERIA. && .GRB WATCHES/WARNINGS/ADVISORIES... FREEZE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY MORNING FOR WIZ005-010>013-018>021-030-031-035>037-045. FREEZE WARNING FROM 2 AM TO 8 AM CDT THURSDAY FOR WIZ005-010>013- 018>021-030-031-035>037-045. && $$ MPC/KIECKBUSCH