Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 09/29/12


AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1037 AM MDT THU SEP 27 2012 .UPDATE... && .SHORT TERM...UPPER LOW ESSSENTIALLY CUTOFF FROM THE MEAN FLOW ALOFT CONTINUES TO TREK VERY SLOWLY EASTWARD ACROSS NORTHERN COLORADO AT THIS HOUR. IR AND WATER VAPOR SAT IMAGERY INDICATE THE CENTER OF THIS CYCLONE OVER KREMMLING IN WESTERN GRAND COUNTY IN N/CNTRL COLORADO. RUC HT TENDENCY FIELDS INDICATED A SLIGHT DEEPENING IN THIS LOW THIS MORNING...HOWEVER MODELS FORECAST A GRADUAL INCREASE IN HEIGHTS AS THE 500MB LOW PASSES OVER NORTHEAST COLORADO. MEANWHILE CIRCULATION AROUND THIS LOW CONTINUES TO PILE LOW/MID- LEVEL CLOUDS UP THE WEST SIDE OF CONTINENTAL DIVIDE WHERE SCATTERED LIGHT TO MODERATE SHOWERS HAVE BEEN OBSERVED. SNOW LEVELS REMAIN HIGH THIS MORNING WITH THIS MORNING/S FREEZE LEVEL UP AROUND 12,300 FT MSL. AS THE COLD AIR POOL ASSOCIATED WITH LOW PASSES OVERHEAD...COULD SEE THE SNOW LEVEL LEVELING TO AROUND 10500-11000 FT MSL OVER THE NEXT SEVERAL HOURS. NEXT ON PLAINS...LOW/MID-LEVEL CLOUDS WRAPPING NORTHWESTWARD BACK INTO THE UPPER LOW AND THE SFC LOW IN SRN WELD COUNTY GENERATING ISOLATED TO SCATTERED LIGHT RAIN SHOWERS ACROSS THE NORTHEAST CORNER OF THE STATE FOR MOST OF THE MORNING. LIGHT DOWNSLOPE FLOW OFF THE FRONT RANGE RESULTED IN SOME CLEARING OVER SOUTHERN PORTIONS OFF THE I-25 CORRIDOR EARLIER THIS MORNING. ALTHOUGH IN THE PAST HOUR WITH THE LITTLE SOLAR HEATING WE SAW AND NOW WITH THE COOLING ALOFT...CLOUDS HAVE BEGUN TO FILL IN OVER THE ENTIRE AREA. FURTHERMORE...A JETLET CURRENTLY ROUNDING THE BOTTOM OF THE UPPER LOW WAS ALREADY HELPING TO ENHANCE CONVECTION/COOL CLOUD TOPS OVER EL PASO...DOUGLAS AND LINCOLN COUNTIES. BASED ON CURRENT TRENDS...SHOULD SEE THIS ENHANCEMENT SPREADING NORTHWARD OVER EASTERN SECTIONS OF THE CWFA. AS IT APPEARS NOW...THE AREA MOST LIKELY TO SEE THUNDERSTORMS TODAY...ROUGHLY AFTER 18Z WILL BE EAST OF A BRIGGSDALE/WELD COUNTY TO KIOWA/ELBERT COUNTY LINE WHERE CAPES ARE PROGGED TO BE IN THE 600-1200 J/KG RANGE LATER TODAY. WEST OF THE LINE...CAN NOT RULE OUT A STRAY T-STORM BUT WITH LOW LEVELS EXPECTED TO BEGIN DRYING LATER THIS AFTERNOON WITH DOWNSLOPE FLOW DEVELOPING ON THE BACK SIDE OF THE UPPER LOW...THE CHANCE FOR T-STORMS SHOULD DWINDLE TO NEAR ZERO TOWARDS 00Z. AS FOR RAIN AMOUNTS...QPF FIELDS INDICATING 0.20 TO 0.45 INCH TOTALS BY 03Z THIS EVENING ON THE PLAINS WITH THE HEAVIER AMOUNTS ASSOCIATED WITH THE T-STORM ACTIVITY. FOR THE HIGH COUNTRY...PARTICULARLY UP ALONG THE CONTINENTAL DIVIDE ABOVE 11000 FT AND GENERALLY NORTH OF I-70...COULD SEE ANOTHER FEW INCHES OF SNOW BEFORE WINDING DOWN THIS EVENING. OTHERWISE TEMPERATURE FORECAST APPEARS TO BE ON TRACK. HOWEVER... OUR WIND FCST WILL REMAIN A WORK IN PROGRESS THROUGHOUT THE DAY WITH THE SFC AND UPPER LOWS PULLING AWAY. .AVIATION...THE LOW AND MID-LEVEL CLOUD DECK MOVING SOUTHWARD DOWN ALONG THE FRONT RANGE FOOTHILLS IS EXPECTED TO SPREAD OVER THE DENVER AREA IN THE NEXT HOUR OR SO. ALREADY SEEING CEILINGS AROUND 500 FT AGL AT BJC. PROBABLY IN THE NEXT HOUR COULD SEE BROKEN CIGS AS LOW AS 1000-1500 FT AGL AT DENVER/S DIA AND APA AIRPORTS. PATCHY FOG AROUND BJC MAY BRIEFLY LOWER VSBYS TO 3-5 MILES NEXT FEW HOURS. AFTER 18Z...THE CHANCE FOR RAIN SHOWERS WILL INCREASE AS MOIST UPSLOPE FLOW DEVELOPS ON THE BACKSIDE OF THE PASSING UPPER LOW. THE DENVER AREA MAY ALSO SEE A BRIEF T-STORM THIS AFTERNOON...BUT THEIR INTENSITY SHOULD REMAIN ON THE WEAK SIDE. AFTER 23Z OR 00Z THIS EVENING..THE DENVER AREA SHOULD BEGIN TO SEE GRADUAL IMPROVEMENT AS DRIER AIR MOVES DOWN OFF THE FRONT RANGE. HOWEVER LATE TONIGHT WITH CLEARING SKIES...PORTIONS OFF THE DENVER AREA...INCLUDING DIA MAY SEE PATCHY FOG FORMING TOWARDS DAWN. && .HYDROLOGY...SHOWERS AND ISOLATED THUNDERSTORMS REMAIN IN THE FORECAST FOR THE FRONT RANGE BURN SCARS TODAY. HOWEVER RAIN AMOUNTS ARE EXPECTED TO REMAIN LIGHT...GENERALLY UNDER A QUARTER INCH. THEREFORE FLOODING IS NOT ANTICIPATED. && .PREV DISCUSSION... /ISSUED 405 AM MDT THU SEP 27 2012/ SHORT TERM...UPPER TROUGH IS ROTATING NORTHEASTWARD WITH A LOW CENTER NEAR HAYDEN. THIS IS BRINGING SOME DRYING INTO OUR AREA FROM THE SOUTH EARLY THIS MORNING...AND WHAT IS LEFT OF THE SHOWER ACTIVITY IS NEARING THE EASTERN AND NORTHERN BORDER. CLOUDS ARE STARTING TO FILL IN AGAIN FROM THE WEST THOUGH AS MOISTURE WRAPS AROUND THE LOW. BETWEEN AN EASTWARD PROGRESSION OF THE LOW WITH THE DRY SLOT FILLING AND THE DAYTIME HEATING...WE SHOULD HAVE PRETTY GOOD COVERAGE OF SHOWERS AGAIN. IF THERE WERE MORE SUNSHINE WE COULD GENERATE BETTER INSTABILITY...BUT THE COMBINATION OF SLIGHT DRYING AND EARLY CLOUD COVER SHOULD KEEP A LID ON THINGS. MODEL SOUNDINGS SHOW CAPES UP TO AROUND 1200 J/KG AT NOON...BUT THEN LESS LATER ON DUE TO SOME LOW LEVEL DRYING/MIXING. IN ANY EVENT...SHOULD BE ENOUGH CAPE FOR THUNDERSTORMS THIS AFTERNOON. OVERALL HEAVY RAIN SHOULD BE A BIT LESS OF A THREAT WITH STORM MOTIONS AT LEAST 10 KNOTS...THOUGH TOWARD THE NORTHERN BORDER THE MOTIONS COULD BE SLOWER AS THE LOW MOVES BY. THERE WILL STILL BE HEAVY RAIN IN THE STRONGER THUNDERSTORM CORES...BUT ODDS OF REALLY SLOW MOVING STORMS LOOK LOWER TODAY. SO FEW CHANGES WITH THIS PACKAGE...MAINLY TO DRY THINGS OUT A LITTLE THIS MORNING AND THEN ADD PATCHY FOG LATE TONIGHT. LONG TERM...MODELS HAVE WEAK UPPER RIDGING MOVING INTO COLORADO FRIDAY AND SATURDAY. THE FLOW ALOFT IS VERY WEAK AND MAINLY WESTERLY FRIDAY INTO SATURDAY EVENING. THE SYNOPTIC SCALE ENERGY IS PROGGED TO BE NEUTRAL OR WEAK DOWNWARD IN NATURE FRIDAY THROUGH SATURDAY NIGHT. THE BOUNDARY LAYER FLOW WILL BE DICTATED BY A WEAK LOW LEVEL PRESSURE GRADIENT THROUGH THE FOUR PERIODS...SO THE NORMAL DIURNAL WIND PATTERNS ARE A GOOD BET. FOR MOISTURE...THERE IS SOME AROUND ON FRIDAY INTO FRIDAY EVENING...ESPECIALLY ON THE NAM. THE GFS AND ECMWF ARE DRIER. FRIDAY NIGHT DRIES OUT SOMEWHAT. SATURDAY AND SATURDAY NIGHT ARE FAIRLY DRY...BUT THERE IS STILL SOME MID AND UPPER LEVEL MOISTURE AROUND. PRECIPITABLE WATER VALUES ARE GENERALLY IN THE 0.50 TO 0.65 INCH RANGE ALL FOUR PERIODS. THERE IS SOME CAPE PROGGED FOR THE CWA FRIDAY AND SATURDAY AFTERNOONS. VALUES ARE UNDER 800 J/KG...WITH MORE NOTED OVER THE PLAINS...BUT STILL SOME IN THE MOUNTAINS. THE QPF FIELDS SHOW LIMITED MEASURABLE PRECIPITATION MAINLY OVER THE MOUNTAINS AND FOOTHILLS BOTH LATE DAY FRIDAY AND LATE DAY SATURDAY. FOR POPS...20-30%S LATE DAY FRIDAY AND 10-20%S LATE DAY SATURDAY. FOR TEMPERATURES...FRIDAY`S HIGHS ARE 2.0-3.5 C WARMER THAN TODAY`S. SATURDAY`S HIGHS WARM ANOTHER 1.0-2.5 C OVER FRIDAY`S. FOR THE LATER DAYS...SUNDAY THROUGH WEDNESDAY...MODELS HAVE AN UPPER RIDGE TO OUR WEST INTO WEDNESDAY. A WEAK UPPER TROUGH IS HINTED AT ON WEDNESDAY...BUT IT IS INSIGNIFICANT. THE FLOW ALOFT WILL BE WEAK AND NORTHERLY MONDAY AND TUESDAY...THEN NORTHWESTERLY AND WEAK TUESDAY AND WEDNESDAY. MOISTURE IS POOR. TEMPERATURES ARE ABOVE SEASONAL NORMALS. AVIATION...VFR CONDITIONS THIS MORNING. SCATTERED SHOWERS AND THUNDERSTORMS MAY CAUSE LOCALIZED MVFR CONDITIONS THIS AFTERNOON AND THERE WILL LIKELY BE A PERIOD WHEN INSTRUMENT APPROACHES TO KDEN ARE NEEDED. CONVECTION ENDING THIS EVENING WITH A SLIGHT CHANCE OF IFR CONDITIONS IN FOG LATE TONIGHT AND EARLY FRIDAY. HYDROLOGY...LOW THREAT OF FLOODING TODAY AS SOME OF THE STORMS WILL PRODUCE HEAVY RAIN. IN GENERAL STORMS WILL BE MOVING AT LEAST 10 MPH WHICH WILL LIMIT THE FLOOD THREAT. HEAVIEST STORMS COULD PRODUCE AN INCH OF RAIN IN AN HOUR...WITH UP TO 1.5 INCHES ON THE PLAINS...BUT THESE RAINS WILL BE VERY LOCALIZED IF THEY OCCUR. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BAKER/GIMMESTAD LONG TERM....RJK AVIATION...BAKER/GIMMESTAD
AREA FORECAST DISCUSSION
NWS NEW YORK NY
445 PM EDT THU SEP 27 2012 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN JUST TO THE SOUTH THROUGH TONIGHT. PRESSURE WILL MOVE SLOWLY EAST ALONG THE FRONT FROM THE OHIO VALLEY TO SOUTHEAST PENNSYLVANIA BY FRIDAY MORNING...AND THEN CROSS THE REGION FRIDAY AFTERNOON AND NIGHT. THE LOW WILL THEN MOVE AWAY ON SATURDAY. ANOTHER WEAK LOW WILL PASS TO THE NORTHEAST SUNDAY NIGHT INTO MONDAY. YET ANOTHER LOW WILL PASS TO THE SOUTHEAST TUESDAY INTO TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE BUILDING IN FOR WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM COULD AFFECT THE REGION AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... SCT-BKN STRATOCU DEVELOPMENT THROUGH THIS AFTERNOON VIA HEATING/MIXING. UPSTREAM MID CLOUDS ARE BEGINNING TO WORK IN AS WELL FROM NYC WEST. HIGH TEMPS IN THE MID 70S FOR MOST AREAS ON TRACK...WITH LOCALLY UPPER 70S IN NYC/NJ METRO. AFTERNOON SEA BREEZE WILL KNOCK TEMPS BACK INTO THE LOWER 70S THIS AFTERNOON ALONG COASTAL AREAS. OVERRUNNING RAINS AHEAD OF THE WEAK SFC LOW WERE ENTERING SW PA AS OF 18Z. LATEST HRRR INDICATES THIS RAIN SHOULD ENTER WRN SECTIONS DURING THE LATE EVENING...THEN SPREAD EWD INTO THE REST OF THE CWA AFTER MIDNIGHT. RAIN COULD BECOME HEAVY AT TIMES FROM NYC NORTH/WEST TOWARD DAYBREAK. LOWS A BLEND OF MAV/MET GUIDANCE...WITH 60-65 NYC METRO AND LONG ISLAND...AND 55-60 ELSEWHERE. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... NWP GUIDANCE SUGGESTS HEAVIEST RAIN VIA BEST ISENTROPIC/OROGRAPHIC LIFT AND FRONTOGENETIC FORCING WILL INITIALLY BE FOCUSED MORE JUST TO THE NORTH/WEST OF THE CWA INTO FRI MORNING...BUT EVEN SO NYC METRO AND THE LOWER HUDSON VALLEY SHOULD RECEIVE ABOUT AN INCH OF RAIN THROUGH MIDDAY FRI. AS THE WEAK LOW MOVES ACROSS FRI AFTERNOON...COMBO OF GOOD MOISTURE TRANSPORT...ISENTROPIC LIFT AND INSTABILITY JUST TO ITS EAST WITH MUCAPE INCREASING TO 500-1000 J/KG SHOULD BE ENOUGH TO SUPPORT MODERATE TO LOCALLY HEAVY RAIN AND TSTMS. MOST MODELS ARE UNDERPLAYING THIS...EXCEPT FOR THE 12Z RGEM WHICH IS A VERY WET OUTLIER WITH UP TO 2 INCHES TOTAL QPF ACROSS SOUTHERN CT FRI AFTERNOON. NYC METRO AND COASTAL SECTIONS MAY GET INTO THE WARM SECTOR...WHERE INSTABILITY WILL BE SFC-BASED AND WHERE A FEW GUSTY TSTMS ARE POSSIBLE. THIS COMBO OF GOOD MOISTURE TRANSPORT...LIFT AND INSTABILITY SHOULD LINGER ACROSS LONG ISLAND AND SOUTHERN CT INTO THE EVENING...THEN WANE AFTER MIDNIGHT. A SECOND ROUND OF SHOWERS/TSTMS MAY BE POSSIBLE FOR LONG ISLAND AND SOUTHERN CT LATE FRI NIGHT AS A STRONG MID LEVEL VORT MAX AND POSSIBLE INDUCED SFC WAVE SWEEP ACROSS OR JUST TO THE SE. MODELS DISAGREE ON TIMING/PLACEMENT...SO HAVE JUST CONTINUED A GENERIC CHANCE POP DURING THAT TIME. THERE IS A HIGH RISK OF RIP CURRENTS AT THE OCEAN BEACHES WEDNESDAY. && .LONG TERM /SATURDAY THROUGH THURSDAY/... SOMEWHAT UNSETTLED..ALBEIT LIGHT PRECIPITATION IN THE LONG TERM AS CUT OFF UPPER LEVEL LOW AND NEARLY STATIONARY COLD FRONT WELL OFF THE EAST COAST ARE THE MAIN PLAYERS TO START OFF THE PERIOD. SURFACE LOW PRESSURE ALONG THE STALLED FRONTAL BOUNDARY PUSHES AWAY FROM THE AREA AS THE UPPER LEVEL LOW SITUATED BETWEEN THE HUDSON BAY AND THE GREAT LAKES MOVES SOUTHWEST TOWARD THE GREAT LAKES ON SATURDAY. WITH THE UPPER LOW IN THE VICINITY AND COLD POOL ALOFT...THERE WILL BE SOME INSTABILITY SHOWERS ACROSS THE AREA...WITH THE BEST CHANCES NORTH AND WEST OF THE NEW YORK METRO AREA. A PIECE OF ENERGY FROM THE UPPER LEVEL LOW THEN SWINGS ACROSS THE EASTERN GREAT LAKES AND TRACKS TO THE NORTHEAST SUNDAY INTO MONDAY. THERE IS A GOOD DEAL OF UNCERTAINTY WITH THE TRACK OF THIS LOW. ALL MODELS TRACK THIS LOW TO THE NORTH AND EAST OF THE AREA...BUT THE ECMWF TRACKS THE LOW THROUGH CENTRAL NY...WHILE THE GFS TRACKS IT ACROSS THE EASTERN GREAT LAKES...AND THE GEM IS CLOSER TO THE ECMWF...BUT WEAKENS IT AS IT GETS ABSORBED INTO A COASTAL LOW. THE ECMWF ALSO HAS THIS COASTAL LOW...BUT IT IS FARTHER OFFSHORE...MORE ALIGNED WITH THE COLD FRONT...AND WEAKER. SO WENT WITH CHANCE POPS DUE TO UNCERTAINTY. HIGH PRESSURE BUILDS IN FOR MONDAY NIGHT. LOW PRESSURE FORMS ALONG THE FRONTAL BOUNDARY OVER THE SOUTHEAST U.S. AND TRACKS NORTHEAST MONDAY. ECMWF AND GEM TRACKS THE LOW SOUTH AND EAST OF THE CWA...WITH A SOLID HALF INCH OF QPF...WHILE THE GFS IS MORE SUPPRESSED WITH HIGH PRESSURE OVER THE REGION FOR TUESDAY. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT AND WEDNESDAY...WITH POSSIBLY ANOTHER SYSTEM POISED TO AFFECT THE REGION AT THE END OF THE WEEK. && .AVIATION /21Z THURSDAY THROUGH TUESDAY/... A COLD FRONT WILL REMAIN JUST TO THE SOUTH TODAY. A WAVE OF LOW PRESSURE...ON THE FRONT...APPROACHES FROM THE WEST TONIGHT. AS SEA BREEZE WINDS WEAKEN THIS EVENING WINDS WILL SHIFT TO THE E/ESE AND INCREASE IN SPEED LATE TONIGHT INTO FRIDAY MORNING. MODERATE CONFIDENCE IN 15-20 KT ESE WINDS LATE TONIGHT INTO FRIDAY MORNING. VFR THROUGH EARLY THIS EVENING...THEN CEILINGS GRADUALLY LOWER TO MVFR LATE THIS EVENING. RAIN BECOMES INCREASINGLY LIKELY AFTER MIDNIGHT TONIGHT. MODERATE CONFIDENCE IN IFR CONDITIONS IN WIND AND RAIN AHEAD OF LOW PRESSURE TOWARDS DAYBREAK AND THROUGH FRIDAY MORNING. ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS METRO AND EASTERN TERMINALS...BUT TOO LOW PROBABILITY TO MENTION EXPLICITLY IN TAFS. 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: HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KJFK FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KLGA FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KTEB FCSTER COMMENTS: SEA BREEZE MAY MOVE THROUGH AFTER 22Z...OTHERWISE WINDS REMAIN LIGHT AND VARIABLE. HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KHPN FCSTER COMMENTS: WINDS LIKELY REMAIN LIGHT AND VARIABLE...LOW CONFIDENCE IN SEA BREEZE MOVING THROUGH. HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KISP FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. OUTLOOK FOR 18Z FRI-TUE... .FRI...HIGH CONFIDENCE OF MVFR OR LOWER CONDITIONS IN RAIN. .FRI NIGHT-TUE...GENERALLY VFR BUT MVFR OR LOWER CONDITIONS POSSIBLE AT TIMES IN SHOWERS. LOW CONFIDENCE ON DETAILS. && .MARINE... SCA NOW IN EFFECT FOR ALL WATERS...BEGINNING ON THE OCEAN LATE TONIGHT AND ON THE HARBOR/SOUND/BAYS BY FRI MORNING. EASTERLY FLOW LOOKS TO INCREASE TO 15-20 WITH GUSTS UP TO 25 KT DURING THIS TIME. OCEAN SEAS SHOULD MAX OUT AT EITHER 6-7 FT ON FRI...ABOUT 1 FT ABOVE 12Z WAVEWATCH. SCA CONDS SHOULD LINGER ON THE ERN OCEAN WATERS UNTIL ABOUT MIDNIGHT FRI NIGHT...THEN QUIET CONDITIONS ARE EXPECTED. && .HYDROLOGY... UP TO 2 INCHES OF RAINFALL POSSIBLE LATE TONIGHT THROUGH FRI NIGHT. THE HEAVIEST RAIN WILL FALL MOSTLY NW OF THE LOW CENTER INITIALLY LATE TONIGHT INTO FRI MORNING...FROM NYC METRO AND POINTS NORTH/WEST...BUT THEN HEAVY RAIN FOCUS SHOULD SHIFT TO LONG ISLAND AND SOUTHERN CT IN THE AFTERNOON JUST AHEAD OF THE LOW AS IT MOVES ACROSS. MAIN CONCERN IS FOR MINOR FLOODING. ISOLD FLASH FLOODING COULD OCCUR WITH HEAVIEST TSTMS FRI AFTERNOON AND EARLY EVENING ACROSS LONG ISLAND AND SOUTHERN CT...BUT THIS THREAT APPEARS TOO LOW/ISOLD TO WARRANT A WATCH. A STORM TOTAL GRAPHIC HAS BEEN POSTED TO THE WEB. && .TIDES/COASTAL FLOODING... COMBO OF HIGH ASTRONOMICAL HIGH TIDES WITH THE UPCOMING FULL MOON PLUS ABOUT 1 TO 1.5 FT OF SURGE AHEAD OF THE LOW APPROACHING TONIGHT AND MOVING ACROSS ON FRI COULD LEAD TO ISOLATED MINOR COASTAL FLOODING AT THE TIMES OF HIGH TIDE FRI NIGHT IN THE MOST VULNERABLE LOCATIONS ALONG THE SOUTH SHORE BACK BAYS OF WRN LONG ISLAND...AND ALONG WRN LONG ISLAND SOUND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO NOON EDT FRIDAY FOR ANZ335- 338-345. SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT FRIDAY FOR ANZ330- 340. SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM EDT FRIDAY FOR ANZ350- 353-355. && $$ SYNOPSIS... NEAR TERM...GOODMAN SHORT TERM...GOODMAN LONG TERM... AVIATION...MET MARINE...GOODMAN HYDROLOGY...GOODMAN TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
358 PM EDT THU SEP 27 2012 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN JUST TO THE SOUTH THROUGH TONIGHT. PRESSURE WILL MOVE SLOWLY EAST ALONG THE FRONT FROM THE OHIO VALLEY TO SOUTHEAST PENNSYLVANIA BY FRIDAY MORNING...AND THEN CROSS THE REGION FRIDAY AFTERNOON AND NIGHT. THE LOW WILL THEN MOVE AWAY ON SATURDAY. ANOTHER WEAK LOW WILL PASS TO THE NORTHEAST SUNDAY NIGHT INTO MONDAY. YET ANOTHER LOW WILL PASS TO THE SOUTHEAST TUESDAY INTO TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE BUILDING IN FOR WEDNESDAY. ANOTHER LOW PRESSURE SYSTEM COULD AFFECT THE REGION AT THE END OF THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... SCT-BKN STRATOCU DEVELOPMENT THROUGH THIS AFTERNOON VIA HEATING/MIXING. UPSTREAM MID CLOUDS ARE BEGINNING TO WORK IN AS WELL FROM NYC WEST. HIGH TEMPS IN THE MID 70S FOR MOST AREAS ON TRACK...WITH LOCALLY UPPER 70S IN NYC/NJ METRO. AFTERNOON SEA BREEZE WILL KNOCK TEMPS BACK INTO THE LOWER 70S THIS AFTERNOON ALONG COASTAL AREAS. OVERRUNNING RAINS AHEAD OF THE WEAK SFC LOW WERE ENTERING SW PA AS OF 18Z. LATEST HRRR INDICATES THIS RAIN SHOULD ENTER WRN SECTIONS DURING THE LATE EVENING...THEN SPREAD EWD INTO THE REST OF THE CWA AFTER MIDNIGHT. RAIN COULD BECOME HEAVY AT TIMES FROM NYC NORTH/WEST TOWARD DAYBREAK. LOWS A BLEND OF MAV/MET GUIDANCE...WITH 60-65 NYC METRO AND LONG ISLAND...AND 55-60 ELSEWHERE. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... NWP GUIDANCE SUGGESTS HEAVIEST RAIN VIA BEST ISENTROPIC/OROGRAPHIC LIFT AND FRONTOGENETIC FORCING WILL INITIALLY BE FOCUSED MORE JUST TO THE NORTH/WEST OF THE CWA INTO FRI MORNING...BUT EVEN SO NYC METRO AND THE LOWER HUDSON VALLEY SHOULD RECEIVE ABOUT AN INCH OF RAIN THROUGH MIDDAY FRI. AS THE WEAK LOW MOVES ACROSS FRI AFTERNOON...COMBO OF GOOD MOISTURE TRANSPORT...ISENTROPIC LIFT AND INSTABILITY JUST TO ITS EAST WITH MUCAPE INCREASING TO 500-1000 J/KG SHOULD BE ENOUGH TO SUPPORT MODERATE TO LOCALLY HEAVY RAIN AND TSTMS. MOST MODELS ARE UNDERPLAYING THIS...EXCEPT FOR THE 12Z RGEM WHICH IS A VERY WET OUTLIER WITH UP TO 2 INCHES TOTAL QPF ACROSS SOUTHERN CT FRI AFTERNOON. NYC METRO AND COASTAL SECTIONS MAY GET INTO THE WARM SECTOR...WHERE INSTABILITY WILL BE SFC-BASED AND WHERE A FEW GUSTY TSTMS ARE POSSIBLE. THIS COMBO OF GOOD MOISTURE TRANSPORT...LIFT AND INSTABILITY SHOULD LINGER ACROSS LONG ISLAND AND SOUTHERN CT INTO THE EVENING...THEN WANE AFTER MIDNIGHT. A SECOND ROUND OF SHOWERS/TSTMS MAY BE POSSIBLE FOR LONG ISLAND AND SOUTHERN CT LATE FRI NIGHT AS A STRONG MID LEVEL VORT MAX AND POSSIBLE INDUCED SFC WAVE SWEEP ACROSS OR JUST TO THE SE. MODELS DISAGREE ON TIMING/PLACEMENT...SO HAVE JUST CONTINUED A GENERIC CHANCE POP DURING THAT TIME. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... SOMEWHAT UNSETTLED..ALBEIT LIGHT PRECIPITATION IN THE LONG TERM AS CUT OFF UPPER LEVEL LOW AND NEARLY STATIONARY COLD FRONT WELL OFF THE EAST COAST ARE THE MAIN PLAYERS TO START OFF THE PERIOD. SURFACE LOW PRESSURE ALONG THE STALLED FRONTAL BOUNDARY PUSHES AWAY FROM THE AREA AS THE UPPER LEVEL LOW SITUATED BETWEEN THE HUDSON BAY AND THE GREAT LAKES MOVES SOUTHWEST TOWARD THE GREAT LAKES ON SATURDAY. WITH THE UPPER LOW IN THE VICINITY AND COLD POOL ALOFT...THERE WILL BE SOME INSTABILITY SHOWERS ACROSS THE AREA...WITH THE BEST CHANCES NORTH AND WEST OF THE NEW YORK METRO AREA. A PIECE OF ENERGY FROM THE UPPER LEVEL LOW THEN SWINGS ACROSS THE EASTERN GREAT LAKES AND TRACKS TO THE NORTHEAST SUNDAY INTO MONDAY. THERE IS A GOOD DEAL OF UNCERTAINTY WITH THE TRACK OF THIS LOW. ALL MODELS TRACK THIS LOW TO THE NORTH AND EAST OF THE AREA...BUT THE ECMWF TRACKS THE LOW THROUGH CENTRAL NY...WHILE THE GFS TRACKS IT ACROSS THE EASTERN GREAT LAKES...AND THE GEM IS CLOSER TO THE ECMWF...BUT WEAKENS IT AS IT GETS ABSORBED INTO A COASTAL LOW. THE ECMWF ALSO HAS THIS COASTAL LOW...BUT IT IS FARTHER OFFSHORE...MORE ALIGNED WITH THE COLD FRONT...AND WEAKER. SO WENT WITH CHANCE POPS DUE TO UNCERTAINTY. HIGH PRESSURE BUILDS IN FOR MONDAY NIGHT. LOW PRESSURE FORMS ALONG THE FRONTAL BOUNDARY OVER THE SOUTHEAST U.S. AND TRACKS NORTHEAST MONDAY. ECMWF AND GEM TRACKS THE LOW SOUTH AND EAST OF THE CWA...WITH A SOLID HALF INCH OF QPF...WHILE THE GFS IS MORE SUPPRESSED WITH HIGH PRESSURE OVER THE REGION FOR TUESDAY. HIGH PRESSURE BUILDS IN FOR TUESDAY NIGHT AND WEDNESDAY...WITH POSSIBLY ANOTHER SYSTEM POISED TO AFFECT THE REGION AT THE END OF THE WEEK. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... A COLD FRONT WILL REMAIN JUST TO THE SOUTH TODAY. HIGH PRESSURE WILL SLIDE ACROSS NEW ENGLAND THROUGH FRIDAY...WHILE LOW PRESSURE APPROACHES FROM THE WEST TONIGHT. WIND DIRECTION CONTINUES TO BE MAIN CHALLENGE THROUGH THIS AFTERNOON. LIGHT NE TO VARIABLE WINDS WILL GRADUALLY VEER TO THE EAST THROUGH THIS EVENING. BEFORE THEN...SEA BREEZE DEVELOPMENT...EVIDENT ON TERMINAL RADAR...WILL BRING A WIND SHIFT TO THE S/SE THIS AFTERNOON ACROSS MOST OF THE COASTAL TERMINALS. HIGH CONFIDENCE IN WINDS DIRECTION BECOMING E/ESE THIS EVENING AND INCREASING IN SPEED LATE TONIGHT INTO FRIDAY MORNING. MODERATE CONFIDENCE IN 15-20 KT ESE WINDS LATE TONIGHT INTO FRIDAY MORNING. GENERALLY VFR CONDITIONS THROUGH THE REMAINDER OF THE AFTERNOON...WITH SCATTERED TO BROKEN CU ALONG WITH MID/HIGH CLOUDS REMAIN IN THE FORECAST. CIGS ACROSS NW TERMINALS MAY OCCASIONALLY BE BROKEN AROUND 3000FT THROUGH AROUND 22Z. CEILINGS GRADUALLY LOWER TO MVFR LATE THIS EVENING WITH ONSHORE FLOW. RAIN BECOMES INCREASINGLY LIKELY AFTER MIDNIGHT TONIGHT. MODERATE CONFIDENCE IN IFR CONDITIONS IN WIND AND RAIN AHEAD OF LOW PRESSURE TOWARDS DAYBREAK AND THROUGH FRIDAY MORNING. ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS METRO AND EASTERN TERMINALS...BUT TOO LOW PROBABILITY TO MENTION EXPLICITLY IN TAFS. 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: AMENDMENTS POSSIBLE FOR SEA BREEZE TIMING...AROUND 19Z. HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KJFK FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KLGA FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEA BREEZE TIMING...BETWEEN 20Z AND 21Z. HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KTEB FCSTER COMMENTS: SEA BREEZE POSSIBLE BETWEEN 20Z AND 21Z. HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KHPN FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEA BREEZE TIMING...AROUND 19Z. HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. KISP FCSTER COMMENTS: AMENDMENTS POSSIBLE FOR SEA BREEZE TIMING...BETWEEN 19Z AND 20Z. HIGH CONFIDENCE IN MVFR CONDITIONS DEVELOPING AFTER 06Z...AND MODERATE CONFIDENCE IN IFR CONDS IN WIND AND RAIN BY AROUND 12Z. ESE WINDS OF OUTLOOK FOR 12Z FRI-TUE... .FRI...HIGH CONFIDENCE OF MVFR OR LOWER CONDITIONS IN RAIN. .FRI NIGHT-TUE...GENERALLY VFR BUT MVFR OR LOWER CONDITIONS POSSIBLE AT TIMES IN SHOWERS. LOW CONFIDENCE ON DETAILS. && .MARINE... SCA NOW IN EFFECT FOR ALL WATERS...BEGINNING ON THE OCEAN LATE TONIGHT AND ON THE HARBOR/SOUND/BAYS BY FRI MORNING. EASTERLY FLOW LOOKS TO INCREASE TO 15-20 WITH GUSTS UP TO 25 KT DURING THIS TIME. OCEAN SEAS SHOULD MAX OUT AT EITHER 6-7 FT ON FRI...ABOUT 1 FT ABOVE 12Z WAVEWATCH. SCA CONDS SHOULD LINGER ON THE ERN OCEAN WATERS UNTIL ABOUT MIDNIGHT FRI NIGHT...THEN QUIET CONDITIONS ARE EXPECTED. && .HYDROLOGY... UP TO 2 INCHES OF RAINFALL POSSIBLE LATE TONIGHT THROUGH FRI NIGHT. THE HEAVIEST RAIN WILL FALL MOSTLY NW OF THE LOW CENTER INITIALLY LATE TONIGHT INTO FRI MORNING...FROM NYC METRO AND POINTS NORTH/WEST...BUT THEN HEAVY RAIN FOCUS SHOULD SHIFT TO LONG ISLAND AND SOUTHERN CT IN THE AFTERNOON JUST AHEAD OF THE LOW AS IT MOVES ACROSS. MAIN CONCERN IS FOR MINOR FLOODING. ISOLD FLASH FLOODING COULD OCCUR WITH HEAVIEST TSTMS FRI AFTERNOON AND EARLY EVENING ACROSS LONG ISLAND AND SOUTHERN CT...BUT THIS THREAT APPEARS TOO LOW/ISOLD TO WARRANT A WATCH. A STORM TOTAL GRAPHIC HAS BEEN POSTED TO THE WEB. && .TIDES/COASTAL FLOODING... COMBO OF HIGH ASTRONOMICAL HIGH TIDES WITH THE UPCOMING FULL MOON PLUS ABOUT 1 TO 1.5 FT OF SURGE AHEAD OF THE LOW APPROACHING TONIGHT AND MOVING ACROSS ON FRI COULD LEAD TO ISOLATED MINOR COASTAL FLOODING AT THE TIMES OF HIGH TIDE FRI NIGHT IN THE MOST VULNERABLE LOCATIONS ALONG THE SOUTH SHORE BACK BAYS OF WRN LONG ISLAND...AND ALONG WRN LONG ISLAND SOUND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO NOON EDT FRIDAY FOR ANZ335- 338-345. SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT FRIDAY FOR ANZ330- 340. SMALL CRAFT ADVISORY FROM 2 AM TO 6 PM EDT FRIDAY FOR ANZ350- 353-355. && $$ SYNOPSIS...GOODMAN/JP NEAR TERM...GOODMAN SHORT TERM...GOODMAN LONG TERM...JP AVIATION...NV MARINE...GOODMAN/JP HYDROLOGY...GOODMAN TIDES/COASTAL FLOODING...GOODMAN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1056 AM EDT THU SEP 27 2012 .SYNOPSIS... A COLD FRONT WILL STALL ACROSS THE REGION TODAY. SEVERAL WAVES OF LOW PRESSURE ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY THROUGH THE WEEKEND. ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO MOVE OUT OF THE GREAT LAKES REGION INTO NEW ENGLAND SUNDAY INTO MONDAY BEFORE HIGH PRESSURE MOVES ACROSS OUR AREA. THIS MAY HELP MOVE THE FRONTAL BOUNDARY ALONG AND PROVIDE DRIER WEATHER TUESDAY INTO WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A RATHER NARROW AND QUITE SPOTTY BAND OF SHOWERS RUNNING ACROSS THE FORECAST AREA MAINLY NORTH OF A MQS TO PHL TO BLM LINE AT MID MORNING LIKELY WAS TIED TO SOME WEAKENING AND CHANNELED H5 VORTICITY STRINGING ALONG OVER THE AREA. THE HRRR GUIDANCE, AS OFTEN IS THE CASE, HAS NOT BEEN HANDLING THIS CONSISTENTLY. THE NEW NAM20 TAKES THE VORTICITY AWAY BY AROUND NOON. ONLY SOME ISOLATED NUISANCE SHOWERS ARE FORECAST FOR THE BALANCE OF THE AFTERNOON CENTRAL AND NORTH, AND LITTLE OR NO THREAT OF ANY MORNING ACTIVITY IS FORECAST SOUTH. MEANWHILE, A MID LEVEL SHORT WAVE MOVING OUT OF INDIANA THIS MORNING WILL MOVE EAST AND IS EXPECTED TO REACH WESTERN PENNSYLVANIA THIS EVENING. A WEAK SURFACE LOW ASSOCIATED WITH THE SHORT WAVE ALSO WILL APPROACH DURING THE COURSE OF THE DAY. AFTER CARVING OUT A FEW HOURS CENTERED AROUND NOON WITH NO RAIN FORECAST, WE CARRY INCREASING CHANCES DURING THE AFTERNOON FROM WEST TO EAST, BUT THOSE CHANCES DON`T EXCEED THE LOW CHANCE RANGE. WITH MARGINAL INSTABILITY FOR THE MID TO LATE AFTERNOON HOURS, WE MENTION SCATTERED TO ISOLATED RAIN SHOWERS ALONG WITH THE POTENTIAL FOR ISOLATED THUNDERSTORMS. WITH SOME SUNSHINE EXPECTED THROUGH THE CLOUDS TODAY, AFTERNOON TEMPERATURES ARE FORECAST TO RISE INTO THE MIDDLE 70S TO THE LOWER 80S. READINGS IN OUR NORTHERN COUNTIES MAY GET NO HIGHER THAN THE UPPER 60S AND THE LOWER 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/... FOR TONIGHT, THE MID LEVEL SHORT WAVE IS EXPECTED TO PROGRESS FROM OHIO TO CENTRAL PENNSYLVANIA. THE SURFACE LOW IS FORECAST TO REACH PENNSYLVANIA`S SUSQUEHANNA RIVER VALLEY LATE TONIGHT. A PUSH OF WARM MOIST AIR AHEAD OF THE SYSTEM WILL LIKELY RESULT IN RAIN OVERSPREADING MUCH OF OUR REGION TONIGHT. BASED ON THE LATEST MODEL GUIDANCE, IT APPEARS AS THOUGH THE BETTER CHANCES FOR RAIN AND THE HIGHER RAINFALL AMOUNTS SHOULD BE ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY WITH SOMEWHAT LOWER NUMBERS FOR SOUTHERN NEW JERSEY AND FOR THE UPPER DELMARVA. WE WILL CONTINUE TO MENTION A SLIGHT CHANCE OF THUNDERSTORMS WITH SOME MARGINAL INSTABILITY LINGERING AND THE INCREASING LIFT DUE TO THE APPROACHING SYSTEM FROM THE WEST. WITH THE CLOUD COVER AND A LIGHT EAST TO SOUTHEAST FLOW, MINIMUM TEMPERATURES SHOULD DROP ONLY INTO THE UPPER 50S TO THE MIDDLE 60S FOR TONIGHT. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... UNSETTLED WEATHER CONTINUES TO BE FORECAST FOR THE END OF THE WEEK INTO THE WEEKEND, BEFORE A POSSIBLE DRYING OUT PERIOD. ON FRIDAY, AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE FRONTAL BOUNDARY THAT CROSSES THE AREA TODAY AND STALLS TO OUR SOUTH. ALL MODEL GUIDANCE IS FORECASTING THE LOW TO TRACK RIGHT ACROSS OUR AREA ON FRIDAY. FORECAST QPFS ARE HIGHEST ACROSS OUR NORTHERN ZONES AND FURTHER NORTH OF OUR AREA SINCE THE STRONGEST FORCING FROM THE SHORT WAVE/VORT MAX ALOFT ARE FURTHER NORTH. WE HAVE KEPT THE SLIGHT CHANCE OF THUNDERSTORMS IN THE FORECAST SINCE THERE IS STILL SOME INSTABILITY FORECAST. AREAS ON THE NORTHERN SIDE OF THE LOW PRESSURE HAVE LESS OF A CHANCE THAN AREAS FURTHER SOUTH. BY FRIDAY NIGHT INTO SATURDAY, IT IS POSSIBLE THAT THE FRONTAL BOUNDARY MAY PUSH FAR ENOUGH SOUTH AND EAST OF THE AREA THAT WE MAY HAVE A BRIEF DRYING PERIOD. HOWEVER, DUE TO THE CLOSENESS OF THE FRONT AND THE FACT MULTIPLE DISTURBANCES ALOFT WILL AFFECT THE AREA, WE WILL KEEP A CHANCE OF PRECIPITATION FOR AT LEAST THE EASTERN PORTION OF THE AREA. SUNDAY BRINGS ANOTHER ENHANCED PROBABILITY OF PRECIPITATION ACROSS THE AREA. A CLOSED LOW ALOFT AND ITS SURFACE LOW ARE FORECAST TO MOVE OUT OF CANADA AND INTO THE GREAT LAKES, BEFORE MOVING INTO NEW ENGLAND SUNDAY INTO SUNDAY NIGHT. THIS MAY BRING ENOUGH MOISTURE AND LIFT ACROSS THE AREA TO PROVIDE A FOCUS FOR ADDITIONAL SHOWERS TO OCCUR. THE GREATEST PROBABILITY MAY BE NORTH OF OUR AREA, BUT WE KEEP A CHANCE OF SHOWERS THROUGH SUNDAY NIGHT. WITH NOT MUCH INSTABILITY EXPECTED, THUNDER WAS LEFT OUT OF THE FORECAST. WE MAY THEN GET A DRYING OUT PERIOD AS WE GO INTO EARLY NEXT WEEK. THERE MAY BE A FEW LINGERING SHOWERS EARLY MONDAY AS THE AFOREMENTIONED LOW PULLS AWAY FROM THE AREA, BUT AFTER THAT, HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA TUESDAY INTO WEDNESDAY. TEMPERATURES THROUGH THE EXTENDED ARE EXPECTED TO BE A FEW DEGREES ABOVE NORMAL, WITH THE WEEKEND BEING THE COOLEST WHICH MAY END UP BEING VERY CLOSE TO NORMAL. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THE STALLING FRONT AND THE STRING OF SPOTTY SHOWER ACTIVITY THIS MORNING WAS MAKING IT DIFFICULT FOR SITES FROM PHL NORTH TO CONSISTENTLY RISE OUT OF THE MVFR OR IFR RANGE. WE PRESENTLY ARE FORECASTING THAT ACTIVITY TO DISSIPATE BY AROUND 16Z OR 17Z. CONFIDENCE IN THIS IS LOW TO MODERATE. SOUTH OF PHL, OUR FORECAST IS FOR VFR CONDITIONS FOR THE BALANCE OF THE DAY. CONFIDENCE IN THIS IS MODERATE. WEAK LOW PRESSURE APPROACHING FROM THE WEST IS FORECAST TO SPREAD RAIN INTO OUR REGION FOR TONIGHT. CONDITIONS ARE EXPECTED TO LOWER INTO THE MVFR CATEGORY AT MOST LOCATIONS. BRIEF PERIODS OF IFR ARE POSSIBLE IN POCKETS OF MODERATE TO HEAVY RAIN, ESPECIALLY AT KRDG AND KABE. ANY THUNDERSTORM ACTIVITY FOR THIS AFTERNOON INTO TONIGHT SHOULD BE VERY ISOLATED AND IT WILL NOT BE MENTIONED IN THE TAFS. THE WIND IS FORECAST TO BE MOSTLY AT 8 KNOTS OR LESS FOR TODAY AT VARYING DIRECTIONS. THE WIND SHOULD SETTLE INTO THE EAST TO SOUTH QUADRANT FOR TONIGHT AT SPEEDS OF 10 KNOTS OR LESS. OUTLOOK... FRIDAY...PERIODS OF RAIN WITH MVFR/IFR CONDITIONS EXPECTED. FRIDAY NIGHT-SATURDAY...CONDITIONS POSSIBLY IMPROVING TO VFR...STILL A CHANCE OF MVFR CONDITIONS. SATURDAY NIGHT-SUNDAY NIGHT...PERIODS OF RAIN WITH MVFR/IFR CONDITIONS POSSIBLE. MONDAY...CONDITIONS IMPROVING TO VFR. && .MARINE... A WEAK FRONTAL BOUNDARY FROM THE NORTHWEST WILL DROP INTO OUR REGION FOR TODAY. WEAK LOW PRESSURE IS FORECAST TO APPROACH FROM THE WEST FOR TONIGHT. WIND SPEEDS AND WAVE HEIGHTS ARE ANTICIPATED TO REMAIN BELOW THE SMALL CRAFT ADVISORY CRITERIA DURING TODAY AND TONIGHT. OUTLOOK... THE FRONTAL BOUNDARY IS EXPECTED TO REMAIN STALLED ACROSS THE AREA THROUGH THE END OF THE WEEK AND INTO THE WEEKEND. WINDS MAY PERIODICALLY GUST AROUND 15-20 KNOTS. HOWEVER, WINDS AND WAVES ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS. SEVERAL WAVES OF LOW PRESSURE MAY DEVELOP ALONG THE BOUNDARY, WHICH WILL HAVE AN EFFECT ON WIND DIRECTION. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...ROBERTSON/DELISI NEAR TERM...IOVINO/DELISI SHORT TERM...IOVINO LONG TERM...ROBERTSON AVIATION...IOVINO/ROBERTSON/DELISI MARINE...IOVINO/ROBERTSON
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1007 AM EDT THU SEP 27 2012 .SYNOPSIS... A COLD FRONT WILL STALL ACROSS THE REGION TODAY. SEVERAL WAVES OF LOW PRESSURE ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY THROUGH THE WEEKEND. ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO MOVE OUT OF THE GREAT LAKES REGION INTO NEW ENGLAND SUNDAY INTO MONDAY BEFORE HIGH PRESSURE MOVES ACROSS OUR AREA. THIS MAY HELP MOVE THE FRONTAL BOUNDARY ALONG AND PROVIDE DRIER WEATHER TUESDAY INTO WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A RATHER NARROW AND QUITE SPOTTY BAND OF SHOWERS RUNNING ACROSS THE FORECAST AREA MAINLY NORTH OF A MQS TO PHL TO BLM LINE AT MID MORNING LIKELY WAS TIED TO SOME WEAKENING AND CHANNELED H5 VORTICITY STRINGING ALONG OVER THE AREA. THE HRRR GUIDANCE, AS OFTEN IS THE CASE, HAS NOT BEEN HANDLING THIS CONSISTENTLY. THE NEW NAM20 TAKES THE VORTICITY AWAY BY AROUND NOON. ONLY SOME ISOLATED NUISANCE SHOWERS ARE FORECAST FOR THE BALANCE OF THE AFTERNOON CENTRAL AND NORTH, AND LITTLE OR NO THREAT OF ANY MORNING ACTIVITY IS FORECAST SOUTH. MEANWHILE, A MID LEVEL SHORT WAVE MOVING OUT OF INDIANA THIS MORNING WILL MOVE EAST AND IS EXPECTED TO REACH WESTERN PENNSYLVANIA THIS EVENING. A WEAK SURFACE LOW ASSOCIATED WITH THE SHORT WAVE ALSO WILL APPROACH DURING THE COURSE OF THE DAY. AFTER CARVING OUT A FEW HOURS CENTERED AROUND NOON WITH NO RAIN FORECAST, WE CARRY INCREASING CHANCES DURING THE AFTERNOON FROM WEST TO EAST, BUT THOSE CHANCES DON`T EXCEED THE LOW CHANCE RANGE. WITH MARGINAL INSTABILITY FOR THE MID TO LATE AFTERNOON HOURS, WE MENTION SCATTERED TO ISOLATED RAIN SHOWERS ALONG WITH THE POTENTIAL FOR ISOLATED THUNDERSTORMS. WITH SOME SUNSHINE EXPECTED THROUGH THE CLOUDS TODAY, AFTERNOON TEMPERATURES ARE FORECAST TO RISE INTO THE MIDDLE 70S TO THE LOWER 80S. READINGS IN OUR NORTHERN COUNTIES MAY GET NO HIGHER THAN THE UPPER 60S AND THE LOWER 70S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/... FOR TONIGHT, THE MID LEVEL SHORT WAVE IS EXPECTED TO PROGRESS FROM OHIO TO CENTRAL PENNSYLVANIA. THE SURFACE LOW IS FORECAST TO REACH PENNSYLVANIA`S SUSQUEHANNA RIVER VALLEY LATE TONIGHT. A PUSH OF WARM MOIST AIR AHEAD OF THE SYSTEM WILL LIKELY RESULT IN RAIN OVERSPREADING MUCH OF OUR REGION TONIGHT. BASED ON THE LATEST MODEL GUIDANCE, IT APPEARS AS THOUGH THE BETTER CHANCES FOR RAIN AND THE HIGHER RAINFALL AMOUNTS SHOULD BE ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY WITH SOMEWHAT LOWER NUMBERS FOR SOUTHERN NEW JERSEY AND FOR THE UPPER DELMARVA. WE WILL CONTINUE TO MENTION A SLIGHT CHANCE OF THUNDERSTORMS WITH SOME MARGINAL INSTABILITY LINGERING AND THE INCREASING LIFT DUE TO THE APPROACHING SYSTEM FROM THE WEST. WITH THE CLOUD COVER AND A LIGHT EAST TO SOUTHEAST FLOW, MINIMUM TEMPERATURES SHOULD DROP ONLY INTO THE UPPER 50S TO THE MIDDLE 60S FOR TONIGHT. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... UNSETTLED WEATHER CONTINUES TO BE FORECAST FOR THE END OF THE WEEK INTO THE WEEKEND, BEFORE A POSSIBLE DRYING OUT PERIOD. ON FRIDAY, AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP ALONG THE FRONTAL BOUNDARY THAT CROSSES THE AREA TODAY AND STALLS TO OUR SOUTH. ALL MODEL GUIDANCE IS FORECASTING THE LOW TO TRACK RIGHT ACROSS OUR AREA ON FRIDAY. FORECAST QPFS ARE HIGHEST ACROSS OUR NORTHERN ZONES AND FURTHER NORTH OF OUR AREA SINCE THE STRONGEST FORCING FROM THE SHORT WAVE/VORT MAX ALOFT ARE FURTHER NORTH. WE HAVE KEPT THE SLIGHT CHANCE OF THUNDERSTORMS IN THE FORECAST SINCE THERE IS STILL SOME INSTABILITY FORECAST. AREAS ON THE NORTHERN SIDE OF THE LOW PRESSURE HAVE LESS OF A CHANCE THAN AREAS FURTHER SOUTH. BY FRIDAY NIGHT INTO SATURDAY, IT IS POSSIBLE THAT THE FRONTAL BOUNDARY MAY PUSH FAR ENOUGH SOUTH AND EAST OF THE AREA THAT WE MAY HAVE A BRIEF DRYING PERIOD. HOWEVER, DUE TO THE CLOSENESS OF THE FRONT AND THE FACT MULTIPLE DISTURBANCES ALOFT WILL AFFECT THE AREA, WE WILL KEEP A CHANCE OF PRECIPITATION FOR AT LEAST THE EASTERN PORTION OF THE AREA. SUNDAY BRINGS ANOTHER ENHANCED PROBABILITY OF PRECIPITATION ACROSS THE AREA. A CLOSED LOW ALOFT AND ITS SURFACE LOW ARE FORECAST TO MOVE OUT OF CANADA AND INTO THE GREAT LAKES, BEFORE MOVING INTO NEW ENGLAND SUNDAY INTO SUNDAY NIGHT. THIS MAY BRING ENOUGH MOISTURE AND LIFT ACROSS THE AREA TO PROVIDE A FOCUS FOR ADDITIONAL SHOWERS TO OCCUR. THE GREATEST PROBABILITY MAY BE NORTH OF OUR AREA, BUT WE KEEP A CHANCE OF SHOWERS THROUGH SUNDAY NIGHT. WITH NOT MUCH INSTABILITY EXPECTED, THUNDER WAS LEFT OUT OF THE FORECAST. WE MAY THEN GET A DRYING OUT PERIOD AS WE GO INTO EARLY NEXT WEEK. THERE MAY BE A FEW LINGERING SHOWERS EARLY MONDAY AS THE AFOREMENTIONED LOW PULLS AWAY FROM THE AREA, BUT AFTER THAT, HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA TUESDAY INTO WEDNESDAY. TEMPERATURES THROUGH THE EXTENDED ARE EXPECTED TO BE A FEW DEGREES ABOVE NORMAL, WITH THE WEEKEND BEING THE COOLEST WHICH MAY END UP BEING VERY CLOSE TO NORMAL. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THE STRING OF SPOTTY SHOWER ACTIVITY THIS MORNING WAS MAKING IT DIFFICULT FOR SITES NORTH OF PHL TO CONSITENTLY RISE OUT OF THE MVFR OR IFR RANGE. WE PRESENTLY ARE FORECASTING THAT ACTIVITY TO DISSIPATE BY AROUND 16Z. CONFIDENCE IN THIS IS LOW TO MODERATE. FROM PHL SOUTH, OUR FORECAST IS FOR VFR CONDITIONS FOR THE BALANCE OF THE DAY. CONFIDENCE IN THIS IS MODERATE. WEAK LOW PRESSURE APPROACHING FROM THE WEST IS FORECAST TO SPREAD RAIN INTO OUR REGION FOR TONIGHT. CONDITIONS ARE EXPECTED TO LOWER INTO THE MVFR CATEGORY AT MOST LOCATIONS. BRIEF PERIODS OF IFR ARE POSSIBLE IN POCKETS OF MODERATE TO HEAVY RAIN, ESPECIALLY AT KRDG AND KABE. ANY THUNDERSTORM ACTIVITY FOR THIS AFTERNOON INTO TONIGHT SHOULD BE VERY ISOLATED AND IT WILL NOT BE MENTIONED IN THE TAFS. THE WIND IS FORECAST TO BE MOSTLY AT 8 KNOTS OR LESS FOR TODAY AT VARYING DIRECTIONS. THE WIND SHOULD SETTLE INTO THE EAST TO SOUTH QUADRANT FOR TONIGHT AT SPEEDS OF 10 KNOTS OR LESS. OUTLOOK... FRIDAY...PERIODS OF RAIN WITH MVFR/IFR CONDITIONS EXPECTED. FRIDAY NIGHT-SATURDAY...CONDITIONS POSSIBLY IMPROVING TO VFR...STILL A CHANCE OF MVFR CONDITIONS. SATURDAY NIGHT-SUNDAY NIGHT...PERIODS OF RAIN WITH MVFR/IFR CONDITIONS POSSIBLE. MONDAY...CONDITIONS IMPROVING TO VFR. && .MARINE... A WEAK FRONTAL BOUNDARY FROM THE NORTHWEST WILL DROP INTO OUR REGION FOR TODAY. WEAK LOW PRESSURE IS FORECAST TO APPROACH FROM THE WEST FOR TONIGHT. WIND SPEEDS AND WAVE HEIGHTS ARE ANTICIPATED TO REMAIN BELOW THE SMALL CRAFT ADVISORY CRITERIA DURING TODAY AND TONIGHT. OUTLOOK... THE FRONTAL BOUNDARY IS EXPECTED TO REMAIN STALLED ACROSS THE AREA THROUGH THE END OF THE WEEK AND INTO THE WEEKEND. WINDS MAY PERIODICALLY GUST AROUND 15-20 KNOTS. HOWEVER, WINDS AND WAVES ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS. SEVERAL WAVES OF LOW PRESSURE MAY DEVELOP ALONG THE BOUNDARY, WHICH WILL HAVE AN EFFECT ON WIND DIRECTION. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...ROBERTSON/DELISI NEAR TERM...IOVINO/DELISI SHORT TERM...IOVINO LONG TERM...ROBERTSON AVIATION...IOVINO/ROBERTSON/DELISI MARINE...IOVINO/ROBERTSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
812 PM EDT FRI SEP 28 2012 .UPDATE... ONLY ISOLATED SHOWERS AND THUNDERSTORMS REMAIN THIS EVENING ACROSS COLLIER AND MAINLAND MONROE COUNTIES, AND ACROSS THE GULF COASTAL WATERS. LATEST HRRR DEPICTS A SLOW DECREASE IN COVERAGE THROUGH THE OVERNIGHT HOURS. DECREASED POPS THROUGH THE EVENING TO ADJUST FOR CURRENT TRENDS AND KEPT HIGHER POPS ALONG THE GULF WATERS. OTHERWISE, ONGOING FORECAST LOOKS GOOD. UPDATE WILL BE SENT SHORTLY. && .PREV DISCUSSION... /ISSUED 740 PM EDT FRI SEP 28 2012/ AVIATION... THE WEATHER SHOULD BE DRY OVER MOST OF THE TAF SITES TONIGHT...EXCEPT FOR A FEW SHOWERS OVER THE WEST COAST METRO AREAS UNTIL 00Z. KTMB AND KAPF CAN ALSO SEE SOME FOG LATE TONIGHT INTO EARLY SATURDAY MORNING WHICH CAN REDUCE VIS DOWN INTO THE MVFR CONDITIONS. THE WINDS WILL ALSO BE LIGHT AND VARIABLE TONIGHT AT ALL OF THE TAF SITES ACROSS SOUTH FLORIDA. ON SATURDAY...THE WINDS WILL BECOME EASTERLY AT 5 TO 10 KNOTS AFTER 15Z AT ALL OF THE TAF SITES. KAPF TAF SITE WILL ALSO SEE THE WINDS SWING TO A WESTERLY DIRECTION AFTER 18Z...DUE TO THE WEST COAST SEA BREEZE DEVELOPING AND PUSHING INLAND. THERE COULD ALSO BE SOME SHOWERS OVER THE EAST COAST METRO AREAS ON SATURDAY AND A FEW THUNDERSTORMS OVER THE WEST COAST. SO WILL PUT IN VCSH FOR THE EAST COAST TAF SITES AFTER 15Z ON SATURDAY AND VCTS AT KAPF TAF SITE AFTER 18Z. AVIATION...54/BNB PREV DISCUSSION... /ISSUED 242 PM EDT FRI SEP 28 2012/ DISCUSSION...MID/UPPER LEVEL TROUGH CURRENTLY MOVING ACROSS SOUTH FLORIDA WHICH IS ROTATING AT THE BASE OF A LARGER SCALE TROUGH OVER THE EASTERN U.S. AND ALSO SANDWICHED BETWEEN A STRONG RIDGE OF HIGH PRESSURE OVER THE WESTERN GULF OF MEXICO AND THE ATLANTIC NORTHEAST OF THE BAHAMAS. AT THE SURFACE, A WEAK RIDGE EXTENDS OVER NORTH FLORIDA WITH A WEAK LOW LEVEL EAST WIND FLOW ACROSS OUR REGION. THIS ALONG WITH THE TROUGH OVERHEAD HAS ALSO GENERATED A VERY WEAK STEERING FLOW WITH AN EAST FLOW LESS THAN 10 KNOTS BELOW 10K FEET AND NEARLY CALM ABOVE THAT LEVEL. THUS, STORM MOTION WILL BE DRIVEN BY SEA BREEZES FOLLOWED BY OUTFLOW BOUNDARY INTERACTIONS. MID LEVEL LAPSE RATES ARE SOMEWHAT IMPRESSIVE (ESPECIALLY FOR SOUTH FLORIDA STANDARDS) WITH 50H TEMP OF -10 WHICH IS CONSIDERABLY BELOW THE AVERAGE FOR LATE SEPTEMBER. ALL OF THIS WILL LEAD FOR THE POTENTIAL FOR SHORT LIVED SEVERE BY LATE THIS AFTERNOON ALONG WITH POSSIBLE LOCALIZED URBAN TYPE FLOODING WITH VERY SATURATED GROUNDS FROM SEVERAL WEEKS OF ABOVE NORMAL RAINFALL ALONG THE EAST COAST METRO REGION. THE MID LEVEL TROUGH WILL MOVE SOUTH OF THE PENINSULA OVER THE WEEKEND WITH A RETURN TO ZONAL FLOW BY SUNDAY. LATE IN THE WEEKEND, A STRONG MID LEVEL TROUGH WILL DEEPEN ACROSS THE SOUTHERN GULF STATES INTO EARLY NEXT WEEK BEFORE LIFTING TO THE NORTHEAST BY WEDNESDAY OR THURSDAY. THIS WILL PROVIDE SOUTH FLORIDA WITH A DEEP SOUTHERLY FLOW OF AIR WITH A CONTINUATION OF HIGH PWAT`S AND INSTABILITY. CHANCES OF RAIN WILL BE AT LEAST HIGH END SCATTERED AND POSSIBLY NUMEROUS FOR THE FIRST SEVERAL DAYS OF OCTOBER. ANOTHER REASON FOR KEEPING ACTIVE WEATHER ACROSS FLORIDA WILL BE A WEAK COLD FRONT SAGGING SOUTH DOWN THE PENINSULA NEXT WEEK RESULTING FROM THE MID LEVEL TROUGH. MARINE...LIGHT EAST TO NORTHEAST WINDS AND SEAS WILL PERSIST THROUGH THE BULK OF THE WEEKEND AS HIGH PRESSURE REMAINS IN CONTROL NORTH OF THE MARINE AREAS. THE BEST CHANCE FOR SHOWERS OR STORMS WILL REMAIN THROUGH THE OVERNIGHT AND EARLY MORNING HOURS. LATER IN THE WEEKEND AND INTO EARLY NEXT WEEK...WINDS WILL SHIFT TOWARD THE SOUTH AS A LOW PRESSURE SYSTEM DEVELOPS OVER THE NORTHERN GULF OF MEXICO AND TRACKS EAST TO NORTHEAST. FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH RH VALUES WELL ABOVE CRITICAL LEVELS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 87 77 88 / 20 20 20 40 FORT LAUDERDALE 77 86 77 88 / 20 20 20 40 MIAMI 77 88 77 89 / 20 20 20 50 NAPLES 75 89 76 89 / 20 20 20 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...10/CD AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION...CORRECTED
NWS TAMPA BAY RUSKIN FL
330 AM EDT THU SEP 27 2012 .SYNOPSIS... 07Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN OVERALL LESS AMPLIFIED UPPER LEVEL PATTERN...WITH MAINLY ZONAL FLOW IN PLACE OVER THE SOUTHEASTERN STATES. MAIN LONGWAVE TROUGH WITHIN THE NORTHERN STREAM FLOW IS LOCATED OVER EASTERN CANADA/NEW ENGLAND WITH AN AXIS WHICH IS QUICKLY PIVOTING EASTWARD TOWARD THE CANADIAN MARITIME REGION. FAIRLY POTENT SHORTWAVE ENERGY REMAIN IN PLACE OVER THE INTER-MOUNTAIN WEST EARLY THIS MORNING...BUT IS EXPECTED TO SHEAR OUT AND DISSIPATE AS IT BEGINS TO EJECT EASTWARD LATER TODAY/TONIGHT. AT THE SURFACE...SURFACE RIDGE HAS MOVED LITTLE IN THE PAST 24 HOURS AND REMAINS ALIGNED FROM THE CAROLINA COAST TO NORTHERN GA/AL. OUR FORECAST AREA/FL PENINSULA REMAIN WITHIN A MOIST EASTERLY FLOW AROUND THE SOUTHERN PERIPHERY OF THE RIDGE WITH REGIONAL DEWPOINTS BACK INTO THE LOWER 70S. VERY LITTLE TO MENTION EARLY THIS MORNING ON REGIONAL RADARS AS THERE IS LITTLE IN THE WAY OF SYNOPTIC INFLUENCE FOR LIFT CURRENTLY OVERHEAD. SIMILAR TO TUESDAY NIGHT...THE DEEP MOISTURE IS EXPECTED TO LEAD TO AREAS OF FOG BY DAWN. THE FACT THAT WE ARE SEEING A SIGNIFICANT THINNING OF THE UPPER LEVEL CIRRUS EARLY THIS MORNING WILL ONLY HELP TO FURTHER PROMOTE THE FOG FORMATION. && .SHORT TERM (TODAY THROUGH SATURDAY)... TODAY/TONIGHT...OVERALL PATTERN LOOKS VERY SIMILAR TO WEDNESDAY WITH CONTINUED EASTERLY FLOW AND A FAIRLY MOIST MIDDLE AND LOWER LEVEL PROFILE. WITHOUT ANY SIGNIFICANT SYNOPTIC FEATURES TO ENHANCE LIFT AND LITTLE IF ANY SEA-BREEZE INFLUENCE...SHOWERS/STORMS SHOULD BE WIDELY SCATTERED IN NATURE ONCE AGAIN. HAVE GONE WITH A GENERAL 30% POP...WITH THE EARLIEST TIMING FOR SHOWERS OVER INLAND AREAS. INITIAL CONVECTION SHOULD BE OVER NEAR THE EAST COAST AND PROPAGATE INLAND WITH TIME. LATER DAY CONVECTION CLOSER TO THE WEST COAST WILL FIRE ALONG OUTFLOW BOUNDARIES FROM THIS FIRST WAVE OF SHOWERS THAT FURTHER PROPAGATE WESTWARD WITHIN THE SYNOPTIC FLOW. OF NOTE...MANY OF THE CONVECTION ALLOWING HIGH RESOLUTION GUIDANCE MEMBERS... INCLUDING THE LOCAL 4KM WRF-ARW...SUGGEST THE BEST COVERAGE OF SHOWERS DURING THE AFTERNOON WILL BE OVER THE NATURE COAST ZONES. WILL LET THE NEXT SHIFT EVALUATE LATER GUIDANCE SUITES BEFORE POTENTIALLY RAISING POPS TO THE NORTH OF I-4. A BIT MORE INSOLATION EXPECTED TODAY...ESPECIALLY THIS MORNING WITH LESS IN THE WAY OF UPPER LEVEL CIRRUS. THIS ENHANCED SOLAR RADIATION SHOULD ALLOW MORE LOCATIONS TO REACH THE LOWER 90S FOR HIGH TEMPERATURES. ANY LINGERING SHOWERS AND STORMS WILL DISSIPATE WITHIN A FEW HOURS OF SUNSET RESULTING IN A GENERALLY DRY FORECAST OVERNIGHT AND EARLY FRIDAY MORNING. FRIDAY...RIDGE CENTER TO OUR NORTH WILL BE WEAKENING WITH A RESULTING WEAKENING OF THE LOCAL GRADIENT. FOR THIS REASON WE MAY SEE THE FIRST REAL DEFINED SEA-BREEZE CIRCULATION IN SEVERAL DAYS DEVELOP NEAR THE COAST DURING THE AFTERNOON. FRIDAY LOOKS SEASONABLE IN TERMS OF BOTH TEMPERATURES AND RAIN CHANCES...AND WILL NOT DEVIATE MUCH FROM THE MAV NUMBERS. SATURDAY...ANOTHER SEASONABLE DAY ON TAP WITH TEMPS NEAR 90 FOR MOST LOCATIONS AND WIDELY SCT MAINLY AFTERNOON/EVENING STORMS. WHILE NOT DIRECTLY INFLUENCING OUR WEATHER QUITE YET DURING THE FIRST HALF OF THE WEEKEND...WE WILL BEGIN TO SEE THE FIRST STAGES OF AN EXPECTED SIGNIFICANT AMPLIFICATION TO THE PATTERN DEVELOPING OVER THE EASTERN CONUS. THIS DEVELOPING PATTERN WILL BE A SIGNIFICANT PLAYER IN OUR WEATHER HEADING INTO NEXT WEEK. MORE ON ALL THIS IN THE LONG TERM DISCUSSION BELOW. && .LONG TERM (SUNDAY THROUGH NEXT WEDNESDAY)... MODELS HAVE COME INTO MUCH BETTER AGREEMENT REGARDING THE EASTERN U.S. TROUGH AND ASSOCIATED SURFACE FEATURES. THAT SAID...THERE ARE DIFFERENCES FROM WHAT WE SAW YESTERDAY...AND STILL TIME FOR THE MODELS TO CHANGE THEIR SOLUTIONS SEVERAL TIMES BETWEEN NOW AND THE WEEKEND. ONE NOTABLE TREND IS THAT THE 500MB CUTOFF LOW HAS BEEN FARTHER WEST WITH EACH RUN AND IS NOW NEAR THE TEXAS/LOUISIANA BORDER LATE TUESDAY. OUR LOWEST 500MB HEIGHTS ARE ON MONDAY...THEN MODELS BRING THE ATLANTIC RIDGE SMARTLY WESTWARD BY WEDNESDAY. THAT WOULD BLOCK ANY EASTWARD PROGRESSION OF THE FRONT AND LIKELY EVEN PUSH IT BACK TO THE NORTHWEST. BOTH THE 00Z GFS AND THE 12Z ECMWF SHOW THE SURFACE RIDGE BUILDING BACK ACROSS THE REGION...TURNING OUR WINDS FROM SOUTHERLY EARLY IN THE WEEK BACK TO SOUTHEASTERLY BY MID-WEEK. THERE IS STILL A CHANCE OF A PERIOD OF WET WEATHER BEGINNING LATE SUNDAY AND EXTENDING THROUGH TUESDAY. THE UPPER-LEVEL TROUGH WILL BE THE MOST PRONOUNCED AND FARTHEST EAST DURING THIS TIME WITH THE SURFACE BOUNDARY ALONG THE NORTHERN GULF COAST. BY WEDNESDAY WE RETURN TO A SUMMER-TIME PATTERN MORE TYPICAL OF AUGUST WITH HIGH MOISTURE CONTENT BUT VERY LITTLE SYNOPTIC SCALE LIFT. THE GFS FORECASTS A RIBBON OF VERY HIGH PRECIPITABLE WATERS...IN EXCESS OF 2.25 INCHES...ASSOCIATED WITH A SURFACE TROUGH OR PERHAPS A TROPICAL WAVE MOVING NORTHWEST ACROSS THE REGION ON WEDNESDAY. SINCE THIS IS DAY 7...I PREFER NOT TO STRAY TOO FAR FROM CLIMATOLOGY REGARDING RAIN CHANCES THIS FAR OUT. TEMPERATURES WILL RUN SEVERAL DEGREES ABOVE NORMAL DURING THIS PERIOD...ESPECIALLY IF THE CURRENT MODEL TREND CONTINUES...KEEPING MOST OF THE SYNOPTIC SCALE LIFT TO OUR NORTHWEST. && .AVIATION... MAINLY VFR BUT CAN NOT RULE OUT SOME PATCHY FOG AND LOW CLOUDS AGAIN AROUND SUNRISE. THE MOST LIKELY LOCATIONS WOULD BE LAL AND PGD BUT SOME LOW CLOUDS COULD ALSO MOVE INTO TPA...PIE AND SRQ. && .MARINE... THE HIGH PRESSURE RIDGE TO OUR NORTH WILL SLOWLY WEAKEN DURING THE NEXT COUPLE OF DAYS ALLOWING THE LOCAL GRADIENT TO ALSO WEAKEN. WINDS AND SEAS ARE EXPECTED TO REMAIN WELL BELOW HEADLINE CRITERIA THROUGH AT LEAST THE FIRST HALF OF THE UPCOMING WEEKEND. && .FIRE WEATHER... ABUNDANT ATLANTIC MOISTURE ARRIVING ON EASTERLY FLOW WILL KEEP RELATIVE HUMIDITY VALUES WELL ABOVE CRITICAL LEVELS THROUGH THE UPCOMING WEEKEND. NO SIGNIFICANT FIRE WEATHER PROBLEMS ARE ANTICIPATED. && .PRELIMINARY POINT TEMPS/POPS... TPA 90 74 90 75 / 30 20 30 20 FMY 90 73 90 73 / 30 20 40 20 GIF 91 72 91 70 / 30 10 30 10 SRQ 89 72 89 72 / 30 20 30 20 BKV 91 69 90 68 / 30 20 30 10 SPG 89 76 89 76 / 30 20 30 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1148 PM CDT WED SEP 26 2012 .DISCUSSION... ISSUED 859 PM CDT WED SEP 26 2012 NEARLY STATIONARY FRONTAL BOUNDARY STILL BISECTING THE FORECAST AREA THIS EVENING...ALTHOUGH THE BULK OF THE PRECIPITATION FALLING IS WELL SOUTH OF THE BOUNDARY. DO NOT EXPECT SIGNIFICANT RAINFALL FOR THE REST OF THE NIGHT...BUT CAN NOT DISCOUNT THE RISK FOR SOME REDEVELOPMENT AS A VIGOROUS WAVE CURRENTLY CROSSING MISSOURI INTERACTS WITH THE FRONT. THE PRESENCE OF THE FRONT...LIGHT WINDS IN ITS VICINITY...AND GRADUALLY CLEARING SKIES FROM THE NORTH POSE A FOG THREAT TONIGHT. HOWEVER...THE FOG THREAT SHOULD BE FURTHER SOUTH TONIGHT THAN IT WAS LAST NIGHT...MOST LIKELY CLOSER TO I-70 CORRIDOR WHERE MORE SIGNIFICANT RAINS HAVE FALLEN LATELY AND SURFACE DEW POINTS WILL BE LAST TO START DROPPING. GOING FORECAST IS IN GOOD SHAPE OVERALL. MAIN CHANGE PLANNED IS TO REDUCE POP AND THUNDER MENTION OVERNIGHT. OTHERWISE...MINOR CHANGES ARE PLANNED FOR THE LATEST TRENDS. BAK && .AVIATION... ISSUED 1148 PM CDT WED SEP 26 2012 A FRONTAL BOUNDARY IS VERY SLOWLY SETTLING SOUTH OF THE CENTRAL ILLINOIS TERMINALS THIS EVENING...WITH WEAK HIGH PRESSURE BUILDING IN BEHIND IT. NORTHEAST WINDS BEHIND THE FRONT ARE USHERING DRIER AIR INTO THE AREA...AND WILL EVENTUALLY RESULT IN CLEAR SKIES AND A DISSIPATION OF ANY FOG. THIS CLEARING/DRYING TREND IS ALREADY OCCURRING AT KPIA...BUT PERIODS OF MVFR CIGS/VSBYS ARE POSSIBLE A THE REMAINING CENTRAL ILLINOIS TAF SITES FOR AT LEAST A FEW HOURS LONGER. VFR CONDITIONS SHOULD PREVAIL AREAWIDE AFTER DAYBREAK THURSDAY...AND LINGER THROUGH THE REST OF THE PERIOD. BAK && .PREV DISCUSSION... ISSUED 221 PM CDT WED SEP 26 2012 RAIN CHANCES WILL PERSIST ACROSS SOUTH-CENTRAL ILLINOIS THROUGH THURSDAY NIGHT...BEFORE A LONG STRETCH OF DRY WEATHER DEVELOPS ACROSS THE ENTIRE REGION THROUGH NEXT WEEK. SHORT TERM...TONIGHT THROUGH SATURDAY 19Z/2PM SURFACE ANALYSIS SHOWS A SLOW-MOVING COLD FRONT EXTENDING FROM JUST SOUTH OF KIKK TO NEAR KUIN. TO THE NORTH OF THE FRONT...WINDS HAVE BECOME NORTHERLY AND A DRIER AIRMASS IS BEGINNING TO SETTLE INTO THE FAR NORTHERN KILX CWA. MEANWHILE SOUTH OF THE BOUNDARY...A MOIST ENVIRONMENT CHARACTERIZED BY DEWPOINTS IN THE 60S IS SUPPORTING SCATTERED SHOWERS/THUNDER ACROSS THE REMAINDER OF THE AREA. COLD FRONT IS NOT EXPECTED TO DROP MUCH FURTHER SOUTH TONIGHT...AS UPPER-LEVEL WAVE CURRENTLY OVER EASTERN KANSAS WILL IMPEDE ITS SOUTHERN PROGRESS. AS A RESULT...THINK FRONT WILL ONLY SINK TO JUST SOUTH OF THE I-72 CORRIDOR OVERNIGHT. AS A RESULT...WILL CONTINUE TO CARRY LOW CHANCE POPS ACROSS THE CENTRAL ZONES...WITH HIGHEST POPS FOCUSED ALONG/SOUTH OF I-70 WHERE DEEPEST MOISTURE AND STRONGEST LIFT WILL BE PRESENT. WITH FRONT IN THE VICINITY AND DRIER AIRMASS ONLY TRICKLING SLOWLY SOUTHWARD...THINK AREAS OF FOG WILL DEVELOP OVERNIGHT. LAST NIGHT...FOG FORMED IN LOCATIONS NEAR/SOUTH OF THE BOUNDARY WHERE DEWPOINTS HOVERED IN THE UPPER 50S/LOWER 60S. THOSE CONDITIONS WILL LIKELY EXIST FURTHER SOUTH TONIGHT...PRIMARILY ALONG/SOUTH OF I-70. NAM FORECAST SOUNDINGS PROVIDE A STRONG SIGNAL FOR FOG AT BOTH KMTO AND KLWV AND HRRR VISBY PROGS SUPPORT THIS AS WELL...SO HAVE INCLUDED AREAS OF FOG ACROSS THE SOUTHEAST AFTER MIDNIGHT. ANY FOG WILL GRADUALLY BURN OFF THURSDAY MORNING...HOWEVER SKIES WILL REMAIN MOSTLY CLOUDY THROUGHOUT THE DAY ACROSS THE SOUTHEAST AS THE FRONT MAKES ONLY VERY SLOW PROGRESS SOUTHWARD. WILL CONTINUE WITH CHANCE POPS ALONG AND SOUTH OF A PARIS TO SHELBYVILLE LINE...WITH DRY CONDITIONS EXPECTED FURTHER NORTH. BOTH THE NAM AND GFS FINALLY GIVE THE BOUNDARY A GOOD PUSH SOUTHWARD BY FRIDAY...AS HIGH PRESSURE BUILDS INTO THE UPPER MIDWEST. WILL HOLD ON TO A SLIM CHANCE FOR A SHOWER SOUTH OF I-70 INTO FRIDAY IN CASE FRONT IS DELAYED...BUT WILL GO WITH MOSTLY SUNNY AND DRY CONDITIONS ELSEWHERE. WITH HIGH PRESSURE BEING THE DOMINANT WEATHER FEATURE...SUNNY SKIES AND DRY WEATHER IS EXPECTED THIS WEEKEND. TEMPERATURES WILL REMAIN NEAR NORMAL FOR THIS TIME OF YEAR...WITH DAYTIME HIGHS IN THE LOWER TO MIDDLE 70S AND OVERNIGHT LOWS IN THE LOWER 50S. LONG TERM...SUNDAY THROUGH WEDNESDAY A VIGOROUS SHORT-WAVE WILL DIVE INTO THE GREAT LAKES LATE IN THE WEEKEND...PUSHING A WEAK COLD FRONT/SURFACE TROUGH THROUGH CENTRAL ILLINOIS SATURDAY NIGHT INTO SUNDAY. SYSTEM WILL HAVE VERY LITTLE MOISTURE TO WORK WITH...SO AM ONLY EXPECTING A FEW CLOUDS AS IT PASSES THROUGH. AFTER THAT...A MAJOR PATTERN CHANGE IS IN STORE NEXT WEEK. BOTH THE GFS AND ECMWF ARE SHOWING AN UPPER-LEVEL RIDGE BUILDING ACROSS THE PLAINS INTO THE MIDWEST BY THE MIDDLE AND END OF THE WEEK. RISING HEIGHTS AND INCREASING SOUTHERLY FLOW WILL BOOST TEMPS WELL INTO THE 70S BY MONDAY AND TUESDAY...THEN PERHAPS INTO THE 80S AFTER THAT. BOTH MODELS INDICATE 850MB TEMPS IN THE 15 TO 17C RANGE BY NEXT WEDNESDAY...SUGGESTING A RETURN TO SUMMER-LIKE WARMTH IN THE EXTENDED. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
655 PM EDT THU SEP 27 2012 .UPDATE... AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 244 PM EDT THU SEP 27 2012 A FRONTAL BOUNDARY WILL SLOWLY SAG SOUTH OF THE OHIO RIVER BY EARLY FRIDAY AND BE REPLACED BY HIGH PRESSURE...BRINGING DRIER WEATHER AND MORE SUNSHINE FOR FRIDAY. A SHARP UPPER LEVEL DISTURBANCE WILL DROP THROUGH THE EASTERN GREAT LAKES OVER THE WEEKEND...USHERING IN A COOLER AIRMASS BY SUNDAY. HIGH PRESSURE AND RIDGING ALOFT WILL PROVIDE FOR DRY WEATHER WITH A WARMING TREND THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TONIGHT/... ISSUED AT 244 PM EDT THU SEP 27 2012 BASED ON OBSERVATIONS AT 18Z...FRONTAL BOUNDARY APPEARS TO BE LOCATED OVER FAR SOUTHEAST SECTIONS OF THE FORECAST AREA. SKIES HAVE SLOWLY CLEARED OVER THE NORTHERN HALF OF THE FORECAST AREA SO FAR THIS AFTERNOON AS DRIER AIR NUDGES INTO THE REGION. HOWEVER AS CONVECTIVE TEMPS ARE REACHED...AREAS ARE FILLING BACK IN WITH CU. TEMPS WERE MAINLY IN THE 60S...ALTHOUGH A FEW LOCATIONS OVER THE WABASH VALLEY HAD WARMED INTO THE 70S WHERE THE MOST SUNSHINE HAD BEEN EXPERIENCED SO FAR. THE FRONTAL BOUNDARY SHOULD CONTINUE A SLOW SOUTHWARD PROGRESSION THROUGH THE REST OF THE AFTERNOON AND EVENING. WEAK VORT LOBES ALOFT WILL CONTINUE TO TRAVERSE ALONG THE SURFACE BOUNDARY AND WARRANT AT LEAST MAINTAINING A LOW CHANCE POPS ACROSS EXTREME SOUTHERN PORTIONS OF THE FORECAST AREA THROUGH THE EVENING. HRRR ALSO CONTINUES TO HINT AT WEAK AND WIDELY SCATTERED DEVELOPMENT IN THE VICINITY OF THE BOUNDARY INTO THE EVENING. FURTHER NORTH...RAIN HAS ENDED WITH DRIER AIR ADVECTING INTO THE REGION. REVISITING POTENTIAL FOR LOW STRATUS AND FOG TO REDEVELOP LATER TONIGHT AS DIURNAL CU THAT DEVELOPS THIS AFTERNOON DIMINISHES...AND REMNANT CLOUD COVER AND MOISTURE EXPAND BACK NORTH. SOME UNCERTAINTY WITH RESPECT TO COVERAGE OF BOTH STRATUS AND FOG...BUT CURRENT THINKING AT THIS TIME IS THAT FOG MAY BE GREATER CONCERN OVER THE NORTH AND WEST WHERE SKIES HAD CLEARED TO SOME DEGREE...WHILE POINTS FURTHER SOUTH AND EAST LIKELY DEAL WITH LOW CLOUDS OVERNIGHT. MODEL SOUNDINGS HINTING AT A SHALLOW INVERSION DEVELOPING AS WELL. HAVE MAINTAINED MOSTLY CLOUDY SKIES FOR ALL BUT THE NORTHERN WABASH VALLEY AND INSERTED PATCHY FOG FOR THE ENTIRE FORECAST AREA. COULD CERTAINLY SEE LOCALIZED POCKETS OF DENSE FOG CONSIDERING AMOUNT OF MOISTURE LEFTOVER ALONG WITH LIGHT WINDS. TEMPS...TRENDED TOWARDS WARMER MAVMOS OVERNIGHT FOR LOWS... ESPECIALLY WITH UNCERTAINTY REGARDING STRATUS COVERAGE AND FOG POTENTIAL. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... ISSUED AT 244 PM EDT THU SEP 27 2012 FORECAST CHALLENGES FOCUS ON CLOUDS AND TEMPS AS A STRONG UPPER LEVEL LOW DROPS SOUTH FROM JAMES BAY AND INTO THE EASTERN GREAT LAKES OVER THE WEEKEND. MODEL SOUNDINGS AND RH PROGS INDICATING SOME FORM OF STRATUS REMAINING ACROSS PORTIONS OF THE FORECAST AREA WELL INTO THE MORNING. PRESENCE OF A LOW LEVEL THERMAL TROUGH AND CONVECTIVE TEMPS IN THE 60S SHOULD ENSURE THAT THE LEFTOVER STRATUS WILL MIX OUT INTO A FAIRLY WELL DEVELOPED CU FIELD FOR THE AFTERNOON AND WILL ROLL WITH PARTLY CLOUDY SKIES. SKIES WILL CLEAR FRIDAY EVENING WITH HIGH PRESSURE ACROSS THE REGION...BUT ANTICIPATE SOME MID LEVEL CLOUDS EXPANDING BACK ACROSS CENTRAL INDIANA LATE FRIDAY NIGHT AND INTO SATURDAY MORNING AS A SHORTWAVE ALOFT PASSES THROUGH. THE PASSAGE OF THE SHORTWAVE WILL SIGNAL THE BEGINNING OF A DEEPENING AND SOUTHWARD TREK TO AN UPPER LOW SOUTH FROM JAMES BAY. THE UPPER LOW WILL DIVE THROUGH THE EASTERN GREAT LAKES SATURDAY NIGHT AND SUNDAY AND SERVE TO SHARPEN THE UPPER LEVEL TROUGHING AND CYCLONIC FLOW ALOFT OVER MUCH OF THE OHIO VALLEY. WHILE CENTRAL INDIANA WILL NOT BE DIRECTLY IMPACTED FROM THE UPPER LOW WITH THE MORE SIGNIFICANT FORCING ALOFT REMAINING TO THE NORTHEAST...THE RELATIVE PROXIMITY OF THE UPPER LOW WILL BRING A RENEWED SURGE OF COOLER AIR AND SOME CLOUDS THROUGH MIDDAY SUNDAY. SKIES WILL CLEAR BY LATE DAY SUNDAY AS THE FEATURE PULLS AWAY TO THE EAST AND HIGH PRESSURE REASSERTS A STRONGER INFLUENCE OVER THE REGION. TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE FOR TEMPERATURES FRIDAY THROUGH SUNDAY CONSIDERING 850MB TEMPS AND LOW LEVEL THERMAL TECHNIQUES. COOLEST DAY SHOULD BE SUNDAY AS PRESENCE OF LOW LEVEL COLD ADVECTION ON THE BACK SIDE OF THE UPPER LOW WILL KEEP MUCH OF THE FORECAST AREA IN THE 60S. LEANED TOWARDS METMOS FOR LOWS AS IT APPEARS TO CAPTURE THE VARIANCE IN TEMPS IN RURAL AREAS BETTER. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... ISSUED AT 227 PM EDT THU SEP 27 2012 LONG TERM PERIOD WILL BE DOMINATED BY SURFACE HIGH PRESSURE AND ZONAL TO WEAKLY CYCLONIC FLOW. ONLY REAL OPPORTUNITY FOR PRECIPITATION APPEARS TO BE VERY LATE IN THE PERIOD AS MODELS BRING A SLUG OF TROPICAL MOISTURE NORTH FROM THE GULF COAST LATE IN THE WEEK. IT IS ONLY IN THE AREA BRIEFLY BEFORE BEING QUICKLY PULLED NORTHEAST. LOW POPS PROVIDED BY ALLBLEND APPEARED REASONABLE AND DID NOT CHANGE SIGNIFICANTLY. TEMPERATURES FROM INITIALIZATION APPEARED SLIGHTLY COOL BASED ON 850 TEMPS FROM GFS/EURO. RAISED HIGHS A DEGREE ACROSS THE BOARD. LOWS LOOKED FINE. && .AVIATION /DISCUSSION FOR THE 280000Z TAF ISSUANCE/... ISSUED AT 655 PM EDT THU SEP 27 2012 IFR CONDITIONS LIKELY AGAIN LATE TONIGHT AND EARLY FRIDAY. HIGH PRESSURE BUILDING INTO THE GREAT LAKES WAS PRODUCING A VERY LIGHT NORTH TO NORTHEAST FLOW. DRIER AIR WAS POISED TO OUR NORTHWEST. BUT DEWPOINTS WERE STILL IN THE UPPER 50S TO MIDDLE 60S ACROSS CENTRAL INDIANA. WITH VERY LIGHT WINDS AND A MOIST GROUND DO NOT EXPECT DEWPOINTS TO DROP ENOUGH TO PRECLUDE STRATUS/FOG. ONE POSSIBLE EXCEPTION MIGHT BE KLAF...SO WILL BE SLIGHTLY MORE OPTIMISTIC THERE. KBMG ON OTHER HAND MAY DROP TO LIFR CONDITIONS OVERNIGHT. ON FRIDAY...STRATUS/FOG WILL LIFT BY MID TO LATE MORNING. CONVECTIVE TEMPERATURES WILL BE IN UPPER 60S...SO EXPECT MOSTLY BROKEN 4 TO 5 THOUSAND CLOUDS MIDDAY ON WITH SOME CLEARING TOWARDS END OF THE TAF PERIOD. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....NIELD AVIATION...JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
428 PM EDT THU SEP 27 2012 .UPDATE... AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 244 PM EDT THU SEP 27 2012 A FRONTAL BOUNDARY WILL SLOWLY SAG SOUTH OF THE OHIO RIVER BY EARLY FRIDAY AND BE REPLACED BY HIGH PRESSURE...BRINGING DRIER WEATHER AND MORE SUNSHINE FOR FRIDAY. A SHARP UPPER LEVEL DISTURBANCE WILL DROP THROUGH THE EASTERN GREAT LAKES OVER THE WEEKEND...USHERING IN A COOLER AIRMASS BY SUNDAY. HIGH PRESSURE AND RIDGING ALOFT WILL PROVIDE FOR DRY WEATHER WITH A WARMING TREND THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TONIGHT/... ISSUED AT 244 PM EDT THU SEP 27 2012 BASED ON OBSERVATIONS AT 18Z...FRONTAL BOUNDARY APPEARS TO BE LOCATED OVER FAR SOUTHEAST SECTIONS OF THE FORECAST AREA. SKIES HAVE SLOWLY CLEARED OVER THE NORTHERN HALF OF THE FORECAST AREA SO FAR THIS AFTERNOON AS DRIER AIR NUDGES INTO THE REGION. HOWEVER AS CONVECTIVE TEMPS ARE REACHED...AREAS ARE FILLING BACK IN WITH CU. TEMPS WERE MAINLY IN THE 60S...ALTHOUGH A FEW LOCATIONS OVER THE WABASH VALLEY HAD WARMED INTO THE 70S WHERE THE MOST SUNSHINE HAD BEEN EXPERIENCED SO FAR. THE FRONTAL BOUNDARY SHOULD CONTINUE A SLOW SOUTHWARD PROGRESSION THROUGH THE REST OF THE AFTERNOON AND EVENING. WEAK VORT LOBES ALOFT WILL CONTINUE TO TRAVERSE ALONG THE SURFACE BOUNDARY AND WARRANT AT LEAST MAINTAINING A LOW CHANCE POPS ACROSS EXTREME SOUTHERN PORTIONS OF THE FORECAST AREA THROUGH THE EVENING. HRRR ALSO CONTINUES TO HINT AT WEAK AND WIDELY SCATTERED DEVELOPMENT IN THE VICINITY OF THE BOUNDARY INTO THE EVENING. FURTHER NORTH...RAIN HAS ENDED WITH DRIER AIR ADVECTING INTO THE REGION. REVISITING POTENTIAL FOR LOW STRATUS AND FOG TO REDEVELOP LATER TONIGHT AS DIURNAL CU THAT DEVELOPS THIS AFTERNOON DIMINISHES...AND REMNANT CLOUD COVER AND MOISTURE EXPAND BACK NORTH. SOME UNCERTAINTY WITH RESPECT TO COVERAGE OF BOTH STRATUS AND FOG...BUT CURRENT THINKING AT THIS TIME IS THAT FOG MAY BE GREATER CONCERN OVER THE NORTH AND WEST WHERE SKIES HAD CLEARED TO SOME DEGREE...WHILE POINTS FURTHER SOUTH AND EAST LIKELY DEAL WITH LOW CLOUDS OVERNIGHT. MODEL SOUNDINGS HINTING AT A SHALLOW INVERSION DEVELOPING AS WELL. HAVE MAINTAINED MOSTLY CLOUDY SKIES FOR ALL BUT THE NORTHERN WABASH VALLEY AND INSERTED PATCHY FOG FOR THE ENTIRE FORECAST AREA. COULD CERTAINLY SEE LOCALIZED POCKETS OF DENSE FOG CONSIDERING AMOUNT OF MOISTURE LEFTOVER ALONG WITH LIGHT WINDS. TEMPS...TRENDED TOWARDS WARMER MAVMOS OVERNIGHT FOR LOWS... ESPECIALLY WITH UNCERTAINTY REGARDING STRATUS COVERAGE AND FOG POTENTIAL. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... ISSUED AT 244 PM EDT THU SEP 27 2012 FORECAST CHALLENGES FOCUS ON CLOUDS AND TEMPS AS A STRONG UPPER LEVEL LOW DROPS SOUTH FROM JAMES BAY AND INTO THE EASTERN GREAT LAKES OVER THE WEEKEND. MODEL SOUNDINGS AND RH PROGS INDICATING SOME FORM OF STRATUS REMAINING ACROSS PORTIONS OF THE FORECAST AREA WELL INTO THE MORNING. PRESENCE OF A LOW LEVEL THERMAL TROUGH AND CONVECTIVE TEMPS IN THE 60S SHOULD ENSURE THAT THE LEFTOVER STRATUS WILL MIX OUT INTO A FAIRLY WELL DEVELOPED CU FIELD FOR THE AFTERNOON AND WILL ROLL WITH PARTLY CLOUDY SKIES. SKIES WILL CLEAR FRIDAY EVENING WITH HIGH PRESSURE ACROSS THE REGION...BUT ANTICIPATE SOME MID LEVEL CLOUDS EXPANDING BACK ACROSS CENTRAL INDIANA LATE FRIDAY NIGHT AND INTO SATURDAY MORNING AS A SHORTWAVE ALOFT PASSES THROUGH. THE PASSAGE OF THE SHORTWAVE WILL SIGNAL THE BEGINNING OF A DEEPENING AND SOUTHWARD TREK TO AN UPPER LOW SOUTH FROM JAMES BAY. THE UPPER LOW WILL DIVE THROUGH THE EASTERN GREAT LAKES SATURDAY NIGHT AND SUNDAY AND SERVE TO SHARPEN THE UPPER LEVEL TROUGHING AND CYCLONIC FLOW ALOFT OVER MUCH OF THE OHIO VALLEY. WHILE CENTRAL INDIANA WILL NOT BE DIRECTLY IMPACTED FROM THE UPPER LOW WITH THE MORE SIGNIFICANT FORCING ALOFT REMAINING TO THE NORTHEAST...THE RELATIVE PROXIMITY OF THE UPPER LOW WILL BRING A RENEWED SURGE OF COOLER AIR AND SOME CLOUDS THROUGH MIDDAY SUNDAY. SKIES WILL CLEAR BY LATE DAY SUNDAY AS THE FEATURE PULLS AWAY TO THE EAST AND HIGH PRESSURE REASSERTS A STRONGER INFLUENCE OVER THE REGION. TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE FOR TEMPERATURES FRIDAY THROUGH SUNDAY CONSIDERING 850MB TEMPS AND LOW LEVEL THERMAL TECHNIQUES. COOLEST DAY SHOULD BE SUNDAY AS PRESENCE OF LOW LEVEL COLD ADVECTION ON THE BACK SIDE OF THE UPPER LOW WILL KEEP MUCH OF THE FORECAST AREA IN THE 60S. LEANED TOWARDS METMOS FOR LOWS AS IT APPEARS TO CAPTURE THE VARIANCE IN TEMPS IN RURAL AREAS BETTER. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... ISSUED AT 227 PM EDT THU SEP 27 2012 LONG TERM PERIOD WILL BE DOMINATED BY SURFACE HIGH PRESSURE AND ZONAL TO WEAKLY CYCLONIC FLOW. ONLY REAL OPPORTUNITY FOR PRECIPITATION APPEARS TO BE VERY LATE IN THE PERIOD AS MODELS BRING A SLUG OF TROPICAL MOISTURE NORTH FROM THE GULF COAST LATE IN THE WEEK. IT IS ONLY IN THE AREA BRIEFLY BEFORE BEING QUICKLY PULLED NORTHEAST. LOW POPS PROVIDED BY ALLBLEND APPEARED REASONABLE AND DID NOT CHANGE SIGNIFICANTLY. TEMPERATURES FROM INITIALIZATION APPEARED SLIGHTLY COOL BASED ON 850 TEMPS FROM GFS/EURO. RAISED HIGHS A DEGREE ACROSS THE BOARD. LOWS LOOKED FINE. && .AVIATION /DISCUSSION FOR THE 27/21Z KIND TAF UPDATE/... ISSUED AT 428 PM EDT THU SEP 27 2012 MINOR TWEAKS MADE TO KIND TAF PER OBSERVATIONS. NO OTHER CHANGES NEEDED AT THIS TIME. PREVIOUS AVIATION DISCUSSION FOLLOWS... RESTRICTIONS LIKELY FOR A SIGNIFICANT PORTION OF THE TAF PERIOD AT MOST SITES. IFR SHOULD CONTINUE INTO MID AFTERNOON AT IND/BMG...WITH CONDITIONS HAVING QUICKLY IMPROVED AT LAF/BMG EARLY THIS AFTERNOON. APPEARS FROM FORECAST SOUNDINGS THAT LOW CLOUD WILL LIFT AND SCOUR OUT EARLY THIS EVENING WITH ONLY SOME MID CLOUD IN THE AREA...BUT OVERNIGHT...EXPECT THAT COOLING AIR AND REMAINING LOW LEVEL MOISTURE WILL COMBINE TO ONCE AGAIN BRING IFR CONDITIONS TO THE SITES...PERHAPS EVEN LIFR OR WORSE. FOR NOW...WILL INCLUDE 1-3SM BR AND BKN005-007 AFTER 04-08Z. WINDS WILL BE BELOW 10KT THROUGH THE PERIOD...VARIABLE AT TIMES BUT GENERALLY OUT OF THE NORTH NORTHEAST. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....NIELD AVIATION...NIELD/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
244 PM EDT THU SEP 27 2012 .UPDATE... THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 244 PM EDT THU SEP 27 2012 A FRONTAL BOUNDARY WILL SLOWLY SAG SOUTH OF THE OHIO RIVER BY EARLY FRIDAY AND BE REPLACED BY HIGH PRESSURE...BRINGING DRIER WEATHER AND MORE SUNSHINE FOR FRIDAY. A SHARP UPPER LEVEL DISTURBANCE WILL DROP THROUGH THE EASTERN GREAT LAKES OVER THE WEEKEND...USHERING IN A COOLER AIRMASS BY SUNDAY. HIGH PRESSURE AND RIDGING ALOFT WILL PROVIDE FOR DRY WEATHER WITH A WARMING TREND THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /TONIGHT/... ISSUED AT 244 PM EDT THU SEP 27 2012 BASED ON OBSERVATIONS AT 18Z...FRONTAL BOUNDARY APPEARS TO BE LOCATED OVER FAR SOUTHEAST SECTIONS OF THE FORECAST AREA. SKIES HAVE SLOWLY CLEARED OVER THE NORTHERN HALF OF THE FORECAST AREA SO FAR THIS AFTERNOON AS DRIER AIR NUDGES INTO THE REGION. HOWEVER AS CONVECTIVE TEMPS ARE REACHED...AREAS ARE FILLING BACK IN WITH CU. TEMPS WERE MAINLY IN THE 60S...ALTHOUGH A FEW LOCATIONS OVER THE WABASH VALLEY HAD WARMED INTO THE 70S WHERE THE MOST SUNSHINE HAD BEEN EXPERIENCED SO FAR. THE FRONTAL BOUNDARY SHOULD CONTINUE A SLOW SOUTHWARD PROGRESSION THROUGH THE REST OF THE AFTERNOON AND EVENING. WEAK VORT LOBES ALOFT WILL CONTINUE TO TRAVERSE ALONG THE SURFACE BOUNDARY AND WARRANT AT LEAST MAINTAINING A LOW CHANCE POPS ACROSS EXTREME SOUTHERN PORTIONS OF THE FORECAST AREA THROUGH THE EVENING. HRRR ALSO CONTINUES TO HINT AT WEAK AND WIDELY SCATTERED DEVELOPMENT IN THE VICINITY OF THE BOUNDARY INTO THE EVENING. FURTHER NORTH...RAIN HAS ENDED WITH DRIER AIR ADVECTING INTO THE REGION. REVISITING POTENTIAL FOR LOW STRATUS AND FOG TO REDEVELOP LATER TONIGHT AS DIURNAL CU THAT DEVELOPS THIS AFTERNOON DIMINISHES...AND REMNANT CLOUD COVER AND MOISTURE EXPAND BACK NORTH. SOME UNCERTAINTY WITH RESPECT TO COVERAGE OF BOTH STRATUS AND FOG...BUT CURRENT THINKING AT THIS TIME IS THAT FOG MAY BE GREATER CONCERN OVER THE NORTH AND WEST WHERE SKIES HAD CLEARED TO SOME DEGREE...WHILE POINTS FURTHER SOUTH AND EAST LIKELY DEAL WITH LOW CLOUDS OVERNIGHT. MODEL SOUNDINGS HINTING AT A SHALLOW INVERSION DEVELOPING AS WELL. HAVE MAINTAINED MOSTLY CLOUDY SKIES FOR ALL BUT THE NORTHERN WABASH VALLEY AND INSERTED PATCHY FOG FOR THE ENTIRE FORECAST AREA. COULD CERTAINLY SEE LOCALIZED POCKETS OF DENSE FOG CONSIDERING AMOUNT OF MOISTURE LEFTOVER ALONG WITH LIGHT WINDS. TEMPS...TRENDED TOWARDS WARMER MAVMOS OVERNIGHT FOR LOWS... ESPECIALLY WITH UNCERTAINTY REGARDING STRATUS COVERAGE AND FOG POTENTIAL. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... ISSUED AT 244 PM EDT THU SEP 27 2012 FORECAST CHALLENGES FOCUS ON CLOUDS AND TEMPS AS A STRONG UPPER LEVEL LOW DROPS SOUTH FROM JAMES BAY AND INTO THE EASTERN GREAT LAKES OVER THE WEEKEND. MODEL SOUNDINGS AND RH PROGS INDICATING SOME FORM OF STRATUS REMAINING ACROSS PORTIONS OF THE FORECAST AREA WELL INTO THE MORNING. PRESENCE OF A LOW LEVEL THERMAL TROUGH AND CONVECTIVE TEMPS IN THE 60S SHOULD ENSURE THAT THE LEFTOVER STRATUS WILL MIX OUT INTO A FAIRLY WELL DEVELOPED CU FIELD FOR THE AFTERNOON AND WILL ROLL WITH PARTLY CLOUDY SKIES. SKIES WILL CLEAR FRIDAY EVENING WITH HIGH PRESSURE ACROSS THE REGION...BUT ANTICIPATE SOME MID LEVEL CLOUDS EXPANDING BACK ACROSS CENTRAL INDIANA LATE FRIDAY NIGHT AND INTO SATURDAY MORNING AS A SHORTWAVE ALOFT PASSES THROUGH. THE PASSAGE OF THE SHORTWAVE WILL SIGNAL THE BEGINNING OF A DEEPENING AND SOUTHWARD TREK TO AN UPPER LOW SOUTH FROM JAMES BAY. THE UPPER LOW WILL DIVE THROUGH THE EASTERN GREAT LAKES SATURDAY NIGHT AND SUNDAY AND SERVE TO SHARPEN THE UPPER LEVEL TROUGHING AND CYCLONIC FLOW ALOFT OVER MUCH OF THE OHIO VALLEY. WHILE CENTRAL INDIANA WILL NOT BE DIRECTLY IMPACTED FROM THE UPPER LOW WITH THE MORE SIGNIFICANT FORCING ALOFT REMAINING TO THE NORTHEAST...THE RELATIVE PROXIMITY OF THE UPPER LOW WILL BRING A RENEWED SURGE OF COOLER AIR AND SOME CLOUDS THROUGH MIDDAY SUNDAY. SKIES WILL CLEAR BY LATE DAY SUNDAY AS THE FEATURE PULLS AWAY TO THE EAST AND HIGH PRESSURE REASSERTS A STRONGER INFLUENCE OVER THE REGION. TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE FOR TEMPERATURES FRIDAY THROUGH SUNDAY CONSIDERING 850MB TEMPS AND LOW LEVEL THERMAL TECHNIQUES. COOLEST DAY SHOULD BE SUNDAY AS PRESENCE OF LOW LEVEL COLD ADVECTION ON THE BACK SIDE OF THE UPPER LOW WILL KEEP MUCH OF THE FORECAST AREA IN THE 60S. LEANED TOWARDS METMOS FOR LOWS AS IT APPEARS TO CAPTURE THE VARIANCE IN TEMPS IN RURAL AREAS BETTER. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... ISSUED AT 227 PM EDT THU SEP 27 2012 LONG TERM PERIOD WILL BE DOMINATED BY SURFACE HIGH PRESSURE AND ZONAL TO WEAKLY CYCLONIC FLOW. ONLY REAL OPPORTUNITY FOR PRECIPITATION APPEARS TO BE VERY LATE IN THE PERIOD AS MODELS BRING A SLUG OF TROPICAL MOISTURE NORTH FROM THE GULF COAST LATE IN THE WEEK. IT IS ONLY IN THE AREA BRIEFLY BEFORE BEING QUICKLY PULLED NORTHEAST. LOW POPS PROVIDED BY ALLBLEND APPEARED REASONABLE AND DID NOT CHANGE SIGNIFICANTLY. TEMPERATURES FROM INITIALIZATION APPEARED SLIGHTLY COOL BASED ON 850 TEMPS FROM GFS/EURO. RAISED HIGHS A DEGREE ACROSS THE BOARD. LOWS LOOKED FINE. && .AVIATION /DISCUSSION FOR THE 27/18Z TAFS/... ISSUED AT 116 PM EDT THU SEP 27 2012 RESTRICTIONS LIKELY FOR A SIGNIFICANT PORTION OF THE TAF PERIOD AT MOST SITES. IFR SHOULD CONTINUE INTO MID AFTERNOON AT IND/BMG...WITH CONDITIONS HAVING QUICKLY IMPROVED AT LAF/BMG EARLY THIS AFTERNOON. APPEARS FROM FORECAST SOUNDINGS THAT LOW CLOUD WILL LIFT AND SCOUR OUT EARLY THIS EVENING WITH ONLY SOME MID CLOUD IN THE AREA...BUT OVERNIGHT...EXPECT THAT COOLING AIR AND REMAINING LOW LEVEL MOISTURE WILL COMBINE TO ONCE AGAIN BRING IFR CONDITIONS TO THE SITES...PERHAPS EVEN LIFR OR WORSE. FOR NOW...WILL INCLUDE 1-3SM BR AND BKN005-007 AFTER 04-08Z. WINDS WILL BE BELOW 10KT THROUGH THE PERIOD...VARIABLE AT TIMES BUT GENERALLY OUT OF THE NORTH NORTHEAST. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...RYAN SHORT TERM...RYAN LONG TERM....NIELD AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
128 PM EDT THU SEP 27 2012 .AVIATION... NORTHEASTERLY FLOW OFF THE GREAT LAKES IS HELPING TO MAINTAIN A FAIR AMOUNT OF LOW LEVEL MOISTURE BEHIND THE EXITING FRONTAL BOUNDARY. THIS WILL LEAD TO LOW END VFR CONDITIONS FOR THE REST OF THE DAY. LATEST FORECAST SOUNDINGS SUGGEST THIS MOISTURE WILL REMAIN IN PLACE THROUGH TOMORROW. LEFT CEILINGS IN VFR CATEGORY FOR NOW BUT MVFR CONDITIONS ARE POSSIBLE OVERNIGHT WITH LIGHT NORTHEASTERLY WINDS. && .PREV DISCUSSION... /ISSUED 503 AM EDT THU SEP 27 2012/ SHORT TERM... TODAY THROUGH FRIDAY NIGHT. PRIMARY CONCERN WRT OH VLY FRONTAL WAVE STRENGTH/POSITIONING AND POTNL FOR SHRA TO SKIRT FAR SERN CWA LATER THIS AM. 27/00 UTC NAM APPEARS TOO STRONG/NORTH WITH AFOREMENTIONED WAVE...AS SUCH WL DISCOUNT/SUBJECTIVELY WEAKEN AND SHUNT SWD IN LIGHT OF MID TROPOSPHERIC SPEED MAX ALONG OH RVR PER TCVG/KILN VWP AND CENTROID OF SFC PRES FALLS ACRS ERN KY. INITIAL 5H ZONAL CONFLUENCY WITH LOWER TROP FLOW WELL VEERED/STRENGTHENED SFC-4KFT PER KIND/KIWX VWP DENOTING DRYING/SUBSIDENT AIRMASS ESTABLISHING FIRM FOOTHOLD THROUGH ENTIRE SRN GRTLKS RGN AND INTO NRN EXTENT OF OH VLY...BODING UNFAVORABLE FOR A SHARP NWD GENUFLECTION OF CURRENT I70 CORRIDOR SHRA. 06 UTC NAM AND LATEST RAP RUNS APPEAR MORE REASONABLE IN STRENGTH/POSITIONING...WL CONT WITH DRY FORECAST TDY AND MONITOR TRENDS THROUGH AM HOURS...AS HIGH END CHC/LOW LKLY 00 UTC GUID POPS CREATING APPREHENSION. BY DY2 DEEP JAMES BAY/LWR GRTLKS TROFING DOMINATES WITH ARDENT NRN PLAINS RIDGING LEADING TO DOWNSTREAM REXED CUT OFF...WITH CRISP/COOL/DRY FALL AIRMASS. ONLY MINOR TWEAKS TO TEMPS/DPS REQRD. LONG TERM... SATURDAY THROUGH WEDNESDAY...THE FORECAST CHALLENGES EARLY INCLUDE THE DEVELOPMENT OF A CUT OFF LOW DOWNSTREAM OF A TEMPORARY BLOCKING RIDGE. PREFER THE RECENT PERFORMANCE OF THE ECMWF AND THE CURRENT HANDLING OF ECMWF WITH THIS SYSTEM. KEPT THE FORECAST DRY AS ISENTROPIC LEVELS INDICATE LIMITED MOISTURE AVAILABLE FOR THIS SYSTEM. ALSO...THE BEST LIFT SHOULD REMAIN NORTHEAST OF THE FORECAST AREA IN THE DEFORMATION ZONE. KEPT TEMPERATURES COOL SUNDAY...WITH MODERATING TEMPERATURES THROUGH THE END OF THE PERIOD. LOWERED LOW TEMPERATURES SUNDAY NIGHT GIVEN CLEARING SKIES...LIGHT WINDS...AND A COOL AND DRY AIRMASS...IDEAL CONDITIONS FOR A SHALLOW RADIATION INVERSION TO FORM. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...RIP CURRENT RISK UNTIL 4 PM CDT THIS AFTERNOON FOR INZ003. MI...RIP CURRENT RISK UNTIL 5 PM EDT THIS AFTERNOON FOR MIZ077. OH...NONE. LM...NONE. && $$ SHORT TERM...MURPHY LONG TERM...SKIPPER AVIATION...AGD
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
503 AM EDT THU SEP 27 2012 .SHORT TERM... TODAY THROUGH FRIDAY NIGHT. PRIMARY CONCERN WRT OH VLY FRONTAL WAVE STRENGTH/POSITIONING AND POTNL FOR SHRA TO SKIRT FAR SERN CWA LATER THIS AM. 27/00 UTC NAM APPEARS TOO STRONG/NORTH WITH AFOREMENTIONED WAVE...AS SUCH WL DISCOUNT/SUBJECTIVELY WEAKEN AND SHUNT SWD IN LIGHT OF MID TROPOSPHERIC SPEED MAX ALONG OH RVR PER TCVG/KILN VWP AND CENTROID OF SFC PRES FALLS ACRS ERN KY. INITIAL 5H ZONAL CONFLUENCY WITH LOWER TROP FLOW WELL VEERED/STRENGTHENED SFC-4KFT PER KIND/KIWX VWP DENOTING DRYING/SUBSIDENT AIRMASS ESTABLISHING FIRM FOOTHOLD THROUGH ENTIRE SRN GRTLKS RGN AND INTO NRN EXTENT OF OH VLY...BODING UNFAVORABLE FOR A SHARP NWD GENUFLECTION OF CURRENT I70 CORRIDOR SHRA. 06 UTC NAM AND LATEST RAP RUNS APPEAR MORE REASONABLE IN STRENGTH/POSITIONING...WL CONT WITH DRY FORECAST TDY AND MONITOR TRENDS THROUGH AM HOURS...AS HIGH END CHC/LOW LKLY 00 UTC GUID POPS CREATING APPREHENSION. BY DY2 DEEP JAMES BAY/LWR GRTLKS TROFING DOMINATES WITH ARDENT NRN PLAINS RIDGING LEADING TO DOWNSTREAM REXED CUT OFF...WITH CRISP/COOL/DRY FALL AIRMASS. ONLY MINOR TWEAKS TO TEMPS/DPS REQRD. && .LONG TERM... SATURDAY THROUGH WEDNESDAY...THE FORECAST CHALLENGES EARLY INCLUDE THE DEVELOPMENT OF A CUT OFF LOW DOWNSTREAM OF A TEMPORARY BLOCKING RIDGE. PREFER THE RECENT PERFORMANCE OF THE ECMWF AND THE CURRENT HANDLING OF ECMWF WITH THIS SYSTEM. KEPT THE FORECAST DRY AS ISENTROPIC LEVELS INDICATE LIMITED MOISTURE AVAILABLE FOR THIS SYSTEM. ALSO...THE BEST LIFT SHOULD REMAIN NORTHEAST OF THE FORECAST AREA IN THE DEFORMATION ZONE. KEPT TEMPERATURES COOL SUNDAY...WITH MODERATING TEMPERATURES THROUGH THE END OF THE PERIOD. LOWERED LOW TEMPERATURES SUNDAY NIGHT GIVEN CLEARING SKIES...LIGHT WINDS...AND A COOL AND DRY AIRMASS...IDEAL CONDITIONS FOR A SHALLOW RADIATION INVERSION TO FORM. && .AVIATION... /06 UTC TAFS/ PRIMARILY VFR THRU THE FCST PD AS DRY SUBSIDENT AIRMASS CONTINUES TO DEEPEN ACRS NRN IN. NAM/RAP POINT SNDGS SUGGEST SIG DEGREE OF RESIDUAL MOISTURE REMAINING WITHIN 950-900MB LYR AT KFWA WHICH MAY PROVIDE CATALYST FOR MVFR CU FIELD AS SHALLOW CONVECTIVE OVERTURN COMMENCES/DEEPENS WITHIN 1-2 HRS AFTER SUNRISE. EXPECT ANY MVFR CIGS TO BE SHORTLIVED AND AOA FUEL ALT...BEFORE RISING ABOVE 3KFT/SPREADING OUT AT BASE OF SUBSIDENCE INVERSION...PER CONVECTIVE CLOUD BASE/HGHT DIAGRAM. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...RIP CURRENT RISK UNTIL 7 AM CDT THIS MORNING FOR INZ003. MI...RIP CURRENT RISK UNTIL 8 AM EDT THIS MORNING FOR MIZ077. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LMZ043-046. && $$ SHORT TERM...MURPHY LONG TERM...SKIPPER AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
345 PM CDT THU SEP 27 2012 ...UPDATE TO LONG TERM DISCUSSION... .SYNOPSIS... ISSUED AT 237 PM CDT THU SEP 27 2012 AT THE JET STREAM LEVEL OF 250MB, THERE WAS A 70 TO 80 KNOT JET OVER EASTERN ARIZONA EXTENDING TO NORTHEASTERN NEW MEXICO, WITH A NORTHEAST DIRECTION TOWARD SOUTHWEST KANSAS. ANOTHER 70 KNOT JET WAS FROM NORTH OF KANSAS CITY EAST-SOUTHEASTWARD TO SOUTHERN ILLINOIS. THERE WAS ALSO A WEAK EASTERLY JET IN THE 70 KNOT RANGE OVER ONTARIO, WITH YET ANOTHER 90 TO 100KT JET ENTERING EXTREME NORTHWESTERN NORTH AMERICA OVER THE NORTHWESTERN BRITISH COLUMBIA PROVIDENCE. THE 500MB CHART SHOWED A TROUGH FROM EASTERN MONTANA SOUTH INTO SOUTHWESTERN NEW MEXICO. A LOW PRESSURE AREA WAS OVER NORTHERN COLORADO, WITH A TROUGH EXTENDING EASTWARD OVER NORTHERN COLORADO INTO NORTH CENTRAL KANSAS. A LARGE MOISTURE FIELD RAN FROM WESTERN TEXAS NORTH THROUGH THE TEXAS AND OKLAHOMA BORDER, THEN TURNED EAST INTO SOUTHWESTERN MISSOURI. THE 700MB ANALYSIS SHOWED ONE TROUGH FROM SOUTHEASTERN KANSAS THROUGH CENTRAL OKLAHOMA INTO THE NORTHWESTERN TEXAS PANHANDLE. ANOTHER TROUGH WAS FROM NORTHWESTERN NORTH DAKOTA SOUTH TO A LOW PRESSURE AREA OVER NORTHERN COLORADO, TO NORTHWESTERN NEW MEXICO. THERE WAS A COOL POCKET OF +04C AIR OVER SOUTHERN WISCONSIN. A LARGE MOISTURE FIELD WITH DEW POINT DEPRESSIONS LESS THAN 5C WAS FROM EXTREME SOUTHWESTERN IDAHO SOUTHEAST TOWARD NORTHWESTERN ARKANSAS. THE 700MB TEMP/WINDS AT DDC WERE +03C/30010KTS. DOWN AT THE 850MB CHART, A LOW PRESSURE AREA OVER NORTHEASTERN COLORADO HAD A FRONT EXTENDING TO THE SOUTHEAST DIRECTION TO THE EASTERN TEXAS PANHANDLE, SWOOPING SOUTHEAST THROUGH SOUTHERN OKLAHOMA, AND THEN BACK TO THE NORTHEAST INTO SOUTHERN ILLINOIS. A SLIGHT WARM POCKET OF AIR WAS LODGED OVER THE NORTHERN PLAINS IN NORTHWESTERN SOUTH DAKOTA WITH +18C TEMPS. ANOTHER COOL TONGUE OF AIR WAS FROM ONTARIO SOUTHWESTWARD TO EASTERN IOWA, WITH TEMPERATURES AS LOW AS -03C OVER THE NORTHEASTERN GREAT LAKES. THE 850MB TEMP/WINDS AT DDC WERE +14C/24007KT RESPECTFULLY. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 237 PM CDT THU SEP 27 2012 THE FIRST PRIORITY FOR THIS FORECAST IS THE CHANCE FOR SEVERE STORMS VERY LATE THIS AFTERNOON AND THIS EVENING. TEMPERATURES AND WINDS ARE OF A SECONDARY CONCERN. THE SPC DAY ONE OUTLOOK HAS OUR SOUTHWEST CORNER, SOUTHWEST OF A HAMILTON TO GRANT TO SEWARD LINE, IN A SLIGHT CHANCE. I THINK THERE COULD BE ONE OR TWO OR THREE HAIL PRODUCERS IN OUR WEST/SOUTHWEST CORNER, BUT MAINLY AFTER 9 PM CDT. THE HRRR MODEL HAS JUST MARGINAL CAPE THIS EVENING IN THE 1000 J/KG, THE RUC MODEL HAS LITTLE OR NO 0-6 KM HELICITY, AND FORECAST SOUNDINGS FROM BOTH THE HRRR AND RUC MODELS FOR A POINT NEAR RICHFIELD SHOW -5.8 LI`S BY 06Z. IF THERE IS SOME SEVERE, IT WILL BE A LATE SHOW AFTER 9PM CDT. WE HELD A EMS/KDOT/FEMA CONTACTS, AND TOLD THEM POSSIBLE HAILERS WITH UP TO GOLF BALL HAIL AFTER 7 PM CDT, SO THEY SHOULD HAVE PLENTY OF NOTICE. AFTER THE FIRST ROUND OF MARGINAL SEVERE CONVECTION, THERE IS A GOOD WAVE MOVING EAST ACROSS OUR CWA AFTER MIDNIGHT. THEREFORE, THERE WILL BE INCREASING POPS AFTER 06Z, FROM WEST TO EAST. THERE COULD BE A GOOD WIDESPREAD RAIN EVENT, BUT DID NOT OVERDO THE RAINFALL QPF SINCE HIGH RAINFALL AMOUNTS WILL SPOTTY SUCH AS THE LAST SEVERAL PRECIPITATION EVENTS. LAST NIGHT, DOWN NEAR LIBERAL, WE HAD ONE RAINFALL REPORT OF 3.50 INCHES 2 MILES SOUTH OF LIBERAL AND ANOTHER REPORT OF 2.61 INCHES OF RAIN FROM THE SOUTH-SOUTHWEST EDGE OF ROLLA. SO, WIDESPREAD RAIN LIKE THAT IS NOT EXPECTED AGAIN. THE RUC13 MODEL SOUNDING FOR NEAR ELKHART SHOWED 1.13 INCHES AT 06Z. OUR EASTERN CWA SHOULD STAY CLOUDY TONIGHT WITH 3-5SM FOG, AND THE WEST WILL LIKELY SEE EVEN LOWER LEVEL CLOUDS IN THE EASTERLY UPSLOPE FLOW. TEMPERATURES WILL NOT FALL QUICKLY UNDER THE THICK CLOUDS, AND SHOULD ONLY BOTTOM OUT IN THE MID 50S IN THE WEST AND THE LOWER 60S IN THE SOUTHEAST. FRIDAY COULD STILL BE WET WITH SCATTERED SHOWERS AND THUNDERSTORMS, WITH THE BETTER CHANCE IN OUR EASTERN COUNTIES EAST OF A LINE FROM HAYS TO DODGE CITY TO ASHLAND. THIS MAY BE AN EARLY MORNING THEN ANOTHER ROUND OF RAIN IN THE AFTERNOON EVENT. POPS WILL BE 40 TO 50 PERCENT EAST OF THAT LINE ABOVE, WITH 30 TO 40 POPS WEST OF THAT LINE. HOW MUCH RAIN IS ALWAYS THE QUESTION CALLERS SEEM TO ASK, BUT DO NOT THINK ANY ADDITIONAL HEAVY RAIN WILL FALL ON FRIDAY. THE UPPER SUPPORT WILL BE PULLING EAST DURING THE AFTERNOON, AND THE SURFACE FRONT SHOULD BE MOVING SOUTH OUT OF OUR CWA DURING THE AFTERNOON. LIGHT BUT STEADY UPSLOPE FLOW WILL BE THE MAIN SOURCE OF PRECIPITATION FRIDAY. FRIDAY AFTERNOON SHOULD BE ANOTHER COOL ONE, AS TEMPERATURES WILL STRUGGLE TO REACH THE MID 70S IN OUR EASTERN ZONES OF ELLIS, EDWARDS AND CLARK COUNTIES (AND EAST) AND IN THE LOWER 70S TO DOWN NEAR 70F DEGREES OUT WEST NEAR THE COLORADO BORDER NEAR THE STRONGEST UPSLOPE AFFECT. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 345 PM CDT THU SEP 27 2012 FRIDAY NIGHT: CONVECTION WILL QUICKLY BE ON THE WANE FRIDAY EVENING AS A 90 KT 250 HPA JET STREAK TRAVERSES QUICKLY ACROSS THE STATE AND AS DIURNAL INSTABILITY RAPIDLY DIMINISHES. AS A RESULT, HAVE RAMPED POPS DOWN SOONER ACROSS THE REGION BETWEEN FRIDAY EVENING AND TOWARDS MIDNIGHT SATURDAY. THE NEXT SENSIBLE WEATHER CONCERN HEADING INTO SATURDAY MORNING IS FOG. BUFKIT/BUFR FORECAST SOUNDINGS SHOW AN ENVIRONMENT THAT IS CONDUCIVE FOR RADIATIONAL FOG. THIS IS A RESULT OF HIGH PRESSURE BUILDING IN ACROSS KANSAS AND WINDS BECOMING LIGHT OR EVEN CALM. HAVE INSERTED AREAS OF FOG IN THE WX GRIDS AS BETTER CONFIDENCE OF FOG VIA THE AFOREMENTIONED SOUNDINGS AND PLAN VIEW RH PROGS IN THE BOUNDARY LAYER. SATURDAY THROUGH NEXT THURSDAY: THE FORECAST WILL BE FAIRLY DRY THROUGH MUCH OF THE PERIOD IN ASSOCIATION WITH UPPER LEVEL RIDGING, THE WARM PLUME SPREADING EAST, AND LACK OF REAL SURFACE MOISTURE & CONVERGENCE. THE EXCEPTION TO THIS IS SUNDAY EVENING. A SHORTWAVE TROUGH SKIRTING ACROSS THE NORTHERN PRAIRIES WILL USHER IN A COLD FRONT/TROF AXIS WHICH COULD BE THE IMPETUS FOR CONVECTION DURING THE AFTERNOON AND EARLY EVENING. WILL MAINLY USE THE 12Z ECMWF FOR GUIDANCE IN CONCERNING THIS CONVECTION FOR NOW. SLIGHT POPS LOOK REASONABLE FOR NOW AND RESULTED IN NOT MUCH CHANGE FROM THE PREVIOUS FORECAST. OTHERWISE, RELATIVELY HIGH 500 HPA HEIGHTS ARE EXPECTED ACROSS WESTERN KANSAS FOR MUCH OF NEXT WEEK. THE FLOW WILL BECOME MORE PERPENDICULAR TO THE ROCKIES BY MIDWEEK NEXT WEEK WHICH WILL RESULT IN LOWERING PRESSURES ACROSS THE LEE OF THE ROCKIES AND A CONTINUED WARM AIR ADVECTION PATTERN THROUGH THE LOWER ATMOSPHERE. AS A RESULT, EXPECT MODERATING TEMPERATURES THROUGH NEXT WEEK WITH NEAR TO ABOVE NORMAL HIGHS. THE 12Z ECMWF IS SHOWING A FAIRLY STRONG COLD FRONT TRAVERSING ACROSS THE KANSAS PRAIRIES BY NEXT THURSDAY. WILL NOT STRAY FROM WHAT THE ALLBLEND GIVES ME AS THE VALUES LOOK REASONABLE WITH HIGHS COOLING DOWN INTO THE 70S DEG F. UPPER LEVEL JET DYNAMICS WITH THIS FRONT LOOKS TO BE FAIRLY BROAD AND ELONGATED SO ANY SIGNIFICANT SYNOPTIC SCALE LIFT AND ASSOCIATED RESULTANT PRECIPITATION LOOKS TO REMAIN NORTH OF THE REGION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1150 AM CDT THU SEP 27 2012 FOR THIS AFTERNOON, EXPECT MVFR CIGS IN THE BKN-OVC025-030 RANGE AND VSBYS IN THE 5-6SM BR/HZ RANGE. THERE IS A SLIGHT CHANCE THROUGH 21Z ANY ONE TAF MAY DIP TO IFR CIGS IN THE BKN008 RANGE, BUT THOSE CIGS SHOULD BE SHORT LIVED. LIGHT WINDS EARLY WILL BECOME ESTABLISHED FROM THE EAST AT 10 TO 12 KNOTS THIS AFTERNOON. THERE IS ALSO A SLIGHT CHANCE FOR STRAY THUNDERSTORMS AFTER 22Z, ALONG WITH MVFR CIGS. LATER TONIGHT, CLOUDS AND FOG WILL ROLL BACK IN AFTER 06Z, GENERALLY IN THE MVFR CATER GORY FOR VSBYS IN 3-4SM BR. LOW STRATUS WILL BRING CIGS IN THE IFR CATEGORY, APPARENTLY IN THE OVC007 RANGE. && .PRELIMINARY POINT TEMPS/POPS... DDC 60 73 56 76 / 60 50 20 10 GCK 58 71 55 75 / 60 40 10 10 EHA 57 72 55 76 / 70 40 10 10 LBL 58 73 56 76 / 70 50 20 10 HYS 58 73 55 76 / 40 50 10 10 P28 62 75 60 77 / 60 60 20 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURKE SHORT TERM...BURKE LONG TERM...SUGDEN AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
319 PM CDT THU SEP 27 2012 .DISCUSSION... 20Z WATER VAPOR SHOW AN UPPER LEVEL DISTURBANCE SPINNING OVER NORTHERN CO. 500MB PROFILER DATA SUGGESTS A WEAK DISTURBANCE IS TRAVERSING THE STATE OVER A PRETTY GOOD DEWPOINT GRADIENT ACROSS EAST CENTRAL KS. MEANWHILE A SFC RIDGE OF HIGH PRESSURE EXTENDED FROM THE UPPER MIDWEST INTO THE CENTRAL PLAINS...HELPING TO CREATE THE DEWPOINT GRADIENT. FOR TONIGHT AND FRIDAY...THE MODELS HAVE BEEN IN REASONABLE AGREEMENT THAT A SLIGHTLY UNSTABLE ATMOSPHERE WITH WEAK FORCING WOULD PERSIST. WITH THE DEEPER MOISTURE PROGGED BY THE MODELS TO BE MAINLY ACROSS SOUTHERN KS...THINKING IS PRECIP CHANCES WILL BE BETTER TO THE SOUTH WITH SOME LOW POPS ACROSS EAST CENTRAL KS. THE CONVECTION THIS AFTERNOON APPEARS TO BE MAINLY DRIVEN BY THE WEAK DISTURBANCE AND DAYTIME HEATING ALONG THE DEWPOINT GRADIENT. AS THE DISTURBANCE PASSES EAST AND CONVERGENCE ALONG THE DEWPOINT GRADIENT WEAKENS...WOULD EXPECT CONVECTION TO DIMINISH THIS EVENING BEFORE THE NEXT IMPULSE KICKS OUT FROM CO. LOWS TONIGHT SHOULD RANGE FROM THE UPPER 40S NEAR THE NEB STATE LINE WHERE LESS CLOUD COVER AND MUCH DRYER AIR COULD HELP TEMPS DROP. HAVE LOWS IN THE UPPER 50S ACROSS EAST CENTRAL KS EXPECTING OVERCAST SKIES TO PERSIST FOR MUCH OF THE NIGHT AND THE BOUNDARY LAYER TO REMAIN A LITTLE MORE MOIST. HIGHS FRIDAY ARE EXPECTED TO BE SIMILAR TO TODAYS WITH NO REAL CHANGE IN AIRMASS AND AN EASTERLY WIND PERSISTING WITH PARTLY SUNNY SKIES. THEREFORE LOOKING AT HIGHS IN THE MID TO UPPER 70S. WOLTERS EXTENDED (SATURDAY THROUGH THURSDAY)...SHORTWAVE RIDGING IN BETWEEN TWO UPPER TROUGHS WILL RESIDE OVER THE CWA FOR THE WEEKEND...RESULTING IN DRY AND QUIET WEATHER FOR THE AREA. THE APPROACHING WEAK ASCENT FROM A MODERATE UPPER JET AND AN ASSOCIATED COLD FRONT WILL ARRIVE OVER THE REGION ON SUNDAY NIGHT INTO MONDAY MORNING. A BRIEF PERIOD OF INCREASED CLOUD COVER MAY BE NOTED WITH THIS FEATURE...BUT DRY AIR IN THE H5-7 LAYER SHOULD PROHIBIT ANY MEANINGFUL PRECIPITATION CHANCES. THEREAFTER...DRY WEATHER IS EXPECTED THROUGH THE WORK WEEK WITH A DRY ATMOSPHERE IN PLACE...AND THE CWA REMAINING ON THE SOUTHERN PERIPHERY OF ZONAL FLOW WITH THE PRIMARY WEATHER SYSTEMS RESIDING TO THE NORTH. ANOTHER COLD FRONT IS PROJECTED TO SLIDE INTO THE AREA ON THURSDAY...BUT LOOKS LIKE A DRY PASSAGE ATTM. AS FOR TEMPERATURES...A GRADUAL WARMING TREND FOR AFTERNOON HIGHS IS ON TAP THIS WEEKEND THROUGH WEDNESDAY WITH READINGS IN THE UPPER 70S TO THE MIDDLE 80S. SLIGHTLY COOLER WEATHER WILL RETURN BEHIND THE FRONTAL BOUNDARY ON THURSDAY. BLAIR && .AVIATION... MODELS CONTINUE TO SHOW THE DEEPER MOISTURE REMAINING JUST SOUTH OF THE TERMINALS...SO EXPECT PRECIP CHANCES TO BE CONFINED TO AREAS SOUTH OF FOE AND MHK. SOME MVFR CIGS HAVE TRIED TO DRIFT NORTH INTO THE TERMINALS OVER THE LAST HOUR OR SO. THE LATEST RAP AND NAM RH PROGS SUGGEST THE LOW LEVEL RH WILL GRADUALLY PUSH SOUTH...SO THINK VFR CONDITIONS WILL PREVAIL. WOLTERS && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
306 PM CDT THU SEP 27 2012 ...UPDATED FOR THE SHORT TERM AND SYNOPSIS... .SYNOPSIS... ISSUED AT 237 PM CDT THU SEP 27 2012 AT THE JET STREAM LEVEL OF 250MB, THERE WAS A 70 TO 80 KNOT JET OVER EASTERN ARIZONA EXTENDING TO NORTHEASTERN NEW MEXICO, WITH A NORTHEAST DIRECTION TOWARD SOUTHWEST KANSAS. ANOTHER 70 KNOT JET WAS FROM NORTH OF KANSAS CITY EAST-SOUTHEASTWARD TO SOUTHERN ILLINOIS. THERE WAS ALSO A WEAK EASTERLY JET IN THE 70 KNOT RANGE OVER ONTARIO, WITH YET ANOTHER 90 TO 100KT JET ENTERING EXTREME NORTHWESTERN NORTH AMERICA OVER THE NORTHWESTERN BRITISH COLUMBIA PROVIDENCE. THE 500MB CHART SHOWED A TROUGH FROM EASTERN MONTANA SOUTH INTO SOUTHWESTERN NEW MEXICO. A LOW PRESSURE AREA WAS OVER NORTHERN COLORADO, WITH A TROUGH EXTENDING EASTWARD OVER NORTHERN COLORADO INTO NORTH CENTRAL KANSAS. A LARGE MOISTURE FIELD RAN FROM WESTERN TEXAS NORTH THROUGH THE TEXAS AND OKLAHOMA BORDER, THEN TURNED EAST INTO SOUTHWESTERN MISSOURI. THE 700MB ANALYSIS SHOWED ONE TROUGH FROM SOUTHEASTERN KANSAS THROUGH CENTRAL OKLAHOMA INTO THE NORTHWESTERN TEXAS PANHANDLE. ANOTHER TROUGH WAS FROM NORTHWESTERN NORTH DAKOTA SOUTH TO A LOW PRESSURE AREA OVER NORTHERN COLORADO, TO NORTHWESTERN NEW MEXICO. THERE WAS A COOL POCKET OF +04C AIR OVER SOUTHERN WISCONSIN. A LARGE MOISTURE FIELD WITH DEW POINT DEPRESSIONS LESS THAN 5C WAS FROM EXTREME SOUTHWESTERN IDAHO SOUTHEAST TOWARD NORTHWESTERN ARKANSAS. THE 700MB TEMP/WINDS AT DDC WERE +03C/30010KTS. DOWN AT THE 850MB CHART, A LOW PRESSURE AREA OVER NORTHEASTERN COLORADO HAD A FRONT EXTENDING TO THE SOUTHEAST DIRECTION TO THE EASTERN TEXAS PANHANDLE, SWOOPING SOUTHEAST THROUGH SOUTHERN OKLAHOMA, AND THEN BACK TO THE NORTHEAST INTO SOUTHERN ILLINOIS. A SLIGHT WARM POCKET OF AIR WAS LODGED OVER THE NORTHERN PLAINS IN NORTHWESTERN SOUTH DAKOTA WITH +18C TEMPS. ANOTHER COOL TONGUE OF AIR WAS FROM ONTARIO SOUTHWESTWARD TO EASTERN IOWA, WITH TEMPERATURES AS LOW AS -03C OVER THE NORTHEASTERN GREAT LAKES. THE 850MB TEMP/WINDS AT DDC WERE +14C/24007KT RESPECTFULLY. && .SHORT TERM...(THIS EVENING THROUGH TOMORROW) ISSUED AT 237 PM CDT THU SEP 27 2012 THE FIRST PRIORITY FOR THIS FORECAST IS THE CHANCE FOR SEVERE STORMS VERY LATE THIS AFTERNOON AND THIS EVENING. TEMPERATURES AND WINDS ARE OF A SECONDARY CONCERN. THE SPC DAY ONE OUTLOOK HAS OUR SOUTHWEST CORNER, SOUTHWEST OF A HAMILTON TO GRANT TO SEWARD LINE, IN A SLIGHT CHANCE. I THINK THERE COULD BE ONE OR TWO OR THREE HAIL PRODUCERS IN OUR WEST/SOUTHWEST CORNER, BUT MAINLY AFTER 9 PM CDT. THE HRRR MODEL HAS JUST MARGINAL CAPE THIS EVENING IN THE 1000 J/KG, THE RUC MODEL HAS LITTLE OR NO 0-6 KM HELICITY, AND FORECAST SOUNDINGS FROM BOTH THE HRRR AND RUC MODELS FOR A POINT NEAR RICHFIELD SHOW -5.8 LI`S BY 06Z. IF THERE IS SOME SEVERE, IT WILL BE A LATE SHOW AFTER 9PM CDT. WE HELD A EMS/KDOT/FEMA CONTACTS, AND TOLD THEM POSSIBLE HAILERS WITH UP TO GOLF BALL HAIL AFTER 7 PM CDT, SO THEY SHOULD HAVE PLENTY OF NOTICE. AFTER THE FIRST ROUND OF MARGINAL SEVERE CONVECTION, THERE IS A GOOD WAVE MOVING EAST ACROSS OUR CWA AFTER MIDNIGHT. THEREFORE, THERE WILL BE INCREASING POPS AFTER 06Z, FROM WEST TO EAST. THERE COULD BE A GOOD WIDESPREAD RAIN EVENT, BUT DID NOT OVERDO THE RAINFALL QPF SINCE HIGH RAINFALL AMOUNTS WILL SPOTTY SUCH AS THE LAST SEVERAL PRECIPITATION EVENTS. LAST NIGHT, DOWN NEAR LIBERAL, WE HAD ONE RAINFALL REPORT OF 3.50 INCHES 2 MILES SOUTH OF LIBERAL AND ANOTHER REPORT OF 2.61 INCHES OF RAIN FROM THE SOUTH-SOUTHWEST EDGE OF ROLLA. SO, WIDESPREAD RAIN LIKE THAT IS NOT EXPECTED AGAIN. THE RUC13 MODEL SOUNDING FOR NEAR ELKHART SHOWED 1.13 INCHES AT 06Z. OUR EASTERN CWA SHOULD STAY CLOUDY TONIGHT WITH 3-5SM FOG, AND THE WEST WILL LIKELY SEE EVEN LOWER LEVEL CLOUDS IN THE EASTERLY UPSLOPE FLOW. TEMPERATURES WILL NOT FALL QUICKLY UNDER THE THICK CLOUDS, AND SHOULD ONLY BOTTOM OUT IN THE MID 50S IN THE WEST AND THE LOWER 60S IN THE SOUTHEAST. FRIDAY COULD STILL BE WET WITH SCATTERED SHOWERS AND THUNDERSTORMS, WITH THE BETTER CHANCE IN OUR EASTERN COUNTIES EAST OF A LINE FROM HAYS TO DODGE CITY TO ASHLAND. THIS MAY BE AN EARLY MORNING THEN ANOTHER ROUND OF RAIN IN THE AFTERNOON EVENT. POPS WILL BE 40 TO 50 PERCENT EAST OF THAT LINE ABOVE, WITH 30 TO 40 POPS WEST OF THAT LINE. HOW MUCH RAIN IS ALWAYS THE QUESTION CALLERS SEEM TO ASK, BUT DO NOT THINK ANY ADDITIONAL HEAVY RAIN WILL FALL ON FRIDAY. THE UPPER SUPPORT WILL BE PULLING EAST DURING THE AFTERNOON, AND THE SURFACE FRONT SHOULD BE MOVING SOUTH OUT OF OUR CWA DURING THE AFTERNOON. LIGHT BUT STEADY UPSLOPE FLOW WILL BE THE MAIN SOURCE OF PRECIPITATION FRIDAY. FRIDAY AFTERNOON SHOULD BE ANOTHER COOL ONE, AS TEMPERATURES WILL STRUGGLE TO REACH THE MID 70S IN OUR EASTERN ZONES OF ELLIS, EDWARDS AND CLARK COUNTIES (AND EAST) AND IN THE LOWER 70S TO DOWN NEAR 70F DEGREES OUT WEST NEAR THE COLORADO BORDER NEAR THE STRONGEST UPSLOPE AFFECT. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 322 AM CDT THU SEP 27 2012 FRIDAY THROUGH SATURDAY NIGHT: CHALLENGING FORECAST WITH RESPECT TO PRECIPITATION DURING THIS PERIOD...MAINLY BECAUSE IT IS DIFFICULT TO HONE IN ON A STRONG SIGNAL FOR LARGE SCALE ASCENT...AND WHAT SIGNAL THERE IS FOR UPWARD VERTICAL MOTION IS DIFFERENT DEPENDING ON WHICH GLOBAL MODEL ONE IS LOOKING AT. ALL THAT BEING SAID...WEAK LOW LEVEL CONVERGENCE FRIDAY INTO FRIDAY EVENING COMBINED WITH RICH LOW LEVEL MOISTURE (SURFACE DEWPOINTS IN THE LOWER 60S DEGF)...AND BROAD UPPER TROPOSPHERIC JET MAX FROM NEW MEXICO INTO THE SOUTHERN/CENTRAL GREAT PLAINS (WHICH IS ENHANCED DUE TO THE REMNANTS OF TROPICAL CYCLONE MIRIAM). ALSO...MID LEVEL TEMPERATURES WILL CONTINUE TO BE COOL WITH 700MB TEMPS AROUND +4 OR +5C...SO ANY DIURNAL INSOLATION WILL ENHANCE THE PROBABILITY FOR SHOWERS/THUNDERSTORMS JUST ABOUT ANYWHERE AMIDST THE MOIST SFC-700MB AIRMASS. EVENTUALLY...THE UPPER TROPOSPHERIC JET WILL SHIFT EAST INTO THE LOWER MISSISSIPPI VALLEY/SOUTHEASTERN CONUS AND PROBABILITY OF PRECIPITATION WILL DIMINISH...ESPECIALLY BY SATURDAY. HAVE DECIDED TO INCREASE POPS INTO LIKELY RANGE (60 POPS) MAINLY SOUTH CENTRAL KANSAS (SOUTHEAST OF ENGLEWOOD-STAFFORD LINE) CLOSER TO THE LOW LEVEL DEFORMATION/CONVERGENCE ZONE. GIVEN THE SOMEWHAT COOL LOWER TROPOSPHERE AND PROPENSITY FOR CLOUDS AND PRECIPITATION...HIGHS IN THE LOWER TO MID 70S LOOK GOOD FOR FRIDAY. THE SAME CAN BE SAID FOR SATURDAY WITH SIMILAR TEMPERATURES IN THE FORECAST WITH 850/700MB TEMPS AVERAGING +16/+5C ACROSS SOUTHWEST KANSAS. VERY LIGHT WINDS (IF NOT CALM AT TIMES), HIGH DEWPOINTS IN THE UPPER 50S/LOWER 60S, AND WET GROUNDS WILL CONTINUE TO SUPPORT DEVELOPMENT OF AREAS DENSE FOG BOTH FRIDAY NIGHT AND SATURDAY NIGHT. WILL NOT YET INSERT MENTION OF FOG IN THE GRIDS FOR THESE PERIODS AND LET FUTURE SHIFTS ASSESS THIS FORECAST ELEMENT. SUNDAY THROUGH WEDNESDAY: A WEAK NORTHWEST FLOW DISTURBANCE WILL MOVE SOUTH-SOUTHEAST THROUGH THE HIGH PLAINS SUNDAY WHICH WILL PROVIDE ANOTHER SLIGHT CHANCE WIDELY SCATTERED SURFACE-BASED CONVECTION. THE LATEST ALLBLEND GUIDANCE YIELDED 20 POPS FOR MUCH OF WEST CENTRAL/SOUTHWEST KANSAS FOR THE SUNDAY PERIOD AND WILL NOT DEVIATE FROM THIS. AFTER THIS WEAK WAVE MOVES THROUGH...AN EXTENDED PERIOD OF DRY WEATHER IS EXPECTED AS A PRONOUNCED UPPER LEVEL HIGH BECOMES ESTABLISHED ACROSS THE SOUTHWESTERN CONUS. HIGH TEMPERATURES EARLY NEXT WEEK WILL AVERAGE LOWER TO MID 80S FOR MUCH OF THE REGION WITH THE DOMINANT UPPER LEVEL JET WELL TO THE NORTH ALONG THE US-CANADA BORDER EARLY-MID NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1150 AM CDT THU SEP 27 2012 FOR THIS AFTERNOON, EXPECT MVFR CIGS IN THE BKN-OVC025-030 RANGE AND VSBYS IN THE 5-6SM BR/HZ RANGE. THERE IS A SLIGHT CHANCE THROUGH 21Z ANY ONE TAF MAY DIP TO IFR CIGS IN THE BKN008 RANGE, BUT THOSE CIGS SHOULD BE SHORT LIVED. LIGHT WINDS EARLY WILL BECOME ESTABLISHED FROM THE EAST AT 10 TO 12 KNOTS THIS AFTERNOON. THERE IS ALSO A SLIGHT CHANCE FOR STRAY THUNDERSTORMS AFTER 22Z, ALONG WITH MVFR CIGS. LATER TONIGHT, CLOUDS AND FOG WILL ROLL BACK IN AFTER 06Z, GENERALLY IN THE MVFR CATER GORY FOR VSBYS IN 3-4SM BR. LOW STRATUS WILL BRING CIGS IN THE IFR CATEGORY, APPARENTLY IN THE OVC007 RANGE. && .PRELIMINARY POINT TEMPS/POPS... DDC 60 73 57 76 / 60 50 30 20 GCK 58 72 56 75 / 60 40 30 20 EHA 57 74 56 76 / 70 40 30 20 LBL 58 73 57 77 / 70 50 30 20 HYS 58 74 56 75 / 40 50 30 10 P28 62 75 60 76 / 60 60 40 20 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BURKE SHORT TERM...BURKE LONG TERM...UMSCHEID AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1215 PM CDT THU SEP 27 2012 .DISCUSSION... SEE PREV DISCUSSION. && .AVIATION... MODELS CONTINUE TO SHOW THE DEEPER MOISTURE REMAINING JUST SOUTH OF THE TERMINALS...SO EXPECT PRECIP CHANCES TO BE CONFINED TO AREAS SOUTH OF FOE AND MHK. SOME MVFR CIGS HAVE TRIED TO DRIFT NORTH INTO THE TERMINALS OVER THE LAST HOUR OR SO. THE LATEST RAP AND NAM RH PROGS SUGGEST THE LOW LEVEL RH WILL GRADUALLY PUSH SOUTH...SO THINK VFR CONDITIONS WILL PREVAIL. WOLTERS && .PREV DISCUSSION... /345 AM CDT THU SEP 27 2012/ SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO MOVE NORTHEAST ACROSS SOUTHEAST KANSAS INTO MISSOURI IN AN AREA OF ISENTROPIC LIFT OVER THE FRONTAL BOUNDARY IN OKLAHOMA DUE TO THE LOW LEVEL JET. FURTHER NORTH SKIES HAVE BRIEFLY CLEARED NORTH OF INTERSTATE 70 AND ALLOWED FOG TO QUICKLY FORM HOWEVER HIGH CLOUDS CONTINUE TO SPREAD NORTHWARD AND SHOULD THICKEN OVER TIME. THIS SHOULD KEEP THE FOG FROM BECOMING WIDESPREAD AND WILL ADD A COUPLE OF HOURS OF PATCHY FOG TO THE FORECAST. MODELS ARE IN GENERAL AGREEMENT FOR TODAY WITH KEEPING THE BOUNDARY SOUTH IN OKLAHOMA AND MOST OF THE PRECIPITATION SOUTH OF THE CWA FOR THE BULK OF THE DAY. THE UPPER LOW/TROUGH OVER THE ROCKIES WILL BEGIN TO MOVE EASTWARD THIS EVENING INTO THE HIGH PLAINS WHILE SOME PIECES OF ENERGY MOVE EASTWARD ACROSS THE STATE. WITH THE FRONTAL BOUNDARY AND DEEPER MOISTURE SOUTH BEST CHANCES OF RAINFALL WILL BE MAINLY SOUTH OF INTERSTATE 70 WITH THE HIGHEST CHANCES NEAR THE OKLAHOMA BORDER. THE UPPER TROUGH WILL MOVE SLOWLY EASTWARD BEFORE WEAKENING IN THE AFTERNOON. DRIER AIR AT THE SURFACE WILL MOVE IN FROM THE NORTHEAST DUE TO SURFACE HIGH FROM THE GREAT LAKES SOUTHWEST INTO NORTHEAST KANSAS. LOBES OF ENERGY WILL MOVE ACROSS THE AREA DURING THE DAY. THIS WILL BRING A CHANCE OF THUNDERSTORMS TO AREAS MAINLY SOUTH OF INTERSTATE 70 AND ACROSS PARTS OF NORTH CENTRAL KANSAS. FRIDAY NIGHT LOOKING DRY WITH THE FRONT AND UPPER SUPPORT OVER OKLAHOMA AND EASTERLY WINDS ADVECTING DRIER AIR INTO NORTHEAST KANSAS. FOR THE WEEKEND WEAK UPPER FLOW FROM THE NORTHWEST WILL SEE SOME RIDGING BETWEEN TWO UPPER TROUGHS ONE MOVING ACROSS THE DAKOTAS AND THE OTHER IN THE NORTHEAST. SHOULD END OF BEING FAIRLY NICE WITH HIGHS IN THE UPPER 70S SATURDAY AND SUNDAY. MONDAY THROUGH WEDNESDAY THE THE UPPER FLOW WILL TRANSITION FROM NORTHWEST ON MONDAY TO A ZONAL FLOW BY WEDNESDAY. THE MAIN BELT OF THE WESTERLIES WILL BE NORTH OVER THE DAKOTAS. EXPECTING DRY WEATHER THROUGH THIS TIME PERIOD WITH TEMPERATURES ABOVE NORMAL IN THE LOW TO MID 80S. 53 && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1140 PM MDT WED SEP 26 2012 .UPDATE... ISSUED AT 1121 PM MDT WED SEP 26 2012 LINE OF THUNDERSTORMS ASSOCIATED WITH THE MAIN UPPER LOW IS MOVING ACROSS NORTHEAST COLORADO AND WILL OVERSPREAD THE WESTERN THIRD OF THE FORECAST AREA OVERNIGHT...AND ALL BUT THE FAR EASTERN COUNTIES THURSDAY MORNING. THE THREAT FOR SEVERE WEATHER APPEARS TO HAVE DIMINISHED AS LATEST MESOANALYSIS FROM SPC SHOWS MUCAPE LESS THAN 500 J/KG AND MINIMAL DOWNDRAFT CAPE. OTHER QUESTION FOR THE OVERNIGHT PERIOD WILL BE FOG. RUSSELL AND SALINA HAVE FOGGED IN AT A QUARTER MILE IN THE LAST COUPLE OF HOURS. RUC SHOWS FOG/STRATUS DEVELOPING IN THE EASTERN FORECAST AREA OVERNIGHT. DEW POINT DEPRESSIONS ARE GRADUALLY LOWERING IN THE EAST...ALTHOUGH CLOUDINESS AHEAD OF THE UPPER SYSTEM WILL INHIBIT RADIATIONAL COOLING. DECIDED TO GO WITH PATCHY FOG FOR NOW UNTIL SEE SOME SIGNS OF FOG DEVELOPING IN THE OBS. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 200 PM MDT WED SEP 26 2012 THE UPPER LEVEL TROUGH NORTH OF THE FOUR CORNERS AREA WILL REMAIN NEARLY STATIONARY THROUGH THE NIGHT. MEANWHILE THE AXIS OF CONVERGENCE WILL SLOWLY PROGRESS NORTHEAST OUT OF THE AREA. AS THE SUN SETS...AM ANTICIPATING ANY LINGERING STORMS ALONG THIS BAND TO DISSIPATE. DURING THE OVERNIGHT HOURS AN UPPER LEVEL SHORT WAVE TROUGH WITHIN THE SOUTHWEST FLOW MOVES OVER THE SOUTHWEST PART OVER THE AREA. THE 700-500MB LAPSE RATES AHEAD OF THE TROUGH STEEPEN WITH 150-300J/KG OF MU CAPE DEVELOPING IN THE LAYER. 0-6KM SHEAR INCREASES FROM 20 TO 30KTS NEAR SUNRISE...HOWEVER AM NOT ANTICIPATING ANY SEVERE THUNDERSTORMS ALTHOUGH A FEW MAY BECOME STRONG WEST OF THE COLORADO BORDER PRODUCING SMALL HAIL OR GUSTY WINDS. IN ADDITION ISENTROPIC LIFT DEVELOPS OVER THE WEST OF THE COLORADO BORDER AHEAD OF THE TROUGH FURTHER AIDING IN LIFT. HAVE PRECIP. CHANCES MOVING INTO THE AREA FOLLOWING THE TROUGH...WITH CHANCES INCREASING AFTER MIDNIGHT TOWARD THE SOUTHWEST. OVERNIGHT FOG MAY DEVELOP OVER THE MAJORITY OF THE AREA DUE TO DEW POINTS REMAINING IN THE 50S. CURRENTLY AM ANTICIPATING VISIBILITIES TO DROP TO A MILE IN THE DENSEST FOG. THE FOG SHOULD BURN OFF A COUPLE HOURS AFTER SUNRISE. THURSDAY THE UPPER LEVEL TROUGH NORTH OF THE FOUR CORNERS AREA BEGINS TO PROGRESS EASTWARD. AS IT APPROACHES THE TRI-STATE AREA SMALLER DISTURBANCES DEVELOP AHEAD OF THE MAIN TROUGH OVER THE WESTERN PART OF THE AREA...WITH THE BEST CHANCES OCCURRING MID DAY. POINT SOUNDINGS FROM ACROSS THE AREA INDICATE 500J/KG OF SURFACE BASED CAPE TO WORK WITH...SO THUNDERSTORMS ARE NOT OUT OF THE QUESTION. PRECIP. CHANCES WILL DECREASE DURING THE LATE AFTERNOON AS LIFT FROM THE UPPER LEVEL TROUGH MOVES OUT OF THE AREA. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 200 PM MDT WED SEP 26 2012 THURSDAY NIGHT-SUNDAY...STILL SOME DIFFERENCES IN THE HANDLING OF THE WAVE THAT MOVES INTO THE AREA THURSDAY. THIS WAVE SHOULD MOVE EAST THURSDAY NIGHT GIVEN THE NORTHWEST UPPER FLOW WITH THE GFS/ECMWF THE FASTEST...THE NAM/GEM THE SLOWEST. EITHER WAY...FRIDAY THROUGH MOST OF SATURDAY WILL BE DRY. MAY SEE SOME THUNDERSTORMS VERY LATE IN THE DAY SATURDAY NEAR THE FLAGLER AREA AS A DISTURBANCE MOVES IN FROM THE NORTHWEST. THIS DISTURBANCE LOOKS TO CONTINUE MOVING GENERALLY ACROSS THE REMAINDER OF THE AREA SATURDAY NIGHT AND SUNDAY WHERE SOME SLIGHT CHANCE POPS LOOK WARRANTED. HIGH TEMPERATURES FRIDAY 65 TO 70 IN EASTERN COLORADO WHERE CLOUDS AND PRECIPITATION MOST LIKELY...70-75 FURTHER EAST. WITH LESS CLOUDINESS EXPECTED SATURDAY AND 850 TEMPERATURES WARMING ABOUT 3-5F HIGHS IN THE MID TO UPPER 70S EXPECTED. ON SUNDAY A BIT WARMER WITH MID 70S TO AROUND 80. OVERNIGHT LOWS A BIT ABOVE NORMAL. SUNDAY NIGHT-WEDNESDAY...PRETTY GOOD AGREEMENT THAT A LARGE RIDGE OF HIGH PRESSURE SLOWLY MOVES TOWARD THE AREA THROUGH THE PERIOD. PRECIPITATION IS NOT EXPECTED AND FOR THAT MATTER MUCH IN THE WAY OF CLOUDINESS. A SLOW WARMING TREND WILL CONTINUE WITH MID 70S TO LOW 80S MONDAY...LOW TO MID 80S BY WEDNESDAY. OVERNIGHT LOWS ABOVE NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1121 PM MDT WED SEP 26 2012 AT KGLD...SHOWERS AND THUNDERSTORMS IN EASTERN COLORADO WILL MOVE INTO NORTHWEST KANSAS OVERNIGHT AND CONTINUE THROUGH MUCH OF THURSDAY. CEILINGS WILL BE LOWERING WITH THE ARRIVAL OF THE PRECIPITATION BETWEEN 09-12Z AND SHOULD STAY IFR THROUGH MUCH OF THURSDAY. OCCASIONAL LIGHTNING STRIKES/CB WILL BE POSSIBLE...BUT STORMS ARE NOT EXPECTED TO BE SEVERE. BRIEF RESTRICTIONS IN VISIBILITY WILL ALSO OCCUR NEAR ANY THUNDERSTORM. AT KMCK..BIG QUESTION AS TO WHETHER FOG/STRATUS WILL DEVELOP OVERNIGHT AND INTO THURSDAY MORNING. CURRENT OBSERVATIONS SUGGEST THERE MAY BE SEVERAL HOURS OF REDUCED VISIBILITY AND LOWER CEILINGS...BUT UNSURE HOW LOW TO GO SINCE NEAREST FOG IS CURRENTLY IN RUSSELL KANSAS. MID/HIGH CLOUDS ARE PREVENTING FURTHER RADIATIONAL COOLING...SO FOG WILL HAVE TO ADVECT FROM THE SOUTH WHICH IS SHOWN BY SOME OF THE HIGHER RESOLUTION MODELS. FOR NOW...WILL HAVE A TEMPO GROUP FOR FOG/STRATUS AROUND SUNRISE WHICH IS THE CLIMATOLOGICALLY FAVORED TIME. PRECIPITATION WILL LIKELY HOLD OFF IN KMCK UNTIL LATE THURSDAY AFTERNOON OR THURSDAY NIGHT. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...024 SHORT TERM...JTL LONG TERM...99 AVIATION...024
AREA FORECAST DISCUSSION
NWS WICHITA KS
1155 PM CDT WED SEP 26 2012 .UPDATE... REST OF THE NIGHT: AREAS OF FOG...DENSE IN A SOME AREAS...DEVELOPED QUICKLY OVER CNTRL KS LATE THIS EVENING WHERE SKIES HAD CLEARED. VBSYS DROPPED DRAMATICALLY ~1115PM. HAVE CHECKED SWING ON DENSE FOG ADVISORY ISSUANCE...FOR NOW. AREAL EXTENT BEING WATCHED CLOSELY. TSRA THAT HAVE BEEN OCCURRING OVER MOST OF OK THROUGHOUT THE EVENING APPEAR TO HAVE FORCED SFC FRONT S TOWARD SRN OK...HOWEVER OUTFLOW MAKING LOCATION CHALLENGING. POSSESS SUFFICIENT CONFIDENCE TO LOWER POPS CONSIDERABLY FOR ALL AREAS WITH POPS REMOVED FROM CNTRL KS. POPS FOR REST OF CWA NOW RANGE FROM 40-50% FOR OK-BORDERING COUNTIES TO ~20% ALONG HIGHWAY 400. && .AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU THERE ARE NOW MAJOR CONCERNS FOR KSLN & KRSL WHERE +FG DEVELOPED AND THICKENED RAPIDLY ~0415Z. THEREFORE PLACED BOTH TERMINALS IN VLIFR STATUS FOR REST OF THE NIGHT. IT APPEARS...FOR NOW...THAT BOTH TAF SITES WILL RAPIDLY RETURN TO VFR STATUS 14-15Z. HOWEVER! EXTENSIVE MID-LVL CONVECTIVE DEBRIS IS SPREADING N & NE TOWARD CNTRL KS...SO THIS WOULD DRAW CONSIDERABLE ATTENTION AS MORNING APPROACHES. TSRA STILL ANTICIPATED FOR MUCH OF THE NEIGHBORHOOD ON THU BUT SCT NATURE OF CONVECTION DICTATES ASSIGNING "VCTS" TO MOST TERMINALS FROM 15Z ONWARD. && .PREV DISCUSSION... /ISSUED 700 PM CDT WED SEP 26 2012/ AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU EARLY THIS EVENING A STATIONARY FRONT EXTENDED FROM THE TX PANHANDLE JUST N OF KAMA DUE E ACROSS CNTRL OK TO NRN AR. ANTICIPATE THE FRONT TO REMAIN SITUATED OVER THESE AREAS FOR MOST OF THE NIGHT & AS SUCH BULK OF TONIGHT`S CONVECTION SHOULD LIKEWISE REMAIN OVER OK. IT IS CONCEIVABLE THAT AS THE LOW-LVL JET DEVELOPS THE 925-MB FRONT MAY GET FORCED ALMOST DUE N TOWARD THE OK/KS BORDER LATE TONIGHT. WITH SOME INDICATION THAT THE FRONT MAY LIFT FURTHER N OVER SE KS HAVE LIMITED "VCTS" MENTION TO KCNU EFFECTIVE 06Z WITH CONVECTION ELEVATED IN NATURE. TSRA POTENTIAL CONTINUES FOR REMAINDER OF TAF PERIOD WITH GREATEST EXISTING ACROSS SC & SE KS ON THU WHERE NO DOUBT CLOSER TO THE AFORE-MENTIONED FRONT. PREV DISCUSSION... /ISSUED 229 PM CDT WED SEP 26 2012/ DISCUSSION... SYNOPSIS...THE MCV LEFT FROM LAST NIGHTS CONVECTION WAS CENTERED ABOUT 55 MILES NORTHWEST OF SALINA. CONVECTION FROM THIS IS FESTERING NEAR AND EAST OF THE CENTER...EXTENDING INTO MISSOURI. A STRONG RESIDENT COLD POOL REMAINED IN PLACE ACROSS THE FORECAST AREA FOR MUCH OF THE MORNING...MAKING RECOVERY OF THE ATMOSPHERE QUITE SLOW. OF NOTE AS WELL IN THE VISIBLE IMAGERY ARE GRAVITY WAVES PROPAGATING AWAY FROM THE CONVECTION TO THE SOUTH AND SOUTHWEST...THE MOST RECENT OF WHICH HAS INCREASING CONVERGENCE ALONG IT. THE COLD POOL HAS PUSHED THE COLD FRONT ALL THE WAY INTO OKLAHOMA AND ARKANSAS...WITH AN 18Z POSITION EXTENDING FROM A KRUE-KFSM-KOKC-KDDC APPROXIMATION. FROM 18Z TO 19Z...TEMPERATURES HAVE RISEN INTO THE MID 70S ACROSS SOUTH-CENTRAL KANSAS WHERE THE COLD POOL HAS NEARLY MIXED OUT. SOME CUMULUS HAVE STARTED TO FORM IN THIS AREA AS A RESULT. UPPER LEVEL ANALYSIS ENDING AT 19Z SHOWS AN UPPER LOW CENTERED OVER THE FOUR CORNERS REGION...WITH IMPULSES OF ENERGY ROTATING AROUND IT. THESE ARE THE MAIN IMPULSES AFFECTING THE AREA. ANOTHER DISTURBANCE WAS NOTED IN THE WATER VAPOR IMAGERY MOVING ALONG THE U.S. CANADIAN BORDER OF CENTRAL MONTANA. A VERY DEEP AREA OF LOW PRESSURE WAS OVER THE GULF OF ALASKA WITH WEAKENING LOW PRESSURE OVER NORTHERN QUEBEC. THE MAIN FORECAST FOCUS WILL BE ON CONVECTION OVER THE NEXT SEVERAL DAYS. TONIGHT - THE MAIN FORCING MECHANISM FOR CONVECTION SHOULD ONCE AGAIN BE LOW LEVEL MOISTURE TRANSPORT INTERSECTING THE FRONT. THE MOISTURE TRANSPORT VECTORS...ISENTROPIC LIFT AT 305K AND 310K...AND THE 1000MB-850MB FRONTOGENESIS REALLY ISOLATE WHERE THIS SHOULD OCCUR. THE BULK OF THE NWP CONTINUE TO FAVOR AN AREA OVER SOUTHEAST KANSAS. THIS IS EXPECTED TO OCCUR LATE THIS EVENING. A SECOND AREA SHOULD CONTINUE IN THE VICINITY OF THE MCV...WHERE CONVECTION FESTERS THIS AFTERNOON. A THIRD AND FINAL AREA OF CONVECTION WILL MOVE INTO THE AREA FROM THE WEST. THE NAM-WRF AND THE HRRR BOTH SHOW STORMS MOVING OFF THE HIGH PLAINS INTO THE WESTERN PART OF THE STATE. THESE REACH THE FORECAST AREA AT VARIOUS TIMES. THE HRRR /MULTIPLE RUNS FROM 10Z THROUGH 15Z/ BRING THIS CONVECTION INTO WESTERN KANSAS BY 01Z...THE 26.12Z NAM-WRF BRINGS IT INTO WESTERN KANSAS BETWEEN 06Z AND 09Z. THIS HAS A GREAT AFFECT ON THE FORECAST AND WHETHER WE GET ADDITIONAL CONVECTION ALONG THE SOUTHERN PERIPHERY OF THE FORECAST AREA. HAVE LOW CONFIDENCE IN TIMING OF THIS SYSTEM. THE LATEST RAP AT 18Z SHOWS A STRONG LOW LEVEL JET ACROSS THE HIGH PLAINS...WHICH WOULD FAVOR THE NAM-WRF. STILL...CONFIDENCE IS RATHER LOW. THURSDAY - ANY ONGOING CONVECTION IN THE MORNING SHOULD GRADUALLY DIMINISH DURING THE MORNING. DURING THE AFTERNOON...THERE SHOULD BE ENOUGH RESIDUAL MOISTURE IN THE BOUNDARY LAYER TO ENABLE SOME ADDITIONAL SHOWERS AND THUNDERSTORMS...THOUGH NOTHING LOOKS ORGANIZED AT THIS TIME. FRIDAY THROUGH WEDNESDAY - HIGH PRESSURE MOVES INTO THE REGION...BOTH THE 26.12Z ECMWF AND THE 26.12Z GFS AGREE ON THAT. THEY ALSO HAVE A COLD FRONT...ASSOCIATED WITH A LOW IN THE NORTHERN STREAM UP IN CANADA...MOVING THROUGH THE REGION ON SUNDAY. THIS FRONT SHOULD BE DRY SINCE THE GULF IS CLOSED OFF. ON WEDNESDAY...ANOTHER COLD FRONT MOVES SOUTH THEN STALLS OVER THE REGION. PRECIPITATION CHANCES WITH THIS FRONT SHOULD BE A BIT BETTER. LOOKING OUT AHEAD...A SIGNIFICANT PATTERN CHANGE MAY BE UNDERWAY. A VERY DEEP TROUGH IS FORECAST TO DEVELOP OVER THE WESTERN U.S. THIS PRODUCES A STRONG DEEP SURFACE LOW OVER THE NATIONS MID-SECTION...WITH STRONG HIGH PRESSURE OVER THE NORTHWESTERN U.S. AND CANADA IN THE LEE OF THE ROCKIES. THIS COULD BE THE FIRST SIGNIFICANT SNOW STORM OF THE SEASON FOR THE NORTHERN PLAINS AND SOUTHERN CANADA. COOK && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 62 76 61 74 / 40 50 60 50 HUTCHINSON 60 75 60 74 / 30 40 50 40 NEWTON 60 75 60 73 / 30 40 50 40 ELDORADO 61 76 60 73 / 40 40 50 50 WINFIELD-KWLD 64 78 63 75 / 40 50 60 50 RUSSELL 54 74 56 74 / 20 30 40 30 GREAT BEND 57 74 58 74 / 20 40 50 40 SALINA 56 76 57 76 / 70 20 30 30 MCPHERSON 59 75 58 74 / 30 40 40 40 COFFEYVILLE 65 79 63 75 / 80 50 70 60 CHANUTE 63 76 61 74 / 60 50 50 40 IOLA 62 76 60 74 / 50 40 40 40 PARSONS-KPPF 64 78 62 75 / 70 50 60 50 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS JACKSON KY
136 AM EDT THU SEP 27 2012 .UPDATE... ISSUED AT 130 AM EDT THU SEP 27 2012 THE LATEST TRENDS IN SATELLITE AND RADAR IMAGERY INDICATE A DISTINCT AND STEADY WEAKENING TREND IN A LINE OF SHOWERS AND STORMS THAT STRETCHES ALONG AND JUST SOUTH OF THE OHIO RIVER FROM CENTRAL KENTUCKY AND ACROSS SOUTHERN OHIO. A FEW SHOWERS AND STORMS HAVE MANAGED TO HOLD TOGETHER LONG ENOUGH TO MOVE ACROSS FLEMING AND BATH COUNTIES...BUT THE BULK OF THE EXISTING STORMS ARE PUSHING NORTHEASTWARD INTO INDIANA AND OHIO. MOST OF THE SHOWERS AND STORMS THAT HAD BEEN MOVING ACROSS CENTRAL KENTUCKY THAT PAST SEVERAL HOURS HAVE DISSIPATED EVERYWHERE EXCEPT ALONG THE RIVER. THAT BEING SAID...AND WITH THAT LATEST MODEL DATA ALSO SUPPORTING IT...HAVE REMOVED MENTION OF PRECIPITATION FROM THE FORECAST FOR THE REST OF THE NIGHT EVERYWHERE EXCEPT POINTS ALONG AND NORTH OF THE I64 CORRIDOR. IT LOOKS THERE WILL BE A LULL IN THE ACTIVITY UNTIL JUST AFTER SUNRISE TODAY...AT WHICH TIME A LOW LEVEL DISTURBANCE AND FRONTAL BOUNDARY BEGIN MAKING THEIR WAY SOUTHWARD TOWARD CENTRAL AND EASTERN KENTUCKY. MOST ACTIVITY WILL LIKELY REMAIN CONFINED TO AREAS NORTH OF THE HAL ROGERS PARKWAY UNTIL AROUND 17Z TODAY. THE FORECAST GRIDS HAVE BEEN MODIFIED TO REFLECT THE AFOREMENTIONED TRENDS IN THE MODEL DATA AND REAL TIME OBSERVATIONS. THE UPDATED ZONE FORECAST TEXT PRODUCT WILL BE ISSUED SHORTLY. UPDATE ISSUED AT 1040 PM EDT WED SEP 26 2012 RADAR REMAINS QUITE ACTIVE AS OF 10 PM WITH A STRUNG OUT LINE OF CONVECTION ALONG THE OHIO RIVER SLOWLY DRIFTING EAST-NORTHEAST ON TRACK TO CLIP OUR BLUEGRASS COUNTIES FROM ABOUT 11 PM THROUGH AROUND 3 AM. OF GREATER CONCERN IS THE LINE OF CONVECTION PUSHING INTO CENTRAL KY...MOVING EAST AT AROUND 30-35 MPH. WARMING CLOUD TOPS AND LOWERING ENHANCED ECHO TOPS ALONG WITH DIMINISHING LIGHTNING ACTIVITY ALL SUGGEST AN OVERALL WEAKENING TREND...HOWEVER A WELL DEFINED OUTFLOW EVIDENT ON THE LMK 0.5 DEG SLICE IS CURRENTLY PUSHING SOUTH ACROSS CENTRAL KY...SET TO INTERCEPT THE INBOUND LINE OF TSTMS FROM THE WEST. THIS LINE APPEARS TO HAVE A GOOD COLD POOL TO WORK WITH AND WITH ADDITIONAL LIFT FROM THE INTERACTION WITH THE OUTFLOW...AM EXPECTING AN UPTICK IN ACTIVITY AS THIS LINE APPROACHES THE LAKE CUMBERLAND REGION. NEAR TERM MODELS CONTINUE TO SHOW ACTIVITY WANING OVER ALL BUT NRN CENTRAL KY BEFORE IT REACHES OUR AREA...BUT HAVE BUCKED THE GUIDANCE AND INCREASED POPS TO LIKELY OVER A GOOD PORTION OF OUR SWRN ZONES FOR THE REMAINDER OF THE OVERNIGHT PERIOD WITH THE EXPECTATION THAT THE LINE OVER CENTRAL KY WILL SURVIVE THE TRANSIT INTO THE CWA. GUSTY WINDS CONTINUE TO APPEAR TO BE THE MAIN THREAT...THOUGH EVEN THE STRONGEST STORMS HAVE ONLY BEEN PRODUCING GUSTS AROUND 35 TO 40 MPH...AND DO NOT FORESEE ANYTHING STRONGER DEVELOPING OVERNIGHT. UPDATED GRIDS...ZONES...AND HWO HAVE BEEN SENT. UPDATE ISSUED AT 650 PM EDT WED SEP 26 2012 SCATTERED CONVECTION CONTINUES TO DRIFT ACROSS OUR BLUEGRASS COUNTIES THIS EVENING WITH RAINFALL THUS FAR LESS THAN 1/4 INCH. THE NEAR TERM GUIDANCE GENERALLY APPEARS TO HAVE A GOOD HANDLE ON THE SCATTERED CONVECTION UPSTREAM OVER WRN KY...DEPICTING THIS ACTIVITY TO DISSIPATE OVER THE NEXT FEW HOURS BEFORE REACHING THE CWA...WITH RESIDUAL ACTIVITY OVERNIGHT REMAINING BELOW SEVERE LIMITS AND PREDOMINANTLY AFFECTING AREAS OVER NERN KY. THE CURRENT FORECAST HAS ALL OF THIS WELL IN HAND...AND GENERALLY ONLY NEEDED MINOR MASSAGING TO THE TEMP AND DEW PT CURVES HEADING INTO THE OVERNIGHT PERIOD. METMOS APPEARS TO HAVE A FAIRLY GOOD HANDLE ON THE TEMP/DEW PT REGIME ATTM...AND IS HINTING AT SOME TYPICAL ERN KY PATCHY VALLEY FOG TOWARDS DAWN...SO WILL ADD THIS TO THE MIX FOR AREAS GENERALLY ALONG AND SOUTH OF THE HAL ROGERS/KY 80 CORRIDOR WHERE CLEARER SKIES ARE EXPECTED TO PREVAIL OVERNIGHT. UPDATED GRIDS HAVE BEEN SENT...AND FRESH ZONES WILL BE ISSUED SHORTLY. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 309 PM EDT WED SEP 26 2012 QUASI STATIONARY FRONTAL BOUNDARY REMAINS FROM LAKE ONTARIO TO NORTHERN ILLINOIS...WHILE ANOTHER WEAK BOUNDARY IS ACROSS NORTHERN KY. A SERIES OF CONVECTIVE COMPLEXES HAS BEEN MOVING ENE THROUGH THE OH VALLEY...AND THIS SCENARIO LOOKS TO CONTINUE THROUGH THE FORECAST PERIOD...WITH A GRADUAL SHIFT SOUTH OF THE ACTIVITY AS THE PRIMARY FRONT SAGS SOUTH. MODEL CONSENSUS IS THAT THE FOCUS OF THE REPEATED RAINS WILL BE NORTHWEST OF THE FORECAST AREA...AND THUS HEAVIEST RAIN TOTALS ARE EXPECTED TO REMAIN OUTSIDE OF FORECAST AREA. HPC HAS PLACED THE EXTREME WESTERN EDGE OF THE FORECAST AREA IN A SLIGHT RISK FOR EXCESSIVE RAINS. PRECIPITABLE WATER IS FORECAST TO BE IN EXCESS OF THE 75TH PERCENTILE...BUT NOT TO BECOME TOO EXCESSIVE WITH PW GETTING UP NEAR 1.5 INCHES. NONE THE LESS IF THE THE REPEATED RAINS SET UP FURTHER SOUTH THE SITUATION WILL NEED TO BE MONITORED CLOSELY. HOWEVER FLOOD THREAT FOR OUR AREA LOOKS MINIMAL AT THIS TIME. CONVECTION CURRENTLY OVER SOUTHEASTERN INDIANA SHOULD REMAIN NORTH OF THE FORECAST AREA LATE THIS AFTERNOON AND EVENING...BUT MAY AFFECT THE FAR NORTHERN PART OF THE FORECAST AREA IF DEVELOPMENT OCCURS FURTHER TO THE SOUTH. CONVECTION NOW OVER SOUTHEASTERN MO IS MORE LIKELY TO AFFECT THE FORECAST AREA TONIGHT...AND THIS IS PICKED UP ON BY THE HRRR. LOW LEVEL JET LOOKS TO INCREASE EARLY TONIGHT...SO THIS SHOULD HELP TO INCREASE THE PRECIPITATION CHANCES...MAINLY IN THE NORTH. THE NORTHERN PART OF THE FORECAST AREA ALSO REMAINS IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS PER THE LATEST SPC DAY 1 OUTLOOK. HOWEVER SINCE CONVECTION DID NOT DEVELOP THIS AFTERNOON ALONG THE OLD BOUNDARY CURRENTLY OVER THE AREA IT APPEARS THE THREAT FOR SEVERE WEATHER WILL BE DECREASING. IT APPEARS WE WILL NEED TO WAIT FOR THE COMPLEX CURRENTLY DEVELOPING OVER MO TO MOVE ACROSS THE AREA TONIGHT. HOWEVER BASED ON LATEST HRRR SHORT RANGE GUIDANCE THIS CONVECTION SHOULD WEAKEN AS IT MOVES INTO OUR AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 309 PM EDT WED SEP 26 2012 MODELS ARE IN FAIR AGREEMENT TO START THE EXTENDED FCST. A SLOWLY SAGGING TROF EXTENDS FROM WEST TO EAST ACROSS THE COMMONWEALTH. PCPN IN THE FORM OF WAVES TRACKS ALONG THE FRONTAL ZONE WITH DIFFERENCES IN THE DETAILS. HIGH PRESSURE FORCES THE FRONTAL ZONE SOUTH OF THE STATE WITH THE GFS SLIGHTLY QUICKER IN CLEARING OUT THE PCPN. HAVE CHOSEN TO FOLLOW THIS TREND AS THE HIGH PRESSURE OVER THE NORTHERN PLAINS INITIALIZES BETTER IN THIS RUN. THIS PLACES CHANCE POPS ACROSS THE ENTIRE CWA WITH 30S IN THE NORTH AND 50S SOUTH ON FRI. FRI NIGHT AND SAT SHOWS CLEARING IN THE NORTH WITH CHANCE POPS IN THE SOUTH FOLLOWED ON SAT NIGHT WITH NO POPS FOR THE ENTIRE AREA. THE DRY WEATHER THEN CONTINUES THRU THE REMAINDER OF THE FCST AS HIGH PRESSURE SETTLES OVER THE CNTRL APPALACHIANS AND THE MID ATLANTIC COAST. THIS HIGH EXTENDS WEST INTO THE CNTRL PLAINS AND CUTS OFF ANY RETURN FLOW FROM THE GULF. HENCE THE DEWPOINTS WILL DROP AS THE DRIER AIR SETTLES IN WITH THE PLAINS HIGH WITH VALUES IN THE UPPER 40S AND LOWER 50S. TEMPERATURES WILL START IN THE MID 70S ON FRI BUT DROP TO THE UPPER 60S WITH THE CLOUDS AND RAIN ON SAT. THEN AS THE FRONT EASES SOUTH LOOK FOR HIGH TEMPS TO RECOVER INTO THE LOWER 70S ON SUN AND CONTINUE CLIMBING SLOWLY TO THE MID 70S AGAIN BY WED. LOWS WILL REMAIN FAIRLY STEADY IN THE 50S WITH MONDAY MORNING THE COOLEST AS THE MERCURY SHOULD FALL TO AROUND 50. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 135 AM EDT THU SEP 27 2012 VFR CONDITIONS ARE EXPECTED TO PREVAIL AT THE TAF SITES UNTIL AROUND 10Z. FROM 10-12Z THIS MORNING...SKIES WILL LIKELY BE CLEAR ENOUGH FOR SOME FOG TO FORM AT AND NEAR LOZ AND SME. SHOWERS AND STORMS THAT HAD BEEN QUITE NUMEROUS ACROSS CENTRAL KENTUCKY DURING THE LATE EVENING HOURS...HAVE SINCE DECREASED GREATLY IN SPATIAL COVERAGE AND INTENSITY. IN FACT...MOST REMAINING SHOWERS AND STORMS ARE CONFINED TO AN AREA ALONG THE OHIO RIVER. IT APPEARS THAT THE TAF SITES WILL BE SPARED FROM SHOWER AND STORM ACTIVITY UNTIL 15Z OR SO TODAY. THE BEST CHANCE FOR SHOWERS AND STORMS AT THE TERMINALS WILL BE FROM 17Z ONWARD TODAY...AS THE SFC BOUNDARY IS EXPECTED TO BECOME ACTIVE AGAIN...BRINGING A RENEWED...MORE WIDESPREAD THREAT OF SHOWERS AND STORMS TO THE AREA. SOUTHERLY WINDS WILL REMAIN LIGHT OVERNIGHT BEFORE REENGAGING AFTER 15Z...VEERING TO THE WEST AT AROUND 5 TO 10 KTS THROUGH THE AFTERNOON AND EVENING. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AR SHORT TERM...SBH LONG TERM....DUSTY AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1106 PM EDT FRI SEP 28 2012 .SYNOPSIS... THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ON THE INCREASE THIS WEEKEND AS A COLD FRONT STALLS ACROSS THE EASTERN CAROLINAS. NEXT WEEK WILL REMAIN UNSETTLED AS LOW PRESSURE DEVELOPS ALONG THE GULF COAST AND MOVES ACROSS THE WESTERN CAROLINAS. A COLD FRONT WILL CROSS THE AREA BY LATE WEEK BRINGING DRIER AND COOLER WEATHER. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 1045 PM FRIDAY...CURRENT CONVECTION AHEAD OF THE COLD FRONT CONTINUES TO DIMINISH IN AREAL COVERAGE DURING THIS EVENING...AND SHOULD CONTINUE THIS TREND OVERNIGHT DUE TO INSTABILITY HAVING WEAKENED. THE OUTFLOWS FROM THE EARLIER STORMS UPSTREAM HAVE REACHED THE NORTHERN 1/3RD OF THE FA. LATEST HRRR HAS NOW BACKED OFF WITH PCPN COVERAGE OVERNIGHT. WILL HOWEVER CONTINUE A SLIGHT CHANCE OF PCPN FOR THE NORTHERN 1/4TH TO 1/3RD PORTIONS OF THE ILM CWA...FOR THE REMAINDER OF THE OVERNIGHT. TWEAKED MIN TEMPS UP SOME WHERE THE THICKER AND MORE OPAQUE CLOUDINESS WILL RESIDE. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 3 PM FRIDAY...MID LEVEL TROUGH DEEPENING OVER EASTERN GREAT LAKES IN RESPONSE TO VERY COLD -24C 500HPA SLIDING DOWN WEST SIDE OF THE TROUGH. COLD FRONT WILL BE DRIVEN INTO THE AREA BY BY LATE AFTERNOON. FAIRLY GOOD FORCING WILL SPREAD ACROSS THE AREA FROM THE NORTHWEST DUE TO HEIGHT FALLS AND INCREASING JETTING ALOFT...AND THERE IS EVEN SOME WEAK LOW LEVEL WARM AIR ADVECTION. A LATE DAY VORT MAX MAY ACT TO ENHANCE POPS ALONG THE COAST...BUT OVERALL PRECIP CHANCES AND AMOUNTS WILL BE SOMEWHAT MARGINALIZED BY A LACK OF PRE-FRONTAL MOISTURE ADVECTION DUE TO THE ABSENCE OF A STRONG HIGH IN THE WESTERN ATLANTIC. ANOTHER MUCH WEAKER UPPER DISTURBANCE WILL DROP INTO THE SOUTHERN MISSISSIPPI VALLEY SATURDAY NIGHT INTO SUNDAY. THIS WILL INCITE CYCLOGENESIS OVER THE NORTHWESTERN GULF OF MEXICO. AS THIS SYSTEM MOVES EASTWARD ACROSS THE GULF IT WILL HALT THE PROGRESS OF THE BOUNDARY ALONG THE COAST OF THE CAROLINAS...AS WILL THE LIFTING OUT OF THE MAIN UPPER LOW MOVING EAST OUT OF THE GREAT LAKES INTO THE NORTHEASTERN U.S. THIS WILL KEEP UNSETTLED WEATHER IN THE FORECAST BUT DUE TO AN OVERALL DECREASE IN FORCING MECHANISM STRENGTH BOTH IN THE LOWER AND MID LEVELS SUNDAY APPEARS TO OFFER LESS RAINFALL OPPORTUNITY. WHETHER OR NOT THIS COMES TO PASS HINGES MAINLY ON THE SPEED AT WHICH THE OFFSHORE FRONT RETURNS AS A WARM FRONT...WHICH IS HIGHLY UNCERTAIN AND POORLY AGREED UPON BY VARIOUS GUIDANCE. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 PM FRIDAY...ACTIVE PATTERN THROUGH THE FIRST HALF OF THE WEEK AS SOUTHERN STREAM VORT SPAWNS GULF COAST CYCLOGENESIS ON MONDAY. AS THE HIGHLY AMPLIFIED 500MB TROUGH AXIS MOVES ONLY VERY SLOWLY EAST THROUGH THE TN VLY...THIS LOW WILL TRAVERSE UP THROUGH THE SPINE OF THE APPALACHIAN RANGE AND OFF THE MID-ATLANTIC COAST BY THURSDAY. WARM FRONT STRETCHING FROM THIS LOW WILL PUSH THROUGH THE CWA VERY EARLY MONDAY LEAVING DEEP AND MOIST SOUTHERLY FLOW ACROSS THE REGION. ALTHOUGH CLOUD COVER WILL BE QUITE SIGNIFICANT MON-WED...THE DEEP MOIST FLOW COMBINED WITH MDT STEEP ML LAPSE RATES THANKS TO 500MB TROUGHING...WILL CREATE SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY...FAVORED DURING THE AFTNS. COLD FRONT PUSHES THROUGH ON WEDNESDAY AFTN...LEADING TO A DRIER END OF THE WEEK. CAA HOLDS OFF UNTIL FRIDAY HOWEVER BEHIND A SECONDARY /DRY/ COLD FRONT. TEMPS MONDAY WILL BE RIGHT AROUND CLIMO...BUT WARM TO WELL ABOVE FOR MID-WEEK THANKS TO THE WARM SOUTHERLY FLOW. TEMPS WILL RETURN TO NORMAL OR SLIGHTLY BELOW FOR THE END OF THE WEEK. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...RADAR IMAGERY DEPICTS A WEAK LINE OF SHOWERS WITH ISOLATED THUNDERSTORMS MOVING EASTWARD ACROSS CENTRAL NC. DO NOT ANTICIPATE ANY OF THIS ACTIVITY TO AFFECT ANY TERMINALS...THOUGH CANNOT RULE OUT AN ISOLATED SHOWER ALONG THE OUTFLOW BOUNDARY TO AFFECT THE THE INLAND SITES BEFORE MIDNIGHT. OTHERWISE...EXPECT VFR CONDITIONS OVERNIGHT AT THE COASTAL SITES AS LOW LEVEL WINDS AND CLOUD COVER SHOULD INHIBIT FOG...WHILE MVFR VISIBILITIES CANNOT BE RULED OUT AT THE INLAND TERMINALS. EXPECT INCREASING CLOUD COVER SATURDAY AHEAD OF AN APPROACHING FRONTAL BOUNDARY...WITH TEMPO SUB-VFR CONDITIONS POSSIBLE AS SHOWERS BEGINNING THE MORNING HOURS CONTINUE THROUGHOUT THE PERIOD WITH ISOLATED AFTERNOON THUNDERSTORMS. LIGHT SOUTHWEST WINDS THROUGH THE MORNING HOURS WILL BECOME SOUTH IN THE AFTERNOON...WITH SUSTAINED WINDS AOB 10 KTS. EXTENDED OUTLOOK...POTENTIAL MORNING FOG/STRATUS SUNDAY MORNING MAY REDUCE CIGS/VSBYS TO IFR LEVELS. UNSETTLED WEATHER ASSOCIATED WITH A STALLED FRONTAL BOUNDARY COULD PRODUCE PERIODS OF TEMPO SUB-VFR CONDITIONS ACROSS THE AREA THROUGH WEDNESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1045 PM FRIDAY...A WEAK COLD FRONT WILL BE APPROACHING THE WATERS FROM THE NW LATE TONIGHT AND SAT. DO NOT EXPECT ANY SFC PRESSURE GRADIENT TO DEVELOP AHEAD OF IT...AND AS A RESULT WIND SPEEDS OF 10 KT OR LESS LOOK AOK. IN ADDITION...A WEAK SFC PRESSURE PATTERN AHEAD OF THE FRONT WILL ALSO AFFECT THE ILM WATERS OVERNIGHT INTO SATURDAY. COULD GO VARIABLE IN DIRECTION. AFTER LOOKING AT THE LATEST NAM SFC PRESSURE PATTERN...WILL INDICATE S OR SW INITIALLY...BECOMING WSW OVERNIGHT. A NADINE WAVE TRAIN IDENTIFIED BY THE INCREASED PERIODS OF 10-12 SECONDS WILL BE APPROACHING THE ILM WATERS FROM THE ENE OVERNIGHT...AND LIKELY AFFECTING THE ILM WATERS LATER ON SATURDAY. SIG. SEAS TONIGHT WILL BASICALLY RUN A SOLID 2 FEET AND COMPRISED MAINLY FROM AN EASTERLY SWELL AT 8-9 SECOND PERIODS. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...COLD FRONT MOVES INTO THE AREA LATER SATURDAY. THIS WILL ONLY BRING ABOUT A MARGINAL INCREASE IN THE WINDS AND SEAS FROM THE PREEXISTING VERY TRANQUIL CONDITIONS THAT HAVE BEEN IN PLACE FOR SOME TIME. EXPECTING SW WINDS TO INCREASE TO JUST 10 15KT. BEING LARGELY COAST-PARALLEL THIS WILL BUILD SEAS UP TO 3 FT ALONG THE OUTER REACHES OF THE 20NM FORECAST ZONES. THE FRONT WILL BE DECELERATING ANY MAY VERY WELL STALL SOMEWHERE QUITE CLOSE TO THE COASTAL WATERS FORECAST ZONES...LEADING TO A LITTLE UNCERTAINTY IN THE WIND AND RESULTING SEAS FORECAST. AT THE CURRENT TIME IT APPEARS THAT THE BOUNDARY WILL HEAD BACK TO THE NORTH BY SUNDAY ALLOWING FOR A RETURN OF A SOUTHERLY FLOW...AT LEAST FOR PART IF NOT ALL OF THE AREA. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 300 PM FRIDAY...WARM FRONT WILL BE CROSSING THE WATERS AT THE START OF THE PERIOD...VEERING WINDS TO THE SOUTH WITH INCREASING SPEEDS. WINDS OF 5-10 KTS FROM THE SE WILL QUICKLY BECOME SOUTHERLY AT 10-15 KTS BY LATE MONDAY...AND PERSIST THROUGH EARLY WEDNESDAY. WEAK COLD FRONT APPROACHES EARLY WEDNESDAY AND DISSIPATES OVER THE WATERS...TURNING WINDS BRIEFLY TO THE SW BEFORE BACKING TO THE SOUTH ONCE AGAIN AROUND 10 KTS. WINDS WILL TURN TO THE WEST BY THE END OF THE PERIOD AS A STRONGER SURGE OF DRY AIR PUSHES ACROSS THE WATERS. SEAS INITIALLY 1-2 FT WILL BUILD QUICKLY TO 2-4 FT BY LATE MONDAY AND CONTINUE AT THESE AMPLITUDES THROUGH WEDNESDAY THANKS TO THE STRONG SOUTHERLY WINDS. AS WINDS VEER MORE TO THE WEST LATE WEDNESDAY...SEAS DECREASE TO 2-3 FT AS HIGHEST WAVES GET PUSHED AWAY FROM SHORE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...DCH SHORT TERM...MBB LONG TERM...JDW AVIATION...SGL/BR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
746 PM EDT FRI SEP 28 2012 .SYNOPSIS... THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ON THE INCREASE THIS WEEKEND AS A COLD FRONT STALLS ACROSS THE EASTERN CAROLINAS. NEXT WEEK WILL REMAIN UNSETTLED AS LOW PRESSURE DEVELOPS ALONG THE GULF COAST AND MOVES ACROSS THE WESTERN CAROLINAS. A COLD FRONT WILL CROSS THE AREA BY LATE WEEK BRINGING DRIER AND COOLER WEATHER. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 700 PM FRIDAY...CURRENT CONVECTION AHEAD OF THE COLD FRONT HAS DECREASED IN COVERAGE DURING EARLY THIS EVENING...AND SHOULD CONTINUE THIS TREND AS IT REACHES THE NW PORTIONS OF THE ILM CWA AFTER MIDNIGHT. OUTFLOWS FROM THESE STORMS AHEAD OF THE MAIN CONVECTION HAVE NOT ILLUSTRATED MUCH DEVELOPMENT COMPARED TO 2-3 HRS AGO. THE OUTLINE OF THE CONVECTION CURRENTLY OCCURRING IS SIMILAR TO WHAT THE HRRR IS SHOWING FOR THIS TIME. THE EXCEPTION IS ACROSS WESTERN SC WHERE THE MAIN CONVECTION IS JUST ALONG THE NC-SC BORDER...WITH THE HRRR MODEL EXTENDS IT FURTHER SOUTH TO NEWBERRY SC. USING EXTRAPOLATION AND DIMINISHING DYNAMICS IE. INSTABILITY...WILL HAVE THE ACTIVITY REACH THE NW PORTIONS OF THE ILM CWA NEAR MIDNIGHT. WILL CONTINUE A LOWERED THREAT FOR THE NORTHERN 1/4 PORTIONS OF THE ILM CWA FOR THE REMAINDER OF THE OVERNIGHT. HAVE TWEAKED MIN TEMPS UP BY A DEGREE OR 3 BASED ON WHERE THE THICKER AND MORE OPAQUE CLOUDINESS...AND THE LOW THREAT FOR PCPN. PREVIOUS DISCUSSION............................................... AS OF 300 PM FRIDAY...MOISTURE SPREADING INLAND WITH SEA BREEZE ENHANCING ON SHORE FLOW. THIS GREATER DEWPOINT AIR CREATING GREATER INSTABILITY AS TEMPS SOAR INTO THE MID 80S THIS AFTERNOON. QUITE WIDESPREAD CU DEVELOPMENT ACROSS THE AREA WITH SEA BREEZE PUSHING INLAND CLEARING OUT LOWER CLOUDS ALONG THE COAST. HEATING HAS BEEN HAMPERED SOMEWHAT BY THE CIRRUS STREAMING IN FROM THE WEST. OVERALL EXPECT SKIES TO REMAIN VARIABLY CLOUDY THROUGH THE AFTERNOON WITH TEMPS IN THE MID 80S. COLD FRONT MOVING SOUTHEAST FROM THE OHIO VALLEY INTO THE WESTERN CAROLINAS OVERNIGHT. MID TO UPPER TROUGH BEGINNING TO DIG DOWN FROM THE GREAT LAKES THROUGH TONIGHT. THIS WILL DRIVE COLD FRONT SOUTHEAST FROM THE OHIO VALLEY INTO THE WESTERN CAROLINAS OVERNIGHT. PIECE OF ENERGY ROTATING AROUND MAIN TROUGH WILL REACH DOWN INTO THE NORTH CAROLINA AND SHOULD PROVIDE SUPPORT FOR SHWRS/TSTMS NORTHWEST OF LOCAL AREA INTO THIS EVENING. THIS VORT SWINGS THROUGH RIDING JUST NORTH OF AREA AFTER MIDNIGHT. THE BEST MID TO UPPER LEVEL SUPPORT WILL BE TO OUR NORTHWEST BUT WITH DECENT WESTERLY STEERING FLOW...CAN NOT RULE OUT PCP ALONG NORTHERN TIER COUNTIES AND OVER NORTH CAROLINA COUNTIES OVERNIGHT. THE SOUTHERN HALF OF OUR FORECAST AREA SHOULD REMAIN DRY. CLOUDS AND INCREASED DEWPOINTS IN THE MID 60S WILL KEEP OVERNIGHT LOWS IN THE MID 60S. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 3 PM FRIDAY...MID LEVEL TROUGH DEEPENING OVER EASTERN GREAT LAKES IN RESPONSE TO VERY COLD -24C 500HPA SLIDING DOWN WEST SIDE OF THE TROUGH. COLD FRONT WILL BE DRIVEN INTO THE AREA BY BY LATE AFTERNOON. FAIRLY GOOD FORCING WILL SPREAD ACROSS THE AREA FROM THE NORTHWEST DUE TO HEIGHT FALLS AND INCREASING JETTING ALOFT...AND THERE IS EVEN SOME WEAK LOW LEVEL WARM AIR ADVECTION. A LATE DAY VORT MAX MAY ACT TO ENHANCE POPS ALONG THE COAST...BUT OVERALL PRECIP CHANCES AND AMOUNTS WILL BE SOMEWHAT MARGINALIZED BY A LACK OF PRE-FRONTAL MOISTURE ADVECTION DUE TO THE ABSENCE OF A STRONG HIGH IN THE WESTERN ATLANTIC. ANOTHER MUCH WEAKER UPPER DISTURBANCE WILL DROP INTO THE SOUTHERN MISSISSIPPI VALLEY SATURDAY NIGHT INTO SUNDAY. THIS WILL INCITE CYCLOGENESIS OVER THE NORTHWESTERN GULF OF MEXICO. AS THIS SYSTEM MOVES EASTWARD ACROSS THE GULF IT WILL HALT THE PROGRESS OF THE BOUNDARY ALONG THE COAST OF THE CAROLINAS...AS WILL THE LIFTING OUT OF THE MAIN UPPER LOW MOVING EAST OUT OF THE GREAT LAKES INTO THE NORTHEASTERN U.S. THIS WILL KEEP UNSETTLED WEATHER IN THE FORECAST BUT DUE TO AN OVERALL DECREASE IN FORCING MECHANISM STRENGTH BOTH IN THE LOWER AND MID LEVELS SUNDAY APPEARS TO OFFER LESS RAINFALL OPPORTUNITY. WHETHER OR NOT THIS COMES TO PASS HINGES MAINLY ON THE SPEED AT WHICH THE OFFSHORE FRONT RETURNS AS A WARM FRONT...WHICH IS HIGHLY UNCERTAIN AND POORLY AGREED UPON BY VARIOUS GUIDANCE. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 PM FRIDAY...ACTIVE PATTERN THROUGH THE FIRST HALF OF THE WEEK AS SOUTHERN STREAM VORT SPAWNS GULF COAST CYCLOGENESIS ON MONDAY. AS THE HIGHLY AMPLIFIED 500MB TROUGH AXIS MOVES ONLY VERY SLOWLY EAST THROUGH THE TN VLY...THIS LOW WILL TRAVERSE UP THROUGH THE SPINE OF THE APPALACHIAN RANGE AND OFF THE MID-ATLANTIC COAST BY THURSDAY. WARM FRONT STRETCHING FROM THIS LOW WILL PUSH THROUGH THE CWA VERY EARLY MONDAY LEAVING DEEP AND MOIST SOUTHERLY FLOW ACROSS THE REGION. ALTHOUGH CLOUD COVER WILL BE QUITE SIGNIFICANT MON-WED...THE DEEP MOIST FLOW COMBINED WITH MDT STEEP ML LAPSE RATES THANKS TO 500MB TROUGHING...WILL CREATE SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY...FAVORED DURING THE AFTNS. COLD FRONT PUSHES THROUGH ON WEDNESDAY AFTN...LEADING TO A DRIER END OF THE WEEK. CAA HOLDS OFF UNTIL FRIDAY HOWEVER BEHIND A SECONDARY /DRY/ COLD FRONT. TEMPS MONDAY WILL BE RIGHT AROUND CLIMO...BUT WARM TO WELL ABOVE FOR MID-WEEK THANKS TO THE WARM SOUTHERLY FLOW. TEMPS WILL RETURN TO NORMAL OR SLIGHTLY BELOW FOR THE END OF THE WEEK. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 00Z...RADAR IMAGERY DEPICTS A WEAK LINE OF SHOWERS WITH ISOLATED THUNDERSTORMS MOVING EASTWARD ACROSS CENTRAL NC. DO NOT ANTICIPATE ANY OF THIS ACTIVITY TO AFFECT ANY TERMINALS...THOUGH CANNOT RULE OUT AN ISOLATED SHOWER ALONG THE OUTFLOW BOUNDARY TO AFFECT THE THE INLAND SITES BEFORE MIDNIGHT. OTHERWISE...EXPECT VFR CONDITIONS OVERNIGHT AT THE COASTAL SITES AS LOW LEVEL WINDS AND CLOUD COVER SHOULD INHIBIT FOG...WHILE MVFR VISIBILITIES CANNOT BE RULED OUT AT THE INLAND TERMINALS. EXPECT INCREASING CLOUD COVER SATURDAY AHEAD OF AN APPROACHING FRONTAL BOUNDARY...WITH TEMPO SUB-VFR CONDITIONS POSSIBLE AS SHOWERS BEGINNING THE MORNING HOURS CONTINUE THROUGHOUT THE PERIOD WITH ISOLATED AFTERNOON THUNDERSTORMS. LIGHT SOUTHWEST WINDS THROUGH THE MORNING HOURS WILL BECOME SOUTH IN THE AFTERNOON...WITH SUSTAINED WINDS AOB 10 KTS. EXTENDED OUTLOOK...POTENTIAL MORNING FOG/STRATUS SUNDAY MORNING MAY REDUCE CIGS/VSBYS TO IFR LEVELS. UNSETTLED WEATHER ASSOCIATED WITH A STALLED FRONTAL BOUNDARY COULD PRODUCE PERIODS OF TEMPO SUB-VFR CONDITIONS ACROSS THE AREA THROUGH WEDNESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 700 PM FRIDAY...A WEAK COLD FRONT WILL BE APPROACHING THE WATERS FROM THE NW LATE TONIGHT. DO NOT EXPECT ANY SFC PRESSURE GRADIENT TO DEVELOP AHEAD OF IT...AS A RESULT WIND SPEEDS OF 10 KT OR LESS LOOK AOK. A WEAK SFC PRESSURE PATTERN AHEAD OF THE FRONT WILL ALSO AFFECT THE ILM WATERS OVERNIGHT INTO SATURDAY. COULD GO VARIABLE IN DIRECTION. AFTER LOOKING AT THE LATEST NAM SFC PRESSURE PATTERN...WILL INDICATE S OR SW INITIALLY...BECOMING WSW OVERNIGHT. A NADINE WAVE TRAIN IDENTIFIED BY THE INCREASED PERIODS OF 10-12 SECONDS WILL BE APPROACHING THE ILM WATERS FROM THE ENE OVERNIGHT...AND LIKELY AFFECTING THE ILM WATERS LATER ON SATURDAY. SIG. SEAS TONIGHT WILL BASICALLY RUN A SOLID 2 FEET ...AND COMPRISED MAINLY FROM AN EASTERLY SWELL AT 8-9 SECOND PERIODS. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...COLD FRONT MOVES INTO THE AREA LATER SATURDAY. THIS WILL ONLY BRING ABOUT A MARGINAL INCREASE IN THE WINDS AND SEAS FROM THE PREEXISTING VERY TRANQUIL CONDITIONS THAT HAVE BEEN IN PLACE FOR SOME TIME. EXPECTING SW WINDS TO INCREASE TO JUST 10 15KT. BEING LARGELY COAST-PARALLEL THIS WILL BUILD SEAS UP TO 3 FT ALONG THE OUTER REACHES OF THE 20NM FORECAST ZONES. THE FRONT WILL BE DECELERATING ANY MAY VERY WELL STALL SOMEWHERE QUITE CLOSE TO THE COASTAL WATERS FORECAST ZONES...LEADING TO A LITTLE UNCERTAINTY IN THE WIND AND RESULTING SEAS FORECAST. AT THE CURRENT TIME IT APPEARS THAT THE BOUNDARY WILL HEAD BACK TO THE NORTH BY SUNDAY ALLOWING FOR A RETURN OF A SOUTHERLY FLOW...AT LEAST FOR PART IF NOT ALL OF THE AREA. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 300 PM FRIDAY...WARM FRONT WILL BE CROSSING THE WATERS AT THE START OF THE PERIOD...VEERING WINDS TO THE SOUTH WITH INCREASING SPEEDS. WINDS OF 5-10 KTS FROM THE SE WILL QUICKLY BECOME SOUTHERLY AT 10-15 KTS BY LATE MONDAY...AND PERSIST THROUGH EARLY WEDNESDAY. WEAK COLD FRONT APPROACHES EARLY WEDNESDAY AND DISSIPATES OVER THE WATERS...TURNING WINDS BRIEFLY TO THE SW BEFORE BACKING TO THE SOUTH ONCE AGAIN AROUND 10 KTS. WINDS WILL TURN TO THE WEST BY THE END OF THE PERIOD AS A STRONGER SURGE OF DRY AIR PUSHES ACROSS THE WATERS. SEAS INITIALLY 1-2 FT WILL BUILD QUICKLY TO 2-4 FT BY LATE MONDAY AND CONTINUE AT THESE AMPLITUDES THROUGH WEDNESDAY THANKS TO THE STRONG SOUTHERLY WINDS. AS WINDS VEER MORE TO THE WEST LATE WEDNESDAY...SEAS DECREASE TO 2-3 FT AS HIGHEST WAVES GET PUSHED AWAY FROM SHORE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...DCH/RGZ SHORT TERM...MBB LONG TERM...JDW AVIATION...SGL/BR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
536 PM EDT THU SEP 27 2012 .SYNOPSIS... SLOW MOVING FRONT MOVES EAST OF MOUNTAINS FRIDAY MORNING. UPPER WAVE PASSES ACROSS THE SOUTH WITH AFTERNOON CONVECTION POSSIBLE FRIDAY. DRIER AIR FILTERS IN FROM THE NORTHWEST LATE FRIDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... WILL UPDATE POPS AND SKY COVER FOR LATE THIS AFTERNOON AND EVENING TO BETTER REPRESENT CURRENT RADAR AND SATELLITE TRENDS. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... WILL BE DEALING WITH AMPLIFYING UPR TROF OVER THE AREA THROUGH THE WEEKEND. THIS WILL ALLOW PESKY SFC FRONT TO FINALLY GET THE BOOT S FRI NIGHT. THERE ARE SOME MODEL DISCREPANCIES REGARDING THE SPEED OF THIS...WITH THE NAM SLOWER THAN MOST OF THE OTHER MDLS. IT SEEMS TO BE TOO STRONG WITH WAVE ON THE BOUNDARY AS MOST OF THE MDLS KEEP THINGS MOVING. WILL HEDGE TOWARD FASTER CONSENSUS BUT HOLD SOME SCHC BACK A HAIR TO GIVE NAM A NOD. EXPECT MUCH OF SHRA TO BE CONFINED TO S MTNS AND SW VA THOUGH. MARKED DRYING IN ATMOSPHERIC COLUMN WITH FROPA SHOULD ALLOW MOST PLACES TO CLR IN THE EVE BEFORE SOME HIGHER CLDS TRY TO FILTER IN FROM NW LATE. EXCEPTION BEING SW VA WHERE LINGERING LLVL MOISTURE MAY HOLD IN CLDS INTO SAT MORNING. UPR LOW WILL DROP S INTO LWR LAKES SAT WITHIN AMPLIFYING TROF. MDLS ARE IN DECENT AGREEMENT WITH THIS BUT DIFFER SLIGHTLY WITH EXACT POSITION AND EXTENT OF DEEPER MOISTURE. WILL BE WATCHING VARIOUS SPOKES OF ENERGY DIVING SE FROM UPR LOW LATER ON SAT AND AGAIN ON SUN. APPEARS THE FIRST WILL HAVE LITTLE MOISTURE TO WORK WITH AND BE LEFT MAINLY CLDS ACROSS SE OH AND N WV. DID LEAVE SOME SCHC POPS ACROSS THOSE AREAS WITH MDLS SHOWING SFC LOW DEVELOPMENT OVER UPR OH VALLEY SAT NIGHT. THINK NAM...HOWEVER...IS TOO DEVELOPED WITH THIS FEATURE AS IT ALSO SHOWS QUITE H5 VORT MAX AS WELL. SHOULD SEE MORE OF A DRY SLOT WORK THROUGH EARLY SUN...AHEAD OF ANOTHER PIECE OF ENERGY DIVING SE. THIS ONE LOOKS TO HAVE MORE OF A SFC BOUNDARY TO FOLLOW...WITH NOTICEABLE CAA TO FOLLOW. A THIN BAND OF DEEPER MOISTURE...COMBINED WITH INCREASING LAPSE RATES...MAY ALLOW FOR A SHRA OR TWO IN AFTN ACROSS THE AREA AND HAVE SOME SCHC TO COVER. THINK N AREAS STAND BEST SHOT OF THIS. FOR TEMPS...ROLLED WITH COOLER MAV ACROSS N FRI NIGHT WHERE SOME CLEARING SHOULD ALLOW TEMPS TO DROP NICELY INTO THE 40S. KEPT SW VA AND S WV ON MILD SIDE WITH LINGERING LLVL MOISTURE. GUIDANCE TIGHTLY CLUSTERED FOR HIGHS SAT BUT WOULD NOT BE SURPRISED TO SEE AREA DO A LITTLE BETTER THAN GUIDANCE SUGGESTS IF MORE SUN IS REALIZED. INHERITED NUMBERS LOOKED DECENT REST OF THE WAY AND BLENDED IN WITH A MODEL CONSENSUS. SUN...THOUGH...COULD BE A BIT MILDER THAN FCST SHOULD WAA AHEAD OF FRONTAL BOUNDARY BE GREATER THAN CURRENT THINKING. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... WENT ALONG WITH EC MODELS AS SUGGESTED BY HPC FOR THE EXTENDED PERIOD. CLOSED H500 LOW OVER THE EASTERN GREAT LAKES WILL LIFT OUT SUNDAY NIGHT/MONDAY. EASTERN H500 TROUGH LIFTS OUT THEREAFTER...WITH MAIN BAND OF WESTERLIES PUSHING NORTH. HOWEVER...STOUT UPPER HIGH RETROGRADES ACROSS THE ATLANTIC TOWARDS THE SOUTHEAST U.S. AFTER SUNDAY. THE SOUTHERLY FLOW INDUCED ACROSS THE SOUTHERN U.S. WILL PUSH MOISTURE NORTHWARD. THE FIRST SLUG SHOULD MAINLY STAY OFF TO OUR EAST...KEPT THERE BY AN H500 SHORTWAVE DROPPING IN FROM THE NORTHWEST. A MORE SIGNIFICANT CHANCE OF RAIN MAY ARRIVE AREAWIDE BY WEDNESDAY NIGHT/THURSDAY AS A SHEARING UPPER LOW LIFTS ACROSS THE MISSISSIPPI AND OHIO VALLEYS. LEFT LINGERING LOW CHANCE POPS IN THE NORTHEAST COUNTIES SUNDAY EVENING AS THE UPPER LOW DEPART...THEN A DRY INTERLUDE MONDAY/MONDAY EVENING AS A WEAK SURFACE HIGH MOVES THROUGH. LIMITED POPS TO THE EASTERN SLOPES WITH THE INITIAL SHOT OF MOISTURE MONDAY NIGHT INTO TUESDAY MORNING. THEN...DRY AND WARMER WITH ZONAL FLOW. POPS INCREASE FROM SOUTH TO NORTH WEDNESDAY NIGHT/THURSDAY. HELD OFF ON THUNDER FOR NOW ALTHOUGH THERE MAY BE A TOUCH OF INSTABILITY. MEX AND ENSEMBLE TEMPERATURES WERE GENERALLY IN DECENT AGREEMENT AND DID NOT STRAY FAR. && .AVIATION /22Z THURSDAY THROUGH TUESDAY/... A QUASI STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS WV THIS AFTERNOON AND TONIGHT...BEFORE MOVING EASTER OF THE MOUNTAINS BY 13Z. MOST SYNOPTIC MODELS SEEM TO BE OVERDOING SIGNIFICANT PCPN THIS AFTERNOON SPREADING EAST THROUGH TONIGHT. HIGH RESOLUTION MODELS LOOK MORE RELIABLE WITH ALOT LESS PCPN IN COVERAGE AND INTENSITY. THEREFORE...USED MAINLY WRFARW AND HRRR TO POPULATE POPS NOT MENTIONING THUNDER ANYWHERE AS SOUNDING PROFILE SHOW VERY LITTLE CAPE...LOW LAYERED SHEAR...AND PLENTY OF CLOUDS TO PREVENT ENOUGH HEATING FOR THUNDER. THEREFORE...VFR CONDITIONS EXPECTED THIS AFTERNOON...EXCEPT IFR DURING TEMPOS IN PKB AND CKB UNDER RAIN SHOWERS EARLY THROUGH AROUND 20Z. ALL MODELS SUGGEST ABUNDANT MOISTURE WILL SATURATE LOW LEVELS FOR IFR/LIFR CEILINGS ACROSS MOST SITES AFTER 06Z. VISIBILITIES WILL ALSO DECREASE TO IFR CRITERIA OVER ELEVATED TERRAIN OVERNIGHT. LOW STRATUS SHOULD REMAIN IN PLACE THROUGH AT LEAST 14Z...GRADUALLY LIFTING INTO 16Z LATE FRIDAY MORNING. AREAS WILL BECOME MVFR/VFR FROM WEST TO EAST FRIDAY AFTERNOON AS DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT. AN UPPER LEVEL WAVE COULD TRIGGER SOME CONVECTION ACROSS THE EXTREME SOUTHERN COAL FIELDS FRIDAY AFTERNOON. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SATURDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: TIMING AND INTENSITY OF LOW STRATUS DEVELOPMENT AND DURATION MAY VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY M L M L M M M M M M L L HTS CONSISTENCY M L M M M M M M M M M M BKW CONSISTENCY H M M M M M M M M M M M EKN CONSISTENCY M M M M M M M M M H L M PKB CONSISTENCY M M M M M M M M M M H M CKB CONSISTENCY M M L L M M M M M M L L AFTER 00Z SATURDAY... OCCASIONAL IFR IN CEILINGS AND POSSIBLE SHOWERS OR DRIZZLE OVER SOUTHERN WEST VIRGINIA...THE MOUNTAINOUS COUNTIES OF WEST VIRGINIA...AND SOUTHWEST VIRGINIA FRIDAY AFTERNOON. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...RPY/30/LS/CL NEAR TERM...RPY SHORT TERM...30/LS LONG TERM...CL AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
328 PM EDT THU SEP 27 2012 .SYNOPSIS... SLOW MOVING FRONT MOVES EAST OF MOUNTAINS FRIDAY MORNING. UPPER WAVE PASSES ACROSS THE SOUTH WITH AFTERNOON CONVECTION POSSIBLE FRIDAY. DRIER AIR FILTERS IN FROM THE NORTHWEST LATE FRIDAY. && .NEAR TERM /THROUGH FRIDAY/... A QUASI STATIONARY FRONTAL BOUNDARY MEANDERS ACROSS WV TONIGHT. MODELS SUGGEST IT WILL MOVE EAST OF THE MOUNTAINS BY 12Z FRIDAY. SYNOPTIC MODELS HAVE NOT HANDLE PCPN WELL TODAY. BASED POPS/WX ON THE HIGH RESOLUTION MODELS...ESPECIALLY THE HRRR AND THE WRFARW WHICH BRING SCATTERED SHOWERS ACROSS THE AREA THIS EVENING DIMINISHING OVERNIGHT WITH NO MENTION OF THUNDER. MEANTIME...ABUNDANT LOW LEVEL MOISTURE WITH NOT MUCH UPPER LEVEL SUPPORT SHOULD TRANSLATE INTO WIDESPREAD LOW LEVEL CLOUDS...AND PERHAPS DENSE FOG OVER HIGHER ELEVATIONS OVERNIGHT. THESE CLOUDS WILL STAND STRONG THROUGH AT LEAST 13Z BEFORE START TO DISSIPATE FRIDAY MORNING. THESE FEATURES ARE DEPICTED WITH HIGH CONFIDENCE BY THE SREF PROBABILITIES...AND NAM/RUC/GFS SOUNDING PROFILES. A SLIGHTLY DRIER AIRMASS FILTERS IN FROM THE NORTHWEST AS THE H85 FLOW BECOMES NORTHWEST AS SHOWN BY THE CMC/NAM/GFS/ECWF FRIDAY AFTERNOON...PERHAPS PUSHING EAST THE AFOREMENTIONED CLOUDS...AND SPREADING CLEARING FROM NORTHWEST TO SOUTHEAST FRIDAY EVENING. HOWEVER...A WEAK VORT MAX PASSES SOUTH OF THE AREA FRIDAY. KEPT LIKELY POPS ACROSS THE VIRGINIA COUNTIES FRIDAY AFTERNOON. WITH PLENTY OF CLOUDS OVERNIGHT...AND JUST A DEGREE CELSIUS LOWER THAN PREVIOUS NIGHT AT H850...EXPECT NO RADIATIONAL COOLING AND SLIGHTLY ABOVE NORMAL TEMPERATURES...EXCEPT FOR CRW...GENERALLY IN THE LOW 60S...RANGING TO THE MID 50S HIGHEST ELEVATIONS. THEREFORE...WENT WITH THE WARMER NUMBERS BETWEEN THE MET/MAV GUIDANCE FOR LOWS TONIGHT. HIGH ON FRIDAY WILL DEPEND ON HOW QUICKLY CLEARING SPREAD EAST SOUTHEAST. THEREFORE...KEEP HIGHER TEMPS ACROSS SOUTHEAST OH...GENERALLY IN THE MID 70S...RANGING INTO THE MID 60S HIGHEST ELEVATIONS. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... WILL BE DEALING WITH AMPLIFYING UPR TROF OVER THE AREA THROUGH THE WEEKEND. THIS WILL ALLOW PESKY SFC FRONT TO FINALLY GET THE BOOT S FRI NIGHT. THERE ARE SOME MDL DISCREPANCIES REGARDING THE SPEED OF THIS...WITH THE NAM SLOWER THAN MOST OF THE OTHER MDLS. IT SEEMS TO BE TOO STRONG WITH WAVE ON THE BOUNDARY AS MOST OF THE MDLS KEEP THINGS MOVING. WILL HEDGE TOWARD FASTER CONCENSUS BUT HOLD SOME SCHC BACK A HAIR TO GIVE NAM A NOD. EXPECT MUCH OF SHRA TO BE CONFINED TO S MTNS AND SW VA THOUGH. MARKED DRYING IN ATMOSPHERIC COLUMN WITH FROPA SHOULD ALLOW MOST PLACES TO CLR IN THE EVE BEFORE SOME HIGHER CLDS TRY TO FILTER IN FROM NW LATE. EXCEPTION BEING SW VA WHERE LINGERING LLVL MOISTURE MAY HOLD IN CLDS INTO SAT MORNING. UPR LOW WILL DROP S INTO LWR LAKES SAT WITHIN AMPLIFYING TROF. MDLS ARE IN DECENT AGREEMENT WITH THIS BUT DIFFER SLIGHTLY WITH EXACT POSITION AND EXTENT OF DEEPER MOISTURE. WILL BE WATCHING VARIOUS SPOKES OF ENERGY DIVING SE FROM UPR LOW LATER ON SAT AND AGAIN ON SUN. APPEARS THE FIRST WILL HAVE LITTLE MOISTURE TO WORK WITH AND BE LEFT MAINLY CLDS ACROSS SE OH AND N WV. DID LEAVE SOME SCHC POPS ACROSS THOSE AREAS WITH MDLS SHOWING SFC LOW DEVELOPMENT OVER UPR OH VALLEY SAT NIGHT. THINK NAM...HOWEVER...IS TOO DEVELOPED WITH THIS FEATURE AS IT ALSO SHOWS QUITE H5 VORT MAX AS WELL. SHOULD SEE MORE OF A DRY SLOT WORK THROUGH EARLY SUN...AHEAD OF ANOTHER PIECE OF ENERGY DIVING SE. THIS ONE LOOKS TO HAVE MORE OF A SFC BOUNDARY TO FOLLOW...WITH NOTICEABLE CAA TO FOLLOW. A THIN BAND OF DEEPER MOISTURE...COMBINED WITH INCREASING LAPSE RATES...MAY ALLOW FOR A SHRA OR TWO IN AFTN ACROSS THE AREA AND HAVE SOME SCHC TO COVER. THINK N AREAS STAND BEST SHOT OF THIS. FOR TEMPS...ROLLED WITH COOLER MAV ACROSS N FRI NIGHT WHERE SOME CLRING SHOULD ALLOW TEMPS TO DROP NICELY INTO THE 40S. KEPT SW VA AND S WV ON MILD SIDE WITH LINGERING LLVL MOISTURE. GUIDANCE TIGHTLY CLUSTERED FOR HIGHS SAT BUT WOULD NOT BE SURPRISED TO SEE AREA DO A LITTLE BETTER THAN GUIDANCE SUGGESTS IF MORE SUN IS REALIZED. INHERITED NUMBERS LOOKED DECENT REST OF THE WAY AND BLENDED IN WITH A MDL CONSENSUS. SUN...THOUGH...COULD BE A BIT MILDER THAN FCST SHOULD WAA AHEAD OF FRONTAL BOUNDARY BE GREATER THAN CURRENT THINKING. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... WENT ALONG WITH EC MODELS AS SUGGESTED BY HPC FOR THE EXTENDED PERIOD. CLOSED H500 LOW OVER THE EASTERN GREAT LAKES WILL LIFT OUT SUNDAY NIGHT/MONDAY. EASTERN H500 TROUGH LIFTS OUT THEREAFTER...WITH MAIN BAND OF WESTERLIES PUSHING NORTH. HOWEVER...STOUT UPPER HIGH RETROGRADES ACROSS THE ATLANTIC TOWARDS THE SOUTHEAST U.S. AFTER SUNDAY. THE SOUTHERLY FLOW INDUCED ACROSS THE SOUTHERN U.S. WILL PUSH MOISTURE NORTHWARD. THE FIRST SLUG SHOULD MAINLY STAY OFF TO OUR EAST...KEPT THERE BY AN H500 SHORTWAVE DROPPING IN FROM THE NORTHWEST. A MORE SIGNIFICANT CHANCE OF RAIN MAY ARRIVE AREAWIDE BY WEDNESDAY NIGHT/THURSDAY AS A SHEARING UPPER LOW LIFTS ACROSS THE MISSISSIPPI AND OHIO VALLEYS. LEFT LINGERING LOW CHANCE POPS IN THE NORTHEAST COUNTIES SUNDAY EVENING AS THE UPPER LOW DEPART...THEN A DRY INTERLUDE MONDAY/MONDAY EVENING AS A WEAK SURFACE HIGH MOVES THROUGH. LIMITED POPS TO THE EASTERN SLOPES WITH THE INITIAL SHOT OF MOISTURE MONDAY NIGHT INTO TUESDAY MORNING. THEN...DRY AND WARMER WITH ZONAL FLOW. POPS INCREASE FROM SOUTH TO NORTH WEDNESDAY NIGHT/THURSDAY. HELD OFF ON THUNDER FOR NOW ALTHOUGH THERE MAY BE A TOUCH OF INSTABILITY. MEX AND ENSEMBLE TEMPERATURES WERE GENERALLY IN DECENT AGREEMENT AND DID NOT STRAY FAR. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... A QUASI STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS WV THIS AFTERNOON AND TONIGHT...BEFORE MOVING EASTER OF THE MOUNTAINS BY 13Z. MOST SYNOPTIC MODELS SEEM TO BE OVERDOING SIGNIFICANT PCPN THIS AFTERNOON SPREADING EAST THROUGH TONIGHT. HIGH RESOLUTION MODELS LOOK MORE RELIABLE WITH ALOT LESS PCPN IN COVERAGE AND INTENSITY. THEREFORE...USED MAINLY WRFARW AND HRRR TO POPULATE POPS NOT MENTIONING THUNDER ANYWHERE AS SOUNDING PROFILE SHOW VERY LITTLE CAPE...LOW LAYERED SHEAR...AND PLENTY OF CLOUDS TO PREVENT ENOUGH HEATING FOR THUNDER. THEREFORE...VFR CONDITIONS EXPECTED THIS AFTERNOON...EXCEPT IFR DURING TEMPOS IN PKB AND CKB UNDER RAIN SHOWERS EARLY THROUGH AROUND 20Z. ALL MODELS SUGGEST ABUNDANT MOISTURE WILL SATURATE LOW LEVELS FOR IFR/LIFR CEILINGS ACROSS MOST SITES AFTER 06Z. VISIBILITIES WILL ALSO DECREASE TO IFR CRITERIA OVER ELEVATED TERRAIN OVERNIGHT. LOW STRATUS SHOULD REMAIN IN PLACE THROUGH AT LEAST 14Z...GRADUALLY LIFTING INTO 16Z LATE FRIDAY MORNING. AREAS WILL BECOME MVFR/VFR FROM WEST TO EAST FRIDAY AFTERNOON AS DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT. AN UPPER LEVEL WAVE COULD TRIGGER SOME CONVECTION ACROSS THE EXTREME SOUTHERN COAL FIELDS FRIDAY AFTERNOON. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: TIMING AND INTENSITY OF LOW STRATUS DEVELOPMENT AND DURATION MAY VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY M L M L M M M M M M L L HTS CONSISTENCY M L M M M M M M M M M M BKW CONSISTENCY H M M M M M M M M M M M EKN CONSISTENCY M M M M M M M M M H L M PKB CONSISTENCY M M M M M M M M M M H M CKB CONSISTENCY M M L L M M M M M M L L AFTER 18Z FRIDAY... OCCASIONAL IFR IN CEILINGS AND POSSIBLE SHOWERS OR DRIZZLE OVER SOUTHERN WEST VIRGINIA...THE MOUNTAINOUS COUNTIES OF WEST VIRGINIA...AND SOUTHWEST VIRGINIA FRIDAY AFTERNOON. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/30/LS/CL NEAR TERM...ARJ SHORT TERM...30/LS LONG TERM...CL AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
235 PM EDT THU SEP 27 2012 .SYNOPSIS... SLOW MOVING FRONT MOVE EAST OF MOUNTAINS FRIDAY MORNING. UPPER WAVE PASSES ACROSS THE SOUTH WITH AFTERNOON CONVECTION POSSIBLE FRIDAY. DRIER AIR FILTERS IN FROM THE NORTHWEST LATE FRIDAY. && .NEAR TERM /THROUGH FRIDAY/... A QUASI STATIONARY FRONTAL BOUNDARY MEANDERS ACROSS WV TONIGHT. MODELS SUGGEST IT WILL MOVE EAST OF THE MOUNTAINS BY 12Z FRIDAY. SYNOPTIC MODELS HAVE NOT HANDLE PCPN WELL TODAY. BASED POPS/WX ON THE HIGH RESOLUTION MODELS...ESPECIALLY THE HRRR AND THE WRFARW WHICH BRING SCATTERED SHOWERS ACROSS THE AREA THIS EVENING DIMINISHING OVERNIGHT WITH NO MENTION OF THUNDER. MEANTIME...ABUNDANT LOW LEVEL MOISTURE WITH NOT MUCH UPPER LEVEL SUPPORT SHOULD TRANSLATE INTO WIDESPREAD LOW LEVEL CLOUDS...AND PERHAPS DENSE FOG OVER HIGHER ELEVATIONS OVERNIGHT. THESE CLOUDS WILL STAND STRONG THROUGH AT LEAST 13Z BEFORE START TO DISSIPATE FRIDAY MORNING. THESE FEATURES ARE DEPICTED WITH HIGH CONFIDENCE BY THE SREF PROBABILITIES...AND NAM/RUC/GFS SOUNDING PROFILES. A SLIGHTLY DRIER AIRMASS FILTERS IN FROM THE NORTHWEST AS THE H85 FLOW BECOMES NORTHWEST AS SHOWN BY THE CMC/NAM/GFS/ECWF FRIDAY AFTERNOON...PERHAPS PUSHING EAST THE AFOREMENTIONED CLOUDS...AND SPREADING CLEARING FROM NORTHWEST TO SOUTHEAST FRIDAY EVENING. HOWEVER...A WEAK VORT MAX PASSES SOUTH OF THE AREA FRIDAY. KEPT LIKELY POPS ACROSS THE VIRGINIA COUNTIES FRIDAY AFTERNOON. WITH PLENTY OF CLOUDS OVERNIGHT...AND JUST A DEGREE CELSIUS LOWER THAN PREVIOUS NIGHT AT H850...EXPECT NO RADIATIONAL COOLING AND SLIGHTLY ABOVE NORMAL TEMPERATURES...EXCEPT FOR CRW...GENERALLY IN THE LOW 60S...RANGING TO THE MID 50S HIGHEST ELEVATIONS. THEREFORE...WENT WITH THE WARMER NUMBERS BETWEEN THE MET/MAV GUIDANCE FOR LOWS TONIGHT. HIGH ON FRIDAY WILL DEPEND ON HOW QUICKLY CLEARING SPREAD EAST SOUTHEAST. THEREFORE...KEEP HIGHER TEMPS ACROSS SOUTHEAST OH...GENERALLY IN THE MID 70S...RANGING INTO THE MID 60S HIGHEST ELEVATIONS. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... MODELS CONTINUING TO SHOW THE SURFACE FRONT HEADING SOUTH A BIT FASTER THAN SEVERAL RUNS AGO. NAM IS STILL A LITTLE FASTER...HAVING THE FRONT TO ATLANTIC COAST BY ABOUT 21Z FRI...WHILE GFS IS CLOSER TO 00Z SAT. DUE TO THIS...DRIED THINGS UP FASTER...LINGERING ONLY SLIGHT CHANCE POPS IN EXTREME SOUTHERN WV AND OUR VA COUNTIES SATURDAY NIGHT AS THE FINAL MOISTURE WITH THIS SYSTEM CLEARS OUT AND ONE FINAL VORT MAX SLIDES ACROSS TN/NC. ALSO DECREASED SKY COVER A LITTLE FASTER AS DRY AIR WORKS IN. THE NAM TRIES TO BRING SOME LOW/MID LEVEL MOISTURE BACK INTO THE MOUNTAINS ON SATURDAY...WHICH COMBINED WITH FALLING HEIGHTS AS THE NEXT UPPER LEVEL SYSTEM APPROACHES MAY BE ENOUGH FOR SOME DIURNALLY DRIVEN ISOLATED MOUNTAINS SHOWERS...HOWEVER GFS/ECMWF CONTINUE BRINGING DRY AIR...SO OPTED TO LEAVE ANY ISOLATED POPS OUT FOR NOW. MODELS SHOW THAT NEXT UPPER LOW DROPPING INTO SOUTHEASTERN MICHIGAN BY AROUND 12Z SUNDAY...WITH MOISTURE FLOW RIGHT OVER THE OHIO RIVER...SO DID BRING SLIGHT CHANCE POPS INTO NORTHWESTERN CWA BY 06-12Z SUN. WENT WITH A BLEND OF MAV/MET FOR HIGHS...PROVIDING ONLY SMALL CHANGES TO PREVIOUS FORECAST. OVERNIGHT LOWS A BIT TRICKIER...DEPENDING ON HOW FAST CLOUDS CLEAR BEHIND ONE SYSTEM...AND HOW QUICKLY HIGH CLOUDS MOVE BACK IN AHEAD OF THE NEXT. BLENDED WITH THE BIAS CORRECTED CONSENSUS GUIDANCE WHICH HAD A GOOD DEPICTION OF MID 50S ACROSS THE SOUTH FRIDAY NIGHT...WHERE CLOUDS WILL LINGER LONGEST...THEN CWA-WIDE MID TO UPPER 40S SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... MDLS ARE IN REASONABLY GOOD AGREEMENT WITH UPR LOW FCST TO DROP INTO THE EASTERN LAKES SUN-MON BEFORE LIFTING OUT. HAVE INCLUDED SOME CHC POPS FOR MAINLY DIURNAL SHRA ACROSS PORTIONS OF SE OH AND INTO N WV SUN AFTN WITH DRY SLOT KEEPING S AREAS DRY. SFC HIGH BUILDS IN FOR NEXT WEEK AS THE PATTERN RELAXES AND RIDGING TAKES HOLD ACROSS S HALF OF THE COUNTRY. SO AFTER INITIALLY COOL TEMPS...A WARMUP WILL BE NOTED DAYS 6 AND 7 UNDER WAA. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... A QUASI STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS WV THIS AFTERNOON AND TONIGHT...BEFORE MOVING EASTER OF THE MOUNTAINS BY 13Z. MOST SYNOPTIC MODELS SEEM TO BE OVERDOING SIGNIFICANT PCPN THIS AFTERNOON SPREADING EAST THROUGH TONIGHT. HIGH RESOLUTION MODELS LOOK MORE RELIABLE WITH ALOT LESS PCPN IN COVERAGE AND INTENSITY. THEREFORE...USED MAINLY WRFARW AND HRRR TO POPULATE POPS NOT MENTIONING THUNDER ANYWHERE AS SOUNDING PROFILE SHOW VERY LITTLE CAPE...LOW LAYERED SHEAR...AND PLENTY OF CLOUDS TO PREVENT ENOUGH HEATING FOR THUNDER. THEREFORE...VFR CONDITIONS EXPECTED THIS AFTERNOON...EXCEPT IFR DURING TEMPOS IN PKB AND CKB UNDER RAIN SHOWERS EARLY THROUGH AROUND 20Z. ALL MODELS SUGGEST ABUNDANT MOISTURE WILL SATURATE LOW LEVELS FOR IFR/LIFR CEILINGS ACROSS MOST SITES AFTER 06Z. VISIBILITIES WILL ALSO DECREASE TO IFR CRITERIA OVER ELEVATED TERRAIN OVERNIGHT. LOW STRATUS SHOULD REMAIN IN PLACE THROUGH AT LEAST 14Z...GRADUALLY LIFTING INTO 16Z LATE FRIDAY MORNING. AREAS WILL BECOME MVFR/VFR FROM WEST TO EAST FRIDAY AFTERNOON AS DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT. AN UPPER LEVEL WAVE COULD TRIGGER SOME CONVECTION ACROSS THE EXTREME SOUTHERN COAL FIELDS FRIDAY AFTERNOON. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: TIMING AND INTENSITY OF LOW STRATUS DEVELOPMENT AND DURATION MAY VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY M L M L M M M M M M L L HTS CONSISTENCY M L M M M M M M M M M M BKW CONSISTENCY H M M M M M M M M M M M EKN CONSISTENCY M M M M M M M M M H L M PKB CONSISTENCY M M M M M M M M M M H M CKB CONSISTENCY M M L L M M M M M M L L AFTER 18Z FRIDAY... OCCASIONAL IFR IN CEILINGS AND POSSIBLE SHOWERS OR DRIZZLE OVER SOUTHERN WEST VIRGINIA...THE MOUNTAINOUS COUNTIES OF WEST VIRGINIA...AND SOUTHWEST VIRGINIA FRIDAY AFTERNOON. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/30/CL NEAR TERM...ARJ SHORT TERM...MZ LONG TERM...30 AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
203 PM EDT THU SEP 27 2012 .SYNOPSIS... QUASI STATIONARY FRONT FINALLY MOVE EAST OF EASTERN MOUNTAINS FRIDAY MORNING. UPPER WAVE PASSES ACROSS THE SOUTH WITH AFTERNOON CONVECTION POSSIBLE. DRIER AIR MAKES INROADS SOUTH ON FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... ADJUSTED POPS CONCENTRATING HIGHER CHANCES ACROSS NORTHERN PORTIONS OF SOUTHEAST OH AND WV...PER RADAR IMAGES AND LATEST MODELS OUTPUT. HOWEVER...MODELS INSIST ON BRINGING MORE PCPN ACROSS THE SOUTHWEST...TO MOVE NORTHEAST ACROSS THE AREA THIS AFTERNOON AND EVENING. REMOVED THUNDER THROUGH AT LEAST 18Z PER LACK...DIURNAL HEATING...CAPE AND LOW DEEP LAYERED SHEAR. SOME STORMS CAN NOT BE RULED OUT THIS AFTERNOON AND EVENING. PREVIOUS DISCUSSION BELOW... BUSY GRAVEYARD SHIFT OVERNIGHT. ROUNDS OF SHOWERS/THUNDERSTORMS IN THE MOISTURE LADEN AIR FOR LATE SEPTEMBER. DEW POINTS AOA 60 DEGREES BECOMING COMMON ACROSS THE LOWLANDS. WITH THE LONGER NIGHTS...THERE ARE EVEN PATCHES OF FOG DRIFTING ABOUT...BOTH RAIN INDUCED NORTH...AND RADIATIONAL COOLING INDUCED SOUTH. THE HEAVIEST RAINS OVERNIGHT SEEMED TO FALL OVER NORTHERN GALLIA COUNTY INTO NORTHERN MASON AND SOUTHERN MEIGS. HAD SOME MEASURED AMOUNTS OF 1.6 INCHES SEEN. THAT WAS ONE OF OUR DRIEST AREAS PREVIOUS TO LAST NIGHT. WITH PRECIPITABLE WATER REMAINING IN THE 1.5 TO 1.6 INCH RANGE... WILL CONTINUE TO MONITOR RAIN AMOUNTS OVER PREVIOUSLY AFFECTED COUNTIES. AS OF 08Z...NO FLASH FLOOD WATCH POSTED. WAVE DEVELOPING SOUTH OF THE FRONT...BUT FRONT IS SAGGING SOUTH IN OHIO TO EVENTUALLY COMBINE WITH THE WAVE COMING OUT OF INDIANA NR 08Z. MOST NEAR TERM LOCAL MODELS KEEPING THE MAIN CONVECTION THIS MORNING IN OHIO. SO HAVE THE HIGHER POPS THAT WERE IN NORTH CENTRAL WV DURING THIS PREDAWN...LOWERING AS WE HAD FURTHER INTO THE MORE CIVILIZED HOURS OF THIS MORNING...WITH OUR HIGHER POPS IN SOUTHEAST OHIO. AS THE SURFACE WAVE HEADS EAST...WILL FINALLY PUSH THE HIGHER POPS INTO SOUTHERN WEST VIRGINIA DURING THE 15Z TO 20Z PERIOD. COULD NOT RULE OUT A FEW MORE STRONG TO SEVERE THUNDERSTORMS AHEAD OF THAT WAVE IN WEST VIRGINIA DURING THE AFTERNOON. WAS FASTER IN LOWERING THE CHANCES OF THUNDER LATE TODAY INTO THIS EVENING...SINCE WE ARE EXPECTING THE WIND SHIFT ASSOCIATED WITH THE SURFACE WAVE TO BE NEAR THE MASON-DIXON LING OF SW PA AND NRN WV ABOUND THE 21Z TODAY. HAVE CONSIDERABLE LOW LEVEL MOISTURE LINGERING THROUGH THE NIGHT...LINGERING SHOWERS MAY TURN TO DRIZZLE FOR THE WESTERN SLOPES AND MOUNTAIN COUNTIES...SAY EKN TO CRW TO BKW. HAVE IMPROVING CONDITIONS OVERNIGHT IN SOUTHEAST OHIO. TRIED TO HOLD DOWN TEMPERATURES IN THE WEST...BUT THINK AREAS LIKE EKN TO BKW COULD HAVE TIME TO GO HIGHER THAN SOUTHEAST OHIO. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... MODELS CONTINUING TO SHOW THE SURFACE FRONT HEADING SOUTH A BIT FASTER THAN SEVERAL RUNS AGO. NAM IS STILL A LITTLE FASTER...HAVING THE FRONT TO ATLANTIC COAST BY ABOUT 21Z FRI...WHILE GFS IS CLOSER TO 00Z SAT. DUE TO THIS...DRIED THINGS UP FASTER...LINGERING ONLY SLIGHT CHANCE POPS IN EXTREME SOUTHERN WV AND OUR VA COUNTIES SATURDAY NIGHT AS THE FINAL MOISTURE WITH THIS SYSTEM CLEARS OUT AND ONE FINAL VORT MAX SLIDES ACROSS TN/NC. ALSO DECREASED SKY COVER A LITTLE FASTER AS DRY AIR WORKS IN. THE NAM TRIES TO BRING SOME LOW/MID LEVEL MOISTURE BACK INTO THE MOUNTAINS ON SATURDAY...WHICH COMBINED WITH FALLING HEIGHTS AS THE NEXT UPPER LEVEL SYSTEM APPROACHES MAY BE ENOUGH FOR SOME DIURNALLY DRIVEN ISOLATED MOUNTAINS SHOWERS...HOWEVER GFS/ECMWF CONTINUE BRINGING DRY AIR...SO OPTED TO LEAVE ANY ISOLATED POPS OUT FOR NOW. MODELS SHOW THAT NEXT UPPER LOW DROPPING INTO SOUTHEASTERN MICHIGAN BY AROUND 12Z SUNDAY...WITH MOISTURE FLOW RIGHT OVER THE OHIO RIVER...SO DID BRING SLIGHT CHANCE POPS INTO NORTHWESTERN CWA BY 06-12Z SUN. WENT WITH A BLEND OF MAV/MET FOR HIGHS...PROVIDING ONLY SMALL CHANGES TO PREVIOUS FORECAST. OVERNIGHT LOWS A BIT TRICKIER...DEPENDING ON HOW FAST CLOUDS CLEAR BEHIND ONE SYSTEM...AND HOW QUICKLY HIGH CLOUDS MOVE BACK IN AHEAD OF THE NEXT. BLENDED WITH THE BIAS CORRECTED CONSENSUS GUIDANCE WHICH HAD A GOOD DEPICTION OF MID 50S ACROSS THE SOUTH FRIDAY NIGHT...WHERE CLOUDS WILL LINGER LONGEST...THEN CWA-WIDE MID TO UPPER 40S SATURDAY NIGHT. && .LONG TERM /SUNDAY THROUGH THURSDAY/... MDLS ARE IN REASONABLY GOOD AGREEMENT WITH UPR LOW FCST TO DROP INTO THE EASTERN LAKES SUN-MON BEFORE LIFTING OUT. HAVE INCLUDED SOME CHC POPS FOR MAINLY DIURNAL SHRA ACROSS PORTIONS OF SE OH AND INTO N WV SUN AFTN WITH DRY SLOT KEEPING S AREAS DRY. SFC HIGH BUILDS IN FOR NEXT WEEK AS THE PATTERN RELAXES AND RIDGING TAKES HOLD ACROSS S HALF OF THE COUNTRY. SO AFTER INITIALLY COOL TEMPS...A WARMUP WILL BE NOTED DAYS 6 AND 7 UNDER WAA. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... A QUASI STATIONARY FRONTAL BOUNDARY WILL MEANDER ACROSS WV THIS AFTERNOON AND TONIGHT...BEFORE MOVING EASTER OF THE MOUNTAINS BY 13Z. MOST SYNOPTIC MODELS SEEM TO BE OVERDOING SIGNIFICANT PCPN THIS AFTERNOON SPREADING EAST THROUGH TONIGHT. HIGH RESOLUTION MODELS LOOK MORE RELIABLE WITH ALOT LESS PCPN IN COVERAGE AND INTENSITY. THEREFORE...USED MAINLY WRFARW AND HRRR TO POPULATE POPS NOT MENTIONING THUNDER ANYWHERE AS SOUNDING PROFILE SHOW VERY LITTLE CAPE...LOW LAYERED SHEAR...AND PLENTY OF CLOUDS TO PREVENT ENOUGH HEATING FOR THUNDER. THEREFORE...VFR CONDITIONS EXPECTED THIS AFTERNOON...EXCEPT IFR DURING TEMPOS IN PKB AND CKB UNDER RAIN SHOWERS EARLY THROUGH AROUND 20Z. ALL MODELS SUGGEST ABUNDANT MOISTURE WILL SATURATE LOW LEVELS FOR IFR/LIFR CEILINGS ACROSS MOST SITES AFTER 06Z. VISIBILITIES WILL ALSO DECREASE TO IFR CRITERIA OVER ELEVATED TERRAIN OVERNIGHT. LOW STRATUS SHOULD REMAIN IN PLACE THROUGH AT LEAST 14Z...GRADUALLY LIFTING INTO 16Z LATE FRIDAY MORNING. AREAS WILL BECOME MVFR/VFR FROM WEST TO EAST FRIDAY AFTERNOON AS DRIER AIRMASS MOVES IN BEHIND THE COLD FRONT. AN UPPER LEVEL WAVE COULD TRIGGER SOME CONVECTION ACROSS THE EXTREME SOUTHERN COAL FIELDS FRIDAY AFTERNOON. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: LOW. ALTERNATE SCENARIOS: TIMING AND INTENSITY OF LOW STRATUS DEVELOPMENT AND DURATION MAY VARY. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY M L M L M M M M M M L L HTS CONSISTENCY M L M M M M M M M M M M BKW CONSISTENCY H M M M M M M M M M M M EKN CONSISTENCY M M M M M M M M M H L M PKB CONSISTENCY M M M M M M M M M M H M CKB CONSISTENCY M M L L M M M M M M L L AFTER 18Z FRIDAY... OCCASIONAL IFR IN CEILINGS AND POSSIBLE SHOWERS OR DRIZZLE OVER SOUTHERN WEST VIRGINIA...THE MOUNTAINOUS COUNTIES OF WEST VIRGINIA...AND SOUTHWEST VIRGINIA FRIDAY AFTERNOON. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...KTB/ARJ SHORT TERM...MZ LONG TERM...30 AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
634 AM EDT THU SEP 27 2012 .SYNOPSIS... A WAVE OF LOW PRESSURE TRAVELING ALONG A SLOW MOVING FRONTAL BOUNDARY WILL BRING WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS TODAY. THE BOUNDARY WILL MOVE SOUTH OF THE OHIO RIVER TONIGHT FOLLOWED BY HIGH PRESSURE AND DRIER AIR FOR FRIDAY. LOW PRESSURE IN THE UPPER ATMOSPHERE WILL PROVIDE CLOUDS AND POSSIBLY A FEW SHOWERS OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A COLD FRONT IS SAGGING SLOWLY SOUTH THROUGH OHIO. A WAVE OF LOW PRESSURE TRAVELING ALONG THE FRONT IS DEPICTED RATHER WELL ON THE NAM AND RAP MODELS WHICH SHOW THE WAVE CROSSING THE ILN AREA TODAY. THIS WILL BRING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS FOR MOST OF THE FORECAST AREA...AND CURRENT RADAR TRENDS SUPPORT THIS SCENARIO. WENT WITH CATEGORICAL POPS FOR MUCH OF THE AREA...DECREASING TO CHANCE FROM WEST TO EAST DURING THE AFTERNOON. THE LACK OF INSTABILITY SHOULD KEEP ANY THUNDERSTORMS THAT FORM BELOW SEVERE LIMITS. TEMPERATURES SHOULD TOP OUT AROUND 70 THIS AFTERNOON...THOUGH THERE IS A GREAT DEAL OF UNCERTAINTY WITH RESPECT TO TEMPERATURES DUE TO CLOUDS...PRECIPITATION...AND FRONTAL POSITION. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... MODELS NOW SHOW THE FRONT DROPPING FARTHER SOUTH THAN WAS PREVIOUSLY INDICATED. THEREFORE...WENT WITH A DRY FORECAST FROM LATE TONIGHT THROUGH FRIDAY NIGHT AS HIGH PRESSURE AND DRIER AIR WORK IN FROM THE NORTH. A DEEP CUT OFF UPPER LOW WILL BE MOVING SOUTH FROM CANADA TOWARD THE ILN AREA ON SATURDAY. MOISTURE ASSOCIATED WITH THE SYSTEM SHOULD STAY MAINLY TO THE NORTH...BUT CLOUDS WILL PROBABLY INCREASE AND ISOLATED SHOWERS MAY AFFECT NORTHERN COUNTIES SATURDAY AFTERNOON. HIGH TEMPERATURES ARE EXPECTED TO BE AROUND 70 BOTH FRIDAY AND SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MODELS ARE IN CLOSE AGREEMENT THROUGH THE PERIOD. FOR SUNDAY...FOCUSED ON TROUGH ACROSS THE AREA WITH DISTURBANCE ROTATING THRU. TIMING OF THIS DISTURBANCE IS MAIN PROBLEM WITH GFS MORE SAT NIGHT AND ECMWF MORE SUN. HAVE OPTED FOR SMALL POP ACROSS THE NORTH FOR BOTH SCENARIOS FOR NOW. LATER FCST CAN PERHAPS HAVE BETTER HANDLE ON TIMING. MON-WED WILL SEE RIDGING WITH WARMING THRU PERIOD. SEASONABLY COOL MORNINGS WITH SEASONAL OR SLIGHTLY ABOVE NORMAL DAYTIME HIGHS. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... IN SPLIT FLOW PATTERN S/W OVER SRN ILLINOIS TO RIPPLE EAST THRU THE OHIO VALLEY THIS MORNING. NUMERICAL MODEL SOLNS IN BETTER AGREEMENT WITH ASSOCIATED SFC LOW TRACKING EAST THRU SRN OHIO ALONG A SLOW MOVING E-W ORIENTED SFC FRONTAL BOUNDARY. AREA OF SHOWERS TO CONTINUE TO AFFECT THE TAF SITES THIS MORNING IN A REGION OF FAVORABLE 925 MB CONVERGENCE. THEREFORE...WILL ALLOW FOR A PERIOD OF SHOWERS THIS MORNING WITH CIGS/VSBYS DROPPING INTO MVFR CATEGORY. WITH THE PASSAGE OF THIS SFC WAVE...THE FRONTAL BOUNDARY WILL SINK SLOWLY SOUTH OF THE TAF SITES BY LATE AFTN. EXPECT TO SEE CIGS IMPROVE THIS EVENING TO VFR BUT SOME BR DEVELOPMENT WILL BE POSSIBLE. DEGREE AND TIMING FOR PARTIAL CLEARING OVERNIGHT IS IN QUESTION ESPECIALLY ACRS THE SRN TAF SITES CLOSER TO THE FRONTAL BOUNDARY. THEREFORE...HAVE LIMITED VSBY RESTRICTIONS TO MVFR CATEGORY AT THIS TIME BUT WITH LIGHT WINDS AND WET GROUND IFR VSBYS WILL BE POSSIBLE. .OUTLOOK...MVFR CONDITIONS POSSIBLE SUNDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...CONIGLIO NEAR TERM...CONIGLIO SHORT TERM...CONIGLIO LONG TERM...PADGETT AVIATION...RANDALL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
436 AM EDT THU SEP 27 2012 .SYNOPSIS... A WAVE OF LOW PRESSURE TRAVELING ALONG A SLOW MOVING FRONTAL BOUNDARY WILL BRING WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS TODAY. THE BOUNDARY WILL MOVE SOUTH OF THE OHIO RIVER TONIGHT FOLLOWED BY HIGH PRESSURE AND DRIER AIR FOR FRIDAY. LOW PRESSURE IN THE UPPER ATMOSPHERE WILL PROVIDE CLOUDS AND POSSIBLY A FEW SHOWERS OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A COLD FRONT IS SAGGING SLOWLY SOUTH THROUGH OHIO. A WAVE OF LOW PRESSURE TRAVELING ALONG THE FRONT IS DEPICTED RATHER WELL ON THE NAM AND RAP MODELS WHICH SHOW THE WAVE CROSSING THE ILN AREA TODAY. THIS WILL BRING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS FOR MOST OF THE FORECAST AREA...AND CURRENT RADAR TRENDS SUPPORT THIS SCENARIO. WENT WITH CATEGORICAL POPS FOR MUCH OF THE AREA...DECREASING TO CHANCE FROM WEST TO EAST DURING THE AFTERNOON. THE LACK OF INSTABILITY SHOULD KEEP ANY THUNDERSTORMS THAT FORM BELOW SEVERE LIMITS. TEMPERATURES SHOULD TOP OUT AROUND 70 THIS AFTERNOON...THOUGH THERE IS A GREAT DEAL OF UNCERTAINTY WITH RESPECT TO TEMPERATURES DUE TO CLOUDS...PRECIPITATION...AND FRONTAL POSITION. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/... MODELS NOW SHOW THE FRONT DROPPING FARTHER SOUTH THAN WAS PREVIOUSLY INDICATED. THEREFORE...WENT WITH A DRY FORECAST FROM LATE TONIGHT THROUGH FRIDAY NIGHT AS HIGH PRESSURE AND DRIER AIR WORK IN FROM THE NORTH. A DEEP CUT OFF UPPER LOW WILL BE MOVING SOUTH FROM CANADA TOWARD THE ILN AREA ON SATURDAY. MOISTURE ASSOCIATED WITH THE SYSTEM SHOULD STAY MAINLY TO THE NORTH...BUT CLOUDS WILL PROBABLY INCREASE AND ISOLATED SHOWERS MAY AFFECT NORTHERN COUNTIES SATURDAY AFTERNOON. HIGH TEMPERATURES ARE EXPECTED TO BE AROUND 70 BOTH FRIDAY AND SATURDAY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MODELS ARE IN CLOSE AGREEMENT THROUGH THE PERIOD. FOR SUNDAY...FOCUSED ON TROUGH ACROSS THE AREA WITH DISTURBANCE ROTATING THRU. TIMING OF THIS DISTURBANCE IS MAIN PROBLEM WITH GFS MORE SAT NIGHT AND ECMWF MORE SUN. HAVE OPTED FOR SMALL POP ACROSS THE NORTH FOR BOTH SCENARIOS FOR NOW. LATER FCST CAN PERHAPS HAVE BETTER HANDLE ON TIMING. MON-WED WILL SEE RIDGING WITH WARMING THRU PERIOD. SEASONABLY COOL MORNINGS WITH SEASONAL OR SLIGHTLY ABOVE NORMAL DAYTIME HIGHS. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... IN SPLIT FLOW PATTERN S/W OVER THE MID MS VLY TO RIPPLE EAST THRU THE OHIO VALLEY THIS MORNING. NUMERICAL MODEL SOLNS IN BETTER AGREEMENT WITH ASSOCIATED SFC LOW TO TRACK E INTO SW OHIO ALONG A SLOW MOVING E-W ORIENTED SFC FRONTAL BOUNDARY. AREA OF SHOWERS AND THUNDERSTORMS TO EXPAND NORTH ACRS THE TAF SITES THIS MORNING IN A REGION OF FAVORABLE 925 MB CONVERGENCE. WILL ALLOW FOR A PERIOD OF SHOWERS AND THUNDERSTORMS THIS MORNING WITH CIGS DROPPING INTO MVFR CATEGORY. WITH THE PASSAGE OF THIS SFC WAVE THE FRONTAL BOUNDARY WILL SINK SLOWLY SOUTH OF THE TAF SITES BY LATE AFTN. EXPECT TO SEE CIGS IMPROVE THIS EVENING TO VFR BUT SOME BR DEVELOPMENT WILL BE POSSIBLE. HAVE LIMITED RESTRICTION TO MVFR AT THIS TIME. .OUTLOOK...MVFR CONDITIONS POSSIBLE SUNDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...CONIGLIO NEAR TERM...CONIGLIO SHORT TERM...CONIGLIO LONG TERM...PADGETT AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
131 AM EDT THU SEP 27 2012 .SYNOPSIS... A SLOW MOVING FRONTAL BOUNDARY WILL GRADUALLY MOVE THROUGH THE OHIO VALLEY THIS WEEK. SOUTH OF THE FRONT...SHOWERS AND THUNDERSTORMS WILL CONTINUE TO IMPACT THE REGION. HIGH PRESSURE WILL BUILD IN ON SATURDAY...BUT AN UPPER LEVEL LOW PRESSURE CENTER WILL PROVIDE A CHANCE OF SHOWERS ON SUNDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... TRIED TO REMOVE SHOWERS IN THE I-70 CORRIDOR WEST OF COLUMBUS AND NOTED THAT PATCHY DENSE FOG IS BEING REPORTED WHERE SKY COVER ALLOWS RADIATIONAL COOLING TO LOWER TEMPS TO THE ALREADY MOIST LOWER LAYER OF THE ATMOSPHERE. DO NOT EXPECT THE FOG TO REMAIN FOR THE ENTIRE OVERNIGHT AS UPSTREAM CLOUD COVER WILL HAMPER THE DROP IN TEMPERATURES AND VSBYS SHOULD WAFFLE FOR A COUPLE OF HOURS THROUGH DAYBREAK. ANY CHANCES OF SHOWERS NORTH OF THE METRO CINCY AREA SHOULD NOT SEE A CHANCE OF THUNDER FOR THE REMAINDER OF THE NIGHT...I DID NOT ADJUST FORECAST BEYOND DAYBREAK BUT EXPECT THAT THE ELEVATED INSTABILITY WILL BE LIMITED IN THIS AREA TOMORROW AS WELL. PREVIOUS DISCUSSION BELOW. SOUTH OF A SLOWLY-MOVING COLD FRONT...THE CWA REMAINS ENTRENCHED IN AN AREA OF DEEP MOISTURE AND MODERATE WEST-SOUTHWESTERLY FLOW IN THE LOWER TO MID LEVELS. THE PRIMARY FORECAST FOCUS IS ON CONVECTIVE CHANCES AND TIMING TONIGHT. CONVECTION ONGOING ACROSS THE CWA APPEARS TO BE ASSOCIATED WITH A WEAK VORTICITY CENTER OVER INDIANA...WITH THE NEW DEVELOPMENT FIRING UP ON A BAND WELL OUT AHEAD OF IT. MEANWHILE...THE WSW-ENE ORIENTED BAND OF SHOWERS (WITH EMBEDDED THUNDER) THROUGH CENTRAL OHIO IS JUST AHEAD OF THE BOUNDARY. INSTABILITY HAS BUILT TO ABOUT 1000 J/KG IN NORTHERN KENTUCKY...AND IS GREATER FURTHER TO THE SOUTHWEST. RUC13 INSTABILITY FORECASTS OF 2000-2500 J/KG ARE MUCH TOO HIGH...GIVEN THE ERRONEOUS ADVECTION OF DEWPOINTS OVER 70 DEGREES INTO SW OHIO. POPS ARE CATEGORICAL FOR THE FIRST FEW HOURS OF THE FORECAST...AS THE CURRENT ACTIVITY WORKS ITS WAY THROUGH THE CWA. AFTER THAT...MUCH OF THE CWA MAY SEE A BREAK FROM CONVECTIVE POTENTIAL...IN THE WAKE OF THE AFTERNOON SYSTEM. WHERE INSTABILITY IS GREATER IN THE SOUTH...ADDITIONAL DEVELOPMENT IS POSSIBLE. GIVEN THE 40 KNOTS OF 0-3 KM SHEAR (WHICH IS ACTUALLY STRONGER THAN THE 0-6 KM SHEAR)...SOME STORM ORGANIZATION AND A FEW STRONG CELLS WILL BE POSSIBLE. WITHOUT A KEY TRIGGER OR MUCH INSTABILITY...WIDESPREAD SEVERE WEATHER DOES NOT APPEAR POSSIBLE. POPS WILL BE KEPT IN THE LIKELY CATEGORY FOR THE SOUTHEASTERN TWO THIRDS OF THE CWA GOING INTO TONIGHT. HOWEVER...GIVEN THE LACK OF PRECIPITATION BEHIND THE CURRENT INDIANA/OHIO SYSTEM...IT APPEARS THAT THE ACTIVITY WILL BE SHOWERY AND NOT ALL OF IT WILL BE CONVECTIVE. DEVELOPING STORMS IN SOUTHERN ILLINOIS MAY BE WHAT ENDS UP PROVIDING A GREATER CHANCE OF PRECIPITATION LATER ON TONIGHT. THE HOLES IN THE CLOUD COVER ALLOWED THE SOUTHERN CWA TO APPROACH 80 DEGREES TODAY. GIVEN THE WARMER STARTING POINT...AND EXPECTED MOIST AND CLOUDY ATMOSPHERE TONIGHT...MIN TEMPS IN THE SOUTH WERE BUMPED UP A FEW DEGREES FROM THE PREVIOUS FORECAST. WITH THE FRONT MOVING INTO THE AREA...AND COLD ADVECTION BEGINNING IN THE NORTH...THE TEMPERATURE GRADIENT OVERNIGHT WILL BE SOMEWHAT TIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/... THE FRONTAL BOUNDARY WILL CONTINUE TO MAKE VERY SLOW PROGRESS TO THE EAST ON THURSDAY...BUT ENOUGH PROGRESS TO BRING AN END TO ANY SIGNIFICANT CHANCES OF PRECIPITATION. THE FRONT WILL ORIENT ITSELF EAST-TO-WEST ACROSS KENTUCKY...AND STALL OUT THROUGH FRIDAY. THIS MEANS THAT THE MOISTURE AND FORCING ASSOCIATED WITH THE FRONT WILL BE VERY CLOSE TO THE SOUTHERN EDGE OF THE FORECAST AREA. THIS WILL REQUIRE A CHANCE OF SHOWERS (WITH A POSSIBILITY OF THUNDERSTORMS) IN THE SOUTHERN HALF OF THE CWA FOR THURSDAY...AND THEN JUST THE SOUTHERN THIRD OF THE CWA ON FRIDAY. AS THE VARIOUS MODELS (AND THEIR VARIOUS RUNS) CONTINUE TO STRUGGLE WITH TIMING THE EMBEDDED DISTURBANCES IN THE QUICK LOWER-TO-MID-LEVEL FLOW...IT REMAINS DIFFICULT TO PIN DOWN THE TIME OR PLACEMENT OF ANY NORTHWARD-IMPINGING CONVECTIVE SYSTEMS THAT MAY IMPACT THE CWA DURING THIS TIME FRAME. MAX TEMPERATURES WERE ADJUSTED SLIGHTLY DOWN THROUGH THE END OF THE WEEK...AS THE COLD ADVECTION BEHIND THE FRONT WILL KEEP TEMPS FROM REACHING 70. THE TEMPERATURE GRADIENT WILL BE TIGHTER ON THURSDAY...WITH THE FRONT STILL IN THE AREA. GUIDANCE AND MODEL NUMBERS EXHIBITED LITTLE SPREAD...INCREASING CONFIDENCE IN THE FORECAST. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... MODELS ARE IN CLOSE AGREEMENT THROUGH THE PERIOD. SAT AND SUN FOCUSED ON TROUGH ACROSS THE AREA WITH DISTURBANCE ROTATING THRU. TIMING OF THIS DISTURBANCE IS MAIN PROBLEM WITH GFS MORE SAT NIGHT AND ECMWF MORE SUN. HAVE OPTED FOR SMALL POP ACROSS THE NORTH FOR BOTH SCENARIOS FOR NOW. LATER FCST CAN PERHAPS HAVE BETTER HANDLE ON TIMING. MON-WED WILL SEE RIDGING WITH WARMING THRU PERIOD. SEASONABLY COOL MORNINGS WITH SEASONAL OR SLIGHTLY ABOVE NORMAL DAYTIME HIGHS. && .AVIATION /05Z THURSDAY THROUGH MONDAY/... IN SPLIT FLOW PATTERN S/W OVER THE MID MS VLY TO RIPPLE EAST THRU THE OHIO VALLEY THIS MORNING. NUMERICAL MODEL SOLNS IN BETTER AGREEMENT WITH ASSOCIATED SFC LOW TO TRACK E INTO SW OHIO ALONG A SLOW MOVING E-W ORIENTED SFC FRONTAL BOUNDARY. AREA OF SHOWERS AND THUNDERSTORMS TO EXPAND NORTH ACRS THE TAF SITES THIS MORNING IN A REGION OF FAVORABLE 925 MB CONVERGENCE. WILL ALLOW FOR A PERIOD OF SHOWERS AND THUNDERSTORMS THIS MORNING WITH CIGS DROPPING INTO MVFR CATEGORY. WITH THE PASSAGE OF THIS SFC WAVE THE FRONTAL BOUNDARY WILL SINK SLOWLY SOUTH OF THE TAF SITES BY LATE AFTN. EXPECT TO SEE CIGS IMPROVE THIS EVENING TO VFR BUT SOME BR DEVELOPMENT WILL BE POSSIBLE. HAVE LIMITED RESTRICTION TO MVFR AT THIS TIME. .OUTLOOK...MVFR CONDITIONS POSSIBLE SUNDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...FRANKS/HATZOS SHORT TERM...HATZOS LONG TERM...PADGETT AVIATION...AR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
342 AM EDT THU SEP 27 2012 .SYNOPSIS... A SLOW MOVING COLD FRONT OVER NORTHWEST PENNSYLVANIA EARLY THIS MORNING WILL DRIFT SOUTH ACROSS THE STATE OVERNIGHT AND BECOME LOCATED NEAR THE PENNSYLVANIA...MARYLAND BORDER LATER TODAY WHERE IT WILL STALL OUT RIGHT INTO FRIDAY. THE CLOSE PROXIMITY OF THIS FRONT WILL MAINTAIN THE THREAT OF OCCASIONAL RAIN OVER THE SOUTHERN THIRD OF THE KEYSTONE STATE FOR THURSDAY AND FRIDAY. A DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHWARD FROM EASTERN CANADA AND CARVE OUT OVER THE GREAT LAKES REGION AND NORTHEAST STATES THIS WEEKEND. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... VERY SLOW SEWD DRIFTING COLD FRONT NOW LOCATED FROM 20S KCLE ENE THROUGH KGKJ NEWD THROUGH WARREN AND KELZ THIS HOUR. TO THE SOUTH... SCATTERED SHOWERS ARE BEING MAINTAINED IN THE COUPLED JET REGION BETWEEN A 65-70KT 250 KT JET OVER SOUTHWEST PA AND A 90KT 250MB JET EXITING THE CENTRAL NEW ENGLAND COAST. RADAR OBSERVATIONS AND MODEL DIAGNOSTICS OF EPV INDICATE SOME CSI BANDING OVER THE WEST CENTRAL MOUNTAINS WHICH WILL BRING SOME LOCALLY HIGHER RAINFALL AMOUNTS IN THESE AREAS AND POINTS EASTWARD. POOL OF DEEPEST LAYER MOISTURE LIES ALONG THIS AXIS FROM SOUTHEAST OHIO EASTWARD ALONG AND NORTH OF THE PA TURNPIKE. ELONGATED 5H SHORTWAVE AXIS DROPPING SOUTHWARD TOWARDS THE MASON DIXON LINE IS MAINTAINING A LINE OF THUNDERSTORMS FROM THE IN/KY BORDER NORTHEASTWARD TO WESTERN AND NORTHERN WV...WHICH MAY GRAZE AREAS OF THE SOUTH CENTRAL MOUNTAINS AND LOWER SUSQ RIVER VALLEY ALONG THE MARYLAND BORDER OVERNIGHT. LATEST NAM AND RUC DEPICT THIS WELL...TARGETING SWRN AND SCENT COUNTIES OF THE CWA AFTER 06Z WITH THE EXPANDING AREA OF SHOWERS. THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING STATIONARY THERE THROUGH THURSDAY NIGHT. A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3 TENTHS ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS OF THE STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS POSSIBLY SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS THE NRN MTNS. SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER 50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 AM FRIDAY/... FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH. THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S. MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... THE UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED STATES WILL LIFT OUT ON FRIDAY IN FAVOR OF A STRONGER UPPER TROF DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND CUTTING OFF OVER THE CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY AND SUNDAY. THIS WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE REGION ON FRIDAY AND FRIDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS RETURN FOR LATER SATURDAY AND ESPECIALLY SUNDAY OVER CENTRAL PA. THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE THIS WEEK AND THIS WEEKEND. BOTH THE GFS AND EC SHIFT FOCUS OF HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE UPPER LOW IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT LAKES. WHILE UNSETTLED CONDITIONS WILL PERSIST THROUGH THE WEEKEND AND INTO MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE EAST COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL APPEARS LOW...AS THE OFFSHORE RICH MOISTURE PLUME FEEDING NORTHWARD TO EASTERN NEW ENGLAND DOES NOT EFFECTIVELY PHASE WITH THE DEVELOPING GREAT LAKES CUTOFF. AS A RESULT...QPF SHOULD BE GENERALLY SPEAKING ON THE LIGHT SIDE AS OPPOSED TO SOAKING. WETTEST AREAS WILL BE THE NORTHWEST AND NORTHERN TIER COUNTIES CLOSEST TO THE PROXIMITY OF THE CUTOFF. LAST 2-3 MODEL CYCLES HAVE INDICATED A POSSIBLE RETURN TO DRIER CONDITIONS FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY ACROSS THE OHIO VALLEY AND INTO PA. WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... A FRONTAL BOUNDARY WILL PUSH SLOWLY SOUTHWARD ACROSS NORTHERN PA EARLY THIS MORNING. WEAK UPPER-LEVEL DISTURBANCES TRANSLATING EWD FM THE OH VLY WILL CONTINUE TO SUPPORT SHOWERS ACRS THE SRN 1/2 OF PA. BASED ON LATEST COSPA AND RADAR TRENDS...WILL KEEP MENTION OF RAIN FOR SOUTH-CENTRAL TAF SITES THRU APPROX 12Z...FOLLOWED BY A RELATIVE LULL IN PCPN FOR MID-LATE MORNING. FROPA SHOULD OCCUR AT BFD BEFORE 08Z AND SHIFT WINDS TO THE NORTH...ALLOWING DRY AIR TO IMPROVE CIGS/VIS TO MVFR. VFR TO MVFR CONDS SHOULD BE COMMON OVR THE REMAINING AIRFIELDS. THE FRONTAL BOUNDARY WILL STALL OUT OVR SRN PA THIS AFTN...AND CONTINUE TO ACT AS A CONDUIT FOR SHOWER ACTIVITY. THERE IS A RATHER SIGNIFICANT FCST CHANGE LOOMING ON THE HORIZON BASED ON THE LATEST MODEL DATA...WHICH SUGGESTS MORE WIDESPREAD PCPN ACRS THE AREA THRU TONIGHT. WILL ADDRESS THIS CHANGE IN SUBSEQUENT TAF SETS. OUTLOOK... FRI-SAT...MVFR-IFR BCMG MVFR-VFR. SUN-MON...SCT SHOWERS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DEVOIR/LAMBERT NEAR TERM...DEVOIR/LAMBERT SHORT TERM...DANGELO LONG TERM...DEVOIR/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
203 AM EDT THU SEP 27 2012 .SYNOPSIS... A SLOW MOVING COLD FRONT OVER NORTHWEST PENNSYLVANIA EARLY THIS MORNING WILL DRIFT SOUTH ACROSS THE STATE OVERNIGHT AND BECOME LOCATED NEAR THE PENNSYLVANIA...MARYLAND BORDER LATER TODAY WHERE IT WILL STALL OUT RIGHT INTO FRIDAY. THE CLOSE PROXIMITY OF THIS FRONT WILL MAINTAIN THE THREAT OF OCCASIONAL RAIN OVER THE SOUTHERN THIRD OF THE KEYSTONE STATE FOR THURSDAY AND FRIDAY. A DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHWARD FROM EASTERN CANADA AND CARVE OUT OVER THE GREAT LAKES REGION AND NORTHEAST STATES THIS WEEKEND. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... VERY SLOW SEWD DRIFTING COLD FRONT NOW LOCATED FROM 20S KCLE ENE THROUGH KGKJ NEWD THROUGH WARREN AND KELZ THIS HOUR. TO THE SOUTH... SCATTERED SHOWERS ARE BEING MAINTAINED IN THE COUPLED JET REGION BETWEEN A 65-70KT 250 KT JET OVER SOUTHWEST PA AND A 90KT 250MB JET EXITING THE CENTRAL NEW ENGLAND COAST. RADAR OBSERVATIONS AND MODEL DIAGNOSTICS OF EPV INDICATE SOME CSI BANDING OVER THE WEST CENTRAL MOUNTAINS WHICH WILL BRING SOME LOCALLY HIGHER RAINFALL AMOUNTS IN THESE AREAS AND POINTS EASTWARD. POOL OF DEEPEST LAYER MOISTURE LIES ALONG THIS AXIS FROM SOUTHEAST OHIO EASTWARD ALONG AND NORTH OF THE PA TURNPIKE. ELONGATED 5H SHORTWAVE AXIS DROPPING SOUTHWARD TOWARDS THE MASON DIXON LINE IS MAINTAINING A LINE OF THUNDERSTORMS FROM THE IN/KY BORDER NORTHEASTWARD TO WESTERN AND NORTHERN WV...WHICH MAY GRAZE AREAS OF THE SOUTH CENTRAL MOUNTAINS AND LOWER SUSQ RIVER VALLEY ALONG THE MARYLAND BORDER OVERNIGHT. LATEST NAM AND RUC DEPICT THIS WELL...TARGETING SWRN AND SCENT COUNTIES OF THE CWA AFTER 06Z WITH THE EXPANDING AREA OF SHOWERS. THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING STATIONARY THERE THROUGH THURSDAY NIGHT. A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3 TENTHS ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS OF THE STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS POSSIBLY SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS THE NRN MTNS. SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER 50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/... FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH. THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S. MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED STATES WILL LIFT OUT THURSDAY NIGHT AND FRIDAY IN FAVOR OF A STRONGER UPPER TROF DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND CUTTING OFF OVER THE CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY AND SUNDAY. THIS WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE REGION ON THURSDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS RETURN FOR LATER SATURDAY AND SUNDAY OVER CENTRAL PA. THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE THIS WEEK AND THIS WEEKEND...ALSO...BOTH THE GFS AND EC SHIFT FOCUS OF HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE UPPER LOW IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT LAKES. WHILE UNSETTLED WILL PERSIST THROUGH THE WEEKEND AND INTO MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE EAST COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL APPEARS LOW. CURRENT MODEL SOLUTIONS SHOW A POSSIBLE RETURN TO DRIER CONDITIONS FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY ACROSS THE OHIO VALLEY AND INTO PA. WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... A FRONTAL BOUNDARY WILL PUSH SLOWLY SOUTHWARD ACROSS NORTHERN PA EARLY THIS MORNING. WEAK UPPER-LEVEL DISTURBANCES TRANSLATING EWD FM THE OH VLY WILL CONTINUE TO SUPPORT SHOWERS ACRS THE SRN 1/2 OF PA. BASED ON LATEST COSPA AND RADAR TRENDS...WILL KEEP MENTION OF RAIN FOR SOUTH-CENTRAL TAF SITES THRU APPROX 12Z...FOLLOWED BY A RELATIVE LULL IN PCPN FOR MID-LATE MORNING. FROPA SHOULD OCCUR AT BFD BEFORE 08Z AND SHIFT WINDS TO THE NORTH...ALLOWING DRY AIR TO IMPROVE CIGS/VIS TO MVFR. VFR TO MVFR CONDS SHOULD BE COMMON OVR THE REMAINING AIRFIELDS. THE FRONTAL BOUNDARY WILL STALL OUT OVR SRN PA THIS AFTN...AND CONTINUE TO ACT AS A CONDUIT FOR SHOWER ACTIVITY. THERE IS A RATHER SIGNIFICANT FCST CHANGE LOOMING ON THE HORIZON BASED ON THE LATEST MODEL DATA...WHICH SUGGESTS MORE WIDESPREAD PCPN ACRS THE AREA THRU TONIGHT. WILL ADDRESS THIS CHANGE IN SUBSEQUENT TAF SETS. OUTLOOK... FRI-SAT...MVFR-IFR BCMG MVFR-VFR. SUN-MON...SCT SHOWERS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/LAMBERT NEAR TERM...DEVOIR/LAMBERT SHORT TERM...DANGELO LONG TERM...DEVOIR/GARTNER AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1258 AM EDT THU SEP 27 2012 .SYNOPSIS... A SLOW MOVING COLD FRONT OVER NORTHWEST PENNSYLVANIA EARLY THIS MORNING WILL DRIFT SOUTH ACROSS THE STATE OVERNIGHT AND BECOME LOCATED NEAR THE PENNSYLVANIA...MARYLAND BORDER LATER TODAY WHERE IT WILL STALL OUT RIGHT INTO FRIDAY. THE CLOSE PROXIMITY OF THIS FRONT WILL MAINTAIN THE THREAT OF OCCASIONAL RAIN OVER THE SOUTHERN THIRD OF THE KEYSTONE STATE FOR THURSDAY AND FRIDAY. A DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHWARD FROM EASTERN CANADA AND CARVE OUT OVER THE GREAT LAKES REGION AND NORTHEAST STATES THIS WEEKEND. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... VERY SLOW SEWD DRIFTING COLD FRONT NOW LOCATED FROM 20S KCLE ENE THROUGH KGKJ NEWD THROUGH WARREN AND KELZ THIS HOUR. TO THE SOUTH... SCATTERED SHOWERS ARE BEING MAINTAINED IN THE COUPLED JET REGION BETWEEN A 65-70KT 250 KT JET OVER SOUTHWEST PA AND A 90KT 250MB JET EXITING THE CENTRAL NEW ENGLAND COAST. RADAR OBSERVATIONS AND MODEL DIAGNOSTICS OF EPV INDICATE SOME CSI BANDING OVER THE WEST CENTRAL MOUNTAINS WHICH WILL BRING SOME LOCALLY HIGHER RAINFALL AMOUNTS IN THESE AREAS AND POINTS EASTWARD. POOL OF DEEPEST LAYER MOISTURE LIES ALONG THIS AXIS FROM SOUTHEAST OHIO EASTWARD ALONG AND NORTH OF THE PA TURNPIKE. ELONGATED 5H SHORTWAVE AXIS DROPPING SOUTHWARD TOWARDS THE MASON DIXON LINE IS MAINTAINING A LINE OF THUNDERSTORMS FROM THE IN/KY BORDER NORTHEASTWARD TO WESTERN AND NORTHERN WV...WHICH MAY GRAZE AREAS OF THE SOUTH CENTRAL MOUNTAINS AND LOWER SUSQ RIVER VALLEY ALONG THE MARYLAND BORDER OVERNIGHT. LATEST NAM AND RUC DEPICT THIS WELL...TARGETING SWRN AND SCENT COUNTIES OF THE CWA AFTER 06Z WITH THE EXPANDING AREA OF SHOWERS. THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING STATIONARY THERE THROUGH THURSDAY NIGHT. A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3 TENTHS ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS OF THE STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS POSSIBLY SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS THE NRN MTNS. SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER 50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/... FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH. THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S. MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED STATES WILL LIFT OUT THURSDAY NIGHT AND FRIDAY IN FAVOR OF A STRONGER UPPER TROF DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND CUTTING OFF OVER THE CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY AND SUNDAY. THIS WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE REGION ON THURSDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS RETURN FOR LATER SATURDAY AND SUNDAY OVER CENTRAL PA. THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE THIS WEEK AND THIS WEEKEND...ALSO...BOTH THE GFS AND EC SHIFT FOCUS OF HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE UPPER LOW IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT LAKES. WHILE UNSETTLED WILL PERSIST THROUGH THE WEEKEND AND INTO MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE EAST COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL APPEARS LOW. CURRENT MODEL SOLUTIONS SHOW A POSSIBLE RETURN TO DRIER CONDITIONS FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY ACROSS THE OHIO VALLEY AND INTO PA. WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... A FRONTAL BOUNDARY WILL MOVE SLOWLY SOUTH ACROSS THE CWA OVERNIGHT WITH WEAK MID-LEVEL WAVES CONTINUING TO MOVE W-E OVERHEAD. THIS WILL KEEP MENTION OF RAIN FOR MOST TAF SITES OVERNIGHT...WITH BEST LIKELIHOOD IN KJST-KAOO. CIGS ACROSS THE HIGHER TERRAIN ALREADY MVFR...AND THESE WILL LOWER TO IFR MAINLY AFTER 06Z AS STRATOCU DECK THICKENS AND SPREADS INTO CENTRAL MTNS AND LOWER SUSQ /LATE/. KBFD WILL SEE IFR CONDITIONS AROUND FROPA...THEN GRADUAL IMPROVEMENT AS 12Z APPROACHES AS DRIER AIR BEGINS TO SLIP IN FROM THE NW. THE FRONTAL BOUNDARY WILL MOST LIKELY STALL OUT NEAR THE PA/MD BORDER ON THU. SO THE THREAT OF SHOWERS WILL CONTINUE OVER THE SOUTHERN THIRD. CIGS WILL BEGIN AT IFR/MVFR BUT GRADUALLY RETURN TO VFR BY MID/LATE MORNING...WITH INTERMITTENT REDUCTIONS IN SHOWERS ACROSS THE SOUTH. OUTLOOK... FRI-SUN...VFR TO MVFR WITH SCT SHOWERS - MAINLY S AND E. MON...SHOWERS POSS NW...VFR ELSEWHERE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/LAMBERT NEAR TERM...DEVOIR/LAMBERT SHORT TERM...DANGELO LONG TERM...DEVOIR/GARTNER AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1237 AM EDT THU SEP 27 2012 .SYNOPSIS... A SLOW MOVING COLD FRONTAL BOUNDARY JUST SOUTHEAST OF THE LAKE ERIE SHORE WILL DRIFT SOUTH ACROSS THE STATE AND BECOME LOCATED NEAR THE PENNSYLVANIA...MARYLAND BORDER WHERE IT WILL STALL OUT RIGHT INTO FRIDAY. THE CLOSE PROXIMITY OF THIS FRONT WILL MAINTAIN THE THREAT OF OCCASIONAL RAIN OVER THE SOUTHERN THIRD OF THE KEYSTONE STATE FOR THURSDAY AND FRIDAY. A DEEP UPPER LEVEL TROUGH IS FORECAST TO DROP SOUTHWARD FROM EASTERN CANADA AND CARVE OUT OVER THE GREAT LAKES REGION AND NORTHEAST STATES THIS WEEKEND. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... VERY SLOW SEWD DRIFTING COLD FRONT NOW LOCATED FROM 20S KCLE ENE THROUGH KGKJ NEWD THROUGH KBFD AND KELZ THIS HOUR. TO THE SOUTH... SCATTERED SHOWERS ARE BEING MAINTAINED IN THE COUPLED JET REGION BETWEEN A 65-70KT 250 KT JET OVER SOUTHWEST PA AND A 90KT 250MB JET EXITING THE CENTRAL NEW ENGLAND COAST. RADAR OBSERVATIONS AND MODEL DIAGNOSTICS OF EPV INDICATE SOME CSI BANDING OVER THE WEST CENTRAL MOUNTAINS WHICH WILL BRING SOME LOCALLY HIGHER RAINFALL AMOUNTS IN THESE AREAS AND POINTS EASTWARD. POOL OF DEEPEST LAYER MOISTURE LIES ALONG THIS AXIS FROM SOUTHEAST OHIO EASTWARD ALONG AND NORTH OF THE PA TURNPIKE. ELONGATED 5H SHORTWAVE AXIS DROPPING SOUTHWARD TOWARDS THE MASON DIXON LINE IS MAINTAINING A LINE OF THUNDERSTORMS FROM THE IN/KY BORDER NORTHEASTWARD TO WESTERN AND NORTHERN WV...WHICH MAY GRAZE AREAS OF THE SOUTH CENTRAL MOUNTAINS AND LOWER SUSQ RIVER VALLEY ALONG THE MARYLAND BORDER OVERNIGHT. LATEST NAM AND RUC DEPICT THIS WELL...TARGETING SWRN AND SCENT COUNTIES OF THE CWA AFTER 06Z WITH THE EXPANDING AREA OF SHOWERS. THE COLD FRONT WILL BE SITUATED NEAR OR JUST TO THE NORTH OF INTERSTATE 80 BY 09Z THURSDAY...BEFORE DRIFTING TO NEAR /OR JUST SOUTH OF/ THE MASON DIXON LINE BY MIDDAY THURSDAY AND BECOMING STATIONARY THERE THROUGH THURSDAY NIGHT. A BLEND OF THE VARIOUS MODEL/ENSEMBLE GUIDANCE GIVES 1 TO 3 TENTHS ADDITIONAL RAINFALL ACROSS THE SOUTHERN HALF TO TWO THIRDS OF THE STATE...WITH A FEW SPOTS IN SOUTHERN PENN AND THE LAURELS POSSIBLY SEEING AROUND 0.50 INCH. LESS THAN 0.10 WILL OCCUR ACROSS THE NRN MTNS. SOME LATE NIGHT CLEARING SHOULD SNEAK INTO THE FAR NORTH IN THE WAKE OF THE CFRONT...ALLOWING TEMPS TO DIP INTO THE UPPER 40S TO LOWER 50S. THE CENTRAL AND SOUTHERN ZONES WILL STAY MAINLY OVC WITH MINS GENERALLY BETWEEN 55 AND 60F...AND T/TD SPREADS VERY TIGHT. && .SHORT TERM /8 AM THIS MORNING THROUGH 6 PM FRIDAY/... FRONT MOVES LITTLE IF AT ALL ON THURSDAY...AND GFS AND NAM STILL PLACE BEST CONVERGENCE OVER THE TURNPIKE OR JUST TO THE SOUTH. THUS...A PATH FOR SHOWERS WILL STILL LINGER. WILL KEEP POPS IN THE MID/LOW CHC RANGE FOR THE SRN THIRD OF THE AREA. ENOUGH DRY AIR MOVES IN FROM THE NORTH TO DRY UP THE NRN HALF OF THE AREA...AND IT SHOULD BECOME SUNNY IN THE NRN TIER AFTER A CLOUDY START UNDER LOW CLOUDS. MIXING COULD DROP DEWPOINTS IN N INTO THE LOWER 40S. MAXES WILL DEPEND ON HOW MUCH CLOUD COVER IS OVER THE SRN HALF OF THE AREA. WILL NUDGE THE GUID NUMS FOR THE SRN HALF DOWN A FEW DEGS...BUT KEEP CLOSE TO MOS AVG IN THE N. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... UPPER TROF OVER SOUTHEAST CANADA AND THE NORTHEASTERN UNITED STATES WILL LIFT OUT THURSDAY NIGHT AND FRIDAY IN FAVOR OF A STRONGER UPPER TROF DIGGING SHARPLY SOUTHWARD THROUGH ONTARIO AND CUTTING OFF OVER THE CENTRAL AND EASTERN GREAT LAKES LATE SATURDAY AND SUNDAY. THIS WILL BRING SHORT-LIVED IMPROVING CONDITIONS TO THE REGION ON THURSDAY NIGHT BEFORE INCREASINGLY UNSETTLED CONDITIONS RETURN FOR LATER SATURDAY AND SUNDAY OVER CENTRAL PA. THE GFS AND ECMWF ARE SIMILAR IN OVERALL SYNOPTIC EVOLUTION LATE THIS WEEK AND THIS WEEKEND...ALSO...BOTH THE GFS AND EC SHIFT FOCUS OF HEAVIER QPF OVER NORTH CENTRAL PA INTO NY STATE AS THE UPPER LOW IS FORECAST TO CUT OFF OVER THE CENTRAL AND EASTERN GREAT LAKES. WHILE UNSETTLED WILL PERSIST THROUGH THE WEEKEND AND INTO MONDAY WITH A FRONTAL BOUNDARY STALLED SOMEWHERE ALONG THE EAST COAST...THE THREAT OF WIDESPREAD SIGNIFICANT RAINFALL STILL APPEARS LOW. CURRENT MODEL SOLUTIONS SHOW A POSSIBLE RETURN TO DRIER CONDITIONS FROM TUESDAY ONWARD AS THE UPPER FLOW TURNS WESTERLY ACROSS THE OHIO VALLEY AND INTO PA. WITH CLOUDS AND SHOWERS ABUNDANT THROUGH MONDAY...MIN TEMPERATURES WILL GENERALLY BE A FEW DEGREES ABOVE NORMAL AND MAX TEMPS A FEW DEGREES BELOW. AS DRIER WEATHER MOVES IN TUES AND WED...A TURN TO AT LEAST SLIGHTLY ABOVE NORMAL TEMPERATURES SEEMS REASONABLE. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... A FRONTAL BOUNDARY WILL MOVE SLOWLY SOUTH ACROSS THE CWA OVERNIGHT WITH WEAK MID-LEVEL WAVES CONTINUING TO MOVE W-E OVERHEAD. THIS WILL KEEP MENTION OF RAIN FOR MOST TAF SITES OVERNIGHT...WITH BEST LIKELIHOOD IN KJST-KAOO. CIGS ACROSS THE HIGHER TERRAIN ALREADY MVFR...AND THESE WILL LOWER TO IFR MAINLY AFTER 06Z AS STRATOCU DECK THICKENS AND SPREADS INTO CENTRAL MTNS AND LOWER SUSQ /LATE/. KBFD WILL SEE IFR CONDITIONS AROUND FROPA...THEN GRADUAL IMPROVEMENT AS 12Z APPROACHES AS DRIER AIR BEGINS TO SLIP IN FROM THE NW. THE FRONTAL BOUNDARY WILL MOST LIKELY STALL OUT NEAR THE PA/MD BORDER ON THU. SO THE THREAT OF SHOWERS WILL CONTINUE OVER THE SOUTHERN THIRD. CIGS WILL BEGIN AT IFR/MVFR BUT GRADUALLY RETURN TO VFR BY MID/LATE MORNING...WITH INTERMITTENT REDUCTIONS IN SHOWERS ACROSS THE SOUTH. OUTLOOK... FRI-SUN...VFR TO MVFR WITH SCT SHOWERS - MAINLY S AND E. MON...SHOWERS POSS NW...VFR ELSEWHERE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/LAMBERT NEAR TERM...DEVOIR/LAMBERT SHORT TERM...DANGELO LONG TERM...DEVOIR/GARTNER AVIATION...RXR
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
1246 PM CDT THU SEP 27 2012 .UPDATE... UPDATED FOR AVIATION. && .PREV DISCUSSION... /ISSUED 622 AM CDT THU SEP 27 2012/ UPDATE...AVIATION DISCUSSION. PREV DISCUSSION... /ISSUED 231 AM CDT THU SEP 27 2012/ DISCUSSION... A STALLED FRONT REMAINS LOCATED ACROSS SOUTHERN MISSOURI THIS MORNING. SHOWERS AND THUNDERSTORMS ARE CURRENTLY DEVELOPING ALONG THE BOUNDARY. LATEST HRRR MODEL INDICATES THESE SHOWERS AND THUNDERSTORMS WILL BEGIN MOVING SOUTHEAST INTO THE CWA. LOOKING AT LATEST RADAR IMAGES...BEGINNING TO SEE INDIVIDUAL STORMS MOVING TO THE SOUTHEAST. AS A RESULT...WILL CONTINUE WITH LIKELY POPS ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND NORTHWEST TENNESSEE INTO THE MORNING HOURS. HRRR SHOWS ACTIVITY DYING OUT BY NOON TIME. DURING THE AFTERNOON...REDEVELOPMENT WILL LIKELY OCCUR ACROSS SOUTHERN MISSOURI NEAR THE FRONT. SOME OF THE ACTIVITY COULD SKIRT NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL AND EXTREME NORTHWEST TENNESSEE. WILL GO WITH 40 POPS IN THE AFTERNOON FOR THESE AREAS. ELSEWHERE...CONDITIONS SHOULD STAY DRY. ALTHOUGH...MAY SEE MOSTLY CLOUDY CONDITIONS MAINLY FROM BLOW OFF FROM CONVECTION OCCURRING TO THE NORTH OR WEST. HIGHS WILL BE IN THE 80S. TONIGHT...EXPECT WHATEVER ACTIVITY THAT DEVELOPS THIS AFTERNOON ACROSS SOUTHERN MISSOURI TO BEGIN SPREADING SOUTHWARD INTO THE CWA AS MODELS INDICATE FRONT MAY START MOVING TO THE SOUTH. BEST CHANCES WILL OCCUR ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND WEST TENNESSEE. LOWS WILL BE IN THE 60S. FRIDAY AND FRIDAY NIGHT...FRONT PUSHES INTO THE CWA THUS EXPECT CHANCES FOR SHOWERS AND THUNDERSTORMS TO SPREAD ACROSS THE ENTIRE CWA. HOWEVER...EXPECT RAINFALL AMOUNTS TO REMAIN ON THE LIGHT SIDE. THE WEEKEND...BY SATURDAY MORNING...COOLER AND DRIER AIR WILL BEGIN SPREADING INTO PORTIONS OF NORTHWEST TENNESSEE. EXPECT FRONT TO LIKELY BE LOCATED JUST TO THE SOUTH OF THE CWA. HOWEVER STILL EXPECT SOME POST FRONTAL RAIN TO OCCUR MAINLY OVER NORTH MISSISSIPPI AND EAST CENTRAL ARKANSAS. BY SATURDAY NIGHT INTO SUNDAY...EXPECT COOLER AND DRIER AIR TO HAVE FILTERED INTO MUCH OF THE CWA WITH ONLY EXTREME SOUTHERN PORTIONS OF THE CWA SEEING CONTINUING CHANCES FOR RAIN. MONDAY THROUGH WEDNESDAY...A BROAD UPPER TROF WILL REMAIN OVER THE MIDSOUTH. MODELS KEEP FLIPPING BACK AND FORTH ON WHETHER A CLOSED UPPER LOW FORMS. A SFC LOW IS EXPECTED TO DEVELOP ALONG THE GULF COAST. DEPENDING ON THE LOCATION OF THE LOW...SOME RAIN COULD SPREAD NORTHWARD INTO NORTHEAST MISSISSIPPI AS IT PUSHES EAST. FOR NOW WILL CONTINUE WITH DRY FORECAST UNTIL MODELS SHOW SOME CONSISTENCY. KRM && .AVIATION... 18Z TAFS A SURFACE COLD FRONT OVER SOUTHERN IL TO JUST SOUTH OF STL AT MIDDAY WILL SETTLE INTO THE MIDSOUTH TOWARD LATE AFTERNOON. NAM AND HRRR MODELS ARE CONSISTENT IN DEVELOPING SCATTERED SHRA/TSRA ALONG AND BEHIND THE FRONT. SLIGHT TO MODERATE LOW LEVEL INSTABILITY WILL BE SUPPORTIVE OF TSRA THROUGH 00Z...BUT FRONTAL PUSH WILL BE WEAK. WITH LOWER SUN ANGLES DURING THE LATE AFTERNOON...TSRA COVERAGE SHOULD BE LIMITED. HAVE INCLUDED A BRIEF VCTS AT MEM AT 22Z. CONFIDENCE IS NOT SUFFICIENT TO WARRANT A TEMPO FOR THE SCHEDULED 18Z TAFS. VFR AND LIGHT /LESS THAN 5KT/ SURFACE WINDS LATE THIS EVENING AND EARLY OVERNIGHT AT MEM. PWB && .PRELIMINARY POINT TEMPS/POPS... MEM 84 69 83 65 / 20 30 50 30 MKL 83 63 81 59 / 30 40 60 20 JBR 82 64 79 59 / 60 60 60 40 TUP 86 66 86 63 / 10 10 40 30 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1241 PM CDT THU SEP 27 2012 .UPDATE...FOR 18Z AVIATION FORECAST && .AVIATION... AIR MASS ACROSS THE TENNESSEE VALLEY IS FAIRLY DEEP IN MOISTURE TO ABOUT 25K FEET THROUGH 12Z SATURDAY. EVEN THOUGH FRONTAL BOUNDARY IS LAYING JUST TO OUR NORTH SEEMS LIKE SHOWERS THAT MOVED IN FROM THE WEST EARLIER THIS MORNING WERE TIED MORE TO ONE OF THE WEAK MID LEVEL DISTURBANCES THAT HAS BEEN TRANSIENT IN THE WEST TO EAST FLOW ALOFT FROM OKLAHOMA TO TENNESSEE. BASICALLY LOOKING FOR VFR CONDITIONS THROUGH ABOUT 08Z TONIGHT THEN GOING DOWNHILL RATHER QUICKLY DUE TO LOW CEILINGS AND FOG. SHOULD RETURN TO VFR BY 15Z. BOYD && .PREV DISCUSSION... /ISSUED 946 AM CDT THU SEP 27 2012/ UPDATE... RADAR IMAGERY THIS MORNING SHOWS AN AREA OF SHOWERS AND THUNDERSTORMS EXTENDING FROM WESTERN KY TO JUST NORTH OF MEM MOVING EASTWARD. LATEST HRRR RUNS SEEM TO HAVE A DECENT HANDLE ON THIS ACTIVITY AND BRING IT ACROSS NORTHERN ZONES THROUGH THE REST OF THE MORNING INTO THE AFTERNOON HOURS. ADDITIONAL BUT MORE ISOLATED TO WIDELY SCATTERED SHOWERS AND MAYBE A STORM OR TWO ALSO WILL LIKELY FORM TO THE SOUTH OF THIS ONGOING ACTIVITY AS WELL. BASED ON THIS REASONING...HAVE KEPT THE INHERITED POPS GENERALLY IN PLACE WITH SOME ADJUSTMENTS...SHOWING CATEGORICAL POPS OVER THE NORTHWEST ZONES DIMINISHING TO SLIGHT/NO CHANCE ALONG THE ALABAMA BORDER. CLOUD COVER ALSO ADJUSTED GENERALLY UPWARD WHILE HIGH TEMPS WERE NUDGED DOWN OVER THE NORTHERN HALF. REST OF FORECAST WAS LEFT UNCHANGED AT THIS TIME. PREV DISCUSSION... /ISSUED 708 AM CDT THU SEP 27 2012/ AVIATION 12Z DISCUSSION... COLD FRONT TO THE NORTH OF TN THIS MORNING WILL MOVE SOUTHWARD AND WILL BE LOCATED IN CLOSE PROXIMITY OF THE TAF AREAS ON FRIDAY MORNING. ELEVATED INSTABILITY LEVELS WILL ALLOW FOR SOME ISOL TSTM DEVELOPMENT THIS AFTERNOON. THEN AS THE FRONT SINKS SOUTHWARD...ISOL TO SCT SHOWER ACTIVITY WILL CONTINUE OVERNIGHT. IFR CONDITIONS WILL OCCUR BETWEEN 06Z AND 12Z AS CIGS AND VSBYS LOWER. PREV DISCUSSION... /ISSUED 426 AM CDT THU SEP 27 2012/ DISCUSSION... CURRENTLY...THE MAIN MOISTURE AXIS REMAINS DRAPED ACROSS NORTHERN ARKANSAS AND KENTUCKY WITH SHOWERS AND THUNDERSTORMS MOVING EAST ACROSS SOUTHERN MISSOURI AND WESTERN KY. CURRENT RADAR TRENDS AND HRRR SUGGEST THIS ACTIVITY WILL CONTINUE INTO NORTHWESTERN MIDDLE TN WITH A FEW STRAY SHOWERS AFFECTING COUNTIES MAINLY NORTH OF THE I-40 CORRIDOR THROUGH NOON. ACTIVITY WILL LIKELY WEAKEN AS IT MOVES EAST THROUGH MIDDLE TN. HOWEVER HRRR INDICATES SCATTERED ACTIVITY MAY PICK UP AGAIN THURSDAY AFTERNOON AND EVENING AS THE COLD FRONT BEGINS TO MOVE SOUTH. THE BEST CHANCE FOR PRECIP WILL BE OVERNIGHT THURSDAY NIGHT AND INTO FRIDAY. SOME STORMS ON FRIDAY COULD BECOME STRONG...SOUNDINGS INDICATE STEEP LOW LEVEL LAPSE RATES AND BASICALLY NO CONVECTIVE INHIBITION. THIS WEEKEND...COOLER AND DRIER AIR WILL FOLLOW BEHIND THE FRONT AND SINK SOUTH SATURDAY AFTERNOON AND SUNDAY. MOSTLY TO PARTLY CLOUDY SKIES COULD PERSIST THROUGH SUNDAY...HIGH TEMPERATURES COOLING DOWN INTO THE 70S THIS WEEKEND AFTER THE FRONT PASSES WITH LOWS IN THE 50S. MONDAY THRU WEDNESDAY...SURFACE HIGH PRESSURE OVER THE OHIO VALLEY WILL INFLUENCE COOLER TEMPS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES ON MONDAY AND TUESDAY. CURRENT MODELS SUGGEST THE FRONT THAT CAME THROUGH THE AREA SATURDAY IS TO REMAIN SOUTHEAST OF TENNESSEE MONDAY AND TUESDAY. AN UPPER LOW OVER THE SOUTHERN MISSISSIPPI VALLEY TOWARD THE END OF THE FORECAST PERIOD WILL BRING ANOTHER CHANCE OF RAIN WEDNESDAY. TEMPS IN THE LONG TERM ARE EXPECTED TO BE AROUND NORMAL. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
946 AM CDT THU SEP 27 2012 .UPDATE... RADAR IMAGERY THIS MORNING SHOWS AN AREA OF SHOWERS AND THUNDERSTORMS EXTENDING FROM WESTERN KY TO JUST NORTH OF MEM MOVING EASTWARD. LATEST HRRR RUNS SEEM TO HAVE A DECENT HANDLE ON THIS ACTIVITY AND BRING IT ACROSS NORTHERN ZONES THROUGH THE REST OF THE MORNING INTO THE AFTERNOON HOURS. ADDITIONAL BUT MORE ISOLATED TO WIDELY SCATTERED SHOWERS AND MAYBE A STORM OR TWO ALSO WILL LIKELY FORM TO THE SOUTH OF THIS ONGOING ACTIVITY AS WELL. BASED ON THIS REASONING...HAVE KEPT THE INHERITED POPS GENERALLY IN PLACE WITH SOME ADJUSTMENTS...SHOWING CATEGORICAL POPS OVER THE NORTHWEST ZONES DIMINISHING TO SLIGHT/NO CHANCE ALONG THE ALABAMA BORDER. CLOUD COVER ALSO ADJUSTED GENERALLY UPWARD WHILE HIGH TEMPS WERE NUDGED DOWN OVER THE NORTHERN HALF. REST OF FORECAST WAS LEFT UNCHANGED AT THIS TIME. && .PREV DISCUSSION... /ISSUED 708 AM CDT THU SEP 27 2012/ AVIATION 12Z DISCUSSION... COLD FRONT TO THE NORTH OF TN THIS MORNING WILL MOVE SOUTHWARD AND WILL BE LOCATED IN CLOSE PROXIMITY OF THE TAF AREAS ON FRIDAY MORNING. ELEVATED INSTABILITY LEVELS WILL ALLOW FOR SOME ISOL TSTM DEVELOPMENT THIS AFTERNOON. THEN AS THE FRONT SINKS SOUTHWARD...ISOL TO SCT SHOWER ACTIVITY WILL CONTINUE OVERNIGHT. IFR CONDITIONS WILL OCCUR BETWEEN 06Z AND 12Z AS CIGS AND VSBYS LOWER. PREV DISCUSSION... /ISSUED 426 AM CDT THU SEP 27 2012/ DISCUSSION... CURRENTLY...THE MAIN MOISTURE AXIS REMAINS DRAPED ACROSS NORTHERN ARKANSAS AND KENTUCKY WITH SHOWERS AND THUNDERSTORMS MOVING EAST ACROSS SOUTHERN MISSOURI AND WESTERN KY. CURRENT RADAR TRENDS AND HRRR SUGGEST THIS ACTIVITY WILL CONTINUE INTO NORTHWESTERN MIDDLE TN WITH A FEW STRAY SHOWERS AFFECTING COUNTIES MAINLY NORTH OF THE I-40 CORRIDOR THROUGH NOON. ACTIVITY WILL LIKELY WEAKEN AS IT MOVES EAST THROUGH MIDDLE TN. HOWEVER HRRR INDICATES SCATTERED ACTIVITY MAY PICK UP AGAIN THURSDAY AFTERNOON AND EVENING AS THE COLD FRONT BEGINS TO MOVE SOUTH. THE BEST CHANCE FOR PRECIP WILL BE OVERNIGHT THURSDAY NIGHT AND INTO FRIDAY. SOME STORMS ON FRIDAY COULD BECOME STRONG...SOUNDINGS INDICATE STEEP LOW LEVEL LAPSE RATES AND BASICALLY NO CONVECTIVE INHIBITION. THIS WEEKEND...COOLER AND DRIER AIR WILL FOLLOW BEHIND THE FRONT AND SINK SOUTH SATURDAY AFTERNOON AND SUNDAY. MOSTLY TO PARTLY CLOUDY SKIES COULD PERSIST THROUGH SUNDAY...HIGH TEMPERATURES COOLING DOWN INTO THE 70S THIS WEEKEND AFTER THE FRONT PASSES WITH LOWS IN THE 50S. MONDAY THRU WEDNESDAY...SURFACE HIGH PRESSURE OVER THE OHIO VALLEY WILL INFLUENCE COOLER TEMPS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES ON MONDAY AND TUESDAY. CURRENT MODELS SUGGEST THE FRONT THAT CAME THROUGH THE AREA SATURDAY IS TO REMAIN SOUTHEAST OF TENNESSEE MONDAY AND TUESDAY. AN UPPER LOW OVER THE SOUTHERN MISSISSIPPI VALLEY TOWARD THE END OF THE FORECAST PERIOD WILL BRING ANOTHER CHANCE OF RAIN WEDNESDAY. TEMPS IN THE LONG TERM ARE EXPECTED TO BE AROUND NORMAL. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHAMBURGER
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
708 AM CDT THU SEP 27 2012 .AVIATION 12Z DISCUSSION... COLD FRONT TO THE NORTH OF TN THIS MORNING WILL MOVE SOUTHWARD AND WILL BE LOCATED IN CLOSE PROXIMITY OF THE TAF AREAS ON FRIDAY MORNING. ELEVATED INSTABILITY LEVELS WILL ALLOW FOR SOME ISOL TSTM DEVELOPMENT THIS AFTERNOON. THEN AS THE FRONT SINKS SOUTHWARD...ISOL TO SCT SHOWER ACTIVITY WILL CONTINUE OVERNIGHT. IFR CONDITIONS WILL OCCUR BETWEEN 06Z AND 12Z AS CIGS AND VSBYS LOWER. && .PREV DISCUSSION... /ISSUED 426 AM CDT THU SEP 27 2012/ DISCUSSION... CURRENTLY...THE MAIN MOISTURE AXIS REMAINS DRAPED ACROSS NORTHERN ARKANSAS AND KENTUCKY WITH SHOWERS AND THUNDERSTORMS MOVING EAST ACROSS SOUTHERN MISSOURI AND WESTERN KY. CURRENT RADAR TRENDS AND HRRR SUGGEST THIS ACTIVITY WILL CONTINUE INTO NORTHWESTERN MIDDLE TN WITH A FEW STRAY SHOWERS AFFECTING COUNTIES MAINLY NORTH OF THE I-40 CORRIDOR THROUGH NOON. ACTIVITY WILL LIKELY WEAKEN AS IT MOVES EAST THROUGH MIDDLE TN. HOWEVER HRRR INDICATES SCATTERED ACTIVITY MAY PICK UP AGAIN THURSDAY AFTERNOON AND EVENING AS THE COLD FRONT BEGINS TO MOVE SOUTH. THE BEST CHANCE FOR PRECIP WILL BE OVERNIGHT THURSDAY NIGHT AND INTO FRIDAY. SOME STORMS ON FRIDAY COULD BECOME STRONG...SOUNDINGS INDICATE STEEP LOW LEVEL LAPSE RATES AND BASICALLY NO CONVECTIVE INHIBITION. THIS WEEKEND...COOLER AND DRIER AIR WILL FOLLOW BEHIND THE FRONT AND SINK SOUTH SATURDAY AFTERNOON AND SUNDAY. MOSTLY TO PARTLY CLOUDY SKIES COULD PERSIST THROUGH SUNDAY...HIGH TEMPERATURES COOLING DOWN INTO THE 70S THIS WEEKEND AFTER THE FRONT PASSES WITH LOWS IN THE 50S. MONDAY THRU WEDNESDAY...SURFACE HIGH PRESSURE OVER THE OHIO VALLEY WILL INFLUENCE COOLER TEMPS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES ON MONDAY AND TUESDAY. CURRENT MODELS SUGGEST THE FRONT THAT CAME THROUGH THE AREA SATURDAY IS TO REMAIN SOUTHEAST OF TENNESSEE MONDAY AND TUESDAY. AN UPPER LOW OVER THE SOUTHERN MISSISSIPPI VALLEY TOWARD THE END OF THE FORECAST PERIOD WILL BRING ANOTHER CHANCE OF RAIN WEDNESDAY. TEMPS IN THE LONG TERM ARE EXPECTED TO BE AROUND NORMAL. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 21
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
622 AM CDT THU SEP 27 2012 .UPDATE...AVIATION DISCUSSION. && .PREV DISCUSSION... /ISSUED 231 AM CDT THU SEP 27 2012/ DISCUSSION... A STALLED FRONT REMAINS LOCATED ACROSS SOUTHERN MISSOURI THIS MORNING. SHOWERS AND THUNDERSTORMS ARE CURRENTLY DEVELOPING ALONG THE BOUNDARY. LATEST HRRR MODEL INDICATES THESE SHOWERS AND THUNDERSTORMS WILL BEGIN MOVING SOUTHEAST INTO THE CWA. LOOKING AT LATEST RADAR IMAGES...BEGINNING TO SEE INDIVIDUAL STORMS MOVING TO THE SOUTHEAST. AS A RESULT...WILL CONTINUE WITH LIKELY POPS ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND NORTHWEST TENNESSEE INTO THE MORNING HOURS. HRRR SHOWS ACTIVITY DYING OUT BY NOON TIME. DURING THE AFTERNOON...REDEVELOPMENT WILL LIKELY OCCUR ACROSS SOUTHERN MISSOURI NEAR THE FRONT. SOME OF THE ACTIVITY COULD SKIRT NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL AND EXTREME NORTHWEST TENNESSEE. WILL GO WITH 40 POPS IN THE AFTERNOON FOR THESE AREAS. ELSEWHERE...CONDITIONS SHOULD STAY DRY. ALTHOUGH...MAY SEE MOSTLY CLOUDY CONDITIONS MAINLY FROM BLOW OFF FROM CONVECTION OCCURRING TO THE NORTH OR WEST. HIGHS WILL BE IN THE 80S. TONIGHT...EXPECT WHATEVER ACTIVITY THAT DEVELOPS THIS AFTERNOON ACROSS SOUTHERN MISSOURI TO BEGIN SPREADING SOUTHWARD INTO THE CWA AS MODELS INDICATE FRONT MAY START MOVING TO THE SOUTH. BEST CHANCES WILL OCCUR ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND WEST TENNESSEE. LOWS WILL BE IN THE 60S. FRIDAY AND FRIDAY NIGHT...FRONT PUSHES INTO THE CWA THUS EXPECT CHANCES FOR SHOWERS AND THUNDERSTORMS TO SPREAD ACROSS THE ENTIRE CWA. HOWEVER...EXPECT RAINFALL AMOUNTS TO REMAIN ON THE LIGHT SIDE. THE WEEKEND...BY SATURDAY MORNING...COOLER AND DRIER AIR WILL BEGIN SPREADING INTO PORTIONS OF NORTHWEST TENNESSEE. EXPECT FRONT TO LIKELY BE LOCATED JUST TO THE SOUTH OF THE CWA. HOWEVER STILL EXPECT SOME POST FRONTAL RAIN TO OCCUR MAINLY OVER NORTH MISSISSIPPI AND EAST CENTRAL ARKANSAS. BY SATURDAY NIGHT INTO SUNDAY...EXPECT COOLER AND DRIER AIR TO HAVE FILTERED INTO MUCH OF THE CWA WITH ONLY EXTREME SOUTHERN PORTIONS OF THE CWA SEEING CONTINUING CHANCES FOR RAIN. MONDAY THROUGH WEDNESDAY...A BROAD UPPER TROF WILL REMAIN OVER THE MIDSOUTH. MODELS KEEP FLIPPING BACK AND FORTH ON WHETHER A CLOSED UPPER LOW FORMS. A SFC LOW IS EXPECTED TO DEVELOP ALONG THE GULF COAST. DEPENDING ON THE LOCATION OF THE LOW...SOME RAIN COULD SPREAD NORTHWARD INTO NORTHEAST MISSISSIPPI AS IT PUSHES EAST. FOR NOW WILL CONTINUE WITH DRY FORECAST UNTIL MODELS SHOW SOME CONSISTENCY. KRM .AVIATION... 12Z TAFS A VERY SLOW MOVING COLD FRONT WILL SINK SOUTH ACROSS THE MIDSOUTH TODAY. WINDS WILL TURN NORTHERLY BEHIND THE FRONT REMAINING LESS THAN 10 KNOTS THROUGHOUT THE TAF CYCLE. A FEW SHOWERS WILL BE POSSIBLE...MAINLY BEFORE NOON TODAY AT JBR AND MKL...AND THEN AGAIN AT JBR...MKL AND MEM OVERNIGHT. PRECIPITATION IS NOT EXPECTED TO BE HEAVY ENOUGH TO REDUCE VISIBILITY SIGNIFICANTLY....VFR CONDITIONS WILL PREVAIL. && .PRELIMINARY POINT TEMPS/POPS... MEM 85 69 83 65 / 20 30 50 30 MKL 84 63 81 59 / 30 40 60 20 JBR 83 64 79 59 / 60 60 60 40 TUP 87 66 86 63 / 10 10 40 30 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
426 AM CDT THU SEP 27 2012 .DISCUSSION... CURRENTLY...THE MAIN MOISTURE AXIS REMAINS DRAPED ACROSS NORTHERN ARKANSAS AND KENTUCKY WITH SHOWERS AND THUNDERSTORMS MOVING EAST ACROSS SOUTHERN MISSOURI AND WESTERN KY. CURRENT RADAR TRENDS AND HRRR SUGGEST THIS ACTIVITY WILL CONTINUE INTO NORTHWESTERN MIDDLE TN WITH A FEW STRAY SHOWERS AFFECTING COUNTIES MAINLY NORTH OF THE I-40 CORRIDOR THROUGH NOON. ACTIVITY WILL LIKELY WEAKEN AS IT MOVES EAST THROUGH MIDDLE TN. HOWEVER HRRR INDICATES SCATTERED ACTIVITY MAY PICK UP AGAIN THURSDAY AFTERNOON AND EVENING AS THE COLD FRONT BEGINS TO MOVE SOUTH. THE BEST CHANCE FOR PRECIP WILL BE OVERNIGHT THURSDAY NIGHT AND INTO FRIDAY. SOME STORMS ON FRIDAY COULD BECOME STRONG...SOUNDINGS INDICATE STEEP LOW LEVEL LAPSE RATES AND BASICALLY NO CONVECTIVE INHIBITION. THIS WEEKEND...COOLER AND DRIER AIR WILL FOLLOW BEHIND THE FRONT AND SINK SOUTH SATURDAY AFTERNOON AND SUNDAY. MOSTLY TO PARTLY CLOUDY SKIES COULD PERSIST THROUGH SUNDAY...HIGH TEMPERATURES COOLING DOWN INTO THE 70S THIS WEEKEND AFTER THE FRONT PASSES WITH LOWS IN THE 50S. MONDAY THRU WEDNESDAY...SURFACE HIGH PRESSURE OVER THE OHIO VALLEY WILL INFLUENCE COOLER TEMPS AND PARTLY CLOUDY TO MOSTLY CLEAR SKIES ON MONDAY AND TUESDAY. CURRENT MODELS SUGGEST THE FRONT THAT CAME THROUGH THE AREA SATURDAY IS TO REMAIN SOUTHEAST OF TENNESSEE MONDAY AND TUESDAY. AN UPPER LOW OVER THE SOUTHERN MISSISSIPPI VALLEY TOWARD THE END OF THE FORECAST PERIOD WILL BRING ANOTHER CHANCE OF RAIN WEDNESDAY. TEMPS IN THE LONG TERM ARE EXPECTED TO BE AROUND NORMAL. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 83 64 79 61 / 20 60 60 20 CLARKSVILLE 82 60 77 59 / 90 70 50 20 CROSSVILLE 79 60 75 57 / 20 60 60 20 COLUMBIA 85 63 81 62 / 20 30 60 30 LAWRENCEBURG 85 60 82 62 / 10 20 60 30 WAVERLY 83 61 79 59 / 60 60 60 20 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 11
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
231 AM CDT THU SEP 27 2012 .DISCUSSION... A STALLED FRONT REMAINS LOCATED ACROSS SOUTHERN MISSOURI THIS MORNING. SHOWERS AND THUNDERSTORMS ARE CURRENTLY DEVELOPING ALONG THE BOUNDARY. LATEST HRRR MODEL INDICATES THESE SHOWERS AND THUNDERSTORMS WILL BEGIN MOVING SOUTHEAST INTO THE CWA. LOOKING AT LATEST RADAR IMAGES...BEGINNING TO SEE INDIVIDUAL STORMS MOVING TO THE SOUTHEAST. AS A RESULT...WILL CONTINUE WITH LIKELY POPS ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND NORTHWEST TENNESSEE INTO THE MORNING HOURS. HRRR SHOWS ACTIVITY DYING OUT BY NOON TIME. DURING THE AFTERNOON...REDEVELOPMENT WILL LIKELY OCCUR ACROSS SOUTHERN MISSOURI NEAR THE FRONT. SOME OF THE ACTIVITY COULD SKIRT NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL AND EXTREME NORTHWEST TENNESSEE. WILL GO WITH 40 POPS IN THE AFTERNOON FOR THESE AREAS. ELSEWHERE...CONDITIONS SHOULD STAY DRY. ALTHOUGH...MAY SEE MOSTLY CLOUDY CONDITIONS MAINLY FROM BLOW OFF FROM CONVECTION OCCURRING TO THE NORTH OR WEST. HIGHS WILL BE IN THE 80S. TONIGHT...EXPECT WHATEVER ACTIVITY THAT DEVELOPS THIS AFTERNOON ACROSS SOUTHERN MISSOURI TO BEGIN SPREADING SOUTHWARD INTO THE CWA AS MODELS INDICATE FRONT MAY START MOVING TO THE SOUTH. BEST CHANCES WILL OCCUR ACROSS NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL...AND WEST TENNESSEE. LOWS WILL BE IN THE 60S. FRIDAY AND FRIDAY NIGHT...FRONT PUSHES INTO THE CWA THUS EXPECT CHANCES FOR SHOWERS AND THUNDERSTORMS TO SPREAD ACROSS THE ENTIRE CWA. HOWEVER...EXPECT RAINFALL AMOUNTS TO REMAIN ON THE LIGHT SIDE. THE WEEKEND...BY SATURDAY MORNING...COOLER AND DRIER AIR WILL BEGIN SPREADING INTO PORTIONS OF NORTHWEST TENNESSEE. EXPECT FRONT TO LIKELY BE LOCATED JUST TO THE SOUTH OF THE CWA. HOWEVER STILL EXPECT SOME POST FRONTAL RAIN TO OCCUR MAINLY OVER NORTH MISSISSIPPI AND EAST CENTRAL ARKANSAS. BY SATURDAY NIGHT INTO SUNDAY...EXPECT COOLER AND DRIER AIR TO HAVE FILTERED INTO MUCH OF THE CWA WITH ONLY EXTREME SOUTHERN PORTIONS OF THE CWA SEEING CONTINUING CHANCES FOR RAIN. MONDAY THROUGH WEDNESDAY...A BROAD UPPER TROF WILL REMAIN OVER THE MIDSOUTH. MODELS KEEP FLIPPING BACK AND FORTH ON WHETHER A CLOSED UPPER LOW FORMS. A SFC LOW IS EXPECTED TO DEVELOP ALONG THE GULF COAST. DEPENDING ON THE LOCATION OF THE LOW...SOME RAIN COULD SPREAD NORTHWARD INTO NORTHEAST MISSISSIPPI AS IT PUSHES EAST. FOR NOW WILL CONTINUE WITH DRY FORECAST UNTIL MODELS SHOW SOME CONSISTENCY. KRM && .AVIATION... 06Z TAFS LIGHT WINDS AND VFR CONDITIONS ARE EXPECTED THROUGHOUT THE ENTIRE FORECAST AREA THROUGH THE PERIOD. FRONTAL BOUNDARY LOOKS TO START TO SLIDE SLOWLY ACROSS THE FORECAST AREA...ALLOWING FOR SOME THUNDERSTORMS TOMORROW ACROSS THE REGION BUT HAVE NOT ADDED CB OR TEMPO GROUPS AS OF YET WITH THE COVERAGE BEING ISOLATED TO SCTD ACROSS THE AREA MOST LIKELY AND EXACT INITIATION TIME OF STORMS NOT CLEAR. --ABS && .PRELIMINARY POINT TEMPS/POPS... MEM 85 69 83 65 / 20 30 50 30 MKL 84 63 81 59 / 30 40 60 20 JBR 83 64 79 59 / 60 60 60 40 TUP 87 66 86 63 / 10 10 40 30 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1204 AM CDT THU SEP 27 2012 .UPDATE... MAIN REASON FOR UPDATE WAS THE CANCEL THE REMAINDER OF SEVERE THUNDERSTORM WATCH 653 FROM THE REMAINDER OF THE TEXAS AND OKLAHOMA PANHANDLES. REMAINDER OF THE FORECAST LOOKS TO BE ON TRACK WITH NO OTHER UPDATES NEEDED. && .AVIATION... /06Z TAFS/ MAIN CONCERN FOR THIS FORECAST PERIOD CENTERS ON FOG/LOW CLOUDS AT KDHT/KGUY AND WHEN SHOWERS AND THUNDERSTORMS WILL AFFECT THE TERMINALS. ONGOING CONVECTION ACROSS THE EASTERN OKLAHOMA PANHANDLE AND THE NORTHEAST TEXAS PANHANDLE CONTINUES TO PUSH OFF TO THE EAST INTO WESTERN OKLAHOMA. CONVECTIVE TRENDS SHOW STORMS CONTINUING TO WEAKEN AS INSTABILITY CONTINUES TO WEAKEN ACROSS THE AREA. LATEST TTU WRF AND HRRR STILL SUGGEST AREA OF SHOWERS AND THUNDERSTORMS CURRENTLY IN EASTERN NEW MEXICO WILL MOVE INTO THE SOUTHERN TEXAS PANHANDLE OVERNIGHT. HOWEVER HAVE NOT INCLUDED TSRA MENTION IN THE KAMA TERMINAL DUE TO LOW CONFIDENCE IN THESE STORMS HOLDING TOGETHER AS THEY MOVE TOWARD KAMA. A FRONTAL BOUNDARY WAS SLIDING SOUTH INTO THE NORTHERN TEXAS PANHANDLE TONIGHT WHERE ITS EXPECTED TO STALL OVERNIGHT. LOW LEVEL MOISTURE WITH LIGHT UPSLOPE WINDS BEHIND THE FRONT MAY LEAD TO THE DEVELOPMENT OF LOW CLOUDS AND FOG AT KGUY/KDHT...WITH MVFR VISBYS AND CIGS. HAVE KEPT VFR CONDITIONS IN AT KAMA ALTHOUGH THERE IS A POSSIBILITY FOR LOW CLOUDS TO DEVELOP THURSDAY MORNING. THUNDERSTORMS MAY AFFECT ALL THREE TERMINALS THURSDAY HOWEVER TIMING AND LOCATION OF ANY STORMS IS UNCERTAIN SO HAVE OPTED TO KEPT OUT MENTION IN THE FORECAST. CLK && .PREV DISCUSSION... /ISSUED 1002 PM CDT WED SEP 26 2012/ UPDATE... HAVE REMOVED SEVERE THUNDERSTORM WATCH FROM CIMARRON...DALLAM... HARTLEY...AND SHERMAN COUNTIES FROM SEVERE THUNDERSTORM WATCH 653 AS THE ATMOSPHERE HAS STABILIZED WITH TEMPS COOLING DOWN INTO THE MID TO UPPER 50S. COMPLEX OF STRONG TO SEVERE THUNDERSTORMS CONTINUES TO MOVE ACROSS THE CENTRAL AND EASTERN OKLAHOMA PANHANDLE AND AN OUTFLOW BOUNDARY WAS RACING SOUTHWARD FROM THESE STORMS. HAVE OPTED TO LEAVE THE WATCH IN EFFECT FOR THE REMAINDER OF THE PANHANDLES UNTIL 11 PM AS THIS OUTFLOW BOUNDARY MAY PROVIDE A FOCUS FOR STORMS. HAVE ALSO ADJUSTED LOW TEMPS DOWN A FEW DEGREES IN THE NORTHWEST ZONES. UPDATED TEXT PRODUCTS HAVE BEEN SENT. CLK PREV DISCUSSION... /ISSUED 718 PM CDT WED SEP 26 2012/ AVIATION... /00Z TAFS/ COMPLEX AVIATION FORECAST SHAPING UP OVER THE NEXT 24 HOURS. ONGOING CONVECTION IS CURRENTLY NORTH AND WEST OF KGUY/KDHT AND WELL EAST OF THE KAMA TERMINAL. CURRENT RADAR REFLECTIVITY IMAGERY SHOWS ADDITIONAL DEVELOPMENT IN EASTERN NEW MEXICO WHICH THE 18Z TTU WRF AND 21Z HRRR ARE DEPICTING THIS INCREASING IN COVERAGE AS IT MOVES ACROSS THE PANHANDLES LATER TONIGHT. HAVE KEPT IN PREVIOUS MENTION OF -SHRA AS COOLING BOUNDARY LAYER TEMPS SHOULD LIMIT THE INSTABILITY AND THUS LOWER THE CHANCES FOR THUNDER DEVELOPMENT. LOW CLOUDS AND FOG ARE POSSIBLE AT KGUY/KDHT THURSDAY MORNING WHERE A LITTLE BETTER LOW LEVEL MOISTURE WILL RESIDE. HOWEVER HAVE KEPT CONDITIONS AT MVFR AS CONFIDENCE IS NOT TOO HIGH THAT WORSENING CONDITIONS WILL DEVELOP. HAVE KEPT A VFR FORECAST IN AT KAMA BUT MAY HAVE TO AMEND IF TRENDS SUGGEST CIGS AND/OR VISBYS LOWERING BELOW MVFR. STORMS CAN DEVELOP AT THE TERMINALS THURSDAY BUT HAVE OPTED TO LEAVE MENTION OUT OF THE TAFS DUE TO LOW CONFIDENCE ON TIMING AND WHERE STORMS WILL DEVELOP. CLK PREV DISCUSSION... /ISSUED 351 PM CDT WED SEP 26 2012/ DISCUSSION... THROUGH TONIGHT: A RATHER COMPLICATED AND SOMEWHAT LOW CONFIDENCE FORECAST HAS EVOLVED TODAY. A WEAK SURFACE TROUGH CURRENTLY STRETCHES FROM THE SOUTHERN TEXAS PANHANDLE TO NEAR THE RED RIVER. IN THE UPPER-LEVELS A CLOSED LOW CONTINUES TO SPIN OVER THE WESTERN COLORADO WITH A SUBTLE SHORTWAVE TROUGH...EJECTING OUT OF THIS LOW...NOW APPROACHING EASTERN NEW MEXICO. LARGE SCALE FORCING FOR ASCENT WILL BE ON THE INCREASE THROUGH THIS EVENING...AND WE EXPECT ISOLATED TO WIDELY SCATTERED CONVECTION TO INITIATE SOUTH AND WEST OF A BOISE CITY TO SHAMROCK LINE THROUGH 7 PM. A LOOSELY ORGANIZED COMPLEX OF STORMS MAY EVOLVE AFTER 11 PM ALONG AND EAST OF A GUYMON TO CLARENDON LINE AND STEADILY MARCH EASTWARD OVERNIGHT. BASED ON THIS SCENARIO...WE THINK THE HIGHEST SEVERE WEATHER CHANCES WILL BE THROUGH MIDNIGHT. MIXED LAYER CAPE VALUES WILL BE UP TO 2000 J/KG IN THE SOUTHEAST WITH EFFECTIVE BULK SHEAR VALUES UP TO 45 KT ACROSS MOST OF THE AREA. AS A RESULT...LARGE HAIL UP TO THE SIZE OF HALF DOLLARS AND DAMAGING WINDS IN EXCESS OF 60 MPH WILL BE THE PRIMARY HAZARDS. THE HAIL THREAT WILL LIKELY BE HIGHEST ACROSS THE SOUTHEAST TEXAS PANHANDLE WHERE THE AIR MASS IS MOST UNSTABLE AND HAIL GROWTH CAPE VALUES WILL BE AS HIGH AS 600 J/KG. BELIEVE THE ATMOSPHERE WILL BE WORKED OVER ENOUGH OVERNIGHT THAT THIS MAY LIMIT THE COVERAGE OF ADDITIONAL THUNDERSTORMS. THEREFORE...WE LOWERED POPS FOR THE OVERNIGHT HOURS. THURSDAY-THURSDAY NIGHT: ANOTHER TRICKY FORECAST IS IN STORE FOR TOMORROW AND THE BEST THUNDERSTORM CHANCES WILL LARGELY DEPEND ON WHERE THE SURFACE FRONT SETS UP. THE NAM AND ECMWF KEEP THE FRONT JUST NORTH OF INTERSTATE 40 WHILE THE GFS AND GGEM KEEP THE FRONT ACROSS THE NORTHERN TEXAS PANHANDLE. EXTENSIVE LOW CLOUDS WILL ALSO COMPLICATE HIGH TEMPERATURES DURING THE AFTERNOON WITH HIGHS NEAR 70 EXPECTED IN THE NORTHWEST AND MID 70S IN THE SOUTHEAST. THESE LOW CLOUDS WILL ALSO HAVE A LARGE IMPACT ON HOW UNSTABLE THE ATMOSPHERE CAN BECOME. IF THE LOW CLOUDS ARE STUBBORN TO BREAK...THIS COULD LEAD TO A VERY MARGINAL SEVERE WEATHER EVENT. AT THIS TIME..WE THINK THERE WILL BE ENOUGH BREAKS IN THE CLOUDS TO DESTABILIZE THE ATMOSPHERE SUFFICIENTLY FOR SEVERE STORMS. IN FACT...A FEW SEVERE STORMS CANNOT BE RULED OUT JUST ABOUT ANYWHERE DURING THE AFTERNOON AND EVENING...BUT THE HIGHER PROBABILITIES LOOK TO EXIST SOUTH OF A DALHART TO CANADIAN LINE. DEEP LAYER BULK SHEAR VALUES WILL RANGE BETWEEN 30 AND 40 KT ALONG WITH MIXED LAYER CAPE VALUES UP TO 1000 J/KG. AS A RESULT...LARGE HAIL AND DAMAGING WINDS WILL BE THE PRIMARY HAZARDS. MORE WIDESPREAD RAIN CHANCES LOOK TO EVOLVE DURING THE LATE EVENING AND OVERNIGHT HOURS. LOCALLY HEAVY RAIN WILL ALSO CONTINUE TO BE A CONCERN. FRIDAY-WEDNESDAY: THUNDERSTORMS CHANCES WILL CONTINUE THROUGH SUNDAY NIGHT BEFORE DRIER CONDITIONS RETURN FOR EARLY NEXT WEEK. NO SEVERE WEATHER IS ANTICIPATED DURING THIS TIME FRAME AS THE ENVIRONMENT SHOULD BE WEAKLY UNSTABLE ALONG WITH POOR DEEP LAYER WIND SHEAR IN PLACE. TEMPERATURES WILL BE NEAR TO BELOW NORMAL FRIDAY AND SATURDAY BEFORE A WARMING TREND BEGINS SUNDAY. JACKSON FIRE WEATHER... NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE ANTICIPATED THROUGH WEDNESDAY AS 20-FOOT WINDS WILL REMAIN BELOW 15 MPH AND/OR RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE 20 PERCENT. && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
224 PM EDT THU SEP 27 2012 .SYNOPSIS... A COLD FRONT FROM NEW ENGLAND TO THE OHIO VALLEY WILL MOVE SLOWLY SOUTHEAST TODAY AND TONIGHT. BY FRIDAY EVENING THE FRONT WILL TRAIL FROM THE MID ATLANTIC REGION ACROSS THE SOUTHEAST UNITED STATES. HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM EDT WEDNESDAY... THE EARLY MORNING FORECAST PACKAGE APPEARS TO BE IN GOOD SHAPE... WITH THE OBSERVED HOURLY TEMPERATURE INCREASES ON TRACK TO BE VERY CLOSE TO EXPECTED AFTERNOON HIGHS. DID ADJUST THE AREA OF CLOUD COVER IN THE FORECAST TO BETTER REFLECT LATEST VISIBLE SATELLITE IMAGERY. STARTING TO SEE A FEW RETURNS ON RADAR OVER CENTRAL WEST VIRGINIA...WHICH ARE EXPECTED TO APPROACH OUR WESTERN RIDGELINES BY NOON...SO WILL CONTINUE TO MONITOR THE DEVELOPMENT OF THIS ACTIVITY. AS OF 420 AM EDT WEDNESDAY... THE COLD FRONT EXTENDED FROM MAINE TO A LOW OVER SOUTHERN INDIANA. MODELS MOVE THE SHORT WAVE ASSOCIATED WITH THIS LOW AND THIS WAVE ALONG THE FRONT EAST-NORTHEAST THROUGH THE OHIO VALLEY TODAY. THE FRONT DOES NOT MAKE MUCH PROGRESS SOUTH. STILL EXPECTING CLUSTERS OF SHOWERS AND THUNDERSTORMS ALONG THE LENGTH OF THE BOUNDARY BUT LOCAL WRF AS WELL AS THE RUC AND HRRR DO NOT BRING PRECIPITATION INTO THE WESTERN COUNTY WARNING AREA UNTIL AROUND 20Z. OUT AHEAD OF THE PRECIPITATION WITH THE FRONT...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE SOUTHERN BLUE RIDGE. CONVECTIVE AVAILABLE POTENTIAL ENERGY IN THE WARM SECTOR WILL BE 800-900 J/KG THIS AFTERNOON WITH SOME OF THE MODELS SHOWING A PRE-FRONTAL LEE TROF. OVERALL HAVE SLOWED DOWN BETTER PROBABILITY OF PRECIPITATION UNTIL AFTER 00Z/8PM TONIGHT. TEMPERATURES STARTING IN THE LOWER 50S TO LOWER 60S THIS MORNING. WILL BE ENOUGH SUN THIS MORNING TO BRING HIGH TEMPERATURES ABOVE NORMAL AGAIN. WITH THE INCREASING CLOUD COVER TONIGHT AS WELL AS THE MILD AIR MASS WITH SURFACE DEW POINTS WELL INTO THE 50S TO LOWER 60S...USED WARMEST GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 340 AM EDT THURSDAY... MODELS COMING IN A LITTLE QUICKER WITH THE FRONTAL PASSAGE. MOST MODELS HAVE THE FRONT SLOWLY CROSSING THE AREA FRIDAY AFTERNOON/EVENING AS A SURFACE WAVE TRACKS EAST ACROSS PA/NJ. MODELS...24 HOURS AGO...HAD THE FRONTAL PASSAGE FRIDAY NIGHT INTO SATURDAY MORNING. SHOWERS WILL LIKELY ENTER SOUTHEAST WEST VIRGINIA DURING THE MORNING...THEN TRACK SOUTH ACROSS THE MOUNTAINS AND EVENTUALLY IN THE EAST IN THE AFTERNOON. THE BEST FORCING WILL BE ACROSS THE MOUNTAINS THROUGH EARLY AFTERNOON...THEN OVER SOUTHSIDE VIRGINIA-NORTHERN NORTH CAROLINA LATE AFTERNOON AND EVENING. CONFIDENCE ON SHOWERS MORE SO ACROSS THE WEST. LOWER CONFIDENCE IN THE EAST WITH POSSIBLE RAIN SHADOW AS WEST WINDS QUICKLY ENGULF THE AREA DURING THE AFTERNOON. THE FRONT SINKS INTO THE CAROLINAS FRIDAY NIGHT AND SATURDAY. THIS FRONTAL BOUNDARY COULD RETREAT TO THE NORTH AS A DISTURBANCE TRACKS EAST ALONG THE GULF COAST. RAIN ENTERING THE AREA EARLY IN THE MORNING WILL KEEP TEMPERATURES COOLER ACROSS THE MOUNTAINS FRIDAY BUT COULD PEAK NEAR NORMAL. LATER ARRIVAL OF SHOWERS EAST OF THE BLUE RIDGE COULD PUSH TEMPERATURES ABOVE NORMAL FRIDAY AFTERNOON WITH SOUTHSIDE TOPPING OUT IN THE LOWER 80S. COOLER AIR FILTERS INTO THE REGION SATURDAY WITH 5F BELOW NORMAL HIGHS IN THE WEST TO NEAR NORMAL IN THE EAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 245 PM EDT WEDNESDAY... FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF OUR AREA TO FINISH OUT THE WEEKEND AS DEEP UPPER LOW SPINS ACROSS THE OHIO VALLEY AND EJECTS FINALLY TO THE NORTHEAST BY MONDAY INTO MONDAY NIGHT. THE ECMWF IS FURTHER WEST AND SLOWER THAN THE GFS...AND HOLDS ONTO DEEPER MOISTURE IN THE EAST INTO SUNDAY. GIVEN THE AMPLITUDE OF THE TROUGH WILL LEAN TOWARD ITS SLOWER SOLUTION. THIS WILL KEEP THE THREAT OF SHOWERS AROUND AT LEAST INTO SUNDAY NIGHT BEFORE DEEPER MOISTURE SHIFTS EAST. COLDER POCKET ALOFT WITH THE UPPER LOW SHIFTS CLOSE ENOUGH SOUTH INTO THE CENTRAL APPALACHIANS SUNDAY THAT SOME THUNDER IS POSSIBLE. EARLY NEXT WEEK THE MAIN TROUGH LIFTS OUT BUT A BROAD TROUGH WILL REMAIN FROM THE GREAT LAKES SOUTH INTO THE GULF COASTAL STATES UNTIL TUESDAY...SHIFTING EAST BY MIDWEEK WITH OUR AREA SITUATED ON THE SRN EDGE OF FAST ZONAL FLOW. TUESDAY-WEDNESDAY...WILL SEE HIGH PRESSURE OVER THE AREA. SEASONAL TEMPS ARE EXPECTED THIS PERIOD...ALTHOUGH SUNDAY COULD BE COOLER UNDER MORE CLOUDS AND POP-UP SHOWERS. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 200 PM EDT THURSDAY... ALL LOCATIONS ARE REPORTING VFR CONDITIONS THIS AFTERNOON... CONDITIONS WHICH ARE EXPECTED TO CONTINUE THROUGH THE REMAINDER OF THURSDAY OUTSIDE OF SHOWER AND ISOLATED THUNDERSTORM ACTIVITY. LATEST ROUND OF SHORT RANGE MODELS INDICATE THAT A WEAK LOW PRESSURE SYSTEM WILL RIDE ALONG THE FRONTAL BOUNDARY TO OUR NORTH...TRIGGERING A ROUND OF SHOWERS AND THUNDERSTORMS THAT WILL PASS ACROSS KENTUCKY INTO WESTERN VIRGINIA THIS EVENING. MUCH OF THIS ACTIVITY WILL DIE OFF AS IT PASSES THE RIDGELINES ALONG THE WESTERN BORDER OF THE FORECAST AREA...ENTERING INTO DOWNSLOPE FLOW...BUT A FEW WILL SURVIVE LONG ENOUGH TO AFFECT BLF...LWB AND BCB. MODELS ALSO INDICATE THE POSSIBILITY OF A THUNDERSTORM OR TWO DEVELOPING JUST EAST OF THE BLUE RIDGE AS A WEAK DISTURBANCE ALOFT INTERACTS WITH THE LEE SIDE TROUGH SITUATED OVER THE AREA...ALTHOUGH INSTABILITY WILL BE MODEST AT BEST. CIRRUS WILL REMAIN WIDESPREAD ACROSS THE MOUNTAINS OVERNIGHT... HOWEVER WITH LIGHT SOUTHWESTERLY TO WESTERLY WINDS CARRYING WARM MOIST AIR INTO THE AREA...STILL EXPECT TO SEE ANOTHER ROUND OF PATCHY DENSE FOG DEVELOP...ESPECIALLY AT LWB AND BCB...WHICH COULD FALL TO A QUARTER MILE OR LESS. VISIBILITIES WILL IMPROVE QUICKLY AFTER 28/13Z AS DAYTIME HEATING INCREASES. BY MID FRIDAY MORNING...THE LOW PRESSURE SYSTEM WILL PROGRESS EAST INTO THE LOWER NEW ENGLAND STATES...DRAGGING THE COLD FRONT FURTHER SOUTH ACROSS OUR AREA. ADDITIONAL SHOWER AND ISOLATED THUNDERSTORM ACTIVITY WILL DEVELOP ACROSS OUR AREA AS THE FRONT PASSES THROUGH...WITH LOCALLY MVFR CONDITIONS DEVELOPING IN THIS ACTIVITY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/JH NEAR TERM...AMS/NF SHORT TERM...RCS LONG TERM...WP AVIATION...AMS/NF
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1023 AM EDT THU SEP 27 2012 .SYNOPSIS... A COLD FRONT FROM NEW ENGLAND TO THE OHIO VALLEY WILL MOVE SLOWLY SOUTHEAST TODAY AND TONIGHT. BY FRIDAY EVENING THE FRONT WILL TRAIL FROM THE MID ATLANTIC REGION ACROSS THE SOUTHEAST UNITED STATES. HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM EDT WEDNESDAY... THE EARLY MORNING FORECAST PACKAGE APPEARS TO BE IN GOOD SHAPE... WITH THE OBSERVED HOURLY TEMPERATURE INCREASES ON TRACK TO BE VERY CLOSE TO EXPECTED AFTERNOON HIGHS. DID ADJUST THE AREA OF CLOUD COVER IN THE FORECAST TO BETTER REFLECT LATEST VISIBLE SATELLITE IMAGERY. STARTING TO SEE A FEW RETURNS ON RADAR OVER CENTRAL WEST VIRGINIA...WHICH ARE EXPECTED TO APPROACH OUR WESTERN RIDGELINES BY NOON...SO WILL CONTINUE TO MONITOR THE DEVELOPMENT OF THIS ACTIVITY. AS OF 420 AM EDT WEDNESDAY... THE COLD FRONT EXTENDED FROM MAINE TO A LOW OVER SOUTHERN INDIANA. MODELS MOVE THE SHORT WAVE ASSOCIATED WITH THIS LOW AND THIS WAVE ALONG THE FRONT EAST-NORTHEAST THROUGH THE OHIO VALLEY TODAY. THE FRONT DOES NOT MAKE MUCH PROGRESS SOUTH. STILL EXPECTING CLUSTERS OF SHOWERS AND THUNDERSTORMS ALONG THE LENGTH OF THE BOUNDARY BUT LOCAL WRF AS WELL AS THE RUC AND HRRR DO NOT BRING PRECIPITATION INTO THE WESTERN COUNTY WARNING AREA UNTIL AROUND 20Z. OUT AHEAD OF THE PRECIPITATION WITH THE FRONT...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE SOUTHERN BLUE RIDGE. CONVECTIVE AVAILABLE POTENTIAL ENERGY IN THE WARM SECTOR WILL BE 800-900 J/KG THIS AFTERNOON WITH SOME OF THE MODELS SHOWING A PRE-FRONTAL LEE TROF. OVERALL HAVE SLOWED DOWN BETTER PROBABILITY OF PRECIPITATION UNTIL AFTER 00Z/8PM TONIGHT. TEMPERATURES STARTING IN THE LOWER 50S TO LOWER 60S THIS MORNING. WILL BE ENOUGH SUN THIS MORNING TO BRING HIGH TEMPERATURES ABOVE NORMAL AGAIN. WITH THE INCREASING CLOUD COVER TONIGHT AS WELL AS THE MILD AIR MASS WITH SURFACE DEW POINTS WELL INTO THE 50S TO LOWER 60S...USED WARMEST GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 340 AM EDT THURSDAY... MODELS COMING IN A LITTLE QUICKER WITH THE FRONTAL PASSAGE. MOST MODELS HAVE THE FRONT SLOWLY CROSSING THE AREA FRIDAY AFTERNOON/EVENING AS A SURFACE WAVE TRACKS EAST ACROSS PA/NJ. MODELS...24 HOURS AGO...HAD THE FRONTAL PASSAGE FRIDAY NIGHT INTO SATURDAY MORNING. SHOWERS WILL LIKELY ENTER SOUTHEAST WEST VIRGINIA DURING THE MORNING...THEN TRACK SOUTH ACROSS THE MOUNTAINS AND EVENTUALLY IN THE EAST IN THE AFTERNOON. THE BEST FORCING WILL BE ACROSS THE MOUNTAINS THROUGH EARLY AFTERNOON...THEN OVER SOUTHSIDE VIRGINIA-NORTHERN NORTH CAROLINA LATE AFTERNOON AND EVENING. CONFIDENCE ON SHOWERS MORE SO ACROSS THE WEST. LOWER CONFIDENCE IN THE EAST WITH POSSIBLE RAIN SHADOW AS WEST WINDS QUICKLY ENGULF THE AREA DURING THE AFTERNOON. THE FRONT SINKS INTO THE CAROLINAS FRIDAY NIGHT AND SATURDAY. THIS FRONTAL BOUNDARY COULD RETREAT TO THE NORTH AS A DISTURBANCE TRACKS EAST ALONG THE GULF COAST. RAIN ENTERING THE AREA EARLY IN THE MORNING WILL KEEP TEMPERATURES COOLER ACROSS THE MOUNTAINS FRIDAY BUT COULD PEAK NEAR NORMAL. LATER ARRIVAL OF SHOWERS EAST OF THE BLUE RIDGE COULD PUSH TEMPERATURES ABOVE NORMAL FRIDAY AFTERNOON WITH SOUTHSIDE TOPPING OUT IN THE LOWER 80S. COOLER AIR FILTERS INTO THE REGION SATURDAY WITH 5F BELOW NORMAL HIGHS IN THE WEST TO NEAR NORMAL IN THE EAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 245 PM EDT WEDNESDAY... FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF OUR AREA TO FINISH OUT THE WEEKEND AS DEEP UPPER LOW SPINS ACROSS THE OHIO VALLEY AND EJECTS FINALLY TO THE NORTHEAST BY MONDAY INTO MONDAY NIGHT. THE ECMWF IS FURTHER WEST AND SLOWER THAN THE GFS...AND HOLDS ONTO DEEPER MOISTURE IN THE EAST INTO SUNDAY. GIVEN THE AMPLITUDE OF THE TROUGH WILL LEAN TOWARD ITS SLOWER SOLUTION. THIS WILL KEEP THE THREAT OF SHOWERS AROUND AT LEAST INTO SUNDAY NIGHT BEFORE DEEPER MOISTURE SHIFTS EAST. COLDER POCKET ALOFT WITH THE UPPER LOW SHIFTS CLOSE ENOUGH SOUTH INTO THE CENTRAL APPALACHIANS SUNDAY THAT SOME THUNDER IS POSSIBLE. EARLY NEXT WEEK THE MAIN TROUGH LIFTS OUT BUT A BROAD TROUGH WILL REMAIN FROM THE GREAT LAKES SOUTH INTO THE GULF COASTAL STATES UNTIL TUESDAY...SHIFTING EAST BY MIDWEEK WITH OUR AREA SITUATED ON THE SRN EDGE OF FAST ZONAL FLOW. TUESDAY-WEDNESDAY...WILL SEE HIGH PRESSURE OVER THE AREA. SEASONAL TEMPS ARE EXPECTED THIS PERIOD...ALTHOUGH SUNDAY COULD BE COOLER UNDER MORE CLOUDS AND POP-UP SHOWERS. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... AS OF 735 AM EDT THURSDAY... PATCHY MORNING FOG WITH LIFR TO MVFR VISIBILITIES WILL MIX OUT BY 14Z/10AM. A COLD FRONT AND PERSISTENT BAROCLINIC ZONE TO THE NORTH OF THE AREA WILL DRIFT INTO THE CWA DURING THE AFTERNOON. LOCAL WRF MODELS PUT TIMING OF THE THUNDERSTORMS AFTER 20Z/4PM AT BLF AND LWB. SO HAVE SLOWED DOWN ARRIVAL TIME OF PRECIPITATION IN THE BLF/LWB/ROA AND BCB TAFS. LOCATION OF THE SURFACE COLD FRONT WILL HAVE A BIG INFLUENCE ON THE PROBABILITY OF SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA. THE BEST PROBABILITY WILL BE TONIGHT THROUGH FRIDAY EVENING. MVFR CEILINGS AND VISIBILITIES WILL BE POSSIBLE IN ANY OF THE STRONGER STORMS ALONG WITH THE CHANCE FOR GUSTY WINDS. AS THE FRONT DRIFTS SOUTH OF THE REGION SATURDAY THROUGH MONDAY EXPECT DAYTIME VFR CONDITIONS. FOG WILL STILL BE LIKELY EACH NIGHT IN THE FAVORED VALLEY LOCATIONS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/JH NEAR TERM...AMS/NF SHORT TERM...RCS LONG TERM...WP AVIATION...AMS/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
743 AM EDT THU SEP 27 2012 .SYNOPSIS... A COLD FRONT FROM NEW ENGLAND TO THE OHIO VALLEY WILL MOVE SLOWLY SOUTHEAST TODAY AND TONIGHT. BY FRIDAY EVENING THE FRONT WILL TRAIL FROM THE MID ATLANTIC REGION ACROSS THE SOUTHEAST UNITED STATES. HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 420 AM EDT WEDNESDAY... THE COLD FRONT EXTENDED FROM MAINE TO A LOW OVER SOUTHERN INDIANA. MODELS MOVE THE SHORT WAVE ASSOCIATED WITH THIS LOW AND THIS WAVE ALONG THE FRONT EAST-NORTHEAST THROUGH THE OHIO VALLEY TODAY. THE FRONT DOES NOT MAKE MUCH PROGRESS SOUTH. STILL EXPECTING CLUSTERS OF SHOWERS AND THUNDERSTORMS ALONG THE LENGTH OF THE BOUNDARY BUT LOCAL WRF AS WELL AS THE RUC AND HRRR DO NOT BRING PRECIPITATION INTO THE WESTERN COUNTY WARNING AREA UNTIL AROUND 20Z. OUT AHEAD OF THE PRECIPITATION WITH THE FRONT...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE SOUTHERN BLUE RIDGE. CONVECTIVE AVAILABLE POTENTIAL ENERGY IN THE WARM SECTOR WILL BE 800-900 J/KG THIS AFTERNOON WITH SOME OF THE MODELS SHOWING A PRE-FRONTAL LEE TROF. OVERALL HAVE SLOWED DOWN BETTER PROBABILITY OF PRECIPITATION UNTIL AFTER 00Z/8PM TONIGHT. TEMPERATURES STARTING IN THE LOWER 50S TO LOWER 60S THIS MORNING. WILL BE ENOUGH SUN THIS MORNING TO BRING HIGH TEMPERATURES ABOVE NORMAL AGAIN. WITH THE INCREASING CLOUD COVER TONIGHT AS WELL AS THE MILD AIR MASS WITH SURFACE DEW POINTS WELL INTO THE 50S TO LOWER 60S...USED WARMEST GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 340 AM EDT THURSDAY... MODELS COMING IN A LITTLE QUICKER WITH THE FRONTAL PASSAGE. MOST MODELS HAVE THE FRONT SLOWLY CROSSING THE AREA FRIDAY AFTERNOON/EVENING AS A SURFACE WAVE TRACKS EAST ACROSS PA/NJ. MODELS...24 HOURS AGO...HAD THE FRONTAL PASSAGE FRIDAY NIGHT INTO SATURDAY MORNING. SHOWERS WILL LIKELY ENTER SOUTHEAST WEST VIRGINIA DURING THE MORNING...THEN TRACK SOUTH ACROSS THE MOUNTAINS AND EVENTUALLY IN THE EAST IN THE AFTERNOON. THE BEST FORCING WILL BE ACROSS THE MOUNTAINS THROUGH EARLY AFTERNOON...THEN OVER SOUTHSIDE VIRGINIA-NORTHERN NORTH CAROLINA LATE AFTERNOON AND EVENING. CONFIDENCE ON SHOWERS MORE SO ACROSS THE WEST. LOWER CONFIDENCE IN THE EAST WITH POSSIBLE RAIN SHADOW AS WEST WINDS QUICKLY ENGULF THE AREA DURING THE AFTERNOON. THE FRONT SINKS INTO THE CAROLINAS FRIDAY NIGHT AND SATURDAY. THIS FRONTAL BOUNDARY COULD RETREAT TO THE NORTH AS A DISTURBANCE TRACKS EAST ALONG THE GULF COAST. RAIN ENTERING THE AREA EARLY IN THE MORNING WILL KEEP TEMPERATURES COOLER ACROSS THE MOUNTAINS FRIDAY BUT COULD PEAK NEAR NORMAL. LATER ARRIVAL OF SHOWERS EAST OF THE BLUE RIDGE COULD PUSH TEMPERATURES ABOVE NORMAL FRIDAY AFTERNOON WITH SOUTHSIDE TOPPING OUT IN THE LOWER 80S. COOLER AIR FILTERS INTO THE REGION SATURDAY WITH 5F BELOW NORMAL HIGHS IN THE WEST TO NEAR NORMAL IN THE EAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 245 PM EDT WEDNESDAY... FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF OUR AREA TO FINISH OUT THE WEEKEND AS DEEP UPPER LOW SPINS ACROSS THE OHIO VALLEY AND EJECTS FINALLY TO THE NORTHEAST BY MONDAY INTO MONDAY NIGHT. THE ECMWF IS FURTHER WEST AND SLOWER THAN THE GFS...AND HOLDS ONTO DEEPER MOISTURE IN THE EAST INTO SUNDAY. GIVEN THE AMPLITUDE OF THE TROUGH WILL LEAN TOWARD ITS SLOWER SOLUTION. THIS WILL KEEP THE THREAT OF SHOWERS AROUND AT LEAST INTO SUNDAY NIGHT BEFORE DEEPER MOISTURE SHIFTS EAST. COLDER POCKET ALOFT WITH THE UPPER LOW SHIFTS CLOSE ENOUGH SOUTH INTO THE CENTRAL APPALACHIANS SUNDAY THAT SOME THUNDER IS POSSIBLE. EARLY NEXT WEEK THE MAIN TROUGH LIFTS OUT BUT A BROAD TROUGH WILL REMAIN FROM THE GREAT LAKES SOUTH INTO THE GULF COASTAL STATES UNTIL TUESDAY...SHIFTING EAST BY MIDWEEK WITH OUR AREA SITUATED ON THE SRN EDGE OF FAST ZONAL FLOW. TUESDAY-WEDNESDAY...WILL SEE HIGH PRESSURE OVER THE AREA. SEASONAL TEMPS ARE EXPECTED THIS PERIOD...ALTHOUGH SUNDAY COULD BE COOLER UNDER MORE CLOUDS AND POP-UP SHOWERS. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AS OF 735 AM EDT THURSDAY... PATCHY MORNING FOG WITH LIFR TO MVFR VISIBILITIES WILL MIX OUT BY 14Z/10AM. A COLD FRONT AND PERSISTENT BAROCLINIC ZONE TO THE NORTH OF THE AREA WILL DRIFT INTO THE CWA DURING THE AFTERNOON. LOCAL WRF MODELS PUT TIMING OF THE THUNDERSTORMS AFTER 20Z/4PM AT BLF AND LWB. SO HAVE SLOWED DOWN ARRIVAL TIME OF PRECIPITATION IN THE BLF/LWB/ROA AND BCB TAFS. LOCATION OF THE SURFACE COLD FRONT WILL HAVE A BIG INFLUENCE ON THE PROBABILITY OF SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA. THE BEST PROBABILITY WILL BE TONIGHT THROUGH FRIDAY EVENING. MVFR CEILINGS AND VISIBILITIES WILL BE POSSIBLE IN ANY OF THE STRONGER STORMS ALONG WITH THE CHANCE FOR GUSTY WINDS. AS THE FRONT DRIFTS SOUTH OF THE REGION SATURDAY THROUGH MONDAY EXPECT DAYTIME VFR CONDITIONS. FOG WILL STILL BE LIKELY EACH NIGHT IN THE FAVORED VALLEY LOCATIONS. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/JH NEAR TERM...AMS SHORT TERM...RCS LONG TERM...WP AVIATION...AMS/RAB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
438 AM EDT THU SEP 27 2012 .SYNOPSIS... A COLD FRONT FROM NEW ENGLAND TO THE OHIO VALLEY WILL MOVE SLOWLY SOUTHEAST TODAY AND TONIGHT. BY FRIDAY EVENING THE FRONT WILL TRAIL FROM THE MID ATLANTIC REGION ACROSS THE SOUTHEAST UNITED STATES. HIGH PRESSURE WILL BUILD IN EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 420 AM EDT WEDNESDAY... THE COLD FRONT EXTENDED FROM MAINE TO A LOW OVER SOUTHERN INDIANA. MODELS MOVE THE SHORT WAVE ASSOCIATED WITH THIS LOW AND THIS WAVE ALONG THE FRONT EAST-NORTHEAST THROUGH THE OHIO VALLEY TODAY. THE FRONT DOES NOT MAKE MUCH PROGRESS SOUTH. STILL EXPECTING CLUSTERS OF SHOWERS AND THUNDERSTORMS ALONG THE LENGTH OF THE BOUNDARY BUT LOCAL WRF AS WELL AS THE RUC AND HRRR DO NOT BRING PRECIPITATION INTO THE WESTERN COUNTY WARNING AREA UNTIL AROUND 20Z. OUT AHEAD OF THE PRECIPITATION WITH THE FRONT...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE SOUTHERN BLUE RIDGE. CONVECTIVE AVAILABLE POTENTIAL ENERGY IN THE WARM SECTOR WILL BE 800-900 J/KG THIS AFTERNOON WITH SOME OF THE MODELS SHOWING A PRE-FRONTAL LEE TROF. OVERALL HAVE SLOWED DOWN BETTER PROBABILITY OF PRECIPITATION UNTIL AFTER 00Z/8PM TONIGHT. TEMPERATURES STARTING IN THE LOWER 50S TO LOWER 60S THIS MORNING. WILL BE ENOUGH SUN THIS MORNING TO BRING HIGH TEMPERATURES ABOVE NORMAL AGAIN. WITH THE INCREASING CLOUD COVER TONIGHT AS WELL AS THE MILD AIR MASS WITH SURFACE DEW POINTS WELL INTO THE 50S TO LOWER 60S...USED WARMEST GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 340 AM EDT THURSDAY... MODELS COMING IN A LITTLE QUICKER WITH THE FRONTAL PASSAGE. MOST MODELS HAVE THE FRONT SLOWLY CROSSING THE AREA FRIDAY AFTERNOON/EVENING AS A SURFACE WAVE TRACKS EAST ACROSS PA/NJ. MODELS...24 HOURS AGO...HAD THE FRONTAL PASSAGE FRIDAY NIGHT INTO SATURDAY MORNING. SHOWERS WILL LIKELY ENTER SOUTHEAST WEST VIRGINIA DURING THE MORNING...THEN TRACK SOUTH ACROSS THE MOUNTAINS AND EVENTUALLY IN THE EAST IN THE AFTERNOON. THE BEST FORCING WILL BE ACROSS THE MOUNTAINS THROUGH EARLY AFTERNOON...THEN OVER SOUTHSIDE VIRGINIA-NORTHERN NORTH CAROLINA LATE AFTERNOON AND EVENING. CONFIDENCE ON SHOWERS MORE SO ACROSS THE WEST. LOWER CONFIDENCE IN THE EAST WITH POSSIBLE RAIN SHADOW AS WEST WINDS QUICKLY ENGULF THE AREA DURING THE AFTERNOON. THE FRONT SINKS INTO THE CAROLINAS FRIDAY NIGHT AND SATURDAY. THIS FRONTAL BOUNDARY COULD RETREAT TO THE NORTH AS A DISTURBANCE TRACKS EAST ALONG THE GULF COAST. RAIN ENTERING THE AREA EARLY IN THE MORNING WILL KEEP TEMPERATURES COOLER ACROSS THE MOUNTAINS FRIDAY BUT COULD PEAK NEAR NORMAL. LATER ARRIVAL OF SHOWERS EAST OF THE BLUE RIDGE COULD PUSH TEMPERATURES ABOVE NORMAL FRIDAY AFTERNOON WITH SOUTHSIDE TOPPING OUT IN THE LOWER 80S. COOLER AIR FILTERS INTO THE REGION SATURDAY WITH 5F BELOW NORMAL HIGHS IN THE WEST TO NEAR NORMAL IN THE EAST. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 245 PM EDT WEDNESDAY... FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF OUR AREA TO FINISH OUT THE WEEKEND AS DEEP UPPER LOW SPINS ACROSS THE OHIO VALLEY AND EJECTS FINALLY TO THE NORTHEAST BY MONDAY INTO MONDAY NIGHT. THE ECMWF IS FURTHER WEST AND SLOWER THAN THE GFS...AND HOLDS ONTO DEEPER MOISTURE IN THE EAST INTO SUNDAY. GIVEN THE AMPLITUDE OF THE TROUGH WILL LEAN TOWARD ITS SLOWER SOLUTION. THIS WILL KEEP THE THREAT OF SHOWERS AROUND AT LEAST INTO SUNDAY NIGHT BEFORE DEEPER MOISTURE SHIFTS EAST. COLDER POCKET ALOFT WITH THE UPPER LOW SHIFTS CLOSE ENOUGH SOUTH INTO THE CENTRAL APPALACHIANS SUNDAY THAT SOME THUNDER IS POSSIBLE. EARLY NEXT WEEK THE MAIN TROUGH LIFTS OUT BUT A BROAD TROUGH WILL REMAIN FROM THE GREAT LAKES SOUTH INTO THE GULF COASTAL STATES UNTIL TUESDAY...SHIFTING EAST BY MIDWEEK WITH OUR AREA SITUATED ON THE SRN EDGE OF FAST ZONAL FLOW. TUESDAY-WEDNESDAY...WILL SEE HIGH PRESSURE OVER THE AREA. SEASONAL TEMPS ARE EXPECTED THIS PERIOD...ALTHOUGH SUNDAY COULD BE COOLER UNDER MORE CLOUDS AND POP-UP SHOWERS. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... AS OF 135 AM EDT THURSDAY... MID AND HIGH CLOUDS COMING FROM THE THUNDERSTORMS IN THE OHIO VALLEY MAY LIMIT THE EXTENT OF THE FOG THIS MORNING. HOWEVER... OBSERVATIONS ALREADY SHOWED A SMALL TEMPERATURE/DEW POINT SPREAD AT AREA AIRPORTS. HAVE LEFT MVFR FOG IN EARLY THIS MORNING FOR LYH...DAN AND BCB. MODERATE CONFIDENCE THAT LWB WILL OCCASIONALLY DROP TO LIFR VISIBILITY AND CEILINGS. PERSISTENT BAROCLINIC ZONE TO THE NORTH OF THE AREA WILL DRIFT INTO THE CWA DURING THE AFTERNOON. THUNDERSTORMS APPEAR TO BE A GOOD BET FOR MUCH OF THE CWA BY LATE AFTERNOON. LOCATION OF THE SURFACE COLD FRONT WILL HAVE A BIG INFLUENCE ON THE PROBABILITY OF SHOWERS AND THUNDERSTORMS IN THE FORECAST AREA THIS AFTERNOON AND TONIGHT. AT THIS POINT...ALL AREAS SHOULD SEE SHRA/TSRA ACTIVITY IN THE 20Z-06Z TIME FRAME FROM W-E...WITH THE MOST INTENSE ACTIVITY LIKELY FROM LWB-BLF IN THE LATE AFTERNOON. MVFR CONDITIONS AND A GREATER COVERAGE OF SHOWERS AND STORMS ARE EXPECTED TONIGHT INTO THE START OF THE WEEKEND AS THE FRONT MOVES INTO THE REGION...STALLS...AND THEN HEADS SOUTH OF THE AREA. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/JH NEAR TERM...AMS SHORT TERM...RCS LONG TERM...WP AVIATION...AMS/RAB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
126 AM EDT SAT SEP 29 2012 .SYNOPSIS... THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ON THE INCREASE THIS WEEKEND AS A COLD FRONT STALLS ACROSS THE EASTERN CAROLINAS. NEXT WEEK WILL REMAIN UNSETTLED AS LOW PRESSURE DEVELOPS ALONG THE GULF COAST AND MOVES ACROSS THE WESTERN CAROLINAS. A COLD FRONT WILL CROSS THE AREA BY LATE WEEK BRINGING DRIER AND COOLER WEATHER. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 130 AM SATURDAY...RADAR LOOPS SHOW NEW SHOWERS DEVELOPING IN THE ZONE BETWEEN CHARLOTTE AND SOUTHERN PINES. MOST OF THIS WILL REMAIN NORTH OF OUR FORECAST AREA BUT THE SMALL (20 PERCENT) POPS CURRENTLY IN PLACE ACROSS THE DARLINGTON-BENNETTSVILLE-LUMBERTON- ELIZABETHTOWN CORRIDOR LOOK GOOD. OTHER THAN A FEW SMALL TWEAKS TO TEMPERATURES AND DEWPOINTS BASED ON LATEST OBSERVATIONS...NO CHANGES HAVE BEEN MADE. PREVIOUS DISCUSSION FROM 1030 PM FOLLOWS... CURRENT CONVECTION AHEAD OF THE COLD FRONT CONTINUES TO DIMINISH IN AREAL COVERAGE DURING THIS EVENING...AND SHOULD CONTINUE THIS TREND OVERNIGHT DUE TO INSTABILITY HAVING WEAKENED. THE OUTFLOWS FROM THE EARLIER STORMS UPSTREAM HAVE REACHED THE NORTHERN 1/3RD OF THE FA. LATEST HRRR HAS NOW BACKED OFF WITH PCPN COVERAGE OVERNIGHT. WILL HOWEVER CONTINUE A SLIGHT CHANCE OF PCPN FOR THE NORTHERN 1/4TH TO 1/3RD PORTIONS OF THE ILM CWA...FOR THE REMAINDER OF THE OVERNIGHT. TWEAKED MIN TEMPS UP SOME WHERE THE THICKER AND MORE OPAQUE CLOUDINESS WILL RESIDE. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 3 PM FRIDAY...MID LEVEL TROUGH DEEPENING OVER EASTERN GREAT LAKES IN RESPONSE TO VERY COLD -24C 500HPA SLIDING DOWN WEST SIDE OF THE TROUGH. COLD FRONT WILL BE DRIVEN INTO THE AREA BY BY LATE AFTERNOON. FAIRLY GOOD FORCING WILL SPREAD ACROSS THE AREA FROM THE NORTHWEST DUE TO HEIGHT FALLS AND INCREASING JETTING ALOFT...AND THERE IS EVEN SOME WEAK LOW LEVEL WARM AIR ADVECTION. A LATE DAY VORT MAX MAY ACT TO ENHANCE POPS ALONG THE COAST...BUT OVERALL PRECIP CHANCES AND AMOUNTS WILL BE SOMEWHAT MARGINALIZED BY A LACK OF PRE-FRONTAL MOISTURE ADVECTION DUE TO THE ABSENCE OF A STRONG HIGH IN THE WESTERN ATLANTIC. ANOTHER MUCH WEAKER UPPER DISTURBANCE WILL DROP INTO THE SOUTHERN MISSISSIPPI VALLEY SATURDAY NIGHT INTO SUNDAY. THIS WILL INCITE CYCLOGENESIS OVER THE NORTHWESTERN GULF OF MEXICO. AS THIS SYSTEM MOVES EASTWARD ACROSS THE GULF IT WILL HALT THE PROGRESS OF THE BOUNDARY ALONG THE COAST OF THE CAROLINAS...AS WILL THE LIFTING OUT OF THE MAIN UPPER LOW MOVING EAST OUT OF THE GREAT LAKES INTO THE NORTHEASTERN U.S. THIS WILL KEEP UNSETTLED WEATHER IN THE FORECAST BUT DUE TO AN OVERALL DECREASE IN FORCING MECHANISM STRENGTH BOTH IN THE LOWER AND MID LEVELS SUNDAY APPEARS TO OFFER LESS RAINFALL OPPORTUNITY. WHETHER OR NOT THIS COMES TO PASS HINGES MAINLY ON THE SPEED AT WHICH THE OFFSHORE FRONT RETURNS AS A WARM FRONT...WHICH IS HIGHLY UNCERTAIN AND POORLY AGREED UPON BY VARIOUS GUIDANCE. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 PM FRIDAY...ACTIVE PATTERN THROUGH THE FIRST HALF OF THE WEEK AS SOUTHERN STREAM VORT SPAWNS GULF COAST CYCLOGENESIS ON MONDAY. AS THE HIGHLY AMPLIFIED 500MB TROUGH AXIS MOVES ONLY VERY SLOWLY EAST THROUGH THE TN VLY...THIS LOW WILL TRAVERSE UP THROUGH THE SPINE OF THE APPALACHIAN RANGE AND OFF THE MID-ATLANTIC COAST BY THURSDAY. WARM FRONT STRETCHING FROM THIS LOW WILL PUSH THROUGH THE CWA VERY EARLY MONDAY LEAVING DEEP AND MOIST SOUTHERLY FLOW ACROSS THE REGION. ALTHOUGH CLOUD COVER WILL BE QUITE SIGNIFICANT MON-WED...THE DEEP MOIST FLOW COMBINED WITH MDT STEEP ML LAPSE RATES THANKS TO 500MB TROUGHING...WILL CREATE SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY...FAVORED DURING THE AFTNS. COLD FRONT PUSHES THROUGH ON WEDNESDAY AFTN...LEADING TO A DRIER END OF THE WEEK. CAA HOLDS OFF UNTIL FRIDAY HOWEVER BEHIND A SECONDARY /DRY/ COLD FRONT. TEMPS MONDAY WILL BE RIGHT AROUND CLIMO...BUT WARM TO WELL ABOVE FOR MID-WEEK THANKS TO THE WARM SOUTHERLY FLOW. TEMPS WILL RETURN TO NORMAL OR SLIGHTLY BELOW FOR THE END OF THE WEEK. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 06Z...RADAR IMAGERY INDICATES SEVERAL CLUSTERS OF SHOWERS HAVE DEVELOPED FROM CHARLOTTE EAST TO SOUTHERN PINES NC...WITH ADDITIONAL WEAKER SHOWER ACTIVITY JUST SOUTH OF COLUMBIA SC. A GENERAL EASTWARD MOVEMENT OF THESE SHOWERS SHOULD KEEP THEM AWAY FROM OUR AIRPORTS...BUT ADDITIONAL SHOWER DEVELOPMENT MAY BRING ACTIVITY IN THE LBT OR FLO VICINITY IN THE NEXT SEVERAL HOURS. VFR CONDITIONS SHOULD PREVAIL BUT VSBYS MAY TEMPO FALL TO 3-5SM IN BR THROUGH DAYBREAK. EXPECT INCREASING CLOUD COVER AFTER DAYBREAK AHEAD OF AN APPROACHING COLD FRONT...WITH TEMPO SUB-VFR CONDITIONS POSSIBLE AS SHOWERS INCREASE IN COVERAGE THROUGHOUT THE DAY WITH ISOLATED AFTERNOON THUNDERSTORMS PSBL. LIGHT SOUTHWEST SFC WINDS THROUGH THE MORNING HOURS WILL BECOME SOUTH IN THE AFTERNOON...WITH SUSTAINED WINDS AOB 10 KTS. EXTENDED OUTLOOK...POTENTIAL MORNING FOG/STRATUS SUNDAY MORNING MAY REDUCE CIGS/VSBYS TO IFR LEVELS. UNSETTLED WEATHER ASSOCIATED WITH A STALLED FRONTAL BOUNDARY COULD PRODUCE PERIODS OF TEMPO SUB-VFR CONDITIONS ACROSS THE AREA THROUGH WEDNESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 130 AM SATURDAY...WINDS AND SEAS ARE IN-LINE WITH THE PREVIOUS FORECAST. NO CHANGES ARE NEEDED. PREVIOUS DISCUSSION FROM 1030 PM FOLLOWS... A WEAK COLD FRONT WILL BE APPROACHING THE WATERS FROM THE NW LATE TONIGHT AND SAT. DO NOT EXPECT ANY SFC PRESSURE GRADIENT TO DEVELOP AHEAD OF IT...AND AS A RESULT WIND SPEEDS OF 10 KT OR LESS LOOK AOK. IN ADDITION...A WEAK SFC PRESSURE PATTERN AHEAD OF THE FRONT WILL ALSO AFFECT THE ILM WATERS OVERNIGHT INTO SATURDAY. COULD GO VARIABLE IN DIRECTION. AFTER LOOKING AT THE LATEST NAM SFC PRESSURE PATTERN...WILL INDICATE S OR SW INITIALLY...BECOMING WSW OVERNIGHT. A NADINE WAVE TRAIN IDENTIFIED BY THE INCREASED PERIODS OF 10-12 SECONDS WILL BE APPROACHING THE ILM WATERS FROM THE ENE OVERNIGHT...AND LIKELY AFFECTING THE ILM WATERS LATER ON SATURDAY. SIG. SEAS TONIGHT WILL BASICALLY RUN A SOLID 2 FEET AND COMPRISED MAINLY FROM AN EASTERLY SWELL AT 8-9 SECOND PERIODS. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 300 PM FRIDAY...COLD FRONT MOVES INTO THE AREA LATER SATURDAY. THIS WILL ONLY BRING ABOUT A MARGINAL INCREASE IN THE WINDS AND SEAS FROM THE PREEXISTING VERY TRANQUIL CONDITIONS THAT HAVE BEEN IN PLACE FOR SOME TIME. EXPECTING SW WINDS TO INCREASE TO JUST 10 15KT. BEING LARGELY COAST-PARALLEL THIS WILL BUILD SEAS UP TO 3 FT ALONG THE OUTER REACHES OF THE 20NM FORECAST ZONES. THE FRONT WILL BE DECELERATING ANY MAY VERY WELL STALL SOMEWHERE QUITE CLOSE TO THE COASTAL WATERS FORECAST ZONES...LEADING TO A LITTLE UNCERTAINTY IN THE WIND AND RESULTING SEAS FORECAST. AT THE CURRENT TIME IT APPEARS THAT THE BOUNDARY WILL HEAD BACK TO THE NORTH BY SUNDAY ALLOWING FOR A RETURN OF A SOUTHERLY FLOW...AT LEAST FOR PART IF NOT ALL OF THE AREA. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 300 PM FRIDAY...WARM FRONT WILL BE CROSSING THE WATERS AT THE START OF THE PERIOD...VEERING WINDS TO THE SOUTH WITH INCREASING SPEEDS. WINDS OF 5-10 KTS FROM THE SE WILL QUICKLY BECOME SOUTHERLY AT 10-15 KTS BY LATE MONDAY...AND PERSIST THROUGH EARLY WEDNESDAY. WEAK COLD FRONT APPROACHES EARLY WEDNESDAY AND DISSIPATES OVER THE WATERS...TURNING WINDS BRIEFLY TO THE SW BEFORE BACKING TO THE SOUTH ONCE AGAIN AROUND 10 KTS. WINDS WILL TURN TO THE WEST BY THE END OF THE PERIOD AS A STRONGER SURGE OF DRY AIR PUSHES ACROSS THE WATERS. SEAS INITIALLY 1-2 FT WILL BUILD QUICKLY TO 2-4 FT BY LATE MONDAY AND CONTINUE AT THESE AMPLITUDES THROUGH WEDNESDAY THANKS TO THE STRONG SOUTHERLY WINDS. AS WINDS VEER MORE TO THE WEST LATE WEDNESDAY...SEAS DECREASE TO 2-3 FT AS HIGHEST WAVES GET PUSHED AWAY FROM SHORE. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...JDW NEAR TERM...DCH/TRA SHORT TERM...MBB LONG TERM...JDW AVIATION...BJR/TRA
AREA FORECAST DISCUSSION
NWS MIAMI FL
1009 AM EDT SAT SEP 29 2012 .UPDATE...NO CHANGES ARE FORTHCOMING IN THE MORNING UPDATES. THE MID/UPPER LOW THAT WAS OVER SOUTH FLORIDA YESTERDAY AND GENERATED VERY COLD TEMPERATURES ALOFT HAS MOVE SOUTH OF THE REGION WITH THE 12Z MFL SOUNDING INDICATING MUCH WARMER CONDITIONS HAVE RETURNED WITH 3 DEGREES CELSIUS OF WARMING AT 50H. THE MID LEVEL LAPSE RATES ARE ALSO MUCH LESS IMPRESSIVE. ALL OF THIS WILL INHIBIT THUNDERSTORM GROWTH THIS AFTERNOON AND THE HRRR SHOWS MINIMAL COVERAGE WHICH SEEMS REASONABLE. SO THE 30 PERCENT POPS LOOK OK AT THIS TIME WITH THE MARINE ZONES ALSO IN GOOD SHAPE. KOB && .PREV DISCUSSION... /ISSUED 727 AM EDT SAT SEP 29 2012/ AVIATION... WIDELY SCATTERED SHRA/ISOLATED TSRA MOVING W THROUGH THE ATLC WATERS AND OCCASIONALLY ONSHORE. AT THIS TIME VCSH IN E COAST TAFS THROUGH 17Z. E COAST SEA BREEZE WILL BE ESTABLISHED AND SCATTERED TSRA WILL DEVELOP ALONG THE SEA BREEZE AND THE CONVECTIVE ACTIVITY SHOULD BE TO THE W OF TERMINALS AND POSSIBLY TOO FAR INLAND TO AFFECT ANY ONE SITE BUT VCTS IN TAFS THROUGH 21Z. AT KAPF...VCTS AFT 18Z THROUGH 30/00Z AS TSRA DEVELOPING CLOSER TO THAT AREA. LIGHT WINDS AT SUNRISE WILL BECOME EASTERLY TO NEAR 10 KNOTS ALL TERMINALS AFT 14Z. AT KAPF...CURRENT SURFACE WIND E AROUND 5 KNOTS BECOMING AFT 13Z ESE THEN SHIFTING W TO 10 KNOTS AFT 17Z AS W COAST SEA BREEZE DEVELOPS. PREV DISCUSSION... /ISSUED 429 AM EDT SAT SEP 29 2012/ DISCUSSION... A TROUGH OF LOW PRESSURE IS CURRENTLY LOCATED OVER EASTERN CANADA EXTENDING OVER THE NORTHEASTERN US. A RIDGE OF HIGH PRESSURE OCCUPIES PART OF WESTERN CANADA AND THE WESTERN US. CURRENT UPPER LEVEL WINDS SHOW AN AREA OF HIGH PRESSURE IN THE UPPER LEVELS OF THE ATMOSPHERE OVER NORTHERN MEXICO AND THE SOUTH CENTRAL PORTION OF THE US. 00Z SAT SEP 29 MIAMI SOUNDING SHOWS EASTERLY FLOW UP TO 600 MB BRINGING PLENTY OF TROPICAL MOISTURE INTO SOUTH FLORIDA. ABOVE 600 MB THE FLOW BECOMES NORTHERLY, IN PART INFLUENCED BY THE AREA OF HIGH PRESSURE IN THE UPPER LEVELS OF THE ATMOSPHERE OVER THE SOUTH CENTRAL US. IN THE NEAR TERM A COLD FRONT EXTENDS FROM CENTRAL TEXAS INTO THE NE US. FOR SATURDAY THIS FRONT IS FORECAST TO STALL AND BEGIN TO GENERATE AN AREA OF LOW PRESSURE OVER SE TEXAS EXPECTED TO MOVE TOWARDS THE MOUTH OF THE MISSISSIPPI RIVER BY SUNDAY. THE UPPER LEVEL WINDS ARE FORECAST TO AMPLIFY ON MONDAY OVER THE CENTRAL AND SE US PRODUCING AN EXTENSIVE AREA OF SOUTHERLY WINDS OVER THE GULF OF MEXICO AND THE FLORIDA PENINSULA. THIS SOUTHERLY WINDS ARE EXPECTED TO INCREASE UP TO 25 KTS AT 850 MB WITH SURFACE WINDS UP TO 15 TO 20 KTS OVER THE ATLANTIC COASTAL WATERS POSSIBLE. GUSTY WINDS ARE ALSO EXPECTED OVER THE SOUTHERN AND EASTERN PORTIONS OF SOUTH FLORIDA, ESPECIALLY ON MONDAY. THE AREA OF LOW PRESSURE OVER THE SOUTH CENTRAL US LIFTS NORTHEASTWARD ON TUESDAY PUSHING A COLD FRONT OVER THE SE US. HOWEVER, THE FRONT IS NOT EXPECTED TO PUSH PAST THE CENTRAL PORTIONS OF THE FLORIDA PENINSULA. EASTERLY WINDS RETURN TO SOUTH FLORIDA ON WEDNESDAY, AS AN AREA OF HIGH PRESSURE BUILDS BACK IN THE WESTERN ATLANTIC AND INFLUENCES OUR WEATHER BETWEEN WEDNESDAY AND THE END OF THE FORECAST PERIOD. VERY LITTLE CHANGE IN TEMPERATURES IS EXPECTED FOR THE FORECAST PERIOD. HOWEVER, THE DEWPOINT TEMPERATURE IS EXPECTED TO INCREASE AFTER MONDAY AND TUESDAY WHICH WILL INCREASE THE LOW TEMPERATURES ESPECIALLY OVER THE EASTERN AND SOUTHERN SECTIONS OF SOUTH FLORIDA. THE COVERAGE OF THE PRECIPITATION FORECAST FOR SATURDAY AND SUNDAY IS FORECAST TO BE SLIGHTLY DIFFERENT. FOR SATURDAY MOST OF THE SHOWERS AND ISOLATED THUNDERSTORMS ARE FORECAST OVER THE INTERIOR SECTIONS, AS EAST AND WEST COAST SEA BREEZES PUSH INLAND. FOR SUNDAY, THERE COULD BE AN INCREASE IN SHOWERS OVER THE ATLANTIC WATERS BEGINNING SUNDAY MORNING WHICH IS EXPECTED TO SPREAD FROM THE SE TO THE INTERIOR AS THE DAY PROGRESSES. THE GREATEST CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS IS EXPECTED FOR MONDAY AND TUESDAY. FROM WEDNESDAY THROUGH THE END OF THE FORECAST PERIOD A MOIST EASTERLY FLOW WILL DOMINATE, WHICH IS EXPECTED TO CONCENTRATE SHOWERS AND ISOLATED STORMS IN THE INTERIOR DURING THE AFTERNOON AND EVENING, AND OVER THE ATLANTIC COASTAL WATERS DURING THE NIGHT AND EARLY MORNING HOURS. AVIATION...(ISSUED AT 125 AM EDT SAT SEP 29 2012). A FEW STRAY SHRA/POSSIBLE ISOLATED TSRA SLOWLY MOVING W THROUGH THE ATLC WATERS BUT NOTHING IN E COAST TAFS AT THIS TIME UNTIL THE E COAST SEA BREEZE GETS ESTABLISHED AND VCSH AFT 14Z. TSRA EXPECTED AFT 17Z WITH VCTS IN E COAST TAFS. ACTIVITY SHOULD BE TO THE W OF TERMINALS AND POSSIBLY TOO FAR INLAND TO AFFECT SITE BUT VCTS IN TAFS THROUGH 21Z. KTMB MOST VULNERABLE TO SEE A TSRA. AT KAPF...POSSIBLE MVFR VSBY IN BR FROM 09Z TO 12Z THEN AFT 20Z VCTS THROUGH 30/00Z. E COAST SURFACE WINDS CURRENTLY CALM TO NNW-N < 5 KNOTS BUT BECOMING EASTERLY TO NEAR 10 KNOTS AFT 14Z. AT KAPF...VCTS FROM 20Z TO 30/00Z. CURRENT SURFACE WIND CALM BECOMING AFT 13Z ESE < 5 KNOTS THEN SHIFTING W TO 10 KNOTS AFT 17Z AS W COAST SEA BREEZE DEVELOPS. MARINE...LIGHT EAST TO NORTHEAST WINDS ARE FORECAST FOR SATURDAY. FOR SUNDAY WINDS ARE FORECAST TO SHIFT FROM EASTERLY TO SOUTHEASTERLY AS A TROUGH OF LOW PRESSURE AMPLIFIES OVER THE SE US. WINDS ARE EXPECTED TO SHIFT FROM THE SOUTH ON MONDAY AND INCREASE TO 15 TO 20 KTS OVER THE ATLANTIC COASTAL WATERS. BY WEDNESDAY WINDS OVER THE ATLANTIC WATERS ARE FORECAST TO DECREASE FROM SOUTH TO NORTH. WAVE HEIGHTS OF 2 TO 3 FEET ARE FORECAST FOR THE PALM BEACH COASTAL WATERS FOR THE MONDAY-TUESDAY TIME FRAME. SEAS ARE ALSO EXPECTED TO INCREASE TO ABOUT 4 FEET ACROSS THE OUTER GULF ZONES BY TUESDAY. FIRE WEATHER... NO FIRE WEATHER CONCERNS. THE LOWEST AFTERNOON RH VALUES FOR THE ENTIRE FORECAST PERIOD ARE EXPECTED TO OCCUR ON SATURDAY. HOWEVER, THE VALUES ARE EXPECTED TO BE ABOVE 45 PERCENT. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 77 88 77 / 20 20 40 40 FORT LAUDERDALE 88 77 88 79 / 20 20 40 40 MIAMI 89 77 89 78 / 20 20 50 40 NAPLES 89 75 89 77 / 20 20 40 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS COLUMBIA SC
1000 AM EDT SAT SEP 29 2012 .SYNOPSIS... WEAK HIGH PRESSURE ACROSS THE AREA WILL CONTINUE TO WEAKEN AND SLIDE FARTHER TO THE SOUTH/SOUTHEAST. THIS WILL ALLOW A COLD FRONT TO MOVE SLOWLY ACROSS THE REGION TODAY. A LOW PRESSURE SYSTEM OVER TEXAS WILL MOVE NORTHEAST...SPREADING RAIN OVER THE AREA FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... A COLD FRONT WAS NORTH OF THE MIDLANDS THIS MORNING. A BAND OF SHOWERS WITH A FEW THUNDERSTORMS WAS LOCATED IN THE NORTH PART OF THE FORECAST AREA MOVING EAST WITH THE UPPER ZONAL FLOW. BOTH NAM AND RUC MODELS SHOW UPPER LOW NORTH AND A WEAK SHORT WAVE WITH ROUNDS THIS FEATURE THIS AFTERNOON. THIS IS EXPECTED TO HELP TO PULL THE COLD FRONT SOUTHWARD INTO THE REGION LATE THIS AFTERNOON OR EARLY THIS EVENING. INCREASED POPS TO 40-50 PERCENT SOUTH AND 60-80 PERCENT NORTH. OTHERWISE...EXPECT MODERATE INSTABILITY AHEAD OF THE FRONT WITH PWAT INCREASING TO ABOUT 1.80 INCHES. COULD SEE A ANOTHER WEAK SHORT WAVE MOVE THROUGH TONIGHT IN CYCLONIC FLOW ALOFT AS AN UPPER LOW SPINS OVER THE GREAT LAKES REGION. KEPT POP AT 30 TO 40 PERCENT THROUGH TONIGHT. WENT WITH CONSENSUS FOR HIGHS IN THE LOW TO MID 80S UNDER MOSTLY CLOUDY SKIES. MODELS PUSH THE COLD FRONT SOUTH OF THE CSRA OVERNIGHT WITH POPS DECREASING. SHOULD SEE OVERNIGHT LOWS IN THE LOW TO MID 60S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... THE COLD FRONT SHOULD BE SOUTH OF THE AREA SUNDAY MORNING. MODELS SHOWING AN INCREASE IN MOISTURE SUNDAY AFTERNOON AS A FRONT PUSHES BACK NORTH. LOW PRESSURE IS EXPECTED MOVE NORTHWARD ALONG THE FRONT FROM THE LOWER MS RIVER VALLEY TO THE TN VALLEY MONDAY NIGHT. WHILE THE GFS IS FASTER IN SPREADING ISENTROPIC LIFT NORTHWARD...ALL MODELS INDICATE AN INCREASE IN MOISTURE FLUX SUNDAY NIGHT THROUGH MONDAY. WILL KEEP HIGH CHANCE TO LIKELY POPS SUNDAY NIGHT INTO MONDAY NIGHT. CLOUDS AND PRECIP EXPECTED TO HOLD DAYTIME HIGHS IN THE MID 70S TO LOWER 80S. NIGHT-TIME LOWS IN THE 60S. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE MEDIUM RANGE MODELS HAVE THE LOW PRESSURE SYSTEM LIFTING NORTH OF THE AREA TUESDAY. AN UPPER LEVEL LOW WILL LINGER JUST WEST OF THE AREA THROUGH MID-WEEK BEFORE OPENING UP AND LIFTING NORTHEAST THURSDAY. KEPT CHANCE POPS FOR TUESDAY THROUGH WEDNESDAY NIGHT. MAY BEGIN TO FINALLY SEE SOME DRYING AGAIN AS WE MOVE INTO THURSDAY AS THE MAIN UPPER TROUGH GETS NEAR ENOUGH TO PUSH THE SURFACE FRONT AND ITS ASSOCIATED MOISTURE OFF THE COAST. AS FOR TEMP...CONTINUED WITH A BLEND OF MODEL GUIDANCE WHICH GENERALLY KEEPS READINGS A FEW DEGREES BELOW CLIMATOLOGY. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... MIXED CONDITIONS POSSIBLE THROUGH THE TAF PERIOD. FRONTAL BOUNDARY CONTINUES TO APPROACH THE AREA WITH WSR-88D RETURNS SHOWING SHOWERS MOVING THROUGH THE UPSTATE INTO THE NORTHERN MIDLANDS. MAIN CONCERN IS RAIN POTENTIAL THROUGH THE AFTERNOON...AND WITH CONFIDENCE REMAINING LOW HAVE INCLUDED VCSH FOR ALL TAF SITES FROM 15Z-16Z THROUGH 30/00Z. WV LOOP MID/UPPER FLOW TO BE MORE WEST/WEST NORTHWEST ACROSS THE AREA...THIS WILL LIKELY PRODUCE A SLOW MOVEMENT SOUTHWARD IN THE PRECIPITATION FIELD. EXPECT THE BEST CHANCE OF RAIN IN CAE/CUB...HOWEVER CONFIDENCE IN TIMING REMAINS TOO LOW TO INCLUDE IN TAFS. EXPECT MUCH OF THE RAIN TO DIMINISH WITH SUNSET AND FOG CHANCE WILL BE LOWER TONIGHT AS CLOUD COVER WILL PERSIST OVER THE AREA. EXTENDED AVIATION OUTLOOK...CHANCE OF PRECIPITATION AND ASSOCIATED RESTRICTIONS THROUGH MID WEEK...WITH LOWER CIGS EXPECTED LATE NIGHT/EARLY MORNING. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 07
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
913 AM EDT SAT SEP 29 2012 .SYNOPSIS... WEAK HIGH PRESSURE ACROSS THE AREA HIGH PRESSURE WILL CONTINUE TO WEAKEN AND SLIDE FARTHER TO THE SOUTH/SOUTHEAST. THIS WILL ALLOW A COLD FRONT TO MOVE SLOWLY ACROSS THE REGION TODAY. A LOW PRESSURE SYSTEM OVER TEXAS WILL MOVE NORTHEAST...SPREADING RAIN OVER THE AREA FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... A COLD FRONT WAS NORTH OF THE MIDLANDS THIS MORNING. A BAND OF SHOWERS WITH A FEW THUNDERSTORMS WAS LOCATED IN THE NORTH PART OF THE FORECAST AREA MOVING EAST WITH THE UPPER ZONAL FLOW. BOTH NAM AND RUC MODELS SHOW UPPER LOW NORTH AND A WEAK SHORT WAVE WITH ROUNDS THIS FEATURE THIS AFTERNOON. THIS IS EXPECTED TO HELP TO PULL THE COLD FRONT SOUTHWARD INTO THE REGION LATE THIS AFTERNOON OR EARLY THIS EVENING. INCREASED POPS TO 40-50 PERCENT SOUTH AND 60-80 PERCENT NORTH. OTHERWISE...EXPECT MODERATE INSTABILITY AHEAD OF THE FRONT WITH PWAT INCREASING TO ABOUT 1.80 INCHES. COULD SEE A ANOTHER WEAK SHORT WAVE MOVE THROUGH TONIGHT IN CYCLONIC FLOW ALOFT AS AN UPPER LOW SPINS OVER THE GREAT LAKES REGION. KEPT POP AT 30 TO 40 PERCENT THROUGH TONIGHT. WENT WITH CONSENSUS FOR HIGHS IN THE LOW TO MID 80S UNDER MOSTLY CLOUDY SKIES. MODELS PUSH THE COLD FRONT SOUTH OF THE CSRA OVERNIGHT WITH POPS DECREASING. SHOULD SEE OVERNIGHT LOWS IN THE LOW TO MID 60S. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... THE COLD FRONT SHOULD BE SOUTH OF THE AREA SUNDAY MORNING. MODELS SHOWING AN INCREASE IN MOISTURE SUNDAY AFTERNOON AS A FRONT PUSHES BACK NORTH. LOW PRESSURE IS EXPECTED MOVE NORTHWARD ALONG THE FRONT FROM THE LOWER MS RIVER VALLEY TO THE TN VALLEY MONDAY NIGHT. WHILE THE GFS IS FASTER IN SPREADING ISENTROPIC LIFT NORTHWARD...ALL MODELS INDICATE AN INCREASE IN MOISTURE FLUX SUNDAY NIGHT THROUGH MONDAY. WILL KEEP HIGH CHANCE TO LIKELY POPS SUNDAY NIGHT INTO MONDAY NIGHT. CLOUDS AND PRECIP EXPECTED TO HOLD DAYTIME HIGHS IN THE MID 70S TO LOWER 80S. NIGHT-TIME LOWS IN THE 60S. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE MEDIUM RANGE MODELS HAVE THE LOW PRESSURE SYSTEM LIFTING NORTH OF THE AREA TUESDAY. AN UPPER LEVEL LOW WILL LINGER JUST WEST OF THE AREA THROUGH MID-WEEK BEFORE OPENING UP AND LIFTING NORTHEAST THURSDAY. KEPT CHANCE POPS FOR TUESDAY THROUGH WEDNESDAY NIGHT. MAY BEGIN TO FINALLY SEE SOME DRYING AGAIN AS WE MOVE INTO THURSDAY AS THE MAIN UPPER TROUGH GETS NEAR ENOUGH TO PUSH THE SURFACE FRONT AND ITS ASSOCIATED MOISTURE OFF THE COAST. AS FOR TEMP...CONTINUED WITH A BLEND OF MODEL GUIDANCE WHICH GENERALLY KEEPS READINGS A FEW DEGREES BELOW CLIMATOLOGY. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... MIXED CONDITIONS POSSIBLE THROUGH THE TAF PERIOD. FRONTAL BOUNDARY CONTINUES TO APPROACH THE AREA WITH WSR-88D RETURNS SHOWING SHOWERS MOVING THROUGH THE UPSTATE INTO THE NORTHERN MIDLANDS. MAIN CONCERN IS RAIN POTENTIAL THROUGH THE AFTERNOON...AND WITH CONFIDENCE REMAINING LOW HAVE INCLUDED VCSH FOR ALL TAF SITES FROM 15Z-16Z THROUGH 30/00Z. WV LOOP MID/UPPER FLOW TO BE MORE WEST/WEST NORTHWEST ACROSS THE AREA...THIS WILL LIKELY PRODUCE A SLOW MOVEMENT SOUTHWARD IN THE PRECIPITATION FIELD. EXPECT THE BEST CHANCE OF RAIN IN CAE/CUB...HOWEVER CONFIDENCE IN TIMING REMAINS TOO LOW TO INCLUDE IN TAFS. EXPECT MUCH OF THE RAIN TO DIMINISH WITH SUNSET AND FOG CHANCE WILL BE LOWER TONIGHT AS CLOUD COVER WILL PERSIST OVER THE AREA. EXTENDED AVIATION OUTLOOK...CHANCE OF PRECIPITATION AND ASSOCIATED RESTRICTIONS THROUGH MID WEEK...WITH LOWER CIGS EXPECTED LATE NIGHT/EARLY MORNING. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$ 07
AREA FORECAST DISCUSSION
NWS BUFFALO NY
946 AM EDT SAT SEP 29 2012 .SYNOPSIS... MOST AREAS WILL REMAIN DRY TODAY WITH VARYING AMOUNTS OF CLOUD COVER. THERE IS JUST A SMALL CHANCE OF AN ISOLATED SHOWER THIS AFTERNOON ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND ALSO EAST OF LAKE ONTARIO. A POTENT UPPER LEVEL LOW WILL DROP SOUTH INTO THE REGION TONIGHT WITH INCREASING RAIN CHANCES ESPECIALLY ACROSS WESTERN NY. INTERMITTENT SHOWERS WILL CONTINUE SUNDAY AND SUNDAY NIGHT AS THIS SYSTEM MOVES SLOWLY EAST ACROSS THE AREA. SHOWERS WILL LINGER EAST OF LAKE ONTARIO INTO MONDAY WHILE THE REST OF THE REGION DRIES OUT AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES. && .NEAR TERM /THROUGH TONIGHT/... THROUGH MID-MORNING...SHOWERS EAST OF LAKE ONTARIO HAVE DIMINISHED. RADAR DID PICK UP AN ISOLATED SHOWERS ALONG THE MONROE/WAYNE COUNTY BORDER WHICH DEVELOPED ALONG A CONVERGENCE OF BOUNDARIES. THIS SHOULD BE FAIRLY SHORT LIVED...GIVEN THE TEMPORARY NATURE OF THE SUBTLE CONVERGING FEATURES. OTHERWISE...VISIBLE SATELLITE SHOWED LOW CLOUDS AND FOG IN NORTHERN JEFFERSON COUNTY...LIKELY ENHANCED BY AN UPSLOPE NORTHEAST FLOW. THIS AREA SHOULD ALSO DISSIPATE THROUGH THIS MORNING WITH DAYTIME HEATING. FOR THE REST OF TODAY...A MID LEVEL CLOSED LOW DEVELOPING OVER NORTHERN QUEBEC WILL DROP QUICKLY SSW AND REACH GEORGIAN BAY BY THIS EVENING. MEANWHILE THE WEAK SURFACE LOW ALONG THE SOUTHERN NEW ENGLAND COAST EARLY THIS MORNING WILL BECOME CAPTURED BY THE BROADENING CIRCULATION OF THE CLOSED LOW...AND WILL MOVE NORTHWARD ALONG THE MAINE COAST. THE WESTERN EDGE OF DEEPER MOISTURE AND MID LEVEL DEFORMATION ASSOCIATED WITH THIS COASTAL LOW WILL REMAIN ACROSS THE ADIRONDACKS AND SAINT LAWRENCE VALLEY TODAY. THIS MAY STAY JUST CLOSE ENOUGH TO SUPPORT A FEW MORE ISOLATED SHOWERS ACROSS PORTIONS OF LEWIS AND NORTHEAST JEFFERSON COUNTY. THERE MAY ALSO BE AN ISOLATED SHOWER OR TWO ACROSS THE HIGHER TERRAIN OF THE WESTERN SOUTHERN TIER AND FINGER LAKES THIS AFTERNOON IN RESPONSE TO VERY LIMITED DIURNAL INSTABILITY AND NORTHERLY UPSLOPE FLOW. FINALLY...THE HRRR SUGGESTS A WEAK SW LAKE BREEZE WILL DEVELOP ON LAKE ERIE...WHICH IF IT DEVELOPS COULD CAUSE A FEW ISOLATED SHOWERS MAY DEVELOP IN THE NIAGARA ESCARPMENT. IN ALL OF THESE CASES...THE CAUSE FOR SHOWERS IS QUITE SUBTLE...AND ANY ACTIVITY SHOULD BE ISOLATED IN NATURE. 850MB TEMPS OF AROUND +4C WILL SUPPORT HIGHS IN THE LOWER TO MID 60S ACROSS LOWER ELEVATIONS...AND UPPER 50S ACROSS HIGHER TERRAIN WHERE CLOUD COVER SHOULD BE THICKER AND MORE PERSISTENT. TONIGHT...THE MID LEVEL LOW WILL CONTINUE SSW ACROSS LAKE HURON THEN BEGIN TO PIVOT EAST ACROSS WESTERN NY/PA BY EARLY SUNDAY MORNING. INCREASING DPVA IN ADVANCE OF THIS STRONG MID LEVEL CLOSED LOW WILL BRING INCREASING CHANCES OF A FEW SHOWERS OVERNIGHT ACROSS WESTERN NY...AND ALSO ACROSS THE EASTERN LAKE ONTARIO REGION. THE LOWEST RAIN CHANCES OVERNIGHT WILL BE ACROSS THE FINGER LAKES AND CENTRAL NY WHERE DEEPER MOISTURE AND ASCENT IS SLOW TO ARRIVE. THE NAM...CANADIAN GEM AND SEVERAL VERSIONS OF OUR LOCALLY RUN WORKSTATION WRF SUGGEST SOME LAKE EFFECT RAIN MAY DEVELOP OVERNIGHT OVER BOTH LAKES ERIE AND ONTARIO IN WEAK EASTERLY FLOW. TEMPS ALOFT WILL COOL WITH THE APPROACH OF THE UPPER LOW...AND THIS WILL SUPPORT LAKE INDUCED EQUILIBRIUM LEVELS OF AROUND 25K FEET. THE VERY WEAK AND SOMEWHAT SHEARED FLOW WILL KEEP WHAT FORMS DISORGANIZED... ALTHOUGH IT MAY BE QUITE CONVECTIVE GIVEN THE HIGH EQUILIBRIUM LEVELS WITH EVEN SOME THUNDER POSSIBLE. THE MEAN EASTERLY BOUNDARY LAYER FLOW WILL KEEP MUCH OF THIS ACTIVITY OVER THE LAKES...BUT SOME MAY BEGIN TO BRUSH THE LAKE ONTARIO SHORELINE FROM THE BRADDOCK BAY/HAMLIN AREA OF MONROE COUNTY WEST ACROSS ORLEANS AND NIAGARA COUNTIES LATE TONIGHT. HAVE INDICATED THE HIGHEST RAIN CHANCES AND RAIN AMOUNTS IN THAT AREA OVERNIGHT. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... A COOL AND DAMP DAY IS EXPECTED ON SUNDAY TO CLOSE OUT THE WEEKEND. FORECAST MODELS ARE IN GOOD AGREEMENT OF PLACING A CUT-OFF LOW OF COLD AIR ALOFT DIRECTLY OVERHEAD OF WESTERN NEW YORK SUNDAY MORNING. THE 00Z GFS BUFKIT PROFILE FOR KBUF SHOWS A STEADY MOIST ADIABATIC TEMPERATURE LAPSE RATE FROM THE SURFACE RIGHT THROUGH AROUND 400 MB AT 15Z SUNDAY. THIS WILL PROVIDE SUFFICIENT SYNOPTIC INSTABILITY FOR RAIN SHOWERS WHICH SHOULD BE ONGOING AT THE START OF THE SHORT TERM PERIOD. IF THIS WERE TROPICALLY SOURCED AIR THIS SETUP WOULD MAKE FOR VERY HEAVY RAIN ACROSS THE FORECAST AREA SUNDAY...BUT THIS IS NOT THE CASE. THE SOURCE REGION OF THE AIRMASS ALOFT IS CONTINENTAL POLAR AND IS HAS LIMITED MOISTURE. PRECIPITABLE WATER VALUES WILL ONLY BE AROUND 0.75 INCHES. THIS IS ABOUT NORMAL FOR LATE SEPTEMBER WITH A NEUTRAL ANOMALY SO NO HEAVY RAIN WILL BE FORECAST. QPF SUNDAY WILL ONLY RANGE BETWEEN 0.10 AND 0.25 INCH IN LIGHT SHOWERS. TEMPERATURES WILL NOT CLIMB MUCH WITH OVERCAST SKIES AND PRECIP AROUND MUCH OF THE DAY. WITH COOL AIR ALOFT...AND 850 MB TEMPS OF ONLY AROUND +4C HIGHS WILL ONLY REACH INTO THE MID 50S ACROSS THE SOUTHERN TIER TO AROUND 60 EAST OF LAKE ONTARIO NORTH OF THE TRACK OF THE UPPER LOW. ADDITIONALLY...DESPITE SIGNIFICANT LAKE INDUCED INSTABILITY...THE PATTERN DURING THE DAY SUNDAY IS NOT FAVORABLE FOR ANY LAKE EFFECT PRECIPITATION GIVEN THE WEAK FLOW OVER THE LAKES. WINDS IN THE LOWER HALF OF THE ATMOSPHERE WILL BE LESS THAN 10 KNOTS WHICH WILL NOT ALLOW ANY ORGANIZED BANDS TO FORM. BY SUNDAY NIGHT A DISTURBANCE ROUNDING THE WESTERN SIDE OF THE UPPER LOW WILL ACT TO KICK THE SYSTEM TO THE NORTHEAST UP THROUGH NEW ENGLAND AND OVER THE MOUTH OF THE SAINT LAWRENCE RIVER. RAIN SHOWERS WILL TAPER OFF QUICKLY SUNDAY EVENING AS THE MOISTURE EXITS THE FORECAST AREA WITH THE UPPER LOW. AT THIS POINT THE POSITION OF THE THE UPPER LOW TO THE NORTHEAST WILL BRING AN INCREASED WIND FLOW AND FETCH ACROSS LAKE ONTARIO. THIS WEST TO NORTHWEST FLOW WILL ALLOW FOR AN EXTENDED CHANCE OF RAINFALL IN THE FORM OF LAKE EFFECT ON SUNDAY NIGHT EAST OF LAKE ONTARIO WHILE WESTERN NEW YORK BEGINS TO DRY OUT. LOW TEMPS...ESPECIALLY IN AREAS WHERE SKIES CLEAR...WILL FALL INTO THE MIDDLE TO UPPER 40S. SOME PATCHY FOG IS POSSIBLE ACROSS THE SOUTHERN TIER AS THEY ARE EXPECTED TO CLEAR OUT BEFORE OTHER PARTS OF WNY. ON MONDAY THE UPPER LOW WILL LIFT FURTHER NORTHEAST INTO THE CANADIAN MARITIMES AND SOME UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE WILL BRING FAIR WEATHER WITH A RETURN OF SOME SUNSHINE. HIGHS WILL BE A BIT WARMER WITH WINDS ADVECTING OUT OF THE SOUTHEAST. HIGHS SHOULD CLIMB INTO THE 60S WITH 850 MB TEMPS WARMING TO NEAR +8C. FURTHER UPSTREAM...IN THIS CASE ACROSS THE NORTHERN GULF COAST...A MOIST SURFACE LOW WILL BE FORMING WITH +2 SD PRECIPITABLE WATER VALUES. MONDAY NIGHT BRINGS AN RETURN OF CLOUDS AS WARM ADVECTION SETS UP AHEAD OF THE NEXT STORM SYSTEM APPROACHING FROM THE NORTHERN GULF. 850MB TEMPS WILL RISE TO +10 TO +12C OVERNIGHT AND SURFACE TEMPS MAY ACTUALLY RISE FOR A TIME DURING THE NIGHT. MILD LOWS WILL RUN IN THE LOW TO MID 50S. A CHANCE OF SHOWERS WILL ALSO DEVELOP AS A SURFACE WARM FRONT ASSOCIATED WITH THE LOW LIFTS ACROSS THE CENTRAL APPALACHIANS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A PERIOD OF WARMER THAN NORMAL TEMPS WITH SOME LATE SEPTEMBER CONVECTION IS POSSIBLE LATER NEXT WEEK. A DEEP TROUGH OVER THE CENTRAL US WILL LIFT NORTHEAST TUESDAY INTO WEDNESDAY. AHEAD OF THE TROUGH A GULF LOW WILL BRING AN INCREASE IN MOISTURE ACROSS NEW YORK UNDER A FULL CONUS LATITUDE SOUTHERLY FLOW. THIS KEEPS A CHANCE FOR RAIN SHOWERS IN THE FORECAST FOR TUESDAY. CONVECTIVE PARAMETERS ARE NEAR ZERO ACROSS THE FORECAST AREA WITH WARM AIR INCREASING ALOFT. THE RAIN WILL MAINLY BE WARM FRONTAL. THIS COULD BRING UPWARDS OF A HALF INCH OR MORE OF RAIN. HIGHS WILL REACH INTO THE UPPER 60S TO NEAR 70. ON WEDNESDAY A CHANCE FOR THUNDERSTORMS DEVELOPS AS THE UPPER LEVEL TROUGH DIGGING NORTHEAST FROM THE GULF COAST BRINGS COOL AIR ALOFT DESTABILIZING THE ATMOSPHERE. THE THUNDERSTORMS COULD FORM ALONG A COLD FRONT ASSOCIATED WITH THE SURFACE LOW LIFTING NORTH INTO CANADA. TEMPS WARM EVEN MORE WITH MOST SPOTS GETTING UPPER 60S TO EVEN SOME MID 70S ACROSS CENTRAL NY. RIDGING BEHIND THE TROUGH SHOULD BRING FAIR WEATHER FOR THURSDAY AND ANOTHER DAY OF WARM TEMPS. THEN ON FRIDAY THE 00Z GFS AND ECMWF BOTH SHOW A LARGE TROUGH DIGGING ACROSS THE WEST COAST WITH A COLD FRONT POSSIBLY BRINGING ANOTHER SHOT AT THUNDERSTORMS ON FRIDAY. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... PATCHY FOG WITH LOCAL IFR ACROSS THE SOUTHERN TIER WILL BURN OFF IN THE NEXT HOUR OR TWO...WITH VFR PREVAILING THEREAFTER. AREAS OF MID LEVEL CLOUD IN THE 4-8K FOOT RANGE ACROSS CENTRAL NY WILL DRIFT EAST THIS MORNING AND THEN TEND TO REDEVELOP FARTHER WEST THIS AFTERNOON. PERIODS OF CIRRUS WILL ALSO CROSS THE REGION TODAY. TONIGHT AN UPPER LEVEL LOW WILL DROP SOUTH ACROSS THE GREAT LAKES. THIS WILL BRING INCREASING AND LOWERING CLOUD COVER ALONG WITH AN INCREASING CHANCE OF SHOWERS ACROSS WESTERN NY OVERNIGHT. INITIALLY THE LOW LEVELS SHOULD REMAIN UNSATURATED WITH MAINLY VFR VSBY AND CIGS...EXCEPT FOR THE SOUTHERN TIER WHERE MVFR IS MORE LIKELY. OUTLOOK... SUNDAY...MVFR/IFR WITH INTERMITTENT SHOWERS. MONDAY...MAINLY VFR. TUESDAY AND WEDNESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS. && .MARINE... AN UPPER LEVEL LOW WILL DROP SOUTH OUT OF CANADA LATER TODAY THROUGH SUNDAY. A FEW PERIODS OF NORTH TO NORTHEAST WINDS IN THE 10-15 KNOT RANGE WILL BRING CHOPPY WAVES TO THE SOUTH SHORE OF LAKE ONTARIO AT TIMES...BUT CONDITIONS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. A SURFACE LOW WILL DEEPEN OVER NEW ENGLAND LATER SUNDAY NIGHT AND MONDAY AND BRING INCREASING WESTERLY WINDS TO LAKE ONTARIO. THIS WILL LIKELY BRING A PERIOD OF SMALL CRAFT ADVISORY CONDITIONS FROM LATER SUNDAY NIGHT THROUGH MONDAY...ESPECIALLY ON THE EAST HALF. COLD AIR ALOFT AND SOME CONVECTIVE SHOWERS WILL BRING THE POTENTIAL FOR WATERSPOUTS LATER TONIGHT INTO SUNDAY MORNING ON BOTH LAKES ERIE AND ONTARIO. WATERSPOUTS ARE MOST COMMON IN AND NEAR BANDS OF CLOUDS LAKE EFFECT CLOUDS AND SHOWERS WHERE LOW LEVEL CONVERGENCE IS LOCALLY MAXIMIZED. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...HITCHCOCK NEAR TERM...AR/APFFEL/HITCHCOCK SHORT TERM...SMITH LONG TERM...SMITH AVIATION...HITCHCOCK MARINE...HITCHCOCK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
648 AM EDT SAT SEP 29 2012 .SYNOPSIS... THE CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE ON THE INCREASE THIS WEEKEND AS A COLD FRONT STALLS ACROSS THE EASTERN CAROLINAS. NEXT WEEK WILL REMAIN UNSETTLED AS LOW PRESSURE DEVELOPS ALONG THE GULF COAST AND MOVES ACROSS THE WESTERN CAROLINAS. A COLD FRONT WILL CROSS THE AREA BY LATE WEEK BRINGING DRIER AND COOLER WEATHER. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM SATURDAY...NO SIGNIFICANT CHANGES TO THE GOING FORECAST. CURRENTLY THE BULK OF CONVECTIVE ACTIVITY ACROSS THE CAROLINAS REMAINS ACROSS THE NORTHERN TIER OF NC...NORTHEAST OF THE CENTERLINE OF THE APPROACHING 300 MB JET STREAK. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... A SIGNIFICANT CHANGE IN THE WEATHER WILL BEGIN TODAY AS A COLD FRONT AND ITS ASSOCIATED UPPER LEVEL SYSTEM BEGIN TO AFFECT THE EASTERN CAROLINAS. THE FRONT CURRENTLY LIES STALLED ACROSS SOUTHERN NORTH CAROLINA FROM THE SOUTH SIDE OF CHARLOTTE TO SOUTHERN PINES TO ROCKY MOUNT. A WEAK SURFACE LOW WILL DEVELOP ALONG THE FRONT THIS AFTERNOON...AND AS THE LOW MOVES EAST AND OFFSHORE TONIGHT THE FRONT SHOULD GET DRAGGED OFFSHORE BY DAYBREAK SUNDAY. THE AIRMASS SOUTH OF THE FRONT IS MARITIME SUBTROPICAL IN NATURE WITH PRECIPITABLE WATER 1.5 TO 1.7 INCHES AND REASONABLY STEEP LAPSE RATES ALOFT. ALTHOUGH SUNSHINE SHOULD BE FILTERED BY PLENTY OF MID LEVEL CLOUDS (ESPECIALLY ACROSS NORTH CAROLINA) I STILL ANTICIPATE AFTERNOON HIGHS TO REACH THE LOWER TO MID 80S FOR MOST AREAS. WITH DEWPOINTS IN THE MID TO UPPER 60S THIS SHOULD GENERATE SBCAPE VALUES AS HIGH AS 1200 J/KG WITH LIFTED INDICES DOWN TO -4. A BELT OF STRONGER MID-LEVEL WINDS ASSOCIATED WITH A JET STREAK MOVING EAST ACROSS NORTH CAROLINA WILL GENERATE 0-6 KM BULK SHEAR VALUES AROUND 30 KT...SUFFICIENT FOR MULTICELL STORM ORGANIZATION. SEVERE WEATHER IN THE FORM OF STRONG WINDS AND MARGINALLY SEVERE HAIL CANNOT BE RULED OUT...MAINLY THIS AFTERNOON. INTERESTINGLY IT IS THE JET STREAK ITSELF THAT MAY SERVE TO REDUCE COVERAGE OF SHOWERS AND STORMS THIS AFTERNOON. UNTIL EARLY EVENING OUR FORECAST AREA WILL REMAIN WITHIN THE RIGHT-EXIT REGION OF THE JET STREAK...A REGION TYPIFIED BY UPPER-LEVEL CONVERGENCE AND INFERRED SINKING MOTION BENEATH. FOR THIS REASON MY FORECAST POPS ARE CLOSER TO THE DRIER GFS MOS NUMBERS FOR TODAY...AND FOCUS ON THE SEABREEZE AS A PREFERRED LIFTING MECHANISM. THIS EVENING THE JET STREAK WILL MOVE INTO EXTREME EASTERN NORTH CAROLINA PLACING MY SOUTHEASTERN NC COUNTIES AT LEAST BRIEFLY WITHIN THE RIGHT-ENTRANCE REGION OF THE UPPER JET STREAK...A MUCH MORE FAVORABLE ZONE FOR ENHANCED SYNOPTIC ASCENT. THIS EXPLAINS MY HIGHER POPS IN THE 8 PM TO MIDNIGHT TIME FRAME...ESPECIALLY AROUND WILMINGTON. THE SURFACE COLD FRONT SHOULD THEN SLIP IN FROM THE NORTHWEST AND MAKE IT OFFSHORE BY SUNRISE SUNDAY. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...COLD FRONT OFF THE COAST AT THE START OF THE PERIOD WILL STALL BEFORE MOVING BACK ONSHORE LATER SUN OR EARLY MON AS A WARM FRONT. THE EVOLUTION OF A SOUTHERN STREAM 5H TROUGH AND SURFACE LOW OVER SOUTHEAST TX WILL BE CRITICAL IN DETERMINING WHEN THE STALLED FRONT BEGINS TO MOVE. THE FRONT WILL BE LIFTED NORTH BY THE NORTHEAST MOVEMENT OF THE WESTERN GULF OF MEXICO SURFACE LOW SUN INTO MON. APPROACH AND PASSAGE OF WARM FRONT WILL BE ACCOMPANIED BY AN INCREASE IN PRECIP COVERAGE LATE SUN AND SUN NIGHT. WENT AHEAD AND BUMPED POP TO HIGH CHANCE LATE SUN. THE COMBINATION OF INCREASING CLOUD COVER AND SHOWERS/THUNDERSTORMS WILL KEEP HIGHS BELOW CLIMO SUN WHILE CLOUDS AND WEAK WARM ADVECTION WILL HOLD SUN NIGHT LOWS ABOVE CLIMO. FORECAST AREA WILL SOLIDLY BE IN THE WARM SECTOR MON/MON NIGHT WITH LOW LEVEL SOUTHEAST TO SOUTH FLOW VEERING WITH HEIGHT. COMBINATION OF DEEP MOISTURE...DIURNAL INSTABILITY AND DIVERGENCE ALOFT SHOULD PRODUCE PLENTY OF SHOWERS AND THUNDERSTORMS. ACTIVITY MAY WELL CONTINUE MON NIGHT WITH FORECAST SOUNDINGS SHOWING DEVELOPMENT OF STRONG LOW LEVEL JET. SOUTHERLY LOW WILL PUSH TEMPERATURES ABOVE CLIMO MON AND MON NIGHT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 3 AM SATURDAY...DEEP BROAD 5H TROUGH OVER THE MS VALLEY WILL BE SLOW TO LIFT NORTHEAST NEXT WEEK...ENSURING ACTIVE WEATHER FOR MUCH OF THE PERIOD. DEEP SOUTHERLY FLOW THROUGH THE MIDDLE OF NEXT WEEK ALONG WITH DIURNAL HEATING AND THE PRESENCE OF PASSING SHORTWAVES IN FLOW ALOFT WILL LEAD TO DIURNAL SHOWERS AND THUNDERSTORMS FOR THE FIRST HALF OF THE PERIOD. THE SECOND HALF OF THE PERIOD REMAINS IN QUESTION AS GUIDANCE CONTINUES TO SHOW VERY LITTLE IN THE WAY OF RUN TO RUN CONSISTENCY. THE ISSUE WILL BE HOW QUICKLY THE 5H TROUGH IS ACCELERATED NORTHEAST AND WHETHER THE MID LEVEL RIDGE DEVELOPING OVER THE WESTERN ATLANTIC IS STRONG ENOUGH TO BUILD WEST LATE IN THE PERIOD. GIVEN THE UNCERTAINTY ONLY PLAN MINIMAL CHANGES AT THIS TIME. TEMPERATURES WILL BE ABOVE CLIMO THROUGH THE PERIOD...BUT HOW MUCH ABOVE LATE DEPENDS ON HOW THE MID LEVEL PATTERN EVOLVES. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 12Z...CONVECTION NORTH OF THE REGION IS ASSOCIATED WITH A FRONTAL BOUNDARY ORIENTED WEST TO EAST ACROSS CENTRAL NORTH CAROLINA. MOST OF THIS CONVECTION WILL STAY NORTH OF THE REGION THROUGH THE MORNING HOURS. THE HRRR MODEL DOES BRING IN A BATCH OF CONVECTION TO OUR INLAND ZONES AROUND 19Z...REACHING THE COAST AROUND 21Z. THERE IS MODERATE UNCERTAINTY WITH RESPECT TO COVERAGE AND INTENSITY OF THE PRECIPITATION. THINK THE SHOWERS WILL NOT BE TOO HEAVY AT FIRST...AS SOLAR INSOLATION WILL BE WEAK TODAY. CONDITIONS SHOULD DETERIORATE THIS EVENING AS DEEP MOISTURE MOVES IN...IN RESPONSE TO THE DIVERGENT QUADRANT OF THE JET. IFR CEILINGS ARE POSSIBLE AFTER 06Z...BUT LOW CONFIDENCE ON THIS SCENARIO AT THIS TIME. EXTENDED OUTLOOK...POTENTIAL MORNING FOG/STRATUS SUNDAY MORNING MAY REDUCE CIGS/VSBYS TO IFR LEVELS. UNSETTLED WEATHER ASSOCIATED WITH A STALLED FRONTAL BOUNDARY COULD PRODUCE PERIODS OF TEMPO SUB-VFR CONDITIONS ACROSS THE AREA THROUGH WEDNESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM SATURDAY...LATEST WIND/WAVE OBSERVATIONS CLOSELY MATCH THE CURRENT FORECAST. NO CHANGES NEEDED. PREVIOUS DISCUSSION FROM 300 AM FOLLOWS... A COLD FRONT HAS NEARLY STALLED ACROSS INTERIOR SOUTHERN AND EASTERN NORTH CAROLINA. LITTLE MOTION OF THE FRONT IS EXPECTED THROUGH THIS AFTERNOON AS WEAK LOW PRESSURE IS EXPECTED TO DEVELOP NEAR CHARLOTTE. AS THE LOW MOVES EAST AND OFFSHORE THIS EVENING THE FRONT WILL ACCELERATE TO THE SOUTHEAST AND SHOULD BE TRAVERSING THE COASTAL WATERS AROUND DAYBREAK SUNDAY...WITH A WIND SHIFT FROM THE SOUTHWEST AROUND TO THE NORTH. WIND SPEEDS TODAY SHOULD AVERAGE AROUND 10 KNOTS...ALTHOUGH ANY THUNDERSTORMS THIS AFTERNOON OR THIS EVENING WILL HAVE THE CAPABILITY OF PRODUCING STRONGER...GUSTY WINDS. AS THE SURFACE LOW PUSHES OFF THE COAST NEAR CAPE LOOKOUT LATE THIS EVENING WE MAY SEE A PERIOD OF 15 KNOT SOUTHWESTERLY WINDS AHEAD OF THE COLD FRONT...ESPECIALLY IN THE CAPE FEAR AREA WATERS. SEAS ARE CURRENTLY AROUND 2 FEET WITH A DOMINANT PERIOD OF 8 TO 9 SECONDS IN EASTERLY SWELL. LITTLE CHANGE IS EXPECTED UNTIL THE FRONT PUSHES CLOSER TO THE AREA TONIGHT...AT WHICH POINT SOME 3-FOOT COMBINED SEAS MAY DEVELOP AWAY FROM SHORE. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...FRONT MOVING ACROSS THE WATERS EARLY SUN WILL STALL JUST EAST OF THE WATERS BEFORE RETURNING AS A WARM FRONT LATE SUN OR EARLY MON. OFFSHORE FLOW BEHIND THE FRONT WILL BE LIGHT WITH LIMIT COLD ADVECTION AND WEAK GRADIENT KEEPING SPEEDS CLOSE TO 10 KT. SOUTHERLY FLOW WILL DEVELOP AS THE FRONT LIFTS...BUT GRADIENT REMAINS WEAK AND SPEEDS WILL STAY IN THE 10 KT OR LESS RANGE. SEAS WILL BE 2 TO 3 FT THROUGH THE PERIOD. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 AM SATURDAY...GRADIENT BECOMES MORE DEFINED TUE WITH SOUTHERLY FLOW INCREASE TO CLOSE TO 15 KT BY AFTERNOON. SOUTHERLY FLOW BECOMES WESTERLY AND DECREASES EARLY WED AS WEAK COLD FRONT MOVES OFF THE COAST. FRONT SHIFTS WEST DURING WED WITH WESTERLY FLOW BACKING TO SOUTHERLY. LITTLE CHANGE TO THE GRADIENT IS EXPECTED AND SPEEDS REMAIN CLOSE TO 10 KT THROUGH THE DAY. SEAS WILL RUN 2 TO 4 FT TUE BUT DROP BACK TO 2 TO 3 FT FOR WED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...III LONG TERM...III AVIATION...43
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
941 AM EDT SAT SEP 29 2012 .SYNOPSIS... RIDGE ACROSS THE AREA TODAY WILL BEGIN TO WEAKEN. AN UPPER LEVEL DISTURBANCE OVER QUEBEC WILL MOVE SOUTH TODAY AND WILL AFFECT THE AREA LATE TONIGHT AND SUNDAY. HIGH PRESSURE WILL MOVE IN FOR SUNDAY NIGHT AND PART OF MONDAY BEFORE MOVING NORTH AS LOW PRESSURE FROM THE GULF OF MEXICO HEADS INTO THE AREA. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... WEAK LAZY TROUGH WILL MOVE SOUTH ACROSS THE AREA AND IS RESPONSIBLE FOR MUCH OF THE CLOUD COVER OVER THE FORECAST AREA THIS MORNING. A BIT OF CONVECTIVE CLOUD ACTIVITY WAS PRESENT OVER MICHIGAN AT THIS TIME AND THIS WILL SLIDE SOUTH ACROSS THE AREA. SO FAR...NO PRECIPITATION WAS ASSOCIATED WITH THIS FEATURE BUT MY CONCERN IS THAT THERE MAY BE SOME LAKE ENHANCEMENT WITH THE ACTIVITY FOR THIS AFTERNOON. LATEST HRRR MODEL SUGGESTS SOME PRECIPITATION OVER NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA THIS AFTERNOON AWAY FROM THE LAKE FROM THIS FEATURE. WILL KEEP FORECAST DRY FOR THE TIME BEING AND MONITOR FOR POSSIBLE ADDITION OF SHOWERS FOR THIS AFTERNOON AND EVENING. REST OF THE AREA SHOULD REMAIN DRY THROUGH THE DAY. MADE SOME MINOR ADJUSTMENTS TO HOURLY TEMPERATURES BUT MAX TEMPERATURES APPEAR TO BE ON TARGET AT THIS TIME. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... THE FORECAST IS NOT CLEAR CUT FOR ANY PERIOD. AN UPPER LOW OVER QUEBEC WILL BE MOVING SOUTH TODAY AND WILL AFFECT THE FORECAST AREA FOR TONIGHT INTO SUNDAY. THIS RUN OF THE MODELS ARE MUCH DRIER WITH THIS FEATURE. KEPT CLOSE TO THE PREVIOUS FORECAST. JUST WENT CHANCE POPS TONIGHT AND THEN LIKELY SUNDAY OVER NE OH AND NW PA. A BIG QUESTION IS HOW FAR WEST WILL THE THREAT BE. TOLEDO TO FINDLAY IS ON THE EDGE. BUT WITH THE CIRCULATION AROUND THE LOW CAN`T RULE OUT SOME LIGHT SHOWERS FOR THAT AREA. CONTINUED WITH WATERSPOUTS ON THE LAKE SUNDAY AND ADDED THUNDER TO THE LAKE AND NE OH AND NW PA BASED ON THE LAKE AND 500 MB TEMPERATURE DIFFERENCE BEING NEAR 43C. SMALL HAIL IS ALSO POSSIBLE...NOT INCLUDED IN THE ZONES/GRIDS YET. AS THE UPPER LOW MOVES EAST SUNDAY NIGHT THE THREAT OF SHOWERS WILL DECREASE FROM WEST TO EAST. HIGH PRESSURE WILL BUILD IN LATE SUNDAY NIGHT AND THEN BEGIN MOVING NORTH SUNDAY AS LOW PRESSURE HEADS TOWARDS THE FORECAST AREA FOR MONDAY NIGHT. THIS IS A MODEL CHANGE SO NOT GOING TO WILD IN BRINGING IN THE SHOWERS TOO QUICKLY...BUT THE TIMING MAY NEED TO BE ADJUSTED. IT IS POSSIBLE THAT SOME SHOWERS COULD MAKE IT INTO THE SOUTHERN PORTION OF THE FORECAST AREA LATE MONDAY AFTERNOON. THE UPPER TROF ASSOCIATED WITH THIS SURFACE LOW WILL BE OVER THE REGION INTO MID WEEK. THE MODELS HANDLE IT DIFFERENTLY...THE ECMWF HAS A CLOSED LOW. ON THE EDGE ABOUT THAT...ITS HISTORY THE LAST FEW WEEKS HAS NOT BEEN REAL GOOD WITH CLOSED LOWS. NONE THE LESS A THREAT OF SHOWERS WILL EXIST...LIKELY POPS MAY EVEN BE NEEDED. USED A BLEND OF GUIDANCE FOR THE TEMPERATURES AS THE FORECAST IS TRICKY WITH ALL THE MODEL DIFFERENCES. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... WEDNESDAY THE GFS AND ECMWF ARE OUT OF SYNC. GFS HAS STRONG LOW PRESSURE SYSTEM OVER LAKE ERIE...WHILE ECMWF HAS A RIDGE OF HIGH PRESSURE OVER THE EASTERN LAKES. FOR NOW WILL CONTINUE WITH THE HPC SOLUTION...WHICH IS THE ECMWF. BOTH MODELS HAVE WEAK RIDGE OVER THE AREA THURSDAY SO WILL REMOVE ALL MENTION OF PRECIP. TREND FOR THE TWO MODELS IS SIMILAR FOR THE END OF THE WORK WEEK WITH A LOW PRESSURE SYSTEM MOVING ACROSS THE LAKES DRAGGING A COLD FRONT ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY MORNING. GFS IS FASTER OF THE TWO MODELS...FOR NOW WILL GO WITH THE TIMING OF THE ECMWF WHICH HAS THE FRONT INTO NW OH BY 12Z FRIDAY AND EAST OF THE AREA BY LATER AFTERNOON. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS WILL CONTINUE SATURDAY. CLOUDS WILL THICKEN AND LOWER THROUGH THE DAY AS UPPER LEVEL TROUGH SWINGS ACROSS THE AREA. LIGHT S-SW WINDS NEAR LAKESHORE WILL BECOME ONSHORE THIS AFTERNOON. SURFACE TROUGH WILL SWING ACROSS EASTERN LAKES SUNDAY...WHICH SHOULD BRING SOME SHOWERS TO EASTERN HALF OF THE FORECAST AREA. WILL SEE RAIN SUNDAY BUT CONFIDENCE IS LOW AS TO HOW MUCH. MODEL RUNS TODAY HAVE BEEN MUCH DRIER THAN PREVIOUS 2 DAYS. .OUTLOOK...NON-VFR PROBABLE SUNDAY AND AGAIN ON TUESDAY IN SHRA. && .MARINE... HIGH PRESSURE WILL REMAIN OVER THE LAKE THROUGH SATURDAY. GRADIENT SHOULD BE WEAK ENOUGH FOR EXPECT LAKE/LAND BREEZES TO DEVELOP BOTH TODAY AND SATURDAY. WEAK TROUGH/LOW MOVES ACROSS THE LAKE SUNDAY BUT CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. WITH WINDS GENERALLY 10 KNOTS OR LESS. WINDS TURN TO THE EAST-NORTHEAST MONDAY NIGHT INTO TUESDAY AS A LOW PRESSURE SYSTEM MOVES ACROSS THE UPPER OHIO VALLEY/LOWER GREAT LAKES. TRACK OF THE LOW STILL IN DOUBT. WINDS/WAVES COULD APPROACH SMALL CRAFT ADVISORY CRITERIA. FOR NOW WILL CONTINUE TO MONITOR. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...LOMBARDY SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...DJB MARINE...DJB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
331 PM EDT SAT SEP 29 2012 .SYNOPSIS... ISSUED AT 316 PM EDT SAT SEP 29 2012 ONE AREA OF LOW PRESSURE WILL DEVELOP OVER NEW ENGLAND TONIGHT AND SUNDAY. THIS SYSTEM WILL BE TO FAR EAST TO CREATE RAIN HERE IN WESTERN MICHIGAN. HIGH PRESSURE IN ONTARIO WILL BUILD SOUTH INTO WESTERN LOWER MICHIGAN CREATING FAIR CONDITIONS WITH COOL NIGHTS AND NEAR SEASONABLY WARM DAYS INTO MONDAY. A WEAK COLD FRONT WILL APPROACH THE REGION FROM THE NORTHWEST TUESDAY INTO WEDNESDAY AS A LOW PRESSURE SYSTEM LIFTS OUT OF THE GULF OF MEXICO. AS A RESULT THE REGION MAY SEE SOME SHOWERS ARRIVING. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 316 PM EDT SAT SEP 29 2012 THE MAIN CHALLENGE DEALS WITH THE RISK FOR FROST TONIGHT. OVERALL THE TREND OF TRACKING/FORMING THE SURFACE LOW FURTHER EAST CONTINUES. LOOKS LIKE IT WILL END UP OVER NEW ENGLAND. HERE IN WRN LOWER MI...SKIES WILL FEATURE MUCH LESS CLOUD COVER AS A RESULT IT APPEARS. THIS OPENS UP THE RISK FOR FROST ESPECIALLY WITH HIGH PRESSURE NOW SHOWN TO DROP SOUTHWARD OUT OF ONTARIO. HOWEVER THE HRRR RUC AND EVEN THE NAM ARE SHOWING LOW LEVEL MOISTURE AND A RISK FOR STRATUS TO DEVELOP OVER NORTHEAST LOWER TONIGHT...THEN DROP SOUTHWEST AND EXPAND INTO SOUTHWEST LOWER MI LATE TONIGHT. WILL KEEP THE FROST OUT OF THE FORECAST FOR NOW...BUT THIS SHOULD BE MONITORED CLOSELY AS HEADLINES MAY BE REQUIRED IF THE CLOUDS DO NOT DEVELOP. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 316 PM EDT SAT SEP 29 2012 TEMPS WILL AVERAGE ABOVE NORMAL TUESDAY BUT SOME CLOUDS FROM LOW PRESSURE TRACKING NE THROUGH THE OH VALLEY REGION WILL MOVE IN. WE HAVE INTRODUCED MENTION OF A SLIGHT CHC OF LIGHT RAIN SHOWERS FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT INTO WEDNESDAY IN ASSOCIATION WITH THAT SYSTEM (MAINLY SE OF GRR). TEMPS WILL REMAIN ABOVE NORMAL WEDNESDAY THROUGH THURSDAY AFTERNOON AS FLOW BECOMES SOUTHWESTERLY IN ADVANCE OF A STRONG COLD FRONT. THAT LOW PRESSURE SYSTEM AND COLD FRONT WILL BRING A CHC OF SHOWERS THURSDAY NIGHT THROUGH FRIDAY. AN UNSEASONABLY COOL AIRMASS WILL MOVE IN BEHIND THAT FRONT FRIDAY THROUGH SATURDAY WHEN HIGH TEMPS WILL ONLY REACH THE 50S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY) ISSUED AT 1200 PM EDT SAT SEP 29 2012 VFR CONDITIONS ARE EXPECTED THROUGH 18Z SUNDAY. LINGERING MID TO HIGH LEVEL CLOUDS ARE QUICKLY DRIFTING SOUTH AND OUT OF THE AREA AND A DRY AIRMASS IS MOVING IN. NW WINDS TO NEAR 10 KTS THIS AFTN WILL DIMINISH TO 5 KTS OR LESS THIS EVENING AND VEER TO THE NE. NE WINDS OF 5 TO 10 KTS ARE ANTICIPATED TOMORROW. && .MARINE... ISSUED AT 316 PM EDT SAT SEP 29 2012 WAVES WILL BE BUILDING AN REACH VALUES CLOSE TO SMALL CRAFT ADVISORY CRITERIA TONIGHT UP AROUND LITTLE AND BIG SABLE POINTS. THEN ON SUNDAY AS A NORTHERLY FLOW PERSISTS...WAVES SOUTH OF SOUTH HAVEN WILL ALSO END UP CLOSE TO CRITERIA. I THOUGHT MOST VALUES WOULD BE JUST UNDER CRITERIA SO NO HEADLINE AT THIS TIME. && .HYDROLOGY... ISSUED AT 316 PM EDT SAT SEP 29 2012 NO HYDRO ISSUES EXPECTED. ANY RAINFALL IS FORECASTED TO BE LIMITED AND NOT ENOUGH TO CAUSE SIGNIFICANT RISES. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ SYNOPSIS...MJS SHORT TERM...MJS LONG TERM...LAURENS AVIATION...LAURENS HYDROLOGY...MJS MARINE...MJS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
345 PM EDT SAT SEP 29 2012 .SYNOPSIS... A POTENT UPPER LEVEL LOW WILL DROP SOUTH INTO THE REGION TONIGHT...BRINGING AN INCREASING CHANCE FOR RAIN SHOWERS TONIGHT AND SUNDAY. INTERMITTENT SHOWERS WILL TAPER OFF IN WESTERN SECTIONS SUNDAY NIGHT...BUT WILL LINGER EAST OF LAKE ONTARIO INTO MONDAY. && .NEAR TERM /THROUGH SUNDAY/... FOR THE REMAINDER OF THIS AFTERNOON...SHOWERS WHICH WERE FORECAST BY THE HRRR AND RGEM HAVE YET TO DEVELOP AS OF 300 PM. THE ATMOSPHERE IS MARGINALLY UNSTABLE...BUT IT WILL LIKELY TAKE A CONVERGENCE BOUNDARY TO INITIATE SHOWERS WITH THE UPPER LOW STILL WELL NORTH OF LAKE HURON. BECAUSE THESE MODELS WERE TOO AGGRESSIVE IN DEVELOPING A SW FLOW OFF LAKE ERIE...EXPECT THEIR QPF FIELDS SUFFERED. WHILE A STRAY SHOWER CAN/T BE RULED OUT SOUTH OF A BUFFALO TO ROCHESTER LINE...COVERAGE SHOULD BE QUITE SPARSE. LATE AFTERNOON TEMPERATURES WILL RANGE FROM THE UPPER 50S TO LOWER 60S...WARMEST NEAR THE LAKES. FOR TONIGHT...THE UPPER LOW WILL DROP SOUTHWARD...EVENTUALLY SETTLING ACROSS WESTERN NEW YORK SUNDAY MORNING. THIS WILL BRING TWO REASONS FOR AN INCREASING CHANCE OF SHOWERS. THE FIRST IS SIMPLY ASSOCIATED WITH THE UPPER LOW...AS IT WILL ENHANCE LIFT AS IT MOVES INTO THE REGION. THE LAKES WILL ALSO PROVIDE AN ENHANCEMENT...WITH LAKE INDUCED CAPES RISING TO AROUND 1000 J/KG AS THE UPPER LOW COOLS TEMPERATURES ALOFT. FOLLOWING A LARGELY DRY START TO THE EVENING...EXPECT SOME SCATTERED SHOWERS TO MOVE INTO FAR WESTERN SECTIONS. MEANWHILE...NIGHTFALL SHOULD HELP FOCUS A NE FLOW ON LAKE ONTARIO INTO A BAND OF SHOWERS ON THE SOUTHERN THIRD OF THE LAKE...STEAMING INTO FAR NORTHERN NIAGARA COUNTY AND THE NIAGARA ESCARPMENT. A SIMILAR STORY SHOULD PLAY OUT ON LAKE ERIE...BUT THIS BAND SHOULD BE AS ORGANIZED ON WESTERN PORTIONS OF THE LAKE GIVEN THE SHORTER FETCH. AS THE NIGHT GOES ON...WINDS WILL SHIFT WITH A MORE NORTHERLY COMPONENT. THIS WILL LIKELY PUSH THESE SHOWERS ONSHORE INTO NIAGARA/ORLEANS COUNTIES LATE TONIGHT. ELSEWHERE...SEE A CHANCE OF SHOWERS IN WESTERN LOCATIONS...THIS MAINLY DUE TO THE UPPER LOW AND ANY LEFT OVER AFTERNOON SHOWERS. FOR SUNDAY...THE UPPER LOW WILL CONTINUE TO PUSH MOISTURE ACROSS THE REGION. MEAN QPF AMONG MODEL GUIDANCE (GFS/NAM/RGEM) IS QUITE UNIMPRESSIVE...WITH GENERALLY LIGHT RAINFALL AMOUNTS AVERAGING LESS THAN A TENTH OF AN INCH. GIVEN THE CONVECTIVE NATURE OF THIS...CAN SEE A FEW SPOTS DODGING THE SHOWERS...HOWEVER THE MAJORITY OF LOCATIONS SHOULD HAVE AT LEAST SOME MEASURABLE RAIN. WENT WITH HIGH LIKELY POPS AS A COMPROMISE HERE...BUT KEEP IN MIND RAINFALL AMOUNTS SHOULD GENERALLY BE LIGHT WITH THIS EVENT...WITH THE POSSIBLE EXCEPTION OF LAKE EFFECT RAIN SHOWERS IN THE NIAGARA FRONTIER LATE TONIGHT INTO SUNDAY MORNING. SHOWERS WILL GRADUALLY END FROM WEST TO EAST AS THE UPPER LEVEL LOW SLOWLY MOVES TO THE EAST ON SUNDAY. OTHERWISE...THE CLOUD COVER WILL KEEP TEMPERATURES FROM CHANGING MUCH FROM TONIGHT TO SUNDAY. LOWS WILL MAINLY BE IN THE MID AND UPPER 40S ACROSS THE CWA FOR TONIGHT...WITH HIGHS IN THE UPPER 50S SUNDAY. WHILE IT SHOULD BE MAINLY CLOUDY DURING THE PERIOD...PATCHY CLEARING IS POSSIBLE...WITH ANY CLEARING PRONE TO MORE DIURNAL SWINGS. AREAS OF FOG APPEAR LIKELY EAST OF LAKE ONTARIO...WHERE THE NORTHEAST FLOW SHOULD HELP PUSH IN LOW CLOUDS AND FOG IN. THIS IS SHOWN BY BOTH THE NAM/RAP BUFKIT SOUNDINGS. THERE ALSO MAY BE PATCHY FOG IN THE VALLEYS OF THE SOUTHERN TIER...WITH FOG POSSIBLE IN ANY AREAS OF PROLONGED CLEARING TONIGHT. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... THE DEEP CLOSED LOW OVER NEW YORK STATE WILL FINALLY LIFT OUT TO NEW ENGLAND SUNDAY NIGHT...BEFORE SETTLING OVER THE CANADIAN MARITIMES ON MONDAY. ONGOING SHOWERS ASSOCIATED WITH THE LOW WILL TAPER OFF SUNDAY NIGHT. THE EXCEPTION TO THIS GENERAL TREND WILL BE EAST OF LAKE ONTARIO WHERE A WEST TO NORTHWEST FETCH OFF THE LAKE AND MARGINALLY COLD AIR ALOFT WILL GENERATE SOME LAKE EFFECT RAIN SHOWERS. THERE MAY ALSO BE A LINGERING CONTRIBUTION FROM MOISTURE WRAPPING AROUND THE SLOWLY DEPARTING UPPER LOW. A SHALLOWER LAYER OF MOISTURE IS EXPECTED TO BE IN PLACE EAST OF LAKE ERIE. THIS WILL LIKELY PRECLUDE THE DEVELOPMENT OF LAKE EFFECT RAIN...BUT SOME CLOUDS MAY LINGER IN THE WESTERLY UPSLOPE FLOW. ANY LINGERING INFLUENCE FROM THE DEPARTING LOW AND LAKE EFFECT SHOULD END MONDAY MORNING. OTHERWISE...WEAK HIGH PRESSURE SITUATED BETWEEN THE DEPARTING LOW CANADIAN MARITIMES LOW AND A SECOND LOW IN PLACE OVER THE LOWER MISSISSIPPI VALLEY WILL BRING FAIR WEATHER AND A RETURN TO SOME SUNSHINE...ESPECIALLY DURING THE AFTERNOON. AREA TEMPERATURES WILL BE CLOSE TO SEASONAL AVERAGES. MONDAY NIGHT WILL FEATURE AN INCREASE IN CLOUDS AS A DEEP LAYERED SOUTHERLY FLOW TAPS MOISTURE FROM THE NORTHERN GULF STATES. WARM AIR ADVECTION ON THE NOSE OF A MODEST LOW LEVEL JET THAT WILL BE MOVING NORTH ACROSS THE OHIO VALLEY WILL A CHANCE OF RAIN SHOWERS TO THE SOUTHERN TIER BEFORE DAYBREAK TUESDAY. THE INCREASE IN CLOUDS AND DEEPENING SOUTHERLY FLOW WILL KEEP TEMPERATURES FAIRLY MILD...WITH MOST AREAS EXPECTED TO READINGS IN THE LOWER 50S. ON TUESDAY...THE LOWER MISSISSIPPI VALLEY UPPER LOW WILL BEGIN TO OPEN UP AS A DEEPENING TROUGH DIGS SOUTH ACROSS THE NORTHERN ROCKIES AND NORTHERN PLAINS STATES. AS THE ATTENDANT SURFACE LOW AND ITS ASSOCIATED WARM FRONT LIFT TO THE NORTH...SHOWERS WILL SPREAD NORTH ACROSS OUR CWA. THIS TREND WILL CONTINUE INTO TUESDAY NIGHT AS THE WARM FRONT LIFTS NORTH TOWARD NEW YORK STATE. STABILITY INDICES SUGGEST A POSSIBILITY OF ELEVATED CONVECTION AS THE WARM FRONT LIFTS SLOWLY TO THE NORTH. THE SOUTHERLY FLOW WILL ALLOW TEMPERATURES TO WARM INTO THE MID AND UPPER 60S TUESDAY...IN SPITE OF THE INCREASING CHANCES FOR RAIN. RATHER MILD CONDITIONS WILL CONTINUE TUESDAY NIGHT WITH TEMPERATURES EXPECTED TO HOLD STEADY IN THE MID TO UPPER 60S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... A PERIOD OF WARMER THAN AVERAGE TEMPERATURES WITH SOME LATE SEPTEMBER CONVECTION IS POSSIBLE DURING THE FIRST PART OF THIS FORECAST PERIOD...BEFORE A TRANSITION TO MID FALL-LIKE WEATHER TAKES PLACE ON SATURDAY. THE UPPER TROUGH THAT WILL BE IN PLACE OVER THE TENNESSEE VALLEY WEDNESDAY MORNING IS FORECAST TO NORTHEAST TOWARD THE LOWER GREAT LAKES WEDNESDAY AFTERNOON...THEN SHIFT EAST ACROSS NEW YORK STATE WEDNESDAY NIGHT. THE LIFT ASSOCIATED WITH THIS IMPULSE...COMBINED WITH THE ONGOING WARM AIR ADVECTION PATTERN...WILL BRING A CHANCE FOR A FEW MORE SHOWERS. THERE MAY BE SUFFICIENT ELEVATED INSTABILITY TO RESULT IN SCATTERED CONVECTION. IT WILL BE EVEN WARMER ON WEDNESDAY WITH TEMPERATURES EXPECTED TO RISE WELL INTO THE 60S AND MAYBE EVEN LOWER 70S ACROSS THE LOWER ELEVATIONS OF THE LAKE PLAINS. THE UPPER LEVEL TROUGH IS FORECAST TO SHIFT EAST INTO NEW ENGLAND ON THURSDAY. RIDGING BEHIND THE TROUGH SHOULD BRING FAIR WEATHER FOR THURSDAY AND ANOTHER DAY OF UNSEASONABLE WARM TEMPERATURES. A POTENT COLD FRONT ASSOCIATED WITH A DEEPENING CANADIAN TROUGH WILL CROSS THE CWA ON FRIDAY. THIS WILL BRING ANOTHER CHANCE FOR SHOWERS AND POSSIBLE THUNDERSTORMS. STRONG COLD AIR ADVECTION SETTING BEHIND THE FRONT WILL BRING A CHANCE FOR SOME LAKE EFFECT PCPN...WHILE TEMPERATURES RANGE THROUGH THE 50S ON SATURDAY. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... AN UPPER LEVEL LOW WILL DROP ACROSS THE REGION OVERNIGHT...SETTLING ACROSS WESTERN NEW YORK SUNDAY. THIS WILL BRING AN UNSETTLED PATTERN...WITH A FAIR AMOUNT OF LOW LEVEL MOISTURE...BUT ONLY SPARSE SHOWER COVERAGE. FOR THE REMAINDER OF TODAY...EXPECT MAINLY VFR CONDITIONS...OUTSIDE OF SPOTTY AREAS OF SHOWERS AND LOWER CIGS. WITH THE APPROACH OF THE UPPER LOW...AND A PERSISTENT NE FLOW TONIGHT...EXPECT MOISTURE TO INCREASE WHICH WILL LIKELY LOWER CIGS TO MVFR OR LOWER IN SPOTS. TIMING THIS IS A BIT OF A CHALLENGE...SINCE LOWER CIGS WILL BUILD IN GRADUALLY REFLECTING THE SLOW MOVEMENT OF THE UPPER LOW. THE CHANCE FOR SHOWERS WILL ALSO INCREASE...WITH A FAIRLY GOOD CHANCE FOR SOME LIGHT SHOWERS BY SUNDAY MORNING. THE BEST CHANCE FOR IFR OR LOWER CONDITIONS IS AT ART...WHERE A NE UPSLOPE FLOW WILL LIKELY DEVELOP LATE TONIGHT...WHICH COULD RESULT IN VERY LOW CIGS AND OR FOG. THIS SAID...THE MOIST FLOW COULD POTENTIALLY PRODUCE IFR OR LOWER CIGS...AND EVEN FOG...AT ALL TAF SITES LATE TONIGHT THROUGH SUNDAY MORNING...HOWEVER FORECAST HEDGES A BIT MORE OPTIMISTIC AT BUF/IAG/ROC/JHW THAN AT ART. OUTLOOK... SUNDAY AFTERNOON AND NIGHT...MVFR/IFR WITH INTERMITTENT SHOWERS. MONDAY...MAINLY VFR. TUESDAY AND WEDNESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS. THURSDAY...MAINLY VFR. && .MARINE... AN UPPER LEVEL LOW WILL DROP SOUTH OUT OF CANADA THROUGH SUNDAY. A FEW PERIODS OF NORTH TO NORTHEAST WINDS IN THE 10-15 KNOT RANGE WILL BRING CHOPPY WAVES TO THE SOUTH SHORE OF LAKE ONTARIO AT TIMES...BUT CONDITIONS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. A SURFACE LOW WILL DEEPEN OVER NEW ENGLAND LATER SUNDAY NIGHT AND MONDAY AND BRING INCREASING WESTERLY WINDS TO LAKE ONTARIO. THIS WILL LIKELY BRING A PERIOD OF SMALL CRAFT ADVISORY CONDITIONS FROM LATER SUNDAY NIGHT THROUGH MONDAY...ESPECIALLY ON THE EAST HALF. COLD AIR ALOFT AND SOME CONVECTIVE SHOWERS WILL BRING THE POTENTIAL FOR WATERSPOUTS LATER TONIGHT INTO SUNDAY MORNING ON BOTH LAKES ERIE AND ONTARIO. WATERSPOUTS ARE MOST COMMON IN AND NEAR BANDS OF CLOUDS LAKE EFFECT CLOUDS AND SHOWERS WHERE LOW LEVEL CONVERGENCE IS LOCALLY MAXIMIZED. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...NONE. MARINE...NONE. && $$ SYNOPSIS...APFFEL NEAR TERM...APFFEL SHORT TERM...TJP LONG TERM...TJP AVIATION...APFFEL MARINE...APFFEL/TJP
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
133 PM EDT SAT SEP 29 2012 .SYNOPSIS... RIDGE ACROSS THE AREA TODAY WILL BEGIN TO WEAKEN. AN UPPER LEVEL DISTURBANCE OVER QUEBEC WILL MOVE SOUTH TODAY AND WILL AFFECT THE AREA LATE TONIGHT AND SUNDAY. HIGH PRESSURE WILL MOVE IN FOR SUNDAY NIGHT AND PART OF MONDAY BEFORE MOVING NORTH AS LOW PRESSURE FROM THE GULF OF MEXICO HEADS INTO THE AREA. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST RADAR AND SATELLITE IMAGERY INDICATE BAND OF WHAT APPEARS TO BE SHOWERS MOVING SOUTHEAST TOWARD THE AREA CONTINUES TO REMAIN WEAK. RADAR SHOWS THAT ACTIVITY IS LIKELY VIRGA. A QUICK LOOK OUT THE WINDOW CONFIRMS THIS SUSPICION. HRRR MODEL HAS ALSO BACKED OFF ON PRECIPITATION IN THE NORTHEAST AS WELL. SO WILL KEEP AREA DRY THROUGH THE REST OF THE AFTERNOON. TEMPERATURES WILL CONTINUE TO CLIMB INTO MAX FORECAST HIGHS FOR THE DAY. SUNSHINE WILL HELP TO BOOST TEMPERATURES AS WELL. COOLER READINGS WILL BE IN THE EAST THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... THE FORECAST IS NOT CLEAR CUT FOR ANY PERIOD. AN UPPER LOW OVER QUEBEC WILL BE MOVING SOUTH TODAY AND WILL AFFECT THE FORECAST AREA FOR TONIGHT INTO SUNDAY. THIS RUN OF THE MODELS ARE MUCH DRIER WITH THIS FEATURE. KEPT CLOSE TO THE PREVIOUS FORECAST. JUST WENT CHANCE POPS TONIGHT AND THEN LIKELY SUNDAY OVER NE OH AND NW PA. A BIG QUESTION IS HOW FAR WEST WILL THE THREAT BE. TOLEDO TO FINDLAY IS ON THE EDGE. BUT WITH THE CIRCULATION AROUND THE LOW CAN`T RULE OUT SOME LIGHT SHOWERS FOR THAT AREA. CONTINUED WITH WATERSPOUTS ON THE LAKE SUNDAY AND ADDED THUNDER TO THE LAKE AND NE OH AND NW PA BASED ON THE LAKE AND 500 MB TEMPERATURE DIFFERENCE BEING NEAR 43C. SMALL HAIL IS ALSO POSSIBLE...NOT INCLUDED IN THE ZONES/GRIDS YET. AS THE UPPER LOW MOVES EAST SUNDAY NIGHT THE THREAT OF SHOWERS WILL DECREASE FROM WEST TO EAST. HIGH PRESSURE WILL BUILD IN LATE SUNDAY NIGHT AND THEN BEGIN MOVING NORTH SUNDAY AS LOW PRESSURE HEADS TOWARDS THE FORECAST AREA FOR MONDAY NIGHT. THIS IS A MODEL CHANGE SO NOT GOING TO WILD IN BRINGING IN THE SHOWERS TOO QUICKLY...BUT THE TIMING MAY NEED TO BE ADJUSTED. IT IS POSSIBLE THAT SOME SHOWERS COULD MAKE IT INTO THE SOUTHERN PORTION OF THE FORECAST AREA LATE MONDAY AFTERNOON. THE UPPER TROF ASSOCIATED WITH THIS SURFACE LOW WILL BE OVER THE REGION INTO MID WEEK. THE MODELS HANDLE IT DIFFERENTLY...THE ECMWF HAS A CLOSED LOW. ON THE EDGE ABOUT THAT...ITS HISTORY THE LAST FEW WEEKS HAS NOT BEEN REAL GOOD WITH CLOSED LOWS. NONE THE LESS A THREAT OF SHOWERS WILL EXIST...LIKELY POPS MAY EVEN BE NEEDED. USED A BLEND OF GUIDANCE FOR THE TEMPERATURES AS THE FORECAST IS TRICKY WITH ALL THE MODEL DIFFERENCES. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... WEDNESDAY THE GFS AND ECMWF ARE OUT OF SYNC. GFS HAS STRONG LOW PRESSURE SYSTEM OVER LAKE ERIE...WHILE ECMWF HAS A RIDGE OF HIGH PRESSURE OVER THE EASTERN LAKES. FOR NOW WILL CONTINUE WITH THE HPC SOLUTION...WHICH IS THE ECMWF. BOTH MODELS HAVE WEAK RIDGE OVER THE AREA THURSDAY SO WILL REMOVE ALL MENTION OF PRECIP. TREND FOR THE TWO MODELS IS SIMILAR FOR THE END OF THE WORK WEEK WITH A LOW PRESSURE SYSTEM MOVING ACROSS THE LAKES DRAGGING A COLD FRONT ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY MORNING. GFS IS FASTER OF THE TWO MODELS...FOR NOW WILL GO WITH THE TIMING OF THE ECMWF WHICH HAS THE FRONT INTO NW OH BY 12Z FRIDAY AND EAST OF THE AREA BY LATER AFTERNOON. && .AVIATION /17Z SATURDAY THROUGH WEDNESDAY/... QUIET WEATHER WILL CONTINUE FOR MOST OF THE TAF PERIOD. SOME PASSING MID LEVEL CLOUDS WILL CONTINUE THROUGH THE EVENING HOURS. THE LATEST GUIDANCE IS SUGGESTING SOME CU IS POSSIBLE THIS AFTERNOON IN THE EAST. MOIST LOW LEVEL AIR WILL BEGIN TO ARRIVE LATE TONIGHT AS AN UPPER LOW APPROACHES FROM THE NE. WILL GRADUALLY LOWER CIGS OVERNIGHT. BY DAYBREAK WILL NEED A MENTION OF SHOWERS OVER ABOUT THE EAST 1/3 TO 1/2 OF THE AREA. LOT`S OF MVFR CIGS CLOSER TO THE LOW CENTER BUT THE NEW GUIDANCE KEEPS THINGS VFR. DON`T THINK THAT IS REALISTIC AND EXPECT PATCHY MVFR CIGS BY THE END OF THE PERIOD OVER NE OH AND NW PA. LIGHT W TO NW FLOW WILL BECOME VARIABLE THIS EVENING AND THEN NE ON SUNDAY MORNING. .OUTLOOK...NON-VFR PROBABLE SUNDAY AND AGAIN ON TUESDAY IN SHRA. && .MARINE... HIGH PRESSURE WILL REMAIN OVER THE LAKE THROUGH SATURDAY. GRADIENT SHOULD BE WEAK ENOUGH FOR EXPECT LAKE/LAND BREEZES TO DEVELOP BOTH TODAY AND SATURDAY. WEAK TROUGH/LOW MOVES ACROSS THE LAKE SUNDAY BUT CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. WITH WINDS GENERALLY 10 KNOTS OR LESS. WINDS TURN TO THE EAST-NORTHEAST MONDAY NIGHT INTO TUESDAY AS A LOW PRESSURE SYSTEM MOVES ACROSS THE UPPER OHIO VALLEY/LOWER GREAT LAKES. TRACK OF THE LOW STILL IN DOUBT. WINDS/WAVES COULD APPROACH SMALL CRAFT ADVISORY CRITERIA. FOR NOW WILL CONTINUE TO MONITOR. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...LOMBARDY SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...KUBINA MARINE...DJB
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1240 PM EDT SAT SEP 29 2012 .SYNOPSIS... RIDGE ACROSS THE AREA TODAY WILL BEGIN TO WEAKEN. AN UPPER LEVEL DISTURBANCE OVER QUEBEC WILL MOVE SOUTH TODAY AND WILL AFFECT THE AREA LATE TONIGHT AND SUNDAY. HIGH PRESSURE WILL MOVE IN FOR SUNDAY NIGHT AND PART OF MONDAY BEFORE MOVING NORTH AS LOW PRESSURE FROM THE GULF OF MEXICO HEADS INTO THE AREA. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST RADAR AND SATELLITE IMAGERY INDICATE BAND OF WHAT APPEARS TO BE SHOWERS MOVING SOUTHEAST TOWARD THE AREA CONTINUES TO REMAIN WEAK. RADAR SHOWS THAT ACTIVITY IS LIKELY VIRGA. A QUICK LOOK OUT THE WINDOW CONFIRMS THIS SUSPICION. HRRR MODEL HAS ALSO BACKED OFF ON PRECIPITATION IN THE NORTHEAST AS WELL. SO WILL KEEP AREA DRY THROUGH THE REST OF THE AFTERNOON. TEMPERATURES WILL CONTINUE TO CLIMB INTO MAX FORECAST HIGHS FOR THE DAY. SUNSHINE WILL HELP TO BOOST TEMPERATURES AS WELL. COOLER READINGS WILL BE IN THE EAST THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... THE FORECAST IS NOT CLEAR CUT FOR ANY PERIOD. AN UPPER LOW OVER QUEBEC WILL BE MOVING SOUTH TODAY AND WILL AFFECT THE FORECAST AREA FOR TONIGHT INTO SUNDAY. THIS RUN OF THE MODELS ARE MUCH DRIER WITH THIS FEATURE. KEPT CLOSE TO THE PREVIOUS FORECAST. JUST WENT CHANCE POPS TONIGHT AND THEN LIKELY SUNDAY OVER NE OH AND NW PA. A BIG QUESTION IS HOW FAR WEST WILL THE THREAT BE. TOLEDO TO FINDLAY IS ON THE EDGE. BUT WITH THE CIRCULATION AROUND THE LOW CAN`T RULE OUT SOME LIGHT SHOWERS FOR THAT AREA. CONTINUED WITH WATERSPOUTS ON THE LAKE SUNDAY AND ADDED THUNDER TO THE LAKE AND NE OH AND NW PA BASED ON THE LAKE AND 500 MB TEMPERATURE DIFFERENCE BEING NEAR 43C. SMALL HAIL IS ALSO POSSIBLE...NOT INCLUDED IN THE ZONES/GRIDS YET. AS THE UPPER LOW MOVES EAST SUNDAY NIGHT THE THREAT OF SHOWERS WILL DECREASE FROM WEST TO EAST. HIGH PRESSURE WILL BUILD IN LATE SUNDAY NIGHT AND THEN BEGIN MOVING NORTH SUNDAY AS LOW PRESSURE HEADS TOWARDS THE FORECAST AREA FOR MONDAY NIGHT. THIS IS A MODEL CHANGE SO NOT GOING TO WILD IN BRINGING IN THE SHOWERS TOO QUICKLY...BUT THE TIMING MAY NEED TO BE ADJUSTED. IT IS POSSIBLE THAT SOME SHOWERS COULD MAKE IT INTO THE SOUTHERN PORTION OF THE FORECAST AREA LATE MONDAY AFTERNOON. THE UPPER TROF ASSOCIATED WITH THIS SURFACE LOW WILL BE OVER THE REGION INTO MID WEEK. THE MODELS HANDLE IT DIFFERENTLY...THE ECMWF HAS A CLOSED LOW. ON THE EDGE ABOUT THAT...ITS HISTORY THE LAST FEW WEEKS HAS NOT BEEN REAL GOOD WITH CLOSED LOWS. NONE THE LESS A THREAT OF SHOWERS WILL EXIST...LIKELY POPS MAY EVEN BE NEEDED. USED A BLEND OF GUIDANCE FOR THE TEMPERATURES AS THE FORECAST IS TRICKY WITH ALL THE MODEL DIFFERENCES. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... WEDNESDAY THE GFS AND ECMWF ARE OUT OF SYNC. GFS HAS STRONG LOW PRESSURE SYSTEM OVER LAKE ERIE...WHILE ECMWF HAS A RIDGE OF HIGH PRESSURE OVER THE EASTERN LAKES. FOR NOW WILL CONTINUE WITH THE HPC SOLUTION...WHICH IS THE ECMWF. BOTH MODELS HAVE WEAK RIDGE OVER THE AREA THURSDAY SO WILL REMOVE ALL MENTION OF PRECIP. TREND FOR THE TWO MODELS IS SIMILAR FOR THE END OF THE WORK WEEK WITH A LOW PRESSURE SYSTEM MOVING ACROSS THE LAKES DRAGGING A COLD FRONT ACROSS THE AREA THURSDAY NIGHT INTO FRIDAY MORNING. GFS IS FASTER OF THE TWO MODELS...FOR NOW WILL GO WITH THE TIMING OF THE ECMWF WHICH HAS THE FRONT INTO NW OH BY 12Z FRIDAY AND EAST OF THE AREA BY LATER AFTERNOON. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR CONDITIONS WILL CONTINUE SATURDAY. CLOUDS WILL THICKEN AND LOWER THROUGH THE DAY AS UPPER LEVEL TROUGH SWINGS ACROSS THE AREA. LIGHT S-SW WINDS NEAR LAKESHORE WILL BECOME ONSHORE THIS AFTERNOON. SURFACE TROUGH WILL SWING ACROSS EASTERN LAKES SUNDAY...WHICH SHOULD BRING SOME SHOWERS TO EASTERN HALF OF THE FORECAST AREA. WILL SEE RAIN SUNDAY BUT CONFIDENCE IS LOW AS TO HOW MUCH. MODEL RUNS TODAY HAVE BEEN MUCH DRIER THAN PREVIOUS 2 DAYS. .OUTLOOK...NON-VFR PROBABLE SUNDAY AND AGAIN ON TUESDAY IN SHRA. && .MARINE... HIGH PRESSURE WILL REMAIN OVER THE LAKE THROUGH SATURDAY. GRADIENT SHOULD BE WEAK ENOUGH FOR EXPECT LAKE/LAND BREEZES TO DEVELOP BOTH TODAY AND SATURDAY. WEAK TROUGH/LOW MOVES ACROSS THE LAKE SUNDAY BUT CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. WITH WINDS GENERALLY 10 KNOTS OR LESS. WINDS TURN TO THE EAST-NORTHEAST MONDAY NIGHT INTO TUESDAY AS A LOW PRESSURE SYSTEM MOVES ACROSS THE UPPER OHIO VALLEY/LOWER GREAT LAKES. TRACK OF THE LOW STILL IN DOUBT. WINDS/WAVES COULD APPROACH SMALL CRAFT ADVISORY CRITERIA. FOR NOW WILL CONTINUE TO MONITOR. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KIELTYKA NEAR TERM...LOMBARDY SHORT TERM...KIELTYKA LONG TERM...DJB AVIATION...DJB MARINE...DJB