Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 230905 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 405 AM EST SUN NOV 23 2014 .SYNOPSIS...
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A LOW WILL LIFT FROM THE SOUTHERN PLAINS TO THE EASTERN GREAT LAKES REGION TODAY INTO TOMORROW. AS IT DOES SO, FIRST A WARM FRONT WILL LIFT THROUGH OUR REGION TONIGHT, THEN A COLD FRONT WILL SWEEP THROUGH MONDAY. HIGH PRESSURE FOLLOWS LATER TUESDAY. A COASTAL STORM WILL DEVELOP OFF THE CAROLINA COAST WEDNESDAY BEFORE MOVING EAST OF NEW ENGLAND BY THANKSGIVING. IN ITS WAKE, A COLD AIR MASS SETTLES IN OVER THE OHIO VALLEY AT THE END OF THE WEEK.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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HIGH PRES WILL MOVE EWD AND OFF THE COAST TODAY. AS IT DOES, SWLY FLOW WILL INCREASE AND EXPECT A MUCH WARMER DAY AS HIGH MAKE IT INTO THE 50S OVER MOST OF THE AREA. CLOUDS WILL ALSO INCREASE BY LATE IN THE DAY. LOW PRES DEVELOPING OVER THE SRN PLAINS WILL MOVE NEWD DURG THE DAY, BUT SHOULD REMAIN FAR ENOUGH WWD TO KEEP ANY PRECIP AWAY FROM THE REGION THOUGH THE DAY.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
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THE AFOREMENTIONED LOW WILL MOVE TOWARD THE GRTLKS TONIGHT AND BRING ITS ASSOCD WMFNT THRU ERLY AND A MARKED INCREASE IN SWLY FLOW. THERE WILL ALSO BE AN INCREASE IN MOISTURE AND THE DEVELOPMENT OF A POTENT LLJ. OVERNIGHT LOWS TONIGHT WILL NOT DROP MUCH IN RESPONSE TO THICKENING AND LOWERING CLOUDS AND THE SWLY WIND. PRECIP CHCS WILL INCREASE THRU THE NIGHT. DURG THE EVE THE BEST CHCS WILL BE S AND W WITH PRECIP EVERYWHERE AND HIGH POPS DURG THE OVERNIGHT AND ERLY MRNG HOURS. RAIN COULD BE HVY AT TIMES AND SOME THUNDER CAN NOT BE RULED OUT ESPECIALLY S AND E. QPF VALUES WILL GENLY BE BETWEEN 1/2 AND 3/4 OF AN INCH WITH LOCALLY HIGHER AMOUNTS. WITH TEMPS EXPECTED TO BE WELL ABOVE FREEZING EVERYWHERE ALL OF THE PRECIP THAT FALLS WILL BE IN THE LIQUID FORM.
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&& .LONG TERM /MONDAY THROUGH SATURDAY/...
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BIG STORY IS THE WEDNESDAY COASTAL SYSTEM...BUT BEFORE WE GET AHEAD OF OURSELVES, THERE ARE A FEW THINGS TO TALK ABOUT FOR MONDAY. HARD TO BELIEVE WE COULD GO FROM A RECORD LOW AT ALLENTOWN YESTERDAY TO NEAR RECORD HIGHS JUST TWO DAYS LATER, BUT THAT IS WHAT IS LOOKING LIKE IN THE WAKE OF THE WARM FRONT. AS MENTIONED IN THE SHORT TERM SECTION, THERE IS A HIGH CHANCE OF RAIN EARLY IN THE DAY. ALSO, AFTER SUNRISE, THERE LOOKS TO BE SOME ELEVATED INSTABILITY ABOVE THE STABLE MARINE LAYER ESPECIALLY NEAR THE COASTS IN DE AND SOUTHERN NJ. THUS, CONTINUE WITH MENTION OF THUNDER. RAIN SHOULD MOVE OUT BY THE LATE AFTERNOON/EARLY EVENING HOURS, WELL AHEAD OF THE ARRIVAL OF THE COLD FRONT. THERE IS GOOD MODEL AGREEMENT ON THE TIMING OF THE COLD FRONT...MOVING THROUGH THE REGION DURING THE OVERNIGH HOURS MONDAY NIGHT. THEN TUESDAY LOOKS LIKE A PLEASANT DAY. TEMPERATURES WILL BE 15 TO 20 DEGREES LOWER AS COMPARED TO MONDAY, BUT NEAR NORMALS. WEDNESDAY AND WEDNESDAY NIGHT...THE PERIOD EVERYONE IS TALKING ABOUT. STILL LOOKING AT A COASTAL SYSTEM DEVELOPING OFF THE CAROLINA COAST EARLY ON WEDNESDAY THEN LIFTING NORTHEAST, AND WILL BE EAST OF NEW ENGLAND BY THURSDAY. THERE ARE STILL SOME MODEL DIFFERENCES MOST NOTABLY WITH THE TRACK OF THE SURFACE LOW, THOUGH THE GAP IS CLOSING BETWEEN THE ECWMF TRACK (STILL THE FURTHEST WEST) AND THE CMC TRACK (STILL THE FURTHEST EAST), WITH THE GFS IN A COMFORTABLE MIDDLE GROUND. AS FAR AS PRECIP CHANCES, IT LOOKS VERY LIKELY THAT AREAS EAST AND SOUTH OF THE I95 CORRIDOR WILL SEE PRECIPITATION DURING THE DAY WEDNESDAY INTO WEDENSDAY EVENING. FOR AREAS NORTH AND WEST OF THE I95 CORRIDOR, THE CHANCE IS LESS, THOUGH STILL QUITE HIGH THAT THERE WILL BE WIDESPREAD PRECIP AT LEAST THROUGH THE DAY THURSDAY AS EVEN THE MIDDLE OF THE ROAD GFS SOLUTION SHOWS THE PRECEIP EXTENDING WEST OF THE POCONOS. PRECIP TYPE IS CONSIDERABLY MORE UNCERTAIN. THE ECMWF DEPICTS A MID LEVEL SOUTHWESTERLY JET OVER THE EASTERN HALF OF THE REGION, PRODUCING A ROBUST WARM LAYER WHICH WOULD MEAN VERY FEW ICE CRYSTALS ALOFT. HOWEVER, WITH THE EXCEPTION OF THE HIGHER TERRAIN OF THE POCONOS, THE ECMWF KEEPS SURFACE TEMPERATURES WELL ABOVE FREEZING, SO JUST A COLD RAIN FOR MOST OF THE REGION WHILE THERE IS A SLIM CHANCE OF FREEZING PRECIP IN THE HIGHER TERRAIN OF THE POCONOS. THE GFS ON THE OTHER HAND, HAS THE JET, AND CONSEQUENTLY MID LEVEL WARM AIR ADVECTION OVER THE OCEAN, RESULTING IN EITHER ALL RAIN OR A RAIN/SNOW MIX FOR MOST OF THE AREA, WITH ALL SNOW POSSIBLE IN THE POCONOS. WITH EITHER SOLUTION, THE CHANCES OF SIGNIFICANT ACCUMULATING SNOW DURING THE DAY SEEM SMALL (WITH THE EXCEPTION OF THE POCONOS). WHAT COULD BE THE BIGGER ISSUE IS IF OR HOW LONG THE PRECIP LINGERS THROUGH THE NIGHT TIME HOURS WEDNESDAY NIGHT. THE GFS HAS PRECIP RAPIDLY MOVING OUT BY MIDNIGHT WEDNESDAY NIGHT. WITH THIS SOLUTION, WHILE MUCH OF THE REGION COULD SEE A PERIOD OF ALL SNOW AFTER SUNSET, THE WINDOW OF OPPORTUNITY FOR ACCCUMULATING SNOW WOULD BE BRIEF. THE ECMWF ON THE OTHER HAND, LINGERS PRECIP IN THE REGION THROUGH THURSDAY MORNING, BUT KEEPS THE EASTERN HALF THE REGION ABOVE FREEZING THROUGH THE NIGHT. ALL THAT TO SAY THAT WHILE PRECIPITATION LOOKS VERY LIKELY IN THE WEDNESDAY TO WEDNESDAY NIGHT PERIOD, THE CHANCE FOR SIGNIFICANT ACCUMULATING SNOW FOR MOST OF THE REGION IS QUITE SMALL. ONCE THE PRECIP CLEARS OUT, THANKSGIVING LOOKS TO BE PLESANT, ALBEIT CHILLY WITH HIGHS ABOUT 10 DEGREES BELOW NORMAL. IN THE WAKE OF THE COASTAL LOW, A CONTENENTAL POLAR AIR MASS SETTLES IN OVER THE REGION FOR THE REMAINDER OF THE WEEK KEEPING HIGHS IN THE 30S AND 40S.
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&& .AVIATION /08Z SUNDAY THROUGH THURSDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR TO START THEN DETERIORATING CONDS THIS EVENING AND TONIGHT. HIGH PRES OVER THE REGION WILL MOVE EWD. AS IT DOES SWLY FLOW WILL STRENGTHEN ACRS THE AREA. LOW PRES WILL ALSO DEVELOP ACRS THE SRN PLAINS AND MOVE TO NR THE GRTLKS BY MON MRNG. THE ASSOCD WMFNT WITH THIS LOW WILL CROSS THE REGION TONIGHT AND THE WIND SHUD BECOME MORE SELY AND CUD GUST IN THE 15 TO 20 KT RANGE. RAIN WILL DEVELOP FROM SW TO NE DURG THE EVE HOURS AND OVERSPREAD THE ENTIRE AREA, PSBLY BECOMING HEAVY AT TIMES OVERNIGHT. A RUMBLE OF THUNDER CAN NOT BE RULED OUT OVER THE DELMARVA OR SERN NJ. CONDS ARE EXPECTED TO DETERIORATE TO MVFR AND IFR FROM EVENING ONWARD AND SOME LIFR IS PSBL THOUGH CONFIDENCE IS NOT HIGH ENOUGH TO FORECAST IT ATTM. WITH A STRONG LOW LEVEL JET EXPECTED TO DEVELOP OVERNIGHT, LLWS IS PSBL IN THE OVERNIGHT HOURS CONTINUING THRU THE MRNG. OUTLOOK... MONDAY...MVFR, AND LOCALIZED IFR CEILINGS, WILL CONTINUE THROUGH MUCH OF THE DAY ON MONDAY AS THE -RA SLOWLY MOVES OUT. MONDAY NIGHT INTO TUESDAY...CONDITIONS SHOULD RETURN TO VFR THROUGH THIS PERIOD. WEDNESDAY...A COASTAL STORM WILL LIKELY BRING MVFR OR IFR CEILINGS AND REDUCED VISIBILITIES DUE TO RA (POSSIBLY RASN AT TIMES) FOR THE REGION. IN ADDITION, EXPECT PERSISTENT NORTHERLY OR NORTHEASTERLY WINDS FOR GENERALLY THE LATTER HALF OF THE DAY. WEDENSDAY NIGHT...MVFR AND IFR CEILINGS CONTINUE. IN ADDITION, IF PRECIPITATION LINGERS FOR MUCH OF THE NIGHT, COULD SEE -SN AND REDUCED VISIBILITIES BECAUSE OF IT. THANKSGIVING...CONDITIONS SLOWLY RETURN TO VFR AND WINDS SHIFT TO WESTERLY.
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&& .MARINE...
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THE FOLLOWING CHANGES WERE MADE TO THE MARINE HEADLINES...BASED ON THE LATEST OBS, THE SCA THRU THIS MRNG HAS BEEN DROPPED. ALSO THE GALE WATCH FOR TONIGHT HAS BEEN UPGRADED TO A GALE WARNING. SEAS AND WIND ARE EXPECTED TO INCREASE IN ADVANCE OF LOW PRESSURE MOVG FROM THE SRN PLAINS TO THE GRTLKS. THE ASSOCD WMFNT WILL MOVE THRU TONIGHT AND RAIN WILL OVERSPREAD THE WATERS TONIGHT. OUTLOOK... MONDAY...GALE CONDITIONS LOOK TO CONTINUE FOR GNERALLY THE FIRST HALF OF THE DAY. THEN WINDS AND SEAS WILL BE SLOW TO DECREASE BELOW SCA CRITERIA. TUESDAY...CONDITIONS SHOULD FALL BELOW SCA CRITERIA. WEDNESDAY...WINDS AND SEAS INCREASE IN THE LATER HALF OF THE DAY ABOVE SCA CRITERIA. THANKSGIVING...WINDS AND SEAS ARE EXPECTED TO FALL BELOW SCA CRITERIA EARLY IN THE DAY AND REMAIN BELOW CRITERIA THROUGH THE REST OF THE DAY.
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&& .CLIMATE... FOR OUR EIGHT CLIMATE SITES, HERE ARE THE RECORD HIGH TEMPERATURES FOR NOVEMBER 24TH AND THE MOST RECENT YEAR OF OCCURRENCE. RECORD HIGHS 11/24: ACY: 72 SET IN 1999 PHL: 71 SET IN 1979 ILG: 73 SET IN 1979 ABE: 69 SET IN 1931 TTN: 71 SET IN 1979 GED: 75 SET IN 1992 RDG: 69 SET IN 1979 MPO: 64 SET IN 1931 && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...GALE WARNING FROM MIDNIGHT TONIGHT TO 11 AM EST MONDAY FOR ANZ430-431-450>455.
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&& $$ SYNOPSIS...JOHNSON NEAR TERM...NIERENBERG SHORT TERM...NIERENBERG LONG TERM...JOHNSON AVIATION...JOHNSON/NIERENBERG MARINE...JOHNSON/NIERENBERG CLIMATE...DRAG/KLINE

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