Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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654 FXUS61 KPHI 102059 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 359 PM EST WED FEB 10 2016 .SYNOPSIS... LOW PRESSURE OVER THE SAINT LAWRENCE VALLEY WILL MOVE INTO THE BAY OF FUNDY THURSDAY, WHILE HIGH PRESSURE OVER THE UPPER MISSISSIPPI VALLEY MOVES INTO THE MIDDLE ATLANTIC ON FRIDAY. A STRONG ARCTIC COLD FRONT WILL MOVE THROUGH OUR REGION ON SATURDAY, SWEEPING LOW PRESSURE OVER THE OUTER BANKS OF NORTH CAROLINA WELL OUT TO SEA. HIGH PRESSURE WILL MOVE INTO OUR AREA FROM THE OHIO VALLEY ON SUNDAY, AND MOVE OFF THE MID ATLANTIC COAST ON MONDAY. TWO STORM SYSTEMS ARE EXPECTED TO JOIN FORCES OVER THE MIDDLE ATLANTIC, AND MOVE UP THE EAST COAST ON TUESDAY AND WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... TONIGHT...NEGATIVE TILT SHORT WAVE PROBABLY PRODUCES FLURRIES AND SCATTERED DUSTING SNOW SHOWERS IN THE 02Z-10Z TIME FRAME, AND THOUGHT MOSTLY I-78 CORRIDOR NORTHWARD (POSSIBLY A CONNECTION TO LAKE ERIE SNOW SHOWER PLUME) BUT THERE MAY BE A BATCH THAT CROSSES THE DELMARVA, ENHANCED BY THE CHESAPEAKE BAY. ANY SNOW AMTS UNDER 1 INCH. WILL POST AN OVERNIGHT STS GRAPHIC WHICH SAYS LESS THAN 1 INCH BUT IN REALITY, EXPECTING LESS THAN 1/2 INCH WITHIN SCATTERED BANDS, MOSTLY PA. TEMPERATURES NEAR NORMAL. GUSTY WEST WINDS TO 25 MPH PROBABLY DIMINISH FOR A WHILE TONIGHT. IT MAY TEMPO CLEAR AFTER SUNSET THIS EVENING AND THAN PROBABLY PARTIALLY CLEAR TOWARD DAWN AFTER THE SHORT WAVE PASSAGE. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... PARTLY SUNNY AND BRISK. SCATTERED BRIEF SNOW SHOWERS OR FLURRIES, MAINLY I-78 NWWD WHERE VERY UNSTABLE 925-700MB LAPSE RATES AND SEMBLANCE OF A TROUGH. BTV SNOW SQUALL PARAMETER PREDICTION TOOL HAS SUPPORTIVE INDICATION. GUSTY WEST NORTHWEST WINDS TO 35 MPH 11 AM TO 3 PM. MAX TEMPS ABOUT 10F BELOW NORMAL. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
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THE MAIN CONCERN IS A PERIOD OF WIND-DRIVEN MUCH BELOW NORMAL TEMPERATURES, THE COLDEST OF THE SEASON SO FAR, SATURDAY INTO SUNDAY WITH INCREASING CONFIDENCE OF DANGEROUSLY LOW WIND CHILLS. OTHERWISE, THE FRIDAY THROUGH WEDNESDAY TIME FRAME IS GENERALLY EXPECTED TO BE UNSETTLED, WITH A CYCLONIC FLOW ALOFT. FRIDAY AND FRIDAY NIGHT, CLOUDS WILL INCREASE IN ADVANCE OF TWO SEPERATE SHORT WAVES, ONE OVER THE GREAT LAKES AND ANOTHER OVER THE MID ATLANTIC. THESE ARE EXPECTED TO REMAIN LARGELY SEPARATE, WITH ONLY A CHANCE OF SNOW SHOWERS IN THE FORECAST FOR THE FRIDAY NIGHT PORTION OF THE FORECAST. SATURDAY AND SUNDAY, WITH THE PASSAGE OF AN ARTIC COLD FRONT SATURDAY MORNING, MUCH BELOW TEMPERATURES ARE FORECAST. DURING THIS TIME FRAME, 850 MB TEMPERATURES WILL PLUNGE TO AROUND -25C AT KPHL! WE ALSO EXPECT NORTHWEST WINDS OF 15 TO 25 MPH WITH THE POTENTIAL FOR GUSTS TO 40 MPH SATURDAY INTO SATURDAY EVENING, TAPERING DOWN 10 TO 20 MPH WITH CONTINUED GUSTINESS THROUGH SUNDAY MORNING. LOW TEMPERATURES OF ZERO TO 10 BELOW ZERO ARE FORECAST FOR THE ENTIRE REGION, WHICH LEADS TO WIND CHILL VALUES DANGEROUSLY COLD IN THE 10 BELOW TO 25 BELOW ZERO RANGE SUNDAY NIGHT. MONDAY THROUGH WEDNESDAY, TEMPERATURES MODERATE QUICKLY, RETURNING TO NEAR NORMAL ON TUESDAY. THE MAIN UNCERTAINTY IS THE TRACK OF LOW PRESSURE ORGANIZING NEAR THE EAST COAST, WITH THE 12Z ECMWF NEAR THE APPALACHIANS AND THE GFS MORE OFFSHORE. IN ANY EVENT, THIS WILL BE AN UNSETTLED PERIOD OF WEATHER WITH THE POTENTIAL FOR BOTH SNOW AND RAIN.
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&& .AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. REMAINDER OF TODAY...VFR GENERALLY BKN CIGS AOA 4000 FT. WEST WIND GUST 20-25 KT. TONIGHT...VFR WITH CIGS REDEVELOPING MAINLY AOA 4000 FT. THOSE CIGS MAY BRIEFLY LOWER TO MVFR CONDS IN BANDS OF SNOW SHOWERS SOMETIME BETWEEN 03Z AND 09Z, ESPECIALLY VCNTY KABE/KTTN/KRDG. WEST WIND GUSTS TO 20 KT. CONFIDENCE: AVERAGE. THURSDAY...VFR SCT-BKN AOA 4000 FT. WEST-NORTHWEST WIND GUSTS AROUND 30 KT IN THE AFTERNOON, POSSIBLY ISOLATED 35 KT. SOME BRIEF MVFR RESTRICTIONS IN ISOLATED SNOW SHOWERS AND FLURRIES POSSIBLE VCNTY KRDG/KABE. CONFIDENCE: AVERAGE. OUTLOOK... THURSDAY NIGHT...VFR CONDITIONS. FRIDAY AND FRIDAY NIGHT...PREDOMINANTLY VFR. MVFR POSSIBLE IN SCATTERED SNOW SHOWERS. SATURDAY AND SUNDAY...VFR CONDITIONS EXPECTED. NORTHWEST WINDS 15 TO 25 KNOTS WITH GUSTS TO 30 KNOTS POSSIBLE, MAINLY SATURDAY AND SATURDAY NIGHT. MONDAY...VFR CONDITIONS. MVFR POSSIBLE IN RAIN OR SNOW SHOWERS.
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&& .MARINE...
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SST`S ARE AROUND 5 TO 8F WARMER THAN NORMAL FOR FEBRUARY AND THESE WATER TEMPERATURES WARMED ABOUT 5 DEGREES FROM THE MID JANUARY WATER TEMPERATURE TUMBLE. THE REASONING FOR THE WARMING, EVEN IN DE BAY IS NOT WELL UNDERSTOOD BY MYSELF BUT IT HAS OCCURRED AND I THINK BECOMES A MORE IMPORTANT PLAYER IN AIDING MOMENTUM TRANSFER THROUGH THESE COLD AIR ADVECTION EPISODES BY STEEPENING THE BOUNDARY LAYER LAPSE RATE. GLW CONTD. FUNNELING AND EARLIER START TO THE DEEPENING BOUNDARY LAYER MIXING FOR DE BAY SHOULD PERMIT A FEW GUSTS TO 35 KT VCNTY SJS, BWINE...LWS SOMETIME BETWEEN 1 AM AND 4 AM THURSDAY. CONFIDENCE ON THE STARTING TIME OF GALE GUSTS THERE IS AVERAGE. THEREAFTER...WNW GALE GUSTS SPREAD TO THE ATLANTIC WATERS OF NJ AND DE DURING THE MORNING, BECOMING MOST PERSISTENT THURSDAY AFTN/EVE WHEN A FEW GUSTS TO 40 KT ARE EXPECTED. HIGH CONFIDENCE. WE HAVE NO WIND DATA AT 44009 SO TO VERIFY, WE HAVE 44065 AND WE USE MULTIPLE COASTAL WIND OBSERVATIONS ADJACENT THE WATER INCLUDING NOS/USGS/WEATHERFLOW MESONET PLATFORMS. OUTLOOK... THURSDAY NIGHT...GALE WARNING IN EFFECT THROUGH 6Z...FOLLOWED BY SMALL CRAFT ADVISORY /SCA/ WINDS THROUGH EARLY FRIDAY MORNING. WINDS WILL INCREASE AGAIN TO SCA LEVELS FRIDAY NIGHT AHEAD OF AN ARCTIC COLD FRONT. WINDS INCREASE TO GALE FORCE LATE FRIDAY NIGHT AND MAY MAINTAIN GALES THROUGH SATURDAY NIGHT. A SCA MAY BE NEEDED ON SUNDAY, WITH SUB-SCA ON MONDAY.
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&& .CLIMATE... NEAR RECORD COLD IS EXPECTED FOR PORTIONS OF OUR AREA SUNDAY MORNING AND BY FAR THE COLDEST AIR OF THE SEASON SO FAR. ANTICIPATING TEMPS THROUGHOUT OUR FORECAST AREA WITHIN SEVERAL DEGREES OF ZERO (WIND IS THE EQUALIZER) ANYTIME FROM MIDNIGHT THROUGH 8 AM SUNDAY EXCEPT COLDER KMPO (NEAR -12F). THIS HAS BEEN ADVERTISED BY THE GFS/ECMWF 2M TEMPS CYCLICALLY SINCE AT LEAST THE 00Z/7 OPERATIONAL CYCLES. THEREFORE, BEST CHANCE FOR RECORD EQUALING OR EXCEEDING FOR VALENTINES DAY THE 14TH WOULD BE KABE, KTTN, KPHL AND KMPO. SNOWCOVER MAY HELP A BIT I-95 NORTHWESTWARD...AND WE`LL SEE WHERE WE ARE WITH SNOWCOVER BY THURSDAY EVENING. NEW DUSTINGS APPEAR ON THE WAY THE NEXT 30 HOURS. 2015-16 SO FAR RER 14TH ABE 8......... -1 1979 ACY 10........ -6 1979 PHL 12........ +2 1979 ILG 12........ -4 1979 RDG 10........ -4-1983 TTN 9......... 0 1916 GED 13........ -7 1979 MPO -1........ -12 1970 SO, THIS WILL BE WIND DRIVEN COLD WITH MANY AREAS EXPERIENCING WIND CHILL VALUES OF 15 TO 25 BELOW ZERO...POSSIBLY 30 BELOW IN THE HILLS AND MOUNTAINS OF NORTHWEST NEW JERSEY AND NORTHEAST PENNSYLVANIA. && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ450>455. GALE WARNING FROM 6 AM THURSDAY TO 1 AM EST FRIDAY FOR ANZ450>455. GALE WARNING FROM 1 AM TO 11 PM EST THURSDAY FOR ANZ430-431.
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&& $$ SYNOPSIS...FRANCK NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...FRANCK AVIATION...DRAG/FRANCK MARINE...DRAG/FRANCK CLIMATE...257

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