Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 302128 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 528 PM EDT THU OCT 30 2014 .SYNOPSIS... HIGH PRESSURE OVER OUR REGION WILL SHIFT TO NORTHERN NEW ENGLAND BY MORNING. LOW PRESSURE OVER OHIO FRIDAY AFTERNOON WILL JOIN FORCES WITH LOW PRESSURE EAST OF THE CAROLINAS TO FORM A STRONG STORM SOUTHEAST OF CAPE COD LATE SATURDAY. THAT STORM MOVES TO THE MARITIMES SUNDAY. STRONG HIGH PRESSURE SETTLES INTO THE CAROLINAS EARLY NEXT WEEK THEN SLIPS EASTWARD INTO THE CENTRAL ATLANTIC NEXT WEDNESDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... DUE TO DAYTIME AND STEEP LAPSE RATES THIS AFTERNOON A BROAD AREA OF MID-LEVEL CLOUDS HAS DEVELOPED ACROSS THE REGION. THIS SHOULD DISSIPATE THIS EVENING WITH THE LOSS OF DAYTIME HEATING. A CLEAR AND COOL NIGHT IS EXPECTED. NORTHWEST/NORTH WINDS SHOULD DECREASE AND BECOME VARIABLE TONIGHT. A TIGHT SPREAD WITH TEMPERATURES AMONG MEX/MET AND THE ECMWF/GFS OPERATIONAL MODELS RUN FOR LOWS TONIGHT. DID GO SLIGHTLY LOWER THAN THESE SETS IN THE PINE BARRENS WITH FAVORABLE CONDITIONS FOR RADIATIONAL COOLING. LOWS WILL GENERALLY BE IN 30`S TO RIGHT AROUND 40, WARMEST AT PHL. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... TWO AREAS OF LOW PRESSURE WILL BEGIN TO IMPACT OUR WEATHER LATE IN THIS PERIOD. THE FIRST ONE WILL BE OVER THE GREAT LAKES AND OHIO VALLEY FRIDAY WITH THE SECOND DEVELOPING OFF THE CAROLINA COASTLINE. CLOUDS FROM THE LOW PRESSURE SYSTEM TO OUR WEST SHOULD BEGIN TO MOVE IN LATE IN THE DAY. WINDS WILL SHIFT TO THE NORTHEAST IN RESPONSE TO THE LOW PRESSURE OFF THE CAROLINA COAST. THIS WILL LIKELY ALLOW ADDITIONAL CLOUDS TO ADVECT IN FROM THE OCEAN DURING THE AFTERNOON. SOME PATCHY DRIZZLE CAN NOT BE RULED OUT ALONG THE COAST. MODELED 925 MB TEMPERATURES INDICATE THE POTENTIAL FOR HIGHS IN THE UPPER 50`S ON FRIDAY FOR PHL. HOWEVER WITH CLOUDS MOVING IN IT WILL BE HARD TO REACH THESE AND KEPT HIGHS IN THE MID 50`S WITH SOME UPPER 40`S NW. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
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500 MB: A HIGH AMPLITUDE TROUGH IN THE EASTERN UNITED STATES THIS WEEKEND MOVES TO THE MARITIMES EARLY NEXT WEEK WHILE A WARMING RIDGE FOLLOWS EARLY NEXT WEEK. ANOTHER TROUGH EVOLVES IN THE EASTERN UNITED STATES LATER NEXT WEEK. TEMPERATURES: BY THE TIME THE LONG TERM FORECAST PERIOD BEGINS WE`VE CLOSED OUT THE MONTH OF OCTOBER THAT AVERAGED MORE THAN 2 DEGREES ABOVE NORMAL. NOVEMBER STARTS OUT NEAR NORMAL SATURDAY... 5 DEGREES COLDER THAN NORMAL SUNDAY WITH WIND... STILL NEARLY 5 DEGREES BELOW NORMAL MONDAY BUT WITH LESS WIND AND THEN NEAR NORMAL TUESDAY. TEMPERATURES SHOULD AVERAGE SEVERAL DEGREES ABOVE NEXT WEDNESDAY AND THURSDAY....MAYBE AS MUCH AS 10 DEGREES ABOVE NORMAL EITHER DAY. HAZARDS: GALE SATURDAY POSSIBLY LINGERING INTO SUNDAY. POSSIBLE MINOR TIDAL INUNDATION FLOODING NEAR THE TIME OF HIGH TIDE SATURDAY AFTERNOON AND NIGHT BUT THIS IS NOT LIKELY. A SMALL CHANCE OF SPOTTY WIND ADVISORY CONDITIONS SUNDAY. FORECAST BASIS: UNLESS OTHERWISE NOTED THE LONG TERM PERIOD OF THIS FORECAST IS GENERALLY BASED ON A 50 50 BLEND OF THE 12Z/30 NAM/GFS MOS FOR THE PERIOD FRIDAY NIGHT-SATURDAY NIGHT AND THEN THAT VALUE BLENDED 50 PCT WITH THE 00Z/30 ECMWF 2M TEMPS. 12Z/30 GFS MOS COMPRISES SUNDAY AND SUNDAY NIGHT...THEN THEREAFTER (MONDAY ONWARD) THE 1523Z/30 WPC GRIDDED GUIDANCE WHICH AT TIMES IS BLENDED 50 50 WITH THE 12Z/30 MEXMOS. ALL THIS WAS EVENTUALLY CHECKED AGAINST THE 12Z/30 ECMWF THROUGH TUESDAY ONLY, WHEN WE MODIFIED THE NCEP-WPC GUIDANCE HIGHER BY SEVERAL DEGREES BOTH MONDAY AND TUESDAY! THE REMAINDER..WEDNESDAY AND BEYOND..OF THE 12Z/30 OPERATIONAL ECMWF DID NOT ARRIVE IN A TIMELY FASHION AND WAS NOT USED FOR THIS FORECAST. PRECIPITATION PROBABILITY GUIDANCE IS CHECKED AGAINST THE 09Z/30 SREF 3HRLY POPS FOR .01 THROUGH 00Z MONDAY AND THEREAFTER THE 12Z/30 GEFS 6HR POPS FOR 0.05. THE DAILIES BELOW... FRIDAY NIGHT...PERIODS OF RAIN DEVELOPING WESTWARD THROUGH NJ...POSSIBLY DURING THE EVENING TRICK OR TREAT TIME. CONFIDENCE ON FORECAST DETAILS IS AVERAGE. SATURDAY...COOLER THAN NORMAL AND BRISK WITH NORTHERLY GUSTS 20-30 MPH. RAIN PROBABLE AT TIMES SE PA THROUGH SOUTHERN-CENTRAL NJ AND PROBABLY SOUTH ONTO THE DELMARVA. 15Z SREF IS DRIER THAN I`D LIKE TO SEE FOR SATURDAY. SO THE COMBINATION OF THE LATE ARRIVING ECMWF AND SPREAD IN SOLUTIONS LOWERS MY CONFIDENCE ON SATURDAYS FORECAST TO ONLY AVERAGE. SUNDAY...WINDY AND MAYBE 5 DEGREES COLDER THAN NORMAL WITH NORTHWEST WINDS GUSTS 30-40 MPH. ISOLATED WIND ADVISORY CRITERIA POSSIBLE. THE GFS IS MORE ROBUST THAN THE 12Z ECMWF AND SO MY CONFIDENCE ON MAX WIND GUST IS BELOW AVERAGE. DIURNAL SC WITH PLENTIFUL MORNING SUNSHINE HIDING BEHIND INCREASING MIDDAY SC. THERE IS A SMALL CHANCE OF BUT AS YET UNMENTIONED...FOR AN AFTERNOON SPRINKLE WITH A SECONDARY TROUGH ALOFT PASSAGE. IF THE SPRINKLES MATERIALIZE...IT WOULD BE A SNOW SHOWER IN THE POCONOS. SUNDAY NIGHT...THE FROST FREEZE PORTION FOR OUR FORECAST AREA ENDS NOVEMBER 1 SO DESPITE THE FORECAST OF FROST OR FREEZING TEMPERATURES UNDER MOSTLY CLEAR SKIES AND LIGHT WINDS...A HEADLINE WILL NOT BE ISSUED. THERE IS A CHANCE OF MID LEVEL CLOUD COVER ARRIVING AROUND DAWN. MONDAY...DIMINISHED WIND AND MILDER. MID LVL CLOUD COVER. WEST WIND GUST 15 MPH. THE WPC GUIDANCE WAS RAISED BY 4 DEGREES DUE TO THE MUCH MILDER 12Z/30 ECMWF 2M TEMPS. TUESDAY...LOW CONFIDENCE ON HOW MUCH CLOUD COVER. THIS SHOULD BE A NICE DAY. ABOVE NORMAL TEMPS. WEDNESDAY...PROBABLY STILL NICE. MAYBE A SHOWER DEVELOPS LATE. ABOVE NORMAL TEMPS. THURSDAY...MAYBE A PERIOD OF SHOWERS OTHERWISE...THE NEXT TROUGH AND A COOL FRONT MAY BE MOVING INTO THE EASTERN USA. ABOVE NORMAL TEMPERATURES.
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&& .AVIATION /22Z THURSDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. CLOUD COVER IS MOVING ACROSS THE AREA FROM THE NORTHWEST WITH BASES FROM 3,500-5,000 FEET, VARYING FROM BROKEN TO SCATTERED FROM NORTHWEST TO SOUTHEAST. THIS CLOUD COVER WILL DISSIPATE AFTER SUNSET. WITH A DRIER AIRMASS MOVING IN, NO FOG IS EXPECTED TONIGHT. WINDS WILL BE FROM THE NORTH/NORTHWEST AT 5-10 KNOTS THIS AFTERNOON THEN BECOME LIGHT AND VARIABLE OVERNIGHT. ANOTHER VFR DAY IS EXPECTED FRIDAY WITH AN INCREASE IN MID-LEVEL CLOUDS AROUND 4,000 FEET IN THE AFTERNOON. AFTER 18Z SOME PATCHY DRIZZLE/SPRINKLES ARE POSSIBLE AT ACY. EXPECT ANY MVFR CEILINGS TO HOLD OFF UNTIL FRIDAY NIGHT IN ADVANCE OF THE NEXT RAIN MAKER. OUTLOOK... FRIDAY NIGHT...VFR CIGS MAY LOWER TO MVFR CIGS LATE. -SHRA SHOULD BE DEVELOPING OVER NJ POSSIBLY RESULTING IN MVFR VSBY AS WELL. SATURDAY...MVFR CIGS WITH POSSIBLE IFR CONDS IN SHOWERS ACROSS SE PA...THE DELMARVA...S AND CENTRAL NJ. NORTHERLY WINDS GUST 20-30 KT. SATURDAY NIGHT...CONDITIONS WILL SLOWLY IMPROVE FROM WEST TO EAST THROUGH THE NIGHT. GUSTY NNW WINDS SHOULD CONTINUE ESPECIALLY AT KACY. SUNDAY...MOSTLY VFR CONDITIONS. NW WIND GUSTS 23-33KT DIMINISHING AT NIGHT. CIGS NEAR 3500 FT IN THE EARLY AFTERNOON MAY YIELD AN ISOLATED SPRINKLE (EXCEPT FLURRY POCONOS?). MONDAY...VFR WITH BKN CIGS AOA 10000 FT. W-NW WIND GUSTING 15 KT. TUESDAY...VFR. && .MARINE... SEAS AND WINDS SHOULD REMAIN BELOW SCA CRITERIA THROUGH FRIDAY AFTERNOON. HOWEVER SOME WIND GUSTS CLOSE TO 20 KNOTS ARE POSSIBLE BY FRIDAY EVENING OFF THE DELAWARE COAST. OUTLOOK... HEADLINES HAVE BEEN ISSUED. TIMING OF THE ONSET OF GALE FORCE GUSTS IS STILL UNCERTAIN AND IF THIS GALE IS DELAYED TIL SATURDAY EVENING...I WANTED AN SCA TO PRECEDE. THE 12Z/30 GFS WW3 MODELED SEAS WERE INCREASED BY 2-3 FT SATURDAY THROUGH MIDDAY SUNDAY. FRIDAY NIGHT THROUGH SUNDAY...WINDS WILL BUILD INTO SCA CRITERIA, AND THEN GALES, WITH PEAK GUSTS NEAR 40KT POSSIBLE DURING THE DAY ON SATURDAY. GALE CONDITIONS COULD CONTINUE THROUGH MUCH OF THE DAY SUNDAY. SUNDAY NIGHT INTO MONDAY...WINDS SHOULD SUBSIDE BELOW SCA CRITERIA THROUGH THIS PERIOD THOUGH SCA SEAS MAY LINGER INTO EARLY MONDAY? TUESDAY...NO HEADLINE ANTICIPATED. && .TIDES/COASTAL FLOODING... AN ONSHORE COMPONENT OF THE BREEZY TO WINDY CONDITIONS ON SATURDAY WILL LEAD TO ELEVATED WATER LEVELS THIS WEEKEND. MINOR TIDAL FLOODING MAY OCCUR WITH THE HIGH TIDE CYCLES SATURDAY AND SATURDAY NIGHT. AT THIS TIME WE THINK IT UNLIKELY BUT WE STILL ARE MONITORING. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...GALE WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT FOR ANZ431-450>455. SMALL CRAFT ADVISORY FROM MIDNIGHT FRIDAY NIGHT TO 6 AM EDT SATURDAY FOR ANZ450>455. && $$ SYNOPSIS...DRAG NEAR TERM...GAINES SHORT TERM...GAINES LONG TERM...DRAG 527 CORRECTED TYPOS AVIATION...DRAG/GAINES MARINE...DRAG/GAINES TIDES/COASTAL FLOODING...

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