Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 200235 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 935 PM EST WED NOV 19 2014 .SYNOPSIS... HIGH PRESSURE SLIDES OFFSHORE TONIGHT AND IS FOLLOWED BY A COLD FRONTAL PASSAGE ON THURSDAY. BEHIND THIS FRONT, A STRONGER HIGH PRESSURE SYSTEM WILL MOVE IN FROM THE WEST ON FRIDAY, AND CREST OVER THE REGION ON SATURDAY BEFORE MOVING OFFSHORE ON SUNDAY. MEANWHILE, LOW PRESSURE WILL DEVELOP ACROSS THE INTER-MOUNTAIN WEST, AND TRACK NORTHEASTWARD TO LAKE MICHIGAN. THIS LOW WILL BRING A COLD FRONT THROUGH THE REGION EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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MID LEVEL CLOUDS WERE DEVELOPING OVERHEAD IN THE WEAK WARM ADVECTION IN ADVANCE OF AN APPROACHING COLD FRONT. THE CLOUDS AND THE SOUTH TO SOUTHWEST SURFACE FLOW SHOULD PREVENT TEMPERATURES FROM DROPPING MUCH OVERNIGHT. WE CONTINUE TO EXPECT MINIMUM TEMPERATURES TO BE MOSTLY IN THE 20S. THERE REMAINS A CHANCE FOR SNOW FLURRIES IN THE ELEVATED TERRAIN OF THE POCONOS AND FAR NORTHERN NEW JERSEY OVERNIGHT.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
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SOUTHERLY FLOW WILL GIVE WAY ONCE AGAIN TO WESTERLY BEHIND THE COLD FRONT. STILL VERY DRY NO PRECIPITATION EXPECTED FROM THIS WITH THE EXCEPTION OF A FLURRY FOR THE POCONOS AND MORNING CLOUDS. THE MAIN CHALLENGE WILL BE THE FRONTAL TIMING AND TEMPERATURES. THE ECMWF IS SLOWER AND WARMER GIVING PHL A GOOD SHOT TO GET WELL INTO THE 40`S. HOWEVER THE GFS IS FASTER WITH PHL BARELY HITTING 40. FRONTAL PASSAGE NW OF PHL SHOULD OCCUR IN THE MORNING, LIMITING THE MODEL SPREAD FOR TEMPERATURES IN THIS REGION. A SLOWER FRONTAL PASSAGE ALLOWS FOR COASTAL AREAS TO SEE MORE SOUTHERLY FLOW AND MAKE A RUN AT 50. WENT A COUPLE OF DEGREES BELOW MAV/MET NORTHWEST GIVEN NW FLOW AND WENT ABOVE MAV/MET ALONG THE COAST DUE TO THE SOUTHERLY FLOW.
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&& .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
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HIGHLIGHTS... * TEMPERATURES WELL BELOW NORMAL FRIDAY W/SNOW SHOWERS POSSIBLE IN THE POCONOS * CHANCE OF RAIN LATE SUNDAY INTO EARLY NEXT WEEK W/TEMPERATURES ABOVE NORMAL * TEMPERATURES PROJECTED TO RETURN TO SEASONABLE LEVELS MID-WEEK DETAILS... A PATTERN CHANGE IS UNDERWAY AS THE PERSISTENT BLOCKING PATTERN ALONG THE WEST COAST OF NOAM /POSITIVE HEIGHT ANOMALIES/ BREAKS DOWN...ALLOWING A VIGOROUS S/WV TO MOVE INTO THE FOUR CORNERS REGION ON SATURDAY...LEADING TO STRONG DOWNSTREAM HEIGHT RISES ACROSS THE E CONUS, W/THE MID-LEVEL TROUGH GRADUALLY LIFTING TO THE NORTHEAST ON FRIDAY AND RIDGING TAKING ITS PLACE BY MONDAY. THIS WILL LEAD TO A WARMING TREND...WITH MAXIMUM TEMPERATURES WELL BELOW NORMAL ON FRIDAY MODERATING TO ABOVE NORMAL LEVELS BY MONDAY. THE GFS...ECMWF AND THEIR RESPECTIVE ENSEMBLES ARE IN GENERAL AGREEMENT ON TAKING THE SOUTHERN STREAM S/WV INTO THE FOUR- CORNERS REGION ON SATURDAY...BUT DIFFER ON THE STRENGTH OF THE NORTHERN STREAM S/WV COMING ASHORE IN THE PACIFIC NORTHWEST AT THAT TIME. THIS HAS IMPLICATIONS FOR THE DEGREE OF DOWNSTREAM PHASING OVER THE UPPER MS VALLEY ON SUNDAY AND THE EVOLUTION OF THE RESULTANT STORM SYSTEM. THE MODELS AGREE ON A STORM TRACK OVER THE MICHIGAN PENINSULA...BUT THE WEAKER NORTHERN STREAM SHORTWAVE HAS LEAD TO A FASTER SOLUTION BY 24-HOURS...W/THE LOW NOW PROGGED OVER THE MICHIGAN PENINSULA AT 12Z MONDAY. BUT AT D+5 IT/S TOUGH TO SPECULATE IF THIS TRACK AND TIMING WILL HOLD. NEVERTHELESS...THE PATTERN FAVORS A STORM TRACK TO THE WEST OF THE APPALACHIANS AS WELL AS WARMER AIR MOVING INTO THE E CONUS... BUT UNCERTAINTY IN THE TRACK AND STRENGTH OF THIS STORM SYSTEM TRANSLATES INTO UNCERTAINTY IN THE TEMPERATURE FORECAST SUNDAY AND BEYOND. LOOKING AHEAD TO TUESDAY AND WEDNESDAY...A FRONTAL PASSAGE DURING THIS TIME FRAME LOOKS TO DELIVER A REINFORCING SHOT OF COLD AIR...WHILE CYCLOGENSIS MAY TAKE PLACE INVOF THE EAST COAST, WHICH BEARS WATCHING AS THE NAO IS PROJECTED TO GO NEGATIVE.
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&& .AVIATION /03Z THURSDAY THROUGH MONDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. CEILINGS MAY LOWER INTO THE 4500 TO 5500 FOOT RANGE FOR A TIME LATE TONIGHT INTO THURSDAY MORNING AT KRDG AND KABE. CEILINGS SHOULD REMAIN AT OR ABOVE 8000 FEET OVER OUR REMAINING TAF SITES. THE CLOUD COVER SHOULD BECOME SCATTERED FOR LATE THURSDAY MORNING AND THURSDAY AFTERNOON. A SOUTHERLY WIND AT 5 TO 10 KNOTS THIS EVENING SHOULD VEER TO THE SOUTHWEST AND WEST OVERNIGHT. A WEST WIND AROUND 8 TO 12 KNOTS WITH GUSTS NEAR 20 KNOTS IS ANTICIPATED FOR THURSDAY. OUTLOOK... FRIDAY...VFR. NORTHWEST WINDS MAY GUST TO 25 KNOTS DURING THE LATE MORNING THRU EARLY AFTERNOON HOURS. SATURDAY...VFR. SUNDAY AND MONDAY...MVFR POSSIBLE IN LOW CEILINGS AND -SHRA ESPECIALLY LATE SUNDAY AND PARTICULARLY ON MONDAY.
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&& .MARINE... SEAS AND WINDS SHOULD INCREASE THIS EVENING. THE ENVIRONMENT WILL BE FAVORABLE FOR SOME SOUTHWEST GALE FORCE WIND GUSTS AROUND 35 KNOTS ON THE OCEAN WATERS FROM 04-12Z THURSDAY. A GALE WARNING IS IN EFFECT. THE GALE GUSTS MAY NOT BE SUSTAINED THROUGH THIS WHOLE PERIOD BUT MAY BE MORE OF A INTERMITTENT VARIETY. SCA CONDITIONS LIKELY WILL CONTINUE THROUGHOUT THE DAY THURSDAY WITH NORTHWESTERLY WINDS. OUTLOOK... FRIDAY...SCA WINDS AND SEAS LIKELY THURSDAY NIGHT AND FRIDAY... SLOWLY SUBSIDING TO SUB-SCA CONDITIONS FRIDAY NIGHT. SATURDAY AND SUNDAY...SUB-SCA CONDITIONS ARE ANTICIPATED ATTM. MONDAY...A GALE WARNING MAY BE NEEDED. && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...GALE WARNING UNTIL 7 AM EST THURSDAY FOR ANZ450>455. SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ430-431.
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&& $$ SYNOPSIS...FRANCK NEAR TERM...IOVINO SHORT TERM...GAINES LONG TERM...FRANCK AVIATION...FRANCK/IOVINO MARINE...FRANCK/GAINES

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