Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 182321 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 621 PM EST THU DEC 18 2014 .SYNOPSIS... LOW PRESSURE OVER ATLANTIC CANADA WILL TRACK TO THE NORTHEAST. HIGH PRESSURE OVER THE NORTHERN GREAT LAKES WILL MOVE INTO THE OHIO VALLEY OVERNIGHT. LOW PRESSURE IS EXPECTED TO FORM OVER THE GULF STATES FRIDAY NIGHT AND TRACK ACROSS GEORGIA SATURDAY. A COLD FRONT MAY MOVE THROUGH THE EASTERN SEABOARD ON CHRISTMAS EVE. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... NO BIG CHANGES WILL BE MADE WITH THIS ESTF. IN ADDITION TO THE STUBBORN STRATOCU, THERE WILL BE SOME MID LEVEL CLOUDINESS ASSOCIATED WITH A SHORT WAVE PASS ACROSS OUR CWA TONIGHT WHICH LOWERS THE CONFIDENCE ABOUT MIN TEMPS. SO FAR SO GOOD AS TEMPS AND DEW POINTS ARE CLOSE TO PREDICTED VALUES. CYCLONIC FLOW BTWN THE DEPARTING LOW OVR P.E.I. AND HIGH OVER LAKE SUPERIOR IS CAUSING ABUNDANT LO LVL MOISTURE TO BE BROUGHT INTO THE NERN U.S. AND W/ THIS CLD CVR ACROSS ERN PA/NJ-AWAY FM THE SHORE. PRES GRAD IN PLACE IS CAUSING WINDS TO GUST INTO THE M20S. 1026 SFC HIGH HAS MOVED INTO MI. CUTOFF LOW WL BE MOVG OVR NOVA SCOTIA TNGT. XPCTG WNWRLY WINDS TO WEAKEN. LOWS TNGT RANGING FM THE M20S IN THE POCONOS TO THE L30S NEAR WILDWOOD. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... FRIDAY SHOULD BE DOMINATED BY GREAT LAKES HIGH PRESSURE WHICH SHOULD YIELD PARTY CLOUDY SKIES. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... MID-LEVEL FLOW THE NEXT COUPLE OF DAYS IS RATHER FLAT THOUGH A CHANGE TO THAT PATTERN APPEARS LIKELY BY THE END OF THE WEEKEND. A DEEP TROUGH EMERGES ACROSS THE CENTRAL U.S. BY TUESDAY AS MULTIPLE PACIFIC NORTHWEST WAVES ROUND THE BASE OF THE TROUGH AND ACROSS OUR REGION...WE ARE HEADING FOR A VERY UNSETTLED PERIOD BY EARLY NEXT WEEK. FRIDAY NIGHT - SATURDAY...LOOKS DRY. FRIDAY SHOULD BE DOMINATED BY GREAT LAKES HIGH PRESSURE WHICH SHOULD YIELD PARTY CLOUDY SKIES. SATURDAY NIGHT AND SUNDAY...AN INVERTED TROUGH MAY THROW BACK SOME MOISTURE ACROSS THE AREA AS A WEAK WAVE OF LOW PRESSURE MOVES WELL OFFSHORE OF OUR REGION. ONLY HAVE SLIGHT CHANCE POPS ACROSS THE NORTHEASTERN PORTION OF THE CWA AS THAT LOOKS LIKE THE MOST FAVORABLE LOCATION FOR THE TONGUE TO MOISTURE TO REACH. GIVEN THE OVERNIGHT TIMING PRECIP COULD FALL AS RAIN SNOW MIX OR ALL SNOW. MONDAY - TUESDAY...LOW PRESSURE MOVES OFF THE CAROLINA COAST AND OUT TO SEA ON TUESDAY. THIS LOW WILL HELP LIFT A WARM FRONT ASSOCIATED WITH A LARGE AND DEVELOPING LOW PRESSURE SYSTEM OVER THE MIDDLE OF THE CONUS INTO THE AREA. ONSHORE FLOW AHEAD OF THE SYSTEM AND WARM AIR MOVING IN WITH THE FRONT WILL ALLOW FOR A WARMING LOW-LEVEL THERMAL PROFILE SO PRECIP SHOULD BE PRIMARILY LIQUID. MID-RANGE CHANCE POPS WILL PERSIST MONDAY...MONDAY NIGHT...AND TUESDAY. WEDNESDAY...STILL WATCHING A LARGE LOW PRESSURE FORM TO OUR WEST AND TRACK INTO THE GREAT LAKES REGION ON WEDNESDAY. THIS WOULD KEEP OUR REGION UNDER A WARMING THERMAL PROFILE WITH A LOT OF MOISTURE TO WORK WITH. WHAT IS INTERESTING WITH THE LATEST MODEL RUNS IS HOW THEY ARE SEEMINGLY WEAKENING THE PRIMARY LOW AS IT MOVES INTO THE LAKES ALLOWING FOR ANOTHER, STRONGER, PIECE OF PAC NW ENERGY TO PRODUCE CYCLOGENESIS ACROSS THE MID-ATLANTIC. IT APPEARS THAT CHRISTMAS EVE WL BE A DAY W/ MOISTURE, WINDS, AND POSSIBLY CONVECTION. LKLY POPS ARE IN THE FCST. THURSDAY...CHRISTMAS DAY - DEEP LAYER ZONAL FLOW WILL FILL IN ACROSS THE AREA. DRY CONDITIONS XPCTD AS THE COLD FRONT SHOULD BE E OF THE AREA. A DEEP STACKED LOW WILL BE OVER THE EASTERN GREAT LAKES. RIGHT NOW "COOL AND BRZY" COULD BE THE WX WORDS FOR THE DAY. && .AVIATION /23Z THURSDAY THROUGH TUESDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 00Z TAFS WILL BE VFR. TONIGHT...A VFR CIG IS FORECAST. FOR KACY AND KMIV THIS IS MAINLY DUE TO MID LEVEL CLOUDS. AT THE KPHL AIRPORTS, ITS A COMBINATION OF A STRATOCU CIG AROUND 4K AND THE MID LEVEL CLOUD DECK. AT KRDG AND KABE ITS MAINLY A STRATOCU DECK AT AROUND 3500 FEET. THERE WILL BE MVFR CIGS AT AIRPORTS FARTHER TO THE NORTHWEST AND MIGHT MAKE IT INTO THESE LATTER TERMINALS. WEST TO NORTHWEST WINDS SHOULD AVERAGE LESS THAN 10 KNOTS. FRIDAY...GOING MORE PESSIMISTICALLY WITH VFR CIGS AND EXPECTING A STRATOCU CIG TO EITHER PERSIST NORTHWEST TO TERMINALS, OR DEVELOP ELSEWHERE DURING THE DAY. MVFR CIGS POSSIBLE HIER TERRAIN AIRPORTS. NORTHWEST WINDS SHOULD BE SLIGHTLY LESS THAN TODAY WITH SUSTAINED SPEEDS AROUND 10 KNOTS AND PEAK GUSTS CLOSER TO 20 KNOTS. LATE IN THE DAY WE ARE PREDICTING THE GUSTS AND VFR CIGS SHOULD NO LONGER OCCUR. OUTLOOK... FRIDAY NIGHT - SATURDAY...VFR. NORTHWEST WINDS VEER TOWARDS THE NORTH-NORTHEAST BY SATURDAY. SUNDAY - MONDAY...SUB-VFR POSSIBLE WITH SCATTERED RAIN/SNOW SHOWERS. TUESDAY...VFR. && .MARINE... THE SMALL CRAFT ADVISORY NORTHERN WATERS WILL BE EXTENDED DEEPER INTO THIS EVENING AS MORE FREQUENT GUSTS TO 25 KTS ARE POSSIBLE, THE REST OF THE SMALL CRAFT ADVISORY WILL BE DROPPED. GUSTS NEAR OR ABOVE 20 KT WILL BE POSSIBLE THROUGH THE OVERNIGHT HOURS ELSEWHERE. OUTLOOK... FRIDAY...MOSTLY SUB-ADVISORY CONDITIONS ARE EXPECTED. SOME NORTHWEST WIND GUSTS COULD STILL BE IN THE 20 PLUS KNOT RANGE, THOUGH. CONFIDENCE: ABOVE AVERAGE. SATURDAY - SUNDAY...SUB-SCA EXPECTED FOR THE MOST PART. SEAS REMAIN AROUND 3 TO 4 FEET. CONFIDENCE: AVERAGE TO SLIGHTLY BELOW AVERAGE. MONDAY - TUESDAY...SCA CONDITIONS SHOULD PRESENT THEMSELVES LATER ON MONDAY UNDER A STRENGTHENING EASTERLY FLOW AND BUILDING SEAS. CONFIDENCE: AVERAGE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ450- 451. && $$ SYNOPSIS...GIGI/99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...GIGI/99 MARINE...GIGI/99

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