Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 161422 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1022 AM EDT WED APR 16 2014 .SYNOPSIS... A STRONG COLD FRONTAL SYSTEM WILL CONTINUE MOVING OFFSHORE TODAY WITH HIGH PRESSURE BUILDING INTO THE REGION FOR THIS AFTERNOON AND TONIGHT. THE HIGH PRESSURE SYSTEM WILL MOVE INTO NEW ENGLAND ON THURSDAY. BY FRIDAY ANOTHER COLD FRONTAL BOUNDARY WILL APPROACH THE REGION MOVING THROUGH THE REGION ON SATURDAY. HIGH PRESSURE WILL ONCE AGAIN MOVE BACK INTO NEW ENGLAND FOR SUNDAY AND MONDAY AS A LOW PRESSURE SYSTEM DEVELOPS IN THE PLAINS. THIS LOW PRESSURE SYSTEM WILL BRING A WARM FRONT THROUGH THE REGION MONDAY NIGHT AND A COLD FRONTAL BOUNDARY THROUGH THE REGION TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE CURRENT FORECAST SEEMS TO BE ON TRACK SO ONLY MINOR ADJUSTMENTS WERE MADE TO TEMPS AND WINDS. GUSTY NW WINDS ARE CONTINUING TO BLOW THIS MORNING CAUSING WIND CHILLS IN THE 20S IN SPITE OF AMPLE SUNSHINE. THE MORNING VISIBLE SATELLITE IMAGERY SHOWS SOME PATCHES OF SNOW COVER OVER PARTS OF EASTERN PA AND NJ. ALL RAIN, SLEET, AND SNOW HAS MOVED OFFSHORE THIS MORNING AND WE ARE LEFT WITH PARTLY TO MOSTLY CLOUDY SKIES EARLY THIS MORNING. THE ONLY EXCEPTION TO THIS IS SOME LAKE EFFECT SNOW SHOWERS/FLURRIES ACROSS THE POCONOS WITHIN THE NORTHEAST FLOW. THESE COULD CONTINUE FOR A FEW HOURS, BUT AS THE WINDS BEGIN TO SWING MORE NORTH THEN NORTHEAST, THE FLOW OFF THE LAKES WILL GET CUT OFF AND END THE SNOW SHOWER CHANCE. WE WILL KEEP ISOLATED SNOW SHOWERS FOR A FEW HOURS ACROSS THE POCONOS THIS MORNING. HIGH PRESSURE WILL BUILD ACROSS THE AREA TODAY ALLOWING DRY AIR TO SETTLE ACROSS THE AREA THROUGH THE DAY. WINDS WILL BE GUSTY THROUGH THE MORNING HOURS INTO THE EARLY AFTERNOON, BUT AS THE HIGH BUILDS OVER THE AREA, THE WINDS WILL LIGHTEN AND THE GUSTS SHOULD DROP OFF. TEMPERATURES TODAY WILL NOT BE ABLE TO WARM MUCH AS 925 MB TEMPERATURES TOP OUT AROUND -1 TO -2 DEGREES CELSIUS. MOS NUMBERS WERE FAIRLY CLOSE, SO WE USED A BLEND OF MAV/MET MOS, MOS GUIDE, AND ECMWF GRIDS. THIS YIELDS AFTERNOON HIGHS WELL BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... HIGH PRESSURE WILL BUILD ACROSS NEW ENGLAND OVERNIGHT TONIGHT INTO THURSDAY MORNING, BUT STILL EXTEND SOUTHWARD ACROSS OUR AREA. THIS WILL KEEP DRY WEATHER ACROSS THE AREA THROUGH TONIGHT AND THURSDAY MORNING. MOS NUMBERS WERE FAIRLY CLOSE, SO WE USED A BLEND OF MAV/MET MOS AND MOS GUIDE. THIS YIELDS OVERNIGHT LOWS WELL BELOW NORMAL ONCE AGAIN. THE FREEZE WATCH WILL REMAIN IN PLACE AS TEMPERATURES ARE EXPECTED TO DROP TO OR BELOW FREEZING BY THURSDAY MORNING. WE WILL KEEP FROST IN THE GRIDS AS WINDS WILL BE LIGHTER THAN LAST NIGHT/THIS MORNING, BUT THERE MAY STILL BE ENOUGH OF A BREEZE IN MOST PLACES TO PREVENT WIDESPREAD FROST FROM OCCURRING. && .LONG TERM /THURSDAY THROUGH TUESDAY/... THURSDAY AND THURSDAY NIGHT: LOOKS TO BE A RELATIVELY QUIET PERIOD UNDER NORTHEASTERLY FLOW FROM THE FRONTAL BOUNDARY OFFSHORE AND HIGH PRESSURE TO OUR NORTH. THE ONE CONCERN MAY BE SOME LOW CLOUDS AND DRIZZLE THAT ADVECT IN FROM THE OCEAN ALONG THE IMMEDIATE COAST. FOR NOW LEFT IT LESS THAN A SLIGHT CHANCE FOR THE FAR SE PORTIONS OF THE CWA IN LINE WITH THE SREF AND 00Z NAM/GFS. THINKING THE FROST THREAT MAY BE MORE LIMITED THIS PERIOD DUE TO SEVERAL FACTORS SUCH AS CLOUD COVER AND SOME WIND WITH SLIGHTLY WARMER TEMPERATURES. TOOK FROST OUT OF THE GRIDS IN THIS TIMEFRAME THOUGH SOME ISOLATED FROST CAN NOT BE TOTALLY RULED OUT. THINK ONCE AGAIN THE RAW MODELED TWO METER TEMPERATURES WILL BE TO COOL WITH THE 850 MB TEMPS OVER 0C. WENT CLOSE TO MAV/MET GUIDANCE FOR TEMPERATURES DURING THE DAY THEN WENT SLIGHTLY WARMER THAN MAV/MET AT NIGHT DUE TO CLOUDS. FRIDAY THROUGH SATURDAY NIGHT: LOW CLOUDS AND SOME SPOTTY SHOWERS/ DRIZZLE MAY STILL ADVECT IN FOR COASTAL REGIONS ON FRIDAY GOING MORE IN LINE WITH THE NAM/GFS AND SREF. THOUGH CONFIDENCE ON THE EXTENT ON ANY POTENTIAL LOW CLOUDS AND DRIZZLE IS LOWER THAN IDEAL. THIS SHOULD BREAK UP BY FRIDAY NIGHT ALONG THE COAST WITH INLAND SECTIONS REMAINING PARTLY CLOUDY. IT APPEARS THAT A FRONTAL BOUNDARY WILL MOVE FROM THE GREAT LAKES THROUGH THE REGION AS A LOW PRESSURE SYSTEM TRACKS ALONG THE SOUTHEAST COAST STAYING SEPARATE, PREVENTING A LARGER IMPACTING EVENT. MOISTURE AHEAD OF THE FRONTAL PASSAGE ON SATURDAY LOOKS LIMITED SO ONLY A FEW HUNDREDTHS FOR QPF. PRETTY TIGHT SPREAD AMONG MODELS AND MEX GUIDANCE WITH TEMPERATURES IN THESE PERIODS. SUNDAY AND SUNDAY NIGHT: LOOKS LIKE A GOOD WEATHER DAY ACROSS THE REGION. WITH PLENTIFUL SUNSHINE WENT MORE TOWARD MEX/WPC GUIDANCE ON TEMPERATURES. MONDAY THROUGH TUESDAY NIGHT: NEXT SYSTEM WILL BE A COLD FRONT APPROACHING FROM THE WEST BY MONDAY NIGHT WILL INCLUDE A CHANCE OF SHOWERS FROM MONDAY NIGHT THROUGH TUESDAY NIGHT. WENT MORE IN LINE WITH THE 00Z GFS IN THIS PERIOD AS THE NEW 00Z ECMWF HAS A ANOMALOUS CUT-OFF LOW OVER THE SOUTHEAST UNITED STATES WHICH ACTS A BLOCK FOR THE FRONT. DID GO LOWER THAN WPC GUIDANCE FOR TEMPERATURES ON TUESDAY GIVEN POTENTIAL RAINFALL. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. GUSTY NORTHWEST WINDS WILL DIMINISH THROUGH THE DAY AS HIGH PRESSURE BUILDS ACROSS THE AREA. WINDS WILL BECOME MORE NORTHEAST LATER THIS EVENING AND OVERNIGHT AS HIGH PRESSURE BUILDS ACROSS NEW ENGLAND. OUTLOOK... THURSDAY THROUGH FRIDAY NIGHT... MAINLY VFR, SOME SCATTERED LOW CEILINGS THURSDAY NIGHT AND FRIDAY MORNING SOUTHEAST OF KPHL. SATURDAY: MAINLY VFR, POSSIBLE BRIEF PERIODS OF MVFR IN SCATTERED SHOWERS. SATURDAY NIGHT AND SUNDAY: VFR. && .MARINE... ALTHOUGH STILL GUSTY...WINDS HAVE DIMINISHED SOMEWHAT OVER THE FORECAST WATERS AS OF MID MORNING. THEREFORE THE GALE WARNINGS WILL BE LOWERED AT 1000 AM AND REPLACED BY A SMALL CRAFT ADVISORY. WINDS ARE EXPECTED TO DIMINISH BELOW SCA CRITERIA BY LATE AFTERNOON...HOWEVER SEAS WILL LIKELY REMAIN AT OR NEAR SCA LEVELS. SO THE SCA FOR COASTAL WATERS GOES THROUGH TONIGHT AND WILL LIKELY NEED TO BE EXTENDED BEYOND THAT. OTHERWISE...WINDS WILL REMAIN GUSTY ACROSS THE WATERS UNTIL HIGH PRESSURE BUILDS ACROSS THE AREA AND HELPS DIMINISH THE WINDS. HOWEVER, WINDS MAY REMAIN GUSTY AROUND 15-20 KNOTS THROUGH TONIGHT. SEAS ARE EXPECTED TO SUBSIDE TO AROUND 4 FEET LATER TODAY INTO THIS EVENING, BUT SHOULD BUILD AGAIN OVERNIGHT AS A NORTHEAST FETCH TAKES PLACE AND WILL LIKELY INCREASE SEAS ONCE AGAIN TO 4-6 FEET. OUTLOOK... THURSDAY THROUGH FRIDAY NIGHT: SCA SEAS THROUGHOUT THE PERIOD ON THE OCEAN AND SOME SCA GUSTS LIKELY THURSDAY. SATURDAY AND SUNDAY: SUB SCA SEAS AND WINDS. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR PAZ060-070-101>104-106. NJ...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR NJZ012-013-015>023-027. DE...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR DEZ001>003. MD...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR MDZ008-012-015-019-020. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR ANZ450>455. SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ430- 431. && $$ SYNOPSIS...GAINES NEAR TERM...AMC SHORT TERM...ROBERTSON LONG TERM...GAINES AVIATION...GAINES/ROBERTSON MARINE...AMC/GAINES

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