Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 260246 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 946 PM EST WED FEB 25 2015 .SYNOPSIS... A COLD FRONT WILL CONTINUE TO WEAKEN AND PUSH OUT TO SEA TONIGHT. A COASTAL LOW WILL MOVE TO OUR SOUTH AND EAST TONIGHT INTO THURSDAY. HIGH PRESSURE WILL BUILD ACROSS THE MID ATLANTIC LATE FRIDAY INTO EARLY SUNDAY. THE HIGH WILL BUILD OFFSHORE AHEAD OF A COLD FRONT THAT IS EXPECTED TO PASS THROUGH SUNDAY NIGHT INTO MONDAY. HIGH PRESSURE WILL BRIEFLY RETURN MONDAY NIGHT INTO TUESDAY, BEFORE RETREATING NORTHEASTWARD AS A SYSTEM APPROACHES FROM THE SOUTH. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... WITH THIS UPDATE WE ARE GOING TO UPGRADE SUSSEX COUNTY DELAWARE TO WARNINGS AND ADD A TIER OF ADVISORIES FARTHER TO THE NORTH. IN A VERY CONFLICTING WINTER THERE WAS CONFLICTED VERIFICATION THROUGH 00Z. BOTH THE GFS AND ECMWF VERIFIED BEST WITH THE PCPN MASS FIELDS (WRF-NMMB AND SREF MEAN WAS TOO FAR NORTHWEST). PROBLEM GOING FORWARD IS THAT THEY SPLIT WITH THE NORTHWESTERN EXTENT OF THE PCPN. LATEST 00Z WRF-NMMB HAD A SHIFT TO THE SE IN ITS HEAVIER PCPN AXIS TO THE SE AND THIS WOULD MAKE SENSE GIVEN ABOVE. RAP HAS BEEN PRETTY BULLISH WITH ITS PCPN THIS EVENING, BUT IT TOO IS VERIFYING TOO WET IN THE CAROLINAS. WHILE THIS ALL SEEMS TO POINT TO LESS, FORECAST SOUNDINGS ARE SHOWING MODERATE OMEGA WITHIN THE SNOW GROWTH AREA IN THE SOUTHEASTERN PART OF OUR CWA FOR A FEW HOURS ON THURSDAY MORNING. SO APPLYING A 15:1 RATIO EVEN TO THE DRIEST GFS SOLUTION WOULD GET SUSSEX COUNTY TO WARNING CRITERIA, WHICH WE UPGRADED. THE NEXT SLICE UPWARD WITHOUT CORROBORATION FROM THE HRRR AND THE 18Z CAN RGEM, WE LEFT AS ADVISORIES. WE ADDED A WINT WX ADVISORY FROM CECIL NEWD INTO BURLINGTON AND OCEAN MAINLY BECAUSE THE SNOW IS EXPECTED TO FALL DURING THE MORNING COMMUTE. THERE IS UNCERTAINTY AS MODELS ARE STRUGGLING WITH SFC DEW POINTS (THEY ARE DRIER THAN THEY ARE PREDICTING), BUT THERE REMAINS A DECENT NEG TILT SHORT WAVE WHICH DOES PASS THROUGH THE AREA. WITH CLOUDS ROLLING IN, WE GENERALLY UPPED TEMPERATURES BY A FEW DEGREES. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... SNOW SHOULD BE FALLING ACROSS THE SOUTHERN AREAS WITH A PUSH NORTHWARD THROUGH THE MORNING. THE MORNING COMMUTE IS LIKELY TO BE IMPACTED AND CAUTION WILL BE NEEDED ON THE AREA ROADWAYS. THERE WAS A SLIGHT NORTHWARD PUSH WITH THE 12Z MODEL GUIDANCE AND WE HAVE UPPED THE SNOW TOTALS ACROSS THE REGION, WITH THE HIGHEST AMOUNTS REMAINING ACROSS SOUTHERN DELAWARE. NORTH OF THE I-95 CORRIDOR, THE AIR REMAINS A BIT DRIER AND NOT EXPECTING MUCH, IF ANY, SNOW ACCUMULATION TO OCCUR. AREAS ALONG THE I-95 CORRIDOR WILL SEE AROUND AN INCH OR LESS WITH AMOUNTS INCREASING AS YOU HEAD TO THE SOUTH AND EAST. ACROSS SOUTHERN DELAWARE, EXPECT AROUND 3 TO 5 INCHES OF SNOW TO FALL, WITH HIGHEST AMOUNTS CLOSER TO THE MARYLAND BORDER. THERE IS SOME INDICATION IN SOME OF THE MODEL GUIDANCE THAT HIGHER AMOUNTS ARE POSSIBLE, ESPECIALLY ACROSS SOUTHERN DELAWARE, SOUTHERN EASTERN SHORE OF MARYLAND AND EXTREME SOUTHERN NEW JERSEY, AS QPF AMOUNTS ARE EDGING HIGHER WITH THE 12Z MODEL RUNS AND THIS WILL NEED TO BE WATCHED AS THIS SYSTEM DEVELOPS AND PUSHES NORTHWARD. A SLIGHT NORTHERLY PUSH TO THE CURRENT FORECAST TRACK WOULD INCREASE AMOUNTS, ESPECIALLY ACROSS THE SOUTH. TEMPERATURES WILL GENERALLY BE IN THE 20S ACROSS THE FORECAST AREA. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... ANY PRECIPITATION ASSOCIATED WITH THE STORM SYSTEM OVERNIGHT WEDNESDAY INTO THURSDAY MORNING SHOULD FULLY PULL AWAY FROM THE AREA BY THURSDAY EVENING. HOWEVER, AS WE MOVE INTO THE OVERNIGHT THURSDAY INTO THE EARLY PART OF FRIDAY, ANOTHER AREA OF LOW-MID LEVEL MOISTURE SLIDES ACROSS THE AREA WHILE A SHORT WAVE APPROACHES FROM HE WEST. IT`S POSSIBLE THERE MAY BE JUST ENOUGH LIFT AND MOISTURE COMBINED TO CREATE AN AREA OF LIGHT SNOW SHOWERS ACROSS A PORTION OF THE AREA. THIS MOISTURE WILL PULL AWAY FROM THE AREA DURING THE DAY FRIDAY AND ANY SHOWER ACTIVITY SHOULD END BY THE AFTERNOON. AS WE MOVE INTO FRIDAY NIGHT, AND CONTINUING THROUGH SATURDAY AND SATURDAY NIGHT, HIGH PRESSURE BUILDS ACROSS THE EAST COAST. THIS WILL PROVIDE TRANQUIL WEATHER ACROSS THE AREA. THE ONLY PROBLEM WITH THIS TRANQUIL WEATHER IS TEMPERATURES WILL REMAIN WELL BELOW NORMAL. THE HIGH BUILDS OFFSHORE DURING THE DAY SUNDAY, ALLOWING FOR RETURN FLOW TO DEVELOP. MOISTURE INCREASES AHEAD OF AN APPROACHING COLD FRONT. THE FRONT DOES NOT ACTUALLY MOVE INTO THE AREA UNTIL OVERNIGHT SUNDAY INTO MONDAY. THERE COULD BE A FEW SHOWERS DEVELOPING TO OUR WEST AS EARLY AS SUNDAY AFTERNOON, BUT THE MAIN AREA OF PRECIPITATION IS EXPECTED OVERNIGHT SUNDAY INTO MONDAY MORNING IN ASSOCIATION WITH THE FRONTAL PASSAGE. PTYPES COULD BECOME A CONCERN FOR PORTIONS OF THE AREA, STARTING AS SNOW, THEN CHANGING TO A WINTRY MIX AND/OR RAIN FOR A PORTION OF THE AREA LATER INTO SUNDAY NIGHT/MONDAY MORNING. HIGH PRESSURE AND PRECIPITATION FREE FORECAST BRIEFLY BUILDS INTO THE MONDAY NIGHT INTO TUESDAY. HOWEVER, BY LATE TUESDAY THERE COULD BE SOME LIGHT PRECIPITATION MOVING INTO THE AREA AHEAD OF THE NEXT STORM SYSTEM APPROACHING FROM THE SOUTH. THE GFS AND ECMWF SHOW AN AREA OF LOW PRESSURE LIFTING THROUGH THE MID-WEST TUESDAY NIGHT INTO WEDNESDAY, ALTHOUGH THERE IS SOME SLIGHT TIMING DIFFERENCES, AND LIFTING A COMPLEX FRONTAL SYSTEM INTO OUR AREA. PTYPES COULD AGAIN BECOME A PROBLEM ACROSS THE AREA, WITH THE PRECIPITATION POSSIBLY STARTING AS SNOW, THEN CHANGING TO A WINTRY MIX AND/OR RAIN FOR A PORTION OF THE AREA OVERNIGHT TUESDAY INTO WEDNESDAY MORNING. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. 00Z TAFS VFR FOR THIS EVENING AND MOST OF OVERNIGHT GOING DOWN TO IFR KPHL METRO AREA SOUTHEAST THURSDAY MORNING, MIGHT REMAIN MVFR DUE TO CIGS THURSDAY AFTERNOON. THIS EVENING...VFR WITH HIGH LEVEL CIG MOVING IN. WIND DIRECTION AN AVERAGE FOR FORECAST PERIOD AS THEY WILL BE VEERING TO THE NORTH. SPEEDS LIGHT. OVERNIGHT...KRDG AND KABE AS WELL AS PHL METRO AIRPORTS REMAINING VFR WITH A LOWERING CIG. NORTH TO NORTHEAST WINDS INCREASING TO AROUND 10 KTS, LIGHTER FAR NORTHWEST TERMINALS. AT KACY AND KMIV, BECOMING IFR (VSBYS) LATE IN SNOW. THERE IS A CHANCE A MVFR CIG MIGHT DEVELOP PRIOR. NORTHNORTHEAST WINDS INCREASING TO 10 TO 15 KNOTS WITH SOME HIGHER GUSTS. THURSDAY MORNING...KACY AND KMIV IFR (VSBYS MOSTLY) IN SNOW. IMPROVING LATE. NORTHNORTHEAST WINDS AVERAGING 10 TO 15 KNOTS WITH SOME GUSTS 20 TO 25 KNOTS. KPHL METRO AIRPORTS BECOMING MVFR TO IFR IN SNOW. CIGS OR VSBYS CAUSE. REGION WILL BE NEAR NORTHWEST EDGE OF STEADY SNOW, SO CONFIDENCE IS MODERATE. NORTHNORTHEAST WINDS 10 TO 15 KNOTS. KABE AND KRDG SHOULD REMAIN MAINLY VFR IN SNOW FLURRIES. THURSDAY AFTERNOON...PREVAILING MVFR CONDITIONS DUE TO CIGS. VSBY REDUCING SNOW SHOULD BE DONE. NORTH TO NORTHEAST WINDS BECOMING LIGHTER WITH AVERAGE SPEEDS CLOSE TO 10 KNOTS. THURSDAY EVENING...KPHL TAF BECOMING VFR WITH A HIGHER BASED CIG. OUTLOOK... THURSDAY NIGHT-FRIDAY...MOSTLY VFR WITH MVFR CIGS POSSIBLE. FRIDAY NIGHT-SUNDAY...VFR. LIGHT NORTHWEST-WEST WINDS, BECOMING SOUTHWEST SUNDAY. SUNDAY NIGHT-MONDAY...LOWERING CONDITIONS WITH MVFR/IFR DEVELOPING. A WINTRY MIX LIKELY ACROSS PORTIONS OF THE AREA, BECOMING RAIN ON MONDAY. && .MARINE... THE SMALL CRAFT ADVISORY ON THE NORTHERN OCEAN WATERS HAS BEEN EXTENDED THROUGH 22Z THURSDAY. A SMALL CRAFT ADVISORY HAS BEEN RAISED ON THE LOWER DELAWARE BAY AND THE SOUTHERN OCEAN WATERS STARTING AT 09Z THURSDAY AND ENDING AT 22Z THURSDAY. WESTERLY WINDS WILL VEER TO THE NORTHEAST OVERNIGHT AND BECOME GUSTY THROUGH THE DAY ON THURSDAY. IN ADDITION, SEAS WILL RISE IN EXCESS OF 5 FEET. FREEZING SPRAY WILL BE POSSIBLE THROUGH THURSDAY. OUTLOOK... THURSDAY NIGHT-FRIDAY NIGHT...SUB SMALL CRAFT ADVISORY LEVELS EXPECTED ACROSS THE WATERS. SEAS MAY REMAIN CLOSE TO 4 FEET. SATURDAY-SUNDAY...SUB SMALL CRAFT ADVISORY CONDITIONS CONTINUE AS HIGH PRESSURE BUILDS ACROSS THE WATERS. SUNDAY NIGHT-MONDAY NIGHT...SMALL CRAFT ADVISORY CONDITIONS LIKELY DEVELOPING AS A FRONTAL BOUNDARY APPROACHES AND CROSSES THE WATERS. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...WINTER WEATHER ADVISORY FROM 6 AM TO 1 PM EST THURSDAY FOR NJZ016>020-026-027. WINTER WEATHER ADVISORY FROM 4 AM TO 1 PM EST THURSDAY FOR NJZ021>025. DE...WINTER WEATHER ADVISORY FROM 6 AM TO 1 PM EST THURSDAY FOR DEZ001. WINTER STORM WARNING FROM 3 AM TO 1 PM EST THURSDAY FOR DEZ003- 004. WINTER WEATHER ADVISORY FROM 4 AM TO 1 PM EST THURSDAY FOR DEZ002. MD...WINTER WEATHER ADVISORY FROM 6 AM TO 1 PM EST THURSDAY FOR MDZ008. WINTER WEATHER ADVISORY FROM 4 AM TO 1 PM EST THURSDAY FOR MDZ012-015-019-020. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 5 PM EST THURSDAY FOR ANZ431- 452>455. SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ450-451. && $$ SYNOPSIS...ROBERTSON NEAR TERM...GIGI SHORT TERM...MEOLA LONG TERM...ROBERTSON AVIATION...ROBERTSON/MEOLA MARINE...ROBERTSON/MEOLA

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