Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 270004 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 804 PM EDT TUE APR 26 2016 .SYNOPSIS... A COLD FRONT WILL PUSH SOUTH OF OUR AREA THROUGH TONIGHT AND WEDNESDAY MORNING AND THEN STALL. LOW PRESSURE WILL TRACK ALONG THIS FRONT TO OUR SOUTH THURSDAY INTO FRIDAY. HIGH PRESSURE CENTERED NEAR HUDSON BAY CANADA FRIDAY INTO SATURDAY WILL BUILD DOWN INTO OUR AREA THROUGH MUCH OF SUNDAY. LOW PRESSURE THOUGH IN THE OHIO VALLEY MONDAY SLOWLY MOVES CLOSER TO OUR AREA TUESDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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8 PM: SVR TSTM WATCH CANCELLED DELMARVA. CLEANING UP REMAINDER FCST NEXT 90 MIN. 630 PM ESTF: BASICALLY SINCE 4P HAVE BEEN TRIMMING WATCH, MONITORING RADAR FOR SVR AND UPDATING TAFS. LAST GASP SHOWERS/ISO THUNDERSTORM NOW MARCHING THROUGH PHL AND MORE WATCH TRIM BY 655P. IF YOU HAVE ANY WIND DAMAGE REPORTS, PLS RELAY TO THE NWS. THANK YOU. HAVE HAD A FEW GUSTS 45 TO 60 MPH AND A BUNCH OF SMALL HAIL REPORTS. THE MESH HAS BEEN WORKING WELL. COOL FRONT AND BACKDOOR MARITIME FRONT CONT TO EDGE SOUTH AND SHOWERS WILL ALSO DEVELOP SOUTH BUT BE ON THE WANE MOST OF THE AREA AT SUNSET EXCEPT MAYBE DELMARVA.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... THE COLD FRONT IS EXPECTED TO DECELERATE AS IT MOVES SOUTHWARD INTO SRN VA AND NC ON WEDNESDAY. MEANWHILE, HIGH PRESSURE CENTERED NEAR THE CANADIAN NORTHWEST PASSAGES WILL BUILD SEWD INTO THE NORTHEAST STATES. THE LATEST GUIDANCE SHOWS DRIER AIR WITH THIS HIGH ADVECTING SOUTH INTO THE LEHIGH VALLEY AND NW NJ DURING THE MORNING BUT STRUGGLE TO ADVANCE FARTHER TO THE SOUTH DURING THE AFTERNOON. THIS APPEARS A RESULT OF THE WINDS ACROSS SE PA/S NJ/DELMARVA REMAINING VEERED OUT OF THE NE. FORECAST SOUNDINGS ACROSS THE SRN HALF OF THE CWA, ESPECIALLY FROM THE 12Z NAM, INDICATE MOISTURE WILL REMAIN TRAPPED UNDERNEATH THE BOUNDARY LAYER DUE TO ONSHORE FLOW OFF THE OCEAN. THE MARINE STRATOCU WILL BE STUBBORN TO ERODE THE FARTHER SOUTH YOU GO. HIGHS RANGE FROM THE MU50S IN THE DELMARVA AND COASTAL NJ TO LM60S IN E PA AND IN C/NW NJ. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... THE SYNOPTIC PATTERN IS FORECAST TO BE COMPRISED OF A STRONG CLOSED LOW NEAR THE CANADIAN MARITIMES WEDNESDAY NIGHT AND THURSDAY THAT THEN SHIFTS EASTWARD. THIS ALLOWS CYCLONIC FLOW TO OCCUR ACROSS OUR REGION FOR A TIME. THERE ARE SOME POCKETS OF ENERGY FORECAST TO EVOLVE AROUND THIS LARGE TROUGH, ALLOWING LOW PRESSURE TO TRACK ALONG A STALLED FRONTAL BOUNDARY TO OUR SOUTH THURSDAY THEN ANOTHER ONE EARLY NEXT WEEK. THIS WILL LEAD TO SOME UNSETTLED WEATHER AT TIMES, MOSTLY ON THURSDAY AND THEN AGAIN EARLY NEXT WEEK. THE AMOUNT OF PRECIPITATION AND CLOUD COVER WILL IMPACT THE TEMPERATURES, ESPECIALLY GIVEN THROUGH SUNDAY STRONG HIGH PRESSURE IS ANCHORED WELL TO OUR NORTH. WE USED A MODEL/CONTINUITY BLEND THROUGH FRIDAY, THEN BLENDED IN THE 12Z WPC GUIDANCE THEREAFTER. SOME ADJUSTMENTS WERE THEN MADE FOLLOWING ADDITIONAL COLLABORATION WITH OUR NEIGHBORING OFFICES. FOR WEDNESDAY NIGHT AND THURSDAY...A POTENT CLOSED LOW CENTERED NEAR THE CANADIAN MARITIMES WILL RESULT IN CYCLONIC FLOW ACROSS THE AREA. A STALLED FRONT TO OUR SOUTH WILL CONTINUE WITH ENERGY TRAVERSING IT, WITH THE MAIN ENERGY BACK INTO THE PLAINS. SURFACE HIGH PRESSURE TRIES TO BUILD DOWN INTO OUR AREA AT FIRST, HOWEVER A LEAD IMPULSE WILL DRIVE WAA AND OVERRUNNING INTO OUR AREA DURING THURSDAY. HOWEVER, THERE IS SOME UNCERTAINTY ON THE NORTHERN EXTENT AND ALSO COVERAGE OF THE SHOWERS ASSOCIATED WITH THIS GIVEN POTENTIALLY MUCH DRIER AIR ADVECTING SOUTHWARD. LOOKS LIKE THE HIGHEST CHCS FOR SHOWERS IS IN THE SOUTHERN HALF OF THE AREA AND THIS IS WHERE THE HIGHEST POPS ARE CURRENTLY PLACED. GIVEN A NORTHEASTERLY LOW- LEVEL FLOW AND THE PROSPECTS FOR A DECENT AMOUNT OF CLOUD COVER, WE ARE ANTICIPATING THURSDAY TO BE ON THE COOL SIDE. FOR FRIDAY THROUGH SUNDAY...SURFACE LOW FEATURE TO OUR SOUTH OVERALL SHOULD BE SHIFTING OFFSHORE TO START FRIDAY. AS ADDITIONAL ENERGY AMPLIFIES ACROSS THE PLAINS INTO SUNDAY, STRONG AND EXPANSIVE HIGH PRESSURE AT THE SURFACE CENTERED NEAR HUDSON BAY WILL WEDGE DOWN INTO OUR AREA ESPECIALLY SATURDAY AND MUCH OF SUNDAY. THIS WILL RESULT IN NORTHEASTERLY FLOW OVERALL IN THE LOWER LEVELS, WITH COOL TEMPERATURES CONTINUING ALTHOUGH SOME MODERATION SHOULD OCCUR SUNDAY AWAY FROM THE COAST. LOW PRESSURE MIGRATING FROM THE CENTRAL PLAINS TO THE UPPER OHIO VALLEY SUNDAY INTO MONDAY WILL PUSH A WARM FRONT TOWARD OUR AREA LATER SUNDAY. SOME WAA AND ISENTROPIC LIFT MAY BE ENOUGH TO PRODUCE SOME SHOWERS ESPECIALLY LATE SUNDAY. FOR MONDAY AND TUESDAY...THE EVOLUTION OF AN INITIAL CLOSED LOW WELL TO OUR WEST, AS IT MAY OPEN UP INTO THE EAST, DURING EARLY NEXT WEEK WILL DETERMINE OUR SENSIBLE WEATHER. SOME GUIDANCE INDICATES A FASTER EVOLUTION TO THIS FEATURE WHICH WOULD END ANY PRECIPITATION CHCS SOONER. THE FLOW OVERALL LOOKS LIKE IT COULD BE BLOCKY ENOUGH TO RESULT IN A SLOWER EASTWARD SHIFT OF THE SURFACE LOW, THEREFORE WE FAVORED WPC GUIDANCE THAT SHOWS THE LOW ARRIVING DURING TUESDAY. AS A RESULT, A POTENTIALLY UNSETTLED REGIME DURING THIS TIME FRAME. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TONIGHT...WIND SHIFT N-NE AND IFR OR MVFR CIGS DEVELOP SOUTHWESTWARD EVEN AS THE SHOWERS QUIT IN A LINGERING MOIST N-NE FLOW. CURRENT WLY GUSTY 25 KT WIND WILL SHIFT NE SOON AT KILG/KMIV. MAX NE GUSTS AROUND 25 KT INITIALLY WILL DIMINISH DURING THE NIGHT. WEDNESDAY...IFR AND MVFR CIGS TO START IMPROVE FROM N TO S TO CIGS BETWEEN 3000-4000 FT DURING MIDDAY WITH A N-NE WIND GUSTS UNDER 15 KT BECOMING LIGHT AND VARIABLE DURING THE AFTERNOON. OUTLOOK... WEDNESDAY NIGHT AND THURSDAY...POTENTIALLY LOWERING TO MVFR/IFR CONDITIONS ALONG WITH SHOWERS. FRIDAY...MVFR CEILINGS POSSIBLE TO START, OTHERWISE VFR. SATURDAY AND SUNDAY...VFR OVERALL, HOWEVER LOWER CEILINGS MAY DEVELOP LATER SUNDAY WITH SOME SHOWERS. && .MARINE...
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SCA ATLC WATERS. WAS TOO BUSY TO CANCEL THE MWW SCA AT 6P FOR DE BAY. SEAS INCREASED A BIT THIS EVENING SO THAT 4 TO 7 FT LOOKS GOOD OVERNIGHT. SEAS AND WINDS SLOWLY SUBSIDE WEDNESDAY. OUTLOOK... WEDNESDAY NIGHT THROUGH SUNDAY...THE WINDS OVERALL ARE ANTICIPATED TO BE BELOW 25 KNOTS, HOWEVER THE SEAS SHOULD BUILD TO ABOUT 5 FEET ON THE ATLANTIC COASTAL WATERS THURSDAY INTO THE WEEKEND WITH AN ONSHORE FLOW.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ450>455. && $$ SYNOPSIS...GORSE NEAR TERM...DRAG/KLEIN 804 SHORT TERM...KLEIN LONG TERM...GORSE AVIATION...DRAG/GORSE/KLEIN 804 MARINE...DRAG/GORSE/KLEIN 804

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