Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 300706 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 306 AM EDT TUE SEP 30 2014 .SYNOPSIS... A LOW PRESSURE SYSTEM AND WEAK FRONT WILL AFFECT THE WEATHER TODAY AND TONIGHT. HIGH PRESSURE WILL BUILD IN WEDNESDAY AND REMAIN THROUGH FRIDAY. A STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT INTO EARLY SATURDAY. HIGH PRESSURE WILL BUILD ACROSS THE AREA SATURDAY NIGHT INTO EARLY MONDAY. LOW PRESSURE WILL APPROACH FOR LATER MONDAY AND INTO NEXT TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THROUGH 7 AM...LIGHT SHOWERS SHOULD DIMINISH AND END OVER THE DELMARVA AND COASTAL NJ BY 7 AM. FOG WILL THICKEN OVER PORTIONS E PA WITH FOG POSSIBLE ALSO IN AREAS WHERE IT RAINED LATE YESTERDAY AND OVERNIGHT BUT APPARENTLY THE THICKEST FOG WILL BE FROM NW NJ THROUGH E PA SOUTHWESTWARD. TODAY...BETWEEN SHORT WAVES IT SHOULD BE QUIET THROUGH EARLY AFTERNOON WITH SOME SUNSHINE VSBY AT TIMES THROUGH THE CLOUDS. AFTERNOON HEATING DEVELOPS SMALL SHOWERS NW OF I95 WHICH PROBABLY HAVE A TENDENCY TO DRIFT WEST. IF THERE IS TO BE ANY THUNDER THIS FAR EAST...IT SHOULD BE CONFINED TO THE FAR WESTERN EDGE OF OUR FCST AREA. THE ECMWF SUGGESTS TEMPS MAY RUN 1-2 F WARMER THAN OUR FCST...ESP E MD. TEMPS ABOUT 7F WARMER THAN NORMAL. FCST WAS BASED ON A 50 50 BLEND OF THE 00Z/30 GFS/NAM MOS GUIDANCE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... TONIGHT...COOL POOL ALOFT SLIDES EASTWARD ACROSS THE REGION WITH 500MB TEMPS NEAR -15-16C. BANDS OF SHOWERS MAY BE OCCURRING WITH SUBTLE LIFT FROM BOTH WEAK BUT DEEP ELY MOIST WINDS NORTH OF I78 AND THE BACKDOOR COOL FRONT CONVERGENCE ZONE DRIVEN BY THE STRENGTHENING NE FLOW NE OF THE BACKDOOR CF. ADDITIONALLY FOG IS LIKELY TO DEVELOP IN THE COOLER BL AIR NE OF THE FRONTAL BOUNDARY. TEMPS ABOUT 10F WARMER THAN NORMAL. FCST WAS BASED ON A 50 50 BLEND OF THE 00Z/30 GFS/NAM MOS GUIDANCE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... VERY FEW CHANGES IN THE EXTENDED PERIOD FORECAST FROM 12 HOURS AGO. SEVERAL CHANCES FOR RAIN THROUGH THIS TIME PERIOD BUT AMOUNTS LOOK LIKE THEY WILL BE ON THE RELATIVELY LIGHT SIDE. TEMPERATURES FOR THE TIME PERIOD WILL BE SLIGHTLY ABOVE NORMAL EARLY IN THE PERIOD, THEN TRENDING TO NEAR NORMAL LATE IN THE PERIOD. HIGH PRESSURE BUILDS INTO THE REGION FOR LATE WEDNESDAY INTO FRIDAY. COLD FRONTAL BOUNDARY APPROACHING WITH NEXT UPPER LEVEL SYSTEM MOVES THROUGH LATE FRIDAY/EARLY SATURDAY BRINGING ANOTHER CHANCE OF RAIN. HIGHEST POPS THROUGH THE LONG TERM PERIOD ARE ASSOCIATED WITH THIS SYSTEM. HIGH PRESSURE BUILDS IN ONCE AGAIN FOR THE REMAINDER OF THE WEEKEND BEFORE A WARM FRONTAL BOUNDARY APPROACHES FROM THE SOUTHWEST LATE ON MONDAY, ONCE AGAIN BRINGING A CHANCE OF PRECIPITATION. USE WPC GUIDANCE PREDOMINATELY FOR DAYS 4 THOUGH 7. FOR TUE NIGHT INTO THU, USED A 50/50 BLEND OF PREVIOUS FORECAST AND ADJUSTED GFS MAV MOS && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THROUGH 12Z...AREAS OF LIGHT RAIN SHOWERS FROM MID LEVEL DECK OF CIGS AOA 6000 FT WITH A CLEARING TREND EXPECTED E PA OVERNIGHT. LIGHT SOUTH WIND WITH HIGHER THAN MODELED DEWPOINTS SHOULD FACILITATE THE DEVELOPMENT OF 1-3 MI FOG PATCHES AND POTENTIAL BRIEF LIFR CONDITIONS IN ST/FOG BOTH VCNTY KRDG/KABE BUT ALSO ELSEWHERE WHERE IT RAINED THIS PAST MONDAY AFTERNOON/EVENING. AFTER 12Z...AFTER ANY LEFTOVER IFR ST/FOG BURNS OFF BY 14Z...OTHERWISE SCT-BKN CLOUDS AOA 5000 FT WITH A POSSIBLE SHOWER VCNTY KRDG/KABE. LIGHT SOUTH WIND TURNING E. TONIGHT...WIND BECOMING NE AT 5-15 KT AND A DECK OF IFR ST/FOG SHOULD DEVELOP SOUTHWESTWARD FROM LONG ISLAND BEHIND THE BACKDOOR COLD FRONT CURRENTLY MOVING SW FROM SOUTHERN NEW ENGLAND. CHANCE OF SHOWERS...MAINLY N OF KPHL. OUTLOOK... WEDNESDAY...MAINLY VFR CIGS WITH POSSIBLE MVFR CONDITIONS IN SHOWERS KABE/KRDG/KTTN DURING THE MORNING. E/NE WINDS GUST 15 KNOTS. THURSDAY...POSSIBLE MVFR FOG EARLY OTHERWISE VFR SCT-BKN CLOUDS AOA 4000 FT. N-NW WIND GUST 15 KT. FRIDAY...VFR CIGS EXCEPT POSSIBLE MVFR CONDITIONS IN ST/FOG EARLY FRIDAY MORNING AND THEN AGAIN FRIDAY NIGHT IN SHOWERS NEAR A COLD FRONT. E-SE WIND BECOMING S OR SW LATE AT NIGHT. SATURDAY...VFR CONDITIONS EXPECTED. && .MARINE... NO HEADLINES ATTM. TODAY...LIGHT WINDS AND SEAS AOB 3 FT TODAY WITH THE S-SW WIND TURNING TO THE EAST OR NORTHEAST. TONIGHT...NE WINDS INCREASING WITH GUSTS TO 22 KT LATE AND SEAS BUILDING TO NEAR 4 FT BY SUNRISE WEDNESDAY. CAPPED SEAS AT 4 FT THROUGH 8AM WEDNESDAY AS I BELIEVE THE GFS WW3 GUIDANCE IS TOO SOON TOO HIGH. OUTLOOK... WEDNESDAY THROUGH WEDNESDAY NIGHT: NE FLOW WEDNESDAY AND WEDNESDAY NIGHT SHOULD INCREASE TO SCA CRITERIA ALONG THE NNJ COAST AND THEN POSSIBLY SOUTHWARD TO THE ENTIRE ATLANTIC COAST LATER WEDNESDAY OR WEDNESDAY NIGHT. DELAWARE BAY MAY NOT SEE WIND GUSTS ABOVE 22 KT WITH ANY SCA HEADLINE THERE NOT LIKELY. HAVE HELD OFF ON ISSUING ANY FORMAL HEADLINES ON THIS FORECAST UPDATE AS CONDITIONS WILL JUST MEET LOWER END SCA CRITERIA AND CONFIDENCE IS NOT YET HIGH. THURSDAY...SMALL CHANCE OF SCA SEAS ON THE ATLANTIC WATERS FROM NE SWELLS GENERATED BY AN OFFSHORE LOW. FRIDAY...WIND BECOMING SOUTH BY NIGHT. SMALL CHANCE OF AN SCA AT NIGHT. SATURDAY...SCA CONDITIONS POSSIBLE EARLY WITH COLD FRONT PASSAGE, THEN IMPROVING CONDITIONS EXPECTED. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...DRAG/SZATKOWSKI 305 NEAR TERM...DRAG 305 SHORT TERM...DRAG 305 LONG TERM...SZATKOWSKI AVIATION...DRAG/SZATKOWSKI 305 MARINE...DRAG/GAINES/SZATKOWSKI/HEAVENER 305

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