Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 230417 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1217 AM EDT WED JUL 23 2014 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO MOVE EASTWARD TONIGHT ALLOWING FOR A BETTER RETURN FLOW TOMORROW AHEAD OF A POTENT COLD FRONT. THE FRONT SHOULD MOVE THROUGH LATER ON WEDNESDAY INTO THURSDAY MORNING. HIGH PRESSURE WILL FILL IN BEHIND THE DEPARTING FRONT THROUGH THE FIRST HALF OF THE WEEKEND BEFORE A COMPLEX SYSTEM APPROACHES SUNDAY SPILLING INTO THE NEW WORK WEEK. && .NEAR TERM /THROUGH WEDNESDAY/... THE 1130 PM UPDATE DELAYED THE ONSET OF FOG SLIGHTLY...AND ADJUSTED THE TEMPS SLIGHTLY BASED ON LATE EVENING TRENDS. FAIR OVERNIGHT...PATCHY FOG LATE. MOST OF IT SHOULD BE CONFINED THE I78 REGION NWWD. WEDNESDAY...LITTLE CHANGE IN PREVIOUS MODEL GUIDANCE WHICH STATES WIDESPREAD LOWER 90S (NEAR 18C 850 MB AND 925MB HOTTEST TEMPS ARE JUST WEST AND NORTHWEST OF OUR FCST AREA). POCONOS AND IMMEDIATE ATLC SHORE A BIT COOLER. HEAT INDEX UPPER 90S. NO HEAT ADVY IN THIS CONTINUING SUMMER BEREFT OF HEAT. TSTMS PROBABLY RESTRICTED TO NW NJ AND NE PA AFTER 21Z...POSSIBLY A SECOND CLUSTER CROSSING CHES BAY? TT 48+ SWI -2 KI INCREASING TO 38C VCNTY POCS AND E VA. APPEARS TO BE A SEE TEXT CASE...UNLIKELY SVR THROUGH 00Z DUE TO LACK OF BULK SHEAR...500MB WINDS UNDER 30 KT AND MLCAPE CLOSER TO 1600J. NOTE THAT THERE SHOULD BE CU FIELDS FORMING THIS MORNING OVER NNJ IN A LEADING EDGE AREA OF KI 33C BUT WITH LITTLE OR NO PRIMARY FORCING AM NOT EXPECTING TO YIELD ANY LATE MORNING TSTMS IN NNJ AS THIS LEAD AREA OF INSTABILITY SHOVES ENE TO LI BY 18Z. PROBABLY A 50 50 BLEND OF THE 00Z/23 NAM/GFS GUIDANCE IN THE 330 AM ISSUANCE. && .SHORT TERM /WEDNESDAY NIGHT/... SLOW SEWD PROGRESS OF THE COLD FRONT INTO THE UNSTABLE AIRMASS SHOULD YIELD BANDS OF TSTMS INTO THE EARLY NIGHT BUT NOT NECESSARILY WIDESPREAD. ONE OR 2 TSTMS COULD BE SVR BUT BULK SHEAR IS MARGINAL AT WORST FOR SVR AND ONLY THE TT AND SOME CAPE ALLOW FOR MODEST ISOLATED SVR POTENTIAL. PWAT 1.8 INCHES OFFERS A CHANCE OF NARROW PATHS OF 2 INCH RAINS BENEATH THE BIGGEST STORMS. 50 50 BLEND OF THE 00Z/23 GFS/NAM GUIDANCE IN THE 330 AM ISSUANCE. && .LONG TERM /THURSDAY THROUGH TUESDAY/... THE BASE OF THE TROUGH BEGINS TO FLATTEN OUT BY FRIDAY, THOUGH NOT ENTIRELY BECOMING ZONAL. THIS YIELDS SLIGHTLY BELOW NORMAL TEMPERATURES AND DECREASED CHANCES FOR CONVECTION GIVEN A DRIER AIRMASS IN PLACE. STILL A BIT UNCERTAIN ABOUT THE SATURDAY EVENING TIMEFRAME AS SOME OF THE OPERATIONAL GUIDANCE SWINGS A PIECE ENERGY THROUGH THE BASE OF THE TROUGH WHICH COULD TOUCH OFF A COUPLE STRAY/ISOLATED SHOWERS...BETTER EAST THAN WEST WITH BETTER MOISTURE POOLING AND SEABREEZE INTERACTION. RIDGING BUILDS INTO THE WEST SENDING STRONGER SHORTWAVES OF ENERGY INTO THE TROUGH OVERHEAD ALLOWING FOR ANOTHER BOUT OF DEEPER TROUGHING. EXPECT UNSETTLED WEATHER THROUGH THE REMAINDER OF THE LONGTERM AS A SERIES OF EMBEDDED WAVES PUSHES THROUGH ALOFT TOUCHING OFF SHOWERS AND THUNDERSTORMS. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. EARLY THIS MORNING BEFORE 12Z...PRIMARILY VFR WITH SCT CLOUDS AOA 4000 FT. PATCHY 2 TO 5 MI FOG IN THE COUNTRYSIDE TAF LOCATIONS BUT CONFIDENCE IS LESS THAN IT WAS AT THIS TIME YDY. TEMP-DEWPOINT SPREADS AT MIDNIGHT ARE JUST TOO LARGE. LIGHT S-SW WIND. TODAY AFTER 12Z...VFR SCT AOA 5000 FT. BRIEFLY BKN CIGS NEAR 5000 FT VCNTY KABE AND KRDG THIS AFTN AND SLIGHT CHC OF A TSTM THERE AFTER 22Z. SW WIND G 17 KT THIS AFTN MOST TAF LOCATIONS. TONIGHT...VFR CIGS WITH A BETTER CHC OF BRIEF IFR CONDS IN TSTMS. LIGHT SW WIND SHIFT N TOWARD MORNING WHEN PATCHY IFR ST/FOG MIGHT FORM IN THE FRONTAL ZONE OR WHERE IT RAINS THIS EVENING. OUTLOOK... THURSDAY...MVFR AND IFR CONDITIONS AT TIMES IN SHOWERS AND THUNDERSTORMS. PATCHY FOG THU MORNING. THURSDAY NIGHT THROUGH SATURDAY...MAINLY VFR. SUNDAY...SUB-VFR POSSIBLE IN SCATTERED SHOWERS AND THUNDERSTORMS. && .MARINE... NO HEADLINES THROUGH WEDNESDAY NIGHT. MAINLY S-SW WIND G UNDER 20 KT SHIFT TO NORTH TOWARD DAWN THURSDAY. WAVE HEIGHTS ON OUR OCEAN WATERS SHOULD BE 2 TO 4 FEET. WAVES ON DELAWARE BAY ARE EXPECTED TO BE 2 FEET OR LESS. SCATTERED THUNDERSTORMS TONIGHT. OUTLOOK... THURSDAY THROUGH SUNDAY...HIGH PRESSURE OVERHEAD WILL KEEP SEAS AND WINDS BELOW SCA CRITERIA. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...HEAVENER NEAR TERM...DRAG 1218A SHORT TERM...DRAG/IOVINO 1218A LONG TERM...HEAVENER AVIATION...DRAG/HEAVENER 1218A MARINE...DRAG/HEAVENER 1218A

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