Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 010933 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 533 AM EDT WED JUL 1 2015 .SYNOPSIS... A WARM FRONT WILL LIFT NORTHEAST OF THE AREA THIS MORNING. A COLD FRONT FROM THE EASTERN GREAT LAKES SHOULD THEN MOVE THROUGH LATE TONIGHT. THE COLD FRONT IS EXPECTED TO STALL JUST SOUTH OF OUR REGION FOR THE REMAINDER OF THE WEEK AS WAVES OF LOW PRESSURE MOVE ALONG IT. A SECOND COLD FRONT SHOULD ARRIVE SATURDAY NIGHT FOLLOWED BY WEAK HIGH PRESSURE FOR SUNDAY. A WARM FRONT SHOULD THEN MOVE THROUGH THE REGION ON MONDAY WITH A COLD FRONT REACHING THE GREAT LAKES ON TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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THE HEAVY SHOWERS/THUNDERSTORMS ASSOCIATED WITH A STRONG SHORT WAVE/VORTICITY IMPULSE MOVING ACROSS THE AREA HAS LIFTED TO OUR NORTHEAST. THERE WILL REMAIN SOME LIGHT RAIN ACROSS THE AREA THIS MORNING, BUT THE HEAVY RAIN HAS ENDED, SO WE HAVE CANCELLED THE FLASH FLOOD WATCH. AFTER THE MORNING SHOWERS/THUNDERSTORMS MOVE OUT AND END, THE REST OF THE MORNING INTO THE EARLY AFTERNOON MAY SEE A BREAK IN PRECIPITATION. HOWEVER, AS THE COLD FRONT APPROACHES LATER IN THE DAY AND ANOTHER SHORT WAVE/VORTICITY IMPULSE MOVES ACROSS THE AREA, SCATTERED SHOWERS/THUNDERSTORMS MAY ONCE AGAIN DEVELOP ACROSS THE AREA, ESPECIALLY THE WESTERN HALF. HIGHS TODAY ARE A BLEND OF MAV/MET MOS AND MOSGUIDE AND MIXED 925 MB ECMWF TEMPERATURES. WINDS DURING THE DAY WILL ALSO GUST AROUND 20-25 MPH. WE ARE EXPECTED TO PERFORM STORM SURVEYS TODAY AFTER 9 AM IN CHESTER COUNTY AND THE LEHIGH VALLEY TO INVESTIGATE THE POSSIBILITY OF TORNADO OCCURRENCES ON TUESDAY.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... THE COLD FRONT WILL MOVE ACROSS THE AREA THIS EVENING, WHILE THE SHORT WAVE/VORTICITY ALOFT FOLLOWS ALONG. THERE WILL CONTINUE TO BE THE CHANCE FOR ISOLATED SHOWERS/THUNDERSTORMS THIS EVENING, BEFORE THEY DIMINISH AND MOVE OUT OF THE AREA AS THE FRONT MOVES EASTWARD. THE ENTIRE AREA SHOULD BE RAIN FREE BY MIDNIGHT. LOWS TONIGHT ARE A BLEND OF MAV/MET MOS AND MOSGUIDE. THE COLD FRONT PUSHES SOUTH OF THE AREA AND STALLS OUT THURSDAY INTO THURSDAY NIGHT. WHILE THE FRONT WILL BE WELL SOUTH OF THE AREA, THERE WILL REMAIN SEVERAL SHORT WAVE/VORTICITY IMPULSES SLIDING ACROSS OUR SOUTHERN AREAS. THE MAJORITY OF THE PRECIPITATION SHOULD REMAIN TO OUR SOUTH, BUT THERE WILL REMAIN THE POSSIBILITY FOR SHOWERS/THUNDERSTORMS TO AFFECT SOUTHERN NEW JERSEY AND THE DELMARVA. HIGHS THURSDAY ARE A BLEND OF MAV/MET MOS AND MOSGUIDE AND MIXED 925 MB ECMWF TEMPERATURES. LOWS THURSDAY NIGHT ARE A BLEND OF MAV/MET MOS AND MOSGUIDE. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE WRF-NMMB LOOKED BETTER AT 500MB AND 850MB WITH AN EQUAL SPLIT AT 925MB. THIS CASTS SOME DOUBT ON THE GFS SOLUTION FOR THE LONG TERM. THERE REMAINS BOTH A TIMING AND LATITUDINAL SPLIT WITH THE MEDIUM RANGE MODELS WITH THE GFS SLOWEST AND FARTHEST NORTH. THERE APPEARS TO BE SOME FEEDBACK VORTS WITH THE GFS AND THE GEFS PCPN MEAN IS LOWER THAN THE OP. REGARDLESS ONGOING SVR AND FLOODING HAS MADE US LEAN HEAVILY ON PMDHMD (ECMWF PREFERENCE) AND WPC FOR THE LONG TERM. FRIDAY, WE ARE KEEPING A CHANCE FOR SHOWERS IN THE SOUTHERN HALF OF OUR CWA. MAX TEMPS HIGHER THAN MEX GUIDANCE, BUT LOWER THAN PREVIOUS FORECAST. PRESERVATION OF CONTINUITY WE KEPT A CHANCE OF THUNDERSTORMS IN FOR INDEPENDENCE DAY. HERE THE ECMWF IS MORE PESSIMISTIC. SUNDAY CONTINUES TO BE THE CONSENSUS BETTER WEEKEND DAY WITH THE FRONTAL BOUNDARY PUSHED FARTHER TO THE SOUTH. THE RETURNING WARM FRONT SHOULD THEN BRING PCPN CHANCES BACK ON MONDAY AND THE APPROACHING COLD FRONT PROVIDING AN ADDITIONAL CHANCE COME TUESDAY. UNCERTAINTY REMAINS HIGHER THAN AVERAGE, BUT TEMPERATURES FAVOR AT OR COOLER THAN NORMAL THROUGH INDEPENDENCE DAY WITH A RETURN OF MORE WARMER AND HUMID WEATHER FOR THE BACK END OF THE LONG TERM. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THE HEAVY SHOWERS/THUNDERSTORMS HAVE LIFTED TO OUR NORTHEAST AND CONDITIONS HAVE MOSTLY IMPROVED TO VFR. A BRIEF PERIOD OF MVFR FOG IS POSSIBLE THIS MORNING AROUND AND SHORTLY AFTER SUNRISE. HOWEVER, AS THE MORNING PROGRESSES, ANY FOG THAT DEVELOPS WILL BURN OFF AND A RETURN TO VFR IS EXPECTED FOR THE REMAINDER OF THE DAY. SOUTH-SOUTHWEST WINDS EARLY THIS MORNING WILL BECOME MORE SOUTHWESTERLY LATER THIS MORNING INTO THIS AFTERNOON. WINDS WILL ALSO GUST 15-20 KNOTS THIS AFTERNOON, BEFORE THE GUSTS DROP OFF AROUND SUNSET AND BECOME MORE WEST-NORTHWEST OVERNIGHT. WINDS MAY ACTUALLY BECOME LIGHT AND VARIABLE FOR MANY AREAS OVERNIGHT. VFR CONDITIONS WILL REMAIN FOR THE FIRST PART OF TONIGHT, BUT THERE IS THE POSSIBILITY THAT SOME LIGHT FOG MAY DEVELOP OVERNIGHT THROUGH DAYBREAK THURSDAY. OUTLOOK... THURSDAY THROUGH SATURDAY...PREDOMINATELY VFR, BUT SOME MVFR OR IFR CONDITIONS DURING SCATTERED SHOWERS AND THUNDERSTORMS. IMPACT OUTLOOKED TO BE GREATER FOR SOUTHERN AIRPORTS AND TERMINALS. SATURDAY NIGHT AND SUNDAY...VFR CONDITIONS EXPECTED.
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&& .MARINE... A SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS HAS BEEN ISSUED FOR THE ATLANTIC COASTAL WATERS FOR TODAY INTO TONIGHT. SEAS ARE AROUND 4 FEET EARLY THIS MORNING AND ARE EXPECTED TO INCREASE TO 5 FEET THROUGH THE DAY. A SMALL CRAFT ADVISORY HAS ALSO BEEN ISSUED FOR DELAWARE BAY AS WINDS ARE GUSTING AROUND 25 KNOTS THIS MORNING. WINDS SHOULD DIMINISH LATER THIS MORNING, SO WE WILL RUN THIS ONE THROUGH 11 AM. OUTLOOK... THURSDAY AND THURSDAY NIGHT...WINDS AND SEAS SHOULD REMAIN BELOW SCA CRITERIA. FRIDAY THROUGH SATURDAY...SEAS ON THE SOUTHERN OCEAN WATERS MIGHT REACH SMALL CRAFT ADVISORY LEVELS PENDING THE STRENGTH OF THE LOW PRESSURE SYSTEM ON THE FRONTAL BOUNDARY. CONFIDENCE IS LESS THAN AVERAGE. SUNDAY...SUB SMALL CRAFT ADVISORY CONDITIONS EXPECTED. && .RIP CURRENTS... BASED ON OUR LOCAL FORECAST APPLICATION USING A 5 FOOT WAVES/7 SECOND PERIOD AND SOUTHWEST WIND AROUND 12 KNOTS, WE WILL CONTINUE WITH A MODERATE RISK OF RIP CURRENTS FOR NEW JERSEY AND LOW FOR DELAWARE. && .EQUIPMENT... PCPN MEASURER ERROR AT KPHL, ESTIMATED AMOUNT OF 1.5" ON 6/30 MAY BE ADJUSTED LATER TODAY. && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EDT THURSDAY FOR ANZ450>455. SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR ANZ430- 431.
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&& $$ SYNOPSIS...GIGI NEAR TERM...ROBERTSON SHORT TERM...ROBERTSON LONG TERM...GIGI AVIATION...GIGI/ROBERTSON MARINE...GIGI/ROBERTSON RIP CURRENTS... EQUIPMENT...

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