Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 310752 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 352 AM EDT FRI JUL 31 2015 .SYNOPSIS...
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A WEAK FRONT WILL STALL TO OUR SOUTH AND EAST TODAY WHILE WEAK HIGH PRESSURE IS CENTERED TO OUR WEST. THE NEXT WEAK COLD FRONT IS FORECAST TO CROSS OUR AREA LATE SATURDAY INTO SUNDAY, THEN STALL OFFSHORE DURING SUNDAY INTO MONDAY. A STRONGER COLD FRONT IS EXPECTED TO ARRIVE LATER TUESDAY, THEN STALL NEARBY WEDNESDAY INTO THURSDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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WHAT A DIFFERENCE A DAY CAN MAKE! DRIER AIR HAS BEEN FILTERING INTO THE REGION THROUGH THIS MORNING AND IT CERTAINLY FEELS GORGEOUS OUT THERE. TEMPERATURES TODAY WILL STILL RISE INTO THE UPPER 80S TO LOWER 90S. HOWEVER, WITH THOSE LOWER DEWPOINTS IN PLACE, IT WILL NOT FEEL QUITE THAT HOT OUTSIDE. PLENTY OF SUNSHINE AS THE CLOUDS LEAVE US FOR THE DAY. OVERALL, A BEAUTIFUL SUMMER FRIDAY FOR OUR REGION.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
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THE BEAUTIFUL DAY TURNS INTO A BEAUTIFUL NIGHT. DRY AIR REMAINS ACROSS THE REGION AND SOME SLIGHTLY COOLER TEMPERATURES WILL WORK THEIR WAY IN AS WE RETAIN THAT NORTHWEST FLOW INTO THE EVENING BEFORE IT BECOMES SOUTHWESTERLY OVERNIGHT. LOWS WILL DROP INTO THE 60S TO AROUND 70 THROUGH MUCH OF THE AREA.
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&& .LONG TERM /SATURDAY THROUGH THURSDAY/...
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THE SYNOPTIC SETUP IS COMPRISED OF AN UPPER-LEVEL TROUGH FROM THE GREAT LAKES TO THE NORTHEAST THAT AMPLIFIES SOME SATURDAY INTO SUNDAY. A WEAK FRONT MOVES THROUGH LATE SATURDAY INTO SUNDAY, THEN THE NEXT ONE WHICH COULD BE STRONGER ARRIVES DURING TUESDAY BEFORE STALLING NEARBY WEDNESDAY INTO THURSDAY. THE CONVECTIVE CHCS WILL BE DETERMINED BY HOW MUCH MOISTURE RETURN CAN OCCUR AHEAD OF EACH SURFACE FRONT, AND THE ACTUAL AMPLITUDE OF THE TROUGH AND ITS ASSOCIATED LARGE SCALE ASCENT. WE USED A MODEL BLEND SATURDAY THROUGH MONDAY, THEN WENT WITH A WPC/CONTINUITY BLEND THEREAFTER. FOR SATURDAY AND SUNDAY...AN UPPER-LEVEL TROUGH REMAINS ACROSS THE NORTHEAST ALTHOUGH IT SHOULD WEAKEN SOME SUNDAY AS IT RELOADS ACROSS THE MIDWEST. A FRONTAL ZONE IS FORECAST TO MOVE THROUGH LATE SATURDAY INTO SUNDAY, AND THE GREATEST LIFT AND SHEAR IS MOSTLY FROM NEAR OUR NORTHERN ZONES ON NORTHWARD INTO NEW ENGLAND. THE DEW POINTS SHOULD START TO INCH BACK UPWARD AGAIN LATER SATURDAY, HOWEVER LOW ENOUGH MOISTURE LEVELS MAY LIMIT CONVECTIVE DEVELOPMENT. SOME GUIDANCE DOES INITIATE MORE CONVECTION BY LATE SATURDAY FROM NORTHEASTERN PENNSYLVANIA TO NORTHERN NEW JERSEY THEN SLIDES IT SOUTHEASTWARD. THERE MAY BE ENOUGH SHEAR WITH INCREASING INSTABILITY TO ALLOW FOR A GUSTY THUNDERSTORM, HOWEVER THIS IS DEPENDENT ON THE AIR MASS MOISTENING UP SUFFICIENTLY AS THE UPPER-LEVEL TROUGH REMAINS IN PLACE. FOR NOW, WE CONTINUED SOME SLIGHT CHC POPS ACROSS THE NORTHERN AREAS SATURDAY AFTERNOON FOR THE POTENTIAL FOR AT LEAST SOME ISOLATED THUNDERSTORMS. THE FRONT LOOKS TO STALL OFFSHORE GIVEN WEAKER FLOW WITH A SOUTHEASTERN EXTENT, HOWEVER SOME WEAK IMPULSES MAY TRACK ALONG IT. IT APPEARS THAT ANY CONVECTION LEFTOVER WITH THE FRONT IS OFFSHORE, THEREFORE WE MAINTAINED A DRY SUNDAY. IT WILL CONTINUE TO BE WARM TO EVEN HOT HOWEVER THE DEW POINTS ARE EXPECTED TO REMAIN LOW TO NOT REALLY HAVE AN IMPACT /ALTHOUGH SOME INCREASE SHOULD BEGIN SUNDAY NIGHT ESPECIALLY ACROSS THE SOUTHERN AND EASTERN AREAS/. FOR MONDAY AND TUESDAY...AS THE UPPER-LEVEL TROUGH RELOADS FROM THE WEST, IT MAY SUPPORT WEAK IMPULSES TRAVERSING THE OFFSHORE FRONT HOWEVER THESE LOOK TO REMAIN SEPARATED FROM THE INCOMING AMPLIFYING TROUGH. THE UPPER-LEVEL FLOW TURNING MORE SOUTHWESTERLY FOR A TIME WILL HELP PULL SOME LOW-LEVEL MOISTURE NORTHWARD, RESULTING IN AT LEAST SOME MUGGINESS RETURNING. SOME LARGE SCALE ASCENT WITH THE TROUGH ALONG WITH A COLD FRONT ARRIVING DURING TUESDAY SHOULD RESULT IN SOME SHOWERS AND THUNDERSTORMS. THE STRONGER SHEAR AND LIFT HOWEVER MAY GLANCE OUR AREA, AND AS A RESULT THE MODEL GUIDANCE SHOWS VARIATION IN THE CONVECTIVE CHCS AND COVERAGE. WE CARRIED SOME SLIGHT CHC POPS MOSTLY MONDAY AFTERNOON, THEN LOW CHC FOR TUESDAY. FOR WEDNESDAY AND THURSDAY...AS THE UPPER-LEVEL TROUGH STARTS TO WEAKEN IN THE NORTHEAST, THE FRONTAL BOUNDARY FROM TUESDAY SHOULD SLOW OR EVEN STALL IN OUR VICINITY. THIS COULD HELP FOCUS SOME CONVECTIVE DEVELOPMENT ESPECIALLY DURING PEAK HEATING, ALTHOUGH AS OF NOW THE OVERALL FORCING LOOKS WEAK AND MORE CONCENTRATED BACK INTO THE OHIO VALLEY ASSOCIATED WITH AN IMPULSE /POSSIBLY CONVECTIVELY INDUCED/. THERE IS INCREASED UNCERTAINTY AS THE CHC FOR SHOWERS AND STORMS WILL DEPEND ON THE POSITIONING OF THE UPPER-LEVEL TROUGH, THE FRONTAL ZONE PLACEMENT AND POSSIBLE SURFACE WAVE DEVELOPMENT. THE AIR MASS LOOKS TO BE COOLING THOUGH DURING THIS TIME FRAME AND THIS IS REFLECTED IN THE HIGH/LOW TEMPERATURE FORECASTS.
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&& .AVIATION /08Z FRIDAY THROUGH TUESDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...MVFR/IFR EARLY AT KMIV AND KACY, WHERE MORE LOW LEVEL MOISTURE REMAINS IN PLACE. EXPECT IMPROVING CONDITIONS WITH VFR RETURNING TO THOSE SITES AROUND 12-14Z. ELSEWHERE, DRIER AIR HAS STARTED TO FILTER IN AND VFR CONDITIONS PREVAIL. SKIES WILL REMAIN CLEAR THROUGH MUCH OF THE DAY WITH FEW CLOUDS AROUND. LIGHT WINDS THIS MORNING WILL BECOME WEST TO NORTHWEST AROUND 8 TO 12 KNOTS FOR THIS AFTERNOON. TONIGHT...VFR CONDITIONS EXPECTED. FEW TO NO CLOUDS AROUND. WINDS WILL SUBSIDE DURING THE EVENING AND OVERNIGHT, GRADUALLY TURNING MORE TO THE SOUTHWEST. OUTLOOK... SATURDAY...VFR OVERALL. A FEW POSSIBLE SHOWERS OR THUNDERSTORMS IN THE AFTERNOON AND EVENING MAINLY NORTH OF KPHL. SUNDAY...VFR. MONDAY AND TUESDAY...SOME SHOWERS AND THUNDERSTORMS POSSIBLE ESPECIALLY DURING TUESDAY AFTERNOON, OTHERWISE VFR.
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&& .MARINE...
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WEST TO NORTHWEST WINDS WILL BE AROUND 10 TO 15 KNOTS THIS MORNING AND THEN SUBSIDING A BIT TOWARD THIS AFTERNOON AND EVENING. WINDS WILL GRADUALLY TURN MORE TO THE SOUTHWEST TOWARD THIS EVENING AND OVERNIGHT. SEAS WILL GENERALLY REMAIN IN THE 2 TO 4 FOOT RANGE. OUTLOOK... SATURDAY THROUGH TUESDAY...THE CONDITIONS OVERALL ARE ANTICIPATED TO BE BELOW SMALL CRAFT ADVISORY CRITERIA. A SOUTHERLY FLOW SATURDAY SHOULD INCREASE AHEAD OF A WEAK COLD FRONT WITH GUSTS TO ABOUT 20 KNOTS FOR A TIME, AND THIS LOOKS TO OCCUR AGAIN LATER MONDAY AHEAD OF ANOTHER COLD FRONT. THIS WILL RESULT IN AN INCREASE IN THE SEAS AT TIMES, ALTHOUGH CURRENTLY EXPECTING THESE TO REMAIN UNDER 5 FEET.
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...GORSE NEAR TERM...MEOLA SHORT TERM...MEOLA LONG TERM...GORSE AVIATION...GORSE/MEOLA MARINE...GORSE/MEOLA

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