Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 060315 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1115 PM EDT SUN JUL 5 2015 .SYNOPSIS... WEAK HIGH PRESSURE WILL SHIFT OFF THE COAST TONIGHT AND MONDAY. A WARM FRONT IS FORECAST TO LIFT NORTHWARD AND THROUGH OUR REGION MONDAY NIGHT INTO TUESDAY MORNING. ANOTHER FRONTAL BOUNDARY IS EXPECTED TO ARRIVE ON WEDNESDAY, THEN THE FRONT IS ANTICIPATED TO MEANDER IN OR NEAR OUR REGION WEDNESDAY NIGHT INTO FRIDAY AS LOW PRESSURE MOVES ALONG IT. WEAK HIGH PRESSURE MAY TRY TO BUILD DOWN FROM THE NORTHWEST NEXT WEEKEND AS THE FRONT REMAINS NEARBY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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11 PM ESTF: UPDATED EARLY FOR SHOWERS PHL SOUTHWARD BY 11Z ESPECIALLY DELMARVA WHERE PWAT INCREASES TO 2 INCHES. NO THUNDER IN THE FCST BUT THE OVERALL NNEWD PROGRESS OF THE NC WARM FRONT AND DEEPER CYCLONIC CIRCULATION OVER WVA/OH/KY, THE 02Z COSPA AND 00Z/6 NAM PROMPTED THE MOVE TO INCREASE POPS CONSIDERABLY ALONG MD E SHORE AND DE. MODELED STABILIZING OF THE ATMOSPHERE BY MORNING IS THE ONLY REASON NO THUNDER IS IN THE FORECAST. SKYCOVER WAS INCREASED OVER OUR AREA AS WELL, ESPECIALLY PHL SOUTHWARD. NO CHANGES TO THE TEMPS ATTM.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... AN AREA OF SHOWERS WILL BRING THE BEST CHCS OF RAIN TO THE DELMARVA AND WRN SECTIONS OF THE AREA DURG THE DAY. IT IS PSBL THAT ERN AREAS REMAIN DRY, BUT WILL CARRY VERY LOW POPS IN THESE LOCATIONS LATER IN THE DAY. OVERALL THE AVERAGE QPF APPEARS TO BE ON THE LOWER SIDE, HOWEVER LOCAL DOWNPOURS /HIGHER QPF/ CAN OCCUR GIVEN PW VALUES FORECAST TO BE ABOUT 2.00 INCHES. HIGH TEMPS WILL BE IN THE MID TO UPPER 80S. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... THE MID LEVEL RIDGE THAT WAS OVER THE WESTERN STATES IS FORECAST TO DISAPPEAR FOR THE NEW WEEK AS LOW PRESSURE MEANDERS OFF THE CALIFORNIA COAST, MOVES INLAND AND FILLS. THE MID LEVEL FLOW EAST OF THE ROCKIES IS EXPECTED TO BECOME SOMEWHAT ZONAL, RESULTING IN ANOTHER POTENTIALLY ACTIVE WEEK FOR OUR REGION. THE WESTERN RIDGE IS ANTICIPATED TO RETURN NEXT WEEKEND. IT CONTINUES TO APPEAR AS THOUGH A WAVERING FRONTAL BOUNDARY TO OUR SOUTH WILL RETURN NORTHWARD AS A WARM FRONT ON MONDAY NIGHT. THE BOUNDARY IS EXPECTED TO PASS THROUGH OUR REGION FROM MONDAY NIGHT INTO TUESDAY MORNING. AS A RESULT, WE MAY SEE SOME LOW CLOUDS AND PATCHY FOG AND HAZE, ALONG WITH A CHANCE OF SHOWERS OR A THUNDERSTORM. A MID LEVEL SHORT WAVE TROUGH IS FORECAST TO BE LOCATED OVER THE UPPER OHIO RIVER VALLEY AND VICINITY ON MONDAY EVENING. THE FEATURE WILL DRIFT EASTWARD AND IT IS EXPECTED TO PASS OVER OUR REGION ON TUESDAY AFTERNOON. THE INCREASE IN MOISTURE AND THE DEVELOPMENT OF INSTABILITY DUE TO DAYTIME HEATING ALONG WITH THE MID LEVEL TROUGH PASSING OVERHEAD COULD RESULT IN THE DEVELOPMENT OF SCATTERED SHOWERS AND THUNDERSTORMS ON TUESDAY AFTERNOON. THE GREATEST POTENTIAL APPEARS TO BE IN EASTERN PENNSYLVANIA AND NORTHERN AND CENTRAL NEW JERSEY WHERE MIXED LAYER CAPE VALUES ARE FORECAST TO RISE AROUND OR JUST ABOVE 1000 J/KG. THE TIMING OF ADDITIONAL IMPULSES IN THE NEARLY ZONAL MID LEVEL FLOW DURING THE MID AND LATE WEEK PERIOD BECOMES A BIT OF A CHALLENGE AFTER THE INITIAL MID LEVEL TROUGH PASSES ON TUESDAY AFTERNOON. WHILE IT SEEMS THAT CONVECTION WILL OCCUR IN PARTS OF OUR AREA ON WEDNESDAY, AND PERHAPS ON THURSDAY AND FRIDAY, AS WELL, THE EXACT LOCATION OF THE GREATEST POTENTIAL REMAINS A LOW CONFIDENCE FORECAST. PRESENTLY, IT LOOKS AS THOUGH OUR HIGHEST CHANCE FOR SEVERE THUNDERSTORMS MAY BE ON WEDNESDAY AFTERNOON AND EVENING WITH THE ARRIVAL OF THE FRONT FROM THE NORTHWEST. THE FORECAST WIND PROFILES FOR THAT TIME PERIOD SUGGEST THAT IF CONVECTION DEVELOPS IT COULD BECOME ORGANIZED. CAPE VALUES IN EXCESS OF 1000 J/KG ARE ANTICIPATED. THE LATEST GENERAL TIMING OF THE MAIN SURFACE LOW RIDING ALONG THE FRONTAL BOUNDARY BRINGS IT ACROSS OUR REGION ON THURSDAY NIGHT. AS IS THE CASE WITH THE MID LEVEL FEATURES, THE TIMING OF THE SURFACE WAVE REMAINS IN QUESTION. WE WILL KEEP A CHANCE OF SHOWERS AND THUNDERSTORMS FOR THURSDAY INTO THURSDAY NIGHT, WITH MAINLY A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS FOR FRIDAY. PRECIPITABLE WATER VALUES ARE FORECAST TO RISE NEAR OR ABOVE 2 INCHES DURING THE MID AND LATE WEEK PERIOD. ANY THUNDERSTORMS COULD BRING HEAVY DOWNPOURS ALONG WITH LOCALIZED FLOODING OF ROADWAYS AND AREAS OF POOR DRAINAGE. ALSO, WE WILL KEEP AN EYE ON THE FLASH FLOODING POTENTIAL ESPECIALLY IF CERTAIN AREAS ARE AFFECTED BY HEAVY RAINFALL ON MORE THAN ONE DAY. THE GUIDANCE DIFFERS WITH THE FORECAST FOR NEXT WEEKEND. THE MAIN QUESTION CONCERNS WHETHER THE FRONTAL BOUNDARY WILL BE PUSHED FAR ENOUGH SOUTH TO ALLOW WEAK HIGH PRESSURE TO BUILD INTO OUR REGION FROM THE NORTHWEST AND NORTH. AS A RESULT, WE WILL CONTINUE TO CARRY EITHER A LOW OR SLIGHT CHANCE FOR PRECIPITATION. DAYTIME TEMPERATURES ARE ANTICIPATED TO BE WITHIN A FEW DEGREES OF NORMAL FOR THE PERIOD FROM MONDAY NIGHT THROUGH SUNDAY. NIGHTTIME TEMPERATURES ARE FORECAST TO BE SOLIDLY ABOVE NORMAL. && .AVIATION /03Z MONDAY THROUGH FRIDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. OVERNIGHT...VFR CIGS. SOME MVFR CEILINGS AND/OR VISIBILITIES MAY FORM LATE IN THE KABE TO KRDG AREAS BUT THE THICKER UPPER LVL SKY COVER MAY PREVENT THIS FROM HAPPENING. LIGHT WIND. SOME SHOWERS ARE POSSIBLE CLOSER TO DAYBREAK NEARING KILG, HOWEVER CONFIDENCE IS ON THE LOW SIDE. MONDAY...ANY MVFR CONDITIONS SHOULD LIFT EARLY, OTHERWISE MAINLY VFR CIGS. SOME SHOWERS AND THUNDER ARE ANTICIPATED TO DEVELOP KPHL SOUTH AND WEST. SINCE COVERAGE AND OVERALL TIMING IS A BIT UNCERTAIN, USED A VCSH FOR NOW AT INLAND TERMINALS. LIGHT AND VARIABLE WINDS, BECOMING SOUTH-SOUTHEAST UP TO 10 KNOTS. OUTLOOK... MONDAY NIGHT AND TUESDAY MORNING...CONDITIONS POSSIBLY LOWERING TO MVFR OR IFR IN LOW CLOUDS, HAZE AND FOG ESPECIALLY DURING THE LATE NIGHT AND EARLY MORNING HOURS. A CHANCE OF SHOWERS AND THUNDERSTORMS. TUESDAY AFTERNOON AND TUESDAY EVENING...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. TUESDAY NIGHT AND WEDNESDAY MORNING...CONDITIONS POSSIBLY LOWERING TO MVFR OR IFR IN LOW CLOUDS, HAZE AND FOG ESPECIALLY DURING THE LATE NIGHT AND EARLY MORNING HOURS. WEDNESDAY AFTERNOON THROUGH THURSDAY NIGHT...A CHANCE OF SHOWERS AND THUNDERSTORMS WHICH MAY CAUSE CONDITIONS TO LOWER TO MVFR OR IFR AT TIMES. FRIDAY...MAINLY VFR.
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&& .MARINE... NO MARINE HEADLINES ARE ANTICIPATED THRU THE NEAR AND SHORT TERM PDS. OUTLOOK... MONDAY NIGHT THROUGH FRIDAY...NO MARINE HEADLINES ARE ANTICIPATED. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...GORSE/IOVINO NEAR TERM...DRAG/GORSE 1114P SHORT TERM...GORSE/NIERENBERG LONG TERM...IOVINO AVIATION...DRAG/GORSE/IOVINO 1114P MARINE...DRAG/IOVINO/NIERENBERG

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