Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 231321 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 921 AM EDT SUN AUG 23 2015 .SYNOPSIS... A WEAKENING RIDGE OF HIGH PRESSURE WILL PREVAIL FROM NEW ENGLAND TO THE MID ATLANTIC STATES THROUGH TONIGHT. MEANWHILE, A FRONTAL BOUNDARY CONTINUES TO MEANDER AND WEAKEN OFFSHORE. A COLD FRONT IS EXPECTED TO ARRIVE MONDAY NIGHT WITH LOW PRESSURE FORMING ON IT OVER NEW JERSEY. THEREAFTER, THE FRONT SLIPS EVER SO SLOWLY OFF THE COAST DURING MID WEEK. HIGH PRESSURE IS EXPECTED TO FOLLOW FOR THE END OF THE WEEK INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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THE SAFETY SQUEEZE PLAY IS ON TODAY WITH OFFSHORE LOW PRESSURE TO OUR EAST AND COLD FRONT WAY BACK TO OUR WEST. WE ARE STUCK IN BETWEEN WITH HIGH PRESSURE BEING FORCED UP TO OUR NORTH BUT WE SHOULD STILL REAP THE REWARDS FOR HAVING THE HIGH PRESSURE NEARBY...LOWER HUMIDITY AND A MOSTLY RAIN FREE DAY. NOT COMPLETELY SOLD ON THE NOTION THAT OUR EASTERN ZONES WILL SEE SHOWER ACTIVITY TODAY AS MOISTURE TRIES TO PUSH ONSHORE WHILE BEING SPUN AROUND THE LOW PRESSURE TO OUR EAST. MOST OF THE HI-RES AND CONVECTIVE ALLOWING MODELS KEEP THE ACTIVITY TO AN ABSOLUTE MINIMUM, IF ANY AT ALL, AND CONFINED TO THE EXTREME NORTHEAST NEW JERSEY AREA. WE DID SCALE BACK HE AREAL EXTENT OF OUR PESSIMISTIC SLIGHT CHANCE POPS THIS AFTERNOON. THE COLUMN REMAINS RELATIVELY DRY, FOR LATE AUGUST, WHILE A THIN LAYER OF HIGHER RELATIVE HUMIDITY TRIES TO ADVECT IN FROM THE EAST...THIS LAYER IS RIGHT AROUND 850MB. EXPECTING A BROKEN DECK STRATO-CU TO WORK IN FROM THE EAST THIS AFTERNOON BUT SHOULD BEGIN TO SCATTER OUT BY LATE AFTERNOON. WINDS TODAY WILL BE STRONGEST IN THE MORNING BEFORE THE PRESSURE GRADIENT REALLY SLACKENS, WITH HIGH PRESSURE CRESTING OVERHEAD, MAKING FOR EITHER CALM OR LIGHT AND VARIABLE CONDITIONS. SEA AND BAY BREEZES SHOULD HAVE A PRETTY EASY TIME PUSHING INLAND WITH LITTLE TO NO RESISTANCE AS TEMPERATURES CLIMB INTO THE LOW TO MID-80S. FOR THE MRNG UPDATE, RAISED TEMPS IN THE REAL NR TERM AS THEY HAVE RESPONDED MORE QUICKLY THAN EARLIER THOUGHT, THOUGH HIGH TEMPS FOR THE DAY STILL LOOK GOOD. OTHERWISE, ADJUSTED CLOUDS A BIT.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... COULD SEE A RE-TIGHTENING OF THE PRESSURE GRADIENT, THOUGH THAT IS PROBABLY A STRETCH, WITH WINDS VEERING MORE TOWARDS THE SOUTH- SOUTHWEST AHEAD OF THE APPROACHING COLD BEFORE DECOUPLING AGAIN. SKIES SHOULD CLEAR TONIGHT BEFORE A MID-LEVEL DECK PUSHES IN FROM THE WEST-SOUTHWEST AS A COMPLEX OF STORMS MOVES BY WELL TO OUR SOUTHWEST...CLOSER TOWARDS DAYBREAK ON MONDAY. BLEND OF MAV/MET LOOKED GOOD FOR OVERNIGHT LOWS TONIGHT WITH SOME MINOR ADJUSTMENTS ACROSS THE PINE BARRENS AND NORTHERN NEW JERSEY. && .LONG TERM /MONDAY THROUGH SATURDAY/... 500 MB: A TROUGH FROM THE GREAT LAKES TO THE APPALACHIANS SLOWLY AMPLIFIES ALONG THE APPALACHIANS EARLY THIS WEEK, THEN WEAKENS TOWARD NEXT WEEKEND, LEAVING A PIECE OF THE TROUGH BEHIND OVER THE SOUTHEAST USA. TEMPERATURES: CALENDAR DAY AVERAGES NEAR 5 DEGREES ABOVE NORMAL MONDAY AND TUESDAY, NEAR NORMAL THE REST OF THE WEEK. FORECAST BASIS: UNLESS OTHERWISE NOTED, A 50 50 BLEND 00Z/23 GFS/NAM MOS GUIDANCE MONDAY-TUESDAY, 00Z/23 MEX MOS TUESDAY NIGHT AND WEDNESDAY, THEN THE 0441Z/23 WPC GRIDDED ELEMENTS OF MAX/MIN TEMP, 12 HOUR POP, 6 HOUR DEWPOINT-SKY-WIND FROM WEDNESDAY NIGHT THROUGH NEXT SATURDAY. THE DAILIES... MONDAY...APPROACHING COLD FRONT WILL PRODUCE SCT SHOWERS/TSTMS LATE IN THE DAY OR MORE LIKELY AT NIGHT BUT NOT BEFORE AROUND 90F FOR A MAX TEMP...ABOVE NORMAL. 22/21Z SREF MODELED PWAT INCREASES CONSIDERABLY FROM THE SW TO 1.5 INCHES BY DAYS END I-95 SEWD. SOUTH TO SOUTHWEST WIND GUSTY 15 MPH. ONLY 400J MLCAPE LATE DAY. DURING THE DAY, THE SHOWER THREAT SHOULD BE CONFINED TO THE REGION ABOUT 20 TO 30 MILES NORTHWEST OF OF KILG-KPHL-KSMQ. 00Z/23 MAV AND MET WERE VIRTUALLY IDENTICAL ON MAX`S. RAISED THAT GUIDANCE BY 2F PER 87.5 2M TEMPS OF THE GFS AND 85-86F ON THE ECMWF AND NOT MUCH CLOUD COVER DURING THE DAYLIGHT HOURS (RELATIVELY LOW DEWPOINTS) CONFIDENCE: ABOVE AVERAGE. MONDAY NIGHT...WAA CONTINUES WITH LOW PRESSURE ON THE FRONT PRODUCING AN EXPANDING AREA OF SHOWERS...PROBABLY NEAR OR JUST EAST OF I-95. MODEL INSTABILITY INCREASES THROUGH THE NIGHT AND A THE 700MB FLOW DEVELOPS A SPEED MAX CORE OVER OUR AREA. SOME OF THE RAIN I-95 EWD COULD BE BRIEFLY HEAVY. FORECAST ELEMENTS WERE 50 50 BLENDED 00Z/23 GFS/NAM MOS. CONFIDENCE: ABOVE AVERAGE (USED 06Z WPC QPF). TUESDAY...MAYBE LINGERING SHOWERS JUST E OF I-95? OTHERWISE BECOMING M/S AND WARM DURING MIDDAY. SREF PWAT TO START THE DAY DOWN TO 1.1 INCHES I-95 CORRIDOR, LESS TO THE WEST. WINDS TURN WESTERLY AND GUST TO 15 MPH DURING THE AFTERNOON. CONFIDENCE:ABOVE AVERAGE. WED-FRI...DIURNAL CU/SC AS A COOL POOL ARRIVES WITH THE TROUGHING ALOFT AND TEMPS SEASONABLY COOL. MLCAPE ALMOST NIL. SOME INSTABILITY CROSSES NORTHERN PA AND EXTREME NW NJ WEDNESDAY AFTERNOON/EVENING WITH KI IN THE MID 20S AND A 500 MB VT MAX. CALLED IT SPRINKLES (BIG DROP) WITH SHALLOW DEVELOPMENT OF THE CU FIELDS-BELOW 15,000 FT. SAT...P OR M/S. WAA CLOUDINESS PROBABLY DEVELOPS AS THE KI INCREASES. STARTING A WARMING TREND THAT APPEARS TO HAVE A CHANCE TO CONTINUE THROUGH THE 31ST AND OF COURSE MORE 90F HEAT BEYOND THIS 7 DAY FCST PERIOD. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. TODAY...MOSTLY VFR. NORTHERLY WINDS THROUGH THE EARLY AFTERNOON BEFORE THE PRESSURE GRADIENT REALLY WEAKENS AND WINDS BECOME LIGHT AND VARIABLE, POSSIBLY CALM AT MOST TERMINALS. THE WEAK SURFACE FLOW SHOULD ALLOW FOR SEA AND BAY BREEZE CIRCULATIONS AT KACY/KILG WITH WINDS VEERING TOWARDS THE SOUTHEAST. MARINE STRATUS, SHOULD BE VFR, MOVES FARTHER INLAND THIS AFTERNOON AROUND 4-5KFT BEFORE SCATTERING OUT LATE. TEMPORARY MVFR DECK POSSIBLE AT KACY. TONIGHT...VFR. WINDS SHOULD BE OUT OF THE SOUTH-SOUTHWEST AHEAD OF AN APPROACHING COLD FRONT MOVING IN FROM THE WEST. THE SHELTERED TERMINALS SHOULD GO CALM AGAIN. OUTLOOK... MONDAY...VFR SCT-BKN AOA 5000 FT. A CHANCE OF LATE AFTERNOON SHOWERS AND THUNDERSTORMS VCNTY KRDG AND KABE. S-SW WIND SHOULD GUST NEAR 15 KT IN THE AFTERNOON. CONFIDENCE: ABOVE AVERAGE. MONDAY NIGHT...SCATTERED SHOWERS AND THUNDERSTORMS SHOULD BECOME MORE WIDESPREAD IN COVERAGE AS THEY SPREAD INTO NORTHEAST NJ LATE AT NIGHT. BRIEF MVFR OR IFR CATEGORIES POSSIBLE IN HEAVIER SHOWERS. CONFIDENCE: ABOVE AVERAGE. TUESDAY...A CHANCE OF SHOWERS EARLY OTHERWISE A VFR DAY WITH A CLEARING TREND. THE WIND SHOULD BECOME WESTERLY WITH AFTERNOON GUSTS NEAR 15 KT. CONFIDENCE: AVERAGE. TUESDAY NIGHT...MAINLY VFR WITH PATCHY LOW CLOUDS AND FOG POSSIBLE AFTER 06Z/26, MAINLY THE COUNTRYSIDE OF NEW JERSEY. CONFIDENCE: BELOW AVERAGE ON LOW CLOUDS/FOG. WEDNESDAY THROUGH THURSDAY...MAINLY VFR WITH SCT CLOUDS AOA 5000 FT WHICH MAY BE BRIEFLY BROKEN EACH AFTERNOON. CONFIDENCE: ABOVE AVERAGE.
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&& .MARINE... TODAY - TONIGHT...SUB-SCA. WINDS OUT OF THE NORTH-NORTHEAST EARLY BEFORE VEERING MORE EASTERLY BY THE EARLY AFTERNOON HOURS...AROUND 10 KNOTS TODAY. SEA BREEZE EXPECTED THIS AFTERNOON ALONG BOTH NJ AND DELAWARE COASTS AS WINDS VEER MORE SOUTHEAST AND FUNNEL UP THE LOWER BAY A BIT...AROUND 10 KNOTS. SEAS ACROSS THE NORTHERN WATERS ARE EXPECTED TO RUN AROUND 3 FEET TODAY WHILE THE SOUTHERN WATERS MAY APPROACH 4 FEET BY THE AFTERNOON WITH THE LONGER NORTHEASTERLY FETCH. WINDS VEER A BIT MORE TOWARDS THE SOUTHWEST BUT WILL BE VERY LIGHT. OUTLOOK... MONDAY THROUGH THURSDAY...NO MARINE HEADLINES ARE ANTICIPATED. STILL MARINERS SHOULD BE AWARE THAT A 3 FOOT 8 SECOND NORTHEAST SWELL SHOULD DEVELOP LATER TODAY AND PERSIST INTO MONDAY. THEREAFTER A LONGER PERIOD 2 FOOT SOUTHEAST SWELL SHOULD DOMINATE THE ATLANTIC WATERS TUESDAY THROUGH THURSDAY. SST`S ARE GENERALLY SEVERAL DEGREES ABOVE NORMAL. && .RIP CURRENTS... THE WEEK PROJECTS LOW/LOW ENHANCED EVERY DAY THROUGH THURSDAY. AM ALWAYS CAUTIOUS WHENEVER SWELLS WITH A PERIOD LONGER THAN 10 SECONDS OCCUR. ESSENTIALLY, A NORTHEAST 3 FOOT 8 SECOND SWELL ASSOCIATED WITH THE SURFACE LOW WELL SE OF CAPE COD SHOULD ARRIVE HERE LATER TODAY AND PERSIST INTO MONDAY. FROM TUESDAY THROUGH THURSDAY THE GFS INDICATES A SE SWELL OF 2 FEET 10-11 SECONDS, STILL A LOW RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS. WATER TEMPERATURES ARE GENERALLY SEVERAL DEGREES ABOVE NORMAL. && .CLIMATE...
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MORE 90 DEGREE HEAT IS EXPECTED BETWEEN MONDAY AND THE END OF AUGUST (1 TO 4 DAYS). SEASONAL 90 DEGREE DAYS. POR MEAN 2015 2014 ABE: 1922 17 12 10 ACY: 1874 10 16 8 ILG: 1917 20 11 13 PHL: 1873 21 28 19
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&& .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...DRAG NEAR TERM...HEAVENER/NIERENBERG SHORT TERM...HEAVENER LONG TERM...DRAG AVIATION...DRAG/HEAVENER MARINE...DRAG/HEAVENER RIP CURRENTS... CLIMATE...

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