Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 312047 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 447 PM EDT FRI OCT 31 2014 .SYNOPSIS... A SERIES OF LOW PRESSURE AREAS WILL ORGANIZE OFF THE MID ATLANTIC COAST TONIGHT THROUGH SATURDAY NIGHT...AND FINALLY MOVE NORTHEAST INTO THE CANADIAN MARITIMES SUNDAY NIGHT. HIGH PRESSURE WILL MOVE IN FROM THE WEST ON SUNDAY AND CREST OVER THE REGION ON MONDAY. A WARM FRONT WILL CROSS THE REGION ON TUESDAY FOLLOWED BY A COLD FRONT ON THURSDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... THROUGH THIS AFTERNOON...SPRINKLES MAY DEVELOP MONMOUTH/OCEAN COUNTIES...AND BECOME HEAVIER SHOWERS TOWARD 6 PM. WE SEE AN OB OF SPRINKLES AT KWRI BUT UNSURE OF IT. TONIGHT...STRONG 180 M HFC ASSOCIATED WITH CLOSED LOW ALOFT MOVING DOWN INTO GA/SC EARLY SATURDAY WILL PERMIT CONSIDERABLE LIFT TO DEVELOP IN OUR AREA LATE AS VORTICITY ALOFT STRETCHES NORTHWARD. RAIN MAY BE BRIEFLY HEAVY AFTER MIDNIGHT. BOUNDARY LAYER APPEARS TOO WARM FOR SNOW AND SLEET IN THE POCONOS. GUSTY NE WINDS TO 25 MPH DEVELOP MONMOUTH COUNTY COAST AFTER MIDNIGHT. 50 50 BLENDED 12Z NCEP MOS GUIDANCE BUT TRENDED WITH THE SLIGHTLY WARMER GFS MAV DEWPOINTS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... PLENTY OF CYCLONIC MOIST INFLOW AND RATHER UNSTABLE SHOULD WRING OUT PRETTY DECENT PERIODS OF RAIN THROUGH THE MIDDAY HOURS. CHILLY. NOTING LARGE TT OF NEARLY 55C AND SWI -1C AND KI NEAR 29C LOWER PART OF DELMARVA SATURDAY MORNING. COULD BE ISOLATED THUNDER BUT NOT IN GRIDS. TEMPS: LOWERED THE 50 50 BLENDED 12Z NCEP MOS GUIDANCE PER THE 12Z/31 ECMWF AND THE DRIER DEWPOINTS FILTERING SOUTH DURING THE AFTERNOON. GUSTY NORTH WINDS 20-30 MPH...MAY GUST 40 MPH NEAREST 2-5 MILES OF THE COAST BUT NO WIND ADVY ATTM. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
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HIGHLIGHTS... * WINDY WITH UNSEASONABLY COOL TEMPERATURES ON SUNDAY. * FAIR WEATHER MON THRU WED WITH TEMPERATURES MODERATING EACH DAY. * A COLD FRONT IS PROJECTED TO MOVE THROUGH THE REGION ON THURSDAY. OVERVIEW... THE NORTH ATLANTIC OSCILLATION /NAO/ IS PROJECTED TO ENTER A POSITIVE PHASE BEGINNING DURING THE MIDDLE OF THE UPCOMING WEEK. THIS FAVORS A PROGRESSIVE PATTERN WITH ABOVE NORMAL HEIGHTS OVER THE ERN CONUS. AS THE OCEAN LOW IMPACTING THE REGION THIS WEEKEND MOVES INTO THE CANADIAN MARITIMES ON MONDAY...HEIGHTS BEGIN TO BUILD OVER THE ERN CONUS SIGNALING THE RETURN TO A POSITIVE NAO...BUT MODEL DIFFERENCES ARISE IN THE HANDLING OF SHORTWAVE ENERGY ENTERING THE UPPER MS VALLEY BY MID-WEEK. ALTHOUGH THE EURO AND GFS HAVE BEEN IN FAIRLY GOOD AGREEMENT ON THIS FEATURE GOING BACK AT LEAST THREE DAYS... NEITHER MODEL HAS SHOWN RUN-TO-RUN CONSISTENCY AT THIS POINT. THE UNCERTAINTIES IN THE MODEL SOLUTIONS INCREASE BETWEEN 12Z/TUE AND 12Z/THU WITH REGARD TO THE AMPLITUDE AND PLACEMENT OF THE MS VALLEY TROUGH AND THIS WILL HAVE A DIRECT IMPACT THE TIMING OF A COLD FRONT CENTERED AROUND THE THURSDAY TIMEFRAME. THE GEFS INDIVIDUAL ENSEMBLE MEMBERS REPRESENT THIS UNCERTAINTY WELL WITH THEIR PLACEMENT OF THE MID-LEVEL TROUGH AXIS...ONE CAMP CLUSTERING OVER THE MS VALLEY AND THE OTHER CAMP CLUSTERING OVER THE APPALACHIANS. AT THIS POINT... WILL TAKE THE CONSENSUS APPROACH...AND USE THE ENSEMBLE MEAN WHICH IS ALSO IN AGREEMENT WITH CIPS ANALOG GUIDANCE. DAILIES... SUNDAY...THERE IS THE POTENTIAL OF ADVISORY LEVEL WINDS ON SUNDAY AS LOW PRESSURE RAPIDLY DEEPENS EAST OF NEW ENG AND HIGH PRESSURE MOVES INTO THE OHIO VALLEY. MODEL SOUNDINGS INDICATE NORTHWEST WINDS IN THE 40 TO 45 KNOT RANGE AT 850 HPA...AND WITH STEEP LOW-LEVEL LAPSE RATES...WILL BE ABLE TO REALIZE SOME OF THAT MOMENTUM AT THE SURFACE IN GUSTS, ESPECIALLY OVER THE HIGHER TERRAIN, COASTLINE AND OFFSHORE WATERS. THE FLOW ALOFT WILL BE CYCLONIC AND THE COLUMN GRADUALLY DRIES THROUGHOUT THE DAY...AND WITH PVA REMAINING TO THE NORTHEAST AND A STRONG DOWNSLOPING FLOW...NOT EXPECTING ANY PRECIP. TEMPERATURES WILL BE WELL BELOW SEASONABLE LEVELS. MONDAY...THERE WILL STILL BE A TIGHT PRESSURE GRADIENT EARLY IN THE DAY WITH LAPSE RATES INDICATING MOMENTUM TRANSFER TO ABOUT 950 HPA WHERE 25 KNOT WINDS RESIDE. THE WINDS WILL LIGHTEN AS HIGH PRESSURE CRESTS OVER THE REGION LATER IN THE DAY. EXPECTING A DRY DAY WITH TEMPERATURES BELOW SEASONABLE LEVELS. TUESDAY...MID-LEVEL RIDGE CRESTS OVER THE AREA IN CONCERT WITH THE HIGH PRESSURE RIDGE SHIFTING OFFSHORE. THIS MAY ALLOW A WARM FRONT TO MOVE THROUGH THE REGION...BRINGING TEMPERATURES CLOSER TO SEASONABLE LEVELS. WEDNESDAY THROUGH FRIDAY...IF THE PROJECTED FRONTAL PASSAGE TIMING ON THURSDAY HOLDS...WEDNESDAY COULD BE UNSEASONABLY WARM...FOLLOWED BY A RETURN TO MORE SEASONABLE WEATHER ON FRIDAY.
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&& .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. REST OF TODAY...VFR CIGS OVERSPREADING AOA 3500 FT. SPOTTY MVFR CIGS IN NJ. NORTH TO NORTHEAST WIND GUSTS INCREASING TO 15 KT LATE THIS AFTERNOON. TONIGHT...CIGS LOWER TO MVFR CONDS IN PERIODS OF RAIN/DRIZZLE. CHANCE OF IFR CONDS IN NJ. N-NE WIND GUSTS 15-20 KT. CHANCE OF A PERIOD OF HEAVY RAIN AFTER 05Z/01. SATURDAY...MVFR CEILINGS EXPECTED ACROSS THE REGION. LOCALIZED IFR CONDITIONS CLOSER TO THE COAST INCLUDING KACY AND KMIV AND POSSIBLY BACK TO KPHL AND KILG DURING THE MORNING-MIDDAY IN PERIODS OF HEAVIER RAIN. GUSTY NORTH WINDS 20 TO 30 KT. OUTLOOK... SUNDAY...LLWS MAY BE AN ISSUE AT THE TERMINALS DUE TO NORTHWEST WINDS OF 20 TO 30 KNOTS WITH GUSTS TO 40 KNOTS POSSIBLE. OTHERWISE...MAINLY VFR CONDITIONS EXPECTED. MONDAY THROUGH WEDNESDAY...MAINLY VFR CONDITIONS WITH MVFR POSSIBLE WITH THE PASSAGE OF A WARM FRONT ON TUESDAY.
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&& .MARINE... TONIGHT...SCA N-NE WIND CONDITIONS DEVELOP BUT THE HEADLINE IS SUPERSEDED BY TOMORROWS GALE WARNING. SATURDAY...GALE CONDITIONS EXPECTED ALL WATERS BY 6PM SATURDAY WITH VARIOUS STARTING TIMES. AT THIS TIME IT LOOKS LIKE MARGINAL GALE BEGINS VICINITY 44065 (NNJ WATERS) NEAR DAYBREAK SATURDAY AND THEN SPREADS SOUTHWARD DURING THE DAY WITH GUSTS INCREASING 5 KT EVERYWHERE DURING THE AFTERNOON. WE MAY SEE SPOTTY GALE GUSTS DURING THE LATE MORNING EVEN IN DELAWARE BAY. GALE WATCH UPPER DE BAY CHANGED TO A WARNING AT THE 330 PM ISSUANCE. OUTLOOK... SATURDAY NIGHT THROUGH SUNDAY NIGHT...GALE CONDITIONS EXPECTED ON THE ATLANTIC WATERS AND DELAWARE BAY WITH PEAK GUSTS NEAR 45 KT. SEAS AS HIGH AS 10FT POSSIBLE ON THE ATLANTIC WATERS. MONDAY...SCA MAY BE NEEDED FOR BOTH WINDS AND SEAS. TUESDAY AND WEDNESDAY...A WARM FRONT MAY MOVE OVER THE WATERS ON TUESDAY...EXPECTING WINDS AND SEAS TO REMAIN BELOW SCA THRESHOLDS DURING THIS TIMEFRAME. && .TIDES/COASTAL FLOODING... A STRONG NORTHEAST FLOW ASSOCIATED WITH THE STRENGTHENING LOW PRESSURE SYSTEM OFF THE EAST COAST WILL PRODUCE ELEVATED WATER LEVELS DOWN THE SHORE THROUGH THE WEEKEND. CURRENT GUIDANCE SUGGESTS MINOR TIDAL FLOODING ALONG BOTH THE NEW JERSEY AND DELAWARE COASTS FOR SATURDAY AFTERNOON/S HIGH TIDE...AND PERHAPS AGAIN AT THE TIME OF HIGH TIDE EARLY SUNDAY MORNING. TOTAL WATER LEVELS (ASTRONOMICAL TIDE PLUS THE POSITIVE ANOMALIES CAUSED BY THE STORM) FROM ATLANTIC CITY SOUTH THROUGH LEWES DE HAVE A GOOD PROBABILITY OF BEING HIGH ENOUGH DURING SATURDAY AFTERNOON/S HIGH TIDE TO WARRANT AN ADVISORY STATEMENT...SO ONE HAS BEEN ISSUED. RIGHT NOW CURRENT GUIDANCE SUGGESTS THAT WHILE MINOR TIDAL FLOODING IS EXPECTED IN MIDDLESEX...MONMOUTH...AND OCEAN COUNTIES...TOTAL WATER LEVELS WILL PEAK JUST SHORT OF ADVISORY LEVEL CRITERIA. THIS COULD BE A CLOSE CALL, SO RESIDENTS ALONG THE COAST SHOULD KEEP ABREAST OF UPDATED FORECASTS AND ADVISORIES AS THIS EVENT UNFOLDS. RIGHT NOW ELEVATED WATER LEVELS ARE ALSO EXPECTED IN THE DELAWARE BAY, WITH POCKETS OF MINOR TIDAL FLOODING POSSIBLE AT THE TIME OF HIGH TIDE SATURDAY AFTERNOON AND EVENING UP THROUGH REEDY POINT. NO FLOODING IS EXPECTED AT THIS TIME IN THE TIDAL PORTIONS OF THE DELAWARE RIVER...INCLUDING PHILADELPHIA. NO PROBLEMS ARE CURRENTLY EXPECTED ALONG THE SHORES OF THE CHESAPEAKE BAY AFFECTING THE MIDDLE AND UPPER PORTIONS OF THE MARYLAND EASTERN SHORE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...COASTAL FLOOD ADVISORY FROM 1 PM TO 7 PM EDT SATURDAY FOR NJZ022>025. DE...COASTAL FLOOD ADVISORY FROM 1 PM TO 7 PM EDT SATURDAY FOR DEZ003-004. MD...NONE. MARINE...GALE WARNING FROM 6 AM EDT SATURDAY TO 5 PM EST SUNDAY FOR ANZ450>453. GALE WARNING FROM NOON EDT SATURDAY TO 5 PM EST SUNDAY FOR ANZ430-431-454-455. && $$ SYNOPSIS...FRANCK NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...FRANCK AVIATION...DRAG/FRANCK MARINE...DRAG/FRANCK TIDES/COASTAL FLOODING...

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