Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 270925 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 525 AM EDT MON APR 27 2015 .SYNOPSIS... A LARGE BLUSTERY LOW PRESSURE SYSTEM OVER THE WESTERN NORTH ATLANTIC WILL MOVE SLOWLY OUT TO SEA LATER TUESDAY. THEN WET LOW PRESSURE OVER THE SOUTHEASTERN UNITED STATES WEDNESDAY WILL INTENSIFY AS IT PLODS NORTHWARD ALONG THE MID ATLANTIC COAST LATER THURSDAY AND THEN SEAWARD JUST SOUTHEAST OF NANTUCKET FRIDAY NIGHT. HIGH PRESSURE IS EXPECTED TO BUILD SOUTH OF OUR REGION BY SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AN UPPER TROUGH ACROSS NEW ENGLAND AND UPSTATE NY EARLY THIS MORNING WILL MOVE SOUTHWARD ACROSS OUR REGION THIS AFTERNOON. THE FEATURE WILL BRING MOSTLY CLOUDY SKIES ACROSS MUCH OF THE REGION TODAY. THERE IS A SLGT CHC FOR A SHOWER THIS AFTERNOON...BUT WE WILL KEEP POPS ONLY AROUND 20 PCT...SINCE THE AIRMASS REMAINS RATHER DRY. TEMPERATURES TODAY WILL REMAIN A LITTLE BELOW NORMAL WITH HIGHS ONLY TOPPING OUT IN THE 50S FAR NORTH AND LOW 60S ELSEWHERE. WINDS WILL BE NORTHWEST AT 5 TO 10 MPH THIS MORNING...THEN INCREASE TO 10 TO 15 MPH WITH GUSTS AROUND 20 MPH THIS AFTERNOON. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... THE UPPER TROUGH WILL BE ACROSS THE SOUTHERN PARTS OF THE CWA AND IT WILL CONTINUE TO PIVOT AWAY FROM THE AREA. ANY SCT SHOWERS FROM THE LATE AFTERNOON WILL DIMINISH DURING THE EVENING WITH THE 20 POP CARRYING IN THE EVENING. CLOUDS WILL CONTINUE TO CIRCULATE ACROSS THE AREA...WITH A TREND TOWARD FEWER CLOUDS BY DAYBREAK TUE. LOWS TONIGHT WILL BE IN THE UPPER 30S TO LOW 40S NORTH AND LOW/MID 40S ELSEWHERE. WINDS WILL BE MODERATE...FROM THE NW 10 TO 15 MPH. && .LONG TERM /TUESDAY THROUGH SUNDAY/... **WIND SWEPT SOAKING RAINS MAY BE ON THE WAY HERE THURSDAY- FRIDAY** 500 MB: BELOW NORMAL HEIGHTS DOMINATE OUR AREA THROUGH SATURDAY MORNING THEN A WARMING RIDGE DEVELOPS HERE SUNDAY. THE LARGE CLOSED LOW IN THE WESTERN ATLANTIC SOUTH OF NOVA SCOTIA TUESDAY WEAKENS EASTWARD DURING MID WEEK. MEANWHILE A STRONG SOUTHERN USA SHORT WAVE ON WEDNESDAY HAS A GOOD CHANCE OF BEING SCOOPED NORTHWARD BY A SOUTH CENTRAL CANADA SHORT WAVE DIVING SOUTHWARD ALONG 83 DEGREES WEST LONGITUDE. THE TWO SHOULD PHASE INTO A NEW ROBUST CLOSED LOW ALONG OR EAST OF THE MID ATLANTIC COAST FRIDAY. TEMPERATURES: CALENDAR DAY AVERAGES AROUND 3 DEGREES BELOW NORMAL TUESDAY THEN NEAR OR SOMEWHAT BELOW NORMAL WEDNESDAY - SATURDAY, WITH A DEFINITE WARMING TREND TO FOLLOW NEXT SUNDAY! HAZARDS THIS 6 DAY PERIOD: FIRE WEATHER IS A POSSIBLE CONSIDERATION PRIOR TO THURSDAY. THURSDAY-FRIDAY IS UNCERTAIN BUT MINOR HYDRO AND WIND ISSUES MAY DEVELOP? FORECAST BASIS: UNLESS OTHERWISE NOTED, A 50 50 BLEND 00Z/27 GFS/NAM MOS GUIDANCE TUESDAY-WEDNESDAY, 00Z/27 MEX MOS WEDNESDAY NIGHT AND THURSDAY, THEN THE 0541Z/27 WPC GRIDDED ELEMENTS OF MAX/MIN TEMP, 12 HOUR POP, 6 HOUR DEWPOINT-SKY-WIND FROM THURSDAY THROUGH NEXT SATURDAY. THE DAILIES... TUESDAY...MOSTLY SUNNY MORNING, CONSIDERABLE CLOUDINESS AFTERNOON. A GUSTY NNW WIND TO 20-25 MPH. CLEAR AT NIGHT. CONFIDENCE: ABOVE AVERAGE. WEDNESDAY...SUNNY (CIRRUS ARRIVES LATE DAY?) LIGHT NW-W WIND BUT CHILLING AFTERNOON SEA BREEZES COASTS CONFIDENCE: ABOVE AVERAGE THURSDAY...MOSTLY CLOUDY. EAST WIND, POSSIBLY GUSTY 20-30 MPH BY LATE IN THE DAY. PERIODS OF RAIN LIKELY, POSSIBLY POCKETS OF HEAVY. SMALL CHC OF A GUSTY TSTM SOUTHERN DE LATE THURSDAY NIGHT WHERE 00Z/27 GFS MODELS TT 55+, SWI -2 AND 40-50 KT 850 INFLOW. TEMPERATURE GUIDANCE WAS UNDERCUT BY 4 DEGREES THURSDAY AND THURSDAY NIGHT. THE GEFS IS BECOMING EVER MORE ROBUST WITH THIS SYSTEM WHILE THE EURO REMAINS JUST OFFSHORE. UNLESS THE GEFS STARTS BACKING DOWN, THINK WE NEED TO BE THINKING OF A DECENT STORM. STILL EARLY. 00Z/27 GEFS HAS A 20-30 PCT 48 HR PROB OF 2" IN PARTS OF OUR AREA AND WIDESPREAD 48 HR 1 INCH AMTS. 850-925 MB ENE INFLOW IS ABOUT 3 OR 4 SD DEVIATIONS ABOVE NORMAL. IF THE PHASE OCCURS - THIS SHOULD BE QUITE A PCPN PRODUCER. 00Z NAEFS HAS SIGNIFICANT QPF AS WELL, AMOUNTS EXCEEDING 1/2 INCH, ESPECIALLY S NJ SE PA SOUTHWARD. CONFIDENCE: BELOW AVERAGE DUE TO COASTAL STORM TRACK UNCERTAINTY. FRIDAY...MORNING RAIN THEN CONSIDERABLE CLOUDINESS AND BLUSTERY NORTH-NORTHWEST WINDS 25-35 MPH. RIGHT NOW OUR GRIDDED WIND FORECAST LOOKS FAR TOO LOW. GUIDANCE TEMPERATURES LOWERED SEVERAL DEGREES. OVERALL CONFIDENCE: BELOW AVERAGE DUE TO UNCERTAIN PROXIMITY OF THE COASTAL STORM. SURGE WILL NEED TO EXCEED 2 FEET BEFORE ITS A MINOR COASTAL FLOOD PROBLEM,. RIGHT NOW GUIDANCE IS 1 TO 2 ABOVE NORMAL AT THE TIME OF THE EVENING HIGH TIDES THU/FRI. SATURDAY...PARTLY TO MOSTLY SUNNY. NORTHWEST WIND GUSTS 15-20 MPH. CONFIDENCE: BELOW AVERAGE DUE TO UNCERTAIN PROXIMITY OF THE DEPARTING COASTAL LOW. SUNDAY...PARTLY TO MOSTLY SUNNY. MILDER. LIGHT WIND. CONFIDENCE: AVERAGE. OUTLOOK: A SUBSTANTIAL RIDGE FROM THE WEST IS FORECAST TO BUILD OVER THE EASTERN STATES FOR THE FIRST FULL WEEK OF MAY. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. WE ARE CONTINUING THE VFR TAFS FOR ALL SITES TODAY AND TONIGHT. AN UPPER TROUGH AND A FEW EMBEDDED VORT MAXS WILL CROSS THE REGION TODAY MOVING BASICALLY N TO S. A SHIELD OF CLOUDS ACROSS NRN PA WILL PROGRESS SOUTHWARD EARLY TODAY AND WILL BRING BKN MID LEVEL CLOUDINESS EARLY TODAY. LATER TODAY...DAYTIME CU/SC AND MORE AC WILL AFFECT THE REGION. THERE IS A VERY SMALL POSSIBILITY FOR A SHOWER...BUT NONE WERE INSERTED IN THE TAFS WITH LOW CONFID IN TIMING/LOCATION. WINDS WILL BE MOSTLY NW AT 5 TO 10 KNOTS EARLY...THEN PICKUP IN SPEEDS WITH SOME AROUND 20 KNOTS THIS AFTERNOON. SCT-BKN CLOUDINESS TONIGHT WITH MODERATE NW WINDS CONTINUING. OUTLOOK... TUESDAY...VFR WITH PREDOMINANCE BKN CLOUDS AOA 5000 FT MIDDAY- AFTERNOON. NNW WIND GUSTY TO 20-25 KT DIMINISHES TO LIGHT AT NIGHT. CONFIDENCE: ABOVE AVERAGE. WEDNESDAY...VFR CLEAR WITH CIRRUS ARRIVING LATE IN THE DAY. W-NW WIND GUSTS AOB 15 KT DURING THE DAY AND LIGHT AT NIGHT. CONFIDENCE: ABOVE AVERAGE. THURSDAY AND THURSDAY NIGHT...VFR CIGS OCNL MVFR OR IFR CONDS IN RAIN. CHANCE OF A TSTM DELAWARE THU NIGHT? EAST TO NORTHEAST WIND MAY GUST 20-30 KT LATE THU. PROBABLE IMPACT ON OPERATIONS AT KPHL. DETAIL CONFIDENCE: BELOW AVERAGE DUE TO UNCERTAIN PROXIMITY OF THE COASTAL STORM. FRIDAY...BLUSTERY. MORNING RAIN? OTHERWISE MAINLY VFR CIGS CLEARING AT NIGHT. N-NW WIND GUSTS 25-35KT. DETAIL CONFIDENCE: BELOW AVERAGE. && .MARINE... WINDS AND SEAS WILL REMAIN BELOW SCA CONDITIONS TODAY. AN UPPER TROUGH WILL MOVE ACROSS THE AREA...THEN SOME COOLER AIR AND SFC GUSTINESS WILL BRING LOW-END SCA GUSTS TO THE WATERS TONIGHT. THE ONGOING 00Z/TUE START TIME STILL LOOKS GOOD AT THIS POINT...SO NO CHANGES WILL BE MADE. MOSTLY FAIR WEATHER TODAY WITH ONLY A SLGT CHC OR A SHOWER THIS AFTERNOON AND EARLY THIS EVENING. OUTLOOK... TUESDAY MORNING...A SMALL CRAFT ADVISORY IS IN EFFECT FOR A NORTHWEST TO NORTH WIND GUSTING TO 25 OR 30 KNOTS. CONFIDENCE: ABOVE AVERAGE. TUESDAY AFTERNOON THROUGH THURSDAY MORNING...NO MARINE HEADLINES ARE ANTICIPATED. CONFIDENCE: ABOVE AVERAGE. THURSDAY AFTERNOON THROUGH FRIDAY...A SMALL CRAFT ADVISORY FOR SURE FOR NE WIND GUSTS OF 25 TO 30 KNOTS BACKING TO N OR NW FRIDAY AND FOR WAVES ON OUR OCEAN WATERS WELL IN EXCESS OF 5 FEET. THERE IS INCREASING POTENTIAL FOR GALE FORCE 35 TO 45 KT GUSTS LATE THURSDAY OR FRIDAY MORNING BUT TRACK CONFIDENCE IS BELOW AVERAGE. CONFIDENCE ON A HEADLINE MARINE EVENT IS WELL ABOVE AVERAGE. && .FIRE WEATHER... NORTH-NORTHWEST WIND GUSTS OF 20 TO POSSIBLY 25 MPH ARE EXPECTED TUESDAY AS RELATIVE HUMIDITY VALUES DROP AROUND 30 PERCENT IN MUCH OF OUR REGION TUESDAY AFTERNOON. FURTHER DAYTIME EVALUATION AND POSSIBLE PARTNER DISCUSSIONS MAY EVENTUALLY REQUIRE A SPECIAL WEATHER STATEMENT HIGHLIGHTING MARGINAL MORE RAPID RATE OF SPREAD CONDITIONS TUESDAY AFTERNOON. RH WEDNESDAY AFTERNOON ABOUT THE SAME OR POSSIBLY SLIGHTLY LOWER BUT WIND GUSTS ARE LESS THAN 18 MPH. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO NOON EDT TUESDAY FOR ANZ430-431-450>455. && $$ SYNOPSIS...DRAG NEAR TERM...O`HARA SHORT TERM...O`HARA LONG TERM...DRAG 523 AVIATION...DRAG/O`HARA 523 MARINE...DRAG/O`HARA FIRE WEATHER...

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