Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 141903 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 303 PM EDT SUN SEP 14 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD ACROSS THE MID ATLANTIC STATES TODAY, BEFORE MOVING OFFSHORE LATER MONDAY. A COLD FRONT IS THEN EXPECTED TO CROSS THE REGION LATE MONDAY NIGHT INTO EARLY TUESDAY. MORE HIGH PRESSURE WILL BUILD ACROSS THE REGION THROUGH MIDWEEK. A WEAK COLD FRONT MAY PASS THROUGH THE AREA THURSDAY, FOLLOWED BY ANOTHER AREA OF HIGH PRESSURE SETTLING OVER THE REGION FOR FRIDAY INTO SATURDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... REMAINDER OF THE AFTERNOON...CIRRUS NEAR 300MB SPREADS NEWD ACROSS THE AREA AND THICKENS A BIT. TONIGHT...BECOMING CLEAR THIS EVENING WITH LIGHT NORTHWEST OR CALM WIND AND RATHER COOL TEMPS...7 TO 12 DEGREES BELOW NORMAL. IDEAL RADIATIONAL COOLING CONDITIONS. LOWS IN THE 40 TO 45 DEGREE RANGE EXCEPT LOWER 50S URBAN CENTERS AND 45 TO 50 DELMARVA. . THE 12Z/14 50 50 BLENDED NAM/GFS GUIDANCE WAS ALREADY UPDATED INTO THE FCST GRIDS AND WORDING. THE LOW CLOUDINESS YOU SEE EDGING NEWD FROM WVA MAY START SHOWING A SCT-BKN DECK ALONG THE SW EDGE OF OUR FCST AREA NEAR KRDG TOWARD 10Z AS PER THE MORE AGGRESSIVE NAM 1000-850 MB RH BUT THE GFS AND ECMWF ARE SLOWER AND MORE EWD WITH ITS DEVELOPMENT. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... A SUNNY MORNING WITH SOME INCREASING CLOUDS DURING THE LATE AFTERNOON FROM CIRRUS THRU AC AND SC LAYERS. NEAR OR SLIGHTLY BELOW NORMAL TEMPS FOR MID SEPTEMBER. BLENDED 12Z/14 GFS/NAM MOS GUIDANCE WITH LIGHT WINDS TRENDING SW IN THE AFTN EXCEPT SEA BREEZES COAST. EXCEPTION COULD BE MD E SHORE AND SE PA WHERE A DECK OF CLOUDS FROM WVA MAY ARRIVE DURING THE MORNING. NEEDS REEVALUATION OVERNIGHT. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... MONDAY NIGHT, A RATHER QUICK MOVING UPPER SHORTWAVE IS FORECAST TO TRACK EASTWARD FROM AROUND THE GREAT LAKES LATE MONDAY, PASSING OVER OUR REGION INTO EARLY TUESDAY. AN ASSOCIATED WEAK SURFACE LOW AND COLD FRONT IS ALSO PROGGED TO DEVELOP AS THE SHORTWAVE MOVES EAST. OVERALL, THE ECMWF IS A BIT STRONGER WITH THE UPPER SHORTWAVE AND SUBSEQUENT SURFACE LOW AS COMPARED TO THE GFS, WITH POSSIBLY A LITTLE MORE PRECIP AFFECTING OUR REGION FROM LATE MONDAY NIGHT THROUGH TUESDAY MORNING, BUT THE TIMING OF THESE FEATURES IS FAIRLY CONSISTENT BETWEEN THE MODEL GUIDANCE. MOST OF THE SCATTERED SHOWER ACTIVITY SHOULD OCCUR BETWEEN THE 06 TO 12Z TUESDAY TIMEFRAME ACROSS OUR REGION, AND WE HAVE LIKELY POPS IN PLACE FOR THIS PERIOD BEFORE SCALING THEM BACK FROM WEST TO EAST LATER TUESDAY MORNING. BY LATE TUESDAY AFTERNOON INTO TUESDAY EVENING, HIGH PRESSURE FROM ACROSS THE PLAINS AND MIDWEST BEGINS TO EXPAND EASTWARD INTO OUR REGION. FOR THE WEDNESDAY THROUGH SATURDAY TIMEFRAME, OUR REGION WILL MOSTLY BE INFLUENCED BY A LARGE AREA OF SURFACE HIGH PRESSURE AND A BROAD UPPER-LEVEL TROUGH. SOME MODEL GUIDANCE INDICATES A POSSIBLE WEAK COLD FRONT DROPPING INTO THE REGION THURSDAY, BUT THERE IS LITTLE MOISTURE ASSOCIATED WITH THIS BOUNDARY. FOLLOWING THIS DRY COLD FRONT, MORE HIGH PRESSURE TO OUR NORTH CENTERED OVER SOUTHEAST CANADA AND THE NEW ENGLAND STATES WILL SPREAD DOWN INTO THE MID ATLANTIC FRIDAY BEFORE GRADUALLY MOVING OFFSHORE DURING SATURDAY. AT THIS TIME, WE MOSTLY TOOK A WPC/CONTINUITY BLEND, KEEPING A PRECIP-FREE FORECAST THROUGH THIS PERIOD. TEMPERATURES OVERALL LOOK TO BE SLIGHTLY BELOW AVERAGE THROUGH THIS PERIOD, WITH DAYTIME HIGHS RANGING FROM THE 60S IN THE POCONOS AND SURROUNDING AREAS OF NORTHEAST PA AND NORTHWEST NJ TO THE LOWER/MID 70S ELSEWHERE. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THROUGH TONIGHT...VFR WITH ~30000 FT CIRRUS OF VARIABLE THICKNESS SWEEPING NEWD THRU THE AREA THIS EVENING THEN OFF TO THE EAST OF THE COAST BY 02Z/15. LIGHT NORTHWEST OR CALM WIND. SMALL CHANCE PATCHY FOG NEAR SUNRISE IN THE SHELTERED RIVER VALLEYS. ALSO A SMALL CHC OF A 3000 FT DECK OF SC EDGING INTO THE KRDG AREA AROUND 10-12Z BUT LOW PROBABILITY ATTM. MONDAY...VFR DURING THE MORNING WITH MULTI LAYERS AOA 4000 FT ARRIVING LATE IN THE DAY (SC, AC, CI). LIGHT WIND BECOMING SW DURING THE AFTN EXCEPT SE ALONG THE COASTS. ATTM THERE IS A LOW PROBABILITY OF A DECK OF 3000 FT SC DEVELOPING IN SE PA/NE MD SOONER THAN FCST BUT IT DEPENDS ON THE MOVEMENT OF THE CURRENT SC DECK EDGING NEWD FROM WVA. THIS POSSIBILITY WILL BE REEVALUATED OVERNIGHT. OUTLOOK... MONDAY NIGHT THROUGH TUESDAY...MAINLY VFR. SOME SCATTERED SHOWERS ARE POSSIBLE LATE MONDAY NIGHT THROUGH TUESDAY MORNING, WITH SUB- VFR CONDITIONS. WEDNESDAY AND THURSDAY...VFR CONDITIONS ARE EXPECTED. && .MARINE... QUIET THROUGH MONDAY WITH NO HEADLINES. ATLC SEAS GENERALLY AOB 3 FT. DE BAY WAVES MOSTLY 1 FT OR LESS. WINDS VARIABLE ONSHORE LATE THIS AFTERNOON LESS THAN 10 KT BECOMING LIGHT NORTHWEST TONIGHT AND MONDAY MORNING THEN ONSHORE SELY MON AFTN. OUTLOOK... MONDAY NIGHT THROUGH TUESDAY...WHILE A QUICK- MOVING SYSTEM MAY BRING SOME SCATTERED SHOWERS LATE MONDAY NIGHT THROUGH TUESDAY MORNING, WINDS AND SEAS OVERALL LOOK TO REMAIN AT SUB-ADVISORY LEVELS. SOME GUSTS TO AROUND 20 KNOTS POSSIBLE TUESDAY. WEDNESDAY AND THURSDAY...WINDS/GUSTS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA, BUT SEAS MAY BUILD TOWARD 5 FEET, ESPECIALLY FOR OUR OUTER COASTAL WATERS. && .RIP CURRENTS... THERE IS A MODERATE RISK FOR THE FORMATION OF DANGEROUS RIP CURRENTS FOR NJ WITH CONDITIONS IMPROVING LATER TODAY. LOW RISK DE. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...KLINE NEAR TERM...DRAG 302 SHORT TERM...DRAG 302 LONG TERM...KLINE AVIATION...DRAG/KLINE 302 MARINE...DRAG/KLINE 302 RIP CURRENTS...

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