Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 231001 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 601 AM EDT TUE SEP 23 2014 .SYNOPSIS... A HIGH WILL SLIDE EAST OVER THE REGION TODAY AND TONIGHT. TOMORROW, A LOW IS EXPECTED TO DEVELOP OFF THE CAROLINA COAST BEFORE LIFTING NORTHEAST INTO DELMARVA RESULTING IN INCREASED RAIN CHANCES THROUGH THURSDAY NIGHT. A HIGH CENTERED OVER THE GREAT LAKES REGION WILL BUILD BY FRIDAY BRINGING A RETURN OF TRANQUIL WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH PRESSURE WILL SLIDE ACROSS THE AREA TODAY WHICH WILL KEEP THE WEATHER QUIET. THERE IS LITTLE IN THE WAY OF LOW OR MID LEVEL MOISTURE FORECAST TODAY, SO WE DO NOT EXPECT MUCH THICK CLOUD COVER TODAY. WE ONLY EXPECT HIGH LEVEL CIRRUS ACROSS THE AREA AS THE UPPER JET WILL KEEP A STREAM OF UPPER LEVEL MOISTURE ACROSS THE AREA. HIGHS TODAY ARE A BLEND OF MIXED 925MB ECMWF TEMPS, MAV/MET MOS, AND MOSGUIDE WHICH KEEPS EVERYONE SLIGHTLY BELOW OR RIGHT AROUND NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... HIGH PRESSURE WILL SLIDE INTO NEW ENGLAND OVERNIGHT, BUT STILL NOSE DOWN INTO THE MID-ATLANTIC AND KEEP FAIR WEATHER ACROSS OUR AREA. THE ONLY CLOUDS WE EXPECT WILL BE THE CONTINUING HIGH LEVEL CIRRUS OVERHEAD WHICH WILL NOT HAVE MUCH OF AN EFFECT ON THE WEATHER. OVERNIGHT LOWS ARE A BLEND OF MAV/MET MOS AND MOSGUIDE WHICH KEEPS EVERYONE PRETTY CLOSE TO NORMAL. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... MOST OF THE ATTENTION THROUGH THESE PERIODS IS FOCUSED ON WEDNESDAY AND THURSDAY. MODELS TRENDED A BIT FURTHER NORTH WITH THE TRACK OF THE SURFACE LOW. HOWEVER, THERE REMAIN SOME SIGNIFICANT DIFFERENCES BETWEEN THE MODELS ON THE INTENSITY OF THE LOW. THE GFS BY FAR IS SHOWING THE MOST AND FASTEST CYCLOGENESIS, WHICH WOULD MEAN MORE IMPACTS ESPECIALLY ON OUR SOUTHERN COASTAL AND MARINE ZONES. HOWEVER, WITH THE UPPER LEVEL TROUGH FILLING AND LIFTING THROUGH THIS PERIOD, WOULD NOT EXPECT THE PATTERN TO SUPPORT SUCH RAPID CYCLOGENESIS. THUS FORECAST FAVORS THE ECMWF SOLUTION, SHOWING INSTEAD AN OPEN INVERTED SURFACE TROUGH. HOWEVER, EVEN WITH THIS SOLUTION, THE FURTHER NORTH TRACK COULD MEAN MORE WIDESPREAD PRECIPITATION, THUS HAVE INCREASED POPS ACROSS THE REGION, ALTHOUGH DE AND SOUTHERN NJ ARE STILL THE FAVORED AREAS FOR RAIN. FRIDAY THROUGH SUNDAY...AT THE SURFACE, A HIGH WILL BUILD IN OVER THE GREAT LAKES REGION. AT THE SAME TIME IN THE UPPER LEVELS, A VERY HIGH AMPLITUDE RIDGE WILL DEVELOP AND SLIDE EAST. THUS EXPECT A RETURN TO TRANQUIL WEATHER. HOWEVER, WITH THE CENTER OF THE SURFACE HIGH REMAINING NORTH OF THE REGION, WE SHOULD KEEP LOW LEVEL EASTERLY FLOW, WHICH MAY SLIGHTLY TEMPER THE WARMING TREND. MONDAY INTO TUESDAY...STILL CONSIDERABLE UNCERTAINTY WITH THE TRACK AND TIMING OF A STRONG COLD FRONT. GIVEN THE STOUT HIGH THAT WILL ALREADY BE IN PLACE, IT IS UNCERTAIN IF THE FRONT WILL BE ABLE TO PROPAGATE THIS FAR SOUTH. THUS...HAVE KEPT CLOSE TO THE PREVIOUS FORECAST FOR NOW. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD AS HIGH PRESSURE BUILDS ACROSS THE AREA. WE ONLY EXPECT HIGH LEVEL CIRRUS THROUGH TODAY AND TONIGHT. WINDS WILL BE MOSTLY NORTHWEST TO NORTH TO START OUT, THEN BECOME MORE NORTHEAST TO EAST LATER TODAY INTO TONIGHT AS HIGH PRESSURE SLIDES ACROSS THE AREA TODAY, THEN INTO NEW ENGLAND TONIGHT. OVERALL, WIND SPEEDS WILL BE FAIRLY LIGHT, GENERALLY 5-8 KNOTS OR LESS. OUTLOOK... WEDNESDAY AND THURSDAY...MVFR CEILINGS ARE POSSIBLE OVER MUCH OF THE REGION AS A LOW PASSES JUST EAST OF THE REGION. THE TERMINALS EXPECTED TO HAVE THE LONGEST AND MOST SIGNIFICANT IMPACTS ARE KMIV AND KACY WHICH MAY SEE IFR CEILINGS AT TIMES. KABE AND KRDG WILL LIKELY ONLY SEE MVFR CEILINGS FOR A PORTION OF THIS PERIOD, WITH BREAKS OF VFR CONDITIONS. OCCASIONAL MVFR VISIBILITIES WITH -RA ARE ALSO POSSIBLE. FRIDAY AND SATURDAY...MOSTLY VFR CONDITIONS EXPECTED. && .MARINE...
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WINDS HAVE DROPPED BELOW ADVISORY FOR ALL AREAS, SO THE SMALL CRAFT ADVISORY HAS BEEN CANCELLED. SUB- ADVISORY CONDITIONS WILL REMAIN FOR THE REMAINDER OF TODAY INTO TONIGHT AS HIGH PRESSURE MOVES ACROSS THE AREA AND INTO NEW ENGLAND. THE PRESSURE GRADIENT WILL BEGIN TO TIGHTEN BETWEEN THE HIGH TO OUR NORTH AND A DEVELOPING AREA OF LOW PRESSURE TO OUR SOUTH OVERNIGHT TONIGHT INTO EARLY WEDNESDAY MORNING. CONDITIONS WILL BEGIN TO APPROACH ADVISORY LEVELS ONCE AGAIN BY THE PRE-DAWN HOURS WEDNESDAY. OUTLOOK... WEDNESDAY AND THURSDAY...SCA CONDITIONS (BOTH WINDS AND SEAS) ARE EXPECTED. AN SCA FOR THESE PERIODS HAS NOW BEEN ISSUED. IN ADDITION, ON THE SOUTHERN OCEAN WATERS, COULD SEE A FEW GUSTS NEAR OR AT GALE CONDITIONS, BUT CONFIDENCE IS TOO LOW TO ISSUE A GALE WATCH AT THIS TIME. FRIDAY...SEAS SLOWLY DECREASING BELOW 5 FT THROUGH THE DAY. SATURDAY...CONDITIONS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA.
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&& .TIDES/COASTAL FLOODING... INCREASING ON SHORE FLOW ASSOCIATED WITH A LOW MOVING NORTH ALONG THE COAST, COMBINED WITH HIGHER ASTRONOMICAL TIDES ASSOCIATED WITH THE NEW MOON WILL MEAN WATER LEVELS WILL APPROACH MINOR COASTAL FLOODING CRITERIA WITH THE HIGH TIDE CYCLE ON WEDNESDAY NIGHT. HOWEVER, AT THIS TIME, GUIDANCE SHOWS LEVELS STAYING JUST BELOW MINOR FLOODING, SO WILL ONLY MENTION IN THE HWO FOR NOW. && .RIP CURRENTS... AN ENHANCED RIP CURRENT RISK IS LIKELY WEDNESDAY INTO THURSDAY WITH GUSTY WINDS AND INCREASING WAVE HEIGHTS. && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM WEDNESDAY TO 6 AM EDT THURSDAY FOR ANZ430-431-450>455.
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&& $$ SYNOPSIS...JOHNSON NEAR TERM...ROBERTSON SHORT TERM...ROBERTSON LONG TERM...JOHNSON AVIATION...JOHNSON/ROBERTSON MARINE...JOHNSON/ROBERTSON TIDES/COASTAL FLOODING...JOHNSON RIP CURRENTS...JOHNSON

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