Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 251358 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 958 AM EDT WED MAR 25 2015 .SYNOPSIS... HIGH PRESSURE OFF THE MID-ATLANTIC COAST TODAY WILL MOVE AWAY FROM THE AREA. AS IT DOES, LOW PRESSURE, WILL MOVE NORTHEASTWARD FROM THE SOUTHERN PLAINS TO THE OHIO VALLEY AND BRING A WARM FRONT THROUGH THE REGION TONIGHT. A STRONG COLD FRONT, ASSOCIATED WITH THIS LOW WILL THEN MOVE ACROSS THE AREA THURSDAY NIGHT. A SECONDARY COLD FRONT SHOULD THEN PASS THROUGH THE REGION LATE FRIDAY. A LARGE AND UNSEASONABLY COOL HIGH PRESSURE SYSTEM IS EXPECTED TO BUILD DOWN FROM CANADA OVER THE WEEKEND, WITH ANOTHER COLD FRONT POSSIBLE BY MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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THE AXIS OF A MID LEVEL RIDGE WILL CROSS OVER THE REGION THIS MORNING AND THEN MOVE FARTHER OFF THE COAST THIS AFTERNOON. MEANWHILE, SURFACE HIGH PRESSURE COVERED THE NORTHEASTERN STATES EARLY THIS MORNING. THE HIGH WILL PASS OUT TO SEA TODAY LEAVING OUR REGION IN A LIGHT SURFACE FLOW FAVORING THE EAST TO SOUTH QUADRANT. HIGH CLOUDS WILL BE ON THE INCREASE FROM THE SOUTHWEST THIS MORNING, FOLLOWED BY ALTOCUMULUS AND STRATOCUMULUS FOR THIS AFTERNOON. A MID LEVEL SHORT WAVE IS FORECAST TO LIFT NORTHEASTWARD ACROSS THE GREAT LAKES TODAY. THE TAIL END OF THE FEATURE IS EXPECTED TO PASS OVER OUR REGION THIS AFTERNOON. A LINE OF SHOWERS IS SLOWING APPROACHING THE REGION THIS MORNING AND WILL START TO MOVE INTO THE DELMARVA AND EASTERN PENNSYLVANIA AROUND 11AM-NOON. THE LINE OF SHOWERS IS EXPECTED TO MOVE ACROSS THE REMAINDER OF EASTERN PENNSYLVANIA AND NEW JERSEY BETWEEN ABOUT NOON AND 300 PM. MEANWHILE, ADDITIONAL SHOWER ACTIVITY IS ANTICIPATED TO SPREAD ACROSS EASTERN PENNSYLVANIA AND NORTHERN AND CENTRAL NEW JERSEY FROM THE WEST DURING THE AFTERNOON HOURS. RAINFALL AMOUNTS SHOULD REMAIN RELATIVELY LIGHT. TOTALS ARE FORECAST TO RANGE FROM A FEW HUNDREDTHS OF AN INCH IN OUR SOUTHERN COUNTIES TO PERHAPS ONE OR TWO TENTHS OF AN INCH ACROSS THE NORTH. SOME FAIRLY DECENT WARM ADVECTION WILL TAKE PLACE ALOFT. THE 850 HPA LEVEL IS EXPECTED TO WARM FROM AROUND 0C EARLY THIS MORNING TO ABOUT 5C TO 7C BY DARK. REGARDLESS, A SHALLOW LAYER OF COLD DRY AIR IS ANTICIPATED TO LINGER BELOW 850 HPA AROUND THE ONSET OF THE PRECIPITATION. WHETHER THE DRY AIR INITIALLY EVAPORATES THE PRECIPITATION OR WHETHER IT CAUSES IT TO COOL ENOUGH TO FREEZE REMAINS IN QUESTION. AS A RESULT, THERE COULD BE A VERY BRIEF PERIOD OF SLEET AT THE START IN BERKS COUNTY, THE LEHIGH VALLEY AND THE POCONOS. TODAY`S MAXIMUM TEMPERATURES WILL BE LIMITED A BIT BY THE INCREASE IN CLOUD COVER. THEY SHOULD BE MAINLY IN THE 40S IN OUR NORTHERN AND CENTRAL COUNTIES AND IN THE LOWER 50S IN THE SOUTH.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/... MODERATE WARM ADVECTION WILL CONTINUE OVERHEAD DURING THE NIGHT AS A 40 TO 50 KNOT LOW LEVEL SOUTHWESTERLY JET DEVELOPS OVER THE COASTAL PLAIN. TEMPERATURES AT 850 HPA ARE EXPECTED TO INCREASE TO ABOUT 8C TO 10C BY DAYBREAK ON THURSDAY. A LIGHT EAST TO SOUTH SURFACE FLOW WILL CONTINUE TO BRING LOW LEVEL MOISTURE OFF THE OCEAN. AS A RESULT, WE ARE ANTICIPATING LOW CLOUDS ALONG WITH OCCASIONAL LIGHT RAIN AND DRIZZLE FOR TONIGHT. THE UPSLOPE FLOW IN THE TERRAIN OF EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY SHOULD RESULT IN AREAS OF FOG IN THOSE LOCATIONS. TEMPERATURES ARE FORECAST TO REMAIN NEARLY STEADY OR RISE SLOWLY DURING THE NIGHT. && .LONG TERM /THURSDAY THROUGH TUESDAY/... LOW PRES IN THE OH VLY AT THE START OF THE PD WILL BRING A WMFNT THRU THE REGION ON THU. THIS WILL BRING PRECIP CHCS TO THE AREA BUT ALSO MAKE FOR ONE OF THE WARMEST DAYS WE HAVE SEEN IN SOME TIME AS WE GET INTO THE WARM SECTOR ON STRONG SWLY FLOW. TEMPS WILL MAKE THE 60S WITH SOUTHERN AREAS NEARING 70, IF NOT ABOVE IT. THE LOW WILL ADVANCE EASTWARD THRU THE MRNG AND PRECIP CHCS WILL INCREASE. THERE IS ALSO A CHC OF TSTMS AS THERE IS AT LEAST SOME CAPE AND UVV AND A 50 KT LLJ TO CONTEND WITH. THE GUID IS HINTING AT A PRECIP LULL THU AFTN AS THE CDFNT APPROACHES, PERHAPS IT BECOMES MORE SHOWERY OR WE DO GET DRY SLOTTED. THEN THE PRECIP WILL PICK UP AGAIN AS THE CFP OCCURS THU EVE THRU FRI MRNG. THERE ARE SOME TIMING DIFFS WITH HOW QUICKLY THE CDFNT EXITS ON FRI. THE ECMWF IS THE FASTEST AND CLEARS EVERYTHING OUT DURG THE MRNG. THE GFS LINGERS PRECIP ACRS THE EAST THRU THE AFTN AND HAS SOME SUPPORT FROM THE NAM/WRF. THE CMC IS THE SLOWEST OF ALL MDLS. WPC GUID SUPPORTS SOMEWHAT OF THE GFS/NAM WRF SOLN SO HAVE KEPT SOME POPS THRU THE PD. LATER FRI THRU THE WEEKEND WILL SEE A LARGE AREA OF HIGH PRES BUILD DOWN FROM CANADA AND AN UNSEASONABLY DEEP H5 TROF MOVE OVER THE ERN CONUS. WITH STRONG NWLY FLOW, CAN NOT RULE OUT A FEW SHWRS, MAINLY N AND W ON SAT, BUT OTHERWISE A DRY FCST IS IN STORE THRU THE PD. TEMPS WILL BE ABOUT 10 TO 15 DEGREES BELOW NRML BOTH SAT AND SUN WITH HIGHS ONLY IN THE 40S, DESPITE THE STRONG LATE MARCH SUN. A WEAK AND FAST MOVG AREA OF LOW PRES WILL SKIRT ACRS SRN CANADA ON MON AND A WK CDFNT WILL MOVE ACRS NEW ENG AND THE NRN REACHES OF THE REGION ON MON. IT COULD TRIGGER A RAIN OR SNOW SHOWER BUT THERE IS NOT MUCH MOISTURE, SO WILL JUST CARRY LOW POPS. TUE THEN LOOKS DRY AS HIGH PRES BUILDS BACK IN. MON AND TUE SHUD SEE MODERATING TEMPS, WITH VALUES CLOSER TO NRML AS THE AFOREMENTIONED TROF MOVES EWD AND THE FLOW BECOMES LESS AMPLIFIED. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. MAINLY VFR CONDITIONS ARE ANTICIPATED UNTIL THIS EVENING. THERE WILL BE AN INCREASE IN HIGH CLOUDS THIS MORNING WITH CEILINGS EXPECTED TO LOWER INTO THE 4000 TO 6000 FOOT RANGE IN THE AFTERNOON. LIGHT RAIN SHOWERS ARE ANTICIPATED TO SPREAD ACROSS OUR TAF SITES FROM THE SOUTHWEST AND WEST BETWEEN ABOUT 1600Z AND 1800Z. THE RAIN MAY BEGIN AS A VERY BRIEF PERIOD OF SLEET AT KRDG AND KABE. A LIGHT AND VARIABLE WIND THIS MORNING IS FORECAST TO SETTLE INTO THE EAST TO SOUTH QUADRANT AROUND 4 TO 8 KNOTS FOR LATE THIS MORNING AND THIS AFTERNOON. CONDITIONS ARE EXPECTED TO LOWER THROUGH MVFR THIS EVENING AND INTO THE IFR RANGE FOR TONIGHT AS LOW LEVEL MOISTURE IS DRAWN OFF THE OCEAN BY A LIGHT EAST TO SOUTH SURFACE FLOW. OCCASIONAL LIGHT RAIN AND DRIZZLE ARE ANTICIPATED. AREAS OF FOG SHOULD DEVELOP, ESPECIALLY IN EASTERN PENNSYLVANIA AND IN NORTHERN AND CENTRAL NEW JERSEY. A LOW LEVEL SOUTHWESTERLY JET IS FORECAST TO DEVELOP OVER THE COASTAL PLAIN FOR TONIGHT. WE HAVE INCLUDED THE MENTION OF LOW LEVEL WIND SHEAR FOR KTTN, KPNE, KPHL, KILG, KMIV AND KACY. BOTH KRDG AND KABE SHOULD BE OUTSIDE THE NORTHWESTERN FRINGE OF THE SIGNIFICANT WIND ASSOCIATED WITH THE LOW LEVEL JET. AS A RESULT, WE HAVE NOT MENTIONED LOW LEVEL WIND SHEAR FOR THOSE LOCATIONS. OUTLOOK... THU MRNG...IFR CONDITIONS WITH LOW CLOUDS, FOG AND A CHANCE OF RAIN/DRIZZLE. LLWS IS PSBL THU MRNG TO MIDDAY DUE TO THE PSBL PRESENCE OF A LOW LEVEL SWLY JET OVERHEAD. MDT CONFIDENCE. THU AFTN INTO THU NIGHT...MAINLY VFR WITH OCCASIONAL MVFR AND IFR CONDITIONS IN SHOWERS AND SCATTERED THUNDERSTORMS. THERE CUD BE A LULL IN THE PRECIP THU AFTN. MDT CONFIDENCE. STRONG CFP THU NIGHT. FRI...CONDS IMPROVING TO VFR WITH NW WIND BEHIND CFP. MDT TO HIGH CONFIDENCE. SATURDAY AND SUNDAY...VFR CONDITIONS. STRONG HIGH PRESSURE. HIGH CONFIDENCE && .MARINE... HIGH PRESSURE WILL SLIDE OFF THE COAST AND OUT TO SEA TODAY. THE WIND IS EXPECTED TO SETTLE INTO THE EAST TO SOUTH QUADRANT ON THE COASTAL WATERS OF NEW JERSEY AND DELAWARE AT SPEEDS OF 10 KNOTS OR LESS. WAVE HEIGHTS SHOULD REMAIN AT 2 FEET OR LESS. A LOW LEVEL SOUTHWESTERLY JET AROUND 40 TO 50 KNOTS IS FORECAST TO DEVELOP OVERHEAD FOR TONIGHT. HOWEVER, WITH THE MILD AIR PASSING OVER THE COLD WATER THE WIND IS NOT ANTICIPATED TO MIX TO THE SURFACE DUE TO THE RESULTING ATMOSPHERIC STABILITY. A SOUTHERLY WIND IS FORECAST TO INCREASE ONLY TO ABOUT 10 TO 15 KNOTS FOR TONIGHT. WAVE HEIGHTS ON OUR OCEAN WATERS SHOULD BUILD TO 2 TO 4 FEET. OUTLOOK... THU AND FRI...SCA CONDITIONS ARE EXPECTED TO DEVELOP THU MRNG AND LAST AT LEAST INTO FRI WITH THE APPROACH AND PASSAGE OF A CDFNT. GUSTS WILL REACH INTO THE 25 TO 30 KT RANGE, WITH A WIND SHIFT FROM SOUTHWEST TO NORTHWEST OCCURRING AS THE COLD FRONT PASSES OVER THE WATERS LATE THU NIGHT. IN ADDITION, SEAS WILL STEADILY BUILD INTO THE 5 TO 8 FOOT RANGE FOR THE COASTAL WATERS DURG THU AND INTO THU NIGHT. SCA WILL BE RAISED WITH THIS PKG. SAT...THERE IS LESS CONFIDENCE ON SAT AS LINGERING SCA CONDS COULD REMAIN. IT LOOKS TO BE MARGINAL AT BEST WITH WINDS RIGHT AROUND 25 KT AND SEAS AROUND 5 FT, MAINLY ERLY. SUN...STRONG N TO NWLY FLOW AS LARGE HIGH PRES BUILD IN COULD INCREASE SEAS TO SCA AGAIN MAINLY ERLY AND WINDS CU GUST TO NR SCA CRITERIA. BOTH WIND AND SEAS SHUD SUBSIDE AS THE DAY PROGRESSES AND THE HIGH BUILDS FURTHER INTO THE REGION. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 AM THURSDAY TO 8 AM EDT FRIDAY FOR ANZ430-431-450>455. && $$ SYNOPSIS...NIERENBERG NEAR TERM...IOVINO/MEOLA SHORT TERM...IOVINO LONG TERM...NIERENBERG AVIATION...IOVINO/NIERENBERG MARINE...IOVINO/NIERENBERG

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