Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 241342 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 942 AM EDT TUE MAR 24 2015 .SYNOPSIS... HIGH PRESSURE IS CENTERED NEAR THE GREAT LAKES REGION TODAY, HOWEVER IT EXTENDS DOWN INTO THE MID ATLANTIC. THE HIGH IS FORECAST TO SLIDE OFF THE NEW ENGLAND AND MID ATLANTIC COASTS EARLY ON WEDNESDAY. A WARM FRONT WILL LIFT THROUGH OUR REGION WEDNESDAY NIGHT AND THURSDAY MORNING, THEN A STRONG COLD FRONT ARRIVES THURSDAY EVENING. A SECONDARY COLD FRONT SHOULD MOVE THROUGH OUR AREA LATE FRIDAY, THEN HIGH PRESSURE FOLLOWS FOR THE WEEKEND WITH ANOTHER COLD FRONT ANTICIPATED FOR MONDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A SHORT WAVE IS EXITING TO OUR EAST THIS MORNING. THIS FEATURE DID GENERATE PRECIPITATION ALOFT FOR THE SOUTHERN AREAS, HOWEVER WEAKENING LIFT AND RATHER DRY LOW-LEVEL AIR RESULTED IN LITTLE TO NO FLURRIES REACHING THE GROUND. WE ARE LEFT WITH THE CLOUD DECK UNDER A SUBSIDENCE INVERSION, HOWEVER DRYING HAS ERODED THIS ACROSS THE NORTHERN AREAS. THIS IS TRYING TO SETTLE SOUTHWARD HOWEVER CLOUDS ALL THE WAY BACK ACROSS THE SOUTHERN HALF OF PENNSYLVANIA ARE MOVING EASTWARD. THEREFORE, IT WILL TAKE SOME TIME FOR INCREASING SUNSHINE FARTHER SOUTH. A SECONDARY AND STRONGER SHORT WAVE FROM THE EASTERN GREAT LAKES WILL MOVE THROUGH DURING ABOUT THE MIDDAY HOURS. THIS IS ASSOCIATED WITH AN UPPER-LEVEL TROUGH AXIS. THERE APPEARS TO BE LITTLE MOISTURE WITH THIS FEATURE OTHER THAN SOME CLOUDS. AS THIS FEATURE MOVES THROUGH AND THE ASSOCIATED VORTICITY BECOMES MORE CHANNELIZED, WE SHOULD SEE MORE OF AN EROSION OF THE CLOUD COVER FROM NORTH TO SOUTH DURING THE COURSE OF THE AFTERNOON. THE HOURLY GRIDS WERE ADJUSTED TO SHOW A SLOWER RISE IN THE TEMPERATURES FOR AWHILE THIS MORNING. THIS IS DUE TO LESS MIXING AND CLOUD COVER ACROSS MUCH OF THE CWA. THE LOW-LEVEL FLOW IS MORE NORTHEASTERLY AS WELL, HOWEVER SOME TURN TO THE NORTH-NORTHWEST SHOULD TAKE PLACE FOR SOME AREAS THIS AFTERNOON ALTHOUGH THE WIND SPEEDS ARE EXPECTED TO BE ON THE LIGHTER SIDE OVERALL. NO MAJOR CHANGES WERE MADE TO THE HIGH TEMPERATURES ATTM. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/... THE HIGH WILL BEGIN TO MOVE OFF THE COAST TONIGHT THE FLOW WILL BECOME VERY LIGHT AND COULD EVEN GO CALM. LOW PRES NR THE GRTLKS WILL HAVE A WMFNT APPROACHING THE REGION FROM THE SW BY DAYBREAK. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... A MID LEVEL RIDGE AXIS IS FORECAST TO BE OVERHEAD ON WEDNESDAY MORNING. THE RIDGE IS EXPECTED TO MOVE EASTWARD. A SHORT WAVE TROUGH IS ANTICIPATED TO LIFT NORTHEASTWARD IN THE MID LEVEL FLOW ON THE BACK SIDE OF THE RIDGE WITH MOST OF ITS ENERGY REMAINING OVER THE GREAT LAKES. NEVERTHELESS, WE ARE FORECASTING LIGHT RAIN TO DEVELOP ON WEDNESDAY IN THE WARM ADVECTION WITH GREATER CHANCE FOR RAIN BEING ACROSS EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY WITH LESSER CHANCES TO THE SOUTHEAST. IT APPEARS AS THOUGH ENOUGH WARMING WILL TAKE PLACE TO ALLOW FOR A MAINLY LIQUID EVENT. HOWEVER, THERE COULD BE ENOUGH LOW LEVEL DRY AIR AT THE START TO RESULT IN EVAPORATIVE COOLING AND A BIT OF SLEET AT THE ONSET IN PARTS OF EASTERN PENNSYLVANIA AND NORTHERN NEW JERSEY. WARM AIR WILL CONTINUE TO BUILD OVER AND INTO OUR REGION FROM THE SOUTHWEST ON WEDNESDAY NIGHT AND THURSDAY MORNING AS SURFACE HIGH PRESSURE MOVES FARTHER OFF THE COAST AND AS A STRONG COLD FRONT APPROACHES FROM THE NORTHWEST. WE ARE FORECASTING A CHANCE OF RAIN AND DRIZZLE DURING THAT PERIOD ALONG WITH LOW CLOUDS AND FOG. A MODERATE SOUTHWEST SURFACE FLOW IS EXPECTED TO DEVELOP ON THURSDAY AND IT SHOULD RESULT IN BREEZY CONDITIONS ALONG WITH MILD TEMPERATURES. HIGHS ARE FORECAST TO BE IN THE 60S IN MUCH OF OUR REGION AND PERHAPS INTO THE LOWER 70S IN THE SOUTH. THE INCREASINGLY MOIST AND MILD AIR WILL RESULT IN BUILDING ATMOSPHERIC INSTABILITY IN OUR REGION ON THURSDAY AFTERNOON AND THURSDAY EVENING. MIXED LAYER CAPE VALUES ARE FORECAST TO PEAK AROUND 400 J/KG DURING THAT TIME. THE STRONG COLD FRONT IS EXPECTED TO MOVE ACROSS OUR REGION EARLY ON THURSDAY NIGHT. WE ARE FORECASTING SHOWERS AND THUNDERSTORMS FOR THURSDAY AFTERNOON INTO THURSDAY EVENING WITH THE POTENTIAL FOR BRIEF DOWNPOURS AND ISOLATED STRONG WIND GUSTS. PRECIPITATION TOTALS SHOULD FAVOR THE 0.25 TO 0.75 INCH RANGE BASED ON THE CONSENSUS OF THE LATEST GUIDANCE. THE CHANCE FOR RAIN IS ANTICIPATED TO DECREASE LATE ON THURSDAY NIGHT. ANY LOW AND MID LEVEL CLOUDS AND LINGERING SHOWERS SHOULD MOVE TO OUR EAST ON FRIDAY MORNING WITH PERHAPS SOME CIRRUS REMAINING IN ASSOCIATION WITH AN UPPER LEVEL JET. A SECONDARY COLD FRONT IS FORECAST TO ARRIVE ON FRIDAY NIGHT. IT MAY BRING SOME STRATOCUMULUS AND ALTOCUMULUS TO OUR REGION ALONG WITH A SLIGHT CHANCE OF SNOW AND RAIN SHOWERS IN THE NORTH. THE AXIS OF THE LONG WAVE TROUGH IS ANTICIPATED TO PASS OVERHEAD ON SATURDAY. SURFACE HIGH PRESSURE IS FORECAST TO BUILD ACROSS OUR REGION OVER THE WEEKEND WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES. HIGH CLOUDS MAY START TO OVERSPREAD OUR REGION ON SUNDAY AS OUR NEXT WEATHER SYSTEM BEGINS TO APPROACH FROM THE NORTHWEST. MID LEVEL CLOUDS ARE ANTICIPATED TO ARRIVE FOR SUNDAY NIGHT INTO MONDAY ALONG WITH A LOW CHANCE OF RAIN AND SNOW SHOWERS MAINLY IN THE NORTH. A COLD FRONT IS FORECAST TO ARRIVE ON MONDAY WITH A MID LEVEL SHORT WAVE TROUGH AXIS EXPECTED TO PASS OVERHEAD LATE IN THE DAY. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. REST OF TODAY...VFR CEILINGS SCATTERING OUT FROM NORTH TO SOUTH THROUGH THE AFTERNOON. NORTHEASTERLY WINDS MAINLY LESS THAN 10 KNOTS, SHOULD TURN MORE NORTH-NORTHWEST THIS AFTERNOON. THERE IS THE POTENTIAL THAT THE WINDS BECOME LOCALLY SOUTHERLY OR LIGHT/VARIABLE TOWARD EVENING. TONIGHT...VFR WITH LITTLE TO NO CLOUDS. LIGHT AND VARIABLE TO LOCALLY CALM WINDS. WEDNESDAY...VFR WITH INCREASING CLOUDS. THE CEILING MAY LOWER TO MVFR IN THE AFTERNOON ESPECIALLY IN THE KRDG AND KABE AREAS. SOME SHOWERS SHOULD DEVELOP IN THE AFTERNOON MOSTLY WEST OF KPHL. THERE COULD BE A BRIEF PERIOD OF SLEET AT THE ONSET AROUND KRDG, KABE AND KTTN. SOUTHEASTERLY WINDS GENERALLY 5-10 KNOTS. OUTLOOK... WEDNESDAY NIGHT INTO THURSDAY MORNING...WIDESPREAD IFR CONDITIONS WITH LOW CLOUDS, FOG AND A CHANCE OF RAIN AND DRIZZLE. LOW LEVEL WIND SHEAR IS POSSIBLE ON THURSDAY MORNING DUE TO THE POSSIBLE PRESENCE OF A LOW LEVEL SOUTHWESTERLY JET OVERHEAD. THURSDAY AFTERNOON INTO THURSDAY NIGHT...MAINLY VFR WITH OCCASIONAL MVFR AND IFR CONDITIONS IN SHOWERS AND SCATTERED THUNDERSTORMS. FRIDAY THROUGH SATURDAY...MAINLY VFR. && .MARINE... A QUIET PD IS IN STORE ON THE COASTAL WATERS WITH HIGH PRES TO THE N TODAY AND THEN BEGINNING TO MOVE OFFSHORE TONIGHT. LIGHT NLY FLOW IS EXPECTED TODAY AND LIGHT ELY FLOW TONIGHT. BOTH WIND AND SEAS ARE EXPECTED TO REMAIN BELOW SCA CRITERIA THRU THE NR AND SHORT TERM PDS. OUTLOOK... WEDNESDAY AND WEDNESDAY NIGHT...NO MARINE HEADLINES ARE ANTICIPATED. THURSDAY AND THURSDAY EVENING...A SMALL CRAFT ADVISORY MAY BE NEEDED DUE TO A GUSTY SOUTHWEST WIND AND BUILDING SEAS. WAVE HEIGHTS ON OUR OCEAN WATER MAY BUILD TO 6 OR 7 FEET. THE MILD AIR PASSING OVER THE COLD WATER SHOULD KEEP GALE FORCE WIND GUSTS FROM REACHING THE WATER`S SURFACE EVEN WITH A STRONG LOW LEVEL SOUTHWESTERLY JET EXPECTED TO BE OVERHEAD ON THURSDAY. LATE THURSDAY NIGHT INTO FRIDAY MORNING...WAVE HEIGHTS ON OUR OCEAN WATERS MAY REMAIN AROUND 5 FEET. FRIDAY AFTERNOON THROUGH SATURDAY...NO MARINE HEADLINES ARE ANTICIPATED. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...GORSE/IOVINO NEAR TERM...GORSE SHORT TERM...NIERENBERG LONG TERM...IOVINO AVIATION...GORSE/IOVINO MARINE...IOVINO/NIERENBERG

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