Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 211432 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 932 AM EST SUN DEC 21 2014 .SYNOPSIS... HIGH PRESSURE CENTERED OVER QUEBEC EARLY THIS MORNING WILL DRIFT EASTWARD AND IT SHOULD REACH ATLANTIC CANADA ON MONDAY. WEAK LOW PRESSURE IS FORECAST TO DEVELOP OFF THE CAROLINA COAST ON MONDAY BEFORE MOVING SLOWLY NORTHEASTWARD AND DISSIPATING OFF THE DELMARVA PENINSULA ON TUESDAY. LOW PRESSURE IS EXPECTED TO DEVELOP AROUND THE CENTRAL GULF COAST REGION ON TUESDAY. THE LOW SHOULD STRENGTHEN AS IT LIFTS NORTHWARD AND ACROSS THE EASTERN GREAT LAKES ON WEDNESDAY NIGHT. THE LOW IS ANTICIPATED TO PULL A WARM FRONT THROUGH OUR REGION ON WEDNESDAY, FOLLOWED BY A COLD FRONT LATE ON WEDNESDAY NIGHT. HIGH PRESSURE IS EXPECTED TO FOLLOW FROM THE SOUTHWEST FOR THURSDAY AND FRIDAY. ANOTHER COLD FRONT FROM THE WEST IS FORECAST TO ARRIVE ON SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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THE CENTER OF A 1030 MB SURFACE HIGH WAS ANALYZED OVER EASTERN CANADA AT 14Z THIS MORNING. THIS BROAD AREA OF HIGH PRESSURE ENCOMPASSES MOST OF THE EASTERN SEABOARD. THE PRESSURE GRADIENT AND RESULTANT WINDS WILL BE LIGHT OVER THE MID-ATLANTIC REGION TODAY UNDER THIS SETUP. STRATOCU STILL HOLDING STRONG OVER NORTHEAST PA AND NORTHERN NJ THIS MORNING, WHERE HIGHER MOISTURE IN ASSOCIATION WITH A PASSING SHORTWAVE TROUGH TO OUR NORTHEAST REMAINS TRAPPED BELOW THE SUBSIDENCE INVERSION AT AROUND 900 MB. THE DELMARVA IS POSITIONED IN THE RIGHT ENTRANCE REGION OF MID-LEVEL JET STREAK, RESULTING IN OVERCAST MID CLOUDS IN OUR SOUTHERN ZONES. HOWEVER, THERE IS A BAND OF CLEARING EVIDENT ON THE LATEST VISIBLE SATELLITE IMAGERY IN THE MIDDLE PART OF THE CWA THAT IS DEVELOPING OVER SOUTHEAST PA, INCLUDING PHILLY AND ADJACENT CENTRAL/SOUTHERN NJ MID MORNING. THE CLEARING SHOULD EXPAND SOUTH AND EASTWARD THRUOUT THE DAY AS THE JET STREAK PROGRESSES OFF THE COAST, ALTHOUGH THE HEATING WILL LEAD TO DEVELOPMENT OF SCATTERED STRATOCU. CLOUDS SHOULD BE SLOWER TO ERODE OVER NORTHEAST PA AND NORTHWEST NJ THRU MIDDAY, BUT SOME SUN IS ANTICIPATED LATER IN THE AFTERNOON. ONLY MADE MINOR ADJUSTMENTS TO THE MAX TEMP FORECAST BASED OFF CHANGES MADE TO THE SKY GRIDS. MAX TEMPS RANGE FROM THE LOWER 30S IN THE POCONOS TO AROUND 40F IN PHILLY, SOUTHERN NJ AND THE DELMARVA.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/... THE HIGH PRESSURE BEGINS TO RETREAT SOME OVERNIGHT TONIGHT, BUT OUR AREA WILL STILL REMAIN ON THE SOUTHERN FRINGE. ANY PARTIAL CLEARING THAT OCCURRED DURING THE DAY WILL CONTINUE INTO THE EVENING, BUT HIGH LEVEL CLOUD COVER MAY BEGIN TO DEVELOP AND SPREAD BACK INTO THE AREA OVERNIGHT AS A WEAK SHORT WAVE LIFTS THROUGH THE AREA. WE ARE NOT EXPECTING ANY PRECIPITATION OVERNIGHT AS THERE IS A LACK OF SIGNIFICANT VERTICAL MOISTURE. LOW TEMPERATURES ARE A BLEND OF MAV/MET MOS AND MOSGUIDE WHICH WERE ALL IN PRETTY GOOD AGREEMENT. && .LONG TERM /MONDAY THROUGH SATURDAY/... A MID LEVEL RIDGE AXIS SHOULD BE TO OUR EAST ON MONDAY. AN IMPULSE TRAVELING IN THE MID LEVEL FLOW IS EXPECTED TO PASS OVERHEAD ON MONDAY AFTERNOON. MOISTURE IS FORECAST TO SPREAD INTO OUR REGION FROM THE SOUTH AT THAT TIME. WE HAVE MENTIONED A CHANCE OF RAIN ARRIVING FROM SOUTH TO NORTH FROM THE LATE MORNING INTO THE AFTERNOON HOURS. THE FORECAST TEMPERATURE PROFILES SUGGEST THAT THE BOUNDARY LAYER WILL BE ABLE TO SUPPORT ALL RAIN EVEN UP NORTH WHERE THE CHANCE FOR PRECIPITATION IS THE LOWEST IN OUR REGION. SURFACE HIGH PRESSURE IS FORECAST TO BE LOCATED OVER ATLANTIC CANADA FROM MONDAY INTO TUESDAY. A RIDGE AXIS IS EXPECTED TO NOSE SOUTHWESTWARD ALONG THE LEE OF THE APPALACHIANS AT THAT TIME WITH AN INVERTED TROUGH DEVELOPING OFF THE COAST. WEAK LOW PRESSURE IS ANTICIPATED TO DEVELOP ON THE TROUGH OFF THE CAROLINA COAST ON MONDAY. THE FEATURE IS FORECAST TO REMAIN WEAK AS IT DRIFTS NORTHEASTWARD REACHING THE WATERS OFF THE DELMARVA PENINSULA BEFORE DISSIPATING ON TUESDAY. MEANWHILE, A DEEP MID LEVEL TROUGH IS EXPECTED TO DIG OVER THE MIDDLE PART OF THE COUNTRY ON MONDAY AND TUESDAY AS THE RIDGE OVER THE WESTERN NORTH ATLANTIC BECOMES MORE PRONOUNCED. THE PATTERN WILL RESULT IN THE DEVELOPMENT OF STRONG WARM ADVECTION OVER OUR REGION FROM TUESDAY INTO TUESDAY NIGHT. THE PATTERN SHOULD KEEP OUR REGION OVERCAST WITH A CHANCE OF RAIN FROM MONDAY NIGHT INTO TUESDAY WITH THE PROBABILITY OF PRECIPITATION INCREASING TO LIKELY FOR TUESDAY NIGHT. IT CONTINUES TO APPEAR AS THOUGH THERE MAY BE POCKETS OF BELOW FREEZING TEMPERATURES IN THE POCONOS AND IN FAR NORTHERN NEW JERSEY FROM MONDAY NIGHT INTO TUESDAY MORNING TO POSSIBLY RESULT IN SOME LOCALIZED LIGHT FREEZING RAIN. SURFACE LOW PRESSURE IS ANTICIPATED TO DEVELOP AROUND THE CENTRAL GULF COAST REGION ON TUESDAY IN RESPONSE TO THE DEEP MID LEVEL TROUGH. THE LOW IS FORECAST TO STRENGTHEN AS IT MOVES NORTHWARD ON WEDNESDAY AND ACROSS THE EASTERN GREAT LAKES ON WEDNESDAY NIGHT. THE SYSTEM SHOULD HAVE AN OPPORTUNITY TO TAP INTO GULF MOISTURE AND IT WILL BRING THE POTENTIAL FOR SOME MODERATE TO HEAVY RAINFALL TO OUR REGION FROM LATE TUESDAY NIGHT INTO EARLY WEDNESDAY NIGHT. THE CONSENSUS OF THE MODELS CONTINUES TO SUGGEST REPRESENTATIVE RAINFALL AMOUNTS UP TO AN INCH TO AN INCH AND A HALF IN OUR REGION DURING THE MID WEEK PERIOD. THE LOW IS EXPECTED TO PULL A WARM FRONT THROUGH OUR REGION ON WEDNESDAY WITH TEMPERATURES FORECAST TO RISE INTO THE 50S AND LOWER 60S. A STRONG COLD FRONT IS FORECAST TO FOLLOW LATE ON WEDNESDAY NIGHT WITH TEMPERATURES DROPPING BACK INTO THE UPPER 30S AND LOWER 40S BY DAYBREAK ON THURSDAY. THE PROBABILITY OF PRECIPITATION DECREASES RAPIDLY LATE ON WEDNESDAY NIGHT AS DRY AIR IS EXPECTED TO BEGIN BUILDING INTO OUR REGION FROM THE WEST AND SOUTHWEST. CONDITIONS ARE ANTICIPATED TO BECOME QUITE BREEZY IN THE WAKE OF THE COLD FRONT FOR CHRISTMAS DAY. A WEST WIND AROUND 15 TO 20 MPH IS FORECAST WITH GUSTS NEAR 30 MPH. TEMPERATURES SHOULD RETURN TO SEASONABLE LEVELS FOR THURSDAY, FRIDAY AND SATURDAY. RIDGING IS FORECAST TO DEVELOP AT THE SURFACE AND ALOFT FOR THURSDAY NIGHT INTO FRIDAY WITH DRY WEATHER ANTICIPATED. A MID LEVEL SHORT WAVE IS EXPECTED TO APPROACH FROM THE WEST ALONG WITH AN ASSOCIATED SURFACE COLD FRONT. THE FRONT IS FORECAST TO PASS THROUGH OUR REGION ON SATURDAY. THE SYSTEM IS FORECAST TO BE FAST MOVING AND IT SHOULD NOT HAVE MUCH OF AN OPPORTUNITY TO TAP INTO A MOISTURE SOURCE. AS A RESULT, WE WILL NOT FORECAST ANY PRECIPITATION WITH THE FRONT AT THIS TIME. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR TODAY. CLEARING HAS ALREADY OCCURRED ACROSS PHILLY AREA TERMINALS THIS MORNING WHILE ABE REMAINS OVC JUST ABOVE 3000 FT. EXPECT SCT CIGS AROUND 3 KFT THIS AFTN FOR ALL TERMINALS. WINDS WILL BE LIGHT (BELOW 10 KT). WINDS WILL BECOME LIGHT AND VARIABLE/CALM ONCE AGAIN TONIGHT. OUTLOOK... MONDAY...MAINLY VFR WITH A CHANCE OF LIGHT RAIN SPREADING NORTHWARD INTO OUR REGION. MONDAY NIGHT AND TUESDAY...CONDITIONS POSSIBLY LOWERING INTO THE MVFR CATEGORY WITH A CHANCE OF LIGHT RAIN. TUESDAY NIGHT...MVFR AND IFR CONDITIONS ANTICIPATED WITH RAIN LIKELY. WEDNESDAY AND WEDNESDAY NIGHT...MVFR AND IFR CONDITIONS WITH RAIN LIKELY. THE RAIN MAY BE HEAVY AT TIMES. THURSDAY...CONDITIONS IMPROVING TO VFR WITH A GUSTY WEST WIND.
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&& .MARINE... SUB-SMALL CRAFT ADVISORY CONDITIONS WILL REMAIN TODAY INTO TONIGHT AS HIGH PRESSURE FROM THE NORTH WILL CONTINUE TO AFFECT THE WATERS. OUTLOOK... MONDAY AND MONDAY NIGHT...NO MARINE HEADLINES ARE ANTICIPATED. TUESDAY AND TUESDAY NIGHT...WAVE HEIGHTS ON OUR OCEAN WATERS MAY BUILD TO 5 FEET IN A DEVELOPING ONSHORE FLOW. WEDNESDAY...SOUTHERLY WIND GUSTS IN EXCESS OF 25 KNOTS ARE EXPECTED. WAVE HEIGHTS ON OUR OCEAN WATERS MAY BUILD TO 6 TO 9 FEET. WEDNESDAY NIGHT...A SOUTH WIND BECOMING WEST. WIND GUSTS IN EXCESS OF 25 KNOTS ARE EXPECTED. WAVE HEIGHTS ON OUR OCEAN WATERS MAY BE TO 6 TO 9 FEET. THURSDAY...WESTERLY WIND GUSTS IN EXCESS OF 25 KNOTS ARE EXPECTED. WAVE HEIGHTS ON OUR OCEAN WATERS MAY BE TO 5 TO 7 FEET. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...IOVINO NEAR TERM...KLEIN SHORT TERM...ROBERTSON LONG TERM...IOVINO AVIATION...IOVINO/KLEIN/ROBERTSON MARINE...IOVINO/ROBERTSON

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