Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 220848 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 348 AM EST MON DEC 22 2014 .SYNOPSIS... HIGH PRESSURE CENTERED OVER EASTERN CANADA EARLY THIS MORNING WILL CONTINUE TO DRIFT EASTWARD AND IT WILL LOSE ITS INFLUENCE OVER OUR REGION GRADUALLY. WEAK LOW PRESSURE IS FORECAST TO DEVELOP OFF THE NORTH CAROLINA COAST TODAY. THE LOW IS EXPECTED TO MOVE NORTHWARD AND IT SHOULD DISSIPATE OFF THE NEW JERSEY COAST ON TUESDAY. ANOTHER AREA OF LOW PRESSURE IS ANTICIPATED TO DEVELOP OVER THE NORTHWESTERN GULF OF MEXICO ON TUESDAY AND IT IS FORECAST TO STRENGTHEN AS IT LIFTS NORTHWARD AND ACROSS THE EASTERN GREAT LAKES ON WEDNESDAY NIGHT. THE LOW IS EXPECTED TO PULL A WARM FRONT THROUGH OUR REGION ON WEDNESDAY, FOLLOWED BY A COLD FRONT EARLY ON THURSDAY. HIGH PRESSURE IS FORECAST TO BUILD INTO OUR AREA FROM THE SOUTHWEST FOR THURSDAY AND FRIDAY. ANOTHER COLD FRONT FROM THE WEST IS EXPECTED TO ARRIVE OVER THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH PRESSURE REMAINS ACROSS EASTERN CANADA AND EXTENDS SOUTHWARD ACROSS THE EAST COAST THIS MORNING, ALTHOUGH IT WILL BEGIN TO RETREAT THROUGH THE DAY AND LOSE IT`S INFLUENCE OVER THE AREA. THIS HAS ALLOWED THE STRATOCU CLOUD DECK TO REMAIN ACROSS THE AREA AND BUILD SOUTHWARD. WHERE THIS CLOUD DECK IS TEMPERATURES HAVE REMAINED WARMEST, AND WHERE SKIES WERE CLEAR OR ONLY MID/HIGH LEVEL CLOUDS TEMPERATURES HAVE COOLED OFF. AS WE GO THROUGH THE MORNING AND THROUGH MIDDAY, WE EXPECT THE LOW CLOUD DECK TO BEGIN PULLING NORTHWARD AS THE HIGH RETREATS AND A SHORT WAVE/VORT MAX LIFTS ACROSS THE AREA. HOWEVER, THESE CLOUDS WILL BE REPLACED BY ADDITIONAL CLOUDS ADVECTING INTO THE AREA FROM THE SOUTH AHEAD OF AN APPROACHING COASTAL LOW TO OUR SOUTH. LOW-MID LEVEL MOISTURE WILL INCREASE AHEAD OF THE COASTAL LOW, AND AS SEVERAL PIECES OF VORTICITY MOVE ACROSS THE AREA IN THE SOUTHWEST FLOW ALOFT, RAIN CHANCES WILL INCREASE THROUGH THE AFTERNOON. THE BEST LIFT/MOISTURE SHOULD BEGIN MOVING INTO OUR SOUTHERN AREAS DURING THE AFTERNOON, ALTHOUGH THERE COULD BE SOME SHOWERS ACROSS OUR SOUTHERN AREAS AS SOON AS LATE MORNING. WHERE THE PRECIPITATION FALLS DURING THE DAY, IT SHOULD BE ALL LIQUID RAIN AS TEMPERATURES ARE EXPECTED TO WARM ABOVE FREEZING WHERE THE PRECIPITATION CHANCES ARE MOST LIKELY. HOWEVER, THERE IS STILL A CHANCE THAT SOME SNOW AND/OR SLEET MAY MIX WITH ANY RAIN AT THE ONSET OF THE PRECIPITATION, ESPECIALLY FOR AREAS NORTH AND WEST OF THE DELAWARE VALLEY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... THE COASTAL LOW CONTINUES TO LIFT NORTHWARD THIS EVENING AND OVERNIGHT TOWARD OUR AREA. THIS WILL CONTINUE TO ALLOW LOW-MID LEVEL MOISTURE TO SPREAD ACROSS OUR AREA. ADDITIONAL PIECES OF VORTICITY WILL CONTINUE TO MOVE ACROSS THE AREA WITHIN THE SOUTHWEST FLOW ALOFT, LEADING TO ENHANCED LOW-MID LEVEL LIFT. THE BEST LIFT/MOISTURE WILL MOVE FROM SOUTH TO NORTH OVERNIGHT AND WILL LIKELY AFFECT ALL AREAS AT SOME POINT DURING THE EVENING AND OVERNIGHT. MOST AREAS WILL WARM ABOVE FREEZING BEFORE THE MAIN PRECIPITATION MOVES INTO THOSE AREA. HOWEVER, THE NORTHERN THREE COUNTIES (CARBON/MONROE, PENNSYLVANIA AND SUSSEX, NEW JERSEY) WILL LIKELY TAKE LONGER TO SCOUR OUT THE COLD AIR. THEREFORE WE EXPECT A PERIOD OF FREEZING RAIN TO OCCUR ACROSS THESE AREAS LATER THIS EVENING AND OVERNIGHT. THERE COULD BE SOME SLEET AND/OR SNOW MIX IN AT THE ONSET OF THE PRECIPITATION, BUT THE MAIN THREAT IS EXPECTED TO BE FREEZING RAIN. THEREFORE WE HAVE ISSUED A FREEZING RAIN ADVISORY FOR THESE AREAS FOR THIS EVENING AND INTO THE OVERNIGHT HOURS. ALL PRECIPITATION IS EXPECTED TO CHANGE OVER TO ALL RAIN BY DAYBREAK TUESDAY, SO THE ADVISORY WILL END AT 4 AM. && .LONG TERM /TUESDAY THROUGH SUNDAY/... THE MID LEVEL PATTERN IS EXPECTED TO FEATURE A LOW OVER IOWA WITH A TROUGH EXTENDING DOWN TO THE SOUTHERN PLAINS ON TUESDAY MORNING. MEANWHILE, A RIDGE WILL BE LOCATED OVER THE WESTERN NORTH ATLANTIC. OUR REGION IS FORECAST TO BE UNDER AN INCREASINGLY MOIST AND RELATIVELY MILD SOUTHWESTERLY FLOW FOR TUESDAY AND WEDNESDAY. THE INITIAL MID LEVEL LOW IS ANTICIPATED TO LIFT OVER CENTRAL ONTARIO ON TUESDAY NIGHT WITH ANOTHER LOW DEVELOPING OVER EASTERN OKLAHOMA AND VICINITY AT THAT TIME. THE SECOND MID LEVEL LOW SHOULD REACH SOUTHEASTERN ONTARIO LATE ON WEDNESDAY NIGHT AND QUEBEC ON THURSDAY, WHEN IT SHOULD PULL ITS TROUGH AXIS OVER OUR REGION. OUR WEATHER IS EXPECTED TO BE RATHER UNSETTLED THROUGH THAT TIME, WITH PERIODS OF RAIN FROM TUESDAY INTO WEDNESDAY NIGHT, TAPERING TO RAIN SHOWERS ON THURSDAY MORNING BEFORE ENDING. FORECAST TEMPERATURE PROFILES FOR THAT PERIOD SUGGEST ALL LIQUID PRECIPITATION. A LIGHT SURFACE FLOW FROM THE EAST TO SOUTH QUADRANT IS FORECAST FOR TUESDAY AND TUESDAY NIGHT. THE WIND IS EXPECTED TO SETTLE INTO THE SOUTH ON WEDNESDAY AS A WARM FRONT LIFTS THROUGH OUR REGION. TEMPERATURES ARE ANTICIPATED TO BECOME QUITE MILD ON WEDNESDAY WITH MAXIMUM READINGS IN THE 50S AND 60S. AS OUR MID WEEK WEATHER SYSTEM EVOLVES, IT WILL HAVE AMPLE OPPORTUNITY TO TAP INTO MOISTURE FROM THE GULF OF MEXICO WHICH IT WILL DRAW IN OUR DIRECTION. A LOW LEVEL JET AROUND 45 TO 55 KNOTS IS EXPECTED TO DEVELOP OVER THE COASTAL PLAIN. THE STRONGEST OF THE WINDS SHOULD HAVE A DIFFICULT TIME MIXING TO THE SURFACE. HOWEVER, SOME GUSTS AROUND 30 OR 35 MPH SEEM POSSIBLE. THE SYSTEM IS ANTICIPATED TO PULL A COLD FRONT THROUGH OUR REGION EARLY ON CHRISTMAS MORNING SIGNALING THE BEGINNING OF THE END OF THE RAIN EVENT AS WELL AS A RETURN TO NEAR SEASONABLE TEMPERATURES FOR THE BALANCE OF THE WEEK AND INTO THE WEEKEND. THE MODELS HAVE BEEN TRENDING TOWARD LOWER RAINFALL AMOUNTS FOR THE MID WEEK EVENT THAN THEY HAD BEEN SHOWING OVER PREVIOUS DAYS. THE GENERAL CONSENSUS SUGGESTS RAINFALL TOTALS MAINLY IN THE 0.75 TO 1.25 INCH RANGE FOR OUR REGION. WE SHOULD BE ABLE TO HANDLE THOSE AMOUNTS BASED ON ANTECEDENT CONDITIONS WITH NOT MUCH MORE THAN SOME LOCALIZED FLOODING IN AREAS OF POOR DRAINAGE. THE MODEL GUIDANCE CONTINUES TO DIFFER ON THE HANDLING OF THE MID LEVEL SHORT WAVE AND THE ACCOMPANYING COLD FRONT FOR THE COMING WEEKEND. WE WILL KEEP THE MENTION OF A SLIGHT CHANCE OF SNOW SHOWERS AND RAIN SHOWERS FOR THE TIME BEING WITH THE HOPE THAT THE MODELS WILL COME INTO BETTER AGREEMENT DURING THEIR SUBSEQUENT RUNS. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. MVFR CIGS REMAIN ACROSS THE NORTHERN HALF OF THE AREA AS THE STRATO CUMULUS CLOUD DECK REMAINS ACROSS THE AREA. THIS DECK MAY SAG DOWN ACROSS PHL AND RDG THIS MORNING. WE EXPECT THIS CLOUD DECK TO RETREAT NORTHWARD DURING THE DAY, WITH A BRIEF PERIOD OF VFR CONDITIONS POSSIBLE. HOWEVER, THIS WILL BE TEMPORARY AS ADDITIONAL MVFR CIGS SHOULD RETURN TO THE TAF SITES BY THE LATE AFTERNOON/EVENING HOURS AS RAINFALL MOVES INTO THE AREA. AS WE MOVE INTO THE EVENING AND OVERNIGHT HOURS, WE EXPECT CIGS TO LOWER TO IFR WITH LIGHT RAIN OR DRIZZLE CONTINUING INTO THE OVERNIGHT HOURS. WINDS ARE MOSTLY LIGHT AND VARIABLE/CALM THIS MORNING, ALTHOUGH ANY WIND DIRECTION IS FROM THE NORTHWEST-NORTH. WINDS WILL INCREASE TO AROUND 5 KNOTS OUT OF THE NORTHEAST-EAST DURING THE DAY AND CONTINUE INTO THIS EVENING AND OVERNIGHT. OUTLOOK... 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. THURSDAY NIGHT AND FRIDAY...MAINLY VFR. && .MARINE... CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS TODAY AS HIGH PRESSURE TO OUR NORTH BEGINS TO RETREAT. AS A COASTAL LOW APPROACHES THE AREA THIS EVENING AND OVERNIGHT, WINDS MAY BEGIN TO INCREASE AND COULD GUST TO AROUND 20 KNOTS. SEAS AROUND 1-2 FEET THIS MORNING WILL INCREASE LATER TODAY AND ESPECIALLY OVERNIGHT AS THE COASTAL LOW APPROACHES AND SEAS MAY BEGIN TO APPROACH 4 FEET. OUTLOOK... TUESDAY AND TUESDAY NIGHT...WAVE HEIGHTS ON OUR OCEAN WATERS MAY BUILD TO 5 FEET IN A DEVELOPING EAST TO SOUTH 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 6 TO 9 FEET. THURSDAY...WESTERLY WIND GUSTS IN EXCESS OF 25 KNOTS ARE EXPECTED. LOCALIZED GALE FORCE GUSTS ARE POSSIBLE. WAVE HEIGHTS ON OUR OCEAN WATERS MAY BE TO 5 TO 7 FEET. THURSDAY NIGHT...WIND GUSTS AND WAVE HEIGHTS ARE FORECAST TO FALL GRADUALLY BELOW THE SMALL CRAFT ADVISORY CRITERIA. FRIDAY...NO MARINE HEADLINES ARE ANTICIPATED. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 4 AM EST TUESDAY FOR PAZ054-055. NJ...FREEZING RAIN ADVISORY FROM 6 PM THIS EVENING TO 4 AM EST TUESDAY FOR NJZ001. DE...NONE. MD...NONE. MARINE...NONE. && $$ SYNOPSIS...IOVINO NEAR TERM...ROBERTSON SHORT TERM...ROBERTSON LONG TERM...IOVINO AVIATION...IOVINO/ROBERTSON MARINE...IOVINO/ROBERTSON

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