Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 021323 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 823 AM EST MON MAR 2 2015 .SYNOPSIS... A COLD FRONT WAS MAKING ITS WAY THROUGH OUR REGION EARLY THIS MORNING. HIGH PRESSURE CENTERED OVER IOWA WILL BUILD TO THE EAST AND IT IS FORECAST TO PASS OFF THE MIDDLE ATLANTIC COAST ON TUESDAY. A WARM FRONT IS EXPECTED TO LIFT THROUGH OUR AREA ON TUESDAY EVENING. A COLD FRONT FROM THE NORTHWEST IS ANTICIPATED TO ARRIVE ON WEDNESDAY AFTERNOON. THE BOUNDARY SHOULD SINK SLOWLY TO THE SOUTHEAST ON WEDNESDAY NIGHT AND THURSDAY AS LOW PRESSURE RIDES ALONG IT. ANOTHER ARCTIC HIGH IS FORECAST TO BUILD ACROSS OUR REGION FROM THE WEST FOR FRIDAY INTO SATURDAY. A WARM FRONT MAY BEGIN TO APPROACH FROM THE SOUTHWEST ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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820 AM UPDATE... WINTER WX ADVISORY FOR THE DELMARVA AND SOUTHEASTERN NJ WERE CANCELLED WITH PRECIP FINALLY OFFSHORE. THERE WILL STILL BE SOME ICY SPOTS OVER THE NEXT COUPLE OF HOURS ON UNTREATED SURFACES. SCT SNOW SHOWERS AND FLURRIES WERE ALSO ADDED TO THE MORNING FORECAST FOR NORTHEASTERN PA AND NORTHERN NJ. PREVIOUS DISCUSSION... A COLD FRONT WILL APPROACH THE AREA FROM THE WEST EARLY THIS MORNING, AND PROGRESS ACROSS AND OFFSHORE AROUND OR SHORTLY AFTER SUNRISE. GUIDANCE CONTINUES TO INDICATE SOME LIGHT PRECIPITATION DEVELOPING ACROSS SOUTHERN NEW JERSEY AND THE SOUTHERN PORTIONS OF THE DELMARVA THROUGH AROUND SUNRISE AS THE FRONT APPROACHES AND A SHORT WAVE ALOFT HELPS CREATE SOME SHOWERS. ALSO, SOME PATCHY FOG/DRIZZLE WILL CONTINUE FOR A FEW MORE HOURS THIS MORNING UNTIL THE COLD FRONT MOVES THROUGH THE AREA. WE HAVE CANCELLED THE ADVISORY FOR EVERYONE EXCEPT FOR THE AREAS ACROSS SOUTHERN NEW JERSEY AND THE SOUTHERN PORTIONS OF THE DELMARVA WHERE THERE REMAINS THE THREAT FOR SOME FREEZING RAIN/SLEET THIS MORNING. TEMPERATURES ARE AT OR BELOW FREEZING FOR MOST AREAS THIS MORNING. TEMPERATURES WILL RISE THROUGH THE DAY WITH SUNSHINE RETURNING, BUT WILL REMAIN BELOW NORMAL EVERYWHERE. ONCE THE FRONT MOVES THROUGH THE AREA, ALL PRECIPITATION WILL END AND SKIES WILL BEGIN TO PARTIALLY CLEAR BEHIND IT. ALSO, WEST- NORTHWEST WINDS WILL BECOME QUITE GUSTY BEHIND THE FRONT, GUSTING AROUND 25-30 MPH AT TIMES THROUGH THE DAY.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... HIGH PRESSURE BEGINS TO MOVE INTO THE AREA THIS EVENING, BEFORE CENTERING ITSELF ACROSS THE AREA OVERNIGHT. SKIES WILL CLEAR OUT THIS EVENING, ALTHOUGH SOME HIGH LEVEL CLOUD COVER MAY RETURN OVERNIGHT. WIND GUSTS WILL HAVE DROPPED OFF BY THE EVENING, ALTHOUGH A STEADY BREEZE WILL REMAIN THROUGH THE EVENING, BEFORE BECOMING LIGHT AND VARIABLE OVERNIGHT. WITH MOSTLY CLEAR SKIES AND LIGHT WINDS, TEMPERATURES SHOULD BE ABLE TO DROP WELL BELOW NORMAL OVERNIGHT. && .LONG TERM /TUESDAY THROUGH SUNDAY/... THERE IS NOT MUCH CHANGE REGARDING THE FORECAST FOR TUESDAY INTO WEDNESDAY. PRECIPITATION IS EXPECTED TO OVERSPREAD OUR REGION QUICKLY FROM THE WEST ON TUESDAY AFTERNOON. THE FORECAST TEMPERATURE PROFILES SUGGEST THAT THE PRECIPITATION WILL BEGIN AS SNOW IN MOST LOCATIONS WITH PERHAPS SLEET AT THE START IN OUR FAR SOUTHERN COUNTIES. STRONG WARM ADVECTION IS ANTICIPATED ALOFT FROM TUESDAY AFTERNOON INTO TUESDAY EVENING. WARMING AT THE SURFACE WILL LAG A BIT. THERE SHOULD BE A GRADUAL TRANSITION FROM A WINTRY MIX TO RAIN FROM SOUTH TO NORTH. HOWEVER, TRAPPED COLD AIR IN OUR FAR NORTHERN COUNTIES COULD RESULT IN SEVERAL HOURS OF FREEZING RAIN THERE ON TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING. OUR LATEST PROJECTIONS FOR TUESDAY INTO TUESDAY NIGHT BRING 1 TO 3 INCHES OF SNOW ACROSS OUR NORTHERN COUNTIES AND LESS THAN AN INCH TO OUR CENTRAL AND SOUTHERN COUNTIES WHERE ACCUMULATION MAY BE CUT DOWN BY THE PRESENCE OF SLEET. FREEZING RAIN SHOULD CAUSE A PROBLEM ONLY ACROSS OUR NORTHERN COUNTIES WHERE UP TO A TENTH OF AN INCH OF ICE MAY ACCUMULATE ON TOP OF THE NEW SNOWFALL. IT CONTINUES TO APPEAR AS THOUGH THE PRECIPITATION WILL CHANGE TO ALL RAIN FOR WEDNESDAY. A BIT OF DRYING MAY BEGIN TO WORK ITS WAY DOWN FROM THE NORTHWEST ON WEDNESDAY AFTERNOON. IT SEEMS POSSIBLE THAT SOME LOCATIONS, ESPECIALLY IN THE CENTRAL AND SOUTHERN PARTS OF OUR FORECAST AREA MAY PICK UP A HALF INCH TO AN INCH OF RAINFALL DURING THE PERIOD. THE RAIN IN COMBINATION WITH SNOWMELT AND THE FROZEN GROUND, ALONG WITH ICE MOVEMENT IN AREA WATERWAYS MAY RESULT IN A BIT OF MINOR FLOODING. THE MODELS ARE COMING TOGETHER ON THE IDEA OF A WAVE OF LOW PRESSURE RIDING ALONG THE SLOW MOVING COLD FRONT. IT SHOULD BRING US ANOTHER ROUND OF PRECIPITATION FOR WEDNESDAY NIGHT INTO THURSDAY. AS COLD AIR FILTERS DOWN INTO OUR REGION FROM THE NORTH AND NORTHWEST, THE PRECIPITATION TYPE WILL LIKELY TRANSITION TO SNOW. THERE IS ENOUGH SPREAD IN THE GUIDANCE SOLUTIONS TO MAKE THE DETAILS A BIT UNCERTAIN AT THIS POINT. HOWEVER, IT IS LOOKING INCREASINGLY POSSIBLE THAT WE WILL SEE ACCUMULATING SNOW IN MUCH OF OUR FORECAST AREA AT THAT TIME. HIGH PRESSURE FROM THE WEST IS ANTICIPATED TO BRING DRY WEATHER AND BELOW NORMAL TEMPERATURES FOR THURSDAY NIGHT INTO SATURDAY NIGHT. THE 0000 UTC GFS AND THE 0000 UTC ECMWF ARE BOTH SUGGESTING THE POTENTIAL FOR PRECIPITATION TO BE NEARING OUR REGION FROM THE SOUTHWEST ON SUNDAY DUE TO A WEAK AREA OF LOW PRESSURE ALONG WITH A WARM FRONT. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. IFR CONDITIONS PERSIST ACROSS THE TAF SITES EARLY THIS MORNING. AS A FRONTAL BOUNDARY MAKES ITS WAY ACROSS THE ARE AROUND DAYBREAK, CONDITIONS SHOULD IMPROVE TO MVFR THEN VFR. ONCE VFR CONDITIONS RETURN, THEY SHOULD REMAIN ACROSS THE TAF SITES THROUGH THE PERIOD. LIGHT WINDS THIS MORNING WILL INCREASE BEHIND THE FRONTAL BOUNDARY OUT OF THE WEST-NORTHWEST. GUSTY WINDS ARE EXPECTED TODAY WITH GUSTS AROUND 20-25 KNOTS EXPECTED. GUSTS SHOULD DROP OFF AROUND SUNSET, THROUGH A STEADY BREEZE WILL LIKELY REMAIN THROUGH THE EVENING BEFORE BECOMING LIGHT AND VARIABLE OVERNIGHT. OUTLOOK... TUESDAY...CONDITIONS LOWERING TO MVFR AND IFR IN THE AFTERNOON, AS SNOW AND SLEET BUILD INTO OUR REGION. TUESDAY NIGHT...MVFR AND IFR CONDITIONS WITH A WINTRY MIX OF PRECIPITATION CHANGING TO RAIN FROM SOUTH TO NORTH. THE RAIN MAY BE MODERATE TO HEAVY AT TIMES. LOW LEVEL WIND SHEAR IS POSSIBLE DUE TO A SOUTHWESTERLY LOW LEVEL JET THAT IS FORECAST TO DEVELOP OVERHEAD. WEDNESDAY...MVFR AND IFR CONDITIONS IN RAIN. THE RAIN MAY BE MODERATE TO HEAVY AT TIMES, ESPECIALLY SOUTH OF KPHL. WEDNESDAY NIGHT...MVFR AND IFR CONDITIONS IN RAIN, MIXING WITH THEN CHANGING TO SNOW FROM NORTH TO SOUTH. THURSDAY...MVFR AND IFR CONDITIONS IN MORNING SNOW. CONDITIONS IMPROVING GRADUALLY TO VFR WITH A LESSING CHANCE OF SNOW IN THE AFTERNOON. THURSDAY NIGHT AND FRIDAY...MAINLY VFR. && .MARINE... SMALL CRAFT ADVISORY REMAINS IN EFFECT ON THE WATERS FOR TODAY INTO TONIGHT AS WINDS WILL INCREASE BEHIND A FRONTAL BOUNDARY THAT WILL CROSS THE WATERS THIS MORNING. AN OCCASIONAL GUSTY AROUND 34/35 KNOTS IS POSSIBLE AROUND MIDDAY, BUT WE ARE NOT CONFIDENT ON GALE FORCE GUSTS BEING FREQUENT ENOUGH TO NEED A WARNING AT THIS TIME. AS HIGH PRESSURE BUILDS INTO THE AREA OVERNIGHT, WINDS WILL DIMINISH BELOW ADVISORY LEVELS. OUTLOOK.. TUESDAY...NO MARINE HEADLINES ARE ANTICIPATED. TUESDAY NIGHT AND WEDNESDAY...A SMALL CRAFT ADVISORY MAY BE NECESSARY DUE TO A GUSTY SOUTH TO SOUTHWEST WIND. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...A SMALL CRAFT ADVISORY MAY BE NEEDED TO DUE TO GUSTY NORTHWEST WIND. FRIDAY...NO MARINE HEADLINES ARE ANTICIPATED. && .HYDROLOGY... THE NEXT ROUND OF PRECIPITATION IS FORECAST TO MOVE INTO OUR AREA ON TUESDAY AFTERNOON AND IT WILL CONTINUE INTO WEDNESDAY AND THURSDAY. THIS MIDWEEK EVENT APPEARS TO START AS A WINTRY MIX BEFORE CHANGING OVER TO RAIN AS TEMPERATURES RISE WELL ABOVE FREEZING ON WEDNESDAY. THE QPF AMOUNTS FOR TUESDAY INTO WEDNESDAY FAVOR THE 0.25 TO 0.75 INCH RANGE. THE COMBINATION OF THE BRIEF WARM-UP ON WEDNESDAY, LOCALLY MODERATE TO HEAVY RAINFALL, MELTING SNOW, A FROZEN GROUND, AND ABOVE NORMAL ICE IN CREEKS, STREAMS, AND RIVERS COULD LEAD TO INCREASED RUNOFF AND POSSIBLE FLOODING. WHERE THE DEPTH OF THE SNOWPACK IS GREATEST (IN NE PA AND N NJ), RAPID SNOWMELT IS NOT EXPECTED SINCE TEMPS WILL NOT RISE AS SHARPLY AS IN AREAS TO THE SOUTH. INCREASED FLOW 0N AREA CREEKS, STREAMS, AND RIVERS COULD ALSO START TO MOVE ICE, AND IN A WORST CASE SCENARIO, CREATE RESTRICTIONS OR JAMS. CONTINUE TO MONITOR THE FORECAST. KEEP IN MIND THAT SNOWMELT AND WARMTH BY THEMSELVES TYPICALLY DO NOT CAUSE FLOODING. THE AMOUNT OF RAIN THAT WE RECEIVE WILL BE THE DETERMINING FACTOR. THE RAIN IS FORECAST TO CHANGE BACK TO SNOW ON WEDNESDAY NIGHT. && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EST TUESDAY FOR ANZ430-431- 450>455.
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&& $$ SYNOPSIS...IOVINO NEAR TERM...KLEIN/ROBERTSON SHORT TERM...ROBERTSON LONG TERM...IOVINO AVIATION...IOVINO/ROBERTSON MARINE...IOVINO/ROBERTSON HYDROLOGY...STAFF

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