Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 200748 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 348 AM EDT MON APR 20 2015 .SYNOPSIS...
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LOW PRESSURE LOCATED OVER THE GREAT LAKES EARLY THIS MORNING WILL CONTINUE TO MOVE NORTHWARD. THE LOW IS FORECAST TO PULL A WARM FRONT FROM THE SOUTH INTO OUR REGION TODAY FOLLOWED BY A COLD FRONT FROM THE WEST LATE TONIGHT. HIGH PRESSURE IS EXPECTED TO EDGE NORTHWARD INTO OUR REGION FOR TUESDAY INTO WEDNESDAY BEFORE ANOTHER COLD FRONT FROM THE NORTHWEST ARRIVES ON WEDNESDAY NIGHT. A SECONDARY COLD FRONT IS ANTICIPATED FOR LATE THURSDAY. HIGH PRESSURE SHOULD BUILD INTO OUR REGION GRADUALLY FROM THE NORTHWEST AND WEST DURING FRIDAY AND THE COMING WEEKEND AS STRONG LOW PRESSURE MEANDERS OFF THE SOUTHEAST COAST OF CANADA.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A WARM FRONT IS LOCATED SOUTH OF THE AREA ACROSS CENTRAL VIRGINIA AND IS SLOWLY TRYING TO LIFT NORTHWARD. NORTH OF THIS BOUNDARY, A LARGE AREA OF OVER-RUNNING PRECIPITATION IS OCCURRING, ENHANCED BY A SHORT WAVE TROUGH ALOFT LIFTING ACROSS THE AREA EARLY THIS MORNING. WITH PW VALUES AROUND 1.5-1.75 INCHES, THERE WILL BE WIDESPREAD MODERATE RAINFALL, WITH EMBEDDED HEAVIER SHOWERS. THIS MODERATE/HEAVY RAIN COULD LEAD TO SOME URBANIZED/POOR DRAINAGE TYPE FLOODING AND PONDING ON ROADWAYS. THE SHORT WAVE WILL MOVE INTO THE AREA AROUND SUNRISE, THEN PROGRESS NORTHWARD THROUGH THE MORNING HOURS. WE EXPECT THE SHOWERS ASSOCIATED WITH THE SHORT WAVE AND NORTH OF THE BOUNDARY TO PUSH NORTH OF THE AREA LATER IN THE MORNING AND INTO THE EARLY AFTERNOON. THE WARM FRONT MAY HAVE A TOUGH TIME LIFTING THROUGH THE AREA, AND WILL MOST LIKELY GET CAUGHT UP AND STALL ACROSS SOUTHEAST PENNSYLVANIA INTO SOUTHERN NEW JERSEY. THERE IS STILL A CHANCE OF SHOWERS THROUGH THE DAY, AND SOUTH OF THE WARM FRONT IN THE WARM SECTOR INSTABILITY WILL INCREASE. THIS COULD LEAD TO SOME SCATTERED THUNDERSTORM DEVELOP DURING THE AFTERNOON HOURS. IF THUNDERSTORMS DO DEVELOP, THEY COULD HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS AS WELL AS SMALL HAIL. OVERALL THERE SHOULD MOSTLY BE A BREAK IN ACTIVITY DURING THE AFTERNOON, BEFORE MORE SHOWER ACTIVITY WITH THE COLD FRONT DURING THE EVENING/OVERNIGHT. TEMPERATURES TODAY SHOULD VARY DEPENDING ON HOW FAR THE WARM FRONT LIFTS. NORTH OF THE FRONT, TEMPERATURES SHOULD ONLY GET INTO THE 50S AND 60S. SOUTH OF THE FRONT, TEMPERATURES SHOULD REACH THE MID-UPPER 70S, EVEN CLOSE TO 80 IN SOME AREAS, ESPECIALLY WHERE THE SUN COMES OUT.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
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THE COLD FRONT WILL BE APPROACHING THE AREA FROM THE WEST DURING THE EARLY EVENING, AND PROGRESS ACROSS THE AREA OVERNIGHT. WE EXPECT A LINE OF SHOWERS, WITH ISOLATED THUNDERSTORMS TO HAVE DEVELOPED TO OUR WEST DURING THE DAY ALONG AND AHEAD OF THE BOUNDARY. THESE SHOWERS WILL PROGRESS EASTWARD THROUGH THE EVENING AND INTO THE OVERNIGHT HOURS AS THE FRONT MOVES THROUGH. ALL SHOWER ACTIVITY IS EXPECTED TO HAVE MOVED TO OUR EAST BY SUNRISE TUESDAY.
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&& .LONG TERM /TUESDAY THROUGH SUNDAY/...
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A MID LEVEL LOW IS FORECAST TO BE LOCATED OVER LAKE SUPERIOR ON TUESDAY MORNING WITH A BROAD LONG WAVE TROUGH AFFECTING MUCH OF THE CENTRAL AND EASTERN PARTS OF THE COUNTRY. THE MID LEVEL LOW IS EXPECTED TO DRIFT EASTWARD AND IT SHOULD PASS OFF THE COAST OF NEW ENGLAND AND CANADA`S MARITIME PROVINCES ON FRIDAY AND FRIDAY NIGHT. WHILE THERE CONTINUES TO BE A SPREAD IN THE MODEL SOLUTIONS FOR THE WEEKEND, THE OVERALL TRENDS KEEP US UNDER THE INFLUENCE OF THE BROAD MID LEVEL TROUGH THROUGH THE BALANCE OF THE LONG TERM PERIOD. THE FORECAST PATTERN SHOULD RESULT IN A RETURN TO BELOW NORMAL TEMPERATURES. AFTERNOON READINGS SHOULD BE ABOUT 10 DEGREES BELOW NORMAL FOR THE PERIOD FROM THURSDAY THROUGH SUNDAY. THERE IS THE POTENTIAL FOR FROST, ESPECIALLY DURING THE EARLY MORNING HOURS OF SATURDAY WHEN A MOSTLY CLEAR SKY AND A RELATIVELY LIGHT WIND ARE ANTICIPATED. THERE IS A CHANCE OF SHOWERS ON TUESDAY AFTERNOON IN OUR NORTHWESTERN COUNTIES AS A MID LEVEL SHORT WAVE TROUGH LIFTS NORTHEASTWARD OVER OUR REGION. A COLD FRONT IS FORECAST TO APPROACH FROM THE NORTHWEST ON WEDNESDAY AND IT SHOULD PASS THROUGH OUR REGION ON WEDNESDAY NIGHT. AS A RESULT, WE WILL MENTION A CHANCE OF SHOWERS THROUGHOUT OUR REGION FOR THAT PERIOD OF TIME. THERE IS THE POTENTIAL FOR SOME SNOW FLAKES TOWARD THE END OF THE PRECIPITATION EVENT IN THE ELEVATED TERRAIN UP NORTH. A SECONDARY COLD FRONT IS EXPECTED TO ARRIVE LATE ON THURSDAY BUT IT SHOULD HAVE LIMITED MOISTURE ASSOCIATED WITH IT. WE HAVE MENTIONED ONLY A LOW OR SLIGHT CHANCE OF SHOWERS FOR OUR NORTHWESTERN COUNTIES. SURFACE HIGH PRESSURE IS ANTICIPATED TO GRADUALLY WORK ITS WAY INTO OUR REGION FROM THE NORTHWEST AND WEST FOR FRIDAY AND THE WEEKEND. WE HAVE NOT MENTIONED ANY PRECIPITATION FOR THE PERIOD FROM FRIDAY THROUGH SUNDAY.
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&& .AVIATION /07Z MONDAY THROUGH FRIDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. MVFR CONDITIONS HAVE OVERSPREAD THE AREA AS RAINFALL IS MOVING INTO THE AREA EARLY THIS MORNING. WE STILL EXPECT A PERIOD OF IFR CONDITIONS TO SPREAD ACROSS THE AREA AS WELL THROUGH SUNRISE. A WARM FRONT WILL LIFT TOWARD THE AREA DURING THE DAY. ONCE IFR CONDITIONS DEVELOP, THEY WILL LIKELY REMAIN INTO THE LATE MORNING/EARLY AFTERNOON, BEFORE BEGINNING TO LIFT AS THE WARM FRONT LIFTS INTO THE REGION. NORTH OF THE FRONT, LOWER CIGS WILL CONTINUE LONGER, BUT WHERE THE FRONT DOES LIFT AND PASS THROUGH, CIGS SHOULD IMPROVE TO MVFR OR VFR BY THE AFTERNOON. THERE IS A CHANCE FOR ISOLATED THUNDERSTORMS LATER THIS AFTERNOON SOUTH OF THE WARM FRONT, BUT CONFIDENCE ON WHEN/WHERE THEY OCCUR IS STILL LOW SO WE DID NOT INCLUDE THEM. ADDITIONAL SHOWERS ARE EXPECTED LATER THIS EVENING INTO THE OVERNIGHT HOURS AS A COLD FRONT APPROACHES AND MOVES ACROSS THE AREA. AGAIN, THERE MAY BE SOME THUNDERSTORMS ASSOCIATED WITH THE FRONT, BUT CONFIDENCE IS LOW SO WE DID NOT INCLUDE THEM. GUSTY EASTERLY WINDS WILL CONTINUE THROUGH THE MORNING HOURS. AS THE WARM FRONT LIFTS INTO THE AREA LATER THIS MORNING INTO THE AFTERNOON, WINDS WILL BECOME MORE SOUTHERLY. BEHIND THE COLD FRONT LATER TONIGHT, WINDS WILL SWING AROUND TO THE WEST AND BECOME GUSTY ONE AGAIN. WE HAVE KEPT LLWS IN THE TAFS FOR THE MORNING HOURS AS THERE REMAINS 50-55 KT WINDS AROUND 1,000-2,000 FEET. OUTLOOK... TUESDAY AND TUESDAY NIGHT...MAINLY VFR. WEDNESDAY AND WEDNESDAY NIGHT...MAINLY VFR. HOWEVER, SCATTERED RAIN SHOWERS MAY REDUCE CEILING AND VISIBILITY VALUES INTO THE MVFR RANGE AT TIMES. THURSDAY THROUGH FRIDAY...MAINLY VFR.
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&& .MARINE...
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SMALL CRAFT ADVISORY REMAIN ACROSS THE WATERS AS GUSTY EASTERLY WINDS REMAIN WELL NORTH OF A WARM FRONT TO THE SOUTH. AS THE WARM FRONT LIFTS INTO THE AREA, WINDS SHOULD BECOME MORE SOUTHERLY- SOUTHEASTERLY THROUGH THE DAY. THERE IS STRONG WINDS JUST ABOVE THE SURFACE, BUT WE EXPECT THE LOW LEVEL INVERSION ACROSS THE WATER TO PREVENT GALE FORCE WINDS TO DEVELOP. A COLD FRONT WILL MOVE ACROSS THE WATERS OVERNIGHT TONIGHT, SO WINDS WILL BECOME MORE WESTERLY BY TUESDAY MORNING. SEAS WILL CONTINUE TO BUILD TO AROUND 9 FEET THROUGH THIS MORNING, AND REMAIN ELEVATED THROUGH TONIGHT. OUTLOOK... TUESDAY...A SMALL CRAFT ADVISORY IS IN EFFECT FOR OUR OCEAN WATERS FOR WAVE HEIGHTS OF 5 TO 6 FEET AND THE POTENTIAL FOR LINGERING WIND GUSTS NEAR 25 KNOTS. TUESDAY NIGHT THROUGH THURSDAY NIGHT...NO MARINE HEADLINES ARE ANTICIPATED. FRIDAY...A SMALL CRAFT ADVISORY MAY BE NEEDED FOR GUSTY NORTHWEST WINDS.
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&& .TIDES/COASTAL FLOODING...
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TIDAL DEPARTURES WERE AROUND +0.4 FEET ALONG THE OCEANFRONT AROUND SUNDAY EVENING`S HIGH TIDE. THE MINOR FLOODING THRESHOLD WAS JUST REACHED AT SANDY HOOK AND WATER LEVELS FELL ONE TO TWO TENTHS OF A FOOT BELOW THE THRESHOLD AT ATLANTIC CITY, CAPE MAY AND LEWES. THE EASTERLY FLOW IS EXPECTED TO CONTINUE OVERNIGHT. A WARM FRONT LIFTING SLOWLY THROUGH OUR REGION SHOULD CAUSE THE WIND DIRECTION TO VEER TO THE SOUTHEAST THEN TO THE SOUTH TODAY. THE CHANGE IN WIND DIRECTION SHOULD TAKE PLACE LAST ALONG THE NORTHERN PART OF THE NEW JERSEY COAST. THE ASTRONOMICAL TIDES ON MONDAY MORNING ARE ABOUT 0.8 TO 0.9 FEET LOWER THAN THOSE ON SUNDAY EVENING. AS A RESULT, DEPARTURES OF +1.2 TO +1.4 FEET WOULD BE NEEDED TO CAUSE LOW END MINOR FLOODING. DEPARTURES ARE FORECAST TO REMAIN LESS THAN +1.0 FOOT AROUND HIGH TIDE, SO NO PROBLEMS ARE ANTICIPATED. WE WILL KEEP AN EYE ON THE FORECAST LEVELS FOR THE NORTHERN PART OF THE NEW JERSEY COAST FOR THIS EVENING`S HIGH TIDE. THERE COULD BE SOME MINOR FLOODING THERE IF THE WIND SHIFT IS SLOWER THAN EXPECTED.
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&& .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR ANZ450>455. SMALL CRAFT ADVISORY UNTIL 10 AM EDT THIS MORNING FOR ANZ430- 431.
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&& $$ SYNOPSIS...IOVINO NEAR TERM...ROBERTSON SHORT TERM...ROBERTSON LONG TERM...IOVINO AVIATION...IOVINO/ROBERTSON MARINE...IOVINO/ROBERTSON TIDES/COASTAL FLOODING...IOVINO

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