Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 270550 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1250 AM EST THU NOV 27 2014 .SYNOPSIS... A COASTAL LOW WILL QUICKLY MOVE TO THE NORTHEAST OVERNIGHT. HIGH PRESSURE IS FORECAST TO BUILD ACROSS THE EAST COAST FRIDAY INTO EARLY SATURDAY, BEFORE SQUEEZING TO THE SOUTH SATURDAY NIGHT. A COLD FRONT IS EXPECTED TO SAG DOWN ACROSS THE AREA SUNDAY NIGHT, BEFORE SLOWLY MOVING THROUGH THE AREA MONDAY INTO MONDAY NIGHT. HIGH PRESSURE WILL THEN RETURN TO THE NORTHEAST FOR TUESDAY, FOLLOWED BY ANOTHER POTENTIAL FRONTAL SYSTEM WEDNESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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THE LOW WAS CENTERED ABOUT 75 MILES EAST OF CAPE COD AROUND MIDNIGHT AND IT SHOULD REACH NOVA SCOTIA AROUND DAYBREAK. THE LINGERING MOISTURE WILL CONTINUE TO ERODE SLOWLY DURING THE NIGHT AS THE RELATIVELY LIGHT WEST NORTHWEST WIND BRINGS DRY AIR INTO OUR REGION. TEMPERATURES ARE EXPECTED TO FALL ONLY A FEW DEGREES FROM THEIR MIDNIGHT VALUES WITH LOWS FORECAST TO RANGE FROM THE MIDDLE AND UPPER 20S IN THE NORTH TO THE LOWER 30S IN THE SOUTH. LIGHT SHOWERS WERE OCCURRING IN EXTREME EASTERN PENNSYLVANIA AND IN NEW JERSEY AROUND MIDNIGHT. THE PRECIPITATION WAS IN THE FORM OF SNOW IN THE ELEVATED TERRAIN UP NORTH AND IT WAS RAIN ELSEWHERE. THE PRECIPITATION WILL CONTINUE TO DRIFT EASTWARD AND OUT OF OUR REGION BEFORE DAYBREAK. LITTLE ADDITIONAL SNOW ACCUMULATION IS ANTICIPATED.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 AM FRIDAY/...
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THE COASTAL LOW THAT IS IMPACTING THE AREA TODAY WILL TRACK NORTHEASTWARD INTO THE CANADIAN MARITIMES ON THURSDAY. THE TRAILING SURFACE TROUGH/COLD FRONT IS FORECAST TO MOVE OFF THE NJ COAST AND THROUGH THE DELMARVA. THE 12Z GFS AND ECMWF HINT AT A WEAK WAVE OF LOW PRESSURE DEVELOPING ON THE LEE SIDE OF THE BLUE RIDGE MOUNTAINS BY 12Z THURSDAY. THIS LOW WOULD THEN MOVE EAST- NORTHEAST OFF THE NC COAST DURING THE AFTERNOON. A FEW SHOWERS NORTH OF THIS LOW MAY BRUSH THE DELMARVA DURING THE DAY. BOUNDARY LAYER THERMAL PROFILES MARGINALLY SUPPORTIVE OF A SNOW PERHAPS MIXING IN WITH THE RAIN BUT NO ACCUMULATIONS EXPECTED WITH SURFACE TEMPERATURES NEAR 40F. OTHERWISE, CLOUDS WILL LINGER ACROSS THE AREA FOR MOST OF THE DAY WITH THE UPPER TROUGH PROGRESSING EASTWARD ACROSS THE MID ATLANTIC AND NORTHEAST STATES. USED A BLEND OF THE MAV/MET GUIDANCE FOR TEMPS, GIVING US HIGHS IN THE 30S FROM I-95 WEST AND LOWER 40S TO THE EAST.
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&& .LONG TERM /FRIDAY THROUGH THURSDAY/...
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THURSDAY NIGHT IS EXPECTED TO BE DRY, WITH THE EXCEPTION OF A FEW LAKE EFFECT SNOW SHOWERS THAT MAY MAKE THEIR WAY ACROSS OUR NORTHERN AREAS. THEY WOULD BE QUITE ISOLATED, SO WE ONLY CARRY 20 POPS. ON FRIDAY, HIGH PRESSURE BEGINS TO BUILD ACROSS THE EAST COAST, BEFORE SQUEEZING TO OUR SOUTH AND EAST BY SATURDAY NIGHT. MODEL GUIDANCE IS INDICATING A COUPLE OF SHORT WAVE/VORTICITY IMPULSES SLIDING ACROSS THE AREA, ALONG WITH AN INCREASE IN MOISTURE ALOFT ACROSS THE NORTHERN AREAS. THERE IS SOME TIMING DIFFERENCES, BUT WE WILL KEEP A SLIGHT CHANCE OF SHOWERS ACROSS OUR NORTHWESTERN ZONES WHERE THEY HAVE A BETTER CHANCE OF SQUEEZING OUT SOME MOISTURE. ANYTHING THAT WOULD FALL IS EXPECTED TO BE LIGHT. ON SUNDAY, WE WILL BE IN BETWEEN THE HIGH TO OUR EAST AND AN APPROACHING COLD FRONT. ANOTHER WEAK SHORT WAVE/VORTICITY IMPULSE AND MOISTURE PLUME ALOFT SPREAD ACROSS THE NORTHERN HALF OF THE AREA SUNDAY, SO THERE REMAINS A SLIGHT CHANCE OF SHOWERS SUNDAY. A FRONTAL BOUNDARY IS EXPECTED TO APPROACH THE AREA SUNDAY NIGHT INTO MONDAY. THERE IS SOME DIFFERENCES WITH THIS BOUNDARY AS THE GFS IS FAST THAN THE ECMWF AND CANADIAN, AND DRIES THE PRECIP OUT SIMILAR TO THE CANADIAN, BUT UNLIKE THE ECMWF WHICH KEEPS SOME LIGHT PRECIP ACROSS THE AREA. WE WILL CONTINUE WITH CHANCE/SLIGHT CHANCE POPS, WITH THE HIGHEST ACROSS THE NORTHERN AND WESTERN AREAS WHERE THE PRECIP WOULD IMPACT FIRST BEFORE DRYING OUT. THE FRONT SHOULD PUSH TO OUR SOUTH AS HIGH PRESSURE BUILDS ACROSS THE NORTHEAST TUESDAY, BUT THERE COULD BE SOME LIGHT PRECIP THAT LINGERS ACROSS THE SOUTHERN AREAS IF THE FRONT STALLS CLOSER TO THE AREA. ANOTHER FRONTAL BOUNDARY IS EXPECTED TO AFFECT THE AREA AROUND NEXT WEDNESDAY. HOWEVER, THERE IS A QUESTION OF WHETHER THE FRONT SURGES THROUGH LIKE THE ECMWF, OR GETTING HUNG UP TO OUR NORTH LIKE THE GFS. WE WILL INTRODUCE A CHANCE/SLIGHT CHANCE OF POPS ACROSS THE AREA AS BOTH ARE SHOWING THE POTENTIAL FOR PRECIP.
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&& .AVIATION /06Z THURSDAY THROUGH MONDAY/...
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THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. THE MVFR CEILINGS NEAR THE COAST AROUND 0530Z SHOULD DRIFT OUT TO SEA BY 0700Z OR 0800Z. MEANWHILE, MVFR CEILING AND VISIBILITY RESTRICTIONS MAY AFFECT KRDG AND KABE THROUGH THE EARLY MORNING HOURS. A PERIOD OF MVFR VISIBILITY RESTRICTIONS IS POSSIBLE AT KTTN AND KMIV EARLY THIS MORNING. OTHERWISE, VFR CONDITIONS SHOULD PREVAIL FOR TODAY INTO TONIGHT AT OUR TAF SITES WITH A FAIR AMOUNT OF STRATOCUMULUS OVERHEAD DURING THE DAYLIGHT HOURS WITH BASES ABOVE 4000 FEET. A RELATIVELY LIGHT WEST NORTHWEST WIND IS EXPECTED THROUGH THE TAF PERIOD. SPEEDS SHOULD FAVOR THE 5 TO 10 KNOT RANGE. OUTLOOK... THURSDAY NIGHT...MOSTLY VFR. FRIDAY-MONDAY...MOSTLY VFR. WIND GUSTS 15-20 KNOTS EACH DAY; NW FRIDAY, SW SATURDAY & SUNDAY, AND NW ON MONDAY.
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&& .MARINE...
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WIND SPEEDS CONTINUE TO DIMINISH. AS A RESULT, THE SMALL CRAFT ADVISORY WILL BE DISCONTINUED ON DELAWARE BAY. THE SMALL CRAFT ADVISORY ON OUR OCEAN WATERS WILL REMAIN IN EFFECT UNTIL 400 PM, MAINLY FOR SEAS. OUTLOOK... THURSDAY NIGHT...WINDS ARE EXPECTED TO BE BELOW SMALL CRAFT ADVISORY LEVELS, BUT SEAS MAY REMAIN ELEVATED INTO THURSDAY NIGHT. FRIDAY-FRIDAY NIGHT...SUB-SMALL CRAFT ADVISORY CONDITIONS EXPECTED AS HIGH PRESSURE BUILDS OVER THE AREA. SATURDAY-SUNDAY...NEAR SMALL CRAFT ADVISORY CONDITIONS POSSIBLE AS HIGH PRESSURE PUSHES TO OUR SOUTH AND COLD FRONT APPROACHES LATE ON SUNDAY NIGHT.
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&& .CLIMATE... HERE ARE THE DAILY SNOWFALL RECORDS FOR OUR 4 SNOW CLIMATE SITES FOR NOVEMBER 26. ACY - TRACE IN 1977, 1957, 1955 PHL - 6.0 INCHES IN 1898 ILG - 0.1 INCHES IN 1950 ABE - 1.7 INCHES IN 1925. && .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ450>455.
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&& $$ SYNOPSIS...ROBERTSON NEAR TERM...IOVINO SHORT TERM...KLEIN LONG TERM...ROBERTSON AVIATION...IOVINO/ROBERTSON MARINE...IOVINO/ROBERTSON CLIMATE...STAFF

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