Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000 FXUS61 KPHI 170743 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 343 AM EDT THU APR 17 2014 .SYNOPSIS...
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HIGH PRESSURE WILL MOVE OUT OF NEW ENGLAND AND ACROSS THE CANADIAN MARITIMES BUT STILL EXTEND ACROSS THE EASTERN SEABOARD THROUGH EARLY FRIDAY. A FRONTAL BOUNDARY WILL MOVE ACROSS THE AREA FRIDAY NIGHT INTO SATURDAY MORNING, BEFORE HIGH PRESSURE REESTABLISHES ITSELF ACROSS EASTERN CANADA AND BUILDS SOUTHWARD ALONG THE EASTERN SEABOARD SUNDAY INTO MONDAY. ANOTHER FRONTAL BOUNDARY IS EXPECTED TO AFFECT THE AREA NEXT TUESDAY, FOLLOWED BY HIGH PRESSURE FOR THE MIDDLE OF NEXT WEEK.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAINLY CLEAR CONDITIONS CONTINUE ACROSS THE REGION THIS EVENING, WITH JUST A LITTLE CIRRUS STREAMING IN FROM THE WEST. WINDS HAVE DIMINISHED ACROSS THE CWA BUT SHOULD REMAIN IN THE 5 TO 10 MPH RANGE MOST OF THE NIGHT, VEERING FROM THE NORTH TO THE NORTHEAST. THE CLEAR SKIES AND LIGHTER WINDS, AS WELL AS A DRY AIRMASS IN PLACE, WILL ALLOW FOR GOOD RADIATING CONDITIONS, ESPECIALLY THROUGH THE OVERNIGHT. MINIMUM TEMPS STILL LOOK ON TRACK WITH THE LATEST GUIDANCE, BUT WE DID ADJUST HOURLY TEMPS AND DEWPOINTS USING THE LAV/LAMP GUIDANCE TO CAPTURE CURRENT TRENDS AND OBSERVATIONS. OTHERWISE, THE SFC HIGH PRES WILL CONT TO MOVE EWD THROUGH NY AND INTO NEW ENGLAND BEFORE MORNING. A SFC RIDGE EXTDS SWWD FROM THE CENTER ACROSS THE MID-ATL REGION BUT OUR FCST AREA REMAINS IN A PRES GRAD PATTERN WHICH SHOULD MAINTAIN NE TO E WINDS OVERNIGHT. IN SPITE OF THE WINDS HWVR...WITH CLEAR SKIES AND AN UNSEASONABLY COLD AIR MASS IN PLACE WE EXPECT TEMPS TO FALL BELOW FREEZING IN MOST AREAS FOR SEVERAL HOURS BETWEEN MIDNIGHT AND SUNRISE THURSDAY MORNING. HENCE WE MAINTAIN A FREEZE WARNING FOR AREAS IN SE PA...CNTRL/SRN NJ...AND NRN DELMARVA WHERE THE GROWING SEASON HAS BEGUN. THE MET/MAV/ECS GUIDANCE ARE IN GOOD AGREEMENT ON THE FREEZING TEMPS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/... FOR THURSDAY...THE SFC HIGH PRES RIDGE PRETTY MUCH REMAINS IN PLACE OVER THE EASTERN SEABOARD...WHICH IN COMBO WITH THE OFFSHORE FRONTAL TROF WILL MAINTAIN AN E/NE ONSHORE FLOW. FCST RH FOR THE LOWER TROP IS RATHER LOW...BUT THE PERSISTENT ONSHORE LOW-LVL FLOW MAY EVENTUALLY BRING IN SOME MOISTURE AND CLOUDINESS. THE AIR MASS TMRW SHOULD NOT BE AS COLD AS TODAY AND CAA IS REPLACED BY WAA. HENCE MAX TEMPS ON THURS SHOULD BE A FEW DEGREES WARMER THAN TODAY BUT STILL QUITE A BIT BELOW NORMAL FOR MID APRIL. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/...
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THE HIGH PRESSURE THAT HAS BEEN EXTENDING SOUTHWARD ACROSS THE EAST COAST FROM CANADA WILL BEGIN PULLING OUT OF THE AREA DURING THE DAY FRIDAY. AS THIS HAPPENS, OUR AREA WILL BE IN BETWEEN TWO FEATURES LATE FRIDAY INTO FRIDAY NIGHT; ONE BEING AN AREA OF LOW PRESSURE TO OUR SOUTH OFF THE SOUTHEAST COAST AND THE OTHER AN APPROACHING COLD FRONT. WITH THE PERSISTENT NORTHEAST FLOW ACROSS THE AREA, WE EXPECT A FAIR AMOUNT OF CLOUD COVER FRIDAY INTO FRIDAY NIGHT. THIS SHOULD HELP KEEP TEMPERATURES COOL THROUGH THE DAY FRIDAY, SO WE REMAIN BELOW NORMAL. THE SYSTEM TO OUR SOUTH IS EXPECTED TO REMAIN FAR ENOUGH TO OUR SOUTH TO PREVENT WIDESPREAD PRECIPITATION TO AFFECT THE AREA. HOWEVER, THERE REMAINS A SLIGHT CHANCE SOME LIGHT RAIN ON THE VERY FAR NORTHERN EDGE COULD EXTEND ACROSS OUR SOUTHEASTERN AREAS, SO WE WILL KEEP SLIGHT CHANCE POPS ACROSS OUR SOUTHEASTERN ZONES. SOUNDINGS INDICATE THAT THE VERTICAL MOISTURE IS RATHER SHALLOW, SO IT MAY BE MORE DRIZZLE, SO WE WILL INCLUDE CHANCE DRIZZLE WITH THE RAIN IN THE FORECAST LATE FRIDAY INTO FRIDAY NIGHT. THE AFOREMENTIONED COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA OVERNIGHT FRIDAY INTO SATURDAY MORNING. ALL GUIDANCE INDICATES THE PRECIPITATION DRYING OUT AS IT APPROACHES OUR AREA, SO WE HAVE REMOVED POPS FOR THE REMAINDER OF THE AREA AS WE NOW EXPECT A DRY FRONTAL PASSAGE. WE EXPECT DRY WEATHER TO BUILD IN ACROSS THE AREA SATURDAY BEHIND THE FRONTAL BOUNDARY AS HIGH PRESSURE BEGINS TO BUILD SOUTHWARD OUT OF CANADA. THE HIGH SHOULD SUPPRESS THE LOW TO OUR SOUTH BY SATURDAY SO THAT IT WOULDN`T HAVE AN EFFECT ON OUR AREA ANYMORE. THIS HIGH WILL REESTABLISH ITSELF ACROSS EASTERN CANADA AND BUILDS SOUTHWARD ALONG THE EASTERN SEABOARD AGAIN INTO SUNDAY AND MONDAY. THIS WILL CONTINUE TO PROVIDE DRY WEATHER OVER THE WEEKEND INTO MONDAY OF NEXT WEEK. WITH RIDGING ALOFT TAKING PLACE, TEMPERATURES WILL RETURN CLOSER TO NORMAL OVER THE WEEKEND INTO EARLY NEXT WEEK. ON TUESDAY, A COLD FRONT IS FORECAST TO APPROACH THE AREA FROM THE WEST. AN AREA OF LOW PRESSURE IS FORECAST TO DEVELOP AND STRENGTHEN ALONG THE BOUNDARY AS IT MOVES ACROSS THE AREA LATE TUESDAY INTO TUESDAY NIGHT. TUESDAY INTO TUESDAY NIGHT LOOKS TO BE THE NEXT CHANCE OF PRECIPITATION ACROSS THE AREA. THEREFORE WE HAVE CHANCE POPS ACROSS THE AREA DURING THIS TIME PERIOD. THIS LOW IS EXPECTED TO SLOWLY PULL TO OUR NORTHEAST THROUGH WEDNESDAY AS HIGH PRESSURE BEGINS TO BUILD SOUTHWARD OUT OF CANADA ONCE AGAIN. WEDNESDAY IS EXPECTED TO BE DRY, BUT SHOULD BE QUITE GUSTY WITH THE TIGHTENING PRESSURE GRADIENT.
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&& .AVIATION /08Z THURSDAY THROUGH MONDAY/...
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CLEAR SKIES AND VFR CONDS ARE EXPECTED FOR THE REST OF THIS EVENING AND TONIGHT. SOME LOW CLOUDS WITH BASES AROUND 3000 FT MAY DEVELOP ON THURS WITH ONSHORE LOW-LVL WINDS...MORE LIKELY FROM PHL SOUTH AND INTO THE AFTN...BUT OVERALL VFR CONDS SHOULD PREVAIL. THE CONTINUED ONSHORE FLOW INTO THURSDAY NIGHT COULD LEAD TO SUB- VFR CIGS, BUT CONFIDENCE ON THIS OCCURRENCE IS BELOW AVERAGE AND WE ONLY HINTED AT THIS IDEA IN THE TAFS. OTHERWISE, WINDS WILL CONTINUE TO VEER FROM A NORTHERLY DIRECTION TO A MORE NORTHEAST DIRECTION THIS EVENING AND OVERNIGHT, BECOMING MORE EASTERLY DURING THURSDAY. SPEEDS WILL AVERAGE 5 TO 10 KT OVERNIGHT AND MORE IN THE 10 TO 15 KT RANGE DURING THURSDAY...SOMEWHAT STRONGER TOWARD THE COAST AND WEAKER INTO ERN PA. SOME GUSTINESS TO AROUND 20 KT MAY OCCUR FROM ABOUT MID-MORNING ONWARD, ESPECIALLY AT KACY, BUT THIS WAS NOT INCLUDED IN THE TAFS AT THIS TIME. OUTLOOK... FRIDAY-FRIDAY NIGHT...MVFR CIGS POSSIBLE, ESPECIALLY CLOSER TO THE COAST. SATURDAY-MONDAY...MOSTLY VFR. GUSTY N-NW WINDS 15-20 KNOTS SATURDAY.
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&& .MARINE...
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AS BEST WE CAN TELL...WINDS OVER DEL BAY AND NJ/DE COASTAL WATERS APPEAR TO HAVE DIMINISHED BELOW SCA THRESHOLD. HOWEVER...SEAS REMAIN AROUND 5 FEET SO A SCA CONTINUES FOR ALL COASTAL WATERS. ALSO...THE SFC PRES GRADIENT IS FCST TO INCREASE OVERNIGHT RESULTING IN INCREASING NE WINDS AND GRADUALLY BUILDING SEAS. SCA CONDS ARE LIKELY TO CONTINUE THROUGH THURSDAY AND BEYOND. OUTLOOK... FRIDAY-FRIDAY NIGHT...SEAS LIKELY TO REMAIN 5 FEET OR GREATER ON THE OCEAN THROUGH EARLY FRIDAY NIGHT, THEN BEGIN TO SUBSIDE. SATURDAY...SUB-SMALL CRAFT ADVISORY CRITERIA EXPECTED. SATURDAY NIGHT-SUNDAY...WINDS AND SEAS INCREASING TO SMALL CRAFT ADVISORY CRITERIA OVERNIGHT SATURDAY AND CONTINUE INTO SUNDAY, ESPECIALLY ON OCEAN. SUNDAY NIGHT-MONDAY...A RETURN TO SUB-SMALL CRAFT ADVISORY CRITERIA EXPECTED SUNDAY NIGHT.
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&& .PHI WATCHES/WARNINGS/ADVISORIES...
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PA...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR PAZ060-101>103-106. FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR PAZ060-070- 101>104-106. NJ...FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR NJZ012-013-015-017>022-027. FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR NJZ012-013- 015>023-027. DE...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR DEZ001>003. MD...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MDZ008-012-015- 019-020. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR ANZ450>455. SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO MIDNIGHT EDT TONIGHT FOR ANZ431.
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&& $$ SYNOPSIS...ROBERTSON NEAR TERM...DRAG SHORT TERM...DRAG LONG TERM...ROBERTSON AVIATION...DRAG/ROBERTSON MARINE...DRAG/ROBERTSON

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