499
FXUS61 KPHI 271303
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
803 AM EST FRI NOV 27 2009
SYNOPSIS
AN AREA OF LOW PRESSURE MOVING INTO NEW ENGLAND TODAY WILL MERGE
WITH ANOTHER LOW ARRIVING FROM THE WEST AND INTENSIFY. THIS LOW
WILL USHER IN COLDER AND DRIER ACROSS THE AREA ON GUSTY WINDS
TODAY. HIGH PRESSURE WILL BUILD IN ACROSS THE AREA FROM THE SOUTH
DURING THE WEEKEND. ANOTHER LOW WILL APPROACH THE AREA EARLY NEXT
WEEK.
NEAR TERM /UNTIL 6 PM THIS EVENING/
AN AREA OF DEEPENING LOW PRESSURE EAST OF LONG ISLAND AT 12Z WILL
CONTINUE TO MOVE NORTHWARD THROUGH THE DAY. THIS WILL CONTINUE TO
TIGHTEN UP THE PRESSURE GRADIENT AND USHER IN COLDER AIR. A SHARP
UPPER-LEVEL TROUGH CONTINUES TO SLIDE INTO THE NORTHEAST AND MID
ATLANTIC AND RADAR IMAGERY SHOWERS A BAND OF SHOWERS WITH THIS
UPPER-LEVEL TROUGH. WE RECEIVED A REPORT FROM CARBON COUNTY,
PENNSYLVANIA WITH LIGHT SNOW OCCURRING AT AND ABOVE 1500 FEET.
BASED ON THE CAA AND THIS REPORT, SOME SNOW WAS ADDED TO THE
HIGHER TERRAIN OF CARBON AND MONROE COUNTIES WITH LITTLE
ACCUMULATION INDICATED FOR NOW DURING THE DAY. ELSEWHERE, SOME
RAIN SHOWERS WILL PUSH EASTWARD THROUGH THE MORNING WITH THE AREA
OF MORE CONCENTRATED RAIN ACROSS OCEAN COUNTY, NEW JERSEY
GRADUALLY PIVOTING OUT TO SEA. PLACING POPS IS TRICKY TODAY GIVEN
THE RADAR DEPICTION, HOWEVER WE ADJUSTED THEM BASED ON TRENDS THUS FAR.
THE HOURLY GRIDS WERE UPDATED TO REFLECT COOLER TEMPERATURES AND
LOWER DEW POINTS. TEMPERATURES MAY NOT RISE MUCH MORE TODAY AS THE
CAA CONTINUES. A GUSTY NORTHWEST WIND WILL CONTINUE THROUGH THE
DAY, AND WE WILL TAKE A CLOSER LOOK AT A POSSIBLE WIND ADVISORY
/MAINLY FOR TONIGHT/ LATER ON AS WE EXAMINE THE 12Z MODEL DATA.
SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/
COLD TEMPERATURES AND GUSTY WINDS WILL CONTINUE TONIGHT AND
EARLY SATURDAY. THE LAST REMNANTS OF MOISTURE CIRCULATING AROUND
THE DEPARTING SYSTEM MAY CREATE SNOW SHOWERS ACROSS THE POCONOS
TONIGHT WITH CHC POPS IN THERE FOR NOW.
FAIR WEATHER WILL BE ACROSS THE AREA FOR THE REMAINDER OF THE
SHORT TERM PERIOD. THE DEEP LOW WILL PULL FAR ENOUGH AWAY FOR
WINDS TO DIMINISH LATER SATURDAY. HIGH PRESSURE OVER THE SOUTHERN
STATES WILL NOSE NORTHWARD INTO TOUR AREA. HIGH TEMPERATURES ON
SUNDAY WILL BE 5 DEGREES OR SO HIGHER ON SUNDAY THAN ON SATURDAY.
READINGS BOTH DAYS IN THE 50S BY IN LARGE...WITH SOME 40S OVER THE
SOUTHERN POCONOS ON SATURDAY.
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
ON SUNDAY NIGHT, AN UPPER LEVEL TROUGH IS FORECAST TO BEGIN DIGGING
OVER THE GREAT LAKES REGION. THE TROUGH AXIS SHOULD PUSH TO THE
EAST, PASSING ACROSS THE NORTHEASTERN STATES ON TUESDAY. A SURFACE
COLD FRONT, ASSOCIATED WITH THE TROUGH, SHOULD PASS THROUGH OUR
REGION LATE ON MONDAY. WE WILL MENTION A CHANCE FOR SHOWERS FROM
MONDAY AFTERNOON INTO MONDAY NIGHT. IT COULD BE COLD ENOUGH FOR SOME
SNOW FLAKES UP NORTH.
WE MAY HOLD ON TO SOME CLOUDS AND SHOWERS, ESPECIALLY IN THE NORTH,
IN THE COLD ADVECTION ON TUESDAY.
HIGH PRESSURE IS ANTICIPATED TO BUILD ACROSS OUR REGION ON TUESDAY
NIGHT AND WEDNESDAY, BRINGING A PERIOD OF DRY WEATHER WITH
SEASONABLE TEMPERATURES.
THE CONSENSUS SEEMS TO BE THAT THE OPERATIONAL 1200 UTC GFS IS A BIT
FAST AND OVERDONE WITH THE LOW FOR THURSDAY. WE WILL FAVOR THE 1200
UTC ECMWF AND HPC SOLUTIONS. AS A RESULT, WE WILL FORECAST
PRECIPITATION TO MOVE INTO OUR REGION ON WEDNESDAY NIGHT AND
CONTINUE IT INTO THURSDAY. WITH BORDERLINE TEMPERATURES EXPECTED UP
NORTH, WE COULD SEE SOME ICE IN THE POCONOS AND FAR NORTHERN NEW
JERSEY.
AVIATION /13Z FRIDAY THROUGH TUESDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
WINDS WILL GUST 25-30 KT TODAY. WINDS SHOULD THEN CONTINUE TO
INCREASE TONIGHT WITH SUSTAINED WINDS OF 20 KT AT TIMES AND GUSTS
TO 35 AND PERHAPS 40 KT.
STRATOCU OF 2-3 THSD FT SHOULD MOSTLY PREVAIL. SHOWERS WILL
SPREAD EAST THROUGH THE REGION THEN OFF THE COAST SAT MORNING. ANY
SHOWERS COULD SEE CIGS ARND 15 HND FT AND LOCAL VSBY OF 3-5 MI.
THE SHOWERS MIGHT LINGER UNTIL 16Z, OTHERWISE DRY WEATHER IS
FORECAST FOR LATER IN THE MORNING AND AFTN WITH VFR CIGS.
OUTLOOK...
GUSTY WINDS WILL CONTINUE THROUGH SATURDAY AND THEN DECREASE
SATURDAY NIGHT. OTHERWISE, NO SIGNIFICANT WEATHER IS FORECAST
THROUGH WED.
MARINE
GALES ARE NOW IN EFFECT THROUGH SATURDAY. THE GALE FORCE WINDS
SHOULD DEVELOP LATE THIS MORNING OR THIS AFTN. THE WINDS WILL THEN
INCREASE TONIGHT AND PEAK OUT SATURDAY MORNING. HOWEVER, GALE FORCE
WINDS SHOULD CONTINUE THROUGH SAT BEFORE FINALLY COMING DOWN SAT
NIGHT.
THE STRONG GUSTY WINDS ARE A RESPONSE TO INTENSIFYING LOW PRESSURE
OFF THE NEW ENGLAND COAST AND COLD AIR MOVING OVER THE RELATIVELY
WARMER WATERS OF THE OCEAN AND DELAWARE BAY.
WIND GUSTS ARE EXPECTED TO REACH 45 KT LATE TONIGHT AND SAT MORNING
AND THERE IS THE POSSIBILITY OF OCCASIONAL GUSTS TO STORM FORCE ON
THE OCEAN EARLY SAT.
WINDS SHOULD DIMINISH BELOW GALES SAT NIGHT AND TO BELOW 25 KT ON
SUNDAY. WINDS AND OR SEAS MIGHT REACH SCA CRITERIA AGAIN LATER
MONDAY INTO TUESDAY AS A COLD FRONT APPROACHES THE REGION ON MONDAY
AND THEN IN THE COLD AIR ADVECTION BEHIND THE FRONTAL BOUNDARY ON
TUESDAY.
ALSO, TIDES SHOULD DROP TO BELOW NORMAL LEVELS WITH NEGATIVE
DEPARTURES OF 1 TO 2 FT FORECAST SATURDAY. HOWEVER, THESE DEPARTURES
DO NOT APPEAR LARGE ENOUGH FOR ANY LOW WATER ADVISORIES.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...GALE WARNING UNTIL 6 PM EST SATURDAY FOR ANZ430-431-450>455.
SYNOPSIS...GORSE/O'HARA
NEAR TERM...GORSE/O'HARA
SHORT TERM...O'HARA
LONG TERM...IOVINO
AVIATION...STAUBER
MARINE...STAUBER
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