FXUS61 KPHI 260848
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
348 AM EST THU NOV 26 2009
.SYNOPSIS...
LOW PRESSURE WILL TRACK SLOWLY EASTWARD THROUGH THE GREAT LAKES
REGION TONIGHT AND THURSDAY AS ANOTHER LOW PRESSURE SYSTEM ORGANIZES
OFF THE EAST COAST. THESE SYSTEMS WILL MERGE ACROSS EASTERN NEW
ENGLAND FRIDAY. A STRONG COLD FRONT IS FORECAST TO MOVE THROUGH OUR
AREA FRIDAY MORNING. HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND AND
LAST INTO MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST BY
MONDAY NIGHT.
&&
.NEAR TERM /THROUGH TODAY/...
LOW CLOUDS AND FOG BLANKET THE FORECAST AREA THIS MORNING AS LOW
LEVEL MOISTURE IS HIGH AND THERE IS LITTLE IN THE WAY OF MIXING
OCCURRING. THE FOG IS QUITE VARIABLE WITH VSBYS DROPPING BELOW 1/2
MILE AT TIMES THEN RISING BACK TO 2 OR 3 MILES. I WILL NOT RAISE A
DENSE FOG ADVISORY ATTM...WITH CONDITIONS REMAINING QUITE VARIABLE.
A SPECIAL WEATHER STATEMENT MAY BE ISSUED TO ADDRESS THE FOG IN A
FEW LOCATIONS. THE FOG WILL REMAIN INTO THE MORNING BEFORE LIFTING
AS SOME DRIER AIR BEGINS TO MIX DOWN. OVERALL, TODAY WILL REMAIN
CLOUDY TO MOSTLY CLOUDY WITH TEMPERATURES IN THE MID 50S.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
THE APPROACHING UPPER VORTICITY LOBE AND THE SFC LOWS ADVANCING
TOWARD THE AREA WILL BRING AN INCREASED CHANCE FOR RAIN TO THE
AREA TONIGHT. THE RAIN CHANCES WILL DECREASE FROM SOUTH TO NORTH
ON FRIDAY AS DRIER AND COLDER AIR ADVANCE OVER THE AREA. A COLD
FRONT WILL ADVANCE OVER THE AREA FRIDAY MORNING AND GUSTY WEST TO
NORTHWEST WINDS WILL DEVELOP OVER THE AREA. GUSTS AROUND OR OVER 30
MPH ARE EXPECTED. HIGH TEMPERATURES WILL GENERALLY BE IN THE 40S
BUT THE GUSTY WINDS WILL MAKE IT FEEL MUCH COLDER. OVER THE SOUTHERN
POCONOS ANY LINGERING RAIN SHOWERS MAY MIX WITH SOME SNOW SHOWERS
FRIDAY NIGHT. NO ACCUMULATIONS ARE EXPECTED ATTM.
HIGH PRESSURE WILL BUILD IN LATER FRIDAY NIGHT AND SATURDAY. THIS
SHOULD PUT AN END TO ANY REMAINING PRECIPITATION ACROSS THE NORTH.
SKIES WILL CLEAR OUT FROM SOUTH TO NORTH AS THE DAY PROGRESSES.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AT THE UPPER LEVELS, A TROUGH IS FORECAST TO BE LIFTING TO OUR
NORTHEAST ON SATURDAY EVENING. MEANWHILE, A RIDGE IS EXPECTED TO
EXTEND FROM THE SOUTHEASTERN STATES UP OVER THE UPPER MISSISSIPPI
RIVER VALLEY AT THAT TIME. THE RIDGE AXIS SHOULD DRIFT TO THE EAST,
PASSING OVERHEAD ON SUNDAY AFTERNOON. WE ARE FORECAST TO BE ON THE
NORTHERN EDGE OF SURFACE HIGH PRESSURE FROM SATURDAY NIGHT INTO
EARLY MONDAY, WITH DRY WEATHER AND NEAR SEASONABLE TEMPERATURES
ANTICIPATED.
AN UPPER LEVEL TROUGH IS EXPECTED TO DROP ACROSS THE GREAT LAKES AND
THE NORTHEASTERN STATES DURING THE MONDAY AND TUESDAY TIME FRAME. IT
SHOULD PUSH A COLD FRONT THROUGH OUR REGION LATE ON MONDAY NIGHT OR
EARLY ON TUESDAY. AS A RESULT, WE HAVE MENTIONED A CHANCE FOR
SHOWERS. TEMPERATURES MAY BE LOW ENOUGH FOR SOME SNOW FLAKES UP IN
THE POCONOS AND IN FAR NORTHERN NEW JERSEY.
THE SURFACE COLD FRONT IS FORECAST TO STALL OFF THE COAST.
MEANWHILE, ANOTHER UPPER RIDGE SHOULD BUILD UP FROM THE SOUTHWEST
WITH ITS AXIS PASSING OVERHEAD ON WEDNESDAY. HIGH PRESSURE IS
EXPECTED TO PASS TO OUR NORTH AT THAT TIME, BRINGING DRY WEATHER TO
OUR NORTHERN COUNTIES FROM LATE TUESDAY INTO EARLY WEDNESDAY. WITH
THE SURFACE FRONT NEARBY, WE WILL KEEP SLIGHT CHANCE OR LOW CHANCE
POPS FOR OUR SOUTHERN COUNTIES.
AN UPPER TROUGH IS EXPECTED TO BEGIN APPROACHING FROM THE SOUTHWEST
ON WEDNESDAY, ALONG WITH SURFACE LOW PRESSURE FROM THE SOUTHWEST AND
SOUTH. AS A RESULT, WE HAVE INCLUDED CHANCE POPS FOR RAIN IN THE
FORECAST.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
IFR OR LIFR CONDITIONS WERE OBS AT MOST SITES. HOWEVER, A FEW TAF
SITES HAD MVFR CIGS AND VSBYS. THE REASON FOR THE IMPROVED
CONDITIONS HAD TO DO WITH HIGH CLOUDS MOVING OVER-TOP OF THE AREA AND
THESE CLOUDS KEPT DEEP FOG FROM FORMING OR STAYING IN PLACE.
ALTHOUGH THE HIGH CLOUDS WILL MOVE OFF TO THE EAST EARLY THIS
MORNING, CONDITIONS WILL BE VARIABLE FROM LIFR TO MVFR AT ALL SITES
AS THAT IS SCATTERED THROUGH THE REGION, TEMPORARILY MOVES ACROSS
THE TAF SITES.
SINCE THE FOG IS NOT WIDESPREAD, VSBYS SHOULD IMPROVE THIS MORNING
AND CIGS SHOULD ALSO SLOWLY IMPROVE. BY LATE MORNING, MVFR CIG ARE
FCST WITH VFR VSBY DEVELOPING.
A COLD FRONT WILL MOVE THROUGH FROM THE NW TONIGHT AND BE FOLLOWED
BY GUSTY NW WINDS. ALTHOUGH SOME PATCHY FOG COULD FORM THIS EVENING,
ONCE THE FRONT MOVES THROUGH, VSBY WILL BECOME UNRESTRICTED.
ALTHOUGH MVFR CIG MAY STILL LINGER WITH THE COLD AIR ADVECTION, ANY
LINGERING CIGS SHOULD INCREASE TO VFR.
ON FRIDAY, GUSTY NW WINDS WILL DOMINATE WITH MVFR CIGS AND POSSIBLE
SHOWERS. OVER THE HIGHER ELEVATIONS TO THE N OF RDG-ABE THERE MAY BE
SNOW SHOWERS IN THE AFTN WITH MVFR VSBY. WINDS SHOULD BECOME
SUSTAINED UP TO 20 KT WITH GUSTS UP TO 35 KT.
OUTLOOK...
HIGH PRESSURE SHOULD BUILD IN FROM THE WEST FOR SATURDAY, SUNDAY AND
MONDAY. GUSTY WINDS SHOULD CONTINUE THROUGH FRIDAY NIGHT AND THEN
DIMINISH DURING THE DAY SATURDAY.
&&
.MARINE...
SCA HAVE BEEN ISSUED FOR LATE TONIGHT AND GALE WARNINGS HAVE BEEN
ISSUED FOR FRIDAY AND FRIDAY NIGHT.
INITIALLY WE ARE IN A LIGHT WIND SITUATION WELL AHEAD OF THE COLD
FRONT TODAY. HOWEVER, ONCE A COLD FRONT MOVES THROUGH FROM THE NW
TONIGHT, WINDS WILL INCREASE DUE TO COLDER AIR ON WARMER WATERS AS
WELL AS AN INCREASED GRADIENT. INITIALLY THE GRADIENT ONLY SUPPORTS
WINDS TO 25 KT TONIGHT, BUT ON FRIDAY, THE GRADIENT SUPPORTS GUSTS
TO 35-40 KT AND PERHAPS AS HIGH AS 45 KT FRIDAY NIGHT.
THE GALES MAY CONTINUE INTO SATURDAY. HOWEVER, THE GRADIENT SLOWLY
RELAXES AND DUE TO THAT WINDS SHOULD DECREASE DURING SATURDAY AND
ESPECIALLY SAT NIGHT. BY SUNDAY THE THE COLD AIR SHOULD HAVE MOVED
AWAY AND A SW FLOW SHOULD BE OVER THE AREA ALLOWING THE WINDS TO
DROP UNDER 25 KT. THESE WINDS ARE FORECAST TO CONTINUE THROUGH
MONDAY.
ALSO, TIDES WILL BE WELL BELOW NORMAL WITH NEGATIVE DEPARTURES OF 1
TO 2 FT ON THE OCEAN LATE FRIDAY NIGHT AND 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...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
FRIDAY FOR ANZ430-431-450>455-470.
GALE WARNING FROM 6 AM FRIDAY TO 6 AM EST SATURDAY FOR ANZ430-
431-450>455.
&&
$$
SYNOPSIS...O'HARA
NEAR TERM...O'HARA
SHORT TERM...O'HARA
LONG TERM...IOVINO
AVIATION...STAUBER
MARINE...STAUBER
