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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 041411
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
911 AM EST WED DEC 4 2013

.SYNOPSIS...
-- Changed Discussion --
A WEAK RIDGE OF HIGH PRESSURE ACROSS THE REGION THIS MORNING WILL
MOVE TO THE EAST. LOW PRESSURE OVER THE PLAINS STATES WILL
STRENGTHEN AND MOVE INTO THE UPPER GREAT LAKES REGION BY THURSDAY.
ITS ASSOCIATED FRONTS WILL AFFECT THE AREA THURSDAY AND FRIDAY. A
WEAK WAVE OF LOW PRESSURE WILL MOVE ALONG THE FRONT FRIDAY NIGHT
AND SATURDAY. ANOTHER AREA OF LOW PRESSURE WILL AFFECT THE AREA
SUNDAY AFTERNOON THROUGH TUESDAY.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
NO BIG CHANGES WITH THE NEXT UPDATE. WE DID ADD SOME LOW POPS FOR
SUSSEX COUNTY DE AND THE ADJACENT COASTAL WATERS AS SHOWERS HAVE
JUST EDGED INTO OUR CWA. MORNING SOUNDINGS ARE SHOWING A PRETTY
STEEP INVERSION AND THE WIND FLOW IN GENERAL IS GOING TO BE WEAK.
THERE IS POTENTIAL TO GET WARMER THAN CURRENT FCST IF WINDS BECOME
STRONGER THAN EXPECTED. WE EDGED MAX TEMPS UP SLIGHTLY BECAUSE OF
THIS.

WEAK HIGH PRESSURE TO OUR SOUTHEAST WILL REMAIN TO OUR SOUTH TODAY
AS SLIGHT RIDGING ALOFT BUILDS ACROSS THE AREA DURING THE DAY. THIS
WILL ALLOW THICKNESSES TO RISE ACROSS THE AREA, IN TURN ALLOWING
HIGHS TODAY TO WARM A COUPLE OF DEGREES WARMER THAN TUESDAY. A
MAV/MET/MOSGUIDE BLEND WAS TAKEN FOR DAYTIME HIGHS.

MID-HIGH LEVEL CLOUDS WILL START OFF THE DAY, BEFORE LOWER CLOUDS
MOVE INTO THE AREA LATER THIS AFTERNOON AS A SHORT WAVE/VORTICITY
IMPULSE AND WEAK WARM FRONT APPROACH FROM THE SOUTHWEST. THERE ARE
SOME SCATTERED SHOWERS TO OUR SOUTH ACROSS VIRGINIA AND NORTH
CAROLINA, BUT MOST GUIDANCE KEEPS THIS AREA OF SHOWERS TO OUR
SOUTH. FOR NOW WE WILL KEEP THE WEATHER DRY FOR THE DAYTIME HOURS,
ALTHOUGH WE WILL WATCH THESE SHOWERS TO OUR SOUTH. EVEN IF THEY
MAKE IT ACROSS OUR SOUTHERN AREAS, THEY ARE VERY LIGHT.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AN AREA OF LOW PRESSURE WILL LIFT INTO THE GREAT LAKES REGION
TONIGHT INTO THURSDAY MORNING. A WEAK WARM FRONT IS EXPECTED TO LIFT
ACROSS OUR REGION OVERNIGHT AS A WEAK SHORT WAVE/VORTICITY IMPULSE
MOVES ACROSS THE AREA AS WELL. AHEAD OF THIS WARM FRONT, AN
EAST-SOUTHEAST FLOW WILL KEEP FAIRLY MOIST LOW-LEVEL AIR ACROSS THE
AREA. AS THESE FEATURES MOVE ACROSS THE AREA, IT IS POSSIBLE THAT
SOME LIGHT RAIN AND/OR DRIZZLE COULD DEVELOP. THE GOOD NEWS IS THE
TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING SO FREEZING
RAIN/DRIZZLE IS NOT ANTICIPATED AT THIS TIME.

OVERNIGHT LOWS MAY OCCUR EARLY IN THE NIGHT AS TEMPERATURES COULD
RISE AFTER MIDNIGHT ONCE THE WARM FRONT BEGINS TO LIFT THROUGH THE
AREA. WE FOLLOWED A BLEND OF THE MAV/MET MOS FOR TEMPERATURES.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
AN UPPER RIDGE ALONG THE EAST COAST AND A TROUGH OUT WEST WILL KEEP
THE STORM TRACK NEAR THE MIDDLE ATLANTIC THIS WEEKEND AND INTO EARLY
NEXT WEEK. THERE ARE SEVERAL SYSTEMS TO DEAL WITH AND TEMPERATURES
WILL EVENTUALLY BECOME COLD ENOUGH TO BRING FROZEN/FREEZING PCPN TO
THE REGION.

THU...DEEP LOW PRESSURE ACROSS MI WILL BRING ITS ASSD WARM FRONT
ACROSS THE AREA...POPS WILL FAVOR THE NRN AREAS WITH SLGT CHC POPS
ACROSS THE PHILADELPHIA METRO AREA. MILD...HIGH TEMPERATURES WELL
ABOVE NORMAL WITH HIGHS LOW/MID 60S SOUTH AND UPPER 50S NORTH.

THU NIGHT THRU FRI NIGHT...WET. THE COLD FRONT ASSD WITH THE DEEP
LOW WILL CROSS THE AREA FRI MORNING. A WEAK AREA OF LOW PRESSURE
WILL MOVE ALONG IT FRI NIGHT/EARLY SAT ONLY ADDING TO PCPN CHANCES.
TEMPERATURES WILL BE MILD THU NIGHT...BUT THEN BEGIN DROPPING BEHIND
THE FRONT FRI. LOWS WILL FALL BACK BELOW FREEZING BY SAT MORNING
OVER MUCH OF THE NRN/WRN AREAS. PCPN WILL PROBABLY END AS SNOW
ACROSS THE FAR NRN/WRN AREAS. WX GRIDS FROM EARLIER HAD THIS
TRANSITION WELL DRAWN AND ONLY MINOR CHANGES WERE MADE OVERNIGHT. A
LIGHT ACCUM IS POSSIBLE BY SAT MORNING ACROSS THE HIGHER ELEVATIONS.

SAT THRU SUN MORNING... A SHORT BREAK IN THE WET WEATHER AS HIGH
PRESSURE NOSES INTO THE AREA. COLD. HIGHS BACK A FEW DEGREES BELOW
NORMAL SAT AND 3-5 DEGREES COLDER THAN THAT SUN. HIGHS ACROSS THE
SRN AREAS MOSTLY IN THE LOW/MID 40S SAT AND CLOSE TO 40 ON SUN.
READINGS 5-7 DEGREES COLDER ACROSS THE NRN AREAS.

SUN AFTERNOON THRU TUE MORNING...ANOTHER WAVE OF LOW PRESSURE WILL
AFFECT THE AREA WITH MORE PCPN OVERSPREADING THE AREAS SUN.
TEMPERATURES INITIALLY COLD ENOUGH FOR FROZEN/FREEZING PCPN. ONCE
AGAIN SOME CHC FOR ACCUMS ACROSS THE WRN/NRN AREAS. TEMPERATURES
WARM OVERNIGHT AND ALL PCPN BACK TO RAIN BY MONDAY. QPF 0.2 TO 0.5
POSSIBLE.

TUE AFTERNOON/NIGHT...IMPROVING CONDITIONS...COLD. LOWS MOSTLY ON
THE 20S WITH TEENS FAR NORTH AND LOW 30S PHL METRO.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

TAFS EARLY THIS MORNING ARE GENERALLY VFR BEFORE A DECLINE IN
CONDITIONS AFTER SUNSET. MVFR CIGS/VSBYS ARE EXPECTED TO SPREAD
ACROSS THE AREA AFTER SUNSET, AND EVENTUALLY IFR CONDITIONS
OVERNIGHT. A PERIOD OF LIGHT RAIN AND/OR DRIZZLE IS POSSIBLE
OVERNIGHT. WINDS ARE LIGHT AND VARIABLE EARLY THIS MORNING, AND
WILL BECOME MORE EAST-SOUTHEAST DURING THE DAY, BEFORE BECOMING
LIGHT AND VARIABLE WEDNESDAY NIGHT INTO THURSDAY MORNING AGAIN.
ANY DIRECTION WEDNESDAY NIGHT INTO THURSDAY MORNING WOULD BE
MOSTLY EASTERLY.

OUTLOOK...
THU THRU SAT MORNING...LOW CIGS/VSBYS EXPECTED MUCH OF THE TIME.
PERIODS OF RAIN WHICH MAY CHANGE TO SNOW BEFORE ENDING EARLY SAT.
SAT AFTERNOON THRU SUN MORNING...MOSTLY VFR.
SUN AFTERNOON...DETERIORATING CIGS/VSBYS. PERIODS OF SNOW SLEET
AND RAIN.
-- End Changed Discussion --

&&

.MARINE...
NO HEADLINES EXPECTED ON THE WATERS FOR TODAY OR TONIGHT.

OUTLOOK...
SCA FLAG WILL PROBABLY BE NEEDED BY THU NIGHT FOR INCREASING
WINDS/SEAS...MAY BE NEEDED AS EARLY AS THU AFTERNOON (LOW CONFID).
WINDS/SEAS MAY REMAIN SCA CRITERIA INTO THE WEEKEND.

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
TIDAL DEPARTURES IN GENERAL ARE A COUPLE OF TENTHS LOWER THAN
THEY WERE YESTERDAY AT THIS SAME TIME. WITH THE HIGH TIDE CYCLE
IN PROGRESS MOST SITES ARE PEAKING BETWEEN COASTAL FLOOD ADVISORY
LEVEL TRIGGER THRESHOLDS AND THE START OF MINOR TIDAL FLOODING.
-- End Changed Discussion --

&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...O`HARA
NEAR TERM...ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...O`HARA
AVIATION...ROBERTSON/O`HARA
MARINE...ROBERTSON/O`HARA
TIDES/COASTAL FLOODING...