FXUS61 KPHI 152036
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
336 PM EST TUE DEC 15 2009
.SYNOPSIS...
STRONG HIGH PRESSURE WILL BUILD IN FROM THE NORTH AND WEST OVER
THE NEXT SEVERAL DAYS AND LASTING INTO THE EARLY PART OF THE
WEEKEND. THE NEXT SYSTEM IS EXPECTED TO IMPACT OUR AREA ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
A COLD FRONT MOVED THROUGH THE REGION TODAY, USHERING SOME COLDER
AIR TOWARDS OUR AREA. SKIES WILL CLEAR SOME, ESPECIALLY SOUTH AND
EAST OF THE LEHIGH VALLEY, ALLOWING FOR SOME RADIATIONAL COOLING
TO OCCUR. FARTHER NORTH AND WEST WILL EXPERIENCE SOME CLOUDIER
SKIES. THE COLD AIR MOVING OVER THE WARM LAKES WILL CREATE LAKE
EFFECT SNOW SHOWERS AND IN CONJUNCTION WITH A VORT MAX MOVING
THROUGH, THESE SNOW SHOWERS MAY REACH OUR NORTHERN AREAS
OVERNIGHT.
LOW TEMPERATURES WILL BE IN THE UPPER 20S TO LOWER 30S ACROSS MOST
OF THE AREA WITH SOME LOW TO MID 20S IN THE HIGHER TERRAIN.
WINDS WILL BE A BIT BRISK WHICH WILL HELP TO MAKE IT FEEL COLDER
THAN IT IS OUTSIDE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
SOME LINGERING SNOW SHOWERS MAY CONTINUE IN THE NORTHERNMOST AREAS
INTO WEDNESDAY MORNING BUT SHOULD BECOME MORE ISOLATED BEFORE
TAPERING OFF THROUGH THE DAY. MORE SNOW SHOWERS ARE POSSIBLE ON
WEDNESDAY NIGHT IN THESE SAME AREAS AS COLDER AIR MAKE SIT WAY INTO
THE REGION. MAXIMUM TEMPERATURES IN THESE AREAS ARE EXPECTED TO
REACH INTO THE UPPER 20S FOR THE WEDNESDAY THROUGH FRIDAY TIME
PERIOD. OVERNIGHT TEMPERATURES INTO THE TEENS CAN BE EXPECTED AS
WELL.
ELSEWHERE, DRY AND COOLING CONDITIONS CAN BE EXPECTED THROUGH THE
COURSE OF THE WEEK. WEDNESDAY WILL REACH NEAR 40 FOR A HIGH AND THEN
EACH DAY WILL BE A FEW DEGREES COOLER THAN THE NEXT AS HIGH PRESSURE
BUILDS IN FROM THE NORTH AND WEST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS CONTINUE TO DIFFER AS TO HOW THEY HANDLE THE ROTATING
UPPER LOW TO OUR NORTH ALONG WITH THE ASSOCIATED SHARPENING TROUGH.
AT THE SURFACE, ALL MODELS DEVELOP A LOW ALONG THE SE COAST AND
HEAD IT NE. MOST OF THE MODELS KEEP IT FAR ENOUGH S AND E OF OUR
AREA SO THAT IT JUST BRUSHES OUR SE SECTIONS. THE OUTLIER AT THIS
TIME IS THE ECMWF WHICH SHARPENS THE TROUGH AND DEVELOPS AN INTENSE
EAST COAST STORM. IT IS ALSO MUCH FASTER THAN THE REST OF THE MODELS
AND WOULD HAVE THE BIGGEST IMPACT LATE SATURDAY AND SATURDAY NIGHT
RATHER THAN LATE SATURDAY NIGHT AND SUNDAY. FOR NOW WE WILL GO WITH
THE MAJORITY AND BRING INCREASING CLOUDINESS IN LATE SATURDAY INTO
SATURDAY NIGHT AND CALL FOR A CHANCE OF SNOW INLAND AND RAIN OR SNOW
ALONG THE COAST LATE SATURDAY NIGHT AND SUNDAY. ONCE THE LOW MOVES
OFF TO THE NE, HIGH PRESSURE WILL BRING ANOTHER BATCH OF COLD AIR
INTO OUR AREA FOR THE BEGINNING OF NEXT WEEK.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE SOMEWHAT POORLY DEFINED COLD FRONT APPEARS TO BE MOVING OFF THE
MID-ATLANTIC COAST AND NW WINDS BEHIND THE FRONT HAVE CLEARED OUT
THE LOW CLOUDS AND FOG. AN OVERALL CLEARING TREND IS EXPECTED TO
CONTINUE THROUGH LATE AFTERNOON AND INTO THE EVENING AS DRIER AIR
FILTERS INTO THE LOWER AND MID LEVELS OF THE ATMOSPHERE. ANY
GUSTINESS THIS AFTERNOON SHOULD DIE DOWN AFTER SUNSET AS THE SURFACE
COOLS AND THE BOUNDARY LAYER PARTIALLY DE-COUPLES.
NW LOW-LEVEL FLOW WILL CONTINUE THROUGH THE DAY WEDNESDAY. 25 TO 30
KT FCST WINDS AT 850 MB COULD MIX DOWN AND CAUSE GUSTINESS AT THE
SURFACE. THE NW FLOW WILL ALSO CARRY SOME MOISTURE FROM THE LOWER
GRTLKS RESULTING IN SOME STREAMERS OF SCT/BKN LOW CLDS...BKN MORE
LIKELY AT RDG/ABE.
OUTLOOK...
GENERALLY VFR CONDITIONS ARE FORECAST FOR MUCH OF THE REST OF THIS
WEEK. WINDS WILL CONTINUE FROM THE NW AND WILL BE GUSTY AT TIMES.
&&
.MARINE...
NW WINDS ARE STARTING TO PICK UP OVER THE FORECAST WATERS THIS
AFTERNOON. WE EXPECT THIS TREND TO CONTINUE INTO THE EVENING WITH
SOME 25 KT TO POSSIBLY 30 KT GUSTS DEVELOPING OVERNIGHT AS COLDER
AIR MOVES OVER THE WARMER WATER. THE CURRENT SCA FOR ALL FORECAST
WATERS REMAINS AS IS. WINDS COULD DIE DOWN SMWNT ON WED BUT THEN
PICK UP AGAIN WED NIGHT. ALSO THE SCA COULD END UP BEING EXTENDED
INTO THU IF NW WINDS PERSIST AS FCST ATTM.
WITH THE PERSISTENT NW FLOW THE SEAS WILL BUILD OVER THE COASTAL
WATERS AND OVER DELAWARE BAY...BUT WILL BE LIMITED BY THE RELATIVELY
SHORT FETCH. BUOY 44009 CLIMO SUGGESTS WAVE COULD REACH 5 TO 6 FT AT
TIMES NEAR THE OUTER EDGE OF COASTAL ZONE...ABOUT 20 NM OUT. HIGHER
WAVES ARE ALSO LIKELY OVER LOWER DEL BAY WITH NW FLOW ORIENTED DOWN
THE BAY.
WINDS AND SEAS WILL DECREASE BY LATE WEEK AS HIGH PRESSURE BUILDS
OVER THE WATERS. LOW PRES IS FCST TO DEVELOP BY LATE SAT SOUTH OF
CAPE HAT AND MOVE NE FROM THERE. THE GFS IS WEAKER AND FURTHER S
WITH LITTLE EFFECT ON THE NJ/DE COASTS...BUT THE ECMWF IS STRONGER
AND FURTHER N RESULTING IN A PERIOD OF NE WINDS AND PRECIP FOR SAT
NIGHT INTO SUN MORN. OUR CURRENT FCST TENDS TO FAVOR THE STRONGER
ECMWF. NW FLOW BEHIND THE LOW PRES WILL DOMINATE FOR EARLY NEXT
WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...MEOLA
SHORT TERM...MEOLA
LONG TERM...RPW
AVIATION...AMC
MARINE...AMC
