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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPHI 011800
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
100 PM EST SUN DEC 1 2013

.SYNOPSIS...
STRONG HIGH PRESSURE IS CENTERED NEAR NEWFOUNDLAND TODAY. LOW
PRESSURE FORMING OFF THE SOUTH ATLANTIC COAST LATE TONIGHT WILL
SLOWLY INTENSIFY AS IT MOVES OFFSHORE MONDAY INTO TUESDAY. STRONG
LOW PRESSURE IN THE UPPER GREAT LAKES WEDNESDAY MOVES INTO SOUTH
CENTRAL CANADA THURSDAY SENDING A COLD FRONT EASTWARD TO THE EAST
COAST. AREAS OF LOW PRESSURE SHOULD FORM ON THE FRONT AND MOVE
NORTHEASTWARD THURSDAY NIGHT INTO THE WEEKEND AS A PIECE COLDER
HIGH PRESSURE SPREADS EASTWARD INTO THE GREAT LAKES AND NORTHEAST.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MORNING VIS STLT LOOP SHOWS ABUNDANT SUNSHINE OVER MOST OF THE
FCST AREA...EXCEPT FOR THE POCONOS AND FAR NW NJ. AS A RESULT THE
TEMPS ARE RUNNING A FEW DEGS WARMER THAN EXPECTED...SO HOURLY
TEMPS WERE ADJUSTED AND FCST MAX TEMPS WERE BUMPED UP A COUPLE OF
DEGREES. THERE IS A MID CLOUD DECK APPROACHING FROM THE WEST AND
THIS SHOULD OVERSPREAD THE AREA FROM EARLY THROUGH MID AFTN.

OTRW...WE REMAIN UNDER GENLY ZONAL FLOW ALOFT WITH A WEAK SFC PRES
PATN AND ASSOCD LIGHT SFC WINDS. ASIDE FROM SKY COVER AND TEMPS,
NO OTHER CHANGES WERE MADE TO THE CURRENT FCST.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
A WEAKENING COLD FRONT WILL MOVE INTO THE AREA TONIGHT BUT IT
DOESN`T LOOK LIKE IT REALLY GETS HERE. A SHORTWAVE WILL MOVE
ACROSS TO THE NORTH OF OUR AREA TONIGHT AND THAT WILL BRING IN
SOME EXTRA CLOUDS, ESPECIALLY ACROSS THE NORTHERN AREAS OVERNIGHT.

WITH PLENTY OF CLOUDS IN THE AREA TONIGHT, TEMPERATURES WILL REMAIN
SLIGHTLY MORE MODERATE. EXPECT LOWS TO BE INT HE UPPER 20S TO LOWER
30S THROUGH MUCH OF THE REGION. THE URBAN AREAS MAY REMAIN CLOSER TO
THE MID 30S OVERNIGHT.

&&

.LONG TERM /MONDAY THROUGH SUNDAY/...
500 MB: A NEGATIVE TILT SHORT WAVE DEVELOPS NORTHEASTWARD FROM THE
CENTRAL APPALACHIANS MONDAY REACHING NOVA SCOTIA TUESDAY NIGHT.
RIDGING FOLLOWS OVER THE SOUTHEAST UNITED STATES WEDNESDAY INTO
FRIDAY WHILE A POSITIVE TILT COLD TROUGH DEVELOPS FROM CANADA BACK
TO THE CENTRAL ROCKIES. THAT TROUGH ATTEMPTS TO SHIFT EASTWARD A
BIT NEXT WEEKEND WITH A STRONG SURFACE FRONT SETTING UP A POTENTIALLY
UNSETTLED BATTLE ZONE BETWEEN THE WARM AIRMASS IN THE SOUTHEAST
AND THE COLD OVER THE PLAINS STATES.

TEMPERATURES: CALENDAR DAY AVERAGES SHOULD BE ABOVE NORMAL MONDAY
THROUGH THURSDAY...POSSIBLY 5 OR 10 DEGREES ABOVE NORMAL WEDNESDAY
AND THURSDAY. THEREAFTER FRIDAY THROUGH NEXT WEEKEND LOOKS LIKEN IT
SHOULD COOL TO NEAR NORMAL....ESPECIALLY NEXT WEEKEND.

FORECAST BASIS:  MONDAY THROUGH TUESDAY IS BASICALLY A 50 50 BLENDED
COMPROMISE BETWEEN THE 00Z/1 GFS/NAM MOS...UNLESS OTHERWISE NOTED
IN THE DAILIES SECTION. WEDNESDAY THROUGH SATURDAY IS BASED ON THE
0443Z/1 WPC GRID...BLENDED AT LEAST 50 50 COLDER WITH THE NEW
00Z/1 GFS MOS FRIDAY AND SATURDAY. THE 00Z/1 ECMWF 2M TEMPS AND
MASS FIELDS HELPED MODIFY THE FORECAST. THE 30/21Z SREF 3HR POPS
FOR .01 WERE CONSIDERED MONDAY AND TUESDAY. THE 00Z/1 GEFS PROBS
FOR .05 IN 6 HRS WERE CONSIDERED FOR THE WEDNESDAY THROUGH
SATURDAY PORTION AND A PRIMARY REASON WHY I RESTRAINED ISSUING
LIKELY POPS FOR THURSDAY NIGHT-FRIDAY.

THE DAILIES...

MONDAY...QUIET...STILL UNDER THE SOUTHWEST EXTENSION FROM THE STRONG
HIGH NEAR NEWFOUNDLAND.  FAVORED THE WARMER NAM BL AND ASSOCIATED
MAX TEMPS. WE HAVE A SMALL CHC OF A SHOWER IN THE POCONOS NEAR A
DECAYING APPROACHING COOL FRONT. ALSO...HAVE A CHANCE OF SHOWERS
ALONG THE FAR SE EDGE OF OUR FCST AREA MON AFTN/EVENING IN
RESPONSE TO THE LOW PRESSURE DEVELOPMENT TO THE SOUTH.

TUESDAY...LOW PRESSURE DEVELOPING NORTHEASTWARD OFFSHORE COMBINES
WITH ITS GENERATING NEGATIVE TILT SHORT WAVE TO THREATEN A PERIOD OF
RAIN FOR THE COAST...MAINLY PRIOR TO DAWN TUESDAY. THE PRESSURE
GRADIENT WILL TIGHTEN A BIT ALONG THE COAST WITH A NORTHERLY WIND
OCCURRING. FAVORED THE WARMER MAX TEMPS OF THE NAM...ESPECIALLY
SINCE MOST OF THE AREA IS A NEAR MISS ON ANY RAIN WHICH SHOULD
ALLOW GREATER WARMING DESPITE NORTHERLY FLOW. THIS NORTH WIND
DOES NOT APPEAR TO BE DRAWING ANY COLD AIR SOUTHWARD SINCE A NEW
COLD AIR RESOURCE HAS NOT BEEN ESTABLISHED TO OUR NORTH. ABOVE
NORMAL DAYTIME TEMPS.

WEDNESDAY...WEAK HIGH PRESSURE IN THE SOUTHEAST UNITED STATES
DOMINATES OUR WEATHER WITH I THINK IT SHOULD BE A QUIET DAY WITH
ABOVE NORMAL TEMPERATURES. SHOWERS HAVE BEEN ADDED TO THE FCST
ACROSS THE NORTH TWO THIRDS OF THE AREA BUT ITS A SMALL CHANCE AND
ASSOCIATED WITH APPROACH OF A COLD FRONT FROM THE WEST.

THURSDAY...MODEL DISAGREEMENT HERE. TIMING A CFP AND CHANCE OF
RAIN IS THE PRIMARY ISSUE. IT LOOKS TO BE A VERY MILD DAY.

FRIDAY...MODEL DISAGREEMENT IS THE ONLY REASON I HELD BACK ON
LIKELY POPS. NEVERTHELESS.. I THINK WE HAVE A RAIN EVENT AT THE
LEAST... AND POSSIBLY WINTRY ELEMENTS IN PTNS OF E CENTRAL AND NE
PA AS WELL AS NNJ. DETAILS TO BE DETERMINED AND CONFIDENCE IN THE
CURRENT FCST TEMPS AND POPS IS BELOW AVG. A COLD FRONT SHOULD HAVE
BECOME NEARLY STATIONARY TO OUR SOUTH AND A DISTURBANCES IN THE JET
STREAM SHOULD DEVELOP OVERRUNNING. EVER COLDER TEMPERATURES
DEVELOPING NEAR AND NORTH OF 40 DEGREES LATITUDE. VERTICAL THERMAL
MOISTURE PROFILES...OFFER POTENTIALLY WINTRY MESS SCENARIOS...
PRESUMING ITS PRECIPITATING.

NEXT WEEKEND...DETAILS TO BE DETERMINED BUT A PORTION OF THE WEEKEND
MAY BE UNSETTLED WITH EVEN COLDER THERMAL PROFILES. DIDNT SPEND MUCH
TIME DISCUSSING THIS SINCE CONFIDENCE ON HOW THIS POSITIVE TILT
TROUGH PATTERN EVOLVES IS BELOW AVERAGE AND THERE ARE MULTIPLE
SCENARIOS.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.

THE LEADING EDGE OF A MID-LVL CLOUD DECK IS ADVANCING EWD AT
AROUND 25 KT ACROSS ERN PA. IT HAS ALREADY REACHED ABE/RDG AND
SHOULD REACH PHL AND LOWER DELAWARE VLY SHORTLY AFTER 18Z. TIMING
FOR ACY/MIV IS NOT CERTAIN, BUT OVC080 OR BKN080 CIG WAS INCLUDED
IN THE FIRST TIME PERIOD FOR ALL 18Z TAF SITES.

VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE TAF PERIOD.

A WEAK BOUNDARY WILL MOVE THROUGH THE REGION LATER IN THE DAY AND
CEILINGS WILL LOWER INTO THE 7000-10000 FT RANGE. CEILINGS WILL
BE LOWER ACROSS THE NORTHWESTERN TERMINALS AS A MID LEVEL
DISTURBANCE MOVES THROUGH JUST TO THE NORTH TONIGHT.

WINDS ARE LIGHT AND VARIABLE AND WILL CONTINUE TO BE LIGHT AND
VARIABLE THROUGH THE MAJORITY OF THE TAF PERIOD. WINDS WILL BACK
FROM THE NORTHWEST TO THE SOUTHWEST WITH WIND SPEEDS AROUND 5-6
KNOTS THIS AFTERNOON BEFORE SUBSIDING.


OUTLOOK...
MONDAY...VFR. SCT-BKN CLOUDS AOA 5000 FT. LIGHT WIND. CONFIDENCE:
AVERAGE.

MONDAY NIGHT...VFR. SCT-BKN CLOUDS AOA 5000 FT MAY BECOME BRIEF MVFR
CONDS ALONG THE COAST IN A PERIOD OF RAIN? WIND BECOMING NORTH 5
TO 15 KT. CONFIDENCE ON ANY OCCURRENCE OF MVFR CONDS IN RAIN IS
BELOW AVG.

TUESDAY...SCT-BKN CLOUDS AOA 3500 FT. N WIND. CONFIDENCE: AVERAGE.

WEDNESDAY MORNING...PROBABLY VFR.  LIGHT WIND. CONFIDENCE: AVERAGE

LATE WEDNESDAY AND THURSDAY...A PERIOD OF MVFR CONDS IN SHOWERS IS
POSSIBLE ASSOCIATED WITH COLD FRONTAL PASSAGE. SW WIND SHIFT NW.
CONFIDENCE: AVERAGE.
-- End Changed Discussion --

&&

.MARINE...
SUB ADVISORY CONDITIONS ARE EXPECTED FOR SUNDAY.

HIGH PRESSURE WILL SLIDE ACROSS TO THE SOUTH OF THE AREA TONIGHT AS
A WEAK FRONTAL BOUNDARY APPROACHES THE REGION. WINDS WILL REMAIN
FAIRLY LIGHT ON THE OCEAN WATERS. WINDS WILL BE OUT OF A WEST TO
NORTHWEST DIRECTION WITH WIND SPEEDS AROUND 5 TO 10 KNOTS. SEAS
WILL REMAIN AROUND 1 TO 2 FEET ON THE BAY AND 2 TO 3 FEET ON THE
OCEAN.


OUTLOOK...
MONDAY-TUESDAY...A SCA MAY BE NEEDED MONDAY NIGHT OR TUESDAY...
MAINLY FOR THE ATLANTIC COASTAL WATERS... ASSOCIATED WITH
DEVELOPING AND NORTHEASTWARD MOVING OFFSHORE LOW PRESSURE SYSTEM.
CONFIDENCE FOR AN SCA ISSUANCE: BELOW AVERAGE.

WEDNESDAY-THURSDAY...FOR NOW NO HEADLINE ANTICIPATED. A COLD FRONTAL
PASSAGE IS EXPECTED THURSDAY WITH A WIND SHIFT FROM SW TO NW.
CONFIDENCE: AVERAGE

&&

.CLIMATE...
CLMS RAN AT 444 AM. NOVEMBER CLIMATE STATS ARE OUT. GENERALLY A
COLDER THAN NORMAL NOV BY 2 TO 3 DEGS (PHL WAS -2.1).

&&

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

&&

$$
SYNOPSIS...DRAG
NEAR TERM...AMC/MEOLA
SHORT TERM...MEOLA
LONG TERM...DRAG
AVIATION...AMC/DRAG/MEOLA
MARINE...DRAG/MEOLA
CLIMATE...