Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

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000
FXUS61 KPHI 191049
AFDPHI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
549 AM EST WED NOV 19 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN TO THE REGION TODAY...FOLLOWED BY A COLD
FRONTAL PASSAGE ON THURSDAY. BEHIND THIS FRONT, A MUCH STRONGER HIGH
PRESSURE SYSTEM WILL MOVE IN FROM THE WEST ON FRIDAY, THEN REMAIN
OVER THE AREA ON SATURDAY BEFORE MOVING OFFSHORE ON SUNDAY.
MEANWHILE, LOW PRESSURE WILL DEVELOP ACROSS THE SOUTHERN PLAINS
AND MOVE TO NEAR THE GREAT LAKES. THE LOW WILL INTENSIFY AS IT MOVES
EASTWARD EARLY NEXT WEEK, BRINGING A COLD FRONT THROUGH THE REGION
MONDAY NIGHT OR TUESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE UPPER TROUGH THAT HAS LEFT A LARGE PART OF THE UNITED STATES IN
AN DEEP FREEZE WILL REMAIN OVERHEAD TODAY, ALTHOUGH IT DOES FLATTEN
OUT OVER THE EAST AS SHORTWAVE ENERGY MOVES OFF THE NEW ENGLAND
COAST AHEAD OF THE LARGE SCALE TROUGH. SOUTHWEST FLOW DEVELOPING
THIS AFTERNOON WILL ADVECT WARMER AIR ALOFT INTO THE REGION. THE WAA
IS FORECAST TO BE MOST NOTABLE IN THE 4-8 KFT LAYER ABOVE THE
SURFACE, WHICH WOULD BE ABOVE THE MIXED LAYER AND THUS NOT HELP MUCH
TO MODERATE SURFACE TEMPS. MAX TEMPS TODAY ARE GENERALLY IN THE LOW
TO MID 30S AND ARE SIMILAR TO YESTERDAY AFTERNOON.

THE PRESSURE GRADIENT WILL WEAKEN OVER THE MID-ATLANTIC REGION TODAY
AS THE 1033 MB SURFACE HIGH THAT IS CURRENTLY OVER THE NORTHERN GULF
COAST STATES RIDGES DOWNSTREAM TOWARD OUR AREA WHILE LOW PRESSURE
OVER NORTHEASTERN CANADA LIFTS FARTHER AWAY FROM OUR AREA. THE WINDS
WILL BE LIGHTER TODAY COMPARED TO YESTERDAY. NONETHELESS, A 10-15
MPH WIND IN THIS ARCTIC AIRMASS WILL RESULT IN WIND CHILLS THAT ARE
ABOUT 10 DEGREES LOWER THAN THE AMBIENT TEMPERATURE.

TODAY WILL START OFF SUNNY BEFORE MID AND HI CLOUDS STREAM IN FROM
THE WEST DURING THE MID TO LATE AFTERNOON.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
A NORTHERN STREAM SHORTWAVE TROUGH DIVING SOUTHEASTWARD FROM
MANITOBA WILL LEAD TO THE DEVELOPMENT OF A GREAT LAKES LOW TONIGHT.
THE FLOW DOWNSTREAM OF THIS SYSTEM WILL BACK FURTHER OUT OF THE
SOUTHWEST ALOFT AND THE SOUTH AT THE SURFACE. 00Z NAM/GFS FORECAST
SOUNDINGS BOTH INDICATE A 50 KT SOUTHWESTERLY LOW-LEVEL JET
DEVELOPING OVERHEAD TOWARD MIDNIGHT.

AFTER THE AIRMASS INITIALLY COOLS TOWARD SUNSET, TEMPS ARE FORECAST
TO REMAIN STEADY OR EVEN WARM LATER IN THE EVENING AND OVERNIGHT IN
RESPONSE TO WAA OCCURRING WITHIN THE BOUNDARY LAYER AND INCREASING
MID CLOUDS. LOWS RANGING FROM AROUND 20F IN THE POCONOS TO AROUND
30F ALONG THE COAST ARE FORECAST TO OCCUR IN THE EVENING FOR MOST
LOCATIONS.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
ON THU, LOW PRES WILL BE LOCATED OVER ERN CAN HE LOW WILL MOVE
EWD, BRINGING A CDFNT THU THE REGION. THE FRONT IS WEAK AND HAS
LITTLE MOISTURE TO WORK WITH, SO WE ARE KEEPING THINGS DRY.

BEHIND THE FRONT, A LARGE AREA OF HIGH PRES OVER THE MIDSECTION OF
THE COUNTRY WILL WORK ITS WAY EWD. THIS WILL ALSO BRING A PATN
CHANGE TO THE AREA, AS THE TROF THAT BROUGHT THE UNSEASONABLY COLD
WX TO THE AREA MOVES OFFSHORE AND HGTS RISE AND THE TROF IS
REPLACED BY A RIDGE BY THE WEEKEND.

THE HIGH WILL BE OVERHEAD ON SAT AND MOVE OFFSHORE ON MON. EXPECT
SEVERAL WARM DAYS WITH WARMING TEMPS. AS THE SWLY FLOW INCREASES
WITH THE HIGH MOVG OFFSHORE, THERE WILL BE A MARKED RISE IN TEMPS
FROM SAT TO SUN AND FURTHERMORE INTO MON.

AS THE HIGH MOVES OVER THE ERN CONUS, AN AREA OF LOW PRES WILL
TAKE SHAPE OVER THE SRN PLAINS ON SAT. THIS LOW WILL MOVE NNEWD TO
NR ST. LOUIS BY 23/18Z AND NR THE GRTLKS BY 24/00Z. THE POSN OF
THE LOW IN THE GFS AND ECMWF ARE SIMILAR BY 24/00Z THOUGH THE
ECMWF IS ABOUT 8 MB STRONGER.

BY SUN MRNG, THE GFS AND CMC HAVE A WMFNT TO THE N OF THE PA/NY
BRDR AND KEEP PRECIP N OF THE REGION, WHILE THE ECMWF IS A BIT
FURTHER S, WITH SOME PRECIP OVER NRN AND WRN AREAS. IF PRECIP GETS
AN EARLY ENOUGH START, IT COULD START OFF AS THE WINTRY VARIETY
WITH TEMPS AOB FREEZING. HOWEVER, CONFIDENCE IS LOW ON ONSET TIME
THIS FAR OUT. WITH SUCH A STRONG LOW DEVELOPING, AND PULLING IN
GULF MOISTURE, A SLOWER AND WARMER SYS IS GENERALLY EXPECTED, SO
THIS WOULD BE MORE SUPPORTIVE OF THE GFS/CMC, BUT FOR NOW WILL
JUST KEEP SOME LOW POPS.

THE GUID THEN KEEPS MOST OF THE DAYTIME HOURS OF SUN DRY IN THE
WARM SECTOR BEFORE THE LOW REALLY STARTS TO WIND UP CLOSER TO SUN
EVE NR THE GRTLKS AND THE CDFNT APPROACHED FROM THE W.

THE HIGHEST POPS LOOK TO BE SUN EVE/NIGHT WITH A FIRST CDFT. THERE
CUD BE SOME HVY RAIN AS WELL. TEMPS WILL BE WARM ENOUGH EVERYWHERE
THAT THE BULK OF THE PRECIP WILL BE PLAIN RAIN. BEHIND THIS FRONT,
THERE COULD BE SOME LINGERING RAIN INTO MON BEFORE A SECONDARY CFP
OCCURS MON NIGHT ORE EARLY TUE AND ENDS THE RAIN CHCS AND RE-
ESTABLISHES A TROF OVER THE CONUS. THERE ARE STILL SOME DIFFS TO
BE IRONED OUT IN THE MDLS BUT THERE ARE 4 TO 5 DAYS FOR THIS TO
OCCUR.

TEMPS WILL WARM FOR THU, THEN DROP A BIT FRI AND SAT BEHIND THE
FIRST CFP. THEN THEY WILL SOAR SUN AND MON IN STRONG SWLY FLOW.
THERE COULD BE CLOSE TO A 30 DEGREE TEMPERATURE RISE BETWEEN FRI
AND MON!

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.

VFR TODAY AND TONIGHT.

THE GUSTY NW WINDS CONTINUE TO DIMINISH OVERNIGHT. A TEMPO GROUP WAS
INCLUDED IN THE 06Z TAFS TO CAPTURE OCCASIONAL GUSTS TO NEAR 20 KT
THRU DAYBREAK FOR THE PHILLY AND SOUTHERN NJ TERMINALS. WLY WINDS
BECOME SWLY THIS AFTN AND EVEN SLY AROUND SUNSET.

BY 06Z THURSDAY, SW WINDS ALOFT STRENGTHEN TO ABOUT 50 KT AT 3000 FT
ABOVE THE SURFACE. WHILE NOTABLE, MODEL OUTPUT DOES NOT INDICATE IT
QUITE MEETING LLWS CRITERIA.

OUTLOOK...

THU...VFR. CFP THU AFTN MAY RESULT IN WLY WIND GUSTS 25-30 KTS.
MDT CONFIDENCE.

FRI THRU SAT...VFR. HIGH PRESSURE. HIGH CONFIDENCE.

SUN...LOW PRES APPROACHES FROM THE W WHICH WILL BRING RAIN TO THE
AREA. MVFR POSSIBLE IN LOW CIGS AND VSBYS WITH RAIN...ESPECIALLY
IN THE LATER PART OF THE DAY. LOW CONFIDENCE ON TIMING.

&&

.MARINE...
630 AM UPDATE...GALE WARNING WAS CANCELLED AND REPLACED BY A
SMALL CRAFT ADVISORY AS WINDS GRADUALLY WEAKEN. THE SMALL CRAFT
ADVISORY IS IN EFFECT THRU 11 AM THIS MORNING.

PREVIOUS DISCUSSION...AS OF 3 AM, WESTERLY WINDS ARE STILL
GUSTING AROUND 35 KT AT NEARBY BUOYS 44025/65 AND AT THE CAPE MAY
WX FLOW STATION. WINDS ARE FORECAST TO WEAKEN OVER THE NEXT FEW
HOURS, SO THE CURRENT 6 AM GALE WARNING EXPIRATION TIME SHOULD
STILL WORK. A SCA WILL BE ISSUED TO COVER THE EARLY AND MID
MORNING. NO HEADLINES ARE EXPECTED FOR THIS AFTERNOON.

WINDS BACK OUT OF THE SOUTHWEST AND THEN STRENGTHEN TONIGHT. ONCE
THE MORNING HEADLINES EXPIRE, A SCA WILL LIKELY BE ISSUED FOR
TONIGHT FOR THE COASTAL ATLANTIC WATERS AND AT LEAST THE LOWER
DELAWARE BAY (BOTH WINDS AND SEAS). THERE IS ALSO CONCERN FOR GALES
TONIGHT OVER THE COASTAL ATLANTIC WATERS. SOUTHWEST FLOW ARE NOT
TYPICALLY ASSOCIATED WITH FAVORABLE MIXING SETUP. HOWEVER, THE
MODERATING AIRMASS ABOVE THE RELATIVELY WARM OCEAN MAY STILL BE COLD
ENOUGH TO SUPPORT MIXING OF 35 KT WINDS ALOFT DOWN TO THE SURFACE.
WILL LET THE DAY SHIFT ANALYZE THE NEWEST SET OF GUIDANCE BEFORE
DECIDING WHICH MARINE HEADLINE IS BEST SUITED FOR TONIGHT.

OUTLOOK...

THU AND FRI...SCA LIKELY IN INCREASING SW FLOW AHEAD OF A CFP AND
AGAIN BEHIND THE FRONT IN W-NW WINDS...GENERALLY 25-30 KT. ALSO,
CANNOT RULE OUT A PERIOD OF GALES LATE ON THU INTO EARLY FRI.

FRIDAY NIGHT THROUGH SUNDAY...SUB-SCA CONDITIONS ARE EXPECTED.

&&

.CLIMATE...
BELOW IS A LISTING OF RECORD LOW TEMPERATURES AND THE YEAR OF
OCCURRENCE FOR TODAY, NOVEMBER 19 FOR OUR EIGHT CLIMATE SITES.

RECORD LOWS FOR THIS MORNING:

ACY 18  1936
PHL 20  1936
ILG 15  1936
ABE 11  1924
TTN 17  1936
GED 20  1959
RDG 18  1936
MPO 10  1933

ADDITIONALLY, NEAR RECORD LOW MAX TEMPERATURES ARE FORECAST FOR
TODAY.

11/19 RECORD LOW MAX TEMPS:   11/19 FORECAST MAX TEMPS:

ACY 35  1951                   ACY  35
PHL 35  1951                   PHL  33
ILG 34  1951                   ILG  34
ABE 32  1951                   ABE  30
GED 38  2008                   GED  35
MPO 24  1951                   MPO  24



&&

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR ANZ430-
     431-450>455.

&&

$$
SYNOPSIS...NIERENBERG
NEAR TERM...KLEIN
SHORT TERM...KLEIN
LONG TERM...NIERENBERG
AVIATION...KLEIN/NIERENBERG
MARINE...KLEIN/NIERENBERG
CLIMATE...KLEIN






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