FXUS61 KOKX 111450
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
950 AM EST FRI DEC 11 2009

.SYNOPSIS...
STRONG LOW PRESSURE OVER EASTERN CANADA...AND HIGH PRESSURE 
STRETCHING FROM THE PLAINS TO THE SOUTHEAST COAST...WILL CONTINUE TO 
PRODUCE WINDY CONDITIONS THROUGH TONIGHT. WINDS WILL BEGIN TO 
DIMINISH ON SATURDAY AS THE HIGH BUILDS TO THE MID ATLANTIC 
COAST...AND THEN SLIDES OFFSHORE SATURDAY NIGHT. LOW PRESSURE SLOWLY 
ORGANIZING OVER THE SOUTHEAST STATES SATURDAY NIGHT WILL MOVE INTO 
THE MID ATLANTIC REGION ON SUNDAY...AND SPREAD PRECIPITATION INTO 
THE AREA SUNDAY INTO SUNDAY NIGHT.

&&

.NEAR TERM /THROUGH TONIGHT/...
WINDS ARE THE STORY IN THE NEAR TERM WITH A STRONG PRESSURE
GRADIENT IN PLACE. VALUES WILL BE SHY OF WIND ADV CRITERIA...BUT
WITH COLD AIR IN PLACE WIND CHILL VALUES WILL BE IN THE SINGLE
DIGITS AND TEENS. MID LEVEL DISTURBANCES PASS THIS
AFTERNOON...BUT LITTLE IF ANY MOISTURE TO TAP...SO REMOVED
FLURRIES FOR ALL AREAS SAVE FOR THE TWIN FORKS REGION OF L.I.
LATEST BUFR SOUNDINGS INDICATE MORE SUN THAN CLOUDS...SO LOWERED
SKY GRIDS THROUGH TONIGHT.

FOR HIGHS...SPLIT THE DIFFERENCE BETWEEN 00Z NAM 2M TEMPS
(USUALLY TOO COLD) AND 00Z MAV MOS (USUALLY NOT COLD
ENOUGH)...WITH HIGHS ONLY IN THE UPPER 20S INLAND...AND IN THE
LOWER 30S FOR NYC METRO AND COASTAL SECTIONS.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
GUSTY W WINDS WILL SLOWLY DIMINISH TONIGHT INTO SAT AS BUILDING HIGH 
PRESSURE STARTS TO WIN THE UPPER HAND. KEPT PARTLY CLOUDY SKIES AND 
A CHANCE OF EVENING FLURRIES IN FOR ONE LAST VORT TRACKING 
ACROSS...THEN SKIES SHOULD BECOME MOSTLY CLEAR LATE TONIGHT AND 
REMAIN SO THROUGH MOST OF SAT NIGHT. CONTINUED TO UNDERCUT 00Z MAV 
MOS BY A COUPLE OF DEGREES FOR BOTH LOWS AND HIGHS...WITH TEENS 
INLAND AND LOWER 20S NYC/COASTAL SECTIONS TONIGHT...LOWER/MID 30S ON 
SAT...AND TEENS/20S AGAIN FOR SAT NIGHT AS THE HIGH BUILDS OVERHEAD. 

ATTENTION THEN TURNS TO A MID LEVEL TROUGH APPROACHING FROM THE 
WEST...WITH A BROAD LEADING AREA OF OVERRUNNING BETWEEN THE TROUGH 
AND DEPARTING HIGH PRESSURE MOVING UP INTO THE AREA ON SUNDAY...AND 
EVENTUAL DEVELOPMENT OF A WEAK SFC LOW OVER THE MID ATLANTIC COASTAL 
REGION. CLOUDS WILL START TO LOWER AND THICKEN LATE SAT NIGHT INTO 
SUN MORNING...AND IT IS POSSIBLE THAT AREAS FROM NYC SOUTH/WEST 
COULD SEE SOME LATE MORNING PRECIP. PRECIP MUCH MORE LIKELY IN THE 
AFTERNOON/EVENING...AND HAVE LEAPED UP TO LIKELY/CATEGORICAL POP AS 
THE BEST COMBO OF LOW/MID LEVEL OVERRUNNING AND MID/UPPER LEVEL 
DYNAMICS MOVE ACROSS. PRECIP WILL LIKELY BEGIN AS SNOW INLAND...AND 
RAIN OR A RAIN/SNOW MIX IN NYC AND COASTAL SECTIONS...BUT INCREASING 
LOW LEVEL WAA SHOULD QUICKLY TRANSITION PRECIP OVER TO ALL RAIN IN 
MOST PLACES. THERE IS CONCERN THAT AREAS WELL NORTH/WEST OF NYC 
COULD EXPERIENCE A PERIOD OF FREEZING RAIN...CONSIDERING WEAK SFC
FLOW AND POSSIBLE IN-SITU COLD AIR DAMMING DUE TO EVAPORATIONAL
COOLING OF PRECIP.

BY SUNDAY NIGHT...THE DEVELOPING LOW WILL BE MOVING OFF THE MID 
ATLANTIC COAST. WILL START OFF WITH CAT POP EAST AND LIKELY WEST 
SUNDAY NIGHT TO ACCOUNT FOR MODEL TIMING DIFFERENCES...THEN TAPER 
OFF TO DRY CONDITIONS BY MIDNIGHT SUNDAY NIGHT.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BRIEFLY BUILD EAST INTO THE AREA ON MONDAY. 
MODELS THEN DIFFER IN HOW NORTHERN AND SOUTHERN STREAM ENERGY IS 
HANDLED...BOTH IN TIMING AND PHASING...OR LACK THEREOF. WHERE AND 
WHEN RESULTANT LOW PRESSURE TRACKS IS THEREFORE UNCERTAIN...MAKING 
FOR A LOW CONFIDENCE FORECAST FOR TUE/WED. THE 10/12Z ECMWF AND GGEM 
FAVORED A WEAKER AND MORE PROGRESSIVE NORTHERN STREAM LOW AFFECTING 
THE AREA ON TUE...WHILE THE 10/12Z GFS TRENDED TOWARD A STRONGER 
COASTAL LOW DEVELOPING TO OUR SOUTH AND PASSING OVER OR NEAR THE 
40/70 BENCHMARK WED MORNING. DID NOT MAKE MANY CHANGES TO THIS PART 
OF THE FORECAST...AND KEPT CHANCE POP THROUGH THE PERIOD AND MIXED 
PRECIP TYPE NORTH AND WEST OF NYC...WITH RAIN CLOSER TO THE COAST.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR TODAY...ALTHO A PERIOD OF BKN040-050 POSSIBLE THIS AFTERNOON. 

HIGH CONF IN WIND FCST...WITH THE ONLY POTENTIAL BEING A FEW HIGHER 
WIND GUSTS IN THE 16-20Z TIMEFRAME DUE TO BETTER MIXING. 

TAF COMMENTS (FORECASTER INSIGHT ON TIMING, CONFIDENCE, TRENDS AND GROUND OPS)

KEWR...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED. WIND DIRECTION REMAINS LEFT OF 310...BUT MAY FLUCTUATE 
240-290 DEG TRUE. 

KEWR HOURLY WIND FORECAST
ALL WIND DIRECTIONS ARE TRUE...ADD 13 DEGREES FOR MAGNETIC
     11/12Z 26016G22KT 
     11/13Z 26016G26KT 
     11/14Z 27020G35KT 
     11/15Z 27020G35KT 
     11/16Z 27020G35KT 
     11/17Z 27020G33KT 
     11/18Z 27020G33KT 
     11/19Z 27020G35KT 
     11/20Z 27018G32KT 
     11/21Z 27017G30KT 
     11/22Z 27016G26KT 
     11/23Z 27015G20KT 

KJFK...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED.

KLGA...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED.

KTEB...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED.

KHPN...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED.

KSWF...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED

KISP...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED

KBDR...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED

KGON...FORECAST ON TRACK...NO UNSCHEDULED AMENDMENTS 
ANTICIPATED

OUTLOOK 12Z SAT THROUGH TUE... 
FRI NIGHT-SAT...VFR. WINDS DIMINISHING. 
SAT NIGHT...VFR. 
SUN-SUN NGT...SUB-VFR POSSIBLE SUN AFTERNOON/EVENING...WITH
CHANCE OF MIXED PRECIP CHANGING TO RAIN AT THE COAST...AND SNOW
CHANGING TO RAIN OR MIXED PRECIP INTERIOR. 
MON...VFR. 
TUE...SUB-VFR POSSIBLE WITH COLD FROPA.

&&

.MARINE...
THE DIFFERENCE IN PRESSURE BETWEEN A STRONG LOW OVER SOUTHEAST 
CANADA AND A HIGH OVER THE SOUTH CENTRAL U.S. WILL CONTINUE WEST 
GALES ACROSS ALL COASTAL WATERS THROUGHOUT THE DAY. A GALE WARNING 
IS IN EFFECT FOR ALL COASTAL WATERS UNTIL 6 PM.

STRONG WEST WINDS WILL LEAD TO TIDAL DEPARTURES RANGING FROM 2 TO 3 
FEET BELOW NORMAL CAUSING DOCKING PROBLEMS. A LOW WATER ADVISORY IS 
IN EFFECT UNTIL 3 PM THIS AFTERNOON AROUND TIMES OF LOW TIDE.

AS THE WEST PRESSURE GRADIENT SLOWLY WEAKENS...GALE WINDS WILL 
DECREASE BELOW WARNING LEVELS THIS EVENING ACROSS WESTERN PORTIONS 
OF THE COASTAL WATERS INCLUDING NEW YORK HARBOR AND WESTERN LONG 
ISLAND SOUND. HOWEVER...SUSTAINED WINDS OF 20 TO 25 KT WILL CONTINUE 
IN THESE AREAS AS WELL THROUGH THE DAY SATURDAY...LEADING TO AN 
EXTENDED PERIOD OF SMALL CRAFT ADVISORIES.

AS THE HIGH MOVES SOUTH OF THE REGION SATURDAY NIGHT...WINDS AND 
SEAS WILL DECREASE BELOW ADVISORY LEVELS. THIS BRIEF LULL WILL LAST 
ONLY ABOUT 24 HOURS UNTIL THE NEXT LOW MOVES EAST OF THE AREA EARLY 
MONDAY...BRINGING STRONG NW WINDS AND HIGHER SEAS ALONG WITH THE 
POSSIBILITY OF SMALL CRAFT ADVISORIES.

&&

.HYDROLOGY...
DRY WEATHER THROUGH SAT NIGHT WILL ALLOW ANY RIVERS/STREAMS TO
RECEDE. RAINFALL OF JUST OVER 1/2 INCH IS POSSIBLE FOR NYC AND
LONG ISLAND SUNDAY AFTERNOON/NIGHT...WITH 1/4 TO 1/2 INCH LIQUID
EQUIVALENT QPF FARTHER NORTH/WEST.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...LOW WATER ADVISORY UNTIL NOON EST TODAY FOR ANZ338-340-345.
     GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ335-338-345.
     LOW WATER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ330-
     335.
     GALE WARNING UNTIL 6 AM EST SATURDAY FOR ANZ330-340-350-353-
     355.

&&

$$