FXUS61 KOKX 040555
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1255 AM EST FRI DEC 4 2009

.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO TRACK THROUGH THE CANADIAN MARITIMES
TONIGHT. HIGH PRESSURE WILL BUILD IN THROUGH SUNDAY...THEN SLIDE
OFFSHORE SUNDAY NIGHT AND MONDAY. MEANWHILE...A COASTAL LOW WILL
TRACK SOUTHEAST OF LONG ISLAND SATURDAY AND SATURDAY NIGHT. A COLD
FRONT WILL CROSS THE REGION MONDAY NIGHT. HIGH PRESSURE WILL THEN
BUILD TO THE NORTH THROUGH TUESDAY NIGHT...FOLLOWED BY A COMPLEX
STORM SYSTEM DURING THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
NO CHANGES NECESSARY TO THE FORECAST. THE OVERNIGHT SHOULD FEATURE
MAINLY CLEAR SKY CONDITIONS AND SUBSIDING WINDS (EXCEPT OVER
FAR EASTERN COASTAL LOCATIONS)...AND THERE SHOULD BE DECENT
RADIATIONAL COOLING...ESPECIALLY OVER INTERIOR PORTIONS. FOLLOWED
THE COOLER OF AVAILABLE GUIDANCE AS A RESULT...WITH LOWS IN THE
30S...EXCEPT AROUND 40 TO MID 40S NEAR THE COAST AND NYC METRO.
THESE VALUES ARE 4-8 DEGREES ABOVE NORMAL.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
SOUTHWEST FLOW ALOFT...WITH NORTHERLY LOW LEVEL FLOW WILL RESULT
IN DRY CONDITIONS THROUGH SATURDAY MORNING. COLD ENOUGH ALOFT THAT
COULD SEE A FEW DIURNAL STRATO-CU DURING THE AFTERNOON...BUT
NOTHING EXCESSIVE. FOR TEMPERATURES...HIGHS TOMORROW ARE
CONSISTENT WITH MIXING DOWN FROM 850 (EXCEPT NEAR THE COAST WHERE
WATERS AROUND 50 WILL LIMIT THE TEMPERATURE RISE A BIT)...AND A
MAV/MET BLEND...WITH HIGHS ABOUT 5 DEGREES ABOVE NORMAL. DECENT
RADIATIONAL COOLING SHOULD PROMOTE LOWS NEAR NORMAL FRIDAY NIGHT
(EXCEPT A FEW DEGREES ABOVE NORMAL NEAR THE COAST).

MAIN CHALLENGE IN THE SHORT TERM IS THE COASTAL LOW FORECAST TO 
TRACK SOUTHEAST OF LONG ISLAND SATURDAY AND SATURDAY NIGHT IN 
RESPONSE TO A 500 HPA SHORTWAVE LIFTING OUT OF THE SOUTHWEST. 
THERE IS A LARGE SPREAD IN MODEL SOLUTIONS. THE GFS IS THE WEAKEST...
FARTHEST OUT TO SEA AND FASTEST. THE NAM IS THE CLOSEST TO THE COAST 
WITH THE SREF/CMC GLOBAL AND ECMWF FAIRLY CLOSELY CLUSTERED (WITH 
THE ECMWF THE FARTHEST OUT TO SEA). HAVE OPTED FOR A SREF/ECMWF 
BLEND TO HANDLE THIS SYSTEM AS IT REPRESENTS A REASONABLE SYNTHESIS 
OF THE VARIOUS SOLUTIONS. 

EXPECT PRECIPITATION TO DEVELOP FROM S TO N SATURDAY
AFTERNOON...CONTINUE SATURDAY EVENING...AND TAPER OFF AFTER
MIDNIGHT FROM W TO E. THERE IS SOME QUESTION AS TO HOW FAR N AND W
THE PRECIP SHIELD GETS...SO LIMIT LIKELY POPS TO SOUTHERN ZONES
SATURDAY NIGHT. P-TYPE IS TRICKY. ALL MODEL THERMAL FIELDS FAVOR
SNOW OVER THE NW 2/3 OF THE CWA WITH A RAIN/SNOW MIX TRANSITIONING
TO ALL SNOW OVER THE SE 1/3. HOWEVER...THE BOUNDARY LAYER IS
RATHER WARM FRO THIS TIME OF YEAR...SO WOULD EXPECT PRECIPITATION
TO START AS ALL RAIN OVER ALL BUT FAR NW AREAS SATURDAY
AFTERNOON...THEN GRADUALLY TRANSITION TO ALL SNOW BEFORE ENDING
FROM NW TO SE SATURDAY NIGHT. AT THIS TIME EXPECT AN INCH OR LESS
ACCUMULATION MAINLY ACROSS THE INTERIOR...THOUGH THE CITY AND
WESTERN LONG ISLAND COULD CHANGE OVER SOON ENOUGH BEFORE ENDING TO
SEE UP TO A SLUSHY INCH AS WELL. THE MAIN QUESTION OVER NW AREAS
IS NOT P-TYPE BUT HOW MUCH MOISTURE WILL BE AVAILABLE FOR ANY SNOW
TO FALL. ELSEWHERE THE RATE OF BOUNDARY LEVEL COOLING AND AMOUNT
OF LIQUID EQUIVALENT WILL DETERMINE HOW MUCH SNOW FALLS. WITH
QUITE A DEAL OF UNCERTAINTY...EXPECT CHANGES TO THE FORECAST AS
TIME PROGRESSES. FOR TEMPERATURES BASICALLY USED COOLER NAM
2-METER TEMPERATURES FOR HIGHS SATURDAY (REFLECTING CLOUD COVER
AND DEVELOPING PRECIPITATION)...THEN A MET/MEX BLEND LOWERED A
DEGREE OR SO SATURDAY NIGHT.

SUNDAY SHOULD END UP BEING A TYPICAL LATE FALL DAY...DRY...WITH A
LITTLE BIT OF WIND AND TEMPERATURES AROUND 40 (ABOUT 4-8 DEGREES
BELOW NORMAL).

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE BUILDS INTO THE REGION LATER SUN INTO MON...WITH DRY 
CONDITIONS PREVAILING. WARM ADVECTION AND RETURN FLOW SETS UP LATE 
MONDAY AS A WARM FRONT LIFTS NORTH OF THE REGION. SOME HINTS OF 
LIGHT PRECIP MONDAY NIGHT AND WILL KEEP SLIGHT CHANCE POPS MON NIGHT 
AND TUE. SURFACE HIGH BUILDS IN FROM THE W LATER TUE AND TUE NIGHT. 
LESS CONFIDENCE IN THE FCST ABOUNDS STARTING WED AS SOME MODEL 
UNCERTAINTY AS TO WHETHER A SECONDARY AREA OF LOW PRES DEVELOPS OFF 
HATTERAS AND ITS EVENTUAL TRACK AND STRENGTH. PRECIPITATION TYPE AND 
AMOUNT WILL BE HIGHLY DEPENDENT ON THE TRACK OF THIS SYS...AND FOR 
NOW WILL KEEP HIGH CHANCE POPS WED AND WED NIGHT. COLD SURFACE HIGH 
BUILDS IN BEGINNING THU TO CLEAR THINGS OUT FOR THE END OF THE WEEK.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
ACROSS KNYC TERMINALS...NW WINDS AT 10-15 KT SHOULD DIMINISH TO
LESS THAN 10 KT...TURNING TO A MORE WESTERLY FLOW. ACROSS THE
OTHER TERMINALS...WILL GENERALLY LOOK FOR A W-NW FLOW AT 5-10 KT.
THAT FLOW WILL BE IN PLACE THROUGH LATE AFTERNOON.

TONIGHT...BKN CIRRUS AT 20 KFT WILL OVERSPREAD THE REGION. WINDS
TURN NW AT 5-10 KT ACROSS KNYC TERMINALS...AND VRB AT 5 KT OR LESS
ELSEWHERE.

OUTLOOK 06Z SAT THROUGH TUE... 
FRI NIGHT...VFR.
SAT...SUB-VFR IN RAIN/SNOW BECOMING LIKELY DURING THE LATE
AFTERNOON AND NIGHT...ESPECIALLY AT NYC AND LONG ISLAND TERMINALS.
SUN-TUE...VFR.

&&

.MARINE...
HAVE DROPPED THE SCA FOR THE HARBOR/SOUND/BAYS AS WIND GUSTS HAVE
REMAINED BELOW 25 KT FOR THE PAST COUPLE OF HOURS AND ARE EXPECTED
TO REMAIN THAT WAY. SCA OVER THE OCEAN ZONES WILL REMAIN UNCHANGED
AS SEAS OF AT LEAST 5 FT SHOULD CONTINUE THROUGH THE NIGHT...WITH
THE TWO EASTERN OCEAN ZONES REMAINING ABOVE 5 FT INTO
FRIDAY...MAINLY DUE TO A LINGERING SE SWELL.

LIGHT WINDS FRI NIGHT...BUT SWELLS FROM THE DEPARTING COASTAL LOW
COULD KEEP SEAS UP AT SCA LEVELS E OF FIRE ISLAND INLET. NOT
CONFIDENT ENOUGH AT THIS TIME TO EXTEND SCA THAT FAR OUT IN TIME.

FOR NOW GIVEN SREF/ECMWF TRACK OF COASTAL LOW...EXPECT SCA 
CONDITIONS TO DEVELOP OVER ALL WATERS BY SAT EVENING...AND CONTINUE 
INTO SUNDAY. GUSTS TO GALE FORCE ARE POSSIBLE OVER THE COASTAL OCEAN 
WATERS SAT NIGHT AND SUNDAY AS THE COASTAL LOW DEEPENS AND PULLS 
AWAY. WINDS AND SEAS SHOULD DIMINISH LATE SUNDAY AS HIGH PRESSURE 
BEGINS TO BUILD OVER THE WATERS. 

SURFACE RIDGE CRESTS OVER THE WATERS AND SHIFTS EASTWARD...WITH 
GENERALLY LIGHT WINDS BECOMING SOUTHEASTERLY SUNDAY NIGHT 
THROUGH TUE.

&&

.HYDROLOGY...
NO SIGNIFICANT (WIDESPREAD 0.5 INCHES) PRECIPITATION IS EXPECTED
THROUGH EARLY NEXT WEEK. FOR NOW IT APPEARS THAT UP TO A FEW
TENTHS OF LIQUID EQUIVALENT IS POSSIBLE WITH THE COASTAL LOW LATE
SATURDAY AND SATURDAY NIGHT...WITH MOST OF THAT FALLING OVER
LONG ISLAND...AND SOME OF THAT IN THE FORM OF SNOW. AS A RESULT NO
HYDROLOGIC IMPACT IS EXPECTED.

&&

.TIDES/COASTAL FLOODING...
HIGH SURF ADVISORY AT SE SUFFOLK REMAINS AS IS SINCE WAVES HAVE
NOT SUBSIDED MUCH IN THE PAST COUPLE OF HOURS. SEAS OFFSHORE ARE
STILL HIGH ENOUGH TO SUPPORT SURF OF UP TO 8 FT THROUGH THIS
EVENING.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR 
     ANZ355.
     SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ350-
     353.

&&

$$
SYNOPSIS...PFM
NEAR TERM...PFM
SHORT TERM...PFM
LONG TERM...DW
AVIATION...MPS
MARINE...DW/PFM
HYDROLOGY...PFM
TIDES/COASTAL FLOODING...