Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 231144
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
644 AM EST TUE DEC 23 2014

.SYNOPSIS...
A WEAK AREA OF LOW PRESSURE TRACKS JUST TO THE SOUTH AND EAST OF
LONG ISLAND THROUGH TONIGHT. A STRONGER STORM SYSTEM WILL IMPACT
THE REGION CHRISTMAS EVE THROUGH CHRISTMAS MORNING. A COLD FRONT
WILL MOVE ACROSS THE REGION CHRISTMAS DAY. HIGH PRESSURE BUILDS TO
THE SOUTH THURSDAY NIGHT THROUGH SATURDAY. A COLD FRONT APPROACHES
FROM THE NORTHWEST SATURDAY NIGHT...THEN PUSHES TO THE SOUTH
SUNDAY. THIS FRONT THEN STALLS OUT SOUTH OF THE AREA...WITH WAVES
OF LOW PRESSURE RIDING ALONG IT INTO EARLY NEXT WEEK...AS CANADIAN
HIGH PRESSURE BUILDS IN TO THE NORTH.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ISENTROPIC LIFT GRADUALLY WEAKENS THROUGH THE DAY...COUPLED WITH
500 HPA RIDGE AXIS BUILDING IN...WILL RESULT IN SPOTTY RAIN OR
DRIZZLE ACROSS THE REGION.

SOUTHERLY LOW LEVEL FLOW WILL USHER A MILD AIRMASS INTO THE
REGION WITH HIGH TEMPS RANGING FROM THE LOW TO MID 40S ACROSS THE
INTERIOR TO THE LOW 50S ALONG THE COAST.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
LOW PRES PASSES OVER MONTAUK POINT THIS EVENING. WILL KEEP CHANCE
POPS IN THE FORECAST FOR THIS EVENING AS THERE WILL BE WEAK LIFT
ALONG WITH ABUNDANT LOW LEVEL MOISTURE...AND NOT EXPECTING
WIDESPREAD RAINFALL UNTIL LATER TONIGHT.

DEEP UPPER TROUGH AND SFC LOW PRES DIGS INTO THE MIDWEST. SEVERAL
SHORTWAVES AHEAD OF THE MAIN SYSTEM WILL ENHANCE RAINFALL OVER THE
REGION BY WEDNESDAY MORNING. THE MAIN LOW TRACKS TO THE NORTH INTO
CANADA AS AN OPEN WAVE DEVELOPS OVER THE SOUTHEAST U.S. THAT WAVE
MOVES ALONG THE COAST ON CHRISTMAS EVE AND MOVES ACROSS THE REGION
WEDNESDAY NIGHT. 50-60 KT LOW LEVEL JET WILL MOVE INTO THE REGION
IN THE AFTERNOON AND AT NIGHT...AND PRECIPITABLE WATERS ACROSS THE
REGION WILL RANGE FROM 1.5-2"...WHICH IS EXCEEDINGLY HIGH FOR THIS
TIME OF YEAR. MODERATE TO HEAVY RAIN EXPECTED WEDNESDAY AFTERNOON
AND WEDNESDAY NIGHT. WITH ML MOST UNSTABLE CAPE OF 200-300 J/KG
ACROSS SOUTHERN ZONES...WILL ADD ISOLATED THUNDERSTORMS IN THE
FORECAST FOR WEDNESDAY AFTERNOON.

RAIN GRADUALLY TAPERS OFF FROM WEST TO EAST CHRISTMAS MORNING AS
COLD FRONT MOVES ACROSS THE REGION.

PRES GRADIENT TIGHTENS CHRISTMAS AFTERNOON...AND STRONG WESTERLY
WINDS WILL DEVELOP...RANGING FROM 15-20 MPH WITH 25-35 MPH GUSTS.

THE DIURNAL RANGE THROUGH THE PERIOD WILL GENERALLY RANGE FROM THE
40S AT NIGHT TO THE 50S DURING THE DAY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
DEEP LAYERED RIDGING BEGINS TO PUSH OUTER PERIPHERY OF CLOSED LOW
OVER THE CANADIAN MARITIMES TO THE NE THURSDAY NIGHT...ALLOWING
FOR CONTINUED CLEARING...ESPECIALLY OVER EASTERN ZONES. LOWS
THURSDAY NIGHT WERE BASED ON A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC
GUIDANCE WITH NAM 2-METER TEMPERATURES...WITH VALUES 5-10 DEGREES
ABOVE NORMAL.

DEEP LAYERED RIDGING BUILDS OVER THE AREA FRIDAY...WITH ITS AXIS
PASSING TO THE EAST FRIDAY NIGHT...FOLLOWED BY SW FLOW ALOFT ON
SATURDAY. SHOULD BE SUFFICIENT SUBSIDENCE WITH/IN THE VICINITY OF
THE RIDGE TO KEEP THINGS DRY WITH MINIMAL CLOUD COVER IN THIS TIME
FRAME AS A RESULT.

THE GFS IS AN OUTLIER COMPARED TO THE ECMWF/CMC/ITS ENSEMBLE MEAN
WITH HOW PROGRESSIVE IT IS WITH THE COLD FRONTAL PASSAGE FOR THE
LATTER HALF OF THE WEEKEND...AND ALSO HOW FAR OFFSHORE THE FRONT
STALLS OUT. AS A RESULT...BASED FORECAST SATURDAY NIGHT-MONDAY ON
A BLEND OF THE ECMWF/CMC/GEFS MEAN.

BASED ON THIS BLEND...SATURDAY NIGHT SHOULD BE DRY WITH NO
SIGNIFICANT FORCING PROGGED...THEN HAVE A CHANCE FOR SOME -SHRA
ACROSS SOUTHERN ZONES AND SOME -SHRA/-SHSN ACROSS NORTHERN ZONES
WITH THE COLD FRONTAL PASSAGE SUNDAY.

FOR NOW GOING WITH CHANCE POPS SUNDAY NIGHT AND SLIGHT CHANCE POPS
MONDAY TO REFLECT POTENTIAL WAVES OF LOW PRESSURE PASSING TO THE
S...WITH MAINLY SNOW EXPECTED ACROSS N ZONES...AND RAIN CHANGING
TO SNOW ACROSS S ZONES. STILL QUITE A BIT OF UNCERTAINTY ON EXACT
TIMING/STRENGTH/TRACK AND NUMBER OF THESE WAVES. FOR NOW BEST TO
CHARACTERIZE WEATHER FOR EARLY NEXT WEEK AS POTENTIALLY
UNSETTLED...WITH A BETTER CHANCE FOR SNOW THAN RAIN AT MOST
LOCATIONS...IF ANY THING FALLS AT ALL. GIVEN LARGE DEGREE OF
UNCERTAINTY...IT IS TO EARLY TO SPECULATE ON WHAT...IF ANY IMPACT
THERE WILL BE FROM THESE POTENTIALLY MULTIPLE COASTAL LOWS PASSING
TO THE S.

FOR TEMPERATURES FRIDAY-MONDAY USED A BLEND OF
MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE. TEMPERATURES WILL BE WELL ABOVE
NORMAL FRIDAY-SATURDAY NIGHT. IF ECMWF/CMC ARE CORRECT...COULD END
UP 5 TO POSSIBLY 10 DEGREES WARMER THAN CURRENTLY FORECAST - GIVEN
WELL MIXED LOW LEVELS AND 850 TEMPERATURES FORECAST OF 6 TO 8C.

SUNDAY/SUNDAY NIGHT SHOULD FEATURE TEMPERATURES SLIGHTLY ABOVE
NORMAL...THEN BELOW NORMAL TEMPERATURES ARE FORECAST FOR NOW ON
MONDAY.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
WEAK LOW PRES APPROACHES...REACHING JUST SOUTH OF LONG ISLAND
EARLY THIS EVENING.

ENE WINDS 5-15 KT...STRONGEST NEAR THE COAST.

MAINLY IFR. CHANCE MVFR THIS AFTERNOON. PERIODS OF LIGHT RAIN AND
DRIZZLE...PROBABLY BECOMING LESS FREQUENT LATE THIS AFTERNOON AND
EVENING.

     NY METRO ENHANCED AVIATION WEATHER SUPPORT...

DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)

KJFK FCSTER COMMENTS: CIGS COULD IMPROVE TO 1000-2000FT THIS
AFTERNOON.

KLGA FCSTER COMMENTS: CIGS COULD IMPROVE TO 1000-2000FT THIS
AFTERNOON.

KEWR FCSTER COMMENTS: CIGS COULD IMPROVE TO 1000-2000FT THIS
AFTERNOON.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KTEB FCSTER COMMENTS: CIGS COULD IMPROVE TO 1000-2000FT THIS
AFTERNOON.

KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

KISP FCSTER COMMENTS: CIGS COULD IMPROVE TO 1000-2000FT THIS
AFTERNOON.

.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.WED...IFR. RA. CHC +RA STARTING LATE MORNING. SE-S 10KT.     LLWS
AFTERNOON.
.WED NIGHT...IFR. RA. CHC +RA. S 15-20G20-25KT.
.THU...IMPROVING TO VFR IN THE MORNING. SHIFT W EARLY 20G30-35KT.
CHANCE OCCASIONAL GUSTS 35-40KT.
.THU NIGHT...VFR. W 15-20G30-35KT EVE...DIM 10KT BY LATE.
.FRI...VFR. W 10KT.
.SAT...VFR. SW 10KT.

&&

.MARINE...
SEAS ON THE OCEAN WILL RANGE FROM 5-7 FT TODAY AND TONIGHT. WITH
ONLY OCCASIONAL WIND GUSTS TO AROUND 25 KT EXPECTED ON THE COASTAL
OCEAN WATERS THIS MORNING...WILL MAINTAIN SMALL CRAFT ADVISORY FOR
HAZARDOUS SEAS THERE THROUGH LATE TONIGHT.

BY WEDNESDAY AFTERNOON...SCA LEVEL WIND GUSTS WILL DEVELOP ON ALL
WATERS ALONG WITH OCEAN SEAS BUILDING TO 5-7 FT AS LOW PRES MOVES
NORTH THROUGH THE WATERS.

A COLD FRONT PUSHES ACROSS THE WATERS THURSDAY MORNING. GRADIENT
TIGHTENS...AND GALE FORCE WINDS GUSTS ARE POSSIBLE ON THE WATERS
LATE THURSDAY.

GUSTS TO GALE FORCE ARE LIKELY ON THE COASTAL OCEAN WATERS AND
POSSIBLE ELSEWHERE THROUGH AT LEAST THURSDAY EVENING...AND
POSSIBLY THROUGH THE NIGHT OVER THE EASTERN COASTAL OCEAN WATERS.
WINDS AND SEAS FALL BELOW SCA LEVELS ON ALL WATERS BY FRIDAY
MORNING AND REMAIN SO THROUGH SATURDAY. SEAS COULD POSSIBLY BUILD
TO SCA LEVELS ON THE COASTAL OCEAN WATERS EAST OF MORICHES INLET
LATE SATURDAY.

&&

.HYDROLOGY...
BASIN AVG RAINFALL OF 1/2 TO 3/4 INCH EXPECTED TODAY THROUGH
TONIGHT. ANOTHER 1 TO 1 1/2 INCHES WITH LOCALLY HIGHER AMOUNTS
WEDNESDAY THROUGH THURSDAY MORNING...WITH TOTAL RAINFALL OF 1 1/2
TO 2 1/4 INCHES WITH LOCALLY HIGHER AMOUNTS. MINOR URBAN AND POOR
DRAINAGE FLOODING IS POSSIBLE.

IT SHOULD BE DRY FROM LATE THURSDAY THROUGH AT LEAST SATURDAY
EVENING.

&&

.TIDES/COASTAL FLOODING...
TIDAL DEPARTURES OF AROUND 1/2-1 FT EXPECTED VIA A STRENGTHENING E FLOW
BETWEEN DEPARTING HIGH PRESSURE AND A WEAK LOW DRIFTING UP FROM
THE SOUTH. THIS COULD BRING WATER LEVELS CLOSE TO OR JUST OVER
MINOR COASTAL FLOOD THRESHOLDS WITH THE HIGH TIDE CYCLE DURING
LATER THIS MORNING ON THE WESTERN SOUND...THE SOUTH SHORE BAYS OF
WESTERN LONG ISLAND...AND POSSIBLY IN PECONIC BAY.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM EST
     WEDNESDAY FOR ANZ350-353-355.

&&

$$

SYNOPSIS...MALOIT/MPS
NEAR TERM...MALOIT/MPS
SHORT TERM...MPS
LONG TERM...MALOIT
AVIATION...JC
MARINE...MALOIT/MPS
HYDROLOGY...MALOIT/MPS
TIDES/COASTAL FLOODING...MPS



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