Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 311758
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1258 PM EST SAT JAN 31 2015

.SYNOPSIS...
DEEP LOW PRESSURE SLOWLY MOVES NORTHEAST AS HIGH PRESSURE BUILDS
IN FROM THE WEST. A COLD FRONT WILL MOVE THROUGH ON SUNDAY. LOW
PRESSURE APPROACHES FROM THE OHIO VALLEY AND PASSES SOUTH OF LONG
ISLAND MONDAY. THE LOW TRACKS WELL TO THE EAST MONDAY NIGHT WITH
HIGH PRESSURE BUILDING IN ITS PLACE. THE HIGH MOVES ACROSS TUESDAY
AND OFFSHORE TUESDAY NIGHT. A COLD FRONT MOVES ACROSS MIDWEEK WITH
ANOTHER LOW PASSING WELL OFFSHORE LATE IN THE WEEK. BY THAT TIME
FRAME...HIGH PRESSURE WILL BE CENTERED WEST OF THE REGION.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLEAR SKIES...GUSTY WINDS AND COLD TEMPERATURES ARE EXPECTED
TODAY.

WIND AND WINDCHILL ADVISORIES HAVE BEEN CANCELLED/EXPIRED BASED
ON SUBSIDING BOUNDARY LAYER WINDS AND SLOWLY MODERATING TEMPS
THROUGH THE LATE MORNING/EARLY AFTERNOON. NORTHWEST WIND GUSTS OF
35 TO 40 MPH EXPECTED INTO THE AFTERNOON. LOCALIZED GUSTS TO
AROUND 45 MPH POSSIBLE THROUGH AROUND MIDDAY. SUBZERO WINDCHILLS
THIS MORNING RISING INTO THE SINGLE DIGITS ABOVE ZERO FOR MOST OF
THE REGION.

AFTERNOON HIGH TEMPS WILL STRUGGLE TO RISE THROUGH THE TEENS
TODAY...APPROACHING 20 DEGREES NEAR THE COAST. FOLLOWED A MAV/MET
BLEND WHICH IS SUPPORTED BY HOURLY GFS LAMP NUMBERS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
HIGH PRESSURE PASSES TO THE SOUTH AS A COLD FRONT APPROACHES FROM
THE NORTH. WINDS TURN TOWARD THE WEST AHEAD OF THE COLD
FRONT...AND LIGHTEN. TEMPS WILL NOT BE QUITE AS COLD WITH LOWS IN
THE TEENS AND 20S. IN FACT...READINGS WILL NOT FALL MUCH AS THE
NIGHT PROGRESSES DUE TO WARM AIR ADVECTION.

ON SUNDAY...HIGH CLOUDS INCREASE AS TEMPS RISE THROUGH THE
20S...INTO THE 30S. STAYED CLOSE TO A MET/MAV MOS BLEND. A FEW
SNOW FLAKES MAY BE OBSERVED OVER NJ AND WESTERN ZONES VERY LATE IN
THE DAY AS LOW LEVEL MOISTURE INCREASES AHEAD OF LOW PRESSURE
RIDING ALONG THE FRONTAL BOUNDARY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
DO NOT SEE A BIG SHIFT IN THE MODELS THIS RUN...AND GENERAL
AGREEMENT IS NOTED. LOW PRESSURE WILL PASS TO THE SOUTH MONDAY.
ANALYSIS OF LOW LEVEL THERMAL FIELDS SUGGESTS SNOW SUNDAY
NIGHT...WITH A WINTRY MIX FOR THE SOUTHERN HALF OF THE FORECAST
AREA MONDAY MORNING. EXPECT A MIX OF SNOW...SLEET AND FREEZING RAIN
FOR A PORTION OF THE AREA. THE EAST END OF LONG ISLAND COULD SEE A
CHANGEOVER TO PLAIN RAIN FOR A TIME.

OVERALL...EXPECT 6 TO 8 INCHES NEAR THE COAST...AND 8 TO 12
INLAND. SOME LIGHT ICING IS POSSIBLE NEAR THE COAST AS WELL. FOR
LONG ISLAND AND NYC...THESE ACCUMULATIONS ARE A TOTAL. THE ACTUAL
AMOUNTS COULD BE LOWER DUE TO RAIN/FREEZING RAIN CHANGEOVER.

FOR THE COAST...SNOW TO BRIEF PD OF RAIN/FZRA AND IP...BEFORE
CHANGING BACK TO SNOW MONDAY AFTN.

INTERIOR...MAINLY SNOW WITH A PERIOD OF SLEET MIXED IN MONDAY MORNING.

TIMING FOR HEAVIEST PRECIP WOULD BE MIDNIGHT THROUGH ABOUT NOON OR
SO MONDAY.

AFTER COLLAB WITH SURROUNDING OFFICES...A WINTER STORM WATCH HAS
BEEN POSTED. START TIME 00Z MONDAY THROUGH 6 PM MONDAY. THIS CAN
BE FINE TUNED AS WE GET CLOSER TO THE EVENT.

OF COURSE ANY SHIFT IN TRACK NORTH OR SOUTH WILL MAKE A BIG
DIFFERENCE AS OUR AREA WILL BE DEALING WITH THE RAIN/SNOW
LINE...WHICH IS ALWAYS DIFFICULT TO FORECAST.

TEMPS ARE A NAM 2M BLEND WITH GRIDDED MOS. HAND EDITS WERE NEEDED
AS WELL. LOWS SUNDAY NIGHT WILL RANGE FROM THE TEENS INLAND TO THE
MID AND UPPER 20S NEAR THE COAST.

ON MONDAY...MID 30S POSSIBLE NEAR THE COAST...ERN LI...AND AROUND
20 WELL INLAND. TEMPS DROP DURING THE AFTERNOON AS THE STORM
PASSES TO THE SE AS COLD AIR RUSHES IN.

AFTER THIS SYSTEM...MONDAY NIGHT UNTIL MIDWEEK...WE WILL BE IN A
QUASI-ZONAL MID LEVEL FLOW. A WEAK LOW AMPLITUDE SHORTWAVE MOVES
ACROSS TUESDAY WITH A LARGER MORE AMPLIFIED SHORTWAVE MOVING
APPROACHING WEDNESDAY NIGHT. THERE WILL BE AN ASSOCIATED COLD
FRONT AT THE SURFACE APPROACHING WEDNESDAY NIGHT INTO THURSDAY.
THERE WILL BE A CHANCE OF SNOW WITH THIS.

FOR LATE IN THE WEEK...A LOW PRESSURE AREA MOVES FAR OFFSHORE...MORE
OFFSHORE WITH THE 12Z ECMWF RUN TODAY...BUT DID NOT WANT TO TOTALLY
MAKE FOR A DRY FORECAST. LEFT IN A CHANCE OF MAINLY SNOW FOR
THURSDAY INTO FRIDAY. HOWEVER...THE MODELS HAVE CONVEYED MORE OF A
PROGRESSIVE SOLUTION AND LESS AMPLIFIED THAN BEFORE SO THE LOW IS
NOT THAT STRONG OFFSHORE AND HIGH PRESSURE COULD PROVE TO BE MORE
DOMINANT IN ALLOWING FOR A DRIER FORECAST.

FOR HIGH TEMPERATURES...BELOW NORMAL OVERALL...MAINLY IN 20S EXCEPT
FOR WEDNESDAY AND THURSDAY WITH LOW TO MID 30S. LOWS ARE FORECAST TO
BE TEENS TO LOWER 20S SUNDAY NIGHT AND WEDNESDAY NIGHT. FOR OTHER
PERIODS...LOW TEMPERATURES ARE FORECAST AS FOLLOWS...SINGLE DIGITS
TO A LITTLE BELOW ZERO MONDAY NIGHT...SINGLE DIGITS TO LOWER TEENS
TUESDAY NIGHT...LOW TO MID TEENS THURSDAY AND FRIDAY NIGHT.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
VFR CONDS THROUGH THE TAF PERIOD AS HIGH PRES BUILDS IN FROM THE
WEST.

WINDS AT OR FAVORING NORTH OF 310 MAG FOR AT LEAST THE FIRST HALF OF
THE AFTERNOON. WINDS COULD START FAVORING SOUTH OF 310 MAG AS EARLY
AS AROUND 21-23Z. WINDS MOSTLY WEST TONIGHT. SUSTAINED WINDS AND
GUSTS GRADUALLY DIMINISH THIS AFTN. FREQUENT GUSTS END BY MIDNIGHT.

VFR FOR MOST OF SUNDAY. A LIGHT SNOW SHOWER POSSIBLE TOWARDS DARK.

.OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY...
.SUNDAY PM...VFR.
.SUNDAY NIGHT-MONDAY...HIGH IMPACT PERIOD. IFR AND SNOW LIKELY. GOOD
CHANCE OF MIXED PCPN MON MORNING AND EARLY AFTN FOR CITY TERMINALS
AND KISP. E-NE G 25-30KT MON AM BCMG N LATE.
.MONDAY NIGHT...BECOMING VFR AS SNOW COMES TO AN END. N-NW G 30KT.
.TUE...VFR.
.WED...VFR LIKELY. CHC SW G 20KT.
.THU...VFR NW G 20KT.

&&

.MARINE...
NW GALES OF TO 45 KT ON THE OCEAN WATERS AND UP TO 40 KT ON ALL
OTHER WATERS THIS MORNING...WILL GRADUALLY SUBSIDE THROUGH THE
AFTERNOON. THE COMBINATION OF ROUGH SEAS...STRONG WINDS...AND
COLD WATER TEMPS WILL ALSO RESULT IN AT LEAST MODERATE FREEZING
SPRAY TODAY.

GUSTY WINDS DIMINISH THIS EVENING...THOUGH A FEW 35 KT GUSTS ARE
POSSIBLE ON THE EASTERN OCEAN WATERS. SMALL CRAFT ADVISORY WIND
GUSTS LIKELY ON THE OCEAN WATERS THROUGH TONIGHT. SEAS WILL ALSO
GRADUALLY SUBSIDE TO LESS THAN 5 FT DURING THE OVERNIGHT HOURS.

TRANQUIL CONDS ON THE WATERS AS HIGH PRES BUILDS OVERHEAD AND
DEPARTS. ANOTHER LOW APPROACHES SUNDAY NIGHT AND MONDAY. CONDS RAMP
UP TO AT LEAST SMALL CRAFT ADVISORY LEVELS MONDAY AND GALES ARE
LIKELY ON ALL WATERS FOR A PERIOD MONDAY NIGHT.

THESE CONDITIONS GRADUALLY TAPER DOWN EARLY TUESDAY. THE RELATIVELY
MORE QUIET PERIOD LOOKS TO BE LATE TUESDAY MORNING THROUGH EARLY
WEDNESDAY MORNING. THERE COULD BE SOME MARGINAL SCA SEAS ON THE
OUTER OCEAN TUESDAY OF AROUND 5 FT. SCA CONDITIONS POSSIBLE ONCE
AGAIN WITH THE APPROACH OF THE COLD FRONT TOWARDS MIDWEEK.

&&

.HYDROLOGY...
GENERALLY AROUND 0.8 TO 1.2 INCHES OF LIQUID FORECAST WITH THE
SYSTEM SUNDAY NIGHT THROUGH MONDAY. A SNOW AND WINTRY MIX EVENT IS
FORECAST. NO HYDROLOGIC ISSUES ARE EXPECTED AT THIS TIME.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH MONDAY
     AFTERNOON FOR CTZ005>012.
NY...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH MONDAY
     AFTERNOON FOR NYZ067>075-078>081-176>179.
NJ...WINTER STORM WATCH FROM SUNDAY EVENING THROUGH MONDAY
     AFTERNOON FOR NJZ002-004-006-103>108.
MARINE...FREEZING SPRAY ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ330-
     335-338-340-345-350-353-355.
     GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ330-335-338-
     340-345-350-353-355.

&&

$$
SYNOPSIS...PW
NEAR TERM...PW
SHORT TERM...PW
LONG TERM...JM/PW
AVIATION...JC
MARINE...MPS
HYDROLOGY...PW





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