Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 091756
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1256 PM EST TUE FEB 9 2016

.SYNOPSIS...
WEAK HIGH PRESSURE WILL REMAIN OVER THE AREA TODAY AS LOW
PRESSURE DEVELOPS OFF THE MID ATLANTIC COAST AND MOVES EAST OUT TO
SEA. ANOTHER LOW WILL DEVELOP JUST SOUTH OF LONG ISLAND TONIGHT
AND PASS EAST ON WEDNESDAY. A WEAK LOW PRESSURE TROUGH WILL REMAIN
OVER THE WATERS FROM WEDNESDAY NIGHT INTO FRIDAY. LOW PRESSURE AND
A STRONG ARCTIC COLD FRONT WILL MOVE THROUGH FRIDAY NIGHT INTO
SATURDAY NIGHT. AN ARCTIC AIR MASS WILL BUILD IN SATURDAY NIGHT
THROUGH MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SOME LIGHT SNOW MAY MOVE INTO WESTERN ZONES LATER IN THE
AFTERNOON...BUT FOR THE MOST PART...DRY CONDS IN PLACE AS WEAK SFC
HIGH PRESSURE WILL OTHERWISE PREVAIL AS DEVELOPING LOW PRESSURE
PASSES WELL TO THE SOUTH. A LINGERING LOW PRESSURE TROUGH IN THE
WAKE OF THE LOW WILL START TO LIFT NORTH LATE IN THE AFTERNOON.

HIGH TEMPS TODAY SHOULD BE 30-35 PER MOS GUIDANCE BLEND.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
AS A DEEP LONGWAVE TROUGH MOVES TOWARD THE NORTHEAST...THE
ASSOCIATED MID LEVEL CLOSED LOW WILL OPEN UP...WITH A STRONG MID
LEVEL VORT MAX ROUNDING THE BASE OF THE TROUGH AND SWING ACROSS
WED MORNING. MEANWHILE AT THE SURFACE...THE INVERTED TROUGH IN THE
WAKE OF THE FIRST LOW WILL CONTINUE TO LIFT SLOWLY NORTH CLOSER
TO THE AREA...WITH A WEAK LOW CENTER ALSO DEVELOPING OFFSHORE IN
RESPONSE TO THE APPROACHING SHORTWAVE. THESE WILL BOTH HELP TO
FOCUS BANDS OF LIGHT TO MODERATE SNOW MAINLY OVER NYC METRO...LONG
ISLAND AND COASTAL SECTIONS TONIGHT INTO WED MORNING. SIDED MOSTLY
WITH A BLEND OF THE 00Z NAM/GFS...WITH THE NAM MOSTLY HAVING HELD
COURSE OVER THE PAST 24 HR AND THE GFS TRENDING NORTH TOWARD A
SIMILAR FCST SOLUTION. FCST SOUNDINGS SHOW BEST LIFT AT TEMPS
IDEAL FOR DENDRITIC SNOW GROWTH...AND ALSO SHOW VERY WEAK STATIC
STABILITY...WITH A DEEP SATURATED LAYER AND MOIST ADIABATIC LAPSE
RATES. SNOWFALL RATES SHOULD BE ENHANCED AS A RESULT LATE TONIGHT
INTO WED MORNING...AND WOULD NOT RULE OUT A RUMBLE OF THUNDER
DURING PERIODS OF HEAVIER SNOW. AS A RESULT...ISSUED A WINTER WX
ADVY FOR NYC METRO...LONG ISLAND AND COASTAL CT FOR TONIGHT INTO
WED MORNING.

THESE INVERTED TROUGHS OFTEN OUT-PERFORM MODEL GUIDANCE AND
SOMETIMES ALSO END UP NORTH OF MODEL FCST...SO THE SITUATION
TONIGHT WILL HAVE TO BE WATCHED CLOSELY. HAD EVEN BRIEFLY
CONSIDERED A WINTER STORM WATCH FOR NYC METRO AND LONG ISLAND
BECAUSE OF THIS...BUT WITH SREF STAYING TO THE SOUTH AND CAM
GUIDANCE NOT PRODUCING APPRECIABLE QPF CONSIDERING THE CONVECTIVE
ASPECT...DECIDED ON THE ADVY AS THE BEST COURSE OF ACTION.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
A LONGWAVE EASTERN TROUGH WILL REMAIN INTO SATURDAY WITH A SERIES
OF SHORTWAVES ROTATING THROUGH THE FLOW. THE UPPER TROUGH AXIS
FINALLY MOVES TO THE EAST SATURDAY NIGHT INTO SUNDAY AS A SURGE OF
ARCTIC AIR...THE COLDEST OF THE SEASON...PUSHES INTO THE NORTHEAST
SATURDAY NIGHT INTO MONDAY. FORECAST AND MODEL GUIDANCE REMAINS
VERY CONSISTENT THROUGH THE EXTENDED PERIOD.

CYCLONIC FLOW REMAINS...AND COLD AIR WILL BE IN PLACE...WITH A
CHANCE OF LIGHT SNOW OR SNOW SHOWERS CONTINUING INTO THURSDAY.
SNOWFALL AMOUNTS ARE EXPECTED TO BE LIGHT...PROBABLY AN INCH OR
SO...MAINLY NORTH AND WEST OF NYC. THE FIRST PUSH OF COLDER AIR
INTO THE AREA MOVES IN FOR THURSDAY BEHIND THE DEPARTING LOW.
THE AREA WILL BE BETWEEN SHORTWAVES THURSDAY NIGHT INTO FRIDAY AS
WEAK SURFACE RIDGING BUILDS IN.

THE NEXT SHORTWAVE ROTATES THROUGH FRIDAY NIGHT INTO SATURDAY NIGHT
WITH A SURFACE LOW TRACKS NORTH OF THE REGION. THIS LOW WILL BRING
AN ARCTIC FRONT THROUGH THE AREA WITH THE COLDEST AIR OF THE SEASON
MOVING IN FOR SATURDAY NIGHT AND REMAINING INTO SUNDAY. THIS LOW
BRINGS ANOTHER CHANCE OF LIGHT SNOW ACROSS THE REGION. ARCTIC HIGH
PRESSURE BUILDS IN SATURDAY NIGHT AND REMAINS INTO THE BEGINNING OF
NEXT WEEK. RIGHT NOW THE CORE OF THE COLDEST AIR LOOKS TO TRACK WEST
OF THE REGION...MOVING THROUGH WESTERN NEW YORK STATE...WESTERN
PENNSYLVANIA AND INTO THE CENTRAL APPALACHIANS.
REGARDLESS...TEMPERATURES WILL BE RUNNING 15 TO AS MUCH AS 25
DEGREES BELOW NORMAL. THERE WILL BE A SLIGHT MODIFICATION TO THE
AIR MASS MONDAY. CURRENTLY WIDESPREAD RECORD LOWS ARE NOT
EXPECTED WITH THE ARCTIC OUTBREAK. THE BEST CHANCE WILL BE
SATURDAY NIGHT/SUNDAY MORNING...SEE THE CLIMATE SECTION FOR
DETAILS.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A LOW PRESSURE TROUGH WILL APPROACH FROM THE SOUTH TODAY AND ENTER
THE REGION TONIGHT.

MOSTLY MVFR...BUT SOME VFR NORTH OF THE CITY THRU MID-LATE
AFTERNOON. FLIGHT CATS LOWER THIS EVENING WITH SNOW.

SNOW ACCUMS IN THE 2-5 INCH RANGE EXPECTED OVERNIGHT INTO WEDS
MORNING.

NE WINDS 10KT OR LESS TO START...THEN BECOMING E 5-10KT LATE THIS
AFTN. LIGHT AND VARIABLE WINDS STARTING AROUND THE ONSET OF SNOW.

...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: ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2
HOURS.

KLGA FCSTER COMMENTS: ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2
HOURS.

KEWR FCSTER COMMENTS: ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2
HOURS.

KTEB FCSTER COMMENTS: ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2
HOURS.

KHPN FCSTER COMMENTS: TIMING OF SUB-VFR COULD BE OFF BY 1-2 HOURS.
ONSET OF SNOW THIS EVENING COULD BE OFF BY 1-2 HOURS.

KISP FCSTER COMMENTS: TEMPO VFR POSSIBLE THIS AFTERNOON. ONSET OF
SNOW THIS EVENING COULD BE OFF BY 1-2H OURS.

.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.WEDS PM...VFR. W GUSTS 20-25KT.
.THU...SLIGHT CHC -SHSN...OTHERWISE VFR. WNW GUSTS 25-30KT.
.FRI...VFR.
.SAT...SLIGHT CHC -SHSN...OTHERWISE VFR. NW GUSTS 25-30KT.
.SUN...VFR. NW GUSTS 20-25KT.

&&

.MARINE...
SCA CONTINUES FOR THE OCEAN WATERS...AND WILL CONTINUE INTO
WEDNESDAY. SEAS 8-10 FT TODAY SHOULD ONLY SLOWLY SUBSIDE BEFORE
STRONG WESTERLY FLOW IN THE WAKE OF DEPARTING LOW PRESSURE BEGINS
LATE DAY WED INTO WED NIGHT...WITH GUSTS UP TO 30 KT ON ALL
WATERS...POSSIBLY REACHING MINIMAL GALE FORCE ON THE OUTER OCEAN
WATERS.

SCA CONDITIONS WILL CONTINUE ON THE OCEAN WATERS THU INTO FRI AS
LOW PRESSURE SLOWLY DEPARTS TO THE EAST. GUSTS THURSDAY ON THE
REMAINDER OF THE FORECAST WATERS MAY REACH SMALL CRAFT LEVELS AS
THE FIRST PUSH OF ARCTIC AIR MOVES IN. THERE MAY BE A BRIEF LULL
IN SMALL CRAFT CONDITIONS LATER FRIDAY INTO FRIDAY NIGHT. ANOTHER
LOW AND AN ARCTIC FRONT MOVE THROUGH THE WATERS LATE FRIDAY NIGHT
INTO SATURDAY WITH SMALL CRAFT CONDITIONS LIKELY ONCE AGAIN.

&&

.HYDROLOGY...
LIQUID EQUIVALENT QPF TONIGHT INTO WED MORNING SHOULD BE LESS THAN
1/2 INCH...ALL IN THE FORM OF SNOW. NO HYDROLOGIC PROBLEMS.

LITTLE PRECIPITATION EXPECTED WED AFTERNOON THROUGH SAT
NIGHT...THEN DRY EARLY NEXT WEEK.

&&

.TIDES/COASTAL FLOODING...
FOR THE HIGH TIDE CYCLE THIS MORNING...SPRING ASTRONOMICAL TIDES
WILL PEAKING. IN ADDITION...WINDS SHOULD VEER MORE TO THE NE AS
ADDITIONAL WAVES OF LOW PRESSURE TRACK TO THE SOUTH OF THE REGION.
WIDESPREAD MINOR COASTAL FLOODING IS EXPECTED FOR MOST OF THE
REGION...WITH MODERATE COASTAL FLOODING FOR THE SOUTH SHORE BAYS
OF LONG ISLAND AND NYC. THE HIGH END OF THE FORECAST RANGE COULD
COME CLOSE TO THE WATER LEVELS REACHED DURING YESTERDAYS MORNING
FOR THE BAYS OF NYC AND WESTERN LONG ISLAND.

THEREAFTER...WE ARE GENERALLY LOOKING MINOR TO LOCALLY MODERATE
COASTAL FLOODING CONCERNS WITH TUESDAY EVENINGS HIGH TIDE CYCLE.

ASTRONOMICAL TIDES WILL GRADUALLY CONTINUE TO LOWER...WITH SOME
ADDITIONAL COASTAL FLOODING POSSIBLE INTO THE WED MORNING HIGH
TIDE CYCLE.

HIGH SURF OF 6 TO 10 FT WILL CONTINUE TODAY A MODERATE THREAT FOR
DUNE TOE EROSION ALONG THE ATLANTIC OCEAN BEACHES...AND A LOCALIZED
POTENTIAL FOR OVERWASHES ON FIRE ISLAND. THIS IS BASED ON MODELED
IMPACTS OF GALE CENTER FROM THE USGS COASTAL CHANGE HAZARDS PORTAL.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
     WEDNESDAY FOR CTZ009>012.
     COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
     CTZ009-010.
     COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 2 AM EST
     WEDNESDAY FOR CTZ009.
NY...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
     WEDNESDAY FOR NYZ069>075-078>081-176>179.
     COASTAL FLOOD ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
     NYZ071-073-078-079-081-177.
     COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO MIDNIGHT EST
     TONIGHT FOR NYZ074-075-080-178-179.
     COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 2 AM EST
     WEDNESDAY FOR NYZ071-078-177.
     COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO 2 AM EST
     WEDNESDAY FOR NYZ081.
NJ...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON EST
     WEDNESDAY FOR NJZ002-004-006-103>108.
     COASTAL FLOOD ADVISORY FROM 8 PM THIS EVENING TO MIDNIGHT EST
     TONIGHT FOR NJZ006-106-108.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR ANZ350-353-
     355.

&&

$$
SYNOPSIS...MET
NEAR TERM...GOODMAN/MPS
SHORT TERM...GOODMAN
LONG TERM...MET
AVIATION...JC
MARINE...GOODMAN/MET
HYDROLOGY...GOODMAN/MET
TIDES/COASTAL FLOODING...



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