Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 011152
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
652 AM EST SUN FEB 1 2015

.SYNOPSIS...
A COLD FRONT MOVES ACROSS THE AREA TODAY AS HIGH PRESSURE BUILDS
TO THE NORTH. LOW PRESSURE APPROACHES FROM THE OHIO VALLEY TONIGHT
AND PASSES JUST SOUTH OF LONG ISLAND MONDAY. THE LOW TRACKS WELL
TO THE EAST MONDAY NIGHT. HIGH PRESSURE BUILDS TO THE SOUTH AND
EAST TUESDAY AND TUESDAY NIGHT. AN ARCTIC FRONT APPROACHES FROM
THE NORTHWEST WEDNESDAY...THEN PUSHES THROUGH THE AREA WEDNESDAY
NIGHT. CANADIAN HIGH PRESSURE BUILDS IN THURSDAY THROUGH
FRIDAY...AS LOW PRESSURE TRACKS WELL TO THE SOUTHEAST. THIS HIGH
BUILDS TO THE SOUTH FRIDAY NIGHT. A COLD FRONT APPROACHES FROM THE
NORTH ON SATURDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WEAK RIDGING ALOFT AHEAD OF UPSTREAM TROUGH CAN BE EXPECTED TODAY.
MOISTURE INCREASES AHEAD OF AN AREA OF LOW PRESSURE AND LIFT ALONG
THE FRONTAL BOUNDARY.

SFC HIGH PRESSURE MOVES TO THE SOUTH...WITH ANOTHER AREA OF HIGH
PRESSURE BUILDING NORTH OF THE GREAT LAKES REGION. IN
BETWEEN...FRONTAL BOUNDARY PASSES THROUGH AND REMAINS TO THE SOUTH
TODAY.

CHILLY MORNING TEMPS WILL RISE TO AROUND OR INTO THE LOWER 30S TODAY
PER MOS BLEND.

MOST OF THE DAY WILL BE DRY...ALTHOUGH A FEW SNOW FLAKES MAY BE
OBSERVED LATE FOR WESTERN SECTIONS AHEAD OF THE TROUGH AND IN
RESPONSE TO WEAK LIFT IN WARM AIR ADVECTION.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
CHALLENGING WINTER FORECAST...WITH MIXED PRECIPITATION TYPE TO DEAL
WITH THIS TIME FRAME.

A SLIGHT NORTHWARD TREND TO THE SFC LOW TRACK IS NOTED.

STRONG LIFT AHEAD OF TROUGH...WITH PLENTY OF MOISTURE TAPPED IN FROM
THE SOUTH...WILL SET THE STAGE FOR A HEAVY PRECIP EVENT.
ANALYSIS OF 00Z NWP SUITE INDICATES MID AND UPPER LEVEL TROUGH
MOVES QUICKLY ACROSS THE MID SECTION OF THE COUNTRY THIS
EVENING...TRACKING TOWARD THE EAST COAST BY MONDAY AFTERNOON.
SURFACE LOW ALONG A FRONTAL BOUNDARY OVER THE OHIO VALLEY THIS
EVENING MOVES EAST TRACKING ACROSS SRN PA TOWARD THE SRN OR
CENTRAL NJ COAST EARLY MONDAY. THE LOW TRACKS JUST SOUTH MONDAY
AFTERNOON.

THE MID/UPPER LEVEL TROUGH MOVES THROUGH BY MONDAY EVENING...WITH
SFC LOW TRACKING WELL TO THE EAST.

VERY TOUGH FORECAST FOR MULTIPLE REASONS. MODELS DO INDICATE LOW
LEVEL WARM AIR ADVECTION OCCURRING AS H8 LOW TRACKS OVER OR JUST
NORTH OF NYC. AT THE SURFACE...WINDS REMAIN GENERALLY FROM THE EAST
TONIGHT AHEAD OF THE LOW AND TO THE NORTH OF THE FRONTAL BOUNDARY.

BY MONDAY...ENOUGH WARM AIR ALOFT MOVES IN...WITH NAM AND ECMWF
FAIRLY CLOSE WITH REGARD TO TEMPS ALOFT. GFS IS SLIGHTLY WARMER.
LOOKING AT SFC AND BOUNDARY LAYER...FOLLOWED A GRIDDED MOS...NAM
DOWNSCALE BLEND FOR SLOW WARMING IN EAST FLOW...MAINLY FOR EASTERN
LONG ISLAND AND POSSIBLY INTO PORTIONS OF SOUTHERN LONG ISLAND AND
SRN PORTIONS OF NYC.

INTERESTINGLY...HIGH RES ARW AND NMM TRACK THE LOW JUST
SOUTH...BUT PROG THE COASTAL FRONT ACROSS LONG ISLAND...WHICH
SETS UP A LARGE TEMPERATURE GRADIENT ON EITHER SIDE OF THE FRONT.
TEMPS IN THE 40S AS WINDS TURN SOUTH. THIS OBVIOUSLY WOULD BE
PROBLEMATIC AND WOULD REQUIRE A HUGE SHIFT IN THE FORECAST.
AGAIN...WILL FOLLOW THE NAM/GFS/ECMWF IN KEEPING THE LOW AND CSTL
FRONT JUST SOUTH...BUT WARMING EAST END OF LI AND SRN LI
SUFFICIENTLY TO RESULT IN RAIN. ACROSS THE INTERIOR...ENOUGH WARM
AIR ALOFT FOR SNOW MIXING WITH SLEET AND FREEZING
RAIN...STRETCHING SW TO NE ACROSS THE AREA.

GIVEN COLD WATER TEMPS...WOULD BELIEVE TEMPS DO NOT RISE MUCH
ABOVE 32 FOR LONG ISLAND AND INTO NYC. WILL CONVERT THE WATCHES TO
WARNINGS...EXCEPT EASTERN LONG ISLAND...SOUTHERN SUFFOLK AND
SOUTHERN NASSAU. GIVEN THE HIGH LEVEL OF UNCERTAINTY...WILL ALLOW
THE DAY SHIFT ONE MORE LOOK TO DETERMINE CONVERSION TO WARNINGS OR
TO ADVISORIES. ANY FURTHER NORTH SHIFT TO SFC LOW AND H8 LOW WOULD
RESULT IN MORE LIQUID.

IN ADDITION...FREEZING RAIN A CONCERN FOR A GOOD PORTION OF THE AREA.

THE BOTTOM LINE IS...HIGH IMPACT FOR MORNING COMMUTE WARRANTS A
WARNING FOR MOST OF THE AREA. CLOSER TO THE COAST...SNOW TO
RAIN/FZRA/IP. THEN BACK TO SNOW BEFORE ENDING AS DEFORMATION BAND
MOVES THROUGH ON THE BACK SIDE AS THE LOW DEPARTS LATE IN THE DAY
MONDAY.

INTERIOR...MAINLY SNOW...WITH POSSIBLY SOME SLEET MONDAY MORNING.

EASTERN/SRN LONG ISLAND...SNOW TO RAIN OR FREEZING RAIN (DEPENDING
ON THOSE SFC TEMPS)...THEN POSSIBLY BACK TO SNOW.

***IT IS IMPORTANT TO NOTE THAT MANY COASTAL AREA SNOW TOTAL
 FORECASTS ARE FOR SNOW AHEAD OF WINTRY MIX TRANSITION...AND AFTER
 WINTRY MIX CHANGES BACK TO SNOW. HOWEVER...ANY RAIN WILL LIKELY
 WASH THE SNOW AWAY...LEAVING SLUSHY CONDITIONS AND LOWER TOTALS AS
 A RESULT***

SO...MORNING COMMUTE WILL LIKELY BE A MESS ALL CWA. THE AFTERNOON
COMMUTE WILL LIKELY BE PROBLEMATIC AS WELL FOR MUCH OF THE AREA.
ANY LEFTOVER SLUSH WILL FREEZE AS ARCTIC AIR RUSHES BACK IN.
EXPECT ICY CONDITIONS LATE IN THE DAY...ESPECIALLY FOR AREAS THAT
CHANGE TO RAIN LATE MORNING/EARLY AFTERNOON.

HEAVIEST PRECIP IS LATE TONIGHT (09-11Z THROUGH 16-18Z) WHEN
GREATEST LIFT IS REALIZED.

ANY LINGERING LIGHT SNOW MONDAY EVENING ENDS AS THE TROUGH MOVES
EAST/ GUSTY NORTHERLY FLOW WILL USHER IN VERY COLD AIR. LOW TEMPS
IN THE SINGLE DIGITS TO THE TEENS.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
ZONAL FLOW ALOFT SHOULD KEEP THINGS DRY TUESDAY AND TUESDAY NIGHT. A
WEAK SHORTWAVE PASSES ON WEDNESDAY...WITH A STRONGER SHORTWAVE
APPROACHING WEDNESDAY NIGHT...JUST BEHIND AN ARCTIC COLD FRONT AT
THE SURFACE. THERE SHOULD BE ENOUGH FORCING WITH THE SHORTWAVES AND
THE FRONT TO PRODUCE ISOLD-SCT -SHSN WEDNESDAY AND WEDNESDAY NIGHT.

THERE REMAIN MODEL DIFFERENCES FROM THURSDAY ON. BOTH THE ECMWF AND
CMC SUGGEST THAT THE ARCTIC FRONT BECOME AN ANAFRONT WITH SNOW
BEHIND THE FRONT THURSDAY-THURSDAY NIGHT...AND THE CMC GOES FARTHER
AND BRINGS A COASTAL LOW ALONG IT CLOSE ENOUGH TO IMPACT THE AREA.
THE GFS GENERALLY KEEP THINGS DRY THURSDAY/THURSDAY NIGHT. FOR NOW
WENT WITH CHANCE POPS ON THURSDAY...EXCEPT SLIGHT CHANCE FAR N
TIER...THEN SLIGHT CHANCE POPS THURSDAY NIGHT...EXCEPT DRY FAR NNW
TIER OF THE CWA.

ALL MODELS AGREE SHOULD BE DRY FRIDAY-SATURDAY ON NW FLOW ALOFT.

MAIN STORY OF THE EXTENDED WILL BE BITTERLY COLD AIR ARRIVING
WEDNESDAY NIGHT AND LASTING THROUGH FRIDAY NIGHT. HIGHS WILL
STRUGGLE TO REACH THE UPPER TEENS TO LOWER 20S AND LOWS WILL
GENERALLY BE IN THE SINGLE DIGITS THURSDAY AND FRIDAY NIGHT. WIND
CHILLS SHOULD BE BELOW ZERO THURSDAY NIGHT/FRIDAY MORNING...AND
POSSIBLY BE NEAR ADVISORY CRITERIA OVER NW INTERIOR ZONES.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
**HIGH IMPACT EVENT TONIGHT THROUGH MONDAY**

HIGH PRES SOUTH OF THE AREA WEAKENS AND MOVES OFFSHORE TODAY. LOW
PRES OVER THE MIDWEST MOVES EAST TODAY...AND A WARM FRONT
EXTENDING AHEAD OF THE LOW PUSHES INTO THE TERMINALS FROM WEST TO
EAST BY THIS EVENING. LIGHT SNOW IS POSSIBLE LATE THIS
AFTERNOON...BUT STEADY AND MORE WIDESPREAD SNOW PUSHES INTO
WESTERN TERMINALS FROM 02-04Z MONDAY AND INTO EASTERN TERMINALS
FROM 03-05Z.

SNOW MAY BE HEAVY AT TIMES DURING THE OVERNIGHT HOURS.

FOR THE 30 HR TAFS...SNOW WILL MIX WITH FREEZING RAIN MONDAY
MORNING...AND SNOW/FREEZING RAIN WILL LIFT TO THE NORTH THROUGHOUT
THE MORNING.

WEST WINDS 10 KT OR LESS TODAY WILL BECOME LGT/VRB THIS EVENING.
LATER TONIGHT...EAST WINDS INCREASE TO 10-15 KT.

.OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
.MONDAY...SNOW BECOMES A WINTRY MIX OF SNOW/SLEET/FREEZING RAIN
FOR ALL BUT KSWF...WHICH WILL REMAIN ALL SNOW FOR THE EVENT.
RUNWAY ACCUMULATIONS WILL RANGE FROM 3-5" FOR KJFK/KISP...6-8" FOR
KLGA/KEWR/KTEB/KHPN/KBDR/KGON...AND UP TO 12" FOR KSWF. IN
ADDITION...UP TO 1/4" ICE POSSIBLE FOR ALL BUT KSWF. PRECIP
CHANGES BACK TO ALL SNOW THROUGHOUT MONDAY EVENING BEFORE ENDING.
N WINDS 10-15 KT WITH 20-25 KT GUSTS.
.MONDAY NIGHT...ANY LINGERING SNOW SHOWERS END...AND CONDS IMPROVE
TO VFR. NW WINDS 15-20 KT WITH 25-35 KT GUSTS.
.TUESDAY...VFR.
.WEDNESDAY...VFR. A CHANCE OF SNOW SHOWERS WEDNESDAY AFTERNOON AND
WEDNESDAY NIGHT WITH LOCALLY MVFR TO IFR CONDITIONS.
.THURSDAY...VFR. NW GUSTS 20 KT.

&&

.MARINE...
WINDS AND SEAS HAVE FALLEN BELOW SCA LEVELS ON THE COASTAL OCEAN
WATERS. THE REGION WILL BE UNDER A RELATIVELY RELAXED PRESSURE
GRADIENT THROUGH THIS EVENING...SO SUB-SMALL CRAFT CONDITIONS ARE
EXPECTED.

WINDS INCREASE TO SMALL CRAFT LEVELS ON ALL WATERS AFTER MIDNIGHT
AND PERSIST THROUGH MONDAY...SO A SMALL CRAFT ADVISORY HAS BEEN
HOISTED ACCORDINGLY. GUSTS TO GALE FORCE ARE PROBABLE MONDAY NIGHT
ON THE COASTAL OCEAN WATERS...SO A GALE WATCH HAS BEEN ISSUED THEN
FOR THOSE WATERS. FOR THE NON-OCEAN WATERS...SMALL CRAFT CONDITIONS
ARE EXPECTED TO CONTINUE...SO THE SMALL CRAFT ADVISORY FOR THESE
WATERS LAST THROUGH THEN. THERE IS A SMALL CHANCE FOR GALE FORCE
WIND GUSTS ON THE NON-OCEAN WATERS AS WELL MONDAY NIGHT.

SMALL CRAFT CONDITIONS WILL LIKELY CONTINUE ON ALL WATERS
TUESDAY...AND POSSIBLY GALE FORCE WINDS GUSTS IN THE MORNING ON THE
COASTAL OCEAN WATERS. CONFIDENCE IN THIS IS NOT QUITE HIGH ENOUGH
FOR ANY HEADLINES ON TUESDAY YET.

SUB-SMALL CRAFT CONDITIONS ARE EXPECTED ON THE NON-OCEAN WATERS
TUESDAY NIGHT-THURSDAY WITH WINDS 15 KT OR LESS. ON THE OCEAN WATERS
SMALL CRAFT LEVEL SEAS ARE POSSIBLE THROUGH THE TIME FRAME...WITH
THE BEST CHANCE WEDNESDAY-THURSDAY THOUGH A COMBINATION OF WINDS
JUST UNDER SMALL CRAFT LEVELS AND SWELLS.

&&

.HYDROLOGY...
GENERALLY 1 TO 1 1/2 INCHES OF LIQUID FORECAST WITH THE SYSTEM
TONIGHT THROUGH MONDAY. MOST OF THIS WILL BE SNOW AND SLEET
ACROSS NE NJ...LOWER HUDSON VALLEY AND CT.

ACROSS LI/NYC THERE IS A POTENTIAL FOR A PERIOD OF HEAVY
RAIN. AS SUCH...URBAN FLOODING ISSUES ARE POSSIBLE...ESPECIALLY
DUE TO CLOGGED SNOW COVERED DRAINS.

NO SIGNIFICANT WIDESPREAD PCPN IS FORECAST FOR THE REMAINDER OF THE
PERIOD.

&&

.TIDES/COASTAL FLOODING...
AT THIS TIME IT APPEARS THAT FOR THE HIGH TIDE ON MONDAY...THAT
DEPARTURES WILL REMAIN 1 TO 1.5 FEET BELOW THAT REQUIRED FOR COASTAL
FLOODING. WITH DEPARTURES OF 1.5-2 FT REQUIRED AND ONLY .5 TO 1 FT
DEPARTURES CURRENTLY FORECAST.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 6 PM EST MONDAY
     FOR CTZ005>012.
NY...WINTER STORM WATCH FROM THIS EVENING THROUGH MONDAY AFTERNOON
     FOR NYZ079>081-179.
     WINTER STORM WARNING FROM 7 PM THIS EVENING TO 6 PM EST MONDAY
     FOR NYZ067>075-078-176>178.
NJ...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 6 PM EST MONDAY
     FOR NJZ002-004-006-103>108.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST TUESDAY
     FOR ANZ330-335-338-340-345.
     GALE WATCH FROM MONDAY EVENING THROUGH LATE MONDAY NIGHT FOR
     ANZ350-353-355.
     SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST MONDAY
     FOR ANZ350-353-355.

&&

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









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