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Area Forecast Discussion
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000
FXUS61 KOKX 260302
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1002 PM EST TUE NOV 25 2014

.SYNOPSIS...
WEAK HIGH PRESSURE BRIEFLY BUILDS ACROSS THE AREA TONIGHT...WHILE
LOW PRESSURE DEVELOPS ALONG THE SOUTHEAST COAST. THE LOW WILL
DEEPEN AND TRACK NORTHEAST ON WEDNESDAY...PASSING JUST EAST OF
THE SOUTHERN NEW ENGLAND COAST IN THE EVENING. THE LOW THEN TRACKS
THROUGH THE CANADIAN MARITIME THURSDAY. HIGH PRESSURE THEN BUILDS
IN BEHIND THE DEPARTING LOW FRIDAY AND SATURDAY. LOW PRESSURE
MOVES WELL TO THE NORTH AND WEST SUNDAY AND MONDAY...BRINGING A
WARM FRONT THROUGH SUNDAY...FOLLOWED BY A COLD FRONT MONDAY. HIGH
PRESSURE BUILDS IN TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CLOUDS INCREASE THROUGHOUT THE NIGHT AS LOW PRES DEVELOPS AND
STRENGTHENS OFF THE SOUTHEAST U.S. COAST. SFC DEW POINTS ARE SLOWLY
CREEPING UP...BUT IT STILL REMAINS QUITE DRY LOCALLY...AND THERE
IS LITTLE...IF ANY...RAIN ALONG THE EASTERN SEABOARD. NEAREST RAIN
IS OVER THE CAROLINAS. THEREFORE...IT WILL TAKE SOME TIME FOR
MEASURABLE RAINFALL TO REACH NYC AND LONG ISLAND...SO WILL PUSH
OFF CHANCE POPS UNTIL JUST PRIOR TO DAYBREAK.

TEMPS ACROSS THE INTERIOR HAVE DROPPED INTO THE LOWER 30S...BUT
TEMPS THERE SHOULD REBOUND BY A FEW DEGREES OR SO AS CLOUDS
SPREAD NORTH. OTHERWISE...LOWS WILL DROP INTO THE MID TO UPPER
30S. 

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
SIGNIFICANT WINTER STORM WILL TRACK NORTHEAST JUST OFF THE
EASTERN SEABOARD ON WEDNESDAY. THERE IS GOOD MODEL AGREEMENT ON
TAKING THE LOW JUST INSIDE THE BENCHMARK WED NIGHT...40N...70W.
THE REAL DIFFICULT PART OF THE FORECAST IS RESOLVING THERMO
PROFILES WITH NO REAL SOURCE OF LOW-LEVEL COLD AIR. EVENT WILL BE
HEAVILY DEPENDENT ON DYNAMICAL COOLING AND WHERE BANDING SETS UP.
IN ADDITION...ANY DEVIATION RIGHT OR LEFT OF THE LOW TRACK COULD
ALTER THERMO PROFILES BY JUST A DEGREE OR TWO...ALL THAT WILL BE
NEEDED FOR A SIGNIFICANT CHANGE TO THE FORECAST. HIGHEST
CONFIDENCE OF REACHING WARNING LEVEL SNOWS IS ACROSS THE INTERIOR
OF SOUTHERN CT...THE LOWER HUDSON VALLEY...AND PORTIONS OF NE NJ.
NY METRO AND MUCH OF COASTAL CT HAVE BEEN PLACED INTO AN ADVISORY
DUE TO A LONGER TRANSITION TIME TO SNOW AND FREQUENT MIXING WITH
RAIN. THIS WILL BE A HEAVY WET SNOW...POTENTIALLY CAUSING POWER
OUTAGES AND DOWNED TREE LIMBS.

AS PREVIOUSLY MENTIONED...MODELS HAVE COME INTO CONSENSUS WITH A
LOW TRACK JUST INSIDE THE BENCHMARK WED EVE. THERE IS NO POLAR AIR
IN PLACE FOR LOW-LEVEL COLD AIR WITH THE MODELS VARYING WITH AN
ELEVATED WARM LAYER IN THE MID LEVELS. THE 18Z NAM WRF IS THE MOST
AGGRESSIVE WITH THIS WARMING WITH 3 DEG C AT 700 MB ACROSS THE NYC
METRO. IRONICALLY...THE NAM ABOUT 24 HOURS AGO WAS THE COLDEST
SOLUTION WITH A TRACK A BIT FARTHER EAST. IT STILL REMAINS THE
COLDEST IN THE BOUNDARY LAYER...WHICH FOR THE MOST PART IS THE
HANG UP FOR THE NYC METRO...COASTAL CT...AND WESTERN LI...WHICH
ARE GENERALLY BELOW FREEZING ABOVE 1500 FT. THE BOUNDARY LAYER
WILL BE CRITICAL HERE. AS FOR THE ELEVATED WARM LAYER FROM THE
LATEST NAM...WILL HAVE TO SEE IF THIS SHOWS UP IN THE 00Z
CYCLE...PARTICULARLY THE GFS AND ECMWF. THE NAM IS CLEARLY MORE
ROBUST WITH AN 85 TO 90 KT JET AT 650 MB. THE ECMWF IS ABOUT 10 TO
15 KT WEAKER AND FARTHER OFFSHORE...AND THE GFS IS EVEN FARTHER
EAST. THIS COULD BE HUGE PLAY MAKER. IN ADDITION...WITH A
MARGINALLY COLD AIR MASS IN PLACE...850-500 MB FRONTOGENESIS COULD
OVERWHELM THE COLUMN WITH SIGNIFICANT SNOWS EVEN INTO THE NYC
METRO. FOR NOW WILL KEEP ADVISORY LEVEL SNOWS AT THE COAST AND
WARNING LEVEL ACROSS INLAND AREAS. EASTERN LI AND SE CT WILL
SEE THE LEAST AMOUNT OF SNOWFALL UNLESS A SIGNIFICANT TRACK
CHANGE ENSUES IN SUBSEQUENT CYCLES...WHICH IS NOT LIKELY.

PCPN WILL BREAK OUT BY DAYBREAK AND BE HEAVIEST DURING THE MORNING
AND AFTERNOON HOURS. 

HIGHEST SNOWFALL TOTALS WILL RANGE FROM 6 TO 10 INCHES IN THE
LOWER HUDSON VALLEY...TO 2 TO 5 INCHES IN THE ADVISORY AREA.

STAYED AWAY FROM MOS TEMPS IN THIS SITUATION AND USED THE NAM 2
METER TEMPS FOR BOUNDARY LAYER AND A BLEND OF THE GFS/ECMWF FOR
THERMO PROFILES AND PTYPE. TEMPS WILL SLOWLY FALL INTO THE LOWER
AND MID 30S BY MID AFT WED.

EXPECT A TRANSITION TO ALL SNOW ON THE BACKSIDE WED NIGHT WITH
MINOR ADDITIONAL ACCUMULATIONS POSSIBLE. LOWS WILL RANGE FROM THE
MID 20S TO LOWER 30S.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
AN UPPER TROUGH WILL STILL BE CROSSING THE NORTHEAST THURSDAY INTO 
THURSDAY EVENING WITH THE SURFACE LOW DEPARTING TO THE NORTHEAST. 
THERE  WILL BE SOME WEAK INSTABILITY ALONG WITH WEAK LIFT WITH THE 
UPPER TROUGH AND A WEAK SURFACE TROUGH IN THE VICINITY BEHIND THE 
LOW. BOTH THE GFS AND ECMWF HAVE LIGHT QPF...AND SOME FLURRIES WILL 
BE POSSIBLE INTO THURSDAY EVENING.

THE UPPER TROUGH AXIS MOVES OFF THE COAST THURSDAY NIGHT WITH THE 
FLOW BECOMING ZONAL INTO EARLY NEXT WEEK. SOME WEAK RIDGING BUILDS 
TUESDAY AS A DEEPENING TROUGH MOVES INTO THE PACIFIC NORTHWEST AND 
ROCKY MOUNTAIN RANGE. A VERY WEAK SHORTWAVE MOVE QUICKLY THROUGH THE 
ZONAL FLOW...NORTH OF THE AREA...SATURDAY NIGHT INTO SUNDAY. A THE 
SURFACE A WARM FRONT CROSSES THE REGION SUNDAY FOLLOWED BY A COLD 
FRONT LATE SUNDAY NIGHT INTO MONDAY MORNING. THERE WILL BE A SLIGHT 
CHANCE OF RAIN SHOWERS SUNDAY INTO MONDAY.

FOR TEMPERATURES THURSDAY THROUGH FRIDAY UNDERCUT GUIDANCE BY A FEW 
DEGREES INLAND WITH THE POTENTIAL OF SNOW COVER AND LIGHT NORTHWEST 
FLOW. OTHERWISE FOLLOWED WPC GUIDANCE FRIDAY NIGHT THROUGH
TUESDAY.

&&

.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
***HIGH IMPACT WINTER WEATHER EVENT WEDNESDAY***

LOW PRES WILL TRACK FROM NEAR HATTERAS WED MRNG...TO NEAR
CAPE COD WED NGT.

VFR MOST OF TNGT...FALLING TO MVFR AS PCPN STARTS AROUND 12Z...TO
IFR OR LWR THEREAFTER TIL AFT 00Z WHEN PCPN TAPERS OFF AND CIGS
IMPROVE TO MVFR.

FOR THE CITY INTO KHPN AND KBDR...PCPN STARTS MAINLY AS RAIN THEN
TRANSITIONS TO SNOW BY AROUND 15Z. SLEET AND RAIN MAY THEN MIX IN
DURING THE AFTN BEFORE ENDING AS ALL SNOW LATE IN THE AFTN AND
INTO THE EVE.

FOR KSWF...ALL SNOW.

FOR KISP AND KGON...TRANSITION TO SNOW LATER THAN THE CITY...WITH
MORE POTENTIAL SLEET AND RAIN MIX IN THE AFTN. POTENTIAL FOR
PERIODS OF HVY RAIN.

MOST LIKELY RUNWAY ACCUMULATIONS 3-6 INCHES NYC METRO TERMINALS...
8-11 INCHES KSWF/KHPN...3-6 INCHES KBDR...1-2 INCHES KISP/KGON.

.OUTLOOK FOR 00Z THU THROUGH SAT...

.WED NIGHT...IMPROVERMENT TO MVFR AFT ABOUT 2Z. WINDS BECOMING NW
THEN DIMINISHING AFTER MIDNIGHT.

.THU-THU NIGHT...LINGERING SNOW SHOWERS POSSIBLE IN THE MORNING
WITH MVFR CONDS...THEN VFR. 

.FRI-SUNDAY...VFR.

&&

.MARINE...
A COASTAL LOW BRINGS GALE CONDITIONS TO THE COASTAL OCEAN WATERS
WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. THE GALE WARNING REMAINS
UNCHANGED. FOR THE REMAINING WATERS...A SCA WILL BE IN EFFECT FOR
ROUGHLY THE SAME PERIOD.

A NORTHWEST FLOW BEHIND DEPARTING LOW PRESSURE THURSDAY WILL BE
BELOW SMALL CRAFT LEVELS...HOWEVER SEAS ON THE OCEAN WILL STILL BE
AT SMALL CRAFT LEVELS AND SLOWLY SUBSIDING...FALLING BELOW BY
FRIDAY MORNING AS HIGH PRESSURE BUILDS IN.

THEN WIND AND SEAS WILL REMAIN BELOW SMALL CRAFT THE REMAINDER OF 
FRIDAY INTO SATURDAY. A RETURN FLOW DEVELOPS SATURDAY AS THE HIGH 
MOVES OFF THE COAST. A SOUTHWEST FLOW INCREASES AS LOW PRESSURE 
MOVES THROUGH THE GREAT LAKES REGION SATURDAY INTO SUNDAY. SOME 
GUSTS ON THE OCEAN WATERS MAY BE NEAR SMALL CRAFT LATER SATURDAY 
INTO SUNDAY...AND SEAS WILL BE BUILDING TO SMALL CRAFT LATE SATURDAY 
AND REMAIN INTO SUNDAY.

&&

.HYDROLOGY...
FOR WEDS AND WEDS NIGHT...EXPECTING A LIQUID EQUIVALENT
PRECIPITATION AMOUNTS AVERAGING AROUND 1.0 TO 1.5. THE HIGHEST QPF
AMOUNTS AREA CURRENTLY EXPECTED OVER EASTERN CT/LONG ISLAND AND
THE LOWEST OVER FAR WESTERN PORTIONS OF THE TRI-STATE.

OVER THE INTERIOR MOST OF THIS WILL FALL IN THE FORM OF SNOW...SO 
LITTLE IF ANY IMMEDIATE HYDROLOGIC IMPACT IS EXPECTED THERE. FARTHER 
TO THE S/E...BASICALLY ALONG AND E OF I-95...THERE WILL BE A A MIX 
OF RAIN AND SNOW. THIS COULD CAUSE MINOR FLOODING OF URBAN/POOR 
DRAINAGE AREAS.

THURSDAY THROUGH SUNDAY...VERY LIGHT QPF AMOUNTS ARE 
POSSIBLE...THURSDAY...SATURDAY AND SUNDAY.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 1 AM EST THURSDAY 
     FOR CTZ005>007.
     WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 1 AM EST 
     THURSDAY FOR CTZ008>011.
NY...WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 1 AM EST THURSDAY 
     FOR NYZ067>070.
     WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 1 AM EST 
     THURSDAY FOR NYZ071>075-176>178.
NJ...WINTER STORM WARNING FROM 7 AM WEDNESDAY TO 1 AM EST THURSDAY 
     FOR NJZ002-004-103-105-107.
     WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO 1 AM EST 
     THURSDAY FOR NJZ006-104-106-108.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM WEDNESDAY TO 1 AM EST THURSDAY 
     FOR ANZ330-335-338-340-345.
     SMALL CRAFT ADVISORY UNTIL 11 AM EST WEDNESDAY FOR ANZ350-353-
     355.
     GALE WARNING FROM 11 AM WEDNESDAY TO MIDNIGHT EST WEDNESDAY 
     NIGHT FOR ANZ350-353-355.

&&

$$
SYNOPSIS...MET/DW
NEAR TERM...MPS
SHORT TERM...MPS
LONG TERM...MET
AVIATION...JMC/GOODMAN
MARINE...MET/DW
HYDROLOGY...MET/DW








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