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Area Forecast Discussion
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000
FXUS61 KOKX 041651
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1151 AM EST WED MAR 4 2015

.SYNOPSIS...
DEEPENING LOW PRESSURE TRACKS ACROSS EASTERN CANADA TODAY WITH A
COLD FRONTAL BOUNDARY APPROACHING AS A WAVE OF LOW PRESSURE
DEVELOPS ALONG IT SOUTHWEST OF THE REGION. THE COLD FRONT SLIDES TO
THE SOUTHEAST TONIGHT...WITH WAVES OF LOW PRESSURE TRACKING ALONG
IT INTO THURSDAY. CANADIAN HIGH PRESSURE THEN BUILDS IN THROUGH
THURSDAY NIGHT...THEN SLIDES TO OUR SOUTH THROUGH FRIDAY NIGHT. A
SERIES OF WEAK COLD FRONTS CROSS THE REGION THIS WEEKEND INTO
EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED NEAR TERM GRIDS BASED ON LATEST TRENDS. HAVE ADJUSTED POPS
DOWNWARD A BIT THIS AFTERNOON WITH LIKELY POPS ACROSS THE SOUTH
AND CHANCE NORTH. HAVE ALSO RAISED HIGH TEMPERATURES A FEW
DEGREES. THIS GIVES READINGS IN THE UPPER 30S AND LOWER 40S.
OTHERWISE...FORECAST REMAINS ON TRACK. 

THE UPPER LEVEL JET STREAK OF AROUND 200 KT WILL BE INTERMITTENT
LIGHT RAIN...ESPECIALLY ACROSS THE SOUTH. 

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
MODELS IN GOOD AGREEMENT WITH NORTHERN STREAM ENERGY DIGGING DOWN 
THE FRONT RANGE OF THE ROCKIES INTO NORTHERN PLAINS/UPPER GREAT 
LAKES TODAY...INTERACTING WITH A SW US LOW...AND THEN GRADUALLY 
LIFTING ACROSS THE US TO EAST COAST BY THURSDAY NIGHT. 

HAVE STAYED CLOSE TO ENSEMBLE MEANS...WITH A REINFORCING COLD FRONT 
MOVING SOUTH OF THE REGION THIS EVE WITH FALLING TEMPS TONIGHT. A 
SERIES OF WAVES WILL DEVELOP ALONG A STATIONARY FRONT TO THE SOUTH 
TRACKING NE THROUGH THE MID ATLANTIC...AHEAD OF APPROACHING UPPER
TROUGH AXIS AND AS THE REGION FALLS UNDER FAVORABLE ENTRANCE
REGION OF A 175-200KT UPPER JET.

BIGGEST UNCERTAINTY EXISTS IN QPF...WITH MODELS WOBBLING BACK AND 
FORTH FROM RUN TO RUN ON NORTHERN EXTENT OF HEAVIER QPF AXIS.
THERE WILL LIKELY BE A SHARP CUTOFF FROM SEVERAL INCHES OF
ACCUMULATING SNOW UNDER FRONTOGENETIC BANDING...AND QUICKLY
TAPERING TO A DUSTING TO THE NORTH (30 MILE RANGE). HAVE RELIED ON
AN ENSEMBLE APPROACH TO QPF...WITH 1/4 TO 3/4 INCH OF QPF ACROSS
THE REGION AS THE SYNOPTIC SETUP TAPS INTO A MOIST SW FLOW ALL THE
WAY FROM THE SUBTROPICAL PAC. ENSEMBLE INDICATING HIGHEST PROB OF
.5 INCHES OR GREATER AFTER TRANSITION TO SNOW FOR SOUTHERN
PORTIONS OF NYC/NJ METRO AND LI. 

MODELS IN GENERAL AGREEMENT WITH THERMAL PROFILES COOLING THROUGH 
THE OVERNIGHT...WITH A CHANGEOVER OF PRECIP FROM RAIN IN THE EARLY 
EVE TO WINTRY MIX THEN SNOW FROM NW TO SE. ALL AREAS APPEAR TO BE 
MAINLY SNOW BY 06Z. MODEST FRONTOGENETIC FORCING APPEARS TO WORK
INTO SOUTHERN ZONES...WITH POTENTIAL FOR SNOW TO BE HEAVY AT
TIMES LATE TONIGHT THROUGH THU MORNING THERE...COUPLED WITH STRONG
JET DYNAMICS. SNOW SHOULD GRADUALLY TAPER OFF IN INTENSITY AND
COVERAGE FROM NW TO SE THURSDAY AFTERNOON AS SHORTWAVE TROUGH
APPROACHES AND OFFSHORE STATIONARY FRONT SLIDES WELL OFFSHORE.

HIGHEST CONFIDENCE IN 6+ INCH AMOUNTS IS FOR LI AND SOUTHERN 
PORTIONS OF NYC/NJ METRO. WILL UPGRADE TO WARNING IN THIS AREA AFTER 
COLLAB WITH PHI AND BOX...FOR A 4 TO 8 INCH SNOWFALL. 00Z ENSEMBLE
RUNS HAVE REDUCED PROB OF 1/2 INCH QPF SLIGHTLY ACROSS SOUTHERN
AREAS...SO IF THIS TREND CONTINUES THIS ARE MAY FALL ON THE LOWER
END OF RANGE.

LOWER CONFIDENCE IN SNOWFALL FORECAST ACROSS SOUTHERN CT AND LOWER
HUDSON VALLEY...WITH POTENTIAL FOR SNOWFALL AMOUNTS TO RAPIDLY
DECREASE WORKING NORTHWARD. WITH LOW POTENTIAL FOR 6 INCHES FOR
COASTAL SOUTHERN CT...THE REST OF NE NJ...AND SOUTHERN PORTIONS OF
LOWER HUDSON VALLEY WILL LEAVE WATCH UP IN THIS AREA...BUT HIGHER
LIKELIHOOD OF ADVISORY LEVEL OR LOWER. FOR AREAS FAR N&W OF
NYC...BETWEEN A DUSTING TO 4 INCHES IS POSSIBLE...SO NOT ENOUGH
CONFIDENCE FOR AN ADVISORY AT THIS TIME.
 
DRYING CONDITIONS THURSDAY NIGHT...WITH TEMPS DROPPING INTO THE 
SINGLE DIGITS...LOWER TEENS NYC METRO...ON GUSTY NW WINDS. 
WINDCHILLS LIKELY DROPPING TO AROUND ZERO TO 5 BELOW ZERO FOR MUCH 
OF THE REGION BY FRIDAY MORNING.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THEREAFTER...MEAN TROUGHING CONTINUES INTO EARLY NEXT WEEK. 
UNSEASONABLY COLD CONDS (ABOUT 20 DEGREES BELOW SEASONABLE) CONTINUE 
THU NIGHT INTO FRI NIGHT AS CANADIAN HIGH PRESSURE BUILDS INTO THE 
REGION. 

THEN A SERIES OF WEAK SHORTWAVE/COLD FRONTS MOVE THROUGH THE 
REGION THIS WEEKEND INTO EARLY NEXT WEEK...WITH TEMPS MODERATING BUT 
STILL REMAINING SEVERAL DEGREES BELOW SEASONABLE. SOME LIGHT RA/SN 
SHOWER ACTIVITY POSSIBLE WITH ANY OF THESE DISTURBANCES.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
LOW PRESSURE TRACKS ACROSS EASTERN CANADA TODAY...WITH ITS TRAILING 
COLD FRONT CROSSING THE AREA LATE THIS EVENING.

PERIODS OF RAIN WITH GENERALLY MVFR VISIBILITY EXPECTED THROUGH THE 
DAY. CEILINGS PREDOMINATELY VFR UNTIL THIS EVENING.

COLD FRONT WILL TRACK THROUGH THE AREA LATE THIS EVENING AND STALL 
JUST S OF LONG ISLAND. RAIN WILL CHANGE BACK TO SNOW AROUND 06Z. 
HOWEVER...UNCERTAINTY REMAINS ON WHERE THE NORTHERN EDGE OF HEAVIER 
SNOW WILL BE TONIGHT.

SW FLOW EXPECTED TO PREVAIL UNTIL FROPA THIS EVE...BETWEEN 02Z AND
06Z...THEN BECOMING NW. GUSTS UP TO 20 KT POSSIBLE LATE. 

   ..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: HIGH CONFIDENCE IN MVFR VIS. VIS MAY BRIEFLY 
DROP TO IFR IN RAIN.

KLGA FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR VIS. VIS MAY BRIEFLY 
DROP TO IFR IN RAIN.

KEWR FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR VIS. VIS MAY BRIEFLY 
DROP TO IFR IN RAIN.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS MODERATE...WHICH 
IMPLIES SLANT RANGE VISIBILITY 4-6SM OUTSIDE OF CLOUD.

KTEB FCSTER COMMENTS: HIGH CONFIDENCE IN MVFR VIS. VIS MAY BRIEFLY 
DROP TO IFR IN RAIN.

KHPN FCSTER COMMENTS: HIGH CONFIDENCE IN IFR-MVFR VIS THROUGH THE 
DAY.

KISP FCSTER COMMENTS: HIGH CONFIDENCE IN IFR-MVFR VIS THROUGH THE 
DAY.

.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
.THURSDAY...-SN WITH IFR TO MVFR COASTAL TERMINALS...MVFR TO VFR
KSWF. N GUSTS TO 20 KT IN THE MORNING.
.THURSDAY NIGHT-FRIDAY...IMPROVING TO VFR THURS NIGHT. NW GUSTS 
15-20KT POSSIBLE THURSDAY NIGHT.
.SAT/SUN...VFR.

&&

.MARINE...
SCA CONDITIONS ARE EXPECTED TO CONTINUE ACROSS THE OCEAN WITH
OTHER WATERS REMAINING BELOW SCA. THE SCA EVENT WILL BE MORE OF A
MARGINAL ONE AND DUE MAINLY TO SEAS BUT ANY RAINFALL WILL BE OF HELP
TO TRANSPORT MOMENTUM DOWNWARD AND GIVE SOME HIGHER GUSTS THAT
WOULD REACH SCA THRESHOLDS. WATER TEMPS ARE A FEW DEGREES WARMER
ON THE OCEAN RELATIVE TO OTHER WATERS SO IT WILL BE RELATIVELY
EASIER FOR HIGHER GUSTS TO BE ACHIEVED ON THE OCEAN.

SMALL CRAFT ADVISORY CONDITIONS ARE LIKELY ON THE COASTAL OCEAN 
WATERS TONIGHT INTO THURSDAY MORNING AS A SERIES OF LOW PRESSURE
WAVES TRACKS TO THE SOUTH OF THE WATERS. SOME UNCERTAINTY IF SCA
CONDS CONTINUE INTO THU AFTERNOON...WITH HIGHER CONFIDENCE OF RE-
OCCURRENCE THU NIGHT. SO FOR NOW HAVE ONLY RUN SCA UNTIL THU
MORNING.

SUB SCA CONDS RETURN FRI AS HIGH PRESSURE BUILDS OVER THE WATERS.

A SERIES OF WEAK COLD FRONTS WILL MOVE THROUGH THE WATERS THIS 
WEEKEND INTO EARLY NEXT WEEK...ONE SATURDAY NIGHT INTO SUNDAY 
MORNING AND ANOTHER MONDAY NIGHT. WINDS APPROACH SCA CRITERIA 
SATURDAY INTO SATURDAY NIGHT AND THEN AGAIN MONDAY NIGHT INTO 
TUESDAY ON THE OCEAN WATERS...BUT AS OF RIGHT NOW...THEY SHOULD 
REMAIN BELOW. WAVES REMAIN BELOW SCA CRITERIA THROUGH THE PERIOD.

&&

.HYDROLOGY...
AROUND A QUARTER OF AN INCH OR LESS IS EXPECTED WITH THE RAINFALL
TODAY. LOW POTENTIAL FOR FLOODING ALTHOUGH SOME PONDING OF WATER
IS EXPECTED WITH STEADY MODERATE RAIN THAT FALLS DUE TO EXCESS
RUNOFF FROM MELTING SNOWPACK.

1/4 TO 3/4 INCH LIQUID EQUIVALENT PRECIPITATION IS LIKELY WEDNESDAY 
NIGHT INTO THURSDAY. MOST OF THIS WILL BE FROZEN...SO HYDROLOGIC 
IMPACTS ARE NOT EXPECTED.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER STORM WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY 
     EVENING FOR CTZ008>012.
NY...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST 
     THURSDAY FOR NYZ074-075-078>081-176>179.
     WINTER STORM WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY 
     EVENING FOR NYZ071>073.
NJ...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 PM EST 
     THURSDAY FOR NJZ107-108.
     WINTER STORM WATCH FROM 7 PM EST THIS EVENING THROUGH THURSDAY 
     EVENING FOR NJZ002-004-006-103>106.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST THURSDAY FOR ANZ350-353-
     355.

&&

$$
SYNOPSIS...JM/NV
NEAR TERM...JM/DS
SHORT TERM...NV
LONG TERM...JP
AVIATION...MMD
MARINE...JM/JP/NV
HYDROLOGY...JM/NV







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