Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 030920
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
420 AM EST TUE MAR 3 2015

.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TODAY...GIVING WAY TO AN APPROACHING
WARM FRONT. THIS WARM FRONT WILL MOVE ACROSS WEDNESDAY MORNING
WITH A COLD FRONT APPROACHING DURING THE DAY. THE COLD FRONT
SLIDES TO THE SOUTHEAST WEDNESDAY NIGHT...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/...
CLOUDS WILL START TO MOVE IN FROM HIGH TO LOW AS HIGH PRESSURE
MOVES OFFSHORE. THE RETURN SOUTHERLY FLOW WILL COMMENCE THIS
AFTERNOON...BRINGING IN INCREASING MOISTURE INTO THE LOW LEVELS.

COLD ENOUGH AMBIENT TEMPERATURES WILL BE IN PLACE FOR SNOW TO
DEVELOP OUT AHEAD OF THE APPROACHING WARM FRONT. A LARGE FRACTION
OF THE WINTRY PRECIP WILL BE WITH THIS INITIAL ROUND MID TO LATE
AFTERNOON WITH THE SNOW.

HIGHS WERE TAKEN FROM NAM12 AND GMOS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
SNOW CONTINUES EARLY THIS EVENING AND THEN TRANSITIONS TO A WINTRY
MIX OF FREEZING RAIN AND SLEET BEFORE EVENTUALLY CHANGING TO PLAIN
RAIN. THIS PROGRESSION OCCURS SLOWLY FROM SOUTH TO NORTH AND WILL
BE DEPENDENT ON HOW FAST THE WARM FRONT MOVES THROUGH.
CLIMATOLOGICALLY...THE WARM FRONT WILL LIKELY MOVE SLOWER THAN
WHAT FORECAST MODELS SHOW.

THE TIMING OF THE ADVISORIES WILL BE THE SAME AS BEFORE BUT DID
EXTEND THROUGH EASTERN SUFFOLK AS THERE WILL BE A BRIEF WINDOW OF
LIGHT ICE ACCUMULATION EVEN THOUGH SNOW TOTALS THERE WILL BE ON
THE LOWER END AND AROUND 2 INCHES OR LESS.

MAINLY PLAIN RAIN EXPECTED WEDNESDAY WITH WARM FRONT PROGRESSING
NORTH OF THE REGION. HOWEVER...THERE COULD BE SOME LINGERING
FREEZING RAIN ESPECIALLY ACROSS THE INTERIOR WHERE THERE WOULD BE
BLOCKING OF THE SOUTHERLY FLOW NEAR AREAS OF HIGHER
TERRAIN...ALLOWING FOR VALLEYS TO TRAP SOME COLDER AIR AT THE
SURFACE.

MIN TEMPS TONIGHT LIKELY ACHIEVED EARLY IN THE EVENING AND THEN
SLOWLY RISING OVERNIGHT. THE TEMPS RISE WEDNESDAY AS WELL BUT RAIN
LINGERING THROUGH THE DAY WILL LIMIT THEIR POTENTIAL. AGAIN
GMOS AND NAM12 BLEND USED FOR TEMPERATURES.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS IN DECENT AGREEMENT WITH A COUPLE OF NORTHERN STREAM
SHORTWAVES PHASING AND DIGGING DOWN THE FRONT RANGE OF THE ROCKIES
INTO NORTHERN PLAINS EARLY THIS WEEK...INTERACTING WITH A SW US
LOW...AND THEN GRADUALLY LIFTING ACROSS THE US TO EAST COAST BY
THURSDAY NIGHT. SBU ENSEMBLE SENSITIVITY INDICATING THAT
ECMWF/CMC/GEFS ENSEMBLE MEANS ON FRONTAL PLACEMENT ARE IN GOOD
AGREEMENT FOR THE WED NIGHT THROUGH THU TIME PERIOD...WITH A
RELATIVELY LOW MEMBER SPREAD...WHICH CAN BE TRACED BACK TO
DIFFERENCES IN INTERACTION OF THE NORTHERN STREAM SHORTWAVE WITH SW
LOW.

HAVE STAYED CLOSE TO ENSEMBLE MEANS...WITH A STRONG COLD FRONT
MOVING SOUTH OF THE REGION WED EVE WITH FALLING TEMPS WED NIGHT. A
SERIES OF WAVES WILL DEVELOP ALONG THE COLD FRONT...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. MODELS CONTINUE TO SIGNAL POTENTIAL FOR 1/3 TO
1 INCH OF QPF ACROSS THE REGION AS THE SYNOPTIC SETUP TAPS INTO A
MOIST SW FLOW ALL THE WAY FROM THE SUBTROPICAL PAC.

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. NAM APPEARS TO BE OUTLIER WITH A WARM LAYER AT
700MB WHICH WOULD RESULT IN A PROLONGED PERIOD OF SLEET THROUGH THE
OVERNIGHT...PARTICULARLY ALONG THE COAST. THE SNOW COULD BE HEAVY AT
TIMES LATE WED NIGHT INTO THU MORNING BASED ON STRONG JET DYNAMICS
AND MODEST 850-700MB FRONTOGENETIC FORCING. LINGERING LIGHT SNOW
TAPERS OFF FROM NW TO SE THURSDAY AFTERNOON AS SHORTWAVE TROUGH
APPROACHES AND OFFSHORE STATIONARY FRONT SLIDES WELL OFFSHORE.

SO POTENTIAL CONTINUES TO EXIST FOR 6+ INCHES OF SNOW WED NIGHT INTO
THU...WITH THE BEST CHANCE OVER NYC/NE NJ/LONG ISLAND AND SE CT.

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...BUT
PREDICTABILITY IS LOW AT THIS POINT.

&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS OVERHEAD THIS MORNING...THEN MOVES EAST. A WARM
FRONT APPROACHES TONIGHT.

VFR WITH MID AND HIGH CLOUDS MOVING IN THIS MORNING. NW WINDS
CONTINUE TO DIMINISH BECOMING LIGHT AND VARIABLE BY 12Z WITH THE
HIGH MOVING OVERHEAD. THEN WINDS TURN TO THE SE BY AFTERNOON AT 5 TO
10 KTS.

BY LATE DAY...EXPECT CIGS TO LOWER TO MVFR IN LIGHT SNOW. IFR OR
LIFR EXPECTED TONIGHT...AFTER 23-00Z. MODERATE SNOW TRANSITIONS TO A
WINTRY MIX AS THE EVENING PROGRESSES.

   ..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: TIMING OF WIND SHIFT TO THE S AND ONSET OF
PCPN THIS AFTN MAY BE +/- 1-2 HOURS.

KLGA FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE S AND ONSET OF
PCPN THIS AFTN MAY BE +/- 1-2 HOURS.

KEWR FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE S AND ONSET OF
PCPN THIS AFTN MAY BE +/- 1-2 HOURS.

THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES  SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.

KTEB FCSTER COMMENTS: TIMING OF ONSET OF PCPN THIS AFTN MAY BE +/-
1-2 HOURS.

KHPN FCSTER COMMENTS: TIMING OF ONSET OF PCPN THIS AFTN MAY BE +/-
1-2 HOURS.

KISP FCSTER COMMENTS: TIMING OF ONSET OF PCPN THIS AFTN MAY BE +/-
1-2 HOURS.

.OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY...
.TONIGHT...IFR OR LOWER LIKELY. WINTRY MIX CHANGING OVER TO ALL RAIN
FROM SOUTHWEST TO NORTHEAST. LLWS LIKELY AFTER 06Z.
.WEDNESDAY...MVFR OR LOWER POSSIBLE IN LIGHT RAIN IN THE MORNING.
CONDITIONS MAY IMPROVE TO VFR IN THE AFTERNOON.
LLWS POSSIBLE IN THE MORNING.
.WEDNESDAY NIGHT-THURSDAY...MVFR OR LOWER POSSIBLE IN ANY
PRECIPITATION...WITH A TRANSITION BACK TO SNOW.
.THURSDAY NIGHT-FRIDAY...VFR. NW WINDS G15-20KT POSSIBLE THURSDAY
NIGHT.
.SATURDAY...VFR.

&&

.MARINE...
SCA CONDITIONS HAVE FALLEN FOR NOW AS PRESSURE GRADIENT RELAXES
WITH HIGH PRESSURE OVERHEAD. THE RETURN FLOW BEGINS LATER THIS
AFTERNOON AND CONTINUES THROUGH TONIGHT...BUILDING FETCH WILL LEAD
TO EVENTUAL RETURN OF SCA ACROSS THE OCEAN. SCA HOISTED FOR OCEAN
STARTING 02Z FOR EAST OF MORICHES INLET AND 05Z FOR REST OF OCEAN.
THIS CONTINUES THROUGH WEDNESDAY. WIND GUSTS MAY BE MORE LIMITED DUE
TO COLD WATERS AND WARMER AIR ALOFT BUT VERTICAL TRANSPORT WILL
ALLOW FOR THESE HIGHER WINDS TO 25-30 KT TO BE OCCASIONALLY MIXED
DOWN.

SMALL CRAFT ADVISORY CONDITIONS ARE LIKELY ON THE COASTAL OCEAN
WATERS FROM WEDNESDAY NIGHT AND THURSDAY...AND POSSIBLE THURSDAY
NIGHT AS A SERIES OF LOW PRESSURE WAVES TRACKS TO THE SOUTH OF THE
WATERS. SUB SCA CONDS RETURN FRI AS HIGH PRESSURE BUILDS OVER THE
WATERS.

A BRIEF PERIOD OF SCA CONDS POSSIBLE ON THE OCEAN WATERS SATURDAY IN
SW FLOW AHEAD OF A COLD FRONT.

ELSEWHERE...SUB-SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED FROM
WEDNESDAY NIGHT THOUGH SATURDAY.

&&

.HYDROLOGY...
AROUND A TOTAL 3/4 INCH OF LIQUID EXPECTED WITH THE UPCOMING EVENT
THIS AFTERNOON THROUGH WEDNESDAY. A LITTLE LESS THAN HALF OF IT
BEING IN FORM OF WINTER PRECIP.

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



&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM EST
     WEDNESDAY FOR CTZ005>008-011-012.
     WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM EST
     WEDNESDAY FOR CTZ009-010.
NY...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 2 AM EST
     WEDNESDAY FOR NYZ072>075-078>081-176>179.
     WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM EST
     WEDNESDAY FOR NYZ067>070.
     WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM EST
     WEDNESDAY FOR NYZ071.
NJ...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 2 AM EST
     WEDNESDAY FOR NJZ006-105>108.
     WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM EST
     WEDNESDAY FOR NJZ002-103.
     WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 6 AM EST
     WEDNESDAY FOR NJZ004-104.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM EST
     WEDNESDAY FOR ANZ353-355.
     SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EST
     WEDNESDAY FOR ANZ350.

&&

$$
SYNOPSIS...JM/NV
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...NV
AVIATION...24
MARINE...JM/NV
HYDROLOGY...JM/NV





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