Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 300259
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
959 PM EST THU JAN 29 2015

.SYNOPSIS...
LOW PRESSURE AND AN ASSOCIATED COLD FRONT APPROACH FROM THE WEST
TONIGHT WITH THE COLD FRONT PASSING THROUGH LATE TONIGHT INTO
EARLY FRIDAY MORNING. AN ARCTIC COLD FRONT WILL FOLLOW FRIDAY
AFTERNOON AS THE LOW DEEPENS OFF THE NORTHEAST COAST. HIGH
PRESSURE BUILDS IN FRIDAY NIGHT AND SATURDAY.

A WINTRY PATTERN WILL PERSIST THROUGH THE MIDDLE OF NEXT
WEEK...WITH FRIGID COLD ON SATURDAY AND CHANCES FOR SNOW SUNDAY
NIGHT INTO MONDAY...AND AGAIN AROUND WEDNESDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
CLIPPER SYSTEM APPROACHES FROM THE WEST TONIGHT. A SHORTWAVE
EMBEDDED IN A DIGGING UPPER TROUGH WILL PROVIDE LIFT FOR PERIODS
OF LIGHT SNOW THROUGH THE OVERNIGHT. WARM ADVECTION AHEAD OF THE
LOW IS RAISING BOUNDARY LAYER TEMPERATURES...HOWEVER...PROFILE
STILL LOOKS COLD ENOUGH FOR ALL SNOW ON LAND. WARM AIR OVER THE
WATERS WILL ALLOW FOR RAIN AND SNOW AND A SLIGHT CHANCE THAT
ENOUGH WARM AIR MAY MOVE IN ACROSS THE VERY FAR EASTERN ZONES FOR
A MIX OF RAIN AND SNOW. TEMPERATURES WILL HOLD NEARLY STEADY OR
ONLY FALL A FEW DEGREES TONIGHT.

ADJUSTED POPS SLIGHTLY OVERNIGHT BASED ON LATEST TRENDS AND
GUIDANCE. NONE OF THE GUIDANCE IS CAPTURING THE RISE IN SFC TEMPS
WELL...BUT WOULD EXPECT THEM TO LEVEL OFF AND HOLD STEADY OR EVEN
SLIGHTLY FALL DUE TO EVAP COOLING.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
THE CLIPPER LOW MOVE THROUGH DURING THE MORNING WITH AN ASSOCIATED
COLD FRONT. MEANWHILE THE UPPER TROUGH CONTINUES TO DIG AND BECOME
NEGATIVELY TILTED. A STRONG VORT MAX ROUNDS THE BASE OF THE TROUGH
FRIDAY AFTERNOON ALLOWING FOR THE LOW TO RAPIDLY DEEPEN OFF THE
NORTHEAST COAST. AN ARCTIC FRONT MOVES THROUGH FRIDAY AFTERNOON AS
THE LOW DEEPENS. NORTHWEST WIND WILL INCREASE AND BECOME GUSTY AS
ARCTIC AIR FLOWS IN. LATE FRIDAY AFTERNOON AND FRIDAY NIGHT
SUSTAINED WIND AND GUSTS ARE EXPECTED TO FALL JUST BELOW ADVISORY
LEVELS...WITH THE HIGHEST WIND ALONG THE COAST. THE COMBINATION OF
COLD AIR AND GUSTY WIND WILL PRODUCE WIND CHILLS WELL BELOW ZERO
FRIDAY NIGHT...WITH WIND CHILLS AT ADVISORY LEVELS BY LATE FRIDAY
NIGHT. BEING LATE THIRD PERIOD INTO FOURTH PERIOD WILL HOLD OFF ON
A WIND CHILL ADVISORY.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
980S LOW SPINNING NEAR NOVA SCOTIA WILL KEEP GUSTY NW FLOW LOCKED IN
ON SAT...PRODUCING WIND CHILLS MAINLY AOB ZERO FOR MOST OF THE DAY.
AS WINDS SLACKEN LATE...WIND CHILLS WILL LIKELY RISE INTO THE SINGLE
DIGITS. H85 WINDS IN THE GFS ARE AROUND 55-60KT AT 12Z SAT...SO
THERE IS THE POTENTIAL FOR WIND ADVY EARLY WITH GUSTS IN THE 45-50
MPH RANGE. SUBSIDENCE ON THE WRN FRINGE OF THE SYS SHOULD AID IN THE
GUST POTENTIAL...WHILE AT THE SAME TIME CLEARING OUT THE SKIES.

WEAK HI PRES RIDGE SAT NGT SO MUCH LIGHTER WINDS INTO SUN.

MODELS LINING UP WITH THE NEXT SYS FOR SUN NGT AND MON. THE 12Z GFS
AND ECMWF ARE VIRTUALLY THE SAME WRT THE TRACK AND INTENSITY. AT 18Z
MON THE LOW CENTERS WERE APPROXIMATELY 60 MILES APART AND ABOUT 130
MILES S OF THE BENCHMARK. MOST OF THE GFS ENSEMBLE MEMBERS WERE
CLUSTERED ON THIS SOLN.

EXTENSIVE AREA OF MID LVL MOISTURE WITH THE SYS...SO WITH HIGH SLR/S
AT LEAST LGT-MDT ACCUMS POSSIBLE. BASED ON THE PROGRESSIVE
NATURE...IT LOOKS LIKE A 4-8 INCH POTENTIAL ATTM. THIS OF COURSE CAN
CHANGE...IN FACT A SRN TRACK COULD LEAVE THE CWA WITH JUST FLURRIES.
AS AN ASIDE...THE 12Z MEX HAS CAT 8 SNOWFALL FOR ALL SITES.

HI PRES MON NGT AND TUE. SUNNY ON TUE AS A RESULT.

THE GULF OPENS UP MIDWEEK POTENTIALLY IN TANDEM WITH ANOTHER NRN
STREAM UPR TROF. ECMWF PROGS LOW PRES HEADING TOWARDS CAPE COD. THIS
REFLECTS THE IDEA OF LOW PRES EXHIBITED IN THE 00Z RUN. THE GFS IS
LESS ORGANIZED. INCLUDED 30 POPS FOR PCPN WED.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
LOW PRESSURE APPROACHES FROM THE WEST TONIGHT...CROSSES THE AREA
FRIDAY MORNING...THEN EXITS TO THE EAST AS IT DEEPENS FRIDAY
AFTERNOON.

MVFR/IFR CONDITIONS DEVELOP IN PERIODS OF LIGHT SNOW BETWEEN 03Z AND
05Z FOR CITY TERMINALS...AND A COUPLE HOURS LATER FOR EASTERN
TERMINALS. STEADIEST SNOW LIKELY TOWARDS DAYBREAK AND MORNING FOR
CITY AND EASTERN TERMINALS WITH IFR CONDS. SNOW MAY BE BRIEFLY
MODERATE WITH LIFR CONDS.

CONDITIONS GRADUALLY IMPROVE TO MVFR FROM LATE MORNING TO EARLY
AFTERNOON...AND THEN VFR LATE AFTERNOON. ISOLATED SNOW
SHOWERS/FLURRIES POSSIBLE IN THE AFTERNOON.

GENERALLY EXPECTING 1-2 INCH SNOWFALL WITH HIGHEST AMOUNTS ACROSS
NORTHERN TERMINALS.

LIGHT S WINDS OVERNIGHT...ALTHOUGH A BRIEF PERIOD OF OCCASIONAL S
GUSTS TO 20 KT POSSIBLE AT COASTAL TERMINALS THROUGH ABOUT 06Z.

WINDS SHIFT SW-W-NW FRIDAY MORNING...WITH NW WIND GUSTS TO 25-35 KT
AFTERNOON.

.OUTLOOK FOR 00Z FRIDAY NIGHT THROUGH TUESDAY...

.FRIDAY NIGHT-SATURDAY...VFR. NW WINDS G30-35 KT LIKELY. A FEW 40
KT GUSTS POSSIBLE.
.SATURDAY NIGHT...VFR. NW WIND G 20-30KT POSSIBLE EARLY.
.SUNDAY...VFR. NW WIND G15-20KT POSSIBLE. .SUNDAY NIGHT-
MONDAY..CHANCE OF SNOW WITH IFR CONDITIONS. NE-N WIND G25-35KT
POSSIBLE.
.MONDAY NIGHT...BECOMING VFR FROM W TO E AS ANY SNOW COMES TO AN
END. N-NW WIND G20-25KT POSSIBLE.
.TUESDAY...VFR.

&&

.MARINE...
LOW PRESSURE APPROACHES FROM THE WEST TONIGHT WITH AN INCREASING
SOUTHERLY FLOW ALLOWING FOR SEAS ON THE OCEAN TO BUILD TO SMALL
CRAFT LEVELS OVERNIGHT. IN ADDITION SOME SOUTHERLY WIND
GUSTS...MAINLY OVER THE OUTER FORECAST WATERS...MAY REACH SMALL
CRAFT LEVELS. AS LOW PRESSURE PASSES THROUGH THE WATERS LATE
TONIGHT INTO EARLY FRIDAY THE WIND WILL DIMINISH AND WILL LIKELY
FALL BELOW SMALL CRAFT FOR A FEW HOURS. THEN AS THE LOW AND
ASSOCIATED COLD FRONT MOVE THROUGH WIND SHIFTS TO THE NORTHWEST
AND INCREASE AS THE LOW DEEPENS. AN ARCTIC COLD FRONT CROSSES
FRIDAY AFTERNOON. THE DEEPENING LOW AND STRONG COLD ADVECTION WILL
ALLOW THE WIND OVER THE WATERS TO GUST TO GALE FORCE FRIDAY
AFTERNOON INTO SATURDAY. THE SMALL CRAFT ADVISORY REMAINS AS
POSTED...AND THE GALE WARNING WAS EXTENDED THROUGH SATURDAY.

GALES WILL WIND DOWN SAT NGT AS LOW PRES PASSES N OF NOVA SCOTIA.
SEAS MAY BE CLOSE TO 5 FT ON THE EXTREME ERN OCEAN SUN...ELSEWHERE
WINDS AND WAVES WILL BE BLW SCA LVLS. SCA WINDS LIKELY MON AS LOW
PRES DEEPENS E OF THE WATERS. IMPROVING COND ON TUE AS HI PRES
BUILDS OVER THE REGION.

&&

.HYDROLOGY...
ONE TO TWO TENTHS OF AN INCH OF LIQUID EQUIVALENT IS EXPECTED FROM
LATE TONIGHT INTO FRIDAY AFTERNOON WITH THE PRECIPITATION FALLING
AS SNOW.

LOW PRES SUN NGT AND MON WILL BRING THE POTENTIAL FOR LESS THAN AN
INCH OF LIQUID EQUIVALENT. PCPN LIKELY TO BE ALL SNOW.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...GALE WARNING FROM 1 PM FRIDAY TO 6 PM EST SATURDAY FOR ANZ330-
     335-338-340-345-350-353-355.
     SMALL CRAFT ADVISORY FROM 1 AM TO 1 PM EST FRIDAY FOR ANZ350-
     353-355.

&&

$$




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