National Weather Service Raw Text Product

831 
FXUS61 KOKX 201755
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1255 PM EST WED JAN 20 2016

.SYNOPSIS...
WEAK HIGH PRESSURE REMAINS WEST OF THE AREA THIS AFTERNOON AS AN
UPPER LEVEL DISTURBANCE APPROACHES FROM THE WEST AND MOVES
THROUGH OVERNIGHT. CANADIAN HIGH PRESSURE GRADUALLY BUILDS INTO
THE REGION THURSDAY THROUGH EARLY FRIDAY. A POTENTIAL SIGNIFICANT
NOR'EASTER COULD IMPACT THE AREA FOR THE WEEKEND. HIGH PRESSURE
BUILDS IN LATE SUNDAY THROUGH MONDAY NIGHT. A COLD FRONT APPROACHES
FROM THE WEST ON TUESDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RAISED HIGHS JUST A COUPLE OF DEGREES BASED ON LATEST OBS/TRENDS.

SHORTWAVE RIDGING ALOFT BUILDS ACROSS THE AREA TODAY AS WEAK
SURFACE HIGH PRESSURE BUILDS TOWARDS THE REGION. MID AND HIGH
LEVEL CLOUDS WORK IN FROM THE WEST THIS AFTERNOON AHEAD OF
AN APPROACHING SHORTWAVE.

TEMPS WILL BE MODERATED FROM THE LAST COUPLE OF DAYS AS THE ARCTIC
AIRMASS CONTINUES TO MODIFY. HIGHS SHOULD GENERALLY RANGE FROM
THE MID TO UPPER 30S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
A SHORTWAVE APPROACHING THE NORTHERN GREAT LAKES THIS MORNING
WILL APPROACH THE REGION THIS EVENING AND THEN MOVES ACROSS
TONIGHT. AT THE SURFACE...AN ASSOCIATED COLD FRONT WILL MOVE
ACROSS THE REGION THIS EVENING WITH A RE-INFORCING SHOT OF CAA.
WITH LIMITED MOISTURE AND DEEP WESTERLY FLOW...NOT EXPECTING MUCH
IN THE WAY OF PRECIP WITH THIS FRONT...BUT CANT RULE OUT A FEW
FLURRIES OR AN ISOLATED SNOW SHOWER THIS EVENING INTO TONIGHT AS
THE FRONT AND SHORTWAVE PASS. BETTER CHANCE FOR SOME LIGHT SNOW
LOOKS TO BE ACROSS THE MID ATLANTIC WITH SOME SOUTHERN STREAM
SUPPORT.

THE SHORTWAVE MOVES EAST THURSDAY...WITH CONFLUENT FLOW ALOFT
SUPPORTING CANADIAN HIGH PRESSURE/S GRADUALLY BUILDING INTO THE
REGION THROUGH FRIDAY. DRY CONDITIONS EXPECTED THU THRU FRI WITH A
BREEZY NW FLOW. FEW-SCT CU POTENTIAL ON THU...PARTICULARLY NW OF
NYC...WITH WEAK SHORTWAVE ENERGY MOVING THROUGH INTERACTING WITH
RESIDUAL MOISTURE FROM LAKE STREAMERS. INCREASING HIGH CLOUDS FRI
AFT AHEAD OF DEVELOPING COASTAL STORM.  

TEMPS WILL GENERALLY RUN SEVERAL DEGREES BELOW SEASONABLE THU AND
FRI...IN THE UPPER 20S TO LOWER 30S. GOOD RADIATIONAL COOLING
CONDS POSSIBLE ACROSS FAR OUTLYING AREAS THU NIGHT...WITH LOWS
WELL DOWN IN THE TEENS. ELSEWHERE LOWS IN THE UPPER TEENS TO LOWER
20S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
POTENTIAL FOR A SIGNIFICANT NOR'EASTER STORM CONTINUES FOR FRIDAY
NIGHT INTO SATURDAY NIGHT.

MODELS IN GOOD AGREEMENT WITH A NOR'EASTER TO AFFECT THE
REGION DURING THIS TIME PERIOD...BUT THERE ARE TIMING AND PTYPE
ISSUES THAT WILL HOPEFULLY BE IRONED OUT NOW THAT THE STORM SYSTEM
THAT WILL EVENTUALLY BECOME THE NOR'EASTER HAS MOVED INTO THE
PACIFIC NORTHWEST AND INTO IDAHO AND MONTANA.

HIGHLY AMPLIFIED UPPER LEVEL PATTERN AS UPPER LEVEL SHORTWAVE
DEVELOPS INTO A CLOSED LOW OVER THE SOUTHERN U.S. AND TRACKS EAST
FRIDAY NIGHT...ALLOWING THE SURFACE LOW TO STRENGTHEN AS IT MOVES
TOWARD THE SOUTHEAST COAST OF THE U.S. AS THE LOW REACHES THE
SOUTHEAST COAST...IT WILL TURN NORTHEAST...PARALLELING THE U.S.
COAST LATE FRIDAY NIGHT INTO SATURDAY. IT THEN MAKES SLOW
PROGRESSION NORTH...THEN NORTHEAST AS IT DEVELOPS INTO A DOUBLE
BARRELED LOW SATURDAY NIGHT INTO SUNDAY. IT THEN TREKS EAST OF THE
40/70 BENCHMARK ON SUNDAY. 

AS FAR AS THE OPERATIONAL MODELS ARE CONCERNED...THE 00Z GFS AND
CANADIAN ARE SIMILAR IN TIMING WITH THE ONSET OF THE PRECIPITATION
LATE FRIDAY NIGHT. THE 00Z ECMWF IS ABOUT 6 HOURS BEHIND. THE
CANADIAN IS THE QUICKEST TO MOVE THE PRECIPITATION OUT...WHILE THE
GFS AND ECMWF ARE FAIRLY SIMILAR.

THE TOUGHEST PART OF THE FORECAST WILL BE THE PRECIPITATION TYPE.
THE GFS AND THE ECMWF DO HINT AT WARMER AIR ALOFT AND AT THE SURFACE
WORKING ITS WAY FROM EAST TO WEST. GIVEN THE UNCERTAINTY AT THIS
TIME...DID NOT MAKE TOO MUCH IN THE WAY OF CHANGES TO WHAT WAS IN
THE PREVIOUS FORECAST. RIGHT NOW...THINKING IS THAT THE RAIN WILL AT
LEAST MIX IN OVER THE TWIN FORKS. HOWEVER...A CHANGEOVER TO ALL RAIN
IS A POSSIBILITY FOR LONG ISLAND FOR A PERIOD OF TIME...ESPECIALLY
GIVEN THE WARM OCEAN TEMPERATURES. 

FINALLY...PRECIPITATION AMOUNTS ARE ALSO UNCERTAIN. A 1 TO 2 INCH
LIQUID EQUIVALENT IS NOT OUT OF THE QUESTION. HOWEVER...THE ECMWF
DOES HAVE A SHARP PRECIPITATION GRADIENT WHICH IS OFTEN THE CASE
WITH THESE SYSTEMS...WHICH THE GFS DOES NOT SHOW. SNOW AMOUNTS WILL
DEPEND ON THE LIQUID EQUIVALENT AMOUNTS...AND HOW MUCH WARM AIR
MAKES ITS WAY UP HERE AND ALLOWS ANY MIX OR CHANGEOVER TO RAIN.
STORM TOTAL SNOW ONLY GOES OUT TO THROUGH SATURDAY. BY NIGHTFALL ON
SATURDAY...GENERALLY...THERE COULD BE 6-8 INCHES OF SNOW FROM
PORTIONS OF NE NJ...NYC...LONG ISLAND AND SE CT. LESSER AMOUNTS AS
YOU GO INLAND AS THERE WILL BE LESS PRECIPITATION HERE...AND LESSER
AMOUNTS OVER THE TWIN FORKS DUE TO MIXING. 

THIS STILL A VERY UNCERTAIN FORECAST. THE ONLY THING WE CAN BE
FAIRLY CERTAIN OF IS THAT IT WILL PRECIPITATE AND IT WILL BE WINDY.
WIND GUSTS SATURDAY AFTERNOON TO 50 MPH IS NOT OUT OF THE QUESTION.
COASTAL FLOODING WILL ALSO BE AN ISSUE WITH THE FULL MOON. SEE THE
COASTAL FLOODING SECTION FOR MORE DETAILS.

DEEP LAYERED RIDGING BUILDS IN SUNDAY NIGHT-MONDAY...THEN SLIDES TO
THE EAST MONDAY NIGHT. ASSOCIATED SUBSIDENCE SHOULD KEEP THINGS DRY
IN THIS TIME FRAME. A 700-500 HPA TROUGH APPROACHES ON TUESDAY.
GFS/ECMWF HAVE DIFFERENCES IN DETAILS ON WHAT HAPPENS AHEAD OF IT ON
TUESDAY OVER THE REGION...SO HAVE KEPT POPS TO SLIGHT CHANCE FOR NOW.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE BUILDS IN FROM THE WEST.

VFR TODAY AND THIS EVENING. CHC FLURRIES TOWARDS MIDNIGHT TONIGHT. 

NW WINDS AROUND 10KT DIM 5-10KT THIS EVENING. SEE COMMENTS ABOUT
GUSTS.

...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: WINDS MOSTLY SOUTH OF 310 MAGNETIC. OCCASIONAL
GUSTS 17-20 KT POSSIBLE BEFORE 19Z.

KLGA FCSTER COMMENTS: WINDS MOSTLY SOUTH OF 310 MAGNETIC.
OCCASIONAL GUSTS 17-20 KT POSSIBLE BEFORE 19Z.

KEWR FCSTER COMMENTS: WINDS MOSTLY SOUTH OF 310 MAGNETIC.
OCCASIONAL GUSTS 17-20 KT POSSIBLE BEFORE 19Z.

KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

KHPN FCSTER COMMENTS: OCCASIONAL GUSTS 17-20 KT POSSIBLE BEFORE 19Z.

KISP FCSTER COMMENTS: OCCASIONAL GUSTS 17-20 KT POSSIBLE BEFORE 19Z.

.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
.THURSDAY AND THURSDAY NIGHT...VFR.
.FRIDAY...VFR.
.FRIDAY NIGHT...CHC SUB-VFR AND SNOW LATE. NE GUSTS 25KT LATE.
.SAT/SAT NIGHT...SNOW DEVELOPING BY LATE MORNING...POSSIBLY BECOMING
HEAVY AT TIMES WITH IFR AND LOWER CONDITIONS. NE WINDS AT 20-30 KT
WITH 40-50 KT GUSTS.
.SUNDAY...CHC SUB-VFR AND SNOW AM. VFR PM. N GUSTS 25-30KT.
.MONDAY...VFR.

&&

.MARINE...
SCA CONDITIONS CONTINUE ACROSS THE EASTERN OCEAN WATERS BUT WILL
COME TO AN END BY LATE AFTERNOON.

A PERSISTENT NW FLOW WILL CONTINUE OVER THE WATERS TONIGHT THROUGH
FRIDAY BETWEEN HIGH PRESSURE TO THE WEST AND CUTOFF LOW PRESSURE
OVER NE CANADA. GENERALLY SUB SCA CONDITIONS EXPECTED DURING THIS
TIME...BUT POTENTIAL FOR MARGINAL SCA CONDS ON OCEAN WATERS
THURSDAY INTO THU NIGHT AS GRADIENT TIGHTENS AND LAPSE RATES
STEEPEN.

THEREAFTER...POTENTIAL NOR'EASTER IMPACTS THE WATERS FRI NIGHT
INTO SUN. WAVES WILL BUILD DURING THE DAY SATURDAY TO UPWARDS OF
20 FT ON THE OCEAN WATERS AS A NOR'EASTER IMPACTS THE COASTAL
WATERS. ELSEWHERE...5 TO 8 FT ARE NOT OUT OF THE QUESTION ACROSS
THE CENTRAL AND EASTERN SOUND AND GARDINER'S BAY. 5 FT WAVES ARE
POSSIBLE IN THE BACK BAYS...AND NY HARBOR. AS FAR AS WINDS...STORM
FORCE WINDS ARE POSSIBLE SATURDAY AND SATURDAY NIGHT WITH WINDS
AND WAVES DIMINISHING LATE SATURDAY NIGHT THROUGH SUNDAY.

&&

.HYDROLOGY...
NO MEASURABLE PRECIP EXPECTED TONIGHT-THURSDAY NIGHT...AND QUITE
LIKELY THROUGH FRIDAY.

THERE IS THE POTENTIAL FOR MORE THAN AN INCH OF LIQUID EQUIVALENT
LATE FRIDAY INTO SATURDAY NIGHT. LESSER AMOUNTS ARE
POSSIBLE...DEPENDING ON THE TRACK OF THE NOR'EASTER. FOR NOW...THE
PRECIPITATION IS FORECAST TO BE MAINLY IN THE FORM OF HEAVY
SNOWFALL. NO HYDROLOGIC PROBLEMS ARE ANTICIPATED.

&&

.TIDES/COASTAL FLOODING...
A POTENTIAL NOR'EASTER COULD PRODUCE MULTIPLE EPISODES OF COASTAL
FLOODING AROUND THE TIMES OF HIGH TIDE SAT INTO SUN. THE TIDES OF
PRIMARY CONCERN WILL BE SAT MORNING AND SAT NIGHT...WITH POTENTIAL
GALE TO STORM FORCE NE WINDS PILING WATER ALONG THE COAST.

POSITIVE TIDAL DEPARTURES OF 1 1/2 TO 2 FT ARE NEEDED FOR MINOR
COASTAL FLOODING AND 2 1/4 TO 3 FT FOR MODERATE COASTAL FLOODING
WITH THE SAT MORNING HIGH TIDE. AVAILABLE TIDAL GUIDANCE (BASED ON
GFS) IS INDICATING POTENTIAL FOR 2 TO 3 1/2 FT OF SURGE DURING THIS
TIME PERIOD...WHICH WOULD SIGNAL POTENTIAL FOR MODERATE COASTAL
FLOODING. FOR THE SAT EVENING HIGH TIDE...POSITIVE TIDAL DEPARTURES
OF 2 TO 2 1/2 FT OR SURGE ARE NEEDED FOR MINOR COASTAL FLOODING AND
3 TO 4 FT FOR MODERATE COASTAL FLOODING. IF NE GALE TO STORM FORCE
WINDS CONTINUE UNTIL THE TIME OF HIGH TIDE...POTENTIAL EXISTS FOR
MODERATE COASTAL FLOOD ONCE AGAIN. THE MOST VULNERABLE TO
MODERATE COASTAL FLOODING WOULD BE ALONG WESTERN/CENTRAL HALF OF
LI SOUND AND SOUTHERN BAYS OF WESTERN LI AND NYC...AND
TRADITIONALLY VULNERABLE PORTIONS OF NY HARBOR. FOR THE SUNDAY
MORNING HIGH TIDE THE SURGE SHOULD BE LOWERING DUE TO WINDS
TURNING NORTHERLY...BUT POTENTIAL FOR ANOTHER ROUND OF AT LEAST
MINOR COASTAL FLOODING EXISTS.
 
BASED ON SPREAD IN MODEL GUIDANCE ON TRACK AND INTENSITY OF THIS
COMPLEX NOR'EASTER...AND THEREFORE STRENGTH AND DIRECTION OF WIND
FIELDS...CONFIDENCE IS ONLY MODERATE IN THE SURGE RANGE AT THIS
TIME. SOME THINGS TO KEEP IN MIND...THE TENDENCY IS FOR MODELS TO
UNDERESTIMATE THE NORTHWARD BACKING OF WINDS OF INTENSIFYING
NOR'EASTERS TRACKING TO THE SE OF LI...WHICH IN TURN ACTS TO
REDUCE SURGE ALONG THE TRI-STATE AREA. ALSO...LOOKING BACK AT
SURGE FROM THE TOP 3 STORM ANALOGS AS ANALYZED BY SAINT LOUIS
UNIVERSITY CIPS PAGE (JAN 7-8 1996, MAR 3 1994, AND DEC
2010)...BETWEEN 2 1/2 TO 4 FT OF SURGE WERE EXPERIENCED WITH THOSE
PARTICULAR STORMS. THIS SURGE RANGE MATCHES FAIRLY WELL WITH
CURRENT SURGE FORECASTS...BUT PAST RESULTS DO NOT GUARANTEE FUTURE
FORECASTS...SO MONITOR THE LATEST FORECASTS.

IN ADDITION TO SURGE POTENTIAL...AN EASTERLY SWEEP OF 8 TO 12 FT
SURF WILL BRING POTENTIAL FOR DUNE TOE EROSION ALONG ALL ATLANTIC
OCEAN BEACHES AND POTENTIAL FOR LOCALIZED DUNE OVERWASHES FOR THE
BARRIER BEACHES FROM FIRE ISLAND AND POINTS WEST ON SATURDAY. THIS
IS BASED ON USGS COASTAL CHANGE HAZARDS MODELING FOR A GALE FORCE
NOR-EASTER.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ330-
     340-353-355.
     SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ350.

&&

$$

SYNOPSIS...JP/NV/DW
NEAR TERM...NV/DW
SHORT TERM...NV
LONG TERM...JP
AVIATION...JC
MARINE...JP/NV/DW
HYDROLOGY...JP/NV
TIDES/COASTAL FLOODING...NV