Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 301132
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
732 AM EDT TUE SEP 30 2014

.SYNOPSIS...
A BACK DOOR COLD FRONT WILL SLOWLY MOVE THROUGH THIS MORNING.
MULTIPLE UPPER LEVEL DISTURBANCES WILL THEN AFFECT THE AREA
THROUGH MID WEEK...FOLLOWED BY HIGH PRESSURE BUILDING FROM THE
NORTH THURSDAY INTO FRIDAY. A COLD FRONT WILL PASS THROUGH ON
SATURDAY...FOLLOWED BY HIGH PRESSURE BUILDING IN ON SUNDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SHORTWAVE WITH ASSOCIATED VORT MAX MOVING THROUGH THE REGION THIS
MORNING...CONTINUING TO TRIGGER LIGHT RAIN WITH PATCHY DRIZZLE OVER
LONG ISLAND...NYC AND SOUTHERN CT. VERY MOIST LOWER LVLS RESULTING
IN AREAS OF FOG....WITH PATCHY DENSE FOG...OVER AREAS OUTSIDE OF NYC
METRO. HAVE ADDED TO FORECAST THROUGH MID MORNING AND ISSUED AN
SPS TO ADDRESS THE SUDDEN VIS CHANGES.

LOW LEVEL FLOW TURNS TO E-NE IN THE WAKE OF A PASSING BACK DOOR
COLD FRONT THIS MORNING. AS THE FRONT CONTINUES TO PUSH SLOWLY
WSW-WARD AND A WEAK UPPER TROUGH MOVES ACROSS...SHOULD SEE MORE
SHOWERS TODAY ESPECIALLY AS THE COMBO OF DAYTIME SFC HEATING AND
MID LEVEL COOLING VIA THE UPPER TROUGH INCREASES INSTABILITY. NAM
SOUNDINGS SHOW SCAPE OF UP TO 500 J/KG...ENOUGH TO HELP GENERATE
SHOWERS BUT NOT THUNDER WITH THE INSTABILITY CONFINED MOSTLY BELOW
THE FREEZING LEVEL. FCST LIKELY POP MAINLY FOR LONG ISLAND...WITH
CHANCE ELSEWHERE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
SCT TO NUMEROUS SHOWERS SHOULD CONTINUE TO BE AROUND TONIGHT INTO
WED AS AN UPPER LOW APPROACHES FROM THE WEST...THEN MOVES ACROSS
ON WED. THE UPPER LOW WILL INTERACT WITH A DEVELOPING INVERTED
TROUGH EXTENDING NW-WARD FROM OFFSHORE LOW PRESSURE ON WED...
WITH POTENTIAL FOR LOCALLY HEAVIER RAIN OF OVER AN INCH NEAR AND
JUST EAST OF WHERE THIS INTERACTION OCCURS...WHICH IS STILL
UNCERTAIN DUE TO ITS MESOSCALE NATURE. THE 00Z NAM/GFS AND 29/12Z
ECMWF WERE POINTING TOWARD SE CT AND ERN LONG ISLAND...WHILE THE
00Z ECMWF/03Z SREF ARE FARTHER EAST.

CLOUDY SKIES AND AND E-NE FLOW OF MARITIME AIR WILL PERSIST...WITH
TEMPS A COUPLE OF DEG ABOVE AVG TODAY...THEN NEAR OR SLIGHTLY
BELOW AVG ON WED.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
LINGERING CHC FOR PCPN WED EVENING...MAINLY OVER EASTERN AREAS...AS
STRONG UPR LVL SHORTWAVE CLOSES OFF AND PUSHES EAST. 00Z MODEL
SUITE IN GENERAL AGREEMENT WITH RAIN SHOWERS ENDING OVER AREAS WEST
OF NYC BY 06Z...AND THEN EASTERN AREAS BY THURS MORNING. WHILE A
BRIEF HEAVY DOWNPOUR IS NOT OUT OF THE QUESTION WED EVENING...THE
TREND WITH THE MODELS HAS TO PUSH IT EAST...MOST LIKELY OCCURRING
OUTSIDE THE CWA. DRY CONDITIONS THEN SETTING UP THRU THURS NIGHT-FRI
WITH SFC HIGH DIPPING SOUTH BETWEEN TWO SFC LOW PRESSURE
SYSTEMS...AND RIDGING ALOFT.

ATTENTION THEN TURNS TO AN APPROACHING LOW PRESSURE SYSTEM FOR THE
FIRST HALF OF THE WEEKEND. SLIGHT DISCREPANCIES WITH 00Z MODELS WITH
GFS THE FASTEST SOLUTION AND ECMWF THE SLOWEST. HOWEVER...IT SHOULD
BE NOTED ALL MODELS ARE NOW TRENDING FASTER FOR THE PROGRESSION.
DEPENDING ON THE STRENGTH OF THE RIDGING...THE MODELS COULD BE
WEAKENING IT TOO QUICKLY AND THUS BRINGING THE FRONT AND ASSOCIATED
PCPN THROUGH QUICKLY AS WELL. AS SUCH...SLIGHTLY ADJUSTED THE TIMING
OF THE PCPN FRI NIGHT-SAT...BUT DID NOT WANT TO DEVIATE TOO MUCH FROM
PRIOR FORECAST UNTIL A GOOD HANDLE OF THE TREND CAN BE MADE.
CONFIDENCE EXISTS IT WILL RAIN ON SATURDAY...FIGURING OUT THE TIMING
WILL NEED TO BE IRONED OUT IN SUBSEQUENT FORECASTS. DRY WX ON
FRIDAY...THEN BEGAN POPS AFTER 00Z SAT WITH THE PASSING OF A WEAK
SHORTWAVE OUT AHEAD OF THE MAIN UPR LVL LOW. HAVE LIKELY POPS IN BY
12Z SAT MORNING AND THEN TAPER POPS OFF WEST TO EAST SAT NIGHT AS
MAIN FORCING ALOFT SWINGS THROUGH THE NORTHEAST.

SFC HIGH BUILDS IN THE WAKE OF THE FRONT SUNDAY-MONDAY WHILE THE
REGION REMAINS UNDER BROAD TROUGHING. HAVE DRY WX IN FOR SUN-MON
WITH THE NEXT CHC OF PCPN COMING BY MON NIGHT.

NEAR SEASONAL TEMPS IN PLACE THRU SAT. A BRIEF BURST OF CAA BEHIND
THE FRONT WILL SEND TEMPS DOWN A DEGREES BELOW NORMAL FOR SAT
NIGHT-SUN NIGHT. HOWEVER...RETURN FLOW QUICKLY SETS UP WITH THE HIGH
PRESSURE BUILDING IN...PUSHING TEMPS BACK TO NEAR NORMAL BY MONDAY.

&&

.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
A COLD FRONT IS SLIDING SOUTH ACROSS THE NY METRO THIS MORNING.
THE FRONT SAGS SOUTH OF THE REGION THIS MORNING AS HIGH PRESSURE
BUILDS OVER NEW ENGLAND.

IFR CIGS ARE LOCATED BEHIND THE FRONT. THESE ARE NOW INTO KLGA AND
KISP AS OF 11Z. EXPECTING SLOW IMPROVEMENT BY MID MORNING FROM EAST
TO WEST...THOUGH UNSURE OF TIMING DETAILS AND RATE OF IMPROVEMENT.

FAIRLY CONFIDENT THAT WE`LL BE VFR IN THE AFTERNOON WITH WESTERN
SECTIONS THE LAST TO IMPROVE.

SOME LIGHT RAIN WITH SCATTERED SHOWERS POSSIBLE EASTERN SECTIONS
TODAY.

     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)

JFK FCSTER COMMENTS: UNCERTAINTY IN CIG HEIGHT THIS AM WITH IFR
POSSIBLE AROUND 13Z. HIGH CONFIDENCE IN EAST SFC WIND LESS THAN 10
FOR AFTN.

KLGA FCSTER COMMENTS: EXPECT GRADUAL RAISING OF THE CIG THIS
MORNING. HIGH CONFIDENCE IN SFC WIND FCST.

KEWR FCSTER COMMENTS: UNCERTAINTY IN ARRIVAL TIME OF MVFR CIG THIS
AM.

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

KTEB FCSTER COMMENTS: UNCERTAINTY IN CIG HEIGHT THIS AM.

KHPN FCSTER COMMENTS: CONFIDENT IN THE IMPROVEMENT THIS
MORNING...THOUGH UNCERTAINTY IN THE TIMING.

KISP FCSTER COMMENTS: TIMING OF CIG IMPROVEMENT COULD BE +/- 1-2
HOURS.

.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
.LATE T0NIGHT...MVFR OR LOWER CIGS POSSIBLE. CHC -SHRA E-NE WINDS
AROUND 10 KT.
.WED...MVFR LOCALLY IFR CIGS/VSBYS/-SHRA. E-NE WINDS 10-15 WITH G
20 KT ALONG THE COAST.
.THU...CHC MVFR MAINLY AM. NE WINDS AROUND 10 KT.
.FRI...VFR. SE-S WINDS AROUND 10 KT.
.SAT...RAIN LIKELY - MVFR OR LOWER IN THE AM. SW WINDS AM BECMG WNW
PM. GUSTS 20-25KT LIKELY LATE.

&&

.MARINE...
INCREASING E-NE FLOW IN THE WAKE OF A BACK DOOR COLD FROPA...AS
THE WATERS BECOME SANDWICHED BETWEEN HIGH PRESSURE TO THE NORTH
AND DEVELOPING OFFSHORE LOW PRESSURE...SHOULD LEAD TO SCA CONDS
TONIGHT INTO WED NIGHT...AND POSSIBLY THU. SCA REMAINS FOR LATE
THIS EVENING THROUGH WED AFTERNOON AS FLOW INCREASES TO 20-25 KT
AND SEAS BUILD TO 3-5 FT BY LATE EVENING...AND TO 4-7 FT ON WED.

GENERALLY EXPECTING SUB-SCA CONDITIONS ON ALL NON-OCEAN WATERS
THROUGH THE COMING WEEKEND. FOR THE OCEAN WATERS...OCNL GUSTS UP
TO 25 KT WILL BE PSBL WED NIGHT INTO THU...WITH THE WINDS
DIMINISHING AS HIGH PRESSURE BUILDS IN THU. COULD SEE ANOTHER CHC
FOR 25 KT GUSTS RIGHT AHEAD OF THE FRONT FRI NIGHT-SAT...THEN
SUNDAY WITH CAA OVER THE WATERS. SEAS BUILDING IN RESPONSE TO
INCREASED WINDS MID WEEK...EXPECTING 4-6 FT SEAS THRU THU BEFORE
SUBSIDING WITH THE DIMINISHING WINDS. SEAS WILL BUILD TO 5-7 FT
FOR THE WEEKEND BEFORE DROPPING TO LESS THAN 5 FT ONCE AGAIN
ON SUNDAY.

&&

.HYDROLOGY...
NO SIGNIFICANT PCPN EXPECTED THROUGH TUE NIGHT. A FEW TENTHS OF
AN INCH OF RAINFALL...AND LOCALLY UP TO AN INCH...ARE POSSIBLE
WED-WED NGT...MAINLY SE CT AND ERN LONG ISLAND. BETWEEN ONE HALF
TO ONE INCH OF RAIN IS ALSO POSSIBLE WITH COLD FROPA
FRI NIGHT-SAT.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 6 PM EDT
     WEDNESDAY FOR ANZ350-353-355.

&&

$$
SYNOPSIS...GOODMAN/SEARS
NEAR TERM...GOODMAN
SHORT TERM...GOODMAN
LONG TERM...SEARS
AVIATION...TONGUE
MARINE...GOODMAN/SEARS
HYDROLOGY...GOODMAN/SEARS







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