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Area Forecast Discussion
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000
FXUS61 KOKX 012055
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
455 PM EDT MON SEP 1 2014

.SYNOPSIS...
WEAK HIGH PRESSURE REMAINS OVER THE REGION TONIGHT IN THE WAKE OF A 
SURFACE TROUGH. A COLD FRONT THEN APPROACHES DURING TUESDAY BEFORE 
PASSING THROUGH TUESDAY NIGHT. HIGH PRESSURE BUILDS IN FOR THE LATTER 
HALF OF THE WEEK. ANOTHER COLD FRONT WILL IMPACT THE REGION THIS
WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
ISO/SCT CONVECTION DIMINISHES THIS EVENING FROM THE COMBINATION OF 
ATMOSPHERIC STABILIZATION...LOSS OF MOISTURE CONVERGENCE DUE TO
DISSIPATING SURFACE TROUGH AND SEABREEZE BOUNDARIES...AND UPPER
LIFT SHIFTING EAST OUT OF THE AREA. PWAT VALUES WILL STILL BE ON
THE HIGH SIDE...SO HEAVY DOWNPOURS REMAIN POSSIBLE IN ANY
SHOWERS/TSTMS.

DRY WEATHER BY AROUND MIDNIGHT...BUT REMAINING MUGGY AS DEWPOINTS 
HOVER AROUND 70. PATCHY LIGHT FOG PROBABLY DEVELOPS OVERNIGHT AS 
WELL.

THERE IS A MODERATE RISK OF RIP CURRENTS INTO THIS EVENING.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
COLD FRONT APPROACHES DURING THE DAY TUESDAY. A PRE-FRONTAL TROUGH 
AHEAD OF IT DEVELOPS NEAR OUR WESTERN ZONES. SHOWER/TSTM THREAT 
BEGINS IN THE AFTERNOON ALONG THIS TROUGH...AND ENDS FOR MOST SPOTS 
OVERNIGHT WHEN THE TRAILING COLD FRONT PASSES THROUGH. CAPPED POPS 
IN THE CHC CATEGORY. PARAMETERS DURING THE AFTERNOON AND EARLY 
EVENING SUPPORT THE POTENTIAL OF THUNDERSTORMS WITH STRONG WIND 
GUSTS. LARGE HAIL WOULD BE LESS OF POSSIBILITY DUE TO RELATIVELY 
HIGH WBZ/FREEZING LEVEL HEIGHTS. TSTM STRENGTH DIMINISHES AFTER 
EARLY EVENING WITH LESS CAPE IN SPITE OF BETTER LIFT FROM THE 
PASSING COLD FRONT. PWATS STILL RATHER HIGH...SO HEAVY DOWNPOURS 
POSSIBLE IN ANY SHOWER.

ABOVE NORMAL TEMPERATURES WITH MUGGY CONDITIONS CONTINUE THROUGH 
THIS PERIOD. WITH 850MB TEMPS OF 17-18C...PARTLY TO MOSTLY SUNNY 
CONDITIONS FOR MOST OF THE DAY AND A SW FLOW...EXPECTING PARTS OF NE 
NJ TO REACH INTO THE LOW-MID 90S...WITH LOW 90S IN THE CITY AND A 
GOOD PORTION OF THE LOWER HUDSON VALLEY. MOST OTHER SPOTS EXPECTED 
TO END UP AT 85-90. REGARDING HEAT ADVISORY CONCERNS IN THE 
CITY...ALTHOUGH IT APPEARS THAT A DECENT PORTION OF THE CITY WILL 
REACH A HEAT INDEX OF AT LEAST 95 FOR AN HOUR OR TWO TOMORROW 
AFTERNOON...INDICES HAD FAILED TO REACH 95 MONDAY AFTERNOON. NO 
ADVISORIES WILL THEREFORE BE POSTED AS PER LOCAL POLICY.

THERE IS A MODERATE RISK OF RIP CURRENTS ON TUESDAY.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
COLD FRONT OFFSHORE WILL CONTINUE TO PUSH EAST ON WEDNESDAY AS HIGH 
PRESSURE BUILDS IN. DRY CONDITIONS ARE EXPECTED THROUGH FRIDAY AS 
THE CENTER OF THE HIGH MOVES OVER THE REGION AND OFF THE EAST COAST 
BY THURSDAY WHILE ALOFT THERE WILL BE A RATHER ZONAL PATTERN. 
HUMIDITY LEVELS DURING THIS PERIOD WILL EASE UP A BIT AS DEWPOINTS 
DROP TO THE LOWER 60S ON WEDNESDAY...WITH SOME UPPER 50S DEWPOINTS 
POSSIBLE ON THURSDAY. HOWEVER...THEY CREEP BACK UP TOWARDS THE LOWER 
AND MIDDLE 60S AGAIN ON FRIDAY ON THE RETURN FLOW WITH THE HIGH 
OFFSHORE. 

A COLD FRONT WILL APPROACH THE AREA FRIDAY NIGHT INTO 
SATURDAY...PUSHING OFFSHORE SOMETIME SATURDAY NIGHT. THERE IS SOME 
MODEL CONSENSUS ON PUSHING THE COLD FRONT OFFSHORE SATURDAY 
NIGHT...BUT THERE ARE DIFFERENCES THEREAFTER. THE 00Z ECMWF STALLS 
THE FRONT JUST OFFSHORE AND THERE WOULD BE A CHANCE FOR POST-FRONTAL 
RAIN THROUGH SUNDAY NIGHT. THE 12Z GFS AND CMC KEEP THE SYSTEM 
PROGRESSIVE...ENDING THE RAIN SATURDAY NIGHT...KEEPING SUNDAY DRY. 
GFS ENSEMBLE MEAN IS ACTUALLY MORE PROGRESSIVE WITH THE COLD 
FRONT...PUSHING IT OFFSHORE DURING THE DAY SATURDAY...BUT ALSO ENDS 
IT SATURDAY NIGHT. ALSO...MODELS DIFFER IN DEVELOPMENT AND PLACEMENT 
OF LOW PRESSURE ALONG THE FRONTAL BOUNDARY...WHICH LEAD TO LARGE 
DIFFERENCES IN PLACEMENT OF ANY HEAVY RAINFALL. ALTHOUGH THE GFS IS 
MORE PROGRESSIVE...THE FRONT HAS SLOWED DOWN SIGNIFICANTLY FROM THE 
PREVIOUS 06Z RUN. SO...GIVEN UNCERTAINTY WILL KEEP AT LEAST SLIGHT 
CHANCE POPS IN FOR SUNDAY MORNING...DRYING OUT BY THE AFTERNOON. 

TEMPERATURES WILL BE ABOVE NORMAL THROUGH SATURDAY. 
THEREAFTER...BELOW NORMAL TEMPERATURES EXPECTED AS A CONTINENTAL 
POLAR AIRMASS BUILDS IN.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
A SURFACE TROUGH WILL WEAKEN AS IT MOVES EAST TONIGHT. A COLD FRONT 
APPROACHES LATE TUESDAY.

WIDELY SCATTERED SHRA/TSTM ACTIVITY WILL CONTINUE TO DEVELOP OFF
THE SEABREEZE BOUNDARIES AND HIGHER ELEVATIONS THROUGH AROUND
23-00Z...BUT LIKELY WEAKEN AS THEY DRIFT EASTWARD. OTHERWISE...VFR
LATE THIS AFTERNOON WITH SCATTERED TO BROKEN CU.

BY TONIGHT...PATCHY STRATUS AND FOG IS EXPECTED...ESPECIALLY LATER 
ON AT NIGHT. MVFR OR IFR POSSIBLE...ESPECIALLY OUTSIDE OF NYC
METRO TERMINALS.

VFR TUESDAY MORNING AS ANY MORNING STRATUS AND FOG BURNS OFF.

SOUTH TO SOUTHWEST WINDS LIGHTEN TONIGHT. SOUTHWEST WIND PERSISTS
TUESDAY MORNING...GENERALLY UNDER 10 KTS.

     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: POSSIBLE AMENDMENTS FOR SCATTERED SHOWERS/ 
THUNDERSTORMS THROUGH 23Z OR SO.

KLGA FCSTER COMMENTS: POSSIBLE AMENDMENTS FOR SCATTERED SHOWERS/ 
THUNDERSTORMS THROUGH 23Z OR SO.

KEWR FCSTER COMMENTS: SEABREEZE BOUNDARY IS JUST WEST OF THE
AIRPORT...RESULTING IN 150-170 WINDS. THIS BOUNDARY MAY WAVER
ACROSS THE AIRPORT THROUGH AROUND 23Z...BEFORE WINDS RETURN TO
LIGHT SW. POSSIBLE AMENDMENTS FOR AN ISOLATED SHOWERS/THUNDERSTORMS
THROUGH 23Z OR SO.

KTEB FCSTER COMMENTS: POSSIBLE AMENDMENTS FOR AN ISOLATED
SHOWERS/THUNDERSTORMS THROUGH 23Z OR SO.

KHPN FCSTER COMMENTS: POSSIBLE AMENDMENTS FOR AN ISOLATED
SHOWERS/THUNDERSTORMS THROUGH 23Z OR SO.

KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

.OUTLOOK FOR 18Z TUE THROUGH FRI...
.TUE AFTERNOON-TUE NIGHT...MAINLY VFR EXCEPT FOR SCATTERED LATE  
AFTERNOON AND NIGHTTIME SHRA/TSRA. 
.WED-FRI NIGHT...VFR CONDITIONS ARE EXPECTED.
.SAT...SUB VFR POSSIBLE IN SCATTERED SHRA/TSRA.

&&

.MARINE...
SUB-SCA CONDITIONS EXPECTED ON THE WATERS THROUGH THE FORECAST 
PERIOD WITH A RELATIVELY WEAK PRESSURE GRADIENT MOST OF THE TIME. 
THERE COULD BE SHOWERS AND TSTMS TUESDAY NIGHT...AND AGAIN LATE 
FRIDAY INTO SATURDAY AS A FRONT APPROACHES.

&&

.HYDROLOGY...
ISOLATED/SCT SHOWERS AND TSTMS INTO THIS EVENING SHOULD BE 
SHORT-LIVED. LOCALIZED MINOR URBANIZED/SMALL STREAM FLOODING WOULD 
BE POSSIBLE. FLASH FLOODING THREAT LOOKS TO BE LOW. 

ISO/SCT SHOWERS/TSTMS LATE TUESDAY/TUES NIGHT WOULD LIKELY RESULT IN 
NO MORE THAT LOCALIZED MINOR URBANIZED/SMALL STREAM FLOODING.

NO HYDROLOGIC ISSUES EXPECTED WEDNESDAY THROUGH THE WEEKEND.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...JC/JP
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...JP
AVIATION...NV/PW
MARINE...JC/JP
HYDROLOGY...JC/JP






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