Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 211444
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1044 AM EDT THU AUG 21 2014

.SYNOPSIS...
HIGH PRESSURE REMAINS CENTERED TO THE NORTH AND EAST OF THE AREA
THROUGH TONIGHT. MEANWHILE...WAVES OF LOW PRESSURE ALOFT MOVE
ACROSS THE REGION TODAY AND TONIGHT. AN UPPER LEVEL DISTURBANCE
WILL TRACK THROUGH THE AREA ON FRIDAY AS HIGH PRESSURE BUILDS DOWN
FROM EASTERN CANADA. THE HIGH WILL CONTINUE TO BUILD SOUTHWARD
INTO THE REGION ON SATURDAY...AND REMAIN ANCHORED OVER THE AREA
THROUGH THE BEGINNING OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ISO-SCT SHOWERS MAINLY NORTH/WEST OF NYC METRO WITH A STRAY TSTM
PSBL THROUGH THIS AFTN AS AN UPPER LVL TROUGH PIVOTS THROUGH THE
REGION. SLIGHTLY ADJUST POPS THROUGH EARLY AFTN WITH 14Z RADAR
REFLECTIVITY SHOWING MOST OF THE PCPN NORTH OF THE AREA. MESO
MODELS STILL SHOWING DEVELOPMENT MAINLY OVER WESTERN AREAS THIS
AFTN AFTR 18Z WHERE THE BEST INSTABILITY CAN BE
EXPECTED...GENERALLY AROUND 1000 J/KG. ONSHORE FLOW OVER EASTERN
AREAS/ALONG THE COAST WILL MAINTAIN A MORE STABLE ATMO...RESULTING
IN MOSTLY DRY CONDITIONS TILL THIS EVENING. FLOW ALOFT LESS THAN
10 KTS...SO WHILE FLASH FLOODING IS NOT A BIG CONCERN...THERE IS
THE POTENTIAL FOR A BRIEF PERIOD OF HEAVY RAINFALL WITH THE SLOW
MOVING CELLS. WITH A LACK OF A SIGNIFICANT LIFTING MECHANISM...NOT
LOOKING FOR ANYTHING STRONG OR SEVERE.

CLOUD COVER WILL HELP TO KEEP TEMPERATURES SLIGHTLY BELOW NORMAL
FOR THE MOST PART. GENERALLY HIGHS WILL BE IN THE UPPER 70S TO
LOWER 80S. TEMPS ARE THUS FAR ON TRACK FOR THE DAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
THE CHANCE FOR SHOWERS CONTINUES TONIGHT AS THE CLOSED UPPER LOW
ASSOCIATED WITH THE TROUGH MOVES INTO NEW ENGLAND AND A SHORTWAVE
MOVES AROUND ITS BASE. WITH THE LOSS OF DAYTIME
HEATING...THE CHANCE FOR THUNDERSTORMS DECREASES...AND THUS JUST
PLAIN SHOWERS ARE IN THE FORECAST. SOUTHWESTERLY FLOW OFF THE
OCEAN EARLY TONIGHT WILL ALLOW FOR A MOIST AIRMASS. DEWPOINTS
WILL RISE INTO THE MIDDLE 60S. WINDS SHIFT MORE TO THE NORTHEAST
LATE TONIGHT...AND DEWPOINTS WILL COME BACK DOWN TO THE LOWER 60S
BY DAYBREAK FRIDAY. THIS NORTHEASTERLY FLOW WILL THEN MEAN AN EVEN
COOLER DAY ON FRIDAY AS COMPARED TO THURSDAY...WITH HIGHS
GENERALLY IN THE LOWER TO MIDDLE 70S. SOME UPPER 70S FOR THE NYC
METRO REGION.

HIGH PRESSURE FROM THE NORTHEAST WILL NOSE INTO THE AREA
FRIDAY...ALLOWING THE CHANCES FOR SHOWERS TO END FROM EAST TO
WEST ON FRIDAY.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
SOLID MODEL CONSENSUS THRU TUE. HIPRES BUILDS INTO THE AREA THEN
STRENGTHENS AS THE UPR RIDGE TRANSLATES EWD. ON WED...THE ECMWF
BRINGS A CDFNT CLOSE...BUT THE GFS KEEPS THE FEATURE OFF THE LOCAL
MAP. HAVE SIDED WITH THE SLOWER GFS SOLN AS THIS FITS A FAST MODEL
BIAS AT THIS TIME RANGE.

A MARITIME POLAR AIRMASS IS LOCKED IN FRI NGT INTO THE FIRST PART OF
SAT. VIRTUALLY NO LIFT IN THE MOIST LAYER...SO HAVE ONLY FCST
SPRINKLES. THE CLOUDS BEGIN TO CLR IN THE AFTN FROM NE TO SW AS
STRONG SUBSIDENCE KICKS IN.

DRY WITH LGT WINDS SUN-WED COURTESY OF THE HIGH. SOME CIRRUS AT
TIMES.

TEMPS BLW NORMAL SAT...THEN A GRADUAL WARMING TREND TAKES PLACE
SUN-TUE AS HEIGHTS INCREASE.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
WEAK HIGH PRESSURE REMAINS OVER THE AREA.

GENERALLY EXPECT VFR CONDITIONS THROUGH THE AFTERNOON HOURS. THERE
WILL BE ISOLATED TO SCATTERED SHOWERS...AND ANY SHOWER COULD REDUCE
CEILINGS OR VSBYS TO MVFR BRIEFLY. BEST CHANCE FOR SHOWERS ACROSS
NYC METRO AND NORTH AND WEST...LATER IN THE DAY.

POSSIBLE HIGHER COVERAGE OF SHOWERS TONIGHT AS AN UPPER LEVEL
DISTURBANCE MOVES THROUGH. BEST CHANCE NYC METRO AND NORTH AND WEST.
VFR CEILINGS AND VSBYS MAY LOWER TO MVFR OR EVEN IFR LATE AT NIGHT.

LIGHT WINDS WILL EVENTUALLY BECOME SOUTHEAST OR SOUTH 5 TO 10 KTS
THIS AFTERNOON. WINDS TONIGHT SHOULD LIGHTEN AS THEY TURN TO THE
EAST.

     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: LIGHT AND VARIABLE WINDS WILL BECOME SOUTHEAST
THIS AFTERNOON.

KLGA FCSTER COMMENTS: LIGHT AND VARIABLE WINDS ARE EXPECTED TO
BECOME SOUTHEAST THIS AFTERNOON. TIMING COULD BE OFF AN HOUR OR
TWO.

KEWR FCSTER COMMENTS: LIGHT WINDS BECOME SOUTHEAST...JUST TO
THE RIGHT OF 130 MAGNETIC.

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

KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED.

.OUTLOOK FOR 12Z FRI THROUGH MON...
.FRI MORNING...SUB VFR POSSIBLE IN LOW CLOUDS AND FOG.
.FRI AFTERNOON-MON...VFR.

&&

.MARINE...
WINDS AND SEAS FORECAST ON TRACK FOR TODAY. THERE WILL BE A
CHANCE FOR SHOWERS TODAY AS AN UPPER LEVEL DISTURBANCE MOVES
TOWARD THE AREA. AN ISOLATED THUNDERSTORM IS POSSIBLE ACROSS THE
WESTERN SOUND AND HARBOR. WINDS AND SEAS SHOULD REMAIN BELOW SCA
CRITERIA...BUT MAY APPROACH SCA CRITERIA BRIEFLY IN ANY
THUNDERSTORM. THE CHANCES FOR SHOWERS CONTINUE INTO TONIGHT AND
FRIDAY...WITH CHANCES DIMINISHING THROUGHOUT THE DAY FRIDAY. WINDS
AND WAVES CONTINUE TO REMAIN BELOW SCA FOR TONIGHT AND FRIDAY.

WINDS WILL APPROACH SCA LVLS FRI NGT...THEN DIMINISH DURING THE DAY
ON SAT. SEAS ON THE OCEAN WILL BUILD TO AROUND 4 FT LATE FRI
NGT...THEN LINGER THRU MOST OF SAT BEFORE SUBSIDING. A SCA MAY BE
NEEDED ESPECIALLY ON THE OCEAN FRI NGT AND SAT. OTHERWISE...WINDS
AND SEAS WILL BE BLW SCA LVLS SUN-AT LEAST TUE.

&&

.HYDROLOGY...
A FEW SLOW MOVING THUNDERSTORMS ARE POSSIBLE TODAY ACROSS THE
LOWER HUDSON VALLEY AND INTERIOR NE NJ AND INTO NYC. THESE STORMS WILL
HAVE THE POTENTIAL TO PRODUCE LOCALLY HEAVY RAIN...BUT BASIN
AVERAGED TOTALS ARE FORECAST TO REMAIN LIGHT WITH THE ISOLATED
NATURE OF THE STORMS. TRACE AMOUNTS OF PCPN ARE POSSIBLE FRI NGT INTO
SAT. IT WILL THEN REMAIN DRY THRU THE BEGINNING OF NEXT WEEK.

&&

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

&&

$$
SYNOPSIS...JMC/JP
NEAR TERM...JMC/JP/SEARS
SHORT TERM...JP
LONG TERM...JMC
AVIATION...IRD
MARINE...JMC/JP/SEARS
HYDROLOGY...JMC/JP





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