Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 210826
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
426 AM EDT Mon Aug 21 2017

.SYNOPSIS...
High pressure moves across the region this morning and offshore
this afternoon. High pressure moves farther offshore tonight. A
cold front approaches from the west Tuesday into Tuesday night.
This cold front will move across the region on Wednesday. A
much drier and cooler airmass will move into the region for the
end of the week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
High pressure moves across the region this morning and offshore
this afternoon. Expecting a mainly dry day with just a slight
chance of showers and thunderstorms for far western Orange
County late this afternoon. 850mb temperatures forecast to reach
near 15-16 degrees C. Surface temperatures forecast to reach
several degrees warmer than yesterday. Mid 80s to near 90
degrees F for much of the region with mostly sunny conditions
for most locations.

The sky cover forecast still contains some uncertainty for the
times of the partial solar eclipse, which should run from about
120 PM to 400 PM in NYC and peak at 244 PM. This deals with how
much cirrus moves in as forecast models show some convection in
PA developing as well as the sea breeze convergence and
resulting cu field and how expansive that gets.

Like previous forecast, a look at the HRRRX conveys a slight
decrease during maximum obscuration of sun during eclipse, so
adjusted temperature a degree downward at 19Z (3PM local time).

There is a low risk of rip currents today, becoming moderate
late today at Atlantic beaches.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...

Rest of the forecast shows high pressure moving farther offshore
and a cold front gradually approaching from the west.
Continually more warm and humid conditions are expected.
Forecast has warmer temperatures Tuesday, getting hot and humid
for quite a few locations. Could see heat indices up to 100
degrees in and around NYC.

Precip forecast remains near or below 30 percent for showers and
thunderstorms. Not much forcing but increasing instability and
possible lee trough forming Tuesday could provide focus for
convergence. Models are pretty minimal with forecast rainfall
amounts overall tonight through Tuesday.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A cold front approaches the region Tuesday night and pushes across
the forecast area on Wednesday. Expect cloud cover to increase and
showers and thunderstorms to develop and move across the region
through this time frame. By Wednesday evening, skies will begin to
clear and a much cooler airmass will be arriving.

Canadian high pressure builds into the region Thursday through the
weekend, providing dry and sunny conditions. Temperatures will
remain below normal as highs only reach the 70s to near 80 each day.

The dry and cooler conditions are expected to continue into
Monday.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR through the TAF period as high pressure remains in control.

Isolated shra/tsra possible late evening for NYC/NJ and NW
terminals.

SW winds will increase this morning into the afternoon, with
southerly sea breeze development at coastal terminals. Gusts of
15 to 20 kt likely this afternoon. SW winds diminish to less
than 10 kt this evening.

...NY Metro Enhanced Aviation Weather Support...

Detailed information, including hourly TAF wind component forecasts,
can be found at: http://www.weather.gov/zny/n90

KJFK TAF Comments: S gusts to 20 kt possible for early evening
push. Low prob of shra/tsra aft 01z.

The afternoon KJFK haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KLGA TAF Comments: S gusts to 20 kt possible for late aft/early
evening push. Low prob of shra/tsra aft 01z.

The afternoon KLGA haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KEWR TAF Comments: Low prob of SE sea breeze btwn 20-24z. Low
prob of shra/tsra aft 01z. SW gusts 15 to 20 kt possible in the
afternoon.

The afternoon KEWR haze potential forecast is GREEN...which implies
slant range visibility 7SM or greater outside of cloud.

KTEB TAF Comments: Moderate prob of of S sea breeze btwn
20-24z. Low prob of shra/tsra aft 01z. SW gusts 15 to 20 kt
possible in the afternoon.

KHPN TAF Comments: Low prob of shra/tsra aft 00z.

KISP TAF Comments: SSW gusts 15 to 20 kt possible late
afternoon.

.OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY...
.Late Tonight...VFR. Isolated shower/tsra possible. Low chance
MVFR or lower stratus/fog at eastern terminals.
.Tuesday-Tuesday Night...Isolated aft shra/tsra. Chance of more
widespread showers and thunderstorms with MVFR or lower Tuesday
Night into early Wed morning. VFR SW winds G15-20KT Tuesday
afternoon.
.Wednesday...Becoming VFR in the morning with NW gusts 15-20 kt.
.Wednesday Night-Friday...VFR.

&&

.MARINE...
Starting off with quiet conditions on the waters well below SCA
thresholds with the high pressure area building in. The high
traverses over the waters this morning and moves offshore this
afternoon. The increasing return southerly flow will lead to
building seas late with ocean seas according to NWPS reaching
near 3 ft by the end of today. Winds gusts maximize near 20 kt
late today into early this evening. Ocean seas remain mostly 3
ft tonight into early Tuesday with winds slightly subsiding and
then these both increase Tuesday afternoon with SCA conditions
coming into place by mid to late afternoon on the ocean. The
southerly fetch by that timeframe builds the oceans seas up to
near 5 ft.

Small Craft Conditions continue Tuesday night into Wednesday as
winds and seas remain high with the approach and passage of a cold
front. For now, a Small Craft advisory is in effect for the ocean
waters through Tuesday night. it is likely the SCA will  need to be
expanded to the non-ocean waters. Also, SCA conditions will likely
continue into Wednesday.

Conditions fall below SCA levels late Wednesday into Wednesday
night. Winds and seas are then forecast to remain, in the absence of
any increased swell, below SCA levels through the weekend.

&&

.HYDROLOGY...
No widespread hydrologic impacts are forecast through the week.

&&

.TIDES/COASTAL FLOODING...
Tides are running high astronomically. For South Shore Bays,
there is the potential for some water levels to just reach the
minor coastal flooding benchmarks for this afternoon and Tuesday
afternoon as the onshore flow increases.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 3 PM Tuesday to 6 AM EDT Wednesday
     for ANZ350-353-355.

&&

$$
SYNOPSIS...BC/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...BC
AVIATION...NV
MARINE...BC/JM
HYDROLOGY...BC/JM
TIDES/COASTAL FLOODING...



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