Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 230349

Area Forecast Discussion
National Weather Service New York NY
1149 PM EDT Tue Aug 22 2017

A cold front approaches tonight and passes through Wednesday
morning. High pressure then dominates the weather pattern from
Wednesday afternoon into early next week.


Line of showers and thunderstorms have weakened across the area,
therefore, the Severe Thunderstorm Watch has been cancelled
for all counties. The chance for thunderstorms will continue
however over the next couple of hours with some gusty winds
possible and brief heavy rain. Otherwise, forecast is on track.

A pre-frontal trough and cold front move in from the west. Showers
and thunderstorms are expected with both boundaries. CAPE and shear
values are sufficient for strong storms with gusty winds. Some
of these storms may become severe, with damaging winds being the
main threat across Passaic, Orange, and Putnam counties and a
Severe Thunderstorm Watch has been issued until midnight tonight
for these areas. Better chances for the stronger gusts would be
along the pre- frontal trough as CAPE will be greater during
the evening hours. The trailing cold front will have less CAPE
to work with during the overnight hours, but winds aloft may
still allow for strong gusts.

The steering flow should be quick enough to mitigate chances of
flash flooding and training of cells is not expected to be a factor,
but with high moisture content around, minor nuisance/urbanized
flooding is possible.


The cold front will be right over the tri state area at the start of
Wednesday morning and should be east of Montauk by late morning.
Still cannot rule out a lingering shower or thunderstorm mainly east
of the city in the morning. Much drier air then filters in behind
the cold front for the afternoon with mostly sunny conditions. It
will start to feel less muggy as well, and highs will be in the
lower and mid 80s. Mainly clear for Wednesday night. Low
temperatures across the northernmost suburbs and the Pine Barrens
Region are expected to drop into the mid 50s.

There is a moderate rip current risk for Wednesday.


A mainly quiet weather pattern takes shape in the long term as
canadian high pressure will dominate with below normal temperatures
and mainly dry conditions.

Anomalous longwave trough will be swinging across the eastern states
on Thursday, with a vigorous piece of energy trailing behind the
main trough axis. This energy is progged to dive towards the region
Thursday night into early Friday morning at the same time of some
upper jet support. While ensemble members and deterministic runs are
dry with this feature, there is enough lift and brief moisture
return to warrant a low chance pop for showers. The shortwave energy
shifts offshore Friday morning, with the main upper trough lingering
just to the east through the weekend with tranquil conditions. The
surface high settles over the northeast for the weekend, then
centers itself off the New England coast early next week as ridging
builds aloft.

850 temperature anomalies will run 3-6C below normal into the
weekend. This will result in surface temperatures running several
degrees below normal. Forecast highs may be warmest on Thursday, in
the upper 70s and low 80s, and then run in the middle and upper 70s
through Sunday. A more easterly flow sets up early next week which
should help keep highs below normal. Nighttime temperatures will
range from the lower 50s inland to the lower 60s near the coast.


A cold front will move across the region tonight.

Area of showers and tstms has intensified across eastern PA past
2 hours, although most of the activity appears to be tracking N
of NYC terminals. There is a cluster in western NJ heading
towards NYC and if it holds together and develops into a line
would move through between 03-04z. Gusty winds and MVFR possible
in any stronger thunderstorm.

Low level jet increases through around 06Z, especially at the
coast, but with the loss of heating it will be difficult to mix
most of this down. Gusts in the 20s should continue at coastal

Shra/tstm activity is expected to weaken as it moves through
the area overnight. MVFR to IFR conds may redevelop/persist
especially at KBDR/KISP/KGON until cold fropa passes.

Northwest flow may be just strong enough to preclude seabreeze
development Wed aftn. Otherwise...VFR.

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

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/

KJFK TAF Comments: Best chc of tstms 03z-05z. Seabreeze
possible, but more unlikely to occur Wed aftn.

KLGA TAF Comments: Best chc of tstms 03z-05z.

KEWR TAF Comments: Best chc of tstms 03z-07z.

KTEB TAF Comments: Best chc of tstms 03z-07z.

KHPN TAF Comments: Best chc of tstms 04z-06z.

KISP TAF Comments: MVFR to IFR possibly redeveloping this eve
and persisting until late tonight.

.Wednesday night-Sunday...VFR.


A line of showers and thunderstorms will affect the western
and coastal zones, some of which could produce wind gusts of up
to 30 kt until about 1 am, mainly for NYC Harbor, the western
and central ocean zones, and the back bays. Thereafter, showers
and thunderstorms will weaken over the waters.

SCA remains on all waters for tonight. Extended the SCA on the ocean
waters until late morning/early afternoon Wednesday as seas at 5 ft
probably linger at least into Wednesday morning. Sub-SCA conditions
then for all waters by late Wednesday afternoon, lasting into the

Tranquil conditions and sub-SCA winds and seas are forecast on the
waters Thursday through the weekend as high pressure will be in


Showers and thunderstorms through tonight may cause minor
nuisance/urbanized flooding. No widespread hydrologic impacts are
forecast through the rest of the week.


Tides are running high astronomically. Water levels will
approach minor flood levels across mainly the south shore bays
areas with tonight`s high tide, but are likely to remain just


MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ330-335-
     Small Craft Advisory until 11 AM EDT Wednesday for ANZ353-355.
     Small Craft Advisory until 2 PM EDT Wednesday for ANZ350.


TIDES/COASTAL FLOODING... is the U.S. government's official web portal to all federal, state and local government web resources and services.