NYC Office Forecast Discussion

141
FXUS61 KOKX 230539
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
139 AM EDT Wed Aug 23 2017

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

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
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.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
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.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
A cold front will move across the region tonight.

Most of the precipitation should be out of the city between
06-07Z. There may still be some left over showers, but the main
bulk of the precip will be over. Rain will end a few hours later
for the eastern terminals.

MVFR to IFR conds may redevelop/persist especially at
KBDR/KISP/KGON until cold front passes.

Winds will gradually shift from the West-Southwest to the
Northeast as the front comes through. Some gusts into the 20s
should continue at coastal terminals.

Northwest flow may be just strong enough to preclude seabreeze
development this afternoon. Otherwise...VFR.

.OUTLOOK FOR 06Z WEDNESDAY THROUGH SUNDAY...
.Wednesday night-Sunday...VFR.

&&

.MARINE...
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
night.

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

&&

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

&&

.TIDES/COASTAL FLOODING...
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
below.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT early this morning for
     ANZ330-335-338-340-345.
     Small Craft Advisory until 11 AM EDT this morning for ANZ353-
     355.
     Small Craft Advisory until 2 PM EDT this afternoon for ANZ350.

&&

$$
SYNOPSIS...JC/DS
NEAR TERM...JP
SHORT TERM...JC
LONG TERM...DS
AVIATION...BC
MARINE...JC/DS
HYDROLOGY...JC/DS
TIDES/COASTAL FLOODING...

NWS OKX Office Area Forecast Discussion