discussion on 2023-09-13

000
FXUS61 KOKX 140118
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
918 PM EDT Wed Sep 13 2023

.SYNOPSIS...
-- Changed Discussion --A cold front will pass to the east of the area by the early
morning hours. High pressure then builds in on Thursday, remaining
centered to the north and west through Friday, before weakening
over the weekend. At the same time, Hurricane Lee is forecast to
pass offshore to our east. A weak frontal system impacts the
region early next week.

Monitor https:/www.weather.gov/okx/tropical or
https:/www.nhc.noaa.gov for the latest NHC forecasts on
Hurricane Lee.-- End Changed Discussion --

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --Flood Watch for SE CT has been dropped with this update. There
is no longer a threat of flash flooding.

The cold front just east of NYC and the Lower Hudson Valley will
work slowly east and pass offshore during the early morning
hours. An isolated shower is still possible this evening.

Drying conditions with more northerly flow eventually settles
into the region from west to east late tonight. Dewpoints are
lowering into the 60s. The drier air has considerably decreased
the coverage of convection.

Some cold air advection can be expected late tonight. Lower
temperatures for the lows compared to recent nights, mainly
ranging from the low 50s to low 60s by daybreak Thursday.-- End Changed Discussion --

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Dry conditions expected Thursday through Thursday night with
near normal temperatures.

On Thursday, upper level heights will rise, with a weakening
upper level trough. The trough moves north with most energy as
conveyed by mid level positive vorticity advection. The back end
of the trough approaches. At the surface, the cold front will
move well out into Atlantic with high pressure starting to build
into the local area from the north and west. The high pressure
area will be centered across the Great Lakes.

On Thursday night, upper level heights are more steady, showing
a weakened trough axis along the back end that will be moving
in. At the surface, high pressure will continue to build in
partially but will remain centered across the interior parts of
the Northeast and across the Eastern Great Lakes.

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Not much change in the long term period and stuck fairly close to
the NBM/official forecast.

On Friday, high clouds start to move into the area in advance of
Lee. Temperatures will be in the upper 60s and lower 70s. Northerly
winds between inland high pressure and Lee will also be on the
increase to 15G25mph as the pressure gradient increases between
inland high pressure and the outer circulation of Lee.

The strongest winds associated with Lee are expected to arrive
Friday night and continue into Saturday, with winds backing NW on
Sat as the hurricane passes well east. The hurricane`s wind field
will be expanding in size as it moves northward, and winds
especially across coastal SE CT and eastern Long Island could become
strong, sustained 25-30 mph with gusts up to 40 mph possible. Can`t
rule out tropical storm force winds in those areas right near the
shoreline in areas with a good NW-N exposure.

NBM still bringing some POPs to portions of eastern Long Island and
CT on the periphery of Lee, with only light rainfall amounts
expected.

Lee lifts to the north with mainly dry conditions on Sunday. A cold
front and upper level shortwave will move across the region on
Monday, which may result in a slight chance or isolated shower or
two. Dry conditions return for the middle of the week.

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
A cold front just east of the NYC and the Lower Hudson Valley
terminals this evening will track slowly east and offshore
during the early morning hours. High pressure centered over the
Great Lakes will then build slowly east through Thursday.

Mainly VFR. A spotty shower cannot be ruled out this evening.

Light and variable winds ahead of the front and light WNW
winds behind it will become NNW overnight and strengthen to
5-10kt. This flow continues on Thursday 10-13 kt with G15-20kt.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Timing of wind shifts this evening may be off by 1-2 hours.

Gusts on Thursday may be more occasional than frequent.

OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...

Thursday Afternoon: VFR. N-NW gusts 15-20 kt.

Thursday Night-Friday Night. VFR. N-NNE wind gusts around 20-25
possible, strongest Friday night.

Saturday: VFR. NW wind gusts around 20-25 kt for NYC metro, western
Long Island and western CT. NW gusts 25-35 kt possible eastern Long
Island and southeast CT.

Sunday-Monday: VFR.

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

.MARINE...
Small craft advisory remains in effect for our ocean zones
through Thursday night due to higher seas with SCA wind gusts
developing Thursday night. Non-ocean waters remain mainly below
SCA conditions but wind gusts could occasionally gust to SCA
levels late Thursday night.

Ocean seas will be 8-12 ft Fri morning and peak between 9-14 ft late
Friday evening. Seas will remain high Friday night, then start to
decrease on Saturday as strong offshore flow develops. Seas
eventually drop below 10ft late Saturday, and by Sunday morning,
drop below 5 ft.

Sustained N-NW winds or frequent gusts from Lee could peak at
tropical storm force (35 to 40 kt) Friday night into Saturday,
mainly on the eastern ocean. Elsewhere, SCA conditions likely from
Friday into Saturday, with a few gusts up to 35 kt possible Friday
night/Saturday morning.

.HYDROLOGY...
Most additional rainfall will be less than a half inch but
locally higher amounts are possible in thunderstorms.

Flood watch remains just for New London CT until 2AM Thursday.
Chances for showers and thunderstorms remain. Flood threat
trends down this evening into overnight as chances for
convection lower.

Otherwise, no hydrological issues are expected through early
next week.

.TIDES/COASTAL FLOODING...
A high surf advisory and high rip current risk are in effect
through Saturday evening.

For Suffolk and Nassau ocean beaches, large breaking waves of 5
to 7 ft will steadily build to 10 to 15 ft in the surf zone
Friday. For Brooklyn and Queens ocean beaches, large breaking
waves of 5 to 7 ft tonight will steadily build to near 6 to 12
ft in the surf zone Friday.

Beach flooding and erosion increases Thursday through Saturday.
Widespread dune erosion and scattered overwashes are possible
Friday into Saturday. Dangerous rip currents continue through
the weekend.

Any changes to these coastal hazards will be based on the
current fcst track and intensity of Hurricane Lee. Stay tuned to
the latest from the National Hurricane Center regarding the
forecast for Lee.

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...High Risk for Rip Currents through Saturday evening for NYZ075-080-
081-178-179.
High Surf Advisory until 8 PM EDT Saturday for NYZ075-080-081-
178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Friday for ANZ350-353-355.-- End Changed Discussion --

UPDATE...DW