okx-afd on 2025-05-19

883
FXUS61 KOKX 200155
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
955 PM EDT Mon May 19 2025

.SYNOPSIS...
-- Changed Discussion --Weakening high pressure over the Great Lakes and Ohio Valley
states will build slowly east tonight and into the area on
Tuesday. The high then slowly starts to give way to a broad area
of low pressure approaching from the southwest Tuesday night into
Thursday. The low then moves northeast and into the Canadian
Maritimes Thursday night through Saturday. Weak high pressure then
builds in Saturday night through Monday.-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --N/NW winds will gradually subside overnight with most locations
losing gusts by the early morning hours. Coastal locations may
see occasional gusts to around 20 mph linger until around
daybreak. Cloud cover has been a bit more extensive than
forecast across much of eastern CT and the twin forks of LI.
Much of the guidance doesn`t seem to be handling it well and
used a blend of the 18Z NAM and GFS overnight versus the model
consensus solutions (NBM, CONSALL/SHORT). This cloud cover may
linger into Tuesday as it gets trapped beneath a subsidence
inversion.

Temperatures are expected to range from the lower 40s to the lower
50s.-- End Changed Discussion --

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Winds continue to diminish Tuesday with weak high pressure over the
area. Expect any northerly winds to become light and variable
by late morning or early afternoon. It should be a mostly sunny
day, however a weak shortwave that passes northeast of the area
may bring some increased cloudiness to the eastern portions of
the CWA.

The weak high over the area slides east late Tuesday into Tuesday
night. This will allow a weather system over the middle portion of
the country to approach the area. Expect an increase in cloud cover
Tuesday night. It should remain dry Tuesday night, however some
light rain will be possible towards daybreak across the western edge
of the area.

High temperatures on Tuesday will be in the middle and upper 60s, to
lower 70s. Tuesday night lows fall into the upper 40s and lower to
middle 50s.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Global models in general agreement regarding the h5 pattern through
the long term. A ridge over us on Wednesday flattens as a closed low
slowly moves from the northern Great Lakes Region eastward through
the Northeast through this weekend, then into the Canadian Maritimes
on Monday. This will bring us an extended period of rain threat with
the greatest chances occurring Wednesday afternoon through Thursday
evening.

At the surface, a double-barreled low moves closer to us from the
south and west on Wednesday. The circulation center emerging off the
Mid-Atlantic Coast during Wednesday night strengthens and eventually
passes not too far offshore during Thursday. Rain slowly overspreads
the forecast area from SW to NE across the area through the day
Wednesday. Rainfall then looks to be more on the moderate side in
terms of intensity Weds night into Thurs morning as a low level jet
enhances lift, coinciding with time that the deepest moisture is
shifting through as indicated by forecast PWATs. See the hydrology
section below for potential impacts with this system. Rain chances
then drop off during Thursday night as the low continues on its NE
path towards Nova Scotia. A cyclonic flow aloft with occasional
shortwaves passing through keeps the threat of a shower on Friday,
which afterwards may be more diurnally-driven for both days this
weekend as well as on Monday.

NBM looked reasonable for temperatures through the long term. Cooler
than normal Weds-Friday, then warming to near normal this weekend.

&&

.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --Low pressure over the Canadian Maritimes will track slowly
southeast out into the western Atlantic, while weak high
pressure builds in from the west.

Mainly VFR thru the TAF period. Brief MVFR possible at KGON
Tuesday morning. MVFR ceilings may begin to work into the
eastern terminals after 00Z Wednesday and around 06Z or later
at the NYC and Lower Hudson Valley terminals.

NW-N wind gusts 25-30kt will gradually diminish with many of
the terminals losing gusts by 06Z. However, coastal locations
may see gusts up to 20kt linger through daybreak. N winds around
10kt to start on Tuesday will weaken through the day and veer
around to the NE in the afternoon. However, the flow could
weaken enough for seabreeze development. Thus, there is lower
confidence in wind direction at the coastal terminals Tuesday
afternoon.

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

Chance of an afternoon seabreeze Tuesday, but low confidence at
this time.

.OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...

Tuesday Night: MVFR likely developing from west to east
overnight.


Wednesday: MVFR or lower with rain developing from west to east
through the day. E wind gusts up to 20kt.

Thursday: MVFR or lower with rain, especially in the mrng. E winds
backing to the NE thru the day with gusts up to 30kt. Wind
diminishing at night/

Friday: MVFR or lower with a chance of showers.

Saturday: Chance of MVFR in showers. NW G15-20kt.

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

&&

.MARINE...
-- Changed Discussion --With cold advection in the NW flow, have extended SCA on all
waters through 4 AM. Airmass may stay better mixed for a bit
longer. Winds are expected to diminish below 25kt by this time
with sub-SCA conditions through at least Tuesday night.

SCA conditions on most, if not all waters Wednesday through Thursday
as low pressure passes offshore with an east to northeast flow
increasing to 15-25kt with around 30kt gusts. Could be some gale
force gusts on the ocean as well during late Weds night into Thurs
morning, but not enough confidence at this time for a Gale Watch for
a late 4th into 5th period event. Seas probably remain elevated with
a residual swell for a period thereafter, so advisory conditions
probably continue into Friday on the ocean. Sub-advisory conditions
then follow for Saturday.-- End Changed Discussion --

&&

.HYDROLOGY...
Rainfall from Wednesday through Thursday night is anticipated to be
in the range of mostly an inch to 1.5 inches with locally higher
amounts possible. The rainfall will probably be at its heaviest
during Wednesday night into Thursday morning. Impacts will most
likely be limited to minor urban/poor drainage flooding and
perhaps small stream flooding as well. The flash flood threat
remains low when considering current flash-flood guidance values
plus a lack of convection to enhance rainfall in only a modest
PWAT airmass. NBM could be underestimating rainfall amounts as
it did with last week`s system, so can`t completely rule out
isolated flash flooding. WPC continues with a marginal risk of
flash flooding during this period.

&&

.TIDES/COASTAL FLOODING...
A strengthening/persistent E-NE flow Wednesday through Thursday
should bring minor coastal flooding late this week. The two
high tide cycles of concern are late Wed night/early Thu morning
and late Thu afternoon/early Fri evening. The first of these is
lower astronomically and should bring only localized flooding
to some spots in/around the tidal waterways of NE NJ and Staten
Island, and along the south shore bays of Nassau County. The
second round should be widespread, with departures 2.0 to 2.5
ft, as winds appear more likely to remain NE through the day Thu
and not back N until Thu night.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 4 AM EDT Tuesday for ANZ331-332-335-
     338-340-345-350-353-355.-- End Changed Discussion --

&&

$$

SYNOPSIS...BC/JC/DW
NEAR TERM...BC
SHORT TERM...BC
LONG TERM...JC
AVIATION...DW
MARINE...BC/JC/DW
HYDROLOGY...JC
TIDES/COASTAL FLOODING...