642
FXUS61 KOKX 031959
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
359 PM EDT Sat May 3 2025

.SYNOPSIS...
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A slow moving cold front will make its way across the region tonight
and stall across the region through Sunday. The system then tracks
through the region into midweek, before lifting north and east. An
associated frontal boundary may linger nearby into late week.
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&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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Severe Thunderstorm Watch in effect for Orange and Putnam
Counties in NY until 8 PM.

As a cold front approaches from the west showers/tstms will become
numerous north/west of NYC. A corridor of moderate instability with
MLCAPE 1500 J/kg will be in place across the Hudson Valley and NW
NJ, with low level SW flow increasing to 25 kt and mid level flow up
to 45 kt, providing ample ingredients for strong to severe
thunderstorms inland NW of NYC this afternoon and evening. Greatest
threat from these storms will be damaging wind gusts.

Thunderstorm chances increase through this evening across NYC
metro area, western Long Island and southern CT but the threat
for severe weather is expected to be more marginal as soundings
do not look as unstable. Convection should wane during the late
evening and overnight, and the frontal boundary should retreat
back to the north as a warm front overnight. Some patchy fog may
be possible where earlier heavier rainfall occurred.

Low temps will fall to the lower 60s in NYC and NE NJ, and into
the 50s elsewhere.
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&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
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On Sunday scattered showers expected mainly during the
afternoon/evening as an Atlantic moisture feed sets up between
the low to the west and offshore high pressure, with the best
chances for heavier rain late Sunday night into Monday. Instability
still appears rather limited, so thinking the threat of thunder
will be low.

Temperatures will not be as warm, with highs in the 60s to
lower 70s, and lows Sunday night in the 50s.
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&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
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An active and unsettled start to the long term with periods of
showers and thunderstorms as an upper level low pressure system
spins over the OH Valley and high pressure to the north and east
steer Atlantic moisture onshore.

Rain is not expected the entire timeframe, but chances for rain
persist thru at least the first half of Wednesday.  Instability and
forcing make for chances of thunderstorms as well within the Monday
night through midweek timeframe. Relatively highest chances of
thunderstorms are forecast Monday thru Tuesday evening. The upper
level low eventually exits east of the region Wednesday into
Wednesday night, with a surface boundary potentially lingering
nearby. Another upper level trough moves into the region behind the
low going into late week.

Overall QPF of a couple of inches, in general, appears likely,
though the long duration of the event should help mitigate more
significant flash flood concerns. See hydro section below for
additional detail.

Temperatures average near to just above normal in the period.
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&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
A stalled frontal boundary will reside in close proximity to
the Lower Hudson Valley through Sunday. This will serve as a
focus for showers and thunderstorms.

Expect mainly VFR conditions outside of any showers and/or
thunderstorms through tonight. There is some uncertainty with
the lowering of ceilings late tonight into Sunday morning. At
this time, have opted to be slower with lowering categories
into Sunday, but ultimately the trend will be for lowering
categories through the day Sunday.

Gusty S/SW winds this afternoon at 10-15kt with gusts 20-25 kts.
KJFK will generally be sustained at 15-20kt. Winds will then
diminish this evening and back to the S/SE overnight at 10 kt or
less. Winds may become more easterly toward daybreak.

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

Winds this afternoon/early evening will vary 170-230 due to the
close proximity of a surface trough. Timing of gusts ending may
vary by 1-2 hours.

Amendments are likely to refine the timing of showers and
thunderstorms.

Chance of MVFR/IFR Sunday morning.

.OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...

Sunday Afternoon: Lowering to MVFR/IFR, especially toward
evening. Showers likely. Slight chance of thunderstorms at the
NYC and Lower Hudson Valleys.

Monday: Showers likely with MVFR or lower expected. A slight
chance of tstms. E winds G15-20kt.

Tuesday: Showers with MVFR or lower expected. A chance of
thunderstorms. SE winds G15-20kt day into early eve possible.

Wednesday: Chance of MVFR or lower with a slight chance of
showers/thunderstorms.

Thursday: VFR

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

&&

.MARINE...
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SCA conditions continue for the ocean from mid afternoon into
tonight, with seas building to 5-6 ft on a long fetch S flow
increasing to 20 kt. A period of SCA conditions also expected
on the south shore bays of Long Island due to an enhanced sea
breeze with gusts up to 25 kt.

Ocean seas likely run near 5 ft Monday thru Tuesday, with SCA
conditions elsewhere unlikely during this time.
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&&

.HYDROLOGY...
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A marginal flash flood risk exists for this afternoon/evening
for inland areas NW of NYC, as tstms there will be capable of
producing 1-1.5 inches of rain in a short period of time. Most
of the impacts should be at nuisance level, but cannot rule out
an isolated flash flood event.

Periods of rain are expected Monday into midweek. There could be
training of showers and thunderstorms at times that result in minor
flooding for excessive runoff in low lying, urban, and poor drainage
areas. The overall risk for flash flooding is low.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ345.
     Small Craft Advisory until 6 AM EDT Sunday for ANZ350-353-355.

&&

$$