okx-afd on 2025-07-24

517
FXUS61 KOKX 241844
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
244 PM EDT Thu Jul 24 2025

.SYNOPSIS...
-- Changed Discussion --High pressure exerts control into Friday afternoon, before a
cold front moves through the area late Friday into Friday
evening. High pressure briefly builds into the area Friday
night into Saturday. A weak frontal system moves across the area
Saturday Night into Sunday. High pressure then builds in for
Monday and Tuesday. A cold front moves across the region mid-
week.-- End Changed Discussion --

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --Upper lever ridge flattens tonight into Friday, as a northern
stream shortwave slides from Ontario/Quebec towards northern New
England. Bermuda high pressure briefly exerts control tonight
into Friday with a strengthening return flow.

Dry but increasingly warm and muggy conditions tonight in gusty
S/SW flow, with lows in the mid to upper 70s for NYC/NJ metro
and lower to mid 70s elsewhere.-- End Changed Discussion --

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
-- Changed Discussion --Key points...

* Heat alerts remain in effect for Friday. One day of 100 to
105F heat indices are expected for most of the area.

* Isolated to scattered severe thunderstorms are possible Friday
aft/eve, with damaging wind gusts the primary threat. There is
also low and localized flash flood threat.

Upper lever ridge flattens Thursday Night into Friday, as a northern
stream shortwave slides from Ontario/Quebec towards northern New
England.

Peak heat and humidity continues on target for Friday with axis
of heat (850mb temps of near 20c) sinking SE towards the region
with likely low-level moisture pooling ahead of approaching
cold front (lower 70s to 75F Td) resulting in heat indices in
the lower 100s to 105F for much of the area. Extreme heat
warning continues for NE NJ with highest confidence in
widespread 105F heat indices, with heat advisories for most of
the remainder of the area with heat indices in the 100 to 105F
range.

In addition to the heat threat, a pre-frontal trough/cold front
will be pressing down on a moderately unstable airmass, with
marginal deep layer shear presenting potential for isolated to
scattered severe thunderstorms in the late aft/eve. Models in a
bit better agreement on a more distinct convectively enhanced
vort axis (originating from a Mid- Mississippi river shortwave
this afternoon) approaching the area tomorrow afternoon and
crossing in the evening. Along with potential of a bit better
alignment of steering flow/shear with the front in a w to e
fashion as the front sags south, this would favor a lean towards
a scattered to broken line of of thunderstorm activity, and
scattered severe threat for much of the area.

Limiting factor for organized convection continues to be weak
shortwave forcing/height falls this far south as compared to
central and northern New England, marginal deep layer shear, and
weak mid- level lapse rates. Primary threat will be damaging
wind gusts from wet downbursts in primarily a uni-directional
WNW flow aloft, high PWAT environment with a bit of mid-level
dry air entrainment potential, and steep low-level lapse rates.
See hydrology section for low and localized flash flood threat
in a 2+ STD PWAT environment ( 2 1/2"-2 1/2" PWATs)

Cold front expected to push SE of the region by midnight Friday
as northern stream shortwave slides through northern New
England, with a relatively cooler and drier airmass filtering
in its wake as high pressure builds into the region.

Northern stream shortwave slides east of northern New England
Saturday AM, with northern periphery of southern ridging nosing back
into the area. At the surface, high pressure briefly build towards
the region from the north on Saturday and overhead Saturday Night.

Dry conditions expected on Saturday, with noticeably drier and cooler
airmass advecting in on gusty N/NE flow on Saturday, although
still running slight above seasonable with highs in the mid to
upper 80s, and heat indices similar. Near seasonable temps for
Saturday Night with increasing humidity levels as return flow
develops.-- End Changed Discussion --

.LONG TERM /SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --Key Points:

* Showers and thunderstorms expected the second half of Sunday with
a frontal system. Some thunderstorms will be capable of gusty
winds and heavy rainfall.

* High heat and humidity return early to mid next week. Latest
forecast has widespread upper 90s Max Heat Index values for
Monday, with upper 90s to low 100s on Tuesday. There is potential
for hot and humid conditions to linger into Wednesday, but this
will depend on timing of a cold front.

* The cold front moves across the area mid-week. This will end the 2-
3 days of hot and humid conditions. Showers and thunderstorms
likely accompany the frontal passage.

Stuck close to the NBM, with the biggest changes being to lower
dewpoints next week. The NBM has been consistently a bit too high
with dewpoints on days where deeper mixing is expected.

Other uncertainty with the forecast lies on exact evolution and
timing of a weak frontal system that may impact the area Sunday. Low
confidence PoPs given the offshore high trending stronger and
potential for an MCS to bleed into the area.

Otherwise, there is also some disagreement on timing of a cold
frontal passage mid week. Latest GFS holds off the front until later
on Wednesday. This could allow higher heat and humidity to linger
into Wednesday, especially for the southern half of the area like
northeast NJ, NYC and Long Island.-- End Changed Discussion --

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
High pressure remains over the area terminals.

VFR.

S-SW winds less than 10 kt will increase to 10-15kt with gusts
20-25kt from late morning through early evening. Winds diminish
after 00z.

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

Can not rule out a few occasional guts over 25kt. Timing of
gusts may be +/- 1 hour from TAF.

.OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY...

Friday: VFR likely through morning, possibly followed by periods of
sub VFR in showers and thunderstorms for the afternoon and
evening. Southwest winds G15-20kt.

Saturday: VFR with widely scattered showers and thunderstorms
during the afternoon and at night possible.

Sunday: Mainly VFR. MVFR or lower possible in any showers or
thunderstorms.

Monday: Mainly VFR.

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

.MARINE...
-- Changed Discussion --Marginal 25 kt gusts are possible in a S flow late this
afternoon into tonight on the ocean waters, mouth of NY Harbor
and southern bays of W LI, and possibly Fri aft/eve ahead of a
cold frontal passage. Isolated to scattered severe
thunderstorms are possible ahead of a cold front passage Friday
afternoon through the evening.

A brief period of 20 kt gusts are possible in wake of cold
frontal passage Saturday night into Sunday morning.

Given a weak pressure gradient, winds and waves will largely stay
below Small Craft Advisory criteria Sunday through the middle of
next week. The best chance at getting close to 25 kt gusts right now
will be ahead of and behind a cold frontal passage sometime late
Tuesday or Wednesday.-- End Changed Discussion --

.HYDROLOGY...
-- Changed Discussion --Primarily a minor urban and poor drainage flooding threat with
scattered thunderstorm activity Friday afternoon that could
produce rainfall rates of 2+"/hr with PWATS as high as 2"-2
1/2", but will be overall progressive limiting duration over an
one area. Based on these potential rainfall rates, there is a
low and localized flash flood threat with any localized
repetitive thunderstorm activity, particularly if the cold front
orients in a more W to E fashion as indicated by some CAMs. A
general 1/4 to 3/4" basin average, with a low and localized
probability for 2-3" in only a couple of hours with any
training.

Showers and thunderstorms associated with a frontal system
could produce locally heavy downpours on Sunday that result in
nuisance flooding, but the overall flood threat appears low at
this time.-- End Changed Discussion --

.TIDES/COASTAL FLOODING...

-- Changed Discussion --There is potential for a late day high rip current risk across
Nassau and Queens beaches this afternoon into evening with
coastal jet development.

A moderate rip current risk is likely on Friday with southerly
wind waves building to 3 to 4 ft.-- End Changed Discussion --

.CLIMATE...
Daily record high temperatures maybe be tied or broken Friday
July 25th. Here are the current records for the day...

EWR 99/2016
BDR 93/2001
NYC 97/1999
LGA 97/1999
JFK 93/2010
ISP 94/1987

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...Air Quality Alert until 11 PM EDT this evening for CTZ005>007.
Heat Advisory from 11 AM to 8 PM EDT Friday for CTZ005>011.
Air Quality Alert from 11 AM to 11 PM EDT Friday for
CTZ009>012.
NY...Heat Advisory from 11 AM to 8 PM EDT Friday for NYZ067>075-
078>080-176>179.
NJ...Heat Advisory from 11 AM to 8 PM EDT Friday for NJZ002.
Extreme Heat Warning from 11 AM to 8 PM EDT Friday for NJZ004-
006-103>108.
MARINE...None.-- End Changed Discussion --

SYNOPSIS...JT/NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...JT
AVIATION...20
MARINE...JT/NV
HYDROLOGY...JT/NV
TIDES/COASTAL FLOODING...NV
CLIMATE...NV