346
FXUS61 KOKX 132130
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
530 PM EDT Wed Aug 13 2025

.SYNOPSIS...
A pre-frontal trough ahead of a cold front across the eastern
Great Lakes will move into the area this evening where it will
become nearly stationary. The cold front will then very slowly
work west to east across the area Thursday afternoon and night.
High pressure then builds over the region through Friday night
before moving offshore Saturday. A cold front approaches Sunday,
moving through late in the day into Sunday night. The front may
stall nearby, as waves of low pressure move along the boundary
into early next week. Meanwhile, high pressure attempts to return
from the north early next week.

&&

.NEAR TERM /THROUGH THURSDAY/...
The combination of a mid-level shortwave trough and an
approaching surface trough will produce a round of showers and
thunderstorms into this evening. The brunt of the activity will
work across the Lower Hudson Valley, interior NE NJ, interior
SW CT, and NYC early this evening before weakening and working
across eastern CT and LI. The severe weather threat is low with
weak mid-level lapse rates and lack of deep-layer shear. However,
moderate instability and high PW (increasing to 2") could produce
a few strong thunderstorms with locally heavy rainfall. The SPC
HREF shows high neighborhood probabilities (greater than 50
percent) for an inch/3hr, mainly from NYC and points north and
west. For 3"/3hr, the same probabilities get to only around 10
percent. WPC also has the area in marginal risk of excessive
rainfall, which mean the potential is there for isolated flash
flooding. For the second half of the night, chances for showers
and thunderstorms will decrease. However, NBM PoPS were used and
may be too high based on latest CAMs. The CAMs show very little
activity after 10 PM this evening with the airmass stabilizing
some and deep lift translating east.

Patchy fog is also a possibility overnight with light winds and
high dew point air in place. The fog could persist in spots
after daybreak for 2 to 3 hours.

The surface trough lingers across the area Thursday before the
cold front merges with it. This will potentially result in
another round of showers and thunderstorms, mainly in the
afternoon. Once again, latest CAMs are relatively inactive
during the morning hours. Environment remains weakly sheared and
moderately unstable. Thus, the severe weather threat remains
low. However, high PW air remains in place and steering winds
will be light. This will keep the area under a isolated threat
of flash flooding. WPC has much of the area under a marginal
risk of excessive rainfall.

Rainfall amounts through Thursday are generally less than half
an inch on average, but localized higher amounts of an inch plus
are possible.

It will remain warm and muggy tonight with lows mainly in the
lower and mid 70s. This is about 3 to 5 degrees above normal.
Highs on Thursday are expected to come down some due to the
presence of more cloud clover. However, temperatures could be
slightly warmer if more sunshine is achieved. Highs will be
mainly in the mid to upper 80s, but cooler along the south shore
and east of LI. This is about 5 degrees above normal. NBM and
MOS temperatures are very close during this time.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
Cold front will slowly drop south Thursday night into Friday
with any lingering convection ending early in the evening. High
pressure then builds in from the north through Friday. While the
airmass is not whole lot cooler, an easterly flow should cool
the boundary layer some. It will also become slightly less
humid. Forecast area will reside close to the northern edge of
a cloud shield and some of the 12Z guidance has trended toward
more clouds across the area. NBM at this time keeps clouds to
the south.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
The beginning of the long term period will be quiet with
temperatures near seasonal normals with high pressure over the
region. High pressure will be offshore Sunday as a cold front
approaches, and moves through late day into Sunday night. With a
return flow temperatures Sunday will be in the lower 90s inland and
upper 80s along the coast. And the combination of dew points in the
upper 60s to lower 70s will produce heat indices in the mid 90s.
Sunday will be the only day of heat and humidity as temperatures
return to near or below seasonal levels behind the cold front Monday
into Wednesday. And drier air will be moving in as high pressure
builds to the north. The cold front is expected to stall somewhere
south of the region late Sunday night, and weak waves of low
pressure move along the boundary Monday through Wednesday. With this
possibility there are at least slight chances of precipitation,
although there will be dry periods at times as well. The NBM was
followed throughout the extended period.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
A cold front slowly approaches today into tonight, moving through
Thursday.

Mostly VFR. Overall better chances of showers and thunderstorms for
KSWF this afternoon, but will still continue with PROB30 this
afternoon into early evening for most other terminals. Additional
showers possible thereafter until around midnight.
Shower/thunderstorms increase once again Thursday afternoon.

S flow 10-15kt with gusts 16-20kt. Flow lightens tonight, going
variable in direction at most terminals, which may persist through
much of Thursday morning or become northerly. Increasing southerly
flow then follows in the afternoon.

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

Timing of aft/eve convection may be off by an hour or two. Gusts
this afternoon might be only occasional. Winds at KJFK could be
forecast to be 3-5kt too low this afternoon, and some gusts to 20-
24kt would be possible.

.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...

Thursday: Mainly VFR. Chance of showers and thunderstorms.

Thursday night-Sunday: VFR.

Monday: Morning -shra and MVFR possible, otherwise mainly VFR.

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

&&

.MARINE...
The pressure gradient will be rather weak through early next
week. Conditions on the waters are expected to remain below
small craft advisory (SCA) thresholds.

&&

.HYDROLOGY...
WPC has the area under a marginal risk of excessive rainfall
through Thursday. Weak steering winds and PW values around 2
inches will produce localized heavy rainfall with the potential
for instances of isolated flash flooding. Overall, basin
averaged rainfall amounts are less than an inch.

Otherwise, there are no significant hydrological concerns
thereafter through early next week.

&&

.TIDES/COASTAL FLOODING...
For Thursday, a moderate risk for the development of rip
currents is forecast at the New York City ocean beaches, with a
low risk at the Nassau and Suffolk counties beaches.

For Friday there is a low risk for the development of rip
currents at all the ocean beaches.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT this evening for CTZ005>007.
NY...None.
NJ...None.
MARINE...None.

&&

$$

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