582
FXUS61 KOKX 131445
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1045 AM EDT Wed Aug 13 2025
.SYNOPSIS...
-- Changed Discussion --
A cold front approaches today, slowly moves across the region
Thursday, then moves offshore Thursday night. High pressure then
builds over the region through Saturday before another cold
front approaches from the Great Lakes on Sunday, moving through
Sunday night. The front may then stall nearby as high pressure
attempts to return from the north early next week.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH TONIGHT/...
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A cold front approaches the region today. This cold front
approaches western parts of the region by late today into
tonight. There is not much forcing with the front. Bulk shear
0-6 km AGL max near 20 kt and surface CAPE max near 1000 to 2000
J/kg, so not expecting much severity with thunderstorms.
However, models do indicate some small areas with bulk shear 0-6
km AGL closer to 25 kt and if higher CAPE such as NAM pans out,
thunderstorms could grow taller and stronger. A marginal threat
severe thunderstorm therefore exists across the region today
into this evening, with potential for severe downbursts. These
thunderstorms could also easily produce heavy rain considering
near 2 inches PWATs predicted over the region.
The SW flow continues today which could become gusty along the coast
this afternoon. The southerly winds decrease tonight and begin to
shift more westerly into early Thursday.
In terms of thunderstorms, they look most probable this
afternoon into this evening, then shift to be more offshore late
tonight. Pre-frontal trough and interactions with any sea
breeze could make for initiation of convection. For late
tonight, patchy fog could develop with the moisture laden
boundary layer. Showers chances this afternoon will remain
through the night for much of the area.
Concerning the temperatures and heat indices, the forecast used the
NBM for the max temperatures but a blend of MET MOS, MAV MOS and NBM
for the dewpoints as dewpoints from NBM along seemed too high. Max
temperatures are overall pretty similar to the previous day although
the immediate coastlines are slightly cooler. Max temperatures range
from near 80 to near 90. Max heat indices are in the mid to upper
90s for parts of NYC, parts of Northeast NJ, parts of the Lower
Hudson Valley as well as parts of Southern CT. Otherwise,
mostly lower 90s for max heat indices. Taking the previous day
heat indices into account (just lower 90s max heat indices
mostly), conditions are expected to remain below heat advisory
thresholds across the area today. We are not getting the 2 days
in a row of 95 to 99 degree heat index.-- End Changed Discussion --
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
Cold front eventually moves through the region Thursday and
offshore into the evening hours. There will still be chances
for showers and thunderstorms remain across the region.
With a lack of bulk shear (max appears to be near 20 kt 0-6 km
AGL) as well as CAPE limited to near 1000 to 1500 J/kg not
expecting any severe thunderstorms. However, lessening steering
flow aloft will allow for slower moving thunderstorms and for
multiple rounds of showers and thunderstorms. Hydrology will be
more of an issue with these showers and thunderstorms on
Thursday. Slow moving front and enhanced low convergence along
the front will make for larger aggregate areas of showers and
thunderstorms.
Because of this, went a little lower with max temperatures. For
parts of the region, northerly flow develops which will help
limit dewpoints.
Overall expecting a cooler but still somewhat humid day. Max
temperatures range within the 80s, highest around NYC Metro and
parts of the interior, upper 80s. Max heat indices with dewpoints
mainly upper 60s to near 70, mainly lower 90s.
High pressure from Southeast Canada builds into the region Thursday
night through Friday night. Mainly dry conditions are expected
Thursday night. Dry conditions are expected Friday through Friday
night.
Flow becomes more northerly Thursday night and then more
easterly Friday and Friday night. Lower dewpoints are expected,
down more in the 60s. Temperatures Friday will be similar to
those of Thursday but the lower dewpoints make for heat indices
nearly the same as the actual temperature. Low temperatures
trend cooler Friday night (near 60 to near 70) compared to
Thursday night (low 60s to low 70s).
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
No significant changes made and the NBM was followed for this
period.
Relatively quiet and pleasant start to the weekend with ridging in
place and surface high pressure building over the region. Dry
conditions prevail Saturday as a result, with temperatures close to
normal for mid August, generally low to mid 80s. The high shifts
offshore and flow in the low levels becomes SW Saturday night. A
cold front begins to advance south and east toward the region Sunday
as broad troughing slides east over Canada. This introduces the next
chance for showers and thunderstorms by Sunday afternoon as a
prefrontal trough moves in. The SW flow helps advect in some warmer
air ahead of the boundary, and Sunday looks to be the hottest day of
the period, with upper 80s and low 90s for most away from the coast.
Doesn`t appear at this point though that sufficient moisture in the
BL will be present to allow for super sultry conditions, so heat
indices near or just above those air temperatures wouldn`t warrant
a heat advisory as it stands now.
While high pressure attempts to build in behind the frontal passage,
the boundary appears likely to linger nearby early next week as a
broader trough remains in place over eastern Canada and extends into
the Northeast, keeping ridging to the west. A developing frontal
wave off to the west could keep chances for precip at times Monday
and Tuesday, but confidence at this point is low.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
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A cold front approaches from the Great Lakes today into
tonight, moving through on Thursday.
Mostly VFR. Approaching cold front introduces chances for
scattered showers and thunderstorms this afternoon and evening.
Thunderstorm threat generally between 19Z on the early side
through around 03Z Thu, with some lingering showers possible
overnight. Best chance for TSRA at NYC terminals between 20Z and
1Z.
SW to S flow around 10 kt. Flow lightens tonight once again and
goes vrb at most terminals, which may persist through much of
Thursday morning.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Timing of aft/eve convection may be off by an hour or two.
.OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...
Thursday: Mainly VFR. Chance of showers and thunderstorms.
Thursday night-Sunday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
The pressure gradient will be rather weak through tonight and
into the start of the weekend. Conditions on the waters are
expected to remain below small craft advisory (SCA) thresholds.
With a weak pressure gradient in place, winds and seas are expected
to remain below SCA criteria this weekend and early next week.
&&
.HYDROLOGY...
Minor nuisance flooding within urban, low-lying, and poor
drainage areas is possible with heavy showers and thunderstorms
this afternoon through Thursday. Tonight into Thursday,
thunderstorms slow down and front enters the region, making for
an elevated flooding threat.
Excessive rainfall outlook depicts marginal flood threat for
interior areas today into tonight and then more of the local
region for Thursday. HREF does depict some possibility for
rainfall rates to reach near 1 inch per hour for parts of the
region.
PWATS near 2 inches and slower thunderstorm movement as well as
training of cells will enable for multiple periods of heavy
showers and thunderstorms. There is a very low probability for
flash flooding. Though, any flash flooding should be quite
localized.
Overall basin averaged rainfall amounts forecast range from
near a quarter to near 1 inch of rainfall this afternoon through
early Thursday evening.
Otherwise, there are no significant hydrological concerns
thereafter through early next week.
&&
.TIDES/COASTAL FLOODING...
Moderate risk of rip currents is forecast across all the ocean
beaches today and a low risk of rip current is forecast for all
ocean beaches on Thursday.
An onshore swell closer to 2 ft today is expected to lower by
around 1 foot for Thursday. Winds will also be much lighter on
Thursday and variable in direction compared to today when a more
steady southerly onshore flow of near 10-12 kt is forecast.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Air Quality Alert until 11 PM EDT this evening for CTZ005>007.
NY...None.
NJ...None.
MARINE...None.-- End Changed Discussion --
&&
$$
SYNOPSIS...JM/DR
NEAR TERM...JM/DW
SHORT TERM...JM
LONG TERM...DR
AVIATION...JC/DR
MARINE...JM/DR
HYDROLOGY...JM/DR
TIDES/COASTAL FLOODING...