Area Forecast Discussion
Issued by NWS Upton, NY

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426
FXUS61 KOKX 161950
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
350 PM EDT Wed Jul 16 2025

.SYNOPSIS...
Stalled frontal boundary dissipates across the region with
otherwise low pressure well to the northwest through early
Thursday. An associated cold front approaches Thursday and moves
across Thursday night. Weak high pressure builds in thereafter
for Friday. This high pressure area builds overhead Friday night
and moves offshore Saturday. A frontal system will impact the
region Saturday night and Sunday. High pressure builds to the
north Monday.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Mainly dry conditions expected to continue into this evening.
Temperatures have warmed up well into the 80s with some lower
90s being observed. The airmass is quite humid with dewpoints
well into the 70s. As a result, heat indices today have been
widespread mid to upper 90s across the entire area, including SE
Suffolk County. Heat advisory has been expanded to include SE
Suffolk County. Now, the whole forecast region is in the heat
advisory.

Now, with some weak low level convergence with stalled weakening
dissipating frontal boundary and daytime instability, could be
an isolated to widely scattered shower or thunderstorm into
early this evening.

Otherwise, the next main chance of showers and thunderstorms is
forecast for late tonight from west to east with a mid level
shortwave moving in and increase in elevated instability. Heavy
rain and gusty winds will be possible with the thunderstorms.

Blended in consensus MOS with NBM for lows to increase them
slightly. These stay well into the 70s for much of the area. In
addition, some patchy fog is expected to develop outside of NYC
and may become locally dense.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
First, hazard of heat advisory ongoing. This will end 10PM
Thursday evening. With the drier trend of model convection for
Thursday afternoon, especially for locations farther east, feel
that uncertainty grows with temperatures possibly being higher
than forecast. Forecast sent out went above NBM by a degree for
the entire area Thursday and 2 degrees above NBM Thursday for SE
Suffolk, which may end up hardly receiving any rainfall for
this next frontal event. Max heat indices for Eastern Suffolk in
the 95-100 degree range with otherwise most other locations
near 100 degree heat index Thursday.

For Thursday, active convection expected in the morning with
that mid level shortwave. Again, could have some gusty winds
and torrential downpours with the thunderstorms. Some lingering
morning fog can be expected, especially for eastern coastal
locations. Locally dense fog will be possible.

Some degree of organization is expected with the morning
thunderstorms as low level jet is noted by forecast models to
increase to near 20-30 kt. Helicity will be limited with low
level winds stay from the south to southwest. So, main threat
would be strong downbursts of wind.

Then, after morning convection passes east of the region, there
could be quite a lull in convective activity for the rest of the
day. Models have trended less in convective coverage compared to
previous forecast. Did not want to make significant changes just
based on 12Z model run suite and still wanted to convey and
keep the chance of showers and thunderstorms. With that being
stated, did lower the POPs closer to 30 percent taking NBM and
the previous forecast with equal weights. Lesser POPs for
eastern coastal areas Thursday afternoon.

Contributing to this decrease in model convection is weaker
positive vorticity advection with some models even indicating
negative vorticity advection in the afternoon. PWATs are also
forecast to lower as well, going from nearly 2 to 2.2 inches
early day to near 1.7 to 1.8 inches by late day.

Winds are also forecast to increase as well with parent low
deepening slightly as it travels just north of the US Canadian
border Thursday into Thursday evening. 925mb flow stays near
20-25 kt through the day. This helps mitigate the flood threat
but will keep a marginal severe threat for thunderstorms for
strong downbursts of wind with these faster moving thunderstorms.

Cold front moves across Thursday night with high pressure to
follow for late Thursday night through Friday. Showers and
thunderstorms possible early Thursday evening and then trending
drier. Dry conditions forecast thereafter through Friday. The
high pressure area late Thursday night into Friday will have its
airmass in the Great Lakes. This will make a noticeable
difference in terms of lower temperatures and dewpoints compared
to previously.

Thursday night, cooler temperatures expected with a range from
the upper 60s to lower 70s for much of the area, and NYC staying
more in the mid 70s. For Friday, warm temperatures for highs
well into the 80s forecast but dewpoints will be more in the
60s. As a result, max heat indices are mostly in the upper 80s
to lower 90s Friday, below heat advisory criteria.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
With the passage of a cold front early Friday, more seasonal
temperatures, along with drier air, will be ushered into the region
for Friday night into the beginning of next week.
However, with surface high pressure moving offshore during Saturday,
and the approach of a warm front, humidity levels will be slowly
increasing, with dew points rising back into the mid 60s Saturday
and into the lower 70s Sunday. With a frontal system passes near the
region there will be a chance of showers and thunderstorms Saturday
night and Sunday. A cold frontal passage Sunday night will bring
somewhat drier air, with an east to southeast flow as high pressure
builds to the north, and moves off the New England coast.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
A trough of low pressure will remain nearby through Thursday.

Mainly VFR today. Showers and thunderstorms will be possible from
the city terminals and points west at any time this afternoon and
tonight, but most likely during the PROB30 period.

S to SE winds mostly around 10kt this afternoon, becoming more S to
SW tonight at 5-10kt, then increasing to around 15kt from the SW
with gusts 20-25kt Thursday afternoon.

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

Occasional gusts 15-20kt possible this afternoon. Amendments
possible this afternoon/evening for shra/tsra or potentially
just VCTS.

TSRA could be just isolated at most during the PROB30 period.

.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...

Thursday PM: Afternoon/evening showers/tstms possible with MVFR or
lower cond.

Friday and Saturday: Mainly VFR.

Sunday: Chance of showers and tstms. MVFR or lower likely.

Monday: VFR.

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

&&

.MARINE...
Through tonight, conditions are below SCA criteria with a weak
pressure gradient in place. For Thursday and Thursday night, the
pressure gradient increases and potentially there could be some
SCA level wind gusts to 25 kt across parts of the ocean. For
Thursday night, there could be enough fetch for some 5 ft seas
as well on the ocean. It will be marginal for SCA conditions on
the ocean and did not have enough confidence at this time to
issue SCA for the ocean. Well below SCA for other waters. SCA
potential relatively higher for ocean east of Fire Island Inlet.
Also, the period of time SCA conditions could occur would be
brief as forecast conditions for winds and seas lower on Friday
with high pressure building in.

Conditions remain below SCA thresholds Friday night through Monday
night.

&&

.HYDROLOGY...
Localized flash flooding possible through early Thursday morning
with high PWATs and less steering motion with thunderstorms.
Less flooding threat Thursday into early Thursday evening as
thunderstorms pick up in speed but minor flooding will still be
possible.

Hydrologic impacts are not expected thereafter through the
middle of next week.

&&

.TIDES/COASTAL FLOODING...
The rip current risk remains low into this evening with a light
southerly flow and around 2 foot waves. With a strengthening
southwest flow Thursday, the risk for rip current development will
be moderate, and wave will be 2 to around 3 feet. A moderate rip
current risk will continue into with the passage of a cold front
early in the day, and winds from the northwest to west, and a
southerly swell remains.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT this evening for CTZ005-009.
     Heat Advisory until 10 PM EDT Thursday for CTZ005>012.
     Air Quality Alert from 11 AM to 11 PM EDT Thursday for CTZ009-
     010.
NY...Air Quality Alert until 11 PM EDT this evening for NYZ069>075-
     078>081-176>179.
     Heat Advisory until 10 PM EDT Thursday for NYZ067>075-078>081-
     176>179.
NJ...Air Quality Alert until 11 PM EDT this evening for NJZ002-004-
     006-103>108.
     Heat Advisory until 10 PM EDT Thursday for NJZ002-004-006-
     103>108.
MARINE...None.

&&

$$

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