233
FXUS61 KOKX 211741
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
141 PM EDT Mon Jul 21 2025
.SYNOPSIS...
High pressure builds this afternoon and remains in control
through Thursday. A low passing into east Quebec Friday will
bring through a cold front late Friday into Friday night.
&&
.NEAR TERM /THROUGH TONIGHT/...
The cold front is well south of the area and Canadian high
pressure is building in, bringing a cooler and drier airmass to
the area. In the upper levels, weak troughing will remain as an
upper level low swings through eastern Canada and northern New
England.
Mostly sunny and dry conditions are expected this afternoon.
The NBM was followed closely except for dewpoints and tonight`s
lows due to normal biases.
The air will have a more comfortable feel this afternoon with
highs in the upper 70s to middle 80s and dewpoints in the lower
60s, and into the 50s getting later into the afternoon and
evening. Thus, a noticeably cooler night is expected. With
clear skies, the dry airmass and mainly a light wind,
temperatures should bottom out in the lower 50s across the
interior. Winds may stay up a bit at the coast where lows in the
60s are more likely.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Quiet conditions continue in the short term. High pressure moves
overhead Tuesday and offshore Tuesday night into Wednesday.
Aloft, we remain under weak troughing or zonal flow until a
ridge starts building in on Wednesday.
The cooler and drier conditions continue until the high moves
offshore and moisture begins to increase with a return flow.
Highs Tuesday will be even lower than today, in the mid 70s to
low 80s. Radiational cooling conditions wont be as good Tuesday
night with more of an onshore flow so lows will be a bit warmer.
By Wednesday highs are back in the upper 80s to low 90s.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Key Messages:
* Dry Wed through Thu night.
* Showers & thunderstorms possible with cold front Fri/Fri night
then again from the front stalling to the south late on Sat.
* Temps climb into Thu. Heat index may exceed 100 by Fri.
AN upper level ridge flattens Thursday into Thursday night. A
series of midlevel shortwaves then pass Friday into the weekend.
High pressure shifts offshore into Thursday. A low passing into
east Quebec Friday moves into the North Atlantic Friday night
into Saturday. This low brings through a cold front late Friday
into Friday night. The cold front then stalls south of the area
into Saturday.
Thursday through Friday, temperatures will warm each day in
response to the high moving east and higher heights aloft. Heat
index values may exceed 95 on Thursday for parts of the area and
even near 100 in select locations, then exceed 100 for large
portions of the area on Friday with some spots exceeding 105.
This means we should see solid heat advisory criteria on Friday
with heat warning criteria possibly being met in some areas. The
heat, while lower, will still be strong into Saturday.
Given ample heating, shortwave energy passing aloft, high dewpoints
& atmospheric moisture, and lift from an approaching/passing cold
front, scattered showers and thunderstorms are expected late Friday
into early Friday night. Showers and thunderstorms will again be
possible Saturday afternoon into early early Saturday night due to
the front stalled nearby to the south with another shortwave passing
aloft.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
High pressure builds in from the northwest through tonight, and
remains over the region Tuesday.
VFR through the forecast period.
Winds N/NW, around 10 kt or less. Occasional gusts are possible,
through this afternoon. Winds may back to W for a few hours mid
to late afternoon at the Connecticut and Long Island coastal
terminals. Winds become NE overnight then E on Tuesday around 10
kt or less.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Occasional gusts up to 20 kt possible through mid afternoon.
.OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...
Tuesday through Thursday: VFR. Thursday, south winds G20-25kt,
highest at the coast.
Friday: VFR likely through morning, possibly followed by periods of
sub VFR in showers and thunderstorms for the afternoon and evening.
Saturday:VFR with afternoon thunderstorms.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Occasional nearshore gusts to 25 kt possible through this evening in
a gusty NW flow behind the cold frontal passage.
Otherwise, winds and waves are expected to stay below Small Craft
Advisory criteria through Wednesday night as high pressure
moves overhead.
Winds may approach SCA gusts on waters both late Thursday and then
again late Friday with the approach of a cold front.
&&
.HYDROLOGY...
-- Changed Discussion --
There are no hydrologic concerns through this week and into the
weekend.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
A low rip current development risk is expected for all ocean beaches
today with a mixture of mainly 1 ft S/SE swells. Similarly a low rip
current development risk is likely for Tuesday with developing 2 ft
easterly wind wave and a series of 1 ft S/SE swells. With that said,
with a large tidal range due to an approaching new moon, rip
development could be moderate a couple of hours either side of low
tide. Additionally, if an easterly flow is stronger than
forecast on Tuesday and wave heights trend higher, a moderate
may be needed.
In addition, water levels may touch minor flood thresholds across
the most vulnerable NY Harbor, southern and eastern NYC/LI bays,
and W LI sound, locations over the next few days.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...BR/JT
NEAR TERM...JE/JT
SHORT TERM...JT
LONG TERM...BR/JT
AVIATION...20
MARINE...BR/JT
HYDROLOGY...BR/JT
TIDES/COASTAL FLOODING...