Southampton, New York 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

629
FXUS61 KOKX 291831
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
231 PM EDT Sun Jun 29 2025

.SYNOPSIS...
A cold front slowly drifts south of the area and brief weak high
pressure builds in behind it. The aforementioned boundary then lifts
north as a warm front late Monday into Monday night, followed by a
cold frontal passage Tuesday night. Weak high pressure will be
in control mid week. A cold front approaches and moves through
late Thursday into Thursday night, followed by high pressure
returning Friday into next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
A cold front south of the area continues to slowly drift south
tonight as brief weak high pressure builds in from the north. Aloft,
the flow remains mainly zonal tonight.

Any cloud cover around this afternoon should dissipate or push
south, leading to clear skies for tonight. Combined with light winds
expecting decent radiational cooling conditions so went with MOS
consensus for low temperatures. This may also allow for some
patchy radiation fog in the early morning hours. Confidence is
low at this time.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Heights rise at least the first half of Monday with shortwave upper
level ridging ahead of a digging trough over the Mid-West. Weak high
pressure over the area dissipates and a warm front approaches from
the south. This warm front is expected to push north of the area
sometime late Monday into Monday night. We will be warm sectored
Monday until a pre-frontal trough and cold front swing through late
Tuesday into Tuesday night.

Much of Monday remains dry with partly cloudy skies. Late in
the day as the warm front approaches, isentropic and mid-level
shortwave lift could bring some showers to the area. Chances for
this linger into Tuesday morning. Plenty of elevated
instability is still seen in forecast soundings and kept thunder
chances in during this time.

Depending on what time the warm front pushes north, much of Tuesday
morning/early afternoon should actually be dry. There is some
uncertainty also in how much we can break out, but given we`ll
be in the warm sector and some hints from forecast soundings
there will likely a be brief period Tuesday morning with mostly
sunny skies. Forecast soundings also show decent mixing on
Tuesday (with the NAM even mixing up to 850mb). This gave enough
confidence to lower NBM Tds that usually have a higher bias
anyway. Thinking with the mixing we likely top out with Tds in
the lower 70s. High temperature forecast remained the same, but
given lower Tds now have lower heat index values and we likely
fall short of the 1 day Heat Advisory criteria of 100. However,
this will need to be monitored as Tds can still trend back up.

Heights start to fall more rapidly aloft as we get into the late
Tuesday period. This combined with lift from an approaching pre-
frontal trough/cold front will spark showers and thunderstorms
likely somewhere just west of the area. Thunderstorms should have no
problem developing given plenty of CAPE. Using MLCAPE given the
deeper mixed layer shows a model consensus of about 2000 J/kg, which
can definitely end up being higher. This combined with decent
shear (0-6km bulk shear 30-35 kt) will likely allow some storms
to organize and become severe. At this time damaging wind gusts would
be the primary hazard, but the CAPE profile is deep and wide
enough to support large hail as well.

These showers and thunderstorms will likely produce heavy
downpours given an environment with 2-2.25 inches of pwat.
Early look at longer range CAMs do show potential for 1+ per
hour rainfall rates. However, storm motion is expected to be
fast and at this time minor urban and poor drainage flooding
seems more likely than flash flooding, but an instance of flash
flooding can not be completely ruled out.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
* Seasonably warm and humid through Thursday

* Less humid towards the 4th of July

A cold front is forecast to be situated just offshore beginning
Wednesday morning. There may be some lingering showers across Long
Island early Wednesday morning, but for the most part, the forecast
area will be dry. High pressure builds in behind it and will be in
control Wednesday through Thursday morning with dry conditions.
Humidity levels drop somewhat for Wednesday and Thursday as dew
points slowly fall into the low to middle 60s.

A cold front approaches Thursday and at this time NWP is indicating
some dynamics and frontal forcing with this boundary, enough for the
chance for thunderstorms for portions of the forecast area, with
highest chances across the Lower Hudson Valley. May have to bump up
POPs with next forecast package as ECMWF, GFS, and Canadian
deterministic models show more in the way of precipitation associated
with this cold front late Thursday as compared to previous forecast
runs. If this trend continues, showers and thunderstorms will be
more likely.

Lower humidity levels expected later in the week, towards the 4th of
July holiday and into the first part of the weekend with dew points
falling into the 50s and lower 60s by Saturday. Would not be
surprised to see even lower dew points as models typically have a
hard time handling humidity levels, especially in the long term.

Conditions are expected to remain mainly dry Friday into next
weekend with high pressure in control. Humidity levels climb
Saturday night as a warm front lifts north of the area. Slight
chance for showers and thunderstorms Sunday with the approach of
another cold front to the west.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A weak front and/or surface trough will remain across the
coastal terminals this afternoon before pushing south this
evening. High pressure will then build in from the NW tonight
into Monday.

VFR prevails.

The CT terminals, KJFK, and KISP will do battle this afternoon
as the seabreeze attempts to work in against a W-WNW flow.
Expect any seabreeze to have a west component this afternoon,
but KJFK may for a time go more southerly. Elsewhere, winds will
be W-WNW around 10 kt with a few gusts possible at 15-18kt.

The winds will then quickly lighten this evening and veer around
to the N/NE at less than 5 kt. In some cases, winds will just
go light and variable. Winds will then become SSE at 10 kt or
less on Monday.

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

Winds at KJFK may fluctuate from WSW-S this afternoon.

There is low-medium to chance for the seabreeze to make to KLGA
toward 23Z.

.OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...

Monday Afternoon: VFR during the day. A chance of showers and
thunderstorms at night. MVFR or lower possible at night as a
warm front approaches from the south.

Tuesday: Showers with a chance of thunderstorms with MVFR or lower
possible, especially afternoon and evening. SW wind gusts 15-20 kt
day into early eve.

Wednesday: VFR.

Thursday: Mainly VFR, but MVFR possible afternoon into early eve
with showers and thunderstorms possible.

Friday: VFR.

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

&&

.MARINE...
Sub SCA conditions expected up until Tuesday afternoon when a S/SW
strengthens. This is will likely only impact the ocean waters, with
5 foot seas and 25 kt gusts, but there is potential for the gust
forecast elsewhere to trend upward. Gusts likely die down Tuesday
night, but 5 ft seas linger into Wednesday morning.

The eastern ocean zone may start of Wednesday with 5 ft seas, but
will be diminishing through the day.  Sub-SCA conditions are
expected from Wednesday night through Sunday with a leak of any
strong pressure gradients over the region.

&&

.HYDROLOGY...
No hydrologic impacts are anticipated through Monday. A half inch to
inch of rain is currently forecast for Tuesday into Tuesday
night on average. Locally higher amounts are possible, and
there is at least a low chance for flash flooding to occur.
Minor poor drainage flooding would be more likely.

No hydrologic concerns thereafter.

&&

.TIDES/COASTAL FLOODING...
There is a moderate risk of rip current development across the
ocean beaches today and Monday.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JP/JT
NEAR TERM...JT
SHORT TERM...JT
LONG TERM...JP
AVIATION...DW
MARINE...JP/JT
HYDROLOGY...JP/JT
TIDES/COASTAL FLOODING...