Georgetown, Connecticut Weather Forecast Discussion

656
FXUS61 KOKX 062027 CCA
AFDOKX
Area Forecast Discussion...CORRECTED
National Weather Service New York NY
427 PM EDT Sat Sep 6 2025
.SYNOPSIS...
A cold front will move across this evening from northwest to
southeast. The cold front slows down on its southeast movement
late tonight as weak low pressure develops along it. The front
moves farther out into the Atlantic Sunday. High pressure
building in late Sunday into Monday will pass east of New
England on Tuesday, allowing an offshore wave of low pressure to
pass nearby Tuesday night into Wednesday. A cold front will
approach on Thursday and pass through Thursday night, followed
by Canadian high pressure Friday into Saturday.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Severe thunderstorm watch in effect until 8PM EDT this evening
for all land areas except New London CT and Suffolk NY. The marine
zones in this watch include NY Harbor and Western LI Sound. Main
threats with thunderstorms, frequent lightning, damaging wind
gusts, and heavy rain. Lesser chance but still probable, large
hail as well as a brief tornado.
The main factors, bulk shear 0-6 km AGL of 35 to 50 kt and right
rear quad of upper level jet, as well as surface CAPE near 3000
J/kg. CAPE lowers towards evening and will be lower throughout
for eastern half of Long Island and Southeast CT with more
marine influence through early evening. CAPE drops to less than
1000 J/kg by mid to late evening and shifts to south of Long
Island.
Expect the line of showers and thunderstorms to move through the
region into early this evening with some weakening as it moves
into the eastern half of Long Island and Southeast CT.
Thereafter, thunderstorm potential decreases this evening after
8PM with not much thunder expected at all overnight. Showers
will remain however with slower exit of the front and support
aloft from upper level divergence.
Lows in the upper 50s to lower 60s. Winds become more northerly
tonight.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
For Sunday, right rear quad of upper level jet remains near the
region, supporting synoptic lift. Despite the cold front being
southeast of the region, there will be enough moisture for rain
showers to remain across the region, especially early and
especially along the coast. The forecast has trended higher with
rain for Sunday compared to previously forecast. Forecast high
temperatures only in the upper 60s to lower 70s for Sunday.
Favorable lift area from upper jet shifts northeast of the
region Sunday night. Upper levels still have a trough across the
region but at the surface, high pressure will begin to build in
from the west. Drier conditions expected along with a decrease
in clouds. This will allow for more radiational cooling, with
forecast lows ranging from the mid 40s to upper 50s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
The period will start off with a longwave trough lifting across
eastern Canada on Monday, with confluence to its rear supporting
high pressure building over over the area through Mon, then passing
E of Tue. Heights aloft then rise along the coast into Tuesday as
the northern stream trough departs, while a shortwave trough along
the Southeast coast lifts northeastward along the periphery of the
offshore ridge. This wave should bring a chance of showers mainly to
Long Island and SE CT from late Tue night into Wed. As the longwave
trough becomes re-established over ern Canada later in the week,
this should send a dry cold front through Thu into Thu night, with
high pressure building from the NW in its wake.
Temps will be mostly a little below normal, with highs in the 70s
and lows mostly from near 60s in NYC to the mid 40s and 50s
elsewhere. The exception to this will be on Thu between passage of
the offshore wave and approach of the cold front, with highs in the
upper 70s/lower 80s, a little above normal.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
A cold front gradually moves through the area this afternoon through
Sunday morning. High pressure builds in Sunday night.
A line of showers and thunderstorms is moving slowly east across the
forecast area, affecting the metro terminals as of 20-22Z. This line
will continue to move east through the afternoon and evening
affecting the other more eastern terminals towards 20Z to around
22Z. IFR to MVFR conditions are possible in any
showers/thunderstorms. After about 22Z-23Z lingering the threat for
thunder diminishes for the metro terminals, but an isolated
thunderstorm is still possible through 00-01Z. The line is expected
to weaken as it pushes east, so as it reaches KGON, the chance for
thunder is lower but still possible, so PROB30 added for this
possibility. Wind gusts associated with any thunderstorms diminish
as the line moves east this evening.
Southerly flow continues today at 10 kt to 15 kt, with gusts 20 to
30 kt. As the front approaches later in the day and early evening
look for a wind shift, especially in any thunderstorms to the NW.
Additionally, gusts of 30 to 40 kt (or higher if storms become
severe - generally across NE NJ and Lower Hudson Valley) are
possible with any thunderstorms and added gusts of 30 to 35 kt
within the TEMPO groups for the +TSRA. Otherwise, with the boundary
settling nearby the winds likely go variable in direction late in
the TAF period for the city terminals this evening.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
There remains some uncertainty with the timing of the arrival of
showers and thunderstorms this afternoon with amendments becoming
increasingly likely late in the day and into the evening.
Gusts of 30 to 40 kt are possible with any of the stronger
thunderstorms today. If storms become severe gusts around 50 kt are
possible. Higher chances for severe are with KEWR and KTEB.
Start time of wind gusts may be off an hour or two.
.OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...
Sunday night: VFR.
Monday and Tuesday: VFR.
Wednesday: Potential for MVFR in -SHRA.
Thursday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
SCA remains for the ocean waters with marginal SCA wind gusts
on non-ocean waters. Most gusts near 20 kt but occasional gusts
near 25 kt especially along immediate coastline this afternoon
into early evening. Lesser gusts out across water and away from
shoreline, where low level temperature profile is more
inverted, limiting mixing. Further lowering of winds and seas
tonight through the rest of the weekend, with sub-SCA conditions
expected. Higher winds and seas within and near thunderstorms,
but thunderstorms should become less coverage by mid to late
this evening and even less overnight into early Sunday.
The sub-SCA conditions continue Monday and Monday night with
high pressure in control.
The pressure gradient will tighten Tue into Wed as an offshore wave
of low pressure passes by. E flow around 15 kt on Tue should
increase to NE 15-20 kt late Tue night into Wed, building ocean seas
to 5-6 ft from Tue night into Wed. There could also be a few gusts
up to 25 kt on the ocean late Tue night into Wed morning. Gusts/seas
on the non ocean waters should remain below 25 kt and 5 ft.
&&
.HYDROLOGY...
PWATS narrow corridor of near 2 inches ahead of cold front but
with higher speeds of the showers and thunderstorms, this will
limit the flooding potential. Main flooding threat will be minor
within the urban, poor drainage as well as low lying areas.
There is a low chance of flash flooding but not nearly enough
probability to warrant a watch.
With convection waning tonight, flood potential expected to
further lower but still could have some small areas of minor
flooding especially within the poor drainage areas.
Total rain amounts through Sunday near half inch to near 2
inches. Locally higher amounts possible.
No flooding potential expected for rain showers on Sunday. PWATs
will become considerably lower throughout the day.
Otherwise, no other hydrologic problems expected.
&&
.TIDES/COASTAL FLOODING...
There is a high rip current risk through this evening due to a
combination of a strong onshore flow (S 15-20kt) and southerly wind
waves of 4-5ft and 7 seconds. For Sunday, the risk at the very
least will be moderate, and possibly high with a southerly swell
of around 3 ft and 7 seconds. However, winds will be less of a
factor due to being offshore and generally less than 10 kt.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents until 8 PM EDT this evening for NYZ075-
     080-081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ350-
     353-355.
&&
$$
SYNOPSIS...BG/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...BG
AVIATION...JP
MARINE...BG/JM
HYDROLOGY...JM
TIDES/COASTAL FLOODING...

NWS OKX Office Area Forecast Discussion