Norwalk, Connecticut 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

114
FXUS61 KOKX 170810
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
410 AM EDT Sat May 17 2025

.SYNOPSIS...
A warm front pushes north this morning, followed by a pre-frontal
trough and cold front this afternoon/evening. A secondary cold front
passes through Sunday evening. Low pressure is slow to exit the New
England coast and surface troughing may linger over the area through
Monday night as high pressure gradually builds in from the
northwest. High pressure takes control Monday night into early
Tuesday night. A frontal system impacts the area Wednesday into
Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
The upper low currently located over the Great Lakes continues
approaching today, with multiple spokes of vorticity rounding the
trough. It is progged to be centered over northern NY by 6 AM
Sunday. At the surface, a warm front has pushed through and will
continue to move north this morning. Behind it, a pre-frontal trough
and cold front approach and move through this afternoon/evening.

The convection forecast continues to be tricky today. Once again,
ongoing broken line/MCS activity may reach western portions of the
area a few hours after sunrise. While the activity will be
weakening, there will be some MUCAPE available, enough to
continue the slight chance mention of thunder this morning. This
activity could have an impact on how unstable we can become
during the late morning/early afternoon which will in turn
impact any afternoon/evening thunderstorm and severe weather
potential. Latest consensus across the CAMs is we are able to
clear out enough to get MLCAPE values up as high as 1500 J/kg
this afternoon across northeast NJ, the Lower Hudson Valley and
interior southern CT. It looks like there will be two main
surface triggers for convective initiation, in the afternoon
along a pre-frontal trough and then later in the evening along
the actual cold front. There will also be support aloft with the
lowering heights as the trough approaches. With 1500 J/kg of
MLCAPE and 35-40 kt of 0-6 km bulk shear, some organized
convection is possible to produce severe weather. While this
threat can not be totally ruled out for the whole area, the
current thinking is the greatest chances (although still low)
will be across northeast NJ, the Lower Hudson Valley and across
interior southern CT. The main threat is the potential for
damaging winds and large hail, but given decent low level
curvature in model hodographs, a quick isolated tornado can not
be completely ruled out, mainly across interior southern CT.

NBM was used of for T and Td today giving highs in the upper 70s to
mid 80s for most and Tds reaching the mid to upper 60s. Winds
increase today and forecast wind gusts were increased a bit with the
NBM90th percentile across northeast NJ, NYC and the Lower Hudson
Valley where the mixed layer is expected to be a bit deeper. Gusts
up to 30 mph are possible this afternoon.

The cold front pushes through likely just before or around midnight
and will finally start to filter in a drier airmass in a westerly
flow.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The upper level low will be centered to our north most of Sunday as
it very gradually shifts east. Some energy rotating around the low
will aid in pushing a secondary cold front through the area in the
evening hours. Some light rain showers are possible with this
feature, mainly across the interior. No thunder is forecast. Skies
also likely fill in around 4 kft, leading to mostly cloudy
conditions for the afternoon. In the cooler airmass, highs are
forecast to be in the upper 60s to lower 70s.

Surface troughing could continue into Monday as the low lingers off
the New England coast. Dry and sunny conditions are expected with
similar high temperatures as Sunday.

Both days could be gusty with some deeper mixing each day. 25 to 30
mph gusts are expected.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Key Message:

 * A frontal system likely impacts the region beginning   Wednesday,
and continues into Thursday, and possibly into Friday.

No significant changes were made to the forecast for Tuesday into
the end of the week, as a frontal system remains likely to impact
the region late Tuesday night into Friday. An upper closed low
develop over the mid section into the upper Midwest by late Tuesday
night, and then the upper trough deepens and the closed low and
upper trough are slow to move eastward into the beginning of next
weekend. At the surface a deepening low moves out of the Mid
Mississippi Valley and into the Ohio Valley late Tuesday into
Wednesday. This low then moves slowly across the northeast Thursday
into Friday in association of the upper low becoming nearly
stacked. With a secondary surface low developing late Wednesday
into Wednesday night and increased precipitable waters values and
lift, there is the potential for a period of moderate rainfall.
Also, depending on the track of the low Thursday`s temperatures are
more uncertain. However, overall temperatures will be near or slightly
below normal levels Tuesday through Friday.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
A warm front remaining just south of the region at 07Z will
advance slowly northward early this morning, and move north of
the terminals today. A cold front follows for late this evening.

Conditions have been slow to lower at the NYC terminals and west,
while to the east IFR to VLIFR in stratus and fog is widespread.
Uncertainty remains as to the timing and how far west IFR to LIFR to
develop through the remainder of the overnight. And KSWF may remain
MVFR through the overnight. Condition improve quickly after sunrise,
especially across the inland terminals, and at the coastal terminals
VFR expected late morning into the afternoon. Showers and
thunderstorms may be more scattered by late afternoon into this
evening, and continued with the PROB30 for TSRA.

Light and variable flow becomes southerly early this morning, then
southerly winds pick up to 10-15kt with some gusts up to 20kt in the
afternoon. With a cold front passage late this evening winds shift
to the W/NW, and may become gusty late tonight.


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

Uncertainty with the timing of IFR to LIFR mainly KJFK and KLGA, and
uncertain of LIFR at KEWR and KTEB, which may be IFR into early
morning.

Tempo or prevailing vsbys of 1/4sm possible at KJFK from 08-12z Sat.


.OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...

Saturday night: VFR. W/NW winds G20kt.

Sunday: VFR. Slight chance of showers inland with MVFR possible. W
winds G20-25kt.

Monday - Tuesday: VFR. Monday NW winds G20-25kt day into evening.

Wednesday: MVFR or lower with showers likely, mainly at night. E
wind gusts 15-20 kt.

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

&&

.MARINE...
Latest observations show areas of dense fog across the LI Sound and
some patchy dense fog on all other waters. Marine Weather Statements
and Dense fog Advisories are in effect until 9 AM.

Sub-Small Craft Advisory conditions are expected for the most
part today. However, some nearshore gusts could reach 25 kt,
mainly in the NY Harbor and western LI Sound. Additionally, some
afternoon thunderstorms are possible and could create locally
higher winds and waves.

Winds pick back up on Sunday and a Small Craft Advisory is in effect
during the daylight hours. Gusts could reach 25 to 30 kt, with seas
over the ocean reaching 4-5 ft. There is potential for the SCA to be
extended through Monday as marginal conditions are expected.

Winds and seas remain below advisory levels on all the forecast
waters Tuesday into Wednesday. With the approach of a frontal system
during Wednesday and easterly flow will be increasing and by late
day SCA conditions may develop on the ocean waters. With the
increased and persistent east flow into Thursday winds and seas on
the ocean waters will likely be at SCA levels. As low pressure
tracks northeast of the area Thursday night a northerly flow
develops and winds diminish, however, ocean seas are likely to
remain elevated into Thursday night.

&&

.HYDROLOGY...
There are no hydrologic concerns through next week.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 9 AM EDT this morning for ANZ331-332-
     335-340.
     Small Craft Advisory from 6 AM to 6 PM EDT Sunday for ANZ331-
     332-335-338-340-345-350-353-355.

&&

$$

SYNOPSIS...MET/JT
NEAR TERM...JT
SHORT TERM...JT
LONG TERM...MET
AVIATION...MET
MARINE...MET/JT
HYDROLOGY...MET/JT