Groton, Connecticut 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

147
FXUS61 KOKX 101724
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
124 PM EDT Tue Jun 10 2025

.SYNOPSIS...
A wave of low pressure moves across early today and then north of
the area this afternoon into this evening. An associated cold front
moves across this evening. Weak high pressure will be across the
area for the rest of tonight through midweek into Thursday. Another
cold front passes through Thursday night into early Friday and then
becomes nearly stationary near the region into early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Patchy dense fog followed by heavy showers and thunderstorms will be
the main hazards with the forecast today.

Patchy dense fog likely across coastal sections through the first
half of this morning, especially across Long Island and along the
coast of Connecticut. Rest of the area will still have fog,
patchy in coverage. Patchy drizzle is expected also.

The heavy showers and thunderstorms will be enhanced with forecast
increases in low level omega into this morning and then with
increasing instability with daytime heating this afternoon. Drier
air infiltrating in the low to mid levels may very enhance downdraft
and lead to gusty winds with thunderstorms, with a marginal risk for
severe downbursts of wind.

A marginal flood threat exists with these thunderstorms as well. See
hydrology section for more details on that.

Synoptics, mid level trough moves in with lowering heights today. At
the surface, a wave of low pressure approaches from the DelMarva
into this morning. The center of this low traverses the local region
late this morning into early afternoon before passing north of the
region. An associated cold front moves across this evening. Ahead
and along the cold front, there will be potential for more showers
and thunderstorms but overall convective coverage is expected to be
less than convective coverage in the morning.

Abundance of clouds and the rain in the forecast will limit
temperatures today. Forecast highs used consensus of short term
guidance, ranging from the mid 60s to upper 70s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
For tonight, early in the evening, still have a chance of showers
and thunderstorms across portions of the region around NYC and
locations north and west. Slight chance of showers and thunderstorms
elsewhere.

Overall, a more westerly flow sets up in the low to mid levels of
the atmosphere from late this evening through Wednesday. Flow in the
mid levels transitions to nearly zonal flow with gradually rising
heights while at the surface, a cold front moves east of the region.
Weak high pressure builds in thereafter. Center of this high
pressure area remains to the south and east of the area.

Dry conditions are expected after 8PM tonight and through Wednesday.
Lows tonight exhibit more variance, as more radiational cooling is
expected with the decreasing clouds and light winds. For Wednesday,
more sun is expected along with a continued westerly flow, likely to
back around to more southerly direction along the coast with sea
breeze influence. Forecast highs rebound into the low to mid 80s,
approximately 5 degrees above normal for this time of year.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Long term forecast updated with latest national blend of model
dataset. Still overall an unsettled weather pattern taking shape
for Friday, the weekend and into early next week with chances of
showers and thunderstorms. Model uncertainty still present with
stalled front placement differences between models. Previous
discussion follows.

The long term forecast period will be dominated by a mid and
upper level trough, mainly across eastern Canada, and into
Northern New England, with nearly zonal flow across the Midwest,
and into the Northeast, and Mid Atlantic region. Global
guidance is fairly similar through the extended period. A cold
front is forecast to move through the region late Thursday night
into early Friday morning, and then become nearly stationary to
the south of the area, through the Mid Atlantic region and the
Delmarva, into early next week. There is some uncertainty as to
how far south the frontal boundary will setup. The will affect
the track of waves of low pressure that are forecast to track
along the boundary. And some guidance that the front may drift
farther south late in the weekend into early next week. Also,
the placement of the boundary will affect temperatures, mainly
Saturday through Monday, with more uncertainty in highs and low
seen in the spread of possibilities with the NBM guidance. As a
result of the uncertainty, and no targets of opportunity, have
stayed close to the NBM deterministic guidance.

&&

.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
A cold front moves through this evening. Weak high pressure
builds in thereafter.

Continued improvement is expected with VFR for NYC terminals and
west by the late afternoon. A few hours later for BDR and ISP
and likely not until this evening for GON.

Shower and thunderstorm activity is now mainly east of NYC. A
cold front then approaches this evening bringing another chance
of showers and thunderstorms, with isolated coverage at best.
Pushed back timing of VCTS for NYC terminals to around 23-02z.
Showers and thunderstorms will weaken as they head farther east.

Winds will primarily be light from the E to ESE until the front
approaches from the west this evening, allowing winds to shift
to the W to SW, then W to WNW after 00Z (later for eastern
terminals. The flow will be weak, and winds may go light and
variable across most, if not all terminals tonight. Sea breeze
on Wednesday for at least JFK, ISP, BDR and GON. Confidence is
low at this time for other terminals.

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

Amendments likely throughout the entire TAF period for changing
flight categories.

Showers and thunderstorms are possible again in the early
evening hours. Timeframe is between 23Z Tue-02Z Wed. Coverage is
expected to be very isolated.

.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...

Wednesday - Thursday: VFR with gusty W flow.

Friday: VFR except in scattered showers and thunderstorms.

Saturday - Sunday: MVFR cigs or lower likely with chance of
showers.

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

&&

.MARINE...
Marine dense fog advisory remains until NOON with consistent
indications of lower visibilities less than 1 mile from multiple
runs of the HRRR. Before bulk of rain gets to the region, will
have moisture laden boundary layer. Enough mixing is expected
with the heavier rain showers later this morning to make any
dense fog by that point more patchy.

Otherwise, SCA conditions develop tonight into Wednesday morning
over parts of the ocean, east of Fire Island Inlet. Otherwise
sub-SCA conditions are forecast for rest of ocean and non-ocean
waters for the short term through Wednesday. For Wednesday
afternoon, all waters forecast to be below SCA.

With a weak pressure gradient force expected across the forecast
waters, as a frontal boundary remains in the vicinity of the ocean
waters, winds and seas are expected to remain below SCA levels
thereafter through the rest of the week.

&&

.HYDROLOGY...
Marginal flood threat with showers and thunderstorms through
today, especially this morning when convection is expected to be
of greater areal coverage. Layer precipitable waters reach near
1.5 to almost 2 inches along the coastal sections. Heavy
downpours will be likely, especially with any thunderstorms.
Chance of minor flooding with isolated flash flooding a
possibility also for urban, low lying and poor drainage areas.

Areal rainfall amounts are forecast to be near half to three
quarters of an inch with locally higher amounts possible.

No hydrologic impacts are expected thereafter through next
Monday.

&&

.TIDES/COASTAL FLOODING...
For the ocean beaches the moderate risk for the development of
rip currents remains for today with increasing southerly winds
and building surf this afternoon.

For Wednesday: the moderate rip current development risk
remains for the ocean beaches of New York City, and Nassau
county. There is a chance that the threat increases to high for
the Nassau ocean beaches with increasing southerly flow. And
for the Suffolk county ocean beaches the rip current risk is
forecast to be high.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 2 PM EDT this afternoon for ANZ331-
     332-335-338-340-345-350-353-355.
     Small Craft Advisory from 8 PM this evening to noon EDT
     Wednesday for ANZ350-353.

&&

$$

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