Smithtown, New York 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

444
FXUS61 KOKX 041958
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
358 PM EDT Sat Jul 4 2026

.WHAT HAS CHANGED...
A severe thunderstorm watch is in effect for parts of the area
through 11 PM tonight.

&&

.KEY MESSAGES...
1) One last day of dangerous heat and humidity expected today.

2) Severe thunderstorms are possible this afternoon and evening with
the main impact being potentially damaging winds. Flash flooding
chances are low.

3) Marginal to Slight risk of flash flooding from Sunday afternoon
through Monday night.

&&

.DISCUSSION...
.KEY MESSAGE 1...
Dangerous heat will continue into this evening. This level of heat
can be deadly for those without adequate cooling and hydration.
Impacts to transportation infrastructure (rail, bridge,
road/tarmac), electrical (high demand) and water systems (open
hydrants reducing water pressure) have been noted with previous heat
events of this severity and duration. On average, heat kills more
people than any other weather related hazard.

Heat Warnings and Advisories remain posted through this evening.
Heat indices overall lower than what was observed yesterday with RH
through the boundary layer dryer lower, allowing surface dewpoints
to mix out some more. Ambient temperatures for the most part have
been cooler as well. Relief is on the way for Sunday and Monday with
heat indices below advisory thresholds.

.KEY MESSAGE 2...
The Storm Prediction Center has placed western portions of the
forecast area in a Severe Thunderstorm Watch until 11 PM this
evening. A slight risk of severe thunderstorms is otherwise in
place for the rest of the forecast area. Showers and
thunderstorms are expected to push in/become more numerous
across the forecast area with sufficient MLCAPE and wind shear.
Aforementioned dryer boundary layer with more of an inverted-V
profile coupled with slightly stronger speed shear aloft lends
to the potential of wind gusts at least as strong as observed
yesterday. 6pm to 11pm tonight still appears to be the most
likely time for storms, but things can get going as early an
hour or two earlier.

The forward motion of storm cells should help mitigate flooding
impacts. Thinking is that any flash flooding would be isolated and
limited to more urbanized areas and minor urban/poor drainage would
be the more likely mode of flooding. WPC has a slight risk of flash
flooding for most of the forecast area.

.KEY MESSAGE 3...
A stalled front is progged to be nearby to our south Sunday into
Monday with a wave of low pressure forming along it and pushing
towards us Monday night into Tuesday. Flooding concerns increase
during this period with PWATs near 2 inches and the flow aloft
promoting the potential of backbuilding/training of cells. For Monday
and Monday night, lift and moisture convergence may be enhanced by a
low level jet developing along the north side of the approaching
low. Additionally, the position of a jet streak couplet aloft may
produce additional synoptic scale lift.

12z HREF ensemble probabilities indicate the eastern edge of a 30%
chance of 3 inches of rainfall in 3 hours very close to NE NJ Monday
night, a threshold that has been a pretty good indicator locally for
flash flooding occurrence. A 50-70% chance of an inch or more in an
hour covers NYC, NE NJ and the lower Hudson Valley for Monday night.
Trends will need to be monitored for higher confidence in the flash
flooding potential.

Current forecast rain amounts from Sunday through Monday night range
mostly 2 to 4 inches with the higher amounts over the western zones.
Due to a more convective nature, the rainfall, particularly over NE
NJ and NYC, during Sunday afternoon/evening may end up being lower
than what is currently forecast in the timeframe, so perhaps mostly
2-3 with locally 4+ inches would be a more likely scenario Sunday
through Monday night.

WPC has slight risk of flash flooding for Sunday and Monday from
roughly Fairfield and Nassau Counties and points west where forecast
rain amounts are generally higher. A marginal risk remains elsewhere
where lower amounts are anticipated and/or more rainfall can be
tolerated before flooding impacts would begin.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
A cold front approaches tonight and moves through the terminals
into Sunday AM.

VFR outside SHRA/TSRA. Continue to adjust timing of possible
Added TEMPO after 00z this evening for most likely timing of
convection. Still possible activity could pop up before this
and maintaining PROB30 after 22Z for city terminals. Brief wind
gusts above 40 kt possible with any thunderstorm. Activity
diminishes by 6Z Sun. Can`t entirely rule out sub VFR cigs on
Sunday, particularly in the morning. SHRA and TSRA chances
return beginning late Sunday afternoon, and added TEMPO for a
likely active evening.

A general WNW flow around 10 kt with gusts up to 20 kt possible
today away from coastal sea breeze influence, though direction
may be more variable at times between NW and SW at some
terminals. Winds back more to the SW at the coastal terminals
into late afternoon, or S/SSW at JFK. Winds look to be highly
variable this evening with the cold front nearby, this likely
persists into the Sun AM push. Light E/SE flow on Sunday under
10 kt.

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

Wind direction may vary between NW and SW at times into late day.

Locally higher gusts than what is indicated in the TAFs possible
today with the strongest tstms.

Amendments likely for the timing of showers and thunderstorms
this afternoon and night.

.OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...

Sunday: Sub VFR at times with showers and thunderstorms
late in the afternoon and overnight.

Monday and Tuesday: MVFR or lower with periods of showers and
possible thunderstorms. SE flow Monday becoming NW on Tuesday.

Wednesday: VFR. N wind turns S in afternoon.

Thursday: VFR. Light S flow.

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

&&

.MARINE...
Sub-advisory conditions continue through the rest of the weekend.
Wind and seas build on Monday with the approach of a wave of low
pressure. Onshore wind gusts probably reach advisory thresholds on
Monday and Monday night on the ocean and some of the non-ocean
waters. For the ocean, seas also build 4 to 7 feet. Continued
widespread SCA conds anticipated for Tuesday as well. Improving
conditions for Wednesday.

For the area beaches today, the risk of rip currents starts is
moderate. A low risk is expected on Sunday. An increasing onshore
flow should increase the risk back to moderate for Monday.

Rip Currents...

For the area beaches today, the risk of rip currents starts is
moderate. A low risk is expected on Sunday. An increasing onshore
flow should increase the risk back to moderate for Monday.

&&

.CLIMATE...
Record High Temperatures:

July 4:
KNYC: 102/1949
KEWR: 105/1949
KJFK: 101/2010
KBDR: 98/1949
KLGA:100/1949
KISP: 97/2010

Record High Minimum Temperatures:

July 4:
KISP: 76/2002


Record Precipitation:

July 6:
KEWR: 1.15/1958
KBDR: 0.75/2024
KJFK: 1.03/2005
KISP: 0.92/2006

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 9 PM EDT this evening for CTZ005>008.
     Extreme Heat Warning until 9 PM EDT this evening for
     CTZ009>012.
NY...Heat Advisory until 9 PM EDT this evening for NYZ067>070-081.
     Extreme Heat Warning until 9 PM EDT this evening for
     NYZ071>075-078>080-176>179.
     Air Quality Alert from midnight tonight to midnight EDT Sunday
     night for NYZ069>075-176-178.
NJ...Extreme Heat Warning until 9 PM EDT this evening for NJZ002-
     004-006-103>108.
     Air Quality Alert until 11 PM EDT Sunday for NJZ002-004-006-
     103>108.
MARINE...None.

&&

$$

DISCUSSION...JC
AVIATION...DR
MARINE...JC