Mount Vernon, New York 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

038
FXUS61 KOKX 220259
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1059 PM EDT Wed May 21 2025

.SYNOPSIS...
Low pressure approaches from the Mid-Atlantic tonight and passes
just offshore Thursday into Thursday night. The low will weaken
over the Canadian Maritimes this weekend, allowing high
pressure to briefly build in for the beginning of next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
The forecast is generally on track. An area of widespread
showers across southern CT and eastern Long Island will continue
to push east as another area across western NJ moves into
western portions of the forecast area within the next couple of
hours.

Low pressure center approaches from the south and rain will
continue to spread eastward across the area tonight. The rain
should pick up in intensity late tonight as an approaching low
level jet enhances upward forcing. Hydrologic impacts look to be
limited, especially with the lack of convective potential - see
the hydrology section for more details.

Breezy conditions with easterly winds for tonight, particularly
along the coast. Lows from the mid 40s inland to around 50 for
coastal areas.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
The low level jet shifts through the area during the morning into
early afternoon, taking the highest rainfall probabilities and
intensity with it. The surface low will however still be nearby to
our east in the evening, so rain chances continue across the area
with the highest chances over the eastern zones. Chances then
diminish during the late night hours with the low farther away to
the NE.

Clouds and rainfall will hold temperatures in the 50s during the
daytime with the northern zones likely not getting out the 40s.
NBM has been too warm in a cloudy/rainy regime lately, so went a
couple of degrees below it for highs. Low temperatures then
mostly in the 40s. 15-25 mph ENE winds in the morning gradually
back towards the north in the evening and diminish. Gusts 30-35
mph for the coastal areas during the daytime.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
A broad upr lvl low will become established over the Northeast on
Fri before translating into the maritimes by Sun.

Fri will be cool across the area with highs in the 50s and lower
60s. The cold pool aloft as well as cyclonic flow will allow for the
generation of shwrs thru the day, especially in the aftn when lapse
rates are steepest. With h85 temps dropping to around 1C, it would
not be surprising to see some low topped tstms across the area with
even some small hail.

It will be even colder aloft on Sat, so continued chances for the
generation of a few shwrs and low topped tstms. Drier air at the mid
lvls attm may limit coverage, but could aid in the production of
isold downburst wind gusts in convection. Better mixing on wly flow
is progged to produce warmer daytime highs despite the colder
airmass overall. Highs in the 60s per the NBM.

The fcst for Sun is dry, although the 12Z GFS has a shrtwv ripping
thru the cwa producing more sct shwrs. Stuck with the blended
approach of the NBM until this feature is resolved with more
confidence. Warmer yet on Sun with highs in the upr 60s.

Warmer again on Memorial Day, although the current progs per the
NBM still keep high temps aob normal in the low 70s. With weak high
pres ridging across the cwa, generally dry attm, although the fcst
brings in very slight chances by the end of the day srn areas as
the next sys approaches.

The next sys is timed for Tue into Wed in the form of a Gulf primed
weak low driven by the upr flow and sparked by convection over the
cntrl CONUS. Stuck with the NBM, with another down-tick in temps due
to the expected clouds and rain.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Weak low pressure will remain near the lower Great Lakes, while a
second low develops near the southern Mid Atlantic coast. This
second low will then move north, passing just south of Long Island
on Thursday and just east Thursday night.

MVFR cigs with some light rain and E-ENE flow 10-15G20kt should
persist into this evening. As the low to the south develops, IFR
cigs develop mainly after midnight and rain becomes moderate to
locally heavy in intensity, while winds increase to 15-20G25kt and
back NE. A return to MVFR looks to occur Thursday afternoon, with
slow improvement toward VFR through the end of the TAF period.

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

Amendments likely mainly for changes in flight categories.
Gusts may be more occasional than frequent through around
daybreak.

.OUTLOOK FOR 00Z FRIDAY THROUGH SUNDAY...

Thursday night: Improvement to MVFR likely and potentially low end
VFR. Winds backing NE-N 15G20-25kt.

Friday: Chance of showers with MVFR cond at times. N winds 10-
15G20kt E of the NYC metros Thu evening.

Saturday and Sunday: Mainly VFR. NW winds G15-18kt.

Monday: VFR.

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

.MARINE...
Small craft for all waters heading into tonight. Winds increase
overnight with gales on the eastern ocean waters late at night, then
over the eastern half of LI Sound as well as the eastern bays
starting Thursday morning. Gale warning now in effect for these
spots through Thursday afternoon. May need to extend the warning a
few hours into the evening based on trends of a stronger low passing
just east of the waters during Thurs evening. All current SCAs may
needed to be extended by few hours as well. Gusts to 35 kt possible
even over the ocean waters west of Fire Island inlet, but not
widespread enough for warning consideration.

A SCA will likely be needed on the ocean Fri-Sat, mainly for
seas. All waters look to be blw SCA lvls Sun and Mon. Seas may
then build on the ocean to SCA lvls late Tue.

&&

.MARINE...
Small craft for all waters heading into tonight. Winds increase
overnight with gales on the eastern ocean waters late at night, then
over the eastern half of LI Sound as well as the eastern bays
starting Thursday morning. Gale warning now in effect for these
spots through Thursday afternoon. May need to extend the warning a
few hours into the evening based on trends of a stronger low passing
just east of the waters during Thurs evening. All current SCAs may
needed to be extended by few hours as well. Gusts to 35 kt possible
even over the ocean waters west of Fire Island inlet, but not
widespread enough for warning consideration.

A SCA will likely be needed on the ocean Fri-Sat, mainly for
seas. All waters look to be blw SCA lvls Sun and Mon. Seas may
then build on the ocean to SCA lvls late Tue.

&&

.HYDROLOGY...
Total rainfall for this event through Thursday night is expected to
range mostly 1-2 inches with up to 2.50 inches possible over eastern
Long Island and Southeastern CT. The intensity and duration of the
rain are however not high enough for flash flooding concerns. Only
some minor nuisance urban related/poor drainage flooding will be
possible, and mainly just during Thursday, so overall impacts should
be low to none.

No hydrologic impacts are expected Fri-Wed.

&&

.TIDES/COASTAL FLOODING...
A prolonged E-NE flow continues into Thursday afternoon, backing
N/NE Thursday afternoon and evening. This backing of winds
should help limit the magnitude of coastal flooding for most
areas, but potentially enhance impacts along Peconic and
Gardiners Bay and north shore of LI.

Localized minor coastal flooding possible with the early Thu AM
high tide along western GSB.

The latest forecaster adjusted Stevens (75th percentile
weighting), ETSS, PETSS STOFS guidance blend signals widespread
minor coastal flooding for the south shore of Nassau County, the
twin forks of LI (localized moderate impacts possible for north
facing areas along the bayfront), and along much of LI Sound.

Localized minor coastal flooding likely for NY/NJ harbor where
winds will back to the N/NNE earlier. Magnitude of coastal
flooding for central and eastern great South Bay, Moriches, and
Shinnecock bays will depend on tidal piling trends, but looks to
be localized here.

For Fri evening high tide, coastal flooding looks to be more
localized for the Fri eve high tide cycle, to southern Nassau
and SW CT, in response to offshore flow and subsiding onshore
swells.

Potential for localized coastal flooding Sun into early next
week with approach of new moon, causing areas to need as little
as 1/4ft of tidal departure for minor coastal flooding.

As far as shoreline impacts, along the north shore of the south
fork of Long Island, breaking waves of 1 to 3 ft may cause dune
erosion and localized washovers, as well as enhance splashover
and flooding onto shoreline roads and properties. Along the
ocean front and Orient Point, breaking waves of 4 to 6 ft on an
east to west sweep will result in beach erosion and beach
flooding during the times of high tide. Localized dune erosion
is possible. Along the north shore of Long Island, breaking
waves of 3 to 4 ft will cause dune erosion, localized washovers,
as well as enhance splashover and flooding onto shoreline roads
and properties.

&&

.CLIMATE...
Record minimum maximum (coldest high temperatures) are possible
for Thursday, May 22nd. Here are the records and forecast high
temperatures for the date:

NYC: 54/1894, forecast high: 53
JFK: 55/1967, forecast high: 53
LGA: 57/2003, forecast high: 53
EWR: 56/2003, forecast high: 53
BDR: 54/2005, forecast high: 51
ISP: 54/2003, forecast high: 54

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from 6 PM to 10 PM EDT Thursday for
     CTZ009>012.
NY...Coastal Flood Advisory from 6 PM to 10 PM EDT Thursday for
     NYZ071-073-078-176-177.
     Coastal Flood Advisory from 2 PM to 11 PM EDT Thursday for
     NYZ079>081-179.
     Coastal Flood Advisory from 2 PM to 7 PM EDT Thursday for
     NYZ178.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ331-332-
     340.
     Gale Warning from 6 AM to 6 PM EDT Thursday for ANZ331-332-340.
     Small Craft Advisory until 6 PM EDT Thursday for ANZ335-338-
     345.
     Small Craft Advisory until midnight EDT tonight for ANZ350-353.
     Gale Warning until 6 PM EDT Thursday for ANZ350-353.
     Small Craft Advisory until 6 AM EDT Friday for ANZ355.

&&

$$

SYNOPSIS...JMC/JC
NEAR TERM...JMC/JC
SHORT TERM...JC
LONG TERM...JMC
AVIATION...JP
MARINE...JMC/JC
HYDROLOGY...JMC/JC
TIDES/COASTAL FLOODING...
CLIMATE...