North Hempstead, New York 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

018
FXUS61 KOKX 031145
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
745 AM EDT Sat May 3 2025

.SYNOPSIS...
A slow moving cold front will approach this afternoon and
evening, then lift back north tonight as a warm front. A large
sprawling low pressure system over the Ohio Valley and high
pressure out over the Atlantic will then combine to bring
unsettled conditions beginning this weekend. The low will move
across Tuesday night into early Wednesday, then pass to the
northeast later next week, with associated frontal boundary
remaining not too far away.

&&

.NEAR TERM /THROUGH TONIGHT/...
Today is starting off partly to mostly sunny with a canopy of
thin high clouds and some patches of mid level clouds mainly
inland. Sunshine should allow temps to quickly climb to the
lower 80s across a good deal of the interior and into the 70s
across Long Island and southern CT. As the front to the west
begins to approach showers/tstms will become numerous north/west
of NYC. A corridor of moderate instability with MLCAPE 1500
J/kg will be in place across the Hudson Valley and NW NJ, with
low level SW flow increasing to 25 kt and mid level flow up to
45 kt, providing ample ingredients for strong to severe
thunderstorms inland NW of NYC this afternoon mainly after 18Z.
SPC forecasts a slight risk for areas along/NW of I-287, with
damaging winds and some large hail the primary concerns.
A marginal tornado risk also exists given the stronger low
level SW flow, but think this would be isolated/conditional at
best, depending on channeled S low level flow up the river
valleys to help increase low level helicity. A marginal flash
flood threat also exists in this corridor, as training of cells
may also occur as the low to mid level flow aligns with the
frontal boundary. Localized rainfall amounts of 1-2+ inches
look possible per 00Z HREF PMM QPF.

Even though chances for tstms increase late today into this
evening down into the NYC metro area, western Long Island and
southern CT as the front sags SE, the threat for svr wx is more
marginal there as fcst soundings do not look as unstable, and
more of a marine influence will exist due to S flow along the
coast. In fact, southerly sea breezes should gust to 25-30 mph
during mid to late afternoon along the south shore of Long
Island, and to 20-25 mph across southern CT.

Convection should wane during the late evening and overnight,
and the frontal boundary should retreat back to the north as a
warm front overnight. Some patchy fog may be possible where
earlier heavier rainfall occurred. Low temps will fall to the
lower 60s in NYC and NE NJ, and into the 50s elsewhere.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
On Sunday look for clouds to linger with a S-SE onshore flow
ahead of the low to the west. Rain chances increase especially
during the afternoon/evening as an Atlantic moisture feed sets
up between the low to the west and offshore high pressure, with
the best chances for heavier rain late Sunday night into Monday.

With onshore flow and thicker cloud cover temps will not be as
warm, with highs both days in the 60s to lower 70s, and lows
Sunday night in the 50s.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The region remains in a rainy weather pattern overall during the
long term. Rain is not expected the entire timeframe but at
least chances for rain appear for each time period Monday night
through Friday. Instability and forcing make for chances of
thunderstorms as well within the Monday night through midweek
timeframe. Relatively highest chances of thunderstorms are
forecast on Tuesday into early Tuesday evening.

Cutoff upper level low continues to approach the region Monday
night through Tuesday night. This upper level low eventually
exits east of the region Wednesday into Wednesday night.
However, another upper level trough moves into the region behind
the low going into late week.

At the surface, a frontal boundary remains within the region
Monday night into Tuesday. Low pressure center associated with
this frontal boundary will be approaching the area as well.
Would expect a greater amount of vertical forcing as a result.

The low pressure center itself moves across Tuesday night into
early Wednesday. The low then moves northeast of the region
towards late week. Vertical forcing will decrease Tuesday night
into Wednesday. However, synoptic lift becomes favorable once
again with another front moving into the region.

Temperatures average above normal during the long term period.
Relatively warmest day is on Wednesday and Thursday when
forecast high temperatures reach the upper 60s to lower 70s for
much of the region.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Stalled frontal boundary within the region for the TAF period.
Showers are forecast during the TAF period, with highest chances
for the late afternoon and evening. There will chances of
thunderstorms as well for the same general timeframe as the
highest chances of showers.

Otherwise, mainly VFR conditions are expected with possible MVFR
with any shower activity. A greater overall chance of MVFR is
forecast early Sunday.

Winds are forecast to generally remain southerly through the TAF
period, mostly near 5-10 kts. Higher winds forecast for
afternoon into early evening with wind speeds closer to 15 kts
and gusts near 20-25 kts.

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

Amendments are likely to refine the timing of showers and
thunderstorms.

Start and end time of gusts could be a few hours off from TAF.

IFR possible early Sunday.

.OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...

Sunday: Mainly MVFR early, possible IFR. Otherwise, mainly VFR
with chance of MVFR or lower in showers. Best chance will be in
the afternoon and nighttime hours. Slight chance of
thunderstorms.

Monday: Showers likely with MVFR or lower expected. A slight
chance of tstms. E winds G15-20kt.

Tuesday: Showers with MVFR or lower expected. A chance of
thunderstorms. SE winds G15-20kt day into early eve possible.

Wednesday: Chance of MVFR or lower with a chance of showers and
slight chance of thunderstorms.

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

&&

.MARINE...
SCA conditions expected for the ocean from mid afternoon into
tonight, with seas building to 5-6 ft on a long fetch S flow
increasing to 20 kt. A period of SCA cond also expected to the
south shore bays of Long Island as an enhances sea breeze gusts
up to 25 kt.

A brief window of SCA cond is also possible for the ocean W of
Fire Island Inlet late Mon afternoon into Mon evening, with E
flow gusting up to 25 kt and seas building to 5 ft.

&&

.HYDROLOGY...
A marginal flash flood risk exists for this afternoon/evening
for inland areas NW of NYC, as tstms there will be capable of
producing 1-2+ inches of rain in a short period of time. Most of
the impacts should be at nuisance level, but cannot rule out an
isolated flash flood event.

Rain could also be heavy at times from late Sunday night
through early Wednesday. With parallel flow from lower to upper
levels, training of showers and thunderstorms could occur.
Minor flooding will be possible for excessive runoff in low
lying, urban, and poor drainage areas.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 2 PM this afternoon to 8 PM EDT this
     evening for ANZ345.
     Small Craft Advisory from 2 PM this afternoon to 6 AM EDT
     Sunday for ANZ350-353-355.

&&

$$

SYNOPSIS...BG/JM
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...JM
AVIATION...JM
MARINE...BG/JM
HYDROLOGY...BG/JM