892
FXUS61 KOKX 010815
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
415 AM EDT Tue Sep 1 2026

.WHAT HAS CHANGED...
Day 1 Convective Outlook from SPC has expanded the slight risk
of severe thunderstorms east into Fairfield county in SW CT and
Nassau county on western LI.

The best chance for severe weather will be late this afternoon
into early this evening.

&&

.KEY MESSAGES...
1) Isolated to scattered strong to severe thunderstorms late
this afternoon into early this evening across much of the area.
Greatest threat will be across western LI, SW CT, NYC, NE NJ,
and the Lower Hudson Valley.

2) After a lull in shower and thunderstorm activity Wednesday,
more showers and thunderstorms forecast Wednesday night through
Thursday night.

3) Drier conditions expected for the holiday weekend.

&&

.DISCUSSION...
.KEY MESSAGE 1...
Warm advection showers across the area this morning, mainly for
LI and southern CT, will work east and offshore by around 7 or
8 am. Hourly rainfall rates of 0.50 to 0.75" have been noted
with this area as it works east. Minor, poor drainage flooding
is possible.

Additional showers forming across northern NY state this
morning, aided by stronger dynamics, will mainly impact New
England late this morning into this afternoon. Some of this
activity is likely to impact portions of southeast CT and
far eastern LI. There airmass across these locations will be to
stable to support severe thunderstorms.

The main focus of concern will come this afternoon into early
this evening. A warm front will lift north of the area this
morning, but only for a brief time. Strengthening high pressure
across eastern Canada into New England will send the front back
to the southwest as a backdoor cold front late this afternoon
into this evening. Winds will back around to the east behind it.
While there is some uncertainty as to how much the airmass will
destabilize in the warm sector today, HREF mean SBCAPE values
are still 1000-2000 J/KG across the marginal and slight risk
areas. Greatest instability will be north and west of the NYC
metro. Additionally, there is 40-50kt of deep-layer shear and
decent directional shear 0-3km. SPC has included part of the
area in a low probability for tornadoes (less than 5 percent).
However, mid-level lapse rates are marginal around 6C.

The flood threat remains low with the area under a marginal risk
of excessive rainfall. This is for an isolated flash flood
threat. While the airmass is loaded with moisture, PW values
around 2 inches, there is decent storm motion in the westerly
flow aloft. Training does not seem likely in this event. SPC
HREF probabilities are greater than 50 percent for an 1" in 3
hours, but less than 10 percent for 3" in 3 hours.

Much of the strong to severe convection should drop south and
west of the area around or shortly after 00Z (8 PM).

.KEY MESSAGE 2...
An easterly flow will result in a much more stable airmass
across the area on Wednesday. The frontal boundary is expected
to stay south and west of the region before starting to move
back in Wednesday night into Thursday as a warm front. SPC has
the western half of the area in a marginal risk for severe
weather, mainly due to some uncertainty with how far south and
west the front gets. Right now, expecting mainly scattered
showers for the western half of the forecast area.

Greater coverage of showers and thunderstorms is expected
Wednesday night into Thursday morning with the warm front
lifting across the area. The airmass will then warm up and
destabilize Thursday in the warm sector with another chance of
strong to severe convection with the cold front late Thursday
afternoon/evening. SPC has western portions of the area under a
marginal/slight risk and WPC has the entire area under a marginal
risk of excessive rainfall. Details should fall better into
line in the next 24h.

.KEY MESSAGE 3...
A drier pattern will set up Friday into the holiday weekend.
High pressure begins to build in from the north. Mainly dry
conditions are expected. Temperatures are not expected to
deviate too much from normal. Less humid conditions are also
forecast.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
A warm front approaches from the south overnight and stalls over
the region during Tuesday. The front will then likely move just
south of the area Tuesday night.

SHRA continue to move through the area, becoming more scattered
with drizzle in between. MVFR and localized IFR or lower cigs
have overtaken much of the area and should remain in place
through at least mid-morning where some improvement for SW
terminals (NYC) is expected, possibly becoming VFR once again in
the afternoon. Outlying terminals may remain MVFR or IFR
through the day. IFR becomes more likely once again Tuesday
evening for all terminals. TSRA becomes possible as well as
early as 16Z but more likely 18Z-00Z.

Light winds overnight and variable at times through Tuesday. During
the day Tuesday the sfc front may get into southern portions of the
area, resulting in more of a S/SW flow for most terminals.

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

Variability in wind direction can be expected thru the TAF period,
especially on Tue with a front in the vicinity.

There is the potential for IFR for portions of the day Tuesday.

.OUTLOOK FOR 09Z WEDNESDAY THROUGH SATURDAY...

Tuesday night-Wednesday: A chance of thunderstorms Tuesday evening.
MVFR or lower possible with periods of rain.

Thursday: MVFR or lower at times with chances for showers and tstms.

Friday: Mainly VFR. A period of MVFR or lower possible in SHRA.

Saturday: VFR.

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

&&

.MARINE...
The pressure gradient across the waters this week is not
expected to be that steep. Mainly below SCA conditions are
forecast. Marginal SCA conditions for eastern parts of the ocean
forecast late tonight into Wednesday in a strengthening
easterly flow.

Rip Currents:

There is a low risk for rip current development today with
light winds and low swells under 2 ft. The risk increases to
moderate on Wednesday with 3 to 4 ft E swells at a 7 sec period,
and NE winds 10 to 15 kt developing by late afternoon.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

DISCUSSION...DW
AVIATION...MW
MARINE...DW