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748
FXUS61 KOKX 192310
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
710 PM EDT Wed Aug 19 2026
.WHAT HAS CHANGED...
WPC has upgraded the excessive rainfall outlook to slight (level
2/4) for NYC metro and NE NJ Thursday afternoon and evening.
&&
.KEY MESSAGES...
1) Showers with embedded thunderstorms are expected on
Thursday. A period of moderate to heavy rainfall with isolated
to scattered instances of flash flooding is possible late
Thursday afternoon into the early evening.
2) Unsettled weather this weekend.
&&
.DISCUSSION...
.KEY MESSAGE 1...
A cold front slowly approaches tonight through Thursday and
will stall over or near the area through the weekend. The
persistent upper level trough over the eastern US continues
through this period as well. Shortwave energy currently over the
mid-West will round the base of this trough and aid in
development of a weak wave of low pressure that will pass near
the area. Forecast PoPs have increased to widespread likely with
categorical POPs across portions of NE NJ and NYC. Currently
CAMs show a timing between 2 pm and 8 pm for the bulk of the
precipitation, and probably more specifically between 5 pm and
8 pm, though there is still some uncertainty with timing and
track of the precipitation.
Despite unimpressive CAPE profiles and lapse rates that might
lead to less convection over the forecast area, warm rain
processes, high PWATs (1.5 to 2 inches) and lift associated with
the front seem to be more of the driving forces for the heavy
rain potential. However, there is still uncertainty among the
models, and while the cold front itself is slow moving, the area
of showers and thunderstorms looks to be progressive. A Flood
Watch will not be issued with this forecast package due to the
continued uncertainty. Forecast QPF is a bit higher than the
latest deterministic NBM with 0.75 to 1.25 inches for northeast
NJ, NYC and western Long Island and 0.25 to 0.50 inches
elsewhere. Isolated higher amounts are possible, especially for
northeast NJ, NYC and Long Island, upwards of 2 to 3 inches as a
worst case scenario right now.
The Weather Prediction Center has placed much of NE NJ, NYC,
southern Westchester, and Nassau county in a slight risk for
excessive rainfall, while much of the rest of the area is in a
marginal(except the Twin Forks of Long Island and SE CT).
While thunderstorms are possible, the severe potential is likely
farther south of our area. While shear values are impressive
(0-6km bulk shear of 45-50kt), the aforementioned weak/low CAPE
profile will be a limiting factor. The SPC has continued to
keep the marginal and slight risk south of our area.
.KEY MESSAGE 2...
The front looks to push farther offshore for Friday before
additional waves of low pressure pass nearby over the weekend.
There looks to be another period of potential moderate to heavy
rainfall, specifically during Friday night into Saturday
afternoon and evening. Once again, guidance is struggling with
timing, strength, and location of the offshore wave that will
form ahead of a negatively tilted upper trough. The Weather
Prediction Center has placed much of the area in a marginal
risk for on Saturday. Thunderstorm activity with this event is
expected to remain mainly offshore, although isolated thunder
along the coast can not be ruled out.
With the stalled front still offshore on Sunday, a cold front
approaches from the west. This brings a continued chance of
showers and thunderstorms Sunday.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
High pressure gives way to an approaching cold front tonight that
slowly moves across the terminals on Thursday. The front is likely to
push to the south Thursday night.
VFR through Thursday morning. Showers and thunderstorms are possible
for the afternoon and early evening. PROB30 groups for TSRA are in
place for the NYC terminals beginning at 18z Thu and carry through
to about 01z Fri. Probabilities are lower for thunder at KSWF, KHPN,
KBDR, and KGON, so have just gone with a PROB30 for SHRA at these
more northern terminals. Otherwise, RA should prevail by the start
of the Thu evening push and taper towards 02-03z Fri.
Winds weaken this evening, becoming WNW-NW and light mainly under 5
kt late tonight. Winds should then become N-NE Thursday morning and
remaining light. The flow likely remains weak on Thursday, so winds
may vary from some from TAFs at times. Winds likely shift more N and
NE Thursday evening.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Some amendments may be needed for wind direction changes this
evening.
Adjustments likely for timing of TSRA potential Thursday afternoon
and evening. The PROB30 may need to become a TEMPO if confidence
increases.
Low confidence with wind direction on Thursday, but speeds remain
light.
.OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
Thursday night: MVFR or lower possible in showers and t-storms
during the early evening. Highest chance for thunderstorms are NYC
metro and Long Island during the first half of the evening.
Friday: Mainly VFR. Low chance of showers with MVFR or lower.
Saturday: Chance of showers with MVFR or lower at times.
Thunderstorm possible in the afternoon/evening.
Sunday: Chance of showers, possibly a thunderstorm, with MVFR or
lower at times.
Monday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Sub-SCA conditions currently forecast through the start of next
week. There is a low chance for forecast winds and waves to trend
higher depending on location and strength of a wave of low pressure
on Thursday evening.
Rip Currents: With winds largely less than 10 kt and weak swells at
or under 2 ft, there is a low risk of rip currents through at least
the first half of Friday. Increasing E flow parallel to the
shoreline could increase the risk to moderate by late Friday
afternoon.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
DISCUSSION...JP
AVIATION...JE
MARINE...JP
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