Select NOAA-NWS Forecast Office Text Products
(Product availability varies with seasons, forecast office, and weather.)
Forecast Discussion for New York City/Upton, NY
To Select Another NWS Office Click on Map or Choose from List
|
| Select Forecast Office: | Select Product: |
848
FXUS61 KOKX 262341
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
741 PM EDT Wed Aug 26 2026
.WHAT HAS CHANGED...
A Flood Watch has been issued for Thursday between Noon and 11
PM for the Lower Hudson Valley, NE NJ, NYC, Nassau county and
Fairfield county.
&&
.KEY MESSAGES...
1) Confidence is increasing in a period of heavy rainfall and
scattered thunderstorms Thursday into Thursday night. Isolated
to scattered instances of flash flooding and strong to severe
thunderstorms are possible for parts of the area.
2) Dry and seasonable for the weekend ahead, with a warming trend
early next week.
3) High risk for rip currents on Thursday.
&&
.DISCUSSION...
.KEY MESSAGE 1...
Mid level open trough approaches the northeast early Thursday,
weakening as it does so. Surface low pressure with a slowly moving
frontal system accompanies this feature, and approaches the local
area by Thursday morning.
A warm front nears the region by early Thursday, with surface low
pressure well to the northwest. Southerly flow will begin to
increase this afternoon, with moisture advection commencing ahead of
this system and surface dewpoints reaching the low 70s by Thursday
morning. PWATs peak around 1.6-1.8" to just over 2" (depending
on which guidance you look at)by Thursday afternoon and
evening, which nears the max average for 8/27 per SPC`s sounding
climatology. Precipitation chances will increase through the
day on Thursday as the warm front approaches and lifts to our
north.
Heaviest precipitation, and thus threat for any flash flooding,
looks to occur Thursday afternoon and evening along a pre-frontal
trough that sets up along or northwest of the I-95 corridor. Most
12Z CAMs show an axis of precipitation setting up SW to NE somewhere
near NYC in the afternoon, but CAMs vary in coverage. Following
this, by late afternoon and evening a second axis of precipitation
will set up well N & W of NYC then traverse east, losing intensity
the farther east it traverses.
Areawide amounts should be around 0.5" to 1.5". Its very
possible areas far to the east receive very little, if any,
rainfall. The areas of highest rainfall amounts and thus highest
rainfall rates and greatest risk for flash flooding somewhat remains
uncertain. 12Z CAMs vary on where the heaviest axis of
precipitation will set up. Some bring the heaviest precip over
the LoHud and possibly NE NJ, others over NYC, Westchester,
Nassau, and Fairfield.
Given uncertainty in exact axis of highest precip, the 12Z HREF
shows a 25km neighborhood probability of exceeding 1"/hr rainfall
rates of 50 to 90% across NYC, NE NJ, Nassau, Fairfield, and LoHud.
The 12Z REFS appears to highlight similar areas for the highest
rainfall rate potential. However, given recent rainfall lowering
FFG and high enough confidence in higher rainfall rates
occurring, have gone with a Flood Watch for these areas. Flash
flooding is not anticipated to be widespread in all areas of the
watch, but confidence is high enough in the conditions for it
to occur in any area of the watch. Future CAM output will need
to be monitored for better agreement in the heaviest rainfall
location, so this can be better messaged. WPC has expanded their
Slight Risk (2/4) of excessive rainfall which now includes all
of LoHud and most of NE NJ, just scraping NYC.
Finally, thunderstorm chances also increase by Thursday afternoon
with model soundings showing both decent instability (~1500-2500
J/kg MLCAPE) and some shear, so cannot rule out isolated to
scattered severe thunderstorms. Wind gusts would be the main hazard
associated with the strongest storms, with DCAPE progged to be in
the 500-1000 J/kg. SPC maintains the marginal risk of severe
thunderstorms over NYC, but has expanded the SLight Risk (2/5)
for severe thunderstorms for areas N & W of NYC and has expanded
the Marginal (1/5) risk to include Fairfield and Nassau
counties. An isolated tornado or two can not be ruled out for
areas N & W of NYC. 12Z CAMs bring SigTor Parameters between 1
to 2 for areas of the LoHud given decent shear and helicity
values. SPC expanded a Slight (2/5) Risk for Severe Weather
across western portions of the area, becoming Marginal (1/5) for
NYC, Nassau, and Fairfield.
Instability rapidly drops by Thursday night with a quick end to
showers and thunderstorms.
.KEY MESSAGE 2...
Mainly zonal flow behind the late week system turns into weak
ridging by late Saturday into Sunday as heights aloft rise. Any
leftover shower activity from Friday should be well offshore by
early Saturday morning behind the frontal passage. Skies will clear
with northerly flow on Saturday, and dry conditions lasting into
Sunday. Winds turn southerly on Sunday as the sfc high shifts
offshore, and dewpoints climb a few degrees relative to Saturday.
Otherwise, near to slightly below normal temperatures both
days, with highs in the upper 70s to lower 80s. Heights continue
to build into early next week, with increasing temperatures.
.KEY MESSAGE 3...
Winds increase on Thursday out of the S closer to 15-20 kt. This
combined with a building swell of 3-4ft at 5s out of the S/SE will
bring a high risk of rip currents. The risk through much of the day
may end up being moderate for southeast Suffolk, but high is
possible by the late afternoon/evening.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
A frontal system approaches from the west tonight and impacts
the region on Thursday.
VFR tngt. MVFR or lower possible in shwrs and tstms on Thu,
especially wrn arpts. There is a chance for widespread MVFR or
lower in fog and/or stratus Thu ngt at all arpts.
Generally S winds 10kt or less tngt. Winds increase on Thursday
to around 10-15kt with some gusts into the upper teens and
lower 20kt range. Winds decrease blw 10kt aft 00Z Fri.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Confidence in the exact timing and placement of any tstms on
Thu is low.
.OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
Thursday night: MVFR or lower possible with winds aob 10kt.
Friday: Mainly VFR. MVFR or lower at times w/ SHRA and TSRA,
mainly across southern CT.
Saturday-Monday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
Sub small craft conditions are expected through the week.
Southerly flow increases late Wednesday night into Thursday, with
ocean seas getting to around 4 ft and gusts approaching 20 kt.
Otherwise, sub advisory conditions prevail with seas and winds
diminishing for the weekend with a light pressure gradient with high
pressure building across for the weekend.
Rip Currents:
A moderate risk continues today with a weak swell component and
around 10-15 kt S/SW winds.
Winds increase on Thursday out of the S closer to 15-20 kt. This
combined with a building swell of 3-4ft at 5s out of the S/SE will
bring a high risk of rip currents. The risk through much of the day
may end up being moderate for southeast Suffolk, but high is
possible by the late afternoon/evening.
The risk lowers back to moderate on Friday with a lingering 3ft 6s
swell out of the SE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Flood Watch from Thursday afternoon through Thursday evening
for CTZ005-009.
NY...Flood Watch from Thursday afternoon through Thursday evening
for NYZ067>075-176>179.
High Risk for Rip Currents from 6 AM EDT Thursday through Thursday
evening for NYZ075-080-081-178-179.
NJ...Flood Watch from Thursday afternoon through Thursday evening
for NJZ002-004-006-103>108.
MARINE...None.
&&
$$
|
Previous Forecast Discussions may be found at
NWS New York City/Upton, NY (OKX) Office Forecast Discussions.
(Click 'Previous Version' there to view past versions successively.
Some may differ only in time posted.)
Products Courtesy of NOAA-NWS
NWS Information Parsing Script by Ken True at Saratoga Weather - WFO and Products Scripts by SE Lincoln Weather.
Mapping by Curly at Michiana Weather and by Tom at My Mishawaka Weather.












