000
FXUS61 KOKX 251440
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
940 AM EST Sat Nov 25 2023
.SYNOPSIS...
High pressure builds in today and shifts offshore tonight. Low
pressure develops along the Middle Atlantic coast late Sunday and
impacts the region Sunday night into early Monday. High pressure
then gradually builds back into the region through Tuesday night,
then weakens Wednesday as low pressure passes to the north
Wednesday through Wednesday night. High pressure returns for late
in the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Forecast remains on track this morning. High pressure continues
to settle overhead this morning and will remain in control
through the day. A weak gradient has persisted a bit longer
across eastern Long Island and southeastern Connecticut, but
should diminish further the next few hours with the high
settling overhead.
High temperatures will only rise to the upper 30s to low 40s
today, more typical of the end of December and early January.
Model soundings show around -7C at 925 mb at 12z this morning.
This is less than the 10% moving average for the 11/25 12z OKX
soundings per SPC Sounding Climatology Page.
The high shifts offshore tonight, with a only a very light return
flow setting up. Mid and high level clouds increase the second half
of the night, so low temperature forecast is a bit tricky.
Temperatures likely drop fairly quick the first half of the night
and then level off if not rise a degree or two the second half of
the night. Lows will likely end up being close to Friday night.-- End Changed Discussion --
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
High pressure shifts farther offshore on Sunday as heights gradually
fall aloft in response to an amplifying upper trough approaching. An
associated surface low will be deepening well north of us in eastern
Canada as it tracks east. As the upper trough approaches it will
interact with an inverted trough off the southeast coast and
organize low pressure. This low will approach from the south and
deepen as it passes right over the area.
In terms of weather, the coastal low will bring a quick shot of rain
late Sunday evening through Monday morning. Although model differences
exist in exact track, there is decent agreement on a widespread
0.75 to 1 inch of rainfall, with periods of moderate rainfall
rates. See Hydrology section below.
Strong cold air advection sets up as the low pulls away and high
pressure builds in from the south and west. There is lower
confidence in the wind forecast Sunday night as the low passes
overhead due to the model spread in track, but confidence is
high in gusty winds as the low pulls away on Monday and Monday
night. Blended in some of the NBM 90th percentile wind gusts
during this time period. Expect sustained westerly winds 15 to
20 mph with gusts 25 to 30 mph.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A strong and gusty westerly flow continues across the region Tuesday
as an upper trough moves through the region and surface low pressure
continues to deepen across eastern Canada. Deep mixing during the
day, up to 700mb by late day, will allow for 30-35kt winds aloft to
mix to the surface. With the NBM indicating the possibility of around
30kt gusts with the max gusts to around 35 kt, especially along the
coast, have used the 90th percentile for gusts into Tuesday evening.
A deep closed upper low remains across eastern Canada and into the
eastern states into late in the week. While surface high pressure
briefly builds into the area late Tuesday and Tuesday night, another
shortwave rotating through the upper trough will allow a low to pass
to the north Wednesday and Wednesday night.
Zonal flow develop in the wake of the Wednesday shortwave, with
surface high pressure building into the area and moving off shore
late Friday. There is a lot of uncertainty with a southern stream
shortwave that moves into the weak zonal flow, with indications that
the wave remains rather flat and weak Friday night into next
Saturday.
Temperatures Tuesday through Thursday night will be as much as 10
degrees below normal, with some moderation toward normal levels
Friday as return flow sets up as high pressure moves offshore. The
NBM looks reasonable for temperatures and was used through the
extended period.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
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High pressure builds in from the west and slides overhead into
this evening, moving offshore late tonight.
VFR.
Winds remain light, less than 10 kt, through the forecast. As
the high builds overhead, direction backs from the N to the
W, then S/SW late in the day, before becoming light and
variable at all the terminals this evening. The timing of the
wind direction changes could fluctuate a few hours.
Some high cirrus remains aloft through the forecast, though
cigs lower to between 3 kft and 5 kft late Sun AM ahead of the
next incoming storm system.
...NY Metro(KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled amendments expected.
Timing of wind direction changes may be off by a few hours.
OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY...
Sun: VFR. There is a chance of MVFR ceilings along the coast by
afternoon. Only a slight chance of rain late in the day along the
coast. Sunday night rain with MVFR to IFR. SE wind 10-15kt becoming
SW and diminishing toward morning.
Mon: VFR at the NYC metro terminals and northwest. A chance of rain
early east with MVFR to IFR, then becoming VFR. WNW wind 15-20kt,
G25-30kt.
Tue: VFR. W wind 15-20kt, G25-35kt.
Wed: VFR. W wind 10-15kt, G20kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
-- Changed Discussion --
As high pressure builds in, the pressure gradient will continue
to decrease and lead to decreasing winds. Conditions remain
below SCA criteria through at least Sunday. Low pressure
approaches from the south Sunday and passes overhead Sunday
night as it deepens. Although there could be 25 kt gusts Sunday
night, it looks like the strongest winds from this system occur
when the low pulls away in strong cold air advection. Wind gusts
likely reach 30 kt on all waters, with the potential for 35 kt
on the ocean waters. Winds lower a few kt for Monday night.
These winds will result in 6 to 8 ft waves on the ocean waters
and 5 to 6 ft waves across the central and eastern Sound.
Small craft advisory conditions will be on-going across the forecast
waters Tuesday morning as gusty westerly winds continues with deep
low pressure across eastern Canada and high pressure building to the
west. Several hours of gale force gusts are possible on the ocean
waters Tuesday afternoon. SCA conditions continue into Tuesday
evening, however, conditions will be improving slowly from the west
as high pressure builds to the west, and by Wednesday morning SCA
conditions will remain on the ocean waters, mainly east of Fire
Island Inlet. And, by midday Wednesday the eastern ocean waters will
be marginally below advisory levels. Marginal SCA conditions then
remain on the ocean waters Wednesday night as the pressure gradient
remains rather strong as a low passes to the north.-- End Changed Discussion --
&&
.HYDROLOGY...
There are no hydrologic concerns through Sunday evening.
A widespread three quarters to one inch of rainfall is likely Sunday
night into Monday morning with only minor nuisance and poor
drainage flooding possible.
There are no hydrologic concerns Monday afternoon through
Friday with dry weather expected.
&&
.TIDES/COASTAL FLOODING...
-- Changed Discussion --
Astronomical tides will be increasing into early next week due
to a full moon early Monday morning. Water levels should fall
just short of minor flooding benchmarks with the Sunday morning
high tide for the most vulnerable locations along the south
shore back bays of Southern Nassau. Minor coastal flooding looks
more likely for the south shore back bays of Nassau and Queens,
Western Long Island Sound across coastal Westchester and
coastal Fairfield with the Monday morning high tide. A quickly
developing low pressure may help bring enough of a surge (only
around 0.50-0.75 ft needed) to reach minor benchmarks. It looks
more marginal across the Lower NY Harbor at the present time.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...None.-- End Changed Discussion --
&&
$$
SYNOPSIS...MET/JT
NEAR TERM...JT/DS
SHORT TERM...JT
LONG TERM...MET
AVIATION...DR/MET
MARINE...MET/JT
HYDROLOGY...MET/JT
TIDES/COASTAL FLOODING...JT/DS