discussion on 2024-02-27

000
FXUS61 KOKX 280225
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
925 PM EST Tue Feb 27 2024

.SYNOPSIS...
-- Changed Discussion --A warm front continues moving northward tonight followed by a
strong cold frontal passage Wednesday night. Behind it, high
pressure builds in and remains in control through at least
Friday. An inverted trough or wave of low pressure could then
bring unsettled weather over the weekend into early next week.-- End Changed Discussion --

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --One area of light to moderate, and briefly heavy, rain was
moving to the east and northeast in association with a shortwave
moving through the east side of an upper trough extending
through the central United States. There will be a break, or the
rain will be be very light, late tonight and toward morning
before another round of rain moving into the region with
another shortwave. Updated probabilities through the overnight
to reflect this, using the latest HRRR and NamNest.

As the area remains in the warm sector of a weakening warm
front, a strengthening LLJ will develop over the eastern half
of the area. This LLJ will help to rapidly advect low level
moisture into the area which should allow for the continued
development of showers through the night. There even remains a
possibility of some isolated thunder in the development of any
heavier convective showers into early Wednesday. Lows tonight
will be warm, generally in the upper 40s to low 50s.-- End Changed Discussion --

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
-- Changed Discussion --Deep layer SW flow will dominate Wednesday as the area remains
entirely warm sectored. Periods of rain showers are expected, some
of which may be locally moderate to heavy, especially as the
forcing maximizes ahead of the cold frontal passage Wednesday
afternoon and evening. Highs on Wednesday will be in the middle
50s to low 60s. Overall, around 1 to 1.5 inches of rain is expected
for much of the area, with the highest amounts to the north and east.

One of the biggest impactful aspects of this system is the
potential for strong wind gusts. There will be two separate
opportunities to see advisory level winds in the area over the next
24 to 36 hours. The first is with the mixing down of any winds from
the LLJ ahead of the cold front during much of the day on Wednesday.
There will be a fairly strong inversion in place but with a LLJ
anywhere from 60-80kt near 925 mb, gusts near 40 kt will be
possible. However, it may be the case where the inversion is
strong enough and precipitation is weak enough to not mix down
much of this LLJ energy at all during the day on Wednesday.
Regardless, the potential for strong gusts exists, so a wind
advisory is in effect for the eastern portions of Long Island
and New London County in Southeastern Connecticut to see gusts
in excess of 45 mph in the southerly flow.

The second chance for advisory level wind gusts will be with and
immediately behind the cold frontal passage Wednesday evening and
into the overnight. Strong CAA will allow for a much deeper
mixed layer to bring down strong winds behind the cold front. This
will likely make the wind threat much more widespread than just the
eastern and coastal areas as previously described. As such, a wind
advisory for portions of the Lower Hudson Valley and western
Southern Connecticut are in effect. Winds may gust upwards of 40-50
mph with the cold frontal passage and for several hours afterwards
into the overnight period, gradually diminishing in strength toward
daybreak Thursday.

The cold frontal passage will be strong and very noticeable as
a rapid drop in temperatures is expected Wednesday evening.
Temperatures in the middle 50s Wednesday afternoon are expected
to drop into the 30s over a period of 2-3 hours. This rapid drop
in temperatures will be accompanied by the previously described
strong wind gusts which will make feel apparent temperatures
much colder. Temperatures will continue to drop through
Wednesday night such that lows will be in the middle 20s to
lower 30s. Apparent temperatures will be in the teens.

Precipitation will likely come to an end rather quickly behind
the frontal passage, but flakes mixing in on the back end of the
precipitation can`t be entirely ruled out for much of the area,
though no accumulation is expected. There should be enough of a
period of gusty conditions with little to no precipitation such
that much of the ground should dry out before temperatures drop
below freezing. So the potential for a flash freeze situation
appears limited at this time.-- End Changed Discussion --

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
-- Changed Discussion --High pressure builds in on Thursday with the flow aloft
becoming less cyclonic. However, still breezy with NW gusts as
cold air advection will still be ongoing. Highs only mostly
35-40, and the wind will make it feel about 10 degrees colder.

The center of high pressure then shifts off the the Mid-
Atlantic coast late Thursday night with a return flow being
established on Friday. Warmer, with highs 45-50.

Friday night begins an extended period when there will be a
chance of rain. A wave of low pressure tries to develop to our
south along a trough. The wave potentially meanders somewhere in
the vicinity between the Mid-Atlantic coast and 40N/70W
benchmark through the middle of next week. Stuck closely to NBM
PoPs (which are limited to chance) from Friday night onward due
to the uncertainty. Precip type should be rain. The only
exception would be a low chance that freezing rain occurs over
parts of the far NW fringe of the forecast area if precip were
to occur late Friday night/early Saturday morning. Temperatures
Saturday through Tuesday above normal.-- End Changed Discussion --

.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --A warm front continues moving northward overnight. A strong
cold front approaches Wednesday afternoon and moves through the
terminals Wednesday evening.

VFR to MVFR remains, as VFR conditions continue longer than
forecast. An area of light to moderate rain was moving to the
east and northeast, with the rain tapering off or briefly
ending. MVFR to IFR still expected to become widespread for the
overnight. There will be a period of little to no rain overnight,
however, conditions will remain IFR. There may be a period of
brief improvement to MVFR Wednesday morning, especially away
from the coast. Additional periods of rain move in toward
Wednesday morning, and continue until the cold front passage.

Low level wind shear will be strong, with 2000 ft southerly
winds 50kt to 70kt at the NYC terminals and east, and with the
strongest LLWS at KGON, Wednesday morning into the afternoon.

Otherwise, strong and gusty southerly winds continue tonight
through Wednesday, quickly shifting to the west and remaining
gusty Wednesday evening with the frontal passage.

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

Unscheduled AMD likely for timing of lower flight categories
into Wednesday morning. LLWS may be stronger that forecast with
a low level jet of 65 to 75 kt.

OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...

Wednesday evening: MVFR becoming VFR from the NYC metros
north/west, IFR to the east at the Long Island/CT terminals,
then becoming VFR toward 06Z. S winds G35-40kt along the coast
(with LLWS) and 30-35kt inland, shifting quickly to the west
with a frontal passage.

Late Wednesday night: VFR. West winds G30-35kt.

Thursday: VFR. NW winds 20-25G30-35kt in the morning,
diminishing to 15-20G25kt late in the afternoon.

Friday: VFR. S winds G15-20kt along the coast.

Saturday: Chance of rain. MVFR cond possible.

Sunday: Slight chance of rain. Mainly VFR.

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

.MARINE...
-- Changed Discussion --SCA conditions overtake all waters this evening with wind gusts
upwards of 25 kt. Winds continue to increase tonight over the
ocean with gale force gusts possible as early as 6Z so a Gale
Warning is now in effect for the ocean and Great South Bay
tonight. Ocean seas are also expected to quickly rise to well
above 5 feet by this evening and up to 10 to 12 feet by
Wednesday morning.

Gale gusts likely on most waters except the NY Harbor Wednesday as
flow increases ahead of a cold front, with mainly 35 to 40 kt gusts
on the ocean waters, occasionally up to 45 kt. Seas reach 15 to 17
ft by Wednesday evening on the ocean. Gale warning then expands to
the NY Harbor Wednesday evening as gusts with the frontal passage
are expected to reach or exceed 35 kt.

Gale conditions continue through Thursday morning, then winds and
gusts diminish as cold air advection subsides and the pressure
gradient becomes weaker. SCA conds for Thursday afternoon and
evening, with sub-advisory conds for most of the waters by around
midnight. Seas on the ocean east of Moriches Inlet may linger above
5 ft through most of the night. High pressure will then be centered
well off to our SE on Friday. SW winds pick up during the day with
marginal SCA conds possible on the ocean. Sub-advisory conditions
otherwise anticipated through Saturday, then oceans seas build with
a swell Saturday night into Sunday as a wave of low pressure tries
to take shape off the Mid-Atlantic coast.-- End Changed Discussion --

.HYDROLOGY...
Periods of rain/showers are expected as a frontal system moves
through the region this evening through Wednesday night. Total
expected rainfall is generally between 0.75 and 1.5 inches. Outside
the potential for brief nuisance flooding of urban and poor drainage
locales, no other significant hydrologic impacts are expected.

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Wind Advisory from 6 PM Wednesday to 7 AM EST Thursday for
CTZ005>007-009>011.
Wind Advisory from 7 AM Wednesday to 7 AM EST Thursday for
CTZ008-012.
NY...Wind Advisory from 6 PM Wednesday to 7 AM EST Thursday for
NYZ067>070.
Wind Advisory from 7 AM Wednesday to 7 AM EST Thursday for
NYZ079-081.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EST Wednesday for ANZ331-332-
335-340.
Gale Warning from 6 AM Wednesday to 1 PM EST Thursday for
ANZ331-332-335-340.
Small Craft Advisory until 6 PM EST Wednesday for ANZ338.
Gale Warning from 6 PM Wednesday to 1 PM EST Thursday for
ANZ338.
Gale Warning until 1 PM EST Thursday for ANZ345-350-353-355.

SYNOPSIS...JC/MW
NEAR TERM...JC/MET/MW
SHORT TERM...MW
LONG TERM...JC
AVIATION...MET
MARINE...JC/MW
HYDROLOGY...JC/MW