405
FXUS61 KOKX 312231
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
531 PM EST Tue Dec 31 2024

.SYNOPSIS...
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Developing low pressure will approach from the southwest this
evening, pass over the area late tonight, then move along the
eastern New England coast Wednesday into Wednesday evening and
into eastern Canada late Wednesday night into Thursday. A cold
front moves through Friday night. Weak high pressure builds in
for the weekend. An area of low pressure passes to the south
early next week.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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*Two to four hour period of locally heavy rain and embedded
 thunderstorms to ring in the New year

A strong, negatively-tilted shortwave trough over the Ohio Valley
this afternoon will pivot into PA/NY tonight. At the surface,
primary low pressure moves ne from Ohio this afternoon through
the eastern Great Lakes region this evening. Shortwave and ulj
energy will induced secondary cyclogenesis along its associated
warm front over the DelMarVa this evening, and the tracking
over or just south of the local Tri- State tonight.

Expect shower activity to increase from SW/NE between 6pm and 8pm
this evening. A 2 to 4 hr period of moderate to locally heavy
rain with embedded thunderstorm activity likely between 8pm and
2am immediately ahead of and southeast of the developing low.
Rainfall rates of generally 1/4" to 1/2" for a 2 to 4 hr period,
with brief peak rates of 3/4" to 1" possible with any training
convection. Minor urban and poor drainage flooding possible.

12z Fcst soundings have trended slightly higher with elevated
instability (MUCAPE) above a sfc-based inversion, as well as
CAPE in the -10C to -30C region, to strengthen potential for
isolated thunderstorms across NE NJ, NYC and western Long
Island. Only slight chance thunder fcst for most areas
north/east of there. Small hail and winds gusts to 40 mph
possible with any isolated stronger thunderstorms.

Severe tstms are not expected based on consensus low pressure
track and with modest low-level inversion, but a further NW jog
of low pressure would introduce less than a 5% risk of damaging
winds gusts and less than a 2% tor risk (within 25 miles of a
point) into southern portions of NYC/NJ metro and LI. Very low
prob of this occurring.

Timing for rain in the NYC metro area still looks to be about 00Z-
07Z, and an hour or two later to the north/east. Peak timing of
thunder from 02z to 06z in the NYC metro area, and an hour or
two later to the north/east

In Addison, nose of 35 to 40 kt LLJ slides across coastal areas
this evening, with a few hours of peak SE winds of 15 to 20 mph
gusts 25 to 30 mph ahead of low/occluded front.

Rain tapers to isolated shower activity from west to east
between 5z and 9z in wake of occluded front/low pressure, but
still under deep cyclonic flow. Generally light westerly flow
in wake of front overnight and weak CAA, with temps remaining
well above seasonable in the 40s.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
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Deep troughing continues across the northeast US thru the period,
with lead shortwave sliding east Wed AM, and trailing shortwave
approaching Wed aft and crossing Wed eve. At the surface,
coastal low pressure departs up the New England coast on Wed,
with secondary cold front crossing the region Wed aft.

The pressure gradient tightens in the wake of the deepening and
departing low Wed AM. W winds should pick up beginning Wed AM,
with strongest winds in wake of cold front/trough Wed aft/eve
with 20 to 30 gusts 45 to 55 mph. Gradient remains strong
overnight, with winds 45-50 kt at top of mixed layer, but with
lapse rates weakening a bit overnight, peak wind gusts will
likely remain capped at 45 to 50 mph into Thu AM. Pressure
gradient appears to remain tight into Thu aft as low pressure
deepens over northern Maine/new Brunswick, with winds at top of
mixed layer 45-50 kt in a steeper mixing profile. This should
support resurgence of westerly 45-55 mph wind gust threat into
the afternoon. Wind advisory to address hazard for Wed aft into
Thu eve.

Considerable cloud cover in cyclonic flow, with scattered rain
shower likely Wed aft/eve with shortwave/cold frontal passage. With
cold advection behind front, a few snow showers possible at tail
end across interior, particularly higher elevations.

Mild conditions on Wed with nearly stationary highs in the upper
40s/lower 50s giving way to cold advection late Wed aft into
into Thu. Low temps in the lower/mid 30s Wed night, and high
temps in the upper 30s/lower 40s on Thu. Windchills in the 20s
Wed Night thru Thu.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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Key points include cold/blustery/mainly dry conditions until
potentially early next week, with chances of snow. Uncertainty is
high for early next week with resulting wide ranges of snowfall
forecasts. Temperatures forecast to become more below normal through
the weekend. The gusty winds will make it feel about ten degrees
colder than the actual temperatures regarding the forecast high
temperatures.

Mid level quasi-zonal flow Thursday night into Friday. A longwave
trough moves over the Eastern Seaboard late Friday, with the trough
axis moving offshore late Friday night. A surface cold front is
expected to move through Friday night. However, it looks to do so
mainly dry. Thereafter, weak high pressure builds in at the surface
as the trough departs for the remainder of the weekend, keeping the
area dry. A southern stream trough approaches Sunday night with a
weak area of low pressure from the central or south central US
(given some uncertainty), and passes south of the area Monday night
into Tuesday. Current model consensus it to take this low south of
the area late Monday into Monday night. The area could see some snow
on the northern fringes of this system, but there is still a great
deal of uncertainty this far out, and stuck pretty close to the NBM.

Temperatures should average below normal through the period.
-- End Changed Discussion --

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
A developing area of low pressure crosses over the terminals tonight
before exiting to the northeast during the day on Wednesday.

VFR conditions will prevail through 00Z, then quickly deteriorate to
MVFR/IFR after 02Z in rain. A few thunderstorms are possible as
well, generally between 02-05Z. A period of LLWS is also expected
late this evening with SE winds near 40-45 kt at 2kft. Conditions
then gradually begin to improve during the day on Wednesday.

SE winds at 5-10 kt will continue to back to the E this evening
while increasing to 10-15 kt at coastal terminals. Wind direction
will vary significantly between 06-12Z as low pressure passes
overhead. Winds then return out of the W Wednesday morning and
increase in speed through the day, with gusts 25 kt or greater by
18Z at most terminals.


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

Amendments likely tonight with the onset of rain and lowering
cigs/vsbys. Wind direction will become highly variable overnight as
low pressure moves across the area.

OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...

Wednesday afternoon: Improving to VFR. Chance of -SHRA at KSWF in
the afternoon. Increasing W winds G25-35kt, occasionally up to 40
kt, by afternoon.

Thursday: VFR. W winds G25-35kt with occasional gusts up to 40 kt.
Gusts decrease Thursday night.

Friday through Sunday: Mainly VFR. W winds G20-25kt.

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

&&

.MARINE...
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As low pressure approaches tonight, expect SE-S gusts to 25-30 kt
developing on the ocean this evening and then translating eastward
across southern bays and eastern LI Sound. A few gusts up to 35 kt
may be possible on the eastern ocean waters, but appears too
inverted for any more than brief and infrequent.

Winds should subside below SCA briefly on all waters late tonight in
wake of developing low pressure. Westerly winds then quickly
increasing thru SCA to Gale Wed AM into early afternoon for the
ocean waters, and then all waters Wed aft. Sustained W winds
25-35 kt and gusts 40-45 kt expected to continue into Thu eve,
before gradually diminishing to SCA Thu night. Gales should
linger on most of the waters Thu evening.

Widespread SCA cond expected late Thursday night through much of
Friday for all waters. Winds diminish Friday night, but remain
above 25 kt on the ocean, while non-ocean waters fall below
25 kt. An extended period of SCA for the weekend as gusts are
forecast to be 25 to 30 kt for most of the waters and seas on
the ocean build to 5 to 7 ft through Saturday night, slowly
diminishing on Sunday
-- End Changed Discussion --

&&

.HYDROLOGY...
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Rainfall rates of 1/4 to 1/2" likely with heaviest precip, briefly
3/4-1" with any heavier convection this evening. Basin-wide
rainfall totals of 1/2 to 3/4", with locally 1 1/2" possible
if/where there is more persistent heavy rain shower/tstm
banding. Most of this falls in a 3 to 4 hr time period, which
may cause some minor urban and poor drainage flood issues.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
Per bias corrected ETSS/ESTOFS and NYHOPS central forecast blend,
water levels may touch minor flood thresholds along the south shore
bays of LI (including eastern Great South Bay, Moriches Bay,
and Shinnecock Bay), Jamaica Bay and along the most vulnerable
portions along NY Harbor with the Wed AM high tide. Statement
issued to address this.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Wind Advisory from 3 PM Wednesday to 10 PM EST Thursday for
     CTZ005>012.
NY...Wind Advisory from 3 PM Wednesday to 10 PM EST Thursday for
     NYZ067>075-078>081-176>179.
NJ...Wind Advisory from 3 PM Wednesday to 10 PM EST Thursday for
     NJZ002-004-006-103>108.
MARINE...Small Craft Advisory until 6 AM EST Wednesday for ANZ331-332-
     340-345.
     Gale Warning from 1 PM Wednesday to 10 PM EST Thursday for
     ANZ331-332-335-338-340-345.
     Small Craft Advisory until 6 AM EST Wednesday for ANZ350-353-
     355.
     Gale Warning from 6 AM Wednesday to 1 AM EST Friday for ANZ350-
     353-355.
-- End Changed Discussion --

&&

$$

SYNOPSIS...JP/NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...JP
AVIATION...FEB
MARINE...JP/NV
HYDROLOGY...JP/NV
TIDES/COASTAL FLOODING...