209
FXUS61 KOKX 311753
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1253 PM EST Tue Dec 31 2024
.SYNOPSIS...
Weak high pressure over the area will slide east this afternoon.
Developing low pressure will then approach from the west 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 series
of disturbances will move across Friday into Saturday. High
pressure will then begin to build from the west on Sunday. Low
pressure could impact the area early next week as it passes mostly
to the south.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Clear skies giving way to some high and mid level clouds moving
in from central/western PA this afternoon ahead of approaching
low pressure. As sfc high pressure moves east, a SE flow will
develop in the afternoon. High temps in the lower 50s will be
well above normal.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
*Period of heavy rain and embedded thunderstorms to ring in the
New year
A strong, negatively-tilted shortwave trough traversing the OH
Valley today will then move into PA/NY tonight. As primary low
pressure moves through the lower Great Lakes region, energy with
the shortwave will induce secondary cyclogenesis over or near
southern NJ this evening, with that low then moving over the CWA
overnight.
A period of moderate to locally heavy rain will precede arrival
of the low and occluded cold front. 12z Fcst soundings have
trended slightly higher with elevated instability MUCAPE above
a sfc- based inversion, as well as enough CAPE in the -10C to
-30C region, to strengthen mention of chance thunder with some
small hail and winds gusts to 40 mph possible for NE NJ, NYC
and western Long Island. Only slight chance thunder fcst for
most areas north/east of there. Timing for rain in the NYC
metro area still looks to be about 01Z-07Z, and an hour or two
later to the north/east.
For New Year`s Day, have continued the forecast of chance PoP
for lingering showers with passage of the parent upper trough,
with drying conditions following for Wed night and Thu.
As the pressure gradient tightens in the wake of the low as it
intensifies and moves along the ern New England coast and then
up into ern Canada, W winds should pick up beginning Wed
afternoon/night especially in the NYC metro area and along the
coast, sustained at 20-25 mph with gusts 30-35 mph. As the
pressure gradient tightens further on Thu winds of this
magnitude or a little higher should occur across the entire CWA,
and if the upward trend in the wind fcst continues, some parts
of the metro area and the coast may need a wind advy for daytime
Thu.
Mild conditions on Wed with highs in the upper 40s/lower 50s
will give way to colder air, with low temps in the lower/mid
30s Wed night, and high temps in the upper 30s/lower 40s on
Thu.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
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 variances 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 will
transition to more trough Friday night. The trough stays
across the region through the weekend and then shifts east
offshore early next week. Any ridging appears brief with more
troughing for next Tuesday.
At the surface, strong low pressure in SE Canada starts the long
term forecast period Thursday night. Then, a disturbance
approaches the region Friday from the west, eventually going
offshore Friday night into early Saturday. High pressure
gradually makes a return, as it slowly builds in from the west
Sunday. However, magnitude of high pressure will not be too
strong.
Low pressure developing south and west moves south of local
region early next week.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
A frontal system approaches from the southwest today with a
developing area of low pressure crossing 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 45-50 kt at 2kft.
Conditions then gradually begin to improve during the day on
Wednesday.
Winds will continue to back to the SE-E at 5-10 kt this
afternoon before increasing to 10-15 kt at the coastal
terminals this evening. Wind direction could 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 with 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 gusts near 20kt.
Gusts up to 25 kt possible.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
As low pressure approaches tonight, expect SE-S flow to increase
to 15-25 kt with frequent gusts to 25-30 kt on the
ocean/bays/ern Sound, with SCA in effect. A few gusts up to 35
kt may be possible on the ocean but of brief duration.
The Gale Watch for the ocean has been upgraded to a Gale Warning
for Wed into Thu. W winds ramp up daytime Wed with gusts up to
35 kt in the afternoon, then solid gale conds expected Wed
night- Thu with sustained winds 25-35 kt and gusts 40-45 kt.
Have also issued a Gale Watch for the ern Sound and Peconic Bay
for Wed night-Thu as model fcsts indicate least marginal gale
force gusts may be possible. The westerly fetch may be favorable
enough for winds to be nearly as strong there as on the ocean,
and cannot rule out gales elsewhere daytime Thu and will mention
this in the HWO.
Gales should linger on most of the waters Thu evening.
Widespread SCA cond expected late Thu night into Fri AM for all
waters. Brief sub-SCA wind gusts Friday afternoon through
Friday evening, before SCA gusts are forecast late Friday night
on the ocean. The SCA gusts are forecast for most of the waters
for Saturday and Saturday night.
SCA levels seas forecast on the ocean and the eastern Sound
Thursday night. Lingering ocean SCA seas forecast Thursday night
into early Friday and then brief sub-SCA seas forecast Friday
afternoon into Friday night. SCA level seas on the ocean
eventually return Saturday into Saturday night.
&&
.HYDROLOGY...
A band of moderate to heavy rain tonight should cause no more
than brief minor nuisance issues. Rainfall rates of 1/4 to 1/2"
likely with heaviest precip, briefly 3/4-1" with any quick
moving convection. Rainfall total of 1/2 to 1", with locally 1
1/2" possible in most 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.
&&
.TIDES/COASTAL FLOODING...
Per latest bias-corrected ETSS and NYHOPS central forecasts,
water levels may touch minor flood thresholds along the south
shore back bays of Nassau/Queens and along parts of NY Harbor
with the Wed AM high tide. Statement issued to address this
possibility. Cannot yet rule out some spots farther east
(Shinnecock/Montauk) getting close to minor thresholds during
this time as well.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 10 PM this evening to 6 AM EST
Wednesday for ANZ331-332-340-345.
Gale Watch from Wednesday evening through Thursday afternoon
for ANZ331-332-340.
Small Craft Advisory until 6 AM EST Wednesday for ANZ350-353-
355.
Gale Warning from 6 AM Wednesday to 6 PM EST Thursday for
ANZ350-353-355.
&&
$$
SYNOPSIS...BG/JM
NEAR TERM...BG/NV
SHORT TERM...BG
LONG TERM...JM
AVIATION...FEB
MARINE...BG/JM
HYDROLOGY...BG/JM
TIDES/COASTAL FLOODING...