629
FXUS61 KOKX 311012
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
512 AM EST Tue Dec 31 2024
.SYNOPSIS...
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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.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Clear skies attm will slowly give way to some high and mid
level clouds moving in from central/western PA mainly 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.-- End Changed Discussion --
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
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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. Fcst soundings also show enough
MUCAPE above a sfc-based inversion, as well as enough CAPE in
the -10C to -30C region, to warrant mention of chance thunder
with some small hail 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
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.-- End Changed Discussion --
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
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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 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.-- End Changed Discussion --
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
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Weak high pressure builds in from the southwest very early and
then quickly gives way to a frontal system approaching from
the southwest today. A secondary low develops just southwest of
the area early this evening and then moves quickly across the
area at night.
VFR is expected to prevail through 00Z Wednesday. Conditions
then quickly deteriorate lowering to MVFR/IFR with about a 3-4
hour period of moderate to heavy rain along with chances of
some thunderstorms. Small hail and more gusty winds than
forecast are a possibility for some thunderstorms. There is
forecast to be LLWS with SE winds near 45-50 kt at 2kft for mid
to late evening.
SW-W winds early will generally be around 10 kt or less. Winds
will then back around to the SE/E at 5-10kt by afternoon,
increasing 10- 15kt with gusts up to near 20kt at the coastal
terminals in the evening. Wind will then vary significantly in
direction late at night as low pressure lifts across the area.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
Timing of wind shift to the E/SE in the afternoon may vary by
1-2 hours.
Amendments likely tonight with the onset of rain and lowering
cigs/vsbys. Wind shifts will also become highly variable as
low pressure moves across the area.
OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY...
Late Tonight: IFR/MVFR likely in rain, improving to mainly MVFR
toward daybreak.
Wednesday: MVFR or lower with chance of -RA in the morning,
improving to VFR in the afternoon. Chance of -SHRA at KSWF in
the afternoon. W winds G25-30kt. Occasional gusts up to 35 kt.
Thursday: VFR and very windy. W winds G25-35kt. Occasional gusts
up to 40 kt. Gusts decrease at night to closer to 20 kt.
Friday and Saturday: 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...
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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.-- End Changed Discussion --
&&
.HYDROLOGY...
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A band of moderate to heavy rain tonight should cause no more
than brief minor nuisance issues.-- End Changed Discussion --
&&
.TIDES/COASTAL FLOODING...
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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.-- End Changed Discussion --
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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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.-- End Changed Discussion --
&&
$$
SYNOPSIS...BG/JM
NEAR TERM...BG
SHORT TERM...BG
LONG TERM...JM
AVIATION...JM/DW
MARINE...BG/JM
HYDROLOGY...BG
TIDES/COASTAL FLOODING...BG