120
FXUS61 KOKX 042046
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
346 PM EST Wed Dec 4 2024
.SYNOPSIS...
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A strong frontal system will move across the area tonight into
early Thursday. The region then lies between low pressure over
the Maritimes and high pressure over the central states Thursday
night through Friday. The high then slowly moves off the
southeast coast this weekend. A warm front will approach
and pass through on Monday. A slow moving cold front will
then approach from the west from Tuesday into Wednesday.-- End Changed Discussion --
&&
.NEAR TERM /THROUGH THURSDAY/...
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A potent middle level vortmax will dive southeastward from the
Great Lakes region this evening to northeast/Middle Atlantic
coast by Thursday morning. The associated closed upper low will
approach tonight and pass over the area on Thursday. The system
will bring a strong frontal system tonight, with the warm front
lifting over the area first ahead of the main cold front passage
through early Thursday.
The evening should start out dry, but increasing thermal
forcing/warm advection, especially east of the Hudson River
corridor, will aid in the blossoming of precipitation late
evening into the overnight. Precip should develop and become
more widespread after 9pm. Most of the precip will be along and
ahead of the warm front. The precip coverage will likely be more
scattered across NE NJ and the Lower Hudson Valley initially,
but become more widespread early Thursday morning as the potent
shortwave provides more enhanced lift. The precip should then
begin tapering off from west to east after day break as the
strong cold front sweeps through the area. Many of the CAMs are
hinting at a convective line accompanying the front in the
morning, which may bring a brief enhancement before the precip
ends.
Precipitation Types and Amounts...The increasing SW flow will
bring in warmer air which will allow the precip to be mainly
rain across the NYC metro, Long Island and south central and
southeast Connecticut. The interior of the Lower Hudson Valley,
southwest Connecticut, and NE New Jersey will be mostly snow.
There may be some wet snow flakes mixed in at the onset near the
Hudson River Corridor/NYC metro and then again as the potential
convective line moves through with the cold front early in the
morning. There has not been much change with regards to snowfall
accumulation with less than an inch across interior Lower
Hudson Valley to around 1-2 inches across interior Southwest
Connecticut (northern Fairfield and northern New Haven counties).
Some higher elevations in northern Fairfield and northern New
Haven could see locally higher around 3 inches. Will mention
potential for slick travel in the HWO for these zones.
Otherwise, little to no snow accumulation is expected outside
of the aforementioned areas. Liquid equivalents range from
around a tenth west to one half to three quarters eastern Long
Island and southeast Connecticut.
Winds...No changes made to the wind advisory headline Thursday
into Thursday evening. S-SW flow strengthens tonight with
potential of gusts 25 to 35 mph, especially along the coast.
Winds will pick up quickly with the cold front passage Thursday
morning. A steep pressure gradient, a well mixed boundary layer,
and strong cold advection will increase westerly winds to 20-30
mph with gusts 45 to 50 mph. The strongest gusts are most
likely to occur in the afternoon and early evening.
There will be improving sky conditions behind the front, but
varying levels of stratocu are likely in the cold advection
regime. There may also be some flurries or even a few snow
showers in the afternoon. Daytime highs will be in the upper
30s inland to the lower 40s near the coast. Some areas may see
their max temp for the day occur ahead of the front with
temperatures remaining colder for the rest of the day. The
strong winds will make it feel colder, with wind chills only
in the 20s.-- End Changed Discussion --
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
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Strong winds continue Thursday evening as the region will lie
between deep low pressure over the Maritimes and high pressure
over the central states. The closed upper low and trough axis
push offshore, but there will be another dry front/surface
trough that passes late Thursday night and early Friday morning.
This will reinforce the cold air and bring in even drier dew
points. The low level winds will weaken however and we should be
below advisory levels by late Thursday evening. The end time of
the Advisory looks good (10pm). Wind gusts 25-35 mph, strongest
near the coast, continue with temperatures falling into the 20s
for much. Wind chills look to be in the teens by early Friday
morning, with potential for a few spots around 10 inland. Any
lingering flurries Thursday evening should end after sundown.
Breezy and cold conditions continue on Friday. NW gusts look to
reach 25-30 mph with temperatures only in the low to middle 30s.
There should be some stratocu for at least partly cloudy skies, but
no precipitation is expected at this time.-- End Changed Discussion --
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
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The large upper trough that has been responsible for recent cold
wx will finally slide east this weekend, replaced by broad
ridging quickly propagating over from the Western states Sunday
and Monday. As this ridging slides east, deep layer SW flow
ahead of an amplifying trough over the nation`s mid section will
then take hold going into mid next week. Temps on Sat 5-8
degrees below avg on Sat will quickly moderate to slightly above
avg on Sunday as a warm front passes to the north and sfc high
pressure moves to the SE coast. As another warm front moves
directly toward the area and on Mon and lifts through by
evening, temps should modify further above normal on Mon, with
highs in the upper 40s/lower 50s, and a little warmer than that
for Mon-Tue with highs reaching the lower/mid 50s.
With the approach of the warm front on Mon, expect rain to become
likely through the day. If precip arrives early enough Mon morning
there is a slight chance of precip beginning briefly as -FZRA in the
valleys of Orange County.
With the area in the warm sector ahead of a slow moving cold front
aligned with the flow aloft going into mid week, capped any likely
or greater NBM PoP to 50 percent through the rest of the fcst
period. Timing of the front is uncertain, with the faster ECMWF
bringing it through before daybreak Wed, and the slower GFS
lagging until Wed afternoon out east.
Chance PoP continues into Wed and Wed night as fcst uncertainty
increases further regarding timing and track of a low coming out of
the Gulf States. Faster GFS starts bringing significant precip as
early as Wed night-Thu, while the ECMWF holds off until beyond
the fcst period.-- End Changed Discussion --
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
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Deepening low pressure centered north of the Great Lakes tracks
east through Thursday afternoon as a warm front approaches and
possibly passes through the region this evening. A cold front
then approaches late tonight and passes through Thursday
morning.
VFR until around 03Z this evening, then increasing chance of
MVFR with rain at the coast, possible a rain/snow mix at the
start with IFR. Snow at KSWF with MVFR to IFR, with total
snowfall of 1/2 to 1 inch. Precipitation ends Thursday morning
with passage of a cold front, and conditions improve to VFR.
Winds SSW 10-15kt, with occasional gusts mainly along the coast.
Winds become more SW and increase further this evening with gusts 25-
30kt. Thursday morning, 13Z to 16Z, winds become west around 25kt
with gusts 35-40kt.
...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty...
Start time of precipitation may be an hour or two earlier, low
to moderate confidence.
Brief IFR ceilings possible this evening with a rain/snow mix, low
confidence on occurrence.
Peak westerly gusts Thursday afternoon may be as high as 43kt,
moderate confidence.
OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
Thursday afternoon: VFR, slight chance of flurries with brief MVFR
possible. W winds 20-25kt, gusts 35-40kt, occasional gusts 40 to
45kt possible.
Thursday night: VFR. W winds G35-40kt early, gradually diminishing
to G25kt late at night.
Friday: VFR. NW winds G25-30kt.
Saturday - Sunday: VFR.
Monday: MVFR with a chance of rain showers, IFR in the afternoon
with rain showers.
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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Increasing SW winds are expected tonight ahead of a strong
frontal system. Gales should develop on the ocean towards
midnight and then become widespread into early Thursday morning.
Gales on the non ocean waters may be marginal initially, but
will become widespread and frequent Thursday morning behind the
cold front passage. Gales will then continue through Thursday
evening before slowly diminishing on the Sound, Harbor and Bays
towards early Friday morning. Rough conditions are likely due to
elevated seas with 10-14 ft waves on the ocean and 4 to 7 ft
waves on the Sound Thursday.
Low water levels are possible near shore during the daytime low
tide on Thursday. Water levels may fall to around -2 feet MLLW.
Rough conditions will continue on Friday with SCA winds on all
waters. Waves will subside through the day, but should still
range from 4 to 7 ft by Friday afternoon.
SCA cond on all waters except perhaps NY Harbor Fri evening, with
gusts 25-30 kt and ocean seas 5-6 ft E of Fire Island Inlet, will
gradually abate late Fri night into Sat, with 25-kt gusts confined
to the ocean and ern bays late Fri night, and to the ern ocean
waters daytime Sat as seas fall to 4 ft.
After a lull Sat night, SCA cond should return to the ern ocean
waters and the ern Sound/bays by daytime Sunday and continuing into
Mon as WSW-SW flow after a warm frontal passage increases, with
gusts over 25 kt and seas 5-7 ft. There may be a brief lull in these
conditions late Sunday night into Mon morning.-- End Changed Discussion --
&&
.HYDROLOGY...
There are no hydrologic concerns through early next week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Wind Advisory from 6 AM to 10 PM EST Thursday for CTZ005>012.
NY...Wind Advisory from 6 AM to 10 PM EST Thursday for NYZ067>075-
078>081-176>179.
NJ...Wind Advisory from 6 AM to 10 PM EST Thursday for NJZ002-004-
006-103>108.
MARINE...Gale Warning until 1 AM EST Friday for ANZ331-335-338-340-345.
Gale Warning until 6 AM EST Friday for ANZ332-350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...BG/DS
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...BG
AVIATION...MET
MARINE...BG/DS
HYDROLOGY...BG/DS