398
FXUS61 KOKX 132141
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
441 PM EST Thu Feb 13 2025
.SYNOPSIS...
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Low pressure will track into the Canadian Maritimes tonight,
allowing high pressure to gradually build in from the west on
Friday. High pressure Saturday morning quickly gives way to a
storm system approaching from the mid section of the country.
The associated warm front approaches Saturday into Saturday
night. Deepening low pressure will then track to the north and
west of the area Sunday, with a secondary coastal low developing
nearby. The latter of which will drag a cold front through the
area Sunday afternoon into early evening. High pressure then
slowly builds back in early next week. Low pressure may impact
the area mid week.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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Low pres was analyzed in the Gulf of Maine at 20Z. In the wake
of the low, winds have come around to the W across PA, NJ, NYC
and LI, and this will spread newd into the rest of the cwa this
eve. Across wrn PA, there were some gusts to around 40kt, and
based on the modeled wind profiles, this surge should reach the
local area tngt. The main limiting factor for gust magnitude is
the overnight timing and weak llvl lapse rates. As a result, the
fcst keeps winds just blw advy lvls, but the numbers have been
increased fairly substantially abv the model guidance -
particularly the NBM. The grids indicate an initial surge in
the 00-04Z range, then settling down slightly into the mrng.
This initial surge is where we could have some isold advy lvl
gusts.
Otherwise, the fog and dz will exit due to the wly flow, and skies
will clear this eve with dry air and subsidence. Upstream stratus
might hold together to produce some sct 3-4kft clouds overnight, but
downsloping should limit coverage.
With a well mixed bl, the NBM temps seems reasonable with local
adjustments.-- End Changed Discussion --
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
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Windy and dry or Fri with deep subsidence and a dry airmass.
Increasing mid and high clouds in the aftn. With this setup,
increased winds abv the blended guidance. H85 in the NAM roughly
45kt, slightly less in the GFS. As a result, gusts to around 40 mph
seems reasonable attm.
Winds do decrease significantly Fri eve and ngt as a 1030s high
ridges across the region. Fairly thick mid and high clouds however
from the next sys approaching, so this should limit radiational
cooling potential.
Fro Fri and Fri ngt went close to the NBM for temps which produces
highs in the 30s and lows in the teens and 20s.-- End Changed Discussion --
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
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Another amplified southern branch storm system will impact the
area Saturday afternoon into Sunday. Low pressure over the Mid
Mississippi Valley will be preceded by strong thermal forcing
that moves into the area Saturday ahead of the associated warm
front. There has clearly been a colder trend in the guidance
over the last couple of days with probabilities increasing both
with the NBM and long range ensemble forecast system (EPS,
GEFS, and GEPS) for an advisory level snowfall event for CT,
the Lower Hudson Valley, and interior NE NJ. Even the 12Z GFS
and NAM show this potential across NYC and LI before a changeover
to all rain. However, confidence is lower for coastal locations
due to retreating and weakening high pressure and an onshore
southerly component. Typically, these ingredients don`t fair
well for a significant winter precipitation event. However,
these type of systems of late with decent thermal forcing have
provided accumulating snow before the elevated warm nose comes
in aloft. There is no doubt the precipitation will change over
to rain with a deep-layered strengthening W/SW flow ahead of the
amplifying southern branch upper trough. How quickly that
happens will be key to the amount of snow. In addition, there
now looks to the potential for significant icing across the
interior once the precipitation changes over rain. The surface
warm front is poised to stay south of the area through Saturday
night and arrives along the coast Sunday morning. However, it
now looks like the approaching upper forcing will result in the
quicker development of a secondary low along the coast Sunday in
close proximity to the area. While this will not inhibit the
warm air from arriving aloft, it will likely slow down the
erosion of the low-level cold air across some of the interior,
especially across northern portions of the Lower Hudson Valley
and northern portions of Fairfield and New Haven counties in SW
CT. These locations have the potential for a tenth of an inch or
more of ice accretion. The combination of snow and ice could
also necessitate a Winter Storm Watch within the next 24h for
some of these locations, and at the very least Winter Weather
Advisories.
As for temperatures, overnight lows Saturday morning will be in
the teens inland to the lower/mid 20s along the coast. Temperatures
will then be slow to rise and may not go above freezing until
late afternoon/early evening along the coast, and as late as
Sunday morning for the far interior. Temperatures on Sunday
then rise up into the upper 30s inland and upper 40s along the
coast.
Following a cold frontal passage Sunday afternoon and evening,
a much colder airmass arrives for next week. In fact, the NBM
has continued to trend down the last 24h and will continue to
go slightly colder at this time. A piece of arctic air associated
with a polar vortex drops across the Great Lakes Sunday night
into Monday. This will be accompanied by a gusty WNW flow Sunday
night into Tuesday. Highs will top out generally in the 20s with
lows in the single digits to teens beginning Tuesday morning,
Winds chill values will be as low as the single digits at night
and in the teens during the daytime.
Cold high pressure builds in for Wednesday with some uncertainty
with the southern branch storm track. Long term models differ
in the timing and track of low pressure passing to the south
late Wednesday into Thursday. There are low chances for snow
at this time.-- End Changed Discussion --
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
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A cold front passes across the terminals this afternoon. High
pressure then builds in tonight into Friday.
Conditions will continue to improve to VFR through 22z with VFR then
prevailing through Friday.
Winds will also continue shifting to the W late this afternoon.
Winds will then become WNW-NW this evening and increase to 15-20kt
with gusts 25-30 kt. Some peak gusts around 35 kt possible this
evening. Gusts will weaken slightly early Friday morning before
increasing again to 25-30 kt after 14z.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Peak gusts around 35 kt possible at times this evening.
.OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...
Friday Afternoon-Night: VFR. NW wind gusts 25-30 kt in the
afternoon.
Saturday-Saturday Night: VFR early, the IFR in snow in the
afternoon. The snow should transition to rain along the coast in
evening, and inland at night. A wintry mix may remain inland through
the night.
Sunday: IFR or lower. Rain with a chance of freezing rain inland in
the morning. LLWS possible. S Gusts 20-25 kt.
Monday: VFR with WNW wind gusts 30-35 kt.
Tuesday: VFR with WNW wind gusts 20-25 kt.
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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Fog decreases and winds increase this eve as low pres pulls away.
The dense fog advy has been canceled, and the gale wrng has been
expanded to all waters. Gales are expected thru Fri, with winds and
seas decreasing rapidly late Fri and Fri ngt.
High pressure on Saturday morning gives way to another storm
system Saturday afternoon into Sunday. SCA conditions are
forecast to redevelop on the ocean waters late Saturday night
and across all waters Sunday in a strengthening southerly flow
ahead of an approaching cold front and deepening low pressure
passing to the northwest. However, behind a strong cold frontal
passage late Sunday afternoon into evening, a westerly gale
will be possible across all waters Sunday night into Monday.-- End Changed Discussion --
&&
.HYDROLOGY...
There are no hydrologic concerns through the period.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None.
NY...None.
NJ...None.
MARINE...Gale Warning until 4 PM EST Friday for ANZ331-332-335-338-340-
345-350-353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JMC/DW
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...DW
AVIATION...DS
MARINE...JMC/DW
HYDROLOGY...JMC/DW