836
FXUS61 KOKX 082112
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
412 PM EST Sat Feb 8 2025
.SYNOPSIS...
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Low pressure system approaches from the west for tonight with a
secondary low developing late tonight south of Long Island. The
second low eventually tracks northeast away from the region Sunday
into Sunday night towards the Canadian Maritimes. Meanwhile, high
pressure will return Sunday into Sunday night across the area. This
high pressure area will continue to build in through Monday
night. A series of lows will impact the area Tuesday through
Thursday. High pressure returns to end the week and start the
weekend.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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Winter storm warnings and winter weather advisory go into effect
this evening and remain the same as before with their areal
content. The snow amounts were adjusted slightly higher to
reflect an overall upward trend in QPF. Lower Hudson Valley,
interior NE NJ with their higher elevations and much of Southern
CT in a general 6 to 8 inch range for forecast snow. Advisories
closer to the coast have a general 3 to 5 inch range. The snow
amounts generally closer to 5 with some localized 6 inch amounts
along the northern half of NYC and Long Island.
Also, emphasized freezing rain and freezing drizzle overnight
into Sunday morning. Little more ice expected across the
interior where freezing drizzle will linger into Sunday morning.
Several hundredths of an inch of ice to near a tenth of an inch
across parts of the interior while closer to the coast, a
hundredth or two of inch, just a glaze of ice expected.
Parent low approaches from the west this evening and then a
secondary low develops south of Long Island late tonight. The
secondary low takes a track through the 40N/70W benchmark going into
early Sunday morning.
Strong zonal upper level jet will allow for the surface low to move
through quickly tonight. The low pressure system`s low level jet
moves across late this evening into overnight. The rapid increase in
low level frontogenesis and warm air advection aloft will allow for
efficient precipitation production across the region this evening.
Moderate to heavy snow is expected until late this evening.
Late this evening and going into overnight, the highest
frontogenesis shifts northeast of the region. However, gradual
mid level positive vorticity advection moves in. Low level warm
nose between 850mb and 700mb moves in with temperatures a few
degrees above freezing near that level. This will allow for a
wintry mix to develop from SW to NE across the region. Expecting
mostly sleet to mix in with the snow and this will cut down on
the total snowfall accumulations. Across the interior, they will
have more time with pure snow, allowing for more snowfall
totals especially across much of Southern CT. Eventually, enough
warming aloft in that 850-700mb layer occurs to make for
freezing rain for portions of the area. This low level warming
above the surface comes in for the southern half of the forecast
region late this evening. Overnight, this area of low level
warmth above the surface moves northeast farther into the
interior.
The associated dry slot with the low pressure system eventually
moves across overnight, drying out mid to upper levels towards
Sunday morning and thereby there is a lack of ice nuclei. This
will make for increasing likelihood of freezing drizzle.
This freezing drizzle will extend icy surface conditions for any
untreated surfaces into Sunday morning. Possible lingering snow
across the interior especially Southern CT for Sunday morning
as well. This will be dependent on how well the low offshore
matures and develops precipitation back to the northwest with
deformation.
Temperatures expected to just slightly decrease this evening and
remain nearly steady overnight, mid 20s to near 30 across
interior and lower 30s across the coast.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
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Wintry precipitation lingering this morning across the region in
the morning. Freezing drizzle chances are forecast. Southern CT
will have this wintry precipitation last the longest. Winter
weather advisory ends at 11AM. By 11AM, all precipitation is
expected to be over. Dry conditions are forecast thereafter
through Monday night. Temperatures are forecast to be around
seasonable levels Sunday and Sunday night and then trend lower
than normal for Monday and Monday night.
Nearly zonal upper level jet remains across the region with
intensifying jet streak moving in Monday night.
Mid level shortwave moves northeast of the region. Mid level zonal
flow remains through Monday night.
At the surface, the low moves east of the 40N/70W benchmark Sunday.
The low accelerates and deepens to southeast of the Canadian
Maritimes by Sunday night. Meanwhile, an area of high pressure
builds into the region from the west Sunday afternoon.
The high pressure area will continue building into the region Sunday
night through Monday night. The center of the high pressure area
moves into region Monday night.-- End Changed Discussion --
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
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Zonal flow aloft for Tuesday and Tuesday night will help keep a weak
area of low pressure to our south as it develops near the Mid-
Atlantic coast and heads east into the western Atlantic. The right-
entrance region of a strong upper jet streak will be over us and
allow for expansion of the low`s precip shield into the forecast
area. Light snow likely Tuesday night for approx the southern two-
thirds of the forecast area with a 50% chance of snow for the
northernmost zones. Snow accumulations would be up to an inch.
Surface high pressure builds to our northeast during Wednesday with
upper confluence. Thinking is that surface ridging over here will be
strong enough to hold off any precipitation through the daytime
hours and this is supported by model qpf field trends, but decided
to leave in a slight chance of snow for some areas. Precip is then
expected Wednesday night and Thursday with a familiar pattern of
primary low pressure passing to our NW while a weaker secondary low
shifts through the forecast area. This would send an elevated warm
nose through, changing snow to a wintry mix Wednesday night before
an eventual changeover to rain on Thursday as enough warm air pushes
in. Right now it appears that snow/sleet accumulations would be on
the light side before the changeover to rain. Can`t rule out a
little freezing rain well NW of the city either.
Colder air filters back in from the NW Thursday night as high
pressure builds back in behind the departing storm with lingering
rain showers at the coast and snow showers or mixed rain/snow
showers inland. Dry weather then expected for Friday and Friday
night with high pressure in control. Another storm may then bring a
wintry mix to the area by the end of Saturday.-- End Changed Discussion --
&&
.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
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Low pressure tracking through the Ohio Valley allows a leading warm
front to approach this evening, with a secondary low developing
south of Long Island tonight.
VFR thru remainder of the afternoon, then sub VFR into Sunday AM.
For NYC metros and KISP, light snow begins to develop toward or
shortly after 00Z with vsbys quickly lowering to MVFR then IFR.
Precip mixes with and changes to sleet around 3Z. The snow/sleet
then transitions to freezing rain/sleet, tapering as freezing or
plain drizzle into early Sunday morning.
For Hudson Valley/CT terminals, snow arrives by 3Z, with flight
categories also lowering quickly to IFR/LIFR. The precipitation is
expected to be mostly snow, with a period of sleet possible,
particularly at KHPN, before tapering off to either light snow or
freezing drizzle Sunday AM. Conditions begin to dry out from west to
east toward 12Z and thereafter, with conditions returning to VFR at
all terminals by afternoon.
Light flow is becoming SE by late this afternoon as the high shifts
offshore, then backing NE overnight. Flow goes NW as the system
exits into late Sunday morning, with speeds increasing 10-15G25kt.
Airport Snow/Sleet Accumulations:
JFK/LGA/EWR/TEB/ISP: 3-5.
HPN/SWF/BDR/GON: 5-7.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Amendments likely this evening and overnight with changing flight
categories.
LIFR conditions possible at times into early Sunday AM.
.OUTLOOK FOR 12Z SUNDAY THROUGH THURSDAY...
Sunday: MVFR early, becoming VFR by noon. NW winds G20-25kt.
Monday: VFR.
Tuesday: Chance of snow in the afternoon, becoming likely at night.
IFR/LIFR conditions possible.
Wednesday: Chance of light snow/MVFR or lower cond, especially early.
Thursday: MVFR/IFR or lower with RA/SN.
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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Mainly sub-SCA conditions expected through tonight, although
there is forecast to be some occasional 25 kt gusts with low
pressure strengthening offshore overnight into early Sunday
morning.
Otherwise, synoptically, a more steep pressure gradient set to
develop behind low pressure Sunday into Sunday night. More
widespread SCA gusts are expected to develop on the ocean waters
Sunday and extend into Sunday night, especially for more eastern
ocean waters. Ocean seas will build to 5 to 6 ft Sunday also,
also lingering into Sunday night, farther into Sunday night east
of Fire Island Inlet.
With high pressure moving closer to the local waters, eventually
sub-SCA conditions expected to return to the ocean waters by
early Monday morning. Sub-SCA conditions then expected on all
waters through Monday night.
Winds and seas will remain below advisory criteria across all the
forecast waters with a weak pressure gradient Tuesday into
Wednesday. An onshore flow then increases Wednesday night into
Thursday morning with the approach of low pressure approaching from
the south and west. Advisory-level gusts anticipated on all waters
during this period with even a chance of a gust or two approaching
gale force for a brief period on the ocean waters. Winds then shift
offshore Thursday afternoon after a brief lull before increasing
once again Thursday night with SCA conditions probable on all
waters.-- End Changed Discussion --
&&
.HYDROLOGY...
There are no hydrologic concerns through the forecast period.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Winter Storm Warning until 11 AM EST Sunday for CTZ005>012.
NY...Winter Storm Warning until 11 AM EST Sunday for NYZ067>070.
Winter Weather Advisory until 11 AM EST Sunday for NYZ071>075-
078>081-176>179.
NJ...Winter Storm Warning until 11 AM EST Sunday for NJZ002-103.
Winter Weather Advisory until 11 AM EST Sunday for NJZ004-006-
104>108.
MARINE...Small Craft Advisory from 7 AM Sunday to 3 AM EST Monday for
ANZ350-353.
Small Craft Advisory from 7 AM to 9 PM EST Sunday for ANZ355.-- End Changed Discussion --
&&
$$
SYNOPSIS...JC/JM
NEAR TERM...JM/MW
SHORT TERM...JM
LONG TERM...JC
AVIATION...DR
MARINE...JC/JM
HYDROLOGY...JC/JM