124
FXUS61 KOKX 160331
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
1031 PM EST Sat Feb 15 2025
.SYNOPSIS...
-- Changed Discussion --
A low pressure system impacts the local area as it passes to the
northwest on Sunday and then to the north Sunday night. A
strong cold front will pass through behind the low late Sunday
afternoon into the early evening. Low pressure spins over the
Canadian Maritimes on Monday. Strong high pressure dives south
into the middle of the country Tuesday into Wednesday and
gradually noses in. Low pressure then emerges out off
Southeastern US coast. This low strengthens as it lifts
northeast along and just off the Mid Atlantic coast Thursday.
The low pulls away Thursday night with high pressure building
into next weekend.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --
Melting layer as seen KOKX radar is currently over the northern
portions of the Lower Hudson Valley, heading east over the
over toward New Haven county in CT, then southeast along the New
Haven/Middlesex border, and just east of the Twin Forks. Snow
should continue north and east of this line as it continues
moving northeast. Southwest of this line, where surface
temperatures have risen to above freezing, precipitation will be
plain rain. Southwest of this line, where temperatures are at or
below freezing, any combination of a wintry mix of snow, sleet,
and freezing rain is expected. Some of the more southern spots
where the Winter Weather Advisory is in effect (portions of
northeast New Jersey, souther portions of the Lower Hudson
Valley, and coastal Connecticut) are seeing temperatures rise
above freezing, however enough observations were at or slightly
below freezing to keep the advisory in effect. Increased ice
amounts across the advisory areas as these areas are well into
the 20s and a northerly flow will continue to advect colder air
(or at least keep temperatures steady despite the thermodynamic
warming effect of the environment associated with freezing
precipitation) into those areas for quite a few hours. Up to
1/4" of ice is possible, and potentially more. This could lead
to some isolated power outages if that amount of ice is
realized. Current radar shows light to moderate precipitation
developing over northern Orange county, so this would be the
location to expect the higher amounts of ice.
A deepening surface low will continue to impact the local area
as it approaches the eastern Great Lakes through Sunday
morning, sending a warm front towards the area.
Still looking at snowfall totals across NYC and LI between 1-2
inches before a changeover to rain this evening. To the north
and west where winter weather advisories remain in effect,
expect anywhere from 2 to 4 inches. The upper end of these
ranges will be closer to I-84 and some of the higher terrain
areas well inland.
High temperatures in upper 20s to low to mid 30s will continue
to gradually warm up through the overnight hours. By daybreak,
areas well inland will be in the lower to mid 30s, with LI and
the NYC around 40.-- End Changed Discussion --
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Low pressure is forecast to be west of the area Sunday morning
with the associated warm front near or just south of LI. The
first shot of warm advection precipitation will lift to the
north and east with a secondary surge of warm advection as a
southerly LLJ approaches from the south, strongest to the south
and east of LI, with the potential for 75 to 85 kt just a few
thousand feet. Airmass will be strongly inverted and any mixing
of higher winds from aloft will likely not to happen until late
in the afternoon as the cold front approaches from the west and
the inversion erodes. With the warm front still in close
proximity, strong thermal forcing both in the warm sector and to
the north should allow for more a convective type of rainfall.
Rainfall during this time will be moderate to occasionally
heavy with the best thermal forcing across eastern LI and SE CT.
By the time the cold front passes late afternoon/early evening,
much of the area is forecast to have received 1.5 to 2 inches
of liquid equivalent, with the highest amounts across LI and CT.
A high wind watch continues for the entire area Sunday night
into Monday. Just ahead and behind the cold front, there is the
potential for wind gusts of 40-50kt, especially with the
pressure rises immediately behind the cold front. Winds at the
top of mixed layer will be around 50 kt, and on average about 40
kt through the layer. Thus, high winds are possible through the
overnight, aided by strong cold advection and cyclonic flow.
Temperatures will fall back below freezing and into the 20s by
daybreak Monday.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
* Windy with the potential for strong winds on Monday.
* The potential remains and has increased some for a significant /
major winter storm in the Wed night - Thursday night time frame.
Windy conditions continue as a strong pressure gradient remains over
the area due the departing low that will spin over the Canadian
Maritimes on Monday and strong arctic high pressure (1050-1054 mb)
that builds in from southern Canada. W winds of up to 25 mph are
forecast, with gusts around 40 mph in the morning. Winds diminish
late in the morning into the afternoon as the pressure gradient
relaxes a bit.
The high continues to nose in from the north and west Tuesday and
Wednesday, keeping the region dry. As the arctic air moves south, a
baroclinic zone sets up over the southern states, allowing low
pressure to begin to take shape. This low then treks east along the
gulf states, and ejects off the Southeast US coast Wednesday night,
then tracks northeast into Thursday, pulling away from the area
Thursday night.
With the current deterministic model suite, most models track the low
around or just east of the 40/70 benchmark, a favorable track for an
all snow event. Current NBM forecast also shows an all snow
forecast, leading to higher confidence in an all snow event. Despite
confidence increasing in an all snow event, the exact track of the
low still remains in question. If the low pushes to far east, it
will take the majority of the precipitation with it, and thus, snow
will be much less and limited to the coast.
As for ensembles, current ECMWF ensemble give coastal areas a 30-40%
chance of 24 total precip of great than half an inch liquid
equivalent, while the same metric is only 10-20% with the GFS
ensemble. Current NBM is closer to the ECMWF ensemble. The finer
details will be ironed out as we get closer to the event, and more
of the higher resolution models come into play.
While it is too early to give snowfall forecast for this event, GEFS
plumes show a mean of about 2.5" for KISP, while the GFS
deterministic is about 9.0" for the event, with a fair number of
members below the 2.5" mean. This underscores the uncertainty with
this upcoming event.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Low pressure and a warm front will approach tonight. The low
will pass west and north on Sunday, with the warm front in the
vicinity Sunday morning, followed by a strong cold frontal
passage late in the day.
Snow has changed to rain or a rain/sleet mix at the NYC metros.
Precip should change to rain this evening at KISP and over to
freezing rain at KHPN/KSWF.
Overall, conditions remain IFR/LIFR. LIFR will be more likely
daytime Sunday as the warm front approaches.
Winds mostly SE less than 10 kt should become E-NE overnight.
With the warm fropa most spots should shift SE then S late in
the afternoon, then WSW late and become gusty with cold fropa.
LLWS likely in the afternoon from the NYC metros east.
Additional snow accumulation of 1-2 inches possible at
KSWF/KBDR/KGON.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
AMD likely for fluctuations in flight category.
.OUTLOOK FOR 00Z MONDAY THROUGH WEDNESDAY...
Sunday night: Becoming VFR with cold fropa. Gusty SW winds
becoming W, G40-50kt.
Monday: VFR. W winds G35-40kt, diminishing at night.
Tuesday: VFR. W winds G25 kt.
Wednesday: VFR.
Wednesday night: Becoming IFR in snow.
Thursday: IFR/LIFR in snow. NE winds G20kt, becoming NW G25kt at
night.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
High pressure over the waters weakens and then dissipates to
the east through tonight. A storm system will impact the area
with a strengthening southerly flow on Sunday, followed by
strong west winds Sunday night. A gale warning has been posted
for all waters Sunday afternoon through the first half of Monday
night with a storm watch issued for the eastern ocean zone
Sunday afternoon through Monday afternoon. Seas will build to 5
to 8 ft on LI Sound and 10 to 18 ft on the ocean waters
overnight Sunday.
Gale conditions across all waters on Monday with potential Storm
force gusts for the eastern ocean zone, in the wake of a storm
moving through the Canadian maritimes. High ocean seas of 7 to 16 ft
Monday morning, diminish through the day, but remain above SCA
conditions across all waters through Tuesday. Non ocean waters drop
below 25 kt late in the day/Tuesday evening, while ocean water gusts
will diminish from west to east Tuesday night.
Sub-SCA conditions expected across all waters Wednesday and much of
Thursday. Winds increase a coastal low impacts the waters late in
the day, with SCA conditions over oceans waters first late Thursday,
then across all waters Thursday night.
&&
.HYDROLOGY...
No hydrologic impacts are anticipated from this weekend`s storm
system despite the fact that 1.5 to 2 inches of liquid is expected
across the area. Thereafter no hydrologic impacts are anticipated
through the remainder of the forecast period.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 7 AM EST Sunday for CTZ005>008.
High Wind Watch from Sunday evening through Monday afternoon
for CTZ005>012.
Winter Weather Advisory until 1 AM EST Sunday for CTZ009>012.
NY...Winter Weather Advisory until 7 AM EST Sunday for NYZ067-068.
High Wind Watch from Sunday evening through Monday afternoon
for NYZ067>075-078>081-176>179.
Winter Weather Advisory until 1 AM EST Sunday for NYZ069>071.
NJ...Winter Weather Advisory until 7 AM EST Sunday for NJZ002.
High Wind Watch from Sunday evening through Monday afternoon
for NJZ002-004-006-103>108.
Winter Weather Advisory until 1 AM EST Sunday for NJZ004-
103>105.
MARINE...Gale Warning from 4 PM Sunday to midnight EST Monday night for
ANZ331-332-335-338-340-345.
Gale Warning from 11 AM to 6 PM EST Sunday for ANZ350.
Storm Watch from Sunday evening through Monday afternoon for
ANZ350.
Gale Warning from 11 AM Sunday to midnight EST Monday night
for ANZ353-355.
&&
$$
SYNOPSIS...
NEAR TERM...JP
SHORT TERM...
LONG TERM...JP
AVIATION...BG/MET
MARINE...
HYDROLOGY...