959
FXUS61 KOKX 181202
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
702 AM EST Tue Feb 18 2025
.SYNOPSIS...
High pressure builds from the west through Wednesday. Deepening
low pressure off the Mid Atlantic coast Thursday will pass well
south and east of the area through Thursday night. A large area of
high pressure over the mid section of the country will then build
east through the upcoming weekend. Weak low pressure then
approaches from the Great Lakes early next week.
&&
.NEAR TERM /THROUGH TONIGHT/...
Cold and brisk conditions continue today with the region between
deep low pressure well to the north and east, and a strong high
centered near the Northern Plains.
Temperatures in the teens to mid 20s this morning, though wind
chills near zero in some locales. With the cold air mass entrenched,
anomalies run 10 to 15 degrees below normal. After the frigid start,
afternoon tops out a few degrees colder than Monday, with highs
generally in the mid to upper 20s and wind chills in the teens.
Dry conditions prevail with the building high under a mix of clouds
and sunshine. Mixed layer continues to extend toward or above
850 mb thru the day, which helps to allow W or WNW gusts to
remain gusty, generally 30 to 35 mph, but isolated gusts could
exceed 40 mph at times. Flow should finally gradually start to
weaken this evening and overnight as the high shifts closer and
the low exits out into the North Atlantic.
Low temperatures overnight likely a few degrees colder than the
previous night, single digits far interior, to teens along the
coast. A lighter flow should buoy wind chills a bit, but still
near zero or below at times.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Strong >1050 mb Arctic high pressure continues to build in from
the west Wednesday, keeping the region dry.
Remaining cold, region largely sub freezing with highs in the
upper 20s to around 30. Winds are expected to be lighter than
previous days with the high more established and a relaxed
pressure gradient in response.
Closed upper low trough digs south of the Great Lakes into
late Wednesday, spurring a surface low pressure to develop over
the South, before pushing offshore Wednesday night. Expecting a
high and mid level deck to develop locally with the associated
moisture advection, but remaining dry thru the period.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
* Deepening low pressure off the Mid Atlantic coast Thursday likely
passes far enough south and east to spare the area a significant
snowfall.
* Remaining cold with temperatures running 5 to 10 degrees below
normal through the weekend, then a gradual warmup into early
next week.
Much of the 00Z guidance and ensembles continue to favor a
progressive southern branch low passing well south and east of the
forecast area Thursday into Thursday night. A northern branch upper
low over the Ohio Valley never phases with the southern branch storm
system as it moves off the northern Mid Atlantic coast Thursday
night. NBM and LREF (Long Range Ensemble Forecast) probabilities
remain very low for an advisory level event with the highest
probabilities across eastern LI. LREF is about 5-15%, while the NBM
is a bit higher at 10-25%. This is mainly for eastern portions of
Suffolk County on LI and far SE CT. For about an inch, looking at
about 20 to 50%. However, there has been slight uptick in these
probabilities. 00Z Nam12 was the most aggressive with about 0.50"
liquid equivalent, but has come down with the 06Z run. Additionally,
there is definitely a reflection of some light snow associated with
the aforementioned upper low passing nearby. Bottom line, this looks
like a light snowfall event with the event total snowfall less than
an inch. Best chance of seeing an inch or more is across far eastern
LI. Highest probabilities of snow are during the afternoon and
evening hours Thursday.
Thereafter, strong high pressure over the mid section of the country
builds east through the weekend, passing to the south Sunday. Expect
gusty NW winds late Thursday into Friday behind the deepening offshore
low. Used a blend with of the NBM and NBM90 for winds as the deterministic
is often underdone in a westerly flow. A clipper low approaches
from the Great Lakes early next week with a low chance of snow
and/or rain late Monday.
Temperatures at the start of the period will average 5-10 degrees
below normal, but then warmup to normal for Sunday and Monday.-- End Changed Discussion --
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Low pressure departs from the Canadian Maritimes and out into
the north Atlantic, while strong high pressure gradually builds
in from the west through Wednesday.
Winds will be W around 20 kt with gusts 30-35 kt today, then
gradually diminish tonight.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled AMD expected.
.OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...
Wednesday: VFR.
Thursday: Mainly VFR. Chance MVFR or lower in light snow, mainly
for the terminals east of NYC. NW winds G20-25kt at night.
Friday: VFR. NW winds G20-25 kt.
Saturday: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Gale Warning remains in effect for all waters thru this afternoon
with W or WNW gusts around 35 kt. Gusts may be more marginal
however at times, and will monitor should the warning be able to
come down sooner. Winds begin to more solidly lower under gales
by late day on most waters, likely lingering on the ocean into
this evening. Thereafter, a Small Craft Advisory will be needed
on all waters for gusts at or above 25 kt continuing into
tonight, and likely into Wednesday morning on the ocean and
perhaps eastern Sound. Then, sub SCA conditions on all water by
Wednesday afternoon. Light freezing spray possible everywhere
through Wednesday as well, but not anticipating it to be heavy
enough to necessitate an advisory.
Deepening offshore low pressure will likely bring a period of SCA
conditions to the waters late Thursday into Friday as it tracks
northeast up into the North Atlantic. SCA conditions may linger on
the ocean into the first half of Friday night. High pressure builds
in from the west for the weekend with sub-SCA conditions.
&&
.HYDROLOGY...
No hydrologic impacts are expected through the week.
&&
.TIDES/COASTAL FLOODING...
The combination of relatively strong W-WNW winds and astronomical
low tides will pose a threat of low water conditions for the low
tide cycles this morning and evening, particularly for the western
Long Island Sound and Peconic and Gardiners Bays. A Low Water
Advisory has been hoisted for these zones during the low tide cycle
this morning, with expected water levels around -2 ft MLLW.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...None.
NJ...None.
MARINE...Gale Warning until 4 PM EST this afternoon for ANZ331-332-335-
338-340-345.
Low Water Advisory until 11 AM EST this morning for ANZ335.
Low Water Advisory until noon EST today for ANZ340.
Gale Warning until 10 PM EST this evening for ANZ350.
Gale Warning until 7 PM EST this evening for ANZ353-355.-- End Changed Discussion --
&&
$$
SYNOPSIS...DR/DW
NEAR TERM...DR
SHORT TERM...DR
LONG TERM...DW
AVIATION...DW
MARINE...DR/DW
HYDROLOGY...DR/DW
TIDES/COASTAL FLOODING...