000
FXUS61 KOKX 162225 CCA
AFDOKX
Area Forecast Discussion...CORRECTED
National Weather Service New York NY
525 PM EST Tue Jan 16 2024
.SYNOPSIS...
The wave of low pressure moves into Gulf of Maine this evening.
The low moves into the Canadian Maritimes later tonight into
early Wednesday. High pressure will start to build in from the
south and west late tonight into Wednesday. The high moves east
and continues to build in Wednesday night. High pressure slides
offshore Thursday. Low pressure then strengthens off the
Carolina coast Thursday night, passing south and east of the
area Friday. High pressure slowly builds in this weekend and
remains in control through early next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --
As the wave of low pressure traverse from Gulf of Maine to the
Canadian Maritimes tonight, it will deepen. This will steepen the
pressure gradient. Strong cold air advection will follow.
Temperatures are forecast to lower more from NW to SE across the
area as winds become more NW and increase, with atmospheric column
cooling. However, with surface to 7-8 kft above still having much
moisture, looking for some snow to redevelop and allow for snow
to mix back in from west to east going into the first hour of this
evening. Would expect the wintry mix to have more snow before all
precipitation tapers off.
Precipitation is expected to be over by 6 to 7pm. Forecast lows
are going to be in the lower teens to near 20. Wind chills will
be dropping into the single digits to near 10 late tonight for
much of the region.
With temperatures going well below freezing, any leftover
moisture will freeze and any snowmelt will refreeze.
Icy surfaces tonight for anywhere that is untreated making for
slippery conditions. Also, winds not too gusty so while some
moisture will dry up, still think there will be many locations
with residual moisture and snowmelt that will become frozen
tonight. SPS has been issued for the entire area to account for
this.-- End Changed Discussion --
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
Dry conditions prevail but temperatures will be very cold and
well below normal.
Mid level flow transitions to more zonal. Surface high pressure
builds in from the south and west. Very cold 850mb temperatures
decrease to near -14 to -15 degrees C.
Mid level negative vorticity advection should allow for more sun
Wednesday but despite this, temperatures will remain very cold.
The gusty westerly flow will continue. With the aforementioned
very cold 850mb temperatures, daytime highs with daytime mixing
only are expected to reach the mid 20s to lower 30s.
High pressure still builds in Wednesday night but its center
remains far removed from the local area. The pressure gradient
still remains tight enough to allow for gusty winds along the
coast with winds decreasing more away from the coast. Similar low
temperatures to those of the previous night are forecast, ranging
once again from the lower teens to near 20.-- End Changed Discussion --
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
* KEY POINTS *
* Potential for a light snowfall Friday into Friday night
* Coldest airmass of the season builds in for the weekend
High pressure slides offshore early on Thursday and heights briefly
rise aloft. Thursday will feature decreasing winds with temperatures
about 5 to 10 degrees below normal.
Attention then turns to a coastal low that has potential to bring a
light snowfall to the area Friday into Friday night. Low pressure
will strengthen off the Carolina coast and track north, passing our
area to the south and east. There remains uncertainty with the exact
track in the latest guidance. However, with enough cold air in
place, most of the current track solutions would bring a widespread
light accumulating snowfall to the area. The 50th percentile storm
total QPF from the 12z LREF members was about 0.15 inches across the
area, with any of the higher outliers coming from some GEPS members.
The current forecast has about 2 inches of snow across the southern
half of the area and an inch for the northern half taking the QPF
forecast and using a snow ration of 14+:1. A closer solution doesn`t
necessarily bring the concern for rain at the coast, like with other
systems this year, it would likely instead bring higher snowfall
totals. Right now the NBM only has a 20% for an advisory level
snowfall (3 inches) across the southern half of the area.
Behind this system high pressure slowly builds in through the
weekend, bringing in the coldest airmass of the year. The pressure
gradient will be tight over the area leading to windy conditions. 30
mph gusts are expected Saturday through Sunday. The winds combined
with the cold temperatures will bring low wind chill values. Minimum
wind chill values Friday night and Saturday night will be below 0
for most, with the low single digits for NYC. Maximum wind chill
values during the day on Saturday will be in the mid single digits
to the low teens for most. A slow warming trend starts after
Saturday and by Tuesday highs will be back in the low 40s. High
pressure remains in control through Tuesday.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
Low pressure passing east of the region moves northeast into tonight
as high pressure begins building in from the southwest.
MVFR or IFR with a wintry mix through about 22-00Z. Improvement to
VFR after 00Z.
Wintry mix of FZRA, PL, and SN near the coast will continue before
ending 22-00Z. Some minor ice accretion is possible through the
early evening. Precip ends with VFR conditions expected after 00Z.
N flow shifts toward the NW this evening. NW flow increases with 20-
25 kt gusts developing by 00Z, lingering into the overnight. Wind
gusts may subside after 06Z but expected to increase again by mid-
morning as the wind shifts to the W.
NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Uncertainty with timing of precip type changes and precip ending
through 00Z.
OUTLOOK FOR 21Z WEDNESDAY THROUGH SUNDAY...
Wednesday Afternoon: VFR. W wind gusts 20-25 kt.
Thursday: Mainly VFR. W wind gusts 15-20 kt during the day.
Friday...IFR with snow likely, mainly during the day. Chances for
snow lower at night. NE-N wind gusts 20 kt in the afternoon and at
night.
Saturday...Mainly VFR. N-NW wind gusts 25-30 kt.
Sunday...Mainly VFR. N-NW gusts 20-25kt.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
-- Changed Discussion --
With colder air advecting in on the relatively warmer waters,
gusty winds to SCA levels should easily materialize across all
waters tonight. SCA is in effect for all waters tonight.
For Wednesday, with high pressure building in, some decrease in
winds is forecast for the early part of the day. Gusts to SCA
levels remain for the ocean while the non-ocean waters are only
expected to gust to near 20 kt. Forecast for wind gusts for
non-ocean zones increases back to 25 kt but not until mid to
late afternoon Wednesday. So SCA only remains for the ocean
Wednesday.
For Wednesday night, gusts increase all waters, with likely SCA
wind gusts. The ocean already has SCA going through Wednesday
night but non-ocean waters may very well need another SCA for
this time period.
In addition, with the very cold air and gusty winds, there will
be a chance for light freezing spray for the ocean waters and
Eastern Long Island Sound late tonight and on Wednesday.
Winds lower Thursday with sub SCA conditions returning to non
ocean waters early in the day, and on the ocean by Thursday
night due to lingering 5 ft seas.
SCA conditions redevelop late Friday or Friday night, and may
persist on all waters through the weekend under NW flow. Sub SCA
conditions then expected through much of early next week.-- End Changed Discussion --
&&
.HYDROLOGY...
No hydrologic impacts are expected through the forecast period.
&&
.TIDES/COASTAL FLOODING...
With high tide passed, water levels along the shoreline are
expected to remain below minor coastal flood benchmarks.
Westerly flow tonight through Wednesday night will keep these
water levels well below minor coastal flood benchmarks.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory until 7 PM EST this evening for
CTZ005>012.
NY...Winter Weather Advisory until 7 PM EST this evening for
NYZ067>075-078-080-176>179.
NJ...Winter Weather Advisory until 7 PM EST this evening for NJZ002-
004-006-103>108.
MARINE...Small Craft Advisory until 6 AM EST Wednesday for ANZ331-332-
335-338-340-345.
Small Craft Advisory until 6 AM EST Wednesday for ANZ350-353-
355.
&&
$$
SYNOPSIS...JM/JT
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...JT
AVIATION...MW
MARINE...JM/JT
HYDROLOGY...JM/JT
TIDES/COASTAL FLOODING...JM