discussion on 2024-01-19

000
FXUS61 KOKX 192220
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
520 PM EST Fri Jan 19 2024

.SYNOPSIS...
-- Changed Discussion --Low pressure departs to the east tonight. Arctic high pressure
then builds in through the weekend, and slides to the south of
Long Island Monday. A frontal system impacts the area Tuesday
through Wednesday night, with another quickly following from the
southwest for Thursday and Friday.-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
-- Changed Discussion --Updated for the ending of the light snow to the north.

A Special Weather Statement remains in effect for the entire
area for some lingering light snow through the evening commute,
as well as the potential for icy conditions through tonight.
With temperatures dropping into the teens, any residual moisture
will freeze. Untreated surfaces will become icy.

The heaviest snowfall has already fallen and only lingering light
snowfall is expected through early this evening. Current MRMS
and OKX radar show returns lightening across the area,
especially to the north. The low continues to be seen quite
well on visible satellite imagery and is now about 375 nm
southeast of Long Island. An inverted trough stretches back
west, well to our south.

Attention now turns to arctic high pressure that will build in
from the west. This will bring us the coldest airmass of the
season. As the ~1040mb high builds in, the exiting low
strengthens. This will place the area under a tight pressure
gradient. Winds will increase to about 15 to 20 mph tonight.
This combined with the cold temperatures will cause wind chill
values to be in the single digits tonight, with sub zero values
across the interior.-- End Changed Discussion --

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
The high continues to build in on Saturday, with the area remaining
in a tight pressure gradient. This will allow for cold conditions
Saturday and Saturday night. Highs on Saturday top out in the low to
mid 20s. With winds staying around 15 to 20 mph, max wind chill
values during the day will be in the low teens, meaning most of the
day will feature single digit wind chill values. Saturday night
will similar to Friday night, just a few degrees colder. Some
sub zero wind chill values could be seen across eastern Long
Island.

Skies start to slowly clear Saturday night as the upper level
trough axis finally shifts east.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
The long term period will feature below normal temperatures
continuing, Sunday into Monday, with a warm up beginning Monday
night, and temperatures rebounding to above normal for Tuesday
through Friday.

Arctic high pressure continues to build toward the region from the
west Sunday, and then builds to the south, off the Mid Atlantic
coast, Monday night into Tuesday. Sunday and Sunday night
temperatures will be 5 to near 10 degrees below seasonal normals.
While warm advection does not set up until Tuesday, with the
approach of a warm front, the airmass will be modifying during
Monday as temperatures rise to near normal levels.

A weak surface trough, or cold front, with little moisture,  moves
into the region early Tuesday and becomes nearly stationary during
the day. Warm advection then sets up later Tuesday and continues
through the week as the frontal boundary remains in the vicinity. A
series of southern stream shortwaves will bring waves of low
pressure along the front Tuesday into Wednesday, with another
Thursday into Friday. With an highly anomalous warm airmass moving
into the region, with temperatures rising to 10 to 15 degrees above
normal, used a blend of the NBM, and 75th percentile for
temperatures Tuesday through Friday to better capture the unusual
warmth.
Precipitation will be mostly rain across the region, with a mix of
rain and snow inland Tuesday into early Wednesday.

&&

.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --Low pressure pulls away from the region tonight as high
pressure gradually builds in from the west through the weekend.

Widespread MVFR/IFR conditions will persist through early evening.
Light snow (-SN) is resulting in visibilities anywhere from 1 to 3
miles for much of the area and should gradually improve as the light
snow continues to diminish through the evening. Light snow and
flurries will end between 22-00Z. VFR conditions expected around or
shortly after 00Z for the NYC terminals with eastern terminals going
VFR a few hours later.

NNE winds around 10kt will veer to the N by early evening, then NW
after 00Z. Second half the night and Saturday will feature gusts up
to 20-25 kt.

   NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

Amendments possible for the timing of improving flight categories
through this evening.

OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY...

Saturday afternoon-Sunday...Mainly VFR. N-NW wind gusts 20-30kt.

Monday...VFR.

Tuesday...Mainly VFR. Possible MVFR or lower in any rain/snow
showers.

Wednesday...MVFR or lower possible in rain.

Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --

&&

.MARINE...
A Small Craft Advisory is in effect for all waters tonight through
Saturday night. The Saturday night Gale Watch has been converted to
a Small Craft Advisory as wind gusts have trended down. Winds in the
SCA will generally be 25 kt, with 25 to 30 kt expected late Saturday
into Saturday night. With a cold airmass building in, Air temperatures
are forecast to be in the teens to 20s and water temperatures in
the lower upper 30s to lower 40s. This combined with the forecast
winds will allow for a chance of light vessel ice accumulation
starting tonight. This will mainly be across the ocean zones and
the LI Sound.

High pressure will be building in from the west Sunday as low
pressure departs to the northeast. A strong pressure gradient force
will remain across the waters Sunday as a strong and gusty northwest
flow persists. Small craft advisory gusts will likely be on-going
Sunday morning across the forecast waters. Ocean seas may be near 5
feet early Sunday morning, then subside in the northwest flow. Winds
and gusts diminish through the day as the high builds closer to the
waters. And during Sunday evening gusts will likely fall below 25
knots.

The high shifts to the south of the waters Monday with a cold front
approaching from the north. A west/southwest flow will be increasing
through Monday, and by late in the day, or early Monday evening
gusts and seas on the ocean waters may reach SCA levels. There is
some uncertainty as to how much mixing will occur over the waters
as warmer air flow in and keeps a low level inversion in place.
Early Tuesday gusts and seas fall below SCA levels as a weak cold
front becomes nearly stationary in the vicinity. Winds and seas then
remain below advisory levels on all the waters late Tuesday through
Wednesday.

&&

.HYDROLOGY...
No hydrologic impacts are expected through the end of next week.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from midnight tonight to 6 AM EST Sunday
     for ANZ331-332-335-338-340-345.
     Small Craft Advisory until 6 AM EST Sunday for ANZ350-353-355.

&&

$$

SYNOPSIS...MET/JT
NEAR TERM...MET/JT
SHORT TERM...JT
LONG TERM...MET
AVIATION...MW
MARINE...MET/JT
HYDROLOGY...MET/JT