discussion on 2024-01-19

000
FXUS61 KOKX 200031 CCA
AFDOKX

Area Forecast Discussion...CORRECTED
National Weather Service New York NY
731 PM EST Fri Jan 19 2024

.SYNOPSIS...
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.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
At 700 PM EST light snow has ended across much of the area, with
the back edge moving through the south, and east portion of
Suffolk County. Surface low pressure was located south of Nova
Scotia and will move east as high pressure builds to the west
through the overnight.

A Special Weather Statement, for the entire area, was updated
to just mention the potential for icy conditions to develop,
especially on untreated surfaces. With temperatures dropping
into the teens, any residual moisture will freeze.

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.

&&

.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 /00Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --Low pressure pulls away from the region tonight as high pressure
gradually builds in from the west through the weekend.

Mainly VFR, but spotty MVFR conditions are still possible for
the next hour or two, especially for KISP and KGON.

N-NW winds around 10 kt will become predominantly NW with gusts
to around 20kt developing overnight. This may be more
occasional outside of the NYC terminals. Gusts will increase to
around 25kt kt on Saturday with a few higher gusts possible,
especially in the afternoon.

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

Chance of gusts up to 30 kt on Saturday afternoon into early
evening.

OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY...

Saturday Night-Sunday...VFR. N-NW wind gusts 20-25kt. A few
higher gusts possible Saturday evening.

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 remains in effect for all waters tonight
through Saturday night. 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...DW
MARINE...MET/JT
HYDROLOGY...MET/JT