000
FXUS61 KOKX 142243
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
543 PM EST Thu Dec 14 2023

.SYNOPSIS...
Strong high pressure will remain centered over the Mid Atlantic
states through Friday, then will be reinforced by a second area
of high pressure building across eastern Canada. High pressure
shifts off the New England coast Saturday night. Low pressure
impacts the area Sunday through Monday. Another low may linger
nearby Tuesday and Wednesday. High pressure then builds in on
Thursday.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --
The forecast is on track this evening. Minor adjustments were
made to the forecast to capture the current obs and trends.

A broad area of low pressure encompassing much of central and
eastern Canada will send a warm front through the area dry
tonight. It will also allow for a strengthening W/SW flow
which should limit strong radiational cooling under clear
skies. Lows tonight will generally be in the upper 20s to the
lower 30s, except the mid 30s for the NYC metro. This is close
to normal.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY/...
High pressure will remain nearly stationary over the central
Appalachians on Friday, while a broad area of low pressure
tracks across eastern Canada. There could be a few gusts up to
20 mph in the WSW flow, especially into early afternoon. Behind
the low to the north, high pressure builds across eastern
Canada, merging with the high to the south. A weak backdoor
cold front passes through the area Saturday morning, allowing
for west winds to veer to the NNE at less than 10 mph. The center
of the high tracks into northern New England Saturday evening.
Some mid and high levels clouds ahead of the next weather system
will begin to filter into the area late Saturday.

As for temperatures, a strong subsidence inversion over the
area on Friday will limit mixing with highs mainly in the lower
50s, but it will be a few degrees warmer across metro NE NJ.
Lows Friday night will be in the lower to mid 30s, but closer to
40 for the NYC metro. Highs on Saturday will be a bit cooler in
the N/NE flow with highs around 50.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
There is decent overall agreement across the global deterministic
guidance through Monday night. The period starts off with high
pressure, centered over Maine, shifting east. A low pressure system
then approaches from the south and impacts the area Sunday through
Monday. There is then disagreement on a lingering low or high
pressure building in, both leading to very different weather
conditions. The forecast Monday night and on is lower confidence.

Low pressure is progged to develop over the Gulf of Mexico sometime
late Friday into Friday night under a southern stream shortwave.
This low then lifts and deepens as it interacts with another
shortwave diving down from the central CONUS. The low continues up
the east coast and tracks over or near the area. Latest 12z
deterministic guidances has shifted slightly farther east with the
center track. This system will bring heavy rain and gusty winds to
the area, as well as the potential for coastal flooding (see coastal
flooding section below). Chances of rain start as early as Sunday
morning, but don`t become likely until the afternoon. By Sunday
night rain will be moderate to locally heavy as a LLJ strengthens
and approaches. A widespread 2-2.5 inches is expected at this time.
See hydrology section below. As for winds, peak gusts will be Sunday
night into Monday morning. Strongest will be across the coast, with
the potential of 30-35 mph across most coastal locations, 40-50 mph
for eastern Long Island.

As previously mentioned, the forecast confidence lowers after Monday
night. This is due to the interaction of a northern stream trough
with the weekend system and how the guidance is responding. The
ECMWF and Canadian close this trough and the upper level low lingers
over the area along with associated surface low. This then results
in lingering precipitation chances through Wednesday. The GFS shows
an upper level low well southeast of the area, with broad high
pressure building in. Given the spread in guidance, stuck close to
NBM.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR as strong high pressure remains off to the west. A dry warm
front will pass through early this evening.

Winds are in process of backing to the SW tonight, with some
variability in direction between 250-310 true possible for the next
hr or two as this takes place. Otherwise high confidence in winds
tonight into Fri AM.

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

Wind direction could vary between 250-310 true before 22Z at
KJFK/KLGA.

OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...

Friday afternoon through Sunday morning: VFR.

Sunday afternoon: Rain likely with MVFR or lower cond. E winds
G20kt NYC metro/coastal terminals.

Sunday night and Monday: IFR in rain, possibly heavy at times.
SE winds G30+ kt along the coast and LLWS. Winds shift to S
Monday afternoon, then shift SW and diminish Mon night.

Tuesday: Chance of rain with MVFR or lower cond. NW winds G20kt.

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

&&

.MARINE...
A SCA is in effect for the ocean waters later tonight into
Friday with west gusts around 25 kt and seas of 3 to 6 ft.
These conditions subside by Friday evening as high pressure
builds in from the west. Sub-SCA conditions continue through
Saturday.

Sub-SCA conditions continue through at least the first half of
Sunday. Winds and waves then increase as low pressure approaches and
impacts the area. SCA conditions can be expected on all waters by
Sunday night. Winds look to peak late Sunday night into early Monday
morning. Across the ocean zones and eastern Sound zone gusts up to
35 kts are forecast. Across all other zones, gusts likely peak at 25
to 30 kts. Waves across the ocean zones peak Monday morning through
Monday at 14 to 18 ft. Waves remain below 5 ft elsewhere, except the
eastern Sound zone which can see waves up to 10 ft and the NYC
harbor which can see up to 5 ft. SCA conditions continue on all
waters through Monday.

Beyond Monday night model guidance spread increases. This leads to a
low confidence win forecast Tuesday through Thursday. At this time,
winds are forecast to remain below 25 kt, but SCA conditions
continue on the ocean waters with elevated wave heights.

&&

.HYDROLOGY...
Chances of rain start as early as Sunday morning, becoming likely by
Sunday afternoon and continuing through Monday. The rain is expected
to be moderate, with periods of heavy rain, Sunday night through
Monday morning. At this time, a widespread 2 to 2.5 inches of
rain is expected, with locally higher amounts possible. Flash
flooding potential remains low at this time, but minor
urban/small stream flooding is possible. Given recent rainfall
there is also an elevated threat for river flooding.

&&

.TIDES/COASTAL FLOODING...
A coastal low has the potential to bring coastal flooding to
the area during the high tide cycles late Sunday night into
Monday. The forcing will be a strengthening S/SE flow that may
bring a prolonged period of gale force gusts. There still
remains some uncertainty with the timing and track of the low
which will be crucial for the extent and magnitude of the
event. Right now, there is a good chance of widespread minor to
localized moderate coastal flooding across Lower NY Harbor and
the south shore back bays of western LI. SW CT also has a good
chance of minor coastal flooding with an isolated potential
elsewhere. A limiting factor will be low astronomical tides
being between a full and new moon. This will be refined as we
get closer to the event and there is better run-to-run
continuity of the guidance.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 11 PM this evening to 6 PM EST
     Friday for ANZ350-353.
     Small Craft Advisory from 11 PM this evening to 4 PM EST
     Friday for ANZ355.

&&

$$

SYNOPSIS...JT/DW
NEAR TERM...JT/DW
SHORT TERM...DW
LONG TERM...JT
AVIATION...BG
MARINE...JT/DW
HYDROLOGY...JT/DW
TIDES/COASTAL FLOODING...