discussion on 2023-11-25

000
FXUS61 KOKX 252338
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
638 PM EST Sat Nov 25 2023

.SYNOPSIS...
High pressure over the region tonight will slowly move off the
New England coast on Sunday. Low pressure then impacts the area
Sunday night into early Monday morning. High pressure slowly
builds in Monday afternoon through Wednesday followed by low
pressure passing to the north of the area Wednesday night. High
pressure then returns for late in the week followed by low
pressure approaching from the southwest late Friday.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --The forecast is mainly on track tonight. Winds have gone calm
across eastern Long Island and a few other spots across southern
CT, allowing for some radiative cooling to commence.
KFOK/KHWV/KJPX have all dropped between 3 and 5 degrees over the
past hour. Given this and current dewpoints in the low to mid
teens, have lowered temperatures, and min temperatures, a few
degrees into the lower 20s for central and eastern Long Island,
and southern CT. These trends will have to be monitored over the
next few hours, with incoming cloud cover still out in western
PA. Previous discussion follows.

Dry and cold conditions will continue tonight with high
pressure over the region. The main challenge will be with
temperatures and the amount of cloud cover. The first half of
the night will likely be mostly clear. However, mid and high
clouds increase well ahead of an amplifying upper trough over
the Plains.

Temperatures will fall quickly this evening under mostly clear
skies and light winds before leveling off or only slowly
falling early Monday morning. Lows look to be similar to Friday
night/early Saturday for most locations with readings in the
lower 20s inland and middle and upper 20s elsewhere. Since cold
advection has ended, NYC likely stays just above freezing. If
clouds are quicker to move in overnight, lows may end up a few
degrees warmer. If the clouds are slower to move in, then lows
could be a few degrees colder outside of the NYC metro.-- End Changed Discussion --

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
High pressure slowly shifts offshore on Sunday as heights
aloft gradually fall in response to the aforementioned
amplifying upper trough. The return flow around the surface high
will help bring an increase in moisture in the low levels
through the day. Moisture profiles indicate saturation occurring
around 3-5 ft which will result in a stratocu deck expanding
from south to north through the day. An inverted trough off the
Carolinas will also develop a low pressure late in the day. Have
continued to keep the forecast dry for the daytime hours on
Sunday. Temperatures will moderate into the 40s for highs, a few
degrees below normal for this time of year.

The upper trough will interact with the developing low near
the North Carolina coast Sunday evening. The trough will help
lift this low towards the area overnight. The model guidance is
in fairly good agreement that the low will near the Long Island
coast after 06z and then track towards Cape Cod by 12z Monday.
This fast movement is supported by the progressive synoptic
pattern in place. The system will bring a quick shot of rain
beginning late Sunday evening and continuing into early Monday
morning. The rain could become moderate at times, especially
across Long Island and southern Connecticut, where slightly
stronger thermal forcing sets up closer to the low center. The
rain will end quickly from west to east from early Monday
morning as the low pulls away to the northeast. Confidence is
fairly high that the rain will end by the beginning of the
morning rush hour from the NYC metro on north and west. The rain
should end by around 12z across eastern Long Island and
southeast Connecticut. Forecast amounts range from around a half
inch or less along the Hudson River corridor to three quarters
to an inch eastern Long Island and southeast Connecticut.

While winds may briefly become gusty for eastern portions of
the area late Sunday night, stronger winds are more likely on
Monday behind the low. The pressure gradient tightens on Monday
due to the low continuing to deepen as it tracks into SE Canada
by late day. This will bring increasing winds into Monday
afternoon with sustained winds 15-20 mph gusting 25-30 mph. A
few gusts up to 35 mph are possible near the coast in the
afternoon. Temperatures may peak in the upper 40s to low 50s
early in the day and then fall in the afternoon as colder air
begins advecting into the area.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Global ensemble guidance is in agreement with the overall pattern
evolution with an anomalously deep low centered over eastern Canada
to start the period with a more zonal pattern taking shape by week`s
end. The NBM with some adjustments to winds/gusts was predominately
used for this forecast update.

The highlights for the long term are:

* Below normal temperatures for much of the period with Tuesday and
  Wednesday the coldest days. A gradual warmup ensues thereafter,
  into next weekend.

* Dry and windy conditions Monday night through Wednesday, with the
  next chance of precipitation late Friday into Saturday.

A strong pressure gradient remains intact as a surface low continues
to deepen as it heads northeast of the region on Tuesday. Behind
this system, cold air advection and thicknesses in the low 500s dam
will result in a blustery, but dry, period. NBM winds have been
adjusted up toward the 90th percentile from Monday night into
Tuesday afternoon, as model soundings indicate deep mixing up to 650-
700mb. In addition, an upward trend in NBM winds/gusts was noted
over the past several cycles with 30-35mph gusts looking more and
more likely late Monday and again on Tuesday afternoon. Given the
combination of cold temperatures (low to mid 20s) and elevated
winds, wind chills in the upper teens and lower 20s are possible
Monday night and Tuesday night, should the forecast hold. Highs on
Tuesday and Wednesday will struggle to get into the 40s for the
urban and coastal areas, and into the upper 30s across the interior.

The upper flow deamplifies by late Wednesday into Thursday with a
return to southerly flow as sfc high pressure slides offshore. This
will allow temperatures to moderate a bit, Thursday and Friday, into
the mid and upper 40s, as dry conditions continue. By late Friday,
guidance is advertising a low pressure approaching the area from the
southwest, as a southern stream mid/upper shortwave lifts out of the
Southern Plains. For now, given the large uncertainty this far out,
have maintained the NBM chance PoPs starting late Friday.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --High pressure builds overhead into this evening, moving
offshore late tonight. Low pressure impacts the area Sunday
night.

VFR through Sunday morning and much of the afternoon. MVFR
conditions move in Sunday evening.

Light and variable winds expected overnight, with terminals
outside the metro terminal becoming calm. A light south to southeasterly
flow develops Sunday.

Lowering cigs late Sun AM into the afternoon ahead of the next
incoming storm system that brings rain to the terminals Sunday
evening. MVFR cigs develop by the afternoon or early evening.

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

No unscheduled amendments expected.

OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...

Sun PM: Rain showers develop in the evening, with MVFR or lower
conds.

Mon: Improvement to VFR in the morning. WNW wind 15-20kt, G25-30kt.

Tue: VFR. W wind 15-20kt, G25-35kt.

Wed: VFR. SW wind 10-15kt, G20kt.

Thu: VFR. W wind 10-15kt, G20kt.

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

&&

.MARINE...
Tranquil conditions will persist on the waters through Sunday as a
weak pressure gradient remains in place. Low pressure then develops
along the Carolina coast late Sunday and quickly tracks over the
waters Sunday night into early Monday. This will bring an increase
in winds with the best chance for SCA conditions on the ocean east
of Moriches Inlet. Seas may also build to around 5 ft east of
Moriches Inlet late Sunday night. Have held off on the issuance of
an SCA for now. SCA conditions are more likely on all waters on
Monday as the low pulls away to the northeast. Latest trends in the
model guidance indicate lower potential for gales on Monday, but
will still mention in the HWO for now on the ocean. The increasing
winds will result in 6 to 8 ft waves on the ocean waters and 4 to 5
ft waves across the central and eastern Sound.

SCA conditions continue Monday night into Tuesday evening on all
waters. There is a chance of a short period of gales on the ocean
waters Tuesday afternoon.

Conditions will be improving slowly from the west as high pressure
builds into the area by Wednesday morning. SCA conditions will
remain on the ocean waters, mainly east of Fire Island Inlet.

Marginal SCA conditions then remain on the ocean waters Wednesday
night into Thursday as the pressure gradient remains rather strong
as a low passes to the north.

&&

.HYDROLOGY...
Dry conditions will continue through Sunday afternoon. There are no
hydrologic concerns from around one half to one inch of rain Sunday
night into early monday morning.

There are no hydrologic concerns Monday afternoon through
Friday.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides will be increasing into early next week due
to a full moon early Monday morning. Water levels may just touch
minor benchmarks during the Sunday morning high tide for a few
vulnerable locations across the south shore back bays of Nassau
and along coastal Fairfield. Have held off on any statements at
this time. Minor coastal flooding looks more likely for the
south shore back bays of Nassau and Queens, Western Long Island
Sound across coastal Westchester and coastal Fairfield with the
Monday morning high tide. A quickly developing low pressure may
help bring enough of a surge (only around 0.50-0.75 ft needed)
to reach minor benchmarks. Water levels may also come close to
minor benchmarks across the Lower NY Harbor and the bays along
the SE coast of Long Island.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...DBR/DS
NEAR TERM...DBR/DS
SHORT TERM...DS
LONG TERM...DBR
AVIATION...JP/DR
MARINE...DBR/DS
HYDROLOGY...DBR/DS
TIDES/COASTAL FLOODING...