388
FXUS61 KOKX 250923
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
423 AM EST Mon Nov 25 2024

.SYNOPSIS...
Weak high pressure will pass through the area today, giving way
to an area of low pressure over the Ohio Valley states. The low
will pass well to the northwest tonight into Tuesday, sending a
warm front through the area Tuesday morning, followed by a cold
frontal passage in the afternoon. High pressure briefly returns
for Wednesday. Low pressure will then pass nearby on Thanksgiving
and exit to the northeast Friday. High pressure gradually builds
in from the southwest next weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Ridging both aloft and at the surface moves through the area
today with a much lighter westerly flow. At the same time, an
amplifying upper trough over the Upper Midwest approaches the
Great Lakes, sending surface low pressure across the Midwest.
The latter of which will become a player late tonight into
Monday.

Clouds increase toward evening across western portions of the
area, thus looking mainly at a mostly sunny day with highs
slightly above normal.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
A fast moving, negatively tilting upper trough will lift across
the Great Lakes and Ohio Valley states tonight, and then across
the Northeast on Tuesday. The main surface low passes well to
the northwest, sending a warm front across the area Tuesday
morning, followed by a cold frontal passage in the afternoon.
Expect a period of rain, moderate at times, moving across the
area Tuesday morning, exiting far eastern LI/SE CT in the
afternoon. The system will be progressive only resulting in 0.20
to 0.40" of rainfall across the area, highest across the
interior. Models are in good agreement with the overall trend
the last couple of days being slower.

While much of the rain falls Tuesday, many of the CAMs are
pointing to spotty light rain/sprinkles overnight in the warm
advection. However, plenty of dry air will be in place and it
will take some time to moisten. Lows are forecast to be in the
upper 30s inland, to the 40s along the coast. This is about 5 to
8 degrees above normal.

Conditions dry out Tuesday afternoon with highs in the mid 50s
to around 60. Southerly winds in the morning may gust up to 20
mph along the coast, followed by gusty west winds everywhere
in the afternoon behind the cold front. Some of the gustiness
will linger along the coast Tuesday night. High pressure builds
in from the west Tuesday night into Wednesday with temperatures
returning to normal.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...

Forecast Summary:

* A weather system will bring a good chance for rain along with
  a small chance of snow in the interior Thanksgiving morning
  into Thanksgiving night.

* Cold air filters in Friday into the weekend for some of the
  coldest temperatures so far this season. Breezy weather is
  possible during this time.

Detailed Forecast Discussion:

Wednesday night a low pressure system will be located somewhere to
our west and south. This system will then pass through the area or
just to the south of the area on Thanksgiving Day, deepening as it
moves off the New England coast Thanksgiving night into Friday. A
deep upper-level trough will follow the exiting low and continue to
amplify across the eastern CONUS into Monday with surface high
pressure building in from the southwest Friday into the beginning of
next week.

A lot of uncertainty surrounds the anticipated Thanksgiving system
and the latest 00Z guidance has led to some expected changes in the
forecast. There are 3 main characteristics of the anticipated low-
pressure system that will determine what we see on Thanksgiving:
Strength of the low, timing of the low, and location of the low.
Let`s take a look at each of these.

Timing of the low. After assessing the latest 00Z guidance,
including 00Z ECMWF, GFS, ICON, GDPS, their ensembles, and even more
obscure global models such as the UKMO, ACCESS-G, and ARPEGE in order
to ascertain some consensus, the most consistent finding was the
timing of the system. The low is expected to approach and pass the
area Thanksgiving morning and exit northeast Thanksgiving night.
During this timeframe, precipitation is expected, with most models
starting precip early Thanksgiving morning and quickly cutting off
precip late Thanksgiving night as the low accelerates northeast of
the area.

Location of the low. Unfortunately, models still vary widely on
placement of the Thanksgiving system. It appears the 00Z ECMWF has
the most interior and northerly solution which develops the low to
our WSW and then brings it over the CWA, exiting to the northeast.
The 00Z GFS has the most southerly track with the low never crossing
through the area, but instead, grazing the CWA as it takes a more
southerly track before turning up the coast exiting to our
northeast. All other global guidance appears to lie somewhere in the
middle, with most solutions bringing the low right over the CWA or
just a smidge to our south. Given this, confidence is slightly
higher in the low tracking over the area or very close to shore to
our south. This would likely lead to a slightly warmer scenario,
providing mostly rain with a few chances for snow in the far
interior. Given the prior talked about timing, the most likely
window for snow will occur with the low`s exit, which will mainly
be limited to the interior.

Strength of the low. Models vary all over the place in terms of the
strength of the low. All models have the low deepening, but some
have it deepening as it passes the CWA while others deepen the low
only after it exits to the northeast. There is still too much
variability in the guidance to say for sure which will happen, but
more models appear to show a weaker low that deepens upon its exit.
This scenario would lead to less chances for heavier precip, with
mainly passing rain showers. With a weaker low, winds would likely
only pick up as it deepens on its exit due to the increasing
pressure gradient. A weaker low would also mean less cold air
advecting into the system until it exit, so have gone with mainly
rain for this system Thanksgiving into Thanksgiving night. This is
certainly subject to change, however, due to the low confidence in
the forecast.

For the Thanksgiving, with with a blended model solution (NBM) which
kept things just warm enough to lead to a mainly rain event, which
lined up with expected forecast, but again, this is very subject to
change.

As the low deepens to our northeast on Friday, NW winds are expected
to pick up and may remain breezy through Monday. This will also
allow for plenty of colder air to advect in with a cold weekend and
a cold start to next week. This will be aided by a deep upper-level
trough moving in on Friday and continue to amplify across the
eastern CONUS into Monday. High pressure at the surface building in
from the southwest will lead to decreased cloud cover into the
weekend. Some models hint at a few rain/snow showers this weekend
into the start of next week, but have left our of the forecast for
now due to high uncertainty and lack of major sources of lift at the
surface in dry air mass and due to cold air advection.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
High pressure builds in today. A quick moving frontal system
approaches the terminals late tonight and passes through on Tuesday.

VFR.

A light, 10kt or less, WNW flow continues today. Light and variable
winds possible tonight before increasing out of the S early Tuesday
morning.

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

No unscheduled amendments expected.

OUTLOOK FOR 09Z TUESDAY THROUGH FRIDAY...

Tonight: VFR. Slight chance of showers late at night.

Tuesday: Showers with MVFR, periods of IFR possible. Showers ending
late in the afternoon into the evening, becoming VFR. SW winds
gusting 20-25kt along the coast.

Wednesday: VFR.

Thursday: MVFR/IFR with a chance of rain. Low chance for snow
showers at KSWF on Thursday night.

Friday: VFR. NW/W wind gusting 20-25kt.

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

&&

.MARINE...
SCA conditions across the ocean will likely come to an end the
next hour or two as high pressure builds in from the west. Sub-
SCA conditions persist through tonight. A frontal system will
then move across the area Tuesday with SCA conditions possible
on the ocean waters in the morning in a SW flow, with a better
chance in the afternoon and night in the westerly flow behind a
cold front. The non-ocean waters will be more marginal for wind
gusts, but a good possibility. High pressure then builds in for
Wednesday with diminishing wind and seas.

Conditions are expected to be below SCA levels Wednesday night
into Thanksgiving. Following a deepening departing low with
building high pressure to the southwest, SCA conditions are
expected to develop Thanksgiving night and may persist into the
weekend.

&&

.HYDROLOGY...
No hydrologic impacts are expected through the weekend.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EST early this morning for
     ANZ350-353-355.

&&

$$

SYNOPSIS...BR/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...BR
AVIATION...BR
MARINE...BR/DW
HYDROLOGY...BR/DW