discussion on 2023-11-14

000
FXUS61 KOKX 150341
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1041 PM EST Tue Nov 14 2023

.SYNOPSIS...
High pressure builds in from the west through morning, then
offshore by afternoon. Another area of high pressure establishes
itself across the region late Wednesday night into Thursday
before moving offshore at the end of the week. A cold front and
coastal storm affect the area Friday night through Saturday.
High pressure builds in for the second half of the weekend into
the beginning of next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
-- Changed Discussion --High pressure will continue to build in from the west through
the night. The combination of clear skies and diminishing north
winds will allow for good radiational cooling.

The forecast lows range from the lower 20s across parts of the
interior and rural sections of Eastern Long Island in the Pine
Barrens to upper 30s along the parts of the immediate coast as
well as much of NYC. Compared to Monday night, tonight is
expected to have quite a bit more frost formation. Much of the
forecast region is forecast to have frost develop.

In areas where growing season is still active (Hudson NJ, Southern
Nassau NY and NYC), patchy front is possible, but not enough to
warrant an advisory. Lows in these areas will range from the
upper 30s to near 40.-- End Changed Discussion --

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
The strong high pressure area will eventually move offshore on
Wednesday.

Subsidence from high pressure aloft will keep skies mostly
clear on Wednesday. Light winds Wednesday morning will
eventually increase and become more southwesterly in the
afternoon. With limited vertical mixing, forecast high
temperatures will be similar to those of the previous day,
ranging from the upper 40s to lower 50s but with some mid 50s
for parts of NYC and Northeast NJ. Some increase in clouds is
expected for the latter half of the afternoon.

For Wednesday night, warm air advection weakens. Mid level flow will
be quasi-zonal without much change in 500mb height. High pressure at
the surface moves farther offshore. Low level SW flow remains.
Surface flow remains up and more clouds are expected in
coverage so radiational cooling will be less especially along
the coast. A frontal system will be passing well north of the
region. Lows will be relatively warmer than the previous night
as a result. A blend of MAV and MET guidance was used for
forecast lows, ranging from the around 30 for the interior and
rural sections of Eastern Long Island within the Pine Barrens to
mid 40s for parts of NYC.

For Thursday, nearly zonal flow remains with some slight ridging in
the mid levels. At the surface, high pressure will continue moving
offshore. The increased ridging is forecast to make for a mostly
sunny day. Some more low level warm air advection is forecast
and while vertical mixing will be relatively similar to the
previous day, the temperatures will be warmer at the top of the
mixed layer. So, mixing adiabatically down is forecast to
result in temperatures substantially warmer than the previous
day. A blend of MAV, MET and NBM was used for forecast high
temperatures, ranging from the mid 50s to lower 60s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
A mid/upper-level ridge overhead Thursday night exits to the
east and loses influence on Friday. Clear skies will be the norm
across the area Thursday night with light southwest winds. Some
radiational cooling will be possible, but Thursday night will
be warmer than Wednesday night due to increasing clouds and
gradually strengthening southwest winds in the early morning on
Friday.

A sector of the southern jet stream is expected to phase with the
northern jet stream, leading to a stronger jet streak in the region.
This will allow a weak coastal system off of the south Atlantic
coast to rapidly strengthen as it tracks northward along the
Atlantic coast. The placement of this jet streak and the coastal low
vary among the available 12Z guidance, but most solutions now point
towards the coastal system tracking farther out to sea which means
POPs have been lowered in this forecast package to the prior
morning forecast package. It appears the 12Z GFS is the outlier,
still leaving the system with a track closer to the coast. In
that scenario, POPs may need to be raised. POPs are 40-50% for
much of the area early on Saturday with the eastern end of Long
Island and SE CT seeing increased chances of 60-70% due to their
proximity to the coastal low.

The strengthening coastal low to the south will also increase SW/S
winds from a stronger pressure gradient with breezy conditions
expected to develop on Friday, with the strongest winds in the
eastern part of the forecast area. The stronger winds will also
help mix down warm temperatures aloft, likely leading to Friday
afternoon being around 10 degrees above average in the
low/mid-60s.

A cold front will follow the quickly exiting coastal low with only
light precip expected along the front Saturday afternoon/evening. At
the same time an upper/mid-level trough will begin to rapidly
strengthen. Breezy NW winds following the frontal passage Saturday
night into Sunday will allow the area to quickly dry and cool with
clearing skies.

Skies remain clear with a strong trough aloft with surface high
pressure building at the surface on Sunday. A northwest wind will
reinforce colder air in the region. Sunday night into early Monday
some mid-level positive vorticity advection and increasing amounts of
700mb relative humidities along the periphery of the upper-level
trough could lead to some cloud development. This may limit low
temperatures Monday morning, but still expecting lows in the
upper-20s to mid-30s. Have blended in some 75th percentile NBM
to hint towards slightly warmer overnight lows due to partly
cloudy skies somewhat limiting radiational cooling.

Clear skies return on Monday with surface high pressure remaining in
place. The upper-level trough is expected to exit eastward Monday
night into Tuesday as a ridge inches closer from the west.

&&

.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --High pressure builds in from the west overnight into Wednesday
morning before moving offshore late morning/early afternoon.

VFR. N winds will continue to diminish through the night, becoming
light and variable in the morning. Winds will then become S/SW
at 7 to 10 kt from late morning into early afternoon.

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

No unscheduled amendments expected.

OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...

Wednesday Night through Thursday: VFR.

Friday: VFR, lowering to MVFR or lower in showers late day into the
evening. S G15-20kt.

Saturday: Chance of MVFR or lower in showers, showers ending with
conditions improving late in the day. NW G15-25kt.

Sunday: VFR. W G20-25kt.

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

&&

.MARINE...
SCA has been dropped across all waters as northerly winds
gradually diminish through the night with high pressure building
in from the west.

As the high moves offshore Wednesday afternoon/night and a
frontal system passes well to the north, the pressure gradient
increases. Gusts up to 20 kt are expected toward evening with
gusts up to 25 kt possible on the ocean at night. The gusts look
to be more occasional than frequent at this time. A SCA is
possible.

For Thursday through Friday, conditions on the waters are
forecast to remain below SCA thresholds.

Next potential for SCA conditions is Friday Night thru next
weekend with increasing S/SE winds and building waves ahead of
approaching cold front and then NE/offshore winds likely with
coastal low development. 25-28 kt gusts are possible on ocean
waters, primarily limited to Saturday night. Waves on Saturday
could build to 5 to 12 ft on the ocean waters, and up to 9 ft
are possible at the sound entrance. SCA conditions are expected
through early Monday afternoon with seas at or above 5ft,
dropping below 5 feet Monday night.

&&

.HYDROLOGY...
No hydrologic impacts expected through the beginning of next
week.

&&

.TIDES/COASTAL FLOODING...
With high astronomical levels due to the recent new moon, a few
locations along South Shore Bays, mainly in Southern Nassau NY
are expected to approach or just touch the minor coastal flood
benchmarks during their high tide Wednesday morning. Roughly
around 1.5 ft of surge is needed for minor coastal flooding on
average. There is a coastal flood statement in effect from 7AM
to 10AM Wednesday morning for Southern Nassau NY. Other
locations along the coastlines are expected to remain below
minor coastal flood benchmarks.

&&

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

&&

$$

UPDATE...DW