discussion on 2023-11-18

000
FXUS61 KOKX 182337
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
637 PM EST Sat Nov 18 2023

.SYNOPSIS...
High pressure builds towards the region through Monday. The high
tracks across northern New England Monday night, and moves
offshore Tuesday. A warm front moves into the region late
Tuesday night followed by a cold front Wednesday. High pressure
builds in from the southwest Thursday and Friday. Low pressure
approaches along the coast Saturday.

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --Dew points have been running several degrees below forecast
values as direr air filters in to the region on a diminishing
northwest flow. Also updated other parameters for current
conditions.

Clouds will continue to clear out into the eve, with skc
overnight. NW winds will continue overnight. Although speeds
will not be excessive with about 20-25kt modeled around 2k ft,
it should be enough to keep from ideal radiational cooling.
Stuck with the warmer NBM as a result.-- End Changed Discussion --

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Some fair wx cu possible on Sun around 5k ft per model timeheights.
Strong subsidence aloft so it should flatten out. A well mixed WNW-W
flow, and mixing down h85 temps is very close to the NBM. Therefore,
the NBM was followed, which means expected highs in the lower 50s.

A little cirrus Sun night, but the main challenge is whether the
winds will be significant enough to keeps temps from bottoming out.
Models indicate lessening speeds aloft, but h85 speeds still around
15 kt by 12Z Mon. It may end up being only localized colder spots.
Too close to have high confidence attm in going colder than the NBM,
so stuck with it for this fcst cycle.

.LONG TERM /MONDAY THROUGH SATURDAY/...
The main feature of the long term period will be a low pressure
system that is expected to impact the region later Tuesday and
Tuesday night, into early Wednesday.

Otherwise, Monday will be dry with the center of high pressure
passing through update New York and across Northern New England, and
off shore during Tuesday. With nearly clear skies and diminishing
winds Monday night there is a chance that temperatures, especially
across outlying locations will be lower than forecast.

Tuesday an upper ridge will be moving off the east coast as a full
latitude upper trough moves through the upper midwest and Gulf
coast states. The upper trough will be progressive and move across
the eastern states Tuesday night into Wednesday morning.
Meanwhile, on surface low pressure will be weakening and passing to
the north Tuesday night while another low deepens along the Delmarva
and tracks to mainly to the south of the region. There is
uncertainty as to how far inland a warm front with the low will
track into the region, with much of the guidance indicating that
the warm front moves into the coastal plain before the low moves
east and a cold front follows. With strong isentropic lift along the
warm front and precipitable water increasing to around an inch
Tuesday night, periods of moderate to heavy rainfall will be
possible. While the system is progressive, an inch to two inches of
rainfall is possible.
There is little elevated CAPE and little to no instability, so
convection is not expected.

There is some uncertainty with the development of another low on
the cold front south of the region, with the NBM keeping the area
dry, and followed that guidance at this time. Wednesday night and
Thanksgiving are expected to be dry with temperatures slightly below
normal. There is a chance that an inverted trough, or low moves
along the coast and toward the region for next Saturday.

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --High pressure will be in control through the TAF period.

VFR.

NW winds remain 10-15kt with occasional gusts to 20kt possible
through 3Z. Winds decrease and back to the W overnight. WNW
winds 10-15kt on Sunday with gust around 20kt in the afternoon.

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

Gusts may be more occasional through 3Z. Start time of gusts
Sunday may be 1-2 hours earlier than forecast.

OUTLOOK FOR 00Z MONDAY THROUGH THURSDAY...

Sunday Night: VFR.

Monday: VFR.

Tuesday: VFR AM. Chance MVFR and rain late afternoon. SE gusts
around 20 kt in the afternoon.

Tuesday night: IFR and rain. SE gusts around 30kt possible. LLWS
possible toward the early Weds AM morning push with SE winds
40-50kt at 2kft.

Wednesday: IFR/MVFR with rain likely early. Bcmg VFR in the
afternoon with W-NW gusts around 20kt possible.

Thursday: VFR. NW gusts around 20kt possible.

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

.MARINE...
-- Changed Discussion --Gusts on the non ocean waters have diminished to below 25 kt,
although there may be an occasional gusts near 25 kt across the
south shore bays until 01Z. With gusts below 25 kt and
occasional, have cancelled the SCA on the non ocean waters.

A sca remains in effect thru Sun ngt on the ocean waters. Winds
diminish overnight, but remain gusty thru Sun. An uptick in
speeds Sun aftn/eve, but only the ocean is expected to hit 25kt
attm. The remaining waters will be close though, so changes to
the fcst are possible. Seas on the ocean aoa 5 ft thru Sun ngt.

SCA conditions will likely be on-going across the ocean waters
Monday, in a gusty northwest flow. Conditions are expected to be
improving through the day, falling below advisory by late Monday.
Then sub SCA conditions remain on the waters Monday night into
Tuesday morning.

Increasing southeast winds will allow ocean seas to build back up
to SCA levels by late Tuesday, and ocean gusts may also reach SCA
levels. There is some uncertainty as to how much mixing of higher
winds aloft there will be, however, gradient will be increasing.
Tuesday night SCA conditions develop across all the forecast waters
with the potential for gale gusts across the ocean waters and maybe
the eastern Long Island Sound late Tuesday night through most of the
day Wednesday. Conditions slowly improve on the ocean waters late
Wednesday into Wednesday night as low pressure moves to the east and
northeast.
However, SCA conditions are expected across the forecast waters
Wednesday night. Sub SCA conditions develop during Thursday in a
diminishing northwest flow as high pressure builds to the southwest
of the waters.-- End Changed Discussion --

.HYDROLOGY...
There are no hydrologic concerns through Tuesday. Moderate to heavy
rain is likely Tuesday night into early Wednesday morning, with
minor and nuisance flooding possible. There is the potential for 1
to 2 inches of rainfall, with locally higher amounts possible. Much
of the area is in a marginal risk for flash flooding.

.TIDES/COASTAL FLOODING...
-- Changed Discussion --While astronomical tides remain relatively low into the
beginning of next week, an increasing southeasterly flow Tuesday
into Tuesday night, ahead of a frontal system, will allow
forecast surge to increase. Local to widespread minor coastal
flooding is becoming more likely along the south shore back bays
during the high tide cycles late Tuesday night/early Wednesday
morning. Statements and/or advisories may be needed if the
possibility of coastal flooding continues to increase.-- End Changed Discussion --

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EST Monday for ANZ350-353-355.-- End Changed Discussion --

SYNOPSIS...JMC/MET
NEAR TERM...JMC/MET
SHORT TERM...JMC
LONG TERM...MET
AVIATION...MW
MARINE...JMC/MET
HYDROLOGY...JMC/MET
TIDES/COASTAL FLOODING...