251
FXUS61 KOKX 202057
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
357 PM EST Wed Nov 20 2024

.SYNOPSIS...
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Strengthening low pressure moves in from the south tonight and
meanders over the Tri-State area through Friday before shifting
northeast Friday night. The low will move towards the Canadian
Maritimes on Saturday and then tracks slowly northeast through
Monday. At the same time, weak high pressure builds in from the
west. A weak frontal system will then pass through the area
Monday night into Tuesday, followed by high pressure for the
middle of next week.
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&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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A warm front ahead of developing low pressure to our south
approaches. Lift and upward forcing increase with the front,
deepening low center, and strengthening low level jet. Most of the
rain tonight will fall after midnight and coincide with the axis of
deepest moisture shifting through as indicated by modeled PWATs.
Moderate to briefly heavy downpours are therefore anticipated at
times, and can`t even rule out a rumble of thunder across southern
zones as upward forcing near the developing low center interacts
with some CAPE. Lows near 50 for the coastal areas and mid to upper
40s inland. Winds pick up out of the east late with gusts up to 25
mph possible.
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&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
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Closed H5 low shifts in from the west Thursday and captures the
surface low Thursday night. This will cause the storm center to
linger over or close to the forecast area through Friday. The storm
then begins to shift NE Friday night. Rain continues through
Thursday, and at least for some areas east of the city, becomes less
steady Thursday night. Cold air wraps in from the west with the low
center continuing to deepen. Areas well NW of the city, particularly
the higher elevations, therefore see a wintry mix of rain and snow
as freezing heights fall in the range of 750-1250 feet. Snow
accumulation forecast here into Friday morning is tricky as thermal
profiles are marginal, and with the low center nearby, there could
be a somewhat sharp gradient in qpf as well as strong upward
frontogenetic forcing nearby. Heavier precip may overcome marginal
thermal profiles and end up in snow accumulations higher than
currently forecast. Elevations above 1000 feet may see 2-4 inches of
snow accumulation by the end of Friday morning, but this is not
enough to warrant an advisory as this would not be much coverage.
Breezy mainly near the coast with the chance of a lull in the winds
during the afternoon.

Models are in decent agreement that the center of the storm tracks
south through eastern PA during Friday before shifting east across
the forecast area Friday night. Periods of rain with the higher
chances generally near the low center. Thermal profiles still
support a wintry mix well NW of the city, but since the higher
chances of precip overall are during the daytime hours, any
additional snow accumulation would be very little. Breezy mainly by
the coast, but winds may be a little stronger than currently
forecast if the center of the storm doesn`t track over us. Went a
little colder than NBM for temperatures and dewpoints during the
short term.
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&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...

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* Gusty NW flow and near normal temperatures behind departing storm
  system this weekend.

* Weak frontal system to move through the area Monday night into
  Tuesday.

Deepening low pressure approaching the Canadian Maritimes on
Saturday will gradually lift northeast through the weekend into
early next week, while weak high pressure builds east from the Ohio
Valley. Except for a chance of showers Saturday, mainly in the
morning, it will be dry during this time with a strong NW flow.
Gusts will approach 30 mph each afternoon, with brief higher gusts
up to 40 mph possible. Leaned toward a cooler model consensus/MOS
forecast as compared to the NBM based on latest vertical temperature
profiles from some of the 12Z guidance. This will put highs just
below normal Saturday in the upper 40s to around 50. Winds stay up
Saturday night keeping temperatures about 5 degrees above normal.
Expect slightly warmer temperatures on Sunday.

A nearly zonal upper flow to start the week will send a fast moving
low NE across the Ohio Valley and Lower Great Lakes Monday, to the
north of the area on Tuesday. This will send a weak frontal system
through the area Monday night into Tuesday morning with a low chance
for rain. High pressure then builds in through midweek. Temperatures
Monday and Tuesday will be a few degrees above normal, but then cool
back down Tuesday night into Wednesday at or just below normal.
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&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
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High pressure gradually moveS east of the terminals through this
evening. A frontal system approaches tonight with low pressure
strengthening just south of Long Island into Thursday.

Mainly VFR through 0-2z, before conditions lower to prevailing MVFR
by 02-05z at city terminals, with RA arriving closer to 06z. IFR
should then quickly develop after 06z with moderate to heavy rain
possible through early Thursday morning, especially for NYC metro
and Lower Hudson Valley terminals. A rumble of thunder cannot be
ruled out. The moderate to heavy rain will shift east of the NYC
terminals around 12-13z. A lighter rain overall will persist through
the day Thursday, and into Thursday evening. Some local LIFR is
possible.

Light winds over the next several hours, before E winds increase
late this evening and start to become gusty towards midnight. Gusts
20-25 kt, with a few peak gusts at 30 kt are possible overnight into
early Thursday morning. Western terminals will see winds become more
N into Thursday morning.

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

Amendments likely for timing of lowering flight categories as well
as developing rain late this evening and overnight.

Amendments likely for winds late tonight into Thursday, especially
with magnitude and duration of gusts.

OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...

Thursday afternoon...IFR with possible local LIFR in rain, NE gusts
20-25kt. Wind direction likely becomes NW across NYC to Lower Hudson
Valley Terminals, otherwise ENE to Variable in direction.

Thursday Night...IFR to MVFR with periods of rain, possibly mixed
with wet snow well NW of NYC metro. SW gusts 15-25 kt.

Friday...Mainly MVFR with rain possible. Wet snow may mix in well NW
of the NYC metro. S-SW gusts 15-20kt possible.

Saturday...MVFR possibly becoming VFR late. WNW winds gusting 20-
30kt.

Sunday...VFR. W-NW winds gusting to 20-30kt.

Monday...VFR. Light winds.

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

.MARINE...
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All waters remain under a small craft advisory tonight through
Thursday night. There may be a short period Thursday morning on the
ocean waters where there may be a few gale force gusts. A better
chance of gales for the ocean during Thursday night, however this
will depend on the track of the storm, and with the storm center so
close, not confident enough to upgrade to a Gale Warning. Will let
the night shift get a look at new guidance to see if confidence
increases for gales during Thursday night. Otherwise, SCA will
likely need to be extended into Friday, mainly on the ocean, as seas
remain elevated through the day.

A strong NW flow behind deepening low pressure lifting NE across the
Canadian Maritimes this weekend will at least produce SCA seas and
winds across the waters, with the potential for Gale force gusts.
The best chance for gales at this time will be across the ocean from
Saturday afternoon through Sunday afternoon. Thereafter, high
pressure builds in from the west with decreasing winds and seas
Sunday night into Monday.
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&&

.FIRE WEATHER...
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A Special Weather Statement continues through 6PM for southern
CT based on collab with CT fire partners. A substantial wetting
rainfall is then expected tonight night through Friday which
should help mitigate short term concerns for fire danger, but
would not be enough to lift us from long-term drought.
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&&

.HYDROLOGY...
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Overall storm total rainfall tonight through Friday night is 2.5-3
inches west of the Hudson, ranging closer to 1.5-2.5 inches to the
east. Most of this, along with any potential impacts, is expected to
occur late tonight into Thursday morning. There could be minor
flooding associated with clogged drains, otherwise no hydrologic
impacts are expected given the recent dry weather and progressive
nature of any heavier rainfall.

No hydrologic impacts are expected this weekend through the middle
of next week.
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&&

.TIDES/COASTAL FLOODING...
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Astronomical tides will continue to fall through the end of the
week. However, an intensifying low south of Long Island late tonight
into Thursday will bring a surge of 2 to 3 ft, especially across the
coasts of Long Island and Southern CT. The exact location/track of
the low will be important to the magnitude and duration of the surge
along with it coinciding with the timing of high tide.

Confidence is highest for minor coastal flooding benchmarks to be
exceeded across the south shore back bays of western LI, Great South
Bay, and eastern LI Bays as well as along much of the north shore.
Minor coastal flooding also looks widespread across southern
Fairfield and southern Westchester. Coastal Flood Advisories remain
in effect for these areas for the late Thursday morning into
Thursday afternoon high tide. For N Nassau and N Queens as well as
the southeastern coast of CT, any minor flooding looks localized
which is being addressed with a statement. The surge may peak for
the NY harbor earlier than high tide with the flow becoming westerly
on the backside of the low, which should prevent any coastal
flooding.

This is currently being reevaluated with an update expected around 6
pm this evening.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from 1 PM to 5 PM EST Thursday for
     CTZ009.
NY...Coastal Flood Advisory from 1 PM to 5 PM EST Thursday for
     NYZ071.
     Coastal Flood Advisory from 11 AM to 5 PM EST Thursday for
     NYZ078>081.
     Coastal Flood Advisory from 10 AM to 2 PM EST Thursday for
     NYZ179.
NJ...None.
MARINE...Small Craft Advisory from 11 PM this evening to 7 AM EST
     Friday for ANZ331-332-335-338-340-345-350-353-355.

&&

$$

SYNOPSIS...JC/DW
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...DW
AVIATION...JE
MARINE...JC/DW
FIRE WEATHER...JC
HYDROLOGY...JC/DW
TIDES/COASTAL FLOODING...