000
FXUS61 KOKX 210214
AFDOKX
Area Forecast Discussion
National Weather Service New York NY
914 PM EST Mon Nov 20 2023
.SYNOPSIS...
-- Changed Discussion --
High pressure builds over the area tonight and then moves offshore
on Tuesday. Low pressure approaches in the afternoon and then
moves through the region Tuesday night into early Wednesday.
Low pressure slowly departs to the east Wednesday night through
Thanksgiving. High pressure then builds in and likely remains in
control through at least the first half of the weekend. A low
pressure system may impact the area Sunday into Monday.-- End Changed Discussion --
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
Forecast largely on track into the overnight. High clouds will
continue moving overhead through much of the night, although
there may be a period early Tuesday morning where the high
clouds briefly thin out.
Ridging aloft and surface high pressure remain in place tonight
The high clouds will dampen the effects of radiational cooling,
but not totally negate its effects since there are no low level
clouds expected tonight with light winds. Should still see lows
in the low/mid-20s for northern interior zones and the LI Pine
Barrens. Lows in the mid-30s for the NYC metro. A Freeze Warning
remains in effect from midnight to 8 am for the Bronx, Staten
Island, Hudson County, and Southern Nassau County with
temperatures in those locations falling to around 32 degrees.
The growing season here officially ends November 21.-- End Changed Discussion --
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
Low pressure tracks NE into the eastern Great Lakes Region on
Tuesday. Energy then gets transferred to a secondary low, with its
center passing through or very close to the forecast area early
Wednesday morning. The low will be east of us on Wednesday afternoon
with high pressure building in behind it.
Rain chances begin west to east late Tuesday afternoon to evening
before becoming likely mid/late evening into the night. There is a
chance for a brief mix of wet snow and rain at the onset across
northern Putnam and Orange counties with no snow accumulation. A low
level jet and strong isentropic lift right ahead of the approaching
secondary low will provide plenty of lift along with divergence in
the upper levels as the left exit region of a jet streak shifts
through during the overnight hours. These ingredients will combine
for periods of moderate to, at times, potentially heavy rainfall
after midnight. The stronger signal for this is generally over the
southern and eastern zones. The heaviest rainfall will probably be
over by sunrise Wednesday west of CT and LI, with the heavy rainfall
potential exiting east of eastern CT and eastern LI by mid-morning.
See the hydrology section below for additional information and
potential impacts. Another area of low pressure develops off of the
Carolina/Virginia coast, which keeps cyclonic flow over the ocean
through the period on Wednesday. It is possible some light isolated
showers or drizzle could be seen out of this Wednesday afternoon to
early evening only for far eastern Long Island and far eastern SE
Connecticut. Wednesday afternoon should be dry for everyone else.
One other aspect of this storm system will be winds, particularly
late Tuesday night/early Wednesday morning ahead of the secondary
low passage. 925mb winds for coastal areas during this time are
progged at 45-55kt. With a relatively weak low level inversion in
place, estimating 60-70% of this can mix down to the surface. Some
gusts in the 40-50mph range would therefore be possible. Not enough
confidence in a widespread enough event for a wind advisory in any
of the forecast zones, but do have far eastern areas in the Long
Island Forks reaching gusts of 45 mph. Peak wind gusts for coastal
sections are otherwise more likely to fall in the range of 30-40 mph.
Winds will quickly weaken as the center of low pressure moves
directly overhead Wednesday afternoon, reducing the pressure
gradient.
Highs Tuesday will be in the mid-40s for northern inland zones,
while southern coastal zones on Long Island, NYC, and NE NJ will be
in the low-50s. The warmer air here is thanks to increased southerly
flow.
Wednesday will be notably warmer with highs in the upper-50s to
lower-60s for southern zones and in the mid/low-50s for northern
zones. Strong warm air advection takes place from strong southerly
flow aloft with 850 mb temperatures around 6-8C (which is also
6-8C above average). Less cloud cover and rain will also help
things warm up some more.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
At the start of Wednesday night, low pressure will be exiting to the
east along with any associated rain. The forecast only includes a
slight chance of rain for New London County and far eastern Suffolk
County. The pressure gradient most of Wednesday night will actually
be relatively weak and expecting a lull period for winds. Aloft, a
mid-level shortwave trough will be passing to our south and an
associated surface low will be deepening as it passes to our south
and east early Thursday. This will strengthen the pressure gradient
over the area and lead to gusty conditions.
The low will gradually depart the area, with high pressure building
in thereafter. The high will likely remain in control through at
least the first half of the weekend with zonal flow aloft. The 12z
global guidance is in decent agreement with high pressure winning
out on Saturday. With previous wetter solutions likely impacting the
latest NBM PoP output, went lower with PoPs and expect this trend to
continue.
Sunday through Monday the guidance spread really increases. Stuck
close to NBM during this period because of low confidence. There is
potential for a low pressure system to impact the area, but
strength, timing and location are all in question.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
High pressure builds to the north of the area tonight and then
off the New England coast Tuesday. Low pressure will approach
from the southwest Tuesday afternoon, moving across the area
Tuesday night into Wednesday morning.
VFR conditions are forecast through Tuesday morning with MVFR
conditions developing Tuesday afternoon for NYC and Lower Hudson
Valley terminals (21z), and early evening for Long Island and
southern Connecticut terminals (22-23z). Light rain will begin
to develop late in the afternoon and evening and then become
moderate at night. Conditions will continue to deteriorate with
IFR likely after 02-03z Wednesday.
N-NNE winds under 10 kt overnight. NE winds gradually increase
Tuesday morning, becoming E-ESE in the afternoon. Winds will be
10-15 kt with gusts 15-20kt, especially at coastal terminals
before sunset. ESE winds will continue to increase Tuesday
night, becoming 15-20 kt with gusts 25-35 kt, strongest at
coastal terminals.
LLWS is possible for NYC and coastal terminals with potential
of 45-50 kt winds at 2kft after 03z Wednesday.
...NY Metro(KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
No unscheduled amendments expected tonight into Tuesday morning.
Timing of lowering flight categories Tuesday afternoon and
evening may be off by 1-3 hours.
Onset time of rain may be delayed 1-3 hours from forecast
Tuesday afternoon/evening.
Start time of wind gusts may be off by 1-2 hours Tuesday
afternoon.
OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...
Tue night: IFR with rain. SE winds 10-20 kt with Gusts 25 to 35
kt. Winds and gusts strongest near the coast. A few higher
gusts possible, especially at KGON. LLWS possible for coastal
terminals.
Wed: IFR early with lingering rain, especially east. Rain
tapers off late morning into afternoon with eventual improvement
to VFR late. SW-W winds 10-15 kt with gusts near 20-25 kt AM.
NW winds 10-15 kt with gusts 15-20 kt PM. LLWS possible at KGON
early.
Thu: VFR with NW to W winds 10-15 kt with gusts 20-25kt.
Fri-Sat: VFR.
Detailed information, including hourly TAF wind component forecasts,
can be found at: https:/www.weather.gov/zny/n90-- End Changed Discussion --
&&
.MARINE...
Sub SCA conditions prevail tonight. With waves on the ocean
increasing to about 5 ft early Tuesday morning, decided to issue
a Small Craft Advisory ahead of the Gale Watch. Low pressure
will then bring increasing winds and seas late in the day into
Tuesday night. A Gale Watch is in effect for all waters Tuesday
night. A gusty NW flow follows in the storm`s wake on Wednesday
with advisory level conditions possible on most waters.
There will be a lull period for winds Wednesday night as the
pressure gradient briefly decreases with low pressure passing to the
east. However, waves will remain elevated. by Thursday morning the
pressure gradient increases again and SCA wind gusts return likely
to all waters. Thereafter, winds and waves remain below SCA
criteria. There is potential for elevated winds and waves Sunday
into early next with with a potential low pressure system.
&&
.HYDROLOGY...
No hydrologic impacts are expected through Tuesday afternoon.
Total rainfall from late Tuesday afternoon through Wednesday morning
is expected to range from 1 to 2 inches. The highest amounts are
more likely to occur over NE NJ, NYC, and LI. Given these rain
amounts with antecedent dry conditions and flash flood guidance,
only minor/nuisance flooding is anticipated. The heaviest rainfall
is anticipated after midnight Tuesday night with the threat of heavy
downpours over for most spots by the start of the Wednesday morning
commute.
There are no hydrologic concerns Wednesday night through early next
week.
&&
.TIDES/COASTAL FLOODING...
An approaching storm system Tuesday into Tuesday night will
produce SE gale force gusts along the coastline, which will
produce a storm surge that could potentially raise waters levels
2 to 3 ft. There is some uncertainty with the timing of the max
winds/surge and how closely it will coincide with the time of
high tide. At this time, this looks to be a widespread minor
coastal flood event for the Wednesday morning high tide cycle,
with the most vulnerable areas being the south shore back bays
of western LI and the coastline of SW Connecticut. In addition,
heavy rainfall and wave action along the Connecticut coast could
enhance the flood threat. Localized moderate coastal flooding
is a possibility, especially across southern Nassau.
This is likely to be a one-high tide cycle event, but a lingering
SE swell could pose a localized minor coastal flood threat across
the south shore back bays of LI Wednesday afternoon/evening.
This is only being shown in the PETSS guidance (GEFS)at this
time. Westerly winds behind the system will aid in lowering
water levels.
Along the oceanfront, surf could build as high as 10 ft, resulting
in beach flooding and localized dune erosion.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None.
NY...Freeze Warning until 8 AM EST Tuesday for NYZ073-074-179.
NJ...Freeze Warning until 8 AM EST Tuesday for NJZ006.
MARINE...Gale Watch from late Tuesday night through Wednesday afternoon
for ANZ331-332-340.
Gale Watch from Tuesday evening through Wednesday morning for
ANZ335-338-345.
Small Craft Advisory from 6 AM to 6 PM EST Tuesday for ANZ350-
353-355.
Gale Watch from Tuesday evening through Wednesday afternoon
for ANZ350-353.
Gale Watch from Tuesday evening through Wednesday morning for
ANZ355.-- End Changed Discussion --
&&
$$
SYNOPSIS...BR/JT
NEAR TERM...BR/DS/JT
SHORT TERM...BR
LONG TERM...JT
AVIATION...DS
MARINE...BR/JT
HYDROLOGY...BR/JT
TIDES/COASTAL FLOODING...