discussion on 2023-11-21

000
FXUS61 KOKX 211253
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
753 AM EST Tue Nov 21 2023

.SYNOPSIS...
-- Changed Discussion --High pressure over the region moves offshore this afternoon. A
low pressure then approaches the region tonight and moves across
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 /THROUGH TONIGHT/...
-- Changed Discussion --Forecast mainly on track this morning without any adjustments to
forecast grids for today thus far.

A chilly start to the morning as overnight temperatures dropped
into the low to mid 20s across the northern interior zones and
the LI Pine Barrens and in the mid 30s for the NYC metro. A
Freeze Warning remains in effect through 8 am this morning.
The growing season officially ends today.

Temperatures will rise into the mid 40s across northern inland
zones, while southern coastal zones on Long Island, NYC, and NE
NJ will be in the low 50s.

Weather remains quiet through late this morning as high pressure
continues to move offshore. A strong upper trough and surface
low will track eastward toward the Mid-Atlantic today and into
tonight pushing a warm front north across the area.

Rain chances begin west to east late this afternoon and into
this evening before becoming likely mid/late evening into the
night. Rain will be moderate at times, with the potential of
heavy rainfall after midnight, mostly across the southern and
eastern zones.

Winds will also increase as the low level jet pivots to the
coast tonight and a secondary low develops. Wind gusts will
range mostly between 30 to 40 mph with some higher gusts
possible. Not enough confidence in a widespread event for a wind
advisory in any of the forecast zones, but far eastern areas in
the Long Island Forks may reach gusts of 45 mph.-- End Changed Discussion --

.SHORT TERM /WEDNESDAY/...
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.

Another area of low pressure develops off of the Carolina/Virginia
coast, which may keep some light isolated showers or drizzle
Wednesday afternoon only for far eastern Long Island and far
eastern SE Connecticut with dry conditions everywhere else. The
low will then push east of the area on Wednesday afternoon with
high pressure building in behind it.

Winds will quickly weaken as the center of low pressure moves
directly overhead Wednesday afternoon, reducing the pressure
gradient.

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.

.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 /13Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --High pressure moves off the northern New England coastline this
afternoon, giving way to an approaching area of low pressure.
This low approaches tonight and moves across Wednesday.

Conditions initially VFR and expected to remain VFR going into this
afternoon. MVFR develops late with rain entering the region from the
west. MVFR trends to IFR tonight as rain becomes more steady and
occasionally heavy. The rain eventually taper off west to east
Wednesday but conditions will take longer to improve, with IFR
likely for early Wednesday morning.

Winds will become more easterly today with wind speeds increasing to
near 10-15 kt. Gusts develop this afternoon to near 20 kt. The winds
become more SE tonight and further increase to 15-20 kt with gusts
up to near 30 kt. LLWS expected to develop late tonight into early
Wednesday morning with SE winds near 50 kt at 2kft. Some locally
higher gusts will be possible at times late tonight into early
Wednesday morning. Winds will begin to switch to more S to SW within
NYC terminals and terminals to the north and west Wednesday morning
with wind speeds 10-15 kt and gusts near 20-25 kt.

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

Timing of MVFR and IFR could be off by 2 to 4 hours. There could
be fluctuation between categories tonight into early Wednesday.

Start time of wind gusts may be off by 2 to 3 hours.

OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...

Wed: IFR early with rain. Rain tapers off late morning into
afternoon. Conditions improve to MVFR in afternoon and then VFR
late in the day. LLWS possible early SE winds 45-50 kt at 2kft.
SW-W winds 10-15 kt with gusts near 20-25 kt AM. W-NW winds
10-15 kt with gusts 15-20 kt PM. Locally higher gusts possible.

Thu: VFR with NW winds 10-15 kt with gusts 20-24kt. Locally
higher gusts possible.

Fri-Sat: Mainly VFR.

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

.MARINE...
Low pressure will bring increasing winds and seas late in the
day into tonight. A Gale Warning is in effect for all waters
tonight and into Wednesday.

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. 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 this afternoon.

Total rainfall from late this afternoon through Wednesday
morning is expected to range from 1 to 2 inches. 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 tonight with
the threat of heavy downpours over for most spots by the start
of the Wednesday morning commute.to early evening

There are no hydrologic concerns Wednesday night through early next
week.

.TIDES/COASTAL FLOODING...
-- Changed Discussion --There will be an increase in surge tonight into Wednesday morning.
The timing of the highest winds and longest fetch will lead to total
water level forecasts going higher than the surge model`s median.
Used a blend of ETSS, ESTOFS and the 95th percentile of the NYHOPS
surge guidance for the total water level forecast through early
Wednesday evening. Went higher than consensus of surge guidance
due to increased SE flow, longer duration of SE flow than
previously forecast, and just the right timing of fetch, piling
of water, and timing of high tide.

Surge forecasts are mostly in the 2 to 2.5 ft range with some
locally higher surges up to 3 ft. This is on top of higher wave
action expected along the southern shorelines. Parts of the South
Shore Bays and Western LI Sound Shorelines have the higher end of
the surge, more in the 2.5 to 3 ft range.

Overall, expecting minor coastal flooding across most of the
shorelines in the forecast waters for the high tide cycles late
tonight into Wednesday morning, and therefore much of the area
coastlines have a coastal flood advisory. There will probably
be some isolated moderate coastal flooding within the South
Shore Bays in the Southern Nassau to Southwest Suffolk area
perhaps at Freeport NY or Lindenhurst NY.

For SE Connecticut and Manhattan island shorelines, they will
experience more isolated minor coastal flooding where the total
water level will just touch the minor coastal flood benchmark.
Therefore for these coastlines, there are just coastal flood
statements.

The late tonight into Wednesday morning high tide cycle will be the
main tide cycle of concern with regards to coastal flooding as winds
become more westerly for the next high tide cycle. However, while
this will preclude most additional minor coastal flooding, some
residual minor coastal flooding will still be possible for the next
high tide cycle Wednesday afternoon. This would be the case
particularly for those shorelines where water does not totally drain
out and could slosh back and forth in the basin, such as the South
Shore Bays.-- End Changed Discussion --

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from 5 AM to 11 AM EST Wednesday for
CTZ009-010.
NY...Coastal Flood Advisory from 5 AM to 11 AM EST Wednesday for
NYZ071-073.
Freeze Warning until 8 AM EST this morning for NYZ073-074-179.
Coastal Flood Advisory from 1 AM to 7 AM EST Wednesday for
NYZ074-075-178-179.
Coastal Flood Advisory from 4 AM to 10 AM EST Wednesday for
NYZ078-079-176-177.
Coastal Flood Advisory from 3 AM to 9 AM EST Wednesday for
NYZ080-081.
NJ...Freeze Warning until 8 AM EST this morning for NJZ006.
Coastal Flood Advisory from 1 AM to 7 AM EST Wednesday for
NJZ006-106-108.
MARINE...Gale Warning from 1 AM to 1 PM EST Wednesday for ANZ331-332-
340.
Gale Warning from 9 PM this evening to 7 AM EST Wednesday for
ANZ335-338-345.
Small Craft Advisory until 6 PM EST this evening for ANZ350-
353-355.
Gale Warning from 6 PM this evening to 1 PM EST Wednesday for
ANZ350-353.
Gale Warning from 6 PM this evening to 7 AM EST Wednesday for
ANZ355.

LONG TERM...JT
AVIATION...JM
TIDES/COASTAL FLOODING...JM