963
FXUS61 KOKX 080226
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1026 PM EDT Tue May 7 2024

.SYNOPSIS...
A low pressure system moves north of the area Wednesday, with
its associated warm front moving north late overnight into early
Wednesday morning. Another low pressure system approaches along
a frontal boundary south of the region Thursday into Thursday
night. The low pressure center moves across Friday and then east
of the region Friday night. Weak high pressure briefly builds
in Saturday before another low moves across Sunday. Weak
offshore high pressure establishes for early next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Made only minor adjustments into the overnight based on passed
hourly trends.

Patchy fog expected for Eastern Long Island and SE Connecticut
where surface flow late tonight becomes more SE and these
locations will be the last within the local forecast region to
receive more steady rainfall showers.

Weak offshore high pressure moves farther into the western
Atlantic as a mid-level shortwave over the Great Lakes
approaches from the west. Light onshore flow will aid in the
moistening of the BL and prevent temperatures from dropping too
low. Low temperatures tonight will be in the 50s regionwide
where lower 50s are more likely for areas east and upper 50s to
near 60 will be more likely for the NYC metro and surrounding
areas.

A line of convection associated with the shortwave over the
Midwest/Ohio Valley will begin to make its way into the area
overnight and into the early morning on Wednesday. This will
result in the increasing chance for showers with embedded
thunderstorms overnight into early Wednesday morning, with
highest likelihood for this activity from SW CT, Western Long
Island and NYC west through NE NJ and the Lower Hudson Valley.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
The batch of convective debris from the remnants of upstream
storms will continue to make its way through the area during the
morning. These showers and embedded storms will largely exit
the area by mid to late morning, allowing for clearing into the
afternoon for areas to the west. Clearing skies will allow for a
rapid warming of the surface as strong heating takes over
behind the departing showers. The timing and quickness of the
clearing will depend on how far east the warmth will get. As of
now, highs for the western areas like the Lower Hudson Valley,
northeast NJ, and the NYC metro will be in the middle 70s to
middle 80s. A relatively sharp gradient in high temperatures
will occur where eastern areas may only sees highs in the low to
middle 60s.

As the shortwave approaches the area into the afternoon, heights
fall as a weak trough moves overhead. Steepening lapse rates
combined with the strong surface heating will allow for the
development of moderate instability, generally 500-1500 J/kg MUCAPE,
over much of the area by late afternoon. Despite the instability, a
mid-level cap is expected to prohibit widespread storm development.
Forcing for ascent appears to be limited to closer to the shortwave
up to the north. As such, kept coverage of showers and storms into
the afternoon at slight chance to chance, with a better chance of
seeing convection for areas further north and west.

If convection develops, storms may become strong to locally severe
with the primary threats being damaging wind gusts and hail. SPC has
the area in a marginal risk for severe storms but threat diminishes
in more stable and cooler air closer to the coast and further east
where less surface heating takes place during the day and
instability will be elevated as opposed to surface-based.

The chance for storms diminishes after sunset with the remainder of
the overnight period being fairly dry, though a moist BL may allow
for the development of low stratus and fog. Lows will once again be
in the low 50s east to upper 50s west.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Upper levels exhibit active jet stream pattern across the
region Thursday through Friday. Then the jet is positioned more
to the south of the region for the weekend and into early next
week.

Mid levels convey a southward moving wide trough that gets
closer Thursday into Friday, bringing the area more positive
vorticity advection in the process. The same pattern generally
remains going through the weekend, with the trough moving
farther east of the region early next week.

At the surface, low pressure approaches the region Thursday
into Thursday night along a front south of the region. Model
differences still present with progression of the surface low,
some more recent model runs of NAM and GFS keeping low pressure
west of the region by early Friday whereas ECMWF and Canadian
keep low pressure farther east.

The low pressure center moves across Friday and then shifts
farther east of the region for Friday night. High pressure then
briefly builds in Saturday but will be quite transient, quickly
giving way to another approaching low from the north and west
Saturday night. The low moves in Sunday and Sunday night but
will be of weak magnitude. Weak high pressure establishes
offshore for early next week.

Rain showers are in the forecast much of the time Thursday
through Friday night with the next main chance of rain showers
Saturday night through Sunday. Mainly dry conditions are
forecast thereafter.

Some of the rain showers Thursday into Thursday evening could
be moderate to possibly heavy. Thunderstorms are possible Sunday
into Sunday night with cold pool aloft moving in with the upper
level trough.

Forecast high temperatures near normal Thursday, more below
normal Friday, and then near normal for the weekend. Potentially
more above normal temperatures could occur for early next week.
However, there is uncertainty.

&&

.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A warm front lifts through the region late overnight and into
Wednesday morning. A cold front moves through the region late
Wednesday and Wednesday night.

VFR until late tonight, or toward Wednesday sunrise. However,
with timing uncertainties conditions may lower a couple of hours
earlier. Showers develop with the approach of a warm front, and
shortwave energy moving through the upper midwest, toward
Wednesday morning with conditions lowering to IFR, and possibly
LIFR for a few hours as the warm front moves slowly through the
terminals. Isolated thunderstorms are possible Wednesday
morning, however, the chances are low and not included in the
forecast. Conditions improve back to VFR with the warm front
passage. Isolated showers and maybe a thunderstorm will be
possible Wednesday afternoon into the early evening with the
passage of the cold front. However, chances and confidence too
low to include at this time.

Winds remain light south to southeast overnight, and light and
variable in a few locations. Winds increase from the south to
southwest ahead of a cold front, and then become westerly and
gusty, up to 20kt, behind the front. Gusts may be briefly higher
with the initial cold frontal passage.


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

Timing uncertainties with the lowering conditions late tonight,
and may be a couple hours earlier than forecast. There is a low
chance of isolated thunderstorms early Wednesday morning.

Low chance of SHRA or TS Wed afternoon, too low to include in
TAF at this time.

OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY...

Wednesday night: VFR, except MVFR in fog at KGON. A slight
chance of thunderstorms early in the evening east of the NYC
terminals.

Thursday: MVFR/IFR. Showers likely, especially in the afternoon
and at night.

Friday: MVFR/VFR with chance of showers.

Saturday: Chance of showers with MVFR cond at KSWF, otherwise
VFR. Chance of showers at night with MVFR.

Sunday: MVFR/IFR with a chance of showers and possibly a
thunderstorm.

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

&&

.MARINE...
Winds and seas are expected to remain below SCA conditions
through Wednesday night as seas will essentially average close
to 3 ft.

Long term from Thursday through the weekend, sub-SCA conditions
forecast for non-ocean marine zones but on the ocean, potential
for SCA conditions due to seas. SCA seas forecast on the ocean
at times mainly between Thursday night through the weekend.

&&

.HYDROLOGY...
Minor nuisance flooding possible with rain showers Thursday
into Thursday evening. WPC contains much of the region in a
marginal risk for excessive rainfall for Thursday into Thursday
evening.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides run high the next several days with a new moon
tonight.

Minor flood benchmarks are likely to be exceeded during the
evening high tide cycles tonight through Thursday across
coastal southern Nassau, Queens, and Fairfield counties with
inundation up to a foot. Localized moderate flooding is possible
during Wed and Thu evening`s high tides, particularly in the
most vulnerable spots of southern Nassau and Queens.

Elsewhere, localized minor flooding for this evening`s high tide in
coastal Westchester, Brookyln, and northern Nassau/Queens.
Inundation up to a half foot is possible. Additional minor
flooding is possible thru Thursday evening.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory until 2 AM EDT Wednesday for CTZ009.
NY...None.
NJ...None.
MARINE...None.

&&

$$

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