226
FXUS61 KOKX 221843
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
243 PM EDT Wed May 22 2024

.SYNOPSIS...
High pressure will be in control through tonight, then give way
to an approaching cold front on Thursday which moves through
Thursday night into Friday. Weak high pressure builds in for
Friday night. A weak trough moves through the area Saturday. A
deep low pressure system tracks through the Great Lakes and into
Canada Sunday night through Tuesday with the system`s warm
front passing north Sunday, with the cold front moving through
Monday night into Tuesday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Have bumped highs up just a few degrees to capture the latest
obs, especially across Long Island where some locations inland
and on the north shore have warmed to the upper 70s. Otherwise,
the forecast is on track.

High pressure offshore today will continue a light southerly
flow, continuing to advect a warm and humid air mass into the
region, with 850 hPa temperatures in the 15 to 17 C range. This
should translate to highs in the middle to upper 80s away from
the coast, while highs along the coast will be in the upper 60s
to upper 70s thanks to the relatively cooler ocean temperatures.

A pre-frontal trough and cold front slowly approach from the
west, with much of the day and area remaining dry. However,
there may be isolated showers and possibly a thunderstorm
across northeast New Jersey and the Lower Hudson Valley before
the day ends. While CAPE values should rise to the 1000-2000
J/kg rang for this area, and lift increases as the pre-frontal
trough moves in, not expecting anything strong or severe as
shear values are rather low.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
The pre-frontal trough and cold front continue their approach
Wednesday night, with chances for showers and an isolated
thunderstorm slowly spreading east thanks to stability
increasing after sunset.

A warm night is expected as continued southerly flow and more
in the way of clouds help to keep temperatures up. Lows should
range from the upper 50s along the coast, to lower to middle 60s
elsewhere, except upper 60s in the NYC metro area.

Better chances for stronger storms on Thursday as the cold front
begins to move through. Instability away from the coast will
once again range in the 1000-2000 J/kg range, with steep low
level lapse rates. Shear seems to be a bit of a limiting factor
for the severe threat, with 0-6 km shear of 30-40 kt. So, strong
storms with isolated severe is possible. The Storm Prediction
Center has placed the entire forecast area in a marginal threat
for severe storms, with the main threat being damaging winds,
and possibly severe hail. A number of CAMs are showing a complex
of showers and thunderstorms moving across northeast New
Jersey, NYC, and Long Island in the afternoon. However, the
instability is lower here thanks to onshore flow, but there is a
fair amount of elevated instability, so cannot rule out a
severe storm here as well.

The cold front pushes through late Thursday night into Friday
morning. The chance for showers and thunderstorms continue, but
instability should weaken with the loss of daytime heating. A
slight chance of plain showers by Friday morning transitions to
dry conditions by the afternoon with the front finally clearing
eastern areas.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Key Points:

* Temperatures remain above seasonal normals Friday night
 through Monday night.

* Potential for a few rounds of showers and possibly
 thunderstorms Saturday through Memorial Day.

Near zonal flow continues across the country Friday night into
Sunday with a more amplified trough moving into the northern plains
and Great Lakes region Sunday night into the beginning of next week,
sending a cold front through the region Monday night into Tuesday.
Weaker shortwaves will be moving through the region Saturday into
Sunday Timing uncertainties remain with the shortwaves, with the
potential for showers late Friday night into Saturday night. And
with some daytime heating a few thunderstorms will also be possible
inland Saturday. A warm front passes to the north Sunday into Sunday
night in association with the low tracking into the Great Lakes
region.
Then with the area in the warm sector for Monday, and the approach
of a cold front, showers and thunderstorms will be possible. The mid
and upper level low will remain across southeastern Canada and into
the northeast Tuesday and Tuesday night with the chance of showers
remaining. With the uncertainties followed the NBM probabilities,
and for temperatures used a blend of the deterministic and 50th
percentile.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Weak surface high pressure will remain just offshore tonight,
then drift farther out to seas late tonight into Thursday as a
cold front approaches.

VFR with sea breezes now in at all coastal/metro terminals.
Winds sustained up to 15 kt at KJFK/KLGA, and a few gusts 15-20
kt possible at KEWR/KTEB/KLGA/KHPN.

Winds diminish to under 10 kt tonight. Weakening convection
moving in from the west could impact KSWF late this evening with
thunder possible there or nearby, then some passing showers
farther east overnight.

Main shower/tstm impact from the NYC metros north/west now
looks to be in the morning from about 12Z-16Z give/take an hour,
reaching KBDR/KISP from 13Z-17Z. MVFR cond likely and brief IFR
vsby possible with this activity, and gusty winds and some hail
also possible with the stronger cells. Before that, some low
stratus and fog with IFR cond expected at KBDR/KISP/KGON late
tonight into Thu morning.

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

No unscheduled AMD expected.

OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY...

Thursday afternoon: Showers/tstms with IFR cond and gusty winds
possible especially for KSWF/KHPN.

Thursday night: Chance of showers and possibly a tstm, with MVFR
cond possible.

Friday: VFR.

Saturday: Chance of afternoon/evening showers and possibly a
tstm, with VFR cond possible.

Sunday: Mainly VFR.

Monday: Chance of showers and possibly a tstm, with MVFR
cond possible.

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

&&

.MARINE...
Sub SCA cond expected through the weekend.

&&

.HYDROLOGY...
No hydrologic impacts expected.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Air Quality Alert until 11 PM EDT this evening for CTZ005-009.
NY...Air Quality Alert until 11 PM EDT this evening for NYZ067-068.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JP/MET
NEAR TERM...JP/JT
SHORT TERM...JP
LONG TERM...MET
AVIATION...BG
MARINE...JP/MET
HYDROLOGY...JP/MET