okx-afd on 2024-05-15

261
FXUS61 KOKX 151943
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
343 PM EDT Wed May 15 2024

.SYNOPSIS...
-- Changed Discussion --Low pressure approaches from the south this evening and then
meanders just south of the area tonight before slowly pulling away
to the southeast Thursday. Weak high pressure then builds in from
the northeast Thursday night through Friday. This will be
followed by another frontal system and potential wave of low
pressure late weekend. High pressure then builds in for early next
week.-- End Changed Discussion --

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --Low pressure is currently located off the Delmarva coast and is
approaching our area as it deepens. Aloft, the associated upper
level trough becomes closed off this evening. The upper level low
and surface low slow down and meander just south of the area tonight
and early Thursday morning before pulling away to the southeast
later on Thursday.

Mainly overrunning light rain was seen earlier today and will
continue this afternoon, with some embedded heavier rain showers. As
the low gets closer to the area this evening and overnight, strong
low and mid level lift located northeast of the center of the low
will move over eastern portions of the area. At the same time,
higher pwat and slightly warmer air wrapped up in the low will get
pulled into eastern areas. This will result in some elevated
instability, with MUCAPE values of a few hundred J/kg. All 12z CAM
runs were in good agreement with consistent convective activity
over eastern Long Island and southeastern CT tonight into early
Thursday morning as the low meanders. With that, they are
spitting out some pretty high isolated QPF amounts. Given the
consistency in the guidance, forecast QPF has bumped up quite a
bit over eastern areas overall. Now expecting 2 to 3 inches
across eastern LI and southeastern CT, with locally higher
amounts possible. These higher amounts are expected to be very
isolated and confidence in any flooding is low at this time.
However, there is the potential for isolated flash flooding and
have highlighted this in the HWO. Given the elevated
instability, thunderstorms are also possible across these
eastern areas tonight.-- End Changed Discussion --

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
-- Changed Discussion --Some of the moderate to heavy rain as well as isolated
thunderstorms could be ongoing Thursday morning, but should not
continue into the afternoon. The low slowly pulls away, with
lingering light rain chances across the whole area through the
end of the day. Any isolated flood risk would be early in the
morning. We stay locked under cloud cover with the persistent
E/NE flow and highs will be in the low to mid 60s.

Ridging starts to build in aloft Thursday night as high pressure
noses down from the northwest. The area will likely be dry by
midnight Thursday night. Dry conditions expected through Friday,
with some clearing over the eastern half of the area. Highs will
be back in the low to mid 70s.-- End Changed Discussion --

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --*Key Points*

*An unsettled pattern for the weekend followed by drier weather
early next week.

*Below normal temperatures to start the period with a gradual warm
up to near or slightly above normal by mid next week.

There continues to be uncertainty in the evolution of key features
in the long term. Mid- and upper ridging to the north of the
area allows for a closed upper low to eject out of the Central
Plains Saturday night into Sunday. There are differences in the
global models with respect to this feature in terms of magnitude and
timing. One notable change with the available 12Z guidance is a
trend further south with a bit later development of the surface low
in association with the upper low. This would keep much of the
weekend dry for the area under predominately easterly flow. The
easterly flow would likely main cloudy conditions with cool
temperatures with the surface low to the south Saturday through
Sunday.

By Monday into Tuesday, model divergence continues as the more
progressive EC takes the low to the northeast and out of the region
while the GFS maintains a more cutoff solution and meanders the
surface low off the NC coast. Weak ridging builds in thereafter,
with a shortwave and low pressure system approaching from the west
late Tuesday into Wednesday.-- End Changed Discussion --

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --Low pressure off the Middle Atlantic coast slowly tracks
towards the area through tonight. The low meanders just south of
the Long Island coast Thursday.

Flight categories will be highly variable for the remain for the
rest of the afternoon. There may be fluctuations between VFR
and MVFR at NYC terminals with IFR to MVFR prevailing elsewhere.
Conditions should begin to lower back to IFR this evening and
prevail IFR into Thursday morning. Some improvement to MVFR is
expected middle to late Thursday morning.

Mainly light rain will continue this afternoon and should be
most widespread across Long Island and southern CT. Similar
conditions will continue tonight with potential for moderate to
locally heavy rainfall across eastern Long Island and southeast
Connecticut. There is chance that the light rain is intermittent
light rain over the NYC metro terminals on NW. Spotty rain is
possible Thursday morning.

E-ENE winds will become NE tonight. Lower confidence in wind
speeds and gusts through the period. Wind speeds should become
10-15 kt into this evening with gusts 18-20 kt early this
evening. Gusts likely become 20-25 kt with potential of a few
gusts to 30 kt near the coast. There is a chance gusts end up
occasional overnight. Winds shift to the NNE-N around 15 kt with
gusts 20-25 kt Thursday morning.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
Low confidence flight category and wind speed/wind gust
forecast.

Amendments likely for changing in flight categories. Timing of
IFR this evening could be off by 1-3 hours.

Wind gusts may be occasional this evening/tonight.

OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...

Thursday Afternoon-Night: MVFR to IFR. A chance of showers
especially early. NE winds G20-25kt.

Friday: VFR.

Saturday and Sunday: Mainly VFR. Chance of MVFR and showers.
SE winds G15-20kt.

Monday: VFR.

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

.MARINE...
-- Changed Discussion --Low pressure approaches the area this evening and meanders just
south of the area tonight into early Thursday. Winds and seas
will increase and Small Craft Advisories are in effect for all
waters tonight through Thursday and then lingering on the ocean
waters through Thursday night. Gusts will peak around 30 kts for
all waters, occasionally reaching 35 kts on the ocean waters.
Seas on the ocean waters will reach 7 to 10 ft with waves on the
LI Sound reaching 3 to 4 ft. Gusts will taper off Thursday into
Thursday night, with 5 ft seas lingering on the ocean through
Friday potentially.

Sub SCA conditions are likely thereafter into Monday.-- End Changed Discussion --

.HYDROLOGY...
-- Changed Discussion --Forecast rainfall totals have increased across eastern Long Island
and southeastern CT. Moderate to heavy rain is expected overnight
into early Thursday morning, resulting in 2 to 3 inches with locally
higher amounts possible. Any higher amounts are expected to be very
isolated at this time. There is a marginal risk for excessive
rainfall over these areas and isolated flash flooding can not be
ruled out, especially over southeastern CT where the flash flood
guidance is a but lower.

There are no hydrologic concerns from Thursday afternoon
onward.-- End Changed Discussion --

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Thursday for ANZ331-332-
335-340.
Small Craft Advisory until 6 PM EDT Thursday for ANZ338-345.
Small Craft Advisory until 6 AM EDT Friday for ANZ350-353-355.-- End Changed Discussion --

SYNOPSIS...DBR/JT
NEAR TERM...JT
SHORT TERM...JT
LONG TERM...DBR
AVIATION...DS
MARINE...DBR/JT
HYDROLOGY...DBR/JT