Discussion on 2023-04-24

000
FXUS61 KOKX 242239
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
639 PM EDT Mon Apr 24 2023

.SYNOPSIS...
An upper level low will continue to spin near Lake Huron through
Tuesday. High pressure will slowly build toward the area into
Wednesday, while a series of weak upper level disturbances move
across. A weak low pressure trough and surface front will then move
across Wednesday night into Thursday. High pressure returns briefly
Thursday night. Deepening low pressure passes to the south Friday
into Saturday night. Another low deepening to the west impacts the
region Sunday into the beginning of next week.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --The forecast is mostly on track. Only minor adjustments made to
some hourly grids.

Lake clouds will continue to spill into the area from the nw into
the early eve, then will tend to dissipate thru the ngt with
subsidence and the loss of llvl instability. Clouds have been a bit
more extensive than the NBM suggests per stlt, so went abv the
guidance thru the first half of the ngt.

There could be a few sprinkles across the interior, particularly the
lwr Hudson Valley, until close to sunset. Thereafter, chances
decrease.

With a broad area of high pres over the region, winds will be lgt
overnight. As skies clear late, good radiational cooling is expected
for a few hours before dawn. As a result, went with the colder blend
of the MET/MAV as opposed to the milder NBM guidance. If the clouds
hang in longer, temps will verify warmer.

No changes to the frost advy attm. If clouds linger, temps may end
up too warm. On the other side of the cwa, less cloud cover is more
likely, so areas in the pine barrens may drop even colder than fcst
with some patchy frost there. No advy for those areas with low
confidence and less than half of the zone close to criteria.-- End Changed Discussion --

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Upr low remains over Ontario on Tue. The modeling indicates an h3
jet streak coming thru during the day, along with some low CAPE and
no CIN. This setup should allow for clouds to blossom, along with at
least isold shwrs. Extended pops further s than the NBM suggests
based on the environment. Cloud bases should be pretty high around 5-
6 kft per the time heights. The shallow convection does have the
moisture in the -2 to -10C zone, so some graupel and perhaps an
isold lightning strike also possible. Maybe a little enhancement to
winds invof shwrs with the dry llvls.

Otherwise, a lgt wly flow with temps around 60. The NBM looked
reasonable based on mixing and guidance from the MOS.

Clouds and shwrs are expected to dissipate quickly in the eve, with
clearing skies overnight. Temps should drop off again in the
sheltered areas, so some additional frost products possible,
generally for the same areas. Maintained frost in the grids but did
not issue an advy attm. Went blw the NBM, going closer to a blend of
the MET and MAV.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
An upper low remains across southern Canada Wednesday into Thursday.
At the same time a weak jet streak to our south will leave us in the
left exit region allowing for some upper-level divergence,
increasing our cloud cover. This will occur with a weak front that
will push through in the afternoon to night on Wednesday, exiting
Thursday morning. There will be a chance for showers along the
frontal passage. Some weak ridging by Thursday afternoon allows for
partly sunny skies, with cloud cover expected to remain partly
cloudy Thursday night. This ridging will weaken on Friday. A
shortwave moving into an upper low will amplify a trough through the
central states Friday into Saturday, and then evolve into a
negatively tilted trough that will affect the area Sunday into the
beginning of next week. High pressure remains to the north into the
weekend, moving east Sunday. This high will influence the track of a
deepening low with an inverted trough that will move south of the
area Friday into Saturday night. Rain chances will increase along
the northern periphery of this system, bringing chance POPs on
Friday and Saturday and bringing 15-20 mph wind gusts. Sunday into
Monday a deep trough to our west will become surface based and track
closer to our area. The triple-point of a frontal system will track
over our region Sunday, bringing with it ample moisture and lift.
Most models bring in PWATs of 1.1-1.3" inches which matches or
exceeds SPC`s 90% sounding climatology for the area. Moderate to
heavy rainfall may become a concern on Sunday, but for now it is
just something to monitor, as it is still 7 days out with a good bit
of uncertainty on the track and position of the surface frontal
system and associated trough. An increasing pressure gradient ahead
of the system will increase winds through Sunday with gusts up to 30
mph. Moisture may decrease on Monday, bringing rain chances and
cloud cover back down, but chances still remain in the forecast
for Monday.

Temperatures through the extended period will be near seasonal
normals and used the NBM.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A weak surface trough remains over the area into this evening. High
pressure will otherwise build in through Tuesday with VFR conditions
through the TAF period.

W-WSW winds this afternoon around 10 kt or less except for south
facing coastal terminals with a SSW-S sea breeze. Winds will weaken
after sunset, becoming SW-W through the night.

A light NW flow is expected Tuesday morning increasing to 10 kt or
less by afternoon. Winds may back towards the W or SW in the
afternoon near the coast, but a S sea breeze looks unlikely.

 ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
A few gusts around 15 kt possible at KEWR and KTEB this afternoon.

Wind direction at KLGA may be variable through 22z.

OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY...

Tuesday Afternoon-Night: VFR.

Wednesday: VFR. A chance of showers in the late afternoon into the
night.

Thursday: VFR. Slight chance of a shower.

Friday: VFR. E wind gusts 15-20 kt.

Friday Night-Saturday: Chance of MVFR. Showers possible. E wind
gusts 20-25 kt.

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

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

&&

.MARINE...
Winds and seas will remain blw sca lvls thru Thursday night
with a weak pressure gradient in place. An approaching and
deepening low pressure system to the south will increase an
easterly flow across the waters during Friday and Friday night
with ocean seas building to over 5 feet during Friday. Wind
gusts on the ocean waters will be around 25 kt Friday and Friday
night, with a chance of 25 kt on the remaining waters during
Saturday.

&&

.HYDROLOGY...
Rainfall expected on Sunday could be moderate to potentially heavy
at times. Exact hydrologic impacts are still uncertain at this
time.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Frost Advisory from 1 AM to 9 AM EDT Tuesday for CTZ005.
NY...Frost Advisory from 1 AM to 9 AM EDT Tuesday for NYZ067-068.
NJ...Frost Advisory from 1 AM to 9 AM EDT Tuesday for NJZ002.
MARINE...None.

&&

$$
SYNOPSIS...12/JC/BR
NEAR TERM...12
SHORT TERM...12
LONG TERM...JC/BR
AVIATION...DS
MARINE...12/JC/BR
HYDROLOGY...12/JC/BR