Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 231805
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
205 PM EDT Tue Apr 23 2024

.SYNOPSIS...
High pressure over the area will weaken this afternoon as a
frontal system approaches from the west. The frontal system will
then move across the area Wednesday morning and afternoon.
Strong high pressure will build in from late Wednesday into
Thursday, remain over the region Thursday night and Friday, and
move offshore Friday night into Saturday. A warm front may lift
through Saturday night into Sunday, as an associated low over
the Great Lakes moves slowly eastward through early next week.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Forecast remains on track this afternoon. High pressure
continues to weaken and give way to an increasing onshore flow.
Skies will remain mostly clear for the rest of the afternoon
with some high clouds increasing from the west late. S flow
will continue to become gusty into the afternoon, strongest near
the coast. Temps along the coast may not be much different than
those of yesterday as a result, with highs 55-60, but temps
inland should be a little warmer, the 60-65 expected from
interior S CT across the Hudson Valley into NYC and NE NJ.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
Clouds should increase tonight as the frontal system approaches,
with a leading warm front bringing a chance of showers late
mainly to Orange County. S flow will continue, with lows from
the upper 30s across SE CT and ern Long Island, to the 40s most
elsewhere, to near 50 in midtown NYC.

The chance of showers will expand to cover the entire area,
first in the morning with the leading warm front, then in the
afternoon especially inland with the cold fropa. Fcst soundings
show some sfc-based instability, but do not expect thunder given
a mid level cap keeping the instability from reaching levels
colder than -10C. That said, a few showers could still produce
gusty winds to 35 mph given steep low level lapse rate and dry
sub-cloud air.

High temps on Wed will be limited to the upper 50s/lower
60s inland and out east, with mid/upper 60s for Long Island and
the NYC metro area.

Fropa Wed afternoon will be followed by a gusty W-NW flow
ushering in colder air for Wed night-Thu. Lows Wed night should
fall to the lower 40s in midtown NYC, with 30s most elsewhere
and upper 20s across the interior. Freeze conditions may once
again occur inland, all the way to the coast across SE CT, and
across the Long Island Pine Barrens, with upper 20s/lower 30s
expected. Highs on Thu should be in the lower/mid 50s, about
7-10 degrees below normal.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
An Omega blocking pattern begins to set up Thursday night and
becomes established on Friday, as a deep trough remains across
eastern Canada into the northern Atlantic, with another trough
through the Rocky Mountain region into the Plains, and a high
amplitude ridge in between. As a result systems will be slow to
move eastward into the beginning of next week. And a northern
Plains low will be slow to move into the ridge Sunday into
Monday.

With surface high pressure over the region moving offshore
Friday night, there is a lot of uncertainty with the
development and movement of a warm front Saturday night into
Sunday, as ridging remains. Regardless of the warm front, a deep
return flow sets up for late in the upcoming weekend and
temperatures initially below normal through Saturday quickly
rise to as much as 10-15 degrees above normal Saturday night
into the beginning of next week. Used the NBM guidance through
the extended period. Frost headlines may once again be needed
for the inland areas Thursday night and Friday night.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Weak off shore high pressure weakens today as a frontal system
slowly approaches from the Great Lakes through tonight and moves
through late in the day Thursday.

Generally VFR through the TAF period. A chance of showers late
tonight/toward Wednesday morning. There is a low chance, low
confidence, of MVFR in the showers. Best chances for any MVFR
conditions look to be between 10Z and 14Z Wednesday for the city
terminals.

S winds this afternoon at 10 to around 15 kt with gusts 20 to 25
kt. Southerly flow gradually weakens tonight, but then increases
again early Wednesday morning and shifts to the SW at 10 to 15
kt with gusts 20 to 25 kt. A shift to the W then WNW is expected
by mid then late morning/early afternoon.


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

Gusts may be more occasional, and more likely, and stronger,
late in the afternoon.


OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...

Wednesday: VFR, SW winds 10-15G20-25kt, becoming W-NW in the
afternoon, then northerly late at night 5 to 10kt.

Thursday-Saturday: VFR.

Sunday: VFR. Low chance of MVFR in showers.

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

&&

.MARINE...
Quiet cond to start will give way to a strengthening S flow this
afternoon and tonight. A southerly jet along the Jersey shore up
into the NY Bight and lower NY Bay will gust over 25 kt, so SCA
continues there. SCA cond should expand eastward later tonight
into Wed, with gusts up to 25 kt and seas 4-7 ft.

W-NW flow following cold fropa Wed afternoon will likely gust
to 25-30 kt on all waters from late day Wed into Wed night.
Extended SCA only for the ocean waters into this time frame for
now.

With high pressure in control Thursday night into Saturday,
moving offshore Saturday night, winds and seas across the
forecast waters should then remain below advisory levels.

&&

.FIRE WEATHER...
Issued an SPS for Lower Hudson Valley of NY for elevated fire
spread this afternoon given combo of min RH 25-30 percent and S
winds gusting to around 20 mph.

SPS for NE NJ remains for elevated fire growth potential given
combo of min RH 25-30 percent, S winds gusting to 20-25 mph, and
drying fuels, for this afternoon until around sunset.

A similar combo will be in place across the rest of the NYC
metro area, much of the lower Hudson Vally, and interior S CT
along the I-84 corridor.

After a cold frontal passage Wed afternoon, cond may be even
more conducive for fire growth in the NYC metro area and NE NJ
given similar RH and W-NW winds gusting to 25-30 mph. This will
depend on how quickly RH drop and whether wetting rains occur
ahead of and with the frontal passage.

&&

.HYDROLOGY...
No hydrologic concerns through the upcoming weekend.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until midnight EDT tonight for ANZ338.
     Small Craft Advisory from 5 AM Wednesday to 6 AM EDT Thursday
     for ANZ350.
     Small Craft Advisory from midnight tonight to 6 AM EDT
     Thursday for ANZ353.
     Small Craft Advisory from 6 PM this evening to 6 AM EDT
     Thursday for ANZ355.

&&

$$

SYNOPSIS...BG/MET
NEAR TERM...BG/DS
SHORT TERM...BG
LONG TERM...MET
AVIATION...JP
MARINE...BG/MET
FIRE WEATHER...
HYDROLOGY...BG/MET


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