223
FXUS61 KOKX 041917
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
317 PM EDT Sat May 4 2024

.SYNOPSIS...
High pressure remains in place along the New England coast into
tonight. A cold front then slowly approaches from the west on
Sunday through Monday, stalling to our south. Weak high
pressure moves in Tuesday into Wednesday morning before a low
from the west arrives on Wednesday bringing the stalled boundary
to our south through as a warm front. The low exits the east
Wednesday night as a new low moves into the Great Lakes. A
stalled boundary between these two systems lingers over the area
Thursday with the low moving into New England and lingering
through through Saturday.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
High pressure across the Canadian Maritimes will maintain a
persistent onshore flow through the weekend, and lead to cooler
than typical temperatures for early May.

A weak area of low pressure will pass well to the northwest through
the Upper Great Lakes, sending a slow approaching frontal boundary
toward the region tonight. A few light/brief showers will be
possible for areas well west of NYC this evening. Otherwise it
should be dry with thickening mid level clouds into this evening as
the ridge axis shifts offshore, allowing deeper moisture to advect
into the area in the SW flow. Chances for showers will then increase
overnight expanding eastward across the area.

With the return flow and cloud cover, temperatures tonight will
be in the mid to upper 40s.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
By Sunday, as the front continues to make progress eastward, plenty
of deep moisture in the column and weak lift should instigate shower
activity by the mid morning, at least for the western half of the
region, before spreading east by the afternoon. Showers may continue
intermittently into Sunday night before tapering west to east. QPF
appears light with this activity, generally ranging from a quarter
to a half inch. Skies will be overcast for much of the day tomorrow
which will support cooler temperature in the mid to upper 50s across
the region and upper 40s to low 50s across the region Sunday night.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
A cold front on Monday will lead to any lingering showers from
overnight clearing in the morning north to south, in the direction
of the front, with the front expected to fully push through by later
in the day on Monday. Slight chances still could linger in southern
and western zones into the day, closer to the frontal boundary,
which ends up stalling to our south.

Upper-level ridging sets up on Monday into Tuesday in tandem with
surface high pressure centered over the Great Lakes, then over the
northeast on Tuesday. This will lead to warmer temperatures around 5-
10 degrees above average and keep things mostly dry, though a slight
chance for afternoon showers is still a possibility in western
zones.

The ridge will flatten on Wednesday helping direct a developing
surface low over the Great Lakes on Tuesday night into our area on
Wednesday. Associated with this low will also be a mid-level
shortwave bringing in some increasing mid-level energy. This low
will lead to the stalled frontal boundary to our south to advance
through as a warm front on Wednesday with increasing PWATs of 1.25-
1.35". Given these factors, scattered showers are expected. Isolated
to scattered thunderstorms may also occur with the latest model
guidance hinting at decent amounts of available instability,
particularly in western areas where daytime surface heating will
most impactful.

This low will push east Wednesday night into Thursday morning as a
strong surface low develops over the Great Lakes. A stalled front
will develop between the exiting low to the east and the approaching
low from the west Wednesday night. Moisture looks to drop around
this time frame, so POPs may drop Wednesday night because of brief
high pressure nosing in from the north. The stalled front will
eventually attempt to slowly advance through on Thursday as a warm
front as the low to the west gets closer, returning a stronger
onshore flow. This will also advect higher PWATs of 1.35-1.45" into
the area, increasing POPs again. The increased onshore flow will
lead to warm air advection at 850mb with model guidance also hinting
at locally stronger FGEN at 850 mb. CAPE appears lower than
Wednesday, but with more forcing in place, isolated to scattered
thunderstorms could occur through the area Thursday afternoon and
evening.

Friday into Saturday low pressure will linger across New England
which could lead to occasional showers as an upper-level trough
deepens over the area from the west.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
High pressure remains in place into late tonight, then weakens
through Sunday as a frontal system slowly approaches to the west.

VFR into early evening, then MVFR ceilings develop later this
evening, around 03Z, then ceilings lower to IFR late
night/toward Sunday morning, there is some uncertainty with the
timing of lowering to IFR, and remaining IFR through the
remainder of the forecast.

A shower is possible in the NYC metro area this afternoon into
early this evening, and introduced a VCSH. There is then another
chance of showers late tonight into Sunday morning before
showers become likely Sunday afternoon.

ESE-SE winds around 10kt, ore less through the TAF period,
except at KLGA where NE winds shift to SE late this afternoon.


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

Winds at KLGA remain NE until late this evening, and may be
toward 00Z Sunday before winds become SE.

Timing of IFR onset is uncertain, and may be a couple of hours
later than forecast.

OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY...

Sunday afternoon: IFR with showers.

Monday: IFR to MVFR in the morning, then MVFR, becoming VFR in
the afternoon. A slight chance of showers, an isolated
thunderstorm possible.

Tuesday: VFR, becoming MVFR to IFR late at night.

Wednesday: MVFR or lower with a chance of showers. Isolated
thunderstorms possible in the afternoon.

Thursday: MVFR with showers likely, isolated thunderstorms
possible.

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

&&

.MARINE...
Sub-SCA conditions can be expected through the weekend with high
pressure along the New England coast maintaining an easterly or
southeasterly flow across the waters and speeds generally at or
under 10 kt.

Winds and seas are expected to stay below SCA conditions through
Friday.

&&

.HYDROLOGY...
There are currently no hydrologic concerns through next week.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides will increase with the approach of a new moon
Tuesday night along with the threat of minor coastal flooding each
night through this period and possibly including Wednesday night as
well.

A coastal flood statement has been issued for this evening`s high
tide cycle across Southern Fairfield County with benchmarks expected
to be just reached in a few spots. Statements may be expanded to
include Southern Westchester and Southern Nassau Counties for Sunday
night. Advisories may eventually be needed for these zones and
Southern Queens Monday night, and even more so for Tuesday night.
Statements may be needed during this period for other parts along
western LI Sound as well as lower NY Harbor.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$