715
FXUS61 KOKX 050601
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
201 AM EDT Sun May 5 2024

.SYNOPSIS...
High pressure remains in place along the New England coast
tonight. A cold front slowly approaches from the west into
Monday, briefly 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 THIS MORNING/...
Areas of light rain continue to move through parts of the local
Tri-State late tonight, mainly across the Lower Hudson Valley
and SW CT, though a lull in this activity should develop for a
period later this morning before rain coverage expands toward
the afternoon. Forecast remains on track.

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 THIS MORNING THROUGH 6 PM MONDAY/...
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 NIGHT 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 /06Z SUNDAY THROUGH THURSDAY/...
High pressure weakens today as a frontal system slowly
approaches to the west.

Cigs lowering to IFR in the next few hours, likely remaining IFR
through the TAF period. Aside from a shower or two possible
before 07-08z, showers become more likely this afternoon, then
remaining likely well into tonight.

ESE-SE winds around 10kt or less through this evening, shifting
more southerly late tonight.

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

Timing of IFR onset may be off by an hour or two. Chance that
MVFR cigs develop for a few hours this afternoon.

OUTLOOK FOR 06Z MONDAY THROUGH THURSDAY...

Sunday night: IFR with showers ending.

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.

Coastal flood statements may be needed for coastal Fairfield,
southern Westchester, and southern Nassau counties 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.

&&

$$

SYNOPSIS...20/BR/DR
NEAR TERM...20/BR/DR
SHORT TERM...20
LONG TERM...BR
AVIATION...JC/MW
MARINE...20/BR
HYDROLOGY...20/BR
TIDES/COASTAL FLOODING...JC/DR