309
FXUS61 KOKX 071420
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1020 AM EDT Tue May 7 2024

.SYNOPSIS...
A slow moving frontal boundary gets south of the area today before
lifting back north as a warm front before stalling again through mid
week. Low pressure develops to the west on Thursday and pushes a
frontal boundary through by Friday. The low and its associated front
should be east of the area to begin the weekend, potentially
followed by another cold front on Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Dry conditions continue this morning with ample sunshine.
Temperatures are rising more quickly than forecast so adjusted
temperatures through the afternoon accordingly. Adjusted highs
today as well to reflect this warm up, especially along the
coast.

The light synoptic pressure gradient along with an increasing
amount of sunshine resulting in sfc heating should promote sea
breeze development during the afternoon. The sea breeze is
expected to propagate to the north into the evening. This will
cool coastal and eastern sections down after warming
temperatures during the day. Temperatures before any sea breeze
moves in should get temperatures into the 70s for the most part,
with some lower 80s towards NYC and points west.

For tonight weak high pressure to the north will give way to a
frontal boundary across the Ohio Valley and the lower Great Lakes
which begins to advance northeast as a warm front. This will bring
an increase in cloud cover tonight, with the evening remaining dry.
After 6z however the column as a whole moistens with chances for
shower activity increasing during the pre-dawn hours and into Wed
AM. A light southerly flow should begin to nudge dew points up
towards daybreak Wed. With this have included patchy fog for now,
with perhaps an upgrade to areas of fog in subsequent forecast
packages as a warm front draws closer. Lows should average above
normal with lows mainly in the 50s, to around 60 in the metropolitan
areas.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
Lots of low clouds with some fog early, and some showers around for
Wednesday morning as the front begins to slowly nudge into the area.
Weak low pressure is expected to develop along the boundary. The
main question deals with how quickly the frontal complex can advance
to the north and east. The front should slowly press east based on
model consensus throughout the day. If this can slow and the area
can reside in the warm sector much of the day with breaks in the
clouds developing, then perhaps a few pop-up showers and
thunderstorms could develop with fx soundings indicating some
elevated CAPE on the order of 500 J or thereabouts on the GFS and
1000 to 1500 J with the NAM. However, by the time max heating takes
places the soundings may dry out enough to preclude any convective
development. At this time due to the uncertainty around the
progression of things, it seems prudent to keep chance to slight
chance PoPs in place through the afternoon along with slight chance
/ isolated thunder with no enhanced wording at this time due to the
conditionality of convective initiation. With this said SPC does
have the area under a marginal risk of severe weather on Wednesday.
Winds will likely be out of the south and should result in a large
temperature spread across the region with breaks of afternoon sun.
Temperatures by the afternoon are likely to range anywhere from the
lower 80s across western sections, to 70s, with mainly 60s across
coastal and eastern most sections. Some 50s are possible by the
start of the evening across the twin forks of Long Island with a
wind off the colder ocean.

For Wednesday night the region should be in-between weather
disturbances. Another low pressure system takes shape across the
Midwest with a frontal boundary extending east the Ohio Valley. This
boundary likely approaches towards Thu AM as a warm front as low
pressure lifts into the Ohio Valley.  After some clearing late Wed
and much of Wed night, depending on timing clouds could increase
again towards the pre-dawn hours for early Thu AM. It should remain
rain free through the night with temperatures averaging somewhat
above normal with lows in the 50s.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Mid levels show nearly zonal flow with a trough moving in Thursday
into Friday. The local region gets brief mid level ridging Saturday
before another trough approaches for Sunday into early next week.

A weakening wave of low pressure moves farther east into Thursday
with a trailing cold front that will weaken and linger to the south
of the area. Models depict a brief break in any rain or unsettled
weather, with mainly dry conditions anticipated Wednesday night into
early Thursday.

This front will eventually strengthen and move northward back
towards the area Thursday as low pressure approaches from the west.
The front will return north as a warm front but may stay south of
Long Island. Vertical forcing with low level omega increases
Thursday afternoon into Thursday night.

The center of the low reaches near the forecast area Thursday
evening and eventually moves east of the area Friday. There are some
model differences in terms of the number of waves of low pressure
and their movement.

There is forecast an increasing chance for rainfall Thursday into
Thursday night. Rain expected mid afternoon Thursday afternoon
through Thursday evening. Some elevated instability is shown to be a
possibility so there could be a few thunderstorms. Chances for rain
decrease for late Thursday night into Friday but become higher
across interior locations Friday afternoon into early Friday evening.

The models exhibit more coherence in their pressure prognostication
Friday night into Saturday as GFS, ECMWF and Canadian in that they
depict low pressure getting farther east of the region with weak
high pressure moving into the local area for the weekend. Chances
for rain lower Friday night.

Would expect mainly dry conditions for the first half of the weekend
with a brief return of high pressure. However the high pressure will
be of weak magnitude and very transient, allowing for a large trough
to approach Sunday into Sunday night before flattening out going
into early next week.

At the surface, more low pressure areas approach Sunday through
potentially Monday as well. However, model differences become more
apparent in this timeframe as well. Chances for rain increase Sunday
and Monday, mainly in the afternoon into early evening hours.

Temperatures overall are forecast to not deviate too significantly
from seasonal normal values.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
High pressure briefly returns for today. A warm front then
lifts through overnight into Wednesday morning.

VFR thru this evening, before conditions decline overnight into
Wednesday morning. Northerly flow this morning turns southerly
for most this afternoon or evening with sea breezes pushing
inland. Speeds light, at or under 10 kt. Warm front approaches
late tonight and conditions decline to at least MVFR toward or
just after 6Z Wed with low stratus, mist, and rain developing.
IFR or lower possible, particularly after 9Z Wed. Gradual
improvement late morning and return to VFR by early afternoon.

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

Timing of wind shift this afternoon/evening may be off by a
couple of hours.

Timing of sub-VFR conds Wed AM may be off by a couple of hours.
IFR possible or lower possible toward 9Z Wed and thereafter.

Low chance of SHRA or TS Wed afternoon, too low to include in
TAF at this time.

OUTLOOK FOR 12Z WEDNESDAY THROUGH SATURDAY...

Wednesday: MVFR early, IFR possible. Conds improving to VFR
by afternoon. Chance of showers or isolated tstm in the
afternoon.

Thursday: MVFR/IFR. Showers likely and possibly a tstm,
especially in the afternoon and at night.

Friday: MVFR/VFR with chance of showers.

Saturday: Chance of showers with MVFR cond at KSWF, otherwise
VFR.

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

&&

.MARINE...
Winds and seas are expected to remain below SCA conditions
through Wednesday night as seas will essentially average close
to 3 ft.

Marginal SCA conditions become possible for Friday and Friday night
for mainly the ocean waters with 4 to 5 ft seas and gusts which get
closer to 20 kt. Otherwise, mainly sub SCA conditions are forecast
through Saturday, with perhaps a slight exception of marginal small
craft seas for the eastern ocean during the day Saturday.

&&

.HYDROLOGY...
WPC has placed mainly western interior portions of the areas in a
marginal risk of excessive rainfall on Thursday. The risk of
flooding from heavy rainfall appears to be limited at this time
for later this week.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides run high the next several days with a new moon
tonight.

Minor flood benchmarks are likely to be exceeded during the
evening high tide cycles tonight thru Thursday across coastal
southern Nassau, Queens, and Fairfield counties with inundation
up to a foot. Localized moderate flooding is possible during Wed
and Thu evening`s high tides, particularly in the most
vulnerable spots of southern Nassau and Queens.

Elsewhere, localized minor flooding for this evening`s high tide in
coastal Westchester, Brookyln, and northern Nassau/Queens.
Inundation up to a half foot is possible. Additional minor
flooding is possible thru Thursday evening.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...Coastal Flood Advisory from 10 PM this evening to 2 AM EDT
     Wednesday for CTZ009.
NY...Coastal Flood Advisory from 6 PM to 10 PM EDT this evening for
     NYZ178-179.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...JE
NEAR TERM...JE/MW
SHORT TERM...JE
LONG TERM...JM
AVIATION...MD
MARINE...JE/JM
HYDROLOGY...JE
TIDES/COASTAL FLOODING...