449
FXUS61 KOKX 070756
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
356 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/...
A cold front will slowly push to the south of the area throughout
today. The winds will begin out of the north and northeast staying
under 10 mph, and likely closer to 5 mph at most places. 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 /08Z TUESDAY THROUGH SATURDAY/...
A cold front continues to push through the terminals, nearly
reaching the coast as of 6Z. Weak high pressure briefly returns
on Tuesday, before a warm front lifts through overnight into
Wednesday morning.

Mainly VFR, though KISP has occasionally gone LIFR tonight as
stratus moved onto Long Island. This should improve over the
next couple of hours as winds shift to the west then north
behind the frontal passage. Speeds light thru the TAF period,
at or under 10 kt. Direction goes southerly for most this
afternoon with sea breeze development. Front approaches late Tue
night and conditions quickly decline to at least MVFR after 6Z
Wed with rain and mist developing.


 ...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 MVFR conds Wed morning may be off by a couple of
hours. IFR possible toward 12Z Wed.


OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY...

Late Tuesday night: Chance of showers late with MVFR or lower
possible. Slight chance of a thunderstorm inland toward Wed AM.

Wednesday: MVFR cond expected, IFR possible. Cond improving to
VFR late day. Chance of showers. Tstms possible mainly 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...
A marine dense fog advisory remains in effect through the pre-
dawn hours early this morning. 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 are running high with the approach of a new moon
Tuesday night. Thus compared to the previous high tide earlier in
the night, perhaps a more widespread minor flooding event could
necessitate advisories for the western south shore bays and the SW
CT sound shore for the nighttime cycles from Tuesday night through
at least Thursday night. Eventually statements and / or advisories
for these 3 high tide cycles may be needed for other parts along
western LI Sound, SW Suffolk County, as well as lower NY Harbor and
Brooklyn.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Dense Fog Advisory until 6 AM EDT early this morning for
     ANZ350.

&&

$$

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