discussion on 2023-10-09

000
FXUS61 KOKX 081615
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1215 PM EDT Sun Oct 8 2023

.SYNOPSIS...
Low pressure deepens and occludes to the north of the area in
eastern Canada and then gradually weakens through the middle of
the week. A frontal system approaches late in the week,
possibly impacting the area by next Saturday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --With this update, have increased cloud cover by about 10-20%
for the western half of the area for the next several hours as
clouds have increased slightly more than anticipated.
Temperatures have also been overperforming by about a degree or
two. Instead of making a minor change and adjusting up,
temperatures will remain unchanged in the forecast since
increased cloud cover should halt afternoon temperatures from
becoming much warmer than forecasted. Isolated showers still
look possible for northern portions of the area later this
afternoon/evening, so POPs remain unchanged.

A drier and cooler airmass continues to establish itself in the
area behind a cold frontal passage associated with a deepening
low pressure system positioned well to the north. This low
pressure will occlude and continue to spin over Eastern Canada
through the middle of the week as it weakens.

For today, breezy conditions are expected with west winds 15-20
mph with gusts upwards of 30 mph possible. Highs will be in the
upper 50s to low 60s. With the upper level trough to the north,
ample daytime heating of the surface may allow for the
development of some showers into the afternoon but showers
should be fairly isolated and confined to the northern portions
of the CWA. Any showers that develop dissipate by evening.-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
The pressure gradient begins to relax a bit tonight and as a
result winds will continue to weaken. Combined with clear skies,
this may allow for temperatures tonight to drop into the 40s for
much of the area. Some areas in the interior may drop into the
30s.

Fairly persistent conditions are then expected on Monday with a
W/SW flow and dry conditions as the area remains at the base of
a large trough with the surface cyclone spinning well to the
north. Temperatures will once again be below average with highs
maxing out around 60.

As pieces of energy rotate around the base of the trough and the
cut off low, some additional cloud cover with possible shower
development will become possible Monday night and into Tuesday.
Capped precipitation at a low-end chance as there is uncertainty
in the development of any showers late Monday night and through
the day Tuesday. Otherwise, Tuesday is expected to be closer to
average with highs in the low to middle 60s. Shower chances
diminish by Tuesday night as the piece of energy moves to the
northeast. Lows Tuesday night are expected to be in the 40s and
low 50s.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Upper level closed low remains nearly stationary over southeastern
Canada on Wednesday before gradually shifting east Thursday into
early Friday. While a brief ridge moves over the northeast late
Friday, another closed upper level low is progged to approach,
potentially impacting the area next weekend.

At the surface, a frontal boundary continues moving offshore on
Wednesday with weak high pressure setting up across the Middle
Atlantic. Low pressure associated with the upper level closed low
over southeast Canada will continue filling/weakening as it pushes
towards the Maritimes through Friday. A surface trough or stationary
front may lie over the Middle Atlantic Thursday night into early
Friday. As the upper low pushes east, a broad trough axis may slide
across the region Thursday night into Friday, interacting with the
boundary to the south. Some weak warm advection could lead to some
light rain, which model consensus of a low chance PoP seems
reasonable at this time.

Attention then turns to the next frontal system associated with the
next upper closed low. Deterministic global models and their
ensemble means are in good agreement with the larger scale set up
heading into next weekend. However, specific details are much more
uncertain. These include the track and timing of the upper low and
associated frontal system and whether or not the primary low will
transfer to a secondary low near the coast. Individual ensemble
members indicate spread which is to be expected at this time range.
Some show a progressive system while others are much slower, with
the associated rain holding off for the second half of next weekend.
Another widespread rainfall event is possible, but more specific
details will not be fully resolved for at least several more days.
Have capped NBM PoPs at chance on Saturday given these uncertainties.

Temperatures should be near normal in the lower to middle 60s
Wednesday through Friday. Temperatures may trend below normal for
next weekend.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
Low pressure will deepen across southeastern Canada into this
afternoon, then remain nearly stationary tonight.

VFR through the TAF period.

WSW winds 10-15 kt with gusts 20-25 kt expected this morning
and afternoon. Gusts diminish after sunset with sustained
speeds falling below 10 kt overnight.

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

End time of gusts this evening may be off by 1-3 hours.

OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...

Monday: Mainly VFR. Low chance of showers at night. SW winds G15-
20kt possible in the afternoon.

Tuesday...Mainly VFR. Low chance of showers with MVFR possible,
mainly in the morning.

Wednesday and Thursday...VFR.

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

&&

.MARINE...
Gusty W winds will bring SCA to all waters through the day.
Winds diminish this evening and non-ocean waters become sub-
SCA. For the ocean, seas will likely remain above 5 ft tonight
with gradually diminishing winds.

Seas on the ocean are progged to be in the 3-5 ft range Monday
and into early Tuesday before dropping below SCA thresholds. Winds
and seas are expected to remain below SCA levels Wednesday and
Thursday.

&&

.HYDROLOGY...
No hydrologic impacts expected through Friday.

&&

.TIDES/COASTAL FLOODING...
Long period SE swells from the remnant low of Phillipe will
present the likelihood of additional beach erosion/escarpment
from an east to west sweep of 5 to 7 ft breaking surf. Because
water levels are not astronomically high, the dune erosion
threat during times of high tide is isolated. Swells subside
into tonight.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ331-
     332-335-338-340-345.
     Small Craft Advisory until 6 AM EDT Monday for ANZ350-353-355.

&&

$$

SYNOPSIS...DS/MW
NEAR TERM...BR/MW
SHORT TERM...MW
LONG TERM...DS
AVIATION...DS/DW
MARINE...DS/MW
HYDROLOGY...DS/MW
TIDES/COASTAL FLOODING...