discussion on 2023-09-27

000
FXUS61 KOKX 271742
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
142 PM EDT Wed Sep 27 2023

.SYNOPSIS...
High pressure will be in control today, then give way to an
inverted trough moving northward along the coast late Thursday into
Friday. The low pressure trough is then expected to drift
slowly offshore Saturday as high pressure builds back in from the
north this weekend into the first half of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Made some updated to hourly fields, otherwise, the forecast is
on track. With high pressure building into northern New England,
look for partly to mostly sunny skies for today. The ENE wind
continues, although not as strong as it has been in recent days.
Due to more in the way of some sunshine temperatures should get
well into the 60s, especially across NE portions of the area as
Central and Eastern CT which will be in closer proximity to the
high, and thus little cloud cover is expected there.

For tonight look for partly cloudy to mostly clear skies, at least
to start. Late at night and closer to early Thu AM however clouds to
the south may begin to push further north, and perhaps get into
southern most sections. Lows will range from the middle and upper
40s in the cooler rural locations to the north, to the 50s along the
coast and in the metropolitan areas.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
An inverted trough off to the south and east begins to inch north-
northwestward on Thursday. The various guidance continues to show
timing differences, with the NAM continuing to be the slowest in
terms of lifting the inverted trough north. The HRRR gets a batch
of moisture and potential light rain lifting out ahead and getting
into coastal sections by the early afternoon. The RGEM, FV3, and ARW
based guidance is slower and keeps any precip to the south through
the day Thu. At this time only start to introduce slight chance PoPs
across far southern sections during the day, with it being a mostly
cloudy day and more breaks in the cloud cover further north.
However, towards Thu evening more of the guidance is suggestive of
shower activity getting into southern portions of the area. Later
Thu night the bulk of the guidance gets rain shower activity into
much of the region, thus have PoPs increasing Thu night to high end
chance to low end likely category. Also some elevated instability
may get involved towards daybreak Friday, thus some thunder cannot
completely be ruled out, especially further south. Night time temps
will average above normal due to cloud cover and increasing
moisture, with day time temps averaging about 5 degrees below normal
on Thursday.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
A 1030 mb surface high pressure remains anchored over far northern
New England and the Canadian Maritimes late this week, maintaining
an onshore easterly flow. Meanwhile, an upper trough attempts to
push east into the region on Fri, as broad surface low pressure
backs in from offshore along coast. This brings in chance to low end
likely rain Friday, with the moist air mass, relatively cool air
aloft, and nearby jet streak in the flow potentially helping to
enhance the rainfall. Can`t entirely rule out a few thunderstorms on
Friday with a hint of elevated CAPE in BUFKIT soundings, as well as
locally heavy downpours. Have slight chance thunder for the time
being.

Drier conditions return this weekend as the low slowly exits.
Ridging over the Midwest amplifies and gradually shifts east into
the local region as surface high pressure builds back to to our
west, maintaining dry weather through early next week. After days of
temperatures in the 60s, 70s make a return this weekend and early
next week. It`s possible the urban metro could eclipse 80 on
Monday, which is right around the average time of year of the
last 80 degree day. Stayed close to the National Blend of Models
for this update.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --High pressure remains across eastern Canada and the Northeast
through Thursday.

VFR through tonight. MVFR becomes likely - starting around 12z
for the city terminals and KISP, with MVFR possible for KHPN and
KSWF. ENE winds 10-15 kt this afternoon, diminishing and
backing slightly tonight before increasing back to 10-15 kt for
Thursday.

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

Chance that KJFK winds veer more easterly at times this
afternoon. A few gusts near 20 kt possible this afternoon.
Timing of MVFR onset may be off by a couple of hours.

OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...

Thursday: MVFR becomes VFR by late. Slight chance of showers.

Friday: IFR and rain. ENE wind gusts 25-30 kt, mainly along the
coast.

Saturday: MVFR/IFR and rain in the morning, improving to VFR by
late. NE win gusts 20-25 kt possible in the morning.

Sunday-Monday: VFR.

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

&&

.MARINE...
Small craft conditions are likely to continue through the entire
forecast period out on the ocean waters, mainly due to elevated seas
that stay above 5 ft, and likely closer to 6 and 7 ft for an
extended period of time. The wind regime will continue to be out of
the ENE. For Friday and into a portion of Friday night small craft
wind gusts will become increasingly likely on the nearshore waters.
Small craft conditions will continue out on the ocean through the
weekend, with marginal small craft conditions for the eastern non-
ocean waters on Saturday. The winds should back to more of a
northerly component during the weekend.

&&

.HYDROLOGY...
With wet antecedent conditions, locally moderate to heavy rain
shower activity late Thursday night into Friday could lead to
nuisance flooding of urban and poor drainage areas.

Otherwise, no hydrologic impacts are anticipated.

&&

.TIDES/COASTAL FLOODING...
Diminishing easterly winds and subsiding swells on the ocean
will reduce the areal extent of coastal flooding for tonight`s
high tide cycle. In most cases, water levels will be lower.
However, the south shore back bays of Nassau will likely have
a more widespread event with 1 to locally 2 feet of inundation
expected in vulnerable areas near the waterfront and shoreline.
Therefore, a coastal flood advisory remains in effect for
southern Nassau. Elsewhere, statements are being used to address
localized minor coastal flooding across portions of Lower NY
Harbor, SW Suffolk, and southern Fairfield in CT. While guidance
is generally indicating a non-event for SW Suffolk tonight,
models have been know to struggle at times in prolonged easterly
flow events.

For the remainder of the week, additional episodes of coastal
flooding are likely due to rising astronomical tides (as low as
1/4-1/2 ft needed to reach minor) and persistent E/NE flow and
easterly wind wave/swell.

NOTE: The Peconic River at Riverhead tidal gauge is out of
service (too high). The gauge is being looked into by our
partners at the USGS.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Coastal Flood Advisory from 6 PM to 9 PM EDT this evening for
     NYZ179.
NJ...None.
MARINE...Small Craft Advisory until 6 PM EDT Thursday for ANZ350-353-
     355.

&&

$$

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