discussion on 2023-08-28

000
FXUS61 KOKX 290011
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
811 PM EDT Mon Aug 28 2023

.SYNOPSIS...
High pressure over New England slides offshore tonight. A
stationary front lifts north as a warm front Tuesday as
Hurricane Franklin remains well offshore. A cold front moves
through on Wednesday. High pressure builds in from the Great
Lakes Thursday into Friday and then remains over the area
through the weekend.

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --There were a few spotty warm advection showers across Orange
county in the Lower Hudson Valley, but the area will continue
to dissipate. Otherwise, forecast remains on track.

H5 trough digs into the Great Lakes this evening, eventually
swinging east into the Northeast by midweek. At the surface, high
pressure exits offshore as a stationary boundary over the Southeast
lifts north as a warm front.

Stationary front situated to our south will drift north tonight and
approach the region. A moist SW flow ahead of the trough is allowing
ample moisture into the region, with PWATs rising to near 2
inches across southern areas by early Tuesday. The boundary will
serve as a focus for showers as it tracks north, creeping into
southern parts of our region by daybreak or so.

Until then, cloud cover persists and thickens tonight. A few
light showers are possible in the lower Hudson Valley this
evening, but otherwise, most remain predominantly dry. After 6z
precip chances begin to gradually increase from south to north.
Towards daybreak the leading edge of convective activity may
approach far southern portions of the area. Temperatures will be
seasonable with lows in the 60s everywhere, but it remains
humid given the moist onshore flow.-- End Changed Discussion --

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
The frontal boundary lifts north into the region as a warm front,
likely stalling over the region for much of the day. A cold
front leading the incoming trough will then sweep east on
Wednesday, drying the region out as high pressure builds in
behind it.

Latest CAMs now keep the majority of the morning shower
activity passing just south of Long Island as it lifts off to
the north and east. Mid level dry air will work against the rain
making it north, and there remains some uncertainty on exactly
where this cutoff occurs, though likely setting up near or just
south of the forecast area. With this new guidance, have
accordingly shifted this delineation just a tad south, leaving
the northern half of our forecast area largely dry in the
morning, with reduced shower activity across NYC and Long
Island.

After the initial morning showers for some, a lull in precip
develops for much of the remainder of the day as the front
pushes north and we lose forcing. However, by evening, the
advancing trough will send a cold front toward the region from
the west, providing another opportunity for wet weather late
Tuesday night through Wednesday morning. Forcing from the front,
along with supportive jet dynamics overhead should allow for
widespread showers to develop and move through in the late
evening and overnight hours. Warm cloud depths will favor
efficient rain processes and and a flow close to parallel with
the boundary could lead to some training of the rain. While
widespread hydro issues are not anticipated, some ponding of
water in low- lying, urban, and poor drainage areas certainly
cannot be ruled out.

The cold front begins to pivot through Wed AM. Maintained a
slight chance of thunder with some elevated instability, but
severe thunderstorms are not expected. Rain chances lower Wednesday
afternoon behind the fropa as drier air works in and NW flow
develops. With more sunshine overall on Wednesday temperatures
will be closer to normal in the upper 70s and lower 80s.

Meanwhile in the Atlantic, while Franklin passes well east of
the area, some indirect coastal impacts are expected due to an
increasing swell and high surf. See the Tides/Coastal Flooding
section below for more detail.

Monitor https:/www.weather.gov/okx/tropical or http/www.nhc.noaa.gov
for the latest NHC forecasts on this tropical system and others.

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
This will be a quiet long term as the upper trough lifts out of the
Northeast at the onset and ridging over the mid section of the
country expands eastward. At the surface, high pressure centered
over the Great Lakes states on Thursday builds east and into the
area on Friday. While the high builds offshore for the weekend,
ridging will extend across the forecast area and down the spine of
the Appalachians. TC Idalia is forecast to pass well south of the
area and off the Carolina coast Thursday into Friday. Some clouds on
the northern periphery of the system may graze the area Thursday
into early Friday. A weak cold front then approaches from the NW on
Sunday, but looks to dissipate or stall north of the region.

Thus, looking for a dry (plenty of sun), cool start to the period
with temperatures 5-8 degrees below normal for Thursday into Friday,
then gradually warming back up into early next week.

Monitor https:/www.weather.gov/okx/tropical or http/www.nhc.noaa.gov
for the latest NHC forecasts on this tropical system and others.

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --A weak frontal boundary and wave of low pressure approach from
the south tonight into early Tuesday.

Expecting MVFR or lower cigs through the TAF period.

A batch of rain will approach the area late tonight. The bulk
of the rain looks to just pass to our south and east, but there
will still be enough showers to warrant some precipitation in
the TAF period. The best timing for showers will be after 06Z
tonight, with the best chances at KJFK and KISP. However, there
will be little impact from any showers in regards to visibility.
Any restrictions to visibility will be due to the development of
fog. However, there is some uncertainty on just how much the
fog will limit visibility. The best timing for fog is between
06Z-10Z tonight.

Winds will generally be from the east less than 10 KT and may
become light and variable at times overnight.

Some improvement will be possible late in the day Tuesday as any
IFR conditions may transition to MVFR.

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

Amendments likely this evening with changing flight categories
expected.

OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...

Tuesday night: MVFR or lower.

Wednesday: MVFR possible in the morning in SHRA, otherwise
mainly VFR.

Thursday-Saturday: VFR.

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

.MARINE...
-- Changed Discussion --An increasing SE / S swell on the ocean Tuesday will likely
result in SCA conditions by evening. Swells continue to
increase through Tuesday night, and even more so Wednesday as
ocean seas climb to 5 to 7 ft. The energetic S to SE swells will
peak at 13 to 14 seconds, creating rough conditions around
inlets through this time.

Seas are then expected to come down gradually Thu into Fri night,
with sub small craft conditions possible by late Thu night and Fri
morning. A 9 to 10 second S to SE swell is expected to linger
through a good portion of Friday.-- End Changed Discussion --

.HYDROLOGY...
Showers are expected along and ahead of a cold front that moves
through late Tuesday into Wednesday. Locally heavy downpours
are possible and could lead to nuisance flooding of urban and
poor drainage areas. The Weather Prediction Center has the
region outlined in a marginal risk of excessive rainfall.

.TIDES/COASTAL FLOODING...
-- Changed Discussion --A High Risk for Rip Currents has been issued for all but the NYC
beaches for Tuesday as more energetic long period swells arrive
from Tropical Cyclone Franklin. A high risk is then likely for
all beaches on Wednesday as the surf is forecast to build to 6
to 9 ft.

High surf and dangerous rip currents are likely to continue
into Thursday. A High Surf advisory may be needed for Wednesday
into the first half of Thursday due to 5-7 ft southerly swells
with a period of 12-14s period. Swells will be nearly
perpendicular to the coast maximizing the surf height. Combined
with the high surf, the potential exists for areas of ocean
beach erosion/flooding and for scattered areas of dune erosion
during the times of high tide Tue/Wed.

In addition, astro tides will be on the rise due to a full moon
Wed night. Many locations need only a foot or less to reach
minor coastal flood benchmarks across the south shore back bays
of western LI and the SW CT coast.

A coastal flood statement remains in effect for this evening`s
high tides for coastal Fairfield, CT. More locations like
Brooklyn and Staten Island may approach minor benchmarks Tue
night, with some gauges in the western LI south shore bays
potentially exceeding minor benchmarks for Tue night. This
potential will likely linger into the Wed and Thu night high
tide cycles as well. In subsequent forecast releases additional
coastal flood statements, along with coastal flood advisories
may be needed, especially for the western LI south shore bays.-- End Changed Discussion --

.OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --CT...None.
NY...High Risk for Rip Currents from 6 AM EDT Tuesday through Tuesday
evening for NYZ080-081-179.
NJ...None.
MARINE...None.-- End Changed Discussion --

SYNOPSIS...DR/DW
NEAR TERM...DR/DW
SHORT TERM...DR
LONG TERM...DW
AVIATION...JP
MARINE...DR/DW
HYDROLOGY...DR/DW
TIDES/COASTAL FLOODING...