530
FXUS61 KOKX 171934
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
334 PM EDT Tue Sep 17 2024

.SYNOPSIS...
High pressure moves offshore as a weak coastal low pressure
approaches the area from the south into the middle of the week.
Low pressure will linger just south of Long Island Thursday into
Friday before pushing further south on Saturday. High pressure
builds in from the northeast Sunday into early next week.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Surface high pressure to the northeast will continue to remain in
place tonight with a light E to NE flow advecting moisture onshore.
Upper level ridging over the Northeast will continue to erode as an
upper level trough over the Southeast approaches the area. At the
surface, a low pressure will gradually move up the coast increasing
the E/NE flow late tonight and into Wednesday.

Skies will become gradually cloudier tonight with possible low
stratus and patchy fog development late, especially in any areas
that can radiationally cool earlier in the night before the
denser cirrus shield overtakes the area. Lows tonight will be
in the middle 50s for the interior to low to middle 60s for the
coast.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/...
The weak coastal low pressure system will be just to the south of
the area, off the Mid-Atlantic coast, by midday Wednesday. In
addition to increasing the northeasterly flow, moisture on the
northern fringe of the system will begin to approach the area. There
remains some uncertainty as to how expansive any rainfall may be but
at a minimum scattered showers can be expected as early as mid-
morning Wednesday, especially for the immediate coastal areas.

The low pressure system appears to spin just to the southeast of the
area off the coast through at least Thursday. This will result in a
chance of showers for much of the area, but primarily Long Island,
through this timeframe. While any precipitation is expected to be
fairly light and intermittent, some heavier rounds of rain are not
completely ruled out, especially for eastern Long Island where the
proximity to the low pressure may enhance precipitation rates for a
time Wednesday evening into Thursday morning.

Generally, 0.5 to 0.75" of rainfall is expected for the coast with
lesser amounts to the north and west. Flooding concerns are not
expected with this system. A persistent onshore flow over the next
few days, coupled with mostly cloudy to overcast skies will result
in high temperatures being at or slightly below average with highs
Wednesday and Thursday in the low to middle 70s. Some areas to the
north and west may rise into the middle to upper 70s Wednesday,
assuming any precipitation remains closer to the coast.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
There was no significant change to the long term forecast Thursday
night through early next week.

*Key Points*

*Unsettled conditions continue with lingering chances of showers,
especially closer to the coast, for the end of the week with low
pressure lingering south of Long Island.

*Improving conditions should begin to occur Saturday, but especially
Sunday into early next week as high pressure builds in from the
northeast.

*Temperatures start out near to slightly above normal Friday into
Saturday, but will trend slightly below normal Sunday into early next
week.

Slow moving upper trough/closed low will remain over the northeast
Thursday night through Friday. The modeling has been having a
difficult time trying to resolve the location of a broad low
pressure associated with the trough. The overnight 00z 9/17 runs
largely kept the low far enough south off the Delmarva that the
majority of the showers would stay offshore. However, some of 12z
9/17 guidance has shown a bit a of a north shift with the low, which
would serve to keep some potential of showers into Friday. The
deterministic NBM PoPs Thursday night through Friday are largely in
the slight chance category except for some chance PoPs near the
immediate coast. Bumped NBM PoPs up about 10 percent given some of
the new global deterministic and ensemble guidance. The result is a
chance of showers Thursday night for much of the area with just a
chance near the coast on Friday and slight chance elsewhere. The
upper trough should begin shifting south and east Friday night into
Saturday, helping push the surface low further away from the area.

Dry weather likely returns Saturday, but some lingering clouds are
possible. Coverage of clouds should diminish further as ridging
begins to build aloft on Sunday. Surface high pressure over
southeast Canada builds down across the northeast into early next
week. The high may then shift towards the Maritimes on Tuesday as the
ridge axis slides off the New England coast.

Highs will be in the 70s on Friday, warmest across the western half
of the area. Temperatures begin to trend down beginning Saturday but
especially Sunday into early next week as cooler air advects south
in associated with the building high pressure. High temperatures
Sunday into early next look to reach the upper 60s to low 70s,
slightly below normal for this time of year. It may also remain
breezy, especially near the coast due the pressure gradient from the
building high to the northeast and departing low pressure.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
High pressure will remain centered off the New England coast through
tonight with low pressure to our south into Wednesday.

VFR this afternoon, lowering to MVFR/IFR tonight mainly in
ceilings, returning to VFR Weds afternoon with a chance of late
day showers and MVFR vsbys.

ESE-SE winds 5-10kt this afternoon, backing E this evening, then
NE overnight and Weds. Winds increase to around 10kt Weds.

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

Timing of MVFR and IFR onset tonight may be off by 1-2 hours.

OUTLOOK FOR 18Z WEDNESDAY THROUGH SATURDAY...

Wednesday PM through Friday: Periods of rain/showers possible
with with MVFR or lower conditions. NE-N gusts 20-25kt possible
mainly Thursday through Friday.

Saturday: Chance of showers/MVFR in the morning, then VFR. NE
gusts around 25kt possible.

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

&&

.MARINE...
Increased easterly flow and waves will result in SCA conditions on
the ocean zones through at least Wednesday morning, possibly
extending into the day on Thursday. Wave heights near 5 feet
with occasional marginal gusts near 25kt will be possible with
an approaching coastal low remaining south of the area through
the middle of the week.

Marginal SCA conditions are possible Thursday night. A more
prolonged period of SCA conditions is possible on the ocean Friday
into the weekend as seas build and wind gusts on the ocean likely
reach close to 25 kt. The non-ocean waters should remain below SCA
levels.

&&

.HYDROLOGY...
No hydrologic concerns with showers through Thursday with rainfall
amounts less than an inch. Locally higher amounts possible.

There are no hydrologic concerns through the weekend.

&&

.TIDES/COASTAL FLOODING...
Astronomical tides are running high this week due to this evenings
full moon. Increasing E flow will then help keep tide levels
elevated through the rest of the week and potentially into the
upcoming weekend.

Localized minor flooding is expected with high tide Wednesday
morning across the south shore back bays and across the S
Westchester and S Fairfield coast. Have issued a Coastal Flood
Statement for these locations. Minor coastal flooding may become
more widespread with subsequent high tide cycles Wednesday night
through the end of the week. A few locations could touch or exceed
moderate flooding benchmarks at the end of the week/early weekend,
especially for some of the more vulnerable locations of the south
shore back bays. This likely hinges on how much tidal piling occurs
and the strength of the easterly flow over the region. Tide levels
could be held down if the onshore flow is weaker or the wind
direction ends up more northerly.

A high rip current risk for ocean beaches continues through
Wednesday evening. A high rip current risk appears likely to remain
Thursday into the upcoming weekend with rough seas due to increasing
easterly flow.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Risk for Rip Currents through Wednesday evening for NYZ075-080-
     081-178-179.
NJ...None.
MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ350-353-
     355.

&&

$$

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