000
FXUS61 KOKX 282034
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
434 PM EDT Thu Sep 28 2023

.SYNOPSIS...
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High pressure remains north of the area through Friday, while
low pressure develops off of Cape Hatteras and tracks northeast
over the Atlantic. The low heads east of the area Saturday into
Sunday. High pressure builds back into the region from Sunday
into the middle part of next week.
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&&

.NEAR TERM /THROUGH FRIDAY/...
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The modeling has generally remained consistent today across the
area. A moisture feed from the Atlc is progged to flow nwwd
into the area thru Fri, while an upr trof approaches the area,
allowing for locally hvy rainfall to be generated over the
area.

Waves of pcpn are already evident on radar late this aftn. The
airmass will continue to saturate with the flow locked in
place. The modeling indicates pwats aoa 1.5 inches across most
of the area thru Fri. Persistent frogen by late tngt thru Fri
mrng should help to focus the pcpn across the cwa. As heights
continue to fall as the upr low approaches, additional
development can be expected Fri aftn.

The CAMs are producing some extreme results, with rainfall
totals exceeding 10 inches in some models in some areas. While
this may be overdone, the signal is there for some high end
rainfall totals, particularly when considering the NAM has been
suggesting max totals in the 5-6 inch range.

Due to all of these factors, a Flood Watch has been issued for
all but Middlesex and New London counties in CT, where the
influence of the high is expected to be greatest.
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&&

.SHORT TERM /FRIDAY NIGHT/...
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The rain is expected to begin tapering off Fri ngt from west to
east aft 3Z or so as the upr low passes thru. Locally hvy rain
can still be expected until the moisture gets cutoff from the
developing sfc low over the ocean. When that occurs, the focus
of the hvy rain will transition to offshore areas. The flood
watch has been posted thru the overnight, but the threat may be
over by midnight.
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&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
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There have been no significant changes to the long term, as global
ensemble guidance is in decent agreement with the overall pattern. A
rather quiescent and generally dry period is expected along with a
warm up into next week.

Closed, positively tilted upper low ejects off the east coast to
start, as a an amplified ridge shifts eastward from the Central
Plains. The ridge builds to the east Sunday through Wednesday, with
the ridge axis overhead by Wednesday.  The ridge axis heads offshore
Wednesday night.

At the surface, low pressure heads east/southeast of the 40/70
benchmark on Saturday, with lingering showers across the southern
portions of the CWA though midday. Easterly flow will continue
through the day on Saturday, and into early Sunday, keeping coastal
sections under cloud cover for a good portion of Saturday, while the
interior should see some sun by late afternoon.  The pressure
gradient begins to relax Sunday as the surface low pulls away and
winds become more northeasterly by Sunday afternoon.

A strong high pressure then begins to dominate as it settles over
the northeast through Wednesday resulting in mainly dry conditions
for the region. Temperatures will be on the increase into midweek,
with highs in the mid to upper 70s across the NYC metro, northeast
NJ and the interior. At the coasts, highs in the low to mid 70s are
expected. Either way, these are near or just above average for the
time of year.
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&&

.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
An offshore inverted trough works toward the area today and
across the area tonight into Friday.

MVFR ceilings prevail for all but the CT terminals this
afternoon. A few showers expected this aftn for most of the
terminals. Ceilings will then lower tonight to IFR everywhere
as steady rain moves in. IFR likely prevails through Friday with
periods of rain. Rain will be heavy at times tonight into Friday.

NE winds 10-15 kt. Gusts develop to around 20 kt for the
overnight hours, primarily for the coastal terminals.

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

Occasional gusts to around 20kt possible as early as around
00z, especially at KLGA. Brief MVFR vsbys in -shra possible
this aftn and early evening. Timing of IFR onset may be off by a
few hours. TEMPO LIFR cigs might not occur late tonight and
Friday morning, but it`s also possible LIFR can prevail for a
few hours during that time.


OUTLOOK FOR 18Z FRIDAY THROUGH TUESDAY...

Friday PM: IFR and rain. NE winds G15-25 kt, highest at the
coastal terminals.

Saturday: MVFR/IFR and -shra in the morning, improving to VFR
by late. NE winds G15-20kt mainly at the coastal terminals.

Sunday and Tuesday VFR.

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

&&

.MARINE...
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A sca remains on the ocean thru Sat. There is a chance winds on
the remaining waters hit 25 kt Fri and Fri ngt, but the prob was
too low to issue a sca attm.

Sub SCA gusts are likely by Saturday afternoon, though ocean
seas remain elevated, 5-6ft, though early Monday. SCA seas
likely remain on the ocean waters during this time, subsiding to
around 5 ft by Monday.
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&&

.HYDROLOGY...
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A Flash Flood Watch has been issued for most of the area thru
Fri ngt. Rainfall amounts of 2-4 inches, with locally higher
amounts in excess of 5 inches, are possible. The placement of
the heaviest rain remains somewhat uncertain, but the modeling
is mainly keeping it in the cwa.

If worse case scenario rainfall amounts occur, major flooding
can be expected.

Another consideration is that the period of heaviest rain Fri AM
into PM will coincide with two high tidal cycles where minor
flood thresholds are expected to be reached. This will limit
storm drainage capacity for coastal locations during these
times and exacerbate flash flood threat in these areas during
these times.
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&&

.TIDES/COASTAL FLOODING...
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An approaching full moon will have rising astronomical tides (as low
as 1/4-1/2 ft needed to reach minor thresholds), combined with a
persistent and slightly strengthening E-NE flow and E wind
wave/swell today into Sat Am will have water levels solidly at minor
flood levels (up to 1 1/2 ft inundation) for vulnerable NY/NJ
harbor, Jamaica Bay, western Great South Bay, and coastal
Westchester/Fairfield communities, with localized minor elsewhere
across Long Island and NYC for the high tide cycles through at least
Saturday morning.

A bit more uncertainty on how widespread the minor coastal flooding
will be with the Saturday night and Sunday morning high tide cycles
as astronomical tides peak, but winds turn more to the N-NE and
gradually subside. Highest confidence in additional cycles of
widespread minor flooding is for the southern bays of Nassau and
Queens due to restricted tidal drainage, with perhaps more localized
minor flooding elsewhere.

In addition, continued beach erosion/escarpment will continue
through at least Saturday due to elevated water levels, 4-7 ft
breaking surf, and a strong E-W longshore current. Dune erosion
potential looks to be localized, with overwashes not expected.

Although our surf zone forecast season in over, the risk for
dangerous rip currents will continue into at least early next week
based on the wave conditions.

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

.OKX WATCHES/WARNINGS/ADVISORIES...
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CT...Flood Watch from 2 AM EDT Friday through late Friday night for
     CTZ005-006-009-010.
     Coastal Flood Advisory from 10 PM this evening to 2 PM EDT
     Saturday for CTZ009.
NY...Flood Watch from 2 AM EDT Friday through late Friday night for
     NYZ067>075-078>081-176>179.
     Coastal Flood Advisory from 10 PM this evening to 2 PM EDT
     Saturday for NYZ071.
     Coastal Flood Advisory until noon EDT Saturday for NYZ178-179.
NJ...Flood Watch from 2 AM EDT Friday through late Friday night for
     NJZ002-004-006-103>108.
     Coastal Flood Advisory until noon EDT Saturday for NJZ006-106-
     108.
MARINE...Small Craft Advisory until 8 PM EDT Saturday for ANZ350-353-
     355.
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&&

$$

SYNOPSIS...JMC/DBR
NEAR TERM...JMC
SHORT TERM...JMC
LONG TERM...DBR
AVIATION...JC
MARINE...JMC/DBR
HYDROLOGY...JMC/DBR
TIDES/COASTAL FLOODING...GOODMAN