680
FXUS61 KOKX 011957
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
357 PM EDT Sun Sep 1 2024

.SYNOPSIS...
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A pre-frontal trough over the area will be pushed eastward by a cold
frontal passage tonight. High pressure will then build east through
the middle of the week, gradually moving offshore mid to late next
week. A frontal system may approach the area Friday into next
weekend.
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&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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Mean trough axis, centered over Ontario/Quebec, slides towards
the NE US tonight.

Scattered to numerous showers and widely separated bands of
tstms over LI/CT late this aft/early eve, will dissipate in
coverage and slide east through this evening as lead vort axis
slides east and with continued mid-level drying.

A localized flash flood threat thru early evening for northern
Suffolk and northern Middlesex/New London where there is
ongoing training tstm activity. MRMS multi sensor rainfall rates
of 1 1/2 to 2"/hr noted with training convection over far
northern Middlesex County this afternoon. This activity will
likely just skirt the northern tip of New London. Similar rates
evolving with activity over northern Nassau and NW Suffolk,
which may persist into NC and NE Suffolk through early eve. This
area being monitored for possible flash flooding this aft/early
eve.

Meanwhile gradual drying and clearing across NYC and points N&W
in wake of pre-frontal trough, ending shra/tstm threat. These
drying conds will gradually slide eastward through the evening.

Otherwise, cold front approaches this evening and crosses
tonight, with gusty N/NW winds bringing in a much drier Canadian
airmass.
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&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...
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Northern stream trough will slowly slide over the region Monday into
Monday Night and gradually east on Tuesday. At the surface,
high pressure gradually build in from the west on Monday and
then overhead on Tuesday.

Dry and seasonably warm conditions on Monday with gusty N/NW winds
and sct aft/eve cu development ahead of approaching secondary cold
front. Secondary cold front crosses Mon eve with reinforcing
short of Canadian airmass. The mixed low-levels should keep
temps from radiatively bottoming out, but still lows in the 40s
across outlying areas and 50s NYC/NJ metro.

Sunny and slightly below seasonable temps on Tuesday as heart of
Canadian airmass settles over the region.
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&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
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High pressure moves overhead Tuesday night into Wednesday morning,
then gradually pushes offshore Wednesday night into Thursday. Skies
are expected to be clear to mostly clear during this time frame. The
high remains offshore Friday leading to a return flow from the
south, which means increasing temperatures and dewpoints late next
week and an increase in cloud cover.

Conditions look to become unsettled next weekend as a frontal system
approaches from the west. At the same time, low pressure develops
along an old frontal boundary to the south, which also may approach
the area. Guidance still varies in timing and placement of these
systems. The 12Z GFS and GDPS bring the coastal low over the area
while the 12Z ICON keeps it far out to sea. The 12Z ECMWF develops
two coastal lows, kicking one out to sea, then another up the east
coast. Ensembles also vary, with some bringing a coastal low up the
coast into our area while others keep it far out to sea. Until this
event comes more into focus, exact impacts will be hard to pinpoint.

Highs during the long term will be in the 70s. Lows Tuesday night
into Wednesday morning will dip into the upper-40s in the interior
and into the 50s almost everywhere else. Thereafter, overnight lows
are expected to warm to the 50s and 60s by the weekend due to
increased cloud cover, warm advection, and a more humid air mass in
place.
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&&

.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
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A pre-frontal trough exits east this afternoon, followed by a cold
front passage around midnight tonight. High pressure builds in
thereafter.

VFR, except a couple more hours of sub-VFR to start with at KGON and
possibly KISP as well. Still a chance of showers over the next hour
or two, but only east of the city terminals. Iso tstm possible at
KISP before around 21z. SW winds around 10 kt will shift more
westerly towards midnight, then shifting NW-NNW around midnight
behind the cold front. Gusts 16-20kt for Monday, mainly in the
afternoon.

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

Winds may be NW-W at KLGA/KEWR until around 21z before returning SW.

OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY...

Monday through Thursday: VFR.

Friday: Mainly VFR. Chance of PM MVFR and -shra.

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

.MARINE...
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Winds and waves likely remain below SCA criteria through Friday
night. Northerly winds gusts may reach 20 kts late tonight into
both Monday morning, with occasional gusts to 25 kt possible
Monday night into Tuesday morning.

Next chance of SCA conditions not until Friday night.
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&&

.HYDROLOGY...
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Localized flash flood threat for mainly northern Suffolk County
and northern Middlesex and New London with training convection sliding
eastward through late aft/early eve. A quick 1 1/2 to 2 inches
likely in these area, with low prob of 2 1/2"+ with localized
backbuilding.

Thereafter, no hydrologic impacts are expected thereafter.
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&&

.TIDES/COASTAL FLOODING...
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Rip current activity is expected to be moderate for all Long Island
beaches on Labor Day, but may taper down to low late afternoon into
the evening. Rip currents are expected to be low on Tuesday.
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&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.

&&

$$

SYNOPSIS...BR/NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...BR
AVIATION...JC
MARINE...BR/NV
HYDROLOGY...BR/NV
TIDES/COASTAL FLOODING...