000
FXUS61 KOKX 181942
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
342 PM EDT Mon Sep 18 2023

.SYNOPSIS...
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A low pressure system impacts the region today as it tracks up
the coast. High pressure builds Tuesday and remains in control
through Friday before shifting off the New England coast Friday
night into the weekend. Low pressure may impact the region
Saturday and Sunday.
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&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Deepening low pressure system just offshore lifts north and east
this evening, as an upper trough tracks east into the region. A
broad area of steady light rain, mainly north and east of the
center, will continue to push into southern New England and out
of the local region. Behind it, more intermittent showers
persist into early evening until drier air is able to work in
tonight. Additional rainfall amounts should largely remain under
a quarter inch, except perhaps across southern CT where enhanced
jet dynamics with the incoming trough may help overcome the
relatively weak mid level lapse rates and produce locally heavy
downpours.

Temperatures overnight generally bottom out in the 50s, though
parts of the urban metro may hang near 60. Followed a blend of
NBM and HRRR guidance for this update.
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&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY/...
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Drier conditions return into midweek as low pressure exits and high
pressure enters. The H5 trough axis overhead early Tuesday lifts
north and east, allowing for gradual height increases through
Wednesday as ridging builds in. This will lead to a more tranquil
pattern the next couple of days.

An increased pressure gradient between the departing low and
building high will elevate the flow a bit Tuesday. Northwest winds
10 to 15 mph with a few gusts 20 to 25 mph early in the day should
lighten by late afternoon. Other than a bit of fair weather cu,
sunshine prevails. With the boundary layer mixing to around 800 mb
per BUFKIT soundings, temperatures should be around normal for mid
September, with highs generally in the mid 70s Tuesday.

A similar tale on Wednesday, with surface high pressure to the west
maintaining the northerly flow and dry air mass. Abundant sun
can be expected with little cloud cover during the afternoon
hours.
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&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
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There has been no significant change to the long term and have
largely followed the NBM during the period.

Deterministic models and ensemble means are in good agreement with
the larger scale pattern into the upcoming weekend. Ridging aloft
will build over the northeast Wednesday night through Friday. As a
result, high pressure will be in control with tranquil conditions
for the end of the week. At the same time, southern stream energy
will undercut the ridge and form a broad trough over the southeast.
High pressure both aloft and at the surface begin to shift offshore
this weekend. The modeling has continued to trend towards an
organized low pressure developing along or off the southeast coast
Friday into Saturday. To the north of the low, an inverted trough
appears to set up as the surface high moves off the New England
coast.

The models diverge on the timing, placement, and strength of the
aforementioned low pressure. However, trends are beginning to signal
that moisture will increase from south to north this weekend. The
ensembles show varying solutions with regard to the evolution of the
track of the low pressure with some lifting it northward Saturday
towards the Middle Atlantic while others hold it near or over the
southeast into Sunday. These differences are handled well within the
model consensus. PoPs have been increased a bit this weekend, but
still remain in the chance category. The NBM probabilities of
greater than 1" in any 6 hour period this weekend remain low and
less than 10 percent. These values have been similar over the last
several cycles. Unsettled conditions are possible this weekend with
potential for a soaking, longer duration rainfall event.

Temperatures through the period look seasonable, but could end up
slightly below average during the upcoming weekend with more clouds
and potential rainfall.
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&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
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An area of low pressure moves through today and east of the
region tonight. High pressure builds in on Tuesday.

Rain showers continue this afternoon with IFR to MVFR conditions.
Another round of heavier showers is possible early this evening with
perhaps more IFR visibilities before all rain comes to an end
tonight.

There could very well be some fluctuation between MVFR and IFR
through the early evening. Some occasional brief LIFR will be
possible.

VFR eventually returns tonight as rain showers taper off from
west to east.

Winds are near to less than 10 kt. The winds will transition from
the E direction this afternoon to a more NW direction going into
tonight. Tonight into Tuesday wind speeds increase to near 10-15 kt.
A few gusts near 15-20 kt are possible tonight.

More frequent gusts to near 20-25 kt are expected on Tuesday,
generally in the late morning and afternoon.

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

End time of rain showers could be off by 1-2 hours.

Timing of end of IFR and MVFR could be off by 1-3 hours.

Categories could very well fluctuate between MVFR and IFR
before 00Z.

OUTLOOK FOR 12Z TUESDAY THROUGH SATURDAY...

Tuesday through Friday: VFR.

Saturday...MVFR possible with a chance of rain showers. E gusts
near 15-20 kt.

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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An increasing northwest flow develops tonight behind departing
low pressure, and gusts on the ocean waters may be near 25 kt
at times. In addition, southeast swells will be increasing from
distant Hurricane Nigel, with ocean seas reaching SCA levels.
The seas will remain elevated through Tuesday, and possibly into
Tuesday evening before lowering. A Small Craft Advisory remains
in effect for these waters tonight and Tuesday. Swells could
linger into Wednesday, and seas may be near SCA levels east of
Moriches Inlet.

Winds on the waters should remain below SCA levels Wednesday
through Friday. A steepening pressure gradient then brings
increasing winds and potential for SCA gusts, especially on the
ocean on Saturday. Elevated seas are possible on Thursday with
E-SE swells from Nigel. Seas may also become elevated above 5
ft on Saturday to the north of low pressure near the southeast
coast.

Monitor https:/www.weather.gov/okx/tropical or
https:/www.nhc.noaa.gov for the latest NHC forecasts on Hurricane
Nigel.
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&&

.HYDROLOGY...
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Localized nuisance flooding will be possible in heavier downpours
into this evening.

No hydrologic impacts are anticipated Tuesday through the end of
the week. Uncertainty exists in the timing and amounts of
potential rainfall for the upcoming weekend.
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&&

.TIDES/COASTAL FLOODING...
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There is a high rip current risk for all Atlantic-facing
beaches on Tuesday given 3 to 5 ft swells with 8 to 10 second
periods.

This should begin to lower on Wednesday, with a moderate risk in
place for all beaches.
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&&

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

$$

SYNOPSIS...DR/DS
NEAR TERM...DR
SHORT TERM...DR
LONG TERM...DS
AVIATION...JM
MARINE...DR/DS
HYDROLOGY...DR/DS
TIDES/COASTAL FLOODING...DR