Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 260102
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
902 PM EDT Mon Sep 25 2017

.SYNOPSIS...
A broad area of high pressure will remain over the area through
Tuesday. A cold front moves through the region Wednesday night,
followed by brief high pressure building in from the west
through late week. Another surface low and attendant cold front
pass through Friday night, followed by strong Canadian high
pressure settling in across the area through the weekend.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A 1019 high was centered from VT to the n atlc. This sfc ridge
will remain in place n of the fcst area overnight.

At the same time, stratus and fog was expanding and moving
slowly westward in a light flow. At this time do not expect that
the fog will become dense on the land, however, patchy dense fog
will be possible. Otherwise, dry weather and clear skies as
aftn cu will dissipate this eve.

A blend of guidance, which was in good agreement, was used for
temps.

A high risk for rip currents and a high surf advy remain in
effect thru Tue ngt. Nassau and NYC remain out of the high surf
advy attm with waves progged to avg blw 7 ft. This would change,
particularly for Nassau county, if the swell comes in any
higher than what is currently modeled.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Maria will slowly track nwd and the sfc high will remain in place
thru the period. This will result in a slight increase in the wind.
Morning fog and stratus is expected to burn off, at least across the
wrn 2/3 of the cwa. Time heights show moisture is shallow, but the
fog and stratus are still out there today, so it is entirely
possible it lasts thru most if not all of the day for parts of ern
CT and LI. High clouds will also increase from the sw, so sunshine
where there is not the low stuff will be somewhat filtered. With the
marine influence, the raw model data was blended in for high temps
yielding numbers several degrees blw guidance.

For the overnight, it is still uncertain how much fog will develop
with winds likely staying abv 5 kt or so. Some of the modeling is
producing measurable pcpn across portions of the area. With a lack
of lift across the area, the fcst included patchy fog and dz for the
majority of the area, with more of a mist than thick fog expected
attm. Temps were a blend of the guidance and raw model data.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
With persistent onshore flow, Wednesday morning may initially have
fog and/or stratus and perhaps some light drizzle closer to the
coast as moisture remains beneath the low-level inversion.
Conditions will improve through the day with a final stretch of well
above normal temperatures before the cold front moves through from
northwest to southeast in the evening to overnight. Overall the
front is expected to be moisture starved, with very little, if any
precipitation with its passage. Although temperatures on Thursday
will be a few degrees above normal in gusty northwest flow, dew
points will gradually lower through the day as high pressure builds
in, leading to more comfortable conditions. Thereafter, temperatures
will fall to near or slightly below seasonal values as a strong
Canadian high builds in from the northwest. Conditions will mainly
be dry, with the exception of Friday night as a weak low passes
through the area.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
High pressure remains across the region through the TAF period.

Stratus/fog back is moving onshore and impacting all terminals
except KSWF through 03z or so. It is also expected to move into
KSWF although not until around 06z. With the exception of KGON
and possibly KJFK/KISP/KBDR vsbys should not come down right
away, but should take a few hours. Some uncertainty with how low
the vsbys get overnight, but flight category will already be in
the IFR/LIFR range anyway. These low conds will continue through
12z and then start to mix out from W to E due to heating and
daytime mixing. KGON may remain MVFR through the day with the
flow becoming onshore again and then decrease around 00z again.

S/SE winds 5-10 KT will become light/vrb overnight. NE/E winds
5-10 KT develop Tue morning and shift to the SE again mainly
during the late morning/early aftn.

     NY Metro Enhanced Aviation Weather Support...

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

KJFK TAF Comments: Timing of VFR returning Tue morning may be
+/- 1-2 hours.

KLGA TAF Comments: IFR expected to move in between 02z and 03z.
Timing of VFR returning Tue morning may be +/- 1-2 hours.

KEWR TAF Comments: IFR expected to move in between 03z and
04z. Timing of VFR returning Tue morning may be +/- 1-2 hours.

KTEB TAF Comments: IFR expected to move in between 03z and
04z. Timing of VFR returning Tue morning may be +/- 1-2 hours.

KHPN TAF Comments: IFR expected to move in between 03z and
05z. Timing of VFR returning Tue morning may be +/- 1-2 hours.

KISP TAF Comments: Timing of VFR returning Tue morning may be
+/- 1-2 hours.

.OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY...
.Tuesday night-Wednesday...MVFR to IFR possible with patchy
fog and/or stratus and a low chance of showers.
.Wednesday night-Thursday...MVFR or lower possible with isolated to
scattered shower activity.
.Thursday night-Friday...VFR.
.Saturday...Mainly VFR, except MVFR possible in any showers.

&&

.MARINE...
Stratus and fog, with areas of dense fog, were moving into the
forecast waters from the east and will spread westward through
this evening and into late tonight. Visibilities may fall to as
low as 1/4 nm at times, but will also be generally under 1 nm.
The fog is expected to persistent into Tuesday morning, with
improvement across the western waters first, and may be earlier
than 14Z Tuesday. A dense fog advisory has been posted for all
but the New York Harbor through 14Z Tuesday.

Swell associated with Maria will continue to increase thru Tue.
A sca for seas therefore remains in effect thru Tue ngt.
Otherwise, winds will remain lgt thru the period.

Lingering swell from T.C. Maria will likely allow seas to remain
at SCA-levels through late week, before gradually subsiding this
weekend as high pressure builds from the north. There will be a
chance for winds around 15 to 20 kt with gusts 25 to 30 kt on
Thursday following a cold frontal passage, but otherwise winds
will remain below SCA-levels.

&&

.HYDROLOGY...
No hydrologic impacts expected the next 7 days.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Rip Current Risk through late Tuesday night for NYZ075-
     080-081-178-179.
     High Surf Advisory until 6 AM EDT Wednesday for NYZ080-081.
NJ...None.
MARINE...Dense Fog Advisory until 10 AM EDT Tuesday for ANZ330-335-340-
     345-350-353-355.
     Small Craft Advisory for hazardous seas until 6 AM EDT
     Wednesday for ANZ350-353-355.

&&

$$
SYNOPSIS...JMC/MD
NEAR TERM...JMC/MET
SHORT TERM...JMC
LONG TERM...MD
AVIATION...
MARINE...JMC/MD/MET
HYDROLOGY...JMC/MD



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