Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 201522
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1122 AM EDT Sun Aug 20 2017

.SYNOPSIS...
High pressure building into the region today, will settle to the
south and east Monday through Tuesday. A frontal system will
approach Tuesday night, and move across on region Wednesday.
Canadian high pressure will then build in through Saturday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Deep NW flow and subsidence with building high pressure in the
wake of a departing upper trough will result in a mostly sunny,
comfortably dry, and seasonably warm day today. Highs generally
in the lower to mid 80s. Late day sea breeze possible along the
immediate south coasts.

There is a moderate rip current risk for the beaches of eastern
Long Island.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
Zonal upper flow continues into Mon, and then begins to back a bit
Tuesday ahead of a longwave trough digging into the Great Lakes.

At the surface...high pressure gradually translates to the south and
southeast tonight into Monday morning. Good radiational cooling
conds tonight, with lows in the 50s across far outlying areas. 60s
to around 70 elsewhere.

As the high builds south and east, heat and humidity will build into
the region Monday into Tuesday. Highs will generally be well into
the 80s to around 90 on Monday, and upper 80s to lower 90s for
Tuesday. Low prob of heat advisory for portions of the NYC/NJ metro
on Tuesday as humidity levels climb.

Models are indicating potential for isolated diurnal convection
(along sea breeze boundary or hills) on Tuesday as instability
increases and convectively induced vort energy rotates around the
upper ridge. Low predictability on convective details at this
point.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Longwave trough digs into the Great Lakes Tue into Tue Night and
then slides into the NE US for the mid to late week. An associated
frontal system interacting with a sub-tropical airmass will bring
the next chance for organized shower and tstm activity Tue Night
into Wed. Low predictability on the convective details at this
point...contingent on timing of front/forcing with diurnal
instability.

Then a significant cool down expected for the end of the week as the
long wave trough settles into the NE US, and Canadian high pressure
slowly builds SE from Central Canada through the midweek.  This
will provide mostly sunny, dry and unseasonably cool conditions to
end the week into the weekend.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
High pressure will builds to the south into Tuesday morning.

VFR through the TAF period.

NW winds back to the WNW this afternoon with gusts 15-20KT at
most terminals. Gusts abate by early evening, with winds
becoming light and variable throughout by around midnight.

Coastal terminals, particularly KJFK could go 20-30 degrees
farther S than forecast late today. Chances of a true sea
breeze are very low.

.OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
.Monday-Tuesday Morning...VFR. SW gusts to near 20kt Monday
late afternoon to early evening with sea breeze enhancement.
.Tuesday Afternoon-Wednesday...A chance of showers and
thunderstorms with MVFR or lower conditions possible. SW gusts
20-25kt Tuesday afternoon through Tuesday night.
.Wednesday Night-Thursday...VFR.

&&

.MARINE...
Quiet through Tuesday afternoon as high pressure moves across.
Winds and seas ahead of a cold front Tuesday into Tuesday night
could bring some 25-kt gusts in the afternoon/evening, with
ocean seas building to 5-7 ft Tue night-Wed.

In the wake of the front, winds and seas should quiet down for
late week as high pressure slowly builds.

&&

.HYDROLOGY...
Dry through Monday. Then impacts from potential showers and
thunderstorms Tuesday into Wednesday are still uncertain.

&&

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

&&

$$

SYNOPSIS...NV
NEAR TERM...Goodman/NV
SHORT TERM...NV
LONG TERM...Maloit/NV
AVIATION...Maloit/JM
MARINE...NV
HYDROLOGY...NV


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