Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 261456
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1056 AM EDT Sun May 26 2019

.SYNOPSIS...
A cold front approaches today and passes through this evening,
followed by weak high pressure for Memorial Day. Another warm front
will approach late Monday night into Tuesday, and remain just south
into Wednesday night as weak low pressure moves along the front just
south of Long Island. The front should lift through by Thursday
morning, followed by a cold frontal approach later Thursday. The
front may linger into Friday, then weak high pressure may build in
to start next weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
The forecast is mostly on track. Skies will continue to clear
this morning as the atmospheric column dries out. This, along
with an offshore wind component for much of the area will allow
for deep mixing and rapid heating this morning into early
afternoon. Mixing up to 800mb with temps at this level at 12-13C
during the mid-afternoon yields highs in the lower 90s across
NE NJ and parts of NYC and adjacent suburbs. Immediate south
coasts will likely be limited to upper 70s/lower 80s with SW
component to flow and hybrid afternoon sea breeze development
ahead of thermal troughing and approach of cold front.
Elsewhere, widespread mid to upper 80 degree temps, locally 90
degrees. These temps will be about 15-20 degrees above
seasonable. Surface dewpoints will keep heat index values within
a degree or two of the ambient temperature.

A cold front enters from the NW late in the day and moves through
the rest of area this evening. Ahead of it, a weak thermal trough
will develop across the region. Potential for showers and
thunderstorms will limited in spite of the surface heating and
building instability. Mid-level capping and the late timing of
dynamic lift along with limited available moisture will serve
to limit any activity to isolated/scattered. Any thunderstorms
that manage to occur could have strong wind gusts with the given
speed shear and relatively dry conditions in the sub-cloud
layer with an inverted-V profile.

Moisture increases this evening along the cold front but with a more
stable atmosphere. Still, a chance of showers and thunderstorms
remains for some areas until around midnight. Drier air pushes in
overnight behind the cold front.

There is a moderate risk of rip current development today.

&&

.SHORT TERM /MONDAY/...
Weak high pressure builds in for Memorial Day with dry weather and
less humid conditions than today. MOstly sunny with high
temperatures still above normal, but not a warm as today.

There is a low risk of rip current development on Sunday.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Much of this week will feature quasi-zonal flow aloft, with flat
ridging to the south, and a series of passing shortwave troughs
along with a nearby sfc warm front bringing inclement wx at
times beginning late Mon night. The warm front will approach
late Mon night into Tue with showers, also perhaps a few tstms
by Tue evening as mid levels destabilize, but remain just south
as a weak sfc low develops along it and ripples eastward.

The front should remain south until Thu, with one more accompanying
round of showers/tstms Wed night, then lift through Thu morning as
the flow aloft amplifies just enough in response to a weakening
upper low shearing out into the Plains states. This should make Thu
the warmest day of the upcoming work week, with highs in the 80s,
which along with dewpoints in the lower 60s, should provide
sufficient instability for afternoon/evening tstms ahead of an
approaching cold front. Storms with the front could be strong
per ECMWF/GFS consensus, with sfc-based LI -4C to -6C, mid
level flow 40-50 kt, and Maglenta and SWEAT indices as low as 3
and nearing 300 respectively. Some recent events that looked
greater in the long term have not quite panned out, but the
accompanying air mass for this event is likely to be warmer
and more humid and therefor more unstable.

The sfc front could linger nearby into Fri morning per GFS as it
aligns with the flow aloft. with only slight chance PoP this far
out in time. Otherwise weak high pressure should build in to
end the work week and start next weekend, before the next in the
train of disturbances follows possibly for next Sunday.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
A cold front approaches today and passes this evening.

VFR through this afternoon expected today. Main concern is
convection developing over Central Pa as of 15z, potentially
working into the NYC/NJ terminals between 21-23z. Scattered
thunderstorms with strong winds would be the main threat, with
brief MVFR/IFR conditions possible.

W winds 10 kt or less will increase as the morning progresses.
Winds should remain SW-W through the day 10-15 kt with gusts up
to 20 kt. The chance for a southerly sea breeze at coastal
terminals is low late this afternoon, but cannot be completely
ruled out. Winds then shift to the NW by evening, then N
overnight as they lighten.

.OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...
.Monday...VFR.
.Tuesday...MVFR or lower in likely showers. SE gusts to 20 kt
possible near the coast.
.Wednesday...Chance of MVFR or lower in showers/thunderstorms,
mainly in the afternoon and evening.
.Thursday...Chance of MVFR or lower in showers/thunderstorms.
SW wind gusts 20-25 kt.

&&

.MARINE...
Sub-SCA conditions today with W to SW winds averaging around 10 kt,
although a late afternoon southerly coastal jet of 15-20 kt is
possible for the NY Bight. Seas mostly 3 to 4 feet. Relatively
tranquil conditions expected for Monday.

Expecting quiet conds with respect to prevailing winds/seas through
the longer term. Can`t totally rule out onshore flow pushing seas
close to 5 ft on the outer ocean waters late day Tue into Tue
evening and again Thu night, or sea breezes gusting to 25 kt Thu
afternoon on the near shore ocean waters and the south shore bays of
Long Island. Tstms may also pose a hazard each late day and
evening during mid week, especially on Thu.

&&

.HYDROLOGY...
No hydrologic impacts are anticipated today/tonight and probably for
much of the upcoming week.

&&

.EQUIPMENT...
NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off
the air.

&&

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

&&

$$
SYNOPSIS...JC/Goodman
NEAR TERM...JC
SHORT TERM...JC
LONG TERM...Goodman
AVIATION...NV
MARINE...JC/Goodman
HYDROLOGY...JC/Goodman
EQUIPMENT...


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