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FXUS61 KBUF 141445
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1045 AM EDT Tue Aug 14 2018

.SYNOPSIS...
A mid-level low over northeastern Pennsylvania will slowly track
into southern New England through tonight...with fairly widespread
showers and embedded thunderstorms from the Genesee Valley eastward
slowly diminishing from west to east this afternoon and evening.
Generally dry weather with only a few widely scattered showers or
storms will then follow for Wednesday...before another area of low
pressure brings a return to more widespread unsettled weather
Thursday and Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 1040 am...the center of a closed mid/upper level low was
situated over far northeastern Pennsylvania...with an attendant
numerous to widespread showers and a few embedded thunderstorms
extending westward from the low to about the Genesee Valley. The
heaviest and most widespread rain continues to fall within a
slowly narrowing/weakening band of moderate to heavy showers and
embedded thunder draped across the Genesee Valley and western
portions of the Finger Lakes...with much lighter showers found
further to the east...as well as across far western New York
where the activity is also much more scattered.

Through the rest of today and this evening...the parent mid-upper
level low will slowly drift northeastward into western New England.
As this occurs...the numerous to widespread showers and embedded
thunder across the eastern two thirds of the area will gradually
taper off from west to east...while the scattered showers across
west of the Genesee Valley will come to an end altogether...with
some partial sunshine even working into extreme far western New
York this afternoon. With increasing ridging/drying/subsidence in
the wake of the low...we should see clearing skies from west to
east tonight...though with winds on the light side this may also
allow for the development of some patchy fog across interior sections.

As for temps...highs this afternoon will largely range from the lower
to mid 70s across the higher terrain to the upper 70s across the lake
plains...though extreme far western New York will probably break 80
degrees to the arrival of the aforementioned partial sunshine. Lows
tonight will then generally be in the mid to upper 60s for the most
part.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
Wednesday will start out dry across the region, as the upper level
low which has lingered across the region for the past several days,
continues to slowly lessen its influence on the region, as it
weakens and shifts further eastward. In its wake, sharp shortwave
ridging will crest over the eastern Great Lakes region.

By afternoon, a mid level shortwave will move east across Quebec,
with a trailing cold front approaching the Saint Lawrence Valley by
evening. This front may trigger a few widely scattered showers and
thunderstorms during the afternoon across the North Country. Lake
breeze convergence may also support a few widely scattered showers
and storms, mainly from the Genesee Valley into the Finger Lakes.

It will be a very warm day with a westerly warm advective flow
pushing 850 mb temperatures into the upper teens C, which brings
highs temperatures in the middle to perhaps upper 80s on the lake
plains of western New York, and lower 80s elsewhere. With dewpoints
well in the 60s it will feel humid out there as well.

The cold front will wash out across the eastern Lake Ontario region
Wednesday night, with any widely scattered showers and thunderstorms
ending. This will leave most of the region dry overnight, with a few
showers possibly reaching far Western NY before daybreak as the next
system approaches. Lows will drop into the mid to upper 60s in most
areas, a little cooler east of Lake Ontario.

Wet weather looks to return to the region beginning late Wednesday
night and continuing into Friday as shortwave energy and broad
surface low pressure move northeast across the region from the Ohio
Valley. Antecedent dry air should prevent any showers and
thunderstorms from beginning until well after midnight Wednesday
night across far western New York. As the surface low moves into the
southern Great Lakes Thursday and then just north of the region by
Friday, showers and scattered thunderstorms will become more
widespread. Severe weather looks unlikely at this point with weak
kinematics and abundant cloud cover. However, there will be the
threat for locally heavy rain as PWATs surge to near 2 inches.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
The majority of the rain with the system moving through the area
Friday will end from west to east Friday night as the surface low
and mid level trough exit across New England. A few scattered
showers may linger later Friday night and Saturday, mainly across
the higher terrain of the Southern Tier and east of Lake Ontario as
northerly upslope flow develops. It will turn less humid over the
weekend as a slightly drier airmass moves south out of Ontario.
Highs will be in the upper 70s Saturday, and then back to the lower
80s Sunday.

Weak high pressure will then build into the Great Lakes Saturday
night through Monday, bringing a return to mainly dry weather. The
latest 12Z GFS brings the next system into the central Great Lakes
by late Monday, but for now favored the slower ECMWF solution and
kept Monday dry. The airmass will continue to warm under building
mid level heights and weak warm advection. Expect highs back in the
mid 80s by Monday, with a gradual uptick in humidity.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
A closed mid/upper level low over northeastern Pennsylvania
will slowly push northeastward across eastern New York and New
England through tonight. In the process...numerous to widespread
showers and embedded thunderstorms from about the Genesee
Valley eastward will gradually diminish from west to east
through the rest of today and this evening... with skies then
clearing in a similar fashion tonight.

In terms of flight conditions...reductions to IFR/MVFR will remain
possible within any moderate to heavier showers/embedded storms through
early this evening...with such reductions most likely across the
Genesee Valley/western Finger Lakes (including KROC) through midday/
early afternoon...and across the eastern Finger Lakes/North Country
this afternoon. Otherwise flight conditions will be predominantly
VFR through tonight...with some IFR/MVFR possible in patchy fog
across the Southern Tier/North Country overnight.

Outlook...

Wednesday...Mainly VFR with a chance of showers and thunderstorms.
Thursday...Areas of MVFR with showers and thunderstorms
likely.
Friday...VFR/MVFR with showers and thunderstorms likely.
Saturday...Mainly VFR with a chance of a shower.

&&

.MARINE...
An upper level low will slowly pass to the south and east of the
region through today. This will continue to produce more widespread
showers and scattered thunderstorms through the first half of today
before tapering off this afternoon into tonight. Winds will remain
light today, then increase somewhat out of the west and southwest by
later Today into Wednesday creating some light chop, however
conditions will remain below small craft advisory criteria through
mid week.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR/Smith
SHORT TERM...Hitchcock/TMA
LONG TERM...Hitchcock
AVIATION...JJR/Smith
MARINE...JM/Smith
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