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000
FXUS61 KBUF 160819
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
419 AM EDT Tue Aug 16 2022

.SYNOPSIS...
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A weak upper level low will meander across the Northeast States
today through Thursday, bringing unsettled weather with a few
showers and widely scattered thunderstorms at times. Dry weather
will return Friday as high pressure builds back into the eastern
Great Lakes.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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Radar imagery early this morning showing an area of showers over
northwest PA drifting northwestward, clipping the southwest corner
of NY state. This area of showers will likely move a little farther
north and west through early this morning, with a period of showers
for Chautauqua and southern Cattaraugus counties. Elsewhere, a few
sprinkles and spotty light showers are found from the western Finger
Lakes westward to Lake Erie.

A broad/weak upper level low over eastern NY/PA this morning will
drift slowly east into southern New England and gradually deepen
through Wednesday morning, with an associated surface low deepening
off the New England coast. The better forcing and deeper moisture
will be found east of the upper level low and off the east coast
through the period. Meanwhile, large scale forcing across our region
will be weak and stochastic as subtle, convectively modulated
vorticity maxima orbit the upper level low. At the surface, there will
be very little in the way of a synoptic scale feature, with
mesoscale boundaries dominating. Expect the primary low level focus
to be terrain induced boundaries and weak circulations over the
Southern Tier and western Finger Lakes this afternoon.

Most of the showers through the morning hours will continue to focus
across the western Southern Tier near a weak inverted trough axis.
This afternoon diurnal instability and local terrain forcing will
take over, with showers becoming more numerous across the Southern
Tier and western Finger Lakes. Enough instability will develop to
support a few widely scattered thunderstorms as well. Farther north,
a stabilizing northeast flow off Lake Ontario will likely keep areas
along and north of the NY Thruway mainly dry from Wayne County
westward across Rochester and Buffalo. East of Lake Ontario, high-
res guidance suggests a few terrain induced showers will develop
over the Adirondacks and then drift westward towards the east end of
Lake Ontario during the afternoon and early evening.

This evening the areal coverage of showers will diminish, and any
thunder will end. Overnight, model guidance suggests another weak
inverted trough will drift across northwest PA and southwest NY,
supporting the chance of a few scattered showers. Increasing lake
induced instability may also support a few scattered showers over
Lake Ontario and Lake Erie, possibly drifting onshore at times
across Western NY.
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&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
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Heading into Wednesday, a broad negatively tilted trough will lie
across much of the Great Lakes and New England, where it`s within
this trough a closed low will deepen and engulf much of New York
State and spread eastward into Cape Cod. Throughout the day this
closed low will ever so slightly advance northward into New England.
As such, with the the close proximity of the low with respect to the
region, weak flow will remain across the region and any forcing in
place across the area will primarily be diurnally driven and
therefore expect any showers and thunderstorms to form by Wednesday
afternoon.

The aforementioned upper level closed low over New England will meet
up with a coastal low Thursday, where by Thursday night both
features will become vertically stacked. This being said, the lower
Great Lakes region will remain of the backside of the low pressure
system which will produce a marginal lake response as winds back
more north-northwest Wednesday night into Thursday and therefore
kept the slight chance and chance for lake effect rain showers
Wednesday night into Thursday. Additionally, later on Thursday
diurnally driven showers/thunderstorms will be possible once again.

Thursday night, the stacked low pressure system will continue to
progress north into the Canadian Maritimes allowing for some upper
level ridging and surface high pressure to spill across the Great
Lakes. With the incoming ridging and surface high pressure, expect
mostly dry conditions Thursday night.
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&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
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Another potent shortwave trough will dive south from the Canadian
Prairies and into the Upper Midwest Friday. Similar to the low
pressure system earlier in the work week, this feature will closely
follow suit by closing off and slowing down its progression across
the Upper Mississippi Valley through the first couple of days of the
weekend. On the bright side, the slowing progression of the trough
will support ridging, surface high pressure and consequently a
period of dry weather across the region Friday through most of the
day Saturday.

As of 00Z model guidance packages arrive, the weakening upper level
low is progged to track east late Saturday and Saturday night which
would support a chance for some scattered showers Saturday night,
mainly across Western New York. Then increasing moisture along with
diurnal heating will support better chances for showers and
thunderstorms Sunday afternoon, though the best opportunity for
showers and storms will arrive as the system nears the area at the
start of the next work week.
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&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
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A weak upper level low will continue to meander across NY/PA and New
England today through tonight, producing scattered showers at times.
Through the morning hours the majority of the showers will focus
across the western Southern Tier. The greatest coverage of showers
will occur this afternoon and early evening across the Southern Tier
and western Finger Lakes as modest diurnal instability develops,
although a few spotty showers are also possible outside of this time
and space as well. Enough instability will develop this afternoon to
support a few isolated to widely scattered thunderstorms. Any
thunder will end in the evening, with showers decreasing in
coverage.

VFR will prevail most of the time, although any heavier showers may
produce local/brief MVFR to IFR conditions. Some patchy fog may
develop across the Southern Tier later tonight through early
Wednesday morning with local IFR VSBY.

Outlook...

Tuesday night through Thursday...Mainly VFR. Chance of showers
and isolated thunderstorms with local/brief flight restrictions.

Friday and Saturday...VFR.
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&&

.MARINE...
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High pressure will remain anchored over Quebec today through
Wednesday, with general low pressure over the southeast states and
along the east coast. This will maintain an extended period of
northeast winds on Lake Ontario and Lake Erie. Sustained wind speeds
will generally be 10-13 knots, producing a light chop at times.

Forecast BUFKIT soundings over Lake Erie and Lake Ontario dont
support a chance of waterspouts today through this evening with lake
induced equilibrium levels too low. That will change overnight as
mid level temperatures cool and allow for deeper lake induced
instability to develop, bringing the chance of waterspouts by late
tonight and Wednesday morning.
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&&

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

&&

$$

SYNOPSIS...Hitchcock
NEAR TERM...Hitchcock
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...Hitchcock
MARINE...Hitchcock