013
FXUS61 KBUF 251832
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
232 PM EDT Tue Aug 25 2026

.WHAT HAS CHANGED...
Minimal changes made with this forecast update.

&&

.KEY MESSAGES...
1.) Rain showers, some of the lake-effect variety, end this
early evening and will be followed by fair weather through
Wednesday.

2.) Periodic showers and thunderstorms are expected this
Wednesday night through Friday.

&&

.DISCUSSION...
Key Message 1...Rain showers, some of the lake-effect variety, end this
early evening and will be followed by fair weather through Wednesday.

NW`erly flow aloft becomes W`erly tonight as a high at the
surface and aloft builds from the central Great Lakes and
vicinity. Primarily fair weather is expected through tonight as
stabilizing subsidence accompanies the ridge. However, the
passage of shortwave troughs embedded in the NW`erly flow aloft
and attendant surface trough axes coinciding with weak diurnal
boundary layer instability will continue to generate scattered
rain showers across the Eastern Lake Ontario Region and vicinity
through this early evening. In addition, isolated to scattered
lake-effect rain showers focused generally southeast of Lake
Ontario, amidst a NW`erly to WNW`erly mean low-level flow of
sufficiently-cold and moist air over/downwind of the ~23C lake,
are expected to end by around sunset this evening as lake-
induced CAPE wanes via a lowering subsidence inversion
accompanying the ridge. A few lake-effect sprinkles are
possible generally southeast of Lake Erie through this very
early evening before ending amidst the waning lake-induced CAPE.
Highs should reach the mid 60`s to mid 70`s late this afternoon.
The coolest highs are expected in the higher terrain of the
Western Southern Tier and Eastern Lake Ontario Region. Partial
clearing and easing surface winds should contribute to lows
reaching the 50`s in most locales around daybreak Wednesday, but
mid to upper 40`s are expected in some of the deeper valleys of
the Western Southern Tier and Black River Valley, where cool
air drainage will complement nocturnal cooling. The efficient
nocturnal cooling and lingering low-level moisture from recent
rainfall should result in river and lake valley steam fog, and
patchy radiation fog, late this evening and especially during
the predawn hours through shortly after daybreak on Wednesday in
the Western Southern Tier, Finger Lakes, and Eastern Lake
Ontario Region. On Wednesday, the ridge at the surface and aloft
will begin to exit toward New England and net low-level WAA
will impact our region along the western flank of the surface
ridge. The WAA, continued fair weather, and intervals of
sunshine will allow late afternoon highs to reach the 70`s to
lower 80`s.

Key Message 2...Periodic showers and thunderstorms are expected this
Wednesday night through Friday.

During Wednesday night, the aforementioned ridge at the surface
and aloft will continue to exit E`ward and allow a warm front
to sweep NE`ward through Western and Central NY as a shortwave
trough approaches from the western Great Lakes. The front will
usher-in a warmer and more humid air mass originating over the
Gulf. Scattered showers and thunderstorms are expected, especially
after midnight, as weak CAPE, including elevated CAPE, is
released by the following: moist isentropic ascent along the
upper-reaches of the front and ahead of the shortwave trough
axis; low-level convergence/moist ascent along the surface warm
front. Lows should reach the mid 50`s to mid 60`s around
daybreak Thursday as net low-level WAA ahead of and behind the
warm front and an increase in humidity contribute to a milder
night.

On Thursday through Friday, multiple shortwave disturbances are
expected to traverse our region generally from west to east. At
the surface, a cold front should sweep E`ward through Western
and Central NY Thursday evening through Friday morning. Behind
the front, a surface ridge should build from the Upper Midwest
and vicinity. Late afternoon highs should reach the 70`s to
lower 80`s on Thursday. Lows should reach the 50`s to lower 60`s
around daybreak Friday. Highs should reach the 70`s late Friday
afternoon as a somewhat cooler air mass overspreads our area
behind the cold front.

Scattered showers and thunderstorms are expected along and
ahead of the front as sufficient instability, including elevated
CAPE, is released by the following: moist isentropic ascent
ahead of shortwave trough axes; low-level convergence/moist
ascent along surface trough axes accompanying the shortwave
troughs and the cold front; downshear outflow boundaries
interacting favorably with low-level vertical wind shear. A few
severe thunderstorms are possible Thursday afternoon and early
evening, when moderate deep-layer bulk shear may coincide with
moderate diurnal destabilization of the warm/moist sector
boundary layer. The occurrence of severe storms will be
contingent on multiple factors, including whether enough cloud
breaks support moderate diurnal destabilization of the boundary
layer, steeper low-level lapse rates, and greater DCAPE. Behind
the front, widespread fair weather is expected as stabilizing
subsidence accompanies the aforementioned surface ridge.
However, isolated showers and thunderstorms are possible behind
the cold front as the passage of additional shortwave troughs
and attendant surface trough axes coincide with at least weak
potential instability in the lowest ~1 km AGL and weak diurnal
destabilization of the boundary layer late Friday morning
through early evening as surface dew points remain near 55F to
60F in the cool sector.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Cool, northwest flow will continue to support cumulus clouds across
the region, with scattered showers east-southeast of Lake Ontario
this afternoon. Ceilings have bounced from MVFR to low end VFR as
cumulus clouds have moved through the terminals. Visibility has
mainly stayed VFR, however a few heavy showers have resulted in a
brief period IFR. Dry air advection and the loss of daytime heating
will put an end to showers this evening, with clouds diminishing in
coverage.

Surface high pressure will build into the region tonight. Light
winds and mostly clear skies will support fog formation and IFR or
below across valley locations across the western Southern Tier and
Finger Lakes region. Today`s rainfall will likely prime some
locations in the Black River Valley for radiation fog as well. Fog
and low stratus will dissipate by mid-morning on Wednesday.

VFR conditions are expected on Wednesday.

Outlook...

Thursday and Friday...Mainly VFR, except brief MVFR/IFR conditions
possible with periods of scattered showers and thunderstorms.

Saturday and Sunday...Dry weather and mainly VFR expected.&&

.MARINE...
Relatively-quiet marine conditions are expected through
Wednesday as a high pressure ridge builds from the western and
central Great Lakes. During Wednesday night, the ridge should
exit E`ward, allow a warm front to sweep NE`ward across Lakes
Erie and Ontario, and cause primarily SE`erly winds around 5 to
15 knots to veer to S`erly to SW`erly and freshen to 10 to
nearly 20 knots. Waves should be mainly 3 feet or less, but
occasional 4 footers are possible. A cold front should sweep
E`ward across eastern Lake Erie and Lake Ontario Thursday
evening through Thursday night and be followed by a ridge
building from the Upper Midwest and vicinity through Friday.
Accordingly, S`erly to SW`erly winds around 10 to nearly 20
knots ahead of the cold front veer to NW`erly and then toward
NE`erly behind the front and ease to around 5 to 10 knots.
Waves of mainly 3 feet or less are expected, but occasional 4
footers are possible ahead of the front and for a short while
behind the front.

The ridge is expected to crest E`ward across the eastern Great
Lakes on Saturday and then begin to exit toward New England this
Sunday. Variable winds around 5 knots on Saturday should be
followed by mainly SE`erly to SW`erly winds around 5 to 10 knots
on Saturday. Waves should be 2 feet or less.

&&

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

&&

$$

DISCUSSION...Jaszka
AVIATION...HSK
MARINE...Jaszka