776
FXUS61 KBUF 150720
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
320 AM EDT Sat Aug 15 2026

.WHAT HAS CHANGED...
Only minor changes with this forecast update.

&&

.KEY MESSAGES...
1.) Mainly dry weather continues through tonight.

2.) Scattered showers and thunderstorms are expected Sunday
into Sunday night. Isolated showers and thunderstorms are
possible this Monday.

3.) Dry weather is expected this Monday night through Tuesday.

&&

.DISCUSSION...
Key Message 1...Mainly dry weather continues through tonight.

NW`erly flow aloft and stabilizing subsidence affect our region
today as a surface high pressure ridge affects the eastern
Great Lakes and vicinity, while the ridge aloft builds from the
Upper Midwest and vicinity. As a result, dry weather is expected
in all of Western and Central NY. Clear to partly cloudy sky
and weak or calm surface winds will contribute to lows reaching
the mid 40`s to near 60F in the Eastern Lake Ontario Region and
mainly the 50`s to lower 60`s elsewhere in our CWA around
daybreak this morning. The coolest lows are expected in Lewis
County, especially the Black River Valley, where efficient
radiational cooling should be complemented by cool air drainage
from adjacent higher terrain. Sufficient nocturnal cooling and
low-level moisture will result in patchy radiation fog and
steam fog in the river and lake valleys of the Western Southern
Tier, Finger Lakes, and Eastern Lake Ontario Region through
shortly after daybreak. High temperatures late this afternoon
are expected to reach the 70`s in the Eastern Lake Ontario
Region and the mid 70`s to mid 80`s elsewhere.

The ridge at the surface and aloft begins to exit E`ward tonight
as a shortwave trough approaches from the central Great Lakes
and a surface warm front approaches from the OH Valley and
vicinity. Moist isentropic ascent ahead of the shortwave trough
axis and along the upper-reaches of the warm front should
release weak, yet sufficient elevated CAPE to allow isolated
showers and thunderstorms to impact the Western Southern Tier
during the predawn hours of Sunday morning. Fair weather is
expected to persist elsewhere in our CWA. Lows should reach the
mid 40`s to lower 60`s in the Eastern Lake Ontario Region and
mainly the lower to mid 60`s elsewhere. Readings should begin to
moderate toward daybreak, especially in Western NY and the
Finger Lakes, as low-level WAA strengthens ahead of the warm
front.

Key Message 2...Scattered showers and thunderstorms are
expected Sunday into Sunday night. Isolated showers and
thunderstorms are possible this Monday.

Cyclonic W`erly to NW`erly flow aloft and embedded shortwave
troughs will impact Western and Central NY on Sunday through
Monday. At the surface, a low should wobble SE`ward from the
northern Great Lakes to near southern New England and Long
Island. This low track should allow the surface warm front to
drift NE`ward through our CWA Sunday morning through evening,
which will usher-in a warmer and more humid air mass originating
over the Gulf, and be followed by the E`ward passage of a
surface cold front Sunday evening through Monday morning. Behind
the cold front, a surface ridge attempts to build from the
Upper Midwest and vicinity.

Scattered showers and thunderstorms are expected along and ahead
of the surface warm and cold fronts as weak to perhaps moderate
CAPE, including elevated CAPE, amidst moderate to perhaps
strong deep-layer bulk shear, is released by the following:
moist isentropic ascent along the upper-reaches of the warm
front, low-level convergence/moist ascent along the surface warm
and cold fronts, and as downshear gust fronts interact favorably
with low-level vertical wind shear. Severe storms still appear
possible Sunday afternoon into the evening, but their occurrence
will be contingent on multiple factors, including the degree of
diurnal destabilization of the warm/moist sector boundary layer.
Sufficient diurnal destabilization for severe storm occurrence
remains questionable given the expectation of abundant cloud
cover on Sunday. Behind the cold front, isolated rain showers
should occur Sunday night into Monday since subtle shortwave
troughs and attendant surface trough axes will traverse Western
and Central NY generally from west to east. Low-level
convergence and moist ascent along the surface trough axes
should release at least weak potential instability in the lowest
~1 km AGL. A few thunderstorms are possible Monday afternoon and
evening, before sunset, when the same lifting mechanisms may
release weak boundary layer CAPE stemming from daytime warming.
Compared to 24-hours ago, the potential for lake-effect rain
showers over and generally southeast of Lakes Erie and Ontario
overnight Sunday night into Monday appears to be marginal since
low-level CAA may be slightly weaker than projected by previous
cycles of NWP models. We will continue to monitor the potential
for lake-effect rain.

High temperatures are forecast to reach the 70`s to lower 80`s
Sunday afternoon. Lows should reach mainly the upper 50`s to
mid 60`s around daybreak Monday. Late afternoon highs should
reach the 70`s to lower 80`s on Monday, behind the weak cold
front.

Key Message 3...Dry weather is expected this Monday night
through Tuesday.

The above-mentioned high pressure ridge at the surface and
aloft should build from the western Great Lakes and vicinity
Monday night through Tuesday. Stabilizing subsidence
accompanying the ridge is expected to promote dry weather.
Considerable clearing and weak or calm surface winds
accompanying the ridge should contribute to lows reaching the
50`s to lower 60`s around daybreak Tuesday. Steam fog should
form in the river and lake valleys of the Western Southern Tier,
Finger Lakes, and Eastern Lake Ontario Region during the
predawn hours of Tuesday morning and then dissipate via the
onset of diurnal convective mixing of the boundary layer shortly
after daybreak. Highs are forecast to reach the 70`s to lower
80`s late Tuesday afternoon.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Some patchy fog will develop overnight through early Saturday
morning with local IFR, mainly across the valleys of the Southern
Tier, Finger Lakes, and North Country. Otherwise, VFR will prevail
through early Saturday morning with a few areas of mid/high clouds
crossing the region.

The fog will burn off by mid morning, with VFR prevailing areawide
through the rest of Saturday with a few diurnal cumulus and areas of
cirrus.

Outlook...

Sunday through Sunday night...Mainly VFR Sunday morning with a
chance of showers, then areas of MVFR/local IFR with showers and
scattered thunderstorms Sunday afternoon through Sunday night.

Monday...Mainly VFR with a chance of a few spotty showers.

Monday Night through Tuesday...Mainly VFR. Late night/early morning
river valley fog with local IFR across the Southern Tier.

Wednesday...Mainly VFR with a chance of a shower or thunderstorm
late.

&&

.MARINE...
Overall, light winds over the lakes today with high pressure
building across the lower Great Lakes region keeping waves 2 feet or
less. Winds will transition from northerly to easterly during the
overnight period headed into Saturday. As high pressure continues to
slide eastward, pressure gradients will increase Saturday evening
ahead of the next frontal passage with showers and storms into
Sunday. Gusty winds and larger waves may be possible in the vicinity
of storms. High pressure will build back into the region early next
week that will calm winds and waves.

&&

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

&&

$$

DISCUSSION...Jaszka
AVIATION...Hitchcock
MARINE...Brothers