230
FXUS61 KBUF 180701
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
301 AM EDT Tue Aug 18 2026

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

&&

.KEY MESSAGES...
1.) Dry weather expected today before another round of showers
and thunderstorms overnight tonight into Wednesday.

2.) Primarily dry weather returns Wednesday night through
Friday night.

3.) Periodic showers and thunderstorms possible this weekend
through Monday.

&&

.DISCUSSION...
Key Message 1...Dry weather expected today before another round of
showers and thunderstorms overnight tonight into Wednesday.

A high pressure ridge at the surface and aloft builds from the
central Great Lakes this morning and then crests over our region
this afternoon and early evening. 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. Steam fog will continue to
form in the river and lake valleys of the Western Southern Tier,
Finger Lakes, and Eastern Lake Ontario Region early this morning.
Patchy radiation fog should also form during the same time
period, especially inland from Lakes Erie and Ontario, amidst
lingering low-level moisture from recent rainfall. Fog will
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 this afternoon.

The ridge at the surface and aloft exits E`ward tonight and
allows a warm front to sweep N`ward through Western and Central
NY. Simultaneously, cyclonic W`erly flow aloft becomes established
over our area and embedded shortwave disturbances traverse
Western and Central NY. The cyclonic W`erly flow aloft and
embedded shortwave disturbances will continue to affect our
area on Wednesday, when a cold front should sweep SE`ward
through Western and Central NY. Isolated to scattered showers
and thunderstorms are expected after midnight Tuesday night
through Wednesday as weak to perhaps moderate CAPE, included
elevated CAPE, is released by the following: moist isentropic
ascent along the upper-reaches of the warm front and ahead of
shortwave trough axes; low-level convergence and moist ascent
along the surface warm front, surface cold front, and surface
trough axes attendant to the shortwave troughs. Lows should
reach mainly the 50`s to mid 60`s around daybreak Wednesday
morning and be followed by daytime highs in the 70`s to 80F.

Key Message 2...Primarily dry weather returns Wednesday night
through Friday night.

A ridge should build from the north-central United States and
vicinity Wednesday night through Thursday, crest E`ward across
our area Thursday night into Friday morning, and then exit
E`ward later Friday through Friday night. Primarily fair weather
is expected in Western and Central NY as stabilizing subsidence
accompanies the ridge. However, a few rain showers associated
with moist isentropic ascent along the upper-reaches of the
departing cold front may impact the Western Southern Tier and
southern Finger Lakes Wednesday evening. Overnight lows should
reach the upper 40`s to near 60F around daybreak Thursday as the
cooler air mass overspreads our region behind the cold front
and the building ridge is accompanied by easing surface winds
and considerable clearing. Steam fog is expected in our river
and lake valleys during the late evening hours of Wednesday and
especially during the predawn hours through shortly after
daybreak on Thursday. At least patchy radiation fog should also
form during the same time period, especially inland from Lakes
Erie and Ontario, amidst lingering low-level moisture from
recent rainfall. Highs should reach the 70`s late Thursday
afternoon. Mainly clear sky, light or calm surface winds, and
lower humidity should promote efficient nocturnal cooling
Thursday night and allow lows to reach the mid 40`s to upper
50`s around daybreak Friday. Additional river and lake valley
steam fog is expected, especially during the predawn hours
through shortly after daybreak on Friday morning. Mainly clear
sky and the development of low-level WAA along the backside of
the departing ridge should be accompanied by highs in the mid
70`s to lower 80`s late Friday afternoon and lows in the 50`s to
lower 60`s around daybreak Saturday.

Key Message 3...Periodic showers and thunderstorms possible this
weekend through Monday.

Cyclonic flow aloft and embedded shortwave disturbances affect
Western and Central NY this weekend through Monday. Initially
SW`erly cyclonic flow aloft should veer to NW`erly on Sunday
and remain NW`erly on Monday as the axis of a deep mid/upper-level
trough moves from near the western Great Lakes to near the
NY/New England border between daybreak Saturday and sunset
Monday evening. At the surface, our CWA should reside in net
troughing through the period. A warm front should drift N`ward
through Western and Central NY on Saturday through Saturday
night and be followed by the E`ward passage of a cold front on
Sunday.

Periodic and scattered showers and thunderstorms are expected as
at least weak CAPE, including elevated CAPE, is released by the
following: moist isentropic ascent along the upper-reaches of
the warm front and ahead of shortwave trough axes; low-level
convergence/moist ascent along the surface fronts and surface
trough axes attendant to the shortwave troughs. Near to slightly
above-average highs on Saturday and lows Saturday night should
be followed by primarily below-average air temperatures Sunday
and especially Monday. Behind the cold front, the air mass may
be cold and moist enough to support the development of at least
isolated lake-effect rain showers and thunderstorms over and
generally east or southeast of the ~23C to ~24C eastern Great
Lakes Sunday night into Monday.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
High pressure will provide dry weather and light winds through the
entire TAF period. Other than areas of MVFR/IFR VSBY in patchy fog
for the remainder of the overnight through an hour or two after
daybreak owed to lingering low level moisture, VFR flight conditions
will be predominant through the period. Fog may be more widespread
than just typical river valley fog, with fairly widespread IFR VSBY
possible across many areas inland from the immediate Great Lakes
shorelines from about 07Z through 12Z. KART (recent rains) and KJHW
(higher terrain) look to be the most favorable areas to be impacted
by thicker fog.

As noted above, any fog will dissipate by mid morning, leaving VFR
to prevail as high pressure remains over the eastern Great Lakes.

Outlook...

Tuesday Night through Wednesday...Areas of MVFR/local IFR with
showers and a few scattered thunderstorms.

Wednesday Night through Friday...Dry weather and mainly VFR,
although localized fog with IFR VSBY in/near river/lake valleys is
possible around daybreak on Thursday and Friday.

Saturday...Mainly VFR with a few scattered showers possible.

&&

.MARINE...
Wind speeds around 5 to 15 knots and waves of 3 feet or less are
expected during the rest of this week. A high pressure ridge
builds from the central Great Lakes this morning and will be
accompanied by primarily N`erly winds. During this afternoon
through evening, the ridge axis moves E`ward across eastern Lake
Erie and Lake Ontario, and causes winds to back to SW`erly. On
Wednesday, a cold front will sweep SE`ward across eastern Lake
Erie and Lake Ontario and cause SW`erly winds to veer to NW`erly
to N`erly. Behind the cold front, a ridge builds from the Upper
Midwest and western Great Lakes through Friday and causes winds
to become variable in direction. The ridge should exit E`ward
from the lakes Friday night through Saturday and allow a warm
front to drift N`ward through the area. The warm front passage
should cause mainly E`erly to SE`erly winds to veer to S`erly to
SW`erly.

&&

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

&&

$$

DISCUSSION...Jaszka
AVIATION...JM
MARINE...Jaszka