Forecast Discussion

655
FXUS61 KBUF 042245
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
645 PM EDT Tue Aug 4 2026

.WHAT HAS CHANGED...
Only minor adjustments with this update.

&&

.KEY MESSAGES...
1) Warmth and humidity are expected across the region for the
second half of the week.

2) The chance for showers and thunderstorms increases day to day
through the end of the week. Heavy downpours are possible Thursday
and Friday.

&&

.DISCUSSION...
Key Message 1...Warmth and humidity are expected across the
region for the second half of the week.

An upper level ridge and surface high pressure will continue to
support seasonal weather and low humidity across the region today.
These two features will move east off the east coast tonight as
fair weather persists in Western and Central NY. Efficient
nocturnal cooling amidst clear to mainly clear sky and weak
surface winds should allow steam fog to form in the river
valleys of the Western Southern Tier and along at least the
southern-half of the Genesee River during the predawn hours of
Wednesday morning. Fog will dissipate shortly after daybreak,
following the onset of diurnal convective mixing of the boundary
layer. A southwest flow will begin to deepen across the region
Wednesday. A feed of warm air and moisture will filter across
the region through the end of the week. High temperatures will
range from the low to mid 80s. Heat index values are expected to
rise into the upper 80s to possibly 90 across the lake plains
including the Finger Lakes region.

Key Message 2...The chance for showers and thunderstorms increases
day to day through the end of the week. Heavy downpours are possible
Thursday and Friday.

An upper level trough will move across the Northern Plains to the
Central Great Lakes region through the end of the week. Multiple
shortwave troughs are expected to move within the trough and support
periods of showers and thunderstorms. Warm, moist air will return to
the region Wednesday, and diurnally driven scattered convection is
expected to develop from the western Southern Tier to the Rochester
area during peak heating. Dry air and subsidence should limit rain
chances across the eastern Lake Ontario region. While shower chances
will linger Wednesday night, another round of diurnally driven
convection is expected Thursday. A shortwave wave and approaching
front may produce better coverage of showers and thunderstorms. The
flow remains weak, so the severe threat is low, however with PWATS
remaining above the 90th percentile, heavy rain is possible.

A slow moving cold front is expected to reach the region Friday.
Another round of scattered to numerous showers and thunderstorms are
expected across the region with heavy rain being the main hazard.
There is uncertainty in the timing and intensity of thunderstorms
and therefore the risk for flooding is low.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
At the surface, a high pressure ridge continues to affect
Western and Central NY as the ridge exits slowly toward New
England through 00Z/Thurs. Our regional surface winds trend
light and variable through ~13Z/Wed and S`erly to SW`erly
around 5 to 10 knots from ~13Z/Wed through 00Z/Thurs. However,
Lake Erie and Lake Ontario lake breezes are expected late Wed
morning through early evening and will impact locations within
several miles of both lakes, including KBUF, KIAG, and KART.

Primarily fair weather and VFR are expected through the TAF
period. However, localized and shallow steam fog is expected
during the predawn hours of Wed morning through shortly after
daybreak in the river valleys of the Western Southern Tier and
along roughly the southern-half of the Genesee River. Winds
around 10 to 15 knots at about 1kft to 2kft AGL should keep
this fog shallow and prevent it from impacting KJHW. Isolated
to scattered showers and thunderstorms should develop along the
Lake Erie lake breeze front, the Lake Erie/Lake Ontario lake
breeze convergence zone in vicinity of the Niagara Escarpment,
and via daytime heating across western NY and the Genesee
Valley from ~19Z/Wed through 00Z/Thurs. Brief MVFR to LIFR and
brief/erratic surface wind gusts up to 30 to 40 knots are
expected with these showers and especially storms.

Outlook...

Wednesday Night through Sunday...Periodic showers and thunderstorms
with MVFR or worse conditions are expected, especially each
afternoon through early evening.

&&

.MARINE...
High pressure will reside across the lower Great Lakes through
tonight and support light winds and waves. The chance for
showers and thunderstorms increases the second half of the week.
No small craft headlines are expected through the rest of the
week.

&&

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

&&

$$

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

NWS BUF Office Area Forecast Discussion