Forecast Discussion

642
FXUS61 KBUF 130635
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
235 AM EDT Sun Sep 13 2026

.WHAT HAS CHANGED...
Minor changes to the forecast with this update.

&&

.KEY MESSAGES...
1) Warm and humid conditions will continue today, with showers
and scattered thunderstorms through this evening.

2) Brief cooldown Monday through early Tuesday morning, then
trending warmer and unsettled through the middle of the week.

&&

.DISCUSSION...
KEY MESSAGE 1...Warm and humid conditions will continue today,
with showers and scattered thunderstorms through this evening.

GOES water vapor imagery shows a southern stream shortwave trough
across Pennsylvania early this morning. An axis of PWATS over 1.5
inches within a region of strong moisture transport has moved east
of the forecast area. Steady showers have exited the Southern Tier,
though showers will continue across the Finger Lakes and north-
central NY early this morning. A very moist airmass will remain
across the forecast area, with dewpoints remain in the mid to upper
60s. Patchy fog and stratus are expected through daybreak.

A surface trough is expected to move across the region this morning,
and a few showers can`t be ruled out due to weak low-level
convergence. A strong northern stream trough will move into the
Great Lakes region today with an associated cold front approaching
the forecast area before passing through this evening. Instability
will develop across most of the region today. A southwest wind will
likely shadow areas downwind of the Lakes, keeping conditions mostly
dry there. Showers and scattered thunderstorms are expected to
develop along and inland from lakebreeze. Forecast soundings
suggest increasing mid-level winds and steepening mid-level lapse
rates ahead of the cold front. Isolated severe thunderstorms are
possible with damaging winds and large hail as the primary hazards.
The main area of concern is the inland areas of the western Southern
Tier extending to the Finger Lakes region. Most showers and
thunderstorms will be progressive, though brief heavy downpours
are possible. Some HREF members show a line of heavy showers
and thunderstorms developing across the Niagara Pennsiula to the
Niagara Frontier this afternoon. A narrow region of localized
heavy rain and an isolated severe thunderstorm are possible.

The cold front and the leading edge of the trough will move across
the region this evening. A ribbon of mid-level moisture will
maintain chances for showers. Cold air advection and drier air will
filter into the region tonight, with 850mb temperatures tumbling
through Monday morning.

KEY MESSAGE 2...Brief cooldown Monday through early Tuesday morning,
then trending warmer and unsettled through the middle of the week.

Drier and much cooler weather will settle across the region Monday
through Monday night. Northwest flow and 850mb temperatures
bottoming out to as low as +3C will result in below normal
temperatures. High temperatures will range from the mid to upper
60s, to the lower 60s across the higher terrain. Surface high
pressure will move across the region Monday night. Temperatures will
fall into the 40s, with the potential for locations across the
Southern Tier valleys and Tug Hill region to reach the upper 30s.
Patchy frost can`t be ruled out across portions of Lewis county
Monday night.

An upper level ridge will build briefly across the Great Lakes
region Monday night through Tuesday before settling south of the
region through mid-week. Warmer weather will return to the region as
a frontal boundary with increasing moisture stalls near the forecast
area. This may bring periods of showers and thunderstorms through
Thursday.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Widespread low clouds are expected with ceilings varying between
MVFR across the lower elevations to IFR/LIFR across the higher
terrain this morning. An area of showers will exit north-central
NY early this morning, mainly staying east of KART.

A warm and humid airmass will remain across the region today.
Lower ceilings will linger through the morning, before improving
to VFR this afternoon. Another round of showers and scattered
thunderstorms is expected across inland locations this
afternoon into this evening. Brief downpours and MVFR to LIFR
are possible within the showers and especially thunderstorms.
Isolated severe thunderstorms are possible, mainly from the
inland areas of the western Southern Tier to the Finger Lakes
region this afternoon. A brief/erratic surface wind gusts up to
30 to 50 knots can`t be ruled out.

A cold front will move across the region tonight. MVFR/IFR
ceilings are expected as northwest flow builds into the region.
Showers are possible in the evening, with dry conditions late
tonight through Monday.

Outlook...

Monday through Monday night...Dry weather expected. Areas of
MVFR CIGS with lake-effect clouds Monday morning, then
improving to VFR.

Tuesday...Dry weather expected. Localized MVFR to LIFR in early
morning valley fog across the Western Southern Tier. Otherwise
VFR expected.

Tuesday night through Thursday...Periods of showers and
thunderstorms with MVFR or worse conditions expected.

&&

.MARINE...
Low pressure will move slowly east from Hudson Bay east across
Quebec today, with a trailing cold front crossing the lower
Great Lakes this evening. Southerly winds will gradually veer
to the southwest and west through the day.

Northwest winds will increase in the wake of the cold front late
tonight through Monday, likely bringing Small Craft Advisory
conditions to portions of the lower Great Lakes.

&&

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

&&

$$

DISCUSSION...HSK
AVIATION...AR/HSK
MARINE...Hitchcock/HSK

NWS BUF Office Area Forecast Discussion