191
FXUS61 KBUF 300028
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
828 PM EDT Wed Jul 29 2026

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

&&

.KEY MESSAGES...
1) Heavy rain and isolated areas of flash flooding are possible
across north central NY through early tonight.

2) Increasingly drier conditions return for the end of the work
week.

&&

.DISCUSSION...
Key Message 1...Heavy rain and isolated areas of flash flooding are
possible across north central NY through early tonight.

An upper level low will remain nearly stationary over western New
England through tonight, with an occluded and slow moving surface
low slowly moving up the southern New England coast. A pronounced
trough will linger NE of the surface low up through the St. Lawrence
valley, which will provide the focus for shower and thunderstorm
development this afternoon and evening. Eventually, this trough will
weaken as is slides southwestward towards the Finger Lakes tonight.

Diurnal heating will enhance shower and thunderstorm development
through this evening, while high PWATs (1.5-1.75") and a tall warm
cloud layer will promote efficient heavy downpours. The main area of
concern will be from the eastern Finger Lakes up to the St. Lawrence
Valley. Here an addtional 1-2" of rain will be possible, with
isolated pockets of up to 4" of rain possible, which will bring the
potential for isolated flash flooding.

Rain showers and thunderstorms will decrease in coverage late this
evening with loss of heating, and precipitation chances will slowly
fall overnight.

Key Message 2...Increasingly drier conditions return for the end of
the work week.

Tomorrow and Friday, the low pressure system at the surface and
aloft will exit gradually NE`ward toward the Canadian Maritimes.
Simultaneously, the aforementioned surface ridge and the portion of
the ridge aloft will continue to build from the western Great Lakes
and vicinity so that by late Friday, the surface ridge axis should
become located near Long Island and Lake Champlain. While lingering
low-level moisture, renewed diurnal heating, and weak boundary layer
destabilization may support self-destructive sunshine in the form of
isolated to scattered shower and isolated thunderstorm development
roughly along and east of the Genesee River Valley on Thursday,
stabilizing subsidence accompanying the building ridge will yield
fair weather CWA-wide late Thursday evening through Friday. Given
the projected weather pattern evolution at the surface and aloft,
weak low-level CAA through Thursday night is expected to transition
to weak low-level WAA on the synoptic scale by Friday.

Late afternoon highs tomorrow should reach the 70`s to 80F.
Considerable clearing of sky, lower humidity at/near the
surface, and weak surface winds should permit efficient
radiational cooling and allow lows to reach mainly the 50`s to
lower 60`s around daybreak Friday. River valley steam fog is
expected around daybreak in the Western Southern Tier, Finger
Lakes, and the Saint Lawrence and Black River Valleys. With the
departure of the low aloft and its associated cool pool, high
temperatures should recover to seasonable levels (upper 70`s to
lower 80`s) areawide by Friday.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Center of surface low pressure will slowly weaken while continuing
to spin across southern New England tonight, before continuing to
weaken further on Thursday while finally starting to pull east off
the New England coast. Moisture continues to wrap in around this
system with the western edge of the main cloud deck just east of a
line drawn from KBUF to KJHW this evening, with not much eastward
progression of the western fringe through the overnight hours. This
will result in VFR flight conditions for KIAG/KBUF/KJHW through the
TAF period. Further east, deeper moisture ramps up quickly with VFR
low level decks found at KROC, deteriorating to MVFR/higher terrain
IFR east of Lake Ontario (KART) accompanied by periodic showers. Not
expecting much change in conditions through the overnight, except
for a lessening in shower coverage, and another slug of deeper
moisture pivoting around the low that may bring MVFR flight
conditions back further west into the Genesee Valley (KROC) and
Finger Lakes region again later tonight into Thursday morning.

Widespread VFR flight conditions expected across far western NY to
start the day Thursday, while MVFR hangs on from the Genesee Valley
eastward through the morning hours. Low pressure over southern New
England to start Thursday will weaken while also starting to make a
move to the east. At the same time, high pressure will be building
into the Ohio Valley from the west. The combination of deeper
moisture associated with the low pulling east and drier
air/subsidence with the high moving in from the west will allow for
a return to VFR at all sites by mid to late afternoon, with possibly
a few lingering scattered light showers or a thunderstorm east of
Lake Ontario.

Outlook...

Friday through Saturday...VFR.

Saturday night and Sunday...MVFR/VFR. Showers likely with a chance
of a few thunderstorms.

Monday...Mainly VFR, with scattered showers and thunderstorms in the
afternoon along lake breeze boundaries.

&&

.MARINE...
Center of surface low pressure will slowly weaken while continuing
to spin across southern New England tonight, before continuing to
weaken further on Thursday and finally starting to pull east off the
New England coast. This will keep a northerly flow in place on the
Lakes, with choppy conditions persisting along the southern shores
on both lakes into Thursday morning, with winds around 10 to 15
knots.

Winds will begin to diminish later Thursday morning through the
afternoon as high pressure moves east into the Ohio Valley weakening
the pressure gradient over the lakes. The diminishing synoptic flow
will then allow weak lake breeze circulations to develop Thursday
afternoon.

&&

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

&&

$$

DISCUSSION...SGK
AVIATION...JM
MARINE...JM