Forecast Discussion

615
FXUS61 KBUF 240734
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
334 AM EDT Fri Oct 24 2025

.SYNOPSIS...
Lake effect rain will continue east of both lakes today, with
localized heavier rainfall confined to areas east of Lake Ontario,
where up to an additional inch may fall. Outside of lake effect,
expect scattered showers today, especially this afternoon. A few
lighter lake effect showers will linger southeast of the lakes into
the start of the weekend, with high pressure then expected to
provide a mainly dry finish for Sunday, lasting through at least
Tuesday. A cool airmass will remain in place, keeping temperatures a
bit below average through at least the first part of the new work
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The large mid/upper level low that has been responsible for the
unsettled weather through much of the work week will finally be
starting to make a move to the east as we open the period Friday
morning. However, before it does so, yet another vigorous shortwave
will pivot through the base of the mean mid/upper level trough,
crossing just north of Lake Ontario this morning before progressing
east into the Saint Lawrence Valley and northern New England later
this afternoon. This will bring a brief resurgence of the lake
effect intensity, especially east of Lake Ontario. After a brief
lull in the activity in the wake of a surface trough passage, expect
an intensifying lake band off Lake Ontario centering due eastward of
the lake across northern Oswego/southern Jefferson County, east into
western Lewis County...including portions of Tug Hill. Expect a
period of moderate to possibly heavy rain at times across this
region, with the potential for a few rumbles of thunder closer to
the lake through midday/early afternoon. Localized additional
rainfall amounts may reach up to one inch.

Potent shortwave moves east of the area this afternoon, with winds
veering WNW to NW sending lake bands ESE to SE of the lakes. Expect
these bands to also weaken some through the afternoon as deeper mid
and upper level moisture is stripped away behind the shortwave.
Outside of lake effect areas, expect some scattered diurnally driven
showers to develop this afternoon. Temperatures remain a bit on the
chilly side with highs ranging from the mid 40s to low 50s.

Tonight, a cold cyclonic flow remaining overhead combined with
equilibrium levels still around 7-8kft, a cold NW low level flow,
and possibly some additional moisture from upstream lake connections
will maintain weaker lake effect showers southeast of the lakes.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A dynamic longwave troughing pattern will continue to linger across
the Northeast through the weekend. This comes as two embedded
shortwaves, one initially across the ON/QC border and another back
over the western Great Lakes, gradually phase to form a distinct
upper level closed low over southern QC. This upper low will then
drift across New England through Sunday night. Meanwhile, a stout
upper level ridge cresting across ON Province from the Upper Midwest
will cause a strong, expansive 1035mb sfc high to build north across
QC.

This pattern of broad scale subsidence with continued chilly air
aloft (850mb temps dipping to either side of -4C) will result in a
continued stretch of sfc temperatures running below climatological
average and occasional light lake effect rain and/or upslope driven
showers. Between the two days, activity should be more persistent on
Saturday as slightly more mid-level moisture remains in place and
one of the aforementioned shortwaves moves through the region.
Chances for additional light showers will be highest southeast of
both lakes given the prevailing NW flow during this timeframe,
though it will be far from a washout with most areas staying dry
through the day. As drier air advects into the region on a more
northerly flow Sunday, chances for additional rains decrease and
shift more due south of the lakes. By Sunday night a northeasterly
low/mid level flow could direct a few showers over the southwestern
Lake Ontario shoreline, though the rest of the area will remain dry.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Strong sfc high pressure will remain anchored over central Quebec
early next week, with mainly dry but seasonably cool weather
forecast to last through at least Tuesday. There is some potential
for lake effect rains across the southwestern end of Lake Ontario
during this time, which if realized could potentially cross over the
lakeshore and into the Niagara Frontier at times.

Forecast uncertainty in the synoptic scale pattern grows
considerably from Tuesday onwards as a closed low still hanging over
the Northeast interacts with a deep shortwave moving east across the
Tennessee Valley. Long range guidance signals that this will
eventually result in sfc low pressure approaching the region from
the southwest before transitioning into a coastal system, which then
spreads Atlantic-based moisture towards the Great Lakes later in the
week as it climbs up the coast. The GEFS indicates a
weaker/retreating high to our north and the initial sfc low to the
southwest making a closer approach and thus is more aggressive
bringing in some light precip from the west later Tuesday and/or
Wednesday. Will leave NBM`s low-end PoPs to cover this remote
possibility, though the greater chances for rain will come later in
the week once the deeper Atlantic moisture arrives.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
Lake effect rain will continue east of the lakes today, especially
east of Lake Ontario. Expect MVFR CIGS/VSBY within lake effect rain
bands, with local IFR in any heavier showers (KJHW). Outside of main
lake effect activity, expect scattered light showers, especially
this afternoon, with CIGS generally in the marginal MVFR to low VFR
category.

Weaker lake effect showers will will shift southeast of the lakes
later this afternoon and evening with MVFR/low VFR in lake effect
clouds expected to continue for areas south of Lake Ontario, while
clouds are expected to scatter out across the eastern Lake Ontario
region (KART) with winds veering northwesterly taking Lake Ontario
out of play for that area.

Outlook...

Saturday...VFR/MVFR with showers likely, especially southeast of
Lake Ontario and Lake Erie.

Sunday...Mainly VFR with lingering lake showers possible southeast
of Lake Ontario.

Monday through Tuesday...Mainly VFR.

&&

.MARINE...
A seasonably deep low pressure system slowly moving north across
Quebec, gradually diminishing its influence on winds across the
lower Great Lakes.

Westerly flow will remain elevated today with choppy conditions
expected to continue on the lakes, but are expected to remain just
below Small Craft Advisory criteria. Waterspouts will continue to be
possible on Lake Ontario today in and near bands of lake effect rain.

High pressure gradually building over the region through the weekend
will bring a more substantial improvement to wind and wave action,
though lake effect rain showers will remain possible through
Saturday night.

&&

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

&&

$$

SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...PP
LONG TERM...PP
AVIATION...JM
MARINE...Hitchcock/JM/PP

NWS BUF Office Area Forecast Discussion