219
FXUS61 KBUF 092351
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
651 PM EST Tue Dec 9 2025

.SYNOPSIS...
Lake effect snow will briefly develop northeast of the lakes this
evening, with a few inches of accumulation locally across the
Niagara Frontier off Lake Erie and Thousand Islands region off Lake
Ontario. Low pressure will then pass just north of the area
Wednesday. Widespread snow will develop ahead of the system late
tonight and continue Wednesday, with the lower elevations of Western
and Central NY likely changing to rain during the day as
temperatures warm above freezing. Much colder air will then move
back into the region Wednesday night through Thursday night, with
accumulating lake effect snow southeast of the lakes.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
A weakening trough will cross north-central NY early evening, with a
brief period of snow crossing north-central from west to east.

Following the trough, there will be a brief window of marginally
favorable lake effect setup northeast of the lakes this evening. Off
Lake Erie, a band of snow will develop mainly across Niagara County
and some of the Buffalo Northtowns with 1-3" of accumulation
possible. This will be short lived, with falling inversion heights
and warm advection shutting down the lake effect by around midnight.
Off Lake Ontario, a band of snow will develop mainly in Canada,
although it may occasionally clip the Thousand Islands region with a
few inches of snow overnight.

A strong clipper low will then move from southern lower Michigan
Wednesday morning to the Saint Lawrence Valley Wednesday night.
Widespread warm advection/isentropic upglide driven snow will break
out ahead of the system late tonight and continue through Wednesday
morning. Precipitation type will stay all snow across the high
terrain and the North Country, but lower elevations will mix with,
or change to rain from mid morning through mid to late afternoon
Wednesday as the boundary layer warms above freezing and surface
temps rise into the mid to upper 30s. Wednesday night, precip will
change back to all snow and evolve into more of an upslope, lake
enhanced regime overnight behind the system.

As far as accumulations go, from this evening through late Wednesday
night expect 8-14" across the Tug Hill Plateau and western foothills
of the Adirondacks, with 3-6" across the surrounding lower
elevations east of Lake Ontario. Across Western NY, expect 4-8" for
the higher terrain of the Boston Hills and western Southern Tier,
with 2-5" across the Niagara Frontier.

Winds, there will be two periods of gusty winds. The first will be
later this afternoon and evening northeast of Lake Erie, with peak
gusts in the 30-40 mph range. The second period of strong winds will
be Wednesday afternoon, again gusting in the 30-40 mph range
northeast of Lake Erie.

&&

.SHORT TERM /THURSDAY THROUGH WEDNESDAY NIGHT/...
A deepening closed low will have its 700-500mb core centered just
north of the forecast area over the southern ON/QC border Thursday
morning. Through Thursday night this system will slowly translate
east to the Canadian Maritimes, leaving broad cyclonic WNW flow
across the eastern Great Lakes. Post-frontal CAA will bring 850H
temps back down to either side of -16C as deeper synoptic moisture
circulates back around the low. This will allow moderate to heavy
lake effect snow to continue southeast of both lakes, with breezy
winds creating areas of blowing and drifting snow. Outside the main
lake effect/upslope areas, occasional passing snow showers will
bring very minor snowfall to the rest of the area, generally an inch
or less.

Off Lake Erie...A subtle backing of the low/mid level flow will
direct the heaviest additional snowfall though Thursday night along
or just south of the Erie/Cattaraugus border. An upstream
connection to Lake Huron may support an additional localized 7-9" in
this area, while upslope flow may add 4-6" to the totals across the
Chautauqua Ridge. Small ripples in the flow will cause the main band
to occasionally clip surrounding areas though overall totals should
be comparatively lower. Snows should diminish in intensity Thursday
night as drier air and (to a lesser degree) shear increase ahead of
an approaching ridge off to the west.

Off Lake Ontario...The main focus for heavier snow in this timeframe
for our CWA is expected to be in the corridor from eastern Wayne to
extreme southern Oswego across Northern Cayuga. An upstream
connection to Georgian Bay should yield similar magnitude snows in
this area with an additional 7-9" forecast. Could see this upper end
of this range increase depending on how much moisture lingers across
the eastern end of the lake Thursday night; the GFS/NAM
indicate an intrusion of dry air which strips the DGZ of
moisture, as opposed to the Canadian models which keep the edge
of the deeper synoptic moisture hanging over the lake for longer.
Have hedged above continuity but below the bullish CMCReg for
QPF/SnowAmts until the picture comes into better focus.
Otherwise, the edge of the lake snows with added orographic lift
will add up to 4-6" up on and around the eastern Tug Hill south
of Watertown.

As a surface-850mb ridge continues to encroach on the area from the
central Great Lakes Friday, diminishing lake snows will likely climb
a bit further northward. These may reach the Buffalo and Watertown
metros by the afternoon and bring some nuisance snow for the evening
commute, though there remains uncertainty in band strength by this
point.

Otherwise...In contrast to Wednesday`s brief warmup, temperatures
this period will return to running some 10-15 degrees below average.
The blustery winds on Thursday will create wind chills in the teens
and single digits, with widespread single digits Thursday night.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Little in terms of reprieve from the active pattern this weekend and
early next week. A flattening ridge of high pressure cresting east
of the Great Lakes Friday night will be quickly followed by the next
deep upper level trough which will dig southeast and become
increasingly negatively tilted over the Northeast through the
weekend. This will result in at least one more round of synoptic
snow for the area sometime between late Friday night and Saturday,
with a very deep cold airmass wrapping around the main low causing
additional lake effect snow to continue downwind of the lakes into
at least early next week. Sfc temps will in all likelihood continue
to run well below normal, especially Sunday and Monday, though long
range guidance is in fairly good agreement on some degree of warming
with the lake response weakening Tuesday onwards. Still a high
amount of uncertainty in the details and plenty of weather to sort
out between now and this weekend, though long range ensembles favor
an initial westerly flow becoming increasingly northwesterly in the
second half of the weekend.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
A weakening trough will cross northern NY this evening, producing a
brief period of light snow east of Lake Ontario with occasional IFR
VSBY. Lake effect snow will then develop this evening northeast of
Lake Erie near KIAG, and northeast of Lake Ontario north of KART
with local IFR conditions. The lake effect will not last long,
ending overnight.

A strong clipper low will then pass just north of the area
Wednesday. Widespread snow will develop from west to east across the
region late tonight through early Wednesday morning, with widespread
IFR VSBY and MVFR/IFR CIGS. The snow will mix with, or change to
rain for lower elevations from late morning through the afternoon,
while staying all snow across higher terrain. IFR VSBY will continue
in the snow, with improvement to MVFR/VFR in areas that change to
rain. A cold front will move across the region late Wednesday
afternoon through evening. Lake enhancement will allow snow to
blossom east of the Lakes while widespread MVFR/IFR conditions. A
northwest flow with lake effect snow bands will continue southeast
of the Lakes Wednesday night.

Gusty winds will develop northeast of Lake Erie evening, and again
Wednesday afternoon, with gusts in the 30-35 knot range during both
periods at KBUF and KIAG.

Outlook...

Wednesday night...Lower elevation rain/snow changing back to all
snow, with lake effect snow developing southeast of the lakes
overnight. IFR in areas of snow.

Thursday through Thursday night...VFR/MVFR with scattered light snow
showers. Areas of heavier lake effect snow with IFR/LIFR southeast
of the lakes. Terminals most likely impacted will be KJHW and KROC.

Friday and Saturday...MVFR/IFR east of the lakes with snow showers
likely. MVFR/VFR outside the main lake effect areas.

Sunday...MVFR/IFR with widespread snow likely.

&&

.MARINE...
A deepening area of low pressure will pass by just north of Lake
Erie, though very close to Lake Ontario such that the strongest wind
fields with this second storm system will maintain gales to just
Lake Erie.

Behind this second low, a persistent west to northwesterly flow
below gale force will ensue Wednesday night and through much of the
remainder of the week with small craft conditions on both Lakes
right through the week...if not through the weekend.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory until 10 AM EST Wednesday for NYZ001-
     002-010-011.
     Winter Storm Watch from late Wednesday night through Friday
     morning for NYZ004-005.
     Winter Storm Warning from 4 AM Wednesday to 1 PM EST Thursday
     for NYZ006>008.
     Winter Weather Advisory from 1 AM Wednesday to 4 AM EST Friday
     for NYZ012-019>021-085.
MARINE...Small Craft Advisory until 4 AM EST Thursday for LEZ020.
         Small Craft Advisory until 4 AM EST Wednesday for LEZ040-
         041.
         Gale Warning from 4 AM to 7 PM EST Wednesday for LEZ040-
         041.
         Small Craft Advisory until 10 AM EST Friday for
         LOZ042.
         Small Craft Advisory until 6 PM EST Saturday for
         LOZ043>045.

&&

$$

SYNOPSIS...Hitchcock
NEAR TERM...Hitchcock/HSK
SHORT TERM...PP
LONG TERM...PP
AVIATION...Hitchcock/HSK
MARINE...HSK/Thomas