WX in text

336
FXUS61 KBUF 121154
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
654 AM EST Fri Dec 12 2025

.SYNOPSIS...
Impactful lake snows will move north into Oswego County today off
Lake Ontario with lighter snows further inland, while the remainder
of the area sees a brief break in the active weather. Lake effect
snow will develop late tonight toward Niagara County ahead of a
strong cold front, with a quick few inches of snow possible
northeast of Lakes Erie and Ontario Saturday as the front crosses
the region. Much colder air moves back into the area Saturday night
and Sunday behind the cold front with heavy lake effect snows
possible east of both lakes.

&&

.NEAR TERM /THROUGH TONIGHT/...
Main story today will be a band of moderate to at times heavy lake
effect snow that will develop east of Lake Ontario, mainly across
Oswego County, but possibly reaching into far southwestern Lewis
County at times. Otherwise, the remainder of the area will get a
well deserved brief break in the active weather. Lake effect snow
details follow just below...

Off Lake Erie...

Westerly flow will begin to back to southwesterly later today with
little activity off the lake through the daylight hours. However, as
southwesterly flow aligns down the long axis of the lake very late
today, may see a few light snow showers develop northeast of the
lake for the evening hours with only very minor accumulations
expected. Later tonight, winds back even further to south-southwest
ahead of an approaching strong cold front. Deeper moisture pushing
into the area combined with increasing surface convergence ahead of
the front will lead to a band of lake effect snow developing north-
northeast of the lake, initially across western Niagara County,
possibly sagging as far south as northern Erie County very late
tonight with a couple inches of accumulation possible across these
areas by daybreak Saturday.

Off Lake Ontario...

Very light lake effect snow showers and flurries southeast of the
Lake Ontario across far northeastern Wayne, northern Cayuga and
southern Oswego counties will continue into this morning, while
slowly working their way further north into Oswego County. Later
this morning, winds will realign out of the west down the long axis
of the lake, allowing a band of lake effect snow to redevelop and
strengthen east of the lake into Oswego County, possibly stretching
into southwestern Lewis County at times. An upstream connection to
Georgian Bay looks to develop as well, further boosting confidence
for a well-organized band to regenerate. Flow will then back to
southwest later this evening before shifting to south-southwest and
eventually south by daybreak Saturday. This will not only cause the
band to shift northward from late this evening through the second
half of the night, but weaken it at the same time as the band sweeps
from south to north through Jefferson County. As for accumulations,
expecting 6-10 inches in the most persistent snows across central
and northern Oswego County through this evening where a Lake Effect
Snow Warning remains in effect. This warning will remain in effect
through Sunday afternoon to encompass a second event that is
expected to begin Saturday afternoon. See the Short Term section of
this discussion for more details. Otherwise, increasing shear and
decreasing fetch off the lake will rapidly weaken the band as it
lifts north through Jefferson County tonight with 2-3 inches
possible across southern Jefferson County as the band makes its
initial move north, then an inch or less through the northern half
of the county as what`s left of the band moves all the way into the
Saint Lawrence Valley by very late tonight.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A mid level closed low will advance from near the north shore of
Lake Superior Saturday morning to the eastern Great Lakes by Sunday,
sharpening and opening up into a trough axis with time. This system
will deliver a fresh batch of cold air to the eastern Great Lakes,
supporting the next round of heavy lake effect snow east of the
lakes.

Outside of lake effect areas, a baroclinic wave will move from the
Ohio Valley to southern New England on the southern flank of the
digging trough. This feature may produce some widespread (non-lake
effect) light snow late Saturday afternoon through Saturday night,
especially across the Southern Tier and Finger Lakes with minor
accumulations.

The lake effect snow potential will increase again as cold air
deepens. Latest 00Z guidance continues to suggest the best setup
will be off Lake Ontario, especially Saturday night through Sunday
morning. Lake induced equilibrium levels will rise to near 15K feet,
peaking Sunday morning as the pool of coldest air aloft and best
synoptic scale moisture and forcing move over the eastern Great
Lakes.

Off Lake Erie...

A band of lake enhanced snow along the arctic cold front will be
northeast of the lake near the Buffalo Metro area and Niagara
Frontier early in the morning. This band of snow will move quickly
south into the Southern Tier by midday as boundary layer flow veers
more westerly. The lake effect setup becomes more complicated for
Saturday night as the weak baroclinic wave passes by to the south of
Lake Erie, which will likely introduce shear into the boundary layer
and disrupt banding structures. Flow will then become northwest on
Sunday with lake enhanced upslope snow across the higher terrain,
and there will likely be an upstream connection to Lake Huron that
will locally enhance snowfall. The northwest flow lake snow
continues through Sunday evening before drier air, shear, and
anticyclonic flow weakens lake effect overnight.

As far as accumulations go, the setup is not as favorable as Lake
Ontario will be, but nonetheless, snow totals will add up over the
36-48 hour period and likely approach low end watch/warning
criteria across the higher terrain of the western Southern Tier and
Boston Hills. With this in mind, we have issued a Winter Storm Watch
for lake effect snow for southern Erie, Chautauqua, and Cattaraugus
counties from Saturday through Sunday night. The initial phase of
this event may bring advisory worthy snow amounts to portions of the
Niagara Frontier and Buffalo Metro area Saturday morning before
quickly moving south.

Off Lake Ontario...

A band of lake enhanced snow along the arctic front will intensify
northeast of the lake over Canada Saturday morning, then swing
southeast across Jefferson County Saturday afternoon before focusing
on the Tug Hill region by Saturday evening. The band of snow will
then intensify Saturday night near the Oswego/Jefferson county
border and western Tug Hill Plateau. A strong convergence signature
and ideal cloud microphysics should allow this band to become quite
strong, with 2-3+" per hour snowfall rates likely. This intense band
will then move south across Oswego County Sunday morning, and settle
into northern Cayuga and far northeast Wayne County for a time
Sunday. The band will still be quite intense, with 2-3+" per hour
snowfall rates continuing through the first half of Sunday. A sharp
wind shift associated with a secondary arctic front will then move
south across the lake Sunday afternoon, shoving the band onshore and
breaking lake effect apart into a spray of much weaker multibands
and snow showers along the entire south shore and extending south
into the Finger Lakes by late afternoon. This weaker spray of
multibands will continue south of the lake Sunday night and
gradually weaken.

As far as accumulations go, it will depend on how long the band can
stay in one location as it crosses the Tug Hill region and Oswego
County Saturday night through Sunday morning. The residence time is
relatively brief with a steady southward shift, but even so, intense
snowfall rates may still support accumulations of a foot or more
across portions of Oswego County, southern Jefferson County, and
the western slopes of the Tug Hill Plateau. Accumulations may also
get close to low end Watch/Warning criteria in northern Cayuga and
eastern Wayne counties as the band moves south on Sunday.

For headlines, the Winter Storm Watch has been upgraded to a Lake
Effect Snow Warning for Oswego, Jefferson, and Lewis counties. In
Oswego County, it is a long duration warning to cover the the lake
snow today, and then the second event late Saturday through Sunday,
with a break between. For Jefferson and Lewis counties, the warning
is just focused on the second event later Saturday through Sunday. A
Winter Storm Watch has also been issued for northern Cayuga and
Wayne counties for Sunday through Sunday night.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Monday, one last mid level trough will cross the eastern Great
Lakes. This feature will produce some general light snow, and also
support lake enhanced snow east of Lake Erie and Lake Ontario. The
favorable lake effect setup is brief, but may support one more round
of moderate accumulations east of Lake Erie and Lake Ontario.
Boundary layer flow will back to the WSW, so some of the lake
enhancement may impact Buffalo and Watertown.

Monday will be the last wintry day for awhile as the pattern becomes
much more zonal across the US by the middle of next week, forcing
cold air to retreat back into Canada and allowing warmer air to move
northward into the Ohio Valley and Great Lakes. Temperatures will
rise above the 40 degree mark for lower elevations by Wednesday, and
may get close to 50 by Thursday.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Very light lake effect snow showers and flurries southeast of the
Lake Ontario across far northeastern Wayne, northern Cayuga and
southern Oswego counties will continue into this morning, while
slowly working their way further north into Oswego County. A band of
moderate to at times heavy lake effect snow will then develop east
of Lake Ontario today, mainly across Oswego County, but possibly
reaching into far southwestern Lewis County at times. Otherwise, the
remainder of the area will get a well deserved brief break in the
active weather.

Today...westerly flow will keep areas east of the lakes (including
KJHW) in mainly MVFR/low VFR CIGS, while mainly VFR conditions are
expected across the remainder of our TAF sites. Outside of localized
LIFR/IFR VSBY in lake effect snow east of Lake Ontario (south of
KART), VFR VSBYs are expected elsewhere through the day.

Tonight...flow will become southwesterly which will cause the lake
band off Lake Ontario to weaken and start to shift north through the
evening with intermittent MVFR/IFR possible at KART for a few hours
later this evening. Also expecting an uptick in lake effect activity
north-northeast of Lake Erie ahead of an approaching cold front with
MVFR/IFR possible at KBUF/KIAG later this evening as well. MVFR/low
VFR will continue across the higher terrain with mainly VFR
elsewhere. Later tonight, winds back even further to south-southwest
ahead of an approaching strong cold front. Deeper moisture pushing
into the area combined with increasing surface convergence ahead of
the front will lead to a band of lake effect snow developing north-
northeast of Lake Erie, initially across western Niagara County,
possibly sagging as far south as northern Erie County very late
tonight. This will produce MVFR/IFR at KIAG through the second half
of tonight, possibly getting into KBUF toward the tail end of the
TAF period. Snow showers will also start to develop northeast of
Lake Ontario late tonight ahead of the cold front, with restrictions
possible at KART toward the tail end of the TAF period as well.

Outlook...

Saturday...VFR/MVFR with scattered snow showers. Local IFR in lake
effect snow northeast then east of the lakes.

Sunday...VFR/MVFR with scattered snow showers. Local IFR/LIFR in
lake effect snow east of the lakes at the start of the day shifting
to areas southeast and south of the lakes.

Monday...VFR/MVFR with scattered snow showers. Local IFR in lake
effect snow east and southeast of the lakes.

Tuesday...VFR/MVFR with a chance of snow showers east of Lake
Ontario.

&&

.MARINE...
Elevated westerly flow will keep long-duration Small Craft
Advisories in effect into the overnight hours for much of Lake
Ontario, however SCA headlines will remain in effect for far eastern
Lake Ontario right through the weekend.

Otherwise, winds will remain below headline criteria on Lake Erie
through today as high pressure builds in from the Ohio Valley and
central Great Lakes. The break in stronger winds will be brief with
another round of long-duration high end Small Craft Advisory to
marginal gales expected over the weekend, possibly starting as early
as tonight for Lake Erie.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Storm Watch from late Saturday night through Monday
     morning for NYZ004-005.
     Lake Effect Snow Warning until 4 PM EST Sunday for NYZ006.
     Lake Effect Snow Warning from 1 PM Saturday to 1 PM EST Sunday
     for NYZ007-008.
     Winter Storm Watch from Saturday morning through late Sunday
     night for NYZ019-020-085.
MARINE...Small Craft Advisory until 1 AM EST Saturday for LOZ042-043.
         Small Craft Advisory until 5 AM EST Saturday for LOZ044.
         Small Craft Advisory until 4 AM EST Monday for LOZ045.

&&

$$

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

NWS BUF Office Area Forecast Discussion