015
FXUS61 KBUF 101909
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
209 PM EST Wed Dec 10 2025

.SYNOPSIS...
Low pressure over southern Ontario will push across Lake Ontario
through early this evening. A mix of rain and snow across the lower
elevations and snow across the higher terrain will change back to all
snow following the passage of the system`s trailing cold front late
today and this evening...with the widespread snowfall then giving
way to bands of accumulating lake effect snow southeast of the lakes
tonight through Thursday night. Weakened lake snows will then lift
north on Friday out ahead of the next clipper system...with the
latter feature then crossing our area over the weekend.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of this writing...regional observations indicate that snow
continues mix with and transition to rain across the lower
elevations southeast of Lake Ontario with continued slow but steady
warming of the boundary layer...with wet snow continuing elsewhere.
Expect this general trend to continue through 4 pm...with the lower
elevations south of Lake Ontario seeing temperatures peak in the
upper 30s to around 40.

Very late this afternoon and this evening...the area of low pressure
responsible for the mix of rain and snow will make its way east
across Lake Ontario...and in the process will push its trailing cold
front southeast and across our region. Cold advection following the
frontal passage will drive a changeover back to all snow from west
to east...with the synoptic pcpn then fairly quickly tapering off in
a similar manner a few hours later. For areas outside of any
headlines...this renewed snowfall could accumulate up to another
inch through this evening...with 2-4" likely through that time
across the higher terrain east of Lake Erie...and another 3-6"
possible across the higher terrain east of Lake Ontario.

As cold air deepens across the region tonight and Thursday
morning...the leftover synoptic/upslope snows east of the lakes will
transition to areas of lake effect snow east-southeast of the lakes
as the low level flow veers a bit more to the west-northwest. The
developing lake response will be hampered initially tonight by
strong mid-level dry slotting wrapping in behind the departing low
as well as a bit of shear...however this will change as we push into
the day Thursday as synoptic moisture deepens and upstream
connections to Lake Huron/Georgian Bay develop. This will result the
bands increasing in organization ESE of the lakes during Thursday...
with this better-organized state the lasting into Thursday evening.
The bands will then weaken again as we push through the remainder of
Thursday night in concert with diminishing moisture aloft and a
slowly falling cap.

Off Lake Erie...signs continue to point to a Lake Huron connection
potentially supporting a narrower swath of embedded additional 6-10"
accumulations somewhere in the advisory area between later tonight
and Thursday night...however guidance remains inconsistent on the
placement of this connection/any enhanced snowfall...as well as its
duration in any given location. With this in mind...have refrained
from upgrading any part of the existing Winter Weather Advisory east
of Lake Erie to a warning for now...though such a short-fused
upgrade certainly remains possible if a better consensus on the
upstream connection and the placement/duration of any resulting
enhanced snowfall develops.

Off Lake Ontario...guidance remains in good agreement on developing
a decent band of lake effect snow across Wayne and Northern Cayuga
counties late tonight/Thursday morning...then largely maintaining
this (with some subtle north-south oscillations possible at times)
through at least the first half of Thursday night. Here...a narrow
swath of 5-10" accumulations appears likely...and with this in mind
have upgraded the Winter Storm Watch for these areas to a Lake
Effect Snow Warning.

East of Lake Ontario...lingering upslope snows will also continue to
affect the higher terrain of the Tug Hill and western Adirondack
foothills overnight into Thursday morning...though these will tend to
slowly weaken over time. Expect another 2-4" of snow in these areas
between the second half of tonight and Thursday morning.

In all three of the above areas...increasing westerly to west-
northwesterly winds will also gust to 30-40 mph at times tonight
through Thursday/Thursday evening...with localized gusts to 45 mph
or so possible along the southeastern shore of Lake Ontario. This
will lead to areas of blowing and drifting snow...especially later
tonight/Thursday/Thursday evening as the colder airmass deepens
across our region and results in the snow becoming fluffier over
time.

Outside of the lake snows...expect just some scattered snow showers
and flurries later tonight through Thursday night...with the
incoming colder airmass resulting in lows falling into the mid teens
to lower 20s tonight and highs mostly pulling back to the upper
teens to mid 20s Thursday. Lows Thursday night will then settle into
the single digits east of Lake Ontario...and to the mid/upper teens
elsewhere.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Exiting mid-level trough across the Northeast, will briefly give way
to a ridge across the central Great Lakes Friday. The next trough
will dive southeast across the Great lakes late Friday night through
Saturday, and then starting to pivot across the eastern Great Lakes
Saturday night.

With this upper level pattern in mind, lake effect snow southeast of
Lakes Erie and Ontario will be ongoing Friday morning. Off of Lake
Erie, dry and slightly warmer air will filter across the region
Friday, lake effect snow across the western Southern Tier will
weaken and taper off supporting an additional few tenths of an inch
of snow. Meanwhile off of Lake Ontario, the colder wrap around air
from the departing low across the Northeast will hang on. Therefore,
lake effect snow southeast of the lake will shift north due to winds
veering from northwesterly to westerly and southwesterly by Friday
night. Overall an additional few inches will be possible as the band
traverses northward.

As the next clipper system dives southeast across the Great Lakes
Friday night through Saturday, an associated cold front will pass
from west to east. Associated lift and moisture will support
widespread snow to spread across WNY Friday night and Saturday
morning, with some lake enhancement possible northeast of Lake Erie.
In the wake of the frontal passage Saturday morning, lake effect
snow will continue east of Lake Erie Saturday and Saturday night. As
the cold front tracks eastward, widespread snow will shift eastward
with some lake enhancement possible east of Lake Ontario late
Saturday morning into Saturday afternoon, with lake effect to follow
Saturday night.

Snowfall amounts from the widespread snow will be light with up to
an inch possible. Multiple inches of lake effect snow will then be
possible east of the lakes Saturday and Saturday night, with the Tug
Hill likely seeing the highest of the accumulations.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Broad longwave troughing will persist Sunday and Sunday night before
pulling east into the Atlantic Ocean Monday. A pocket of colder air
(readings of -20C to -18C at 850mb) will slide east across the
region Sunday and Sunday night, supporting ongoing lake effect snow
east/southeast of Lakes Erie and Ontario to prevail through Monday.
Backing winds from westerly to northwesterly Sunday will shift lake
effect bands from east of the Lakes to southeast of the Lakes.

A broad mid-level ridge over much of the western half of the CONUS
will begin to infiltrate into the Great Lakes Monday and Tuesday.
Overall, warming aloft and attendant dry air associated with the
surface high overhead Monday night through Tuesday will help to
weaken ongoing lake effect.

Should note, it will be cold Sunday through Monday, with the pocket
of colder air overhead. Expect temperatures to be well below average
for the later half of the weekend and into the start of the new work
week.

The next surface low will pass east across eastern Canada Tuesday
night through Wednesday, well north of the region. However,
associated surface fronts will sweep across the region Wednesday,
supporting the chances for some precipitation. A large warming trend
associated with the broad ridge, will support most of this
precipitation to fall in the form of rain.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
As of this writing...regional observations indicate that snow
continues mix with and transition to rain across the lower
elevations southeast of Lake Ontario with continued slow but steady
warming of the boundary layer...with wet snow continuing elsewhere.
Expect this general trend to continue through 21z...with a mix of
LIFR/IFR to MVFR conditions prevailing.

Very late this afternoon and this evening...the area of low pressure
responsible for the mix of rain and snow will make its way east
across Lake Ontario...and in the process will push its trailing cold
front southeast and across our region. Colder air following the
frontal passage will drive a changeover back to all snow from west
to east...with the synoptic pcpn then fairly quickly tapering off in
a similar manner a few hours later. The exceptions to this will be
east of Lake Ontario where lighter upslope snows will linger across
the higher terrain...and east-southeast of the lakes where areas of
lake effect snow will develop and then continue through Thursday. In
these latter areas expect general IFR/LIFR to prevail through
Thursday...with flight conditions elsewhere improving to a mix of
MVFR/VFR.

Outlook...

Thursday night...VFR/MVFR with scattered light snow showers. Areas
of heavier lake effect snow with IFR/LIFR southeast of the lakes.

Friday...MVFR/IFR east of Lake Ontario in weakening lake
snows...with mainly VFR elsewhere.

Friday night through Sunday...IFR east of the lakes in snow showers
and areas of lake effect snow...with MVFR/IFR in scattered to
occasionally more numerous snow showers elsewhere.

Monday...VFR/MVFR with a chance of snow showers.

&&

.MARINE...
Low pressure will push across Lake Ontario through this evening...
while sliding its trailing cold front east across New York State.
Out ahead of the front a brief period of southwesterly gales will
continue across Lake Erie into early this evening...with developing
westerly to northwesterly gales then expected to follow the passage
of the low tonight and Thursday across the eastern half of Lake
Ontario. For the above reason...the Gale Watch for eastern Lake
Ontario has been upgraded to a Gale Warning. Outside of the above...
elevated southerly to southwesterly winds out ahead of the front
will be followed by elevated westerlies to northwesterlies tonight
through Thursday night/Friday...for which Small Craft Advisories
remain in effect as outlined below.

Looking further out into this weekend...another round of elevated
winds will accompany the approach and passage of a clipper system...
likely necessitating another round of at least higher-end advisories
as we push through the weekend.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Lake Effect Snow Warning from 1 AM Thursday to 7 AM EST Friday
     for NYZ004-005.
     Winter Storm Warning until 1 PM EST Thursday for NYZ006>008.
     Winter Weather Advisory until 4 AM EST Friday for NYZ012-
     019>021-085.
MARINE...Small Craft Advisory until 4 AM EST Thursday for LEZ020.
         Gale Warning until 7 PM EST this evening for LEZ040-041.
         Small Craft Advisory until 4 AM EST Friday for LOZ030.
         Small Craft Advisory until 10 AM EST Friday for LOZ042.
         Small Craft Advisory until 1 AM EST Thursday for
         LOZ043>045.
         Gale Warning from 1 AM to 10 PM EST Thursday for
         LOZ043>045-063>065.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...JJR
MARINE...JJR