916
FXUS61 KBUF 090638
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
138 AM EST Tue Dec 9 2025

.SYNOPSIS...
Two waves of low pressure will pass by our region, with the first to
arrive this afternoon in the form of widespread, but light, synoptic
snow. Southwest winds behind this wave will deposit several inches
of lake effect snow downwind of Lake Erie on a southwest flow this
evening and into tonight, with a few inches of snow also falling
through the Saint Lawrence Valley off Lake Ontario tonight. A more
potent storm system will arrive later tonight, with snow and gusty
winds, with this snow mixing with rain late tonight and Wednesday
across lower terrain, while hills tops may remain as just snow
through the event, with this snow heavy at times.

&&

.NEAR TERM /THROUGH TODAY/...
Surface high pressure over the eastern Great Lakes will ensure
generally dry and quiet albeit frigid weather remains in place
through this morning. Temperatures remain some 15 to 20 degrees
below normal tonight.

The surface ridge axis will slide south and east of the Great Lakes
and past the spine of the Appalachians overnight. Low level
flow should begin to turn southerly and the overhead airmass
modify a few degrees as a result. Despite this, it will still be
cold enough with winds remaining light enough such that with
the snowpack across the region, temps should easily slide back
into the single digits early this morning, with many spots
across the interior falling below zero. Otherwise, a thin plume
of low level moisture will continue off the east end of Lake
Ontario overnight. Combined with diurnal land-breeze
convergence and some enhancement from the lake, this will
continue to produce a weak band of LE snow off the eastern end
of the lake. Band will remain closer to the lakeshores from
roughly Oswego to Watertown, with these areas possibly picking
up a dusting to perhaps a localized inch or so.

Our stretch of quieter weather will be cut short Tuesday as a
weakening clipper system tracks through the Upper Great Lakes,
becoming further disorganized and diffuse as it moves east. The mid-
level shortwave driving this system will make its way through the
forecast area Tuesday afternoon into early Tuesday evening, with a
warm frontal segment moving through from west to east. This will
cause light snow to once again overspread much of the region, with
lake enhancement developing northeast of the lakes (mainly Lake
Erie) late in the day. A stiff southerly flow and subsequent
downslope drying/upslope enhancement will should yield minimal
accumulations by the evening (generally 0.5" or less) in the Genesee
Valley and Finger Lakes, as well as on the leeward side of the Tug.
The higher amounts are expected across the Niagara Frontier
including the Buffalo Metro and east of Lake Ontario across the
southern slopes of the Tug Hill Plateau itself. Snowfall in
these areas should still be minor with 1-3" by the late
afternoon, though more will be on the way as lake effect bridges
the short gap until the next synoptic system arrives...More on
that in the short term below.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
A complex forecast scenario will unfold Tuesday night through
Wednesday night as a strong clipper low passes by just to our
north. There continues to be enough spread in model guidance to
bring considerable uncertainty to the forecast in terms of
snowfall amounts, precipitation type, and wind potential.

Tuesday evening, a brief window of lake effect snow northeast of
Lake Erie and Lake Ontario ahead of the clipper system may bring a
few inches of snow to the Niagara Frontier (including the Buffalo
Metro area) and northern Jefferson County. Ongoing warm advection
and lowering inversion heights ahead of the clipper will then shut
down the lake response overnight.

The surface low will likely pass just north of the area across
southern Ontario Wednesday. The GFS remains on the southern edge of
the guidance envelope, taking a weaker low directly over Lake Erie
and Lake Ontario. If this were to verify, there would be much less
wind, and precip type would stay snow for a greater share of the
event. This low is not favored climatologically, and will thus favor
the farther north solutions seen in other guidance.

A period of snow will break out late Tuesday night through Wednesday
morning in the warm advection and isentropic upglide ahead of the
system. Assuming the farther north track verifies, lower elevations
of Western and Central NY will then mix with, or change to rain for
a time Wednesday, while the high terrain of the Southern Tier has a
better chance of remaining all snow, and also the higher terrain
east of Lake Ontario. The lower elevation rain would then change
back to snow Wednesday evening as cold advection ramps up following
the passage of the clipper cold front, with wrap around upslope snow
and the start of lake effect adding some additional accumulations
Wednesday night.

As far as accumulations go, the greatest snow amounts will be found
across the higher terrain of the Tug Hill Plateau and western
foothills of the Adirondacks where upslope will enhance QPF, and
precipitation is most likely to remain all snow. This area may see
totals of 8-12+" from early Wednesday morning through Thursday
morning. These higher amounts would be limited to the high terrain,
with the surrounding lower elevations of the eastern Lake Ontario
region seeing 3-6" accumulations.

Across Western NY, total accumulations from late Tuesday afternoon
through Thursday morning may reach the 3-6" range across the Niagara
Frontier, and 4-9" across the higher terrain of the western Southern
Tier. It is important to note that this will fall in 3 different
batches, lake effect Tuesday evening, then warm advection snow late
Tuesday night/early Wednesday morning, then wrap around snow and
lake enhancement Wednesday night. Each of these phases will produce
a few inches each. There will be melting during the day Wednesday
when temperatures rise well above freezing, especially across lower
elevations.

It will turn windy as this system moves through the area, but
uncertainty with low track, intensity, and associated wind fields
makes this a highly uncertain wind forecast. If the farthest north
and strongest solutions of the NAM/HRRR verify, we can expect high
end Wind Advisory or low end warning criteria gusts (55+mph)
northeast of Lake Erie Wednesday, while the farther south and weaker
GFS solution would keep winds well below wind advisory criteria.
Most model solutions are weaker than the worst case NAM/HRRR, so for
now we kept forecast wind gusts near the low end of advisory range
northeast of Lake Erie but expect adjustments as the event nears and
forecast certainty increases.

Thursday through Thursday night cold air will pour back into the
eastern Great Lakes, supporting accumulating lake snows southeast of
the lakes. There is typical uncertainty with wind direction and snow
amounts at this time range, but in general expect the potential for
moderate snow accumulations across the western Southern Tier off
Lake Erie, and near or just east of Rochester to Oswego County off
Lake Ontario.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
An active and cold pattern will continue Friday through early next
week as a deep longwave trough remains over eastern North America.
This trough will continue to support below average temperatures and
almost daily chances of snow from a combination of clipper systems
and lake effect.

Model guidance continues to show considerable run to run differences
with the synoptic setup through the weekend, which results in
uncertainty with respect to lake effect band placement and
intensity. In general, the very progressive pattern with frequent
clipper shortwaves will likely prevent wind direction and band
placement staying the same for any length of time. This will limit
the potential for a large lake effect event, but also spread the
wealth of accumulating snow to a multitude of different wind
directions and locations over time.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
High pressure sliding east of the area will keep mainly VFR flight
conditions intact through midday/early Tuesday afternoon. Exception
will be remainder of tonight into the first couple of hours Tuesday
morning east of Lake Ontario as a weak band of localized lake effect
snow off the southeast end of Lake Ontario with limited inland
extent will continue to weaken and move north across the Lake
Ontario region. VSBYs around 3SM in -SHSN and marginal MVFR CIGS
have been observed at KFZY. If this band holds together, a brief
period of marginal MVFR/low VFR CIGS will be possible in and around
KART from around 10Z-13Z, however any snow shower activity should be
very light.

Flight conditions will then rapidly deteriorate from early/mid
afternoon Tuesday through the end of the TAF period as a warm front
extending south from a weak Clipper system approaches, then moves
across the area. Expect MVFR CIGS into western NY by mid afternoon,
spreading east to the eastern Lake Ontario region by around early
evening. A brief period of light snow will also be possible along
and ahead of the boundary. This may bring a brief period (1-3 hours)
of MVFR/IFR VSBY with timing mirroring the aforementioned onset of
MVFR CIGS. A period of localized lake effect snow is then expected
to develop in the wake of the warm frontal passage with intermittent
MVFR/IFR VSBYs northeast of Lake Erie possibly impacting KBUF and/or
KIAG Tuesday evening into the early overnight.

Southerly to southwesterly flow will ramp up for Tuesday afternoon
and evening as well, with gusts mainly in the 20-25 knot range,
however a few gusts to 30 knots is not out of the question.

Outlook...

Tuesday night...Mainly MVFR/IFR with snow potentially mixing with
rain late in the night.

Wednesday...VFR/MVFR with rain and snow showers. Breezy, with gusts
20-30kts in many areas. Gusts to 35kts possible at KBUF/KIAG.

Thursday...VFR, with MVFR/IFR in scattered to numerous snow showers.

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

&&

.MARINE...
High pressure will shift southeast of the lakes overnight with
light winds and minimal wave action.

The offshore flow will increase and begin to turn southwesterly as a
weak system moves east of the Upper Great Lakes Tuesday, which will
then be followed by a more potent area of low pressure on Wednesday.
Depending upon the track of the surface low, gales are possible
Tuesday - Wednesday, with Wednesday the more favorable day,
especially over Lake Erie. A Gale Watch was issued for the
eastern end of Lake Erie Wednesday.

Westerly winds will subside below gale force later Wednesday night
into Thursday, though remain elevated through the end of the week.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Storm Watch from late tonight through Thursday morning
     for NYZ006>008.
     Winter Weather Advisory from 1 AM to 10 PM EST Wednesday for
     NYZ012-019>021-085.
MARINE...Small Craft Advisory from 1 PM this afternoon to 4 AM EST
         Thursday for LEZ020.
         Small Craft Advisory from 7 AM this morning to 4 AM EST
         Wednesday for LEZ040-041.
         Gale Warning from 4 AM to 7 PM EST Wednesday for LEZ040-
         041.
         Small Craft Advisory from 3 PM this afternoon to 10
         AM EST Friday for LOZ042.
         Small Craft Advisory from 9 PM this evening to 6 PM EST
         Saturday for LOZ043>045.

&&

$$

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