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FXUS61 KBUF 151117
AFDBUF
Area Forecast Discussion
National Weather Service Buffalo NY
617 AM EST Mon Dec 15 2025
.SYNOPSIS...
One more round of lake enhanced snow will bring light to moderate
accumulations today through this evening east and northeast of Lake
Erie including the Buffalo area, and moderate to locally heavy
accumulations east of Lake Ontario. The lake effect snow will taper
off east of Lake Erie overnight, and by late Tuesday morning east of
Lake Ontario. A warming trend will then develop through the middle
of the week with less active weather. A strong cold front will then
cross the eastern Great Lakes Thursday night, bringing strong, gusty
winds and a period of rain. Much colder air will pour back into the
region Friday with lake effect snow showers.
&&
.NEAR TERM /THROUGH TONIGHT/...
A northwest flow of cold air continues to support areas of light
lake effect and upslope snow showers southeast of the lakes early
this morning. Boundary layer flow will back to the WSW through the
morning hours, carrying lake effect snow northward off both lakes.
The pure lake effect regime will evolve into lake enhanced snow
today as another clipper shortwave and surface cold front moves east
across the eastern Great Lakes this afternoon.
Off Lake Erie...
Weak upslope flurries and light snow showers will become better
organized again this morning on westerly flow across the western
Southern Tier. This may produce a fresh 1-2" of accumulation across
Chautauqua and western Cattaraugus counties this morning.
The band of lake enhanced snow will then move north to the Buffalo
Metro area from late morning through this evening. The band of snow
will likely broaden out over a larger footprint for several hours
this afternoon near the time of the trough passage when synoptic
scale moisture and ascent peak, before contracting back to a more
localized lake effect band this evening and settling back south
before mostly dissipating overnight. If the lake response lasts long
enough through Tuesday morning, there may be some risk of a period
of freezing drizzle as inversion heights lower and deep moisture is
stripped away, leaving behind a cloud bearing layer lacking ice
nuclei.
As far as accumulations go, expect a general 2-4" in the area of
lake enhancement across the Niagara Frontier, with some local 5"
reports possible where the lake snow lasts the longest.
Off Lake Ontario...
Weak multiple bands in northwest flow early this morning will
consolidate back into a more concentrated area of accumulating snow
across northeast Wayne and northern Cayuga counties by mid morning,
with this band then moving northeast across Oswego County late
morning through early afternoon before ending up in Jefferson County
and the northern Tug Hill by mid afternoon. The band should reach
its strongest late afternoon through the evening hours across
southern Jefferson County and the northwest portion of the Tug Hill
Plateau, with 2" per hour snowfall rates possible. Expect a
weakening trend by late tonight as inversion heights begin to lower
and better synoptic scale moisture moves off.
As far as accumulations go, expect an additional few inches in Wayne
County this morning, and 3-6" across far northern Cayuga County and
much of Oswego County as the band swings northeast across the area.
Far northern Oswego County may see 6-10" if the stronger phase of
the band this evening clips the county. The greatest accumulations
will be found across southern Jefferson County and the northwest
portion of the Tug Hill Plateau, with 8-16" in the most persistent
band.
Outside of the main lake effect areas, the passing clipper cold
front and trough will produce a few light snow showers this
afternoon with a dusting of accumulation in spots. It will become
windy enough near Lake Erie and across the Niagara Frontier to
support some blowing snow in open areas from late morning through
evening.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A quasi-zonal flow will become established during this period,
bringing a series of fast-moving systems through the area for the
foreseeable future.
Starting out Tuesday, mid level trough axis will pull east of the
area, stripping away deeper moisture, while in the lower levels
strong WAA will ensue through the day as a warm front moves through
the area. This will send 850mb temps from the low to mid negative
teens C to start the day, to at or a little above 0C by the end of
the day. The combination of strong WAA and depleting moisture will
cause equilibrium levels to crash, quickly ending any lingering lake
effect snow showers from west to east on both lakes. This will leave
nothing more than a few very light snow showers northeast of Lake
Erie Tuesday morning, with possibly another inch or so across
southern and central Jefferson County (including Watertown) as
what`s left of the Lake Ontario band rapidly weakens and shifts
north through the county as low level flow will back to south-
southwest by the end of the day.
Mainly dry weather expected Tuesday night as transient ridging moves
across the area. A dry cold front moving across the region later
Tuesday night will cause breezy to windy conditions to develop as
the pressure gradient tightens and a 40-50 knot LLJ associated with
a strong area of low pressure (~980mb) well to the north moving east
across James Bay moves overhead. Expect some gusts to around 30 mph
ahead of the front first half of Wednesday night, with gusts to 40
mph or so later Tuesday night across western NY as CAA in the wake
of the front helps mix stronger winds off the deck down to the
surface.
Wednesday...breezy to windy conditions will continue through much of
the day as the 40-50 knot LLJ remains overhead. Southwest winds will
veer west with gusts upwards of 40 mph again possible. Otherwise, a
quick shot of cooler air combined with passing of mid level trough
axis may produce some lake enhanced and upslope snow showers across
the higher terrain, mainly east of Lake Ontario. Mid level trough
and associated deeper moisture quickly pulls east and gets replaced
by transient high pressure Wednesday night, bringing a return to a
brief period of dry weather and lowering winds.
Temperatures...Highs mid 20s to low 30s Tuesday and mainly 30s
Wednesday. Lows Tuesday night upper teens to upper 20s and mainly
mid to upper 20s Wednesday night, with temperatures starting to rise
late Wednesday night across western NY as the next surge of warmer
air starts to work in.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Quasi-zonal flow continues through the period bringing a series of
fast-moving systems from west to east across the northern CONUS and
southern Canada. Exact track of these systems will drive exactly
what type of weather our area sees, as the track that each of these
features takes will determine the dividing line between very cold
air to the north and much warmer air to the south. Not shockingly
there will also be a lot of wind during this period with this setup,
however the biggest concern will be during the first half of the
period when strong downslope winds will be possible ahead of a
strong cold front trailing a powerful low pressure system trekking
across Ontario into Quebec.
Ridge quickly exits to our east Thursday as a sharp, but progressive
mid and upper trough deepens across the middle and upper Mississippi
Valley with a strong 985-990mb surface low pressure system near the
SOO. Strong WAA will boost temps into the 40s for all but the
highest terrain Thursday. Medium range guidance still differs some
on the exact strength and track of the system, however expect a
track east-northeast to northeast across Ontario into the southern
half of Quebec by Friday. It will certainly be windy during this
time, but just how strong those winds may be will be determined by
the exact position and if the low is strengthening or weakening as
it passes by to the northwest and north of the area. That said, an
associated south to south-southeast ~70 knot LLJ will move over the
area Thursday night ahead of the main cold front. The fact that
these winds are on the warm side will fortunately limit the mixing
down of these stronger winds aloft to some degree with poor lapse
rates, however this does look like a better setup for mechanical
mixing of these winds to the surface for favored downslope areas
across north to north-northwest facing slopes. Bottom line...stay
tuned to future forecasts as higher resolution model data becomes
available and the finer details become better resolved. Also of
note, but even more uncertain...there is also the chance that a line
of strong low-topped convection could also accompany the frontal
passage Thursday night. With winds of this magnitude off the deck,
potential for strong convective winds will also be a possibility.
We quickly transition back to winter on Friday as a secondary cold
front plows across the area with rain rapidly changing over to snow
as temperatures fall through the 20s (teens higher terrain) along
with a 40-50 knot LLJ keeping a gusty west wind in place within a
strong CAA regime. This will also set the stage for a quick-hitting,
yet possibly impactful lake enhanced and upslope snow event to close
out the work week, especially east of Lake Ontario.
For the weekend...transient ridge and warmer air quickly shut down
lake enhanced and upslope snows later Friday night into Saturday.
Only to be followed by yet another cold front Saturday night with
cooler temps to finish out the weekend. Confidence on exact track,
timing, and strength of these features over the weekend is low to
moderate at this distance in time, but overall expect some unsettled
weather (rain/snow?) with some dry time built in, along with breezy
conditions and temperatures near to a bit above average.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Northwest flow will continue to support weak lake effect and upslope
snow showers southeast of the lakes early this morning with areas of
IFR VSBY and MVFR CIGS, especially southeast of Lake Ontario from
west of KROC to KFZY and southward into the Finger Lakes.
A clipper trough and cold front will cross the eastern Great Lakes
today, forcing boundary layer flow to back to the WSW. This will
allow lake effect snow to become better organized and move to
east/northeast of both lakes.
Off Lake Erie, expect lake effect snow to organize over the western
Southern Tier this morning including KJHW, then move northward to
the Niagara Frontier including KBUF and KIAG by midday, with areas
of IFR VSBY and MVFR CIGS. The snow will be most organized this
afternoon and evening before shrinking in coverage and diminishing
in intensity while settling south of KBUF overnight.
Off Lake Ontario, snow southeast of the lake will consolidate into a
more organized band this morning east of KROC and west of KFZY with
IFR/LIFR. This band will move northeast across Oswego County late
morning through early afternoon before reaching Jefferson County and
the northern Tug Hill by mid afternoon. This band will become
heaviest this evening with local VLIFR in the band just south of
Watertown, with IFR/LIFR impacting KART on the northern edge of the
band.
Outlook...
Tuesday...Local IFR in lake effect snow east of Lake Ontario early,
otherwise improving to VFR.
Wednesday...Mainly VFR, with a chance for a few rain/snow
showers and MVFR east of Lake Ontario.
Thursday...VFR deteriorating to MVFR/IFR with rain developing along
with strong southerly winds. Rain changes to snow late Thursday
night along a cold front passage. Strong winds veer from southerly
to westerly.
Friday...Localized IFR in lake effect snow east/southeast of the
lakes. Otherwise MVFR/VFR with scattered light snow showers. Gust
westerly to northwesterly winds.
&&
.MARINE...
Winds will back to the southwest and increase today as a clipper
cold front crosses the lower Great Lakes, bringing solid Small Craft
Advisory conditions to Lake Erie and Lake Ontario. Winds will
gradually diminish late tonight through Tuesday, but still remain at
or near Small Craft Advisory criteria.
Another cold front passes the lower Great Lakes Tuesday night
through Wednesday, with sustained winds increasing to 30 knots on
both Lake Erie and Lake Ontario, with a small chance of a brief
period of gales.
Strong low pressure will move across Ontario and Quebec Thursday
through Friday, with a trailing powerful cold front crossing the
lower Great Lakes late Thursday night. Southerly winds will increase
to gale force Thursday ahead of the cold front, then swing around to
westerly Friday behind the front with gales likely continuing on
both lakes.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory from 10 AM this morning to 7 AM EST
Tuesday for NYZ001-002-010>012-085.
Winter Weather Advisory until 1 PM EST this afternoon for
NYZ004.
Lake Effect Snow Warning until 1 PM EST this afternoon for
NYZ005.
Lake Effect Snow Warning until 1 PM EST Tuesday for NYZ006>008.
MARINE...Small Craft Advisory until 1 AM EST Tuesday for LEZ020.
Small Craft Advisory until 5 AM EST Tuesday for LEZ040-041.
Small Craft Advisory until 4 AM EST Tuesday for
LOZ042.
Small Craft Advisory until 10 AM EST Tuesday for
LOZ043>045.
&&
$$
SYNOPSIS...Hitchcock
NEAR TERM...Hitchcock
SHORT TERM...JM
LONG TERM...JM
AVIATION...Hitchcock
MARINE...Hitchcock
NWS BUF Office Area Forecast Discussion
