440
FXUS61 KBUF 111136
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
636 AM EST Tue Nov 11 2025

.SYNOPSIS...
Wintry weather continues through tonight as cold air flowing into
the region generates lake effect snow showers at times. Favorable
areas for accumulating lake snow will be south and southeast of the
lakes this morning before diminishing this afternoon. The flow then
backs tonight into Wednesday morning, such that a southwest flow
will push diminishing lake snows towards Buffalo and Watertown. Mid
to late week warming will change the bulk of the precipitation back
to plain rain as unsettled weather ends just before the start of the
weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
The core of a deep upper level trough over central NY this morning
will continue to shift east towards the Gulf of Maine through this
evening as a sfc low deepens and tracks north across eastern Quebec.
In its wake, a progressive sfc ridge will build over the forecast
area by this afternoon. Ongoing NW flow lake effect snow showers
will continue through the remainder of the morning hours, then
gradually taper off as dry air subsidence brings down inversion
heights and depletes DGZ moisture. The focus for heaviest snow until
then will be southeast of Lake Erie across the Chautauqua Ridge as an
upstream connection to Lake Huron wraps northward, and along the
south-southeastern shoreline of Lake Ontario with upstream
connections to Georgian Bay impacting the Niagara Frontier at times.
While some lake effect/upslope snow showers may continue into the
afternoon, the overhead airmass will already be modifying behind the
trough axis enough for all areas at the lower elevations to rise
several degrees above freezing, not quite enough for a mix with rain
though it should help melt the snow on the ground and area roadways.

Behind the surface ridge, a negatively tilted shortwave and broad
surface trough will descend southeast across the Great Lakes this
evening and through tonight. This will cause the prevailing flow to
back to the southwest, which in combination with the added fetch,
moisture and forcing, allow newly formed bands of lake effect precip
off both lakes to rapidly whip northward. Off Lake Erie, the band
will pass over the Buffalo Metro and into Niagara Country before
daybreak Wednesday, then slowly trek back southward over the course
of the day. The band should be due east of the lake by the early
evening. The band off Ontario will lag behind by several hours,
though it will move northward from the the Tug Hill region after
midnight before moving across the Watertown Metro. The band is
expected to linger north of the metro through the morning before
settling back towards the Tug Hill by the evening.

The main forecast challenge tonight into Wednesday morning continues
to be p-type and how efficient dendrite-growth processes will be. As
previously alluded to, the airmass will be modifying this period,
with a slow warming of temps aloft through tonight and a more rapid
warming Wednesday. This will inevitably cause a mix with rain to
occur Wednesday morning, first across WNY with a complete changeover
in most areas by the afternoon, though the timing of this changeover
remains a bit uncertain. In addition, BUFKIT soundings indicate this
warmer airmass should lead to an elevated DGZ with a capping
inversion below it, despite near total saturation through the column
at times. This should help preclude the development of larger, more
efficiently accumulating dendrites. This said, given the timing of
the bands around the Wed morning commute, their proximity to the
metro areas, and ongoing NW flow lake effect this morning, have
opted to include N. Erie, Lewis, and Jefferson to the latest rounds
of advisories, and extend Niagara/Orleans until Wednesday morning.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Longwave trough axis lying across the Northeast Wednesday night will
allow a shortwave trough to slide southeast through the base of the
longwave trough, which will pull the trough axis east into the
northern Atlantic Thursday and Thursday night. Meanwhile, a ridge
will lie across the upper Great Lakes and northern Midwest. Under
the exiting trough`s regime, cool northwest winds will continue to
filter across the region Wednesday night through Thursday night.
While temperatures aloft at 850mb will continue to support lake
effect showers, temperatures will be warmer (average around -5C)
than the current airmass and therefore support mainly rain showers
and a few higher terrain and night time snow showers southeast of
both lakes Erie and Ontario Wednesday night through Thursday night.
This being said, areas southeast and east of both Lakes Erie and
Ontario Wednesday night through Thursday night can expect between a
half inch to three quarters of an inch of rain, with locally higher
amounts possible. Additionally, for the areas cold enough to support
night-time (mainly across the higher terrain) snow accumulations of
a few tenths of an inch will be possible.

Showers will begin to taper off Thursday night as the ridge begins
to push east into the far western portions of the region.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Amplified upper level and mid-level trough-ridge-trough pattern late
this week and into the start of next week will support mainly active
weather to persist with a brief lull in activity this weekend.

Heading into Friday, exiting mid-level trough in the northern
Atlantic, will allow ridging and associated surface high pressure to
push east across the central and lower Great Lakes. Warming
temperatures aloft (warming towards 0C at 850mb) will help end lake
effect rain showers and night time higher elevation snow will peter
off Friday and Friday night.

Surface high pressure shifting overhead Saturday will support a
period of dry weather. However this period of dry weather will be
short term as the next mid-level trough heads towards the region
late Sunday night and into the start of next week. Warmer thermal
profiles continue to support mainly rain showers Sunday afternoon
through Monday.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Variable flight conditions as an area of upper level low pressure
will track east of the region through tonight. Synoptic moisture and
cold northwesterly flow in its wake will allow for widespread lake
effect snow showers to continue downwind of the lakes this morning,
with a particular focus southeast of Lake Erie and south-southeast
of Lake Ontario. Inside the main lake effect areas expect mainly
MVFR cigs and MVFR/IFR vsbys, with a gradual improvement to VFR/MVFR
elsewhere. The snow coverage and intensity will gradually taper off
through the day today with vsbys becoming mainly VFR as drier air
moves overhead.

Tonight, more focused bands of lake effect snow will rapidly come
northward off both lakes, with impacts likely at KBUF, KIAG, and
KART. Snow intensity should be modest at best though localized
MVFR/IFR will certainly be possible. A changeover to rain may occur
late in the band off Lake Erie, though confidence in timing is low.
VFR/MVFR with scattered snow showers will prevail elsewhere.

Outlook...

Wednesday...MVFR/IFR with rain and snow, especially east and
northeast of the lakes. Windy.

Thursday...Areas of MVFR with rain and snow showers likely,
especially southeast and east of the lakes.

Friday...MVFR/VFR with a chance for rain and snow showers.

Saturday...Mainly VFR.

&&

.MARINE...
A surface low is along the New England shoreline will continue to
deepen as it tracks northward towards Quebec today. This will
maintain a prolonged period of strong winds over the eastern Great
Lakes with high end small craft conditions on the Lakes. As winds
turn southwesterly this evening, a short period of low-end Gales is
expected on Lake Erie into early Wednesday morning.

Waves are expected to remain 4-feet and greater through Thursday
evening on the eastern Great Lakes, and not until Friday when
surface high pressure approaches the Lower Lakes will winds and
waves fall below small craft conditions.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory until 10 AM EST Wednesday for NYZ001-
     002-010.
     Winter Weather Advisory until 1 PM EST this afternoon for
     NYZ003>006-020-085.
     Winter Weather Advisory until 1 PM EST Wednesday for NYZ007-
     008.
     Lake Effect Snow Warning until 1 PM EST this afternoon for
     NYZ019.
MARINE...Small Craft Advisory until 7 PM EST this evening for LEZ040-
         041.
         Gale Warning from 7 PM this evening to 4 AM EST Wednesday
         for LEZ040-041.
         Small Craft Advisory until 7 PM EST this evening for
         LOZ042>045.

&&

$$

SYNOPSIS...PP/Thomas
NEAR TERM...PP
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...PP
MARINE...PP/Thomas