017
FXUS61 KBUF 160020
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
720 PM EST Mon Dec 15 2025

.SYNOPSIS...
Bands of lake effect snow will continue east and northeast of both
Lower Great Lakes tonight, with a few more inches of snow
accumulating downwind of Lake Erie and locally moderate to heavy
snow east of Lake Ontario yielding over a foot of fresh snow. The
lake snows will taper off late tonight and Tuesday morning, with a
brief period of quiet weather, with moderating temperatures. A
strong cold front will cross the eastern Great Lakes Thursday night,
bringing strong, gusty winds and a period of rain Thursday afternoon
and evening, to be followed by a return to snow behind the cold
front.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of this writing...the expected influx of drier air aloft behind
today`s shortwave has weakened the Lake Erie lake snows even more
than previously anticipated...with just some leftover flurries found
across Niagara/northern Erie counties. Meanwhile the Lake Ontario
lake snows have completed their realignment into a single band
aligned parallel to the long axis of that lake...and continue to
slowly push north toward Watertown where they should be arriving
soon.

Here is what is expected from the lake snows for the rest of
the night...

Off Lake Erie things should remain relatively quiet through about 8
pm or so...with just some flurries/light snow showers primarily
across Niagara/Orleans counties and far northern Erie county. After
that time gradual veering of the low level wind field will re-
establish a longer fetch across the lake...and this coupled with
another brief increase in moisture below 6-7 kft should help to
temporarily re-organize a band of lake snows that will shift
southward across the Buffalo area later this evening and into the
Southtowns/Southern Erie county a little after midnight...with the
lake snows then weakening again and retracting back toward the
lakeshore overnight as moisture decreases and low-level winds
weaken. While this second round of lake snow is not expected to be
as potent as the initial round seen this afternoon...it still
appears likely to produce an additional 1-3" or accumulation as it
redevelops and pushes south across the area.

Off Lake Ontario the band of moderate to heavy snow will lift a
little further north and into portions of the Watertown area early
this evening...then will wobble about between the Watertown area and
the far northern Tug Hill region through the early overnight hours.
The band will then sag a little back further south toward the Tug
Hill during the balance of the night...with it also weakening and
retracting back closer to the lakeshore late as moisture diminishes
and winds weaken. Given better moisture and an upstream connection
to Lake Erie...this band will continue to produce moderate to heavy
snowfall for much of tonight (especially this evening)...with
another foot or so of fresh accumulation falling in the most
persistent snows south of Watertown.

Outside of the above areas...there will be just a few scattered
light snow showers or flurries overnight, with low temps ranging
from 5 to 15 above, and wind chills running in the single digits for
the most part.

Tuesday morning...continued drying and backing of the low level flow
will send whatever is left of the lake effect back northward along
and a bit inland from the lake shores in a much-weakened state...
before these fall apart entirely and/or exit into Canada during the
late morning/midday hours. With moisture thinning to the point where
ice nuclei may be lost within the cloud-bearing layer...the lake
response could potentially end as some freezing drizzle if it
manages to survive long enough.  Quiet weather is then expected
later Tuesday and through Tuesday night with surface ridging nearby.
Not as cold behind the surface ridge for Tuesday and Tuesday night.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
Heading into Wednesday, the next weak trough will slide east across
the eastern Great Lakes supporting a weak cold front to pass across
western and north central New York. Ahead of the frontal passage,
warm air advection will support temperatures to rise above normal.
Additionally associated with the frontal passage, chances for a few
rain showers and higher elevation snow showers, mainly east of Lake
Ontario.

A transient ridge will pass across the region Wednesday night,
supporting another brief period of dry weather. As this ridge rapidly
exits east into the Atlantic, a sharp and progressive mid/upper level
trough will deepen across the middle to upper Mississippi Valley. As
a result a strong (985-990mb) surface low will set up across Sault
Sainte Marie. Ahead of this system, a strong warm air advection
regime will support temperatures to rise up into the upper 40s to
near 50. While model guidance continues to have its differences with
the low`s exact track, overall consensus is for the track east-
northeast across southern Ontario and into southern Quebec by
Friday. This being said, conditions will be windy Wednesday night
through Friday, with the best timing and location for the strongest
winds correlating to the position and how the much the low is
deepening in relation to western and north central New York. This
being said, a 70kt low level jet will slide overhead Thursday night
ahead of the main cold front. While this jet will pass across the
region during the warm sector of the low which will limit the amount
of mixing of higher winds to the surface, the overall set up will
favor downsloping on the north/northwest slopes of the higher
terrain. Outside of the wind potential, chances for rain showers
will arrive Thursday and remain through Thursday night with the
passages of the associated warm and incoming cold front.

Rain will quickly transition back to snow Friday, with the passage
of a secondary cold front pushing south across the region causing
temperatures to tumble back into the 20s. Additionally, gusty winds
will continue to be a factor Friday, with a low level jet of 40-50kt
remaining overhead in the cold air advection regime. This all being
said, the cold air will support a quick hitting, and possibly
impactful lake enhanced/upslope snow event for the end of the week,
especially for east of Lake Ontario.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
A transient ridge and associated warmer air will rapidly shut down
lake enhanced/upslope snows late Friday night into Saturday morning.
The period of quiet weather will be brief, as yet another cold front
will pass across the region Saturday night, supporting a range of 30
degree temperatures to close out the weekend and the start of the
next work week. 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. Cool northwest lingering
on the eastern side of a surface high building east will support the
potential for some lake effect/upslope snow showers south of Lakes
Erie and Ontario.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Remnant lake effect flurries/light snow showers northeast of KBUF
will re-organize and shift southward this evening in tandem with a
temporary increase in moisture and fetch across Lake Erie...with the
redeveloped band likely producing another round of localized LIFR/
IFR conditions as it passes back south across the KBUF terminal
between 02z-05z. The edges of this may also bring some brief MVFR to
KIAG through 03z...and to KROC between about 02z-05z. Overnight the
band will weaken and retract back toward the lakeshore well south of
the KBUF terminal...with diminishing amounts of IFR. The remnants of
this band will then lift northward mainly to the west of KBUF/KIAG
Tuesday morning and dissipate...though will probably still bring
some leftover MVFR ceilings/flurries to the above two terminals.

Off Lake Ontario...moderate to heavy lake effect snow and attendant
LIFR/IFR will affect areas between KART and the northernmost portion
of the Tug Hill this evening...with IFR/LIFR affecting the KART
terminal at times. The band will then slip a little further south
toward the Tug Hill overnight and gradually weaken...before winds
back again Tuesday morning and bring the weakening lake snows back
north across the KART terminal with another round of IFR...before
its remnants finally dissipate north of KART early Tuesday
afternoon.

Outside of the above...conditions will be primarily VFR...with some
MVFR ceilings across the higher terrain of the western Southern Tier
(including at KJHW overnight into Tuesday morning.

Outlook...

Tuesday night...VFR...with some MVFR/higher terrain IFR ceilings
possible across far WNY late.

Wednesday...A period of MVFR/higher terrain IFR ceilings, with a
chance for a few rain/snow showers east of the lakes.

Thursday...VFR deteriorating to MVFR/IFR with rain developing along
with strong southerly winds. Rain changes to snow late Thursday
night along a cold frontal passage. Strong winds veer from southerly
to westerly.

Friday...Becoming all snow with localized IFR in lake effect snow
east/southeast of the lakes. Otherwise MVFR/VFR with scattered light
snow showers. Gusty westerly to northwesterly winds.

Saturday...MVFR/VFR in scattered snow showers.

&&

.MARINE...
A moderate wind flow within small craft advisory range will continue
tonight as a clipper low moves through. Winds will gradually
diminish late tonight through Tuesday, but still remain at or near
Small Craft Advisory criteria.

Another cold front will cross 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 likely 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 until 7 AM EST Tuesday for NYZ001-002-
     010>012-085.
     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...JJR/Thomas
NEAR TERM...JJR/Thomas
SHORT TERM...EAJ
LONG TERM...EAJ/JM
AVIATION...JJR/Thomas
MARINE...Hitchcock/Thomas