961
FXUS61 KBUF 211937
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
237 PM EST Fri Feb 21 2025

.SYNOPSIS...
Lake snows will persist this afternoon, especially southeast of
Lake Ontario, before finally ending tonight. Another round of
minor accumulating lake effect snow possible late Saturday night
into Sunday, particularly east of Lake Ontario. Meanwhile, high
pressure moving east from the Ohio valley will set the stage
for a day to day warming trend, with temperatures rising well
above freezing early next week. This warmup will likely be
followed by another prolonged bout of colder weather later in
the week.

&&

.NEAR TERM /THROUGH SATURDAY/...
Lake effect snows continue this afternoon, although bands are
less intense than earlier due to diminishing upstream moisture
and the late February sun angle. There still are moderate to
occasionally heavy lake snows embedded within this, but these
are more localized and cellular. The lake effect snow is still
not being sampled well by radar since most of its formation is
beneath a 4-5k ft inversion so the beam is overshooting the snow
if its more than 50 miles from the radar location.

The snow remains very fluffy with snow to liquid ratios of 40:1
reported at many locations. There won`t be much change in the
conditions through sunset, with perhaps a gradual weakening
trend as temperatures aloft warm from west to east. Between 6
p.m. and midnight, winds will shift from the northwest to the
west, which will cause what`s left of lake effect snows to lift
northward. By this time, warmer air aloft and lowering inversion
heights should finally squash the lake effect snows off of Lake
Erie. Additional accumulations off of Lake Erie will generally
be an inch or less through this evening.

However, off of Lake Ontario lake snows will continue through
this evening, when the band will lift northward more into
Oswego County before the arrival of the 850mb ridge brings an
end to the accumulating snows. Here, an additional 2 to 4 inches
of fluffy accumulation is possible in most persistent snows
which will extend from Wayne to southern Oswego counties.

Tonight will be cold again, with lows mainly in the teens,
except the North Country where a partial clearing will allow
for radiational cooling with lows in the single digits (and
below zero in some colder spots).

Compared to the past several days, Saturday will be a
relatively nice day weatherwise. High pressure to our south will
briefly ridge northward across the region. Highs will mainly be
in the lower 30s, and outside of some lingering morning snow
showers in Jefferson County it will finally be snow-free across
the region. It will be a breezy day, with winds gusting 30 to 35
mph, especially across the Niagara Frontier.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
A surface low over the Hudson Bay earlier Saturday will pivot across
Quebec Saturday night, sliding its associated cold front across the
area due to a passing shortwave trough sliding across the central
and eastern Great Lakes. A head of the feature winds will subtly
veer and moisture will increase supporting a renewed appearance for
lake effect snow showers east of both lakes. While ice cover and
less favorable moisture will help to limit the activity off of Lake
Erie to a few nuisance snow showers however with the open lake and
better moisture to tap into, activity east of Lake Ontario will be
more pronounced. Snow amounts east of the lake will range between 3
to 5 inches with a few higher amounts possible if the lake effect
band becomes more pronounced from late Saturday night into Sunday
morning.

Lake snows will begin to taper off Sunday afternoon as late February
diurnal influences come into play and a flat low-level ridge slides
across the Lower Great Lakes.

A pair of shortwave troughs will slide across the eastern Great
Lakes Monday and Tuesday supporting a surface low over the upper
Great Lakes Monday morning to slide east across the Great Lakes by
Tuesday. With this low, a surface warm front will slide east across
the northern portions of the region Monday. Ample warm air advection
associated with the front will support temperatures to climb into
the low 40s Monday and therefore result in snow to switch over to a
rain/snow mix or plain rain. Chances for showers will linger across
the northern portions of the area Monday night however, with
temperatures dropping to below normal expect rain to switch over to
snow.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Through midweek broad/flat upper-level troughing will remain in
place across our region, with a veritable parade of embedded
shortwave troughs and associated surface waves rotating through this
larger-scale trough and crossing our region in the process. This
will provide us with periodic opportunities for some light to modest
precipitation, along with corresponding shots of warm air advection
that will result in a period of above normal temperatures in spite
of the larger-scale troughing that will be in place. These will
allow daytime highs Tuesday through Thursday to range between the
upper 30s and mid 40s, with lows in the upper 20s-lower 30s Tuesday
and Wednesday nights. The corresponding warmer temperature profiles
should allow any precip from these systems to mix with and/or
largely change over to plain rain in many areas each day, then back
to a rain/snow mix or just plain snow at night.

Late in the period the last of the shortwave impulses looks to at
least partially phase with a deeper northern stream trough digging
southeastward across eastern Canada, resulting in a somewhat
stronger surface low crossing our region Thursday/Friday. The
resulting surface cyclone and increasingly amplified upper troughing
will then circulate another shot of much colder air into our region
for the end of the week, supporting temperatures to fall back to
below average.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Lake effect snows will continue south and east of the lakes
through 00Z, then will lift northward and taper off between 00Z
and 06Z tonight. Snows will generally be less intense, but brief
periods with vsby below 2SM are possible this afternoon at
KBUF/KIAG/KJHW/KROC.

Meanwhile, moisture trapped beneath an inversion will maintain
cigs of 2-4k feet, with mainly MVFR flight conditions through
tonight. Lake effect snows will continue to taper off late
tonight, but the developing southwest flow and lowering
inversion may bring lower MVFR to IFR cigs northeast of the
lakes.

Saturday, southwesterly winds will increase, and this should
finally mix out the moisture trapped beneath the inversion and
allow for VFR flight conditions during most of the day. MVFR
cigs will linger longest at KART. Southwest gusts to 30 knots
possible across the Niagara Frontier.


Outlook...

Saturday night...Snow developing east of the lakes with localized
IFR, mainly east of Lake Ontario. Mainly VFR/MVFR elsewhere.

Sunday...MVFR/IFR in lake effect snow east of the lakes in the
morning, improving to VFR/MVFR late.

Monday and Tuesday...VFR/MVFR. A chance of rain or snow showers.

Wednesday...Mainly VFR.

&&

.MARINE...
Northwest winds will remain elevated across Lake Ontario into
tonight before turning offshore. Small Craft Advisories are in
effect for the southern Lake Ontario shoreline for this period.
Winds will likely remain below SCA criteria across Lake Erie.

Strengthening southwesterly winds will develop Saturday into
Saturday night as a tighter pressure gradient develops over the
lower Great Lakes ahead of the next system. Winds are expected to
remain below gale force, though a round of widespread SCAs are
likely.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory until midnight EST tonight for
     NYZ004>006.
MARINE...Small Craft Advisory until 1 AM EST Saturday for LOZ042>044.

&&

$$

SYNOPSIS...Apffel/PP
NEAR TERM...Apffel/PP
SHORT TERM...EAJ
LONG TERM...EAJ/JJR
AVIATION...Apffel
MARINE...Apffel