511
FXUS61 KBUF 230535
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1235 AM EST Sun Feb 23 2025

.SYNOPSIS...
Expansive high pressure centered over the Ohio valley will push by
to our south overnight. A westerly flow in the wake of a cold
front will lead to renewed lake snows east of Lake Ontario
into Sunday. Meanwhile, high pressure to our south Sunday and
Monday will support a long awaited and welcomed warmup. In fact,
temperatures will climb to levels that we have not experienced
since last year, the last day of December to be exact.

&&

.NEAR TERM /THROUGH TONIGHT/...
Surface low pressure moving across James Bay sending a cold front
through the area overnight. Low-level winds veering to the west
as moisture advection takes place across the forecast area. A
general light snowfall will move into the region with the front
with some areas seeing just flurries. The main story will be lake
effect setting up east of Lake Ontario where moisture is greater
and the wind field aligns with the long fetch of Lake Ontario.
Snow will begin in Jefferson county late this evening and settle
across the Tug Hill late tonight into Sunday morning. Snowfall
amounts of 4 to 7 inches are expected on the Tug Hill and
western Adirondacks with 2 to 5 inches across Jefferson county.
Snow accumulation should taper off quickly to the south with
less than a inch south of the Oswego River. A Winter Weather
Advisory remains in effect for Jefferson, Lewis, and Oswego
counties. A much weaker response will occur east of Lake Erie,
due to ice cover, warm air advection, and less moisture. A few
elevated locations across Erie, western Genesee, western Wyoming
counties may see 1-2 inches late tonight through Sunday
morning. Temperatures will fall to the teens to low 20s tonight.

High pressure will nose into the forecast area Sunday. An upper
level trough will move east of the region by lunchtime. Warm air
advection will take over and continue through Sunday night. Any
lingering snow showers will come to an end across western NY Sunday
morning. A westerly flow and residual moisture will allow snow
showers to linger east of Lake Ontario through Sunday afternoon,
however snow showers should be fairly light. The Winter Weather
Advisory will come to an end by 1PM Sunday. High temperatures will
reach the low to mid 30s, upper 20s across the higher terrain.

Dry air will move into the region with continued warm air advection
aloft Sunday night. Lows will fall to the low to mid 20s.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
A shortwave that will move from the Upper Great Lakes to the Ottawa
valley will push a warm frontal boundary across our region during
the day Monday. Since the bulk of the associated isentropic lift
will stay north and east of Lake Ontario...mainly dry weather should
be found over the bulk of our forecast area. There will be the
chance for some rain showers over the Eastern Lake Ontario region
though.

More importantly...a 50kt low level jet Monday afternoon will
accompany the approaching mid level shortwave. While the bulk of
these winds will remain aloft within the warm advective pattern...
sfc gusts could reach close to 40 mph at times in the downslope
areas between KIAG and KROC. The winds will also advect notably
milder air into our region with H85 temps forecast to climb to
within a couple degrees of zero C. This will combine with a largely
southerly low level flow to encourage afternoon temperatures to
climb into the mid to upper 40s over the western counties...making
Monday the mildest day since the end of last year (Dec 31). The
widespread snow cover will certainly work against temps from over
achieving...but can certainly still see a few of the normally warmer
valleys tickling the 50 degree mark. Hello Dansville, Mount Morris
and even Wellsville.

In the wake of the mid level energy exiting across Quebec...a fast
moving shortwave ridge will scoot across the region Monday night.
This will support mainly dry weather across the western counties...
but by daybreak Tuesday...a more robust shortwave will be
approaching from the mid western states. While guidance differs on
the speed of this next feature...there should be at least the chance
for some mixed rain or wet snow showers as the night progresses.
Given that mins will be in the low-mid 30s...impactful accumulations
are NOT expected.

An upright mid level trough will become negatively tilted...as it
will cross our region on Tuesday. This should lead to fairly
widespread mixed rain and wet snow showers...although some guidance
packages are leaning towards a drier solution. Given the
`confidence` shown by the Superblend and NBM ensembles...have raised
POPs to likely to categorical throughout the region. Temps are
forecast to climb to within a few degrees of 40...so again...am NOT
expecting this to an impactful event.

Forcing and deeper moisture from the aforementioned shortwave will
exit across New England Tuesday night. This will prompt the mixed
pcpn to end from west to east with little if any accumulations of
wet snow. Temps again are forecast to only drop to the upper 20s to
lower 30s.

A broad low amplitude ridge will build across the Lower Great Lakes
on Wednesday. This will support mainly pcpn free weather with
temperatures that will remain above normal...within a few degrees of
40.

While confidence is growing for unsettled weather Wednesday night...
there is a range of solutions that will have to be considered. The
first being a clean frontal passage with a burst of mixed pcpn that
will end as snow showers...while the second is a wave that will pass
near or over the region with more widespread rain that will end as
wet snow. Have raised pops for this period...but can definitely see
them being raised notably higher in later packages.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
The persistent longwave trough over eastern Canada will evolve into
a deeper full latitude trough over the eastern half of the continent
during this period...and this will eventually lead to us returning
to temperatures that will average well below normal.

A vigorous shortwave will dive southwards from the Upper Mississippi
valley on Thursday...while energy from a previous storm system will
exit across New England. This will place our forecast area between
the two systems and should favor just scattered rain and snow
showers with no real impacts for our area.

A potent mid level trough will pass over the region Thursday night.
This will allow for some nuisance snow showers but nothing that
should have any real impact.

A broad ridge and associated axis of sfc high pressure will move
across the Lower Great Lakes on Friday. This should provide us with
a dry uneventful day with temperatures that will be in the low to
mid 30s.

A deep sub 995mb low will over the Upper Great Lakes Friday night
will move to the Ontario-Quebec border on Saturday. In the
process...a fairly strong cold front wil plow thorugh the region.
This will lead to more mixed rain and snow showers that will be
followed by a return to colder weather to end the weekend.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
As of about 05z...A weak cold front continues to move southeast
through the region. Combined with deeper moisture and west-
southwesterly flow, this feature is generating snow showers across
the area with a couple plumes of lake enhanced snow northeast of the
lakes. Vsbys are VFR to MVFR in most areas and IFR within the lake
effect, with even brief LIFR being observed. Through the remainder
of the night, the two lake effect areas will gradually shift
southward, with the plume off Erie already diminishing in strength
while the one off Ontario intensifies. Confidence in further impacts
to vsbys at KBUF and KART remain low. Regardless, the main focus for
additional accumulating snow will be across the Tug Hill, though
IFR/LIFR vsbys will be possible at KART through at least 12z.

Snow will gradually come to an end in most areas on Sunday as high
pressure builds back in, the main exception south of KART across the
Tug Hill. Low VFR and MVFR cigs are expected to linger through much
of the day, though more substantial breaks in the cloud deck
expected near the end of the 06z TAF cycle.

Outlook...

Sunday night...MVFR improving to mainly VFR. A small chance of light
snow east of Lake Ontario.

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

Wednesday...Mainly VFR.

Thursday...VFR/MVFR. A chance of rain and snow showers.

&&

.MARINE...
High pressure will be centered over the southeast CONUS overnight. A
fresh southwesterly breeze around this area of high pressure will
result in SCA conditions through much of the night.

Winds will begin to relax late tonight, though likely remain
elevated as a weak cold front moves through. Light to modest winds
then expected by Sunday evening, before offshore winds strengthen on
Monday.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory until 1 PM EST this afternoon for
     NYZ006>008.
MARINE...Small Craft Advisory until 6 AM EST early this morning for
         LEZ040-041.
         Small Craft Advisory until 6 AM EST early this
         morning for LOZ042.
         Small Craft Advisory until 6 PM EST this evening for
         LOZ043>045.

&&

$$

SYNOPSIS...RSH/TMA
NEAR TERM...HSK/TMA
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...PP
MARINE...PP/TMA