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FXUS61 KBUF 231540
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1040 AM EST Sun Feb 23 2025

.SYNOPSIS...
While some light snow will persist east of Lake Ontario into this
afternoon...high pressure centered over the southern Appalachians
will favor mainly dry uneventful across the region through Monday.
Meanwhile...the same area of high pressure will absolutely guarantee
a long awaited and welcomed warmup through the first half of the
week. In fact, the mercury will reach levels that we have not
experienced since last year, the last day of December to be exact.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
High pressure centered over the Tennesse valley will promote fair
dry weather across the vast majority of western New York this
afternoon...but a sfc trough will pass through the Thousand Islands
and North country to help maintain the snowfall in that area. This
activity has been orographically enhanced to allow for several
inches of accumulation...but as we move through the midday and
afternoon...drier air and a lowering cap will force a diminished
coverage in the snowfall. In fact...this trend of lighter snow can
already be seen on the KTYX radar. Additional snowfall from 11 AM to
nightfall for that area should only be an inch or so...possibly a
bit more on top of the Tug. This should enable the current Winter
Weather advisory for the Eastern lake Ontario region to expire on
schedule at 18z.

A strengthening low pressure system will track out of Manitoba and
across northern Ontario tonight, as high pressure will begin to
shift off the southeast coast and into the northwestern Atlantic.
Guidance is picking up on a wave of moisture aloft within an area of
weak isentropic lift, with a few packages even suggesting some light
flurries in addition to the added cloud cover. Have kept the
forecast dry as this potential seems very low. Otherwise, the setup
will support a southerly flow and WAA across the area, with sfc
temperatures falling back to the low/mid 20s during the first half
of the night before rising through daybreak.

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.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
On Tuesday...the aforementioned shortwave and attendant broader
mid-level trough will make their way across our region. Model
guidance continues to trend toward a more southward track to the
core of the shortwave...which would give us more of a glancing
shot of lift... with this in turn being reflected by an overall
trend toward lighter QPF/drier conditions...though there is
still some disagreement amongst the various guidance packages.
Given the above have backed off somewhat on PoPs for
Tuesday...with generally more scattered pcpn expected save for
areas east of the lakes...where a boost from upsloping may still
allow for a better likelihood of some mixed rain/wet snow
showers. Otherwise highs will range from the upper 30s across
the higher terrain to the lower 40s across the lower
elevations...where conditions should remain warm enough to allow
for any pcpn to again fall in the form of plain rain.

Following the passage of these features...an elongated ridge of high
pressure and drier air will result in a west-east return of drier
weather later Tuesday...Tuesday night...and for at least the first
half of Wednesday. While a bit lower than those of the night
before...lows Tuesday night will still be mild for this time of year
(upper 20s-lower 30s)...with highs on Wednesday then again climbing
back into the lower to mid 40s in most places out ahead of the next
mid-level trough and its attendant surface wave. This next system
could bring a few rain showers into the far west as it approaches
later Wednesday afternoon...however the better potential for pcpn
looks to follow for Wednesday night as this system works directly
into our region. Given increasing model agreement on this
scenario...have bumped PoPs up into the high chance/low likely range
for Wednesday night...with the mild airmass out ahead of this system
supporting mainly rain. The exception to this will be across the
North Country...where cooler temperature profiles may support snow
or a rain/snow mix.

&&

.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.

Digging further into the forecast details...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 these
two systems and should favor just scattered rain and snow showers
with no real impacts for our area.

A potent mid level trough will then pass over the region Thursday
night and early Friday. This may help to generate some additional
nuisance snow showers (which may be orographically enhanced east of
the lakes)...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 mainly dry and uneventful day...along with high temperatures
mainly running in the lower to mid 30s.

A deep sub 995mb low will over the Upper Great Lakes Friday night
will move to western Quebec by later Saturday/Saturday night. As it
does so... it will pivot a fairly strong cold front across the
region sometime between Saturday and the first half of Saturday
night. This will lead to more mixed rain and snow showers...followed
by a return to notably colder weather to end the weekend and start
the following work week.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
Surface high pressure across the southeast states will build north
across the Lower Great Lakes through the day. A chilly airmass,
lingering moisture and WNW flow above 1000ft are directing a few
light snow showers with VFR/MVFR vsbys into western NY. These will
continue to diminish through the course of the morning, though cigs
of 2000-300ft will likely persist through the afternoon.

A different situation east of Lake Ontario where snow is much more
widespread and MVFR/IFR vsbys more commonplace. Coverage and
intensity of these snows will also diminish through the morning,
though likely focus south of KART over the Tug Hill Plateau instead
of completely tapering off. Cigs east of the lake will be mainly
MVFR, with IFR over the Tug.

A few flurries will be possible tonight, mainly east of Lake
Ontario, though otherwise a slow improvement from MVFR cigs to VFR
is expected from west to east.

Outlook...

Monday...Mainly VFR. Breezy south to southwesterly winds with gusts
to 35kts possible, especially at KBUF/KIAG.
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 across the southeast states will support a modest
southwesterly breeze across the lakes through much of today. Winds
will very gradually subside through the course of the day, though
remain elevated enough on Lake Ontario to warrant continuing the
current SCAs through the afternoon.

Offshore winds will increase and shift southwesterly on Monday as a
low pressure system tracks far to our north. This will likely
warrant a new round of SCAs on both lakes into Monday evening.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory until 1 PM EST this afternoon for
     NYZ006>008.
MARINE...Small Craft Advisory until 6 PM EST this evening for
         LOZ043>045.

&&

$$

SYNOPSIS...RSH
NEAR TERM...PP/RSH
SHORT TERM...JJR
LONG TERM...JJR/RSH
AVIATION...PP
MARINE...PP