315
FXUS61 KBUF 171841
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
141 PM EST Mon Nov 17 2025

.SYNOPSIS...
Deep low pressure over the Canadian Maritimes will withdraw
northward across Labrador through Tuesday, while high pressure and
drier air builds east into our region from the Upper Great Lakes.
While this will generally result in lingering lake effect snow
showers diminishing from west to east through Tuesday with only
limited additional accumulations...some localized moderate
accumulations are expected east-southeast of Lake Ontario between
tonight and the first part of Tuesday morning. Weak low pressure
passing by to our south may then bring a few spotty light rain and
snow showers to the Southern Tier Tuesday night...with dry weather
and seasonable temperatures otherwise expected to prevail Tuesday
night through Thursday.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of this writing lake effect snow showers southeast of Lake Erie
have become rather disorganized...while upslope snows east of Lake
Ontario have waned considerably. With only light additional
accumulations expected in both of these areas...the Winter Weather
Advisories for Chautauqua/Cattaraugus and Lewis counties were both
cancelled a bit after noontime.

Deep low pressure over the Canadian Maritimes will withdraw
northward across Labrador through this period...while high pressure
will build east into our region from the Upper Great Lakes. The
resultant lessening of the current cold cyclonic flow and drying out
of our airmass will result in ongoing lake effect snow showers
southeast of the lakes generally diminishing from west to east over
time...though not before an expected temporary uptick in the Lake
Ontario Lake snows produces some localized moderate accumulations
ESE of that lake tonight into Tuesday morning. At the same time...
lingering spottier very light snow/flurries east of Lake Ontario
will also continue to fade...before ending altogether tonight.

Looking a little further at the details of the lake effect...

Off Lake Erie...continued drying and lowering of the capping
inversion will result in ongoing disorganized lake effect snow
showers continuing to gradually weaken/disintegrate into some
remnant spottier light snow showers and flurries this evening...
with the latter then fading out altogether overnight and early
Tuesday. Expect additional accumulations of maybe another inch to an
inch and half out of these through tonight...mainly across the
higher terrain of eastern Chautauqua and Cattaraugus counties.

Off Lake Ontario...lake effect snow showers have shifted a bit
eastward in response to a subtle backing of the low level low and
realignment of the upstream connection to Georgian Bay...with these
now lying primarily across Wayne and Northern Cayuga counties and in
the process of starting to become a bit better organized in response
to the above developments. While marginal surface temperatures
should result in accums from these remaining on the order of an inch
or less through late afternoon...the loss of diurnal influences and
some continued reorganization of the band will likely result in this
producing some localized moderate additional accumulations of 2-5"
from very late today into Tuesday morning across from far eastern
Wayne County across northern Cayuga County. For this reason...a
Winter Weather Advisory remains in effect for these two counties
from 4 pm today through 10 am Tuesday. As we push through Tuesday...
ongoing drying and a lowering cap will then likewise cause these to
also disintegrate into some leftover scattered light snow showers
and flurries...with the remains of these reaching the Tug Hill
region by late in the day as winds turn more westerly.

Outside of the above areas...largely dry weather will prevail
through this period...with lingering brisk northwesterly winds
finally slackening after sunset tonight. Otherwise temps will
continue to average a bit below normal...with lows in the 20s to
around 30 tonight followed by highs mainly in the upper 30s to lower
40s Tuesday.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH FRIDAY/...
A shortwave trough over the Ohio Valley Tuesday evening will move
to the Mid-Atlantic coast by Wednesday morning. Surface low pressure
will take a similar track, however a broad area of high pressure
from the Great Lakes region to the Mid-Atlantic region will weaken
this approaching system. Warm air advection and frontogenesis on
the north side of the surface low will support rain and snow showers
across the northern Ohio Valley into western Pennsylvania, just
south of the forecast area. Light, scattered showers may brush the
western Southern Tier overnight, however probability is low.

High pressure will build into the eastern Great Lakes region
Wednesday and linger across the region through Thursday. This will
support dry and seasonable weather.

An area of low pressure will move across James Bay while it`s
associated cold front will swing through the Great Lakes region
Thursday night through Friday. Meanwhile, a southern stream system
will move from the Southern Plains to the Tennessee Valley. Warm air
and moisture advection head of the advancing cold front will support
rain showers ahead and with the frontal passage.

&&

.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
The Mean 500mb pattern shows a trough moving across eastern Canada
Friday night into Saturday. Cold air advection and lingering
moisture on the backside of an exiting system may support rain and
snow showers across the eastern Great Lakes region through Saturday.
The mean mid-level pattern becomes zonal the end of the weekend into
next week, with no clear signals of forcing for precipitation. Due
to model spread and uncertainty, maintained low chances of showers
Saturday night into Monday.

Temperatures are expected to be below normal Saturday then lean
above normal Sunday and Monday.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
Deep low pressure over the the Canadian Maritimes will withdraw
northward across Labrador through Tuesday...while high pressure will
build east into our region from the Upper Great Lakes. This will
result in lingering brisk northwesterly winds this afternoon finally
slackening after sunset tonight...with lingering lake snows
southeast of the lakes and very light upslope snow east of Lake
Ontario also both generally tending to fade from west to east.

Off Lake Erie...expect lingering disorganized lake effect snow
showers across the Southern Tier to continue to produce localized
IFR/MVFR through early this evening...with both the snow showers and
associated restrictions then diminishing tonight...and eventually
ending altogether Tuesday morning.

Off Lake Ontario...somewhat better organized lake snows and
associated IFR/MVFR will linger across areas well east of KROC
(mainly from eastern Wayne county southeastward into the KSYR area)
through tonight and early Tuesday...before also diminishing and
lifting north toward the Tug Hill during the balance of Tuesday.

Outside of the lingering lake snows...expect general VFR conditions
to prevail across the lower elevations through tonight...with a mix
of MVFR/low VFR found across the higher terrain. Conditions will
then largely improve to VFR in most locations during Tuesday.

Outlook...

Tuesday night...VFR in most areas, with possible MVFR and spotty
light rain/snow showers across the Southern Tier.

Wednesday through Thursday...Mainly VFR.

Later Thursday night and Friday...VFR/MVFR with rain showers likely.

Saturday...VFR/MVFR with a chance of showers.

&&

.MARINE...
Deep low pressure over the the Canadian Maritimes will withdraw
northward across Labrador through Tuesday...while high pressure will
build east into our region from the Upper Great Lakes. This will
result in ongoing widespread Small Craft Advisory conditions
gradually diminishing from west to east tonight through Tuesday,
with much lighter winds then expected through the middle of the week.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Winter Weather Advisory until 10 AM EST Tuesday for NYZ004-005.
MARINE...Small Craft Advisory until 7 PM EST this evening for LEZ020.
         Small Craft Advisory until 1 AM EST Tuesday for LEZ040-041.
         Small Craft Advisory until 7 PM EST this evening for
         LOZ030.
         Small Craft Advisory until 7 AM EST Tuesday for LOZ042.
         Small Craft Advisory until 1 PM EST Tuesday for LOZ043>045.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...HSK
LONG TERM...HSK
AVIATION...JJR
MARINE...Hitchcock/JJR