-- Discussion containing changed information from previous version are highlighted. --
398
FXUS61 KBTV 130600
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
100 AM EST Mon Jan 13 2025

.SYNOPSIS...
After a mostly sunny and mild day across the region today, we will
see conditions begin to trend colder and snowier as we enter the
next work week. Snow showers are expected ahead of a cold front
Monday afternoon and evening with some lake effect snow possible
across St. Lawrence County Monday night into Tuesday. Another long
duration upslope snow event looks likely Tuesday into Wednesday
before quieter weather descends across the region on Thursday.

&&

.NEAR TERM /THROUGH TUESDAY/...
As of 1229 AM EST Monday...Forecast is mostly in good shape.
Some substantial changes to precipitation in the very near term,
with higher PoPs needed based on surface observations. Top-down
moistening seems to have been sufficient to combine with
isentropic lift for light snow across western portions of
northern New York, with several ASOS showing snow and
visibilities near 2 miles. For a given location maybe only an
hour or two of steady snow will fall, but it will be enough to
have a tenth or two tenths of an inch of accumulation in a
larger area than previously forecast for tonight. As you go
eastward, the duration of virga and lowering clouds sufficient
for snow to reach the ground becomes more uncertain, but brief
snow could push through all of northern Vermont in the early
morning hours.

Previous discussion...For many, today it`s been a seasonally
mild day with plenty of sunshine. However, for portions of the
Northern Adirondacks, it`s been anything but mild or sunny.
Subsidence associated with low level and mid level high pressure
has been a blessing and a curse as it`s kept moisture away from
Vermont but trapped across northern New York. The good news,
however, is that the latest satellite imagery shows these clouds
beginning to fizzle out but it likely won`t be until after
sunset that we see clearer skies across that area. We will
continue to see clear (or clearing skies across NY) through the
evening hours but mid level clouds will quickly overspread the
region after midnight as a warm front begins to lift towards the
North Country. We will see the warm front move into New York
around sunrise on Monday and into Vermont shortly thereafter. As
winds shift to the south, we will see some warm air advection,
although rather minor in the grand scheme of things. This will
allow temperatures on Monday to warm into the upper 20s to mid
30s while winds could gust up to 25 mph.

A cold front will quickly move into New York during the early
afternoon hours and bring a round of snow showers to the North
Country. The latest high-res guidance shows that we could see
upwards of 75-100 J/kg of CAPE in the afternoon, boundary layer
winds up to 30 knots, and weak frontogenesis. The combination of
these ingredients will likely yield some convective snow showers and
potentially even a snow squall or two. The timing of these snow
showers will likely coincide with the evening commute across New
York which could create reduced visibilities. Given temperatures
will warm above freezing a few locations tomorrow, the potential for
a flash freeze in the wake of the snow showers cannot also be ruled
out. For Vermont, the forcing is expected to weaken as the front
moves into Vermont while the instability will also wane given the
time of day. Snow showers remain possible for Vermont but are less
likely and will be less intense. Lake effect snow will begin to move
into southern St. Lawrence County in NY Monday night with 1-3 inches
of snow likely through Monday night.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
As of 248 PM EST Sunday...Westerly cyclonic flow continues through
the day on Tuesday. Some moisture off Lake Ontario looks to get
transported into northern New York, but any significant banding
should stay to the south. Snow showers will fall in parts of the
Adirondacks and northern Greens but accumulations should be
relatively light. The Champlain Valley will likely be downsloped and
not receive much of anything. Relatively unblocked flow should also
keep most of the snow showers above the western slopes. The flow
becomes northwesterly Tuesday night, and it becomes moister and
moire blocked. This will reinvigorate the upslope snow showers and
they should become widespread in the northern Greens and northern
Adirondacks where several inches are expected. Flow should
eventually become more blocked, so the western slopes and Champlain
Valley should be able to get into some snow showers as well. A
saturated DGZ with lift will allow for dendrites and efficient
accumulations. The snow showers become lighter and less widespread
as Wednesday progresses, but they look to linger a bit into
Wednesday night in the most favored areas. While the upslope looks
similar to last week on Wednesday morning, the duration will be much
shorter.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 248 PM EST Sunday...Drier conditions look to prevail for the
end of the week, though a few snow showers are possible as a weak
disturbance moves through. Southwesterly flow develops for Friday
into Saturday, and it looks to briefly send temperatures above
freezing in the broad valleys for Saturday. A potent cold front
looks to pass through Saturday night and bring some precipitation
with it. Due to the above freezing low- levels, it may start briefly
as rain there before switching to snow. However, any precipitation
with this front looks to be on the lighter side. A low will try to
develop along this front after it has passed to the south and could
bring more significant snow, but there is large model spread. The
only area of agreement is that this low would likely develop to our
south so any of this heavier precipitation would likely be snow
everywhere. Behind this storm, temperatures will be sharply colder
and it could be the first arctic airmass of the season.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Through 06Z Tuesday...VFR ceilings will generally lower to MVFR
ceilings 2000-3000 ft agl as brief -shsn moves from west to
east from 07-11Z. Visibilities could fall to 2SM at KMSS and
KSLK under more moderate snowfall, otherwise most visibilities
at KPBG and Vermont locations will trend towards MVFR
conditions. A brief respite in the snow showers between 11-14Z
could lend a return to VFR conditions across most TAF sites.
More widespread snow showers return by 14Z reducing ceilings
back towards MVFR conditions through 00Z. Winds will generally
be light and variable with winds and gusts increasing to 5-10
knots sustained and 10-20 knot gusts at KMSS and KSLK by 18Z.


Outlook...

Tuesday: Mainly VFR, with local MVFR possible. Chance SHSN.
Tuesday Night: Mainly VFR, with areas MVFR possible. Chance SHSN.
Wednesday: Mainly VFR, with local MVFR possible. Chance SHSN.
Wednesday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Thursday: Mainly VFR, with local MVFR possible. Chance SHSN.
Thursday Night: Mainly MVFR, with areas VFR possible. Slight
chance SHSN.
Friday: Mainly VFR, with areas MVFR possible. NO SIG WX.
-- End Changed Discussion --

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...Clay
NEAR TERM...Clay/Kutikoff
SHORT TERM...Myskowski
LONG TERM...Myskowski
AVIATION...Danzig