FXUS61 KBTV 251357
Area Forecast Discussion
National Weather Service Burlington VT
857 AM EST Mon Jan 25 2021
Temperatures will begin to moderate today and conditions will be
dry with high pressure passing overhead. A low pressure system
moving through New York will bring some light snow to the area
late Tuesday through midday Wednesday. Some snow showers will
linger over the higher terrain into Thursday. Temperatures will
drop to below seasonable norms Friday and Saturday.
.NEAR TERM /THROUGH TUESDAY/...
As of 857 AM EST Monday...Quick update to the forecast for
today to adjust clouds, temps and wx based on current obs. Cloud
cover across northern New York is advancing quickly eastward
and developing along and east of Lake Champlain in the northern
Champlain Valley. Expect clouds to continue to spread and
thicken with partly to mostly cloudy skies for the remainder of
the day from the Champlain Valley westward, while to the east
and south more sun will be seen. In addition, area webcams
across the Adirondacks show some flurries so have added that
back into the forecast for areas where cloud cover will be
thickest today. No changes made beyond today`s forecast for now.
Previous discussion...Today and tonight will be relatively
quiet on the weather front with high pressure slowly moving
northeastward over our forecast area. Temperatures will begin to
moderate starting today as the high shifts to eastward. Highs
today will be in the upper teens to mid 20s...a good 10 degrees
above yesterday`s highs for much of the area. For tonight, still
expecting some mid and high clouds to spread over the area that
will limit diurnal heat loss. In addition, forecast soundings
are indicating some of the higher terrain will have low clouds
persisting tonight. Thus, despite high pressure over the region,
thinking overnight lows will generally stay above zero, and up
to the low teens in the valleys.
Temperatures will continue to moderate Tuesday as a low pressure
system tracks to western NY, sending a warm front towards our
forecast area. Pretty much all of the model guidance has taken a
northward shift in this low pressure system that was previously
expected to stay to our south. Thus, Tuesday/Tuesday night forecast
has changed for the North Country, and snow lovers will embrace the
change since this shift does bring some snow (albeit relatively
light) into the area. Snow will spread over northern NY late Tuesday
afternoon, moving north and eastward into the evening hours. See
Short Term Discussion for more details on this snow event.
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY/...
As of 235 AM EST Monday...A period of accumulating snows
appears likely Tuesday night into Wednesday morning as weakening
low pressure lifts into the region. Warm advection processes
and modest isentropic lift through the mid- levels (around 290K)
will will be the main players here, with strongest forcing
setting up across southern Adirondacks into Essex County, NY and
across our southern VT counties. That said, the primary
dendritic snow growth zone generally lies above the area of best
lift, boosting confidence that this will largely be a light
snowfall event. I leaned heavily toward a model-blended solution
in regard to QPF, downplaying this morning`s GFS contribution
with it`s typically biased higher amounts under weak/modest WAA
events. Steadier light snows then become more amorphous and
lessen in overall coverage into Wednesday afternoon as warm
thermal advective processes wane. Early snowfall total estimates
from late Tuesday afternoon through noon Wednesday or so will
average generally in the 1-3 inch range, with slightly higher
amounts from 2-5 inches across Essex County, NY and
Windsor/Rutland counties in VT. With an abundance of clouds and
light near-surface winds temperatures will show a smaller than
normal diurnal range through this period, averaging generally
from the mid teens to lower 20s Tuesday night, and in the 20s on
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 235 AM EST Monday...Lingering light snow and/or snow
showers continue to wane into Wednesday night/Thursday, with
best coverage across the eastern higher terrain where some minor
additional accumulations will be possible. Forcing is quite
weak however so nothing too notable by late January standards.
The primary feature during the late week time frame will be a
fairly impressive arctic shortwave trough forecast to dive
southeast through the area Thursday evening into Friday morning
which will usher in a much colder airmass for Friday into
Saturday. With the arrival of this feature expected at night,
the threat of more organized squalls appears rather low at this
point, but at least some lower-end PoPs will be maintained to
account for the cold frontal passage. Highs on Thursday near
seasonal values in the upper teens to mid 20s in nrn NY and
through the 20s in VT, then considerably colder Fri/Sat (single
digits and teens).
Looking further out there is some indication that another round of
accumulating snows will occur by Sunday night or perhaps on Monday
as temperatures moderate ahead of a rather complex system advancing
east from the Great Lakes.
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
Through 12Z Tuesday...Mainly VFR conditions expected through 06Z
with light and variable winds. The only exception will be KSLK,
where some MVFR ceilings are currently being reported and are
expected to remain through 23Z before lifting some to VFR
levels. Otherwise, will see some bkn/ovc ceilings between 2000
and 3000 ft spread over much of the area between 06Z and 12Z.
Tuesday: VFR. Chance SN.
Tuesday Night: Mainly MVFR, with areas VFR possible. Chance SN.
Wednesday: MVFR. Chance SN.
Wednesday Night: Mainly MVFR, with local IFR possible. Chance
Thursday: Mainly MVFR, with local VFR possible. Slight chance
Thursday Night: Mainly VFR, with areas MVFR possible. Slight
Friday: VFR. Slight chance SHSN.