Williston, Vermont 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

366
FXUS61 KBTV 111943
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
343 PM EDT Fri Apr 11 2025

.SYNOPSIS...
A mix of rain and snow will overspread much of Vermont and the
eastern Adirondacks by Saturday morning. A winter weather advisory
is in effect for portions of central and southern Vermont for 2 to 6
inches of snow and localized slick travel. A cool and damp Saturday
is expected with temperatures only warming into the mid 30s to mid
40s, except mid 50s across the St Lawrence Valley. Drier and
slightly warmer conditions are expected on Sunday.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
As of 339 PM EDT Friday...Winter weather advisory from 5 AM to 5 PM
Saturday for 2 to 6 inches of snow, mainly above 1000 feet across
portions of central/southern Vermont.

A highly elevational dependent snowfall is expected on Saturday
across portions of central/southern VT and parts of the eastern
Dacks, with a slushy coating valleys to 4 or 5 inches in the
higher terrain, given marginal temp profiles. Areas outside the
higher precip rates wl see very limited snowfall accumulation,
as rain wl be primary ptype.

GOES 19 water vapor shows deep full latitude mid/upper lvl trof acrs
the eastern CONUS, with potent s/w energy enhancing sfc low pres
over eastern NC. This s/w energy and nose of a 250mb jet of 100
knots is helping to produce favorable synoptic scale ascent and
cooling cloud tops over the mid Atlantic States per latest GOES-19
imagery. Given the deep southerly 700mb to 300mb southerly flow this
conveyor of moisture wl advect northward into our cwa overnight into
Saturday morning.

These deepening and closing off cyclonic circulations are always
challenging with regards to how far the band of moderate to heavy
precip lifts northward before dissipating and associated impacts.
Crnt trends have been for a deeper closed circulation, which
captures sfc low pres and hangs it along the coast for a longer
period of time on Saturday. This scenario has resulted in a slight
northward shift in the axis of heavier precip on Saturday acrs our
cwa. If trends continue advisory may need to be expanded to
include Washington, Lamoille and Caldonia counties.

This scenario produces a ribbon of very strong 700mb fgen forcing
lifting from south to north acrs our eastern Dacks into VT zns btwn
12z and 18z Sat, along with deep uvv`s fields supporting high precip
rates. Its within this band of moderate to heavy precip, the column
wl become isothermal near 0C to support a change to heavy wet snow
for a period of time on Saturday. Dynamical cooling combined with
easterly 925mb to 850mb flow wl help cool bl temps just enough to
support snow, especially above 1000 feet on the eastern side of the
Greens and parts of the eastern Dacks. Did note HREF highlighting
central/southern VT zns with 1 hourly snowfall rates of 0.50 to 0.75
on Sat morning, within this band. Elsewhere a few wet flakes could
mix with the heavier band of precip in the deeper valleys, but
sounding data shows bl temps btwn 34-38F. Did tweak snow ratios from
4/6 to 1 valleys to 10/12 to 1 mtn summits in advisory area on
Saturday, to sharp elevational dependent snowfall gradient.

As band of heavier precip shifts northward, conditions wl improve
quickly from south to north acrs our region with temps warming into
the mid 30s to mid 40s, except mid 50s SLV, where limited precip is
anticipated. Areas of slick travel wl be mainly above 1000 ft on
Saturday morning with conditions quickly improving by noon time,
given the high mid April sun angle. Given the heavy wet nature of
snowfall, a few isolated power outages are possible, where
accumulations reach 4 inches or so.

We continue in cyclonic flow on Saturday night but forcing is weak,
while deep layer moisture is located over most of VT. Areas of
drizzle and light rain is possible, as sounding data shows rh values
near 100% below 800mb. Expect plenty of low clouds obscuring the
trrn with areas of light precip, especially favorable east/northeast
upslope areas of the Green Mtns. Temps with clouds hold in the mid
30s to lower 40s.

&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 339 PM EDT Friday...Low pressure will continue tracking
northeastward along the New England coast Sunday. Blended global
guidance doesn`t favor much in the way of additional rain chances,
but CAMs favor an impulse wrapping around the backside of the low
during the day on Sunday before completely ejecting into the
Canadian maritimes. Since we are moving more into the mesoscale
guidance window, added some slight chances of rain wrapping back
along the Greens and eastern Vermont. No appreciable impacts are
expected, but could affect people with plans on recreating outdoors.
While flow will be northerly, the incoming airmass will be hybrid
maritime moving around the low`s periphery rather than Canadian
continental. This will keep temperatures warmer with highs in the
50s, except some 40s along/east of the greens where isolated rain is
possible. Overnight, conditions are favored to become drier with
high pressure moving in. Lows. are expected to cool into the upper
20s above 1000ft in northern New York and in the 30s elsewhere.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 339 PM EDT Friday...Overall pattern evolution next week in
ensembles and deterministic models is favored to remain somewhat
progressive with moderate amplitude longwave pattern. This means
that no blocking is anticipated, and a regular transition from
ridge-trough-ridge-trough is anticipated through the work week.
Current timing puts precipitation windows late afternoon Monday
through Wednesday and again late Thursday night into early Saturday.
As such, Monday will be the pick of the week for outdoor plans with
temperatures warming into the 50s to low 60s. Tuesday onward, a
moderate pressure gradient will support breezes for much of the
remainder of the week and high temperatures oscillating in the 40s
to 50s. Overnight periods coincident with precipitation will allow
for some snow showers mainly in higher terrain, except for Wednesday
where cooling will support some snow showers for some broader
valleys.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
Through 18Z Saturday...Plenty of clouds continue to prevail
across our taf sites this afternoon with a combination of
MVFR/VFR cigs and VFR vis. Cigs heights will slowly increase
this afternoon, before falling again tonight with IFR cigs
redeveloping at MSS associated with low level moisture on
northeast flow. Also, have to watch lowering cigs to potential
IFR at MPV with easterly upslope flow tonight. Otherwise, mostly
VFR conditions at BTV/PBG with MVFR cigs at EFK/SLK thru this
evening with south/southeast winds 5 to 10 knots, except
northeast at MSS. A mixture of rain/snow develops toward 12z
Saturday with IFR vis likely at MPV and at times at RUT/SLK,
while MVFR vis/cigs prevail at the rest of our sites.

Outlook...

Saturday Night: Mainly MVFR, with local IFR possible. Slight
chance SHRA.
Sunday: Mainly MVFR, with local IFR possible. NO SIG WX.
Sunday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Monday: VFR. NO SIG WX.
Monday Night: Mainly VFR, with local IFR possible. Likely SHRA.
Tuesday: Mainly VFR, with local IFR possible. Likely SHRA.
Tuesday Night: Mainly MVFR, with local IFR possible. Chance SHRA,
Chance SHSN.
Wednesday: Mainly MVFR, with areas VFR possible. Chance SHRA,
Chance SHSN.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Winter Weather Advisory from 5 AM to 5 PM EDT Saturday for
     VTZ010-018>021.
NY...None.

&&

$$
SYNOPSIS...Taber
NEAR TERM...Taber
SHORT TERM...Boyd
LONG TERM...Boyd
AVIATION...Taber