Williston, Vermont 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

957
FXUS61 KBTV 241204
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
704 AM EST Sun Nov 24 2024

.SYNOPSIS...
A breezy, upslope pattern will continue through tonight,
supporting several inches of wet mountain snow in the northern
Greens and blustery conditions as temperatures trend colder.
After a quiet day on Monday, rain is expected on Tuesday which
may begin as freezing rain in some areas. A potentially more
significant winter storm may follow for the Thanksgiving
holiday.

&&

.NEAR TERM /THROUGH MONDAY/...
As of 704 AM EST Sunday...Forecast is in good shape, although
some changes were made. The dry westerly flow has proven to be
more effective than expected at scouring moisture, resulting in
both greater coverage of clear skies and lighter precipitation
where snow showers are occurring. Little measurable
precipitation has been observed in the Adirondacks over the last
couple of hours; have collaboratively matched NWS Albany in the
southern Adirondacks with lower PoPs this morning. Meanwhile,
based on satellite imagery, cloud depths in northern Vermont
along and east of the Green Mountains appear a bit deeper to
maintain higher PoPs. Snow amounts may need to be reduced a bit,
but will let it play out with chances for enhanced moisture
later in the day that would help increase precipitation rates.

Previous Discussion...
Today we are in a classic high froude number winter scenario,
where strong westerly flow has developed with cold air advection
occurring and sufficient low level moisture for precipitation.
This pattern is favorable for significant snowfall along the
spine of the northern Greens as well as seeing snow showers
across much of northeastern Vermont. Temperatures are expected
to cool this morning such that snow levels, which have been
marginal for snow overnight, will lower to allow snow to be the
primary precipitation type across the region for much of the day
before precipitation tapers off. Additional snowfall of 1 to 2
inches will be possible across much of this area with locally 2
to 4 inches of snow, and up to 9 inches at the highest summits.
Snow character will tend to be wet but increasingly dry, so some
blowing/drifting of snow may be possible given the gusty winds
in excess of 25 MPH at times today. Little or no snow is
expected west of the Green Mountains and precipitation will be
minimal in the southern Greens today with limited moisture.

Increasingly quiet weather follows tonight through Monday with
seasonable weather and no precipitation. Given partial clearing
and a seasonably cold air mass, temperatures will be as cold as
we have seen in several days with morning temperatures as low
as the 20s areawide. As weak high pressure moves overhead during
the day on Monday, winds will trend light.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
As of 330 AM EST Sunday...Areas of light freezing rain are possible
early Tuesday morning as a frontal system and associated mid-level
shortwave trough approaches from the eastern Great Lakes. Potential
ice accumulation Tuesday morning will be focused across
central/eastern VT and a few sheltered locations within the northern
Adirondacks with ice accumulations generally <0.05". With that said,
even minimal ice accumulation can pose a significant hazard for
motorists and pedestrians, especially early in the season when many
paved surface have yet to be chemically treated. Precipitation
arrives by daybreak and temperatures should warm by late Tuesday
morning...so the primary threat for icy roads will be between 10-15Z
(5am and 10am) based on current indications. With south winds, it
appears temperatures will be above freezing in the Champlain Valley
before precipitation arrives, so again, potential for icy roads will
be focused east of the Green Mtns in Vermont. Will continue to
monitor for possible Winter Weather Advisory as we get closer.

Maximum PoPs on Tuesday near 90 percent as cold front and associated
forcing moves through our region during the mid-morning thru early
afternoon hours. Afternoon temperatures should reach the low-mid 40s
before onset of westerly wind shift and low-level CAA later in the
afternoon into the evening hours. With low-level CAA, residual
cyclonic mid-level flow, and moisture advection from the Great
Lakes, do expect continued cloudy skies and scattered snow showers
through Tuesday night. Snow showers should be most prevalent in the
northern Adirondacks aided by orographic ascent. A dusting to 2" of
snowfall is possible Tuesday evening thru Tuesday night associated
with light snow shower activity, with the higher totals expected in
the mountains of northern NY and northern VT. Low temperatures
Tuesday night will generally fall back to the 25-30F range.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 330 AM EST Sunday...We continue to monitor a potential
Nor`Easter for Thanksgiving Day into Friday which could bring snow
and difficult winter travel conditions during the busy holiday
travel period. In advance of this system, weather conditions will be
relatively quiet Wednesday into Wednesday night with scattered light
rain/snow showers on Wednesday associated with moisture advection
from the eastern Great Lakes (PoPs 30-40% during the daylight hrs on
Wednesday). Also anticipate considerable lake generated low-
level/stratus clouds given trajectories from wrn NY and sern
Ontario. Most of the snow shower activity should diminish after
sunset on Wednesday. Highs on Wednesday will range from the mid 30s
across the northern Adirondacks and far nern VT, to the upper
30s/lower 40s elsewhere. Lows will mainly be in the mid-upper 20s
Wednesday night, though some lower 20s are possible if any
significant breaks development in the cloud cover.

Still considerable spread in 00Z NWP deterministic and ensemble
guidance for Thursday into Friday, as would be expected in the Day 4-
5 time range. With that said, the 00Z deterministic ECMWF, 00Z
Canadian and 18Z GFS were all in line with deepening coastal low
developing in vcnty of the Delmarva peninsula/NJ coastline at 18Z
Thursday with system tracking to near Cape Cod by 06Z Friday. Track
of these models is particularly favorable for widespread wintry
precipitation Thanksgiving afternoon into early Friday morning,
though absence of cold sfc anticyclone to the north suggests a mix
of wet snow and periods of possible mixed precipitation or rain in
the valleys. At this early stage, it`s also quite possible that the
00Z GFS solution materializes, with a less amplified mid-level flow
pattern and a weaker low pressure system remaining to our south. At
this time, have indicated 60% PoPs late Thursday/early Friday for
snow and periods of mixed pcpn/lower elevation rain. Difficult/slow
winter travel conditions are possible. Bottom line is that those
with holiday travel plans Thursday aftn/Fri will want to keep a
close eye on the forecast as mesoscale details become more apparent
in the coming days.

Brisk conditions will follow with a moderately strong northwesterly
flow as low pressure system departs across the Canadian
Maritimes/Gulf of St. Lawrence late Friday into Saturday. Should see
highs in the upper 20s to mid 30s for Saturday with periods of snow
showers, especially across the higher elevations of nrn NY and VT.
High temperatures for the weekend should be just slightly below the
30-year climo average for late November.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Through 06Z Monday...A mix of MVFR and VFR will prevail across
the region over the next 24 hours, with MVFR ceilings most
likely to continue at the higher elevation sites - SLK, EFK, and
MPV. Air has been drier than expected limiting snow to mainly
flurries so no visibility restrictions are expected at the
aforementioned terminals where snow is possible. Greatest
chances of precipitation appear to be between 17 and 18Z at SLK,
19 and 21Z at MPV, and much of the day at EFK. West winds will
continue to occasionally gust 15 to 25 kts, with a few higher
gusts possible during the day, before tapering off tonight.


Outlook...

Monday: VFR. NO SIG WX.
Monday Night: VFR. Chance RA, Slight chance FZRA.
Tuesday: Mainly MVFR, with local IFR possible. Definite RA,
Likely FZRA.
Tuesday Night: Mainly VFR, with areas MVFR possible. Chance SHSN,
Chance SHRA.
Wednesday: Mainly VFR, with local MVFR possible. Chance SHSN,
Slight chance SHRA.
Wednesday Night: Mainly VFR, with areas MVFR possible. NO SIG WX.
Thanksgiving Day: Mainly VFR, with local MVFR possible. Chance
SN, Chance RA.

&&

.MARINE...
Strong westerly winds have developed over Lake Champlain early
this morning. Both the northern waters and broad lake are
seeing sustained winds near 25 knots with higher gusts.
Conditions will remain fairly consistent through the day with
winds more markedly tapering off tonight. Wave heights should be
2 to 4 feet, with largest wave action over Burlington and
Shelburne Bays given the favorable wind direction/largest fetch.

&&

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

&&

$$
SYNOPSIS...Kutikoff
NEAR TERM...Kutikoff
SHORT TERM...Banacos
LONG TERM...Banacos
AVIATION...Kutikoff
MARINE...WFO BTV