Area Forecast Discussion
Issued by NWS Burlington, VT

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688
FXUS61 KBTV 120528
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
1228 AM EST Tue Nov 12 2024

.SYNOPSIS...
A strong cold front arrives tonight, sweeping from northwest to
southeast across the region bringing gusty northwesterly winds up to
40 mph and a rapid drop in temperatures. A light snow accumulation
is expected early tomorrow morning across the higher terrain, and
some locally icy roads are possible for the Tuesday morning commute.
Thereafter, the weather trends drier and quieter for the remainder
of the work week, with chilly nights and daytime highs primarily in
the 40s.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 934 PM EST Monday...The cold front is currently situated
just north of Montreal and will continue to make steady progress
south and eastward through the overnight hours. Showers have
begun to overspread the region already and period of showers
will continue to be likely through the overnight period as well.
Temperatures are remaining steady while we await the frontal
passage which is slower than previously forecasted. This will
delay the onset of colder air, especially at the higher summits,
which will likely reduce snow totals a bit from what we had
earlier. We have updated the forecast to account for the
anticipated temperature trend and the subsequent precipitation
types and totals.

Previous Discussion...The main feature heading into the
overnight hours will be a strong cold front set to sweep through
the forecast area moving northwest to southeast. This front
will help produce gusty northwesterly winds 20-40 knots with
potentially even up to 50 knots at summits. The front will also
bring with it rapidly falling temperatures as low as 30-40
degrees. For some, this will mean below freezing temperatures
arriving to produce icy road conditions, particularly on
elevated surfaces like bridges as well as mountainous areas
where roads have not been treated. Precipitation associated with
this frontal boundary may freeze with the colder temperatures,
and some minor snow accumulations are also possible. Snow
accumulations into tomorrow morning could reach up to 2-3 inches
at the peaks of the Greens, but around 0.5-2.0" are is expected
elsewhere above 1000 feet. The wider valleys of St. Lawrence,
Champlain, and Connecticut River valleys should have no or trace
snow accumulate.

Efficient atmospheric mixing and strong cold air advection will
produce continued N/NW wind gusts 20-40 knots and again up to 50
knots possible on highest peaks tomorrow. These strong NW winds
contribute to concern for wildfire spread. Precipitation will cut
off by the afternoon hours as sunny skies make their way through our
forecast area. This, however, won`t be enough to counteract the cold
air flowing into the area on the backs of the brisk winds. Despite
very cold temperatures producing moderate relative humidity values,
fire behavior in the drought area of southern Vermont has proven to
thrive in these very dry, windy conditions. Highs will struggle to
reach above the mid 30s to lower 40s on Tuesday, putting us about 5-
10 degrees below seasonal averages. Apparent temperatures are
forecast to remain below freezing from late tonight through the end
of the day Tuesday.

Tuesday night will be even chillier under upper level ridging and
surface high pressure, which will result in clear skies and
decreasing winds. Temperatures are expected to fall into the mid
teens to mid 20s, again 5-10 degrees below climatological normals.
Though temperatures should be too dry and winds just too
elevated/mixed for radiational fog to be a concern, some models are
indicating the potential for low level stratus developing.

&&

.SHORT TERM /WEDNESDAY NIGHT/...
As of 334 PM EST Monday...High pressure will continue to build over
the North Country with some northerly breezes lingering Wednesday
morning. This flow pattern and cool temperature advection will
promote highs and low lower than seasonal averages. Temperatures
will warm into the upper 30s to low/mid 40s and cool overnight into
the teens to lower 20s; mid/upper 20s are expected around Lake
Champlain with influence of warmer lake water. While skies will be
mainly clear, can`t rule out some low clouds over and adjacent to
Lake Champlain from a strong upward moisture flux resulting from
thermal contrast between water and air temperatures. It wouldn`t be
surprising to see some flurries along the lake shore early Thursday.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 334 PM EST Monday...There is a strong model consensus that high
pressure will remain over the region through early Friday keeping
conditions dry with temperatures slowly warming, but still a few
degrees below seasonal averages.

Models begin to diverge from a common solution late Friday into the
weekend with various depictions of how far low pressure off the New
England coast retrogrades northwestward. While the degree of
retrogression is uncertain, consensus is promoting increased shower
chances as moisture wraps around the low and as low level flow
upslopes along the Adirondacks and northern Green Mountains late
Friday and Saturday.

Uncertainty in the upper level pattern increases Sunday onward.
Blended guidance and ensembles favor briefly drier conditions and
increasing southerly flow early next week before the next system can
move into the region. Other deterministic runs are much less
amplified in the Sunday/Monday upper level ridge and would promote
continued shower chances before a front moves through. The current
forecast leans more towards the blended guidance and ensembles which
have verified better recently over the single deterministic
solutions. The result is cautiously optimistic increase in
temperatures Sunday into Monday to around/slightly above seasonal
averages in the upper 40s to around 50 degrees and milder overnight
lows with shower chances increasing again Monday. .

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Through 06Z Wednesday...A sweeping cold front will provide a
resurgence in winds just after 06Z onward with gusts as high as
20-35 knots through at least 18Z. Wind direction will be out of
the northwest following the frontal passage. Ceiling heights
will be on the decrease throughout this 24 hour period as the
cold front comes in, making most sites MVFR around 03Z-06Z
Tuesday due to ceilings 1000-3000 feet above ground level. One
exception will be SLK, which may see IFR ceilings from current
time through 12z. Showers are also expected to increase in
coverage overnight, with best chances for precipitation around
07Z-12Z, depending on the site. Most sites have the potential
for some snow mixing in with rain around 10Z-14Z when
temperatures dip the lowest. This increases the chance for
visibilities to lower to IFR in showers, especially at SLK and
MPV, where snow is most likely. From 12z onward ceilings will be
improving as precipitation comes to an end and high pressure
begins to ridge into the area bringing VFR conditions after 18Z.


Outlook...

Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. Slight chance SHRA, Slight chance SHSN.
Friday Night: Mainly VFR, with areas MVFR possible. Chance SHSN,
Chance SHRA.
Saturday: Mainly MVFR, with local IFR possible. Chance SHRA,
Chance SHSN.

&&

.FIRE WEATHER...
Strong northwesterly winds 15-25 mph with gusts 30-40 mph are
expected Tuesday behind a cold front. Cool temperatures are
expected to keep RH values above critical thresholds, but fine
fuels remain very dry across portions of southern and central
Vermont. This, combined with the gusty winds, will have an
impact on fire weather conditions Tuesday. If any fires were to
start, the weather and fuel conditions could cause fires to
quickly get out of control and be difficult to contain.

&&

.MARINE...
A Lake Wind Advisory has been issued for Lake Champlain tonight
for westerly turning northwesterly winds 15-25 knots sustained
and gusts 35-40 knots across all three sections of the lake.
Wave heights will be in the 3 to 5 feet range tonight into
tomorrow.

&&

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

&&

$$
SYNOPSIS...Storm
NEAR TERM...Clay/Storm
SHORT TERM...Boyd
LONG TERM...Boyd
AVIATION...Neiles/Verasamy
FIRE WEATHER...Team BTV
MARINE...Team BTV