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Office: BTV

FXUS61 KBTV 132348
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
648 PM EST Wed Dec 13 2017

.SYNOPSIS...
Cold and blustery conditions are expected overnight into
Thursday before winds abate as high pressure builds into the
region. Thereafter a slow moderation in temperatures is
expected into next weekend with a few snow showers possible.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 648 PM EST Wednesday...Going forecast in good shape with
lingering clouds and light snow over the area...especially north
central and northeast Vermont. Going forecast has this covered
well. Only tweak was to bump current temperatures up a couple of
degrees to match current conditions as cloud cover keeping
temperatures from falling for now. That will change as the night
wears on with clearing skies later tonight.

Previous Discussion...
Overall trends for the next 36 hours will be towards quieter
conditions as a brief ridge of high pressure builds into the
region. Partly to mostly cloudy skies this afternoon will trend
towards a brief period of clearing skies this evening, but will
be short- lived as a weak secondary clipper low passes to our
south after midnight into Thursday morning. Nothing more than an
increase in mid/high clouds overnight is expected, but will
likely have an impact on meteor shower viewing tonight. If
you're planning on braving the bitter cold and winds, the best
shot at clear skies is likely between 10 PM and 2 AM. Make sure
to bundle up as well as lows tonight will range from the single
digits above to single digits below zero with wind chills
falling into the negative single digits to teens.

Thursday starts partly cloudy to the north and mostly cloudy to
the south, but as the aforementioned clipper exits off the
eastern seaboard skies will clear again towards mid-day as high
pressure takes control. The airmass is quite a chilly one with
mean 925-850mb temps in the -15C to -20C range, offering highs
only in the single digits to teens above zero, and lows Thursday
night again in the single digits +/- zero, but winds will be
lighter. Atop the high peaks though, temps Thursday will barely
touch zero, and winds will be brisk in the 20-30 mph range, so
if you're planning on going to enjoy all this great snow we just
got, make sure to bundle up as wind chills will push into the
-20 to -30 below zero range.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 215 PM EST Wednesday...Digging shortwave in broad cyclonic
flow will back flow for favorable SW flow and potential lake
effect banding moving northward into St. Lawrence by Friday aftn
into Friday night ahead of surface clipper/front which after
passage early Saturday morning the band will retreat south
again. The flow indicates longest duration parallel or west of
Route 11 then slipping quickly SE-S as clipper and front push
through.

Our thinking matches closely with WFO BUF and thinking several
inches along-South of Route 3 in Adirondacks with perhaps 3-6+
locally along and West of Route 11 in SW St. Lawrence county.

However...upper shortwave and surface clipper along with moisture
fetch from Lake effect banding will bring about light snow/snow
showers late Friday night - early Saturday especially for northern
NY and mountains of VT. Snow squalls a good possibility along the
frontal boundary Sat morning.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 215 PM EST Wednesday.... Surface clipper and shortwave
moves through NY/VT Saturday morning with some enhanced upslope
flow snows dissipating during the afternoon. Widespread dusting
to less than inch but several inches possible along western
slopes/mountains and an inch-2 in NE VT hilly terrain.

Quiet Sat ngt-Sunday with slight ridging at all levels then backing
return flow will bring about some warm air advection precipitation
Sunday night-Monday. ECMWF and Canadian are in agreement with a more
amplified robust system, still yielding light pcpn whereas GFS is
outlier with continued ridging and nothing. WPC similar to
ECMWF/Canadian thus following these solutions.

Differences continue Monday night-Tuesday as well but at least have
similar thinking of a northern stream shortwave and weak front
moving across in the Tuesday timeframe with perhaps coastal
development after passing our area although GFS sooner/closer with
coastal development and will back off on this solution for now.

Temperatures near freezing with sub-freezing surface layer may mean
some freezing rain as part of the light wintry mix for Monday-
Tuesday.

Temperatures gradually moderating throughout the period with above
freezing highs in the Monday-Tuesday period and slightly cooler
Wednesday.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Through 00Z Thursday...VFR/MVFR ceilings are expected through
about 04z before skies clear and VFR conditions develop for the
remainder of the period. Some mid and high level clouds will
move across the area...but have little impact. There may be some
light snow at KSLK and KMPV through 04z...which may reduce
visibilities into the MVFR category...otherwise VFR visibilities
are expected through much of the period. Winds will be tapering
off through the period with speeds under 10 knots generally
after 12z.

Outlook...

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

&&

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

&&

$$
SYNOPSIS...Lahiff
NEAR TERM...Evenson/Lahiff
SHORT TERM...SLW
LONG TERM...SLW
AVIATION...Evenson