Area Forecast Discussion
Issued by NWS Burlington, VT

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FXUS61 KBTV 092335

Area Forecast Discussion
National Weather Service Burlington VT
635 PM EST Fri Dec 9 2016

Scattered snow showers and flurries will continue across the
North Country this afternoon and evening before surface high
pressure builds into the region on Saturday. While drier
conditions are expected to begin the weekend, skies will remain
fairly cloudy with scattered flurries and temperatures running
well below normal. A warm front approaching the area Sunday
night will bring snow back into the region early Monday morning,
likely making for a messy morning commute.


As of 620 PM EST Friday...For the evening update, very little
change. Just some small updates to the cloud cover over the St
Lawrence Valley as the small window of clearing is not
materializing. Beyond that, forecast remains on track with
scattered snow showers continuing, most persistent across the
higher terrain, and temperatures holding steady in the 20s for
most locations under cloudy skies. Winds remain gusty up towards
25 mph making it feel like it`s in the teens. A nice wintry
feeling to end the work week.

For tonight, will mainly be offering a persistence forecast as
mid/upper level flow remains out of the west/northwest combining
with ample low level moisture to continue to produce widely
broken to overcast skies. Should see snow shower activity start
to diminish though as surface high pressure currently moving
into the Ohio Valley approaches, but don`t be surprised to see
some isolated to scattered flurries around, especially along the
higher terrain of the Adirondacks and northern Vermont. With
mostly cloudy skies in the forecast, strong cold air advection
ahead of the approaching high will be hampered some, limiting
temperatures from plummeting too far below seasonal normals.
Should be one of the coldest nights of the season thus far
though with widespread teens in the deeper valleys, and single
digit values elsewhere.

Aforementioned surface high pressure builds into the region
tomorrow with generally partly sunny skies and scattered
flurries around. Temps rebound from chilly morning lows, but
will still top out well below normal only in the upper teens to
mid 20s. Across the higher summits, temps won`t budge out of the
single digits, so if you`re heading to the hills for some fresh
powder make sure to bundle up!


As of 218 PM EST Friday...By Saturday night into Sunday
generally quiet conditions are expected with surface high
pressure being the dominant driver of sensible weather. A
moderately moist, light westerly flow pattern argues for
persistence in this period with partly cloudy skies and perhaps
a few flurries or snow showers, especially across the higher
terrain and to the lee of Lake Ontario across the southern
SLV/western Dacks. Temperatures remain seasonably cold with lows
more or less in the 5 to 15 above range and subsequent highs on
Sunday in the 20s.

By Sunday night our next system is progged to arrive over time as
occluding cyclone across the upper Great Lakes drives strong
moisture and warm occlusion northeast into our region. Thermal
profiles solidly cold enough for all snow, which should arrive in
steady fashion from southwest to northeast over time as robust
isentropic lift in mid-levels interacts with the prime dendritic
snow growth layer. South to southeasterly 925-850 mb flow also
increases sharply during this time (30 to 50 knots) so valley
shadowing effects will be possible at least to some extent with
possible upslope enhancement along eastern facing slopes of the
Adirondacks and Greens. As we draw closer to the event finer scale
detail offered by the higher-resolution models should provide some
additional value. However, a general accumulation of 2-4 inches by
the Monday morning commute seems plausible at this point as
temperatures hold steady, or slowly climb through the 20s.


As of 218 PM EST Friday...Best forcing for precipitation then
swings through and north/east of the area Monday morning through
early afternoon with best moisture advection/isentropic lift
associated with the occlusion. Precipitation will taper off to
very light snow/drizzle and/or freezing drizzle by afternoon as
a pronounced dry slot works in aloft. Some light icing will be
possible across portions of the area during the later part of
the day, mainly across the eastern portions of the Dacks and
eastern VT where sheltered sub-freezing air will be tough to
scour out. Snow totals for the event fairly typical for a strong
warm advective event - generally 3-7 inches with local
variation. Highs on Monday mainly in the upper 20s to lower 30s
in the Dacks and eastern Vermont, with lower to mid 30s in the
Champlain and St Lawrence Valleys.

The remainder of the forecast from Tuesday onward generally features
broad west to northwesterly flow with periodic chances of snow
showers as a large, modified arctic airmass persists across nearly
the entire northern tier of the lower 48. There remains some
disparity among solutions in regard to additional energy ejecting
from the plains states east/northeast along the polar front by mid
to late week and additional chances for steadier snows in our area.
The eventual solution seems to hinge on the degree this energy can
phase with a rather potent polar gyre dropping through central and
eastern Canada, and the extent to which moisture can be drawn back
north atop the polar boundary. Given the current uncertainty will
maintain persistence here capping pops in the chance category as
temperatures start seasonably cold and trend quite chilly by later
next week as modified arctic air continues to bleed south and east
from central Canada.


.AVIATION /00Z Saturday THROUGH Wednesday/...
Through 00Z Sunday...Looking at VFR to MVFR ceilings through the
forecast period. Scattered snow showers will exist through about
18z on Saturday...but visibilities will generally be in the VFR
category. However...any snow showers will have the potential to
briefly reduce visibilities into the MVFR and IFR categories.
West to northwest winds will gradually taper off tonight and
will generally be under 10 knots after 12z on Saturday.

Outlook 00Z Sunday through Wednesday...

00z Sunday through 06Z Monday...VFR under high pressure.

06z Monday through 00z Tuesday...Widespread MVFR cigs and IFR
vsby in light snow.

00Z Tuesday through 00z Thursday...Mix of MVFR/VFR cigs with
scattered snow showers locally reducing vsby to IFR at times,
mainly at KSLK/KMPV.




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