Area Forecast Discussion
Issued by NWS Burlington, VT-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KBTV 012326
Area Forecast Discussion
National Weather Service Burlington VT
626 PM EST Thu Dec 1 2016
A closed upper low over southern Quebec will keep the north
country in cyclonic flow through Saturday, with cloudy skies and
chances for rain and snow showers from tonight through Saturday.
A ridge of high pressure will build into the region on Sunday,
with fair and dry weather expected from Sunday through Tuesday.
.NEAR TERM /THROUGH FRIDAY/...
As of 602 PM EST Thursday...The closed upper low over
southwestern Quebec will keep the North Country in a moist,
cyclonic flow regime overnight. Prevailing SFC-800mb flow will
continue from the WSW overnight into Friday...which will be
favorable for upslope snow shower activity in the nrn
Adirondacks and central/nrn Green Mtns, but not offer much in
the way of low-level CAA with trajectories coming from the open
waters of the ern Great Lakes. Will continue to see passing
light rain showers in the valleys, with more frequent rain/snow
shower activity across the higher elevations of the nrn
Adirondacks and central/nrn Green Mtns. At 23Z, seeing light
snow at KSLK, and generally above 2000ft in the nrn Greens.
Should see snow levels fall to 1000-1500ft during the late
evening and overnight hours, with a coating to 2" possible above
1500ft or so overnight. Meanwhile, in valley locations, the
combination of cloud cover and west-southwest winds will help to
keep temperatures above freezing overnight. MOS guidance looks
too cold for overnight min temperatures, so have leaned toward
the warmer GFS LAMP mos guidance for min temperatures overnight.
Winds will stay up overnight and this combined with the cloud
cover will keep temperatures several degrees warmer than MOS
On Friday, the North Country will continue to be under the
influence of the closed upper low over southern Quebec which
will keep in cloud cover, along with chances for rain and snow
showers. Snow showers will be mainly confined to the higher
elevations of the Adirondacks and Green Mountains where
additional accumulations of 1-3" are possible for the higher
summits of nrn NY and VT. Highs will be mainly in the low- mid
40s on Friday, except locally in the mid- upr 30s for the nrn
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 311 PM EST Thursday...500mb trough moves through the
region Friday night with snow showers expected about 1000ft and
above and rain/snow mix at lower elevations transitioning to
snow for the latter half of the night. Min temperatures will
randing from the mid 20s to low 30s.
As surface low pushes eastward toward the Canadian maritimes, a
ridge of high pressure builds across the lower Ohio valley,
putting the north country in NW flow. This will result in
precipitation becoming more orographic by Saturday morning.
FROUDE numbers of 0.5 to 1 indicate slow moving blocked flow on
Saturday, helping to focus snowfall on western slopes and in the
higher terrain. There`s a chance for brief disruption in flow
late in the day as 500mb vort swings across the North Country,
providing a slight chance to chance of mostly snow across the
forecast area. Max temperatures on Saturday will remain in the
Saturday night the surface ridge shifts eastward over the
eastern Great Lakes by Sunday morning. Moisture over the North
Country looks to diminish from top to bottom with lingering
clouds under inversion. Expect snow showers to end by daybreak.
Forecast snowfall totals throughout the short term are a dusting
to quarter inch in the broad valleys, with few tenths of an
inch to 3 inches in the higher elevations. Min temperatures
generally in the 20s.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 311 PM EST Thursday...High pressure is the dominant
feature Sunday and Sunday night, resulting in a brief period of
dry weather. Remaining under light northerly flow, temperatures
remain cooler Sunday with maxes in the 20s to mid 30s. Min
temperatures will range from the mid teens to mid 20s Sunday
Another mid level trough arrives Monday morning, weakening as
it moves across the region and resulting in only chance POPs as
ridging returns Monday night. With max temperatures in the 30s,
generally expect light snow showers.
A more significant system takes form Tuesday, bringing in
precipitation from the south and west. Still much disagreement
among models, but as initial precip looks to be the result of
warm air advection/warm front, there`s a chance for mixed
precipitation Tuesday night into Wednesday. GFS shows southern
stream low develop into closed coastal low moving near the 70/40
benchmark as another surface low associated with very large
500mb trough approaches the region from the west. 12Z ECMWF not
available at time of forecast for comparison.
.AVIATION /00Z Friday THROUGH Tuesday/...
-- Changed Discussion --Through 00Z Saturday...Mainly mostly cloudy skies expected
through the period as the region remains under cyclonic flow
from a closed upper low over Quebec. Expecting VFR with areas of
MVFR ceilings at KSLK/KMSS along with scattered rain and snow
showers expected through the period before all locations trend
down to MFVR during the day on Friday. Snow showers will be
mainly over the higher elevations of the Adirondacks and Green
Mountains. West-southwest surface winds will gust from 15-25
knots through the period.
Outlook 00Z Saturday through Tuesday...
00Z Saturday through 18Z Sunday...Mix of VFR/MVFR with local
IFR at KSLK in scattered rain/snow showers.
18Z Sunday through Monday...Mainly VFR with high pressure
building in. Periods of MVFR ceilings possible.
-- End Changed Discussion --