FXUS61 KBTV 090558
Area Forecast Discussion
National Weather Service Burlington VT
1258 AM EST Sat Dec 9 2017
Variably cloudy skies will persist across the North Country
tonight, between an area of low pressure across the central
Great Lakes and a developing low off the coast of the Carolinas.
Conditions will generally be dry tonight and Saturday morning,
with just a few mountain or lake effect flurries possible,
mainly across northern New York. The coastal low will track
southeast of New England late Saturday into Saturday night,
bringing light snow to central and eastern Vermont, especially
during the first half of Saturday night. Light accumulations of
one to three inches are possible across eastern portions of
Vermont. Thereafter, an Alberta clipper will bring additional
chances for light to moderate snowfall late Monday night into
Tuesday. Temperatures will generally trend colder next week,
especially in the wake of the clipper system during the mid to
later portion of the work week.
.NEAR TERM /THROUGH TONIGHT/...
As of 1258 AM EST Saturday...Overall forecast in good shape
with just some minor tweaks to match current conditions. Any
chance for precipitation will be out in the Saint Lawrence
Valley where some lake effect clouds/snow persist.
Narrow ridge of high pressure in place over PA/NY will bring
relatively quiet weather conditions tonight into Saturday
morning. The 700mb shortwave trough in the central Great Lakes
has backed the low-level flow enough that lake effect snow has
largely dissipated off Lake Ontario. Will still be dealing with
lake effect clouds advecting across our region, especially into
the Adirondacks and St. Lawrence Valley, with just a few upslope
flurries possible in the nrn mtns. With the variably cloudy
conditions expected, decided to go a few degrees above the MOS
consensus tonight, with limited radiational cooling. Overnight
lows generally expected in the low-mid 20s, except some upper
teens east of the Green Mtns and in the Adirondacks if
sufficient breaks can develop later tonight. P-gradient weakens
during the overnight. The prevailing S-SW winds 5-10 mph this
afternoon will generally become light and variable after sunset.
On Saturday, wave low off the North Carolina coast will track
northeastward to near/just SE of the 40N 70W benchmark at 00Z
Sunday, and toward southern Nova Scotia by 06-09Z Sunday. Will
see an increase in mid-upr level clouds thru the day Saturday,
with high temperatures in the low-mid 30s. Based on 12z NWP
guidance suite, it continues to appear that central/Eastern VT
will get into the wrn fringe of the precipitation shield
associated with synoptic forcing late Saturday afternoon into
Saturday night. Highest PoPs generally 00-06Z Sunday, ranging
from 70% in the CT River Valley, down to 40% or so in the
Champlain Valley. Looking for a light snow accumulation of
1-3"...with around 1" for MPV and generally 2-3" in the CT River
Valley. Not anticipating any major travel issues, but some
slowdowns due to snow covered roads can be expected Saturday
evening/night east of the Green Mtns, including along I-89/I-91.
Mid-level trough shifting ewd from NY/PA may bring a few
additional snow showers to the region later Saturday night, and
have indicated a more widespread 20-30 PoP across the region
during the pre-dawn hrs Sunday. Again, prevailing overcast
should preclude much radiative cooling with lows mostly in the
low-mid 20s for Sunday morning.
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
As of 351 PM EST Friday...Shortwave and deep upper trof axis
moving across area thus winds should be more WNW to keep any
lake effect snow activity to our south. There are some subtle
differences in positioning of surface trof across Lake
ontario...close enough to my adirondack zones to have slightly
higher pops to blend with WFO BUF better but main event should
be to our south. Otherwise, there will be some mountain snow
showers due to the instability of the colder air with
temperatures around freezing.
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 351 PM EST Friday...It`s beginning to look alot like
winter...actually continuing the trend that has finally become
established. HUGE, deep trof carved out across eastern NOAM will
largely stay in lace across our region with several shortwaves
re-energizing the trof bringing replenishing cold air and
clippers with chances of accumulating snow.
Monday we are between systems thus some minor short wave ridging and
mainly dry with colder temperatures in the 20s across the north
Monday night-Tuesday-Tuesday night...Next deep/strong shortwave
drops down across Northern Plains/Great Lakes and eventually
rotating across the Northeast on Tuesday. Surface clipper moving
through with widespread light snow developing Monday night into
Tuesday becoming more snow showery Tues aftn/eve. Models have been
back/forth on the shifting of energy and the development of a
coastal low...Gulf of Maine or south/near Cape. Latest trend,
including ECMWF is Gulf of Maine but still enough
energy/moisture for a moderate clipper snowfall...possibly
advisory level (3-5+").
Wednesday...cold air has been replenished by above clipper. Mainly
dry with still some leftover mountain snow shower possible and Highs
only in the teens-L20s.
Thursday is similar to Monday...between systems and slight ridging
ahead of next shortwave. Mainly dry with temps similar or warmer by
a few degrees from Wed.
Thursday night-Friday...another clipper, not as strong and more
moisture starved then Tuesday`s event yet still some light snow/snow
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Through 06Z Sunday...Overall looking at VFR conditions through
much of the period. Area will be in between systems with an
upper level trough remaining to our west and deeper moisture
off the Eastern Seaboard. However...the moisture to our east
will work its way westward this afternoon and tonight and light
snow should work into eastern Vermont and KMPV will have the
potential to experience MVFR ceilings/visibilities with all
other aviation sites remaining in the VFR category.
Sunday: Mainly VFR, with local MVFR possible. Chance SHSN.
Sunday Night: Mainly VFR, with areas MVFR possible. Chance SHSN.
Monday: Mainly VFR, with areas MVFR possible. Slight chance SHSN.
Monday Night: Mainly MVFR, with areas of IFR possible. Chance SN.
Tuesday: Mainly MVFR, with areas of IFR possible. SN likely.
Tuesday Night: Mainly MVFR, with areas of IFR possible. Chance SN.
Wednesday: VFR/MVFR. Chance SHSN.