FXUS61 KBTV 100816
Area Forecast Discussion
National Weather Service Burlington VT
316 AM EST Sun Dec 10 2017
The North Country will be in between systems tonight with an
upper trough to our west and coastal low pressure to our east.
Later this afternoon and tonight, snowfall associated with the
coastal low will work into eastern portions of the forecast
area, with some light accumulations expected through the night.
Late tonight into Sunday the trough to our west will bring some
scattered snow showers to the region before a more widespread
light snow event is expected Monday night into Wednesday morning
as a low pressure system moves down from Canada.
.NEAR TERM /THROUGH MONDAY/...
As of 1250 AM EST Sunday...Still getting light snow across all
but northwest Vermont early this morning. Reduced visibilities
exist across southern and eastern Vermont and will continue the
winter weather advisory for Rutland...Windsor... and Orange
counties through 300 am. Precipitation should decrease in
intensity and areal coverage after 300 am to allow for the
advisory to come to an end. At the same time upstream trough
will be moving east toward northern New York and should see
precipitation chances slowly begin to increase.
For Sunday, coastal low pressure exits east of the region while
a digging upper trough over the Ohio Valley tonight lifts
northeastward into the New England states. A brisk westerly flow
develops by mid-day with winds in the 10-15mph range and gusts
up to 20 mph, especially across portions of northern New York.
Southwesterly flow combined with some weak elevated instability
will once again produce periods of lake effect snow showers in
the lee of Lake Ontario through the day, mainly affecting the
Adirondacks, but a modest 850mb jet of 25-35kts should be enough
to transport some activity into portions of northern Vermont,
especially in the northern mountains around Jay Peak. Through
Sunday night expect to see a solid 1-3" across southern St.
Lawrence and Franklin counties as well as western portions of
Clinton and Essex counties in New York. Could see localized
amounts of 3-5" in the vicinity of Star Lake and Wanakena.
Eastward across the northern Greens a general dusting to 2" is
expected, with localized amounts up to 4" near Jay Peak. Near
normal temps are forecast for Sunday and Sunday night with highs
in the upper 20s to mid 30s, and lows in the teens.
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
As of 315 AM EST Sunday...By Monday night into Tuesday a well-
advertised northern stream clipper low will take a favorable
track toward and atop the area with a widespread light snow
event expected. Some surface low re- development of Miller
Type-B character does occur to our east in the Gulf of Maine
through the day on Tuesday. However the majority of the synoptic
forcing for snow in our area will come in two phases, the first
occuring during this period from broad warm advective processes
and upward lift in the mid-levels as the parent low nears. At
this point it appears the primary window for steadier snowfall
will occur from the pre-dawn hours through late-afternoon on
Tuesday before best synoptic lift pushes to our north and east.
Blended 24- 30 hour QPF output, with some downward adjustment
owing to typical warm-advective model bias suggests totals in
the 0.15 to 0.35 range with slight enhancement possible along
eastern slopes of the Greens/Dacks. Time-averaged snow ratios in
the 15-20:1 range support totals generally ranging from 3-6
inches with local variation which suggests a potential advisory-
level event for favored areas. Time will tell. Temperatures
should be on the seasonably cool side with lows mainly in the
teens and highs on Tuesday from the mid 20s to lower 30s. Winds
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 315 AM EST Sunday...Phase two of our pronlonged light
snow event then evolves over time by Tuesday night and
especially into Wednesday as secondary low pressure deepens
significantly while tracking into the Maritimes. The parent
700-500mb closed low tracks atop our area during this period
with deeper moisture returning on evolving gusty northwest flow
as pressure gradient tightens significantly. Areal coverage of
light snows/flurries will have initially tapered off during the
first half of Tuesday night, but as aforementioned features
pivot into the area a general re-blossoming of light snows/snow
showers should occur as we progress into the daylight hours on
Wednesday. The best coverage should occur across favored
northern higher terrain and accompanying western slopes where
orographic enhancement will become increasingly favored.
Additional light accumlations in these areas look likely at this
point which will be welcome for resort areas gearing up for the
Christmas Holiday. Temperatures will trend colder during this
period with lows Tuesday night in the upper single digits to mid
teens and corresponding highs on Wednesday holding nearly
steady in the teens with the brisk flow creating somewhat
uncomfortable wind chills in the single digits.
Thereafter global models suggest the overall large-scale pattern
remains generally unchanged with a western CONUS synoptic ridge and
a corresponding downstream eastern U.S. trough. Weak ripples of
energy moving through the background cyclonic flow aloft will create
near daily chances of snow snowers or flurries, with higher chances
during Friday and possibly again by later next weekend. At least
that`s the broad consensus at this point. Temperatures will remain
on the chilly side during Thursday (teens for highs), though begin a
slow moderation process from Friday onward as core of CP airmass
lifts gradually northward.
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
Through 06Z Monday...Light snow continues at KRUT and KMPV with
MVFR/IFR conditions expected through about 10z before conditions
improve into the VFR category as the light snow moves east of
the area. Over the remainder of the area VFR conditions will
exist...but after 12z a trough of low pressure will move into
the region and produce MVFR/VFR ceilings and visibilities as
scattered to numerous snow showers move from west to east across
the region. Watch for a wind shift around midday to the west
with the passage of a cold front.
Sunday Night: VFR. Chance SHSN.
Monday: Mainly VFR, with local MVFR possible. NO SIG WX.
Monday Night: Mainly VFR, with local MVFR possible. Likely SN.
Tuesday: Mainly MVFR, with areas IFR possible. Likely SN.
Tuesday Night: Mainly MVFR, with areas IFR possible. Chance SHSN,
Wednesday: Mainly MVFR, with local IFR possible. Chance SHSN.
Wednesday Night: Mainly MVFR, with local VFR possible. Chance
Thursday: Mainly VFR, with local MVFR possible. NO SIG WX.