FXUS61 KBTV 202048
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
348 PM EST Wed Feb 20 2019
Snowfall will develop during the evening hours tonight as a warm
front lifts through the region. Snowfall amounts of 3 to 5 inches
will be common across the Green Mountains and eastern Vermont while
the rest of the area will generally see 1 to 3 inches of snow.
Temperatures will warm through the overnight period which may allow
for some sleet to mix in with the snow across southern vermont and
portions of northern New York. After highs warm into the upper 30s
to mid 40s on Thursday, temperatures will return back to normal
values for Friday and Saturday before another, and more potent,
warm front lifts northward and raises temps into the mid to upper
40s for Sunday. Ahead of this front, a a mix of snow, freezing rain
and sleet will be seen as temperatures are slower to cool at the
surface compared to just off the surface.
.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 348 PM EST Wednesday...A low pressure system located over
Virginia will continue to track northeastward heading into Thursday.
As this happens, a warm front will continue to lift northward toward
the North Country. Snowfall ahead of this warm front will move into
southern Vermont and portions of northern New York between 6 and 8
PM and into central and northern Vermont between 8 and 10 PM.
Snowfall amounts will be greatest across the eastern half of Vermont
(from the Green Mountains eastward) with greatest frontogenetic
forcing being closer to the low pressure system. Snowfall amounts
will range from 3 to 5 inches across eastern Vermont with the rest
of the forecast area seeing between 1 and 3 inches. As warmer air
begins to filter in aloft behind the warm front, there is the
possibility for some sleet to mix in with the snow. Warmer air aloft
will begin to partially melt and refreeze as it falls below the
melting later across southern Vermont and portions of northern New
York after midnight tonight. Based on the latest high-res guidance,
they are trending toward a "colder" solution which would minimize
the potential for mix but still looks favorable for some locations
to see some sleet mix in.
Temperatures for the large part will either be steady-state or
warming throughout the night with increasing warm air advection. In
addition, gusty southerly winds will develop toward morning which
will aid in mixing down warmer air. These gusty winds won`t be
particularly strong but will range between 20 and 35 mph. We get dry-
slotted pretty quick Thursday morning which will allow much of the
precipitation to end toward sunrise but a good westerly jet should
help showers linger on the western slopes of the Adirondack
Mountains as well as the northern Green Mountains. Thermal profiles
would support a mix of rain and snow which would lean towards more
rain during the late morning and afternoon hours and trend toward
mostly, if not all, snow as a cold front slides through late
Thursday. High temperatures on Thursday will range from the upper
30s to mid 40s with lows dropping into the 20s.
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 312 AM EST Wednesday...Overall looking at a fairly quiet end to
the work week with some higher elevation show showers Thursday night
on northwest upslope flow giving way to high pressure building into
the region for Friday and Friday night. Friday will feature a slow
trend towards clearing skies as the surface high approaches,
centering over the North Country Friday night. Temps will be
seasonably cool in the teens to low 20s for lows and low/mid 30s for
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 312 AM EST Wednesday...Best day of the weekend will be Saturday
as the aforementioned surface high pressure centers over the
Northeast while an upper ridge crests over the region as well. Skies
start the day mostly clear with just some increasing mid/high clouds
during the afternoon in advance of our next system. Temps will be
spring-like in the mid 30s to near 40.
Forecast remains on track going into Saturday night when our next
system arrives. Continue to see good model agreement in the overall
track and thermal profile of the system with only noise level
differences in timing and intensity. Primary low pressure developing
in the lee of the Rockies Saturday will track northeast through the
Great Lakes Sunday ushering a strong warm front through the region
early Sunday and a cold front Sunday night. Latest GFS/FV3/ECMWF
have trended warmer than yesterdays 00Z runs leading to an increased
threat of mixed precipitation with cold high pressure dammed in
place at the onset of the event. Forecast soundings indicate ptype
perhaps starts as snow late Saturday evening but rapidly changes to
a mix of snow/sleet/fzra after midnight into Sunday morning before
going over to all rain by the noon hour as surface temps rise into
the 40s area-wide. Best chance for accumulating frozen precip will
be outside the Champlain and southern St. Lawrence Valleys where
temps should stay above freezing to support a mainly rain event, but
elsewhere ice accumulations of up to a tenth of an inch looks
During the day Sunday as precip transitions to plain rain a
complicating factor in the QPF forecast will be a strengthening
low/mid level southwesterly jet of 40-60kts which will likely
produce some upslope/shadowing effects along with gusts in the 25-35
mph range going into Sunday night. While we continue to highlight
high PoPs of 75-85%, thinking QPF will be on the low side and
showers may become more scattered in nature than the forecast
indicates, especially if the strength and location of a mid-level
dry slot progged to stay south of the region shifts north. Cold
front moves in Sunday night as the primary surface low tracks into
southern Quebec and we should see good areal coverage of snow
showers develop overnight with some light accumulations likely.
Snow showers linger in the mountains Monday on moist northwest flow
with the deeper valleys generally dry before high pressure drys the
whole region out for Monday night into Tuesday.
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
Through 18z Thursday...VFR conditions will persist through the
remaining afternoon hours with wind gradually increasing to
around 10 knots from the south. Between 01Z and 03Z, snowfall
will begin to move into TAF sites with IFR visibilities and MVFR
ceilings expected with the falling snow. Snow will taper off
quickest across valley locations with higher elevations like
KSLK and KMPV likely holding onto precipitation a bit longer.
There will be some sleet mixing in with the snowfall over KSLK
after midnight but it looks like precipitation will taper off
prior to TAF sites seeing a transition to some light rain. Winds
will become gusty from the south/southwest Thursday morning with
winds gusting between 18 kt and 22 kt. Ceilings will trend back
toward VFR Thursday afternoon.
Thursday Night: VFR. Chance SHSN.
Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. Likely FZRA, Chance RA, Chance PL.
Sunday: Mainly MVFR, with local IFR possible. Definite SHRA,
Definite RA, Definite FZRA.
Sunday Night: MVFR and IFR. Likely SHSN, Likely SHRA.
Monday: VFR. Windy with gusts to 30 kt. Chance SHSN.
VT...Winter Weather Advisory from 8 PM this evening to 10 AM EST
Thursday for VTZ003-004-006>008-010-012-017>019.