FXUS61 KBTV 240514
Area Forecast Discussion
National Weather Service Burlington VT
1214 AM EST Fri Jan 24 2020
Above normal temperature are expected across the North Country
through Friday as high pressure remains anchored across the
Northeast US. A system is poised to impact the region late
Saturday into Sunday. Snow will transition to a mix of sleet or
freezing rain Saturday night, mainly over portions of the
Adirondacks of New York and along and east of the Green
Mountains of Vermont. Most of the lower elevations will see snow
transition towards rain. On Sunday, a transition of rain or
snow is expected becoming more snow over the afternoon. Towards
midweek, quiet and above normal conditions resume for the next
.NEAR TERM /THROUGH SATURDAY/...
As of 1209 AM EST Friday...No real changes needed with this
update. Temps continue to remain steady or are slowly falling
across the area as of the bottom of the hour under mostly cloudy
skies. Current forecast has this handled well.
Previous Discussion...South winds are gradually winding down
with calm or light and variable winds expected tonight. We continue
with filtered sun. These thin high clouds are expected to prevail
and can be seen throughout much of the eastern US. Simulated IR
forecasts do want to hint at a break in high cloud around sunrise.
Overall, expect forecast temperatures to play out a bit similar to
last night. We are currently in the upper 20s to upper 30s, and
temps will slowly fall down overnight. As we get into that potential
break near sunrise, we could see a faster rate of cooling. Southerly
flow aloft will remain and we will have 1-2 C 850mb temperatures, so
should see a spread where the mountains are warmer than lower
elevations. Low temps will be tricky with quite a bit of local
On Friday, high pressure begins to retreat eastwards. Additional
pockets of high clouds are expected. Highs should creep into the mid
30s to lower 40s. We should see some recycled marine airmass move in
over eastern Vermont late Friday night. There could be some pockets
of drizzle in this area, but for now, have shown much higher cloud
cover over eastern Vermont using forecast RH below 900mb and
blending with NBM, which shows the potential well. With this and
continued periods of mid to high level clouds passing overhead, the
low temperature forecast Friday night will be tricky, especially as
south winds again pick up ahead of the next system. Expect mostly
20s, but parts of eastern VT could be in the teens. Precipitation
will begin approaching from the south.
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
As of 337 PM EST Thursday...A low pressure system will bring a mixed
bag of wintry precip to the North Country Saturday into Sunday.
Conditions aloft such as a negatively tilted trough, positive
vorticity advection, divergence, and ample moisture favor a
widespread precipitation event; however, the challenge remains
regarding the type of precip. An occluded surface low will approach
from the west Saturday afternoon before a secondary surface low
develops along the Mid-Atlantic coast Saturday evening. This will
induce easterly/southeasterly flow into the area, causing
moisture/low clouds to be trapped along the east side of the Green
Mtns Saturday morning, keeping mild low temperatures in the mid 20s.
Winds will likely become gusty Saturday afternoon and evening
(25-35kts), especially along the western slopes of the Green Mtns
and Adirondacks with a southeasterly low level jet of ~50kts. High
temps for Saturday will be in the upper 20s across higher terrain,
near freezing across eastern VT, and mid 30`s within the valleys.
Precipitation will begin Saturday afternoon, though there remains
some disagreement in the models regarding timing. At the onset,
precip will begin as snow across higher terrain, with a rain/snow
mix within the valleys. Surface temps will warm through the
afternoon and evening under warm air advection and southerly flow,
allowing for a mix of precip across the area. Though accumulating
ice is more likely along higher terrain and eastern VT where
temperatures will remain cooler. Mixed precip will continue
overnight, becoming snow on Sunday as temps aloft cool. During this
time, winds become more westerly, ushering in a regime of mild cold
air advection on the back side of the departing surface low. Sunday
morning lows will be a bit warmer (near freezing) with highs only a
few degrees warmer in the mid 30s.
Overall, storm total QPF will be half to 3/4 of an inch, with lesser
amounts (~0.25") within the Champlain Valley and the Northeast
Kingdom due to SE shadowing. Snows totals expected of 1-3" across
the area, with little to no accumulation in the Champlain Valley.
And total ice accumulations are expected of 0.10-0.25", though
confined to higher terrain of the Dacks/Greens and parts of eastern
VT, including NEK.
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 337 PM EST Thursday...The deep and closed mid/upper lvl
cyclonic circulation wl be slowly moving acrs southern Canada Sunday
Night/Monday with favorable upslope winds and moisture. Have
continued to mention likely pops Sunday Night into early Monday for
a continued period of accumulating snowfall in the mtns. Thermal
profiles are relatively warm given northwest 925mb to 850mb winds of
30 to 40 knots, supporting denser type snow ratio`s. Progged 925mb
temps in the -2c to -4c, while 850mb values are -4c to -6c, support
lows mainly in the 20s to lower 30s overnight, with gradually
cooling profiles for Monday into Tues. Also, noted in the sounding
data, moisture thinning in the favorable snow growth zone, as
upslope winds prevail on Sunday Night/Monday, which may result in
area of drizzle/freezing drizzle. Confidence in depth of moisture
and relation to DGZ is still uncertain at this time, so have mention
just snow or rain showers based on sfc temps. Highs on Monday
ranging from upper 20s to mid 30s with lingering mountain snow
For midweek, 1026mb high pres near Hudson Bay noses into our cwa,
while mid/upper level heights increase with building ridge aloft.
This general synoptic scale setup will feature mainly dry and quiet
period of weather, with the potential for large localized temp
differences, especially at night. Coolest values in the
deeper/protected valleys with warmest in midslopes and CPV areas.
Highs generally mid 20s to lower 30s for Tues thru Thurs, with lows
generally 5 to 15, but some cooler values possible.
.AVIATION /05Z FRIDAY THROUGH TUESDAY/...
Through 06Z Saturday...VFR conditions will continue through the
TAF period with light and variable winds persisting through
Friday morning. Winds will begin to turn from the southeast
across the area after 20Z with winds in the 8 to 14 knot range
at KRUT & KMPV. Elsewhere, winds will likely remain below 5
knots throughout the forecast period.
Saturday: Mainly VFR, with local MVFR possible. Definite RA,
Chance SN, Definite FZRA.
Saturday Night: Mainly MVFR, with local IFR possible. Windy with
gusts to 30 kt. Definite RA, Definite SN, Definite PL, Definite
Sunday: Mainly MVFR, with areas IFR possible. Likely SHSN, Chance
Sunday Night: Mainly MVFR, with areas IFR possible. Chance SHSN.
Monday: Mainly MVFR, with areas IFR possible. Chance SHSN.
Monday Night: Mainly MVFR, with areas IFR possible. NO SIG WX.
Tuesday: Mainly MVFR, with local IFR possible. NO SIG WX.