Scientific Forecaster Discussion
fxus61 kbtv 200921
Area forecast discussion
National Weather Service Burlington Vermont
421 am EST Sat Jan 20 2018
a weak warm front is lifting across the region currently
bringing with it above freezing temperatures and breezy
southwest winds. Localized wind gusts to 30 mph are expected
over the Saint Lawrence and Champlain valleys as well as across
the international border across New York. This front shift back
south as a cold front with additional clouds and cooler
temperatures later Saturday evening. A few mountains snow
showers with a light accumulation is possible. Late Monday into
Tuesday brings the next significant chance of precipitation in
the form of a wintry mix. While not as pronounced as last week's
system, with ice jams in place close monitoring will be needed
for the early part of next week.
Near term /through Sunday/...
as of 420 am EST Saturday...weak warm front sits across the
international border and should continue to remain there before
waving back south later on tonight. Hi-res models continue to
show strong southwest low level jet of 50-65 knots at 850mb.
This will bring gusty winds initially across the St Lawrence
Valley across the early morning hours with localized gusts of 30
to 35 mph eventually shifting over northern New York near the
international border and the Champlain Valley and parts of
southern VT later this morning before jet shifts east out of the
County Warning Area. Models also still show a rather complex thermal profile
across the region. Warm air is moving into the St Lawrence and
Champlain valleys a bit of a faster pace than expected, so even
with bumping high temperatures up a bit from the previous
forecast, some locations could still see a bit higher,
especially is cloud cover decreases temporarily across some of
the valley locations this afternoon. A few flurries are possible
over the dacks and northern greens this afternoon, but overall
moisture is minimal at best, so accumulation will be very light.
Look for high temps to be in the upper 30s to lower 40s with a
few locations pushing mid 40s.
Saturday night will be rather quiet and mild as the weak cold
front starts to wave back south. Overnight lows will be in the
20s with some locations near the international border seeing
temps in the teens. Sunday continues the quiet weather with
cooler but still above seasonal normal temps with increasing
cloud cover ahead of the next system and a chance for a shower
or two in the higher elevations. Look for highs in the lower to
Short term /Sunday night through Monday/...
as of 420 am EST Saturday...westerly flow aloft will prevail
Sunday night into most of Monday. Perhaps there will be a
little bit of light snow up along the Canadian border Sunday
night...but most of the area will remain dry. Large high over
eastern Canada will allow for some colder air to move into parts
of the region on Monday...especially near the Canadian border.
Highs on Monday will generally be in the 30s...with upper 20s
near the Canadian border. Warm front will move into the region
from the southwest late in the day on Monday and bring some rain
or snow to parts of the area...with a little light mixed
precipitation across parts of northern New York.
Long term /Monday night through Friday/...
as of 420 am EST Saturday...best potential for mixed
precipitation/icing will occur Monday night into Tuesday. At
this time thermal profile supports the idea of mixed
precipitation for northern New York with mainly snow over
Vermont through the first of the night before low level warming
takes over across northern New York and most of Vermont. The
Northeast Kingdom of Vermont will be the last to changeover and
thus some icing may also be concentrated in this area. This area
and the Saint Lawrence valley/western portions of the northern
Adirondacks should see at least a tenth of an inch of ice. Would
not be surprised for a number of areas in Vermont to pick up an
inch of two of snow before a change to mixed precipitation
and/or rain. Most areas will ultimately see rain on Tuesday with
highs in the upper 30s to lower 40s. Precipitation
probabilities Monday night and Tuesday should essentially be
categorical...but there may be a brief break in the
precipitation late Monday night as area gets in the warm sector.
Shortwave trough and cold front exit the region Tuesday
night...but we still stay in the main upper trough. Colder air
moves in so precipitation will essentially be snow showers
Tuesday night into Wednesday as highs will only be in the 20s to
lower 30s. Looks like we trend toward a northwest flow aloft
pattern for Thursday and Friday. Should be relatively dry...but
below normal temperatures are expected.
Aviation /10z Saturday through Wednesday/...
through 00z Sunday...generally expect VFR conditions through the
overnight hours along with some scattered flurries. Not
expecting the flurries to accumulate or have any impact on
flight conditions. Low level jet of 45 to 60 knots develops
overnight into early Saturday morning...with localized gusts
btwn 25 and 30 knots likely at slk/mss and btv. Elsewhere...low
level wind shear with areas of moderate turbulence can be
anticipated overnight into Saturday morning. Mainly VFR
conditions Saturday will trend toward MVFR and eventually IFR
cigs after 00z Sunday.
Sunday: mainly VFR, with local MVFR possible. Slight chance shsn.
Sunday night: mainly MVFR, with areas VFR possible. Slight chance
Monday: mainly MVFR, with local VFR possible. Chance sn, chance
Monday night: mainly MVFR, with local IFR possible. Likely sn,
likely pl, definite ra, definite freezing rain.
Tuesday: mainly MVFR, with areas IFR possible. Definite ra,
definite freezing rain.
Tuesday night: mainly MVFR, with local IFR possible. Chance shsn,
chance fzra, chance pl.
Wednesday: mainly MVFR, with areas VFR possible. Chance shsn.