Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
1006 PM EST Thursday Nov 26 2015
mild temperatures and breezy conditions continue tonight with
increasing clouds ahead of a cold front that will advance through
the region Friday afternoon resulting in rain showers through
Friday night. Behind the front, dry and seasonable weather will
persist over the weekend into early next week. Another system will
affect the region with rain on Tuesday.
Near term /until 11 am Friday morning/...
as of 1001 PM EST Thursday...a breezy and mild night underway in
the Champlain/St. Lawrence valleys as strong pressure gradient
remains in place between anticyclone east of Nova Scotia and the
slow moving frontal system across the central Great Lakes into
central Ontario. Some valley locations east of the Green Mountains have
decoupled with a shallow inversion allowing temperatures to fall into the
32-34f range. Meanwhile...temperatures have been steady around 50f in the
Champlain and St. Lawrence River valleys where conditions remain
well-mixed. The normal low is 27f at btv...and will see morning
lows hovering near 50f as S-SW winds of 15-20 miles per hour...with gusts to
35 miles per hour continue. Surface cold front remains well upstream across the
central Great Lakes region...with just scattered high clouds in
place for the overnight hours. No shower activity is expected
Models in fair agreement with precipitation associated with the
front will hold off until late Friday morning/early afternoon.
Expect frontal rain showers to move from northwest to se, reaching the
St. Lawrence Valley around 18z Friday...and then the Champlain
Valley and northern Vermont in the middle-late afternoon...and the
remainder of Vermont toward early evening Friday.
925mb temperatures will range from 7-9c resulting in surface maximum
temperatures well into the 50s for most sections of the north
country on Friday...and locally near 60f in the Champlain Valley.
Short term /11 am Friday morning through Saturday night/...
as of 315 PM EST Thursday...cold front will move southeastward
across the region early Friday night...with precipitation changing over
to snow late Friday night before ending early Saturday morning.
Best chance for any accumulating snows will be above 1500 feet
with generally a trace or less elsewhere. Strong cold air
advection with surface high ridging into the north country for
Saturday and Saturday night following departing cold front. Friday
night through Saturday night will feature cool
temperatures...Saturday night will be the coldest with some teens
in the coldest spots of the Northeast Kingdom and Adirondacks.
Highs on Saturday will be in the middle 30s to middle 40s.
Long term /Sunday through Thursday/...
as of 315 PM EST Thursday...large surface and upper level ridge will build over the
region from Sunday through early Tuesday. Quiet weather is expected
during that time period. Next system to impact the north country
will approach Tuesday from the western Great Lakes...and slowly lift
northeastward through Wednesday night. Mainly rain expected with
this system with possibly just a quick change over to snow at the
end as colder air works into the area.
Aviation /03z Friday through Tuesday/...
through 18z Friday...some low level wind shear possible overnight at slk and mpv
with strong southwesterly gradient flow in place...including SW winds 40-50
kts around 2kft above ground level. Otherwise...VFR and breezy at all sites through
16z Friday. S-SW winds generally 10-20 kts with gusts to 30kts
possible at btv with good low-level mixing and channeled flow in
the Champlain Valley. Cold front approaches from southeastern Ontario
during Friday afternoon. Expect vcsh and conditions lowering to
borderline VFR/MVFR ceilings around 18z for kmss and kslk...and
developing rain showers with the approaching cold front at all
terminals during Friday afternoon. Conditions will deteriorate to
MVFR areawide with localized IFR possible at slk/mss after 21z
Friday due to expected low ceilings with cold frontal passage.
Outlook 00z Saturday through Tuesday...
18z Friday through 18z Saturday...trending to MVFR in rain
showers as a cold front drops south into the region from Canada.
Some MVFR/IFR in snow showers possible 00z-12z Saturday as
18z Saturday through 18z Tuesday...VFR under high pressure.
18z Tuesday Onward...VFR conditions deteriorating to MVFR/IFR as
low pressure system bring rain to the north country.
as of 1 PM EST Thursday... a lake Wind Advisory remains in effect
Modestly strong and gusty south winds of 20 to 30 knots are
expected on the lake today and will likely continue into tonight
before slowly abating on Friday. The highest winds to generally
occur across the central and northern portions of the lake where
significant wave heights will range in the 2 to 4 foot range with
a moderate chop. Bays and inlets with open southerly exposure will
also see waves on the higher end of the forecast range. These
conditions will pose a hazard to small craft operating on the lake
over the next 24 hours.