Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
944 PM EST Friday Jan 30 2015
periods of snow will end tonight as low pressure moves away from
New England. Much colder temperatures and bitterly cold wind
chills will follow for tonight into Saturday. High pressure will
build in for the weekend with temperatures much below normal.
Low pressure will pass south of New England on Monday. Temperatures
of 10 to 15 degrees below normal will persist into the middle of
Near term /until 7 am Saturday morning/...
as of 935 PM EST Friday...have canceled the Snow Advisory for
central and northern Vermont. Wind chill warning and advisory
continues as previously issued.
Snow continues to wind down with drier air moving in to the
region. Snow will linger into late night in the upslope areas of
higher terrain. Infrared satellite showing clear skies in St. Lawrence
Valley and holes in the overcast to downwind east side of
Adirondacks. Surface temperatures and dewpoints falling as drier
air moves into the region with single digits in northern New York
and low teens in Vermont. With this update blended sky from ruc13
model which has a good handle on the clearing skies. Previous
guidance has been outpaced by cooling temperatures and interpolated
observed temperatures into latest lav guidance to lower the hourlies. Min
temperature forecast has trended downward a degree or two but very little
change. Wind forecast of 10 to 20 kts and temperature forecast still
support wind chill warning for northern Adirondacks and St.
Lawrence Valley...and advisory for Champlain Valley east. BUFKIT
shows potential for wind gusts around 25 kts in eastern Vermont in
the tighter pressure gradient and closer to the surface low. Less
new snow in that part of the state however would minimize blowing
snow threat overnight. Review of low light webcams in the state do
not reveal blowing snow problems.
North/south oriented 500 mb trough axis over the Champlain Valley
extending south to just off the middle Atlantic coast. Water vapor
satellite showing vorticity maximum associated with earlier clipper has
lifted north of the area, and subsidence behind it will help with
trying and ending snow showers overnight. Secondary surface low
has developed just off southern New England coast will track
northeastward towards Nova Scotia overnight. Arctic air advecting
into the region behind todays cold front passage, and min temperatures well
below zero across northern New York...but lows will be closer to
zero from Champlain Valley eastward. However if clearing moves
further east into Champlain Valley or on into Vermont temperatures could
tank further east as well.
Short term /7 am Saturday morning through Sunday night/...
as of 335 PM EST Friday...wind chill warnings/advisories in
effect through midday Saturday.
Cold air advection continues Saturday morning with rather tight
pressure gradient between departing low and high pressure building
east from the Great Lakes region. 925 mb temperatures in the negative
teens to -20s and winds of 10-15 miles per hour with some higher gusts
continue. Maximum temperatures Saturday only in the single digits north and
lower teens south with wind chills 15 to 30 below through the
morning. Some morning clouds across northern Vermont...otherwise
plenty of sunshine courtesy of high pressure...with winds
subsiding in the afternoon.
As the surface ridge shrinks southward Saturday night...upper
wave and another cold front will bring clouds back into the region
along with the chance of snow showers...especially northern areas.
Temperatures will moderate a bit with lows ranging from negative
middle teens in the Northeast Kingdom to single numbers above zero in
southern Vermont. Return to northerly flow and cold advection
will keep temperatures from rising much on Sunday. Expect highs in
the single numbers north and teens south. Clouds return Sunday
night ahead of low pressure moving into the lower Ohio Valley.
Have introduced a chance of snow to southern areas...but better
chances for snow will lie further to the south. Min temperatures will be
well below zero across most of the area.
Long term /Monday through Friday/...
as of 300 PM EST Friday...extended forecast will continue to
feature active weather and colder than normal temperatures. Low
pressure system passing to our south on Monday brings a chance for
some light snow to southern Vermont. Surface high will then ridge
into the area for Tuesday and Wednesday. On Thursday another
weaker low pressure system will pass to our north bringing another
chance for light snow showers to northern New York and Vermont. By
Friday morning another large ridge of high pressure will be
building into the eastern Continental U.S.. Wednesday will be the only day of
the extended portion of the forecast with a chance at normal
temperatures...the rest of the period will be cold.
Aviation /03z Saturday through Wednesday/...
through 00z Sunday...lingering MVFR to intervals of IFR
visibility in light snow to be primarily confined to btv and mpv
given persistent blocked flow. For the btv taf however, the most
persistent light snows should become more tied to the western
slopes within the next 1-2 hours. Strong Canadian ridge of high
pressure then builds in from the northwest into the rest of the
overnight. Cold advection and drying aloft will allow for a rather
rapid clearing of overcast VFR/MVFR ceilings toward VFR all terminals
by morning. Though sustained winds will continue around 10-12 kts,
cold advection aloft will also allow for north to northwest gusts
to develop, particularly into the day Saturday (as high as 25
Outlook 00z Sunday through Wednesday...
00z Sunday-12z Monday...VFR.
12z Monday-00z Tuesday...mainly VFR as system slides south of
region. Could see some light snow across southern Vermont from 12z
Monday through 00z Tuesday as low pressure area passes south of
00z Tuesday-12z Wednesday...VFR.
12z Wednesday-12z Thursday...some MVFR in snow showers with
clipper crossing the area.
Vermont...Wind Chill Advisory until 1 PM EST Saturday for vtz001>012-
New York...wind chill warning until 1 PM EST Saturday for nyz026-027-
Wind Chill Advisory until 1 PM EST Saturday for nyz028-035.