Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
647 am EST sun Dec 28 2014
a cold front will move across the area this morning, bringing
gusty winds and light rain showers for the first half of the day.
Drier and colder air will filter in behind the cold front,
starting a colder trend for the work week. A reinforcing shot of
colder air will follow a weak surface trough on Monday, resulting
in maximum temperatures staying in the teens and 20s this week.
Near term /until 7 PM this evening/...
as of 647 am EST Sunday...back edge of precipitation shield has
moved through the Saint Lawrence valley, ending rain showers
there. Expect the back edge to continue to swiftly move across the
Adirondacks and Champlain Valley before 14z, and exit southeastern
Vermont shortly after 15z. Radar VAD wind profiles show winds
decreasing, so expect gusts to diminish in the middle morning hours.
Mild temperatures, gusty winds and light rain showers across the
north country this morning as a result of being in the warm sector
of a surface low pressure system that is traversing northeastward
across Quebec. The associated cold front with this system is
currently moving across the western St Lawrence Valley as of
1140z. Expect the front to cause south to southwesterly winds to
shift to the west across the area by mid-day. Cooler air will
filter in behind the front...causing temperatures to generally
fall throughout the day. Therefore the maximum temperature will occur
in the morning, with temperatures dropping to the m20s-m30s around
5pm. Low level clouds remain behind the front, with not much
chance for full sunshine today, though some breaks/clearing are
expected in the afternoon to evening hours.
Gusty winds will also subside behind the front, as winds shift
from south to west and low level jet exits eastward in the late
Short term /7 PM this evening through 6 PM Monday/...
as of 343 am EST Sunday...behind the front, drying west to
northwest flow continues, allowing for dissipating clouds. Low
temperatures Sunday night/Monday morning will fall into the teens
and middle 20s.
On Monday, a weak surface trough will move through the north
country from north-northwest to SSE, increasing cloud cover and possibly
producing a few snow showers mainly across the higher terrain on
northwest facing slopes. Models show weakening deformation as the
trough moves over the north country, and washing out late Monday
afternoon. Do not expect much accumulation with this feature.
However, there will be a reinforcing shot of colder air behind it,
with persistent north to northwest flow. Monday maximum temperatures
will range from the teens to low 30s, while Monday night will be
noticeably colder in the negative single digits at the summits to
low teens in the valleys of south central Vermont.
Long term /Monday night through Saturday/...
as of 343 am EST Sunday...cold air advection develops Monday
night as a large area of high pressure spreads into the region
from the west and northwest. This will result in colder and drier
conditions with lows Monday night getting down into the single
digits above and below zero. The below normal temperatures
continue on Tuesday with highs in the middle teens to middle 20s...which
is generally 10 to 15 degrees below normal. Dry weather will
continue on Tuesday. Little change is expected on Wednesday with
below normal temperatures continuing and maybe a little bit of
lake effect snow across parts of northern New York. Otherwise...a
pattern change will take place on Thursday as an upper level
trough of low pressure moves into eastern Canada and brings a
chance of snow showers to much of the area through Thursday night.
An even more noticeable change comes late Friday into Saturday as
southwest flow aloft develops and brings warmer air into the
region. In addition...a large upper level trough of low pressure
will approach the region on Saturday. Ultimately a surface low
pressure system will track to our northwest which puts US in the
warm sector. Based on this scenario...looking like snow at the
start of the event and then change to rain or a rain/snow mix most
Aviation /12z Sunday through Thursday/...
through 12z Monday...cold front moving through the St Lawrence
Valley as of 1140z...with wind gusts subsiding in its wake and
some breaks in overcast. VAD wind profiles showing winds aloft
diminishing, so occurrence of low level wind shear and surface gusts decreasing.
Rain showers ahead of cold front providing some MVFR ceilings especially in
the higher terrain...kslk/kmpv/krut. After the front passes this
morning, exiting south eastern Vermont after 15z, winds will shift
from south to west and remain around 8-15kts. Also ceilings should
increase to VFR by the early afternoon, except at kslk.
Heading into the evening hours, northwest winds at 5-10kts
prevail with VFR conditions and a brief break in overcast. An increase
of low level moisture expected towards dawn Monday morning, ahead
of a weak surface trough approaching from the north.
Outlook 12z Monday through Thursday...
12z Monday Onward...mainly VFR through the period. Exception at
kslk where westerly flow will allow scattered -shsn and occasional
MVFR/IFR conditions to prevail.
as of 340 am EST Sunday...a lake Wind Advisory remains in effect
this morning as south winds continue at 15 to 25 knots, resulting
in waves heights of 1 to 3 feet...with some higher swells
possible. A surface cold front is approaching Lake Champlain from
the west, keeping the pressure gradient tight along with
channeling up the valley producing winds around 25 knots between
09z and 15z. When the front passes over the lake this morning,
winds will shift to the west/northwest and slowly weaken as high
pressure builds into the region.