Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
1010 am EDT Fri Oct 28 2016
developing coastal low pressure over southern New England will
produce occasional rain and snow across most of Vermont today with
scattered precipitation over northern New York. Additional wet snow
accumulation of an inch or so is possible below 2000 feet. The
precipitation will taper off this afternoon with mostly cloudy skies
and cool temperatures prevailing. Our next weather system arrives on
Saturday with breezy conditions and mainly rain showers as
temperatures climb to near normal levels.
Near term /until 6 am Saturday morning/...
as of 1010 am EDT Friday...fairly widespread light precipitation
continues from the Champlain Valley eastward this morning with
just clouds across the northern Adirondacks and Saint Lawrence
valley of New York. The light precipitation will continue through
mid-afternoon before tapering off. Temperatures are generally in
the 30s where its precipitating and we are left with light rain in
the Champlain and Connecticut River valleys and light rain and
light snow in between. Have adjusted grids to reflect colder
temperatures to support light snow over central Vermont with
observations and webcams showing light snow falling. Could see
around an inch of new snow in some spots and have updated to
reflect this slightly colder scenario for more light snow. High
temperatures were also adjusted down a bit as cloud cover should
not allow temperatures from moving too much higher today.
tonight...depth of moisture continues to slowly decrease with winds
becoming light terrain driven. Some areas of br/fog are possible
given the lighter winds and saturated low levels...especially during
the evening hours...before winds increase again ahead of our next
system. Have mention some chance pops toward morning with thermal
profiles supporting mostly rain showers...except near the summits.
Temps mainly in the 30s to near 40 overnight.
Short term /6 am Saturday morning through Sunday/...
as of 336 am EDT Friday...little overall change in the forecast
from previous versions as we head into the weekend with the main
feature being weak low pressure passing north of the Canadian
border on Saturday. Latest models continue to indicate abundant
low/mid level moisture with this system, but synoptic forcing is
rather weak so while we continue to highlight likely pops for rain
showers(mainly north), quantitative precipitation forecast will be light with temps pushing well
above seasonal normals into the mid/upper 40s east to mid 50s
west. By nightfall, the deepest low level moisture begins to shift
east as the low tracks off into the Canadian Maritimes and thus
precipitation will gradually taper off by Sunday morning.
Sunday's forecast has become a little more tricky though as high
pressure begins to build over the Great Lake region, but aloft
weak shortwave energy looks to intensify and dig out a trough over
southern Ontario. Models are showing some light quantitative precipitation forecast possible along
a washed out boundary draped across our central/southern zones
from saturdays low, but i'm hesitant to go with more than chance
pops with surface high pressure trying to build in. Temps will be
tricky as well depending on where the boundary sets up, but
thinking across central/northern areas highs will be slightly
below seasonal normals in the mid/upper 40s, with upper 40s to
possibly lower 50s south.
Long term /Sunday night through Thursday/...
as of 336 am EDT Friday...aforementioned high pressure over the
Great Lakes Sunday shifts east across the northeast for Sunday
night and Monday offering a dry and seasonally cool end to the
weekend and start of the work week. Thereafter, this mornings runs
of the GFS/CMC/ECMWF are in a little disagreement with our next
potential system developing out of northern plains Monday
afternoon. European model (ecmwf) and CMC stayed consistent to previous run tracks
taking the low north of Lake Superior Monday night to the tip of
James Bay by Tuesday night, while the GFS has trended a little
further south. All push a warm front through the area Tuesday with
the north country firmly in the warm sector through Wednesday
night, but the more southerly track of the GFS would offer higher
precipitation chances. Have stuck close to consistency from our
previous forecast highlighting some low chance pops with highs
Tuesday/Wednesday pushing back into the 50s area- wide as mean
925mb temps jump to +5-10c.
Aviation /14z Friday through Tuesday/...
through 12z Saturday...the aviation challenge is lowering
cigs/vis associated with low level moisture and potential IFR
conditions. Current obs show a mix of IFR at Rutland to MVFR at
mpv/slk/mss/btv and VFR at pbg. Current radar shows precip
redeveloping across the Champlain Valley with lowering cigs toward
IFR at btv. Expecting IFR cigs to prevail most of the morning
before lifting between 16-18z today at rut/btv/mpv/slk...as
northwest winds develop at 5 to 10 knots. Tonight...soundings
show additional moisture developing...especially slk/mpv with IFR
conditions possible...but these low clouds lift as winds increase
toward morning. Expect higher terrain to be obscured.
Outlook 12z Saturday through Tuesday...low clouds with IFR
conditions are possible through Saturday morning...before warm
front produces additional showers on Saturday across our northern
taf sites. Periods of MVFR cigs are possible. South to southwest
winds will increase with localized gusts to 30 knots possible at
slk/mss/btv. Surface cold front with a wind shift to the northwest
occurs on Sunday morning with mainly VFR conditions expected for
early next week.