End of November Winter Storm Update One
000
FXUS61 KCAR 290346
AFDCAR
Area Forecast Discussion
National Weather Service Caribou ME
1046 PM EST Sun Nov 28 2021
.SYNOPSIS...
Low pressure will develop south of the Gulf of Maine tonight, track
north across Nova Scotia Monday, and continue north across the Gulf
of Saint Lawrence Monday night into Tuesday. High pressure will
build south of the area Wednesday. Low pressure will track to our
north on Thursday followed by a strong cold front Thursday night and
Canadian high pressure Friday.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
Update...
Surface high pressure will ridge toward the region overnight.
At the same time, an approaching upper level trof will help
support the development of low pressure south of the Gulf of
Maine. Based on satellite trends, have increased cloud cover
across the forecast area overnight with this update. Expect
partly/mostly cloudy skies across the region overnight. Across
Downeast areas, could also have a chance of light snow late,
mostly toward the coast. Any snow accumulation overnight will be
less than an inch. Low temperatures will range from the upper
single digits to the lower teens north, to around 20 to the mid
20s Downeast. Have also updated to adjust for current conditions
along with overnight temperatures.
Previous Discussion...
Low pressure will take shape southeast of Southern New England
late tonight and track from there north across Nova Scotia on
Monday. We will be on the western fringe of this system. The NAM
continues to indicate that enough moisture may back around the
western side of the storm to bring an inch or two of light snow
to eastern areas while the GFS, ECMWF and Canadian models have
the whole system too far east to bring us anything except for a
very light accumulation in eastern Downeast areas. The low will
continue north through the Maritimes Monday night with any light
snow or flurries along the eastern edge of our forecast area
tapering off late at night. The low will intensify bringing an
increasing northwest wind overnight and pulling colder air into
the area as the sky begins to clear late at night from southwest
to northeast.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Low pres will be pulling off to the Maritimes Tuesday morning
w/the western edge of the snow band along the western NB-ME border
shifting to the east. The 12z NAM along w/the ECMWF show some
llvl convergence holding on w/some minor additional accumulation
right along the border through late morning. Things will clear
out into late afternoon a WNW breeze of 10-15 mph. The W wind
coming off the Laurentians could lead to some snow showers for
the western areas as well as portions of the St. John Valley and
Baxter State Park region into the early evening. The activity
shuts down later in the evening as weak high pres ridges across
the region w/some brief clearing and lighter winds. This will
lead to a cold night w/overnight lows in the mid/upper teens
down into the central areas, while downeast seeing lower 20s.
Areas across the nrn tier into the N Woods could see some
readings in the single numbers w/the snow cover.
The clearing looks to be short lived as clouds move in later at
night ahead of upper disturbance slated to move across the
region on Wednesday. This feature appears to be starved for
moisture and best forcing appears to be across the w and nw
areas. Stayed close to the daycrew`s thinking of 20-30% pops
across nrn 3rd of the CWA. Milder w/afternoon high temps getting
into the 30s all the way to the nrn ME border. High pres to the
s ridges across the region Wednesday night w/brief partial
clearing, but increasing clouds once again as the next system
apchs from the w. Temps will bottom out early, and then level
off a WAA and clouds take hold after midnight.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As stated by the midnight crew, a fast moving, clipper type
system is forecast to move across the region Thursday into
Thursday evening. This system looks like it will bring a round
of snow to the region initially on Thursday, and then as the
warmer air pushes n, snow will change to rain by late morning
for the central and downeast region, while northern areas will
hang on to some snow longer. The 12z mdl guidance including the
ECMWF and Canadian show the rain-snow line getting pinched from
about the Limestone back into the Chamberlain Lake region of N
Piscataquis County. N of that line, precip looks to stay all
snow w/measurable snow. The GFS and some of its ensemble
members show a warmer solution warmer air(rain/snow line)
pushing all the way to the nrn border. Attm, leaned closer to
the ECMWF and Canadian solution w/the latest NBM supporting this
setup. Colder air to swing back into the region Thursday night
w/rain changing back to a period of snow or snow showers before
ending late at night. The ECMWF and Canadian and their
respective ensembles show portions of nrn and wrn areas seeing
up to 4" of snow before ending. It will be interesting to see
how the later runs treat this upcoming system.
Friday will be much colder and rather windy w/a WNW wind of
10-20 mph and higher gusts as the upper trof swings across the
region. Plus, snow showers and streamers possible possible
during the day. Much colder for Saturday into Sunday w/high pres
building in from the w. Daytime temps both days look to be
below normal for 1st week of December.....
posted by Advackia at 8:48 PM
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