Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Caribou ME
307 PM EST Thursday Feb 11 2016
a weak upper level shortwave will move through northern areas
this evening. High pressure will briefly cross the region on
Friday. Low pressure will track south of the area Saturday as a
surface trough extends inland across our area.
Near term /through Friday/...
a small upper level shortwave crossing northern areas early this
evening will produce numerous snow showers. Accumulations of up
to an inch are possible in some localized areas across the north
central part of this region early tonight. As the shortwave moves
away later tonight, surface ridging will build in from the west.
High pressure briefly sliding over the area will bring a sunny to
partly cloudy start to the day on Friday. Clouds will begin to
increase late in the day ahead of a new, and more vigorous upper
level low diving in from the northwest.
Short term /Friday night through Sunday/...
likely significant norlun inverted trough snow event for late
Friday night through Saturday evening along the coast. Question
is...where along the coast. Model consensus puts the heaviest
precipitation near the east side of Penobscot Bay from Mount
Desert Island up through Bangor. However, different models and
model ensembles still say this band could set up about 75 miles
east or west of East Shore Penobscot Bay. Models however are
converging enough to a solution that felt comfortable enough to
put up a Winter Storm Watch from southern Penobscot into Hancock
County. It can't be emphasized enough that the location of this
narrow band of heavy snow is uncertain, and this is the type of
event where there will be a large difference in snow totals over
short distances. Snow ratios will run fairly high with a fluffy
low water content snow...the type of snow that you can brush off
your car with a broom. This, coupled with the north breeze, will
allow for areas of blowing snow as well where the snow actually
Other story is the very cold air. Wind chills will become an increasing
factor on Sunday, with wind chills to 30 below over the north.
Coldest airmass and coldest wind chills of the season.
Long term /Sunday night through Thursday/...
any precipitation from the weekend system should have departed by Sun night,
and upper ridging moving over New England will bring clearing skies
Sun night into Monday am as a surface ridge crosses the County Warning Area. The main
feature in the long term will be a low pressure system moving through
the middle-Atlantic into New England Tuesday into Wednesday. While models have
been in general agreement over the existence of this low, they
have differed greatly on the track and strength of upper and surface
features. However, with the 12z models, all 3 long- range
deterministic models appear to come into much better agreement.
Edits were needed to the superblend first guess, and were made
generally in the direction of the 12z GFS and CMC runs. The 12z
European model (ecmwf) concurred when it came in. With the good agreement, likely and
definite probability of precipitation were introduced across much of the County Warning Area Tuesday am through
Tuesday night. With models generally agreeing on a further west track
than previously fcst, temperatures have been bumped up Tuesday into Wednesday. Now
expecting a change to or mix with rain over almost the entire County Warning Area
by Tuesday night as the low tracks up the St. Lawrence Valley and S-southeast
winds draw warmer air well inland. As of now, it seems likely that
there will be significant marine issues, and coastal flooding may
be a concern Tuesday night into Wednesday. Snow will wind down on Wed, and
Thursday looks dry, though clouds may linger.
Aviation /18z Thursday through Tuesday/...
near term: MVFR conditions across the north this evening should
improve to VFR later this evening. VFR conditions are expected
across the north late tonight through Friday. VFR conditions are
expected downeast tonight and Friday.
Short term: generally VFR for through the weekend with the notable
exception of The Bar Harbor to Bangor area...perhaps stretching
northwest to Greenville. In this area, snow could bring conditions
down to IFR in the narrow corridor where the snow does occur.
near term: a Small Craft Advisory will be up tonight through
Friday morning for winds up to 30 knots. A freezing spray advisory
will also be up tonight into early Friday for moderate freezing
spray as colder air moves in over the waters.
Short term: small craft conditions developing again Saturday
afternoon and persisting into Sunday. Air will be cold enough for
moderate freezing spray Saturday night and Sunday. May even be
some heavy freezing spray, but don't have enough confidence yet to
go with a watch.
ME...Wind Chill Advisory from 3 am to 9 am EST Friday for mez001-
Winter Storm Watch from late Friday night through late
Saturday night for mez015-016-029.
Marine...Small Craft Advisory from 6 PM this evening to 1 PM EST Friday
Freezing spray advisory from midnight tonight to noon EST
Friday for anz050>052.