FXUS61 KCAR 081402

Area Forecast Discussion
National Weather Service Caribou ME
902 AM EST Fri Dec 8 2023

High pressure will cross the area today. A warm front will
approach tonight then cross the region Saturday. Intensifying
low pressure tracking across Maine will draw a cold front across
the region Sunday night into Monday. High pressure builds
Monday night into Tuesday.


902AM Update...Most of the clouds have cleared from the region,
so adjusted the sky forecast to show this. Otherwise, the rest
of the forecast looks good.

Previous Discussion:
Mostly clear skies persist across most of the forecast area
early this morning, though a few low level clouds remain across
northeastern Aroostook county, with occasional flurries found
within this patch of stratus. That said, high pressure will
continue to provide subsidence to the area, allowing for skies
to fully clear for the day today across the entire forecast
area. These clear skies will allow for as much incoming solar
radiation as possible with the low sun angles this time of the
year, but with persistent west to northwest winds advecting
cooler air into the region, highs today will only range from the
mid 20s across the north to around 30 along the Downeast coast.
Tonight, clear skies are expected to persist through the night,
and with recent snowfall across most of the CWA and winds
becoming light and variable, radiational cooling will allow for
temperatures to drop significantly. Current forecast is
assuming completely clear skies everywhere, though it is
possible a mesoscale band of stratus could develop off the St.
Lawrence today and remain stationary over parts of northern
Aroostook county tonight, which would mitigate the cooling
effect. There is moderate to high (77%) confidence in
temperatures dropping below zero across most of Aroostook
county, while temperatures fall into the single digits above
zero to low teens in the Downeast region.


A very active mid-term. First concern is potential for light
freezing rain or freezing drizzle late Sat/Sat night. Second
concern is a strong storm system late Sun through Mon with heavy
rain, strong wind, coastal flooding, flash freeze, and a small
snow potential.

Saturday/Saturday Night...
Decent warm advection from the SW and increasing/thickening
clouds. Late in the day and into Sat night, could be enough low
level moisture for some light precipitation or drizzle.
Temperatures north of Bangor will be near or just below freezing
with very light temps above freezing aloft, leading to the
potential for freezing drizzle/freezing rain. Precip amounts
look very light...less than 0.05"...but it doesn't take much
freezing drizzle or freezing rain to lead to travel impacts.
Think that the best shot at freezing precipitation, if any does
occur, is over the Central Highlands. Temperatures Sat night
will be slowly warming, with the freezing line creeping north to
around the St John Valley at dawn Sunday. The warm advection
over the snowpack will likely lead to a fair amount of fog
Saturday night.

Sunday to Monday...
A dynamic weather system is in store. High amplitude upper
trough will be approaching from the west, with strong southerly
fetch. A frontal boundary with a strong temperature gradient
will be moving east through the region, with surface low
development over Southern New England and rapid intensification
as it moves roughly over western Maine Mon morning.
Models/ensembles are in decent agreement, but there are some
crucial differences that will determine the ultimate impacts,
namely the speed/amplitude of the upper trough and exact track
of the surface low that develops and intensifies along the cold

Heavy Rain Threat...
There is fairly high confidence, and increasing confidence, in
heavy rain. Models/ensembles have been trending wetter, and
likelihood is there for 1.5-2.5 inches of rain, with the
potential for more. Precipitable water values in some of the
wetter model solutions are near all-time record levels for
December, with a strong plume of moisture from the south. And
there will likely be a front somewhere near us that will be the
focus for the heavy rain. While there is some uncertainty where
this sets up, likelihood exists for somewhere in the state to
exceed 2 inches of rain, with the best likelihood at this time
appearing to be over western portions of the forecast area,
especially the Central Highlands where orographic lift will play
a role. The heavy rain threat is from late Sun afternoon to Mon
morning. Adding to the concern is the snowpack that will be
melting off with the very mild temperatures and rain. Some
smaller river and streams could experience some flooding, but
the magnitude is still uncertain this far out. Don't believe
there is enough ice on the rivers yet for ice jams to be an

Wind Threat...
The wind threat is conditional on where the surface low tracks
along the front. If the low tracks west of our area, the whole
area could get strong, impactful winds from the south, but if
the low tracks over our area, the wind threat could be limited
to eastern portions of the area or even just over New Brunswick.
Odds favor strong wind at least for Washington County, but will
continue to monitor.

Coastal Flooding...
Think that coastal flood threat is fairly minor, mainly because
the surge of around two feet most likely comes a few hours
after the Mon morning high tide. Anticipate perhaps some minor
wave runup and splashover issues, but if the system were to
speed up and the surge and higher seas were to coincide with the
Mon morning high tide, it could be a more serious issue.

At this time, majority of models bring the heavier snow west of
our forecast area. However, were the front and low pressure to
set up further east, as a minority (<25%) of ensemble solutions
do show, there could be heavy snowfall mainly over western
portions of the forecast area. At this time, the most likely
scenario is a brief changeover to snow in the north/northwest
toward the end of the event Mon afternoon/evening with perhaps
an inch or two of snow.

Flash Freeze...
Roads could become icy Monday night as cooler air moves in
behind the system. Confidence in this is low at this time due to
uncertainty on the gap, if any, between precipitation ending
and temps falling below freezing.


Quieter weather Tue to Thu, with perhaps a weak system or two in
westerly flow. Temps should be fairly close to average.


NEAR TERM: VFR conditions expected to persist through the day
and into the night tonight across all terminals. NW winds 5 to
10 kts becoming light and variable. Slight chance (10%) of low
level stratus returning to northern terminals late this
afternoon into the night tonight, which would bring the return
of MVFR cigs.

Saturday...MVFR cigs developing Saturday afternoon. Light

Saturday night and Sunday...IFR to LIFR cigs with IFR vis in
fog Saturday night into early Sunday morning. Freezing drizzle
is possible Saturday night into early Sunday morning. South
winds steadily increasing towards 10 to 20 kt by later Sunday
afternoon. LLWS possible by Sunday evening.

Sunday night...IFR to LIFR cigs, IFR to LIFR vis in fog and
drizzle, LLWS expected. South winds increasing all night with
gusts over 35 kt possible by late night.

Monday...Mostly IFR to LIFR cigs. IFR vis in locally heavy rain.
LLWS continues. South winds possibly gusting over 35 kt in the
morning, becoming westerly 15 to 25 kt in the afternoon.

Monday night and Tuesday...MVFR cigs north of GNR and HUL,
otherwise VFR. Tempo IFR in snow showers north of GNR and HUL.
West winds 10 to 25 kt.


NEAR TERM: Winds and seas will remain below SCA conditions
through tonight. Occasional gusts to around 20 kts, especially
over the outermost portion of the coastal waters. Seas 1-2 ft.

SHORT TERM: Southerly Gales likely Sun night/Mon, with enough
confidence to go ahead and issue a watch. Can't rule out storm
force winds. Seas likely to build to close to 20 ft late Mon.
Conditions gradually improve Mon night/Tue as winds shift from S
to W/NW.


MARINE...Gale Watch from Sunday afternoon through Monday evening for



Near Term...AStrauser/LaFlash
Short Term...Foisy
Long Term...Foisy