922
FXUS61 KCAR 050234
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
934 PM EST Wed Dec 4 2024

.SYNOPSIS...
Low pressure will rapidly approach from the west tonight and
cross the area Thursday. The low intensifies across the
Maritimes Fri. High pressure builds toward the region Saturday.
Low pressure tracks north of the region Sunday then exits
across the Maritimes Monday.

&&

.NEAR TERM /THROUGH THURSDAY/...
9:30 PM Update...Updated PoPs to account for latest trends.
Light snow is falling at Bangor, with reports of a coating of
accumulation. Also have had some light snow in Eastport with
south winds off the Gulf of Maine. Made minor tweaks to
temperatures, winds, and sky cover as well to account for latest
observations.

00z high-resolution guidance has indicated that the Bangor
region, Upper Penobscot Valley, and Interior Downeast could be a
bit colder than forecast tonight into Thursday morning. Will
continue to monitor and update as needed.

Previous Discussion... An upper level trough moving across the
Great Lakes tonight will become negatively tilted as it reaches
the coast on Thursday, leading to a rapid deepening of surface
low pressure as it crosses Maine and moves into the Canadian
Maritimes. The consensus low track bisects the area from about
Dover-Foxcroft through southeastern Aroostook County, although
some uncertainty still exists. To the south of the track, an
intensifying low level jet will bring mild maritime air rapidly
northward, changing precipitation from snow to rain early
Thursday morning and significantly limiting totals to generally
a slushy 1 to 3 inches. North of the low track, all snow is
expected. Totals will be influenced by terrain, with southeast
facing slopes seeing slightly more QPF and snowfall around the 8
inch warning criteria, while other areas across northern Maine
are most likely to see a general 4 to 6 inches. No changes to
the winter weather headlines were needed with the afternoon
update. A wind advisory was issued from 6z to 15z along the
coast as the low level jet transits the area from west to east.
Forecast soundings show an unstable profile across the low
levels owing to both the preceding cold air mass in place aloft,
as well as a combination of surface warm advection and
comparatively mild sea surface temperatures steepening low level
lapse rates. 925mb winds between 50 to 60 knots are forecast by
a consensus of guidance within the low level jet. The
aforementioned low level lapse rates will allow this to mix
towards the surface, with reduction factors resulting in wind
gusts of 40 to 50 mph for most coastal areas. Some of the higher
elevation, exposed areas near the immediate coast may see
slightly higher gusts. While it will be windy further inland,
the power outage risk should be limited by significantly less
snow load compared to the Thanksgiving storm due to temperatures
starting out below freezing and lower QPF and snow amounts.
However, the colder temperatures and wind will contribute to
more blowing snow and reduced visibility across the north,
especially for open areas.

Decreasing precipitation rates are expected Thursday afternoon
after 18z as the strongest PVA move east into New Brunswick and
modestly drier air above 500mb moves into the area. Another
round of stratiform snow is possible across the north just after
sunset as PVA along the west side of the trough and surface low
moves through. Additional significant accumulations are not
expected with this, but areas that receive more snow with this
round will see a greater risk of blowing snow over open areas
for the rest of Thursday night into Friday.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
A jet max will move around an upper level low and negatively tilting
upper trof Thursday night supporting an intensifying low across the
Gulf of Saint Lawrence. The surface/upper lows then vertically
stack overnight. Expect a chance of wrap-around snow showers
across the north and mountains Thursday night, with evening snow
showers across Downeast areas. The intensifying Gulf of Saint
Lawrence low will also create a tight pressure gradient across
the region which will support increasing west/northwest winds
through the night. Expect frequent 35 to 45 mph gusts, locally
stronger across favored higher terrain areas. A Wind Advisory
could be required, particularly across the north and mountains.
Blowing snow could also become a concern later Thursday night
with the increasing winds, particularly across the favored open
terrain areas of northern Maine. The vertically stacked system
lifts to Labrador Friday, while a disturbance rotating around
the system crosses the forecast area. Strong gusty, possibly
advisory level, west/northwest winds will persist Friday.
Blowing snow could also remain a concern. Could still have a
slight chance/chance of snow showers across the north and
mountains Friday. Otherwise, expect mostly cloudy/partly sunny
skies north with partly/mostly sunny skies Downeast. Upper level
troffing persists across the region Friday night, while another
disturbance moves through the trof. At the surface, the low
lifts north across Labrador while high pressure builds east
toward the region. Could still have a slight chance of snow
showers across the north and mountains Friday night. Otherwise,
expect partly/mostly cloudy skies north with mostly clear/partly
cloudy Downeast. Winds will also diminish with the weakening
pressure gradient. The upper trof begins to move east Saturday,
while surface high pressure builds toward the region. Generally
expect partly sunny skies north with mostly/partly sunny skies
Downeast. Expect below normal level temperatures
Friday/Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
High pressure will cross the region Saturday night. A clipper system
crossing Quebec province will draw a warm front toward the region
Sunday. Expect overrunning light snow will develop Sunday with light
snow accumulation possible. Snow should end across much of the
region Sunday night. However, snow showers could linger across
northern areas in advance of an approaching cold front. The cold
front should stall in the vicinity of the region Monday, though
exactly where is still uncertain. The front should begin to lift
back north in the form of a warm front later Monday into Monday
night with light overrunning precipitation again possible.
Uncertainty increases Tuesday into Wednesday. Due to the
uncertainty will keep chance to likely snow/rain showers for
now. Expect below normal level temperatures Sunday. Near
normal, to slightly above normal, level temperatures are
expected Monday. Above normal level temperatures are expected
Tuesday/Wednesday.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
NEAR TERM: IFR or lower at BGR through tonight. Elsewhere, VFR
through 04-05z. Then conditions deteriorate to IFR/LIFR at all
terminals by around 07z. Snow develops later tonight, changing
to rain at BHB then BGR early Thursday morning. SE winds 5-10
kt, increasing to 10-20kt with higher gusts late tonight into
Thursday morning. Higher gusts to 40 kt possible at coastal
airports such as BHB. LLWS is expected after 06-07z from BGR
northward and after 09z at BHB. LLWS gradually diminishes

SHORT TERM:
Thursday night...VFR/MVFR, occasional IFR, north with a chance
of snow showers. Patchy blowing snow north. Across Downeast
areas, occasional MVFR conditions possible early with a slight
chance of snow showers. Otherwise, VFR. West/northwest winds 10
to 15 knots with gusts up to 20 knots, increasing to 15 to 25
knots with gusts 30 to 40 knots.

Friday...VFR/MVFR, occasional IFR, north with a chance of snow
showers and patchy blowing snow. VFR Downeast. West/northwest
winds 20 to 30 knots with gusts 30 to 40 knots, with locally
stronger gusts.

Friday night...VFR/MVFR north with a slight chance of snow showers.
VFR Downeast. West winds 10 to 20 knots with gusts up to 25 knots,
diminishing to 10 to 15 knots with gusts up to 20 knots.

Saturday...VFR/MVFR north. VFR Downeast. West winds 10 to 15
knots with gusts up to 20 knots.

Saturday night...VFR. Variable winds 5 to 10 knots.

Sunday...VFR/MVFR early, then MVFR/IFR with light snow.
Variable winds 5 to 10 knots, becoming south/southeast around 10
knots.

Sunday night...MVFR/IFR early, then VFR/MVFR. Light snow tapering to
snow showers. South/southwest wind 5 to 10 knots.

Monday...VFR/MVFR early, then MVFR/IFR with a chance of snow and
rain showers. South/southwest winds 5 to 10 knots, becoming
southeast/east.

&&

.MARINE...
NEAR TERM: Winds and seas increase tonight with gale force winds
expected after midnight. A few gusts to storm force are possible
(roughly 50 percent chance) between 10-16z Thursday from west to
east, followed by a lull in winds, then an increase back to gale
force Thursday night. Seas will peak at about 8 to 11 feet. A
Gale Warning remains in place.

SHORT TERM: Gale conditions Thursday night into Friday night. Small
craft advisory conditions Saturday. Rain/snow showers early
Thursday night, then snow showers late.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Warning until 1 AM EST Friday for MEZ001-004-005-
     010.
     Winter Weather Advisory until 1 AM EST Friday for MEZ002-003-
     006-031.
     Wind Advisory from 1 AM to 10 AM EST Thursday for MEZ029-030.
MARINE...Gale Warning until midnight EST Friday night for ANZ050>052.

&&

$$


Near Term...Clark/MStrauser
Short Term...Norcross
Long Term...Norcross
Aviation...Clark/MStrauser/Norcross
Marine...Clark/MStrauser/Norcross