NWS Caribou, Maine Area Forecast Discussion
387
FXUS61 KCAR 012352
AFDCAR
Area Forecast Discussion
National Weather Service Caribou ME
752 PM EDT Wed Apr 1 2026
.WHAT HAS CHANGED...
Update for 00z aviation discussion
- Have hoisted a Winter Storm Watch for Northwest and Northeast
Aroostook County from Thursday night to Friday midday.
Combination of snow, sleet and freezing rain to bring the
potential of significant impacts.
- Increased snow, sleet and freezing rain totals areawide for
Thursday night into Friday with increasingly good agreement in
the ensembles.
- Increased winds and wind gusts on Friday with increased
pressure gradient.
&&
.KEY MESSAGES...
1) Widespread wintry precipitation late Thursday through Friday
evening, which could greatly impact Thursday evening, Friday
morning commutes.
2) Another low pressure system moves through region this
weekend, bringing potential for another round of
snow/rain/freezing rain, that could impact travel.
&&
.DISCUSSION...
KEY MESSAGE 1...Widespread wintry precipitation late Thursday
through Friday evening, which could greatly impact Thursday
evening, Friday morning commutes.
KEY MESSAGE 1 DESCRIPTION...
Setup...A surface low-pressure system, associated with 500mb
shortwave energy, will track into the Great Lakes. Meanwhile,
surface high pressure developing north of the Gaspe Peninsula
will establish a cold air damming (CAD) pattern at the surface
with light east winds. Thursday evening, a warm front will lift
north into Maine, riding up and over the cold air as
temperatures aloft at 750mb rise above freezing. PWATs will
increase to 1.5-2 sigma overnight as moisture advects
northeastward. Expect precipitation to break out across the area
from southwest to northeast. Surface winds will shift to the
S-SE into Friday morning, beginning to erode the boundary layer
CAD from south to north, aided by the increasingly warm April
sun angle. A cold front will cross the area Friday evening,
bringing an end to the precipitation.
PTypes and Timing...As mentioned, PWATs will increase due to
warm air advection aloft, reaching 1.5-2 sigma overnight and
2-3 sigma on Friday. Thursday evening temperatures will be in
the mid to upper 20s north, 28-31F for the Central Highlands
and Bangor Region, and 30-32F along the Downeast coast.
Precipitation will start around 9 PM to midnight across much of
the CWA, reaching far Downeast by 2 AM Friday. Initially, a mix
of snow, sleet, and freezing rain is expected along the Downeast
coast northward to The Airline (Route 9) and the Bangor Region,
which may create slippery travel overnight. North of there,
precipitation will initially develop as snow (with a few inches
possible) before mixing.
The 750mb warm nose will rapidly increase over a deep cold
pool. Hi-Res CAM soundings are in fairly good agreement
regarding the sleet and freezing rain transitions. The initially
shallow 750mb warm layer will gradually deepen, leading to a
transition from sleet to freezing rain. Toward daybreak, winds
will shift to the SE as the CAD erodes. This will change the
Downeast coast and Bangor area to plain rain, while freezing
rain continues along Route 6 from Greenville to Topsfield. North
of there, a prolonged period of sleet is expected from the
Baxter Region to the St. John Valley. By mid-morning, continued
erosion of the CAD will bring all rain to the Bangor Region,
Dover-Foxcroft, and Lincoln, encroaching on Topsfield to Houlton.
The combination of the warm April sun angle and strengthening
SE winds (gusting 15-25 mph) will erode the remaining CAD,
turning the entire CWA to rain by mid-afternoon. Rain will
continue into the evening until a dry slot works north ahead of
the cold frontal passage, as the low tracks to our north in
Quebec. Precipitation may briefly switch back to snow in the St.
John Valley, perhaps leaving an additional dusting. This could
lead to a flash freeze across northern zones as temperatures
fall quickly back below freezing.
Accumulations...Snow will be mainly confined to the north, with
2-4 inches (potentially up to 5 inches) expected in the St.
John Valley, Route 11 north from Oxbow to Portage and the
Caribou/Presque Isle areas. The Baxter Region to Houlton and the
Moosehead Region can expect 12 inches, while areas further
south will likely see only a minor dusting. There is potential
for significant sleet accumulations (0.2-0.5 inches) from the
Central Highlands into Northern Maine.
The main uncertainty lies in freezing rain totals, which depend
heavily on the strength of the CAD and the increasing sun angle
by the time precipitation falls as freezing rain in Northern
Maine on Friday. Up to a glaze of ice is possible from just
inland of the Downeast shoreline northward to Southern Aroostook
County. Up to a tenth of an inch of ice is possible across
Northern Maine, with up to a quarter-inch possible in the
Greenville area and North Woods.
The greatest chance of heavy mixed precipitation reaching
warning criteria exists in Northwest and Northeast Aroostook
County, so a Winter Storm Watch has been issued there from
Thursday evening to midday Friday. South of this watch,
additional Winter Weather Headlines will likely be needed for
travel impacts, but we are holding off for now due to lingering
uncertainties.
Impacts...Travel will become slippery nearly areawide late
Thursday evening due to snow, sleet, and freezing rain.
Untreated surfaces will cool down significantly Thursday night,
leading to slick conditions. As temperatures warm overnight in
Downeast areas, travel will gradually improve as surfaces become
slushy, and eventually wet. Friday morning, conditions will
improve from the Bangor Region northward, reaching Northern
Maine by midday. The increasingly warm April sun angle will
allow surfaces to heat up and turn wet. The greatest concern for
the Friday morning commute will be from the Bangor and Calais
regions northward to the St. John Valley. Drivers should
anticipate slippery roads, leave extra braking distance, and use
caution when walking on untreated surfaces.
KEY MESSAGE 2...Another low pressure system moves through
region this weekend, bringing potential for another round of
snow/rain/freezing rain, that could impact travel.
KEY MESSAGE 2 DESCRIPTION...
A large upper level trof will develop a large surface low
Saturday night through Sunday. Both ensemble models and
deterministic have come into very good agreement with the track
and timing of the low moving through the region. Precipitation
starts as snow in the north, and rain in the Central Highlands,
southwards. As warm air aloft advects in, chance for some
freezing rain/sleet, mainly in the Central Highlands,
northwards. As sun rises and temperatures increase, all
precipitation transitions over to rain. All models are
consistent in both anticipating a round of precipitation to
occur in the north Saturday night into Sunday, and another round
of precipitation throughout the state Sunday into Sunday night
ahead of moving in cold front. Continue to monitor the forecast
for updates, as precipitation types could heavily depend on
pressure system tracks.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Tonight...MVFR/IFR conditions for Aroostook terminals at times
overnight. Downeast terminals to see mostly VFR but cannot rule
out MVFR cigs toward daybreak. MVFR vsbys north with possible
IFR at FVE and CAR late. Winds light north, becoming variable
late.
Thursday...MVFR in the morning for the north and VFR in the
south. Once the patchy fog and low clouds clear in the north,
VFR for all terminals. Light and variable winds.
Thur night...MVFR/IFR for all terminals in SN/FZRA/IP. SE winds
5-15 kts.
Friday...IFR/LIFR in the morning. SN/FZRA/IP expected from BGR
northward with -RA at BHB. IFR/LIFR at northern terms due to
FZRA/IP changing to -RA with -RA at BHB and BGR. Late day
improvements to MVFR at southern terms. SE winds 10-15kt
gusting up to 25kt shifting S in the afternoon. LLWS possible.
Friday night...IFR north becoming MVFR with MVFR becoming VFR
south. VCSH/-SHSN possible at northern terms. Wind shift
expected between 05-08Z. Winds SW 5-15kt gusting up to 20kt
shifting to the N-NNW 10-15kt.
Saturday...VFR becoming MVFR late day. NE winds 5-15kt.
Saturday night...IFR/LIFR with SN/IP/FZRA at northern terms with
SN/RA at BGR and RA at BHB. SE winds 10-20kt gusting up to 30kt.
LLWS possible.
Sunday...MVFR/IFR with RA likely. S winds 10-15kt gusting up to
30kt. LLWS possible.
Sunday night...MVFR/IFR and RA early becoming VFR late night.
Winds shift W 5-15kt.
Monday...VFR. Low chance of MVFR due to SHSN at northern terms.
W-NW winds 10-15kt.
&&
.MARINE...
A Small Craft Advisory continues through tonight and into
Thursday. Seas 4-7 ft. Winds and seas calm by Thursday afternoon
and into early Thursday night. A SCA will be needed for later
Thursday night as wind gusts increase to 25 kts.
Small Craft Advisory conditions expected Thursday night into
Friday evening with gusty S winds and seas around 5ft. Winds
shift Friday night and expecting SCA conditions into Sun night.
Sat winds from NW shifting NE. Winds S on Sun and W on Sun
night. Low possibility of brief gusts to Gales Sunday on the
outer waters 15-25nm offshore. SCA may need to continue Monday
due to swells. Looking at precip/vsby...expect rain to reduce
vsby at times Thurs Night into Friday. Rain again Sat night into
Sun night.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Watch from Thursday evening through Friday
afternoon for MEZ001-002.
MARINE...Small Craft Advisory until 2 PM EDT Thursday for ANZ050-051.
Small Craft Advisory until 2 AM EDT Thursday for ANZ052.
&&
$$
DISCUSSION...ARL/JS
AVIATION...21/ARL/JS
NWS CAR Office Area Forecast Discussion
