NWS Caribou, Maine Area Forecast Discussion
267
FXUS61 KCAR 030102
AFDCAR
Area Forecast Discussion
National Weather Service Caribou ME
902 PM EDT Thu Apr 2 2026
.WHAT HAS CHANGED...
- Updated aviation discussion.
&&
.KEY MESSAGES...
1) Widespread wintry precipitation late tonight through Friday
midday, will greatly impact travel tonight into Friday morning.
2) Another period of significant sleet is expected across
northern Maine, with some freezing rain and snow also possible
Saturday night into Easter Sunday. Difficult travel is possible
across northern areas for Easter Sunday morning.
&&
.DISCUSSION...
KEY MESSAGE 1...
Widespread wintry precipitation late tonight through Friday
midday, will greatly impact travel tonight into Friday morning.
KEY MESSAGE 1 DESCRIPTION...
Setup...A surface low-pressure system, associated with 500mb
shortwave energy, will track into the Great Lakes tonight.
Meanwhile, surface high pressure north of the Gaspe Peninsula
will establish a cold air damming (CAD) pattern at the surface
with light east winds tonight. This 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 with a brief changeover
possible.
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. Tonight 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 midnight across much of the CWA, reaching far
Downeast by 2-3AM 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 into the early AM hours. 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 to Caribou area, 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
2-5 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 1-2
inches, while areas further south will likely see only a minor
dusting. There is potential for significant sleet accumulations
0.5 up to 1.0 inch 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 Warning remains in effect from 11PM
this evening till 5PM Friday. Conditions will rapidly improve
during the day so it is possible the warning will be cancelled
sooner. For the Central Highlands, Far Eastern, North Woods, and
Penobscot Valley Maine a Winter Weather Advisory remains in
effect from 11PM this evening to 2PM Friday. Lastly, Coastal
Downeast, Interior Downeast and Bangor Region are under a Winter
Weather Advisory from 11PM this evening till 10AM Friday.
Impacts...Travel will become slippery nearly areawide late
tonight due to snow, sleet, and freezing rain. Untreated
surfaces will cool down significantly tonight, 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 period of significant sleet is expected across
northern Maine, with some freezing rain and snow also possible
Saturday night into Easter Sunday. Difficult travel is possible
across northern areas for Easter Sunday morning.
KEY MESSAGE 2 DESCRIPTION...
In a very similar setup to the system tonight into Friday,
another warm front will lift across the area later Saturday
night into Sunday as low pressure passes to the northwest. This
low is favoring a slightly stronger intensity with a track
farther to the northwest, which should lead to slightly warmer
temperatures and keep wintry precipitation types away from
coastal and Downeast areas. While there is some uncertainty, the
general pattern strongly favors significant sleet/ice pellets
across far northern areas, with potential for 1 to 3 inches of
sleet and perhaps an additional inch or two of snow on top of
the sleet, mainly across the Saint John Valley. Freezing rain is
also possible, with the greatest ice accretion potential across
the Central Highlands into the North Woods, where higher
elevations will cause less depth of the refreezing layer.
Lighter accumulations of a combination of sleet and freezing
rain are likely for central areas east of the Central Highlands.
The NBM, likely due to the ECMWF/EPS systematic bias against
ice pellets, was too low with sleet probabilities again. Sleet
probabilities were increased compared to the NBM, with
compensatory decreases to snow and freezing rain probabilities,
especially early during the event Saturday night across northern
Maine. Any period of snow will likely be brief, with
significant reductions in snow ratios made compared to the NBM
to 10 to 1 or less due to potential for riming near the warm
nose aloft and generally poor conditions for snow growth with
strong winds aloft and very little correlation between lift and
the DGZ.
Travel impacts are likely north of Bangor for a period Saturday
night, with improvement from south to north Sunday morning. By
8AM Sunday morning, the greatest probabilities for sleet and
freezing rain will be north of Baxter State Park as temperatures
rise or remain above freezing to the south. The greatest impacts
to travel Easter morning are expected across this area,
especially northern Aroostook County where significant sleet
accumulations are expected into the morning. Precipitation is
expected to change to rain everywhere around mid-morning as
temperatures climb above freezing.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
Tonight...VFR/MVFR early, lowering to IFR/LIFR. A wintry mix of
snow, sleet and freezing rain developing. Precipitation
possibly starting to change to rain late along the Downeast
coast. Variable winds 5 to 10 knots, becoming southeast 10 to 15
knots with gusts up to 20 knots.
Friday...IFR/LIFR. A wintry mix changing to rain, from south to
north, through the morning and afternoon. Southeast/south winds
10 to 20 knots with gusts up to 25 knots. Southwesterly low
level wind shear developing during the afternoon.
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: MVFR possible early, mainly at northern terminals.
Otherwise VFR. NE winds 5-15 kts.
Saturday night to Sunday: VFR early, becoming IFR/LIFR with +PL
at northern terminals, mixing with SN at the onset and FZRA
Sunday AM before changing to -RA. -PL at central and southern
terminals changes to -RA late Saturday night or early Sunday
morning. All -RA is expected at coastal terminals such as BHB.
SE winds 10 to 15 kts with gusts to 30-35 kts possible. LLWS
possible.
Sunday night: MVFR possible at northern terminals, otherwise VFR.
WSW winds around 10 kts gusting to 20 to 25 kts.
Monday: Low VFR ceilings, with a chance of MVFR at northern
terminals. WNW winds around 15 kts with gusts to 25 to 30 kts.
Monday night to Tuesday: VFR. NW winds 5 to 15 kts.
&&
.MARINE...
A Small Craft Advisory has been issued for the Coastal Waters
out 25nm from 5AM Friday to 2PM Saturday. Southeast winds
Friday, shift southwest Friday night then North on Saturday.
Winds 15 to 25 kt with gusts up to 30 kt and seas 4 to 7 ft
expected. The Small Craft Advisory may need to be extended with
later updates.
Small Craft Advisory winds and seas are expected through Sunday
evening. Gale force winds are also possible (60 percent chance
over outer waters, 40 percent over the intracoastal waters)
later Saturday night into Sunday morning. Winds will be first to
decrease Sunday night, but seas will remain elevated through
much of the night, especially over the outer waters. Winds and
seas fall below advisory levels Tuesday into mid-week.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Warning until 5 PM EDT Friday for MEZ001-002.
Winter Weather Advisory until 2 PM EDT Friday for MEZ003>006-
010-011-031-032.
Winter Weather Advisory until 10 AM EDT Friday for MEZ015>017-
029-030.
MARINE...Small Craft Advisory from 5 AM Friday to 2 PM EDT Saturday for
ANZ050-051.
&&
$$
DISCUSSION...MWS/JS
AVIATION...MWS/JS/CN
NWS CAR Office Area Forecast Discussion
