NWS Caribou, Maine Area Forecast Discussion
568
FXUS61 KCAR 090938
AFDCAR
Area Forecast Discussion
National Weather Service Caribou ME
538 AM EDT Mon Mar 9 2026
.WHAT HAS CHANGED...
- (508 AM Update): Updates to the climate section based on today`s forecast.
- Winter Storm Watch issued for northern Maine where heavy mixed
precipitation is possible Wednesday through Thursday morning.
- Increased sleet amounts compared to the NBM across northern Maine.
&&
.KEY MESSAGES...
1) Heavy mixed precipitation is likely across northern Maine
Wednesday into early Thursday. Significant accumulations of
snow, sleet, and freezing rain are possible and could result in
travel impacts and isolated power outages.
2) Temperatures will remain unseasonably warm through Tuesday
resulting in snow melting, and ice rotting on rivers and lakes.
3) Two additional storm systems are likely to bring snow or
wintry precipitation to all or most of the forecast area, the
first Friday night into Saturday, then the second Sunday
afternoon into Monday. Both of these systems have the potential
to disrupt travel. The second system has potential for
additional impacts from strong south winds depending on its
track.
&&
.DISCUSSION...
KEY MESSAGE 1...Heavy mixed precipitation is likely across
northern Maine Wednesday into early Thursday. Significant
accumulations of snow, sleet, and freezing rain are possible and
could result in travel impacts and isolated power outages.
KEY MESSAGE 1 DESCRIPTION...
Significant mixed precipitation is likely Wednesday into early
Thursday as high pressure north of the area reinforces cold air
across the low levels ahead of an upper level trough over the
Great Lakes. The approach of this trough and its surface low
will lead to warm air advection aloft across Maine. Strong
isentropic lifting is expected with unseasonably high
precipitable water values in excess of 1 inch expected to
override the cold low level air across the north. 0Z model
guidance has come into slightly better agreement regarding
precipitation types with a majority of ensemble members and
guidance, but not all, favoring a surface low track over the
state instead of to the north. While some uncertainty remains
regarding the finer details of the sleet, snow, and freezing
rain transition zones, there is moderate confidence in the
general idea that all or nearly all rain is favored over the
southern half of the area, with a zone of at least moderate
icing possible around the Katahdin Region into southern
Aroostook County. Farther to the north snow will transition to
sleet, with the most significant snow accumulations across the
Saint John Valley and most significant sleet accumulations
favored in between. It is worth noting that while AI models have
sided with colder solutions, historically the initial cold air
advection prior to the switch in wind direction has been
slightly less robust than modeled in similar events, resulting
in precipitation type transition zones farther to the north of
models. Models also frequently struggle to depict the low level
refreezing layer appropriately, underestimating sleet. Some
adjustments were made to precipitation types to lower snow and
freezing rain probabilities and raise sleet probabilities
compared to the NBM.
Regardless of exact precipitation types, guidance favors 1 to
1.5 inches of liquid equivalent wintry precipitation across the
north, which meets the threshold for a Winter Storm Watch.
Travel impacts are likely, especially for the Wednesday
afternoon and Thursday morning commutes. Light snow and sleet
may start as early as the Wednesday morning commute also, but
greater impacts are expected later in the day into Wednesday
night. Ice accumulations locally up to a half inch are possible,
but these are currently favored mainly over the North Woods
where cold air damming is anticipated and higher elevation will
not allow the refreezing layer to be as deep for sleet. However,
the zone of greatest icing remains uncertain and may shift to
more populated areas, in which case some power outages cannot be
ruled out. The forecast will continue to be refined as the low
track comes into focus over the next 24 to 36 hours.
KEY MESSAGE 2...Temperatures will remain unseasonably warm through
Tuesday resulting in snow melting, and ice rotting on rivers and
lakes.
KEY MESSAGE 2 DESCRIPTION...
We will remain in a warm air mass today and Tuesday as high pressure
along the East Coast continues to funnel warm and relatively humid
air north across our region. High temperatures today will top 50 in
most inland sites, and on Tuesday will again climb over 50 in all
but far northern areas. The warm temperatures combined with some
sunshine at times will cause the snow pack to compact and continue
to melt. Some ponding in low lying areas may result from the snow
melt.
The softening of the river ice combined with some possible rises on
the rivers due to snowmelt may result in movement of ice Downeast
and in the Lower Penobscot and Kenduskeag Valleys. This could lead
to some ice jams early this week. Across the north, the ice will
continue to rot but will likely remain in place with little or no
significant movement expected.
KEY MESSAGE 3...Two additional storm systems are likely to bring
snow or wintry precipitation to all or most of the forecast
area, the first Friday night into Saturday, then the second
Sunday afternoon into Monday. Both of these systems have the
potential to disrupt travel. The second system has potential for
additional impacts from strong south winds depending on its
track.
KEY MESSAGE 3 DESCRIPTION...
An active pattern will set up this weekend into early next week
with two additional systems likely to impact travel. The first
on Friday night into Saturday is currently favored (roughly 60
percent of members) to track along the coast as a vigorous
shortwave trough exits the Great Lakes. This scenario would
result in a moderate snowfall across nearly the entire area,
with the heaviest amounts across central and Downeast areas. A
large minority of guidance tracks the low farther to the
northwest, which would result in a large dry slot moving over
the area, leading to less precipitation. This solution would
also be warmer with some potential for mixing closer to the
coast.
A second system is also likely Sunday night into Monday as a
longwave trough pivots across the Great Lakes, leading to
another surface low moving northeast from the Great Lakes. This
system is very likely to be stronger than the early weekend
system, but its track varies significantly which will determine
impacts. If a stronger low tracks west of the area, which is
currently the slightly favored solution, a strong south wind
could lead to issues, especially along the coast. Precipitation
will likely start frozen regardless of the track, especially
away from the coast, so at least some travel impact is looking
likely from this system.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Today...VFR conditions are expected at all sites. Some W wind
shear at 2K ft expected early this morning followed by SW wind
shear at 2K ft this afternoon. Winds SSW around 10 kt.
Tonight...VFR all sites except possibly dropping to MVFR over the
far north late. SW wind shear at 2K ft. SW winds around 5 kt.
Tuesday...VFR over southern sites. MVFR across the north. Winds SW
around 5 kt across the south and NW around 5 kt over the north.
Tuesday Night...Becoming VFR at northern sites and MVFR at
southern sites. N winds 5 to 15 kts.
Wednesday to Wednesday Night...Deteriorating to MVFR/IFR with
rain south and mixed precipitation north. E winds 5 to 10 kts
with gusts to 20 kts.
Thursday to Thursday Night...Improving to VFR. W winds around 10
kts with gusts to 25 kts.
Friday...Predominantly VFR. W winds 5 to 10 kts with gusts to 20
kts possible.
&&
.MARINE...
A SCA will be up for the offshore waters this morning, then for both
the offshore and intracoastal waters this afternoon through tonight
for SW winds gusting up to 30 kt. Winds should drop below SCA early
Tuesday. Seas building up to 6 ft today then 7 ft tonight and
dropping below 4 ft on Tuesday.
Winds and seas will increase to Small Craft Advisory thresholds
on Wednesday before winds likely increase to Gale force
Wednesday night through Thursday evening over the outer waters,
and possibly over the intracoastal waters as well. Another
period of gales is possible Friday night into Saturday and again
Sunday night to Monday.
&&
.CLIMATE...
A record high of 60 degrees was set in Bangor yesterday.
Daily high temperatures approaching records are possible
again today and tomorrow.
Monday, March 9
Caribou: Forecast 49 F; Record 47 F set in 1998
Houlton: Forecast 53 F; Record 53 F set in 2012
Millinocket: Forecast 52 F; Record 57 F set in 2016
Bangor: Forecast 56 F; Record 59 F set in 2016
Tuesday, March 10
Caribou: Forecast 43 F; Record 55 F set in 1977
Houlton: Forecast 56 F; Record 58 F set in 1977
Millinocket: Forecast 55 F; Record 54 F set in 2016
Bangor: Forecast 60 F; Record 62 F set in 1977
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Watch from Wednesday morning through Thursday
morning for MEZ001>006.
MARINE...Small Craft Advisory until 8 AM EDT Tuesday for ANZ050-051.
Small Craft Advisory from 1 PM this afternoon to 8 AM EDT
Tuesday for ANZ052.
&&
$$
DISCUSSION...MB/MWS
AVIATION...MB/MWS
NWS CAR Office Area Forecast Discussion
