Severe Thunderstorm Warning 32, NWS Caribou, ME

Area Forecast Discussion
National Weather Service Caribou ME
217 PM EDT Fri Aug 28 2026

.WHAT HAS CHANGED...
- Adjusted the POP timing for the rest of this afternoon with
  the cold front (FROPA) timing 60-90min faster than previously
  modeled.

&&

.KEY MESSAGES...
1) Showers and thunderstorms rest of this afternoon, some of
which may be strong with gusty winds and small hail.

2) System bringing rain showers and chance for thunder moves in
Sunday afternoon.

&&

.DISCUSSION...
KEY MESSAGE 1...Showers and thunderstorms today, some of which
may be strong with gusty winds and small hail.

KEY MESSAGE 1 DESCRIPTION...

Latest KCBW radar and satellite data shows two areas of showers
and thunderstorms. First area of storms are along a cold front
that is quickly moving through Northern Aroostook County
extending back to Moosehead Lake region. There is a secondary
area of storms extending from near Bangor and this is convection
developing along and just northwest of the marine layer
boundary. Temperatures in the 70s and low 80s between these two
boundary is allowing for SBCAPE to be around 1500j/kg, 18z CAR
RAOB indicating 2048j/kg of SBCAPE. There is 25-30kt of
indicated deep layer shear thanks to recent VWP scans. 18z CAR
RAOB confirms this thinking but given how fast this cold front
is moving storms are moving too fast to fully organize despite
the fairly modest mid-level lapse rates. Cannot rule out a few
thunderstorms that make it to severe levels but much of the
activity will be sub-severe with gusty winds and perhaps small
hail but the FZL is around 13kft.

KEY MESSAGE 2...System bringing rain showers and chance for
thunder moves in Sunday afternoon.

KEY MESSAGE 2 DESCRIPTION...
Low pressure system in Canada moves eastward this weekend, with
trough axis moving through Sunday afternoon. Cold front moves
through the state Sunday evening, funneling in some cooler air
behind it. Rain moves into the north, generally expanding
southeastward during the day Sunday. PWATs generally around
1-1.50 inches based on global and regional model outputs. Global
models are keeping precipitation chances pretty modest, around
14 of an inch, while regional models are hinting at some more
convective storms developing Sunday evening, bumping up rain
totals to one half to three quarters of an inch in isolated
locations, predominantly in the north and southeast. Instability
parameters include few hundred joules of CAPE, 40-50 kts of
effective shear, and some decent low level lapse rates,
indicating that a thunderstorm is not out of the question.
Heating ahead of the cold front in eastern Maine could aid in
initiating some convection along the boundary. Confidence is
still low for any severe thunderstorms to develop, given the
model disagreement, but regional models are hinting at better
instability parameters than earlier indicated.

&&

.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
Through 00z This Evening...IFR at BHB due to low cigs. VFR at
other terms. PROB30 for -TSRA or VCTS with ongoing TStorms. S
winds 5-15kt with gusts up to 20kt.

Tonight...IFR/LIFR at BHB due to FG then clears and becomes VFR
with FROPA. All other sites VFR FEW cigs or SKC by midnight as
skies clear. Light NW winds around 5 kts.

Saturday...VFR under SKC. W winds 5 to 10 kts.

Saturday night...VFR. Chance for valley fog, which would reduce
visibility. Light SW winds.

Sunday... MVFR/IFR in afternoon showers and thunderstorms at
northern terminals and KBGR. MVFR in showers possible at KBHB. W/SW
winds 5 to 10 kts.

Sunday night...MVFR with a chance of rain showers.
NW winds at 5 to 10 knots.

Monday...VFR. NW winds at 5 to 10 knots.

Monday night...VFR. Light and variable winds.

Tuesday...VFR. Winds E/SE at 5-10kt.

&&

.MARINE...
Winds/seas below SCA levels this weekend into early next week.
Seas 2 to 4 ft. Fog possible Saturday night. Slight chance for
rain showers Sunday night. Winds SW Saturday night into Sunday,
and shift W/NW by Monday.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.

&&

DISCUSSION...JS
AVIATION...JS