123
FXUS61 KCAR 272127
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
527 PM EDT Thu Jun 27 2024

.SYNOPSIS...
A cold front will exit across the Gulf of Maine early tonight.
High pressure builds in through Friday, then slowly exits to
the east through Saturday. A warm front lifts to the north
Saturday night, followed by a cold front crossing the region
from Sunday into Sunday night. High pressure then builds in
through Tuesday.
&&

.NEAR TERM /THROUGH FRIDAY/...
A cold front currently approaching the Downeast coast will exit
across the Gulf of Maine early tonight. Aloft, an upper level
trof will cross the region tonight. Cold air aloft with the
upper trof will support steep lapse rates early tonight leading
to increased instability. Expect scattered/numerous showers,
along with isolated thunderstorms, across the forecast area
early tonight with the upper trof and exiting cold front. With
the cold air aloft, small hail could also possibly occur with
any stronger thunderstorms. Showers then diminish later this
evening, most persistent across northern areas with the upper
trof. Showers end regionwide overnight along with decreasing
clouds while high pressure begins to build toward the region.
High pressure then builds across the region Friday with
sunny/mostly sunny skies. Low temperatures tonight will range
through the 40s north, to around 50 to the lower 50s Downeast.
High temperatures Friday will range from the upper 60s to around
70 north, to the lower 70s Downeast.
&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
Northern stream shortwave ridging transits the area with associated
subsidence keeping things dry. Increasing high clouds will limit how
cool it gets, but still expect lows to fall to around 5 degrees
below normal.

The models differ on how quickly any precipitation builds in ahead
of the next system on Saturday. It appears another weak northern
stream shortwave ridge passes in the morning followed by a
shallow northern stream shortwave approaching in the afternoon.
The high resolution guidance is less bullish than the global
models. Tend to lean towards high resolution models within 60
hours and during summer, so pops leaned in their direction
keeping areas along and S/E of a Greenville to Weston Line dry
and limiting likely pops to along the western boarder with
Quebec late in the day. Precip appears intially to be warm
advection and not convectively driven (idea supported by no
progged CAPE and showalter indices of 5-12), so no thunder in
the forecast for Saturday. Highs on Saturday should be a few
degrees below normal.

Low to mid level warm advection coupled with a passing northern
stream shortwave will bring moderate rainfall to the region Saturday
night, quickly moving in from NW to SE Saturday evening. As with the
past few events, highest QPF amounts will be focused over Downeast
Maine, but with amounts forecast under an inch, no significant
hydrologic impacts are expected. Lows Saturday night should be
near normal.

Sunday appears it could feature two rounds of precipitation the
first in the morning as the warm advection tapers off and the
shortwave finishes exiting to the east (this should mainly be
over Downeast Maine). The second should be in the afternoon
ahead of a cold front and associated upper support behind it.

With on average around 1000-2000 J/kg of CAPE 40-50KT of bulk
shear and the region in the right rear quadrant of a 115kt+ jet
Sunday afternoon there is the potential for strong to possibly
severe thunderstorms. Main threat would be from strong to
possibly damaging wind gusts. In addition locally heavy rainfall
could produce localized flooding of know poor drainage and low
lying areas. The risk of thunderstorms will be addressed in the
HWO.

Highs on Sunday should be around 5 degrees above normal across
the North and near normal across Downeast and the Bangor Region.
&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A slow moving northern stream trough slowly crosses the area
Sunday night and Monday. Have slight chance pops (except for
chance coastal Downeast Sunday evening) to address any showers
from this. However with drying in the low than mid levels - not
sure how much precipitation will actually occur.

Deep layered ridging builds in Monday night-Tuesday night.
Associated subsidence should keep things dry. A possible
wrinkle to this is some models showing a cutoff low developing
near Cape Cod Monday night/Tuesday - depending on exactly where
it develops and tracks - this could bring some showers to
Downeast Maine Monday night/Tuesday. Most likely though this
stays far enough offshore not to have any impact, if it develops
at all.

Models then differ on timing for the next system that tracks
across Northern Ontario and Quebec Wednesday and Thursday. The
GFS (as is its bias) is the most progressive while the CMC and
ECMWF are slower. For now limit pops on Wednesday to slight
chance across portions of the North, then have slight chance
pops everywhere except for chance pops in a portion of N
Somerset Wednesday night. For Thursday introduce chance pops for
everyone basically from the Central Highlands/Upper Penobscot
Valley on north.

Temperatures should be near normal Sunday night and Monday,
below normal Monday night, then above normal Tuesday-Thursday.
&&

.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
NEAR TERM: Variable conditions, ranging from VFR to IFR, early
tonight with showers and isolated thunderstorms. VFR overnight
with showers ending. VFR Friday. Variable winds 5 to 10 knots,
becoming west/northwest 10 to 15 knots tonight. Northwest/west
winds 10 to 15 knots with gusts 20 to 25 knots Friday.

SHORT TERM:
Friday night-Saturday...VFR, except for very low chance of MVFR
late Saturday at far NW terminals. S winds G15-25KT possible
Saturday.

Saturday night-Sunday morning...IFR or lower probable. LLWS
likely. South winds 10 to 20 kt. LLWS likely Saturday night.

Sunday afternoon/evening...Becoming VFR with periods of MVFR or
lower possible in any stronger thunderstorms. NW winds G15-20KT
possible.

Late Sunday night-Tuesday...VFR.
&&

.MARINE...
NEAR TERM: Winds/seas below small craft advisory levels tonight
through Friday. Isolated/scattered showers early tonight.

SHORT TERM: Sub-SCA conditions on all waters Friday night. SCA
conditions are then probable on Saturday, then likely Saturday
night and Sunday on all waters. SCA conditions could linger
into Sunday night. Sub-SCA conditions are then forecast Monday-
Tuesday.
&&

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

&&

$$


Near Term...Norcross
Short Term...Maloit
Long Term...Maloit
Aviation...Norcross/Maloit
Marine...Norcross/Maloit