-- Discussion containing changed information from previous version are highlighted. --
409
FXUS61 KCAR 212202
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
602 PM EDT Tue May 21 2024

.SYNOPSIS...
Weak mid and upper level features cross the area through midweek
as surface high pressure remains along the eastern seaboard. A
strong cold front will cross the area Thursday, followed by high
pressure Friday into the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
6:02 PM Update: Convection moving slowly east/northeast out of
VT/NH has weakened significantly as it pushes into western
maine. No lightning strikes this afternoon into early this
evening across the FA, and in fact even a lone shower has been
difficult to come by. The convection off to our west is
expected to weaken this evening with the loss of daytime
heating. No significant changes other than to remove most of the
thunder for this evening as the forecast remains on track.

Previous discussion:
A weak dew point boundary has slipped south into northern Maine
this afternoon which has knocked back dew points 5-10 degrees
across the north in Aroostook County. This boundary is
associated with more cloud cover but still seeing good thermal
heating under the clouds. Across the Central Highlands to the
Downeast coast is mostly sunny skies with strong heating.
Confidence in thunderstorm initiation is greatly reduced based
on the trends of current conditions and the ongoing trends in
the hi-res cams. Will continue with isolated to scattered
showers this evening basically from Moosehead to Baxter to
Houlton and points southward to the Downeast coast. There is an
area of 500-1000j/kg of SBCAPE, strong low-level lapse rates of
8-9C/km and an area of 6-6.5C/km mid level lapse rates. Lifted
indices have helped in showing a rather stable airmass across
the area with most areas falling short of the convective
temperature. Will have to watch any thunderstorms into the
evening developing ahead of a shortwave whether they hold
strength with the loss of daytime heating into our western
zones. Confidence in storms has resulted in the need to remove
all enhanced wording for this evening.

Tonight, after any showers and storms fall apart expecting
patchy to areas of fog to develop across the area especially
Downeast with the light winds. Mild temperatures tonight across
the northern 2/3rd of the CWA with lows in the upper 50s to low
60s by daybreak. Cooler lows along the Downeast coast with a
slight wind off the water with lows in the low 50s.

Tomorrow, another chance of showers and storms across portions
of the CWA. The weak dew point boundary from today will likely
be present again tomorrow lingering across the Central
Highlands. This boundary will slowly drift south tomorrow and
provide the surface lift for showers and storms to develop.
Confidence in storms is low given the uncertainty of
destabilization. This will likely be pulse convection with
temperatures warming significantly into the 80s south of the
boundary likely topping out in the upper 80s for Bangor. North
of this boundary expecting low 80s. Wind off the water will
keep the Downeast coast cooler in the 60s and 70s. Modeled
sounding showing around 500-1000j/kg of SBCAPE across the
Central Highlands into portions of Aroostook County. Mid level
lapse rates as typical will struggle to get to 6-6.5C/km with
low level lapse rates generally 8-9C/km. Once again weak shear
but EBWD modeled at 30-35kt within inverted "V" signature
soundings suggests any storm collapse could produce some gusty
winds. Confidence is too low at this point to put in enhanced
wording.
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&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Somewhat muggy, unsettled weather continues into Thursday. Best
chance of precipitation comes late Wednesday night into Thursday
morning just ahead of an approaching cold front, with PoPs 60
percent of greater for most areas. Some uncertainty with the
timing of the front, however. Could see some thunderstorm
activity Thursday afternoon, especially if the front progresses
on the slower side of model solutions which would allow the
unstable air to linger into the afternoon. Not terribly
concerned about severe storms late Thursday, but can`t totally
rule them out either. Drier air moves in Thursday night behind
the cold front with falling precipitation chances. Lower
dewpoints for Friday, but still rather warm with highs around
80. A fairly potent upper level/vort max with associated cold
front may approach from the NW late in the day, bringing some
storms mainly to the north. Some uncertainty with the amplitude
of this feature, but if the higher amplitude solution pans out,
could be a rather active afternoon for storms Friday mainly in
the north.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Cooler airmass moves in Friday night behind the cold front, and
we remain in a cooler weather pattern for the holiday weekend
into early next week with temperatures fairly close to average.
It could still be fairly unsettled for this period, but model
agreement is poor and it`s hard to hang your hat on any one
system. Some models/ensembles develop a cutoff upper low over
the region late Monday into Tuesday, and if this happens, we
could see a decent widespread rain and cool temperatures. Still
enough uncertainty in this feature, though, that went with PoPs
around 40 percent.

&&

.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: Northern Terms...Generally VFR through tomorrow.
W winds 5-10kt becoming light and variable tonight. Tomorrow
light and variable winds. -SHRA and perhaps VCTS tomorrow
especially at PQI, HUL.

Southern Terms...Generally VFR. Becoming MVFR/IFR possible
tonight with BR/FG after 06z. Winds becoming light and variable
tonight. SW winds tomorrow 5-10kt with gusts up to 15kt. VCSH
possible at BHB and -SHRA and possible VCTS at BGR tomorrow.

SHORT TERM:
Wednesday night...MVFR/IFR in patchy fog and showers late.
Light S winds.

Thursday...VFR tempo IFR in storms along a cold front in the
afternoon. Light S winds, SW 5-10kts in the afternoon.

Thursday night-Sunday...Mainly VFR with possibility of MVFR from
time to time, but low confidence on when. Potential for storms
in Northern Maine Friday afternoon. Wind SW 5-10kts becoming NW
5-15kts Saturday morning, eventually switching back to S 5-10kts
Sunday.

&&

.MARINE...
NEAR TERM: Patchy to areas of fog develops tonight reducing vsby
at times. Patchy fog tomorrow with most fog lifting and mixing
out tomorrow. Otherwise winds/waves remain below SCA. SW winds
below 20kt and seas generally 2-4ft.

SHORT TERM: Winds and seas below small craft levels through
Sunday. Patchy fog at times over the waters.

&&

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

&&

$$


Near Term...CB/Sinko
Short Term...Foisy
Long Term...Foisy
Aviation...CB/Sinko/Foisy
Marine...CB/Sinko/Foisy