969
FXUS61 KCAR 200359
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1159 PM EDT Sun May 19 2024

.SYNOPSIS...
High pressure will ridge across the region through early week,
then build south of the area through the middle of the week. A
strong cold front will cross the area Thursday, followed by high
pressure Friday into next weekend.

&&

.NEAR TERM /THROUGH MONDAY/...
Update...
High pressure will remain across the region overnight. Just
minor adjustments to hourly temperatures and dew points
otherwise no other changes. Lows tonight are expected to fall
to around 50 degrees in most areas.

Previous Discussion:
By Monday, as the axis of the upper level ridge begins to shift
south, a weak surface trof develops. For the morning, RH models
show the skies starting to clear with fair weather cumulus
sticking around into the afternoon. Upper air model soundings
show the instability increasing across the north with the higher
values in the North Woods. CAPE values greater than 1000 J/kg,
lapse rates greater than 7, and increasing upper level
divergence are all good indicators for isolated thunderstorms in
the afternoon and into the evening. Bulk shear is lower than
general severe criteria, so the possibility of stronger storms
is low, but cannot rule it out. Temps in the upper 70s in the
north and low 70s in the south with coolers temps at the coast.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
In general, a powerful upper ridge will dominate area weather
through the period with subsidence and warming. The warmest
temperatures of the year can be expected during the period with
highs reaching the 80s and lows over 60F for large portions of
the forecast area by Tuesday night.

A series of fronts riding the northern periphery of the ridge
through the period represents the forecast challenge in terms of
thunderstorms and exact hi/low temperatures through the period.

On Monday night, expect a weak northern stream cold front to sag
southward into the area accompanied by an equally weak upper
shortwave. The net result is expected to be an isolated evening
thunderstorm in northern Aroostook County and no cold air
advection. Lows in the northern half of the forecast area will
be in the mid to upper 50s while an onshore flow of cool marine
air will drop coastal lows towards 50F with the threat of fog.
The front will likely stall over the area for Tuesday.

The big question for Tuesday will be the progression of today`s
convective disturbance over Kansas over the upper ridge and
towards northern Maine. Guidance is offering a wide variety of
timing solutions from Tuesday to Tuesday night, possibly as an
MCS. The former timing favors the risk of a fairly significant
convective outbreak featuring robust shear and some of the
unpleasant outcomes that can bring in late May. The latter
solution brings the hottest day of the year to date on Tuesday
without thunderstorms until Tuesday night, if any.

Onshore winds will ensure cooler temps and stability towards the
coast on Tuesday.

The frontal boundary location remains the nexus between
temperature and PoP forecasts into Wednesday. At this point,
have played for slightly cooler highs in northern zones due to
the boundary, but mid 80s or higher seems likely for the Bangor
area. If the frontal boundary moves northward more rapidly,
these mid 80s may extend northward across the entire forecast
area. In terms of convection, expect the upper level ridge to
build on Wednesday and cap convection. Did mention a slight
chance of afternoon thunderstorms in case the cap breaks or
there is a large timing error regarding the disturbance expected
Tuesday and Tuesday night.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Thunderstorms are again a threat for Wednesday night as a
weakening warm occlusion moves through the area. Clouds, precip
and warm advection will keep lows in the 60s and humidity will
reach its zenith so far this year with dew points in the lower
to mid 60s.

These dew points will continue ahead of a strong cold front on
Thursday. The cold front will act a potent trigger for
widespread convection. All of the ingredients for an active day
seem to be in place: CAPE, strong shear and anomalous PWs. About
the only issues to lessen severe potential will be unfavorable
timing for the frontal passage or unexpected development of a
strong/persistent low level inversion. It has been quite a few
years since we have seen such a favorable setup for severe
weather in late May. The hydro aspect will also have to be
watched given the deep moisture.

The front will exit quite quickly Thursday night and bring a
very welcome relief in terms of temperatures and dew points for
Friday and throughout next weekend. There will still be the
chance of light rainshowers with the upper trough on Friday, but
expect the threat of thunderstorms to be over. Highs return to
the 60s for the holiday weekend with lows in the 40s.

&&

.AVIATION /04Z MONDAY THROUGH FRIDAY/...
NEAR TERM: VFR conditions expected at the Aroostook terminals
overnight. VFR at KBGR/KBHB gives way to MVFR/IFR alter tonight
in patchy fog and low clouds. Light S wind tonight.

Conditions will begin to improve beyond sunrise Monday morning,
increasing towards VFR cigs by early Monday afternoon once
more. Winds light and variable overnight becoming S to SW at 5
to 10 kts through the day on Monday.

SHORT TERM: Monday night...VFR except a slight chance of evening
thunder near FVE and slight chance of fog at BHB. Light south
winds.

Tuesday...VFR with a chance of thunderstorms...mostly in the
afternoon north of BGR. Light south winds.

Tuesday night...VFR except a slight chance of fog at BHB. Light
south winds.

Wednesday...VFR with a slight chance of afternoon thunderstorms.
Light south winds.

Wednesday night...VFR with a slight chance of fog at BHB. Light
south winds.

Thursday...VFR tempo IFR in strong thunderstorms. Light south
winds outside of thunderstorms.

Thursday night into Friday...VFR with tempo MVFR cigs possible
north of HUL early Friday. Scattered showers possible north of
HUL.

&&

.MARINE...
NEAR TERM: Winds and seas will remain below SCA conditions
tonight and Monday. Patchy fog is expected over the waters
tonight.


SHORT TERM: Warm and relatively humid air moving over the cold
waters is likely to cause fog at times Monday night into
Thursday night. The stability will reduce winds and seas through
next week. In general, southwest winds around 10 to 15 kt can be
expected until Friday night when winds will become more
westerly. Seas will mostly run 2 to 4 feet, but south swell may
exceed 5 feet on Thursday and necessitate an SCA.

&&

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

&&

$$


Near Term...TWD/LaFlash
Short Term...MCW
Long Term...MCW
Aviation...TWD/LaFlash/MCW
Marine...TWD/LaFlash/MCW