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646
FXUS61 KCAR 040850
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
450 AM EDT Tue Jun 4 2024

.SYNOPSIS...
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Weak high pressure builds through tonight, before slowly
drifting east Wednesday and Wednesday night. A complex storm
system then slowly approaches from the west Thursday through
Saturday.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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The area remains under the influence of a blocking high through
the period. The ridge axis remains west of the forecast area as
a classic omega block takes shape later tonight. Nearly
stationary vertically stacked low pressure south of Newfoundland
will prevent much warm advection. Highs today will be just
nominally warmer than Monday for most locations. The low is
trying to advect low level moisture westward into eastern Maine
and some stratocu fields can be expected this morning, but
should lift and scatter for the afternoon given the time of
year. The clouds may be a bit more persistent for Downeast where
highs will stay in the lower 70s today. Light winds will also
promote an afternoon sea breeze towards the coast. Patchy fog is
possible along the coast later tonight. Lows tonight will drop
to the low to mid 50s.
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&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
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The pattern will remain fairly stable through Wednesday, with
Maine still mostly under the influence of the upper level low
over the Canadian maritimes. A weak shortwave moving through on
Wednesday will increase the likelihood of afternoon showers
mainly for the inland regions. The combination of some higher
CAPE values and terrain influences may generate a few
thunderstorms, mostly over the Central Highlands. Think that
terrain influences may extend the thunderstorm possibilities a
little further north, so expanded the thunderstorm chances
northward and eastward from the previous forecast. However,
overall thunderstorm coverage should remain isolated in nature.
The general shift to easterly/southeasterly flow will increase
moisture across the area, so fog is coverage is also expected to
increase for both Wednesday night and Thursday night.

On Thursday, the occlusion to the west will begin to affect the
state and a chance of showers will spread across the region.
Upper level clouds ahead of this system should limit daytime
heating, so low level lapse rates will not be as strong and
thunderstorms are not expected. Temperatures will remain
seasonable through the short term with daytime highs in the 70s
to low 80s and nighttime lows in the mid to upper 50s.
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&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
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By Friday, the pattern will shift slightly and the next upper
level low will approach from the west, while the low over the
Canadian maritimes gradually weakens and shifts eastward. The
ridge between these two systems will weaken slightly and become
more of a col over Maine. As a result, the general surface
pattern will be more unsettled as we head into the weekend. An
occluded front associated with a surface low in eastern Ontario
will approach Maine from the southwest, while the triple point
will cross southern New England. There are not a lot of dynamics
associated with this system, so although a surface low will
potentially develop along the triple point, this does not appear
to be a significant weather producer and the stronger portion
will move rapidly offshore. This leaves Maine under the
influence of the upper level low and the deteriorating
occlusion. The lack of strong upper level dynamics make this
pattern more difficult to resolve, and models are varying on
both the timing and the placement of the occlusion for the
weekend.

In terms of sensible weather, this boils down to an uncertain
but generally unsettled outlook for the weekend. Rain showers
can be expected to develop from the southwest, but the timing on
this may be as early as Friday morning or as late as Friday
evening. The best chance for thunderstorms will be in the
afternoon on Saturday and Sunday, as the upper level low shifts
eastward and brings some cooler air aloft in combination with
afternoon heating.
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&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
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NEAR TERM: MVFR tempo IFR due to cigs and vis early this
morning, then becoming VFR at all sites by mid to late morning.
Light and variable winds. Chance of IFR cigs/vis towards BHB and
BGR later tonight.

SHORT TERM:

Weds...VFR. Slight chance of MVFR in -SHRA at BGR. Light winds.

Weds night-Thurs night...Mainly VFR, except possible MVFR/IFR
overnight in fog at southern terminals. SE winds 10 kts.

Fri - Sat...Mostly VFR, possible MVFR in -SHRA in the afternoon.
Possible TS at BGR Fri afternoon/evening, and at northern
terminals Sat afternoon. E winds 10 kts.
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&&

.MARINE...
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NEAR TERM: Seas will be 1 to 2 feet or less under a high
pressure regime. Adjusted model winds downward for the
stability. The stability will generate patchy fog this morning
and again tonight. Chances for fog increase tonight as
incrementally warmer/moister air moves over the waters.

SHORT TERM: Winds will remain below 25 kts through the period.
1 to 2 foot seas will prevail through Thurs. Friday and
Saturday, southerly swell will return and seas will increase to
around 4 feet. Wednesday and Thursday, warm air moving over the
waters will increase fog coverage. On Friday, instability will
increase ahead of the incoming system and fog will become more
patchy in nature.
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&&

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

&&

$$


Near Term...MCW
Short Term...LF
Long Term...LF
Aviation...MCW/LF
Marine...MCW/LF