348
FXUS61 KCAR 201012
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
612 AM EDT Sat Jul 20 2024

.SYNOPSIS...
A cold front will approach today and cross the area tonight into
Sunday. High pressure will build over the area Monday. A frontal
system will stall over the area Tuesday into Wednesday. Weak low
pressure will track south of the region on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
6:10 AM Update...Forecast remains on track with a clear sky
across the area early this morning. Minor adjustments were made
to early morning temps to reflect the colder valleys which
dropped to near 50 degrees. Otherwise, no major changes needed.

High pressure south of the area today will bring a mostly sunny
and warm day with a light southwesterly breeze. A cold front
pushing south from a cool upper low over Quebec will approach
this afternoon and begin to push into northwestern parts of the
region late in the afternoon. Some weak instability ahead of the
front with CAPEs up to around 100 J/KG extending up to around
15-20 K ft, combined with surface convergence ahead of the
front, may bring spotty thunderstorms to far northwestern parts
of the area late this afternoon into early this evening.
Moisture thins out later this evening as the front pushes
through. Spotty showers may push south with the front across the
northern half of the area this evening but instability will
probably be too weak to support thunderstorms. The cold front
will clear the northern part of the area by dawn on Sunday as
it approaches the southern half of our region. This will allow
the sky to clear across the north behind the front late tonight
as cooler and drier air pushes in. The front will be carrying a
band of clouds and isolated showers into central and southern
parts of our area early Sunday.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
The cold front will progress through the area Sunday, bringing
cooler and less humid air. There is the risk of a brief shower
in the southern half of the forecast area, and maybe even a
couple of thunderstorms along the coast if the frontal boundary
has not exited the area by the time max heating occurs. A cool
upper trough will help with destabilization. If a thunderstorm
can form near the coast, shear looks more than adequate for a
stronger storm or two. Further inland, a deep mixed layer and
offshore flow will help propel high temps into the lower 70s
north and upper 70s to lower 80s for interior Downeast and the
Bangor area. The deep mixed layer will also produce gusty
northwest winds reaching 20 to 25 mph at times. Dew points will
be much lower than we have seen in recent weeks. Went with the
lower end of guidance with readings in the 40s behind the front
Sunday afternoon.

For Sunday night, the air mass is so cool that bias-corrected
guidance looks much too high. Expect lows in the 40s for the
northern half of the area and low to mid 50s for Bangor and
coast. Light winds and clear skies will ensure a shallow
inversion develops.

The inversion will burn off quickly Monday morning, but the air
mass remains relatively cool. Under generally sunny skies, highs
will nominally increase to the mid 70s north and lower 80s for
Bangor and Downeast. Once again, an offshore flow will bring the
warmer temps right to the coast.

Clouds will tend to increase Monday night as a cold front sags
southward from Canada in the northern stream and a warm front
pushes northward from the Mid-Atlantic region. As a result, lows
increase to the mid to upper 50s across the area. There are
indications of low clouds/fog moving towards the Hancock County coast
late night, and some elevated instability is noted advancing
northward from southern Maine and the Gulf of Maine late Monday
night. Confidence is not high enough to include mention of
thunder at this time.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
The long term forecast for next week was generally predicated on
the idea that a frontal boundary will be somewhat stationary
over the area with mostly cloudy skies, showers, high humidity
and a lower diurnal temperature range. This follows NBM
guidance.

The synoptic pattern involves a northern stream shortwave
digging into the Great Lakes region on Tuesday while deep
southern stream moisture advects northeastward from a trough in
the lower Mississippi Valley towards New England. Precipitable
water values will surge towards 1.5 to 2 inches over the area by
mid week.

At some point later in the week, an organized low with heavier
precip may form. Timing and location remains problematic with
solutions varying from the 20/00Z GFS on Wednesday night to the
20/00Z ECMWF pointing towards Friday. The difference lies in
whether the Great Lakes trough evolves into a cut-off upper low
west of the area Thursday...as advertised by ECMWF.

Did not include mention of thunderstorms in the long term due
to cloud cover and lack of consensus in guidance. That said, the
general pattern will be conducive with a little extra surface
heating and/or upper level shortwaves that are not well resolved
at this point.

Using a consensus of guidance, keep highs in the upper 70s to
lower 80s across the area next week. Wednesday stands the
greatest chance of being a bit lower due to thicker cloud cover
and a strong frontal inversion.

The exit of the upper trough by next weekend appears likely to
be followed by a strong upper ridge with another round of well
above normal temperatures and humidity.

&&

.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: VFR conditions are expected today and tonight. Winds
light SW today then very light W becoming NW tonight.

SHORT TERM:
Sunday...VFR with a slight chance of an afternoon thunderstorm
along the coast from BHB towards Eastport. NW winds 10 to 15 kt.

Sunday night and Monday...VFR with light winds.

Monday night...Chance of IFR cigs towards BHB and BGR late
night.  Otherwise VFR with light winds.

Tuesday...Chance of IFR cigs towards BHB and BGR in the morning.
Otherwise VFR with light winds. Slight chance of afternoon
thunderstorms north of BGR.  Light south winds.

Tuesday night and Wednesday...Increasing risk of IFR cigs moving
north from the coast across the area. Slight risk of embedded
thunderstorms with a warm front.

&&

.MARINE...
NEAR TERM: Wind and seas will be below SCA today and tonight. A
bit of light mist may cover the waters through tonight ahead of
the cold front.

SHORT TERM: Winds and seas remain under advisory criteria
through the period. Strong stability led to reductions in
guidance winds in the forecast through next week. Increasing
humidity next week increases the risk of fog beginning later
Monday night through later next week.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement through this evening for MEZ029-030.
MARINE...None.

&&

$$


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