139
FXUS61 KCAR 270320
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1120 PM EDT Thu Sep 26 2024

.SYNOPSIS...
Low pressure will cross the area tonight, then exit across the
Maritimes Friday. High pressure will build down from the north
this weekend and remain over the area through early next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
11:20 PM Update...Showers remain across the area, mostly over
eastern parts of the region with only a few spotty light showers
over the west. Precipitation coverage looks good on this
forecast. Raised temperatures a couple degrees over the south
early in the overnight period. Otherwise, forecast looks good.

Previous Discussion...
Surface low pressure will begin to cross the forecast area
later tonight with an occluded front. Aloft, the supporting
upper low reaches northern Maine overnight. Rain will persist
across the forecast area early tonight. The better moisture will
then begin to exit across the Maritimes later tonight, allowing
the steadier rain to taper to showers. The most extensive
showers overnight will occur across northern areas in the
vicinity of the upper low. The surface/upper systems exit across
the Maritimes Friday. However, a disturbance moving around the
exiting upper low will cross the forecast area. The upper
disturbance will help support the risk of showers across the
forecast area Friday, most extensive across northern and eastern
areas. Otherwise, moisture wrapping around the exiting system
will keep mostly cloudy skies across much of the forecast area
Friday, with partly sunny/mostly cloudy skies across southwest
areas. Low temperatures tonight will range from around 50 to the
lower 50s north, to the lower 50s Downeast. High temperatures
Friday will range from around 60 to the lower 60s north, to the
mid to upper 60s Downeast.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
Low pressure will continue to exit to the southeast Friday night
through Saturday, with high pressure building over the forecast
area in its place. With this change in air mass will come a
return of drier air in the upper levels, limiting shower
chances. That said, an inverted trough behind the departing low
may still lead to isolated rain showers Saturday afternoon,
which coincide with peak diurnal heating. Any showers which do
develop will likely remain confined to the north.

Patchy fog may form early each morning as low level moisture
lingers, and is particularly likely in any areas which see
rainfall the day before, increasing the low level moisture prior
to nocturnal surface decoupling. As high pressure builds in and
skies begin to clear late Saturday night, surface decoupling may
allow for temperatures to fall into the mid 40s across the north
and upper 40s Downeast. Fog development should help limit
temperatures from falling much further, but if fog fails to
form, lows could make a run for the upper 30s early Sunday
morning. Temperatures may lift back into the upper 60s to around
70 during the day on Sunday as skies continue to clear.

&&9:39 PM Update...Last of the steady rain is over the Downeast
Coast at this time, especially over Coastal Washington County.
This rain will gradually move offshore over the next few hours.
Across the North, scattered to numerous showers will continue
through the night with the approaching upper level low. Some
patchy fog has developed in a few places. Will continue to
monitor the potential for fog development as the night
progresses. Made minor tweaks to temperatures, PoPs, winds, and
sky cover to match latest trends.

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A ridge of high pressure will remain over the forecast area
through early next week. This subsidence pattern could lead to
mostly clear skies and subsequent surface decoupling which may
allow for temperatures to plummet overnight. The most likely
coldest night through the extended forecast period is Monday
night, with cold air advection through the day on Monday
followed by mostly clear skies and light winds Monday night. If
river valley fog does not develop under these conditions, then
there could be the chance for frost development, particularly
across more sheltered valleys in the north which tend to run
colder.

For later Wednesday into the day on Thursday, another front
could approach from the west, bringing another chance for rain
showers into the forecast area. Recent model trends suggest the
high pressure from earlier in the week may be strong enough to
hold off the front, such that the front weakens as it pushes
into the area, and rain may not be widespread across the are9:39 PM Update...Last of the steady rain is over the Downeast
Coast at this time, especially over Coastal Washington County.
This rain will gradually move offshore over the next few hours.
Across the North, scattered to numerous showers will continue
through the night with the approaching upper level low. Some
patchy fog has developed in a few places. Will continue to
monitor the potential for fog development as the night
progresses. Made minor tweaks to temperatures, PoPs, winds, and
sky cover to match latest trends.a. At the same time, the
remnants from Helene will be pushed off the coast by this front.
The blocking high pressure should be enough to keep this
rainfall south of the area, but if the high trends weaker, some
of this moisture could enhance rainfall into the Downeast
region.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: Mainly IFR/LIFR tonight with RA tapering to -SHRA and
BCFG. Across northern areas Friday, IFR early slowly trending to MVFR
with -SHRA and low clouds. Across Downeast areas Friday,
IFR/MVFR early with BCFG, then VFR during the PM. Isolated to
scattered showers in the PM. S-SE winds around 10 knots this
evening, becoming S-SW late tonight. Variable winds 5 to 10
knots Friday, becoming N-NW.

SHORT TERM:
Fri night: Conditions improving to VFR across all terminals.
Brief IFR possible late in patchy fog. N wind around 5 kts.

Sat: Mostly VFR. Brief -SHRA possible across northern terminals.
N wind. Winds light and variable.

Sat night...VFR conditions across all terminals, though brief
IFR vis possible in patchy fog at any terminals which see rain
on Sat. Winds light and variable.

Sun - Tues: VFR across all terminals. Winds NW around 5 kts,
shifting SE by Tues 5 to 10 kts.

&&

.MARINE...
NEAR TERM: Winds/seas below small craft advisory levels tonight
through Friday. Seas could approach borderline SCA criteria this
evening on the southwestern outer waters, but not widespread
enough to issue an SCA at this time. Rain early tonight,
tapering to showers late. Patchy fog tonight into Friday
morning.

SHORT TERM: Winds and seas will likely remain below SCA criteria
through the end of the week and into the weekend. Fog could
limit visibility Friday night through Sunday.

&&

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

&&

$$


Near Term...Bloomer/Clark/Norcross
Short Term...AStrauser
Long Term...AStrauser
Aviation...Bloomer/Clark/Norcross/AStrauser
Marine...Bloomer/Clark/Norcross/AStrauser