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000
FXUS61 KCAR 260327
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1127 PM EDT Sun Jul 25 2021

.SYNOPSIS...
A warm front will lift across the area tonight. A cold front
will cross the area on Tuesday. High pressure will build over
the area Wednesday. Low pressure will approach on Thursday.

&&

.NEAR TERM /THROUGH MONDAY/...
11:30 PM Update...A line of showers and embedded thunderstorms
can be seen moving toward the northwestern part of our area from
the west. Increased pops and put isolated thunderstorms in as
this moves through. However, anticipate it may weaken overnight
as it moves across. Otherwise, no major changes this hour.

Prev Disc: The warm front and transition to a more humid air
mass is the dominant feature tonight into Monday morning with
fog developing across the entire area tonight. A Dense Fog
Advisory may be needed but will hold off for now. Rain will
taper off by early evening ahead of the warm front, but light
rain and drizzle is certainly possible throughout the night.
Later tonight, an upper level shortwave will cross the area.
This shortwave is currently associated with thunderstorm
activity in southern Ontario and western Quebec. Although not
all guidance shows it holding together across the northern half
of the forecast area later tonight, some CAMS output has shown
it for days and continues to do so. There`s some decent cooling
aloft while a low level thermal ridge builds at the top of the
frontal inversion tonight. This generates some elevated CAPE
later tonight and shear also increases. Will maintain mention of
isolated thunderstorms across Aroostook County late tonight
into early Monday morning. Low clouds and fog will slowly burn
off Monday morning. By this time the occluded front has moved
across the area, leaving a much warmer and humid air mass. The
morning low clouds will slow production of SBCAPE, but
eventually there should be sufficient instability for isolated
to scattered afternoon thunderstorms. The best CAPE and shear
will be in southern Penobscot County and interior Downeast for a
brief time in the early to mid afternoon. Shear looks marginal
for strong storms. There`s also the remnants of the washed out
occluded front in that area. There`s several factors inhibiting
convection such as very dry air aloft, lack of a decent upper
level shortwave like earlier in the day, and a cap near 500mb.
Will mention thunderstorms across the area in the afternoon, but
hold off on enhanced wording.

Smoke is the other emerging issue for Monday. Have not added
smoke or haze in the gridded forecast database at this time, but
HRRR guidance and METSAT imagery shows smoke from Manitoba and
Ontario fires heading this way...and it may mix towards the
surface by Monday morning. That usually generates a lot of
confusion and concern from the public. By the time clearing
occurs later Monday morning into the afternoon, the smoke will
likely be more noticeable.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
Area wl be split btwn two fronts on Mon evening. Cannot rule out
lingering showers over srn and nrn areas with an isold tstm
still possible but coverage wl likely be on the decrease with
loss of diurnal htg. Given moist and humid airmass still in
place wl likely see areas of fog acrs the area Mon night.

Depending on how quickly high pressure builds south out of
Canada Tue morning wl determine where storms wl develop in the
aftn as s/wv heads south and east out of Canada. This wl allow
storms to develop along front dropping thru the CWA and shud
allow storms to develop across central and srn zones aft 18z.
Given the uncertainty have hesitated to call it chc showers and
tstms and hv only worded it as isold tstms until details can be
better ironed out.

Secondary front wl mv offshore Tue evening with showers winding
down aft midnight along the coast. Patchy fog expected to
develop acrs the north as skies clear but drier dwpts may
prevent fog to increase in coverage drg the overnight. Downeast
coast may see patchy fog as well as humid airmass rmns in place,
however skies wl still be cldy and prevent more widespread
coverage.

Sfc high pressure wl be building into nrn New England with cool
northerly flow draining out of Canada. Skies will be mocldy on
Sunday with nw winds ocnly gusting drg the afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Flow rmns out of the nw aloft thru Wed night and wl gradually
transition to a s/wv ridge acrs Maine Thu morning. Sfc high
pressure wl be building well offshore Wed night and with skies
clearing and light winds cannot rule out areas acrs the
northwest dipping into the mid-40s.

Next system wl be heading in fm the west and guidance fairly
consistent in bringing showers, possibly stratiform rain, in wrn
areas on Thu afternoon. Rain continues Thu night with showers
expected especially across the north on Friday as upr lvl trof
mvs thru Quebec into the Maritimes. Temps likely to be below
normal thru the end of the long term and into next weekend.

&&

.AVIATION /04Z MONDAY THROUGH FRIDAY/...
NEAR TERM: Conditions to continue to deteriorate this evening to
IFR and then LIFR due to low cigs, drizzle and fog. Fog is most
likely for GNR towards HUL and points south...especially on the
coast. FVE will also have fog. LLWS is expected late this
afternoon into the early evening. Thunderstorms are possible
north of HUL and GNR after midnight into early Monday morning.
Isolated afternoon thunderstorms are expected Monday afternoon
after morning fog and low clouds dissipate.

SHORT TERM: Mon night...Potential IFR in areas of fog
developing late at all terminals. Light WSW wind.

Tue...Becoming VFR late morning with localized MVFR restrictions
in -tsra, mainly at HUL and BGR. W 5-10kts.

Tue night...VFR early, decreasing to localize IFR in fog late.
NW 5 kts.

Wed-Wed night. VFR. NW 5-10kts Wed becoming light SW Thu
morning.

Thu-Fri...Lowering to MVFR/IFR in rain and fog. S 5-10kts,
becoming SW Fri morning.

&&

.MARINE...
NEAR TERM: Fog will thicken and become more widespread tonight
and slowly move offshore Monday afternoon...returning again in
the evening. S Wind Gusts will reach as high as 20 kts ovrngt
before subsiding by daybreak, but will fall short of advisory
criteria. These south winds will generate south seas reaching up
to 4 feet by late tonight, then subsiding durg the day Mon.

SHORT TERM: Winds and seas to remain below SCA thresholds
through the week. Expect that humid airmass will bring areas of
fog to the waters Mon night and Tue night before a cold front
crosses the waters Wed morning.

&&

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

&&

$$

Near Term...VJN/MCB
Short Term...Farrar
Long Term...Farrar
Aviation...VJN/Farrar
Marine...VJN/Farrar