116
FXUS61 KCAR 131920
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
320 PM EDT Sat Jul 13 2024

.SYNOPSIS...
An upper level trough will cross the region this evening,
followed by high pressure on Sunday. A cold front will begin to
approach Tuesday. The front stalls over the region on Wednesday
and moves out of the area Thursday.
&&

.NEAR TERM /THROUGH SUNDAY/...
The upper level trof will continue to move across the region
tonight. High res models show scattered rain showers and some
isolated thunderstorms continue into tonight, though the lose of
daytime heating will decrease thunderstorm possibility. After
midnight, the trof will exit to the NE, pulling the rest of the
showers out to the E. Once again, fog is expected tonight, but
mainly staying along coastal Downeast with the marine layer.
Temps in the 60s.

For Sunday, a weak upper level ridge will move in bringing
mostly sunny skies and hot temps. In addition, W flow will bring
lower dewpoints with the slightly cooler and dry mid level
airmass. Temps will be in the upper 80s across the region.
&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
High pressure and clear skies remain in place Sunday night, but
so will the humid air mass. Once again, lows will only drop
into the mid 60s for most of the area...a bit warmer than the
previous night.

High temperatures on Monday will again climb into the upper 80s
with lower 90s expected in southern Penobscot and southern
Piscataquis counties. No change in humidity means another day
just shy of Heat Advisory criteria for Bangor. The only
differences from Sunday will be a cooler day on the coast due to
a more onshore flow, and the possibility of afternoon
convection in the north. A weak shortwave propagating in a fast
northern stream flow would be the culprit to destabilize the
atmosphere, but there is little agreement in guidance on the
evolution and timing of this feature...possibly because it may
involve an MCS that has yet to form. Therefore, confidence
remains low and have generally only assigned 15 to 30 percent
PoPs for Monday afternoon. Any upstream MCS formation could
alter the forecast Monday night into Tuesday.

Upper level ridging starts to break down Tuesday, but not before
the most of the area experiences another day in the upper 80s to
lower 90s. It may end up as the warmest day of the week, and it
is the most likely day for any heat advisories. Our current
forecast indicates advisory criteria will be met in
south/central Penobscot and southern Piscataquis counties and
confidence is increasing. Onshore southerly winds will provide
some relief for the Downeast coast. As a vigorous upper trough
digs southward towards the Great Lakes region, a lead shortwave
and frontal system will approach the area late Tuesday with the
potential for afternoon thunderstorms. The risk will be greatest
in the northern zones. Deep layer shear will increase during
the afternoon and the potential for strong storms is there.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
There are signs of a temporary break in the heat later next week
as a fairly strong upper trough digs southward from Canada
towards the northeastern US. However, the price for the cool off
will be continued heat early next week and the potential for
strong thunderstorms Tuesday and Wednesday.

A cold front tends to hang up over the area Tuesday night into
Wednesday as the upper trough continues to dig southward into
the Great Lakes region. The stalled front seems likely to become
a conduit for strong thunderstorms on Wednesday afternoon.
Impressive deep layer shear and steep low level lapse rates are
two factors that prompt concerns for even more severe potential
than Tuesday. The question will be which part of the forecast
area is most vulnerable. At this point, the southern half of the
CWA appears to have the best instability to go with the potent
shear. This is the same area that will experience another day
with heat indices in excess of 90F.

The front is expected to sweep across the area later Wednesday
with a markedly cooler air mass.  Dew points back in more
comfortable 50s seem likely. High temps will trend back towards
seasonable readings for Thursday into Saturday.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
NEAR TERM: VFR conditions tonight for all terminals, except BHB
where conditions will drop after sunset to MVFR/IFR in cigs/vsby
due to low stratus and patchy fog. By Saturday, VFR for all
terminals. Light W winds.


SHORT TERM:
Sunday night...Chance of IFR to LIFR vis in fog for BHB and
coastal sites.

Monday...Generally VFR. Slight chance of afternoon
thunderstorms, mostly west of a GNR to HUL line.  Light winds.

Monday night...Chance of IFR to LIFR vis in fog for BHB and
coastal sites. Otherwise, VFR with light winds.

Tuesday...VFR outside of scattered afternoon thunderstorms,
mostly north of GNR and HUL.  Light winds.

Tuesday night...Chance of IFR to LIFR vis in fog for BHB and
coastal sites. Otherwise, VFR with light winds.

Wednesday...Strong thunderstorms are possible.
&&

.MARINE...
NEAR TERM: Winds and seas will remain below SCA levels tonight
and Sunday.

SHORT TERM:
Fog will be the primary concern until a strong cold front moves
through late Wednesday. Thunderstorms will become a slight
concern Tuesday evening, and a bigger concern later Wednesday
with a strong cold front moving across the waters. Continued to
adjust guidance winds and seas downward due to strong low level
stability.

&&

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

&&

$$


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