772
FXUS61 KCAR 140348
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1148 PM EDT Sat Jul 13 2024

.SYNOPSIS...
An upper level disturbance will cross the region overnight.
High pressure will build across the region 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/...
Update...
An upper level disturbance will cross the region through the
early morning hours, exiting across the Maritimes late. At the
surface, a frontal boundary will slowly move offshore overnight
while surface high pressure builds toward the region.
Isolated/scattered showers will occur with the upper
disturbance through early morning. Low level moisture from
afternoon/evening rains will help support patchy fog across much
of the forecast area overnight. More extensive fog is possible
along the Downeast coast. Low temperatures will range from
around 60 to the lower 60s north, to the lower to mid 60s
Downeast. Have updated to adjust for current conditions along
with expected overnight temperatures, clouds and shower chances.

Previous Discussion...
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 /04Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: Variable conditions with any showers through early
morning. Also, variable conditions with any fog overnight into
Sunday morning. Otherwise, VFR overnight into Sunday. Variable
winds 5 to 10 knots overnight. West/southwest winds 5 to 10
knots Sunday.

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/seas below small craft advisory levels overnight
through Sunday. Isolated showers through early morning. Areas
of fog overnight into 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...Beach Hazards Statement from 8 AM EDT Sunday through Sunday
     evening for MEZ029-030.
MARINE...None.

&&

$$


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