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007
FXUS61 KCAR 140115
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
915 PM EDT Thu Jun 13 2024

.SYNOPSIS...
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High pressure will build south of the region overnight. A cold
front will cross the area Friday followed by high pressure
Saturday into Sunday. High pressure will shift south of the area
on Monday. The area will remain under the influence of high
pressure through later next week.
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&&

.NEAR TERM /THROUGH FRIDAY/...
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9:15 PM Update: Area radars show weak returns moving across
eastern Aroostook County. Mainly just mid level clouds and
likely not more than a few drops of rain reaching the ground.
More numerous showers and thunderstorms in southeast Ontario and
into southern Quebec that will head toward western and northern
sections of the FA overnight. The thunderstorm activity is
expected to weaken significantly, but clouds and scattered
showers will likely move in late tonight and into at least early
to mid morning Friday. Patchy lower clouds along parts of the
Washington County coast that may expand a bit north overnight.

Previous discussion:
A low pressure system across the north will approach the region
tonight and move through on Friday. For tonight, clouds will
gradually increase with the frontal approach. This with the
southerly flow will keep temps in the 60s across the region,
except for coastal Downeast where onshore flow will bring temps
into the 50s. RH models indicate the marine layer moving into
coastal Downeast, mainly Washington county with the onshore with
the SW winds later in the night.

By Friday, the prefrontal boundary will begin to move into the
western border of the North Woods. These rain showers will
quickly push from NW to SE through the morning. High-res models
are in much better agreement with the timing of the front and
the rain showers. By the afternoon, increased daytime heating
with the movement of the frontal boundary will increase
instability along the boundary. The 12Z NAM showed a drastic
increase in CAPE from the previous forecast. The inconsistencies
lie with the ensembles on the amount and location of the highest
CAPE. In addition, the models show a thin ribbon of highest CAPE
of +1000 J/kg stretching from Presque Isle to Greenville. Due to
this, the dependency on stronger thunderstorms will be with the
high wind shear and steep lapse rates along the boundary.
Another concern will be later in the afternoon towards the
evening when the front becomes slightly stationary over Downeast
where localized heavy rain could become an urban and small
stream flooding issue. The question will be how far north the
marine layer will reach in the afternoon to help stabilize the
area.
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&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
The cold front will move very slowly southward on Friday night
into Saturday morning as the upper trough amplifies and the RRQ
of a powerful upper jet moves through the area. Deep moisture
will advect northeastward from convective activity upstream.
Elevated convective activity will likely persist through much of
the night along the front. PWs will remain near 1.5 inches
through the night near the coast with the boundary. The tropical
disturbance moving up the eastern seaboard will be in the
process of phasing with the northern stream upper trough, but is
expected to develop far to the east of the forecast area.
Nonetheless, southern portions of the forecast area remain in
the WPC ERO through Saturday morning.

Fog is also expected along the frontal boundary for Downeast on
Friday night.

The slow movement of the front out of the area has kept showers
in the forecast for Downeast Saturday morning and clouds
lingering in Washington County most of Saturday. Cold air
advection will produce the coolest day for the foreseeable
future with highs in the upper 60s to lower 70s. Dew points will
plummet into the 30s to lower 40s by Saturday evening. This cool
and dry air raises the specter of frost in the North Woods
Saturday night under clear skies and light winds. Temperatures
will recover into the low to mid 70s on Sunday with plentiful
sunshine. North winds will prevent the sea breeze until later in
the afternoon.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Heat wave likely Tuesday into Thursday

The entire period until perhaps Thursday afternoon will be
dominated by an anomalously powerful dome of upper level high
pressure. H5 heights may reach near 600dm by Wednesday.
Temperatures warm steadily from Monday into Wednesday and
Thursday. Inland areas may see over 90F Tuesday through
Thursday, meeting the definition of a heat wave.

Dew points will become uncomfortable by Tuesday...reaching the
mid 60s to around 70F and remaining elevated into Thursday
night. This means that heat indices will reach over 100F inland
for Wednesday and Thursday. Heat advisories seem likely for
Wednesday and Thursday. The coast will enjoy the coolest temps
by far with a sea breeze, but temperatures will still be well
into the 80s by Thursday as southwest winds offer less relief.

The last heat wave of this magnitude was in June 2020 when the
all-time record high temperature at Caribou was tied at 96F.
If the forecast does not change, it will probably be one of the
most notable heat waves so far this century. The current
forecast does not feature record highs on any day for Bangor and
Caribou, but the Thursday forecast high temp of 95F at Bangor
would tie a record.

Record high low temperatures may be a better bet Tuesday night
through Thursday night.

A weak northern stream front may trigger thunderstorms in the
north by Thursday afternoon, but better odds for a cold front
and cooler temps will not occur until Friday.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: VFR for most of tonight, but with MVFR ceilings
possible very late night/early Friday morning at the Aroostook
County terminals, especially from KPQI north to KFVE, but
forecast confidence is below average. Otherwise, predominately
VFR Friday, but lower conditions possible in any showers and
thunderstorms. S/SW wind 5 to 10 knots tonight, and 10 to 15
knots and gusty Friday. Strong and erratic wind gusts in/near
thunderstorms Friday. LLWS late tonight and early Friday morning
from KBGR north.

SHORT TERM:
Friday night...VFR except IFR tempo LIFR cigs/vis for BHB and
coastal sites. Northwest winds 5 to 10 kt.

Saturday...Becoming VFR on the coast in the morning. VFR
elsewhere. Northwest winds 10 to 15 kt.

Saturday night through Tuesday...VFR with light winds.

&&

.MARINE...
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NEAR TERM: A Small Craft Advisory for outer waters begins at 5
AM EDT Friday morning and continues through Friday due to gusty
winds and seas around 5 ft.

SHORT TERM: The Small Craft Advisory remains in place Friday
evening, but skeptical of winds or seas meeting criteria.
Confidence is higher in a lot of fog Friday night into early
Saturday. Once the fog is swept out by the cold front, little
significant weather is expected until fog returns by next
Wednesday. Southwest winds on Friday night will shift to
northerly for Saturday into early Sunday. Southwesterly winds
are expected by Sunday night into Thursday.
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&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory from 5 AM to 11 PM EDT Friday for ANZ050-
     051.

&&

$$


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