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000
FXUS61 KCAR 131530
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1130 AM EDT Sat Apr 13 2024

.SYNOPSIS...
Cold front crosses the area later today as an upper level
disturbance pivots northeast. The low will dissipate to our
north on Sunday. High pressure builds in early next week and
remains over the area into midweek.

&&

.NEAR TERM /THROUGH TONIGHT/...
1125 am update...Instability parameters have increased with 12Z
analysis and guidance. The best instability occurs this
afternoon in eastern Aroostook County. The situation seems more
appropriate for early May than early April. Over 500 J/kg of
MUCAPE looks possible in eastern Aroostook this afternoon with
fairly decent shear values, a strong upper trough and an
approaching cold front. Eastern Aroostook is also where the best
surface heating is occurring today. 925mb temps remain above
10C while strong cooling will be occur this afternoon from H7 to
H5, producing nearly 7C mid-lvl lapse rates. The low -20C
threshold makes thunderstorms a distinct possibility while the
low freezing level makes graupel a likely bet with any decent
convective activity. Have extended the area with mention of
isolated thunder and small hail/graupel to include northern
Washington County as well as northern/central Penobscot and NW
Aroostook. While overall QPF values are not significant or are
PW values, convective activity would certainly be capable of
locally heavy downpours

Previous Discussion...
Sharp 500mb trof will slide overhead during the day today with
a rapidly cooling pocket of air aloft. At the surface a trough
will pivot northeast under the shortwave which will help
generate scattered to numerous showers into the afternoon.
Expecting a mostly cloudy day but a few sunny breaks are
possible which will aid in the destabilization of the
atmosphere. High temperatures will top out in the low 50s across
the Downeast coast with the wind off the Gulf of Maine. Across
the Highlands including Bangor to Moosehead expecting low to mid
50s. Across the north will be the warmest with upper 50s and
even a few 60F readings possible at Caribou, Presque Isle and
Houlton.

Speaking of destabilization...Cold air aloft over warmer
surface temperatures is a recipe for numerous showers to develop
so expecting the most showers across the Central Highlands into
Northern Maine. There will be a 3-6hr period this afternoon
into the early evening where a warm moist airmass will be
beneath the cold pocket moving overhead especially in
northeastern zones. This as seen in modeled soundings this
morning shows a period for 200-400j/kg of SBCAPE and MUCAPE to
be present especially in northeast Aroostook County. At the
same time low-level lapse rates will be steep on the order of
7.5-8C/km with relatively moist low to mid level RHs. All this
combined with modeled convective temperatures 58-60F suggest
convective showers are likely. Given a relatively lowering
freezing level and inverted "V" signature to the soundings
expecting the potential for perhaps some graupel in these
showers. Cannot rule out small hail however the best likelihood
is graupel. This will be a possibility across much of the
Northern 1/3rd of the CWA. At the same time cannot rule out a
few lightning strikes as well so will paint Isolated
Thunderstorms across Northeastern Aroostook where the best
instability develops this afternoon.

Tonight, the shortwave going negative begins to consolidate and
develops a surface low heading into the Maritimes. As the low
develops overhead cannot rule out some gusty winds before they
shift westerly behind the departing surface trof. Expecting
showers to slowly diminish through the evening into the
overnight tonight. Breezy westerly winds are expected to remain
below 20mph. Temperatures will fall back into the low to mid 30s
across the North Woods & Moosehead Region with upper 30s
elsewhere from Eastern Aroostook to the Downeast coast including
Bangor.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
An upper level long wave trough will continue to sit across the
northeast CONUS, keeping a fairly unsettled pattern into the
early work week. On Sunday, a weak shortwave will approach out
of the Great Lakes region, bringing another round of rain to the
area Sunday night into early Monday morning. Guidance is in
fairly good agreement that the center of this open wave will
pass through the Downeast region, with most precip falling
across the southern half of our forecast area.

For Monday afternoon, though the bulk of the shortwave will have
exited out into the Canadian Maritimes, the 500 mb trough
combined with the recent increase in low level moisture will
provide the ingredients needed for diurnal convection. There is
high (85%) confidence in at least a cumulus field, though with
enough moisture in place, scattered showers are possible (20%
chance).

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The unsettled pattern continues through the end of the week,
after a brief period of high pressure Tuesday night into
Wednesday. Mostly clear skies on Wednesday will lead to
temperatures reaching into the mid 50s across much of the
forecast area, and potentially reaching 60 across the Bangor
area.

A more robust low pressure system will approach from the west on
Wednesday, and begin pushing through the area Wednesday night
through the day on Thursday. The precip from this system is
likely to be rain. There is still model discrepancy as to storm
track, as well as interaction with the narrow ridge of high
pressure, which could cause a triple point low to weaken or
dodge south of our area. What all these solutions do have in
common is an occluded front swinging in from Quebec, which is
another potential source for rain through the end of the week.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: MVFR/IFR this AM with low cigs and BR becoming
MVFR/VFR today. VCSH or some -SHRA today. VCTS possible but
confidence is low to put in TAFs for PQI, CAR & FVE this
afternoon. S winds 10-15kt with gusts up to 30kt possible.
Tonight, VFR south, MVFR north with W winds 5-15kt with gusts up
to 20kt possible. -SHRA early.

SHORT TERM:

Sun - Sun night: Improving to VFR across all terminals. -SHRA
possible late, with cigs dropping to MVFR/IFR Sun night in any
rain. W winds 5 to 10 kts gusting to 20 kts, shifting southerly
and becoming light Sun night.

Mon - Mon night: Improving to VFR across all terminals.
Lingering -SHRA possible across northern terminals. W winds 5
to 10 kts gusting to 20 kts.

Tues: VFR across all terminals, though brief MVFR/IFR possible
over northern terminals in -SHRA. W winds 10 to 15 kts gusting
20 to 25 kts.

Tues night - Wed: VFR across all terminals with cigs trending
towards SKC. NW winds 5 to 10 kts.

&&

.MARINE...
NEAR TERM: Small Craft Advisory extended through the entire near
term. S winds today gusting 25-30kt across the waters. Long
period southerly swells (11 sec) slowly subsiding but remain
6-10ft across the waters. Winds shift westerly this evening and
remain gusty 20-25kt. Seas continue to subside. Southerly long
period swells (10-11 sec) generally 5-9ft through the night.

SHORT TERM: A small craft advisory continues through the day on
Sunday into Sunday evening for wave heights which will remain
around 5 to 8 ft, falling to 3 to 5 ft Sunday night into Monday
morning. Conditions are expected to remain below SCA levels
through the middle of next week.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 8 PM EDT Sunday for ANZ050>052.

&&

$$


Near Term...MCW/Sinko
Short Term...AStrauser
Long Term...AStrauser
Aviation...MCW/Sinko/AStrauser
Marine...MCW/Sinko/AStrauser