-- Discussion containing changed information from previous version are highlighted. --
034
FXUS61 KCAR 231748
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
148 PM EDT Sun Jun 23 2024

.SYNOPSIS...
Low pressure will approach today lifting a warm front north
across the region. The low will cross the area tonight into
Monday followed by high pressure on Tuesday. A cold front will
approach on Wednesday and cross the area Wednesday night. High
pressure will build in from the west on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
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145 pm update...
Steady heavy rain remains over northern areas early this
afternoon along H8 warm front. Surface warm front remains back
over New England with storm developing along the pre-frontal
trough in Upstate NY. Tornado Watch has been issued for a good
chunk of New England, along with far western Maine. Airmass over
our area remains fairly stable with warm advection aloft helping
to keep any convection rooted in the boundary layer. This likely
to be our saving grace as any surface-based storms moving in
from the west will become elevated with time late afternoon into
the evening. This does not mean that storms will fall apart once
they get toward western zones but will tend to weaken with time.
Cannot rule out lightning strikes, as plenty of instability
will be present aloft, but as far as the threat for a strong to
severe storm surviving into the Bangor Region looks pretty low
at this time. However pw values will continue to run above the
90th percentile and with very efficient rain occurring this
evening, expect that locally heavy rainfall remains the main
threat with this convection this afternoon and this evening. No
major chgs with this update.

Prev discussion blo...
Low pressure approaching from the west today will pull abundant
moisture north over a warm frontal boundary pushing north
across the area. The very moist air with precipitable water
approaching 2 inches will lift over the front producing an
expanding area of moderate to heavy rain initially over west
central areas this morning, then expanding north through midday.
Strong thunderstorms are likely in western New England. Some of
these storms may weaken and stray into southwestern parts of
our region late this afternoon but at that point the instability
will be elevated and they will likely not be a severe as the
storms to the west.

Surface low pressure will push east into the Maritimes tonight.
However, the frontal boundary will hang back across our region
with the upper low still to our west in the Eastern Great
Lakes. Some rain and drizzle will continue, mostly north, this
evening and isolated embedded thunderstorms will be possible.
Showers will diminish later tonight. Otherwise, tonight will
remain mostly cloudy with some fog and scattered showers as a
dry intrusion pushes into the area in the upper levels.

Total rainfall estimates range from around 1 inch over southern
areas to an inch and a half across the north. Locally heavier
amounts are possible in any convective bands.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
The center of the low responsible for the plentiful rain in the
near term will slowly move across southern Maine and into the
Downeast region through the day on Monday. With the slow low
progression, the chance for rain showers will continue through
the day on Monday across the majority of the forecast area. As
the low moves across the Penobscot Bay area, northeast flow
around the north side of the low will lead to upslope flow into
the Longfellow mountains. This orographic lift will act to
enhance any rain showers late Monday afternoon into Monday
evening, and bring one final round of moderate to locally heavy
rainfall. With an established stable boundary layer behind the
Sunday night rain, instability will be limited during the day on
Monday. CAPE values should be low, likely remaining below 500
J/kg at best. Mid level lapse rates could be marginal around 6
to 7 C/km, but with so little to work with, thunderstorms will
be isolated at best.

High pressure will begin to build into the area later Monday
night into the day on Tuesday, with rain chances diminishing
from NW to SE, clearing Washington county late in the day on
Tuesday. A narrow ridge of high pressure will set up over the
area, briefly clearing skies Tuesday afternoon before clouds
move in again from the west ahead of the next system.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
The next low pressure system will approach from the west on
Wednesday. During the day on Wednesday, the state will be in the
right exit region of the approaching jet streak aloft, and the
jet streak at this time may only be around 100 to 110 kts. The
subsidence out ahead of this synoptic feature will limit the
threat for diurnally driven convection Wednesday afternoon,
despite guidance suggesting an increase in 500 mb vorticity.

A cold front will begin pushing across the forecast area
Wednesday evening through Wednesday night. Current consensus
among guidance suggests that the front will slow as it makes its
way through northern New England, allowing for a center of low
pressure to ride up along the stalling front, crossing our CWA
early Thursday morning. This setup could lead to another round
of increased rainfall across the center of the forecast area.
Additionally, though still in the day 4 to day 5 timeframe,
there is some signal of greater CAPE and shear associated with
this mesoscale setup. This in turn could drive nocturnal
thunderstorms and nocturnal locally heavy rain. With this
particular synoptic and mesoscale setup, being overnight will
not greatly inhibit the threat for storms, though if these
features slow down and the same setup happens 12 hours later on
Thursday afternoon, there could be an increased risk for severe
weather.

High pressure will return through the end of the week, with
temperatures remaining around average for this time of the year
behind recent rain and cold front passage.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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NEAR TERM: IFR over all terminals tonight with LIFR possible
over Downeast terminals and possibly FVE. Thunderstorms will be
possible at HUL, BGR and BHB with moderate to heavy rainfall
over northern Aroostook terminals.

BGR and BHB likely to see LLWS through 07z tonight with HUL
tapping into LLWS between 23-02z.

SHORT TERM:
Mon: IFR cigs to continue through the day with light to
moderate rain showers across all terminals. Winds NE at 5 to 10
kts.

Mon night - Tues night: Conditions quickly improving to VFR from
north to south across all terminals. Winds N to NW around 5 kts
shifting SW Tues evening into Tues night.

Wed: Generally VFR across all terminals, with MVFR cigs moving
in to Aroostook terminals from the NW through the day. Winds SW
5 to 15 kts.

Wed night: MVFR/IFR in showers and thunderstorms. Winds SW at 5
to 10 kts with higher gusts possible in thunderstorms. Vis could
become LIFR in any heavy rain.

Thurs: Improving to VFR with lingering showers possible. Winds
W at 5 to 10 kts.
-- End Changed Discussion --

&&

.MARINE...
NEAR TERM:
SW winds will increase to SCA today and remain SCA tonight.
Humid air over the colder waters will likely result in fog and
mist across the waters today into tonight. Seas 3-4 ft today
building to 6-7 ft tonight in response to the southwesterly.

SHORT TERM: Seas will likely continue 5 to 7 ft through Monday
night, decreasing late. Winds will gust up to around 20 kts
during this time, though gusts up to 25 kts are possible in any
rain showers. Winds and seas will subside on Tuesday, but as
another storm approaches on Wednesday, gusts will surpass 25 kts
once more with seas responding into the second half of the week.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory from 5 PM this afternoon to 8 PM EDT
     Monday for ANZ050>052.

&&

$$


Near Term...Bloomer/Buster
Short Term...AStrauser
Long Term...AStrauser
Aviation...Bloomer/Buster/AStrauser
Marine...Bloomer/Buster/AStrauser