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000
FXUS61 KCAR 211640
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1240 PM EDT Sun Apr 21 2024

.SYNOPSIS...
A strong cold front will approach today and cross the area from late
tonight into Monday morning. High pressure then crests over the
region into Monday afternoon, then slowly slides to the east
into Tuesday. Low pressure will approach Tuesday night, cross
the area Wednesday, then slowly exits into the Maritimes through
Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
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12:40PM Update...No major changes. Increasing clouds across the
area with mainly cu & stratocu. Area radars showing numerous
shower activity developing across the Maine/Quebec border
northwestward into Quebec. This is in response to a vigorous
cold front dropping southeast in Quebec causing increased
surface lift combined with cooler air aloft. Expecting rain
showers to develop with some snow or graupel to mix in across
the north today. Elsewhere, generally just partly sunny skies
for the rest of the area with some sprinkles.

9:20AM Update...Minor tweaks to the ongoing forecast. Daytime
convective field of cu has started across the North Woods mainly
N&W of Baxter region. CBW radar data along with Canadian Radars
indicating showers developing over Quebec and expecting
additional convective showers to develop as we warm the boundary
layer this late morning. Have lowered the Td across the Central
Highlands, Bangor Region, Downeast and Eastern Aroostook where
the atmosphere will likely mix up to 800-750mb which will result
in drier surface conditions in these locations. Lower RHs into
the 30-35% range with westerly winds gusting 15-20mph will need
to be watched for any fire weather concerns with drying fuels.
The Maine Forest Service has placed the entire area in a
Moderate category for Fire Danger today. No other major
changes...

6:10 AM Update...The clear, tranquil and dry air has allowed
temps to fall below freezing in many areas, especially in the
valleys. Adjusted temps down early this morning. Latest HRRR and
Meso-NAM models are showing low top convection developing around
2 PM this afternoon. Expanded area of isolated showers a bit
further south and kept scattered showers in across the north.
Convection will probably be too shallow to allow for thunder,
but some isolated graupel or small hail may be possible,
especially across the north.

A thin ridge of high pressure will be to our south today while a
strong Arctic cold front ahead of a cold trough of low pressure
approaches from Quebec. Some relatively cooler air in the mid
levels will slide across the region ahead of the front this
afternoon while surface temperatures rise into the low to mid
50s. This will produce some steep lapse rates up to just over
10K ft this afternoon including capes up to 50 J/KG. There is
not much moisture available, but possibly enough for some
isolated to scattered showers, mostly across the north.

The cold front will reach the northwestern part of our region
after midnight and push across the area during the early morning
hours Monday. A brief gusty shower of graupel or snow is
possible with the front, mostly over the northwest as the front
pushes in during the pre-dawn hours. Unseasonably cold Arctic
air will surge into the area from the northwest following the
frontal passage early Monday morning with temperatures by dawn
down to near 20 over the far north to around freezing in the
central Penobscot Valley.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH TUESDAY/...
The region is at the base of a negatively tilted northern
stream trough Monday morning that should lift northeast into the
Maritimes during the day on Monday. The last shortwave to
impact the region rotating around the base of the trough passes
Monday morning. This could bring some isolated snow showers or
flurries to the North. Monday will be noticeably cooler, with a
shallow cold air mass moving in. Most MOS and non-high
resolution models do not handle this well, so went with blend of
18th to 25th percentile for temperatures temperatures.

Highs Monday should struggle to reach the lower to mid 30s
across the north and the lower to mid 40s Downeast. These values
are around 15-20 degrees below normal across the North and
around 10-15 degrees below normal across Downeast and the Bangor
region.

NW winds gusting to 20-30 mph, coupled with the cool
temperatures, will cause wind chills in from around 20 to the
mid 20s across the North and in the lower to Mid 30s across
Downeast Maine in the afternoon. Wind chills Monday morning
across NW portions of the region should be in the single digits.
This is unusually low for this time of year.

The flow aloft transitions to SW Monday night, with SW flow
aloft continuing through Tuesday night.

With dry low mid levels and no shortwaves of note progged to be
embedded in the flow through at least Tuesday evening, it should
be dry Monday night through at least Tuesday evening as a
result. The models then differ on how quickly precipitation
moves in after midnight Tuesday night, with the high resolution
models slower than the global models. Leaned towards slower
timing of high resolution models, as they typically have better
handle on the details.

Lows Monday night should be around 10 degrees below normal,
ranging from the upper teens to around 30. Highs Tuesday should
be within a few degrees of either side of normal and lows
Tuesday night slightly above normal.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A full latitude trough builds in Wednesday, then slowly exits to
the east then northeast through the Maritimes Wednesday night
and slowly as it develops into a closed low. This should result
in a period of rain Wednesday that mixes with then changes to
all snow from NW to SE before ending, for all but coastal
Downeast, from Wednesday afternoon through Wednesday night.
Some isolated to scattered rain or snow showers should linger
across mainly the North on Thursday as the upper low gradually
pulls away. At this time, it appears any snow accumulations
should be light and be located mainly across the North,
especially over the northwestern zones.

The region remains on the backside of the departing upper low
Thursday night, but with drying low to mid levels, it should be
precipitation free.

Deep layered ridging builds in Friday through Saturday, with
associated subsidence keeping things dry.

Temperatures should be near to a few degrees below normal
Wednesday night, below normal Thursday-Friday night, then near
to slightly above normal Saturday.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
NEAR TERM:
VFR conditions are expected across the area today into tonight
with the isolated exception of any showers today, or snow
showers over the north late tonight. Winds SW around 10 kt
today with higher gusts in any showers. Winds SW around 5 kt
this evening, becoming NW around 10 to 15 kt with higher gusts
very late tonight.

SHORT TERM:
Monday to Tuesday Evening...VFR. W-NW winds G15-25KT possible
Monday. S-SW winds G15-25KT possible during the day on Tuesday.
LLWS possible Tuesday evening.

Late Tuesday night-Wednesday night...IFR or lower developing
late Tuesday night/Wednesday morning from NW to SE, improving to
MVFR or VFR late Wednesday night, except for possibly at N
terminals. LLWS possible late Tuesday night/Wednesday. S-SE
winds G15-25KT possible Wednesday. W-NW Winds G15-25KT possible
late Wednesday night.

Thursday...VFR, except MVFR or lower possible in any snow/rain
showers across the North. NW winds G20-30KT possible.

&&

.MARINE...
NEAR TERM: Winds will be below SCA today into this evening, then
may reach SCA with NW gusts over 25 kt late tonight. Seas will
be up to 3 ft today and 4 ft tonight.

SHORT TERM: SCA conditions on the coastal ocean waters into
early Monday afternoon, with a few gusts to 25 kt possible on
the intra-coastal waters. Sub-SCA conditions should then follow
on all waters through at least Tuesday morning. There is a
chance for SCA conditions to develop on all waters Tuesday
afternoon and then continue on into Tuesday night.

For now it appears that all waters should be below SCA
conditions on Wednesday. SCA conditions then could possibly
returning to the coastal ocean waters Wednesday night through
Thursday night, with an event lower chance (to low to include in
the forecast for now) for SCA conditions for the intra-coastal
waters during this time frame.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory from 4 AM to 2 PM EDT Monday for ANZ050-
     051.

&&

$$


Near Term...Bloomer/Sinko
Short Term...Maloit
Long Term...Maloit
Aviation...Bloomer/Sinko/Maloit
Marine...Bloomer/Sinko/Maloit