-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCAR 240155
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
955 PM EDT Tue Apr 23 2024

.SYNOPSIS...
Low pressure will approach tonight, cross the area Wednesday,
then exit across the Maritimes Thursday. High pressure will
build across the region Friday into Saturday. High pressure
should exit by Sunday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
955 pm update...
Dry airmass per 00z raob out of CAR. Latest hires models are
slowing timing of rain by about an hour or two, thus have made
adjustments to pops and sky cover with this update though very
minimal impact on temp forecast for the overnight hours.

Prev discussion blo...
The upper level low pressure will advance a surface boundary
towards the region tonight. RH models show the low cloud deck
moving into the NW by this evening and pushing SE throughout the
night. High res models and extended QPF models show the rain
moving into the North Woods after midnight. However with the
very dry airmass ahead of the system, the rain will fight with
this airmass to make it to the ground. Decided to keep likely
rain chance out of the forecast until Wednesday morning when
dewpoints increase with the clouds.

By Wednesday, the surface low pressure will move through the
area throughout the day. By the morning, the rain will start to
increase with center of the low swinging through. The 925mb
model temps show a very tight temp gradient along the boundary
of the system. By the early afternoon, the cold airmass will
move into the North Woods, then move quickly towards the SE.
Since the system is expected to intensify, it will also pick up
speed, which will create a thin rain/snow transition line as it
moves through the Central Highlands by the evening. In addition,
NW winds will increase with the transition to snow making for a
breezy afternoon and evening. Caution will be needed Wednesday
evening with the cold temps, wet snow, and clean untreated
roadways.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Precipitation will end early Wednesday evening from west to east
as the system quickly moves off to the east. There is still
some uncertainty on when exactly the precip ends, but general
consensus is it ending around mid-evening for all. The
precipitation will be ending as snow most places thanks to very
strong cold advection, except as a light mix for Downeast.
Accumulations generally 2 inches or less are expected for the
storm in the north, with amounts over an inch generally being
north of Houlton. Winds will also be gusty from the northwest to
around 30 mph Wednesday night. The biggest concern is roads
potentially freezing as temperatures quickly fall easily below
freezing Wednesday night. The biggest threat of this is in the
north. Temperatures in the north will be down to the mid to
upper 20s by about midnight, and to the low 20s by dawn
Thursday. Temperatures will also be falling below freezing
Downeast and can`t totally rule out icy roads there as well, but
the gap between the precipitation ending and temperatures
falling below freezing is a bit larger there which could give
roads a chance to dry out.

Thursday will be mostly sunny and breezy with NW winds still gusting
20-30 mph. Airmass moderates a bit, with highs in the low to
mid 40s north and around 50 Downeast. Very dry airmass with
dewpoints down to the low teens.

High pressure builds in Thursday night and Friday. Still looks
cold Thursday night thanks to good radiational cooling with
lighter winds. Then warming to the 50s Friday, still with mostly
sunny skies.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Warming trend continues into Saturday with weak ridging aloft
building into the region. Highs Saturday will likely top 60 for
most areas. Continued dry with a good amount of sun Saturday.
Model agreement then goes downhill a bit regarding whether the
ridging can hold on into Monday or begin to break down by late
Sunday. Went with chance of rain Sunday/Monday, but there is
also a realistic possibility that we could stay dry into Monday.
More confidence in ridging aloft breaking down into more
unsettled zonal flow or perhaps weak troughiness toward
Tuesday/Wednesday, with increased rain chances. Airmass is
looking easily too warm for any snow in the extended forecast.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: VFR conditions expected through the overnight hours.
KFVE will drop to MVFR cigs after 13z and quickly switch to IFR
snow by 16z. KCAR and KPQI will see MVFR conditions around 15z
with light rain before switching over to snow 20z.

Further south MVFR conditions hole off until closer to 17z Wed
before light rain moves in. Expect rain continues through end of
TAF period.

Northern Aroostook terminals will see another night of LLWS at
FL020 from 21040kt. KFVE likely to see wind shear diminish
around 07z with KCAR and KPQI experiencing wind shear from
03-09z.

SHORT TERM:
Wednesday Night...Possible IFR early over far Eastern Maine to
begin with snow and low ceilings, but all areas should improve
to VFR by 3-6z, and remain VFR through the rest of the night. NW
wind 10-15 kts with gusts to 25 kts.

Thursday...VFR. NW wind 10-15 kts with gusts to 25 kts.

Thursday Night to Saturday...VFR. Generally W wind 5-10 kts.

Sunday...VFR with potential of MVFR, but low confidence. S wind
10 kts.

&&

.MARINE...
NEAR TERM: Winds and sea should remain below SCA conditions
tonight and Wednesday. Winds and seas will start to approach SCA
by the late evening Wednesday.


SHORT TERM: Small craft winds/seas very likely Wednesday night,
with small possibility of gales from the NW. Conditions falling
below small craft by midday Thursday, and remaining below small
craft through Saturday. Possibility of small crafts toward
Sunday.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.

&&

$$


Near Term...Buster/LaFlash
Short Term...Foisy
Long Term...Foisy
Aviation...Buster/LaFlash/Foisy
Marine...Buster/LaFlash/Foisy