NWS Caribou, Maine Area Forecast Discussion



000
FXUS61 KCAR 190801
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
401 AM EDT Tue Mar 19 2024

.SYNOPSIS...
Low pressure slowly exits across the Maritimes today. Low
pressure tracks across the Great Lakes and southwestern Quebec
Tuesday night and Wednesday. Low pressure develops near the
coast Wednesday night, that tracks into the Maritimes on
Thursday. High pressure builds in Thursday night and Friday,
followed by a storm system approaching from the southwest
Saturday into Sunday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Still some left ovr llvl moisture tdy on the the back side of a
departing first of a double upper trof system, which will keep
clds and isold to sct lgt sn shwrs and sct flurries spcly ovr
far NE ptns of the FA, with little or no sn accumulation. The
rest of the FA will be ptly to msly cldy. High temps tdy will be
near to slightly abv seasonal norms with gusty WNW winds.
Flurries and isold sn shwrs should exit E and end across Nrn
ptns of the FA by early this Evening.

Tngt, a very skinny sfc ridge will bring ptly cldy skies and
dmnshg winds for all of the Rgn, before cldnss begins to
increase ovr far Wrn areas by daybreak Wed ahead of a stronger
Alberta clipper s/wv arriving from Cntrl Can. Low temps will be
near seasonal norms.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A very complex setup in the short term for potential impactful
snowfall Wednesday Night into Thursday.

Wednesday will feature a clipper like system diving southeast
into Quebec with warm air advection over Maine. This will likely
result in light precipitation developing with increasing
boundary layer moisture advection on SE winds. Temperatures
will be warming above freezing during the day so mixed PTypes
likely with rain south and rain/snow or snow north. Highs top
out in the low 40s south and upper 30s to around 40F north. Wed
evening there is increasing agreement with some of the
operational and ensemble members of the GFS/ECMWF and to an
extent the CMC. 500mb shortwave energy will dive southeast over
Western New England which allows for strengthening upper level
divergence over Cape Cod to Boston area. This will give way to
surface cyclogenesis somewhere north of Cape Cod to perhaps the
Portland area. ECMWF operational and ECMWF based AI model tilts
the 500mb trof negatively and rapidly strengthens the surface
low along the Midcoast and tracks it northeast into Maine. The
latest ops runs from the CMC takes the low well northwest near
Maine/Quebec border with the GFS into coastal Washington county.
Looking at the modeled thicknesses for the CMC gives strong
belief its a outlier. Opted to take a blend of the GFS/CMC which
is basically what the 00z ECMWF operational looks like taking a
low from BHB to HUL.

Wed night the boundary layer will dynamically cool as the low
deepens and colder air is drawn southeastward into Maine. Strong
agreement with some potentially heavier precip falling along and
NW of the center of the low wherever that track may be given
stronger FGEN and decent DGZ that sets up. The challenge in the
forecast going into Thursday is how fast the back edge of the
precip ends. ECMWF keeps precip going with a strong deformation
band on the backside while GFS looks more like a dry slot
shutting things off Thursday AM. Opted to stick with an NBM
blend for the day with steady precip confined across the north
with precip ending south. During the day as precip comes to an
end expect strong cold air advection to develop with the
Moosehead and North Woods areas to reach their highs before
midday before falling. W-NW winds will rapidly increase as the
pressure gradient tightens in the wake of the storm with gusts
30-40mph possible. Snowfall when all said and done looking like
3-6 inches across the northern 1/2 of the CWA with 1-3 inches in
southern 1/2.

Thursday night expect snow showers to come to an end across the
north with gradual clearing through the night. It will be a
brisk night with strong W-NW winds across the area. Winds
gusting 30-40mph with temperatures falling back into the teens
across much of the area with single digits for Moosehead and the
North Woods. Wind Chills may approach -5 to -15F across the
north and -5F to +5F across the south.


&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Friday surface high pressure will slowly build in from the west
in Quebec during the day. Pressure gradient weakens slightly but
still expected westerly gusts 25-30mph. Despite mostly sunny
skies the temperatures will be below normal in the mid to upper
20s across the north with low 30s across Central Highlands and
Downeast. This weekend features some significant differences in
the operational runs but similarities in the ensemble members
for these models. The GFS is the consistent operational run that
remains bullish on a storm system on Saturday lasting into Sun
AM with potential of Rain & Snow across the area. The ECMWF has
shifted westward with the latest runs but still a weaker system.
The CMC keeps up on the northern fringe of a more deeper storm
down in the Mid-Atlantic states with some precip. Opted to stick
with the NBM for now which is leaning closer to the ensemble
members similar to the GFS operational runs. Likely POPs on
Saturday becoming chance POPs on Sunday. Temperatures slightly
cooler than normal favor snow north and rain/snow south.
Potentially active weather continues into next week with rounds
of precipitation.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: Today...mainly MVFR clgs KFVE - KPQI with ocnl MVFR
and brief IFR vsbys in isold - sct sn shwrs. Mainly low VFR
clgs KHUL - KBHB with ocnl MVFR vsbys in sct flurries at KHUL.
Mdt WNW winds all sites.

Tngt...low VFR clgs - unlmtd VFR all TAF sites. Lgt winds.

SHORT TERM: Wed...MVFR. Possible IFR. -RASN north, -RA south.
Winds SE 5-15kt.

Wed night...MVFR/IFR. LIFR possible. -RA changing to -SN south.
Mainly -SN north. E-SE 5-10kt shifting W-NW 10-15kt late.

Thu...MVFR/IFR. -SN becoming -SHSN. W-NW winds 15-25kt with
gusts up to 35kt. LLWS possible.

Fri...VFR. W-NW winds 10-20kt with gusts up to 30kt.

Sat...MVFR/IFR possible. -SN becoming -RASN south with -SN
north. SE winds 5-15kt with higher gusts possible.

&&

.MARINE...
NEAR TERM: No hdlns xpctd Tdy thru Tngt. Max wv hts to 4 ft and
wind gusts to 22kt ovr open waters tdy, then lower winds and
wvs tngt. Kept close to blended model wv guidance for fcst wv
hts with wv pds msly between 5 and 8 sec.

SHORT TERM: Wednesday expecting S winds generally 10-20kt with a
few gusts to 25kt. Waves building 2-4ft with a period of 7-8sec.
Winds shift W overnight into Thu AM. Winds rapidly increase to
Gales behind departing storm system. Westerly gusts increase
40-45kt during the day and last into Fri AM. Seas build 4-8ft on
Thu with a period of 8-9sec. Winds fall back into SCA
conditions as they shift NW Fri AM. Seas subside 2-4ft on
Fri. Winds fall below SCA conditions Fri night. Next chance of
SCA conditions are Sat-Sun with another storm system. In terms
of precipitation, expect rain on Wed becoming Rain/Snow mix
late Wed Night and then Snow by Thu AM which may reduce vsby at
times. Additionally, Light Freezing Spray will be possible late
Thu night into Fri AM.

&&

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

&&

$$


Near Term...VJN
Short Term...Sinko
Long Term...Sinko
Aviation...VJN/Sinko
Marine...VJN/Sinko

NWS CAR Office Area Forecast Discussion