Area Forecast Discussion
Issued by NWS Caribou, ME
FXUS61 KCAR 091649
Area Forecast Discussion
National Weather Service Caribou ME
1149 AM EST Fri Dec 9 2016
An Arctic cold front will move through the region this afternoon.
The first Arctic air mass will settle over the area for the
weekend. Low pressure will approach Sunday night into Monday with
the threat of winter weather.
.NEAR TERM /THROUGH TONIGHT/...
Adjusted pops to account for flurries this afternoon and increased
winds later this afternoon into Saturday morning. Wind chills will
drop below zero tonight and continue into Saturday morning.
Temperatures will start falling this afternoon and continue
falling all night due to cold air advection as the Arctic air mass
settles over the area. In terms of snow squalls with the Arctic
front, most of the risk will be north of Houlton this evening.
Guidance is not resolving much of anything with all moisture and
instability confined to levels below H850. Used isolated to
scattered coverage to highlight the risk later this afternoon
through the evening.
Strong cold advection can be expected today as an arctic
front crosses the region from the west. The 00z Caribou raob
showed 850 temps around -9C with 850 temps expected to fall to
around -16C by this evening. Temperatures today are not expected
to rise all that much from current readings and then begin to drop
off by afternoon with the passage of the boundary. Winds will
become northwest at 10 to 20 mph with gusts to 30 mph. Expect
mainly cloudy skies across the north today with scattered snow
showers expected as the colder air works into the region. Across
down east expect partly sunny skies with nothing more than a few
flurries. Any snow accumulation across the north today should be
less than an inch. The exception will be in any heavier snow bands
that set up later this morning where we could see localized
accumulations of an inch or two. Liked the way the Canadian
Regional was handling things early this morning as its qpf
depiction was matching up well with current radar early this
Tonight will be partly to mostly cloudy across the north with
a lingering snow shower possible this evening, and partly cloudy
to mainly clear skies expected across downeast. Low temperatures
tonight will be about 10 degrees below normal for this time of
year. Expect lows to range from the single digits above zero
across the north and around 10 degrees across downeast. Northwest
winds at around 10 mph will make it feel even colder.
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Sat looks to be the coldest day time hi temps for the season so
far with cont`d llvl cold advcn as evident by brisk NW winds and
producing wind chills as low as single digits below zero across
the N. St Lawrence seaway sn band streamers will conts msly across
the N and W, but increased subsidence alf will will keep cld tops
low, likely lmtg intensity by this tm, with many lctns between
bands likely to experience some sunshine. Kept max PoPs msly in
the slgt chc category for now.
Ptly cldy skies and sct flurries will likely cont Sat ngt into Sun
as wind diminish. With only pockets of mclr skies, the potential
for radiational cooling will be lmtd Sat ngt. Temps will remain
sig below avg thru these pds.
Sun ngt will begin mclr to ptly cldy, then will become cldy from
SW to NE across the region late as low pres from the great lks
apchs with lgt snfl just reaching wrn ptns of the FA prior by
daybreak Mon. Ovrngt lows will be coldest across the N where winds
will be lgt and thicker cld cvr last to arrive late Sun ngt.
.LONG TERM /MONDAY THROUGH THURSDAY/...
All longer range models are in much better agreement with the tmg
and evolution of sn associated with sfc low pres apchg from the
great lks. The consensus of these models (supported by ensm data)
indicates ovrrng warm advcn snfl slowly spreading newrd thru
Cntrl ptns of the region Mon morn and then across the N by Mon
aftn. Downeast ptns of the region will likely experience the most
snfl from this system from deep layer warm advcn, and even though
secondary cyclogenesis occurs alg the Maine coast, enough llvl
maritime air will likely result in some mixed rn/sn or even a pd
of all rn alg the immediate Downeast coast and outer islands later
Mon aftn into eve, somewhat reducing max potential snfl. Across
the N, sn will begin lgt Mon aftn but will likely somewhat
increase in intensity Mon ngt as a deformation band develops in
response to an upper lvl low at arnd 700 mb forming ovr our
region. The upshot of all this is that we increased max PoPs to
categorical for most of our region with this event with max PoPs
occurring across the S durg the day Mon and across the N Mon ngt.
Wntr wx advs will be likely for most of the region, with an
outside chc of wntr stm wrngs, with lengthy duration of lgt to
mdt snfl potentially precluding the issuance of wrngs, assuming
models do not waver much from this latest consensus of solutions.
Sn should taper to sn shwrs from SW to NE ovrngt Mon into erly Tue
morn, followed by a break in the action later Tue into Tue ngt.
The next chc of sn shwrs will be Wed into Wed eve ahead of the
next arctic front. The 00z dtmnstc model run in particular
indicates the possibility of a sfc wv of low pres forming alg the
front Wed ngt that could result in more organized snfl spcly for
ern ptns of the FA prior to the arctic air arriving to the region
by Thu morn, but other models like the ECMWF keep any organized
snfl E across the Can Maritimes. For now, we will keep the mention
of chc sn shwrs and will wait for later model runs for better
consensus. Temps will be milder Tue and thru Wed eve, and then
will turn sharply colder late Wed ngt into Thu as what looks to be
the next coldest air mass of the season so far enters our FA from
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
NEAR TERM: Generally VFR conditions expected through tonight. The
only exception will be in any localized snow showers that could
affect the northern terminals resulting in brief MVFR/IFR
conditions at times today. Gusty northwest winds can be expected
SHORT TERM: Msly VFR across the TAF sites Sat thru Sun with brief
MVFR/IFR clgs/vsbys with any sn shwrs across Nrn sites spcly day
Clgs/vsbys will then lower from S to N across the TAF sites late
Sun ngt thru Mon morn in organized snfl and will cont into Mon
ngt...with Downeast sites improving to MVFR late Mon ngt as sn
moves NE into Nrn Me. Downeast sites improve to VFR on Tue while
Nrn TAf sites improve to MVFR by Tue morn as steady snfl ends as
sct sn shwrs.
NEAR TERM: Decided to hold with a strong small craft advisory
today and tonight. Do think we will see a few gusts to 35 Kt this
afternoon and into early evening as the colder air crosses the
water but think we wont see persistent gale conditions. Light
freezing spray will be possible late tonight.
SHORT TERM: Strong SCA conditions will cont ovr our waters on
Sat with cold advcn NW winds and then slowly diminish Sat ngt and
Sun morn, with lgt fzg spy ending by Sat aftn. The next chc of
hdln conditions will be Mon into Mon ngt with ESE winds ahead of
the low pres system apchg from the great lks. Kept close to WW3 wv
guidance for fcst wv hts.
MARINE...Small Craft Advisory until midnight EST Saturday night for