Alberta Clipper Set To Bring Bitter Cold

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FXUS61 KCAR 141449

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

949 AM EST Mon Dec 14 2020....

.....SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...

A strong arctic cold front crosses the area Tuesday and ushers in

what will by far be the coldest air of the season thus far.

Temperatures Tuesday will fall from early morning highs, and the

main concerns are strong wind and snow shower/squall potential.

There will be steepening low level lapse rates and the wind

direction from around 310 degrees is favorable for a potential

Laurentian plume to set up in the morning with a possible snow

squall that could set up from the North Woods to near or south of

Presque Isle. Even if there is no laurentian plume there will likely

be scattered snow showers across the north and mountains, and

combined with a northwest wind that will likely gust to 35 mph there

could be reduced visibility in blowing snow across the far north,

mainly areas north of Baxter State Park.  Have added blowing snow

back into the forecast for Tuesday across the north tied in with

wind gusts in excess of 25 mph. Temperatures by sunset will likely

be in the upper single digits/low teens north to around 20 degrees

Downeast.

Strong cold air advection continues Tuesday night and the wind

will slowly ease, but remain strong enough for wind chill

concerns. After midnight and until mid morning Wednesday wind

chills will likely drop to 15 to 25 below north and from 10

below to zero Downeast. A wind chill advisory will likely be

needed across the north. Wednesday will be the coldest day so

far this season with highs only in the single digits north to

the upper teens along the coast. Have continued to undercut most

of the guidance, especially across the northern half of the FA

which will be deeper in the arctic air with 925H temps of -20C,

or perhaps even a little lower.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...

High pressure in Quebec will nose down into Maine as a powerful

Nor`easter takes shape off the Delmarva coast.  If the sky is clear

in the north, the combination of snow cover, light wind that will

likely become calm in broad valleys, and a cold air mass could allow

temperatures in the normal cold spots in the nw valleys to drop to

10 to 20 below, and have tweaked the lows down a bit more. The one

caveat, especially this time of year is cloud cover.  It is always

possible that some moisture gets picked up from the Saint Lawrence

and that some lower clouds drift into far northern Maine.

High pressure remains across northern Maine as low pressure passes

near the benchmark.  High and some mid level clouds will likely

stream across southern sections of the FA, with the chance that some

snow could try to work north to the Downeast coast.  There is high

confidence that the high impact winter weather remains south of the

area, but whether it is a complete miss for the Downeast Region, or

if some snow can make it north into the region remains in doubt. The

GFS and the GFS ensembles all keep the snow south of Bangor.  There

are about a 1/4 of the ECMWF members that would bring accumulating

snow into the southern third of the FA. Will continue to stick very

close to what we have have been advertising the past three days now,

which is chance PoPs for most of the Downeast region with with

likely PoPs confined to the immediate coast and offshore.

In the wake of this system, generally dry weather is expected Friday

and Saturday with a moderation trend back to seasonable temperatures

by the start of the weekend.  The next weather system may bring a

chance of precipitation Sunday, but this far out is is looking

disorganized with a stronger southern branch low passing to our

south.  Snow would be favored over rain in the north, with rain or

snow southern sections of the FA; but at this time it is not looking

to be a significant event.

&&

Hazardous Weather Outlook

National Weather Service Caribou ME

315 AM EST Mon Dec 14 2020

MEZ001>006-150815-

Northwest Aroostook-Northeast Aroostook-Northern Somerset-

Northern Piscataquis-Northern Penobscot-Southeast Aroostook-

315 AM EST Mon Dec 14 2020

This Hazardous Weather Outlook is for Central Highlands Maine, Far

Eastern Maine, Far Northern Maine and North Woods Maine.

.DAY ONE...Today and Tonight.

Hazardous weather is not expected at this time.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

An arctic cold front will cross the region early Tuesday with a snow

squall possible. Patchy blowing snow is possible during the day

Tuesday. Wind chills may approach 20 below late Tuesday night into

Wednesday morning.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather

conditions according to Standard Operating Procedures.

$$