Wind Advisory 1, NWS Missoula, MT

191 
WWUS75 KMSO 032344
NPWMSO

URGENT - WEATHER MESSAGE
National Weather Service Missoula MT
444 PM MST Mon Jan 3 2022

IDZ008-040045-
/O.EXP.KMSO.WI.Y.0001.000000T0000Z-220104T0000Z/
Lower Hells Canyon/Salmon River Region-
344 PM PST Mon Jan 3 2022

...WIND ADVISORY WILL EXPIRE AT 4 PM PST THIS AFTERNOON...


$$

Area Forecast Discussion
National Weather Service Missoula MT
306 AM MST Sun Jan 2 2022

.DISCUSSION...Today will be the final day of dry and sunny
conditions thanks to high pressure, resulting once more in brisk
high temperatures and very cold morning temperatures. The thing to
pay attention to today will be the increasing winds expected
across the Camas Prairie in Idaho, including the Highway 95
corridor from Whitebird Grade to Cottonwood. Winds have already
begun to transport snow in these areas and as winds strengthen
today into Monday, ground blizzards will become an increasing
concern with time. Periods of reduced visibility in the
aforementioned locations will impact those traveling from now
through Monday afternoon. Winds exceeding 50 to 60 mph will be
common, particularly Monday.

Elsewhere, winds will increase in terrain across the region above
6000 feet, creating inclement backcountry conditions due to strong
winds and transporting snow. No new snowfall is expected today
for the Northern Rockies, but that will change late in the day on
Monday as moisture from the PacNW moves inland late Monday through
Tuesday. Though forecast models keep delaying the onset of precip,
mountainous terrain along the Idaho/Montana border will begin to
pick up appreciable snowfall long before valleys see any
accumulations. The strong winds aloft will play a part in this;
thus limiting snowfall down to valley surfaces.

Snow will become more sparse and showery in nature late Tuesday
through Wednesday before the next round of snow enters from the
west. Before then, cold arctic air will attempt to make its way
west of the Continental Divide. As it does so, temperatures along
the Divide and into northwest Montana will drop back down to
frigid values (single digits and low teens for high temps). How
far westward this frigid air progresses is yet to be seen, but
could make it as far west as the ID/MT border.

An Atmospheric River entering onto the Washington and Oregon
coasts on Thursday will eventually translate into moderate to
heavy mountain snowfall Thursday through the weekend for the
Northern Rockies. As a result, valley snow will become more and
more of a likelihood by Friday, particularly west central Montana
and northwest Montana, as precipitation increases and shifts
northward. Valley accumulations in central Idaho valleys may mix
with freezing rain or rain for a time Thursday morning, creating
additional travel impacts.

All in all, the mountains stand to pick up a few feet of new snow
from late this week into next weekend, with valleys seeing
additional snowfall as well.

&&

.AVIATION...Sunny and dry conditions will exist today across the
Northern Rockies. Strong winds aloft will plague the airspace
across the region, with strong surface winds of 40 to 50 knots out
of the south impacting KGIC today through roughly 02/20Z.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...Winter Storm Warning until 4 PM PST Monday Orofino/Grangeville
     Region.

&&