Winter Storm Warning 12, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
302 AM MDT Thu Sep 26 2019

...MAJOR WINTER WEATHER FOR NORTHERN ROCKIES THIS WEEKEND...

.DISCUSSION...A cold front will move through the region
today..starting with rain then becoming more showery by the
afternoon. Also expect breezy westerly winds with gusts to 30 mph
today...couldn't rule out some gusts over 40 mph at Marias Pass
and also MacDonald Pass.

The historic winter event is still on tap to affect the area by
Friday night lasting into early next week. No major changes this
update except for a few more winter storm watches hoisted
(Bitterroot and Sapphire mountains and also the higher elevations
of western Lemhi County).

 - Strong to possibly damaging winds across northwest Montana. We
   have been stating wind gusts to 40 mph, but there are
   indications that higher wind gusts to 50 mph are feasible in
   the canyons along Highway 2 between Marias Pass and Kalispell and
   around Flathead Lake.

-  Strong winds will make it dangerous for recreation on area
   lakes including Flathead Lake.

-  1 to 2 feet of snow across the mountains of the Continental
   Divide. Combined with strong gusty winds, very low visibility
   would make for difficult driving conditions in the passes.
   Blizzard conditions at times are anticipated at Marias Pass and
   also MacDonald Pass.

-  1 to 4 inches of snow for lower valleys, 2 to 7 inches for
   higher valleys above 4,000 feet are possible in western
   Montana. Locations that experience the steadier snowfall could
   experience damage to tree branches and powerlines.

-  Near record cold temperatures will follow next week which will
   likely cause damage to sensitive vegetation and exposed
   irrigation systems.

The area will continue to be influenced by general troughing aloft
for the remainder of the week. High temperatures will run about 20
to 25 degrees colder than normal for this time of year.

&&

.AVIATION...Expect an increase in clouds this evening as a cold
front approaches. Rain is expected to begin at KGPI after 26/1200z
with rain expected at KMSO and KBTM between 15Z and 18Z. KSMN
will remain cloudy with a few showers through the day. The big
impact at all terminals will be strong and gusty west to northwest
winds after 26/1800z. Expect west winds 15-20 mph with gusts up
to 30 mph at times through the afternoon.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Winter Storm Watch from Friday evening through Sunday afternoon
     Butte/Blackfoot Region...Potomac/Seeley Lake Region...West
     Glacier Region.

     Winter Storm Watch from Saturday afternoon through Sunday
     afternoon Bitterroot/Sapphire Mountains.

     High Wind Watch from late Friday night through Saturday morning
     Flathead/Mission Valleys.

ID...Winter Storm Watch from Saturday afternoon through Sunday
     afternoon ABOVE 4000 FEET for the Western Lemhi County.

&&