West of the Continental Divide:
 
Not too much change to the short term forecast as a NW flow aloft will continue to keep cool temps as well as deliver a few weak disturbances with light accumulations possible through Thursday. Our first weak system arrives Tuesday afternoon/evening across mainly the mountains along and south of I-90. Discovery, Snowbowl, and Lost Trail could all see 1 – 2” by Wednesday morning.

Another fresh wave arrives out of British Columbia Wednesday morning adding another inch or two for these same locations by noon. Whitefish, Lookout Pass, and Blacktail will ride just north of these incoming systems, seeing just a few isolated flurries on Wednesday. Thursday keeps snow showers with trace accumulations possible for the I-90 and south locations with generally cloudy skies for the mountains north of the I-90 corridor. 

As the impressive high-pressure ridge over the west coast builds northward through Alaska on Thursday night, a shortwave low-pressure system will ride out of the Gulf of Alaska and south along the eastern edge of the ridge into the PNW and the Northern Rockies by early Friday morning. While there are questions on the tracking of where the heaviest snowfall will accumulate this shortwave should have sufficient Pacific moisture for widespread areas of moderate accumulations in the 4 – 8” range by Friday evening. I should have a better idea on specifics on my next update on Thursday. 

As the 900lb gorilla of an arctic cold front resides east of the Continental Divide on Friday night, yet another shortwave low descends southward out of BC. This trough is expected to draw the frigid arctic air east to west over the Divide while also providing additional Pacific moisture adding another several inches Friday night into Saturday morning. Gusty east to NE winds will kick up as the arctic air spreads into the region on Saturday. Temps at Whitefish are expected to plummet to around zero before noon on Saturday. Lost Trail and Disco will see single digit highs on Saturday as the storm system slowly clears out and arctic high-pressure begins building.    
 
 
East of the Continental Divide:

A much more active northerly flow will continue east of the Divide delivering cold temps and daily light accumulations across the mountains of SW (Big Sky, Bridger, Maverick, Red Lodge) and North Central Montana (Showdown). We have our next northerly disturbance arriving Tuesday afternoon and continuing into Tuesday night. Latest model runs show a band of snowfall setting up from Bozeman south to Big Sky where 3 – 5” by Wednesday morning looks likely. Another area that stood out was across the Little Belts where Showdown could also see similar numbers overnight Tuesday. Bridger and Red Lodge, possibly 1 – 3”. 

Clouds, cold air, and snow showers will stick around on Wednesday with accumulating snow likely at those same favored locations across SW and North Central Montana. Big Sky and Showdown could see another 2 – 4” through Wednesday night with 1 – 3” at Bridger, Maverick, and Red Lodge.   

Snow showers along with moderate and gusty W/SW winds for Thursday with light accumulations of 1 – 2” continuing across the mountains of SW and North Central Montana. 

By Thursday evening the Alaskan shortwave low-pressure system alluded to in the opening preamble will be transported north to south through Alberta and into the region east of the Divide through Friday morning. This is our snowmaker and will carry an arctic cold front on its shoulders adding gusty N/NW winds to the winter storm mix. Arriving on the same northerly flow that’s been in control all week, the heaviest snowfall amounts are likely to fall across the mountains of SW and North Central Montana. Big Sky could likely see 6 – 12” of cold smoke pow in the 15:1 (SLR) Thursday night through 4PM Friday. To the north at Bridger and Showdown, 5 – 10” are likely. Elsewhere across the region 2 – 5”, Red Lodge included. 

As the second shortwave trough ushers in more frigid Canadian air Friday night look for periods of snow to continue overnight and through noon on Saturday. This will likely add another 3 – 6” at Big Sky, Bridger Bowl, and Red Lodge, with slightly lesser amounts of 2 – 4” at Showdown, GD, Maverick, and Teton Pass. Partial clearing across the region through the afternoon on Saturday as arctic high-pressure begins to build with decreasing N/NW winds. Temps will be brutally cold on Saturday with upper mountain highs around zero at Showdown, with 5F above at Big Sky. Cold everywhere across the eastside of the Divide through the weekend.   

Below: The NBM model animation for snowfall over the Treasure State  Tuesday through 5PM Thursday afternoon shows the potential for some decent accumulations across SW and North Central Montana east of the Continental Divide. 

Below: Here’s the latest Euro model animation for projected snowfall across the state of Montana from 5PM Thursday through 5AM Sunday. Pacific moisture looks to clash with the incoming arctic airmass and hopefully will deliver as advertised. More details will be available by Thursday when my next update will be posted.   

 

West and East of the Continental Divide: 

An arctic high-pressure ridge will strengthen keeping dangerously cold surface temps and wind chills across the Treasure State from Sunday 1/29 through Wednesday 2/1 next week. A few overriding disturbances will be possible but generally this looks to be a mostly dry period. By next Thursday there appears to be some relief from the brutal cold.  

Below: Below: CPC’s 6 – 10 day forecasts keep cold temps and a continuation of unsettled skies across the Northern Rockies. 

Thanks for tuning in, my next update will be on Thursday, 1/26.  

Powder Out – 
 

Bob