West of the Continental Divide:

High-pressure has triggered a NW flow aloft that will keep mainly cloudy skies in the forecast Wednesday through Thursday evening. A few sunny spells are possible Thursday afternoon at Whitefish where they will be kicking off their 75th Anniversary season in style with roughly 75% of the terrain opening. Temps will be at or slightly below seasonal averages. 

Below: The calm before opening day 22/23 at Whitefish Mountain Resort, or The Big Mountain as it is locally known. 75 years and counting. 

As a Pacific trough of low pressure moves inland across southern BC on Thursday night, snow showers will develop across the NW half of the region. Unfortunately, this system has trended weaker with each model run, and thus only 1 – 2” are anticipated at Whitefish, Snowbowl, and Blacktail by midday on Friday. Lookout Pass, and perhaps Turner Mountain, both closer to the storm’s main energy over Idaho, could see 3 – 5”. Disco and LT on the southeast fringe of this system could see a trace to a few inches by Friday afternoon. 

A W/NW flow will bring cloudy skies with isolated snow flurries on Saturday with some trace amounts possible. Lookout Pass could see an inch or two under heavier snow showers. High temps at 6000’ will range from 20 – 24 degrees. South winds 10 – 15 mph with gusts to 25 mph across the higher ridgetops, especially at Disco and LT. 

Still some timing and tracking issues to be resolved regarding the next storm system that is expected to encroach into Western Montana on Sunday. I do see some tendencies from the latest model runs for this storm to track across the southern tier (south of the I-90 corridor) of the region with Lost Trail Pass in the best position for moderate snowfall amounts. That’s 50/50 at this point so check back on Friday for more info on this developing storm system. 

East of the Continental Divide:

A weak ridge of high-pressure will bring a mix of sun, clouds, and gusty SW winds for Wednesday and Thursday across just about all mountain locations east of the Divide. A Blizzard Warning has been issued for the Rocky Mountain Front (Teton Pass) for W/SW winds to 45mph blowing the fresh snowfall from the last 24-hours and making for tough traveling conditions northwest of Great Falls. While SW winds have decreased slightly at Big Sky on Wednesday, expect them to pick up again Thursday afternoon with gusts to 30 mph. Temps will be moderating slowly but will generally be below the seasonal average with highs at 8000’ ranging from 18 – 22F for both days.   

Just a note that Bozeman’s own Bridger Bowl will commence 22/23 season operations on Friday with an above-average (110%) snowpack. A  weakening low-pressure trough is favored to encroach into the region on Friday afternoon with increasing clouds and snow showers developing through the day, mainly SW Montana at Big Sky and Bridger. Not much moisture is available so only 1 – 2” are likely (if that) across SW Montana. Winds will continue to be breezy across the alpine ridgetops, with S/SW gusts to 30 mph. Elsewhere across the Eastside, cloudy with flurries with trace amounts. Slightly colder with the passing of the front with highs around 15- 18 at 8000’. Wind chills will be cold at Big Sky and Bridger. 

Saturday will be a transition day across the Eastside with a mix of sun and clouds with continued breezy S/SW winds with gusts to 30mph. High temps around 18 – 22F at 8000’ will make for a wind chilly kind of day across the high country. 

A Gulf of Alaska storm system is anticipated to move into the region on Sunday and Sunday night bringing chances of light snow amounts as well as a reinforcement of arctic air. There still are more details that need to be worked out with this storm system, so stay tuned for my Friday update.

Below: The NBM for snowfall projections from Wednesday – Sunday night shows the most snow amounts along the western border with Idaho. Montana will be getting the leftovers from storms hitting Central Idaho and the Teton’s of Wyoming.    

  

West and East of the Continental Divide: 

The Gulf of Alaska storm system expected to move into the Northern Rockies on Sunday has the potential to drop a few to several inches across SW Montana through Tuesday. Potential is the keyword as we are not sure how this low will track through the region just yet.

One thing that the majority of the weather models are agreeing on is the establishment of a strong ridge of dreaded high-pressure blocking storms from entering the PNW through the end of next week. Cold air will reside across the Treasure State through most if not all of next week with below-average temps. Inversions are also expected to develop under this high-pressure ridge.

Below: The Euro deterministic model for the period Monday, 12/12 – Saturday, 12/17 shows high-pressure in command across the NE Pacific and across the PNW, and into the Northern Rockies.  

  

Thanks for tuning in, my next update will be on Friday,12/9.  

Powder Out – 
 

Bob