MISSOULA — Thursday will be a clear and chilly day across the northern Rockies. Highs will top out mostly in the 30s with sunny skies overhead.
Our next system is expected to move in Friday night as a strong cold front moves through the region.
Snow will develop first across northwest Montana Friday afternoon and evening. The winds will also pick up Friday night leading to blowing snow and reduced visibility.
Snow will then shift into west-central and southwest Montana Friday night through early Saturday morning. Wind will develop here as well as the cold front moves through Saturday morning. As it does, blowing snow, reduced visibility and difficult travel is expected.
As this is a fairly large system widespread snow totals of 3"-to-8" looks likely for all valleys across western Montana, 8"-to-12" for the higher elevation valleys like Seeley Lake, Philipsburg and Georgetown Lake and 10"-to-18" for all mountain passes.
Overall expect difficult travel Friday night through Saturday due to snow and blowing snow. Winter Storm Watches have already been issued for all locations across western Montana.
Dangerous travel is expected along I-90 from Lookout to Homestake Pass and the Highway 93 corridor extending from northwest Montana south through the Bitterroot Valley.
We have high confidence with this upcoming system as all models are in good agreement for snow, wind and cold.
The one thing that is still in question and will play a big impact on snow is for the Bitterroot Valley. Temperatures will be able to warm into the upper 30s to low 40s Friday.
When exactly the cold air moves in Friday night will play a major role in snowfall totals. Right now models struggling as to when exactly precipitation will turn to all snow.
Precipitation may start out as snow, then change to a rain/snow mix or all rain before turning back to snow.
If this happens this will lead to much smaller snow totals through the Bitterroot Valley. This is something we will just have to watch moving forward.
Along with the snow, record cold air will also move in this weekend. Lows Saturday and Sunday morning will drop below zero or the single digits across western Montana with potentially dangerous wind chill values as well.
Temperatures will begin to warm Monday with highs eventually returning to the 40s by Wednesday of next week.