Discussion
A trough approaching the west coast will usher in a pattern change this weekend.
The pattern over the next week will remain active with troughs moving through the region.
A closed low off the west coast is filling in and will become a trough by the time it arrives in the northern Rockies Saturday morning. A larger, stronger trough will remain off the US west coast setting up southwesterly flow into the region. The southwest flow will cause warmer temperatures and rising snow levels, and while the trough will also bring some moisture, it won't be much. Over all, it will be a breezy, wet weekend, especially in the mountains as a result.
Some cooler air will make it into the region by Monday, causing snow levels to trend down slowly, but steadily. As the broader area of troughing migrates eastward, it will bring more cold air with it, and snow levels will reach around 4,000ft late Tuesday or early Wednesday. So some light snow showers could reach valley floors in western Montana by mid or late next week.