MISSOULA — Portions of western Montana are seeing very light snow showers this morning. Generally only light snow amounts are expected with the exception of mountain passes. Lookout and Lolo Passes have seen a couple inches over night, and will likely see another 2 inches or so through the early morning hours. Winter Weather Advisories for Interstate 90 and Highway 200 west of Missoula remain in effect through 9AM this morning.
An unstable atmosphere will remain over the Northern Rockies through this afternoon. This instability will allow showers that will be capable of producing intense snow/graupel to develop for brief periods of time. Due to the daytime heating, impacts to roads will be minimal, though visibility will be reduced as the showers move overhead.
A stronger weather system will bring in widespread snow Saturday. Precipitation will start in west-central and southwest Montana Saturday morning then move into northwest Montana Saturday afternoon. Valley locations along and south of I-90 may see precipitation fall as a rain/snow mix for a time Saturday afternoon before turning back to snow Saturday night. Locations north of I-90 will see precipitation fall as all snow. Snow accumulations of a few inches will be possible for all of western Montana by Sunday morning. 4" or more looks likely over those mountain passes.
After a brief break from the showers Sunday and Monday. Our next system will bring another round of mountain snow and valley rain/snow by Tuesday of next week. While specific details remain unclear, another windy day is looking likely for next Tuesday as well. More details to come through the weekend.