Dynamic Storm to Produce Significant Snow & Beneficial Rain

Posted at 6:00 PM, May 18, 2021
and last updated 2021-05-18 20:43:30-04

A WINTER STORM WARNING has been issued for the East Glacier area and the Rocky Mountain Front.
A WINTER WEATHER ADVISORY has been issued for areas of central and western Montana. This does not include the Helena Valley at this time.

A strong cold front that brought strong wind and isolated showers/storms to the state on Tuesday will set the stages for our significant spring storm. This storm and the expected snow will be heavily dependent on elevation. As the elevation can change rapidly across a short distance, expect precipitation type to change rapidly at times as well. Wednesday will start off quiet but clouds will increase through the day with rain showers developing near the Continental Divide. Some snow will mix in over the higher terrain. Rain will increase in western and central Montana through Wednesday evening. At the same time, colder air will be drawn into the system with lowering snow levels through Wednesday night into Thursday morning. Thursday will be cold and sloppy with a mix of rain and snow falling across much of north central Montana and down along the Continental Divide. The snow will accumulate several inches in the lower elevations through the day along the Rocky Mountain Front and in the mountains. Travel will be difficult with the wet snow sticking on road surfaces in the mountains.The lower elevations like Helena and Townsend will largely experience rain on Thursday. Great Falls will have a mix of rain and snow. Northeast Montana will experience solid rain, helping the drought situation there. Highs will be much colder, only in the 30s and 40s across most of Montana. The mountains will only top out in the 20s and low 30s. As colder air is drawn into the system, snow levels will continue to drop on Thursday night with more areas seeing a transition to snow. Snow will continue Thursday night into Friday morning before beginning to break up through the day. High temperatures will warm into the 30s and 40s, with some 50s in eastern Montana. The storm system will split on Saturday giving much of the state a break from rain and snow. Skies will be mostly cloudy, highs will be cool in the 40s and 50s. A few isolated showers and mountain snow showers are possible. Another round of rain and isolated thunderstorms will move through on Sunday. The storm will begin pulling away on Monday with wind and areas of rain still moving through the state.

Stay tuned for updates on this storm as we get closer to the event.

Curtis Grevenitz

Chief Meteorologist