Two waves of heavy snow will hit the Helena area over the next two days as a winter storm continues to move across the region.

Following moderate accumulation that started on Wednesday, snowfall was expected to resume Thursday afternoon and continue into Friday morning. The National Weather Service in Great Falls forecast 2-4 inches in the Helena Valley with heavier accumulations in the mountains as part of the first system, said meteorologist Jim Brusda.

Starting Friday afternoon and continuing into Saturday, a second system is forecast to hit the region and drop another 4-7 inches in the valley and 8-10 inches from Mount Ascension to McDonald Pass, he said.

“The most pronounced period of snow begins during the Friday evening commute,” Brusda said. “The good news is there’s no school this week which will cut down on traffic, but this long holiday weekend could also mean some additional traffic.”

With southwest and north-central Montana under a winter storm warning through Saturday, the brunt of the storm is forecast to hit McDonald Pass west of the Continental Divide and north to Glacier National Park. McDonald, Rogers and Marias passes and the Lincoln area could see 15-30 inches of snow. Between 15 and 20 inches is more likely for McDonald Pass, Brusda noted.

“We do believe with the lull between the two systems that the state should be able to keep up with snow removal, at least in our area,” he said. “That may be different in other parts of the state like out by Billings with blowing snow.”

As the storm moves out Saturday, temperatures are expected to fall back below zero. The current forecast calls for lows of minus 6 and minus 5 degrees Fahrenheit, although it could dip a bit lower, Brusda said.

North-central Montana will see the coldest temperatures with lows closer to 20 below zero.

Warmer weather with highs in the 20s is expected to move into the region early next week.

Reporter Tom Kuglin can be reached at 447-4076 @IR_TomKuglin