Waves of heavy snow and rain will sweep over Colorado Thursday afternoon into Friday morning, according to the National Weather Service. Starting around 3 p.m. Thursday, heavy snow will fall over the mountains along and south of Interstate 70 and in areas of the southern foothills above 7500 feet of elevation, according to NWS meteorologists. The mountains will see 6 to 12 inches of snow accumulate overnight Friday, with higher snowfall amounts possible over the Mosquito Range, NWS forecasters said.