Snow is in the forecast for the northern Rockies, and the source of moisture behind the powder may surprise you.

Winter is arriving early across the Northern Rockies as cold air meets up with a plume of moisture from Tropical Storm Rachel.

The heaviest snow is expected across the higher elevations of central Montana, where 10 to 20 inches could fall through Sunday morning. Snow-covered roads and reduced visibility could make travel difficult, especially through mountain passes.

While lower elevations may see more rain than snow, higher terrain could become a winter wonderland. Anyone heading into the mountains this weekend should prepare for rapidly changing conditions and potentially hazardous travel.