Above normal temperatures will be the rule this week across the Northern Rockies. Highs are expected to reach the 60s and 70s by Thursday. There is a brief period of snow that will affect Marias Pass Tuesday night. With the warmer temperatures, there will be a slight increase in river levels by the end of the week. A big change back to wintry conditions is possible by Saturday as a cold Canadian air mass infiltrates western Montana. This will bring cold and wet conditions which could be a threat to newborn livestock and also to sensitive vegetation. Possible valley snow with gusty easterly winds are also in the works. The worst travel conditions will be near the Continental Divide and temperatures could be as much as 10 to 15 degrees below normal in those areas.