* WHAT...Moderate to heavy snow expected. Total snow accumulations up to 10 inches. Winds gusting as high as 45 mph. * WHERE...In Montana, Pryor/Northern Bighorn Mountains. In Wyoming, Northeast Bighorn Mountains. * WHEN...Until 8 PM MST Monday. * IMPACTS...Snow and blowing snow will make back country recreation and travel along Highway 14 through the Bighorn Mountains very difficult. Visibilities may drop below 1/4 mile due to falling and blowing snow. * ADDITIONAL DETAILS...The heaviest snowfall is expected Monday morning.