The current weather pattern across the United States can be compared to a pancake about to be flipped. The West has been completely cooked, and now the East will be flopped down on the grill. As the warmth vacates the West, colder air will come down from the north. The turn to colder will be most pronounced across the northern Rockies and Northwest.

Thursday and Friday, snow will fall from Idaho across Montana and northwestern Wyoming. At ski resort elevations, snow accumulations will reach 12 inches or more; lower elevations will get much less.

Story by AccuWeather.com Expert Senior Meteorologist John Kocet.