The National Weather Service has issued a Winter Storm Warning for heavy snow, which is in effect from midnight tonight to 5 am MST Saturday.

The Winter Storm Watch is no longer in effect.

Snow will develop over the mountains of southwest Montana tonight. The snow will gradually move into the valley locations after midnight.

Snow accumulations: total snow accumulations of 4 to 8 inches are expected at lower elevations... with 8 to 16 inches expected in the mountains.

* Winds: expect winds of 10 to 20 mph... with gusts to 30 mph.

These winds could result in areas of blowing and drifting snow... especially in open areas and through mountain passes.

* Visibility: visibilities of less than one half mile in areas of heavy snow and blowing snow.

* Other impacts: expect roadways to become snow covered and slippery by the morning rush hour on Thursday. Those spending time outdoors need to be prepared for rapidly changing and winter conditions.

Locations affected include: Battle Ridge Pass... Bozeman...Bozeman Pass... Targhee Pass... West Yellowstone... Boulder...Boulder Hill... Elk Park Pass... Homestake pass... Whitehall...Townsend... Big Hole Pass... Chief Joseph Pass... Dillon... Monida Pass... Ennis... Norris Hill... Raynolds Pass... Twin Bridges.

Precautionary/preparedness actions...A Winter Storm Warning for heavy snow means severe winter weather conditions are expected or occurring. Significant amounts of snow are forecast that will make travel dangerous. Only travel in an emergency. If you must... keep an extra flashlight... food... and water in your vehicle in case of an emergency.

Source:  Weather Underground