This storm isn't supposed to stick around very long but tonight and tomorrow could see decent snowfall and much colder temperatures for Southwest Montana. Details here:

A Winter Weather Advisory for snow and blowing snow remains in
effect from 6 PM this evening to noon MST Thursday.

Timing and main impact: a cold front will move south through the
region this evening... shifting winds to the north and bringing
falling temperatures. Snow will develop over southwest Montana
behind the front this evening... and then continue through
Thursday morning.

Snow accumulations: total snow accumulations of 2 to 4 inches
are expected at lower elevations... and 5 to 8 inches in the
mountains.

Winds and visibility: north winds at 10 to 20 mph combined
with falling snow will reduce visibilities to less than one
half mile at times.

Other impacts: expect areas of blowing snow... with untreated
roadways becoming snow covered and icy.

Locations affected include: White Sulphur Springs... 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.

Winter Weather Advisory through Thursday at noon