National Weather Service Riverton WY
312 PM MST Sun Dec 30 2018

...Strong winter storm to bring snow, cold, and wind Sunday night
into Monday...

.Periods of moderate to heavy snow are likely to continue through
sunset Sunday before slowly diminishing Sunday evening across far
west Wyoming. The snow will spread east of the Continental Divide
Sunday evening and overnight. Windy conditions will create
hazardous travel conditions for much of the area east of the
Divide Sunday night. Bitter cold wind chill temperatures will
also occur across central Wyoming Sunday night and Monday morning.
Very cold temperatures will be over the area Monday night into
Tuesday.

Star Valley-Salt River and Wyoming Ranges-
Including the cities of Afton, Alpine, Star Valley Ranch, Thayne,
and Fossil Butte National Monument
312 PM MST Sun Dec 30 2018

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 9 PM MST THIS
EVENING...

* WHAT...Moderate to heavy snow. The north end of the Star Valley
  can expect an additional 1 to 3 inches with an additional inch
  or so across the south end of the valley. Total snowfall will
  range from 6 to 10 inches in the north, with 3 to 6 inches in
  the south. Local totals of 10 to 14 inches expected around
  Alpine. Additional mountain snowfall will range from 3 to 6
  inches.

* WHERE...Star Valley and Salt River and Wyoming Ranges.

* WHEN...Until 9 PM MST Sunday evening.

* ADDITIONAL DETAILS...Plan on snowpacked and icy roads. Patchy
  blowing snow could significantly reduce visibility.