A large winter storm will impact much of the Rocky Mountain region through at least midday Friday. This storm will begin to take aim on areas east of the Continental Divide in Wyoming tonight and Thursday. A vigorous arctic cold front will bring much colder temperatures and snow to the basins and plains of Wyoming early Thursday through midday Friday. This arctic front will plunge south from Montana early Thursday pushing through central Wyoming by daybreak. The snow will spread from north-to-south behind the cold front which will be packing gusty north to northeast wind of 20 to 30 mph.
Winter storm warnings have been posted for most of Natrona County, the Lander Foothills, and the eastern Wind River Mountains. Winter weather advisories have also been posted for most other locations east of the Divide, with the exception of the northern and central Big Horn Basin. By Friday, high temperatures will be in the single digits, some 30 to 40 degrees below high temperatures early this week.
Snow will continue to fall across the western-quarter of Wyoming into this evening. Snowfall in Jackson Hole and in the northern Star Valley has generally ranged from 5 to 8 inches, thus far. The north end of Jackson Hole, from around Moose toward Colter Bay, has seen snowfall of 8" or more. Reports from Wilson to Hoback Junction indicate more than 8" at those locations. From around Afton to Cokeville amounts have generally been between 1 and 3 inches. Additional snowfall of 1 to 2 inches will be common by day's end.
In the mountains, SNOTEL estimates and observed reports show total snowfall of 8 to 14 inches. The snow will continue through this evening with another 2 to 4 inches anticipated in the higher elevations. Snowfall is expected to gradually diminish by this evening and end by early Thursday. Winter storm warnings and winter weather advisories remain posted until midnight tonight from Yellowstone National Park south through both Teton and Lincoln counties. This area includes Jackson, the Star Valley, and Cokeville. A county-by-county storm total snowfall table is available here.
Earlier Wednesday, the large winter storm generated strong winds. Wind gusts across central Wyoming Wednesday morning ranged from 50 mph to nearly 70 mph. Observations from Casper-Natrona County International Airport indicated peak wind gusts of 59 to 67 mph between 4:30 and 9:30 this morning. Speeds slowly decreased early Wednesday afternoon with sustained speeds of 30 to 40 mph and gusts around 50 mph. Click here for a comprehensive statewide map of surface observations.
Stay up-to-date with current developments and trends regarding this storm system. Visit the Wyoming Department of Transportation road and travel website or call 1-888-WYO-ROAD (1-888-996-7623) for the latest road conditions. A chain law is in effect over Teton Pass on Wyoming Highway 22. Visit our complete webcam listing to view sites across western and central Wyoming. This weather system will have major impacts on travel across not only Wyoming, but a several state region, through at least Friday. For weather updates from surrounding states visit www.weather.gov.
- Web story last updated at 2:45 p.m. Wed., Dec. 29 -