WWUS45 KRIW 181846 WSWRIW URGENT - WINTER WEATHER MESSAGE National Weather Service Riverton WY 1246 PM MDT Mon May 18 2026 WYZ016-017-182000- /O.CAN.KRIW.WW.Y.0019.000000T0000Z-260519T0000Z/ Upper Wind River Basin-Wind River Basin- Including the cities of Shoshoni, Riverton, and Dubois 1246 PM MDT Mon May 18 2026 ...WINTER WEATHER ADVISORY IS CANCELLED... The majority of snow has ended. Minor impacts due to wind and light snow may continue through the rest of the day, but conditions should gradually improve. $$ WYZ015-190000- /O.CON.KRIW.WS.W.0005.000000T0000Z-260519T0000Z/ Wind River Mountains East- 1246 PM MDT Mon May 18 2026 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Heavy snow. Additional snow accumulations up to 2 inches, with 4 to 6 inches at the highest elevations. Winds gusting as high as 40 mph. * WHERE...Wind River Mountains East. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel will be very difficult, especially over South Pass. PRECAUTIONARY/PREPAREDNESS ACTIONS... If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ018-190000- /O.CON.KRIW.WS.W.0005.000000T0000Z-260519T0000Z/ Lander Foothills- Including the cities of Lander 1246 PM MDT Mon May 18 2026 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Snow expected. Additional snow accumulations up to 2 inches. * WHERE...Lander Foothills. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel could be difficult. Heavy snow could break tree limbs as many trees have leafed out. PRECAUTIONARY/PREPAREDNESS ACTIONS... If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ019-190000- /O.CON.KRIW.WS.W.0005.000000T0000Z-260519T0000Z/ Green Mountains and Rattlesnake Range- Including the cities of Jeffrey City 1246 PM MDT Mon May 18 2026 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Heavy snow. Additional snow accumulations 1 to 4 inches. Winds gusting as high as 50 mph. * WHERE...Green Mountains and Rattlesnake Range. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel will be difficult due to a combination of wind and falling snow. PRECAUTIONARY/PREPAREDNESS ACTIONS... If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ020-190000- /O.CON.KRIW.WS.W.0005.000000T0000Z-260519T0000Z/ Natrona County Lower Elevations- Including the cities of Casper 1246 PM MDT Mon May 18 2026 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Heavy snow expected. Total snow accumulations between 1 and 3 inches. Areas of higher amounts up to 4 inches between Hiland and Casper and for the south side of Casper. Winds gusting as highas 40 mph. * WHERE...Natrona County Lower Elevations. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel will be difficult, especially along US Highway 20/26 between Hiland and Casper. Heavy snow could break tree limbs as many trees have leafed out. PRECAUTIONARY/PREPAREDNESS ACTIONS... If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ022-190000- /O.CON.KRIW.WS.W.0005.000000T0000Z-260519T0000Z/ Casper Mountain- 1246 PM MDT Mon May 18 2026 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Heavy snow possible. Additional snow accumulations between 3 and 6 inches possible. Winds could gust as high as 40 mph. * WHERE...Casper Mountain. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel will be very difficult. Areas of blowing snow could significantly reduce visibility. Heavy snow could break tree limbs as many trees have leafed out. PRECAUTIONARY/PREPAREDNESS ACTIONS... If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ030-190000- /O.CON.KRIW.WS.W.0005.000000T0000Z-260519T0000Z/ East Sweetwater County- Including the cities of Wamsutter 1246 PM MDT Mon May 18 2026 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Heavy snow expected. Additional snow accumulations between 1 and 3 inches. Lower amounts up to 1 inch in the Rock Springs area. Winds gusting as high as 60 mph. * WHERE...East Sweetwater County. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel will be very difficult, especially along Interstate 80 due to the crosswind component. PRECAUTIONARY/PREPAREDNESS ACTIONS... If you must travel, keep an extra flashlight, food, and water in your vehicle in case of an emergency. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ014-190000- /O.CON.KRIW.WW.Y.0019.000000T0000Z-260519T0000Z/ Wind River Mountains West- 1246 PM MDT Mon May 18 2026 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Snow expected. Additional snow accumulations between 3 and 5 inches. Winds gusting as high as 60 mph. * WHERE...Wind River Mountains West. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel could be difficult, especially along South Pass. The hazardous conditions could impact the Monday evening commute. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ026-190000- /O.CON.KRIW.WW.Y.0019.000000T0000Z-260519T0000Z/ Upper Green River Basin- Including the cities of Big Piney, La Barge, and Farson 1246 PM MDT Mon May 18 2026 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Snow expected. Total snow accumulations up to 2 inches. Winds gusting as high as 45 mph. * WHERE...Upper Green River Basin. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel could be difficult due to a combination of wind and falling snow. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ027-190000- /O.CON.KRIW.WW.Y.0019.000000T0000Z-260519T0000Z/ South Lincoln County- Including the cities of Cokeville and Kemmerer 1246 PM MDT Mon May 18 2026 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Snow expected. Additional snow accumulations up to 1 inch. Winds gusting as high as 40 mph. * WHERE...South Lincoln County. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel could be difficult due to a combination of wind and falling snow. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ WYZ028-029-190000- /O.CON.KRIW.WW.Y.0019.000000T0000Z-260519T0000Z/ Rock Springs and Green River-Flaming Gorge- Including the cities of Green River and Rock Springs 1246 PM MDT Mon May 18 2026 ...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING... * WHAT...Snow expected. Additional snow accumulations up to 1 inch. Winds gusting as high as 55 mph. * WHERE...Flaming Gorge and Rock Springs and Green River. * WHEN...Until 6 PM MDT this evening. * IMPACTS...Travel could be difficult, especially along Interstate 80. The hazardous conditions could impact the Monday evening commute. PRECAUTIONARY/PREPAREDNESS ACTIONS... Slow down and use caution while traveling. For graphical depictions of the snowfall forecast, including the official NWS forecast, high end amounts, and low end amounts, visit https://weather.gov/riw/winter . For winter road conditions from the Wyoming Department of Transportation, visit https://wyoroad.info . && $$ For more information from the National Weather Service, visit https://weather.gov/riw/ . Wittmann