518 AM MDT Tue Mar 12 2019 Wind River Mountains West-Wind River Mountains East- Upper Green River Basin-Rock Springs and Green River- Including the cities of La Barge, Big Piney, Farson, Rock Springs, and Green River 518 AM MDT Tue Mar 12 2019 .Areas of fog this morning... Patches of dense fog has developed this morning over Highway 28 between Farson and South Pass, US Highway 191 between Farson and Boulder, and over western portions of Sweetwater County near Little America. Visibilities of a half mile or less will be possible in these areas.