A cold front swept across Wyoming on January third. Ahead of the front, high winds occurred in some of the favored areas in Natrona and Johnson Counties.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS RIW wrote it up.
A cold front swept across Wyoming on January third. Ahead of the front, high winds occurred in some of the favored areas in Natrona and Johnson Counties. Winds gusted to 72 mph near Clark, Wyoming and 62 mph to the south of Casper, Wyoming along Wyoming Boulevard.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Riverton, WY wrote its last area forecast discussion before the first event at Jan 2, 10:21 PM MST, 4 hours 54 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 1021 PM MST Sat Jan 2 2021 .SHORT TERM...(This evening through Sunday night) Issued at 145 PM MST Sat Jan 2 2021 Water vapor imagery shows the trough pulling across the Rockies early this afternoon. Also satellite imagery shows a compact circulation trying to develop over central Wyoming. The bulk of the accumulating snow over the west should come to an end shortly as the trough continues to pull away. However very light snow/flurries over the far west will occur for much the night. Farther east, the compact circulation could allow for some snow showers this afternoon into early this evening over the far east. The limiting factor will be the present dry subcloud layer. The next storm system is approaching southern British Columbia. This system will push into the Pacific Northwest tonight, and then quickly across the extreme northern Rockies along the U.S./Canada border. This system will result in a westerly moist upglide pattern into the far west resulting in light to moderate snowfall Sunday into Sunday evening. Snow amounts continue to be borderline advisory amounts, but in middle of winter have leaned toward a special weather statement for now. Also mentioned some blowing snow as winds will be overall stronger than today especially in the lower elevations. The overnight shift can give one last look to decide if an advisory is necessary. East of the Divide, dry conditions are expected with wind being the main concern. Tonight, the Cody Foothills look to have a good potential for marginal high wind as strong winds aloft, subsidence, combine with a decent temp gradient from Yellowstone to the Foothills. Have upgraded the Cody Foothills to a warning tonight into Sunday morning. A tight pressure gradient and strong flow aloft could result in high wind across the lower elevations of Natrona County during the day Sunday. A high wind watch is in effect for that area. Also strong wind is expected in the Dubois area, SE Fremont County, and Sweetwater County. Upper level ridging begins to build into the area Sunday night. Although some light snow/flurries are expected to occur over the far west, little additional accumulation is expected Sunday night. .LONG TERM...(Monday through Saturday) Issued at 145 PM MST Sat Jan 2 2021 Unsettled weather looks to be the story for the long-term period. Starting with the overnight Sunday/Monday morning, the axis of the trough looks to be just east of the CWA. High winds are still looking quite likely with a tight gradient across the state. Moving towards the first part of the day Monday, the snow is expected to diminish over the west as the trough moves further to the east and ridging builds in for the area. The axis of this ridge looks to move over the area during the day Monday, but upslope flow may still keep snow over the Tetons and the west on the backside of the axis. Any break in the action may be short- lived as the next system moves in from the west late on Monday and into Monday night. Models show the trough axis and accompanying precipitation covering much of the area during the day Tuesday. Snowfall may occur east of the Divide with this system, but models vary widely as to the coverage of the precipitation with this feature. GFS shows mild air for much of the state on Tuesday, which would make it possible that the precipitation may be in the form of rain for the Wind River and the Bighorn Basin. However NAM has H7 temps of -10 moving in quickly Tuesday morning. Later shifts will have to look into this to see where model guidance is leading. It looks like snow moves out of the area Wednesday with ridging over the state. There is very low confidence for the end of the period, but the ECMWF brings another batch of snowfall towards the state for Wednesday night into Thursday, whereas the Canadian shows the ridge still over the area. Another trough is projected to move through the area moving towards Friday. && .AVIATION...(For the 06Z TAFS through 06Z Monday) Issued at 1016 PM MST Sat Jan 2 2021 -SN continues to overspread the KJAC region this evening, and will continue for most of the next 24 hours, with low cigs and lowered vis expected. The snowfall is expected to expand overnight into tomorrow morning, with some -shsn reaching KBPI and KPNA during the day Sunday. Snow at these locations will come to an end by Sunday evening, with high clouds remaining. Remaining sites will see VFR conditions through the next 24 hours. Breezy conditions expected for KRKS/KCPR/KCOD during the day, with occasional gusts to 30kts expected. && .FIRE WEATHER... Issued AT 145 PM MST Sat Jan 2 2021 Periods of light to occasionally moderate snow is expected over the far west next couple of days. The heaviest snow will occur during the day Sunday. Areas east of the Divide and over the south will be mainly dry, but breezy. Despite breezy to windy conditions, most locations will have poor to fair smoke dispersal. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Watch from 6 AM MST Sunday through Sunday afternoon for WYZ020. High Wind Warning until noon MST Sunday for WYZ003. && SHORT TERM...Murrell LONG TERM...Hulme/Clayton AVIATION...Straub FIRE WEATHER...Murrell
Hazardous Weather Outlook National Weather Service Riverton WY 1130 AM MST Sat Jan 2 2021 WYZ001>020-022>030-031300- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Big Horn Basin-Southwest Big Horn Basin- Southeast Big Horn Basin-Owl Creek and Bridger Mountains- Bighorn Mountains West-Bighorn Mountains Southeast- Northeast Johnson County-Southeast Johnson County- Teton and Gros Ventre Mountains-Jackson Hole- Wind River Mountains West-Wind River Mountains East- Upper Wind River Basin-Wind River Basin-Lander Foothills- Green Mountains and Rattlesnake Range- Natrona County Lower Elevations-Casper Mountain-Star Valley- Salt River and Wyoming Ranges-Upper Green River Basin Foothills- Upper Green River Basin-South Lincoln County- Rock Springs and Green River-Flaming Gorge-East Sweetwater County- 1130 AM MST Sat Jan 2 2021 ...High Wind Watch for Natrona County Sunday... ...High Wind Warning for the Cody Foothills Tonight through Sunday Morning... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Light snow over the far west is expected to taper off by late this afternoon into early evening. High wind is expected tonight across the Cody Foothills. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Sunday...Light to moderate snow over the far west. Windy to very windy conditions in central Wyoming, and parts of northwest Wyoming. The strongest winds are expected in the Cody Foothills and in Natrona County. Late Monday night and Tuesday...Snow is likely in the west. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today or tonight.
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
A 72 mph wind gust was recorded 8 miles south-southwest of Clark.
A maximum wind gust of 62 mph was recorded to the south of Casper along Wyoming Boulevard.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2021Every state in 2021This day in weather historyWarnings in Wyoming, January 2021
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 931714, 931715.