Localized high wind occurred in eastern Natrona County. Wind gusts at Hat Six Road to the east of Casper peaked at 58 mph.
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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.
Localized high wind occurred in eastern Natrona County. Wind gusts at Hat Six Road to the east of Casper peaked at 58 mph.
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, 11:00 AM MST, 52 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 1100 AM MST Sat Jan 2 2021 .SHORT TERM...(Today through Sunday) Issued at 400 AM MST Sat Jan 2 2021 Clouds have moved into most of the region as a fast moving weather system is passing by today. Light snow is occurring as of 1030Z in the far west mountains with the far west valleys soon to see a brief shot of snow. Windy in the central wind corridor as well as parts of northwest WY. Natrona county has a High Wind Warning until noon and will let it ride as the pressure gradient may tighten some this morning as the weather system passes. Periods of light snow in the western mountains today and scattered snow in the far west valleys, as this weather system passes through today. Light accumulations are expected. The northern Bighorn mountains should get a quick shot of snow later this morning into the afternoon with light amounts. Otherwise, dry today with windy areas in the central and parts of the northwest. High temperatures today will be in the 30s to lower 40s east of the divide with 20s to around 30 west of the divide. Light snow will linger over the higher mountain peaks of the west tonight with light accumulations. Parts of the far west valleys might see a dusting tonight. Otherwise, dry weather is forecast. Windy to very windy in the Cody Foothills tonight. Will keep the High Wind Watch and will let the day shift get another look at the potential. Remaining windy in the central wind corridor tonight. Low temperatures will be in the teens and 20s with single digits in some of the colder valleys where the wind will not impact low temps. Sunday will see another fast moving weather system move through the northern Rockies. It will bring more snow to the western mountains and far west valleys, with amounts below advisory criteria for the most part. Windy for the south, central, and parts of the northwest. Wind gusts over 50 mph will occur and a few places may reach high wind criteria. Will hold off on any highlight for Sunday in the central zones and see how new model runs handle things. High temperatures will be in the 30s and 40s east of the divide with 20s to lower 30s in the west. .LONG TERM...(Sunday night through Friday) Issued at 400 AM 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. Models show mild air for much of the state on Tuesday, so it is possible that the precipitation may be in the form of rain for the Wind River and the Bighorn Basin. 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 18Z TAFS through 18Z Sunday) Issued at 1100 AM MST Sat Jan 2 2021 West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals Lingering snow showers will bring occasional MVFR conditions in the western mountains and valleys through the afternoon. Most impacts will be seen at KJAC as KPNA and KBPI will see more extended breaks in activity. Expect frequent mountain obscurations. It will remain dry at KRKS, with southwest winds expected to increase a bit more this afternoon. Conditions will slowly improve ceiling wise to VFR conditions after 00Z at the TAF sites. KJAC will continue to see VCSH after 05Z, with MVFR conditions possible overnight. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals VFR conditions will continue through the period. The main aviation hazard will be gusty southwest wind at KCPR, which will see gusts of 35 to 40 knots today. Winds will stay up at KCOD and KCPR overnight and through the end of the forecast period. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued AT 400 AM MST Sat Jan 2 2021 Expect light snow in the western mountains today and tonight. Scattered light snow in the far west valleys will occur. The northern Bighorn mountains will see a quick shot of light snow late this morning into the afternoon. Otherwise, it will dry elsewhere today and tonight. Windy weather will be common in the central zones and in northwest WY today and tonight. Smoke dispersal today will be poor in the valleys with fair in the windy locations. Sunday will see more snow for the western mountains and far west valleys. Mostly dry elsewhere Sunday. Windy weather will continue for the central zones and parts of the northwest. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning until noon MST today for WYZ020. High Wind Watch from 5 PM MST Today through Sunday morning for WYZ003. && SHORT TERM...AR LONG TERM...Clayton AVIATION...Hulme FIRE WEATHER...AR
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.
Special Weather Statement National Weather Service Riverton WY 1102 AM MST Sat Jan 2 2021 WYZ001-012-013-023-024-031315- Yellowstone National Park-Teton and Gros Ventre Mountains- Jackson Hole-Star Valley-Salt River and Wyoming Ranges- Including the cities of Lake, Mammoth, Old Faithful, Jackson, Afton, Alpine, Star Valley Ranch, and Thayne 1102 AM MST Sat Jan 2 2021 ...Another Round of Snow for Far Western Wyoming late Tonight and Sunday... This is a special weather statement from the National Weather Service in Riverton. * WHAT...Light to occasionally moderate snow. * WHERE...Far western Wyoming including Yellowstone, Jackson Hole, Star Valley and surrounding mountains. * WHEN...Late tonight through Sunday night. * ADDITIONAL DETAILS...The heaviest snow will occur during the day Sunday. Total snowfall is expected to be 1 to 3 inches in the lower elevations, and 3 to 5 inches in the surrounding mountains. The Teton Range should see 4 to 8 inches of snow with locally higher amounts on west facing slopes. * IMPACTS...Winter driving conditions. Visibility in bursts of heavier snow along with blowing snow will be under a quarter mile. 21
Special Weather Statement National Weather Service Riverton WY 1129 AM MST Sat Jan 2 2021 WYZ020-030000- Natrona County Lower Elevations- Including the city of Casper 1129 AM MST Sat Jan 2 2021 ...Strong Winds continue this Afternoon across Natrona County... This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...South to southwest winds of 25 to 35 mph with gusts 40 to 50 mph. * WHERE...Natrona County lower elevations. * WHEN...This afternoon. * ADDITIONAL DETAILS...Please keep two hands on your steering wheel in case of a sudden, strong wind gust. 21
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
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: 931698.