Period of high winds were measured along the Interstate 80 corridor between Rawlins and Cheyenne. Several Wyoming Department of Transportation sensors along the route measured wind gusts into the upper 60 mph range.
Every event with a place to put it; 4 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 CYS wrote it up.
Period of high winds were measured along the Interstate 80 corridor between Rawlins and Cheyenne. Several Wyoming Department of Transportation sensors along the route measured wind gusts into the upper 60 mph range.
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 Cheyenne, WY wrote its last area forecast discussion before the first event at Jan 17, 4:45 AM MST, 4 hours 47 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY Issued by National Weather Service Riverton WY 445 AM MST Sun Jan 17 2021 .SHORT TERM...Today through Tuesday Issued at 1202 AM MST Sun Jan 17 2021 The northwest flow continues over the area this morning, with mid to high clouds streaming within the flow. Isolated patches of low clouds have also developed. Winds will begin to increase by this afternoon, as a cold front approaches the area from MT. Strong winds will be possible over the wind-prone locations, as winds turn more westerly ahead of the front and the gradient tightens. Light snow will begin over the mountains by mid to late afternoon, with snow showers across most of the forecast area after sunset. However, little accumulation is expected. A Winter Weather Advisory remains in effect for snow and blowing snow across the Sierra Madre and Snowy Mountain Ranges, as well as the I-80 corridor, Arlington to Elk Mountain, between Rawlins and Laramie. These showers will continue through the overnight hours, as the cold front rapidly moves through and clears the state before midnight. This is the period of most concern, as stated in the Advisory, as the heaviest snow showers will combine with wind gusts to 50 mph at times, and chances for snow squall development. Any travel between this time will be effected. Gusty northwest winds will continue across the area Monday, with highs 5 to 10 degrees colder, in the wake of the cold front. Snow showers will gradually taper off by the afternoon, with clearing skies Monday night. Dry and tranquil conditions will be in place Tuesday. .LONG TERM...Tuesday night through Saturday Issued at 1202 AM MST Sun Jan 17 2021 High winds are possible starting Tuesday night across Wyoming wind prone areas with westerly flow dominating the region. Lower confidence for high winds in the Nebraska Panhandle thus typical breezy but elevated winds are expected. The wind event is currently anticipated to last around 24 hours. The timing and severity will become more clear as we approach Tuesday. A short ridge pattern will begin Wednesday night into Thursday, along with average temperatures and mostly clear skies. The GFS and ECMWF seem to agree on a widespread impactful event of snowfall Friday into Saturday, but it is too far out to have confidence in the level of impact for the event. && .AVIATION...For the 12Z TAFS through 12Z Monday Issued at 445 AM MST Sun Jan 17 2021 VFR conditions are expected through the daytime hours, with breezy west-northwest winds across much of the area. A clipper system moving into the region late today and tonight will bring snow showers to portions of southeast WY and the NE panhandle, especially the mountains, with areas of MVFR conditions developing. && .FIRE WEATHER... Cold with a few chances of light precipitation Sunday and Monday for low fire concerns. The driest period will be Tuesday through Thursday, as humidities drop into the upper 20s. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...TL (RIW Backup) LONG TERM...LK/MLH (RIW Backup) AVIATION...ST (UNR Backup) FIRE WEATHER...TL (RIW Backup)
Hazardous Weather Outlook National Weather Service Cheyenne WY Issued by National Weather Service Riverton WY 850 AM MST Sun Jan 17 2021 WYZ104-109-111-113-115-181215- Ferris/Seminoe/Shirley Mountains-Central Carbon County- Southwest Carbon County-Upper North Platte River Basin- Laramie Valley- 850 AM MST Sun Jan 17 2021 This hazardous weather outlook is for portions of south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Periods of light to moderate snow showers late this afternoon into tonight. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY Periods of light snow continue on Monday. .Spotter information statement... Spotter activation will not be needed. NEZ002-003-019>021-054-055-095-096-WYZ101-102-107-108-118-119- 181215- Dawes-Box Butte-Scotts Bluff County-Banner County-Morrill- Kimball County-Cheyenne-North Sioux-South Sioux- Converse County Lower Elevations-Niobrara County- East Platte County-Goshen County-Central Laramie County- East Laramie County- 850 AM MST Sun Jan 17 2021 This hazardous weather outlook is for portions of panhandle Nebraska...western Nebraska...east central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Periods of light snow late tonight into early Monday for areas east of the Laramie Range into Nebraska. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY Periods of light snow continue Monday. .Spotter information statement... Spotter activation will not be needed. WYZ106-116-117-181215- Central Laramie Range and Southwest Platte County- South Laramie Range-South Laramie Range Foothills- 850 AM MST Sun Jan 17 2021 This hazardous weather outlook is for portions of southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Periods of moderate to perhaps heavy snow showers late this afternoon into tonight with gusty winds especially this afternoon and evening. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY Periods of snow continue on Monday. .Spotter information statement... Spotter activation will not be needed. WYZ110-112-114-181215- North Snowy Range Foothills-Sierra Madre Range-Snowy Range- 850 AM MST Sun Jan 17 2021 ...Winter Weather Advisory from 11 AM Today until 5 PM Monday... This hazardous weather outlook is for portions of south central Wyoming. .DAY ONE...TODAY AND TONIGHT Periods of heavy snow, strong winds and blowing snow developing later this afternoon and lasting through tonight. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY Periods of moderate to heavy snow, blowing snow continue Monday. .Spotter information statement... Spotter are encouraged to report any snowfall amounts. WYZ103-105-181215- North Laramie Range-Shirley Basin- 850 AM MST Sun Jan 17 2021 This hazardous weather outlook is for portions of south central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Periods light to moderate snow possible late this afternoon into tonight along with gusty winds to 40 mph. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY Periods of mainly light snow on Monday. .Spotter information statement... Spotter activation will not be needed. 21
The national radar mosaic for the moment the first event began.
4 high wind. Local standard time, as filed.
Wyoming Department of Transportation sensor at Arlington measured the reported wind gust. Several other sensors along the interstate measured high winds as well during the period.
Union Pacific Railroad sensor EMKAYW located fourteen miles west-southwest of Cheyenne measured the reported wind gust.
Wyoming Department of Transportation sensor along Interstate 80 at Lone Tree or two miles west of Buford measured the reported wind gust.
Wyoming Department of Transportation sensor along Interstate 80 at Quealy Dome or fourteen miles northeast of Centennial measured the reported wind gust.
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: 930389, 930393, 930392, 930390.