Brief period of strong winds occurred around midday on the 9th of October across southeast Wyoming including the Arlington gap area along Interstate 80 and the city of Cheyenne.
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 CYS wrote it up.
Brief period of strong winds occurred around midday on the 9th of October across southeast Wyoming including the Arlington gap area along Interstate 80 and the city of Cheyenne.
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 Oct 9, 10:49 AM MST, 1 hour 49 minutes earlier.
Area Forecast Discussion National Weather Service Cheyenne WY 1149 AM MDT Sat Oct 9 2021 .SHORT TERM...(Today through Monday) Issued at 330 AM MDT Sat Oct 9 2021 Current KCYS radar loop shows shower activity ending across east central Wyoming and the northern Nebraska panhandle early this morning, while another round is getting going further west across Carbon and Albany counties. Weak surface cold front is hard to pick out on surface charts and obs, and believe the front will dissipate or weaken even further today as the southern branch of the upper level trough splits to the south near the four corners region. The northern disturbance is expected to accelerate eastward later today into the Dakotas. Expect some slightly cooler air to push southward into the region though the day behind the northern upper level trough/disturbance, which will keep high temperatures a few degrees cooler compared to the last 2 days with highs in the mid 50s for the lower elevations of Carbon and Albany counties. Daytime temperatures will be mild along and east of the Interstate 25 corridor with readings peaking in the mid 60s to mid 70s, warmest further south and east across the southern Nebraska panhandle. Precipitation potential and coverage is going to be tricky today, but believe the best chance for showers and a few thunderstorms will be further north across Niobrara and Converse counties, and into the far northern NE panhandle, and across Carbon county into this evening as split flow develops by this evening. Expect precipitation to come to an end after midnight tonight as both disturbances move away from the forecast area. 3 to 6 inches of snow is still possible across the highest mountains peaks through tonight, but winter weather headlines are not expected at this time. Gusty to locally strong winds are possible today, especially early this morning, behind the upper level trough which will move into the Dakotas later today. So far, wind prone areas have shown gusts up to 37 mph. Models show 700mb to 800mb winds of around 40 to 45 knots with very good subsidence in and near the wind prone areas. The best subsidence even makes it to just west of Cheyenne later this morning. Will need to keep an eye on winds today, but winds have initialized below MOS and model consensus so far, likely due to an elevated temperatures inversion above 700 mb. Will hold off on any High Wind headlines due to low confidence, but may need a Special Weather Statement to address gusts over 45 MPH if winds continue to increase through sunrise. Drier weather is expected on Sunday and Monday with cooler temperatures remaining over the area as a ridge axis develops and amplifies across the northern Rockies. Due to the lack of cloud cover, increased temperatures a few degrees along and west of the I-25 corridor for Sunday afternoon. Kept temperatures in the 60s further east due to north/northwest flow. Attention then shifts to the west on Monday as a potent upper level trough and strong cold front digs south across the Great Basin region through the day. This system will be the primary weather concern for the Tuesday and Wednesday time period. .LONG TERM...(Monday night - Friday) Issued at 305 AM MDT Sat Oct 9 2021 Main story for next week will be the Pacific trough that will dig into the Great Basin Monday night bringing colder weather, precipitation, and strong winds into the CWA Tuesday and Wednesday. Plenty of uncertainty remains with this system, but GEFS members are showing considerably less spread compared to 48 hours ago. Low track with latest guidance is located farther north which could limit precipitation amount for extreme southeast Wyoming and keeping much of the Nebraska Panhandle warmer and drier with predominantly southerly flow. Best chances for snowfall will be west of the Laramie Range with areas most likely to receive notable snowfall being in the Snowy and Sierra Madre Mountains. Snow levels will drop to around 5-6 kft Tuesday night as 700mb temps drop to around -5C. Along and just east of the Laramie Range, snow is still very likely mixed in with rain but will have difficulty accumulating through Wednesday morning. One area to watch based on the current track will be the North Laramie Range with a good upslope component out of the north that could elevate local snowfall amounts between Douglas and Casper. A major limiting factor with this system will be its duration over the region. A trailing system enters the PacNW that looks to quickly push this system off to the north and east by early afternoon Wednesday. Therefore, may be difficult to reach significant accumulations over a 12-18 hour period while also attempting to overcome warm surface/ground temperatures. Regardless, this anomalously strong trough will usher in much colder air to the region and likely result in temperatures reaching the freezing mark out over the Nebraska Panhandle before week's end. Strong winds will also sweep through in the system's wake with latest model trends tightening pressure gradient even more. Strong subsidence and 60+ kts around 750mb Wednesday morning could result in high wind conditions not only for SE WY wind prone areas, but also the southern NE Panhandle. && .AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon) Issued at 1128 AM MDT Sat Oct 9 2021 The big headline for today is the gusty winds. All terminals are expected to see gusty winds as a weak front and some shower activity moves through the region. Terminals in Wyoming could see gusts from 35 to 40kts with winds out of the southwest, shifting to northwest as the front passes. Terminals in the Nebraska Panhandle could see gusts up to 35kts out of the northwest. Winds should calm down at KRWL and KLAR sometime this evening. Remaining terminals could see gusty winds into the overnight hours. There is also a threat for showers this afternoon up until about midnight, mainly for KRWL, KLAR and KCDR. Guidance hints at some MFRV conditions for KRWL in the form of low ceilings with some of those showers. && .FIRE WEATHER... Issued at 254 AM MDT Sat Oct 9 2021 Minimal fire weather concerns this weekend through next week as a series of cold fronts gradually bring colder air to the region as well as higher humidities and chances for precipitation, mainly in the form of snow above 7000 feet. Very windy conditions are expected today across most of southeast Wyoming and portions of western Nebraska with gusts around 50 to 55 mph possible. After a dry Monday, widespread precipitation is expected for Tuesday and Wednesday. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && SHORT TERM...TJT LONG TERM...MB AVIATION...SF FIRE WEATHER...TJT
Hazardous Weather Outlook National Weather Service Cheyenne WY 444 AM MDT Sat Oct 9 2021 WYZ101>119-101045- Converse County Lower Elevations-Niobrara County- North Laramie Range-Ferris/Seminoe/Shirley Mountains- Shirley Basin-Central Laramie Range and Southwest Platte County- East Platte County-Goshen County-Central Carbon County- North Snowy Range Foothills-Southwest Carbon County- Sierra Madre Range-Upper North Platte River Basin-Snowy Range- Laramie Valley-South Laramie Range-South Laramie Range Foothills- Central Laramie County-East Laramie County- 444 AM MDT Sat Oct 9 2021 This hazardous weather outlook is for east central Wyoming and southeast Wyoming. .DAY ONE...TODAY AND TONIGHT Windy conditions are expected to develop today across all of southeast Wyoming. Sustained west to northwest winds of 20 to 30 MPH with gusts up to 45 MPH are expected. Wind prone areas will likely see locally higher gusts above 50 MPH at times through this afternoon. Otherwise, temperatures will trend cooler this weekend with a slight chance for thunderstorms today. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY Lots of uncertainty still remains with next week's potential storm system. The first snowfall of the season is still possible above elevations of 5000 feet, but amounts and intensity are unknown at this time. Please monitor the latest forecasts and statements for possible travel impacts. .Spotter information statement... Spotter activation will not be required. NEZ002-003-019>021-054-055-095-096-101045- Dawes County-Box Butte County-Scotts Bluff County-Banner County- Morrill County-Kimball County-Cheyenne County- Northern Sioux County-Southern Sioux County- 444 AM MDT Sat Oct 9 2021 This hazardous weather outlook is for portions of panhandle Nebraska. .DAY ONE...TODAY AND TONIGHT No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY There is increasing confidence for a strong storm system to develop across Colorado and move northeast across the region Tuesday and Wednesday of next week. Strong winds, widespread rainfall, and even some snow is possible Tuesday through Wednesday morning. .Spotter information statement... Spotter activation will not be needed.
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
WYDOT mesonet station KARL - Arlington along Interstate 80 measured wind gust.
ASOS station KCYS - Cheyenne Airport measured wind gust as peak wind.
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, October 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: 979280, 979279.