A cold front moved across Wyoming and brought another round of high wind to northern Wyoming. The highest wind gusts reported were 66 mph at the Greybull and Johnson County airports.
Every event with a place to put it; 3 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 moved across Wyoming and brought another round of high wind to northern Wyoming. The highest wind gusts reported were 66 mph at the Greybull and Johnson County airports.
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 Apr 10, 1:53 PM MST, 1 hour 28 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 253 PM MDT Sat Apr 10 2021 .SHORT TERM...This evening through Sunday night Issued at 250 PM MDT Sat Apr 10 2021 A trough will pull across the northern Rockies into northern High Plains tonight. The associated strong cold front will pull into north/northwest Wyoming between 7 and 9 PM, and sweep across much of the area by 3 AM. Three-hourly pressure rises between 10 and 14 mb are expected across the north in wake of this cold front. This set up will likely produce some high wind across northern Johnson and portions of Big Horn County with confidence higher across N. Johnson. Have upgraded the high wind watch to a warning. Some precipitation is expected along and behind the cold front mainly along and east of the Divide as well as northwest Wyoming generally from Jackson northward. The best chances of precipitation will be across the north between 9 PM and 3 AM associated with mid-level diffluence and dynamics from a left- exit region of an upper jet pulling across the area. Most if not all of the precipitation will be snow with the strong cold air advection in wake of the front. Snow amounts are expected to be mainly light with a few inches expected across the northern mountains and up to an inch in the lower elevations. The snow is expected to end in most locations from northwest to southeast late tonight into Sunday morning as the trough pulls away from the area. However a relatively moist northwest flow will continue to result in isolated to locally scattered snow showers mainly across the northern mountains into adjacent foothills Sunday into Sunday night. Models are hinting at the potential for banding of snow in typical northwest flow areas such as off the southern Bighorn Mts. into southern Johnson County Sunday afternoon and evening. Overall winds will be much weaker Sunday than what is occurring this afternoon and what is expected in wake of the cold front tonight. The main exception is strong winds will continue across northern Johnson County on Sunday, but are not expected to be high wind. These winds are expected to decrease around sunset. .LONG TERM...Monday through Saturday Issued at 250 PM MDT Sat Apr 10 2021 Monday will be mainly dry over most of the area, with some lingering mountain showers in the northwest flow. Models have become a bit of a mess Monday night. GFS and Canadian still show the cut-off low forming in the Pacific Northwest, while Euro and NAM are moving towards a elongated trough to our north. This could indicate less activity in the area for Tuesday if the energy remains across Montana. We will keep with the trend of widespread lower PoPs for Tuesday. By Tuesday night models come more in-line with a cut-off low over the Intermountain West. Precip should begin to increase from south to north at this point. Models again deviate at this point with some keeping the low over the Intermountain West and drifting a bit north, while the GFS brings it east across Wyoming. Regardless, Wednesday and Thursday still have the best possibility for precipitation across the state. H7 temps look to be cold enough for snow in most areas, but there may be enough warming during the day to get some rain or rain/snow mix in the lower elevations. This will be most likely in the south and portions of Natrona County. Temperatures during the period look to stay well below normal through Friday with highs in the 30s and 40s. Friday and Saturday are a toss up as models have the low moving in many different solutions. Overall, precipitaion should be on the decline and temperatures will be on the increase once again heading into the weekend. && .AVIATION...For the 18Z TAFS through 18Z Sunday Issued at 1120 AM MDT Sat Apr 10 2021 East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals Mainly SKC with windy westerly wind at area terminals this afternoon. A strong cold front will pull into northern Wyoming between 01Z and 03Z, and sweep southward to the Continental Divide by around 08Z. In wake of the cold front, strong northerly winds will occur with lowering ceilings and a chance of snow. KCOD looks to have the best shot of snow with a period of IFR/MVFR conditions generally between 04Z and 08Z. MVFR ceilings are expected to develop at KCPR around 09Z, with a chance of snow. The other terminals are expected to remain VFR except perhaps a brief snow shower. Will have VCSH in KWRL, but keep the mention out of KRIW and KLND as chances of snow showers looks to be minimal farther south. Improving conditions will occur late tonight into Sunday morning from north to south with decreasing cloudiness along with chances of snow diminishing. However, there will remain chances of isolated snow showers along the northern mountains into the adjacent foothills through the day which could impact KCOD Sunday afternoon. The wind will decrease, but remain breezy in most locations with the strongest winds continuing over N. Johnson County. West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals Mainly SKC with windy westerly wind at area terminals except more southerly at KJAC this afternoon. A cold front will push east across the area generally between 03Z and 09Z. This will generally be a dry cold front with an outside chance of snow showers from around KJAC northward. Will keep the mention of snow showers out of the KJAC for now, but will have ceilings near MVFR. Any low clouds should dissipate by mid-late morning. The windy westerly winds look to decrease a bit in most locations this evening, before increasing with the frontal passage. The strong winds in wake of this cold front are expected to weaken Sunday morning. 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 250 PM MDT Sat Apr 10 2021 Elevated fire conditions will continue in the southwest and south through sunset. A strong cold front moves through the area tonight. Snow showers will occur in the northwest and northern mountains tonight with scattered snow showers in the lower elevations of the north. Scattered snow showers will be possible in the central zones late tonight into early Sunday morning. Strong to high winds over the north tonight and through the day Sunday. Sunday will be dry for most places with critical RHs in the southwest. Isolated snow showers are possible over the northern mountains Sunday. Smoke dispersal Sunday afternoon will be fair in far west, and very good elsewhere. && .RIW WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 7 PM this evening to 4 AM MDT Sunday for WYZ004-010. && SHORT TERM...Murrell LONG TERM...Hulme AVIATION...Murrell FIRE WEATHER...Hulme
Hazardous Weather Outlook National Weather Service Riverton WY 1157 AM MDT Sat Apr 10 2021 WYZ001>020-022>030-111200- 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- 1157 AM MDT Sat Apr 10 2021 ...A High Wind Warning is in effect Tonight for Northern Johnson County and Big Horn County... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Elevated fire conditions are expected over parts of central and southern Wyoming this afternoon through sunset. Tonight...A strong cold front will move through the area tonight with strong northerly winds in wake of the front. The strongest winds are expected across northern Johnson and Big Horn County. Please see the high wind warning for more details. Snow showers will occur in the northwest mountains and the Bighorn mountains tonight. A chance of snow showers will occur at the lower elevations, east of the continental divide tonight, after the cold front passage. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Sunday...Continued windy in northern Johnson county with gusts over 40 mph, decreasing toward evening. Tuesday night...A chance of snow in the south and central. Wednesday...A chance of snow most areas. Mixed rain and snow for parts of the south. Thursday...A chance of snow for most places. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions, according to standard operating procedures.
Special Weather Statement National Weather Service Riverton WY 205 PM MDT Sat Apr 10 2021 WYZ016-111000- Upper Wind River Basin- Including the city of Dubois 205 PM MDT Sat Apr 10 2021 ...Strong Winds through Tonight... This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...West to northwest winds 25 to 35 mph with a few gusts between 50 and 55 mph. * WHERE...Upper Wind River Basin including Dubois. * WHEN...Now through late tonight. * ADDITIONAL DETAILS...There could control issues especially for light and high profile vehicles, including campers and tractor trailers. WYZ003-111000- Cody Foothills- Including the cities of Clark, Cody, and Meeteetse 205 PM MDT Sat Apr 10 2021 ...Strong Cold Front Tonight with some Snow... This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...A cold front will sweep south across the Cody Foothills this evening with north winds between 20 and 30 mph with gusts to 45 mph. Snow showers are also expected in wake of the cold front with up to an inch of accumulation. * WHERE...Cody Foothills. * WHEN...Tonight. * ADDITIONAL DETAILS...Snow showers could lead to low visibility and slick roads at times. WYZ011-111000- Southeast Johnson County- Including the city of Kaycee 205 PM MDT Sat Apr 10 2021 ...Strong Cold Front Tonight with some Snow... This is a special weather statement from the National Weather Service Office in Riverton. * WHAT...A cold front will sweep south across southern Johnson County late this evening with north winds between 20 and 30 mph with gusts to 45 mph. Snow showers are also expected in wake of the cold front with up to an inch of accumulation. * WHERE...southern Johnson County. * WHEN...Tonight. * ADDITIONAL DETAILS...Snow showers could lead to low visibility and slick roads at times. 21
The national radar mosaic for the moment the first event began.
3 high wind. Local standard time, as filed.
A 59 mph wind gust was reported at the Natrona County airport.
High winds were reported in the Big Horn Basin. The highest wind gust reported was 66 mph at the South Big Horn County airport in Greybull, Wyoming.
High wind was reported through much of northern Johnson County. The highest wind gust reported was 66 mph at the Johnson County airport in Buffalo, Wyoming.
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, April 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: 953551, 953549, 953550.