A shortwave moved across Wyoming and brought severe thunderstorms with strong wind gusts. The strongest storm moved across eastern Yellowstone Park.
Every event with a place to put it. 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 shortwave moved across Wyoming and brought severe thunderstorms with strong wind gusts. The strongest storm moved across eastern Yellowstone Park. An 82 mph wind gust was reported that blew down several trees. Heavy rain caused an avalanche that closed the East Entrance of Yellowstone Park for several hours. Other strong storms occurred in southern Wyoming where wind gusts of 66 mph were reported at the Sweetwater County Airport and 59 mph at the Big Piney Airport.
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 May 16, 3:52 AM MST, 5 hours 53 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 452 AM MDT Mon May 16 2022 .SHORT TERM...(Today through Tuesday) Issued at 355 AM MDT Mon May 16 2022 Today will be an unusually mild late-spring day, featuring strong ridging aloft, temperatures about 15 degrees above normal, as well as scattered afternoon showers and thunderstorms supported by a subtle shortwave moving through the ridge. Despite relatively light large scale winds, temperature-dew point spreads will be large (in the 40 to 50 degree range); therefore, precipitation falling into the low levels is likely to evaporate and cool the surrounding air, leading to strong sinking motion and gusts when hitting the ground, likely in the 45 to 55 mph range in the immediate vicinity of showers and thunderstorms. A few gusts could be higher, especially across Sweetwater County where dew points could be even lower. MUCAPE will be on the order of 300 to 600 J/kg for portions of the area, yet strong thunderstorms are unlikely due to limited shear for most of the region. Yellowstone could be the exception, with enough shear aloft to support a few stronger cells. Afternoon convection looks to develop around 1 PM MDT, moves eastward throughout the day, eventually decreasing in intensity and coverage around sunset. Fire danger will also be elevated this afternoon and evening, given low RHs combined with these gusty erratic winds from showers (see the Fire Weather section for more details). After sunset, cooler air will push southward for basins east of the Divide. Expect a shift to northerly winds in the Bighorn and Powder River Basin between sunset and 3 AM Tuesday. As this frontal feature moves through, brief gusts of 40 to 50 mph are likely. Despite cold air advection overnight, Tuesday remains near to slightly above normal temperature-wise. Another weak vorticity maxima will spark additional scattered showers and thunderstorms. The slightly cooler temperatures will suppress fire danger somewhat, but southwest and south central Wyoming basins remain fairly dry, with RHs in the upper teens to low 20 percent range. .LONG TERM...(Tuesday night through Sunday) Issued at 355 AM MDT Mon May 16 2022 Convection on Tuesday will slowly be ending during the evening hours with all areas dry by later Tuesday night. Flat ridging then moves across the state on Wednesday and brings a warm and dry day. However, flat ridging and a fast moving pattern usually means windy conditions and Wednesday will be no exception. Mid level winds do not look very strong and the best jet energy remains to the west so high winds are not expected. The warm temperatures, windy conditions and low humidity will likely bring elevated fire weather to portions of the area for Wednesday afternoon though. A long wave trough then will move into the northern Rockies with two main pieces of energy and cold fronts with it. The first will begin to move into northern Wyoming later Wednesday night and into Thursday. During the day, at this point it appears the best jet dynamics will remain over northern Wyoming so the best chance of showers and embedded thunderstorms will be there. Further south, with the area in the right front quadrant of a potent 130 knot jet streak, it will be another windy day, especially in areas favored by northwest flow and cold advection like northern Johnson County, the Bighorn Basin and possibly the Wind River Basin. There is some uncertainty in timing though with the GFS about 6 to 12 hours faster than the European model. For now, we made few changes to continuity. Cooler air then moves in behind the front Thursday night before the second push arrives Friday. This one appears to have a better chance of more widespread showers. And with the cooler air in place, the chance of some mountain snow as well. As was stated by the previous shift, the main road problems would be at night as the strong mid May sun should melt any snow of roads during the day. Temperatures will average 20 degrees below normal across much of the area on this day. The deeper moisture will move away Saturday so showers should become much less numerous. However, with cyclonic curvature remaining over the area, lower elevation rain showers and higher elevation snow showers will continue to be around to some degree, mainly across northern Wyoming. The forecast then becomes more uncertain on Sunday with the arrival of the next system. The GFS, as usual, is faster with returning steadier precipitation to the west Sunday afternoon and spreading southward on Sunday night. Meanwhile, the European is much slower, keeping all areas dry through most of Sunday night and southern Wyoming dry through Monday as well. For now, we compromised and split the difference before there is more model agreement. && .AVIATION...12Z Issuance All terminals to be mainly VFR through the period. A shortwave Monday afternoon generates showers and isolated thunderstorms, initially over the northern and central mountains. The primary hazard will be gusty outflow wind. Brief MVFR vsby/cig may occur with any showers if they pass over a terminal. KCOD and KWRL may have the best chance for a thunderstorm late in the day, although outflow wind may reach several basin terminals. Except for the possible strong outflow wind, winds will be mainly light at all terminals through the period. Some shower activity should increase across the southwest terminals around 10Z Tuesday. 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 423 AM MDT Mon May 16 2022 Temperatures will run about 15 degrees above normal today. The warm temperatures combined with a relatively dry air mass (especially in the southwest and south central portion of the state where afternoon RHs range from 10 to 20 percent) will lead to elevated fire danger. Sustained winds will not be overly strong this afternoon, with westerly gusts of 20 to 30 mph. However, scattered showers and perhaps a few thunderstorms are are likely to be accompanied by strong erratic outflow winds, gusting 45 to 55 mph in the vicinity of showers. Have issued a Rangeland Fire Danger Statement for the lower elevations of Lincoln, Sublette, and Sweetwater counties, in effect for this afternoon and evening to cover this threat. Gusty north winds associated with a cold front will push southward east of the Divide after sunset through the early AM hours Tuesday. This feature will likely bring brief gusts of 40 to 50 mph to basins. Tuesday will feature slightly higher RHs and continued chances for showers and Tstorms. Wednesday RHs drop and winds increase as the ridge breaks down, leading to another day of elevated fire weather danger. A larger system with strong winds and widespread precipitation is forecast for Thursday and Friday. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...VandenBoogart LONG TERM...Hattings AVIATION...Hattings / Murrell FIRE WEATHER...VandenBoogart
Hazardous Weather Outlook National Weather Service Riverton WY 431 AM MDT Mon May 16 2022 WYZ001>020-022>030-171045- 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- 431 AM MDT Mon May 16 2022 This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight. Isolated to scattered afternoon showers and thunderstorms are likely, and could produce strong gusty outflow winds of 45 to 55 mph in the vicinity of the cells. A few strong thunderstorms are possible over Yellowstone. Fire danger will also be elevated in the southwest and south central portion of the state today due to dry air and gusty winds. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Tuesday...Isolated to scattered afternoon thunderstorms are possible. Wednesday...Elevated fire danger is likely due to dry air and gusty winds. Thursday and Friday...Widespread showers, snow, and strong winds are possible associated with the next larger weather system. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures.
The Billings radar (KBLX), 187 km away, was scanning. The volume nearest the first event began at 16:41 UTC.
3 thunderstorm wind. Local standard time, as filed.
An 82 mph wind gust was reported at the East Entrance of Yellowstone Park. Many trees were downed and power was knocked out. The road was closed until 7 pm due to an avalanche.
A 66 mph wind gust was reported at the Rock Springs Airport.
A 59 mph wind gust was reported at the Big Piney airport.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2022Every state in 2022This day in weather historyWarnings in Wyoming, May 2022
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: 1027963, 1027964, 1027965.