A shortwave moved across northern Wyoming and brought scattered showers and thunderstorms. Some storms contained high wind gusts.
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 northern Wyoming and brought scattered showers and thunderstorms. Some storms contained high wind gusts. Wind gusts over 58 mph were reported in Park, Washakie and Johnson Counties, with the maximum gust of 73 mph along Interstate 90 in Johnson County.
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 Aug 6, 2:05 PM MST, 27 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Riverton WY 305 PM MDT Tue Aug 6 2024 .KEY MESSAGES... - Isolated showers and thunderstorms will continue through the evening. Brief outflow wind gusts of 35 to 45 mph are possible with this activity. - Elevated to critical fire weather conditions continue for much of the area today given the gusty outflow winds and lightning threat. - A cold front will approach the Continental Divide on Wednesday, bringing temperatures down east of the Divide Wednesday and Thursday. Rain chances increase for northern Wyoming during this time. - Critical fire weather conditions continue west of the Divide on Wednesday. - A more unsettled pattern is likely to set in by the weekend, keeping temperatures below normal with continued shower chances. && .DISCUSSION... Issued at 300 PM MDT Tue Aug 6 2024 Showers and thunderstorms will be more widespread this afternoon as a stronger shortwave pushes in from the west, flattening the longstanding ridge to our south. Increased moisture (dewpoints generally in the 40s) and ample diurnal heating will allow for MLCAPE values in the 400 to 600 J/kg range by early afternoon. While the strongest cells could be better rain producers today, the primary hazard will again be strong outflow wind gusts. With temperature/dewpoint depressions of 40 to 50 degrees, gusts up to 50 mph are possible with stronger downdrafts. Given the convective outflow potential and still fairly low humidity at the surface, we have issued widespread Red Flag Warnings for much of the area. Storms will wane from west to east around sunset, leaving clearing skies overnight. On Wednesday the ridge will be flattened by a much broader trough dropping south out of Canada. This will usher in cooler temperatures and widespread shower and thunderstorm chances east of the Divide through Wednesday evening. Highs will drop to near seasonal values in central Wyoming and below normal across northern Wyoming. The best chance for appreciable rain will be across the Bighorns and vicinity, though this is not expected to bring widespread heavy rain. The front will struggle to move west of the Divide on Wednesday, and instead locations there will see another warm and dry day. With winds increasing due to a building pressure gradient, this will continue the critical fire weather conditions for most of southern Wyoming through the afternoon. Further ahead, Thursday will be cooler behind the front, especially east of the Divide where highs will likely only reach the 60s and 70s for most locations. Johnson County, in particular, will feel much cooler with highs in the low 60s for most lower elevations (Buffalo's high will be nearly 25 degrees below normal). Precipitation chances will be widespread again along and east of the Divide. Friday will be a little warmer, but still below normal for most locations. Shower and thunderstorm chances will continue, with better chances for a wetting rain east of the Divide given increased moisture advection. Below normal temperatures with additional, widespread rain chances will continue through the weekend as another shortwave moves in. This may be a good time to note for those in the backcountry in the Bighorns, Absarokas, and Winds that a change to notably cooler and wetter conditions will arrive beginning Wednesday. && .AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1127 AM MDT Tue Aug 6 2024 VFR Conditions will prevail through the TAF period. Showers and thunderstorms will become widely scattered across the region this afternoon, mainly between 21Z and 01Z. Have included TEMPO groups at most terminals to highlight most likely timing of any thunderstorm impacts. Gusty outflow winds will be the main concern with any showers and storms today. Showers and storms will end between 02Z and 04Z across the region and winds will be light and mostly variable overnight at all terminals. Winds begin to tick up late in the period ahead of a cold front that will be approaching east of the Divide terminals by the end of the period. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence forecasts. && .FIRE WEATHER... Issued at 300 PM MDT Tue Aug 6 2024 Elevated to critical fire weather conditions will continue through the afternoon owing to convective outflow wind gusts, low humidity, and a lightning threat. Accordingly, the Red Flag Warnings will continue through 7 PM this evening. Convection will wane with sunset with skies clearing overnight. A cold front will move into northern and central Wyoming on Wednesday, bringing cooler temperatures, higher humidity, and rain chances east of the Divide. West of the Divide will not benefit from the front and will instead keep critical fire weather conditions for the afternoon; the Red Flag Warnings will continue there on Wednesday. Thursday and onward will be cooler everywhere, with increased precipitation chances through the weekend. && .RIW WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 7 PM MDT this evening for WYZ275-276- 280>283-285>288. Red Flag Warning until 8 PM MDT Wednesday for WYZ277>279-289. && DISCUSSION...Myers AVIATION...Hensley FIRE WEATHER...Myers
Hazardous Weather Outlook National Weather Service Riverton WY 316 AM MDT Tue Aug 6 2024 WYZ001>020-022>030-071330- Yellowstone National Park-Absaroka Mountains-Cody Foothills- North Bighorn Basin-Southwest Bighorn Basin-Southeast Bighorn 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- 316 AM MDT Tue Aug 6 2024 ...Red Flag Warnings in effect for much of central and southern Wyoming today... This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and tonight. Scattered showers and thunderstorms will occur across much of the forecast area this afternoon and evening. Gusty wind and lightning are the main threats from storms today. .DAYS TWO THROUGH SEVEN...Wednesday through Monday. Critical fire weather conditions continue across southern portions Wednesday as a strong cold front pushes into the area through the morning. Precipitation chances will increase across the north late in the afternoon, continuing east of the Divide through Wednesday night. Scattered rain showers/thunderstorms look likely from Friday through Monday, especially in the afternoon/evening. .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
225 PM MDT Tue Aug 6 2024
WYZ005-007-017-062115-
Owl Creek and Bridger Mountains-Wind River Basin-Southwest Bighorn
Basin-
225 PM MDT Tue Aug 6 2024
...STRONG THUNDERSTORMS WILL IMPACT SOUTH CENTRAL HOT SPRINGS AND
EAST CENTRAL FREMONT COUNTIES THROUGH 315 PM MDT...
At 224 PM MDT, Doppler radar was tracking a cluster of strong
thunderstorms 10 miles southwest of Thermopolis, moving southeast at
20 mph.
HAZARD...Wind gusts up to 50 mph and penny size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
Locations impacted include...
Boysen State Park.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4349 10858 4366 10840 4356 10790 4321 10825
TIME...MOT...LOC 2024Z 302DEG 17KT 4355 10838
MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH
GrossSpecial Weather Statement
National Weather Service Riverton WY
307 PM MDT Tue Aug 6 2024
WYZ012-013-062145-
Jackson Hole-Teton and Gros Ventre Mountains-
307 PM MDT Tue Aug 6 2024
...A STRONG THUNDERSTORM WILL IMPACT SOUTHWESTERN TETON COUNTY
THROUGH 345 PM MDT...
At 307 PM MDT, Doppler radar was tracking a strong thunderstorm near
Jackson, moving east at 25 mph.
HAZARD...Wind gusts up to 40 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor hail damage to vegetation is
possible.
This strong thunderstorm will be near...
Kelly around 320 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4343 11079 4360 11087 4376 11041 4350 11029
TIME...MOT...LOC 2107Z 251DEG 24KT 4354 11074
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH
GrossThe Riverton/Lander radar (KRIW), 137 km away, was scanning. The volume nearest the first event began at 21:32 UTC.
3 thunderstorm wind. Local standard time, as filed.
Wind gusts as high as 59 mph were reported along Highway 120 to the north of Meeteetse.
Wind gusts as high as 62 mph were reported at the Worland airport. The strong wind gusts brought down tree limbs in the city of Worland.
A severe thunderstorm moved eastward across northern Johnson County and brought high wind gusts. Gusts as high as 73 mph occurred along Interstate 90 to the southeast of Buffalo. A 64 mph wind gust was measured at the Johnson County Airport near Buffalo.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2024Every state in 2024This day in weather historyWarnings in Wyoming, August 2024
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: 1204282, 1204283, 1204285.