A couple of rounds of strong to severe thunderstorms developed over portions of northern Wyoming. One thunderstorm caused roof and tree damage in Worland and downed tree limbs near Ten Sleep.
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 couple of rounds of strong to severe thunderstorms developed over portions of northern Wyoming. One thunderstorm caused roof and tree damage in Worland and downed tree limbs near Ten Sleep. This storm then moved northeastward and brought a wind gust of 68 mph to the Greybull airport. Another storm brought half dollar sized hail to northeastern 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 Jul 8, 12:10 PM MST, 3 hours 35 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 110 PM MDT Mon Jul 8 2019 .SHORT TERM...This afternoon through Tuesday The pattern that was in place last week, that helped produce the severe weather, will set back up today. An upper level low will move over the PACNW, with a ridge remaining in place over the region. Contrary to the thinking on Sunday, Gulf moisture has spread back to areas east of the Divide this morning. Dewpoints in the 40s and lower 50s have already been observed over all but southwest portions this morning. CAPE values of 1000-1800 J/kg and LI's of -6 will be in place across western and northern portions this afternoon. A cold front associated with the upper low will enter western portions by early afternoon. Strong thunderstorms will be possible along the front, with small hail and strong winds. As the front progresses eastward this afternoon, there could also be enough shear in the Bighorn Basin for isolated tornadoes. Bulk shear of 40 to 50 kts and lapse rates of 7 to 8C/km add to the likelihood of severe storms over western and northern portions. These conditions will partly be due to the front. Thus, large hail, damaging winds and isolated tornadoes will be possible across the north and the west. Locally heavy rain and flash flooding will also be a threat this afternoon, as PW's remain 100 to 150 percent of normal. Isolated to widely scattered thunderstorms will develop this afternoon from NE Sweetwater/NW Carbon County to Natrona and Johnson counties. Dewpoints in the middle 50s to near 60 degrees will be in place in Johnson County. In addition, CAPE values up to 2500 J/kg and light NE winds will be in place. This will be the most likely location for severe storms this afternoon, with the severe threat continuing into the early evening hours. Isolated to widely scattered thunderstorms will be possible in the remaining areas. The thunderstorm threat will diminish by sunset this evening, with isolated to scattered showers remaining likely over northwest portions. These showers will increase in likelihood by sunrise Tuesday morning. This will be due to the upper low moving over southern MT. These showers will spread across the northern half of the forecast area through the morning and into the afternoon. Isolated thunderstorms will be possible in the afternoon. Strong winds will be the main threat, as the upper level wind flow turns northwest. Storms under this pattern tend to be stronger, despite the lack of instability. .LONG TERM...(Tuesday night through Monday) Issued at 106 PM MDT Mon Jul 8 2019 Shower and thunderstorm activity, mainly across the northern half of the region, will diminish late in the evening Tuesday. Gusty winds and small hail are possible with the storms. Strong upper level ridging will build across Wyoming Wednesday and persist through Thursday with the main storm track north in Montana and Canada. This will bring warmer and drier weather for the CWA. Thursday is still looking to be the hottest day of the period, with highs 5 to 10 degrees above average. Thursday could also see isolated shower activity develop as a weak wave transits the pattern. The heat, low humidity, and breezy winds across the south may be enough for elevated fire weather conditions there. The upper high flattens a bit Friday through early next week with a modest westerly mid-level flow over the region. There will be minor waves transiting through the region during the period with periods of weak ridging between. With these waves enough moisture and instability is indicated for diurnal thunderstorms each day. The best chance for convection is over the north and east, with some strong convection possible at times. With the minor disturbances enhancing the activity, some of the convection could linger into the night. && .AVIATION...For the 18Z TAFS through 18Z Tuesday VFR conditions will occur at the terminal sites through the period. A cold front will move into the west and north and progress through much of the area by 06Z Tuesday. Scattered showers and storms will develop over the west and north in the next hour or two. Some storms in these areas will produce hail and wind gusts over 40 knots. Showers and storms over the central and southern portions will be less numerous this afternoon and evening, but they will be capable of producing outflow wind gusts over 40 knots through 06Z Tuesday. Gusty surface wind speeds will be common the area. Storms will end across the area after sunset this evening, with isolated showers remaining possible over northwest portions tonight. These showers will then spread across the north after 12Z Tuesday. && .FIRE WEATHER... Issued AT 106 PM MDT Mon Jul 8 2019 Isolated to scattered showers and thunderstorms will move across much of the area, with the most numerous storms occurring across the north and west. Some storms could be strong to severe, with strong wind gusts and hail. Gusty winds will continue across southern Wyoming and could bring elevated fire behavior. Relative humidity is in the teens for portions of southern Wyoming. Across northern Wyoming, wind should remain light to moderate outside of any shower or thunderstorm. Mixing and smoke dispersal will range from fair to poor in the north to excellent in central and southern Wyoming. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...LaVoie LONG TERM...Swanson AVIATION...LaVoie FIRE WEATHER...Swanson
Hazardous Weather Outlook National Weather Service Riverton WY 205 PM MDT Mon Jul 8 2019 WYZ001>020-022>030-092015- 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- 205 PM MDT Mon Jul 8 2019 This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...This afternoon and Tonight. Scattered thunderstorms through this evening. Some storms could be severe, especially across the Bighorn Basin to Johnson County and the surrounding mountains. Large hail, damaging winds and locally heavy rain will be the primary hazards, but an isolated tornado could occur. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. Tuesday...Isolated thunderstorms possible in northern Wyoming. Friday through Sunday...Isolated to locally scattered thunderstorms. The best chance will be across the north. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to standard operating procedures. TEAM RIVERTON
Special Weather Statement National Weather Service Riverton WY 358 PM MDT Mon Jul 8 2019 WYZ019-030-082230- East Sweetwater County-Green Mountains and Rattlesnake Range- 358 PM MDT Mon Jul 8 2019 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN FREMONT AND NORTHEASTERN SWEETWATER COUNTIES UNTIL 430 PM MDT... At 357 PM MDT, Doppler radar was tracking a strong thunderstorm near Crooks Gap, which is 11 miles south of Jeffrey City, moving northeast at 20 mph. Penny size hail and wind gusts up to 50 mph will be possible with this storm. This strong thunderstorm will be near... Crooks Gap around 410 PM MDT. Jeffrey City around 430 PM MDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... 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. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. Persons in campgrounds should consider seeking sturdy shelter until this storm passes. && LAT...LON 4206 10823 4262 10788 4247 10748 4197 10798 TIME...MOT...LOC 2157Z 214DEG 19KT 4232 10788 McDonald
Special Weather Statement National Weather Service Riverton WY 358 PM MDT Mon Jul 8 2019 WYZ005-007-017>019-082230- Owl Creek and Bridger Mountains-Wind River Basin-Green Mountains and Rattlesnake Range-Southwest Big Horn Basin-Lander Foothills- 358 PM MDT Mon Jul 8 2019 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HOT SPRINGS AND EAST CENTRAL FREMONT COUNTIES UNTIL 430 PM MDT... At 357 PM MDT, Doppler radar was tracking strong thunderstorms along a line extending from 12 miles west of Boysen State Park to 10 miles southeast of Hudson. Movement was east at 35 mph. Wind gusts up to 50 mph will be possible with these storms. Strong thunderstorms will be near... Sand Draw around 415 PM MDT. Other locations impacted by these storms include Arapahoe Elementary School, Midvale, St Stephens, Bonneville, Riverton Landfill, Fremont County Fairgrounds and Riverton Regional Airport. PRECAUTIONARY/PREPAREDNESS ACTIONS... If on or near Boysen Reservoir, get out of the water and move indoors or inside a vehicle. Remember, lightning can strike out to 10 miles from the parent thunderstorm. If you can hear thunder, you are close enough to be struck by lightning. Move to safe shelter now! Do not be caught on the water in a thunderstorm. && A Severe Thunderstorm Watch remains in effect until 900 PM MDT for central Wyoming. LAT...LON 4362 10783 4276 10781 4272 10861 4347 10863 TIME...MOT...LOC 2157Z 259DEG 29KT 4340 10843 4283 10841 TL
Special Weather Statement
National Weather Service Riverton WY
402 PM MDT Mon Jul 8 2019
WYZ019-020-082230-
Green Mountains and Rattlesnake Range-Natrona County Lower
Elevations-
402 PM MDT Mon Jul 8 2019
...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL NATRONA AND EAST
CENTRAL FREMONT COUNTIES UNTIL 430 PM MDT...
At 402 PM MDT, Doppler radar was tracking a strong thunderstorm 14
miles southwest of Ervay, which is 21 miles northeast of Jeffrey
City, moving northeast at 35 mph.
Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.
This strong thunderstorm will be near...
Ervay around 425 PM MDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Brief rainfall is also occurring with this storm, and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.
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.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.
&&
LAT...LON 4259 10754 4272 10773 4278 10767 4281 10765
4280 10763 4283 10760 4285 10760 4285 10756
4287 10754 4293 10754 4294 10753 4293 10750
4298 10750 4305 10744 4282 10706
TIME...MOT...LOC 2202Z 222DEG 32KT 4271 10756
McDonaldSpecial Weather Statement
National Weather Service Riverton WY
412 PM MDT Mon Jul 8 2019
WYZ005-006-082245-
Southeast Big Horn Basin-Southwest Big Horn Basin-
412 PM MDT Mon Jul 8 2019
...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL HOT SPRINGS AND
NORTHWESTERN WASHAKIE COUNTIES UNTIL 445 PM MDT...
At 412 PM MDT, Doppler radar was tracking a strong thunderstorm 12
miles northwest of Winchester, which is 20 miles west of Worland,
moving northeast at 35 mph.
Nickel size hail and winds in excess of 40 mph will be possible with
this storm.
This strong thunderstorm will be near...
Worland around 445 PM MDT.
Other locations impacted by this storm include Washakie County
Fairgrounds.
A Severe Thunderstorm Watch remains in effect until 900 PM MDT for
central Wyoming.
LAT...LON 4388 10782 4371 10854 4384 10865 4387 10861
4390 10863 4398 10851 4406 10811 4414 10820
4417 10815 4417 10804
TIME...MOT...LOC 2212Z 237DEG 29KT 4396 10837
HulmeSpecial Weather Statement National Weather Service Riverton WY 431 PM MDT Mon Jul 8 2019 WYZ005>007-082300- Owl Creek and Bridger Mountains-Southeast Big Horn Basin-Southwest Big Horn Basin- 431 PM MDT Mon Jul 8 2019 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HOT SPRINGS AND CENTRAL WASHAKIE COUNTIES UNTIL 500 PM MDT... At 430 PM MDT, Doppler radar was tracking a strong thunderstorm over Lucerne, which is near Thermopolis, moving east at 30 mph. Half inch hail and wind gusts up to 50 mph will be possible with this storm. This storm will remain over mainly rural areas of southeastern Hot Springs and central Washakie Counties, including the following locations... Hot Springs County Fairgrounds and Hot Springs County Airport. A Severe Thunderstorm Watch remains in effect until 900 PM MDT for central Wyoming. LAT...LON 4354 10824 4373 10848 4393 10764 4365 10753 TIME...MOT...LOC 2230Z 256DEG 28KT 4371 10820 Hulme
Special Weather Statement National Weather Service Riverton WY 433 PM MDT Mon Jul 8 2019 WYZ019-020-082300- Green Mountains and Rattlesnake Range-Natrona County Lower Elevations- 433 PM MDT Mon Jul 8 2019 ...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL NATRONA COUNTY UNTIL 500 PM MDT... At 432 PM MDT, Doppler radar was tracking a strong thunderstorm near Ervay, which is 39 miles northeast of Jeffrey City, moving northeast at 30 mph. Half inch hail and winds in excess of 40 mph will be possible with this storm. This strong thunderstorm will be near... Waltman and Waltman Rest Area around 455 PM MDT. Powder River around 500 PM MDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... Heavy rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. 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. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 4277 10728 4290 10745 4317 10717 4296 10689 TIME...MOT...LOC 2232Z 223DEG 28KT 4288 10729 McDonald
The Riverton/Lander radar (KRIW), 114 km away, was scanning. The volume nearest the first event began at 22:45 UTC.
2 thunderstorm wind, 1 hail. Local standard time, as filed.
A trained spotter reported tree and roof damage in Worland, Wyoming. Several tree limbs were blown down to the north-northwest of Ten Sleep, Wyoming.
The ASOS at the Greybull airport had multiple wind gusts past 58 mph, including a maximum gust of 68 mph.
A trained spotter reported half dollar sized hail, 21 miles northeast of Buffalo, Wyoming.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wyoming in 2019Every state in 2019This day in weather historyWarnings in Wyoming, July 2019
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: 834091, 834098, 834103.