Slow moving thunderstorms brought an average of three quarters of an inch of rain in only 20 minutes along with large amounts of small hail on the late afternoon of July 14th. There were many instances of street flooding around Powell, Wyoming with many businesses, houses and the animal shelter flooded.
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.
Slow moving thunderstorms brought an average of three quarters of an inch of rain in only 20 minutes along with large amounts of small hail on the late afternoon of July 14th. There were many instances of street flooding around Powell, Wyoming with many businesses, houses and the animal shelter flooded. Local water cleanup companies reported 50 calls for water cleanup, especially for flooded basements.
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 14, 1:06 PM MST, 2 hours 24 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 206 PM MDT Sun Jul 14 2019 .SHORT TERM...(Sunday afternoon through Monday) Issued AT 206 PM MDT Sun Jul 14 2019 Satellite and radar imagery showing thunderstorms across the Upper Green River Basin and the southern Absaroka Range early Sunday afternoon. Daytime heating, orographics, and some right-entrance region jet dynamics should aid convective development across more areas of the northwest quadrant of the state through early evening. Storms should struggle to gain strength as dynamics are limited and warm mid-level temperatures will further hinder development. The strongest storms are likely to be those forming over the Absarokas and moving east. The primary thunderstorm hazard will be brief heavy rain. The bulk of the convection will be diurnally- driven, thereby diminishing in coverage and intensity between 03Z-06Z/Mon. There will probably be enough lingering moisture to allow for isolated mountain rain showers to continue across the northwest and northern mountains overnight. Like previous days, Monday will begin clear with convection again being driven by solar radiation. A ridge centered over the southern Rockies will expand westward and become elongated across the Desert Southwest. This will largely cut-off the southern moisture stream that has been feeding into the state the past few days. As a result, drier air over the Great Basin will begin to advect into areas west of the Continental Divide. Surface dew points will be less than 40F in this region Monday afternoon with southwest Wyoming seeing readings below 30F. Combined with 700mb temperatures of +16C to +18C to basically cap convection, showers and storms should essentially be non-existent across the southwest. Areas east of the Divide will hold on to higher dew points with 50F+ anticipated in the Bighorn Basin and Johnson County. Several ingredients coming together for stronger afternoon thunderstorms in these areas. An approaching shortwave over southwest Montana by late afternoon along with precipitable water values topping 0.75 inches, bulk shear of 30-40kts, and a slight cooling at 500mb will all aid in convective development and strengthening through the afternoon. Convection will initiate over the Absaroka and Bighorn ranges before moving east into the Bighorn Basin and the plains of Johnson County. Latest SPC Day 2 Outlook keeps this region in a marginal risk for severe thunderstorms with a slight risk near the Montana border. A weak boundary with northerly surface wind will work into the far north during the afternoon. This would create more low-level directional wind shear while possibly advecting in slightly higher dew points. Fremont and Natrona counties should still see isolated, less intense convection. Temperatures will be at or above seasonal normals with the exception of the far north. .LONG TERM...(Monday night through Sunday) Issued AT 206 PM MDT Sun Jul 14 2019 Forecast for the extended period is still on track from previous discussions. A shortwave will move across Montana on Tuesday bringing afternoon showers and thunderstorms to mainly northern Wyoming. Eastern Bighorn Basin and Northern Johnson County will see the greatest threat with CAPEs of 1000 to 1500J/kg. With ample dewpoints of 50 in these locations, expect these to be the areas of strongest convection. A second wave will cross the north on Wednesday for afternoon and evening convective activity, but less coverage than previous days as the flow begins to become zonal aloft. A drier trend will then set in for the rest of the period. Southwest Wyoming will have quite low humidities and gusty afternoon winds starting Tuesday. These conditions will spread to central Wyoming on Wednesday, and into the north on Thursday. Fire weather concerns will have to be closely monitored through Friday. Humidities will still be low Friday and through the weekend. However, a loosening gradient will cause lower winds and decrease the fire weather threat. The northern areas will see a slight rebound in the daytime humidities, so the higher fire weather threat will be in central and southern areas. && .AVIATION...(For the 18Z TAFS through 18Z Monday) Issued at 1130 AM MDT Sun Jul 14 2019 VFR conditions will prevail except for brief MVFR/IFR conditions from thunderstorms. Isolated to scattered thunderstorms will occur this afternoon and evening. The storms should develop a bit later than the last couple of days, and should linger well into the night. The best chances of thunderstorms will be over the north and northwest. && .FIRE WEATHER... Issued AT 206 PM MDT Sun Jul 14 2019 Another in a series of weather disturbances will track from southern Idaho to southern Montana Sunday afternoon and night. This disturbance will help to increase coverage and intensity of showers and storms across northwest and far northern Wyoming. Much of this convection will be diurnally-driven, with the showers and storms diminishing late Sunday evening. The upper-level flow will become more westerly Monday and Tuesday which will continue to favor the far north for showers and storms. The strongest storms are likely to come Monday afternoon across the Bighorn Basin and Johnson County. Wind and moisture fields will favor storms developing over the Absaroka and Bighorn ranges before gaining strength as they move into the lower elevations. Drier conditions are anticipated Wednesday and Thursday. To the south, drier air will advect into areas west of the Continental Divide. This will lead to lowering relative humidity and a slight boost in daytime highs. West to southwest surface wind will increase Monday through Wednesday across southwest and central Wyoming. The combination of slightly above normal temperatures, relative humidity of 10-18 percent, and increasing wind will lead to elevated fire weather conditions in the High Desert District Monday through Thursday, and potentially Natrona and Fremont counties Wednesday and Thursday. Depending upon cloud cover, the temperatures could end up a little warmer and relative humidities a little drier Wednesday and Thursday due to the warming caused by the gusty wind. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...CNJ LONG TERM...Swanson AVIATION...Swanson/CNJ FIRE WEATHER...CNJ
Hazardous Weather Outlook National Weather Service Riverton WY 216 PM MDT Sun Jul 14 2019 WYZ001>020-022>030-151300- 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- 216 PM MDT Sun Jul 14 2019 This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Rest of Today and Tonight Isolated to scattered afternoon and evening thunderstorms with the best chance over the northwest and north. The primary hazards will be heavy rainfall and gusty wind of 35 to 45 mph. .DAYS TWO THROUGH SEVEN...Monday through Saturday Monday...Strong to possibly severe thunderstorms are possible over the Bighorn Basin and Johnson County. The strongest storms are most likely north of a line from Meeteetse to Worland to Kaycee. Elevated fire weather conditions are likely across southwest Wyoming where it will be warm and dry. Tuesday...Isolated to widely scattered thunderstorms mainly over the central and north. Elevated Fire weather conditions in the south. Wednesday and Thursday...Elevated fire weather concerns are possible across mainly southwest and central Wyoming where conditions will be dry and warm with increasing wind. .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
228 PM MDT Sun Jul 14 2019
WYZ005-006-142100-
Southeast Big Horn Basin-Southwest Big Horn Basin-
228 PM MDT Sun Jul 14 2019
...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL HOT SPRINGS AND WEST
CENTRAL WASHAKIE COUNTIES UNTIL 300 PM MDT...
At 228 PM MDT, Doppler radar was tracking a strong thunderstorm 8
miles west of Kirby, which is 10 miles northwest of Thermopolis,
moving east at 30 mph.
Half inch hail and winds in excess of 30 mph will be possible with
this storm.
This strong thunderstorm will be near...
Lucerne and Kirby around 245 PM MDT.
Winchester around 250 PM MDT.
Other locations impacted by this storm include Hot Springs County
Fairgrounds and Hot Springs County Airport.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential 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.
&&
LAT...LON 4396 10809 4366 10797 4366 10801 4364 10835
4365 10835 4364 10837 4364 10842 4381 10849
4386 10845
TIME...MOT...LOC 2028Z 260DEG 27KT 4377 10835
MyersSpecial Weather Statement
National Weather Service Riverton WY
300 PM MDT Sun Jul 14 2019
WYZ005>007-142130-
Owl Creek and Bridger Mountains-Southeast Big Horn Basin-Southwest
Big Horn Basin-
300 PM MDT Sun Jul 14 2019
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HOT SPRINGS COUNTY
UNTIL 330 PM MDT...
At 300 PM MDT, Doppler radar was tracking a strong thunderstorm over
Hot Springs State Park, which is over Thermopolis, moving east at 40
mph.
Pea size hail and winds in excess of 40 mph will be possible with
this storm.
This storm will remain over mainly rural areas of southeastern Hot
Springs County, including the following locations... Hot Springs
County Fairgrounds.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
&&
LAT...LON 4364 10825 4368 10827 4378 10823 4376 10776
4351 10780 4359 10812
TIME...MOT...LOC 2100Z 272DEG 34KT 4365 10817
MyersSpecial Weather Statement National Weather Service Riverton WY 403 PM MDT Sun Jul 14 2019 WYZ017-142230- Wind River Basin- 403 PM MDT Sun Jul 14 2019 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN FREMONT COUNTY UNTIL 430 PM MDT... At 402 PM MDT, Doppler radar was tracking a strong thunderstorm over Pavillion, moving east at 15 mph. Half inch hail and winds in excess of 40 mph will be possible with this storm. This strong thunderstorm will be near... Ocean Lake around 410 PM MDT. Other locations impacted by this storm include Midvale. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential 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. && LAT...LON 4316 10876 4334 10876 4339 10836 4312 10836 TIME...MOT...LOC 2202Z 268DEG 15KT 4325 10867 TL
Special Weather Statement National Weather Service Riverton WY 415 PM MDT Sun Jul 14 2019 WYZ005-007-142245- Owl Creek and Bridger Mountains-Southwest Big Horn Basin- 415 PM MDT Sun Jul 14 2019 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HOT SPRINGS COUNTY UNTIL 445 PM MDT... At 414 PM MDT, Doppler radar was tracking a strong thunderstorm 7 miles south of Thermopolis, moving east at 35 mph. Half inch hail and winds in excess of 40 mph will be possible with this storm. Brief heavy rain is likely with this storm. This storm will remain over mainly rural areas of southeastern Hot Springs County. LAT...LON 4348 10837 4361 10836 4364 10780 4347 10780 TIME...MOT...LOC 2214Z 270DEG 29KT 4355 10827 AR
Special Weather Statement National Weather Service Riverton WY 417 PM MDT Sun Jul 14 2019 WYZ017-018-142245- Wind River Basin-Lander Foothills- 417 PM MDT Sun Jul 14 2019 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL FREMONT COUNTY UNTIL 445 PM MDT... At 416 PM MDT, Doppler radar was tracking a strong thunderstorm near Ethete, which is 11 miles north of Lander, moving northeast at 15 mph. Pea size hail and winds in excess of 40 mph will be possible with this storm. This strong thunderstorm will be near... Arapahoe around 440 PM MDT. Riverton around 445 PM MDT. Other locations impacted by this storm include Arapahoe Elementary School, St Stephens, Fremont County Fairgrounds and Riverton Regional Airport. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential 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. && LAT...LON 4286 10865 4300 10880 4322 10854 4301 10830 TIME...MOT...LOC 2216Z 230DEG 14KT 4298 10865 TL
The Billings radar (KBLX), 123 km away, was scanning. The volume nearest the first event began at 22:29 UTC.
1 flash flood. Local standard time, as filed.
Nearly an inch of rain and a large amount of large hail fell in only 20 minutes around Powell, Wyoming. The result were numerous areas that were flooded, including streets, businesses and homes. The main damage was from water in basements and flooded roads.
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: 835084.