A thunderstorm become severe in eastern Sweetwater County and brought high winds. At Bitter Creek, a maximum wind gust of 76 mph was recorded.
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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 thunderstorm become severe in eastern Sweetwater County and brought high winds. At Bitter Creek, a maximum wind gust of 76 mph was recorded.
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 Jun 18, 1:16 PM MST, 29 minutes earlier.
Area Forecast Discussion National Weather Service Riverton WY 216 PM MDT Tue Jun 18 2019 .SHORT TERM...(This evening through Wednesday) Issued at 210 PM MDT Tue Jun 18 2019 Unstable northwest mid-level flow with ample surface moisture continues again today to produce scattered showers and thunderstorms. Thus far the storms have remained non-severe with possible gusts around 30 mph and brief heavy rain with some small hail. Later this afternoon and into the evening, some storms may become stronger, especially over Johnson and eastern Natrona Counties. SPC has a marginal risk of severe storms for this area. All high resolutions models are indicating that the showers and thunderstorms are likely to continue through the late evening hours as has been occurring the past few days. Skies should remain partly cloudy overnight with temperatures similar to this morning. The pattern looks to shift on Wednesday to more westerly and an upper-level just moves into Washington and Oregon. Surface winds across southern and central WY as well as the higher terrain should increase out of the west. Areas will see 20-30 mph sustained wind with gusts of 40 mph. This flow will also bring drier air to much of southwest WY as temperatures climb a few degrees to the mid 70s to low 80s. A weak boundary is expected to remain along the MT/WY border wednesday. As the left front quad of the jet moves over that area Wednesday afternoon, scattered showers and thunderstorms are expected from YNP eastward to the Bighorns and into Johnson County. SPC already has that area in a marginal risk for severe storms. As the area of convective activity organizes and moves eastward during the late afternoon, expecting the wind across the Bighorn Basin and Johnson County to shift to the north. .LONG TERM...(Wednesday night through Tuesday) Issued at 158 PM MDT Tue Jun 18 2019 Showers and thunderstorms from the weak boundary over Montana will linger in the north Wednesday night through about midnight. Winds in the south will continue to gust through midnight as well, decreasing from west to east shortly afterwards. Clearer skies overnight and Thursday morning followed by increased cloudiness in the afternoon will lead to slightly cooler conditions over most of the area Thursday. Westerly winds will become strong again Thursday afternoon as our next weather system draws nearer. Another round of showers and thunderstorms is in store for the north but southern Wyoming will see dry conditions with humidities in the low 20s. This area will be worth watching as it is approaching near critical fire weather. Friday will see a chance of showers and storms over the north again with isolated activity in the central and south. A cool day with highs mainly in the 60s with some places only reaching the upper 50s. Some snow in the higher mountain elevations of NW WY is possible Friday into Fri night. Saturday will remain on the cool side with 60s for highs. Some afternoon and evening showers and storms will occur due to a weather disturbance in the flow. Sunday will start out dry in the morning, then showers and storms will develop in the afternoon through the evening hours. High temps a little warmer on Sunday. Next Monday and Tuesday may remain unsettled with the chance of showers and storms over the region. High temps will be warmer next Monday and Tuesday with mainly 70s with some lower 80s in places. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 158 PM MDT Tue Jun 18 2019 Afternoon development of showers and thunderstorms has begun, starting in the higher elevations, then spreading east southeast during the mid afternoon and evening. All terminal sites east of the Divide are expected to see VCTS sometime during the day. West of the divide will have less chance for lightning so will be capped at VCSH. Winds will remain fairly light for most areas, except for locally gusty winds near thunderstorms. Some showers may linger over the region through 09Z Wednesday. VFR conditions will prevail at the terminal sites, but a period of MVFR/IFR conditions may occur if a storm directly impacts an airport. Expect moderate to strong westerly winds at most locations Wednesday afternoon. && .FIRE WEATHER... Issued AT 200 PM MDT Tue Jun 18 2019 Scattered showers and thunderstorms in northwest flow will continue late this afternoon into the evening hours, with the stormy activity expected to continue through midnight. Some of the storms may produce gusty outflow over 30 mph along with brief heavy rain and some small hail, and some stronger storms are possible over Johnson and eastern Natrona counties too. More westerly flow will push into WY on Wednesday, bringing slightly drier and warmer air to the southern two-thirds of the state. Sustained winds over the higher terrain and from southern into central WY are expected in the 20-30 mph range. Afternoon humidities are likely in the low 20s in the lower elevations of southern and central WY. A weak boundary along the WY/MT border along with upper level strong winds will cause scattered showers and thunderstorms from YNP eastward to the Bighorns and into Johnson County. These storms should create a north wind push into the Bighorn Basin and Johnson County after 6pm Wed. A larger low pressure system is expected over the northern Rockies Thursday into Friday to bring more wind and precipitation. && .RIW WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...McDonald LONG TERM...Hulme AVIATION...Hulme FIRE WEATHER...McDonald
Hazardous Weather Outlook National Weather Service Riverton WY 245 AM MDT Tue Jun 18 2019 WYZ001>020-022>030-191200- 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- 245 AM MDT Tue Jun 18 2019 This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and Tonight Another day of isolated to scattered thunderstorms, mainly in the afternoon and evening. .DAYS TWO THROUGH SEVEN...Wednesday through Monday Wednesday and Thursday...Isolated thunderstorms over the north. Elevated fire conditions possible in central and southern Wyoming. Friday and Saturday...A chance of thunderstorms over most of the area. Sunday and Monday...A chance of thunderstorms in the west and north. Isolated storms elsewhere. .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
1134 AM MDT Tue Jun 18 2019
WYZ014-015-181800-
Wind River Mountains West-Wind River Mountains East-
1134 AM MDT Tue Jun 18 2019
...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL FREMONT COUNTY
UNTIL NOON MDT...
At 1132 AM MDT, Doppler radar was tracking a strong thunderstorm near
South Pass City, which is 19 miles south of Lander, moving southeast
at 10 mph.
Half inch hail will be possible with this storm.
This strong thunderstorm will be near...
Atlantic City around 1138 AM MDT.
South Pass City around 1145 AM MDT.
Other locations impacted by this storm include Atlantic City.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Brief 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.
Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.
&&
LAT...LON 4250 10892 4264 10871 4259 10859 4257 10857
4255 10852 4254 10852 4253 10855 4253 10857
4251 10862 4244 10868 4243 10873 4241 10879
TIME...MOT...LOC 1732Z 314DEG 7KT 4255 10874
McDonaldSpecial Weather Statement National Weather Service Riverton WY 102 PM MDT Tue Jun 18 2019 WYZ026-027-181930- Upper Green River Basin-South Lincoln County- 102 PM MDT Tue Jun 18 2019 ...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL LINCOLN AND WESTERN SWEETWATER COUNTIES UNTIL 130 PM MDT... At 100 PM MDT, Doppler radar was tracking a strong thunderstorm near Fontenelle Reservoir, which is 28 miles south of Big Piney, moving southeast at 20 mph. Penny size hail and winds in excess of 30 mph will be possible with this storm. Hail could also pile up on the roadways causing difficult travel. This strong thunderstorm will be near... Fontenelle Reservoir around 110 PM MDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... Brief 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. If on or near Fontenelle 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. && LAT...LON 4215 11033 4225 11010 4201 10982 4185 11015 TIME...MOT...LOC 1900Z 327DEG 16KT 4212 11016 McDonald
The Riverton/Lander radar (KRIW), 159 km away, was scanning. The volume nearest the first event began at 20:45 UTC.
1 thunderstorm wind. Local standard time, as filed.
The weather sensor at Bitter Creek along Interstate 80 had a wind gust to 76 mph.
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, June 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: 823989.