Alert archive / Wyoming / Severe Thunderstorm Warnings in 2023
Severe Thunderstorm Warning 99, NWS Riverton, WY
NWS Riverton, WY issued this severe thunderstorm warning at Aug 6, 2023, 4:56 PM MDT for Fremont County, Wyoming. It was in force for 34 min. No storm report in the archive falls inside the area while it was in force.
The area
The counties it named.
The facts
- Issued
- Aug 6, 2023, 4:56 PM MDT (22:56 UTC)
- Expired
- Aug 6, 2023, 5:30 PM MDT
- In force
- 34 min
- Issued by
- NWS Riverton, WY
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Hail
- 1.75 in
- Wind
- 50.0 mph
County Fremont County, WY
The radar
The Riverton/Lander radar (KRIW), 13 km from the middle of the area, began a volume at 22:57 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Grand Junction, CO (KGJT), launched 12:00Z, 10.9 hours before the alert went out and 435 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2777 m above ground
- 0-6 km bulk shear
- 52 kt
- 0-1 km storm-relative helicity
- 20 m²/s²
- 0-3 km storm-relative helicity
- 153 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
What forecasters said that day
The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Aug 6, 12:40 PM MDT, 4 hours 16 minutes earlier.
Area forecast discussion, Aug 6, 12:40 PM MDT, 4 hours 16 minutes before
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</html>Hazardous weather outlook, Aug 6, 4:18 AM MDT, 12 hours 38 minutes before
Hazardous Weather Outlook National Weather Service Riverton WY 418 AM MDT Sun Aug 6 2023 WYZ001>020-022>030-071430- 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- 418 AM MDT Sun Aug 6 2023 This Hazardous Weather Outlook is for Western and Central Wyoming. .DAY ONE...Today and tonight. Scattered to numerous showers and thunderstorm over the area, especially for northern Wyoming this afternoon. Locally heavy rain may bring localized flooding. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Monday and Tuesday...Scattered showers and thunderstorms, more numerous over the northern mountains, persist with locally heavy rain the primary hazard. .SPOTTER INFORMATION STATEMENT... Weather spotters are encouraged to report significant weather conditions according to Standard Operating Procedures.
In the hours before
Special weather statement, Aug 6, 2:45 PM MDT, 2 hours 11 minutes before
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</html>Special weather statement, Aug 6, 3:09 PM MDT, 1 hour 47 minutes before
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</html>Special weather statement, Aug 6, 3:13 PM MDT, 1 hour 43 minutes before
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</html>Special weather statement, Aug 6, 4:01 PM MDT, 55 minutes before
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</html>Special weather statement, Aug 6, 4:30 PM MDT, 26 minutes before
Special Weather Statement
National Weather Service Riverton WY
430 PM MDT Sun Aug 6 2023
WYZ015>017-062315-
Wind River Basin-Upper Wind River Basin-Wind River Mountains East-
430 PM MDT Sun Aug 6 2023
...A strong thunderstorm will impact portions of central Fremont
County through 515 PM MDT...
At 430 PM MDT, Doppler radar was tracking a strong thunderstorm over
Crowheart, which is also 25 miles southeast of Dubois, moving
southeast at 20 mph.
HAZARD...Winds in excess of 40 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
This strong thunderstorm will be near...
Crowheart around 435 PM MDT.
Other locations in the path of this storm include Bull Lake and
Diversion Dam Rest Area.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4328 10938 4342 10924 4335 10882 4305 10911
TIME...MOT...LOC 2230Z 305DEG 15KT 4331 10923
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH
VandenBoogartSpecial weather statement, Aug 6, 4:36 PM MDT, 20 minutes before
Special Weather Statement
National Weather Service Riverton WY
436 PM MDT Sun Aug 6 2023
WYZ005-007-062315-
Owl Creek and Bridger Mountains-Southwest Big Horn Basin-
436 PM MDT Sun Aug 6 2023
...A strong thunderstorm will impact portions of southeastern Hot
Springs County through 515 PM MDT...
At 436 PM MDT, Doppler radar was tracking a strong thunderstorm 11
miles southeast of Hamilton Dome, which is also 11 miles west of
Thermopolis, moving east at 30 mph.
HAZARD...Winds in excess of 40 mph and nickel size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Thermopolis and Hot Springs State Park.
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.
&&
LAT...LON 4373 10795 4373 10791 4346 10802 4357 10857
4374 10852 4374 10795
TIME...MOT...LOC 2236Z 282DEG 25KT 4364 10844
MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH
VandenBoogartThe office that day
Everything else NWS Riverton, WY issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 6, 1:44 PM MDT | Special Weather Statement | RIW | Teton | 16 min |
| Aug 6, 2:02 PM MDT | Special Weather Statement | RIW | Hot Springs | 43 min |
| Aug 6, 2:23 PM MDT | Special Weather Statement | RIW | 52 min | |
| Aug 6, 2:45 PM MDT | Special Weather Statement | RIW | 45 min | |
| Aug 6, 3:09 PM MDT | Special Weather Statement | RIW | Hot Springs | 36 min |
| Aug 6, 3:13 PM MDT | Special Weather Statement | RIW | 47 min | |
| Aug 6, 4:01 PM MDT | Special Weather Statement | RIW | Fremont | 29 min |
| Aug 6, 4:09 PM MDT | Areal Flood Advisory | RIW | Park | 3 hr |
| Aug 6, 4:30 PM MDT | Special Weather Statement | RIW | Fremont | 45 min |
| Aug 6, 4:36 PM MDT | Special Weather Statement | RIW | Hot Springs | 39 min |
| Aug 6, 4:52 PM MDT | Areal Flood Advisory | RIW | Park | 2 hr |
| Aug 6, 5:26 PM MDT | Severe Thunderstorm Warning | RIW | Fremont | 49 min |
| Aug 6, 5:46 PM MDT | Areal Flood Advisory | RIW | Fremont | 3 hr |
Nearby
Severe Thunderstorm Warnings in Wyoming, 2023Every severe thunderstorm warning in 2023
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.