Alert archive / Wyoming / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 59, NWS Riverton, WY

August 22, 2026Johnson County, Natrona County, Wyoming

NWS Riverton, WY issued this severe thunderstorm warning at Aug 22, 2026, 7:17 PM MDT for Johnson County, Natrona County, Wyoming. It was in force for 43 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 22, 2026, 7:17 PM MDT (01:17 UTC)
Expired
Aug 22, 2026, 8:00 PM MDT
In force
43 min
Issued by
NWS Riverton, WY
Area
Storm-based polygon
Tornado
Possible
Hail
0.88 in
Wind
60.0 mph

Counties Johnson County, WY, Natrona County, WY

The radar

The Riverton/Lander radar (KRIW), 152 km from the middle of the area, began a volume at 01:18 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

Riverton, WY (KRIW), launched 00:00Z, 1.3 hours before the alert went out and 146 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.

Skew-T log-pSkew-T log-p diagram, Riverton, WY at 00:00Z on 2026-08-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 103 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 00:00Z on 2026-08-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
103 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
2708 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
89 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The office that day

Everything else NWS Riverton, WY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 22, 6:32 PM MDTAreal Flood AdvisoryRIWJohnson3 hr
Aug 22, 6:37 PM MDTSpecial Weather StatementRIWTeton23 min
Aug 22, 6:38 PM MDTSpecial Weather StatementRIW52 min
Aug 22, 7:02 PM MDTSpecial Weather StatementRIW58 min
Aug 22, 7:49 PM MDTSpecial Weather StatementRIWFremont41 min
Aug 22, 7:52 PM MDTSpecial Weather StatementRIWNatrona53 min
Aug 22, 8:23 PM MDTSpecial Weather StatementRIWTeton52 min
Aug 22, 9:46 PM MDTSpecial Weather StatementRIW29 min
Aug 22, 10:10 PM MDTSpecial Weather StatementRIWSublette35 min
Aug 23, 3:06 PM MDTSpecial Weather StatementRIWTeton24 min
Aug 23, 3:11 PM MDTSpecial Weather StatementRIWJohnson34 min
Aug 23, 3:46 PM MDTSpecial Weather StatementRIW29 min
Aug 23, 4:16 PM MDTSpecial Weather StatementRIWSublette29 min
Aug 23, 4:42 PM MDTSpecial Weather StatementRIW48 min
Aug 23, 5:42 PM MDTSpecial Weather StatementRIWFremont33 min
Aug 23, 5:43 PM MDTSpecial Weather StatementRIW32 min

Nearby

Severe Thunderstorm Warnings in Wyoming, 2026Every severe thunderstorm warning in 2026

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.