Showers and thunderstorms initially developed over the higher terrain of the Laramie Range late in the afternoon on 6/21, rapidly increasing in both coverage and intensity as they tracked slowly eastward through the evening. This activity evolved into a large, slow moving cluster of moderate to heavy rain and embedded thunderstorms, with pockets of small to marginally severe (quarter to half dollar sized) hail associated with the strongest precipitation cores. Flash flooding was also observed in multiple locations due to the extended residence time of the higher rainfall rates.

Hail in PLATTE, WYOMING
From 21-JUN-23 16:20:00 to 21-JUN-23 16:20:00 (MST-7)
Location: NATWICK
Magnitude: 1.00 
Reported by: Trained Spotter

A trained spotter located 7 miles SW of Wheatland reported quarter sized hail.

Hail in PLATTE, WYOMING
From 21-JUN-23 16:44:00 to 21-JUN-23 16:44:00 (MST-7)
Location: NATWICK
Magnitude: 1.00 
Reported by: Public

The public reported quarter sized hail near Wheatland Reservoir Number 1.

Hail in NIOBRARA, WYOMING
From 21-JUN-23 16:30:00 to 21-JUN-23 16:30:00 (MST-7)
Location: VAN TASSELL
Magnitude: 1.00 
Reported by: Trained Spotter

Trained weather spotters observed quarter sized hail 3 miles NNE of Van Tassel.

Hail in PLATTE, WYOMING
From 21-JUN-23 16:32:00 to 21-JUN-23 16:32:00 (MST-7)
Location: NATWICK
Magnitude: 1.50 
Reported by: Storm Chaser

Ping-pong ball sized hail was reported by a storm chaser approximately 21 miles SW of Wheatland.

Tornado in GOSHEN, WYOMING
From 21-JUN-23 18:44:00 to 21-JUN-23 18:46:00 (MST-7)
Location: YODER
Tornado F-scale: EFU
Reported by: Trained Spotter

A trained spotter reported a stovepipe tornado touchdown 3 miles SW of Yoder. Tornado quickly become rain-wrapped and drifted to the northwest.

Hail in LARAMIE, WYOMING
From 21-JUN-23 16:40:00 to 21-JUN-23 16:40:00 (MST-7)
Location: IRON MOUNTAIN
Magnitude: 1.50 
Reported by: Public

The public reported I-25 covered in small hail with the largest stones up to 1.5 inches in diameter. Location was approximately 12 miles north of Whitaker, or 11 miles south of Chugwater.

Hail in PLATTE, WYOMING
From 21-JUN-23 16:32:00 to 21-JUN-23 16:32:00 (MST-7)
Location: NATWICK
Magnitude: 1.50 
Reported by: Storm Chaser

Ping-pong ball sized hail was reported by a storm chaser approximately 21 miles SW of Wheatland.

Hail in NIOBRARA, WYOMING
From 21-JUN-23 17:10:00 to 21-JUN-23 17:10:00 (MST-7)
Location: (LSK)LUSK AIRPORT
Magnitude: 1.00 
Reported by: Trained Spotter

A trained spotter reported drifts of penny to quarter sized hail approximately 9 miles south of Lusk.

Flash Flood in LARAMIE, WYOMING
From 21-JUN-23 17:30:00 to 21-JUN-23 17:30:00 (MST-7)
Location: (82V)PINE BLUFFS AIRPORT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency Management officials reported water flowing over roads and pooling in fields in extreme southeastern Laramie County approximately 8 miles south of Pine Bluffs.

Flash Flood in PLATTE, WYOMING
From 21-JUN-23 19:56:00 to 21-JUN-23 19:56:00 (MST-7)
Location: CHUGWATER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Fire Chief reported localized flash flooding in and near Chugwater.