A large area of low pressure at the surface combined with a very unstable atmosphere and a hot moist air from the south to quickly form strong and severe thunderstorms during the afternoon and evening hours, which moved northward through the eastern edge of Montana.

Funnel Cloud in SHERIDAN, MONTANA
From 23-JUL-20 18:09:00 to 23-JUL-20 18:09:00 (MST-7)
Location: PLENTYWOOD
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported a funnel cloud near Plentywood, which was coincident with rotation seen on radar.

Hail in WIBAUX, MONTANA
From 23-JUL-20 15:30:00 to 23-JUL-20 15:30:00 (MST-7)
Location: CARLYLE
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported hail up to the size of ping pong balls, as well as wind gusts estimated at 50 mph.

Hail in WIBAUX, MONTANA
From 23-JUL-20 16:20:00 to 23-JUL-20 16:20:00 (MST-7)
Location: WIBAUX
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported half dollar size hail.  Time estimated from radar.

Thunderstorm Wind in SHERIDAN, MONTANA
From 23-JUL-20 18:15:00 to 23-JUL-20 18:15:00 (MST-7)
Location: PLENTYWOOD
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported singles torn off a roof.  Wind speed is estimated.

Thunderstorm Wind in SHERIDAN, MONTANA
From 23-JUL-20 18:20:00 to 23-JUL-20 18:20:00 (MST-7)
Location: PLENTYWOOD
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter and Emergency Preparation Coordinator at the local hospital reported small outbuildings, small trees, and some power lines blown down.  Wind speed is estimated.

Thunderstorm Wind in SHERIDAN, MONTANA
From 23-JUL-20 18:30:00 to 23-JUL-20 18:30:00 (MST-7)
Location: PLENTYWOOD
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported three large spruce trees up to 70 feet tall and one cottonwood tree blown down.  Wind speed is estimated.

Thunderstorm Wind in RICHLAND, MONTANA
From 23-JUL-20 17:38:00 to 23-JUL-20 17:38:00 (MST-7)
Location: SIOUX PASS DOT
Magnitude: 57.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

At the Sioux Pass MT-16 DOT site (MTSOO), a 66 mph wind gust was recorded.  Winds at this site were also witnessed by an off-duty NWS employee.

Thunderstorm Wind in SHERIDAN, MONTANA
From 23-JUL-20 18:10:00 to 23-JUL-20 18:10:00 (MST-7)
Location: PLENTYWOOD
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Cooperative observer reported several trees blown over, as well as many tree limbs broken off or stripped of leaves.  Time is estimated from radar.

Thunderstorm Wind in SHERIDAN, MONTANA
From 23-JUL-20 18:15:00 to 23-JUL-20 18:15:00 (MST-7)
Location: PLENTYWOOD
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Assistant DES Coordinator for Sheridan County reported wind gusts up to 70 mph.

Thunderstorm Wind in DAWSON, MONTANA
From 23-JUL-20 16:40:00 to 23-JUL-20 16:40:00 (MST-7)
Location: INTAKE
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported many shingles torn off a roof and debris flying around.  Wind speed is estimated.

Thunderstorm Wind in SHERIDAN, MONTANA
From 23-JUL-20 18:20:00 to 23-JUL-20 18:20:00 (MST-7)
Location: PLENTYWOOD SHRWD ARP
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The mesonet site at the Plentywood airport (GGWPW), recorded at 67 mph wind gust.  Time estimated from radar.