Warm temperatures, combined with steep lapse rates and favorable wind shear, resulted in several long-lasting severe thunderstorms. Several locations reported golf ball size hail.

Hail in YELLOWSTONE, MONTANA
From 23-MAY-18 14:20:00 to 23-MAY-18 14:20:00 (MST-7)
Location: WORDEN
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in YELLOWSTONE, MONTANA
From 23-MAY-18 14:30:00 to 23-MAY-18 14:30:00 (MST-7)
Location: WORDEN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in YELLOWSTONE, MONTANA
From 23-MAY-18 15:12:00 to 23-MAY-18 15:12:00 (MST-7)
Location: BILLINGS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in YELLOWSTONE, MONTANA
From 23-MAY-18 15:12:00 to 23-MAY-18 15:12:00 (MST-7)
Location: POMPEYS PILLAR
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ROSEBUD, MONTANA
From 23-MAY-18 15:12:00 to 23-MAY-18 15:12:00 (MST-7)
Location: COLSTRIP
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in YELLOWSTONE, MONTANA
From 23-MAY-18 15:15:00 to 23-MAY-18 15:15:00 (MST-7)
Location: BILLINGS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ROSEBUD, MONTANA
From 23-MAY-18 16:07:00 to 23-MAY-18 16:07:00 (MST-7)
Location: ANGELA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CUSTER, MONTANA
From 23-MAY-18 17:00:00 to 23-MAY-18 17:00:00 (MST-7)
Location: FT KEOGH
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CUSTER, MONTANA
From 23-MAY-18 17:05:00 to 23-MAY-18 17:05:00 (MST-7)
Location: FT KEOGH
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CUSTER, MONTANA
From 23-MAY-18 17:00:00 to 23-MAY-18 17:00:00 (MST-7)
Location: MOON CREEK
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail broke a window in a home.

Hail in CUSTER, MONTANA
From 23-MAY-18 17:10:00 to 23-MAY-18 17:10:00 (MST-7)
Location: FT KEOGH
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in CARTER, MONTANA
From 23-MAY-18 17:30:00 to 23-MAY-18 17:30:00 (MST-7)
Location: RIDGEWAY
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Hail in CARTER, MONTANA
From 23-MAY-18 17:44:00 to 23-MAY-18 17:44:00 (MST-7)
Location: BOYES
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in TREASURE, MONTANA
From 23-MAY-18 17:45:00 to 23-MAY-18 17:45:00 (MST-7)
Location: SARPY JCT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in ROSEBUD, MONTANA
From 23-MAY-18 18:00:00 to 23-MAY-18 18:00:00 (MST-7)
Location: ASHLAND
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CARTER, MONTANA
From 23-MAY-18 17:30:00 to 23-MAY-18 17:30:00 (MST-7)
Location: RIDGEWAY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter