Moist southwesterly flow aloft moving out ahead of an upper trough over the Pacific Northwest, combined with low level easterly winds, to initiate thunderstorm activity during the late afternoon of June 10 through the early morning hours of June 11. Large hail was reported from several storms.

Thunderstorm Wind in FERGUS, MONTANA
From 10-JUN-16 23:56:00 to 10-JUN-16 23:56:00 (MST-7)
Location: FERGUS
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced a wind gust to 64 mph at Roy 2E. Several large trees were reported down along with several power poles. Sheet metal was also reported to have been blown across the road.

Hail in FERGUS, MONTANA
From 10-JUN-16 18:10:00 to 10-JUN-16 18:10:00 (MST-7)
Location: ROY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1.75 inch hail at Roy 10NE.

Hail in FERGUS, MONTANA
From 10-JUN-16 18:36:00 to 10-JUN-16 18:36:00 (MST-7)
Location: HILGER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1 inch diameter hail at Hilger 5WNW. Additionally, 1 inch diameter tree branches were broken off.

Hail in CASCADE, MONTANA
From 11-JUN-16 03:55:00 to 11-JUN-16 03:55:00 (MST-7)
Location: GREAT FALLS
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1.5 inch diameter hail in Great Falls. The storm produced reports of hail ranging from 1 inch to 1.75 inches in diameter. The hail caused damage to numerous vehicles, especially on the east side of the city. Damage to structures was also reported.

Hail in CHOUTEAU, MONTANA
From 10-JUN-16 15:05:00 to 10-JUN-16 15:05:00 (MST-7)
Location: GERALDINE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1 inch diameter hail at Geraldine.

Hail in CASCADE, MONTANA
From 10-JUN-16 15:40:00 to 10-JUN-16 15:40:00 (MST-7)
Location: MONARCH
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1 inch diameter hail at Monarch.

Thunderstorm Wind in FERGUS, MONTANA
From 10-JUN-16 19:08:00 to 10-JUN-16 19:08:00 (MST-7)
Location: ROY
Magnitude: 101.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

A thunderstorm produced a wind gust to 116 mph at Roy 1E. Wind sensor was rendered inoperative after the gust.

Hail in CHOUTEAU, MONTANA
From 10-JUN-16 14:35:00 to 10-JUN-16 14:35:00 (MST-7)
Location: HIGHWOOD
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A thunderstorm dropped 1.75 inch diameter hail at Highwood 10SE.

Hail in CASCADE, MONTANA
From 10-JUN-16 14:08:00 to 10-JUN-16 14:08:00 (MST-7)
Location: STOCKETT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A thunderstorm dropped 1 inch diameter hail at Stockett. Also, 2 inch diameter hail was reported at Highwood 8S.

Hail in FERGUS, MONTANA
From 10-JUN-16 16:17:00 to 10-JUN-16 16:17:00 (MST-7)
Location: WINIFRED
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1.75 inch diameter hail at Winifred 12W.

Hail in FERGUS, MONTANA
From 10-JUN-16 16:37:00 to 10-JUN-16 16:37:00 (MST-7)
Location: SUFFOLK
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 2 inch diameter hail at Suffolk 2W. Also, 1.25 inch diameter hail fell at Coffee Creek 6N.

Hail in CHOUTEAU, MONTANA
From 10-JUN-16 15:45:00 to 10-JUN-16 15:45:00 (MST-7)
Location: SQUARE BUTTE
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 2 inch diameter hail at Square Butte 1SW.