A strong area of high pressure over the Great Basin/Rocky Mountain region and a low pressure system dropping south and east into Saskatchewan brought a strong cold front across central and eastern Montana. Very hot temperatures were in place ahead of the front - reaching the upper 90s and low 100s. Dewpoints were in the 60s and 70s ahead of the front. All of this, combined with strong upper-level winds, provided plenty of instability for severe thunderstorms. By late afternoon, storms began to form and move across northeast Montana with 60 to 75 mph wind gusts. This system moved into North Dakota by approximately 10 PM MDT.

Thunderstorm Wind in VALLEY, MONTANA
From 10-JUL-18 16:30:00 to 10-JUL-18 16:30:00 (MST-7)
Location: HINSDALE
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported damage to a large rodeo arena and some outbuildings blown down.

Thunderstorm Wind in VALLEY, MONTANA
From 10-JUL-18 16:30:00 to 10-JUL-18 16:30:00 (MST-7)
Location: HINSDALE
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter estimated wind gusts up to 70 mph.

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

Trained spotter estimated hail up to the size of quarters.

Thunderstorm Wind in VALLEY, MONTANA
From 10-JUL-18 16:32:00 to 10-JUL-18 16:37:00 (MST-7)
Location: HINSDALE
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Saco US-2 DOT site measured wind gusts of 60 mph from 4:32 PM MST to 4:37 PM MST.

Thunderstorm Wind in VALLEY, MONTANA
From 10-JUL-18 17:05:00 to 10-JUL-18 17:05:00 (MST-7)
Location: GLASGOW INTL AIRPORT (KGGW)
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Off duty NWS Employee reported large tree branches broken off and estimated 60 mph wind gusts.

Thunderstorm Wind in ROOSEVELT, MONTANA
From 10-JUL-18 19:00:00 to 10-JUL-18 19:00:00 (MST-7)
Location: POPLAR ARPT
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported a tree two feet in diameter twisted, with a few six to eight inch diameter branches broken off.

Thunderstorm Wind in SHERIDAN, MONTANA
From 10-JUL-18 18:54:00 to 10-JUL-18 18:54:00 (MST-7)
Location: PLENTYWOOD
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Mesonet site on the northwest side of Plentywood measured a 65 mph wind gust.

Thunderstorm Wind in SHERIDAN, MONTANA
From 10-JUL-18 19:17:00 to 10-JUL-18 19:17:00 (MST-7)
Location: COMERTOWN DOT
Magnitude: 65.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Comertown Turn-Off MT-5 DOT site measured a 75 mph wind gust.

Hail in ROOSEVELT, MONTANA
From 10-JUL-18 19:32:00 to 10-JUL-18 19:32:00 (MST-7)
Location: FT KIPP
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported mostly nickel and dime size hail along with a few quarter size hail stones. Time estimated by radar.

Thunderstorm Wind in VALLEY, MONTANA
From 10-JUL-18 17:25:00 to 10-JUL-18 17:25:00 (MST-7)
Location: BAYLOR
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter estimated 60 mph wind gusts.

Thunderstorm Wind in PHILLIPS, MONTANA
From 10-JUL-18 15:45:00 to 10-JUL-18 15:45:00 (MST-7)
Location: MALTA SOUTH DOT
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Malta South US-191 DOT site recorded a 58 mph wind gust.

Thunderstorm Wind in VALLEY, MONTANA
From 10-JUL-18 17:25:00 to 10-JUL-18 17:25:00 (MST-7)
Location: GLASGOW
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Agrimet mesonet site Glasgow 3W recorded a 70 mph wind gust.

Thunderstorm Wind in VALLEY, MONTANA
From 10-JUL-18 17:38:00 to 10-JUL-18 17:38:00 (MST-7)
Location: FT PECK
Magnitude: 59.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter measured a 68 mph wind gust.

Thunderstorm Wind in VALLEY, MONTANA
From 10-JUL-18 17:55:00 to 10-JUL-18 17:55:00 (MST-7)
Location: LUSTRE
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Mesonet site Lustre 8SSW measured a 60 mph wind gust.

Thunderstorm Wind in ROOSEVELT, MONTANA
From 10-JUL-18 18:19:00 to 10-JUL-18 18:19:00 (MST-7)
Location: WOLF PT INTL AIRPORT(KOLF)
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Wolf Point airport ASOS site measured a 58 mph wind gust.

Thunderstorm Wind in DANIELS, MONTANA
From 10-JUL-18 18:30:00 to 10-JUL-18 18:30:00 (MST-7)
Location: FLAXVILLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter on the east side of Flaxville estimated a 60 mph wind gust.