A shortwave moving along the Canadian border interacted with moisture and instability over North-central MT for strong to severe thunderstorm development. Surface based CAPE was generally less than 500 j/kg, but effective shear above 30 kts and DCAPE as high as 2000 j/kg was enough to produce scattered areas of severe wind gusts.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 11-JUL-21 16:14:00 to 11-JUL-21 16:14:00 (MST-7)
Location: BIG SANDY
Magnitude: 67.00 MG
Reported by: Mesonet

Ambient weather station at 13 W Big Sandy measured a 67 kt (77 mph) thunderstorm wind gust.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 11-JUL-21 16:30:00 to 11-JUL-21 16:30:00 (MST-7)
Location: BIG SANDY
Magnitude: 61.00 EG
Reported by: Law Enforcement

Semi blow off of highway 87 at mile marker 78 and power lines blown down in the same area.

Thunderstorm Wind in HILL, MONTANA
From 11-JUL-21 16:41:00 to 11-JUL-21 16:41:00 (MST-7)
Location: (HVR)HAVRE CITY-CO A
Magnitude: 57.00 MG
Reported by: ASOS

KHVR measured a 57 kt (66 mph) thunderstorm wind gust.

Thunderstorm Wind in HILL, MONTANA
From 11-JUL-21 17:00:00 to 11-JUL-21 17:00:00 (MST-7)
Location: HAVRE
Magnitude: 54.00 MG
Reported by: Mesonet

Station MTM06 (7 WSW Havre) measured a 54 kt (62 mph) thunderstorm wind gust.

Thunderstorm Wind in HILL, MONTANA
From 11-JUL-21 16:05:00 to 11-JUL-21 16:05:00 (MST-7)
Location: INVERNESS
Magnitude: 54.00 MG
Reported by: Department of Highways

MDT Inverness station measured a 54 kt (62 mph) thunderstorm wind gust.

Thunderstorm Wind in TOOLE, MONTANA
From 11-JUL-21 15:59:00 to 11-JUL-21 15:59:00 (MST-7)
Location: GALATA
Magnitude: 56.00 MG
Reported by: Mesonet

Mesonet station at 10 NNE Galata measured a 56 kt (64 mph) thunderstorm wind gust.

Thunderstorm Wind in GLACIER, MONTANA
From 11-JUL-21 14:29:00 to 11-JUL-21 14:29:00 (MST-7)
Location: (CTB)CUTBANK MUNI AR
Magnitude: 55.00 MG
Reported by: ASOS

KCTB measured a 55 kt (63 mph) thunderstorm wind gust.

Thunderstorm Wind in TOOLE, MONTANA
From 11-JUL-21 15:00:00 to 11-JUL-21 15:00:00 (MST-7)
Location: SHELBY ARPT
Magnitude: 52.00 MG
Reported by: Mesonet

Toole County Airport measured a 52 kt (60 mph) thunderstorm wind gust.

Thunderstorm Wind in TOOLE, MONTANA
From 11-JUL-21 21:34:00 to 11-JUL-21 21:34:00 (MST-7)
Location: GALATA
Magnitude: 56.00 MG
Reported by: Mesonet

Measured by ambient weather station.

Thunderstorm Wind in GLACIER, MONTANA
From 11-JUL-21 14:24:00 to 11-JUL-21 14:24:00 (MST-7)
Location: CUTBANK
Magnitude: 55.00 EG
Reported by: Law Enforcement

Power lines down and power outages reported throughout Cut Bank dur to the severe thunderstorm winds.

Hail in GLACIER, MONTANA
From 11-JUL-21 13:35:00 to 11-JUL-21 13:35:00 (MST-7)
Location: SANTA RITA
Magnitude: 1.00 
Reported by: Public

Quarter size (1 inch diameter) hail west of Del Bonita. Hail size was estimated.

High Wind in SOUTHERN LEWIS AND CLARK, MONTANA
From 11-JUL-21 16:31:00 to 11-JUL-21 16:31:00 (MST-7)
Magnitude: 55.00 MG
Reported by: AWOS

K1GM measures 55 kt (63 mph) non-thunderstorm wind gust (distant outflow boundary).

Thunderstorm Wind in CASCADE, MONTANA
From 11-JUL-21 17:23:00 to 11-JUL-21 17:23:00 (MST-7)
Location: GREAT FALLS
Magnitude: 57.00 MG
Reported by: Public

Public measured 57 kt (66 mph) thunderstorm wind gust.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 11-JUL-21 16:20:00 to 11-JUL-21 16:20:00 (MST-7)
Location: LOMA
Magnitude: 53.00 MG
Reported by: Department of Highways

MDT Loma station measured a 53 kt (61 mph) thunderstorm wind gust.

Thunderstorm Wind in HILL, MONTANA
From 11-JUL-21 16:00:00 to 11-JUL-21 16:00:00 (MST-7)
Location: RUDYARD
Magnitude: 56.00 MG
Reported by: Mesonet

Mesonet station at 11 S Rudyard measured a 56 kt (65 mph) thunderstorm wind gust.

Thunderstorm Wind in LIBERTY, MONTANA
From 11-JUL-21 15:30:00 to 11-JUL-21 15:30:00 (MST-7)
Location: LOTHAIR
Magnitude: 50.00 EG
Reported by: Trained Spotter

A trained spotter reported a downed swing set and a significant number of trees limbs blown down due to thunderstorm wind gusts.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 11-JUL-21 16:45:00 to 11-JUL-21 16:45:00 (MST-7)
Location: FT BENTON
Magnitude: 51.00 MG
Reported by: Mesonet

Mesonet station at 18 E Fort Benton measured a 51 kt (59 mph) thunderstorm wind gust.

Thunderstorm Wind in LIBERTY, MONTANA
From 11-JUL-21 15:59:00 to 11-JUL-21 15:59:00 (MST-7)
Location: JOPLIN
Magnitude: 50.00 MG
Reported by: Mesonet

Mesonet station at 10 N Joplin measured a 50 kt (58 mph) thunderstorm wind gust.

Thunderstorm Wind in HILL, MONTANA
From 11-JUL-21 15:58:00 to 11-JUL-21 15:58:00 (MST-7)
Location: INVERNESS
Magnitude: 50.00 MG
Reported by: Mesonet

Mesonet station at 13 S Inverness measured a 50 kt (58 mph) thunderstorm wind gust.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 11-JUL-21 16:24:00 to 11-JUL-21 16:24:00 (MST-7)
Location: VERONA
Magnitude: 61.00 MG
Reported by: Department of Highways

Downed power lines reported along highway 87 near Verona.