An unstable southwesterly flow aloft developed over the region on Friday July 3rd and continued through Wednesday July 8th when a Pacific trough displaced moisture and instability to the east. There were mostly sub-severe hail and winds gusts reported for a majority of days during this evening but the aforementioned trough provided adequate wind shear (30 to 55 kts), CAPE (1500 to 3500 j/kg), and moisture (td 50s and 60s) for more widespread severe weather on Tuesday July 7th. Over two dozen reports of severe hail and wind gusts were reported as storms developed over the southwest and moved northeastward into Central and North-central Montana.

Thunderstorm Wind in MEAGHER, MONTANA
From 03-JUL-20 15:40:00 to 03-JUL-20 15:40:00 (MST-7)
Location: WHITE SULPHUR SPGS
Magnitude: 53.00 MG
Reported by: Mesonet

Mesonet station K7S6 3.6 S White Sulphur Springs reported a thunderstorm wind gust of 53 kts (61 mph).

Thunderstorm Wind in LEWIS AND CLARK, MONTANA
From 03-JUL-20 16:56:00 to 03-JUL-20 16:56:00 (MST-7)
Location: MARYSVILLE
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

MDOT station at MacDonald Pass reported a 56 kt (64 mph) thunderstorm wind gust.

Hail in JUDITH BASIN, MONTANA
From 04-JUL-20 16:58:00 to 04-JUL-20 16:58:00 (MST-7)
Location: STANFORD
Magnitude: 1.00 
Reported by: Public

Photo of quarter size hail was sent via twitter.

Hail in GALLATIN, MONTANA
From 07-JUL-20 13:30:00 to 07-JUL-20 13:30:00 (MST-7)
Location: GALLATIN GATEWAY
Magnitude: 1.00 
Reported by: Public

Quarter size hail reported via twitter.

Hail in GALLATIN, MONTANA
From 07-JUL-20 12:18:00 to 07-JUL-20 12:18:00 (MST-7)
Location: BOZEMAN HOT SPGS
Magnitude: 1.00 
Reported by: Trained Spotter

Trained spotter called in and tweeted image of quarter size hail.

Hail in GALLATIN, MONTANA
From 07-JUL-20 12:20:00 to 07-JUL-20 12:20:00 (MST-7)
Location: GALLATIN GATEWAY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Member of public relayed report of quarter size hail via mPing.

Hail in GALLATIN, MONTANA
From 07-JUL-20 12:25:00 to 07-JUL-20 12:25:00 (MST-7)
Location: BOZEMAN
Magnitude: 1.00 
Reported by: Public

Member of public reported quarter size hail.

Hail in MEAGHER, MONTANA
From 07-JUL-20 12:30:00 to 07-JUL-20 12:30:00 (MST-7)
Location: RINGLING
Magnitude: 1.50 
Reported by: Post Office

Post Office reported ping pong ball size (1.5 inch diameter) hail.

Hail in GALLATIN, MONTANA
From 07-JUL-20 12:30:00 to 07-JUL-20 12:30:00 (MST-7)
Location: BOZEMAN
Magnitude: 1.75 
Reported by: Trained Spotter

Trained spotter reported golf ball size (1.75 inch diameter) hail.

Hail in GALLATIN, MONTANA
From 07-JUL-20 12:30:00 to 07-JUL-20 12:30:00 (MST-7)
Location: BOZEMAN
Magnitude: 1.00 
Reported by: Public

Member of public reports quarter size hail.

Hail in CHOUTEAU, MONTANA
From 07-JUL-20 12:45:00 to 07-JUL-20 12:45:00 (MST-7)
Location: LOMA
Magnitude: 1.00 
Reported by: Trained Spotter

Trained spotter reported penny size (.75 inch diameter) and some quarter size hail (1 inch diameter) covering the ground. Some crop damage observed.

Hail in GALLATIN, MONTANA
From 07-JUL-20 12:50:00 to 07-JUL-20 12:50:00 (MST-7)
Location: BOZEMAN
Magnitude: 1.00 
Reported by: CoCoRaHS

COCRAHS reported quarter size hail.

Hail in GALLATIN, MONTANA
From 07-JUL-20 12:57:00 to 07-JUL-20 12:57:00 (MST-7)
Location: BOZEMAN
Magnitude: 1.25 
Reported by: Public

Member of public reported half dollar size (1.25 inch diameter) hail via mPing.

Hail in CHOUTEAU, MONTANA
From 07-JUL-20 12:59:00 to 07-JUL-20 12:59:00 (MST-7)
Location: LOMA
Magnitude: 1.00 
Reported by: Trained Spotter

Trained spotter reported quarter size hail.

Hail in MEAGHER, MONTANA
From 07-JUL-20 13:05:00 to 07-JUL-20 13:05:00 (MST-7)
Location: MARTINSDALE
Magnitude: 1.50 
Reported by: Public

Member of public reported ping pong ball size (1.5 inch diameter) via Facebook.

Hail in HILL, MONTANA
From 07-JUL-20 13:25:00 to 07-JUL-20 13:25:00 (MST-7)
Location: HINGHAM
Magnitude: 1.75 
Reported by: Public

Member of public reported golf ball size (1.75 inch diameter) hail.

Hail in GALLATIN, MONTANA
From 07-JUL-20 13:30:00 to 07-JUL-20 13:30:00 (MST-7)
Location: GALLATIN GATEWAY
Magnitude: 1.00 
Reported by: Public

Member of public reported quarter size hail via twitter.

Hail in HILL, MONTANA
From 07-JUL-20 13:45:00 to 07-JUL-20 13:45:00 (MST-7)
Location: ROCKY BOY
Magnitude: 1.00 
Reported by: Law Enforcement

Dime (.75 inch diameter) and quarter (1 inch diameter) hail reported.

Hail in FERGUS, MONTANA
From 07-JUL-20 13:55:00 to 07-JUL-20 13:55:00 (MST-7)
Location: DENTON
Magnitude: 1.50 
Reported by: Trained Spotter

Trained spotter reported seeing a few ping pong ball size (1.5 inch diameter) hail stones.

Hail in FERGUS, MONTANA
From 07-JUL-20 14:10:00 to 07-JUL-20 14:10:00 (MST-7)
Location: HILGER
Magnitude: 1.50 
Reported by: Trained Spotter

Trained spotter reported ping pong ball (1.50 inch diameter) hail, 45 mph thunderstorm wind gusts, and just over .75 inches of rain.

Thunderstorm Wind in FERGUS, MONTANA
From 07-JUL-20 14:34:00 to 07-JUL-20 14:34:00 (MST-7)
Location: ROY
Magnitude: 75.00 MG
Reported by: AWOS

AWOS station K1OM Oscar measured a 65 kt (75 mph) thunderstorm wind gust.

Hail in GALLATIN, MONTANA
From 07-JUL-20 14:40:00 to 07-JUL-20 14:40:00 (MST-7)
Location: BOZEMAN
Magnitude: 1.00 
Reported by: Public

Member of public reported quarter size hail.

Thunderstorm Wind in FERGUS, MONTANA
From 07-JUL-20 14:41:00 to 07-JUL-20 14:41:00 (MST-7)
Location: FORESTGROVE
Magnitude: 55.00 MG
Reported by: AWOS

AWOS station K1NM November measured a 55 kt (63 mph) thunderstorm wind gust.

Hail in FERGUS, MONTANA
From 07-JUL-20 15:00:00 to 07-JUL-20 15:00:00 (MST-7)
Location: GRASSRANGE
Magnitude: 1.25 
Reported by: Trained Spotter

Trained spotter reported four minutes of hail ranging from pea size (.25 inch diameter) to half dollar size (1.25 inch diameter).

Hail in FERGUS, MONTANA
From 07-JUL-20 15:00:00 to 07-JUL-20 15:00:00 (MST-7)
Location: GRASSRANGE
Magnitude: 1.25 
Reported by: Public

Member of public relayed image of half dollar size (1.25 inch diameter) hail via twitter.

Thunderstorm Wind in BLAINE, MONTANA
From 07-JUL-20 15:30:00 to 07-JUL-20 15:30:00 (MST-7)
Location: HOGELAND
Magnitude: 50.00 EG
Reported by: Trained Spotter

Trained spotter reported downed 15 to 20 foot crab apple tree and flag pole due to thunderstorm wind gusts. Nearly an inch of rain fell.

Thunderstorm Wind in BLAINE, MONTANA
From 07-JUL-20 15:54:00 to 07-JUL-20 15:54:00 (MST-7)
Location: TURNER
Magnitude: 50.00 EG
Reported by: Trained Spotter

Trained spotter reported 3 to 4 foot chunks and larger tree branches were blown down due to thunderstorm wind gusts.

Hail in BLAINE, MONTANA
From 07-JUL-20 16:00:00 to 07-JUL-20 16:00:00 (MST-7)
Location: TURNER
Magnitude: 1.00 
Reported by: Public

Member of public reported quarter size hail and gusty winds.

Thunderstorm Wind in BLAINE, MONTANA
From 07-JUL-20 16:18:00 to 07-JUL-20 16:18:00 (MST-7)
Location: FT BELKNAP
Magnitude: 57.00 MG
Reported by: RAWS

RAWS station FBLM8 Fort Belknap measured a 57 kt (66 mph) thunderstorm wind gust.