A very similar set-up was in place on the 7th as was the case on the 6th.
An upper low was situated over the Pacific Northwest. This resulted in a southwest flow aloft across the Billings Forecast Area. This pattern was quite favorable for the development of severe thunderstorms. A strong southeast, surface flow advected 50+ degree dewpoints from the central Plains northwestward across the entire Billings Forecast Area. In addition, a strong jet stream overhead provided plenty of speed shear over the area. This all resulted in a few supercell thunderstorms which then evolved into a squall line.

Thunderstorm Wind in GOLDEN VALLEY, MONTANA
From 07-JUL-20 15:03:00 to 07-JUL-20 15:03:00 (MST-7)
Location: BELMONT
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:15:00 to 07-JUL-20 15:15:00 (MST-7)
Location: ELSO
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:10:00 to 07-JUL-20 15:10:00 (MST-7)
Location: ELSO
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Golf ball size hail fell from 410-420pm.

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:10:00 to 07-JUL-20 15:10:00 (MST-7)
Location: ELSO
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:35:00 to 07-JUL-20 15:35:00 (MST-7)
Location: ROUNDUP
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:36:00 to 07-JUL-20 15:36:00 (MST-7)
Location: ROUNDUP
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:36:00 to 07-JUL-20 15:36:00 (MST-7)
Location: KLEIN
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:38:00 to 07-JUL-20 15:38:00 (MST-7)
Location: ROUNDUP
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:45:00 to 07-JUL-20 15:45:00 (MST-7)
Location: DELPHIA
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:13:00 to 07-JUL-20 15:13:00 (MST-7)
Location: ELSO
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in PARK, MONTANA
From 07-JUL-20 13:02:00 to 07-JUL-20 13:02:00 (MST-7)
Location: GRANNIS
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in PARK, MONTANA
From 07-JUL-20 12:50:00 to 07-JUL-20 12:50:00 (MST-7)
Location: LIVINGSTON
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A wind gust of 63 mph was recorded 2 miles west/southwest of Livingston.

Thunderstorm Wind in PARK, MONTANA
From 07-JUL-20 16:07:00 to 07-JUL-20 16:07:00 (MST-7)
Location: CHICO
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A wind gust of 61 mph was recorded 12 miles southeast of Emigrant.

Hail in POWDER RIVER, MONTANA
From 07-JUL-20 17:05:00 to 07-JUL-20 17:05:00 (MST-7)
Location: EPSIE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Hail in POWDER RIVER, MONTANA
From 07-JUL-20 17:35:00 to 07-JUL-20 17:35:00 (MST-7)
Location: BROADUS
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in POWDER RIVER, MONTANA
From 07-JUL-20 17:27:00 to 07-JUL-20 17:27:00 (MST-7)
Location: BROADUS
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in POWDER RIVER, MONTANA
From 07-JUL-20 17:30:00 to 07-JUL-20 17:30:00 (MST-7)
Location: BIDDLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WHEATLAND, MONTANA
From 07-JUL-20 13:10:00 to 07-JUL-20 13:10:00 (MST-7)
Location: TWODOT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in WHEATLAND, MONTANA
From 07-JUL-20 13:40:00 to 07-JUL-20 13:40:00 (MST-7)
Location: JUDITH GAP
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in YELLOWSTONE, MONTANA
From 07-JUL-20 15:50:00 to 07-JUL-20 15:50:00 (MST-7)
Location: SHEPHERD
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in YELLOWSTONE, MONTANA
From 07-JUL-20 15:58:00 to 07-JUL-20 15:58:00 (MST-7)
Location: HUNTLEY
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in YELLOWSTONE, MONTANA
From 07-JUL-20 16:00:00 to 07-JUL-20 16:00:00 (MST-7)
Location: WORDEN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in POWDER RIVER, MONTANA
From 07-JUL-20 18:02:00 to 07-JUL-20 18:02:00 (MST-7)
Location: BELLE CREEK ARPT
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in WHEATLAND, MONTANA
From 07-JUL-20 14:10:00 to 07-JUL-20 14:10:00 (MST-7)
Location: JUDITH GAP
Magnitude: 65.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

An enhanced microburst, around the intersection of 297 and Bercail Road , with winds estimated at 70-75 mph, resulted in a swath about 2 to 3 miles of wind driven rain and hail that sheared grasses and crops. Significant crop damage occurred with grass and wheat fields sheared to the ground. In addition, numerous, large cottonwood limbs with leaves stripped were downed. A small, elevated silo was blown over and minor roof damage occurred to a couple of structures. Highway 287 had pea size to 1/2 inch size gravel blown on it from the shoulder.

Thunderstorm Wind in WHEATLAND, MONTANA
From 07-JUL-20 13:44:00 to 07-JUL-20 13:44:00 (MST-7)
Location: HARLOWTON
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in SWEET GRASS, MONTANA
From 07-JUL-20 15:49:00 to 07-JUL-20 15:49:00 (MST-7)
Location: GREYCLIFF
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Thunderstorm Wind in ROSEBUD, MONTANA
From 07-JUL-20 16:47:00 to 07-JUL-20 16:47:00 (MST-7)
Location: BIRNEY
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in MUSSELSHELL, MONTANA
From 07-JUL-20 15:45:00 to 07-JUL-20 15:45:00 (MST-7)
Location: KLEIN
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

The average hail size was 0.5 inches and covered the ground.

Hail in POWDER RIVER, MONTANA
From 07-JUL-20 17:30:00 to 07-JUL-20 17:30:00 (MST-7)
Location: BROADUS ARPT
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in BIG HORN, MONTANA
From 07-JUL-20 15:25:00 to 07-JUL-20 15:25:00 (MST-7)
Location: KIRBY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CARTER, MONTANA
From 07-JUL-20 18:45:00 to 07-JUL-20 18:45:00 (MST-7)
Location: EKALAKA
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CARTER, MONTANA
From 07-JUL-20 19:12:00 to 07-JUL-20 19:12:00 (MST-7)
Location: BELLTOWER
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Thunderstorm Wind in CUSTER, MONTANA
From 07-JUL-20 18:22:00 to 07-JUL-20 18:22:00 (MST-7)
Location: KINSEY
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Large tree branches fell on I-94 between mile markers 144 and 145.

Thunderstorm Wind in CUSTER, MONTANA
From 07-JUL-20 18:15:00 to 07-JUL-20 18:15:00 (MST-7)
Location: MILES CITY ARPT
Magnitude: 64.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A wind gust of 74 mph was recorded at the Miles City Airport.

Thunderstorm Wind in FALLON, MONTANA
From 07-JUL-20 18:30:00 to 07-JUL-20 18:30:00 (MST-7)
Location: BAKER
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Several trees were uprooted and power lines were downed. The local farm and fleet store had a number of large stock tanks that traveled about 1/4 mile into town taking out a few fences. In addition, power was out in much of the town.

Hail in GOLDEN VALLEY, MONTANA
From 07-JUL-20 14:15:00 to 07-JUL-20 14:15:00 (MST-7)
Location: BARBER
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GOLDEN VALLEY, MONTANA
From 07-JUL-20 15:03:00 to 07-JUL-20 15:03:00 (MST-7)
Location: BELMONT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter