An upper trough moving east into the Pacific Northwest and bumping into a warm and unstable airmass over eastern Montana triggered severe thunderstorms mainly after sunset. Heavy rain also occurred in an area that produced flash flooding.

Thunderstorm Wind in MCCONE, MONTANA
From 01-JUL-10 19:55:00 to 01-JUL-10 19:55:00 (MST-7)
Location: FT PECK LAKE HANDAR
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Fort Peck Handar Observation Site reported this wind gust above the intake buildings at Fort Peck Dam.

Thunderstorm Wind in VALLEY, MONTANA
From 01-JUL-10 19:58:00 to 01-JUL-10 20:01:00 (MST-7)
Location: GLASGOW
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Brief severe winds caused small tree branches to break off of trees.

Thunderstorm Wind in VALLEY, MONTANA
From 01-JUL-10 20:10:00 to 01-JUL-10 20:10:00 (MST-7)
Location: NASHUA
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Severe winds blowing through town with yard and garbage debris blowing throughout the city.

Thunderstorm Wind in MCCONE, MONTANA
From 01-JUL-10 21:16:00 to 01-JUL-10 21:16:00 (MST-7)
Location: CIRCLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Small tree branches breaking out of trees in town.

Thunderstorm Wind in MCCONE, MONTANA
From 01-JUL-10 21:40:00 to 01-JUL-10 21:40:00 (MST-7)
Location: CIRCLE
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

One inch diameter tree limbs broken off.  Larger dead tree limbs of 6 to 8 inches broken off.

Thunderstorm Wind in VALLEY, MONTANA
From 01-JUL-10 20:45:00 to 01-JUL-10 20:50:00 (MST-7)
Location: LARSLAN
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

NWS Employee estimated wind at 65 to 70 mph. Strong wind damaged sliding glass door 6 miles east of Larslan.

Thunderstorm Wind in PRAIRIE, MONTANA
From 01-JUL-10 21:28:00 to 01-JUL-10 21:28:00 (MST-7)
Location: FALLON
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Mesonet site W7PG-11 recorded the wind gust.

Flash Flood in MCCONE, MONTANA
From 01-JUL-10 20:10:00 to 01-JUL-10 21:10:00 (MST-7)
Location: BROCKWAY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Neighbor of a trained spotter reported two feet of water flowing over Highway 200 between Circle and Flowing Wells Rest Area.

Lightning in VALLEY, MONTANA
From 01-JUL-10 19:59:00 to 01-JUL-10 19:59:00 (MST-7)
Location: GLASGOW
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Tree hit by lightning on Second Ave North in Glasgow landed on a car.

Thunderstorm Wind in MCCONE, MONTANA
From 01-JUL-10 21:10:00 to 01-JUL-10 21:10:00 (MST-7)
Location: BROCKWAY
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter (located 1 mile north of the Flowing Wells Rest Area) reported 58 mph wind gust.

Thunderstorm Wind in MCCONE, MONTANA
From 01-JUL-10 21:32:00 to 01-JUL-10 21:32:00 (MST-7)
Location: CIRCLE
Magnitude: 52.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

Awning torn off of a home and flipped up on the roof by severe winds.

Thunderstorm Wind in VALLEY, MONTANA
From 01-JUL-10 19:59:00 to 01-JUL-10 20:02:00 (MST-7)
Location: GLASGOW INTL AIRPORT (KGGW)
Magnitude: 51.00 MG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: ASOS

A shelf cloud came through Glasgow producing brief winds of 55 to 60 mph.  A forty foot section of metal roof off of an airport hanger building was peeled back and blown approximately 75 yards to the north.  A large highway sign was blown off and shredded  along Highway 2 east of Glasgow.

Thunderstorm Wind in RICHLAND, MONTANA
From 01-JUL-10 22:23:00 to 01-JUL-10 23:39:00 (MST-7)
Location: SIOUX PASS DOT
Magnitude: 51.00 MG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Mesonet

Spotter 14 miles south-southeast of Culbertson estimated a wind gust of 60 mph at 2223 MST which blew over a 15 foot grain hopper. At 2339 MST, Sioux Pass DOT sensor recorded a wind gust of 58 mph.

Thunderstorm Wind in GARFIELD, MONTANA
From 01-JUL-10 18:56:00 to 01-JUL-10 18:56:00 (MST-7)
Location: JORDAN AIRPORT (KJDN)
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A spotter in the Hell Creek Recreation Area reported strong winds ahead of the thunderstorms.