The 12th was a hot and humid day across eastern North Dakota and the northwest quarter of Minnesota. Afternoon temperatures topped out in the 80s with dew points around 70F. A weak convergent boundary, which by late afternoon extended from near Roseau south-southwest to a surface low near Aberdeen, South Dakota, provided the focus for the initial thunderstorm development. Several reports of large hail and damaging winds were received, but the most extensive damage occurred in the Thief River Falls, Minnesota, area.

Thunderstorm Wind in BELTRAMI, MINNESOTA
From 12-JUL-13 19:05:00 to 12-JUL-13 19:05:00 (CST-6)
Location: WASKISH
Magnitude: 60.00 EG
Reported by: COOP Observer

Several dead trees were blown down over a road. Very heavy rainfall was also reported.

Thunderstorm Wind in WILKIN, MINNESOTA
From 12-JUL-13 20:44:00 to 12-JUL-13 20:44:00 (CST-6)
Location: NASHUA
Magnitude: 65.00 EG
Reported by: Emergency Manager

A large cottonwood tree was blown over between Nashua and Tintah.

Thunderstorm Wind in GRANT, MINNESOTA
From 12-JUL-13 21:16:00 to 12-JUL-13 21:16:00 (CST-6)
Location: ELBOW LAKE
Magnitude: 55.00 EG
Reported by: Public

Several six to eight inch diameter tree branches were blown down in Elbow Lake.

Thunderstorm Wind in PENNINGTON, MINNESOTA
From 12-JUL-13 17:00:00 to 12-JUL-13 17:05:00 (CST-6)
Location: THIEF RIVER FALLS
Magnitude: 70.00 EG
Reported by: Law Enforcement

Light poles, power lines, and hundreds of trees were blown down. Peak winds across the central part of town were estimated at 60 to 80 mph.

Thunderstorm Wind in PENNINGTON, MINNESOTA
From 12-JUL-13 17:05:00 to 12-JUL-13 17:07:00 (CST-6)
Location: (TVF)THIEF RVR FALLS
Magnitude: 87.00 EG
Reported by: NWS Storm Survey

Significant wind damage occurred on the southeast side of Thief River Falls. Numerous roofs were damaged, a motor home was flipped, and billboards were bent or broken. Several trailer homes were damaged and one was flipped. Several garages had roofs removed or were collapsed. Peak winds were estimated at 95 to 105 mph and occurred for a couple of minutes.

Thunderstorm Wind in PENNINGTON, MINNESOTA
From 12-JUL-13 17:10:00 to 12-JUL-13 17:10:00 (CST-6)
Location: (TVF)THIEF RVR FALLS
Magnitude: 105.00 EG
Reported by: NWS Storm Survey

Numerous large hardwood trees were uprooted or had trunks snapped along the banks of the Red Lake River. Peak winds were estimated at 100 to 110 mph.

Thunderstorm Wind in PENNINGTON, MINNESOTA
From 12-JUL-13 17:15:00 to 12-JUL-13 17:15:00 (CST-6)
Location: HAZEL
Magnitude: 100.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Extreme winds snapped a dozen wooden power poles, uprooted numerous trees and caved in or otherwise demolished several large capacity steel grain bins and other outbuildings at a farm site. The tree damage extended across much of southern Silverton and northern Smiley townships. Peak winds were estimated at 110 to 120 mph.

Thunderstorm Wind in PENNINGTON, MINNESOTA
From 12-JUL-13 17:20:00 to 12-JUL-13 17:20:00 (CST-6)
Location: MAVIE
Magnitude: 52.00 EG
Reported by: Public

Several large tree branches and limbs were blown down in shelterbelts across southern Clover Leaf and northern Kratka townships. A nearby NDAWN wind sensor measured peak winds of 55 mph.

Hail in ROSEAU, MINNESOTA
From 12-JUL-13 15:34:00 to 12-JUL-13 15:34:00 (CST-6)
Location: BADGER
Magnitude: 0.75 
Reported by: Trained Spotter

Heavy rainfall was also reported.

Thunderstorm Wind in BELTRAMI, MINNESOTA
From 12-JUL-13 18:30:00 to 12-JUL-13 18:30:00 (CST-6)
Location: PONEMAH
Magnitude: 55.00 EG
Reported by: Public

Numerous three to five inch diameter tree branches were broken down around the area. There was also quite a bit of dime to nickel size hail.