Late in the afternoon of September 19th, a frontal boundary pushed into the Devils Lake to Jamestown (ND) corridor. Due to fairly extensive cloud cover throughout the day, late afternoon temperatures only ranged in the low 60s over the Devils Lake region, to the lower 70s over southeast North Dakota into west central Minnesota. Even though temperatures remained on the cool side, a strong moisture surge occurred. Cloud cover decreased somewhat over southeast North Dakota during the late afternoon, where thunderstorms flared up south of Jamestown. As this large thunderstorm cell moved into southwest Barnes County (ND), it produced a tornado near Litchville. This cell evolved into a larger storm complex, which moved east-northeast through the evening. This storm complex produced large hail, strong winds, and a second tornado along the Norman/Polk (MN) county border in Minnesota.

Thunderstorm Wind in POLK, MINNESOTA
From 19-SEP-17 19:40:00 to 19-SEP-17 19:40:00 (CST-6)
Location: UNION LAKE
Magnitude: 74.00 EG
Reported by: Public

Trees were blown down at a farmstead, some being uprooted.

Thunderstorm Wind in RED LAKE, MINNESOTA
From 19-SEP-17 19:50:00 to 19-SEP-17 19:50:00 (CST-6)
Location: BROOKS
Magnitude: 52.00 EG
Reported by: Public

Numerous four to six inch diameter tree branches were broken down in shelterbelts across southern Poplar River Township. A nearby MNDOT RWIS mesonet station also lost power.

Thunderstorm Wind in POLK, MINNESOTA
From 19-SEP-17 19:59:00 to 19-SEP-17 19:59:00 (CST-6)
Location: FOSSTON MUNI ARPT
Magnitude: 55.00 MG
Reported by: AWOS

The AWOS at the Fosston airport measured the wind gust from the southwest. Shelterbelts in adjacent portions of Brandsvold Township had broken oak branches commensurate with these wind speeds.

Thunderstorm Wind in POLK, MINNESOTA
From 19-SEP-17 20:15:00 to 19-SEP-17 20:15:00 (CST-6)
Location: OLGA
Magnitude: 61.00 EG
Reported by: Public

Several trees were blown down with large tree limbs scattered about.

Thunderstorm Wind in BECKER, MINNESOTA
From 19-SEP-17 21:55:00 to 19-SEP-17 21:55:00 (CST-6)
Location: CORMORANT
Magnitude: 56.00 EG
Reported by: Broadcast Media

Many large tree branches and power lines were blown down around Cormorant Lake, resulting in localized power outages.

Thunderstorm Wind in MAHNOMEN, MINNESOTA
From 19-SEP-17 22:40:00 to 19-SEP-17 22:40:00 (CST-6)
Location: NAYTAHWAUSH
Magnitude: 56.00 EG
Reported by: Broadcast Media

Numerous large tree branches and power lines were blown down around Tulaby Lake and Elbow Lake, resulting in localized power outages.

Thunderstorm Wind in GRANT, MINNESOTA
From 19-SEP-17 22:54:00 to 19-SEP-17 22:54:00 (CST-6)
Location: ELBOW LAKE
Magnitude: 52.00 EG
Reported by: Law Enforcement

A few large tree branches were blown down around town. The peak wind measured at the Elbow Lake airport was 54 mph.

Thunderstorm Wind in OTTER TAIL, MINNESOTA
From 19-SEP-17 23:30:00 to 19-SEP-17 23:30:00 (CST-6)
Location: PARKERS PRAIRIE
Magnitude: 56.00 EG
Reported by: Public

Numerous trees were blown down around town. At least one tree fell on a house.

Thunderstorm Wind in OTTER TAIL, MINNESOTA
From 19-SEP-17 23:25:00 to 19-SEP-17 23:25:00 (CST-6)
Location: HENNING
Magnitude: 52.00 EG
Reported by: NWS Storm Survey

A few four to six inch diameter tree branches were blown down in groves and shelterbelts across east central Henning Township.

Tornado in POLK, MINNESOTA
From 19-SEP-17 18:53:00 to 19-SEP-17 19:01:00 (CST-6)
Location: BELTRAMI
Tornado F-scale: EF1
Property damage: 50.00K
Crop damage: 3.00K
Reported by: NWS Storm Survey

This tornado began in Norman County, about three miles north-northeast of Lockhart, at 650 PM CST. As it crossed into Polk County, about 653 PM CST, debris from the tornado broke windows in a vehicle. The tornado then snapped trees in and around the community of Beltrami and dismantled a metal wrapped pole shed. Peak winds were estimated at 105 mph.

Tornado in NORMAN, MINNESOTA
From 19-SEP-17 18:50:00 to 19-SEP-17 18:53:00 (CST-6)
Location: LOCKHART
Tornado F-scale: EF1
Property damage: 2.00K
Crop damage: 2.00K
Reported by: NWS Storm Survey

This tornado began in Norman County, Minnesota, about three miles north-northeast of Lockhart. It tracked about a mile in Norman County, before it crossed into Polk County, where it continued about another three miles. The tornado ended at 701 PM CST, just past the community of Beltrami, Polk County. Peak winds were estimated at 105 mph.