EF1 tornado in Otter Tail County, Minnesota

This tornado tracked briefly to the north-northeast before a wet rear-flank downdraft overtook it as viewed and recorded by multiple storm chase teams. A second and more powerful tornado eventually formed from the parent supercell thunderstorm and impacted the the community of Wadena. Very heavy rains and damaging downdraft winds obscured the overall tornado path. However large tree limbs were broken down and smaller trees were uprooted by the event suggesting peak winds to 90 mph.

Conditions were ripe by the afternoon of the 17th for a major severe weather outbreak. A surface low had moved into east central North Dakota with an occluded front extending to the southeast. Warm and humid air was in place ahead of the front, with a much drier airmass pushing in behind it. The 500mb low was located over northwest North Dakota with a nice southwest to northeast upper jet pushing into eastern North Dakota. Two lines of convection formed by late afternoon, one from Roseau County down toward Eastern Otter Tail County and the other over east central North Dakota. Nearly all the cells that formed took on a classic hook shape with rotation very evident on radar imagery. Multiple tornado warnings were issued before the event wound down by mid evening. The strongest tornadoes were determined to be EF4 tornadoes, two in west central Minnesota and one in northeast North Dakota.