Summer Thunderstorms Threaten Millions in Upper Midwest and Northern Plains

More than 3 million people are under the threat of dangerous storms across the Upper Midwest and the northern Plains this week. Read on for a detailed look at the timing, locations, and expected impacts associated with this volatile weather maker.

Severe Weather Impacts to Persist Through Thursday for Northern U.S.

Days of severe storms are forecast to train over the same areas of the northern Plains and into the Upper Midwest for much of the week. The classic summer storm line will bring the chance of damaging winds, heavy rain, and flash flooding through at least Thursday.

The next round of storms will follow the lead of Monday's severe weather event. The Storm Prediction Center (SPC) out of the National Oceanic and Atmospheric Administration (NOAA) said that it fielded at least six preliminary tornado reports on this day alone.

The thunderstorms and resulting tornadoes wreaked havoc across northern Minnesota. Emergency shelters for displaced residents are now open in the community of Detroit Lakes. The National Weather Service (NWS) said that it expects tornado survey crews to be on the ground in Detroit Lakes by Tuesday afternoon.

Farther to the east, residents of Walworth County, Wisconsin, are still cleaning up the mess left by a wave of storms that hit the region on Friday, July 3. Forecasters are warning that this zone of the Upper Midwest will be under an increased risk of flash flooding later this week because so much of the ground is still saturated

Most of the thunderstorm activity in the coming days will ignite in the afternoon hours due to the natural heating of the day. These storms are most likely to form around the ridge of high pressure tethered over the central U.S.

The atmospheric setup will support the development of the "training" effect throughout the Upper Midwest, acting like boxcars on a train track. Like a train, the individual thunderstorm cells will roam over the same swath of land in a line.

Timing and Location of This Week's Storm Activity

NOAA's Weather Prediction Center (WPC) recently issued a Level 2 out of 4 flash flood threat for the eastern flanks of the Dakotas and central portions of Minnesota and Wisconsin. This threat is in place through Wednesday morning. In addition to the heavy rain on tap, the storms will also pack winds up to 75 mph.