Locally gusty thunderstorms will erupt over the Upper Midwest and sweep through the swath from Chicago to Detroit on Saturday.
The storms will not adversely affect travel in the area, but also outdoor activities. People spending time outdoors should keep an eye out for rapidly changing weather conditions. The timing of the storms could affect Evanston and Champaign, Illinois, and Ann Arbor, Michigan, where tens of thousands of fans will be in attendance at college football during Saturday afternoon.
The most common characteristic of the storms will be sudden torrential downpours and frequent lightning strikes.
To track the rapidly changing conditions and onset of storms, check in with AccuWeather's MinuteCast™, which is a patented minute-by-minute, highly localized precipitation forecast. MinuteCast will keep you informed on exactly when it will start and stop raining at a precise street address or GPS location.
According to Severe Weather Expert Henry Margusity, "The storms also have the potential to produce locally damaging wind gusts and hail."
Seek shelter indoors or in an automobile at the first sign of storms, including if you can hear thunder. Standing under a tree during a storm is dangerous due to the risk of being struck by lightning and the potential for a large limb to crash down with no notice.
The storms will erupt along a strong cool front. Ahead of the front warmth and humidity will surge over the region, which can give the storms a boost in intensity. Temperatures will peak into the 70s to the lower 80s over the region.
Much cooler air will sweep into the region in the storm's wake and can result in a 10- to 20-degree temperature drop in a matter of minutes. The afternoon will end with temperatures in the 60s over much of the swath from northern Illinois to the Lower Peninsula of Michigan.
As the front continues to move along, locally gusty storms will survive into portions of central Illinois to northwestern Ohio and southwestern Ontario during Saturday evening. Cities that could be hit by a Saturday evening storm include St. Louis; Indianapolis; Findlay, Ohio; and London, Ontario.
A second round of gusty thunderstorms may visit parts of the Northeast on Sunday. Thunderstorms are forecast to form in a swath from parts of Virginia and West Virginia to Pennsylvania, New York state and New England.