AccuWeather Global Weather Center - AccuWeather reports rounds of thunderstorms, including severe weather, will affect the Midwest this weekend into Monday, ahead of a push of unseasonably cool air.
While the effect of the July sun and warm landscape will cancel some of the cool air, it will become surprisingly cool during what is typically the hottest time of the year.
According to AccuWeather Meteorologist Carl Erickson, "The pattern is reminiscent of a major polar plunge that occurred this past winter, which was referred to as the Polar Vortex."
The pattern will deliver multiple days with high temperatures in the lower 70s in Chicago and Detroit and even a day or two with highs in the 60s in Minneapolis and other parts of the Upper Midwest.
At night, temperatures could challenge record lows. Temperatures will drop into the 50s at night in these cities and others and will dip into the 40s in some of the suburbs and rural areas.
The cooler air will move in aloft before reaching ground level. As this happens, an unstable atmosphere will trigger episodes of thunderstorms, some of which will be severe in parts of the region.
The first episode will fire over portions of the northern and central Plains to the Upper Midwest into Friday.
On Friday, the storms in parts of eastern Wyoming and from northeastern Colorado to Nebraska and Minnesota will bring the potential for damaging wind gusts and large hail.
On Saturday, the severe weather threat will shift eastward and southward over the Central states. The storms are forecast to extend across portions of Kansas, northern Missouri, Illinois, Indiana, Michigan and southern Wisconsin.
Once again, the major threats will be damaging wind gusts and hail.
The severe storms spanning Saturday into Sunday could reach the metro areas of Kansas City, Missouri; Chicago, St. Louis, Indianapolis and Detroit with the risks of power outages, property damage and travel disruptions.
Sunday and Monday, the threat of severe weather will continue in portions of the Ohio Valley and will ramp up in the Northeast.
After the cool air takes root in the Midwest, waterspouts will be a threat to boaters, fishing and beach interests over the southern portion of the Great Lakes.
By Kevin Byrne, Staff Writer for AccuWeather.com