Models have continued to show warm temperatures next week across the Midwest and Great Lakes. Upper-level ridging is expected to take place Sunday into Monday, which will be accompanied by southerly flow. That will usher warm air all the way into the Dakotas and Minnesota early in the week. That warm air will reach northern Illinois and southern Wisconsin by Monday in the form of high temperatures in the lower 80's, which would put the area about 5-10° above average. The epicenter of the heat won't reach this far north, but there will likely be temperatures in the upper 80's and lower 90's to our south and west. In fact, some temperatures on Sunday and Monday could approach 10-20° above average in the Plains and Missouri Valley regions.
Warmth looks poised to remain intact through Thursday, but it will be pushed south on both Tuesday and Wednesday. That will cut the lower 80's into upper 70's to perhaps 80° for Tuesday and Wednesday. As a cold front gathers steam in the Plains on Wednesday, southerly flow will again send well-above average temperatures into the Stateline on Thursday. That will again push high temperatures into the lower 80's for much of the area.