Hot, steamy air lying to our south and west Monday afternoon helped fuel potentially severe thunderstorms across parts of the Midwest. Temperatures as high as the mid-90s across much of Missouri, combined with dew points in the mid-70s to produce heat indices of around 110 degrees. Meanwhile, under cloud covered skies over northern Illinois, readings held in the low 80s. Storms focused along a front separating these differing air masses, leaving parts of northwest and central Illinois in an enhanced risk of severe weather, including possible tornadoes. The Chicago area was slated for downpour-producing thunderstorms. The system that caused the rough weather Monday evening will move south and east of the area, ending the threat of severe storms. However, enough residual moisture and instability could fuel scattered afternoon and evening showers and thunderstorms both Tuesday and Wednesday.