The heat stays in place Wednesday afternoon as temperatures are forecast to rise once again into the mid 90s, with the heat index peaking between 100-105 degrees. Southwest winds will remain gusty throughout the day, reaching close to 25 mph during the afternoon.
The majority of Wednesday will be dry, but we may see a little more cloud cover with thunderstorms well west of the Stateline during the first half of the day. As a cold front continues to pass through the Midwest, reaching eastern Iowa and Wisconsin by the late afternoon storms will continue to develop, quickly turning severe during that time. The greatest risk for severe thunderstorms will be in Wisconsin where the highest instability and wind shear will be realized. This could pose a significant risk for supercell thunderstorms, possibly producing a few tornadoes.
The cold front doesn’t look to impact areas further south, including northern Illinois and southern Wisconsin, until later in the evening. While we will still have the instability and wind shear, storms may be weakening some as they remain removed from the greatest forcing in the atmosphere. Having said that, wind and hail would be a concern with the stronger storms as they move through. It looks like our window for storm coverage will be from roughly 7pm in northwest Illinois, through Midnight.
The cold front will pass to our east after Midnight with drier air moving Thursday morning. It’ll remain hot Thursday, but dew point temperatures will be a lot lower and this will help with the overall humidity for the afternoon.