Forecasters are warning 63 million people in the central U.S. to have an eye out for bad weather this week as colliding air masses threaten to generate high winds and possibly tornadoes.
The threat Wednesday stretches from San Antonio to Chicago to Cincinnati.
Missouri, southern Illinois and northern Arkansas face the greatest severe weather threat.
The Storm Prediction Center said Monday that the storms' severity would be dictated by how much warm, humid air can funnel into the area before a cold front approaches from the west. It was too early to pinpoint where the strongest storms might hit.
November storms aren't unusual, but the nation most often sees its worst storms in the spring. This year, there have been 10 deaths from tornadoes, but none since May.
The National Weather Service warned that storms with heavy rain and strong winds are expected in the Chicago area Wednesday night, with some thunderstorms becoming strong to severe.
The "very strong winds" could cause minor damage and be powerful enough to "toss lightweight objects and cause difficult travel."
Wind gusts of up to 50 mph are also expected Thursday ahead of a big temperature cool down. Highs will sit in the low-50s Thursday before falling into the mid-40s by Friday.
There is a chance the area could see a few flurries Friday as well.