Check out this animated satellite image. Run it manually in both directions to get a feel for what is happening. It looks like the two storms are gonna put Chicago in the squeeze.
http://www.ssd.noaa.gov/goes/east/eaus/flash-wv.html
http://weather.rap.ucar.edu/satellite/displaySat.php?region=BWI&itype=wv&size=small&endDate=20121029&endTime=-1&duration=12