Good afternoon. Illinois. I'm Aaron Jolly. If you drove to work this morning, you probably felt like you were piloting a submarine. Dense fog rolled in overnight and it's sticking around, cutting visibility down to a quarter mile near Chicago and along the lakeshore. Take it slow out there. In the next 24 hours. Here's where things get interesting. Illinois is running two completely different weather programs today. Down in Chicagoland, you're stuck with that fog and clouds, barely scraping 39 degrees. Drive south to Central Illinois and suddenly it's a different season — mostly cloudy but hitting 61 degrees. That's a 22 degrees split across the state. Up north, the fog clears by mid-afternoon and you'll reach 50 degrees. Tonight, that fog comes roaring back. A warm front is lifting north. And after sunset, expect visibilities to drop below a mil ...