Rain, Wind, Thundersnow -- Thursday Promising to Be a Wild Weather Day

Updated at 2:45 p.m. Dec. 20

The Chicago Tribune is reporting that 500 flights have already been cancelled and more than 700 are delayed at O'Hare airport as the Chicago area braces for snow.

The snow is expected to hit Chicagoland around 3 p.m., with the worst road conditions between 5 and 9 p.m.

To stay up to date on local road conditions, residents can check out the Illinois Department of Transportation's "Getting Around Illinois" website, or click here for Patch's real-time traffic updates.

Posted at 6 a.m. Dec. 20

Karen Sorensen contributed to this report

Hang on to your hat! It's going to be one crazy weather day Thursday.

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It will start with occasional rain and temperatures reaching 45 by 11 a.m., according to the forecast for this area by the National Weather Service, based in Romeoville. By late afternoon, though, temps will be plummeting to 35 and a stong wind from the northwest -- with gusts ranging from 25 to 60 mph -- will kick in, forecasters say.

Snow accumulation could reach two to six inches, with heavier snow occurring overnight. Temps will fall even further, down to about 23 by Friday morning, the forecast says.

A winter storm watch will be in effect early Thursday evening throughout the night, with a chance of thunderstorms. A winter storm watch "means there is a potential for significant snow, sleet or ice accumulations that may impact travel." The wind could cause white-out conditions, the forecast says.

The weather service is still not predicting how much accumulation we might receive locally; generally, it could be as much as six inches in the north and northwest suburbs and possibly two to three inches to the south.

For Friday and the rest of the weekend, expect upper 20s to low 30s during the day and 17 to 22 degrees at night, forecasters say.