Rush hour might be quite a bit slower than usual Friday. 

The National Weather Service (NWS) has a Winter Storm Warning in effect Friday until midnight and is predicting 4 to 7 inches of snow to accumulate by then.

Click here to read the advisory.

NWS is warning that snow will fall at a rate as high as one inch per hour during the day, leading to decreased visibility for drivers. NWS predicts a "particularly treacherous" Friday afternoon commute and warns flights out of O'Hare and Midway could be disrupted.

Temperatures Friday will consistently hover in the low 20s and winds won't be a huge factor, staying between 5 and 10 mph. 

To keep up on any schools or other facilities closing due to the weather, visit the Emergency Closing Center website.