Entire Chicago area under a Dense Fog Advisory until later this morning
CHICAGO — The Dense Fog Advisory has been expanded to include all of the Chicago area across northeast Illinois and northwest Indiana this Tuesday morning. We are now part of an extensive area of fog with patches of visibility a quarter-mile or less that extends all the way from Arkansas northeast into Wisconsin (see gray-shaded area on highlighted map above). Individuals traveling this morning will likely encounter pockets of very poor visibility, so be prepared for sudden decreases in ability to see for any distance.
Cold air and strengthening northwest winds will be moving into our area from the west later this morning, and as this happens the temperature/dewpoint spread which has closed to a degree or less at most locations,will widen, allowing the visibility to improve dramatically from west to east.