Patchy dense fog possible early this Wednesday morning – mainly away from Chicago

Fog causes delays on highway and in air

Update 7:15AM CDT...

While visibility lowered to a quarter-mile or less in a few spots early this morning, most of the Chicago area was relatively unaffected by fog this morning. Joliet airport briefly dropped to a quarter-mile visibility between 6 and 7AM and some low-lying areas/along streams or rivers experienced fog. The entire Chicago area should be fog-free by 8 or 9AM.

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With clear skies and light winds, and temperatures and dew points in the middle 30s, conditions appear optimum for dense fog formation early this Wednesday morning. Patchy dense fog will likely develop in scattered parts of the Chicago area – generally away from the city appears most susceptible. If you are traveling – involved in the morning commute, be aware that patches of dense fog may develop in spots, quickly cutting visibility to a quarter-mile or less. Drive carefully.

Current Metro-area visibility (in tenths of a mile)…