Dense Fog Advisory

* WHAT...For the Extreme Heat Warning, dangerously hot conditions with peak heat index values 110 to locally over 115 degrees expected. For the Dense Fog Advisory, visibility less than one quarter mile in dense fog.

* WHERE...Livingston, De Kalb, La Salle, Lee, Ogle, Winnebago, and Grundy Counties.

* WHEN...For the Extreme Heat Warning, until 9 PM CDT this evening. For the Dense Fog Advisory, until 8 AM CDT this morning.

* IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events. Low visibility could make driving conditions hazardous.