Motorists in the western suburbs are being advised to use extra caution while driving on Thursday night, as a dense fog advisory is in effect for several northern Illinois counties.
According to the National Weather Service, the advisory is now in effect for DeKalb, LaSalle, Kendall and Grundy counties, and will remain in effect until 4 a.m.
Outside of the NBC 5 viewing area, Lee, Ogle, Livingston and Ford counties are also impacted by the advisory.
The advisory originally ended at midnight, but was extended to 4 a.m. in the impacted area.
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The NWS also added southern Will County and all of Kankakee County to the advisory.
According to forecasters, visibility will be reduced to one-quarter mile or less in the affected areas. Falling temperatures could also cause issues, as patchy slick spots could develop on roadways when the temps drop below the freezing mark, according to NWS.
Forecasters are urging motorists to use their low-beam headlights, to drive slower than normal and to increase following distances in the affected counties.