CHICAGO (CBS) -- Patchy fog will continue in the Chicago area Saturday evening. Showers or drizzle will affect the southern half of the area Saturday night, then quickly move on. 

A dense fog advisory has been issued for northern and central Cook County and Lake County, Illinois, as well as Lake and Porter counties in Indiana until midnight Saturday. Visibility is expected to be one quarter mile or less due to dense fog near Lake Michigan, according to the National Weather Service Chicago. 

Clouds will linger through Friday. 

FORECAST: 

SATURDAY NIGHT: Drizzle and showers (mainly south). LOW: 33

SUNDAY: Mostly cloudy. HIGH: 41

EXTENDED: Highs remain in the low 40s through end of week. Clouds are expected all week, with a few peeks of sunshine.