Heavy rain and warmth will trigger flooding

Winter weather systems typically show both warm and cold faces, and the powerful storm
system sweeping across the Midwest today is no different.
This time around, though, Chicago finds itself on the warm side of the storm. That means
rain, and plenty of it today -- perhaps as much as 2 inches. Melting snow will
contribute the equivalent of an additional rainstorm. Widespread flooding will be the result of
all that water.

"ZERO-ZERO" FOG
The perfect recipe for pea-soup fog: mild, moist air and snow cover. Those ingredients
came together across northern Illinois Friday night and are persisting Saturday morning.
The result: Fog so dense that both vertical and horizontal visibilities in the area were
reduced occasionally to less than 100 feet. It is a "zero-zero" situation.
--By Richard Koeneman, WGN Weather Center Meteorologist