Update 5:30PM CST…
Showers and a few embedded thunderstorms will spread north and east across northeast Illinois into southern Wisconsin and northwest Indiana this Monday evening along and ahead of a cold front moving through from the west. Spotty small hail and wind gusts to 40 mph+ are possible with some of the stronger storms.
This weather is driven by a center of low pressure that will move through northern Illinois tonight into Lower Michigan early Tuesday. Winds will shift from south to southwest, eventually to the west and then northwest later tonight. Colder air will feed into our area behind the low pressure with rain becoming mixed with and eventually changing over to wet snow. A little snow accumulation could occur early Tuesday, especially to the north in counties adjacent to the IIlinois-Wisconsin state line.
Current regional weather radar mosaic…
Update 9:30AM CST…
The Flood Advisory has ended, as a warm front has surged north of Chicago taking the band of showers and thunderstorms with it. Rainfall area-wide generally ranged in the half-inch to three-quarter- inch range with the highest early report 0.92-inch at Downers Grove. There still may be ponding in low spots or poorly drained areas, so beware of the possibility of water over or on portions of roadways.
Temperatures should warm well into the 50s this afternoon before another round of showers occurs along and ahead of a cold front that should move through later this afternoon/early evening.
Update 5:50AM CST…
The dense Fog Advisory ends at 6AM CST this Monday morning, however adverse/dangerous driving conditions will continue until at least mid-morning due to a wide swath of shower/thunderstorm downpours moving over northeast Illinois into northwest Indiana where a Flood Advisory has been issued (green-shaded area on the highlighted map). These unseasonably heavy rains on top of frozen soils will cause ponding/flooding on roads/highways and poorly drained underpasses and other low-lying areas. Assume there will be slowed driving conditions due to the restricted visibility in heavier rain, and be aware of potential standing water on roadways/streets.
CHICAGO — Dangerous driving conditions are expected as a Dense Fog Advisory goes into effect for the entire Chicago area Sunday night (grey-shaded area on the map below) calling for frequent visibility ranging from a quarter-mile to a matter of a few feet.
If traveling, be aware of rapidly changing visibility and dangerous driving conditions Sunday evening, and into the overnight hours.
Latest area airport visibility in tenths of a mile: