The National Weather Service has issued a flood watch for Cook, DuPage and Kane counties, and virtually the entire Chicago area, from 6 p.m. Tuesday, Jan. 29, until 4 a.m. Wednesday, Jan. 30.
Showers and thunderstorms will continue to spread across Northern Illinois and Northwest Indiana this afternoon, with rain persisting through the night. Precipitation of 1.5 to 2 inches is likely, with some areas receiving more.
"Much of the area continues to have frozen ground, with only the top few inches of soil having thawed," according to the weather service. "(This) could lead to a majority of the rainfall becoming runoff and resulting in a rapid rise to area streams and rivers."
Temperatures will begin dropping in the early morning hours Wednesday, reaching the mid-30s by noon. The rain is then expected to turn to snow for the rest of the day, tapering off around midnight.
On Thursday, expect a high 17 degrees under mostly cloudy skies; overnight low 4 degrees.
On Friday, temperatures are expected to hold steady at about 19 degrees day and 16 degrees at night.
A slight warmup is coming Saturday, with a high of 30 and a low of 22 degrees, accompanied by a 30 percent chance of snow. Sunday could reach 40, with no chance of precipitation.
Expect dry, cloudy and cold conditions next week.