Chicago weather: Spring storm to bring heavy downpours, isolated thunderstorms

A spring storm system moves into the Chicago area Tuesday, bringing waves of heavy downpours, isolated thunderstorms, lightning, sharply dropping temperatures and even some light snow.

The weather forecast comes as other parts of the U.S. is also set to see severe storms and even tornadoes, including parts of New Orleans, Texas, Alabama and New Mexico. In the Midwest, the storm could bring a band of heavy snow to Northeast Iowa, southeast Minnesota and central Wisconsin, the National Weather Service said.

As of 5 a.m. Tuesday, Illinois weather radar showed moderate-to-heavy rain and lightning passing through Grundy, LaSalle, Will and Kankakee counties and spreading into Northwest Indiana.

By the morning rush hour commute, the rain will move north and become widespread, NBC 5 Meteorologist Alicia Roman said.

"Really filling in across the mid-to-late morning hours," Roman said, with NBC 5 traffic reporter Kye Martin already reporting a wet, gloomy commute.

On-and-off showers will continue all day, Roman said, with heavy downpours at times for the afternoon and evening commutes.

"Take the umbrella with you," Roman warned. "Most areas will see a pretty decent soaking."

The soaking rainfall could lead to instances of ponding and localized flooding, according to the NWS. Chicago-area residents were asked to delay showers and curb water usage as part of an "Overflow Action Alert."

Late Tuesday into early Wednesday, there could be a break in the rain, Roman said. And though temperatures will remain above-average Tuesday with highs near 50, cold air moving in Wednesday afternoon means plummeting temperatures.

Light snow possible

Rain will continue Wednesday morning, Roman said, with temperatures topping out around 50 degrees in the mid-morning hours. They won't stay that way for long.

"By 11 a.m., temperatures will quickly drop," Roman said of Wednesday. "And turning pretty gusty, with winds of 30-40 miles-per-hour."

Around 3 p.m., rain will gradually change to light snow, with temperatures in the 30s.

"Maybe just a dusting," Roman said, though the drop in temperatures could lead to slick roads from all the rain.

Thursday, will but cooler but brighter, Roman said, with highs in the low 40s. By Friday, chances of a snow-rain mix was back in the forecast, Roman said.