A tornado siren blared in Iowa this afternoon as a funnel cloud could be seen in the backdrop of the famed speedway outside Des Moines. NBC News’ Maggie Vespa reports on the severe weather threats facing millions in the Midwest tonight.

The weather service forecasts a high-humidity environment with scattered thunderstorms developing Sunday afternoon and evening. Slow-moving storm cells could produce localized rainfall amounts of 2-3 inches, with isolated areas potentially receiving up to 4 inches of rain.

A tornado watch has been issued until 11 p.m. Friday for Cook County and most of northern Illinois. Strong storms are expected to hit the Chicago area between 8 p.m. and midnight, the National Weather Service said.

Thousands of people were in the path of a dangerous storm that moved through North Carolina on Wednesday afternoon.

Rain and storms will be possible across all of Alabama on Saturday, but a few severe storms could also be in the mix. Above is the severe weather outlook for Saturday. Areas in dark green in north and north-central Alabama have a Level 1 out of 5 severe weather risk today. Storm Prediction Center

Sand and dust storms affect about 330 million people in over 150 countries and are taking an increasing toll on health, economies and the environment.

The chance of rain will decrease through the evening on Friday in the Philadelphia region as temperatures once again gradually drop back into the low 70s to start off the weekend.