Tornado sirens go off in multiple Chicago suburbs, and here’s why

Residents in multiple Chicago suburbs reported tornado sirens going off during Thursday’s storms, but why did they without a tornado warning issued?

According to the National Weather Service, there were no active tornado warnings in the Chicago area as of 7 p.m., but there were several severe thunderstorm warnings in effect.

Despite the lack of tornado warnings, sirens did go off in several locations, including in Barrington and Elgin, according to residents.

So what gives?

According to the NBC 5 Storm Team, while tornado sirens are sounded when there is a warning issued, either because a tornado is on the ground or because rotation has been detected within a thunderstorm, some municipalities will sound sirens when there is a threat of a tornado as well.

Several of the NWS alerts, including one for McHenry, Kane and DeKalb counties, were tagged as “tornado possible” storms, meaning that while there wasn’t strong enough rotation to issue a warning, there was a possibility that the storms could spin up a tornado quickly.

Therefore, the sirens were sounded to alert residents to that possibility.

The severe weather threat is going to continue into the evening, with a tornado watch issued for most of the Chicago area until 11 p.m.

Stay tuned to the NBC Chicago app for real-time weather alerts sent to your phone, including new watches and warnings.