'Ring of fire' conditions expected as heat, humidity create weather like 'air you can wear'

Chicago will once again face a “ring of fire” pattern of storms this week, though it’s less likely to be as severe as the one that spawned more than two dozen tornadoes earlier in the month, the National Weather Service said.

Heat indices of more than 100 degrees are also expected later in the week.

Brett Borchardt, a senior meteorologist with the National Weather Service, said this week’s storms had a similar “ring of fire” pattern — which is when storms form around a heat dome. A similar pattern produced a complex of storms known as a derecho on July 15 that led to 31 tornadoes moving through the Chicago area.

However, Borchardt cautioned that this week's storms may not be of similar severity. He said damaging winds are the main concern, though tornadoes are possible.

“At this point we don’t see any signs that the storms will be as bad as a few weeks ago,” Borchardt said. “But it’ll still be a pattern you have to stay up to date on the forecast.”

Wednesday and Thursday are slated to be the hottest days of the week, with temperatures in the low 90s, though humidity will bring heat indices up to 105 degrees in some parts of the area, Borchardt said. He says it will be like “air you can wear.”

The city's cooling centers will be open from 9 a.m. to 5 p.m. this week in response to the anticipated heat, though the Garfield Center will be open 24 hours a day. Here are the locations:

• Englewood Center – 1140 W. 79th St.
• Garfield Center – 10 S. Kedzie Ave.
• King Center – 4314 S. Cottage Grove
• North Area Center – 845 W. Wilson Ave.
• South Chicago Center – 8650 S. Commercial Ave.
• Trina Davila Center – 4312 W. North Ave.

City officials have also previously suggested people make use of other city facilities to keep cool, such as Chicago Public Library locations, Chicago Park District fieldhouses and Chicago Police Department district stations. Residents can find the nearest cooling centers by visiting this site or calling 311.

If thunderstorms continue throughout the day Wednesday and Thursday, as they have a chance to, it could bring down temperatures Borchardt said. The heat “primes” the atmosphere for storms, and humidity can raise the risk of creating damaging winds.

“Stay up to date on the forecast, limit the amount of time in the sun and stay hydrated, but also keep an eye to the sky,” Borchardt said. “Sometimes storms develop very quickly when it's this hot outside, so be prepared to move indoors if you hear thunder or see clouds start to tower on top of you.”