An Excessive Heat Warning has been issued for the Chicago area for Wednesday and Thursday.

Intense heat and humidity will cause potentially dangerous conditions.

Peak afternoon heat indices of 108 to 113 degrees are expected.

Full forecast details and more at the WGN Weather Center blog

Chicago cooling centers have opened to help residents stay safe and cool.

CPS has activated its Heat Action Plan and has urged teachers to keep rooms cool by drawing shades and turning off unused computers. CPS will also hold recess and physical education indoors. 

5:15 p.m. — Tom Skilling’s Evening Forecast

1:45 p.m. Saint Sabina Catholic Church is helping some South Side residents enjoy a cold, refreshing reprieve from the heat and handing out water.

12:05 p.m. — Tom Skilling reports we’re headed for the predicted record breaking 99-dgree high today. “Some areas around Chicago may top out at 100-degrees, something which has happened officially in the city only 62 times before today. Heat indices approaching 115-deg–higher in some locations–will be within reach Wednesday and Thursday.”

Noon — Current heat index

11:17 a.m. — The heat index at both airports is currently sitting at a toasty 107° WGN’s Bill Snyder reports.

11 a.m. — An Excessive Heat Warning is now in place for Cook, DuPage, Grundy, Kane, Kankakee, Kendall, La Salle, Lake, McHenry and Will counties in Illinois and Jasper, Lake, Newton and Porter counties in Indiana.

Latest warnings and watches from the National Weather Service.

10:35 a.m. The National Weather Service in Chicago reports the due point has reached 80 degrees at O’Hare airport. It is the first 80 degree dew point in Chicago since July 30, 1999.

9 a.m. — Thursday will see good deal of sunshine, intensely hot and humid with haze. Sharp cooling later in the day begins on the North Shore and reaches across the city by and during the evening—but not before a potential record high of 101 and a peak heat index around 112.

Looking ahead:

FRIDAY: Partly cloudy, hazy and humid—but not as warm. A few scattered afternoon and nighttime t-storms possible, but with only 20 to 30% coverage. High 84 — but  lower lakeshore.

SATURDAY and SATURDAY: Windy from the northeast and noticeably cooler. Partly sunny with humidities trending lower. High Saturday 74; Sunday’s high 76—but mid 60s to low 70s along Lake Michigan.

MONDAY: Partly sunny and warmer. Chance of nighttime t-storms. High 83.

TUESDAY AND WEDNESDAY: A good deal of sunshine—just mixed clouds, windy and cooler again. High 76 Tuesday and 79 Wednesday—but cooler due to north/northeast winds along Lake Michigan.