Extreme Heat Watch Issued: Heat Index Of 115 Possible In Illinois

ILLINOIS — Heat and humidity will start to build on Tuesday, bringing dangerous heat on Wednesday and Thursday to the Chicago area, according to the National Weather Service.

An extreme heat watch has been issued for Winnebago, Boone, McHenry, Lake, Ogle, Lee, DeKalb, Kane, DuPage, La Salle, Kendall, Grundy, Kankakee, Livingston, Iroquois, Ford, Will and Cook counties. The watch will be in effect from Wednesday morning through Thursday evening, the weather service.

Monday will be the most pleasant day of the week with a high of 84, and humidity will start to build on Tuesday, which will have a high of 87.

Then, on Wednesday and Thursday the high for both days is 98, but the peak heat index value is 115 degrees, according to the weather service.

Storms could bring relief from the heat by late Friday, but if storms are slow to arrive, then heat will continue into Friday, according to the current forecast. Friday will have a high of 90.

"The chances for stormy weather then returns at the end of the week as a cold front approaches the region," the weather service said.

The weather service provided some advice for staying cool in extreme heat including:

• Never leave anyone alone in a closed car.
• Use air conditioners and stay in the shade.
• Drink plenty of water, even if you're not thirsty.
• Wear loose-fitting, light-colored clothing.

Here is a more detailed look at the daily forecast, per the weather service:

MONDAY: Widespread haze before noon. Mostly sunny, with a high near 84. East wind around 10 mph.

MONDAY NIGHT: Partly cloudy, with a low around 66. East wind 5 to 10 mph.

TUESDAY: Mostly sunny, with a high near 87. South southeast wind around 10 mph, with gusts as high as 15 mph.

TUESDAY NIGHT: Partly cloudy, with a low around 71. South southeast wind 5 to 10 mph, with gusts as high as 15 mph.

WEDNESDAY: Sunny and hot, with a high near 95. South southwest wind 10 to 15 mph, with gusts as high as 20 mph.

WEDNESDAY NIGHT: Mostly clear, with a low around 76.

THURSDAY: A 20 percent chance of showers and thunderstorms after 1 p.m. Sunny and hot, with a high near 96.

THURSDAY NIGHT: A chance of showers and thunderstorms. Mostly cloudy, with a low around 73.

FRIDAY: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1 p.m. Partly sunny, with a high near 89.

FRIDAY NIGHT: A chance of showers and thunderstorms. Mostly cloudy, with a low around 70.