CHICAGO -- Gloomy skies dominate Chicago today, with scattered thunderstorms moving across thearea have causing  more than 400 flight cancellations and hour-long delays at O’Hare and Midway Monday.

O’Hare Airport is reporting delays between 45 and 60 minutes for all flights in and out of the airport and more than 400 flights have been canceled. At Midway, a “handful” of flights are delayed 45 minutes and no major cancellations have been reported, according to Karen Pride, Media Relations Director for the Chicago Department of Aviation.

The NOAA National Weather Service is predicting continued thunderstorms tonight consisting of brief heavy downpours, strong possibly “damaging” winds, hail and a heat index of 100 degrees or greater, according to the NOAA Web Site.

Travelers passing through O’Hare or Midway Monday are urged to contact their airline to check the status of their flight.

AccuWeather predicted a high temperature of 91 with a RealFeel high of 97.

Heat exhaustion is the result of spending too much time in the heat, not just too much time in the sun, a release from the governor's office explained.  Exhaustion occurs when a person loses fluids and salts (electrolytes) due to sweating. Symptoms can include dizziness, nausea, light-headedness, severe headache, cool and clammy skin, heavy perspiration, and muscle cramps.  If a person is suffering from heat exhaustion, lay that person down in a cool place with the person’s head lowered and feet raised, and immediately seek medical attention.
 
Similarly, heat stroke is caused by prolonged exposure to high temperatures, even if a person is just sitting or lying in the heat for too long.  Heat stroke can be fatal and should be considered a medical emergency.  Symptoms can include a body temperature of 105 degrees or more, skin is hot to the touch, a red and dry face, headache, loss of consciousness in extreme cases, and seizures.  A person suffering from heat stroke should be placed in a semi-sitting position and sprayed with tepid (not cold) water and cooled with fans.  Medical attention should be sought immediately.
 
To prevent heat exhaustion and heatstroke, according to the governor's office, people should drink plenty of water and other liquids that do not contain caffeine or alcohol, in addition to staying inside air-conditioned buildings and avoiding strenuous activity during the heat of the day.
 
The state has more than 120 facilities that serve as cooling centers, according to the release.  The cooling centers provide a place to stay cool and comfortable during the hot days of summer.  The cooling centers are located at Illinois Department of Human Services (IDHS) offices throughout the state and the seven Illinois Tollway Oases in Chicago.  They are open to the public during regular business hours, so anyone seeking refuge from the heat has a cool place to go when the temperature climbs.

Chicago also operates cooling centers throughout the city, where residents can seek refuge from the oppressive heat. To locate a cooling center, residents can call 311.