UPDATE: Severe Thunderstorm Passed, Flood Warning Ended

Update, 6:05 p.m., Saturday, Aug. 4

A massive thunderstorm, covering about half of Illinois and much of Wisconsin, has passed over the area and is continuing on east.

Power outages have affected hundreds of customers throughout the south suburbs.

The Taste of Orland Park has reopened for attendees as of 6 p.m. Saturday.

While severe storm and flood warnings have ended, the National Weather Service is maintaining an air quality warning until midnight.

According to the NWS:

AN AIR POLLUTION ACTION DAY IS DECLARED WHEN WEATHER CONDITIONS ARE SUCH THAT WIDESPREAD OZONE AND OR PARTICULATE LEVELS ARE EXPECTED TO BE AT OR ABOVE THE UNHEALTHY FOR SENSITIVE GROUPS CATEGORY OF THE AIR QUALITY INDEX.

ACTIVE CHILDREN AND ADULTS AND ESPECIALLY PEOPLE WITH PULMONARY OR RESPIRATORY DISEASE SUCH AS ASTHMA SHOULD LIMIT PROLONGED OUTDOOR ACTIVITY.

Original Post, 4:25 p.m., Saturday, Aug. 4

Areas of northern Illinois will be under a line of severe thunderstorms moving east Saturday afternoon with heavy winds, lightning rain and possible hail.

The National Service put out a severe thunderstorm warning for Cook, Will, DuPage and Lake counties, going all the way to Chicago.

The storms are capable of 70 mph winds, heavy rains, lightning, low visibility and quarter-sized hail. Flash flooding is also expected.

People are encouraged to remain inside during the duration of the storm, and avoid driving.

According to the NWS:

THIS STORM HAS A HISTORY OF PRODUCING WIDESPREAD WIND DAMAGE ACROSS THE WESTERN AND SOUTHWESTERN CHICAGO METRO AREAS. THIS IS AN EXTREMELY DANGEROUS SITUATION. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS.

At least two power outages were seen in Tinley Park, on 171st Street near Harlem including the intersection traffic light.

The Taste of Orland Park has temporarily shut down until the storm passes.

Return to Patch for further storm updates.