Update 3:27 p.m.

The AP is now reporting that more Michigan homes and businesses --around 400,000-- lost power this week:

DTE Energy Co. says about 210,000 of its customers were without power Thursday after a new round of damaging thunderstorms made its way across the state, knocking down trees and power lines. Since Tuesday, DTE says about 300,000 of its customers have been affected. CMS Energy Corp. unit Consumers Energy says about 97,000 of its customers lost power, including about 36,500 in the Flint area. That number was down to 80,000 Thursday afternoon.

2:21 p.m.

More than 300,000 homes and businesses are powerless in Michigan today after a wave of storms knocked down trees and power lines this week, the Associated Press reports.

Two storms hit the Detroit-area last night and this morning in a week that has seen four consecutive days of severe thunderstorms across the state.

Along with the thunderstorms, Excessive Heat Warnings continue today for 34 of Michigan's southernmost counties, and the National Weather Service predicts all-time record highs in some Michigan cities.

You can find a list of cooling centers open today in the Detroit-area, mid, and west Michigan by following these links. Call ahead, though, because some are experiencing electrical problems in wake of the storms.

The Red Cross of Southeast Michigan offers some tips on how to stay safe in this extreme heat wave:

Prepare. Discuss heat safety precautions with members of your household. Have a plan for what to do if the power goes out.

Discuss heat safety precautions with members of your household. Have a plan for what to do if the power goes out. Dress for the heat . Wear loose-fitting, lightweight, light-colored clothing. Avoid dark colors because they absorb the sun’s rays. It is also a good idea to wear hats or to use an umbrella.

. Wear loose-fitting, lightweight, light-colored clothing. Avoid dark colors because they absorb the sun’s rays. It is also a good idea to wear hats or to use an umbrella. Stay hydrated. Carry water or juice with you and drink continuously even if you do not feel thirsty. Avoid drinks with alcohol or caffeine, which dehydrate the body.

Carry water or juice with you and drink continuously even if you do not feel thirsty. Avoid drinks with alcohol or caffeine, which dehydrate the body. Eat small meals and eat more often . Avoid high-protein foods, which increase metabolic heat.

. Avoid high-protein foods, which increase metabolic heat. Slow down and avoid strenuous activity. If you must do strenuous activity, do it during the coolest part of the day, which is usually in the morning between 4 and 7 a.m. Take frequent breaks.

If you must do strenuous activity, do it during the coolest part of the day, which is usually in the morning between 4 and 7 a.m. Take frequent breaks. Stay indoors when possible . If air-conditioning is not available, stay on the lowest floor out of the sunshine. Remember that electric fans do not cool, they simply circulate the air.

. If air-conditioning is not available, stay on the lowest floor out of the sunshine. Remember that electric fans do not cool, they simply circulate the air. Be a good neighbor . During heat waves, check in on family, friends and neighbors who are elderly or ill and those who do not have air conditioning. Check on your animals frequently, too, to make sure they are not suffering from the heat.

. During heat waves, check in on family, friends and neighbors who are elderly or ill and those who do not have air conditioning. Check on your animals frequently, too, to make sure they are not suffering from the heat. Learn Red Cross first aid and CPR/AED

The National Weather Service predicts that the heat will break over the weekend, but tomorrow could be hotter than today with temperatures breaking the 100-degree mark.

-Elaine Ezekiel, Michigan Radio Newsroom