Much of Michigan under excessive heat warnings, advisories ...

We have several hot days coming. As a result, heat advisories and excessive heat warnings are in effect. Here’s what counties are in the more extreme heat warning and why.

Most of the Lower Peninsula is under a heat advisory while a few counties in the southeast corner are an excessive heat warning. See the map below.

A heat advisory is a little less dangerous than an excessive heat warning.

A heat advisory in Michigan is issued if the heat index is going to be between 100 and 104 degrees. An excessive heat warning is normally used for days when the heat index will climb above 105 degrees.

It’s pretty tough to get above 105 degrees on the heat index in Michigan. This is why an excessive heat warning is fairly rare in Michigan. The most recent excessive heat warning was issued for the highly populated counties of southeast Michigan on June 15-16, 2022.

The heat advisory covers the southern half of Lower Michigan and doesn’t just run for today. The heat advisory is in effect until 8 p.m. this coming Friday. This is due to each day having the chance to warm into the 90s with the heat index around 100 degrees each afternoon.

Below shows how the highly populated areas with a lot of pavement and buildings can affect our weather. The National Weather Service at Detroit has issued the more dangerous excessive heat warning for Genesee, Oakland, Macomb and Wayne counties. They forecast heat indices to mostly stay just below the 105 degree threshold. However, they believe the extended time period on the verge of the heat warning warrants the official issuance of the warning.

Note that all of the pavement in these urbanized counties will hold heat and make the hot stretch more stressful on a body.

If you work outside, you will want to plan your jobs accordingly if you can. Work out of the sun as much as possible.

Remember the effects of sun and heat are cumulative. You might not feel the morning heat is too bad, but it stresses your body to not be able to handle the afternoon heat.

I’ve had heat exhaustion before and on the verge of heat stroke. If you don’t pay attention to your body the heat illnesses can sneak up on you. Once you feel sick it’s too late to avoid it. Then you may have a few days before your body will let you get out into the heat again. It’s almost like you can become allergic to the sun and heat. As soon as you get out into the heat after heat exhaustion you may not be able to handle routine heat as you did before.

Don’t worry. This is Michigan. We can already see a big break in the heat wave coming. I’m writing about that next and will publish it here.