Heat Index A Factor This Afternoon

The Heat Index will be near dangerous levels again today: High temperatures will be in the mid 90s, but it will feel like it’s about 105° this afternoon, and that has led to some heat advisories across the area.

Heat Advisories in effect from Madison and Marshall counties west.

This is where we expect the heat index to hit or exceed 105° for several hours this afternoon.

Higher humidity = higher Heat Index: Pretty much anyone who has suffered through a few hot Tennessee Valley summers can tell you “It’s not the heat that get’s you, it’s the humidity”.  And most people know that the higher the humidity, the higher the Heat Index is.

Higher humidity leads to a higher Heat Index.

But, why exactly does more humid air feel hotter to you and me? Well, to answer that question, we have to look at how our bodies naturally try to cool us down when we get hot.


The more humid the air, the slower our sweat evaporates.

When our bodies get hot, we sweat. While it can be a little bit gross, sweating can cool us off. Sweat comes to the surface of our skin, and then evaporates away. Evaporation is a cooling process, meaning as the water in our sweat evaporates, it cools our skin down. But, when the air is very humid, the process of evaporation slows down, meaning our body’s natural way to keep us cool doesn’t work as well, and that’s where things can get dangerous.

Heat exhaustion and heat stroke: When our body’s natural ways to keep us cool fail, either because sweat isn’t evaporating or we run out of sweat, then heat exhaustion or heat stroke can occur. These conditions are both dangerous, and heat stroke can kill, so it’s important to know the symptoms of both.

Heat Stroke and Heat Exhaustion are dangerous. Both require immediate action.

If you think you are suffering from either heat exhaustion or heat stroke, seek help immediately.

Staying cool in the August heat: Most of the tips to avoid heat exhaustion or stroke are pretty straightforward, but it’s always a good idea to keep these in mind when the weather gets hot.

Following these simple steps can prevent heat related illness

Be sure to stay safe out there today, and stay aware of how your body is reacting to the heat. The good news is it appears that some lower temperatures and higher rain chances are on the way for the Tennessee Valley. We’ve got the details on that at the WHNT News 19 Forecast Discussion. 

– Meteorologist Alex Puckett

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