CNN  — 

Extreme temperatures coupled with high humidity flowing from the Gulf of Mexico have set the stage for life-threatening heat in parts of the central and southern US.

Texas and Oklahoma are no strangers to excessive heat in the heart of summer and, a little over 10 days into the season, the region is bracing for stifling heat through the upcoming holiday weekend.

Temperatures are set to feel hotter in Dallas than in Death Valley, California.

Check how hot your town is forecast to be

weather heat feels like temperature 20200701

Earlier in the week, parts of Texas registered the ultimate mark of oppressive warmth. Some cities including San Antonio, Lufkin and Victoria set records for hot low temperatures, with some failing to dip below 80 degrees even in the overnight hours.

When little relief is found overnight, conditions lend themselves to dangerously hot temperatures the following day.

The seriousness of excessive heat cannot be overstated. Although hurricanes and tornadoes gain the most notoriety in the world of weather, many are surprised to learn that it is heat that is the top weather killer.

In fact, heat kills nearly twice as many Americans each year than tornadoes and almost three times more Americans than hurricanes.

weather heat warnings 20200701

Heat advisories are in effect for over 22 million Americans from Missouri to Texas, including in Oklahoma, Arkansas, and Louisiana.

“Highs will push well into the 90s and above 100s in some areas,” CNN meteorologist Dave Hennen said.

Air surging in from the Gulf of Mexico will make, Dallas reach a heat index – what it will feel like once humidity is factored in – of 110 degrees both on Wednesday and Thursday afternoon.

With these feel-like temperatures, the National Weather Service advises that heatstroke is likely within a few minutes of physical activity outdoors – or merely from prolonged exposure in the elements.

heat index chart

Fortunately, the human body has evolved to combat excessive heat beautifully. Sweating serves a key role in cooling your body temperature down to a safe level.

In fact, as you sweat, the process of evaporation cooling off of your skin can account for up to 22% of heat being released from your body, according to the National Center for Biotechnology Information.

However, this process is significantly hampered when humidity is so high that sweat fails to effectively evaporate.

That will be the case in cities such as Dallas, New Orleans , Oklahoma City and Tulsa in Oklahoma, Little Rock,