The heat is on in the central portions of the country

Summer heat has been blasting the central portions of the country. Temperatures in the 90s to near 100 degrees have been reported from Texas to Wisconsin as excessive heat warnings were issued across much of the central U.S. Heat index values, or “feels-like” temperatures were over 100 degrees, making conditions potentially dangerous.

Late last week, Denver tied a record with a temperature of a scorching 105 degrees. In Manhattan, Kan., the mercury hit a very hot 106 degrees. The heat dome was expected to expand into the Northeast over the weekend. More record heat is expected across the central U.S. this week as the huge high pressure dome expands.

The feels-like temperatures are also known as a “heat index” which was developed by R.I. Steadman of the National Weather Service back in 1979. The heat index is calculated by combining air temperature and relative humidity levels. For example, a 90-degree temperature combined with a 90-percent relative humidity level would push the heat index up to a very dangerous 122 degrees Fahrenheit.

One of the most deadly heatwaves in our nation’s history occurred in Chicago between July 13-15, 1995. In the southwestern part of that city on July 14, 1995, the heat index soared to near 130 degrees Fahrenheit, killing more than 500 people. The day’s high was a record 109 degrees with a relative humidity level of 80 percent.

The region of the country with the highest levels of heat and humidity are east of the Rockies, especially in the southern portions of the country. Depending on the age and health of individuals, prolonged exposure to heat index temperatures over 100 degrees can lead to sunstroke, heat exhaustion, muscle cramps and even heart attacks. Since the 1930s, it’s estimated that close to 30,000 Americans have died during big heatwaves, mainly in the Desert Southwest and regions east of the Rockies, particularly the Deep South and the Southeast.

The western portions of the country rarely experience the hot temperatures and high humidity levels. Thanks to the Rocky Mountains, the humid air from the Gulf of Mexico is blocked from entering the Far West. Although we may receive some triple-digit readings, the relative humidity levels are generally less than 20 percent, hence only a slight rise in the overall heat index.

During the summer season, the Inland Northwest will have days with temperatures in the 90s. Although, the heat and humidity levels are much lower in our part of the country when compared to areas east of the Rockies, one could get heat stroke in very hot weather.

For example, symptoms of heat stroke are when the body temperatures reach 103 degrees or higher. The skin is hot, red, dry or damp and there is a fast, strong pulse. Headaches, dizziness, nausea, confusion and passing out are classic signs of heat stroke. If someone is experiencing heat stroke, call 9-1-1 right away as it’s considered to be a medical emergency. The person should also be moved to a cooler place and try to lower their body temperature with cool cloths or a cool bath. One of the most important things is to not give the person anything to drink.

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In terms of our local weather, temperatures will be very pleasant through the middle of the week with highs mostly in the 70s across Coeur d’Alene and surrounding regions. The Fourth of July looks good with the nice temperatures, but there could be a few showers in the mountain areas.

Summerlike weather should move back into the Inland Northwest toward the end of the week as temperatures will be warming well into the 80s. It’s quite possible we’ll see readings hit the 90-degree mark sometime next week for the first time of the 2018 season. The northwestern portion of the country has been seeing relatively mild to warm temperatures as the big heat has been east of our region. But, as the big high pressure ridge expands, our temperatures will be warmer.

We’re in a pattern of below-normal precipitation as June ended up a little below the 1.93 normal as Cliff measured 1.61 inches of rain last month. For July, the normal rainfall is .92 inches.

The rest of the summer season should see warmer temperatures with only scattered afternoon and evening showers and thunderstorms, but mainly over the mountains. The upcoming fall of 2018 still looks like we’ll turn toward the wetter side.

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Contact Randy Mann at randy@longrangeweather.com.