It's been a hot summer in Tennessee. And it's only getting hotter.
The strongest heat dome in the world made its way to Tennessee on Sept. 16, according to digital meteorologist Ryan Hall.
"High humidity, limited cloud cover and light winds" make the air trapped within the heat dome feel even hotter, according to NASA. The effects of a heat dome allow sunlight to reach the ground unabated and further increase temperatures.
The halfway point of the atmosphere over Tennessee is 19,665 feet. This means it is higher than the Sahara Desert, which was sitting at 19,491 feet, according to Hall. A higher heat dome causes higher temperatures. The Western Sahara will barely break 90 degrees in the next two weeks, and most days will average in the mid-80s,
according to Timeanddate.com.
The heat dome is expected to linger through the next few days, according to AccuWeather. Over the next seven days, temperatures will start decreasing.
What is a heat dome?
Heat domes occur when hot air becomes trapped near the Earth's surface due to a high-pressure buildup in the atmosphere, according to the Environmental Defense Fund.
Not too late to grab summer heat essentials on Amazon
The high pressure creates a "doming" effect and hinders hot air from rising and prevents clouds and rain from forming, keeping the hot air trapped in the dome, according to the American Meteorological Society.
The strongest heat dome on Earth right now is sitting on Tennessee.
— Ryan Hall, Y’all (@ryanhallyall) September 16, 2026
Heat makes air swell. The hotter the dome, the higher the whole atmosphere stacks up.
Over Tennessee, the halfway point of the atmosphere is 19,665 feet up. That is higher than over the Sahara. Higher than the… pic.twitter.com/3Rzh3QNvfD
A heat dome can last for days because airflow moves more slowly, or sometimes not at all.
The heat dome acts as a "lid" that compresses hot air closer to the ground, effectively keeping the hot air trapped over a large area, according to WebMD. The heat dome over Tennessee is essentially turning the entire state into a sauna.
Record high temperatures recorded across the state
Chattanooga saw 43 consecutive days of temperatures over 90. The previous record was 38 consecutive days of temperatures over 90 in 1993, according to the National Weather Service office in Morristown.
On Sept. 16, Nashville reached 99, a record high for the day. Middle Tennessee is expected to see triple-digit temperatures this weekend.
The heat just won't retreat! Triple digit heat indices are expected into the weekend, so be sure to stay hydrated and cool!
— NWS Nashville (@NWSNashville) September 16, 2026
Highs should come down a bit into next work week so hang in there! 🫠🥵 #TNwx #MiddleTNwx pic.twitter.com/LfGyN3duMt
In Memphis, hazardous heat is expected to continue through the weekend. On Sept. 17 and Sept. 18, West Tennessee will reach 99 degrees, producing heat indexes of 105.
A heat advisory has been issued for most of the state, according to the NWS. The advisory says hot and humid temperatures will cause heat indexes above 100.
Knoxville 7-day forecast
Sept. 17: Sunny and hot, with a high near 95. Heat index value as high as 103.
Sept. 18: Sunny and hot, with a high near 95. Heat index value as high as 103.
Sept. 19: Sunny and hot, with a high near 94.
Sept. 20: Mostly sunny and hot, with a high near 93.
Sept. 21: Mostly sunny and hot, with a high near 93.
Sept. 22: Partly sunny and hot, with a high near 90.
Sept. 23: Partly sunny, with a high near 87.
Afton Pratt covers trending and breaking news for Knox News and Tennessee. She can be reached at ampratt@usatodayco.com.
This article originally appeared on Knoxville News Sentinel: Tennessee feels hotter than the Sahara Desert. Here's why
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