Although only mid-June, the temperature at McGhee-Tyson Airport crept up to 96 degrees with a heat index of 103 on Wednesday. The previous day saw a high of 94 with a heat index of 106, according to the National Weather Service. Highs temperatures on Thursday were projected to reach 97 with heat index values as high as 107. At 3 p.m. Thursday, temperatures at the airport had reached 97 degrees with a heat index of at least 100 degrees with the true heat of the day soon to come.
The good news — at least for the short term — is that a cold front is expected to blow into the area tomorrow, bringing with it the possibility of storms and a brief break from the heat. Then we ramp up well into the 90s next week.
“That’s what’s at stake”
Such temperatures aren’t at all unprecedented, according to meteorologist Anthony Cavallucci of the NWS station in Morristown.
“The weather across much of the eastern U.S. has been experiencing dangerous heat with heat index values exceeding 105 degrees. Heat is the number one weather-related killer,” Cavallucci explained Wednesday.
“The heat has been caused by a ridge of high pressure aloft acting as a ‘block’ for storm systems to move into our area. The combination of high pressure, mostly sunny conditions, higher humidity due to southerly winds, and lack of cool air making its way into our area is causing the dangerous heat. Thankfully, the daytime temperatures will ‘cool’ over the weekend. Unfortunately, we will experience more hot temperatures next week as the ridge builds again over the same areas as this week,” he said.
While climate scientists acknowledge the prolonged heat waves pummeling the Indian subcontinent this month — where high temperatures have ranged from 108 to 120 in recent weeks — local officials say it’s not so easy to conclude the weather in the Eastern U.S. is directly attributable to global trends.
“I am not familiar with any research connecting this heat wave with climate change,” said Cavallucci. “Past records going back to 1871 for Knoxville show June temperatures exceeding 92 degrees 18 times in 1952, 1943, and 1936. In 2011, there were 8 days that exceeded 92 degrees. Heat index values are not recorded in our climate data records.
“In other words, there have been other Junes in Knoxville that have been hotter than the current heat we’re experiencing. Although, we aren’t finished with the month of June! So far, we’ve only exceeded 92 degrees twice this month.”
Chris Carnevale, climate advocacy director at the Southern Alliance for Clean Energy, said that while the blazing temperatures pummeling Knoxville might not be directly traced at this point to human-driven climate change, the overall picture is becoming clear.
“Experts have documented increasing heat waves because of a warming climate caused by burning fossil fuels, and they project the warming will continue,” he said.
Knoxville generally averages a single day each year with a heat index of 105 or above, he said, citing a 2019 study from the Union of Concerned Scientists. By the late 21st century, however, the area could see as many as 56 days per year with 105 index values if major changes in energy policy aren’t implemented. Even if they are put in place, the number of days with a 105 heat index will likely grow to 13 days annually.
“That’s what’s at stake here,” Carnevale said.
The report can be found at the UCS website.
TVA says it’s ready
Jim Hopson, spokesman for the Tennessee Valley Authority (TVA) said the utility was prepared for the current heat wave.
“Obviously, Mother Nature is fully in charge of the weather, but TVA and local power companies plan for periods of high demand, even ones that occur a bit earlier than normal,” Hopson said.
“We start by continually investing in upgrading our existing generation and transmission resources, as well as creating new ones. Our teams perform extensive preventative maintenance on our generating assets during lower power demand periods — typically in the spring and fall — so we can have confidence that they will perform as designed when we need them the most,” he said.
“Those efforts make us confident in the reliability and resiliency of our public power system, which has been 99.999% reliable for 21 consecutive years — among the best performance in the nation.
This Monday, June 13, we successfully supplied a peak load of 31,311 megawatts — the highest load ever seen in the month of June in our service area,” he said.
“Of course, we know that individuals may be concerned about the impact of the heat and high power demand on their future power bills. We encourage them to join TVA and local power companies (we pay power bills, too) by taking a few simple steps to help reduce their power use, especially during the peak demand period from 2 p.m. until 6 p.m.”
Hopson suggested setting thermostats up just one degree and using fans to circulate air, closing windows on the sun-facing side of buildings, and avoiding the use of appliances like ovens, dishwashers and clothes dryers until the sun goes down and temperatures drop.