Hotter Weather Building across Tennessee

NASHVILLE, Tenn. - Weather forecasters are warning of heat indexes of 110 degrees or higher as high pressure builds over Tennessee.

The index is the "feels like" combination of heat and humidity.

National Weather Service forecaster Trevor Bouchet in Nashville described it as the obverse of the wind chill factor in wintertime -- an apparent temperature reading.

"It's a coupling of high temperature and relative humidity, essentially a combination of what it feels like," Bouchet said.

A heat advisory is in effect from 11 a.m. Wednesday until 11 a.m. Thursday for the western half of Tennessee. An excessive heat watch runs from Thursday morning through Saturday evening for the same sector. Special weather statements, cautioning of high temperatures and humidity, have been posted through Thursday for the Cumberland Plateau and East Tennessee.

Moisture trapped below the high pressure ridge could produce scattered thunderstorms statewide.

"They will be short-lived, sub-severe type storms about any afternoon," Bouchet said.

While forecasters and health authorities say the usual hot weather cautions apply, some people still have to be outside working in the heat.

Summer is an ideal time to roof a building, said Brian Pierce, owner of Southern Pride Roofing in Knoxville, because the heat helps seal the shingles.

Pierce says his crews start at 6 a.m. when neighborhood rules permit, but they try to be off the roof between 3 p.m. and 5 p.m. -- usually the hottest part of the day. They use that time to take an extended lunch and haul away old roofing materials.

There are also a couple of lessons learned over time.

"We wear long-sleeved shirts," Pierce said. "They absorb the sweat and it (the evaporation) cools you down. Those long sleeves really help."

Pierce said his crews also eat a lot of fruit in the summertime, particularly watermelon and cantaloupe, because it contains a lot of water.

There should be no problems powering all of the air conditioners humming statewide.

Tennessee Valley Authority spokesman Scott Brooks in Knoxville said all six nuclear power units are online and all of TVA's generation capacity is available.

Summer demand for power is a little higher than the winter load, but Brooks said the current hot weather spell hasn't pushed the system close to record demand.

The all-time peak demand, reached during hot weather, is 33,400 megawatts.

"With temperatures in the mid-90s and upper 90s over the next couple of days, we expect a demand of between 30,000 and 31,000 megawatts," Brooks said.

There's a slight improvement in the forecast for the weekend.

"By Friday, we have a little bit of a cool front and it should cool us by a few degrees," Bouchet said.

"It's not much," he cautioned. "In fact, if you stepped outside, you probably wouldn't notice it."