The TVA building and Market Street are seen from the Republic Centre building in Chattanooga.

The summertime heat baking Chattanooga at the start of autumn this year set another record Wednesday when temperatures reached 100 degrees Fahrenheit — the highest October temperature ever in Chattanooga.

The National Weather Service said Chattanooga reached the century mark on the thermostat for only the fourth time this year and the first time ever after the fall equinox. Andrew Moulton, a meteorologist for the National Weather Service in Morristown, Tennessee, said Chattanoogans should expect temperatures to reach nearly as high again Thursday before the heatwave begins to moderate Friday.

"The ridge of high pressure over the entire Southeast doesn't seem to want to move so we've seen record-breaking temperatures across the whole region for much of the past week," Moulton said. "While the hot weather is here, the cold air seems to all be in the Northwest [where up to 4 feet of snow fell in parts of Montana]. Mother Nature seems to want to balance out things."

The heatwave in the Tennessee Valley is also setting power demand records for October following the highest average peak load in September for the Tennessee Valley Authority as air conditioners are running more to try to cool homes and offices across TVA's 7-state region. TVA reached the second highest October power peak on record on Tuesday and was expecting a comparable or perhaps even higher peak by Thursday.

"This is an extremely high demand for this time of year so we're having to work extra hard to make sure we keep the lights on," TVA spokeswoman Malinda Hunter said. "We have begun to internally try to conserve power ourselves under what we call an internal power supply alert."

Chattanooga's hottest days of 2019

* 100 degrees on Aug. 13

* 103 degrees on Sept. 13

* 100 degrees on Sept. 17

* 100 degrees on Oct. 2

Source: National Weather Service

TVA implemented steps to limit its own energy use, including keeping its offices and plants at warmer temperatures.

While TVA workers may be sweating a bit more, Hunter said TVA isn't asking yet that any of its customers conserve or limit their power use and so far TVA has been able to fully meet all of its demand.

TVA's power peak Tuesday of 28,551 megawatts was the second highest for October in the 86-year history of TVA. But the peak was still well below the all-time peak of 33,482 megawatts TVA reached in August 2007 when temperatures across the Tennessee Valley averaged 102 degrees.

TVA is having to meet this week's power peaks with two of its seven nuclear reactors shut down for refueling and maintenance outages and another coasting down toward a maintenance outage next week. TVA spokesman Jim Hopson said Browns Ferry Unit 2 and Watts Bar Unit 1 are offline and Sequoyah Unit 1 is operating at 75% power as it prepares for an upcoming outage.

"This time of year is typically when we start to bring down our units for maintenance outages because it's typically much cooler," Hunter said. "Fortunately, our diverse portfolio and power purchase agreements help us meet high demands, even with some of our units offline."

TVA is still getting extra power from its 29 hydroelectric dams on the Tennessee River system, but such generation has been limited after below average rainfall during both August and September.

"We just wrapped up the second driest September on record with barely more than a half inch of rain Valley-wide for the month," Hunter said. "Normal average rainfall for September is over 3.5 inches. Despite the dry conditions, we still have water stored in tributaries and we continue to meet flow requirements for water quality and supply."

Hunter said consumers can find advice on how to limit their energy consumption and trim what will likely be higher electric bills this month for most homeowners by visiting the website

Contact Dave Flessner at or at 757-6340.