Last month was the driest September in Chattanooga in more than a century, and October is starting without any immediate prospects of precipitation this week, according to the National Weather Service.
Only 0.13 inches of rain fell in Chattanooga last month, or less than 3.1% of the normal precipitation totals in September and the lowest total rainfall for any month of September since 1919. Last month was the third driest September on record in Chattanooga, and weather forecasters are predicting another dry week this week in Chattanooga.
"These really low levels of precipitation over the past month or so have definitely created some drought conditions," David Hotz, a meteorologist for the National Weather Service office in Morristown, Tennessee, said in a telephone interview. "Most of Hamilton and Marion counties and parts of Sequatchie County are under a moderate drought right now, and all of Southeast Tennessee is under abnormally dry conditions."
There is a slight chance of rain in Chattanooga by the end of the week, Hotz said, but he expects only about a tenth of an inch of rain to fall in Chattanooga on Friday or Saturday.
"We're not going to get much rain, in any event -- maybe just enough to settle the dust," Hotz said. "We will get a cold front moving into the area later this week, but there just isn't much in the way of moisture to work with."
The drought conditions this fall follow six years in Chattanooga with above-average precipitation totals, including one of the wettest years on record in 2020, according to the National Weather Service. In the first eight months of 2023 ahead of the dry September, rainfall was close to normal in Chattanooga.
Despite the dry September, lake levels remain at or above normal autumn levels across the Tennessee Valley, according to the Tennessee Valley Authority.
James Everett, manager of TVA's River Forecast Center in Knoxville, said TVA uses its network of 49 dams along the Tennessee River and its tributaries to manage lake levels and river flows, and TVA's main storage reservoirs are still 11% above normal for this time of year.
For the year, Chattanooga normally receives about 51 inches of rain, or nearly 60.9% more rain than the U.S. average rainfall of 30.2 inches.