The weather service said there were multiple water rescues ongoing across southern Nashville and there were “people clinging to trees.”
“This is a life-threatening situation,” it said early Sunday morning.
Nashville Fire Department public information officer Kendra Loney said the department is fielding multiple calls of “persons trapped” inside buildings, vehicles and at homeless camps by rising flood waters. No deaths have been reported.
The weather service reported water entering a Walmart store in southern Nashville with cars in the parking lot submerged up to their windows.
Widespread rainfall totals across the middle Tennessee region since Saturday range from 4 to 8 inches, the NWS said. The Brentwood area of Nashville may have received 7 to 9 inches of rain, according to radar rainfall estimates.
More than 5 inches of rain fell between 10 p.m. local time Saturday and 5 a.m. Sunday, the NWS said.
The fast-falling rain inundated several rivers, creeks and streams, forcing them to breach their banks. Moderate-to-major river flooding was ongoing across the region Sunday morning.
The flash flooding is expected to recede as the rain ends Sunday morning, but the river flooding will take more time to clear. Several rivers will not fall below flood stage for the next 24 to 48 hours.
The next chance for rain across Tennessee and Nashville will be from Tuesday night into Wednesday, CNN meteorologist Haley Brink said.
Tornado damage reported
There were also reports of possible tornado damage in the wake of the storm system.
Late Saturday afternoon, radar showed possible twin tornadoes in middle Tennessee, about 80 miles southwest of Nashville — one near Linden and the other just east of Lexington. Two houses were “extensively damaged, one of which was destroyed” by a tornado Saturday evening in Middlefork, near Lexington, Henderson County Sheriff Brian Duke told CNN.
Several structures and homes were also damaged Saturday night when a tornado moved through Rusk County, Texas, according to David Chenault, spokesperson for the Rusk County Office of Emergency Management.
“We have had quite a bit of damage in the Mount Enterprise area of Rusk County,” Chenault said.
Most of the roads in that area were blocked by downed trees, the spokesperson said, and utilities are out.
The NWS has not officially confirmed any tornadoes in Mount Enterprise but a tornado warning was in effect around 7 p.m., when the damage happened.
CNN’s Andy Rose, Haley Brink and Tyler Mauldin contributed to this report.