Dispatchers at the Rutherford County Emergency Management Agency said the area was "heavily impacted" after several eyewitness reports of a tornado on the ground around 12:30 p.m.
Click here to see photos of the damage.
In Murfreesboro, 30 miles southeast of Nashville, at least three dozen homes were destroyed. Roofs were ripped away from at least a dozen homes, and some trees were blown down. A bulldozer was clearing tree limbs and other debris from streets.
Kori Bryant, in her mid-20s, and 9-week-old Olivia Bryant were identified as the dead. They apparently were trying to get in a car -- both were found outside, and the infant was in a car seat, rescue official Randy White said.
Amy Jones, 32, was at work at State Farm Insurance when she heard that her house had been leveled. She was stunned when she got to the scene and saw that the 1,800-square-foot home with a garage was lifted completely off the foundation and dropped on her neighbor's home.
"My house is on top of someone else's house. It's surreal," Jones said.
Joe Spencer, 23, a student at Middle Tennessee State University, said he had only moments to react but survived a direct hit on his house.
"I was going to open the door to see what was going on and I looked straight at a tornado," Spencer said.
He yelled at his brother to take shelter in one of the home's bathrooms and then ran to the other, jumping into the bathtub while holding his dog, LLoyd.
"The bathtub started shaking, and I just tried to grab ahold to anything I could. I grabbed the nozzle and turned on the water," Spencer said. Hours later, he was still wet up to his knees.
Spencer, his brother and dog were shaken but uninjured. Outside, the storm's power was apparent. The roof over the living room of the house was gone and the rest of the roof was caved in.
Friday afternoon, search teams fanned out across Murfreesboro, a city of about 100,500, looking for anyone trapped in homes. Clyde Atkinson, spokesman for the Murfreesboro Police Department, said he believes there were three to five touchdowns mostly in the northern and western parts of the city.
Several homes were emblazoned with a spray-painted "c," indicating emergency crews had checked them.
Gov. Phil Bredesen, Deputy Gov. John Morgan, U.S. Rep. Bart Gordon, D-Tenn., and other officials are scheduled to tour the affected areas Saturday in Rutherford County by helicopter and on the ground.
One of the homes destroyed belonged to Robert Huggins, 65, who said he, his son and two other men were working in his garage when the tornado hit. When the storm passed, his 2,500-square-foot home was gone.
"We heard it coming," Huggins said. "We went to the garage door and it got louder and louder. It was like a freight train like everybody says."
His daughter-in-law, who was inside the home, was thrown about 70 feet and was taken to the hospital. He said his 10-year-old grandson, who was also in the home, suffered only bruises.
Several possible tornadoes were reported in north Georgia as heavy rain, hail and winds downed trees and power lines. Flights were delayed for up to 90 minutes at Hartsfield-Jackson Atlanta International Airport as dark gray clouds swirled in from the west.
On Thursday night, a black funnel cloud packing winds of at least 136 mph descended on the western Arkansas hamlet of Mena, killing at least three, injuring 30 and destroying or damaging 600 homes.
Polk County, Ark., Sheriff Mike Oglesby said search-and-rescue teams had combed through the city's downtown Friday and a neighborhood just west that sustained the brunt of the storm without finding any other victims. The sheriff said he had no reports of anyone else missing in the city of 5,700 in the Ouachita Mountains.