A wave of storms started hitting the South and East Thursday afternoon, with softball-sized hail in Georgia and high winds downing trees in upstate New York.
Thunderstorms accompanied by heavy rains and strong winds in Atlanta late Thursday caused three deaths from falling trees, and left more than 100,000 without power, according to local media reports.
The known toll of dead from Sunday's massive tornado in Joplin, Missouri, meanwhile went up by one on Thursday to 126.
A series of twisters had killed another 16 people in three states on Tuesday night.
By Thursday, nearly 100 hours after the deadliest tornado in the United States in 64 years, officials in Joplin were still trying to find 232 people unaccounted for after the tornado, which also injured more than 900 people.
Search crews with cadaver dogs were still looking for victims in the miles of rubble left by the storm, but hope was fading for finding people alive.
One of those who had been unaccounted for was confirmed dead on Thursday. Skyular Logsdon, a 16-month-old boy ripped from his mother's arms during the tornado, was identified by a great aunt who knew him well, the boy's father told Reuters.
The fate of the boy touched the hearts of thousands as his relatives searched hospitals and morgues after finding his clothes wrapped around a telephone pole and his teddy bear nearby.
The storms in the nation's midsection overnight resulted in at least 81 reports of tornadoes and severe weather across at least 11 states, according to a National Weather Service severe weather map.
"It was a very active day," said David Imy, meteorologist with the National Storm Prediction Center.
Thursday afternoon, locally damaging thunderstorms were seen from the central Gulf Coast to northern New England, according to AccuWeather.com.
Softball-sized hail fell on Morganton, Ga., damaging vehicles, while winds downed trees and power lines in Pennsylvania and New York, the website said.
There were reports of a possible tornado in Crawford County, Pennsylvania, according to AccuWeather. Many areas of the Appalachians will be hit or threatened by the storms Friday evening. Later tonight through Friday, the main threat will be flash, urban and small-stream flooding.
The death toll from the tornadoes that hit Oklahoma Tuesday climbed to 10 with the discovery of the body of Ryan Hamil, 3, on the shoreline of a lake west of Oklahoma City, Captain Chris West of the Oklahoma Highway Patrol said on Thursday. His 16-month-old brother Cole had also been killed.
The spate of tornadoes this week has overshadowed severe flooding along the Mississippi River.
Flooding also is a problem in North and South Dakota where residents of Bismarck and Pierre were warned of flooding from the Missouri River.
Severe thunderstorms are possible Friday across most of the country from southeast Montana in the West to the Florida Panhandle in the south and then northeast to northern Vermont, according to weather.com.
The tornadoes overnight ranged from Bedford, Indiana to Smithville, Tennessee and south to Farmersville, Louisiana.
In Smithville, a city about 70 miles southeast of Nashville. a market and a gas station were blown away, and a restaurant was severely damaged, according to Mayor Taft Hendrixson.
"It could have been a whole lot worse if it had stayed on the ground longer," Hendrixson said.
Tornadoes have killed a total of 504 people in the United States so far this year, making it the deadliest tornado year since 1953, according to the National Weather Service.