Debby updates: Flash flooding, tornadoes target DC, Mid-Atlantic, Northeast

A city-wide curfew was lifted Wednesday morning in flood-prone Charleston, South Carolina.

No rescues were needed due to the curfew, Mayor William Cogswell said.

"After assessing overnight conditions, officials have determined that it is safe to return to normal activities," the mayor said in a statement, but he added that the ongoing storm may still lead to downed trees and power lines.

"Several roads remain closed and are barricaded," the mayor said. "Please avoid driving around barricades or entering flood waters."

Tropical Storm Debby -- currently sitting off shore of Myrtle Beach, South Carolina -- is forecast to make a second landfall late Wednesday into early Thursday near Myrtle Beach, bringing more heavy rain.

The storm is bringing significant to catastrophic flooding to portions of the Southeast, with flood watches and warnings covering much of the Carolinas. Rain totals could reach 20 to 25 inches in South Carolina and 15 inches in North Carolina.

A "high risk" for excessive flooding has been issued from North Carolina into southern Virginia for Thursday. Click here to read more.

Tropical Storm Debby’s winds slightly strengthened early Wednesday, rising to about 45 mph, as the storm moved over warm water in the Atlantic about 65 miles from the coast of Charleston, South Carolina.

Debby is expected to remain a tropical storm into Thursday, when it’s forecast to make a second landfall in South Carolina.

The National Hurricane Center said it expects the storm to not strengthen much more, maybe rising up to about 50 mph ahead of that landfall.

The storm is then forecast to continue inland overnight into Friday, with its winds slowing as it travels through North Carolina and into Virginia.

-ABC News’ Max Golembo

Tropical Storm Debby is slowly moving eastward offshore the coasts of Georgia and South Carolina.

Debby is moving east at 5 mph while max sustained winds remain at 40mph, with its center currently about 50 miles east of Savannah, Georgia, as of 11 p.m. ET.

Tornado Watch remains in effect across eastern South Carolina and North Carolina, from Myrtle Beach to Morehead City until 1 a.m. ET.

Flood Watches remain in effect from Georgia to Virginia as bands of heavy rain will continue through the night.

Debby will be back over open water tonight and could gain a bit more strength over the next 24 hours, but is forecast to remain at tropical storm intensity.

A second landfall is expected in South Carolina Wednesday evening or early Thursday morning.

ABC News' Melissa Griffin