The rain is focused on the Carolinas through Thursday and then will move north.
Tropical Storm Debby is slamming the Southeast with heavy rain after making landfall in Florida as a Category 1 hurricane on Monday.
At least six people have been killed in Florida and Georgia.
The highest rain total so far is south of Tampa, Florida, where about 19 inches of rain fell.
In Georgia, more than 11 inches of rain struck northwest of Savannah, and in South Carolina, 14 inches of rain was recorded between Charleston and Hilton Head Island.
On Tuesday afternoon, Debby is located about 10 miles southeast of Savannah and is crawling north at a very slow speed.
The heavy rain will stretch from Charleston to Wilmington, North Carolina, on Tuesday. Storm surge could reach 4 feet from Savannah to Cape Fear, North Carolina, and tornadoes are possible.
Flash flood warnings are in effect for Savannah, Charleston and Myrtle Beach, South Carolina. Rainfall rates could reach 1 to 2 inches per hour during the heaviest downpours, which will bring more flooding.
The worst of the rain is expected along the South Carolina-North Carolina border through Thursday evening. A rare "high risk" for flash flooding was issued from Charleston to Raleigh, North Carolina, where rain totals could climb to 25 inches through Thursday.
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A curfew in Charleston, South Carolina, has been extended to 7 a.m. Wednesday as the flood-prone city braces for potentially life-threatening flooding.
"Residents are advised to stay off the roads unless there is an urgent emergency," the Charleston Fire Department said.
Charleston is under a flash flood warning. Up to 1 foot of rain has already fallen in the city, with more to come.
Despite weakening since moving over land, Debby is still maintaining its tropical storm status, producing maximum sustained wind speeds of 45 mph.
As of 11 p.m. ET, over 150,000 customers in Florida and Georgia are still without power, according to PowerOutage.us.
With Debby's center about 35 miles west of Brunswick, Georgia, much of the heavy rain and showers have since moved out of Florida (except for the extreme northeastern corner of the state closer to the Georgia border). However, with the storm slowing down even more, Debby will stay stuck over the Southeast for the better part of this week, meandering over Georgia and the Carolinas.
Even though the storm is expected to weaken a bit more overnight, Debby is still expected to bring historic rainfall and life-threatening flooding to portions of southeastern Georgia and the coastal areas of the Carolinas over the next few days. Rainfall totals from this event are expected to reach between 10 and 20 inches.
Already, portions of southeastern Georgia and South Carolina have seen between 3 to 6 inches of rainfall, but with rainfall rates of 1.5 to 3 inches per hour possible, flood alerts remain in effect.
A Flash Flood Warning was issued for Charleston, South Carolina, where rainfall rates between 1.5 and 2.5 inches are expected. Ongoing or new flooding is expected, with an additional 2 to 4 inches of rain possible over the next few hours.
As onshore flow continues, storm surge remains an issue in Savannah, Georgia, and Charleston, South Carolina. Storm surge alerts remain in effect up the Georgia and Carolina coastlines.
Rainfall aside, Debby could also generate some spin-up tornadoes as it swirls over the Georgia-South Carolina border tonight. As a result, a Tornado Watch also remains in effect for parts of southeastern Georgia and South Carolina until 1 a.m. ET.
Over the next 48 hours, Debby is expected to meander back over the Atlantic but will continue to hug the coastline before heading back inland over the Carolinas again. Slight strengthening can't entirely be ruled out as it moves back over water, but ultimately, Debby is expected to weaken once it moves back inland. Strength aside, it will still bring significant rainfall to portions of the Southeast, which will likely lead to catastrophic flooding in some areas.
Debby is expected to eventually drift toward the north/northeast by the end of the week into the weekend. As it heads north, it will likely weaken to a tropical depression or remnant low. Regardless, heavy rainfall is still expected up the I-95 corridor heading into this weekend.
-ABC News meteorologist Shawnie Caslin Martucci
As of Monday evening, 146,034 customers are without power in Florida, according to the latest update from a U.S. power outage map.
This marks an improvement from Monday morning, which saw nearly 300,000 customers without power at 9:50 a.m. ET, the height of outages across the state.
During a press conference in Tallahassee Monday morning, Gov. Ron DeSantis said the state's emergency department had 17,000 linemen working to restore power in the wake of the storm.
"We have a lot of restoration personnel ready to go," DeSantis said.
Tropical Storm Debby continues to weaken, with maximum sustained winds down to 45 mph as of 8 p.m. ET. The weather pattern is moving very slowly to the northeast at 6 mph, and the center is currently about 50 miles east of Valdosta, Georgia.
Even though Debby is now inland and continues to weaken, many of the impacts -- especially the heavy rainfall and dangerous flash flood threat -- will not abate for several days. For many locations in coastal Georgia and South Carolina, the worst is yet to come.
The tornado threat continues along portions of the Georgia and South Carolina coasts this evening and into tonight. A Tornado Watch remains in effect from Savannah, Georgia, to Charleston, South Carolina, until at least 1 a.m. ET.
Parts of Florida, including Sarasota and Lakewood Ranch, are reporting over a foot of rain from Debby, and portions of Suwannee County, including Live Oak, are getting around a foot as well.
So far, parts of Georgia, including Savannah, are reporting nearly 4" of rain. The same can be said for Hilton Head, South Carolina.
Conditions will continue to deteriorate across much of South Carolina overnight Monday into Tuesday, with widespread areas of heavy rain and the potential for dangerous, significant flash flooding during nighttime hours.
Coastal flooding and storm surges will continue to increase in the coming hours as winds increase and more persistent heavy rain moves in, heading into high tide along the Georgia and South Carolina coasts.
By late Tuesday afternoon or early evening, the center of Debby will likely be moving off the Southeast coast and into the Atlantic, where it will meander for about 24 hours before likely turning back toward the coast and potentially making another landfall as a tropical storm somewhere along the South Carolina coast by Thursday morning or afternoon.
-ABC News meteorologist Daniel Peck
