US: Tropical Storm Debby tracking north-northwestward across the North Atlantic Ocean off the coast of South Carolina as of late Aug. 7 /update 11

Tropical Storm Debby is tracking north-northwestward across the North Atlantic Ocean off the coast of South Carolina late Aug. 7. The storm previously made landfall as a Category 1 hurricane near Steinhatchee in the Big Bend region of the Florida Gulf Coast at around 07:00 EDT Aug. 5. As of 23:00, the system's center of circulation was approximately 40 km (25 miles) east-northeast of Charleston, South Carolina.

Forecast models indicate that the system will make landfall northeast of Charleston in South Carolina over the coming hours. The storm will weaken into a tropical depression as it tracks northward into North Carolina through late Aug. 8. The system will then likely transition into a post-tropical depression as it tracks rapidly northeastward across Virginia, far northeastern West Virginia, far northwestern Maryland, Pennsylvania, Upstate New York, northwestern Vermont in the US into Quebec Province in Canada, Maine in the US, and far northern New Brunswick Province in Canada through late Aug. 10. Some uncertainty remains in the track and intensity forecast, and significant changes could occur over the coming days.

As of late Aug. 7, officials have issued the following watches and warnings:

Tropical Storm Warning

• Edisto Beach, South Carolina to Surf City, North Carolina

Tropical Storm Watch

• North of Surf City, North Carolina to Beaufort Inlet, North Carolina

Authorities will likely issue new warnings throughout the system's progression in the coming days.

Tropical storm conditions are forecast to continue within the tropical storm warning area along the coast of South Carolina and in North Carolina and possible in the watch area in North Carolina through Aug. 8.

The system will probably generate additional rainfall totals of 7.5-23 cm (3-9 inches), with localized higher amounts, to bring storm totals of up to 64 cm (25 inches) to parts of South Carolina and 38 cm (15 inches) in southeast North Carolina through Aug. 9; considerable flooding is likely in these areas. Additional totals of 2.5-5 cm (1-2 inches) with localized higher amounts are possible across parts of southeast Georgia, bringing storm totals of up to 38 cm (15 inches) to the region, which may aggravate flooding in the area. Totals of 7.5-18 cm (3-7 inches) with localized amounts up to 25 cm (10 inches) are likely from the Piedmont of South Carolina northward across portions of Virginia through Aug. 9 and totals of 5-10 cm (2-4 inches) with localized amounts up to 15 cm (6 inches) are likely from Maryland north through Upstate New York and Vermont through early Aug. 10. This rainfall will probably result in areas of considerable flash and urban flooding, with river flooding possible. Totals of 2.5-5 cm (1-2 inches) with localized amounts up to 10 cm (4 inches) are forecast over Long Island and the remainder of New England through Aug. 10; scattered flash flooding is possible. Isolated tornadoes are possible over parts of eastern North Carolina through early Aug. 8 before shifting northward into central North Carolina and central Virginia Aug. 8.

Storm surge is possible along parts of the southeastern Atlantic coast over the coming days, with peak surges at high tide reaching 0.3-0.9 meters (1-3 feet) from South Santee River to Ocracoke Inlet including the Neuse and Pamlico Rivers. Swells from the storm will continue to affect the southeast US coast through around Aug. 11. These swells will likely cause life-threatening surf and rip current conditions.

Officials in Ocean Isle Beach, Brunswick County, issued a voluntary evacuation order asking residents and visitors to leave Aug. 7 due to the threat of the potential storm surge from Debby. Evacuation orders are also in place for dozens of residents downstream of the Cypress Lake, Simmons Mill Pond, and Oglesby Pond dams in Bulloch County, Georgia, due to the breaching of the dams. Authorities in North Carolina have issued voluntary evacuations for low-lying and flood-prone areas across the state. Authorities declared a state of emergency in Georgia and South Carolina Aug. 4, North Carolina Aug. 5, and Virginia Aug. 6 ahead of Debby's approach. Florida authorities declared a state of emergency for 61 of the state's 67 counties before the storm's arrival due to possible significant flooding. Officials issued mandatory and voluntary evacuation orders affecting thousands of people across counties in coastal areas of Florida, including mandatory evacuations in parts of Alachua, Citrus, Dixie, Franklin, Levy, Taylor, and Wakulla counties.

Authorities have confirmed one fatality in Levy County, Florida, and another fatality in Moultrie, Georgia, due to falling trees. Traffic accidents in Florida due to adverse weather conditions have resulted in one fatality in Hillsborough County and another two fatalities in Dixie County. Another person was found dead after going missing in a boat off Gulfport, Florida. Reports indicate storm surge and resultant flooding along parts of the Big Bend coast Aug. 5, with water levels around 5.5 meters (18 feet) recorded at Cedar Key. Some areas of Florida and South Carolina have received more than 30 cm (12 inches) of rain in the past few days, causing river levels to rise and triggering widespread flooding. The Sarasota Police Department in Florida had to evacuate around 500 people from flooded homes in the area. People living near the McGrady Dam in Colleton County, South Carolina, were ordered to evacuate due to the potential for the dam to fail. Reports also indicate damage to buildings, power lines, and vehicles in Moncks Corner, South Carolina. following a possible tornado.

Thousands of flights were canceled or delayed at airports across the region, including Charleston International Airport (CHS), Miami International Airport (MIA), Orlando International Airport (MCO), and Tampa International Airport, Aug. 5-7.

Sustained heavy rainfall could trigger flooding in low-lying areas and locations with easily overwhelmed drainage systems. Localized evacuations, flash flooding, and landslides are possible in hard-hit regions.

Inclement weather could trigger localized business, transport, and utility disruptions, rendering some bridges or roadways impassable. Flight disruptions at regional airports and temporary port closures are also possible. Stagnant pools of water during and after flooding may increase the incidence of insect—and waterborne diseases, such as dengue fever, cholera, and malaria. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.