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

North Carolina Gov. Roy Cooper declared a state of emergency ahead of severe weather, including life-threatening flash flooding, expected across the state due to Debby.

"This weather has the potential to bring intense rain and flooding to North Carolina and we are preparing for it," Cooper said in a statement. "As the weather becomes more severe, I urge everyone to take precautions and stay safe."

The emergency declaration will allow for the state to mobilize resources to respond to the storm.

Tropical Storm Debby continues to weaken and slow down in forward speed as the center moves near the Florida-Georgia state line as of 5 p.m. ET.

Maximum sustained winds are down to 50 mph, and Debby is moving to the northeast at 6 mph. The center is currently about 30 miles southeast of Valdosta, Georgia.

As of Monday afternoon, all tropical weather and storm surge alerts have been canceled across Florida's Gulf Coast as conditions improve across much of the state.

Debby will move across southeastern Georgia through Monday evening, with the worst impacts focused there and into the Jacksonville, Florida, area. Heavy rain continues to overspread southern South Carolina as well.

-ABC News meteorologist Daniel Peck

Debby is moving inland across north Florida Monday afternoon after dumping more than 1 foot of rain in the state.

Tornadoes are possible Monday night in the coastal cities of Savannah, Georgia, and Charleston, South Carolina.

The biggest concern this week is flash flooding from the widespread, relentless rain. A flash flood emergency remains in effect in Suwannee County, Florida, northwest of Gainesville, where 10 to 15 inches of rain has fallen so far.

Debby will slowly churn into southeastern Georgia throughout Monday afternoon and evening. Through the night, the storm will be focused on Jacksonville, Florida; Savannah; and southern South Carolina.

-ABC News’ Dan Peck

More than 1,700 flights have been canceled within, into or out of the U.S. on Monday, and that number is expected to continue to climb.

American Airlines is seeing the biggest impacts because of its hubs in Miami and Charlotte, North Carolina.

American Airlines said it canceled operations at airports in Gainesville, Sarasota and Tallahassee until noon on Monday.

Sunday was one of the worst air travel days of the year with more than 2,400 cancellations.