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

About 10 million people along Florida's west coast and up through Georgia and South and North Carolina were under a tropical storm alert Sunday as Debby took aim at the area and is forecast to make landfall in the Panhandle region on Monday.

Debby, now a tropical storm in the Gulf of Mexico about 190 miles southwest of Tampa, is expected to make landfall sometime between 7 and 8 a.m. in Big Bend on the Florida Panhandle as a Category 1 hurricane, state emergency officials said.

Debby is expected to create a storm surge of 4 to 7 feet in Cedar Key and Crystal River on the Florida west coast and a 2- to 5-foot storm surge farther south in Tampa and Sarasota.

The storm is forecast to move into the cities of Tallahassee and Jacksonville, bringing up to 20 inches of rain to some parts, before causing potential flooding in Georgia and the Carolinas on Tuesday, Wednesday and Thursday.

-ABC News' Kenton Gewecke

Members of the Florida National Guard have been advised to be prepared to conduct search-and-rescue missions once Tropical Storm Debby makes landfall on Monday, according to Florida Gov. Ron DeSantis.

Widespread flooding is expected for the Florida Panhandle region, particularly in the Big Bend area where Debby is expected to make landfall Monday morning as a category 1 hurricane, DeSantis said during a news conference Sunday morning.

DeSantis said the Florida National Guard and the state's Emergency Response Team are prepared to conduct search-and-rescue and provide humanitarian assistance.

"The Florida National Guard is standing by with 3,000 service members ready to assist the state Emergency Response Team, which includes search-and-rescue, route clearance, commodity distribution and protection of critical infrastructure," DeSantis said.

The governor said at least 12 swift boat crews and flat-bottom jon boat crews are also standing by to help with rescues.

He said that more than 30,000 bottles of water, more than 160,000 meals and nearly 14,000 tarps have been pre-staged in parts of Florida that are expected to be hit hard by the storm.

DeSantis said Florida utility companies have notified up to 17,000 linemen to be ready to spring into action once it is safe to repair any damage.

-ABC News Bill Hutchinson

Florida residents in the Big Bend region of the Panhandle were warned Sunday that Debby is going to bring "catastrophic rain to the area" that will cause flooding and power outages.

Kevin Guthrie, director of the Florida Division of Emergency Management, said during a news conference on Sunday that once the Debby makes landfall as a possible Category 1 hurricane on Monday morning, winds will subside quickly, but the slow-moving storm will produce an abundance of rain.

"We're going to be in a catastrophic rain situation where we have situations in Florida that will receive 15, maybe as high as 20 inches of rain," Guthrie said.

Florida Gov. Ron DeSantis told residents who are in the path of the storm to expect widespread power outages.

"It's possible that you could have serious intensification between now and landfall. It could get up to 85, 90 and 95 mph sustained winds. That is absolutely possible, particularly in parts of the state like here in Tallahassee. There's going to be a lot of trees that are going to fall down and you're going to have debris. You are going to have power interruptions," the governor said.

-ABC News' Bill Hutchinson

Florida Gov. Ron DeSantis advised residents of the state's Panhandle region on Sunday that they should be finalizing preparations for when Tropical Storm Debby makes its anticipated landfall Monday morning as a Category 1 hurricane.

"Now this is a storm that is potentially dangerous. Residents should be finalizing all of their preparations now," DeSantis said during a news conference at the state's Emergency Operation Center in Tallahassee.

DeSantis said Tropical Storm Debby was in the Gulf of Mexico about 190 miles southwest of Tampa as of Sunday morning with sustained winds of about 50 mph.

"But those are expected to increase," DeSantis said. "Tropical Storm Debby is likely to become a Category 1 hurricane before making landfall in the Big Bend region of Florida."

He said the storm was on a similar track taken by Hurricane Idalia in 2023. Idalia made landfall in Big Bend on Aug. 30, 2023, as a Category 3 hurricane and caused a devastating storm surge of 7 to 12 feet across the coastal Big Bend region in Levy, Dixie and Taylor counties.

"This storm is a similar track," DeSantis said. "It may be a tick to the west of that. It very well may have greater impacts here in the Tallahassee region than Hurricane Idalia did. Once it crosses landfall and enters the Florida Panhandle/Big Bend Region, wherever it does, it's going to move very slowly across northern Florida and southeast Georgia."

-ABC News' Bill Hutchinson