Stalled off the Florida coast, Tropical Storm Debby was dumping unrelenting rain on the state Monday, causing flooding amid high winds and a continuing threat of tornadoes.

The storm has already killed at least one person after apparent tornadoes struck central Florida on Sunday, officials said.

And with Debby coming to a standstill in the northern Gulf of Mexico, the winds and rain may continue for days.

As of Monday morning, Debby was centered about 90 miles south-southwest of Apalachicola in the Florida Panhandle, the National Hurricane Center said.

The storm had maximum sustained winds of 50 mph, and tropical-storm-force winds — those 39 mph or stronger — extended 200 miles out from its center.

“Little movement is expected during the next couple of days, but this forecast remains uncertain,” forecasters said.

“Tropical storm conditions will continue over portions of the Florida Gulf Coast today.”

Debby is expected to dump a total of 10 to 15 inches of rain over the eastern Florida panhandle and northern Florida, with isolated amounts of up to 25 inches, the hurricane center said.

Total rain accumulations of 5 to 10 inches are expected over central Florida and southeast Georgia into coastal South Carolina, with isolated maximum amounts of 15 inches possible, forecasters said.

“Given the recent heavy rainfall and wet soil conditions, these additional amounts will exacerbate the flash flood threat across portions of northern Florida and southern Alabama,” the weather agency said.

A tropical storm warning remained in effect for an area east of the Alabama-Florida border to Suwannee River in Florida. A tropical storm watch was in effect from south of the Suwannee River to Englewood, Florida.

Seminole, Florida, received more than 10 inches of rain on Sunday, according to preliminary 24-hour totals from the National Weather Service. Pinellas Park, Florida, received nearly 9 inches, and the Ocala, Florida, airport measured nearly 8 inches.

Other preliminary rainfall totals included 6.58 inches in Orange Springs, Florida; 6.27 inches in St. Petersburg; and 6.03 inches in Apalachicola, Florida, according to the weather service.

A few tornadoes were possible Monday across the eastern Florida Panhandle, along with western and central Florida. A large swath of the state was under a tornado watch until Monday afternoon. Numerous flood watches and warnings were also posted.

On Sunday, two apparent twisters destroyed four homes in Florida’s Highland County, said Gloria Rybinski, emergency operations spokeswoman for the county.

A woman was found dead in a home in Venus, located in the middle of the state between Port St. Lucie and Sarasota, Rybinski said.

Damage was also reported in St. Petersburg Beach from a suspected tornado that witnesses said came ashore as a waterspout from the Intracoastal Waterway Sunday night, CNN affiliate WFLA reported.

Roofs were torn from buildings, trees were downed and vending machines were tossed through the air, according to the station. Witnesses said chairs and debris flew past their windows.

“It was so windy and rainy, I couldn’t go outside to look,” resident Michael Hamm told the station. “Ten or 15 minutes later, when I did, I noticed the roof was gone over the deck, the picnic tables had blown off, the railing was gone, the electricity was off. … We didn’t get hurt so we’re very lucky.”

The Sunshine Skyway bridge, which stretches over Tampa Bay and connects Bradenton with St. Petersburg, Florida, was closed Sunday because of high winds and remained closed Monday, CNN affiliate Bay News 9 reported.

Winds in the area have been clocked at between 20 to 30 mph with higher gusts, the station said. Seas were between 12 and 15 feet.

In Madeira Beach, which lies on the Gulf of Mexico about 10 miles west of St. Petersburg, Debbie Ponceti said her front lawn had been reduced to mush and the water in a lagoon near her house was steadily rising.

“Typically when a thunderstorm happens, it is over in 20 minutes,” Ponceti said Sunday. “But this has been going on all day.”

In nearby Redington Beach, Keri Ann Eversole said winds appeared to be blowing between 40 to 50 mph.

“The rain was coming down sideways,” Eversole said. It “felt like glass.”

Video from the Tampa area showed drivers inching through water on a flooded street Sunday night, with at least one stranded. The floodwater was beginning to recede Monday morning, but several stalled cars remained on flooded roadways, CNN affiliate WTSP reported.

The area received 8 to 10 inches of rain over the weekend, WFLA said. More rain was forecast for the Tampa area through Wednesday.

A forecast track showed Debby remaining a tropical storm as it eventually creeps northward and makes landfall, possibly early Friday, on the Florida Panhandle. But forecasters warned Debby’s track remained uncertain.

“Guidance continues to be all over the place, with some models taking Debby west and north of its current position and others moving east or northeast and ultimately into the Atlantic,” the National Hurricane Center said.

The storm also posed a flooding threat. Forecasters warned the combination of a storm surge and the tide would cause coastal areas to be inundated with water.

An area from Apalachee Bay to Waccasassa Bay, Florida, could see a 4-to-6 foot surge, while areas on either side — the west coast of Florida south of Waccasassa Bay and the Alabama-Florida border east to Apalachee Bay — could see 2 to 4 feet. An area stretching from southeastern Louisiana to the Alabama-Florida border could get a 1-to-3-foot surge, according to the hurricane center.

The storm has raised concerns for those working on 596 manned oil and gas production platforms throughout the Gulf, run by various companies.

Shell said Sunday that it had evacuated 360 staff the previous day and was planning further evacuations. ExxonMobil said it has “evacuated nonessential personnel” from its offshore facilities and is preparing to evacuate the rest.

And BP spokesman Brett Clanton said Sunday evening that the company has evacuated the “majority of our offshore personnel in the Gulf of Mexico” due to Debby. “Those unable to be evacuated will shelter in place for the storm,” he said.

Debbie’s uncertain track has some in Louisiana worried. Gov. Bobby Jindal declared a pre-emptive state of emergency on Sunday.

In Plaquemines Parish, Louisiana’s southernmost parish, authorities used baskets and tubes to keep Highway 23, the parish’s main evacuation and emergency route, free of water should the 4-foot levees be topped, said Billy Nungesser, parish president. The levees were being sandbagged as an additional precaution.

— CNN’s Sarah Dillingham contributed to this report.