'Life-threatening' Tropical Storm Debby takes aim at Florida's Gulf Coast

Tropical Storm Debby is expected to whip up rain and high surf as it churns over Gulf Coast waters on Sunday, crawling north along Florida's coast before making landfall as a "life-threatening" hurricane on Monday, forecasters said.

"It's become clearer and clearer that Debby will become a hurricane before it makes landfall," said Jamie Rhome, deputy director of the National Hurricane Center, urging people to heed evacuation orders.

Debby became a named tropical storm late on Saturday after days as a broad, sloppy system in the Atlantic, leaving Cuba's northern coast on Saturday evening, when it was about 160 km west-southwest of Key West, Florida, the NHC said.

It was crawling at 23 kph into the Gulf Coast about 390 km south-southwest of Tampa, where its winds were expected to accelerate from 72 kph up to 120 kph or more as it gains strength and becomes a hurricane by Sunday night.

"This is a life-threatening situation," the NHC said in a report. Rhome said there were "a host of hazards, not just the wind."

He warned of storm surges up to two metres along Florida's Big Bend area where it is expected to hit just southeast of the peninsular state's Panhandle.

"Now, I stand at 182 centimetres," Rhome said. "So that's over my head," he said. Heavy rains of 25 cm with spots of 38 cm of rain could be expected, more if the storm slows down or stalls over land, he said.

Debby is expected to lose some strength after landfall but bring heavy rain as it cuts across Central Florida out to the Atlantic coast. It is then expected to crawl up to Savannah, Georgia, and then toward Charleston, South Carolina, early in the week.

Ocean surges are forecast for Bonita Beach northward to Tampa Bay. Those surges could send sea waves further inland than normal, damaging structures and endangering anyone in their path.

Parts of the Gulf Coast counties Pasco Hernando and Citrus issued mandatory or voluntary evacuation orders on Saturday.

A tropical storm warning is in effect for extreme southern Florida and stretching as far north as the Fort Myers area, which was crushed by Hurricane Ian in 2022.

Governor Ron DeSantis has called up 3,000 National Guard and put most of the state's cities and counties under emergency orders ahead of the expected landfall.

Forecasters expect a large number of Atlantic hurricanes to form in the 2024 season, which began June 1, with four to seven major hurricanes forming out of 25 named storms. That is more than the record-breaking 2005 season that spawned hurricanes Katrina and Rita.

Only one hurricane, Beryl, has formed in the Atlantic so far this year. The earliest Category 5 storm on record, it ravaged the Caribbean and Mexico's Yucatan Peninsula before rolling up the Gulf Coast of Texas as a Category 1 storm, with winds up to 152 kph.

Debby is expected to follow a similar track as the deadly 2022 Hurricane Ian, which killed at least 103 people in Florida and caused billions of dollars in damage as it made its way along the Gulf Coast.