Tropical Storm Debby forms; expected to hit Big Bend as Cat 1 hurricane

A slow-blooming tempest that stalked Florida this week became Tropical Storm Debby on Saturday afternoon and is expected to hit North Florida's Big Bend area as a Category 1 hurricane, weather forecasters said Saturday afternoon.

A hurricane warning is now in effect for the state's Gulf Coast from the Suwannee to the Ochlockonee rivers, and a tropical storm warning is in effect for the coast west of the Ochlockonee River to Indian Pass, and the coast east of the Suwannee River to Yankeetown, the National Hurricane Center said in its 5 p.m. update.

Debby's winds were up to 40 mph, and tropical-storm force winds extended out 140 miles from its center of circulation, the Hurricane Center said.

Upgraded to Tropical Depression Four late Friday, and to Debby at 5 p.m. Friday, the swirl of firing thunderstorms was forecast to make landfall in the Big Bend region of the state early Monday as a Category 1 hurricane.

AccuWeather lead hurricane forecaster Alex DaSilva said Friday that if the system leans toward the left, or the western edge of the forecast track cone, it would have more time to fuel up on the incredibly warm waters of the Gulf.

“It might be strengthening all the way up until it makes landfall, DaSilva said. “If it rides the western portion of the cone, there is nothing to slow the strengthening other than it hitting land.”

A tropical storm warning went into effect at 2 p.m. for the Florida Keys from the Seven Mile Bridge westward and north of the Seven Mile Bridge to the Channel 5 Bridge. The storm warning includes the Dry Tortugas and the west coast of the Florida peninsula from south of Yankeetown to East Cape Sable.

As of 5 p.m., the storm was 100 miles southwest of Key West and starting to move into the southeastern Gulf of Mexico. It's forecasted to move north over the eastern Gulf of Mexico through Saturday and into Sunday, reaching the Florida Gulf coast late Sunday or Monday.

The hurricane forecast cone of uncertainty has shifted some since Friday, with the landfall area stretching anywhere from Indian Pass southeast of Panama City to Yankeetown. Inland areas including Tallahassee, Gainesville, Jacksonville and Daytona Beach were also in the cone as the system passes through the state and into Georgia as a tropical storm. It is forecast to reach the Atlantic Ocean late Tuesday into early Wednesday.

Much of the Gulf Coast and parts of coastal southeast Florida can expect rain totals of 6 to 10 inches this weekend through Thursday morning. This could cause local flash and urban flooding, including isolated river flooding. Isolated areas near Tampa could get as much as a foot of rain.

Hurricane Center forecasters have been cautious to note the uncertainty of Gulf Coast-skimming storms.

"Since the forecast track is almost parallel to the west coast of the Florida Peninsula and the southeast coast of the U.S., only a small change in the track could lead to large changes in which land areas receive any landfalls and the biggest impacts," NHC forecasters wrote in a Friday discussion.

Storm surge is also a concern along the shallow Gulf Coast with up to 5 feet possible along the immediate coast from Bonita Beach to Indian Pass. A 1- to 3-foot storm surge is possible along the very southern tip of the peninsula from Card Sound Bridge to Bonita Beach.

More: Your hurricane prep manual for 2024

Florida Gov. Ron DeSantis declared a state of emergency Thursday for 54 counties. Seven more counties were added late Friday, putting 61 of Florida's 67 counties under a state of emergency.

Tropical storm-force winds could reach the southwest coast of the state during the day Sunday, with areas in the Big Bend region beginning to feel the brunt of the system's winds late Sunday. National Weather Service meteorologists in Tampa said residents should be prepared Sunday for gusty winds of 30 to 50 mph, some coastal flooding and isolated tornadoes.

Robert Molleda, meteorologist in charge at the National Weather Service office in Miami, emphasized that impacts could be felt far afield of the cone.

“(Saturday) is not going to be a good day. It’s going to rain a good part of the day,” Molleda said. “The other main concern is the potential for flooding.”

Forecasters have maintained 2024 will be a busy hurricane season, despite the mostly quiet month of July. The combination of an emerging La Niña climate pattern and exceptionally warm water temperatures led NOAA to issue its highest storm forecast on record in late May with a prediction of 17 to 25 named storms, including eight to 13 hurricanes.

Colorado State University increased its number of named storms for the season to 25 from the 23 it forecast June 1. It increased the number of hurricanes to 12 from its original forecast of 11.

An average hurricane season has 14 named storms and seven hurricanes.

While there were concerns earlier in the week that the storm would stall or meander in a collapse of steering winds, the thought Friday was it would get picked up by a trough moving over the Ohio Valley that would take it across the state and into the Atlantic.

After brutal storm landfalls in 2022 by Category 4 Ian and 2023 by Category 3 Idalia, people on the Gulf Coast may be fearing a major hurricane or the potential for rapid intensification. Rapid intensification is when a storm gains 35 mph or more in a 24-hour period.

That seems unlikely, said Jeff Masters, co-founder of Weather Underground and a meteorologist for Yale Climate Connections. Not only is the system getting a slow start after raking across the mountainous spine of Cuba, it’s not expected to be over water long enough to rapidly intensify.

If the storm was expected to linger over water, there would be more concern.

"The eastern Gulf of Mexico is one of the last places we want to see a developing storm system in the coming days," said Michael Lowry, a meteorologist with South Florida ABC affiliate Channel 10, in a daily briefing. "Water temperatures are not only the warmest on record for the time of year in this area but are some of the warmest waters anywhere on the planet right now."

Kimberly Miller is a journalist for The Palm Beach Post, part of the USA Today Network of Florida. She covers real estate and how growth affects South Florida's environment. Subscribe to The Dirt for a weekly real estate roundup. If you have news tips, please send them to kmiller@pbpost.com. Help support our local journalism; subscribe today.

This article originally appeared on Palm Beach Post: Tropical Storm Debby forms, expected to be hurricane in Big Bend