Extreme, life-threatening and potentially historic flooding is expected from Debby across the Southeast U.S.

AccuWeather Global Weather Center – August 4, 2024

AccuWeather expert meteorologists say Debby could rapidly intensify into a hurricane later today in the Gulf of Mexico before it makes landfall in Florida tomorrow and produce potentially catastrophic flooding across the Southeast.  

“The flooding threat from Debby could lead to a life-threatening and catastrophic flooding disaster in communities across the Southeast if this storm slows down or stalls out,” said AccuWeather Chief Meteorologist Jon Porter. “The combination of hours of relentless, heavy rain and a persistent onshore flow could prevent rivers and waterways from draining into the Atlantic, making the flooding impacts even worse. Do not be lulled into any false sense of security that Debby is presently rated as a tropical storm on the Saffir-Simpson Hurricane Wind Scale. There are many cases, such as Florence in 2018, where a Category 1 hurricane or tropical storm caused catastrophic flooding.” 

Debby is now rated a 3 on the AccuWeather RealImpact™ Scale for Hurricanes for the United States, which warns of widespread and substantial flooding, structural damage to buildings and mobile homes, as well as downed trees, power outages and major coastal inundation.   
 

In contrast to the Saffir-Simpson Hurricane Wind Scale, which classifies storms by wind speed only, the AccuWeather RealImpact™ Scale is based on a broad range of important factors. In order to better communicate a more comprehensive representation of the potential impact of a storm on lives and livelihoods, the scale covers not only wind speed, but also flooding rain, storm surge and economic damage and loss. Some of these hazards such as inland flooding and storm surge in many storms result in more deaths and economic loss than wind.  

Porter says Debby eventually might need to be rated a 4 or higher on the AccuWeather RealImpact™ Scale for Hurricanes if the storm rapidly intensifies in the Gulf of Mexico or if Debby slows or stalls along the southeast Atlantic coast along the Carolinas.   
 

A 4 on the AccuWeather RealImpact™ Scale for Hurricanes warns of widespread catastrophic flooding that may last days to weeks, widespread power outages, structural damage to many buildings, especially near the coast, as well as severe coastal inundation. 

AccuWeather hurricane experts are forecasting Debby to make landfall in the Big Bend region of Florida as a hurricane on Monday, pushing up to 10-15 feet of deadly storm surge into the area.  

“This area is very prone to storm surge, especially in the bays and inlets along the Florida Gulf Coast,” warned AccuWeather Lead Hurricane Expert Alex DaSilva. “The shape of the coastline is like a bowl in the Big Bend area. Debby is expected to push a lot of water into this area as it makes landfall. We’re concerned about a potentially deadly storm surge of 10 to 15 feet of water, especially if this storm approaches the coast near high tide.” 

AccuWeather Senior Director of Forecasting Operations Dan DePodwin said Debby is forecast to make landfall as a Category 1 hurricane with maximum sustained winds of 74-95 miles per hour on the Saffir-Simpson Hurricane Wind Scale. 

“We are concerned that Debby could rapidly intensify over the next 24 hours before making landfall in Florida. There’s plenty of very warm water and low wind shear,” said DePodwin. “It’s not out of the realm of possibility that Debby could strengthen into a Category 2 hurricane on the Saffir-Simpson Hurricane Wind Scale if it takes advantage of the environment conducive to strengthening. We’ve seen several hurricanes rapidly intensify in very warm waters in this part of the Gulf in recent years.” 

AccuWeather hurricane experts are forecasting a zone of 8-12 inches of rainfall and wind gusts of 80-100 mph in the area where Debby makes landfall in Florida and moves inland, with an AccuWeather Local StormMax™ for wind is 120 mph.  

“Debby has been slowly strengthening throughout Sunday morning. The only factor holding this storm back has been some dry air on the western side of the storm track,” explained DaSilva. “Most of the thunderstorms have been to the east of the center of circulation. Once storms start to wrap around the center of circulation, Debby could start developing and intensifying very quickly.” 

DaSilva also urged people to be prepared for the risk of embedded tornadoes in rainbands across much of Florida today, as well as the safety threats at beaches from rough surf and dangerous rip currents.  

Major travel impacts are expected throughout the southeast U.S. and beyond. AccuWeather expert meteorologists are predicting 750 flight cancellations on Monday and 900 flight cancellations on Tuesday.  

Prepare for hurricane impacts in Florida 

Rounds of rain and gusty thunderstorms will spread northward over the Florida Peninsula on Saturday and expand throughout the weekend. AccuWeather expert meteorologists warn that this tropical threat could spin up tornadoes over land and waterspouts over water.  

AccuWeather Chief Meteorologist Jon Porter says families across Florida should be prepared for the threat of nocturnal tornadoes, which pose a greater threat since they are obscured by darkness and many people are sleeping. 

“Have your shelter or safe place ready for tornado warnings.  You want to be able to move there quickly, especially with an overnight threat. You want to be in the lowest part of your home, ideally an interior room away from external walls, windows and doors,” said Porter. “Most people are sleeping at night. Tornadoes that happen at night are two times more likely to be fatal than tornadoes that occur during the day; that’s why it’s such a concern.” 

AccuWeather expert meteorologists are forecasting 4-8 inches of rainfall across the Florida peninsula and 8 -12 inches of rainfall in northeast Florida. More than a foot of rain is possible.  

Wind gusts of 60-80 mph are possible late Sunday into Monday as this tropical threat approaches the Big Bend region of Florida. The AccuWeather Local StormMax™ for wind gusts is 100 mph.   

AccuWeather expert meteorologists warn that 3 -6 feet of storm surge are possible along the Gulf Coast of Florida from the Big Bend region, through Tampa Bay, and as far south as Fort Myers Beach. Storm surge of 1-3 feet is possible in far southwestern Florida and the Florida Keys, as well as the Atlantic coast of Florida from Miami through Jacksonville.  

Rough surf and dangerous rip currents are expected, which could create hazardous beach conditions before the tropical threat and downpours reach the coastline.  

Major flooding impacts expected in Georgia and the Carolinas 

After Debby blasts the Gulf Coast of Florida, the storm is expected to move across northern Florida and southeastern Georgia, before it moves over the warm waters of the Atlantic Ocean and slows to a crawl.  

“As soon as Debby moves off the Carolina coast, we’re expecting this storm to stall and produce rainfall rates on the order of 1 to 3 inches of rain per hour, which can create dangerous and potentially catastrophic flooding,” warned DaSilva. “We are concerned about a potentially historic flooding event in the Carolinas and across the Southeast.” 

AccuWeather hurricane experts are forecasting a zone that could receive 18-24 inches of rainfall across eastern Georgia, South Carolina and North Carolina. The AccuWeather Local StormMax™ for rainfall is 32 inches. 

“We are very concerned about a life-threatening and potentially historic flooding event with staggering rainfall totals that could be measured in feet, not inches,” warned DePodwin. “Do not let your guard down, even though Debby is expected to be a tropical storm off the southeast coast. The rainfall totals and flooding potential are expected to be extreme and life-threatening.” 

AccuWeather Forecast Graphics

Additional AccuWeather Resources:

Debby to impact Georgia, Carolinas with life-threatening flooding and storm surge this week

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