Helene is expected to hit Florida this week

(This story has been updated to add new information.)

A storm brewing in the Caribbean is forecast to strengthen into a hurricane in the Gulf of Mexico over the next few days and make landfall on the Gulf Coast as early as Thursday – possibly as a severe Category 3 system.

“Everyone along the Florida Panhandle and Big Bend region needs to be prepared for the impacts of a hurricane,” Alex DaSilva, AccuWeather's senior hurricane expert, said Monday, adding that the constellation has the potential to be the strongest hurricane to make landfall in the U.S. so far this season.

WeatherTiger meteorologist Ryan Truchelut summed it up in an online post Monday afternoon: “Helene will be coming your way faster than you think, so switch to hurricane mode now. While there remains uncertainty about the forecast track and intensity, Florida is not going to get out of this crisis.”

Florida Governor Ron DeSantis declared a state of emergency for 41 counties along and near Florida's Gulf Coast on Monday because of the threat from the storm. The declaration said there is a significant risk of storm surge and flooding, especially in areas still recovering from the elevated water levels left behind by Hurricane Debby.

Most forecast models predict the hurricane will make landfall in Florida or the northern Gulf Coast on Thursday, said Weather.com meteorologist Jonathan Erdman.

The system was upgraded to potential tropical cyclone nine status on Monday morning and will be named Helene once it develops into a tropical storm, which is expected to happen sometime Monday or Tuesday.

Tropical storm warnings and hurricane warnings were also issued for parts of western Cuba and Mexico's Yucatan Peninsula on Monday.

Meteorologists warn: Gulf Coast residents should prepare now

Unlike many hurricanes that move across the Atlantic for days or weeks and give people plenty of warning before they make landfall, this hurricane is forecast to develop and intensify rapidly once it reaches the Gulf of Mexico.

“Now is the time to prepare for a hurricane making landfall on the Gulf Coast. Don't wait until this storm is officially named,” said AccuWeather meteorologist Jon Porter.

He said there is a possibility that this storm could further develop into a major hurricane, classified as a Category 3 on the Saffir-Simpson Hurricane Wind Scale, with maximum sustained winds of 111 to 129 mph (178 to 207 km/h).

This could be the storm that will remember the 2024 hurricane season, Porter said.

Follow the storm: A tropical storm could form in the Gulf of Mexico early this week

Where is the system now?

A weather forecast released by the National Hurricane Center on Monday morning called for showers and thunderstorms associated with an extensive low-pressure system over the northwestern Caribbean to gradually become better organized.

“The environmental conditions appear to be favorable for the further development of this system,” the center said.

“A tropical depression or storm is likely to form over the next day or two as the system moves northward across the northwestern Caribbean and into the southeastern Gulf of Mexico, where further development is expected.”

The Hurricane Hunters will study the approaching storm on Monday, the center reported.

The storm could quickly develop into a massive hurricane

Meteorologists at the Hurricane Center warn that the system could rapidly strengthen over the Gulf of Mexico and possibly reach speeds of 177 km/h.

The “environmental and marine conditions appear favorable for significant strengthening,” the hurricane center said in its 11 a.m. discussion. A model shows a 95 percent chance that the storm's wind speed will increase by 75 mph or more over the next 72 hours, the center said.

Helene could develop into a powerful hurricane in the Gulf, Erdman said. There is enough deep, warm water in the northwestern Caribbean and parts of the Gulf of Mexico to give the storm strength.

In fact, Erdman reported that the heat content of the Gulf of Mexico had reached a record high for this time of year, according to tropical scientist Brian McNoldy of the University of Miami.

What effects can we expect from Helene?

Wind: Sustained wind speeds of at least 178 km/h are possible. Where the storm makes landfall on Thursday, strong wind gusts of up to 193 km/h are expected.

Rain: Widespread rainfall of 8 to 12 inches (20 to 30 centimeters) is expected, possibly causing flooding. Showers will begin as early as late Tuesday afternoon or early evening, starting over the Keys and moving northward, according to the Florida Public Radio Emergency Network.

Power outages: Regional and localized power outages are expected throughout the Florida Panhandle and Big Bend region, as well as much of Georgia, Alabama, southern Tennessee, and parts of far western South Carolina and North Carolina, according to AccuWeather.

Storm surge And Tornadoes also pose a major threat as the storm approaches later this week.

High surf: The hurricane center warned in a marine weather forecast that seas in the southeastern Gulf were expected to reach 15 feet by Wednesday morning and peak at 25 to 30 feet Thursday morning.

Fourth hurricane to make landfall this year?

If the storm makes landfall on the US mainland as a hurricane, it would be the fourth hurricane to make landfall on the US mainland this year, along with Beryl, Debby and Francine.

In three other years since 2000, there have been four hurricanes that made landfall: 2004, 2005 and 2020, said Phil Klotzbach, senior scientist at Colorado State University.

Storm Tracker

Spaghetti models for Caribbean system

https://data.tallahassee.com/storm/nine/al092024/#spaghettiEmbed:

Experts had predicted an “extraordinary season”

At the beginning of the year, federal meteorologists predicted an “extraordinary” season: up to 24 named storms were possible.

In a typical season, there are 14 named storms, based on weather records from 1991 to 2020.

Hurricane John threatens Mexico

In the Pacific, the hurricane center reported that Hurricane John is getting stronger as it approaches the coast of southern Mexico. The system is expected to approach the southern coast of Mexico in the next day or two and move inland on Tuesday or Wednesday.

The center said that “damaging hurricane-force winds, a dangerous storm surge and life-threatening flash floods are expected in parts of southern Mexico.”

Contributors: Dinah Voyles Pulver, USA TODAY; Cheryl McCloud, USA TODAY Network

This article originally appeared on USA TODAY: Hurricane forecast: Landfall on Gulf Coast this week