NEW: Helene becomes a hurricane, Palm Beach County under tropical storm warning

Editor's Note: This is a developing story and will be frequently updated as new information becomes available.

Florida steeled itself Wednesday for a welter of seething oceans and pelting rain as Helene deepened into a hurricane and moved unwaveringly toward the Gulf of Mexico’s heated embrace.

Palm Beach County was tossed into the fray with a tropical storm warning issued before dawn Wednesday, an alert that means damaging winds of 39-mph plus are possible within 36 hours as Helene’s yawning wind field stretches to the Gold Coast.

Broward and Miami Dade counties were issued the same warning leaving only the very farthest western span of the Panhandle free of watches and warnings.

As of 11 a.m. Wednesday, Helene had reached hurricane strength with 80 mph winds. It was about 85 miles north-northeast of Cozumel, Mexico and moving northwest at 9 mph.

Helene is forecast to grow to a major Category 3 hurricane with 120-mph winds Thursday before it is predicted to make a landfall along the Panhandle or in the Big Bend region.

For southeast Florida, including Palm Beach County, the National Weather Service in Miami says there is up to a 20% chance of sustained tropical storm-force winds of 39 mph or higher on Thursday. Areas in South Florida along the Gulf Coast including Naples have up to a 50% chance of sustained tropical storm-force winds.

Tropical meteorologists emphasized it’s not just the wind speed, it’s the breadth of Helene that is so worrisome.

Helene’s tropical storm-force winds spread 175 miles from the center early Wednesday and that is expected to expand.

The widespread winds are forecast to push up to 15 feet of storm surge into the Big Bend area, with up to 8 feet filling Tampa Bay and 3 to 5 feet pushing into the southwest coast of Lee and Collier counties. Coastal areas south of Tallahassee are expected to see up to 10 feet of surge.

"The real message we are trying to convey is that what separates this one from some of the others is that this is a really big storm, so regardless of whether it gets to a Cat 3 or falls short, we are confident that it will be really large with far-reaching impacts," said National Hurricane Center senior hurricane specialist John Cangialosi.

Cangialosi said damaging tropical-storm-force winds could extend 255 miles from Helene's center.

That’s nearly 100 miles wider than the Florida Peninsula at its widest point.

An average hurricane has tropical storm-force winds that extend about 120 miles from the center.

“Large hurricanes in the Gulf are the bane of emergency manager’s existence,” said Fox Weather hurricane specialist Bryan Norcross in a televised forecast Tuesday. “It’s the size of this storm that will surprise people.”

Jeff Masters and Bob Henson, meteorologists who write for Yale Climate Connections, said in a column this week that 2023's Hurricane Idalia had tropical storm-force winds that extended 125 miles from its center when it passed by Tampa as a deepening Category 2 storm. When Helene passes Tampa, its wind field will be about 255 miles on its east side.

In comparison, Category 5 Hurricane Michael's tropical storm-force winds reached out 175 miles form its center when it neared landfall in Mexico Beach, Florida in 2018.

Hurricane Ivan, in 2004, hit Gulf Shores, Alabama as a Category 3, but had damaging winds that spanked 290 miles from its center. Ivan's storm surge was as high as 15 feet along the coasts from Destin, Florida west to Mobile Bay in Alabama.

"Larger systems can move a lot more water," said AccuWeather lead hurricane forecaster Alex DaSilva. "If you are on the beach, 15 to 20 feet of storm surge is pretty much non survivable."

On Tuesday, Gov. Ron DeSantis expanded the state of emergency from 41 counties to 61 counties.

Rain totals through the weekend could be as high as five inches in coastal Palm Beach County with more widespread totals of 2.5 to 3 inches.

But areas in the Panhandle and Georgia, including Tallahassee and Atlanta, could see as much as 15 to 20 inches of rain, according to the Weather Prediction Center.

Kimberly Miller is a journalist for The Palm Beach Post, part of the USA Today Network of Florida. She covers real estate, weather, and the 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 warnings in effect for all of Florida's southeast coast