When potential tropical cyclone 9 officially became Tropical Storm Helene late on Tuesday morning, forecasters who had been watching the storm’s recent development from a swirl of thunderstorms in the western Caribbean Sea were able to begin piecing together more information about how big Helene might grow — and where it might go next.
Helene’s center was identified late on Tuesday morning, and that can have a significant influence on the forecast track of the storm. It gives forecasters and computer models a more accurate place to start from. And so the puzzle pieces began to fit together enough for forecasters to have some confidence in saying that Helene will likely turn into a major hurricane before making landfall along Florida’s Big Bend.
The storm’s center can wobble and move before it strengthens into a hurricane, said John Cangialosi, a senior hurricane specialist with the National Weather Service, on Tuesday. The track guidance from weather models is very tightly clustered, which typically means forecasters would have strong confidence in where the storm will go. Until now, it has not been easy to locate a center, and those models might be off slightly. So forecasters warned in an update on Tuesday to prepare for the possibility that the entire guidance could shift east or west.
Some models show the storm growing weaker and tracking west, and others much stronger and east. At the same time, most show something in between and point at the Big Bend. All of these solutions are on the table, and a high-altitude hurricane hunter flight took off from Florida early on Tuesday afternoon to investigate the steering currents and hopefully provide data that will help the later computer models.
The storm is also forecast to become a major hurricane, meaning that it could be a Category 3 or higher, with wind speeds of at least 111 miles per hour. This, too, could change, with some outliers showing a more vigorous storm and some showing a weaker hurricane or even a tropical storm.
One thing forecasters are growing confident of, Mr. Cangialosi said, is that this storm will be a vastly large hurricane, possibly similar in size to Irma and Katrina, which caused widespread damage. That means the storm surge, wind and rainfall effects will extend well away from the center, particularly on the east side.
A storm this size could potentially put large populations, like those living in the Tampa Bay area, at risk for damaging winds and surge that they didn’t experience during Idalia, a 2023 storm with a similar track and intensity as what is forecast for Helene. Idalia was much smaller. It also means that damaging winds may reach farther inland to cities like Tallahassee.
Like Francine a couple of weeks ago, Helene faces a deadline. If it doesn’t become a hurricane by Wednesday morning, it might not have enough time to reach Category 3 strength before making landfall.
On Tuesday morning, Gov. Ron DeSantis of Florida warned people about the uncertainty of the forecast models. “It’s important that people don’t get wedded to these cones,” he said. You could be out of the cone, he added, “and still have major impacts.” Speaking from the state’s emergency operations center in Tallahassee, Mr. DeSantis said the fact that the National Hurricane Center forecast a major hurricane — Category 3 or higher — before the storm even formed indicated that it could quickly intensify in the deep, warm Gulf waters.
There’s still a lot of uncertainty here,” he said, urging Floridians to make storm preparations now. “People should just know that this is out there.”
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