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Two and a half months before the 2024 Atlantic hurricane season officially begins, and almost six months before it enters its typical peak, forecasters are already predicting that it could be particularly active.
Although it is too early for any models to offer an official prediction—the National Oceanic and Atmospheric Administration (NOAA) won’t be issuing a forecast until May 23—experts who spoke with National Geographic warned that warm sea surface temperatures in the Atlantic and the development of a La Niña in the Pacific may create a “perfect storm” of the conditions needed for major hurricanes.
How hurricanes form
Key to the formation of any tropical cyclone—known variously as hurricanes, typhoons, and cyclones depending on their location—is the combination of warm ocean temperatures and the absence of what is known as wind shear.
Alex DaSilva, the lead hurricane forecaster with AccuWeather, explains that wind shear occurs when wind changes direction and speed at different heights in the atmosphere. That affects tropical cyclones, he says, because such storms “like their cloud structures to go straight up into the atmosphere. But when there's a lot of wind shear, when there are changing winds with direction and height, they essentially knock over those clouds so they cannot grow straight up. And so that kind of prevents typically tropical systems from really intensifying.”
They also need surface water to be at a temperature of 79 degrees Fahrenheit (26 Celsius) or higher. That warm water, and the warm air just above it, provide fuel for the storm; as warm air rushes upward, it creates a low-pressure system beneath the hurricane, into which more warm air rushes, allowing the storm to keep growing.
The intensity of an individual storm owes more, however, to the heat content of the ocean’s top 330 feet or so, explains Matt Rosencrans of NOAA’s Climate Prediction Center.
“If that water is very shallow, you'll stir that all up and maybe pull up some cold water. But if you have a large reservoir of warm water, the storm will keep pulling the water,” he says.
Record warm waters
Officially, hurricane season begins June 1 and runs through November, with storms at their most intense and numerous from August into October. One reason why some forecasters are anticipating an active season is that sea surface temperatures in the tropical Atlantic are already at record highs.
“Sea surface temperatures in what we call the main development region of the Atlantic…., off the coast of Africa to off the coast of Central America, are 1.2 degrees Celsius (2.2 F) above normal,” says Rosencrans. “That’s a record value for February.”
That means that, if those waters continue to warm at the usual rate as the year progresses, there will be plenty of fuel from which any potential storms can draw.
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