WASHINGTON (AP) — Prepare for what almost all experts think will be one of the busiest Atlantic hurricane seasons on record, thanks to unprecedented ocean heat and a rising La Nina.
There is an 85% chance that the Atlantic hurricane season that starts in June will be above-average stormy, the National Oceanic and Atmospheric Administration announced Thursday in its annual outlook. The weather bureau forecast that between 17 and 25 named storms will form this summer and fall, with 8 to 13 reaching hurricane status (at least 75 mph sustained winds) and four to seven of them becoming major hurricanes, with at least 180 km/h wind speeds.
An average Atlantic hurricane season produces fourteen named storms, seven of which are hurricanes and three major hurricanes.
“This season is shaping up to be extraordinary in a number of ways,” said NOAA Administrator Rick Spinrad. He said this forecast is the busiest in the 25 years that NOAA has issued in May. The agency updates its forecasts every August.
About 20 other groups – universities, other governments, private weather companies – have also made seasonal forecasts. All but two expect a busier, meaner summer and fall due to hurricanes. The average of those other forecasts is about 11 hurricanes, or about 50% more than in a normal year.
“All the ingredients are certainly in place for an active season,” said Ken Graham, director of the National Weather Service. “It is of course a reason to be concerned, but not alarmed.”
What people should be most concerned about is water, because 90% of hurricane deaths occur in water and are preventable, Graham said.
When meteorologists look at how busy a hurricane season is, two factors are most important: ocean temperature in the Atlantic Ocean, where storms flare and require warm water for fuel, and whether there is La Nina or El Nino, the natural and periodic global cooling or warming. of the waters of the Pacific Ocean that are changing weather patterns worldwide. A La Nina tends to boost Atlantic storm activity, while the Pacific storm is depressing, and an El Nino does the opposite.
La Nina usually reduces the high-altitude winds that can decapitate hurricanes, and during a La Nina there is generally more instability or storminess in the atmosphere, which can cause the development of hurricanes. Storms get their energy from hot water. Ocean waters have been record warm for thirteen months in a row and a La Nina is forecast to arrive in mid-summer. The current El Nino is waning and is expected to dissipate in about a month.
“We’ve never had a La Nina in history combined with such warm ocean temperatures, so that’s a little ominous,” said Brian McNoldy, a tropical meteorology researcher at the University of Miami.
In May this year, ocean heat in the main area where hurricanes develop was as high as it was in mid-August. “That’s crazy,” said McNoldy. It’s record warm both at the ocean’s surface and at depth, which “looks a little scary.”
He said he wouldn’t be surprised if the storms hit earlier than normal this year as a result. Peak hurricane season usually runs from mid-August to mid-October, with the official season starting on June 1 and ending on November 30.
A year ago the two factors were at odds. Instead of a La Nina, there was a strong El Nino, which usually slows down the storminess a bit. Experts said at the time that they were unsure which of these factors would prevail.
Hot water won. Last year there were 20 named storms, the fourth most since 1950 and far more than the average of 14. An overall measure of the strength, duration and frequency of storms was 17% larger than normal last season.
Record warm water appears to be the key, McNoldy said.
“It really got out of hand last spring (2023) and hasn’t gotten back on track since,” McNoldy said.
“Hurricanes live on warm ocean water,” says hurricane researcher Phil Klotzbach of Colorado State University. “That’s usually fuel for the hurricane. But also when you have the warm Atlantic Ocean, that tends to push more air over the Atlantic Ocean, and more rising motion, which helps support strong thunderstorms.”
A record hot ocean is bad news across the board, not just because of hurricanes, but also hurting shipping, important ocean currents, coral reefs and fisheries, Spinrad said.
There’s the backdrop of human-induced climate change that’s making the water warmer overall, but not that much warmer, McNoldy said. He said other contributors may include an undersea volcanic eruption in the South Pacific in 2022, which sent millions of tons of water vapor into the air to trap heat, and a reduction in sulfur in marine fuels. The latter meant fewer particles in the air that reflect sunlight and cool the atmosphere a bit.
Seven of the last ten Atlantic hurricane seasons have been more active than normal in the long term.
Climate change generally makes the strongest hurricanes even more intense, causing storms to rain more and intensify quickly, McNoldy said.
Graham, former director of the National Hurricane Center, said people should be prepared for anything early because warmer oceans make storms intensify faster. All the worst Category 5 hurricanes, with winds exceeding 155 miles per hour, that have hit the United States were not even strong enough to be a hurricane three days before landfall.
Klotzbach and his team at Colorado State University – a pioneer in hurricane season forecasting – gave a 62% chance that the United States will be hit by a major hurricane with winds of at least 110 miles per hour. Normally the chance is 43%. The Caribbean has a two-in-three chance of being hit by a major hurricane and the U.S. Gulf Coast has a 42% chance of being hit by such a storm, the CSU forecast said. For the American east coast, the chance of being hit by a major hurricane is 34%.
Klotzbach said he doesn’t see how anything could change quickly enough to avoid a busy season this year.
“The die is somewhat cast,” Klotzbach said.
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