In a new warning about the upcoming Atlantic hurricane season, the National Oceanic and Atmospheric Administration predicted Thursday that this year could see between 17 and 25 named tropical cyclones, the highest number it has ever forecast in May for the Atlantic Ocean.
NOAA’s forecast joins more than a dozen other recent projections from experts at universities, private companies and other government agencies that predicted a probability of 14 or more named storms this season; many claimed well over 20.
Rick Spinrad, the administrator of NOAA, told a press conference Thursday morning that agency forecasters thought eight to 13 of the named storms could become hurricanes, meaning they would include winds of at least 74 miles per hour. These could include four to seven major hurricanes – Category 3 or higher – with winds of at least 110 mph.
According to NOAA, there is an 85 percent chance of an above-normal season and 10 percent chance of a near-normal season, with a 5 percent chance of a below-normal season. An average Atlantic hurricane season has 14 named storms, including seven hurricanes and three major hurricanes.
Although it only takes one storm in a below-average season to devastate a community, conditions ripe for almost twice the average number of storms make it more likely that North America will experience a tropical storm or, even worse, a major hurricane.
There are 21 entries on this year’s official list of storm names, from Alberto to William. If this list is exhausted, the National Weather Service switches to a alternative list of namessomething he only had to do twice in his history.
NOAA typically releases a forecast for May and then an updated forecast in August. Before Thursday, NOAA’s most significant forecasts for May were for 2010, when it predicted 14 to 23 named storms; that year, 19 finally formed before the end of the season. In 2020, the May forecast called for between 13 and 19 named storms, but the updated forecast for August was even higher, with 19 to 25 named storms. This season ultimately saw 30 named storms.
The outlook for hurricanes this year has been particularly aggressive due to the unprecedented conditions expected.
As forecasters look toward the official start of the season on June 1, they are seeing a combination of circumstances that have never occurred in records dating back to the mid-1800s: record warm water temperatures in the Atlantic and the potential formation of the La Niña weather phenomenon.
Brian McNoldy, a University of Miami researcher who specializes in hurricane formation, said that without a prior example involving such conditions, forecasters trying to predict the coming season would only be able to extrapolate from previous outliers.
Experts are concerned about warm ocean temperatures.
“I think all systems are ready for a hyperactive season,” said Phil Klotzbach, an expert in seasonal hurricane forecasting at Colorado State University.
The critical zone in the Atlantic Ocean where hurricanes form is already abnormally warm just before the season begins. Benjamin Kirtman, professor of atmospheric sciences at the University of Miami, earlier described the conditions as “unprecedented”, “alarming” and an “out of bounds anomaly”.
Over the past century, these temperatures have gradually increased. But last year, with an intensity that baffled climate scientists, waters warmed even faster in a region of the Atlantic where most hurricanes form. This region, from West Africa to Central America, is warmer this year than it was before the start of last year’s hurricane season, which produced 20 named storms.
Current temperatures in the Atlantic are concerning because they mean the ocean is poised to provide additional fuel for any storms that form. Even if the surface suddenly cools, subsurface temperatures, which are also remarkably above average, are expected to quickly warm surface temperatures.
These warmer temperatures can provide energy for storms to form and help sustain them. Sometimes, if no other atmospheric conditions hinder the growth of a storm, it can intensify more quickly than usual, falling into the category of hurricane in less than a day.
Coupled with the El Niño weather phenomenon that quickly weakened in early May, the temperatures are giving experts increasing confidence that there will be an unusually high number of storms this hurricane season.
A dissipating El Niño and a likely La Niña increase confidence in the forecast.
El Niño is caused by changing ocean temperatures in the Pacific and affects weather patterns globally. When strong, it generally counteracts the development and growth of storms. Last year, warm Atlantic Ocean temperatures blunted the effect of El Niño. If El Niño weakens, as forecasters predict, there won’t be much to blunt the season this time around.
Forecasters who specialize in the ebbs and flows of El Niño, including Michelle L’Heureux of the National Weather Service’s Climate Prediction Center, are fairly confident not only that El Niño will weaken, but also that the likelihood is high (77%) that La Niña will subside. form at the height of hurricane season.
The system could throw a curveball, she said, but at this point in the spring, things are moving as forecasters predicted. A La Niña weather phenomenon would already have them expecting an above-average year. The potential for a La Niña, combined with record sea surface temperatures during hurricane season, is expected to create an environment conducive to storm formation and intensification this year.
