The National Oceanic and Atmospheric Administration predicts that this Atlantic hurricane season will be more active than usual, according to a statement released on Thursday.
While NOAA does not expect this hurricane season to reach the historic levels of 2020, which saw a record-breaking 30 named storms, forecasters predict between 13 and 20 named storms with up to five major hurricanes. Hurricane season begins on June 1 and peaks in the fall, so NOAA will update its forecast in August, says NOAA seasonal hurricane forecaster Matthew Rosencrans to NPR’s Laurel Wamsley.
The announcement comes a month after NOAA raised the definition of an “average” Atlantic hurricane season from 12 named storms to 14 named storms.
There is a 60 percent chance that 2021 will see an above-average hurricane season, which would be the sixth above-average hurricane season in a row, reports CNN’s Allison Chinchar. In April, Colorado State University meteorologists released their prediction of an above-average hurricane season as well.
"The primary reasons why we're going above average is the low likelihood of a significant El Niño event and the relative warmth in the tropical (Atlantic) but especially the subtropical eastern Atlantic," says Phil Klotzbach, a hurricane expert at Colorado State University, to CNN.
El Niño events reduce hurricanes because they bring increased vertical wind shear, which means that wind speed and direction changes more dramatically at different heights in the atmosphere. Without that effect paring down the number of storms, it is possible that the Atlantic could see between six and ten hurricanes, with windspeeds over 74 miles per hour, and between three to five major storms with winds over 111 miles per hour.
“Now is the time to ensure that you have an evacuation plan in place, disaster supplies on hand, and a plan to secure your home quickly,” said acting NOAA Administrator Benjamin Friedman during a press briefing on Thursday, per the Verge’s Justine Calma. “It was a mere six months ago that the most active Atlantic season on record ended, and here we are now on the cusp of a new hurricane season.”
The last Atlantic hurricane season was particularly active because of a La Niña weather event, which has ended. Although 2021 may mark the sixth above-average hurricane season in the Atlantic, the way that storms have become more common has not been directly connected with climate change.
“Climate change has not been linked to the frequency of storms but is has been linked to the intensity of storms,” says Matthew Rosencrans, head of forecasting for the U.S. National Weather Service, to Reuters’ Erwin Seba. Hurricanes’ strength and the level of destruction, like that caused by slow-moving storms Hurricane Havey and Hurricane Sally, has been linked to climate change.
Rosencrans tells NPR, “Most of the increase in storms is really a reflection of the better technology to detect the storms.”
More sensitive equipment has improved meteorologists’ ability to spot storms in the middle of the Atlantic and measure their windspeed. For instance, NOAA uses aircraft called hurricane hunters to measure air pressure, humidity, temperature and wind speed and direction in storms.
As of Friday, the National Hurricane Center already had its eye on what may be the first named Atlantic storm of 2021, that is developing northeast of Bermuda, per the Weather Channel. The first named storm of 2021 will be called Ana, and the second will be named Bill.