The Number of Known Storms, Hurricanes, and Major Hurricanes Forecasted by NOAA in the Atlantic Season from 1991 to 2020

Forecasters expect 17 to 25 storms to form in the Atlantic between June 1 and the end of November. At least 8 of those are forecast to be full-blown hurricanes, as opposed to weaker tropical storms. The hurricanes are predicted to have winds powerful enough to uproots trees, destroy mobile homes and ruin other buildings.

“This season is looking to be an extraordinary one,” says Rick Spinrad, the administrator of the National Oceanic and Atmospheric Administration, which houses the National Hurricane Center.

Even relatively weak storms can cause catastrophic flooding, and the vast majority of hurricane-related deaths are from flooding, storm surge and other water hazards, warns National Weather Service director Ken Graham. In 2018, Hurricane Florence flooded the Carolinas despite being just a Category 1 storm with relatively low wind speeds. The Houston region was ravaged by Harvey in 2017: it caused massive flood damage.

People in the path of hurricanes should be prepared, and know where to evacuate and how to get there if a hurricane is bearing down on their home, forecasters and emergency managers stress.

The main factor is the high water temperatures in the tropical Atlantic. Warm water is fuel for storms, because heat provides energy for the storm’s winds and warmer water provides more moisture, leading to large, powerful and rainy storms.

Climate change is the major driver of warming oceans in the world. The vast majority of the heat on Earth that has been trapped by humans has been absorbed by the oceans.

“The warming that we’ve been seeing in the North Atlantic over the last year has made people kind of lift their eyebrows a little bit and go, ‘Huh! What’s going on there? “Seems like I’m saying something.”

“Big ones are fast,” Ken Graham, director of NOAA’s National Weather Service, said on the press call. I think this is why I’m saying they do not care about our timelines. Preparedness is absolutely everything.”

Those are big numbers — the most named storms, hurricanes, and major hurricanes NOAA has ever predicted in its May outlook. Between 1991 and 2020 there were an average of 14.4 named storms, 7.2 hurricanes, and 3.2 major hurricanes per season.

NOAA also estimates the Accumulated Cyclone Energy (ACE) for the season, a measure of overall storm activity. This year, it’s forecasting the second-highest ACE score it’s ever announced during its May outlook.