Story at a glance
- The Atlantic Hurricane Season broke records, recorded 30 named storms and 12 which made landfall in the continental U.S.
- Meteorologists say warm sea temperatures is the culprit.
The overly active 2020 Atlantic Hurricane Season ended on Monday, Nov. 30, with only one incident brewing north of the Madeira Islands in the eastern Atlantic, with only a 40 to 60 percent probability of forming into a cyclone in the next two days.
2020 boasted a record-breaking 30 named storms and 12 storms that made landfall in the continental U.S., the National Oceanic and Atmospheric Administration (NOAA) wrote.
The average year sees only 12 named storms, resulting in a 150 percent increase in the 2020 season.
Among these storms, 13 of the 30 named storms developed into hurricanes, with wind speeds of 74 miles per hour or more. Six of those had top winds clocked at 111 miles per hour or more.
The previous record-setting hurricane season was in 2005, with 28 recorded storms.
“The 2020 Atlantic hurricane season ramped up quickly and broke records across the board,” Neil Jacobs, the acting NOAA administrator, said. “Our investments in research, forecast models, and computer technology allowed forecasters at the National Weather Service, and its National Hurricane Center, to issue forecasts with increasing accuracy, resulting in the advanced lead time needed to ensure that decision makers and communities were ready and responsive.”
This is now the fifth consecutive year with above-normal Atlantic hurricane activity, which is currently attributed to the warm phase of the Atlantic Multi-Decadal Oscillation (AMO). The AMO is a series of lengthy changes in sea surface temperatures in the North Atlantic Ocean, and last for decades.
The AMO is a naturally occurring phenomenon, with experts noting it has been occurring for the last 1,000 years.
Since the mid-1990s, the AMO has been in a warmer phase, meaning storms maturing into hurricanes on the Atlantic have been more frequent.
“As we correctly predicted, an interrelated set of atmospheric and oceanic conditions linked to the warm AMO were again present this year. These included warmer-than-average Atlantic sea surface temperatures and a stronger west African monsoon, along with much weaker vertical wind shear and wind patterns coming off of Africa that were more favorable for storm development. These conditions, combined with La Nina, helped make this record-breaking, extremely active hurricane season possible,” said Gerry Bell, the lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center.
And climate change may be playing a role. Climate scientist Michael Mann of Penn State University told USA Today, "The main ingredient in our forecast was the unusual warmth of the tropical Atlantic Ocean, and the warmth of the oceans cannot be explained without taking into account the warming effect of increasing carbon dioxide concentrations in the atmosphere from fossil fuel burning.
"A warmer ocean surface appears to favor more storms, but as importantly, it means more energy to intensify tropical storms into major hurricanes, including Category 5 monsters like Iota."