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Tropical cyclones in the Atlantic could make 2020 the worst year.

When Tropical Storm Wilfred formed on September 18, the National Hurricane Center in the United States had exhausted its list of storm names for only the second time since naming began in 1950. Within hours, two more storms, now known as Alpha and Beta, formed.

The season is not over yet.

In an article on The Conversation from September 18, author Kimberly Wood, assistant professor of meteorology at Mississippi State University, explains the reasons for the high number and intensity of hurricanes this year.

“The most surprising thing is that we hit the 23rd tropical storm of the year, Beta, and that's over a month earlier than in 2005, the only other year recorded for so many named storms,” Kimberly said.

However, the 2020 Atlantic hurricane season is far from over. With the new storms, forecasters have moved from alphabetically listing people's names to letters of the Greek alphabet. And in the 2005 season, we saw 6 Greek lettering storms, ending with Zeta.

So why is the Atlantic Ocean so active this year? “Meteorologists like me have been tracking some important differences, including the many tropical storms that have formed near the American coast,” Kimberly says.

What is the reason for a large number of tropical cyclones?

When there is turbulence - a large mass of convective clouds or thunderstorms - over the Atlantic Ocean, certain weather conditions will help it develop into a tropical cyclone.

Hot water and lots of humidity help the turbulence to gain strength. The instability allows air packages to rise and continue to create thunderstorms.

This year, sea surface temperatures were above average across much of the Atlantic and wind shear was below average, meaning it was more suitable than usual for training tropical cyclones.

Maybe La Niña is linked to it as well. The La Niña phenomenon is the opposite of El Niño - it occurs when sea surface temperatures in the eastern and central Pacific Ocean are below average.

This cooling is affecting weather conditions in the United States and elsewhere, including weakening wind shear in the Atlantic Basin.

And at the beginning of September, NOAA decided that we are going into a “La Niña” climate model.

This pattern has been building for weeks, so these common conditions could have contributed to the Atlantic Ocean's adequacy for tropical cyclones this year.

A turn off the American coast.

Four hurricanes have hit the US coast this year - Hanna, Isaias, Laura, and Sally - which is more than usual at this point in the hurricane season. But we also saw several short-lived tropical storms that had less impact.

And when a tropical cyclone develops turbulence over Africa, it has a lot over the ocean with room to organize and gain strength. But this year, many storms have formed in the far north, closer to the American coast.

Most of them came from disturbances that weren't very promising until they moved over the Gulf Stream, a large ocean current that carries warm water from the Gulf of Mexico to the east coast to the North Atlantic.

Tropical cyclones are expected to form temperatures higher than sea surface temperatures exceeding 80 degrees Fahrenheit (26.6 degrees Celsius), and warm waters along the Gulf Stream can help disrupt tropical cyclones.

And since these tropical storms were already far enough north, they didn't have much time to build up.

Meteorologists have yet to investigate why so many storms form this way this season, but it's likely due to warmer-than-usual Atlantic waters and the location of the Gulf Stream.