On the heels of Isaias, forecasters say 10 more hurricanes are likely this season

We ain't seen nothing yet: The ravages of Hurricanes Hanna and Isaias are just a prelude to the main act to come, top forecasters said Wednesday, with 10 more hurricanes likely to follow.

"We have increased our forecast and now call for an extremely active 2020 Atlantic hurricane season," meteorologist Phil Klotzbach said.

In all, Klotzbach and his Colorado State University forecast team predicts 24 named storms in 2020. That includes the nine named storms that have already formed: Arthur, Bertha, Cristobal, Dolly, Edouard, Fay, Gonzalo, Hanna and Isaias.

Of those, researchers expect 12 to become hurricanes (including the two that have already formed, Hanna and Isaias).

A tropical storm becomes a hurricane when its sustained winds reach 74 mph. An average season has 12 tropical storms, six of which are hurricanes.

"The team predicts that 2020 hurricane activity will be about 190% of the average season," according to the new forecast. "By comparison, 2019’s hurricane activity was about 120% of the average season."

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More bad news: Five of the hurricanes are forecast to reach major hurricane strength – Category 3, 4 or 5 – with sustained winds of 111 mph or greater. The team also said there's a 74% chance a major hurricane will hit somewhere along the U.S. coastline this year.

The reasons? Sea surface temperatures across the tropical Atlantic are much warmer than normal, and warmer water means more fuel for storms, Klotzbach said.

Also, shearing winds in the Atlantic are very weak, researchers said, which aids in hurricane development and intensification.

Another reason for the extremely active Atlantic hurricane seasonal forecast is the result of a very active West African monsoon, Klotzbach said. "More robust easterly waves and more conducive upper-level winds for hurricanes in the tropical Atlantic are typically associated with an active monsoon." Easterly waves are the small weather disturbances that eject off Africa, which can develop into hurricanes.

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Finally, as if we needed another reason, there's no sign of an El Niño, which tends to suppress Atlantic hurricane activity. In fact, conditions are very "La Niña-like" in the Pacific Ocean, Klotzbach said. La Niñas often increase hurricane numbers in the Atlantic.

Twelve hurricanes is the most the team has ever predicted in its August forecast. That's an increase from the early July seasonal forecast, which predicted 20 named storms, nine hurricanes and four major hurricanes.

The Colorado State team also noted that the forecast is intended to provide a best estimate of activity in the Atlantic during the upcoming season – not an exact measure.

And, as always, the researchers caution coastal residents to take proper precautions.

“It takes only one storm near you to make this an active season,” said Michael Bell, an associate professor in the CSU department of atmospheric science.

The National Oceanic and Atmospheric Administration will release an updated seasonal hurricane forecast on Thursday.

This article originally appeared on USA TODAY: Hurricane season 2020: Experts predict 10 more hurricanes after Isaias