The number of Atlantic storms this year has been exceptional.

So exceptional that the World Meteorological Organization is about to run out of names for these churning cyclones. During each Atlantic storm season, there are 21 names to choose from, running alphabetically from A. (Q, U, X, Y, and Z aren't included because the names must be readily recognizable by a wide range of people.) The 21-name list has only been exhausted once, in 2005, the year of Hurricane Katrina and the most tropical storms on record.

This year, only "Wilfred" is left, which would be storm number 21. Once the World Meteorological Organization exhausts those 21 names, it uses Greek letters, beginning with "Alpha."

"The number of storms is extraordinary," Falko Judt, a research meteorologist at the National Center for Atmospheric Research, told Mashable on Monday.

A storm earns a name (or letter) when it meets the criteria for a "tropical storm," meaning an organized, spinning storm system with sustained winds of at least 39 mph. Once these winds hit 74 mph, a tropical storm becomes a hurricane.

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2020 has a good shot at breaking the record for named (and lettered) storms. On Monday (Sept. 14, 2020), Tropical Storm Vicky formed in the Atlantic, becoming the 20th storm of the season. But in 2005, the 20th storm didn't arrive until Oct. 5.

Atmospheric scientists accurately predicted, as far back as April, that 2020 would be a busy or even "hyperactive" season, largely due to well-above-average sea surface temperatures and a lower likelihood of hurricane-shredding winds. The first half of the season, however, saw mostly short-lived or weak storms, rather than pummeling hurricanes. (Though, it only takes one major storm, like Hurricane Laura, to upend lives and communities.) "At the moment it's been quantity over quality," explained Judt.

Importantly, a storm doesn't need to have 150 mph winds to wreak havoc. Category 1 Hurricane Sally, a "low-grade" hurricane with some 85 mph winds, is expected to bring "historic life-threatening flash flooding" to the Gulf Coast on Tuesday and beyond.

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It's almost certain 2020 will run through a good number of Greek letters. There's currently an excellent set-up for storm formation in the Atlantic. Hurricanes feed off of warm waters, and ocean surface temperatures are above-average across much of the Atlantic basin. What's more, the "seeds" of tropical storms — clusters of thunderstorms rolling off of Africa — are quite active. Once they hit the warm Atlantic, the storms can pick up steam.

"It's almost like a train," Brian Tang, an atmospheric scientist at the University of Albany, told Mashable on Monday. "Once they move off the African coast, the natural thing they want to do is continue to develop."

SEE ALSO:Why it's impossible to forecast the weather too far into the future

As the oceans continue to absorb profound amounts of human-created heat from the atmosphere in the coming years, hurricane scientists expect this heating to impact hurricanes. They don't, however, expect more storms overall. Rather, they expect big storms to grow more intense, as more water naturally evaporates into the air, giving storms energy and moisture to intensify. This means more damaging and dangerous extreme weather events.

"We think there will be an uptick in the most intense storms," Tang told Mashable in July, as the busy 2020 season started kicking into gear.