For the second time in two years, and only the third time in history, meteorologists have exhausted the list of names used to identify storms during the Atlantic hurricane season.
With the formation of Subtropical Storm Wanda on Saturday, there have been 21 named storms so far this year, starting with Tropical Storm Ana in May.
If more storms form, the National Weather Service will move on to a list of supplemental names, only the third time in history it has had to do that. The first was in 2005.
Wanda is not expected to pose any danger to land, the National Hurricane Center said on Sunday.
It was located about 900 miles west of the Azores, with maximum sustained winds of 50 miles per hour, forecasters said. The storm was moving west and was expected to make a slow, nearly 180-degree turn to the south, the east and then northeast through Tuesday before weakening, forecasters said.
Last year’s season saw a record-breaking 30 named storms, including six major hurricanes, forcing meteorologists to use Greek letters to identify the final nine storms.
But in March, citing confusion among the general public, the World Meteorological Organization said it would no longer use the Greek alphabet to label storms and would instead rely on a supplemental list of 21 names, beginning with Adria, Braylen and Caridad, and ending with Viviana and Will.
“Zeta, Eta, Theta — if you think about even me saying those — to have those storms at the same time was tough,” Kenneth Graham, the director of the National Hurricane Center, said this year. “People were mixing the storms up.”
Like the main list of storm names, the supplemental list does not include names that begin with the letters Q, U, X, Y or Z, which officials said were not common enough or easily understood across English, Spanish, French and Portuguese, the languages frequently spoken throughout North America, Central America and the Caribbean.
The links between hurricanes and climate change are becoming more apparent. A warming planet can expect stronger hurricanes over time, and a higher incidence of the most powerful storms. But the overall number of storms could drop, because factors like stronger wind shear could keep weaker storms from forming.
Hurricanes are also becoming wetter because of more water vapor in the warmer atmosphere. Scientists have suggested storms like Hurricane Harvey in 2017 produced far more rain than they would have without the human effects on climate. Also, rising sea levels are contributing to higher storm surge — the most destructive element of tropical cyclones.
Ana became the first named storm of the season on May 22, making this the seventh year in a row that a named storm developed in the Atlantic before the official start of the season on June 1.
In May, scientists with the National Oceanic and Atmospheric Administration forecast that there would be 13 to 20 named storms this year, six to 10 of which would be hurricanes, including three to five major hurricanes of Category 3 or higher in the Atlantic.
NOAA updated its forecast in early August, predicting 15 to 21 named storms, including seven to 10 hurricanes, by the end of the season on Nov. 30. With Wanda, there have been 21 named storms so far, and seven of them became hurricanes.
Neil Vigdor contributed reporting.