Meteorologists at Colorado State University and the National Oceanic and Atmospheric Administration think the 2017 Atlantic hurricane season could be an active one. CSU forecasters think 14 named tropical storms will form in the Atlantic Basin, which includes the Atlantic Ocean, Caribbean Sea and Gulf of Mexico.
The NOAA forecast covers a wider range of possibilities. During an average season, 12 named storms form. The NOAA forecast says that anywhere from 11 to 17 named storms will form in the Atlantic.
One named tropical storm, Arlene, has already formed and is included in the totals for both forecasts.
CSU forecasters think six of the storms will reach hurricane strength with winds of at least 74 mph. Two of those hurricanes could become major storms with winds exceeding 110 mph. The NOAA forecast predicts that five to nine hurricanes will form, with two to four becoming major hurricanes.
During an average season, six tropical storms intensify into hurricanes, and three of those storms become major hurricanes.
Klotzbach said the differences between the CSU and NOAA forecasts were more semantic than substantial.
“If you look at the midpoint of NOAA’s season forecasts and compare it with ours, our forecasts are fairly similar,” Klotzbach said.
Klotzbach said he and his mentor, the late William Gray, found it “easier to focus on the midpoint of the forecast to give the general public an idea of exactly what you are predicting. . . . At the end of the day, I think it’s a matter of personal preference.”
CSU’s preseason forecast, released in April, had predicted a relatively quiet summer, with 11 named storms forming. Klotzbach said two factors had changed since the earlier forecast was released April 6–water temperatures in the tropical Atlantic where hurricanes form are unusually warm and a meteorological phenomenon known as an El Niño seems less likely to occur.
Hurricanes draw their power from warm ocean water. CSU’s forecast notes that while water temperatures in the tropical Atlantic are unusually warm, the waters are cooler than usual in the North Atlantic.
An El Niño occurs when waters in the Pacific Ocean off Peru and Ecuador are warmer than usual. The occurrence of the event is irregular, and sometimes several years pass between occurrences. An El Niño causes stronger upper-level winds over the Atlantic that can make it difficult for hurricanes to form, and that can cause a quieter than usual hurricane season.
NOAA’s National Hurricane Center also will issue storm surge watches and warnings for the first time this summer. A storm surge is a mound of water created by a hurricane’s winds and forward motion. It is pushed ahead of the eye of the storm, and in very powerful hurricanes can reach more than 22 feet above normal sea level. More people are killed by hurricanes’ storm surges than are killed by its winds.
Hurricane season runs from June 1 to November 30, with hurricanes most likely to form around September 10.
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