Where are the hurricanes?
It’s going to be a bad year for hurricanes along the coasts of the United States. That’s what forecasters, including Colorado State University meteorologists William Gray and Phil Klotzbach, were saying last year when they predicted we’d see 12 named storms this hurricane season.
The tally so far? Zero.
An average Atlantic hurricane season, which runs from June 1 to Nov. 30, produces 11 named storms, with six becoming hurricanes, according to the National Oceanic and Atmospheric Administration (NOAA).
But this year, more than two months into the season, no storms or hurricanes have yet formed.
We can thank El-Niño for that, scientists say.
In an update issued last week, “NOAA is calling for an increased probability of a below-average season,” said Dennis Feltgen, a meteorologist with the National Hurricane Center. “This is due primarily to the formation of El-Niño.”
El-Niño is an abnormal warming of Pacific Ocean currents that occurs every three to five years, often bringing with it dramatic global weather changes, like heavy, flood-inducing rainfall (and intense heat, as it did in the US in 2006, the hottest year recorded in the United States).
It also tends to dampen hurricane activity in the Atlantic. Here’s how: In El-Niño years, the warming Pacific causes the jet stream, a narrow channel of strong horizontal winds, to shift southward. As the jet stream winds blow over the Atlantic Basin (which include the Caribbean Sea and Gulf of Mexico), it creates wind shear, a sharp shift in wind patterns. That change in wind patterns upsets hurricane development, leading to fewer storms.
"[El-Niño] helps to reduce hurricane activity by blowing away the tops of growing thunderstorms that would normally lead to tropical storms,” said Mr. Feltgen in an e-mail.
Nonetheless, he urges caution. “Our message is, it only takes one storm to make it a bad year for you, and it is the one storm you need to prepare for.”
NOAA’s updated prediction for the 2009 season is:
• seven to 11 named storms.
• three to six hurricanes.
• one to two major hurricanes (Category 3, 4, or 5).
As you might guess, the record of accuracy varies, according to Reuters.