El Niño has officially returned, and that could be good news for Florida.
It means more frequent and heavy rainfall on our state, particularly during winter, but it also can mean fewer hurricanes.
That's one of the few favorable effects of El Niño, which gets blamed for everything from floods in Peru to mudslides in California and brush fires in Australia.
"For Florida, there's actually more chance of winter precipitation and a decrease in wildfires," said Dr. Gerry Bell, a meteorologist for the National Weather Service's Climate Prediction Center. "And El Niño tends to increase wind shear over the Atlantic, making conditions for hurricanes less favorable."
This might explain why we're a month and a half into the 2009 hurricane season and we haven't even seen our first named storm. By the time July ended last year, four named storms, including a hurricane, already had formed in the Atlantic.
A true El Niño event, said to occur every three to five years, is a pattern of above-average warm temperatures in the eastern Pacific Ocean. This warmth tends to drive strong winds into the upper atmosphere and over the Atlantic, making it harder for tropical storms and hurricanes to form.
When those Pacific waters cool to below-average temperatures, the opposite happens, causing La Niña conditions: drier summers and warmer winters in the southeast United States, while the Pacific Northwest is more likely to be wetter than normal in the late fall and early winter. La Niña can also mean a more active Atlantic hurricane season.
An El Niño means 36 percent fewer named storms in the Atlantic basin than in La Niña years, and storms' intensities are 6 percent lower, according to National Oceanic and Atmospheric Administration data compiled between 1899 to 1996.
Over the past 150 years, hurricane damage has averaged $800 million year during El Niño years and double that during La Niña years, according to Jeff Masters of Weather Underground (wunderground.com).
However, experts warn, every El Niño and La Niña is different. Sometimes drastically so.
The 2004 hurricane season, which hammered Florida with Ivan, Frances, Jeanne and Charley and killed over 3,000 people worldwide, was an El Niño year.
Georgia Tech researchers recently released a study that tried to explain the anomalous El Niño years. It pointed to the occasional shifting — or perhaps entirely separate — pattern of the warm sea-surface temperatures from the eastern Pacific to the central Pacific.
But most meteorologists believe more research needs to be done before using that theory to predict hurricane seasons.
"Bottom line is that all El Niños are not the same," Bell said.
People shouldn't be relying on El Niño to keep them safe this season, he said, noting that we still are in a decades-long period of higher hurricane activity in the Atlantic basin. Most experts predict 11 or 12 tropical storms for 2009, with six becoming hurricanes, two becoming Category 3 or higher.
Even if fewer hurricanes threaten Florida this season, Bell said, it only takes one to make it memorable. And it's still early.
Emily Nipps can be reached at [email protected] or (727) 893-8452.