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2010 hurricane season predictions scatter all over the map

Days after the 2009 hurricane season ended, two of the country's leading hurricane experts delivered this grim news:

The 2010 Atlantic season doesn't look good. Anticipate an above-average probability of major hurricane landfall, with 11 to 16 named storms, six to nine hurricanes and as many as five that could become major hurricanes.

True, that prediction is very similar to the over-estimations we've seen over the last few years. And even Colorado State University's Dr. Bill Gray and Dr. Phil Klotzbach, who put out the December forecast, admit it's impossible to predict potential hurricane activity this early.

So why even issue such a report?

"Well, that's a significant debate that I've been involved in myself," said Klotzbach.

It's also a question that cracks open the complicated and often confusing world of hurricane predictions and climatology. As more is understood about global climate conditions and computer models become more sophisticated, hurricane experts have felt pressure to release early findings to an information-hungry public.

But a lot of that information is far too preliminary and inaccurate, said Bay News 9 chief meteorologist Mike Clay, and it's often overplayed by the media.

"The December reports aren't useful and they don't mean anything," Clay said. "And the problem is, people in Florida just don't want to hear about it."

The National Oceanic and Atmospheric Administration, perhaps the world's top source for hurricane information, also issues early forecasts in May. But meteorologists there prefer to downplay the preseason reports and instead point to forecasts in August — halfway into the season — as examples of NOAA's accuracy.

"With a lot of hurricane awareness heating up before the season, it certainly makes sense to put out an early report," said Dr. Gerry Bell, NOAA's lead Atlantic hurricane seasonal forecaster. "But in August, that's when you really have the best handle on it. With August outlooks, we were right within our predicted range nine out of 12 times."

Bell said NOAA forecasters don't look at the Colorado State team's early reports, and sometimes the two institutes differ widely in their predictions. But all meteorologists study more or less the same factors in predicting how active 2010's season will be.

If El Niño conditions dissipate, as they typically do within a year, wind shear will be reduced, making it easier for hurricanes to form. If El Niño immediately transitions into La Niña, we could see extremely active hurricane season.

Or, if El Niño lasts longer than normal, we could have another quiet season, like this past one.

It's just too early to say what El Niño will do, experts agree.

But it's not too early to guess based on what has happened in past seasons, which is how Gray and Klotzbach come up with what they call "hindcasts."

"We basically assume the future will turn out like the past," Klotzbach said.

And that involves going deep in the past and seeing patterns of cycles that last 25 to 40 years.

While statistical data and wind measurements were sketchy prior to 1950, scientists know that Atlantic waters were generally cooler than normal from about 1900 to 1930. Then, from the mid 1930s to about 1970, the waters were warmer. From 1971 to 1994, the waters were general cool.

Now, say Klotzbach and NOAA's Bell, we're in another warm period that began in 1995, and thus, the Atlantic hurricane season is likely to be more active than normal for perhaps another decade or two. These relatively calm seasons we've seen over the last few years have been either anomalies or the products of El Niño.

But even those facts are open for debate by other scientists.

Dr. Peter Ray, a meteorology professor at Florida State University who independently studies hurricanes, believes we are actually entering a less active season based on his studies about Atlantic warm pools.

Warm pools are wide regions of sea surface temperatures warmer than 28.5 degrees Celsius, or about 83 degrees Fahrenheit. Hurricanes generally require water temperatures of at least 79 degrees. And the bigger the warm pool, the more active a hurricane season.

The lack of a warm pool, along with the increased wind shear because of El Niño, is why we had a quiet 2009, Ray said. He expects the lack of a warm pool to continue, cutting down on hurricanes for years to come.

Ray believes he's more willing to go out on a limb and say so because, unlike NOAA and Colorado State forecasters, he doesn't have the pressure to issue public safety warnings.

Like the other meteorologists, he issued his prediction with the caveat that nature is tricky, and only one kind of forecast is 100 percent.

"Everyone's right the day of the landfall," Ray said.

Emily Nipps can be reached at nipps@sptimes.com or (727) 893-8452.

How it works

Meteorologists study these factors to predict how active 2010's season will be:

• If El Niño conditions dissipate, wind shear will be reduced, making it easier for hurricanes to form.

• If El Niño immediately transitions into La Niña, we could see an extremely active hurricane season.

• If El Niño lasts longer than normal, we could have another quiet season.

2010 hurricane season predictions scatter all over the map 12/19/09 [Last modified: Saturday, December 19, 2009 11:05pm]

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