Above average Atlantic hurricane season predicted in early forecasts

The bad news is that Colorado State University (CSU) weather gurus Phil Klotzbach and William Gray are predicting a turbulent, above-average storm season. The worse news is that several other prominent climatologists agree.

The CSU tropical research experts, in a pre-season forecast released yesterday, predicted 18 named storms, including nine hurricanes, four of which would be major.

This compares with an average season’s tally of 12 storms, including six hurricanes, three with winds greater than 110 mph.

According to the two CSU climatologists, the tropical Atlantic is unusually warm and El Niño, the atmospheric force that inhibits storm formation, is unlikely to emerge this season, which runs through November 30.

“Typically, El Nino is associated with stronger vertical shear across the tropical Atlantic, creating conditions less conducive for storm formation,” Klotzbach said.

The two experts also noted that the Atlantic basin remains in an era of tropical intensity, where more hurricanes tend to form, the result of a natural cycle.

Adding his comments on El Nino, Jeff Masters, chief meteorologist of online weather site Weather Underground, said years where neither El Niño nor its polar opposite, La Niña, emerge can be highly active.

“Remember the neutral El Niño year of 2005?” he said, referring to the season when 28 storms, including 15 hurricanes, formed.

While the numbers of storms  Klotzbach and Gray predict are rarely right on target, they have accurately predicted when a season would be more or less active than normal in four of the past five years.

The two CSU experts were off-track with their initial prediction for 2012 last April, calling for a considerably slower than normal season. Like other prediction teams, they thought El Niño would arise by the heart of the season.

They were all wrong, however, and the year ended with 19 named storms, including 10 hurricanes, making it the third busiest season on record.

Respected forecasters Tropical Storm Risk (TSR) are also expecting an above average season this year. They predict 15 named tropical storms, 8 of which will become hurricanes and 3 of which will attain Category 3 status or higher becoming major hurricanes.

This is about 30 percent above the average storm formation levels and TSR said that it puts the above average nature of the 2013 hurricane season down to two factors.

Firstly, the forecast models suggest lighter than normal trade winds across the Caribbean Sea and tropical north Atlantic which can help to influence the cyclonic vorticity, or spinning up, of storms which can help to increase intensification.

Second is the long-range forecast for slightly warmer than normal sea surface temperatures in the Atlantic’s main hurricane development zones during the peak months of August and September, again a factor that could help to intensify storms and cause more to form.

Meanwhile, Weatherbell, a private firm that employs well-known forecaster Joe Bastardi, is calling for 16 named tropical storms, a very high 12 hurricanes, and 5 hurricanes reaching major status of Category 3 or higher.Bastardi also emphasizes the warmer than average sea surface temperatures in the Atlantic ocean, saying that 2013 could be a very dangerous hurricane year for the Caribbean and the southeast United States. He also forecasts above average activity up the east coast and into the Gulf and further west.

The Weatherbell expert believes that 2013 will see hurricane activity shift back to the traditional paths we know from seasons such as 2004 and 2005, with hurricanes tracking a little further south than in 2012.

Adding another prediction, Weather Services International has just published its early season Atlantic hurricane forecast for 16 named storms, 9 hurricanes and 5 major hurricanes.

Several other forecast teams are expected to release seasonal outlooks over the next two months, including AccuWeather.com and WSI, a part of The Weather Channel. The National Oceanic and Atmospheric Administration (NOAA) will release its predictions on May 23.

Reprinted from Caribbean360

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