The North Atlantic hurricane season will likely be an average one this year as surface temperatures in the western Pacific Ocean hover in a neutral position between a departing La Nina period and an approaching El Nino phase.
Eqecat experts gave their views of the 2012 North Atlantic and Eastern Pacific tropical storm scenarios in a webinar in which they also said the company will unveil major updates to its catastrophe modeling platform RQE (Risk Qualification and Engineering). Version 13 of the platform will be unveiled in the fall of 2012, said product manager Aarti Dinesh during the webinar.
"This will be taking it to a new level which makes the uncertainties transparent," said Dinesh, who added that Eqecat will unveil updates to all 77 of its peril model updates at the same time.
According to Eqecat, the new platform will replace its WorldCatenterprise platform. RQE v.13 "is the result of a three-year initiative that involved a significant degree of collaboration with clients, prospects, and industry experts, and is "the single largest release of its kind," the company said.
John Mangano, a research scientist with Eqecat, said in the webinar that the North Atlantic hurricane season will likely be an average one, "mainly driven by El Nino."
Pointing out that the long-range oscillations including El Nino (Pacific warming) and La Nina (Pacific cooling), which can last 2 to 7 years, are "a big factor in pre-season Atlantic windstorm predictions."
El Nino conditions generate wind shear into the western Atlantic that dampens developing tropical storms, he said. In the Pacific, El Nino causes storms to develop further away from Australia and East Asia, giving them more time to form and develop into strong storms.
"The recent La Nina has ended and we're now in a neutral phase," said Mangano. "We may have an El Nino now forming off the coast of South America."
He added that as of June, sea surface temperatures in the western Pacific Ocean indicate that neutral phased, while a composite of weather models shows that more than half of then predict warming to an El Nino phase later this year.
"Hurricane landfalls four times as likely during the cool La Nina phase as during the warm El Nino phase," said Mangano.
According to Mangano, the paths taken by Atlantic hurricanes also depend in part on the Azores-Bermuda High, a semi-permanent area of high atmospheric pressure in the Atlantic south of the Azores Islands and east of Bermuda.
If the Azores-Bermuda High expands and moves toward Bermuda, storms churning to the south of it will be forced on a more westerly path that will take them to the Caribbean and southern United States. If the High shifts away from Bermuda, storms tend to curve north and stay out to sea.
Mangano said the movements of the Azores-Bermuda High are unfortunately harder to predict, making it a less reliable long-term forecasting tool.