While they still anticipate slightly below-average activity for the 2012 Atlantic hurricane season, forecasters at Colorado State University (CSU) now expect more named storms and hurricanes than they did in April due to "large amounts of uncertainty in both the phase of ENSO [the El Nino-Southern Oscillation] as well as in Atlantic Basin conditions."

In an extended range forecast issued Friday the CSU forecast team said it expects 13 named storms in the Atlantic Basin this year, including five hurricanes, two of them major (Category 3 or higher). In April the CSU forecast was 10 named storms, including four hurricanes, two of them major (see Daily GPI, April 16).

"We have increased our numbers slightly from our early April forecast, due largely to our uncertainty as to whether an El Nino will develop later this summer and to marginal Atlantic Basin conditions," the CSU team said.

The Atlantic hurricane season, which officially runs from June 1 to Nov. 30, got off to an early start this year with the formation of Tropical Storms Alberto and Beryl in May. The CSU team included Alberto and Beryl in its latest forecast numbers but said that historically pre-June 1 activity "has very little bearing" on the rest of the Atlantic hurricane season.

"The only two seasons on record with two named storms prior to 1 June were 1887 and 1908. While 1887 was a very active season, 1908 had average levels of activity," they said.

The consensus forecast this year has been that the hurricane season is likely to produce fewer tropical storms than the last few years. Forecasters at the National Oceanic and Atmospheric Administration (NOAA) have said there is a 70% chance of nine to 15 named storms in the Atlantic Basin, including four to eight hurricanes, with one to three major hurricanes, compared with the 1981-2010 average of 12 named storms, six of them hurricanes, including three major hurricanes (see Daily GPI, May 25). The WeatherBug meteorology team is forecasting 11 to 13 named storms, including six to seven hurricanes, with two to four major hurricanes, while Telvent DTN said it is expecting 11 named storms, including six hurricanes, two of them major (see Daily GPI, May 24).

Other forecasters expecting a relatively quiet hurricane season this year include Weather Services International [forecasting 11/six/two (see Daily GPI, May 23)] and AccuWeather [12/five/two (see Daily GPI, April 27)].

The CSU team said it anticipates a slightly below-average probability of United States and Caribbean major hurricane landfall. There is a 28% probability of a major hurricane making landfall on the Gulf Coast from the Florida panhandle west to Brownsville, TX; a 28% probability of a major hurricane making landfall on the East Coast; and a 48% probability of major hurricane coming ashore anywhere on the U.S. coastline -- all below the average over the last century -- the forecasters said. The probability of at least one major hurricane entering the Caribbean is 39%, compared to 42% for the last century.

While last year's Atlantic hurricane season didn't bring many tropical storms to Gulf of Mexico energy interests or the North American mainland, it did produce the third-highest number of tropical storms since records began in 1851 and continued a trend of active hurricane seasons begun in 1995 (see Daily GPI, Nov. 29, 2011).

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