Experts Predict Another Active Hurricane Season, More Impact on US

The hurricane season doesn't officially begin until June 1, but private forecasters already have issued their outlooks for the Atlantic Basin, predicting an active season and the potential for greater impact on the U.S. mainland than last year.

The 2010 Atlantic hurricane season was the third most active on record in terms of the number of named storms, but the 19 tropical storms and hurricanes had little direct impact on the United States.

Last year, both AccuWeather and the Tropical Meteorology Project accurately predicted the active season, but over-predicted the U.S. impact. In April 2010, the Tropical Meteorology Project predicted 15 named storms, with a 95 percent chance of a hurricane making landfall in the U.S. AccuWeather predicted 16 to 18 named storms, including two or three major hurricanes for the U.S.

AccuWeather, in an outlook issued last week by meteorologist and hurricane forecaster Paul Pastelok, is calling for 15 named storms this year, including eight hurricanes and three major hurricanes (Category 3 or higher). The Tropical Meteorology Project expects 16 named storms, including nine hurricanes and five major hurricanes, in its updated forecast, which was released today. The initial forecast, issued in December, had been for 17 named storms.

The 1961-2009 average, according to the National Hurricane Center, is 11.3 named storms, including 6.2 hurricanes and 2.3 major hurricanes. The official U.S. government Atlantic hurricane season forecast will be issued in the latter half of May.



AccuWeather believes the early-season threat will be greatest in the southern Caribbean and western Gulf of Mexico. The threat is expected to shift to the eastern Caribbean and eastern Gulf of Mexico during the middle and latter parts of the season, with the highest threat in South Florida and the eastern Carolinas. Late-season landfalls are considered a threat even in areas far north, including northern New England and the Canadian Maritimes.

The storm track predictions are based, in part, on the expected strength and positions of high-pressure systems over the Atlantic and comparisons to other seasons with similar overall environmental conditions.

The Tropical Meteorology Project, headed by William Gray and Phil Klotzbach, is less specific on potential landfall areas, but is predicting a higher than normal likelihood of landfall along the Gulf Coast, Florida and the U.S. East Coast and the Caribbean. This includes a 72 percent likelihood of at least one major hurricane hitting the Atlantic Basin coastal regions of the U.S., compared with an average probability of 52 percent for the last century.

The threat of a major hurricane is fairly evenly divided among U.S. regions -- 48 percent for the U.S. East Coast and Florida and 47 percent for the Gulf Coast from the Florida Panhandle westward to Brownsville, Texas. This is higher than the average for the past century, which is approximately 30 percent for all regions. The probability of at least one major hurricane in the Caribbean is 61 percent, compared with a last-century average of 42 percent.

Conditions factoring into the forecast of an active season include the continuation of the Atlantic Multi-Decadal Oscillation, an extended period of time when hurricane development is heightened by a number of meteorological conditions. The current cycle began in 1995. While seasonal variations occur within this period, the overall trend has been for greater than normal hurricane activity during this cycle.

This season, Atlantic Basin sea-surface temperatures are expected to be warmer than average but cooler than last season.

Another factor considered in the seasonal forecast is the expected lack of an El Nino or La Nina. El Nino, which is a warming of the water in the equatorial region of the Pacific Ocean, typically results in less hurricane activity in the Atlantic Basin. A La Nina, which is a cooling of the water in the same region, typically means more activity than normal in the Atlantic Basin.

The development of a La Nina last year is believed to have been part of the reason for the active season. The La Nina has also influenced the weather during the winter and spring, but forecasters at the federal government's Climate Prediction Center expect it to dissipate by summer. The lack of a La Nina will likely mean fewer storms overall, compared with last year.

AccuWeather is a private forecasting company based in State College, Pa. The Tropical Meteorology Project is associated with Colorado State University, but the forecast is supported by private and personal funds.