WSET.com - ABC13CSU Forecasts Above Average Hurricane Season by Lyndsay Tapasas

There are just under two months to go until the start of the 2011 Hurricane season. Although 2010 was an above-average season overall (officially 196% of average) the United States was very lucky in that the impact from tropical systems was very minimal. Colorado State University has revised their outlook for the 2011 season (the first outlook was initially issued in December) and is calling for a season 175% of average.

The team is calling for 16 named storms, nine of which are expected to develop into hurricanes, with five of those nine becoming major hurricanes (sustained winds of at least 111mph-- category 3, 4, or 5). Other highlights of the forecast include:

- A 72 percent chance that at least one major hurricane will make landfall on the U.S. coastline (the long-term average probability is 52 percent).

- A 48 percent chance that a major hurricane will make landfall on the U.S. East Coast, including the Florida Peninsula (the long-term average is 31 percent).

- A 47 percent chance that a major hurricane will make landfall on the Gulf Coast from the Florida Panhandle west to Brownsville (the long-term average is 30 percent).

One of the most critical factors going into this forecast is the El Niño/La Niña oscillation, which many of you may have heard of. La Niña or neutral conditions promote very active Atlantic hurricane seasons, while an El Niño sharply reduces Atlantic hurricane activity (because of increased wind shear). The current La Niña is expected to weaken and become near-neutral as we enter the hurricane season, but NOT transition to an El Niño.

This, in addition to a warm anomaly of sea surface temperatures in the Tropical Atlantic, are two of the key factors in forecasting an above-average season.