For the entire six-month season, which begins 1 June, NOAA’s Climate Prediction Center says there’s a 70% chance of 9 to 15 named storms (with top winds of 39 mph or higher), of which four to eight will strengthen to a hurricane (with top winds of 74 mph or higher) and of those one to three will become major hurricanes (with top winds of 111 mph or higher, ranking Category 3, 4 or 5).

Based on the period 1981-2010, an average season produces 12 named storms with six hurricanes, including three major hurricanes.

Favoring storm development in 2012 is the continuation of the overall conditions associated with the Atlantic high-activity era that began in 1995, in addition to near-average sea surface temperatures across much of the tropical Atlantic Ocean and Caribbean Sea, known as the Main Development Region. Two factors now in place that can limit storm development, if they persist, are: strong wind shear, which is hostile to hurricane formation in the Main Development Region, and cooler sea surface temperatures in the far eastern Atlantic.

Another potentially competing climate factor would be El Niño if it develops by late summer to early fall. In that case, conditions could be less conducive for hurricane formation and intensification during the peak months (August-October) of the season, possibly shifting the activity toward the lower end of the predicted range.

—Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center

NOAA this season is introducing enhancements to two of the computer models available to hurricane forecasters—the Hurricane Weather Research and Forecasting (HWRF) and the Geophysical Fluid Dynamics Laboratory (GFDL) models. The HWRF model has been upgraded with a higher resolution and improved atmospheric physics. This latest version has demonstrated a 20–25% improvement in track forecasts and a 15% improvement in intensity forecasts relative to the previous version while also showing improvement in the representation of storm structure and size. Improvements to the GFDL model for 2012 include physics upgrades that are expected to reduce or eliminate a high bias in the model's intensity forecasts.

The seasonal outlook does not predict how many storms will hit land. Forecasts for individual storms and their impacts are provided by NOAA’s National Hurricane Center, which continuously monitors the tropics for storm development and tracking throughout the season using an array of tools including satellites, advance computer modeling, hurricane hunter aircraft, and land- and ocean-based observations sources such as radars and buoys.

NOAA will issue an updated seasonal outlook for the Atlantic hurricane season in early August, just prior to the historical peak of the season.