Allowing for forecast uncertainties, seasonal hurricane forecasters estimate a 70 percent chance of 9 to 15 named storms, which includes 4 to 8 hurricanes, of which 1 to 3 are expected to become major hurricanes (category 3, 4 or 5 on the Saffir-Simpson scale).

An average Eastern Pacific hurricane season produces 15 to 16 named storms, with nine becoming hurricanes and four to five becoming major hurricanes. The Eastern Pacific hurricane season runs from May 15 through Nov. 30, with peak activity from July through September.

The main climate factors influencing this year's Eastern Pacific outlook are the atmospheric conditions that have decreased hurricane activity over the Eastern Pacific Ocean since 1995 -- and the fact that El Niño has faded.

"La Niña is becoming increasingly likely, which further raises the chance of a below-normal season for the Eastern Pacific region," said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA's Climate Prediction Center.

The outlook is a general guide to the overall seasonal hurricane activity. It does not predict whether, where or when any of these storms may hit land.

Eastern Pacific tropical storms most often track westward over open waters, sometimes reaching Hawaii and beyond. However, some occasionally head toward the northeast and may bring rainfall to the arid southwestern United States during the summer months. Also, during any given season, two to three tropical storms can affect western Mexico or Central America. Residents, businesses and government agencies of coastal and near-coastal regions should always prepare prior to each and every hurricane season regardless of the seasonal hurricane outlook.

Note: If no author is given, the source is cited instead.

• Hurricanes and Cyclones
• Severe Weather
• Weather
• Storms
• Climate
• Geography

• National Hurricane Center
• List of Category 5 Pacific hurricanes
• List of major natural disasters in the United States
• Typhoon Tip
• 1997 Pacific typhoon season
• Hurricane Opal