Hurricane seasons — beginning May 15 in the eastern Pacific and June 1 in the Atlantic, and ending November 30 — are assessed before the start of the season in terms of how many storms will occur relative to a normal or "neutral" year. An "average" season sees 10 storms, six hurricanes and two major hurricanes.

Four times a year, the Tropical Meteorology Project, led by Dr. William Gray of the Department of Atmospheric Science at Colorado State University, produces outlooks for the coming hurricane season.

• For Dr. Gray's latest Atlantic season forecast, visit the Project's website.

Every May and August, hurricane forecasters at the National Oceanic and Atmospheric Administration (NOAA) issue their own hurricane season outlook.

• For NOAA's latest hurricane season forecast, visit NOAA's website.

The ability to forecast storms at such a macro level is a result of today's improved understanding of global weather phenomena. Two such phenomena, El Niño and La Niña, are patterns of surface temperature anamolies occurring in the eastern and central Pacific Ocean. Both El Niño, an episode of abnormally warm surface temparatures, and La Niña, an episode of cold temperatures, have great influence on the global weather patterns including the ability to shift temperature and precipitation throughout the world.

El Niño and La Niña may influence hurricane activity in both the eastern Pacific and Atlantic. This direct link between surface temperatures in the Pacific and Atlantic hurricane activity is based on the way winds move as a result of this change in temperature at the ocean surface. In an El Niño year, strong west-to-east winds move across the Caribbean Sea and tropical Atlantic Ocean, which can have an effect of weakening or killing hurricanes. La Niña, the opposite weather effect, may therefore result in a higher-than-usual number of hurricanes