NOAA scientists have announced the arrival of El Nino, a climate phenomenon with a significant influence on global weather, ocean conditions and marine fisheries. El Nino, the periodic warming of central and eastern tropical Pacific waters, occurs on average every two to five years and typically lasts about 12 months. NOAA expects this El Nino to continue developing during the next several months, with further strengthening possible. The event is expected to last through winter 2009-10.
El Nino’s impacts depend on a variety of factors, such as intensity and extent of ocean warming, and the time of year. Contrary to popular belief, not all effects are negative. On the positive side, El Nino can help to suppress Atlantic hurricane activity. In the United States, it typically brings beneficial winter precipitation to the arid Southwest, less wintry weather across the North and a reduced risk of Florida wildfires. Its negative impacts have included damaging winter storms in California and increased storminess across the southern U.S.
