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NOAA Magazine || NOAA Home Page CONDITIONS FUEL EL NIÑO DEVELOPMENT
In this month's El Niño/Southern Oscillation Diagnostic Discussion, NOAA scientists report that a climate phenomenon called the Madden-Julian Oscillation contributed to an increase in ocean surface temperatures late last month. Ocean surface temperatures of 1 degree C (2 degrees F) above average were observed throughout most of the equatorial Pacific at the end of May. This increase in ocean temperature, combined with observations of abnormally heavy rainfall in parts of South America, and the lack of it over Indonesia suggests that El Niño continues to develop as was originally forecast. "The MJO is an important factor contributing to the evolution of El Niño because it can influence the winds near the Earth's surface. In late May, the MJO contributed to a weakening of the normal east-to-west flow throughout the equatorial Pacific, which has led to an increase in ocean surface temperatures," said Vernon Kousky, meteorologist at NOAA's Climate Prediction Center. "With last month's MJO activity, we saw signs of the further developing El Niño, but it is not unusual to see a cycle during which conditions intensify, wane, then intensify again," he said. "The overall trend, though, together with changes in weather and pressure patterns in key regions of the tropics that are characteristic of El Niño, suggest that further development towards a weak-to-moderate El Niño will continue during the remainder of 2002." El Niño does not significantly impact the U.S. during summer. Although it does historically tend to suppress Atlantic hurricane activity. NOAA forecasters indicate that El Niño likely will not be strong enough to affect hurricane activity this year, especially early in the season. If El Niño continues to develop as expected, there is a possibility that fewer hurricanes than normal may form in the Atlantic during August to October, the peak of Atlantic hurricane season. NOAA will update the 2002 Atlantic hurricane season outlook in early August. NOAA will continue to monitor the evolution of El Niño and provide monthly updates. NOAA scientists assert the actual global impacts of the forecasted weak or moderate El Niño should be considerably weaker than those experienced during the very strong 1997-98 El Niño. The El Niño/Southern Oscillation Diagnostic Discussion is a team effort consisting of NOAA's Climate Prediction Center (lead), Climate Diagnostics Center, Geophysical Fluid Dynamics Laboratory, National Climatic Data Center, Atlantic Oceanographic and Meteorological Laboratory, and the International Research Institute for Climate Prediction. NOAA's Climate Prediction Center is an organization of the National Weather Service. NOAA's National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. NOAA National Weather Service operates the most advanced weather and flood warning and forecast system in the world, helping to protect lives and property and enhance the national economy. Relevant Web Sites ENSO Frequently Asked Questions Sea Surface Temperature Outlook ENSO Impacts by Region
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