El Niño Makes a Comeback

El Niño conditions have developed in the tropical Pacific and are likely to continue into early 2007
September 30, 2006

El Niño Makes a Comeback

Scientists at the NOAA Climate Prediction Center reported that El Niño conditions have developed in the tropical Pacific and are likely to continue into early 2007.

Ocean temperatures increased remarkably in the equatorial Pacific during the first two weeks of September.

"Currently, weak El Niño conditions exist, but there is a potential for this event to strengthen into a moderate event by winter," said Vernon Kousky, NOAA's lead El Niño forecaster.

Some impacts from the developing El Niño are already evident in the pattern of tropical precipitation. During the last 30 days, drier-than-average conditions have been observed across all of Indonesia, Malaysia and most of the Philippines, which are usually the first areas to experience ENSO-related impacts. This dryness can be expected to continue, on average, for the remainder of 2006.

Also, the development of weak El Niño conditions helps explain why this Atlantic hurricane season has been less active than was previously expected. El Niño typically acts to suppress hurricane activity by increasing the vertical wind shear over the Caribbean Sea region. However, at this time the El Niño impacts on Atlantic hurricanes are small. "We are still in the peak months of the Atlantic hurricane season, and conditions remain generally conducive for hurricane formation," said Gerry Bell, NOAA's lead seasonal hurricane forecaster.

Typical El Niño effects are likely to develop over North America during the upcoming winter season. Those include warmer-than-average temperatures over western and central Canada, and over the western and northern United States. Wetter-than-average conditions are likely over portions of the U.S. Gulf Coast and Florida, while drier-than-average conditions can be expected in the Ohio Valley and the Pacific Northwest.

The term El Niño refers to the large-scale ocean-atmosphere climate phenomenon linked to a periodic warming in sea surface temperatures across the central and east-central equatorial Pacific (between approximately the date line and 120 degrees west). El Niño represents the warm phase of the El Niño/Southern Oscillation, or ENSO, cycle, and is sometimes referred to as a Pacific warm episode. El Niño originally referred to an annual warming of sea surface temperatures along the west coast of tropical South America.

In 2007 NOAA, an agency of the U.S. Commerce Department, celebrates 200 years of science and service to the nation. Starting with the establishment of the U.S. Coast and Geodetic Survey in 1807 by Thomas Jefferson much of America's scientific heritage is rooted in NOAA. The agency is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of the nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 60 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.

Relevant Web Sites
El Niño/southern Oscillation (ENSO) Diagnostic Discussion

Weekly Update: ENSO Cycle: Recent Evolution, Current Status and Predictions (PowerPoint)

NOAA’s El Niño Southern Oscillation