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NOAA satellite image of Tropical Storm Ernesto taken on Aug. 31, 2006, at 10:45 a.m. EDT.Nov. 30, 2006 As the 2006 Atlantic hurricane season comes to a close today, NOAA scientists announced that seasonal activity was lower than expected due to the rapid development of El Niño—a periodic warming of the ocean waters in the central and eastern equatorial Pacific, which influences pressure and wind patterns across the tropical Atlantic. (Click NOAA satellite image for larger view of Tropical Storm Ernesto taken on Aug. 31, 2006, at 10:45 a.m. EDT. Click here for high resolution version. Please credit “NOAA.”)

The 2006 Atlantic hurricane season produced near-normal activity with a total of nine named storms, including five hurricanes, two of which became major hurricanes of Category 3 strength or higher. An average Atlantic hurricane season has 11 named storms, with six becoming hurricanes and two becoming major hurricanes. Unlike the past three seasons, the stronger hurricanes stayed well out at sea, sparing the Americas and the Caribbean islands from major hurricane damage this season.

NOAA image of explanation as to why the 2006 Atlantic hurricane season turned out less active than predicted.“The development of El Niño conditions by September helps explain why this Atlantic hurricane season was less active than predicted,” said Gerry Bell, NOAA’s lead forecaster on the Atlantic hurricane seasonal outlook team. “El Niño developed quickly and the atmosphere responded rapidly, reducing hurricane activity during an otherwise active era that began in 1995.” (Click NOAA image for larger view of explanation as to why the 2006 Atlantic hurricane season turned out less active than predicted. Click here for high resolution version. Please credit “NOAA.”)

El Niño, combined with the large-scale weather patterns over the southeastern U.S., produced sinking air in the middle and upper atmosphere, along with higher than anticipated wind shear (the change in winds through the atmosphere) over the Atlantic Ocean, Gulf of Mexico and Caribbean Sea. These conditions minimized thunderstorm activity, which inhibited tropical storm and hurricane formation.

Analysis by NOAA scientists has linked El Niño’s rapid development and intensification to a series of large subsurface ocean waves that affect ocean temperatures, which began in June. These waves produced a progressive warming of the tropical Pacific Ocean during the summer months. A particularly strong wave led to a significant warming of the entire eastern half of the equatorial Pacific in early September. This led NOAA in early September to report that an El Niño had developed. These warmer waters produced enhanced rainfall near the international date line, resulting in suppressed hurricane activity.

“Getting a quick handle on El Niño events, which rapidly intensify, is essential for predicting seasonal hurricane activity,” said Bell. “The last time we had a rapidly developing El Niño was during the 2002 hurricane season, which also led to near-normal activity. NOAA continues to develop and improve climate models to better predict the onset of El Niño, its impacts on weather patterns in the United States and its effects on Atlantic hurricane activity.”

To detect and monitor the formation, duration and strength of El Niño, NOAA established the ENSO Observing System in 1994. Today’s operational system is based on work done by the Pacific Marine Environmental Laboratory, which is a branch of NOAA Research. The ENSO Observing system is an example of NOAA research activities being translated into operational forecast products. NOAA’s operational ENSO observing system includes the TAO/TRITON array of moored buoys and the Argo drift buoys that observe ocean patterns in conjunction with NOAA’s polar orbiting satellites. The satellites, in combination with the TOGA TAO operational array, are critical for allowing NOAA to monitor, assess and predict El Niño events. The data from the ocean observing system provides substantial benefit to both NOAA's research and operational forecasts of climate patterns that can strongly affect weather across the nation.

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
NOAA Atlantic Hurricane Outlook & Seasonal Climate Summary Archive

NOAA 2006 Atlantic Hurricane Season Reports

NOAA El Niño/Southern Oscillation (ENSO) Diagnostic Discussion

NOAA's Role in El Niño Research, Monitoring and Prediction

NOAA Climate Prediction Center

NOAA: El Niño Makes a Comeback

NOAA Hurricanes Portal

NOAA 2006 Storm Event Imagery

Media Contact:
Carmeyia Gillis, NOAA Climate Prediction Center, (301) 763-8000 ext. 7163