NOAA 03-069
Contact: Carmeyia Gillis
NOAA News Releases 2003
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Below Average Eastern Pacific Hurricane Season Expected

The National Oceanic and Atmospheric Administration (NOAA) hurricane experts announce the debut of an experimental Eastern Pacific Hurricane Outlook. Scientists at NOAA call for 11-15 tropical storms (normal is 15), with 6-9 becoming hurricanes (normal is 9), and 2-5 becoming major hurricanes (normal is 4-5). NOAA is an agency of the U.S. Commerce Department.

Scientists at NOAA predict there is a 50 percent probability of a below normal eastern Pacific hurricane season during 2003, a 40 percent probability of a near-normal season, and a 10 percent probability of an above-normal season.

Similar to the Atlantic hurricane season, one of the major factors in eastern Pacific hurricane development is the El Niño/Southern Oscillation (ENSO) climate phenomenon (El Niño/ La Niña). This month, NOAA scientists continued to report the dominant trend is for cooling in the tropical Pacific to continue, and for La Niña to develop during summer 2003.

“If La Niña develops as expected this would have an impact on the eastern Pacific hurricane season,” said Jim Laver, director for the NOAA Climate Prediction Center. “Typically La Niña has the opposite effect on the eastern Pacific hurricane season than it does on the Atlantic hurricane season.”

“La Niña tends to suppress Pacific hurricane development in contrast to increasing Atlantic hurricane activity,” said Muthuvel Chelliah of the NOAA Climate Prediction Center. “The expected activity is based on a 70 percent likelihood La Niña conditions will develop during the next few months, combined with the overall reduced hurricane activity observed since 1995.”

This is the first year NOAA has issued an experimental outlook for the tropical Eastern Pacific region. This outlook covers the tropical North Pacific east of 140oW latitude. Unlike the Atlantic Hurricane season outlook, NOAA does not plan an August update for this outlook.

Laver added, “NOAA’s Eastern Pacific Hurricane Outlook is important to people in the Southwest and parts of Mexico because a suppressed eastern Pacific hurricane season reduces the likelihood of rain from these systems, especially in Baja California, Arizona, California and New Mexico.” Parts of these areas are already suffering from a multi-year drought, and reduced potential for tropical rainfall events reduces the chances of relief.

The eastern Pacific hurricane season officially begins on May 15 and ends on Nov. 30. The peak of the season runs from July 1 through Sept. 30.

NOAA’s experimental hurricane outlook for the eastern Pacific region is expected to become official beginning with the 2005 season.

The Eastern Pacific Hurricane Outlook is a product of NOAA Climate Prediction Center (CPC), NOAA’s Hurricane Research Division (HRD) and the NOAA National Hurricane Center (NHC).

The Commerce Department’s, National Oceanic and Atmospheric Administration (NOAA), is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of our nation’s coastal and marine resources.

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