*EPF423 05/09/2002
Text: NOAA Predicts Weak to Moderate El Nino Conditions
(Global impact expected to be much weaker than 1997-98 event) (540)

Scientists of the National Oceanic and Atmospheric Administration (NOAA) predict that "weak to moderate" El Nino weather conditions will develop by the end of 2002.

According to a May 9 press release, scientists at NOAA's Climate Prediction Center said that warmer-than-normal sea surface and subsurface temperatures were observed throughout most of the equatorial Pacific during April. Sea surface temperatures were up to 2 degrees Celsius warmer than average in the region between the Galapagos Islands and the South American coast.

NOAA noted that a weak to moderate El Nino would feature less significant global impacts than were experienced during the very strong 1997-98 El Nino.

During a major El Nino, the normally cold water off the west coast of South America becomes much warmer, exceeding normal temperatures by several degrees, while the waters in the western Pacific cool.

El Ninos can affect weather conditions around the world. Among the consequences, for example, are increased rainstorms across the southern tier of the United States and in Peru, which have caused destructive flooding; and drought in the West Pacific, sometimes associated with devastating brush fires in Australia.

Further information is available at the following Web site: http://www.cpc.ncep.noaa.gov/

Following is the text of the press release:

(begin text)

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION (NOAA)

Climate Prediction Center (CPC)

May 9, 2002

EL NI��/SOUTHERN OSCILLATION (ENSO)

Warmer-than-normal sea surface and subsurface temperatures were observed throughout most of the equatorial Pacific during April 2002. Sea surface temperature anomalies were up to 2�� warmer than average in the region between the Galapagos Islands and the South American coast, and greater than 1�� warmer than average immediately to the west of 180��.

Although there was considerable warming in the eastern equatorial Pacific during February-April, which resulted in locally heavy rainfall along the coasts of Ecuador and northern Peru, there was little change in subsurface temperature anomalies in regions farther west during this period. Consistent with this lack of evolution in the central equatorial Pacific, atmospheric indices for low-level winds, sea level pressure and precipitation continue to indicate near-normal conditions.

The Madden-Julian Oscillation (MJO) is an important source of variability that can contribute to a more rapid evolution toward El Ni�� through related fluctuations in low-level winds and precipitation over the western and central equatorial Pacific. An eastward-propagating oceanic Kelvin wave, initiated by strong MJO activity in late 2001, resulted in the rapid warming that was observed along the coasts of Ecuador and northern Peru in early February. Since that time, MJO activity has weakened and there has been no additional significant Kelvin wave activity. Without such activity a slow evolution towards El Ni�� conditions is possible through the remainder of 2002.

This assessment agrees well with several coupled model and statistical forecasts, which indicate a gradual warming over the next several months with weak-to-moderate El Ni�� conditions by the end of 2002. It is important to add that a weak or moderate El Ni�� would feature considerably weaker global impacts than were experienced during the very strong 1997-98 El Ni��.

(end text)

(Distributed by the Office of International Information Programs, U.S. Department of State. Web site: http://usinfo.state.gov)

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