The Center added on its web site http://www.cpc.ncep.noaa.gov/products/analysismonitoring/ensoad v isory/index.html "El Nino conditions are expected to develop during the next three months,"

There is about "a 50 percent chance that the NOAA operational definition for El Nino will be satisfied for the period June-August 2004," the Center predicted.

"Approximately half of the statistical and coupled model forecasts indicate near neutral conditions in the tropical Pacific through the end of 2004. The remaining forecasts indicate El Niño conditions will develop within the next 3-6 months," it added.

A Kelvin wave which is pushing the warm waters eastward has been observed, contributing to "an increase in the subsurface temperature anomalies in the central and east-central equatorial Pacific (Ocean). This Kelvin wave is expected to reach the South American coast during August," the Center said.

El Nino is a weather phenomenon which leads to an abnormal warming of waters in the equatorial Pacific Ocean, recurring roughly once every three years.

The anomaly was first noticed by Latin American anchovy fishermen in the 19th century and was named in honor of the Christ child because it would take place around the year-end Christmas holiday season.

Severe El Ninos, as happened in 1997/98, would cause searing drought in Australia, the Philippines and Indonesia while spawning rampant flooding in Chile, Ecuador and Bolivia. Another Nino in 2002/03 caused the worst drought in Australia in a century.

The warming of Pacific Ocean waters can cause floods and drought as far as South Africa and trigger severe winter storms in California.

El Nino killed hundreds of people in 1997/98 and caused billions of dollars in damages. Before that, another El Nino in 1977/78 likewise killed hundreds and caused several hundred million dollars in damages.