EL NINO u u El Nino, an abnormal warming of surface ocean waters in the eastern tropical Pacific, is one part of what's called the Southern Oscillation.

NORMAL YEAR u u In a normal year, the trade winds blow westward and push warm surface water near Australia and New Guinea.

NORMAL YEAR u u When warm water builds up in the western Pacific Ocean, nutrient-rich cold water comes up off the west coast of South America & fosters the growth of the fish population.

EL NINO YEAR During an El Niño year, the trade winds weaken & warm, nutrient-poor water occupies the entire tropical Pacific Ocean.

EL NINO YEAR Heavy rains that are tied to the warm water move into the central Pacific Ocean and cause drought in Indonesia and Australia.

u u Normal Year u EL NINO Year

EL NINO u u The Southern Oscillation is the see-saw pattern of reversing surface air pressure between the eastern and western tropical Pacific. u u When the surface pressure is high in the eastern tropical Pacific it is low in the western tropical Pacific, and vice- versa.

EL NINO u u Because the ocean warming and pressure reversals are, for the most part, simultaneous, scientists call this phenomenon the El Nino/Southern Oscillation. u u South American fisherman have given this phenomenon the name El Nino, which is Spanish for "The Christ Child," because it comes about the time of the celebration of the birth of the Christ Child at Christmas.

EL NINO u u Scientists do not fully understand how El Nino forms. u u It is believed that El Nino may have contributed to the 1993 Mississippi and 1995 California floods, drought conditions in South America, Africa and Australia.

EL NINO u u It is also believed that El Nino contributed to the lack of serious storms such as hurricanes in the North Atlantic which spared states like Florida from serious storm related damage. u u The goal is to provide sufficient warning so that we can be better prepared to deal with the damages and changes that El Nino causes in the weather.