La Nina is the result of Kelvin waves and other types of waves sloshing back and forth across the Pacific Ocean. La Nina also disrupts weather patterns usually bring drought. In 1988 the drought in the central United States and the Southwest was linked to a La Nina weather pattern. If this prediction is correct, then estuaries will experience a dilution of salinity during the El Nino phase and an increase in salinity during the La Nina which will stress the estuary ecosystems. There is still much uncertainty about how El Nino will affect the weather over the winter.
Computer models are still inaccurate in some accounts and accurate in others.
Forecasters must wait until there are El Nino-type conditions developing in the ocean before warnings are released. El Nino reaches far across the globe because it creates thunderstorms from Indonesia out into the middle of the Pacific. The towering clouds redirect the atmospheric jet streams, shifting the normal track of storms over North and South America. In the tropics El Nino brings droughts while predictions are the Ohio River Valley will experience very dry conditions. The precipitation is expected to be enhanced in parts of Texas and South Florida.