Along the equator, trade winds push warm equatorial Pacific water from east to west. That causes stormy weather for Malaysia, the Philippines and Indonesia.
During El Nino, these winds weaken, and the warm water moves toward the Americas to the eastern Pacific, and that provides fuel for stormy conditions for Southern California.
The 1997-98 El Nino claimed 17 lives and caused more than half-billion dollars in damage throughout California. Compared to that El Nino event, this year's El Nino has spread warm waters further north. This is why the Climate Prediction Center is calling this one of the strongest on record.
"This El Nino is larger, it's more intense, it's more deeply embedded in the ocean," said NASA climatologist Bill Patzert, who has spent more than 20 years studying El Nino.
For the Southland, that means a wetter rain season, which has many impacts including possible flooding, mud and landslides. Patzert says more doesn't necessarily translate into catastrophe.
"El Nino's tend to give you smaller storms, but more frequent storms," he said. "That's manageable, if we prepare for it and manage it."
The Climate Prediction Center is reporting a 95 percent chance the El Nino event will continue strongly through the winter.