El Niño, nature's chaotic climate agent, has formed in a warmed-up Pacific Ocean and is expected to grow to historic strength, meteorologists said Thursday.

U.S. meteorologists say an El Nino has formed. That's the natural warming of parts of the Pacific that changes weather around the globe.

El Niño has officially begun, and it is forecast to intensify into a very strong or “Super” El Niño with major shifts in global weather patterns.