If you look at that image above, you can see these anomalies of below normal water temperatures are shaped like the letter C, or for you avid weather folk, backwards bow echoes. These wave-like formations assure that this is not simply a random cooling, but that this is a phenomenon, to which we name it the ENSO. In cooler than normal waters from the northwest coast of South America across the Equatorial Pacific, warmer than normal waters indicate an El Nino and cooler than normal waters show a La Nina.
The ENSO phenomenon is commonly named as the driver behind winter weather conditions in North America. In a La Nina pattern, stormy conditions overtake the Ohio Valley and interior Northeast, with cold weather prevalent across the North Plains. Warmth is then present across parts of the South and West US, mostly in the South. The La Nina is what provoked the still-ongoing 2011 Drought that ravaged Texas and several other states.
It should be noted that there is a warm body of water about 100-200 meters below the surface that could hamper the development of this La Nina. I will address that when the time comes.