The Climate Prediction Center issued its report yesterday stating that "There is a 50% chance that El Niño conditions will develop during the second half of 2012." Since La Niña ended in April we are now seeing neutral conditions.
NOAA's National Weather Service and their funded institutions, study both the effects of trade winds and ocean temperatures to see how these oscillations affect the state of our climate.
Where and how does El Niño affect us?
In the Tropics, El Niño episodes are associated with increased rainfall across the east-central and eastern Pacific and with drier than normal conditions over northern Australia, Indonesia and the Philippines. Elsewhere, wetter than normal conditions tend to be observed 1) during December-February (DJF) along coastal Ecuador, northwestern Peru, southern Brazil, central Argentina, and equatorial eastern Africa, and 2) during June-August (JJA) in the intermountain regions of the United States and over central Chile. Drier than normal conditions generally observed over northern South America, Central America and southern Africa during DJF, and over eastern Australia during JJA. El Niño episodes also contribute to large-scale temperature departures throughout the world, with most of the affected regions experiencing abnormally warm conditions during December-February. Some of the most prominent temperature departures include: 1) warmer than normal conditions during December-February across southeastern Asia, southeastern Africa, Japan, southern Alaska and western/central Canada, southeastern Brazil and southeastern Australia; 2) warmer than normal conditions during June-August along the west coast of South America and across southeastern Brazil; and 3) cooler than normal conditions during December-February along the Gulf coast of the United States.
To see the the ocean temperature change over time, visit here; http://climatedriver.blogspot.com/p/sea-surface-temps-el-nino-status.html
As I explained before I have been caught in a tropical storm when I lived in Ecuador in 1998, where I saw intense flooding rains. Here is a video that gives a good visual explanation of El Niño.