Over the last month or so warm sea - surface temperature [SST] and upper - ocean heat content anomalies have increased in the near - equatorial central Pacific, while
the SST cool tongue in the near - equatorial far - eastern Pacific has weakened, with warm anomalies now evident there.
If there is no contribution of
cool SST's to that area, then the warm
tongue will move farther east and change the vertical structure of the atmosphere creating a greater liklihood of El Nino.