Monday, March 14, 2011
La Nina weakened, likely to be gone before Summer
According to the most recent NOAA's weekly ENSO report, the NINO 3.4 index weakened from -1.3 or so a week ago (and from -1.8 in the early October 2010) to -1.0.
In fact, the NOAA folks think that the ongoing La Nina episode will end and ENSO-neutral conditions will return by June 2011. That should still be enough for the ENSO cycle to negatively contribute to the global mean temperature throughout 2011, making it one of the cooler years.
However, you can't be certain that the La Nina episode will end. The average of the models simulations just mildly crosses above the -0.5 °C threshold that defines the conditions. Some models remain below this threshold, in the La Nina territory, and you don't want to trust the models as such too much, anyway: 3 months is a pretty long time for similar predictions, as can be seen by the wild differences between the individual models' predictions.