>Figure 1 shows weekly NINO3.4 SST anomalies from January 7, 2004 through February 9, 2011. The central equatorial Pacific SST anomalies have risen significantly in the last week.
Figure 2 compares the SST anomalies for the transitions from El Niño to La Niña events, during the years of 1988/89, 1998/99, 2007/08, and 2010 through February 9, 2011. At first glance, it appears this rebound started early, but the rebound from the 1988/89 La Niña actually started rising from its minimum a few weeks earlier.
And since we’re looking at weekly data, Figure 3 shows the Global SST anomalies from January 7, 2004 through February 9, 2011.
The Optimally Interpolated Sea Surface Temperature Data (OISST) are available through the NOAA National Operational Model Archive & Distribution System (NOMADS).