SEA SURFACE TEMPERATURE (SST)
La Niña continued to weaken during March 2012, as below-average SSTs persisted primarily in the central Pacific. All of the Niño indices have warmed considerably during the last two months, and the Niño 4 and Niño 3.4 indices averaged only near -0.5 in March. The oceanic heat content (average temperature in the upper 300m of ocean) anomalies also continued to warm, with alternating pockets of negative and positive temperature anomalies observed within the upper 100 m in the central and eastern Pacific. Significant anomalous low-level westerly winds developed in the western tropical Pacific in late March, associated with the MJO. This wind event could further warm the central and eastern Pacific within the coming few months. Collectively, these oceanic and atmospheric patterns indicate that a transition from La Niña to ENSO-neutral conditions is underway.