Synopsis: A transition to ENSO-neutral is likely during late Southern Hemisphere autumn or early winter 2016, with close to a 50 percent chance for La Niña conditions to develop by the spring.
Sea surface temperature (SST) anomalies decreased across most of the central and eastern equatorial Pacific Ocean during February. The latest Niño-3.4 and Niño-3 weekly values were near 2°C, while the Niño-4 and Niño-1+2 indices were 1°C and 1.4°C respectively. The subsurface temperature anomalies in the central and eastern Pacific decreased substantially in association with the eastward shift of below-average temperatures at depth. Low-level westerly wind anomalies and upper-level easterly wind anomalies continued, but were weaker relative to January. The traditional and equatorial Southern Oscillation Index (SOI) remained strongly negative. In addition, convection was much enhanced over the central and east-central tropical Pacific and suppressed over parts of Indonesia and northern Australia. Collectively, these anomalies reflect the continuation of a strong El Niño.
All models indicate that El Niño will weaken, with a transition to ENSO-neutral likely during the late autumn or early winter 2016. Thereafter, the chance of La Niña conditions increases into the spring. While there is both model and physical support for La Niña following a strong El Niño, considerable uncertainty remains. A transition to ENSO-neutral is likely during late Southern Hemisphere autumn or early winter 2016, with close to a 50 percent chance for La Niña conditions to develop by the spring.
Almost all of the North Island should be slightly to moderately above normal.
Near normal across nearly the entire island slightly drier in the east from Northland through to East Cape and Hawkes Bay.
Almost all of the South Island should be slightly to moderately above normal.
Near normal everywhere except slightly to moderately wetter down the east coast.