El Niño Update: Chances for weak to moderate El Niño move higher

There is an approximately 65% chance that El Niño conditions will be present during the Northern Hemisphere winter and last into the Northern Hemisphere spring 2015, NOAA\'s latest El Niño climate predictions show. This is up from 58% predicted in the November report. Australian authorities say there is at least a 70% chance that El Niño will be declared in the coming months.

December 11, 2014

Similar to last month, most models predict sea surface temperature anomalies to be at weak El Niño levels during November-January 2014-15 and to continue above the El Niño threshold into early 2015 (Fig. 6). Assuming that El Niño fully emerges, the forecaster consensus favors a weak event. In summary, there is an approximately 65% chance of El Niño conditions during the Northern Hemisphere winter, which are expected to last into the Northern Hemisphere spring 2015 (click CPC/IRI consensus forecast for the chance of each outcome).

Meanwhile, the Australian Bureau of Meteorology said many climate indicators remain close to El Niño thresholds, with climate model outlooks suggesting further intensification of conditions remains likely. The Bureau’s ENSO Tracker status is currently at ALERT, indicating at least a 70% chance that El Niño will be declared in the coming months. Whether or not an El Niño fully develops, a number of El Niño-like impacts have already emerged.

Several ENSO indicators are currently close to, or exceed, El Niño thresholds. These include tropical Pacific Ocean temperatures, which have now exceeded El Niño levels for a month, and the Southern Oscillation Index, which has remained at or near El Niño levels for three months. Other indicators, such as tropical cloud, trade winds and rainfall patterns, have either remained near average or only temporarily approached thresholds. This indicates a typical El Niño ocean–atmosphere interaction may not be fully locked in.

The majority of international climate models surveyed by the Bureau suggest further warming of the tropical Pacific Ocean is likely, so it also remains possible that the ocean and atmosphere will fully couple in the coming weeks to months. If an El Niño is established, models suggest it will be weak, or moderate at most. Some El Niño-like impacts have already been seen this spring in Australia and several regions around the globe, including Asia, South America and southern Africa.