Current Situation and Outlook
The tropical Pacific atmosphere and ocean are currently at moderate El Niño levels. The majority of international El-Niño Southern Oscillation (ENSO) climate models suggest that tropical Pacific temperatures are likely to continue warming, and possibly reach strong El Niño levels, in the coming months. However, model outlooks made at this time are not as accurate as those made during the second half of the year, and hence more confident estimates of event strength will be available after mid-year. National Meteorological and Hydrological Services and other agencies will continue to monitor the conditions over the tropical Pacific for further El Niño development and will assess the most likely local impacts.
As of late May, east-central tropical Pacific Ocean surface temperatures have ranged between +1.0° and +1.5° Celsius above average, indicating that the current El Niño is now at moderate strength. While sea surface temperatures in the tropical Pacific Ocean reached El Niño levels during late 2014, many of the atmospheric features of El Niño did not become significant until early 2015. The atmospheric indicators of El Niño have become more consistent during recent months with the 90-day Southern Oscillation Index near -1.0, indicating a coupling between the atmosphere and oceans with the event now maturing. For example, the typical El Niño pattern of cloudiness and rainfall in the vicinity of the dateline has become apparent, as has a weakening of the trade winds from the western to east-central Pacific. The cloudiness and rainfall indicator is important because it is considered essential in triggering El Niño’s global climate impacts. Historically, a mature El Niño event is less likely to dissipate rapidly, and is likely to persist until early the following year.