Island Climate Update 214 - July 2018

El Niño –Southern Oscillation (ENSO) neutral conditions continued across the tropical Pacific during June 2018. Sea surface temperatures (SSTs) in the central equatorial Pacific warmed for the third consecutive month and are currently slightly above average. The NINO3.4 is currently weakly positive with a value of + 0.27°C for June 2018.

 In the subsurface ocean, (within the first 150 metres of the ocean) positive temperature anomalies extend from the western Pacific (near 160°E) to the South American coast. Significant positive anomalies (> +3.0°C) have migrated from the central Pacific during May to the eastern Pacific during June at 50-100m depth. Positive anomalies of +2.0°C extend to 25m depth from about 130°W to the coast of South America and appear poised to surface in the basin over the upcoming months.

The Southern Oscillation Index(SOI) was slightly negative with a value of -0.5 for June 2018, but remains in the neutral range. The Intertropical Convergence Zone remained north of its climatological position in the central Pacific and the South Pacific Convergence Zone was south of its climatological position.

Warming temperatures across the subsurface and surface waters in the equatorial Pacific, weaker than normal trade winds, and convective anomalies broadly indicative of El Niño may indicate the trend of the climate system for spring 2018. In the meantime,  the consensus from international models is for the tropical Pacific to persist in an ENSO-neutral state over the next three-month period (52% chance over July –September 2018). However, El Niño conditions become favored in the following three-month period (54% chance over August–October 2018), peaking in December 2018 –February 2019 at a 71% chance.

Download the report: Island Climate Update July 2018 [1MB PDF]