Island Climate Update 218 - November 2018

Sea surface temperatures (SSTs) in the central Pacific (NINO3.4 Index) warmed notably over the past month, increasing from an anomaly of +0.25°C in September to +0.75°C in October.

Sea surface temperatures (SSTs) in the central Pacific (NINO3.4 Index) warmed notably over the past month, increasing from an anomaly of +0.25°C in September to +0.75°C in October. The anomaly value for October exceeded what international centres consider necessary for the onset of El Niño conditions. The NINO1+2 Index in the eastern Pacific (near South America) continued to show significant variability. This pattern of SST anomalies continues to be consistent with the expected development of El Niño ‘Modoki’, a non-conventional type where the maximum SST anomaly is located in the central Pacific rather than the eastern Pacific

November-January 2019 Island Climate Update


Warmer than average subsurface ocean waters strengthened and expanded eastward during October. Anomalies of +3.0°C and above now cover a wide area from the Dateline to 100oW at 150m depth in the west and 50m depth in the east. This is associated with large upper-ocean heat content anomalies (+1.5 to 2.0°C), spanning from near the Dateline to about 110°W.


The Southern Oscillation Index (SOI) was slightly positive with a value of +0.2 for October 2018, following negative values during August and September.


The consensus from international models is for the tropical Pacific to transition towards El Niño over the next three-month period (88% chance over November 2018 – January 2019). The probability for El Niño remains high through autumn 2019, with a 88% chance for El Niño conditions over the March – May 2019 period, with some long-range models indicating the possibility of the event continuing through next winter in the Southern Hemisphere (a protracted El Niño event).

Download the report: Island Climate Update November 2018 [3.27MB PDF]

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