Island Climate Update 229 - October

Upper-oceanic heat content anomalies continued to decrease in the eastern and east-central equatorial Pacific during September. The core of the warm pool that had been associated with a central Pacific El Niño earlier in the year was located just west of the International Dateline. While this spatial pattern reflects ENSO neutral conditions, the atmosphere may respond to the growing coolness in the eastern equatorial Pacific during the next three to six months, suggesting that central Pacific El Niño-like patterns will be possible.

During September, rainfall patterns across the tropical Pacific were consistent with ENSO neutral conditions. For the first month in some time, below normal rainfall occurred near the International Dateline.

Trade winds were slightly stronger than normal in the tropical Pacific during September. This led to additional cooling of SSTs. During October, stronger than normal trade winds are forecast to develop in the west-central Pacific, which may contribute to additional cooling in the NINO 3 and 4 regions.

According to the consensus from international models, oceanic ENSO-neutral conditions are most likely at 61% chance for the October – December period with El Niño at 35% chance. For the January – March 2020 period, the probability for neutral conditions is 55% with the chance for El Niño increasing to 40%. For the April – June 2020 period, the probability for neutral conditions and El Niño is 56% and 41%, respectively.

Download the full report: Island Climate Update October 2019 [2.28MB PDF]