Island Climate Update 232 - January 2020

El Nino –Southern Oscillation (ENSO) neutral conditions continued during December 2019. Both the Southern Oscillation Index (SOI) and sea surface temperatures (SSTs) remained on the El Niño side of neutral but weakened compared to previous months.

The NINO3.4 Index anomaly (in the central Pacific) for the month of December cooled to +0.41 ̊C compared to +0.64 ̊C the month before. The warmest surface ocean waters along the equatorial Pacific were still found in the western Pacific, with the NINO4 region (west-central Pacific) posting a monthly value of +0.84 ̊C. The SOI value for December 2019 is -0.6 (on the El Niño side of neutral).

During December 2019, upper-oceanic heat content remained above average in the equatorial Pacific and spread eastward. Anomalies exceeding +0.5 ̊C were present from 160 ̊E across the Dateline to ~ 140 ̊W.Rainfall was well below normal about the eastern Indian Ocean, Indonesia, and northern Australia while it was above normal across parts of the western Indian Ocean. In the tropical Pacific, rainfall was above normal just west of the International Dateline, and below normal east of it, a pattern which was El Niño Modoki-like.

According to the consensus from international models, ENSO-neutral conditions are most likely (~53% chance) for the January–March period. For the April–June 2020 period, the probability for ENSO-neutral conditions increases to 68% and then decreases to 50% for the July –September 2020 period. In summary ENSO-neutral remains the most likely outcome until the end of winter 2020.

Download the full report: Island Climate Update - January 2020