Island Climate Update 265 - October 2022

The NINO3.4 Index anomaly (in the central equatorial Pacific) over the last month (through 30 September) was -0.93˚C (climatology: 1991-2020). In the last four decades, only four Septembers hadcooler central equatorial Pacific SSTs than 2022, including September 2010, 1999, 1998, and 1988.

The September monthly SOI was +1.4 and +1.7 from July-September (climatology: 1991-2020), both wellthe La Niña range.

Trade winds were stronger than normal across the central equatorial Pacific and off-equatorial South Pacific during September. This helped to maintain the moderate La Niña.

In the subsurface central equatorial Pacific, cold anomalies intensified during September, particularly east of the Date Line. The thermocline was located near the surface in eastern part of the basin, consistent with La Niña conditions. Sub-surface anomalies of -3˚C to -5˚C are expected to continue to push toward the surface, likely resulting in further cooling of the ocean surface and additional strengthening of La Niña.

La Niña conditions are most likely to continue during October-December (80-85% chance), an increase of about 10% compared to last month. During January- March, La Niña and ENSO neutral are about equally likely (45-50% chance). This “triple dip” (3rd consecutive) La Niña will affect rainfall, temperatures (air and sea), sea level, and tropical cyclone activity in the Southwest Pacific in thecoming months. The tropical cyclone outlook will be released during mid-October.

Download

• Island Climate Update - October 2022 [PDF 5.87 MB]