Island Climate Update 265 - November 2022

The NINO3.4 Index anomaly (in the central equatorial Pacific) over the last month was -0.80˚C (climatology: 1991-2020), in the La Niña range for the third consecutive month.

The NINO3.4 Index anomaly (in the central equatorial Pacific) over the last month was -0.80˚C (climatology: 1991-2020), in the La Niña range for the third consecutive month.

Nov-Jan 2022-23 Island Climate Update

The October monthly SOI was +1.8 and +1.6 from August-October (climatology: 1991-2020), both well within the La Niña range.

Trade winds were much stronger than normal across the central and western equatorial Pacific during October, maintaining a moderate La Niña strength.

In the subsurface central equatorial Pacific, October conditions mirrored those of September. Subsurface anomalies of -3˚C to -5˚C spanned from just below the surface in the east to 150 m depth in the

central. This was juxtaposed by a particularly strong West Pacific warm pool. La Niña conditions are most likely to continue during November-January (85% chance). During February- April, ENSO neutral conditions are most likely (60% chance).

NIWA’s analysis indicates that a moderate La Niña event is ongoing and is expected to last through the first half of summer with an easing possible during late summer and/or autumn. This is the first “triple dip” La Niña (three consecutive La Niña events from 2020-2022) since 1998-2000.

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