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Island Climate Update 259 - April 2022

The NINO3.4 Index anomaly over the last month (to 3 April) was -0.79˚C, near the La Niña threshold. The March monthly Southern Oscillation Index (SOI) was +1.4, in the La Niña range.

Upper-oceanic heat content decreased in the western and central Pacific during March, temporarily halting the transition toward ENSO neutral. The eastern Pacific had slightly above normal oceanic heat content. The overall signature was reflective of a central Pacific La Niña.

In the subsurface equatorial Pacific, the warm pool that was present during February surfaced in the east during March. Cooler subsurface waters redeveloped in central and western areas, which will allow a La Niña-like SST pattern to persist for at least part of the upcoming three months.

La Niña conditions are forecast to continue during April-June (65% chance). Between July- September, there is a 50% chance for ENSO neutral conditions. During October-December, ENSO neutral and La Niña are about equally likely.

Tropical Cyclone Fili, the 7th tropical cyclone of the Southwest Pacific tropical cyclone season, will pass west of New Caledonia on Thursday. There is some risk for additional cyclone development during the month, particularly in the western part of the basin near Vanuatu, New Caledonia, and between the Coral Sea and Queensland.