Fig. 1: The Nino SSTA regions for the past 12 weeks. The Nino12 region off the northwest coast of South America is much cooler.
Discussion: Last week, the Nino 12 SSTA region cooled to -1.7C which ties a week last December for the coolest signature of La Nina 2021-22 (Fig. 1). Indicated is trade winds are increasing and up-welling cold subsurface water off the northwest coast of South America. Not a sign of La Nina weakening. Other Nino SSTA regions are steady in marginal La Nina so far during February. In the subsurface, the Kelvin Wave moving into the equatorial East Pacific in recent weeks are weakening (Fig. 2). Subsurface cooling off the northwest coast of South America cooled last week. A new Kelvin Wave is organizing in the subsurface equatorial West Pacific. The southern oscillation index (SOI) is projected slightly less than +1.0 for February which remains a moderate La Nina signature (Fig. 3).
Fig. 2: The subsurface equatorial Pacific Ocean temperature anomalies.
Fig. 3: The monthly southern oscillation index since January 2020.