The Super Atlantic Niño of 2021

In 2021 there was an exceptionally strong Atlantic Niño—stronger than the last major event in 1996. Positive SST anomalies developed in May and peaked in June-August. There was a build up of heat content in the spring in the western north Atlantic that could be related to local wind stress curl anomalies.  The event appears to have been triggered by zonal wind anomalies in April and May in the western equatorial Atlantic, when strong rainfall anomalies were also observed along the equator. The event terminated with rainfall anomalies shifting northward in late summer. Interestingly, there was also a strong Benguela Niño that developed already in April and has persisted into boreal summer. Furthermore, the event may have contributed to the La Niña event that developed later in the year in the Pacific.