NOAA/CPC announced yesterday (Oct. 14) that La Nina onset developed in October 2021. The surface/subsurface cool anomalies in the equatorial East Pacific suggest La Nina Modoki. The projected ENSO West-East index (WEI) for October suggests La Nina Modoki. The La Nina episode is forecast to last into early northern hemisphere spring 2022.

Record warm SSTA in the South Atlantic tropics is the catalyst for a wet climate which defeats Brazilian drought into the summer 2021-22 season. The wet pattern is compensated for by a dry climate in Southeast Brazil to northeast Argentina where drought develops. Meanwhile regenerating La Nina brings a wet climate to Australia.

The Climate Impact Company constructed analog ENSO phase forecast using Nino34 SSTA reveals a short-term evolution of La Nina followed by mostly neutral ENSO by next March lasting into mid-2023.

The sunspot number for early October is around 50 which is well above the projected value based on the Sep. 10, 2021 forecast by NASA. In fact, the observation is above the 95th percentile forecast. Conservative forecasts for solar cycle 25 project a similar sunspot number at solar maxima in 2024-25 to the past solar peak occurring twice in 2011-12 and 2013-14. However, based on early trends, solar maximum for 2024-25 could be much stronger.