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ENSO Tracker - Dec 2021 | CLIMAS

 SW Climate Outlook

ENSO Tracker - Dec 2021

ENSO Tracker

Sea surface temperature (SST) forecasts for Jan – Mar 2022 indicate cool conditions across the equatorial Pacific (Fig. 1). Current Nino 3.4/4 anomalies have reached the La Niña threshold (Fig. 2), and most ENSO outlooks now call for La Niña conditions to last through winter 2021-2022.

Forecast Roundup: On Dec 7 the Australian Bureau of Meteorology ENSO outlook was at La Niña status, noting “Sea surface temperatures in the tropical Pacific have cooled to La Niña thresholds, with climate model outlooks expecting them to cool further”, and highlighting the presence of oceanic/atmospheric coupling. On Dec 9 the NOAA Climate Prediction Center (CPC) maintained their “La Niña Advisory” noting strengthening La Nina conditions, and calling for a 95-percent chance of La Niña during winter 2021-2022. On Dec 9 the International Research Institute (IRI) issued an ENSO Quick Look (Fig. 3), noting “A large majority of the models predict SSTs to cool further or stay below-normal during boreal winter, and then return to ENSO-neutral levels during spring.” On Dec 10 the Japanese Meteorological Agency (JMA) observed La Niña conditions are present and called for a 60-percent chance of La Niña conditions to last through winter and an 80-percent chance they would “dissipate” by the end spring. The North American Multi-Model Ensemble (solid and dashed black line, Fig. 4) reached La Niña levels, and indicates a further swing to moderate La Niña in late 2021 and into 2022.

Summary: The seasonal outlooks have reached consensus on a La Niña event in winter 2021-2022. This is tied to cooling SSTs in the equatorial region, and oceanic/atmospheric coupling indicative of La Niña. The event is expected to last through winter and into spring 2022. La Niña winters are frequently warmer and drier than average in the Southwest, so the prospects of an improvement in drought conditions and the cumulative precipitation deficits are slim (but not none).

Online Resources

  • Figure 1 - Australian Bureau of Meteorology -
  • Figure 2 - NOAA - Climate Prediction Center -
  • Figure 3 - International Research Institute for Climate and Society -
  • Figure 4 - NOAA - Climate Prediction Center -