ENSO Tracker - June 2021

ENSO Tracker - June 2021

Sea surface temperature (SST) forecasts for July – Sept 2021 call for cooling conditions across the equatorial Pacific (Fig. 1). The current Nino 3.4/4 anomalies have returned to the range of neutral (Fig. 2). The ENSO outlooks note the persistence of neutral conditions in the short term, along with the potential return of La Niña conditions in winter 2021-2022.

Forecast Roundup: On June 10, the NOAA Climate Prediction Center (CPC) ENSO status was “not active”, and they called for an 78-percent chance of ENSO-neutral during June-August 2021. On June 10, the Japanese Meteorological Agency (JMA) observed that ”the La Niña that started in summer 2020 has terminated”, with a 60-percent chance of neutral conditions continuing to autumn. On June 18, the International Research Institute (IRI) issued an ENSO Quick Look (Fig. 3), noting “A large majority of the model forecasts predict SSTs to remain near-normal through boreal summer.” On Jun 22, the Australian Bureau of Meteorology ENSO tracker was neutral/inactive, stating ENSO “remains neutral with all oceanic and atmospheric indicators within the neutral range.” The North American Multi-Model Ensemble (solid and dashed black line, Fig. 4) are back to ENSO-neutral, and are expected to remain neutral through summer, but show the potential for another round of La Niña in 2021-2022.

Summary: La Niña conditions are over and ENSO neutral conditions have returned. Most seasonal forecasts are bullish neutral conditions will remain through summer. Longer-term forecasts hint at a return of La Niña in winter 2021/2022, despite considerable uncertainty in these forecasts. The picture should be clearer by the end of summer, but if La Niña returns, this does not bode well for accumulated drought, particularly if the Southwest experiences another below normal monsoon.

Online Resources

  • Figure 1 - Australian Bureau of Meteorology - bom.gov.au/climate/enso
  • Figure 2 - NOAA - Climate Prediction Center - cpc.ncep.noaa.gov
  • Figure 3 - International Research Institute for Climate and Society - iri.columbia.edu
  • Figure 4 - NOAA - Climate Prediction Center - cpc.ncep.noaa.gov