Discussion: Australia Bureau of Meteorology ended La Nina 2020-21 today. SSTA in the equatorial East Pacific remains marginally cool (Fig. 1) however upper ocean heat to support La Nina’s survival is disappearing fast (Fig. 2). The Australia Bureau of Meteorology ENSO forecast indicates neutral ENSO ahead for the middle third of 2021 (Fig. 3).
As previously indicated by Climate Impact Company, the strength of the 2020-21 La Nina was reasonably impressive and there is some precedent for La Nina to return later in the year that followed. So…La Nina’s return late this year is possible but the risk is reduced.
More important to northern hemisphere climate prediction is the vast warmth forecast by ECMWF of the middle latitude oceans (Fig. 4). The warm mid-latitude SSTA pattern causes probability forecasts (from the International Research Institute for Climate and Society) for summer temperature to broadly promote widespread anomalous warm risk (Fig. 5).
Neutral ENSO will continue to support an above normal number of tropical cyclones in the North Atlantic basin this year.
Fig. 1: Last week’s Pacific Ocean basin SSTA observations reveal marginally cool waters east of the Dateline in the equatorial Pacific.
Fig. 2: The fast fade of upper ocean heat in the equatorial Pacific east of the Dateline asserts La Nina 2020-21 demise.
Fig. 3: Australia Bureau of Meteorology ENSO forecast for 2021.
Fig. 4: ECMWF global SSTA forecast for JUN/JUL/AUG 2021 identifies the vast warmth of the northern hemisphere oceans.
Fig. 5: The warm summertime oceans across the Northern Hemisphere are linked to very warm probability forecasts for land masses indicated by the International Research Institute for Climate and Society.