Lengthy 2020-22 La Nina May Stick-around in 2022

Fig. 1: Multivariate ENSO index analog years pushed forward through 2022 and into early 2023. La Nina weakens the first half of 2022 but neutral ENSO or weak La Nina has a 2-in-3 chance of continuing while El Nino risk is 1-in-3.

Discussion: Multivariate ENSO Index (MEI) is the atmospheric response to the equatorial SSTA pattern of the Pacific Ocean. Interestingly, MEI (and other traditional ENSO indices) initiated La Nina during MAY/JUN 2020. However, unlike the Nino34 Index which ended La Nina temporarily in 2021, MEI maintained a moderate intensity La Nina atmosphere. The 2020-22 “double La Nina” is similar in time scale to the 2007-09 and 2010-12 episodes while 1998-00 was similar in length but of greater amplitude (Fig. 1). The analogs indicate that La Nina is certain to weaken heading toward middle of 2022, become neutral in July and then remain neutral for the remainder of the year, shift back to weak La Nina or roar into El Nino for the last third of the year.

Dynamic and statistical model ENSO projections through the remainder of 2022 reveal neutral ENSO ahead by MAR/APR/MAY lasting the remainder of the year using the Nino34 index (Fig. 2).

The Australia Bureau of Meteorology ENSO forecast reveals a steady collapse of La Nina through quarter 1 and into quarter 2 of 222 (Fig. 3). The rate of warming of the equatorial East Pacific suggests El Nino might develop later this year.

The NCEP CFS V2 model has recently trended toward a slower demise of La Nina (Fig. 4). The model suggests that a weak La Nina may linger through much of 2022.

Fig. 2: A collection of ENSO forecasts using both dynamic and statistical models by the International Research Institute for Climate and Society.

Fig. 3: The latest ENSO phase forecast using the Nino34 Index by the Australia Bureau of Meteorology.

Fig. 4: The latest ENSO phase forecast using the Nino34 Index by the NCEP CFS V2 model.