La Nina Modoki Risk Later This Year

Highlights: La Nina Modoki Climate Possible by Q4 of 2021.

Discussion: More confident is a return of La Nina by quarter 4 of 2021 by most forecast models. Interestingly, several models are indicating potential for the coolest SSTA associated with the returning La Nina near or just east of the Dateline while waters are near normal off the northwest coast of South America. This condition is representative of a La Nina Modoki and most prominently forecast by NCEP CFS V2 by October (Fig. 1).

If a La Nina Modoki develops for quarter 4 of 2021 the best estimate of the precipitation climate for areas influenced by ENSO is based on the unique analog years of 1983 and 1998 when quarter 4 of each year observed a La Nina condition with the attendant coolest waters biased toward the Dateline.

The North America climate during the La Nina Modoki averaged wetter-than-normal for quarter 4 in the Great Plains and northern California into the Northwest States (Fig. 2). In South America, much-needed rainfall is generated in Brazil (Fig. 3).

Also affected by ENSO is the climate of Australia and Southeast Asia. La Nina Modoki likely prevents drought in Australia and favors wet climate along coastal regions (Fig. 4). In Southeast Asia and Indonesia, the La Nina Modoki favors a wet climate (Fig. 5).

Fig. 1: NCEP CFS V2 global SSTA forecast for October 2021 indicates a possible La Nina Modoki.

Fig. 2: La Nina Modoki North America climatology for quarter 4 of 2021.

Fig. 3: La Nina Modoki South America climatology for quarter 4 of 2021.

Fig. 4: La Nina Modoki Australia climatology for quarter 4 of 2021.

Fig. 5: La Nina Modoki Asia climatology for quarter 4 of 2021.