If El Nino Appears Later 2023, How Will Global Precipitation Patterns Change?

Executive summary: La Nina 2020-22 is likely to produce a 3^rd peak in November followed by a steady demise in early 2023 (Fig. 1). Most analog and dynamic model forecasts agree with this scenario. Neutral ENSO evolves by FEB/MAR 2023 and El Nino may follow for the second half of 2023. If El Nino generates later in 2023, a much different climate pattern emerges. Included wet risk for the Southern U.S. and northern Argentina/southern Brazil and a dry climate for India, Southeast Asia, Indonesia, and Australia (Fig. 2).

Fig. 1: Historical review of La Nina 2020-22 and using an analog, the projected most likely phase of ENSO for 2023.  

Fig. 2: Wet/dry climate zoned for SEP-DEC 2023 if an El Nino climate generates.

Discussion: Madden Julian oscillation (MJO) is forecast to strengthen across the far western equatorial Pacific over the next 2 weeks. The MJO episode will take advantage of the warmer than normal surface and subsurface water in that region causing an increase in tropical convection. To replace the rising air currents in the equatorial far West Pacific, trade winds to the east increase and up-welling cool waters near and east of the Dateline also increase. Consequently, a 3^rd peak in La Nina strength is forecast for November 2022 (Fig. 3).

However, forecast models are indicating the dynamic described above ends by next February (Fig. 4) as the far west equatorial Pacific Ocean cools to near normal, trade winds are discouraged and up-welling of cool subsurface water to sustain La Nina fades.

Once trade winds fade, extremely warm waters near and west of the Dateline (Fig. 5) at the surface and subsurface will likely shift eastward. If another MJO event occurs, which is likely, a Kelvin Wave of warm water organizes near the Dateline and surges eastward (Fig. 6) to end any remnants of La Nina.

The NCEP CFS V2 (model) indicates a similar Nino34 SSTA forecast (Fig. 7) to the analog projection by Climate Impact Company.

Fig. 3: The IMME global SSTA forecast for November 2022.

Fig. 4: The IMME global SSTA forecast for February 2023.

Fig. 5-6: Subsurface equatorial Pacific Ocean upper heat analysis and zones of concern to monitor La Nina.

Fig. 7: Latest NCEP CFS V2 Nino34 SSTA forecast valid through middle of 2023.