Executive summary: ENSO is in moderate La Nina phase now and is forecast to steadily weaken during northern hemisphere meteorological spring. Some characteristics of El Nino (warming in the far eastern equatorial Pacific) are possible mid-year. Forecast confidence is increasing that continuation of La Nina is not likely and neutral ENSO emerges during the middle third of the year. El Nino is possible later this year but forecast confidence is low. Implications of the ENSO forecast for quarter 2 of 2022 are potential developing/strengthening of drought in the Central U.S., East-central China, Southern Europe and Bolivia to Uruguay.
Diagnostics and forecast discussion: Characteristics of the ENSO pattern have suddenly emerged and increase forecast confidence as to where ENSO phase is going for 2022. Up to this point, two schools of thought emerged for ENSO in 2022: 1.) La Nina weakens but continues (NCEP CFS V2) or La Nina weakens and characteristics of El Nino develop (ECMWF and other models). During the past week or so waters off the northwest coast of South America have warmed dramatically (Fig. 1). The warming is due to the arrival of a warm subsurface Kelvin Wave reaching the coast of northwest South America in late FEB/early MAR (Fig. 2). The Kelvin Wave coincided with an eastward-traveling convection phase of the Madden Julian oscillation (Fig. 3), a process common to breaking down La Nina or initiating El Nino. ECMWF correctly forecast the warming off the northwest coast of South America initiating in April (Fig. 4) therefore the warming is a little early. The NCEP CFS V2 failed to predict the warming.
The cool waters of the current La Nina pattern shift westward during the next 2-3 months. The pattern may look like a La Nina Modoki during this process however Climate Impact Company prefers to identify this regime as the decay stage of La Nina. By July, ECMWF indicates the warming strengthens with westward expansion while the cool waters in the equatorial region erode with some remnant cooling near the Dateline (Fig. 5). While an evolving El Nino is implied, forecast confidence for the last third of 2022 is low. The Climate Impact Company constructed analog forecast using multivariate ENSO index (MEI) indicates a trend toward weak El Nino is possible for late in the year (Fig. 6).
Climate implications for quarter 2 of 2022: Given the ECMWF correct projection of warming off the northwest coast of South America for quarter 2 of 2022 we can use the model’s attendant temperature and precipitation outlooks to identify potential high impact climate zones. In North America, implications of a weakening La Nina coupled with warming off the northwest coast of South America imply anomalous warm risk for the West and Central U.S. and dryness for the Great Plains.
In Eurasia, Southwest Europe is dry and marginal dryness extends eastward across Southern Europe to the Black Sea Region. Anomalous warmth favors the southern half of Europe. Much of Russia is warmer than normal for APR/MAY although Western Russia cools to near normal in JUN.
In South America, dryness is dominant across Bolivia to Uruguay and vicinity. Australia loses the summertime wet pattern. Eastern China is drier than normal.
Northern hemisphere summertime drought risk is present for the Great Plains, Southern Europe and possibly the Black Sea region plus East China.
Fig. 1: Recently, the ocean surface off the northwest coast of South America (Nino 12 SSTA zone) warmed dramatically.
Fig. 2: Warming in the subsurface equatorial East Pacific associated with the remains of an east-shifting Kelvin Wave reach the northwest coast of South America.
Fig. 3: An eastward propagating pulse of subsurface warm water in the equatorial Pacific associated with the convection phase of the Madden Julian oscillation.
Fig. 4: ECMWF forecasts warming off the northwest coast of South America in April. The warming arrives one month early.
Fig. 5: ECMWF projects warming off the northwest coast of South America expands westward by July while cool La Nina waters erode near the Dateline.
Fig. 6: Climate Impact Company constructed analog forecast for ENSO phase into early 2023.