Tracking The Shifting North America High Pressure Late August/Early September
08/13/2026, 10:25 am EDT
Climate Impact Company ENSO Climate Diagnostics
Issued: Friday August 14, 2026
Highlight: The likely abrupt end to El Nino 2026-27 next northern hemisphere spring and possible La Nina to follow.
Discussion: The most recent ECMWF relative Nino34 SSTA index forecast maintains a projection of record-strength El Nino for late 2026 into early 2027 (Fig. 1). The NCEP CFS V2 forecast also projects record setting +3.5 for Nino34 SSTA during late 2026 (Fig. 2). The speed of strengthening El Nino-like multivariate ENSO index (MEI) coupled with potential energy represented by record-strength subsurface upper ocean heat east of the Dateline in the equatorial Pacific Ocean qualifies the record-setting El Nino forecasts. Of additional interest, is the rapid decline in Super El Nino intensity during northern hemisphere spring and shift to a potential moderate strength La Nina middle of 2027. The NCEP CFS V2 forecast extends to April 2027 and (also) projects a rapid descent in El Nino strength. Climate Impact Company year-2 ahead ENSO forecasts utilizing MEI and relative operational Nino34 index (also) suggest at least a 50% chance of La Nina for the second half of 2027 (Fig. 3-4). Historically, there is a see-saw character to ENSO regimes in the equatorial Pacific whereas strong El Nino episodes are followed by strong La Nina events. The dynamic and analog relative Nino34 SSTA forecasts suggest that possibility in 2027. However, will the much warmer oceans of the past 2-3 decades accelerating during the current decade allow that phenomenon to repeat?
Fig. 1: ECMWF Relative Nino34 SSTA index forecast through JUL/AUG 2027.
Fig. 2: NCEP CFS V2 Relative Nino34 SSTA index forecast through APR 2027.
Fig. 3: Climate Impact Company ENSO phase analog forecast utilizing multi-variate ENSO index through 2027.
Fig. 4: Climate Impact Company ENSO phase analog forecast utilizing relative operational Nino index through 2027.