By WMBD TV
(Peoria, Ill.) WMBD — We’re coming off two consecutive La Niña winters and are well on our way to an El Niño as Sea Surface Temperatures (SST) are heating up across the eastern Pacific. Latest model projections are calling for a strong to very strong El Niño, what some are calling a “super El Niño”, by fall and winter. This could potentially be the strongest El Niño since 2015-16 winter season.
The El Niño Southern Oscillation (ENSO)
This is most well known teleconnections and often has a decent influence on seasonal weather forecasts, especially in the winter. It’s not an answer key, but this pattern can be predicted months in advance and and giving us some insight on it’s impacts.
There are three phases to ENSO that are determined by monitoring sea surface temperatures and wind patterns over the equatorial region of the Pacific Ocean. These phases are:
- El Niño (Positive Phase) – This phase occurs when sea surface temperatures across the central and eastern Pacific are above average. This often results in less rainfall over Indonesia and increased rainfall across the central and eastern Pacific. Shifting winds near the equator will carry tropical moisture north into North America. This typically leads to cooler and wetter seasons across the southern U.S. while warmer and drier seasons occur across the northern U.S.
- La Niña (Negative Phase) – In this phase, sea surface temperatures across the central and eastern Pacific are below average and rainfall often increases across Indonesia. The sub-tropical jet stream weakens and polar jet becomes the main driving force for storms across the U.S. and results in dry and warm conditions across the southern U.S. while the northern part of the country sees cooler and wetter seasons.
- Neutral Phase – Sea surface temperatures across the central and eastern Pacific Ocean are near average and there for “neutral”. In this phase, the ability to make an accurate prediction becomes much more difficult since the driving factors become muted.
The part of the Pacific Ocean we’re most interested when monitoring ENSO is an area known as Nino 3.4 (Figure 1). As of May 11th, SST anomalies in this region were just around + 0.6° C (Figure 2) which is warm enough to be considered an El Niño, well sort of. We need to have SST anomalies remain at or above 0.5° C for three consecutive months before we can say El Niño is officially underway. That should happen by mid to late July.
ENSO forecast through winter 2026
The latest ENSO probability forecast (Figure 3) show that neutral conditions are favored through June with El Niño conditions becoming likely by the end of the May, June, & July (MJJ) period. These conditions should remain in place through the 2026-27 winter and will likely persist into Spring. Forecast model plumes suggest the ENSO index could reach strong (>1.5° C) to very strong (>2.0° C) by fall. This doesn’t necessarily mean that the corresponding impacts will be amplified, just that they’ll be more likely.
El Niño impacts on central Illinois
El Niño events are highly variable from one event to the next and there are other factors that ultimately influence the weather. That said, we can still look at similar scenarios in the past and find some trends between the events.
Here is a summary of the impacts of El Niño on Illinois according to the Illinois State climatologist:
- Summers tend to be slightly cooler and wetter than average
- Autumns tend to be wetter and cooler than average
- Winters tend to be warmer and drier with below average snowfall
- Warmer winters = lower heating bills
- Springs tend to be drier than average
I went back and looked at the average temperature and precipitation anomalies of all the strong to very strong El Niño events from the past. These maps show the trends the Illinois State Climatologist mentioned above, though the precipitation stats tend to be more variable from year-to-year.
So if this upcoming summer were to follow the historical trends seen with past El Niño events, we can expect a slightly cooler summer with above average precipitation. El Niño will be in full force by the start of the 2026-27 winter which suggest a warmer and drier winter could be instore for central Illinois.
WMBD TV was first to report on this story. You can read the original story online at CIProud.com.
