Speak directly into someone’s ear and you’re likely to be understood. Shout it across a busy intersection, and you lose a lot of clarity.
Meteorologists have a similar problem explaining 2026’s “Super El Niño.” The cyclical heat bulge in the Pacific Ocean has predictably raised tides and temperatures along the California coast this fall. But as that weather energy moves inland, forecasters’ crystal balls become, well, cloudy.
“There’s a lack of certainty around the predictions,” Montana State Climatologist Kelsey Jencso told Mountain Journal. “The odds are leaning toward a warmer-than-normal winter, but precipitation estimates are highly uncertain. For a lot of Montana, there’s not a statistical bearing on those results.”
El Niño — “Little Boy” in Spanish — refers to part of a multi-year climatic cycle where a concentration of warmer-than-usual ocean water west of South America triggers changes in global wind and ocean current patterns. In turn, that scrambles seasonal weather systems. For example, parts of Ecuador have been drenched with 20 inches of rain this October, compared to the typical 0.2 inches for the month. Offshore ocean temperatures are running almost 17 degrees F above average. California coastlines are already seeing sea levels a foot above normal, leading to big waves and rainfall-driven erosion damaging highways and homes.
The other end of the cycle is La Niña — “Little Girl” — which tends to bring wetter and cooler conditions to the Northern Rocky Mountains and Greater Yellowstone. The pattern oscillates widely, with El Niño and La Niña events occurring every two to seven years and neutral conditions dominating in between.
That brings us to the current cycle. A Super El Niño starts with Pacific Ocean temperatures at least 4 degrees F warmer than an average El Niño. This year’s cycle not only clears that bar, it is on track to reach 8 degrees above average, making it significantly stronger than any cycle peak in the past 35 years.
Unfortunately, the precision of what “significantly stronger” means weakens as the weather pattern moves inland. The U.S. Geological Survey’s El Niño Impacts site for north-central states anticipates above-average temperatures this winter, but adds that its precipitation analysis is “much more variable.” The National Oceanographic and Atmospheric Administration adds that “differences among the models are substantial enough that precipitation should be considered a lower-confidence component of the forecast. The winter may be strongly influenced by other atmospheric patterns and individual storm tracks.”
One common effect of an El Niño is to pull the west-flowing Pacific jet stream winds to the south. This tends to dry out the U.S. states along the Canadian border. However, the shift can also destabilize the polar jet stream, leading to abrupt arctic outbreaks of cold weather.
“When we have strong El Niños, we have more frequent storm systems,” Jensco said. “That can mean four or five more weather systems this winter.”
Other weather watchers, such as Big Sky Resort, are downplaying the Super El Niño impacts. In a Sept. 15 blog post, the Gallatin Range ski area predicted it would receive something close to its typical 400 inches of annual snowfall.
“We don’t get the wild swings that some other mountains do,” Snow Safety Assistant Director Chelan Babineau-Z wrote in the post. “So, while the rest of the ski world speculates, we’ll be here doing what Big Sky always does: watching the weather, firing up snowmaking, and getting ready to spin the lifts on November 25.”
However, just as this El Niño is pushing beyond typical bounds, other Greater Yellowstone weather patterns are showing change too. A recent study published by Montana State University researchers found that winter heatwaves aren’t melting snow in predictable fashion.
The analysis of more than two decades of SNOTEL remote moisture sensor records from 823 sites across the western United States. They found that while heatwaves of three or more days of above-average temperatures produced significant snowmelt, nearly half the sites did not show a corresponding boost in river and stream levels.
“We thought if you melt more snow, it’s natural to expect more streamflow,” MSU civil engineering professor Siwei He told Mountain Journal. “But when we looked, we saw snowmelt increase but not streamflow increase. The meltwater was not recharging rivers.”
He and his colleagues are still working to explain where the water goes; it could be evaporating into the air or soaking into the soil. But more importantly, the discovery means it’s harder for irrigators or fisheries biologists to connect winter snow levels with summer water supplies. The USGS impact site warned that Montana and Wyoming water managers this winter should “consider the potential for reduced snow accumulation and earlier snowmelt.”
A separate effort at MSU will look at using artificial intelligence to improve forecasters’ ability to produce better hydrological outlooks.
“One of the problems is that we don’t have a great understanding of how precipitation forms in clouds and how that results in where, when, how much and what phase of precipitation ends up falling,” MSU earth sciences professor Marianne Cowherd said in an email. “That can have a big impact — we might see rain on one side of a mountain, snow on the other side, and the rain runs off immediately while snow accumulates. We’re often very wrong.”
The MSU project is funded through the U.S. Department of Energy Genesis Mission and partnered with DOE’s Lawrence Berkeley National Laboratory along with the Lawrence Livermore National Laboratory, Boise State University and MSU. It will look at events such as the “Santa Slammer” winter storm that dumped more than 100 inches of snow on the Colorado Rockies in December 2021 and probe why traditional forecasting methods failed to predict the storm’s magnitude. The goal is to train an AI model to produce a more accurate result from the same historic meteorological data.
“AI assumes everything is a perfect observation, so we’re doing a lot of work to create this understanding of what real data can and can’t provide, including situations where we might have more than one instrument measuring the same thing and they don’t agree,” Cowherd wrote. “The process here is developing the software infrastructure and scientific guidance for how to connect this large, large dataset with lots of observations.”
As for this winter and over the next year, NOAA forecasters caution that the crystal ball gets really cloudy.
“There is substantially less confidence in what El Niño will mean for the North Central region during spring and summer 2027,” the NOAA impacts site stated. “The influence of [El Niño] on North American climate is strongest during winter and can persist into early spring, but the relationship becomes considerably weaker and less consistent during the late spring and summer. NOAA therefore cautions against extending the winter El Niño pattern directly into the following warm season.”
