Strong La Nina forecast for Aspen’s winter may be good news

The National Weather Service is predicting a La Nina weather pattern to continue through this winter and probably into the spring, with higher temperatures and below average precipitation for the Southwestern U.S.

But before you go turning in your ski pass because it hasn’t snowed in nearly two weeks, remember that Aspen is usually right on the bubble — either the top or the bottom — for the La Nina/El Nino patterns, which appears to be the case this year, so it could go either way.

Or, as meteorologist Cory Gates at Aspenweather.net put it in his recent winter 2021-22 outlook: Six of Aspen’s 10 snowiest winters have been the result of La Nina.

That fact comes with a major caveat, however.

“The bad news (is) our driest winters of all time are also La Ninas,” Gates wrote in the forecast. “It’s very hard to predict La Nina winters.”

La Nina winters stem from cooler-than-average temperatures in the Pacific Ocean and tend to push the jet stream and winter storms further north in the United States. The opposite pattern — El Nino — occurs after prolonged warmer-than-average temperatures in the Pacific force the jet stream and winter storms south.

According to an analysis released Nov. 11 by the National Weather Service’s Climate Prediction Center, temperatures across most of the equatorial Pacific Ocean were below average, indicating a strengthened La Nina this winter.

“La Nina is likely to continue through the Northern Hemisphere winter 2021-22 (90 % chance) and into spring 2022 (50% chance during March-May),” according to the analysis on the Climate Prediction Center website.

For December, the CPC predicts that southern California, southern Nevada, a small corner of southwestern Utah and all of Arizona and New Mexico will see below average precipitation. Most of Colorado lands in the “equal chances” for above or below average precipitation for December, while all of the state is expected to have above average temperatures, according to CPC monthly outlooks.

The December-through-February precipitation outlook still has the Aspen area in the “equal chances” for above or below average snow, though the bottom quarter of Colorado is predicted to have below average precipitation during that time. The chances for above average precipitation drop for Colorado as spring descends, with below average precipitation creeping closer to the Aspen area for the periods between January-through-March and February-through-April, according to the seasonal outlooks.

Gates, who specializes in Aspen-centric weather forecasts, predicted this winter will be above-average when it comes to snowfall between Oct. 1 and May 1. He predicts 360 inches at Snowmass (average 320-330 inches), 350 inches at Aspen Highlands (average 320-330 inches), 320 inches at Aspen Mountain (average 290-300 inches) and 166 inches of snow in the town of Aspen itself (average 146-156 inches).

And it could be bigger than that.

“My gut, which I rely on a lot, says my numbers are too low and that more snow could happen,” according to the Gates’ forecast.

On Friday, Gates continued to believe in the above-average snowfall forecast, said Ryan Boudreau, co-owner of Aspenweather.net.

“He’s sticking to it,” Boudreau said. “He said, ‘I’m still saying it’s gonna be a good winter.’ He’s very adamant. He thinks (snowfall) will be 10-to-12% above normal.”

And while it may seem like winter is starting slowly, records from Aspen’s water plant indicate that only seven of the last 40 winters saw snowfall that was more than 10% below average or normal, according to Aspenweather.net.

“That means 82.5% are normal or above in the last 40 years,” Gates’ forecast states.