El Niño is officially over. What does that mean for winter 2019-20 in Summit County?
FRISCO — Adios, El Niño.
The National Oceanic and Atmospheric Administration announced last week that a weaker version of the large-scale weather phenomenon has ended. Weak El Niño conditions had been present since fall 2018, allowing for one of the heaviest snow seasons in Summit County in years, including record-breaking March snow totals at the ski resorts.
In making the announcement, NOAA noted that sea surface temperatures in the central and eastern Pacific Ocean had dipped to normal. That means El Niño — which occurs when those surface temperatures are higher than average — is officially over and that the El Niño Southern Oscillation is now in a “neutral” state. NOAA predicts a 50% to 55% chance of current conditions persisting through winter.
What does that mean for Summit County? Your guess might be as good as the experts’. When conditions return to neutral, it means there are no strong forces guiding climate in either direction — the warmer El Niño or cooler La Niña.
The neutral condition is thus colloquially known as “La Nada.” During this unpredictable neutral period, it is very tough to properly forecast regional snowfall in the long term. Other atmospheric and local climate conditions will have more of an impact on snow totals.
Complicating the long-term forecast is Colorado’s location in the center-west of the country, near where the Pacific jet stream flows. Summit County is often stuck straddling the line between cooler and warmer air.
Depending on what course the jet stream takes from the Pacific, Summit can either see higher or lower than average temperatures and precipitation depending on whether the jet stream flows north or south of the county. That adds a whole lot of variability to what Summit can expect.
Regardless of how hard it is to predict snow totals this winter, there are guesses based on history and current patterns.
As of Thursday, Aug. 15, the National Weather Service’s Climate Prediction Center is predicting a 30% to 40% chance of higher than average temperatures for Summit County and the central mountains from November through January. The climate prediction center also forecasts a 30% to 40% chance of higher than average precipitation.
That presents a bit of good news and bad news for Summit County. The higher precipitation is certainly welcome, but higher temperatures lessen the likelihood of epic snowstorms and regular dump days. There is also the scenario where both precipitation and temperatures are average for the season, which would point to average snowfall, as well.
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