Autumn officially began Tuesday at precisely 7:30 a.m. Mountain Daylight Time. Although, before summer could officially come to an end we had a taste of winter here in Jackson Hole.
Our first snowstorm of the season came on Aug. 3, with snow in the mountains down to just below 8,500 feet. The second storm came Labor Day evening, Sept. 7, with accumulation to the valley floor along with high winds and a multitude of trees blown down.
Officially, 1 inch of snow was measured on the ground in town the morning of Sept. 8. That is the earliest date in September that I could find a record of 1 inch of snow in town. More was reported on the ground north of town that morning.
Records from the town of Jackson Climate Station show that prior to this September, the earliest an inch of snow was recorded was Sept. 17, back in 1944.
What does that have to do with this winter’s outlook for snowfall? Probably nothing. But let’s have a look and see if the trend of cooler and snowier will continue here in Jackson Hole.
What NOAA says
For the winter months, December through February, the National Oceanic and Atmospheric Administration’s Climate Prediction Center shows that temperatures in northwest Wyoming have an equal chance of being above normal, below normal or normal. No help there as far as determining if it will be colder or warmer than the averages.
NOAA predictions for the winter show a better-than-even chance of above-normal precipitation. We are somewhere between a 50% and 55% probability of seeing more precipitation than normal, which we could interpret to mean snowier than usual.
It might be worth noting that last year the same winter outlook issued by NOAA gave us a 50% to 55% chance of having
higher-than-normal temperatures, and it turned out to be colder than normal. NOAA also showed equal chances of above, below or normal precipitation last winter, and we had above-normal snowfall, both in town and in the mountains during winter 2019-20.
What the farmers say
Last year both of the almanacs touted a colder and snowier winter for our region. Check them off as being correct in their predictions for last winter.
This year the Farmer’s Almanac is painting a picture of “cold, above normal snowfall” across all of Wyoming for winter 2020-21. Read no further if that is what you were waiting to hear.
The Old Farmer’s Almanac is a little more ambiguous in its outlook for western Wyoming, predicting “snow pelting, then melting” on its outlook map.
Could that portend warmer weather at times? Perhaps. Nevertheless, it’s not quite as assuring as its forecast from last winter for “low temps, deep powder” — pretty much a dream come true for us here in Jackson Hole.
The bottom line is that none of this winter’s prognostications are discouraging for our area; all of them are a far cry from “warm and dry.”
So, better prep those boards: Snow’s coming.
La Nina on track
Since August 2020, La Nina conditions have developed in the equatorial Pacific Ocean. La Nina is the cool phase of the El Nino Southern Oscillation, or ENSO.
Forecasters at NOAA who pay attention to these sorts of things are predicting a 75% chance that La Nina conditions will continue through the Northern Hemisphere winter.
Typically — and I use that word with a dash of caution — La Nina winters are drier and warmer over California and the southwestern United States and cooler and snowier for the Pacific Northwest and Northern Rockies.
Based on that prediction, along with what I can glean from all the other outlooks, I’d conclude that we are in for another good winter season around Jackson Hole.
Federal weather prognosticators see a good chance we’ll have a lot of snow.
Jim is the chief meteorologist at mountainweather.com and has forecast the weather in Jackson Hole and the Teton Range for the last 29 years.