Among other weather records that were set last week, we just might have seen our shortest fall ever.
Just five days into the autumnal equinox — the fancy Latin term for the swing from summer to fall — much of the Inland Northwest got belted by winter, or at least a distant relative.
The area’s summer, which in itself was significantly cooler than normal, drifted into history on Monday, Sept. 23. And then, bang, here comes the first measured snowfall in September since 1926 on Saturday, Sept. 28.
Officially, 3.3 inches of snow ultimately fell over Saturday and Sunday, easily eclipsing the 1.4 that fell in one day in 1926 according to the National Weather Service office on Rambo Road near the Spokane airport.
The storm, the result of what retired Eastern Washington University meteorology professor Bob Quinn predicted on Sept. 24 would be a cold northerly flow coming down out of Canada. What complicated things and brought the steady snow with mixed rain was that front decided to hang out longer than expected.
“It just anchored over Eastern Washington and Northern Idaho so the end result was a combination of colder air and enough moisture in the low to create the snow,” Quinn explained.
The effects of that stalled system spiraled out over a wide footprint across the region, dropping upwards of two feet of snow across portions of Montana.
But the impact was largely anchored in the Inland Northwest.
Lows like the invader on Saturday “tend to be tight so you can go 200 miles one way or another and the weather’s fine,” Quinn said. The perfect example was Seattle where there were mostly sunny skies.
Last Saturday was also EWU’s Big Sky Conference opening football game against North Dakota where the Eagles prevailed 35-20. And while the contest listed paid attendance at 8,726, many of those either watched from the comfort of their televisions at home, or in the vast tailgating area behind Roos Field as a steady 20 mile-per-hour wind out of the northeast when coupled with a temperature of 35 degrees produced a wind chill in the low 20s.
“Along the boundary of that front you’re going to get a strong pressure gradient, that’s exactly what it did and that gave us the wind,” Quinn said.
The official meteorological start of winter comes Dec. 21 and Quinn was asked to peer into the sea-surface temperatures crystal ball that made him a long-term forecasting expert throughout for much of his 49-year teaching career at Eastern which ended in 2015.
The driver of both our weather — and in some ways that of the rest of the world — rests in systems that form in the northern reaches of the Pacific Ocean. And that water has been warmer than normal, a couple of degrees worth, for the past several years.
It’s not been enough to produce an El Nino pattern, but rather a neutral “La Nada,” the unofficial term Quinn has attached to the phenomena. Three of the past four winters fall under this neutral banner and each has resulted in above the average 45 inches of annual snow measured at the Weather Service.
A weak El Nino, normally producing a drier pattern, was in place during the winter of 2018-19 and still blanketed us with nearly 54 inches of snow.
The opposite, a La Nina with cooler than normal sea surface waters, took hold for four of five seasons starting in the winter of 2007-08. That gave the area back-to-back record snowfall, 92.6 inches in 2007-08, followed by 97.8 inches the next winter.
With a neutral pattern predicted, it promises to bring the best of both worlds to the Northwest, Quinn said. “What that means is you form a large broad trough of low pressure over that warm water,” he said.
And that brings the region two different winter weather options.
One is a high pressure ridge over the Midwest and Rocky Mountains which places the Inland Northwest on the western side of that ridge and the end result is the cold air out of Canada.
Long-term, however, and periodically, the trough will flip the jet stream south ushering in warmer and wetter air.
“I think we’re just going to alternate between those two regimes,” come mid-winter Quinn said. “The dominant pattern is going to be that warm southwesterly flow,” meaning warmer temperatures and more precipitation.
Quinn predicts snowfall to be below normal in the lowlands, but above normal in the mountains.
That’s a positive “perfect storm” of sorts with better road conditions on one hand and ample water supplies come next spring and summer for power, irrigation and recreation.
Paul Delaney was a reporter for the Cheney Free Press from 2007 through 2018 when he retired.
• A record snowfall of 1.4 inches was set at Spokane International Airport Sept. 29. This is the first measurable snowfall recorded on this date since records have been taken in Spokane beginning in January of 1881.
• This brings Spokane`s total snowfall for the month of September to 3.3 inches, making the month the snowiest on record for the city.
• The high temperature of 38 degrees at the Spokane International broke the record for coldest high temperature for the date. The previous record was 50 degrees in 1959.
• Additional record low high temperatures were set at the Pullman-Moscow Regional Airport, Wenatchee`s Pangborn Memorial Airport as well as airports in Omak and Lewiston.