‘Dice may be loaded’ for November snow in Seattle

Could Seattle see its first taste of snow before Thanksgiving arrives in November? According to one local weather blog, it’s a possibility.

‘Arctic express’ arrives in Western Washington

“Although it’s, of course, impossible to accurately predict the date of Seattle’s first snowfall, I do think the dice may be loaded a bit toward a mid-to-late November snowfall,” Seattle Weather Blog’s Justin Shaw told Patch.

❄️My official prediction for Seattle’s first snowfall of the winter ❄️

Coincidentally—or not?—it’s also the day #Frozen2 comes out. pic.twitter.com/Xa0CjLDuBH

— Seattle Weather Blog (@KSeattleWeather) October 1, 2019

Shaw cites a pair of factors that could play into early snowfall. He first points to a “neutral” winter that will feature neither La Niña nor El Niño, something that has traditionally been an indicator for major November snow events (specifically in 1985, 1996, and 2003). Second, he references the presence of a “blocking pattern” over the Pacific Ocean, similar to the one that spurred February’s historic snowstorm.

That pattern was also what led to a late-September cold snap in Western Washington. According to Shaw, if that had occurred a month later, lowland snow would have been almost assured.

UW climate scientist Cliff Mass has come to a similar conclusion as well.

“If this was November or December I would be warning the Mayor to get the snowplows ready …. but not in September,” he described. “Seriously, the large scale atmospheric configuration is a dead ringer for the one that provides lowland snow.”

Seattle could be primed for ‘very active winter’

Shaw notes that a November snow event this year wouldn’t be on par with February’s so-called “snowpocalypse,” instead estimating between 1 and 3 inches, with areas outside of Seattle being hit the hardest.

“It’s hard to imagine two snowpocalypses in a year,” he noted.

On Monday, Olympia saw its coldest September day in almost two decades. It was also just the sixth time in almost 80 years that the city had seen a low under 30 degrees in the month. Over on the east side of Washington, Spokane already experienced its snowiest September on record — 3.3 inches. On Sept. 29, record snowfall of 1.4 inches was set at Spokane International Airport; it was the first measurable snowfall on record for that day.

All this could be the precursor to what UW climate scientist Cliff Mass predicts will be a “very active winter” for Western Washington, spurred by an unusually early “Arctic express.”

Follow @NickNorthwest