Cliff Mass: 8-10 inches of snow ‘possible’ this week after bomb cyclone

An especially strong jet stream over the Pacific Ocean spun off into a series of five or six weather systems, including a massive “bomb cyclone” that hit the Puget Sound region Tuesday morning.

The bomb cyclone brought wind gusts peaking at 40-60 mph early Tuesday morning as more than 100,000 people lost power across Western Washington and Oregon.

“The bomb cyclone has pretty much passed through, so that’s almost history now,” University of Washington (UW) atmospheric scientist Cliff Mass told Jason Rantz on AM 770 KTTH. “And when we talk about immediate logical bomb, we’re talking about a low-pressure system that revs up very quickly. There’s a fancy name in the literature called explosive cyclogenesis. Cyclogenesis means low development, so when it happens very quickly in this certain criteria, we call it a bomb. That’s all it is.”

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This storm triggered the first blizzard warning by the National Weather Service’s Seattle office in more than 11 years, according to FOX 13. And, despite the apex of the storm already behind most Western Washington residents, wind advisories remain in effect through the evening as gusts of 50-60 mph in parts of the interior and 65 mph winds along the coast.

Competing weather models

As for how much snow will be on the ground this week in the greater Seattle area, local climate experts are still debating.

“There’s tremendous uncertainty. I have to be very honest about what’s going to happen being very, very uncertain,” Mass said. “I don’t think we’ll really know until (Thursday) as here’s the issue: It’s going to be cold enough to snow. That we’re sure about. So if there was precipitation, it would at least start to snow. The problem is the models don’t agree on where the precipitation is going to go.”

Mass explained the two weather models are displaying contradicting information. The U.S. model has snow moving into Western Washington on Friday afternoon and evening while the European Center model sees precipitation moving to the south towards Portland, leaving the Puget Sound region and Northwest Washington snow free.

“We could get as much as eight to 10 inches here in Seattle by the time you get to Friday morning,” Mass added.

“Inches?” Jason Rantz asked to confirm. “How realistic is that? There’s no way that happens.”

“It has happened. It’s something we’ve had, but we haven’t had too big a snowstorm,” Mass answered. “At this point, I want to be absolutely honest, we are very uncertain. We have two fairly good models going in very different directions and I think we’ll know what’s going to happen tomorrow.”

Difficulties of forecasting snow in the region

Mass cited that snow forecasting is very difficult in this region as it is right near the edge of the required temperature and right on the edge of the required amount of precipitation.

“If snow happens here in the Puget Sound region, it’ll be Friday afternoon into Saturday morning,” Mass said. “That’s when it will happen and by Thursday, we’ll know.”

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Whether or not snow will fall this week, temperatures will drop to below freezing. Starting Thursday, the nightly low temperatures range as low as 19 degrees on Friday to as high as 23 degrees on Monday before jumping back to the 30s on Tuesday.

“Below-freezing temperatures you can bet on that,” Mass said. “If you’ve got hoses connected outside, you might want to disconnect those. Bring in vulnerable animals. Seattle is going to have to deal with homeless people. This will be dangerous for homeless people no matter what.”

Listen to the Jason Rantz Show on weekday afternoons from 3-7 p.m. on KTTH 770 AM (HD Radio 97.3 FM HD-Channel 3). Subscribe to the podcast here. Follow Jason on X, formerly known as Twitter, Instagram and Facebook.