Forecasters agree snow is coming to the Seattle area, but when?

When will it snow? Local forecasters have been predicting snow will fall on or around Christmas in the Puget Sound region, but when and where exactly?

Friday rain into pockets of snow

KIRO 7 Meteorologist Nick Allard says there is a chance of some snow in the foothills around Western Washington closer to 1,00o feet in elevation. Elsewhere, you may see a few pockets of wet snow or rain/snow mix. Most areas will see rain showers and temperatures in the low 40s.

The Fraser River Outflow will start moving in Friday afternoon with cold air possibly creating a convergence zone around Seattle in the later hours Friday and into Christmas morning. Allard says there might be isolated pockets of snow with some accumulation.

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Best bet for widespread snow

The best chance for widespread snow across the Western Washington region will be later Christmas night into Sunday, according to Allard. He says 1-3″ of light snow could fall.

The National Weather Service backs up that timing.

“For those wanting snow, Saturday night through Monday appears more promising right now,” the NWS said in its latest forecast. “If temps are cold enough and snow can materialize, a few inches of accumulation seems like a reasonable outcome.”

Seattle-area atmospheric scientist Joe Boomgard-Zagrodnik agrees, noting that “Seattle will be in the ‘lowland snow zone’ from roughly Christmas Day through New Year’s Eve,” he said on Twitter.

“Will there be moisture? Probably, but timing and possible snow amounts remain unknown,” he added.

Boomgard-Zagrodnik goes into further detail on his blog, describing how “the more serious snow chances begin from the 24th-25th and continue through the 29th-30th,” with ensemble forecasts still making it “next-to-impossible” to pinpoint exact times and quantities for the time being.

“The good news for snow lovers is that almost every ensemble member has at least some snow in the Dec. 24th-29th time period, so we can say with fairly high confidence that Seattle will see at least some snow prior to the new year,” he clarifies.

The National Weather Service has a list of measurable snow on Christmas day in Seattle:

1. 1.8 inches (1909)
2. 1.0 inches (2017)
3. 1.0 inches (1965)
4. 0.9 inches (2007)
5. 0.8 inches (1990)
6. 0.4 inches (2008)
7. 0.4 inches (1915)
8. 0.2 inches (1944)
9. 0.1 inches (1916)

That marks nine times snow has fallen on Christmas day in the past 127 years (records started in 1894).

Temperatures into the teens

In addition to the snow, temperatures will be much cooler Sunday into the new week, Allard says. Look for freezing temps during the Seahawks game Sunday and temperatures into the mid 20s to start the week. Overnight lows into Tuesday could dip into the teens.

Moisture ramps back up Wednesday with another chance of snow.

“The arctic air is going to start pouring through our mountain passes. Even the air over the ocean is going to be relatively cold the day after Christmas,” Boomgard-Zagrodnik said. “It looks like around the 29th or 30th [of December], it will bottom out.”

“It’s been amazing to see some of the predictions. They’re pretty close to all-time records according to some of the outlying models.”

Correction: A previous version of this article incorrectly stated that it has snowed 11 times on Christmas day, when in fact, it’s only been 9 times, as reported by the NWS.

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