Update, 8:38 a.m. Friday:
Heads up for the #Everett area – snow moving in will impact areas around the city about 9 AM. Look for reduced visibility and snow to begin accumulating on all surfaces. This will impact I-5. Please be alert to worsening travel conditions in that area! #wawx #wasnow pic.twitter.com/zfQExhYlxv
— NWS Seattle (@NWSSeattle) February 8, 2019
EVERETT — A lot more snow is on the way. Plan for an early afternoon commute, then hunker down.
The National Weather Service says 4 to 8 inches of snow will fall in most lowland areas of Western Washington — maybe less, maybe more — along with cold temperatures and wind starting about midday Friday and continuing into Saturday.
A winter storm warning is in effect from noon Friday to 4 p.m. Saturday for the Puget Sound region and the Cascade Mountains. A winter storm watch is in effect for most of the rest of the state.
“I would expect a bad commute” in the afternoon, said Reid Wolcott, a meteorologist with the National Weather Service in Seattle. “The normal afternoon commute time could be pretty dicey.”
With cold weather expected to linger possibly for weeks, the region was bracing for the possibility of multiple storms in the days ahead. Snohomish County Executive Dave Somers declared an emergency, effective at 8 a.m. Friday, though the courthouse was to remain open all day regardless of weather. Up to 40 county snowplows were preparing to clear unincorporated roads at any given time.
Schools and colleges were either closed or planned early dismissal on Friday, and weekend events were being cancelled.
Cliff Mass, the venerated professor of atmospheric sciences at the University of Washington, calls the coming storm “a much larger snow event than occurred on Sunday night/Monday morning of this week.” In Snohomish County, that storm dumped as much as a foot of snow in places.
“What is forecast to occur late Friday and this weekend is absolutely classic,” Mass writes on his blog. Low pressure over southwest Washington will draw cold air into the state from British Columbia while pushing moist air overhead — “a veritable snow machine.” [Update here.]
The heaviest snowfall is expected between 3 p.m. and 10 p.m. Friday.
Hardest-hit might be the core of metropolitan Seattle — the city and close-in suburbs, including south Snohomish County — with 6 to 8 inches. In Everett and other areas to the north, snowfall is expected to be in the 4- to 6-inch range, the weather service said Friday.
Forecasters are cautious about predicting severity, but the worst case scenario, Wolcott said, is as much as 12 inches of snow in places. In a Friday morning update, the weather service said: “A period of 2-inch-per-hour snowfall accumulation is likely during today’s late afternoon and evening commute in the Tacoma, Everett, Seattle and Bremerton area. Travel is likely to become very difficult.”
“We’ll start to see precipitation creep south” Friday morning, Wolcott said. In Snohomish County, it will likely start around late morning or midday. Friday’s forecast high for Everett is 35, so it could begin as a rain-snow mix. Or it might be all snow. Friday night’s predicted low is 28.
“We may have a convergence zone with this that might change it over instantly” from rain to snow, Wolcott said. A convergence zone is a local phenomenon caused by winds wrapping around the Olympic Mountains and converging, from north and from south, somewhere over the Puget Sound region. The result is isolated heavy precipitation. Snohomish County is a common location for convergence.
“Ground temperatures are cooler, so once it does start to snow it’s going to stick much sooner” than the Sunday-Monday snow, Wolcott said. Temperatures have barely surpassed the freezing mark this week.
The snow will likely end by sometime Saturday afternoon. No snow is expected Sunday, but it will remain cold, so no melt is anticipated.
Then comes Monday. Some computer models suggest an even bigger snowstorm early next week, but predictions this far in advance are not necessarily reliable.
“We’re going to be in this (cold) pattern for a while and may see more snow events in the next week or so that could bring significant snow to the region,” Wolcott said. “It’s difficult to tell whether we have one big storm on the horizon or several little ones.”