Stop building the ark, instead build a snowman!

By Scott Sistek

Summary

November is going out with gusto as our first snow event of the season blows through the area. Snow totals ranged from 3-8" along the Kitsap and Olympic Peninsulas and near Everett to 10-15" in Whatcom County; Heavy Snow Warning issued for Seattle and Everett areas overnight.

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Story Published: Nov 27, 2006 at 5:50 AM PST

Story Updated: Nov 27, 2006 at 5:50 AM PST

Stop building the ark, instead build a snowman!
Updated: Sunday 7:00 p.m. (Heavy Snow Warning issued for Everett/Seattle general areas)

November is going out with gusto with our first real snow event of the season, as a powerful storm came ashore Sunday, cutting through the central coast and drifting over the Central Puget Sound area, before heading into the Cascades.

The hardest hit area is western Whatcom County and the San Juan Islands, where as much as 6-15" of snow have fallen already -- with the snow still coming down Sunday evening.

A spotter outside Friday Harbor measured 9" of snow, while one reader about 2 miles inland from the water near Bellingham reported 10-11" of snow and another in Lynden said they have 15" of snow with three-foot drifts. The State Patrol reports numerous spinouts on I-5 between Blaine and Bellingham and are now asking drivers to use chains in Whatcom County along the freeway. Gusty winds were making near whiteout conditions.

Here's some snow totals as of 6 p.m., with more snow on the way tonight:

Ferndale: 18"
Lynden: 15"
Bellingham: 10-14"
Port Angeles: 12" (toward Olympics)
Maple Falls: 12"
Coville (Clallam County): 11"
Friday Harbor: 9"
Port Angeles: 7" (near city)
Potlatch: 6"
Anacortes: 6"
Sequim: 4.5"
Belfair: 4"
Everett: 4"
Snohomish: 4"
Mukilteo: 4"
Quilcene: 4"
Shelton: 3"
Island County: 2"
Bremerton: 2"

Where Do We Go From Here?

The bulk of the storm was making its way through the Puget Sound region Sunday evening, on its way into the Cascades. But just because the storm's center is about to move off to the east, it doesn't mean the snow threats have ended.

A HEAVY SNOW WARNING has been issued until 4 a.m. Monday for Snohomish and northern King County, including the greater Everett area and north Seattle area. Already 3-6" have fallen in the Everett area, and 1-3" from Seattle north through King County and east to Carnation. An additional 1-4" are possible overnight for areas north of Seattle through Snohomish County.

For Sunday evening, A HEAVY SNOW WARNING remains in effect until 7 p.m. for western Whatcom County, western Skagit County, the San Juan Islands and the northern Olympic Peninsula.

Bellingham, Friday Harbor and Orcas Island were all still reporting heavy snow late Sunday evening with temperatures in the upper 20s and northeast winds to 30-35 mph as arctic air blasts out of the Fraser River Valley.

They could end up with an additional 2-6" of snow by 7 p.m. -- making storm totals range from 6-18". Already, many spots in that area have received 6-12", with a report from Lynden saying they have 15 inches.

For the rest of the area Sunday evening, we'll see a mix of rain and/or snow that will taper off to scattered showers into the early nighttime hours. But there are a few things to take important note of:

For one: Temperatures tonight are expected to drop to right around 32 in Seattle, but into the 20s in all other areas. Thus, where there's snow on the ground, it will likely freeze tonight. Even places where it rained Sunday should get under freezing Sunday night, making for a potentially very icy commute Monday morning. The main Seattle city area might escape problems due to urban heating, but the suburbs need to pay attention.

Second: A Puget Sound Convergence Zone has formed in the wake of the passing storm, and that's keeping the snow going in that aforementioned Heavy Snow Warning area of Snohomish and northern King County, and then stretching west across Island County into the northern Hood Canal area. It is possible this Zone will stretch as far north as, say, Arlington.

That SNOW ADVISORY also extends west to the Hood Canal/western Kitsap County area for another round of snow and an additional 1-4" accumulation -- especially northwestern Kitsap County and southeastern Jefferson County.

Third: For everyone else, there will still be some random snow showers running around overnight. Accumulations will be local, and somewhat random, so pinpointing where and when is impossible. But any shower could be as much as 1-2" accumulation, and could happen anywhere tonight -- even spots that got up over 45 degrees today.

Whew. Got all that? :)

For the long-range forecast, which is for very cold temperatures to continue, check out the Main KOMO Weather Page

When we say "microclimate", we mean "MICROclimate"

Taking a snapshot of Western Washington at 1 p.m. really does illustrate both how variable the weather is around here, and just how difficult it is to predict.

Take a look at this table of early Sunday afternoon observations (noon-1pm):

  • Bellingham: 29, snowing, wind gust to 33 mph (wind chill: 14)
  • Orcas Island: 32, heavy snow
  • Friday Harbor: 32, heavy snow, wind gust 28 mph
  • Oak Harbor: 34, light snow
  • Port Angeles: 33, heavy snow
  • Everett: 34, warming to 36, snow changed to rain. At around 2 p.m., it changed back to heavy snow
  • Seattle: 42, rain
  • Tacoma: 41 rain
  • Olympia: Noon: 37, freezing rain. 1pm: 47, rain
  • Bremerton: 34, dry
  • Shelton: 33, rain/snow mix
  • Vancouver, WA: 50, rain, wind to 40 mph.
  • Forks: 33, snow
  • Hoquiam: 46, rain, wind to 40 mph.

Note that later in the evening, once the storm passed through the Puget Sound area, temperatures around Seattle dropped back to near freezing with snow at times as a north wind returned to the area.

Fun With Meteorology

I'm sticking this at the end for those who like to know some of the ins and outs of the weather happenings in addition to the "how much and where".

For starters, it might be best to peruse our Snow Scenario FAQ Web page. This details all the different ways it can snow around here, and today, several of these events are in play.

  • For the areas under the Heavy Snow Warning Sunday, you're sort of in scenario 1b -- the Snow Overrunning feature. This is where the storm coming into our south draws cold, arctic air from British Columbia south into the region, and then the moisture comes in over the top of the cold air and makes for lowland snow.

  • For the greater Everett/South Snohomish County area, where it has been snowing heavily off and on Sunday morning, but changed to rain later in the afternoon, this I think is more a factor of Scenario 3 -- the Heavy Showers lowering the snow levels. There has been an intense shower hanging over this area, and as all that precipitation evaporates, it takes some of the heat energy out of the air to do so. Thus, it makes the air cooler and in their case -- cold enough to snow.

    Although most of this area has an added advantage of being at between 300-500 feet, which also helps to keep the air that critical degree or two colder. Everett reported 33 and snow during the morning while Seattle was 36 and rain, so you can see how just a few degrees makes all the difference. But as soon as the snow let up, the temperature warmed into the mid 30s and it changed to a light rain.

  • For the Hood Canal area, where Shelton's had a good 3" of snow, you're getting Scenario 4 -- the "Upslope Winds". Remember those east winds coming out of the Cascade Passes we spoke of earlier? Here, those east winds are hitting the eastern slopes of the Olympic Mountains and then rising up the mountainside. As air rises, it cools and condenses, thus squeezing out its moisture. We then mix in a little bit of that "heavy shower lowers the snow levels" from Scenario 3, and you get a localized snow right along the Hood Canal/Western Kitsap/eastern Mason County areas, and along Highway 101 between Shelton and Quilcene.

  • For the King County eastern hills and greater Tacoma/Olympia areas, which had a mix of snow, rain and freezing rain early Sunday, you were in Scenario 2 -- "Dry Air and Evaporative Cooling" -- although there a counterbalance going on that is keeping any accumulations.

    This is also due to that dry east wind coming out of the Cascades. But in this part of the woods, there's an internal battle going on where the winds act to dry out the air -- which helps cool the air by evaporating moisture and using up some heat energy in the process, making the air colder.

    But at the same time, the winds are sinking down the Cascades. As air sinks, it warms up and dries out (like how our heat waves work in the summer). So it's a tug of war between warming up the air, but drying out the air, which makes it cooler when there's precipitation. Make sense?

    It seems the warming process was winning the battle as we haven't had much for accumulating snow reports in this area, and once those east winds stop later this afternoon, you'll be all rain.

    So as you can see, predicting snow around here is quite challenging. You'd think with all the ways it can snow, it'd snow more often, but usually some warming factor sneaks in (not that hard to do with a big warm ocean out to our west) and keeps it rain. But on the times the snow wins out, it sure is amazing to watch!