Winter Weather Ahead: What You Need To Know

By now, you have probably heard that cold weather is heading for Western Washington. In this blog post, we will examine the upcoming weather and determine what is certain and what isn't.

To start off, a Winter Weather Advisory is in effect for the blue shaded area (Cascade Foothills) from 6 PM Sunday to 7 AM Monday. 

While all of the Cascade foothills, from Pierce to Snohomish counties, are included in this alert, only select areas will receive the 1-3 inches of snow advertised in the advisory. This is accurately illustrated on the UW model, showing snow through 4 PM Monday.

The UW model shows possible light snow (trace-0.5") in the area south of Everett towards Stevens Pass and a possibility of some light snow (trace-1") across the South Sound. This isn't super likely, but don't be surprised to see some snow overnight into the morning. The best chance of snow (1-3") is in the North Bend area.

Now, let's talk about the cold temperatures that are moving in this week. Arctic air will be moving into Western Washington, with temperatures cooling all week and likely bottoming out on Thursday and Friday.

The forecast for Puyallup from The Weather Channel is below.

Notice that Thursday and Friday will be very cold, with temperatures struggling to get above freezing and lows in the low-mid 20s.

Temperatures could plummet even more than this. The graphic below from NWS Seattle shows the uncertainty in low temperatures on Friday the 12th.

Basically, low temperatures in the Metro area could be as "warm" as 31 degrees, or as frigid as 14 degrees. The average is 21 degrees. Brrr!

Bottom line: it will be COLD!

Additionally, brisk winds out of the Fraser River Valley and Eastern WA will bring very cold wind chills by Friday.

Potential wind chills on Friday and some reminders about the cold from NWS Seattle are below. (click to enlarge)

Wind chills as low as 10 degrees are possible by Friday. This is very cold for our region, and I'll be sure to keep this blog updated about impacts from the cold.

Congratulations! You've made it this far! Now...let's talk quickly about the potential of lowland snow this week. Here's what you need to know right now regarding late-week snow:

• The best chance for lowland snow is Thursday through Saturday
• Uncertainty regarding snow amounts is still very high
• Significant snow is possible but that potential is too uncertain at this time
• A lot of things need to go "right" (or wrong, depending on how you look at it) for a significant lowland snowstorm
• So...stay tuned!!

In short: this will be an active week of winter weather. Stay tuned for updates! 

Update: Wind Advisory Issued, Blustery Day Expected

A Wind Advisory has been issued for the Puget Sound area. The advisory is in effect until 10 PM Saturday, for winds SW 20-35 mph, gusting up to 45 mph. You can view the alert below.

Be sure to secure outdoor objects that could blow around, and be prepared for some downed branches and isolated power outages (not many).

Here’s the wind forecast for Puyallup.

The strongest winds (gusts 30-45 mph) will be today through tonight, with additional winds gusting 20-35 mph through Sunday evening. Expect a similar trend around the region.

Another Windy Day Saturday, More Rain Shadow, and Mountain Snow

After a windy few hours to begin Friday, a similar setup will bring another windy day to select parts of Washington.

The setup that is bringing gusty winds to the South Sound is illustrated below in the UW forecast model for 4 PM Saturday.

Wind will be forced through South Puget Sound, the Strait of Juan de Fuca, and a gap in the Cascades near Wenatchee.

Below, the blend of 5 forecast models for Puyallup. This shows the forecast winds (big numbers are sustained winds, small numbers are gusts, arrows are wind direction).

Forecasts show winds gusting 30-40 mph in Puyallup. Winds will lessen, but still gust 20-35 mph through Sunday afternoon.

North of Puyallup and closer to the water (Tacoma, Federal Way, Des Moines), winds will gust 35-45 mph.

The strongest winds, gusting 40-60 mph, will occur around the Strait and near Wenatchee.

Expect the peak winds in the South Sound to occur between 9 AM and 10 PM Saturday.

Additionally, some rain can be expected with this system, mainly before noon on Saturday. The UW model below shows expected precipitation through 4 PM Saturday.

Notice that Puget Sound is still in the rain shadow due to northwesterly flow. Expect light rain, totaling 0-0.2 inches on Saturday. For areas outside of the rain shadow, totals will be higher, as illustrated by the map.

The lowland rain will be mountain snow this weekend, with the greatest totals from King County northward.

Expect totals of 8-24 inches at the passes, with 2-4 feet at high elevations.

Now...I'm sure that some of you are wondering about the potential of much colder weather and small chances of lowland snow over the next week or so.

For now, it is likely that we will have cold nights, with morning lows in the 20s. Accumulating snow can't be ruled out, but that chance is too small right now. 

One thing is certain...I will have plenty more blogs talking about the cold weather.