Major Snowstorm Hits Western Washington & The Next Storm

A major snowstorm has brought 6-12 inches of snow to the Puget Sound area overnight Friday into Saturday. 

I will have a blog post in the coming days with a detailed recap of what happened during this snowstorm, and the impact (or lack of impact) of the dry easterly winds.

I got a total of 9 inches of snow in Federal Way! (my measurement below). Similar totals were recorded around the area, with less (4-7 inches) near the Cascades, and more (10-15 inches) near Graham and southward.

In last night's blog post, forecast models predicted that the South Central Sound predicted 3-8 inches of snow, with lesser totals due to easterly winds. 

However, the easterly winds ended up being more localized, which allowed for higher snow totals across Puget Sound. I'll have more analysis on this in the coming days!

This storm brought hazardous driving conditions and many roads are impacted by snow and slush. A refreeze will occur tonight, so expect winter driving conditions and take it slow on Sunday.

On another note...the snow sure is beautiful! Enjoy it while it's here!!

Now for the next storm...

Low pressure will approach the Washington Coast tomorrow. Precipitation will likely begin as snow in Puget Sound. Below is a graphic from NWS Seattle showing expected new snow on Sunday.

Expect 1-2 inches of snow on Sunday!

As the graphic says, warm air will likely move in Sunday night-Monday morning. The changeover from snow to rain could be messy. There is a chance of areas of freezing rain or sleet during the changeover. As we know, ice storms can cause major impacts around here, so be sure to stay tuned (I linked some Twitter accounts below).

This will really be a wait-and-see scenario. The certain aspect is that there will be lowland snow on Sunday. The uncertain aspect is how the changeover occurs, when it happens, and what types of precipitation will fall.

Stay tuned to the Twitter accounts below for frequent updates.

NWS Seattle Twitter

South Central Sound Weather Twitter

Bonney Lake Weather Twitter

Scott Sistek (KOMO) Twitter

Shannon O'Donnell (KOMO) Twitter

Morgan Palmer (KIRO) Twitter

Craig Herrera (KING) Twitter

I will do a short update by 12 PM Sunday. Stay tuned!

Post a comment with your snow totals!

Friday Night Snowstorm Update

After a cold day on Friday, with highs barely making it above freezing, the next storm is here. As of 6:45 PM, snow is falling across most of the areas south of Seattle.

A Winter Storm Warning is in effect from 10 PM Friday to 4 PM Saturday. The alert is posted below.

Now for the forecast. Snow will battle dry easterly winds, just like yesterday's system. However, this storm is stronger, and snow will be more widespread.

The forecast graphic below from NWS Seattle shows the snow forecast and the uncertainty surrounding snow totals.

This forecast gives roughly 3-8 inches of snow to the South Central Sound (aka: Tacoma/Puyallup/Lakewood/South Hill/Federal Way/Auburn).

Before we settle on totals, we will take a look at a few more forecasts to get a better idea of how much snow could fall.

The high-resolution University of Washington WRF forecast model shows snow totals through Saturday night.

The South Central Sound gets 5-9 inches in this forecast model. Notice the distinct line separating greater and lesser snow totals. This line, likely over King County, will play a big part in determining where the most snow will fall.

The National Weather Service's HRRR (Rapid Refresh) model, (no image) gives the South Central Sound 3-8 inches of snow, with a significant decrease near the influence of the easterly wind (8" in Tacoma, 3-5" north of there).

Finally, the European Model's forecast for snow through Saturday evening.

Image from Cliff Mass Weather Blog and WeatherBell.

The Euro gives the most snow area-wide, and the South Central Sound receives 7-10 inches.

So, how much snow can we expect?

That will depend on the dry easterly winds. As you can see in most of the forecasts above, the areas just west of the Cascades have less snow. That's the impact of easterly winds on snow totals. Since the easterly winds are dry, they dry out the air and in turn stop precipitation from falling.

The most likely snow amount for the South Central Sound is 3-8 inches. Isolated higher totals are possible.

Since it is already quite cold (25-32 degrees) across the area, expect snow to stick to roads, especially once traffic decreases this evening. Be ready for winter driving conditions.

If you are going to measure the snow that falls at your location, follow these general guidelines below from NWS Seattle!

Feel free to comment on this blog post with your snow reports, photos, and questions! Below are a few good sources for updates.

NWS Seattle Twitter

WSDOT Traffic Cameras

Scott Sistek (KOMO) Twitter

Shannon O'Donnell (KOMO) Twitter

Morgan Palmer (KIRO) Twitter

Craig Herrera (KING) Twitter

Erin Mayovsky (Q13) Twitter

Bonney Lake Weather Twitter

South Central Sound Weather Twitter

What Happened On Thursday & Update On Friday/Saturday Storm

Update 8:20 AM: A Winter Storm Warning is in effect from 10 PM Friday to 4 PM Saturday for the Puget Sound region. The warning is below.

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It has been a cold day across Western Washington. The main weather story of the past 24 hours ending 7 PM Thursday has been the battle between dry easterly winds and the snow. 

From the morning to mid-afternoon, the dry easterly winds won the battle for snow. 

Around 4-6 PM, winds calmed, humidity rose, and snow started falling around the area. Snow has accumulated as well, with a trace to half inch being reported around the Tacoma/Puyallup area.

Additionally, snow is sticking to roads, including I-5 and main roads. (See WSDOT camera below in Federal Way at 9:30 PM.)

An additional trace to 2 inches of snow is possible through Friday morning. The graphic below from NWS Seattle shows this forecast.

It will be quite cold across the area tonight, with lows of 20-25 degrees likely. This will bring icy conditions to wet road surfaces, with some snow possible on side streets. 

Additionally, brisk winds will bring cold wind chills of 10-25 degrees overnight.

Now, our attention turns to the complex forecast for the Friday night/Saturday storm system. The same easterly winds that made it challenging for snow to fall on Thursday will make for another challenging forecast.

In the graphic below from NWS Seattle, we see that the Tacoma/Puyallup areas will likely receive 4-8 inches of snow. 

Even with this forecast, there is still uncertainty. There is potential for a well-defined line between greater totals and lesser totals, likely setting up over King County. That is due to the dry easterly winds.

What you should know is that the incoming storm is stronger than the Thursday storm. Confidence is higher in more widespread snow, but exact amounts, placement, and timing remains somewhat uncertain.

By tomorrow night, details regarding this storm will likely be more clear.

Stay tuned for an update tomorrow evening as the next storm moves in and the forecast will likely be more certain!