Friday, February 5, 2021

Update: Windstorm Overnight Brings 40+ mph Gusts

Maybe you were asleep (like me), or maybe the winds woke you up. Either way, there was a windstorm overnight, with the strongest winds in the South/Central Sound area, north of Everett, and in Eastern WA.

Peak gusts on the NWS map below don’t do the storm justice. Gusts of 45 and 48 mph were recorded in Federal Way and Bonney Lake, respectively.


Was this windstorm in the forecast?

Yes and no. In my previous blog post yesterday, I noted the potential for winds gusting 25-40 mph overnight. However, winds blew past the forecast (pun intended)  and ended up gusting more on the scale of 30-50 mph. 

Why did this windstorm occur?

As illustrated in the graphic below, a large ridge of high pressure sits offshore, and low pressure had formed in the Inland Northwest. Strong winds (black arrow) surged toward the low pressure overnight.


Where and when were the peak gusts?

We will examine two plots of data, from Federal Way and Bonney Lake.

Below, in the data from Federal Way, we see the peak gusts centered around 4 AM. The peak was 45 mph at 4:03 AM.


In the Bonney Lake data, the same trend is evident, with a peak gust of 48 mph at 4:09 AM.


Around 3:45-4:20 AM, we reached our lowest pressure and then pressure began to rise as the influence of the low pressure moved away.

Was there a lot of power outages?

No. Less than 500 PSE customers are out of power. This is likely due to the strong storm on January 13th doing lots of damage.

I’ll have an update later today on more upcoming weather, including more winds and colder temperatures. 

Thursday, February 4, 2021

Breezy Weather Ahead, Rain Shadow, Heavy Mountain Snow

It has been a rainy start to February, with 1-2 inches of rain across most of the region this week. 

Thursday afternoon into early Friday morning will be breezy, with southwesterly winds gusting 25-40 mph, peaking early on Friday. The 5-forecast blend for Puyallup is below. (big numbers are sustained winds, small numbers are gusts)


 These winds will be more of a nuisance than anything else. Be careful for fallen garbage cans, etc.

Additionally, Puget Sound is in the rain shadow due to flow from the northwest.

In the UW WRF forecast below (rain through 4 AM Saturday) you can see lesser amounts in the Puget Sound area due to the NW flow. Our rain will get blocked by the Olympic Mountains. This normally happens to the Sequim/Port Angeles area, but it is reversed today.

Black arrows=NW flow, turquoise line=Olympics blocking rain


The South Puget Sound area will get only 0.04-0.3 inches of rain, while areas north of Seattle and in the Cascade foothills will receive 0.5-1.2 inches. 

This northwesterly flow will contribute to snow in the Cascades. This graphic from NWS Seattle shows expected snow through Friday morning.


Expect wintry conditions on the mountain passes. Another round of heavy snow is likely on Saturday through Saturday night. The UW model below shows accumulated snow through 4 PM Sunday. 


Heavy snow is expected, especially in the Cascades from King County northward, where 1-4 feet of snow are possible, especially at higher elevations.

Let’s just say that mountain pass travel will be quite challenging this weekend.

A windy day is possible on Saturday and then a potentially significant colder pattern is going to move in.


Monday, February 1, 2021

Rainy Start To February

For the fourth year in a row, February has started with at least 0.5 inches of rain. This rain will continue on Tuesday and Wednesday morning, but will likely be a bit more showery instead of steady. 

Below, the UW forecast model shows rain through 4 PM Wednesday. 



Expect 0.3-1.2 inches of rain. This will bring February to 0.6-2 inches of rain in 2 days. It will be drier on Wednesday before a brief system brings rain Wednesday night into Thursday morning.

Additionally, another round of mountain snow will come from Tuesday night to Wednesday morning. This graphic from NWS Seattle shows the expected accumulations.


Expect some snowy conditions if you’re crossing the mountains.

Let’s take a look back at the January rain totals. It was a very wet month!


There were widespread totals of 6-10 inches. This contributed to high soil moisture and some flooding throughout the month.

I’m sure you have heard about the major East Coast snowstorm. Below is a couple articles from The Weather Channel about the storm. I suggest you read them! 

https://weather.com/storms/winter/news/2021-01-30-winter-storm-orlena-forecast-northeast-midwest

https://weather.com/photos/news/2021-01-31-winter-storm-orlena-photos


Next Storm System Hits Western Washington

  8-26 Video Briefing: Next Storm System Hits Western Washington