January 13, 2021

Intense, But Small Low Pressure System and Strong Front Brings Extensive Power Outages around Western WA

It's just after midnight winds are really blowing out there now.....I can hear branches snapping.  Lights are flashing on the horizon and it's not lightning....it is the green colors of transformer fuses blowing.

By 1 AM about 67,000 Seattle City Light Customers have lost power and roughly 308000 Puget Sound Energy customers were in the dark.'  A major power outage for the region.




Winds are gusting to 50-60 mph last night.  The max winds through 5 AM are shown below.  Lots in the 40-50 mph, some as high as the mid-60s.


But if you want to be impressed, the max wind gust hit 121 mph at Alpental Summit (see below).   That is serious wind.


The peak winds at Seattle's West Point reached 51 knot (59 mph)...and peak wind on the Evergreen Floating bridge got to 56 mph.



Where did the strong winds come from?   A small, but intense, low pressure system passed just to our north, producing a large north-south pressure difference (gradient) over western Washington (see forecast map of sea level pressure at 10 PM))


Let me be honest.....meteorological guidance underplayed this seriously.  We knew it would be windy, but the forecast models (such as the UW ensemble) were only suggesting sustained winds of 15-20 knots with gusts to 25-35 kt (see UW ensemble forecast from yesterday morning).  Time is on the x-axis and 06/13 was 10 PM last night.  This shows the forecast of sustained winds (averaged over minutes) at Seattle Tacoma Airport, where the max sustained wind got to 28 knots.


Yesterday evening, National Weather Service forecasters in Seattle could see from the satellite imagery that the low was more intense and tracking upon an optimal path and put out a wind advisory.  

Below is the water vapor image at 10:30 PM last night.  It shows the amount of water vapor in the middle to upper troposphere (roughly 15,000 to 30,000 ft).  There was a pronounced and well defined "dry slot", which shows strong descending air behind the storm....a sign of strength.  The low center is generally at the apex of the dry slot.  This was threatening for western Washington and a short-term warning of the blow that would follow.


Importantly, the European model (ECMWF) produced a far better forecast than the American GFS.  Here are are the maximum winds during the event from the European model initialized (started) at 4 AM Tuesday. Gusts reaching to the mid 50s (mph) over Puget Sound and much higher over the mountains.   Good forecast.

Far less in the U.S. model, with winds only gusting to around 40 mph over Puget Sound.  The European Model did far better with the intensity and track of the low.   I often talk about how the U.S. needs to improve its forecasting capability in this blog...this is a good example to keep in mind.




33 comments:

  1. Power out in waller...tacoma area...out about 1130 and still out as of 145...and still howling

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  2. Can you shed any light on the severe thunderstorm warning that was issued by NOAA for North Snohomish County north to just about Whatcom County between approximately 12:15am to 1:15am this morning? Its 4:01am and the winds here are still crazy strong. We are in the Lake Goodwin area, NW of Marysville.

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  3. Blustery in S. Everett much of the night...but power did not go out until around 4:30 am, and rebounded after about an hour...the winds were seemingly not that powerful...just enough to darken my neighborhood for awhile...this stuff happens a couple of times each winter...not a big deal.

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  4. The dry slot is intensifying over NE Washington as of 6AM.SW 44 G 61 at GEG Spokane now.

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  5. Let's be honest - that was a tough to call but those of us who pay attention to weather updates were getting the message.

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    1. Cliff is the best to warn us, I love him!

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    2. I got it first from Washington Weather Chasers On FB or Twitter but yes Cliff was right there with it.

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  6. Power restored after just over six hours in hills above Longview. 2.23" of rain before signal loss. We will soon see which trees broke ..and where they landed.

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  7. Felt way stronger than 60 mph at my house between Bellingham and Sedro-wooley. Haven't seen a storm like that in a long time.

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  8. The power blinked out then back on here in Port Orchard as a result of a transformer blowing. But more amazingly, we got 5.2 inches of rain in the last couple days.

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  9. Is there any way to see what the radar showed, like, say, at midnight last night? With the sites I use it only lets me see back as much as 2 hours in the past.

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    1. http://weather.rap.ucar.edu/radar/ Has past data. On the UW page you can go back 8hrs, so if you check in the morning you can see the previous night.

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  10. With the passage of the front last night the temperature dropped from 54 to 38 degrees at my house in north Bothell. It would have been real lightning in any other part of the country.

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  11. We lost power for a cumulative four hours here in Kingston. Once from about 8-10pm, then again from 1-3am. I'm looking outside and see my bird feeder stand leaning over, a clear indication not really of the wind, but how saturated the ground is right now and the ease with which trees and power poles could be toppled. Impressive.

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  12. COMCAST went down in Greenwood area (Seattle)!
    911 was called! (no answer from Comcast). Power stayed on. Coffee stayed hot. Whew!

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  13. I'm honestly curious why local weather guru's were ignoring the Euro model? Seems quite contrast to when there's even a single model showing snow or something, it'll make the news. But a major model predicts wind and nobody talks about it.

    I sent this tweet out yesterday afternoon and got responses saying it's just an outlier. https://twitter.com/SharkOnGames/status/1349154348006166529

    Like I've been saying for years now, the biggest wind storms we have almost never make it into the local news, but then when large wind storm predictions are in the news they almost never materialize.

    I'm further frustrated by this, because SE king county is continually ignored in accurate reporting or predictions. NWS Seattle was showing 17mph in kent last night around midnight and 7mph SE (say covington area), yet we were actually getting 60mph gusts at that time.

    And there's almost zero reporting coming from the Hwy 18 area east of auburn, yet that's the are that gets some very high winds quite frequently, just never predicted.

    How can the local meteorologists fix this and become more accureate..while not ignoring major weather models (EURO) when it comes to wind storms?

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  14. Not sure where 'windy.com' gets there data, maybe the European model, but they showed the strong winds that did arrive, pointed right at us in Bow, for a couple of days beforehand. I could also see that the wind direction was going to shift VERY suddenly and it did. Right after midnight the wind direction and speed changed dramatically and i can see that in some data points scattered around the Sound. Our top recorded gust was only 39 but I know that is an artifact of how it captures top gusts/sustained speeds. It was howling and is still pretty strong 10 hours on. No power still

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    1. Windy uses multiple models and let's you select them. By default I believe it's the Euro. I've been impressed with the accuracy of this app especially in remote areas.

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  15. The high wind event extends all the way into Montana.Winds gusting to 76 mph at Great Falls at 1PM local time.And we thought it was windy here!

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  16. 2am-ish: USPS semi-trailer crossing Deception Pass bridge was blown onto the pedestrian railing. The driver must have been terrified. https://twitter.com/wsdot_traffic/status/1349321754632601607

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  17. Some other 100+ mph gusts... Mission Ridge 122 mph, White Pass 108 mph, Chinook Pass 106 mph, Dirtyface Mountain(Lake Wenatchee) 100 mph. 😮

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  18. Looking at personal Weather stations data (Wunderground) wind gusts very suddenly popped to double around midnight, but only for a short time (a fraction of an hour) then it was back to more normal. Power was lost almost exactly at midnight in much of West Seattle for about 14 hours.

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  19. Still need to know about that snow ❄️!!

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  20. Wild ride last night. I woke up to a severe thunderstorm warning, followed by winds that knocked out power and were so loud that I sat in the hallway for 2 1/2 hours. I live on Camano and the trees are huge. Lots of damage.

    I stopped by to see if you'd written anything about the warning, as I've never seen a STW for just wind before. The storm seemed to materialize almost out of nothing. Very interesting experience.

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  21. Power out of the entire San Juan Islands for nearly 20 hours....sad.

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  22. Cliff,
    What is explanation for 'wind shadow' extending from roughly west of Whidbey part way into Straits? Live in Edmonds and no trees down or power out in my immediate area.

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  23. So, Redmond north side here. About 11:30, in the midst of a standard wind storm, we had a really awful gust from the NE (only a few seconds, bigger than anything I've seen since 2002), and about 30 seconds later an identical gust from the SW. This in the middle of a more or less constant s/se wind.

    Was there some cyclonic activity going on? I could track about a 600 to 800 foot swath of destruction from willows road by Digipen, across the slough, up through Redwood road at the Power trail junction, across, up the hill to the NNE, and across our neighborhood (116th and 167ct), and mostly north from there, but trailing off substantially. That does not look just like a windstorm. (Yes, I went out in the storm to shut down our work servers after my power went out.)

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  24. In continuing the trend of naming our big weather events, I'm calling this the Impeachment Day (2.0) Storm.

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  25. I know this is off the wind topic...but just read NOAA report for next 7days and no lowland snow...so I'm guessing the cool down will be upper 30s to low 40s at best meaning lowland snow will be limited to over 1500 feet...so again I'm guessing the lowlands will get shut out...sad I would love some cold sunny days and a little snow...agaun something other than the monsoon rains...mix it up a bit..nothing drastic

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  26. How is that sad? We here in the islands just assume this will happen at least once a year. It’s called living in a rural area.

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