December 26, 2022

The Upcoming Windstorm (Plus Another One This Morning)

 There is a lot of wind to talk about in this blog--a significant Pacific cyclone will make landfall on the Northwest coast tomorrow....and strong winds will result.

But before I get into that, there was a blow this morning in western Washington as a powerful cold front went through from roughly 7-8 AM.  Below is the Camano Island radar image at roughly 7:15 AM below, with the arc-shaped frontal feature in yellow to red.


This feature is an intense narrow cold frontal rain band, and was associated with winds gusting to around 50 mph, a rapid wind shift, and a significant temperature drop.  The models had it, but underplayed its strength.    

The maximum winds this morning are shown below. 55 mph at SeaTac, 59 mph in Bellingham, and over 60 mph on the coast.  No wonder there are about 100,000 customers out of power in the region.


The Storm

But this is just a "warm up" for the event of tomorrow afternoon and evening.

Offshore, satellite imagery shows a massive cloud feature over the northeastern Pacific, something characteristic of the stronger storms.


The latest UW model forecast of sea level pressure (solid lines) at 10 PM tonight shows an impressive 970 hPa low center off the southern Washington coast, with a very strong pressure gradient (change of pressure over distance) to the south and west of the low.

This is a classic structure for marine midlatitude cyclones.   At that time there will be a strong north-south pressure difference and strong winds from southern Oregon to the Bay area.


Twelve hours later (10 AM Tuesday) the low makes landfall on southern Vancouver Island and a hyper pressure gradient builds over the Oregon coast.  Expect winds gusting to 60-80 mph and power outages along the coast and in the Willamette Valley at this time.


But the interior of western Washington will get its turn.  By 4 PM tomorrow, the low will move into southern BC and an intense pressure gradient will develop over the western Washington lowlands, producing powerful southerly winds gusting to 50-65 mph.  More power outages are probable, particularly with saturated soils.


But the strong wind fun is not over.  As the low moves inland, a large east-west pressure difference will develop over the Strait of Juan of Fuca, producing powerful westerly winds that will bring problems to Whidbey Island and Snohomish County.

To illustrate, the predicted wind gusts at 9 PM tomorrow are shown below.

Just to be clear.  This is not the Columbus Day storm.  Or the Chanukah Eve storm of 2006.   But this is a significant event and some will lose power.    Please keep away from trees during the strongest winds tomorrow afternoon and evening.  

We are close enough now in time to be confident that a major blow will occur tomorrow.  So make sure your batteries are fresh and your electronics are charged up.



15 comments:

  1. Cliff, the nws Seattle sn't on board with the windstorm why the conflict?.

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    1. Actually they are in agreement. Those warnings are issued by the NWS and their website (weather.gov) is showing the same thing.

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    2. There's not even a wind advisory for western or a high wind warning.

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  2. We lost power briefly just before 8:00 a.m. That wind storm blew down a tree across Tokul Rd SE, which I called in to 911 at about 9:10 a.m. The county had the road cleared by the time I finished the morning's shopping at 11:15.

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  3. Thanks for all the content Cliff. Are you aware of any data analysis done on the PNW regarding the temperature and precipitation impacts of different ENSO levels? All I can find is very generalized information. Thinking of exporting some NOAA data and making my own but thought I'd ask you first.

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  4. At 1:30 pm now, in S. Everett...there is an almost eerie calm right now...no trees bending, no branches hitting the neighborhood streets as did happen this am...This is truly the "calm before the storm". Thanks for all you do Cliff, to prepare us for such events.

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  5. Thanks for the update, Cliff. Great info as always.
    The area of highway 2 from Gold Bar to Index got hit VERY hard a few days ago and some people are just getting back to normal. Is there any indication of how hard this storm will hit this area?

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  6. There are actually several storms lined up through this week and into next Monday

    https://youtu.be/q0GBgMJMEV4

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  7. Wind advisories issued earlier today for the entire Wiliamette Valley, but the coastal areas look to be in line for worse.

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  8. Does Camano generally get protected by Whidbey, and consequently have lower wind velocities?

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  9. I measured a 52mph gust at my location in Bellingham at 6:21AM on 12/26 - the highest wind speed I've recorded since December 2018. The temperature reached 60.1F from 4:06-4:07AM - the highest temperature I've recorded since October 20. This month has had a temperature range of 52.4 degrees (60.1 - 7.7) - the largest temperature range for any wet season month in my record and second only to that of June 2021 (96.6 - 42.8). This December is on track to be a top-10 coldest December for BLI - colder than last December. The average temperature from 11/1/22 - 12/26/22 has been 35.25 - the coldest 2-month period in my record. Also, the barometric pressure has dropped precipitously today - 23.4mb in 16.85hr - apparently a bomb cyclone in the making and still dropping rapidly. This is shaping up to be one of the lowest barometric pressure readings in my record. The current record is 979.7mb during the bomb cyclone of October 2021.

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  10. Cliff, below is a copy and paste from forecasts issued out of the Portland, OR NWS office dated 12/27/22 at 0407. Are they using a new model we should be aware of?
    HIGH SURF WARNING IN EFFECT UNTIL 6 AM PST EARLY THIS MORNING EAST OF MULTNOMAH FALLS... <>


    ...COASTAL FLOOD WARNING IN EFFECT UNTIL 10 PM PST THIS EVENING BELOW 9800 FEET... <>

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  11. Based on current radar and satilight the low is moving se towards Astoria I think the hhw for Seattle will be cancelled today forecast bust.

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  12. What happened? The low and most winds vanished ~4PM over Sequim. Here's a timeline video from Ventusky.
    https://macmillen.com/temp/low.mp4

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  13. Just got power back here in mid Willamette Valley. Most areas locally had power by yesterday afternoon. There was some problem with a power line down to the west of us. As far as I could tell from National Weather Service both Eugene and Corvallis recorded maximum winds of 41 mph.

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Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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