December 27, 2022

A Potent Storm with A "Poisonous Tail" Makes Landfall Today

A powerful Pacific cyclone is now approaching landfall and its powerful winds have already caused massive power outages over Oregon, where over 100,000 customers are in the dark as I write this.

Washington State is next.

Infrared satellite imagery shows the large-scale cyclone over the West Coast (see below).  Huge in scale.

A close-up visible image this morning shows the circulation with the low west of Westport.


Now the exciting part: the coastal radar on Langley Hill near Hoquiam is picking up the circulation offshore (see below).   Very helpful.  I always think appreciably of Senator Maria Cantwell when I see such images (she played a critical role in securing the hardware).


The Poisonous Tail

Oceanic midlatitude cyclones have a structure different than cyclones over land, and the current storm is no exception.

Below is the analysis of sea level pressure (solid lines) and wind gusts (color shading) at 4 AM this morning.   You will notice a large pressure change and strong winds on the Oregon Coast, which led to lots of power outages.  

But do you see the strongest winds and large pressure gradients to the south and west of the low center?  That is known as the "poisonous tail".  And that tail will reach western Washington later this afternoon.


The maximum winds from midnight to 9 AM today so far are shown below.  Exposed locations in the coastal mountains of western Oregon experienced 80-90 mph gusts, while 60-70 mph gusts raked the coast.   Southwest Washington had 50-60 mph gusts.  Strong winds also hit eastern Oregon.


The Forecast

This is not an easy forecast.  The winds at any particular location will be critically dependent on the exact path of the low

The UW model forecast has the low weakening a bit and moving across the northern Olympic Mountains by 1 PM, with a huge pressure gradient (and strong winds) over NW Oregon.  Not good for Portland.


By 10 PM tonight the low is in southern BC and a large pressure gradient is over western Washington.  The early evening will be the time of strongest winds over western WA.  Southerly winds over Puget Sound and powerful westerly winds in Strait.  Expect winds to accelerate in western Washington around 4 PM.


The NOAA/NWS HRRR model has a similar solution, and let me show you its latest forecast (started at 9 AM) for the strongest winds through 7 PM.

Strong winds (50 mph+) along the coast and Strait.  Central and northern Whidbey will be hit hard.  50 mph+ gusts from downtown Seattle to Olympia.  Crazy strong winds on exposed higher terrain of the central/southern Cascades.

The European Center model is taking the low on a more southerly path, which would be less threatening.

This storm is typical of one of the stronger cyclones we get each year, but not like one of the majors (Columbus Day, Inauguration Day, Chanukah Eve).  Its track is not optimal, it is weakening on landfall, and other reasons.

If you are living in western Washington, you would be wise to charge your electronics now and prepare for a power outage.  Stay inside during the strongest winds later this afternoon and evening.

42 comments:

  1. The aformentioned "tail" you spoke of came roaring into the valley a few hours ago, with predictable results. 65 MPH wind gusts unofficially recorded just south of where I live (on the edge of the Portland Metro), and of course much higher along the OR coast (over 85 MPH).

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  2. So far, NWS is staying with its earlier forecasts for strong winds from Seattle to the south. I would comment that most of the scary-looking maximum gust winds for Oregon are either at very exposed locations on the coast or at altitude inland. Sea level winds have been much more modest. Oregon has a whole currently has about 7% of power out. Washington is about 1% out, most of which is in Clark County, which has about 15% power outage. What is interesting is that maximum winds in Clark County have been very, very modest as of Noon. Anyway, thanks for the update.

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  3. The euro model appears most reasonable the coastal radar is showing the low moving into NW Oregon which is not favorable for high winds in Puget sound I bet the hhw Will be cancelled this afternoon.

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    1. You will win that bet...no action to speak of in S. Everett, 6:30pm.

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  4. Here in Wedgwood, in NE Seattle, our barometers bottomed this morning, the newer one at 972hPa, and our old, old one at 28.8. Neither is a truly scientific instrument, but they do a sufficient job for us. There's something appealing about viewing an old barometer when the red needle, against the white face, is down in the upper 28 range, and the marker of the previous position is sitting at just over 30 where it peaked during the cold spell. But no wind to speak of. The rain came through this morning, but not exceptionally heavy. We'll see how this storm develops here. The barometer is now at 976hPa.

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  5. I'm betting on a bunch of hype that turns out to be nothing. Yesterday the winds were at the high end of advisory criteria, yet no advisory issued. Today it's a high wind warning, and I doubt even advisory criteria are reached in the central Puget Sound region.

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    1. There was nothing "hypey" about this storm in OR. Multiple fatalities due to trees crushing people in their cars and/or their homes. Power is still out for many in Portland. Try to look at the macro of the event rather than from your own little bubble in the future.

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    2. Did those people who died in their cars REALLY need to be out? The Seattle area had two people get crushed in their car recently in a wind storm because they just couldn't wait to get Halloween pumpkins. PUMPKINS! There was a storm warning and blatant high winds. That couldn't wait? Much empathy for their families, but that was just a bad decision that ended badly. Sorry you got hit hard. People should take the weather seriously but the opposite is common. People think they are invincible in their cars.

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    3. So true, like an invisible shield that surrounds them. Most truckers know to heed the warnings, particularly around the Gorge.

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  6. As of 15:30 in Oly Wa winds are calm and have been for hours. Knock on wood.

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  7. 96 mph winds recorded on Mt. Hood today! This is one spicy meatball of a storm.

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  8. How much more can forecasters be wrong than they are in this area? You all are wrong more than you're right when it comes to actual weather incidents. Never have I seen a profession where ppl can be wrong so often yet keep their jobs.

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    1. One thing: All the cancelled flights over the past week represents a huge loss of data points for the weather models. So, there might not have been the degree of confidence in them as a result. The over hyped warnings might have been a CYA.

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    2. Wrong where? A lot of areas saw gusts over 50 mph. Some areas did not because of small variations in the track of the low and the interaction of that path with the Olympics.
      Cliff was pretty spot on. He said gusts up to 50 south of downtown Seattle. SeaTac Airport saw gusts of 55. The winds in the strait were intense as well.

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    3. The nature of my work is outdoors. Sometimes on ladders. If the NWS issues a warning for my area, I tend to take it seriously. I am not going to take that kind of risk if all the weather resources are sounding off that something dangerous is about to occur. All work activities got cancelled yesterday...I guess as a precaution. However, it is a bit of egg on the face to cancel work and have it be for naught. I view it as safety but clients take a different view sometimes. It's lost productivity. We lucked out and got basically nothing.

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  9. Central Kitsap is dead calm as of 4pm. Think the Olympics will pretty much kill off any further wind or rain and this will be an event for somewhere else.

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    1. Yup...I mean, Everett does experience a rain shadow effect at times...so I guess we now have acquired a "wind shadow" effect?.11:30pm---moderate rain, very little wind..Ho-hum.

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  10. Five thirty pm..S. Everett...little wind, just dark, ominous clouds.

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  11. I measured a minimum barometric pressure of 28.79inHg/975mb at around 6AM today. This is the lowest barometric pressure in my record - similar to what might be observed in a category 2 hurricane. I also calculated that at a water temperature of 45F, a similar reduction in sea level barometric pressure would induce the surface elevation of the water to increase by 15.358" which had it co-occurred with the high tide at Bellingham Bay today would have resulted in a high tide of 10'7" above the relevant tidal datum.

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    1. I was interested in what assumptions you made in your calculation of the "inverse barometer effect" to arrive at a 1.5 foot tidal effect. My understanding is the rough rule of thumb is 1mb can produce 1cm of tidal effect, but this not necessarily a real world number. These large tidal effects tend to occur with pronounced pressure variations over large areas and over long periods of time. Because the water system is dynamic and constantly readjusts and redistributes, short-term pressure changes may produce less of an effect. Anyway, I am curious whether your number is a theoretical calculation or a real-world estimate.

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    2. It's a theoretical calculation which was intended to reflect only the contribution of the barometric pressure depression on the elevation of a geoid with respect to the relevant tidal datum for Bellingham Bay without taking into account wave action/irregularity of a real-world sea surface or the contribution of rises in local streams which feed Bellingham Bay due to the precipitation and snow-melt that day.

      I used the density of water at 45F (which I believe is approximately the temperature of the surface water of Bellingham Bay) to calculate the amount that a column of water at that temperature would rise if the pressure were reduced from the mean sea level pressure of 1013.25mb to 975mb. I found that the density of water at 45F is equal to 999.85kg/m^3. I then calculated that the pressure exerted by a column of water at 45F and 1cm in height to be 999.85kg/^3 * 9.80665m/s^2 (the standard acceleration of gravity) * .0.01m = 98.050792Pa/cm. I then converted Pa to mb (98.050792Pa * 0.01 = 0.98050792mb/hPa) and I then converted from cm to inches (0.98050792mb * 2.54cm/in = 2.49049007mb/in). Next, I divided the pressure exerted by 1" of water at 45F by the mean sea level pressure to find the height of the column of water which would resist, equally and opposite to, that pressure thusly: 1013.25mb / 2.49049007mb/in = 406.847637". Penultimately, I found via proportion that if a column of water 406.847637" high exerts/resists a pressure of 1013.25mb, then a column of water exerting/resisting a pressure of 975mb would have a height of 391.4892". Finally, I subtracted the height of the the 975mb column from the height of the 1013.25mb column which gave me the value 15.358".

      I chose to do this because I was bored and curious and, as someone whose facility with all things quantitative is fair to middling at best, I'm sure there must be ways of doing this that are more elegant/less filled with errors (conceptual and/or computational). However, it is interesting that your rule of thumb results in a value that is very close to my calculation (15.059") for the barometric pressure depression in question (38.25mb).

      Also of note is that it probably makes little statistically significant difference to actually adjust water column height according to water density at water temperatures that might realistically be encountered in Bellingham Bay and because the heights of the columns in any case - barring a landfalling category 5 hurricane - and in that case even still...as barometric pressure on Earth's surface near/corrected for sea level just exhibits a relatively narrow range under all known natural conditions.

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    3. typo correction: "999.85/m^3" - my "m" key is starting to fail...

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    4. Another correction: "...and because the heights of the columns of water are quite large in any case..."

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  12. How was the reporting from the Seattle Times on the flooding in South Park? I know they have missed some of the stuff recently, but it may be beneficial to extend an olive branch when they get some stuff right. https://www.seattletimes.com/seattle-news/duwamish-river-floods-seattles-south-park-neighborhood/

    "A king tide is a high tide where the gravitational pull is amplified when the moon and sun are aligned with the Earth.

    The tide Tuesday morning was 2 to 3 feet higher than what it normally reaches this time of year. Reedy said it was a confluence of factors not tied to climate change."

    I bet they missed other things, but they may be listening to your feedback on this specific issue.

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    1. It was good they did not push climate change. A refreshing change...acknowledged. But the the story missed a critical point. This is a know problem and the city has delayed in bringing the solution on to line, the South Park Pump Station (https://www.seattle.gov/utilities/neighborhood-projects/south-park-pump-station)

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    2. the other missed point was the low pressure.... low pressure causes sea level to rise. This was a major factor

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  13. The King Tide flooding easily stole the show with this one. Not a total bust in the flavor of 16 October 2016, but this is a bit of an embarrassment. It could also be said that there were models that depicted this storm was going to be very localized in it's impacts but still had enough uncertainty to warrant the broad brush over hype. Looking at the radar it seemed like the "poison tail" hit Oregon and the rest of the storm got neutered by the Olympics.

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  14. The maximum windgust at my location today was a rather anemic 37mph though BLI measured a gust of 51mph.

    https://twitter.com/NWSSeattle/status/1607961468758282241?s=20

    https://nwschat.weather.gov/p.php?pid=202212280441-KSEW-NOUS46-PNSSEW

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  15. Happy to report the Wind was very calm here the entire night in Stanwood/Camano area. I appreciate your report Cliff Mass. But I thought it was going to be a pretty bad storm for us.

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  16. Winds seem to be picking up now. I can hear some gusts

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  17. In Tacoma, it was breezy yesterday, enough so that the winds whistled through my old double pained windows (mid 80's) at times and we got at times a good soaking of rain, but nothing like a few days ago. Awoke this morning to no lights having been lost.

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  18. As far as Bellingham is concerned, this turned out to be a non-event from a wind standpoint. There was only a single wind gust over 50 mph (51 mph) at the airport in the morning. This was much less of a wind event than the storm a day earlier. As far as the rest of Washington and Oregon goes, the overall maximum wind gust map does not look like a major regional storm event. There were big winds one some locations on the Oregon coast. Power seems to have returned quite rapidly with few outages in Washington and only some lingering outages, mostly on the Oregon coast (Tillamook County). All of that suggests there was not a lot of damage to the power system.

    It certainly was unusual to have such low pressure without more wind (975.34mb/28.80"). Off hand I do not recall anything close to this low at my weather station before. I certainly would be interested in hearing Cliff's view on why we did not get more wind at the surface. Cliff's prediction were perhaps a bit more than what the NWS, but not a lot.

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    1. The "bomb cyclone" well offshore on 10/24/21 produced barometric pressures nearly as low and with even less wind. The minimum pressure at my location was 28.93inHg/979.72mb and the peak wind gust I

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    2. The "bomb cyclone" well offshore on 10/24/21 produced barometric pressures in the Bellingham area nearly as low and with even less wind. The minimum pressure at my location was 28.93inHg/979.72mb and the peak wind gust was 36mph. The minimum pressure at BLI was 28.98inHg/981.42mb with a peak wind gust of 44mph. It looks like the minimum pressure at BLI on 12/27/22 was 28.81inHg/975.66mb.

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    3. Also the extreme barometric pressure depression was of less duration during the recent event (~31hr <29.5inHg) compared with the "bomb cyclone" last October (~46hr <29.5inHg).

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    4. Actually the peak wind gust at BLI on 10/24/21 was only 40mph.

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    5. Presumably winds were relatively weak in Whatcom County because the strength and orientation of the pressure gradient wasn't favorable to support high (or even advisory level winds). This could be because of the position and track of the low itself and perhaps, additionally, because these features contributed to terrain-induced "bottlenecks" as in the case of Fraser outflow across Whatcom County being weaker than the YWL-BLI pressure gradient would suggest when the isobars are inordinately concentrated over the Coast Mountains of British Columbia which "bottles up" the outflow in that area rather than permitting it to blast out of the Fraser Canyon and across Whatcom County as it does when the pressure gradient is more favorably distributed/oriented. Of note is that, of the sites reported by NWS Seattle as having recorded wind gusts of 35mph or higher, only 7 are located at an elevation of at least 1000' asl (an unfortunately small sample size to be sure) and of those, only 2 recorded peak gusts of more than 50mph. Both are located in very close proximity to and northeast of Mount Rainier. Even the Pan Dome anemometer at 5020' asl located in the Mount Baker Ski area only topped out at measly 41mph. So it would appear that the strongest winds were largely localized to a few favored locations regardless of elevation. A total of 84 sites reached the 35mph mark or above including 15 maritime stations.

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  19. You brought up the coastal radar. When I first moved to this area and we didn't have one, I did write to both of our Senators. Only Maria Cantwell replied and told me she would work on it, and later I got a follow up from her when it was approved. I have always remembered that and it's one reason I do appreciate her.

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  20. This comment has been removed by a blog administrator.

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  21. Was lots of noise and two trees down on my property, and I'm fairly far north in wa.

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