December 19, 2018

Another windstorm will hit the Northwest on Thursday

Mother nature is throwing everything in her cupboard against us this week.   We had the first major Pacific cyclone/windstorm, lots of snow in the mountains, heavy mountain rains, a downslope windstorm event on the Olympics, and an EF1-2 tornado.   Meteorological heaven for those who like a good storm.

But the strong storms are not over yet, and Thursday will bring another strong Pacific cyclone to our coast, with strong winds and power outages for many. 

Here are the latest forecasts from the UW WRF model.  We are close enough in time that this evolution should be fairly accurate (and the spread of the ensemble is not that great now).

Let's start with the forecast sea level pressure map at 1 AM Thursday.  A 991 hPa low center is found offshore, with a strong pressure gradient (large change in pressure with distance) off the Northwest Coast.  Thus, strong coastal winds (probably gusting to 30-60 knots) would be in place over the water at that time.

The storm, moving northeast makes landfall on Vancouver Island, and is over southeast BC by 1 PM Thursday afternoon (see below).  The region of strong pressure gradient is over western WA at this time, and particularly NW WA.  Winds would be revving up over inland western WA by this time, peaking a few hours later over Puget Sound.

Let me show you high-resolution forecasts of the surface winds. At 4 AM, wind gusts will have reached 50-60 knots, along the coast, and nearly as high near Victoria and the southern San Juans.  Also note a strong Olympic mountain wave, with strong flow descending the northern slopes of the Olympics.  Deja vu all over again.

By 10 AM (18 UTC), winds rev up in Puget Sound (gusting to 30- 40 knots), with big winds remaining along the coast and San Juans.

 Then the final stage of the wind action, as the low moves by to the northeast, a strong onshore pressure gradient will develop and a westerly wind surge will occur in the Strait of Juan de Fuca (see map for 4 PM on Thursday).   If you were planning a ride on the Victoria Clipper between Seattle and Victoria tomorrow afternoon, bring plenty of Dramamine--it will be a very rough ride.

This event probably won't be more intense that last Friday's windstorm over Puget Sound, but potentially stronger over NW WA and the coast.  There is some variability in the exact landfall position, and  small error could have a big impact on the winds, so keep watching the forecasts. Make sure your batteries are fresh, your barbecue has gas, and your smarphone is charged.


  1. We still need the rain here in NW Oregon, but some more snow would definitely help things in the long run as well. Too warm for any decent accumulation, at least as the forecasts indicate right now.

  2. Why is Tacoma under a high wind warning and olympia is under a wind advisory? Different pressure gradients?

  3. Trick with these digital forecasts is not to slice them too fine. Differences in winds forecasted between Tacoma and Olympia is an example. It's a bit like parsing "really windy" versus "very windy".

    For me, out along the Strait, it means stacking a lot of wood inside next to the fireplace, being prepared with headlamps and candles and blankets to be comfy with the power out (my three Labs are great bedwarmers), have food that only needs my gas stove top or BBQ to prepare, and stay indoors when the wind blows to avoid falling whatever. Oh, and have lots of wine (or whatever you drink or smoke) available.

    In other words, a storm party. All goodness.

  4. One of the problems with the NWS websites is the large amount of information and finding the most relevant place to go. I do not find the sites highly intuitive, but with some persistence, I am able to dig out useful things. One of the pages I visit during the course of a weather event is the Weather & Hazards Data Viewer site ( which enables you to see the progress of an event by looking at data from reporting sites, which are numerous.

    Recently I came across another set of pages the NWS refers to as the "Weather Story." Not sure when this was added, but it provides a little more visual detail compared to the basic forecast page and in some ways works a little better for communicating than the discussions in that if often highlights specific areas on the map that are expected to be impacted.

  5. Is it my imagination or are the storms this year more energetic than normal? If so, what would be driving this?

  6. The "Weather Story" feature is on many WSFO sites across the country. Here's a map to those that are active...

  7. This comment has been removed by the author.

  8. Is the low staying on forecasted track? From current satellite imagery, it appears to be just off Tofino, BC. Will it hit the proverbial "sweet spot," which generates strongest winds?

  9. I am seeing a faint eye in the center on the radar. Is this an anomaly?


  10. "If you were planning a ride on the Victoria Clipper between Seattle and Victoria tomorrow afternoon (today), bring plenty of Dramamine--it will be a very rough ride." - Cliff Was 19DEC18

    I am not sure what "plenty" means in this context? They do give both a Dramamine does and an alternative protein bar to Dramamine before your trip on The Clip.

    Hmmm. Are you a physician, Dr. Mass? Are you saying we should ALL take Dramamine on the Victoria Clipper? In fact, in severe water as you forecast, they will cancel voyages instead of risk the expensive new ships they have purchased, and to save lives at seas.

  11. Looks like they hit the forecast pretty well here in Bellingham. Trying to figure out if the worst of it has passed as of 11:30 am. There were 2 60+ mph gusts at the airport shortly before 10 am. Since then, gusts in 40's to low 50's, with continuous currently in the 30's and appearing to be on the decrease. Unfortunately, some of the wind data feed from the airport stopped as 11:10.

    Temperature starting dropping at 11 am, so perhaps the front has passed. See blue sky clearing to the southwest.

    Keep waiting for lowest barometric pressure. It keeps teasing me as to whether we are past the bottom.

  12. Thursday at noon - stone on string at BOW-WA station is listing at about 45%. Bad boating and leaf raking. But stone is dry ...

  13. I was probably optimistic, but regrettably the Bellingham Airport wind instruments look like they died (probably from a big gust). Ferndale has reported a couple of 70+ gusts. Gusting in the Bellingham area has been all roughly at the same time.

  14. Gale force winds blowing now through the Skagit River gap. Lights flickering like a disco ball.

  15. TW B, I do believe that it is your imagination. We typically have a strong windstorm by October or November here. This year, we had no significant wind until last week's storm, and even then it was only a mild event. Having the leaves gone from the trees was also quite helpful.

    Think of past years when all of Woodinville was out of power for weeks. This year has been comparatively benign.

  16. It’s interesting that with all our knowledge we have managed to collect we can only describe how the cyclone developed in Port Orchard, that’s like Monday morning quarterbacking
    Incredibly useless science in that regard

  17. I think what is a bit unusual is the lateness of these typical fall storms rather than their intensity (other than the tornado). We are getting storms often experienced in late October to Thanksgiving in late December. It seems warmer this year as well. Perhaps Cliff can tell us how many standard deviations from the norm this really is (not counting the tornado).

  18. What is a “typical fall storm”? Do they differ from other storms we have here? The Inauguration storm of January 1993 (when the I-90 bridge sunk)? The Feb 13th 1979 storm that sunk the Hood Canal bridge? The Dec 14th 2006 Hanukkah Storm (it has it's own wiki page)? Or the other 38 ranked storms (out of 52 listed in the link below) that were in Dec to Apr – what makes them different? Were they also "late"?

  19. This storm produced the highest winds (57MPH gust, 25MPH 10MIN sustained) that I've measured since 2016.

    I've measured maximum monthly gusts of 50+MPH from October through March since measurement commenced October 2015.

  20. High winds certainly materialized here on South Whidbey Island. Branches and some trees down. One mature Douglas-fir dropped and went through a neighboring home. No power.

  21. Anyone remember the Christmas storm of 1964? Down here near the Columbia River Gorge, we experienced record low, record snow, record rain, all in one week. I don't think we had a record high, but the temperature did jump up into the 50's to instigate the big snow melt. Topped with the snow melt and flooding, the coast had high tides. California, Washington and Oregon were declared disaster areas. I remember the bitter cold east winds while the temps were down in the minus digits. When the "Chinook Winds" arrived the coast was hit with 80 to 100 mph gusts.

  22. Yes, what's really unusual is the "lateness" of these Fall storms. Much later than normal. What's that, you want me to define what "late" actually entails?


  23. You are correct, they are late! Also the fact that we have a city of 700,000 in Seattle means when we hear 30,000 homes without power is only 4% of the population, not 10%. I am happy for snow in the mountains and rain in the city.. I remember 1964 and all the pineapple expresses in between. I was a windsurfer and installed WEA stations east of Roosevelt, WA. Before there was an iWind.

    I like good stories and anectdotes, too. But this has nothing to do with statistics. If people are more concerned about climate change, more power to it. Science and events move on. Now NAS, WMO, and IPCC publically say that individual weather events should be analyzed as potential climate change events. For those stuck in 2010, good fortune!

    Happy Holidays!

    —-* Dr. Kenneth M Beck

  24. Blogger sunsnow12 said...

    "What is a “typical fall storm”? Do they differ from other storms we have here? The Inauguration storm of January 1993 (when the I-90 bridge sunk)? The Feb 13th 1979 storm that sunk the Hood Canal bridge? The Dec 14th 2006 Hanukkah Storm (it has it's own wiki page)? Or the other 38 ranked storms (out of 52 listed in the link below) that were in Dec to Apr – what makes them different? Were they also "late""

    First, your link to the Pacific Northwest storm analysis is a great one. I have been here my entire life, being borne in Seattle, growing up in Portland and moving back to Seattle in the 80's before retiring to Bellingham 3 years ago. The 1962 Columbus Day storm was my introduction to windstorms. I have been through many on the list, including living on my home-built sailboat on the Willamette river during the November 1981 storm.

    While it is clear we can have major windstorms from October to April, I wouldn't want to argue which, if any, of the three storms we had in the last week would get on the list of major events.

    I made my comment based more on how tame November of this year seemed to be. In my recollection it is pretty common to have 3 or 4 storms stacked up in November and coming into the Northwest and bring a fair amount of wind. This year not too much happened in November. I was just wondering whether the seasonal shift of the jet stream to the south has been delayed from November to December. Temperatures for both months seem warm. Seattle November precipitation was very low until the last 2 days of the month, which reflects low storm activity. December is still warm. Even though Dr. Mass refers to this as being an El Nino year, the last time I looked on the NOAA website, they still were not classifying it as such even though it is predicted to occur.

    1. I've still been messing around with the statistics from Climate at a glance.

      Virtually no warming in the month of December for PNW. Not in the short, mid or long term records.

      Then, a LOT of warming In January!
      More so than any other month. Go figure.


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