Saturday, September 7, 2019

Major Convective Event, with Heavy Rain, Lightning and Thunder, Moving Through Puget Sound

An unusual major lightning/thunder event is occurring over Puget Sound, delaying the UW Husky Game. 

And interestingly, the UW WRF model forecast the event earlier in the day.

The radar at 8:15 PM shows the action, with the red colors being very heavy precipitation within convection.


The view from Husky Stadium was amazing.   Good idea to get folks off the field and out of the stands.
Picture by Peter Benda


The WWLLN lightning network shows extraordinary amounts of lightning over the area.  Here is the lighting totals for the 30 minutes ending 8 PM.   Puget Sound is being pummeled by lightning!

What is really amazing is the large number of power outages associated with the lightning (see below).  Seattle's system is poorly protected from lightning because it is so rare.


The convection is associated with a very sharp upper trough that is making landfall, coupled with some unusually unstable air over western Washington. Here is the upper level (500 hPa) map for 8 PM Saturday...very sharp trough making landfall.



Forecasts were very good.  Here is the high resolution WRF forecast initialized 5 AM this morning showing the 3-h rainfall starting 8 PM.  Impressive.

Update Sunday Morning

Here is the incredible lighting strike map for the 24 h ending 1 AM.   Thousands of lighting strikes with hundreds over Seattle alone.  Amazing.


The tops of the thunderstorms were exceptional for around here, with some reaching 35,000 to 40,000 ft.    Here is an example of the radar echo top at 8:19 PM...the top was 36,000 ft.  Normally, we get excited when tops get to 20,000 ft in western Washington.


40 comments:

  1. Any chance of Alabama being hit by this weather? :)

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    1. Only if NOAA backed this one up as it did the other one ;)

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    2. Ok good grief so critical of everything and everyone...give it a rest perfect person.

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  2. I'm at a wedding in Seattle and it's like the skies are celebrating with us. This is awesome!

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  3. Amazing light and sound show in Clearview at 9 pm! In 30 years here I’ve not seen such a loud or long-lasting storm.

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  4. Wild show and waves of rain on I-5 near wild waves around 8 pm. More like east coast weather. Sensibly most people slowed down.

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  5. Definitely the best lightning event since August of 1999! That event started in the afternoon and had about 2.5 hours of good lightning (with a few breaks). This event had about 90 minutes or so of good lightning, so not bad! Still nothing on the July 1984 lightning storm (3+ hours of nearly nonstop lightning), but the best in years for sure!

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  6. "And it should not be a surprise.....the event was well forecast earlier in the day."

    Perhaps you predicted this weather event Cliff but NOAA certainly did not. As per the Area Forecast Discussion from 1:53PM PDT

    .SYNOPSIS...The next weather system will begin to impact the area tonight, with thunderstorms developing, mainly over the Cascades. A stray storm or two cannot be ruled out over the Puget Sound lowlands.

    Around sunset, that forcing will diminish. However, a band of mid-level vorticity associated with the negatively tilted trough off the coast will push NE into the region this evening and overnight, resulting in ample dynamic forcing for storms to continue well into this evening and
    overnight. This evolution would result in an area of thunderstorms over the Cascades in OR gradually pushing north into WA this evening and overnight. While instability has been fairly well stifled in the Puget Sound lowlands thanks to the stratus deck, we cannot completely rule out a stray thunderstorm developing in the lowlands. -Wolcott-"

    A stray Thunderstorm possibly developing? Not even a hint of the widespread storm activity that was actually observed, not over the cascades at all, but over the lowlands lasting several hours. Is this an issue with forecasting skill or the limitations of the GFS vs alternate models?

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    1. Exactly correct Jimmy! After I arrived at Cliffhanger sports bar (in Lynnwood), I checked the NWS website @~ 8:45 pm and the 1:53 pm forecast discussion was still posted. However, the graphic on the home page warned of lightning (somewhere). I played pool with Rory, a bearded, middle-aged man. He told me he walked a mile to this bar, during the storm. His hooded jacket was sopped. Rory said he likes the feel of thunder against his chest and the sensation of electricity in the air! He's bolder than me. Lightning strikes in Lynnwood knocked out the power for ~ 5 seconds, on the N side of 176th St SW, and then knocked-out residential lights on the S side of the road about 20 seconds later - while I was driving along (each strike very close)!

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  7. The storm hit Bellingham and lasted in fury from 9-10:15pm. I have NEVER in my 60 years seen anything like this in the PNW. Last time I saw a lighting storm this severe was in Texas. I counted 150 flashes in 10 minutes. Zig-zag and sheet lightning with many direct hits in the neighborhood. The noise was deafening and earth-shattering. Power is out all over the area. Torrential rains that caused drainage overflow in streets gutters.

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    1. I’ve lived in Woodinville for almost 30 years and can’t remember another local event with lightning activity on this scale. I’ve spent a lot of time in central Colorado and southern Florida, and while the rain may not of been comparable to some Florida downpours I’ve been in, the lightning activity was definitely comparable.

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  8. I grew up in Oklahoma and have missed thunderstorms like crazy since moving here in the late 80s. If we get any at all, they are typically brief, with a few lame peals of thunder. I was in ecstasy this evening while hearing the long, loud, rolling thunder. THOR! And I don't think that I have ever seen such spectacular lightning, even on the prairie.

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  9. Only if NOAA is backing it up as it did the other one ;)

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  10. Awesome in Kingston and North Kitsap, from the hour-long light show preliminaries, then the surrounding wrath crackling overhead for another hour before pouring rain that ended with the thud when the power outage seemed to end nature`s performance.

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  11. That was fun. We had something similar in 1980; but as in all things recalled, it was just a little bolder and louder.

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  12. Very impressive post, put together just minutes after finishing your Ocean Shores talk. You also had to deal with a poor WiFi signal.

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  13. Was this a record for number of strikes in a day in Washington?

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    1. Not likely. These kinds of storms are not uncommon in Washington, especially up in the Cascades or in Eastern Wa. Just less common in Western Wa.

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    2. I second that question! I've lived in Seattle for 30 years and I can't remember a lightning storm that was remotely comparable. I stood in the rain for a half hour enjoying the show.

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  14. We watched through the whole storm here in Bellevue... Recorded it, too. The strikes were so bright!

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  15. In 2007 a storm like this rolled through Ocean Shores, and in May 2017 a storm almost exactly like this rolled through Lacey (with a micro burst that took out fences with 70 mph winds and 2500+ lightning strikes).

    Rare, but not unheard of. Excellent show.

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  16. The Bow WA "Rock on a String" has quite the light, boomer, and wetting show too!!!!

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  17. Here in the eastern part of the state night turned to day at about 3am with near continuous lightening. Most of us were awake listening to scanners or reading FB reports regarding fire and emergency response. Several fire starts, numerous smoke checks and a couple of debris flows.

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  18. Set up with my camera in Seattle near South Lake Union and got more good lighting shots in an hour that I have during the last 10 years combined.

    15 minutes before the rain started, i had people asking me why I was head to toe in my heaviest raingear. I'm amazed how many people don't know how to access/use a weather radar app or plan ahead for the weather! (Minutes later, when a full on hailstorm was dumping sloppy, quarter sized hailstones, i had several miserable looking people offering cash for my raincoat. Had to pass on the offers - and they were too wet for it to matter anyway :-))

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  19. The storm wasn't accurately predicted by the NWS until 8:55 pm, after it had already begun earlier. It was amazing! I drove thru it, from Edmonds to Lynnwood, during ~ 8:30-8:40 pm. It was scary!

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  20. I measured 0.51" of precip in NW Bellingham between 9PM and 3AM with 0.46" falling between 9PM and midnight. The maximum instantaneous rain rate was 4.92"/hr - one of the highest values I've measured. This type of event, a legitimate thunderstorm, has occurred in this area on only a handful of occasions over the past 15 years. It reminded me of one of the frequent thunderstorms which formed during summer afternoons growing up in the Deep South.

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    1. Jonathan- Thanks for the values. My partner and I were camping in Tomyhoi basin east of you at 5,200 feet and were guessing it rained over 2 inches between 830 and midnight; maybe with the orthographic lift it did.

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  21. We landed in a storm at Paine Field around 9:30 last night. A spectacular show from the air, but all in all, I would have preferred to see the lightning from my living room windows.

    Cliff I'm wondering about your statement that the forecasts were very good. The weather service's forecast at 2:01 pm said "Showers likely and a slight chance of thunderstorms in the evening" (70% chance of precipitation) and their discussion at 1:53 pm said "... we cannot completely rule out a stray thunderstorm developing in the lowlands." Obviously understated relative to what happened. I'm curious: Did other models or forecasts predict the storms, not only in the Cascades, but also in the Puget Sound area?

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  22. Could you imagine living somewhere, where every afternoon/evening during the spring/summer/fall, there was a significant chance of something like this occurring? While it was an amazing show, I could see it getting old very fast (and I love weather). Makes you appreciate our summers even more.

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  23. The forecast models may have been good, but it seems the NWS failed to relay the information to the public. The afternoon forecast package called for a "slim chance" of thunderstorms. (The Discussion focused mainly on the Cascades.) There was no night update. And as far as I can tell, there were no Watches, Warnings, or even Special Weather Statements issued. The only ones I saw were Small Craft Advisories. Seems odd for such an extreme weather event. Perhaps I missed something?

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  24. Never seen so many flashes. I was looking southwest-west-northwest from very high vantage point on Capitol Hill. Looked like hundreds of flashes, wondering if not all hit ground, many only in sky?

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  25. SOMEONE TELL ME WHY the NATIONAL WEATHER SERVICE did NOT issue a SEVERE THUNDERSTORM WARNING? I'm an armchair meteorologist. I was looking at Weather Channel radar and NWS on different devices to see if an alert would be issued. Short term forecast. Period. I lived in Colorado for years. This was a midwest storm. We live up by Lake Goodwin. Virtually constant lightening and crushing thunder for over an hour. The storm was VERY slow moving. Seemed to gather strength the further north it went. Maybe a severe weather warning would have prompted cancellation of the Husky game.

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    1. Severe thunderstorm warnings are issued only if hail is >= 1" in diameter, or if winds exceed 58 mph. Neither criteria was met with last nights storms, therefore no warning. All thunderstorms have lightning, it's the other aspects that classify them as severe/non-severe

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    2. Thank you for your response. Do you think "short term forecast" and the limited information contained in NWS forecast was adequate enough to cover the scope of the storm?

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  26. I have never seen horizontal lighting until last night. What is the story about that?

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  27. Wow, so many comments!

    Cliff, I am so glad you were on top of it especially shortly after your Ocean Shores talk! Impressive indeed. I grew up in this kind of weather, so it didn't bother me. People in that area know the dangers, but it's so common they typically find the sound of thunder comforting. They've grown up falling asleep to it.

    I have empathy for those who aren't accustomed to it and know it can be very disturbing to them. The dangers of lightning are very real. Thanks again for your good work, Cliff!

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  28. Perhaps this was overcautious, but we shut down all our PCs and threw the main breaker at the panel at about 8:30. We have nice electronics that we paid good money for, and I wasn't confident at all in Seattle City Light's ability to tamp down surges.

    We had dinner by candlelight then came back online two hours later.

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  29. Looks like you had the best forecast of this event. NWS was downplaying the threat of tstorms in the lowlands during the day on Sat. Next time, don't keep forecasts of severe weather to yourself.

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  30. I agree that the NWS forecast products—what gets packaged and presented to the public—looked clueless about these storms. And the forecast discussion, a step or two removed, wasn't much better.

    That's especially puzzling since the modeling tools NAILED this thing. Nobody has commented yet on that map showing modeled instability, for example, which is exceptional. Typically, for reasons nobody has ever explained to my satisfaction, the central Sound excels at chewing up convection and spitting it out. (You'd think Beacon Hill in Seattle was the Himalayas, judging from the consistency with which I've seen convection break up in a matter of minutes -- sometimes after having formed on the coast and holding together for hours to get here.)The model said this one would be different, and convection would actually get a shot in the arm as it passed over Seattle—and that's exactly what happened.

    Incidentally, I don't know what the models predicted last night (Thurs. 9/12), but the NWS forecast discussions, even as late as 9 p.m., had nothing useful to say about the line of moderate thunderstorms that passed over Seattle and Bellevue, or the follow-on activity that I saw driving up to Issaquah Highlands. Blowing a forecast is one thing; issuing a forecast discussion that would have been invalidated by looking out of the window is another, and the optics are terrible.

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