Cory Posted January 11, 2011 Share Posted January 11, 2011 Known locally as Taku Winds, these mountain waves occur when cold dense air spills over the Coastal Mountain range and a critical level sets up at the proper altitude to reflect the wave to the surface. The winds crash down Salisbury Ridge right into Gastineau Channel near downtown Juneau and especially impacts the southern end of Douglas Island on the other side of the channel. We're expecting a perfect setup Wednesday morning as we end up with essentially zero flow at 500 mb and should see a strong wave form. 100 mph wind gusts are looking likely with this one, and a few coworkers and I are going to set up near Douglas harbor with handheld Kestrels and a cup anemometer that will be mounted to a Taku version of HurricaneJosh's B.A.S.T.A.R.D weather instrument rooftop mount. FYI, here's an image taken from the Mount Roberts tram just above downtown Juneau (if you've ever been here, it's just above the cruise ship docks). The mountain-wave occurs over the terrain to the left of the pic and the winds crash down into the channel below. You can see the Douglas boat harbor across the channel where we're planning to set up. Here's a view of Salisbury Ridge taken during a Taku event in 2003. You can see a Doppler-On-Wheels truck that was taking part in an NWS/NCAR wind study. Link to comment Share on other sites More sharing options...
beavis1729 Posted January 11, 2011 Share Posted January 11, 2011 Very cool...good stuff. Link to comment Share on other sites More sharing options...
WestMichigan Posted January 11, 2011 Share Posted January 11, 2011 Looking forward to reading about your adventure today Link to comment Share on other sites More sharing options...
daddylonglegs Posted January 11, 2011 Share Posted January 11, 2011 I would imagine the air must warm some as it comes down? Link to comment Share on other sites More sharing options...
patrick7032 Posted January 12, 2011 Share Posted January 12, 2011 I see Cape Spencer had some decent winds....did you get any? Link to comment Share on other sites More sharing options...
patrick7032 Posted January 12, 2011 Share Posted January 12, 2011 I see Cape Spencer had some decent winds....did you get any? Link to comment Share on other sites More sharing options...
turtlehurricane Posted January 12, 2011 Share Posted January 12, 2011 Interesting stuff Cory, good luck! Link to comment Share on other sites More sharing options...
Cory Posted January 12, 2011 Author Share Posted January 12, 2011 One of our mesonet sites just measured a peak wind gust of 69 mph at the Douglas boat harbor. Still looks like the strongest winds will occur 15Z-21Z today and our group will be going down there at about 17Z today. Another interesting event is some ocean-effect snow showers occurring offshore as the strong cold flow moves over the warmer Gulf. Here's a pic of our WFO model forecasting the peak of the event at 18Z (image is sustained wind speed in knots): Link to comment Share on other sites More sharing options...
Cory Posted January 12, 2011 Author Share Posted January 12, 2011 I see Cape Spencer had some decent winds....did you get any? Spencer has a strong local wind effect much of the time. They're well to our east at the entrance to Cross Sound. The winds accelerate through Icy Strait and blast out into the Gulf. Link to comment Share on other sites More sharing options...
Cory Posted January 12, 2011 Author Share Posted January 12, 2011 88 mph gust at the boat harbor...wish I was there already. Link to comment Share on other sites More sharing options...
Cory Posted January 12, 2011 Author Share Posted January 12, 2011 0545 AM NON-TSTM WND DMG JUNEAU 58.30N 134.41W 01/12/2011 AK LAW ENFORCEMENT JUNEAU POLICE DEPARTMENT REPORTED THAT 14 VEHICLES AND 1 HOUSE HAVE HAD WINDWARD-SIDE WINDOWS BROKEN OUT BY THE WIND. THE KTOO RADIO STATION SATELLITE DISH WAS BLOWN OVER. Link to comment Share on other sites More sharing options...
Cory Posted January 14, 2011 Author Share Posted January 14, 2011 I guess I'm sorta blogging to myself here, but I'm thinking we're about to see a Taku event that was even stronger than Wednesday. Other damage that occurred on Wednesday included the lifting of two 1,000 lb steel vault doors at the water treatment plant and all the windows broken out of their work vehicles. The highest measured gust was 88 mph that day, but it's likely there were much higher events since these gusts are isolated (you can watch them descend down the mountain and crash into small areas). I wouldn't be surprised to see a 100 mph + gust today with more damage. I've never seen our WFO model forecast Taku winds as high as it is depicting for today. A plot of vertical velocity at the south Douglas profiler site so far this morning (in the main blast zone), showing the winds headed toward lower levels. Just saw a gust to 70 mph at the surface at the time of the last ob on the right end of the graph. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 14, 2011 Share Posted January 14, 2011 Met-Tech, can you link some good sites to get regional maps? I love mountain weather and mountain waves, but it is hard to comment without seeing maps. Link to comment Share on other sites More sharing options...
Mallow Posted January 14, 2011 Share Posted January 14, 2011 Takus are awesome. I first heard about them at a Pac Northwest Wx Workshop presentation in Seattle a few years ago. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 14, 2011 Share Posted January 14, 2011 Takus are awesome. I first heard about them at a Pac Northwest Wx Workshop presentation in Seattle a few years ago. Stop gloating I am kidding, of course. I personally love mountain weather, so talk of mountain waves, downslope winds, gap flows, gorge/canyon winds, etc. are of great interest to me. In many ways I find mountain meteorology far more exciting and challenging than anything east of the Continental Divide. Link to comment Share on other sites More sharing options...
Mallow Posted January 14, 2011 Share Posted January 14, 2011 Stop gloating I am kidding, of course. I personally love mountain weather, so talk of mountain waves, downslope winds, gap flows, gorge/canyon winds, etc. are of great interest to me. In many ways I find mountain meteorology far more exciting and challenging than anything east of the Continental Divide. Well "Taku" is a specifically SE Alaska event. Not to say that analogous events don't occur elsewhere (indeed, we have had comparable downslope windstorms on rare occasions brought about by essentially the same process), but they're only called Takus in that area. Link to comment Share on other sites More sharing options...
Svrwx Posted January 14, 2011 Share Posted January 14, 2011 Never heard of Takus before. Interesting, please continue posting. Like they say "Learn something new everyday" Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 14, 2011 Share Posted January 14, 2011 Well "Taku" is a specifically SE Alaska event. Not to say that analogous events don't occur elsewhere (indeed, we have had comparable downslope windstorms on rare occasions brought about by essentially the same process), but they're only called Takus in that area. Right, I am not talking about Takus in general but terrain flows overall. Link to comment Share on other sites More sharing options...
Cory Posted January 14, 2011 Author Share Posted January 14, 2011 Met-Tech, can you link some good sites to get regional maps? I love mountain weather and mountain waves, but it is hard to comment without seeing maps. Some surface and upper-air maps here: http://aawu.arh.noaa...raphical_fa.php http://aawu.arh.noaa.../upperwinds.php Also check out the real-time JAWS wind sensors/profilers around Juneau that were set up by the FAA to watch for these types of things. In the early 90s, an Alaska Airlines 737 with 100 people on board nearly inverted and narrowly escaped crashing (recovered a few hundred feet off the ground) due to a different mountain wave that occurs in rare conditions near the airport here. http://jaws01.net/ Vertical velocity images from the profilers: http://pajk.arh.noaa.gov/profVV.php Takus are awesome. I first heard about them at a Pac Northwest Wx Workshop presentation in Seattle a few years ago. Carl Dierking (our SOO), and Brad Colman wrote the first papers on them back when Brad was up here. Carl has done a couple of other studies, including discovering the mountain wave processes near the airport that I mentioned above. Takus are fascinating...I did a poster presentation last year in Fairbanks on a modeling study that tested various WRF configurations for the ability to forecast the Taku impacts in the very narrow Gastineau Channel between downtown and Douglas Island.The model works very well for that, with surprising detail when considering how small of an area is impacted. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 14, 2011 Share Posted January 14, 2011 Some surface and upper-air maps here: http://aawu.arh.noaa...raphical_fa.php http://aawu.arh.noaa.../upperwinds.php Also check out the real-time JAWS wind sensors/profilers around Juneau that were set up by the FAA to watch for these types of things. In the early 90s, an Alaska Airlines 737 with 100 people on board nearly inverted and narrowly escaped crashing (recovered a few hundred feet off the ground) due to a different mountain wave that occurs in rare conditions near the airport here. http://jaws01.net/ Vertical velocity images from the profilers: http://pajk.arh.noaa.gov/profVV.php Carl Dierking (our SOO), and Brad Colman wrote the first papers on them back when Brad was up here. Carl has done a couple of other studies, including discovering the mountain wave processes near the airport that I mentioned above. Takus are fascinating...I did a poster presentation last year in Fairbanks on a modeling study that tested various WRF configurations for the ability to forecast the Taku impacts in the very narrow Gastineau Channel between downtown and Douglas Island.The model works very well for that, with surprising detail when considering how small of an area is impacted. Thanks for the maps, I will give them a look over. WRT the models, how do they do with probabilities? I need to do more reading up on the mechanisms, but there have been a couple studies on ensemble modeling with high-res models trying to simulate wave-breaking and/or trapping potential with extreme downslope windstorms in Boulder--and they were generally a fail outside of 12 hours (probability wise). In other words, it was difficult to fully know if a true major downslope windstorm would occur either do to upper level wave-breaking or inversion trapping. Link to comment Share on other sites More sharing options...
Cory Posted January 14, 2011 Author Share Posted January 14, 2011 The BASTARD II attached to my car on Wednesday (south Douglas profiler in the background). This model can switch between using the Kestrel vane mount and this cup anemometer. We got there during a relative lull in the winds and only recorded a peak gust of 45 mph. I'm going back down there today. Link to comment Share on other sites More sharing options...
Cory Posted January 14, 2011 Author Share Posted January 14, 2011 Caught this 65 mph gust on video. I spent 2 hours at Douglas Harbor and had three gusts in the 65-70 mph range, with many 50-60 mph. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted January 14, 2011 Share Posted January 14, 2011 Caught this 65 mph gust on video. I spent 2 hours at Douglas Harbor and had three gusts in the 65-70 mph range, with many 50-60 mph. That was amazing, great vid Met Tech. Link to comment Share on other sites More sharing options...
Srain Posted January 14, 2011 Share Posted January 14, 2011 Pretty neat, Cory. Link to comment Share on other sites More sharing options...
k*** Posted January 14, 2011 Share Posted January 14, 2011 awesome video, cory Link to comment Share on other sites More sharing options...
turtlehurricane Posted January 14, 2011 Share Posted January 14, 2011 That's friggin awesome! Link to comment Share on other sites More sharing options...
Mallow Posted January 15, 2011 Share Posted January 15, 2011 Caught this 65 mph gust on video. I spent 2 hours at Douglas Harbor and had three gusts in the 65-70 mph range, with many 50-60 mph. Psshhh. I'll have to bring a camera next time I go up to Crown Point during a Gorge event. They happen several times a winter, and due to the specific topographic setting and a concrete building being situated on the bluff, gusts get to 90+mph, I would estimate, as they whip around the building. Or maybe you can send me a BASTARD rig so I can measure it! I base my estimations on the fact that you get knocked over while bracing yourself at times, and it's impossible to make headway during the gusts. Try to take a step forward and you'll end up further back. It's awesome! Link to comment Share on other sites More sharing options...
bowtie` Posted January 15, 2011 Share Posted January 15, 2011 Cool stuff MetTech. If Josh sees this will he be jealous? Link to comment Share on other sites More sharing options...
Cory Posted January 15, 2011 Author Share Posted January 15, 2011 Thanks, guys. Psshhh. I'll have to bring a camera next time I go up to Crown Point during a Gorge event. They happen several times a winter, and due to the specific topographic setting and a concrete building being situated on the bluff, gusts get to 90+mph, I would estimate, as they whip around the building. Or maybe you can send me a BASTARD rig so I can measure it! I base my estimations on the fact that you get knocked over while bracing yourself at times, and it's impossible to make headway during the gusts. Try to take a step forward and you'll end up further back. It's awesome! Nice! That would be some cool footage. Maybe you do need a BASTARD rig. Cool stuff MetTech. If Josh sees this will he be jealous? I doubt it. He'd consider this to be icepu**y nonsense. Link to comment Share on other sites More sharing options...
Mallow Posted January 16, 2011 Share Posted January 16, 2011 Nice! That would be some cool footage. Maybe you do need a BASTARD rig. I doubt it. He'd consider this to be icepu**y nonsense. Yep. Link to comment Share on other sites More sharing options...
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