Gorge Wind Blog: 1.5 hours from ecstasy to weirdness.

[windfind]

Hi Gang,

After spending 12 years looking out my window every day down the corridor and driving up and hwy. 84 & 14 watching the wind while recording with a barometer and sailing whenever possible I have some tentative conclusions about some of our wind patterns.

Here is one of those conclusions about the weird wind that sometimes hits the Hatchery and Swell City in the early morning and then again mid afternoon.

I am using yesterday to illustrate how fast the Gorge winds can change but I have seen the same pattern too many times.

http://blog.weatherflow.com/hatchery-heat-wave-winds-am-wind-pm-lose/

Mike Godsey
iwindsurf.com

[windward1]

Yeah, I would not expect many sailors out at 2 A.M.

[scottwerden]

The graphs are labeled July 6, but I assume they are July 4.

One thing that is easy to forget is air motion is a 3-D concept but we talk about it as if everything is 2-D. That works if everything is vertically static, for instance the pressure gradient is the same at the surface as it is at 2000' feet of elevation. My assumption on gusty/swirly wind is that the vertical homogeneity is no longer the case and the wind is moving both vertically and horizontally. When it has a vertical component it is no longer attached to the water. I guess this is what you are saying although I think the air actually becomes turbulent with eddies and swirls from the non-uniform heating of the land adjacent to the river.

I always thought it would be fun to get a source of dense smoke and let it go about 50' above the water mid river and watch what happens to the smoke on a gusty day. They do that in wind tunnels to see what the air flow is doing.

Anyway, interesting stuff.

[windfind]

Hi windward1 & Scott,

Thanks for pointing out the date time issue. I had not used that camera for a long time and its date/time stamp was wrong. I fixed graphic.

The whole point of the discussion of stable air is that there is a 3d component to the air above the river and when there is an inversion the air near the surface has different temperature, density, velocity and even direction than the wind aloft. As I mentioned in the text heating from both the land points and the land/walls along the shore play an issue in the turbulent flow I showed in the graphic.

The critical point is that when the air is stable this heat induced turbulence has much less impact on the quality of the wind.

The smoke idea would fail since the turbulent wind would quickly disperse the smoke. What I actually have used is a bunch of mylar/aluminum film balloons like kid enjoy. While not perfect the are easy to track and give you a very rough vertical wind profile. Releasing such balloons from the top of Angel Island in the Bay Area is how I figured out those days when Berkeley could abruptly die.

Mike Godsey

[isobars]