jetstream gravity waves and turbulence

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danlj

Posted: Wed Mar 07, 2007 6:35 pm

Guest

An acquaintance recently encountered severe turbulence at about 20,000
feet over eastern North Carolina after flying in westerly cross-winds
of up to 150 kt.

Due to the SW direction of the wind, he believes that this was not
mountain lee wave; I suspect it was related to the jet.

I am a simple rural physician, with good science training but an
unsophisticated knowledge of meterology and no ability to appreciate
the nuance of numerical models.

I would like to learn about how to recognize the potential for such
turbulence and avoid it, using the meteorolgy resources available on
the www. Who may I contact? What could I read?

Thanks,

DJ

Ron Hardin

Posted: Wed Mar 07, 2007 7:19 pm

Guest

I would imagine, from a physics point of view, the gravity wave doesn't
matter, and it's more a question of an unstable wind shear with or
without a density change to support a gravity wave.

I think stability of a wind shear depends on the something obscure
like having no zero of the third derivative of the shear profile.

Once it's unstable, it breaks up into turbulence, with larger
scales in turn breaking up and going to shorter scales, until
eventually it cascades down into heat. That's the stuff you want
to stay out of, if a large shear velocity is involved.

On the other hand, a density change across a wind shear, I have always
suspected, gives nice you herring bone clouds across the sky, where the
fastest growing unstable mode selects out the wavelength. I don't think
they're particularly turbulent.
--
Ron Hardin
rhhardin@mindspring.com

On the internet, nobody knows you're a jerk.

Weatherlawyer

Posted: Thu Mar 08, 2007 4:21 pm

Guest

On Mar 7, 10:35 pm, "danlj" <dLeR...@gmail.com> wrote:

Quote:

Someone else has taken this over but it is still worth a visit:
http://www.booty.org.uk/booty.weather/uswfaqfr.htm

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