The Genesis Of Tornadoes

[knocker]

The genesis of tornadoes is very complicated, and the subject of active research. Vortex2 is a multiyear field project to expand knowledge about the formation of tornadoes. Athough the dynamics of tornadoes are still not fully understood I wondered if a few members, I include myself in this, would appreciate a reasonable simplistic description of the process. It just so happens that Tom Schlatter of Weatherwise fielded a question on the subject in the current Weatherwise which is available online. There is also a neat snippet on funnel clouds. Anyway for what it's worth:

http://www.weatherwi...eries-full.html

[BrickFielder]

It is not a bad description of the tornado genesis mechanisms that you would tend to find in the US plains. There are variations on the themes of horizontal vorticity being uplifted which tend to occur more regularly outside the US plains and its why Florida/California/UK might have more tornadoes per land area than Oklahoma, but of a much weaker variety. For a tornado to exist for any length of time you probably do need a super cell (turning cloud) and conditions for these are best where very warm air meets very cold air like in the US plains. There are other mechanisms by which than can be created, like storm splitting which can occur. Short lived tornadoes can also be created from existing vertical vorticity, like wind eddies around cliffs, thermal eddies due to orographic conditions etc. Another good place to start is ESTOFEX's (European Storm Forecasting Center) research and education link.

http://www.estofex.org/

[Sprites]

That's an interesting site, i read about "dirty thunderstorms" on there a week or so ago, Ive seen a similar diagram to show wind shear in Howard Bluestein's book about supercells.