On Mar 7, 10:47*am, wrote:
There are millions of people who live in the Tornado belt. *I want to
buy a Tornado warning device for my home. The National Weather service
delights in waking me up in the middle of the night if Tornado
conditions occur in the neighboring State. I want to install a device
on the roof of my house that listens for the characteristic sound of a
Tornado approaching on the ground.

Think about this problem because the solution could make you rich.

Somebody apparently already has and invented something called "doppler
radar". "Doppler radar can tell when a thunderstorm has Tornado
Vortex Signature (TVS)" I doubt you could afford one, but you may be
able to make one of your own.

"While the NWS radars and some radars operated by television stations
have Doppler capability to show wind direction and speed, the images
are extremely complex and are much more difficult to understand than
reflectivity images. (Related: Doppler radar)" Hook echo's "... are
commonly found in a single thunderstorm, in which the reflectivity
image resembles a hook. When this occurs, the thunderstorm is
producing a circulation and possibly a tornado. The rain gets wrapped
around this circulation in the shape of a hook.

-- http://usatoday30.usatoday.com/weather/wearadar.htm