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Re: The Cause of Tornadoes.

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  • fredwx
    Precipitation releases no heat. Condensation does. The heat is released when wather vapor condenses into cloud droplets and this is the energy that drives the
    Message 1 of 2 , Oct 9, 2002
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      Precipitation releases no heat.

      Condensation does. The heat is released when wather vapor condenses
      into cloud droplets and this is the energy that drives the building
      Cumulus clouds. Precipitation has a net cooling effect as water
      droplets fall from higher colder altitudes to lower warmer altitudes.
      It also drags down cool air by friction - thats why you can feel the
      cool air blast a the beginning of a thunderstorm.


      "Before thunderstorms develop, a change in wind direction and an
      increase in wind speed with increasing height creates an invisible,
      horizontal spinning effect in the lower atmosphere.
      Rising air within the thunderstorm updraft tilts the rotating air
      from horizontal to vertical.
      An area of rotation, 2-6 miles wide, now extends through much of the
      storm. Most strong and violent tornadoes form within this area of
      strong rotation"

      http://www.nssl.noaa.gov/NWSTornado/


      --- In methanehydrateclub@y..., "kirk" <kirk@3...> wrote:
      > Opinions?
      > Kirk
      >
      > http://nov55.com/tor.html
      > The Cause of Tornadoes
      > Tornadoes are caused when a cloud of the right size precipitates
      rapidly
      > releasing heat, which causes it to rise and creates a vacuum under
      it. Air
      > rushing under it creates the vortex.
      >
      > As much as tornadoes have been studied, and as obvious as the
      physics is,
      > the weather predicters still don't have it figured out. Only newly
      forming
      > rain clouds can create tornadoes, yet tornado warnings are always
      given for
      > old clouds.
      >
      > It is known that a sudden drop in air pressure precedes tornadoes.
      The
      > pressure drop is caused by a cloud near the ground rising rapidly
      creating a
      > partial vacuum below it.
      >
      > Precipitation releases as much heat as evaporation absorbs. But
      > precipitation tends to be much faster than evaporation. So a very
      large
      > amount of heat is released when a cloud precipitates.
      >
      > Heat of course causes air to rise. When a cloud near the ground
      rises, it
      > creates a partial vacuum under it.
      >
      > The cloud must be the right size for a tornado to occur. A very
      large cloud
      > would not precipitate uniformly, so the whole cloud would not rise
      at once.
      > A very small cloud would not produce enough precipitation or heat
      to create
      > a large enough vacuum for a tornado to form.
      >
      > Also, the height from the ground would be important, because the
      speed at
      > which the air moves in rushing under it will depend upon the amount
      of space
      > below the cloud.
      >
      > These dynamics only exist during the first few minutes of the
      formation of a
      > heavy cloud. Older clouds precipitate gradually and higher in the
      air, so no
      > vacuum is created.
      >
      > Modern doppler radar substantiates this point. When a tornado is
      reported,
      > doppler radar shows that a new cloud formed out of nowhere where
      the tornado
      > was said to be.
      >
      > Therefore, if people are to be warned in advanced, it has to be for
      an area
      > where clouds are expected to form but have not yet appeared.
      >
      > It might be possible to prevent a cloud from creating a tornado by
      seeding
      > part of it, so it precipitates prematurely and nonuniformly. But
      the time
      > factor would be a problem in locating a newly forming cloud.
      >
      > Cumulous clouds will not create tornadoes, because they dissipate
      energy
      > continuously, and they precipitate too high in the air. A tornado
      cloud has
      > to form rapidly and dissipate its energy all at once. This occurs
      when hot,
      > humid air hits colder air. A typical example is gulf air turning
      north and
      > colliding with other air over Arkansas. In the northern plains,
      clouds
      > usually form more gradually and dissipate energy through cumulous
      > formations.
      >
      >
      > [Non-text portions of this message have been removed]
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