Non-Severe ThunderstormThe following section gives a general overview of the important physical principles that we will consider as we explore the development of thunderstorms. Topics which we will address will include buoyancy, drag, shear, and vorticity.
As bubbles of
air become heated near the earth's surface they become buoyant and rise
in the atmosphere. White puffy cumulus clouds can be the product of these
rising air bubbles. If the atmosphere is unstable enough (that is,
these bubbles can easily continue to rise) these clouds can become thunderstorms.
Thunderstorms (storms which produce lightning and thus thunder) will be
the main topic of our discussion.
Distinctions
will be made between different types of thunderstorms which occur in our
atmosphere. For example, in non-severe thunderstorms the precipitation
produces drag on the atmosphere and causes air to flow downward on top
of the updraft. This quenches the updraft and the system dies. On the other
hand, if the downdraft is tilted to the side of the updraft the circumstances
are changed dramatically and the storm may become severe.
This situation is caused both by speed shear (wind speeds change with height
in the atmosphere, usually they increase) and directional shear (change
of wind direction with height in the atmosphere). We will see how these
two factors can interact with the cloud updraft to transform a severe storm
into a violently rotating column of air which we know as a tornado.
The main ingredients
involved in these process will be demonstrated by animations and pictures.
These are intended to give storm spotters better understandings of the
processes that occur inside a thunderstorm. So get involved and
explore the amazing systems produced in our atmosphere.
Non-Severe Thunderstorm