Description Vortex/vorticity

Stability - I

Stability - II





                                                  - an overview


Uptill now we were discussing about how is the updrift devoloped.  Along with the updrift the other necessary components needed  for the formation of  a tornado will be discussed now.  For this we need to learn about few terms commonly used to describe the generation of tornado and its structure.

Cold front:

 When an cold (and normally dry) air mass advances into a warmer air-zone and displaces it, the transition zone is called the ‘cold front’. In a weather map a cold-front is shown by a line marked with triangles.

cold front

Warm front:

A warm-front is where warm air is overtaking or displacing cold air. A warm-front is shown by a line marked with semi-circles, in a weather map.

The image “http://ww2010.atmos.uiuc.edu/guides/mtr/af/frnts/wfrnt/gifs/def1.gif” cannot be displayed, because it contains errors.

Stationary front:

It is the zone where cold air meets warm air, but neither of them displaces the other. The symbol for this is practically a  combination of previous two symbols.

The image “http://ww2010.atmos.uiuc.edu/guides/mtr/af/frnts/gifs/sfdef1.gif” cannot be displayed, because it contains errors.

Occluded front:

It is the transition region where cold air overtakes the warm air and lifts it off the ground.

Warm air meets cold air:

warm & cold front

 when cold air and
 warm air meet, the
 moist warm air,
 being lighter,
 rises above the
 cold air.The next
 course of
 incidents depent
 on the
 temperatures of
 the air flows as
 well as on their

 As the rising
 warm  air is
 normally moist, it results in clouds. The situation normally  becomes fevorable for precipitation.
So, at a cold front, where cold air overtakes warm air, the warm air rises rapidly and gets cooled. This can create thunder stormss.

Cold & warm front

In a certain situation cold air is supposed to be on the north and the warm air to the south (see diagram). Then, atmospheric  conditions may develop the associated vortices, in such a way that the transition from cold to warm air takes place in a very narrow area of low pressure. This  continues  until a sudden jump in temperature occurs forming a front.

In the diagram, the shaded portion around the low pressure zone ( marked L),       mrsciguy.com/documents/lab6-6storms.ppt

represents the formation of bands of spiral cloud.


Tapas Bhattacharya
Web-project : Phys-645, Fall-2007, UAF
Animation for 'Home' - taken from www.animationlibrary.com 

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