Tornado Observations

  • When there is a good chance of tornadic formation within the next few hours, a tornado watch is issued by the Storm Prediction Center in Norman, Oklahoma (
  • When a tornado has been spotted by:
    • trained spotter
    • on radar

    then a tornado warning is issued

Observation with a radar:

  • We now have a national network of radars called the Weather Surveillance Radar (WSR-88D) that can observe tornadic storms
  • recall that the tornado forms from the mesocyclone at low levels.
  • the mesocyclone can be observed with a radar and is called a "hook echo"
  • Here is another example of a hook echo
  • Important!!!: the radar can not see the tornado itself since the scale of the tornadic circulation is very small (on average 100 m wide).
  • The radar can see the mesocyclone which is 2-4 km wide.