Overshooting top locations appear as colored squares in Google Earth.

The magnitude of each overshooting top (the difference between the "anvil" temperature
and the "overshooting top" temperature) are colorcoded according to this scale:
mag >-11C: red
-13C < mag <= -11C: orange  
-15C < mag <= -13C: yellow
-17C < mag <= -15C: green
-19C < mag <= -17C: blue
-21C < mag <= -19C: purple
-23C < mag <= -21C: black
mag < -23C: white

Please note: this algorithm does not include the tropopause temperature, but 
overshooting tops must be colder than 215K.