Radar for Meteorology Students

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Here's a little tip that can be used when interpreting radar images, especially in winter when stratiform rain and snow have lower cloud tops than in summer. 

What does this radar image show?
When a radar echo has a circular edge, it is nearly certain the precipitation extends farther in that direction than the radar depicts. Why?

The reason is that the radar overshoots the rain or snow. 
This illustration is a simplification in that the radar beam curves 
at a much lesser rate than the earth's curvature. 
The overshooting results in a circular edge to the radar echo.

And, when the circular shape is between the radar and the precipitation, it means the precipitation is not reaching the ground. 

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