This 4-panel figure displays radar imagery taken at 4 different radar tilts.  Notice how the higher radar tilts show areas of precipitation where the lower tilts do not (2 examples are circled in yellow).  In this case, radar was detecting precipitation above 8,000 feet which was evaporating below this level.  The lowest radar tilt is detecting precipitation further away from the radar in Kentucky and north central Ohio, but this is because the radar beam reaches about 8,000 feet off the ground that far out.