Radar can be a very helpful tool for forecasters, but sometimes it can lead us astray.
Weather radar stations across the country send out radio waves that pick up on targets in the atmosphere.
However, super refraction, sub refraction, ducting, virga and ground clutter are all ways that radar can give us false information.
Subrefraction occurs when a radar beam overshoots and misses the strongest part of a storm, making it appear weaker on radar than it actually is.
The opposite of sub refraction is super-refraction. This is when the radar beam undershoots a storm and bends slightly towards the ground. The beam then picks up on bugs, birds and other objects such as wind turbines, making a storm appear stronger than it actually is. These various interferences are called ground clutter.
Radar ducting is similar to super refraction, but in this case, the beam bends and hits the ground. On radar, it looks like a strong thunderstorm or rain on a clear day when nothing is really there because the ground is thick and sends back a stronger signal than a raindrop.
Virga is when it is raining in higher levels of the atmosphere where the beam hits, but the rain evaporates before it reaches the ground.