Saturday afternoon, I was taking a look at my local National Weather Service (NWS) radar feed when I saw a large amount of blue stuff cluttering the radar image.
This ground clutter is scientifically called “Anomalous Propagation” or “AP”, where ground clutter is the easiest type to spot. As a side note; I first discovered the term for AP through a twitter conversation several weeks ago regarding another instance of AP during rush hour on the interstate highway. (If you are interested in weather; a great place to start interacting with the your local weather service is through twitter.)
“Anomalous Propagation (AP) is a false reflectivity echo on radar; an echo that is not precipitation.” This false echo is actually showing smaller objects (dirt, dust and bugs) because the radar is in its most sensitive operation mode and the atmosphere is demonstrating just the right activity to produce those readings.
So, as you get to know the radar of your area and see ground clutter from time to time, rest easy; it is only the natural occurrence of “Anomalous Propagation”. But, beware– AP is also one of the biggest enemies of the modern radar meteorologist.
For more information of Anomalous Propagation and Radar check out these pages:
Screenshot from El Paso NWS Radar on 11OCT14 at 12:45pm