First Alert Weather In Depth: The truth about radar

ROCHESTER, N.Y. – We are always talking about the News10NBC weather app and the obvious benefits. Recently, someone asked specifically about the radar and mentioned that the radar showed rain near their house, yet there was no precipitation when looking outside their window. So what is going on here?

This is a meteorological phenomenon called “Verga.” Verga is a Latin word for “branch” or “rod.” It appears to the human eye to be a streak or curtain located in the distant sky. In this case the precipitation is falling from the cloud, but in reality it is evaporating before reaching the ground.

The News10NBC First Alert Doppler is a wonderful instrument, but it’s far from being a perfect forecast tool. A radar produces a signal or a pulse of energy that is send out over a great distance and energy is looking for precipitation. However, it is the composition of the atmosphere that is a determining factor of what the radar will actual see. In this case, the precipitation is falling into a dry portion of the atmosphere. 

As a result of that dry air, the rain or snow can evaporate before reaching the ground. The radar will see that precipitation, but the cloudburst is not reaching you at the surface of the Earth. Eventually that moisture will reach the entire column of the atmosphere and sooner or later you will need the umbrella. No doubt the radar is not perfect and most folks would say neither is the meteorologist.