Why does the National Weather Service need spotter reports?
While the National Weather Service has the latest technology in the form of Doppler Radar, they need trained spotters in order to confirm that what is being shown on radar is what is indeed happening on the ground in the affected area. Doppler radar can detect what’s known as a “hook echo” which is a hook-shaped reading on the radar to indicate rotation in a certain cell, or Cumulonimbus Cloud. Click here to see what a “hook echo” looks like. This was taken by Doppler Radar in May of 2002 from an F5 Tornado that tore through Maryland. But what the Doppler radar cannot do is determine whether or not that rotation is on the ground as a tornado, or if it is a funnel cloud, or even a false echo. Trained spotters in the affected area can confirm or deny what the radar is showing. That is why East Tennessee SKYWARN is so valuable to the National Weather Service.
