BUFFALO, N.Y. (WKBW) — As severe thunderstorms crossed northern Ohio Wednesday evening, I took some time to talk about how meteorologists use radar when looking for tornadic activity.
Of course, everyone can look at a radar screen and see rain and even thunderstorms if lightning is on their app but to an untrained eye, it mainly looks like a blob of various colors. You also might know that the darker the orange or deeper red is heavier rain while the lighter yellow and green are lighter showers.
What you probably don't realize is the shape of those colors means different things too and there are different tools and parameters meteorologists can use to understand what's going on!
I'm specifically talking about Doppler Radar Velocity in this article and the signature a potential tornado makes on it.
When a Doppler radar is in velocity mode you see two colors, red and green. Red means something is moving away from the radar and green means something is moving towards a radar. When you see red wrapped in green like in the video above that is called a TVS, a Tornado Vortex Signature. A TVS is a very tightly concentrated area of rotation (high above the ground, several kilometers) hence you have a small area with green and red wrapped together (movement towards and away from the radar). And while this doesn't indicate that there is a tornado on the ground it strongly suggests one can form.
In the video, the Tornado Warning from the National Weather Service uses the wording of a confirmed Tornado on the ground. This can only happen when a tornado is visibly seen by a person. A Doppler Radar can only use the wording "Doppler indicated" until a visual is confirmed.
