When you look at radar velocity, the color is going to represent the direction that these particles are moving in, whether that be towards the radar itself or away from the radar.

It's also when velocity data became available, which shows the change in wind speed and direction. “The difference was, we could see the rotation on the radar," Jeruzal explained.

WRAL meteorologist Mike Moss shows a radar system that tracks the velocity of precipitation falling to the ground.