We train pilots to avoid thunderstorms: the FAA-approved distance from a storm is 20 miles. For a variety of reasons, that’s not always practical, and we can find ourselves well within 20 miles of a storm, engaged in some bobbing and weaving to avoid what we think are its worst areas. Those generally show red or purple (magenta? violet?) returns on a radar display. But when our weather radar data comes into our cockpit over a datalink, that’s a bad policy.
The main reason is the time it takes to aim a Nexrad antenna at a storm, collect the return data, process it into something visually useful to humans, and then pack and transmit the results to our airborne airplane. All that takes time. During that time, the storm likely has moved.
