Plain English Meaning
A nationwide system of powerful ground radars that watch the weather. They show where rain, snow, and storms are, how heavy the precipitation is, and which way the weather is moving. The data ends up in the weather briefings and radar images pilots use before and during flight.
Full Definition
The WSR-88D NEXRAD is the network of high-power, ground-based Doppler weather radars operated jointly by the National Weather Service, the FAA, and the Department of Defense. It detects precipitation, measures its intensity, and tracks the motion of weather systems by sensing the shift of radar reflected from raindrops, snow, , and other particles in the . Its products — including , , storm motion, and weather signatures — are distributed to pilots through , , and products such as the Aviation Weather .