Plain English Meaning

NEXRAD radar pictures of weather are not perfect. They can miss things, show false returns, and are always a few minutes behind real time. Pilots need to know what NEXRAD gets wrong so they don't trust it for close-in decisions about thunderstorms.

Full Definition

Known limitations and inaccuracies in the radar imagery produced by the Next Generation Weather Radar (NEXRAD) system. These include ground clutter, range attenuation (weakening of the radar beam over distance), the cone of silence directly above each radar site, false echoes from terrain or non-weather objects, and the time delay between when the radar scans the weather and when the image reaches the cockpit. NEXRAD imagery shown on a Multi-Function Display (MFD) can be several minutes old, even though the timestamp may suggest otherwise.