The "age indicator" on some in-cockpit weather displays can show a time stamp that's off by as much as 20 minutes, the NTSB warned in a safety alert issued on Wednesday. "Even small time differences between the age indicator and actual conditions can be important for safety of flight," the safety alert (PDF) says, "especially when considering fast-moving weather hazards, quickly developing weather scenarios, and/or fast-moving aircraft." The NEXRAD "age-indicator" on the cockpit display indicates the time the mosaic image was created, not the time of the actual weather conditions. The NEXRAD image is always older than the actual weather conditions, the NTSB said.
This is a companion discussion topic for the original entry at https://www.avweb.com/news/ntsb-warns-pilots-weather-radar-can-be-misleading