The precipitation-radar images show only qualitative information on precipitation. Their quality is limited to non-quantitative information, since radar is only an indirect method of measuring precipitation, based on reflectivity. Precipitation data in mm and rate data in mm/h are approximations formed via a standard relationship between dBZ levels and instantaneous precipitation values. For different technical reasons radar information is still incomplete and patchy (https://en.wikipedia.org/wiki/Weather_radar).
