Abstract: Methods and apparatus are provided for operating a radar system to provide a thunderstorm image to a pilot. The method comprises using one or more radar scans depending upon the aircraft altitude, a single upward tilted scan at or below a datum level of about 15,000±3000 feet wherein a clutter free storm image may be obtained and two scans above the datum level; a first upward tilting scan to determine, clutter free, a storm head perimeter and a second lower tilting scan for the storm body with ground clutter. The perimeter is used to discard return echoes from the second scan that lie outside the perimeter or an expansion thereof and retain those lying on or within the perimeter. The result is presented to the pilot. Optionally, the thunderstorm image is graded from center to edge so as to indicate weaker echo intensity near the edge.