Radar tip. When cruising at high altitude IMC/night ensure the radar gain control is set at MAX position rather than AUTO or CAL.
It gives you a better chance to pick up weak reflections from the dry area in the CB anvil which will not normally paint on radar in auto gain. Under these conditions even the tiniest echo picked up on MAX gain is indicative of a towering CB top well above your cruise altitude. Read the Pilot's Guide handbooks which each radar manufacturer publishes. See your local radar manufacturer's agent in most capital cities.