Weather radar just lets you know what’s good or bad out front of you, it’s not like finding something specific. I am assuming that the 60k is 60k above your flight level. So at FL200 you are seeing what’s at 80,000 feet, and there’s nothing to worry about up there except a lack of O2. The cloud to worry about is called a cumulonimbus and it’s top can reach about 40,000 feet. In great big ones they can get a bit over 60,000 feet. The highest I’ve seen was about 55,000 feet on radar as we circumnavigated a hurricane in the south Atlantic while flying weather recon in a C 130.