The occurrence of cumulonimbus and nimbostratus together is uncommon, and usually only nimbostratus is found at a warm front.
en.wikipedia.org Open cellular patterns can often be found behind cold fronts in the cold unstable air, and produce multiple cloud types including cumulus congenstus, cumulonimbus, and stratocumulus clouds.
en.wikipedia.org A pyrocumulus which produces lightning is actually a type of cumulonimbus, a thundercloud, and is called pyrocumulonimbus.
en.wikipedia.org Cumulonimbus clouds, commonly called thunderheads, can produce high winds, torrential rain, lightning, gust fronts, waterspouts, funnel clouds, and tornadoes.
en.wikipedia.org The best-known is cumulonimbus with mammatus, but the mamma feature is also seen occasionally with cirrus, cirrocumulus, altocumulus, altostratus, and stratocumulus.
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