<Li> Genus cirrus (Ci): </Li> <Dl> <Dd> These are mostly fibrous wisps of delicate white cirriform ice crystal cloud that show up clearly against the blue sky . Cirrus are generally non-convective except castellanus and floccus subtypes which show limited convection . They often form along a high altitude jetstream and at the very leading edge of a frontal or low - pressure disturbance where they may merge into cirrostratus . These high clouds do not produce precipitation . </Dd> </Dl> <Dd> These are mostly fibrous wisps of delicate white cirriform ice crystal cloud that show up clearly against the blue sky . Cirrus are generally non-convective except castellanus and floccus subtypes which show limited convection . They often form along a high altitude jetstream and at the very leading edge of a frontal or low - pressure disturbance where they may merge into cirrostratus . These high clouds do not produce precipitation . </Dd> <Ul> <Li> Genus cirrocumulus (Cc): </Li> </Ul>

Chemical and physical processes include the formation of clouds