Altostratus cloud size again. During the sampling of one cloud, the scientists noted a halo while flying near the top of the cloud, which indicated that the ice crystals were hexagonal near the top. However, farther down, the ice crystals became more conglomerated. Altostratus tends to form ahead of a warm or occluded front, the altostratus gradually thickening into rain bearing nimbostratus. However it can also occur together with cumulus congestus or cumulonimbus at a cold front. "Velum" This is considered a type of cumulonimbus cloud so it is not listed. Altostratus cloud Altostratus is a middle altitude cloud genus belonging to
Stratocumulus cloud with two or more layers or sheets. Stratocumulus duplicatus is common on species lenticularis or lenticular cloud. Stratocumulus Lacunosus clouds are very uncommon. They only occur when there are localized downdrafts striking through the stratocumuliform cloud. Stratocumulus Mamma is a type of mammatus cloud. Stratocumulus Virga is a form of precipitation that evaporates in mid-air and doesn't reach the ground. Stratocumulus Praecipitatio is a form of precipitation that reaches the ground as light rain or snow. Stratocumulus Cumulomutatus the specific type of stratocumulus clouds, are flat and elongated. They form in the evening, when updrafts caused by convection decrease making