|| Starpath online classroom || Glossary || Glossary Index || Home ||

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

arcus A dense and horizontal roll-shaped accessory cloud, with more or less tattered edges, situated on the lower front part of the main cloud. When extensive, it gives the appearance of a dark, menacing arch. This accessory cloud occurs with cumulonimbus and, less often, with cumulus. Arcus clouds are often called roll clouds. A sample of arcus is barely discernible in WXT G445. In this one, the roll part is there, but not the arc. In other cases, however, they are very prominent and can arc clear across the sky below a long squall line.

[close window]