Which cloud type is described as forerunners of fronts?

• A. Cirrus
• B. Cumulus
• C. Lenticular
• D. Altocumulus

Answer: (A)

Cirrus clouds are high, thin, ice-crystal clouds that often appear ahead of an approaching front. Their presence signals moisture rising into the upper atmosphere and lifting in advance of a disturbance, so you typically see them hours to a day before any precipitation reaches you. This makes cirrus the classic forerunner of fronts, giving a heads-up of changing weather to come.

Cumulus clouds are associated with daytime convection and surface heating, not with fronts per se, so they don’t serve as reliable indicators of an approaching front. Lenticular clouds form in mountain waves and are tied to orographic effects rather than frontal systems. Altocumulus are mid-level clouds that can indicate instability, but they don’t consistently signal an approaching front as clearly or as early as cirrus do.