Which weather phenomenon typically indicates an upcoming change in the weather?

Cumulonimbus clouds are significant indicators of upcoming changes in weather due to their association with severe weather conditions. These towering clouds can develop rapidly and are often linked to thunderstorms, heavy rainfall, lightning, and even tornadoes. As they grow vertically, they can signal the approach of unstable air, which typically leads to sudden shifts in weather patterns. Their presence often means that atmospheric conditions are conducive to more intense weather phenomena, so when you see these clouds forming, it’s wise to anticipate a change in the weather.

In contrast, the other types of clouds mentioned do not indicate imminent severe weather changes. Cumulus clouds can suggest fair weather or slight changes but are generally harmless. Cirrostratus clouds indicate moisture at high altitudes and can foreshadow precipitation, though they do not imply the intensity of weather changes like cumulonimbus. Stratocumulus clouds are typically stable and often found in fair weather conditions, indicating little change in the weather pattern. Thus, cumulonimbus clouds stand out as clear indicators of significant weather changes on the horizon.