Stratus

Stratus is a low, gray, layered cloud with a nearly uniform base, usually below 2 km, that forms when a shallow moist layer is lifted gently or cooled to saturation, often capped by a temperature inversion. It produces overcast skies, drizzle, and reduced visibility rather than heavy rain. Over the ocean it dominates the marine boundary layer, where the broad decks of stratus and stratocumulus over the cool eastern subtropical oceans reflect sunlight and shape the regional heat budget. Advection of warm moist air over a colder sea surface readily forms marine stratus and the associated sea fog.