In literature the term “thundercloud” is often employed as a color metaphor to evoke moods of gloom, foreboding, or anger. Authors compare a character’s appearance to the heavy, dark hues of a stormy sky—for example, a face or brow described as “black as a thundercloud” ([1], [2], [3], [4], [5]) immediately signals a brooding or irate temperament. At the same time, the word’s association with clouds lends itself to subtle variations in tone, such as when a new object is likened to a “lovely dove-grey—like a thundercloud” ([6]), or when a landscape’s dramatic transformation is underscored by “a leaden background of thundercloud” ([7]). In each instance, the color imagery not only paints a picture of literal darkness or pallor but also deepens the emotional and atmospheric layers within the narrative.