interesting, in ukrainian "(po)chmura" means "gloomy" and "cloud" will be "chmara".
Polish: pochmurny/zachmurzony -> cloudy (but also gloomy when describes a human)
chmara - large group of animals/humans and especially insects. Wikidictionary says in Ukrainian it corresponds to: рій (similar to rój), зграя (similar to zgraja).
ukrainian uses "рій" to say about large group of insects and "зграя" - about large group of animals; "chmara" can also describes large group of insects, but figuratively.
Any reason why this can't be translated as "THAT cloud is gray?" THAT is suggested as a translation for "Ta," but it is not accepted as a correct response.