A word for “cloud” appearing in the plural form lumbor “clouds” in the Markirya poem of the 1960s. An identical form ᴱQ. lumbo appeared five decades earlier in the Qenya Lexicon of the 1910s with the gloss “dark lowering cloud” as a derivative of the early root ᴱ√LUVU (QL/57). The context of the 1960s Markirya poem was that of a gathering storm, so it seems likely lumbor also referred to dark or stormy clouds. As further support of this, in other late notes lumbo was glossed “gloom” (PE17/72) or “dark, shade” (PE17/168) as a derivative of √LUM or √LUB “shadow, darkness”.
Neo-Quenya: For purposes of Neo-Quenya, I would assume lumbo mainly means “dark cloud”, along with the general darkness and gloom of bad weather.
lumbo noun "cloud" (pl. lumbor in Markirya), also glossed "gloom; dark, shade" (PE17:72, 168). In early "Qenya", lumbo was glossed "dark lowering cloud" (LT1:259)