In the Spanish dictionary (DLE) consists of the name cumulonimbus, the plural of which is cumulonimbus. It has a masculine gender and is written without any typographic highlight.

The cumulonimbus, according to the DLE, is a ‘dark cloud that forms very high fronts and causes violent storms’. Due to its large size, the cumulonimbus is often said to be the mother of all clouds. Example: A cumulonimbus obscured northern Guayaquil.

The word cumulonimbus is composed of cumulus and nimbus, which in turn come from the Latin words cumlus (joint, union, heap) and nimbus (large, dense, grayish cloud).

Either form of the search can be used, but if the Latin spelling is chosen, it must be written in italics, in quotation marks, or with some other typographical marker. Example: ‘Cumulonimbus’, a cloud that frightened the people of Guayaquil (EL UNIVERSO [Ec.] 3.2.2017).

The names of the winds are written in lower case (austro, levante, monsoon, zephyr, boreas, tramontana, etc.), but they are capitalized when they refer to the mythological character from which they are derived or when they are personified in poetic texts or stories mythological.

High tide, low tide, tide and swell are common nouns, so there is no reason to capitalize them unless the sentence begins with them. (Updated from language corner3-1-2020). (F)

sources:

Pan-Spanish dictionary of doubts (2005), Spelling of the Spanish language (2010) and Spanish dictionary (electronic version), of the Royal Spanish Academy and the Association of Academies of the Spanish Language.