prevailing westerly vs westerly

prevailing westerly and westerly both are nouns.

Word	Noun	Adjective	Verb	Adverb
prevailing westerly	Yes	No	No	No
westerly	Yes	Yes	No	Yes

As nouns, prevailing westerly and westerly are synonyms defined as:

prevailing westerly and westerly: the winds from the west that occur in the temperate zones of the Earth

prevailing westerly (noun)	westerly (noun)
the winds from the west that occur in the temperate zones of the Earth	the winds from the west that occur in the temperate zones of the Earth

prevailing westerly (adjective)	westerly (adjective)
	of wind; from the west
	moving toward the west

prevailing westerly (adverb)	westerly (adverb)
	in a westward direction
	from the west