northwesterly vs northwestern

northwesterly and northwestern both are adjectives.

Word	Noun	Adjective	Verb	Adverb
northwesterly	No	Yes	No	No
northwestern	No	Yes	No	No

As adjectives, northwesterly and northwestern are synonyms defined as:

northwesterly and northwestern: situated in or oriented toward the northwest

Other synonyms of northwesterly include northwest.

northwesterly (adjective)	northwestern (adjective)
situated in or oriented toward the northwest	situated in or oriented toward the northwest
coming from the northwest	of a region of the United States generally including Washington, Oregon, Idaho, and sometimes Montana, Wyoming