northwestern vs northwesterly

northwestern and northwesterly both are adjectives.

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

As adjectives, northwestern and northwesterly are synonyms defined as:

northwestern and northwesterly: situated in or oriented toward the northwest

Other synonyms of northwestern include northwest.

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