omen vs forecast

omen and forecast both are nouns.

Word	Noun	Adjective	Verb	Adverb
omen	Yes	No	Yes	No
forecast	Yes	No	Yes	No

As verbs, omen and forecast are synonyms defined as:

omen (noun)	forecast (noun)
a sign of something about to happen	a prediction about how something (as the weather) will develop

omen (verb)	forecast (verb)
indicate, as with a sign or an omen	judge to be probable
	predict in advance
	indicate, as with a sign or an omen