forecast vs omen

forecast and omen both are nouns.

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

As verbs, forecast and omen are synonyms defined as:

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

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