in all probability vs likely

in all probability is not an adjective while likely is an adjective.

Word	Noun	Adjective	Verb	Adverb
in all probability	No	No	No	Yes
likely	No	Yes	No	Yes

As adverbs, in all probability and likely are synonyms defined as:

in all probability and likely: with considerable certainty; without much doubt

Other synonyms of in all probability include belike, in all likelihood, probably.

in all probability (adjective)	likely (adjective)
	has a good chance of being the case or of coming about
	within the realm of credibility
	expected to become or be; in prospect

in all probability (adverb)	likely (adverb)
with considerable certainty; without much doubt	with considerable certainty; without much doubt