Thus I might use it in an email to a friend; but not e.g. in an official letter about the results of an autopsy. It seems good enough for some of those who cover Forex:

Hello Amit, 1. We will inform you post-weekend. There can be no objection to this in terms of word-formation: the prefix "post-" modifies "weekend", with the meaning "after the weekend", and "post-weekend" itself acts as an adverb.