Interesting word. To discover beforehand probably means in regard to an event - to discover it before it occurs. Here is one example of it in context as searched out by Google
... "the inability of the government to prediscover such riots as, Lagos (OPC), Kaduna, Shagamu, etc, etc and nip them in the bud."
Nzeribe moves to impeach Obasanjo - The Vanguard
The other instances found in Google made little sense to me and were mostly porn sites. Something about prediscovering beautiful babes ...