In each case, something is being foreshadowed or forecast. Fore is an Old English prefix that means "before" or "earlier," and it's combined here with tell, "to reckon or consider."

Is foretell a prefix?

a prefix meaning “before” (in space, time, condition, etc.), “front,” “superior,” etc.: forehead; forecastle; forecast; foretell; foreman.

What does a foretell mean?

foretell, predict, forecast, prophesy, prognosticate mean to tell beforehand. foretell applies to the telling of the coming of a future event by any procedure or any source of information.