Out Of Nowhere Meaning

(idiomatic) In an unexpected or inexplicable manner of arrival or occurrence.

Example: 1906, Jack London, "Brown Wolf,"
  It had been no easy matter when he first drifted in mysteriously out of nowhere to their little mountain cottage.
1916, P. G. Wodehouse, Uneasy Money, ch. 12,
  Mr Pickering's 'Hi!' came out of nowhere and hit him like a torpedo.
2015 May 25, Daniel Taylor, “Norwich reach Premier League after early blitz sees off Middlesbrough”[1], The Guardian (London):
  The opening goal came out of nowhere and, buoyed, it was a lovely sequence of crisp passes that culminated in Steven Whittaker playing in Nathan Redmond to double the lead.