FPSC Referee Coordinator
What to Do in Case of Thunder & Lightning.
From the USSF "Advice to Referees."
USSF Advice to Referees 5.11 is your authority. USSF announced by memorandum several years ago that they would follow the then so-called 30-30 rule in determining when to suspend a match for lightning; i.e., when lightning is observed, if the thunderclap is heard in less than 30 seconds then the source is close enough to be a danger and the match should be suspended for at least 30 minutes past the last lightning strike.
If you suspend the match and it looks like the storm will pass, you can resume the game. However, if there is another lightning strike, then 30 more minutes! Keep in mind the following for games. Either play shorter halves or cancel the game so the follow-on teams can play on time.