In a typical Tropical Tidbits GFS map showing 6-hour precipitation rate, is the rate for the six hours AHEAD of the valid time, or for the 6 hours BEFORE the valid time?
E.g., if the map is valid at 12z, is the forecast for 12z-18z, or 6z-12z? (I help to advise on indoor vs. outdoor graduation ceremonies at the college I work at, Bates, and our graduation is Sunday 10am. Looks like showers exiting by 8am or so.) Thanks.