The Qatar 250cc race has been delayed by 40 minutes and shortened to 13 laps due to the surprise weather conditions that have hit the Losail circuit.
The pitlane is now scheduled to open at 21:40 local time, with the race commencing a quarter of an hour later - 40 minutes later than originally scheduled.
Reducing the distance to 13 laps means that 75 per cent distance will still be reached and full points can be awarded.
The schedule change has been forced by the heavy rain that hit just after the start of the 125cc race. That event had to be abandoned after just four laps due to the poor visibility as the floodlights reflected off the surface water and spray.
The race organisers are attempting to ensure that the headlining MotoGP race still starts at 23:00 local time as planned and can run its full distance.