Surrey earned a spot in the Royal London Cup playoffs after both their match in Bristol and Sussex's game against Hampshire at the Ageas Bowl were washed out.
The point meant Surrey clinched third spot in the south group ahead of Sussex and Glamorgan and they will now face Yorkshire at Headingley on June 13 with the winner of that match playing Worcestershire at New Road in the semi-finals.
A washout for Somerset at Lord's meant they took second spot in the group and will face Nottinghamshire in the other playoff, the winner of that match facing Essex in the semis.
In Bristol, umpires Jeff Evans and Billy Taylor delayed the abandonment for as long as possible. But there was no let-up in the rain and after a 3pm inspection they decided there was no chance of the ground drying out sufficiently.
That left Surrey hoping that Sussex, the one team with a chance of snatching third place from them, would suffer a similar fate at Southampton at that match was abandoned a short while later.
At Lord's umpires Richard Evans and Rob Bailey called off play at Lord's at 5pm following an afternoon of persistent rain and with a bleak evening forecast.
Middlesex, who had no chance of qualifying, finished eighth in the group with just two wins from their eight matches.