Just going by the past few events and the weather isn't going to help the Auction catalogue is usually out between 3 and 7 days before the event.
For example the last Harpy it came out on the 19th September for the 22nd September event.
RWB on the 8th Dec catalogue came out on the 1st Dec
It's a lot of work for Mike and the crew, so I try to make my travel decision not based on the auction alone
Cheers
Mike T