Tell you what Backhoe, no matter what happened to the weather, how great to see a Boatie who pays so much attention to the weather and makes an effort to understand it, lives with it, makes allowances and then does some research to see what the problems may have been. With that attitude Mate, you are one of the true professional Boaties out there who will hopefullynever get into trouble. First of all, SEABREEZE and BUOYWEATHER do NOT use Australian BOM data but instead use OFFSHORE models as they say i.e. probably out of the USA somewhere! They both advised this to me directly by email and I posted it here somewhere a week or so ago. Not saying they are not very professional organizations, they have great web pages and some excellent educational and informative stuff for Boaties so don't discount them by any means. Always a good double check!
Just remember that the weather source is NOT necessarily where the real weather is!
I'm too lazy to check out the individual weather reports you mentioned but I would respectively suggest that you stick to the Marine Boating forecast all the time. BOM most probably have different parameters for updating a forecast. For example, if there is a temperature change of say five degrees on the marine forecast anticipated, then maybe that demands them to crank out a new forecast ....... I guess I could find this out for you guys......geeeez, work, work, work................!
Another thing to remember, that the weather system causing the SE is about 4000 x 2000 kilometres in size being 8000 square kilometres overall. Pretty big and and it only takes the most minor hiccup of temp/wind/Baro changes (plus lots more) to slow down or speed up the weather. Your 2.5 hour example in the weather industry would be viewed by most #to be highly accurate . Bit of a bumma at the Pin I know but your little patch of water down there is only a couple of hundred square metres - kinda small when viewed to the 8000 K's above eh! In one of my legendary and much sought after weather courses I post here , I intend next week to concentrate on this aspect of why weather forecasts go wrong (15% of the time usually)
Keep up the great work on asking "why" when it comes to weather. Top stuff! #