Not much love for the BOM here. The fact is, we don't manufacture the weather. We can control much of the our flying environment, but we can't predict the weather, only offer estimates of what may happen.
However your predictions are getting worse at a alarming rate. This winter has produced numerous diversions and issues that have culminated in this incident.
If you are saying that the BOM cannot forecast properly you need to tell the government this and we need to get CAT III at every capital city airport in Australia and we need to rewrite the regulations in this country. The current situation is untenable and at worst is outright dangerous.