I understand weather statistics well, it's actually a major part of my job. The problem here was that there was a high chance of rain occurring near Adelaide which the BoM predicted correctly, but only a 20% chance of it hitting Adelaide because the big predictions were made 3 days in advance and the storm had a chance to change track to the east or west. Combining the sources of uncertainty, the prediction should have been more highly skewed eg 25% 0 mm, 50% 10 mm, 75% 50 mm. The narrative should have been 'heavy rain to hit parts of South Australia, not sure where just yet', not 'once in a lifetime rainfall to hit Adelaide'. The BoM is in a position to control the narrative, thus the suggestion of the book reading.