Quite an impressive storm. One thing that I was impressed by was the lower-level moisture. In Taree and Port Macquarie, the pre-storm obs were 23/22 and 24/22, respectively. That results in some seriously low LCL's. The Williamtown sounding shows that the lowest 200 mbar was almost totally saturated. This rich low-level moisture resulted in quite an unstable environment despite the low surface temps. Couple that with 30-40 knot WSW winds at 500 mbar and ~10 knot E/ENE winds in the lowest 100 mbar and you have quite a decent storm setup.