and there are plenty of unusual weather events corresponding to these anomolies!
That is not unusual, nor incredible weather for Melbourne.
Melbourne lies at the shore of Hobson's Bay and has the Yarra River running right through town.
It has a moderately oceanic climate and is prone to strong cold fronts in the summer which can rapidly intensify the convective activity there (a lake effect intensification) and large hail and heavy rain is typical in the summer...
No weather manipulation is necessary to produce what you see in Melbourne, save the weather modification that nature produces all by herself.