The Australian IPS has issued a geomagnetic alert for possible minor storms on July the 19th due to the impending impact of a coronal mass ejection.
GEOMAGNETIC ACTIVITY FORECAST
18 Jul: Unsettled to Active
19 Jul: Active with Minor Storm periods
20 Jul: Quiet to Unsettled
High latitudes (Tasmania, Southern New Zealand, Australian Antarctic Territories) should be on the lookout tomorrow and the day after (Friday 19 and possibly Saturday 20th). Although high latitudes are the best bet, the last two auroral shows were seen in Victoria and WA, so keep an eye peeled. Aurora can strike any time, look to the south for unusual glows, shifting glows or pillars of light. Some idea of the sorts of things it might be possible to see is http://astroblogger.blogspot.com.au/2013/07/images-from-saturday-nights-aurora.html
However, the waxing moon will significantly interfere with seeing any aurora in the evening, and dark sky sites have the best chance of seeing anything. The weather is not entirely favourable either.
If you are up on Saturday morning aurora watching, why not wave at Saturn