This next one is from Namoi on April 6 2011. It was it was visible from 9:20 to 12:30 EST on the national and NSW/ACT composites. Prior to that, beginning from 5:10 EST, according to the national radar every station in the country was offline for 3 hours 30 minutes.
Then the following day:
Here’s what one of the Weatherzone forum contributors had to say about that Darwin show:
Whats more interesting is I was up in Darwin during that period. On the 26th I did notice ripple clouds. Well thats what I call them anyway. Its like lines rippling out. I’ve seen them around SEQ on clear days before the weather takes a turn for the worse. That particular day in Darwin they just grew together and made it overcast.