The agencies were correct about the information, however unlike OP apparently I know how to adjust for time zone differences. Monday morning in Australia is still Sunday in the US, so yes that would have been the correct time for the warning. But this article was posted here a day after the event occurred, all of the warnings expired, and the Kp index had dropped back down to more moderate levels. At the peak of the event the Kp index reached around 8.0. When I posted my comment yesterday it was sitting at 1.66, well below the threshold for seeing auroras anywhere in the continental US. If you had any chance of seeing auroras here it would have had to be Sunday night, not Monday night.