A big storm is forecast to hit Australia by Christmas.
A weather bureau report warns a low pressure system is moving towards the west, with temperatures expected to climb into the 90s.
But there is concern the system could also bring rain.
The Bureau of Meteorology said it had received a warning for up to three days and was concerned a low on Wednesday could bring rain to the west.
It warned heavy rain was possible in the Perth area, with a peak of 15mm possible.
The bureau said it was also worried by heavy rain to come, with the potential for rain showers to arrive at the weekend.
It said there could be some isolated flash flooding conditions for up a couple of days and it was likely the situation would worsen as the system continued.