Hot weather in Perth is expected to be followed by storm clouds and the chance of thunderstorms this afternoon and tomorrow.
The city is expected to reach a top of 35C with sunny conditions in the morning and isolated showers and storms in the afternoon and evening.
Weather Bureau duty forecaster Peter Clegg said the hot conditions were caused by a heat trough developing on the west coast.
"Essentially that's just bringing very warm conditions from the northern inland parts," he said. "Along with that we've got a far amount of instability coming through in the upper level as well, generally unsettled conditions which is leading to the chance of a storm."
Mr Clegg said there were already thunderstorms near Geraldton and the instability was expected to move south today, with the chance of storms in Perth through until tomorrow morning.
He said any storms were not expected to bring dangerous winds gusts or conditions requiring a severe weather warning.