A weather system building towards parts of south and south-eastern Australia is expected to bring a mixed bag of conditions.The deep low-pressure system brewing below Western Australia is expected to bring rain, storms, strong winds, heat, and then cold temperatures to Victoria, NSW and Tasmania.Weatherzone flagged the system on Monday, predicting it would bring wind gusts of more than 89km/h to Australia's south-east on Friday morning.READ MORE: 'How dare you?': Some of Trump's biggest supporters turn on himPredicted maximum wind