Southwestern parts of Western Australia received a drenching overnight, with some places seeing their heaviest rain in years. A low pressure system just south of the state and an associated trough brought rain and isolated thunderstorms to the region from Wednesday afternoon and into this morning. The South West copped the heaviest rainfall, with widespread falls of 30-50mm to 9am this morning. Pemberton picked up 50mm, its heaviest rain in four and a half years, and the heaviest for May in eight years. Busselton and Manjimup also saw their heaviest May rain in eight years, picking up 42mm and 37mm respectively. The highest official total was at Paynedale, which recorded 65mm, also the town's heaviest fall in six years. Rainfall totals rapidly declined further north, with Perth only seeing 11mm. East of Perth in the hills falls were a bit heavier, with Bickley seeing 26mm, its heaviest May rain in two years. Rain will push east today as the trough crosses the state, with places near the coast in the South Eastern coastal likely to pick up a further 5-10mm. However, in the wake of the system showers will persist near the coast, with places like Perth and Bunbury possibly picking up a further 10mm. From Friday a high pressure system will push into the region, with only a couple of light showers lingering about the coasts. By the weekend it will be mostly dry, although cloud is likely to increase on Sunday ahead of a low pressure trough.