Stormy weather is set to batter southwestern parts of Western Australia from later today and into Monday as a slow-moving low pressure system crosses the region. There is already an impressive line of thunderstorms offshore this morning, which is likely to sweep across the coast from late this afternoon or evening. The band will bring a burst of heavy rain and wind, with places as far north as Denham likely to be affected, although locations from Geraldton and south will be hardest hit. After some easing for much of Monday morning, another burst of showers and thunderstorms will move through from late in the morning, mainly south of Jurien Bay. Further heavy falls are likely, with even the risk of small hail as a pool of cold upper level air moves overhead. By the time the two bands have passed, many parts of the South West Land Division will see widespread falls of 20-50mm, including Perth. The rain is good news for the region, which is currently seeing a warm and dry August. Perth has only recorded 5mm for the month so far, and Bunbury 11mm, with daytime temperatures averaging more than two degrees above the long-term mean. Looking further ahead, a series of cold fronts will bring showers on most days for the remainder of the week, with most of the region likely to pick up a further 10-20mm by the start of next weekend.