A low pressure system making its way across across southeastern Australia has been bringing rain and storms with it, and some of the best rain in over a year over the interior. The system initially made landfall over Western Australia on Sunday bringing some of the best September rain in years, and has been gradually moving east across the country this week. Central and northern parts of South Australia initially felt the impact on Tuesday morning where a band of thunderstorms fired up around the low which has not let up since, making its way into northwestern New South Wales this morning. Across the interior, the thunderstorms have brought some of the best rain in many months. For Arkaroola, the rain was the best the town has seen in September since 1981, recording 28mm in the 24 hours to 9am today. Tibooburra Airport had its heaviest rain since March 2012 and biggest September fall since 1998, recording 27mm. The storms had some bite as they moved through, dropping 5mm in just 10 minutes and wind gusts of 70km/h just before 7:30am. An associated trough with the low has also been spreading patchy rain areas and the odd thunderstorm over southern parts of SA, Victoria, Tasmania and NSW. However, totals have generally been less than 5mm. As the system continues on its eastern trajectory more healthy rainfall totals are expected, particularly over eastern Victoria and central and eastern NSW where further widespread falls of 15-30mm are expected with isolated totals up to 50mm possible under thunderstorms. Thunderstorms over western NSW today and over northern NSW and southeast Queensland tomorrow do have the potential to be severe with heavy rainfall, damaging wind gusts and large hail all a risk. The system will clear the nation on Friday, taking the rain and thunderstorms with it. By then, many places would have seen their best rain in several months. Cold upper level air in the wake of the system will cause a few showers and thunderstorms to linger over the nation's east coast on Friday and Saturday, although falls will be generally much lighter.