On Friday and Saturday thunderstorms are set to spark up across northern New South Wales and parts of southern Queensland as a low pressure trough deepens. Today, a weak trough is bringing patchy light rain across NSW, associated with a weakening low pressure system further south. Tomorrow, a spring-like set-up is likely to take hold of eastern Australia, producing thunderstorms. Cold air from the south is ready to clash with warm air from the north along the boundary of a trough in a way more typical of early spring than mid-winter. Storms are likely to be heaviest and most widespread over northern parts of the Central West Slopes and Plains, with surrounding regions also a fair chance to see storms. On Saturday the trough will move further northeast, bringing storms to northeastern NSW and southeastern QLD. Even Brisbane faces a risk of thunderstorms on this day, most likely in the evening as the trough moves over. Damaging wind gusts are a risk with these thunderstorms, particularly on Friday. Large hail of around 2-3cm cannot be ruled out either due to the powerful lifting component in the atmosphere. On Sunday a high pressure ridge will move in again, bringing back the dry and sunny winter weather.