Thunderstorms along Australia's eastern seabord on Saturday died overnight but are developing again in the heat of Sunday afternoon with potential for severity. The storms are popping up on the ranges and their slow movement gives them a good chance of producing flash flooding, similar to Saturday's storms. Canberra, Sydney and Brisbane are all a good chance of getting a thunderstorm on Sunday afternoon and evening. On Saturday, the storms dumped brief heavy rain, mostly just inland of the coast. Rain rates in excess of 10mm in 10 minutes affected western Sydney, Gosford, Taree, Coffs Harbour, Toowoomba and Brisbane, enough to lead to brief flash flooding. Most of these centres ended up with 20-to-30mm in under an hour. On Monday and Tuesday, the trough causing these storms will still be in the area, giving Canberra, Sydney, Brisbane and most places in between a chance for more thundery downpours and flash flooding. With more wet days than dry ones, much of region from eastern Victoria along the NSW coast and ranges to southeast Queensland is having a wetter-than-average summer. Keep up-to-date with warnings and storm forecasts at weatherzone.com.au.