Parts of New South Wales are on flood watch as a week of severe weather continues over eastern Australia. The week started with an intense thunderstorm outbreak when an upper-level low pressure system interacted with warm and moisture-laden air flowing in from the Tasman Sea. Severe storms produced damaging winds, flooding rain and large hail in parts of Queensland and New South Wales. While storms are still active in some areas west of the ranges today, the focus of severe weather has shifted to a low pressure trough deepening near the coast. More than 100mm of rain fell during the 24 hours to 9am today in coastal and adjacent inland areas between about Gladstone and Lismore. Tewantin recorded 189mm, which is their heaviest March rain in 62 years. Noosaville registered the biggest fall in the region with 268mm. South of the border, Mullumbimby had 129mm up to 9am, the town's heaviest fall since last June and about half a month's worth of rain for this time of year. Unsurprisingly, this deluge triggered flash flooding in both states this morning. Since 9am today, the heaviest rain has fallen around Coffs Harbour near the deepening trough. Close to 150mm was recorded in in just three hours at Sawtell. Heavy falls will continue tonight and on Thursday in northeast New South Wales as the deepening trough develops into a low pressure system. A severe weather warning has been issued for flash flooding in parts of the Northern Rivers, Mid North Coast and Northern Tablelands. There is also a risk of minor to moderate river flooding in the Richmond-Wilsons, Orara, Coffs Coast, Bellinger, Nambucca, Macleay and Hastings river valleys during the second half of this week, prompting a flood watch. Looking further ahead, there is some uncertainty regarding the position of one or two low pressure systems near the east coast at the end of the week. There is potential for further heavy rain and flooding along the north coast of New South Wales from Friday and in southeast Queensland again from the weekend.