Heavy rain will target northeast New South Wales this weekend, causing flooding. Many areas north of Forster have already seen 100-200mm of rain this week, with some locations exceeding 300mm in 48 hours. As a result, catchments are saturated. The week's second bout of heavy rain will spread along the Hunter and Mid North Coast from tonight and further north, south and west this weekend. Widespread falls of 20-50mm are likely for the northern half of the coast and ranges, including Sydney, with isolated areas possibly picking up more than 200mm by the end of the weekend. The deluge is being triggered by a trough and low pressure system near the coast, which are drawing in moisture air from the Tasman Sea. Showers will start to ease from Sunday as the low moves over land, although heavy falls and storms remain a threat. Showers will continue over eastern New South Wales at the start of next week as onshore winds feed an inland trough. A Flood Watch is in place for most river valleys north of Sydney.