Punters cover up at Randwick Racecourse on Saturday. The State Emergency Service is urging people to tie down loose items in their backyard and to park cars under cover as heavy rain and strong winds are expected along the state's east coast on Saturday night. SES spokeswoman Becky Gollings said emergency service volunteers are preparing to help people affected by the rough weather, which is forecast to hit a large area from the mid north coast to the south coast, including Newcastle, Sydney and Wollongong. "We haven't had any calls yet but tomorrow and Monday we're really expecting the rain to start affecting the coastal areas of the state," Ms Gollings said. We are asking people to prepare now by clearing the gutter, tying lose items down and parking their cars under cover. People should also avoid rivers, creeks and storms as heavy rains could see flash flooding. Bureau of Meteorology New South Wales regional director Barry Hanstrum said that widespread rainfall of 100 to 150 millimetres could be expected from Saturday through to Tuesday, with localised heavy falls exceeding 200 millimetres. "The east coast low is forecast to deepen late on Saturday, affecting a large area of the New South Wales coast on Sunday and Monday, with persistent rainfall and the potential for flooding," said Mr Hanstrum. Strong to gale-force winds and heavy surf conditions may also be possible on Monday as the centre of the low moves closer to shore. Snow falls are also likely on the northern Tablelands down to 1200 metres on Monday. The Bureau issued a flood watch on Saturday morning that said there was more than 70 per cent chance that the heavy coastal rain would cause the Nepean, Georges, Wyong and Paterson Williams Valleys to flood. King tides, combined with the rain, are also predicted to cause flooding in the tidal zones of the Cooks and Woronora rivers.