Rain is set to finally ease but Sydney homes still threatened as dam tipped to overflow for second time in three months

Warmer weather is on the horizon in Sydney as the onslaught of one of the wettest Augusts on record looks to be coming to a close. Despite up to 8mm of rainfall expected by the end of the day, Sydney is expected to only receive 0-2mm across the weekend before gloomy skies are set to disappear by the turn of the week. Similar conditions are expected in most major cities across the nation. The arrival of a westerly airstream will increase temperatures in Sydney to 20C and 22C on Monday and Tuesday respectively before a top of 23C come Wednesday, the warmest weather in the city for months. In more encouraging news, the rain looks to move away entirely from northeast coast by Tuesday. Despite this, Sydney’s most critical dam will likely overflow on Friday after days of relentless rain, tipped to spill around 15 billion litres of water. Western Sydney residents downstream of Warragamba Dam are being warned to monitor river rises and flood warnings as the excess water gushes into Sydney. The dam was at 98 per cent of its more than 2000 gigalitre capacity at 9.30am on Friday, with more rainfall on the way. “Rainfall of 90mm has been received over the past few days in the Warragamba Dam catchment,” a WaterNSW spokesperson said. “Smaller dams including Woronora, Cataract, Cordeaux, Nepean, Avon, Wingecaribee and Tallowa in Greater Sydney continue to spill.” This will be the second time in three months that the dam - which provides 80 per cent of Sydney’s drinking water - has overflown, spilling 20 gigalitres on May 25. Dozens of flood alerts The NSW State Emergency Service (SES) has issued 42 flood alerts as of 7am on Friday, with warnings stretching from Wollongong on the south coast to Goondiwindi at the Queensland-NSW border. Alerts have been issued for residents at Gunnedah, in the NSW northwest, with those near Talibah Flats and Old Blue Vale Rd and Kelvin Rd told to “prepare to isolate”. The warnings say there is a risk of major flooding by Friday evening. “You should monitor the situation and prepare to be isolated by floodwater,” the SES warnings read. “Consider the effects isolation will have on family, work, and educational commitments. “You may be trapped without power, water, and other essential services and it may be too dangerous for NSW SES to rescue you.” NSW SES has responded to more than 600 incidents and at least 10 flood rescues since the weather event began, all 10 rescues involving people driving onto flooded roads. “We’re dealing with two different weather systems here, the first one, which occurred earlier this month, is still impacting areas along the Namoi and Barwon River, so those communities are experiencing flooding from previous events,” NSW SES Deputy Commissioner Debbie Platz told ABC News. “Then the events of the last 48 hours, which is topping up all our river systems that are on the coastal catchments and in the north west plains areas. “We had a number of houses in Sydney yesterday, about 60 in the Kurnell area, that had floodwaters into their properties that we were assisting with. “Our other biggest area for incidents has been around the Port Macquarie area.” Residents have been warned that their houses could still become inundated, even after the rain subsides. “Some communities, particularly in low-lying areas around Gunnedah, have to prepare to isolate because the floodwaters are rising,” Ms Platz said. “We could see inundation in the low areas, the catchments are really primed, and they’re rising quickly.” Dangerous river rises Isolated falls across the state have totalled more than 200mm in 48 hours, with areas of the Central Coast, North West Slopes, and the Hunter and Illawarra regions among the hardest hit. The Namoi River at Gunnedah and Peel River at Tamworth are both tipped to flood, with the Namoi likely to exceed major flood levels of 7.9m. Rivers around Sydney, including the Hawkesbury and Nepean, have already reached minor flood levels, with water inundating the Menangle Bridge southwest of Sydney. Sydney has recorded its wettest August in 27 years, receiving more than 350mm of rain already this month. The total is about four times the average monthly rainfall for the city. In the 24 hours to 9am on Friday, the highest falls included 165mm at Tallebudgera Creek on the Queensland/NSW border, 135mm at Kingscliff in the Northern Rivers and 80mm at Port Macquarie on the Central Coast. Floodwaters have cut off roads in parts of NSW, including the Princes Highway near Dunmore on the South Coast and Menangle Rd in Sydney. End in sight for east coast The relentless rain is predicted to finally ease from Friday afternoon, with just a few light showers around Sydney and Newcastle forecast for the rest of Friday. “We’re seeing this prolonged rainband finally shifting off the east coast and moving towards the ocean, drawing moisture out over the Tasman sea,” Bureau of Meteorology senior meteorologist Angus Hines said. “For those more populated areas of Sydney and the Illawarra, rainfall totals shouldn’t get above 10mm on Friday.”