Western Sydney residents are being warned to prepare for bushfires with record heat and strong winds to hit Sydney today.
The Bureau of Meteorology has predicted temperatures to soar to 39 degrees on Wednesday, an October record.
A cool relief, with winds up to 80kmh, is expected to come through during the afternoon and persist late into the evening.
A total fire ban has been declared for 15 of the state’s 21 regions, with extreme fire danger warnings issued for greater Sydney, greater Hunter and Illawarra/Shoalhaven regions.
The fire risk areas include Doonside, Marsden Park, Riverstone, the Hills district, Hawkesbury, Windsor and the Blue Mountains.
Fire service Commissioner Shane Fitzsimmons said there is the potential for some locations to reach a "catastrophic" fire threat if the weather deteriorates beyond what is forecast.
“These are dangerous conditions, and it’s critical that you understand the risk and make your final preparations now – do not leave it until the last minute,” Commissioner Fitzsimmons said.
“Under these conditions, any fire that starts and takes hold will spread quickly and may threaten homes and lives without warning."
Dozens of aircraft, hundreds of fire trucks and thousands of volunteer firefighters will standing by to tackle any emergencies.