Rural Fire Service commissioner Shane Fitzsimmons said weather conditions would be worse than had previously predicted in his update this afternoon.
Warm, dry weather and strong winds are forecast — similar conditions to those experienced last Thursday when the blazes started.
“The conditions are forecast to be worse tomorrow than what we have been talking about for the last few days,” he said.
“We need to be really clear here, we cannot afford for complacency .. this cool change which has moved in is not what we need to be concerned about.
“We need to be focused on what is expected to come tomorrow […] It’s going to be a difficult and challenging day.”
All schools in the Blue Mountains, according to authorities, will be closed tomorrow along with some in the Hawkesbury and Southern Highlands.
Firefighters earlier used back-burning to join two fires burning in the Southern Highlands ahead of the worsening weather conditions.
“We only need an ember, part of a spotover…to break off and take hold under the conditions that we’re expecting tomorrow, for it to take off again,” he said.
There are fears all of the blazes burning in the mountains could join into one huge inferno which would be near-impossible to control.
There are still around 1600 kilometres of fire front in New South Wales, with more than 200 homes and one life lost since the crisis began.
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