Firefighters are battling a blaze at a Newcastle home that may have been sparked by a lightning strike as thunderstorms and heavy rain swept over the area on Friday morning.
The Bureau of Meteorology has issued a severe thunderstorm warning for parts of the mid north coast and Hunter forecast districts, where residents have been told to expect large hailstones, heavy rain and damaging wind early on Friday.
A Fire and Rescue NSW spokesman said firefighters were called to a blaze at a home in Seaham Street in Holmesville, a suburb of Newcastle, about 7.30am on Friday.
Initial investigations suggested the fire may have been started by a lightning strike, however that cause had not been confirmed, the spokesman said.
"It is an electrical fire, but we are just trying to extent of damage. It hasn't been confirmed whether it was a lightning strike," he said.
There were no initial reports of injuries.
Weatherzone meteorologist Max Gonzalez said the storms began in the Newcastle area about 5am on Friday, and had been moving slowly towards the coast.
"They're very slow moving, taking about half an hour or so to move on," he said.
Locations expected be worst affected include Newcastle, Cessnock, Maitland, Port Macquarie and Taree.
In the hour to 7.45am on Friday, 76 millimetres of rain was recorded at the small town of Nabiac, on the mid north coast, according to the Bureau of Meteorology.
At 7.55 am, severe thunderstorms were detected on weather radars near Dora Creek and Lake Macquarie.
They were forecast to hit Dooralong, Boolaroo and Warners Bay by 8.25 am and Belmont, Charlestown and Swansea by 8.55 am.
The State Emergency Service advised people to keep clear of creeks and storm drains, and to avoid walking, riding or driving through flood water.
Showers also drenched a large part of Sydney on Friday morning, but they largely fell after Anzac Day dawn services around the city.
Showers in Sydney are expected throughout the day, easing in the afternoon before clearing during the evening.
A top of 22 degrees is forecast in the city and 21 degrees in the west.
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