The Weather Bureau has re-issued a severe weather warning for parts of the State including Perth, warning of damaging winds, hail and heavy rain.
The warning covers an area from Geraldton to Gascoyne Junction, Dalwallinu, Lake Grace, Mt Barker, Bridgetown and Perth.
It says there is a risk of severe thunderstorms this afternoon and evening.
Stifling humidity followed an electrical storm that hit the city overnight and this morning, blacking out traffic lights and thousands of homes and businesses and delaying flights at Perth Airport.
Several of Perth’s major beaches were closed because of lightning strikes, including Cottesloe, City Beach, Floreat, Hillarys and Sorrento but have been reopened.
Today’s forecast is for thunderstorms and a maximum of 35 degrees, with that maximum rising to 37 degrees tomorrow.
Fine weather is expected for Saturday, before possible storms and 36 degree maximums from Sunday to Wednesday.
Nearly 30,000 homes were without power earlier this morning. The Belmont Forum shopping centre was also closed due to the power outage.
As of 11am, there were still 13,000 homes in the dark.
Main Roads said lights were out in the Perth CBD, and northern and southern suburbss
The sign greeting Belmont Forum Shopping Centre customers this morning. Picture: Simon Hydzik/7 News
A lightning strike is believed to have sparked a fire which caused $100,000 damage to a house in Canning Vale.
Firefighters were called to a newly-finished one-storey home on Woodland Dale, near Fairfield Gardens, about 6.10am.
The fire had spread from a bedroom to a kitchen and was threatening to jump the fence into a neighbouring property.
It was extinguished about 40 minutes later.
Next door neighbour, Kylie, 32, said she was sure the fire was caused by lightning.
“You could hear the thunder overhead and I just heard this loud bang,” she said.
“It sounded like a clap of thunder right on top of us.
Firefighters at the scene of the fire. Picture: Simon Santi/The West Australian
“Then someone came knocking on the door saying the house next door was on fire.”
She said her neighbours had just finished building their house and were yet to move in.
Western Power crews are working to restore supplies to homes and businesses.
Western Power spokesman Simon Bailey said crews had been repairing faults and re-routing power across Perth.
The worst hit suburbs were Belmont and South Perth, with 3500 and 3000 outages respectively.
“We have 27,000 customers across the metro area affected by the lightning strikes,” he said.
“The lightning strikes are still happening.
Delays at Perth Airport. Picture: Simon Hydzik/7 News
“Our crews have been out there all hours of the morning and we’ll have more crews coming on this morning.”
Mr Bailey urged motorists to stay well away from fallen power lines and report them to Western Power on 13 13 51.
Domestic departures at Perth Airport were stopped until 6.30am as the storm hit, delaying dozens of flights.
The airport tarmac was placed off limits four times today due to lightning in the area.
Passengers were not allowed on or off aircraft while the ban was in place.
The first domestic departure of the day was scheduled for about 5am, but passengers did not start boarding until after 7am.
The delays are expected to cause flow-on effects throughout the day and passengers are urged to call their airlines for information.
The storm had less of an impact on international operations, delaying one Air Asia departure and forcing passengers on an Air Asia arrival from Kuala Lumpur to wait on the runway for 40 minutes.
A Perth Airport spokeswoman said each airline made its own decision about storms.
“When the storm is within five to seven nautical miles of the airport, the airlines make the decision to remove their ground staff or basically close the ramp,” she said.
“The weather cell was very, very slow moving.
“We didn’t have any departures until 6.30am and it will take a little while to clear that backlog.”
Drivers have been told to use caution.
The city’s longest dry spell in more than a decade - 61 days- ended with the storm dropping 18.6mm in the metropolitan gauge.
The lightning storm hit the southern suburbs and spread north.
It now appears to be moving south east.
The State Emergency Services has received several storm-related calls but no major damage has been reported.
State Emergency Service volunteers were called out to a property in Canning Vale which was taking in water through a damaged roof.
The Department and Fire and Emergency Services said lightning strikes caused more than 20 minor fires.
Crews at the Pinjar fire ground left the area as the storm passed through to avoid the lightning.
There was a steady stream of pole top fires, palm tree fires and grass fires throughout the night, particularly in the south-eastern suburbs.
Bureau of Meteorology Noel Puzey said it was not uncommon to see a lot of spot fires during the first storms of the summer.
“That’s always the risk with thunderstorms,” he said.
“There’s lots of different sorts of lightning and some of it hits the ground.
“When it’s dry in summer and you get these thunderstorms you’re possibly going to get the spot fires.”
Summer storm over Perth. First time photographing lightning while simultaneously being devoured by mozzies! pic.twitter.com/IV8ELmcq6l— Jarad Finneran (@JazPeterFinn) January 28, 2015
“Boyup Brook had about 25 spot fires going from one system yesterday but luckily there was enough rain around to put them out.”
Mr Puzey said the rain ended the equal 13th longest dry spell in Perth since records started in 1876.