The Bureau of Meteorology (BoM) is warning WA residents of an extremely strong cold front and deep low-pressure system that are set to impact southern parts of the state this weekend.
The "once in five-year" storm is set to bring destructive winds of 125km/h, rainfall totals of about 50mm, up to 8-metre swells and even a chance of tornadoes.
The BoM has issued a severe weather warning stretching from Kalbarri down to Esperance, saying it's likely to be the "strongest winter system we see this year".
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The storm is set to lash Perth with areas of heavy rain arriving on Saturday, which could cause flash flooding.
Senior Meteorologist Sarah Scully says gusty thunderstorms could bring damaging to locally destructive winds of more than 125km/h, coastal hazards and even a risk of tornadoes.
"This risk is expected to continue through until Sunday morning, and any tornadoes that do form will be very short-lived and very difficult to track," Scully said.
The impacted area may expand over the weekend as it's an "evolving weather situation", the bureau says.
"The strongest winds are expected with [a] low-pressure system that will push up into the south-west during Sunday evening," Scully said.
"Widespread destructive winds are expected to extend about the west coast and pushing into the south-west, where they will continue through until the early hours of Monday morning before that low-pressure system tracks into the bight, with the winds easing across the south-west and instead concentrating through the south coast."
Residents are being advised by authorities to ensure loose objects are either moved inside or locked down to prevent them becoming airborne.
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Western Power have cancelled all of their planned outages over the weekend and put crews on standby for potential weather-related outages from downed power lines.
Hillarys Yacht Club has cancelled its junior sailing event as a precaution.
"Our boatswains have their skipper's ticket, and they'll be patrolling the marina and the surrounding clubhouse, just to make sure that everything's secure and there's no damage," Rick Coate from Hillarys Yacht Club told 9News.
But one thing that may not be cancelled despite the wild weather is Sunday's clash between West Coast and Essendon at Optus Stadium.
"Sometimes people can overplay the bits of rain, these guys are so skilled and talented, its only really heavy torrential rain where strategy changes," Eagles coach Andrew McQualter said.
The warning for the west coast of Australia comes after the cancellation of a severe storm warning over on the east coast, where heavy rain and storms hammered parts of the country.
The Queensland and NSW coasts, as well as regions further inland, copped a soaking this week, driven by a low-pressure system off the coast.
Falls of up to 80mm were recorded in south-eastern Queensland, and up to 70mm in NSW down to the Central Coast, with the storm warning covering the Mid North Coast, Hunter, North West Slopes and Plains, and Northern Tablelands districts.
Weatherzone's lightning detector showed 460,000 strikes within 800km of Dalby in southern Queensland in the 24 hours to 9am yesterday.
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By the weekend, the forecasts for both Brisbane and Sydney show sunshine ahead, with temperatures peaking in the low 20s.
But on Saturday, another cold front will approach the south-east of the country.
As a result, showers will increase for South Australia, Victoria, Tasmania and inland parts of New South Wales, with colder southerly winds coming up behind that system.
