As the city bakes in 40C conditions and fire fighters battle multiple blazes, authorities are now bracing for another weather event predicted to strike overnight.

A severe weather warning has been issued, urging people in Perth and the State’s Lower and South West to prepare for “unusually strong” wind gusts that could top 90km/h.

“Easterly winds of this strength generally occur on average once every two to three years” the Bureau of Meteorology said.

A strong ridge of high pressure will develop south of WA, generating the damaging winds from late Monday evening through to Tuesday morning, according to BoM.

Camera Icon A strip of WA is expected to be peppered by strong winds overnight. Credit: Bureau of Meteorology

The Department of Fire and Emergency Services said properties in Dwellingup, Ellenbrook, Gingin, Kalamunda, Midland and Mundaring were most likely to face the barrage.

It advised people lock down loose items, ensure they have an emergency kit, keep pets in a safe area, move vehicles undercover and secure boats.

It said electrical appliances should be unplugged and people should avoid using landline telephones if there is lightning.