The system is forecast to cross the Gascoyne coast on Saturday night bringing heavy rain and wind between Carnarvon and Exmouth in the state's Gascoyne coast.
The Bureau of Meteorology has downgraded Lincoln to a tropical low and it is forecast to remain at that intensity as it crosses the coast again.
"It's actually running out of time to become a tropical cyclone so it's looking more and more likely like it's going to stay in the tropical low for for its entire lifespan really," meteorologist Angus Hynes said.
It was previously predicted to intensify to a category 1 or 2.
Ex-Tropical Cyclone Lincoln is less likely to redevelop into a tropical cyclone but may cause strong winds, high tides and heavy rain around the Exmouth-Ningaloo, Gascoyne and Coral Bay areas on Saturday. For the latest track maps and updates: — Bureau of Meteorology, Australia (@BOM_au) https://t.co/VRWX6YDrNx pic.twitter.com/p339zUIdGJFebruary 23, 2024
Despite the intensity being downgraded, the weather system is still forecast to bring wind gusts of up to 90km/h and rainfall over the next 24 hours.
Rainfall totals between 40 and 80mm are forecast with isolated downpours of above 160mm anticipated on Saturday.
Flood watches are in place for the Pilbara and Gascoyne Coast Rivers on Saturday.
"If we start to see those river levels rising that's when we'll start to put those warnings out to people downstream a bit of a heads up that those floodwaters can be on the rise," Mr Hynes said.
The weather system is expected to move south in WA over the coming days bringing rainfall and wind to interior parts of the state.
My Hynes said the tropical low will likely avoid populated areas like Perth but may impact small communities in the southwest.
By Monday the tropical low should have all but dissipated, Mr Hynes added.
A cyclone yellow alert remains in place for people in or near coastal communities and offshore islands between North West Cape and Cape Cuvier including Exmouth. Coral Bay and Giralia.
Evacuation centres have been opened in Carnarvon and Exmouth and the North West Coastal Highway and six other key roads in the area have been closed.
Urban search and rescue specialists are among the dozens of emergency service personnel deployed to communities likely to be affected.
Lincoln crossed the Northern Territory coast from the Gulf of Carpentaria late last week as a category 1 cyclone before moving inland across the Top End and into WA as a storm.
It dumped heavy rain across a wide area triggering flood watches and warnings in northwest Queensland, the NT and northern WA before moving offshore again on Wednesday.