Category three tropical cyclone bringing severe weather to Port Hedland, Broome, Dampier Peninsula, De Grey, Cape Leveque

The system is currently estimated to be about 600km to the northeast of Broome, and continues to intensify.

A tropical cyclone watch is currently in place between Cape Leveque and Broome, however not including Broome itself.

Exposed coastal areas on the Dampier Peninsula are expected to see the first of the damaging winds and heavy rainfall as the system moves through on Wednesday April 12.

BOM's Western Australia and Northern Territory manager Todd Smith said the system is expected to continue to track west on Wednesday, and then head south, before curving back inland to the southeast.

"We're really urging residents in the West Kimberley and East Pilbara to pay attention to the warnings from the Bureau and DFES as this system develops," Mr Smith said.

Cyclone Ilsa is expected to hit the coast between Broome and Port Hedland between late Thursday and early Friday, bringing damaging winds and heavy rainfall, which could result in localised flash flooding.

"We may see conditions start to deteriorate on Thursday as the system approaches the coast," Mr Smith said.

"Be in a safe place before the system reaches the coast."

Once the system crosses the coast the regions can expect to see destructive wind gusts near the centre of the system, abnormally high tides and large waves - particularly to the east of where the system crosses - and localised flash flooding.

Over the weekend the cyclone will travel inland, where the heavy rainfall is expected to continue, affecting the De Grey river catchment.

"We might see upwards of 200mm per day, we would expect to see some strong river rises within the De Grey river as a consequence of that," Mr Smith said.

Once the system has moved inland it is expected to weaken slowly, however areas will still be affected by flooding.

"Significant rainfall totals can still be expected even inland.

"There will be lingering flood waters, the rain that it dumps in the De Grey will make it's way down stream.

"So we could see some impacts on the Great Northern Highway because that water does need to flow down stream."

DFES Commissioner Darren Klemm said the cyclone is expected to be a category three or higher.

A system of this kind can bring destructive winds in excess of 200km/h not just near the centre of the system but even up to 50-100km away from the centre, depending on the size of the system.

"Make sure that you're prepared, there's no excuse for not being prepared," Mr Klemm said.

"Everyone from Broome to Port Hedland need to make sure they're enacting their plan, now is the time to be cleaning up around your home, make sure you've got an emergency kit, and make sure you're keeping up to date with the DFES warnings that come out into the days ahead.

"It's been some 10 years since there's been a cyclone greater than category three through that area," he said.

Mr Klemm said people need to be aware of not just the cyclone path but the surrounding areas.

"A lot of people focus on the black line in the middle of the track map, but that area in the grey is where the cyclone has the potential to go," he said.

"It doesn't take much for the track of a cyclone to change.

"You've got time now in the next two or three days to make sure that you and your family are well prepared."

DFES has deployed 26 personnel to Broome and Bidyadanga as well as crews and two helicopters heading for Karratha in preparation for rescues.

The advice for those on holidays in the area is to rethink your travel plans and begin to move south.

"If you're on Eighty Mile Beach, now is the time to be packing up and heading to the south is the best way to be out of there," Mr Klemm said.

From Thursday onwards, Mr Klemm said it would be very likely major highways in the area would be closed.

Mr Klemm said flight cancellations are up to the airports' discretion, but are likely to occur from Thursday onwards.

By early next week it is expected the system will be out of Western Australia.