A tropical cyclone named Mitchell is off the coast of northern Western Australia and is expected to grow stronger. It was near Port Hedland and moving southwest toward Karratha on Saturday morning. Authorities say it will hit the western Pilbara coast late Sunday afternoon. Meteorologists predict Mitchell will become a severe category three cyclone as it passes just north of Karratha Saturday night and then stays close to the Pilbara coast Sunday. Dangerous wind gusts of up to 170 km/h could strike Karratha, Dampier, Wickham on Saturday night, and Onslow on Sunday. A watch and act warning covers Whim Creek to Mardie, including Barrow Island and Montebello Islands. Residents there must prepare for shelter to protect lives and homes. People from Pardoo Roadhouse east of Whim Creek, south of Mardie to Carnarvon, and Pannawonica should watch weather updates and get ready for severe conditions. An evacuation center opened at Karratha Leisureplex Saturday midday. Those evacuating should bring medicines and ID but leave pets behind. Several ports including Ashburton, Cape Preston West, Dampier, Port Hedland, and Varanus Island have shut due to the storm. Port Hedland may see up to 130mm of rain Saturday, raising flood risks. Authorities warn flash floods could affect central and west Pilbara and west Gascoyne through Monday. High tides add to the flood danger around Karratha early Sunday and Onslow Sunday afternoon. Meanwhile, flooding continues in Northern Territory. Over 400 people evacuated by bus from Daly River to Darwin on Wednesday face a wait to return as river floods peak next week. Incident controller Supt David Moore said 298 evacuees, including 110 children, stay at the Foskey Pavilion in Darwin Showgrounds.