Source: Bureau of Meteorology

Media: The Standard Emergency Warning Signal should NOT be used with this warning.

TOP PRIORITY FOR IMMEDIATE BROADCAST
TROPICAL CYCLONE ADVICE NUMBER 29
Issued at 8:50 am WST on Thursday 13 April 2023

Headline:
Severe Tropical Cyclone Ilsa, now category 4, is expected to cross the coast between Port Hedland and Bidyadanga Thursday night or Friday morning.

Areas Affected:
Warning Zone
Area south of Broome to Whim Creek, including Port Hedland and extending inland as far as Parnngurr, including Nullagine, Marble Bar and Telfer.

Watch Zone
Inland areas from Parnngurr to Kiwirrkurra, and southwest of Balgo.

Cancelled Zone
None.

Details of Severe Tropical Cyclone Ilsa at 8:00 am AWST:
Intensity: Category 4, sustained winds near the centre of 165 kilometres per hour with wind gusts to 230 kilometres per hour.

Location: within 20 kilometres of 17.7 degrees South 118.9 degrees East, estimated to be 290 kilometres north of Port Hedland and 295 kilometres northwest of Wallal Downs.

Movement: south southwest at 15 kilometres per hour.

Severe Tropical Cyclone Ilsa has intensified into a category 4 system, and is moving south. Ilsa is expected to turn to the southeast this afternoon and move towards the east Pilbara coast.

A severe impact will occur along the coast and adjacent inland parts to the east of Port Hedland and west of Bidyadanga, most likely between Pardoo Roadhouse and Wallal Downs, later tonight or early Friday morning. During Friday, Ilsa is forecast to maintain tropical cyclone intensity as it tracks past Telfer and further inland across the Northern Interior district. The system is expected to weaken below tropical cyclone strength overnight Friday as it moves east into southern parts of the Northern Territory.

Hazards:
The VERY DESTRUCTIVE CORE of Ilsa, with extreme gusts up to 275 km/hr is expected to impact the area between De Grey and west of Bidyadanga late Thursday night or early Friday morning, before tracking inland. Very destructive wind gusts up to 170 km/hr are possible at Telfer during Friday if the centre of Isla passes close by.

DESTRUCTIVE WINDS with gusts to 155 km/h may develop near the coast between Bidyadanga and Port Hedland during this afternoon or evening before extending inland as far as Marble Bar tonight and to Telfer during Friday.

DAMAGING WINDS with gusts to 90 km/h may develop between the area south of Broome to around Port Hedland from early this afternoon. DAMAGING winds may extend further west to Whim Creek later today if Ilsa moves further to the west. DAMAGING WINDS are expected to extend inland to Marble Bar during Thursday night, to Telfer early Friday, Parnngurr by Friday afternoon, and possibly to Kiwirrkurra by Friday evening.

HEAVY RAINFALL and squally thunderstorms are expected over the western Kimberley, and may extend to the eastern Pilbara during today and Northern Interior from Friday. 200 to 400 mm of rainfall is possible during today and Friday near where Ilsa crosses the coast.

ABNORMALLY HIGH TIDES are possible about the coast between Broome and Port Hedland today and as the system crosses the coast tonight or during early Friday morning. In some locations the tide may be close to or exceed the highest astronomical tide of the year.

Recommended Action:
DFES advises of the following community alerts (effective as of 8am 13/04/2023):

YELLOW ALERT: People between Bidyadanga and Whim Creek including Port Hedland extending inland to include Marble Bar, Nullagine and Telfer, people need to act and get ready to shelter from a cyclone.

BLUE ALERT: People south of Broome to Bidyadanga (not including Bidyadanga), inland areas to Parnngurr and Kiwirrkurra and from Roebourne to Whim Creek (not including Whim Creek), need to prepare for cyclonic weather and organise an emergency kit including first aid kit, torch, portable radio, spare batteries, food, and water.

ALL CLEAR: People in or near Beagle Bay to Broome (including Broome).

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