Tag Archives: Kunawarritji

Tropical Cyclone Ilsa Hits Western Australia

The center of Tropical Cyclone Ilsa hit the coast of Western Australia just to the east of Pardoo Roadhouse on Thursday. At 11:00 a.m. EDT on Thursday the center of Tropical Cyclone Ilsa was located at latitude 19.9°S and longitude 119.7°E which put it about 10 miles (15 km) northeast of Pardoo Roadhouse, Australia. Ilsa was moving toward the southeast at 15 m.p.h. (24 km/h). The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h). The minimum surface pressure was 926 mb.

A Tropical Cyclone Warning was in effect for the coast of Western Australia from Bidyadanga to Port Hedland. The Tropical Cyclone Warning extended inland to include De Grey, Marble Bar, Nullagine, Telfer, Parnngurr and Kunawarritji.

Tropical Cyclone Ilsa was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale at the time of landfall. A very small circular eye was present at the center of Ilsa’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Ilsa. Storms near the core generated strong upper level divergence that pumped large quantities of mass away from the tropical cyclone.

A weather station at Bedout Island measured a sustained wind speed of 135 m.p.h. (218 km/h) when the western side of the eyewall of Tropical Cyclone Ilsa passed over it. The weather station also measured a wind gust of 178 m.p.h. (288 km/h).

Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of Tropical Cyclone Ilsa at the time of landfall. Winds to tropical storm force extended out 140 miles (225 km) from the center. The Hurricane Intensity Index (HII) for Tropical Cyclone Ilsa was 31.6. The Hurricane Size Index (HSI) was 17.6 and the Hurricane Wind Intensity Size Index (HWISI) was 49.2. Tropical Cyclone Ilsa was similar in size and intensity to Hurricane Laura when Laura hit southwest Louisiana in 2020.

Tropical Cyclone Ilsa will move around the southern side of a high pressure system over northern Australia. The high pressure system will steer Ilsa toward the east-southeast during the next 24 hours. On its anticipated track, the center of Tropical Cyclone Ilsa will pass near Telfer and Kiwirrkurra.

Although Tropical Cyclone Ilsa will weaken as it moves farther inland over Western Australia, it will take a while to spin down. Ilsa will bring strong winds and locally heavy rain to Western Australia. The strong winds will be capable of causing regional severe damage. Ilsa could also produce strong winds in De Grey and Telfer when it moves inland. Heavy rain could cause flash floods in some locations. Flood Warnings are in effect for the De Grey River and the Sandy Desert. Flood Watches are in effect for the West Kimberley, Western Desert, Warburton and Salt Lake Districts. Tropical Cyclone Ilsa could bring gusty winds to Kiwirrkurra during Friday.