Tropical Cyclone Ilsa intensified rapidly over the South Indian Ocean northwest of Australia on Tuesday morning. At 8:00 a.m. EDT on Tuesday the center of Tropical Cyclone Ilsa was located at latitude 15.2°S and longitude 120.5°E which put it about 225 miles (360 km) north-northwest of Broome, Australia. Ilsa was moving toward the southwest at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 984 mb.

A Tropical Cyclone Watch was in effect for the portion of the coast of Western Australia from Beagle Bay to Whim Creek. The Tropical Cyclone Watch included Broome and Port Hedland.

After moving southwest over the South Indian Ocean for three days without strengthening, a low pressure system previous designated as a tropical low intensified rapidly on Tuesday morning. The Australia Bureau of Meteorology designated the system as Tropical Cyclone Ilsa.

The circulation around Tropical Cyclone Isla was organizing quickly. The inner end of a rainband wrapped around the western side of the center of Ilsa’s circulation. Bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center generated more upper level divergence that pumped mass away from the tropical cyclone. Winds to tropical storm force extended out 100 miles (160 km) from the center of Tropical Cyclone Ilsa.

Tropical Cyclone Ilsa will move through an environment very favorable for intensification during the next 24 hours. Ilsa will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the axis of an upper level ridge that extends from northern Australia to the South Indian Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Cyclone Ilsa is likely to continue to intensify rapidly during the next 24 hours. It will strengthen to the equivalent of a hurricane/typhoon. Ilsa could intensify to the equivalent of a major hurricane within 48 hours.

Tropical Cyclone Ilsa will move around the northwest part of a high pressure system over western Australia. The high pressure system will steer Ilsa toward the southwest during the next 24 hours. Tropical Cyclone Ilsa will move toward the south when it reaches the western end of the ridge on Wednesday. On its anticipated track, Ilsa is likely to make landfall on the coast of Western Australia between Broome and Port Hedland within 60 hours. The center of Tropical Cyclone Isla could make landfall near Wallal Downs. Ilsa is likely to be the equivalent of a major hurricane when it makes landfall.