Strengthening Tropical Cyclone Damien Nears Western Australia

Strengthening Tropical Cyclone Damien neared the coast of Western Australia on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Damien was located at latitude 19.4°S and longitude 116.6°E which put it about 100 miles (160 km) north-northwest of Karratha, Australia.  Damien was moving toward the south-southwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 963 mb.

A Warning was in effect for the portion of the coast of Western Australia from De Grey to Onslow including Dampier, Karratha and Port Hedland.  Initial Flood Warnings were in effect for the Coastal Pilbara Rivers.  A Flood Watch was in effect for the Pilbara and Gascoyne District.

Tropical Cyclone Damien continued to strengthen quickly on Friday.  A circular eye developed at the center of Damien.  A narrow ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Damien.  Storms near the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

The circulation around Tropical Cyclone Damien was relatively small.  Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Damien was 16.5.  The Hurricane Size Index (HSI) was 9.9 and the Hurricane Wind Intensity Size Index (HWISI) was 26.4.  Damien was capable of causing localized serious damage.

Tropical Cyclone Damien will move through an environment favorable for intensification during the next 12 hours.  Damien will move over water where the Sea Surface Temperature is near 30°C.  It will move under the western end of an upper level ridge over Australia.  The ridge will produce northerly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent Tropical Cyclone Damien from strengthening.  Damien could intensify into the equivalent of a major hurricane before it reaches the coast of Western Australia.

Tropical Cyclone Damien will move around the western end of a high pressure system over Australia.  The high will steer Damien toward the south during the next several days.  On its anticipated track the center of Tropical Cyclone Damien could make landfall on the coast of Western Australia near Dampier and Karratha in about 12 hours.  Damien will be capable of causing serious wind damage.  It will also produce a storm surge of up to 10 feet (3 meters) between Port Hedland and Dampier where the wind blows the water toward the coast.  The highest storm surge will occur near where the center makes landfall.  Tropical Cyclone Damien will also drop locally heavy rain and flash floods could occur in parts of Western Australia.