Tropical Cyclone 03S Moving West of Australia

A tropical cyclone designated 03S moved farther west of Australia and weakened on Saturday.  Tropical Cyclone 03S moved across northern Australia as a low pressure system last week before move off the coast near Broome.  After the center of the low moved over the South Indian Ocean thunderstorms developed near the core of the system and the Australian Bureau of Meteorology classified it as a tropical low.  The tropical low strengthened into the equivalent of a tropical storm on Friday night, but the Australian Bureau of Meteorology did not give the system a name.

At 7:00 p.m. EST on Saturday the center of Tropical Cyclone 03S was located at latitude 19.5°S and longitude 109.8°E which put it about 335 miles (540 km) northwest of Learmonth, Australia.  Tropical Cyclone 03S was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 994 mb.

Tropical Cyclone 03S has a well defined low level circulation but the distribution of thunderstorms is asymmetrical.  Most of the stronger thunderstorms are forming in bands west of the center of circulation.  There are also bands in the eastern half of the circulation but they consist primarily of low clouds and rain showers.  Strong easterly winds in the upper levels are shearing the tops off of any thunderstorms that develop in the eastern part of the circulation.  The easterly winds are also inhibiting upper level divergence to the east of the center.

Tropical Cyclone 03S will move into an environment that will be unfavorable for intensification.  Tropical Cyclone 03S is moving over water where the Sea Surface Temperature is near 26°C, but it will move over cooler water during the next several days.  An upper level ridge centered over Australia is generating easterly winds which are blowing across the top of the tropical cyclone.  The easterly winds are causing moderate vertical wind shear and are responsible for the asymmetrical distribution of thunderstorms.  Tropical Cyclone 03S is likely to weaken slowly during the next several days.

A subtropical ridge will continue to steer Tropical Cyclone 03S to the west during the next few days.  On its anticipated track Tropical Cyclone 03S is expected to move farther away from Western Australia as it weakens.