Tropical Cyclone Sean weakened over the South Indian Ocean west of Australia on Tuesday. At 10:00 a.m. EST on Tuesday the center of Tropical Cyclone Sean was located at latitude 26.7°S and longitude 107.3°E which put the center about 380 miles (610 km) west of Carnarvon, Australia. Sean was moving toward the south-southwest at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 977 mb.
Tropical Cyclone Sean weakened on Tuesday as it moved over cooler water in the South Indian Ocean west of Australia. An eye was no longer visible in the center of Sean’s circulation. Thunderstorms were still occurring in bands in the southern and eastern parts of Tropical Cyclone Sean. Bands in the northern and western parts of Sean’s circulation consisted primarily of showers and lower clouds. Storms near the center of Sean still produced some upper level divergence that pumped mass away to the southeast of the tropical cyclone. The removal of mass in the upper levels of the atmosphere was less than the inflow of mass in the lower levels, which caused the surface pressure to increase.
The size of the circulation around Tropical Cyclone Sean increased even though Sean was weakening. Winds to hurricane/typhoon force extended out 30 miles (50 km) from the center of Sean’s circulation. Winds to tropical storm force extended out 175 miles (280 km) from the center of Tropical Cyclone Sean.
Tropical Cyclone Sean will move through an environment that will be unfavorable for intensification during the next 24 hours. Sean will move over water where where the Sea Surface Temperatures are near 24°C. It will move under the eastern part of an upper level trough over the South Indian Ocean. The upper level trough will produce northwesterly winds are that will blow toward the top of Sean’s circulation. Those winds will cause moderate vertical wind shear. The combination of cooler water and moderate vertical wind shear will cause Tropical Cyclone Sean to continue to weaken during the next 24 hours.
Tropical Cyclone Sean will move around the western part of a high pressure system over Australia. The high pressure system will steer Sean toward the south during the next 24 hours. On its anticipated track, Tropical Cyclone Sean will move parallel to the coast of Western Australia.