Tropical Cyclone Seth formed east of Australia over the Coral Sea on Thursday night. At 10:00 p.m. EST on Thursday the center of Tropical Cyclone Seth was located at latitude 19.7°S and longitude 153.7°E which put it about 305 miles (495 km) east-northeast of Mackay, Australia. Seth was moving toward the southeast at 17 m.p.h. (27 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 992 mb.
Tropical Cyclone Seth formed from a tropical low that initially developed northwest of Darwin, Australia almost a week ago. The tropical low made landfall southwest of Darwin and then moved east across northern Australia. The tropical low weakened as it passed over land, but then it regained some organization when it passed over the southern Gulf of Carpentaria. The circulation around the tropical low began to strengthen after it moved over the Coral Sea east of Cairns. The inner end of a rainband wrapped around the southern side of center of circulation on Thursday night and the Australian Bureau of Meteorology designated the system as Tropical Cyclone Seth.
The strongest thunderstorms were occurring in the southern and eastern parts of Tropical Cyclone Seth. Bands in the northern and western parts of Seth’s circulation consisted primarily of showers and lower clouds. Storms near the center of Seth generated upper level divergence that pumped mass away to the southeast of the tropical cyclone. Winds to tropical storm force extended out 160 miles (260 km) to the southeast of the center of Tropical Cyclone Seth.
Tropical Cyclone Seth will move through an environment that is somewhat favorable for intensification during the next 36 hours. Seth will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the southwestern part of an upper level ridge centered northeast of Australia. The ridge will produce southwesterly winds that will blow toward the top of Tropical Cyclone Seth’s circulation. Those winds will cause moderate vertical wind shear. The wind shear will inhibit intensification, but it may not be strong enough to keep Seth from getting stronger. Tropical Cyclone Seth could intensify during the next 36 hours.
Tropical Cyclone Seth will move around the southwestern part of a high pressure system over the Coral Sea. The high pressure system will steer Seth toward the southeast during the next 36 hours. On its anticipated track Tropical Cyclone Seth will move over the Coral Sea parallel to the east coast of Australia. Seth could be located northeast of Brisbane in 36 hours. The steering currents could weaken during the weekend and Tropical Cyclone Seth could stall.