Tropical Cyclone Seth was spinning northeast of Brisbane, Australia on Friday night. At 10:00 p.m. EST on Friday the center of Tropical Cyclone Seth was located at latitude 22.6°S and longitude 157.7°E which put it about 465 miles (745 km) northeast of Brisbane, Australia. Seth was moving toward the southeast at 13 m.p.h. (20 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 strengthened on Friday morning, but then it weakened later in the day. An upper level ridge centered northeast of Australia and an upper level trough over eastern Australia were interacting to produce strong northwesterly winds over the Coral Sea on Friday night. Those winds were blowing toward the top of Seth’s circulation and they were causing moderate vertical wind shear. The wind shear was causing an asymmetric distribution of thunderstorms around Tropical Cyclone Seth. The strongest thunderstorms were occurring in bands southeast of the center of Seth. Bands in the northwestern half of the tropical cyclone consisted primarily of showers and lower clouds. Winds to tropical storm force extended out 155 miles (250 km) in the southern half of Tropical Cyclone Seth. Winds to tropical storm force extended out 100 miles (160 km) in the northern half of the circulation.
Tropical Cyclone Seth will move through an environment unfavorable for intensification during the next 24 hours. Seth will move over water where the Sea Surface Temperatures are near 28˚C. However, the upper level trough over eastern Australia and the upper level ridge over the Coral Sea will continue to produce strong northwesterly winds. Those winds will continue to cause strong vertical wind shear. The wind shear is likely to prevent Tropical Cyclone Seth from intensifying during the next 24 hours. There is a chance that the upper level winds could weaken in 24 hours, which might allow Seth to strengthen at that time.
The upper level trough and ridge will steer Tropical Cyclone Seth toward the south-southeast during the next 24 hours. The upper level trough could evolve into a cutoff low, which could pull Seth back toward the west during the second half of the weekend. On its anticipated track Tropical Cyclone Seth could be east of Brisbane in 36 hours.