Tag Archives: Tropical Cyclone Seth

Tropical Cyclone Seth Speeds South

Tropical Cyclone Seth sped toward the south over the Coral Sea east of Australia on Saturday night. At 7:00 p.m. EST on Saturday the center of Tropical Cyclone Seth was located at latitude 25.8°S and longitude 159.0°E which put it about 385 miles (620 km) east-northeast of Brisbane, Australia. Seth was moving toward the south at 25 m.p.h. (41 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 987 mb.

An upper level trough over eastern Australia and an upper level ridge east of the Coral Sea were combining to steer Tropical Cyclone Seth quickly toward the south on Saturday night. The structure of Seth’s circulation was beginning to resemble a subtropical cyclone. The strongest thunderstorms were occurring in bands south of the center of circulation. Bands in the northern half of Tropical Cyclone Seth consisted primarily of showers and lower clouds. The upper level trough and upper level ridge were producing strong northerly winds that were blowing toward the top of Seth’s circulation. Those winds were causing strong vertical wind shear. Drier air was wrapping around the northern side of Tropical Cyclone Seth. The strong vertical wind shear and drier air were causing the asymmetrical distribution of thunderstorms. The distribution of winds around Seth was also asymmetrical. Winds to tropical storm force extended out 205 miles (335 km) in the southern half of Tropical Cyclone Seth. Winds to tropical storm force extended out 90 miles (150 km) in the northern half of Seth’s 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 26˚C. However, the upper level trough and upper level ridge will continue to cause strong vertical wind shear. Drier air in the northern half of Seth’s circulation will inhibit the formation of thunderstorms. Tropical Cyclone Seth could make a transition to a subtropical cyclone during the next 24 hours. Seth could maintain its intensity during the transition, but it is likely to weaken during the next few days.

The upper level trough will steer Tropical Cyclone Seth quickly toward the south during the next 12 hours. The upper trough could make a transition to a cutoff low during the next day or so. The center of Seth could move under the cutoff low, which would cause Seth to move more slowly. The cutoff low and Tropical Cyclone Seth could drift west toward Australia during the next several days. On its anticipated track Tropical Cyclone Seth could move slowly toward Australia as a subtropical cyclone.

Tropical Cyclone Seth Spins Northeast of Brisbane

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.

Tropical Cyclone Seth Forms over Coral Sea

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.