Tropical Cyclone Herman Strengthens Northwest of Australia

Tropical Cyclone Herman strengthened over the South Indian Ocean northwest of Australia during Wednesday night. At 5:00 a.m. EDT on Thursday the center of Tropical Cyclone Herman was located at latitude 15.5°S and longitude 105.1°E which put it about 570 miles (920 km) east-southeast of Cocos Islands. Herman was moving toward the southeast at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 985 mb.

Tropical Cyclone Herman strengthened over the South Indian Ocean northwest of Australia during the past 24 hours. The inner end of a rainband wrapped completely around the center of Herman’s circulation. A small circular eye formed at the center of circulation. A ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Herman. Storms near the center generated upper level divergence that pumped mass away to the southeast of the tropical cyclone. Winds to tropical storm force extended out 65 miles (105 km) from the center of Herman’s circulation.

Tropical Cyclone Herman will move through an environment that will become unfavorable for intensification during the next 24 hours. Herman will move over water where the Sea Surface Temperatures are near 28˚C. However, an upper level trough will approach Tropical Cyclone Herman from the west. The upper level trough will produce northwesterly winds that will get stronger during the next 24 hours. Those stronger winds will blow toward the top of Herman’s circulation and the vertical wind shear will increase. More vertical wind shear will cause Tropical Cyclone Herman to weaken.

The upper level trough will steer Tropical Cyclone Herman toward the southeast during the next 24 hours. On its anticipated track Tropical Cyclone Herman will move farther away from Cocos Islands. When the stronger vertical wind shear causes Herman to weaken, it will be steered by the winds closer to the surface. Those winds will steer Tropical Cyclone Herman toward the west during the end of the week and the weekend.