Tropical Cyclone Darian Spins over South Indian Ocean

Tropical Cyclone Darian was spinning over the South Indian Ocean on Saturday night. At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Darian was located at latitude 14.8°S and longitude 84.8°E which put it about 970 miles (1565 km) east-southeast of Diego Garcia. Darian was moving toward the south-southeast at 13 m.p.h. (20 km/h). The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 964 mb.

Tropical Cyclone Darian weakened as it spun over the South Indian Ocean on Saturday night. A break developed in the northeastern part of the ring of thunderstorms around the center of Darian’s circulation. The distribution of thunderstorms also became asymmetrical. Many of the thunderstorms were occurring in bands in the western half of Tropical Cyclone Darian. Bands in the eastern half of Darian consisted primarily of showers and lower clouds. Storms near the center of circulation still generated upper level divergence that pumped mass away to the south of the tropical cyclone.

The circulation around Tropical Cyclone Darian was still well organized. Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of Darian. Winds to tropical storm force extended out 160 miles (260 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Darian was 17.8. The Hurricane Size Index (HSI) was 18.2 and the Hurricane Wind Intensity Size Index (HWISI) was 36.0.

Tropical Cyclone Darian will move through an environment unfavorable for intensification during the next 24 hours. Darian will move over water where the Sea Surface Temperatures are near 27˚C. It will move under the western part of an upper level ridge centered west of Australia. The ridge will produce northeasterly winds that will blow toward the top of Darian’s circulation. Those winds will cause vertical wind shear. The wind shear may already be contributing to the asymmetrical distribution of thunderstorms. The wind shear is likely to be strong enough to cause Tropical Cyclone Darian to weaken during the next 24hours.

The upper level ridge west of Australia will steer Tropical Cyclone Darian toward the south during the next 24 hours. On its anticipated track, Tropical Cyclone Darian will move farther away from Diego Garcia.