Tropical Cyclone Darian Rapidly Intensifies to Equivalent of a Major Hurricane

Tropical Cyclone Darian rapidly intensified to the equivalent of a major hurricane over the South Indian Ocean east-southeast of Diego Garcia on Tuesday. At 4:00 a.m. EST on Tuesday the center of Tropical Cyclone Darian was located at latitude 14.0°S and longitude 92.7°E which put it about 1255 miles (2355 km) east-southeast of Diego Garcia. Darian was moving toward the southwest at 6 m.p.h. (10 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 946 mb.

Tropical Cyclone Darian continued to intensify rapidly on Tuesday. A circular eye with a diameter of 25 miles (40 km) was at the center of Darian’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Darian. Storms near the core generated upper level divergence that pumped mass away from the tropical cyclone in all directions.

The size of Tropical Cyclone Darian increased as it intensified rapidly. Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of Darian. Winds to tropical storm force extended out 165 miles (265 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Darian was 23.6. The Hurricane Size Index (HSI) was 16.3 and the Hurricane Wind Intensity Size Index (HWISI) was 39.9.

Tropical Cyclone Darian will move through an environment favorable for a strong tropical cyclone during the next 24 hours. Darian will move over water where the Sea Surface Temperatures are near 27˚C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Tropical Cyclone Darian could continue to intensify during the next 24 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then an eyewall replace cycle could begin. An eyewall replacement cycle would cause Darian to weaken temporarily.

Tropical Cyclone Darian will move around the northern part of a subtropical high pressure system north of the South Indian Ocean. The high pressure system will steer Darian toward the west during the next few days. On its anticipated track Tropical Cyclone Darian will be southeast of Diego Garcia later this week.