Tropical Cyclone Darian strengthened back to the equivalent of a major hurricane over the South Indian Ocean southeast of Diego Garcia on Monday. At 10:00 a.m. EST on Monday the center of Tropical Cyclone Darian was located at latitude 16.9°S and longitude 84.5°E which put it about 1060 miles (1710 km) southeast of Diego Garcia. Darian was moving toward the southwest at 4 m.p.h. (6 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 947 mb.
After completing several eyewall replacement cycles during the past 36 hours, Tropical Cyclone Darian strengthened back to the equivalent of a major hurricane over the South Indian Ocean far to the southeast of Diego Garcia. A circular eye with a diameter of 35 miles (55 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.
The completed eyewall replacements cycles increased the size of the circulation around Tropical Cyclone Darian. Winds to hurricane/typhoon force extended out 50 miles (80 km) from the center of Darian. Winds to tropical storm force extended out 195 miles (305 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Darian was 23.6. The Hurricane Size Index (HSI) was 19.4 and the Hurricane Wind Intensity Size Index (HWISI) was 43.0.
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. If the inner end of a rainband wraps around the core of Tropical Cyclone Darian, then another eyewall replacement cycle could begin. A new eyewall replacement cycle would cause Darian to weaken again. Tropical Cyclone Darian will move over cooler water later this week, which is likely to cause a steadier weakening trend.
Tropical Cyclone Darian will move around the northwestern part of a high pressure system over the South Indian Ocean. The high pressure system will steer Darian toward the southwest during the next few days. On its anticipated track, Tropical Cyclone Darian will pass far to the south of Diego Garcia. Darian could be southeast of Rodrigues in three days.