Tropical Cyclone Djoungou Rapidly Intensifies to Equivalent of a Major Hurricane

Tropical Cyclone Djoungou rapidly intensified to the equivalent of a major hurricane over the South Indian Ocean south of Diego Garcia on Saturday. At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Djoungou was located at latitude 17.1°S and longitude 73.3°E which put it about 660 miles (1065 km) south of Diego Garcia. Djoungou was moving toward the east-southeast at 22 m.p.h. (35 km/h). The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (235 km/h). The minimum surface pressure was 960 mb.

A small circular eye formed at the center of Tropical Cyclone Djoungou as it rapidly intensified on Saturday. The eye was surrounded by a ring of 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 Djoungou. Storms near the core generated strong upper level divergence that pumped large quantities of mass away from the tropical cyclone. The removal of large amounts of mass caused the surface pressure to decrease rapidly.

The circulation around Tropical Cyclone Djoungou also became more symmetrical when Djoungou rapidly intensified. Winds to hurricane/typhoon force extended out 50 miles (80 km) from the center of Djoungou’s circulation. Winds to tropical storm force extended out 185 miles (295 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Djoungou was 20.6. The Hurricane Size Index (HSI) was 20.2 and the Hurricane Wind Intensity Size Index (HWISI) was 40.8.

Tropical Cyclone Djoungou will move through an environment favorable for intensification during the next 24 hours. Djoungou will move over water where the Sea Surface Temperatures are near 29°C. It will move under the axis of an upper level ridge over the South Indian Ocean. The upper level winds are weak near the axis of the ridge and there will be little vertical wind shear. Tropical Cyclone Djoungou is likely to intensify during the next 24 hours. However, Djoungou could start to weaken if the inner end of a rainband wraps around the existing eye and eyewall and concentric eyewalls form.

Tropical Cyclone Djoungou will move around the southern side of a high pressure system over the South Indian Ocean. The high pressure system will steer Djoungou toward the east-southeast during the next 24 hours. On its anticipated track, Tropical Cyclone Djoungou will move farther southeast of Diego Garcia.