Tropical Cyclone Chido rapidly intensified to the equivalent of a major hurricane over the South Indian Ocean east of northern Madagascar on Wednesday afternoon. At 4:00 p.m. EST on Wednesday the center of Tropical Cyclone Chido was located at latitude 10.4°S and longitude 56.3°E which put the center about 490 miles (790 km) east of Antsiranana, Madascar. Chido was moving toward the west at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 165 m.p.h. (265 km/h). The minimum surface pressure was 945 mb.
Tropical Cyclone Chido rapidly intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Wednesday afternoon. A small circular eye with a diameter of 7 miles (11 km) was at the center of Chido’s circulation. 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 Chido. Storms near the core of Chido generated strong upper level divergence that pumped large quantities of mass away from the tropical cyclone. The removal of mass large amounts of mass caused the surface pressure to decrease rapidly.
The circulation around Tropical Cyclone Chido was small. Winds to hurricane/typhoon force extended out 20 miles (30 km) from the center of Chido’s circulation. Winds to tropical storm force extended out 60 miles in from the center of Tropical Cyclone Chido.
The Hurricane Intensity Index (HII) for Tropical Cyclone Chido is 28.3. The Hurricane Size Index (HSI) is 7.0 and the Hurricane Wind Intensity Size Index (HWISI) is 35.3. Tropical Cyclone Chido is similar in size and intensity to Hurricane Charley when Charley made landfall in southwest Florida in 2004.
Tropical Cyclone Chido will move through an environment favorable for intensification during the next 24 hours. Chido will move over water where where the Sea Surface Temperatures are near 28°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 Chido could continue to intensify during the next 24 hours. However, if the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. If concentric eyewalls form, then an eyewall replacement cycle would cause Chido to weaken.
Tropical Cyclone Chido will move around the northern side of a high pressure system over the South Indian Ocean. The high pressure system will steer Chido toward the west during the next 24 hours. On its anticipated track, Tropical Cyclone Chido will move toward northern Madagascar. The center of Chido will reach northern Madagascar on Friday.
Tropical Cyclone Chido will bring strong winds and heavy rain to northern Madagascar. Chido is likely to be the equivalent of a major hurricane when it hits Madagascar. Heavy rain is likely to cause flash floods in some locations. Tropical Cyclone Chido could also cause a storm surge of up to 13 feet (4 meters ) along parts of the coast of northern Madagascar.