Tropical Cyclone Ancha Forms Southeast of Diego Garcia

Tropical Cyclone Ancha formed over the South Indian Ocean southeast of Diego Garcia on Tuesday night.  At 11:00 p.m. EDT on Wednesday the center of Tropical Cyclone Ancha was located at latitude 11.7°S and longitude 74.2°E which put the center about 335 miles (540 km) south-southeast of Diego Garcia.  Ancha was moving toward the south-southwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 994 mb.

A low pressure system over the South Indian Ocean southeast of Diego Garcia intensified on Tuesday night and Meteo France la Reunion designated the system as Tropical Cyclone Ancha.  The circulation around Tropical Cyclone Ancha exhibited more organization on Wednesday morning.  The inner end of a rainband wrapped around the southern side of the center of Ancha’s circulation.  Even though the circulation around Tropical Cyclone Ancha exhibited more organization, the distribution of thunderstorms was still asymmetrical.  Thunderstorms were occurring in bands in the eastern and southern parts of Ancha’s circulation.  Bands in the northern and western parts of the circulation consisted primarily of showers and lower clouds.  Storms near the center of Ancha generated upper level divergence that pumped mass away to the east of the tropical cyclone.

The circulation around Tropical Cyclone Ancha was small.  Winds to tropical storm force only extended out 50 miles (80 km) from the center of Ancha’s circulation.

Tropical Cyclone Ancha will move through an environment unfavorable for intensification during the next 24 hours.  Ancha will move over water where the Sea Surface Temperatures are near 24°C.  It will move under the northern part of an upper level trough over the South Indian Ocean.  The upper level trough will produce southwesterly winds that will blow toward the top of Ancha’s circulation.  Those winds will cause moderate vertical wind shear.  The combination of cooler water and moderate vertical wind shear will cause Tropical Cyclone Ancha to weaken during the next 24 hours.

Tropical Cyclone Ancha will move around the western end of high pressure system over the South Indian Ocean.  The high pressure system will steer Ancha toward the southwest during the next 24 hours.  On its anticipated track, Tropical Cyclone Ancha will pass well to the south of Diego Garcia.