Tropical Cyclone Grant passed south of Diego Garcia on Tuesday night. At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone Grant was located at latitude 15.8°S and longitude 69.2°E which put the center about 625 miles (1005 km) south-southwest of Diego Garcia. Grant was moving toward the west at 26 m.p.h. (43 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 958 mb.
Tropical Cyclone Grant weakened as it passed south of Diego Garcia on Tuesday night. An eye was no longer visible on satellite images of Grant. Bands of showers and thunderstorms were revolving around the center of Grant’s circulation. Storms near the center of Grant generated upper level divergence that pumped mass away from the tropical cyclone. The removal of mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere. So, the surface pressure was increasing.
The circulation around Tropical Cyclone Grant was still very small. Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Grant’s circulation. Winds to tropical storm force extended out 70 miles (110 km) from the center of Tropical Cyclone Grant.
The Hurricane Intensity Index (HII) for Tropical Cyclone Grant was 20.6. The Hurricane Size Index (HSI) was 8.9 and the Hurricane Wind Intensity Size Index (HWISI) was 29.5.
Tropical Cyclone Grant will move through an environment unfavorable for intensification during the next 24 hours. Grant will move over water where the Sea Surface Temperatures are near 28°C. It will move under the northern part of an upper level ridge over the South Indian Ocean. The upper level ridge will produce easterly winds that will blow toward the top of Grant’s circulation. Those winds will cause moderate vertical wind shear. The moderate wind shear will cause Tropical Cyclone Grant to continue to weaken during the next 24 hours.
Tropical Cyclone Grant will move around the northern side of a high pressure system over the South Indian Ocean. The high pressure system will steer Grant toward the west during the next 24 hours. On its anticipated track, Tropical Cyclone Grant will move farther away from Diego Garcia. Grant will pass north of Rodrigues in 48 hours.
