Tropical Cyclone Grant rapidly intensified to the equivalent of a major hurricane over the South Indian Ocean southeast of Diego Garcia on Sunday. At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Grant was located at latitude 13.6°S and longitude 82.0°E which put the center about 810 miles (1305 km) southeast of Diego Garcia. Grant was moving toward the west-southwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 957 mb.
Tropical Cyclone Grant rapidly intensified to the equivalent of a major hurricane on Sunday. The inner end of a rainband wrapped around the center of Grant’s circulation. A small circular eye with a diameter of 10 miles (16 km) formed at the center of Tropical Cyclone 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 caused the surface pressure to decrease.
The circulation around Tropical Cyclone Grant was 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 60 miles (95 km) from the center of Tropical Cyclone Grant.
Tropical Cyclone Grant will move through an environment favorable 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 middle of an upper level ridge over the South Indian Ocean. The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear. Tropical Cyclone Grant is likely to continue to intensify during the next 24 hours unless the inner end of a rainband wraps around the existing eye and eyewall. If concentric eyewalls form, then Grant will weaken.
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 pass south of Diego Garcia in 48 hours.
Elsewhere over the South Indian Ocean, Tropical Cyclone Hayley was intensifying as it moved toward the coast of Western Australia. At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Hayley was located at latitude 15.0°S and longitude 119.5°E which put the center about 290 miles (465 km) northwest of Broome, Australia. Hayley was moving toward the south at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 988 mb.
The Australian Bureau of Meteorology issued a Warning for the portion of the coast from north of Broome to Cape Leveque.
The Australian Bureau of Meteorology issued a Watch for the zone from Broome to Kuri Bay. The Watch included Derby and Cockatoo Island.
