Tropical Cyclone Hidaya Nears Tanzania

Tropical Cyclone Hidaya neared the coast of Tanzania on Friday night. At 11:00 p.m. EDT on Friday the center of Tropical Cyclone Hidaya was located at latitude 7.8°S and longitude 40.5°E which put it about 125 miles (200 km) southeast of the Dar es Salaam, Tanzania. Hidaya was moving toward the west-northwest 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.

Tropical Cyclone Hidaya started to weaken on Friday as it approached the coast of Tanzania. Westerly winds blowing around the northern side of Hidaya’s circulation pulled drier air that was over Africa into the tropical cyclone. The drier air circulated around the northern and eastern parts of Tropical Cyclone Hidaya. When the drier air reached rainbands in those parts of Hidaya’s circulation, some of the thunderstorms weakened. When the thunderstorms weakened, the upper level divergence decreased. Less mass was pumped away from the tropical cyclone and the surface pressure started to increase.

Even though Tropical Cyclone Hidaya started to weaken, its circulation was still well organized. A small circular eye was evident at the center of Hidaya’s circulation in infrared satellite images. The eye was surrounded by a narrow ring of thunderstorms and the strongest winds were still occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Hidaya. Winds to tropical storm force extended out 100 miles (160 km) from the center of Hidaya’s circulation.

Tropical Cyclone Hidaya will move through an environment that will become more unfavorable for intensification during the next 12 hours. Hidaya 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. However, Tropical Cyclone Hidaya will pull more drier air that is currently over Africa into its circulation as it moves closer to the coast of Tanzania. The drier air is likely to cause more thunderstorms to weaken, which will further decrease the upper level divergence. The surface pressure will continue to increase as the upper level divergence decreases. Tropical Cyclone Hidaya is likely to continue to weaken during the next 12 hours.

Tropical Cyclone Hidaya will move around the northern side of a high pressure system over the South Indian Ocean. The high pressure system will steer the Hidaya toward the northwest during the next 24 hours. On its anticipated track Tropical Cyclone Hidaya will approach the coast of Tanzania near Dar es Salaam in 12 hours. Hidaya will bring strong winds and locally heavy rain to eastern Tanzania. Heavy rain could cause flash floods in some locations. Hidaya will also bring gusty winds and locally heavy rain to Zanzibar and Mafia Island. Tropical Cyclone Hidaya could also produce a storm surge of up to 7 feet (2 meters) along the coast of Tanzania.