Powerful Tropical Cyclone Cilida Strengthens to Equivalent of Cat. 4 Hurricane

Powerful Tropical Cyclone Cilida strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Cilida was located at latitude 15.9°S and longitude 57.8°E which put it about 310 miles (505 km) north of Port Louis, Mauritius.  Cilida was moving toward the south at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 931 mb.

The circulation of Tropical Cyclone Cilida was very well organized.  A circular eye was at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Cilida.  Storms around the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

The circulation around Tropical Cyclone Cilida was relatively small.  Winds to hurricane/typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force only extended out about 95 miles (155 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Cilida was 31.6.  The Hurricane Size Index (HSI) was 11.0 and the Hurricane Wind Intensity Size Index (HWISI) was 42.6.

Tropical Cyclone Cilida may have peaked in intensity, but it will move through an environment capable of supporting a strong tropical cyclone for another 24 to 36 hours.  Cilida will move over water where the Sea Surface Temperature is near 28°C for about another 24 hours.  Then it will start to move over colder waters.  Tropical Cyclone Cilida will move toward the upper level westerly winds in the middle latitudes and the vertical wind shear will increase in about 36 hours.  When Cilida moves over colder water and under stronger upper level winds, it will weaken more quickly.

Tropical Cyclone Cilida is moving around the western end of a subtropical ridge over the South Indian Ocean.  The ridge will start to steer Cilida toward the southeast on Saturday.  On its anticipated track, the center of Tropical Cyclone Cilida could be a little northeast of Mauritius in about 24 hours.  It will still be a powerful tropical cyclone at that time.

Elsewhere over the South Indian Ocean, Tropical Cyclone Kenanga continued to weaken well to the southeast of Diego Garcia.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Kenanga was located at latitude 16.3°S and longitude 78.5°E which put it about 760 miles (1225 km) southeast of Diego Garcia.  Kenanga was moving toward the west 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 982 mb.