Tropical Cyclone 11S formed east of the northern tip of Madagascar on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone 11S was located at latitude 13.2°S and longitude 54.3°E which put it about 535 miles (865 km) north of St. Denis, La Reunion.  It was moving toward the southeast at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 996 mb.

A distinct center of circulation finally developed on Friday in an area of thunderstorms that had been stationary northeast of Madagascar.  A primary band of storms wrapped around the northern side of the center of circulation and then storms began to develop near the center.  Additional bands of showers and thunderstorms were revolving around the core of the circulation and the structure of the circulation was organized enough to be classified as a tropical cyclone.  Storms near the center of circulation began to generate upper level divergence which was pumping mass away from the tropical cyclone.

Tropical Cyclone 11S will be moving through an environment that is very favorable for intensification.  It will move over water where the Sea Surface Temperature is near 30°C.  Tropical Cyclone 11S is located under an upper level ridge and the upper level winds are weak.  There is little vertical wind shear to inhibit intensification.  Tropical Cyclone 11S will intensify during the weekend and it is likely to intensify rapidly at times.  Tropical Cyclone 11S could strengthen into the equivalent of a major hurricane during the next two or three days.

Tropical Cyclone 11S and its precursor have been in an area where the steering winds were weak.  A subtropical ridge located to the east of the tropical cyclone is forecast to strengthen.  The ridge will steer Tropical Cyclone 11S toward the south-southwest.  Early model guidance suggests that the center of the tropical cyclone will move between Madagascar and La Reunion, but there is still uncertainty in the future track of the system.