A low level circulation developed enough organization on the eastern side of a cluster of thunderstorms over the Mozambique Channel to be classified as a tropical cyclone on Thursday.  At 11:00 p.m. EST on Thursday the center of Tropical Cyclone 15S was located at latitude 16.6°S and longitude 42.3° which put it about 110 miles east-southeast of Mogincual, Mozambique and about 200 miles northwest of Maintirano, Madagascar.  It was moving toward the south-southeast at 5 m.p.h.  The maximum sustained wind speed was 40 m.p.h. and there were wind gusts to 50 m.p.h.  The minimum surface pressure was 996 mb.

Southeasterly winds in the upper levels are creating vertical wind shear and most of the stronger thunderstorms are on the western side of the center of circulation.  However, the tropical cyclone is over warm Sea Surface Temperatures and some intensification is possible.  If the upper level winds decrease, the more rapid intensification could occur.  A gradual intensification seems more likely over the short term.

A subtropical ridge of high pressure to the east of the tropical cyclone is steering it slowly to the south.  It is likely to move into a region of weak steering winds  between that ridge of high pressure and another ridge farther to the west.  As a result, the tropical cyclone could move slowly and erratically and even become stationary at times during the next day or two.  Eventually, a third ridge of high pressure is expected to develop to the north of the system and push it westward toward Madagascar.

The tropical cyclone could be a strong tropical storm or near hurricane intensity when it reaches Madagascar.  Some wind damage is possible, but the biggest threat appears to be from locally heavy rainfall and flooding.