Tropical Cyclone Herold formed over the South Indian Ocean east of Madagascar on Friday. At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Herold was located at latitude 14.8°S and longitude 51.9°E which put it about 510 miles (825 km) northwest of Port Louis, Mauritius. Herold was moving toward the southwest at 4 m.p.h. (6 km/h). The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h). The minimum surface pressure was 996 mb.
A distinct low level center of circulation organized quickly in an area of thunderstorms east of Madagascar on Friday and the system was designated as Tropical Cyclone Herold. The circulation around Herold was still organizing and the distribution of thunderstorms was asymmetrical. Many of the stronger thunderstorms developed in bands northwest of the center of circulation. Bands in other parts of the circulation consisted primarily of showers and lower clouds. Thunderstorms northwest of the center of Herold were generating upper level divergence which was pumping mass away from the tropical cyclone. Winds to tropical storm force extended out 85 miles (135 km) from the center of circulation.
Tropical Cyclone Herold will move through an environment that will become increasingly favorable for intensification during the next several days. Herold is currently under a small upper level ridge centered near Madagascar. The ridge is producing southeasterly winds which are blowing toward the top of the circulation. Those winds are causing some vertical wind shear and they are probably the reason for the asymmetrical distribution of thunderstorms. However, Tropical Cyclone Herold will move into a region where the upper level winds are weaker during the weekend. Herold will move over water where the Sea Surface Temperature is near 29°C during that time period. Tropical Cyclone Herold will intensify during the next several days and it could intensify rapidly once the inner core becomes better organized. Herold is likely to intensify into the equivalent of a hurricane/typhoon during the next 24 hours. It could strengthen into the equivalent of a major hurricane during the next 72 hours.
Tropical Cyclone Herold is currently in an area where the steering currents are weak. A subtropical high pressure system over the South Indian Ocean will strengthen during the next several days. The western end of the subtropical high will start to steer Herold toward the east-southeast during the weekend. On its anticipated track the center of Tropical Cyclone Herold could be northwest of Mauritius in less than 72 hours. Herold is likely to be the equivalent of a major hurricane at that time.