A tropical low developed near West Timor on Saturday. At 8:00 p.m. EDT on Saturday the center of the tropical low was located at latitude 10.6°S and longitude 123.6°E which put it about 30 miles (50 km) west of Kupang, Indonesia. The tropical low was nearly stationary. The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1003 mb.
An area of low pressure near West Timor exhibited more organization on Saturday and the Australian Bureau of Meteorology classified the system as a tropical low. Visible and microwave satellite images showed a distinct low level center of circulation. More thunderstorms formed near the center of the tropical low. Bands of showers and thunderstorms were revolving around the center of circulation. Storms near the center began to generate upper level divergence that pumped mass away from the tropical low.
The tropical low will move through an environment favorable for intensification during the next several days. The tropical low will move over water where the Sea Surface Temperatures will be near 30°C. It will move under the axis of an upper level ridge. The winds are weak near the axis of the ridge and there will be little vertical wind shear. The tropical low is likely to intensify into the equivalent of a tropical storm during the next 24 hours. It could strengthen into the equivalent of a hurricane/typhoon by early next week.
The tropical low will be in an area where the steering winds are weak during the next 24 hours. It will remain near West Timor during that time. Thunderstorms in rainbands will drop locally heavy rain and flash floods could occur. A high pressure system over Australia will begin to steer the tropical low toward the southwest in a day or so. On its anticipated track the system will remain northwest of Western Australia during the next few days.
Tropical Cyclone Berguitta intensified into the equivalent of a hurricane/typhoon on Sunday. At 10:00 p.m. EST on Sunday the center of Tropical Cyclone Berguitta was located at latitude 17.8°S and longitude 63.1°E which put it about 415 miles (670 km) east-northeast of Port Louis, Mauritius. Berguitta was nearly stationary. The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h). The minimum surface pressure was 985 mb.
The circulation of Tropical Cyclone Berguitta continued to get better organized on Sunday. An eye appeared intermittently at the center of circulation. The eye was surrounded by an elliptical ring of thunderstorms and the strongest winds were occurring in those storms. Bands of showers and thunderstorms were revolving around the core of the circulation. Storms near the center of Berguitta were generating upper level divergence which was pumping mass away from the center of circulation.
Tropical Cyclone Berguitta will continue to move through an environment favorable for intensification during the next several days. Berguitta will move over water where the Sea Surface Temperature is near 28°C. The upper level winds are weak and there is little vertical wind shear. Tropical Cyclone Berguitta will continue to strengthen and it could intensify into the equivalent of a major hurricane.
Tropical Cyclone Berguitta is moving in a region where the steering winds are weak. Berguitta moved little on Sunday. A subtropical ridge south of Berguitta is forecast to steer the tropical cyclone slowly westward during the next 24 to 48 hours. Berguitta will near the western end of the ridge in about two days and it is likely to move toward the southwest after that time. On its anticipated track Tropical Cyclone Berguitta could reach Mauritius within 72 hours.
The core of Tropical Cyclone Berguitta could move very close to Mauritius and La Reunion. Berguitta could be the equivalent of a major hurricane at that time. It has the potential to cause major wind damage, a storm surge, heavy rain and floods.
Elsewhere over the South Indian Ocean microwave images of Invest 99S depicted a structure that looked very much like a tropical cyclone. At 10:00 p.m. EST on Sunday the center of Invest 99S was centered at latitude 15.1°S and longitude 41.6°E which put it about 75 miles (120 km) east of Lumbo, Mozambique. Microwave satellite images showed a clear area at the center of circulation surrounded by broken ring of showers and thunderstorms. A primary rainband wrapped around the eastern side of the circulation and secondary bands of showers and thunderstorms existed in all quadrants of the circulation. However, no official government agency is classifying the system as a tropical cyclone at the current time.