Tropical Cyclone Lili formed over the Timor Sea on Thursday. At 11:00 a.m. EDT on Thursday the center of Tropical Cyclone Lili was located at latitude 9.1°S and longitude 128.8°E which put it about 100 miles (160 km) southeast of Tutuala, East Timor. Lili was moving toward the south-southwest at 5 m.p.h. (8 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 991 mb.
The circulation around a low pressure system over the Timor Sea exhibited more organization on Thursday and the system was designated as Tropical Cyclone Lili. Several bands of showers and thunderstorms began to wrap around the low level center of circulation. Additional bands of showers and thunderstorms began to develop around the periphery of the circulation. Storms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical cyclone. The circulation around Tropical Cyclone Lili was relatively small. Winds to tropical storm force only extended out about 60 miles (95 km) from the center of circulation.
Tropical Cyclone Lili will move through an environment favorable for intensification during the next 12 to 24 hours. Lili will move over water where the Sea Surface Temperature is near 29°C. It will move under the western portion of an upper level ridge. Tropical Cyclone Lili will move through an area where the upper level winds are not too strong during the next 12 to 24 hours and there will not be a lot of vertical wind shear. Lili could intensify during that period. Tropical Cyclone Lili will move closer to the western end of the ridge in about 24 hours. There are strong northerly winds blowing around the western end of the ridge and there will be more vertical wind shear. If the shear increases, then the circulation around Lili is likely to weaken.
Tropical Cyclone Lili will move north of a subtropical ridge. The ridge is likely to steer Lili more toward the west. On its anticipated track Tropical Cyclone Lili could reach East Timor in about 36 hours. Lili will bring gusty winds, but heavy rain and flooding are greater risks. An alternative forecast scenario is possible. If the vertical wind shear is not too strong and the vertical structure of Tropical Cyclone Lili remains intact, the upper level ridge could steer Lili more toward the south. In that case Tropical Cyclone Lili could bring rain to Western Australia.