Alenga

History

Severe Tropical Cyclone Alenga developed from a tropical low that TCWC Perth and TCWC Jakarta began monitoring on 3 December 2011, located approximately 1,220 kilometres southwest of Jakarta, Indonesia. The system initially moved southeast before crossing out of the Australian region into the South-West Indian Ocean, where it was named Alenga by the Mauritius Meteorological Service on 5 December. It reached an initial peak of 100 km/h on 10-minute sustained winds before weakening slightly, then re-intensified as it curved back into the Australian region around 7 December.

At its peak on 8 December, TCWC Perth classified Alenga as a Category 3 Severe Tropical Cyclone with 10-minute sustained winds of 150 km/h. The JTWC recorded even stronger 1-minute winds of 175 km/h at peak intensity. Alenga did not make landfall, instead moving into an area of increasing vertical wind shear that caused rapid weakening. Convection diminished and the low-level circulation centre became elongated, leading TCWC Perth to downgrade the system to a tropical low on 9 December. The remnants were tracked for a further three days before being dropped on 12 December. Despite not crossing the coast as a cyclone, the system's remnants brought severe storms to the Perth metropolitan area on 12 and 13 December.

Sources: Bureau of Meteorology report Wikipedia