BESSI

History

Tropical Cyclone Bessi–Bako began as an area of convection that developed to the southwest of Sumatra on 25 November 2001. As the disturbance became better organised, the Joint Typhoon Warning Center issued a Tropical Cyclone Formation Alert on 26 November, and the Tropical Cyclone Warning Centre in Perth began issuing gale warnings in anticipation of further development. Moderate vertical wind shear initially held the system back, prompting a second formation alert on 27 November. Later that day the JTWC began warnings on the system as Tropical Cyclone 05S, while Perth named it Tropical Cyclone Bessi, at which point the centre lay roughly 650 km northwest of the Cocos (Keeling) Islands.

Bessi tracked westwards at first, but a mid-level trough eroded the subtropical ridge steering it and the cyclone turned southwards. It reached an initial peak of 110 km/h on 28 November while about 695 km west-northwest of the Cocos Islands, before moving into a region of stronger shear and weakening. Bessi drifted south-southeast on 29 November, then curved back to the west on 30 November with winds down to about 75 km/h. It then crossed west of 90°E into the South-West Indian Ocean basin, where it was renamed Tropical Storm Bako and subsequently attained an estimated peak of 65 knots. The cyclone remained over open water throughout its life in the Australian region.

Sources: Bureau of Meteorology report Wikipedia