Summary
Tropical Cyclone Odette reached tropical cyclone intensity for two short periods over the Indian Ocean to the north-west of the Western Australian mainland, and whilst it threatened the far western parts of the Pilbara, it did not have any significant impacts on the Western Australian mainland.
A tropical low formed within the monsoon trough well to the west of Christmas Island on 3 April and began tracking south-east. On 4 April it continued to develop and started to move towards the south. Gales (ten-minute mean winds of 34 kn or greater) developed on the eastern side of the low, however the system remained classified as a tropical low as the gales failed to extend more than halfway around the centre. Later on 4 April, the gales moved around into the southern semicircle of the low, but remained less than half way around the centre.
On 5 April environmental conditions became more conducive to development. In post analysis it has been determined that gales extended around the entirety of the system at 1200 UTC and 1800 UTC on 5 April. Although it was not operationally named during this time, it has now been classified as a tropical cyclone for this short period.
Gales once again become confined to the southern semicircle of the system at 0000 UTC 6 April, and it then remained slow moving for the next 48 hours. On 8 April, the system started to move north-east as Tropical Cyclone Seroja approached from the east and began to interact as per the Fujiwhara effect (see http://media.bom.gov.au/social/blog/2571/when-cyclones-collide-the-fujiwhara-effect/ ). At the same time conditions again became conducive for development, and it redeveloped into a tropical cyclone at 1800 UTC 8 April (operationally, the system was named Tropical Cyclone Odette at 0000 UTC 9 April). In part due to the rapid eastward motion during its interaction with Tropical Cyclone Seroja enhancing the winds on the northern side of the system, Odette reached category 2 intensity (with ten-minute mean winds of 50 kn) at 0000 UTC 9 April.
As the low transitioned to the south-east and then south conditions rapidly deteriorated and Tropical Cyclone Odette weakened. Due to the fast southward movement on 10 April, gale force winds were still observed to the east of the low as it passed well to the west of the Northwest Cape.
Heavy rainfall was observed at Christmas Island in the overnight period from 3 April into 4 April whilst the tropical low was in the vicinity, with 115.6 millimetres recorded to 9 am 4 April. Although Tropical Cyclone Odette did not result in any damage, it was a notable system due to its Fujiwara interaction with Severe Tropical Cyclone Seroja, which is a rarely observed phenomenon for Australian tropical systems.
Tropical Cyclone Odette was the 8th tropical cyclone in the Australian region for the 2020/2021 season.
For more information see the TC Odette report (pdf).
Track and Intensity
