Summary
The unnamed tropical cyclone 09U was deemed to have briefly reached tropical cyclone intensity upon reanalysis, over open waters of the Indian Ocean on 10 January.
A tropical low formed to the south of Christmas Island on 8 January 2025. In the days preceding the formation of a closed circulation there was a trough lying through Indonesia, and 09U likely eventuated from this elongated area of rotation. There were no climate drivers aiding formation and the Madden-Julian Oscillation (MJO) was in a supressed phase.
Tropical low 09U initially moved in a general westward direction, then made a turn towards the south on 9 January 2025. On 10 January 09U intensified. During operations gales were analysed in southern quadrants, but on post event review gale force winds are analysed to extend into all quadrants for a period of 6-12 hours, classifying 09U as a category 1 tropical cyclone from 0000 UTC on 10 January. By 1200 UTC 10 January 09U gales contracted to the southern quadrants, and by 0000 UTC on 11 January winds were estimated below gale force.
There were no impacts to island or coastal communities associated with 09U.
For more information see the Unnamed 09U Report (doc).
Track and Intensity (Time in UTC (AWST-8 hours))
