Summary
Much of the genesis and track of Vivienne is open conjecture as the system formed to the west of Christmas Island in a data-sparse area during the period between the failure of GMS-2 and the relocation of GMS-1.
The initial low formed at about 9°S 110°E on 23 January and gradually deepened whilst moving on a southerly track before coming under the influence of upper-level easterly winds. Cyclonic intensity was reached at about 1600 UTC 23 January. Vivienne turned onto a west-southwest track at about 1200 UTC 24 January and continued to deepen and was classified as a severe cyclone at 0600 UTC 27 January just before it crossed into the Mauritius forecasting area with an estimated central pressure of 975 hPa at 1200 UTC 27 January. Weakening occurred following its movement into the Mauritius region.
Track and intensity
