Ambali - first cyclone of 2019-2020 season

Tropical Cyclone AMBALI

On 6 December, at 16h00 Mauritius Time (MT), tropical cyclone Ambali, the first of the 2019-2020 cyclone season in South West Indian Ocean, was located at 11.0°S 62.3°E. It was moving SSW 10 km/h. It was some 1100km NNE of Mauritius.

The name was given by Malawi.

Another area of convection formed along the same trough between the Seychelles and the Chagos Archipelago in early December.

On 3 December, the system organized quickly, attaining formative rain bands around a coalescing centre of circulation. At 10:00 Mauritius Time, the system was classified as a Zone of Disturbed Weather.

On 4 December, the system was upgraded to a tropical depression following a significant increase in convection near its centre.  Steered by a high-pressure area centred over the southern Indian Ocean, the tropical depression moved south. The quick organization continued into 5 December, and the Moderate Tropical Storm was named Ambali. It intensified into a Severe Tropical Storm a few hours later. Buoyed by a highly favourable environment with waters between 29–30 °C, explosive intensification ensued, accompanied by the formation of an eye.

At 22h00 on 5 December, Ambali was upgraded into an intense tropical cyclone status following a sharp 75 km/h increase in the storm's winds in 3 hours. The cyclone was highly compact, with a distinct eye 15 km in diameter surrounded by cold cloud tops.

Six hours later, Ambali was reclassified as a Very Intense Tropical Cyclone (Category 4), the highest rating on the intensity scale and the first in the basin since Fantala in 2016. The maximum 10-minute sustained winds of 220 km/h and a minimum pressure of 930 hPa were estimated.

Early on 6 December at the time of peak intensity, the cyclone's eye had contracted further to a diameter of 9 km. Ambali marked the fastest 24-hour intensification recorded in the Southern Hemisphere since 1980. A gradual weakening trend soon succeeded the rapid intensification episode as indicated by a clouding-over of the small eye.