Summer 2019-2020 Outlook : extreme weather event is expected 

The summer outlook for 2019-2020 was published earlier this week. According to the report, the impacts of global warming are being felt worldwide including the South-West Indian Ocean where the frequency of extreme weather and climate events has been increasing since the last few decades. 

For this summer, it is likely that extreme weather events in the shape of heavy/torrential rain, violent thunderstorms, electric storms, mini tornadoes, rapid intensification of tropical cyclones may occur during the coming summer and cyclone season 2019-2020.  

High waves generated by tropical cyclones evolving in the vicinity of the Mascarene Islands may reach the shores of the islands and Mauritius. After careful analysis of the behaviour of all indicators and taking into consideration analogue patterns, it is concluded that the mean air temperature will be above normal during summer 2019-2020. “However, on certain days, temperature may exceed the monthly mean by more than three degrees Celsius in some locations. Maximum day temperatures may reach 360 Celsius at Port Louis and along the western coasts during peak summer months.”

Furthermore, above normal temperatures, coupled with prolonged periods of high humidity and light wind conditions, will result in torrid conditions, particularly during the months of January to March, causing severe discomfort. “The onset of summer rain will be in the second fortnight of December. Total summer rainfall is expected to be near normal with about 1,400 mm over Mauritius. During peak summer months, January to March 2020, atmospheric conditions will be conducive to the occurrence of extreme weather events such as heavy/torrential rain, heat wave and violent thunderstorms. Short duration of heavy rainfall will cause localised flash floods.”

Storm

The number of named storms evolving in the South-West Indian Ocean basin for the 2019-2020 summer season, i.e. from 1st November 2019 to 15th May 2020 is likely to be 8 to 10. “During this season, the region to the West of Diego Garcia is likely to be more conducive to storm formation. There is a probability of having the first named storm in the Southwest Indian Ocean basin by the end of November.”

Summer season of Mauritius is from 1st November to 30th April of the following year. However, the official cyclone season is from 1st November to 15th May. The start of the summer rain is defined as the first occasion after 1st November that the seven-day total is equal to or exceeds 50mm and includes at least four rainy days.