The summer 2017-2018 weather outlook by the Mauritius Meteorological Services (MMS) forecasts normal to slightly above normal temperatures for Mauritius, with temperatures exceeding the monthly average by more than two degrees Celsius on certain days in Port Louis and in some coastal areas during afternoons of peak summer months (January to March). Cumulative summer rainfall is expected to be near normal, with a mean of about 1350 mm.
The possible evolution of the 2017-2018 South West Indian Ocean (SWIO) summer, starting from 01 November 2017 to 15 May 2018, was presented by the Director of MMS, Mr Rajan Mungra, during a press conference on 31 October 2017 at the Mauritius Meteorological Services, Vacoas. The forecast covers specific climatic occurrences, namely cyclone activity, summer rainfall and temperature in Mauritius, Rodrigues, St Brandon and Agalega.
He underlined that according to regional and global observations over the past two decades, the frequency of extreme weather events has increased for the SWIO islands. It is very likely that extreme weather events in the form of heavy and/or torrential rainfall leading to flash floods, violent thunderstorms as well as electric storms, and heat wave with above normal temperatures lingering for days may occur during the forthcoming summer 2017-2018, he added.
A warmer summer 2017-2018 is expected as the maximum temperatures may reach 35 degrees Celsius in Port Louis and along the coastal areas on certain days. As regards Rodrigues, maximum temperatures are likely to reach 32 degrees Celsius along the coastal areas on certain occasions. Temperatures in St Brandon and Agalega, will be near normal with maximum reaching 31 and 32 degrees Celsius, respectively.
Successive days with above normal temperatures, high humidity and light wind may cause torrid conditions resulting in severe discomfort. Such conditions are more likely to occur from January to March 2018.
The onset of summer rainfall will be slightly delayed and is expected to occur during the second fortnight of December in both Mauritius and Rodrigues. The cumulative summer rainfall over Mauritius is expected to be near normal with about 1350 mm. However, the mean rainfall over Rodrigues will be slightly below normal with a mean of around 550 mm. In Agalega and St Brandon cumulative summer rainfall will be near normal with about 1200mm and 700 mm, respectively.
A total of six to eight storms are expected to evolve in the SWIO basin during the forthcoming summer. Most of the storms for this season are likely to form to the west of Diego Garcia and the first storm expected by the end of December 2017 is likely to be named Ava.
All named storms that will develop in the SWIO will not necessarily be a direct threat to the islands of the Republic of Mauritius. Nevertheless, the tropical cyclones may generate high waves and heavy swells that are most likely to reach the shores of the islands of the Republic of Mauritius.
Any storm/cyclone originating from the Australian region and entering the area of responsibility of Mauritius will retain its original name and vice versa.