As Gaborone Dam lies dry and the city continues to experience acute water shortages, news coming in from the Department of Meteorological Services (DMS) offer no glimmer of hope. Briefing stakeholders on the seasonal rainfall outlook for 2015/2016, Esther Janson of DMS said the south eastern parts of the country can expect the worst dry season since 1981.
“Our predictions show that the south eastern region will experience an extremely dry season, the worst since 1981,” she said. Janson said there is a strong El Ni├▒o presence. “There is a greater than 90 percent chance that El Ni├▒o will continue throughout the 2015/16 summer.”
She said this extremely dry season is expected throughout the south eastern region of Botswana, making it the worst in three decades. Janson said during the months of November, December and January 2015/16, Southeast, Kgatleng, Kweneng, Southern, North East, Central, and eastern parts of the CKGR are expected to receive below normal rains. “The northern and western parts (Ngamiland, Chobe, Gantsi, and Kgalagadi district) will receive normal to below normal rainfall.”
The same amount of rainfall is also expected in the same areas in the months of October, November and December. The southern parts of the country (Kgalagadi, Kweneng and Southeast) are also expected to receive normal to below normal rains in the same period. Ngamiland and Chobe are however expected to receive normal to above normal rainfall in the months of December, January, and February 2015/16.
The region is as a result expected to be moderately wet. The Southeast, Southern, Kweneng, Kgatleng extending into Gantsi and western Ngamiland are expected to continue to receive below normal to normal rainfall in the Months of January, February, and March 2016.
Overall, a deficit in rainfall is expected over the coming raining season mainly due to the potentially persistent El Ni├▒o conditions, says a statement from DMS. “The DMS has reviewed the state of the global climate systems and analysed the rainfall prospects for the period of October 2015 to March 2016,” the statement said. “Subsequently, the seasonal rainfall forecast for the upcoming rainfall season for Botswana was issued in an overlapping approach.” The DMS says the conclusions are based on the state of the Sea Surface Temperature (SSTs) over the Pacific, Indian, and Atlantic Oceans. It says the SSTs anomalies in east and central Pacific Ocean are depicting strong El Ni├▒o conditions which is likely to peak during the southern hemisphere summer. “It is expected that the well above SSTs in the Indian Ocean and the expected strong El Ni├▒o conditions will have a major influence on the weather and climate systems (patterns) over Botswana although they are not the only influencing factors for rainfall,” DMS. Other factors like the presence of tropical cyclones in the Indian Ocean, the DMS says, also contribute to the rainfall regime over the region.