SADC rainy season forecast to extend to May
THE 2017/18 rainfall season in southern Africa is likely to continue until May, according to regional weather experts. This is a change from previous seasons where the rainfall ended around March/April. According to the 21st Southern Africa Regional Climate Outlook Forum (SARCOF-21) Mid-season Review and Update released in December 2017, most parts of southern Africa are expected to receive an increased amount of rainfall in the period January to May 2018.
Chances of increased rainfall in the region will be a welcome development, particularly in the southern parts of the region where low rainfall resulted in delays in planting and crop moisture stress in some areas.
In areas such as southern Mozambique, southern Zambia and Zimbabwe, crops are already showing signs of moisture stress due to the prevailing dry spells.
Reports from Namibia indicate that low rainfall has resulted in deterioration of grazing pasture for livestock in several areas across the country.
Farmers, especially in these affected areas in the Southern African Development Community (SADC) are beginning to worry about the effect of the current erratic rains on crop production.
According to the SARCOF-21 Mid-season Review and Update, almost the whole of southern Africa has increased chances of receiving high rainfall characterised as “normal to above-normal” during the period January to March, with the exception of a few areas. Areas with a likelihood of receiving less rainfall termed as “normal to below-normal” are the south-westernmost parts of Angola and the western fringes of both Namibia and South Africa.
The review indicates that only north-western Democratic Republic of Congo and the easternmost parts of Madagascar are expected to have increased chances of normal to below-normal rainfall during the period March to May 2018.
According to the mid-season update and review, above normal rains were received in most areas of the northern part and north-eastern part of the region whereas the central and south-western parts of the region such as Botswana and Zimbabwe received less rainfall during the October-November 2017 period.
The update shows that the Inter-Tropical Convergence Zone (ITCZ), which is the main rain-bearing mechanism for southern Africa, is still very active and is centred over the northern and eastern parts of the region. Based on the forecast by weather experts in the mid-season update, there is a possibility that farmers who planted late may harvest good yields considering that rainfall is likely to end in May.
The update is, however, only relevant to seasonal time scales as well as relatively large areas and may not fully account for all local and intra-seasonal factors that influence weather patterns.
It is, therefore, crucial that farmers and other users of climate information contact their national meteorological and hydrological offices for better interpretation and regular updates. While increased moisture is expected to improve crop productivity, flooding could destroy crops and impact on food security.
Excessive rainfall may increase the incidence of malaria and waterborne diseases in the region and the possibility of damage to infrastructure due to flooding.
One of the challenges still affecting SADC member states is the lack of current and reliable data on possible weather scenarios. To reduce vulnerability to floods, countries in the region will need to improve on data and information-sharing and ensure that affected communities are evacuated on time when weather-related natural disasters occur.
There is also need to retrofit public infrastructure such as schools as they act as both centres of learning and as sanctuaries in cases of emergencies such as floods. River Basin Organisations (RBOs) are making efforts to improve the sharing of information on water flow and climate conditions.
One such RBO is the Zambezi Watercourse Commission, which is in the process of strengthening data and information sharing in the eight basin states through implementing the Zambezi Water Resources Information System Enhancement 3: Hydro-meteorological Database and Decision Support System (ZAMWIS-DSS).— sardc.net
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