Weather forecast for southern Africa predicts good rainfall this season

by Admire Ndhlovu – SANF 16 no 45
The forecast for the 2016/17 cropping season in southern Africa indicates that most parts of the region can expect adequate rainfall after two successive years of debilitating droughts.

In the period October to December most of the region is expected to receive a high amount of rain, characterised as “normal to above normal” rainfall, and this is expected to continue in most parts of the region in January to March 2017, according to a statement by the 20th Southern Africa Regional Climate Outlook Forum (SARCOF-20).

However, the northern part of the region can expect “normal to below normal” rainfall at the beginning and end of this period, comprising northernmost Democratic Republic of Congo (DRC), northern Angola, most of Tanzania, northern Mozambique, the island states of Seychelles and eastern Madagascar.

The period November to January may see a reduction in rainfall in some parts of the region, including western Botswana, eastern DRC, northern Mozambique, western Zambia, and southern Tanzania. It is during this period that the region often experiences a dry spell, but the coming season is expected to be characterised by a short dry spell this season in most parts of the region.

The predicted rainfall patterns are presented with maps that show the entire SADC region receiving normal to above normal rainfall during the period December 2016 to February 2017, with the except of eastern Tanzania and eastern Madagascar.

During the period of January to March 2017, the rainfall will decrease in the northern part of the region, as well as the southern parts of Zimbabwe and Mozambique, eastern Botswana, northern and central South Africa.

The forecast was formulated by climate scientists from the National Meteorological and/or Hydrological Services in the 15 Member States of the Southern African Development Community (SADC) and the SADC Climate Services Centre, with additional inputs from other global climate prediction centres.

Their statement notes that the Outlook is relevant only to seasonal timescales and relatively large areas and may not fully account for all local and intra-seasonal factors that influence climate variability, which can be interpreted and updated by national meteorological and hydrological services.

SARCOF meets every year in August to review the rainfall season in SADC, and discuss the potential impacts of the consensus seasonal climate outlook on other socio-economic sectors including disaster risk management, food security, health, water resources and hydropower management.

The statement from climate scientists said they “took into account oceanic and atmospheric factors that influence our climate over the SADC region. In particular, the El Niño-Southern Oscillation (ENSO) is foreseen to be shifting from the warm, through neutral to cold phase, also referred to as La Niña, during the bulk of the rainfall season.”

Many regions of the global tropics and sub-tropics exhibit climate anomalies that correlate with the El Niño Southern Oscillation, a naturally occurring phenomenon that involves fluctuating ocean temperatures in the equatorial Pacific.

In southern Africa, an El Niño event is characterised by drought while La Niña is associated with wet conditions and floods.

While increased soil moisture is expected to improve crop productivity, there is a risk of flooding that could destroy crops and impact on food security. Damage to infrastructure is possible. Increased incidences of malaria and waterborne diseases are often associated with higher rainfall.

Mozambique, for example, faces risks of cyclone landfalls due to increased tropical cyclones forming in the Mozambique Channel, with a possibility of displacement of people.

Governments in the region are taking proactive measures to prepare for the change in the rainfall patterns and its impact on livelihoods and economic sectors.

River Basin Organisations such as the Zambezi Watercourse Commission, Limpopo Watercourse Commission and Orange-Senqu River Commission are strengthening data and information sharing, which is crucial for early warning and preparedness, particularly in the case of floods. The commissions have already set up data and information-sharing systems.

At regional level, the SADC Climate Services Centre is establishing a Climate Data Processing Centre to provide timely early warning information such as flood and drought potential prediction, onset of rainy season, as well as climate advisories and information.

These are critical in development of effective drought and flood warning systems to maximize the opportunity for the implementation of response strategies aimed at enhancing the safety of life and property and reducing avoidable flood damage.

Climate events such as El Nino and La Niña are a slowly evolving phenomenon, whose peak can be predicted months in advance. Providing early advice and warning can help to reduce vulnerability to the impacts.

The 20th SARCOF meeting held on 24-26 August was hosted by the Meteorological Services of Zimbabwe. sardc.net


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