WINDHOEK – The 2014/15 rainy season which started in October in Namibia would be normal to wetter than normal, an independent South African forecaster said.
Speaking at last week’s Agricultural Outlook Forum in Windhoek, Professor Hannes Rautenbach of the University of Pretoria focused on the different models and the results of climate change in Southern Africa.
He pointed out a prediction of Cobus Olivier of the SA Weather Office which does not bode well for Namibia. It seems from this prediction that there is a bigger possibility of an under-normal rainy year.
From three conferences the past two months, it was difficult to get unity regarding the expectations for rain in the current season. In September the Southern African Regional Climate Outlook Forum predicted an average to an above-average rainy season whilst the Agricultural Outlook Conference in South Africa was more pessimistic for the first part of the rainy season, but with expectations of an average year as from January 2015.
According to the SADC outlook for October 2014 to March 2015, Southern African Development Community (SADC) countries are likely to receive normal to above-normal rainfall for the period October to December 2014, but the rains have stayed away in the first part of October.
In the November-December 2014 – January 2015 period, the bulk of the SADC region is likely to receive normal to above-normal rainfall, while the greater part of DRC and northernmost Angola are likely to receive normal to below-normal rainfall.
For the period January to March 2015, the bulk of SADC is expected to receive normal to above-normal rainfall. However, the greater part of the DRC, northernmost Angola and Mauritius are likely to receive normal to below-normal rainfall.
The rainy season is divided into overlapping three-month periods for the purposes of the forecast, and regional meteorologists foresee that most of Namibia – with the exception of the area along the country’s coast – will have a 35 percent probability of above-normal rainfall, a 40% chance of normal rainfall, and a 25% chance of below-normal rainfall over the three months from October to December.
Prof. Rautenbach does not necessarily agree with this forecast and pointed out the vital role of global warming in the years to come.
From November to January and also from December to February, the forecast by various other experts is that all of Namibia will have a 35% probability of above-normal rainfall, a 40% chance of normal rainfall, and a 25% chance of below-normal rainfall.
From January to March, it is expected that the areas along the coastline and roughly the western half of the //Karas Region will have a 40% chance of above-normal rainfall, 35% probability of normal rainfall, and a 25% chance of below-normal rainfall.
Over the rest of the country, the forecast is also a 35% probability of above-normal rainfall, a 40% chance of normal rainfall, and a 25% chance of below-normal rainfall from January to March.
Ocean surface temperatures were one of the factors taken into account by all the climate scientists who compiled the seasonal forecast, SADC Climate Services Centre coordinator Bradwell Garanganga said. According to him, the ocean surface temperatures in the central and eastern equatorial Pacific Ocean are near neutral at the moment, after these temperatures had appeared to be rising a few months ago.
If the ocean surface temperatures in that part of the Pacific Ocean rise above normal levels, an El Niño event occurs, with global weather patterns affected as a result.
In Southern Africa, El Niño usually signifies drought or a below-normal rainy season.