Radar systems provide the most useful information about the intensity, movement, and characteristics of severe thunderstorms, but are expensive to maintain and require extensive maintenance. In South Africa, some areas are not covered by radar systems, while very few operational radar systems exist in other southern African countries. Despite these shortcomings, all meteorological centers still have to warn the public of pending severe weather events. The Nowcasting Satellite Application Facility (NWC SAF) in Europe developed software that utilizes satellite data to identify and track rapidly developing thunderstorms (RDT). The NWC software was installed at the South African Weather Service in 2014. Initially, the RDT product was validated against lightning data and the results showed that the RDT product could provide very useful information on possible severe or intense convective storms. This study focusses on the effects of including lightning as an ancillary dataset into the algorithms and then validating the RDT product against radar data. Twenty-five summer cases were considered to determine whether the inclusion of lightning data had a positive effect on the accuracy of the RDT product, when compared to radar data. The results of this study show that in the majority of the cases, the inclusion of lightning data was beneficial to the RDT product. On average the Probability of Detection (POD) improved by 6.6%, the Heidke Skill Score (HSS) by 4.6%, and the False alarm ratio (FAR) by 0.1%. To our knowledge, South Africa is the only African country which is running the NWC SAF software operationally and which has performed an evaluation of the product over Africa against observations from radar systems and lightning sensors. The outcomes of this study are very encouraging for other countries in Africa where convection and severe convection often occur and sophisticated data sources are absent. Initial studies over East Africa indicate that the RDT product can benefit operational practices for the nowcasting of severe convection events.

Nowcasting has enormous value and potential in Africa, where populations and economic activity are highly vulnerable to rapidly changing weather conditions, including rapidly developing storms, heavy rainfall and dust storms, which are becoming more frequent and intense with climate change. Timely issuing of warnings, a few hours before an event, can enable the public and decision makers to take action, which can save lives and livelihoods, as well as support national economies. The potential applications of nowcasting across the continent are wide-ranging, and can cover various sectors and activities, including urban warning systems for flash floods, early warnings to fisherfolk at risk from drowning on lakes, protection of crops, water management systems, protection of cattle, aviation warnings as well as the transport sector. The vulnerability of African countries to weather-related risks make the continent a priority for the development of nowcasting, and is the primary driver for recently published "Guidelines for Satellite-based Nowcasting in Africa". It provides guidelines for the implementation of a range of satellite nowcasting capabilities available for Africa with the advent of the Meteosat Third Generation (MTG) satellite system. The successful launch of the first MTG satellite on 13 December 2022 marks a major improvement over the previous geostationary satellite system. This aligns very well with the UN SG announcement to improve Early Warnings for All, led by the WMO and UNDRR. The present guidelines are urgently needed, given that there is currently a lack of early warnings on this timescale in Africa. The guidelines aim to provide recommendations that will help facilitate near-term implementation, as well as the development of capacity and sustainability of services overtime. The various options are broken down in the document into different technical, operational, logistical and management aspects. The guidelines can be used to create templates and roadmaps for the establishment and maintenance of nowcasting functions in African countries. The intended readership includes National Meteorological and Hydrological Services in Africa, Regional Specialized Meteorological Centres, Regional Training Centres, WMO-CGMS VLab Centres of Excellence for Training in Satellite Meteorology, and international agencies.