WISER-EWSA Extended Testbed
WISER-EWSA Project Extended Testbed in Southern Africa
Extreme weather in southern Africa causes significant damage and puts many lives at risk each year. The Weather and Climate Information Services (WISER) programme is an international initiative aimed at transforming access to weather information to inform decision-making at local, regional and national levels. WISER’s Early Warnings for Southern Africa (EWSA) project focuses on providing impact-based short-term weather forecasts using nowcasting. Nowcasting involves using real-time observations to provide predictions for up to six hours ahead. The EWSA project brings together an international team of meteorologists, academics, economists and user engagement specialists from the United Kingdom, South Africa, Mozambique and Zambia.
Following the success of the first intensive testbed, which ran for 2 weeks at the end of January 2024, an extended testbed was launched to cover the entirety of the rainy season in Southern Africa, from October 2024 to April 2025. During this period, experienced forecasters monitor extreme weather and its potential impacts to decide whether an intensive nowcasting event (INE) will be declared.
Each day begins with a briefing meeting where forecasters from each country review the synoptic forecast and discuss the likelihood of an INE in the upcoming days. Nowcasting all weather at all times isn’t feasible, so this meeting allows forecasters to focus their energy and resources on high-impact events.
When an INE is declared, a dedicated forecaster begins nowcasting using tools such as NWCSAF’s convective rainfall rate and rapidly developing thunderstorms products. The forecaster sends six-hour outlooks and two-hour warnings through various channels including text messages, radio alerts and the FASTA app. This continues until the event subsides so users are kept aware of the intensity of the event and the impacts as it develops.
An important part of the EWSA project is to ensure everyone receives warnings and understands what actions to take to reduce risk, particularly people with disabilities. Feedback is collected from users in three community hubs: Boane in Mozambique, Katlehong in South Africa and Kanyama in Zambia. This feedback includes the severity and the impacts of the weather event which are discussed in a post-INE review meeting alongside evaluations using rain gauge data and various nowcasting tools.
The extended testbed has provided a valuable opportunity to integrate nowcasting into daily operations. The daily commitment made by forecasters ensures nowcasting resources are focused on high-impact weather events, delivering timely, action-based forecasts to those who need them.
Author: Kasia Nowakowska