Ensemble flood forecasting in Africa: a feasibility study in the Juba-Shabelle river basin

The European flood alert system (EFAS) achieves early flood warnings for large to medium-size river basins with lead times of 10 days. This is based on probabilistic weather forecasts, the exceedance of alert thresholds and persistence. The methodologies have been tested for different events and time scales in mid-latitude basins in Europe. In this article, the transferability of the EFAS-methodologies to equatorial African basins is assessed with the analysis of the Juba-Shabelle river basin as an example using a variety of different meteorological data sources. In this context, ERA-40 and CHARM have been used for the calculation of climatologies; re-forecasts of the current operational European Centre for Medium-Range Weather Forecasts model provided hindcasts of historic flood events. The results show that flood events have been detected successfully in more than 85% of all cases, with a high accuracy in terms of timing and magnitude. Copyright (C) 2010 Royal Meteorological Society