A short-range multi-model ensemble weather prediction system for South Africa

Abstract

The objective of this paper is to present the temporal and spatial description of precipitation forecast skill over South Africa from an ensemble of multiple model runs. Numerical forecasts from an experimental short-range multi-model ensemble prediction system (EPS) at the South African Weather Service (SAWS) are examined. The ensemble consists of different forecasts from the 12-km LAM of the UK Met Office Unified Model (UM) and the Conformal-Cubic Atmospheric Model (CCAM) covering the South African domain. The multi-model ensemble consists of six members. The ensemble is simulated over a 0.5º grid for hourly precipitation for the austral summer season of October to March. The ensemble produces skill scores that are generally higher than those of the individual models, therefore providing the evidence that such a system can improve on deterministic rainfall forecasts that currently only uses the output of a single numerical weather model.