Sub-seasonal Monsoon Onset forecasting over West Africa

Skilful onset forecasts are highly sought after in West Africa, due to the importance of monsoon onset for agriculture, disease prevalence and energy provision. With research on the sub-seasonal timescale bridging the gap between weather and seasonal forecasts, sub-seasonal forecasts may provide useful information in the period preceding monsoon onset. This study explores sub-seasonal monsoon onset forecasts over West Africa using three operational ensemble prediction systems (ECMWF, UKMO, and NCEP) from the Sub-seasonal to Seasonal (S2S) prediction project database in order to determine the spatial scale and lead time at which sub-seasonal forecasts can provide useful monsoon onset information. Current research and operational methods of determining onset are identified and compared. The effect of spatial averaging on onset forecasting and skill is explored by comparing regional [Coast, Forest, Transition and North] and local forecasts at 4 major cities over Ghana.

 

‘This work was supported by UK Research and Innovation as part of the Global Challenges Research Fund, African SWIFT programme, grant number NE/P021077/1’