Heavy Rainfall Will Occur in Southern West Africa

Over the next four days（from July 31 to August 3）, influenced by a low-level vortex (Figure 1), southern West Africa will experience moderate to heavy rainfall from east to west. In particular, parts of northern Nigeria, southern Niger, northern Benin, Burkina Faso, southern Mali, and southern Mauritania will see torrential rain, with localized areas experiencing extremely heavy downpours. These conditions will be accompanied by severe convective weather, including short-duration intense rainfall and thunderstorms with strong winds. The cumulative rainfall in these regions is generally expected to be between 20 and 40 mm, with some areas receiving 50 to 120 mm, and locally exceeding 200 mm (Figure 2). Attention should be given to the potential for localized heavy rainfall to trigger secondary disasters such as flooding in small and medium-sized rivers and urban waterlogging.

Figure 1  500 hPa Geopotential Height (Contour Lines) and 850 hPa Wind Field (Wind Barbs) at 1200 UTC, August 2, 2025

Figure 2  Forecasted Accumulated Rainfall from July 31 to August 3, 2025 (Unit: mm)

Author: Xie Jin                                                              Reviewer: Cai Xiangning 

English reviewer:Wang Yi                                                                       Issue approver:Dai Kan