Cold Air Activity Expected in Southern Africa

Over the next three days, influenced by an upper-level cold vortex (Figure 1), moderate to heavy rain is expected in South Africa, southern Namibia, eastern and southern Botswana, and Lesotho, with localized heavy downpours. Rain mixed with snow will occur in high-altitude areas of Lesotho and South Africa's Eastern Cape Province. Accumulated precipitation will range from 30 to 60 mm, with localized amounts exceeding 80 mm (Figure 2). These areas will also see a temperature drop of 8–12℃, with the maximum local decrease surpassing 16℃. Additionally, winds of force 6–8 and gusts of force 9–10 will accompany the system (Figure 3). Attention should be paid to mitigating the adverse impacts of the precipitation, strong winds, and sharp temperature drops on road traffic, infrastructure, as well as agricultural and pastoral sectors.

Figure 1: Forecast of 500 hPa Geopotential Height (contours, units: dagpm) and Wind Field (barbs, units: m/s) at 12:00 UTC on September 4, 2026

Figure 2: Forecast of Accumulated Precipitation from 12:00 UTC on September 4 to 12:00 UTC on September 7, 2026 (Unit: mm)

Figure 3: 10-m Wind Speed Extreme Forecast Index (EFI) on September 5, 2026 (UTC)

https://www.wmc-bj.net

Author: Che Jinning                                Reviewer: Cai Xiangning 

English reviewer:Wang Yi                                                                    Issue approver:Dai Kan