The Southern Regional Hydrometeorological Center said the area is under the influence of a low-pressure trough linked to a western heat low, which has been compressed and shifted southward. 

At higher altitudes, a subtropical high-pressure system is moving north, combined with upper-level wind disturbances that are triggering thunderstorms.

Satellite and radar data showed storm clouds developing and producing rain, lightning, and thunderstorms in multiple areas, including Binh Tien, Tan My, Tan Hung, Phu Dinh, Dien Hong, Phu My, Binh Loi, Bac Tan Uyen, Phu Giao, Ngai Giao, Kim Long, Bau Lam, Hoa Hiep, and Thanh An.

The agency forecast that convective cloud systems would continue to develop in the coming hours, bringing showers and thunderstorms that could spread to nearby areas. 

Rainfall is expected to range between 5 mm and 20 mm, with some locations receiving more than 50 mm.

Authorities warned of possible whirlwinds, lightning, hail, and strong winds of up to seven on the Beaufort scale during storms. 

Heavy rain may also cause localized flooding in low-lying areas.

Localized downpours could raise the risk of flash floods on small rivers and streams, as well as landslides on steep slopes, the agency said.

Despite the rainfall in the late afternoon and evening, daytime conditions remain hot and humid, typical of the seasonal transition period in southern Vietnam.