Scattered showers and thunderstorms affected northwestern Vietnam, the central region and southern Vietnam on July 26, with some areas experiencing heavy rain, according to the National Centre for Hydro-Meteorological Forecasting.
On the evening and night of July 26, scattered showers and thunderstorms are forecast across the Northwest, from Hue City to Daklak and Khanh Hoa Province, with rainfall of 10-30mm and isolated totals exceeding 60mm.
The southern region and Lam Dong Province are expected to see rain, moderate rain and thunderstorms, with rainfall of 20-40mm and isolated areas receiving more than 100mm.
From the evening of July 27 through July 28, Thai Nguyen Province, Tuyen Quang Province, Phu Tho Province, Lao Cai Province, Lai Chau Province, Dien Bien Province and Son La Province are forecast to experience moderate to heavy rain and thunderstorms. Rainfall is expected to range between 30mm and 70mm, with isolated locations receiving more than 150mm.
Elsewhere across northern region, rainfall of 20-40mm is forecast during the same period, with isolated areas likely to record more than 70mm.
Forecasters also warned of intense downpours capable of producing more than 100mm of rain within three hours.
On the night of July 28, the seven provinces are expected to continue experiencing moderate to heavy rain and thunderstorms, with rainfall of 20-50mm and isolated areas exceeding 100mm.
Total rainfall from the evening of July 27 through the night of July 28 is forecast at 50-120mm across Thai Nguyen, Tuyen Quang, Phu Tho, Lao Cai, Lai Chau, Dien Bien and Son La provinces, with isolated locations likely to receive more than 250mm.
The Central Highlands and southern region are also forecast to receive rain and moderate rainfall of 20-50mm, while isolated areas could see more than 100mm.
The weather agency warned that thunderstorms may be accompanied by tornadoes, lightning, hail and strong wind gusts.
Heavy and locally intense rainfall could trigger flooding in low-lying areas, urban and industrial zones, as well as flash floods along small rivers and streams and landslides on steep slopes.