According to the National Centre for Hydro-Meteorological Forecasting (NCHMF), widespread heavy rain continued across Northern Vietnam overnight on May 18 and into the early hours of May 19. Viet Lam Station in Tuyen Quang province recorded rainfall of up to 305.6mm, while Bach Thong in Thai Nguyen province reached 116mm. In Quang Ninh province, Dam Ha recorded 144.4mm of rainfall.

The prolonged downpours have sharply increased the risks of flashfloods, landslides, and ground subsidence in many mountainous localities, particularly in Tuyen Quang, Cao Bang, and Quang Ninh.

Forecasts indicate that Northern Vietnam and the North-central region from Thanh Hoa to Nghe An will continue to experience moderate to heavy rain and thunderstorms throughout May 19, with common rainfall levels ranging between 40mm and 80mm and some locations expected to exceed 180mm. Scattered showers and thunderstorms are also expected to persist across the northern mountainous and northeastern regions.

The unstable weather pattern has also spread beyond Northern Vietnam. Areas stretching from Ha Tinh to Lam Dong, along with Southern Vietnam, are expected to continue experiencing widespread thunderstorms, mainly during the evening and nighttime hours. Some localities have already recorded substantial rainfall totals, including 96mm in Ngok Reo of Quang Ngai and 77.2mm in Hoai An of Gia Lai.

Meteorological authorities warned that localised rainfall intensity could exceed 100mm within a short period, potentially causing urban flooding, flashfloods in mountainous areas, and landslides along steep slopes. The current heavy rain event affecting Northern and North-central Vietnam is expected to continue through May 21.

According to weather experts, this type of widespread heavy rainfall is relatively unusual for mid-May. The phenomenon is linked to a monsoon trough shifting farther south toward Northern Vietnam instead of remaining over Southern China, which is considered the more typical seasonal pattern.

When interacting with a western low-pressure hot zone, the system generated strong convective weather conditions, resulting in widespread thunderstorms and localised extreme rainfall. Rainfall totals reaching between 200mm and 300mm during mid-May are considered highly unusual.

Despite entering the early summer period, Northern Vietnam this year has continued to experience the influence of weak late-season cold air masses. While these systems do not cause severe cold conditions, their interaction with high temperatures and humidity during the seasonal transition has intensified thunderstorms and, in some localities, even produced hail.

Forecasters expect rainfall intensity to gradually decrease after May 21. However, weather conditions are likely to remain unstable during the ongoing seasonal transition, and residents are advised to stay alert for thunderstorms, lightning, strong winds, and other extreme weather events.

Weak cold air brings rain, Northern Vietnam cools after heatwave

VOV.VN - After several days of intense heat, weather conditions across many parts of Vietnam, especially in the north, shifted noticeably as widespread showers and thunderstorms arrived from the evening of May 16.