Hội An Ancient Town's Cầu Pagoda in the central city of Đà Nẵng is submerged in water, exceeding the historic flood peak of 1964. VNA/VNS Photo Lê Lâm

HÀ NỘI — A surge of cold air combined with high-altitude easterly disturbances is expected to bring moderate to heavy rainfall, with some areas experiencing very heavy downpours and thunderstorms, across provinces from Nghệ An to Quảng Ngãi.

The National Centre for Hydro-Meteorological Forecasting warned that overnight and early Friday morning, heavy rain was recorded from Hà Tĩnh Province to northern part of Quảng Trị Province.

Rainfall measured between 7pm on Thursday and 3am Friday reached high levels, with some stations recording over 130mm, such as Hồ Thượng Sông Trí in Hà Tĩnh Province (266.6mm), Ba Đồn in Quảng Trị Province (346mm) and Khâm Đức in Đà Nẵng City (116.6mm).

From early Friday through to the end of Saturday, the localities from Nghệ An to northern part of Quảng Trị Province is forecast to experience heavy to very heavy rain, with totals ranging from 150 to 300mm, and isolated areas possibly exceeding 500mm.

Between Friday night and the end of Saturday, southern part of Quảng Trị Province to Quảng Ngãi Province are expected to receive 100-250mm of rain, with localised downpours exceeding 350mm.

Forecasters have issued warnings for intense rainfall, potentially exceeding 150mm within three hours.

On Friday, the region from southern part of Quảng Trị Province to Đà Nẵng City may also see moderate to heavy rain, with local rainfall of 15-30mm, and in some areas over 70mm within three hours.

Further rainfall is expected on Sunday, with widespread moderate to heavy rain from southern part of Nghệ An Province to Quảng Ngãi Province, averaging 70–150mm and locally exceeding 300mm.

The heavy rain over central provinces may persist until around next Tuesday.

Authorities warn of flooding in low-lying and urban areas, flash floods in small rivers and streams, and landslides on steep slopes. Thunderstorms may bring whirlwinds, lightning, hail and strong gusts.

Cold spell intensifies

The centre also said throughout Friday, the cold front will continue to strengthen, extending its impact over the northern and north-central regions before spreading westward and further south.

The northeast region is expected to see widespread rain due to the combined effects of cold air and easterly disturbances.

Northern and north-central regions will turn cold, with mountainous areas becoming chilly.

Minimum temperatures will generally range from 18-21 degrees Celsius, dropping below 17 degrees Celsius in mountainous regions.

Hà Nội will experience rain and cold weather, with lows of 19-21degrees Celsius.

Cold air and thunderstorms may damage crops, uproot trees, destroy houses and disrupt transport and infrastructure.

Prolonged heavy rain could lead to flooding in low-lying areas, flash floods, landslides and waterlogging in cities and industrial zones.

Strong winds and high waves will also pose risks to offshore fishing and marine transport, while colder weather may affect the health of the elderly and young children.

Floodwaters rising on Gianh river

The National Centre also reported that while water levels in rivers from Huế City to Đà Nẵng City are receding, the Gianh River in Quảng Trị Province is rising and is expected to peak just below Level 3 (the highest warning level).

In the next 12 hours, the Gianh River is forecast to continue rising to just below Level 3 before gradually receding to around 0.6m above Level 2.

Meanwhile, the Bồ and Thu Bồn rivers will continue to fall to about 0.2-0.3m above Level 2, the Hương River will drop to Level 2, and the Vu Gia River will fall to 0.3m below Level 2.

Within the next 12-24 hours, rivers across the region are expected to recede to between Level 1 and Level 2.

From Friday until next Wednesday, another flood wave is likely on rivers from provinces of Nghệ An to Quảng Trị.

During the period, upstream water levels on the Cả River (Nghệ An Province), Ngàn Sâu and Ngàn Phố rivers (Hà Tĩnh Province), Gianh, Kiến Giang and Thạch Hãn rivers (Quảng Trị Province) may rise to Level 2–3, with some exceeding Level 3. Downstream sections of the Cả and La rivers are expected to reach Level 1–2.

Flooding in Đà Nẵng City is gradually easing, while inundation in Huế City is expected to recede more quickly within the next one to two days.

However, there remains a high risk of flooding in low-lying and riverside areas, urban zones and residential clusters in provinces from Nghệ An to Quảng Trị.

Authorities also warn of a heightened risk of flash floods in small rivers and streams, as well as landslides on steep slopes, across provinces from Nghệ An to Đà Nẵng.— VNS