According to the National Center for Hydro-Meteorological Forecasting, a strong cold front had reached northwestern Vietnam, the north-central region and parts of the central region by the afternoon of November 9.

Northern Vietnam experienced showers and thunderstorms, with heavy rainfall in some areas. Moderate to heavy rain and thunderstorms also affected the region from Thanh Hoa to Hue, with exceptionally heavy rainfall in some locations.

At 1pm, temperatures generally ranged from 18-21°C, dropping to 15-18°C in mountainous areas.

Strong northeasterly winds were recorded in several coastal and island areas. Bach Long Vi Island reported force 8 winds, gusting to force 10 on the Beaufort scale, while Co To Island experienced force 6 winds with gusts reaching force 8-9. Ly Son Island also recorded force 6 northeasterly winds.

Cold front expands southward, Hanoi temperatures fall to 16°C

The cold air mass was forecast to continue moving southward during the evening and night of November 9, affecting the remaining parts of the central region and some areas farther south.

On land, northeasterly winds were expected to reach force 3-4, increasing to force 5 along coastal areas, with some locations experiencing force 6 winds and gusts of force 7.

The cold front was forecast to bring chilly conditions across northern Vietnam and the region from Thanh Hoa to Quang Tri. Hue was also expected to turn cooler from the night of November 9.

Minimum temperatures during the cold spell were forecast to range from 15-18°C across northern Vietnam and the Thanh Hoa-Quang Tri region, with some high-altitude areas in the north dropping below 12°C.

In Hanoi, scattered rain and colder weather were expected.

By the evening of November 9, temperatures in many parts of the capital had fallen by more than 10°C compared with the previous day, accompanied by relatively strong northeasterly winds.

The city's overnight minimum temperatures were forecast to fall to 16-18°C, making conditions feel noticeably colder.

Central Vietnam braces for rainfall exceeding 500mm

The combination of the cold front and disturbances in upper-level easterly winds was forecast to bring widespread heavy rainfall to central Vietnam.

On November 9, moderate to heavy rain and thunderstorms affected areas from Thanh Hoa to Hue, with exceptionally heavy downpours in some locations.

Between 7am and 3pm, several weather stations recorded rainfall exceeding 100mm. Ky Lac in Ha Tinh registered 222.2mm, while Dong Tam in Quang Tri recorded 151.6mm.

From the evening of November 9 through the morning of November 10, Ha Tinh and northern Quang Tri were expected to experience heavy to extremely heavy rain and thunderstorms, with accumulated rainfall of 60-120mm and more than 200mm in some areas.

From the evening of November 9 through November 11, Hue, Da Nang and eastern areas of provinces from Quang Ngai to Gia Lai were forecast to receive 150-300mm of rain, with some locations exceeding 500mm.

During the same period, southern Quang Tri, eastern Dak Lak and Khanh Hoa were expected to receive 100-200mm, with isolated areas recording more than 300mm.

Meteorologists warned that intense downpours could exceed 100mm within just three hours.

Residents were also advised to remain alert for tornadoes, lightning, hail and strong wind gusts during thunderstorms.

By the night of November 11, Hue, Da Nang and eastern areas from Quang Ngai to Dak Lak were expected to continue experiencing heavy rainfall of 30-60mm, with some locations receiving more than 100mm.

Heavy rainfall across central Vietnam was forecast to gradually ease from November 12.

The national weather agency warned that prolonged downpours could trigger flash floods in small rivers and streams, landslides on steep slopes and flooding in low-lying areas.

Rough seas forecast, with waves reaching 6 meters

Strong northeasterly winds were also expected to continue affecting several maritime areas during the night of November 9 and throughout November 10.

In the Gulf of Tonkin, northeasterly winds were forecast at force 6-7, occasionally reaching force 8 overnight, with gusts of force 9-10. Waves were expected to reach 4-6 meters, creating very rough seas.

The northern East Sea, including the Hoang Sa (Paracel) Islands, was forecast to experience force 7 northeasterly winds, occasionally reaching force 8, with gusts of force 9-10 and waves of 4-6 meters.

In the northern part of the central East Sea and waters stretching from southern Quang Tri to Quang Ngai, winds were expected to strengthen to force 6, occasionally reaching force 7, with gusts of force 8-9 and waves of 3-5 meters.

Meanwhile, the southern part of the central East Sea, waters from Gia Lai to Ca Mau and the western part of the southern East Sea, including waters west of the Truong Sa (Spratly) Islands, were forecast to experience force 5 northeasterly winds, occasionally reaching force 6, with gusts of force 7-8.

Wave heights in these areas were expected to range from 2-4 meters, resulting in rough sea conditions.

Bao Anh