A cold front will affect Northern Vietnam tomorrow.

On land, around late afternoon and night of October 4th, this cold air mass will affect the Northeast region, then other areas in the North and the area from Thanh Hoa to Hue city. On land, winds will shift to northeasterly at level 2-3, and level 3-4 in coastal areas.

In the Northeast region and Thanh Hoa province, the weather will turn cold from the night of October 4th, with some mountainous areas experiencing freezing temperatures. The lowest temperatures during this cold spell in the Northern region and Thanh Hoa will generally range from 19-22 degrees Celsius, and 14-17 degrees Celsius in mountainous areas.

From early morning on October 5th, a cold front affected the Hanoi area. From the night of October 4th to the morning of October 5th, there was rain, moderate rain and thunderstorms, with heavy rain in some areas; from early morning on October 5th, the weather turned cold.

At sea, from around dawn and morning of October 5th, in the Gulf of Tonkin, the wind will shift to the northeast and strengthen to level 6, sometimes level 7, with gusts of level 8-9; sea waves will be 2-3m high; the sea will be rough. From October 5th, the northern part of the South China Sea will experience strong northeast winds of level 6-7, with gusts of level 8-9; sea waves will be 2-4m high; the sea will be rough. From October 6th, the strong wind area will expand to the northern South China Sea (including the Hoang Sa Special Economic Zone).

From October 4th to the morning of October 5th, Northern Vietnam will experience rain, moderate rain, and thunderstorms, with some areas experiencing heavy to very heavy rain. From the night of October 4th to October 6th, the area from Thanh Hoa to Hue City will have moderate rain and thunderstorms, with some areas experiencing heavy to very heavy rain. During thunderstorms, there is a high possibility of tornadoes, lightning, hail, and strong gusts of wind.

Thunderstorms accompanied by tornadoes, lightning, hail, and strong gusts of wind affect agricultural production, causing trees to fall, damaging houses, transportation infrastructure, and other facilities. Localized heavy rainfall can cause flash floods on small rivers and streams, landslides on slopes, and flooding in low-lying areas.