According to the National Center for Hydro-Meteorological Forecasting, a cold air mass is currently moving south from the north. The meteorological agency has forecast the cold air mass in the next 24 to 48 hours.
Before the cold air covers, the North and Thanh Hoa have showers and thunderstorms.
From the evening and night of September 29 to the night of September 30, the Northern region and Thanh Hoa will have moderate rain, heavy rain, locally very heavy rain and thunderstorms with common rainfall of 40 - 120mm, locally over 200mm.
Thunderstorms may produce tornadoes, lightning, hail and strong winds.
Thunderstorms accompanied by tornadoes, lightning, hail and strong winds can affect agricultural production, cause trees to fall, damage houses, traffic works and infrastructure.
Heavy rains can cause flooding in low-lying areas; flash floods in small rivers and streams, and landslides on steep slopes.
Around October 1, the cold air mass will affect the Northeast region, then affect most of the Northwest region, North Central region and some places in Central Central region. The wind will change to northeast inland level 3, coastal areas level 4 - 5.
Day and night on October 1, the North has the lowest temperature of about 20 - 23 degrees Celsius, in mountainous areas some places below 20 degrees Celsius. The average temperature during the day is about 24 - 26 degrees Celsius, in mountainous areas some places below 24 degrees Celsius.
During this cold spell, the weather in the North and North Central regions will turn cool. The nights and early mornings will be cold, especially in the mountainous areas of the North.
The lowest temperature in the North and Thanh Hoa is commonly from 19 - 22 degrees Celsius, in mountainous areas 17 - 19 degrees Celsius, in high mountainous areas in some places below 16 degrees Celsius.
In Nghe An - Ha Tinh area, the lowest temperature is commonly from 20 - 23 degrees Celsius.
At sea, from noon on October 1, in the Gulf of Tonkin, the northeast wind will gradually increase to level 6, gusting to level 7-8; rough seas; waves 1.5-2.5m high.
Strong winds and large waves at sea are likely to affect boating and other activities.
