Latest cold air news: Weak cold air is about to come, ending the series of scorching hot days occurring in all three regions.
After the April 30 - May 1 holiday, the North welcomed a weak cold air mass moving down from mainland China, the weather turned to thunderstorms after the heat wave.
According to the National Center for Hydro-Meteorological Forecasting, on April 29 and 30, the Northwest region and the area from Thanh Hoa to Phu Yen will have especially severe heat with the highest temperature commonly ranging from 39-42 degrees Celsius, in some places over 42 degrees Celsius. The lowest relative humidity commonly ranges from 30-35%.
Latest cold air news: Cold air flows in to end the hot weather, warning of thunderstorms and tornadoes lasting for many days in the North
Other areas in the North, Central Highlands and South have hot and extremely hot weather, some places are especially hot with the highest temperature commonly ranging from 35-39 degrees Celsius, some places above 39 degrees Celsius. The lowest relative humidity commonly ranges from 40-50%.
The area from Khanh Hoa to Binh Thuan has hot weather with the highest temperature commonly ranging from 35-36 degrees Celsius, some places above 36 degrees Celsius. The lowest relative humidity commonly ranges from 50-55%.
The National Center for Hydro-Meteorological Forecasting predicts that the heat wave will gradually decrease from May 1-2 in the North and Central regions; from May 4-5 in the Central Highlands and the South. The risk of natural disasters due to heat wave is level 1; in particular, the areas of Son La, Hoa Binh and from Thanh Hoa to Phu Yen are level 2.
From the evening and night of April 30 to May 1, due to the influence of weak cold air combined with high-altitude wind convergence, Hanoi's weather is likely to have scattered showers and thunderstorms, and the heat will decrease. On May 1, the highest temperature will drop by 8 degrees compared to before, and the weather will be cool.
Mr. Nguyen Van Huong, Head of Weather Forecasting Department, National Center for Hydro-Meteorological Forecasting said: Currently, we are in the transitional season, there is often conflict between air masses with different characteristics, the atmosphere becomes more unstable, so thunderstorms also occur more often than at other times of the year.
In some cases where convection thunderstorms develop strongly, in addition to causing heavy rain, they may also be accompanied by hail and strong gusts of wind.
The thunderstorm on April 24 in the area between Hoa Binh and Son La is a typical example, caused by the influence of the southern edge of a weak cold air mass, combined with the activity of a wind convergence zone at an altitude of 1,500m created by the western edge of the subtropical high pressure tongue (a maritime air mass encroaching from the east), plus the southwest wind moving from Upper Laos, converging in the area along the 105th meridian.
In early May, the North and South need to be on guard against thunderstorms, tornadoes, lightning, hail and strong winds.
Mr. Huong said that according to satellite data, the estimated temperature of the convective cloud top during the storm was -81.2 degrees Celsius. This is a sign that the convective cloud tower is developing very violently.
The height of the cloud mass can be over 10km. The outbreak of such cloud towers often appears during the changing seasons and causes strong thunderstorms or hail.
"We forecast that after April 30, around May 1-3, there is a possibility of an interaction similar to the weather pattern on April 24, that is, high temperatures with a little cold air causing thunderstorms in the Northern region, in which the focus of the region and the mountainous region of the Northern Midlands and Mountains around the night of April 30 and May 1 is likely to experience thunderstorms and strong gusts of wind," said Mr. Huong.
Cold air returns in the first day of May, thunderstorms return to the North
Mr. Nguyen Van Huong said that depending on each region, the time when thunderstorms occur is different in each locality. However, in general, in our country, thunderstorms usually start from the end of March and end around the end of November, early December. Tornadoes usually occur from April to October.
In the North and North Central regions, this phenomenon is almost absent in the winter. Tornadoes often occur in the summer, especially in mountainous and coastal areas. In the South, the phenomenon of tornadoes in the summer is not as common as in the North and Central regions.
According to experts, it is very difficult to recognize and predict when hail will occur. Therefore, proactive prevention is still the main solution to minimize damage caused by hail.
To proactively respond to hail, when hail occurs, people should find safe shelters, concentrating in houses with flat roofs or solid corrugated iron roofs. If you are in a house with Fibrocement roof, you should find a place where you can "hide" such as under the table, under the bed, find hard objects to cover your head to prevent falling stones from breaking the tiles.
In the long term, to prevent hail from occurring, when building a house, people should pay attention to the structure of the roof frame and purlins, which must use good load-bearing, corrosion-resistant materials and be carefully reinforced. When building a roof, it should be designed with a slope on both sides. This way of building a roof will reduce the impact force from hail, helping to reduce damage caused by hail.
According to experts, it is difficult to predict thunderstorms, lightning, and hail in the future, and we can only focus on early warnings. Therefore, the National Center for Hydro-Meteorological Forecasting recommends that during the transitional season, people should regularly update weather forecasts; especially warnings related to thunderstorms, lightning, and hail.
At the same time, when there are early warnings, people should avoid leaving their homes during thunderstorms and find safe shelter.
According to the representative of the meteorological agency, this phenomenon of thunderstorms and hail is still likely to occur in the Northern, Central and Southern provinces in the coming time because from now until early June is the transitional season. "This phenomenon of thunderstorms and hail this year may occur more frequently and more intensely because the temperature is higher than the average of many years" - Mr. Huong warned.
In early May, the North and South need to be on guard against thunderstorms, tornadoes, lightning, hail and strong winds.
The meteorological center warns that currently in the transitional season, there is often a conflict between air masses with different characteristics, the atmosphere becomes more unstable, so thunderstorms occur more often than at other times of the year. In some cases, thunderstorms with strong convection develop, in addition to causing heavy rain, there may be hail and strong gusts of wind.
Further forecast, from now until June (focusing on May) is the period of weather transition from cold season to hot season, dry season to rainy season in the North, so strong thunderstorms with tornadoes, lightning, and hail may appear the most during the year.
In mountainous areas, the impact of terrain can create strong convective cloud nests, resulting in thunderstorms with tornadoes, lightning, hail and strong gusts of wind.
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