Central Meteorological Observatory: A new round of cold air strikes, and the south will welcome the strongest rainfall since the flood season.

Source: Xinhuanet
Although it has been in long summer, the cold air in China is still active recently. The reporter learned from the China Meteorological Bureau that from May 9 to 13, the north was disturbed by cold air, but the southern part of the Yangtze River and southern China will experience the strongest rainfall since the flood season this year. This process has the characteristics of long duration, large accumulated rainfall and fierce local rainfall.
The heavy rainfall in the south is ready to go, and the north is full of coolness. How to strengthen disaster risk prevention? Does it have an adverse effect on spring ploughing and sowing? Chen Tao, chief forecaster of the Central Meteorological Observatory, interpreted this.
Long-term confrontation between cold and warm air leads to long rainfall time and heavy rainfall.
According to the forecast of the Central Meteorological Observatory, it is predicted that the rainfall in the southern region will increase in the coming week. Among them, from May 9 to 13, southern Jiangnan and southern China will experience the strongest rainfall since the flood season this year. There will be heavy rain in most areas south of the Yangtze River, heavy rain in parts of South China and South Jiangnan, and heavy rain in Guangdong and Guangxi. These areas are accompanied by strong convective weather such as short-term heavy precipitation, thunderstorms or hail.
Chen Tao said that the strongest rainfall period in the process will occur from 10th to 12th, with precipitation concentrated in southern Jiangnan and southern China, and the daily rainfall at individual stations in Guangdong and Guangxi may reach historical extremes.
The main reasons for the heavy rainfall process in the south are: first, the subtropical high in the western Pacific is stable, the warm and humid airflow at its western edge and the cold air in the north continue to meet in Jiangnan and South China, and the cold and warm air confront each other for a long time, which leads to the long duration of the rainfall; Second, the southwest water vapor transport in the lower atmosphere in southern China has been significantly enhanced recently. Affected by the cyclone storm in the Bay of Bengal, it is more conducive to the water vapor transport to the south of China and provides sufficient water vapor conditions for this rainfall.
When the south enters rainy season, the risk of disaster is increased and attention is paid to prevention.
Affected by continuous heavy rainfall, the meteorological risk of mountain torrents and geological disasters in eastern and northern Guangxi, central Guangdong, southwestern Fujian, southwestern Jiangxi and southern Hunan is high; The meteorological risk of floods in small and medium-sized rivers in central Guangdong and eastern Guangxi is high. Chen Tao suggested that the above areas should pay attention to prevent the meteorological risks of mountain torrents, geological disasters and floods in small and medium-sized rivers that may be caused by heavy rainfall.
In addition, according to the forecast of the National Climate Center, this year’s South China Sea summer monsoon will break out in the third season (10th to 15th) in May, slightly earlier than normal (4th season in May), and its intensity is close to normal to weak. Under normal circumstances, within two weeks after the onset of the South China Sea summer monsoon, the monsoon airflow will carry more abundant southwest warm and humid water vapor from the tropical Indian Ocean and the South China Sea to the East Asian continent, and the convective heavy precipitation in the southern region will increase significantly, and the southwest rainy season and plum rain will begin one after another.
Therefore, when the south enters a rainy period, the risk of disaster increases, and extreme weather may occur, so preparations for disaster prevention and relief should be made in advance. Chen Tao said that the public should pay attention to the rolling meteorological forecast and early warning information released by various places and try to avoid going out during periods of heavy rainfall and strong convective weather.
Cold air affects frequently, and many places in the north are full of coolness.
Although long summer has passed, cold air is still active recently. Under the influence of cold air, the temperature in many places in North China Plain in these two days was obviously lower than that in the same period of normal years. On the morning of May 8, affected by cold air and rainfall, the temperature in Beijing, Shijiazhuang, Hebei and other places hovered at 10 degrees Celsius, and the body felt cold.
The Central Meteorological Observatory predicts that there will be a strong cold air activity in northern China from 10th to 12th. By then, the temperature in Inner Mongolia and most parts of northwest, northeast and north China will drop by 4 to 8 degrees Celsius, and the local temperature will drop by more than 10 degrees Celsius, accompanied by northerly winds of 4 to 6, and gusts of 7 to 9. Chen Tao said that due to the frequent influence of cold air, the temperature in many places in the North China Plain will continue to be low in the coming week, reminding the public to appropriately increase clothes according to the temperature forecast.
In addition to the strong wind cooling, some areas in the north will be accompanied by precipitation weather, and there will be small to moderate rain or thunderstorms and local heavy rain in Inner Mongolia and northwest, north China and northeast China. Low temperature combined with rainfall leads to lower somatosensory temperature.
Spring ploughing and spring sowing are generally smooth, and cooling and precipitation temporarily hinder the process.
Since spring sowing, the weather has been good in most parts of the country, which is conducive to the development of spring ploughing and spring sowing. At present, the progress of spring sowing of grain crops in China has been more than half, faster than the same period last year; Among them, the sowing and planting of early rice has ended, with more than 80% of spring wheat, 70% of spring corn and 20% of soybeans, and the overall progress is smooth. Cotton, spring corn, soybean and one-season rice in Xinjiang, North China, Huanghuai and other places are still being planted.
The process of precipitation cooling in central and eastern China from 9 to 13 is beneficial to supplement soil moisture in northern China, but the spring sowing operation will be temporarily blocked due to precipitation. The average temperature in the northern part of Northeast China, northern part of North China, eastern Gansu, central Shaanxi and other places is below 8 degrees Celsius, and the sowing of dryland crops such as corn and soybeans is suspended, and the germination rate of sown crops is slowed down.
Chen Tao suggested that the northeast region should avoid cooling and windy periods as much as possible, and plant seeds in time according to moisture and temperature changes. In areas with wet soil, pay attention to stepping up moisture removal after the weather improves; For the sown crops in dry land, attention should be paid to field inspection, and remedial measures should be taken in time once powder seeds are found; It is not advisable to transplant rice seedlings early in rice planting areas, pay attention to regulating the temperature and humidity in the seedling shed, and do a good job of wind protection and reinforcement. Areas that have not yet completed the sowing plan should seize the favorable weather, sow while the soil moisture is growing, and speed up the progress of spring sowing. Do a good job in seedling management of sown fields, and check and replenish seedlings in time.
For the southern region, heavy rainfall and strong convective weather are easy to cause rice lodging and short-term waterlogging in farmland, which is not good for harvesting and drying rape in southern Jiangnan. All localities need to clean ditches in time to ensure smooth drainage and reduce the impact of waterlogging.
Producer: Zhu Yonglei and Qiu Xiaomin
Planning: Li You
Reporter: Yu Ziru Wang Meili
Video shooting and production: Chen Zheng Zhang Yubo
Editor: Yang Liu
Xinhuanet and China Meteorological Network jointly produced.