Since June 17, the middle and lower reaches of the Yangtze River, Guangxi, Guizhou and other places have experienced continuous heavy rainfall, and the precipitation in some areas is 2 to 3 times higher than that of the same period in normal years. According to the latest forecast of the Central Meteorological Observatory, from July 3, the rainfall in the middle and lower reaches of the Yangtze River and Guangxi will weaken and enter an intermittent period, and the main rain belt will be lifted north to Shandong, Henan, and northern Jiangsu and Anhui.
How does the precipitation process develop after the northward lifting of the rain belt? Is there a risk of a sudden turn in drought and flood? What should the affected regions do? The reporter interviewed Ma Xueyuan, chief forecaster of the Central Meteorological Observatory.
Q1: What is the scope and intensity of precipitation after the northward lifting of the rain belt?
As the subtropical high strengthens and extends westward to the north, from July 3 to 8, the main rain belt that has been maintained in the middle and lower reaches of the Yangtze River for a long time will lift north to the Huanghuai region, the precipitation in the middle and lower reaches of the Yangtze River will weaken significantly, the high temperature weather will develop in the central and eastern parts of the Yangtze River, and the area from Chongqing to the Huanghuai will be heavy to heavy rain, with local heavy rainfall, and thundershowers in North China and Sichuan Basin.
From the night of July 3 to 6, two heavy precipitation processes occurred in succession in the Huanghuai region on the north side of the subtropical high due to the influence of two shortwave disturbances. The eastern part of the Sichuan Basin, Chongqing, western Hubei, south-central and eastern Henan, southern Shandong, northern Jiangsu and Anhui have heavy to heavy rain, local heavy rain, the cumulative precipitation is 50 mm to 150 mm, and the local precipitation is more than 200 mm. From the 7th to the 8th, there will be heavy precipitation in the northeast of Northwest China, the central and southern parts of North China, and the central and northern parts of the Huanghuai River.
Q2: What is the impact of this precipitation on areas with high temperature and little rain in the early stage?
The precipitation is very beneficial to the growth of summer maize, summer soybean and other crops, but it is necessary to be vigilant against the possible risk of drought and flood and secondary disasters.
Taking Henan as an example, the precipitation process is beneficial to alleviate the drought in southern and eastern Henan, promote the growth of autumn crops at seedling stage and the vigorous growth of spring-sown crops, but the precipitation is unevenly distributed, and there is a risk of water accumulation in the farmland of local low-lying plots, and strong convective weather has an adverse effect on cash crops such as forest fruits and flue-cured tobacco.
At the same time, due to the large amount of accumulated precipitation in the near future, it is necessary to be vigilant against the lag of geological disasters. Guangxi, Hunan, Anhui, Jiangxi and other places have a high risk of flash floods and geological disasters, and Guangxi, Hunan, Henan and other places have a high risk of urban waterlogging, and the maximum inundation depth may exceed 0.5 meters.
In addition, the precipitation in the middle and lower reaches of the Yangtze River has weakened, and the water level in the Yangtze River basin has risen slowly, but it is still necessary to pay attention to the situation that the areal rainfall in some sub-basins of the Yangtze River basin and the Pearl River basin has reached the level of heavy rainfall.
Q3: How should localities take precautions?
North China, Huanghuai and other places need to pay attention to strong convective weather such as local heavy rainfall and thunderstorms and strong winds, and the middle and lower reaches of the Yangtze River and Guangxi and other places have the risk of heavy rain disasters, and it is necessary to pay attention to the secondary disasters that may be caused by heavy rainfall, so as to prevent the adverse effects of low visibility of rainfall, water accumulation on roads, and slippery roads on traffic travel. The public living in mountainous areas should pay special attention to meteorological forecasts and early warning information and meteorological disaster risk information such as flash floods, floods of small and medium-sized rivers, and various geological disasters in a timely manner, and prepare for prevention and response.
In addition, the middle and lower reaches of the Yangtze River will enter a period of intermittent rainfall, and the temperature in Jiangnan, South China and other places will rise significantly from the 4th, as if "the fire collects juice", and the heat is abnormal.
Author: Wu Tong Editor: Li Yue, Wang Wan, Wang Suqin
Release: Liu Jia Review: Duan Haoshu