Original title: Rainfall in many places broke the historical extreme value: the rainy season in North China just started this year, the precipitation intensity/long duration Source: Kuai Technology
In the past few days, the North China and Huanghuai regions have ushered in the heaviest rainfall during the flood season. In this round of rainfall, the average rainfall in Beijing exceeded 100 mm. According to the forecast of the Meteorological Department, this round of precipitation is the beginning of the rainy season in North China this year, and the rain will be frequented during the “seven lower and eight upper” periods.In the past few days, the Beijing-Tianjin-Hebei region has experienced heavy rainfall, and the rainfall in some places has even exceeded the historical extreme.
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Data from the Central Meteorological Observatory on the 12th showed that from an extreme point of view, local rainfall in Handan, Hebei, Jincheng and Changzhi in Shanxi, Jiyuan, Anyang and Hebi in Henan reached 220-342 mm (the maximum hourly rainfall was 102-125 mm).
In addition, the daily rainfall of 7 national stations in central and southern Hebei and northern Henan exceeded the extreme value in July. Among them, Jize (206.4 mm) in Hebei and Huaxian (211.7 mm) in Henan exceeded the historical extreme since meteorological records.
According to the precipitation (mm) from 18:00 on the 11th to 19:00 on the 12th released by the Beijing Meteorological Observatory: the city’s average is 100.4, the urban average is 113.2, the southwest is 107.1, the northeast is 102.7, the northwest is 97.4, and the southeast is 75.8. The city’s largest Chaoyang Sunhe Station is 164.1, and the city’s largest Yanqing Haizikou is 197.2.
Meteorologically, precipitation with a 24-hour precipitation greater than 25 mm is called heavy rain; 24-hour precipitation with a precipitation greater than or equal to 50 mm is called heavy rain. This time, the average precipitation in Beijing has reached the torrential rain level, which also led to a significant reduction of flights at the two major airports in Beijing on the 12th, and the suspension of many bus lines at the same time.
Regarding this issue, Zhang Fanghua, chief forecaster of the Central Meteorological Observatory, said to the media that this round of heavy rainfall has the characteristics of wide impact, high rainfall intensity, long duration, large accumulated rainfall, accompanied by strong convection and windy weather, and high disaster risk.
From the point of view of causes, this heavy rainfall process was affected by a deep low vortex system. The east side of the low vortex is accompanied by a strong low-level jet, which brings abundant water vapor and unstable energy, which is very conducive to the production of heavy precipitation. The low vortex system moves slowly and the precipitation time is longer, which is conducive to the increase of accumulated precipitation.
In addition, the low-level jet stream converges and rises on the windward slope of Taihang Mountain, which is also conducive to local production of stronger precipitation.
In addition, corresponding to the low vortex, there is a cyclone system on the ground, with a large pressure gradient on the east side, which is conducive to generating strong ground winds. At the same time, this process was accompanied by convective thunderstorms. The two reasons are superimposed, and the windy weather in this process is also very obvious.
In the coming week, the main precipitation belt will be concentrated in the east of Southwest China to North China, Huanghuai, and Northeast China, with a southwest-northeast trend. The weather in the southern region, especially the Jianghuai, Jiangnan, and South China areas will be dominated by high temperature and little rain.
Meteorological experts reminded that immediately entering the “seven lower and eight upper” stage, the precipitation weather in North China and Northeast China is showing an increasing trend. The public should pay attention to the upcoming weather forecast, and should minimize unnecessary trips and do not go to mountainous areas, rivers, and areas with hidden geological hazards.