Rainfall may last for 70 hours! Why is heavy rainfall "stuck" in the Beijing Tianjin Hebei region? Shanxi | Precipitation | Beijing Tianjin Hebei
Affected by the residual circulation of Typhoon Dussuri, precipitation in the North China and Huanghuai regions has gradually spread since July 29th. At 10:00 on the 30th, the Central Meteorological Station continued to issue a red warning for rainstorm and a yellow warning for severe convective weather. As of the afternoon of the 30th, the rainfall in Hebei has reached the magnitude of extremely heavy rainstorm.
What are the characteristics of this precipitation process? What is the impact? The reporter interviewed Fang Chong, the chief forecaster of the Central Meteorological Observatory.
Reality:
Strong precipitation has occurred in Beijing, Tianjin, Hebei, Jin, Shandong, Henan and other areas
The meteorological monitoring showed that from 8:00 on the 29th to 8:00 on the 30th, heavy rain or rainstorm was widespread in central and southern Beijing, central and southern Shanxi, central and northeastern Hebei, Tianjin, Henan, and western Shandong, among which heavy rainstorm and local extremely heavy rainstorm occurred in eastern Shanxi, central and southern Hebei, and northern Henan.
From 9:00 on the 29th to 11:00 on the 30th, the maximum precipitation in the Beijing Tianjin Hebei region occurred in Zhaozhuang and Liangjiazhuang, Lincheng, Xingtai, at 583.8 millimeters. At 17:00 on the 29th, the maximum hourly rainfall intensity occurred in Juancheng, Shandong, at 86 millimeters.
From 20:00 on the 29th to 11:00 on the 30th, the average precipitation in Beijing was 39.1 millimeters, and the average precipitation in the urban area was 38.8 millimeters; The maximum precipitation occurred in the Three Rivers of Fangshan, with a precipitation of 143.8 millimeters; The maximum hourly rainfall intensity occurred in Beishicao, Shunyi, at 41.7 millimeters. From 8:00 on the 28th to 7:00 on the 30th, the precipitation of 313 stations in Tianjin reached rainstorm, 115 stations heavy rainstorm and 7 stations extremely heavy rainstorm. From 20:00 on the 28th to 7:00 on the 30th, a total of 1164 stations in southern Baoding, southern Langfang, Shijiazhuang, northeastern Cangzhou, Xingtai, and Handan in Hebei Province experienced precipitation exceeding 100 millimeters.
Features:
Long duration, high cumulative rainfall, and high risk of disaster
This round of precipitation is mainly characterized by stable precipitation, long duration, large cumulative rainfall, and high risk of disaster.
The residual circulation of Typhoon Dussuri entered Henan on the night of the 29th and continued northward. At this time, there is a subtropical high pressure system stretching westward in the eastern sea of the Beijing Tianjin Hebei region, while a high pressure ridge gradually moves eastward in the west. On the evening of the 29th, two high pressure systems in the eastern and western parts of the Beijing Tianjin Hebei region were connected, forming a "high pressure dam" in the northern part of North China, blocking the northward movement of "Du Suri".
Therefore, the duration of "Du Suri"'s stay in the North China to Huanghuai region will increase, resulting in a long duration and accumulated rainfall. Taking Beijing as an example, the intermittent heavy rainfall process will continue until the morning of August 2nd, and the duration may exceed 70 hours.
"Du Suri" itself carries a large amount of water vapor and is well supplied - the subtropical high pressure existing on its eastern side creates a strong pressure gradient between the two, with significantly increased easterly and southeasterly winds in the Beijing Tianjin Hebei region. Water vapor is transported smoothly and unobstructed northward; In addition, the typhoon "Kanu" in the western Pacific Ocean has become a climate, and the strong southeast wind will continuously transport the water vapor near "Kanu" to the North China Plain from a long distance. Two water vapor channels bring unusual water vapor conditions, resulting in significant precipitation.
In addition, the Taihang Mountains to the west of Beijing Tianjin Hebei collide positively with the easterly and southeast winds carrying water systems, and the Yanshan Mountains to the north also intersect with the water vapor channel. Water vapor is blocked and lifted by the terrain, concentrating in front of the mountains to form extreme heavy precipitation. The process is hindered, water vapor is abundant, and the terrain is favorable, resulting in extreme precipitation in the Beijing Tianjin Hebei region.
Reminder:
Preventing secondary disasters that may be caused by extreme heavy rainfall
Meteorological experts remind that although the precipitation this time may not reach the intensity of severe convective weather, it must not be taken lightly. Urban waterlogging, farmland waterlogging, floods in small and medium-sized rivers, geological disasters caused by mountain floods, rail transit, shipping and other meteorological risks are high. It is recommended to take preventive measures in advance.
The public needs to pay attention to nearby forecasts and warnings, take relevant defense measures in a timely manner based on changes in rainfall and flood conditions, and avoid dangerous areas such as mountainous areas, rivers, and geological hazard areas. Vehicles should avoid high-risk traffic and meteorological disasters when traveling, and drive with caution to avoid wading in water. The risk of waterlogging disasters in farmland is high in Beijing, Tianjin, Hebei, western Shandong, northern Henan, and eastern Shanxi. Various regions should promptly clean up farmland ditches and prepare for emergency drainage in advance.
This round of rainfall has a strong water surface, and soil supersaturation can easily lead to slope instability, posing a high risk of geological disasters. Meteorological experts suggest doing a good job in the defense and rescue of disasters such as flash floods, landslides, and mudslides.
