China Weather Network News Since May, heavy rains have occurred frequently in the south, with significantly more rainfall, short intermittent periods of rain and high overlap of rain areas, leading to rising water levels in some rivers, lakes and reservoirs and causing disasters.
At present, there have been 6 rounds of heavy rainfall in the south, and it is expected that another round of heavy rainfall will begin tomorrow (May 28). The public needs to strengthen prevention of secondary disasters caused by multiple rounds of heavy rainfall.
There are 6 rounds of rains in the south in May, and heavy rains will come again from the 28th
As of May 27, there have been 6 rounds of heavy rainfall in the southern part of May (May 2 to 4, May 10 to 12, May 13 to 16, May 19 to 20, May 21 to 24 May 26-27), many places encountered heavy rainfall accompanied by strong convection.
Zhang Juan, a meteorological analyst at China Weather Network, said that the six rounds of rainfall in the south were characterized by frequent heavy rains, short intermittent periods, significantly more rainfall, and high overlap of rainfall areas. Among them, the intensity was the most intense from May 13 to 16.
From May 13th to 16th, the accumulated rainfall in southern Huanghuai, Jianghuai, Jianghan, most of Jiangnan, northern South China, eastern Sichuan Basin, eastern Guizhou and other places reached 50-100 mm, southern Henan, southwest and eastern Hubei, southern Anhui , Southern Jiangsu, northwestern and southern Jiangxi, north-central Hunan, northwestern Guangxi, etc. in some areas up to 120-200 mm, and local areas such as Yichang and Enshi in Hubei 250-383 mm; these areas are accompanied by 8-11 thunderstorms. Hail occurred locally, and tornadoes occurred in Shengze, Suzhou, Jiangsu and Wuhan, Hubei.
Strong convective weather such as heavy rainfall, thunderstorms and strong winds for many days has caused damage to houses, broken trees, rising rivers, flooded roads, and urban waterlogging in some areas.
Zhang Juan introduced that the relatively strong rainfall in the south in May of the year was mainly concentrated in southern China, but this year it was concentrated in the south of the Yangtze River. The frequent heavy rainfall in the region is comparable to "the plum blossom", which is relatively rare. At the same time, strong convective weather has entered a high incidence period.
Usually in May, strong convective weather mainly occurs in the southern region, where the air flow between heating and cooling is fierce, which can easily cause disasters.
Judging from the characteristics of strong convective weather, the 13th to 16th was a mixed strong convective weather process, with large-scale lightning, short-term heavy precipitation, and even sudden and strong local tornadoes.
The Central Meteorological Observatory predicts that from 28 to 31, affected by cold air and low-level shear, the southern region will once again be accompanied by rain, and there will be moderate to heavy rains in most of the south of the Yangtze River, northern South China, and Guizhou, and heavy rains in some areas. Heavy rains will be accompanied by strong convective weather such as short-term heavy precipitation, thunderstorms and gales.
Zhang Juan reminded that from the end of May to the beginning of June, there were still heavy rainfall and strong convection weather in the south, and the overlap of rainfall areas was high, and the risk of disasters was high. It is necessary to be extra vigilant against secondary disasters such as mountain torrents, landslides, and mudslides that may be caused by frequent rainfall.
There are more rainfall and rainy days in the south than usual, breaking records
Since May, Jianghuai, Jiangnan and other places have been repeatedly hit by heavy rainfall. Both the number of rainy days and the accumulated rainfall have been significantly higher than usual.
For example, the number of rainy days in May in the Jianghuai and Jianghan areas is about 10 days, and the number of rainy days in the Jiangnan area is about 15 days. This year, the number of rainy days in parts of the central and northern Jiangnan, such as Zhejiang, Fujian, Jiangxi, Hunan, and Guizhou, reached 15 days. By 20 days, the rainfall will be 1 to 2 times more than that of the same period in normal years.
Take Jiangxi as an example. Since May, the province's average precipitation has been 1.6 times higher than that of the same period in normal years, which is a record high in the same period since the complete meteorological record in 1961.
Meteorological data shows that from 08:00 on May 1 to 08:00 on May 26, Nanchang accumulated precipitation of 390.4 mm, which was significantly higher than the average rainfall in May (219.5 mm); Shangrao was 554.7 mm, which was only 243 mm.
Zhejiang is about twice as high as that in the same period of normal years, the fourth most in the same period in history, and the most since 1973. Among them, Lishui and Taizhou both have the most in the same period in history.
Not only in the south of the Yangtze River, but also in northwestern Guangxi and western Fujian.
For example, Guilin, Guangxi, from 08:00 on May 1 to 08:00 on May 26, the cumulative rainfall reached 445.4 mm, 324.5 mm per year; Jianou, Fujian 526.3 mm, 238.1 mm per year.
Why is the rain so frequent?
Zhang Juan believes that so much rain in the south of the Yangtze River this year is mainly due to the fact that the subtropical high is stronger and more norther than in the same period of normal years, so warm and wet are transported to the northwest of Guangxi, Guizhou to the north-central part of Jiangnan, where they converge with cold air to form strong rainfall.
While most of South China, which should have been the previous flood season, especially in Guangdong and Hainan, under the subtropical high, the weather continued to be hot and muggy, with little precipitation and meteorological drought.
Judging from the current forecast, the southern part of Jiangnan and South China will become the most concentrated areas of rain in the next ten days. The accumulated rainfall in some parts of South China will be 100-180 mm, and the localized rainfall will be more than 250 mm. The drought and sultry feelings will be alleviated. , But we must also guard against the possibility of a sudden turn of drought and flood.
Frequent rains cause the water level to rise in some areas, the Yangtze River Hankou Station may reach its peak on the 28th
In recent days, heavy rainfall in the south has been frequent and the rainfall is more obvious, causing the water level of parts of the middle and lower reaches of the Yangtze River to rise rapidly.
According to a report from Chutian Metropolis Daily, yesterday morning, the water level at Hankou Station on the Yangtze River broke through the 25-meter waterproof level.
After a whole day of ups and downs, it rose to a maximum of 25.09 meters at 9 o'clock last night, which was also the highest water level in May during the same period in history.
At present, the water level of the Wuhan section of the Yangtze River continues to rise, mainly due to the previous continuous rainfall in the Xiangjiang River Basin.
As of May 24, the entire line of the Xiangjiang River in the Dongting Lake system had exceeded the warning level.
Beginning on the 24th, the water level of the Xiangjiang River dropped, and the stations gradually withdrew from the warning water level.
The Xiangjiang flood peak flows into the Yangtze River through the exit of Dongting Lake. It is expected to pass through Wuhan in these two days, so there will be a small peak in the water level at Hankou Station in these two days.
At present, the inflow of the Three Gorges reservoir area is about 16,000 cubic meters per second, and the discharge flow is approximately 10,600 cubic meters per second. Without increasing flood discharge in the Three Gorges reservoir area, it is expected that the water level at Hankou Station will reach its peak on the 28th and then begin to fall.
In the face of the current hydrological situation, at 18:00 on May 24, the Meteorological Center of the Yangtze River Basin has launched a Grade IV emergency response to flood control of the Yangtze River.
Zhang Juan reminded the local area to closely monitor the water levels of rivers, lakes and reservoirs, and prepare for flood control.