From June 22 to the morning of the 23rd, rainfall occurred in the western and northern parts of Hunan. Heavy rains occurred in Xiangxi Prefecture, Huaihua, Changde, Yueyang, Yiyang, Changsha, and Loudi. Some areas experienced heavy rains. On the 22nd, the precipitation in Taoyuan, Detaoyuan, refreshed the local historical extreme, ranking the fourth highest in Hunan history since complete meteorological records were established in 1961.
According to the current flood conditions and the relevant provisions of the "Hunan Provincial Department of Water Resources' Flood and Drought Disaster Prevention Emergency Response Work Procedures (Revised)", the Provincial Department of Water Resources decided to launch a Level IV flood prevention emergency response at 18:00 on June 22.
The Provincial Meteorological Observatory predicts that in the next week (from the evening of the 22nd to the 28th), there will be continuous heavy rains to heavy rains in northern and central Hunan, and local heavy rains. The comprehensive intensity of this round of rainfall is expected to be basically the same as the "extremely severe" heavy rain process from June 23 to July 2, 2017, which is highly extreme and has a high risk of disaster.
Why does it rain so many nights during this round of precipitation in Hunan? How will the weather develop later? Are many places in the south experiencing "violent plummeting" related to El Niño? When will this impact end?
High temperatures during the day and thunderstorms at night. Why does it rain so often in Hunan at night?
Night rain in the meteorological sense refers to rainfall during the period from 20:00 to 8:00 the next day. Statistics from the Hunan Provincial Climate Center show that from May to July every year, during the main flood season in Hunan, if there is night rain, the rainfall at night can often reach about 70% of the whole day, and the proportion of heavy rains is even higher.
The night rain is obviously intensified, first of all because there is abundant water vapor as "internal force" support. The jet stream strengthens at night, providing a steady stream of abundant water vapor.
In addition to sufficient raw materials, the rapidly rising temperature is also an important driver of the formation of night rain. Hunan has the same period of rain and heat. The rainy season is also a season when the temperature rises rapidly. During the day, the temperature rises quickly, energy is accumulated, and it is ready to go. Starting in the evening, the temperature in the upper air drops, and the temperature difference with the ground gradually widens. The upper clouds are colder and the lower parts are hotter, so the lower layers are warmer. Warm air rises, cools, and condenses into rain, which often pours down at night.
In addition, Hunan is surrounded by mountains to the east, west and south, forming an asymmetric "horseshoe-shaped terrain" that opens to the northeast, which amplifies the temperature difference and makes the movement between cold and warm air masses more intense, making the night rain like a powerful sprinkler car.
Heavy rains will continue for ten days, and the rainfall in Hunan is extreme
From Guizhou to the Yangtze River Delta, a "violent" Meiyu belt spanning thousands of kilometers has appeared. In the next ten days, four rounds of heavy rainfall in the south will seamlessly connect, even if the rain belt As it rises in the north and falls in the south, this area will be repeatedly "washed" by heavy rainfall.
Since the location of the rain belt is relatively stable, the rainfall continues to be strong, and the accumulated rainfall is large, we need to be especially vigilant that rainfall in northeastern Hunan, northern Jiangxi and other places will be extreme.
In the next 10 days (June 23 to July 2), the cumulative precipitation in southern Huanghuai, Jianghuai, Jianghan, Jiangnan, South China, southwest and eastern Tibet will be 50 to 150 mm, among which Hunan, eastern Hubei, Some areas in central and northern Jiangxi, central and southern Anhui, southern Jiangsu, northern and western Zhejiang, northern Guangxi, northwest Yunnan, and southeastern Tibet have 200 to 400 mm, and can reach more than 600 mm locally; eastern and northeastern Inner Mongolia The cumulative precipitation in the north and east, northern North China, eastern and southern Qinghai and other places has 30 to 70 mm. The cumulative precipitation in most of the above-mentioned areas was 30% to 70% higher than the same period in normal years, and the rainfall in some areas such as Jianghuai, northern and western Jiangnan, and northern Guangxi was more than double.
Many places in the south are experiencing "violent plum blossoms". How long will it continue to rain?
This week, the middle and lower reaches of the Yangtze River have entered the plum rain season. However, this plum rain is not like the continuous rain in everyone's impression. Instead, it is violent from the beginning. After the plum rain begins in Huangshan, Anhui Province, there are extremely heavy rains. The average rainfall is 11.2 times more than the same period in normal years. .
Not only the Yangtze River Basin, but also places such as Meizhou in Guangdong and Guilin in Guangxi have fallen into rare floods due to heavy rains. The 24-hour rainfall of Guilin’s 38 meteorological observation stations has broken the historical record since the establishment of the station.
△ Figure / Central Meteorological Observatory
The Central Meteorological Observatory predicts that before the end of June, heavy rainfall will mainly be located in the southern Huanghuai, Jianghuai, Jianghan, Jiangnan, western South China, southwest and eastern Tibet. Before the 27th, the rain belt will remain in the Yangtze River. areas near the middle and lower reaches. From the 28th to the 30th, the eastern section of the rain belt will expand northward, and there will be heavy to heavy rains and local heavy rains in the southern Huanghuai, Jianghuai and northern Jiangnan areas.
In the next 11-14 days (July 3-6), the cumulative precipitation in eastern North China, Huanghuai, Jianghuai, Jianghan, western South China, and southwest regions will be 30 to 60 mm, including parts of western Yunnan and southeastern Tibet. Areas have 70 to 100 mm.
Extreme weather occurs frequently, is this winter extremely cold?
Recently, the weather in the north and south has shown two extremes. With floods in the south and drought in the north, why are extreme weather so frequent?
Wang Chenghai, a professor at the School of Atmospheric Sciences at Lanzhou University, said that although the El Niño phenomenon is nearing its end, its impact has a lag. For example, in the past spring, the national average temperature was 1.4°C higher than the same period in normal years. It is expected that the temperature in most parts of my country will still be relatively high this summer. It is more likely that there will be an extreme high temperature heat wave similar to last year this summer, and it is also more likely that the extreme temperature will exceed last year.
When will this impact end? Wang Chenghai explained that the current climate change may last for 30-50 years, and we do not yet have effective technologies and ways to eliminate this change, so we can only slow down the damage and adapt to this change.
According to the latest forecast from the China Meteorological Administration, the world may enter a "La Nina" state in the second half of this year. Wang Chenghai said, “With the advent of winter, we may enter another state of frequent extreme weather. According to historical conditions, the winter when La Niña events occur is generally colder, which is about twice as likely to be warmer. Although the global winter is still on the high side, the probability of extreme cold events in my country in winter is indeed higher."
Xiaoxiang Morning News Comprehensive Report
