On February 1, the China Meteorological Administration held a first-class ventilation meeting, focusing on the strongest rain, snow and freezing weather in winter since 2009, and invited experts from the National Meteorological Observatory, the National Climate Center, the Public Meteorological Service Center of the China Meteorological Administration, the Henan Meteorological Observatory, and the Wuhan Central Meteorological Observatory to answer questions from reporters.
According to the forecast, from January 31 to February 5, there will be a wide range of rain, snow and freezing weather in the central and eastern parts of China, with snowfall mainly in the north of the Yellow River and its vicinity, and rainfall in the south of the Yellow River and the middle and lower reaches of the Yangtze River. On February 1, the ** Meteorological Observatory continued to issue a blue warning for heavy snow, a blue warning for high winds, and a yellow warning for heavy fog. At 10 o'clock on the 1st, the ** Meteorological Observatory issued a freezing orange warning for the first time, which is the highest level of freezing warning issued by the station since the establishment of the freezing warning standard in 2010.
1.What is the cause of this widespread rain, snow and freezing weather?
According to the ** Meteorological Observatory, from February 1 to 5, there was snowfall in the eastern part of Northwest China, North China, Northeast China, Huanghuai and other places, and there was rain turning to sleet or snow in southern Huanghuai, southern Jianghan, western Jianghuai, northwest Hunan, northern Guizhou, northern and eastern Chongqing, and most of the above areas had moderate to heavy snowfall, and some areas had blizzards, local heavy snowfall or extremely heavy snowfall; There was moderate to heavy rain in most areas of the middle and lower reaches of the Yangtze River and south of the Yangtze River, and heavy rain in some areas. Among them, from the 1st to the 4th, there was continuous freezing rain in parts of southern Henan, Hubei, central and northern Anhui, northern Jiangsu, central and northern Hunan, eastern Guizhou, and southeastern Chongqing.
Widespread rain, snow and freezing weather in the central and eastern regions have been opened Photo: Mao Chenxu, Liu Fang, Ma Fang.
*Xu Jun, chief forecaster of the Meteorological Observatory, said that this process was produced by the combination of sufficient water vapor brought by the south-branch trough that deepened eastward and cold air in the middle and high latitudes of the north. Among them, the Jianghuai cyclone caused the heaviest snowfall period from the 3rd to the 5th. The affected area is mainly in the central and eastern parts of China, with snowfall in the north and near the Yellow River, and rainfall in the middle and lower reaches of the Yangtze River and its south.
According to Xu Jun's analysis, the strong warm and humid airflow and the cold air at the bottom led to continuous freezing rain in Guizhou, Hunan and Hubei.
Henan Province is in the center of the rain and snow weather process in this range, and it is also in the transition area of rain and snow transformation. From the afternoon of January 31 to the morning of February 1, moderate to heavy snow occurred in the northern and central parts of Henan Province. Gu Xiujie, chief forecaster of the Henan Provincial Meteorological Observatory, said that the precipitation phase in Henan Province is complex, with snowfall in the north, central and western regions, and east, sleet turning to pure snow in the southeast, and rain in the south. It is expected that on the 2nd, there will be light to moderate snow in most parts of Henan Province, and heavy to heavy snowfall in the west and southeast; Among them, the south of the Huai River was accompanied by freezing rain for some periods. On the 3rd and 4th, there was moderate to heavy snow in most parts of the province, heavy snowfall in the east and southeast, and localized heavy snowfall.
The freezing rain in the central part of Hubei was obvious and lasted for a long time. According to Gou Aning, chief forecaster of the Wuhan Central Meteorological Observatory, the rain and snow phases in this process are complex, with sleet, freezing rain, ice particles, and pure snow intertwined, and it is necessary to pay attention to the adverse effects on the Spring Festival.
2.Is it related to El Niño that such widespread rain, snow and freezing weather are rare?
Zhao Junhu, chief duty officer of the National Climate Center, said that historically, it is rare to have large-scale and long-lasting freezing rain and snow weather in China. The most impressive thing is that at the beginning of 2008, the southern region of China suffered a historically rare low-temperature rain, snow and freezing disaster, which was wide-ranging, intense, long-lasting and heavy-impacted. The most recent one was from January to February 2022, and there were many obvious rain and snow weather processes in southern China, but the scope was small, the intensity was weak, and the impact was smaller than that in 2008.
According to the latest monitoring by the National Climate Center, the peak of the moderate-intensity El Niño event that began in May last year occurred in December last year, and it is now in a recession period, and this event is expected to continue until the early spring of this year. Zhao Junhu said that according to statistics, the early stage of El Niño events has the most significant impact on the weather and climate systems of the tropics and the southern hemisphere. At the peak of development, it will affect the winter climate of the Northern Hemisphere.
Xinhua.
Although the temperature in most parts of China is close to normal to high in the winter of El Niño (there will be warm winters in some years), the cold air is active in stages, and the temperature fluctuates greatly. On the other hand, in the winter of El Niño, the intensity of the subtropical high in the northwest Pacific is stronger, and the water vapor conditions in the central and eastern parts of China are better, and the precipitation is likely to be more than that of the same period in normal years.
Therefore, the El Niño event is an important climatic backdrop for this widespread rain, snow and freezing weather. Zhao Junhu said.
3.What impact will this process have on the Spring Festival?
At present, it is the peak season of returning home for the Spring Festival, and the rain, snow and freezing weather have a heavy impact on railways, highways and aviation. Liu Yanxiang, chief of meteorological services at the Public Meteorological Service Center of the China Meteorological Administration, said that in terms of road traffic, low visibility caused by rain, snow and freezing weather may reduce drivers' ability to predict road conditions. Slippery roads caused by snow and ice can cause traffic jams or congestion. In aviation, low visibility and icy runway snow will also affect aircraft take-off and landing, causing flight delays; At the same time, it is also necessary to pay attention to the impact of aircraft ice causing instability in high-altitude flight.
In terms of railways, in addition to low visibility affecting the driver's judgment of road conditions, snow and ice on the railway may cause the rails to freeze and crack or deform, so it is necessary to be highly vigilant against the potential risk of ice at railway crossings affecting train operation. In addition, railway signalling systems and communication equipment may also be affected.
Liu Yanxiang suggested that the public pay close attention to the weather and road conditions, prepare in advance, and make reasonable travel arrangements.
4.Will the current round of rain, snow and freezing weather process come back after the end?
Xu Jun said that after the end of this round of rain and snow weather process, from February 6 to 7, there will be light to moderate rain in most parts of Jiangnan, South China, Sichuan Basin and northern Yunnan, among them, there will be sleet or snow in the eastern part of Northwest China, the western Sichuan Plateau, central and northern Guizhou and parts of northern Jiangnan.
The precipitation process from the 6th to the 7th was generally southerly, and the impact was not as good as this one. In the next 10 days, the temperature in most parts of central and eastern China will be low, and the temperature in most parts of the north will begin to rise on the 8th, while the temperature in the south will lag behind. Xu Jun said.
Author: Luo Lan.
Editors: Yang Aoqing, Wu Tong, Wang Suqin.
Review: Duan Haoshu.
*: China Meteorological Administration.