The new cold wave hits, the temperature in many places will hit a new low this winter
Most areas of central and eastern my country may be in a low temperature state in the next 10 days; there will be a cold air attack from the 10th to the 12th
According to the statistics of the National Climate Center, since the beginning of winter (December 1, 2020-January 3, 2021), there have been two cold air processes affecting my country in December 2020, which were from December 13th to 15th (national type). Strong cold air) and December 29 to January 1 (national cold wave).
Compared with the same period in history, although the number of cold air (including cold waves) is not too high, these two times are national cold air processes with a large impact area and strong cold air intensity.
The Beijing News reported on January 5, a new wave of cold air arrived in my country, and the Central Meteorological Observatory issued a cold wave blue warning at 6 o'clock on January 5.
According to forecasts, from 20: 00 on January 5 to 20: 00 on 8th, my country's central and eastern regions will experience a wide range of cooling weather, and the lowest temperature in parts of the southern part of northeast my country, northern China, and Huanghuai will hit a new low since winter.
After that, from the 10th to the 12th, there was another cold air attack.
Experts from the Central Meteorological Observatory interpreted the cold wave process.
The temperature drop in Shanxi, Shandong and Zhejiang is larger
Since the beginning of winter, cold air has frequently flown southward into my country. The Central Meteorological Observatory has previously issued two rounds of cold wave warnings from December 12 to 14, 2020, and from December 27 to 31, 2020.
According to forecasts, this cold air process will affect most of the central and eastern part of my country from north to south on the night of January 5.
From 20: 00 on the 5th to 20: 00 on the 8th, affected by the strong cold air, the temperature in the central and eastern regions of my country will generally drop by 6°C to 8°C, among which parts of the western part of North China, eastern Huanghuai, eastern Jianghuai and eastern Jiangnan will cool down The range can reach more than 10℃.
Shanxi, Shandong, and Zhejiang all have relatively large cooling rates.
Although this cooling rate is slightly smaller than the "New Year's Cold Wave" from December 27 to 31, 2020, many places have undergone the previous round of cooling "rolling", and their "base temperature" is relatively low. This round of cooling is expected Afterwards, the lowest temperature in parts of the southern part of Northeast my country, northern China, and eastern Huanghuai will be the lowest since this winter.
Among them, the lowest temperature in Beijing, Dalian, Jinan and other places will be below -15℃, and the lowest temperature in Shenyang will drop below -25℃.
After this round of cooling, the 0°C line of the lowest temperature will be pressed south to southern Jiangnan to northern South China, and the -10°C line will be pressed south to Qinling to eastern Jianghuai.
Local blizzards in Xinjiang, Tibet, Qinghai and other places
In addition to "superimposing" low temperature on the "basic low temperature", the body feels colder during this cold air process.
According to the forecast of the Central Meteorological Observatory, the wind in the north is strong, and there will be northerly winds of magnitude 4 to 6 in the Yangtze River Basin and its north, and gusts of magnitude 7 to 9, especially in the Bohai Sea, the Yellow Sea and the East China Sea. Strong wind, gusts can reach level 10 to level 11.
However, the cold air process has not brought much rain and snow. It is expected that there will be moderate to heavy snow and local blizzards in southwestern Xinjiang, western Tibet, and southern Qinghai from the 5th to the 6th.
From the 6th to the 7th, there was light snow or sleet in southern Gansu, southern Shaanxi, western Hubei and eastern Southwest China, and most of the south of the Yangtze River. There was light rain in southeastern Jiangnan and southern China.
It is worth noting that after this round of cooling, most of the central and eastern parts of China may be in a state of low temperature in the next 10 days. In addition to the very low base temperature in the previous period, there will be a weak cold air from the 10th to the 11th. Going south, the recovery may still have to wait.
■ Interpretation
Two cold waves have been strong since the beginning of winter
According to the statistics of the National Climate Center, since the beginning of winter (December 1, 2020-January 3, 2021), there have been two cold air processes affecting my country in December 2020, which were from December 13th to 15th (national type). Strong cold air) and December 29 to January 1 (national cold wave).
Compared with the same period in history, although the number of cold air (including cold waves) is not too high, these two times are national cold air processes with a large impact area and strong cold air intensity.
Experts explained that since the beginning of winter, the middle and high latitudes of Europe and Asia have been controlled by the meridional circulation of “high west and low east”, and the East Asian winter monsoon is relatively strong, and this circulation pattern has basically remained unchanged in December. The "high west and low east" meridional circulation and the continuous strong winter monsoon are the direct causes of the low temperature in most areas of central and eastern my country since December 2020.
In addition, the recent peak of the La Niña phenomenon in the equatorial Central and Eastern Pacific and the lack of sea ice in the Arctic in autumn are two signs that cannot be ignored.
Historical statistical analysis shows that in most La Niña winters, the meridian of the atmospheric circulation in the middle and high latitudes of Europe and Asia is relatively large, and the cold air activities affecting my country are more frequent and strong than usual. The low probability is also greater.
In September 2020, the Arctic sea ice was unusually low (the second least in history).
Studies have pointed out that the lack of Arctic sea ice in September is conducive to the stronger Siberian high in winter.
Monitoring in the summer of 2020 shows that the atmospheric circulation in the Arctic region exhibits a typical negative AD phase, with its modal index reaching the lowest value in history. Therefore, this is also conducive to the stronger Siberian high this winter and the stronger East Asian winter monsoon.
In general, the most direct cause of the current low temperatures in most of the central and eastern parts of my country is the "high west and low east" meridional circulation and the strong East Asian winter monsoon. The lack of La Nina and autumn Arctic sea ice is the winter monsoon this year. Too strong provides an important background condition.
Beijing News reporter Li Yukun