According to the forecast of the ** Meteorological Observatory, from February 17th to 22nd, affected by the cold wave, the temperature in most parts of China will experience drastic ups and downs, accompanied by a wide range of rain and snow, and there is still freezing rain in Henan, Hubei, Hunan, and Guizhou.
This process is hitting the peak of the Spring Festival return journey, what is its intensity? What impact will it have on transportation, energy supply, human health, etc.? In response to the issues of public concern, Zhang Fanghua, chief forecaster of the ** Meteorological Observatory, and Li Xiaozhu, senior engineer of the Public Meteorological Service Center of the China Meteorological Administration, gave a comprehensive interpretation.
The freezing rain is weaker than the previous round, but it should not be underestimated
The key word that touched the public's nerves the most in this process was "freezing rain". Before the Spring Festival this year, there will be a wide range of continuous rain, snow and freezing weather in the central and eastern parts of China. At 10 a.m. on February 1, the ** Meteorological Observatory issued the highest level of freezing warning since the establishment of the freezing warning standard in 2010 for the first time - the freezing orange warning. Heavy snowfall and freezing rain have not only become "roadblocks" for safe travel on the way home, but also brought great challenges to communication and power supply, leaving many people with lingering palpitations.
What can put the hanging heart a little at ease is that the freezing rain in this process is weaker in intensity and shorter in duration than in early February.
Freezing rain is formed when snowflakes and ice crystals falling from high altitudes completely melt into droplets after entering a warmer "melt layer", and then fall into a near-surface layer with a temperature below zero to freeze. Zhang Fanghua said that when the temperature in the lower layer of the rain and snow process dropped, the "melting layer" in the cloud was relatively shallow, and the intensity of freezing rain was not very large, but the impact on the return peak of the Spring Festival should not be underestimated.
From February 18 to 22, rain will turn to sleet or snow in Northeast China, the eastern part of Northwest China, most of North China to the eastern part of Southwest China, and the northern and western parts of Jiangnan. Shanxi, Shaanxi, Henan, Shandong, Heilongjiang, Jilin and other parts of the region have heavy to heavy snowfall, local heavy snowfall; There are moderate to heavy rains in the southern part of Huanghuai, Jianghuai, and the central and northern parts of Jiangnan, accompanied by strong convective weather such as thunderstorms, short-term heavy precipitation, and local hailstorms.
It is worth noting that due to the strong low-level jet stream, water vapor and unstable energy, the rainfall and convective weather in the southern region are more obvious, especially from the 19th to the 21st. Li Xiaozhu introduced that according to the comprehensive highway traffic safety management and control risk early warning products, from 8 o'clock on February 18 to 8 o'clock on the 23rd, a wide range of freezing rain and snow weather processes in the central and eastern parts of China will have an adverse impact on the return of traffic during the Spring Festival.
Among them, on the 18th, affected by snowfall or sleet, the risk of ice and snow accumulation on some sections of the highway in Heilongjiang, Jilin, and Liaoning was higher; From the 19th to the 22nd, some sections of Beijing-Hong Kong-Macao, Changshen, Daguang, Erguang, Lianhuo, Shanghai-Chongqing and other expressways in Hebei, Shanxi, Shaanxi, Shandong, Henan, Jiangsu, Anhui, Jiangxi, Hubei, Hunan, Guizhou and other places were affected by snowfall, sleet and freezing rain, and the risk of icing in the road sections was high, and it is expected to reach the second level and above control risk of highway traffic safety.
In addition, affected by the rain, snow and low temperature weather brought by the cold wave, the electricity demand in the southern region has increased, and it is expected that after the 20th, the power load in most parts of the southern region will be significantly higher than that of the same period in history; At the same time, from the 18th to the 22nd, there is a risk of transmission line icing in Northeast China, Central and North China, Central China, and Eastern Southwest, among which from the 20th to the 22nd, the icing thickness of local power lines in Guizhou, Hunan, Hubei, Anhui and other places may exceed 20 mm, which will have a certain impact on the safety of power facilities.
Meteorological experts suggest that it is necessary to focus on preventing the adverse impact of road icing on the return of Spring Festival transportation, and at the same time do a good job in energy storage and allocation, power facilities maintenance and ice melting preparations in advance to ensure energy safety.
A "roller coaster" of temperatures can pose health risks
It is worth mentioning that the temperature change in this process is drastic, which can be called "twists and turns".
Opening the national temperature change map from February 15 to 16, the "blue in the south and red in the north" are distinct, but the temperature in most areas can reach more than 6 to 8 regardless of the range of fluctuations.
With the cold wave moving south, from the 17th to the 22nd, the temperature in most parts of China will drop by 8 to 12 from north to south, and the temperature in some areas will drop by 12 to 18, and the local temperature in Inner Mongolia, Northeast China and Central China will reach more than 20.
From the 16th to the 17th, there were heavy to heavy snowfalls, local heavy snowfalls or extremely heavy snowfalls in Altay, Tacheng, Ili River Valley, and the western mountainous areas of southern Xinjiang in Xinjiang, and the main heavy snowfall period was the 16th; Affected by the cold wave, the temperature in most parts of Xinjiang dropped by 8 to 16, and the temperature in some parts of northern Xinjiang could reach more than 20. Winds of force 5 to 7 prevail in most areas, and winds of force 12 and gusts of 13 to 15 in the Yamaguchi area.
From the 21st to the 23rd, the daily maximum temperature in most parts of North China, most of the Huanghuai, western Jianghuai, Jianghan and central and northern Hunan will drop to 0 or below, which is significantly lower than that of the same period in normal years, and some areas are extreme.
Around the 23rd, the minimum temperature 0 line will be pressed south to Jiangsu, southern Anhui, northern Jiangxi, southern Hunan, southern Guizhou, and the minimum temperature in North China, Huanghuai to Jiangnan and other places is lower than that of the same period in normal years. The reason why the temperature dropped so drastically is also related to the intermittent warming of cold air from the 16th to the 18th.
Due to the strengthening of low-level southerly winds and the strong warm advection in the central and eastern parts of China, the temperature has risen significantly, and the daily maximum temperature is significantly higher than that of the same period in normal years, and there is a certain extremity. However, the warming force is far from being able to withstand the cooling force - this round of cold air can reach a minimum temperature of about minus 44 above 500 hPa, so its southward movement can be described as a bamboo, and the temperature that has finally risen will be "beaten back to its original shape" or even lower.
Taking Wuhan, Hubei Province as an example, the maximum temperature on February 18 could reach 24, but the maximum temperature on February 22 was only 1. Drastic changes in temperature in a short period of time can easily induce respiratory diseases such as colds.
Li Xiaozhu said that due to the influence of cold air, from today, from the northern part of Xinjiang, the central and northern parts of the northwest region to most of the central and eastern parts of China, there will be a high meteorological risk of influenza. Considering that the coming week will still be the peak time for return travel, it is recommended that susceptible people pay attention to cold protection and warmth, and wear masks as much as possible in crowded places to prevent the occurrence of influenza. Starting on the 24th, the temperature in the northern region will rise; However, due to the long period of cold air lingering in the southern region, the temperature did not rise slowly until around the 26th, and the magnitude was not large.
*: China Meteorological Administration.
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