Sanfu is over, is the cool day coming?

On August 24th, Futian, which lasted for 40 days, was finally over. This year's high temperature did not know how many people had a good yearning for summer. Will the high temperature continue after the emission? Will the weather become cool? Will there be "autumn tiger"?

Let's put the conclusion first: the days when the high temperature is completely ended.

Seeing this conclusion, everyone may doubt that the weather forecast is really accurate now? Looking back at this summer high temperature weather, many people are paying attention to the weather forecast in the hot summer, hoping to have a heavy rainfall, bringing a short time. But whenever the heavy rain in the forecast is approaching, they suddenly disappear, or just a symbolic light rain, which is very disappointing.

why is that? Is the weather forecast not allowed? Maybe you don't really understand the weather forecast at all.

01

Uncertainty of weather forecast

Weather forecasting is uncertain. Modern weather forecasting and climate prediction are based on numerical weather forecasts. Such weather forecasts, its uncertainty comes from at least three aspects.

First of all, the initial value of numerical forecasting, including whether the actual observation can completely represent the current state of the atmosphere, as well as whether the actual observation can be used well in the mathematical equation of weather forecasting. This is the initial error.

The second is the establishment of a mathematical physical equation, whether it can truly simulate the various physical processes that affect the atmosphere of nature. For example, how the sun is transmitted to the atmosphere by heating through the ground; how the water in the atmosphere is transformed in phase transformations such as water vapor, cloud water, cloud ice, etc. This is the pattern error.

Finally, it is also the most fundamental impact of forecast uncertainty is non -linear or chaos. For a complex chaos system such as atmosphere, its randomness is natural. Atmospheric system.

In short, numerical weather forecasting is an approximation of future weather. Based on its forecast for future weather, its accuracy is destined to be relative, and it is absolutely not sure. Generally speaking, the larger the weather, the more trending the forecast, the higher the reliability; the more the weather system with a smaller scale, the more fine the forecast, the worse the reliability. Similarly, the closer to the time -effective forecast, the smaller the uncertainty; the longer the long -term forecast, the greater the uncertainty.

Summer high temperature is a typical large -scale weather. The reliability of its trend forecast is very large, but the details will still be uncertain. For example, when the high temperature weather trend was predicted last week, it was found that the high temperature in the north of the Yangtze River will end, and the high temperature in the Jiangnan region will also weaken significantly. But today, due to the lack of cold air strength, the high temperature of Jiangnan has weakened and slows down. However, a large -scale high temperature will be determined at the end of next week.

As mentioned just now, the weather caused by rainfall, especially the small and medium -sized weather systems such as thunderstorms, is even more uncertain.

02

Will the temperature fall?

Under the "torture" of the long and hot Fu Tian this year, many people are looking forward to the coolness after they are out. Just now we also learned about the uncertainty of weather changes, and Futian is just a rough range. It cannot judge the specific time and regional temperature changes through "entering" and "out".

However, from the past two days of warmth, cold air has fallen south of the East Road and crossed the Yangtze River. Although the cold air has weakened after crossing the river, it is enough to ease and even end the high temperature along the river in the middle and lower reaches of the Yangtze River.

On August 24th, cold air struggled south. Although its strength became weaker and weakened, the high temperature south of the Yangtze River could still weaken further. Since the cold air is south of the East Road, Zhejiang, the most strongest in the eastern part of the cold air forces, has also ushered in a sharp weakening of high temperatures, and even ended there. After the cold air passed through the Yangtze River, it gradually weakened the degeneration. In addition to most of the south of the river in central and northern Zhejiang, such as Hunan, Jiangxi, Fujian and other places still maintained high temperature weather. Similarly, the power of cold air to the Sichuan basin is also very weak, so Sichuan and Chongqing are still high.

On the remaining days, the cold air will be weakened and re -added. Although the power of high temperature this week is still strong, with the north -south pinch of the cold air and the typhoon "saddle", the subtropical high pressure of high temperature weather will also weaken day by day.

According to the latest meteorological data, the high temperature weather north of the Yangtze River will come to an end this week, and the high temperature weather in the south of the Yangtze River will also be expected to be ended around Tuesday. Essence It can be seen that the day is not far from the end of the high temperature of the second wheel.

03

What is the state of "autumn tiger" this year?

With the end of the strongest high temperature in this round of history, we can think that this summer's high temperature weather is here, but there will still be the possibility of phased high temperature weather in the southern region in the future.

According to the short -term climate trend forecast from September 5th to September 20th from August 22, except for central and southeast and southeast, most North China, eastern North China, northern China, and northern China, the temperature is lower than the same period of the year The temperature of the rest of the country is close to the same period of the year or higher.

This conclusion means that most of the south compared to the same period of the same year, and the warm, which means that the probability of "autumn tiger" is relatively high.

Taking Jiangxi, Zhejiang and other places as an example, in mid-September, the average annual temperature in most of the two provinces was 24 ° C-26 ° C, the average maximum temperature of the year was 29 ° C -32 ° C, and the extreme maximum temperature exceeded 37 ° C. Some areas in the local area. Even more than 40 ° C. The average temperature is high by 1 ° C-2 ° C, and the maximum temperature may be 3 ° C-4 ° C or more. This means that the maximum temperature has a high probability of above 35 ° C, that is, the weather of "autumn tiger" appears. However, even if the "Autumn Tiger" appears, its high temperature and high temperature in summer are not the same. The high temperature of the "autumn tiger" is mainly dry heat, and it is mainly hot during the day, and it will not be too torment at night. 04

Meteorological drought is developing

Although the high temperature is coming to an end, the drought caused by the high temperature and rainy rain may not end, and even develop.

The release of the Central Meteorological Observatory's continuous high -temperature warning began on July 21st. From August 12th, it was upgraded to a top high -temperature red warning, but the first meteorological drought warning was only one week after the high temperature red warning. Is this the "slow response" of the meteorological department?

Relative to the late warning of drought early warning is not because of the dullness of the meteorological department, but because of the complexity of meteorological drought, which includes its lagging relative to weather.

Drought disasters have been widely known to the public since ancient times. From the perspective of modern science, the problem of drought is very complicated, involving a wide range, and can generally be divided into meteorological drought, agricultural drought, hydrological drought, and economic and social drought.

Meteorological drought focuses on the comprehensive consideration of the comprehensive consideration of weather such as precipitation and evaporation, and measures drought;

The actual drought of agricultural drought focusing on the growth of crops;

Hydrological drought emphasizes the degree of dryness such as the river reservoir.

Among them, meteorological drought is the cause of other droughts, but the drought of weather does not necessarily cause other droughts immediately, but also affected by many factors. There is a complex relationship between them.

Because weather drought is closely related to the relationship between precipitation and evaporation for a period of time, the weakening and ending of high temperature is not necessarily the end of weather drought. As far as the drought of meteorological drought is still in development, it is still under development. According to the short -term climate forecast for the middle and mid -September, not only high temperatures in the dry areas of meteorology, but also may continue to rain.

However, in the face of the upcoming high temperature, it is still happy, and finally you can enjoy a cool weather.

Source: Science Popularization China

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