◎He Liang, our reporter

　　In early September, this year's No. 13 Typhoon "Kang Sen" and No. 14 Typhoon "Santo" occurred one after another.

Affected by factors such as the subtropical high pressure, the westerly trough, and the Fujiwara effect of the twin typhoons, the typhoon track and intensity forecasts have become extremely complicated.

　　Since its formation on September 7th, "Sandu" quickly strengthened into a super typhoon on the 8th, and its intensity development exceeded expectations. It is rare that it strengthened so quickly.

The senior engineer of the Central Meteorological Observatory introduced to Chunyi that the sharp increase of "Sando" not only affected its path changes, but also caused a huge difference in the intensity of the two typhoons.

　　On September 9, there was a significant adjustment in the forecast of the "Sandu" path. One of the key factors was the time and location of the eastward retreat of the subtropical high.

Not only that, the eastward retreat of the subtropical high has slowed down the movement of Typhoon No. 13 "Conson".

　　"In fact, the time and position of the eastward retreat of the subtropical high may deviate greatly from the model prediction, leading to errors in the prediction of the speed and path of the typhoon movement. In addition, during the eastward transition of'Sandu', It may also be affected by the west wind trough to the north. The west wind trough is also affected by the eastward retreat of the subtropical high. It can be seen that the subtropical high moved the whole body as soon as it was pulled." Xiang Chunyi said.

　　In addition to the subtropical high and the westerly trough, the double typhoon effect is also an important factor.

　　At present, the distance between "Consen" and "Santo" is 1,100 kilometers. According to the principle of the Fujiwara effect, two typhoons may be restrained and rotated within 1,200 kilometers apart, just like the two ends of a seesaw are constantly pulling.

Xiang Chunyi said that under the effect of two typhoons, the two typhoons will compete for water vapor energy as much as possible.

"Santo" may be absorbed by "Conson" under the action of dynamic suction to dominate the world; although "Conson" will be dispersed by the Philippine island topography in the early stage, it is likely to strengthen into a severe tropical storm class typhoon again after entering the South China Sea. In the process of wandering and adjusting in the Xisha waters, there is enough time to reorganize and adjust the accumulated energy.

　　At present, "Conson" is close to Hainan, can it alleviate the drought in South China?

　　Xiang Chunyi said that "Conson" may not be able to solve the current drought in South China alone.

Its ability to alleviate drought in Hainan, Guangdong and other places is limited. The main reason is that after Kangsen approaches Hainan Island, it is affected by strong high-level wind shear. Its main convective clouds may be on the east and south sides, and the overall precipitation may not be able to Landed in places such as Hainan Island and Guangdong.

However, we still need to be vigilant about the impact of wind and rain on the Xisha region.

　　At the same time, on the morning of September 9, many Beijing residents were awakened by the rumbling thunder.

　　Monitoring showed that from 8:00 on the 8th to 7:00 on the 9th, there were moderate to heavy rains in eastern Inner Mongolia, southwestern Heilongjiang, central and western Jilin, central and northern Liaoning, and southern Beijing. There were thunderstorms of magnitude 8 to 10 on the ground, and severe convective weather such as hail appeared locally in Liaoning.

　　It is not only North China, Northeast China, and Inner Mongolia that have been "harassed" by strong convection.

In recent days, strong convection has also caused a wave of presence in southern Zhejiang, northern and southeastern Fujian, and western Yunnan, bringing strong local convection such as strong local precipitation, strong winds, hail, tornadoes, and lightning.

　　According to the Central Meteorological Observatory's forecast, starting on the 9th, in the next three days, strong local convection will also play a leading role in North China, Northeast China, and eastern Inner Mongolia.

　　According to Liu Xinhua, a senior engineer at the Central Meteorological Observatory, the strong convection in North China, Northeast China, and eastern Inner Mongolia is the result of the typical Northeast Cold Vortex "doing things" at home.

Under the control of the northeast cold vortex, a stream of cold air invades southward from time to time, converging with warm and humid air to form a stratification of warm and unstable upper and lower air, and strong convection under strong upward dynamic conditions.

　　In addition to the northeast cold vortex, the recent subtropical high not only has troubled typhoon forecasts, but some disturbances on its edges have also brought strong local convection to Zhejiang, Fujian, Yunnan and other places.

　　Liu Xinhua reminded that the recent period is still in a period of high incidence of strong local convection. The public can learn the latest weather forecast information through multiple channels in advance, especially pay attention to rolling forecasts and nowcasts, make good travel plans, and at the same time, appropriately reduce going out and avoid high impacts. Area, and have a certain knowledge of emergency self-rescue in advance.

　　(Science and Technology Daily, Beijing, September 9th)