Meteorological department analyzes why there are strong tornadoes and heavy hail in Guangzhou

On the afternoon of the 27th, due to the influence of strong convective clouds, a strong tornado and large hail with a diameter greater than 5 centimeters appeared locally in Guangzhou. On the late night of the 27th, the Guangdong Provincial Meteorological Bureau reported four reasons for the occurrence of this extreme weather.

Around 15:00 on the 27th, a tornado appeared near Liangtian Village, Zhongluotan Town, Baiyun District, Guangzhou City. The Guangdong Provincial Meteorological Bureau organized an expert team to conduct on-site disaster investigation and preliminarily surveyed the impact path of the tornado, which is about 1.7 kilometers long. The maximum impact width is about 280 meters, and the preliminary assessment shows that the tornado intensity is a strong tornado level.

Tornado is a rare local, small-scale, and sudden strong convective weather that occurs under extremely unstable weather conditions. Preliminary analysis by the meteorological department shows that there are four reasons for the occurrence of strong tornadoes and heavy hail in Guangzhou this time:

Firstly, in the past period of time, the warm and humid airflow from the southwest of the South China Sea has continued to strengthen, transporting a large amount of water vapor and energy to Guangzhou. Guangzhou has been in an unstable state of high temperature and humidity for a long time, and a large amount of unstable energy has accumulated near the ground.

Secondly, on the morning of the 27th, the warm and humid air flow in the near surface continued to increase, and multiple meteorological observation stations recorded abnormally high absolute humidity.

Thirdly, during the daytime on the 27th, the low-level jet strengthened, exacerbating the unstable layer structure of “cold above and warm below”.

The fourth is that the mesoscale convergence line on the ground and the passage of high-altitude fluctuations serve as triggering conditions, triggering strong updrafts and causing the mother storm of the tornado to develop strongly.