Squall line is coming! Thunder, lightning, gale and hail are coming!

In recent years, Longyan, Fujian has experienced severe local convective weather several times. From the radar echo, it can be seen that a "squall line" has appeared.

So, what kind of line is a squall line?

(It is pronounced as [biāo] line, not [bāo] line)

Squall line is a member of the severe convection family.

He is definitely the powerful figure in the family!

Some people also call it the "aircraft carrier" in severe convective weather.

Is it really that powerful?

What is a squall line?

A squall line is a narrow severe convective weather belt with a small range, short life span, and sudden changes in air pressure and wind. When it comes, there will be severe weather phenomena such as sudden changes in wind direction, sudden increase in wind speed, sudden increase in air pressure, and sudden drop in temperature. Near the squall line, in addition to the violent changes in wind, air pressure, and temperature, there may usually be violent weather processes such as lightning, heavy rain, hail, and tornadoes.

Lai Qiaozhen, Director of the Longyan Radar Station in Fujian Province, explained why the squall line occurred in Longyan:

Today, a squall line swept across Longyan, and the whole city experienced strong convective weather such as strong thunderstorms, strong winds, short-term heavy rainfall and hail. Hail occurred in Gaopi Town and Hukeng Town in Yongding.

Squall lines are mostly caused by cold air moving to warm and humid areas, which creates a cold upper and warm lower pattern, making the upper and lower thermal structures of the troposphere different, resulting in high-intensity air convection. It mainly occurs from March to June, and mostly occurs in the afternoon and evening. This morning, rainfall in northwest Fujian caused low temperatures, and the temperature in the southeast rose rapidly in the afternoon, which increased the temperature gradient. Combined with the influence of mesoscale shear, squall lines occurred.

In response to the arrival of severe convective weather, Longyan promptly launched forecast and warning services and carried out 12 artificial hail prevention operations.

Where do squall lines appear in our country?

South China in March, Jiangnan in April-May, Huanghuai in June... In my country, with the advancement of the southwest monsoon, squall lines are likely to appear every year. This is because the southwest monsoon is unimpeded, and its abundant energy and water vapor create excellent conditions for the birth of squall lines.

From appearance to disappearance, the typical life cycle of a squall line is generally only 6-12 hours, but it often leaves traces with its huge destructive power. The most important thing to prevent squall lines is to look at the nowcast, so in the season when squall lines are prone to occur, the public needs to pay more attention to short-term nowcasts, and the meteorological department will also issue forecast warnings in advance.

When encountering severe convective weather such as thunderstorms, strong winds, hail, etc., stay away from easily broken trees, billboards, and dilapidated buildings.