How to pronounce squall line?

Squall line, also known as unstable line or air pressure surge line. A mesoscale weather. It is a discontinuous line of air pressure and wind, with a small range and a short life history. In meteorology, a squall line refers to a narrow strong convective weather belt, with a small scope and a short life history, and sudden changes in air pressure and wind force. When it arrives, there will be strong weather phenomena such as sudden change of wind direction, sharp increase of wind force, sudden rise of air pressure and sudden drop of temperature.

From the weather radar chart, squall lines are like candied haws, which are worn in a string? Thunderstorms or cumulonimbus clouds. In the vicinity of the squall line, besides the violent changes of wind, air pressure and temperature, there are usually violent weather processes such as lightning, rainstorm, hail and tornado.

Squall lines often occur in the warm area before the cold front in the spring and summer transition season, and they often appear in the typhoon front, mostly from March to September. Before the occurrence, it was mostly sunny and hot weather, with high temperature, weak wind, chaotic wind direction, high air humidity, sultry weather and thunderstorm conditions, which mostly occurred in the afternoon to night.

Generally speaking, squall line is a member of strong convection family (lightning, hail, tornado), which has great energy and strong destructive power and cannot be taken lightly.

plant conditions

The collision of two air masses with different characteristics is a necessary condition for the formation of squall line. The most common situation is that a cold air mass collides with a warm air mass, but sometimes dry air collides with wet air. In either case, there will be wind shear in the sky. When the direction and speed of two adjacent winds are different, wind shear will occur.

It can make the rising air leave the cloud top. Most squall lines begin with dry, dense cold air. Although squall line belongs to mesoscale weather system, its formation and development are related to a certain large-scale weather situation. It mainly occurs in the warm area before the ground cold front 100 ~ 500 km.

Squall lines are generated in stratification with strong potential instability (see atmospheric static stability). This unstable stratification is mostly caused by the cold advection in the middle or upper layer superimposed on the warm and humid airflow in the lower layer. Squall lines are also related to high-altitude rapids, which often occur in areas where the vertical shear of rapids or winds is large.