We often hear the terms high pressure and low pressure when we hear weather reports . Low pressure means that the atmospheric pressure of a region is lower than the surrounding area ; when the situation is reversed, it is called high pressure. Every day, meteorologists collect barometric pressure readings measured simultaneously at weather stations around the world, and then update them on a map with the location of weather stations marked on it. Generally, storms or low pressures occur in temperate zonesmid-latitudes. It is formed by the movement caused by the colliding surface of two masses of warm and cold air that have different characteristics when they meet. The development of a low pressure system can be divided into four stages : early, mature, decay, and dissipation. The average lifespan of a storm is approximately seven days .


What is a squall?

It is an area of low atmospheric pressure that is surrounded by winds that move counter- clockwise at the north pole , and counter-clockwise in the southern hemisphere . They are low pressure systems like hurricanes and typhoons.

  • features
  • Types of squall
  • Formation of a storm
  • Effects edit
  • Representation
  • Examples


The main characteristics of the storm are:

  • They are bad weather settings .
  • They have abundant and thick cloudiness because when the air rises it cools, condensing the humidity.
  • Has heavy rainfall , gusts of wind, and electrical activity
  • Some storms can be formed by excess heat .
  • They may be associated with Atlantic polar fronts .

Types of squall

There are two types of storms, which are defined below:

  • Thermal : it is the rise of an air mass when its temperature is significantly higher than that of its surroundings. It occurs as a cause of excess heat and as it develops, it is common for an intense degree of evaporation to occur , followed by condensation and, as an inevitable consequence, a lot of precipitation .
  • Dynamics : they arise as a result of the rise of an air mass in the direction of the tropopause due to a pressure suffered by cold air masses , which manage to displace it. The tropopause is the highest limit of the troposphere , or the layer of the atmosphere that touches the Earth’s surface. These storms are classified in the group of subpolar phenomena and are barometric depressions in the middle of two high pressure zones and whose graphic representation has the shape of a valley .

Formation of a storm

A squall so usually begins when, along the polar front a mass begins to move southward air polar cold and dry , while a mass of tropical air , warm and humid start to move toward the north .

In the next phase, the undulation tends to intensify enormously and the polar air mass heads south, along with its cold front, while the tropical one does the same, but with its warm front.

In both situations there are precipitations which are more intense on the cold front . In the final phase of storm formation, the cold front completely traps the warm front, reducing its size and isolating it from the rest of the tropical air, eliminating the contribution of moisture and energy that comes from the south. It is at this moment that the occluded front is formed and, from this moment, the cyclonic storm will die out until the original shape of the polar front is restored. Finally, in the final phase of the storm are the same types of clouds that appear on the warm front.

Effects edit

Some of the effects of storms are as follows:

  • Winds gale force up to 120 kilometers per hour.
  • Landslides on roads and obstructions in communication routes.
  • Extensive and heavy rains .
  • Strong winds and atmospheric elevation.
  • Cloudy skies that lower temperatures.


Storms are atmospheric regions in which there is a predominance of low pressures . They are represented on the maps with the letter B which means low pressure or squall.


Some examples of storms that have affected certain places have been:

  • Borrasca tropical extra:  are also known by the name of cyclones of average latitude and systems are low pressure that are located in the middle latitudes of the earth and do not have the same characteristics of tropical cyclones or polar , but are related fronts called baroclines . They are a phenomenon that produces clouds and storms.
  • Borrasca Emma:  on her way through Andalusia , Spain , she left a total of one deceased, several injured and more than 1500 accidents. The most affected populations in addition to Seville were Huelva and Cádiz . Strong and big waves , torrential rains and many landslides was what left the passage of the storm.
  • Squall Ana:  rain , wind and a lot of snow was what left this squall in Spain in its wake.

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