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  • Writer's pictureRuben GT

Cold, warm and occluded Fronts

You probably already heard of Cold and Warm Fronts, but do you know what they mean?

That the air will be colder or hotter?

Also, however, it doesn't stop there, that is just one of the characteristics of a Front!

So let's try to understand the phenomenon together and from the beginning, trying to simplify whenever possible.

A Front, whether Cold, Hot or Occluded, always originates from low atmospheric pressure, it's not possible to have Fronts in a stable air that is related to a High Atmospheric Pressure.

Without deviating from the topic that brought you here, it's crucial to understand a little about the Atmospheric Pressure to really understand the Fronts, let's go together.

Carta de superfície isobaras

In these images (called Surface Pressure Charts) that you can obtain on some weather forecast reference websites, (Europe) you can see 3 things that tell you a lot about what the weather will be like in the next few hours or days.

1st - The white lines with numbers printed all over the map.

They are called isobars and they connect points on the map where the atmospheric pressure is equal, this means that along the entire line that is always closed, the pressure value is the same.

Alta e baixa pressão atmosférica

2nd - The approximation of these same lines.

The closer they are, the stronger the wind will be in that region of the map, the same can be said for when they are very far away, meaning very weak or almost no wind;

Wind at high and low atmospheric pressures

3rd - Representations of a solid line with small triangles that point towards its movement and semicircles.

These are the Fronts and if you notice, they always originate in areas of low atmospheric pressure.

Why is that?

Movimento vento baixa pressão atmosférica

Atmospheric Pressure, as the name suggests, is the value attributed to the "weight" that the air exerts over a certain region of the Globe, being considered high when its value is equal to or greater than 1013Mb (millibar).

(Physics explains Pressure as the Force exerted per area unit).

Therefore, when the hot air in a certain region rises, it creates a low pressure zone beneath it and the air underneath moves to fill this space, generating winds.

In this context, phenomena such as the origin of Fronts occur.

(the movement of a large mass of air).

When the pressure is very low, it leads to the formation of vertically developing clouds, increased wind intensity and, often, rain and storms.

Now that you know how fronts are formed, let's see what results from them and how we can identify them.

A front, whatever it may be, is created by types of air with different characteristics, in terms of temperature, humidity and density.

The Cold Front is identified by a rapid lowering of the temperature upon its arrival and by the formation of vertically developing clouds.

Representação animada de uma Frente fria

This is because the colder air comes in "like a wedge" and makes the warmer air in front of it rise and condense, forming increasingly vertical clouds and often causing rain and strong winds, as well as some storms until they completely pass.

At that time, there is, as a general rule, an "abrupt" improvement in cloud, rain and wind conditions.

Representação de uma Frente fria

Cold front

Warm Front, as the name suggests, a mass of warmer air that moves more slowly than a cold front and that, when "colliding" with the colder air in front of it, forms clouds, generally with greater horizontal than vertical development, as it is a less violent impact and with less energy than that of the cold front.

Representação animada de uma Frente quente

It can also cause rain clouds to form and is normally noticed by observing clouds that completely cover the surface of the sky in a homogeneous gray color (stratus).

Representação de uma Frente quente

Warm Front

Sometimes, the Cold Fronts, being masses of air that move faster than the Warm Fronts, when they reach them, form the so-called Occluded Front, resulting in a mixture of both phenomena.

Just as a curiosity, when these air masses stop moving, they form what are called Stationary Fronts.

The different existing fronts

To remind you of the names and shapes of the different clouds, you can see this image below or read my full article about clouds here.

Tipos de nuvens e suas localizações

Did you know that a simple line in an image of the Globe could tell us so much?

Feel free to share!

Don't forget to Dream, by the way.. with good weather to Fly.

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