HONOLULU (HawaiiNewsNow) – The terms “high pressure” and “low pressure” almost always finds its way into the vocabulary of weather presenters around the globe.

But what exactly is pressure? What is a pressure system?

And why should anyone care?

The difference between high and low pressure is sometimes the difference between sunshine and rain.

At the time of speaking, pressure can be simplified to the weight of all the air particles above you. On average, 14.7 kilograms of air is above you at any given time.

We don’t feel the weight of the air above us because our bodies are built to hold the added downward force of the atmosphere. This is also true of almost all life on the earth’s surface. Life evolved to support the weight of the entire atmosphere.

Pressure can also be measured in other fluids. For example, the pressure at the bottom of the ocean is several orders of magnitude greater than that of the entire atmosphere.

Water is much heavier than air. When you combine the weight of all the water particles above the ocean floor, you are met with a much stronger downward force than the weight of all the air above the earth’s surface.

On average, the weight of the atmosphere is 14.7 pounds. However, this weight fluctuates regularly. This fluctuation is a good starting point for understanding high and low pressure systems.

View this:

• A low pressure system is when it exists Less air above you than the global average. The air is missing above your head.
• A high pressure system is when it exists More air above you than the global average. The air gathers above your head.

Pressure also relates to one of the most important aspects of weather: upward movement.

Almost all weather is created by the upward movement of air in the atmosphere, including thunderstorms, tornadoes, hurricanes, and blizzards.

High pressure > calm weather

High pressure is usually associated with lighter weather due to more air in the atmosphere.

Excess air particles make it harder for air to move upward. This in turn leads to calm weather and sunny skies.

Low pressure > rain and thunderstorms

Low pressure is usually associated with active weather due to the scarcity of air particles in the atmosphere.

The air deficit above makes it easier for the air to move upwards. This in turn can lead to messy weather, rain and storms.

The atmosphere is fluid and constantly fluctuating. However, learning these meteorological concepts is a starting point for understanding the complexity of the atmosphere.

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