HONOLULU (HawaiiNewsNow) – The term “high pressure” and “low pressure” are almost always found in the vocabulary of weather presenters around the world.

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

And why should we care?

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

In meteorological terms, pressure can be simplified to the weight of all the air particles above you. On average, 14.7 pounds of air are above you at any time.

We do not feel the weight of the air above us because our bodies are built to retain the additional downward force of the atmosphere. This is also true for almost all life on 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 times higher than that of the entire atmosphere.

Water is much heavier than air. Combining the weight of all the water particles above the ocean floor, you are greeted by a downward force much stronger than that of 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.

Visualize this:

• A low pressure system that’s when there is less looks above you than the global average. There is no air above your head.
• A high pressure system that’s when there is more looks above you than the global average. Air collects above your head.

Pressure is also linked to one of the most important aspects of weather: upward motion.

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

Anticyclone > calm weather

High pressure is generally associated with less weather due to the greater amount of air in the atmosphere.

Excess air particles make it more difficult for air to rise. 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 deficit of air particles in the atmosphere.

The air deficit above facilitates upward air circulation. This, in turn, can lead to severe weather, rain and thunderstorms.

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

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