First Warning Weather 101: What is busy?

HONOLULU (HawaiiNewsNow) – The terms “high pressure” and ‘low pressure’ almost always find their way into the vocabulary of weather presenters around the world.

What does that mean for the prediction?(HNN weather)

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

This term is often used by meteorologists... but what does it mean? — This term is often used by meteorologists… but what does it mean?(HNN weather)

And why should anyone care?

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

On land, pressure can be simplified to the weight of the air above you.(HNN weather)

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

However, this average weight fluctuates.(HNN weather)

We don’t feel the weight of the air above us because our bodies are built to resist the extra downward force of the atmosphere. This also applies to virtually 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 greeted with a much stronger downward force 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, that weight fluctuates regularly. This fluctuation is a good starting point for understanding high and low pressure systems.

Visualize this:

A low pressure system is when there is fewer air above you than the global average. There is no air above your head.
A high pressure system is when there is more air above you than the global average. The air piles up on top of your head.

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

Without upward movement there would be no weather.(HNN weather)

Nearly all weather is caused by the upward movement of air in the atmosphere, including thunderstorms, tornadoes, hurricanes and snowstorms.

High pressure > calm weather

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

The abundance of air molecules in a high-pressure system makes it difficult for weather systems... — The abundance of air molecules in a high-pressure system makes it difficult for weather systems to form.(HNN weather)

The excess of air particles makes it more difficult for the air to move upwards. This in turn leads to calm weather and sunny skies.

Low pressure > rain and storms

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

The lack of air above ensures that air can move upwards more easily. This in turn can lead to messy weather, rain and thunderstorms.

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