Subtracting Negative Numbers: A Real-Life Example (from Weather Forecast)

What's the purpose of subtracting negative numbers? Where would you need this mathematical skill? Let's explore a practical example from the work of meteorology specialists and see how they use subtraction of negative numbers for weather forecast.

Subtracting Negative Numbers for Predicting Thunderstorms


Mathematics plays a crucial role in making weather forecasts accurate and reliable. Meteorologists use mathematical models to analyze vast amounts of data, including temperature, humidity, wind speed, and air pressure, to predict weather patterns. 

One particularly valuable mathematical concept for weather forecasting is the use of negative numbers. These numbers play a significant role in predicting thunderstorms.

What causes thunderstorms?

Ever wondered what causes thunderstorms? In short – they happen when the atmosphere becomes unstable.

But what makes the atmosphere unstable? An unstable atmosphere occurs on very hot days, where warm air mass rises rapidly—so rapidly that when it reaches high altitudes, its temperature remains higher than the surrounding atmosphere.

For instance, the temperature of the lifted air mass might be -5 degrees Celsius, while the surrounding atmosphere might be -11 degrees Celsius (as shown in the animation below).

Animation demonstrating the ascent of warm air. At high altitude, its temperature is -5°C, while the surrounding air temperature is -11°C.

Subtracting Negative Numbers for calculating Lifted Index

What is Lifted Index?

Meteorologists use the term Lifted Index to describe this difference between temperatures. It’s calculated by subtracting the temperature of the lifted air mass from the temperature of the surrounding atmosphere.


In our example, we subtract two negative numbers: from -11 we subtract -5. The Lifted Index is, therefore:

\[-11 – (-5) = -6\]

A negative Lifted Index indicates an unstable atmosphere. The more negative it is, the more unstable the air, and the higher the probability of a thunderstorm. This method is one of the ways meteorologists predict thunderstorms.


This example demonstrates the practical application of subtracting negative numbers in meteorology. Calculating the Lifted Index is a standard practice used on a daily basis. While there are advanced technological solutions like satellites and weather balloons for measuring temperatures, basic mid-school mathematics remains invaluable for the necessary calculations.

Try it in interactive simulation!

We’ve created a special interactive simulation where you can try making a thunderstorm forecast by calculating the Lifted Index through subtracting negative numbers. Click on the picture below to access this simulation.

Screenshot of the simulation for calculating Lifted Index through subtracting negative numbers.


You can easily verify the accuracy of this information and explore more on your own:

Video version

We also have a video version available! It provides more in-depth information, additional examples, and explains how knowledge in physics, chemistry, geography, and biology is essential for understanding weather and climate. Check out the preview below or subscribe to the full video.

Further Reading:

Curious to discover more about how negative numbers are applied in real life? The following article explains how negative numbers are used in Smart Agriculture:

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