How do They Predict the Weather

The simple fact of the matter is that weather is unpredictable. So how is it that we can gather information and make predictions about what conditions on Planet Earth will be like?

Most weather phenomena occur as a result of the movement of warm and cold air masses. The border between these bodies of air are known as ‘fronts’, and it’s here that the most exciting weather, including precipitation and wind, occurs.

As a body of air passes across different types of terrain – such as over the oceans, low-lying areas or even mountainous regions – air temperature and moisture levels can change dramatically. When two air masses at different temperatures meet, the less dense, warmer of the two masses rises up and over the colder. Rising warm air creates an area of low pressure (a depression), which is associated with unsettled conditions like wind and rain.

We know how a frontal weather system will behave and which conditions it will produce down on the ground. The man who first brought the idea of frontal weather systems to the fore in the early 20th Century was a Norwegian meteorologist called Vilhelm Bjerknes.

Through his constant observation of the weather conditions at frontal boundaries, he discovered that numerical calculations could be used to predict the weather. This model of weather prediction is still used today.

Since the introduction of frontal system weather forecasting, the technology to crunch the numbers involved has advanced immeasurably, enabling far more detailed analysis and prediction. In order to forecast the weather with the greatest accuracy, meteorologists require vast quantities of weather data – including temperature, precipitation, cloud coverage, wind speed and wind direction – collected from weather stations located all over the world. Readings are taken constantly and fed via computer to a central location.

Technology is essential to both gathering and processing the statistical data about the conditions down on Earth and in the upper atmosphere. The massive computational power inside a supercomputer, for example, is capable of predicting the path and actions of hurricanes and issuing life-saving warnings. After taking the information collected by various monitors and sensors, a supercomputer can complete billions of calculations per second to produce imagery that can reveal how the hurricane is expected to develop.