Viewed from space, the sun shines on the earth globe, with continents represented by data symbols 0 and 1.

Using a computer model to make a forecast

Getting the current state of the atmosphere

Each day, the Met Office receives around half a million observations of temperature; pressure; wind speed and direction; humidity, and many other atmospheric variables.

However, there are large areas of ocean, inaccessible regions on land and remote levels in the atmosphere where we have very few, or no, observations. To fill in the 'gaps' we can combine what observations we do have with forecasts of what we expect the conditions in between to be. This is a process called data assimilation and is the first step for the supercomputer.

Calculating how the atmosphere will change

The next step is to calculate how the current atmosphere will change over time. To do this, the supercomputer uses a number of complex equations which are repeated many times. Each time the forecast is stepped a few minutes further into the future, and this enables us to produce forecasts from just a few hours ahead, to a climate prediction for the coming 100 years.

You can find out more in-depth information on weather forecasting models in our research area. 

Computer models have come a long way since they were first developed. You can find out more about the history of weather forecast models below, or take a look at our latest supercomputer, the Cray XC40.