How weather forecasts are created
Weather forecasting is a sophisticated process that blends cutting-edge technology, global collaboration, and expert analysis.
The journey from raw data to a reliable forecast involves three key stages:
- Understanding current weather conditions
- Feeding data into supercomputers
- Expert refinement
Understanding current weather conditions
Accurate forecasts begin with knowing what the weather is doing right now. Meteorological centres worldwide collect millions of observations every day, measuring variables like temperature, rainfall, pressure, wind, and humidity. These observations capture obeservations throughout the depth of the atmosphere and come from a variety of sources:
- Satellites: Providine global images from space.
- Land surface instruments: Measure weather conditions on the ground.
- Marine sensors: Capture data from the ocean’s surface and depths.
- Upper air devices: Reveal the three-dimensional structure of the atmosphere.
- Radar: Offers detailed rainfall data, down to scales of 1 km.
- Thunderstorm locators: Pinpoint thunderstorms and associated severe weather.
Originally, trained observers manually recorded weather data, but today, most observations are automated using advanced technology. These measurements are essential for identifying current weather phenomena like rain, snow, fog, or frost, and for determining their severity.
Feeding data into supercomputers
Once observations are gathered, they are fed into computer models that are used to calculate how the current weather will change over time. Supercomputers use these 'starting conditions' to run complex mathematical equations that simulate how the atmosphere will evolve. A process, known as data assimilation, fills in gaps where direct observations are missing - such as remote ocean areas or inaccessible land regions - by blending available data with model predictions.
The computer models are run many times, producing forecasts that range from a few hours ahead to climate predictions spanning decades. Meteorologists monitor these outputs around the clock, adjusting forecasts as needed to ensure accuracy.
Expert refinement
Meteorological expertise is crucial for refining forecast details. Experts interpret model outputs, consider local factors, and update forecasts to reflect real-world conditions. Collaboration between countries is vital, as weather systems in one region can quickly affect distant areas. We work closely with international partners to exchange data, ensuring comprehensive coverage.
Why observations matter
Observations not only support daily forecasts but also help track climate trends. By comparing current data to long-term averages, scientists can monitor how the climate is changing over decades or centuries. This information is increasingly important for understanding and responding to climate change, guiding decisions made by governments and industries.
The role of technology
Modern forecasting relies on powerful supercomputers to process vast amounts of data and run sophisticated models. These models have evolved significantly since their inception, enabling more accurate and timely predictions. You can find out more about the history of weather forecast models below, or take a look at our latest supercomputer, managed by Microsoft in the Azure Cloud.
Weather forecasting is a dynamic blend of global data collection, advanced computing, and expert analysis. It’s a process that’s continually evolving, helping us prepare for everything from daily weather changes to long-term climate shifts.