How we use technology to predict weather and the accuracy of these predictions

Meteorologists use satellites, radar, weather balloons, ground stations, and computer models to track and predict weather. Here is an in-depth look at the tools used:

1. Collecting Data

• Satellites – Observe cloud cover, storm development, temperature, sea surface conditions, and moisture in the atmosphere.

• Radar – Tracks precipitation, storm intensity, and movement. Doppler radar can detect wind patterns inside storms, helping identify tornadoes.

• Weather stations – Ground-based instruments measure temperature, humidity, wind speed, and pressure.

• Weather balloons – Launched twice daily worldwide, carrying instruments that measure upper-atmosphere conditions.

• Aircraft & buoys – Provide data from oceans and high altitudes where ground coverage is limited.

2. Computer Models

Meteorologists feed all this data into Numerical Weather Prediction (NWP) models, which simulate the atmosphere using physics and math.

Different models (e.g., the Canadian GDPS, the European ECMWF or the U.S. GFS) are run multiple times with slightly different starting conditions to create ensemble forecasts, showing a range of possible outcomes.

High-performance supercomputers are required to process the massive amount of data quickly.

3. Forecasting Tools

Short-range forecasts (hours to a few days): Rely heavily on radar, satellite, and local observations. These are usually very accurate.

Medium-range forecasts (3–7 days): Based mainly on global models. Accuracy decreases with time, but it is generally reliable for large-scale patterns.

Long-range forecasts (weeks to months): Look for climate trends like El Niño, not day-to-day details. Accuracy is limited.

4. Accuracy

We've all heard the phrase, the weather is always wrong. That's not at all true. 24-hour forecasts are around 90–95% accurate, three-day forecasts are 80–90% accurate and five-day forecasts are around 70–75% accurate.

With seven-day forecasts, accuracy drops further, though large patterns (like a major storm system) can still be predicted. Beyond 10 days, forecasts are mostly guidance rather than reliable predictions, because the atmosphere is chaotic.

Forecasts are very accurate for the next few days, moderately reliable up to a week, and mostly general guidance beyond that.