Weather is a chaotic system that is highly sensitive to initial variables, making long-term forecasts unreliable.
Despite careful planning and monitoring of forecasts, bad weather can still unexpectedly ruin our anticipated plans. Even with Google’s assurance of a “mostly sunny” weekend, the rain can disregard predictions and catch us off guard.
Most people have their own story of plans being disrupted by inaccurate weather forecasts. But why are weather forecasts so frustratingly unreliable? Why is it still a challenge to accurately predict the weather despite the advancements in technology?
How accurate are weather forecasts?
Weather forecasts often have mistakes, but not as frequently as one might think. We tend to focus on the errors, which makes it seem like forecasts are always incorrect.
A five-day forecast is actually quite accurate, with about a 90% success rate. For a seven-day forecast, the accuracy drops to around 80%. However, as more days are added, the uncertainty increases.
For a ten-day forecast, there is about a 50-50 chance of it being accurate. Beyond that, the reliability decreases significantly.
A seven-day forecast can be reasonably accurate, but beyond that, predictability diminishes. (Photo Credit: ojal/Shutterstock)
These numbers are an improvement compared to the past. A five-day forecast today is as accurate as a one-day forecast in 1980.
How does weather forecasting work?
Weather forecasting is a complex process that involves analyzing a vast amount of data, utilizing mathematical models, and computational power. Data from various sources, such as satellites, are collected and analyzed. Powerful computers use this data to generate predictions.
Significant amounts of data are gathered from sources like satellites to create weather forecasts. (Photo Credit: Andrey VP/Shutterstock)
The concept of using numerical analysis to forecast the weather originated in the 1920s with Lewis Fry Richardson’s work. With the advancement of supercomputers, this approach became more practical.
To make weather forecasts, multiple variables related to wind, temperature, pressure, and others need to be considered to determine the state of the atmosphere at a particular time. These variables serve as initial conditions that can be inputted into mathematical models. The models are developed based on patterns observed in historical data and the typical behavior of weather.
Improved data collection methods and the increasing processing power of computers have contributed to the significant improvement in weather forecasts today.
Why are weather forecasts inaccurate?
So, where do things go wrong? We rely on the current weather conditions to predict future weather. The complexity and multitude of variables involved in this process make weather prediction challenging.
Describing the state of the atmosphere involves many factors. (Photo Credit :mokokomo/Shutterstock)
The Theory of Chaos
Chaos theory was formulated as a result of a weather prediction experiment. In 1961, Edward Lorenz attempted to create a model for accurate weather forecasts. He input values representing various atmospheric variables into a computer to predict the weather.
During this experiment, he accidentally discovered something significant. When he rounded off the values to only three decimal places, instead of the original six decimal places, it produced drastically different outcomes. A small inaccuracy in the initial conditions resulted in forecasts that seemed unrelated to each other.
An Insight into Chaos
Chaos theory explains systems that exhibit extreme sensitivity to initial conditions. Weather is unpredictable because it is a chaotic system.
If we examine two chaotic systems with nearly identical initial conditions, in a short period of time, the slight variation grows into significant differences in the system’s state. Two forecasts that initially appeared very similar could quickly evolve into completely different weather conditions.
Impossibility of Perfection
We cannot account for all the variables that determine the weather’s state. Additionally, we cannot determine them with absolute accuracy. If, hypothetically, we could do both, then and only then could we have a system that predicts the weather with 100% accuracy.
However, this is not feasible. We can gather more data and enhance the accuracy of our data. We can utilize more advanced supercomputers and improve the resolution of our atmospheric imaging. Nevertheless, it is impossible to track every molecule and its trajectory in the atmosphere. Hence, our data will always be incomplete, leading to slightly inaccurate results. Assumptions will always be present, which can influence the final outcomes.
Weather forecasts can improve, but they can never be perfect. (Photo Credit :kalen/Shutterstock)
Looking Ahead
We have all experienced situations where we have criticized weather reports and meteorologists for providing inaccurate information, but from now on, let’s be more understanding. They are genuinely doing their best. The weather is simply very difficult to predict!
However, this does not mean that we should give up on understanding the weather. There may be limitations to how far in advance and how accurately we can forecast, but forecasting is continually improving.
A great reminder of this is the fact that hurricanes, which previously caused thousands of fatalities, now result in much lower death tolls. Weather forecasting may never be a flawless science, but it is an incredibly important one, and advancements indicate that it will only continue to improve!