Why is predicting the weather so difficult..?

The Lorenz equation and Chaos theory.

Throughout the following days, I saw some articles on Facebook mentioning that the Meteorology Department is incompetent. So I thought of expressing my opinion on it. Just as everything else, there is more to this than what meets the eye. People blame the meteorology department not knowing the facts that I wish to share with you. All right. Let's begin...

Prof. Edward Lorenz (1917 - 2008)

First of all, predicting the weather is a scientific process. The weather has a mathematical model governed by a set of equations. To be precise a set of Ordinary Differential Equations (ODE's). This system of equations is known as the "Lorenz Equations" in credit of the MIT Mathematician and Meteorologist Professor Edward Norton Lorenz.

Secondly, The Lorenz Equations exhibit "Chaos". It results in chaotic solutions for certain parameter values and initial conditions. (Skip this sentence if it bothers you).This was first discovered by Prof. Lorenz himself.

Now let's have an insight into what Chaos is. Being simple to the best it can be, it sounds as follows... Consider a normal equation. Suppose you substitute a value having decimals into it (eg. 25.63 ). Suppose the answer you get is X. Now suppose you round off the value (eg. 25.6) and substitute it into the same equation. Then the answer you get is quite close to X. But this is not the case in systems that exhibit Chaos. If you substitute values after rounding them off, the final answer will start deviating drastically from the predicted answer, over time !!! (Simply you won't get even near to what you expect ). Prof. Lorenz noticed this for the first time when he rounded off meteorological data and substituted it into his model. He noticed that the predictions made went far off the actual over time.

This discovery led him to pioneer a theory known as "Chaos Theory". This explained to the world why predicting weather is so difficult.

The Lorenz fractal from which the "Butterfly Effect" gets its name

Now, over to our meteorology department... Why are their predictions always incorrect. Well, the first thing to notice here is that the predictions are not ALWAYS incorrect! There are many correct predictions. But what our eye catches are the incorrect ones. The other thing (Now this is solely my opinion), compared to other developed countries our country may not have the cutting-edge equipment to collect meteorological data (We even do not have a real-time data logger yet). So if the measurements are even slightly off the acceptable tolerance limits, it can cause the prediction to be significantly different from the actual outcome of those atmospheric conditions.

I must note that the motif of this article is to divert your attention to the mathematics of weather prediction. Neither I nor the Lorenz equations are responsible for the incompetence of the staff IF there are any. But what I want to highlight is that even though the staff is highly competent, the inherent Chaos of the Lorenz equation will cause mispredictions. So next time you blame the Meteorology department, think again...!