Can we forecast weather precisely?

Weather forecasts are useful. People attentively listen to them but complain that they go wrong or are not taken seriously. Forecasts today are more probabilistically reliable than decades ago. The advancement of atmospheric science, satellite imaging, radar maps and instantly updated databases has improved the art of predicting weather.

- BY Pror. KIRTHI TENNAKONE ([e-mail])

Yet can we predict weather patterns precisely? A branch of mathematics known as chaos theory says that weather can never be foretold with certainty.

The classical mechanics of Issac Newton governing the motion of all forms of matter, solid, liquid or gaseous, is a deterministic theory. If the initial conditions are known, the behaviour of the system at later instants of time can be precisely predicted. Based on this theory, occurrences of solar eclipses a century later have been predicted to an accuracy of minutes and seconds.

The thinking that the mechanical behaviour of systems in nature could always be accurately predicted based on their state at a previous instant of time was shaken by the work of the genius French Mathematician Henri Poincare (18641902).