How is that we can predict the weather so accurately?

Numerical weather prediction – the computer-based generation of countless charts and tables that give forecasters a detailed picture of the air above – is one of the world’s modern miracles. Australians have come to rely on the Bureau of Meteorology’s forecasting ability, which has a huge impact on everything from planning crop planting to next Sunday’s picnic.

It was in 1904 that Norwegian atmospheric scientist, Vilhelm Bjerknes, suggested that meteorologists might be able to quantitatively predict the weather by applying the hydrodynamic and thermodynamic equations driving the atmosphere.

Bjerknes understood that the behaviour of a fluid, like the atmosphere, is governed by four basic laws – Newton’s Second Law of Motion, the First Law of Thermodynamics, the Ideal Gas Law and the Law of Conservation of Mass – and he reasoned that by applying the relevant equations at a series of points throughout the atmosphere and for progressively later times, the characteristics of the atmosphere could be predicted, and the consequent weather forecast.

Today with supercomputing power, continuing improvements in model resolution and physics, and large increases in observational data such as topography, local conditions, and variables like current temperature and humidity taken from various observation platforms and particularly orbiting and stationary weather
satellites, Bureau of Meteorology forecasters can get a clearer picture of initial starting conditions to model the atmosphere.