Today's question: Why are hurricanes so unpredictable?
Hurricane forecasts have actually improved dramatically over the last 50 years, primarily as a result of the development of computer simulations or "models" of how the atmosphere behaves. Despite those improvements, the models still have varying degrees of accuracy. This is because we can simulate the atmosphere within a computer, but we can't duplicate it.
That would require billions of observations throughout the depth of the atmosphere around the world, plus the computing power to process that data, neither of which is currently technically possible.
This is where the role of the hurricane forecaster comes in.
The specialists at the National Hurricane Center have spent their careers working day in and day out with not only the specialized hurricane models, but with every sort of hurricane forecast problem.
It is their knowledge and experience about the strengths and weaknesses of the models plus their expertise about the specialized field of tropical meteorology that makes the forecasts as good as they are today.
Still, it must be recognized that very small changes in the atmosphere can lead to large changes in the strength or track of a hurricane.
Often, the observational data network, especially over the oceans where hurricanes develop, is not dense enough to detect those changes.
In order for hurricane forecasts to really be accurate, not only must the internal structure of the hurricane be correctly forecasted, but also changes in the surrounding atmosphere over thousands of square miles.
Then, the forecaster must correctly determine exactly how those changes in the hurricane and the atmosphere are going to interact with each other.
It's definitely a formidable task.
The average error in a 24-hour hurricane position forecast is currently around plus or minus 85 nautical miles, and increases to about 300 nautical miles by 120 hours.