Part of the show Forecasting Weather and Climate
Steve in Norfolk asked:
On Tuesday morning, the BBC website five day forecast predicted that there would be rain. On Tuesday afternoon, the website had changed to predict five days of cloud and sun. How can the forecast for five days change within a few hours?
It's all to do with chaos, which is what Tim was mentioning earlier. The weather is chaotic, so there are situations where it can be very unpredictable.